燃煤水泥窑尾颗粒物粒径分布及污染特征

CHARACTERISTICS OF DISTRIBUTION AND EMISSION FOR FINE PARTICULATES FROM A CEMENT KILN TAIL

选取某4000t/d新型干法水泥生产线,采用低压撞击器进行颗粒物采样测试研究,分析颗粒物粒径分布及分级颗粒的化学成分。结果表明:悬浮预热器出口的ρ(PM10)为3.53g/m^3,其中PM1和PM2.5占PM10比例分别为29.4%和89.4%,且PM10为双峰分布,其峰值分别为0.1~0.2μm和1~1.8μm。窑尾飞灰中PM10成分地壳元素Ca、Fe、Si的含量较多,元素总和达到95.7%,生料破碎及残渣聚合决定粗模态分布特征,燃煤飞灰中S、K等易挥发元素的气化凝结决定细模态分布特征。烟气颗粒物经增湿塔后,ρ(PM10)由3.53g/m3降低至3.39g/m3,且呈单峰分布,峰值为2~2.5μm,表明增湿塔对烟气中细颗粒物具有凝聚和脱除效果。袋式除尘器对PM10的脱除效率在99.5%以上,且存在0.1~0.4μm的脱除逃逸窗口,增湿塔运行条件对布袋除尘的脱除效率无明显影响。

A Dekati low pressure impactor (DLPI) sampling system equipped with PM 10 cyclone was applied to measure the particle size distribution of the PM 10 from a 4000 t/d cement kiln.The chemical composition of the collected particulates were analyzed with XRD and XRF.The results showed that the mass concentration of the PM 10 emitted from the suspension preheater was 3.53 g/m 3, while the ratio of PM 1 and PM 2.5 to the PM 10 were 29.4% and 89.4%, respectively.The PM 10 presented a bimodal distribution, with the smaller peak size ranging at 0.1~0.2 μm and the larger peak size at 1~1.8 μm.From the composition of the fly ash, it was indicated that the curst element Ca, Fe, Si hold high proportion, summing up to 95.7%.The mass contribution of the ash mainly was derived from the crushing coarse particulate matter from raw material residues.And the gasification condensation of S, K and other volatile elements in coal-fired fly ash dominated the distribution of fine particle matter.The concentration of PM 10 decreased from 3.53 g/m 3 to 3.39 g/m 3 after the flue gas passing through the conditioning tower, and the distribution turned into unimodal with the peak size at 2~2.5 μm.The result indicated that the conditioning tower promoted the agglomeration and removal of the fine particulates.It was highly efficient for the fabric filter with the removal efficiency of PM 10 above 99.5%, while there was still an escape scope of 0.1~0.4 μm.The running parameters of conditioning tower had little influence on the efficiency of the fabic filter.