SCR氮氧化物脱除系统对燃煤烟气汞形态的影响  

Influence of the SCR(Selective Catalytic Reduction)-based NO_x Removal System on Mercury Morphology in Coal-fired Flue Gas

作　　者：胡长兴[1] 周劲松[2] 何胜[2] 骆仲泱 

机构地区：[1]浙江大学宁波理工学院,浙江宁波315100 [2]浙江大学能源清洁利用国家重点实验室,浙江杭州310027

出　　处：《热能动力工程》2009年第4期499-502,共4页Journal of Engineering for Thermal Energy and Power

基　　金：国家自然科学基金资助项目(50476056);国家重点实验室开放基金资助项目(ZJUCEU2007006)

摘　　要：通过标准安大略方法测试分析了某300MW机组的选择性催化还原(Selective Catalytic Reduction,SCR)脱硝系统前后烟气汞形态分布,结合SCR反应脱除氮氧化物(NOx)的化学原理,着重研究了SCR系统对燃煤烟气汞形态的影响。研究表明,SCR催化剂(V2O5-WO3(MoO3)/TiO2)对烟气中的汞的吸附作用较小,不影响烟气总汞浓度。但经SCR后,气态汞的形态发生了较大的改变,Hg0浓度从49.01%降至7.30%;而Hg2+浓度由38.96%上升至82.67%。SCR系统中的NH3对汞形态转化没有作用,主要通过系统催化作用下的Cl-Deacon反应和中间体(氧化汞)完成HCl对Hg0氧化,最终形成HgCl2。By adopting the standard Ontario method,measured and analyzed were the morphological distribution of mercury in flue gas before and after the selective catalytic reduction(SCR) denitrification system of a 300 MW unit.In combination with the chemical theory for SCR reactions to remove NOx,the influence of a SCR-based denitrification system on the mercury morphology of coal-fired flue gas was studied as a key problem.It has been found that the SCR catalyzer(V2O5-WO3(MoO3)/TiO2) plays a relatively small role of adsorbing the mercury in flue gas and has no influence on the total mercury concentration in flue gas.However,after a SCR,the mercury morphology in gas state underwent a relatively great change with the HgO concentration decreasing from 49.01% to 7.30% while the Hg2+ concentration increasing from 38.96% to 82.67%.The NH3 in the SCR-based denitrification system plays no role in transforming the mercury morphology.The oxidation of HgO by HCl was mainly completed through the Cl-Deacon reaction and the intermediate(HgO) under the catalytic action of the system and,eventually,HgCl2 was formed.

关 键 词：燃煤 汞 形态 SCR 催化氧化 

分 类 号：TQ534[化学工程—煤化学工程] X701[环境科学与工程—环境工程]