© 1999 by CRC Press LLC Fluid Bed Technology in Materials Processing © 1999 by CRC Press LLC Library of Congress Cataloging-in-Publication Data Catalog information may be obtained from the Library of Congress This book contains information obtained from authentic and highly regarded sources. Reprinted material is quoted with permission, and sources are indicated. A wide variety of references are listed. Reasonable efforts have been made to publish reliable data and information, but the author and the publisher cannot assume responsibility for the validity of all materials or for the consequences of their use. Neither this book nor any part may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, microfilming, and recording, or by any information storage or retrieval system, without prior permission in writing from the publisher. The consent of CRC Press LLC, does not extend to copying for general distribution, for promotion, for creating new works, or for resale. Specific permission must be obtained in writing from CRC Press LLC for such copying. Direct all inquiries to CRC Press LLC, 2000 Corporate Blvd., N.W., Boca Raton, Florida 33431. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation, without intent to infringe. © 1999 by CRC Press LLC. No claim to original U.S. Government works International Standard Book Number 0-8493-4832-3 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Printed on acid-free paper © 1999 by CRC Press LLC Foreword Fluidization engineering, which owes its origin and credibility to chemical engi- neering, has now emerged as a separate branch of engineering with a multitude of applications ranging from conventional to advanced engineering. A good deal of progress in terms of research and development has been made in this area over the past two decades, and this elegant unit operation is now being adopted for efficiency enhancement in process and energy industries. The approach of Dr. C.K. Gupta and Dr. D. Sathiyamoorthy of the Bhabha Atomic Research Centre is to painstakingly bring together the wealth of information in this field and to present it concisely in a book on fluid bed technology in materials processing. The aim and scope of this volume as indicated by the title are well achieved. It is not out of context to note that Dr. Gupta and his colleagues have contributed phenomenally to our materials program. The quality of authorship of Dr. Gupta in particular and of his partners as co-authors on the whole is well reflected in his seven books published to date. Dr. Gupta and his colleagues have been instrumental in the development of several exotic materials and in initiating the materials devel - opment program for the Department of Atomic Energy. I might add here that this kind of research is the first of its kind in India and compares well with that in some of the world-class laboratories with similar objec - tives. I understand that some excellent experimental work is being carried out, such as work related to distributor design, electrothermal fluid bed chlorination, radioac - tive waste incineration, and three-phase fluidization. Thus, Dr. Gupta and Dr. Sathiyamoorthy, with all their knowledge and expertise in the theory and practice of fluidization, are very well equipped to competently handle the objectives set forth for the present volume. The book is divided into six chapters, beginning with the basics of fluidization and then giving an account of its value and use in applied areas in the chapters that follow. The topic of each chapter has been chosen well, and the text is amply supplemented by numerous illustrations and carefully selected references. It is not an exaggeration to comment that this book is replete with valuable information which has hitherto been scattered throughout literature. The book certainly will serve as an important reference source for research scientists in materials processing, prac - ticing process engineers, graduate students, and for fluidization engineers who would like to retrieve good information on this exclusive topic. I am sure this volume will be as useful as the other books which Dr. C.K. Gupta has authored himself and co- authored with his colleagues. I congratulate the authors and wish them