Role of Metallic Packing and Kinetic Promoter in Designing a Hydrate-Based Gas Separation Process

In the present work, kinetics of the hydrate-based gas separation (HBGS) process has been studied employing an unstirred reactor configuration. Gas uptake measurements were carried out for studying hydrate formation kinetics and final water to hydrate conversion using fuel gas mixtures (mixture 1, 40.4% CO2 + 59.6% H-2; mixture 2, 40.9% CO2 + 58.05% H-2 + 1.05% H2S). Silica sand and stainless-steel-structured packing (SSP) were used as contact media in the presence of an anionic surfactant sodium dodecyl sulfate (SDS) as a kinetic promoter. Experiments were conducted with three different concentrations of SDS in water to enhance hydrate formation kinetics. On the basis of induction time and rate of hydrate growth, 1 wt % SDS was determined to be the best concentration for carbon dioxide capture at 7.0 MPa and 273.65 K from the CO2 + H-2 gas mixture. In comparison to silica sand packing, use of SSP was found to improve the final water to hydrate conversion (71.0 +/- 4.1%). The addition of H2S impurity in the fuel gas mixture was also found to enhance the rate of hydrate formation in the presence of SDS at 7.8 MPa and 274.5 K. On the basis of the experimental results and our previous studies on separation efficiency, a continuous HBGS process is proposed to separate CO2 and produce CO2- and H2S-free H-2 stream from a fuel gas mixture.