(598a) Liquid-Liquid Mass Transfer In a Rotor-Stator Spinning Disc Reactor | AIChE

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(598a) Liquid-Liquid Mass Transfer In a Rotor-Stator Spinning Disc Reactor

Authors 

Visscher, F. - Presenter, Eindhoven University of Technology
van der Schaaf, J. - Presenter, Eindhoven University of Technology
de Croon, M. H. - Presenter, Eindhoven University of Technology
Schouten, J. C. - Presenter, Eindhoven University of Technology


Liquid-liquid mass transfer in a
rotor-stator spinning disc reactor

Frans
Visscher, John van der Schaaf, Mart de Croon, and
Jaap C. Schouten

Laboratory of Chemical Reactor
Engineering, Eindhoven University of Technology, The
Netherlands

Introduction

High gas-liquid and liquid-solid mass transfer rates
can be achieved in the rotor-stator spinning disc reactor (SDR) [1, 2]. Here we
demonstrate high liquid-liquid mass transfer rates in this new type of reactor
using the extraction of benzoic acid from n-heptane to water. A benzoic acid in
n-heptane flow was continuously contacted in the SDR with a benzoic acid free
water flow. The steady state benzoic acid concentrations in both liquids were
measured by UV-VIS spectroscopy. The experimental setup is shown in Figure 1.

 

11-04-19 Spinning disc opstelling artikel 1.png

Figure 1.
Schematic drawing of the rotor-stator spinning disc set-up.
The rotor is located at 1.0 10-3 m from the top and bottom stator.
Water is fed to the top of the reactor near the axis. n-Heptane
with benzoic acid is fed through an inlet in the bottom stator near the rim of
the disc.

Results

The overall liquid-liquid mass transfer coefficient, kLaLεORG,
was determined for a total volumetric liquid flow ranging from 4.5 10-6
m³ s-1 for an organic to aqueous ratio of 1:1, to 17.2 10-6
m³ s-1 at a ratio of 1:7. The multiphase flow pattern was determined
through high speed imaging of the bottom stator.

\My Documents\Activiteiten\AIChE 2011\Abstract LLE\2011-08-19 Abstract AIChE LLMT_files\image002.jpg

Figure 2. The influence of
rotational disc speed on the holdup inside the reactor. Pictures are
made through the bottom stator, with a total flow rate of 4.7
10-6 m³ s-1. Water appears blue because of water
soluble ink, n-heptane appears white.

Upon increasing the rotational disc speed the continues n-heptane spiral (in white) breaks up into
spiralling droplets due to the enlarged shear force that is present between the
rotor and the bottom stator. This causes an increase of the interfacial area.

2011-04-20 duplos aq 1.1 en 1.6.emf

Figure 3 The overall liquid-liquid mass transfer rates in the
rotor-stator spinning disc reactor are increasing with an increase of the rotor
speed and with the flow ratio. Values are calculated assuming plug flow
behavior for both phases.

2011-04-20 ideal 1 5 en 6.emf

Figure
4 At higher rotational disc speed, a stronger shear
stress is acting on the liquids between the rotor and the stator. This causes
an increase of the overall mass transfer coefficient. The overall liquid-liquid
mass transfer rates are calculated assuming ideally mixed behavior.

 

Conclusion

These liquid-liquid mass transfer rates are at least
25 times higher compared to those in packed columns, and at most 15 times
higher compared to mass transfer rates in state of the art microchannels. This
implies that both the process volume and the process time of current equipment
could be decreased.

 

References

[1]  Meeuwse,
et al. (2010) Chemical Engineering Science, 65(1), 466-471.

[2]  Meeuwse, et al. (2010)
Industrial & Engineering Chemical Research, 49(21),
10751-10757.

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