Table Of ContentE. Stahl· K.-W Quirin· D. Gerard
Dense Gases
for Extraction
and Refining
Translation from the German Edition
by M. R. F. Ashworth
With 107 Figures and 46 Tables
Springer-Verlag Berlin Heidelberg NewY ork
London Paris Tokyo
t
Prof. Dr. Egon Stahl
D-6930 Eberbach, Friedrich-Ebert-Slr. 29
Dr. Karl-Werner Quirin
D-6638 Dillingen, Dr. Prior-Str. 48
Dr. Dieter Gerard
D-6639 Rehlingen, Lothringer Str. 12
Translator:
Professor Dr. M. R. F. Ashworth
Universitat des SaarI andes
Organische und Instrumentelle Analytik
D-6600 Saarbriicken
ISBN-13 : 978-3-642-72894-5 e-ISBN-13 : 978-3-642-72892-1
DOl: 10.1007/978-3-642-72892-1
Library of Congress Cataloging-in-Publication Data
Stahl, E. (Egon)
[Verdichtete Gase zur Extraktion und Raffination. English] Dense gases for extraction
and refining / E. Stahl. K. W. Quirin, D. Gerard; translated from the German edition
by M. R. F. Ashworth. p. cm. Translation of: Verdichtete Gase zur Extraktion und Raffi
nation. Bibliography: p. Includes index.
ISBN-13 :978-3-642-72894-5 (U.S.)
I. Gas extraction. I. Quirin, K. W. (Karl-Werner). 1952-II. Gerard, D. (Dieter), 1954-
III. Title.
TP156.E8S7313 1987
665.7'3--dc 19
This work is subject to copyright. All rights are reserved, whether the whole or part
of the material is concerned, specifically the rights of translation, reprinting. re-use of
illustrations, recitation, broadcasting, reproduction on microfilms or in other ways,
and storage in data banks. Duplication of :his publication or parts thereof is only
permitted under the provisions of the German Copyright Law of September 9, 1965,
in its version of June 24, 1985, and a c0p.yright fee must always be paid. Violations fall
under the prosecution act of the German Copyright Law.
© Springer-Verlag Berlin Heidelberg 1988
Softcover reprint of the hardcover 1st edition 1988
The use of registered names, trademarks, etc. in this publication does not imply, even
in the absence of a specific statement, that such names are exempt from the relevant
protective laws and regulations and therefore free for general use.
2152/3020-543210
Foreword
Dense gases possess dissolving properties for lipophilic compounds which can be
utilised for substance extraction and fractionation. This has been known for a long
time but it is only recently that it has begun to arouse general interest. There are many
reasons for this. First, it is fascinating that simply altering the pressure and/or tem
perature can alter the dissolving power of the gas. Secondly, carbon dioxide, for
example, is available in large quantities and is cheap, non-flammable and neither
subject to crises (e.g. political) nor hostile to the environment.
Anyone wishing to learn something about the present state of knowledge of this
subject is obliged to study the patent literature (fairly extensive), the widely scattered
original publications, the few review articles (some out of date) or heterogeneous
symposium reports. There is no compilation devoted entirely to the present state of
extraction and fractionation with dense gases. We therefore decided, responding
to a request of the Springer Publishing Co., to prepare such a work. We were able
to profit from over ten years of practical experience of our research team. The main
emphasis has been laid on the possibilities of applying dense gases for obtaining and
refining naturally occurring materials. The physico-chemical principles have been
treated only in so far as they contribute to a better understanding of the high pressure
extraction. Det.c1iled considerations of phase equilibria and calculations have been
omitted; authoritative compilations of these are available. It seemed important to
us to refer in a special chapter to further, non-extractive possibilities of use of dense
gases, e.g. in combating pests or in fluid chromatography.
We have attempted to provide as full a picture as possible but are quite certain
that some things have escaped our attention. Accordingly we ask for any suggestions
which could be incorporated into a second edition. This book will have fulfilled its
purpose if it gives those interested in the use of dense gases a picture of the subject
and useful stimulation.
