Transient Simulation Analysis Of Long-distance CO₂ Pipeline Blockage

Pipelines are one of the most cost-effective and safest options for long-distance CO₂.Thermodynamic products,accumulation of solid impurities or other blocking materials,deformation of pipelines or other failures inevitably cause pipelines block.It not only affects working stability,reduces transportation efficiency,but also causes serious accidents such as overpressure explosion.Therefore,it is of great research significance to seek an effective and practical method for transient simulation analysis of CO2 pipeline blockage while performing localization and quantitative detection.The long-distance CO₂ pipeline is taken as the research object.Based on the principle of transient pressure wave reflection,from the purpose of blockage detection,a combination of theoretical analysis and numerical simulation is used to study the influence of blockage on the parameters related to unstable flow of the pipeline.A physical model of the CO2long-distance pipeline containing limited incomplete blockage was established.A measurement and numerical method for determining the blockage parameter using the pressure wave method was obtained.First,It is found that no matter what phase state and blockage model,as long as the blockage occurs,transient pressure waves and flow waves will occur from a transient comparison study.A sudden change and trend is basically the same under the three-phase and each blocking model.Repeated fluctuations occur at the initial moment of the characteristic point.Finally,the damping effect returns to a stable state,which is different from no blocking CO2 pipeline.Secondly,the transient pressure wave changes caused by the blockage of the CO₂pipeline,and further quantitative analysis.After numerical simulation verification,the time and amount of sudden pressure changes at two peaks and one trough of the transient pressure wave can be used to determine the blockage location,length,and Blocking amount.This method can locate and quantitatively analyze the clogged pipes of CO2 which have a high and simple accuracy.Finally,the influencing factors of the accuracy of the blocking characteristic parameters are analyzed.The measurement accuracy of blocked position of the CO2 incompletely blocked pipeline is mainly affected by the monitoring point and the blocking position.The closer monitoring point and blocking position to mass pulse point,the higher measurement accuracy;When monitoring point is at the entrance of the pipeline,accuracy is as high as0.8016%,and when the distance is close to pulse point,accuracy is as high as 0.722%.The measurement accuracy of length of the CO₂ incompletely blocked pipeline is mainly affected by the monitoring point and its length.The closer clogging position and longer the clogging length,the higher measurement accuracy.When monitoring point is close to clogging position 50m,the accuracy is 0.535%.When clogging length is 500m,measurement accuracy is as high as 0.341%.The measurement accuracy is affected by many factors.The larger plugging strength,the higher measurement accuracy.When plugging strength is above 50%,the error can be accurately measured with an error of 0.The research proves that the transient pressure wave method can be applied to the detection of long-distance CO₂ pipeline blockages.According to the research results,it is recommended to set the monitoring points at the entrance of the CO₂ long-distance pipeline and near the front end of the blockage location to obtain more accurate pipeline information about internal blockages.