Influencing Research Of Throttling Process On Natural Gas Hydrate Formation

Now in China, Pipeline transportation is the main transport way. When reducing pressure transferring is needed in the process of pipeline transportation, the throttle way is mostly used to reduce the pressure. However, as for the process of the throttling of the air, after throttling,the temperature of the air is reduced. The whole process is very fast and the drop of temperature is large, which can cause the formation of gas hydrate and result in terrible security risk.The studies of this paper are carried out on the basis of this problem, which analyzes the effect of the different parameters on the formation of gas hydrate in process of the throttling.Among these effects on the formation of gas hydrate, the effect of temperature drop effect in the process of throttling is the main one, so, this paper will get further study on the mechanism of temperature drop and throttling parameters in the throttling process and give an analysis from the perspective of thermodynamic and energy conversion. Use BWRS equation of state to solve the throttling coefficient and temperature drop, obtain the calculation result according to the actual conditions of which the error is 2.4%. Use the calculation results to solve the correction factors of throttling temperature drop project calculation method under the same condition. The result of correction factors is 2.67 has large difference with the range of correction factors is 0.8~0.9 according to projects. That proves the correction factors change along with starting condition before throttling. The error of temperature drop is large if use the range of correction factors according to projects.Numerical simulation is used to simulate the process of the phase transition process of methane gas at the throttling position. Use the solidification and melting model to simulate the generation of solid methane and observe the variation of temperature and pressure. There are two ways to make the generated heat solid methane dissociation: heating the gas temperature before throttling and heating the pipe temperature after throttling. The hydrate melting process and the dissociation rate are observed. After contrast, the conclusion is that the utilization of geothermal energy is higher and the dissociation rate is faster when pipes are heated.Finally, according to the results of this paper, combine the characteristics of the formation of the gas hydrate in the throttling process, and throttling temperature drop calculation equation, proposed in view of the throttling after heat load calculation method of the pipe to prevent hydrate formation.