Detection of potentially explosive methane levels using a solid-state infrared source

Leis, John and Buttsworth, David and Snook, Chris and Holmes, Graham (2014) Detection of potentially explosive methane levels using a solid-state infrared source. IEEE Transactions on Instrumentation and Measurement, 63 (12). pp. 3088-3095. ISSN 0018-9456

Abstract

Detection of methane gas which may be approaching the concentration limit when explosive ignition could occur is an important industrial problem. Optical methods for gas detection are attractive, and near-infrared (IR) wavelengths are especially suited to the detection of hydrocarbon gases. Unfortunately, temperature-related drift of solid-state IR sources is problematic. A method for stabilizing the response of a near-IR solid-state gas detection system operating at 2350 nm is presented in this paper. The system employs a broadband LED source and a wideband photodetector. Because IR absorption in the gas cell is used as an indirect measure of gas concentration, it is necessary to stabilize the optical source power. We approach this problem by employing a novel two-frequency pulsed excitation method. Stable measurements suitable for detecting the presence of methane gas at a concentration of 50% of the lower explosive limit are experimentally demonstrated. The response of the system is validated against the HITRAN IR spectroscopy database, by incorporating the emitter and detector IR profiles.
Good agreement between the derived gas concentration and theoretical predictions based on standard gas absorption models is demonstrated for 2.5% methane in air, which is a critical point for determining the presence of potentially explosive mixtures.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to published version due to publisher copyright policy.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 13 Dec 2014 23:42
Last Modified: 06 Feb 2018 01:46
Uncontrolled Keywords: gas leak detection; infrared (IR) spectroscopy; natural gas; signal processing; synchronous detection
Fields of Research : 09 Engineering > 0906 Electrical and Electronic Engineering > 090606 Photonics and Electro-Optical Engineering (excl. Communications)
09 Engineering > 0906 Electrical and Electronic Engineering > 090603 Industrial Electronics
09 Engineering > 0906 Electrical and Electronic Engineering > 090609 Signal Processing
Socio-Economic Objective: B Economic Development > 86 Manufacturing > 8615 Instrumentation > 861501 Industrial Instruments
B Economic Development > 86 Manufacturing > 8615 Instrumentation > 861503 Scientific Instruments
Identification Number or DOI: 10.1109/TIM.2014.2327457
URI: http://eprints.usq.edu.au/id/eprint/26361

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