Understanding batch chemical processes : modelling and case studies

331 Pages·2017·9.47 MB·English

by  Lee

Understanding
Batch Chemical
Processes
Modelling and Case Studies

Understanding
Batch Chemical
Processes
Modelling and Case Studies
Thokozani Majozi
Esmael R. Seid
Jui-Yuan Lee
CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2017 by Taylor & Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Printed on acid-free paper
Version Date: 20160901
International Standard Book Number-13: 978-1-4987-7317-1 (Hardback)
This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have
been made to publish reliable data and information, but the author and publisher cannot assume responsibility
for the validity of all materials or the consequences of their use. The authors and publishers have attempted to
trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if
permission to publish in this form has not been obtained. If any copyright material has not been acknowledged
please write and let us know so we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmit-
ted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented,
including photocopying, microfilming, and recording, or in any information storage or retrieval system, with-
out written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com
(http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive,
Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration
for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate
system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used
only for identification and explanation without intent to infringe.
Library of Congress Cataloging-in-Publication Data
Names: Majozi, Thokozani, author. | Seid, Esmael Reshid, author. | Lee, Jui-Yuan,
author.
Title: Understanding batch chemical processes : modelling and case studies / Thokozani
Majozi, E R Seid, and J-Y Lee.
Description: Boca Raton : Taylor & Francis, a CRC title, part of the Taylor & Francis
imprint, a member of the Taylor & Francis Group, the academic division of T&F
Informa, plc, [2017]
Identifiers: LCCN 2016034450 (print) | LCCN 2016053916 (ebook) | ISBN
9781498773171 (acid-free paper) | ISBN 9781498773188 (eBook)
Subjects: LCSH: Chemical processes.
Classification: LCC TP155.7 .M33 2017 (print) | LCC TP155.7 (ebook) | DDC
660/.2812--dc23
LC record available at https://lccn.loc.gov/2016034450
Visit the Taylor & Francis Web site at
http://www.taylorandfrancis.com
and the CRC Press Web site at
http://www.crcpress.com
Contents
Foreword ................................................................................................................xiii
Acknowledgements ..................................................................................................xv
Authors ...................................................................................................................xvii
Chapter 1 Introduction to Batch Processes ...........................................................1
1.1 Introduction ...............................................................................1
1.2 Batch Process Representation....................................................2
1.3 Different Storage Operational Policies in Batch Plant ..............4
1.4 Multipurpose and Multiproduct Batch Plants ...........................4
1.5 Scheduling Techniques for Batch Processes .............................6
1.5.1 Graphical Techniques ...................................................6
1.5.2 Mathematical Techniques .............................................8
1.5.2.1 Models Based on Precedence Sequencing....9
1.5.2.2 Models Based on Slot Representation ........10
1.6 Scheduling Techniques for Continuous and
Semi-Continuous Multistage Multiproduct Plants ..................12
1.7 Scheduling Techniques for Multipurpose Batch Plants ..........13
1.7.1 Models Based on Discrete-Time Representation .......13
1.7.2 Models Based on Global Event Point
Representations ..........................................................14
1.7.3 Models Based on Slot Time Representation ..............15
1.7.4 Models Based on Unit-Specific Event-Point
Representation ............................................................16
1.8 Conclusions ..............................................................................20
References ..........................................................................................22
Chapter 2 Modelling for Effective Solutions: Reduction of Binary Variables ...27
2.1 Introduction .............................................................................27
2.2 Necessary Background ............................................................27
2.3 Problem Statement ...................................................................29
2.4 Model Formulation ..................................................................29
2.4.1 Allocation Constraints................................................29
2.4.2 Capacity Constraints ..................................................30
2.4.3 Material Balance around a Storage Unit ....................30
2.4.4 Duration Constraints ..................................................31
2.4.5 Sequence Constraints for Processing Units................31
2.4.6 Sequence Constraints for Different Tasks in
Different Units ............................................................32
v
vi Contents
2.4.6.1 Sequence Constraints for Different
Tasks in Different Units for Stable
State That Can Wait after It Is Produced ....32
2.4.6.2 Sequence Constraints for Different
Tasks in Different Units for Unstable
States with Zero Wait .................................33
2.4.6.3 Sequence Constraint That Links the
Starting Time of the Consuming Units
with the Finishing Time of Producing
Units ............................................................33
2.4.7 Sequence Constraints for FIS Policy ..........................33
2.4.8 Time Horizon Constraints ..........................................34
2.4.9 Objective Function .....................................................34
