JMR 24-Sep-01 FLUIDIZATION, SOLIDS HANDLING, AND PROCESSING Industrial Applications np NOYES PUBLICATIONS Westwood, New Jersey, U.S.A. Edited by Wen-Ching Yang Siemens Westinghouse Power Corporation Pittsburgh, Pennsylvania Copyright © 1998 by Noyes Publications No part of this book may be reproduced or utilized in any form or by any means, elec- tronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without permission in writing from the Publisher. Library of Congress Catalog Card Number: 98-18924 ISBN: 0-8155-1427-1 Printed in the United States Published in the United States of America by Noyes Publications 369 Fairview Avenue, Westwood, New Jersey 07675 10 9 8 7 6 5 4 3 2 1 Library of Congress Cataloging-in-Publication Data Fluidization, solids handling, and processing : industrial applications / edited by Wen-Ching Yang. p. cm. Includes bibliographical references and index. ISBN 0-8155-1427-1 1. Fluidization. 2. Bulk solids flow. I. Yang, Wen-ching, 1939- TP156.F65F5828 1998 660' .284292 dc21 98-18924 CIP v PARTICLE TECHNOLOGY SERIES Series Editor: Liang-Shih Fan, Ohio State University FLUIDIZATION, SOLIDS HANDLING, AND PROCESSING: Edited by Wen-Ching Yang INSTRUMENTATION FOR FLUID-PARTICLE FLOWS: by S. L. Soo ix Contributors John C. Chen Department of Chemical Engineering Lehigh University Bethlehem, PA Bryan J. Ennis E&G Associates Nashville, TN Liang-Shih Fan Department of Chemical Engineering Ohio State University Columbus, OH Leon R. Glicksman Department of Architecture, Building Technology Program Massachusetts Institute of Technology Cambridge, MA Thomas B. Jones Department of Electrical Engineering University of Rochester Rochester, NY S.B. Reddy Karri Particulate Solid Research, Inc. Chicago, IL George E. Klinzing Department of Chemical and Petroleum Engineering University of Pittsburgh Pittsburgh, PA Ted M. Knowlton Particulate Solid Research, Inc. Chicago, IL Mooson Kwauk Institute of Chemical Metallurgy Adacemia Sinica Beijing, People’s Republic of China JMR- 24-Sep-01 x Contributors Jack Reese Department of Chemical Engineering Ohio State University Columbus, OH Jens Reppenhagen Technical University Hamburg- Harburg Hamburg, Germany Ellen M. Silva Department of Chemical Engineering Ohio State University Columbus, OH Gabriel I. Tardos Department of Chemical Engineering City College of City University of New York New York, NY Richard Turton Department of Chemical Engineering West Virginia University Morgantown, WV Joachim Werther Technical University Hamburg- Harburg Hamburg, Germany Peter Wypych Department of Mechanical Engineering University of Wollongong Wollongong, NSW, Australia Shang-Tian Yang Department of Chemical Engineering Ohio State University Columbus, OH Wen-Ching Yang Science and Technology Center Siemens Westinghouse Power Corporation Pittsburgh, PA Frederick A. Zenz Process Equipment Modeling & Mfg. Co., Inc. Cold Spring, NY vi Preface This volume, Fluidization, Solids Handling, and Processing, is the first of a series of volumes on “Particle Technology” to be published by Noyes Publications with L. S. Fan of Ohio State University as the consulting editor. Particles are important products of chemical process industries spanning the basic and specialty chemicals, agricultural products, pharmaceuticals, paints, dyestuffs and pigments, cement, ceramics, and electronic materials. Solids handling and processing technologies are thus essential to the operation and competitiveness of these industries. Fluidization technology is employed not only in chemical production, it also is applied in coal gasification and combustion for power generation, mineral processing, food processing, soil washing and other related waste treatment, environmental remediation, and resource recovery processes. The FCC (Fluid Catalytic Cracking) technology commonly employed in the modern petroleum refineries is also based on the fluidization principles. There are already many books published on the subjects of fluidiza- tion, solids handling, and processing. On first thought, I was skeptical about the wisdom and necessity of one more book on these subjects. On closer examination, however, I found that some industrially important subjects were either not covered in those books or were skimpily rendered. It would be a good service to the profession and the engineering community to assemble all these topics in one volume. In this book, I have invited recognized experts in their respective areas to provide a detailed treatment JMR 24-Sep-01 Preface vii of those industrially important subjects. The subject areas covered in this book were selected based on two criteria: ( i) the subjects are of industrial importance, and (ii) the subjects have not been covered extensively in books published to date. The chapter on fluidized bed scaleup provides a stimulating approach to scale up fluidized beds. Although the scaleup issues