Study on Isothermal Adsorption/Desorption Experiment Method of Raw Coal Under the Condition of Surrounding Pressure

In order to deep study the surrounding rock affected to the adsorption features of coal and rock, a experiment method to measure the isothermal adsorpti on/desorption features of raw coal under the surrounding rock pressure was provided and the experiment device could be researched and developed.The method and th e device could be applied to twice isothermal adsorption/desorption repeated experiments with CH4 under the surrounding pressure of 15 MPa for a same dry raw coal sample.The error of the repeatability would be less than 5%，could show a good repeatability of the method and device. The analysis of experiment results with the adso rption theory showed that under the high surrounding pressures, the raw coal sample would have a reversibility of a typical adsorption and desorption and the hysteresi s of the desorption process to CH4.The pore volume variation in coal occurred in the adsorption/desorption process may influence the repeatability tests.