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

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Abstrakt

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.
OriginalsprogEngelsk
TitelProceedings of International Conference on Power Engineering
Antal sider7
ForlagSpringer
Publikationsdato2007
Sider1173-1179
ISBN (Trykt)978-3-540-76693-3
ISBN (Elektronisk)978-3-540-76694-0
StatusUdgivet - 2007
BegivenhedInternational Conference on Power Engineering 2007 - Hangzhou, Kina
Varighed: 23 okt. 200727 okt. 2007

Konference

KonferenceInternational Conference on Power Engineering 2007
LandKina
ByHangzhou
Periode23/10/200727/10/2007

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Citationsformater

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. I Proceedings of International Conference on Power Engineering (s. 1173-1179). Springer.