success. Anil Kakodkar Director, Bhabha Atomic Research Centre Member, Atomic Energy Commission, India © 1999 by CRC Press LLC Preface The voluminous body of scientific and technical literature published to date on fluidization bears ample testimony to the enormous interest in this field. The chem - ical engineering discipline has experienced phenomenal gains from the use of this process. This powerful technique has also started making significant inroads in other disciplines, and in this context special mention must be made of the field of materials processing. It has already been established as a peer technique in some processes and has enormous application potential in a number of existing and emerging processes. However, no book on fluidization as applied to materials processing was published until now. It is superfluous to point out the need for a book devoted to this illustriously important field. For quite some time, we in the Materials Group of the Bhabha Atomic Research Centre have been involved in research and development pertaining to the application of fluidization to materials processing problems. Examples include an assortment of processes such as sulfation roasting, chlorination, fluorination, incineration of radioactive waste, and reduction of metals from their oxidic origins. This involve - ment, supplemented by our extensive studies on and appreciation of fluidization, led us to undertake the present book. The presentation is organized into six chapters. Chapter 1 deals with the basics of fluidization. It starts with an introduction to fluid particle systems in general, followed by a description of the relevant fundamental parameters. Various types of fluidization, such as gas–solid, liquid–solid, and three-phase fluidization, are dis - cussed. The general aspects of heat and mass transfer and the end zones of fluidized beds are also dealt with. This opening chapter, in essence, sets the stage for the subsequent chapters. Chapter 2 is devoted to the applications of fluidization in the extraction and processing of minerals, metals, and materials. The applications of fluidization in drying, roasting, calcination, direct reduction, halogenation, and selective chlorina - tion figure in the presentation. Chapter 3 describes the importance of fluidization in the nuclear fuel cycle. Areas such as leaching, uranium extraction, and nuclear fuel preparation are covered with reference to selection and application of the fluidization technique. The signif - icant role played by fluidization in the nuclear fuel cycle as a whole and in the processing of nuclear materials in particular is brought out. Chapter 4 deals with the novel concepts of plasma fluid beds and electrothermal fluidized beds. These fluid bed reactors are described, along with their characteristic behaviors and their applications in high-temperature process metallurgy. Chapter 5 covers the design aspects of fluidized bed reactors. The prediction and judicious selection of various critical parameters such as operating velocity, aspect ratio, and pressure drop are discussed, and features such as the distributor and its design principles are presented. Modeling aspects of gas fluidized beds and a comparison of the performance of various models are also included in this chapter. Chapter 6 covers the latest developments in and applications of fluidization in the modern engineering world. Various new techniques of fluidization, such as © 1999 by CRC Press LLC magnetically stabilized fluidized beds and compartmented fluidized beds, are described. Semifluidized beds are among the other novel topics presented. The essential features of the fluidized electrode cell and its potential uses in the electro - extraction of metals are highlighted in this chapter. The advent of fluidized beds in bioprocessing and the multitude of bed configurations used to carry out bioreactions are covered separately in the closing part of the chapter. This volume should prove useful to faculties in metallurgy as well as chemical engineering. It can also serve as a reference for professionals who deal with high- temperature materials and nuclear chemical engineering and as a handy source for all interested in this subject. We believe that this