抄録
Exhaust gas from a diesel engine is one of the main causes of air pollution. It is difficult to reduce NO under the excess O2 concentration so that effective method of NO reduction has not been developed. In this study, nickel on the porous glass (VYCOR® glass) was examined as a catalyst for NO reduction. This catalyst was effective for NO reduction where 35% of NO was converted to N2 under excess O2 concentration (3%) in the tubular fixed-bed reactor. Adsorption rates of NO and O2 gases were measured in order to examine the mechanism of selective reduction of NO by porous VYCOR catalyst. It was proved that NO adsorption rate was much higher than O2 adsorption rate, so that difference of adsorption rate was one of the main causes of NO reduction. As a short lifetime of the catalyst was the serious disadvantage of the tubular fixed-bed reactor, another type of catalytic reactor was proposed and tested. It is a membrane reactor consisting of a porous VYCOR catalyst tube and a quartz tube. NO reduction under excess O2 concentration was also achieved in the membrane reactor. Maximum conversion from NO to N2 was 45%. The possibility of longer lifetime catalyst could be found.
