Liquid carbon dioxide and water vapor anti-reflection coal gas displacement device and method

Abstract

The invention discloses a liquid carbon dioxide and water vapor anti-reflection coal body gas displacement device and method.The device comprises a liquid CO2 anti-reflection mechanism, a high-temperature water vapor mechanism, a reactor, a CO2 collecting mechanism, a water vapor collecting mechanism and an extraction mechanism, the reactor is connected with a CO2 displacement replacement part and a confining pressure loading part, and the CO2 displacement replacement part is connected with a liquid CO2 anti-reflection mechanism; the liquid CO2 anti-reflection mechanism comprises a liquid CO2 tank, a liquid CO2 delivery pump, a liquid CO2 valve and a liquid CO2 box; the high-temperature water vapor mechanism comprises a water tank, a water delivery pump and a vapor generator; the method comprises the following steps: 1, preparing and installing a coal body; 2, loading confining pressure on the peripheral side of the coal body; 3, freezing and permeability increasing of the liquid carbon dioxide on the coal body; 4, melting and permeability increasing of the coal body by the high-temperature water vapor; and 5, CO2 gas displacement and gas extraction are carried out. The liquid CO2 and the high-temperature water vapor are used for forming a cold and hot impact dual permeability increasing mechanism for the coal body, and the coal body gas extraction efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of gas drainage for coal body anti-permeability, in particular to a liquid carbon dioxide and water vapor anti-permeability coal gas displacement device and method. Background technique [0002] Coal accounts for more than 60% of my country's primary energy consumption structure. With the continuous increase of mining depth, coal mine safety production is also facing more severe challenges. As the first of the five major disasters in mines, gas not only affects the safe production of coal mines, but also is an important energy source. Reasonable gas extraction is the basic way to reduce coal mine gas accidents and realize the effective utilization of gas. Due to the low permeability characteristics of most mines in our country, it is necessary to artificially increase the permeability of the coal seam to improve the efficiency of gas drainage. [0003] In recent years, a large number of coal seam anti-perm...

AI Technical Summary

Problems solved by technology

However, the existing research on liquid CO2 fracturing coal is mainly based on coal immersion in liquid CO2, which cannot reflect the actual situation on site (injection); after liquid CO2 freezes, the coal body is in a frozen state, and the pores are blocked by crystalline ice formed by the phase transition of water and ice , the gas drainage cannot be carried out immediately, which delays the gas drainage time and reduces the gas drainage efficiency

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