DEBCO D7_10 - VGB PowerTech

DEBCO Contract No. TREN/FP7EN/218968/”DEBCO

D E B C O - Demonstration of Large Scale Biomass Co

Date: 15.03.2013

Activity Energy 2: Area ENERGY 2.2: Topic ENERGY 2007 2.2.4: Large Grant Agreement No. TREN/FP7EN/218968/”DEBCO Project acronym DEBCO Project title DE

Supply Chain Integration Delivery title D7.10 Advanced Biomass Co

Funding scheme Collaborative project Date of preparation 15 Actual submission date 15 Start date of project: 01.01.2008 Organisation name of lead contractor for this deliverable DEBCO Consortium Project website address http://www.debco.eu

Project co- funded by the European Commission

PU Public

PP Restricted to other programme participants (including the Commission Services)

RE Restricted to a group specified by the consortium (including the Commission Services)

CO Confidential, only for members of the consortium (including the Commission Services)

Contract No. TREN/FP7EN/218968/”DEBCO”

Demonstration of Large Scale Biomass Co-Firing and Supply Chain Integration

Energy 2: Renewable Electricity GenerationENERGY 2.2: Biomass ENERGY 2007 2.2.4: Large-scale co-firing

TREN/FP7EN/218968/”DEBCO

DEBCO

DEmonstration of Large Scale Biomass CO-Supply Chain Integration

D7.10 Advanced Biomass Co -Fir ing Guidebook ENEL – S. Gasperett i , P. Leoni GdF SUEZ – L. Smeeths USTUTT – A. Ful ler , J . Maier , E. Mil ler LABORELEC – Y. Ryckmans CERTH – M. Karampin is DOOSAN – B. L iv ingston VGB – U. Langnickel , S. Zimmerl ing

Collaborative project

15.03.2013

15.03.2013

01.01.2008 Duration: 60 months

DEBCO Consortium

http://www.debco.eu

funded by the European Commission within the Seventh Framework Programme

Dissemination Level

Restricted to other programme participants (including the Commission Services)

Restricted to a group specified by the consortium (including the Commission Services)

Confidential, only for members of the consortium (including the Commission Services)

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Renewable Electricity Generation

Firing and

Fir ing Guidebook

60 months

Framework Programme

�



Date: 15.03.2013

The authors of the present Guidebook the DEBCO Partners for their contribution to the

With particular regard to the Guidebook writing, the provided by: H.-J. Feuerborn,(Wrocław University of Techno(RSE); F. Sissot (Agriconsulting).



Acknowledgements

uthors of the present Guidebook on Advanced Biomass Co-Firing wish to thank all of heir contribution to the accomplishment of this challenging project.

With particular regard to the Guidebook writing, the authors gratefully acknowledge the help , L. Müller, U. Schirmer, A. Wecker (VGB);

aw University of Technology); L. Barta (MATÜZ); J. Kalivodova (ECN);F. Sissot (Agriconsulting).

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wish to thank all of accomplishment of this challenging project.

acknowledge the help U. Schirmer, A. Wecker (VGB); H. Pawlak-Kruczek

; J. Kalivodova (ECN); V. Fantini



Date: 15.03.2013

The co-firing of biomass materials or stations can lead to significant reductions in COdioxide capture and storage, it is possible to generate electricity with substantial negative CO2 emissions. The flexibility generation scenarios involvingintrinsically less constant and predictable

The DEBCO project has involved andemonstration work aimed at the further with coal as a mean for using renewable flarge scale Biomass CO-firing and supply ctechnical development project included in the FP7, and involves seventeen Partners from eight different EU

The general objectives of the research activities, large-scale demonstrations and longoptions.

This Guidebook is intended to provide a summary of DEBCO project with a particular focus on:

- The economical aspectsstructure, the local and international fuel supply chains and the main economic factors which may affect co-firing projects;

- The technical aspects, including the fuel characteristics and storage/handling requirements, the plant modifications required for control device performance, the utilisation/disposal of the ash and other discards from the power plants.

The principal outcomes and findings of the DEBCO project were obtained through the successful completion of the four ma

- The detailed assessment activities, which were selected tocircumstances in a European and at Rodenhuize PP

- R&D activities concerned with the details of the and integrity of six power plants;

- The performance of a number of faspects of both new and ongoing coview to increasing the co

- The development of the technical knowincluding power utilitieuniversities, in a subject area of increasing importance worldwide



Executive Summary

firing of biomass materials or Refuse Derived Fuels (RDF) in large coalstations can lead to significant reductions in CO2 emissions, and if combined with carbon

, it is possible to generate electricity with substantial negative he flexibility of operation of coal plants is very attractive in future

ing further development of the wind and solar energyconstant and predictable.

has involved an extensive program of research, component work aimed at the further development of the co-firing of

with coal as a mean for using renewable fuels in the near term. DEBCO (DEmonstration of firing and supply chain integration) is a collaborative

project included in the European Commission framework program seventeen Partners from eight different EU countries.

the DEBCO project have been achieved through a program scale demonstrations and long-term monitoring of the key co

intended to provide a summary of the key results and experiences with a particular focus on:

conomical aspects, including the political and regulatory framework, the marketstructure, the local and international fuel supply chains and the main economic factors

firing projects; The technical aspects, including the fuel characteristics and storage/handling requirements, the plant modifications required for co-firing, the boiler and air pollution control device performance, the utilisation/disposal of the ash and other discards from

principal outcomes and findings of the DEBCO project were obtained through the four main project activities:

The detailed assessment of three large-scale biomass co-firing , which were selected to represent different technical and soci

European context, i.e. at Fusina PP (Italy), at Kardia PP (Belgium);

activities concerned with the details of the co-firing impacts on the performance power plants;

The performance of a number of feasibility studies of the technical and economic new and ongoing co-firing activities in Poland and Hungary

view to increasing the co-firing ratio; The development of the technical know-how and experience of the

utilities, equipment suppliers, SMEs, research centres and , in a subject area of increasing importance worldwide.

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uels (RDF) in large coal-fired power combined with carbon

, it is possible to generate electricity with substantial negative attractive in future energy

wind and solar energy, which are

program of research, component testing and firing of biomass and RDF

uels in the near term. DEBCO (DEmonstration of ntegration) is a collaborative research and

framework program

have been achieved through a program of onitoring of the key co-firing

results and experiences of the

, including the political and regulatory framework, the market structure, the local and international fuel supply chains and the main economic factors

The technical aspects, including the fuel characteristics and storage/handling firing, the boiler and air pollution

control device performance, the utilisation/disposal of the ash and other discards from

principal outcomes and findings of the DEBCO project were obtained through the

firing demonstration technical and socio-economic

Kardia PP (Greece)

impacts on the performance

the technical and economic firing activities in Poland and Hungary, with a

the project Partners, , SMEs, research centres and



Date: 15.03.2013

1 Introduction ................................1.1 Purpose of the Guidebook

1.2 Overview of the co

2 Economical aspects2.1 Political framework and market structure

2.2 Economic indicators

3 Technical aspects ................................

3.1 Fuel quality and composition

3.2 Safety, handling and storage

3.3 Feeding and milling system

3.4 Boiler modification and performance

3.4.1 Boiler modification

3.4.2 Combustion and boiler performance

3.4.3 Slagging/fouling and corrosion

3.5 Air pollution control device performance

3.6 Ash utilisation................................

3.6.1 Rodenhuize - co

3.6.2 Rodenhuize - combustion of 100% wood pellets

3.6.3 Fusina - co-firing of RDF

3.6.4 Kardia - co-firing of cardoon biomass

4 Conclusions ................................

5 References ................................

6 Appendix A – DEBCO project power plants6.1 Rodenhuize Power Plant

6.1.1 Retrofitting ................................


6.1.3 Air pollution control devices

6.1.4 Utilisation of residues

6.2 Kardia and Meliti Power Plants (agricultural biomass/lignite co

6.2.1 Handling, storage and milling






INDEX

........................................................................................Purpose of the Guidebook ................................................................

Overview of the co-firing power plants studied within DEBCO

Economical aspects ................................................................Political framework and market structure ................................

Economic indicators ................................................................

................................................................

Fuel quality and composition ................................................................

Safety, handling and storage ................................................................

Feeding and milling system ................................................................

Boiler modification and performance ................................

Boiler modification ...........................................................................................

Combustion and boiler performance ................................................................

Slagging/fouling and corrosion ................................................................

Air pollution control device performance ................................

..........................................................................................

co-firing of wood pellets .............................................................

combustion of 100% wood pellets ................................

firing of RDF ................................................................

firing of cardoon biomass ..............................................................

.....................................................................................

......................................................................................

DEBCO project power plants ................................Rodenhuize Power Plant ................................................................

................................................................................................


Air pollution control devices ................................................................

Utilisation of residues ................................................................

Kardia and Meliti Power Plants (agricultural biomass/lignite co

Handling, storage and milling ................................................................

Boiler modification ...........................................................................................


Air pollution control devices ................................................................D7.10

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........................ 9

...................................... 11

firing power plants studied within DEBCO ............... 12

......................................... 15

................................................ 15

................................................ 19

............................................ 24

.................................. 24

.................................. 26

.................................... 29

...................................................... 32

...........................32

................................33

........................................34

................................................. 35

.......................... 37

.............................41

.............................................41

.................................................42

..............................42

..................... 43

...................... 45

..................................... 46

........................................ 46

.......................................46

................................53

.............................................54

......................................................55

Kardia and Meliti Power Plants (agricultural biomass/lignite co-firing) .... 56

..........................................57

...........................58

................................60

.............................................61



Date: 15.03.2013


6.3 Fusina Power Plant (RDF co




6.3.4 Utilisation of residu

6.4 Dorog and Mátra Power Plants (agricultural biomass co



6.5 Rokita (biomass co

7 Appendix B - New findings7.1 Erosion and corrosion laborator

7.2 Large-scale corrosion monitoring of pure wood

7.3 Lab-scale and pilot

7.4 Lab-scale combustion behaviour

7.5 Modelling activities

7.6 Lab-scale pyrolysis tests

7.7 Lab-scale additive testing




Fusina Power Plant (RDF co-firing) ........................................................



Air pollution control devices ................................................................


Dorog and Mátra Power Plants (agricultural biomass co-firing)



Rokita (biomass co-firing) ................................................................

New findings ...............................................................Erosion and corrosion laboratory tests ................................

scale corrosion monitoring of pure wood-dust firing

scale and pilot-scale deposition tests ................................

scale combustion behaviour ............................................................

Modelling activities ................................................................

scale pyrolysis tests ................................................................

scale additive testing ................................................................

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......................................................62

........................ 63

..........................................63

................................65

.............................................67

......................................................68

firing) .............. 69

..........................................69

................................70

....................................... 71

............................... 72

................................................... 72

dust firing ..................... 74

.............................................. 76

............................ 76

.................................................. 76

......................................... 77

....................................... 79



Date: 15.03.2013

Figure 1: CO2 €/tonne % for different technologies.Figure 2: Comparison of the biomass breakFigure 3: Options for direct and indirect coFigure 4: Biomass storage milling unit (1/3).Figure 5: a) after conversion to coal; b) Advanced Green, wood dust firing @ rows 2 & 3; c)

Max Green wood dust firing @ rows 1,2 & 3.Figure 6: Overview of the boiler installed at Kardi a PP.Figure 7: Boiler geometry of Kardia PP and schemati c representation of simulated burner

geometry. Figure 8: Scheme of the MSW management process.Figure 9: RDF reception area at Fusina PP.Figure 10: Dorog PP fuel handling and feeding syste m.Figure 11: The location and arrangement of burners in PC OP

measurements level by suction pyrometry probe.Figure 12: Innovative erosion test rig developed by RSE.Figure 13: Comparison of the erosion rates Figure 14: SEM- BSE pictures of the ferritic sample after 90 hours’ exposure at 535 °C,

windward (left) a nd lee side (right).Figure 15: SEM- EDX element mappings of the Alloy 617 after 90 hour s’ exposure at 660 °C,

windward side. Figure 16: Scheme of the analytical procedure.



LIST OF FIGURES

€/tonne % for different technologies.

Figure 2: Comparison of the biomass break -even prices. Figure 3: Options for direct and indirect co -firing of solid biomass or RDF. Figure 4: Biomass storage milling unit (1/3). Figure 5: a) after conversion to coal; b) Advanced Green, wood dust firing @ rows 2 & 3; c)

Max Green wood dust firing @ rows 1,2 & 3. Figure 6: Overview of the boiler installed at Kardi a PP. Figure 7: Boiler geometry of Kardia PP and schemati c representation of simulated burner

8: Scheme of the MSW management process. Figure 9: RDF reception area at Fusina PP. Figure 10: Dorog PP fuel handling and feeding syste m. Figure 11: The location and arrangement of burners in PC OP-130 boiler and temperature

measurements level by suction pyrometry probe. Figure 12: Innovative erosion test rig developed by RSE. Figure 13: Comparison of the erosion rates of the tested materials

BSE pictures of the ferritic sample after 90 hours’ exposure at 535 °C, nd lee side (right).

EDX element mappings of the Alloy 617 after 90 hour s’ exposure at 660 °C,

Figure 16: Scheme of the analytical procedure.

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9 22

29 47

Figure 5: a) after conversion to coal; b) Advanced Green, wood dust firing @ rows 2 & 3; c) 49 57

Figure 7: Boiler geometry of Kardia PP and schemati c representation of simulated burner 58 64 65 70

130 boiler and temperature 71 72 73

BSE pictures of the ferritic sample after 90 hours’ exposure at 535 °C, 75

EDX element mappings of the Alloy 617 after 90 hour s’ exposure at 660 °C, 75 77



Date: 15.03.2013

Table 1: Overview of the PPs studied within DEBCO.Table 2: Political framework and market structure a nalysis for different European countries.Table 3: IWPB sustainability principles (2).Table 4: Summary of the assumptions for the calculations of the biomass bre akTable 5: The six evaluated configurations.Table 6: Average composition of the analysed biomas s.Table 7: Average composition of the main analysed f uels.Table 8: Performan ce summary of the fuel handling systems.Table 9: Performance summary of the fuel milling an d feeding systems.Table 10: Emission limits of IED for new power plan ts with permit after 07.01.2013. Emission

limits are given as monthly average values and for comg/Nm³ @ 6% O 2.

Table 11: Emission limits of IED for existing power plants and power plants with permit before 27.11.2002. Emission limits are given as mon thly average valuco- firing as daily average in mg/Nm³ @ 6% O

Table 12: European standards for fly ash requiremen ts.Table 13: Requirements on fly ash for use in cement and in concrete.Table 14: Physical requirements for fly ash in acco rdance with EN 450Table 15: Long- term corrosion monitoring campaign.Table 16: Erosion rate estimation in coTable 17: Ranking of the erosion/corrosion seriousn ess in PPs.Table 18: Alloying com position of the exposed materials.Table 19: Composition of pyrolytic gases from wood biomasses.Table 20: Composition of pyrolytic gases from agroTable 21: Composition of pyrolytic gases from RDF.Table 22: Composition of pyrolytic gases from fu



LIST OF TABLES

Table 1: Overview of the PPs studied within DEBCO. Table 2: Political framework and market structure a nalysis for different European countries.Table 3: IWPB sustainability principles (2).

assumptions for the calculations of the biomass bre akTable 5: The six evaluated configurations. Table 6: Average composition of the analysed biomas s. Table 7: Average composition of the main analysed f uels.

ce summary of the fuel handling systems. Table 9: Performance summary of the fuel milling an d feeding systems. Table 10: Emission limits of IED for new power plan ts with permit after 07.01.2013. Emission

limits are given as monthly average values and for co-firing as daily average in

Table 11: Emission limits of IED for existing power plants and power plants with permit before 27.11.2002. Emission limits are given as mon thly average valu

firing as daily average in mg/Nm³ @ 6% O 2. Table 12: European standards for fly ash requiremen ts. Table 13: Requirements on fly ash for use in cement and in concrete. Table 14: Physical requirements for fly ash in acco rdance with EN 450 -1.

term corrosion monitoring campaign. Table 16: Erosion rate estimation in co -firing + USC steam cycle conditions.Table 17: Ranking of the erosion/corrosion seriousn ess in PPs.

position of the exposed materials. Table 19: Composition of pyrolytic gases from wood biomasses. Table 20: Composition of pyrolytic gases from agro -biomasses. Table 21: Composition of pyrolytic gases from RDF. Table 22: Composition of pyrolytic gases from fu el blends.

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13 Table 2: Political framework and market structure a nalysis for different European countries. 16

18 assumptions for the calculations of the biomass bre ak-even price. 21

24 25 25 28 31

Table 10: Emission limits of IED for new power plan ts with permit after 07.01.2013. Emission firing as daily average in

36 Table 11: Emission limits of IED for existing power plants and power plants with permit

before 27.11.2002. Emission limits are given as mon thly average valu es and for 37 39 40 41 67

firing + USC steam cycle conditions. 73 74 75 78 78 78 79



Date: 15.03.2013

APCD Air Pollution Control Device

AOI Angle Of Impact

BAT Best Available Technology

BFG Blast Furnace Gas

DEBCO DEmonstration

integration

CAPEX CAPital EXpenditure

CCP Coal Combustion Product

CIF Cost, Insurance and Freight

CRF Capital Recovery Factor

EC European Commission

ESP ElectroStatic Precipitator

ETA European

ETS Emissions Trading System

EU European Union

FGD Flue Gas Desulphuri

GC Green Certificate

IED Industrial Emission Directive

IFR Isothermal Flow Reactor

IWPB Initiative Wood Pellet Buyer

LCP Large Combustion Plant

LHV Lower Heating Value

LNCFS Low NOx Concentric Firing System

LOI Lost Of Ignition

MSW Municipal Solid Waste

OPEX OPerating EXpenditure

PC Pulverised Coal

PP Power Plant

RDF Refuse Derived Fuel

R&D Research & Development

RTD Research and

SCR Selective Catalytic Reactor

SGS Société Générale de Surveillance

SME Small Medium Enterprise

UBC UnBurned Carbon

USC Ultra Super Critical



ACRONYMS

Air Pollution Control Device

Angle Of Impact

Best Available Technology

Blast Furnace Gas

DEmonstration of large scale Biomass CO-firing and supply chain

integration CAPital EXpenditure

Coal Combustion Product

Cost, Insurance and Freight

Capital Recovery Factor

European Commission

ElectroStatic Precipitator

European Technical Approval

Emissions Trading System

European Union

Flue Gas Desulphurisation

Green Certificate

Industrial Emission Directive

Isothermal Flow Reactor

Initiative Wood Pellet Buyer

Large Combustion Plant

Lower Heating Value

Low NOx Concentric Firing System

Lost Of Ignition

Municipal Solid Waste

OPerating EXpenditure

Pulverised Coal

Power Plant

Refuse Derived Fuel

Research & Development

Research and Technical Development

Selective Catalytic Reactor

Société Générale de Surveillance

Small Medium Enterprise

UnBurned Carbon

Ultra Super Critical

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firing and supply chain



Date: 15.03.2013

1 Introduction The European Commission wishes to increase the share ofenergy consumption in Europe European Commission in spring 2007. At the end of 20accounted for 12.5% of overall energy consumption. In ordof electricity generation from renewable energy sources must increase from 1around 34% in 2020.

It was considered that wind energy and biomasscontributions to the achievement of these targets. Tpublished at the end of 2005, all cost-effective forms of electricity generation from biomass.considered to be one of the most

The co-firing of biomass in coal boilers is generation. As is illustrated in the bar chart below, ifiring, particularly as a retrofit to existing power plants,reduce CO2 emissions. The coDenmark, Belgium, The Netherlands, Poland, Italy and United Kingdom.

Figure

The government subsidy schemes incentives for biomass co-firing vary significantly within the European Union.

Typical co-firing plants in the power plant sector are in thMWel. The majority of the plants are equipped withbiomass co-firing is also applied other boiler designs.

The key advantages of biomass co

- the utilisation of existing capital equipment, with modest costs and fairly short project times for plant conversion

- the biomass fuel flexibility, parti



wishes to increase the share of renewable energy in in Europe to 20% by 2020. This was set as a binding target by the

European Commission in spring 2007. At the end of 2010, renewable energy sources .5% of overall energy consumption. In order to meet the

of electricity generation from renewable energy sources must increase from 1

wind energy and biomass, in particular, will make the most the achievement of these targets. The EC Biomass Action Plan, which was

published at the end of 2005, encourages the EU member States to harness the potential of effective forms of electricity generation from biomass. The co-firing of biomass is

most promising technologies.

coal boilers is an important technology for CO. As is illustrated in the bar chart below, in a number of countries biomass co

particularly as a retrofit to existing power plants, is one of the most economic ways to o-firing of biomass is practiced in numerous plants, especially in

Denmark, Belgium, The Netherlands, Poland, Italy and United Kingdom.

gure 1: CO2 €/tonne % for different technologies.

government subsidy schemes and other financial instruments that ring vary significantly within the European Union.

firing plants in the power plant sector are in the electrical output range of 50. The majority of the plants are equipped with pulverized coal firing systems, although

applied in fluidized bed systems (bubbling and ci

advantages of biomass co-firing include:

of existing capital equipment, with modest costs and fairly short project times for plant conversion; the biomass fuel flexibility, particularly at low co-firing ratios;

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renewable energy in the overall to 20% by 2020. This was set as a binding target by the

, renewable energy sources er to meet the targets, the share

of electricity generation from renewable energy sources must increase from 19.8% in 2010 to

the most significant Biomass Action Plan, which was

the EU member States to harness the potential of firing of biomass is

an important technology for CO2-neutral electricity countries biomass co-

is one of the most economic ways to firing of biomass is practiced in numerous plants, especially in

that provide national ring vary significantly within the European Union.

e electrical output range of 50-700 pulverized coal firing systems, although,

in fluidized bed systems (bubbling and circulated) and in

of existing capital equipment, with modest costs and fairly short project



Date: 15.03.2013

- the relatively high overall power generation efficiencies from biomassco-firing in large coal-fired power plants.

The co-firing of biomass materials or stations can lead to significant reductions in COdioxide capture and storage, it is possible to generate electricity with substantial negative CO2 emissions. The flexibility generation scenarios involvingintrinsically less constant and

The combustion of pulverised fueleffective technology in terms of CAPEX and OPEXstorage and transport purposes, it is normally most convenient and costtransport and store the biomass in a milled and pellet form. approach normally allows the reuse of boiler pressure parts in the furnace and

The DEBCO project has involved andemonstration work aimed at the further materials with coal as a mean for using renewable f(DEmonstration of large scale Biomass COcollaborative RTD project included in the seventeen Partners from eight different EU



the relatively high overall power generation efficiencies from biomassfired power plants.

firing of biomass materials or Refuse Derived Fuels (RDF) in large coallead to significant reductions in CO2 emissions, and if combined with carbon

, it is possible to generate electricity with substantial negative he flexibility of operation of coal plants is very attractive in futu

involving further development of the wind and solar energyand predictable.

ed fuel in the existing boiler of a coal power plant is in terms of CAPEX and OPEX for the combustion of dry biomass.

storage and transport purposes, it is normally most convenient and cost-transport and store the biomass in a milled and pellet form. In terms of CAPEX

allows the reuse of much of the fuel feeding and firing system and the furnace and boiler, with suitable modifications where necessary.


with coal as a mean for using renewable fuels in the near term. DEBCO (DEmonstration of large scale Biomass CO-firing and supply chain

project included in the EC framework program FP7seventeen Partners from eight different EU countries.

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the relatively high overall power generation efficiencies from biomass that apply when

uels (RDF) in large coal-fired power combined with carbon

, it is possible to generate electricity with substantial negative attractive in future energy

wind and solar energy, which are

in the existing boiler of a coal power plant is the most he combustion of dry biomass. For

-effective to handle, In terms of CAPEX, this

fuel feeding and firing system and the odifications where necessary.


uels in the near term. DEBCO hain integration) is a

framework program FP7, and involves



Date: 15.03.2013

1.1 Purpose of the Guidebook

The objectives of the DEBCO of research activities, large-scale demonstrations and longfiring options.

This research and testing has provided key insights into the following areas:

- The reliability and sustainability of biomass supply chain- The retrofit and optimis

coal-fired boilers; - The measurement of the key b

co-firing biomass; - The measurement of the per

co-firing biomass; - The characteristic and utilisation/disposal of the ash discards from coal boiler co

biomass.

In this Guidebook, the key results and experiences order to provide relevant information and plant operators interested

- The economical aspectsstructure, the local and international fuel supply chains and the main economic factors which may affect co-firing projects;

- The technical aspects, including the fuel characteristics and storage/handling requirements, the plant control device performance, the utilisation/disposal of the ash and other discards from the power plants.

The principal outcomes and findings of the DEBCO project were obtained through the successful completion of the four ma

- The detailed assessment were selected to represent European context, i.e. aPP (Belgium);

- R&D activities concerned with the details of the and integrity of six power plants;

- The performance of a number of faspects of both new and ongoing coview to increasing the co

- The development of the technical knowincluding power utilitieuniversities, in a subject area of increasing importance worldwide

The key of the DEBCO project are summarised in the following sections and are based on the experience with six co-firing coals, a variety of biomass types and a range of cothe biomass co-firing demonstration activities are presented of the research and development activit



Purpose of the Guidebook

DEBCO project have been achieved through a comprehensive scale demonstrations and long-term monitoring of the key co


eliability and sustainability of biomass supply chain and quality of biomass;optimisation of biomass co-firing technologies to existing pulverised

The measurement of the key boiler performance parameters of power boilers when

The measurement of the performance of the air pollution control devices when

The characteristic and utilisation/disposal of the ash discards from coal boiler co

results and experiences of the DEBCO project are information to project developers, combustion and boiler engineers

and plant operators interested in co-firing technologies. Particular focus is

conomical aspects, including the political and regulatory framework, the market structure, the local and international fuel supply chains and the main economic factors

firing projects; The technical aspects, including the fuel characteristics and storage/handling requirements, the plant modifications required for co-firing, the boiler and air pollution control device performance, the utilisation/disposal of the ash and other discards from

principal outcomes and findings of the DEBCO project were obtained through the four main project activities:

The detailed assessment of three large-scale co-firing demonstration activitiesrepresent different technical and socio-economic

context, i.e. at Fusina PP (Italy), at Kardia PP (Greece)

activities concerned with the details of the co-firing impacts on the performance power plants;

The performance of a number of feasibility studies of the technical and economic new and ongoing co-firing activities in Poland and Hungary

view to increasing the co-firing ratio; The development of the technical know-how and experience of the

utilities, equipment suppliers, SMEs, research centres and , in a subject area of increasing importance worldwide.

The key of the DEBCO project are summarised in the following sections and are based on firing configurations employing different plant configurations and

coals, a variety of biomass types and a range of co-firing levels. More detailed firing demonstration activities are presented in Appendix A

development activities are summarised in Appendix B.

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comprehensive program term monitoring of the key co-


and quality of biomass; firing technologies to existing pulverised

parameters of power boilers when

tion control devices when

The characteristic and utilisation/disposal of the ash discards from coal boiler co-firing

roject are described in ombustion and boiler engineers

focus is placed on:

framework, the market structure, the local and international fuel supply chains and the main economic factors



principal outcomes and findings of the DEBCO project were obtained through the

demonstration activities, which economic circumstances in a

and at Rodenhuize

impacts on the performance

the technical and economic firing activities in Poland and Hungary, with a

the project Partners, , SMEs, research centres and

The key of the DEBCO project are summarised in the following sections and are based on mploying different plant configurations and

firing levels. More detailed descriptions of A. The key findings .



Date: 15.03.2013

1.2 Overview of the co

The key features and main results of the six coThese include:

- Rodenhuize PP , located in Belgium agenerator and was the host site share up to 50 and, then,output to about 65% of the maximum output on coal firingbiomass firing in May 2011September 2011.

- Kardia PP , located in Greece and consists of four units: Units 300 MWel, and Units 3 and MWel. Each unit consists of areheating designed for lignite. biomass was performed at

- Meliti PP , located in Greece and capacity of 330 MWel. Commissioned in 2004, it is the newest and one of theefficient lignite-fired power plants.combustion of xylite/lignite, with the percentage ofbrown coal of similar rank to lignite.

- Fusina PP , owned by Enelpower plant consists of four pulveriand 2), and two 320-MWel bottom boilers, equipped with a Low NOAlstom Combustion Engineering (formerly ABB), a Selective Catalytic Reactfinal NOx reduction, an electrostatic precipitator (ESP) and a flue gas desulphurization (FGD) system. RDF/coal coinput basis.

- Dorog PP , located in Hungary and producing hot water for districtoperating boiler (Units 3, 5 and 6)tangential fired, natural circulation,430 °C and 35 bar abs. The design coal was of low heating value (12 MJ/kg) and of high ash content (25-30 %). Units 5 and 6 were redesigned for natural gas75% thermal input of biomass.

- Rokita PP , located in Poland and power plant (100 MWth, 22firing tests were performed up to 36% thermal input of biomassresidues and different bio-liquids)



Overview of the co -firing power plants studied within DEBCO

results of the six co-firing projects are prese

located in Belgium and owned by GDF Suez SA, has and was the host site for a demonstration of wood pellet co-

share up to 50 and, then, 100% thermal input, with a de-rating of the of the maximum output on coal firing. The unit started up

in May 2011, and it has been routinely operated

in Greece and owned by the Public Power Corporation SA (PPC)nits 1 and 2 (built in 1974 and 1975) with an installed capacity of and 4 (built in 1980 and 1981) with an installed capacity of 325

Each unit consists of a supercritical Benson type once-through boiler with single ing designed for lignite. A program of co-firing tests with cardoon and olive kernel

at biomass thermal input up to 10%.

located in Greece and owned by PPC, consists of one unit with an installed ommissioned in 2004, it is the newest and one of the

fired power plants. Unusually, Meliti PP was designed for combustion of xylite/lignite, with the percentage of the former being up to 32%.

l of similar rank to lignite.

, owned by Enel SpA, is located in North-Eastern Italy, in the Venice area. The power plant consists of four pulverised coal (PC) fired units: two 160-MW

boilers (Units 3 and 4). Units 3 and 4 are tangentially fired drybottom boilers, equipped with a Low NOx Concentric Firing System (LNCFS) designed by Alstom Combustion Engineering (formerly ABB), a Selective Catalytic Reactfinal NOx reduction, an electrostatic precipitator (ESP) and a flue gas desulphurization

RDF/coal co-firing tests were performed at up to around 5% on a thermal

located in Hungary and owned by Dalkia Energia Zrt, is a coproducing hot water for district heating, process steam and electric energy. There are 3

nits 3, 5 and 6), and 1 boiler (Unit 4) is on reserve. Units 3 and 4 are circulation, lignite boilers with a nominal steam capaci

. The design coal was of low heating value (12 MJ/kg) and of high %). Units 5 and 6 were originally designed identical

natural gas firing. The biomass/coal co-firing tests were performed up 75% thermal input of biomass.

located in Poland and owned by PCC Rokita SA, is a comb22 MWel) with tangential combustion boiler. The biomass/coal co

firing tests were performed up to 36% thermal input of biomass liquids).

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firing power plants studied within DEBCO

firing projects are presented in Table 1.

has a 285-MWel steam -firing at increasing

rating of the maximum power The unit started up on 100% operated in this way since

orporation SA (PPC), with an installed capacity of

with an installed capacity of 325 through boiler with single

firing tests with cardoon and olive kernel

onsists of one unit with an installed ommissioned in 2004, it is the newest and one of their most

, Meliti PP was designed for the co-the former being up to 32%. Xylite is a

Eastern Italy, in the Venice area. The MWel boilers (Units 1

Units 3 and 4 are tangentially fired dry-Concentric Firing System (LNCFS) designed by

Alstom Combustion Engineering (formerly ABB), a Selective Catalytic Reactor (SCR) for final NOx reduction, an electrostatic precipitator (ESP) and a flue gas desulphurization

firing tests were performed at up to around 5% on a thermal

is a co-generation plant , process steam and electric energy. There are 3

nit 4) is on reserve. Units 3 and 4 are lignite boilers with a nominal steam capacity of 50 t/h,

. The design coal was of low heating value (12 MJ/kg) and of high designed identical to Unit 4, but later

were performed up to

a combined heat and . The biomass/coal co-

(wood, agricultural



Date: 15.03.2013

Table 1:

Owner GDF Suez SA

Plant Rodenhuize

Capacity 285 MWel (180 MW/ 560 MWth

Boiler type PC dry-bottom boiler

APCDs Advanced Green: ESPMax Green: high-

Design fuel Hard coal / blast furnace gas

Co-firing fuel Wood pellets

Co-firing rate 2009: increase from 25 to 50%2012: demonstration for 100% (Max

Milling Separate

Injection New low NOx burners

Co-firing trials Light Green: 2005 wood

Advanced Green: 2009 wood

Owner Public Power Corporation SA

Plant Kardia

Capacity 300 MWel / 856 MW

Boiler type PC dry-bottom boiler

APCDs ESP

Design fuel Lignite

Co-firing fuel Cardoon

Co-firing rate Increase from 0 to 10

Milling Together with the coal

Injection Together with the coal

Co-firing trials Cardoon, olive kernel



: Overview of the PPs studied within DEBCO.

Enel SpA

Fusina

MWel / Max Green) 320 MWel / 820 MW

bottom boiler PC dry-bottom boiler

reen: ESP -dust SCR, ESP High-dust SCR, ESP, wet FGD

Hard coal / blast furnace gas Hard coal

RDF (biofraction > 60%)

2009: increase from 25 to 50% 12: demonstration for 100% (Max Green) Increase from 2.5 to 5

Separate

burners RDF is injected directly into the pulverised coal pipes

reen: 2005 wood

reen: 2009 wood RDF up to 5% thermal input

Public Power Corporation SA Public Power Corporation SA

Meliti

MWth 330 MWel / 870 MW

bottom boiler PC dry-bottom boiler

ESP, wet FGD

Xylite / lignite

Wood pellets, maize residue pellets

Increase from 0 to 10% Increase to 3.3%

Together with the coal Together with the coal

Together with the coal Together with the coal

olive kernels Wood pellets, maize

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MWth

bottom boiler

dust SCR, ESP, wet FGD

60%)

Increase from 2.5 to 5%

RDF is injected directly into the pulverised

RDF up to 5% thermal input

Public Power Corporation SA

MWth

bottom boiler

Wood pellets, maize residue pellets

Together with the coal


ood pellets, maize residue pellets



Date: 15.03.2013

Owner Dalkia Energia Zrt

Plant Dorog

Capacity 40 MWel / 160 MW

Boiler type 2 PC and 2 combined cycles

APCDs ESP

Design fuel Hard coal

Co-firing fuel Saw dust, sunflower wood chips

Co-firing rate 75%, 100%

Milling Beater mill coal and biomass milled separately

Injection Multi-fuel burners, injection of coal and biomass separately,recirculation for un

Co-firing trials straw like material, hull, ground corn stem



Energia Zrt PCC Rokita SA

Rokita

160 MWth 22 MWel / 100 MWth

and 2 combined cycles PC/ Combined heat and power

ESP

Hard coal

Saw dust, sunflower hull, sunflower pellets, Wood, rape, glycerol

10%, 36%, 40%, 80%

Beater mill coal and biomass milled Together with the coal

fuel burners, injection of coal and biomass separately, using external fuel recirculation for unburned fuel


straw like material, grain sorghum, sunflower hull, ground corn stem Barley pellets, ground corn stem

sorghum briquettes,

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th

PC/ Combined heat and power

Wood, rape, glycerol

%, 36%, 40%, 80%



pellets, ground corn stem, grain sorghum briquettes, sunflower hull



Date: 15.03.2013

2 Economical aspectsThe evaluation of the economic aspects was focused on the following issues:

• the political framework and

• the different fuel supply chains (local, international, woody biomass, agricultural biomass, etc.),

• the characteristics of different biomass fuels

• the sustainability requirements for solid biomass fuels.

