ADVANCES IN WATERDESALINATION

WILEY SERIES ON ADVANCES IN WATERDESALINATION

NOAM LIOR, Series Editor

Editorial Board

Miriam Balaban

Editor in Chief of Desalination and Water Treatment;Secretary General of the European Desalination Society

University Campus Bio-Medico of Rome, Faculty of Engineering; ItalyCenter for Clean Water and Energy, Department of Mechanical Engineering,MIT, Cambridge, MA, USA

Mohammad A. Darwish

Professor Emeritus, Kuwait University, Kuwait

Consultant, Qatar Environment and Energy Research Institute, Doha, Qatar

Osamu Miyatake

Professor Emeritus of Kyushu University, JapanSpecial Advisor of JDA (Japan Desalination Association)Fukuoka, Japan

Shichang Wang

Professor, Tianjin University, Tianjin, China

Mark Wilf

Membrane Technology Consultant, San Diego, CA, USA

ADVANCES IN WATERDESALINATION

Edited by

Noam LiorUniversity of Pennsylvania

A JOHN WILEY & SONS, INC., PUBLICATION

Cover Images: (large photo) © Airyelf/iStockphoto; (circle 1) © BlankaBoskov/iStockphooto; (circle 2) Photograph shows the 127 million m3/year ROdesalination plant in Hadera, Israel. Courtesy of IDE Technologies, the builder andoperator of the plant; (circle 3) Photograph shows the 23,500 m3/day per unit MSFdesalination plant in Al-Jobail, Saudi Arabia. Courtesy of Sasakura Engineering Ltd., thebuilder of the plant; (circle 4) Line art depicting filtration.

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Library of Congress Cataloging-in-Publication Data:

Advances in water desalination / edited by Noam Lior.p. cm.

Includes bibliographical references and index.ISBN 978-0-470-05459-8 (hardback)

1. Saline water conversion. I. Lior, Noam.TD479.A36 2012628.1′67–dc23

2012006128

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

CONTENTS

Preface viiNoam Lior

Introduction to the Book Series ixNoam Lior

About the Authors xi

1. Water Desalination Revisited in Changing Physical and EconomicEnvironments 1Yehia M. El-Sayed

2. Environmental and Performance Aspects of Pretreatment andDesalination Technologies 79Sabine Lattemann,∗ Sergio G. Salinas Rodriguez, Maria D. Kennedy,Jan C. Schippers, and Gary L. Amy

3. Economic Aspects of Water Desalination 197Amitzur Barak

4. Advances in Hollow-Fiber Reverse-Osmosis Membrane Modules inSeawater Desalination 309Atsuo Kumano

5. Adsorption–Desalination Cycle 377Anutosh Chakraborty, Kyaw Thu, Bidyut Baran Saha,∗ and Kim Choon Ng∗

6. Advanced Instrumentation, Measurement, Control, and Automation(IMCA) in Multistage Flash (MSF) and Reverse-Osmosis (RO) WaterDesalination 453Noam Lior,∗ Ali El-Nashar, and Corrado Sommariva

Index 659

∗Corresponding author.

v

PREFACE

This volume contains a wide spectrum of principal and timely information about(1) advances in fundamentals of desalination analysis and design when taking intoconsideration the increasing concerns about environmental and fuel cost effectson the processes, (2) an evaluation of the state of the art of pretreatment anddesalination technologies considering environmental and performance aspects,(3) a critical comprehensive survey of the economic aspects of water desalination,(4) a review of advances in hollow-fiber reverse-osmosis membrane modules,(5) an introduction and review of the emerging adsorption desalination process,and (6) a comprehensive review of advanced instrumentation, measurements,control, and automation in the MSF (Multi-Stage Flash) and RO (ReverseOsmosis) desalination processes.

Perhaps the current main leading challenge in water desalination is its sustain-ability. The first three chapters in the book address two of the three sustainabilitypillars: environmental impact and economics. Economics became a growing con-cern due to the rapidly increasing and wildly fluctuating prices of energy, which isbecoming a more dominant fraction of the produced water cost.

I note with great sorrow that the author of Chapter 1, Dr. Professor YehyaEl-Sayed, has passed away before the printing of this book. As one of the world’sleading and well-acknowledged thermodynamicists, he brought the science to engi-neering practice in general and to water desalination in particular, especially in hisseminal work on applications of exergy and exergo-economic analysis to this field.His life-work and this chapter demonstrates his foresight in dealing scientificallywith water desalination sustainability, and will remain a permanent tribute to hismemory.

I would like to acknowledge the essential contributions of the chapter authorswho shared with us their precious knowledge and experience, of the book seriesEditorial Board members who are international leading desalination experts,Ms. Miriam Balaban, Dr. Professor Mohamed Ali Darwish, Dr. Professor OsamuMiyatake, Dr. Professor Shichang Wang and Dr. Mark Wilf who providedvaluable guidance and review, and of Dr. Arza Seidel of John Wiley & Sonswho has patiently and professionally overseen the creation of this book series andvolume.

vii

viii PREFACE

Some material for Chapter 1 is not included in the book (in its various formats)and may be downloaded at http://booksupport.wiley.com. For more informationabout Wiley products, including a variety of print and electronic formats, visitwww.wiley.com.

