Infrared absorption spectrometer for the determination of temperature and species profiles in an entrained flow gasifier

Nau, Patrick; Kutne, Peter; Eckel, Georg; Meier, Wolfgang; Hotz, Christian; Fleck, Sabine

doi:10.1364/ao.56.002982

Cited by 11 publications

(3 citation statements)

References 23 publications

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“…Figure 2 summarizes some representative results from a number of sensor development and implementation studies in terms of detection limits and bandwidths. It compares species concentration measurements in a variety of combustion systems including laboratory environments [1,[16][17][18][19][20][21][22], shock tube studies [23][24][25][26][27][28], industry processes [29][30][31][32][33], and engines [34][35][36][37][38][39][40][41][42][43][44][45][46]. For the purpose of making a direct comparison between different studies, the reported absolute minimal detection limits for several commonly probed species in combustion, including CO, CO 2 , H 2 O, and C 2 H 2 , are plotted on the same diagram against detection bandwidths.…”

Section: Sensor Design Targets and Measurement Challengesmentioning

confidence: 99%

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Wang

Chao

2019

Applied Sciences

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Laser absorption spectroscopy (LAS) is a promising diagnostic method capable of providing high-bandwidth, species-specific sensing, and highly quantitative measurements. This review aims at providing general guidelines from the perspective of LAS sensor system design for realizing quantitative species diagnostics in combustion-related environments. A brief overview of representative detection limits and bandwidths achieved in different measurement scenarios is first provided to understand measurement needs and identify design targets. Different measurement schemes including direct absorption spectroscopy (DAS), wavelength modulation spectroscopy (WMS), and their variations are discussed and compared in terms of advantages and limitations. Based on the analysis of the major sources of noise including electronic, optical, and environmental noises, strategies of noise reduction and design optimization are categorized and compared. This addresses various means of laser control parameter optimization and data processing algorithms such as baseline extraction, in situ laser characterization, and wavelet analysis. There is still a large gap between the current sensor capabilities and the demands of combustion and engine diagnostic research. This calls for a profound understanding of the underlying fundamentals of a LAS sensing system in terms of optics, spectroscopy, and signal processing.

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Section: Sensor Design Targets and Measurement Challengesmentioning

confidence: 99%

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Wang

Chao

2019

Applied Sciences

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“…Lackner et al [6] monitored C 2 H 4 with mid-infrared (MIR) absorption in biogas at 1 atm in a room temperature cell. Recently, Nau et al used MIR to monitor CO, CH 4 , and H 2 O in a two-stage gasifier similar to the one used here for biomass [7]. Diode laser absorption sensing was used to detect HCl emissions in producer gas from biomass gasification [8].…”

Section: Measurement Science and Technologymentioning

confidence: 99%

Design and implementation of a laser-based absorption spectroscopy sensor for in situ monitoring of biomass gasification

Salazar¹,

Goldenstein²,

Jeffries³

et al. 2017

Meas. Sci. Technol.

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Research to demonstrate in situ laser-absorption-based sensing of H2O, CH4, CO2, and CO mole fraction is reported for the product gas line of a biomass gasifier. Spectral simulations were used to select candidate sensor wavelengths that optimize sensitive monitoring of the target species while minimizing interference from other species in the gas stream. A prototype sensor was constructed and measurements performed in the laboratory at Stanford to validate performance. Field measurements then were demonstrated in a pilot scale biomass gasifier at West Biofuels in Woodland, CA. The performance of a prototype sensor was compared for two sensor strategies: wavelength-scanned direct absorption (DA) and wavelength-scanned wavelength modulation spectroscopy (WMS). The lasers used had markedly different wavelength tuning response to injection current, and modern distributed feedback lasers (DFB) with nearly linear tuning response to injection current were shown to be superior, leading to guidelines for laser selection for sensor fabrication. Non-absorption loss in the transmitted laser intensity from particulate scattering and window fouling encouraged the use of normalized WMS measurement schemes. The complications of using normalized WMS for relatively large values of absorbance and its mitigation are discussed. A method for reducing adverse sensor performance effects of a time-varying WMS background signal is also presented. The laser absorption sensor provided measurements with the sub-second time resolution needed for gasifier control and more importantly provided precise measurements of H2O in the gasification products, which can be problematic for the typical gas chromatography sensors used by industry.

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“…Nau et al [ 19 ] also used simultaneously a DFB (2.3 µm) and an IC laser (3.1 µm) in a fiber-based absorption spectrometer to measure temperature and concentrations of CO, CH 4 , C 2 H 2 , and H 2 O in an entrained flow gasifier. A wavelength division multiplexing approach using a single ZrF 4 fiber was used to measure both wavelength regions simultaneously.…”

Section: Introductionmentioning

confidence: 99%

A Compact Fiber-Coupled NIR/MIR Laser Absorption Instrument for the Simultaneous Measurement of Gas-Phase Temperature and CO, CO2, and H2O Concentration

Shi

Endres

Jeffries

et al. 2022

Sensors

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A fiber-coupled, compact, remotely operated laser absorption instrument is developed for CO, CO2, and H2O measurements in reactive flows at the elevated temperatures and pressures expected in gas turbine combustor test rigs with target pressures from 1–25 bar and temperatures of up to 2000 K. The optical engineering for solutions of the significant challenges from the ambient acoustic noise (~120 dB) and ambient test rig temperatures (60 °C) are discussed in detail. The sensor delivers wavelength-multiplexed light in a single optical fiber from a set of solid-state lasers ranging from diodes in the near-infrared (~1300 nm) to quantum cascade lasers in the mid-infrared (~4900 nm). Wavelength-multiplexing systems using a single optical fiber have not previously spanned such a wide range of laser wavelengths. Gas temperature is inferred from the ratio of two water vapor transitions. Here, the design of the sensor, the optical engineering required for simultaneous fiber delivery of a wide range of laser wavelengths on a single optical line-of-sight, the engineering required for sensor survival in the harsh ambient environment, and laboratory testing of sensor performance in the exhaust gas of a flat flame burner are presented.

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Infrared absorption spectrometer for the determination of temperature and species profiles in an entrained flow gasifier

Cited by 11 publications

References 23 publications

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Laser Absorption Sensing Systems: Challenges, Modeling, and Design Optimization

Design and implementation of a laser-based absorption spectroscopy sensor for in situ monitoring of biomass gasification

A Compact Fiber-Coupled NIR/MIR Laser Absorption Instrument for the Simultaneous Measurement of Gas-Phase Temperature and CO, CO2, and H2O Concentration

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