Integrated Reaction and Separation Operations: Modelling and Experimental Validation

374 Pages·2006·5.82 MB·English

by  Henner Schmidt-Traub

Chemische Technik / Verfahrenstechnik
Henner Schmidt-Traub · Andrzej Górak
Integrated Reaction and
Separation Operations
Modelling and experimental validation
With 148 Illustrations
1 3
Professor Dr.-Ing. Henner Schmidt-Traub Professor Dr.-Ing. Andrzej Górak
Universität Dortmund Universität Dortmund
FB Bio- und Chemieingenieurwesen FB Bio- und Chemieingenieurwesen
Emil-Figge-Str. 70 Emil-Figge-Str. 70
44227 Dortmund 44227 Dortmund
[email protected] [email protected]
Library of Congresss Control Number: 2006926661
ISBN 10 3-540-30148-8 Springer Berlin Heidelberg New York
ISBN 13 978-3-540-30148-6 Springer Berlin Heidelberg New York
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Preface
Economic needs as well as ecological demands are major driving forces in
improving chemical processes and plants. To meet these goals processes
have to be intensified in order to get products of higher quality, to increase
yield by reducing or even suppressing by-products and to minimise energy
consumption. A preferred principle for such intensifications is process in-
tegration, especially integration of reaction and separation operations. Sci-
entific research in this field has been boosted by certain extremely success-
ful examples like the Eastman-Kodak process for methyl acetate or the
MTBE process which are milestones for this method. In 2002 the German
Research Foundation defined process integration as one of the major re-
search topics for the next decade.
In 1998 the Department of Biochemical- and Chemical Engineering at
the University of Dortmund decided to pool its activities for concerted ef-
forts in process integration and to form a joint research cluster. Our interest
was to find out the general challenges as well as obstacles of integrated
processes and to work out methods for their design and valuation. Soon it
became clear that theoretical work only cannot give reasonable answers.
Corresponding experiments are essential to validate process modelling and
to verify process simulation. But experiments also confront research and
development with process reality as well as conditions of plant design and
operation. This necessitates an open-minded debate if theoretical assump-
tion is to suit real process behaviour and plant design. In order to cover a
broad variety of chemical processes, reactive distillation and absorption,
reactive gas adsorption, chromatographic reactors and reactive extraction
were chosen as references. But the aim to develop general design methods
cannot be met only by a collection of example processes. Own research
added by information from open literature have to be the source for gener-
alised conclusions implemented in a system for process synthesis. From
the point of view of process operation, integrated processes are getting
more and more complicated as their degree of freedom is reduced with in-
VI Preface
creasing integration. Therefore research in process control was another es-
sential.
The linkage and interrelation of our research cluster is illustrated by Fi-
gure 1.1.
TP 5 Process synthesis
TP 1 TP 2 TP 3 TP 6
Reactive Adsorptive Chromato- Reactive
Distillation Reactors graphic Extraktion
Reactors
TP 1 / TP 4 Process Control
Fig. 1.1: Research cluster: Integrated Reaction and Separation Operations
Our research cluster was sponsored by the German Research Foundation
(DFG) during two phases each of three years. The members in phase I are:
Prof. D. Agar, Reaction Engineering; Prof. S. Engell, Process Control;
Prof. A. Gorak, Thermal Separations, Dr. G. Schembecker, Process Design
Centre GmbH; Prof. H. Schmidt-Traub, Plant Design;
During phase I it became clear that the degree of freedom for process
design and operation is an important criterion for synthesis of efficient and
effective processes. This means that the distribution of the functionalities
reaction and separation within the plant may vary between homogeneous
integration and a non-integrated sequential process. Therefore the research
area was expanded to add other processes but also to investigate the degree
of process integration in more detail. The supplemented research topics in
phase II were headed by: Prof. A. Behr, Technical Chemistry; Dr. M.
Grünewald, Reaction Engineering; Prof. O. Hinrichsen, Technical Chemis-
try.
A group of PhD students formed the basis of our research as they wor-
ked in a really integrated manner. We have to thank S. Barkmann, T. Bor-
ren, C. Dittrich, M. P. Elsner, J. Fricke, S. Geisler, A. Hoffmann, E. Y.
Preface VII
Kenig, P., M. Kloeker, P. S. Lawrence, C. Noeres, S. Reßler, J. Richter,
G. Sand, J. Seuster, C. Sonntag, M. Völker, A. Toumi, M. Tylko for their
hard and ambitious work.
Special thanks also to all technicians of our laboratories. Dirk Lieftucht,
Queens University Belfast, supported us during major changes at the reac-
tive distillation plant. Special thanks go to Christian Dusny for his techni-
cal assistance.
Several companies supported our work. In particular we would like to
thank BASF AG, Bayer AG, Grace Deutschland GmbH, Degussa AG,
Protocatalyse SA, Sasol Germany GmbH, Siemens-Axiva GmbH, Süd-
Chemie AG and Umicore AG & Co. KG.
The support by Deutsche Forschungsgemeinschaft (DFG) by funding
the research cluster FOR 344 “Integration von Reaktions- and Separations-
operationen” is gratefully acknowledged.
The results and conclusions of our research are summarised in this book
where each chapter stands for a different topic of research. The overall
findings and conclusions can be summarised as follows: Process integra-
tion offers interesting challenges for process intensification. But it is not a
general recipe for successful improvements. The distribution of the func-
tionalities has to be worked out thoroughly and validated by experiments.
Process simulation is a must in order to find out optimal areas for process
operation.
Corresponding Authors VIII
Corresponding Authors
Prof. rer. nat. David Agar PD. Dr. Ing. Markus Grünewald
University of Dortmund Bayer Technology Services GmbH
Department of Biochemical and PT-RPT-REC
Chemical Engineering D-51368 Leverkusen
Chair of Chemical Reaction Engi- Germany
neering
44221 Dortmund
Germany
Prof. Dr. rer. nat. Arno Behr Prof. Dr. rer. nat. O. Hinrichsen
University of Dortmund University of Leipzig
Department of Biochemical and Department of Chemistry and Min-
Chemical Engineering eralogy
Chair of Chemical Process Devel- Institute of Technical Chemistry
opment Linnéstr. 3-4
44221 Dortmund 04103 Leipzig
Germany Germany
Prof. Dr. Ing. Sebastian Engell Prof. Dr. Ing. Gerhard Schembecker
University of Dortmund University of Dortmund
Department of Biochemical and Department of Biochemical and
Chemical Engineering Chemical Engineering
Chair of Process Control Chair of Plant and Process Design
44221 Dortmund 44221 Dortmund
Germany Germany
Prof. Dr. Ing. Andrzej Gorak Prof. Dr. Ing. Henner Schmidt-
University of Dortmund Traub
Department of Biochemical and University of Dortmund
