干燥后褐煤的物理结构变化

Physical Structure Changes of Lignite after Drying

从微观角度研究了褐煤在不同干燥温度时物理结构的变化。发现褐煤的孔结构尺寸在干燥过程中发生了显著变化,随着干燥温度的升高,褐煤的比表面积逐渐升高,孔隙率和孔容增大,而孔径减小。比表面积和塌陷程度都随着干燥温度的升高而呈现明显增加的趋势,但在干燥温度为 210℃表现出下降趋势。干燥温度的升高导致大孔和中孔的明显转化和坍塌,而煤表面微孔的数量和分布变化不明显。经过干燥处理后的褐煤表面结构比原煤更粗糙,且其表面上出现众多的裂纹和管状通道,为水分的析出提供通道。

The changes of physical structure of lignite at different drying temperatures were studied from the micro point of view.It is found that the pore structure size of lignite changes significantly during drying.With the increase of drying temperature,the specific surface area of lignite increases gradually,the porosity and pore volume increase,and the pore size decreases.The specific surface area and collapse degree increased significantly with the increase of drying temperature,but decreased at 210 ℃.The increase of drying temperature leads to the obvious transformation and collapse of macropores and mesopores,while the number and distribution of micropores on the coal surface do not change obviously.The surface structure of lignite after drying is coarser than that of raw coal,and there are many cracks and tubular channels on its surface,which provide channels for water precipitation.