130
H. Rehage and M. Kind
compares the dynamic semi-batch simulation to experimental data and, furthermore,
investigates the influence of dynamic process parameters on the product PSD.
3.1 Steady-State Precipitation
The experiments and simulations of Setup A aim at validating our steady-state model
for CIJM precipitation and investigating its predictiveness towards the PSD. In addition to the micro mixing model by Metzger and Kind [4], two other models by [24,
33] are compared, which are not explicitly discussed in Sect. 2.3.1.2.
As shown in Fig. 15, the median of the volume-based PSD (L 50,3 ) for precipitated
particles in Setup A experiments can be well-predicted with a steady-state precipitation model using the micro mixing model by Metzger and Kind [4]. Interestingly, the
model by Bałdyga and Bourne [24] predicts larger particles compared to the other
mixing models. We could furthermore show by mathematical analysis that the models by Metzger and Kind [4] and Schwarzer [33] do not implement the engulfment
theory correctly. Both models proved to be suitable for our simulations but should
be designated as empirical models.
We, furthermore, investigated the influence of recycle streams on steady-state
precipitation by Setup B experiments and simulations. As observable in Fig. 16,
the PSD becomes increasingly multimodal with increasing splitting factor β. This
multimodality is caused mostly by recycled particles passing the CIJM more often
and, therefore, growing more than particles passing the CIJM only once. Furthermore,
the size of the smallest particles in the first peak, which are the particles after a single
precipitation in the CIJM, is also increased for β ≥ 0.1 in a nonlinear way (Fig. 16).
Fig. 15 Median of
volume-based PSD (L 50,3 )
versus jet velocity with for
simulations with different
micro mixing models by [24,
33, 4] and experiments.
Particle size measured by
DLS
2
4
6
8
10
12
14
16
40
60
80
100
120
140
L
50,3 (nm)
u jet (m
1 s
-1
)
100
1000
10000
(W
1 kg
-1 )
Baldyga
Schwarzer
Metzger
Experiment
H. Rehage and M. Kind
compares the dynamic semi-batch simulation to experimental data and, furthermore,
investigates the influence of dynamic process parameters on the product PSD.
3.1 Steady-State Precipitation
The experiments and simulations of Setup A aim at validating our steady-state model
for CIJM precipitation and investigating its predictiveness towards the PSD. In addition to the micro mixing model by Metzger and Kind [4], two other models by [24,
33] are compared, which are not explicitly discussed in Sect. 2.3.1.2.
As shown in Fig. 15, the median of the volume-based PSD (L 50,3 ) for precipitated
particles in Setup A experiments can be well-predicted with a steady-state precipitation model using the micro mixing model by Metzger and Kind [4]. Interestingly, the
model by Bałdyga and Bourne [24] predicts larger particles compared to the other
mixing models. We could furthermore show by mathematical analysis that the models by Metzger and Kind [4] and Schwarzer [33] do not implement the engulfment
theory correctly. Both models proved to be suitable for our simulations but should
be designated as empirical models.
We, furthermore, investigated the influence of recycle streams on steady-state
precipitation by Setup B experiments and simulations. As observable in Fig. 16,
the PSD becomes increasingly multimodal with increasing splitting factor β. This
multimodality is caused mostly by recycled particles passing the CIJM more often
and, therefore, growing more than particles passing the CIJM only once. Furthermore,
the size of the smallest particles in the first peak, which are the particles after a single
precipitation in the CIJM, is also increased for β ≥ 0.1 in a nonlinear way (Fig. 16).
Fig. 15 Median of
volume-based PSD (L 50,3 )
versus jet velocity with for
simulations with different
micro mixing models by [24,
33, 4] and experiments.
Particle size measured by
DLS
2
4
6
8
10
12
14
16
40
60
80
100
120
140
L
50,3 (nm)
u jet (m
1 s
-1
)
100
1000
10000
(W
1 kg
-1 )
Baldyga
Schwarzer
Metzger
Experiment