Chapter 6
Dynamic Process Models for Fine
Grinding and Dispersing
Greta Fragnière, Ann-Christin Böttcher, Christoph Thon, Carsten Schilde,
and Arno Kwade
Abstract Fine grinding and dispersing, such as grinding in stirred media mills,
gains importance in several industrial processes. Solid materials processing is frequently subjected to dynamic changes, effecting the performance of milling. To
accurately model milling processes, dynamic flowsheet simulation turns out as a
promising approach to gain quick and reliable solutions, describing the milling process over time. The connection of different process units is even closer to the industrial
setup. Therefore, the focus of the study is the introduction of a dynamic model for
stirred media mills that can be implemented into flowsheet simulation. The modelling approach aims at separating grinding and transport phenomena in the mill.
Starting with an investigation of a batch grinding process in a “calibration mill”,
the dependency of the breakage rate on machine and material parameters is shown.
The stressing conditions in this calibration mill are determined theoretically and via
simulations using coupled CFD-DEM simulations. In the study, the prediction of
influences such as varying grinding media, stirrer speed and solids concentration on
the breakage rate worked out well. In continuous processes, the particle transport and
axial grinding media distribution, effecting the dynamics, are simulated as a series
of instantly mixed cells, connected by mixing streams. With the dynamic flowsheet
simulator Dyssol, the dynamic response of the product to changes in the feed was
compared to experimental investigations with limestone in a laboratory stirred media
mill. Material parameters for the model were tested in a newly designed breakage
tester.
G. Fragnière · A.-C. Böttcher · C. Thon · C. Schilde (B) · A. Kwade (B)
Institute of Particle Technology, Technische Universität Braunschweig,
Brunswick, Germany
e-mail: c.schilde@tu-braunschweig.de
A. Kwade
e-mail: a.kwade@tu-braunschweig.de
© Springer Nature Switzerland AG 2020
S. Heinrich (ed.), Dynamic Flowsheet Simulation of Solids Processes,
https://doi.org/10.1007/978-3-030-45168-4_6
199
Dynamic Process Models for Fine
Grinding and Dispersing
Greta Fragnière, Ann-Christin Böttcher, Christoph Thon, Carsten Schilde,
and Arno Kwade
Abstract Fine grinding and dispersing, such as grinding in stirred media mills,
gains importance in several industrial processes. Solid materials processing is frequently subjected to dynamic changes, effecting the performance of milling. To
accurately model milling processes, dynamic flowsheet simulation turns out as a
promising approach to gain quick and reliable solutions, describing the milling process over time. The connection of different process units is even closer to the industrial
setup. Therefore, the focus of the study is the introduction of a dynamic model for
stirred media mills that can be implemented into flowsheet simulation. The modelling approach aims at separating grinding and transport phenomena in the mill.
Starting with an investigation of a batch grinding process in a “calibration mill”,
the dependency of the breakage rate on machine and material parameters is shown.
The stressing conditions in this calibration mill are determined theoretically and via
simulations using coupled CFD-DEM simulations. In the study, the prediction of
influences such as varying grinding media, stirrer speed and solids concentration on
the breakage rate worked out well. In continuous processes, the particle transport and
axial grinding media distribution, effecting the dynamics, are simulated as a series
of instantly mixed cells, connected by mixing streams. With the dynamic flowsheet
simulator Dyssol, the dynamic response of the product to changes in the feed was
compared to experimental investigations with limestone in a laboratory stirred media
mill. Material parameters for the model were tested in a newly designed breakage
tester.
G. Fragnière · A.-C. Böttcher · C. Thon · C. Schilde (B) · A. Kwade (B)
Institute of Particle Technology, Technische Universität Braunschweig,
Brunswick, Germany
e-mail: c.schilde@tu-braunschweig.de
A. Kwade
e-mail: a.kwade@tu-braunschweig.de
© Springer Nature Switzerland AG 2020
S. Heinrich (ed.), Dynamic Flowsheet Simulation of Solids Processes,
https://doi.org/10.1007/978-3-030-45168-4_6
199