| Continuous corrosion inhibitor is one of the commonly used means to control corrosion problems for gathering pipelines in high-sulfur gas fields.It refers to inject corrosion inhibitor into the gathering pipelines continuously during the production process to repair the batch film.In addition,whether it really works depends on the movement and distribution of the corrosion inhibitor droplets in the pipeline.At present,there are few studies in this area at home and abroad,and it is impossible to effectively evaluate the corrosion inhibition effect and optimize the corrosion inhibitor filling system.Based on Computational Fluid Dynamics(CFD)methods,complet the distribution law of corrosion inhibitor in gathering pipeline.The main research works and conclusions are show as follows:(1)Investigate the research status of numerical analysis and experimental research methods of concentration distribution of corrosion inhibitors at home and abroad.Make research of the basic data and production operation data of M gathering pipeline.Meanwhile,some deficiencies existing in current researches,such as lack of studies on the gathering and transportation system of highly sulfur-containing gas field,the corrosion inhibitor concentration test device can't simulate actual conditions fully.(2)The finite element calculation model of corrosion inhibitor concentration distribution was established,and the fluid domain was extracted and the structural mesh was built.The finite volume discrete equation was established by Fluent,and the SIMPLE pressure velocity coupling algorithm,second order upwind,the K-Epsilon model and the DPM model were used.Grid independence and model validation were tested and verified.(3)Simulate the distribution of corrosion inhibitors in pipes under different working conditions,study the distribution law of corrosion inhibitors along the axial,circumferential and different sections of the pipeline,and analyze the factors such as the amount of corrosion inhibitor,the injection speed and the droplet size.Effect of concentration distribution.Based on the understanding of the law of corrosion inhibitors changing with the flow conditions,suggestions and measures for prolonging the migration distance of corrosion inhibitors.(4)Study on the concentration distribution characteristics of continuous injection inhibitors in M gathering pipeline,inject corrosion inhibitors continuously are most easily distributed unevenly in horizontal pipes,and vertical pipe sections are more uniform.The distribution at the top of the pipe is the least and the bottom is the most.The pipe flow will form a secondary flow at the upper and lower bends,which is beneficial to the uniform distribution of the corrosion inhibitor on the inner wall of the pipe.(5)Analyse the damage of gas scouring on the corrosion inhibitor film in gathering pipeline,the The most serious position where the bend inhibitor film breaks is on the outside of the bend,The most severe damage zone of the tee is at the entrance of the branch pipe.As the diameter of the branch pipe becomes larger,the degree of damage is reduced,two symmetrical distributions of the destructive concentration zone are formed at the bottom of the straight pipe section of the split tee.(6)Calculate the number of days of corrosion inhibitor film erosion in the gathering pipeline M,combined with the concentration distribution characteristics of the corrosion inhibitor in the pipe,the repairing and replenishing effects of the continuous corrosion inhibitor on the corrosion inhibitor film were evaluated,and the high-risk area of corrosion eaused by the failure of the corrosion inhibitor film was identified.(7)Design a corrosion inhibitor concentration distribution test device program,complete the detailed design of the test module for corrosion inhibitor pre-filming,filling,pressure regulation and temperature adjustment,concentration distribution,corrosion inhibitor film thickness,pipe inner wall corrosion,etc.,select the key equipment,and form a supporting test and the test process. |
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