Modeling and experiments of biomass combustion in a large-scale grate boiler

Chungen Yin, Lasse Rosendahl, Søren Knudsen Kær, Henrik Sørensen, Sønnik Clausen, Torben Hille, Søren L. Hvid

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

Abstract

Grate furnaces are currently a main workhorse in large-scale firing of biomass for heat and power production. A biomass grate fired furnace can be interpreted as a cross-flow reactor, where biomass is fed in a thick layer perpendicular to the primary air flow. The bottom of the biomass bed is exposed to preheated inlet air while the top of the bed resides within the furnace. Mathematical modeling is an efficient way to understand and improve the operation and design of combustion systems. Compared to modeling of pulverized fuel furnaces, CFD modeling of biomass-fired grate furnaces is inherently more difficult due to the complexity of the solid biomass fuel bed on the grate, the turbulent reacting flow in the combustion chamber and the intensive interaction between them. This paper presents the CFD validation efforts for a modern large-scale biomass-fired grate boiler. Modeling and experiments are both done for the grate boiler. The comparison between them shows an overall acceptable agreement in tendency. However at some measuring ports, big discrepancies between the modeling and the experiments are observed, mainly because the modeling-based boundary conditions (BCs) could differ quite much with the conditions in the real furnace. Combustion instabilities in the fuel bed impose big challenges to give reliable grate inlet BCs for the CFD modeling; the deposits formed on furnace walls and air nozzles make it difficult to define precisely the wall BCs and air jet BCs that a reliable CFD needs. The CFD results show reasonably the mixing and combustion performance in the furnace based on the design drawings; while the measurement results reflect reliably the combustion performance in the real furnace in operation.
Original languageEnglish
Title of host publicationProceedings of International Conference on Power Engineering
Number of pages7
PublisherSpringer
Publication date2007
Pages1173-1179
ISBN (Print)978-3-540-76693-3
ISBN (Electronic)978-3-540-76694-0
Publication statusPublished - 2007
EventInternational Conference on Power Engineering 2007 - Hangzhou, China
Duration: 23 Oct 200727 Oct 2007

Conference

ConferenceInternational Conference on Power Engineering 2007
CountryChina
CityHangzhou
Period23/10/200727/10/2007

Fingerprint

Boilers
Biomass
Furnaces
Computational fluid dynamics
Experiments
Boundary conditions
Air
Pulverized fuel
Air intakes
Combustion chambers
Turbulent flow
Nozzles
Deposits

Keywords

  • Biomass combustion
  • Grate boiler
  • Combustion instabilities
  • CFD
  • Water-cooled vibrating grate
  • CO2 emission

Cite this

Yin, C., Rosendahl, L., Kær, S. K., Sørensen, H., Clausen, S., Hille, T., & Hvid, S. L. (2007). Modeling and experiments of biomass combustion in a large-scale grate boiler. In Proceedings of International Conference on Power Engineering (pp. 1173-1179). Springer.
Yin, Chungen ; Rosendahl, Lasse ; Kær, Søren Knudsen ; Sørensen, Henrik ; Clausen, Sønnik ; Hille, Torben ; Hvid, Søren L. / Modeling and experiments of biomass combustion in a large-scale grate boiler. Proceedings of International Conference on Power Engineering. Springer, 2007. pp. 1173-1179
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title = "Modeling and experiments of biomass combustion in a large-scale grate boiler",
abstract = "Grate furnaces are currently a main workhorse in large-scale firing of biomass for heat and power production. A biomass grate fired furnace can be interpreted as a cross-flow reactor, where biomass is fed in a thick layer perpendicular to the primary air flow. The bottom of the biomass bed is exposed to preheated inlet air while the top of the bed resides within the furnace. Mathematical modeling is an efficient way to understand and improve the operation and design of combustion systems. Compared to modeling of pulverized fuel furnaces, CFD modeling of biomass-fired grate furnaces is inherently more difficult due to the complexity of the solid biomass fuel bed on the grate, the turbulent reacting flow in the combustion chamber and the intensive interaction between them. This paper presents the CFD validation efforts for a modern large-scale biomass-fired grate boiler. Modeling and experiments are both done for the grate boiler. The comparison between them shows an overall acceptable agreement in tendency. However at some measuring ports, big discrepancies between the modeling and the experiments are observed, mainly because the modeling-based boundary conditions (BCs) could differ quite much with the conditions in the real furnace. Combustion instabilities in the fuel bed impose big challenges to give reliable grate inlet BCs for the CFD modeling; the deposits formed on furnace walls and air nozzles make it difficult to define precisely the wall BCs and air jet BCs that a reliable CFD needs. The CFD results show reasonably the mixing and combustion performance in the furnace based on the design drawings; while the measurement results reflect reliably the combustion performance in the real furnace in operation.",
keywords = "Biomass combustion, Grate boiler, Combustion instabilities, CFD, Water-cooled vibrating grate, CO2 emission",
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Yin, C, Rosendahl, L, Kær, SK, Sørensen, H, Clausen, S, Hille, T & Hvid, SL 2007, Modeling and experiments of biomass combustion in a large-scale grate boiler. in Proceedings of International Conference on Power Engineering. Springer, pp. 1173-1179, International Conference on Power Engineering 2007, Hangzhou, China, 23/10/2007.

