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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 flue gas denitrification technology, it is very important to reduce the deactivation rate of catalyst and prolong the life of catalyst to reduce the operating cost of SCR system.Description of the deactivation of SCR catalyst involved in the domestic and foreign literature, The factors that led to the deactivation of the catalyst were compared, and the influencing rules and factors of alkali metals, alkaline earth metals, As and P and HCl were compared. Based on the above, the poisoning mechanisms mentioned in various literatures were summarized: alkali metal By reducing the number of Bronsted acid sites and weakening the acidity of the Bronsted acid sites, the catalyst is poisoned. Alkaline earth metals can deposit on the surface of the catalyst resulting in blockage of the pore structure. The arsenic poisoning of the catalyst is caused by the continuous accumulation of gaseous arsenic compounds and clogging into the catalyst Active sites, while the effect of phosphorus on the catalyst is reflected in its ability to reduce the number of active sites.According to a specific mechanism of inactivation, the catalyst deactivation rate can be slowed by optimizing the properties of the catalyst.