Review of fundamental properties of CO2 hydrates and CO2 capture and separation using hydration method

Hydration is an alternative promising method for CO₂ capture and separation from either post-combustion flue gas or pre-combustion fuel gas. The present paper gathers the researches on CO₂ hydrate and the hydrates of gas mixtures of CO₂+N₂/H₂/CH₄, including studies of fundamental thermo-physical properties, molecular structures and hydrate formation equilibrium conditions. Some promoters, i.e. quaternary ammonium salt etc. are usually used in CO₂ hydration process to reduce the hydrate equilibrium pressure and to enhance the hydrate kinetic and stability, hence their promotion effect on CO₂ hydrate and on the hydrates of gas mixture of CO₂+N₂/H₂/CH₄ are reviewed. The paper also summarizes the applications of hydrate technology in CO₂ capture and separation, and the corresponding performance is summarized and the bottlenecks are discussed. It necessitates more works to promote this technology towards industrial application.