Stack Gas Pollutant Detection Using Laser Raman Spectroscopy
Abstract:An experimental system to investigate the feasibility of using laser Raman spectroscopy to detect stack gas pollutants is described. With spontaneous Raman spectroscopy, one unit is capable of measuring all gas species simultaneously and, when applied to a continuous emissions monitoring (CEM) system, could both simplify it and improve reliability. Minimum detectabilities with the use of this weak light scattering process were determined for the three primary pollutants from coal-based power plants: carbon monoxide (CO), sulfur dioxide (SO2), and nitric oxide (NO). A frequency-doubled, pulsed Nd:YAG laser was used to excite the test gas held in a sample cell. A charge-coupled device connected to a spectrometer was used as the detection system, providing complete spectral information. A set of experiments was carried out for different concentrations of the three test gas species. With a 200-s integration time, the following minimum detectability limits were obtained: 100 ppm for SO , 250 ppm for CO, and 250 ppm for NO. A mixture of all three pollutants in a base of N2 was made to simulate typical stack gas mixtures. Baseline strength and associated shot noise are more severe when gas mixtures are being analyzed. One possible explanation is the broad-band fluorescence of NO2 , perhaps produced pho2 tolytically. System modifications to improve minimum detectabilities are discussed.
Document Type: Research Article
Publication date: June 1, 1997
More about this publication?
- The Society publishes the internationally recognized, peer reviewed journal, Applied Spectroscopy, which is available both in print and online. Subscriptions are included with membership or can be purchased by institutional or corporate organizations. Abstracts may be viewed free of charge. Previously published as Bulletin (Society for Applied Spectroscopy)
- Editorial Board
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Request copyrighted SAS materials
- Spectroscopic Nomenclature
- Focal Point (Open Access)
- ingentaconnect is not responsible for the content or availability of external websites