DOCSLIB.ORG

Dynamic Modeling of Multi Stage Flash (MSF) Desalination Plant

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Dynamic Modeling of Multi Stage Flash (MSF) Desalination Plant Dynamic Modeling of Multi Stage Flash (MSF) Desalination Plant by Hala Faisal Al-Fulaij Department of Chemical Engineering University College London Supervisors: Professor David Bogle Thesis submitted for the degree of Doctor of Philosophy (Ph.D.) at University College London (UCL) July 2011 I, Hala Faisal Al-Fulaij, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. Hala F. Al-Fulaij Acknowledgments i Acknowledgments This Ph.D. was carried out between March 2007 and January 2011 at the Chemical Engineering department, University College London (UCL). This work was supervised by Professor David Bogle (UCL) and Professor Hisham Ettouney (Kuwait University). I take this opportunity to thank both of my supervisors for general guidance throughout the project and their great help, support and insight. I also thank Professor Giorgio Micale and Doctor Andrea Cipollina from University of Palermo who expended their time and made significant contribution to my knowledge especially in the computer tools field. Also, I am grateful for the love and support of my family, especially my mother, father, husband and sisters. Their patience and encouragement have given me the strength to complete my thesis study. Finally I would like to dedicate this thesis to my lovely children (Rayan, Maryam, AbdulWahab and Najat) hoping them the most of health, success, and happiness. Abstract ii Abstract The world population is increasing at a very rapid rate while the natural water resources remain constant. During the past decades industrial desalination (reverse osmosis (RO) and multistage flash desalination (MSF)) became a viable, economical, and sustainable source of fresh water throughout the world. In the MSF units, the flashing of seawater involves formation of pure vapour, which flows through a wire mesh demister to remove the entrained brine droplets and then condenses into product water. The study presented in this thesis is motivated by the absence of detailed modelling and analysis of the dynamics of the MSF process and the demister. A detailed dynamic model can be used in design, control, startup/shutdown and troubleshooting. Most of the previous studies on MSF plant focused on model development and presented limited amount of performance data without any validation against plant data. Literature models of the MSF demister are either empirical or semi-empirical. This motivated use of a computational fluid dynamics (CFD) software to design a new demister that will reduce the pressure/temperature drop in the vapour stream without affecting the separation efficiency of brine droplets and allows the optimal design of complete MSF units. Lumped parameter dynamic models were developed for the once through (MSF-OT) and the brine circulation (MSF-BC) processes. The models were coded using the gPROMS modelling program. The model predictions for both MSF-OT and MSF-BC in steady state and dynamic conditions showed good agreement against data from existing MSF plants with an error less than 1.5%. Dynamic analysis was made to study plant performance upon making step variations in system manipulated variables and identify stable operating regimes. New stable operating regimes were reached upon changing the cooling water flow rate by + 15% and increasing the recycle brine flow rate by 15% and decreasing it by 7%. This was not the case for the steam temperature where its variation was limited to + 2-3 %. This behavior is consistent with the actual plant data. The FLUENT software was used to model the MSF demister using different combinations of Eulerian and Lagrangian approaches to model the vapour and the Abstract iii brine droplets. This provided the open literature with novel and new methodologies for design and simulation of the MSF demister using CFD. A new demister design was made