We thank the Friends of the University of the Saar and the "Fonds der Chemischen
Industrie" for their support; the publishers for their helpfulness; Mrs. M. C. Atherton
for typing; and colleagues of the research group for valuable discussions and sugges
tions and for providing additional material, some of which had not yet been published.
Saarbrucken, March 1986 Egon Stahl
Karl-Werner Quirin
Dieter Gerard
Contents
Symbols and Abbreviations. . . . . . . . . . . . . . . . . . . . . . . IX
I. General Picture of Separation Procedures
Ll Principles of Substance Separation 1
1.2 Conventional Methods of Extraction 3
References 7
n.
Basic Principles of Extraction with Dense Gases. 8
ILl Historical Review 8
11.2 Definition of Terms 9
11.3 Special Features of Dense Gases 11
11.4 Thermodynamic Fundamentals 13
II.4.a Description of the Solvent Circulation. 13
1I.4.b Considerations of Phase Equilibria 16
1I.4.c Calculations of Phase Equilibria 24
References 29
m. Methods, Apparatus and Plants . 32
III. 1 Procedures for Determining Phase Equilibria 32
Ill. La The Synthetic Method 32
III.I.b The Analytical Method 33
III.I.c The Dynamic Method 35
I1I.2 Extraction of Solids 37
I1I.2.a Microextraction . 37
I1I.2.b High Pressure Soxhlet Extraction. 39
I1I.2.c Preparative Extraction 40
I1I.3 Extraction Using Entrainers . 55
I1I.4 Continuous Extraction of Liquids 57
I1I.4.a Fundamentals . 57
I1I.4.b Stepwise Separation 59
I1I.4.c Counter-current Extraction 63
III.4.d High Pressure Jet Extraction ... 67
References 70
VIII Contents
IV. Applications of Dense Gases to Extraction and Refining. 72
IV.I General Survey 72
IV.2 Fatty Oils and Waxes. 81
IV.2.a Solubility Behaviour 82
IV.2.b Extraction of Oil Seeds 93
IV.2.c Extraction of Waxes 102
IV.2.d Influence on the Seed Proteins 104
IV.2.e Fractionation of Fatty Oils and Waxes 106
IV.2.f Removal of Oil from Crude Lecithin 112
IV.3 Essential Oils and Flavours 119
IV.3.a Solubility Behaviour 122
IV.3.b Deterpenation . 131
IV.3.c Extraction of Pharmaceutically Active Components. 137
IV.3.d Extraction of Spices 147
IV.3.e Extraction of Fragrances 156
IV.3.f Prior Separation of Vegetable Waxes 160
IVA Further Isoprenoids 163
IVA.a Extraction of Hops. 163
IVA.b Steroids. 168
IVA.c Carotinoids . 173
IV.5 Alkaloids. 175
IV:5.a Extraction of Alkaloids Used in l\h:dicine 175
IV.5.b Decaffeination of Coffee and Tea. 178
IV.s.c Extraction of Nicotine from Tobacco 183
IV.6 Oils of Law Volatility and Polymers 185
IV.7 Extraction of Petroleum Products 188
IV.7.a Deasphaltation of Heavy Oils 188
IV.7.b Particle Separation from Viscous Oils . 189
IV.7.c Extraction of Oil-Containing Minerals and Residues 190
IV.7.d Analytical Investigations 193
IV.8 Extraction of Wood, Peat and Lignite. 193
IV.9 Extraction of Coal . 198
IV.1O Miscellaneous . 203
IV.IO.a Extraction of Aqueous Solutions 203
IV.IO.b Adsorbents 207
IV.IO.c Decontamination of Drugs 208
References 210
V. Non-Extractive Applications 218
V.l Pest Control. 218
V.2 Sterilisation . 220
V.3 Inflation, Disruption and Comminution. 221
VA High Pressure Micronising 223
V.5 Fluid Chromatography 227
References 229
Subject Index. 233
Symbols and Abbreviations
Symbols and abbreviations used in the book are listed here. The final disposition
of all the symbols is given in the text
A aroma fraction
AV acid value
a, b parameters for intermolecular attraction and repulsion, resp.