are by no means resolved, the discussion improves the understanding of the issues and provides reassessments of current approaches. The pressure and tem- perature effects and heat transfer in fluidized beds are covered in separate chapters. They provide important information to quantify the effects of pressure and temperature. The gas distributor and plenum design, critical and always neglected in other books, are discussed in detail. For some applications, the conventional fluidized beds are not necessarily the best. Special design features can usually achieve the objective cheaper and be more forgiving. Two of the non-conventional fluidized beds, recirculat- ing fluidized beds with a draft tube and jetting fluidized beds, are intro- duced and their design approaches discussed. Fluidized bed coating and granulation, applied primarily in the pharmaceutical industry, is treated from the fluidization and chemical engineering point of view. Attrition, which is critical in design and operation of fluidized beds and pneumatic transport lines, is discussed in detail in a separate chapter. Fluidization with no bubbles to minimize bypassing, bubbleless fluidization, points to potential areas of application of this technology. The industrial applica- tions of the ever-increasingly important three-phase fluidization systems are included as well. The developments in dense phase conveying and in long distance pneumatic transport with pipe branching are treated sepa- rately in two chapters. The cyclone, the most common component em- ployed in plants handling solids and often misunderstood, is elucidated by an experienced practitioner in the industry. The book is concluded with a discussion on electrostatics and dust explosion by an electrical engineer. This book is not supposed to be all things to all engineers. The primary emphasis of the book is for industrial applications and the primary audience is expected to be the practitioners of the art of fluidization, solids handling, and processing. It will be particularly beneficial for engineers who operate or design plants where solids are handled, transported, and pro- cessed using fluidization technology. The book, however, can also be useful as a reference book for students, teachers, and managers who study particle technology, especially in the areas of application of fluidization technology and pneumatic transport. JMR- 24-Sep-01 viii Preface I’d like to take this opportunity to thank Professor Fan who showed confidence in me to take up this task and was always supportive. I’d also like to thank the authors who contributed to this book despite their busy schedules. All of them are recognized and respected experts in the areas they wrote about. The most appreciation goes to my wife, Rae, who endured many missing weekends while I worked alone in the office. Pittsburgh, Pennsylvania Wen-Ching Yang February, 1998 NOTICE To the best of our knowledge the information in this publication is accurate; however the Publisher does not assume any responsibility or liability for the accuracy or completeness of, or consequences arising from, such information. This book is intended for informational purposes only. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the Publisher. Final determination of the suitability of any information or product for use contemplated by any user, and the manner of that use, is the sole responsibility of the user. We recommend that anyone intending to rely on any recommendation of materials or procedures mentioned in this publication should satisfy himself as to such suitability, and that he can meet all applicable safety and health standards. xi Contents 1 Fluidized Bed Scale-up 1 Leon R. Glicksman 1.0 INTRODUCTION 1 2.0 REACTOR MODELING: BED DIAMETER INFLUENCE 4 3.0 INFLUENCE OF BED DIAMETER ON HYDRODYNAMICS 10 3.1 Bubbling Beds 10 3.2 Mixing 20 3.3 Influence of Bed Diameter on Circulating Fluidized Beds 22 3.4 Flow Transition 25 4.0 EXPERIMENTAL MEANS TO ACCOUNT FOR SCALE-UP: USE OF SCALE MODELS 26 4.1 Development of Scaling Parameters 27 4.2 Governing Equations 29 4.3 Fluid-Solid Forces 35 4.4 Spouting and Slugging Beds 38 5.0 SIMPLIFIED SCALING RELATIONSHIPS 39 5.1 Low Reynolds Number 39 5.2 High Reynolds Numbers 41 5.3 Low Slip Velocity 42 5.4 General Case 43 5.5 Range of Validity of Simplified Scaling 44 JMR- 24-Sep-01 xii Contents 6.0 FURTHER SIMPLIFICATIONS IN THE SCALING RELATIONSHIP 51 6.1 Viscous Limit 51 6.2 Other Derivations for Circulating Fluidized Beds 54 6.3 Deterministic Chaos 55 7.0 DESIGN OF SCALE MODELS 56 7.1 Full Set of Scaling Relationships 56 7.2 Design of Scale Models Using the Simplified Set of Scaling Relationships 61 8.0 EXPERIMENTAL VERIFICATION OF SCALING LAWS FOR BUBBLING BEDS 65 8.1 Hydrodynamic Scaling of Bubbling Beds 65 8.2 Verification of Scaling Relationships for Bubbling and Slugging Beds 69 8.3 Verification of Scaling