book in its own right will invariably find its way into various educational institutions and research centers interested in metallurgy and materials technology. Lastly, we hope you will enjoy reading this book as much as we enjoyed writing it. C.K. Gupta D. Sathiyamoorthy © 1999 by CRC Press LLC Dedication No writer dwells in a vacuum; no author’s work is untouched, in one way or another, by associates, friends, and family. The following warm-hearted people gave so much of themselves — personally and/or professionally — and this book is far better than it could possibly have been without them. P.L. Vijay, V. Ramani, V.H. Bafna, M.G. Rajadhyaksha, S.M. Shetty, K.P. Kadam, and P.S. Narvekar were especially instrumental, directly or indirectly, in the writing of this book. The select team of Poonam Khattar, Rajashree Birje, and Yatin Thakur cheerfully and caringly transformed the handwritten material into the typed version and pre - pared neat and clear drawings and illustrations. Marsha Baker and Felicia Shapiro, our contacts at the editorial and manuscript- processing levels at CRC Press LLC, helpfully, patiently, and perceptively guided us toward completion of the task we undertook. They were understanding in liberally granting us numerous extensions for submission of the manuscript and in accom - modating us in the publication schedule. P. Mukhopadhyay gave some of his precious time to critically go through the manuscript and offer constructive suggestions. We owe a great deal to all of them. Chandrima Gupta, Chiradeep Gupta, the late P.C. Gupta, S. Sasikala, S. Shiva Kumar, S. Srinivas, and the late D. Pappa, our family members, sustained us by their interest and support and by their acceptance, with characteristic cheerfulness, of the sacrifices involved. We are greatly indebted to all of them. As a token of what we owe to the inspiration provided by this group of people and to express our deepest gratitude and thanks, this work is dedicated to them with due respect, regard, love, affection, and fond reminiscences. © 1999 by CRC Press LLC Acknowledgments The authors gratefully acknowledge the following sources that kindly granted permission to use some of the figures and tables that appear in the book: Elsevier Sequoia, S.A., Lausanne, Switzerland; American Institute of Chemical Engineers, New York; Elsevier Scientific Publishing Company, Amsterdam, The Netherlands; Hemisphere Publishing Corporation, Washington, D.C.; Elsevier Science, Ltd., The Boulevard, Langford Lane, Kidlington, Oxford, U.K.; Canadian Society for Chem - ical Engineering, The Chemical Institute of Canada, Ottawa; Academic Press, New York; Gordon and Breach Publishers, Langhorne, Pennsylvania; The Metallurgical Society of the AIME, Warrendale, Pennsylvania; John Wiley & Sons, New York; Wiley Eastern Ltd., New Delhi, India; Ann Arbor Science Publishers, Ann Arbor, Michigan; Pergamon Press Ltd., Oxford, U.K.; Pergamon Press Inc., New York; International Union of Pure and Applied Chemistry, Eindhoven, The Netherlands; Butterworths, Australia; American Ceramic Society, Westerville, Ohio; Heywood & Co. Ltd., London; Materials Research Society, Pittsburgh, Pennsylvania; Elsevier Science, Amsterdam, The Netherlands; Gordon and Breach Science Publishers, The Netherlands; and the Institution of Chemical Engineers, England. © 1999 by CRC Press LLC The Authors C.K. Gupta, Ph.D., is Director of the Materials Group at the Bhabha Atomic Research Centre (BARC), Mumbai, India. He received his B.Sc. and Ph.D. degrees in Metallurgical Engineering from Banaras Hindu University, Varanasi, India. He is a research guide for M.Sc. (Tech.) and Ph.D. students at Bombay University, Mumbai. Dr. Gupta specializes in the field of chemical metallurgy. He is responsible for research, development, and production programs on a wide range of special metals and materials of direct relevance to the Indian nuclear energy program. He is the recipient of a number of awards for the contributions he has made to metallurgical science, engineering, and technology, including setting up production plants. Dr. Gupta is associated with many professional societies. He is on the editorial board of a number of national and international journals and is a