Iannello, Stefano;
Macrì, Domenico;
Materazzi, Massimiliano;
(2023)
A comprehensive assessment of endogenous bubbles properties in fluidized bed reactors via X-ray imaging.
Powder Technology
, Article 118013. 10.1016/j.powtec.2022.118013.
(In press).
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Abstract
Properties of endogenous bubbles released during the devolatilization of a single biomass particle under inert conditions have been investigated by means of advanced X-ray imaging techniques. Distribution of void fraction showed that endogenous bubbles structure resembles that of classic bubbles observed in fluidized bed reactors, constituted by a cloud, wake and a central void region. A value of about 0.25 for the wake fraction has been obtained from experiments, which is in agreement with literature data for Geldart B particles. Volume of cloud region as a function of relative bubble velocity was generally well-described by the theoretical models of Davidson and Murray, showing effective recirculation of volatile matter around the bubble. Moreover, lack of mixing between bubbles and emulsion phase, as predicted by the Davidson's theory for classic bubbles, confirmed the bypass phenomenon observed for endogenous bubbles in previous studies. Owing to the non-invasive nature of the X-ray technique employed, it was possible to estimate the main features of endogenous bubbles with high accuracy. Knowledge provided in this work can be easily implemented to improve modelling of fluidized bed reactors applied to advanced thermochemical conversions, such as gasification and pyrolysis, of biomass and waste materials.
| Type: | Article |
|---|---|
| Title: | A comprehensive assessment of endogenous bubbles properties in fluidized bed reactors via X-ray imaging |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.powtec.2022.118013 |
| Publisher version: | https://doi.org/10.1016/j.powtec.2022.118013 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Devolatilization, Fluidized bed, Biomass conversion, Endogenous bubbles, X-ray imaging |
| UCL classification: | UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering UCL > Provost and Vice Provost Offices > UCL BEAMS UCL |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10157795 |
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