化学团聚剂强化燃煤细颗粒物团聚脱除

REMOVAL OF FINE PARTICLES FROM COAL COMBUSTION WITH CHEMICAL AGGLOMERATION AGENTS

燃煤细颗粒物对大气环境和人体健康均会产生严重影响,化学团聚是促进细颗粒形成大粒径团聚体而易被常规除尘器捕获的重要方法。化学团聚技术中团聚剂的组成是影响细颗粒物团聚效果的重要因素。由表面活性剂、无机盐和高分子絮凝剂构成多元团聚剂体系,经雾化形成液滴喷入细颗粒物团聚室,研究其对细颗粒团聚促进作用的影响。研究表明:选用含有无机盐的二元团聚剂体系均对细颗粒团聚有良好的促进作用,吐温-80体系对细颗粒物的清除效率可达44.1% 随着团聚剂溶液浓度的增加,细颗粒物的清除效率不断提高,阳离子型团聚剂体系对细颗粒物团聚的促进作用优于阴离子型团聚剂体系 团聚剂体系中无机盐,特别是氯化铵,能有效提高细颗粒清除效率 调节团聚剂体系的pH为弱酸性更有利于细颗粒的团聚。三元团聚剂体系各组分的协同作用可使颗粒间的黏附力提高3.5倍,团聚后细颗粒物的质量减少45%~49%,中位粒径由3.5μm增加至7.5~8.6μm。

Fine particles from coal combustion have a serious impact on human health and atmospheric environment.Chemical agglomeration technology could help the agglomeration of fine particles to form large aggregation which were captured easily by conventional precipitator.The constituents of chemical agglomeration agents affected greatly the removal efficiency of fine particles.A multi-components chemical agglomeration agent including surfactant,polymer flocculant and inorganic salt was atomized and ejected into the agglomeration chamber to increase the agglomeration of fine particles.The experimental data showed that the two-component agglomeration agent containing inorganic salt and surfactant or flocculant could increase the removal of fine particles.The maximum efficiency in Tween-80 mixture was 44.1%.The increment of the concentration of agglomeration agents could benefit for the removal of particles,especially for positively charges surfactant or flocculant.However,high concentration of flocculant resulted in high viscosity of solution,consequently forming large spray droplet and decreasing the number of droplet,which could not favor the agglomeration process.For the surfactants,high concentration could result in their remains in emission due to the small molecule structure.The concentration of agglomeration agent should be controlled detailed.The removal efficiency of fine particles could be further improved as the inorganic salt,especially when ammonium chloride was added.And high concentration of slat favored this process.The optimum pH value at which the removal was maximum was in weak acid range.The adhesive force among particles increased by 3.5 times when three-component chemical agents were used to remove particles.Therefore,the mass of fine particles reduced by 45%~49%,and the median diameter increased from 3.5μm to 7.5~8.6μm.