Professor Noam LiorUniversity of PennsylvaniaPhiladelphia, PA 19104-6315, USAlior@seas.upenn.eduEditor-in-ChiefPhiladelphia, 17 March 2012

INTRODUCTION TO THE BOOK SERIESADVANCES IN WATER DESALINATION

Rapidly increasing scarcity of water usable for drinking, irrigation, industry, andgeneral sanitation, caused by rising use and pollution of existing fresh watersources, has created an enormous rise (lately of around 12%/year) in water desali-nation. Water desalination consists of separation processes that produce new freshwater from seawater and other water sources which are too saline for use. Largecommercial scale desalination began in 1965 and had a worldwide capacity ofonly about 8000 m3/day in 1970. It now produces about 72 million m3/day ofdesalted water by about 16,000 facilities worldwide. Within 10 years, productionis forecasted to triple with an expected investment of around $60 billion.

Water desalination is accomplished by a variety of different technologies,which are gradually changing to reduce capital costs, energy consumption andenvironmental impacts. It consumes large amounts of energy and materials,and has an associated important and increasingly recognized impact on theenvironment. Research and development, improved construction, operation, costallocation in multi–purpose plants, and financing methods, and education andinformation exchange must continue to be advanced to reduce the cost of thewater produced and improve process sustainability.

Advances in Water Desalination is designed to meet the knowledge needs inthis rapidly advancing field. One book volume is published per year, and contains5–7 invited, high quality timely reviews, each treating in depth a specific aspect ofthe desalination and related water treatment field and the chapters are written andreviewed by top experts in the field. All aspects are addressed and include science,technology, economics, commercialization, environmental and social impacts, andsustainability.

The series will be useful for desalination practitioners in industry and business,scientists and researchers, and students.

The series is advised and directed by an international Editorial Board of desali-nation and water experts from academia and industry.

ix

x INTRODUCTION TO THE BOOK SERIES

I am grateful to Dr. Arza Seidel of John Wiley & Sons who has patiently andprofessionally overseen the creation of this book series.

Professor Noam LiorUniversity of PennsylvaniaPhiladelphia, PA 19104-6315, USAlior@seas.upenn.eduEditor-in-ChiefPhiladelphia, 17 March 2012

ABOUT THE AUTHORS

Prof. Gary Amy is Director of the Water Desalinationand Reuse Research Center and Named Professor of Envi-ronmental Science and Engineering at the King AbdullahUniversity of Science and Technology (KAUST) in theKingdom of Saudi Arabia.

Prof. Amy’s research focuses on membrane technol-ogy, innovative adsorbents, ozone/advanced oxidation, riverbank filtration and soil aquifer treatment, natural organicmatter and disinfection by-products, and organic and inor-ganic micropollutants.

Dr. Amitzur Ze’ev Barak born 1938 in Israel, got both hisB.Sc. in Mechanical & Energy Engineering/Nuclear Engi-neering [1960] and his Doctor of Sciences-in-Technology,Civil Engineering/Hydro-Sciences [1974] at the Technion,the Israel Institute of Technology. Joined the desalinationcommunity [1962] as the Research Desalination Engineerat the IDE-Israel Desalination Engineering Ltd. Coinventorand development-manager of two low-temperature evapo-rative desalination processes—LTMVC [mechanical vaporcompression, 1964] and LTMED [multieffect-distillation,1969]. For these activities, he received the Israeli “Prime-

Minister Award for Applied Research” [1976].Manager of the Thermal Desalination R&D Department at IDE Ltd

[1968–1974].Manager of the “Joint US-Israel Desalination Program,” and director of all the

Israeli governmental R&D activities on desalination [1976–1981].Senior staff engineer for planning at the Israeli Atomic Energy Commission

[1982–2003]. Since 2003, Professor of Chemical Engineering, Civil Engineering,and Mechanical Engineering at the Ariel University Center of Samaria, Israel.Consultant to the IAEA (International Atomic Energy Agency), the CERN, anddozen other entities on energy and desalination. Published over 60 papers and hassix patents on desalination and solar energy.

xi

xii ABOUT THE AUTHORS

Anutosh Chakraborty received his B.Sc. Eng. fromBUET, Bangladesh, in 1997. He obtained his M. Engg.and Ph.D. degrees from the National University of Singa-pore (NUS) in 2001 and 2005, respectively. He workedas a JSPS Fellow at the interdisciplinary Graduate Schoolof Engineering Sciences of Kyushu University, Japan.At present, he is working at the School of Mechanicaland Aerospace Engineering, Nanyang Technological Uni-versity (NTU), Singapore, as an Assistant Professor. Hisresearch interests focus on micro/nanoscale transport phe-nomena, thin-film thermoelectric device; adsorption ther-

modynamics, adsorption cooling, gas storage, and desalination; and CO2-basedcooling system. At present, Dr. Chakraborty has published about 100 articlesin peer-reviewed journals and international conference proceedings and holds sixpatents.

Dr. Ali El Nashar is a mechanical engineer withspecialization in the fields of energy and desalination andwith a special interest in solar desalination and powergeneration. He received his Ph.D. degree in nuclearengineering from the Queen Mary College, Universityof London, UK, in 1968. His work experience coversapplied research and development work at both academicand industrial institutions. He has been involved inteaching and research at several academic institutions inEgypt, UK, and USA, among them are the Universityof Alexandria and University of Mansoura in Egypt; the

Queen Mary College, London University and Lanchester Polytechnic in the UnitedKingdom; and the Clemson University and Florida Institute of Technology in theUnited States. He has worked as the manager of cogeneration and desalinationdepartment at the Abu Dhabi Water & Electricity Authority (ADWEA) from1982 to 2002, where his department participated in the commissioning of newdesalination and power plants as well as monitoring the performance of existingplants operated by the ADWEA. He was also in charge of the solar desalinationresearch program in the ADWEA during this period, where he supervised theinstallation, commissioning, and testing of the solar desalination demonstrationplant in Umm Al Nar, which was designed and operated as a part of a jointresearch program with Japan’s New Energy Development Organization (NEDO).He has been a member of several professional organizations, including the ASME,IDA, and ISE, and the editor of the IDA, Energy, and ISE. He has consultedfor a number of international organizations, including the United NationsEnvironmental Program (UNEP); Arab Agency for Industrial Development

ABOUT THE AUTHORS xiii

(AAID); Technology International, Inc. (USA); CH2M-Hill, Inc. (USA); ScienceApplications, Inc. (USA); Dow Chemical Europe (Switzerland); and IndustrialCenter for Water & Energy Systems (ICWES), Abu Dhabi. Dr. El-Nashar hasmore than 50 published papers, reports, and book chapters in his field of interest.

