SCR催化剂中毒因素实验研究

Study on SCR Catalyst Poisoning Factor

作为脱硝系统的核心,脱硝催化剂的活性下降成为决定整个脱硝系统运行成本的关键因素。而中毒是催化剂活性下降的主要原因,以北京某电厂不同运行时间段的脱硝催化剂为研究对象,通过活性评价及性能表征,对其主要中毒因素进行了实验研究,发现K、Na、Ca及As中毒是该电厂脱硝催化剂中毒的主要原因。其中,K、Na、Ca通过与催化剂的部分酸性位结合,使得催化剂与烟气有效接触面积减少,可用活性位减少,从而使得催化剂中毒;As则是先生成As2O3进入催化剂微孔,使得催化剂活性位被覆盖,烟气无法到达活性位反应,催化剂活性降低。

As the core of denitration system, decline of denitration catalyst＇ s activity becomes a key factor of thewhole denitration system＇ s process cost. And poisoning is the main reason for the catalyst activity＇ s decline. In thispaper,we choose the denitration catalyst in different running time of a certain power plant in Beijing as the researchobject,and make a research on the main factors of catalyst poisoning by activity assessment and characterization. Wefound that denitration catalyst poisoning in the power plant is mainly caused by K, Na, Ca, and As. Among them, K,Na,Ca make the catalyst poisoning by combining with some acid sites of the catalyst, reducing the effective contactarea between the catalyst and the flue gas,and reducing available active sites,however,As203 is firstly produced byAs,then entering the catalyst＇ s pores,which covered the active sites of the catalyst, and the flue gas can not reachactive sites to react ,thus, the catalyst activity is decreased.