Using computational fluid dynamics for evaluating the pollutant formation in a biomass pellet burner

The following report contains a CFD analysis for determining the optimal design and operation of an existing grate burner prototype created in the Departamento de Ingeniería Mecánica at the Universidad Politécnica de Madrid. The current design consists of a combustion chamber and an antechamber, and is fed primary air from underneath the grate and secondary air horizontally over the pellet pile. A com- prehensive model of the prototype was created, consisting of three scales: the pellet scale, the pellet-pile scale, and the entire-burner scale. Considering each of these scales quasi-independently, the model was used to predict the outcome of different modifications on the operation and degisn. It was determined that CO and NOx emissions can be significantly reduced after certain modifications are made to how the existing burner is constructed and operated. The results of this study will be incorporated into future prototypes.