New sensor sniffs out gas leaks
21 May 2002
Successful early tests of a pipeline sensor that locates plastic, ceramic and metallic underground pipes could help reduce dangerous instances of natural gas pipeline breaks.
The US Department of Energy is working with the Gas Technology Institute (GTI) to develop the prototype sensor which, if all goes as planned, should be ready for demonstration by the end of this year.
The sensor resembles a flat plate made of electrodes. When placed on the ground, the sensor uses low-frequency electrical waves to detect buried ceramic, plastic and metallic objects.
The GTI sensor would reportedly address long-standing problems that have impeded the industry's efforts to detect non-metallic distribution lines, which are buried anywhere from 3 to 10 feet deep. In a recent test, the sensor imaged a four-inch plastic pipe beneath four feet of soil.
Competing sensors that use high-frequency waves are more expensive and not as effective because soil more easily absorbs high-frequency waves. High frequencies formed the backbone of detection systems used by the military and mining industry because they produce clearer images of metal objects.
Borrowing components from these existing sensors, GTI's low-frequency technique is enhanced by multiple antennas that sharpen an image's resolution without the high costs associated with electronics that support high-frequency sensors.
The low-frequency technique also detects non-metallic objects, a capability that most other sensors don't have.
The gas distribution industry is said to have needed such a tool for decades. While not a common occurrence, so-called 'third-party damage' is the single main reason for pipeline damage.
Demand for natural gas in the United States is projected to expand faster than any other fuel source during the next two decades, largely because more power companies are using natural gas to generate electricity.
The National Petroleum Council, an advisory committee to the US Secretary of Energy, recently forecasted the need for more than 38,000 miles of new gas transmission lines and 263,000 miles of distribution mains by 2015.
Increasingly, plastic and ceramic materials are being used in newer gas distribution pipes. The GTI estimates that 72 percent of all 3-inch-diameter natural gas distribution pipes in the US are plastic.