Chemical Engineering Department of Biochemical and
Chair of Fluid Separations Chemical Engineering
44221 Dortmund Chair of Plant and Process Design
Germany 44221 Dortmund
Germany
Table of contents
1 Introduction.............................................................................................1
2 Synthesis of reactive separation processes............................................7
2.1 Introduction......................................................................................7
2.2 Fundamental process synthesis concepts..........................................8
2.3 Process synthesis strategy...............................................................17
2.3.1 Process goals...........................................................................18
2.3.2 Data acquisition / thermodynamic analysis.............................18
2.3.3 Investigation of the reaction phase..........................................19
2.3.4 Identification of incentives......................................................19
2.3.5 Selection of the separation process..........................................19
2.3.6 Knock-out criteria....................................................................21
2.3.7 Estimation of product regions for full integration...................21
2.3.8 Measures to achieve the desired product quality.....................25
2.3.9 Necessity of additional steps...................................................26
2.3.10 Simulation and optimization..................................................26
2.3.11 Examples...............................................................................27
2.4 Optimization of the process............................................................61
2.4.1 The optimization model...........................................................63
2.4.2 Solution method.......................................................................67
2.4.3 Examples.................................................................................70
2.5 Conclusions....................................................................................84
2.6 Notation..........................................................................................85
2.7 Literature........................................................................................88
3 Catalytic distillation..............................................................................95
3.1 Introduction....................................................................................95
3.2 Basics of catalytic distillation.........................................................96
3.2.1 Catalyst....................................................................................98
3.2.2 Internals.................................................................................101
3.3 Modeling.......................................................................................103
3.3.1 Equilibrium stage model........................................................105
3.3.2 Rate-based approach..............................................................106
3.4Model parameters.........................................................................110
3.4.1 Vapor-liquid equilibrium.......................................................110
3.4.2 Reaction kinetics...................................................................110
3.4.3 Hydrodynamics and mass transfer.........................................112
3.4.4 Differential models................................................................114
X Table of contents
3.5Case studies..................................................................................115
3.5.1 Methyl acetate synthesis........................................................115
3.5.2 Ethyl acetate synthesis...........................................................119
3.5.3 Ethyl acetate transesterification.............................................123
3.5.4 Dimethyl carbonate transesterification..................................127
3.6 Conclusions..................................................................................133
3.7 Notation........................................................................................135
3.8 Literature......................................................................................137
4 Reactive gas adsorption......................................................................149
4.1 Introduction..................................................................................149
4.1.1 Gas-phase adsorptive reactors – operation and regeneration
strategies................................................................................151
4.1.2 Comparison with related reactor concepts.............................153
4.2 Modeling of gas-phase adsorptive reactors..................................155
4.2.1 Model equations....................................................................155
4.2.2 Model implementation and numerical features.....................159
4.3 Design principles of adsorptive reactors.......................................160
4.4 Conversion enhancement of equilibrium-limited reactions..........161
4.4.1 Claus reaction........................................................................161
4.4.2 HCN-synthesis from CO and NH ........................................168
3
4.4.3 Water-gas shift reaction.........................................................172
4.5 Yield and selectivity enhancement for complex reaction
schemes........................................................................................172
4.5.1 Direct synthesis of DME from synthesis gas.........................173
4.5.2 Oxidative dehydrogenation of ethylbenzene to styrene.........179
4.6 Conclusions..................................................................................184
4.7 Notation........................................................................................185
4.8 Literature......................................................................................187
5 Reactive liquid chromatography.......................................................191
5.1 Introduction..................................................................................191
5.2 Process concepts...........................................................................192
5.2.1 Chromatographic batch reactor.............................................192
5.2.2 Continuous annular reactor....................................................193
5.2.3 Counter-current flow reactors................................................194
5.2.4 Degree of process integration................................................199
5.3Modeling of simulated moving bed reactors................................200
5.3.1 Rigorous models....................................................................202
5.3.2 TMBR model.........................................................................208
5.3.3 Comparison of TMBR and SMBR........................................210
5.4 Experimental model validation.....................................................211