The Research On Variable Pressure Desorption Characteristics Of Different Coal Samples

Different rank coals at atmospheric pressure and pressure swing adsorption law of CBM shift key scientific problems of occurrence regularity,has a broad application prospect.In the summary of research results at home and abroad on the basis,analysis the different rank coals desorption of existing problems,determines the research goal and the research content,test the parameters of pore structure of different metamorphic degree and damage types of coal,constant,desorption data parameters such as adsorption,the desorption of different rank coals is studied,obtained the following main results:(1)under the condition of normal pressure,coal solution desorption quantity and desorption time meet the Langmuir equation;with the deepening of the degree of metamorphism,in unit time gas desorption quantity increases gradually,desorption rate also increases with the increase of the degree of metamorphism increases;under the conditions of the same equilibrium pressure,desorption of soft coal total amount and initial desorption rate were much higher than those of anthracite,also shows that the soft coal pore connectivity is better than that of anthracite.(2)Strong oxidant treated coal sample desorption rate is greater than the original desorption rate and desorption amount less than total desorption of intact,indicates that strong oxidizing agent can effectively reduce coal reservoir adsorption capacity,promote the desorption of gas.The lower the rank,the more obvious the effect of Strong oxidant on Strong oxidant;soft effect is better than that of hard coal.(3)live agent of coal sample desorption rate greater than moisture content coal desorption rate and desorption amount than the water content of coal sample to small,indicating that change of coal surface containing oxygen functional groups increased,the adsorption capacity decreased,while reducing the surface tension,promote the gas desorption.(4)in the desorption process,desorption curves showed different degrees of volatility,desorption atmospheric pressure often fluctuations in the 20-80 minutes this time in very obvious,pressure swing adsorption under the same pressure desorption also appeared in the relatively large fluctuations,the moisture content coal volatility is most obvious,Hard coal volatility tends to be larger than the soft coal,suggesting that the pore structure of the connectivity and water are the main factors which affect the rate of desorption.