Experimental Study On Kinetics Of Methane Hydrate Formation

Methane hydrate is an ice-like,non-stoichiometric,cage-like crystalline compound formed by the interaction of gas and water molecules through van der Waals forces and hydrogen bonding.It is one of the most valuable mineral resource to date.If the hydrate storage and transportation natural gas technology is to be industrialized as early as possible,the production rate of methane hydrate must be greatly increased to meet the requirements of industrial production.Therefore,increasing the rate of hydrate formation has important research significance for the application of hydrate method in the field of natural gas storage and transportation.In order to increase the rate of methane hydrate formation and gas storage,the effects of saturated MgSO₄,FeSO₄ and CuSO₄ solutions on the formation rate of methane hydrate at 6 MPa and 2°C were studied.The corresponding experimental data were obtained.According to the analysis of experimental data,the saturated MgSO₄,FeSO₄ and CuSO₄ solutions can significantly reduce the experimental phase equilibrium pressure and increase the gas consumption,and the hydrate in the saturated salt solution at 6 MPa and 2°C.The generation rate is also significantly improved,and the improvement effect is weak to strong.In the natural environment,most of the hydrates are found in the sedimentary pores of the seabed sediments or permafrost zones.In this experiment,four kinds of Al?OH?₃,Zn?OH?₂,Fe?OH?₂ and Cu?OH?₂ particles with the same particle size were used to simulate the porous medium environment in nature,and the surface properties of porous media were explored.Effect on methane hydrate formation.It is found that after the reaction,the porous medium system can accelerate the nucleation rate of hydrate and increase the gas consumption and gas storage density of hydrate compared with pure water system,and the promotion of Al?OH?₃ particles in the four particles is the best effect.In addition,the experiment also examined the effect of permeability of porous media on the formation of hydrates.It was found that after the reaction,the phase equilibrium pressure of methane hydrate is inversely proportional to the permeability of the porous medium,while the gas consumption and gas storage density are proportional to the permeability.In addition,the experiment also compounded the four porous media particles with 500mg/L SDS,and investigated the effect of the porous media+SDS complex system on the methane hydrate formation process.It was found that after the reaction,the phase equilibrium pressure in the compound system was lower than that of the pure porous medium system,and the pressure curve of methane hydrate formation was significantly shifted to the left compared with the porous medium system.Therefore,it can be considered that the complex system of porous medium+SDS has an obvious promoting effect on hydrate formation,and is an effective method for accelerating the rate of hydrate formation and increasing gas consumption and gas storage density.