Detection Professional Blog
Technology Used By The Natural Gas Industry
Today’s natural gas industry faces constant pressure to improve worker and public safety as well as reduce methane emissions to improve the environment. SENSIT Technologies continues to lead the way, bringing solutions to the marketplace that address both issues.
Every natural gas company’s most critical mission is the protection of life and property. There are many new technologies and products being introduced that can help the industry effectively, efficiently, and affordably meet that mission. This article will discuss the tools used for various activities conducted by natural gas workers: 1) detectors for responding to odor and gas leak investigations, 2) devices and technology used for leak surveys and methane specific detection, and 3) new, emerging technologies for data collection and remote and unmanned detection.
When a natural gas worker is conducting a leak investigation, it is important to realize the situation usually begins as an odor complaint, but not necessarily a natural gas leak. All responding personnel should carry devices capable of detecting a wide variety of combustible gasses. The worker does not know what they might encounter so broad-spectrum detection is important. Gas detection products using semiconductor sensors are widely accepted because of their ability to detect small concentrations (less than 5 percent by volume) of a variety of combustibles combined with their durability, cost, and stability. Other detection products may use catalytic style sensors though they do not have sensitivity in the low part-per-million range often required to find the smaller leak sources.
Higher concentrations of gas are typically measured with infrared or thermal conductivity sensors. These sensors allow for the measurement of gas across the full range of concentrations, from a few percent to 100% by volume. Conversely, semiconductor or catalytic sensors cannot measure high concentrations on their own. Typically, manufacturers must combine two technologies to cover the full range, transitioning from semiconductor or catalytic to thermal conductive sensors.
Another critical operation for every natural gas company is the periodic survey of their entire piping system, both above and below ground. These system-wide leak surveys are conducted to ensure the integrity of the gas network. The gas operator is looking exclusively for low levels of methane that may be escaping the piping system. Instruments that utilize Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology are popular for leak surveys since they are methane selective with no cross sensitivity to other gases.
Detectors utilizing TDLAS technology take two general forms.
First are open path detectors. In an open path detector, laser light is emitted from a hand-held device across an area. The laser bounces back to the detector and the amount of reflected light is measured. If the laser encounters methane along its path, some proportional amount of the light is absorbed, creating a reading. This reading is not the actual volume concentration, but rather an indication of the presence of methane. If quantification of the emission is desired, another instrument must be used. A number of these devices are on the market, some including GPS readings. Note that the GPS coordinates usually reflect where the person is standing, not necessarily where the location of the methane emission. Some new devices can supplement the GPS reading with distance, direction and angle of detection, making the GPS data more useful and precise.
The second kind of detector utilizing TDLAS measures methane across a fixed path length. These methane detectors are usually portable and incorporate a sample pump and a laser array configured inside the instrument. These devices measure methane from low (single digit ppm or less) concentrations through the highest volumes (100% gas). Note that, contrary to the open path detector, these will be actual concentrations that can be used for safety and classification purposes. In both cases, the laser detector is methane specific and will not measure any other gases found in natural gas nor other gases that may pe present in the survey area.
New products and software solutions are in development today that will assist in recordkeeping of leak events and offer real-time remote monitoring. For example managers could monitor a first responder or surveyor’s detector through an app or remote connection, allowing improved situational awareness for both workers and management. Resources can be deployed or repositioned to best meet the demands of the event. All records of the event are captured for later reference.
SENSIT Technologies has been designing and producing instruments for the Natural Gas industry for more than 40 years. The deployment of new and improved technologies has never been faster nor the times more exciting to keep our people and environment safer, healthier, and cleaner every day.