Study on Features Comparison and Mechanism of Methane Adsorbed by Coal Before and After Solvent Extraction

In order to discuss the features difference of methane adsorbed by coal before and after solvent extraction, a tetrahydrofuran solvent was applied to the extraction experiments on four coal samples (long flame coal, gas coal, coking coal and anthracite) and with different metamorphic degree from different areas.A cryoge nic nitrogen adsorption experiment and methane isothermal adsorption experiment was conducted on the raw coal and the coal samples after extraction.The gas chrom atography-mass spectrometry experiment analysis was conducted on the extracts.The results showed that the methane adsorption value of the raw coal under the condi tion of equllibrium moisture would be higher than the coal after extraction and the methane adsorption value of coal after extraction under the dry condition would be hig her than raw coal.The comprehensive analysis showed the different metamorphic degree, porous structure and moisture of the coal would be the major factors to cause the adsorption difference of different rank coal before and after extraction.Thus the paper discussed the aromatic structure and aliphatic compounds in coal before and after solvent extraction comprehensively affected to the coal adsorption gas.