Analysis of Hydrate Formation Kinetics and Wall-Climbing Growth Regulation Using Biofriendly Promoters: Synergistic Effects of Erioglaucine Disodium Salt and Sugar Alcohol

The high toxicity, excessive foaming, and wall-climbing behavior of traditional promoters limit their large-scale use in hydrate-based gas storage and separation. Environmentally friendly and efficient hydrate management strategies are needed. We used a sapphire cell for comparative analysis of kinetic dynamics and wall-climbing morphology during hydrate formation under sugar alcohol (SA) and erioglaucine disodium salt (EDS). Microscopic analyses explored the mechanisms of EDS and SA on hydrate formation, with comparisons to amino acids. This is the first report on the synergistic effects of SA and EDS, both of which exhibit excellent biocompatibility and degradability, not only in significantly enhancing hydrate formation but also in regulating hydrate wall-climbing behavior. Three distinct modes of hydrate wall-climbing were observed at varying concentrations of EDS and SA. At a concentration of 4 ppm EDS + SA, hydrates exhibited an “antenna growth” mode, characterized by delayed promotion and a significantly prolonged induction time compared to the film formation time. In contrast, 200 ppm EDS + SA demonstrated a strong synergistic effect, drastically reducing both film formation and induction times. Microscopic characterizations revealed that while EDS + SA enhanced the selectivity of the hydrate for CO2, it did not alter the hydrate cage structure. Optical microscopy results further demonstrate that EDS + SA can inhibit the capillary growth of hydrates and alter their crystal morphology. These findings suggest a mechanism in which a hydrophobic skeletal network promotes hydrate formation and regulates wall-climbing behavior. The EDS + SA combination holds promise for large-scale hydrate applications, offering efficient promotion and wall-climbing control.