DOI QR코드

DOI QR Code

Feasibility Study on the Utilization of EMAT Technology for In-line Inspection of Gas Pipeline

  • 투고 : 2010.08.25
  • 심사 : 2010.11.24
  • 발행 : 2011.03.31

초록

If gas is leaking out of gas pipelines, it could cause a huge explosion. Accordingly, it is important to ensure the integrity of gas pipelines. Traditionally, over the years, gas-operating companies have used the ILI system, which is based on axial magnetic flux leakage (MFL), to inspect the gas pipelines. Relatively, there is a low probability of detection (POD) for the axial defects with the axial MFL-based ILI. To prevent the buried pipeline from corrosion, it requires a protective coating. In addition to the potential damage to the coating by environmental factors and external forces, there could be defects on the damaged coating area. Thus, it is essential that nondestructive evaluation methods for detecting axial defects (axial cracks, axial groove) and damaged coating be developed. In this study, an electromagnetic acoustic transducer (EMAT) sensor was designed and fabricated for detecting axial defects and coating disbondment. In order to validate the performances of the developed EMAT sensor, experiments were performed with specimens from axial cracks, axial grooves, and coating disbondment. The experimental results showed that the developed EMAT sensor could detect not only the axial cracks (minimum 5% depth of wall thickness) and axial grooves (minimum 10% depth of wall thickness), but also the coating disbondment.

키워드

참고문헌

  1. J. Aron, J. Gore et al., Development of an EMAT In-Line Inspection System for Detection, Discrimination, and Grading of Stress Corrosion Cracking in Pipelines, Annual Technical Progress Report, Tuboscope Pipeline Services (2001) pp. 11-12.
  2. Thomas Beuker and Joerg Damaschke, In-line Inspection with High Resolution EMAT Technology Crack Detection and Coating Disbondment, Rosen Technology & Research Center, 20th international Pipeline Pigging, IntegrityAssessment & Repair Conference (2008).
  3. M. Hirao and H. Ogi, EMATs for Science and Industry - Nondestructive Ultrasonic Measurements, Kluwer Academic Publishers, Boston (2003) pp. 73-75.
  4. R. B. Thompson, Measurements with EMAT Transducer, Physical Acoustics Vol.XIX, Academic Press, Burlington, MA (1990) pp. 192-196.
  5. J. L. Rose, Ultrasonic Waves in Solid Media, Cambridge University Press, Cambridge (2000) pp. 101-113.