Kinetics of Methane Hydrate Formation in the Presence of Silica Nanoparticles and Cetyltrimethylammonium Bromide

Hydrate technology promoted the development of natural gas industry. Nanoparticles showed a broad prospect for hydrate technology because of their excellent mass and heat transfer characteristics. At an experimental temperature of 275.15 K and pressure of 5 MPa, silica nanoparticles and cetyltrimethylammonium bromide (CTAB) were used to investigate the characteristics (pressure drop, gas storage capacity, and formation rate). The experimental results showed that the higher the concentration of silica nanofluid, the shorter the induction time. Among the four silica nanoparticles concentration (0.1, 0.2, 0.3, and 0.5 wt%) tested in this work, the concentration of 0.3 wt% was optimal for the enhancement of CH4 hydrate formation. In the complex system composed of silica nanoparticles and CTAB, the surface of silica nanoparticles was positively charged by hydrolysis. The cationic active groups ionized by surfactants were aggregated to the surface of the particles under the Coulomb force. Methane molecules were gathered to hydrophobic groups by non-polar adsorption, which was more conducive to hydrate formation. Compared to silica nanofluid, the total time for hydrate formation decreased by 66.2 %.