Synergistic Promotion of Methane Hydrate Formation by 1,3-Dioxolane and Sodium Lignosulfonate: A Study of Kinetic Characteristics

Hydrate-based technology is an innovative and efficient way to store and transport methane (CH4), offering advantages such as high efficiency, low energy cost, and safe utilization. This study focuses on the effects of two promoters, i.e., 1,3-dioxolane (1,3-DIOX) with low toxicity and the biodegradable sodium lignosulfonate (SL-Na), on the formation of CH4 hydrates. The results indicate that at 3.0 MPa, the system of 5 mol % 1,3-DIOX + 0.5 wt % SL-Na leads to the maximum increase in nucleation temperature. Besides, 1,3-DIOX significantly increases the nucleation temperature, while high concentrations of SL-Na decrease it. Additionally, 1,3-DIOX can accelerate the formation of CH4 hydrates, while the SL-Na systems require longer growth times and exhibit higher gas consumption. In the study of the compound system, the 5 mol % 1,3-DIOX+0.25 wt % SL-Na compound system has the highest nucleation temperature of 283.65K, the shortest induction time of 1.1 min, and the highest gas consumption rate, which is about 27.82 times that of the pure water system. The 1 mol % 1,3-DIOX+0.5 wt % SL-Na compound system has the longest growth time of 652.6 min and the highest gas storage capacity, which is about 7.41 times that of the pure water system. Although the 1,3-DIOX + SL-Na compound systems generally take longer to nucleate, they accelerate the gas consumption rates overall. In conclusion, combining 1,3-DIOX and SL-Na can improve the kinetic formation of CH4 hydrate, providing valuable methods for optimizing CH4 storage efficiency.