teach yourself the basics of aspen plus

TEACH YOURSELF THE BASICS OF ASPEN PLUS ™ TEACH YOURSELF THE BASICS OF ASPEN PLUS ™ RALPH SCHEFFLAN Chemical Engineering and Materials Science Department Stevens Institute of Technology A JOHN WILEY & SONS, INC., PUBLICATION Copyright © 2011 by John Wiley & Sons, Inc. All rights reserved. A joint publication of the American Institute of Chemical Engineers and John Wiley & Sons, Inc. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. 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For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at 877-762-2974, outside the United States at 317-572-3993 or fax 317-572-4002. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at www.wiley.com. Library of Congress Cataloging-in-Publication Data: Schefflan, Ralph. Teach yourself the basics of Aspen Plus / Ralph Schefflan. p. cm. Includes bibliographical references and index. ISBN 978-0-470-56795-1 (pbk.) 1. Chemical-process–Computer simulation. 2. Chemical process control– Computer programs. 3. Aspen Plus. I. Title. TP155.7.S28 2010 660  .280113–dc22 2010019514 Printed in Singapore. oBook ISBN: 978-0-470-91006-1 ePDF ISBN: 978-0-470-91004-7 ePub ISBN: 978-0-470-92285-9 10987654321 To Ruth CONTENTS PREFACE xiii 1 INTRODUCTION TO ASPEN PLUS 1 1.1 Starting Aspen Plus / 2 1.2 Graphic Users Interface / 3 1.3 Next Button / 4 1.4 Setup Specifications Display / 5 1.5 Simulation Options / 6 1.6 Units / 6 1.7 Components / 8 1.8 Properties / 10 1.9 Streams / 12 1.10 Blocks / 14 1.11 Viewing Results / 14 1.12 Object Manager / 16 1.13 Plotting Results / 17 References / 19 2 PROPERTIES 21 2.1 Pure Component Data Banks / 21 2.2 Property Analysis / 24 2.3 Property Estimation / 25 vii viii CONTENTS 2.4 Workshops / 34 References / 35 3THESIMPLEBLOCKS 37 3.1 Mixer/Splitter Blocks / 37 3.1.1 Mixer Block / 37 3.1.2 Fsplit Block / 38 3.2 Simple Separator Blocks / 39 3.2.1 Sep Block / 40 3.2.2 Sep2 Block / 41 3.3 Some Manipulator Blocks / 42 3.3.1 Dupl Block / 42 3.3.2 Mult B lock / 44 3.4 Workshops / 45 4 PROCESSES WITH RECYCLE 49 4.1 Blocks with Recycle / 50 4.2 Heuristics / 53 4.3 Workshops / 54 References / 58 5 FLOWSHEETING AND MODEL ANALYSIS TOOLS 59 5.1 Introduction to Fortran in Aspen Plus / 59 5.2 Basic Interpreted Fortran Capabilities / 60 5.2.1 Primary Fortran Operators / 61 5.2.2 Precedence of Calculations / 61 5.2.3 Statement Format / 62 5.2.4 Program Logic Control / 62 5.3 Sensitivity Function / 63 5.4 Design Specification / 65 5.5 Calculator Function / 67 5.6 Transfer F unction / 69 5.7 Workshops / 71 References / 72 6 THE DATA REGRESSION SYSTEM 73 6.1 Parameters of Equations of State / 74 6.2 Parameters of Activity Coefficient Equations / 76 6.3 Basic Ideas of Regression / 77 6.4 Mathematics of Regression / 80 CONTENTS ix 6.4.1 Newton–Raphson Method for Solution of Nonlinear Equations / 80 6.4.2 Direct Optimization of an Objective Function / 81 6.5 Practical Aspects of Regression of VLE or LLE Data / 82 6.5.1 Regression of VLE Data / 82 6.5.2 Regression of LLE Data / 85 6.6 Workshops / 87 References / 90 7 FLASHES AND DECANTER 93 7.1 Flash2 Block / 93 7.2 Flash3 Block / 96 7.3 Decanter B lock / 99 7.4 Workshops / 101 References / 103 8 PRESSURE CHANGERS 105 8.1 Pump Block / 105 8.2 Compr Block / 105 8.3 MCompr Block / 107 8.4 Pipelines and Fittings / 107 8.5 Workshops / 109 Reference / 110 9 HEAT EXCHANGERS 111 9.1 Heater Block / 112 9.2 Heatx Block / 115 9.3 Mheatx Block / 118 9.4 Workshops / 118 References / 121 10 REACTORS 123 10.1 RStoic Block / 123 10.2 RYield Block / 125 10.3 REquil Block / 126 10.4 RGibbs Block / 128 10.5 Reactions for the Rigorous Models / 129 10.5.1 Equilibrium Class / 130 10.5.2 Powerlaw Class / 130 10.5.3 Langmuir–Hinshelwood–Hougen–Watson Class / 133 x CONTENTS 10.5.4 Generalized–Langmuir–Hinshelwood–Hougen–Watson Class / 134 10.6 RCSTR Block / 134 10.7 RPlug Block / 135 10.8 RBatch Block / 138 10.9 Workshops / 139 References / 144 11 MULTISTAGE EQUILIBRIUM SEPARATORS 145 11.1 Basic Equations / 145 11.2 The