Particle sized distribution simulation for an industrial fluidised bed urea granulator by PNB method considering non-uniform growth rate

ABSTRACT The present work is an extension of the PNB method. Contrary to the previous works, it is assumed that the growth rate of particles/granules is not constant along the granulator length and it depends on the granule mass flow rate and molten urea spray mass flowrate. With these assumptions, the governing equations were extracted, and the analytical solution was derived. Since this method is based on the particle number and the measured data are mass-based (defined based on mass fraction distribution), a general procedure was also proposed to transfer between number-based and mass-based quantities. Finally, the results were compared with measured data taken from a large-scale industrial urea granulator and close agreements were observed. This method is introduced as an effective tool for the simulation of other applications, like driers. GRAPHICAL ABSTRACT