化学团聚促进电除尘脱除PM2.5的实验研究

燃煤排放细颗粒物是大气环境PM_2.5增加的重要来源。采用燃煤热态实验系统，进行了在电除尘器入口烟气添加化学团聚剂以及协同脱硫废水蒸发处理促进电除尘脱除PM_2.5的实验研究。实验考察了团聚剂添加前后PM_2.5浓度及其粒度分布的变化，以及团聚剂浓度、添加点烟温、团聚剂溶液pH、烟气量、雾滴粒径等对PM_2.5脱除效果的影响。结果表明，添加化学团聚液后，通过润湿作用、液桥力和吸附架桥作用可增强PM_2.5之间的接触并促进团聚长大，PM_2.5增大到原先的4倍左右，典型工况下电除尘器出口PM_2.5浓度降低40%以上。增加团聚液浓度可促进PM_2.5的脱除；适当降低团聚液pH有利于PM_2.5的团聚。喷脱硫废水，电除尘器出口PM_2.5浓度变化不大，加团聚剂后出口细颗粒物浓度降低。

Improving removal of PM2.5 by electrostatic precipitator with chemical agglomeration

Emission of fine particles from coal combustion is an important source of atmospheric PM_2.5. The removal of PM_2.5 from coal combustion by electrostatic precipitator (ESP) with adding agglomerant solution and evaporating treatment of desulfurized wastewater was investigated experimentally based on the coal-fired thermal system. Change of concentration and diameter distribution of particles were tested before and after agglomeration, and the influence factors, including concentration of agglomerant solutions, temperature of flue gas at the point of addition，agglomeration solution pH，flue gas flow, and diameter of spray droplets were analyzed. The average diameter of particles could grow more than four times with the effect of wetting, liquid bridge force and adsorption bridging, and the PM_2.5 concentration at ESP outlet could decrease by more than 40% under typical flue gas conditions. Increasing concentration of agglomeration solution could promote PM_2.5 removal. Reducing agglomeration solution pH was better for agglomeration by making the polymer chain more soft stretch. The PM_2.5 concentration at ESP outlet had no change after spraying desulfurized wastewater, and the PM_2.5 concentration decreased when adding agglomeration solution.