The public deliverable D3.6 “Indicators and guidsupply chains” (1) is available on the DEBCO websiteprovides a detailed description of the project.

2.1 Political framework and market structure The key results of the political framework and market structure analysis are summarised inTable 2.

The results of the analysis of policpotential of biomass co-firing is not European countries. In a number of renewable energy incentive system. modification, and this is not conducive to market stability. The and renewable energy are poorly described,criteria, across Europe, leadsfiring projects.

A common approach across Europesustainability criteria, as pointed out by Esecurity for investment, and a higher propensity the development of fuel supply chains and of biomass co

The analysis of the market potential showthe European and international market forwith food supply, wood process industrystimulation of local markets for biomass fuelsector, and create new jobs in the agricultural

It is clear from the work on the demonstration of the supply chainmarkets for biomass fuels is a big challengebetween the agricultural sector and the power producsecurity of investment for both the local farmer and the power producer.

The cardoon supply chain for Kardia a longer test campaign, becauselocal authorities. A fuel supply chain based on maize residues for Kardia with two companies operatingbusiness operations and the handling of contracts. could not be established on a largeentity that could collect, store and deliver the



aspects The evaluation of the economic aspects was focused on the following issues:

political framework and market structure for biomass in the participating countries,

the different fuel supply chains (local, international, woody biomass, agricultural

of different biomass fuels,

the sustainability requirements for solid biomass fuels.

The public deliverable D3.6 “Indicators and guidelines for future implementation of fuel is available on the DEBCO website (http://www.debco.eu)

provides a detailed description of the activities performed within this aspect of the DEBCO

Political framework and market structure The key results of the political framework and market structure analysis are summarised in

analysis of policy framework show that the economic and efiring is not adequately recognised in the legislation of a number of countries, biomass co-firing is not included in the

incentive system. The national regulations are also subject to regular fication, and this is not conducive to market stability. The legal definition

le energy are poorly described, and the uncertainties in thes to a lack of security for investment in large sc

across Europe, at least for financial incentives and binding as pointed out by EURELECTRIC would lead to an improved level of

and a higher propensity for the private sector to become involved in the development of fuel supply chains and of biomass co-firing projects.

The analysis of the market potential shows clearly that there is significant the European and international market for solid biomass fuels, without significant interference

, wood process industry or land use issues. It is also considered that thestimulation of local markets for biomass fuels will help secure employment in the power

jobs in the agricultural and transport sectors.

the demonstration of the supply chains that theis a big challenge, requiring coordination and co

ector and the power producers. This cannot be security of investment for both the local farmer and the power producer.

ardoon supply chain for Kardia PP could only be established to provide biomass fuel for because the cultivation of cardoons was financially supported by

supply chain based on maize residues for Kardia PPing as intermediates between PPC and farmers, which facilitated

business operations and the handling of contracts. The supply chain for straw at Meliti could not be established on a large-scale basis, due to the inability to find

collect, store and deliver the biomass to the power plant.

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The evaluation of the economic aspects was focused on the following issues:

market structure for biomass in the participating countries,

the different fuel supply chains (local, international, woody biomass, agricultural

elines for future implementation of fuel (http://www.debco.eu). This document

this aspect of the DEBCO

The key results of the political framework and market structure analysis are summarised in

economic and environmental in the legislation of all of the

not included in the are also subject to regular legal definitions of biomass

in the sustainability for investment in large scale biomass co-

incentives and binding n improved level of become involved in

significant potential growth in significant interference

It is also considered that the secure employment in the power

s that the creation of local coordination and co-operation his cannot be achieved without

be established to provide biomass fuel for was financially supported by

PP was established, as intermediates between PPC and farmers, which facilitated

he supply chain for straw at Meliti PP inability to find a local business



Date: 15.03.2013

Table 2: Political framework and market structure analysis for different European countries

Belgium / Flanders

Type of support scheme Green certificate

Level

RES quota 6% Penalty: 125 €/MWhe in 2011,118 €/MWhe in 2012,100 €/MWhe in 2013Market: 90 Guaranteed: 85

Co-firing support 50% of GCs if biomass < 60%

Other characteristics / restrictions

Traceability criteria GCs granted according to energy balance of supply chain and reference CCGT

Co-firing in NREAP / Policy direction

Yes Policy supports higher biomass shares

Sustainability considerations

No sustainability criteriaTraceability of supply chain and energy balance considered in GCsLaborelec verification scheme

Biomass markets Low availability of local biomass sources / Restrictions in the use of wood (Flanders) Import of pellets & wood chips

Socio-economics & other considerations

Job retention in retrofitted power stations



Political framework and market structure analysis for different European countries

Belgium / Flanders Belgium / Wallonia Greece

Green certificate Green certificate Feed

RES quota 6%

€/MWhe in 2011, €/MWhe in 2012, €/MWhe in 2013

Market: 90 €/MWhe uaranteed: 85 €/MWhe

RES quota 11.25% Penalty: 100 €/MWhe Market: 65 €/MWhe Guaranteed:65 €/MWhe (2010 values)

150 15% increase if no public funding is received for the investment

50% of GCs if biomass < no GCs granted � only 100% biomass combustion supported

Yes, based on biomass thermal mixture

Traceability criteria GCs granted according to energy balance of supply chain and reference CCGT

Sustainability must be proven GCs granted according to CO2 balance of supply chain and reference CCGT

Not applicable

Policy supports higher biomass shares

Yes Policy supports large-scale dedicated biomass combustion

Not consideredNo national framework, only regional support

No sustainability criteria Traceability of supply chain and energy balance considered in GCs Laborelec verification

Sustainability criteria GC granted according to GHG balance of supply chain Laborelec verification scheme

No sustainability criteria

Low availability of local biomass sources / Restrictions in the use of wood (Flanders) Import of pellets & wood chips

Undeveloped, will be based on agrobiomass


Importance of coschemes in retention of regional incomeJob creation in agricultural sector

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Political framework and market structure analysis for different European countries.

Greece

Feed-in tariff

150 €/MWhe (> 5 MW) 15% increase if no public funding is received for the investment

Yes, based on biomass thermal share in fuel mixture

Not applicable

Not considered No national framework, only regional support

No sustainability criteria

Undeveloped, will be based on agrobiomass

Importance of co-firing schemes in retention of regional income Job creation in agricultural sector



Date: 15.03.2013

Hungary

Type of support scheme Feed-in tariff

Level

Depending on capacityFor > 50 MWPeak time: 29.56 Ft /kWh (98.5 €/MWh)Valley time: 26.46 Ft /kWh (88.2 €/MWh)Deep valley: time 10.8 Ft /kWh (36 €/MWh)

Co-firing support

Eligible only if biomass is >70% of thermal share (both monthly and yearly)If fossil fuel fraction > 50% feed-in tariff reduced by 10%.

Other characteristics / restrictions

Efficiency >30% for dedicated biomass combustion > 32% for co

Co-firing in NREAP / Policy direction

Yes Pushing to agrobiomass utilisation Invest in dedicated biomass boilers < 20 MWRetrofit old units to 100% biomass combustion

Sustainability considerations

No sustainability criteriaForest biomass must originates from maintainable forest cultivation Biomass fuel must not be edible by humans

Biomass markets Developed, issues with pricing in the past

Socio-economics & other considerations

Job creation in agricultural sector Job retention in retrofitted power stations

There are countries within Europe rigid criteria. There are some agreements between local authorities andIn either case, if sustainability requirements are established they are generallynational or local forest and agricultural regulations.

The Initiative of Wood Pellet Buyers (IWPB)sourcing and trading of woody biomass among its members. including representatives of the major European utilities



Italy Poland

in tariff Hybrid (Green certificate > 1 MW) Green certificate

Depending on capacity For > 50 MW Peak time: 29.56 Ft /kWh

€/MWh) Valley time: 26.46 Ft /kWh

€/MWh) Deep valley: time 10.8 Ft

€/MWh)

88.91 €/MWhe (2010), VAT excluded

RES quota 10.4% Penalty: PLN 267.95/MWh Market: PLN 250/MWh Guaranteed: PLN 197.21/MWh (2010 values)

Eligible only if biomass is >70% of thermal share (both monthly and yearly) If fossil fuel fraction > 50% �

in tariff reduced by

Yes, no restrictions

YesObligatory composition of agrobiomass in fuel mixture

Efficiency >30% for dedicated biomass combustion > 32% for co-firing

GC multiplier before 2013: 1.8 for traceable biomass supplied within 70 km radius or within frameworks agreements, 1.3 for other cases. Starting from 2013: see Ministerial Decree (14).

Excemption of RESe from excise duty: PLN 20/MWh No distinction between RES technologies

Pushing to agrobiomass

Invest in dedicated biomass boilers < 20 MWel or Retrofit old units to 100% biomass combustion

Considered and supported Policy favors local supply chains

Considered and supportedFavors agricultural biomass

No sustainability criteria Forest biomass must originates from maintainable forest cultivation Biomass fuel must not be edible by humans

No sustainability criteria Traceability critera for higher GC multiplier

No sustainability criteriaHigh quality wood excludedBiodegradability must be proved

Developed, issues with the past

Developed market for imports in heating sector Power sector is developing on domestic resources

Developed market with domestic resourcesConcerns of fiber board, furniture and pulp & paper industries increasing share of agrobiomass

Job creation in agricultural


Job creation in agricultural sector


within Europe without any sustainability criteria, and countries with rather some agreements between local authorities and electricity producers.

In either case, if sustainability requirements are established they are generallylocal forest and agricultural regulations.

Buyers (IWPB) (2) has proposed sustainability principles for the sourcing and trading of woody biomass among its members. This is a working panel

the major European utilities involved in the firing or co

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Poland

Green certificate

RES quota 10.4% Penalty: PLN 267.95/MWh Market: PLN 250/MWh

uaranteed: PLN 197.21/MWh (2010 values)

Yes Obligatory composition of agrobiomass in fuel mixture

Excemption of RESe from excise duty: PLN 20/MWh No distinction between RES technologies

Considered and supported Favors utilisation of agricultural biomass

No sustainability criteria High quality wood excluded Biodegradability must be proved

Developed market with domestic resources Concerns of fiber board, furniture and pulp & paper industries increasing share of agrobiomass


countries with rather electricity producers.

In either case, if sustainability requirements are established they are generally reliant on the

proposed sustainability principles for the is a working panel

involved in the firing or co-firing of



Date: 15.03.2013

wood pellets in large power plantsGénérale de Surveillance) and Control Unionposition paper (3), which was prepared in reaction to the recommendations of the European Commission. In this document, biomass are proposed.

An overview of the key principles of fuel sustainability that the IWPB plans to apply in the sourcing and trading of woody biomass

Table

Principle 1: GREENHOUSE GAS BALANCE (GHG)The greenhouse gas (GHG) savings along the entire

including production, processing, transport and end

Production of woody biomass does not take place at the

Production of wood biomass may not take place in areas with high biodiversity value, unless evidence is provided that the production of that raw material did not

Principle 4: PROTECTION OF SOIL QUALITYProduction of woody biomass should maintain or improve the soil quality.

Principle 5: PROTECTION OF WATER QUALITYProduction of woody biomass should not exhaust

Principle 6: PROTECTION OF AIR QUALITYProduction of woody biomass should avoid negative impact or significantly reduce impact on air quality.

Principle 7: COMPETITION WITH LOCAL BIOMASS APPLICATIONSProduction of woody biomass should not endanger food, water supply or subsistence means of communities

where the use of this specific biomass is essential for the

Principle 8: LOCAL SOProduction of woody biomass should respect property rights and contribute to local prosperity and to the welfare

of the employees and the local population.

Ethical issues that the organization should uphold proclaimed human rights, freedom of association and the right to collective bargaining, elimination all forms of

forced and compulsory labour, effective abolition of child labour, elimination of employment and occupation, promotion of greater environmental responsibility, high standards of business

integrity, including the work against corruption in all its forms.



wood pellets in large power plants, and of the key regulators such as the ) and Control Union. This proposal builds on the EURELECTR

which was prepared in reaction to the recommendations of the European . In this document, binding principles on the sourcing and trading of woody

An overview of the key principles of fuel sustainability that the IWPB plans to apply in the sourcing and trading of woody biomass (2) is provided in Table 3.

Table 3: IWPB sustainability principles (2).

IWPB SUSTAINABILITY PRINCIPLES

Principle 1: GREENHOUSE GAS BALANCE (GHG) The greenhouse gas (GHG) savings along the entire life-cycle, taking into account the whole supply chain

including production, processing, transport and end-use are at least 60 % with respect to reference fossil fuels.

Principle 2: CARBON STOCK Production of woody biomass does not take place at the expense of significant carbon reservoirs in vegetation

and soil.

Principle 3: BIODIVERSITY Production of wood biomass may not take place in areas with high biodiversity value, unless evidence is provided

that the production of that raw material did not negatively interfere with nature protection purposes.

Principle 4: PROTECTION OF SOIL QUALITY Production of woody biomass should maintain or improve the soil quality.

Principle 5: PROTECTION OF WATER QUALITY Production of woody biomass should not exhaust ground and surface water and should avoid or significantly limit

negative impacts on water.

Principle 6: PROTECTION OF AIR QUALITY Production of woody biomass should avoid negative impact or significantly reduce impact on air quality.

COMPETITION WITH LOCAL BIOMASS APPLICATIONSProduction of woody biomass should not endanger food, water supply or subsistence means of communities

where the use of this specific biomass is essential for the fulfilment of basic needs.

Principle 8: LOCAL SO CIO-ECONOMIC PERFORMANCE Production of woody biomass should respect property rights and contribute to local prosperity and to the welfare

of the employees and the local population.

Principle 9: ETHICS Ethical issues that the organization should uphold include at least health & safety, respect of internationally

proclaimed human rights, freedom of association and the right to collective bargaining, elimination all forms of forced and compulsory labour, effective abolition of child labour, elimination of discrimination in respect of

employment and occupation, promotion of greater environmental responsibility, high standards of business integrity, including the work against corruption in all its forms.

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regulators such as the SGS (Société . This proposal builds on the EURELECTRIC

which was prepared in reaction to the recommendations of the European binding principles on the sourcing and trading of woody

An overview of the key principles of fuel sustainability that the IWPB plans to apply in the

cycle, taking into account the whole supply chain % with respect to reference fossil fuels.

expense of significant carbon reservoirs in vegetation

Production of wood biomass may not take place in areas with high biodiversity value, unless evidence is provided negatively interfere with nature protection purposes.

Production of woody biomass should maintain or improve the soil quality.

ground and surface water and should avoid or significantly limit

Production of woody biomass should avoid negative impact or significantly reduce impact on air quality.

COMPETITION WITH LOCAL BIOMASS APPLICATIONS Production of woody biomass should not endanger food, water supply or subsistence means of communities

of basic needs.

Production of woody biomass should respect property rights and contribute to local prosperity and to the welfare

include at least health & safety, respect of internationally proclaimed human rights, freedom of association and the right to collective bargaining, elimination all forms of

discrimination in respect of employment and occupation, promotion of greater environmental responsibility, high standards of business



Date: 15.03.2013

Several documents from IWPB utilities were

- the Green Gold Label developed by Essent and Control Union in the Netherlands- the corporate approach developed by Drax

sustainability; - the agreement of Vattenfall with the

sustainable fuel (5); - the verification procedure developed by Laborelec and SGS in Belgium for the grant of

green certificates with sustainable solid biomass

2.2 Economic indicators

For a biomass co-firing retrofit or repoweringintegration of the biomass supply chain andmodel. In most cases, there is a and the biomass fuel under considerationadditional financial support to the scheme or the grant of green certificates. Tamong EU members states andsupport.

Within the DEBCO project, a simplified economic indicator was developed of the biomass break-even pexpected biomass prices in order to evaluate whether a particular biomass type can be considered as an economic option and whether it has the potential to generate revenue to the power plant to justify the capital investment involved in the conversion of the plant to biomass firing or co-firing. power production set-up is economically neutral to the plant operator.

The biomass break-even price is a function of three components:

The baseline price, which consists of the price of coal replaced minus the annualiinvestment cost per unit of biomass fuel energy:

,bio base coalp p= −

where:

- �� is the coal price (€/GJ), - � is the specific investment (- � is the unit net efficiency,- CRF is the capital recovery factor

calculate the annualised investment

The CRF value is given by the following equation:

(( )1

1

++⋅=

k

kCRF

where � is the project duration (yr) and

As can be seen from equation availability, while it decreases as the specific investment and efficiency increasemore efficient power plant utiliselectricity. Moreover, the baseline price decreases as the project to the effect of the CRF.



from IWPB utilities were examined, including:

the Green Gold Label developed by Essent and Control Union in the Netherlandsthe corporate approach developed by Drax Power Ltd. in the UK for biomass

the agreement of Vattenfall with the Senate of Berlin for the use o

the verification procedure developed by Laborelec and SGS in Belgium for the grant of green certificates with sustainable solid biomass.

Economic indicators

firing retrofit or repowering project, the power utility has to considerintegration of the biomass supply chain and the impact of biomass utilisation in

In most cases, there is a significant difference between the delivered and the biomass fuel under consideration. This is typically covered by

to the power production from biomass through a feedreen certificates. The level of support for bio-energy varies widely

among EU members states and, in some cases, co-firing is not considered eligible for

, a simplified economic indicator was developed even price at the plant gate. This price is compared with typical or

expected biomass prices in order to evaluate whether a particular biomass type can be considered as an economic option and whether it has the potential to generate

to justify the capital investment involved in the conversion of the firing. The calculations are performed on the basis that the coal

up is economically neutral to the plant operator.

even price is a function of three components:

which consists of the price of coal replaced minus the annualier unit of biomass fuel energy:

bio base coal

CRF

Availability

α η⋅ ⋅= − ,

€/GJ), is the specific investment (€/kWel of net capacity retrofitted), is the unit net efficiency,

capital recovery factor, which is multiplied by the total investment in order to ed investment cost.

is given by the following equation:

)) 1−+

i

ik,

is the project duration (yr) and is the discount rate.

equation (1), the baseline price increases with the cost of coal and availability, while it decreases as the specific investment and efficiency increase

ore efficient power plant utilises less biomass for the production of the same amount of Moreover, the baseline price decreases as the project duration is decreased

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the Green Gold Label developed by Essent and Control Union in the Netherlands (4); in the UK for biomass

Senate of Berlin for the use of biomass as a

the verification procedure developed by Laborelec and SGS in Belgium for the grant of

project, the power utility has to consider the ation in the business

delivered fuel cost of coal by the provision of ugh a feed-in tariff

energy varies widely firing is not considered eligible for

, a simplified economic indicator was developed for the estimation rice at the plant gate. This price is compared with typical or

expected biomass prices in order to evaluate whether a particular biomass type can be considered as an economic option and whether it has the potential to generate additional

to justify the capital investment involved in the conversion of the The calculations are performed on the basis that the coal

which consists of the price of coal replaced minus the annualised

(1)

the total investment in order to

(2)

(1), the baseline price increases with the cost of coal and availability, while it decreases as the specific investment and efficiency increase, since a

es less biomass for the production of the same amount of duration is decreased, due



Date: 15.03.2013

It should be noted that the baseline price is independent of the biomass thermal share, provided that the specific investment cost remains the same. Typically, for low biomass shares an optimal techno-economic level of substitution can be found, which specific investment.

The CO2 saving price, which takes into account neutral for the purposes of the European ETSbiomass results in a decreased cost of CO

, 2 ,bio CO bio basep p= +

where:

- � is the emission factor of coal - �� is the market price - �� is the lower heating value

The biomass support price,bio-energy and co-firing in particular.

, , 2 supbio feed in bio COp p p− = + ⋅

where �� is the level of support for biomaspower production (€/MWhel).

This depends on the market value of the Gfeed-in tariff and the system marginal price, depending on the type of the support scheme, and on any price modifiers that may apply.

A summary of the assumptions used for the calculations of the biomass breakpresented in Table 4.

Five cases are compared:

- The Rodenhuize PP in Flanders, Belgium, of wood pellets at 50% thermal share)

- The Rodenhuize PP in Flanders, Belgium, 100% wood pellet firing)

- One hard-coal PP in Italy, retrofitted for cobiomass sourcing for “short” distances

- One hard-coal PP in Italy, retrofitted for cobiomass sourcing for “long” distances

- One lignite PP in Greece, retrofitted for co

An electrical efficiency of 35% and availability of 7500 hours has been assumed for all cases. In addition, a CO2 emission cost of 10



It should be noted that the baseline price is independent of the biomass thermal share, provided that the specific investment cost remains the same. Typically, for low biomass

onomic level of substitution can be found, which

which takes into account the fact that biomass is considered as COneutral for the purposes of the European ETS. By displacing coal combustion

a decreased cost of CO2 emissions. This is calculated by

2, 2 ,

CObio CO bio base

coal

ef p

LHV

⋅= + ,

is the emission factor of coal i.e. the mass of CO2 emitted per unit mass of coal,is the market price of CO2 (€/tonne),

heating value of the coal.

support price, which takes into account the effect of the support scheme for firing in particular. It is calculated as:

, , 2 supbio feed in bio COp p pη= + ⋅ ,

is the level of support for biomass power production from co-firing or large

the market value of the Green Certificates or the difference between the in tariff and the system marginal price, depending on the type of the support scheme,

and on any price modifiers that may apply.

summary of the assumptions used for the calculations of the biomass break

in Flanders, Belgium, in the Advanced Green operat 50% thermal share);

in Flanders, Belgium, in the Max Green operation (repowered fofiring);

in Italy, retrofitted for co-firing at thermal shares of around 10%, biomass sourcing for “short” distances (< 70 km);

in Italy, retrofitted for co-firing at thermal shares of around 10%, biomass sourcing for “long” distances (>70 km), e.g. imported wood pellet

in Greece, retrofitted for co-firing at thermal shares of around 10%.

of 35% and availability of 7500 hours has been assumed for all cases. emission cost of 10 €/tonne is used.

D7.10

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It should be noted that the baseline price is independent of the biomass thermal share, provided that the specific investment cost remains the same. Typically, for low biomass

onomic level of substitution can be found, which minimises the

that biomass is considered as CO2 y displacing coal combustion co-firing

by the equation:

(3)

emitted per unit mass of coal,

support scheme for

(4)

firing or large-scale

or the difference between the in tariff and the system marginal price, depending on the type of the support scheme,

summary of the assumptions used for the calculations of the biomass break-even price is

in the Advanced Green operation (co-firing

in the Max Green operation (repowered for

firing at thermal shares of around 10%,

firing at thermal shares of around 10%, , e.g. imported wood pellets;

firing at thermal shares of around 10%.

of 35% and availability of 7500 hours has been assumed for all cases.



Date: 15.03.2013

Table 4: Summary of the assumptions for

Belgium,

Pcoal (€/GJ)

� (€/kWe) 330 for co

700 for biomass repowering

LHVcoal (MJ/kg)

Emission factor (tn CO2/tn coal)

Bioenergy support

GC: 100 GCs granted according to energy of supply chain (~ 80 % for wood pellets made of residues, 75% from round wood)Since 2011: -50 % of GCs if biomass < 60 %-70% of GCs if biomass = 100%-89% of GCs for Rodenhuize, Max Green (grandfathering)

From 2013 on:case by case banding> 20 M

The results of the estimation of the

The following estimated delivered fuel to apply:

- Imported wood pellets with a typical cost of 8 the Endex Wood Pelletspower plants in Belgium, which cost bulk transportation

- Imported wood pellets with a typical cost of 10.9 further increase of 0.7 tax, handling costs and transport costs with truck from Thessaloniki harbour a lignitefired power plant. The total cost is thus estimated at about 11.6

This represents an increase of 45% to that for plants in Belgiumestablished market for biomass pellets in Greece, higher shipping costs estimation.



assumptions for the calculations of the biomass break

Belgium, Flanders Italy

3 3

330 for co-firing 700 for biomass repowering 330

25 25

2.29 2.29

GC: 100 €/MWhe GCs granted according to energy balance of supply chain (~ 80 % for wood pellets made of residues, 75% from round wood)

50 % of GCs if biomass < 60 % 70% of GCs if biomass = 100% 89% of GCs for Rodenhuize, Max Green

From 2013 on: case by case banding> 20 MWel

Power plants in operation before 2013

GC: 90 €/MWhe Multiplier:

1.3 for supply chains > 70 km

1.8 for supply chains < 70 km and framework

agreements From 2013: incentives

based on a bid mechanism are planned (14).

System marginal price ~

estimation of the biomass break-even prices are presented in Figure

delivered fuel costs for relevant biomass supply chains

Imported wood pellets with a typical cost of 8 €/GJ CIF Rotterdam, as estimated from the Endex Wood Pellets (6). This is considered to be typical of the biomass costs for power plants in Belgium, which typically have easy access to port facilitiescost bulk transportation, e.g. via barges. Imported wood pellets with a typical cost of 10.9 €/GJ CIF Thessaloniki, Greece. A further increase of 0.7 €/GJ to the fuel cost at the plant gate is imposed btax, handling costs and transport costs with truck from Thessaloniki harbour a lignite

The total cost is thus estimated at about 11.6 €/GJ.

This represents an increase of 45% for the biomass fuel delivered cost in Greece compafor plants in Belgium. It is considered that the main reason is the lack of an

for biomass pellets in Greece, hence the low bulk volume trade, and the higher shipping costs estimation.

D7.10

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biomass break-even price.

Greece

2

330

5.4

0.667

Feed in tariff 150 €/MWhe + 15 % if no

public funding for investment

System marginal price ~ 70 €/MWhe

even prices are presented in Figure 2.

biomass supply chains are assumed

€/GJ CIF Rotterdam, as estimated from . This is considered to be typical of the biomass costs for

typically have easy access to port facilities and low

€/GJ CIF Thessaloniki, Greece. A €/GJ to the fuel cost at the plant gate is imposed by harbour

tax, handling costs and transport costs with truck from Thessaloniki harbour a lignite-€/GJ.

for the biomass fuel delivered cost in Greece compared main reason is the lack of an

hence the low bulk volume trade, and the



Date: 15.03.2013

Figure 2 :

As can be seen, the breakRodenhuize PP would be below level of the support for bioenergy from conoted that the Max Green retrofit was possible due to a special agreement between the plant operator and the Flemish authorities that granted 89% of the GCs instead of the stan70% for repowered plants. At 70%, the profit margin would have been very small.

Greece and Italy have a higher biomass breakFlanders and the wood pellet cost CIF Rotterdam. However, in both countries there are some critical issues to consider:

- For Greece, the biomass breakwood pellet costs at the plant gate. The development of a market for the power sector and the establishment of longfor the imported wood pellets.result in a feed-in tariff decrease for cowas not explicitly considered by the Greek NREAP. As a result, plant operators Greece are currently focussources, with lower fuel costs.

- Italy is a major importer consumption in 2012 was 1.9 million tonSince imported wood pellets can claim higher prices in the domestic heating sector, it is unlikely that co-firing initiatives will be based on wood pellet imports.traditional biomass sources, such as forest residues and already being utilised in other sectors, such as domestic heating, or for existing power plants and are unlikely candidates for cobiomass fuels for co-firing will be currently olive prunings in the South of Italy, or new energy crops, such as Short Rotation

-

4

8

12

16

20

Greece Italy - 1.3 GC

Fu

el

Co

st (

€/G

J)



: Comparison of the biomass break-even prices.

As can be seen, the break-even biomass price for the Advanced Green operation of would be below the wood pellet cost CIF Rotterdam as a result of the low

level of the support for bioenergy from co-firing at thermal shares below 60%noted that the Max Green retrofit was possible due to a special agreement between the plant operator and the Flemish authorities that granted 89% of the GCs instead of the stan

At 70%, the profit margin would have been very small.

Greece and Italy have a higher biomass break-even price than the repowering case in Flanders and the wood pellet cost CIF Rotterdam. However, in both countries there are some

For Greece, the biomass break-even price is marginally higher than the estimated wood pellet costs at the plant gate. The development of a market for the power sector and the establishment of long-term contracts could bring about a decrease of the cost for the imported wood pellets. On the other hand, the current fiscal uncertainty could

in tariff decrease for co-firing power plants, and the case of cowas not explicitly considered by the Greek NREAP. As a result, plant operators

are currently focussing on developing supply chains from domestic biomass sources, with lower fuel costs.

importer of wood pellets for domestic heatingconsumption in 2012 was 1.9 million tonnes, the majority of which was importedSince imported wood pellets can claim higher prices in the domestic heating sector, it

firing initiatives will be based on wood pellet imports.traditional biomass sources, such as forest residues and agro-industrial residues, ar

ed in other sectors, such as domestic heating, or for existing power plants and are unlikely candidates for co-firing fuels. Instead, it appears that potential

firing will be currently under-utilised biomass sources, such as olive prunings in the South of Italy, or new energy crops, such as Short Rotation

Italy - 1.3 GC Italy - 1.8 GC Belgium, Flanders -

Rodenhuize

(Advanced Green)

Baseline CO2 Support

Wood pellets, imported, Greece

Wood pellets, CIF Rotterdam

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Advanced Green operation of the wood pellet cost CIF Rotterdam as a result of the low

at thermal shares below 60%. It should be noted that the Max Green retrofit was possible due to a special agreement between the plant operator and the Flemish authorities that granted 89% of the GCs instead of the standard

At 70%, the profit margin would have been very small.

even price than the repowering case in Flanders and the wood pellet cost CIF Rotterdam. However, in both countries there are some

higher than the estimated wood pellet costs at the plant gate. The development of a market for the power sector

term contracts could bring about a decrease of the cost rent fiscal uncertainty could

the case of co-firing was not explicitly considered by the Greek NREAP. As a result, plant operators in

ains from domestic biomass

of wood pellets for domestic heating (7). The total s, the majority of which was imported (8).

Since imported wood pellets can claim higher prices in the domestic heating sector, it firing initiatives will be based on wood pellet imports. Other

industrial residues, are ed in other sectors, such as domestic heating, or for existing power

firing fuels. Instead, it appears that potential ed biomass sources, such as

olive prunings in the South of Italy, or new energy crops, such as Short Rotation

Belgium, Flanders -

Rodenhuize (Max

Green)

Wood pellets, imported, Greece



Date: 15.03.2013

Coppice in the North. A major incentive for such initiatives is thmultiplier used in the case of short supply cha

It should be noted without financial support for biosaving price, it is only possible to consider biomass fuels with a cost range of 2.7 In order to consider biomass increase to more than 50 €/tscenario, due to the higher emission factor of lignite over hard coal.

Overall, provided that a reliable biomsupport scheme is stable, coevaluations for Meliti PP indicated a payfiring scheme at low biomass thermal shares.

The above analysis does not cover the case of RDF comay not be considered eligible for financial support in some EU member states. However, RDF co-firing may still be economically profitable for the power plant operator due to the gate fee available for disposal of the



Coppice in the North. A major incentive for such initiatives is the increase of the GC multiplier used in the case of short supply chains (transport distance < 70 km) to 1.8.

It should be noted without financial support for bio-energy and considering only the COsaving price, it is only possible to consider biomass fuels with a cost range of 2.7 In order to consider biomass prices of 8 €/GJ, the emission costs for CO

€/tonne. Co-firing with lignite would benefit more from such a scenario, due to the higher emission factor of lignite over hard coal.

Overall, provided that a reliable biomass fuel supply can be secured and that the financial support scheme is stable, co-firing can be a low risk investment for utilities. Economic evaluations for Meliti PP indicated a pay-back of one year for the implementation of a co

omass thermal shares.

The above analysis does not cover the case of RDF co-firing. The biomass faction of RDF may not be considered eligible for financial support in some EU member states. However,

firing may still be economically profitable for the power plant operator due to the gate disposal of the waste.

D7.10

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increase of the GC ins (transport distance < 70 km) to 1.8.

energy and considering only the CO2 saving price, it is only possible to consider biomass fuels with a cost range of 2.7 – 3.5 €/GJ.

€/GJ, the emission costs for CO2 would have to firing with lignite would benefit more from such a

ass fuel supply can be secured and that the financial firing can be a low risk investment for utilities. Economic

back of one year for the implementation of a co-

he biomass faction of RDF may not be considered eligible for financial support in some EU member states. However,

firing may still be economically profitable for the power plant operator due to the gate



Date: 15.03.2013

3 Technical aspects The co-firing of biomass and RDF materials present some potential tecperformance and integrity of the power plant, including handling/storage logistics, combustion and boiler impacts, boiler efficiencontrol, ash quality and utilisation

The main comments and observation presented below are based on the six biomass coconfigurations employing different sharesdescribed in Table 5.

Summaries of the adopted solutions resolved are presented belowdemonstration is provided in Appendix

Table

Power Plant Main fuel

Rodenhuize Hard coal

Rodenhuize -

Kardia Lignite

Fusina Hard coal

Dorog Hard coal-

Rokita Hard coal

3.1 Fuel quality and composition

A high level of control of the delivered fuel quality and composition is essential for efficient power plant operation. Binding the delivered biomass and RDF

The most important physical properties calorific value and ash content. These physicapayments, but they also have systems and the modifications t

The chlorine and the sulphur contentelements may have an impact on the performmay help to increase the rates of corrosion of boiler components

For RDF, quality standards are already in effect for either directly applied or adapted for co

For international traded biomass fuels, IWPB has defined standards for wood pellets that could be adapted for other types of biomass. The IWPB standardto define quality standards for local biomass supply chains.



firing of biomass and RDF materials present some potential tec

performance and integrity of the power plant, including fuel compatibility and combustion and boiler impacts, boiler efficien

ash quality and utilisation.

comments and observation presented below are based on the six biomass coonfigurations employing different shares of biomass firing as well as

solutions and a commentary on those issues that still need to be are presented below. A more detailed description of the results of each co

in Appendix A.

Table 5: The six evaluated configurations.

Main fuel Secondary fuel (Biomass/RDF)

% thermal input secondary fuel

Hard coal Wood pellets 50

Wood pellets 100

Lignite Cardoons Olive kernels 10

Hard coal RDF 5

-lignite Saw dust, sunflower

hull, sunflower pellets, wood chips

> 50

coal

Wood, agriculture by-products as rape seed

and liquid biomass-crude glycerol and

SRF were used

36-50

Fuel quality and composition

the delivered fuel quality and composition is essential for efficient . Binding quality standards and stringent quality control

biomass and RDF fuels.

mportant physical properties of the delivered fuels are the and ash content. These physical properties are employed to control fuel

payments, but they also have an influence on the design of the handling and storage systems and the modifications to the power plant equipment.

he chlorine and the sulphur contents are also important for emissionsy have an impact on the performance of the emissions control equipment and

may help to increase the rates of corrosion of boiler components (9).

For RDF, quality standards are already in effect for different industry sectorseither directly applied or adapted for co-firing applications.

For international traded biomass fuels, IWPB has defined standards for wood pellets that could be adapted for other types of biomass. The IWPB standards could also be a template to define quality standards for local biomass supply chains.

