Continuous separation of CO₂ from H₂ + CO₂ gas mixture utilizing clathrate hydrate for integrated gasification combined cycle power plants

In this study, the CO₂ continuous separation experiments were performed in the system of H₂ + CO₂ + H₂O and H₂ + CO₂ + tetra-n-butylammonium bromide (TBAB) + H₂O for TBAB mass fraction, w_TBAB of 0 (the water system), 0.05, 0.10, 0.32. The time evolutions of compositions in the gas phase and the hydrate slurry were measured. The H₂ compositions in the gas phase for w_TBAB of 0, 0.05, and 0.10 reached steady state at 0.87, 0.81, and 0.78 while the CO₂ compositions in the hydrate slurry were 1.00, 0.82, 0.79, respectively. It is shown that the experiments succeed in continuously separating CO₂ with structure I hydrate and ionic semiclathrate hydrate. On the other hand, the hydrate transportation problem in separation process occurred for w_TBAB = 0.32. For w_TBAB = 0, the highest values of H₂ compositions in the gas phase and CO₂ compositions in hydrate slurry were obtained. The concentration of captured CO₂ for w_TBAB = 0 was comparable to that obtained by multistage process in hydrate-based gas separation or chemical absorption used in the demonstration project of integrated gasification combined cycle.