Reforming of Methane Using Single-mode Microwave Irradiation Heating in a Cylindrical Cavity

For the application of microwave heating to a continuous gas-flow type reaction using a solid catalyst, a cylindrical cavity system was used for reforming reaction of methane. A single standing microwave was generated within the cavity, resulting in uniform heating of the reaction tube positioned in the center of the cavity. Heating tests were conducted with different loadings of Pd/Al2O3 catalyst. Following hydrogen reduction, 5-10 wt% catalyst loading achieved the best heating effect and avoided reflection of microwaves. Reforming reactions were then conducted over 5 wt% Pd/Al2O3 catalyst using microwave heating and conventional heating, respectively. The conversion efficiency of methane for both steam reforming and dry reforming was higher by microwave heating than by conventional heating. In addition, microwave heating of the Ni/γ-Al2O3 catalyst restricted coke deposition attributed to direct dielectric heating by the microwave irradiation promoting carbon combustion. The results demonstrate the advantages of this microwave heating system for flow-type reactions using a solid catalyst.