Passive Open-Path FTIR Measurements and Spectral Interpretations for in situ Gas Monitoring and Process Diagnostics
S. Cięszczyk
Institute of Electronics and Information Technology, Lublin University of Technology, Nadbystrzycka 38A, 20-618 Lublin, Poland
Received: May 7, 2014; In final form: July 2, 2014
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This article aims to present the possibilities for the passive spectral measurements and qualitative interpretations of inside-the-object gases. The basic features and applications of open-path Fourier transform infrared spectroscopy for measuring atmospheric and process exhaust gases are discussed. Methods for modelling and interpreting the spectra used for in situ measurements are presented. As an example, a spectrum simulation was investigated using CO2, a gas present in substantial quantities in various exhaust gases. The spectrum varied significantly with temperature allowing its use for diagnostics purposes. Thus, examples of measurements made using passive transmission with a heated object as a radiation source are presented. A baseline correction procedure was necessary to obtain a transmission (or absorbance) spectrum. The gas content and temperature were determined based on these measurements.

DOI: 10.12693/APhysPolA.126.673
PACS numbers: 07.07.Df, 07.57.Ty, 33.20.Ea, 07.05.Tp