Study on characteristics of adsorption / desorption of medium and high rank tectonic deformation coals in Henan Province

The methane adsorption 1 desorption capacity and characteristics were related to the degree of coal metamorphism and deformation structure. The isotherm al adsorption 1 desorption experiment of five medium and high rank tectonic deformation coals samples at typical mining fields in Henan Province were conducted,the result s showed that the methane adsorption capacity of weak brttle tectonic deformation coals of medium and high rank increased with increasing along with the degree of coal metamorphism.As the pressure rised,the increment of methane absorption quantity decreased gradually and tended to zero,while the increment of methane absorption qua ntity increased with the increment of the degree of coal metamorphism. The methane desorption quantity during unit pressure within the period increased with power functi on with the pressure decreasing. With the degree of coal metamorphism increased,the methane desorption quantity during unit pressure within the period increased.The me thane desorption quantity curve was monotone increasing logarithmic function with pressure decreased to different tectonic deformation coals ,the methane desorption quan tity was improved with the increasing tectonic deformation degree.