bp boiling point
C component
CP critical point
D diffusion coefficient (cm2/s); logarithm of the reduction of bacterial
count
d density
E extract; extract flow; enhancement factor; energy
E~~;;; extinction oCa I % solution of thickness I cm
F degree of freedom
f supercritical fluid
fugacity of the component i in the reference state
f1>
g gaseous; gram
h hour
hRf measure of the migrated distance in thin-layer chromatography
IV iodine value
K partition coefficient
k number of the components of a system; capacity ratio
kw dissolving coefficient (min -1)
L lower critical end point
LCST lower critical solution temperature
I liquid
lij correction parameter for molecular interactions
M mortality percent
min minute
relative mass of solvent flow (g solvent per g sample)
refractive index
P pressure (bar)
Pc, Pr critical pressure; reduced pressure
ppb parts per billion
ppm parts per million
P phase
PV peroxide value
Q quadruple point
x
Symbols and Abbreviations
r correlation coefficient
R universal gas constant; residue; reflux
S stabiliser, solubility (mg substance per g solvent)
SM solid matter
s solid; entropy (kJjkg K)
SV saponification value
T absolute temperature (K)
Tc, Tr critical temperature; reduced temperature
TP triple point
t temperature (0C); tonne
tr time of retention
U upper critical endpoint
UCST upper critical solution temperature
V isochore; molar volume
vol volume
wt weight
x mole fraction; concentration of a component in the condensed phase
concentration of a substance in the top fraction, bottom fraction, resp.
feed fraction
mole fraction; concentration of a component in the gas phase, in the
solvent
yield
compressibility factor at the critical point
separation factor
specific rotation
dynamic viscosity
critical density
activity coefficient
fugacity coefficient
Abbreviations of Parts of the Installations
B buffer volume
BP back pressure regulator
C compressor, condenser
D safety disc, jet capillary
E extractor, equilibrium cell
ES extract separator
F filter
FC fractionation column
FM flow meter
G gas supply
H heat exchanger
I integrator
L level indicator
M manometer, mixing device
Symbols and Abbreviations XI
MP metering pump
MV metering valve
P pump
R recorder, switching relay
RC regeneration column
RH resistance heating
RS raffinate separator
RV reducing valve
S separator
SC separation column
T T-piece
V valve
VP vacuum pump
Other Abbreviations
CSD critical solvent de-ashing
DAB Deutsches Arzneibuch (= German pharmacopoeia)
DDT dichlorodiphenyltrichloroethane
DGC dense gas chromatography
DGE dense gas extraction
DSSE donor solvent supercritical extraction
DTC dithiocarbamate
ECD electron capture detector
E-TG epoxy-triglycerides
FDA Food and Drug Administration
FE-TLC fluid extraction-thin layer chromatography
FFA free fatty acids
FID flame ionisation detector
FS free sterols
GRAS generally recognised as safe
HC hydrocarbons
HCB hexachlorobenzene
HCH hexachlorocyclohexane
HPLC high pressure liquid chromatography
H-TG hydroxy-triglycerides
LSE liquid solvent extraction
MEK methyl-ethyl-ketone
MPI Max-Planck -Institute
NCB National Coal Board
NRTL non-random two liquid
NSI nitrogen solubility index
PAA polyacrylamide
PCB polychlorinated biphenyls
PE polyethylene
PMMA polymethylmethacrylate
PP polypropylene
XII Symbols and Abbreviations
PS polystyrene
PTFE polytetrafluoroethylene (teflon)
PUFA polyunsaturated fatty acids
PVC polyvinyl chloride
REM raster electron microscope
ROSE residual oil supercritical extraction
RST regular solvent theory
S sterol
SE sterol esters
SFC supercritical fluid chromatography
SOE supercritical gas extraction
TO triglyceride
TLC thin layer chromatography
UNIQUAC universal quasi-chemical theory
USDA U.S. Department of Agriculture
USP U. S. Pharmacopoeia
WAF water- and ash-free
WE wax ester
