| Extraction of coal seam gas is one of the mine gas disaster prevention and effective methods, while most of our country’s coal seams permeability is low absorption gas is high,which leads to generally low gas extraction rate.In order to improve coal seam gas extraction rate,we must solve how to increase the permeability of coal seam, and promote coal medium micropore adsorption gas desorption, accelerate the spread of free gas.According to the effect of electromagnetic field on coal seam gas adsorption desorption, this article puts forward the new idea that microwave field action can reduce coal gas adsorption and promote coal gas desorption.Through the theory analysis of microwave field action on coal seam gas adsorption desorption and the experimental study of microwave field action on pore structure and gas adsorption desorption of coal,this article attain the influence law of microwave field action and action time on pore structure and gas adsorption desorption of coal,as well as summary the influence mechanism of microwave field action on gas adsorption desorption characteristics of coal.The main research conclusions are as follows:(1)Microwave field action can decrease Specific surface area and micropore volume of coal.(2)Langmuir constant a of coal sample is reduced after Microwave field action,and with the increase of microwave field action time, Langmuir constant a change a little, first decrease, then slightly increases, then decreases gradually;And the change trend of adsorption constants b is contrary, but consistent with the change trend of the curvature of the isothermal adsorption curve.( 3) The change trend of methane adsorption curve of coal sample is basic consistent after different microwave field action power,and microwave field action change the methane adsorption ability of coal sample,making the methane adsorption quantity of coal sample lower than the without microwave field action.(4)Methane loss curve form of coal sample without microwave field action is identical with the sample of microwave field action.In the situation of methane quantity decrease,methane loss velocity increase a little or keep the same level,which indicates methane loss ability increase fter microwave field action.(5)The influence mechanism of microwave field action on pore structure andgas adsorption and desorption characteristics of coal are mainly electromagnetic radiation effect and damage effect of coal.( 6) As microwave field action time increase, the change process of gas adsorption characteristic of coal as action time changing is divide into three phases. |
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