Photofragmentation and atomic absorption spectroscopy for NaOH and NaCl detection in combustion environments
(2027) In Fuel 428.- Abstract
NaOH and NaCl vapor are key alkali compounds released during the thermal conversion of high-alkali coal and municipal solid waste, and their accurate measurement is crucial for understanding the mechanisms of ash deposition, slagging, and other related issues. However, in-situ and species-specific measurement techniques with high sensitivity for NaOH and NaCl molecules in hash combustion environments remain largely underdeveloped. Based on photodissociation and laser atomic absorption spectroscopy, this study develops a quantitative diagnostic method for NaOH and NaCl applicable to high temperature combustion environments. During photodissociation process, the distinct photofragmentation properties of NaCl and NaOH provide... (More)
NaOH and NaCl vapor are key alkali compounds released during the thermal conversion of high-alkali coal and municipal solid waste, and their accurate measurement is crucial for understanding the mechanisms of ash deposition, slagging, and other related issues. However, in-situ and species-specific measurement techniques with high sensitivity for NaOH and NaCl molecules in hash combustion environments remain largely underdeveloped. Based on photodissociation and laser atomic absorption spectroscopy, this study develops a quantitative diagnostic method for NaOH and NaCl applicable to high temperature combustion environments. During photodissociation process, the distinct photofragmentation properties of NaCl and NaOH provide straightforward component discrimination: 355 nm laser can photodissociate NaOH in generating Na atoms, while 266 nm laser photodissociate dominantly NaCl, which enables their differentiation. In subsequent measurements of photofragmentation-induced atomic concentrations, the absorption cross-section of photogenerated Na atoms at the 589.6 nm line was experimentally determined to ensure the measurement accuracy. The performance of two optical configurations (coaxial and orthogonal) was systematically compared, where the coaxial one is suitable for industrial applications, while the orthogonal one offers spatial resolution. Based on the photofragmentation and atomic absorption spectroscopy, a detection limit of 271 ppb and 303 ppb for NaOH and NaCl with a temporal resolution of 0.1 s was achieved using orthogonal configuration. Further applications in homogeneous reaction and heterogeneous coal pellet combustion demonstrate the technique’s capability for accurate spatially resolved measurement. Besides, adaptability of this method to the combustion environments in a 100-kW pilot-scale down-fired furnace was estimated, providing an effective tool for online monitoring of NaOH and NaCl release and transformation during combustion processes.
(Less)
- author
- Dai, Yan ; Weng, Wubin LU ; Jiang, Junjie ; Chen, Qingchi ; Liu, Siyu LU ; Wang, Shixing ; He, Yong ; Li, Zhongshan LU and Wang, Zhihua
- organization
- publishing date
- 2027-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Alkali detection, Atomic absorption spectroscopy, Combustion, Laser diagnostics, Photofragmentation
- in
- Fuel
- volume
- 428
- article number
- 140175
- publisher
- Elsevier
- external identifiers
-
- scopus:105040963087
- ISSN
- 0016-2361
- DOI
- 10.1016/j.fuel.2026.140175
- language
- English
- LU publication?
- yes
- id
- a627884d-3c0e-4e23-91ea-cdc39931e7dc
- date added to LUP
- 2026-07-01 12:25:20
- date last changed
- 2026-07-01 12:25:20
@article{a627884d-3c0e-4e23-91ea-cdc39931e7dc,
abstract = {{<p>NaOH and NaCl vapor are key alkali compounds released during the thermal conversion of high-alkali coal and municipal solid waste, and their accurate measurement is crucial for understanding the mechanisms of ash deposition, slagging, and other related issues. However, in-situ and species-specific measurement techniques with high sensitivity for NaOH and NaCl molecules in hash combustion environments remain largely underdeveloped. Based on photodissociation and laser atomic absorption spectroscopy, this study develops a quantitative diagnostic method for NaOH and NaCl applicable to high temperature combustion environments. During photodissociation process, the distinct photofragmentation properties of NaCl and NaOH provide straightforward component discrimination: 355 nm laser can photodissociate NaOH in generating Na atoms, while 266 nm laser photodissociate dominantly NaCl, which enables their differentiation. In subsequent measurements of photofragmentation-induced atomic concentrations, the absorption cross-section of photogenerated Na atoms at the 589.6 nm line was experimentally determined to ensure the measurement accuracy. The performance of two optical configurations (coaxial and orthogonal) was systematically compared, where the coaxial one is suitable for industrial applications, while the orthogonal one offers spatial resolution. Based on the photofragmentation and atomic absorption spectroscopy, a detection limit of 271 ppb and 303 ppb for NaOH and NaCl with a temporal resolution of 0.1 s was achieved using orthogonal configuration. Further applications in homogeneous reaction and heterogeneous coal pellet combustion demonstrate the technique’s capability for accurate spatially resolved measurement. Besides, adaptability of this method to the combustion environments in a 100-kW pilot-scale down-fired furnace was estimated, providing an effective tool for online monitoring of NaOH and NaCl release and transformation during combustion processes.</p>}},
author = {{Dai, Yan and Weng, Wubin and Jiang, Junjie and Chen, Qingchi and Liu, Siyu and Wang, Shixing and He, Yong and Li, Zhongshan and Wang, Zhihua}},
issn = {{0016-2361}},
keywords = {{Alkali detection; Atomic absorption spectroscopy; Combustion; Laser diagnostics; Photofragmentation}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Fuel}},
title = {{Photofragmentation and atomic absorption spectroscopy for NaOH and NaCl detection in combustion environments}},
url = {{http://dx.doi.org/10.1016/j.fuel.2026.140175}},
doi = {{10.1016/j.fuel.2026.140175}},
volume = {{428}},
year = {{2027}},
}