Detection of HCl on the first and second overtone using semiconductor diode lasers at 1.7 μm and 1.2 μm

Corsi, C.; Inguscio, M.; Chudzyński, S.; Ernst, K.; D’Amato, Francesco; Rosa, M. De

doi:10.1007/s003400050616

Cited by 14 publications

(9 citation statements)

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“…In order to address these issues and to derive good estimates for possible systematic deviations caused by these problems as described above, we propose the use of approximate, assumed BL properties in realistic application scenarios in combination with a dTDLAS-instrument with a full physical model and complete set of spectral parameters for the target absorption line. In addition to our previous case studies (Qu et al 2018) for CO 2 -dTDLAS and CO-dTDLAS, this work focuses on a new 3.6 µm mid-IR HCl 1 3 spectrometer which has a better sensitivity compared to the previous 1.74 µm HCl-TDLAS systems (Ortwein et al 2010;Bjoroey et al 1996;Masusaki et al 1999;Corsi et al 1999). The transition line strength of the probed HCl absorption line at 3.6 µm is more than ten times stronger than the lines in the NIR range.…”

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confidence: 96%

Towards a dTDLAS-Based Spectrometer for Absolute HCl Measurements in Combustion Flue Gases and a Better Evaluation of Thermal Boundary Layer Effects

Nwaboh

Werhahn

et al. 2020

Flow Turbulence Combust

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This work presents a mid-IR direct tunable diode laser absorption spectroscopy (dTDLAS)-based HCl spectrometer, which is specially designed and optimized to measure HCl concentration in combustion exhaust gas matrices (i.e. elevated gas temperatures, high water vapour and CO2 contents). The work is motivated by (legal) requirements for monitoring combustion emissions from large-scale power stations or biomass burning domestic boilers. In our novel dTDLAS HCl spectrometer we use a low power room temperature mid-IR ICL diode laser to access the HCl P5 line at 2775.76 cm−1 in the 1-0 vibrational band which was especially selected for gas matrixes with high CO2 and H2O admixtures. With this set-up we demonstrate at 77 cm path length, total pressure from 320 hPa to 954 hPa, room temperature and at 110 s of signal averaging an optimal precision of 0.17 µmol/mol (ppm). Gas monitoring in combustion applications and elevated gas temperatures are prone to systematic errors caused by spectroscopic falsifications in colder gas boundary layers (BL) unavoidable in the high temperature gas ducts. These BL lead, e.g. to temperature, matrix composition or target gas concentration gradients near walls, which also influence the spectroscopic raw signal via their temperature and collision partner dependence. Depending on the chosen spectral line these can cause significant systematic deviations in in-situ, line-of-sight (LOS) laser spectrometers. For an improved understanding of the quantitative effects of thermal BL on our LOS HCl dTDLAS spectrometer and better representing real BL, we expanded our spectroscopic BL simulation model to allow for continuous (linear) instead of the previous stepwise changes. From the new simulation results, we deduce systematic relative deviations in the extracted HCl-concentration to be up to 10% depending on the magnitude of the BL changes and the choice of the “representative” single temperature measurement. With this simulation model, a user can now derive the system’s systematic deviation based on assumptions on the present temperature gradients. The model also helps the user to choose the gas temperature measurement location in his process, in order to minimize the spatial heterogeneity effects.

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confidence: 96%

Towards a dTDLAS-Based Spectrometer for Absolute HCl Measurements in Combustion Flue Gases and a Better Evaluation of Thermal Boundary Layer Effects

Nwaboh

Werhahn

et al. 2020

Flow Turbulence Combust

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“…Qu et al 5 and Nwaboh et al 6 developed HCl measurement using TDLAS probing the fundamental vibrational band. Linnerud et al, 7 Corsi et al, 8 Kim et al, 9 and Ortwein et al 10 used the overtone vibrational band of HCl, mostly the first overtone. The rotational lines of the first overtone at around 1.7 μm were regarded as a very suitable choice, whereas the second overtone has much weaker line intensity 8 and the fundamental band requires more expensive equipment.…”

