New Sensor Could Help Avert Pipeline Failures

Oct 03, 2008

(PhysOrg.com) -- Researchers at the National Institute of Standards and Technology (NIST) and Colorado School of Mines (CSM) have developed a prototype sensor that quickly detects very small amounts of hydrogen accumulation in coated pipeline steel. The new sensor could provide early warning of pipes that have accumulated excessive amounts of hydrogen -- a notorious source of embrittlement—and avert potentially disastrous failures of pipelines carrying hydrogen fuel.

Hydrogen is attractive as a fuel because it burns cleanly without carbon emissions and can be derived from domestic sources. However one long-recognized challenge is that hydrogen can cause gradual embrittlement in conventional pipelines by slowly diffusing into the metal. The NIST/CSM sensor, described today at the 7th International Pipeline Conference,* could monitor for hydrogen buildup before a pipeline actually fails in service, or during testing or production.

The nondestructive, non-contact hydrogen sensor is approximately 4 square inches and is designed to be a portable sensor to make measurements on excavated or unexcavated pipeline steels. The sensor sends a current through the pipe and measures changes in impedance (resistance with a function of depth) as an indicator of hydrogen content within the steel and the overall steel pipe integrity. The hydrogen sensor is based on electromagnetic concepts to generate alternating currents into the pipeline steel, which in turn induces an opposing magnetic field. Any change in the hydrogen content in the steel modifies the current, resistivity, and thus the impedance.

NIST laboratory and field test results show that a pipe’s impedance, and thus resistivity, increases with increasing hydrogen content. The measurement sensitivity is exceptional: the sensor can measure hydrogen content levels in pipeline steel well below 1 part per million (ppm). High strength pipeline steels can tolerate only a few parts per million of hydrogen before significant problems arise. By contrast, conventional analytical techniques do not have sensitivity or accuracy below 1 ppm. The new hydrogen sensor also acts as a forewarning or preventative monitoring system to detect the agents that actually cause the flaws, cracks and defects before they arise. Most traditional nondestructive tools used in the pipeline industry (such as ultrasonics and magnetic flux leakage) are used for determination of cracks, corrosion or other flaws that have already occurred.

The sensor development was supported in part by the Minerals Management Service and Department of Transportation.

Citation: A. Lasseigne, K. Koenig, J. Jackson, D. Olson, B. Mishra, T.A. Siewert and J.D. McColskey. Advanced non-destructive hydrogen sensors to prevent material degradation from hydrogen damage. Paper presented Oct. 1 at IPC2008, 7th International Pipeline Conference, Sept. 29 – Oct. 3, 2008, Calgary, Alberta, Canada.

Provided by NIST

Explore further: Razor-sharp TV pictures

add to favorites email to friend print save as pdf

Related Stories

New gas sensors for monitoring carbon dioxide sinks

May 08, 2008

A novel gas sensor system makes it possible to monitor large areas cost-effectively the first time. The patented gas sensor is based on the principle of diffusion, according to which certain gases pass through ...

Full-time sensors can detect bridge defects

Aug 07, 2007

Networks of small, permanently mounted sensors could soon check continuously for the formation of structural defects in I-beams and other critical structural supports of bridges and highway overpasses, giving ...

Recommended for you

Razor-sharp TV pictures

1 hour ago

The future of movie, sports and concert broadcasting lies in 4K definition, which will bring cinema quality TV viewing into people's homes. 4K Ultra HD has four times as many pixels as today's Full HD. And ...

Michigan team finds security flaws in traffic lights

2 hours ago

What if attackers could manipulate traffic lights so that accidents would happen with mayhem as the result? That is a question many would rather put off for another day but authorities feeling responsible ...

Virtual reality guides those whose memory is failing

23 hours ago

Experts agree that the ability to navigate a neighborhood or built space is one of the first faculties to suffer at the onset of cognitive decline. They also agree that early intervention is crucial for stemming ...

User comments : 0