Design Of The Corrosion Monitor For Underground High Temperature Environment Based On CAN-Bus

The corrosion of pipelines for oil and gas transmitting is one kind of common wear,which results in a very large proportion of accidents and financial losses in petroleumindustry, hence the cost caused by corrosion is difficult to be estimated. Therefore, theprediction, measurement and control of corrosion become urgent need of all walks of life,including petroleum industry, in order to reduce the loss of corrosion.This thesis introduces a corrosion monitor for underground high temperatureenvironment, based on CAN bus, and combined the advantages of linear polarization andAC impedance method. The design of this monitor is relies on relevant principles ofelectrochemical corrosion, combined with the application of electronics, computer andnetwork technology. The core of the instrument is a microcontroller of C8050F serieswhich are made by the Silicon Laboratories. Impose the measuring system sinusoidalsignals at different frequency, sample the voltage and the current signals by the ADconverter inside the MCU. Then we can calculate the polarization resistance and solutionresistance of the system according to the circuit and chemical formulas to analyze thecorrosion status. The instrument works in the underground, high temperature and highpressure environment, it communicates with the controlling centre on the ground via theCAN bus for reporting the real-time corrosion status.This thesis detailed introduces the design of the hardware circuit and the MCUcontrolling program, and shows the result of measuring experiment in normal environmentand laboratory simulation of high temperature environment.In addition, the design of this instrument is different from the ordinary instrument, inorder to adapt the hash working environment, there is much special design, including theexternal part and internal part and so on. To make the instrument suitable to gounderground, the chassis must be designed for the long cylinder shape and use stainless tobe made for shell, cable interface through a metal slip ring. The internal circuit must adaptto the high temperature environment, so choose a special temperature devices and relateddesign.