Research And Development Of High Temperature Pipes’ Wall Thickness On-line Monitoring And Management System

In the petrochemical, coal chemical industry, the problem of multiphase flow’s corrosionand erosion is widespread, cause the equipment and pipe’s wall thickness reduction anddielectric leakage frequently, especially in the bad crude oil or coal to oil process, local scourperforation is main cause of device unplanned shutdown and fire, explosion accidents. Hightemperature pipes’ wall thickness on-line monitoring is a focus in engineering, and also aresearch focus in the field of theory. Combined with the enterprise’s actual demand, we researchand develop the system of fixed-point and on-line monitoring of high temperature pipelines’wall thickness and its auxiliary system based on SH ultrasonic guided wave, and so provide thetheoretical basis for high temperature pipelines’ wall thickness monitoring technology.The research work is divided into three parts: first, analyze the background of hightemperature pipe wall thickness on-line monitoring and research significance, elaborate the wallthickness monitoring method and principle of high temperature pipe at home and abroad,determine the ultrasonic guided wave pulse reflection principle as the basic method formeasuring wall thickness, according to the propagation time and velocity of ultrasonic guidedwave in pipe wall to calculate the pipe wall thickness; the basic theory and wave equation ofultrasonic guided waves are studied and analyzed, the waveform conversion does not occurwhen SH guided wave reflects and transmits as a source at the interface and measurements, anddesign a wave guide rod with high signal to noise ratio and good heat dissipation according tothe propagation characteristics of wave. Second, select the periodic pulse signal modulated byHanning Window function as acoustic excitation source, the SH wave energy attenuation degree,the stability of wave shape and other propagation characteristics in the wave guide rod aresimulated and analyzed by using the finite element method, verify the correctness andrationality of the source wave and the wave guide rod design, optimize and select the bestworking parameters. Third, design and select the data processing, data transmission, datamanagement systems and other auxiliary systems, is selected as the system control unit, andselect ATmega128microcontroller，ultrasonic transmitting/receiving circuit, counting circuit, and the wireless communication module based on ZigBee transmission; wireless network basedon ZigBee transmission is established through the router and coordinator to achievelong-distance transmission of thickness data; using the LabWindows/CVI softwaredevelopment platform and Microsoft Access database, develop a data processing software torend the wall thickness thinning curve, and alarm the extreme thickness and the rate ofthickness reduction. The wall thickness on-line monitoring management system for hightemperature pipe in this research can achieve the pipelines’ real-time and fixed-point on-linethickness measurement, and the thickness data is transmitted to the control room through thewireless network. The thickness data were visualized by data processing software, make up theshortcomings of the existing monitoring technology, solve the problem of high temperaturepipeline monitoring local failure. The system is innovative and has high application value.