Phase Equilibrium of the Carbon Dioxide and Methane Hydrate in Silica Gel Pores and Thermodynamic Prediction

실리카겔 공극에서의 이산화탄소 및 메탄 하이드레이트 상평형 측정 및 열역학적 예측

Hydrate phase equilibrium for the binary $CO_{2}$+water and $CH_{4}$+water mixtures in silica gel pore of nominal 6, 30, and 100 nm were measured and compared with the cacluated results based on van der Waals and Platteeuw model. At a specific temperature three-phase hydrate-water-vapor (HLV) equilibrium curves for pore hydrates were shifted to the higher-pressure condition depending on pore sizes when compared with those of bulk hydrates. Notably, hydrate phase equilibria for the case of 100 nominal nm pore size were nearly identical with those of bulk hydrates. The activities of water in porous silica gels were modified to account for capillary effect, and the calculation results were generally in good agreement with the experimental data.