Dissociation experiment of hydrate core sample using thermodynamic inhibitors- part 2

Natural gas hydrate that exists in the sediment is thought to constitute a large methane gas reservoir and is expected to be an energy resource in the future. In order to make recovery of natural gas from hydrates commercially viable, hydrates must be dissociated in-situ. Inhibitor injection method is thought to be one of the effective dissociation method as well as depressurization and thermal stimulation. But there is only limited information about dissociation kinetics in inhibitors, while there exist substantial phase equilibrium data. In our previous study, the dissociation behavior of a hydrate core sample in inhibitor aqueous solution (i.e. methanol aqueous solution) had been investigated using an experimental set-up equipped with core holder. In this study, the experimental set-up was developed to achieve the scale-up experiment and the precise thermal analysis. The length of the core holder was extended to 5 times longer to reproduce the thermal gradient in the core. Using the apparatus, warm pure water was injected through the core samples, which imitate natural gas hydrate sediment under seafloor. Two kinds of experiments were presented in this paper. One was an experiment using the thermal gradient system. And another was that without using it for comparison. From these results the advantage of the temperature gradient system became clear.