Design Problem / 148 11.3 A Three-Product Distillation Example / 150 11.4 Preliminary Design and Rating Models / 154 11.4.1 DSTWU / 154 11.4.2 Distl / 156 11.5 Rigorous Models / 157 11.5.1 RadFrac / 158 11.5.2 Extract / 164 11.6 BatchSep / 167 11.7 Workshops / 170 References / 173 12 PROCESS FLOWSHEET DEVELOPMENT 175 12.1 Heuristics / 175 12.2 Example: The Production of Styrene / 176 12.3 A Model with Basic Blocks / 177 12.4 Properties / 177 12.5 Rigorous Flash and Decanter / 178 12.6 Analyzing the Rigorous Distillation / 181 12.7 Integrating the Rigorous Distillation Into the Flowsheet / 181 12.7.1 Selection of a Tear Stream / 183 12.7.2 Sequence of Calculations / 183 12.8 Reactor Feed / 183 12.9 Miscellaneous Considerations / 185 12.10 Workshops / 185 Reference / 189 13 OPTIMIZATION 191 13.1 Optimization Example / 192 13.2 Workshops / 195 References / 198 CONTENTS xi 14 COMPLEX EQUILIBRIUM STAGE SEPARATIONS 199 14.1 Energy Integration Applications / 199 14.2 Homogeneous Azeotropic Distillation / 202 14.3 Extractive Distillation / 203 14.4 Heterogeneous Operations / 205 14.5 Workshops / 207 References / 211 INDEX 213 PREFACE During my years working as a chemical engineer in development laboratories, pro- cess engineering groups, and plant startup and support operations, the most frequently referenced documents were process flow diagrams (PFDs), which contain the material and energy balances and the basic process design information. Equally important were process and instrument diagrams (P&IDs), which contain details of all equipment, all controls, all instruments, and all lines (i.e ., process, instrument, and utilities). Process simulation software is an excellent tool for producing high-quality PFDs, and when integrated with computer-aided design software, facilitates the production of P&IDs. There are several process simulation software systems available to the chemical engi- neering community, and Aspen Plus is arguably the most popular. Teach Yourself the Basics of Aspen Plus™ evolved from two graduate courses that I taught at Stevens Institute of Technology over the past 20-odd years. The fi rst course, ChE662, is an introduction to steady-state chemical process simulation, which is usually taken by graduate students and is organized around a series of workshops that intro- duce Aspen Plus functionality. Occasionally, undergraduates are enrolled and typically experience difficulties in the thermodynamics of phase equilibrium and parameter esti- mation, due to limitations in their undergraduate courses. The second course, ChE612, deals with the analysis and design of complex equilibrium stage processes and with difficult multicolumn problems such as, extractive distillation systems. Over time, the course evolved from the use of stand-alone two- and three-phase flashes, decantation, and two-phase distillation software, to their equivalent blocks in Flowtran and later, Aspen Plus. The idea for this book originated from my observations of students in these courses. I noted that after an initial period dedicated to learning the basics of how to navigate, locate material, and enter data into Aspen Plus, students could proceed through the exercises, within the workshops, mostly on their own. I would give an introductory lecture for each subject studied, show examples, and provide individual help on the xiii [...]... No other modules are necessary 1.1 STARTING ASPEN PLUS When the Aspen Plus User Interface icon on the desktop is clicked or, alternatively, the sequence All Programs /Aspen Tech/Process Modeling V7.0 /Aspen Plus /Aspen Plus User Interface is selected from the Start menu, the Aspen Plus Startup display shown in Figure 1.1 appears A selection from a list of existing applications may also be made, or other... by selecting the Help button on the main Aspen Plus display The philosophy of the book is based on the idea that once a chemical engineer becomes thoroughly facile in the use of the software and has a good understanding of the basic blocks, he or she should be able PREFACE xv to learn to use many of the unaddressed functions by applying the same philosophy as that of the text itself: namely, to study... some of its models, which permits convenient use of design specifications in process modeling The Aspen Engineering Suite, which incorporates Aspen Plus, can be installed in a variety of ways using network servers or on a stand-alone personal computer Teach Yourself the Basics of Aspen Plus By Ralph Schefflan Copyright © 2011 John Wiley & Sons, Inc 1 2 INTRODUCTION TO ASPEN PLUS Installation is the responsibility... 