T. Grube

Fuel cell drive system with hydrogen generation in test

In the future, drive systems for vehicles with polymer electrolyte membrane fuel cells (PEMFC) may be the environmentally more acceptable alternative to conventional drives with internal combustion engines. The energy carrier may not be gasoline or diesel, as in combustion engines today, but methanol, which is converted on-board into a hydrogen-rich synthesis gas in a reforming reaction with water. After removal of carbon monoxide in a gas-cleaning step, the conditioned synthesis gas is converted into electricity in a fuel cell using air as the oxidant. The electric energy thus generated serves to supply a vehicles electric drive system. n nBased on the process design for a test drive system, a test facility was prepared and assembled at Forschungszentrum Julich (FZJ). Final function tests with the PEMFC and the integrated compact methanol reformer (CMR) were carried out to determine the performance and the dynamic behaviour. With regard to the 50-kW(H2)-compact methanol reformer, a special design of catalytic burner was constructed. The burner units, with a total power output of 16 kW, were built and tested under different states of constant and alternating load. If selecting a specific catalyst loading of 40 g Pt/m2, the burner emissions are below the super ultra low emission vehicle (SULEV) standard. The stationary performance test of the CMR shows a specific hydrogen production of 6.7 mN3/(kgcat h) for a methanol conversion rate of 95% at 280°C. Measurements of the transient behaviour of the CMR clearly show a response time of about 20 s, reaching 99% of the hydrogen flow demand due to the limited performance of the test facility control system. Simulations have been carried out in order to develop a control strategy for hydrogen production by the CMR during the New European Driving Cycle (NEDC). Based on the NEDC, an optimized energy management for the total drive system was evaluated and the characteristic data for different peak load storage systems are described.

Operational experience with the fuel processing system for fuel cell drives

Abstract Electric motor vehicle drive systems with polymer electrolyte fuel cells (PEFCs) for the conversion of chemical into electrical energy offer great advantages over internal combustion engines with respect to the emission of hydrocarbons, carbon monoxide and nitrogen oxides. Since the storage systems available for hydrogen, the “fuel” of the fuel cell, are insufficient, it is meaningful to produce the hydrogen on board the vehicle from a liquid energy carrier, such as methanol. At the Research Center Julich such a drive system has been developed, which produces a hydrogen-rich gas from methanol and water, cleans this gas and converts it into electricity in a PEFC. This system and the operational experience on the basis of simulated and experimental results are presented here.