Review of Low Grade Thermal Energy Sources and Uses from ... · Low grade thermal energy sources...
Transcript of Review of Low Grade Thermal Energy Sources and Uses from ... · Low grade thermal energy sources...
Low grade thermal energy sources and uses from the process industry
in the UK
Yasmine Ammar, Sharon Joyce, Rose Norman, Yaodong Wang, Anthony P. Roskilly
Sustainable Thermal Energy Management in the Process Industries International Conference (SusTEM2011)
Newcastle upon Tyne, UK 25-26 October 2011
25 - 26 October 2011 Newcastle Upon Tyne SusTEM2011
Outline • Past and current drivers to recover heat.
• Low grade heat definition
• Low grade heat sources in the UK and potential market for this energy
• Thermodynamic constraints on low grade heat recovery and potential end-users
• Factors influencing the decision process for stakeholders of low grade heat recovery projects
25 - 26 October 2011 Newcastle Upon Tyne SusTEM2011
Incentive to Save Energy
Fuel price indices for the industrial sector
Coal
Gas
Electricity Oil
1973
1986
2005
75
245
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Europe wide drive for CO2 reduction has lead to legislation (UK Governmental target is a reduction of 80% by 2050 )
• Climate Change Levy • Emissions Trading • Carbon Reduction Commitment • IPPC
A new Incentive to Save Energy
Source: UK NAEI (2004)
CO2 emissions by energy use
Newcastle Upon Tyne SusTEM2011 25 - 26 October 2011
Industrial heat use
22% of the total energy use in the UK
Source: UK NAEI (2004)
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Common heat recovery applications in the process industry
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Source : Econotherm
Pre-heating feed water for a boiler pre-heating combustion gas for aluminium furnace
Research area
• Heat exchanger selection for heat recovery
• Intensified heat and mass transfer (compactness/ performance)
• Fouling and ageing of heat exchangers
• Heat exchanger network and retrofits
• Process intensification (pinch analysis, total site analysis)
• Improved combustion for fired heaters, boilers, furnaces
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Energy management in the Process Industry
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Experienced Engineer
has rules of the thumb
State of the art, Best practice, energy monitoring
(energy use/ tonne of products)
Optimisation/intensification tool, Modelling, CFD simulation, entropy generation minimisation
algorithm
What do we mean by low grade heat?
Products
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Low grade heat sources available for
over the fence recovery solution
Process
optimisation and
heat integration
Low grade heat sources from main
process industrial sectors
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Glass Steel Chemical Oil
Process industrial sector
0
2000
4000
6000
8000
10000
12000
Carbon trust (2010)
Government’s Office of Climate Change (2008)
Mc Kenna (2009)
Low
gra
de
he
at (
MW
)
Sources
Estimation of the industrial low grade heat rejected to the environment in the
UK (MW)
(Source: Institution of Electrical Engineers, 1994)
Estimation of the industrial low grade heat per sector(MW)
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Examples of low grade heat sources
gas (30-220°C)
30%
Steam (200°C)
40%
Water (35-50°C)
30%
Low grade heat sources identified in a steelworks
Steam (50°C)
3%
water (35-50°C)
60%
moist air (50-109°C)
37%
Low grade heat sources identified in a papermill with integrated CHP
Low grade temperature between 30 °C and 250 °C
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30 50 150 250
Temperature (°C)
Maximum energy available for recovery
Challenges for low grade heat recovery
• Energy available for work production decreases with source temperature
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Applications for low grade heat
Biomass drying
Heating building
Greenhouses
Biogasification
Desalination
Hydrogen production
Ammonia production
Synergy Energy storage Power
production
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Low grade heat sources from Process
Industry
Recovering heat from flue gas
• Gas to gas heat exchanger
Heat pipe schematic representation Source : Econotherm design
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Recovering latent heat from flue gas
• Flue gas to water heat exchanger
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Newcastle Upon Tyne
Indirect contact flue gas condenser Direct contact flue gas condenser
Flue gas inlet
Water return
Shell and tube
Packed bed
HEX
Power production
• Rankine Cycle (RC) principle
Source: SINTEF energy research (2010)
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Heat Exchanger
Flue Gas
Turbine
Pump
Condenser
Power processes and working fluids
250°C
90°C
70°C
RC •Water/steam
ORC •Hydrocarbons •HFC
Kalina •Ammonia/water
Transcritical cycle •CO2
R&D
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+20-50%
Efficiency
Low grade heat temperature
Reusing heat for domestic heating or cooling applications
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Heat exchanger Rankine cycle Heat pump
Heating/Cooling domestic demand
Flue gas
Working fluid
Remaining heat
Criteria for low grade heat recovery (Reay,1980)
• Low grade heat is available at a useful temperature at the sink
• Low grade heat can be economically transferred from the source to an identified end-user sink
• Coincidence of heat supply and demand occurs.
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Potential heat sinks: example of Port Talbot
Heat consumers 25 km 9 km 1 km Public Buildings (MW) 2.141 0 0
Commercial Offices (MW) 0.757 2 0
Hotel and Catering (MW) 2.642 0 0
Other Services (MW) 1.025 8 0
Retail (MW) 2.518 5 0
Sport and Leisure (MW) 0.613 0 0
Small Scale Industrial (MW) 41.991 0 0
Domestic (MW) 100.72 3 0.2
Schools (MW) 0.866 0 0
Hospitals (MW) 0.675 0 0
Warehouses (MW) 1.775 0 0
Total (MW) 155.7 18 0.2
Economic distance from the source to the end-user site
50 km 30 km 5 km
Steam at 250 °C:
Water at 150°C
Water-Ammonia pair
(Generation temperature~100°C)
Which transportation radius to look at low grade heat end-users?
Long distance transportation system- Lin et al (2010) 500 MW transported over 50 km with a payback period < 3
years (China nuclear waste heat transportation)
It depends on: -Type of transport media -Temperature of transport fluid -Pipe insulation efficiency and pipe material - cost invested in heat transportation
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Upgrading the economics of heat recovery project with heat storage
400kWh thermal capacity solid-media storage unit
Cylindrical capsules filled with phase-change material are integrated into a pressure vessel
heat exchanger for the latent-heat storage unit, with fins made of graphite foil, before integration of phase-change material between fins.
Source: Institute of Technical Thermodynamics, German Aerospace Center (DLR), Stuttgart, Germany
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Maximising energy savings and mitigating environmental impacts thanks to a holistic approach
Solid/water waste
HEAT BUS FOR T<Teco
HEAT BUS FOR T>Teco
Steel
Pulp & Paper
Chemical
Cement
Food & Drink
Cooling water
Transport
Finished products
Wind farm
Water filtering
Raw materials
Non recyclable by-products
Recycling unit
LOW GRADE HEAT RECOVERY
Fossil energy
Electricity
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Example of a holistic approach: Cryogenic electricity storage system
(copyright: Highview Power Storage)
Barriers/obstacles • Economic: high payback period • Difficulty of data collection from heat suppliers and
technology manufacturers • Risk for the heat supply provider/ end-user with
reliability of the source as main obstacle • Corrosive nature of the heat as low temperature
implies an extra cost • Organisational structures: energy project considered of
second importance and consequently poorly monitored
• Need of governmental policy and regulation incentives
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