Hydrate-based pre-combustion carbon dioxide capture process in the system with tetra-n-butyl ammonium bromide solution in the presence of cyclopentane

Effects of 0.29mol% tetra-n-butyl ammonium bromide (TBAB) solution in conjunction with cyclopentane (CP) on the hydrate-based pre-combustion CO2 capture are investigated by the measurements of the gas uptakes, CO2 separation efficiencies and induction time of the hydrate formation at the different temperature–pressure conditions. The results show that the volume of the TBAB has an effect on the CO2 separation and the induction time, and the addition of the CP into the TBAB solution remarkably enhances the CO2 separation and shortens the induction time. The system with the CP/TBAB solution volume ratio of 5vol% and TBAB solution/reactor effective volume ratio of 0.54 is optimum to obtain the largest gas uptake and the highest CO2 separation efficiency at 274.65K and 4.0MPa. Compared to the results with tetrahydrofuran (THF) as an additive [1], the gas uptake is enhanced by at least 2 times and the induction time is shortened at least 10 times at the similar temperature–pressure condition. In addition, the CO2 concentration in the decomposed gas from the hydrate slurry phase reaches approximately 93mol% after the first-stage separation at 274.65K and 2.5MPa. The gas uptakes of more than 80mol% are obtained after 400s at the temperature range of 274.65–277.65K and the pressure range of 2.5–4.5MPa.