1999) and in Aspen Plus s Help, and follow up with the section entitled “Generating Electrolyte Components.” I have made an effort to provide the describing equations of most of the models (blocks) referred to here, and if not possible because of the proprietary nature of the software, I have described the functionality One should recognize that Aspen Plus is proprietary software and that the source... resides on the server at Stevens Institute of Technology I recommend that while reading the text, Aspen Plus be used simultaneously to execute and review each example If Aspen Plus is not available, the txt solutions may be reviewed The book is designed to be used by undergraduates, graduate students, and practicing chemical engineers The first section of the book explains the basic structure of the software... the software and leads the student through a hands-on introduction to the various features of the software designed to facilitate the setup of simple problems Features such as the material-balance-only option, access to Aspen Plus documentation through Help, the Next button, menu navigation, and the report function are introduced The remainder of the book is organized in a series of sections that focus... Additionally, there are frequently several ways to solve the equations that describe the blocks, and there is no way to ascertain these details since Aspen Technology does not provide them I wish to acknowledge the help provided by Aspen Technology’s academic support group, especially for the loan of an Aspen Engineering stand-alone license for use while I was out of the United States and unable to access the. .. DATA BANKS All of the many data banks available in the Aspen Physical Property System can be identified by clicking the Help button at the top of Figure 2.1 The primary database is Pure22 To see the details of its content, searching Help for Pure22 will present various alternatives, one being to display the Pure22 Databank The list below, taken from Aspen Plus s documentation, describes the property categories... Temperature-dependent binary interaction parameters where the element numbers in Figure 2.3 correspond to the parameters of equation (2.1) Selection of the Results Binary Interactions with the tab T-Dependent and parameter Wilson-1 displays the binary interaction parameters of the methanol–water system as shown in Figure 2.4 The elements refer to the Aspen Plus implementation of the Wilson equation for a binary pair:... as the component water An entry is always required Alternatively, the user may enter a proper component name or component formula If neither is recognized as an entry in the database, the user may select the Find button and Aspen Plus will display a set of names or formulas that incorporate the entry For example, entering the formula C7 H8 gives the results shown in Figure 1.9 Upon selection of the . TEACH YOURSELF THE BASICS OF ASPEN PLUS ™ TEACH YOURSELF THE BASICS OF ASPEN PLUS ™ RALPH SCHEFFLAN Chemical Engineering and Materials Science Department Stevens Institute of Technology A. computer. Teach Yourself the Basics of Aspen Plus By Ralph Schefflan Copyright © 2011 John Wiley & Sons, Inc. 1 2 INTRODUCTION TO ASPEN PLUS Installation is the responsibility of either the user,. selecting the Help button on the main Aspen Plus display. The philosophy of the book is based on the idea that once a chemical engineer becomes thoroughly facile in the use of the software and