Vertical arrangement of SRF particles in a stationary fluidized bed

Abstract

Flexibility against fuel properties makes Fluidized Bed Conversion a markedly successful technology also for climate change mitigation. Solid Recovered Fuel is a standardized waste-derived fuel of inherently inhomogeneous character regarding particle size, shape, and composition. It is a crucial question, how much of these particles can utilize the advantages of the FBC technology, that is, how much of them will be located in the bed body – instead of floating to the top or sinking to the bottom. The bed-frozen method was used in this research, and the relative weight, concentration, density, and size distribution of the particles found at the three vertical locations were measured. Relative fluidization velocity and bed particle mean diameter were varied as independent variables. A bi-directional segregation phenomenon was observed on an area of the space spanned by the independent variables, and a region of safe and robust operation was recognized as well. A successive change can be observed between the two extremes of these areas regarding total mass, concentration, and size distribution of the particles found in the three referred vertical locations. Densities of the SRF particles alone do not explain the measured vertical arrangements.