STUDY OF CATALYTIC REDUCTION OF NOx IN FLUE GAS FROM A MUNICIPAL REFUSE INCINERATOR

近年来，在城市垃圾焚烧炉烟气等含催化毒物和粉尘的脏气体的净化实验中，应用了NOx催化还原技术。但在实际应用中存在催化性能下降、催化剂再生技术等问题。首先，在240ºC的反应温度下，以空气、CO2和NO为混合气体，研究了氨催化还原氧化氮的过程。催化剂为V2O5-TiO2球团，球团平均直径为5mm。进气体积浓度为O2 19%， CO2 7 ~ 9%, NO 100 ~ 140ppm，剩余氮气。实验研究了催化剂填充床长径比、停留时间、反应温度和通过反应器的线速度对NOx脱除效率的影响，并考察了反应速率常数的变化和NH3的泄漏量。其次，为了实现最节能的再生，研究了在400 ~ 600℃的温度下，在电炉上热处理2 ~ 6小时，获得了几个百分点的NOx脱除效率。根据催化剂的微孔体积、比表面积和Na、K、Ca、Fe的富集量的变化，讨论了催化剂的再生技术。

Recently the technique of the catalytic reduction of NOx has been experimentally used to clean dirty gas containing catalytic poisons and dust such as flue gas from a municipal refuse incinerator. However many problems such as deterioration of catalytic performance and regeneration technique for the catalyst remain unsolved for practical application.Firstly, we investigated the catalytic reduction process of nitrogen oxide with ammonia using a mixed gas of air, CO2 and NO at the reaction temperature of 240ﾟC. The catalyst used was V2O5-TiO2 pellets,and average diameter of pellets was 5 mm. The volumetric concentrations of inlet gas were O2 19%, CO2 7-9%, NO 100-140ppm and the remainder N2 gas. The effects of aspect ratio of the catalyst packed bed, retention time, reaction temperature and linear velocity through the reactor on the NOx removal efficiency were studied experimentally, and the change of reaction rate constant and the amount of leaked NH3 were also investigated.Secondary, in order to perform regeneration most energy conservatively, the heat treatment of 400 to 600ﾟC for 2 to 6 hours was studied using a electric furnace and the recovery of several percent of NOx removal efficiency was obtained. The regeneration techniques for catalysts are discussed on the basis of the results of the change of micropore volume, surface area and accumulation of Na, K, Ca, Fe in the catalyst.