prolific contributor to the metallurgical literature. In addition to seven books, with two more in the pipeline, from publishers such as CRC Press LLC, Elsevier, and Gordon and Breach, he has authored 190 publications, which include research papers, reviews, and popular scientific articles. He has also served as guest editor for a number of special publications. D. Sathiyamoorthy, Ph.D., is currently Head, Process Engineering Section of the Materials Processing Division of the Materials Group at the Bhabha Atomic Research Centre (BARC), Mumbai, India. He joined the center in 1975. Dr. Sathiyamoorthy graduated in Chemical Engineering in 1974 from A.C. College, University of Chennai, Chennai, India. He obtained his Ph.D. in Chemical Engineering in 1984 from the Indian Institute of Technology, Mumbai. During 1989–90 he was a research fellow at the University of Queensland, Australia, and during 1990–91 was an Alexander Von Humboldt Research Fellow at Technical University, Clausthal, Germany. He is an invited JSPS fellow (1997–98) in the Department of Chemical Engineering at Tokyo University of Agriculture and Tech - nology under the Japan Society for the Promotion of Sciences. His professional involvement is with process engineering, operation, and opti- mization in mineral/extractive metallurgy. His current research is focused on fluid- ization engineering as applied to process and extraction metallurgy. He has authored and co-authored over 60 technical papers. © 1999 by CRC Press LLC Table of Contents Foreword Preface Dedication Acknowledgments The Authors Chapter 1 Generalities and Basics of Fluidization I. Introduction A. Fluidlike Behavior B. Fluidization State 1. Gas/Liquid Flow 2. Onset of Fluidization 3. Situation at the Onset of Fluidization 4. Bed Pressure Drop C. Advantages of Fluidized Bed D. Disadvantages of Fluidized Bed II. Properties of Particles and the Granular Bed A. Particles 1. Size 2. Definition 3. Sphericity 4. Roughness B. Granular Bed 1. Bed Porosity or Voidage 2. Voidage and Packing 3. Polydisperse System 4. Container Effect 5. Important Properties of Particulate Solids a. Density b. Angular Properties III. Grouping of Gas Fluidization A. Hydrodynamics-Based Groups 1. Geldart Groups 2. Molerus Groups 3. Clark et al. Groups 4. Dimensionless Geldart Groups B. Hydrodynamics- and Thermal-Properties-Based Groups C. Variables Affecting Fluidization D. Varieties of Fluidization IV. Hydrodynamics of Two-Phase Fluidization A. Minimum Fluidization Velocity 1. Experimental Determination © 1999 by CRC Press LLC a. Pressure Drop Method b. Voidage Method c. Heat Transfer Method 2. Theoretical Predictions a. Dimensional Analysis (Direct Correlation) b. Drag Force Method c. Pressure Drop Method d. Terminal Velocity Method B. Terminal Velocity 1. Definition 2. Mathematical Representation 3. Drag Coefficient a. Evaluation of Drag Coefficient b. Correlations for Drag Coefficient 4. Terminal Velocity for Single Spherical Particle 5. Difficulties in Predicting Particle Terminal Velocity 6. Some Advances in Predicting Particle Terminal Velocity 7. Experimental Methods for Determining Particle Terminal Velocity a. Common Procedures b. Relative Methods V. Flow Phenomena A. Particulate and Aggregative Fluidization B. Regimes of Fluidization 1. Bubbling Bed 2. Turbulent Bed 3. Fast Fluidization 4. Dilute-Phase Flow 5. Flow Regime Mapping VI. Three-Phase Fluidization A. Introduction B. Classification 1. Cocurrent Upflow of Gas–Liquid 2. Countercurrent Flow C. Hydrodynamics 1. Parameters 2. Pressure Drop and Holdup 3. Holdup Determination by Experiments D. Turbulent Contact Absorber VII. Heat Transfer A. Introduction B. Groups 1. Fluid–Particle Heat Transfer a. Steady State b. Unsteady State 2. Bed–Wall Heat Transfer [...]