Study On Utilization Technology Of Natural Gas Hydrate

The main application fields of natural gas hydrate technology include natural gas storage and transportation,natural gas extraction,gas separation and hydrate cold storage.Among them,natural gas hydrate garner and carriage methods is to make natural gas into hydrate and store natural gas with hydrate.Compared with the currently mainly used natural gas storage and transportation methods,hydrate technology has the advantages of high safety,large gas storage capacity and high economy.The development of natural gas hydrate technology is important,but the problem that limits its development lies in the efficient preparation of hydrate.At present,the research on natural gas hydrate technology at home and abroad mainly focuses on hydrate laboratory preparation and theoretical research.In order to improve the efficiency of hydrate preparation,expand the scale of preparation,expand the application of hydrate technology,and improve the link of hydrate technology,a series of studies have been done.The main contents are as follows:1.In order to improve the preparation efficiency of natural gas hydrate,spiral inner grooved tube reactor Combined with the theory of fluid computational mechanics.Fluent software was used to simulate and calculate the different pipe diameters(33 mm,37.92 mm and 42.3 mm),the number of thread heads(4,6 and 8)and the thread top width(5 mm,6 mm and 7.5 mm)in the tube:Under the action of centrifugal force in the spiral inner grooved tube,the gas-liquid-solid three-phase distribution in the tube is different due to different densities.The liquid phase is mainly distributed on the tube wall,and the gas-solid phase is mainly distributed in the tube.The accumulation of hydrate on the wall will affect the gas-liquid contact and the removal of reaction heat.Under the action of the spiral tube,the accumulation of hydrate on the wall is avoided and the better heat transfer.With the increase of the number of thread heads,the inner and outer diameter of the spiral tube decreases,the width of the thread top decreases,three-phase separation is better,and the mass transfer efficiency is improved.2.The hydrate preparation process was explored through experiments.The experiment used coalbed methane and water as the main reaction raw materials to explore the effects of different reaction conditions on the preparation of natural gas hydrates:With the increase of pressure and the progress of the reaction,hydrate reaction rate and gas storage increased.Properly increasing the pressure and prolonging the reaction time is helpful for the preparation of hydrate;with the increase of the surfactant SDS concentration,hydrate reaction rate and air content were investigated hydrate first increased and then decreased,and the concentration reached a peak at 300 ppm.When SDS is not added to the reaction solution,no hydrate is produced in the reactor,and the reaction cannot proceed.Appropriate addition of a certain concentration of SDS additives is conducive to the formation of hydrate.3.Aiming at the problem that BOG in LNG storage is difficult to deal with,a new BOG treatment process is designed using natural gas hydrate technology to recycle BOG and cooling capacity in LNG storage.This process is based on the designed natural gas hydrate preparation system,and recycles the BOG that is difficult to handle in the LNG storage,so that the BOG is stored in the form of hydrate.The utilization of material energy in LNG storage is improved.4.In order to store natural gas hydrates stably for a long time,an underground natural gas hydrate storage is designed.Compared with the ground,the underground storage saves the ground space.In addition,the soil is insulated,the thermal insulation performance of the underground storage is stronger.