Continuous seperation of CO2 from a H2 + CO2 gas mixture using clathrate hydrate

CO(2)capture using clathrate hydrates is an environmentally friendly separation technology. When considering operational efficiency, it is desirable to operate the separation process continuously. In this experimental study, the continuous separation of CO2 from a model fuel gas was performed for H-2 + CO2 + H2O and H-2 + CO2 + tetra-n-butylammonium bromide (TBAB) + H2O systems with TBAB mass fractions of w(TBAB) = 0, 0.05, 0.10, and 0.32. Measurements were taken to track the time evolution of compositions of the gas phase and hydrate slurry. After between 37 and 48 h from the start of the experiment, H-2 compositions in the gas phase reached steady state values of 0.87, 0.81, and 0.78 for w(TBAB)W values of 0, 0.05, and 0.10, respectively. For the same conditions, CO2 compositions in the hydrate slurry reached steady state values of 1.00, 0.82, and 0.79, respectively. In carrying out this work we have shown that it is possible to successfully separate CO2 using structure I hydrates and ionic semiclathrate hydrates, on a continuous basis. There is the caveat, however, that for w(TBAB)b = 0.32 a continuous separation process is not possible. The split fraction of CO2 we attained were 0.76, 0.64, and 0.62 for W-TBAB values of 0, 0.05, and 0.10, respectively. The water system (w(TBAB) = 0) exhibited the highest H-2 compositions in the gas phase, highest CO2 compositions in the hydrate slurry, and highest split fraction of CO2. Although short-term operation, specifically 18 h, is possible with w(TBAB) = 0, continuous hydrate formation cannot be implemented. The concentration of captured CO2 for w(TBAB) = 0 was comparable to that obtained from hydrate-based gas separation in multistage processes or chemical absorption.