Design of Multiphase Reactors E-Book

Vishwas G. Pangarkar

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1063

Veröffentlichungsjahr: 2014

Beschreibung

Details simple design methods for multiphase reactors in the chemical process industries * Includes basic aspects of transport in multiphase reactors and the importance of relatively reliable and simple procedures for predicting mass transfer parameters * Details of design and scale up aspects of several important types of multiphase reactors * Examples illustrated through design methodologies presenting different reactors for reactions that are industrially important * Includes simple spreadsheet packages rather than complex algorithms / programs or computational aid

Leseprobe

DESIGN OF MULTIPHASE REACTORS

VISHWAS GOVIND PANGARKAR

Formerly Professor of ChemicalEngineering and Head of Chemical Engineering DepartmentInstitute of Chemical TechnologyMumbai, India

Copyright © 2015 by John Wiley & Sons, Inc. All rights reserved

Published by John Wiley & Sons, Inc., Hoboken, New JerseyPublished simultaneously in Canada

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Library of Congress Cataloging-in-Publication Data:

Pangarkar, Vishwas G. Design of multiphase reactors / Vishwas G. Pangarkar.  pages cm Includes bibliographical references and index.

 ISBN 978-1-118-80756-9 (hardback)1. Chemical reactors. I. Title. TP157.P256 2014 660′.2832–dc23    2014020554

Cover image courtesy of Vishwas Govind Pangarkar

Prajá-pataye Swaáhá. Prajá-pataye Idam Na Mama.

This ancient Sanskrit Mantra can be explained as follows:“I offer the spiritual and material resources used to producethis work to Prajapaty (the Cosmic creator of Life).Oh Creator, this is not mine, but Thine.”

Foreword

Multiphase reactors are widely used in the chemical industry. The design and scale-up of such reactors is always a difficult task and is not adequately covered in traditional chemical reaction engineering books. The book by Pangarkar is a welcome addition to this field and brings a new perspective of combining the theory with practice.

The book opens with examples of industrial applications and addresses many issues associated with the success of industrial multiphase processes, such as catalyst selection, selectivity, environmental issues. It proceeds then to address the key problem of design and scale-up. The transport–kinetic interaction is vital to understand the design of these reactors. The author illustrates this clearly for various cases of both gas–liquid and gas–liquid–solid systems. Next, reactor selection is discussed in detail including the need for efficient heat management culminating with guidelines for selection of reactors. This is vital in industrial practice as a wrong type of reactor can lead to inefficient or poor process. Fluid dynamic aspects and scale-up based on similarity principles are examined next. Stirred tank reactor design is then examined through detailed analyses of both conventional multiphase chemical reactions and cell culture technology. A second case study deals with venturi loop reactor that is widely used for high-pressure hydrogenations in the fine chemicals sector. The last case study deals with sparged reactors that are of great relevance in gas to liquid fuels in the current context. These case studies are provided in a clear manner with appropriate worked examples and show how the theory can be applied to practice. Overall the book will be valuable for industrial practitioners and will help them to design these reactors in a fundamentally oriented way.

From a teaching point of view, many schools do not offer advanced courses in multiphase reactor design. Further, existing courses also do not cover it adequately. Lack of appropriate textbook may be one reason why this material that is so vital to industrial practice is not effectively covered. By including a number of appropriate case studies, Pangarkar has remedied this and fulfilled an important gap in the current teaching of Chemical Reactor Design. This book could therefore be used for special topic course or in a second course in Chemical Reaction Engineering. I presume that such a course is currently taught in Institute of Chemical technology, Mumbai, formerly known as UDCT. Both Pangarkar and I were fortunate to do our doctoral work in this field in this prestigious school and I have contributed to this field with my earlier coauthored book (with R. V. Chaudhari) Three Phase Catalytic Reactor, which has been quite popular with industrial practitioners and academicians. I believe that this book by Pangarkar will be equally popular and I endorse and recommend it to my colleagues in academia and industry.

P. A. RAMACHANDRAN

Professor, Department of Energy, Environmental and Chemical Engineering,Washington University in St. Louis, MO, USA

Preface

A practicing chemical engineer invariably comes across one or the other type of a multiphase reactor. The preponderance of multiphase reactors in the chemical process industry has given rise to widespread research directed toward understanding their behavior particularly with a view to develop reliable design and scale-up procedures. The literature is replete with information on various types of multiphase reactors. Additional information is being regularly generated on various aspects of multiphase reactors. The efforts in this direction are using increasingly sophisticated tools like Laser Doppler Anemometry/Velocimetry, computational fluid dynamics, etc. It will be long before the last word is written on design of multiphase reactors. Although this fresh information is welcome, the time and money required for it is disproportionately high, and hence there is a need for simpler, yet theoretically sound, methods to be applied.

Engineering is the bridge that spans the distance between Art and Science. Engineering can convert a seemingly intractable problem into a technically approachable one. Danckwerts (1961) pointed out that the tendency to go more scientific calls for some caution and that “we ought to produce more powerful teaching methods for developing both insight and the qualitative analysis of the problem.” The fine balance between Science and Engineering in any text must be maintained since as another doyen of chemical engineering, Thomas Sherwood (1961) noted “if perspective is lost through enthusiasm for scientific and mathematical analyses, an engineer will be less effective in industry.” The profound statements of these all-time great chemical engineers are extremely relevant to the present state-of-the art methods for design of multiphase reactors. Astarita (1997) while agreeing with Danckwerts and Sherwood argued that the enthusiasm for computational analyses must be separated from simple creative arguments. This book is an attempt to practice what Albert Einstein suggested Everything should be made as simple as possible, but not simpler.

