Research On Erosion And Wear Of Natural Gas Gathering And Transportation Pipeline Tee

Because of sand production in the gas field and the exfoliation of corrosion products on the inner wall of pipelines,a certain amount of solid particles will be found in the natural gas gathering and transportation pipeline.The tee is mainly used for connecting pipelines,and solid particles will move with the movement of the gas flow in the tee.The long-term operation will lead to erosion of the inner wall of the tee,which brings great potential hazards to the safety of gathering and transportation pipelines and the surrounding ecological environment.Aimed at the problem of erosion failure of the tee in gathering and transportation pipelines,the erosion rule of the tee is analyzed,and the anti-erosion method of the tee is studied in this paper,by means of the experiment and numerical simulation,which is of great significance to ensure the safe operation of the natural gas gathering and transportation pipeline.On the basis of literature and investigation,the material,specification and flow direction of the tee are determined,and a set of gas-solid two-phase flow erosion pipeline experimental device suitable for the tee is set up.The device mainly includes an energy supply unit,a flow monitoring unit,a sand adding unit,a test unit and a gas-solid two-phase separation unit.The energy unit can provide a flow velocity in the range of 0 to 30 m/s,and the test unit is a tee with 45 erosion rate measuring points.The erosion experiments at different velocities are carried out by the device.The electronic balance is used to weigh the specimens before and after the erosion experiment,and the erosion rate at each measuring point is obtained by weight loss method.SEM is used to observe the surface morphology of specimens at key positions after the erosion experiment.As the experimental conditions will be restricted by the specification and flow direction of the tee,the numerical simulation should be carried out to study the erosion rule of tee under other working conditions.The continuous phase motion equation and discrete phase motion equation are established to describe the distribution of the gas phase flow field and the trajectory of solid particle movement respectively.The E/CRC equation is used to predict the erosion rate.The ICEM software is used to build the tee geometry model,and divide the OBlock structured mesh,at the same time the best grid scheme is selected by grid independent verification.The numerical simulation of erosion of the tee under experimental conditions is carried out,and the numerical simulation results are compared with the experimental results to verify the rationality of the numerical simulation model.The numerical simulation of erosion of the tee under different flow velocities,flow directions,pressure and pipe diameters is carried out based on the actual working conditions in the field.According to the erosion characteristics of the tee,combined with the experience of the previous research on erosion prevention,the structure of the tee was improved,and the numerical simulation of erosion of the improved tee is carried out under the different flow directions.The ratio of the maximum wear rate and the ratio of the average wear rate between the improved tee and the common tee are introduced as the evaluation index of erosion reduction.,and the anti-erosion effect of the improved tee is analyzed.In summary,by experiment,the change rule of erosion rate of the inner wall of the tee with different positions is obtained in axial direction and circumferential direction,and the damage types and erosion wear mechanism of the material are determined.The influence of flow direction,velocity,pressure and pipe diameter on erosion wear of tee is obtained by numerical simulation.Through the improved design of the tee structure,an improved tee with the function of reducing erosion is obtained.The above-mentioned research results have important engineering significance to the field application and prevention of erosion wear of the tee in the gathering and transportation system of the gas field.