Dr. Yehia El-Sayed 1928–2010. Yehia El-Sayed wasborn in Alexandria, Egypt, on September 13, 1928. Hereceived his bachelor’s degree from Alexandria Univer-sity and his doctorate in Mechanical Engineering fromManchester University in England. He taught and con-ducted research at Assiut University (Egypt), KansasState University, Dartmouth College, Glasgow Univer-sity (Scotland), Tripoli University (Libya), and the Mas-sachusetts Institute of Technology. His legacy persists inthe thousands of students and colleagues whose careersand intellectual development he has influenced. He wasa recognized international authority in desalination, ther-

modynamics, and thermoeconomics. He authored two books and numerous scien-tific papers. A Life Fellow of the American Society of Mechanical Engineering,he was a two-time recipient of ASME’s prestigious Edward F. Obert Award, inaddition to a Best Paper Award from the International Desalination Association.Dr. El-Sayed’s contributions brought the fundamentals of science to usefulness inengineering practice across the spectrum of energy conversions systems, providingprinciples for optimizing their technical and economic efficiency.

Editor-in-Chief’s note: Yehia El-Sayed submitted his chapter but regrettablypassed away before the publication of this book. His wisdom, kindness, and friend-ship will be missed by the desalination and thermodynamics scientific communities,including me.

Prof. Maria D Kennedy Ph.D., is the Professor of WaterTreatment Technologies at UNESCO-IHE. She is a boardmember of the European Desalination Society. She has 18years of research experience and currently specializes inresearch and development in the field of membrane tech-nology. Her research areas of interest include membranefouling (indices), scaling and cleaning, and modeling ofmembrane systems. She has been involved in internationaltraining projects in Israel (West Bank), Jordan, Oman, St.Maarten, and Yemen in the field of desalination and waterreuse.

xiv ABOUT THE AUTHORS

Dr. Atsuo Kumano is a professional engineer Japan, andin charge of technical matters in the Desalination Mem-brane Department in Toyobo Co., Ltd. Dr. Kumano’sresearch and development focus on membrane technol-ogy and its engineering, for water treatment membranessuch as reverse osmosis membrane for seawater desali-nation, and wastewater treatment including hollow fibreconfiguration module analysis.

Dr. Kumano holds a Ph.D. in Chemical Science andEngineering from Kobe University, Japan, 2011; an M.S.in Environmental Engineering from Osaka University,

Japan, 1983; and a B.S. in Environmental Engineering from Osaka University,Japan, 1981.

Dr. Sabine Lattemann is a part-time Research Scientistat the Water Desalination and Reuse Center (WDRC) ofthe King Abdullah University of Science and Technology(KAUST) in the Kingdom of Saudi Arabia.

Sabine has over 10 years of experience in environ-mental impact assessment (EIA) studies. Her main areasof interest include the desalination of seawater, offshorewind energy development projects, and maritime ship-ping impacts. From 2007 to 2010, Sabine worked on thetopic of environmental impacts and life cycle assessmentof seawater desalination plants within the European

research project “MEDINA.” From 2004 to 2007, she chaired the environmentalworking group of the World Health Organization Project “Desalination for safewater supply.”

Sabine holds a Postgraduate Diploma in Marine Science from Otago University(New Zealand), an M.Sc. in Marine Environmental Science from the Universityof Oldenburg (Germany), and a doctorate degree from the UNESCO-IHE Institutefor Water Education and Delft University of Technology (The Netherlands).

Dr. Noam Lior is a Professor of Mechanical Engineeringand Applied Mechanics at the University of Pennsylvania,where he is also a member of the Graduate Group of Inter-national Studies, Lauder Institute of Management andInternational Studies (MA/MBA program); of the Insti-tute for Environmental Science; and of the Initiative forGlobal Environmental Leadership (IGEL) at the Whar-ton Business School. He did his Ph.D. work on waterdesalination at the Seawater Conversion Laboratory ofthe University of California, Berkeley, and thus startedactive research, teaching, and consulting in this field in

1966. His editorships include the following.

ABOUT THE AUTHORS xv

Editor-in-Chief:

Advances in Water Desalination book series, John Wiley, since 2006.Energy, The International Journal , 1998–2009.

Board of Editors Member:

Desalination, The International Journal of Desalting and Water Purification ,since 1988;

Energy Conversion and Management Journal , since 1994;

Desalination and Water Treatment—Science and Engineering , journal, Desali-nation Publications–International Science Services, since 2008;

Frontiers of Energy and Power Engineering , Springer, since 2008;

The Energy Bulletin , an international quarterly published by the InternationalSustainable Energy Development Center (ISEDC, under UNESCO auspices),Moscow, Russian Federation, since 2011;

Thermal Science and Engineering Journal (Japan), 1999–2008;

The ASME Journal of Solar Energy Engineering , 1983–1989;

The International Desalination & Water Reuse Quarterly , 1997–2003.