upon varying the wire diameter. This led to an efficient design with low pressure drop and high separation efficiency. This design was used in the MSF/gPROMS model to predict its effect on the heat transfer area. The new design provided reductions of 3-39% in the condenser heat transfer area without affecting dynamic performance. Since the tubing system accounts for almost 70% of the capital cost, then this would reduce the plant capital cost and product unit cost. The modelling approach presented in this thesis enables design of thermal desalination units to determine optimal heat transfer area and optimized operating conditions. Table of Contents iv Table of Contents Acknowledgments i Abstract ii List of Figures ix List of Tables xvii Chapter 1: Introduction and motivation 1 Chapter 2: Water Desalination 5 2.1 Introduction 5 2.2 Water Shortage Problem 5 2.3 Sources of Fresh Water 7 2.4 Types of water 9 2.5 Sea Water Composition and Properties 10 2.6 Need for Water Desalination 12 2.7 Classification of Desalination Technology 18 2.7.1 Thermal Processes 18 2.7.2 Membrane Processes 19 2.8 Multistage Flash Desalination 19 2.8.1 Once through MSF Process 21 2.8.2 Brine circulation MSF Process 23 2.8.3 Comparison between MSF Processes 28 2.8.4 Flashing stage description 30 2.9 Conclusion 34 Chapter 3: Modeling of MSF Processes: Literature Review 35 3.1 Introduction 35 3.2 Simple Mathematical Models 36 3.3 Detailed Mathematical Models 40 Table of Contents v 3.3.1 Steady State Models 40 3.3.2 Dynamic Models 44 3.4 Conclusion 51 Chapter 4: Dynamic Modeling of MSF Plant 53 4.1 Introduction 53 4.2 Model Basis and Assumptions 54 4.3 Model Structure 55 4.4 Once Through MSF Process (MSF-OT) 56 4.4.1 Mathematical equations 56 4.4.1.1 Lower Level Model (Flashing Stage Model) 57 4.4.1.2 Higher Level Model (MSF Plant) 65 4.5 Brine circulation MSF Process (MSF-BC) 69 4.5.1 Mathematical equations 69 4.5.1.1 Lower Level Model (Heat Gain Section Falshing Stage Model) 69 4.5.1.2 Lower Level Model (Heat Rejection Section Falshing Stage Model) 71 4.5.1.3 Higher Level Model 73 4.6 gPROMS Modeling Language 73 4.7 Conclusion 75 Chapter 5: Validation and Results of Dynamic Modeling of MSF Plants 77 5.1 Introduction 77 5.2 Modeling real MSF-OT Plants 77 5.2.1 Cases investigated, assignment and initial conditions 77 5.2.2 Model Validation Results 78 5.2.2.1 Steady state Validation Results 79 5.2.2.2 Dynamic Model Validation Results 81 5.2.3 Dynamic Response Results 85 5.3 Modeling Real MSF-BC Plants 90 Table of Contents vi 5.3.1 Cases investigated, assignment and initial conditions 90 5.3.2 Model Validation Results 92 5.3.2.1 Steady state Validation Results 93 5.3.2.2 Dynamic Model Validation Results 94 5.3.3 Dynamic Response Results 97 5.3.4 Effect of demister losses on heat transfer area of the condenser tubes 113 5.4 Conclusion 116 Chapter 6: CFD Modeling of the Demister 117 6.1 Introduction 117 6.2 Demisters Element Description 121 6.3 Modeling of Demisters : Literature Review 129 6.4 Mathematical Model Equations (Eulerian-Eulerian method) 132 6.4.1 Porous Media with Multi Phase Flow 133 6.4.2 Tube Banks with Multi Phase Flow 143 6.5 Mathematical Model Equations (Eulerian-Lagrangian method) 147 6.5.1 Tube Banks with Discrete Phase Model 147 6.6 Description of the CFD Code 151 6.7 Model Assumptions 153 6.7.1 Porous Media model 154 6.7.2 Tube Banks- Multi phase model 154 6.7.3 Tube Banks with discrete phase model 154 6.8 Solution Methods of CFD Codes 155 6.9 Conclusion 156 Chapter 7: Validation and Results of CFD Modeling of the Demister 158 7.1 Introduction 158 7.2 Porous Media – Multi Phase Model Approach: 158 Table of Contents vii 7.2.1 Grid sensitivity analysis 159 7.2.2 Cases investigated, geometries and boundary conditions 167 7.2.3 Model validation 169 7.2.4 Modeling results and discussion 175 7.3 Tube Banks –Multi Phase Model Approach 177 7.3.1 Grid sensitivity analysis 178 7.3.2 Cases investigated, geometries and boundary conditions 184 7.3.3 Model validation 185 7.4 