Kinetics study of methane hydrate formation in active coal slurry

The key to enabling the large-scale application of hydrate-based technology lies in enhancing the reaction rate and gas storage density. In this study, an active coal slurry was prepared by vigorously stirring a mixture of SDS solution and micron-sized coal powder. The kinetics and gas storage performance of methane hydrates were investigated in active coal slurries with coal concentrations ranging from 5.0 to 35.0 wt%, under conditions of 8.0 MPa and 274.15 K. The results indicated that the coal powder used has a rich microporous structure and a high specific surface area, which can provide abundant nucleation sites for the formation of hydrate. At a coal powder concentration of 5.0 wt%, the gas storage performance was optimal, achieving a maximum gas storage rate of 9.3 cm³·cm^–3·min^–1, a maximum gas storage capacity of 166.9 cm³·cm^–3, and a time to reach 90% of the maximum capacity （t₉₀） of 9.3 min. Further analysis of energy density indicates that coal-based hydrates consistently exhibit higher energy density than traditional coal-water mixtures at identical coal powder concentrations. Among these, the binary fuel prepared from active coal slurry at a concentration of 30.0 wt% demonstrates the optimal energy density performance.