Molecular Dynamics Simulation Of Methane Hydrate Decomposition In The Presence Of Chemical Additives

Methane hydrate contains high purity methane and water,which is an important strategic resources that can effectively relieve the energy crisis.Methane hydrate decomposition dynamics research involving the hydrate exploitation technology has been the focus of scholars around the world.This article adopts the method of molecular dynamics simulation,type I methane hydrate decomposition kinetics was studied and discussed the temperature and chemical additive(methanol)on the microstructure and the effects of decomposition rate.At first,style I methane hydrate is the object of research,the influence of temperature on water molecule sequence parameters and radial distribution function is studied,the result shows that in the process of hydrate decomposition,water molecules structure is evolved from the original long range order to long-range disorder and short-range ordered,and is converted from crystal structure of low density to liquid water of higher density.The temperature of system increases from 270 K to 295 K,carbon-carbon atoms of methane molecules in the radial distribution function of peak showed a trend of increase,shows that the higher the temperature,the faster the rate of methane escape out of the cage.The study found that in the process of decomposition dynamics of evolution,the AOP sequence parameters of water molecules begin to rise from 0,stabilize near 0.8.The higher the temperature,the steeper the curve in decomposition of AOP,the faster decomposition of methane hydrate.Then the methanol-methane hydrate composite system model was built,5.9 wt % methanol aqueous solution was added in the axis Z of methane hydrate,the influence of methanol on the hydrate decomposition rate are discussed,the results showed that after adding chemical agents methanol hydrate decomposition rate can increase 2-3 times.Studies have shown that the effects of chemical additives on decomposition rate is related to temperature,when the system temperature is 270 K after adding methanol hydrate decomposition rate increased 2.9 times,when the system temperature is 295 K the decomposition rate increased 2.2 times,in other words the effects of additives of methanol to hydrate decomposition rate decreases with the increase of temperature.