Fluidization, solids handling, and processing : industrial applications

906 Pages·1998·17.48 MB·English

by  Wen-ching Yang

FLUIDIZATION, SOLIDS
HANDLING, AND PROCESSING
Industrial Applications
Edited by
Wen-Ching Yang
Siemens Westinghouse Power Corporation
Pittsburgh, Pennsylvania
NOYES PUBLICATIONS
np
Westwood, New Jersey, U.S.A.
JMR 24-Sep-01
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
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
v
Contributors
John C. Chen Thomas B. Jones
Department of Chemical Department of Electrical
Engineering Engineering
Lehigh University University of Rochester
Bethlehem, PA Rochester, NY
Bryan J. Ennis S.B. Reddy Karri
E&G Associates Particulate Solid Research, Inc.
Nashville, TN Chicago, IL
Liang-Shih Fan George E. Klinzing
Department of Chemical Department of Chemical and
Engineering Petroleum Engineering
Ohio State University University of Pittsburgh
Columbus, OH Pittsburgh, PA
Leon R. Glicksman Ted M. Knowlton
Department of Architecture, Particulate Solid Research, Inc.
Building Technology Program Chicago, IL
Massachusetts Institute of
Technology Mooson Kwauk
Cambridge, MA Institute of Chemical Metallurgy
Adacemia Sinica
Beijing, People’s Republic of
China
ix
x Contributors
Jack Reese Joachim Werther
Department of Chemical Technical University Hamburg-
Engineering Harburg
Ohio State University Hamburg, Germany
Columbus, OH
Peter Wypych
Jens Reppenhagen Department of Mechanical
Technical University Hamburg- Engineering
Harburg University of Wollongong
Hamburg, Germany Wollongong, NSW, Australia
Ellen M. Silva Shang-Tian Yang
Department of Chemical Department of Chemical
Engineering Engineering
Ohio State University Ohio State University
Columbus, OH Columbus, OH
Gabriel I. Tardos Wen-Ching Yang
Department of Chemical Science and Technology Center
Engineering Siemens Westinghouse Power
City College of City University of Corporation
New York Pittsburgh, PA
New York, NY
Frederick A. Zenz
Richard Turton Process Equipment Modeling &
Department of Chemical Mfg. Co., Inc.
Engineering Cold Spring, NY
West Virginia University
Morgantown, WV
JMR- 24-Sep-01
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
vi
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.
JMR- 24-Sep-01
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
xi
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
JMR- 24-Sep-01