D7.10

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firing of biomass and RDF materials present some potential technical risks to the fuel compatibility and

combustion and boiler impacts, boiler efficiency, environmental

comments and observation presented below are based on the six biomass co-firing different fuels, as

a commentary on those issues that still need to be of the results of each co-firing

% thermal input secondary fuel

Appendix A paragraph

6.1

6.1

6.2

6.3

6.4

6.5

the delivered fuel quality and composition is essential for efficient and stringent quality control are required for

the moisture content, employed to control fuel

the design of the handling and storage

are also important for emissions in that these ns control equipment and

different industry sectors, and can be

For international traded biomass fuels, IWPB has defined standards for wood pellets that s could also be a template



Date: 15.03.2013

The impact that a biomass fuel has on plant operation will be dependent also on the range of coals with which the biomass is to be coAn overview of the physical project, is given in the following

Table 6: Average composition of the analysed biomass

Fuel Standard

Cardoon I EN 14918

Cardoon II EN 14918

Cardoon EN 14918

Cardoon Pellets

Straw EN 14918

Straw Pellets EN 14918

Miscanthus EN 14918

Willow EN 14918

Poplar EN 14918

Paulownia EN 14918

Wood Pellets BE I EN 14918

Wood Pellets BE II EN 14918

Wood Pellets EN 14918

RDF GR EN

RDF IT EN 15400

RDF EN 15400

RDF Fusina ASTM

Analyses performed by: IFK – Institut für FeuerungsTechnology, Hellas (D3.3); Enel Engineering and Research.

PS IE – Pellet study, Institute for Energy and Environment *a.r. – as received; **d.b. – dry basis

Table 7: Average composition of the main

Fuel Standard

Black Coal

Lignite

Fusina Coal ASTM

Kardia Lignite ASTM

Kardia Lignite

Analyses performed by: IFK – Institut für FeuerungsTechnology, Hellas (D3.3); Enel Engineering and Research.

PS IE – Pellet study, Institute for Energy and Environment *a.r. – as received; **d.b. – dry basis



The impact that a biomass fuel has on plant operation will be dependent also on the range of coals with which the biomass is to be co-fired.

average properties of fuels, analysed by Partners within the roject, is given in the following Table 6 and Table 7.

Average composition of the analysed biomass.

Standard Moisture

[wt %, a.r.*]

LHV [MJ/kg,

a.r.*]

Ash [wt %, d.b.**]

EN 14918 8.3 14.70 9.45

EN 14918 13.8 15.20 7.73

EN 14918 15.4 14.67 8.63

6.8 14.33 9.50

EN 14918 6.68 16.19 7.07

EN 14918 5.95 17.38 9.60

EN 14918 6.48 16.08 6.74

EN 14918 6.25 18.41 1.93

EN 14918 2.66 17.41 1.71

EN 14918 8.15 16.55 0.93

EN 14918 9.0 16.80 0.64

EN 14918 - - 2.30

EN 14918 6.4 17.56 1.73

EN 15400 22.7 12.32 16.22

EN 15400 - - 22.10

EN 15400 3.0 17.56 15.27

ASTM 8-20 17-23 15-20

Institut für Feuerungs- und Kraftwerkstechnik (D3.3); CERTH – Centre for Research & 3.3); Enel Engineering and Research.

Pellet study, Institute for Energy and Environment (Institute for Energy and Environment (IE), 2006)

Average composition of the main analysed fuels.

Standard Moisture [wt %, a.r.*]

LHV [MJ/kg,

a.r.*]

Ash [wt %, d.b.**]

2.7 – 14.0 20 - 32 1 - 15

50 - 60 2 - 10 3.6 - 18

ASTM 3-9 26 6.5-15 0.0

ASTM 53.9 5.43 29.32

DIN 52.25 5.25 35.22

Institut für Feuerungs- und Kraftwerkstechnik (D3.3); CERTH – Centre for Research & Enel Engineering and Research.

Pellet study, Institute for Energy and Environment (Institute for Energy and Environment (IE), 2006)

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The impact that a biomass fuel has on plant operation will be dependent also on the range of

nalysed by Partners within the

Cl [wt %,

a.r*]

S [wt %,

a.r*]

1.84 <0.3*

0.19 0.22

0.22 0.22

1.0 0.11

0.25 0.00

0.14 0.03

0.04 0.28

0.02 0.34

0.03 0.03

0.01 0.26

0.01 <0.3*

0.03 <0.3*

0.03 0.21

0.78 <0.36*

0.94 0.27

0.55 0.13

0.7-0.9 0.2-0.4

Centre for Research &

(Institute for Energy and Environment (IE), 2006)

Cl [wt %,

a.r*]

S [wt %,

a.r*]

0.03-0.3 0.6-1.4

0-0.08 0.3-3.9

0.005-0.01 0.56-0.64

- 1.05

- 1.34

Centre for Research &

(Institute for Energy and Environment (IE), 2006)



Date: 15.03.2013

3.2 Safety, handling

The long-term storage and the handling of large amounts of biomass fuel present a number of significant new challenges to

Unlike coal, most biomass fuels should not be stored outside on the coal yard. materials tend to absorb water when exposed to the weather, and this can physical properties. There is also a tendency for organic compounds to be dissolved in the leaching liquors from large open stockpiles of biomass. significant levels of fines, and these can give rise to fugitive dust emissions from fuel reception and storage/handling facilities.

Biomass materials in stock piles also haat higher moisture contents and is caused by exothermal processes whose heat of reaction cannot be dissipated. These processes can be promoted by:

- an elevated temperature during/before storage- long storage times; - high storage volume; - high altitude of the stock- inappropriate ratio of stock volume and surface- storage of mixed fuels;- forming of rat-holing or arching in fuel silos

Stored biomass may emit certain gases like CO, COgas/air mixtures, and at a certain concentration can be harmfuIn addition biomass dust can form explosive mixtures with air, especially during transportation, conveying and moving the fuel within storage buildings.zoning are mandatory when firing dry dusty biomass li

The ignition and explosion characteristics of biomass fuel may exceed the known limits of more familiar solid fuels, and special attention and additional equipment may be necessary. In either case, the ignition and explosion limits of thto adapt the safety measures.

For the biomass fuel and its deposited dust these are:

- inflammability and flammability- smouldering temperature- spontaneous ignition temperature

And for its suspended dust:

- explosiveness (explosion limit- ignition temperature; - minimum ignition energy- maximum explosion overpressure- maximum rise in explosion pressure

Recommendations on the prevention of selfequipment for prevention of fire and explosions can be found in the VGBFire Protection in Power Plants”Plants” (11) as well as in “Health and Safety Aspects of Solid Biomass Storage, Transportation and Feeding” (15) and “The Pellet Handbook” (16).

Biomass refining can help to term for different fuel processing hydrothermal carbonisation. properties and may be easier to handle and store in large quantities.



Safety, handling and storage

term storage and the handling of large amounts of biomass fuel present a number of significant new challenges to the power plant operators.

Unlike coal, most biomass fuels should not be stored outside on the coal yard. terials tend to absorb water when exposed to the weather, and this can

physical properties. There is also a tendency for organic compounds to be dissolved in the ge open stockpiles of biomass. Many biomass materials

significant levels of fines, and these can give rise to fugitive dust emissions from fuel reception and storage/handling facilities.

Biomass materials in stock piles also have a tendency to self-heating. This occurs especially ntents and is caused by exothermal processes whose heat of reaction These processes can be promoted by:

an elevated temperature during/before storage;

high altitude of the stock; ratio of stock volume and surface;

; holing or arching in fuel silos.

Stored biomass may emit certain gases like CO, CO2, CH4, etc. These can form explosive gas/air mixtures, and at a certain concentration can be harmful to the operating personnel. In addition biomass dust can form explosive mixtures with air, especially during transportation, conveying and moving the fuel within storage buildings. ATEX measures and zoning are mandatory when firing dry dusty biomass like wood pellets.

The ignition and explosion characteristics of biomass fuel may exceed the known limits of more familiar solid fuels, and special attention and additional equipment may be necessary. In either case, the ignition and explosion limits of the biomass fuel have to be known in order to adapt the safety measures.

For the biomass fuel and its deposited dust these are:

nflammability and flammability; smouldering temperature; spontaneous ignition temperature.

explosiveness (explosion limits);

minimum ignition energy; maximum explosion overpressure; maximum rise in explosion pressure.

Recommendations on the prevention of self-ignition, on the storage of biomass and the tion of fire and explosions can be found in the VGB

Fire Protection in Power Plants” (10), “Fire and Explosion Protection in Biomass as well as in “Health and Safety Aspects of Solid Biomass Storage,

Transportation and Feeding” (15) and “The Pellet Handbook” (16).

help to overcome some of these challenges. “Refining” is a generic term for different fuel processing technologies like torrefaction, steam explosion or

The products of these processes show more “coalproperties and may be easier to handle and store in large quantities. The energy density of

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term storage and the handling of large amounts of biomass fuel present a number

Unlike coal, most biomass fuels should not be stored outside on the coal yard. Most biomass terials tend to absorb water when exposed to the weather, and this can affect their

physical properties. There is also a tendency for organic compounds to be dissolved in the Many biomass materials contain

significant levels of fines, and these can give rise to fugitive dust emissions from fuel

This occurs especially ntents and is caused by exothermal processes whose heat of reaction

, etc. These can form explosive l to the operating personnel.

In addition biomass dust can form explosive mixtures with air, especially during ATEX measures and

The ignition and explosion characteristics of biomass fuel may exceed the known limits of more familiar solid fuels, and special attention and additional equipment may be necessary.

e biomass fuel have to be known in order

ignition, on the storage of biomass and the tion of fire and explosions can be found in the VGB-Standards ‘’R108:

“Fire and Explosion Protection in Biomass Fired Power as well as in “Health and Safety Aspects of Solid Biomass Storage,

these challenges. “Refining” is a generic technologies like torrefaction, steam explosion or

processes show more “coal-like” The energy density of



Date: 15.03.2013

the refined materials tends to mill than the raw biomass material.

The commercial availability of the refined biomass fuels is still limited. Further R&D is needed to support the development of refined biomass fuels to becoco-firing at industrial scale.

There are several possibilities of fuel handling considered within DEBCO are summarised in Table 8.

The handling of the fuel needs much attention. grain form and aspect ratio, the bulk and particle and flow properties.

In most instances, the biomass and RDF materials will have specific handling and storage requirements. It is possible, in some circumstances to make use of the existing coal handling, bunkering, feeding and milling systems, with apif the fuel is in pellet or other densified form.



to be higher, and they may be more brittle in nature and easier to than the raw biomass material.

The commercial availability of the refined biomass fuels is still limited. Further R&D is needed to support the development of refined biomass fuels to become an alternative solid fuel for

several possibilities of fuel handling considered within DEBCO are summarised in

The handling of the fuel needs much attention. The key fuel properties are the gthe bulk and particle density, the moisture content, the

In most instances, the biomass and RDF materials will have specific handling and storage requirements. It is possible, in some circumstances to make use of the existing coal handling, bunkering, feeding and milling systems, with appropriate modifications, particularly

her densified form.

D7.10

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be higher, and they may be more brittle in nature and easier to

The commercial availability of the refined biomass fuels is still limited. Further R&D is needed me an alternative solid fuel for

several possibilities of fuel handling considered within DEBCO are summarised in

The key fuel properties are the grain size, the the moisture content, the pouring

In most instances, the biomass and RDF materials will have specific handling and storage requirements. It is possible, in some circumstances to make use of the existing coal

propriate modifications, particularly



Date: 15.03.2013

Table 8: Performanc

Power Plant Measure

Rodenhuize

The ship unloading activities and long storage The pellets are unloaded by means of a Grab crane and stored in a large automated warehouse.

From the warehouse, the pellets are conveyed by covered belt conveyor to the day silos at the Green milling installation.

For risk mitigation, it recommended that the necessary pre-cleaning devices are installed upstream of the main storage facility to avoid tramp and oversize material entering the storage.

Kardia No changes for short term test wanted.

Fusina

RDF is received at the station, and sent to two large storage silos.RDF is then fed out of the silos and conveyed through ferrous and nonmetal separation units tofour high speed hammer mills.

Dorog

The pellets weretransported to the a truck and handled very similarly to coal.



rformance summary of the fuel handling systems

Results Remark

The ship unloading long storage

The pellets are unloaded by means of a Grab crane and stored in a large automated

From the warehouse, the pellets are conveyed by covered belt conveyor to the day silos at the Max Green milling installation.

For risk mitigation, it is recommended that the

cleaning devices are installed upstream of the main storage facility to avoid tramp and oversize material entering the storage.

All buildings, installations and equipment shall be provided with all the necessary devices to protect, detect and fight explosion. ATEX compliant installation.

No changes for short term

The existing secondary fuel handling system is capable of handling biomass fuels with characteristics similar to olive kernels. The existing, not for biomass optimised fuel handling system, has little difficulties with olive kernels. The fuel weighting takes place after the mixing and may not be really accurate.

For long term operation with olive kernels

For long term operation with cardoonsis necessary

RDF is received at the station, and sent to two large storage silos. The RDF is then fed out of the silos and conveyed through

-ferrous metal separation units to four high speed hammer

s were transported to the plant by

handled very similarly to coal.

The proper feeding rate was worked out by determining the heating value of the fuels and weighed amount of coal and biomass was separately fed conveyed into the bunkers.

Feeding of biomass was not always continuous due to the inhomogeneous mixture. Wood-chips tended to form craters in the bunker and for avoiding plugging, mechanical agitation of the material was necessary.

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stems.

Remarks

For long term operation with kernels little difficulties.

For long term operation with cardoons individual solution

necessary.



Date: 15.03.2013

3.3 Feeding and milling system

There are basically five options for direct and indirect combustion of solid biomass or RDF in a pulverised-fuel boiler (Figure

1. When the proportion of biofuel is can be fed together with coal to together with coal through option and involves the implementation times.the fuel feeding systems.

2. The second option involves separate handling, metering and comminution of the biofuel, normally using hammer mills, of the burners or at the burners (conumber of biomass transport pipes across the boiler front,biomass feeding systems with the existing boiler control systems, for process control and safety reasons.

3. The third option involves the separate handling and comminution ofcombustion through a number of dedicated burners. This approach relatively high capital cost

4. The fourth approach involves the of the syngas and char in the main boiler as a substitute for coal.

5. The fifth approach is biomass to permit operation at higher

Figure 3: Options for direct and indirect co



ng and milling system

There are basically five options for direct and indirect combustion of solid biomass or RDF in Figure 3).

When the proportion of biofuel is relatively low, generally less than 10% by mass, can be fed together with coal to the coal mills (co-milling) and then be burned

ough the existing coal burners. In principle, this is the simplest option and involves the lowest capital investment costs and shortest project implementation times. This approach also carries the highest risk of malfunction of

fuel feeding systems. he second option involves separate handling, metering and comminution of the

, normally using hammer mills, and injection into the pulverised fuel upstream of the burners or at the burners (co-injection). This option requires the installation of a

transport pipes across the boiler front, and integration of the biomass feeding systems with the existing boiler control systems, for process control

The third option involves the separate handling and comminution ofcombustion through a number of dedicated burners. This approach

high capital costs, but can be applied at elevated co-firing levels.involves the gasification of the fibrous raw material and

the syngas and char in the main boiler as a substitute for coal. The fifth approach is similar to option 1, but involves the utilisationbiomass to permit operation at higher co-milling ratios.

Options for direct and indirect co-firing of solid biomass or RDF

D7.10

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There are basically five options for direct and indirect combustion of solid biomass or RDF in

generally less than 10% by mass, it milling) and then be burned

coal burners. In principle, this is the simplest costs and shortest project

also carries the highest risk of malfunction of

he second option involves separate handling, metering and comminution of the and injection into the pulverised fuel upstream

injection). This option requires the installation of a and integration of the

biomass feeding systems with the existing boiler control systems, for process control

The third option involves the separate handling and comminution of the biofuel with combustion through a number of dedicated burners. This approach normally has

firing levels. the fibrous raw material and injection

utilisation of torrefied

firing of solid biomass or RDF.



Date: 15.03.2013

Within the DEBCO project, only the first

- co-milling at Kardia PP;- separate milling, injection in PC lines, combustion in PC burners at Fusina, Dorog and

Rokita PPs; - separate milling and firing in

In all cases, it is essential that the size distribution of the milled fuel fed to the boiler is suitable for firing in a suspension flame. The injection of coarser material unstable flow of fuel, poor combustion conditions and (UBC) in the fly and furnace bottom

At low co-firing ratios, up to 5in pellet or granular forms may be comills or lignite beater mills. At normally based on hammer mills, is required.

This technology may not be suitable for very wet biomass materials which may blind the outlet screen and adhere to internal surfaces of the mill body. This can lead to poor product quality, higher power consumption andmilling is strongly recommended.

Hammer mills also require regular routine maintenancescreens, to maintain good performance

The experience gained within the DEBCO project and elsewhere has indicated that handling and feeding systemslike herbaceous biomass. Continuous feeding is not assured, to block and accumulate in the feeding system

Two solutions are suggested to overcome the problem of feeding herbaceous biomass in PCplants:

- Build a new facility for handling a- Pelletise the material at the source.

For the pneumatic conveying of the blowers for each conveying line has been most popular. Timportant advantages:

- Reduced blockage risk, - Good dust/air ratio control- Constant and controllable

The dust/air ratio is an important parameter, which is controlled to ensure proper opthe burners. Excessive dust/air ratios on the combustion prices.



, only the first three options were investigated:

milling at Kardia PP; separate milling, injection in PC lines, combustion in PC burners at Fusina, Dorog and

separate milling and firing in dedicated burners at Rodenuize PP.

In all cases, it is essential that the size distribution of the milled fuel fed to the boiler is suitable for firing in a suspension flame. The injection of coarser material

flow of fuel, poor combustion conditions and increased levels of unburned carbonfly and furnace bottom ashes.

up to 5-10% on a heat input basis, a wide range of biomass materials in pellet or granular forms may be co-milled successfully with coal in vertical spindle coal

At higher biomass and RDF shares, dedicated milling equipment, ased on hammer mills, is required.

may not be suitable for very wet biomass materials which may blind the outlet screen and adhere to internal surfaces of the mill body. This can lead to poor product

igher power consumption and lower throughput. For this reason, milling is strongly recommended.

regular routine maintenance, i.e. replacement of the hammers and good performance and an acceptable mill product quality.

gained within the DEBCO project and elsewhere has indicated that s can be unsuitable for handling and feeding

biomass. Continuous feeding is not assured, and there is a tendency for fuel in the feeding system.

Two solutions are suggested to overcome the problem of feeding herbaceous biomass in PC

Build a new facility for handling and feeding (expensive solution); e the material at the source.

For the pneumatic conveying of the milled fuel to the boiler burners, the blowers for each conveying line has been most popular. This approach

Reduced blockage risk, because there are no splitter in the biomass conveying linesGood dust/air ratio control; Constant and controllable fuel flow rates.

The dust/air ratio is an important parameter, which is controlled to ensure proper opExcessive dust/air ratios can cause pulsations and can have a negative impact

D7.10

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separate milling, injection in PC lines, combustion in PC burners at Fusina, Dorog and

In all cases, it is essential that the size distribution of the milled fuel fed to the boiler is suitable for firing in a suspension flame. The injection of coarser material will result in an

of unburned carbon

on a heat input basis, a wide range of biomass materials milled successfully with coal in vertical spindle coal

dedicated milling equipment,

may not be suitable for very wet biomass materials which may blind the outlet screen and adhere to internal surfaces of the mill body. This can lead to poor product

s reason, drying prior to

, i.e. replacement of the hammers and and an acceptable mill product quality.

gained within the DEBCO project and elsewhere has indicated that coal handling and feeding baled and straw-

and there is a tendency for fuel

Two solutions are suggested to overcome the problem of feeding herbaceous biomass in PC

the use of dedicated approach has a number of

in the biomass conveying lines;

The dust/air ratio is an important parameter, which is controlled to ensure proper operation of have a negative impact



Date: 15.03.2013

Table 9: Performance summary of the f

Power Plant Process

Rodenhuize Milling and feeding

Kardia Milling

Feeding

Fusina

Milling

Feeding



Performance summary of the fuel milling and feeding systems

Adaptations Results

A dedicated system was installed.

Fast rotating mills were selected.

A pneumatic conveying system is used to transport the milled wood dust.

After a few weeks of operation the efficiency of grindability of the hammer mills decreased dramatically and the worn out material had to be replaced.

Regular routine maintenance of the mills is necessary to maintain good performance and non to increase the unburned particle fallout into the bottom ash hopper of the boiler.

No changes for short term test wanted.

No changes for short term test wanted.

No explosions or temperature increases in the mills were detected. The temperature values were within the usual range of mill operation and well within safe operation limits.

No accumulation of olive kernels in the mills.

Relevant accumulation of cardoon found in the mills after the test, even in themills not in use for cardoon.

Cardoon accumulation inthe feeding system wasnot initially observed, butduring a maintenance,significant cardoon quantities were found inseveral places along thefeeding line, remaining practically blocked.

RDF is milled in dedicated high-speed blade-type coal mills.

Owing to a gradual wear of hammers and screens, the RDF milling performancehas been observed to decrease significantly over the time if hammer mills are used.

Milled fuel conveyed pneumatically to Units 3 and 4, and the RDF is injected directly into the PC pipes, at a location just upstream of the primary air fans.

D7.10

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systems.

Remarks

After a few weeks of operation the efficiency of

hammer mills decreased dramatically and the worn out material had to be

Regular routine maintenance of the mills is necessary to maintain good performance and non

e unburned particle fallout into the bottom ash hopper of the

No explosions or temperature increases in the mills were detected.

he temperature values within the usual

range of mill operation and well within safe operation

olive

accumulation of mills

after the test, even in the not in use for

in system was

observed, but nance,

cardoon in e

remaining

Physical properties of olive kernels (small particle size, grindability) are similar to fossil fuels but not to herbaceous biomass.

al wear of the

RDF milling performance has been observed to decrease significantly over the time if hammer mills



Date: 15.03.2013

Power Plant Process

Dorog Milling and feeding

3.4 Boiler modification and performance


The injection of biomass or RDFsignificant impact on plant performance and integrity. the nature of the biomass, the installed equipmratios, major modifications are not required.Kardia PP, with 5-10% thermal input. the fuel handling and firing system are normally required, e.g. at Rodenhuize PP, with 50100% thermal input.

Within the DEBCO project, CFD modelling the modifications to the boiler and firing systems. velocity and temperature fieldsshould preferably be validated with experimental measurements, e.g. velocity, techemical species concentrations.

As stated above, at high biomass comodification of the fuel handling and firing systems are normally required, as at Rodenhuize power plant to 50% co-firing (advgreen). At Rodenhuize, the existing burners have been modified significantly for biomass firing. The inlet section of the primary air cross section with the inteconsidered that this shape has several

- The kinetic energy of the wood dust particles of the hexagon which is perpendicular to the wood dust

- The hexagonal shape wood dust all around the primary air tube

- The primary air tube can be turned in order to extend another side to the inlet wood dust flow

The wood dust is transported in dense phase independently from the primary air and is injected in a concentric way inside the primary pipe about one meter upstream the burner.



Adaptations Results

High capacity mills were installed.

Two separate fuel lines were used for coal and for the pellets so they did not mix before the flame.

The proper feeding rate was worked out by determining the heating value of the fuels and weighed amount of coal and biomass was separately fed conveyed into the bunkers.

Feeding of biomass was not always continuous due to the inhomogeneous mixture. Wood-chips tended to form craters in the bunker and for avoiding plugging, mechanical agitation of the material was necessary.

Boiler modification and performance

Boiler modification

mass or RDF into the furnace of a pulverised coal-fired boiler can have a significant impact on plant performance and integrity. Depending on the

e biomass, the installed equipment will require modification. For low coratios, major modifications are not required. This has been demonstrated at Fusina and

10% thermal input. For higher co-firing ratios, significant modifications to the fuel handling and firing system are normally required, e.g. at Rodenhuize PP, with 50

CFD modelling has proved to be of value for the assessment of ations to the boiler and firing systems. The activities have include

velocity and temperature fields, as well as the flue gas composition. The CFD simulations should preferably be validated with experimental measurements, e.g. velocity, techemical species concentrations.

As stated above, at high biomass co-firing levels and 100% biomass firing significant modification of the fuel handling and firing systems are normally required, as at Rodenhuize

firing (advanced green) and 100% wood pellet combustion (max the existing burners have been modified significantly for biomass

section of the primary air annulus has been redesigned with a hexagonal cross section with the internal surfaces completely covered with ceramic tiles

shape has several advantages:

The kinetic energy of the wood dust particles at the inlet is partly absorbed by the of the hexagon which is perpendicular to the wood dust flow,

shape contributes to the generation of an even wood dust all around the primary air tube,

he primary air tube can be turned in order to extend its lifetime by presenting another side to the inlet wood dust flow.

The wood dust is transported in dense phase independently from the primary air and is injected in a concentric way inside the primary pipe about one meter upstream

D7.10

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Remarks

The proper feeding rate was worked out by determining the heating value of the fuels and weighed amount of coal and biomass was separately fed conveyed

Feeding of biomass was not always continuous due to the inhomogeneous

chips tended to form craters in the bunker and for avoiding plugging,

of the

fired boiler can have a Depending on the co-firing ratio and

ent will require modification. For low co-firing This has been demonstrated at Fusina and

firing ratios, significant modifications to the fuel handling and firing system are normally required, e.g. at Rodenhuize PP, with 50-

of value for the assessment of included calculations of

The CFD simulations should preferably be validated with experimental measurements, e.g. velocity, temperature,

firing levels and 100% biomass firing significant modification of the fuel handling and firing systems are normally required, as at Rodenhuize

anced green) and 100% wood pellet combustion (max the existing burners have been modified significantly for biomass

redesigned with a hexagonal ceramic tiles. It is

is partly absorbed by the side

even distribution of the

lifetime by presenting

The wood dust is transported in dense phase independently from the primary air and is injected in a concentric way inside the primary pipe about one meter upstream of the inlet to



Date: 15.03.2013

Another challenge was to ensure efficient combustion of support fuel. During the operation attogether with coal through a number of the burners. Icombustion was well controlledpulverised coal flames. It is considered, however, that the flame were too high, and the larger without completely burning out

After retrofitting the firing system for operation at 100% biomass, the burner was modified, based on the results of experimental testsmodifications were to the primary air temperature and flowand the secondary air swirl level


The impacts of biomass co-firing upon the details of the combustion system and the of the plant.

From a general point of view, the impact of the coto 5-10% on thermal basis, e.g at Kardia and Fusina PP, has been negligible.

For the Advanced Green project pulverized coal transport system were used for woodsedimentation in the fuel lines, the pipework had to be kept very highair velocities at the burner outletthe burner. There was evidence of high levels of UBC in the bottom and fly ashand fouling deposit formation in the furnace and the inlet to the burnout was not complete at the coarse fuel particles on heat transfer surfaces can create local reducing zones that favour slag formation.

After changing the burners and modifying the boiler for the Max Green configurationcombustion was much more stable, impingement on the furnace surfaces, and

At Kardia PP, the boiler efficiency of 10%. The mean values of the flue gas temperatures at various as well as after the ESPs, were measured. No significant changes were observed during cofiring. The flue gas volumes decrease

The only noticeable difference was a cardoon co-firing compared to those for 100% lignite firing

At Fusina PP, an assessment study has been carried out on the basis of operational conditions, at RDF thermal input varying from 0 to 5% and average unit load levels in the range 301-307 MWmeasured flue gas temperatures in the convective section indicatevariation in the boiler performance at the different RDF co

The measured superheater spray flow rates, which are best indicator of the heat absorption performance of the furnace, show no significant evidence to suggest that the cofurnace performance.



Another challenge was to ensure efficient combustion of the milled biomass without any During the operation at 50% biomass/coal co-firing, biomass was injected

together with coal through a number of the burners. In this operating conditioncombustion was well controlled, and the biomass combustion was supported by the pulverised coal flames. It is considered, however, that the wood particle velocities within the

larger wood particles were hitting the opposite membrane walls out.

fitting the firing system for operation at 100% biomass, the burner was modified, experimental tests, to obtain a self-sustaining stable

primary air temperature and flow rate, the secondary air flow level.

Combustion and boiler performance

firing on the performance and integrity of PC boilers depends details of the combustion system and the boiler, and the general operating

From a general point of view, the impact of the co-firing of biomass and RDF material at up 10% on thermal basis, e.g at Kardia and Fusina PP, on the performance of the boiler

roject at Rodenhuize the existing coal burners and part of the pulverized coal transport system were used for wood co-firing. In order to avoid pulsing and sedimentation in the fuel lines, the primary air flow rates and velocities in the pulverised coal

had to be kept very high, at 30 m s-1, or even faster. This resulted in at the burner outlets, causing the flame to be unstable and not

ere was evidence of flame impingement on the opposite and side wallsin the bottom and fly ashes. There was also evidence of increased slag

and fouling deposit formation in the furnace and the inlet to the convective the 43 metre level and it is known that secondary combustion of

particles on heat transfer surfaces can create local reducing zones that favour

After changing the burners and modifying the boiler for the Max Green configurationmuch more stable, lower levels of UBC in the ashes, no

on the furnace surfaces, and much less slagging.

Kardia PP, the boiler efficiency was not influenced by co-firing biomass at a coean values of the flue gas temperatures at various positions in the

as well as after the ESPs, were measured. No significant changes were observed during codecreased by only around 2% during the co-firin

The only noticeable difference was a doubling of the UBC levels in the bottom ashcompared to those for 100% lignite firing .

an assessment study has been carried out on the basis of operational conditions, at RDF thermal input varying from 0 to 5% and average unit load

307 MWel. The boiler data, i.e. the flue gas flow rates and the measured flue gas temperatures in the convective section indicated that there

in the boiler performance at the different RDF co-firing levels.

The measured superheater spray flow rates, which are best indicator of the heat absorption performance of the furnace, show no significant variation. This indicates that therevidence to suggest that the co-firing of the RDF material had any significant impact on the

D7.10

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biomass without any firing, biomass was injected

n this operating condition, the coal on was supported by the

velocities within the wood particles were hitting the opposite membrane walls

fitting the firing system for operation at 100% biomass, the burner was modified, stable flame. The main

, the secondary air flow rate

PC boilers depends eral operating regime

RDF material at up on the performance of the boiler

he existing coal burners and part of the . In order to avoid pulsing and

ies in the pulverised coal or even faster. This resulted in high primary

, causing the flame to be unstable and not well attached to the opposite and side walls and

There was also evidence of increased slag convective section. The

and it is known that secondary combustion of particles on heat transfer surfaces can create local reducing zones that favour

After changing the burners and modifying the boiler for the Max Green configuration, the in the ashes, no significant flame

firing biomass at a co-firing level positions in the the boiler,

as well as after the ESPs, were measured. No significant changes were observed during co-firing tests.

in the bottom ashes during

an assessment study has been carried out on the basis of 11 tests in different operational conditions, at RDF thermal input varying from 0 to 5% and average unit load

he boiler data, i.e. the flue gas flow rates and the d that there was no

The measured superheater spray flow rates, which are best indicator of the heat absorption This indicates that there is no

firing of the RDF material had any significant impact on the



Date: 15.03.2013

No major differences appear in the gas composition downstream of the economiser(NOx, O2 and CO concentrations were without co-firing. The UBC levels in the fly ashes were also unchanged when co

The only measurable differences absorption in the convective section being increased during the cothe normal boiler operating envelope and tsootblowing was negligible.

3.4.3 Slagging/fouling and corrosion

The inorganic constituents of biomass materials, and the ashes produced in combustion and other thermal processes, are of particular interest for plant designers and operators. These materials are very different in a number of important respects from coal ashes. They are not alumino-silicate systems, and commonly comprise mixtures of a limited number of relatively simple inorganic compounds, principally silica, and the oxides, sulphates, chlorides and phosphates of the alkali and the alkaline earth metals. In general terms, therefore, the biomass ashes are relatively rich in elements that are effective fluxes for coal ash systems and that tend to be volatile at elevated temperatures in combustion and oprocesses.

The overall result is that many of the potential impacts of the cocoal combustion and other thermal processing plants are associated with the changes in the ash composition and the ash behaviour that occur when coimpacts on plant operation and integrity that may be affected by biomass co

- The formation of fused or partlyreactors;

- The formation of bonded ash deposits on- The formation of aggressive ash deposits on high temperature surfaces, resulti

accelerated metal wastage;- The formation of aggressive ash deposits on surfaces at saturated steam

temperature, resulting in first convective heat exchangers

- The formation and emission of fi- The impact on the performance- The impact on the handling and the

thermal processes.

These impacts are dependent on a number of factors, including the chemistry and behaviour of the coal and the biomass ashes, the coto assess these risks and to minimise the impacts on plant performance are of key importance to the industry.

The industry has a suite of laboratory test procedures and other methods for the analysis and characterisation of coal ashes, and these have been applwhere necessary, to biomass ashes and the ashes from co

To date, the industrial experience has been principally with the comaterials in large pulverised coal boilers at relatively low cothe range of biomass materials of industrial interest is expanding rapidly, and the coratios are increasing. These trends will tend to result in an increase in the risks of significant ash-related impacts on the pe

In all of the demonstration plants, the slagging, fouling and corrosion evaluated with appropriate shortmaterials were being co-fired,



No major differences appear in the gas composition downstream of the economiserconcentrations were within the normal range of fluctuation experienced

levels in the fly ashes were also unchanged when co

differences in boiler performance were an increase in the heat absorption in the convective section of the boiler due to the sootblowing

co-firing tests, in anticipation of increase fouling. This was within the normal boiler operating envelope and the increase in the steam consumption for the

Slagging/fouling and corrosion

The inorganic constituents of biomass materials, and the ashes produced in combustion and other thermal processes, are of particular interest for plant designers and operators. These

in a number of important respects from coal ashes. They are not silicate systems, and commonly comprise mixtures of a limited number of relatively

simple inorganic compounds, principally silica, and the oxides, sulphates, chlorides and f the alkali and the alkaline earth metals. In general terms, therefore, the

biomass ashes are relatively rich in elements that are effective fluxes for coal ash systems and that tend to be volatile at elevated temperatures in combustion and o

The overall result is that many of the potential impacts of the co-firing of biomass materials in coal combustion and other thermal processing plants are associated with the changes in the ash composition and the ash behaviour that occur when co-firing. The principal ashimpacts on plant operation and integrity that may be affected by biomass co

The formation of fused or partly-fused ash deposits on surfaces in furnaces and

The formation of bonded ash deposits on convective section heat exchangers;The formation of aggressive ash deposits on high temperature surfaces, resultiaccelerated metal wastage; The formation of aggressive ash deposits on surfaces at saturated steam temperature, resulting in accelerated metal wastage in the area from the burner to the first convective heat exchangers; The formation and emission of fine inorganic aerosols and fumes; The impact on the performance of flue gas cleaning equipment; The impact on the handling and the utilisation/disposal of the ash discards from

These impacts are dependent on a number of factors, including the chemistry and behaviour of the coal and the biomass ashes, the co-firing ratio and the plant configuration. The ability

ssess these risks and to minimise the impacts on plant performance are of key

The industry has a suite of laboratory test procedures and other methods for the analysis and characterisation of coal ashes, and these have been applied, with appropriate modification where necessary, to biomass ashes and the ashes from co-firing.

To date, the industrial experience has been principally with the co-firing of clean biomass materials in large pulverised coal boilers at relatively low co-firing ratios. Currently, however, the range of biomass materials of industrial interest is expanding rapidly, and the coratios are increasing. These trends will tend to result in an increase in the risks of significant

related impacts on the performance and integrity of the thermal processing equipment.

