Liquid Carrying Characteristics Of Natural Gas Condensate Pipeline

In natural gas transportation,due to pressure and temperature changes,part of the fluctuating natural gas pipeline will generate condensate.When the pipeline gas transmission is less than the critical flow rate required for continuous liquid-carrying,the pipeline liquid will block the pipeline and seriously corrode the pipeline and affect the natural gas transmission.Compared with the gas wells liquid-carrying,the research on the pipe flow and liquid carrying theory of the inclined tube is immature.In this paper,the research method combined with experimental research and numerical simulation is used to study the liquid carrying theory and flow characteristics of inclined pipelines.It provides guidance for the parameter design and control of the pipeline transportation system,the prediction of the critical liquid-carrying rate and the pigging operation of the pipeline,makes a reasonable choice.For efficient and safe transport of natural gas which has important scientific significance.The main contents are as follows:(1)A pipeline experiment system with different inclination angles was designed and manufactured.Through this system,the two-phase fluid carrying characteristics of zero liquid flow(ZNLF)can be experimentally studied.Piping full use of visual Plexiglas tube is conducive to high-speed camera to capture the flow of fluid.Liquid flow picture and conductivity probe,the pressure sensor measured the liquid holdup,pressure and provides an important experimental means for simulating the liquid flow of liquid carrying study.(2)The experimental study of the liquid carrying process of the pipeline and find that there is a flow cycle in the pipeline before the liquid is taken out from the pipeline: wave flow-transition flow-annular flow-wave flow,and move back and forth within the upward pipe.The result find that 55 ° corresponding to the most difficult to be carried out of the pipe;For low-volume liquid pipe(fluid holding liquid rate of less than 0.5),as the volume of fluid increases,the liquid climbing required for less speed.(3)The multi-phase flow simulation software was used to simulate the relevant factors affecting the liquid carrying in the pipeline and to simulate the experiment conditions.The experiment was in accordance with the simulation results.The simulation results show that the pressure and the pipe diameter decreases and the down-dip angle increases and the gas flow rate increases will cause the effusion to reduce.On the contrary the pressure and the pipe diameter increase and the down-dip angle decrease and the gas flow rate decrease will cause the effusion to increase.(4)For the different flow patterns in which the effusion is taken out of the pipeline,the non-uniformity of the interface morphology is analyzed.The velocity field equation is adopted for the laminar flow interface,and the annular interface is made up of the lower and thick circular interface,respectively critical continuous liquid carrying model.The experimental data is used to verify the model and the maximum error of this model is within 11%.The research results are summarized to the programming software,with the purpose achieving real-time monitoring of gas pipeline pressure,temperature,whether the fluid blocked.