Granule size distribution for a multi-chamber fluidized-bed melt granulator: Modeling and validation using process measurement data

Abstract In this work, a steady-state model of a multi-chamber fluidized-bed granulator used for urea production is developed and validated. To this aim, mass, energy and population balances are solved for all the fluidized beds. Regarding the population balance equation (PBE), pure coating or the combined mechanisms of coating and elutriation are taken into account. Both PBE formulations are analytically solved and a new solution methodology is proposed to handle inlet solid streams distributed in different size grids and to minimize the solution errors propagation expected when a set of PBEs in series has to be solved. By comparison with experimental data, it is found that the model including coating and elutriation gives a better representation of the particles size distribution with respect to the results found when pure coating is assumed. Besides, the results indicate that the fines are removed almost completely in the first and second chambers, being the amount of fines in the subsequent chambers negligible.

[1]  Juliana Piña,et al.  Analysis of the product granulometry, temperature and mass flow of an industrial multichamber fluidized bed urea granulator , 2011 .

[2]  Francis J. Doyle,et al.  Identification of models for control of wet granulation , 2009 .

[3]  Alfonso M. Albano.  Mathematical Methods: for Students of Physics and Related Fields , 2000 .

[4]  Shamsul Qamar,et al.  Numerical solution of population balance equations for nucleation, growth and aggregation processes , 2007, Comput. Chem. Eng..

[5]  Stefan Heinrich,et al.  Chapter 2 Fluidized bed spray granulation , 2007 .

[6]  Ian T. Cameron,et al.  Steady state modelling and simulation of a fertilizer granulation circuit , 1995 .

[7]  Achim Kienle,et al.  A numerical bifurcation analysis of continuous fluidized bed spray granulation with external product classification , 2006 .

[8]  L. Marmo,et al.  Predicting the pressure drop across the solids flow rate control device of a circulating fluidized bed , 2006 .

[9]  Joachim Werther,et al.  Design specifications in the flowsheet simulation of complex solids processes , 2009 .

[10]  Joachim Werther,et al.  The ultimate goal of modeling—Simulation of system and plant performance , 2011 .

[11]  Ivana M. Cotabarren,et al.  Analysis of Optimal Control Problems and Plant Debottlenecking for Urea Granulation Circuits , 2011 .

[12]  Ian T. Cameron,et al.  A multi-form modelling approach to the dynamics and control of drum granulation processes , 2007 .

[13]  Kersten Christoph Link,et al.  Fluidized bed spray granulation: Investigation of the coating process on a single sphere , 1997 .

[14]  Ian T. Cameron,et al.  Performance assessment and model validation for an industrial granulation circuit , 2007 .

[15]  D. S. Yan,et al.  Mineral Processing Design and Operation: An Introduction , 2006 .

[16]  W. Pietsch.  Size enlargement by agglomeration , 1991 .

[17]  Michael J. Hounslow,et al.  Kinetics of fluidised bed melt granulation I: The effect of process variables , 2006 .

[19]  Octave Levenspiel,et al.  Elutriation from fluidized beds , 1984 .

[20]  Vittorio Betta,et al.  A study of streams of solids flowing from solid-gas fluidized beds , 1961 .

[21]  James D. Litster,et al.  The Science and Engineering of Granulation Processes , 2004 .

[22]  A. W. Vreman,et al.  A basic population balance model for fluid bed spray granulation , 2009 .

[23]  Joachim Werther,et al.  Fluidized bed spray granulation: Analysis of the system behaviour by means of dynamic flowsheet simulation , 2010 .

[24]  Terence Allen,et al.  Powder Sampling and Particle Size Determination , 2003 .

[25]  Francis J. Doyle,et al.  Model predictive control of a granulation system using soft output constraints and prioritized control objectives , 2001 .