Testing method for content of coal seam methane sampled under negative-pressure environment

Abstract

The invention provides a testing method for the content of a coal seam methane sampled under a negative-pressure environment. The testing method comprises the following steps: sampling, namely carrying out in-situ measurement on the methane desorption amount; recording the final in-situ desorption amount V2; determining a methane desorption principle of a coal sample under the negative-pressure environment; carrying out lost methane amount calculation, namely calculating the loss amount V1 according to the measured methane desorption principle of the coal sample under the negative-pressure environment; carrying out residual methane amount laboratory determination, namely heating the coal sample in a sealed state and degassing in vacuum; testing the first-time degassing amount V3; crushing the coal sample by a ball grinding mill and degassing to determine the second-time degassing amount V4; carrying out gas component analysis in the degassing process; and determining the content X of the coal seam methane according to the V1, the V2, the V3 and the V4, and the weight m of the coal sample. The testing method for the content of the coal seam methane sampled under the negative-pressure environment is simple and feasible and particularly has important theoretical values and actual meanings on the desorption amount and the desorption principle of methane under the negative-pressure environment when negative-pressure pumping-out type spot sampling is carried out; the accuracy and the reliability of testing data can be greatly improved and theoretical data are provided for the coal mine safety production.

Description

technical field [0001] The invention belongs to the field of coal mine gas disaster prevention and control, and in particular relates to a method for testing coal seam gas content by sampling in a negative pressure environment. Background technique [0002] my country's coal and gas outburst disasters are serious. Although the "Regulations on the Prevention and Control of Coal and Gas Outbursts" have been implemented since 2009, and strict requirements have been put forward for the mining of coal and gas outburst coal seams, the situation of coal and gas outburst disaster prevention and control is still severe. For example, in 2011 In just 37 days from October 4th to November 10th, 3 major accidents occurred consecutively, resulting in 67 deaths, namely: "10.4" accident in Anping Coal Mine, Qiannan Prefecture, Guizhou Province (14 deaths), Henan Coal Chemical Coking Coal Jiulishan Mine "10.27" accident (18 people died) and the "11.10" accident at Private Village Coal Mine in Q...

AI Technical Summary

Problems solved by technology

[0005] (1) The sampling time is long, resulting in a large amount of gas loss during the sampling process

The gas in the coal sample is completely dissipated, the measured gas desorption rate is relatively small, and the calculated gas loss is relatively small. Moreover, since a large amount of gas has been desorbed, the residual gas amount tested in the laboratory is still relatively small, resulting in a large amount of gas content. The measured value is much smaller than the actual value, which affects the objective evaluation of the gas hazard level and the subsequent selection of reliable prevention and control measures

[0006] (2) It is difficult to achieve real fixed-point sampling. Twist drill pipe sampling is seriously mixed with drill powder, which is far from the requirements of fixed-point sampling, and it is difficult to distinguish the source of coal samples; Fixed-point sampling can be achieved, but limited by the volume of the sampling chamber, the sampling volume is limited; although the core drill bit can be used for fixed-point sampling, and the sampling volume is relatively large, the accuracy of the coal seam gas content test is affected due to the long time for pulling back the drill pipe. is not an ideal fixed-point sampling method

[0007] ⑶. The test method for the gas desorption amount of the coal sample taken out is cumbersome, and the accuracy of the test data is low

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