Handbook of Laboratory Distillation, With an Introduction to Pilot Plant Distillation (Techniques & Instrumentation in Analytical Chemistry)

525 Pages·1981·23.98 MB·English

by  Erich Krell

TECHNIQUES AND INSTRUMENTATION IN ANALYTICAL CHEMISTRY - VOLUME 2
Handbook
of Laboratory Distillation
With an Introduction to Pilot Plant Distillation
TECHNIQUES AND INSTRUMENTATION IN ANALVTICAL CHEMISTRY
Volume 1 Evaluation and Optimization of Laboratory Methods
and Analytical Procedures. A Survey of Statistical
and Mathematical Techniques
by D. L. Massart, A. Dijkstra and L. Kaufman
Volume 2 Handbook of Laboratory Distillation
by E. Krell
-
TECHNIQUES AND INSTRUMENTATION IN ANALYTICAL CHEMISTRY VOLUME 2
Handb ook
of Laboratory Distillation
With an Introduction to Pilot Plant Distillation
Completely revised second edition
Erich Krell
Akademie der Wissenschaften der DDR
Zentralinstitut fur Isotopen- und Strahlenforschung, Leipzig
Translation, exclusive of the parts retained from the 1st
English edition as prepared by C. G. Verver, Amsterdam,
by Dr. phil. Manfred Hecker, Leipzig.
E LSEVl ER SCI E NTI FIC P U BLI S H ING COMPANY
-
-
Amsterdam Oxford NewYork 19 82
Publish& in co-edition with
VEB Deutmher Verlag der Wissenechaftan, Berlin
Dietribntion of thie book is being handled by the following publishers
for the E.S.A. and Canada
Elsevim North-Holland, Inc.
62 Vanderbilt Avenue
NewYwk, NY 10017
for all remaining areas
Eleevier Scientific Publishing Company
1 Molenwerf
P.O. Box 211, loo0 AE Amsterdam, The Netherlands
Lisray ef Congress Cataloging in Publication Data
Krell, Erich.
Handbook of laboratory distillation.
(Techniques and instrumentation in analytical
chemistry ; v. 2)
Trsnslation of: 3., bearb. und em. Ad. Handbuch
der Laboratoriumedestille,tion.
Bibliography: p.
Includes index.
1. Di~~t~~8tion-hboratmoarnyu ale. I. Title.
II. Series.
QD63.D8K713 1982 542l.4 82-9855
ISBN 0-444-99523-7 AACR2
@ VEB Deutscher Verlag der Wissenechaften, Berlin, 1982
All rlghts reserved. No part of this publication may be reproduced, stored in a
ret,rieval system, or transmitted in any form or by any means electronic, mechan-
ical, photocopying, recording, or otherwise, without the prior written permission of
the publisher.
Printed in the German Democratic Republic
Foreword to the third edition
The first edition of 1958 was sold out in a relatively short time. The second edi-
tion followed in 1960. The book has become a standard work and has been translated
into Russian, English and Hungarian.
This edition has again been written with the object of giving an account of the
subject of laboratory distillat)ion including recent views and developments. The
literature has been reviewed up to the year 1979. The author has adopted the course
of dealing only with generally accepted facts ; there are still numerous problems in sim-
ple and countercurrent distillation which have not yet been completely clarified and
in which there exist differences of opinion among various investigators. Distinct
trends in development have nevertheless been mentioned, in order to give an incentive
for further work. Owing to the large mass of material, a critical selection has been
necessary. An attempt has been made to introduce the mathematical deductions
and formulae required in laboratory work in a readily understandable form. Readers
with a mathematical turn of mind and those interested in particular problems will
find extensive references to the literature for further study.
The fundamental scheme of arrangement as applied in the first edition has
been retained. Section 5.1.3 has been extended to cover pilot plant distillation.
Section 4.2 now deals with fluidand interface dynamics. Chapter 8 could be drastically
shortened as there are a variety of components of distillation apparatus and the
pertaining measuring and control devices commercially available. The nomograms,
which were presented separately, have been inserted in the text. The references
for the various chapters have been rearranged and important new items added
to them. A great number of review articles serve to provide coinprehensive lists
of references for a longer period.