Modeling and experiments of biomass combustion in a large-scale grate boiler. / Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen; Sørensen, Henrik; Clausen, Sønnik; Hille, Torben; Hvid, Søren L.

Proceedings of International Conference on Power Engineering. Springer, 2007. p. 1173-1179.

Research output: Contribution to book/anthology/report/conference proceedingArticle in proceedingResearchpeer-review

TY - GEN

T1 - Modeling and experiments of biomass combustion in a large-scale grate boiler

AU - Yin, Chungen

AU - Rosendahl, Lasse

AU - Kær, Søren Knudsen

AU - Sørensen, Henrik

AU - Clausen, Sønnik

AU - Hille, Torben

AU - Hvid, Søren L.

PY - 2007

Y1 - 2007

N2 - Grate furnaces are currently a main workhorse in large-scale firing of biomass for heat and power production. A biomass grate fired furnace can be interpreted as a cross-flow reactor, where biomass is fed in a thick layer perpendicular to the primary air flow. The bottom of the biomass bed is exposed to preheated inlet air while the top of the bed resides within the furnace. Mathematical modeling is an efficient way to understand and improve the operation and design of combustion systems. Compared to modeling of pulverized fuel furnaces, CFD modeling of biomass-fired grate furnaces is inherently more difficult due to the complexity of the solid biomass fuel bed on the grate, the turbulent reacting flow in the combustion chamber and the intensive interaction between them. This paper presents the CFD validation efforts for a modern large-scale biomass-fired grate boiler. Modeling and experiments are both done for the grate boiler. The comparison between them shows an overall acceptable agreement in tendency. However at some measuring ports, big discrepancies between the modeling and the experiments are observed, mainly because the modeling-based boundary conditions (BCs) could differ quite much with the conditions in the real furnace. Combustion instabilities in the fuel bed impose big challenges to give reliable grate inlet BCs for the CFD modeling; the deposits formed on furnace walls and air nozzles make it difficult to define precisely the wall BCs and air jet BCs that a reliable CFD needs. The CFD results show reasonably the mixing and combustion performance in the furnace based on the design drawings; while the measurement results reflect reliably the combustion performance in the real furnace in operation.

AB - Grate furnaces are currently a main workhorse in large-scale firing of biomass for heat and power production. A biomass grate fired furnace can be interpreted as a cross-flow reactor, where biomass is fed in a thick layer perpendicular to the primary air flow. The bottom of the biomass bed is exposed to preheated inlet air while the top of the bed resides within the furnace. Mathematical modeling is an efficient way to understand and improve the operation and design of combustion systems. Compared to modeling of pulverized fuel furnaces, CFD modeling of biomass-fired grate furnaces is inherently more difficult due to the complexity of the solid biomass fuel bed on the grate, the turbulent reacting flow in the combustion chamber and the intensive interaction between them. This paper presents the CFD validation efforts for a modern large-scale biomass-fired grate boiler. Modeling and experiments are both done for the grate boiler. The comparison between them shows an overall acceptable agreement in tendency. However at some measuring ports, big discrepancies between the modeling and the experiments are observed, mainly because the modeling-based boundary conditions (BCs) could differ quite much with the conditions in the real furnace. Combustion instabilities in the fuel bed impose big challenges to give reliable grate inlet BCs for the CFD modeling; the deposits formed on furnace walls and air nozzles make it difficult to define precisely the wall BCs and air jet BCs that a reliable CFD needs. The CFD results show reasonably the mixing and combustion performance in the furnace based on the design drawings; while the measurement results reflect reliably the combustion performance in the real furnace in operation.

KW - Biomass combustion

KW - Grate boiler

KW - Combustion instabilities

KW - CFD

KW - Water-cooled vibrating grate

KW - CO2 emission

M3 - Article in proceeding

SN - 978-3-540-76693-3

SP - 1173

EP - 1179

BT - Proceedings of International Conference on Power Engineering

PB - Springer

ER -

Yin C, Rosendahl L, Kær SK, Sørensen H, Clausen S, Hille T et al. Modeling and experiments of biomass combustion in a large-scale grate boiler. In Proceedings of International Conference on Power Engineering. Springer. 2007. p. 1173-1179