煤气化半焦的孔隙结构

Pore structure of gasified coal-char

用氮气等温吸附(77K)方法测量了原煤及其加压、常压部分气化后半焦的BET比表面积,并通过BJH法计算了孔比表面积、孔容积、孔径和孔分布.结果表明,原煤在转化为半焦的过程中,孔隙结构变得发达,比表面积、孔比表面积和孔容积明显增大.实验发现半焦的孔比表面积和孔容积分布曲线存在2个明显的峰值,第1个尖峰对应的孔径稍小于2nm,说明微孔的比表面积大大增加;第2个尖峰对应的孔径在38nm左右,说明中孔的比表面积增加很快以至于出现了中孔的扩展.加压气化后的半焦孔隙结构更加发达,加压气化比常压气化更能促进半焦孔隙的生成和发展.

The coal-chars derived from atmosphere and pressurized partial gasification processes were measured by nitrogen adsorption principle at 77 K. Specific surface areas were determined based on BET model. Average pore size, total pore volume, pore specific surface area and pore size distribution were statistically obtained by using BJH theory. The results show that more abundant pores and larger specific areas and pore volumes are formed after partial gasification. Two peaks are found in distribution curves of the coal char pore specific surface area and pore volume; the first peak corresponds to a pore diameter of less than 2 nm, the second of about 3.8 nm. Gasification at elevated pressure can largely accelerate the pore formation. The pore development of coal-char at elevated pressure is more rapid than that at atmosphere condition.