The book is intended primarily for physicists, chemists and engineers engaged in
chemical industry and in research or development centres, whose work includes
distillation on a laboratory or semi-technical scale. It will, however, also be useful
to undergraduates, chemical technologists and laboratory assistants as a source
of answers to inany questions in the field of practical distillation and separating
processes. It is hoped that it will prove a guide to better and inore economi-
cal methods of operation for all these who have to carry out distillation in the
laboratory.
The author wishes to express his special gratitude to Prof. Dr. habil. K1. Wetzel
for his interest in the book, his valuable suggestions and constant support. He also
wishes to thank Dr. H. Stage and E. Giebeler for the numerous helpful comments
they have made. Further his thanks are due to the various manufacturers of labor-
atory apparatus and glassware who have provided him with prospectuses and
6 Foreword to the third edition
technical data. Last but not least, he is grateful to the publishers for t,he generous
lay-out of the book, in particular to the staff of the chemistry department for their
thorough work on the manuscript.
It is to be hoped that this third edition will also contribute to the further develop-
ment of laboratory distillation and that, in laboratories, in industry, in technical
schools and universities, it will serve as a textbook and as a guide in the solution
of problenls of separation by distillation.
Dr.-Ing. Erich Krell
Akademie der Wissenschaften der DDR
Zentralir~et~itufut r Isotopen- und Strahlenforschung, Leigzig
Contents
List of symbols . . . . . . . . . . . . . . . . . . . . . . . . . . 11
.
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
.
a A review of the history of laboratory distillation . . . . . . . . . . . . 20
.
3 Standardization and data on concentrations. . . . . . . . . . . . . . 32
3.1 Standardization of distillation appqatus . . . . . . . . . . . . . . . 32
3.2 Definition of concepts . . . . . . . . . . . . . . . . . . . . . . . . 37
3.3 Symbols and units . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.4 Definitions and conversion of concentrations . . . . . . . . . . . . . . 38
.
4 Physical fundamentals of the separation process . . . . . . . . . . . . 43
4.1 Principles of simple and countercurrent distillation . . . . . . . . . . 43
4.2 Fluid and interface dynamics . . . . . . . . . . . . . . . . . . . . 46
4.2.1 Wetting columns . . . . . . . . . . . . . . . . . . . . . . . . . . 46
4.2.2 Film formation . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
4.2.3 Column dynamics . . . . . . . . . . . . . . . . . . . . . . . . . 55
4.3 Miscibility of the components . . . . . . . . . . . . . . . . . . . . 65
4.4 Vapour pressure-temperature relationship. p - t . . . . . . . . . . . . 58
4.4.1 Measurement of saturated vapour pressures . . . . . . . . . . . . . . 59
4.4.2 Calculation and representation of saturated vapour pressures . . . . . . . 66
4.5 Equation of state and ps-diagrams . . . . . . . . . . . . . . . . . . 76
4.6 Boiling point diagram, B - 2, equilibrium curve. y* - x . . . . . . . 80
4.6.1 Calculation of vapour-liquid equilibria . . . . . . . . . . . . . . . . 82
4.6.2 Volatility, separation factor oc and activity coefficient y . . . . . . . . . 57