He has more than 350 technical publications, many of which are in the energyand desalination fields, and is the editor of the book Measurements and Control inWater Desalination (Elsevier, 1986).

Kim Choon Ng is working as a Professor at the Mechan-ical Engineering Department of the National University ofSingapore. Professor Kim Choon specializes in the designof thermally driven adsorption cycles for desalination andcooling, with the objective of achieving a specific energyconsumption of less than 1.5 kWh per cubic meter. Thenewly patented cycle of AD + MED desalination planthas the highest water production rates to date, producingpotable water from either seawater or brackish-water usingonly low temperature waste heat. The novelties of the AD+ MED cycle are that (i) it can operate with MED stages

at temperatures below the ambient conditions with seven to nine stages, (ii) it hasalmost no major moving parts, (iii) it has minimal fouling because the temperatureof heat source is from 50 to 80 ◦C, and (iv) it is environmental friendly. In addition,he employs the highly efficient ozone microbubble systems for the pretreatmentof the feed water. His main research interests are adsorption thermodynamics,adsorption desalination and cooling, and microbubble treatment of wastewaterwith ozone. He has published more than 250 articles in peer-reviewed journalsand international conference proceedings. He has edited three books and holds10 patents.

xvi ABOUT THE AUTHORS

Bidyut Baran Saha obtained his B.Sc. (Hons.) and M.Sc.degrees from Dhaka University of Bangladesh in 1987and 1990, respectively. He received his Ph.D. in 1997from Tokyo University of Agriculture and Technology,Japan. He worked as an Associate Professor at the inter-disciplinary Graduate School of Engineering Sciences ofKyushu University until 2008. He worked as a SeniorResearch Fellow at the Mechanical Engineering Depart-ment of the National University of Singapore before join-ing the Mechanical Engineering Department of KyushuUniversity in 2010 as a Professor. He also holds a Profes-

sor position at the Thermophysical Properties Division of the International Institutefor Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University. His mainresearch interests are thermally powered sorption systems, adsorption desalination,heat transfer enhancement, and energy efficiency assessment. He has publishedmore than 200 articles in peer-reviewed journals and international conference pro-ceedings. He has edited three books and holds seven patents. Recently, he servedas the Guest Editor for the Heat Transfer Engineering journal for a special issue onthe Recent Developments of Adsorption Technologies for Energy Efficiency andEnvironmental Sustainability. He is also serving as the Managing Guest Editor ofApplied Thermal Engineering . He worked as the General Chairman for the Innova-tive Materials for the Processes in Energy Systems (IMRES) for Fuel Cells, HeatPumps and Sorption Systems, 2010 Singapore, and will organize IMPRES2013 atFukuoka, Japan.

Sergio G Salinas Rodriguez Ph.D., M.Sc, is a Lecturerin Water Treatment Technology at UNESCO-IHE. He hassix years of experience in research and in integrated mem-brane systems. He has performed research in the fields offouling indices and organic matter characterization forseawater reverse osmosis systems.

Prof. Jan C Schippers Ph.D., M.Sc, is a member ofthe Water Supply Group at UNESCO-IHE and a pro-fessor at the Wageningen University. He has extensiveprofessional experience in drinking and industrial watersupply projects in Morocco, Qatar, Libya, Gabon, CapeVerde, Namibia, Uzbekistan, Chile, France, and manyother countries. Prof. Schippers is the past president ofthe European Desalination Society and the chairman ofscientific and program committees of numerous interna-tional conferences and workshops of the IWA and EDS.

ABOUT THE AUTHORS xvii

Dr. Corrado Sommariva is a consultant of internationalreputation. He is presently the Managing Director of theILF Consulting Engineers, Middle East, and the head ofthe worldwide desalination activities of the ILF. Dr. Som-mariva has experience in both thermal, reverse osmosisand wastewater system and has served in all the majordesalination developments in the Middle East in variousroles. Dr. Sommariva has a Ph.D. in Chemical Engineeringfrom Genoa University and a diploma in Management fromLeicester University.

Dr. Sommariva has served in the IDA board in the past12 years. He has served as the first VP in 2003–2004. Furthermore, Dr. Sommarivaserved in the European Desalination Society (EDS) board for the past 14 years andhas served as the president in the year 2004–2005.

Within his main activities in IDA, Dr. Sommariva served as chairman of the affil-iate committee and started the humanitarian outreach initiative that has culminatedwith the establishment of the humanitarian committee in the IDA.

Dr. Sommariva has been the Chairman of the WHO committee for the estab-lishment of safe drinking water from desalination and the Technical Co-Chair ofthe IDA World Congress in Dubai. He is an honorary Professor at the Genoa andL’Aquila Universities, where he holds regular courses on desalination and water-reuse-related matters. Dr. Sommariva also holds regular courses with the IDA andthe Bushnaq academy.

Dr. Sommariva has published over 50 papers on desalination covering leadingedge research and economics and two books on desalination management andeconomics and project financing.

Starting from a very technical background, he has worked for the past 20 yearson desalination in various roles. He joined the ILF in 2009 after working nineyears with Mott MacDonald, where he has been leading the desalination and watertreatment group as the Managing Director of Generation, Middle East.

Kyaw Thu received his Ph.D. from the National Universityof Singapore (NUS), Singapore, in 2010 and B.E. (Mechan-ical Engineering) from the Yangon Technological Univer-sity (Y.T.U.), Myanmar, in 2004. At present, he is workingas a Research Scientist at the Water Desalination and ReuseCenter, King Abdullah University of Science and Tech-nology (KAUST). His research areas include adsorptionscience, theoretical and experimental analysis of thermallyactivated adsorption and absorption cycles for cooling anddesalination, heat and mass transfer and energy efficiency ofHVAC systems, Combined Heat and Power (CHP) Cycles,and solar thermal engineering.

