Methane hydrate nucleation and growth from the bulk phase: Further insights into their mechanisms

Moreover, video monitoring has been performed for most of the hydrate formation/dissociation cycles and pictures were taken at different steps of the hydrate formation. The analysis of the results allowed a better understanding of the hydrate nucleation and growth. Two different mechanisms have been observed according to the initial pressure. At initial pressure around 10 MPa, a thick layer of hydrates was created within a couple seconds at the water-gas interface. This layer hinders the gas diffusion and considerably slows down their growth. At 19.5 MPa, the hydrate formation occurs within a larger volume of the bulk phase, and still close to the water-gas interface. The small hydrate crystals are rather dispersed, allowing the diffusion of gas and enhancing the hydrate growth until the formation of a hard layer at the interface of both phases.