Laws for Spouting Beds 75 8.4 Verification of Scaling Relationships for Pressurized Bubbling Beds 76 9.0 APPLICATIONS OF SCALING TO COMMERCIAL BUBBLING FLUIDIZED BED UNITS 80 10.0 HYDRODYNAMIC SCALING OF CIRCULATING BEDS 91 11.0 CONCLUSIONS 100 ACKNOWLEDGMENTS 102 NOTATIONS 103 REFERENCES 104 2 Pressure and Temperature Effects in Fluid-Particle Systems 111 Ted M. Knowlton 1.0 INTRODUCTION 111 1.1 Minimum Fluidization Velocity 113 1.2 Bed Voidage and Bed Expansion 120 1.3 Bubbles in Fluidized Beds 124 1.4 Bubble Size and Frequency 125 1.5 Bed-to-Surface Heat Transfer Coefficient 129 1.6 Entrainment and Transport Disengaging Height 131 1.7 Particle Attrition at Grids 134 1.8 Particle Attrition in Cyclones 136 1.9 Jet Penetration 137 1.10 Regime Transitions 139 1.11 Cyclone Efficiency 146 NOTATIONS 147 REFERENCES 149 [...]... 1.3Umf;O = 1.5Umf;V = 1.8Umf; Tdenotes with tubes (From Glicksman and McAndrews, 1985.) 20 Fluidization, Solids Handling, and Processing 7.615.2 30.5 122 61 WALL SPACING Dr CH Figure 15 Visible bubble flow Qb.lmf=76 cm, probeheight=46 cm x= 1.3Umf; O = 1.5Umf; V = 1.8Umf; T denotes with tubes Experiment uncertainty = 20% (From Glicksman and McAndrews, 1985.) 3.2 Mixing Van Deemter (1980) surveyed data on... with smaller width 24-Sep-2001 JMR 18 Fluidization, Solids Handling, and Processing 0.9 0.8 0.7 0.6 ~ 0.5 0.4 0.3 0.2 0 0 7.615.2 30.5 122.0 61.0 WALL SPACING Dr CH Figure 13 Variation of bubble rise velocity with wall spacing; 1 standard deviation~ Tdenoteswith ~bes 0: tjJ = Ub/(gD~J/2;x: tjJ = (Jb-Qb/(gD~J/2; : tjJ = Ub- (U -Um,J/(gD~J/2 (From Glicksmanand McAndrews,1985.) Fluidized Bed Scale-up... patterns, undesirable solid mixing patterns and physical operating problems (Matsen, 1985) In the synthol CFB reactors constructed in South Africa, first scale-up from the pilot plant increased the gas throughput by a factor of 500 Shingles and McDonald (1988) describe the severe problems initially encountered and their resolution 1 2 Fluidization, Solids Handling, and Processing In some scaled up fluidized... hydraulic diameter while the solids axial mixing was higher than that predicted using the hydraulic diameter 6 FROM O CONVERSION C o FR)M ( PRESENT RTD DATA TESTS INVESTIGATION ) u «{H O.i I 4 1 I 4 D,m Figure 5 Mass transfer unit for ozone conversion for different bed diameters (From Van Swaaij and Zuiderweg, 1972.) 9-Oct-2001 JMR 10 Fluidization, Solids Handling, and Processing Bauer et al (1981)... NAllROW-RANGE SILICA 10 0 0.1 0.5 t.O 5 BED D:AMETER, m 9-Oct-2001 JMR 12 Fluidization, Solids Handling, and Processing Figure DeGroot, 8 Effective 1967.) axial diffusivity coefficients for solids mixing (From Fluidized Bed Scale-up 13 Weather (1974) measured the bubble characteristics in cylindrical beds of diameters 100, 200, 450 and 1000 mm, respectively, for fine particles with a mean particle diameter... Characterization 556 8.2 Improving Fluidization by Particle Size Adjustment 562 9.0 WHY BUBBLING AND NOT PARTICULATE FLUIDIZATION 569 9.1 The Energy-Minimized Multiscale (EMMS) Model 570 9.2 Reconciling L/S and G/S Systems 573 10.0 EPILOGUE 576 NOTATIONS 576 REFERENCES 578 9 Industrial Applications of Three-Phase Fluidization Systems 582 Jack... measurements of overall bed density in the reactor 24-Sep-2001 JMR 4 Fluidization, Solids Handling, and Processing As Matsen expresses it, after over a half a century of scale-up activity in the chemical process industry, “such scale-up is still not an exact science but is rather a mix of physics, mathematics, witchcraft, history and common sense which we call engineering.” (Matsen, 1995.) A complete... synthesis The ozone decomposition can be run at low pressures and temperatures and can be rate-controlled in the same way and by the same catalyst as the reaction under development Frye and coworkers used three beds of 2 inch, 8 inch and 30 inch diameter, respectively, to study the size influence We should interject a caution that the use of pressures and temperatures different than the actual reaction may... distance r from the vessel center line in a height of 30 cm above the distributor in beds of different diameters DB (uo = 9 cm/sec, H = 50 cm) (From Werther, 1974.) 9-Oct-2001 JMR 14 Fluidization, Solids Handling, and Processing , . Cataloging-in-Publication Data Fluidization, solids handling, and processing : industrial applications / edited by Wen-Ching Yang. p. cm. Includes bibliographical references and index. ISBN 0-8155-1427-1 1. Fluidization. . emphasis of the book is for industrial applications and the primary audience is expected to be the practitioners of the art of fluidization, solids handling, and processing. It will be particularly. spanning the basic and specialty chemicals, agricultural products, pharmaceuticals, paints, dyestuffs and pigments, cement, ceramics, and electronic materials. Solids handling and processing technologies