CHAPTER 1

Water Desalination Revisited inChanging Physical and EconomicEnvironments

YEHIA M. EL-SAYED∗

1.1 Introduction 31.1.1 Past and Present Desalination 31.1.2 The Emerged Concern 41.1.3 The Emerged Energy Analysis Methodologies 5

1.2 The Methodology Used in this Study 61.2.1 Improved Thermodynamic Analysis 6

1.2.1.1 The Exergy Function 71.2.2 Improved Costing Analysis 8

1.2.2.1 The Quantification of the Manufacturing and OperationResources for a Device 8

1.2.2.2 Correlating the Manufacturing Resources of a Device inTerms of Thermodynamic Variables 9

1.2.3 Enhanced Optimization 101.2.3.1 Two Simplifying Assumptions 101.2.3.2 The Conditions of Device-by-Device Optimization 111.2.3.3 The Form of Ai min and Di of a Device 121.2.3.4 Convergence to System Optimum 131.2.3.5 Optimization of System Devices by One Average

Exergy Destruction Price 131.2.3.6 Global Decision Variables 14

1.3 The Scope of Analysis 141.3.1 Desalination Related to Physical and Economic Environments 141.3.2 The Systems Considered 15

∗Dr. El-Sayed has regrettably passed away prior to the publication of this chapter. Final proofreadingand some updating were done by the Editor. A tribute to his life was published as Testimonial, YehiaM. El-Sayed, Energy 36 2315 (2011).

Advances in Water Desalination, First Edition. Edited by Noam Lior.© 2013 John Wiley & Sons, Inc. Published 2013 by John Wiley & Sons, Inc.

1

2 WATER DESALINATION REVISITED IN CHANGING PHYSICAL AND ECONOMIC ENVIRONMENTS

1.4 The Analyzed Systems in Detail 341.4.1 Gas Turbine/Multistage Flash Distillation Cogeneration

Systems 341.4.1.1 Flow Diagram 341.4.1.2 Major Features of the Results 34

1.4.2 The Simple Combined Cycle Systems 351.4.2.1 Flow Diagram 351.4.2.2 Major Features of the Results 35

1.4.3 Vapor Compression Systems Driven by the Figure 1.2 SimpleCombined Cycle 361.4.3.1 Flow Diagrams 361.4.3.2 Major Features of the Results 36

1.4.4 Reverse Osmosis Desalination Systems Driven by the Figure 1.2Simple Combined Cycle 361.4.4.1 Flow Diagrams 361.4.4.2 Major Features of the Results 40

1.4.5 Photovoltaic/Reverse-Osmosis (PV/RO) Solar Systems 411.4.5.1 Flow Diagram 411.4.5.2 Major Features of Results 41

1.4.6 Photovoltaic/Electrodialysis Solar System 421.4.6.1 Major Features of the Results 42

1.4.7 Osmosis Power Systems 421.4.7.1 Flow Diagram 421.4.7.2 Major Features of the Results 44

1.4.8 Future Competitiveness of Combined Desalination Systems 451.4.8.1 Prediction Criteria 451.4.8.2 Predicted Competitiveness 45

1.5 Recommended Research Directions 461.5.1 Avoiding CO2 Emissions 461.5.2 Reducing CO2 Emissions 461.5.3 Desalination of Zero Liquid Discharge 46

1.6 Conclusions 471.7 The Software Programs Developed by the Author for System Analysis 47

1.7.1 Four Programs Developed and Their Entries 471.7.2 Major Ingredients of Each Program 491.7.3 The Software 49Appendix 501.A.1 Brief Description of the Thermodynamic Model of a System and

the Design Models of Its Main Components 501.A.1.1 Thermodynamic Model 501.A.1.2 Sample Design Models 50

1.A.2 The Capital and Fuel Costing Equations of some commonDevices (Tables 1.A.1 and 1.A.2) 54

1.A.3 Some Useful Forms of Flow Exergy Expressions 591.A.3.1 Equations 591.A.3.2 Balances 63

1.A.4 Theoretical Separation Work Extended to Zero LiquidDischarge 64

INTRODUCTION 3

Selected References for Section 1.1–1.3 72Further Reading 73

1.F.1 International Symposia on Energy Analysis 731.F.2 Selected International Symposia on Desalination 751.F.3 Books on Thermodynamics 751.F.4 Books on Optimization and Equation Solvers 751.F.5 Books on Design of Energy Conversion Devices 761.F.6 Books on Optimal Design 761.F.7 Books on Emerging Technologies (Fuel/Solar Cells and Selective

Membranes) 761.F.8 General Additional Reading for Section 1.2 761.F.9 General Additional Reading for Section 1.4 771.F.10 Literature on Design Models 78

1.1 INTRODUCTION

The topic of water desalination is revisited because of the negative impact of therising oil price index on the economic environment and the adverse effects ofthe increasing carbon footprint on the physical environment. In this introductorychapter, these negative factors are discussed with respect to their impact on pastand present desalination methods. The impact of these factors on the design andoperation practices of desalination and energy-intensive systems in general is high-lighted. The energy analysis methodologies developed during the last two decades,including the methodology discussed in the present study, are summarized. Generalreferences on the subject matter are listed in the Further Reading section at the endof this chapter.

The software mentioned in this chapter may be downloaded at http://booksupport.wiley.com.