... Chlorination 2 Fluid Bed B Miscellaneous Uses VI Fluid Beds in Nuclear Fuel Reprocessing A Fuel Reprocessing 1 Methods a Aqueous Methods b Nonaqueous Methods c Combined Methods 2 Fluoride Volatility Process a Process Description b Fluid Bed B Novel Fluid Bed Fuel Reprocessing 1 Uranium–Aluminum/Uranium–Zirconium Fuel 2 Oxide Fuel 3 Carbide Fuel VII Fluidization in Waste Processing and Pollution Abatement A Fluid. .. Chlorination/Fluorination of Aluminum-Bearing Materials a Toth Process b Aluminum Trifluoride 8 Selective Chlorination for Nickel and Cobalt Recovery a Principles b Chlorination Studies Nomenclature References Chapter 3 Fluidization in Nuclear Engineering I Leaching A Fluidized Bed Leaching 1 General Description 2 Uses 3 Leaching Equipment B Design Aspects of Leaching Column C Staging 1 Staged Fluidization... Plasma Furnace III Plasma Fluidized Bed A Plasma–Solid Interactions 1 Heat Transfer to Solid 2 Solid Quenching B Plasma and Fluid Bed 1 DC Plasma Fluid Bed a Description b Testing 2 Inductively Coupled Plasma Fluid Bed C Plasma Fluidized Bed Characteristics 1 Interparticle Forces and Minimum Fluidization Velocity 2 Plasma Interaction with Fluid Bed a Tests b Results 3 Plasma Spouted Bed a Tests b Results... Third-Phase-Injected Type b Third-Phase-Generated Type E Applications 1 Fluidized Bed Electrodes in Copper Extraction 2 Fluidized Bed Electrodes in Nickel Extraction 3 Electrowinning of Cobalt, Silver, and Zinc a Cobalt b Silver c Zinc 4 Fluidized Bed Electrodes in Aqueous Waste Treatment 5 Miscellaneous Applications III Fluidized Bed Bioprocessing A Introduction B Bioassisted Processes 1 Microorganisms 2 Mineral... this expansion the bed can become much higher than its initial or incipient height In contrast, a gas fluidized bed is heterogeneous or aggregative or bubbling in nature and its expansion is limited, unlike what happens in a liquid fluidized bed It is seldom possible to observe particulate fluidization in a gas fluidized bed and aggregative fluidization in a liquid fluidized bed If the fluid © 1999 by... decreased, the bed pressure drop assumes its original path on a pressure drop versus velocity plot as long as the bed continues to be in a state of fluidization Retracing the path, as shown in Figure 1.3 by line DCG, indicates that the pressure drop obtained for a fixed bed during its settling is lower than that obtainable for increasing upward flow of gas Point C on line GCD is the transition point between... in Extractive Metallurgy B Plasma Fluid Bed Processes 1 Particulate Processes a Spheroidizing b Coating 2 Advanced Materials Processing a Fine Powders b Particle Nitriding c Diamond Synthesis C Salt Roasting in Spout Fluid Bed 1 Spout Fluid Bed Reactor 2 Performance Stability D Miscellaneous Applications 1 Carbothermy 2 Carburization 3 Gasification V Electrothermal Fluidized Bed A Description 1 Principle... Vibro Inclined Fluidized Bed a Gas Velocity b Heat Transfer F Spouted Bed Dryer G Internally Heated Dryer versus Inert Solid Bed Dryer 1 Internally Heated Bed 2 Inert Solid Bed 3 Characteristics a Performance b Residence Time c Performance Assessment H Applications 1 Iron Ore Drying 2 Miscellaneous Areas II Roasting A Fluidization in Pyrometallurgy 1 Industrial Noncatalytic Reactors 2 Early Fluid Bed. .. and a fluidized bed, and the velocity corresponding to this is the minimum fluidization velocity It may be observed that during increasing flow through the bed, there is no distinct point marking the transition, except that zone which corresponds to B–C with a peak The relatively high value of the pressure drop (∆P) along line AB in a fixed bed when the flow is in the laminar regime compared to line... 2 Fluid Bed a Reactor b Reaction Steps IV Pyrocarbon Coating A Reactor Choice 1 Suitability 2 Immersed Objects 3 Coating Classification B Classification of Pyrolytic Deposition 1 Nonmetallic Coating a Carbon Coating b Silicon Carbide 2 Fluid Bed © 1999 by CRC Press LLC a Coating in Fluid Bed b Coating Properties c Recommendations V Fluidization in Zirconium Extraction A Breaking of Zircon 1 Chlorination . graduated in Chemical Engineering in 1974 from A.C. College, University of Chennai, Chennai, India. He obtained his Ph.D. in Chemical Engineering in 1984 from the Indian Institute of Technology, . Recommendations V. Fluidization in Zirconium Extraction A. Breaking of Zircon 1. Chlorination 2. Fluid Bed B. Miscellaneous Uses VI. Fluid Beds in Nuclear Fuel Reprocessing A. Fuel Reprocessing 1. Methods a Constraints E. Vibro Fluidized Bed Dryer 1. Basics 2. Vibro Inclined Fluidized Bed a. Gas Velocity b. Heat Transfer F. Spouted Bed Dryer G. Internally Heated Dryer versus Inert Solid Bed Dryer 1. Internally