Methodology for detection of carbon monoxide in hot, humid media by telecommunication distributed feedback laser-based tunable diode laser absorption spectrometry

Abstract

Detection of carbon monoxide (CO) in combustion gases by tunable diode laser spectrometry is often hampered by spectral interferences from H2O and CO2. A methodology for assessment of CO in hot, humid media using telecommunication distributed feedback lasers is presented. By addressing the R14 line at 6395.4 cm(-1), and by using a dual-species-fitting technique that incorporates the fitting of both a previously measured water background reference spectrum and a 2f-wavelength modulation lineshape function, percent-level concentrations of CO can be detected in media with tens of percent of water (c(H2O)≤40%) at T≤1000 °C with an accuracy of a few percent by the use of a single reference water spectrum for background correction.

Co Sensor with High Concentrations of H₂O at Elevated Temperature by TDLAS

“…The spectral interferences of CO detection from water at the elevated temperature.To illustrate the temperature dependence of spectral interferences from H 2 O on detection of CO, the R14 transition was investigated experimentally for a variety of temperatures. The present calculations reveal that at low temperatures (≤200 °C) the line is virtually unaffected by the presence of water, and that there is a little spectral interference from 200 to 400°C [9].But it is sustainable for field application when the 2f-wm-signal is fitted by a nonlinear least-squares fitting algorithm (Levenberg-Marquardt) to the individual second-harmonic absorption profiles which called the directed-fitting-technique. Many sensors for detection of CO have been demonstrated using this technique at low temperature [7,[10][11][12].…”

Application of Multiple Line Integrated Spectroscopy on CO Concentration Measurement

“…A selection of the analysed wavelengths in spectroscopic measurements is depended on a few factors, such as absorption spectrum of the given gas, optoelectronic elements availability of the desired spectral characteristics as well as absorption spectra of each gas in the mixture. Measurement selectivity requires that within the wavelengths analysed, the other substances should have no absorption lines or of negligible amplitudes [3], [4], [11].…”

“…Optoelectronic sensors are commonly used in various everyday applications, especially in technology. For the sake of their response time, high selectivity, resistance to harsh weather conditions as well as long operating time, optoelectronic sensors tends to supersede conventional catalytic and electrochemical sensors [1]- [3]. One of significant field of application is power engineering, where they are applied both for controlling of fuel mixture composition and flue gas monitoring.…”

“…One of significant field of application is power engineering, where they are applied both for controlling of fuel mixture composition and flue gas monitoring. Such sensors can be also applied for measurement of atmosphere composition inside a power boiler [3]- [7] so as e.g. to estimate the threat of low-oxygen corrosion [8].…”

“…The operation of the vast majority of optoelectronic sensors is based on absorption spectroscopy, thus it utilizes measurement of light transmission within a particular wavelength range. Nowadays, most of the interest has been focused on the sensors that operate within spectral ranges that are applied in optical fibre communication [3], [7]. It is commonly known that within the considered wavelength ranges, most of the measured substances reveal comparatively weak light absorption, yet their application seems to be promising taking their both attractive price and quality into consideration.…”