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Tunable diode laser absorptionspectroscopy of atomic potassium in a KOH-seeded flat flame
Umeå University, Faculty of Science and Technology, Department of Physics. (Applied laser spectroscopy group)
2018 (English)Independent thesis Advanced level (degree of Master (Two Years)), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

Potassium (K) is the main ash-forming element released from biomass during thermochemical conversion. A better understanding of K chemistry and monitoring of K species is needed to optimize combustion systems. Since K species are highly reactive and prevailing concentrations depend on the conversion conditions, accurate quantification requires in situ measurement techniques. Tunable diode laser absorption spectroscopy with a single-mode distributed feedback laser is used to probe the D1 transition of atomic potassium, K(g), at 769.9 nm. The large current tuning range of the diode laser (5 cm-1) enables monitoringthe wings of the absorption profile. Fitting to the acquired line shape wings is used as astrategy to enhance the dynamic range of the sensor and measure K(g) concentrations even under optically thick condition. A potassium-rich combustion environment is simulated by converting KOH salt in a premixed methane/air flat flame. Quantitative measurements of K(g) are made at 75 positions in the flame. This yields radial K(g) profiles at three different heightsin the plume above the KOH salt and an axial profile at the burner center. The acquired average K(g) concentrations are corrected for effective plume size, i.e. the absorption pathlength determined from the radial profiles. Knowledge of the K(g) distribution in flames can lead to a better understanding of K release and primary reaction kinetics.

Place, publisher, year, edition, pages
2018. , p. 30
National Category
Atom and Molecular Physics and Optics
Identifiers
URN: urn:nbn:se:umu:diva-146503OAI: oai:DiVA.org:umu-146503DiVA, id: diva2:1196881
Subject / course
Fysik D - examensarbete II
Educational program
Master's Programme in Physics
Presentation
2018-03-22, Bottenhavet, Fysik huset, Umeå universititet, Umeå, 14:00 (English)
Supervisors
Examiners
Available from: 2018-04-11 Created: 2018-04-11 Last updated: 2018-04-11Bibliographically approved

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Master thesis(5631 kB)33 downloads
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Type fulltextMimetype application/pdf

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Atom and Molecular Physics and Optics

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CiteExportLink to record
Permanent link

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Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
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  • Other locale
More languages
Output format
  • html
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  • asciidoc
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