溶剂抽提损伤致裂煤体实验研究

致密煤层中瓦斯的运移和抽排与煤体的致裂损伤有着密切的联系,溶剂抽提致裂煤体、产生裂隙会有助于低渗透性煤层瓦斯的运移.本文对块体煤进行了不同种类溶剂的抽提损伤实验,测定了抽提损伤后煤体的孔隙率变化.溶剂种类对煤体的致裂损伤作用效果显著不同,N-甲基-2-吡咯烷酮(NMP)抽提后的煤体形成了许多裂隙;二硫化碳和NMP混合溶剂体系对煤体的抽提存在协同作用,其对煤体的抽提损伤效应大于单种溶剂;NMP和NMP与二硫化碳混合溶剂抽提后煤体的孔隙率约是原煤体孔隙率的4倍和5倍,煤体的孔隙率增大十分明显;抽提物及抽提残煤体的红外光谱和热重分析表征结果表明,与原煤相比,抽提残煤中的脂肪烃类物质明显减少.

Experimental Research on Solvent Extraction Damage and Cracks Formation of Coal Body

Gas migration and discharge in compact coal seams are strongly related to coal body damage and cracks formation.Coal body cracks formation conduces to gas migration in low permeability coal bed.The coal body extraction damage experiments under different kinds of solvents were done,the porosity changes of coal body residues extracted by different solvents were determined.The effects of different kinds of solvents on coal body damages were considerably different.A large amount of cracks were formed after N-methyl-2-pyrrole(NMP)extraction.Furthermore,the better effects on coal body damages and the visible coal body swelling were achieved by applying the mixture of NMP and carbon bisulphide.This solvents combination showed a good synergistic effect other than single solvent.The porosity of coal residues extracted by NMP and NMP with carbon bisulphide mixed solvent was approximately 4 times and 5 times of the raw coal body,respectively.The coal body porosity increased dramatically by solvent extraction.The analysis of the extract and extracted residue by means of FTIR and TG techniques indicated that the aliphatics in extracted coal residue decreased dramatically after solvent extraction compared with raw coal body.