摘要
催化剂是SCR烟气脱硝技术的核心,减缓催化剂的失活速率,延长催化剂的寿命对于降低SCR系统的运行成本有着非常重要的意义.描述了国内外文献中涉及的SCR催化剂的失活现象,列举了导致催化剂失活的各项因素,比较了碱金属、碱土金属、As和P及HCl等物质的影响规律及因素,并在此基础上总结了各类文献中提到的中毒机理:碱金属通过减少Bronsted酸性位的数量和削弱Bronsted酸性位的酸性导致催化剂中毒,碱土金属则能够在催化剂表面沉积进而造成孔结构的堵塞,催化剂的砷中毒是由气态的砷的化合物不断聚积,堵塞进入催化剂活性位的通道引起的,而磷对于催化剂的影响体现在其能够减小活性位的数量上.针对特定的失活机理,可以通过优化催化剂的特性来减缓催化剂的失活速率.
Catalyst is the core of SCR de-NOx technology, to decrease the deactivation rate and prolong catalyst life has significant meanings on decreasing the operation cost of SCR system. This paper has described the phenomenon of catalyst deactivation, given all the influence factors of deactivation, specialized effects of alkaline metal, alkaline-earth metal, As, P, Pb and HC1 on SCR catalyst, and based on the effects, deactivation mechanism is discussed. The conclusions are that alkaline metal could decrease the quantity of Bronsted acid sites and change surface acidity of Bronsted active sites, alkaline-earth metal could block the pore structure of the cata- lyst, deactivation of arsenic is caused by accumulation of gaseous arsenic compounds, and phos- phorus has obvious effects on catalyst active sites. Aimed at specific deactivation mechanisms, we can optimize catalyst performance to decrease the deactivation rate.
出处
《煤炭转化》
CAS
CSCD
北大核心
2009年第1期91-96,共6页
Coal Conversion
基金
国家863重点基础研究资助项目(2006AA06A304)
关键词
SCR
催化剂
失活
SCR, catalyst, deactivation