A number of excellent texts dealing with design of multiphase reactors have been published (Shah 1979; Ramachandran and Chaudhari 1983; Doraiswamy and Sharma 1984; Trambouze et al. 1988; Westerterp et al. 1988; Harriott 2003). This book attempts to provide process design procedures for a variety of industrially important multiphase reactors. The basis of the procedures developed is that whereas the intrinsic kinetics of any multiphase reaction do not vary with the type of the reactor used and its scale, the transport parameters (in particular the gas–liquid/solid–liquid mass transfer coefficients) depend on both the type of reactor and its size. The intrinsic kinetics can be determined on small scale under appropriate conditions, but the transport properties need to be specific to the type and size of the reactor. This book therefore focuses on the development of credible correlations for predicting the mass transfer coefficients. It relies extensively on the findings of my research group at the University Department of Chemical Technology (UDCT), Mumbai, in developing these simple procedures. The tradition of industrial consulting at UDCT, an institute established by the very desire of the chemical industry, enabled me to understand the industrial world and its problems. Industrial consulting is a rich source of valuable research tips. It leads to quality research of industrial relevance combined with academic punch. This consulting experience over the last 40 years starting with Late Mr. Chandrakant Khagram (Evergreen Pvt. Ltd., Mumbai) provided me with a perspective that no classroom learning could have substituted. The concepts of “turbulence similarity,” “relative suspension,” and “relative dispersion” used in Chapters 6, 7A, and 7B have their roots in this industrial interaction. Theory without practice is generally considered “dry.” However, experience convinced me that practice without theory can be disastrous.

This book should be of special interest to process design engineers in the chemical, fine chemicals, and allied industries. Chapter 7A uses the concepts of relative suspension/dispersion mentioned earlier for a simple spreadsheet-based design procedure for the highly complex stirred reactor. Chapter 8 is the first comprehensive chemical engineering–based treatment of the venturi loop reactor. This reactor has no serious competition in the fine chemicals industry. Unfortunately, most of the information pertaining to it is proprietary. The spreadsheet-based design provided in Chapter 8 should be of special interest to the fine chemicals sector. Chapter 7B is also probably a similar, first of its type treatment of stirred reactors for cell culture technology, a frontier area in healthcare. As explained in Chapter 3, specific reactor types are best suited to specific applications in the chemical industry. The treatment of various reactors has been arranged into chapters, more or less, in a self-contained manner. There is, however, some inevitable repetition among chapters, which I hope, would only serve to reinforce understanding in the respective context. The commonality in terms of basic design features has, however, not been ignored as evinced, for instance, in Chapters 7A and 7B.

The chemical and allied industry is continuously evolving. Newer molecules/processes are being developed. In most cases, the time span between discovery and commercial exploitation tends to be very short. Therefore, the process designer has to either quickly do a reliable design of a suitable multiphase reactor or use an available one. Either way, the simplified spreadsheet-based design procedures for the stirred and venturi loop reactor should find favor with the process design engineering fraternity.

The author is grateful to his students: Aditi Deshpande, Bhushan Toley, Biswa Das, Dhananjay Bhatkhande, Keshavan Niranjan, Manoj Kandakure, Niteen Deshmukh, Prasad Pangarkar, Prashant Mandare, Rajendra Prasad, Randheer Yadav, Sameer Bhongade, Sanjay Kamble, Satish Bhutada, Sri Sivakumar, Venkatesh Shirure, Yogesh Borole and colleague Professor Sudhir Sawant for help in literature details, checking of the spreadsheets and overall comments on the flow of information and readability of the book. Professor Sawant’s support on a personal level at crucial stages is also gratefully acknowledged. Special thanks are due to Vishwanath Dalvi and Arun Upadhyaya for regressions of published data. The author gratefully acknowledges help from Mr. Manoj Modi (Reliance Industries Ltd., Mumbai, India) during the initial stages of the project on venturi loop reactor. The diligence of Rahul Bagul and timely corrections by Ajay Urgunde in the artwork is highly appreciated.

Finally, my family, who walked the path and endured my long working hours over the past 7 years, deserve all thanks.

The author sincerely hopes that the information given in this text will make the life of the process design engineer easier. The reductionist approach adopted should appeal to students who wish to unravel the complexities of chemical process equipments through simple arguments.

The workbook files are available at the Wiley Book Support site (http://booksupport.wiley.com).

VISHWAS GOVIND PANGARKAR

Nashik, India

References

Astarita G. (1997) Dimensional analyses, scaling and orders of magnitude. Chem. Eng. Sci., 52:4681–4698.

Danckwerts PV. (1961) Review of BSL. Endeavour, XX(801):232–235.

Doraiswamy LK, Sharma MM. (1984) Heterogeneous reactions: analysis, examples, and reactor design, Vol. 2: Fluid-fluid-solid reactions, John Wiley Interscience, New York, USA.

Harriott P. (2003) Chemical reactor design. Marcell-Dekker, New York, USA.

Ramachandran PA, Chaudhari RV. (1983) Three phase catalytic reactors. Gordon & Breach Science Publishers Inc., New York, USA.

Shah YT. (1979) Gas-liquid-solid reactor design, McGraw-Hill International Book Company, New York, USA.

Sherwood TK. (1961) Review of BSL. Chem. Eng. Sci., 15(9):332–333.

Trambouze P, Euzen J-P. (2004) Chemical reactor design and operation. Editions Technip, Paris, France.

Westerterp KR, van Swaaij WPM, Beenackers AACM

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(1988) Chemical reactor design and operation. 2nd ed. John Wiley & Sons Inc., New York, USA.