燃煤烟气低温NH3-SCR脱硝工艺中试

Pilot test on low temperature NH3-SCR denitration of coal-fired flue gas

国内对于低温脱硝催化剂的研究主要集中在实验室的小试规模,对无钒低温NH3-SCR蜂窝催化剂在燃煤烟气条件下的脱硝活性和中毒机理研究较少,无法完全反映出催化剂在真实烟气条件下的运行状况。本文采用自行设计的低温NH3-SCR装置在石河子市某热电厂进行了中试研究,得到了该催化剂在实际烟气条件下的最佳工艺条件,并深入分析了实际烟气中复杂成分对低温脱硝催化剂的影响机理。研究结果表明:SO2浓度低于35mg/m3、空速约为4200h-1、烟气温度约为100℃、氨氮比约为1.2时催化剂的脱硝效率最佳;高浓度的SO2会促进硫酸盐类的形成和催化剂活性组分的硫酸化,是催化剂活性降低的主要原因。环境友好型低温脱硝催化剂表现出优异的低温脱硝性能和抗硫性能;脱硝工艺改造方便;具有广阔的工业应用前景。

The researches on low temperature denitrification catalysts in China are mainly focused on laboratory scale test.On the other hand,the researches on the denitrification activity and poisoning mechanism of non-vanadium low-temperature NH3-SCR(selective catalytic reduction)honeycomb catalyst under coal-fired flue gas conditions were insufficient,and the experiments with simulated flue gas cannot fully reflect the performance of the catalyst under real flue gas.A self-designed lowtemperature NH3-SCR device was used in the pilot test at a thermal power plant in Shihezi.The optimal process conditions of the catalyst under actual flue gas were obtained,and the influence mechanism of complex components on the catalyst was analyzed in-depth.The results showed that the catalyst had the best denitration efficiency when the SO2 concentration was below 35mg/m^3,the space velocity was about 4200h-1,the flue gas temperature was about 100℃and the ammonia nitrogen ratio was about 1.2.High concentration of SO2 will promote the formation of sulfates and the sulfation of the active components in the catalyst.The low-temperature denitration process and catalyst have broad industrial application prospects because the process is easy to modify and the low-temperature denitration catalyst is environment-friendly and shows excellent denitration performance and sulfur resistance.