[en] Abstract CO2-Enhanced Coal Bed Methane recovery has recently become the subject of a lot of researches and projects all around the world. In order to make accurate prediction of CBM production from coal seams by CO2 injection, it is necessary to have a good knowledge of the transport properties of coal. In order to have access to these properties, it is necessary to study CO2 and CH4 sorption kinetic and diffusion in coal. In this work, CO2 adsorption and desorption rates experiments have been carried out up to 10 MPa by steps on a high bituminous volatile coal sample obtained from the Brzeszcze mine in the Silesian Basin of Poland (RECOPOL Project). The same sample was crushed and sieved in different grain size fractions. A gravimetric apparatus coupled with an electronic pressure regulator has been developed which permits to obtain sorption kinetic data under constant pressure. Influence of grain size of the different coal samples on diffusion has been clearly established. A gravimetric device was used to control in situ the hygrometry of a coal sample. This sample has been used to determine the influence of water on coal matrix diffusivity and sorption kinetics. CO2 adsorption and desorption rates experiments have been carried out up to 10 MPa on one fraction coal sample with different hygrometry levels. A correlation between adsorbed amounts of CO2 and hygrometry levels has been found. Sorption rate experiments have been interpreted with a bidisperse diffusion model to calculate diffusion parameters and see influence of grain size, pressure and hygrometry levels on them
