Title:
Development and Validation of a Combined 1D-Fuel-Bed- and 3D-CFD-Model for the Simulation of Moving Grate Boilers
Author(s):
Barroso, G., Roth, S., Nussbaumer, T.
Document(s):
Paper
Abstract:
A combined extended 1D-fuel-bed- and 3D-CFD-model for the simulation of a moving grate wood chip furnace has been developed and validated with experiments. The extended 1D-fuel-bed-model (1D-EFBM) includes, among other things, “thick layer” treatment of the wood chip and fuel nitrogen. During the pyrolysis and the subsequent char gasification nitrogen species are emitted from the fuel bed depending on local temperature and excess air ratio, and on the fuel-nitrogen mass fraction. The temperature within a wood chip is considered inhomogeneous, due to the fact that the top layer of a wood chip interacts with the environment (radiation, convection, etc.). Therefore the temperature on the surface of the wood chip tends to be higher than the core temperature. For the pyrolysis, three competing reactions are considered: Direct gasification to light gases, to tar and light gases, and to char and light gases. The char is later gasified to CO and CO2, whereas the ratio depends on the local temperature regime in the fuel bed. The EDC combustion model is used in the subsequent 3D-CFD simulation with a reduced chemical mechanism. The fuel bed model can be used to predict the influence of operating parameters as e.g. moisture content, on fuel bed behaviour, wood gases production, and N-species production.
Keywords:
modelling, NOx reduction, moving grate boiler, fuel bed model, EDC, pyrolysis gas measurements
Topic:
Biomass Conversion Technologies for Heating, Cooling and Electricity
Subtopic:
Biomass and Bioliquids Combustion for Small and Medium Scale Applications
Event:
25th European Biomass Conference and Exhibition
Session:
2AO.5.1
Pages:
358 - 362
ISBN:
978-88-89407-17-2
Paper DOI:
10.5071/25thEUBCE2017-2AO.5.1
Price:
FREE
