Technical Session 6:

Title:           Basic Research of Enhanced Coalbed Methane Recovery by Injecting Air
Authors:      Noritaka Shimatani, Yuichi Sugai, Kyuro Sasaki
Abstract:   CO2 is injected into coal seam for enhancing coalbed methane recovery. CO2 however causes coal swelling and permeability reduction of coal seam, which causes reduction of injection capability. In addition, several facilities should be constructed to separate, transport and store CO2. This study suggests a novel technique enhancing coalbed methane recovery injecting air into coal seam. CO2 can be generated in-situ due to coal oxidation. Desorption of coalbed methane may be also stimulated by heat which may be generated by coal oxidation. Air can be obtained easier than CO2, therefore, our technique has economic efficiency. We estimated the possibility of air injection by carrying out experiments of coal oxidation under low temperature conditions and conducted gas adsorption studies. Chinese lignite whose moisture content was 20.1% was used in this study. The powder of the lignite was filled in a pressure vessel whose internal volume was 75 mL. To evaluate the oxidation of coal, gases such as Air, O2 and N2 were injected into the packed bed of the coal power. The pressure vessel was put in a thermostatic chamber whose internal temperature was 40ºC. The gas was injected into the packed bed of the coal powder at a predetermined pressure. From the oxidation studies, the oxidation and potential of Air- ECBM were confirmed. In gas adsorption studies, CO2, CH4 and N2 were used to single gas and dual gas experiment conditions. From these studies, differences of gas adsorption were confirmed between ideal condition and real condition. The Langmuir volume and pressure were also measured and numerical simulations of CO2-ECBM and N2-ECBM were conducted.

Keywords: Enhanced coalbed methane recovery, Air injection, Adsorption, Carbon dioxide, Simulation
Pages:        185-188

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