Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Quantitative K-Cl-S chemistry in thermochemical conversion processes using in situ optical diagnostics

Weng, Wubin LU ; Li, Zhongshan LU ; Wu, Hao ; Aldén, Marcus LU and Glarborg, Peter (2021) In Proceedings of the Combustion Institute 38(4). p.5219-5227
Abstract

The sulfation of gas-phase KOH and KCl was investigated in both oxidizing and reducing atmospheres at temperatures of 1120 K, 1260 K, 1390 K, and 1550 K. Well-defined gas environments were generated in a laminar flame burner fuelled with CH4/air/O2/N2. Atomized K2CO3 and KCl water solution fog and SO2 were introduced into the hot gas as sources of potassium, chlorine, and sulfur, respectively. The in situ concentrations of KOH, KCl, and OH radicals were measured using broadband UV absorption spectroscopy, and the concentration of K atom was measured using TDLAS at 769.9 nm and 404.4 nm. The nucleated and condensed K2SO4 aerosols were visualized as... (More)

The sulfation of gas-phase KOH and KCl was investigated in both oxidizing and reducing atmospheres at temperatures of 1120 K, 1260 K, 1390 K, and 1550 K. Well-defined gas environments were generated in a laminar flame burner fuelled with CH4/air/O2/N2. Atomized K2CO3 and KCl water solution fog and SO2 were introduced into the hot gas as sources of potassium, chlorine, and sulfur, respectively. The in situ concentrations of KOH, KCl, and OH radicals were measured using broadband UV absorption spectroscopy, and the concentration of K atom was measured using TDLAS at 769.9 nm and 404.4 nm. The nucleated and condensed K2SO4 aerosols were visualized as illuminated by a green laser sheet. With SO2 addition, reduced concentrations of KOH, KCl, and K atom were measured in the hot gas. The sulfation was more significant for the low temperature cases. KOH was sulfated more rapidly than KCl. K2SO4 aerosols, formed by homogeneous nucleation, were observed at temperatures below 1260 K. At 1390 K, no aerosols were formed, indicating that the consumed KOH was transformed into gaseous KHSO4 or K2SO4. K atoms formed in the hot flue gas with KOH addition enhanced the consumption of OH radicals except at the high-temperature case at 1550 K. At 1120 K and 1260 K, the sulfation of KOH with SO2 seeding reduced the concentration of K atom, resulting in less OH radical consumption. Studies were also conducted in a hot reducing environment at 1140 K, with the flame at an equivalence ratio of 1.31. Similar to the observation in the oxidizing atmosphere, the concentrations of KOH and K atom decreased dramatically with SO2 seeding. An unknown absorption spectrum observed was attributed to UV absorption by KOSO. The experimental results were used to evaluate a detailed K-Cl-S reaction mechanism, and a reasonable agreement was obtained.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biomass combustion, Chemical kinetic model, Potassium sulfation, Quantitative measurement, UV absorption spectroscopy
in
Proceedings of the Combustion Institute
volume
38
issue
4
pages
9 pages
publisher
Elsevier
external identifiers
  • scopus:85091523844
ISSN
1540-7489
DOI
10.1016/j.proci.2020.05.058
language
English
LU publication?
yes
id
a81425b0-6935-4182-b149-a7ce39af54df
date added to LUP
2020-10-28 15:13:13
date last changed
2022-04-19 01:26:49
@article{a81425b0-6935-4182-b149-a7ce39af54df,
  abstract     = {{<p>The sulfation of gas-phase KOH and KCl was investigated in both oxidizing and reducing atmospheres at temperatures of 1120 K, 1260 K, 1390 K, and 1550 K. Well-defined gas environments were generated in a laminar flame burner fuelled with CH<sub>4</sub>/air/O<sub>2</sub>/N<sub>2</sub>. Atomized K<sub>2</sub>CO<sub>3</sub> and KCl water solution fog and SO<sub>2</sub> were introduced into the hot gas as sources of potassium, chlorine, and sulfur, respectively. The in situ concentrations of KOH, KCl, and OH radicals were measured using broadband UV absorption spectroscopy, and the concentration of K atom was measured using TDLAS at 769.9 nm and 404.4 nm. The nucleated and condensed K<sub>2</sub>SO<sub>4</sub> aerosols were visualized as illuminated by a green laser sheet. With SO<sub>2</sub> addition, reduced concentrations of KOH, KCl, and K atom were measured in the hot gas. The sulfation was more significant for the low temperature cases. KOH was sulfated more rapidly than KCl. K<sub>2</sub>SO<sub>4</sub> aerosols, formed by homogeneous nucleation, were observed at temperatures below 1260 K. At 1390 K, no aerosols were formed, indicating that the consumed KOH was transformed into gaseous KHSO<sub>4</sub> or K<sub>2</sub>SO<sub>4</sub>. K atoms formed in the hot flue gas with KOH addition enhanced the consumption of OH radicals except at the high-temperature case at 1550 K. At 1120 K and 1260 K, the sulfation of KOH with SO<sub>2</sub> seeding reduced the concentration of K atom, resulting in less OH radical consumption. Studies were also conducted in a hot reducing environment at 1140 K, with the flame at an equivalence ratio of 1.31. Similar to the observation in the oxidizing atmosphere, the concentrations of KOH and K atom decreased dramatically with SO<sub>2</sub> seeding. An unknown absorption spectrum observed was attributed to UV absorption by KOSO. The experimental results were used to evaluate a detailed K-Cl-S reaction mechanism, and a reasonable agreement was obtained.</p>}},
  author       = {{Weng, Wubin and Li, Zhongshan and Wu, Hao and Aldén, Marcus and Glarborg, Peter}},
  issn         = {{1540-7489}},
  keywords     = {{Biomass combustion; Chemical kinetic model; Potassium sulfation; Quantitative measurement; UV absorption spectroscopy}},
  language     = {{eng}},
  number       = {{4}},
  pages        = {{5219--5227}},
  publisher    = {{Elsevier}},
  series       = {{Proceedings of the Combustion Institute}},
  title        = {{Quantitative K-Cl-S chemistry in thermochemical conversion processes using in situ optical diagnostics}},
  url          = {{http://dx.doi.org/10.1016/j.proci.2020.05.058}},
  doi          = {{10.1016/j.proci.2020.05.058}},
  volume       = {{38}},
  year         = {{2021}},
}