Heat transfer enhancement in methanol steam reforming for a fuel cell

The catalytic methanol steam reforming reaction was investigated by numeric al simulation and experiments. Methanol conversion ratio as well as carbon monoxide (CO), which poisons a typical polymer electrolyte fuel cell, incre ases in a tablet catalyst when temperature is elevated. There is a trade-of f relationship between methanol conversion ratio and CO concentration. It w as found that the reforming reaction is controlled by heat transfer at larg e methanol flow rate, where the trade-off relationship shifts to lower meth anol conversion ratio and higher CO concentration. To improve the trade-off relationship, internal corrugated metal heater and external catalytic combustion heater were applied to enhance the heat tran sfer. Optimal cell density for the internal corrugated metal heater, which was about 9 x 10(5) cell/m(2), was closely related with reaction parameters such as velocity, cell density, geometric surface area and hydraulic diame ter. The catalytic combustion heater is larger than the internal corrugated metal heater in size. Both high methanol conversion ratio and low CO conce ntration were accomplished by heat transfer enhancement with the two techni ques at large methanol flow rate. (C) 2001 Elsevier Science Ltd. All rights reserved.