Gas Hydrate Formation Process for Capture of Carbon Dioxide from Fuel Gas Mixture

To determine the suitable operating conditions for the hydrate-based CO2 separation process from a fuel gas mixture, the hydrate nucleation and growth kinetics of the simulated fuel gas (39.2 mol % CO2/H-2 gas mixture) in the presence of tetra-n-butyl ammonium bromide (TBAB) are investigated. The experiments were conducted at the TBAB concentration range of 0.14-1.00 mol %, the temperature range of 275.15-282.45 K, the driving force range of 1.00-4.50 MPa, the gas/liquid phase ratio range of 0.86-6.47, and the hydrate growth time of 15-120 min. It is found that the addition of TBAB not only shortens the induction time and accelerates the hydrate growth rate, but also enhances CO2 encaged into the hydrate. However, the number of total moles of gas consumed and the number of moles of CO2 transferred into the hydrate slurry phase decrease with the increase of the TBAB concentration when the TBAB concentration is above 0.29 mol %. The induction time reduces, and the number of moles of gas consumed, the hydrate formation rate, and the number of moles of CO2 encaged into hydrate phase increase with the increase of the driving force. However, when the driving force is more than 2.5 MPa, H-2 prefers to go into the hydrate phase with the increase of the driving force, as compared to CO2. In addition, the temperature has little effect on the hydrate formation process.