REACTION PERFORMANCE OF METHANATION OF CARBON-MONOXIDE AND CARBON-DIOXIDE OVER SUPPORTED RUTHENIUM CATALYSTS - MAINLY ON EFFECTS OF REMAINING CHLORINE AND DECHLORINATION

To establish a catalytic process for the methanation of CO or CO2 with H-2, Ru catalysts supported on ZrO2, TiO2, Al2O3(theta) and SiO2 were prepared, and the relationship between the reaction condition and the catalytic reaction performance was investigated, especially from as to the effects of remaining chlorine in catalysts and dechlorination based on raw salt of Ru (RuCl3.4H2O), with the temperature swing reaction (TSR), the temperature-programmed reaction (TPR) method and at a constant temperature. Experiments were carried out using a flow fixed-bed reactor under an atmospheric pressure at mainly 120-degrees-350-degrees-C. The inlet gases were 10%CO-30%H2-N2 and 10%CO2-40%H2-N2, the total flow rate was 250 cm3N.min-1 per 0.5 ml of each catalyst with average diameter of 1.0 mm, and the space velocity was 3.0 x 10(4) h-1. The main results obtained were as follows. 1) The remaining chlorine after reduction of catalysts with H-2 was removed as HCl, the order of the amount being ZrO2 > SiO2 > Al2O3(theta) > TiO2, and that after washing with warm water (85-degrees-C) being SiO2 > ZrO2 > Al2O3(theta) > TiO2. 2) The effect of remaining chlorine on the catalytic activity was much larger for CO2 -methanation than for CO-methanation. 3) The remaining chlorine suppressed the formation of carbonaceous species on the catalyst surface and decreased the catalytic activity. 4) Ru/ZrO2 dechlorinated with warm water-washing (85-degrees-C) was the most active among the catalysts used in this study.