2.5 Illustrative Example .................................................................35
2.5.1 Results and Discussion ...............................................36
2.6 Case Studies.............................................................................39
2.6.1 Case Study I ...............................................................39
2.6.1.1 Results and Discussions ..............................39
2.6.2 Case Study II ..............................................................41
2.6.2.1 Results and Discussion ...............................41
2.7 Conclusions ..............................................................................44
Nomenclature .....................................................................................44
References ..........................................................................................45
Chapter 3 Methods to Reduce Computational Time: Prediction of Time Points ....49
3.1 Introduction .............................................................................49
3.2 Motivation ................................................................................49
3.3 Problem Statement ...................................................................50
3.4 Mathematical Model Using State Sequence Network .............50
3.4.1 Allocation Constraints................................................51
3.4.2 Capacity Constraints ..................................................51
3.4.3 Material Balance for Storage......................................51
3.4.4 Duration Constraints ..................................................51
3.4.5 Sequence Constraints .................................................51
3.4.5.1 Same Task in Same Unit .............................51
3.4.5.2 Different Tasks in Same Unit .....................51
3.4.6 Different Tasks in Different Units ..............................52
3.4.6.1 If an Intermediate State Is Produced
from One Unit .............................................52
3.4.6.2 If an Intermediate State Is Produced
from More than One Unit ...........................52
3.4.7 Sequence Constraint for Fixed Intermediate
Storage Policy .............................................................52
3.4.8 Storage Constraints ....................................................52
3.4.9 Time Horizon Constraints ..........................................53
Contents vii
3.4.10 Calculation of the Total Duration a Unit Is
Active within the Time Horizon ................................53
3.4.10.1 Duration Constraints Are Fixed .................53
3.4.10.2 Duration Constraints Dependent on
Batch Size ...................................................54
3.4.11 Objective Function .....................................................54
3.4.12 Prediction of Optimal Number of Time Points ..........55
3.5 Case Studies.............................................................................57
3.5.1 Case Study I: Simple Batch Plant Involving
Three Tasks .................................................................57
3.5.1.1 Results and Discussions ..............................57
3.5.2 Case Study II: Batch Plant with a Recycle Stream ....64
3.5.2.1 Results and Discussions ..............................64
3.5.3 Case Study III: Multipurpose Batch Plant with
Six Units and Eight Tasks ..........................................67
3.5.3.1 Results and Discussions ..............................67
3.5.4 Case Study IV: Industrial Case Study ........................75
3.5.4.1 Results and Discussions ..............................78
3.6 Conclusions ..............................................................................80
Notation ..............................................................................................80
References ..........................................................................................82
Chapter 4 Integration of Scheduling and Heat Integration:
Minimization of Energy Requirements..............................................83
4.1 Introduction .............................................................................83
4.2 Necessary Background ............................................................83
4.3 Motivating Example ................................................................84
4.4 Problem Statement ...................................................................86
4.5 Model Formulation ..................................................................86
4.5.1 Mass and Energy Balances for Processing Units .......86
4.5.2 Mass and Energy Balances for Storage ......................89
4.5.3 Heating and Cooling in Processing Units ..................90
4.5.4 Heat Integration Constraints ......................................93
4.5.5 Objective Function .....................................................95
4.6 Illustrative Case Study .............................................................96
4.7 Summary ...............................................................................103
4A Appendix ...............................................................................103
Nomenclature ...................................................................................106
References ........................................................................................108
Chapter 5 Heat Integration in Multipurpose Batch Plants ................................109
5.1 Introduction ...........................................................................109
5.2 Necessary Background ..........................................................109
5.2.1 Developments in the Twentieth Century ..................110
5.2.2 Developments in the Twenty-First Century..............111
viii Contents
5.2.2.1 Models Developed for Direct Heat
Integration .................................................111
5.2.2.2 Models Developed for Indirect Heat
Integration .................................................112
5.2.2.3 Models Applied for Real Industrial
Case Studies ..............................................112
5.3 Problem Statement and Objectives ........................................114
