The hydrocarbon leak detector developed by Sandia is currently being tested at petroleum refineries in California, Texas, and the United Kingdom. Data show that the hydrocarbon imager is a promising alternative to the laborious gas leak detection technique currently mandated by the Environmental Protection Agency.
Two Methods of Optical Imaging
There are two methods of optical imaging used for leak detection, passive imaging and active imaging.
Passive Imaging
Current devices use a video camera with a filter that depends on light coming from the scene. The sensitivity of this system is subject to ambient conditions, such as temperature and the amount of light at the scene.
Active Imaging
Sandia’s system uses fiber laser input for illumination, which allows the device to operate independently of ambient conditions. Commercial systems use CO2 lasers, which unfortunately cannot illuminate several of the primary gases of interest to the industry, such as methane or other hydrocarbons.
Sandia has developed two portable imagers: a hydrocarbon leak detector for use in petroleum refineries and a natural gas (methane) imaging system. Both systems use a technique called backscatter absorption gas imaging (BAGI) to illuminate a scene with infrared (IR) laser radiation. Target gases present in the scene absorb the laser light, creating dark clouds in the video image of an IR camera. The portable imager makes a gas plume visible to an operator via a real time video picture. The instrument rapidly scans a two-dimensional area, accelerating the gas survey procedure.
This technology has the potential to reduce costs, minimize gas lost to leaks, and improve safety in the gas industry. The portable gas imager is suitable for a variety of operational scenarios. A handheld device also offers greater flexibility in detecting gas leaks in tight places—where vehicle-mounted instruments are impossible to use—in homes and commercial facilities, for viewing hard-to-access locations during distribution leak surveys (such as over-the-fence access), including leak detection in production facilities (e.g., natural gas compressor stations), and for leak detection during excavation activities.
Future areas of development for Sandia’s portable imagers include measuring gas concentration to a high degree of specificity, using alternative laser sources, and reducing the detection threshold. Our targeted partners and customers are in the petroleum and petrochemical industries.