Characterization of a fast gas analyzer based on Raman scattering for the analysis of synthesis gas

Eichmann, S. C.; Weschta, Martin; Kiefer, Johannes; Seeger, Thomas; Leipertz, Alfred

doi:10.1063/1.3521397

Cited by 45 publications

(34 citation statements)

References 26 publications

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“…Related information to spectral soft modeling can be found elsewhere. [2,4,[33][34][35][36] The used contour-fit algorithm determines the relative species concentration in volume percent fully automatically. For the quantitative gas analysis with the evaluation technique described here, three main conditions must be fulfilled within the operating range of the sensor system:…”

Section: Data Evaluation and Calibration Proceduresmentioning

confidence: 99%

Demonstration of a signal enhanced fast Raman sensor for multi‐species gas analyses at a low pressure range for anesthesia monitoring

Schlüter

Krischke

Popovska-Leipertz³

et al. 2015

J Raman Spectroscopy

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The spontaneous Raman scattering technique is an excellent tool for a quantitative analysis of multi-species gas mixtures. It is a noninvasive optical method for species identification and gas phase concentration measurement of Raman active molecules, since the intensity of the molecule specific Raman signal is linearly dependent on the concentration. Applying a continuous wave (cw) laser it typically takes a few seconds to capture a gas phase Raman spectrum at room temperature. Nevertheless in contrast to these advantages the weak Raman signal intensity is a major drawback. Thus, it is still challenging to detect gas phase Raman spectra in a low-pressure regime with a temporal resolution of only a few 100 ms. In the presented study a fully functional gas phase Raman system for measurements in the low-pressure regime (p ≥ 980 hPa (absolute)) is presented; it overcomes the drawback of the weak Raman effect by using a multipass cavity to enhance the Raman signal. The signal amplification of a retroreflecting cavity is experimentally compared to a near-confocal cavity. A description of this sensor setup as well as of the calibration procedure, which also allows the quantification of condensable gases, is presented. Moreover the functionality of the sensor system is demonstrated in a measurement campaign at an anesthesia simulator under clinical relevant conditions and in comparison to a conventional gas monitor.

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Section: Data Evaluation and Calibration Proceduresmentioning

confidence: 99%

Demonstration of a signal enhanced fast Raman sensor for multi‐species gas analyses at a low pressure range for anesthesia monitoring

Schlüter

Krischke

Popovska-Leipertz³

et al. 2015

J Raman Spectroscopy

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“…Two further much weaker bands at 812 cm −1 and 1032 cm −1 were also observed (see Figure S1 in the supplementary information), corresponding to the transitions S 0 (2) (J = 2 → 4) and S 0 (3) (J = 3 → 5) respectively. 25,36 Higher rotational levels were not observed because these levels are not significantly populated at room temperature. 3,36 From the spectrum of the evacuated tube it can be seen that sampling through the glass wall of the NMR tube does not complicate the spectrum in this region, except with a broad glass signal which can be easily removed with baseline correction (see Figure S1 for examples of nonbaseline correct spectra).…”

Section: Raman Spectra Of Hydrogen Gasmentioning

confidence: 99%

“…25,36 Higher rotational levels were not observed because these levels are not significantly populated at room temperature. 3,36 From the spectrum of the evacuated tube it can be seen that sampling through the glass wall of the NMR tube does not complicate the spectrum in this region, except with a broad glass signal which can be easily removed with baseline correction (see Figure S1 for examples of nonbaseline correct spectra). As expected, the spectrum from the pH 2 enriched sample had a much greater proportion of signal from the rotational band corresponding to the pH 2 isomer, compared to the spectrum from the nH 2 sample.…”

Section: Raman Spectra Of Hydrogen Gasmentioning

confidence: 99%

Quantitative In Situ Monitoring of Parahydrogen Fraction Using Raman Spectroscopy

