市政污泥与煤混烧的颗粒物生成特性

Formation Characteristics of Particulate Matters During the Co-combustion of Municipal Sewage Sludge and Coal

通过2种市政污泥分别和某电厂实际用煤混烧的实验,研究污泥的种类、掺烧比例(5%、10%、20%、50%)对混烧时颗粒物生成特性的影响。在沉降炉1400℃、空气气氛的燃烧实验结果表明:掺烧了污泥的样品能够从不同度上抑制PM_(1)的生成,燃煤单独燃烧时PM_(1)生成量为0.765mg/g,而掺烧了20%东、西污泥的样品PM_(1)的生成量分别为0.645mg/g和0.657mg/g。东污泥混烧后PM_(1)的生成量相比理论计算值有约20%的减排作用,主要是因为混烧时煤中的硅铝酸盐吸收污泥中易气化元素P、S、Cl使得生成PM_(1)的前驱物减少,而煤中细硅铝酸盐颗粒又会被污泥中Ca-Fe-P-Si-Al颗粒所捕获长大,造成了混烧时PM_(1)中的P、S、Cl、Si和Al含量与理论值相比有所降低。

In this paper,the effects of the types and the blended ratios(5%,10%,20%,50%)of sewage sludge on the formation characteristics of particulate matter during the co-combustion with coal were studied through the experiment of two kinds of municipal sewage sludge and a power coal used in a power plant.The combustion experiments at 1400℃and air atmosphere in a drop tube furnace showed that the PM_(1)formation could be inhibited by the co-combustion of sludge and coal.The PM_(1)formation was 0.765mg/g when the coal was combusted alone,and the PM_(1)formation was 0.645mg/g and 0.657mg/g when the east or west sludge samples were co-combusted with coal respectively at blended ratio of 20%.East sludge co-combustion resulted in about 20%of emission reduction of PM_(1),and it is mainly caused by not only aluminosilicates in coal react with vaporized element P,S,Cl to reduce the precursors forming PM_(1),but also by fine aluminosilicates in coal captured by Ca-Fe-P-Si-Al particles from sludge to grow up.These change caused the decrease of P,S,Cl,Si and Al content in PM_(1)during co-combustion compared with theoretical value and less formation of PM_(1).