失活钒钨钛脱硝催化剂的再生处理技术

Regeneration Treatment Technology of Deactivated Vanadium Tungsten and Titanium Denitration Catalysts

采用不同清洗再生工艺研究了热电厂运行3年左右的失活商业V_2O_5-WO_3/TiO_2催化剂再生效果。选用3种清洗液C1、C2和C3[即:清洗液C1为:去离子水;C2为:0.01 mol/L乙二胺四乙酸溶液(EDTA)+0.5 mol/L硫酸溶液(H_2SO_4)+0.5%十二烷基苯磺酸溶液(LAS);C3为:0.5%重金属捕捉剂2,4,6-三硫醇基钠硫代三嗪溶液(TMT103)]。设置了A、B、C3种清洗再生工艺[即:工艺A为清洗液C2+C3混合清洗;B为先用C2清洗再用C3清洗;C为先用C3清洗再用C2清洗],研究了失活催化剂整体式再生效果。结果表明:以去离子水为对照,在50 kHz的超声波下清洗时,清洗液C2和C3的最佳清洗时间分别为30 min和1 h,催化剂的NO_x转化率分别达到77%和79%。清洗工艺C对催化剂的清洗效果最佳,催化剂的NO_x转化率可达到85%。对工艺C清洗的催化剂进行活性组分补充,在活性温度窗口范围内(300～450℃)催化剂脱硝活性恢复到新鲜催化剂的水平。工艺C有效地去除了致毒元素,尤其是砷;恢复了催化剂表面孔结构,尤其是微孔结构;提高了催化剂表面Br?nsted酸、Lewis酸的酸量和强度,增强了催化剂的还原能力。

The regeneration of cleaning process of the deactivated commercial V2O5-WO3/TiO2 SCR catalysts used for 3 years at a power station was investigated by different cleaning regeneration techniques.Three kinds of cleaning fluids used were cleaning fluid C1 with deionized water,cleaning fluid C2:0.01 mol/L ethylene diamine tetraacetic acid(EDTA)+0.5 mol/L sulphuric acid(H2SO4)+0.5%dodecylbenzene sulfonic acid(LAS)and cleaning fluid C3:0.5%2,4,6-trimercaptotriazine(TMT103).The cleaning processes used involved cleaning process A– cleaned by a mixed cleaning fluid(i.e.,a volume ratio of cleaning fluid C2 to cleaning fluid C3 of 1:1),cleaning process B– cleaned by cleaning fluid C2 and then cleaning fluid C3,and cleaning process C–cleaned by cleaning fluid C3 and then cleaning fluid C2.The results show that with deionized water,the optimum cleaning time of cleaning fluid C2 and C3 are 30 min and 1 h at ultrasonic cleaning frequency of 50 kHz,leading to NOx conversion to 77%and 79%,respectively.NOx conversion can be 85%as using cleaning process C.NOx conversion can return to the fresh catalyst level at 300-450℃when the active components are added after cleaning by cleaning process C.It is revealed that cleaning process C can effectively remove the toxic elements(i.e.,arsenic),restore the surface pore structure of the catalyst(i.e.,micropore structure),enhance the amount and strength of the surface Br?nsted and Lewis acid sites,and improve the reducibility as well.