Development Of A Modular On-Line Corrosion Monitoring Instrument Based On PXI Bus And Research On Key Technologies

Pipeline transportation plays an important role in modern transportation,which is the main means of long-distance transportation of petroleum and natural gas.However,with the use time of the pipeline becoming longer,the pipeline will enter into an accident prone period,which will cause serious economic loss and serious consequences.The same situation also exists in the metal containers of oil refining,pharmaceutical and other process conditions.Therefore,it is of great engineering significance to monitor conduct the corrosion of transportation pipelines and metal containers and to recognize the corrosion situation in time.Field Signature Method(FSM),as a new nondestructive testing technology,has many advantages,such as wide applicable range,high monitoring precision,long service life and so on.The security,sensitivity and flexibility of FSM are better than most of the nondestructive monitoring means.Therefore,FSM have a large number of applications in the oil and gas fields and oil refineries in recent years.However,FSM technology is now monopolized by foreign countries,and domestic related research started relatively late,with less results.Therefore,this paper developed a modularized FSM on-line corrosion detector based on PXI bus,and discussed some problems in the monitoring and calculation process.The main work done in this paper is divided into the following parts:(1)Optimized the optimal electrode connection mode and determine the electrode layout.Through the experiment,a stable and reliable electrode connection method is determined,and the electrode placement scheme and the test method for multiple electrical connections of plate model and pipe model is confirmed by the numerical simulation of electric field distribution.(2)A new FSM software temperature compensation method is proposed to simplify the calculation formula of Fingerprint Coefficient.Through the numerical simulation of the coupling of multiple physical fields,the temperature compensation model of the material is analyzed,the temperature compensation equation is established,and the temperature compensation is realized by embedding the equation into the algorithm.This method eliminates the use of reference plate and has high applicability to different metal materials.(3)Development of a modular corrosion monitor based on the basic principle of FSM.Based on the NI-PXI platform,the hardware part of corrosion monitor was built.Using the different functions of the PXI board realizes the the current control function and the signal acquisition function of corrosion detector;meanwhile,all the board integration in the same PXI chassis,which is a scalable instrument and has the characteristics of good integrity,high stability.Based on the LabVIEW programming environment,the software part of the corrosion detector is completed to realize signal processing,data analysis and data management function.The software interface is a virtual instrument panel with good human-computer interaction.