Research On Detection Method Of Residual Wall Thickness Of Process Pipeline Corrosion In Oil And Gas Gathering And Transportation Station

Oil and gas gathering and transportation station includes metering station,oil transfer station,dehydration station and so on,as an important oil transportation hub,a large amount of crude oil is processed every day.While,the crude oil contains a variety of corrosive liquids and corrosive gas composition,and the erosion and corrosion of the corrosive mixed liquid on the pipe wall of the field are the main causes of the failure of the pipeline.Pulsed Eddy Current Testing Technology has been widely used in the field of nondestructive testing because of its wide spectrum,strong penetrating power,without coupling agent and fast online detection.In this paper,the pulsed eddy current testing technology is studied aim at the thinning of the tube wall caused by corrosion.The main work are completed as follows:(1)This paper introduced the basic principle of Traditional Eddy Current Testing,which mainly involves skin effect and impedance analysis;analyzed the Pulsed Eddy Current Testing Technology according to the circuit transition theory and basic theory of pulsed eddy current;analyzed the theory of Pulsed Eddy Current Testing Technology from the aspect of circuit and deducing the model of the voltage and the phase.(2)In this paper,the finite element model formula of pulse eddy current testing was derived.The author employed the Multi physics finite element simulation software-COMSOL to make a simulation study of detecting system.After optimizing the parameters such as the coil turns and the excitation frequency by simulation,the author made a further study of the influence of fluid in pipeline on detection results.(3)This paper designed the overall experimental scheme of the detection system,including excitation power,square wave exciting circuit,sensor coil,signal processing circuit,data acquisition card,software design,etc.Then designed the square wave conditioning circuit,sensor coil,signal processing circuit particularly and software.(4)This paper carried out the group experiment based on the COMSOL model simulation,experiment system and hardware design,including the detection of the thickness of pipe wall without liquid and with different fluids such as water and mixed liquid.The experimental results show that the pulsed eddy current nondestructive testing technology has a good effect on the detection of residual wall thickness of the oil pipeline when there is liquid or not,and has high sensitivity and good reliability.