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采用共混热解法制备系列Ce-Sn-W-Ox复合氧化物,用于NH3选择性催化还原NO。通过正交实验优化CeSn-W-Ox配方,采用环境扫描电镜(ESEM)、X-射线衍射仪(XRD)等表征分析催化剂的微观形貌和固相结构,确立Ce-Sn-WOx最佳配比及结构形貌。结果表明,以粒度为5~8 mm的堇青石瓷片担载分散Ce-Sn-W-Ox,进行NH3-SCR脱除NO,当Ce/Sn/W元素摩尔比为1∶0.8∶0.6时,Ce Sn0.8W0.6Ox/堇青石NH3-SCR脱除NO效果最好。当空速为7 200 h-1,催化剂在252~426℃内脱除NO效率均大于94%。重点考察了反应空速(GHSV)、水蒸气(H2O)、SO2等对Ce Sn0.8W0.6Ox/堇青石NH3-SCR脱除NO活性的影响。研究表明,空速低于10 000 h-1时,催化剂脱硝活性受空速影响小;单独通入5%H2O对催化剂脱硝活性基本没有影响;单独通入429 mg/m3SO2导致催化剂活性略有降低;同时通入429 mg/m3SO2和5%H2O,催化剂脱硝活性下降至85.33%,除去SO2和H2O后,催化剂活性又能明显回升。
A series of Ce-Sn-W-Ox composite oxides were prepared by blended pyrolysis method for the selective catalytic reduction of NO by NH3. The CeSn-W-Ox formulation was optimized by orthogonal experiment. The morphology and solid-phase structure of the catalyst were characterized by using environmental scanning electron microscopy (ESEM) and X-ray diffraction (XRD) Than the structure and morphology. The results showed that Ce-Sn-W-Ox was dispersed in cordierite ceramics with a particle size of 5 ~ 8 mm and NO was removed by NH3-SCR. When the Ce / Sn / W molar ratio was 1: 0.8: 0.6 , Ce Sn0.8W0.6Ox / cordierite NH3-SCR removal of NO best. When the space velocity is 7 200 h-1, the removal efficiencies of NO at 252 ~ 426 ℃ are all above 94%. The effects of reaction space velocity (GHSV), water vapor (H2O) and SO2 on NO removal by Ce Sn0.8W0.6Ox / cordierite NH3-SCR were investigated. The results showed that when the space velocity was lower than 10 000 h-1, the activity of denitrification was little affected by the space velocity. The single pass of 5% H 2 O had no effect on the denitrification activity of the catalyst. When 429 mg / While 429 mg / m3 SO 2 and 5% H 2 O simultaneously, the activity of denitrification of the catalyst decreased to 85.33%. After SO 2 and H 2 O were removed, the activity of the catalyst rebounded obviously.