One of the new approaches for capturing carbon dioxide from treated flue gases (post-combustion capture) is based on gas hydrate crystallization. The carbon dioxide content of the gas hydrate crystals Is different than that of the flue gas. This provides the basis for the separation or capture of the CO 2. Moreover, when a gas mixture of CO2 and H2 forms gas hydrates the CO2 which forms hydrate at tower pressure prefers to partition in the hydrate phase. This provides the basa for the separation of CO2 (precombustion capture). The present study illustrates the concept and provides basic thermodynamic and kinetic data supporting process development. © 2006 IEEE.