Thermodynamic and kinetic properties of CO2 hydrates and their applications in CO2 capture and separation

Abstract

The utilization of clathrate hydrates as a highly promising technology for CO2 capture and separation is the focus of this review paper. We present an in-depth exploration of hydrate-based CO2 capture technology, highlighting the use of various additives to enhance the performance of CO2 hydrate formation, as well as the separation and capture of CO2 from gas mixtures containing N2/H2/CH4. By employing thermodynamic promoters, CO2 molecules can efficiently occupy hydrate cages under moderate temperature and pressure conditions, while kinetic promoters improve the kinetic properties of hydrate formation. Key performance indicators such as (normalized) gas uptake, t90, and separation factor are comprehensively discussed and summarized. Moreover, this review introduces additional applications of CO2 hydrates, such as their potential in cold energy storage due to their high heat of formation (Delta Hd) of approximately 500 kJ/kg, surpassing that of ice at 333 kJ/kg. Additionally, we explore the advantages of the CH4-CO2 replacement method, which offers an energy production alternative without the drawbacks of sediment subsidence and ecosystem destruction. Through a comprehensive review, we emphasize the potential of clathrate hydrates as a promising technology for CO2 capture and underscore the importance of further research in this area. Ultimately, CO2 hydrates represent a future direction for mitigating global warming.