脱硝催化剂碱(土)金属中毒机制及抗中毒方法研究进展

Recent advances in the research on the poisoning mechanisms and anti-poisoning methods of alkali(earth)metal for denitrification catalysts

氮氧化物作为多种燃烧过程的副产物,长期以来对环境和人类健康产生了不利影响。为了从源头上减少氮氧化物的排放,选择性催化还原(SCR)脱硝技术因其高效成熟的技术特性而被广泛应用。然而,在燃烧过程中产生的碱金属和碱土金属会对SCR催化剂产生不利影响,导致脱硝性能下降。因此,深入研究碱金属对SCR催化剂的中毒机理和抗中毒策略对于延长催化剂的使用寿命并降低运行成本至关重要。系统梳理了碱金属对多种SCR催化剂中毒的机理,并总结出碱金属主要通过化学中毒和物理中毒过程影响催化剂的性能。同时,概述了提升SCR催化剂的抗碱金属中毒能力的相关研究进展,包括催化剂改性、合理设计催化剂结构以及有效利用催化剂载体等方法。在综合考虑催化剂实际应用场景的基础上,阐释了烟气中碱金属与SO_(2)、重金属等成分对催化剂的共同毒害影响,并展望了催化剂的协同抗性研究。

As a by-product of many combustion processes,NO x has long affected the environment and human health.In order to reduce NO_(x) emissions at the source,selective catalytic reduction(SCR)denitrification technology has been widely used due to its high efficiency and mature technology characteristics.However,the alkali and alkaline earth metals generated during the combustion process can adversely affect the SCR catalysts,resulting in a decrease in its denitrification efficiency.Therefore,it is important to study the poisoning mechanisms of alkali metals on SCR catalysts and develop effective anti-poisoning strategies to extend the catalyst lifespan and reduce operational costs.This paper systematically examines the poisoning mechanisms of alkali metals on various SCR catalysts,concluding that alkali metals mainly affect the catalyst performance through chemical and physical poisoning processes.Additionally,an overview is provided on research progress in catalyst modification,rational catalyst structure design,and effective use of catalyst carriers to enhance the resistance of SCR catalysts against alkali metal poisoning.Considering real-world catalyst application scenarios,the paper also explains the joint poisoning effects of alkali metals,SO_(2),heavy metals and other components in flue gas on catalysts,while prospecting for future research on synergistic catalyst resistance.