In all of the demonstration plants, the slagging, fouling and corrosion tendency evaluated with appropriate short-term measurement campaigns. In Fusina PP, where RDF

fired, long-term deposition and corrosion monitoD7.10

(79)

No major differences appear in the gas composition downstream of the economiser, i.e. the the normal range of fluctuation experienced

levels in the fly ashes were also unchanged when co-firing RDF.

in boiler performance were an increase in the heat sootblowing cycle frequency

tests, in anticipation of increase fouling. This was within steam consumption for the

The inorganic constituents of biomass materials, and the ashes produced in combustion and other thermal processes, are of particular interest for plant designers and operators. These

in a number of important respects from coal ashes. They are not silicate systems, and commonly comprise mixtures of a limited number of relatively

simple inorganic compounds, principally silica, and the oxides, sulphates, chlorides and f the alkali and the alkaline earth metals. In general terms, therefore, the

biomass ashes are relatively rich in elements that are effective fluxes for coal ash systems and that tend to be volatile at elevated temperatures in combustion and other thermal

firing of biomass materials in coal combustion and other thermal processing plants are associated with the changes in the

firing. The principal ash-related impacts on plant operation and integrity that may be affected by biomass co-firing include:

rfaces in furnaces and

vective section heat exchangers; The formation of aggressive ash deposits on high temperature surfaces, resulting in

The formation of aggressive ash deposits on surfaces at saturated steam accelerated metal wastage in the area from the burner to the

utilisation/disposal of the ash discards from

These impacts are dependent on a number of factors, including the chemistry and behaviour firing ratio and the plant configuration. The ability

ssess these risks and to minimise the impacts on plant performance are of key

The industry has a suite of laboratory test procedures and other methods for the analysis and ied, with appropriate modification

firing of clean biomass iring ratios. Currently, however,

the range of biomass materials of industrial interest is expanding rapidly, and the co-firing ratios are increasing. These trends will tend to result in an increase in the risks of significant

rformance and integrity of the thermal processing equipment.

tendency has been In Fusina PP, where RDF

corrosion monitoring campaigns



Date: 15.03.2013

were carried out. The evidence from Fusina indicated that there was a long term trend towards higher levels of slag formation on furnace surfacecompared to coal firing alone.

No significant influence of cardoonobserved on the slagging behaviourin the slagging and fouling in the combustion chamber as well as at the convective part inletis anticipated.

In summary, the experience with waste to energy plants and biomass power plantsindicated that the following measures against boiler corrosion may be

- The online-cleaning of tubes and membrane walls can reduce the risk of circular reactions underneath the deposits

- The introduction of curtain air at the furnace walls may help to maintain oxidising conditions at the furnace walls can help to cont

- The testing results suggest that the reduction is a complex matter. application of pyrogenic silica. The application of SOsimilar to the so called “Chlor

3.5 Air pollution control

The impact of biomass and RDF coDevices (APCDs) was assessedby the performance analysis of the selective catalytic reduction (SCR) unit and of the electrostatic precipitator.

The future legal requirements of the Industrial Emission Directive (IED 2010/75/EU (12)) are listed Tablerespectively.

Demonstrations showed that for biomass coCombustion Plants (LCP) originally designed for PC a fmeet the emission limits. That means DeNOx, dethis equipment it is possible to respect the emission limits for new power plants in accordance with the Industrial Emission Direclignite, wood), in some cases the deforgetting to carefully verify the respect of the

It has been noted that without DeNOx equthe emission requirements of the IED. The values of Rodenhuize therefore before installing highvalues are far above the emission limits. combined with a high Cl-content in the fuel is able to oxidiform, which can be captured in the wet Foxidation potential can however decrease during biomass co-firing because of

With regard to the ESP, the results show that the co-firing. With high amount of biomassconcentration decreases. This indicates thatcan be used for biomass firing. It is no problem to remove µm, while finer particles (with d < 2.5 µmefficiency as for coal-firing, a wellneeded. However, the emissions of fine



The evidence from Fusina indicated that there was a long term trend towards higher levels of slag formation on furnace surfaces when cocompared to coal firing alone.

influence of cardoon/lignite co-firing at 10% biomass thermal share observed on the slagging behaviour at Kardia. At higher biomass co-firing

g and fouling in the combustion chamber as well as at the convective part inlet

, the experience with waste to energy plants and biomass power plantsthe following measures against boiler corrosion may be helpful:

cleaning of tubes and membrane walls can reduce the risk of circular reactions underneath the deposits. The introduction of curtain air at the furnace walls may help to maintain oxidising conditions at the furnace walls can help to control fireside corrosion rates.

results suggest that the application of fireside additives complex matter. Only a few tests were a little successful,

application of pyrogenic silica. The application of SO3 or SO3-forming compounds r to the so called “Chlor-out”® procedure may be more promising.

Air pollution control device performance

The impact of biomass and RDF co-firing on the performance of the Air Pollution Control Devices (APCDs) was assessed during long term monitoring of emission values as well as by the performance analysis of the selective catalytic reduction (SCR) unit and of the

The future legal requirements of the Industrial Emission Directive (IED Table 10 and Table 11 for new and for existing power plants

Demonstrations showed that for biomass co-firing or 100% biomass combustion in Large Combustion Plants (LCP) originally designed for PC a flue gas cleaning system is needed to meet the emission limits. That means DeNOx, de-dusting and de-sulphurization steps. With this equipment it is possible to respect the emission limits for new power plants in accordance with the Industrial Emission Directive. Depending on the fuel constituents (e.g lignite, wood), in some cases the de-sulphurisation step can be omitted, of course without forgetting to carefully verify the respect of the heavy metal emission limits.

without DeNOx equipment (Kardia PP) there is no chance to of the IED. The values of Rodenhuize PP before retrofitting

installing high-dust catalyst, show that without DeNOx equipment the NOxmission limits. It could be shown that a high

content in the fuel is able to oxidise elemental mercury to the ionic which can be captured in the wet Flue Gas Desulphurisation (FGD) system

can however decrease with deactivation of the catalystbecause of the higher amount of alkali salts in the fly ash.

he results show that the dust particle size distribution changefiring. With high amount of biomass, the amount of fine particles increases

concentration decreases. This indicates that, if the ESP is well designed for coalcan be used for biomass firing. It is no problem to remove fine particles with d 2.5 < d < 10

with d < 2.5 µm) can pass the ESP. To have the same dust removal a well-designed ESP or a combination of ESP and wet FGD is

needed. However, the emissions of fine dust < PM 2.5 cannot be prevented.

D7.10

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The evidence from Fusina indicated that there was a long term trend s when co-firing the RDF

thermal share has been levels, an increase

g and fouling in the combustion chamber as well as at the convective part inlet

, the experience with waste to energy plants and biomass power plants has helpful:

cleaning of tubes and membrane walls can reduce the risk of circular

The introduction of curtain air at the furnace walls may help to maintain oxidising rol fireside corrosion rates.

additives for corrosion Only a few tests were a little successful, e.g with the

forming compounds may be more promising.

firing on the performance of the Air Pollution Control during long term monitoring of emission values as well as

by the performance analysis of the selective catalytic reduction (SCR) unit and of the

The future legal requirements of the Industrial Emission Directive (IED – Directive for new and for existing power plants

firing or 100% biomass combustion in Large lue gas cleaning system is needed to

sulphurization steps. With this equipment it is possible to respect the emission limits for new power plants in

tive. Depending on the fuel constituents (e.g sulphurisation step can be omitted, of course without

limits.

) there is no chance to satisfy before retrofitting, and

show that without DeNOx equipment the NOx-It could be shown that a high-dust SCR device

e elemental mercury to the ionic esulphurisation (FGD) system. This

with deactivation of the catalyst, which is faster the higher amount of alkali salts in the fly ash.

particle size distribution changes with the amount of fine particles increases and the dust

if the ESP is well designed for coal-firing, it also fine particles with d 2.5 < d < 10

To have the same dust removal designed ESP or a combination of ESP and wet FGD is

2.5 cannot be prevented.



Date: 15.03.2013

PC/RDF co-firing up to 5% RDF thermal input resulted not to affect the macromicro-pollutant emissions of the PC power plant. The measurement highlighted values fairly below the maximum lawful limits.

Table 10: Emission limits of IED for new power plants with permit after 07.01.2013. Emission limits are given as monthly average values and for co

mg/Nm³ @ 6% O2

Compound Thermal input (MW)

SO2 50 - <100

100 - 300

>300

NOx 50 - <100

100 - 300

>300

Dust <50

50 - <100

100 - 300

>300

CO

Cd, Tl

Hg

Sb+As+Pb+ Cr+Co+Cu+ Mn+Ni+V

Dioxins+Furans

3) Fluidised bed firing 5) Value for waste incineration daily average6) Average values over the sampling period of a minimum of 30 minutes and a maximum of 8 hours7) ng/Nm³, average value measured over the sampling period of a minimum of 6 hours and a maximum of 8 hours



firing up to 5% RDF thermal input resulted not to affect the macropollutant emissions of the PC power plant. The measurement highlighted values fairly

limits.

Emission limits of IED for new power plants with permit after 07.01.2013. Emission limits are given as monthly average values and for co-firing as daily average in mg/Nm³ @ 6% O

IED emission limits for new plants

1)Coal, 2)Lignite Biomass Coal-Waste

co-firing

400 200 400

200 200 200/2503)

150/2003) 150/2003) 150/2003)

3001)/4002) 250 300

200 200 200

150/2002) 150 150/2002)

50

20 20 20

20 20 20

10 20 10

505)

0.056)

0.056)

0.56)

0.17)

Value for waste incineration daily average verage values over the sampling period of a minimum of 30 minutes and a maximum of 8 hours

ng/Nm³, average value measured over the sampling period of a minimum of 6 hours and a maximum of 8 hours

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firing up to 5% RDF thermal input resulted not to affect the macro-pollutant and pollutant emissions of the PC power plant. The measurement highlighted values fairly

Emission limits of IED for new power plants with permit after 07.01.2013. Emission limits firing as daily average in mg/Nm³ @ 6% O2.

plants

Waste

Biomass-Waste co-firing

200

200

150

250

200

150

50

20

20

20

505)

0.056)

0.056)

0.56)

0.17)




Date: 15.03.2013

Table 11: Emission limits of IED for existing power plants and power plants with permit before 27.11.2002. Emission limits are given as monthly average values and for co

mg/Nm³ @ 6% O2

Compound Thermal input (MW)

SO2 50 - <100

100 - 300

>300

NOx 50 - <100

100 - 300

>300

Dust <50

50 - <100

100 - 300

>300

CO

Cd, Tl

Hg

Sb+As+Pb+ Cr+Co+Cu+ Mn+Ni+V

Dioxins+ Furans

3) Fluidized bed firing 5) Value for waste incineration daily average6) average values over the sampling period7) ng/Nm³, average value measured over the sampling period of a minimum of 6 hours and a maximum of 8 hours

3.6 Ash utilisation

The utilisation of CCPs from coaltechnical, physical and chemical properties of the ashes are addressed in product and application standards and regulationdemonstrated that the solid bylow co-firing ratios can also be utilised as construction materials.

The co-firing of specific biomass materials is already covered by the European Standard EN 450-1 for fly ash for concrete. The biomass properties and the coguarantee that the key properties of the fly ash materials do not change significantly.



Emission limits of IED for existing power plants and power plants with permit before limits are given as monthly average values and for co-firing as daily average in

mg/Nm³ @ 6% O2.

IED emission limits for existing plants

1)Coal, 2)Lignite Biomass Coal-Waste

co-firing

400 200 400

250 200 200

200 200 200

3001)/4502) 300 3001)/4002)

200 250 200

200 200 200

30 30 30

25 20 25

20 20 20

505)

0.056)

0.056)

0.56)

0.17)

Value for waste incineration daily average average values over the sampling period of a minimum of 30 minutes and a maximum of 8 hours ng/Nm³, average value measured over the sampling period of a minimum of 6 hours and a maximum of 8 hours

of CCPs from coal-fired power plants has developed over decades. The basic technical, physical and chemical properties of the ashes are addressed in product and application standards and regulations. In general terms, the DEBCO p

at the solid by-products generated during the co-firing in dedicated plants at firing ratios can also be utilised as construction materials.

firing of specific biomass materials is already covered by the European Standard EN for concrete. The biomass properties and the co-firing levels are limited to

guarantee that the key properties of the fly ash materials do not change significantly.

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Emission limits of IED for existing power plants and power plants with permit before firing as daily average in

IED emission limits for existing plants

Waste

Biomass-Waste co-firing

200

200

200

2) 300

250

200

50

30

20

20

505)

0.056)

0.056)

0.56)

0.17)


fired power plants has developed over decades. The basic technical, physical and chemical properties of the ashes are addressed in product and

s. In general terms, the DEBCO project has firing in dedicated plants at

firing of specific biomass materials is already covered by the European Standard EN firing levels are limited to

guarantee that the key properties of the fly ash materials do not change significantly.



Date: 15.03.2013

In order to extend the co-firing of biomass to higher levels, the utilisation paths of byneed to be analysed and the impact of cominimise the quantities of material that need to be sent to disposal to land.

For the use in or as construction materials, the requirements in European standhave to be considered for the placing on the market of coal ash, as well as national standards, for the application in the countries, have to be considered. CCPs could be:

- In cement; - In concrete; - Road constructions; - Aggregates.

The specific technical and other restablished by European standards

The requirements for fly ash for the use as a constituent of blended cements and of concrete established in the European Standards are given inadditional physical parameters are defined in EN

For the evaluation of the impact of coof ashes it is recommended to consider the following issues:

- If the ash from co-firing is to be used for the same purpose as impact on the chemical and physical prope

- Different biomass materials have impacts on the chemical coor lignite. The results of the work carried out within the DEBCO project svariability in the ash chemistry

- The lower the ash content of the coash. For wood pellets, the ash

- If the ash from co-firing is chemical requirements may have to be met, and this may have an impact on the biomass specification or the co-firing ratio. In general, terms, it is normally desirable to minimise the UBC levels for most applications.



firing of biomass to higher levels, the utilisation paths of byneed to be analysed and the impact of co-firing need to be assessed. The intention is to minimise the quantities of material that need to be sent to disposal to land.

For the use in or as construction materials, the requirements in European standhave to be considered for the placing on the market of coal ash, as well as national standards, for the application in the countries, have to be considered. The possible uses of

The specific technical and other requirements for fly ashes for different applications established by European standards, and these are listed in Table 12.

The requirements for fly ash for the use as a constituent of blended cements and of concrete established in the European Standards are given in Table 13. For the use in concrete, some additional physical parameters are defined in EN 450-1:2005 and listed in

For the evaluation of the impact of co-firing of different biomass / materials on the properties s it is recommended to consider the following issues:

is to be used for the same purpose as the ash from coalimpact on the chemical and physical properties should be minimal or negligible

materials have different chemical compositions and will have different the chemical compositions of the ashes resulting from co-firing with hard coal

of the work carried out within the DEBCO project svariability in the ash chemistry even when co-firing relatively well-defined wood pellets.

the ash content of the co-firing material, the lower the impact on the resulting the ash content is commonly less than 2.5% by mass

firing is to be used for specific fields of application, may have to be met, and this may have an impact on the biomass

firing ratio. In general, terms, it is normally desirable to minimise the levels for most applications.

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firing of biomass to higher levels, the utilisation paths of by-products firing need to be assessed. The intention is to

minimise the quantities of material that need to be sent to disposal to land.

For the use in or as construction materials, the requirements in European standards, which have to be considered for the placing on the market of coal ash, as well as national

The possible uses of

for different applications are

The requirements for fly ash for the use as a constituent of blended cements and of concrete For the use in concrete, some

Table 14.

firing of different biomass / materials on the properties

the ash from coal, the rties should be minimal or negligible.

different chemical compositions and will have different firing with hard coal

of the work carried out within the DEBCO project show significant defined wood pellets.

the lower the impact on the resulting % by mass.

, special physical or may have to be met, and this may have an impact on the biomass

firing ratio. In general, terms, it is normally desirable to minimise the



Date: 15.03.2013

Table 12 :

In cement EN 197-1 common cements”(For the definition of fly ash refers to EN 450

In concrete EN 450 “Fly ash for concrete” EN 450-1 criteria” EN 450-2

Road constructions DIN EN 14227

treated by hydraulic road binder”DIN EN 14227mixtures” DIN EN 14227hydraulically bound mixtures” prEN 13282criteria” prEN 13282binders - Composition, specifications and conformity criteria” prEN 13282binders - Composition, specifications and conformity criteria”

Aggregates EN 12620(for lightweight aggregates for concrete, mortar and grout:EN 13055



: European standards for fly ash requirements.

“Cement – Part 1: Composition, specifications and conformity criteria for common cements” For the definition of fly ash - and therefore also regarding co-

EN 450-1)

“Fly ash for concrete” “Fly ash for concrete – Part 1: Definition, specifications and conformity

“Fly ash for concrete – Part 2: Conformity evaluation”

DIN EN 14227-13 “Hydraulically bound mixtures - Specifications treated by hydraulic road binder” DIN EN 14227-3 “Hydraulically bound mixtures - Specifications: Fly ash bound

DIN EN 14227-4 “Hydraulically bound mixtures - Specifications: Fly ash for hydraulically bound mixtures” prEN 13282 “Hydraulic road binders – Composition, specifications and conformity

prEN 13282-1 “Hydraulic road binders - Part 1: Rapid hardening hydraulic rComposition, specifications and conformity criteria”

prEN 13282-2 “Hydraulic road binders - Part 2 : Normal hardening hydraulic road Composition, specifications and conformity criteria”

EN 12620 “Aggregates for concrete” (for lightweight aggregates for concrete, mortar and grout: EN 13055-1 “Lightweight aggregates for concrete, mortar and grout”)

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Part 1: Composition, specifications and conformity criteria for

-firing - the standard

Part 1: Definition, specifications and conformity

Specifications - Part 13: Soil

Specifications: Fly ash bound

Specifications: Fly ash for

Composition, specifications and conformity

Part 1: Rapid hardening hydraulic road

Part 2 : Normal hardening hydraulic road

“Lightweight aggregates for concrete, mortar and grout”)



Date: 15.03.2013

Table 13 : Requirements on fly ash for use in cement and in concrete.

siliceous fly

Loss on ignition1)

Chloride

Sulphuric anhydrite (SO3)

Reactive calcium oxide2)

Free calcium oxide ≤ 1% by mass

Reactive silicon dioxide4)

Silicon dioxide, aluminium and iron oxide

Alkalis (Na2Oequivalent)

Magnesium oxide

Soluble phosphate

Compressive strength at 28d5)

Expansion6)

1) LOI of up to 7 or 9 % by mass is allowed provided requirements at the place of use regarding durability are met2) CaOreactiv = total CaO reduced by fraction calculated as CaCO3) CaOfree-= amount up to 2.5% by mass accepted when soundness is given (see 4) SiO2reactiv = fraction of SiO2 which is soluble after treatment with HCl and boiling KOH5) mortars with ground fly ash as binder, 6) mixture of 30 % by mass ground fly ash, 707)if the amount of free calcium oxide exceed 1.0% by mass soundness have to be proven8)requirement to be fulfilled for fly ash obtained from co



: Requirements on fly ash for use in cement and in concrete.

Use in cement EN 197-1 Use in concrete EN 450

siliceous fly ash calcareous fly ash

V W1 W2

category A: ≤ 5.0% by mass ≤

category B: 2 - 7% by mass 2

category C: 4 - 9% by mass 4

- - - ≤

- - - ≤

≤ 10% by mass

10 – 15% by mass ≥ 15% by mass ≤

1% by mass 3)

≤

≥ 25% by mass - ≥

- - - amount of SiO

Fe2O

- - - ≤ 5.0

- - - ≤ 4.0

- - -

- - ≥ 10 N/mm²

- - ≤ 10 mm

LOI of up to 7 or 9 % by mass is allowed provided requirements at the place of use regarding durability are met

= total CaO reduced by fraction calculated as CaCO3 and CaSO4

% by mass accepted when soundness is given (see 5))

which is soluble after treatment with HCl and boiling KOH-solution

mortars with ground fly ash as binder, amount < 40µm between 10 and 30% by mass

ash, 70% by mass cement if the amount of free calcium oxide exceed 1.0% by mass soundness have to be proven

requirement to be fulfilled for fly ash obtained from co-combustion

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: Requirements on fly ash for use in cement and in concrete.

in concrete EN 450 -1

fly ash

≤ 5.0% by mass

2 - 7% by mass

4 - 9% by mass

≤ 0.1% by mass

≤ 3.0% by mass

≤ 10% by mass

2.5% by mass 7)

≥ 25% by mass 8)

amount of SiO2, Al2O3, O3 ≥ 70% by mass 8)

5.0% by mass (as Na2Oeq)

8)

4.0% by mass (as Na2Oeq)

8)

≤ 100 mg/kg8)

-

-

LOI of up to 7 or 9 % by mass is allowed provided requirements at the place of use regarding durability are met



Date: 15.03.2013

Table 14: Physical requirements for fly ash

fineness (residue on 45 µm mesh sieve) fineness variations 1) (deviation from declared value)

density variation

soundness2)

activity index4) after 28 days after 90 days

initial setting time

water demand

1) average value as declared by the producer2) required only if amount of CaOfree is > 1% by mass3) to be determined with a paste made from 30% by mass of fly ash and 70% by mass of cement4) to be determined with a paste made from 25% by mass of fly ash and 75% by mass of cement5) requirement is assumed to be met for fly ash produced by combustion of pure co

3.6.1 Rodenhuize

At Rodenhuize PP the amount of (Advanced Green) and later 100% wood pelletthe type fired at Rodenhuize have depending on the level of bark present. The wood pellets have much lower ash contents than most coals and, as a consequence, the coimpact on the chemistry of the mixed ash produced.levels in the ashes can be controlled by the maintenance of acceptable combustion conditions. The industry has already agreed on a qualityto maintain adequate control over the ash levels in the wood fuels. These standards will normally permit the ash quality standards for the products of the comet under normal combustion conditions.

At present, the standard for fly ash for concrete EN 450firing to 20% by mass. However, due to the experience with cothe level of co-firing will be increased to wood. The results of the ash tests with this revision of the standard.

3.6.2 Rodenhuize

With 100% wood pellet combustionoriginating from coal combustion and from comagnesium oxide, alkali metals, iron oxide are lower, as would be econstituent of cement, it will be the task of the cement producer to decide about the ratio of this ash in his raw meal mix.



Physical requirements for fly ash in accordance with EN 450

category N: ≤ 40% by masscategory S: ≤ 12% by mass,

category N: ≤ ± 10% by mass

category S: - (note: the ± 10 % percentage points are not applicable)

1) ± 200 kg/m³

max. 10 mm (30/70)3)

≥ 75% ≥ 85%

≤ 120 min more than cement paste with test cement 4)5)

category N: not valid category S: ≤ 95% of that for the

test cement alone

average value as declared by the producer required only if amount of CaOfree is > 1% by mass

determined with a paste made from 30% by mass of fly ash and 70% by mass of cementto be determined with a paste made from 25% by mass of fly ash and 75% by mass of cementrequirement is assumed to be met for fly ash produced by combustion of pure coal

Rodenhuize - co-firing of wood pellets

the amount of wood pellet co-firing was increased from 25 to 50% 100% wood pellet was fuelled (Max Green). W

the type fired at Rodenhuize have a fairly wide range of chemical compositions, normally depending on the level of bark present. The wood pellets have much lower ash contents than most coals and, as a consequence, the co-firing of wood pellets normally has only a modest

ry of the mixed ash produced. In most systems, the control of the levels in the ashes can be controlled by the maintenance of acceptable combustion

he industry has already agreed on a quality scheme for wood pellets whichadequate control over the ash levels in the wood fuels. These standards will

normally permit the ash quality standards for the products of the co-firing of these fuels to be met under normal combustion conditions.

At present, the standard for fly ash for concrete EN 450-1 (13) restricts the amount of cofiring to 20% by mass. However, due to the experience with co-firing over the

will be increased to 40% by mass, and 50% by mass in case of green of the ash tests for wood pellets co-firing within DEBCO are consistent

with this revision of the standard.

Rodenhuize - combustion of 100% wood pellet

With 100% wood pellet combustion, the ash residues differ significantly from those originating from coal combustion and from co-firing. The ashes are rich in

metals, phosphate and sulphur. The levels of silica, alumina and , as would be expected for wood ash. For utilisation of this material as a

t will be the task of the cement producer to decide about the ratio of

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EN 450-1.

40% by mass 12% by mass,

10% by mass

10 % percentage points are not applicable)

120 min more than cement paste with test cement 4)5)

95% of that for the

determined with a paste made from 30% by mass of fly ash and 70% by mass of cement to be determined with a paste made from 25% by mass of fly ash and 75% by mass of cement

al

was increased from 25 to 50% Wood pellet fuels of

compositions, normally depending on the level of bark present. The wood pellets have much lower ash contents than

firing of wood pellets normally has only a modest In most systems, the control of the UBC

levels in the ashes can be controlled by the maintenance of acceptable combustion scheme for wood pellets which help

adequate control over the ash levels in the wood fuels. These standards will firing of these fuels to be

restricts the amount of co-firing over the past few years,

and 50% by mass in case of green within DEBCO are consistent

combustion of 100% wood pellets

differ significantly from those are rich in calcium- and

levels of silica, alumina and xpected for wood ash. For utilisation of this material as a




Date: 15.03.2013

The ash may be used as a lime or an alkali agent. considered. These applications may be need to be considered for a specific country or region and regional requirements.

3.6.3 Fusina

At Fusina PP the co-firing of refuse derived fuel (RDF) At these co-firing levels, the ranges of the concentrations of the main ash constituents are similar to those for coal ashes. RDF materials, howco-firing materials in EN 450-1.

The ash would require special consideration if it were to be The RDF used for the co-firing trials had a biomass fraction of more than 60% by massan ash content of about 15 to 22% by mass.

Compared with pure bituminous coal combustion, t5% RDF co-firing showed a slight increase inFe, Zn), alkalis and chlorides.the future requirements for the application rules.

The main conclusion of the fly ash characteriinput has slightly increased tcomposition and, therefore, the use as concr(European Technical Approval)

3.6.4 Kardia

At Kardia PP, co-firing was tested plant is lignite from nearby lignite mines. relatively wide range for the ash biomass used for the tests is characterised by an ash content ranging frommass. The impact of co-firing firing of the biomass resultednormal lignite fuel diet.

As the investigated ashes from lignite are not covered in the fly ash standard for concrete and as the chemical composition of these ashes is material, as e.g. filling material, the physical properties have to be considered more intensively as well as the trace element concentrationIf the co-firing is combined with cement and concrete may be



The ash may be used as a lime or an alkali agent. and its use as a low grade applications may be restricted by trace elements contents, and these

need to be considered for a specific country or region and for the respective nationa

Fusina - co-firing of RDF

firing of refuse derived fuel (RDF) up to 5% (thermal) was investigatfiring levels, the ranges of the concentrations of the main ash constituents are

es. RDF materials, however, are not covered by the definition of 1.

require special consideration if it were to be used as an addition for concrete. firing trials had a biomass fraction of more than 60% by mass

ent of about 15 to 22% by mass.

Compared with pure bituminous coal combustion, the analyses of the ashes sampled duringa slight increase in the concentrations of same trace elements

s. The trace elements need to be taken into accountthe product standards as well as in light of the

conclusion of the fly ash characterisation is that RDF co-firing up toinput has slightly increased the trace element contents but not affected

the use as concrete addition could be possible provided aEuropean Technical Approval) for co-firing of RDF is granted.

Kardia - co-firing of cardoon biomass

was tested up to 10% cardoon thermal share. The main fuel is lignite from nearby lignite mines. A number of different lignite types are fired and

the ash chemical parameters have to be considered.biomass used for the tests is characterised by an ash content ranging from

firing on the ash quality was modest and, in general terms, ed in a more consistent ash chemical composition than for the

As the investigated ashes from lignite are not covered in the fly ash standard for concrete and as the chemical composition of these ashes is varying widely for a use as construction material, as e.g. filling material, the physical properties have to be considered more intensively as well as the trace element concentration, especially for the leaching limit values.

ith lignite from a specific seam, also ash qualities for the use in cement and concrete may be obtained.

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and its use as a low grade fertiliser can be contents, and these

the respective national and/or

5% (thermal) was investigated. firing levels, the ranges of the concentrations of the main ash constituents are

not covered by the definition of

used as an addition for concrete. firing trials had a biomass fraction of more than 60% by mass, and

the ashes sampled during the concentrations of same trace elements (Cu,

elements need to be taken into account in light of the existing national

firing up to 5% thermal contents but not affected the main oxide

ete addition could be possible provided an ETA

. The main fuel of the A number of different lignite types are fired and a

to be considered. The cardoon biomass used for the tests is characterised by an ash content ranging from 9.5 to 14.5% by

modest and, in general terms, the co-chemical composition than for the

As the investigated ashes from lignite are not covered in the fly ash standard for concrete varying widely for a use as construction

material, as e.g. filling material, the physical properties have to be considered more leaching limit values.

ash qualities for the use in



Date: 15.03.2013

4 Conclusions The DEBCO project has involved andemonstration work aimed at the further materials with coal as a mean for using renewable f(DEmonstration of large scale Biomass COcollaborative RTD project included in the seventeen Partners from eight different EU Countries.

The general objectives of the research activities, large-scale demonstrations and longoptions.

This Guidebook is intended to provide a summary of DEBCO project with a particular focus on:

- The economical aspectsstructure, the local and which may affect co-firing projects;

- The technical aspects, including the fuel characteristics and storage/handling requirements, the plant modifications required for cocontrol device performance, the utilisation/disposal of the ash and other discards from the power plants.

The co-firing of biomass in coal boilers is generation. Different government subsidyprovide a range of national incentives for biomass co

The key advantages of biomass co

- the utilisation of existing capital equipment, with modest costs andtimes for plant conversion;

- the biomass fuel flexibility, parti- the relatively high overall power generation efficiencies from biomass.

The main technical results illustrated in the present Guidebook configurations employing different shares

The analysis of the member state potential of biomass co-firing is not European countries. A common approachsustainability criteria, would lead to apropensity for the private sector

The analysis of the market potential showthe European and international market for solid biomass fuelswith food supply, wood process industrystimulation of local markets for biomass fuelsector, and create new jobs in the agricultural

Biomass and RDF co-firing, at low and high levels, face somcompatibility and logistics, boiler efficiency, environmental control,

The impacts of biomass/RDF codepend on the share of biomassare modest and, in many cases with clean biomass materials, the impacts are negligible. At higher co-firing levels, the impacts are more significant, and it may be necessary to limit the range of fuels fired, modify the existing equi




with coal as a mean for using renewable fuels in the near term. DEBCO (DEmonstration of large scale Biomass CO-firing and supply chain Integration) is a

project included in the EC framework program FP7seventeen Partners from eight different EU Countries.

the DEBCO project have been achieved through a program scale demonstrations and long-term monitoring of the key co

intended to provide a summary of the key results and experiences roject with a particular focus on:

conomical aspects, including the political and regulatory framework, the market structure, the local and international fuel supply chains and the main economic factors

firing projects; The technical aspects, including the fuel characteristics and storage/handling requirements, the plant modifications required for co-firing, the boiler and control device performance, the utilisation/disposal of the ash and other discards from

coal boilers is an important technology for CODifferent government subsidy schemes, as well as other financial instruments

national incentives for biomass co-firing within the European Union.

advantages of biomass co-firing include:

ation of existing capital equipment, with modest costs andtimes for plant conversion; the biomass fuel flexibility, particularly at low co-firing ratios; the relatively high overall power generation efficiencies from biomass.

technical results illustrated in the present Guidebook are based on six coonfigurations employing different shares of biomass firing and different fuels

the member state policy framework shows that the economic and ecological firing is not adequately recognised in the legislation of

European countries. A common approach across Europe, at least for incentives and binding sustainability criteria, would lead to an improved level of security for investment,

for the private sector to invest.

The analysis of the market potential shows clearly that there is significant the European and international market for solid biomass fuels, without significant interference

, wood process industry or land use issues. It is also considered that thestimulation of local markets for biomass fuels will help secure employment in the power

and create new jobs in the agricultural and transport sectors.

firing, at low and high levels, face some technical issues such as fuel boiler efficiency, environmental control, ash quality and utilisation

The impacts of biomass/RDF co-firing on the performance and integrity of the installed plant depend on the share of biomass or RDF co-fired. At up to 5-10% thermal input, the impacts are modest and, in many cases with clean biomass materials, the impacts are negligible. At

firing levels, the impacts are more significant, and it may be necessary to limit the fuels fired, modify the existing equipment or install new equipment.

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uels in the near term. DEBCO hain Integration) is a

rk program FP7, and involves

roject have been achieved through a program of term monitoring of the key co-firing

results and experiences of the

, including the political and regulatory framework, the market international fuel supply chains and the main economic factors



an important technology for CO2-neutral electricity as well as other financial instruments, firing within the European Union.

ation of existing capital equipment, with modest costs and fairly short project

the relatively high overall power generation efficiencies from biomass.

are based on six co-firing fuels.

economic and ecological in the legislation of all of the

, at least for incentives and binding for investment, and a higher

significant potential growth in significant interference

It is also considered that the secure employment in the power

issues such as fuel ash quality and utilisation.

firing on the performance and integrity of the installed plant 10% thermal input, the impacts

are modest and, in many cases with clean biomass materials, the impacts are negligible. At firing levels, the impacts are more significant, and it may be necessary to limit the

pment or install new equipment.



Date: 15.03.2013

The main conclusions from the demonstration activities carried out under the DEBCO project are:

- The maintenance of a high level of control of the quality and composition of the delivered fuel is essential for the power plantare required for large scale bi

- The long-term storage and the handling of large amounts of biomass fuel presents a number of significant new challenges to the to plant safety, and biomass storage

- The co-firing ratio and the mode of introduction coal boiler have a influence boiler. It is normally necessary to modify plant operations to permit comay be necessary to modify the installed equipment to accommodate the new fuel mix.

- The experience of the PC power plant operationthat capital-expensive boiler modifications are low biomass or RDF levels as at including modification of fuel handling feeding and firing sybe required for higher co

- For biomass co-firing and 100% biomass combustion in necessary to have a flue gas cleaning system that meets the requirements for best available technology (BAT). Thsulphurisation equipment.limits for new power plants according to the Industrial Emission Directive. Depending on the fuel constituents

- The utilisation of the ashes resulting from copower plants can be achieved in some cases, however the fuels and that of the specific mix of codetail.



The main conclusions from the demonstration activities carried out under the DEBCO project

The maintenance of a high level of control of the quality and composition of the fuel is essential for the power plant operation, and binding quality standards

are required for large scale biomass utilisation; term storage and the handling of large amounts of biomass fuel presents a

number of significant new challenges to the power plant operators, particularly related and biomass storage conveying, milling and feeding;

firing ratio and the mode of introduction of the biomass influence on the performance of the combustion

It is normally necessary to modify plant operations to permit comay be necessary to modify the installed equipment to accommodate the new fuel

the PC power plant operation gained during the project indicates expensive boiler modifications are generally not required

levels as at Fusina and Kardia. More significant modificationsmodification of fuel handling feeding and firing system and of the boiler may

be required for higher co-firing levels as at Rodenhuize PP. firing and 100% biomass combustion in large combustion

necessary to have a flue gas cleaning system that meets the requirements for best available technology (BAT). This normally involves a NOx control,

equipment. With suitable equipment it is possible to meet the emissilimits for new power plants according to the Industrial Emission Directive. Depending on the fuel constituents it may be possible to, operate without de-sulphuri

ashes resulting from co-firing of different materials in coalcan be achieved in some cases, however the chemical composition of

the fuels and that of the specific mix of co-firing material have to be considered

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The main conclusions from the demonstration activities carried out under the DEBCO project

The maintenance of a high level of control of the quality and composition of the operation, and binding quality standards

term storage and the handling of large amounts of biomass fuel presents a , particularly related

ing, milling and feeding; the biomass into the pulverised

ustion system and the It is normally necessary to modify plant operations to permit co-firing, and it

may be necessary to modify the installed equipment to accommodate the new fuel

ng the project indicates required for co-firing at

More significant modifications stem and of the boiler may

ombustion plants, it is necessary to have a flue gas cleaning system that meets the requirements for best

control, de-dusting and de-equipment it is possible to meet the emission

limits for new power plants according to the Industrial Emission Directive. Depending sulphurisation.

firing of different materials in coal-fired the chemical composition of

firing material have to be considered in



Date: 15.03.2013

5 References (1) DEBCO website (http://www.debco.eu

for future implementation of fuel supply c (2) Initiative of Wood Pellet Buyers (IWPB),

pellet-buyers-iwpb/ (Accessed 14.01.

