(112d) Progress On the Hydrate Based Gas Separation (HBGS) Process for Carbon Dioxide Capture

Hydrate based gas separation (HBGS) process is one of the promising new approaches for CO₂ separation from fuel gas through gas hydrate formation. The basis for separation is the selective partition of CO₂ component of a fuel gas mixture between the hydrate phase and the gaseous phase upon hydrate formation. The advantage of HBGS process are energy efficiency and clean technology, and it can simultaneously capture H₂S and other sulfur compounds. In this study, 2.5 mol% propane was added to the fuel gas mixture as additive to decrease the operating pressure in a novel fixed bed reactor employing silica sand and silica gel as media. Kinetic experiments were carried out at three different pressures (4.5, 5.5 and 6.0 MPa respectively) and at 274.15 K. Water conversion of up to 38% was achieved in silica sand bed where as in silica gel bed water conversion of 13% was achieved. Our results suggest that inter-particle pore space enhances the hydrate formation compared to the internal pore space in the particle. Hence, we replaced silica sand with inter connected HydraPor medium in which the inter-particle pore space is the dominant contributor to bed porosity. Water conversion of up to 65% was achieved at 6.0 MPa and 274.15 K. Our results on HydraPor media validates that the inter-particle pore space is the reason for enhanced kinetics and a fixed bed set up can be employed for potential scale up of the HBGS process. Our study also suggests that presence of propane not only decreases the operating pressure, it also enhances the kinetics of hydrate formation.