Hydrate-based carbon dioxide capture from simulated integrated gasification combined cycle gas

The equilibrium hydrate formation conditions for CO₂/H₂ gas mixtures with different CO₂ concentrations in 0.29 mol% TBAB aqueous solution are firstly measured. The results illustrate that the equilibrium hydrate formation pressure increases remarkably with the decrease of CO₂ concentration in the gas mixture. Based on the phase equilibrium data, a three stages hydrate CO₂ separation from integrated gasification combined cycle (IGCC) synthesis gas is investigated. Because the separation efficiency is quite low for the third hydrate separation, a hybrid CO₂ separation process of two hydrate stages in conjunction with one chemical absorption process (absorption with MEA) is proposed and studied. The experimental results show H₂ concentration in the final residual gas released from the three stages hydrate CO₂ separation process was approximately 95.0 mol% while that released from the hybrid CO₂ separation process was approximately 99.4 mol%. Thus, the hybrid process is possible to be a promising technology for the industrial application in the future.