Molecular insights into hydrate crystal nuclei stability and quasi-liquid layer in gas-saturated condition
Abstract
The stability of hydrate nuclei is a critical factor in the application of hydrate technology and serves as a key entry point for hydrate prevention and control techniques. However, at present, there is a lack of understanding concerning the stability of gas-saturated hydrate systems. In this work, molecular simulations was utilized to explore hydrate nuclei stability. The results indicate that, compared to water-saturated systems, gas-saturated systems exhibit poorer hydrate stability and require a larger critical nucleus size. Both temperature and the initial size of the nucleus significantly influence the stability of hydrates. Under gas-saturated conditions, a distinct quasi-liquid layer (QLL) forms on hydrate nuclei surface. The presence of QLL effectively delays the intrusion of guest molecules onto the surface of the hydrate nuclei, thereby aiding in the maintenance of their stability. The simulation results provide valuable technical references for the development of hydrate utilization technologies and hydrate prevention and control measures.
水合物核的稳定性是水合物技术应用中的一个关键因素，也是水合物预防与控制技术的重要切入点。然而，目前对于气体饱和水合体系的稳定性仍缺乏深入理解。在本研究中，采用分子模拟方法对水合物核的稳定性进行了探讨。结果表明，与水饱和体系相比，气体饱和体系中的水合物稳定性较差，且需要更大的临界成核尺寸。温度和初始核尺寸均对水合物的稳定性具有显著影响。在气体饱和条件下，水合物核表面会形成一层明显的准液层（QLL）。该准液层有效延缓了客体分子向水合物核表面的侵入，从而有助于维持其稳定性。模拟结果为水合物利用技术以及水合物预防与控制措施的开发提供了有价值的技术参考。
