煤焦在CO_2气化过程中微孔结构的变化

VARIATION OF MICROSTRUCTURE OF COAL CHAR DURING GASIFICATION WITH CO_2

采用气相色谱技术,以CO_2为吸附质测定了用平鲁气煤、大同肥煤、山东瘦煤和晋城无烟煤制得的煤焦微孔比表面积及孔容分布。在阐明不同煤焦孔结构特征的基础上,数学关联了煤焦比表面积与转化率的关系。用SEM观察了气化反应中煤焦孔结构的变化过程,分析了气化过程中煤焦孔容分布的变化规律。

Microstructural properties, including specific surface area of coal chars at different stages in gasification with CO_2 were determined by gravimetric adsorption method using CO_2 as adsorbate. Four coals with widely different physical and chemical properties were chosen as the parent coals of the chars which were prepared in a unique high temperature and high pressure thermal gravimetric analyzer.The results indicate that among the four chars involved the micropore volume of Pinglu char and the specific surface area of Datong char show the largest value.The specific surface area of the chars with different conversion could be described by an expression of S=S_0(1-x)(1-Ψ(1-x))^(1/2). The morphology of Datong char with differeut conversion was examined by SEM technique.