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Shedding light on the governing mechanisms for insufficient CO and H2 burnout in the presence of potassium, chlorine and sulfur

Berdugo Vilches, Teresa ; Weng, Wubin LU ; Glarborg, Peter ; Li, Zhongshan LU ; Thunman, Henrik and Seemann, Martin (2020) In Fuel 273.
Abstract

Based on the experiences of insufficient burnout in industrial fluidized bed furnaces despite adequate mixing and availability of oxidizer, the influence of potassium on CO and H2 oxidation in combustion environments was investigated. The combustion environments were provided by a laminar flame burner in a range relevant to industrial furnaces, i.e. 845 °C to 1275 °C and excess air ratios ranging from 1.05 to 1.65. Potassium, in the form of KOH, was homogeneously introduced into the hot gas environments to investigate its effect on the radical pool. To quantitatively determine key species that are involved in the oxidation mechanism (CO, H2, KOH, OH radicals, K atoms), a combination of measurement systems was... (More)

Based on the experiences of insufficient burnout in industrial fluidized bed furnaces despite adequate mixing and availability of oxidizer, the influence of potassium on CO and H2 oxidation in combustion environments was investigated. The combustion environments were provided by a laminar flame burner in a range relevant to industrial furnaces, i.e. 845 °C to 1275 °C and excess air ratios ranging from 1.05 to 1.65. Potassium, in the form of KOH, was homogeneously introduced into the hot gas environments to investigate its effect on the radical pool. To quantitatively determine key species that are involved in the oxidation mechanism (CO, H2, KOH, OH radicals, K atoms), a combination of measurement systems was applied: micro-gas chromatography, broadband UV absorption spectroscopy and tunable diode laser absorption spectroscopy. The inhibition effect of potassium on CO and H2 oxidation in excess air was experimentally confirmed and attributed to the chain-terminating reaction between KOH, K atoms and OH radicals, which enhanced the OH radical consumption. The addition of chlorine or sulfur could reduce the concentrations of KOH and K atoms and consequently eliminated the inhibition on CO and H2 oxidation. Existing kinetic mechanisms underestimate the inhibiting effect of potassium and they fail to predict the effect of temperature on CO and H2 concentration when potassium and sulfur co-exist. This work advances the need to revise existing kinetic mechanisms to fully capture the interplay of K and S in the oxidation of CO and H2 in industrial fluidized bed furnaces.

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; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
CO oxidation, Combustion, Inhibition, Potassium, TDLAS, UV absorption spectroscopy
in
Fuel
volume
273
article number
117762
publisher
Elsevier
external identifiers
  • scopus:85082880750
ISSN
0016-2361
DOI
10.1016/j.fuel.2020.117762
language
English
LU publication?
yes
id
a468c785-19f6-4fe4-bd93-373d9ba660f8
date added to LUP
2020-04-15 16:18:25
date last changed
2020-04-22 05:54:51
@article{a468c785-19f6-4fe4-bd93-373d9ba660f8,
  abstract     = {<p>Based on the experiences of insufficient burnout in industrial fluidized bed furnaces despite adequate mixing and availability of oxidizer, the influence of potassium on CO and H<sub>2</sub> oxidation in combustion environments was investigated. The combustion environments were provided by a laminar flame burner in a range relevant to industrial furnaces, i.e. 845 °C to 1275 °C and excess air ratios ranging from 1.05 to 1.65. Potassium, in the form of KOH, was homogeneously introduced into the hot gas environments to investigate its effect on the radical pool. To quantitatively determine key species that are involved in the oxidation mechanism (CO, H<sub>2</sub>, KOH, OH radicals, K atoms), a combination of measurement systems was applied: micro-gas chromatography, broadband UV absorption spectroscopy and tunable diode laser absorption spectroscopy. The inhibition effect of potassium on CO and H<sub>2</sub> oxidation in excess air was experimentally confirmed and attributed to the chain-terminating reaction between KOH, K atoms and OH radicals, which enhanced the OH radical consumption. The addition of chlorine or sulfur could reduce the concentrations of KOH and K atoms and consequently eliminated the inhibition on CO and H<sub>2</sub> oxidation. Existing kinetic mechanisms underestimate the inhibiting effect of potassium and they fail to predict the effect of temperature on CO and H<sub>2</sub> concentration when potassium and sulfur co-exist. This work advances the need to revise existing kinetic mechanisms to fully capture the interplay of K and S in the oxidation of CO and H<sub>2</sub> in industrial fluidized bed furnaces.</p>},
  author       = {Berdugo Vilches, Teresa and Weng, Wubin and Glarborg, Peter and Li, Zhongshan and Thunman, Henrik and Seemann, Martin},
  issn         = {0016-2361},
  language     = {eng},
  publisher    = {Elsevier},
  series       = {Fuel},
  title        = {Shedding light on the governing mechanisms for insufficient CO and H<sub>2</sub> burnout in the presence of potassium, chlorine and sulfur},
  url          = {http://dx.doi.org/10.1016/j.fuel.2020.117762},
  doi          = {10.1016/j.fuel.2020.117762},
  volume       = {273},
  year         = {2020},
}