Feasibility study on hydrate-based carbon capture driven by solar thermal sorption chiller
Abstract
Hydrate-based carbon capture is a novel method for carbon capture and storage. However, the formation of carbon dioxide (CO2) gas hydrate leads to a large energy consumption due to the need for cooling. This paper investigates the possibility of using solar thermal sorption chillers to initiate CO2 hydrate formation and CO2 capture from CO2–N2 mixtures by employing thermodynamic promoter tetra-n-butylammonium bromide (TBAB) and kinetic promoter sodium dodecyl sulphate (SDS). In the gas mixtures of CO2 and N2, CO2 molar fraction varied from 32.3 to 76.0 mol%, which covered a wide range of flue gas compositions. CO2 gas uptake, recovery fraction and separation factor at temperatures up to 285.45 K and 4.5-MPa feed pressure are studied. The experimental temperatures are designed according to the chilled water temperature of a solar adsorption chiller. The effects of CO2 fraction in the feed gas and TBAB concentration 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 gas hydrate formation thermodynamically, and the kinetics of formation can be improved by SDS. The combination of TBAB and SDS has the best separation performance under study.