An Experimental Study On The Mechanism Of Adsorption And Desorption Of CBM On Low-rank Coal

Over a long period of time, the exploration and development of CBM were mostly focused on the coal district of the medium-high rank of coal. However, the exploration and development of low-rank coal and the corresponding research still were the blank in our country. The low-rank coal usually is refers to the lignite, the flame coal, it's dip angle of maximum reflectance is smaller than 0.65%, this kind of coal physicochemical properties and the pore structure have the big difference with the medium-high rank coal. So it is inevitable to cause the CBM of low-rank coal's specificity in its adsorption-desorption characteristics.This article studies mainly take the adsorption-desorption isotherm experiment as a method, carries on the adsorption-desorption experimental study to the CBM of low-rank coal. Through the laboratory massive determination data, unifies to the low-rank coal basic structure characteristic and the adsorption characteristic fundamental research, the characteristics of reserve gas on low-rank coal has been carried on the detailed analysis, and the features of desorption of methane on low-rank coal is also analyzed. The research indicated that:Low-rank coal hole structure characteristic take macropore and mesopore primarily, ascopore and micropore as auxiliary, this kind of unique feature causes the low-rank coal to have the high permeability, the low adsorbability characteristic; The adsorption ability of methane on low-rank coal is lower than the medium-high rank coal, but the low-rank coal has the good free gas accumulation ability; The low-rank coal displays the non-invertibility to the adsorption-desorption process of methane on low-rank coal. In order to assure the accuracy of experimental data, the experimental error has been carried on the detailed analysis in this paper.At last, according to the low-rank coal gas storage characteristic and the desorption...