Flue gas injection for CO_2 storage and enhanced coalbed methane recovery: Mixed gas sorption and swelling characteristics of coals

摘要

The impact of coal pore structure on adsorption-induced matrix swelling of three coals of different ranks was investigated experimentally. The swelling strain measurements for the selected samples of the two higher rank coals suggested that variation in the sample pore size distribution, particularly the microporosity, has a larger impact on matrix swelling induced by adsorption of CO_2 than by adsorption of less adsorbing gases. The swelling behaviour recorded for the low rank coal may be explained by the level of microporosity or lack of it. From flue gas ECBM point of view, the swelling strain data tentatively suggests that the low rank coal would experience less swelling, compared to the higher rank coals.