Abstract

An instrument was developed for the detection of NH₃ in flue gas, exploiting a fortuitous spectral overlap between the ν₂aQ(6,6) absorption line of NH₃ and the R (18) emission line of the isotopic ¹³C¹⁶O₂ laser. The system was developed for use with De–NO_x processes, which convert harmful nitric oxides generated in utility and industrial furnaces into harmless nitrogen and water vapor by injection of NH₃. The instrument detects unreacted NH₃ in the flue gas down to concentrations of a few ppm with an accuracy of ∼10%. It can serve as an environmental monitor and as part of a feedback control system to adjust the upstream NH₃ injection to the desired rate.

© 1983 Optical Society of America

Laser Stark spectrometer for the measurement of ammonia in flue gas

Adriaan J. L. Verhage, Rudy A. Rooth, and Leo W. Wouters
Appl. Opt. 32(30) 5856-5866 (1993)

Measurements of NH₃ absorption coefficients with a C¹³O₂¹⁶ laser

Frank Allario and R. K. Seals
Appl. Opt. 14(9) 2229-2233 (1975)

Ammonia monitoring near 1.5 µm with diode-laser absorption sensors

Michael E. Webber, Douglas S. Baer, and Ronald K. Hanson
Appl. Opt. 40(12) 2031-2042 (2001)

CO₂ Laser Absorption Coefficients for Determining Ambient Levels of O₃, NH₃, and C₂H₄

R. R. Patty, G. M. Russwurm, W. A. McClenny, and D. R. Morgan
Appl. Opt. 13(12) 2850-2854 (1974)

Pulsed laser optoacoustic detection of flame species

Gregory P. Smith, Mark J. Dyer, and David R. Crosley
Appl. Opt. 22(24) 3995-4003 (1983)