REACTION PERFORMANCE OF METHANOL REFORMING WITH STEAM OVER VARIOUS IMPREGNATED AND COPRECIPITATED COPPER-CATALYSTS

To establish a catalytic process for the steam-reforming of methanol, various impregnated-supported and coprecipitated catalysts (supports: Al2O3 (tau, theta, alpha), CaO, CeO2, Cr2O3, La2O3, MgO, Nb2O5, SiO2, TiO2, Y2O3, ZnO, ZrO2) were prepared and the relationship between reaction conditions and catalytic reaction performance was investigated, together with an examination of the effect of impurities (ethanol, acetone, acetic acid) in methanol on the catalytic activity. Furthermore, the catalytic decomposition of methanol and the reaction of carbon dioxide and hydrogen formed (the reverse reaction of shift conversion) were studied. The experiments were carried out using a fixed-bed flow reactor under atmospheric pressure at 200-degrees and 250-degrees-C. The inlet gases were mainly 10%CH3OH-10%H2O-N2, the total flow rate was 119 cm3N.min-1 per 1.0 ml of each catalyst with an average diameter of 1.0 mm, and the space velocity was 7.1 x 10(3) h-1. The main results obtained were as follows. (1) ZrO2 and alpha-Al2O3 were superior supports, giving good catalytic activity and selectivity, and the copper content was suitable at ca. 15 wt% for the impregnated-supported catalysts and ca. 70wt% for the coprecipitated catalysts. (2) The impurities in methanol caused a remarkable deactivation of catalysts above 10 ppm content, but were temporary poisons by the impurities, and in pure methanol the activities were completely recovered. (3) In ZrO2 and alpha-Al2O3 impregnated-supported copper catalysts, a by-product, carbon monoxide, was remarkably inhibited, and it was proved that this carbon monoxide was produced by the reaction of carbon dioxide and hydrogen formed.