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Open AccessArticle

LED-Absorption-QEPAS Sensor for Biogas Plants

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Fraunhofer Heinrich Hertz Institute
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Clausthal University of Technology, IEPT, Am Stollen 19B, Goslar 38640, Germany
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Clausthal University of Technology, EFZN, Am Stollen 19A, Goslar 38640, Germany
*
Author to whom correspondence should be addressed.
Academic Editor: Vittorio M.N. Passaro
Sensors 2015, 15(5), 12092-12102; https://doi.org/10.3390/s150512092
Received: 20 March 2015 / Accepted: 13 May 2015 / Published: 22 May 2015
(This article belongs to the Section Physical Sensors)
A new sensor for methane and carbon dioxide concentration measurements in biogas plants is presented. LEDs in the mid infrared spectral region are implemented as low cost light source. The combination of quartz-enhanced photoacoustic spectroscopy with an absorption path leads to a sensor setup suitable for the harsh application environment. The sensor system contains an electronics unit and the two gas sensors; it was designed to work as standalone device and was tested in a biogas plant for several weeks. Gas concentration dependent measurements show a precision better than 1% in a range between 40% and 60% target gas concentration for both sensors. Concentration dependent measurements with different background gases show a considerable decrease in cross sensitivity against the major components of biogas in direct comparison to common absorption based sensors. View Full-Text
Keywords: optical sensing; spectroscopy; photoacoustic; absorption; biogas optical sensing; spectroscopy; photoacoustic; absorption; biogas
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MDPI and ACS Style

Köhring, M.; Böttger, S.; Willer, U.; Schade, W. LED-Absorption-QEPAS Sensor for Biogas Plants. Sensors 2015, 15, 12092-12102.

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