Study On Experiment And Dynamical Model Of Formation Of Methane Hydrate From Ice Powder

Because of its potential resource, methane hydrate has become the most popular research issue in the world’s energy research. The deep ocean floor and permafrost areas are the main naturally storage area of methane hydrates. And the main formation conditions are low-temperature and high-pressure environment. The main study of generate kinetic is above freezing at present, and it is not suitable to permafrost regions which is below freezing. Compared the study which is above melting point, the study which is below melting point is clearly scarce. The experiments showed that the formation rate of hydrate which is produced by ice was faster, and the gas conversion rate was higher. It was more valuable to the storage and transportation of gas in hydrate.A series of hydrate formation experiments from ice powder were conducted in this paper. The rusults showed that the rate of hydrate formation under the experimental conditions of the pressure of3-10MPa and the temperature of below the freezing point is very sensitive to temperature. Furthermore, the initial pressure has not significant effect on the rate of hydrate formation t at low temperatures. The promoting effect of SDS to formation of hydrate is very obvious. The reaction feature of300ppmSDS is very eye-catching especially. The reaction is quickest, and the complete reaction time is shortest. It shows that the critical period of hydrate formation is the initial reaction. Later, since it is controlled by diffusion, even if the pressure is added, the reaction is difficult to have a fast and efficient conversion when the temperature does not change.Based on the single ice particles shrinking core model and volume diffusion reaction mechanism, this paper proposed diffusion theory of formation of gas hydrate from ice powder. This model considered the variation of the effective diffusion coefficient with time, which was caused by pore structure changes over time in hydrate layer. The concentration distribution function was established according to mass and chemical reaction balance and the mathematical relationship between the ice core radius and the conversion rate with time was obtained. The developed theory can be used in engineering calculations.Finally, this paper calculated the methane gas diffusion coefficient curve in hydrate layer by making use of experiment data in this paper and Andrey N. Salamatin et al’s data. The hydrate formation convertion curve was obtained and compared with experiment results. The developed theory can be used in engineering calculations and offer a reference for high hydrate formation conversion from ice powder.