Abstract
Physical absorption is a potential technology for economic carbon capture due to its low energy consumption, however, the absorption efficiency of current systems must be improved. In this study, novel hybrid absorption/stripping membrane contactors (HASMCs) for physical solvent carbon capture are proposed. The simultaneous absorption and stripping within one module provides instant regeneration of the solvent and results in the enhancement of absorption. HASMCs with parallel-flow and cross-flow configurations and using empty or spacer-filled channels are investigated by rigorous computational fluid dynamics simulation. The internal profiles of transmembrane mass fluxes reveal that cross-flow HASMCs are much more effective than the parallel-flow ones and the modules using spacer-filled channels give better performance than the ones using empty channels. The mass transfer coefficients of HASMCs are much higher than predicted by correlations in the literature.
Highlights
Carbon capture and storage (CCS) has been identified as an essential technology to meet the internationally agreed goal of limiting the temperature increase to 2 ◦ C [1]
Because the chemical solvents must be thermally regenerated with consumption of a significant amount of energy, employing chemical absorption technology in power plants can cause the cost of electricity (COE) to increase by up to 75% [2]
Unlike in CE-hybrid absorption/stripping membrane contactors (HASMCs), comparing BC and Case 4, the increase of mass flux by raising the liquid diffusivity by ten times (Case 4) is limited. This is because the use of spaces has provided substantial enhancement of diffusion effect. For both CE-HASMC and CS-HASMC, the results presented above have demonstrated that the mass fluxes of the first and the second absorption sections as well as that of the first and the second stripping sections can be maintained at about the same level
Summary
Carbon capture and storage (CCS) has been identified as an essential technology to meet the internationally agreed goal of limiting the temperature increase to 2 ◦ C [1]. Fossil fuel power plants will remain a major contributor to carbon dioxide emissions. The state-of-the-art technology for post-combustion CO2 capture (CC) is chemical absorption using amine solvents. Because the chemical solvents must be thermally regenerated with consumption of a significant amount of energy, employing chemical absorption technology in power plants can cause the cost of electricity (COE) to increase by up to 75% [2]. Physical absorption solvents are generated by reducing operation pressure and does not suffer for high energy consumption [3]. Because of the low partial pressure of carbon dioxide in the flue gas, physical absorption technology is not an economical technology for post-combustion carbon capture. The enhancement of physical absorption efficiency for post-combustion flue gas can possibly facilitate the realization of the
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