Experimental Research on Influence of Metamorphic Degree on V1 Value of Gas Desorption Characteristics of Coal Samples

To study the numerical relationship between V₁ value of gas desorption velocity and W value of gas content in coal seam in the first minute, three kinds of non-structural coal, anthracite, lean coal and long-flame coal, were used to test the desorption rules under the adsorption equilibrium pressure of 3.0 MPa, 1.7 MPa and 0.5 MPa. Through the linear fitting processing, the linear correlation coefficient R² of V₁ and W is between 0.915 7 and 0.999 4, the results showed that the gas content W could be determined rapidly by V₁. Field verification shows that the absolute error of gas content measurement is -0.63 to 1.25, and the relative error is 1.23% to 8.81%, which meets the engineering requirements.