Experimental study on performance of high purity nitrogen supply system in liquefaction unit of low concentration coalbed methane

Abstract

Aiming at the problems such as low CBM utilization rate caused by low concentration CBM with methane content less than 8% extracted from a small coal mine in Hancheng mining area, Shaanxi Province, and serious environmental pollution caused by coal-fired hot blast stove for heating, the heat storage and oxidation heating technology of ultra-low concentration gas in small coal mine was studied by combining field investigation and heat balance calculation. This technology replaces the coal-fired hot blast stove, realizes “coal and CBM mining and sharing” in the coal mine, and constructs a virtuous cycle development of “promoting drainage by using and promoting safety by drainage”. The research shows that: the scheme improves the utilization rate of CBM in the mining area, cancels the consumption of coal combustion, and can use 2.59 million Nm3 of pure CBM every year, generating 1.95 million yuan of economic benefits. And the emissions reduction of CO2 equivalent is 36000 tons. The benefits of safety, economy and environmental protection are remarkable. This technology is especially suitable for the utilization of ultra-low concentration CBM whose concentration is less than 8%, which has practical significance to improve the CBM utilization rate and promote the realization of the goal of “zero emission”.