(3) EURELECTRIC, “Sustainability Criteria for Solid & Gaseous Biomass EC COM(2010)11 final

(4) http://www.greengoldcertified.org/

(5) Vereinbarung zwischen dem Land Berlin und der Vattenfall Europe AG über Kriterien zur Nachhaltigkeit der Beschaffung von holz

(6) http://www.apxendex.com/market

(7) http://www.bioenergytrade.org/downloads/t40study_final.pdf

(8) http://www.pellet.org/home/24

(9) M. Born, “Cause and Risk Evaluation for HighPowerTech 5, 2005

(10) VGB Powertech e.V., VGB

(11) VGB Powertech e.V., “Fire and Explosion Protection in Biomass Essen, expected in 2012

(12) “Industrial Emission Directive (IED): Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated polprevention and control)”

(13) “EN 450-1: Fly ash for concrete criteria”, 2005 + A1 2007

(14) Italian Ministry for the Economic Development, Ministerial Decree 06.07.2012

(15) IEA Report: “Health and Safety Aspects of Solid Biomass Storage, Transportation and Feeding”, 2013

(16) “The Pellet Handbook”, Ingwald Obernberger, Gerold Thek, Earthscan, 2010



http://www.debco.eu), Deliverable D3.6 “Indicators and guidelines for future implementation of fuel supply chains”

of Wood Pellet Buyers (IWPB), http://www.laborelec.be/ENG/initiative(Accessed 14.01.2013)

EURELECTRIC, “Sustainability Criteria for Solid & Gaseous Biomass final”, May 2010

http://www.greengoldcertified.org/

Vereinbarung zwischen dem Land Berlin und der Vattenfall Europe AG über Kriterien Nachhaltigkeit der Beschaffung von holzartiger Biomasse,” Berlin, 2009

http://www.apxendex.com/market-results/futures-markets/endex-wood

http://www.bioenergytrade.org/downloads/t40-global-wood-pellet-market

http://www.pellet.org/home/24-italys-increasing-demand

M. Born, “Cause and Risk Evaluation for High-temperature Chlorine Corrosion,”

VGB Powertech e.V., VGB-R 108: Fire Protection in Power Plants, Essen, 2009

VGB Powertech e.V., “Fire and Explosion Protection in Biomass FEssen, expected in 2012

“Industrial Emission Directive (IED): Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated polprevention and control)”

1: Fly ash for concrete – Part 1: Definitions, specifications and conformity 2005 + A1 2007

Italian Ministry for the Economic Development, Ministerial Decree 06.07.2012

IEA Report: “Health and Safety Aspects of Solid Biomass Storage, Transportation

“The Pellet Handbook”, Ingwald Obernberger, Gerold Thek, Earthscan, 2010

D7.10

(79)

D3.6 “Indicators and guidelines

http://www.laborelec.be/ENG/initiative-wood-

EURELECTRIC, “Sustainability Criteria for Solid & Gaseous Biomass - In reaction to

Vereinbarung zwischen dem Land Berlin und der Vattenfall Europe AG über Kriterien artiger Biomasse,” Berlin, 2009

wood-pellets/

market-

temperature Chlorine Corrosion,” VGB

R 108: Fire Protection in Power Plants, Essen, 2009

Fired Power Plants”,

“Industrial Emission Directive (IED): Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution

cations and conformity

Italian Ministry for the Economic Development, Ministerial Decree 06.07.2012

IEA Report: “Health and Safety Aspects of Solid Biomass Storage, Transportation

“The Pellet Handbook”, Ingwald Obernberger, Gerold Thek, Earthscan, 2010



Date: 15.03.2013

6 Appendix A – DEBCO p

6.1 Rodenhuize Power Plant

One of the key case studies on the power plant and boiler modifications for biomass cois the Rodenhuize Advanced Green and Max Green project, which involved all of the engineering and other activities specific to the co

Main information on Rodenhuize

Type: Opposed wall fired outdoor waterand gastight walls.

Make: Brouhon under Riley licence

Year of construction: 1974

Design fuel: BFG and HFO

Power: 745 MW

Conversions: 1989 converted to coal firing

2005 converted to 65 MW

2008 converted to 135 MWGreen”)

2011 converted to 560 MWGreen”)

Max Green fuel: Industrial wood pellets

The conversion of the unit 4 to 100% biomass firing was a stepwise process with a gradual increase of the biomass co-firing rate.

The biomass milling plant consists of three mor

• A buffer silo of 2,000 m³; • 4 fast rotating hammer mills of 10• Pneumatic transport system

6.1.1 Retrofitting

Biomass handling and storage

The ship unloading activities and long storage of the pellets is subcontracted to the Ghent Coal Terminal (GCT), and takes place on land adjacent to the power plant site. The pellets are unloaded by means of a Grab crane and stored in a large warehouse.

From the warehouse, the pellets are conveyed by covered belt conveyor to the day silos at the Max Green milling installation. The wood dust emissions to the environment are reduced to a minimum by means of an adequate dedischarge points.

For risk mitigation, it is recommended that the necessary preupstream of the main storage facility to avoid tramp and oversize material entering the storage.



DEBCO project power plants

Power Plant

case studies on the power plant and boiler modifications for biomass cois the Rodenhuize Advanced Green and Max Green project, which involved all of the engineering and other activities specific to the co-firing and firing of wood pellets.

Main information on Rodenhuize Unit 4:

Opposed wall fired outdoor water-tube boiler with natural circulation and gastight walls.

Brouhon under Riley licence

BFG and HFO

MWth / 285 MWel (original design)

1989 converted to coal firing

2005 converted to 65 MWel pellet co-firing with coal (“Light Green”)

2008 converted to 135 MWel pellet co-firing with coal (“Advanced

2011 converted to 560 MWth / 195 MWel 100% wood pellet firing (“Max

Industrial wood pellets

The conversion of the unit 4 to 100% biomass firing was a stepwise process with a gradual firing rate.

The biomass milling plant consists of three more or less identical systems, each comprising:

mills of 10-13.5 t/h each Pneumatic transport system for wood dust transport to the burners.

Retrofitting

Biomass handling and storage

activities and long storage of the pellets is subcontracted to the Ghent Coal Terminal (GCT), and takes place on land adjacent to the power plant site. The pellets are unloaded by means of a Grab crane and stored in a large warehouse.

he pellets are conveyed by covered belt conveyor to the day silos at the Max Green milling installation. The wood dust emissions to the environment are reduced to a minimum by means of an adequate de-dusting/extraction system (Lysair) on chutes and

For risk mitigation, it is recommended that the necessary pre-cleaning devices are installed upstream of the main storage facility to avoid tramp and oversize material entering the

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case studies on the power plant and boiler modifications for biomass co-firing is the Rodenhuize Advanced Green and Max Green project, which involved all of the

firing and firing of wood pellets.

tube boiler with natural circulation

firing with coal (“Light Green”)

firing with coal (“Advanced

100% wood pellet firing (“Max

The conversion of the unit 4 to 100% biomass firing was a stepwise process with a gradual

e or less identical systems, each comprising:

activities and long storage of the pellets is subcontracted to the Ghent Coal Terminal (GCT), and takes place on land adjacent to the power plant site. The pellets

he pellets are conveyed by covered belt conveyor to the day silos at the Max Green milling installation. The wood dust emissions to the environment are reduced

dusting/extraction system (Lysair) on chutes and

cleaning devices are installed upstream of the main storage facility to avoid tramp and oversize material entering the



Date: 15.03.2013

Main storage

For the Max Green project, pellets are stored in a large automated warehouse. Large silos could also be considered for large scale biomass storage.

The key points of attention for such facilities are:

- The installation of explosion panels to prevent the overpressure, in case of an explosion;

- CO/CO2 detection and monitoring smouldering material or

- The possibility of inertshould be considered,;

- The possibility for fast evacloaders, should be considered,

- The installation of fire det- The limitation of horizontal surfaces inside the storage where dust can settle

recommended to reduce the - The prevention of w

recommended to keep the respiration.

Figure

Day storage

The on-site day storage for the pellets consists of 3 x 2,000 m³, i.e. around 32 hours buffer storage capacity, in conic bottom, steel silos, with a rotary fuel reclaimer mounted at ground level. From the day silo, a chain conveyor transports the pellets to a small buffer silo of 50 m³ capacity located on top of the hammer mill building, from wherethe four mills. The chain conveyor has a maximum incline of 45°.



For the Max Green project, pellets are stored in a large automated warehouse. Large silos could also be considered for large scale biomass storage.

The key points of attention for such facilities are:

xplosion panels to prevent further damage to the silo by venting ressure, in case of an explosion; detection and monitoring is advised for the early detection of the presenc

smouldering material or auto-combustion in the biomass; inertion with CO2 or N2 in the case of a smouldering fire in the silo

should be considered,; ssibility for fast evacuation of the content of the silo via access doors for wheel, should be considered,

ire detection and fire fighting system is required;imitation of horizontal surfaces inside the storage where dust can settle

recommended to reduce the risk of secondary explosions; The prevention of water infiltration and the formation of condensation recommended to keep the fuel as dry as possible and minimise the risks of microbial

Figure 4: Biomass storage milling unit (1/3).

site day storage for the pellets consists of 3 x 2,000 m³, i.e. around 32 hours buffer storage capacity, in conic bottom, steel silos, with a rotary fuel reclaimer mounted at ground level. From the day silo, a chain conveyor transports the pellets to a small buffer silo of 50 m³ capacity located on top of the hammer mill building, from where the pellets are distributed to the four mills. The chain conveyor has a maximum incline of 45°.

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For the Max Green project, pellets are stored in a large automated warehouse. Large silos

further damage to the silo by venting

ly detection of the presence of

a smouldering fire in the silo

access doors for wheel

system is required; imitation of horizontal surfaces inside the storage where dust can settle is

formation of condensation is fuel as dry as possible and minimise the risks of microbial

site day storage for the pellets consists of 3 x 2,000 m³, i.e. around 32 hours buffer storage capacity, in conic bottom, steel silos, with a rotary fuel reclaimer mounted at ground level. From the day silo, a chain conveyor transports the pellets to a small buffer silo of 50 m³

the pellets are distributed to



Date: 15.03.2013

Milling

The hammer mills are located in a separate concrete building to reduce noise emissions. Each mill is located in a separate room to reduce fire propagmaintenance. The building is equipped with all necessary accessories to ensure good working and maintenance conditions.

To reduce fire and explosion risk and to increase the lifetime of the hammers, additional cleaning equipment is installed

- A vibrating screen for separation- A ferromagnetic drum - An air classifier to remove heavy particles.

The amount of UBC in the ash discards was not considered as a major consideration for Max Green, a once-through milling system, without wood dust oversize screening and rewas adopted.

For Max Green, fast rotating mills by Sprout Matador, were selected. Each mill has a nominal throughput capacity of 10 t/h. The product particle size distribution and the throughput depend the mill screen size. At Rodenhuize, a hammer mill product with a 2results in a sufficient fineness taking into account boiler impact and

Feeding

A pneumatic conveying system is used to transport the milled wood dust from the 12 hammer mills to the 24 burners of the boiler. Based on experiencesblower feeds a single pneumatic conveying pipe. Despite the higher investments costs, this solution has important advantages:

- No splitting of the biomass stream the risk of blockage,

- Good control over the dust- Constant and controllable wood

The dust/air ratio is an important parameter, which is controlled to ensure proper operation of the burners. Excessive dust/air ratios might cause pulsations and have a negthe combustion prices.

Boiler modification

Rodenhuize Unit 4 also serves as backunit located on the Arcelor-Mittal site. The boiler was retrofitted to operate on the following fuels and capacities:

- 560 MWth on BFG - 200 MWth on natural gas (- 560 MWth on biomass (

The emission requirements (at

- NOx: <60 mg/Nm³ (BAT)- SOx: <50 mg/Nm³ - Dust: <10 mg/Nm³

Light Green: Co-firing of

Advanced Green: Co-firing of pulverised wood pellets at row 2+3 (80 t/h)

Start-up fuel changed from HFO



The hammer mills are located in a separate concrete building to reduce noise emissions. Each mill is located in a separate room to reduce fire propagation and to allow separate maintenance. The building is equipped with all necessary accessories to ensure good working and maintenance conditions.

To reduce fire and explosion risk and to increase the lifetime of the hammers, additional is installed upstream of each mill:

separation of oversize material,) magnetic drum separator, and

An air classifier to remove heavy particles.

in the ash discards was not considered as a major consideration for Max through milling system, without wood dust oversize screening and re

For Max Green, fast rotating mills by Sprout Matador, were selected. Each mill has a nominal throughput capacity of 10 t/h. The product particle size distribution and the throughput depend the mill screen size. At Rodenhuize, a hammer mill product with a 2results in a sufficient fineness taking into account boiler impact and UBC amount

A pneumatic conveying system is used to transport the milled wood dust from the 12 hammer mills to the 24 burners of the boiler. Based on experiences from other projects, each blower feeds a single pneumatic conveying pipe. Despite the higher investments costs, this solution has important advantages:

ing of the biomass stream in the pneumatic conveying ducting

Good control over the dust-air ratio Constant and controllable wood dust flows.

The dust/air ratio is an important parameter, which is controlled to ensure proper operation of the burners. Excessive dust/air ratios might cause pulsations and have a neg

Rodenhuize Unit 4 also serves as back-up for a new, dedicated Blast Furnace Gas (BFG) Mittal site. The boiler was retrofitted to operate on the following

on natural gas (only during start-up) on biomass (industrial wood pellets)

at 11% O2, dry) are:

60 mg/Nm³ (BAT)

firing of pulverised wood pellets at row 2 (40 t/h)

firing of pulverised wood pellets at row 2+3 (80 t/h)

up fuel changed from HFO to NG

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The hammer mills are located in a separate concrete building to reduce noise emissions. ation and to allow separate

maintenance. The building is equipped with all necessary accessories to ensure good

To reduce fire and explosion risk and to increase the lifetime of the hammers, additional

in the ash discards was not considered as a major consideration for Max through milling system, without wood dust oversize screening and re-milling,

For Max Green, fast rotating mills by Sprout Matador, were selected. Each mill has a nominal throughput capacity of 10 t/h. The product particle size distribution and the throughput depend the mill screen size. At Rodenhuize, a hammer mill product with a 2.5-3 mm topsize

UBC amount.

A pneumatic conveying system is used to transport the milled wood dust from the 12 from other projects, each

blower feeds a single pneumatic conveying pipe. Despite the higher investments costs, this

ducting, which reduces

The dust/air ratio is an important parameter, which is controlled to ensure proper operation of the burners. Excessive dust/air ratios might cause pulsations and have a negative impact on

up for a new, dedicated Blast Furnace Gas (BFG) Mittal site. The boiler was retrofitted to operate on the following

firing of pulverised wood pellets at row 2+3 (80 t/h)



Date: 15.03.2013

Max Green: Co-firing of pulverised wood pellets at row 1+2+3 (120 t/h)

BFG burners level 5 to l

The major system modifications, in the framework of Max Green, have been:

- NOx abatement system in the flue- Retrofit of the ESP to increase its lifetime and to meet the dust emission limit:- Renewing electrical motors for the ID fans- Modifications to CW pu- New FW pump (incl. Motor - New DCS/Control system

Figure 5: a) after conversion to coal;

Green wood dust firing @ rows 1,2 & 3

BFG burners/NG burners

The BFG burners are out of service most of the time, and openings, of greater than 1.2 m negative impact of the cooling 5, a number of the BFG burners are located at the same level as decided, after several CFD studiesair heater and ESP, as the cooling mediumto combustion air. This tended to limit the disturbance of the biomass flame controlled by undesired air entrance into the boiler.completely modified to ensure the

To create the optimal conditions for the biomass combustionstability without support fuel and match the combustion air supply the biomass burners on levels 1 and 3and hence minimise air in-leakage

The position of the burners for biomass, NG and BFG has been studied extensiveCFD modelling techniques. Ttemperatures of heat exchangers have accelerated ageing of the existing boiler the relocation of the BFG burners



firing of pulverised wood pellets at row 1+2+3 (120 t/h)

BFG burners level 5 to level 2.


abatement system in the flue gas line to meet the BAT emission limits for NOxRetrofit of the ESP to increase its lifetime and to meet the dust emission limit:

electrical motors for the ID fans ump to improve efficiency

mp (incl. Motor and VSD) with higher efficiency New DCS/Control system

a) after conversion to coal; b) Advanced Green, wood dust firing @ rows 2 & 3; c) Max Green wood dust firing @ rows 1,2 & 3.

burners are out of service most of the time, and the cooling of the 1.2 m in diameter),has to be ensured properly, while

negative impact of the cooling air flow on the biomass combustion zone. As shown in BFG burners are located at the same level as the biomass burners.

FD studies, to use low temperature re-circulated flue gascooling medium, because of its lower oxygen content compared

This tended to limit the disturbance of the biomass flame controlled by red air entrance into the boiler. Thereby, the re-circulated flue gas circuit has

completely modified to ensure the effective cooling of the BFG burners.

To create the optimal conditions for the biomass combustion, i.e. ensuring good flame without support fuel and minimising the NO and CO emissions, it is

air supply closely to the fuel flow. The NG burners are combined biomass burners on levels 1 and 3 to reduce the number of new furnace penetration

leakage.

The position of the burners for biomass, NG and BFG has been studied extensiveling techniques. The furnace heat fluxes, the flue gas temperatures and

temperatures of heat exchangers have all been studied in detail to help the existing boiler pressure parts. The results of the

relocation of the BFG burners, among other modifications.

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firing of pulverised wood pellets at row 1+2+3 (120 t/h)


gas line to meet the BAT emission limits for NOx Retrofit of the ESP to increase its lifetime and to meet the dust emission limit:

b) Advanced Green, wood dust firing @ rows 2 & 3; c) Max

the cooling of the large furnace while minimising the As shown in Figure

biomass burners. It was circulated flue gas, taken after

because of its lower oxygen content compared This tended to limit the disturbance of the biomass flame controlled by

circulated flue gas circuit has been

ensuring good flame NO and CO emissions, it is necessary to

he NG burners are combined with to reduce the number of new furnace penetrations,

The position of the burners for biomass, NG and BFG has been studied extensively using heat fluxes, the flue gas temperatures and

detail to help avoid damage and results of the CFD studies led to



Date: 15.03.2013

Burner modifications

The selected technology for biomass fuel firing into the existing boiler furnace. This is OPEX for the combustion of biomass in dry pellet formallows the reuse of the pressure parts the burners and OFA ports.

In terms of OPEX this technology allows high combustion efficiency in comparison to the fluidized bed technology which operates at lower furmeasured boiler efficiency in excess of

The existing coal burners have been modified and quantity of biomass fuel.

New materials have been used on the most criticalerosion rates. The first section of the primary air pipe has been completely covered by ceramic tiles. The shape of the first section of the primary air is hexagonal. This particular shape has several advantages

- The kinetic energy of the wood dust particles is partly absorbed by the edge of the hexagon which is perpendicular to the wood dust flow at the entrance of the burner.

- The hexagon shape allows a good distribution of the wood dust all around the primary air tube.

- Finally because the hexagon is a symmetric shape the primary air tube can be turned by 180° in order to extend the lifetime of the prim ary air tube by presenting another side to the inlet wood dust flow (the side of the hexagon directly impacted iexposed to the highest erosion rate).

The wood dust is transported in dense phase independently from the primary air and is injected in a concentric way inside the primary pipe about one meter upstream the burner. From the injection point of the wood dust inside the primary air pipe every parts of piping subject to erosion havesecondary air pipe in contact with the wood dust has been protected from erosion bhard-facing by welding.

Another challenge was to ensure efficient combustion of support fuel. Prior to the Max Green project,biomass with coal through a number of the burners. Icombustion was well controlledsupported by the pulverised coal flames. It is considered that the far too high and the wood particles were hitting the burning.

During the Max Green project the combustion. The combustion parameters have been experimental tests, to obtain a selfmain parameters influencing the combustion process were the primary air temperature and flow, the secondary air flow and the secondary air swirl.

The boiler start-up is carried out with natural gasdesigned to minimise the requirement for stable flame on 100% biomass. up has been implemented to reduce the start

The installed sootblowing system was not modified for the Max Green project. It is considered, however, that improved



biomass combustion within the Max Green project is pulverized firing into the existing boiler furnace. This is the most effective in terms of CAPEX and

for the combustion of biomass in dry pellet form. In terms of CAPEX this technology e reuse of the pressure parts in the furnace and boiler, except for

In terms of OPEX this technology allows high combustion efficiency in comparison to the fluidized bed technology which operates at lower furnace temperature.

in excess of 90%.

The existing coal burners have been modified significantly in order to cope with the new type

New materials have been used on the most critical parts of the burner to minimise the The first section of the primary air pipe has been completely covered by

The shape of the first section of the primary air is hexagonal. This particular shape has several advantages:

The kinetic energy of the wood dust particles is partly absorbed by the edge of the hexagon which is perpendicular to the wood dust flow at the entrance of the burner. The hexagon shape allows a good distribution of the wood dust all around the primary

Finally because the hexagon is a symmetric shape the primary air tube can be turned by 180° in order to extend the lifetime of the prim ary air tube by presenting another side to the inlet wood dust flow (the side of the hexagon directly impacted iexposed to the highest erosion rate).

The wood dust is transported in dense phase independently from the primary air and is injected in a concentric way inside the primary pipe about one meter upstream

tion point of the wood dust inside the primary air pipe every parts of piping subject to erosion have been covered by ceramic tiles. The inner side of the secondary air pipe in contact with the wood dust has been protected from erosion b

Another challenge was to ensure efficient combustion of the milled biomass without any fuel. Prior to the Max Green project, Unit 4 at Rodenhuize was cowith coal through a number of the burners. In this operating condition

combustion was well controlled, but the biomass combustion was more supported by the pulverised coal flames. It is considered that the wood particle far too high and the wood particles were hitting the opposite membrane walls without

During the Max Green project the burners have been converted for 100% biomass combustion parameters have been modified, based on the results to obtain a self-sustaining stable flame at the outlet of each burner.

main parameters influencing the combustion process were the primary air temperature and flow, the secondary air flow and the secondary air swirl.

up is carried out with natural gas support. The current startdesigned to minimise the requirement for natural gas support, before the establishment of a stable flame on 100% biomass. A complex combustion air regulation sequence up has been implemented to reduce the start-up period using natural gas.

blowing system was not modified for the Max Green project. It is considered, however, that improved sootblowing systems in the convection and radiation part

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combustion within the Max Green project is pulverized the most effective in terms of CAPEX and

In terms of CAPEX this technology for the modification of

In terms of OPEX this technology allows high combustion efficiency in comparison to the nace temperature. This results in a

in order to cope with the new type

of the burner to minimise the The first section of the primary air pipe has been completely covered by

The shape of the first section of the primary air is hexagonal. This particular

The kinetic energy of the wood dust particles is partly absorbed by the edge of the hexagon which is perpendicular to the wood dust flow at the entrance of the burner. The hexagon shape allows a good distribution of the wood dust all around the primary

Finally because the hexagon is a symmetric shape the primary air tube can be turned by 180° in order to extend the lifetime of the prim ary air tube by presenting another side to the inlet wood dust flow (the side of the hexagon directly impacted is obviously

The wood dust is transported in dense phase independently from the primary air and is injected in a concentric way inside the primary pipe about one meter upstream of the inlet to

tion point of the wood dust inside the primary air pipe every parts of he inner side of the

secondary air pipe in contact with the wood dust has been protected from erosion by using

biomass without any co-firing up to 50%

ing condition, the coal more erratic, and was

wood particle velocity was opposite membrane walls without

burners have been converted for 100% biomass modified, based on the results

ame at the outlet of each burner. The main parameters influencing the combustion process were the primary air temperature and

start-up procedure is support, before the establishment of a

sequence during start-

blowing system was not modified for the Max Green project. It is in the convection and radiation part



Date: 15.03.2013

of the boiler may be required after conversion to 100% biomass firing.

Dust abatement

The existing electrostatic precipitator of the Rodenhuize 4 was designed for the treatmentflue gas issued from the coal combustion and for dust concentration amg/Nm³ at 6% O2, dry gas. TO2, dry gas.

In the framework of the Max-G

- To increase the remaining lifetime of the filter,- To improve the dust capture efficiency to meet the

The performance of the ESP filter depends, among otherthe flue gases and the collector electrodes of the filterbe improved by increasing the surfaces of the collecting plates

The experience from Rodenhuize indicatelevel around 7-8 mg/Nm³ requ

The particle contact time is dependent on firing. Although the biomass materials have relatively low ash contents, the ash particles tend to be smaller than coal fly ash and

The optimisation of the ESP filter consisted of moving the insulators to the filter top casing to increase by about 20% the length

- Replacement of the discharge electrodes (DE) of the filter. - Modification of the ESP filte- Modification of the collector plates, to increase wi

mm (now standard) increase length (horiz- The installation of a new rapping system. - In case the space in between the CE plates would be increased from 300

mm, the secondary voltage (HS Trafos) has to be increased accordingly.

An alternative solution for the increase of the dust capture performance is a so called “Hybrid system”, which has a fabric filter install

- the first field remains ESP;- the ESP fields 2-4 are

Normally such a modification can be carried out within an existing casing of an ESP filter. However, this has to be evaluated case by case.

DeNOx

The combustion process releases NOmolecular nitrogen N2 contained into the combustion air, and chemically bound nitrogen N contained into the fuel. A third reaction exists, the hydrocarbon radical, but its incidence on NO

The factors which affect the chamber temperature and the flame temperature, the residence time, the excess airand the fuel particle sizes.

As a primary NOx reduction measure, low NOan OFA system, which provide with acceptable burnout levels



may be required in cases where more severe slagging and biomass firing.

The existing electrostatic precipitator of the Rodenhuize 4 was designed for the treatmentflue gas issued from the coal combustion and for dust concentration a

The future emissions values for this plant are

Green project, the existing ESP filter was retrofitted:

To increase the remaining lifetime of the filter, To improve the dust capture efficiency to meet the new emission level.

The performance of the ESP filter depends, among other things, on the contact time between the flue gases and the collector electrodes of the filter, and the performance of the filter cbe improved by increasing the surfaces of the collecting plates

xperience from Rodenhuize indicates that for 100% wood dust firing a dust emission requires a contact time of 27.5 seconds.

dependent on the flue gas flow rate which is different for biomass Although the biomass materials have relatively low ash contents, the ash particles tend

to be smaller than coal fly ash and are more difficult to capture.

P filter consisted of moving the insulators to the filter top casing to by about 20% the length of the collector plates. This design optimi

Replacement of the discharge electrodes (DE) of the filter. Modification of the ESP filter top casing to put the insulators on top.

e collector plates, to increase width of passage from 300mm (now standard) increase length (horizontal) of the collector plates

ew rapping system. space in between the CE plates would be increased from 300

mm, the secondary voltage (HS Trafos) has to be increased accordingly.

An alternative solution for the increase of the dust capture performance is a so called “Hybrid a fabric filter installed in the last fields:

remains ESP; 4 are replaced with a fabric filter.

Normally such a modification can be carried out within an existing casing of an ESP filter. evaluated case by case.

The combustion process releases NOx, which mainly result from the oxidation of the contained into the combustion air, and chemically bound nitrogen N

A third reaction exists, the reaction of molecular nitrogen Nhydrocarbon radical, but its incidence on NOx formation is minimal.

which affect the NOx emissions are the fuel specification, the combustion chamber temperature and the flame temperature, the residence time, the excess air

reduction measure, low NOx burners have been installedwhich provide low excess air combustion at burner level

levels.

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slagging and fouling is expected

The existing electrostatic precipitator of the Rodenhuize 4 was designed for the treatment of flue gas issued from the coal combustion and for dust concentration at the stack of 80

for this plant are 15 mg/Nm³ at 6%

reen project, the existing ESP filter was retrofitted:

emission level.

s, on the contact time between the performance of the filter can

dust firing a dust emission

which is different for biomass Although the biomass materials have relatively low ash contents, the ash particles tend

P filter consisted of moving the insulators to the filter top casing to This design optimisation involved:

r top casing to put the insulators on top. dth of passage from 300 mm to 400

) of the collector plates;

space in between the CE plates would be increased from 300 mm to 400 mm, the secondary voltage (HS Trafos) has to be increased accordingly.

An alternative solution for the increase of the dust capture performance is a so called “Hybrid

Normally such a modification can be carried out within an existing casing of an ESP filter.

, which mainly result from the oxidation of the contained into the combustion air, and chemically bound nitrogen N

reaction of molecular nitrogen N2 with

emissions are the fuel specification, the combustion chamber temperature and the flame temperature, the residence time, the excess air level,

burners have been installed, combined with low excess air combustion at burner level, for NOx control



Date: 15.03.2013

To achieve the required NOx emission limits of reduction measure were requiredwas proposed. This technology is well known in case of coal combustion, experience with the 100% wood pellets the beginning of the Max Green proje

The main first challenge was to catalyst formulation, catalyst geometry, reactor sizing, design temperature, NHand SO2 conversion, in order to make it suitable for the project.

Based on the test results from wood pellet boiler, it was possible to choose all the design parameters to catalyst lifetime and to get all the typerformance of the SCR system designed for technical significant achievement

The most relevant flue gas paramet

Flue gas composition:

- The combustion of wood pellets results in flue gas with the higher concentrations of some volatile poisonous components for the catalyst, some of the trace elements. of the catalyst, and therefore on the catalyst formulation and SCR design

- The flue gas from biomass combustion contains lhigher levels of alkali NH3 slip design.

- The SO3 concentrations in This has an impact on

Flue gas temperature:

- The experience has been that the lower flue gas temperature after the economisconcentrations in the flue gas, the lower working temperature of the DeNOx catalyst allows adaptation of the catalyst formulationthe risk of SO3 related problems in the DeNOincrease the catalyst activity, the concentration(vanadium, tungsten, molybdenum)

- There has been a significant CAPEX decrease resultrequirement to split the economiser surface load.

Flue gas flow:

- The SCR reactor is designed to ensure an allowable i.e. higher flue gas flow rate

- This design also ensures an advantageous area velocity for the biomass mode, not taking into account the cool the BFG burners.

Taking into account these project specific factors layer SCR reactor was installed in order to ensure acceptable catalyst life time.

At the Rodenhuize power station a 24in the flue gases, without first



NOx emission limits of 90 mg/Nm³ at 6% Owere required. The installation of a Selective Catalytic Reduction system

his technology is well known in case of coal combustion, the 100% wood pellets pulverised fuel boiler with high-dust SCR system at

the beginning of the Max Green project.

The main first challenge was to define the catalyst and SCR design parameterscatalyst formulation, catalyst geometry, reactor sizing, design temperature, NH

conversion, in order to make it suitable for the requirements of the

test results from a high-dust SCR pilot installation of Laborelec on a 100% boiler, it was possible to choose all the design parameters to

catalyst lifetime and to get all the typical guarantees for such a SCR retrofit.performance of the SCR system designed for the Max Green project represent

achievement for Electrabel, Laborelec and Tractebel Engineering.

he most relevant flue gas parameters are:

he combustion of wood pellets results in flue gas with the higher concentrations of some volatile poisonous components for the catalyst, principally the some of the trace elements. These elements can have a direct impact on the life time

and therefore on the catalyst formulation and SCR designThe flue gas from biomass combustion contains lower fly ash

metals, leading to a different catalyst geometry and different

centrations in the flue gas with 100% wood combustion the SO2 conversion level and the SCR design.

experience has been that the conversion from coal to 100% s temperature after the economiser. In combination

in the flue gas, the lower working temperature of the DeNOx catalyst the catalyst formulation in order to increase its activity, without

related problems in the DeNOx reactor and in the air preincrease the catalyst activity, the concentrations of the active catalyst elements (vanadium, tungsten, molybdenum) are typically increased.

significant CAPEX decrease resulting from the absence of the economiser surface to maintain the SCR temperature at part

The SCR reactor is designed to ensure an allowable performance when firing BFG, higher flue gas flow rates and no SCR by-pass.

This design also ensures an advantageous area velocity for the biomass mode, not taking into account the requirement for flue gas recirculation on the burner levels

.

project specific factors for the Max Green project, a 3+1 catalyst installed in order to ensure the required NO

power station a 24.5% NH4OH solution is evaporated and directly injected first mixing with hot air. This solution reduces the consumption of

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% O2 secondary NOx f a Selective Catalytic Reduction system

his technology is well known in case of coal combustion, but there was no dust SCR system at

parameters, i.e. the catalyst formulation, catalyst geometry, reactor sizing, design temperature, NH3 slip design

requirements of the Max Green

Laborelec on a 100% boiler, it was possible to choose all the design parameters to maximise the

pical guarantees for such a SCR retrofit. The the Max Green project represents therefore a

for Electrabel, Laborelec and Tractebel Engineering.

he combustion of wood pellets results in flue gas with the higher concentrations of principally the alkali metals and

elements can have a direct impact on the life time and therefore on the catalyst formulation and SCR design.

fly ash concentrations but rent catalyst geometry and different

the flue gas with 100% wood combustion are very low. SCR design.

100% wood resulted in In combination with the low SO2

in the flue gas, the lower working temperature of the DeNOx catalyst in order to increase its activity, without

reactor and in the air pre-heater. To of the active catalyst elements

from the absence of the to maintain the SCR temperature at part

ce when firing BFG,

This design also ensures an advantageous area velocity for the biomass mode, not flue gas recirculation on the burner levels to

Max Green project, a 3+1 catalyst NOx reduction and

OH solution is evaporated and directly injected This solution reduces the consumption of



Date: 15.03.2013

auxiliary steam or electricity and limits the loss of efficiency due to steam extractionturbine.

A second challenge was linked to the integration of the SCR reactor in the already congested flue gas duct area.the furnace chamber and the ESP.supporting the 400-tonne reactor had to be installed and supported by substantial foundations, in order to reach the boiler outlet duct l

DeSOx

Because of the low sulphur contenthe flue gases remain below the equipment in the flue gas system


Boiler performance at 50% biomass the

During the Advanced Green phase, wood pelletlower row 1 was used for coal. The existing coal burners and part of the pulverized coal transport system were reused for wood. The wood combustion was probAdvanced Green configuration. Owing to the large size of the biggest particles, the worse particle size distribution and the irregular shape of wood particles compared to PC particles, the fuel feeding resulted rather difficult, especially wpulsing and sedimentation in the fuel lines and to overcome the pressure losses, the feeding velocity had to be kept very high (30 m/s or even faster). This resulted in a too high velocity at the burner outlet, causing the flame to be very unstable and not attached to the burner. The pulverized wood was even “projected” in the boiler, which caused flame impingement to the opposite and side walls, a bad combustion with a large amount of fly ash, post-combustion in the convective part and increased slagging and fouling in the combustion chamber as well as at the convective part inlet. The burnout was not complete at 43 meters and it is known that secondary combustion of coarse particles on heat transsurfaces can create local reducing zones that favour slagging.

