Propylene Selective Catalytic Reduction Of Nitric Oxide

Selective catalytic reduction (SCR) of NO with hydrocarbon has become one of important projects. To find out an efficient catalyst is of great importance for the research. This research investigated the performances of C3H6-SCR of NO over Ag/γ-Al₂O₃ and CuO/γ-Al₂O₃ catalysts which were prepared by impregnation and the effects of Ag or CuO loading , O₂ content in feed gas, GHSV and temperature for catalyst calcination on NO conversion. The activity of catalysts was evaluated by fixed-bed micro-reactor equipment. The effects of supports including γ-Al₂O₃, SiO₂, Kaolin and CeO₂ on CuO/γ-Al₂O₃ catalyst were also researched. The results showed that γ-Al₂O₃ had the activity for NO reduction while SiO₂ and Kaolin had no activity for it. The activity of CuO/γ-Al₂O₃ catalyst was higher than CuO/ SiO₂ catalyst. CuO/Kaolin had no reaction activity at all. NO conversion of peak temperature of CuO/γ-Al₂O₃ was 100% and CuO/ SiO₂ was 80.15%. The effect of CuO loading of CuO/γ-Al₂O₃ catalyst on NO conversion was studied. The activity of the catalyst was higher and the reaction temperature was lower. The highest NO conversion was achieved over 16wt% CuO/γ-Al₂O₃ at lower temperatures whose range was wider than other catalysts. O₂ could increase NO conversion and the proper O₂ content was 0.428% . The research of temperature for catalyst calcination on the NO reaction activity showed that the fitting temperatures were 300℃and 400℃but NO conversion decreased when increasing the temperature from 600℃to 800℃. The effect of the addition of CeO₂ on CuO/γ-Al₂O₃ catalyst was also researched. Certain CeO₂ content could improve the thermal stability of CuO/γ-Al₂O₃ catalyst to some extent. The research over Ag/ γ-Al₂O₃ catalyst (0³wt.%) showed that the highest NO conversion was achieved while silver loading was 1.5wt.%. O₂ in the feed could promote the NO reduction over Ag/γ-Al₂O₃ catalyst through lowering the reaction temperature as higher reaction temperature makes C₃H₆ be oxygenated. The proper O₂ content was 0.27%.