| There are complex geological conditions on coal fields in China, so the deformedcoal (tectonic coal) is distributed widely. Deformed coals have the characteristics ofquick diffuse, easy outburst and poor permeability. So, it has been the focus of the studyand difficulty of the mine gas disaster prevention and CBM exploration. For the existingproblem of the key physical parameters and the physical mechanisms, adsorption-desorption law and its control mechanism of the formation of different types of tectoniccoal, coal samples with primary structure and different deformed structure were selectedfrom Pingdingshan and Jiaozuo mining area. And the history of coal geology andregional tectonic evolutionary history of the study area on the basis of previous researchresults were analyzed. Coal deformation experiments were carried out in hightemperature and high pressure to converse the primary structure coal samples intoexperiment deformed tectonic coals and to explore the key physical parameters and themechanical mechanism of the formation of different types of tectonic coals. Throughhigh temperature and high pressure CH4adsorption-desorption experiments of differentmoisture content of undeformed and deformed coal samples, the CH4adsorption-desorption characteristics and dynamic control mechanisms of deformedcoal were studied under the high temperature and high pressure and three phase media.There are many research results for this studies.（1）The stress-strain conditions of formation of different deformed coals wasascertained preliminarily and its mechanical mechanisms was analyzed by hightemperature and high pressure physical simulation experiment of formation of differentdeformed coals①Simulation of structure physical conditions after coal formation show that coalrock can happen brittle-ductile deformation under the condition of temperature of100~150℃and confining pressure100~200MPa and big dependent variable and lowstrain rate.②In addition to some factors such as temperature, confining pressure conditionsand coal itself, dependent variable and strain rate have important influence on the coalrock deformation properties and the formation features of different defmormed coals. Under the certain conditions of high temperature and high pressure, different dependentvariable and strain rate can form different coal body structure, especially the position isthe closer by failure surface, the damage of coal body structure is the more serious.③The pore structure parameters, pore forms, the pore fractal dimension,microcrystalline structure parameters and adsorption-desorption features onexperimental deformed coals and natural deformed coals were contrasted and analyzedto show that the different dependent variable experimental deformed coals havedifferent adsorption on CH4. So, it can be infered that the coal pore structure is changedbecause of the different variables by high temperature and high pressure condition ofcoal deformation experiments and the adsorption performance of the deformed coals isinfluenced. It shows that the experimental deformed coals can be applied to studyt theadsorption performance of the natural experimental deformed coals. And it provides thecertain possibility to study the adsorption of deformed coals in deep not mining coalseam.（2）The new characteristics on adsorption–desorption of the deformed coals wasfound and its control mechanism was analyzed by the adsorption-desorptionexperiments of deformed coal under the condition of high temperature and highpressure equilibrium moisture.①Under the conditions of high temperature and high pressure equilibrium water,there are the new features on the adsorption–desorption of deformed coal thatLangmuir volume of the VL(ash-free basis) first decreases and then increases, and thendecreases.②The experiment results show that the equilibrium moisture of coal samplesincrease with increasing extent of the damage coal in the conditions of50℃.③Tthe characteristical results of this adsorption–desorption experiments are dueto the combined effects of the unique pore structure of deformed coal and water content.④The adsorption-desorption isotherms of deformed coal are irreversible, and thisirreversible degree increases with increasing extent of the damage of coal. The datas ofshoud not be selected by adsorption datas to carry out desorption experiments on coaland especially deformed coal... |
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