Boiler performance at 100% biomass input

After changing the burners and modifying the boiler for the Max Green configuration as described in chapter 3, the combustion resulted much more staUBC in the ashes, no flame impingement.

Slagging and fouling

As main conclusion of the deposit analyses on the probes, it came out that there was a spread of molten salts which causes a sulphate layer on the metal surface, loss of the oxide layer as a consequence. The particles were large and sintered, and problematic to clean. The recommendations were to maintain a stable and constant firing system, to avoid fluctuating temperatures, and to be sure that the the tubes was good before co

Another finding was the confirmation of the postpart. The burn-out was not complete at 43 meters and it is known that secondary combustof coarse particles on heat transfer surfaces can create local reducing zones that favour slagging.

The ash fusion temperature, more specifically the initial deformation temperature of the wood ashes at that time, was about 1150 °C, which is low compar

After the first months of Max Green operation, slagging has increased considerably, resulting in stops for manual cleaning. The origin of the slagging is probably a decreased pellet



auxiliary steam or electricity and limits the loss of efficiency due to steam extraction

A second challenge was linked to the integration of the SCR reactor in the already flue gas duct area. The SCR reactor is located above the air pre

the furnace chamber and the ESP. A substantial steel structure of about 1,reactor had to be installed and supported by substantial

in order to reach the boiler outlet duct located at an elevation of 70 m.

Because of the low sulphur content in the industrial wood pellets, the SOthe emission limit without the requirement for a

system.


Boiler performance at 50% biomass the rmal input

During the Advanced Green phase, wood pellets were fired on the boiler rows 2 and 3. The lower row 1 was used for coal. The existing coal burners and part of the pulverized coal transport system were reused for wood. The wood combustion was probAdvanced Green configuration. Owing to the large size of the biggest particles, the worse particle size distribution and the irregular shape of wood particles compared to PC particles, the fuel feeding resulted rather difficult, especially where the pipes bend. In order to avoid pulsing and sedimentation in the fuel lines and to overcome the pressure losses, the feeding velocity had to be kept very high (30 m/s or even faster). This resulted in a too high velocity

g the flame to be very unstable and not attached to the burner. The pulverized wood was even “projected” in the boiler, which caused flame impingement to the opposite and side walls, a bad combustion with a large amount of UBC

combustion in the convective part and increased slagging and fouling in the combustion chamber as well as at the convective part inlet. The burnout was not complete at 43 meters and it is known that secondary combustion of coarse particles on heat transsurfaces can create local reducing zones that favour slagging.

Boiler performance at 100% biomass input

After changing the burners and modifying the boiler for the Max Green configuration as described in chapter 3, the combustion resulted much more stable, with much less slagging,

in the ashes, no flame impingement.

As main conclusion of the deposit analyses on the probes, it came out that there was a spread of molten salts which causes a sulphate layer on the metal surface, loss of the oxide layer as a consequence. The particles were large and sintered, and problematic to clean. The recommendations were to maintain a stable and constant firing system, to avoid fluctuating temperatures, and to be sure that the protective oxide layer on the tubes was good before co-combustion of biomass.

Another finding was the confirmation of the post-combustion of particles in the convective out was not complete at 43 meters and it is known that secondary combust

of coarse particles on heat transfer surfaces can create local reducing zones that favour

The ash fusion temperature, more specifically the initial deformation temperature of the wood ashes at that time, was about 1150 °C, which is low compared to coal.


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auxiliary steam or electricity and limits the loss of efficiency due to steam extraction on the

A second challenge was linked to the integration of the SCR reactor in the already very reactor is located above the air pre-heaters, between

ture of about 1,000 tonnes reactor had to be installed and supported by substantial

ocated at an elevation of 70 m.

the SOx concentrations in without the requirement for additional deSOx

fired on the boiler rows 2 and 3. The lower row 1 was used for coal. The existing coal burners and part of the pulverized coal transport system were reused for wood. The wood combustion was problematic in the Advanced Green configuration. Owing to the large size of the biggest particles, the worse particle size distribution and the irregular shape of wood particles compared to PC particles,

here the pipes bend. In order to avoid pulsing and sedimentation in the fuel lines and to overcome the pressure losses, the feeding velocity had to be kept very high (30 m/s or even faster). This resulted in a too high velocity

g the flame to be very unstable and not attached to the burner. The pulverized wood was even “projected” in the boiler, which caused flame impingement to

UBC in the bottom and combustion in the convective part and increased slagging and fouling in the

combustion chamber as well as at the convective part inlet. The burnout was not complete at 43 meters and it is known that secondary combustion of coarse particles on heat transfer

After changing the burners and modifying the boiler for the Max Green configuration as ble, with much less slagging,

As main conclusion of the deposit analyses on the probes, it came out that there was a spread of molten salts which causes a sulphate layer on the metal surface, with cracks and loss of the oxide layer as a consequence. The particles were large and sintered, and problematic to clean. The recommendations were to maintain a stable and constant firing

protective oxide layer on

combustion of particles in the convective out was not complete at 43 meters and it is known that secondary combustion

of coarse particles on heat transfer surfaces can create local reducing zones that favour

The ash fusion temperature, more specifically the initial deformation temperature of the wood




Date: 15.03.2013

quality, but also combustion problems can be athe problem, following action scheme is set up:

- Follow up the pellet quality more frequently and accurately;- Install a 2D temperature mapping, as knowing the temperature profile is necessary to

keep the combustion process un- Optimise the sootblowing system (the most recent developments such as “intelligent

sootblowing” systems are examples of strongly optimised sootblowing with much better results and less medium consumption than

- Follow up the post-combustion in the convective part, as this can also lead to increased slagging;

- Optimise the air repartition (swirl, secondary/tertiary air, etc.).


Evaluation of SCR performance

Biomass combustion reduced the NOx emissions.average. The slightly more than half reduction may indicate the need to improve the performance of the catalyst by operational controls and the ammonia distribution or flow.

Measures of NH3 slip after catalyst have shown very low concentrations. The stoichiometry between NH3 and NOx were estimated below or near 1 in all the investigated periods. This shows that the ammonia flow for the NOx reduction was not high enough to reach optimalconditions in the catalyst. This also would explain the low NOx conversion.

Evaluation of ESP performance

The dust composition during Max Green tests after retrofitting showed that the CaO, SiOand K2O contents are the major compounds. This implicates thsulphur of the biomass ends up in the fly ash. A high amount of shows that the incineration of the biomass particles was not satisfying.

There was a big influence of dust removal efficiency before and afteHigher dust emissions before ESP have been measured during 50% cocompared to 100% wood firing, due to higher ash content in the fuel. Nevertheless the dust emissions after ESP to stack were similar for both firing scretrofit, PM1 fraction after the ESP (emitted to stack) represents dust load.

The composition of the fine fractions during 100similar. While the coarse fraction contains mainly alumina silicates which have been separated in the ESP, the fine fraction is composed mainly by salts KCl, NaCl, KCaSO4.

Evaluation of gas emissions

NOx emissions are in a small range and the SOattributed to a low amount of sulphur in the biomass and the neutralization effect of the fly ash with high alkali- and calcium oxide content. Only some peaks are detected. The peaks for the CO emission are much stronger and can be attributed to the The dust emission was very low due to the fact that the ESP was retrofitted with enhancements to the flow pattern and electrical part and is oversized because of the higher ash content of the coal for which it was designed.



quality, but also combustion problems can be at the origin. In order to analysthe problem, following action scheme is set up:

Follow up the pellet quality more frequently and accurately; Install a 2D temperature mapping, as knowing the temperature profile is necessary to keep the combustion process under control and to reveal potential problems;Optimise the sootblowing system (the most recent developments such as “intelligent sootblowing” systems are examples of strongly optimised sootblowing with much better results and less medium consumption than former systems);

combustion in the convective part, as this can also lead to

Optimise the air repartition (swirl, secondary/tertiary air, etc.).

Air pollution control devices

Evaluation of SCR performance

combustion reduced the NOx emissions. The NOx reduction was about 55average. The slightly more than half reduction may indicate the need to improve the performance of the catalyst by operational controls and the ammonia distribution or flow.

slip after catalyst have shown very low concentrations. The stoichiometry and NOx were estimated below or near 1 in all the investigated periods. This

shows that the ammonia flow for the NOx reduction was not high enough to reach optimalconditions in the catalyst. This also would explain the low NOx conversion.

Evaluation of ESP performance

The dust composition during Max Green tests after retrofitting showed that the CaO, SiOO contents are the major compounds. This implicates that most of the alkali and

sulphur of the biomass ends up in the fly ash. A high amount of UBC in the fly asshows that the incineration of the biomass particles was not satisfying.

There was a big influence of dust removal efficiency before and after retrofitting of ESP. Higher dust emissions before ESP have been measured during 50% co

% wood firing, due to higher ash content in the fuel. Nevertheless the dust emissions after ESP to stack were similar for both firing scenarios. Before and after the boiler retrofit, PM1 fraction after the ESP (emitted to stack) represents 70% by weight of the total

f the fine fractions during 100% wood and 50/50 wood/coal scenario is raction contains mainly alumina silicates which have been

separated in the ESP, the fine fraction is composed mainly by salts KCl, NaCl, K


NOx emissions are in a small range and the SO2 emissions are mostly low and cattributed to a low amount of sulphur in the biomass and the neutralization effect of the fly

and calcium oxide content. Only some peaks are detected. The peaks for the CO emission are much stronger and can be attributed to the soot blowing activities. The dust emission was very low due to the fact that the ESP was retrofitted with enhancements to the flow pattern and electrical part and is oversized because of the higher ash content of the coal for which it was designed.

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order to analyse and remediate

Install a 2D temperature mapping, as knowing the temperature profile is necessary to der control and to reveal potential problems;

Optimise the sootblowing system (the most recent developments such as “intelligent sootblowing” systems are examples of strongly optimised sootblowing with much

former systems); combustion in the convective part, as this can also lead to

The NOx reduction was about 55% in average. The slightly more than half reduction may indicate the need to improve the performance of the catalyst by operational controls and the ammonia distribution or flow.

slip after catalyst have shown very low concentrations. The stoichiometry and NOx were estimated below or near 1 in all the investigated periods. This

shows that the ammonia flow for the NOx reduction was not high enough to reach optimal conditions in the catalyst. This also would explain the low NOx conversion.

The dust composition during Max Green tests after retrofitting showed that the CaO, SiO2 at most of the alkali and

in the fly ash (14%)

r retrofitting of ESP. Higher dust emissions before ESP have been measured during 50% co-firing scenario

% wood firing, due to higher ash content in the fuel. Nevertheless the dust enarios. Before and after the boiler

% by weight of the total

% wood and 50/50 wood/coal scenario is raction contains mainly alumina silicates which have been

separated in the ESP, the fine fraction is composed mainly by salts KCl, NaCl, K2SO4,

emissions are mostly low and can be attributed to a low amount of sulphur in the biomass and the neutralization effect of the fly

and calcium oxide content. Only some peaks are detected. The peaks soot blowing activities.

The dust emission was very low due to the fact that the ESP was retrofitted with enhancements to the flow pattern and electrical part and is oversized because of the higher



Date: 15.03.2013


At Rodenhuize PP the amount of wo(Advanced Green) and later 100% wood pelletthe type fired at Rodenhuize have a fairly widedepending on the level of bark present(0.6-2.3%) than most coals and, as a consequence, the cohas only a modest impact on the chemistry of the mixed ashcontrol of the UBC levels in the ashes can be controlled by the maintenance of acceptable combustion conditions. The industry has already agreed on a qualitypellets which help to maintain adequate control ovstandards will normally permit the ash quality standards for the products of the cothese fuels to be met under normal combustion conditions.

At present, the standard for fly ash for concrete EN 450firing to 20% by mass. However, due to the experience with cothe level of co-firing will be increased to 40% by masswood. The results of the ash tests with this revision of the standard.

100% wood pellet combustion

With 100% wood pellet combustionoriginating from coal combustion and from comagnesium oxide, alkali metals, iron oxide are lower, as would be expected for wood ash. For uticonstituent of cement, it will be the task of the cement producer to decide about the ratio of this ash in his raw meal mix.

The ash may be used as a lime or an alkali agent. considered. These applications may be need to be considered for a specific country or region and regional requirements.



ation of residues

the amount of wood pellet co-firing was increased from 25 to een) and later 100% wood pellet was fuelled (Max Green). W

the type fired at Rodenhuize have a fairly wide range of chemical compositions, normally depending on the level of bark present. The wood pellets have much lower ash contents

2.3%) than most coals and, as a consequence, the co-firing of wood pellets normally has only a modest impact on the chemistry of the mixed ash produced. In most systems, the

levels in the ashes can be controlled by the maintenance of acceptable he industry has already agreed on a quality

help to maintain adequate control over the ash levels in the wood fuels. These standards will normally permit the ash quality standards for the products of the cothese fuels to be met under normal combustion conditions.

At present, the standard for fly ash for concrete EN 450-1 (13) restricts the amount of cofiring to 20% by mass. However, due to the experience with co-firing over the

will be increased to 40% by mass, and 50% by mass in case of green of the ash tests for wood pellets co-firing within DEBCO are consistent

with this revision of the standard.

% wood pellet combustion

With 100% wood pellet combustion, the ash residues differ significanoriginating from coal combustion and from co-firing. The ashes are rich in

metals, phosphate and sulphur. The levels of silica, alumina and , as would be expected for wood ash. For utilisation of this material as a


The ash may be used as a lime or an alkali agent. and its use as a low grade applications may be restricted by trace elements contents, and these

need to be considered for a specific country or region and for the respective national and/or

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was increased from 25 to 50% Wood pellet fuels of

compositions, normally The wood pellets have much lower ash contents

firing of wood pellets normally In most systems, the

levels in the ashes can be controlled by the maintenance of acceptable scheme for wood

er the ash levels in the wood fuels. These standards will normally permit the ash quality standards for the products of the co-firing of

restricts the amount of co-firing over the past few years,

and 50% by mass in case of green within DEBCO are consistent

differ significantly from those are rich in calcium- and

levels of silica, alumina and lisation of this material as a


and its use as a low grade fertiliser can be contents, and these

the respective national and/or



Date: 15.03.2013

6.2 Kardia and Meliti

All the information related to agricultural (olive based on experimental tests performed on Kardia PP and Meliti PP.

The results related to biomass/lignite coperformed on the Unit 1 of Kardia PP with cardoon as biomass atweight).

The chemical analysis of lignite, cardoon and the mixture shows a difference especially in nitrogen, sulphur and chlorine content. However, other variation in the lignite itself, which cardoon at 10% thermal share actually does.

Kardia power plant is located in the Region of West Macedonia, near the cities of and Kozani and utilises indigenous lowmine. Kardia consists of four capacity of 300 MWel, Units 3 MWel. Each unit consists of areheat. After passing through the convective section of the boiler, the flue gas is led to the air pre-heater before passing through the ESPs and the stack. the boiler.

The plant is fuelled with lignite from the nearby Kardia mine, which is transferred via a conveyor belt system and unloaded to a storage space or distributed to the belts of the coal handling.

No DeNOx unit is installed at the Kardia in the fuel ash, flue gas desulphurization is not required

The Meliti PP is located in the Region of Western Macedonia, near the city of Florina and close to the border with FYROM (Former Yugoslav Republic Of Macedonia).

The Meliti PP consists of one unit with an installed capacity of 330 MW2004, it is the newest and one of the most efficient lignitecontrast with the other lignite-for combustion of xylite / lignite, with the percentage of the former being up to 32%. Xylite is a brown coal of similar rank with lignite. However, the lignite is a lithotype with a matrixderived from marsh reeds, sedges, etc., which are rich in cellulose, while the xylite is a lithotype rich in woody material with over

This required special considerations in the design of the boiler and the milling addition, in order to conform to the increasing stricter environmental regulations in the EU, the Meliti PP was designed as abar / 543 °C, and with integrated measures of emission contras a primary measure for NOx reduction and a Flue Gasminimise SOx.

Co-firing tests have been performed in order to identify technical problems that should be avoided during the permanent operaPower Corporation (PPC) organised and carried out the colignite-fired units, while CERTH contributed to the evaluation of results, as regards to operational malfunctions. The tested biomass fuels have been separately olive kernels and cardoons. The biomass was loadedcrushers. The plant was tested at 255



Kardia and Meliti Power Plants (agricultural biomass/lignite co

All the information related to agricultural (olive kernel, cardoon) biomass/lignite coexperimental tests performed on Kardia PP and Meliti PP.

The results related to biomass/lignite co-firing are based on experimental campaigns it 1 of Kardia PP with cardoon as biomass at 10% thermal share (3% by

lignite, cardoon and the mixture shows a difference especially in nitrogen, sulphur and chlorine content. However, other chemical analysisvariation in the lignite itself, which can affect the values of the mixture in larger amount than

on at 10% thermal share actually does.

power plant is located in the Region of West Macedonia, near the cities of es indigenous low-rank coal (lignite) from the nearby Kardia open

consists of four units: Units 1 and 2 (built in 1974 and 1975) and 4 (built in 1980 and 1981) with an installed capacity of 325

Each unit consists of a supercritical Benson type once-through boiler with single er passing through the convective section of the boiler, the flue gas is led to the air

heater before passing through the ESPs and the stack. Figure 6 presents an overview of

lignite from the nearby Kardia mine, which is transferred via a conveyor belt system and unloaded to a storage space or distributed to the belts of the coal

is installed at the Kardia PP. Furthermore, due to the high content of calcium flue gas desulphurization is not required.

The Meliti PP is located in the Region of Western Macedonia, near the city of Florina and YROM (Former Yugoslav Republic Of Macedonia).

The Meliti PP consists of one unit with an installed capacity of 330 MWe

2004, it is the newest and one of the most efficient lignite-fired power plants of PPC. In -fired power plants operating in Greece, Meliti PP was designed

for combustion of xylite / lignite, with the percentage of the former being up to 32%. Xylite is a brown coal of similar rank with lignite. However, the lignite is a lithotype with a matrixderived from marsh reeds, sedges, etc., which are rich in cellulose, while the xylite is a lithotype rich in woody material with over 10% stems and rich in lignin.

This required special considerations in the design of the boiler and the milling addition, in order to conform to the increasing stricter environmental regulations in the EU, the Meliti PP was designed as a supercritical boiler, with maximum steam parameters of 235

°C, and with integrated measures of emission contr ol, such as Oas a primary measure for NOx reduction and a Flue Gas Desulphurization (FGD) unit to

performed in order to identify technical problems that should be permanent operation with secondary fuels, planned until 2022

organised and carried out the co-firing trials in the older 300fired units, while CERTH contributed to the evaluation of results, as regards to

The tested biomass fuels have been separately olive kernels and The biomass was loaded to the feeding system and mixed with lignite before the

The plant was tested at 255-290 MWel with 10% biomass thermal share

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biomass/lignite co -firing)

, cardoon) biomass/lignite co-firing is

rimental campaigns 10% thermal share (3% by

lignite, cardoon and the mixture shows a difference especially in chemical analysis show a broad

can affect the values of the mixture in larger amount than

power plant is located in the Region of West Macedonia, near the cities of Ptolemaida rank coal (lignite) from the nearby Kardia open-cast

2 (built in 1974 and 1975) with an installed with an installed capacity of 325

through boiler with single er passing through the convective section of the boiler, the flue gas is led to the air

presents an overview of

lignite from the nearby Kardia mine, which is transferred via a conveyor belt system and unloaded to a storage space or distributed to the belts of the coal

ue to the high content of calcium

The Meliti PP is located in the Region of Western Macedonia, near the city of Florina and YROM (Former Yugoslav Republic Of Macedonia).

el. Commissioned in fired power plants of PPC. In

fired power plants operating in Greece, Meliti PP was designed for combustion of xylite / lignite, with the percentage of the former being up to 32%. Xylite is a brown coal of similar rank with lignite. However, the lignite is a lithotype with a matrix coal derived from marsh reeds, sedges, etc., which are rich in cellulose, while the xylite is a

This required special considerations in the design of the boiler and the milling system. In addition, in order to conform to the increasing stricter environmental regulations in the EU,

supercritical boiler, with maximum steam parameters of 235 Over-Fire Air (OFA)

Desulphurization (FGD) unit to

performed in order to identify technical problems that should be , planned until 2022. Public

firing trials in the older 300-MWel fired units, while CERTH contributed to the evaluation of results, as regards to

The tested biomass fuels have been separately olive kernels and to the feeding system and mixed with lignite before the

with 10% biomass thermal share.



Date: 15.03.2013

Figure 6 :

6.2.1 Handling, storage and

The existing secondary fuel handling system fuels with characteristics similar to olive kernelto fossil fuels and not herbaceous biomass).baled biomass, since constant feeding is not assured. Accumulation of biomass appbe the main issue, while suirecirculation system can be bypassed even by quite large biomass particles. This might be a risk factor.

The existing, not for biomass optimiskernels.

Feeding system. No material accumulation was attested in any part of the feeding system during co-firing with olive kernelpractically blocked in several places long the feeding line when balThe feeding of a homogenized mixture of chopped cardoonpellets and lignite at Meliti PP did not cause any feeding issues; however, it required significant planning on the part of the coal yard operatorfuel mixing.

Mills. No mill energy increase correlated with cogrindability during the co-firing test was 0.5% lower at the 1the 200 µm sieve compared tbaled cardoon, significant biomass accumulation was found in the mills, used for cardoon. In fact, fibrous material like cardoon is difficult to be crushed with beater mills; the portion of coarse grain is high and, consequently, the combustion performance is reduced. Anyhow, the mill performance regarding the lignite appears unaffected by the presence of small quantities of herbaceous biomass. As for theincrease was detected. The temperature values were within the usual range of mill operation (90 – 135 °C) and well within the



: Overview of the boiler installed at Kardia PP.

Handling, storage and milling

fuel handling system of Kardia PP is capable of handling biomass fuels with characteristics similar to olive kernels (small particle size, grindability comparable to fossil fuels and not herbaceous biomass). On the contrary, it is unsuitable for handling baled biomass, since constant feeding is not assured. Accumulation of biomass app

suitable particle size reduction is not guaranteed. The mill recirculation system can be bypassed even by quite large biomass particles. This might be a

xisting, not for biomass optimised, fuel handling system has little difficulties with ol

No material accumulation was attested in any part of the feeding system firing with olive kernels, whereas significant cardoon quantities were found

practically blocked in several places long the feeding line when baled biomass was used. The feeding of a homogenized mixture of chopped cardoons and lignite at Kardia PP and of pellets and lignite at Meliti PP did not cause any feeding issues; however, it required significant planning on the part of the coal yard operator and increased expenditures for the

No mill energy increase correlated with co-firing was detected. firing test was 0.5% lower at the 1-mm sieve and 1.75% lower at

m sieve compared to the tests without co-firing. Furthermore, after the test with baled cardoon, significant biomass accumulation was found in the mills, even in the ones not

. In fact, fibrous material like cardoon is difficult to be crushed with beater mills; the portion of coarse grain is high and, consequently, the combustion performance is reduced. Anyhow, the mill performance regarding the lignite appears unaffected by the presence of small quantities of herbaceous biomass. As for the temperature in

detected. The temperature values were within the usual range of mill operation the safe operation limits.

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is capable of handling biomass (small particle size, grindability comparable

is unsuitable for handling baled biomass, since constant feeding is not assured. Accumulation of biomass appears to

table particle size reduction is not guaranteed. The mill recirculation system can be bypassed even by quite large biomass particles. This might be a

has little difficulties with olive

No material accumulation was attested in any part of the feeding system , whereas significant cardoon quantities were found

ed biomass was used. and lignite at Kardia PP and of

pellets and lignite at Meliti PP did not cause any feeding issues; however, it required and increased expenditures for the

However, the fuel mm sieve and 1.75% lower at

firing. Furthermore, after the test with even in the ones not

. In fact, fibrous material like cardoon is difficult to be crushed with beater mills; the portion of coarse grain is high and, consequently, the combustion performance is reduced. Anyhow, the mill performance regarding the lignite appears unaffected by the

mperature in the mills, no detected. The temperature values were within the usual range of mill operation



Date: 15.03.2013

No impact on mill operation was detected for the coKardia PP. Summarising, the handling of baled cardoon has been proved to be difficult and to require dedicated solutions. Delivering cardoon as chopped material made possible the production of a homogenized fuel mixture in the yard that was used during meaowing to the low weight of the material, even the presence of wind can be an issue. Nevertheless, an investment in a permanent milling and feeding system for biomass might be useful even for olive kernels.


CFD simulations were realised with commercial software. The scope of the activities was to identify the optimum size of the biomass particles for the comost important properties of the biomass particles is the nonmodels for biomass combustion and equation of motion were implemented in the CFD model. The investigations were mostly focused on the effect of the biomass particle size onthe fuel burnout. Different options of biomass feeding were inoptimum positions for biomass injection. Based on the reference case (lignite feeding at nominal load), differences were estimated in the combustion performance when adding biomass. The results include calculations on velocity anparameters, such as NOx emissions, were also considered and heat and mass balance calculations result for the various co

Figure 7: Boiler geometry of Kardia PP and schematic represent



No impact on mill operation was detected for the co-milling of a lignite / pellet mixture at

ing, the handling of baled cardoon has been proved to be difficult and to require dedicated solutions. Delivering cardoon as chopped material made possible the production of a homogenized fuel mixture in the yard that was used during measurements. Moreover, owing to the low weight of the material, even the presence of wind can be an issue.

n investment in a permanent milling and feeding system for biomass might be

Boiler modification

simulations were realised with commercial software. The scope of the activities was to identify the optimum size of the biomass particles for the co-firing ratio to be used. On

of the biomass particles is the non-roundness. models for biomass combustion and equation of motion were implemented in the CFD model. The investigations were mostly focused on the effect of the biomass particle size on

fuel burnout. Different options of biomass feeding were investigated to identify the optimum positions for biomass injection. Based on the reference case (lignite feeding at nominal load), differences were estimated in the combustion performance when adding biomass. The results include calculations on velocity and temperature fields. Other parameters, such as NOx emissions, were also considered and heat and mass balance calculations result for the various co-firing scenarios.

Boiler geometry of Kardia PP and schematic representation of simulated burner geometry

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milling of a lignite / pellet mixture at

ing, the handling of baled cardoon has been proved to be difficult and to require dedicated solutions. Delivering cardoon as chopped material made possible the production of

surements. Moreover, owing to the low weight of the material, even the presence of wind can be an issue.

n investment in a permanent milling and feeding system for biomass might be

simulations were realised with commercial software. The scope of the activities was to firing ratio to be used. One of the

. Therefore, updated models for biomass combustion and equation of motion were implemented in the CFD model. The investigations were mostly focused on the effect of the biomass particle size on

vestigated to identify the optimum positions for biomass injection. Based on the reference case (lignite feeding at nominal load), differences were estimated in the combustion performance when adding

d temperature fields. Other parameters, such as NOx emissions, were also considered and heat and mass balance

ation of simulated burner geometry.



Date: 15.03.2013

Operating Scenarios

CFD simulations were performed based on current fullcombustion and heat and mass balance calculations results for the various coscenarios.

The biomass particle size is a key parameter in the evaluation of CFD results. Therenumber of cases were considered.

Two biomass diameters are examined (1 mm and 5 mm). The smaller particle size corresponds to typical biomass size for coseparate size-reduction step. The larger particle size, which is somewhat higher than the typical size ranges for co-firing, is achieved directly at the field when the collection of cardoon is performed with forage harvesters.

Results of the CFD modeling

- Overall, several important operational parameters are unaffected by coat low thermal loading: the furnace exit temperature is only slightly increased, so there is no expectancy of intensifying slagging/fouling phenomena related to the lignite particles in comparison with the reference transfer to the furnace wall is likewise unaffected. CFD analysis suggests that a potential benefit of comostly due to the lower nitrogen content of the biomass fuel and the respective mechanism for fuel NOx formation. This trend is well attested by literature and pilot scale testing, but not by short term testing in the examined large scale boiler.

- The main impact of colosses from the hopper are increased for lignite particles under coburnout of the particles exiting through the main outlet is largely unaffected. For biomass particles, the size is of outmost importance; particles with an equivalent diameter of 5 mm do not fall through the hopper unless they enter through the lower main burner, but exhibit very low char burnouts despite increased residence times. Smaller particles, with burnouts for all burner levels, despite being at least one size category larger than lignite particles. The increased hopper losses during coparticle have been verified by expe

- Particles entering the furnace through the lower main burner differ significantly in their trajectories compared to all other burner levels. The recirculation zone of the flow field in the upper hopper reseveral particles, which fall initially into the hopper region and then find their way in the upward current as they gradually loss weight. On the other hand, depending on flow field intensity and particle density, a number of particles leave the furnace from the hopper with relatively high

- Biomass particles that have undergone significant size reduction before entering the furnace pose no significant problems in which are not subjected to separate size reduction or for which current size reduction techniques are ineffective, increase the Although the overall boiler combustion efficiency is not grealow fixed carbon content of the biomass particles, other issues may occur, such as sintering of unburned fly and bottom ash disposal routes due to higher problems will increase with higher co

- In conclusion, for the investigated boiler there appear to be two potential coschemes, which should be further evaluated according to techno



CFD simulations were performed based on current full-load operating conditions for lignite combustion and heat and mass balance calculations results for the various co

particle size is a key parameter in the evaluation of CFD results. Therenumber of cases were considered.

Two biomass diameters are examined (1 mm and 5 mm). The smaller particle size corresponds to typical biomass size for co-firing applications and can be achieved through a

reduction step. The larger particle size, which is somewhat higher than the firing, is achieved directly at the field when the collection of cardoon arvesters.

sults of the CFD modeling

Overall, several important operational parameters are unaffected by coat low thermal loading: the furnace exit temperature is only slightly increased, so there is no expectancy of intensifying slagging/fouling phenomena related to the

te particles in comparison with the reference operational scenario. The total heat transfer to the furnace wall is likewise unaffected. CFD analysis suggests that a potential benefit of co-firing conditions is a decrease of NOx emissions up to 10%,

to the lower nitrogen content of the biomass fuel and the respective mechanism for fuel NOx formation. This trend is well attested by literature and pilot

but not by short term testing in the examined large scale boiler.of co-firing concerns the char burnout for lignite and biomass.

losses from the hopper are increased for lignite particles under coparticles exiting through the main outlet is largely unaffected. For

the size is of outmost importance; particles with an equivalent diameter of 5 mm do not fall through the hopper unless they enter through the lower main burner, but exhibit very low char burnouts despite increased residence times. Smaller particles, with an equivalent diameter of 1 mm, exhibit very high char burnouts for all burner levels, despite being at least one size category larger than lignite particles. The increased hopper losses during co-firing of large biomass particle have been verified by experimental results of a co-firing campaign at KardiaParticles entering the furnace through the lower main burner differ significantly in their trajectories compared to all other burner levels. The recirculation zone of the flow field in the upper hopper region tends to increase the trajectories and residence time of several particles, which fall initially into the hopper region and then find their way in the upward current as they gradually loss weight. On the other hand, depending on

nd particle density, a number of particles leave the furnace from the hopper with relatively high UBC content. Biomass particles that have undergone significant size reduction before entering the furnace pose no significant problems in the boiler operation. Larger biomass particles, which are not subjected to separate size reduction or for which current size reduction techniques are ineffective, increase the UBC content in the hopper and fly ash. Although the overall boiler combustion efficiency is not greatly decreased due to the low fixed carbon content of the biomass particles, other issues may occur, such as

fly ash particles at heat exchange surfaces or problems in the fly and bottom ash disposal routes due to higher UBC content. The intensity of these problems will increase with higher co-firing ratios. In conclusion, for the investigated boiler there appear to be two potential coschemes, which should be further evaluated according to techno

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load operating conditions for lignite combustion and heat and mass balance calculations results for the various co-firing

particle size is a key parameter in the evaluation of CFD results. Thereby, a

Two biomass diameters are examined (1 mm and 5 mm). The smaller particle size can be achieved through a

reduction step. The larger particle size, which is somewhat higher than the firing, is achieved directly at the field when the collection of cardoon

Overall, several important operational parameters are unaffected by co-firing biomass at low thermal loading: the furnace exit temperature is only slightly increased, so there is no expectancy of intensifying slagging/fouling phenomena related to the

cenario. The total heat transfer to the furnace wall is likewise unaffected. CFD analysis suggests that a

firing conditions is a decrease of NOx emissions up to 10%, to the lower nitrogen content of the biomass fuel and the respective

mechanism for fuel NOx formation. This trend is well attested by literature and pilot but not by short term testing in the examined large scale boiler.

firing concerns the char burnout for lignite and biomass. UBC losses from the hopper are increased for lignite particles under co-firing, while the

particles exiting through the main outlet is largely unaffected. For the size is of outmost importance; particles with an equivalent

diameter of 5 mm do not fall through the hopper unless they enter through the lower main burner, but exhibit very low char burnouts despite increased residence times.

an equivalent diameter of 1 mm, exhibit very high char burnouts for all burner levels, despite being at least one size category larger than

firing of large biomass firing campaign at Kardia.

Particles entering the furnace through the lower main burner differ significantly in their trajectories compared to all other burner levels. The recirculation zone of the flow field

gion tends to increase the trajectories and residence time of several particles, which fall initially into the hopper region and then find their way in the upward current as they gradually loss weight. On the other hand, depending on

nd particle density, a number of particles leave the furnace from

Biomass particles that have undergone significant size reduction before entering the . Larger biomass particles,

which are not subjected to separate size reduction or for which current size reduction hopper and fly ash.

tly decreased due to the low fixed carbon content of the biomass particles, other issues may occur, such as

fly ash particles at heat exchange surfaces or problems in the he intensity of these

In conclusion, for the investigated boiler there appear to be two potential co-firing schemes, which should be further evaluated according to techno-economic criteria.



Date: 15.03.2013

The first concept ensures adequate biomass size reduction, which can then be mixed with the lignite stream. Combustion is ensured regardless of the burner level of biomass entry. The second concept does not rely so much on milling, although some size criteria must be Instead, a separate feeding system is used to inject the biomass at an optimum position for maximum burnout. Based on the above findings, such an injection point should be located between the lmore oil burner for biomass injection is such a possibility.


The boiler efficiency resulted not influenced by a biomass thermal share as low as 10%.

Mean values of the flue gas temperatures at various heights along the boiler, as well as after the ESPs, were measured. No significant changes were observed during co

The flue gas volume showed the composition, it resulted that:

- The oxygen content was almost constant and within the range 5demand hours, rising to more than 11% during the night. correlated to the corresponding decrease in load and to changes in

- The CO emissions, whichsignificant changes during for co

- The SO2 emissions fluctuateclear figure, with sporaremained much lower than the limit of 400 mg/Nmto changes of the CaO content in the ashFurthermore, decreaseversa can be observedgas, so that higher contents

- The influence of the cofiring and (458±32) mg/m³be important: agricultural waste influence the production of NOx during the thermal function of the excess air, which increases in lowcooling air for the burners not in operation.

- Dust emissions exhibited large variations during cochanges and ESP operation. A large decrease of dust emissions was observed upon firing of lignite with lower calcium content; this was accompanied by an increase of SO2 emissions, as discussed above.

Concluding, no negative effectsparameters were observed. Unburned materialgrindability also appears to remain the same, although a more intensive sampling should clarify the issue.

