Influence of a Sunflower-Oil-Based Surfactant on Methane Hydrate Formation and CH₄–CO₂ Exchange in a Porous Medium

This study explores the influence of an environmentally friendly surfactant derived from sunflower oil (SFOP1) on the CH4 hydrate formation kinetics and CH4–CO2 replacement processes. Experiments were conducted using varying concentrations of SFOP1 in a porous sandy medium saturated with saline water. The results demonstrate that SFOP1 significantly enhances CH4 hydrate formation efficiency, reducing induction time by 3.74 times and total process duration by 41.72% at the optimal concentration compared to saline water alone. Furthermore, gas consumption increased by 226 mmol, and the hydrate growth kinetic constant rose by a remarkable 103-fold. In the CH4–CO2 replacement process, SFOP1 reduced the overall duration by nearly 4 times, likely due to enhanced CO2 solubility and accelerated hydrate formation through a lowered surface tension. These findings underscore the surfactant’s strong potential to advance CH4 hydrate technologies and CH4–CO2 exchange methods, offering promising applications in sustainable energy and environmental systems.