(87c) Study of Residence Time Distribution in a Taylor-Couette Reactor

Study of residence time distribution
in a Taylor-Couette reactor

Haoyu Wang*, Anh Phan, Vladimir
Zivkovic, Kamelia Boodhoo

Chemical Engineering and Advanced Materials, Merz Court,
Newcastle University NE1 7RU Newcastle upon Tyne, United Kingdom.

*Haoyu.Wang@newcastle.ac.uk

The
flow between the gap of two differentially rotating concentric cylinders is
called Taylor-Couette (TC) flow. TC flow exhibits different flow regimes
(Taylor vortex flow, Wavy vortex flow, Modulated wavy vortex flow, Turbulent
Taylor vortex flow) as the rotational speed of the cylinder is increased (Figure 1). Residence time distribution (RTD) is an important parameter in reactor design
which characterizes the flow and mixing behavior of reaction components,
thereby influencing the selectivity in chemical reactions. Very few studies
have been reported on RTD characterization of TC flow, focusing primarily on
limited axial flow rates and rotational speed ranges where the Taylor vortex
flow regime is achieved^1,2. The present work aims to evaluate RTD across the whole spectrum of possible flow regimes in TC flow in order to provide a more comprehensive understanding of the mixing behavior inside a TC reactor.

The
experimental facility consists of two horizontally placed concentric cylinders of
300 mm in length and a gap of 10 mm between the cylinders (Figure 2). The outer Perspex cylinder (50 mm in diameter) is fixed and the inner cylinder (30 mm
diameter and made of 316 SS) rotates. The rotating speed of the inner cylinder
ranges from 0 to 1500 rpm. The working fluid, a mixture of water and glycerol, is
injected into one end of the device at different flow rates of up to 500 ml/min.
Pulse injection of the tracer KCI solution at the inlet is achieved by a
syringe pump. An E61M014 conductivity probe of 4 mm in diameter and 103 mm in
length that connects to a CDM210 conductivity meter is placed at the outlet of
the reactor for the measurement of conductivity of the working fluid. The
conductivity can be used to obtain the residence time distribution. Initial
experiments using pure de-ionized water indicate that the RTD profiles vary
between different flow regimes at the same axial flow rate highlighting the mixing
behavior in a TC reactor can alter from near-plug flow reactor to mixed flow
behavior as rotational speed increases. Further RTD results will be presented
and discussed in the context of the flow regime generated in the TC device.

Acknowledgements

The
authors would like to thank the European Union’s Horizon 2020 research and
innovation program for financial supports (grant agreement No 680565).

References

1.            Kataoka, K., Doi, H., Kongo, T. and Futagawa, M. (1975) 'Ideal Plug-Flow Properties
of Taylor Vortex Flow', Journal of Chemical Engineering of Japan, 8(6),
472-476.

2.            Pudjiono,
P.I., Tavare, N.S., Garside, J. and Nigam, K.D.P. (1992) 'Residence time
distribution from a continuous Couette flow device', The Chemical
Engineering Journal, 48(2), 101-110.

3.            Fenstermacher,
P.R., Swinney, H.L., Benson, S.V. and Gollub, J.P. (1979) 'Bifurcations to
periodic, quasiperiodi, and chaotic regimes in rotating and convecting fluids',
Annals of the New York Academy of Sciences, 316(1), 652-666.