Hydrodynamics of Gas-Liquid Reactors E-Book

Barry Azzopardi

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

Seitenzahl: 505

Veröffentlichungsjahr: 2011

Beschreibung

The design of chemical reactors and their safety are as critical to the success of a chemical process as the actual chemistry taking place within the reactor. This book provides a comprehensive overview of the practical aspects of multiphase reactor design and operation with an emphasis on safety and clean technology. It considers not only standard operation conditions, but also the problems of runaway reaction conditions and protection against ensuing over-pressure.

Hydrodynamics of Multiphase Reactors addresses both practical and theoretical aspects of this topic. Initial chapters discuss various different types of gas/liquid reactors from a practical viewpoint, and later chapters focus on the modelling of multiphase systems and computational methods for reactor design and problem solving. The material is written by experts in their specific fields and will include chapters on the following topics: Multiphase flow, Bubble columns, Sparged stirred vessels, Macroscale modelling, Microscale modelling, Runaway conditions, Behaviour of vessel contents, Choked flow, Measurement techniques.

Leseprobe

Contents

Cover

Title Page

Copyright

List of Figures

List of Tables

Preface

Nomenclature

Chapter 1: Introduction

Part One

Chapter 2: Bubble Columns

2.1 Introduction

2.2 Types of Bubble Columns

2.3 Introduction of Gas

2.4 Disengagement of Liquid from Gas

References

Chapter 3: Sparged Stirred Vessels

3.1 Introduction

3.2 Flow Regimes

3.3 Variations

3.4 Spargers

3.5 Impellers

3.6 Baffles

3.7 Power Requirements

3.8 Gas Fraction

3.9 Mass Transfer

3.10 Mixing Times

References

Chapter 4: Thin Film Reactors

4.1 Introduction

4.2 Falling Film Reactors

4.3 Rotating Disc Reactors

4.4 Two-Phase Tubular Reactors

4.5 Monolith Reactors

References

Chapter 5: Macroscale Modelling

5.1 Introduction

5.2 Eulerian Multiphase Flow Model

5.3 Poly-Dispersed Flows

5.4 Gassed Stirred Vessels

5.5 Summary

References

Chapter 6: Mesoscale Modelling Using the Lattice Boltzmann Method

6.1 Introduction

6.2 Lattice Boltzmann Method and the Advantages

6.3 Numerical Simulation of Single-Phase Flow and Heat Transfer

6.4 Numerical Simulation of Two-Phase Flow

References

Part Two

Chapter 7: Upset Conditions

7.1 Introduction

7.2 Active Relief Methods

7.3 Passive Relief Methods

References

Chapter 8: Behaviour of Vessel Contents and Outflow Calculations

8.1 Introduction

8.2 Modelling of the Level Swell Process

8.3 Vent Sizing and Vent Performance Calculations

8.4 Computer Codes for Level Swell and Venting Calculations

8.5 Obtaining Necessary Data

8.6 Performance of Models and Codes

References

Chapter 9: Choked Flow

9.1 Introduction

9.2 Single-Phase Flow

9.3 Two-Phase Flow

9.4 Effect of Vent Pipework

References

Part Three

Chapter 10: Measurement Techniques

10.1 Bubble Columns

10.2 Sparged Stirred Tanks

10.3 Falling Film Reactors

References

Color Plates

Index

This edition first published 2011.

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Library of Congress Cataloging-in-Publication Data

Hydrodynamics of gas-liquid reactors : normal operation and upset conditions / B.J. Azzopardi . . . [et al.].

p. cm.

Includes bibliographical references and index.

ISBN 978-0-470-74771-1

1. Chemical reactors–Design and construction. 2. Chemical reactors–Fluid dynamics–Mathematical models. 3. Gas-liquid interfaces. I. Azzopardi, B.J. (Barry J.)

TP157.H93 2011

660'.2832–dc22

2011004546

A catalogue record for this book is available from the British Library.

Print ISBN: 9780470747711

ePDF ISBN: 9781119970323

oBook ISBN: 9781119970712

ePub ISBN: 9781119971405

Mobi ISBN: 9781119971412

List of Tables

Table 2.1Dependence of exponent of Richardson and Zaki [31] on Reynolds number

Table 2.Q.1Properties of the fluids employed at process conditions

Table 4.1Constants [1] for Equation 4.28

Table 5.1Drag coefficients for a single rising bubble in water by Wang [4]

Table 5.2Case definition and parameters used

Table 7.1Causes of runaways

Table 8.1Examples of experiments involving chemical reactions employed in runaway/venting studies

Table 8.2Properties of the reactants and reaction product for the esterification of acetic anhydride by methanol or its hydrolysis by water

Table 8.3Effect of fill level and presence of surfactant on major parameters during the runaway hydrolysis of acetic anhydride in a 2500 l vessel

Table 8.4Characteristics of codes used in level swell/venting calculations

Table 8.Q.1Contents of reactor after all chemicals added

Table 8.Q.2Data for Question 4

Table 10.1Comparison of gas fraction

Table 10.Q.1Solutions to Question 10.1

Preface

One way of identifying areas of importance in Chemical Engineering is to look at the subject groups or working parties of national or transnational professional bodies. Amongst the Working Parties of the European Federation of Chemical Engineers, there are two that are relevant to the present text, one on Chemical Reaction Engineering and the other on Multiphase Flow. Although each has its own programme of events, they come together once in a while to air matters of common interest. Multiphase flow, the simultaneous flow of more than one phase, has applications in: electrical power generation – nuclear and fossil fired; oil and natural gas production and refining; distillation and absorption and in heat transfer. This has produced a body of knowledge that can be drawn on for the benefit of the design of chemical reactors.

The relative efforts in the two facets of reactor design have been very succinctly illustrated in Figure A A, by Professor Octave Levenspiel [Levenspiel, O. (1999) Chemical Reaction Engineering, Ind. Eng. Chem. Res. 38, 4140–4143]. This text aims at strengthening the weaker link of the chain shown.

Figure A Reprinted with permission from Industrial & Engineering Chemistry Research, 38, 11, Chemical Reaction Engineering, Levenspiel © 1999, Americal Chemical Society

The preparation of this present work brought together a team with complimentary skills. All are firmly based in multiphase flows and they research into chemical reactor applications in addition to other industrial applications. The work presented here is an expression of the realization that there is the need for more and more complex modeling methods. There are also requirements to consider not just mixing but also separation of gas and liquid and to look into the upset conditions, which might lead to accidents, as well as a steady state. All of these have found a place in this book from the point of view of multiphase flows, in a combination of well proven engineering concepts and modern developments, both numerically and experimentally.

Nomenclature

Aconstant in Equation 2.45 [–]Aconstant in film thickness correlating equation [–]Aconstant in mass transfer equation (Chapter 4) [–]Across-sectional area of vessel (Chapter 8) [m2]Aconstant in Antoine equation (Chapter 8) [–]ADdrag force coefficient [–]AHHamaker constant [–]Approjected area of one wire [m2]atransverse dimension of elliptical bubble [m]aconstant in Equation 2.45 [–]aparameter in upper limit log normal equation [–]aconstant in Equation 5.14a′specific interfacial area (also known as interfacial area density) [1/m]Bconstant in film thickness correlating equation [–]Bconstant in mass transfer equation (Chapter 4) [–]Bratio of latent heat to gas constant in Antoine equation (Chapter 8)baxial dimension of elliptical bubble [m]bconstant in Equation 2.45 [–]bconstant in Equation 5.14Cconstant of integration in falling film analysis [kg/m s]Cconstant in mass transfer equation (Chapter 4) [–]C′constant of integration in falling film analysis [m/s]