基于双环电阻传感器的管道内壁腐蚀监测技术研究

Study of the Pipeline Inner Corrosion Monitoring Technique Based on Ring Pair Electrical Resistance Sensor

为实现管道内壁腐蚀的全周向在线监测并提高测量精度,在传统电阻法的基础上提出一种基于双环电阻探针的腐蚀监测方法。双环电阻探针解决了由于几何限制和管道内外壁温差所带来的测量误差。通过对双环探针进行多象限分区,求解各分区的电阻比值,实现了管道全方位的在线腐蚀监测。通过双环探针可以同时实现对管道内外壁的温差计算与实时监测,为湿蒸汽管道冷凝液膜的形成起到预报作用。基于以上研究基础,在实验室X65模拟管路中,分别布置四象限分区双环电阻传感器、传统丝状电阻传感器和高精度热电偶对管道的腐蚀和内外壁温差进行实时监测。试验结果表明:基于新型双环探针的管道内壁腐蚀监测方法,可以完成管道内外壁温差和局部分区腐蚀状态的在线监测,并在腐蚀深度和腐蚀速率的测量上比传统丝状电阻探针具有更高的监测精度。

To realize the pipeline whole circumference inner corrosion on-line monitoring and promote the measurement accuracy, a new method based on the traditional electrical resistance（ER） approach is developed for corrosion monitoring on account of the new type ring pair ER probe. The measuring error produced by the geometry restriction and temperature difference can be solved through the ring pair probe. Through the set of multi segments on the circumference of the ring pair and the calculation of resistance ratio of each segment, the pipeline whole direct on-line corrosion monitoring is realized. The temperature difference between the inner pipe wall and outer pipe wall can also be calculated and monitored through the ring pair method. The formation of the condensate liquid film in the vapor transportation pipeline can be forecasted. Based on the research, a four quadrants ring pair sensor, traditional wire ER sensor and high accuracy thermocouples are arranged into the X65 pipeline which is placed in the laboratory to monitor the pipeline inner corrosion and the temperature difference between the inner and outer pipe wall. The results shows that the method which uses the new type ring pair ER probe can measure the temperature difference between the inner and outer pipe wall. And through the comparison with the corrosion coupon, it is found that the ring pair ER sensor had high measurement accuracy on the corrosion depth and corrosion rate than the traditional wire ER sensor.