(Special session/Open call for public) Recent trends in the development and utilization of coal and other energy resources

[2K0101-11-10] Study on gas adsorption of coal for enhanced coal bed methane recovery

○Theodora Noely Tambaria¹, Yuichi Sugai¹ (1. Kyushu University)

Chairman:Akihiro HAMANAKA (Kyushu University)

Keywords:ECBM, gas adsorption, coal

Gas injection for enhanced coal bed methane (ECBM) considered as effective method due to coal absorb gas emissions storage and can release methane contained in coal for use. This research is to provide state-of-the-art research developments in gas adsorption for enhanced coal bed methane. The presence of moisture and ash yield will block gas adsorption into coal. Coal composed with higher percentage of vitrinite and liptinite macerals will react to CO₂ adsorption. The coalification process makes changes in the coal pores and due to that different rank of coal shows different adsorption reaction. Bituminous coal rank has higher potential for ECBM due to thermogenic gas and variative pore size. Pure gas and mixed gas commonly used for ECBM. CO₂ was the most effective gas for enhanced coal bed methane and CO₂ and N₂ mixed gas cannot be used as carbon capture and storage (CCS) but it is very effective to increasing coal permeability and lead to increases the methane production. Low temperature N₂ adsorption (LTNA) can detect macropore and mesopore meanwhile CO₂ adsorption can detect micropore on coal. Calculation of adsorption on coal was carried out experimentally and modeling. Experimentally, it is generally done by gravimetric and volumetric methods. The gravimetric method based on microbalance can detect changes due to adsorption of weight, but this method is very sensitive and cannot be tested in large quantities. Volumetric method test the adsorption in large quantities and using various pressure changes, but difficult to determine the amount of gas adsorbed. The calculation of adsorption using modeling can be done by several methods, but the modeling method ignores the physical mechanisms in coalbeds. The effect of gas adsorption is highly dependent on temperature and pressure where the maximum swelling by coal adsorption for CO₂ injection.