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Gas phase combustion in the vicinity of a biomass particle during devolatilization – Model development and experimental verification

Fatehi, Hesameddin LU ; Schmidt, Florian M. and Bai, Xue Song LU (2018) In Combustion and Flame 196. p.351-363
Abstract

A numerical and experimental study on the devolatilization of a large biomass particle is carried out to quantify the effect of homogeneous volatile combustion on the conversion of the particle and on the temperature and species distribution at the particle vicinity. A global chemical kinetic mechanism and a detailed reaction mechanism are considered in a one dimensional numerical model that takes into account preferential diffusivity and a detailed composition of tar species. An adaptive moving mesh is employed to capture the changes in the domain due to particle shrinkage. The effect of gas phase reactions on pyrolysis time, temperature and species distribution close to the particle is studied and compared to experiments. Online in... (More)

A numerical and experimental study on the devolatilization of a large biomass particle is carried out to quantify the effect of homogeneous volatile combustion on the conversion of the particle and on the temperature and species distribution at the particle vicinity. A global chemical kinetic mechanism and a detailed reaction mechanism are considered in a one dimensional numerical model that takes into account preferential diffusivity and a detailed composition of tar species. An adaptive moving mesh is employed to capture the changes in the domain due to particle shrinkage. The effect of gas phase reactions on pyrolysis time, temperature and species distribution close to the particle is studied and compared to experiments. Online in situ measurements of average H2O mole fraction and gas temperature above a softwood pellet are conducted in a reactor using tunable diode laser absorption spectroscopy (TDLAS) while recording the particle mass loss. The results show that the volatile combustion plays an important role in the prediction of biomass conversion during the devolatilization stage. It is shown that the global reaction mechanism predicts a thin flame front in the vicinity of the particle deviating from the measured temperature and H2O distribution over different heights above the particle. A better agreement between numerical and experimental results is obtained using the detailed reaction mechanism, which predicts a wider reaction zone.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biomass particle, Boundary layer, Combustion, Numerical modeling, Tunable diode laser absorption spectroscopy (TDLAS)
in
Combustion and Flame
volume
196
pages
13 pages
publisher
Elsevier
external identifiers
  • scopus:85049728200
ISSN
0010-2180
DOI
10.1016/j.combustflame.2018.06.025
language
English
LU publication?
yes
id
e6584dd4-594a-47fb-83c9-eaa3014699d8
date added to LUP
2018-07-24 09:22:47
date last changed
2019-10-15 06:42:10
@article{e6584dd4-594a-47fb-83c9-eaa3014699d8,
  abstract     = {<p>A numerical and experimental study on the devolatilization of a large biomass particle is carried out to quantify the effect of homogeneous volatile combustion on the conversion of the particle and on the temperature and species distribution at the particle vicinity. A global chemical kinetic mechanism and a detailed reaction mechanism are considered in a one dimensional numerical model that takes into account preferential diffusivity and a detailed composition of tar species. An adaptive moving mesh is employed to capture the changes in the domain due to particle shrinkage. The effect of gas phase reactions on pyrolysis time, temperature and species distribution close to the particle is studied and compared to experiments. Online in situ measurements of average H<sub>2</sub>O mole fraction and gas temperature above a softwood pellet are conducted in a reactor using tunable diode laser absorption spectroscopy (TDLAS) while recording the particle mass loss. The results show that the volatile combustion plays an important role in the prediction of biomass conversion during the devolatilization stage. It is shown that the global reaction mechanism predicts a thin flame front in the vicinity of the particle deviating from the measured temperature and H<sub>2</sub>O distribution over different heights above the particle. A better agreement between numerical and experimental results is obtained using the detailed reaction mechanism, which predicts a wider reaction zone.</p>},
  author       = {Fatehi, Hesameddin and Schmidt, Florian M. and Bai, Xue Song},
  issn         = {0010-2180},
  keyword      = {Biomass particle,Boundary layer,Combustion,Numerical modeling,Tunable diode laser absorption spectroscopy (TDLAS)},
  language     = {eng},
  month        = {10},
  pages        = {351--363},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Gas phase combustion in the vicinity of a biomass particle during devolatilization – Model development and experimental verification},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2018.06.025},
  volume       = {196},
  year         = {2018},
}