Parrott

Dallin²,

Andrews³

et al. 2018

Appl Spectrosc

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Raman spectroscopy has been used to provide a rapid, non-invasive and non-destructive quantification method for determining the parahydrogen fraction of hydrogen gas. The basis of the method is the measurement of the ratio of the first two rotational bands of hydrogen at 355 cm −1 and 586 cm −1 corresponding to parahydrogen and orthohydrogen, respectively. The method has been used to determine the parahydrogen content during a production process and a reaction. In the first example, the performance of an in-house liquid nitrogen cooled parahydrogen generator was monitored both at-line and on-line. The Raman measurements showed that it took several hours for the generator to reach steady state and hence, for maximum parahydrogen production (50 %) to be reached. The results obtained using Raman spectroscopy were compared to those obtained by at-line low-field NMR spectroscopy. While the results were in good agreement, Raman analysis has several advantages over NMR for this application. The Raman method does not require a reference sample, as both spin isomers (ortho and para) of hydrogen can be directly detected, which simplifies the procedure and eliminates some sources of error. In the second example, the method was used to monitor the fast conversion of parahydrogen to orthohydrogen in-situ. Here the ability to acquire Raman spectra every 30 s enabled a conversion process with a rate constant of 27.4 × 10 −4 s −1 to be monitored. The Raman method described here represents an improvement on previously reported work, in that it can be easily applied on-line and is approximately 500 times faster. This offers the potential of an industrially compatible method for determining parahydrogen content in applications that require the storage and usage of hydrogen.

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“…For syngas containing carbon monoxide, this range would need to be extended to ~2300 cm −1 , which is possible in a straightforward manner. Eichmann et al [68] substituted carbon monoxide by carbon dioxide for safety reasons, as CO is a highly toxic substance and can be harmful even at low concentration [69]. Therefore, syngas applications require high safety standards and gas leakage must be detected as early as possible; hence the need for highly sensitive analytical methods.…”

Section: Alternative Gaseous Fuels and Special Applicationsmentioning

confidence: 99%

“…For example, synthesis gas (also known as syngas), which represents mixtures mainly comprising of carbon monoxide and hydrogen, were analyzed by Raman techniques. Eichmann et al [68] carried out a systematic investigation of the pressure and temperature influence on the Raman spectra of carbon dioxide/hydrogen mixtures in order to develop an approach for determining the composition of syngas. Moreover, they discussed the suitability of different spectral ranges used for data evaluation and concluded that the fingerprint region from 300 to 1600 cm −1 provides the best accuracy.…”

Section: Alternative Gaseous Fuels and Special Applicationsmentioning

confidence: 99%

Recent Advances in the Characterization of Gaseous and Liquid Fuels by Vibrational Spectroscopy

Kiefer

2015

Energies

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Most commercial gaseous and liquid fuels are mixtures of multiple chemical compounds. In recent years, these mixtures became even more complicated when the suppliers started to admix biofuels into the petrochemical basic fuels. As the properties of such mixtures can vary with composition, there is a need for reliable analytical technologies in order to ensure stable operation of devices such as internal combustion engines and gas turbines. Vibrational spectroscopic methods have proved their suitability for fuel characterization. Moreover, they have the potential to overcome existing limitations of established technologies, because they are fast and accurate, and they do not require sampling; hence they can be deployed as inline sensors. This article reviews the recent advances of vibrational spectroscopy in terms of infrared absorption (IR) and Raman spectroscopy in the context of fuel characterization. The focus of the paper lies on gaseous and liquid fuels, which are dominant in the transportation sector and in the distributed generation of power. On top of an introduction to the physical principles and review of the literature, the techniques are critically discussed and compared with each other.

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Characterization of a fast gas analyzer based on Raman scattering for the analysis of synthesis gas

Cited by 45 publications

References 26 publications

Demonstration of a signal enhanced fast Raman sensor for multi‐species gas analyses at a low pressure range for anesthesia monitoring

Demonstration of a signal enhanced fast Raman sensor for multi‐species gas analyses at a low pressure range for anesthesia monitoring

Quantitative In Situ Monitoring of Parahydrogen Fraction Using Raman Spectroscopy

Recent Advances in the Characterization of Gaseous and Liquid Fuels by Vibrational Spectroscopy

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