Tube Banks –Discrete Phase Model Approach 191 7.4.1 Grid sensitivity analysis 191 7.4.2 Cases investigated, geometries and boundary conditions 196 7.4.3 Model validation 199 7.4.4 Comparison between performance of different demisters 207 7.5 Conclusion 209 Chapter 8: Improving MSF Plant Performance 211 8.1 Introduction 211 8.2 Effect of Improved Demister on the MSF-OT Plant 212 8.2.1 Effect of new demister on the product quality 212 8.2.2 Effect of new demister on the flashing stage condenser area 213 8.3 Effect of Improved Demister on the MSF-BC 217 8.3.1 Effect of new demister on the product quality 217 8.3.2 Effect of new demister on the flashing stage condenser area 218 8.3.3 Effect of new demister system dynamics 226 8.4 Conclusion 229 Table of Contents viii Chapter 9: Conclusions and Future work 230 9.1 Conclusions 230 9.2 Future work 233 Notation 237 Bibliography 242 Publications 254 Appendix A: Model Physical Properties Correlations 256 Appendix B: Degree of Freedon in gPROMS Models 263 Appendix C: (MSF-OT) gPROMS Code 267 Appendix D: (MSF-BC) gPROMS Code 286 List of Figures ix List of Figures Figure 2.1 Variation in world population from 1823 to 2050 6 Figure 2.2 Desalination market shares of large producers 13 Figure 2.3 MSF unit capacity growth 14 Figure 2.4 Market share of the main desalination process for desalination of river, brackish and seawater 15 Figure 2.5 Market share of the main desalination process for desalination of seawater 15 Figure 2.6 Cumulative production capacity of MSF plants in the Gulf countries 16 Figure 2.7 Conventional thermal and membrane desalination processes 18 Figure 2.8 View of a typical multistage flash desalination plant 23 Figure 2.9 Multistage flash desalination once through process (MSF- OT) 24 Figure 2.10 Multistage flash desalination with brine circulation (MSF- BC) 27 Figure 2.11 MSF flashing stage showing input and output variables 33 Figure 2.12 Two types of MSF orifices.
Load more

Recommended publications
  • Reverse Osmosis and Nanofiltration, Second Edition
    Reverse Osmosis and Nanofiltration AWWA MANUAL M46 Second Edition Science and Technology AWWA unites the entire water community by developing and distributing authoritative scientific and technological knowledge. Through its members, AWWA develops industry standards for products and processes that advance public health and safety. AWWA also provides quality improvement programs for water and wastewater utilities. Copyright © 2007 American Water Works Association. All Rights Reserved. Contents List of Figures, v List of Tables, ix Preface, xi Acknowledgments, xiii Chapter 1 Introduction . 1 Overview, 1 RO and NF Membrane Applications, 7 Membrane Materials and Configurations, 12 References, 18 Chapter 2 Process Design . 21 Source Water Supply, 21 Pretreatment, 26 Membrane Process Theory, 45 Rating RO and NF Elements, 51 Posttreatment, 59 References, 60 Chapter 3 Facility Design and Construction . 63 Raw Water Intake Facilities, 63 Discharge, 77 Suspended Solids and Silt Removal Facilities, 80 RO and NF Systems, 92 Hydraulic Turbochargers, 95 Posttreatment Systems, 101 Ancillary Equipment and Facilities, 107 Instrumentation and Control Systems, 110 Waste Stream Management Facilities, 116 Other Concentrate Management Alternatives, 135 Disposal Alternatives for Waste Pretreatment Filter Backwash Water, 138 General Treatment Plant Design Fundamentals, 139 Plant Site Location and Layout, 139 General Plant Layout Considerations, 139 Membrane System Layout Considerations, 140 Facility Construction and Equipment Installation, 144 General Guidelines for Equipment Installation, 144 Treatment Costs, 151 References, 162 iii Copyright © 2007 American Water Works Association. All Rights Reserved. Chapter 4 Operations and Maintenance . 165 Introduction, 165 Process Monitoring, 168 Biological Monitoring, 182 Chemical Cleaning, 183 Mechanical Integrity, 186 Instrumentation Calibration, 188 Safety, 190 Appendix A SI Equivalent Units Conversion Tables .
