商用SCR催化剂催化生成SO_(3)特性

On the catalytic performance of commercial SCR catalyst for SO_(3) generation

选择性催化还原(SCR)设备可以有效脱除烟气污染物NO_(x),但也会催化生成SO_(3),从而危害设备安全和大气环境。本研究在模拟SCR实验台基础上考察了温度、烟气气氛和催化剂组分对SCR催化剂催化生成SO_(3)的影响,并采用X射线荧光光谱(XRF)和X射线光电子能谱(XPS)分析了催化剂在反应前后的变化。结果表明:温度升高会提高SO_(3)的生成率;O_(2)含量对SO_(3)的生成产生影响,但是O_(2)含量超过2%后影响微小;增大SO_(2)浓度会降低SO_(3)生成率,但SO_(3)总量仍不断提升;一定浓度的NH3显著抑制了SO_(3)的生成,同时产生大量硫铵盐沉积物,而NO_(x)中的氧化性气体NO_(2)会提高催化剂中V5+的比例,促进SO_(3)生成;实际反应过程中脱硝与SO_(2)氧化存在竞争,降低烟气中NO_(2)浓度会提升脱硝效率且减少SO_(3)生成;催化剂中的钒和钛会提高SO_(3)生成率,而硅对SO_(3)的生成有抑制作用。本研究为SCR的实际运行优化提供了一定的理论基础和参考。

Selective catalytic reduction(SCR)can effectively remove pollutant NO_(x) from flue gas,but it also catalyzes the generation of SO_(3),endangering equipment safety and atmospheric environment.In this study,the effects of temperature,flue gas atmosphere and catalyst components on the catalytic production of SO_(3) by SCR catalyst were investigated on a simulated SCR equipment.The changes of the catalyst before and after reaction were analyzed by X-ray fluorescence spectroscopy(XRF)and X-ray photoelectron spectroscopy(XPS).The results showed that the yield of SO_(3) increased with temperature and O_(2) content could affect the SO_(3) production,but the effect was minimal with O_(2) content over 2%.Increasing SO_(2) concentration decreased SO_(3) production rate,but total SO_(3) amounts still increased.At a certain concentration Industry and Engineering Progress,2023,42(12):6354-6362.of NH3,the formation of SO_(3) was significantly inhibited,and a large amount of sulfur and ammonium salt deposition was produced.However,the oxidizing gas NO_(2) in NO_(x) could increase the proportion of V5+in the catalyst and promote the formation of SO_(3).In the actual reaction process,denitrification competes with SO_(2) oxidation.Reducing the NO_(2) concentration in flue gas could improve the denitrification efficiency and reduce the generation of SO_(3).The vanadium and titanium in the catalyst could increase the formation rate of SO_(3),while the silicon could inhibit the formation of SO_(3).This study provides a theoretical basis and reference for the operation optimization of actual SCR.