Laser-based detection of methane and soot during entrained-flow biomass gasification

Sepman, Alexey; Thorin, Emil; Ögren, Yngve; Ma, Charlie; Carlborg, Markus; Wennebro, Jonas; Broström, Markus; Wiinikka, Henrik; Schmidt, Florian M.

doi:10.1016/j.combustflame.2021.111886

Cited by 16 publications

(5 citation statements)

References 47 publications

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“…Prior to the gasification experiments, the reactor was first preheated by oil combustion until the inner ceramic lining of the reactor reached 1200 K and then by biomass combustion up to a temperature of 1250 K. 35 In situ laser diagnostics was conducted in the reactor core through optical access ports located 1.7 and 2.15 m downstream of the fuel inlet. Gas temperature and H 2 O concentration were measured at both ports using TDLAS systems operating at 1.4 m, 51 , 52 and K species concentrations were measured at the upper port using a PF-TDLAS system. 33 − 35 The PF-TDLAS system ( Figure 1 a) consisted of a tunable diode laser emitting around 770 nm (probe laser) and ns-pulsed Nd:YAG lasers at 266 and 355 nm (pump lasers).…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…The boundary conditions in the simulations are set according to the experimental conditions during the gasification of FR with an air-fuel equivalence ratio (AFR) of 0.5. 52 Air and fuel are injected through the main inlet, and oxygen is injected through the oxidizer inlet ( Figure 1 c). The mass flow rate of air and fuel from the main inlet and the mass flow rate of oxygen from the oxidizer inlet are presented in Table 6 .…”

Section: Numerical Modelmentioning

confidence: 99%

“…In situ laser diagnostics was conducted in the reactor core through optical access ports located 1.7 and 2.15 m downstream of the fuel inlet. Gas temperature and H 2 O concentration were measured at both ports using TDLAS systems operating at 1.4 m, , and K species concentrations were measured at the upper port using a PF-TDLAS system. − The PF-TDLAS system (Figure a) consisted of a tunable diode laser emitting around 770 nm (probe laser) and ns-pulsed Nd:YAG lasers at 266 and 355 nm (pump lasers). The probe laser wavelength was scanned across the atomic K absorption line at 769.9 nm, and the atomic K concentration was obtained by fitting a Voigt profile to the measured absorbance.…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…The boundary conditions in the simulations are set according to the experimental conditions during the gasification of FR with an air-fuel equivalence ratio (AFR) of 0.5 . Air and fuel are injected through the main inlet, and oxygen is injected through the oxidizer inlet (Figure c).…”

Section: Numerical Modelmentioning

confidence: 99%

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Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier

et al. 2023

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In this study, a Eulerian−Lagrangian model is used to study biomass gasification and release of potassium species in a 140 kW atmospheric entrained flow gasifier (EFG). Experimental measurements of water concentration and temperature inside the reactor, together with the gas composition at the gasifier outlet, are used to validate the model. For the first time, a detailed K-release model is used to predict the concentrations of gas-phase K species inside the gasifier, and the results are compared with experimental measurements from an optical port in the EFG. The prediction errors for atomic potassium (K), potassium chloride (KCl), potassium hydroxide (KOH), and total potassium are 1.4%, 9.8%, 5.5%, and 5.7%, respectively, which are within the uncertainty limits of the measurements. The numerical model is used to identify and study the main phenomena that occur in different zones of the gasifier. Five zones are identified in which drying, pyrolysis, combustion, recirculation, and gasification are active. The model was then used to study the transformation and release of different K species from biomass particles. It was found that, for the forest residue fuel that was used in the present study, the organic part of K is released at the shortest residence time, followed by the release of inorganic K at higher residence times. The release of inorganic salts starts by evaporation of KCl and continues by dissociation of K 2 CO 3 and K 2 SO 4 , which forms gas-phase KOH. The major fraction of K is released around the combustion zone (around 0.7−1.3 m downstream of the inlet) due to the high H 2 O concentration and temperature. These conditions lead to rapid dissociation of K 2 CO 3 and K 2 SO 4 , which increases the total K concentration from 336 to 510 ppm in the combustion zone. The dissociation of the inorganic salts and KOH formation continues in the gasification zone at a lower rate; hence, the total K concentration slowly increases from 510 ppm at 1.3 m to 561 ppm at the outlet.

