Study on CO2 hydrate formation characteristics with promoters for CO2 capture and cold thermal energy transportation

Abstract

Advancing in a cleaner production and environement, hydrate-based CO2 capture techniques have been spotlighted as a potential future carbon capture technology. The technique allows CO2 to be captured in the form of a hydrate which is capable of storing or transporting CO2 with higher efficiency. Furthermore, CO2 hydrates can be used as energy carriers by capturing the cold thermal energy. Thus, CO2 hydrates can enable effective transportation for both CO2 and cold thermal energy. In this study, the characteristics of CO2 hydrates in the presence of prevalent promoters are studied extensively from various perspectives. CO2 hydrates were produced in an agitating closed absorption chamber under various pressure and promoter concentration conditions with three prevalent promoters: cyclopentane, tetrahydrofuran and tetra-n-butylammonium bromide. Comparison of the promoters under various conditions was carried out by investigating the characteristics during and after hydrate formation. Additionally, the thermal behavior during hydrate formation was observed through the temperature variation to investigate the inside of the chamber during the formation process. Moreover, to understand the CO2 hydrate structures in the presence of the promoters, microscopic and spectroscopic approaches were applied using focused ion beam scanning electron microscopy and X-ray diffraction methods. The CO2 capture performance and characteristics of the CO2 hydrate absorbents were evaluated.