摘 要：为减少燃煤电站PM2.5的排放量，采用燃煤飞灰化学团聚热态系统，以燃煤电站飞灰为研究对象，在模拟烟气中进行添加化学团聚剂的实验研究，综合考察团聚剂添加前后PM2.5体积分布和微观形貌变化，以及团聚剂浓度、烟气浓度、pH值、停留时间、雾化液滴粒径和添加点温度对团聚效果的影响。结果表明：表面活性剂浓度为0.025%时团聚效果最佳，添加团聚剂后通过润湿作用、固桥力，可增强PM2.5和大颗粒之间的结合性能，有利于形成超大团聚体，标准工况下PM2.5团聚效率可达90%以上；增加团聚剂浓度可促进PM2.5团聚；团聚剂添加量要与烟尘浓度相适宜；适当降低团聚剂的pH值有利于PM2.5团聚；布置化学团聚系统时要综合考虑停留时间、雾化液滴粒径及添加点温度的影响，以免化学团聚剂蒸发不完全。

Abstract:In order to reduce the emission of PM2.5 in coal-fired power plant,in this paper,an experimental study on adding chemical agglomeration agent in simulated flue gas was carried out by using chemical agglomeration thermal system of coal-fired fly ash,with the fly ash as research object.The volume distribution and microstructure of PM2.5 before and after adding the agent was studied.Meanwhile,the effects of agglomeration agent concentration,flue gas concentration,pH,residence time,atomization droplet size and the temperature of agent adding point on chemical agglomeration were investigated.The results showed that,the agglomeration effect is the best with the agent concentration of 0.025%.After adding agglomeration agent,through the wetting effect and solid bridge force,the binding performance between PM2.5 and larger particles can be enhanced,and that is conducive to the formation of even larger aggregates.Under the standard condition,the agglomeration efficiency can be more than 90%.In addition,increasing agent concentration can promote the agglomeration of PM2.5.The amount of agent added should be appropriate to the concentration of soot.Properly lowering the pH of the agent enhances PM2.5’s agglomeration.Additionally,when the chemical agglomeration system is arranged,the residence time,the size of the atomized droplet and the temperature of the agent adding point should be considered to avoid the incomplete evaporation of the chemical agglomerants.

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