210 likes | 508 Views
Vehicle Waste Heat Recovery Using Thermally Regenerative Fuel Cells. Andrew Carrier 1 , Dominik Wechsler 1 , Philip Jessop 1 , Boyd Davis 2 1 Department of Chemistry 2 Queen’s-RMC Fuel Cell Research Centre Queen’s University Kingston, Ontario, Canada. Hydrogen + Fuel Cells 2009
E N D
Vehicle Waste Heat Recovery Using Thermally Regenerative Fuel Cells Andrew Carrier1, Dominik Wechsler1, Philip Jessop1, Boyd Davis2 1Department of Chemistry 2Queen’s-RMC Fuel Cell Research Centre Queen’s University Kingston, Ontario, Canada Hydrogen + Fuel Cells 2009 Vancouver, BC, CANADA June 2, 2009
Problem • Transport trucks use ~ $5.3 billion worth of fuel a year in Canada. • About 70% of fuel energy is lost as waste heat from the exhaust and engine block. • Recovery of some waste heat would result in significant fuel savings. auxiliary electrical systems energy from fuel heating of engine heating of exhaust
Proposed Solution • Thermally regenerative fuel cell (TRFC). • Fuel cell could power a hybrid electric engine or auxiliary components. • Vehicle radiator would be replaced with dehydrogenation reactor. • Fuel cell would be used to charge a battery which could then be used for electric assist driving or in place of idling an engine. H2 electricity fuel cell reactor A A B + H2 B waste heat
Recovery Goal • For diesel trucks ~ 40% lost as waste heat • Goal is to capture 10% of this heat • (4% of fuel saved) • Value greater since it would replace APU electricity • Average transport truck mileage is about 100,000 km with annual fuel costs of $30K • 5% savings is $1500 per year • Payback 3 years on 20 year lifespan assuming 5K installation -CONFIDENTIAL-
Recovery Goal • Long haul trucking ideal for product entry • High fuel consumption • Low braking (no regenerative braking) • High APU demand • Underhood space • Fuel cell would act in a non-critical role • Emissions with start and stop trucking
Fluid Properties • React with excellent selectivity • Liquid • Boiling point > 200 ºC • High thermal stability • Rapid reaction rates • Low cost • Low toxicity
State of the Art • Isopropanol-acetone system • (CH3)2CHOH (CH3)2CO + H2 • Aqueous system • Uses low quality heat (100 °C) • V and I both improved with higher acetone/isopropanol ratio at cathode
Thermodynamics • Hydrogenation is favoured at low T • Dehydrogenation is favoured at high T • Reaction thermodynamics are understood • Predictable equilibrium compositions • Predictable cell voltages
Selectivity The current selectivity is >99.9% which is the limit of detection for our analytical method.
Kinetics • Initial rate is 3.6 L‐H2 min-1 kg-1. • Rate decreases as reaction approaches equilibrium. • Reaction will reach steady state with that of the fuel cell.
Fuel Cell • Hydrogenation proceeds in fuel cell. • Cell potential drops rapidly if flow of hydrogen acceptor across the cathode is stopped. • Cell potential is dependent on the difference of the fluid composition from its equilibrium composition. • Cell potential is highest when the difference between the two temperature regions is highest.
Benefits • Technology would help the local automotive industry have an advantage in the international marketplace. • Decreased fuel cost decreases the cost of shipping goods. • Decreased fuel use lowers greenhouse gas emissions
Current Status • A number of candidate systems have been identified as a result of a screening of potential compounds • Two systems have been tested in a fuel cell coupled to a regeneration reactor. • Both performed well • Voltages as expected • Steady output • Membrane stable
Future Work • Develop system where dehydrogenated material boils at a substantially lower temperature. • Dehydrogenated material is concentrated in the cathode stream. • High rates are maintained. • Cell potential is improved. • Pumping requirements reduced.
Future Work • Explore commercially available materials • Develop rapid catalyst screening methods • Produce new catalysts in-house • Run prototype fuel cells • Integrated operation • Connect to diesel engine • Rate of heat absorption • Economic evaluation following above work • Non-automotive applications