Decomposition of CO₂, CH₄ and CO₂-CH₄ Mixed Gas Hydrates

Abstract

To evaluate the possibility of CH₄ exploitation in linkage with CO₂ isolation, the decomposition rates of CO₂, CH₄ and CO₂-CH₄ mixed gas hydrates were obtained under isothermal isobaric conditions. The decomposition rates of CO₂ and CH₄ pure gas hydrates are proportional to the total amount of gas hydrate and the fugacity difference from the equilibrium state under the conditions of three-phase coexistence. The rate constant of CO₂ hydrate decomposition is larger by one order than that of CH₄ hydrate. In the CO₂-CH₄ mixed hydrate decomposition, CH₄ composition in the generated gas is substantially larger than the value calculated from the pure hydrate decomposition rate while CO₂ remains selectively in the mixed gas hydrate.