Mathematical Modelling of Biomass Combustion: Packing Conditions Issues

This article follows the authors’ previous works on numerical simulations of biomass drying and devolatilization (Juřena et al., 2009a-b), in which a packed bed of solid fuel particles is treated as a continuous porous medium. The bed model consists of several sub-models describing individual combustion processes. Since packing conditions change markedly during the processes, a proper description of all the phenomena related to it must be included as well. A mathematical model of wheat straw combustion in 1D experimental fixed-bed reactor is implemented into a computer program GRATECAL and effects of bed porosity change and particle volume shrinkage as two important packing conditions parameters are studied. The combustion includes drying, devolatilization and char oxidation. Results from simulations are shown and discussed.