A mathematical model for granulation kinetics

✍ Scribed by Andrzej Heim; Wojciech Antkowiak

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 945 KB
• Volume: 43
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(88)85136-4

✦ Synopsis

An equation for granulation kinetics has been derived on the basis of the mass balance of the material being granulated. The model presented takes into account mechanisms that cause a decrease in the mass of granuie-size groups, i.e. crushing and abrasion, and mechanisms which lead to an increase in size group mass, i.e. coalescence and layering. Considering a given group of size distributions, a rate of mass fraction growth was presented taking into account the influence of granules of both larger and smaller size. As a result a dependence describing the increase in the mass fraction of a size group has been obtained. The dependence contains three characteristic functions: a decrement rate function for a given size group, an agglomeration rate function, and a function of the growth rate of a given size group resulting from destroying large-size granules (grinding rate function). An experimental granulation of wet tine material in a drum has been performed. The obtained granule-size. distributions were approximated by a frequency function of gamma distribution. Theoretical size distributions were the basis for determining characteristic rate functions in a kinetic equation. As a result, all rate functions were described for each size group in the system during the whole granulation investigated. These functions completely described the kinetics of the granulation process. A comparison of real and theoretical distributions (determined on the basis of the model)obtained in subsequent periods of the process gives a good agreement of the model with the real run of the process.