Effects of coburning of municipal sludge and bituminous coal washery tailing on particulate matter emission characteristics under fluidized bed conditions
ZHANG Liu,JIA Li,WANG Yanlin,WANG Biru,ZHANG Jiadong,JIN Yan,XIANG Jun
污泥 / 煤泥作为高灰分低热值燃料,燃烧是大规模减量化处理以上 2 种物质的一种有效手 段,随着雾霾问题的日益严重,在此过程中需要特别关注其颗粒物的排放问题。 基于流化床实验 台,采用自行设计的颗粒物收集装置,并且利用 BT-9300HT 激光粒度分析仪和 X 射线荧光光谱 仪( XRF) 分别得到生成颗粒物的粒径分布和化学成分,揭示了污泥 / 煤泥单独燃烧和污泥 / 煤泥混 烧颗粒物的生成特性。 实验结果表明:污泥与煤泥在流化床中单独燃烧时颗粒物的粒径分布在 800 °C 前后表现出明显的变化差异,且 PM2.5 / PM10 体积分数排放量与粒径分布峰值一致,为焦油对 颗粒物的固定吸附作用、碱金属的熔融团聚作用与矿物质在燃烧过程中的气化、碰撞、破碎作用交 互影响所致。 燃烧产生的 PM2.5 主要成分为 K,Mg,S,Cl,P,PM10 主要成分为 Si,Al,Fe,Ca,且污泥 的 PM2.5 中 K,Mg,S,Cl,P 较煤泥高,煤泥的 PM10 中 Si,Al,Fe,Ca 较污泥高。 燃烧温度和污泥 / 煤泥 质量比会影响颗粒物的排放特性,其中燃烧温度的升高会导致粗模态颗粒物对应的峰值呈现向小 粒径方向且向上移动的趋势;不同质量比条件下颗粒物的实验值与线性加和值有明显差异,混烧明 显减少了燃烧后 PM2.5的排放量,原因在于燃烧过程中污泥中的易气化元素(K,Cl,P,S 等)与煤泥 中的矿物质与焦炭存在一定的交互作用。
The combustion of sludge/coal washery tailing as high ash and low calorific value fuel is an effective means of reducing the above two substances on a large scale,and with the growing problem of haze,particular attention needs to be paid to their particulate emissions in the process.Based on a fluidized bed test bench,using a selfdesigned particulate collection device,BT9300HT laser particle size analyzer and Xray fluorescence spectrometer(XRF),this study obtained the particle size distribution and the chemical composition of the generated particles respectively revealed the generation characteristics of the particles of sludge/coal washery tailing combustion alone,and sludge/coal washery tailing mixed combustion.The results show that when sludge and coal washery tailing[LM]were burned separately in a fluidized bed,the particle size distribution of particulate matter showed a significant difference at around 800 ℃,and the volume fraction emission of PM 2.5/PM 10 was consistent with the peak particle size distribution.It was caused by the interaction of the fixed adsorption of tar to particles,the melting and agglomeration of alkali metals and the gasification,collision,and fragmentation of minerals during the combustion process.The main components of PM 2.5 produced by combustion are K,Mg,S,Cl and P.PM 10 are mainly composed of Si,Al,Fe,Ca.The K,Mg,S,Cl,P in PM 2.5 of sludge are higher than that of coal slime,and the Si,Al,Fe,and Ca in PM 10 of coal washery tailing are higher than that of sludge.The combustion temperature and sludge/coal washery tailing blending ratio can affect the emission characteristics of particulate matter,the increase in combustion temperature leads to a tendency for the peak corresponding to coarse modal particulate matter to move in the direction of the small particle size and upwards.The experimental values of particulate matter under different blending ratio conditions differ significantly from the linear summation values,and blending significantly reduces the postcombustion PM 2.5 emissions,which was attributed to the interactions between the easily gasifiable elements(K,Cl,P,S,etc.) from the sludge and minerals and coke from the coal washery tailing during combustion.
sludge/coal washery tailing mixed combustion,PM,particle size distribution,PM 2.5/PM 10,interaction
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会