Durability of a Ni based monolithic catalyst in the autothermal reforming of biogas

摘要

A Ni based catalyst supported on a cordierite monolithic substrate was applied to the autothermal reforming (ATR) of biogas to produce hydrogen. When the feed rates of oxygen and steam were constant, the Steam/CH_4 (S/CH_4) and O_2/CH_4 ratios changed because of an increase or decrease in the methane concentration of the biogas. The concentration of methane in the biogas fluctuates roughly between 35% and 65% according to factors such as the properties or amount of the waste. Therefore, the effect of S/CH_4 and O_2/CH_4 ratios on catalyst durability was confirmed by using actual biogas, which was produced by anaerobic fermentation of biomass at the biogasification bench-scale plant in Kyoto. Reforming reactions were carried out at ratios of S/CH_4 = 0-4, O_2/CH_4 = 0.5 and at S/CH_4 = 2, O_2/CH_4 = 0.6. The S/CH_4 range of 0-2.0 and the O_2/CH_4 range of 0.5-0.6 had no effect on the catalyst durability and a S/CH_4 ratio of more than 3.0 led to decreased catalytic performance.rnActual biogas contains minor components such as hydrogen sulfide, siloxanes and other organic materials. It was difficult to completely remove these compounds. The influence of these compounds was investigated during an experiment, which lasted for 250 h using actual biogas. We confirmed that the residual organic compounds had no effect on the catalytic activity, and that a stable performance was obtained under suitable conditions for the feed rate of steam and oxygen.