Tetra- n-butyl ammonium bromide semi-clathrate hydrate process for post-combustion capture of carbon dioxide in the presence of dodecyl trimethyl ammonium chloride

To determine the appropriate operating conditions for separating carbon dioxide from flue gas via the hydrate formation, the effects of the concentrations of dodecyl trimethyl ammonium chloride (DTAC) in 0.29 mol% Tetra- n-butyl ammonium bromide (TBAB) aqueous solution and the initial pressures on the induction time of the hydrate formation and CO 2 separation efficiency are investigated. The experiments are conducted at the DTAC concentration range of 0–0.056 mol%, initial pressures range of 0.66 MPa–2.66 MPa and temperature range of 274.95 K–277.15 K. The results indicate that the initial pressure of 1.66 MPa in conjunction with the concentration of 0.028 mol% DTAC is most favorable for CO 2 separation. At the condition, the induction time of forming the hydrate can be shortened considerably and CO 2 can be purified from 17.0 mol% to 99.4% with the two-stage hydrate separation process. CO 2 split fractions for Stage 1 and Stage 2 are 0.54 and 0.39, respectively, and the separation factors are 9.60 and 62.25, respectively.