Analysis Of Multiphase Flow Containing CO₂ Corrosion Assessment Technology

At present,corrosion in the pipeline is one of the main influence factors of pipeline failure,so it needs to analysis the pipeline internal corrosion influence factors,and through the pipe of detection technology for pipeline detection,pipeline can be timely and effective understanding,pipeline internal corrosion direct assessment at present basically has the United States institute of corrosion engineers?NACE?of dry gas pipeline internal corrosion direct assessment?DG-ICDA?and moisture pipeline internal corrosion direct assessment?WG-ICDA?for multiphase flow pipelines requires for its internal corrosion direct assessment method,so this article make multiphase flow pipeline containing CO₂ as the research object,exploring internal corrosion direct assessment methods containing CO2multiphase flow.Begin with CO₂ corrosion mechanism research,this paper analyzes the fluid temperature,CO2 partial pressure,fluid velocity,flow pattern,ion concentration,and the pH value,moisture content and oil content of fluid,corrosion product film and other factors.And compare and analysis De Warrd75,De Warrd93,BP,Ohio,Norsok predict model.For the study of corrosion protection at present,there are the preliminary design,corrosion detection,anticorrosive process corrosion protection measures for analysis.Reference has been established and the practical application of dry natural gas,wet natural gas and crude oil pipeline internal corrosion direct assessment method,established the pipeline containing multiphase flow,internal corrosion direct assessment technology mainly divided into four stages:pre-assessment,indirect evaluation,detailed inspection,post evaluation.Analysing real case shows that pipeline containing CO₂ multiphase flow internal corrosion direct assessment technology,the pre-assessment phase acquire pipeline parameters,operation parameters,fluid physical properties,such as pipe operating data,indirect evaluation fluid temperature calculated by numerical simulation,pipe pressure changes,superficial gas velocity,liquid superficial velocity,the changes of fluid's pH value,CO2partial pressure,gas liquid phase flow pattern changes,gas liquid ratio,corrosion rate changes,analysis tube corrosion rate is the combination result of the above factors.Detailed inspection phase in by pigging and detection work to understand the pipeline corrosion situation,evaluation stage according to detailed inspection result after evaluation.Finally based on the optimized Norsok model to calculate the CO₂ corrosion prediction,it can calculate corrosion rate according to the basic parameters,it also provides CO₂ internal corrosion direct assessment with certain reference and effective technical support.