Rapid formation of methane hydrate in environment-friendly leucine-based complex systems

Given the growing demand for natural gas (NG) in energy supply systems worldwide, solidified natural gas (SNG) is viewed as a potential NG storage and transportation method owing to its numerous advantages. However, using significant amounts of sodium dodecyl sulfate (SDS) to improve its slow formation kinetics has a negative influence on the environment, and severe foaming hinders the system's recovery. To overcome the associated issues, the main promoter has been chosen to be the ecologically safe and non-foaming L-leucine, with low concentrations of SDS and NaCl, as well as glass beads of various particle sizes, added to achieve synergistic effects. The hydrophobic micro-regions created by the leucine molecules, as well as the porous hydrate characteristics, considerably enhanced hydrate formation in the leucine-based complex system. At the effective promotion concentration, the SDS dosage is reduced by 60-90%. Owing to their strong promotion effect and non-foaming feature, yielding almost non-toxic properties, the LS1 and LN4 systems may be employed commercially. With a target of advancing SNG technology, this study serves as a reference for future developments of SNG technology based on the idea of environmental friendliness.