温度及盐酸浓度对改性SCR催化剂汞氧化能力的影响

Effect of temperature and hydrochloric acid concentration on mercury oxidation ability of modified SCR catalyst

采用V、Ce活性溶液浸泡的方法对常规SCR催化剂进行改性,分析了HCl浓度、温度对其汞氧化能力的影响。结果表明,和常规催化剂相比,V改性催化剂样品中V2O5含量增大、比表面积和孔结构大幅下降,其汞氧化率低;Ce改性催化剂中新增活性物质CeO2、比表面积和孔结构略微减小,其汞氧化能力增强;各样品中的TiO2晶型均为锐钛型、活性物质分散均匀。烟气中含HCl时,催化剂氧化单质汞的机理类似Deacon途径,随着温度的升高,汞氧化率先增大后减小,最佳汞氧化温度为350℃;在温度200～400℃,HCl浓度0～60μL/L时,汞氧化率随着HCl浓度的增加而快速增加,在HCl浓度>60μL/L时趋于饱和。

The common SCR catalysts were quality changed by vanadium salt solution and cerium salt solution,and the effect of HCl concentration and temperature on the modified catalyst's mercury oxidation ability was investigated.The results showed that,compared with the general catalyst,the V2O5content in V modified catalyst increased,while the catalyst's specific surface area and pore structure decreased sharply,the mercury oxidation efficiency was lower;a new active matter CeO2appeared in the Ce modified catalyst,the catalyst's specific surface area and pore structure decreased a little,the mercury oxidation ability enhanced;the titanium dioxide in three samples were all anatase titanium dioxide and the active matters were uniformly distributed.The mercury oxidation mechanism was approximate as the Deacon process when HCl existed,and with an increase in temperature,the mercury oxidation efficiency first increased then decreased,the best mercury oxidation temperature were 350 ℃;within temperature range of 200to 400 ℃,the mercury oxidation efficiency increased rapidly with HCl concentration ranging from 0ppm to 60ppm,and tended to be saturated when HCl concentration was above 60ppm.