Device and method for detecting diffusion coefficient of coal bed gas in coal matrix

Abstract

The invention discloses a method for detecting diffusion coefficient of coal bed gas in coal matrix. The method comprises the following steps: keeping temperature in a sealed and diffused chamber to rated temperature; suspending coal matrix in the sealed and diffused chamber; detecting the air pressure of coal bed gas at each moment in the sealed and diffused chamber; judging whether the air pressure of coal bed gas is rated air pressure; if the air pressure of coal bed gas is lower than the rated air pressure, injecting the coal bed gas into the sealed and diffused chamber by a sealed conduit to cause the air pressure of coal bed gas in the sealed and diffused chamber to reach the rated air pressure; recording the amount of the coal bed gas injected into the sealed and diffused chamber at each moment; and according to the rated temperature, the rated air pressure and the amount of the coal bed gas injected into the sealed and diffused chamber at each moment, calculating the diffusion coefficient of the coal bed gas in the coal matrix. The technical scheme of the invention can detect the diffusion coefficient of the coal bed gas in the coal matrix, which is much closer to the true value compared with the prior art.

Description

technical field [0001] The invention relates to coal bed gas development technology, in particular to a device and method for detecting the diffusion coefficient of coal bed gas in coal matrix. Background technique [0002] Coal bed methane, commonly known as "gas", is an unconventional natural gas associated with coal and stored in coal seams in an adsorbed state, and its main component is methane. Coalbed methane has the following characteristics: First, its calorific value is equivalent to that of natural gas, and it can be mixed with natural gas for mixed use, and it is very clean after burning, and hardly produces any waste gas. It is a good fuel for industry, chemical industry, power generation and residential life ; Second, when the air concentration of coalbed methane reaches 5%-16%, it will explode when it encounters an open flame, which is the root cause of coal mine gas explosion accidents; third, the direct discharge of coalbed methane into the atmosphere has a g...

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Problems solved by technology

[0008] However, in the prior art, this method of using pulverized coal particles as a sample to detect the diffusion coefficient of coalbed methane in the coal matrix, because the sample is powdery, The unique spatial structure of the coal matrix is ​​destroyed, resulting in a large difference between the detection results and the diffusion coefficient of coalbed methane in the real coal matrix

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