Pipeline Leakage And Corrosion Detection Based On FBG Hoop Strain Sensor

With the rapid development of pipeline transport in various fields, the safe operation of the Oil and Gas Pipeline is increasingly significant. Regular testing can not meet the security requirements of pipelines, so nondestructive real-time monitoring of oil and gas pipelines becomes a hot direction of research. For special necessity against fire and explosion, anti-electromagnetic interference requirements of oil and gas transportation, combined with grating fiber optic technology witch has advantages such as high sensitivity to strain and temperature, tolerance of harsh circumstance, flexible packaging method. In this paper, a pipeline health monitoring method based on the fiber Bragg grating hoop strain sensors is presented.The layout of the paper is as follows:The first chapter is introduction, this part presents an overview of the development process of China’s pipeline transportation and future trends, a review of domestic and international pipeline major catastrophic accidents due to explosion and leakage. Health monitoring of pipelines under operations is highlight the importance. Secondly, lists the advantages and deficiencies of pipeline leakage and corrosion monitoring research achievements and the existing detection techniques. Focuses on the progress in the application of optical fiber sensing technology to monitor the pipeline, working principle and performance advantages of fiber grating sensors, concludes with this study and research directions.The second chapter content for design of the fiber Bragg grating strain sensors which can measure strain on the whole cross section. Firstly, sensors design background and works on sensitizing the theoretical derivation of the sensor is introduced, and especially for the shape of the pipe wall deformation, effective coating and installation techniques is developed. In order to ensure that the sensors on site in effective stress state, a controllable pretension system is designed. Sensitizing effect of different sensor performance tests are performed. The experiment proved that the hoop strain sensors have a certain sensitizing effect, analyzed the relationship between theory and experiment sensitization coefficient values;an in-depth study of the sensor under large strain and small strain response of cases is conducted, by adjusting the ratio of internal components we can meet the needs of different diameters of structures.The third chapter introduces the gas pipeline leak detection experiments,in which the FBG hoop strain sensors are used. The purpose of the experiment is to verify the ability of the hoop strain sensor to monitor the pipeline leak signal timely and accurately. Experimental results show that the sensor is capable of detecting the pipeline leak, leakage of different positions, different conditions for pattern recognition.The fourth chapter describes gas pipeline corrosion monitoring experiments in which the fiber Bragg grating hoop strain sensors are used. Different pipe wall thickness is designed in the experiment system to simulate different degree of corrosion. Experiments show that this FBG hoop strain sensor can react to changes in the wall thickness of the pipe, so as to achieve the purpose of monitoring pipeline corrosion with engineering applications.