Low grade thermal energy sources and uses from the process industry in the UK

Transcription

1 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 October 2011

2 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

3 Incentive to Save Energy Fuel price indices for the industrial sector Coal Electricity Gas Oil

4 A new Incentive to Save Energy Europe wide drive for CO 2 reduction has lead to legislation (UK Governmental target is a reduction of 80% by 2050 ) Climate Change Levy Emissions Trading Carbon Reduction Commitment IPPC CO2 emissions by energy use October 2011 SusTEM2011 Source: UK NAEI (2004)

5 Industrial heat use 22% of the total energy use in the UK Source: UK NAEI (2004)

6 Common heat recovery applications in the process industry Pre-heating feed water for a boiler pre-heating combustion gas for aluminium furnace Source : Econotherm

7 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

8 Energy management in the Process Industry 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

9 What do we mean by low grade heat? Products Process optimisation and heat integration Low grade heat sources available for over the fence recovery solution

10 Low grade heat (MW) Low grade heat sources from main process industrial sectors Estimation of the industrial low grade heat rejected to the environment in the UK (MW) Carbon trust (2010) Government s Office of Climate Change (2008) Sources Mc Kenna (2009) Estimation of the industrial low grade heat per sector(mw) Glass Steel Chemical Oil Process industrial sector (Source: Institution of Electrical Engineers, 1994)

11 Examples of low grade heat sources Low grade heat sources identified in a steelworks Low grade heat sources identified in a papermill with integrated CHP Water (35-50 C) 30% Steam (200 C) 40% gas ( C) 30% moist air ( C) 37% Steam (50 C) 3% water (35-50 C) 60% Low grade temperature between 30 C and 250 C

12 Challenges for low grade heat recovery Energy available for work production decreases with source temperature Maximum energy available for recovery Temperature ( C)

13 Applications for low grade heat Hydrogen production Desalination Ammonia production Greenhouses Low grade heat sources from Process Industry Heating building Biomass drying Biogasification Energy storage Power production Synergy

14 Recovering heat from flue gas Gas to gas heat exchanger Heat pipe schematic representation Source : Econotherm design

15 Recovering latent heat from flue gas Flue gas to water heat exchanger Indirect contact flue gas condenser Direct contact flue gas condenser Water return Flue gas inlet Packed bed HEX Shell and tube October 2011 SusTEM2011

16 Power production Rankine Cycle (RC) principle Heat Exchanger Pump Flue Gas Turbine Condenser Source: SINTEF energy research (2010)

17 Power processes and working fluids Low grade heat temperature 250 C RC Water/steam ORC Hydrocarbons HFC % Kalina Ammonia/water 90 C 70 C Transcritical cycle CO 2 R&D Efficiency

18 Reusing heat for domestic heating or cooling applications Flue gas Remaining heat Heat exchanger Rankine cycle Heat pump Working fluid Heating/Cooling domestic demand

19 Using low grade heat to produce fresh water

20 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.

21 Potential heat sinks: example of Port Talbot Heat consumers 25 km 9 km 1 km Public Buildings (MW) Commercial Offices (MW) Hotel and Catering (MW) Other Services (MW) Retail (MW) Sport and Leisure (MW) Small Scale Industrial (MW) Domestic (MW) Schools (MW) Hospitals (MW) Warehouses (MW) Total (MW)

22 Economic distance from the source to the end-user site 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? It depends on: -Type of transport media -Temperature of transport fluid -Pipe insulation efficiency and pipe material - cost invested in heat transportation 5 km 30 km 50 km 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)

23 Upgrading the economics of heat recovery project with heat storage Cylindrical capsules filled with phasechange material are integrated into a pressure vessel 400kWh thermal capacity solid-media storage unit 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

24 Maximising energy savings and mitigating environmental impacts thanks to a holistic approach Water filtering Cooling water HEAT BUS FOR T<T eco HEAT BUS FOR T>T eco LOW GRADE HEAT RECOVERY Wind farm Steel Chemical Pulp & Paper Food & Drink Transport Finished products Raw materials Fossil energy Solid/water waste Cement Electricity Recycling unit Non recyclable by-products

25 Example of a holistic approach: Cryogenic electricity storage system (copyright: Highview Power Storage)

26 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