1.1.1 Past and Present Desalination

Interest in water desalination began in the late 1950s and early 1960s when theprice of oil was only $3 per barrel (bl). A number of desalting processes andsystems were considered that sought to minimize the cost of water production. Forseawater, the leading methods were multistage flash distillation, vapor compressionand freezing. Other processes, such as electrodialysis and reverse osmosis, laggedsomewhat behind. Balancing the cost of the resources utilized in fueling a systemand the resources utilized in making its devices favored moderate efficiencydevices. For example, multistage flash distillation (MSF) in a cogeneration system

4 WATER DESALINATION REVISITED IN CHANGING PHYSICAL AND ECONOMIC ENVIRONMENTS

used a maximum temperature of around 190◦F (∼80◦C) in 8–12 stages. Costallocated to water was as low as $0.3/m3. Environmental constraints were virtuallyabsent.

As the oil price index increased to $25/bl, the number of the stages of conven-tional MSF increased to about 20 and the cost allocated to water rose to about$1/m3. At the same time, the awareness and concern regarding increased CO2emissions also increased.

Present desalination methods are facing a continuing increase in oil prices anda continuing increase of CO2 content in the air. This creates a serious concern todesigners and operators of desalination plants, power plants, and energy-intensiveplants in general. Innovative ideas, along with expanded R&D in certain directions,will be essential to boost prevailing technological advances to achieve higher-efficiency devices at lower cost.

Unfortunately, if the efficiencies of these devices are not high enough and theircosts are not low enough, then promoting conservation may be necessary in orderto reduce demand, followed by undesirable rationing.

1.1.2 The Emerged Concern

Early traditional approaches to the synthesis and design of energy-intensive systemsrelied on the intuition of experienced engineers and designers. Modest concern wasgiven to fuel consumption, and no concern was given to the environment or to wastemanagement.

The continuing rise in oil prices and the continuing increase in thecarbon footprint did, indeed, create a concern. Today the concern is at its peak,fueled by an increase in world population looking for a higher standard ofliving.

The concern regarding the environment did rise to a global level and did posea difficult challenge for the designers and operators of energy-intensive systems.Cost-effective fuel conservation became a focus of attention in the design and in theoperation of these systems. The design aspects became a complex multidisciplinaryprocess requiring specialized knowledge in each discipline. The operation aspectsbecame more responsive to any missmanagement of energy, emissions, and wastedisposal. Many research and development (R&D) projects emerged to target a newgeneration of energy systems to meet the challenge at both the producer end andthe consumer end.

There was an increased demand for improved methods of system analysis toachieve lower cost and higher efficiency, to facilitate the work of system designers.The methods of improved energy analysis influenced the design and the manufac-ture of energy conversion devices. Devices are now designed for the system asa whole rather than being selected from lines of preexisting components. Man-ufacture models are developed for the devices to reduce overall cost. The lowcost of “number crunching” has enhanced the development of energy-intensiveanalysis.

INTRODUCTION 5

Almost all methods developed involve optimization and seek innovation throughenergy-intensive analysis. Common tools are modeling and computational algo-rithms. However, the tendency for models to involve assumptions and view thesame system from different perspective has created variations in the quality andreliability of the developed models. It is, therefore, important that models be verifiedand also that both designers and operators be aware of the purpose of each modeland its limitations.

1.1.3 The Emerged Energy Analysis Methodologies

The interaction between cost and efficiency has always been recognized qualita-tively. However, the interest in formulating the interaction was first highlighted inconnection with seawater distillation in the 1960s to gain insight into the interac-tion between the surface of separation requirement and energy requirement. Thefirst landmark of the work on thermoeconomics [1] dealt with seawater desalinationprocesses. Further development followed in 1970 [2,3]. Professor Tribus coined theword thermoeconomics . Professor Gaggioli [4,5] generated interest in extending thedevelopment to all kinds of energy-intensive systems.

Since then the interest spread nationally and internationally by a large numberof investigators, and the development is still continuing. Various schools of thoughtregarding optimal system design have evolved in the last 30 years with the follow-ing common objectives:

• Increasing the ability to pinpoint and quantify energy inefficiencies.• Providing further insight into possible improvements in system design and

operation.• Automation of certain aspects of the search for improvement.

Investigators differ with respect to the techniques of managing system complexity.Four techniques may be identified, all of which allow changes in system structuredirectly or indirectly:

• Construct an internal system economy as a system decomposition strategy.Most of the work by these techniques falls under the heading of either ther-moeconomics or exergoeconomics [6–8].

• Consider a composite heat exchange profile of all heat exchange processesto identify where to add or reject heat and to produce and/or supply workappropriately. All work performed using this technique is termed “pinch tech-nology” [9].

• Let the computer automate the analysis by supplying it with a large database ofdevices and their characteristics. All the work performed using this techniqueis classified as expert systems or artificial intelligence [10].

• Consider evolutionary techniques based on the survival-of-the-fittest theory[11,12] to identify the desired system.

6 WATER DESALINATION REVISITED IN CHANGING PHYSICAL AND ECONOMIC ENVIRONMENTS

The author recommended the references listed in Sections 1.F.1–1.F.7 at the endof this chapter as useful readings for the preceding material.

1.2 THE METHODOLOGY USED IN THIS STUDY

The methodology discussed in this chapter, termed thermoeconomics , begins withsimple thermodynamic computations of a given system configuration on a trajec-tory leading to an optimal design via multidisciplinary computations involving thedisciplines of design, manufacture, and economics, in addition to thermodynamics.

