A Coal Sample Gas Negative Pressure Desorption Experimental System

Abstract

The invention provides a coal sample gas negative pressure desorption experimental system. The system comprises a high-pressure air source module, a coal sample tank, a vacuumizing module, a negative pressure control module and a parameter acquisition, measurement and control module. By the adoption of the negative pressure control module, coal sample gas negative pressure desorption ambient pressure can be formed quickly and controlled stably, so that research of the coal sample negative pressure environment gas desorption rule is achieved. A plurality of gas mass flow meters are combined to measure the desorption gas amount, desorption data is acquired in real time, desorption metering with second as the timing unit is achieved, and personal errors caused by reading through collection process with displacement are avoided. The system is scientific in design, correct in theory, high in metering precision, convenient to popularize and capable of providing a theoretic foundation for reasonably determining the coal bed gas pre-drainage negative pressure value and developing a novel current coal seam gas-bearing capacity determination spot sampling method.

Description

technical field [0001] The invention relates to a coal sample gas negative pressure desorption experimental system, which belongs to the field of coal mine gas disaster prevention and control, and in particular to a system for accurately exploring the desorption law of gas under negative pressure desorption environment pressure and determining a reasonable negative pressure value of coal seam gas drainage experimental system. Background technique [0002] Coal seam gas content and reasonable coal seam gas pre-extraction negative pressure are two basic parameters commonly used in the practice of gas disaster prevention and control engineering. The gas content is often used as the evaluation index of coalbed methane resources, coal mine gas disaster risk and gas drainage effect. The negative pressure of coalbed gas pre-extraction and the gas pre-extraction period are the key parameters to improve the efficiency of gas pre-extraction. Therefore, accurate measurement of coal se...

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Problems solved by technology

[0005] "Experimental Research on Gas Desorption Law of Coal Under Negative Pressure Environment" in "Journal of Henan Polytechnic University (Natural Science Edition)" Volume 30, Issue 6; Chinese patent, patent number is CN203705293U, "Experimental device for gas adsorption and desorption of coal samples under variable pressure conditions "; Chinese patent, publication number is CN103776722A, "Coal seam gas content test method of sampling under negative pressure environment" etc. have entered the exploration of gas desorption law under negative pressure environment, but the method and experimental system proposed have the following problems : ①The accuracy of measurement and control is low, the controllable range is narrow, and the pressure control is unstable; ②The sampling speed of the negative pressure slag discharge sampling process is relatively fast, generally completed within 2 minutes, and the desorption amount measured by the above method is measured in minutes, so it is impossible to obtain The second is the desorption amount of the timing unit, which in turn affects the accuracy of gas loss calculation

[0006] At present, the negative pressure of coal seam gas pre-extraction mostly adopts a negative pressure value of 13kPa, but the differences in coal seam occurrence conditions, coal seam gas permeability, and coal seam gas desorption characteristics will make the effect of gas pre-extraction different when the negative pressure is 13kPa, which will affect mine production. In order to shorten the gas pre-pumping period and improve the gas extraction efficiency, this value should be adjusted according to the actual situation of the mine

[0007] Chinese patent, patent number CN203705293U discloses a "coal sample gas adsorption and desorption experimental device under variable pressure conditions", which uses a vacuum pump to suck the coal sample gas desorption gas in real time, which is to some extent a reproduction of the underground gas extraction form, but It is difficult to accurately determine the negative pressure value of extraction. The reason is that the pressure control uses a vacuum pump, and the negative pressure value is difficult to control stably.

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