scholarly journals Simultaneous Quantitative Detection of HCN and C2H2 in Combustion Environment Using TDLAS

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2033
Author(s):  
Wubin Weng ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Laminar Flame ◽  
Tunable Diode Laser ◽  
Quantitative Detection ◽  
Temperature Dependent ◽  
Soot Particles ◽  
Laser Absorption ◽  
Hot Gas ◽  
Diode Laser Absorption ◽  
Combustion Environment

Emission of nitrogen oxides (NOx) and soot particles during the combustion of biomass fuels and municipal solid waste is a major environmental issue. Hydrogen cyanide (HCN) and acetylene (C2H2) are important precursors of NOx and soot particles, respectively. In the current work, infrared tunable diode laser absorption spectroscopy (IR-TDLAS), as a non-intrusive in situ technique, was applied to quantitatively measure HCN and C2H2 in a combustion environment. The P(11e) line of the first overtone vibrational band v1 of HCN at 6484.78 cm−1 and the P(27e) line of the v1 + v3 combination band of C2H2 at 6484.03 cm−1 were selected. However, the infrared absorption of the ubiquitous water vapor in the combustion environment brings great uncertainty to the measurement. To obtain accurate temperature-dependent water spectra between 6483.8 and 6485.8 cm−1, a homogenous hot gas environment with controllable temperatures varying from 1100 to 1950 K provided by a laminar flame was employed to perform systematic IR-TDLAS measurements. By fitting the obtained water spectra, water interference to the HCN and C2H2 measurement was sufficiently mitigated and the concentrations of HCN and C2H2 were obtained. The technique was applied to simultaneously measure the temporally resolved release of HCN and C2H2 over burning nylon 66 strips in a hot oxidizing environment of 1790 K.

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

2022 ◽  
pp. 000370282110608
Author(s):  
Wubin Weng ◽  
Jim Larsson ◽  
Joakim Bood ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Diode Laser ◽  
Hydrogen Chloride ◽  
Absorption Spectroscopy ◽  
Flue Gas ◽  
Hot Water ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Temperature Dependent ◽  
Laser Absorption ◽  
Diode Laser Absorption

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.

CO Concentration Measurement in the High Temperature Flame With Tunable Diode Laser Absorption Spectroscopy

2011 ◽  
Author(s):  
Ting Xu ◽  
Fei Wang ◽  
Zhishen Jiang ◽  
Jianhua Yan ◽  
Kefa Cen ◽  
...  
Keyword(s):  
High Temperature ◽  
Diode Laser ◽  
Absorption Spectroscopy ◽  
Equivalence Ratio ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Co Concentration ◽  
Diode Laser Absorption ◽  
Combustion Environment

CO concentration real-time monitoring in combustion process has great significance in improving combustion efficiency and controlling combustion emissions. No CO-spectroscopy solid state sensors are available at the high temperature of 1600K–2000K in the flames. Gas sensing based on tunable diode laser absorption spectroscopy (TDLAS) with the advantages of high sensitivity, high selectivity, quick response and non-intrusiveness offers the possibility for on-line measurement in combustion environment. CO absorption line located at 2302.12nm is selected for measurement by direct absorption method in premixed C3H8/Air flat flame. Experiment results show that, when equivalence ratio is larger than one, the concentration of CO in the flame is increased with the increase of equivalence ratio. It proves that this method can be used on combustion environment.

Gaseous Contaminant Measurement for Semiconductor Processing by Diode Laser Spectroscopy

1995 ◽  
Vol 38 (5) ◽  
pp. 22-29
Author(s):  
James McAndrew ◽  
Ronald Inman ◽  
Benjamin Jurcik
Keyword(s):  
Diode Laser ◽  
Fluid Dynamic ◽  
Air Separation ◽  
Tunable Diode Laser ◽  
Laser Absorption ◽  
Diode Laser Spectroscopy ◽  
Diode Laser Absorption ◽  
Gaseous Contaminant

Tunable diode laser absorption spectroscopy (TDLAS) is a novel tool for purity measurement in microelectronic process gases and environments. It is compatible with any matrix gas and extremely sensitive. This paper describes the application of a laboratory TDLAS instrument to measurement of CO, CO2, and H2O with sub-ppb sensitivity, including determination of a CO level of 0.35± 0.2 ppb in nitrogen samples from an air separation plant. Fluid dynamic simulation was used to optimize the design of the cell used for H20 measurements. TDLAS lends itself to the study of contamination sources in situ. As examples, measurements of CO generation in sampling vessels and of CO2 outgassing in an electropolished stainless steel chamber are briefly discussed.

scholarly journals Measurement of Temperature and H2O Concentration in Premixed CH4/Air Flame Using Two Partially Overlapped H2O Absorption Signals in the Near Infrared Region

2021 ◽  
Vol 11 (8) ◽  
pp. 3701
Author(s):  
Sunghyun So ◽  
Nakwon Jeong ◽  
Aran Song ◽  
Jungho Hwang ◽  
Daehae Kim ◽  
...  
Keyword(s):  
Diode Laser ◽  
Absorption Spectroscopy ◽  
High Speed ◽  
Equivalence Ratio ◽  
Tunable Diode Laser ◽  
Laser Absorption Spectroscopy ◽  
Laser Absorption ◽  
Voigt Fitting ◽  
Diode Laser Absorption ◽  
Combustion Environment

It is important to monitor the temperature and H2O concentration in a large combustion environment in order to improve combustion (and thermal) efficiency and reduce harmful combustion emissions. However, it is difficult to simultaneously measure both internal temperature and gas concentration in a large combustion system because of the harsh environment with rapid flow. In regard, tunable diode laser absorption spectroscopy, which has the advantages of non-intrusive, high-speed response, and in situ measurement, is highly attractive for measuring the concentration of a specific gas species in the combustion environment. In this study, two partially overlapped H2O absorption signals were used in the tunable diode laser absorption spectroscopy (TDLAS) to measure the temperature and H2O concentration in a premixed CH4/air flame due to the wide selection of wavelengths with high temperature sensitivity and advantages where high frequency modulation can be applied. The wavelength regions of the two partially overlapped H2O absorptions were 1.3492 and 1.34927 μm. The measured signals separated the multi-peak Voigt fitting. As a result, the temperature measured by TDLAS based on multi-peak Voigt fitting in the premixed CH4/air flame was the highest at 1385.80 K for an equivalence ratio of 1.00. It also showed a similarity to those tendencies to the temperature measured by the corrected R-type T/C. In addition, the H2O concentrations measured by TDLAS based on the total integrated absorbance area for various equivalent ratios were consistent with those calculated by the chemical equilibrium simulation. Additionally, the H2O concentration measured at an equivalence ratio of 1.15 was the highest at 18.92%.

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