Magnetic nanopromoter enables excellent kinetic promotion and cycling performance in methane hydrate formation

Among several promising applications of gas hydrate-based technologies, storage and transportation of gases (H2, CH4, CO2, etc.) in the form of hydrate has aroused extensive concern. Currently, developing an effective and recyclable promoter holds the key to achieving the industrial application of hydrates. Herein, we proposed sulfonated magnetic polymer nanoparticles as the promoter for methane hydrate formation, which are synthesized by sulfonating the magnetic Fe3O4 particle in the soap-free emulsion system. Then the performance of the promoter was evaluated with regard to induction time, reaction time, and storage capacity at different concentrations. Hydrate formation results showed that when the mass concentration was 20 g/L, the storage capacity can reach up to 137.0 ± 2.8 v/v with the reaction time of 28 min while the induction time was only with the range of 44.1 ± 13.52 min. Further, the hydrate structure (sI) and dynamic occupancy change of 51262 and 512 cage were studied by the in-situ Raman at micro level and meanwhile the macroscopic morphology observation was also conducted. In addition to the high performance described above, the promoter also exhibited high-performance reliability in 15 cycles of hydrate formation experiments. This indicates that the promoter has great promise on economic benefit, environmental friendliness and recyclability for application in the methane hydrate-based technology.