The only noticeable difference was an incardoon co-firing. The UBC resulted

From a technical point of view, olive kernel especially at the Kardia PP. For focusing on slagging/fouling, should be undertaken. Some technical modifications should also be implemented, e.g. construction of suitable storage area and fuel weighting for the exact determination of CO2 savings.



ncept ensures adequate biomass size reduction, which can then be mixed with the lignite stream. Combustion is ensured regardless of the burner level of biomass entry. The second concept does not rely so much on milling, although some size criteria must be fulfilled before biomass particles are injected in the boiler. Instead, a separate feeding system is used to inject the biomass at an optimum position for maximum burnout. Based on the above findings, such an injection point should be located between the lower and upper main burner. The retrofitting of one or more oil burner for biomass injection is such a possibility.



flue gas temperatures at various heights along the boiler, as well as after were measured. No significant changes were observed during co

only one small decrease of 2% during co-firingcomposition, it resulted that:

was almost constant and within the range 5-7% during the highrising to more than 11% during the night. This increase

correlated to the corresponding decrease in load and to changes in , which are an indication of the combustion efficiency, showed

significant changes during for co-firing. emissions fluctuated greatly for co-firing, while coal firing presented

clear figure, with sporadic peaks upwards. In all cases, however, SOremained much lower than the limit of 400 mg/Nm3. The fluctuations can be attributed to changes of the CaO content in the ash, which can capture SO

decreases in dust emissions concurring with SO2 ican be observed. In fact, SO2 influences the electrical conductivity of the

gas, so that higher contents improve the ESP performances. The influence of the co-firing on the NOx-emission was (490±10) m

±32) mg/m³ with co-firing. In this context the origin ofgricultural waste produced under application of fertili

influence the production of NOx during the thermal utilisation. Furthermore, NOx is a ess air, which increases in low-load operation caused by the

cooling air for the burners not in operation. Dust emissions exhibited large variations during co-firing, as a result of lignite quality

ESP operation. A large decrease of dust emissions was observed upon firing of lignite with lower calcium content; this was accompanied by an increase of

emissions, as discussed above.

o negative effects of biomass co-firing on load, emissions or other operational re observed. Unburned material content in the fly ash depending on the

grindability also appears to remain the same, although a more intensive sampling should

difference was an increase of UBC (and LOI) in the bottom ash during resulted nearly doubled compared to pure lignite combustion

From a technical point of view, olive kernel biomass is a promising candidate for coP. For a permanent application, a more intensive investigation,

focusing on slagging/fouling, should be undertaken. Some technical modifications should also be implemented, e.g. construction of suitable storage area and fuel weighting for the

savings.

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ncept ensures adequate biomass size reduction, which can then be mixed with the lignite stream. Combustion is ensured regardless of the burner level of biomass entry. The second concept does not rely so much on milling, although some

fulfilled before biomass particles are injected in the boiler. Instead, a separate feeding system is used to inject the biomass at an optimum position for maximum burnout. Based on the above findings, such an injection point

ower and upper main burner. The retrofitting of one or


flue gas temperatures at various heights along the boiler, as well as after were measured. No significant changes were observed during co-firing.

firing. With regard to

7% during the high-This increase can be

correlated to the corresponding decrease in load and to changes in the lignite quality. the combustion efficiency, showed no

ring, while coal firing presented a more however, SO2 emissions

fluctuations can be attributed SO2 and form CaSO4.

increases and vice influences the electrical conductivity of the flue

±10) mg/m³ without co-firing. In this context the origin of the biofuel may

ed under application of fertilisers may Furthermore, NOx is a

load operation caused by the

firing, as a result of lignite quality ESP operation. A large decrease of dust emissions was observed upon

firing of lignite with lower calcium content; this was accompanied by an increase of

ons or other operational fly ash depending on the

grindability also appears to remain the same, although a more intensive sampling should

) in the bottom ash during ed to pure lignite combustion.

is a promising candidate for co-firing, permanent application, a more intensive investigation,

focusing on slagging/fouling, should be undertaken. Some technical modifications should also be implemented, e.g. construction of suitable storage area and fuel weighting for the



Date: 15.03.2013


Fuel samples were collected and analysed in both cases of pure lignite and lignite with 10% cardoon. The representative ash components of the lignite/biomass mixture resulted in the range of the pure lignite, as well as the slagging behaviour and the ash melting temperature.

Therefore, no influence of cardoon coslagging behaviour in the boiler.


ESP performance

The ESP performance of the unit under coimpactor; fly ash samples were taken directly before and after the ESP at a flue gas temperature of about 180 °C. The dust content befor e the ESP was very high owing to the high ash content of lignite. Generally, the ESP efficiency was very high, around 95.5%; however, the dust concentration after the ESP as measured was also high. In addition, the particle sizes of the collected samples revealed the emission of fine particles (PM 2.5) and aerosols into the atmosphere.

Fly ash particles consist of coarse particulates, which represent the largest fraction by weight in the cascade impactor samples before and after the ESP. Generally, particles does not exceed 20 µfraction, which exhibit 30% by weight of the total of

As can be expected from the fuel ash composition, calcium is the dominant dust particles, regardless of their impactor, represent the larger weight fraction and are mainly composed of lime and silicates. In the fine fraction (< 1 µm) the higher sulphur concentas a result of the natural desulphurisK2SO4 were also more prevalent in the fine fraction.

The high alkali and chlorine content of cardoon in particular did not significant effect on the operation. Based on the findings of the measurement campaign, it appears that the relatively high sulfur content of lignite facilitated the which are characterised by higher melting poinpresent in very low concentrations in the deposits and as HCl in the gas phase; a possible mechanism for the fate of chloride is the reaction of gas phase HCl with lime in the fly ash and its retention in the fly ash particles.

Finally, no major impact of 10% cardoon biomass comeasurement campaign.


It should be noted that, apart from SOlimits of Directive 2010/75/EU (IED) continued operation of the power plant, extensive retrofitting and the installation of moreAPCDs are required.



Fuel samples were collected and analysed in both cases of pure lignite and lignite with 10% cardoon. The representative ash components of the lignite/biomass mixture resulted in the

as well as the slagging behaviour and the ash melting temperature.

Therefore, no influence of cardoon co-firing at 10% thermal share can be observed on the slagging behaviour in the boiler.


of the unit under co-firing operation was measured using a cascade impactor; fly ash samples were taken directly before and after the ESP at a flue gas temperature of about 180 °C. The dust content befor e the ESP was very high owing to the

of lignite. Generally, the ESP efficiency was very high, around 95.5%; however, the dust concentration after the ESP as measured was also high. In addition, the particle sizes of the collected samples revealed the emission of fine particles (PM 2.5) and erosols into the atmosphere.

particles consist of coarse particulates, which represent the largest fraction by weight in the cascade impactor samples before and after the ESP. Generally, the particles does not exceed 20 µm. Further, the UBC has been identified and the submicron fraction, which exhibit 30% by weight of the total of the cascade impactor dust sample.

As can be expected from the fuel ash composition, calcium is the dominant their size. Coarser particles, collected in the first stages of the

represent the larger weight fraction and are mainly composed of lime and silicates. µm) the higher sulphur concentration reveals the presence of CaSO

s a result of the natural desulphurisation of the flue gas. Iron and potassiumwere also more prevalent in the fine fraction.

The high alkali and chlorine content of cardoon in particular did not operation. Based on the findings of the measurement campaign, it

appears that the relatively high sulfur content of lignite facilitated the sulphed by higher melting points compared to alkali chlorides. Chlorine was

present in very low concentrations in the deposits and as HCl in the gas phase; a possible mechanism for the fate of chloride is the reaction of gas phase HCl with lime in the fly ash

ly ash particles.

Finally, no major impact of 10% cardoon biomass co-firing could be observed during the


It should be noted that, apart from SO2, the NOx and dust emission values are beyond the limits of Directive 2010/75/EU (IED) (12), which will come into force in 2016. Thus, for continued operation of the power plant, extensive retrofitting and the installation of more

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Fuel samples were collected and analysed in both cases of pure lignite and lignite with 10% cardoon. The representative ash components of the lignite/biomass mixture resulted in the

as well as the slagging behaviour and the ash melting temperature.

firing at 10% thermal share can be observed on the

firing operation was measured using a cascade impactor; fly ash samples were taken directly before and after the ESP at a flue gas temperature of about 180 °C. The dust content befor e the ESP was very high owing to the

of lignite. Generally, the ESP efficiency was very high, around 95.5%; however, the dust concentration after the ESP as measured was also high. In addition, the particle sizes of the collected samples revealed the emission of fine particles (PM 2.5) and

particles consist of coarse particulates, which represent the largest fraction by weight the size of the fly ash

has been identified and the submicron cascade impactor dust sample.

As can be expected from the fuel ash composition, calcium is the dominant specie of the size. Coarser particles, collected in the first stages of the

represent the larger weight fraction and are mainly composed of lime and silicates. ration reveals the presence of CaSO4,

he flue gas. Iron and potassium in the form of

The high alkali and chlorine content of cardoon in particular did not appear to have a operation. Based on the findings of the measurement campaign, it

sulphurisation of alkalis, ts compared to alkali chlorides. Chlorine was

present in very low concentrations in the deposits and as HCl in the gas phase; a possible mechanism for the fate of chloride is the reaction of gas phase HCl with lime in the fly ash

firing could be observed during the

, the NOx and dust emission values are beyond the , which will come into force in 2016. Thus, for

continued operation of the power plant, extensive retrofitting and the installation of more



Date: 15.03.2013


At Kardia PP, co-firing was tested plant is lignite from nearby lignite mines. relatively wide range for the ash chemical parameters havebiomass used for the tests is characterised by an ash content ranging frommass. The impact of co-firing firing of the biomass resultednormal lignite fuel diet.

As the investigated ashes from lignite are not covered in the fly ash standard for concrete and as the chemical composition of these ashematerial, as e.g. filling material, the physical properties have to be considered more intensively as well as the trace element concentration, especially for the leaching limit values.If the co-firing is combined with lignite cement and concrete may be obtained



ation of residues

was tested up to 10% cardoon thermal share. The main fuel is lignite from nearby lignite mines. A number of different lignite types are fired and

the ash chemical parameters have to be considered.biomass used for the tests is characterised by an ash content ranging from

firing on the ash quality was modest and, in general terms, ed in a more consistent ash chemical composition than for the

As the investigated ashes from lignite are not covered in the fly ash standard for concrete and as the chemical composition of these ashes is varying widely for a use as construction material, as e.g. filling material, the physical properties have to be considered more intensively as well as the trace element concentration, especially for the leaching limit values.

ned with lignite from a specific seam, also ash qualities for the use in cement and concrete may be obtained.

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. The main fuel of the A number of different lignite types are fired and a

to be considered. The cardoon biomass used for the tests is characterised by an ash content ranging from 9.5 to 14.5% by

modest and, in general terms, the co-chemical composition than for the

As the investigated ashes from lignite are not covered in the fly ash standard for concrete s is varying widely for a use as construction

material, as e.g. filling material, the physical properties have to be considered more intensively as well as the trace element concentration, especially for the leaching limit values.

ash qualities for the use in



Date: 15.03.2013

6.3 Fusina Power Plant (RDF co

Fusina Power Plant is located in area.

The power plant consists of four pulveri1 and 2), and two 320-MWel boilers (

Units 3 and 4 are tangentially Firing System (LNCFS) designed by Alstom Combustion Engineering (formerly ABB), a Selective Catalytic Reactor (SCR) for final NOx reduction, an electrostatic precipitator (ESP) and a flue gas desulphurization (FGD) system.vanadium pentoxide catalyst (Vfive fields in operation at maximum voltage. The FGD consists of a prelevels of sprinklers and a main scrubber with six levels of sprinklers fed by six suspencirculating pumps, five of which operate continuously.

In February 2009, it was authorisedFuel) up to 5% thermal inputwaste submitted to a bio-stabilisation process and delivered at the power plant as cylindrical pellets. The separately milled RDF is pneumatically injected into the pulverized coal pipelines before the primary air fans at the 2the basis of CFD simulations) as the best compromise to assure RDF complete burnand, in the meantime, avoid a huge increase of bottom ash production due to the fall of coarse RDF particles into the bottom hothe same previously used for PC.


The RDF has been successfully copermitting procedure to double RDF annual amountas a consequence, RDF has been increased up to 3 and 4. This is one of the first examples of an integrated management and thermal treatment of Municipal Solid Wastea plant for the RDF production, a RDF power plant and a section for compost production, in order to provide suitable treatment for every type of waste.products of the MSW management scheme are sh



Fusina Power Plant (RDF co -firing)

Fusina Power Plant is located in North-Eastern Italy, in the neighbourhood of

of four pulverised coal (PC) fired units: two 160-boilers (Units 3 and 4).

Units 3 and 4 are tangentially fired dry-bottom boilers, equipped with a Low NOx Concentric CFS) designed by Alstom Combustion Engineering (formerly ABB), a

Selective Catalytic Reactor (SCR) for final NOx reduction, an electrostatic precipitator (ESP) and a flue gas desulphurization (FGD) system. The SCR consists of three layers of

xide catalyst (V2O5 at 0.6 %). The ESP is equipped with 7 electric fields with five fields in operation at maximum voltage. The FGD consists of a prelevels of sprinklers and a main scrubber with six levels of sprinklers fed by six suspencirculating pumps, five of which operate continuously.

authorised to co-fire 70,000 tonnes/year of RDF (Refuse Derived input in two units. The RDF consists of separated municipal solid stabilisation process and delivered at the power plant as cylindrical

pellets. The separately milled RDF is pneumatically injected into the pulverized coal pipelines before the primary air fans at the 2nd and the 3rd level. This has been evaluated by ENEL (on the basis of CFD simulations) as the best compromise to assure RDF complete burnand, in the meantime, avoid a huge increase of bottom ash production due to the fall of coarse RDF particles into the bottom hopper. The nozzles used for the PC/RDF mixture are the same previously used for PC.


fully co-fired at Fusina PP since 2004. In February 2009 the permitting procedure to double RDF annual amount up to 70.000 tons was completed and, s a consequence, RDF has been increased up to 9t/h on each unit at full load

This is one of the first examples of an integrated management and thermal treatment of Municipal Solid Waste (MSW) in Italy. The MSW management system includes a plant for the RDF production, a RDF power plant and a section for compost production, in order to provide suitable treatment for every type of waste. The processes and the main products of the MSW management scheme are shown in Figure 8.

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in the neighbourhood of the Venice

-MWel boilers (Units

bottom boilers, equipped with a Low NOx Concentric CFS) designed by Alstom Combustion Engineering (formerly ABB), a

Selective Catalytic Reactor (SCR) for final NOx reduction, an electrostatic precipitator (ESP) The SCR consists of three layers of

at 0.6 %). The ESP is equipped with 7 electric fields with five fields in operation at maximum voltage. The FGD consists of a pre-scrubber with two levels of sprinklers and a main scrubber with six levels of sprinklers fed by six suspension

RDF (Refuse Derived . The RDF consists of separated municipal solid

stabilisation process and delivered at the power plant as cylindrical pellets. The separately milled RDF is pneumatically injected into the pulverized coal pipelines

level. This has been evaluated by ENEL (on the basis of CFD simulations) as the best compromise to assure RDF complete burn-out and, in the meantime, avoid a huge increase of bottom ash production due to the fall of

pper. The nozzles used for the PC/RDF mixture are

In February 2009 the 000 tons was completed and,

9t/h on each unit at full load on both units This is one of the first examples of an integrated management and thermal

e MSW management system includes a plant for the RDF production, a RDF power plant and a section for compost production, in

The processes and the main



Date: 15.03.2013

Figure 8

At Fusina, the RDF is received at the stationThe RDF is then fed out of the silos and conveyed through ferrous and nonseparation units to four high speed hammer mills.with time between hammer and screen changes, due to ervalues were reported:

The milled material is then conveyed pneumatically to Units 3 and 4, and in each case the RDF is injected directly into the pulverised coal primary air fans.

The RDF is co-fired through the burners in levels 2 and 3 only, i.e. two of the central burner levels. In this way, there are normally coal flames both above and below the burners cothe RDF to support the combustion process.employed and helps to maximise the combustion efficiency of the RDF.minimise the unburned fuel levels in both the furnace bottom ashes in the boiler hoppers andthe fly ashes collected in the electrostatic precipitator hoppers.



8: Scheme of the MSW management process.

At Fusina, the RDF is received at the station (Figure 9), and sent to two The RDF is then fed out of the silos and conveyed through ferrous and nonseparation units to four high speed hammer mills. The size grading of the milled RDF varied with time between hammer and screen changes, due to erosion, but the following ranges of

100% < 5 mm

50-70% < 2 mm

25-40% < 1 mm

15-30% < 0.5 mm

The milled material is then conveyed pneumatically to Units 3 and 4, and in each case the RDF is injected directly into the pulverised coal pipes, at a location just upstream of the

fired through the burners in levels 2 and 3 only, i.e. two of the central burner In this way, there are normally coal flames both above and below the burners co

DF to support the combustion process. This type of co-firing pattern is commonly employed and helps to maximise the combustion efficiency of the RDF.minimise the unburned fuel levels in both the furnace bottom ashes in the boiler hoppers andthe fly ashes collected in the electrostatic precipitator hoppers.

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large storage silos. The RDF is then fed out of the silos and conveyed through ferrous and non-ferrous metal

The size grading of the milled RDF varied osion, but the following ranges of

The milled material is then conveyed pneumatically to Units 3 and 4, and in each case the pipes, at a location just upstream of the

fired through the burners in levels 2 and 3 only, i.e. two of the central burner In this way, there are normally coal flames both above and below the burners co-firing

firing pattern is commonly employed and helps to maximise the combustion efficiency of the RDF. This helps to minimise the unburned fuel levels in both the furnace bottom ashes in the boiler hoppers and



Date: 15.03.2013

Figure

Separate injection system

A number of potential RDF injection configurations first phase of the work, after the validation of a model for the calculation of pressure drops on the existing feeding system, four different RDF separate injection configurations identified and the pressure drops were estimated. This study Computational Fluid Dynamiccode for three-dimensional simulation of combustion chambers, code has been extensively used combustion systems for industrial steam generators.experimental measurements (velocity, temperature and chIPSE code allows the simulation of both homogenous and heterogeneous combustion processes.

In order to evaluate the four different separate injection configurationperformance was calculated in terms of temperatcombustion chamber and fly and bottom ash.

The CFD simulations show no significant differences the boiler and the thermal fluxes at the walls.

Regarding the RDF residence permanence at 850 °C for at least 2 seconds. Based on the experienceconsidered appropriate for achieving a good burnout.

No significant improvement injustify the cost of the investment andimplemented for now.


As part of the activities plannedout at RDF co-firing shares of 0average unit load in the range 301co-firing on the boiler performance was negligible

There are no clear trends of the oxygen concentrationrate with the RDF co-firing level.

The measured flue gas temperatures at the heater inlet and outlet as well asno clear trends in the flue gas temperatures with the RDF cowith regards to the boiler convective section, factors nor in the heat absorption



Figure 9: RDF reception area at Fusina PP.

RDF injection configurations were investigated by CFD modelling. first phase of the work, after the validation of a model for the calculation of pressure drops on the existing feeding system, four different RDF separate injection configurations identified and the pressure drops as well as the auxiliary consumption for each configuration

study was carried out by means of the 3D-CFD (3Dynamics) code IPSE (Industrial Process Simulation Environment, a

dimensional simulation of combustion chambers, developed by ENEL).used for the analysis, the design and the process optimi

combustion systems for industrial steam generators. The code has been validated with experimental measurements (velocity, temperature and chemical species concentrations).IPSE code allows the simulation of both homogenous and heterogeneous combustion

In order to evaluate the four different separate injection configurationcalculated in terms of temperatures, thermal fluxes, residence time in

combustion chamber and fly and bottom ash.

The CFD simulations show no significant differences as for the average gas temperatures in he thermal fluxes at the walls.

Regarding the RDF residence time in the boiler, all configurations guarantee the flue gas permanence at 850 °C for at least 2 seconds. Based on the experience

d appropriate for achieving a good burnout.

No significant improvement in the boiler performance has been highlighted by this study to justify the cost of the investment and, therefore, dedicated RDF injection will not be


f the activities planned within the DEBCO project, a series of 11 tof 0-5% on a thermal basis (8.2% on a mass bas

in the range 301-307 MWel. It clearly resulted that the impact of the RDF firing on the boiler performance was negligible at the tested ratios.

the oxygen concentration in the flue gas nor offiring level.

The measured flue gas temperatures at the ECO inlet, at the SCR inlet and outlet, as well as at the chimney were within very close bands and there are

no clear trends in the flue gas temperatures with the RDF co-firing levels. This indicates thatwith regards to the boiler convective section, there were no major differences

heat absorption resulting at the tested RDF co-firing ratio

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by CFD modelling. In a first phase of the work, after the validation of a model for the calculation of pressure drops on the existing feeding system, four different RDF separate injection configurations were

tion for each configuration CFD (3-Dimension

) code IPSE (Industrial Process Simulation Environment, a veloped by ENEL). This process optimisation of

The code has been validated with emical species concentrations).

IPSE code allows the simulation of both homogenous and heterogeneous combustion

In order to evaluate the four different separate injection configurations, the boiler thermal fluxes, residence time in the

the average gas temperatures in

time in the boiler, all configurations guarantee the flue gas permanence at 850 °C for at least 2 seconds. Based on the experience, this value can be

has been highlighted by this study to dedicated RDF injection will not be

roject, a series of 11 tests was carried 8.2% on a mass basis) and at the

It clearly resulted that the impact of the RDF

nor of the flue gas flow

the SCR inlet and outlet, at the air at the chimney were within very close bands and there are

firing levels. This indicates that, there were no major differences in the fouling

ratios.



Date: 15.03.2013

The most reliable indicator of the heat absorption performance of the furnace is provided by the measured superheater spray flow rates, and it is clear from the measis no significant trend. This indicates that there is no evidence to suggest that the cothe RDF material had any significant impact on the furnace performance.

No clear variation of the total losses either appeared. gas loss, the moisture loss, the humidity the moisture content of the fuel, the flue gas oxygen concentration and the flue gas temperature at the air heater outlet.since no relevant data is available for the trial periods.

The NOx, O2 and CO concentrations in the flue gas were measured downstream the ECO with a 5-point grid, both on the left and the right ductcampaign. The UBC was determined in the chemistry laboratory in the fly ash samples collected in both ducts downstream the ECO.

From a general point of view, the performed analyses indicate no significant differences between the emission values in the only coal and in the RDF/coal cowith the same setting of the burner corner ports:

- The NOx emission is within the normal range of fluctuation experienced without cofiring.

- The difference of the steam consumption for the soot blower is negligible. - The CO values resulted always under the lawful limit. - The UBC in the ESP ash is within the range of the fluctuation experienced without co

firing.

The boiler temperature was measmeans of temperature controlled probes. The measurements were performed at different distances from the left wall and for different combustion settings. The temperature in the RDF/coal assets resulted always lower than in the pure coal ones (from 10 to 80 °C in the tested configurations). These differences are due to the blowing cycle frequency being usually higher in the co-firing assets and, thus, increasing the thermal dispersion through the boiler walls.


The slagging and fouling tendency campaigns.

Deposit samples were collected in two points of the boiler: the first one in the combustion chamber, at 28 m elevation (5one in the convective zone at 32 m elevation (6

The ash deposit was collected with proper probes and the Total Deposition Rate (TDR), which is as indication of the fo

The TDR at the 5th floor, where chiefly slagging occurs, resulted floor, where chiefly fouling occurs. Furthermore, the RDF/cby TDRs higher than in the pure coal configuration, both at the 5

Furthermore, the fly ash was sampled downstream concentration was determined. Higher values of potassium and sodium were obtained in the PC/RDF co-firing configurations. This result is related to the higher content of sodium, potassium, magnesium and calcium in the RDF than in the coal. Since these elements play also an important role in the ash melting temperature decrease, this evidence can bcorrelated to the slagging increase during the operation in the PC/RDF co

Some deposit was also dry-stone removed and analyfor the 6th floor, no remarkable differences in the main element concentrations



indicator of the heat absorption performance of the furnace is provided by the measured superheater spray flow rates, and it is clear from the measured data that there is no significant trend. This indicates that there is no evidence to suggest that the cothe RDF material had any significant impact on the furnace performance.

variation of the total losses either appeared. They were estimated including the dry gas loss, the moisture loss, the humidity loss and the R&U losses, and dependthe moisture content of the fuel, the flue gas oxygen concentration and the flue gas temperature at the air heater outlet. On the contrary, the UBC loss could not be included

available for the trial periods.

and CO concentrations in the flue gas were measured downstream the ECO point grid, both on the left and the right duct during a dedic. The UBC was determined in the chemistry laboratory in the fly ash samples

collected in both ducts downstream the ECO.

From a general point of view, the performed analyses indicate no significant differences values in the only coal and in the RDF/coal co-firing configurations

with the same setting of the burner corner ports:

The NOx emission is within the normal range of fluctuation experienced without co

The difference of the steam consumption for the soot blower is negligible. The CO values resulted always under the lawful limit.

in the ESP ash is within the range of the fluctuation experienced without co

The boiler temperature was measured in the super-heating area at the 6means of temperature controlled probes. The measurements were performed at different distances from the left wall and for different combustion settings. The temperature in the

ed always lower than in the pure coal ones (from 10 to 80 °C in the tested configurations). These differences are due to the blowing cycle frequency being

firing assets and, thus, increasing the thermal dispersion through the

The slagging and fouling tendency was evaluated with appropriate short-term measurements

Deposit samples were collected in two points of the boiler: the first one in the combustion chamber, at 28 m elevation (5th floor), on the front wall close to the left corner, the second one in the convective zone at 32 m elevation (6th floor), on the left wall.

The ash deposit was collected with proper probes and the Total Deposition Rate (TDR), which is as indication of the fouling and slagging tendency, has been calculated.

floor, where chiefly slagging occurs, resulted higherfloor, where chiefly fouling occurs. Furthermore, the RDF/coal configuration is characteris

higher than in the pure coal configuration, both at the 5th and at the 6

Furthermore, the fly ash was sampled downstream of the ECO and the main element concentration was determined. Higher values of potassium and sodium were obtained in the

firing configurations. This result is related to the higher content of sodium, potassium, magnesium and calcium in the RDF than in the coal. Since these elements play also an important role in the ash melting temperature decrease, this evidence can bcorrelated to the slagging increase during the operation in the PC/RDF co-

stone removed and analysed with the SEM/EDS technique. As floor, no remarkable differences in the main element concentrations

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indicator of the heat absorption performance of the furnace is provided by ured data that there

is no significant trend. This indicates that there is no evidence to suggest that the co-firing of

estimated including the dry depend principally on

the moisture content of the fuel, the flue gas oxygen concentration and the flue gas ntrary, the UBC loss could not be included

and CO concentrations in the flue gas were measured downstream the ECO ated measurement

. The UBC was determined in the chemistry laboratory in the fly ash samples

From a general point of view, the performed analyses indicate no significant differences firing configurations

The NOx emission is within the normal range of fluctuation experienced without co-

The difference of the steam consumption for the soot blower is negligible.

in the ESP ash is within the range of the fluctuation experienced without co-

heating area at the 6th floor (32 m) by means of temperature controlled probes. The measurements were performed at different distances from the left wall and for different combustion settings. The temperature in the

ed always lower than in the pure coal ones (from 10 to 80 °C in the tested configurations). These differences are due to the blowing cycle frequency being

firing assets and, thus, increasing the thermal dispersion through the

term measurements

Deposit samples were collected in two points of the boiler: the first one in the combustion oor), on the front wall close to the left corner, the second

The ash deposit was collected with proper probes and the Total Deposition Rate (TDR), uling and slagging tendency, has been calculated.

higher the one at the 6th oal configuration is characterised

and at the 6th floor.

the ECO and the main element concentration was determined. Higher values of potassium and sodium were obtained in the

firing configurations. This result is related to the higher content of sodium, potassium, magnesium and calcium in the RDF than in the coal. Since these elements play also an important role in the ash melting temperature decrease, this evidence can be

-firing setting.

ed with the SEM/EDS technique. As floor, no remarkable differences in the main element concentrations resulted



Date: 15.03.2013

between PC firing and PC/RDF cosamples highlighted an increase in Na

Corrosion

Four long-term (up to 5700 hours of fire) corrosion monitoring campexposing samples of different materials (16Mo3 and A105 for the membrane wall of the combustion chamber, AISI 347 and AISI Super 304H for the convective pass) at different temperatures (current operating conditions and Ultra Super CrThe results are summarised in

Table 15

Material Temperature [°C]

A105 440

AISI 347H 570

16Mo3 450 (USC simulation)

AISI 304H 630 (USC simulation)

The materials exposed in the convective pass present a negligible corrosion attack. Postexposure metallographic analyses confirmed this result.

On the contrary, with regard to the combustion chamber, coincrease the corrosion grade compared resulted higher near the PC/RDF nozzles, and lower near the PC nozzles. The corgrade increase can be ascribed to the higher chlorine content in the proximity of RDF injection. The corrosion grade results generally higher for 16Mo3 than for A105.


SCR performance

At the time of the measurements, the44,000, 16,000 and 80,000 hours.

The DeNOx efficiency ranged from 42 to 67% with no significant correlation with the RDF thermal input. As for Hg, the speciation varied across the SCR reactor, with an incionic phase (Hg2+). The oxidizing reaction was promoted by the presence of the catalyst and the oxidation efficiency varied between 40% and 83% according to the RDF thermal input. In particular, Hg0 oxidation efficiency increased with the RDF perchigher HCl concentration in the cooxidation. ESP performance

Particulate and micro-pollutants (Hg and heavy metals) are removed in the ESP, consisting of 7 electric fields. Heavy metals, due to the low volatility, are present in the bottom ash (removed in the boiler hopper) and in the fly ash (removed in the ESP). The highly volatile selenium is an exception and is mainly present in the gas phase and in the subparticles.

The fly ash resulted quantitatively removed in the ESP with outlet concentration values two orders of magnitude lower than at the inlet and widely below the lawful limit with areduction efficiency.



between PC firing and PC/RDF co-firing. On the contrary, the analyses of the 5samples highlighted an increase in Na2O, CaO and K2O percentages during co

hours of fire) corrosion monitoring campaigns were carried out exposing samples of different materials (16Mo3 and A105 for the membrane wall of the combustion chamber, AISI 347 and AISI Super 304H for the convective pass) at different temperatures (current operating conditions and Ultra Super Critical steam cycle simulation). The results are summarised in Table 15.

15: Long-term corrosion monitoring campaign.

Temperature [°C] Position Corrosion

combustion chamber depending on probe position

convective pass negligible

450 (USC simulation) combustion chamber depending on probe position

630 (USC simulation) convective pass negligible

The materials exposed in the convective pass present a negligible corrosion attack. Postexposure metallographic analyses confirmed this result.

On the contrary, with regard to the combustion chamber, co-firing operation results to increase the corrosion grade compared with coal operation. In fact, the probe consumption resulted higher near the PC/RDF nozzles, and lower near the PC nozzles. The corgrade increase can be ascribed to the higher chlorine content in the proximity of RDF injection. The corrosion grade results generally higher for 16Mo3 than for A105.


At the time of the measurements, the SCR catalyst (V2O5 0.6%) had been in operation for 000 hours.

The DeNOx efficiency ranged from 42 to 67% with no significant correlation with the RDF thermal input. As for Hg, the speciation varied across the SCR reactor, with an inc

). The oxidizing reaction was promoted by the presence of the catalyst and the oxidation efficiency varied between 40% and 83% according to the RDF thermal input. In

oxidation efficiency increased with the RDF percentage. The reason is the higher HCl concentration in the co-firing flue gas, which has an activating effect on Hg

pollutants (Hg and heavy metals) are removed in the ESP, consisting Heavy metals, due to the low volatility, are present in the bottom ash

(removed in the boiler hopper) and in the fly ash (removed in the ESP). The highly volatile selenium is an exception and is mainly present in the gas phase and in the sub

The fly ash resulted quantitatively removed in the ESP with outlet concentration values two orders of magnitude lower than at the inlet and widely below the lawful limit with a

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firing. On the contrary, the analyses of the 5th-floor O percentages during co-firing.

aigns were carried out exposing samples of different materials (16Mo3 and A105 for the membrane wall of the combustion chamber, AISI 347 and AISI Super 304H for the convective pass) at different

itical steam cycle simulation).

Corrosion

depending on probe position

negligible

depending on probe position

negligible

The materials exposed in the convective pass present a negligible corrosion attack. Post-

firing operation results to coal operation. In fact, the probe consumption

resulted higher near the PC/RDF nozzles, and lower near the PC nozzles. The corrosion grade increase can be ascribed to the higher chlorine content in the proximity of RDF injection. The corrosion grade results generally higher for 16Mo3 than for A105.

%) had been in operation for

The DeNOx efficiency ranged from 42 to 67% with no significant correlation with the RDF thermal input. As for Hg, the speciation varied across the SCR reactor, with an increase of

). The oxidizing reaction was promoted by the presence of the catalyst and the oxidation efficiency varied between 40% and 83% according to the RDF thermal input. In

entage. The reason is the firing flue gas, which has an activating effect on Hg0

pollutants (Hg and heavy metals) are removed in the ESP, consisting Heavy metals, due to the low volatility, are present in the bottom ash

(removed in the boiler hopper) and in the fly ash (removed in the ESP). The highly volatile selenium is an exception and is mainly present in the gas phase and in the sub-micron

The fly ash resulted quantitatively removed in the ESP with outlet concentration values two orders of magnitude lower than at the inlet and widely below the lawful limit with a 99.9% of



Date: 15.03.2013

As for mercury, about 60% of the amount leaving the boiler was removed with fly ash in the ESP; as for the trace metals, except selenium, they were removed with an efficiency between 70 and 90%.


PC/RDF co-firing up to 5% RDF themicro-pollutant emissions of the PC power plant. The measurement highlighted values fairly below the maximum lawful limits.

As for the micro-pollutants, the removal efficiency resulted about 90% fortrace metals, nearly 100% for particulate with diameter d > 2.5 µm. The mercury emission showed no problem in meeting the limit value requested by the IED for coThe efficiency in dust removal of ESP/FGD is comparable

6.3.4 Utilisation

The fly ashes of Fusina PP were impact of RDF on their compos

The RDF ash composition is dominated by silica, alumina and the mineral fillers in paper, and there are signifi

Compared with pure bituminous coal combustion, t5% RDF co-firing showed a slight increase inFe, Zn), alkalis and chlorides. the future requirements for the application rules.

The main conclusion of the fly ash characteriinput has slightly increased tcomposition and, therefore, the use as concr(European Technical Approval)



As for mercury, about 60% of the amount leaving the boiler was removed with fly ash in the trace metals, except selenium, they were removed with an efficiency


firing up to 5% RDF thermal input resulted not to affect the macropollutant emissions of the PC power plant. The measurement highlighted values fairly

below the maximum lawful limits.

pollutants, the removal efficiency resulted about 90% fortrace metals, nearly 100% for particulate with diameter d > 2.5 µm. The mercury emission showed no problem in meeting the limit value requested by the IED for coThe efficiency in dust removal of ESP/FGD is comparable to the best available technologies.

Utilisation of residues

Fusina PP were characterised in the long term in order to evaluate the composition and quality.

The RDF ash composition is dominated by silica, alumina and lime, largely associated with the mineral fillers in paper, and there are significant levels of potash and soda.

Compared with pure bituminous coal combustion, the analyses of the ashes sampled duringa slight increase in the concentrations of same trace elements

s. The trace elements need to be taken into accountthe product standards as well as in light of the

clusion of the fly ash characterisation is that RDF co-firing up toinput has slightly increased the trace element contents but not affected

the use as concrete addition could be possible provided aEuropean Technical Approval) for co-firing of RDF is granted.

