Study on comprehensive utilization technology of low concentration coal bed methane

¹ Chongqing Research Institute of China Coal Technology & Engineering Group Corporation, No.55, Shangqiao village, Shapingba District, Chongqing, China.
² National Key Laboratory of Gas Disaster Detecting Preventing and Emergency Controlling, No.55, Shangqiao village, Shapingba District, Chongqing, China.

^* E-mail: xiaolu8317@126.com

Abstract

Aiming at the problems of low utilization rate and serious environmental pollution caused by low concentration coal bed methane emission in a coal mine, the utilization technology of low concentration coal bed methane was studied by means of field investigation and theoretical calculation, and the technical solution of comprehensive utilization of low concentration coal bed methane combining regenerative oxidation and cryogenic liquefaction was obtained, which realized the “coal and gas are co-mined and shared” and constructed the virtuous cycle development of “use to promote pumping, pumping to promote safety”. The research shows that: the low concentration coal bed methane with concentration of about 5% is converted into high temperature flue gas by regenerative oxidation, and the heat energy is extracted to realize the heating in the mining area; the coal bed methane with concentration of more than 35% is purified and liquefied into LNG product by cryogenic liquefaction, so as to realize long-distance transportation. The technology improves the utilization rate of coal bed methane in the mining area and eliminates the burning of coal for heating. The annual utilization of pure gas is 53.38 million m³, generating economic benefits of 211 million yuan and reducing CO₂ equivalent by 767,000 t. The safety, economic and environmental benefits are remarkable. This technology has practical significance to improve the utilization rate of gas and promote the realization of the goal of zero gas emission.