绝缘/带绝缘包覆油气管道多电极电容分层直接成像无损检测技术研究

Insulating/insulated pipes are widely used in petrochemical and oil/gas transportation industries due to their corrosion-resistive and thermal insulating nature. However, various types of defects and anomalies within the pipes will significantly affect their performance. It is thus important to carry out effective Non-destructive Evaluation to detect such defects. This project proposes a novel multi-electrode capacitive direct imaging technique with stratified imaging layers (Referred to as multi-electrode capacitive imaging technique). The research involves: to investigate the distribution of the quasi-static probing field within the specimen and its distortion pattern due to defects; to clarify the relationship between the targeted defect and the resultant capacitive image; to investigate the optimized design principles for the multi-electrode probe; to develop and verify defect information acquisition scheme, namely reconstruction for each layer followed by analysis and combination, based on the measurement sensitivity distribution; to build an optimized multi-electrode capacitive imaging system to verified the theory and improve its technology readiness by testing standard specimen with artificial defects and real pipes. This proposed technique is capable of detecting defects within the pipe wall and wax deposition inside the pipe for insulating pipes and defects within the insulation layer and corrosion under insulation for insulated pipes. This project aims to bridge the gap between theoretical analysis of this novel multi-electrode capacitive imaging approach and its applications towards insulating/insulated pipes. The technique will through time become a focus for applied research, thereby providing solutions for some real and difficult problems in industry.

绝缘/带绝缘包覆金属管因其良好的防腐保温性，被广泛应用于石化、储运等行业，而各类缺陷及异常对其性能影响显著，实现绝缘/带绝缘包覆油气管中不同类型缺陷的有效检出是当前的热点问题。本项目拟研究一种多电极电容分层直接成像无损检测技术：探究多电极电容探头准静电探测场的分布特征及不同类型缺陷对其作用机理；明确被测区域中缺陷信息与成像结果关联规律；研究多电极电容探头性能优化方法及设计参数选取策略；设计并验证基于检测灵敏度分布的先逐层反演后分析合成的缺陷信息获取方案；构建并优化多电极电容分层直接成像检测系统，利用对含人工缺陷试件和实际管道试件的试验检测，验证理论成果并提高技术实用性。该技术可实现绝缘管管壁缺陷、管内积蜡及带绝缘包覆管绝缘层层中缺陷及层下腐蚀等各类缺陷的检测与识别。项目的顺利实施，可丰富无损检测学科的内容，为保障绝缘/带绝缘包覆石油管的安全运行提供一种新的无损检测方法。

绝缘/带绝缘包覆金属管因其良好的防腐保温性，被广泛应用于石化、储运等行业，而各类缺陷及异常对其性能影响显著，实现绝缘/带绝缘包覆油气管中不同类型缺陷的有效检出是当前的热点问题。本项目重点研究了多电极电容分层直接成像无损检测技术及将其应用于缘/带绝缘包覆金属管时所需解决的关键问题：探明了电容探头准静电探测场的分布特征及不同类型缺陷对其作用机理；明确了被测区域中缺陷信息与成像结果关联规律；研究了多电极电容探头性能优化方法及设计参数选取策略；设计并验证了基于检测灵敏度分布的的先逐层反演后分析合成的缺陷信息获取方案；构建并优化了多电极电容分层直接成像检测系统。研究结果表明，该技术可实现绝缘管管壁缺陷、管内积蜡及带绝缘包覆管绝缘层层中缺陷及层下腐蚀等各类缺陷的检测与识别。项目的顺利实施，丰富了电磁无损检测学科的内容，为保障绝缘/带绝缘包覆石油管的安全运行提供一种新的无损检测方法。