高温还原性条件下煤焦孔隙结构的变化规律

研究了在高温还原性条件下煤焦的孔隙结构的变化规律。煤焦的制备在携带流反应器(entrained flow reactor，EFR)中进行。EFR能够模拟实际煤粉炉火焰区的温度和气相环境。氮气吸附和扫描电镜被用来描述煤焦的结构。由于高温还原性的气氛，气化反应对煤焦颗粒的孔隙结构和形态的影响不可忽略。根据孔隙结构和分形的分析，比表面积、孔容积、平均孔径和分形维数都有相同的变化趋势，并且煤焦的比表面积的变化可以归因于微孔的形成和变化。尽管如此，由于各种因素的存在，煤焦结构的变化规律是很复杂的。扫描电镜的照片显示了煤焦颗粒的不同形态是由于不同的煤显微组织和碳转化率。

Structure Development of Coal Chars Under High Temperature Reducing Conditions

The structure development of coal chars under high temperature reducing conditions was studied. The chars were produced in a high temperature entrained flow reactor (EFR) which can simulate the temperature and gas-phase environment in flame region of an industrial pulverized coal-fired furnace. Nitrogen adsorption and scanning electron microscopy were applied to characterize the char structure. The influence of gasification on the structure and morphology of the char particles can not be negligible due to the high temperature and reducing atmospheres. According to the pore structure and fractal analysis, it is concluded that the surface area, pore volume, mean diameter and fractal dimensions all have the same variation trends, and the surface area development of chars can be attributed to the formation and variation of micro-pores. Nevertheless, the char structure development is very complicated due to the existence of various competing factors. The scanning electron microscopy micrographs show that the different morphologies of char particles can be attributed to different maceral components and carbon conversion.