煤粉细度对一次颗粒物特性的影响研究

Coal Fineness Effect on Primary Particulate Matter Features During Pulverized Coal Combustion

以3种不同细度的煤粉在沉降炉中做燃烧实验,利用8级Andersen粒子撞击器分级并捕集燃烧后的一次颗粒物.研究煤粉细度对煤粉燃烧后一次颗粒物特性的影响.结果表明,煤粉越细,燃烧后生成的颗粒物也越细,PMi的排放量均随着煤粉细度的减小而增大,PM10的量由粗煤粉和中煤粉的13 mg/g左右增大到了细煤粉的21 mg/g;PM2.5的量由粗煤粉的2 mg/g增大到了细煤粉的8 mg/g.煤粉细度对煤粉燃烧后生成的总灰成分及含量影响不大,但对分级颗粒物的外观形貌影响较大.煤粉细度减小,痕量元素的REE增大.REE值大小的排列顺序依次为Pb>Cr>Zn>Cu>Ni.细煤粉生成的颗粒物中有毒痕量金属元素的含量更高.元素的挥发能力不受煤粉细度影响,但其挥发程度受煤粉细度影响却不同.细煤粉燃烧比粗煤粉燃烧具有更大的环境危害性.

Three kinds of coal differed from fineness were burned in a laboratory-scale drop tube furnace for combustion test,and an 8-stage Andersen particle impactor was employed for sampling the primary particulate matter（PM）,in order to study coal fineness effect on primary PM features during pulverized coal combustion.It has been shown that the finer the coal was,the finer the PM produced.PMi emission amount augmented with coal fineness decreased,and the amount of PM10 increased from 13mg/g to 21mg/g respectively generated by coarse coal and fine coal.The amount of PM（2.5） increased from 2mg/g to 8mg/g at the same condition.Constituents and content in bulk ash varied little after three different fineness coal combustion,while the appearance of grading PM differed visibly.The value of REE increased while the coal fineness deceased.The volatility of trace elements which were investigated was Pb〉Cr〉Zn〉Cu〉Ni in turn.The concentration of poisonous trace elements was higher which generated from fine co al combustion.The volatilization capacity was influenced little by coal fineness,but the volatilization extent was influenced differently by coal fineness.Fine coal combustion affects worse environment than coarse coal does.