Study On Adsorption Characteristics Of High-rank Apropelic Coal In Ankang Area

In this study, the quality characteristics、pore fracture characteristics and CH4isothermal adsorption characteristics of sapropelic coal in Ankang area were studiedthrough series of experiments. The result of this study will provide some basics theroyfor studying pore structure and adsorption characteristics of the sapropelic coal andmarine sapropelic organic.The coal seams in studied area, formed in the early Paleozoic era, experienced along term of geological period and complex tectonic movement. Moreover, becacuseof the multiperiodic hydrothermal intrusive activities, all the coal seams in this earawere formed as tectonic coal. Based on the macerals experiment analysis, regionalcoal was identified as high metamorphic sapanthracite, organic matter were gray orgray-white. The coal seams distributes as slime matrix and do not contain biologicalstructure. Mineral content varies form10%to30%. The inhomogeneous undulatoryphenomenon and particles embedded structure caused by structures can be found inthe coal. However, the results of industrial analysis experimental of regional coal isconsistent with other high-rank anthracite, although the coal in this area is producedat special background.The results of Scanning Electron Microscopy tast show that regional coalcontains lots of tensile fractures, some pressure fractures and rare shear fracture. Thedeveloped pore types from large to small are dissolved pore, inter crystal line pore,porosity, broken pore and directional friction between chip pore, organization pore isvery rare. Organic matters are amlost slime matrixs which have different color depthand arranged as ribbon. Regional coal contains high mineral materials, and theidiomorphic degree of mineral is very high.The results of mercury injection test show that the porosity of coal samplesismedium, the average of porosity is3.85%.The main components are micropores andlarge pores.The average ratio of microporous pore is30.94%, while large pore ratio is24.86%. The cryogenic nitrogen isothermal adsorption test results indicate that poresurface area change from0.453to38.520m²/g, and the average is11.924m²/g. Porevolume change from0.002to0.0547ml/g,and the average is0.0155ml/g. Porevolume and pore surface area are both decreases with the increasing of metamorphicenhancement. According to the analysis of pore volume, specific surface andadsorption/desorption curve types, the pore size in this area is mainly concentrated nearby1.3nm and3.5nm. Pores are in different shapes.Roughly, the one-side closedpore takes the majority, and bottle pore is the second, while parallel plate pore is theleast and slit capillary pore is even less. Moreover, the pore size and pore surfacefractal were also studied, and the affect factors of pore is summarized, finally.The results of CH₄adsorption test show that the Langmuir volume of regioncoal is relatively small, varies from3.58to6.58m³/t and the average is4.86m³/t. Thelangmuir volume is positively correlated with the coal maturity, and negativelycorrelated with equilibrium moisture. Combined with the results of experimentaldataand analysis of the influence factors of CH4adsorption. it is believed that coalmetamorphic degree, porosity, water features, the components of organic matter,mineral and temperature and pressure have certain effect on CH4adsroption for coal.