Partial oxidation reforming of methanol

Methanol is an attractive fuel for fuel cell-powered vehicles because it has a fairly high energy density, can be pumped into the tank of a vehicle mush like gasoline, and is relatively easy to reform. For on-board reforming, the reformer must be compact and lightweight, and have rapid start-up and good dynamic response. Steam reforming reactors with the tube-and-shell geometry that was used on the prototype fuel cell-powered buses are heat transfer limited. To reach their normal operating temperature, these types of reactors need 45 minutes from ambient temperature start-up. The dynamic response is poor due to temperature control problems. To overcome the limitations of steam reforming, ANL explored the partial oxidation concept used in the petroleum industry to process crude oils. In contrast to the endothermic steam reforming reaction, partial oxidations is exothermic. Fuel and air are passed together over a catalyst or reacted thermally, yielding a hydrogen-rich gas. Since the operating temperature of such a reactor can be controlled by the oxygen-to- methanol ratio, the rates of reaction are not heat transfer limited. Start-up and transient response should be rapid, and the mass and volume are expected to be small by comparison