Role of Surfactants in Promoting Gas Hydrate Formation

TLDR

Gas hydrates are being explored for gas separation, CO₂ capture, transport, methane storage, and desalination, with potential gains from faster nucleation, accelerated growth, and higher water‑to‑hydrate conversion. This review demonstrates that adding surfactants to the gas–water system effectively promotes hydrate formation. Surfactants lower interfacial tension, enhance mass transfer, and alter hydrate morphology, thereby improving gas–water interactions and accelerating nucleation and growth. Literature analysis shows that the accelerated kinetics are not solely due to micelle formation, indicating other mechanisms such as surface‑tension reduction are responsible.

Abstract

Gas hydrates have been proposed as a potential technology for a number of applications, such as separation of gas mixtures, CO2 capture, transportation, and sequestration, methane storage and transport, and seawater desalination. Most of these applications will benefit from reduced induction time of hydrate nucleation, enhanced hydrate growth rate, and maximum water-to-hydrate conversion. The addition of surfactants to the gas–water system serves this purpose in a very effective manner. This review focuses on different surfactants that were utilized for gas hydrate formation studies; insights have been provided on the possible mechanisms of action through which these surfactants affect hydrate formation kinetics. A thorough analysis of the existing literature on surfactants suggests that enhanced rate of hydrate nucleation and growth kinetics may not be directly linked to micelle formation. Conversely, reduced surface tension in the presence of surfactants not only enhances the mass transfer but also changes the morphology of hydrate formation, which in turn enhances gas–water interactions for faster hydrate growth rate.