Study On Pipeline Flow Characteristics Of Natural Gas Hydrate Slurry

With the increasing maturity of marine natural gas hydrate development technology and the widespread use of natural gas energy,compared with traditional natural gas pipeline transportation,natural gas transportation in the form of hydrate slurry will become a more efficient way.Therefore,it is necessary to conduct an in-depth study on the flow characteristics of natural gas hydrate slurry,to ensure the safety of the hydrate slurry pipeline transportation process,and to provide theoretical support for the practical application of natural gas hydrate slurry pipeline transportation,seabed hydrate mining,and future hydrate applications.In order to make the research results more realistic,this paper uses the phase equilibrium pressure and particle size provided by the experiment of the natural gas hydrate phase equilibrium and the FBRM to simulate the flow of hydrate slurry flow as the basic data.The two FLUENT numerical simulations analyze the factors affecting the smooth transportation of natural gas hydrate slurry pipeline.The simulation results are as follows:1)According to the experimental gas hydrate phase equilibrium conditions,combined with Rabinowitsch-Mooney fitting formula and Euler-Euler model,the effects of initial flow rate and volume fraction on macroscopic flow state and the critical distance of hydrate decomposition are simulated.It shows that the gas hydrate slurry flows in a solidified bed under simulated conditions.In order to prevent the increase of the deposition rate and the increase of the solidified bed,the flow rate of the hydrate volume should be increased as much as possible below the critical value.2)According to the Euler model in the discrete element method,the vertical bending system with horizontal pipe and inclined pipe is numerically simulated.The particle size of natural gas hydrate is obtained through the FBRM experiment,and the simulation results are compared with the experimental results to prove that The feasibility of the model.Taking the volume fraction of 7% when the hydrate slurry undergoes heterogeneous transformation as the critical volume fraction that is prone to pipe blockage,the changes of the volume fraction of hydrate particles in the vertical elbow system,and the changes of the flow rate and the diameter of the pipe to the volume fraction are analyzed.In order to prevent the blockage of hydrates in the same pipeline system,small diameter and large flow pipelines should be selected.