Deep Eutectic Solvents for Water Vapor Absorption: A New Strategy

Abstract

Gas dehydration plays a critical role in gas refining processes due to the potential problems caused by the presence of water vapor. The inclusion of water vapor can lead to issues such as hydrate formation, pressure drop, and pipeline corrosion. In this research, a deep eutectic solvent (DES) absorbent was employed to absorb water vapor and subsequently, its absorption results were compared with the absorption performance of tri-ethylene glycol (TEG) and lithium chloride as the most common absorbent used in water vapor separation processes. To do so, the influence of several effective parameters, including the inlet air flow rate, different ratios of choline chloride to urea (ChCl:Urea), the weight percentage of liquid water in the absorbent, and the viscosity of DES were investigated. The results revealed that DES is an efficient absorbent for water vapor separation and can separate water vapor from the gas phase far more than TEG and the aqueous solution of lithium chloride. The results also indicated that increasing the inlet air flow rate decreases the absorption recovery due to the reduction of the residence time. Furthermore, it was found that the ratio of 1:2 (ChCl: Urea) results in the highest absorption efficiency.