Experimental study on improving coal permeability with supercritical CO2 and low-carbon alcohol solution

The high-gas and low-permeability are the common problems of China coal mine, which restrain the mining of coal resources safely and efficiently. To solve the low permeability of coal-seam, the variation of permeability was studied experimentally with coal effected by supercritical CO2 and low-carbon alcohol solution (including methanol solution, ethanol solution and isopropyl alcohol solution). The results show the permeability of coal after injecting supercritical CO2 is nearly one order of magnitude over former testing. This is principally resulted from that supercritical CO2 will extract some organic matters of coal substrates. Meanwhile, the permeability of sample effected by low-carbon alcohol solution is apparently higher than former experiment without solution. Moreover, the bigger volume concentration to certain low carbon alcohol solution, the greater the permeability will increase. As to the three different low-carbon alcohol solution, the isopropyl alcohol solution has a biggest influence on improving coal permeability, whereas the methanol solution has a smallest one. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of China Academy of Safety Science and Technology, China University of Mining and Technology(Beijing), McGill University and University of Wollongong.