Dynamic simulation of the particle size distribution in a circulating fluidized bed combustor

In the present work a particle population balance model for a circulating fluidized bed combustor (CFBC) is developed, that allows the description of the fate of individual particles in terms of attrition and transport effects. Operating conditions and the actual particle size distribution (PSD) are considered in the description of the shrinking of particles by attrition. Furthermore, a submodel has been developed, that takes into account the fact, that fresh particles have a higher attrition rate than particles which stayed for some time in the system and which therefore have been subjected to some stress already.The presented population balance model is able to describe the dynamic adjustment of the PSD in a given system. It has been validated with experimental data from a pilot-plant combustor, i.e. a CFBC with an inner diameter of 0.1 m and a height of 15 m. A comparison between experimental and calculated data shows the applicability of the model. In a second step the model has been applied to predict the effect of a load change and a change of the fuel, respectively, on the PSD inside the boiler and thus on the operating characteristics