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As for mercury, about 60% of the amount leaving the boiler was removed with fly ash in the trace metals, except selenium, they were removed with an efficiency

rmal input resulted not to affect the macro-pollutant and pollutant emissions of the PC power plant. The measurement highlighted values fairly

pollutants, the removal efficiency resulted about 90% for Hg, 99% for total trace metals, nearly 100% for particulate with diameter d > 2.5 µm. The mercury emission showed no problem in meeting the limit value requested by the IED for co-firing with waste.

to the best available technologies.

in order to evaluate the

lime, largely associated with cant levels of potash and soda.

the ashes sampled during trations of same trace elements (Cu,

elements need to be taken into account in light of in light of the existing national

firing up to 5% thermal contents but not affected the main oxide

ete addition could be possible provided an ETA



Date: 15.03.2013

6.4 Dorog and Má tra Power

The Dorog Power Plant, located in Hungary,district, process steam and electrand 1 boiler (Unit 4) is on reserve.

Units 3 and 4 are tangential fired lignite boilers with a nominal steam capacity of 50 t/h, 430 °C and 35 bar abs. The design coal was of low heating value (12 content (25-30%). The boiler produces steam by having natural circulation in the water tube system. Units 5 and 6 originallfire natural gas.

To increase combustion efficiency of lignite type with heating value of 17modifications had been necessary to meet the new operating conditions. Some more fan power was needed, however foheating value, which reduces the energy demand of grinding. Experiments showed that eventually less motor power was necessary by about 10%. In order to reduce recirculation system was installed at the bottom of the furnace by which the fallcan be recycled (external fuel recirculation (EFR) system). The concept of EFR was successfully proven and after modification and using higher heating value coal, the boiler efficiency increased from 81% to 87%.

The 836-MW Mátra power station is the largest lignite fired plant in Hungary. Lignite of 7MJ/kg heating value from a local open mine is supplied to belt conveying system in a yearly quan540 °C) is 640 t/h for three units and co-firing tests and trials had been carried out(sludge) and agricultural wastes. By the year of 2007 already 7% of the total boiler heat input was supplied by biomass. In 2008, a biomass feeding station of 1 million toncapacity was built near the coal yard to mix biomass of 12lignite. The biomass consists of woodstraw.


Firing of biomass started in 2007retrofitted to allow the biomass new and larger electric motors were installed to the mills and new burner configuration was applied. In addition, an External material from the furnace bottom upstream of the mills. UBC in the bottom ash could be

Two ways are possible to overcomeplants. One is building a new feeding facility for very expensive solution and power pelletising the material near the source of production. In the latter case, testing activities at Dorog PP, investment at the plant. However,price of the pellets, as of now, is higher than that of wood

Biomass/coal co-firing was tested at Dorog PP at 50% biomass thermal input. The biomass fuel consisted in a mixture of bran.

The tests were performed at 85% boiler load. Two separate fuel linfor the pellets, so they did not mix before the flame. One bunker fed two biomass mills and



tra Power Plants (agricultural biomass co

, located in Hungary, is a co-generation plant producing hot water for district, process steam and electric energy. There are 3 operating boiler (

nit 4) is on reserve.

Units 3 and 4 are tangential fired lignite boilers with a nominal steam capacity of 50 t/h, 430 . The design coal was of low heating value (12 MJ/kg) and of high ash

30%). The boiler produces steam by having natural circulation in the water tube system. Units 5 and 6 originally were designed identically to Unit 4, but later redesigned to

iency of Unit 3, in 2006 the low grade coal was changed for a lignite type with heating value of 17-20 MJ/kg and ash content of 10modifications had been necessary to meet the new operating conditions. Some more fan power was needed, however for a given boiler load, less fuel is necessary due to its higher heating value, which reduces the energy demand of grinding. Experiments showed that eventually less motor power was necessary by about 10%. In order to reduce

m was installed at the bottom of the furnace by which the fallcan be recycled (external fuel recirculation (EFR) system). The concept of EFR was successfully proven and after modification and using higher heating value coal, the boiler

ency increased from 81% to 87%.

tation is the largest lignite fired plant in Hungary. Lignite of 7MJ/kg heating value from a local open mine is supplied to five units through a sophisticated belt conveying system in a yearly quantity of 7 million tonnes. The steam capacity

three units and 320 t/h for the other two. Prior to 2005, only sfiring tests and trials had been carried out with residues of food industry, municipal wastes

e) and agricultural wastes. By the year of 2007 already 7% of the total boiler heat input was supplied by biomass. In 2008, a biomass feeding station of 1 million toncapacity was built near the coal yard to mix biomass of 12-13 MJ/kg heating valuelignite. The biomass consists of wood-chips, saw-dust, agricultural by-products such as cut


Firing of biomass started in 2007, when two fuel lines (fuel bunker, mills and burners) were biomass transportation – mainly wood-chips and saw

ew and larger electric motors were installed to the mills and new burner configuration was xternal Fuel Recirculation (EFR) system was built to recycle solid bottom upstream of the mills. In this way, the heat loss due to the

in the bottom ash could be reduced.

to overcome the feeding problems of agricultural bynew feeding facility for biomass handling and feeding, which is and power utilities are reluctant to invest, while

the material near the source of production. In the latter case, activities at Dorog PP, the technology is capable of feeding pellets without major

. However, extra costs are due to the pellet production plant, and the pellets, as of now, is higher than that of wood-chips and saw-dus

firing was tested at Dorog PP at 50% biomass thermal input. The biomass fuel consisted in a mixture of barley straw pellets an wood-chips, sunflower hull and wheat

The tests were performed at 85% boiler load. Two separate fuel lines were used for coal and so they did not mix before the flame. One bunker fed two biomass mills and

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(agricultural biomass co -firing)

generation plant producing hot water for ic energy. There are 3 operating boiler (Units 3, 5 and 6)

Units 3 and 4 are tangential fired lignite boilers with a nominal steam capacity of 50 t/h, 430 MJ/kg) and of high ash

30%). The boiler produces steam by having natural circulation in the water tube nit 4, but later redesigned to

, in 2006 the low grade coal was changed for a MJ/kg and ash content of 10-15%. Boiler

modifications had been necessary to meet the new operating conditions. Some more fan r a given boiler load, less fuel is necessary due to its higher

heating value, which reduces the energy demand of grinding. Experiments showed that eventually less motor power was necessary by about 10%. In order to reduce UBC losses, a

m was installed at the bottom of the furnace by which the fall-out material can be recycled (external fuel recirculation (EFR) system). The concept of EFR was successfully proven and after modification and using higher heating value coal, the boiler

tation is the largest lignite fired plant in Hungary. Lignite of 7-8 through a sophisticated

The steam capacity (165 bar, Prior to 2005, only short-term

residues of food industry, municipal wastes e) and agricultural wastes. By the year of 2007 already 7% of the total boiler heat input

was supplied by biomass. In 2008, a biomass feeding station of 1 million tonnes/year 13 MJ/kg heating value to the

products such as cut

when two fuel lines (fuel bunker, mills and burners) were chips and saw-dust. Basically,

ew and larger electric motors were installed to the mills and new burner configuration was ecirculation (EFR) system was built to recycle solid

In this way, the heat loss due to the

eding problems of agricultural by-products to PC handling and feeding, which is a

while the other is the material near the source of production. In the latter case, also used for the

pellets without major the pellet production plant, and the

dust.

firing was tested at Dorog PP at 50% biomass thermal input. The biomass chips, sunflower hull and wheat

es were used for coal and so they did not mix before the flame. One bunker fed two biomass mills and



Date: 15.03.2013

one bunker one coal mill. The biomass feeding was not always continuous due to the inhomogeneous mixture. Woodplugging, mechanical agitation of the material was necessary

Figure 10


During the testing activities, the producing fresh steam at relatively low superthe nominal steam temperatures was observed. The flue gas temperature at the boiler exit was in the design range (150 °C).

The NOx concentration resulted higher than with only coal and some combustion optimisation is needed. Slagging and fouling was not ngas temperatures and to the careful selection of biomass with high ash initial deformation temperature. By now, the biomass co

Co-firing tests resulted successful alsdust was burned with lignite in a heat ratio of 10% in boilers designed for combination of tangential and grate combustion.



one bunker one coal mill. The biomass feeding was not always continuous due to the inhomogeneous mixture. Wood-chips tended to form craters in the bunker and for avoiding plugging, mechanical agitation of the material was necessary.

10: Dorog PP fuel handling and feeding system.


he risk of ash deposition and corrosion was simply minimised by producing fresh steam at relatively low super-heating temperature. No problem the nominal steam temperatures was observed. The flue gas temperature at the boiler exit was in the design range (150 °C).

The NOx concentration resulted higher than with only coal and some combustion optimisation is needed. Slagging and fouling was not noticed thanks to the low furnace flue

the careful selection of biomass with high ash initial deformation the biomass co-firing has become a common technique at this plant.

firing tests resulted successful also at Mátra PP, where a mixture of woodith lignite in a heat ratio of 10% in boilers designed for

combination of tangential and grate combustion.

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one bunker one coal mill. The biomass feeding was not always continuous due to the s in the bunker and for avoiding

of ash deposition and corrosion was simply minimised by No problem in reaching

the nominal steam temperatures was observed. The flue gas temperature at the boiler exit

The NOx concentration resulted higher than with only coal and some combustion the low furnace flue

the careful selection of biomass with high ash initial deformation firing has become a common technique at this plant.

ixture of wood-chips and saw-ith lignite in a heat ratio of 10% in boilers designed for PC with the



Date: 15.03.2013

6.5 Rokita (biomass co

PCC Rokita SA is a combined heat and Particular focus was put on limitations and requirementsfeeding system up to 50% and to identify major limitations and risks on the combustion technology, boiler slagging/foulirape seed and liquid biomass-

Boiler characteristics:

Steam capacity: 130 t/h

Steam parameters: 540 °C; 9.

Firing mode: Tangential with zonal combustion

Fuel preparation: 3 Fan-mills

Boiler operation: Co-generation of steam and electricity (100

Main fuel: Hard coal of 19

Biomass fuel: rape waste

Boiler efficiency: 83-85%

Figure 11: The location and arrangement of burners in PC OPmeasurements level by suction pyrometry probe

The most remarkable results are

- Decrease of UBC in the - NOx emission drop from 500

nitrogen in the biomass- Small increase of SO2 - The operational parameters were kept stable- Grinding blend does no- No problem occurred with regard to fouling and slagging.



(biomass co -firing)

ined heat and power plant with 36% biomass thermal input. on limitations and requirements to upgrade the biomass milling and

feeding system up to 50% and to identify major limitations and risks on the combustion technology, boiler slagging/fouling and operation. Beside wood, agriculture by

-crude glycerol and SRF were used.

°C; 9. 6 MPa

Tangential with zonal combustion

mills

generation of steam and electricity (100 MWth, 8

Hard coal of 19-25 MJ/kg LHV

rape waste (36% thermal input)

location and arrangement of burners in PC OP-130 boiler and temperature measurements level by suction pyrometry probe.

are:

the ash NOx emission drop from 500 mg/m³ to 300 mg/m³ in spite of the high content of

biomass emission ( sulphur content in rape waste and crude glycerol)

The operational parameters were kept stable not cause big problems with separation of bioma

No problem occurred with regard to fouling and slagging.

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power plant with 36% biomass thermal input. to upgrade the biomass milling and

feeding system up to 50% and to identify major limitations and risks on the combustion ng and operation. Beside wood, agriculture by-products as

MWel)

130 boiler and temperature

mg/m³ in spite of the high content of

emission ( sulphur content in rape waste and crude glycerol)

t cause big problems with separation of biomass in fan mill



Date: 15.03.2013

7 Appendix B - New In the present Appendix B performed by the DEBCO Partners

7.1 Erosion and corrosion

RSE performed erosion and corrosion laboratory tests on some selected materials, simulating operation both in cocycle. Six different materials were selected: the steel 347H and stalloy Inconel 740 and R156 (materials candidate for USC operprojects), Ni-base alloy Inconel 625 and Sanicro 28 (currently used for corrosion protection in harsh environments). The samples temperature wthe convective bundle tubes in USC power plants; the gas composition on the tests was that of the convective pass of a power plant, as indicated by calculations. Two erosion tests and two 1000 h corrosion tests were carried out in 2009

The main results of this research are the following:

- RSE developed an innovative erosion test rig (see Figuresamples of material at high temperature (up to 750°C)

Figure 12

- Erosion tests were performed at different powder (90° and 30°) and at different erosive veloc ity. The ranking of erosion resistance of the tested materials is reported in Figwhich is more critical angle for erosion attack, at three erosive velocities (42 m/s, 77 m/s and 93 m/s). The steel AISI 410 was also included in the tests as reference material, because is normally considered to have a good erosion resistance. At the lower erosive velocity, erosion rate values were found for steels S304, 347H and Niwhile the steel R156 sof AISI 410.

Air preheating andfinal heating

Erosivefeeder



New findings the key findings of the research and development activities

performed by the DEBCO Partners are summarised.

Erosion and corrosion laboratory tests

RSE performed erosion and corrosion laboratory tests on some selected materials, simulating operation both in co-firing arrangement and in Ultra Super Critical (USC) steam

Six different materials were selected: the steel 347H and steel Super 304H, Nialloy Inconel 740 and R156 (materials candidate for USC operation as indicated by some EU

base alloy Inconel 625 and Sanicro 28 (currently used for corrosion protection in harsh environments). The samples temperature was set to 630°C, which is a typical value of the convective bundle tubes in USC power plants; the gas composition on the tests was that of the convective pass of a power plant, as indicated by calculations. Two erosion tests and

were carried out in 2009-2011.

The main results of this research are the following:

nnovative erosion test rig (see Figure 12) able to characterisamples of material at high temperature (up to 750°C).

12: Innovative erosion test rig developed by RSE.

Erosion tests were performed at different Angles Of Impact (AOI) of the erosive powder (90° and 30°) and at different erosive veloc ity. The ranking of erosion

ted materials is reported in Figure 13 in the case of AOIwhich is more critical angle for erosion attack, at three erosive velocities (42 m/s, 77 m/s and 93 m/s). The steel AISI 410 was also included in the tests as reference

normally considered to have a good erosion resistance. At the the highest erosive rate is showed by alloy IN625, intermediate

erosion rate values were found for steels S304, 347H and Ni-base alloy Inconel 740, while the steel R156 shows the highest erosion resistance, which is close to that one

Air preheating andfinal heating

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he key findings of the research and development activities

RSE performed erosion and corrosion laboratory tests on some selected materials, er Critical (USC) steam

eel Super 304H, Ni-base ation as indicated by some EU

base alloy Inconel 625 and Sanicro 28 (currently used for corrosion protection in as set to 630°C, which is a typical value of

the convective bundle tubes in USC power plants; the gas composition on the tests was that of the convective pass of a power plant, as indicated by calculations. Two erosion tests and

) able to characterise the

mpact (AOI) of the erosive powder (90° and 30°) and at different erosive veloc ity. The ranking of erosion

in the case of AOI = 30°, which is more critical angle for erosion attack, at three erosive velocities (42 m/s, 77 m/s and 93 m/s). The steel AISI 410 was also included in the tests as reference

normally considered to have a good erosion resistance. At the the highest erosive rate is showed by alloy IN625, intermediate

base alloy Inconel 740, hows the highest erosion resistance, which is close to that one

Inconel Y-shapedVenturi erosivenozzle

Rotating disks forerosive speedmeasurement

Sample holder(0° and 45°)up to 800 °C



Date: 15.03.2013

Figure 13: Comparison of

- By these test results it was possible to estimate the material consumptions at the USC temperature of 630conditions of the convective pass of a density = 6 g/m3, ash estimation.

Table 16: Erosion rate estimation

IN740, SAN28, AISI

AISI S304H



Comparison of the erosion rates of the tested materials

By these test results it was possible to estimate the material consumptions at the USC temperature of 630 °C after 8000 hours of fire considering the real operationconditions of the convective pass of a PP (fly ash velocity = 10 m/s, AOI

granulometry d50 = 90 µm). Table 16 reports the results of this

Erosion rate estimation in co-firing + USC steam cycle conditions

Material mm / 8000 hours of fire (±10% acc.)

AISI 410 0.22 (reference material)

R156 0.24

IN740, SAN28, AISI 347H 0.26

AISI S304H 0.29

IN625 0.30

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erosion rates of the tested materials

By these test results it was possible to estimate the material consumptions at the considering the real operational

m/s, AOI = 30°, ash reports the results of this

SC steam cycle conditions.



Date: 15.03.2013

Comparing these estimations erosion/corrosion in energy plants, reported in Tabletested materials present a “significant” grade of consumption:the acceptance limit of 0.2 mma moderate but higher consumption, while the worst performance is for IN625 and the steel S304H.

Table 17: Ranking

7.2 Large- scale corrosion monitoring

Corrosion measurements wereRodenhuize PP, Unit 4, located at 43 m. A temperature controlled probe was used to check the corrosion mechanisms of testcorrosion samples with the deposit ash layer was embedded with epoxy for fixing the depositions for further preparation steps. To get an overview of the windward and lee a dry way and afterwards embedded identify the existing corrosion mechanismscomplete the preparation, all corrosion samples for each material were grinded and polished with appropriate abrasive papers and polishing cloths.

The gas temperature at the measurement point was on average between 1100biomass wood had a very low ash content, but relatively high contents of potassium and calcium. Calcium is able to build hard deposits on to clean. The chlorine content was very low in the wood.

The composition of the materials that were exposed is listed in standard material designed for super heaters up to 500designed for temperatures ustrength and oxidation resistance, along with an excellent resistance to a wide range of corrosive environments.

Corrosion/erosion rate

nm/h

<25*

25-50

50-100

100-200

>200

*25 nm/h is the conventional limit of acceptance



Comparing these estimations with the classification of the seriousness of the energy plants, reported in Table 17, we can conclude that all

gnificant” grade of consumption: the steel R156 is very close to acceptance limit of 0.2 mm / 8000 h of fire, the steel AISI 347H, IN740 and SAN 28 have

a moderate but higher consumption, while the worst performance is for IN625 and the steel

anking of the erosion/corrosion seriousness in PPs.

scale corrosion monitoring of pure wood- dust firing

were performed by USTUTT (IFK) at the super, Unit 4, located at 43 m. A temperature controlled probe was used to check

corrosion mechanisms of tested materials. After an exposure time of 90 hours, the corrosion samples with the deposit ash layer were removed. The surface area of the samples

embedded with epoxy for fixing the depositions for further preparation steps. To get an the windward and lee sides of the materials, rings were cut into cross sections in

a dry way and afterwards embedded one more time in a SEM adequate round identify the existing corrosion mechanisms, SEM-EDX was the method of choice. To complete the preparation, all corrosion samples for each material were grinded and polished with appropriate abrasive papers and polishing cloths.

at the measurement point was on average between 1100biomass wood had a very low ash content, but relatively high contents of potassium and calcium. Calcium is able to build hard deposits on the super-heater pipes, which are difficult

n. The chlorine content was very low in the wood.

The composition of the materials that were exposed is listed in Table 18standard material designed for super heaters up to 500-550°C. The Ni- based material was designed for temperatures up to 650-800°C and is characterised bystrength and oxidation resistance, along with an excellent resistance to a wide range of

Corrosion/erosion rate Classification

nm/h mm/y @ 8000 h/y

(fc=91%)

* <0.2 normal/tolerable

50 0.2-0.4 significant

100 0.4-0.8 serious

200 0.8-1.6 very serious

>200 >1.6 catastrophic

*25 nm/h is the conventional limit of acceptance

D7.10

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the classification of the seriousness of the , we can conclude that all of the

the steel R156 is very close to 8000 h of fire, the steel AISI 347H, IN740 and SAN 28 have

a moderate but higher consumption, while the worst performance is for IN625 and the steel

PPs.

dust firing

(IFK) at the super-heater area of , Unit 4, located at 43 m. A temperature controlled probe was used to check

exposure time of 90 hours, the re removed. The surface area of the samples

embedded with epoxy for fixing the depositions for further preparation steps. To get an sides of the materials, rings were cut into cross sections in

time in a SEM adequate round form. To s the method of choice. To

complete the preparation, all corrosion samples for each material were grinded and polished

at the measurement point was on average between 1100-1200 °C. The biomass wood had a very low ash content, but relatively high contents of potassium and

heater pipes, which are difficult

e 18. The ferrite is a based material was

is characterised by high-temperature strength and oxidation resistance, along with an excellent resistance to a wide range of



Date: 15.03.2013

Table 18:

Steel Cr [%]

Ferrite

Alloy 617 (Ni-based)

The Figure 14 shows the results of the nice oxide scale of about 30 µm thickness at formed before the K and Cl hit the material surface. No indication of Clwas detected. Above the KCl border, loose particles build the deposit. The particles show a loose structure, which means

Figure 14: SEM-BSE pictures of the ferritic sample after

The Ni-based alloy shows a typical twoabove (Figure 15). Differently to the ferrite at lower temperaturestructure where K and Cl are spread homogeneousproblematic for the cleaning system.

Figure 15: SEM-EDX element mappings of the Alloy 617 after



Alloying composition of the exposed materials.

Cr [%] Ni [%] Fe [%] Others

low low >90 C, Mn, Cu

> 20 >50 low Mo, Si, Mn, Co, Al, Ti

the results of the SEM-EDX analyses. The ferritic material formed a nice oxide scale of about 30 µm thickness at a temperature of 535 °C. The oxide layer was formed before the K and Cl hit the material surface. No indication of Clwas detected. Above the KCl border, loose particles build the deposit. The particles show a

an advantage for cleaning the super heater bundles.

pictures of the ferritic sample after 90 hours’ exposure at 535 °Cand lee side (right).

alloy shows a typical two-layer oxide scale with Ni-oxide below and Cr). Differently to the ferrite at lower temperature, the deposit shows a molten

K and Cl are spread homogeneously. This adverse deposition behavioproblematic for the cleaning system.

ement mappings of the Alloy 617 after 90 hours’ exposurewindward side.

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Others [%]

C, Mn, Cu

Mo, Si, Mn, Co, Al, Ti

he ferritic material formed a °C. The oxide layer was

formed before the K and Cl hit the material surface. No indication of Cl-induced corrosion was detected. Above the KCl border, loose particles build the deposit. The particles show a

an advantage for cleaning the super heater bundles.

at 535 °C , windward (left)

below and Cr-oxide eposit shows a molten

. This adverse deposition behaviour is

exposure at 660 °C,



Date: 15.03.2013

Both the Ni-based and the ferritic materials show Cl in the deposits at different despite of the very low Cl content in the fuel, but in different forms. Ongoing damaging of material or decrease of material thickness should be detected with longhundred hours in the wood fired boiler

Increasing the steam temperatures whilerequires to use new materials or base materials with a coating resistance against corrosion. have a constant firing system,oxide layer before (co-)firing could either catch alkalis to prevent KCl or NaCl from forming and sulphation of the alkalis. However, without sulphur (e.g. Al-Si rich mineralsotherwise likely to occur.

7.3 Lab-scale and pilot

ECN and USTUTT (IFK) performed labcarried out on a lab-scale droppercentages may create large the ash. It is therefore beneficial to focus on cocardoon combustion.

In a pulverised-fuel pilot-scale 0.5exchanger during pure cardoon (100% thermal share) combustion, for the high thermal share of 50% cardoon coand testing of the deposits from pure cardoon combustion showwhich was analysed and found to be rich with potassium compounds, i.e. alkali salts

This potentially problematic depositbe attributed to the high sulphur content of the lignitesulphation of alkalis despite the calcium content. content, sulphur lean fuel, there may be more risks regarding deposit phenomena in a boiler when firing high thermal shares of cardoon.

Hence, co-firing of herbaceous and agricultural biomass fuels may be challenging with certain coal types that are not a sulphur rich fueldetermine those biofuels that may or may not be considered for hiwith sulphur lean coals or for pure combustion.

7.4 Lab-scale c ombustion

WUT performed a co-firing test in a50% straw thermal share. Thethe higher emission of CO was due to the unstable conoticed. Thereby, 50% and higher cobiomass fuels would need further studies to the fuels to a proper particle size to ensure good combustion and burnout boilers may result being challenging.

7.5 Modelling activities

USTUTT (IFK) performed modelling activities. The capability of code AIOLOS was demonstrated to predict the combustion behaviour of cocoal with a herbaceous biomass. It was found that the calculated temperature and major species concentrations match most of thefacility. Furthermore, the results which are classified as



based and the ferritic materials show Cl in the deposits at different despite of the very low Cl content in the fuel, but in different forms. Ongoing damaging of material or decrease of material thickness should be detected with longerhundred hours in the wood fired boiler).

m temperatures while firing biomass or fuels with high biomass new materials or base materials with a coating properly designed for higher

resistance against corrosion. In order to protect the super-heater materialshave a constant firing system, to avoid stable temperatures and to get a primary protecting

biomass with high S and Cl contents. Additives (solid/liquid) catch alkalis to prevent KCl or NaCl from forming and depositing or support

However, at steam temperatures above 600 °C Si rich minerals) is preferred, since S-induced corrosion

scale and pilot -scale deposition tests

performed lab-scale and pilot-scale tests, respectively. cale drop-tube furnace simulator, it was concluded

percentages may create large amounts of fine ash due to an increased salt concentration in efore beneficial to focus on co-firing cardoon with coals, as opposed to pure

scale 0.5-MW facility, experiments led to pluggingexchanger during pure cardoon (100% thermal share) combustion, whilefor the high thermal share of 50% cardoon co-firing with Greek lignite. Also, visual inspection and testing of the deposits from pure cardoon combustion showed a very bright

ed and found to be rich with potassium compounds, i.e. alkali salts

potentially problematic deposit not being observed at 50% cardoon thermal share be attributed to the high sulphur content of the lignite, which still has the potential to create sulphation of alkalis despite the calcium content. Thus, with a parent fuel of a lower sulphur content, sulphur lean fuel, there may be more risks regarding deposit phenomena in a boiler

ares of cardoon.

of herbaceous and agricultural biomass fuels may be challenging with certain coal types that are not a sulphur rich fuel. Further studies would be needed

fuels that may or may not be considered for high co-firing thermal shares for pure combustion.

ombustion behaviour

test in an IFR (Isothermal Flow Reactor) fed with ahe CO concentration resulted to increase by 80 ppm. In that case

the higher emission of CO was due to the unstable co-firing, and a high LOI value50% and higher co-fired thermal shares of herbaceous and agricultural

biomass fuels would need further studies to assess the combustion behaviothe fuels to a proper particle size to ensure good combustion and burnout

challenging.

Modelling activities

performed modelling activities. The capability of the 3D combustion simulation code AIOLOS was demonstrated to predict the combustion behaviour of cocoal with a herbaceous biomass. It was found that the calculated temperature and major

ecies concentrations match most of the experimental data from the 0.5-facility. Furthermore, the results which are classified as the basic simulation were utilis

D7.10

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based and the ferritic materials show Cl in the deposits at different temperatures despite of the very low Cl content in the fuel, but in different forms. Ongoing damaging of

er term tests (some

biomass or fuels with high biomass content designed for higher

heater materials, it is important to temperatures and to get a primary protecting

high S and Cl contents. Additives (solid/liquid) depositing or support the

°C an alkali adsorber induced corrosion would be

scale tests, respectively. From tests it was concluded that high cardoon

increased salt concentration in firing cardoon with coals, as opposed to pure

d to plugging of a heat-while this did not occur

with Greek lignite. Also, visual inspection ed a very bright deposit,

ed and found to be rich with potassium compounds, i.e. alkali salts.

not being observed at 50% cardoon thermal share may , which still has the potential to create

hus, with a parent fuel of a lower sulphur content, sulphur lean fuel, there may be more risks regarding deposit phenomena in a boiler

of herbaceous and agricultural biomass fuels may be challenging with would be needed to firing thermal shares

) fed with a fuel mix at by 80 ppm. In that case

high LOI value was also fired thermal shares of herbaceous and agricultural

assess the combustion behaviour, since milling the fuels to a proper particle size to ensure good combustion and burnout in pulverised fuel

3D combustion simulation code AIOLOS was demonstrated to predict the combustion behaviour of co-firing a lignite coal with a herbaceous biomass. It was found that the calculated temperature and major

-MW pilot-scale test the basic simulation were utilised as



Date: 15.03.2013

boundary conditions to predict the fouling tendency in a post processthat the study carried out resulted in a highly practical model able to predict the combustion behaviour, the formation of econdensates in the first layer of a deposit due thigh potassium content) on a cooled supertool for the investigation of coMoreover, the use of soluble alkali species from chemical fractionation analyses of fuels in conjunction with the model will produce enhanced results

7.6 Lab-scale p yrolysis test

WUT carried out testing activities focused on the fuel devolatilisation and consisting in thepyrolysis of selected fuels in an was set at 3·10-4 Nm3/s and 6residue produced in the IFR during characterised in accordance with

Figure

The gas composition obtained through 22, indicating the concentration of CH1000 °C with 1- second residence time.at 600 °C and 800 °C with 1- second residence time and for thresidence time. The gas concentration



boundary conditions to predict the fouling tendency in a post processing step. It is believed that the study carried out resulted in a highly practical model able to predict the combustion behaviour, the formation of emissions, and the deposit build-up (mainly concerning the condensates in the first layer of a deposit due to a certain fuel quality, such as those with a high potassium content) on a cooled super-heater surface; thereby, this model provides a tool for the investigation of co-firing alternative fuels in a pulverised fuel combustion facility.

f soluble alkali species from chemical fractionation analyses of fuels in conjunction with the model will produce enhanced results.

yrolysis test s

carried out testing activities focused on the fuel devolatilisation and consisting in thepyrolysis of selected fuels in an IFR in nitrogen atmosphere. The global nitrogen flow rate

/s and 6·10-4 Nm3/s, while the fuel mass rate was 0.4 g/s. IFR during the pyrolysis as well as the parent ma

ed in accordance with the procedure schematically illustrated in

Figure 16: Scheme of the analytical procedure.

as composition obtained from the biomass pyrolysis tests is shown the concentration of CH4, CO, CO2 and H2 in the gas probe obtained at

second residence time. For rape waste, the data is also reported for the tests second residence time and for the test at 1000 °C with 2

concentration is referred to the gas mixture without nitrogen.

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ing step. It is believed that the study carried out resulted in a highly practical model able to predict the combustion

up (mainly concerning the o a certain fuel quality, such as those with a

, this model provides a ed fuel combustion facility.

f soluble alkali species from chemical fractionation analyses of fuels in

carried out testing activities focused on the fuel devolatilisation and consisting in the . The global nitrogen flow rate

rate was 0.4 g/s. The solid pyrolysis as well as the parent materials were

in Figure 16.

is shown in the Tables 19 in the gas probe obtained at

reported for the tests e test at 1000 °C with 2 -second

gas mixture without nitrogen.



Date: 15.03.2013

Table 19: Composition of pyrol

Biomass m

Wood pellet

Wood pellet

Wood pellet

Table 20 : Composition of

Biomass material

Sunflower

Wheat pasture

Wheat rye

Rape waste 1000

Rape waste 1000

Rape waste at 800

Rape waste at 600

Table 21

RDF material

RDF A

RDF B



Composition of pyrolytic gases from wood biomasses.

Biomass material % CH4 % CO % CO2 % H

Wood pellet A 11.71 50.58 6.32 31.39

Wood pellet B. 12.34 47.18 7.21 33.28

Wood pellet C 10.20 48.43 9.00 32.37

Composition of pyrolytic gases from agro-biomasses.

Biomass material % CH4 % CO % CO2 %

Sunflower 13.69 42.89 11.95 31

Wheat pasture 11.12 42.41 9.77 36

Wheat rye 11.98 48.99 8.93 30

Rape waste 1000 °C 14.79 38.47 10.01 36

Rape waste 1000 °C t res= 2 sec 12.09 40.50 10.93 36

Rape waste at 800 °C t res= 1 sec 31.11 40.91 12.63 15

Rape waste at 600 °C t res= 1 sec 43.45 39.65 14.17 2

21: Composition of pyrolytic gases from RDF.

RDF material % CH4 % CO % CO2 % H2

RDF A 16.1 36.9 10.9 36.1

RDF B 23.7 24.8 28.1 23.4

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tic gases from wood biomasses.

H2

39

28

37

biomasses.

% H2

31.47

36.70

30.10

36.73

36.49

15.36

2.74



Date: 15.03.2013

Table 22: Composition of

Fuel

Hard coal 1

10% Wood pellet B + 90% Hard coal 1

30% Wood pellet B + 70% Hard coal 1

10% Rape waste + 90% Hard coal 1

30% Rape waste + 70% Hard coal 1

Greek l

Hard c

10% Cardoon + 90% Greek

50% RDF + 50% Hard coal

The lowest H2 content was observedwaste devolatilisation at 600 °C and 800 °C. relevant char was the highest.

The highest values of the Hcoal/biomass blends, regardless amount in the blend, the higher the hydrogen content in the pyrolytic gas, with the exception of the 10% rape-waste/hard-coal

7.7 Lab-scale a dditive testing

The problem of the high fouling and slagging tendency limits the biomass share in the of halloysite (Al4(OH)8/Si4O10·the Kaolinites. It naturally occurs as characterised by a high surface area (~reactivity. Halloysite manly containsmagnesium, nickel and copper

The addition of halloysite is expected to ash and the test results confirmed this additive beingdeposit formation. Besides, furtherenhancement as well as lower



Composition of pyrolytic gases from fuel blends.

Fuel % CH4 % CO % CO2

Hard coal 1 16.98 18.10 5.21

10% Wood pellet B + 90% Hard coal 1 16.89 20.01 4.01

30% Wood pellet B + 70% Hard coal 1 12.14 32.92 5.22

10% Rape waste + 90% Hard coal 1 15.44 17.78 5.18

30% Rape waste + 70% Hard coal 1 15.19 24.87 5.77

lignite 4.76 53.60 4.23

Hard coal 2 15.53 22.11 6.16

10% Cardoon + 90% Greek lignite 3.30 57.31 2.50

+ 50% Hard coal 1 10.7 31.6 12.6

content was observed in the pyrolytic gas obtained from 600 °C and 800 °C. Consequently, the hydrogen content in th

.

H2 content were noticed in the gases from pyrolysis of hard, regardless of the H2 content in the raw blend. The higher the coal

amount in the blend, the higher the hydrogen content in the pyrolytic gas, with the exception coal blend showing a higher H2 content than coal.

dditive testing

high fouling and slagging tendency while co-firing agricultural biomass the fuel blend. WUT carried out testing activities

·10H2O). Halloysite is a mineral raw material from the gnaturally occurs as nanotubes and platelets loosely linked together and

characterised by a high surface area (~70÷85 m2/g) as well as high melting point and manly contains compounds of Si, Al and Ti. Impurities of chromium

nickel and copper are also very often present.

is expected to raise the sintering and softening temperature of the confirmed this additive being effective in reduci

Besides, further positive effects were observedlower NOx emissions.

D7.10

(79)

% H2

59.71

59.08

49.71

61.61

54.17

37.41

56.20

36.90

45.0

from the 1-second rape the hydrogen content in the

from pyrolysis of hard-The higher the coal

amount in the blend, the higher the hydrogen content in the pyrolytic gas, with the exception content than coal.

firing agricultural biomass carried out testing activities with the addition

mineral raw material from the group of atelets loosely linked together and is

h melting point and mpurities of chromium, iron,

oftening temperature of the effective in reducing slagging and

positive effects were observed, i.e. a burnout

DEBCO D7_10 - VGB PowerTech

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