Boiler using Biomass as Fuel
Director of Renewable Energy and New Energy Technologies ProgramNational Science and Technology Development Agency (NSTDA)
Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass 16 June 2018, BITEC, Bangkok, Thailand
International Conference “The Future of ASEAN’S Energy Journey E‐mobility – Smart Grid – Smart City”6 June 2018, BITEC, Bangkok, Thailand
Suthum PATUMSAWADDepartment of Mechanical EngineeringFaculty of EngineeringKing Mongkut’s University of Technology North Bangkok (KMUTNB)
26 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Outlines of Presentation
General Description of Boilers Biomass Fuel Opportunity Technical Barriers Choosing the right Fuel? The need of Biomass Characterisation Concluding Remarks
General Description of Boilers
6 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass 3
A boiler (or steam generator) consists of a fossil fuels or biomass burner and a heat-transfer system to boil water and generate steam. Steam generators also include systems and components for pressure control, heat recovery, steam delivery and distribution, condensate drainage, and separation of oxygen and non-condensable gases.
46 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Use of Boilers
o Electrical generationo Chemical industryo Petroleum industryo Pulp & paper industryo Food industryo Etc.
56 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Fuel Opportunity
o Addresses key energy, economic, environmental and social problems at the local and global scale
Biomass fuel is :• Regenerative EnergyPlants continue to grow as long as existence of sun light, water and soil. Efficient use of biomass energy is applauded as fossil fuels become depleted.Agro-forestry wastes previously disposed of are recovered as fuel energy. This forms a recycling type community with reduced waste generation and efficient energy use• Earth-friendly EnergyPlants absorb CO2 in the growing process. Rich, green forests thus help prevent global warming.
66 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Fuel Opportunity
Power generation from biomass can be achieved with a wide range of feedstock which have different properties.
76 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Characteristics
• Lower density
• Higher moisture content, often up to 50%
• Lower calorific value
• Broader size distribution, unless pre-conditioned by screening, crushing or pelletising
• The variability of the material as a fuel will be greater
86 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass differs from conventional fossil fuels
• Physical structure
• Chemical structure
• Moisture content
Therefore it must be burnt differently.
Technical barriers
Effect of Moisture• Decreases combustion temperature• Leads to incomplete combustion
higher CO and Carbon in Ash• Decreases boiler efficiency• Leads to more fuel use, higher
energy costs and increased air pollutants
96 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Fuel - Volatiles
• 70 – 80% of dry biomass is “volatile” hydrocarbons.
• Released from the biomass structure at relatively low temperatures.
• Volatiles burn in “suspension” way from the biomass particles.
• Balance is “fixed carbon” or “char”.
106 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Fuel - Ash
116 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Fuel - Ash
• Combines with alumina and silica lowers melting point
• Slagging on grate and boiler tubes
• Ash accumulation Airflow problems High draft losses Reduced heat transfer Boiler shutdowns
126 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Biomass Fuel - Ash
• Agglomeration and Sintering problems
• Fouling and Slagging problems
• Corrosion and Erosion problems
136 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Choosing the right fuel?
Prior to design combustion system, answers to the following questions must be known:
Is the biomass which will be used apt for combustion system? What are the optimal conditions for the combustion of the specific biomass? What is the range of biomass which may be used in the specific combustion system?
146 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
The need ofBiomass Characterisation
Quality of biomass fuel is the most important point for the reliability of the plantAvoid ContaminantsControl moisture contentChemical analysis is critical to understanding of performance
The lack of sufficient information concerning biomass feeding as well as the combustion and emission characteristics of biomass.
