The Dynamics Research Of Methane Hydrate Restricted In Nanoscale

Energy is very important to human survival and development, and it is the material basis of human survival. In current our main energy is natural gas, oil and coal, however, these reserves are dwindling, in order to prevent energy depletion, researchers are trying to develop efficient and clean new energy which has abundant reserves. Natural Gas Hydrate, also known as methane hydrates, the molecular structure is CH4·H2O. Under high pressure and low temperature conditions, the water and methane molecules form to the ice-like crystalline material. Nominal methane clathrate hydrates per5.75moles of water contain one mole of methane. Methane is a flammable gas, ignition is very low, with highly flammable, and it is a clean energy, does not pollute the exhaust gas after the combustion. According to estimates, methane hydrate is about2-10times of natural gas, and per cubic meter of methane hydrate would release about168cubic meters of methane gas. Although the discovery of methane hydrate has more than200years, until the last50years, scientists began to study its formation mechanism in depth from the micro-level. Since methane hydrate condensation nuclei is very small, experimental methods can not dynamically track the trajectory atoms for now, thus desired to achieve the forming mechanism and dynamic behavior of the of methane hydrate through experiments at the atomic level is difficult. The current effective method is using molecular dynamics simulations to simulate the formation and evolution of methane hydrate, and clarify the physical mechanism. So the study of methane in the confined space of water environment is very important.Moreover, in recent years, through continuous research, we have found that water molecules in the nano-scale and macro nature manifested with a big difference. In currently, understanding things from the nanometer level has been a hot research, and the research of water molecules in the nano-passage also requires us to control and understanding in molecular level. Water molecules limited in the nanometer pore have many outstanding features, such as the additional rapid movement and orderly flow of water structure. Water molecules in carbon nanotubes demonstrated those superior physical properties laid the foundation for the development of nano-transport technology. Most importantly, these advantages open up a new area of research.We have already knew the study of water molecules confined in carbon nanotubes and the spontaneous nucleation and growth processes of large volume of methane hydrate. However, we still do not know the nature of the water and methane molecules limited in nano-environment space.This article use the molecular dynamics simulation method, for further study of properties and dynamical behavior of methane and water molecules limited in carbon nanotubes, the main contents are as follows:In the first chapter,we introduces the background and the current knowledge of carbon nanotubes and methane hydrate, describes the main research method and contents.The second chapter briefly describes the molecular dynamics, including a brief history of molecular dynamics, the main advantages and limitations, the basic principles, the potential function and force field, the equations of motion, equilibrium system simulation, the initial conditions and boundary conditions.The third chapter we designed a serial systems, methane and water molecules are limited in carbon nanotubes, changing the density and observe the distribution and dynamics of methane.The fourth chapter studies the character of water molecules flow a serial of charged carbon nanotubes by using the method dynamics simulations, by adjusting the charge of carbon nanotubes to study the nature and dynamics of water molecules confined in the charged the carbon nanotubes.The fifth chapter, the summary and outlook of this work.