Hydrates production with binary CO2/C3H8 gaseous mixtures (90/10, 85/15, 80/20 vol%) in batch and unstirred conditions: The role of propane on the process thermodynamics

Previous studies revealed that the addition of propane enhances the recovery of methane and the storage of carbon dioxide but, at the same time, the enclathration of propane is limited. In order to deepen the CO₂/CH₄ replacement mechanism in the presence of contained concentrations of propane, this research experimentally explores the formation of hydrates into an unstirred reactor with binary CO₂/C₃H₈ mixtures at different concentrations (from 90/10 to 80/20 vol%). The lowest pressures reached within the system, together with the thermodynamic trend of both formation and dissociation processes, allowed to explain the previously mentioned low capture of propane during replacement. The results were then explained in terms of cage occupancy and molecular diameter/cavity diameter ratio.