Circulating fluidised-bed combustion

A mathematical model for the steady-state combustion of char in a circulating fluidised bed (CFB) has been developed by taking into account the bed's hydrodynamic conditions, chemical-reaction rates, and combustion mechanism and the conservation of mass and energy. The model is an improvement over the simplified combustion model developed by Basu et al.1. The present model includes a fairly recent and important aspect of solid back-mixing as reported by Bolton and Davidson.2 Variation of bed density along the height of the combustor, as a consequence of this pheomenon, has also been considered. Kinetic data for the combustion reaction have been taken from Goldman et al.3 for anthracite char. The model is solved numerically by a computer program written in FORTRAN 77 and is executed in the mainframe IBM CPU model 3083. A CFB combustion system has been developed to obtain experimental data on combustion; the predictions obtained from the simulation show qualitative agreement with the limited amount of experimental data generated.