4.6.3 The experimental determination of equilibrium curves . . . . . . . . . 91
4.7 Number of theoretical plates (separat)ings tages) . . . . . . . . . . . . 102
4.7.1 Calculation of separating stages by the McCabe-Thiele method in batch
operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
4.7.2 Calculation of separating stages by the McCabe-Thiele method in contin-
uous distillation . . . . . . . . . . . . . . . . . . . . . . . . . . 111
4.7.3 Determination of separating stages by the McCabe-Thiele method for
equilibrium curves with an inflection point or an azeotropic point . . . . 1 15
4.7.4 Determination of separating stages for flat equilibrium curves and for
equilibrium curves close to operating line . . . . . . . . . . . . . . . 117
4.7.5 Methods for determining the plate number in batch distillation arithmet-
ically . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
8 Contents
4.7.5.1 Determination of the plate number from difference in boiling point . . . . 1 20
4.7.5.2 Calculation of the plate number with the aid of the fractionating factor
and the Rose formulae . . . . . . . . . . . . . . . . . . . . . . . 121
4.7.5.3 Calculation of the minimum plate number by the Fenske equation for
ideal mixtures and w = ca . . . . . . . . . . . . . . . . . . . . . 125
4.7.5.4 Other methods and comparieon . . . . . . . . . . . . . . . . . . . 127
4.8 Theory of packed columns . . . . . . . . . . . . . . . . . . . . . . 128
4.8.1 Process of separation in a packed column . . . . . . . . . . . . . . . 1 28
4.8.2 Determination of the transfer unit. TU . . . . . . . . . . . . . . . .1 32
4.8.3 Intensity of countercurrent exchange; time required . . . . . . . . . . 1 36
4.9 Determination of t.h e number of plates and transfer units in the batch
and continuous separation of multicomponent mixtures . . . . . . . . . 1 40
4.10 Testing plate columns and packed columns . . . . . . . . . . . . . . 144
4.10.1 Column diameter . . . . . . . . . . . . . . . . . . . . . . . . . 146
4.10.2 Effective separating length; the introduction of column packing . . . . . 1 46
4.10.3 Test mixtures end the composition of the charge . . . . . . . . . . . . 1 50
4.10.4 Reflux ratio and quantity of reflux . . . . . . . . . . . . . . . . . . 1 62
4.10.5 Total. static and operating hold-up . . . . . . . . . . . . . . . . . . 167
4.10.6 Operating presaure . . . . . . . . . . . . . . . . . . . . . . . . . 159
4.10.7 Load and vapour velocity . . . . . . . . . . . . . . . . . . . . . . 160
4.10.8 Method of column calibration . . . . . . . . . . . . . . . . . . . . 162
4.10.9 Data for packed and plate columns . . . . . . . . . . . . . . . . . . 166
4.11 Pressure drop. limiting velocity and calculation of column dimensions . . . 1 67
4.13 Heat calculations . . . . . . . . . . . . . . . . . . . . . . . . . 182
4.13 Distillate properties and distillation diagrams . . . . . . . . . . . . . 187
4.14 htructions for the oalculation of distillation conditions . . . . . . . . . 1 93
4.14.1 Batch distillation at atmospheric pressure . . . . . . . . . . . . . . . 1 93
4.14.2 Continuous distillation . . . . . . . . . . . . . . . . . . . . . . . 197
4.14.3 Vacuum distillation . . . . . . . . . . . . . . . . . . . . . . . . 198
4.16 Diatillation calculations by computer . . . . . . . . . . . . . . . . . 1 98
.
