Study Of The Law Of Oil-water-replacement Contamination Volume Of A-M Product Pipeline

Since the product pipeline is completed,an oil-water-replacement process is conducted,which leads to a lot of oil-water mixture in the final end.A slop tank is needed in the final station to store the mixture.However the size of the tank is normally set according to experience.In the case of drastic undulating pipelines,the rolling ground and unexpected shutdowns will result in huge deviation between the experience-based prediction value and the real volume?leading to economic loss or interruption of production.Therefore,research on the rules of oil-water-mixing in the oil-water-replacement process of drastic undulating pipelines is of great importance.The replacement process falls in the study of liquid-liquid multiphase flow.Therefore,based on the theory of oil-water two phase flow,this research builds an oil-water-replacement model for product pipelines adopting the oil-and-water two-phase flow model.Kelvin-Helmholtz flow pattern conversion model,modified diesel-water viscosity model and reverse phase point model,which are suitable for diesel.The numerical model is verified in OLGA based on the modified oil-water model using the operating data and mixture result of A-B pipeline.In light of the numerical method,multi operating conditions of the oil-water-replacement of A-M pipeline is simulated,including multiple flow rates,various shutdown time spans and different positions of contamination head when the system is stopped.According to the large number of simulation results,a contamination volume calculation program is designed.shading light on the prediction of oil-water mixture volume.This paper,utilizing the oil-water two-phase flow numerical model of product pipeline,simulates multi operating conditions of A-M pipeline's oil-water-substitution.The results show that flow rate is the most important factor in the substitution progress.The higher the flow rate,the smaller the mixture volume.The shutdown time span of the substitution progress has a critical value,above which the volume of oil-water mixture would not grow as the time span increases.The law of the impact of flow rate and shutdown time span can be demonstrated in quadratic functions.The impact of the contamination position on mixture volume should be related to the inclination of the pipe where the contamination section is.A program aiming to predict the mix volume of oil and water is compiled,which offers reference to the oil-water-replacement progress.