In a typical thermodynamic model, the cost factor is absent. Decision variablesare mainly efficiency parameters of the processes involved, along with a few param-eters such as pressure, temperature, and composition. The computations target fuelconsumption, overall system efficiency, and duty parameters of the system devices.Evaluating cost involves input resources from the disciplines of design and man-ufacture in a prevailing economic environment. This, in turn, requires formulatedcommunications among the participating disciplines.

Thermoeconomic analysis targets minimized production costs and is based onthree main principles:

• Improved thermodynamic analysis, through the concept of exergy, to addtransparency to the distribution of lost work (exergy destructions) throughouta system configuration.

• Improved costing analysis, by quantifying the manufacturing and operatingcosts of the devices of a system, to add transparency to the interaction betweencost and efficiency.

• Enhanced optimization, via reasonable simplifying assumptions, to reachimproved design points for alternative and evolving system configurations.

1.2.1 Improved Thermodynamic Analysis

Improved thermodynamic analysis extends the conventional thermodynamic com-putations to include the second law of thermodynamics quantitatively rather thanqualitatively . The extended computations are simply entropy balance computa-tions in addition to property computations and the conventional mass, energy, andmomentum balances. Entropy is conserved in an ideal process and is created in areal process. The ideal adiabatic work of a compressor or a turbine (isentropic), forexample, is obtained when the entropy remains constant. Actual adiabatic work isassociated with entropy creation. The adiabatic efficiency relates the actual workto the ideal. The process inefficiency (irreversibility) measured as a lost workpotential = T0 S c, where T0 is an ultimate sink temperature.

The main advantage of extended computations is that they enable assignment offuel consumption to each process in a system. Fuel here means the input energyresource often applied at one location within the system boundaries. The energyresource may be fossil fuel, power, heat, solar, wind, or any other driving resource.

THE METHODOLOGY USED IN THIS STUDY 7

Thus, the manner in which a fuel is utilized throughout a system is revealed.Processes of high fuel consumption are identified. Means of fuel saving are inspiredby a structural change of the system or/and by a design point change. New avenuesof research and development are discovered.

It is important to note that engineers previously did not recognize the needto perform entropy balances. They could perform the thermodynamic analysisusing property computations, and efficiency-related variables of a process such aspressure or heat loss, adiabatic efficiency, and heat exchange effectiveness. Theymissed the advantage of the distribution of fuel consumption throughout a givensystem.

A more complete picture of efficiencies and inefficiencies is obtained by using ageneral potential work function known as exergy . For simple chemical systems, thisrepresents the maximum useful work relative to a dead-state environment definedby pressure P0, temperature T0, and composition {Xc0}. Exergy also representsthe minimum amount of work needed to create the system from the dead-stateenvironment.

1.2.1.1 The Exergy Function The exergy function is a general potentialwork function for simple chemical systems. The function evolved from the workof Carnot and Clausius, and is due to Gibbs [13]. The function is expressed asfollows:

E s = U + P0V − T0S −∑

μc0Nc (1.1)

Here, E s is the maximum work that could be obtained from a sample of matter ofenergy U , volume V , number of moles (or mass) of each matter species Nc whenthe sample of matter is allowed to come to equilibrium with an environment ofpressure P0, temperature T0, and chemical potential μc0 for each species Nc. Thesame expression measures the least work required to create such a sample of matterfrom same environment. A form useful to second-law computations for systems inthe steady state is

E f = H − T0S −∑

μc0Ni (1.2a)

where E f is flow exergy. For convenience, it is often expressed as the sum oftwo changes: (1) a change under constant composition {Xc} from the state atP and T to a state at a reference point between P0 and T0 and (2) a changeunder constant P0 and T0 from composition {Xc} to a state at reference {Xc0}. Thestate at P0 + T0 + {Xc0} defines the reference dead-state environment for computingexergy

E f = (H − H 0) − T0(S − S ◦) +∑

(μc − μc0)Nc (1.2b)

where (H 0 − T0S ◦) P0,T0,Xc

= (∑

μcNc) P0·T0is used.

8 WATER DESALINATION REVISITED IN CHANGING PHYSICAL AND ECONOMIC ENVIRONMENTS

All special forms of potential workfunctions such as Carnot work, Keenam’savailability, Helmholz free energy, and Gibbs free energy are obtainable from idealinteraction between a simple chemical system and large dead state environmentusing mass, energy and entropy balances as given by El-Sayed [14].

Section 1.A.3 (in the end-of-chapter Appendix) gives some useful forms of flowexergy in terms of measurable parameters and discusses the selection of the dead-state environment(s). Two or more dead-state environments may be used wheneverthere is no interest in their relative work potential. A known equilibrium chemicalreaction may be introduced to establish the equivalent equilibrium composition ofa missing species in a selected dead state environment.

1.2.2 Improved Costing Analysis

Most engineering activities seek the extreme of an objective function, which isusually a multicriterion function. Some criteria can be quantified in terms ofmonetary values such as fuel, equipment, and maintenance costs. Others involvenonunique assumptions regarding quantification of economic factors such as envi-ronmental impact, reliability, safety, and public health. In the design phase ofan energy system, however, concern peaks around two criteria— fuel and equip-ment —without violating other desired criteria. A closer look at the interactionbetween fuel and equipment (products of specified materials and shapes) nowfollows to establish an improved costing analysis along with the improved thermo-dynamic analysis—in other words, to establish a thermoeconomic analysis.

Even when the objective function focuses on fuel and equipment only as costs,the analysis becomes multidisciplinary in nature. At least four disciplines of knowl-edge participate in information exchange: thermodynamics, design, manufacture,and economics. A communication protocol has to be established among the partic-ipating disciplines to provide cost with a rational basis.

