研究了煤焦的膨胀特性及其对1~5μm残灰颗粒物生成的影响.将一种烟煤筛分为小于63pm,[63~100)μm和[100-200)μm三种粒径,并在实验室沉降炉中进行了热解和燃烧实验.反应温度分别为1373K,1523K和1673K.利用激光粒度分析仪和扫描电子显微镜等对热解和燃烧产物进行了分析.研究结果表明,该种烟煤由于含有较高的镜质组成分,在热解过程中表现出明显的膨胀特性,而且煤粉粒径越小,其镜质组含量越高,因此在热解过程中膨胀越厉害,形成的煤胞型颗粒越多.膨胀厉害的煤焦在燃烧过程中很容易发生破碎,形成更多的1~5μm残灰颗粒物。
The swelling characteristics of coal chars and their influence on the formation of residual ash particles between 1- 5μm were studied. A bituminous coal was classified into they size fractions. They were less than 63μm, 63-100μm and 100-200μm, respectively. They were pyrolyzed and burnt at the temperatures of 1 373 K, 1 523 K and 1 673 K in a laboratory drop tube furnace. The ob- tained products were analyzed by a laser diffraction particle size analyzer and a scanning electron microscope. The results showed that this bituminous coal was possessed of obvious swelling in pyrolysis due to its high content of vitrinite macerals. The finer the coal particle size was, the greater the rela- tive degree of swelling and the more char cenospheres were formed. Coal chars with greater degree of swelling were easier to fragment during combustion and more residual ash particles between 1-5μm were produced.