Fundamental Tests on Carbon Dioxide Sequestration Into Coal Seams

Abstract

Carbon dioxide injection into coal seams has become a subject of major interest as a method of carbon dioxide sequestration; sequestration into coal seams is more advantageous than other geo-sequestration because carbon dioxide injected into the coal seam is fixed firmly. Furthermore, when carbon dioxide is injected into coal seams, methane can be recovered as a by-product. This will reduce the cost of sequestration. A fundamental research group carried out various laboratory tests—adsorption tests of carbon dioxide and methane, replacement tests of methane by carbon dioxide, and adsorption tests of coal samples treated by carbon dioxide under supercritical condition. Taiheiyo Coal and Akabira Coal were used in these tests. From the results, it became clear that there is a big difference in adsorption volume of methane between Taiheiyo Coal and Akabira Coal, but there is no difference in carbon dioxide adsorption volume between them at low pressure.