Study On Distribution Of Corrosion Inhibitor For M Gathering Pipeline

M pipeline transport fiuld contains high H₂S and CO₂,and pipeline has corrosion risk.Continuous injection of corrosion inhibitor is used as one of the anti-corrosion technologies.At present,little research has been done on the distribution of liquid film of corrosion inhibitor in pipeline and its changing law with the flow condition.It is impossible to give full play to the anticorrosive effect of corrosion inhibitor.The low dosage of corrosion inhibitor can easily lead to uncontrolled corrosion.The excessive dosage of corrosion inhibitor leads to a large number of residual corrosion inhibitors in the system.Therefore,it is of great significance to study the concentration distribution of corrosion inhibitors in gas gathering pipelines,analyze the influencing factors,and put forward suggestions or measures to extend the protection distance of corrosion inhibitors,which will slow down the corrosion rate of gas gathering pipelines and prolong the service life of equipment.?1?Investigate the research status of corrosion inhibitor application,corrosion inhibitor filling method and corrosion inhibitor distribution at home and abroad,and summarize the current research.There is no calculation model for flow field calculation and numerical simulation of concentration distribution of corrosion inhibitor in tube.Research and other aspects.?2?The Corrosion Inhibitor Corrosion Inhibition Mechanism,Corrosion Inhibitor Film Formation Mechanism,Corrosion Inhibitor Atomization and Numerical Simulation Theory were analyzed.Gambit software was used to establish M pipeline mathematical geometry model to complete computational fluid domain extraction and structured mesh division.Fluent establishes a finite volume discrete equation,QUICK difference scheme and SIMPLE algorithm to solve the governing equation.The gas-liquid two-phase turbulent motion in the gas pipeline adopts the k-? model,and the DPM model is used for the complex movement of the corrosion inhibitor droplets entering the pipeline in the natural gas.?3?Under the current operation condition of M pipeline,after the corrosion inhibitor enters the pipeline from the entrance,it will be affected by gravity,and the relative movement will be deviated from natural gas.Then it will gradually settle at the bottom of the pipeline.The farther away from the entrance,the more the corrosion inhibitor settles.The larger the corrosion inhibitor dose is in the lower half of the pipeline.At about 10m from the entrance,the concentration of corrosion inhibitor at the top of the pipeline is basically zero,which can not play an effective role.Protective effect.?4?Under different operating conditions,the migration of corrosion inhibitors at different positions in the pipeline is as follows:the gas flow of the pipeline increases,the protection distance of corrosion inhibitors increases,the protection distance of corrosion inhibitors at the bottom of the pipeline is larger than that at the middle and top;the migration distance of corrosion inhibitors in the pipeline increases with the decrease of the size of corrosion inhibitor droplets;the higher the spraying speed,the better the pipeline corrosion protection,and the better the pipeline top.The distribution of corrosion inhibitors at the bottom of pipeline has little effect;with the increase of the amount of corrosion inhibitors,the concentration of corrosion inhibitors at the bottom of pipeline increases,but has little effect on the concentration of corrosion inhibitors at the middle and top of pipeline.?5?Put forward Suggestions or measures for extending the protection distance of corrosion inhibitors:It is necessary to increase the amount of corrosion inhibitors added and optimize the injection speed according to the gas transmission capacity,increase the injection point at the appropriate location to ensure that the corrosion inhibitors are better attached to the whole pipeline for gas pipelines with small gas transmission capacity;It is necessary to increase the injection speed of corrosion inhibitors and optimize the injection amount according to the distribution and corrosion of pipelines for pipelines with large gas transmission capacity.For corrosion detection,additional injection points should be added at appropriate locations,and the structure of corrosion inhibitor injection nozzle should be further improved to reduce the nozzle diameter and the droplet size of corrosion inhibitor.