Liquid Water-Hydrate-Vapor Equilibrium for Methane + Ethane Gas Mixtures: Application of Gas Hydrates for Separation

In this communication, liquid water-hydrate-vapor (L_w-H-V) phase diagrams for methane + ethane gas mixtures are predicted using van der Waals-Platteeuw solid solution theory. Experimental measurements were conducted and the results exhibited that methane was effectively separated from ethane by hydrate formation. To perform the experiments, methane + ethane gas mixtures were contacted to excess water at appropriate conditions. Once the hydrate phase was produced, the compositions in the gas and hydrate phases were measured meticulously and reported. Presented in this work, methane was enriched in the residual vapor phase, while ethane was enriched in the hydrate phase. The performed experiments justify the use of gas hydrate as a feasible method for separation. The model predictions of the pressure-composition diagram are also in good agreement with experimental results. (Figure Presented).