High Storage Capacity and Rapid Methane Hydrate Formation Using a Novel Nonfoaming Surfactant

In response to the key challenges faced by methane hydrate (MH) gas storage technology in achieving efficient and green formation, this study designed and synthesized a single-chain surfactant (SCS) that possesses nonfoaming and environmentally friendly properties. Research shows that the comprehensive performance of SCS comprehensively surpasses that of traditional high-efficiency kinetic promoters. SCS exhibits excellent thermal stability and can reduce the interfacial tension and the contact angle to 16.13 mN/m and 31.5°, respectively. Its interfacial regulation ability is significantly superior to that of the traditional promoter SDS. At a low concentration of 0.3 wt %, SCS significantly enhances the kinetic performance of MH formation: the induction time was shortened to 2.5 min, the gas storage capacity reached 171.03 V/V (85.52% of the theoretical value), and the water-to-hydrate conversion rate was 85.42%. Compared with the SDS system, they were increased by 7.63 and 17.11%, respectively, and compared with the pure water system, they were increased by 119.60 times. The study further revealed the mechanism by which SCS promotes MH formation from multiple dimensions, through the synergistic regulation of interfacial tension, micellar solubilization, hydrophobic effect, and wetting behavior. In addition, SCS achieves a foam-free rapid gas release within 55 min in all three cycle experiments, and its dissociation rate is controlled by external heat transfer. Environmental assessment results further validated its good ecological compatibility. During a 72 h culture cycle, the number of E. coli colonies could be increased to 239, and the potential ecological risk was much lower than that of SDS. Therefore, SCS has a great potential in promoting the commercialization of MH technology.