Organic Rankine Cycles for Waste Heat Recovery

Transcription

1 Organic Rankine Cycles for Waste Heat Recovery NASA/C3P INTERNATIONAL WORKSHOP ON ENVIRONMENT AND ALTERNATIVE ENERGY Global Collaboration in Environmental and Alternative Energy Strategies 11. November 2009 Dr. Thomas Frey GE Global Research Center Munich (GRC)

2 Waste Heat Recovery Overview

3 What is Waste Heat Recovery (WHR)? Benefits CO 2 -free additional power Increased plant / process efficiency Fuel savings Driving forces Fuel, electricity prices / incentives CO 2 or emissions constraints Grid independence Key CTQ: CAPEX ($/kw) WHR System Heat Source Q in Q out Heat Sink Power Capturing low grade heat sources for energy production 3 /

4 Waste Heat Recovery Segments New Technology... Heat Recovery Program Focus Conventional GE Technology Geothermal Industrial Solar Engines & Gas Turbines Large GT 100 C 200 C 300 C 400 C 500 C 600 C Advanced Heat Recovery Technologies Conventional Steam Cycles Geothermal & Solar 100 GW geothermal potential (MIT) * 200 GW solar potential * Reciprocating Engines Approx. 5% pts efficiency boost Reduced fuel consumption & emissions Industrial Waste Heat Approx. 950 PJ heat losses ( C) * $6 B/yr energy wastes * Refineries, cement, pulp & paper, Gas Turbines WHR adds up to 20% power Green, CO 2 free technology (* US only) 4 /

5 Waste Heat Recovery Organic Rankine Cycle (ORC)

6 Organic Rankine Cycle Heat Source Cycle Principle BOILER Expansion of organic fluid Features Robust, simple system Pressurised liquid ORC Nearsaturated vapour Shaft Mature, well known components Fan Power Work Only low temperatures required On-site operators not required Pump Power CONDENSER Technology Status Conventional ORCs successfully in operation for many years CAPEX: ~ $/kw, f (kw, temp, site etc.) Advantaged technology for small and low T applications 6 /

7 ORC Efficiency Carnot efficiency Theoretical maximum Increases with increasing T Real efficiency Process always has losses 30 50% of Carnot Potential improvements Reduce losses Increase max. temperature (risk: fluid decomposition) Optimize cold cycle end (increased cost) Carnot efficiency / % Carnot efficiency: T ηc =1 T Tc=20 C Tc=40 C Temperature of heat source T h / C h c 7 /

8 Waste Heat Recovery Example: ORC for Reciprocating Engines

9 Gas Engine Heat Sources Fuel 3,4 MW Mechanical power Exhaust Gas 540 kw 1415 kw electrical power Challenges for waste heat recovery Use which sources? High specific cost due to low power Thermal integration into engine J 420 GS-A25 Biogas Intercooler Cooler Water Jacket Water Oil Oil C C ~810 kw ~95 C LT heat C (180) C ~600 kw ~472 C HT heat Two heat sources with different temperature level 9 /

10 Example: GE Jenbacher Recips WHR Reciprocating engine Containerised ORC Medium Large Specifications Engine power Fuel ORC power boost Efficiency increase 1 1,5 MW Biogas, landfill, NG kw > 4% pts 3 MW Natural Gas kw > 5% pts ORC: Bottoming cycle for reciprocating engines 10 /

11 GRC Waste Heat Recovery Focus Reciprocating Engines Industrial Gas Turbines Customer prototype installation Q1/2010 Approx. 5% pts efficiency boost Potential for 50%+ efficient engine GE O&G ORegen TM cycle developed ORC adds approx. 20% power to GT Ecomagination certified Real Fluid Cycle T Industrial Waste Heat Vapor dome Ideal (trilateral) Real Discovery s Collaboration with industry (e.g. utilities, cement, refineries etc.) Identification of new WHR opportunities & markets Development of high efficient cycles New fluids identification CAPEX optimized components Simulation & experiments Key to low $/kw: New cycles & integration into heat source 11 /

12 Thank you. Acknowledgement: Project is partly funded by the Bavarian Ministry for Economy, Infrastructure, Traffic and Technology 12 /