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Computational study of the combustion process and NO formation in a small-scale wood pellet furnace

Klason, Torbern LU and Bai, Xue-Song LU (2007) In Fuel 86(10-11). p.1465-1474
Abstract
This paper presents a computational study of the combustion process of wood pellets in a small-scale grate fired furnace. The objectives were to obtain detailed information on the combustion characteristics and NO formation in the furnace, and to examine the effect of secondary air on the combustion process. The simulation results were compared with experimental data in terms of flame temperature and distributions of species concentrations, including CO and NO. It was shown that the combustion process is strongly controlled by the inflow turbulence from the secondary and tertiary air jets. The combustion process is not sensitive to the bed combustion process in the present test case. The high speed air flow from the secondary and tertiary... (More)
This paper presents a computational study of the combustion process of wood pellets in a small-scale grate fired furnace. The objectives were to obtain detailed information on the combustion characteristics and NO formation in the furnace, and to examine the effect of secondary air on the combustion process. The simulation results were compared with experimental data in terms of flame temperature and distributions of species concentrations, including CO and NO. It was shown that the combustion process is strongly controlled by the inflow turbulence from the secondary and tertiary air jets. The combustion process is not sensitive to the bed combustion process in the present test case. The high speed air flow from the secondary and tertiary air inlets 'destroys' the history of the effluent volatile gases from the fuel bed. Different paths for the NO emission were investigated, including the thermal NO, the fuel-NO and NO from the N2O intermediate mechanisms. The fuel-NO path is responsible for the rapid NO increase and the high NO peak near the fuel bed. Fuel-NO is rather low far downstream owing to the rather low nitrogen content in the fuel (less than 0.1% on mass basis), and the de-NOx reactions with NH3. NO is likely formed from the N2O intermediate mechanism far downstream. (c) 2006 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
combustion of wood pellets, volatile oxidation, mechanisms of NO, formation
in
Fuel
volume
86
issue
10-11
pages
1465 - 1474
publisher
Elsevier
external identifiers
  • wos:000247978600016
  • scopus:34147147930
ISSN
1873-7153
DOI
10.1016/j.fuel.2006.11.022
language
English
LU publication?
yes
id
ce09b4e2-37e9-418f-909d-6f0e9bbd5d98 (old id 646493)
date added to LUP
2007-12-13 16:55:44
date last changed
2017-10-01 04:51:01
@article{ce09b4e2-37e9-418f-909d-6f0e9bbd5d98,
  abstract     = {This paper presents a computational study of the combustion process of wood pellets in a small-scale grate fired furnace. The objectives were to obtain detailed information on the combustion characteristics and NO formation in the furnace, and to examine the effect of secondary air on the combustion process. The simulation results were compared with experimental data in terms of flame temperature and distributions of species concentrations, including CO and NO. It was shown that the combustion process is strongly controlled by the inflow turbulence from the secondary and tertiary air jets. The combustion process is not sensitive to the bed combustion process in the present test case. The high speed air flow from the secondary and tertiary air inlets 'destroys' the history of the effluent volatile gases from the fuel bed. Different paths for the NO emission were investigated, including the thermal NO, the fuel-NO and NO from the N2O intermediate mechanisms. The fuel-NO path is responsible for the rapid NO increase and the high NO peak near the fuel bed. Fuel-NO is rather low far downstream owing to the rather low nitrogen content in the fuel (less than 0.1% on mass basis), and the de-NOx reactions with NH3. NO is likely formed from the N2O intermediate mechanism far downstream. (c) 2006 Elsevier Ltd. All rights reserved.},
  author       = {Klason, Torbern and Bai, Xue-Song},
  issn         = {1873-7153},
  keyword      = {combustion of wood pellets,volatile oxidation,mechanisms of NO,formation},
  language     = {eng},
  number       = {10-11},
  pages        = {1465--1474},
  publisher    = {Elsevier},
  series       = {Fuel},
  title        = {Computational study of the combustion process and NO formation in a small-scale wood pellet furnace},
  url          = {http://dx.doi.org/10.1016/j.fuel.2006.11.022},
  volume       = {86},
  year         = {2007},
}