内蒙煤焦CO2气化过程的结构演变特性

Structure evolution characteristics of Inner Mongolia coal char during CO_2 gasification

基于滴管炉制备内蒙褐煤快速热解焦,借助高频炉开展快速热解焦与CO_2的气化实验,考察了煤焦气化过程的结构演变特性。结果表明,随着反应的进行,气化半焦的石墨化程度不断增加,但未达到天然石墨的有序化程度;比表面积先增大后减小,而平均孔径总体呈相反的变化趋势;气化半焦的粒径在反应前期逐渐减小,当转化率大于74%,半焦粒径逐渐增大,归因于气化后期部分颗粒的黏结。

The rapid pyrolysis chars of an Inner Mongolia （Neimeng） lignite were prepared in a drop tube furnace, and the coal char gasification experiments with CO2 were conducted using a high-frequency induction furnace. The characteristics of char structure evolution during gasification were studied. Results show that as the reaction proceeds, the graphitization degree of gasified chars increases, but it is far less than the degree of natural graphite. The specific surface area firstly increases and then decreases with char conversion, while the average pore size has an opposite trend overall. The particle size of gasified chars gradually increases with conversion in the early stage, and the particle size of gasified chars increases w h e n the conversion exceeds 74 % , which could be ascribed to the cohesion of some particles in the later stage of gasification.