Computational fluid dynamic modeling of combustion and ash deposition in a biomass-cofired bubbling fluidized bed boiler

Biomass mixtures currently used in heat and power production are, despite their environmental and economical advantages, also combined with ash-related operational problems, such as slagging, fouling, and corrosion. To improve boiler efficiency, reliable ash deposition prediction is essential. In this work a computational fluid dynamic-based ash behavior prediction tool is used to model combustion and ash deposition tendencies in a 295-MW_t bubbling fluidized bed combustor fired with mixtures of peat and forest residue. Special focus is put on new modeling approaches for fuel distribution and the bubbling bed. The overall simulation results show good agreement with the conditions found experimentally in the boiler.