A Detailed Study of a Multi-MW Biomass Combustor by Numerical Analysis: Evaluation of Fuel Characteristics Impact

In the recent years the interest toward the use of biomass as a fuel for energy conversion purposes has been growing. In parallel, the continuous tightening of regulations led to the improvement of accurate design techniques, in order to optimize the combustion process and simultaneously control pollutant emissions. In this scenario, a study based on a 3D Computational Fluid Dynamics approach of an existing 50MWth biomass fixed-bed combustion furnace is presented, fuelled by grape marc. A solver based on OpenFOAM has been used and modified, with special regard to the treatment of bed evolution by means of a mixed Lagrangian-Eulerian scheme. In particular, the fully 3D approach here presented, directly solves both bed and freeboard. Special care has also been devoted to the treatment of radiating fluxes, having a remarkable influence on the bed evolution. Results have been compared to experimental data in terms of temperature showing a good agreement. Further comparisons have been done with literature available data for a similar power size biomass furnace showing reasonable similarities.