钒钛基SCR催化剂中毒及再生研究进展

在烟气脱硝系统中,选择性催化还原催化剂的中毒和再生是广泛关注的问题。文章介绍了钒钛基催化剂的碱金属中毒、碱土金属中毒、砷中毒和二氧化硫中毒,探讨其成因,并对中毒机理进行了分析,同时研究了避免催化剂中毒的措施以及中毒催化剂的再生技术。对碱金属中毒和碱土金属中毒催化剂的水洗再生和硫酸酸洗再生方法进行了实验评价。文章对溶胶凝胶法制备的以陶瓷颗粒为骨架的纳米负载型催化剂V2O5-WO3/TiO2(C)进行研究。实验结果表明,硫酸酸洗再生对碱金属和碱土金属中毒催化剂具有较好的再生效果。在380～410℃温度范围内可使中毒催化剂的NO去除率恢复至90%以上。水洗再生对碱金属中毒催化剂无明显效果,而在380～410℃温度范围内可使碱土金属中毒催化剂的NO去除率达到80%以上。对V2O5-WO3/TiO2(C)抗SO2性能研究表明,以锐钛TiO2为载体的V2O5-WO3/TiO2(C)催化剂具有较好的抗SO2效果。

Deactivation and Regeneration of SCR Catalyst Based on V2O5-TiO2

Deactivation and regeneration of SCR catalysts have caught wide attention. Based on a comprehensive literature review,deactivation mechanisms of traditional SCR catalysts based on V2O5-TiO2 by alkali,alkaline earth,arsenic and SO2 were discussed. Measurements to avoid catalyst deactivation and method to regenerate the deactivated catalysts were proposed. Catalysts deactivated by alkali and alkaline earth were washed with water and sulfuric acid solution respectively and the regeneration effects were evaluated. Nano-TiO2/ceramic supported V2O5-WO3 catalysts (V2O5-WO3/ TiO2 (C)) prepared by sol-gel method was used as SCR catalysts. Results showed that the catalytic activity of V2O5-WO3/ TiO2 (C) deactivated by alkali and alkaline earth regenerated greatly by washing with sulfuric acid solution. NO conversion of both deactivated catalysts washed with sulfuric acid solution could reach above 90% over the temperature range 380～ 410℃. Activity of V2O5-WO3 / TiO2 deactivated by alkali was not improved after the deactivated catalysts being washed with water,while that of V2O5-WO3/TiO2 deactivated by alkali could reach above 80% over the temperature range 380～ 410℃ with the same regeneration method. Results also showed that V2O5-WO3/TiO2 (C) with TiO2 anatase phase as the support had good SO2 tolerance.