Research On Corrosion Evaluation Method Of Tank Floor Based On Acoustic Emission Detection

In the process of oil production,storage and transportation,there are many kinds of storage tanks for storing petroleum.Because of the corrosiveness of these oils,the bottom plate of crude oil storage tank will be damaged or have active defects with the change of time.Serious leakage of the tank will also occur,which will lead to pollution of the environment and fire and explosion accidents.The bottom of the tank is one of the major hidden dangers of the accident,which has the characteristics of high detection difficulty and high detection cost.Aiming at the corrosion phenomena of tank bottom,based on acoustic emission technology,the acoustic emission corrosion test was designed and carried out.The corrosion evaluation method of the tank bottom plate based on acoustic emission corrosion signal is proposed,and the corrosion degree of the bottom plate of several crude oil storage tanks is evaluated by the example analysis.The above issues were carried out in the following aspects:(1)Aiming at the problem of corrosion detection of tank bottom plate and corrosion,there are many noise interferences,etc.,a tank bottom plate corrosion simulation device is designed and manufactured,which can realize accurate and efficient acquisition of acoustic emission signal of tank bottom plate of simulation device.The purpose is to more easily and accurately detect the corrosion of the bottom plate.(2)In view of the difficulties in testing crude oil storage tanks under liquid loading.a corrosion degree evaluation method based on on-line detection of acoustic emission is proposed.The characteristic parameters obtained by acoustic emission detection are corrosion data.The corrosion degree of the bottom plate of the simulation device is evaluated by characteristic parameter analysis to determine the main range of the special diagnosis parameters when the corrosion occurs,and the thickness of the bottom plate of the simulation device is detected by the ultrasonic thickness gauge.The influence of different media on the corrosion of the bottom plate of the simulation device is analyzed to determine whether the addition of chloride ions has an influence on the corrosion of the bottom plate of the simulation device.(3)It is difficult to detect crude oil storage tanks under liquid loading conditions.The corrosion evaluation method of tank bottom plate based on extreme learning machine is proposed.The case of three crude oil storage tanks is analyzed.Through the on-line detection of acoustic emission of the target storage tank,comprehensive evaluation is carried out from the tank floor with or without corrosion..Leakage magnetic scanning inspection was carried out on the storage tank with high corrosion severity,and the corrosion of the tank bottom plate was quantitatively evaluated.The reliability of acoustic emission detection was determined by comparative analysis.Taking the acoustic emission corrosion signal parameters as the training samples,the prediction model of the corrosion level of the tank floor based on the extreme learning machine is established.The corrosion grade is graded and predicted by the corrosion degree of the tank floor,and the comprehensive evaluation is carried out.The results of the evaluation of the launch are compared to verify the accuracy of the method.