燃煤烟气中的SO_3对微细颗粒物电除尘特性的影响

Influence of SO_3 on Electrostatic Precipitation of Fine Particles in Flue Gas

采用BDL粉尘比电阻测定仪、巴柯粒度分析仪和COULTERTM SA 3100TM比表面积分析仪对某燃用准格尔煤电厂飞灰的比电阻、粒度及比表面积进行了分析,研究了烟气中SO3对微细颗粒物导电性能和团聚性能的影响.结果表明:在锅炉额定工况下当烟气中SO3的质量浓度增加约34.3 mg/m3时,飞灰比电阻降低约2个数量级,同时飞灰表面张力减小,黏附力增大,使得微细颗粒团聚为大颗粒,平均粒径增大,比表面积减小,从而使电除尘器效率明显提高.

Experimental tests have been performed to analyze the resistivity,size distribution and specific surface of fly ash particles from coal-fired power plants using BDL dust resistivity test instrument,Bahco particle size analyzer and COULTERTM SA 3100TM specific surface analyzer,so as to study the influence of SO3 on electrical conductivity and agglomerate property of fine particles in flue gas.Results show that when the mass concentration of SO3 rises by 34.3 mg/m3,the resistivity of fly ash will reduce by nearly 2 orders of magnitude under nominal load of boiler,which will result in reduced surface tension and specific area,increased adhesive force and mean particle size,and will therefore produce higher efficiency of dust precipitation.