The feasibility of H2S removal from gas mixture using hydrate formation was examined theoretically as well as experimentally. The hydrate formation conditions for a three-component gas mixture of CO2, He and a small amount of H2S (30%-CO2, 70%-He and 50 ppm-H2S) were determined using a high-pressure equilibrium cell by a visual observation method. It was found that He only plays a role in gas diluents, whereas H2S decreases the dissociation pressures of gas hydrate slightly. A fugacity-based model was used to demonstrate the characteristics of H2S removal by hydrate formation. The advantage of a gas hydration process for H2S removal was described in terms of removal efficiency. Upon calculation with our model, the removal efficiency by hydrate formation ranges from 8 to 11 and is approximately 3 or 4 times greater than that by liquid water scrubbing.
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