Modelling of coal particle combustion in fluidized bed

In the article the analysis of issues of modelling of coal particle combustion in a fluidized bed was carried out. Moreover, the results of the validation of a new proposition of a mathematical model of single char particle combustion in a fluidized bed were presented in the paper. This model takes account of the mass loss resulting from the contact of the bed particle with the surface of a burning char particle. In the opinion of many authors, the contact of inert material with a char particle causes their fragmentation which in some conditions of combustion and hydrodynamics of bed leads to the elutriation of unburnt fine particles from the combustion chamber increasing the incomplete loss of combustion. During the model validation the mechanical coal properties i.e. Vickers hardness and fracture toughness were taken into account as presented in [2]. The wide range of experimental tests, on which basis of which the model validation allowed the determination of the possibility of the model application to predict a combustion rate in fluidized bed conditions, as well as the contribution of the erosion process to the total mass loss. It also indicated that the main reason for combustion intensification in the fluidized bed is the clearance (elimination) of ash from the surface of the burning char and the increase of mass transfer coefficient in the particle region.