<title>Localization of methane distributions by spectrally tuned infrared imaging</title>

Abstract

We present a novel method, the Gas Imaging (GIm) method, developed for the localization of gas distributions in the atmosphere. The method is suitable for the detection of gases which exhibit at least one absorption line in the infrared spectral range. In this paper the Gim method is demonstrated for methane released into the atmosphere from leaks along natural gas pipelines. Methane distributions in the atmosphere around the leaky pipeline are detected and visualized by spectrally tuned infrared imaging. In contrast to conventional techniques which utilize laser radiation sources or scanning, we irradiate the overall region under investigation by 1 kW halogen lamps. The scene background is subtracted by a realtime computer evaluation ofthe image. The methane gas emitted from the leak creates a flickering cloud in the image which is easily recognized. Methane concentrations as low as 0.03 % by volume (cloud diameter 30 cm) are visible. The method was successftilly tested under realistic conditions on a buried pipeline by a natural gas provider.

Dispersion modeling approach for quantification of methane emission rates from natural gas fugitive leaks detected by infrared imaging technique

“…A cloud with a diameter of 30 cm was observed and a methane concentration as low as 0.03% can be detected. During the test, the gas flow rate was gradually decreased, and a gas mass flow rate as low as 0.1 L/min could still be recognized (Gross et al, 1998). A similar camera system had been applied to detect and monitor methane leaks from pipelines under realistic condition by Schulz et al The infrared optical imaging was used to monitor leaks from a natural gas pipeline buried 1.2 m underground.…”

Mobile Laser-Absorption Imaging System for Detection of Natural Gas Leaks

“…Several other systems have been built to detect natural or atmospheric gases. [6][7][8][9][10][11] The instrument was designed and fabricated to provide natural gas utilities with a reliable, cost effective means of locating leaks. The use of a 2-dimensional imaging lidar was employed so that many (64) simultaneous measurements could be made.…”