Eulerian based population balance modeling of agglomeration in a bubbling fluidized bed combustor

Abstract

Renewable energy sources are contributing to the displacement of fossil fuel use for power generation and biomass combustion is a viable alternative for baseload power. Fluidized bed combustion (FBC) technology has become a favorable option for biomass (including industrial wastes) fired boilers for its benefits including fuel flexibility, high combustion efficiency, lower emissions (NO x , SO x ) in comparison to other solid fuel fired boilers. However, the variation of inorganic species and corrosive deposits lead to bed agglomeration resulting in unscheduled outages. In the present work, biomass combustion and bed agglomeration in a pilot scale atmospheric-fluidized bed combustor is simulated and analyzed. The Eulerian–Eulerian simulation is validated with the experimental data available in literature using a two-dimensional simplified geometry of a pilot scale fluidized bed combustor. Two each homogeneous and heterogeneous reactions are considered for devolatilization and char combustion processes during combustion with the species transport model. Population Balance Model (PBM) is implemented to calculate agglomerate hydrodynamics with air fed as fluidizing medium from the bottom of the combustor. The model results compared well and found consistent with available experimental data. Prediction of defluidization time of the bed showed a good agreement with the results of experiments.