WPŁYW PRESORPCJI METANU NA ZMIANY WYMIARÓW ZEWNĘTRZNYCH WĘGLA KAMIENNEGO PODCZAS SORPCJI DITLENKU WĘGLA

Abstract

THE EFFECTS OF METHANE PRESORPTION ON THE VARIATIONS OF EXTERNAL DIAMETERS OF HARD COALS DURING THE SORPTION OF CARBON DIOXIDEAbstract. Experiments were performed to investigate the hard coal behaviour while accumulating mine gases and the changes in its external dimensions that accompany this process. Sorption of mine gases brings about an increase of external dimensions of coal, and their desorption is accompanied by coal contraction. The results show that coal expansion is more pronounced in the direction perpendicular (ε˪) to the bedding than parallel to it (ε//). The equilibrium condition both in sorption and expansion processes can be reached more quickly in the coal-CO2 than for coal-CO4 systems. In spite of the fact that coals tend to sorb CO2 much more effectively than CH4, their deformation ability due to sorption is three times greater during sorption of carbon dioxide than for methane. The tests reveal that injection of carbon dioxide to the coalbed containing methane may lead to increased stresses in the rock strata as the coal will not be able to expand any further and this will cause changes of the seam permeability.