Discrete Simulation of Cenospheric Coal-Char Combustion

A phenomenological model of structural transformations during pulverized coal char combustion is presented. The random geometry of the voids is modeled realistically by means of a random assemblage of spheres in a spherical particle. Pore connectedness and growth are accounted for as the combustion proceeds. The percolation behavior of the void space is dramatically demonstrated. The effects of different initial void fractions and of the random nature of the structure itself, at a given initial void fraction, are shown. This sheds some light on our ability to realistically model the solid. The limitation of shrinking core models of combustion of cenospheric chars are demonstrated. In this initial application, the model is limited to isothermal combustion with no diffusional limitations.