Feasibility study on hydrate-based carbon capture driven by solar thermal sorption chiller

Hydrate-based carbon capture is a promising method for carbon dioxide (CO2) capture but consumes a large amount of energy in cooling. This paper investigates the feasibility of CO2 capture from CO2-N2 mixtures driven by solar thermal sorption chillers with the addition of thermodynamic promoter tetra-n-butylammonium bromide (TBAB) and kinetic promoter sodium dodecyl sulphate (SDS). In the gas mixtures of CO2-N2, CO2 molar fraction varied from 32.3 to 76.0 mol%, which covered a wide range of flue gas compositions. CO2 gas uptake, CO2 split fraction and separation factor at temperatures up to 285.45 K and 4.5-MPa feed pressure are studied. The temperature ranges are designed based on the chilled water temperature of an adsorption chiller in Shanghai. The effects of CO2 fraction in the feed gas and TBAB concentrations on the CO2 recovery performance are discussed. In addition, the binary effect of TBAB and SDS is disclosed. The results show that the chilled water temperature from solar thermal driven chillers is sufficiently low to trigger CO2 hydrate formation thermodynamically, and the kinetic performance can be improved by SDS. The combination of TBAB and SDS has the best separation performance under study.