This information is important for the design and efficient operation of combustion systems
156 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
The need of Biomass Characterisation
Useful important for the design and efficient operation of combustion systems
Biomass characterization• Identifies the fuel value• Provides an estimate of ash handling requirement• Describes something of the burning characteristics• Indicative of problems arising during combustion
166 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Some outputs: Fuel property analyses
Fuel sample Source
1. Lignite Coal (Lig) Thai lignite company, Lampang
2. Sub-bituminous Coal (SB) Asia Green company
3. Rice husk (RH) Rice field in Nakornphatom
4. Rice straw (RS) Rice field in Nakornphatom
5. Giant Leuceana Wood
(LW)Mitr Phol Group, Suphanburi
6. Eucalyptus Wood (EW) Asia charcoal company
7. Napier Grass (NP) Farm in Kanchanaburi
8. Palm empty fruit bunch
(EFB)
Suksomboon oil plam company,
Chonburi
9. Sugarcane Top and Leaf
(CT/L)Mitr Phol Group, Suphanburi
10. Sugarcane Leave (CL) Mitr Phol Group, Suphanburi
11. Wastewater sludge (Slud) Samutsakorn Industrial estate
Table 1. Fuel sample used in this study Fuel Properties Testing method
1. Proximate analysis
- Volatile matter
- Fixed carbon
- Ash (at 900OC)
ASTM D 5142 by TGA
2. Ultimate analysis
C, H, N, S, O
Organic elemental analyzer
(OEA)
3. Moisture content (%ar) ASTM D3173
4. Gross Heating Value Bomb Calorimeter
5. Ash content ASTM E1755 at 575OC
6. Chemical structure
- Hemicellulose
- Cellulose
- Lignin
TAPPI T203om-88
TAPPI T204 om-88
TAPPI T222 om-88
TAPPI T223 cm-01
(biomass only)
7. Ash composition XRF, XRD
8. Ash Fusion Temperature
(AFT) for coal only
Oxidation by air, Reduction
by CO/CO2 60/40 (v/v)
Table 2. Fuel properties and testing method11 fuel samples: 2 coals, 8 biomasses and 1 wastewater sludge
176 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Some outputs: Fuel property analyses
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Proximate analysis (dry basis, wt%)
Fixed carbon VM ash
Fuel Moisture
(wt%, ar)
HHV
(MJ/kg dry)
1. Lig 11.9 17.22
2. SB 9.4 20.85
3. RH 9.7 14.30
4. RS 10.1 15.37
5. LW 17.1 12.75
6. EW 13.4 16.57
7. NP 9.5 15.62
8. EFB 9.5 17.28
9. CT/L 8.6 16.11
10. CL 9.9 16.53
11. Slud 11.0 9.73
Table 3. Moisture content and HHV
Figure 1. Proximate analysis of the fuel samples
186 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Sample SiO2 Al2O3 SO3 CaO Fe2O3 MgO K2O Na2O MnO P2O5 Cl BaO TiO2 SrO Rb2O ZnO CuO Cr2O3 SnO2Sludge 9.02 19.86 12.44 34.91 5.93 1.44 0.68 1.37 0.11 7.07 0.29 0.22 3.08 2.99 0.46 0.12
Lignite 25.95 17.73 19.64 17.23 12.42 2.84 1.70 0.76 0.00 0.11 0.00 0.76 0.62 0.24
SB 23.78 17.16 13.04 12.54 25.59 4.28 1.23 0.59 0.48 0.18 0.00 0.00 0.96 0.15
NP 48.63 0.36 2.45 3.07 0 11.15 20.86 0.46 0 6.20 6.82
LW 6.52 1.76 4.95 40.69 3.86 7.09 28.76 1.32 0.45 3.09 0.52
CT/L 30.67 0.27 10.93 15.94 0.48 5.08 27.97 0.24 0.63 5.9 2.59 0.11
EW 1.43 0.92 8.30 5.99 0.80 10.37 34.85 1.65 1.49 14.20 0
EFB 11.65 0.31 2.65 12.46 4.72 3.42 56.45 0.29 0.27 4.13 3.47 0.18
RS 73.85 0.76 2.36 3.62 0 4.36 9.62 1.19 0.28 2.04 1.91
RH 93.83 0.07 0.39 0.91 0.78 0.35 2.74 0.04 0.18 0.52 0 0.07
Table 4. Ash composition of fuel sample by XRF (%wt dry ash)
- The major elements in both coals were Si, Al, Ca, Fe and also high in SO3
- NP, CT/L, RS, and EFB were high in both K and Cl and therefore likely to have ash
related problems
- Slud was high in Al, Ca and also high in Si and SO3
Some outputs: Fuel property analyses
