Experimental Research on Pore Structure and Gas Adsorption Characteristic of Deformed Coal

The pore structure and gas adsorption property of deformed coal with different degrees of metamorphism were tested by low-temperature nitrogen adsorption and isothermal adsorption experiments. The fractal theory and the Langmuir adsorption theory were used to analyze the experimental data. The test results showed that the deformed coal had more het-erogeneous pore structures and open pores, and its speciifc surface area (SSA) and fractal dimension (D) were higher. There is a polynomial relationship between D and speciifc surface area as well as gas adsorption capacity (VL). The gas adsorption capacity of deformed coal is inlfuenced by pore structure, coal rank, deformation and stress together, among which the pore structure is the main inlfuencing factor for the adsorption capacity of deformed coal. The test pressure could affect the ac-curacy of the adsorption constants a and b, so the highest experiment pressure should be greater than the actual pressure of coal seam in order to reduce the deviation of adsorption constants.