Development of a Liquid Fueled PEMFC Power Plant for a Hybrid Transit Bus 972651

Under a grant from the Federal Transit Authority (FTA), Georgetown University has contracted with Ballard Power Corporation to develop a 100 kW (net) Proton Exchange Membrane Fuel Cell (PEMFC) power plant. The program's objective is to design and to build a liquid fueled PEMFC power plant for a 12.2 m (40 foot), hybrid transit bus. The Fuel Cell Power System (FCPS) is defined as a complete fuel cell system including controls, fuel reforming, air delivery, cooling sub-system, thermal integration, water recovery, and water treatment sub-system. Georgetown University has also contracted Booz-Allen and Hamilton as the system integrator who is teamed with Nova Bus and Kaman to provide the coach, traction motor with power electronics and vehicle system controller. A fully integrated hybrid transit bus is scheduled for delivery in the fourth quarter of 1998.

Liquid methanol is easily reformed to a hydrogen rich gas stream and has favorable weight and volume energy densities, therefore it is currently the most appropriate liquid fuel for fuel cell transportation applications. Neat methanol is used as the baseline in this program. The FCPS utilizes low temperature steam reforming to produce a hydrogen rich gas stream. Carbon monoxide (CO), a by-product of methanol steam reformation, is a poison to PEM fuel cells. Therefore, two independent, post-reformer “clean-up” technologies are under development to ensure CO concentrations are reduced to an acceptable threshold. The two technologies are palladium-based separation membranes and selective catalytic oxidation (SelOx). This paper seeks to explain the technical differences between these two power plant systems and to detail the overall development schedule of a 100 kW (net) PEMFC hybrid bus engine.