Susumu Nagano

Heat transfer enhancement in methanol steam reforming for a fuel cell

Abstract The catalytic methanol steam reforming reaction was investigated by numerical simulation and experiments. Methanol conversion ratio as well as carbon monoxide (CO), which poisons a typical polymer electrolyte fuel cell, increases in a tablet catalyst when temperature is elevated. There is a trade-off relationship between methanol conversion ratio and CO concentration. It was found that the reforming reaction is controlled by heat transfer at large methanol flow rate, where the trade-off relationship shifts to lower methanol 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 transfer. Optimal cell density for the internal corrugated metal heater, which was about 9×10 5 cell/m 2 , was closely related with reaction parameters such as velocity, cell density, geometric surface area and hydraulic diameter. The catalytic combustion heater is larger than the internal corrugated metal heater in size. Both high methanol conversion ratio and low CO concentration were accomplished by heat transfer enhancement with the two techniques at large methanol flow rate.

Reduction of exhaust emissions by air-jet turbulence in a DI diesel engine: application to an in-line 6-cylinder engine

In our previous study, it has been reported that exhaust smoke can be reduced in an experimental single cylinder diesel engine with the use of air-jet turbulence in the late combustion period. In this study, a device to generate air-jet turbulence in the late combustion period was applied to 6-cylinder DI diesel engine. The effect of parameters such as air-jet direction and timing were investigated. Smoke and particulates were reduced significantly without increasing NOx. Total particulates reduction by the air-jet in Japanese D13 mode is 37% for the constant NOx.