    [Show full text]
  • Characterization and Performance of Nanofiltration Membranes
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Covenant University Repository Environ Chem Lett (2014) 12:241–255 DOI 10.1007/s10311-014-0457-3 REVIEW Characterization and performance of nanofiltration membranes Oluranti Agboola • Jannie Maree • Richard Mbaya Received: 16 October 2013 / Accepted: 17 January 2014 / Published online: 1 February 2014 Ó Springer International Publishing Switzerland 2014 Abstract The availability of clean water has become a nanofiltration membranes. We also present a new concept critical problems facing the society due to pollution by for membrane characterization by quantitative analysis of human activities. Most regions in the world have high phase images to elucidate the macro-molecular packing at demands for clean water. Supplies for freshwater are under the membrane surface. pressure. Water reuse is a potential solution for clean water scarcity. A pressure-driven membrane process such as Keywords Nanofiltration membranes Á Membrane nanofiltration has become the main component of advanced characterizations Á Pore size Á Surface morphology Á water reuse and desalination systems. High rejection and Performance evaluation Á ImageJ software water permeability of solutes are the major characteristics that make nanofiltration membranes economically feasible for water purification. Recent advances include the pre- Introduction diction of membrane performances under different oper- ating conditions. Here, we review the characterization of Nanofiltration process is one of the most important recent nanofiltration membranes by methods such as scanning developments in the process industries. It shows performance electron microscopy, thermal gravimetric analysis, attenu- characteristics, which fall in between that of ultrafiltration ated total reflection Fourier transform infrared spectros- and reverse osmosis membranes (Mohammed and Takriff copy, and atomic force microscopy.
    [Show full text]
  • Nanofiltration (NF) Is a Pressure Driven Membrane Process
    Nanofiltration Nanofiltration (NF) is a pressure driven membrane process. Hydraulic pressure is used to overcome the feed solution’s osmotic pressure and to induce diffusion of pure water (referred to as permeate) through a semi-permeable NF membrane. The residual feed stream (referred to as retentate, concentrate, or reject) is concentrated by the process, and depending on water quality, may be suitable for further water recovery in additional downstream unit processes; otherwise, the residual stream requires disposal. NF is designed to achieve high removal of divalent and multivalent ions (e.g., calcium, magnesium, sulfate, iron, arsenic, etc.), and is occasionally referred to as membrane softening. NF may achieve moderate to low removal of monovalent ions (e.g., sodium, potassium, chloride). NF is commonly employed to remove hardness from brackish groundwater to produce potable water. Water characterized by high concentrations of calcium or magnesium and monovalent salts may be treated with NF prior to a reverse osmosis. An illustration of the process is shown below. FEED NF PERMEATE CONCENTRATE Summary of technical assessment of NF Criteria Description/Rationale Status of technology Mature and robust technology for water softening and metals removal in various sectors of the industrial and municipal water treatment sectors. Has been employed for produced water treatment. Feed water quality bins Feed water total dissolved solids concentration applicability depends on feed solution composition and may range from 500 to 12,000 mg/L. Most useful for treatment of water with high concentrations of divalent ions (e.g., magnesium, calcium, barium, sulfate), multivalent metals ions (e.g., iron, manganese), and radionuclides.
    [Show full text]
  • Forward Osmosis – a Brief Introduction
    Forward Osmosis – A Brief Introduction This paper outlines some of the aspects of Forward Osmosis process and its derivatives, with regard to key issues, concepts and some applications. By Peter G. Nicoll Forward Osmosis (FO) over the past five years has generally it is apparent that they are increasingly becoming a topic of some attracted more attention, both academically and commercially, interest. National Geographic [1] in an article in April 2010 cited it with a number of companies raising finance on the back of its as one of the three most promising new desalination technologies potential. The process exploits the natural process of osmosis, and at the last IDA World Congress in Perth, Australia in 2011, which is how plants and trees take up water from the soil – a low six papers were published on this subject. In the Journal of energy, natural process. It works by having two solutions with Membrane Science the number of papers published has seen a different concentrations (or more correctly different osmotic very significant increase over the last three years (24 in 2012), pressures) separated by a selectively permeable membrane, in the showing the increasing level of academic interest. We have also case of the plants and trees their cell walls, and ‘pure’ water flows seen the emergence of a number of commercial organisations from less concentrated solution across the membrane to dilute with significant funding to develop and exploit the technology the more concentrated solution, leaving the salts behind. The clue such as, Hydration Technology Innovations Inc, Modern Water in the potential applications is that it is widely used in nature, plc, Oasys Water Inc, Statkraft AS and Trevi Systems Inc.
