One of the new approaches for capturing carbon dioxide from treated flue gases (post-combustion capture) is based on gas hydrate crystallization. The basis for the separation or capture of the CO₂ is the fact that the carbon dioxide content of gas hydrate crystals is different than that of the flue gas. When a gas mixture of CO₂ and H₂ forms gas hydrates the CO₂ prefers to partition in the hydrate phase. This provides the basis for the separation of CO₂ (pre-combustion capture) from a fuel gas (CO₂/H₂) mixture. The present study illustrates the concept and provides basic thermodynamic and kinetic data for conceptual process design. In addition, hybrid conceptual processes for pre and post-combustion capture based on hydrate formation coupled with membrane separation are presented.