Determination of coalescence kernels for high-shear granulation using DEM simulations

Discrete element method (DEM) modeling is used in parallel with a model for coalescence of deformable surface wet granules. This produces a method capable of predicting both collision rates and coalescence efficiencies for use in derivation of an overall coalescence kernel. These coalescence kernels can then be used in computationally efficient meso-scale models such as population balance equation (PBE) models. A soft-sphere DEM model using periodic boundary conditions and a unique boxing scheme was utilized to simulate particle flow inside a high-shear mixer. Analysis of the simulation results provided collision frequency, aggregation frequency, kinetic energy, coalescence efficiency and compaction rates for the granulation process. This information can be used to bridge the gap in multi-scale modeling of granulation processes between the micro-scale DEM/coalescence modeling approach and a meso-scale PBE modeling approach.

[1]  A. A. Adetayo,et al.  A new approach to modeling granulation processes for simulation and control purposes , 2000 .

[2]  James D. Litster,et al.  Coalescence of deformable granules in wet granulation processes , 2000 .

[3]  Y. Tsuji,et al.  Discrete particle simulation of two-dimensional fluidized bed , 1993 .

[4]  P. C. Kapur.  Kinetics of granulation by non-random coalescence mechanism , 1972 .

[5]  P. Cundall,et al.  A discrete numerical model for granular assemblies , 1979 .

[6]  Bryan J. Ennis,et al.  Agglomeration and size enlargement session summary paper , 1996 .

[7]  S. Iveson,et al.  The dynamic strength of partially saturated powder compacts: the effect of liquid properties , 2002 .

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

[9]  J.A.M. Kuipers,et al.  Building population balance model for fluidized bed melt granulation: lessons from kinetic theory of granular flow , 2004 .

[10]  James D. Litster,et al.  Fundamental studies of granule consolidation Part 1: Effects of binder content and binder viscosity , 1996 .

[11]  P. C. Kapur,et al.  Coalescence Model for Granulation , 1969 .

[12]  S. Iveson,et al.  Limitations of one-dimensional population balance models of wet granulation processes☆ , 2002 .

[13]  Anders Rasmuson,et al.  High shear wet granulation modelling—a mechanistic approach using population balances , 2005 .

[14]  Douglas W. Fuerstenau,et al.  Size Distribution of Agglomerates in Coalescing Dispersed Phase Systems , 1970 .

[15]  D. Wolf,et al.  Force Schemes in Simulations of Granular Materials , 1996 .

[16]  Michael J. Hounslow,et al.  Tracer studies of high‐shear granulation: II. Population balance modeling , 2001 .

[17]  Douglas W. Fuerstenau,et al.  Mechanisms of agglomerate growth in green pelletization , 1973 .

[18]  Michael J. Hounslow,et al.  The Population Balance as a Tool for Understanding Particle Rate Processes , 1998 .

[19]  Ian T. Cameron.  Modern process modelling: Multiscale and goal-directed , 2004 .

[20]  Yoshitsugu Muguruma,et al.  Numerical simulation of particulate flow with liquid bridge between / particles simulation of centrifugal tumbling granulator , 2000 .

[21]  Ananth Annapragada,et al.  On the modelling of granulation processes: A short note , 1996 .

[22]  C. Thornton,et al.  A theoretical model for the stick/bounce behaviour of adhesive, elastic-plastic spheres , 1998 .

[23]  James D. Litster,et al.  Population balance modelling of granulation with a physically based coalescence kernel , 2002 .