Keywords

Biomass, Thermal conversion, Thermally thick, Modelling, CFD

Abstract

A one-dimensional model for the thermal conversion of thermally thick biomass particles is developed for the simulation of the fuel bed of biomass grate furnaces. The model can be applied for cylindrical and spherical particles. The particle is divided into four layers corresponding to the main stages of biomass thermal conversion. The energy and mass conservation equations are solved for each layer. The reactions are assigned to the boundaries. The model can predict the intra-particle temperature gradient, the particle mass loss rate as well as the time-dependent variations of particle size and density, as the most essential features of particle thermal conversion. When simulating the fuel bed of a biomass grate furnace, the particle model has to be numerically efficient. By reducing the number of variables and considering the lowest possible number of grid points inside the particle, a reasonable calculation time of less than 1 min for each particle is achieved. Comparisons between the results predicted by the model and by the measurements have been performed for different particle sizes, shapes and moisture contents during the pyrolysis and combustion in a single-particle reactor. The results of the model are in good agreement with experimental data which implies that the simplifications do not impair the model accuracy.

Original Publication Citation

Ramin Mehrabian, Selma Zahirovic, Robert Scharler, Ingwald Obernberger, Stefan Kleditzsch, Siegmar Wirtz, Viktor Scherer, Hong Lu, Larry L. Baxter, A CFD model for thermal conversion of thermally thick biomass particles, Fuel Processing Technology, Volume 95, 2012, Pages 96-108, ISSN 0378-3820, https://doi.org/10.1016/j.fuproc.2011.11.021.

Document Type

Peer-Reviewed Article

Publication Date

2011-12-24

Publisher

Elsevier

Language

English

College

Ira A. Fulton College of Engineering

Department

Chemical Engineering

University Standing at Time of Publication

Full Professor

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