Computer Simulation of Fluidized Bed Granulation by a Two-Dimensional Random Coalescence Model

Computer simulation of granulation in a fluidized bed process was carried out using a two-dimensional random coalescence model, In this contribution, seed circles of two sizes were granulated by circular spray mist with radii obeying log-normal distribution on the basis of adhesion probability, in which the adhesion force of spray mist was taken into consideration. This simulation was then applied to fluidized bed granulation, in which a 7:3 weight ratio mixture of lactose and corn starch was granulated by an aqueous solution of hydroxypropylcellulose of several concentrations. Effects of moisture content and spray mist size on geometric median diameter of granules were investigated experimentally and analytically. It was found that granulation phenomena, in which granule growth progressed with an increase in moisture content and spray mist size, were very well simulated by the model proposed, thereafter, the mechanism of particle adhesion in fluidized bed granulation was elucidated.