(i Separating processes . . . . . . . . . . . . . . . . . . . . . . . . 203
6.1 The scale of operation . . . . . . . . . . . . . . . . . . . . . . . . 203
6.1.1 Nicro- and semi-micro-distillation . . . . . . . . . . . . . . . . . .2 03
5.1.2 Analytical distillation . . . . . . . . . . . . . . . . . . . . . . . 210
5.1.3 Preparative and production distillation . . . . . . . . . . . . . . . . 2 14
5.1.3.1 Semi-technical columns . . . . . . . . . . . . . . . . . . . . . . . 215
6.1.3.2 Pilotplants . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
5.1.3.3 The preparation of distilled water . . . . . . . . . . . . . . . . . . 2 25
5.1.4 The separation of isotopes . . . . . . . . . . . . . . . . . . . . . . 228
5.1.4.1 Isotope separation by low-temperature countercurrent distillation . . . . 2 31
5.1.4.2 The preparation of D, and lSO, by countercurrent distillation of water 232
5.1.4.3 The preparation of various isotopes . . . . . . . . . . . . . . . . .2 42
5.2 Methods of operation . . . . . . . . . . . . . . . . . . . . . . . . 244
5.2.1 Batch and semi-continuous distillation . . . . . . . . . . . . . . . .2 45
5.2.2 Continuous distillation . . . . . . . . . . . . . . . . . . . . . . . 246
5.2.2.1 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
6.2.2.2 Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249
Contents 9
5.2.2.3 Apparatus for continuous column distillation . . . . . . . . . . . . . . 2 50
5.2.2.4 Examples of application from laboratory practice . . . . . . . . . . . . 2 54
5.2.2.3 Starting up continuous distillations . . . . . . . . . . . . . . . . . . 2 55
5.2.3 Separation by partial condensation . . . . . . . . . . . . . . . . . . 2 56
5.3 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
5.3.1 Low-temperature distillation . . . . . . . . . . . . . . . . . . . . . 260
5.3.2 High-temperature and isothermal distillation . . . . . . . . . . . . . . 2 69
5.4 Distillation pressure . . . . . . . . . . . . . . . . . . . . . . . . 274
5.4.1 Simple and countercurrent distiHction under reduced pressure . . . . . . 2 74
5.4.2 Continuous equilibrium vaporisation (flash distillation) . . . . . . . . . 2 80
5.4.3 Thin-film distillation . . . . . . . . . . . . . . . . . . . . . . . . 283
5.4.4 Molecular distillation . . . . . . . . . . . . . . . . . . . . . . . . 292
5.4.5 Pressure distillation . . . . . . . . . . . . . . . . . . . . . . . . . 305
.
6 Selective separating processes . . . . . . . . . . . . . . . . . . . . 307
6.1 Carrier vapour distillation . . . . . . . . . . . . . . . . . . . . . . 307
6.2 Szeotropic and extractive distillation . . . . . . . . . . . . . . . . . 3 12
6.2.1 dzeotropic distillation . . . . . . . . . . . . . . . . . . . . . . . . 317
6.2.2 Extractive distillation . . . . . . . . . . . . . . . . . . . . . . . . 327
6.3 Solution distillation and special methods . . . . . . . . . . . . . . . 334
.
7 Constructional materials and apparatus . . . . . . . . . . . . . . . . 336
7.1 Const.r uctional materials for distillation apparatus . . . . . . . . . . . 336
7.2 Standard apparatus and unit parts . . . . . . . . . . . . . . . . . . 3 37
7.2.1 Taps and valves . . . . . . . . . . . . . . . . . . . . . . . . . . 344
7.3 Columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
7.3.1 Empty columns . . . . . . . . . . . . . . . . . . . . . . . . . . 347
7.3.2 Packed columns . . . . . . . . . . . . . . . . . . . . . . . . . . 366
7.3.3 Plate columns . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
7.3.4 Columns with stationary elements . . . . . . . . . . . . . . . . . . 3 65
7.3.5 Columns with rotating elements . . . . . . . . . . . . . . . . . . . 373
7.4 Condensers and dephlegmators . . . . . . . . . . . . . . . . . . . . 382
\
7.5 Adapters; still and column heads . . . . . . . . . . . . . . . . . . 387
7.5.1 Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
7.5.2 Still heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
7.5.3 Column heads . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
7.6 Still pots. receivers and fraction collectors . . . . . . . . . . . . . . . 3 98
7.6.1 Still pots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
7.6.2 Receivers and fraction collectors . . . . . . . . . . . . . . . . . . . 401
7.7 Insulation and heating devices . . . . . . . . . . . . . . . . . . . . 405
7.7.1 The heating of still pots and flasks . . . . . . . . . . . . . . . . . . 4 05
7.7.2 The heating of feed-stock and bottom . . . . . . . . . . . . . . . . . 4 10
7.7.3 Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412
7.8 Packings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
7.8.1 Shape of packing units . . . . . . . . . . . . . . . . . . . . . . . 420
7.8.2 Constructional material of pnckings . . . . . . . . . . . . . . . . . . 427