5.4 Mathematical Formulation ....................................................114
5.4.1 Model Constraints ....................................................114
5.4.2 Model Objective Functions ......................................123
5.5 Case Studies...........................................................................124
5.5.1 Case Study I .............................................................124
5.5.1.1 Results and Discussion .............................126
5.5.2 Case Study II ............................................................130
5.5.2.1 Results and Discussion .............................131
5.5.3 Case Study III ...........................................................135
5.5.3.1 Results and Discussions ............................135
5.6 Conclusions ............................................................................141
Nomenclature ...................................................................................142
References ........................................................................................143
Chapter 6 Design and Synthesis of Heat-Integrated Batch Plants Using
an Effective Technique .....................................................................147
6.1 Introduction ...........................................................................147
6.2 Necessary Background ..........................................................147
6.2.1 Basic Grass Root Design for Multipurpose
Batch Plants ..............................................................148
6.2.2 Extended Design ......................................................149
6.3 Problem Statement .................................................................150
6.4 Model Formulation ................................................................151
6.4.1 Equipment Existence Constraints ............................151
6.4.2 Unit Size Constraints ................................................151
6.4.3 Capacity Constraints ................................................151
6.4.4 Material Balance for Storage....................................152
6.4.5 Material Balance around the Processing Unit..........152
6.4.6 Existence Constraints for Piping ..............................153
6.4.7 Duration Constraints (Batch Time as a Function
of Batch Size) ...........................................................153
6.4.8 Sequence Constraints ...............................................153
6.4.8.1 Same Task in Same Unit ...........................154
6.4.8.2 Different Tasks in Same Unit ...................154
6.4.9 Sequence Constraints for Different Tasks in
Different Units ..........................................................154
6.4.9.1 If an Intermediate State s Is Produced
from One Unit ...........................................154
Contents ix
6.4.9.2 If an Intermediate State Is Produced
from More than One Unit .........................155
6.4.9.3 Sequence Constraints for Completion
of Previous Tasks ......................................155
6.4.10 Sequence Constraints for Finite Intermediate
Storage (FIS) Policy .................................................155
6.4.11 Time Horizon Constraints ........................................156
6.4.12 Energy Integration Constraints ................................156
6.4.13 Objective Function ...................................................158
6.5 Case Study .............................................................................159
6.6 Results and Discussion ..........................................................159
6.7 Conclusions ............................................................................163
Nomenclature ...................................................................................163
References ........................................................................................166
Chapter 7 Simultaneous Scheduling and Water Optimization:
Reduction of Effluent in Batch Facilities .........................................169
7.1 Introduction ...........................................................................169
7.2 Motivation for the Study ........................................................169
7.3 Problem Statement .................................................................171
7.4 Problem Superstructure .........................................................171
7.5 Mathematical Formulation ....................................................172
7.5.1 Sets ...........................................................................172
7.5.2 Variables ...................................................................173
7.5.3 Parameters ................................................................174
7.5.4 Mass Balance Constraints ........................................174
7.5.4.1 Mass Balance around a Unit j ...................174
7.5.4.2 Mass Balance around Central Storage ......176
7.5.4.3 Mass Balance around the Regenerator .....177
7.5.5 Scheduling Constraints ............................................178
7.5.5.1 Task Scheduling ........................................178
7.5.5.2 Recycle/Reuse Scheduling ........................179
7.5.5.3 Central Storage Scheduling ......................180
7.5.5.4 Regenerator Scheduling ............................182
7.5.6 Feasibility and Time Horizon Constraints ...............183
7.5.7 Objective Function ...................................................184
7.6 Case Studies...........................................................................185
7.6.1 Cast Study I ..............................................................185
7.6.1.1 Results and Discussion .............................186
7.6.2 Case Study II ............................................................188
7.6.2.1 Results and Discussion .............................190
7.7 Conclusions ............................................................................191
7A Appendix ...............................................................................191
References ........................................................................................195