In-situ monitoring of transient gas phase K–Cl–S chemistry in a pilot-scale combustor

2020 ◽  
Author(s):  
Jan Viljanen ◽  
Thomas Allgurén ◽  
Yueming Wang ◽  
Xiaolong Li ◽  
Juha Toivonen ◽  
...  
Keyword(s):  
Gas Phase ◽  
Pilot Scale ◽  
In Situ Monitoring

Online sensing of volatile organic compounds in groundwater using mid-infrared fibre optic evanescent wave spectroscopy: a pilot scale test

2003 ◽  
Vol 47 (2) ◽  
pp. 121-126 ◽  
Author(s):  
H. Steiner ◽  
K. Staubmann ◽  
R. Allabashi ◽  
N. Fleischmann ◽  
A. Katzir ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Pilot Plant ◽  
Pilot Scale ◽  
In Situ Monitoring ◽  
Fibre Optic ◽  
Sensor Head ◽  
Sensing System ◽  
Volatile Organic

A prototype sensing system for in-situ monitoring of volatile organic compounds in contaminated groundwater was tested at a pilot scale plant. The sensor consists of a commercially available Fourier transform infrared spectrometer, connected to a 6 m long infrared transparent silver halide fibre optic cable. A 10 cm long core-only section at the centre of the fibre is mounted on a sensor head and coated with a hydrophobic polymer layer, while the remaining fibre is protected by Teflon tubing and thus not in contact with the surrounding media. The sensor head was immersed into the monitoring wells of the pilot plant testing the sensor system under circumstances close to field conditions and typical for in-situ measurements. The pilot plant consists of a 1 m3 cubic tank filled with gravel. A pump is used to circulate water horizontally through the tank, simulating a natural aquifer. The evolution of the concentration of analytes injected into the system is monitored with time using the developed prototype sensing system. The results are validated by corresponding sampling and analysis with headspace gas chromatography.

In situ monitoring and control of multicomponent gas-phase streams for growth of GaN via MOCVD

2000 ◽  
Vol 212 (1-2) ◽  
pp. 11-20 ◽  
Author(s):  
M.C Johnson ◽  
K Poochinda ◽  
N.L Ricker ◽  
J.W Rogers Jr ◽  
T.P Pearsall
Keyword(s):  
Gas Phase ◽  
In Situ Monitoring ◽  
Monitoring And Control ◽  
Multicomponent Gas ◽  
And Control

scholarly journals Sequential Collinear Photofragmentation and Atomic Absorption Spectroscopy for Online Laser Monitoring of Triatomic Metal Species

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 533 ◽  
Author(s):  
Jan Viljanen ◽  
Kim Kalmankoski ◽  
Victor Contreras ◽  
Jaakko K. Sarin ◽  
Tapio Sorvajärvi ◽  
...  
Keyword(s):  
Atomic Absorption ◽  
Gas Phase ◽  
Absorption Spectroscopy ◽  
Atomic Absorption Spectroscopy ◽  
Limit Of Detection ◽  
In Situ Monitoring ◽  
Metal Species ◽  
Chemical Reaction Kinetics

Industrial chemical processes are struggling with adverse effects, such as corrosion and deposition, caused by gaseous alkali and heavy metal species. Mitigation of these problems requires novel monitoring concepts that provide information on gas-phase chemistry. However, selective optical online monitoring of the most problematic diatomic and triatomic species is challenging due to overlapping spectral features. In this work, a selective, all-optical, in situ gas-phase monitoring technique for triatomic molecules containing metallic atoms was developed and demonstrated with detection of PbCl2. Sequential collinear photofragmentation and atomic absorption spectroscopy (CPFAAS) enables determination of the triatomic PbCl2 concentration through detection of released Pb atoms after two consecutive photofragmentation processes. Absorption cross-sections of PbCl2, PbCl, and Pb were determined experimentally in a laboratory-scale reactor to enable calibration-free quantitative determination of the precursor molecule concentration in an arbitrary environment. Limit of detection for PbCl2 in the laboratory reactor was determined to be 0.25 ppm. Furthermore, the method was introduced for in situ monitoring of PbCl2 concentration in a 120 MWth power plant using demolition wood as its main fuel. In addition to industrial applications, the method can provide information on chemical reaction kinetics of the intermediate species that can be utilized in reaction simulations.

Application of FT-IR Absorption Spectroscopy for in Situ Gas Concentration and Temperature Measurements in Laboratory- and Pilot-Scale Combustion Environments

1993 ◽  
Vol 47 (11) ◽  
pp. 1898-1906 ◽  
Author(s):  
Denise M. Martin ◽  
Patrick J. Medvecz ◽  
Kenneth M. Nichols
Keyword(s):  
Gas Phase ◽  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Diagnostic Tool ◽  
Heterogeneous Reaction ◽  
Black Liquor ◽  
Pilot Scale ◽  
Ir Absorption ◽  
Ft Ir

In situ FT-IR absorption spectroscopy was used as a diagnostic tool to evaluate the gas phase above a heterogeneous reaction, black liquor char combustion. Previously developed calculation methodologies were used to determine the CO and CO2 concentrations and the CO rotational temperatures from absorption spectra. Spectroscopically obtained gas temperatures and concentrations from laboratory-scale experiments were compared to thermocouple and NDIR measurements. Quantitative evaluations of the gas phase during these experiments indicated that gas temperatures can be measured with an accuracy of 2–3% at 450–750 K and gas concentrations can be measured with accuracies of better than 10% at gas concentrations between 0.3 and 1.3%. Gas temperatures obtained during pilot-scale combustion were between 1118 and 1183 K, while concentrations were between 0.35 and 0.76%. Differences among gas concentrations and temperatures calculated from the absorption spectra, compared to NDIR measurements and thermocouples, were greater than those from laboratory combustion due to the dynamics of the gas phase. The need is exemplified for a well-characterized combustion environment for effective use of FT-IR as a diagnostic tool for pilot-scale combustion and for advancing the fundamental understanding of combustion processes.

In-Situ Spectroscopic Ellipsometry Applied to ZnSe and ZnCdSe Growth Process in Organometallic Vapor Phase Epitaxy

1992 ◽  
Vol 242 ◽  
Author(s):  
J. Iacoponi ◽  
L. B. Bhat ◽  
B. Johs ◽  
J.A. Woollam
Keyword(s):  
Film Thickness ◽  
Gas Phase ◽  
Vapor Phase ◽  
Spectroscopic Ellipsometry ◽  
Growth Process ◽  
Vapor Phase Epitaxy ◽  
In Situ Monitoring ◽  
Semiconductor Materials ◽  
Organometallic Vapor Phase Epitaxy

ABSTRACTSpectroscopie ellipsometry is a well developed technique for studying the semiconductor materials and heterostructures. Here, we have applied this technique to in-situ studies of ZnSe and ZnCdSe growth in a low pressure organometallic vapor phase epitaxy system. The growth of ZnSe on GaAs was studied using a light source in the range 2 to 4 eV, and film thickness of a few tens of angstroms could be monitored by this technique. The band gap and the composition of Zn1-χCdχSe could also be measured as a function of real time. It was found that, for a gas phase DMCd composition of 60%, the amount of Cd incorporated in the layers is less than 25%. Spectroscopie ellipsometry is demonstrated to be a valuable technique for in-situ monitoring of semiconductor growth in organometallic vapor phase epitaxy systems.

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