Gaoming Wei , Li Ma , Xin Yi , Hu Wen , Shangming Liu , Ruizhi Guo
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引用次数: 0
Abstract
This study focuses on the efficiency of liquid CO2 (LCO2) displacing CH4 in the coal under optimal Ti and Pi. The objective is to study the influence on the efficiency of LCO2 injection to displace CH4 under the different temperature (Ti) and pressure (Pi). Thereafter, an in-situ test is conducted on LCO2 injecting to enhance coalbed methane (LCO2-ECBM) in a high-gas coalbed. Results showed that low temperature inhibited the movement activity of CO2/CH4 in coal, a significant delayed effect is exhibited during CO2 displacing CH4, and the maximum displacement efficiency (ηmax) is only 56.02 %. The competitive-adsorption effect of CO2/CH4 intensified, and ηmax increased to 84.13 % as Ti gradually increased. The CH4 desorption rate and migration dynamics in the coal intensified as Pi increased, resulting in a significant increase in efficiency, and ηmax reached 92.87 %. At 30 °C, where CH4 is present in the coal, an appropriate increase in Pi caused the maximum replacement ratio to decrease from 1.60:1 to 0.40:1, indicating a higher efficiency. An In-situ test of LCO2-ECBM showed that the concentration and flow rate of methane increased by nearly three times, and the CBM extraction time and borehole layout number have been shortened by one-third and half, respectively.
期刊介绍:
Case Studies in Thermal Engineering provides a forum for the rapid publication of short, structured Case Studies in Thermal Engineering and related Short Communications. It provides an essential compendium of case studies for researchers and practitioners in the field of thermal engineering and others who are interested in aspects of thermal engineering cases that could affect other engineering processes. The journal not only publishes new and novel case studies, but also provides a forum for the publication of high quality descriptions of classic thermal engineering problems. The scope of the journal includes case studies of thermal engineering problems in components, devices and systems using existing experimental and numerical techniques in the areas of mechanical, aerospace, chemical, medical, thermal management for electronics, heat exchangers, regeneration, solar thermal energy, thermal storage, building energy conservation, and power generation. Case studies of thermal problems in other areas will also be considered.