Hybrid Hydrate-Membrane Post-combustion CO2 Capture: A Conceptual Process Design and Analyses

Efficient capture and storage of carbon dioxide can avoid the global warming crisis. Gas hydrate, as a novel gas in separation technique, has an excellent potential for separation of CO2 from power plants effluent streams. In this study, synergy analysis is performed between hydrate-based and membrane separation techniques to develop a process for postcombustion carbon dioxide capture (hybrid hydrate membrane CO2 capture or HHMCC). The HHMCC process was simulated in four cases to evaluate the effect of hydrate thermodynamic promoters. The proposed processes were studied from techno-economic aspects by performing energy, exergy, and economic analysis. In comparison to the standalone hydrate-based CO2 capture process, combining membrane and hydrate separation techniques reduces the energy consumed per unit weight of captured CO2. Results showed that by applying hydrate promoters, the capital cost decreases, while the energy consumption reduction is not considerable for two of the promoters considered in this study. The energy consumption and cost of the integrated HHMCC process in the presence of tetra-n-butyl ammonium bromide + dodecyl trimethyl ammonium chloride have been estimated to be 1.87 electrical MJ/kg CO2 and 41.75 U.S. $/ton CO2, respectively.