燃煤电厂砷中毒SCR脱硝催化剂再生技术研究

Research on Arsenic Poison of the SCR Catalyst Regeneration Technology in Coal-fired Power Plant

对燃煤电厂砷中毒SCR(Selective Catalytic Reduction:SCR)脱硝催化剂中毒机理及砷中毒催化剂再生技术进行了研究,提出了砷中毒催化剂中毒机理及我国燃煤电厂砷中毒SCR催化剂再生的影响因素。研究表明:催化剂砷中毒主要由烟气中的As_2O_3(g)引起,As_2O_3(g)扩散进入催化剂,吸附于催化剂的V^(5+)-OH及Ti^(4+)-OH吸附酸性位上并发生反应,其生成物占据原催化剂的活性位,从而导致催化剂中毒;通过对砷中毒催化剂进行再生实验发现,酸性清洗液对砷中毒催化剂活性恢复效果明显,用浓度5%的H_2SO_4同时结合活性负载物及高温煅烧对砷中毒催化剂进行处理,既保证了低的V浸出率,活性恢复到新催化剂的98%左右。最后,对燃煤电厂催化剂砷中毒的预防措施进行了总结。

The mechanism of arsenic poison of the Selective Catalytic Reduction （SCR） DeNOx Catalyst in coal-fired power plants were studied. Studies have shown the factors that influence the arsenic poison of catalyst＇s mechanism and the arsenic poison of the SCR catalyst regeneration. It also showed that arsenic poison of the catalyst is mainly caused by As203 （g） in flue gas. As203 （g） diffuses into the catalyst, adsorbs on V5^＋ -OH and Ti^4＋ -OH acid sites of the catalyst, then reacts in acid sites of catalyst, and the product of which occupies the original catalyst＇ s active sites, resulting in catalyst poisoning. After regeneration experiment on arsenic poison of catalyst, it was found the acidic cleaning solution to the arsenic poisoning of catalyst activity recovery effect is obvious. Using HE SO, with concentration of 5 % and activity load and high-temperature calcinations to process the arsenic poison of the catalyst, which not only ensure the low V leaching rate but also make the activity restoring to 98% of new catalyst. Finally, the precautions about arsenic poisoning are summarized.