196 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
BiomassChemical Structure (%wt, dry biomass)
Cellulose a Lignin b Hemicellulose c Extractives d
Rice husk (RH) 40.17 29.03 29.40 2.03
Rice straw (RS) 37.425 27.27 27.64 5.47
Leuceana Wood (LW) 31.58 31.60 23.37 1.89
Eucalyptus Wood (EW) 37.448 28.64 30.19 1.14
Napier Grass (NP) 36.438 24.70 30.82 5.28
Empty fruit bunch (EFB) 27.63 29.34 21.80 21.23
Cane Top and Leave (CT/L) 34.69 22.97 29.58 12.76
a TAPPI T203 om-88 (1992). “Alpha, beta, gramma cellulose in pulp” , b TAPPI T222 om-88 (1988). “Acid-insoluble lignin in wood and pulp”c TAPPI T223 cm-01 (2001). “Pentosans in wood and pulp” , d TAPPI T204 om-88 (1997). “Solvent extractives of wood and pulp”
Table 5. Chemical structure of biomass samples
Some outputs: Fuel property analyses
206 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Coal Atmosphere
Temperature (OC)
Initial
Deformation
Spherical
Temperature
Hemispherical
Temperature
Flow
Temperature
Lignite Reduction
(CO/CO2, 60/40 %v/v)
1,190 1,210 1,230 1,230
Oxidation (Air) 1,250 1,260 1,280 1,290
SB coal Reduction
(CO/CO2, 60/40 %v/v)
1,130 1,160 1,190 1,220
Oxidation (Air) 1,190 1,220 1,230 1,250
• Coals had relatively low IDT, especially under reducing atmosphere
Some outputs: Fuel property analyses
216 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Combustion characteristic of Single Fuels (example curves)
• Coal exhibited a one-step combustion, two-step
combustion (devolatilization followed by char
combustion) was clearly observed for biomass (incl.
sludge).
• Decomposition of biomass started at lower temperature
than coal was due to the higher VM content.
Figure 2. TG and DTG curve of single fuel combustion
Some outputs: Combustion characteristic of fuel
226 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Combustion characteristic of blend Fuels
Example 1: Lig/RS blends
Pure RS
Pure Lig
Pure RS
Pure Lig
Figure 3. TG curves of combustion of Lig/RS blends
Figure 4. DTG curves of combustion of Lig/RS blends
• Combustion behavior of the blends clearly presents the behaviour of individual
components that is the prior decomposition of biomass followed by that of coal.
Some outputs: Combustion characteristic of fuel
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Some outputs: Fouling tendency of fuel combustion
246 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Morphology of deposit (1000X)
Pure RS SB/RS (1:1)
Pure NP SB/NP (1:1)
Pure EFB
SB/EFB (1:1)
Pure CTLSB/CTL (1:1)
• Morphology of deposit
from co-combustion was
drastically changed into
the melted surfaces, in
particular SB/RS and
SB/NP
Pure SB
Deposit Bottom ash
Some outputs: Fouling tendency of fuel combustion
256 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
Some outputs: Simulation of fuel combustion
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Concluding Remarks
Although combustion technologies can already be considered as proven, there is a continuous demand for equipment with: Lower investment and operational cost Increased fuel flexibility Lower emissions Increased reliability and efficiency
Thank You
National Science and Technology Development Agency (NSTDA)
111Thailand Science Park Phahonyothin RoadKlong Nueng, Klong LuangPathum Thani 12120Thailand
Email: [email protected]
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286 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
296 June 2018, BITEC, Bangkok, Thailand Bio‐Energy: Pretreatment, Combustion and Pyrolysis of Biomass
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