Coal sample gas desorption device and measurement method for simulating variable temperature and variable pressure

Abstract

The invention discloses a coal sample gas desorption device simulating variable temperature and variable pressure, which comprises a gas desorption mechanism, a back pressure mechanism connected to the gas desorption structure, a weighing mechanism connected to the back pressure mechanism, and a gas desorption structure connected to it. The gas charging mechanism and the vacuum pumping mechanism connected with the gas desorption mechanism; the gas desorption mechanism includes two reference tanks and a coal sample tank that are connected to each other, and the reference tank communicates with the gas charging mechanism and the vacuum pumping mechanism at the same time. The sample tank communicates with the back pressure mechanism. The desorption device of this technical solution can accurately set the desorption ambient temperature of coal samples through a constant temperature water bath, and accurately set the ambient pressure of coal sample desorption through a back pressure loading tank, which can be used for gas desorption of coal samples under different ambient temperature and back pressure combinations. According to the gas desorption theory under the condition of variable temperature and variable pressure, the law research can realize the technology of sampling and measuring the gas content of coal seam in the ground full air reverse circulation drilling.

Description

technical field [0001] The invention relates to the technical field of coal seam gas content measurement, in particular to a coal sample gas desorption device and a measurement method for simulating variable temperature and variable pressure. Background technique [0002] Coal seam gas content is one of the important parameters to reflect the occurrence of coal seam gas. It is an important factor for calculating coal seam gas reserves, predicting mine gas emission, designing gas drainage, evaluating the risk of coal and gas outburst, and meeting gas control and drainage standards. in accordance with. According to the difference of gas content measurement process, it is generally divided into direct method and indirect method; according to the difference of measurement space, it is generally divided into surface measurement and underground measurement. At present, the direct method for measuring coal seam gas content in underground coal mines is relatively mature, and the er...

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Problems solved by technology

At present, the direct method for measuring coal seam gas content in underground coal mines is relatively mature, and the error can be controlled within 7%. The direct method is also mostly used for surface measurement, but the compensation for gas loss in the sampling process is not accurate, resulting in an error range of 20% for gas content determination. %~30%

At the same time, the previous sampling methods for ground gas content measurement all used the rope coring method, which was slow in sampling speed and low in success rate. However, the drilling sampling method using full air reverse circulation can make the drilling cuttings at the bottom of the hole > 15m / s However, since the cuttings have undergone changes in temperature and pressure along the process of transportation in the central tube of the double-walled drill pipe, the research on the gas desorption law of coal samples under the condition of variable temperature and pressure is the key to ensure that the ground well The premise of accurate compensation of gas loss in the whole air reverse circulation sampling process

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