Gas hydrates have garnered significant attention in recent years due to their broad applicability. However, gas hydrate formation typically requires high pressures and low temperatures, which severely limits practical applications. Studies have demonstrated that the addition of gas hydrate thermodynamic promoters (GHTPs) can effectively mitigate these stringent conditions, facilitating hydrate formation. This review offers a concise yet systematic overview of the mechanistic hypotheses and primary classifications of GHTPs, along with a detailed analysis of their promotion efficacy, phase equilibrium behavior, and structural effects. Furthermore, the synergistic effect and hydroxyl effect on hydrate formation were also reviewed. The findings reveal that synergistic combinations of promoters can significantly enhance the thermodynamic stability of gas hydrates. In contrast, hydroxyl-containing compounds generally inhibit hydrate formation, although they exhibit promoting effects in specific systems, governed by the interplay between molecular structure and guest gas characteristics. The review also discusses applications in gas storage and separation, underscoring the importance of optimizing promoter combinations to improve efficiency. Future research should focus on elucidating promotion mechanisms and developing novel promoter systems to advance hydrate-based technologies.
Zhang et al. (Sun,) studied this question.