Closed-loop system for underground gas extraction and utilization and coal seam re-injection permeability improvement and working method

Abstract

The invention discloses a closed-loop system for underground gas extraction and utilization and coal seam re-injection permeability improvement and a working method. The closed-loop system and the working method are suitable for underground abandoned coal mines and coal seams which cannot be mined due to three problems. High-temperature tail gas treated by a gas power plant is injected into a coal seam through a plurality of gas injection drill holes to heat a coal body so as to promote gas analysis, and new hole cracks are generated in the coal body after the coal body in the coal seam is heated so as to provide channels for gas flow; after CO2 in the tail gas enters the coal seam, the gas is replaced, the released gas is extracted and generated by the gas extraction drill holes arranged between the gas injection drill holes at intervals, and closed-loop operation of the whole system is achieved. The tail gas is injected into the coal seam without manual intervention, safety and reliability are achieved, the used tail gas is high in temperature and pressure and does not need an additional heat source, meanwhile, the high-temperature and high-pressure tail gas can greatly improve the coal seam crack and gas output efficiency, and the good utilization effect is achieved for waste mines and coal seams which cannot be exploited.

Description

technical field [0001] The invention relates to a closed-loop system and working method for underground gas drainage and utilization and re-injection into coal seams for anti-permeability enhancement, and is especially suitable for use in abandoned underground coal mines and non-mining coal seams. Background technique [0002] At present, there are still a lot of gas extracted from mines that are not utilized and are directly discharged into the atmosphere, which not only causes waste of resources, but also damages the environment. Methane in mines also poses a threat to the safe production of coal mines. At present, most mines in China have poor air permeability and gas drainage is difficult. Therefore, how to safely and effectively extract high-concentration gas from coal mines and make full use of them is an urgent need to solve key issues. At present, the commonly used gas drainage methods mainly include: hydraulic fracturing, deep hole blasting, hydraulic slitting, and...

AI Technical Summary

Problems solved by technology

[0002] At present, there are still many unused gas extracted from mines and directly discharged into the atmosphere, which not only causes waste of resources, but also damages the environment

Methane in the mine also poses a threat to the safe production of coal mines. At present, most mines in China have poor air permeability and gas drainage is difficult. Therefore, how to safely and effectively extract high-concentration gas from coal mines and make full use of them is an urgent need to solve key issues

At present, the commonly used gas drainage methods mainly include: hydraulic fracturing, deep hole blasting, hydraulic slits, and protection layer mining. However, there are some defects in the application of these technologies. Migrating channels; it is difficult to deliver chemicals in deep hole blasting; the application effect of hydraulic slotting in soft coal seams is poor, and due to the problem of slag discharge, it is not suitable for downward drilling; mining of protective layers is not suitable for mining in a single coal seam

Images