Unfortunately, bidding information and some engineering practices for estimat-ing the capital costs of major energy conversion devices are not helpful in theimprovement of system design. The estimations are often oversimplified by a dutyparameter for a group of devices such as a simple gas turbine unit costs of $500/kW.Such costs are not responsive to efficiency changes. The obvious way to recovermissed information is to communicate with designers and manufacturers or to applytheir practices encoded by suitable mathematical models.

1.2.2.1 The Quantification of the Manufacturing and OperationResources for a Device Any energy conversion device requires tworesources: those needed to manufacture it, Rmanuf, and those needed to operateit Roperate. These two resources increase with the device duty (capacity andpressure–temperature severity) and are in conflict with the device performingefficiency (one or more efficiency parameters). Since both resources are expensive,their minimum sum is sought.

1.2.2.1.1 The Manufacturing Resources The leading manufacturing activi-ties are materials, R&D, design, and construction. Exergy destruction associated

THE METHODOLOGY USED IN THIS STUDY 9

with the performed activities of these activities are difficult to trace back or evalu-ate. The capital cost of a device Z in monetary units is an indicator of the performedactivities, if not the best indicator. The capital cost, in turn, may be expressed byone or more characterizing parameters and their unit-dimensional costs:

Z = �cai Ai + k (1.3)

Usually one characterizing surface Ai of unit surface cost cai is an adequatequantification of Z . Ai is evaluated by an updated design model. The unit cost caiis a manufacturing cost evaluated by an updated manufacture model. The rate ofthe manufacturing resources then becomes

Rmanuf = Z = cz ca(Vmanuf)A(Vdesign) (1.4)

where Z is the capital cost rate and cz is the capital recovery rate.

1.2.2.1.2 Operating Resources The primary operation resources are related tofueling and other maintenance materials and activities. The fueling resource is whatthe device pulls or draws from the fueling supply point. In other words, it is simplythe exergy destruction performed by the device. Engineers, however, use efficiencyparameters (pressure loss ratio, adiabatic efficiency, effectiveness, etc.) to accountfor exergy destruction. All devices destroy exergy for their operation, dependingon their performance efficiency. Only ideal devices (operating at 100% efficiency),which do not exist, have zero exergy destruction when performing their duties. Therates of operating resources that do not go to the products are directly quantifiedby the rates of exergy destruction. In monetary units, the operating resources canbe expressed as

Roperate = cdD({Vduty}, {Vefficiency}) (1.5)

where D is the rate of exergy destruction of a device depending on its duty and effi-ciency and cd is the cost of its exergy destruction; cd depends on the cost of the fuelfeeding the system and on the position of the device within the system configuration.The objective function Ji of a device i to minimize at the device level is

Ji = Rmanuf + Roperate

= czi cai (Vmanufacture)Ai (Vdesign) + cdiDi ({Vduty}, {Vefficiency}) (1.6)

1.2.2.2 Correlating the Manufacturing Resources of a Device in Termsof Thermodynamic Variables Communication between the thermodynamicand the design models makes it possible to express Ai as a minimized surfaceAi min({Vduty}, {Vefficiency}), and communication between the design and themanufacture models allows one to express cai = Zmin(Vmanuf)/A(Vdesign) as aminimized unit surface price ca min({Vduty}, {Vefficiency}).

10 WATER DESALINATION REVISITED IN CHANGING PHYSICAL AND ECONOMIC ENVIRONMENTS

State-of-the-art or updated design and manufacture models are sought for majorsystem devices. A conventional thermodynamic model delivers to each deviceits respective {Vduty}, {Vefficiency} obtained from one feasible system solution. Thedesign model of the device minimizes the characterizing surface of the deviceby adjusting the design dimensions of the design model that represent its designdegrees of freedom. The minimized surface Amin is sent to the manufacture modelto minimize the manufacturing cost of the device design blueprint by adjustingthe decision variables of the manufacture model, which represent its manufactur-ing degrees of freedom. The minimized unit surface cost ca min is the minimizedmanufacturing cost/Amin.

This process is repeated over a range of feasible system solutions of interest tooptimal system design. A matrix of rows representing feasible system solutions asrelated to a device and of columns representing thermodynamic duty and efficiencyvariables, design decision variables, and manufacture decision variables allows themanufacturing cost of a device in terms of design and manufacturing variables tobe correlated in terms of thermodynamic variables.

A device objective function in terms of thermodynamic variables can beexpressed as

Ji = Rmanuf + Roperate

= cz cai min({Vduty}, {Vefficiency})Ai min({Vduty}, {Vefficiency})+ cdi Di ({Vduty}, {Vefficiency}) (1.7)

where caimn, Ai min, and Di are all functions of {Vduty} and {Vefficiency}, tending, ingeneral, to increase with duty, and are at conflict with efficiency.

Communication between the system thermodynamic model and the designmodels of its devices has been applied to a fair number of any conversiondevices as given in Section 1.A.1. An example of such communication forforced-convection heat exchangers, in which the manufacturing cost of a heatexchanger is expressed in terms of thermodynamic variables, is given in Section1.A.2.

However, the communication between design and manufacture is still lagging.The unit surface manufacture cost is derived, at the moment, from published costinformation rather than by manufacturing models. The communication betweendesign and manufacture models of devices is still being formulated.

1.2.3 Enhanced Optimization

1.2.3.1 Two Simplifying Assumptions The optimization of an energysystem configuration is most expedient when the system devices are optimizedone by one with respect to the decision variables of the system. Improvedthermodynamic and costing analyses have two basic features that qualify a systemfor device-by-device optimization:

• The assignment of fuel consumption to each device of the system establishesthe operating costs of the system devices.