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confidence: 99%

Quantitative Hydrogen Chloride Detection in Combustion Environments Using Tunable Diode Laser Absorption Spectroscopy with Comprehensive Investigation of Hot Water Interference

et al. 2022

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Hydrogen chloride (HCl) monitoring during combustion/gasification of biomass fuels and municipal solid waste, such as polyvinyl chloride (PVC) and food residues, is demanded to avoid the adverse effect of HCl to furnace operation and to improve the quality of the gas products. Infrared tunable diode laser absorption spectroscopy (IR-TDLAS) is a feasible nonintrusive in-situ method for HCl measurements in harsh environments. In the present work, the measurement was performed using the R(3) line of the ν2 vibrational band of HCl at 5739.25 cm–1 (1742.4 nm). Water vapor is ubiquitous in combustion/gasification environments, and its spectral interference is one of the most common challenges for IR-TDLAS. Spectral analysis based on the current well-known databases was found to be insufficient to achieve an accurate measurement. The lack of accurate temperature-dependent water spectra can introduce thousands parts per million (ppm) HCl overestimation. For the first time, accurate spectroscopic data of temperature-dependent water spectra near 5739.3 cm–1 were obtained based on a systematic experimental investigation of the hot water lines in a well-controlled, hot flue gas with a temperature varying from 1100 to 1950 K. With the accurate knowledge of hot water interference, the HCl TDLAS system can achieve a detection limit of about 100 ppm⋅m at around 1500 K, and simultaneously the gas temperature can be derived. The technique was applied to measure the temporally resolved HCl release and local temperature over burning PVC particles in hot flue gas at 1790 K.

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“…19,–21 There have also been several fundamental studies on the infrared absorption spectroscopy of HCl and the use of TDLs for in situ measurement of this gas in various applications. 22,–37 Although some of the prior studies have investigated gas temperatures of up to 1000 °C, 34 none have considered HCl concentrations approaching 95% at high temperature.…”

Section: Introductionmentioning

confidence: 99%

Optical Absorption Measurements of Hydrogen Chloride at High Temperature and High Concentration in the Presence of Water Using a Tunable Diode Laser System for Application in Pyrohydrolysis Non-Ferrous Industrial Process Control

et al. 2015

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A tunable diode laser (TDL) was used to measure hydrogen chloride (HCl) spectra at 5747 cm(-1) (1.74 μm) and temperatures of 25-950 °C in a quartz cell. The purpose was to evaluate the capability of monitoring HCl concentration under pyrohydrolysis conditions using a near-infrared (NIR) laser. These conditions are characterized by 20-40% HCl, 2-40% H2O, and the presence of metal chloride vapors at temperatures of 600-1000 °C. Spectral peak area measurements of HCl-N2 mixtures at atmospheric pressure and a path length of 8.1 cm showed linear absorption behavior between concentrations of 5-95% and temperatures of 25-950 °C. Results from the addition of 2-40% water (H2O) indicate that the HCl peak area relationships are not affected for temperatures of 350-950 °C. Evaporating NiCl2 within the cell did not show spectral interference effects with HCl between 650 and 850 °C. The results from this work indicate that a near-infrared optical sensor is capable of measuring high HCl concentrations at high temperatures in the presence of high H2O content during pyrohydrolysis process conditions.

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Detection of HCl on the first and second overtone using semiconductor diode lasers at 1.7 μm and 1.2 μm

Cited by 14 publications

References 0 publications

Towards a dTDLAS-Based Spectrometer for Absolute HCl Measurements in Combustion Flue Gases and a Better Evaluation of Thermal Boundary Layer Effects

Towards a dTDLAS-Based Spectrometer for Absolute HCl Measurements in Combustion Flue Gases and a Better Evaluation of Thermal Boundary Layer Effects

Quantitative Hydrogen Chloride Detection in Combustion Environments Using Tunable Diode Laser Absorption Spectroscopy with Comprehensive Investigation of Hot Water Interference

Optical Absorption Measurements of Hydrogen Chloride at High Temperature and High Concentration in the Presence of Water Using a Tunable Diode Laser System for Application in Pyrohydrolysis Non-Ferrous Industrial Process Control

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