Study On Dissociation Kinetics Of Gas Hydrate Under Freezing Point

Mine gas,also known as CBM.CH₄,its main ingredient,is a high-burning,clean energy source.It is the finest complementary energy source for conventional gas.China's coalbed methane is rich in resources but unevenly distributed.Conventional gas delivery methods are costly and difficult to fully cover.Hydrate gas storage and transportation have the advantages of high gas storage capacity,mild conditions,safety and stability.It is necessary to strengthen the research on gas storage through the gas hydrate method.In view of this,based on the on-line gas hydrate Raman test system,a multi-system gas hydrate dissociation experiment has been carried out based on CH4 concentration of feed gas,accelerant and temperature below the freezing point.In addition,data such as temperature and pressure were obtained during the experiment.The influencing factors on the rate of gas hydrate dissociation,dissociation percentage and other parameters were obtained.Combined with laser Raman spectroscopy,gas chromatography and other instrumental analysis methods,the dissociation dynamic laws of gas hydrate under the influence of multiple factors were obtained.It provides experimental support for revealing the microstructure of gas hydrate dissociation process and structural transformation rules,determining the storage and transportation process conditions,and enhancing hydrate gas storage research.The gas hydrate dissociation experiment results show that gas hydrate has self-protection effect below the freezing point.The maximum dissociation rate may occur at any point in the dissociation reaction.The decomposition rate fluctuates regularly,and the fluctuation cycle increases with the decomposition reaction.The fluctuation frequency increases with the decomposition temperature.In the same dissociation time,increasing the concentration of CH4 in the feed gas can effectively increase the gas content in the gas hydrate,and the order from the largest to the smallest:SDS>THF>TBAB>CP.The purification of CH4 gas can be achieved through gas hydrate generation and dissociation.Laser Raman spectroscopy was used to qualitatively analyze the crystal structure of gas hydrates with accelerators,quantitatively calculate the proportion of CH₄ molecules in large and small holes in the hydrate phase,and monitor the structural transformation of the gas hydrates during the dissociation process and the self-protection effect produced by the dissociation below the freezing point.It provides a reference for strengthening the research of gas hydrate storage and transportation.