The hydrodynamic behaviour of a pulsed column

Directorate-General For Research And Innovation

Description

Industrial research and development

Sujets

• Sciences et techniques

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• Publié par: DIRECTORATE-GENERAL-FOR-RESEARCH-AND-INNOVATION
• Nombre de lectures: 135
• Langue: English
• Poids de l'ouvrage: 5 Mo

Extrait

Commission of the European Communities
nuclear science
and technology
The hydrodynamic behaviour
of a pulsed column Commission of the European Communities
The hydrodynamic behaviour
of a pulsed column
Gary Vassallo
JRC - Ispra Establishment
Directorate-General Science, Research and Development
1983 EUR 8597 EN Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Information Market and Innovation
Bâtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities
nor any person acting on behalf of the Commission
is responsible for the use which might be made
of the following information
Cataloguing data can be found at the end of this publication
Luxembourg, Office for Official Publications of the European Communities, 1983
ISBN 92-825-3688-2 Catalogue number:
© ECSC - EEC - EAEC, Brussels-Luxembourg, 1983
Printed in Italy Ill
ACKNOWLEDGEMENTS
The author is indebted to many for help received during
this work. He most gratefully acknowledges the invaluable
guidance and inspiration provided in this study by Prof. J.D.
Thornton of the Dept. of Chemical Engineering, Newcastle
University. Special acknowledgements for his help and
suggestions are given to Dr. H. Dwcrschak from the Engineering
Division under whose auspices the work was performed.
Dr. G. Gerber and Mr. J. De Roo from S.C.K./C.E.N., Mol,
Belgium deserve special citation for the use of their digital
analyser. Thanks are also extended to Mrs. G. Reid, Dr. B. Hunt,
Messrs. G. Volta and R. Gritti and to the workshops at C.C.R.
Ispra and Newcastle University.
The author is particularly grateful for the technical
expertise of Mr. G. Fiombo which has allowed the fabrication and
assembly of the experimental equipment at an exemplary level of
functionality and safety and permitted a large amount of data to
be collected in a relatively short time without any inconveni­
ences.
The author is sincerely grateful for the financial support
provided by the European Commission and the Student Research
Council and for assistance given by the administrative personnel
at Ispra.
Finally, the author wishes to thank Lieve for her capable
editing and support during the preparation of this manuscript. ν
TABLE OF CONTENTS
SUMMARY
1
1.0 INTRODUCTION 4
2.0 LITERATURE SURVEY 6
2.1 General Β
2.2 Dispersed-phase Holdup 9
2.3 Droplet Size 21
2.4 Backmixing8
3.0 SCOPE 39
3.1 General
3.2 Variables Studied
4.0 EXPERIMENTAL SECTION 41
4.1 Extraction System Employed
4.1.1 Calculation of experimental operating periods 42
4.1.2 Monitoring of TBP concentration in the organic
phase
4.1.3 Physical properties of extraction system 43
4.2 Experimental Equipment6
4.2.1 Pulse column description
4.2.2 Pulsing unit 48
4.2.3 Pumps and valves 51
4.2.4 Flowsheet
4.2.5 Safety4
4.2.6 Holdup equipment (shutter-plate device) 5
4.2.7 Photographic equipment
4.2.8 Backmixing tracer and equipment 6
4.3 Experimental Procedure5
4.3.1 General procedure 6
4.3.2 Dispersed-phase holdup measurements6
4.3.3 Droplet size measurements
4.3.4 Backmixing coefficients in the aqueous phase 67 VI
5.0 RESULTS AND DISCUSSION 68
5.1 Dispersed-phase Holdup 68
5.1.1 Axial variation of holdup 84
5.2 Droplet Size Measurements 86
5.2.1· Droplet size distributions 107
5.3 Continuous-phase backmixing 11 4
6.0 RECOMMENDATIONS FOR FURTHER WORK 1 2 6
7.0 CONCLUSIONS 1 28
NOMENCLATURE 1 31
REFERENCES 1 34
APPENDICES 1 42
A - Stagewise and Differential Backmixing Models 1 43
Β - Pendant Drop Technique 1 48
C - Distribution Coefficient of Lithium Nitrate
Between Nitric acid and Tri-butyl Phosphate 1 53
D - Dispersed-phase Holdup Data 1 54
E - Axial Holdup Data 1 63
F - Droplet Distribution Data - Probability
Densities 1 64
G - Axial Droplet Distribution Data - Probability
Densities 1 99
H - Determination of Backmixing Coefficients -
Method of Variances 204
I -Backmixing Data 208 VII
LIST OF FIGURES
1 Schematic Representation of Pulsed Column
Behaviour 8
2 Concentration Profile in a Column 29
3 Stainless-steel Cartridge 47
4 Pulsing Unit
5 Pulse Column / Pulsing Unit Connecting Tube 52
6 General View of Experimental Equipment3
7l Flow Diagram 55
8 Shutter-plate Device: View of Perforated-plates 5
9 Detail of the Shutter-plate Assembly8
10e Device9
11 Photographic Cell 60
12c Cell2
13 Effect of Frequency on Dispersed-phase Droplets 6
14t ofy and Amplitude on Holdup 7
15 Effect of Dispersed-phase Flowrate onp1
16t of Continuous-phase flowrate on Holdup
17 Effect ofe Flowrate onp4
18t of Dispersed-phasee on Holdup 75
19 Variation of xx with Dispersed-phase Flowrate6
20 Comparison between Experimental and Calculated
Values of Holdup 80
21 The Dependence of Vr° on af1
22 Limiting Values of Holdup as a Function of the
Flowrate Ratio3
23 Axial Variation of Holdup5
24 Effect of Frequency on Droplet Diameter 87
25t of Amplitude ontr8
26 Effect of Phase Flowrates on Droplet Diameter9
27 Variation of Droplet Diameter with Holdup 9
28n oftrhp1
29 d£ as a Function of (af)~1·2 94 VIII
30 d£ as a Function of (af)'0·75 96
31 d£ as an of (af)'0M7
32 Comparison between Experimental and Calculated
Values of d^ Based on Eq.(8l)9
33 Schematic Representation Showing Dependence of Vr
'on d^ 101
34 Variation of FP with d^2
35 Comparison between Experimental and Calculated
Values of d^ Based on Eq.(87) 104
36n betweenl andd
Values of d^ Based on Eq.(88)5
37 Characteristic Droplet Velocity as a Function of
Pulse Velocity and Holdup6
38 Influence of Increasing Frequency on the Droplet
Size Distribution8
39 Effect of Frequency on Droplet Size Distribution 109
40t of Amplitude ont Sizen 110
41 Effect of Flowrates on Droplet Sizen1
42 Variation of Droplet Size Distribution with
Plate Number 113
43 Typical Response Curves in Backmixing Experiments 116
44 Variation of Continuous-phaseg
Coefficient with Pulse Velocity 117
45n ofe Backmixing t with Flowrate of that Phase8
46 Variation ofeg
Coefficient with Dispersed-phase Flowrate 121
47 Comparison between Experimental and Calculated
Values of Continuous-phase Backmixing
Coefficient Based on Eq.(96) 123
48n betweenl andd
Values ofeg
Coefficient Based on Eq.(97)4
LIST OF TABLES
1 Densities of Chemical Solutions (kgm"3) 45
2 Calibration of Pulsing Unit 50
3 Variation of dL| with a and f 92