Ammonia sensing system based on wavelength modulation spectroscopy

A sensing system in the near infrared region has been developed for ammonia sensing based on the wavelength modulation spectroscopy (WMS) principle. The WMS is a rather sensitive technique for detecting atomic/molecular species, presenting the advantage that it can be used in the near-infrared region by using the optical telecommunications technology. In this technique, the laser wavelength and intensity were modulated by applying a sine wave signal through the injection current, which allowed the shift of the detection bandwidth to higher frequencies where laser intensity noise was typically lower. Two multi-pass cells based on free space light propagation with 160 cm and 16 cm of optical path length were used, allowing the redundancy operation and technology validation. This system used a diode laser with an emission wavelength at 1512.21 nm, where NH3 has a strong absorption line. The control of the NH3 gas sensing system, as well as acquisition, processing and data presentation was performed.

[1]  Zoltán Bozóki,et al.  Ammonia monitoring at ppb level using photoacoustic spectroscopy for environmental application , 2008 .

[2]  A. Berg,et al.  Ammonia sensors and their applications - a review , 2005 .

[3]  Hal Westberg,et al.  Measurement of atmospheric ammonia at a dairy using differential optical absorption spectroscopy in the mid-ultraviolet , 2002 .

[4]  R. Tatam,et al.  Optical gas sensing: a review , 2012 .

[5]  Barbara A. Paldus,et al.  High-sensitivity detectors based on cavity ring-down spectroscopy , 2004, SPIE Security + Defence.

[6]  Luc Thévenaz,et al.  Ammonia trace measurements at ppb level based on near-IR photoacoustic spectroscopy , 2006 .

[7]  A. O’Keefe,et al.  Cavity ring‐down optical spectrometer for absorption measurements using pulsed laser sources , 1988 .

[8]  L. Hodson,et al.  Field comparison of methods for the measurement of gaseous and particulate contributors to acidic dry deposition. , 1990 .

[9]  Guido Busca,et al.  Chemical and mechanistic aspects of the selective catalytic reduction of NOx by ammonia over oxide catalysts: A review , 1998 .

[10]  András Miklós,et al.  Detection of ammonia by photoacoustic spectroscopy with semiconductor lasers. , 2002, Applied optics.

[11]  Luc Thévenaz,et al.  Ammonia monitoring at trace level using photoacoustic spectroscopy in industrial and environmental applications. , 2004, Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy.

[12]  L R Narasimhan,et al.  Correlation of breath ammonia with blood urea nitrogen and creatinine during hemodialysis , 2001, Proceedings of the National Academy of Sciences of the United States of America.

[13]  Grzegorz Fusiek,et al.  Temperature characterisation of an optically interrogated Rogowski coil , 2014, Other Conferences.

[14]  Luc Thévenaz,et al.  Wavelength modulation spectroscopy: combined frequency and intensity laser modulation. , 2003, Applied optics.

[15]  Martin Ferm,et al.  Method for determination of atmospheric ammonia , 1979 .

[16]  J. B. Paul,et al.  Sensitive absorption measurements in the near-infrared region using off-axis integrated-cavity-output spectroscopy , 2002 .

[17]  M. Shelef,et al.  Development of a Method for the Analysis of NO2 and NH3 by NO-Measuring Instruments , 1973 .

[18]  R. A. Perez-Herrera,et al.  Fiber optic sensing system for monitoring of coal waste piles in combustion , 2014, Other Conferences.

[19]  Volker Thomsen,et al.  Limits of Detection in Spectroscopy , 2003 .

[20]  D. Leleux,et al.  Ammonia Detection by use of Near-Infrared Diode-Laser-Based Overtone Spectroscopy. , 2001, Applied optics.

[21]  Gregory J Fetzer,et al.  Tunable diode laser absorption spectroscopy in coiled hollow optical waveguides. , 2002, Applied optics.

[22]  D. Griffith,et al.  Measurements of ammonia emissions from spreading of manure using gradient FTIR techniques , 2000 .

[23]  G. P. Wyers,et al.  A continuous-flow denuder for the measurement of ambient concentrations and surface-exchange fluxes of ammonia , 1993 .

[24]  M. Keuken,et al.  The determination of ammonia in ambient air by an automated thermodenuder system , 1989 .