Mathematical modeling of coal conversion processes with application to atmospheric fluidized bed combustion

The main goal of the present thesis is to develop mathematical models for coal conversion processes, to improve the understanding of the underlying physical processes and to support the experimental work in the fieId. Therefore, emphasis is given on developing analytical descriptions for variables involved with conversion of solid particlesin a gas. The analytical solutions are applied to describe a number of particle conversion processes which are of interest to a fluidized bed combustor: i.e. char combustion, NOx-char reduction and sulfation of limestone particles. The solutions are implemented in an overall reactor model of a fluidized bed combustor thus enabling the assessment of the overall process parameters on the basis of coal properties established by micro-scale experiments.