宽温脱硝催化剂性能试验研究

Experimental study on the performance of wide temperature denitration catalyst

煤电机组参与深度调峰时,脱硝系统入口烟温不能满足常规催化剂运行要求。为了实现全负荷脱硝,开展了宽温催化剂性能试验研究,以寻求宽温催化剂的质量评判参数。选取宽温催化剂和常规催化剂为研究对象,通过机械性能指标(检测抗压强度、磨损率)、理化性能指标(主要化学成分、微量元素成分、比表面积)及工艺性能指标(活性衰减率、活性恢复率、活性比)等指标,对比分析常规催化剂与宽温催化剂指标的区别。结果表明,作为主要活性组分的V_(2)O_(5)在宽温催化剂与常规催化剂中含量分别为1.475%和0.813%,而改性剂MnO_(2)为前者(7.448%)多于后者(0.825%);在经过含SO_(3)+NH_(3)的烟气钝化20 h后比表面积衰减量为12.351m^(2)/g和20.413m^(2)/g、工艺活性衰减率为43.02%和55.52%;260℃和380℃工况下活性比为61.76%和44.59%,结果存在明显差异。宽温催化剂的检测指标值均优于作为对比的常规催化剂。研究选取的宽温催化剂更高的钒含量在较大温度范围内可维持较高的催化活性,宽温催化剂在低温区域催化能力的提升主要靠活性组分和助剂MnO2的添加,钝化失活后常规指标的变化率即活性恢复率和低高温下催化剂脱出氮氧化物能力比值(活性比)可以有效评价宽温催化剂在工况变动时的适应能力,可作为评判宽温催化剂是否满足要求的相关参数,为达到机组低负荷运行状态时出口氮氧化物控制要求和满足并网深度调峰的燃煤电厂采选宽温催化剂提供参数参考。

When coal fired units participate in deep peak shaving,the flue gas temperature at the inlet of denitration system cannot meet the operation requirements of conventional catalysts.In order to realize full-load denitration,the performance test of wide-temperature catalyst was carried out to find the quality evaluation parameters of wide temperature catalyst.The current commercial wide temperature catalysts and conventional catalysts were taken as the research objects.The differences of them are compared and analyzed through mechanical performance indicators(compressive strength and wear rate),physical and chemical performance indicators(main chemical components,trace element components,specific surface area)and process performance indicators(activity decay rate,activity recovery rate,activity ratio)in order to find the quality evaluation parameters of wide temperature catalysts.The results showed that the contents of V_(2)O_(5)as the main active component were 1.475% and 0.813% in wide temperature catalyst and conventional catalyst,respectively.The content of MnO2as the former(7.448%)was higher than that of the latter(0.825%).After the passivation of flue gas containing SO_(3)+NH_(3)for 20 h,the attenuation of specific surface area is 12.351 m^(2)/g and 20.413 m^(2)/g,and the decay rate of process activity is 43.02% and 55.52%.At two temperatures(260℃ and 380℃),the activity ratio was 61.76%and 44.59%,and the results were significantly different.The detection values of the above indicators of the wide temperature catalyst were better than those of the conventional catalyst.The catalyst selected in this study has a higher vanadium content,which can maintain a higher catalytic activity in a wide temperature range.The improvement of the catalytic capacity of the wide temperature catalyst in the low temperature region mainly depends on the addition of active components V2O5and auxiliary MnO2.The change rate of conventional indexes after passivation and deactivation and the ratio of catalyst’snitrogen oxide removal capacity at low and high temperature can effectively evaluate the adaptability of the catalyst under changing working conditions.It can be used as the relevant parameters to judge whether the catalyst meets therequirements.This paper provides a reference for the parameters of wide temperature catalyst for coal power plants that meet the requirements of nitrogen oxide control at the outlet when the unit runs under low load and meet the requirements of peak regulation at the depth of grid-connection.