煤与生物质混烧时可吸入颗粒物中的矿物质元素演变研究

Experimental Study on Transformation of Mineral Elements of Inhaled Particulate Matters During Co-combustion of Coal With Biomass

在沉降炉上进行了生物质与煤的混烧试验,分析研究了生物质与煤混烧时可吸入颗粒物的排放特性以及颗粒物中矿物元素的演变规律。试验条件如下:燃料给粉速度为0.3g/min,燃烧温度为1150℃,燃烧氛围分别为[N2]:[O2]=4:1和[N2]:[O2]=1:1,混合燃料中煤与生物质的质量配比始终保持为3:1。燃烧生成的颗粒物采用低压撞击器(LPI)按不同粒径大小从0.03μm～10μm分别采集,共分为13级。试验结果表明:4种燃料燃烧产生的颗粒物排放均为相似的双峰分布,粒径的峰值也都分别出现在0.1μm和4.3μm附近。4种混合原料在各工况下燃烧时,几种重要的单一矿物元素(包括其氧化物形式的成灰元素钙、磷,钠,硫以及痕量元素锌)在PM1.0(1.0μm以下颗粒物)和PM1.0+(1.0μm以上颗粒物)上的富集情况各不相同,并且随着氧气比例的增加颗粒物中各元素的浓度分布的变化趋势也有较大差异。

Co-combustion of coal with biomass was carried out in a laboratory-scaled drop tube furnace to investigate PM10 emissions. The combustion conditions were selected as follows： the raw material feeding rate was 0.3g/min, temperature was 1150℃, oxygen content was 20% and 50% respectively. The ratio of coal/biomass is kept at 75：25 （w%： w%）. Four fuel pairs were selected with respect to the mineral association within individual fuel. The results showed that the emitted inhaled PM from the co-combustion of biomass with coal had a bimodal distribution： one is at around 4.3μm and the other 0.1μm. During the combustion of four fuels at each condition, the enrichment of some important individual mineral elements （include the major oxide elements such as calcium, phosphorus, sodium, sulfur and trace elements like zinc） at PM1.0（below 1.0μm）and PM1.0＋（above 1.0μm）was different, and with the increasing of ratio of oxygen the concentration and emission of each element in the PM varied much.