可溶有机质对煤低温氧化的影响

Effect of soluble organic matter on the low-temperature oxidation of coal

为了揭示煤中可溶有机质对煤自燃的影响规律,利用红外光谱和GC/MS实验测试了经四氢呋喃抽提后煤表面微观结构变化及抽提产物成分,结合可溶有机质影响煤体孔隙结构的测试结果,在研究抽提前后煤体的低温氧化气体产物释放规律的基础上,探讨了可溶有机质对煤表面活性结构和煤低温氧化规律的影响。结果表明,抽提后残煤的羟基和羧基碳的含量降低,含氧量高且性质活泼的侧链及官能团减少,矿物质含量下降;煤中可溶有机质含有大量的甲基、羟基、羰基、醚基等活性基团;残煤总孔体积和比表面积均有不同程度的增加,平均孔径由原煤的6.3 nm减小至4.9 nm;抽提残煤在低温氧化阶段的耗氧量明显低于原煤,且CO,CO2,C2H4和C2H6气体的释放量较原煤有不同程度的降低,可见可溶有机质的存在对煤自燃有较大的促进作用。

In order to reveal the soluble organic matter effect on the spontaneous combustion of coal, the infrared spec- troscopy and GC/MS experiments were used to test the changes of coal surface mierostructure and product ingredients after extracted by tetrahydrofuran. Based on the results of soluble organic matter affect the pore structure of the coal, and according to the gas-product release law of low temperature oxidation of coal before and after the extraction, effect of soluble organic matter of the coal on surfaetant structure and low temperature characters of coal oxidation was dis- cussed. The results indicate that after extraction, the content of hydroxyl and carboxyl in residual coal is reduced. Meantime, mineral content and active side chains and functional groups which involve high-content oxygen in coal also reduce. Coal soluble organic matter contains a large amount of the active groups, such as methyl, hydroxyl, earbonyl and ether etc. The total pore volume and surface area of the residual coal is increased in varying degrees. The average pore size of residual coal reduces from 6.3 nm to 4.9 nm. The oxygen consumption of extracted residual coal in low- temperature oxidation stage is significantly lower than that of raw coal,and CO, CO2, C2H4 and Call6 gas emission re- duced than raw coal to some extend. The soluble organic matter in coal promotes the spontaneous combustion of coal.