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Section: Experimental Measurementsmentioning

confidence: 99%

Section: Numerical Modelmentioning

confidence: 99%

Section: Experimental Measurementsmentioning

confidence: 99%

Section: Numerical Modelmentioning

confidence: 99%

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Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier

et al. 2023

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“…It has been used to monitor the intermediate conversion processes of specific gas components in complex reaction flow fields. In the application of TDLAS, Sepman et al utilized it to in situ measure CH 4 , H 2 O, soot, and gas temperature in the reactor core of a biomass gasifier, and found that CH 4 mainly originates from the pyrolysis of fuel particles in the lower temperature region of the reactor core, based on the spatiotemporal characteristics of CH 4 . Furthermore, they measured the concentrations of H 2 O, CO, and CO 2 during the combustion processes of diesel and biomass by TDLAS, and analyzed the composition of the exhaust gases by FTIR, observing that diesel combustion was completed at the TDLAS measurement location, while wood combustion was still in progress.…”

Section: Introductionmentioning

confidence: 99%

Conversion Mechanism of Organic Components during the Eucalyptus Biomass Pyrolysis Process Based on the Multispectral Association Method

Lin,

Dong,

Nie

et al. 2024

Energy Fuels

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It is important to understand the transformation mechanism of the pyrolysis process, which is a crucial method for thermally utilizing solid fuels. In this work, multispectral association technology was employed to measure the pyrolysis process of biomass (eucalyptus) and investigate the spatiotemporal characteristics of its gas−solid products. We utilized tunable diode laser absorption spectroscopy (TDLAS) to quantitatively measure the gases produced during the pyrolysis process (CH 4 , H 2 O), which reflects the progress of the pyrolysis. Laser-induced breakdown spectroscopy (LIBS) was used to qualitatively measure characteristic elements such as C, C 2 , and H in the gas phase, revealing the product conversion trends. In addition, Raman spectroscopy was used to provide information about the molecular structure and functional group changes in biomass pyrolysis char. The evolving pattern of the Raman spectrum revealed that biomass char exhibits high reactivity during the dehydration and devolatilization stage, with a swift detachment of the methyl functional group. TDLAS and LIBS measurements revealed that a substantial amount of methane was produced, accompanied by the initial release peaks of the C and C 2 spectrum. During the secondary cracking stage, the reactivity and the rate of functional group detachment of biomass char gradually diminished. Methane production is relatively low in this stage, and the second-release peaks in the C and C 2 spectra might be associated with other organic gases generated through tar cracking. In addition, through multispectral association measurements on the samples with varying moisture content, it was found that moisture would increase the reactivity and the rate of functional group detachment of the biomass char, resulting in an increase in methane yield. Moreover, the spatial distribution characteristics of TDLAS and LIBS above the samples revealed that moisture facilitates the cracking of tar, resulting in the production of small molecular gases.

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Simultaneous measurements of temperature, CO2 concentration and soot volume fraction in counterflow diffusion flames using a single mid-infrared laser

Sheng

Wen

et al. 2022

Appl. Phys. B

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Laser-based detection of methane and soot during entrained-flow biomass gasification

Cited by 16 publications

References 47 publications

Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier

Numerical Study and Experimental Verification of Biomass Conversion and Potassium Release in a 140 kW Entrained Flow Gasifier

Conversion Mechanism of Organic Components during the Eucalyptus Biomass Pyrolysis Process Based on the Multispectral Association Method

Simultaneous measurements of temperature, CO2 concentration and soot volume fraction in counterflow diffusion flames using a single mid-infrared laser

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