ON-BOARD HYDROGEN GENERATION FOR TRANSPORT APPLICATIONS - THE HOTSPOT(TM) METHANOL PROCESSOR

In the absence of a hydrogen infrastructure, development of effective on-board fuel processors is likely to be critical to the commercialisa tion of fuel-cell cars. The HotSpot (TM) reactor converts methanol, wa ter and air in a single compact catalyst bed into a reformate containi ng mainly CO2 and hydrogen (and unreacted nitrogen). The process occur s by a combination of exothermic partial oxidation and endothermic ste am reforming of methanol, to produce 750 l of hydrogen per hour from a 245-cm(3) reactor. The relative contribution of each reaction can be tuned to match the system requirements at a given time. Scale-up is ac hieved by the parallel combination of the required number of individua l HotSpot reactors, which are fed from a central manifold. Using this modular design, the start-up and transient characteristics of a large fuel-processor are identical to that of a single reactor. When vaporis ed liquid feed and air are introduced into cold reactors, 100% output is achieved in 50 s; subsequent changes in throughput result in instan taneous changes in output. Surplus energy within the fuel-cell powertr ain can be directed to the manifold, where it can be used to vaporise the liquid feeds and so promote steam reforming, resulting in high sys tem efficiency. The small amount of CO that is produced by the HotSpot reactions is attenuated to < 10 ppm by a catalytic clean-up unit. The HotSpot concept and CO clean-up strategy are not limited to the proce ssing of methanol, but are being applied to other organic fuels. (C) 1 998 Elsevier Science S.A.