基于商用V2O5/TiO2催化剂,通过模拟SCR脱硝试验装置的宏观试验及原位傅里叶变换红外的微观分析手段,对SO2催化氧化机理及硫酸氢铵(ABS)的形成机理进行了研究.结果表明,SO2吸附在催化剂表面后先与V5+-OH基团反应生成了金属硫酸盐中间产物(VOSO4),继而转化为SO3,O2与温度都对该反应有促进作用.催化剂上ABS生成主要有2种机理:一是由吸附态NH3与气相或弱吸附态SO2反应生成;二是由金属硫酸盐(VOSO4)与气相NH3直接反应生成.催化剂上ABS大约在200 ℃生成,在450 ℃分解,且NO能与ABS中的NH+4反应而促进其分解,但此反应与脱硝反应共存且为竞争关系.%Based on commercial V2O5/TiO2 catalysts, the mechanism of SO2 catalytic oxidation and formation of ammonium bisulfate(ABS) were researched through macro-experiment on simulative experimental system of SCR DeNOx, combined with microscopic analysis methods of In situ Fourier transform infrared spectrometer(In situ FTIR).The results indicated that SO2 oxidation was that SO2 initially reacted with V5+-OH group on the catalyst surface after SO2 adsorption, for ming metal sulphate intermediate(VOSO4).In addition, the oxidation was accelerated by O2 and temperature.The source of ABS on V2O5/TiO2 catalysts had two paths: on one hand, it could be formed by the reaction between adsorption NH3 and gas phase or weak adsorption SO2;on the other hand, the reaction between metal sulphate(VOSO4) and gas phase NH3 could produce ABS.What`s more, the study suggested that ABS could form at 200 ℃ while decompose at 450 ℃ on V2O5/TiO2, approximately.
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