Remaining Life Prediction Technology Research Of Tank Bottom Based On Risk Corrosion Rate

Atmospheric vertical storage tank is important storage devices of raw materialsfor petrochemical industry such as crude oil, refined petroleum and intermediateproducts. Tank floor corrosion state is a main factor of tank safe operation, its severityis the leading indicator which guides tank maintenance decision-making, and the tankbottom corrosion state testing is the main method to ensure tank run smoothly in thenext cycle. In view of the special operating environment of tank bottom, acousticemission online testing and magnetic flux leakage testing are the main method fortank bottom corrosion evaluation in international. But acoustic emission testingmethod of tank bottom corrosion state is still staying in qualitative evaluation stage,and although magnetic flux leakage testing technology can effectively solve thequantitative and orientation problem of tank bottom corrosion defects, excessivemaintenance and unnecessary waste are easily to occur. In order to ensure the safeoperation of tank, avoid unnecessary open testing, reduce the incidence of accidents,remaining life prediction technology method of tank bottom corrosion based on riskcorrosion rate is established, acoustic emission online testing for the quantitativeevaluation of tank bottom corrosion and remaining life prediction can be realized.By comparing the15tank of acoustic emission testing and magnetic flux leakagetesting results, it is determined that acoustic emission testing and magnetic fluxleakage testing results have good consistency, the reliability of acoustic emissiontesting technology for the tank bottom corrosion was verified, which can be used forthe future research.Basing on the amplitude distribution theory, statistics theory and the risk concept,acoustic emission testing and magnetic flux leakage testing data of tank bottomcorrosion are comprehensively analysed, acoustic emission parameters of tank bottomcorrosion quantitative method based on the magnetic flux leakage testing data isestablished.By the analysis of10tanks which are in a region and the medium are crude oil,the acoustic emission typical parameters for tank bottom corrosion quantitativerelationship is obtained, the relationship of acoustic emission activity and riskcorrosion rate CRP is y=13514.65x, and the evaluation accuracy of the model is 90.22%.The relationship model of true corrosion pace CTP and risk corrosion pace CRPhas been established, which is z=12.14x, the conclusion that the12times of the CRPis about the worst parts of the tank bottom corrosion rate is obtained. Thus usingacoustic emission testing to evaluate tank, applying the quantitative evaluation modelof acoustic emission, CRP and managed corrosion pace CMP can be got, the basis fortank management and maintenance decision-making can be provided. Comparativelyanalysis between tank bottom corrosion life prediction method based on risk corrosionrate and the tank bottom corrosion life prediction method based on the Gumbelextreme value, both of the prediction results were consistent, the reliability of tankbottom corrosion life prediction method based on risk corrosion rate has been verified.From the application background of tank group of corrosion damage predictionanalysis and comprehensive information management, the tank bottom corrosion stateevaluation and life prediction system has been developed, which benefits for realizingthe refinement of tank group safety management.