Anomalous diffusion behavior of CO2 in the macromolecular network structure of coal and its significance for CO2 sequestration

This paper gives an analysis of the Thomas and Windle model, which is also proposed to describe anomalous diffusion of CO2 in coal and its relation to matrix swelling. Anomalous (case II, super-) diffusion, which incorporates the swelling of coal matrix by the sorption of CO2, occurs due to coupling of diffusion and relaxation mechanisms. The relaxation process is related to the transition of coal from glassy to a rubbery state, i.e., to swelled...