Quantitative imaging of potassium release from single burning pulverized biomass char particles

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The release of potassium from single burning pulverized wheat straw char particles was quantitatively measured using laser-induced photofragmentation fluorescence (LIPF). The char particles were prepared in a drop tube furnace at 1000 °C from wheat straw particles with sizes in the range 224–250 µm. Subsequently, the char particles were injected upward into a hot flue gas flow produced by a premixed CH4/air flame anchored on a McKenna burner. The flue gas had a mean temperature of 1580 K and a mean O2 concentration of 6.5 vol%. The 193 nm laser beam from an ArF Excimer laser was formed into a collimated laser sheet to photodissociate potassium hydroxide (KOH) and potassium chloride (KCl) around the burning char particles, and the signal of the produced fluorescence was captured by a camera. The measurements were conducted for char particles during residence times in the flue gas between 10 and 70 ms. Quantitative data was obtained from a direct calibration of the LIPF signal in hot gas products doped with known amounts of KOH and KCl. The maximum potassium concentration measured surrounding the burning char particles was over 40 ppm. During the oxidation period until 70 ms, the measured potassium release rate remained almost constant at around 0.5 µg/s, with more than 60% of the potassium being released in the form of KOH. The results indicate that the LIPF imaging method can be used to study the potassium release from burning biomass fuels.


Enheter & grupper
Externa organisationer
  • Lisboa
  • University of Lisbon

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Energisystem


StatusPublished - 2020
Peer review utfördJa