Study On The Controlling Factors Of Gas Hydrate Formation From Ice Powders

Natural gas hydrate as a main strategic energy resource in the future has attracted tremendous attention at home and aboard. Because it’s not easy and economical to get the natural hydrate sample from the marine hydrate sediments for study, synthesizing methane gas hydrate in laboratory by simulating environment conditions have become a necessary means. In the processes of the artificial hydrate synthesis, the formation mechanism and promoting formation factors has always been the focus of research. In this study, the effects of controlling factors such as initial temperature and pressure, particle size of ice powders and surfactant on the methane hydrate formation from ice powders were studied through experiments with the aid of gas consumption during the formation reaction (pVT method). And then, the optimal parameters control and reaction mechanism were explored. Furthermore, the secondary pressurization and superheated ice were studied and analyzed to improve the saturation of methane hydrate. This work provides solutions to generate high saturation of methane hydrate in laboratory.In this paper, the results of studying the effects of controlling factors on methane hydrate formation from ice powders show that a certain degree of low temperature is helpful to methane hydrate formation under the same initial pressure. When the temperature of the system is below the melting point of ice, but close to it, the different initial pressures leaded to different rate of methane hydrate formation. And the higher the initial pressure is, the more obvious the effect of promoting methane hydrates formation becomes. While at the lower temperature far away below the melting point of ice, the pressure difference has a minor role on it. The temperature has more strong control action than pressure. Simultaneously, it was found that the pressurization rate also has effect on methane hydrate formation. And the lower rate of pressurization has beneficially effect on it. The smaller grain size of the ice powders are, the greater the special surface area is. That increases the contact area of methane gas and ice powders, which promotes methane hydrate formation. In addition, adding surfactant SDS to the deionized water when making ice powders can effectively promote methane hydrate formation and shorten the time of formation reaction. The study of methane hydrate formation from ice powders with100,300,500ppm SDS shows that the promoting effect of300ppm SDS is greatest. Finally, a series of experiments were conducted to study the effect of secondary pressurization and superheated ice on methane hydrate saturation. The results indicate that secondary pressurization and superheated ice can improve the methane hydrate saturation, especially the superheated ice is more effective.