    [Show full text]
  • Journal of Membrane Science 593 (2020) 117444
    Journal of Membrane Science 593 (2020) 117444 Contents lists available at ScienceDirect Journal of Membrane Science journal homepage: www.elsevier.com/locate/memsci Nanofiltration membranes with hydrophobic microfiltration substrates for robust structure stability and high water permeation flux T ∗∗ ∗ Xi Zhanga,b, Chang Liua,b, Jing Yanga,b, , Cheng-Ye Zhua,b, Lin Zhangc, Zhi-Kang Xua,b, a MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Hangzhou, 310027, China b Key Laboratory of Adsorption and Separation Materials & Technologies of Zhejiang Province, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou, 310027, China c Key Laboratory of Biomass Chemical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China ARTICLE INFO ABSTRACT Keywords: Traditional nanofiltration membranes (NFMs) suffer from ultrafiltration substrates with low porosity, small pore Nanofiltration membrane size and relatively poor solvent stability. Herein, NFMs have been fabricated on a series of hydrophobic polymer Microfiltration substrate microfiltration substrates to address these issues. Polyphenol-based coatings of tannic acid/diethylenetriamine Surface wettability (TA/DETA) were co-deposited on the hydrophobic substrates to improve their surface wettability and to make Water permeation flux them appropriate for interfacial polymerization. The spreading behaviors of aqueous solutions, which are of Structure stability significant importance to the formation of defect-free polyamide layers, were directly visualized by laser con- focal microscopy. The influences of TA/DETA coatings on the interfacial polymerization were further demon- strated by both dynamic molecular simulation and nanofiltration performance evaluation. The as-prepared NFMs exhibit higher water permeation flux compared with traditional ones because of the large pore size and high porosity of the microfiltration substrates, as well as the relatively low cross-linking degree of polyamide layers.
    [Show full text]
  • 1 Selectrodialysis and Bipolar Membrane
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UPCommons. Portal del coneixement obert de la UPC 1 SELECTRODIALYSIS AND BIPOLAR MEMBRANE ELECTRODIALYSIS 2 COMBINATION FOR INDUSTRIAL PROCESS BRINES TREATMENT: 3 MONOVALENT-DIVALENT IONS SEPARATION AND ACID AND BASE 4 PRODUCTION 5 6 Mònica Reig1,*, César Valderrama1, Oriol Gibert1,2, José Luis Cortina1,2 7 8 1Chemical Engineering Dept., UPC-Barcelona TECH, Av. Diagonal 647, 08028 Barcelona, Spain 9 2CETAQUA Carretera d'Esplugues, 75, 08940 Cornellà de Llobregat, Spain 10 *Corresponding author: Tel.:+34 93 4016997; E-mail address: [email protected] 11 12 13 ABSTRACT 14 Chemical industries generate large amounts of wastewater rich in different chemical 15 constituents. Amongst these, salts at high concentrations are of major concern, making 16 necessary the treatment of saline effluents before discharge. Because most of these rejected 17 streams comprise a combination of more than one salt at high concentration, it is reasonable 18 to try to separate and revalorize them to promote circular economy at industry site level. For 19 this reason, ion-exchange membranes based technologies were integrated in this study: 20 selectrodialysis (SED) and electrodialysis with bipolar membranes (EDBM). Different 21 process brines composed by Na2SO4 and NaCl at different concentrations were treated first by 22 SED to separate each salt, and then by EDBM to produce base (NaOH) and acids (HCl and 23 H2SO4) from each salt. The optimum of both electrolyte nature and concentration of the SED - 2- 24 stack streams was evaluated. Results indicated that it was possible to separate Cl and SO4 25 depending on the anionic membrane, initial electrolytes and concentrations of each stream.
    [Show full text]
  • Membrane Filtration
    Membrane Filtration A membrane is a thin layer of semi-permeable material that separates substances when a driving force is applied across the membrane. Membrane processes are increasingly used for removal of bacteria, microorganisms, particulates, and natural organic material, which can impart color, tastes, and odors to water and react with disinfectants to form disinfection byproducts. As advancements are made in membrane production and module design, capital and operating costs continue to decline. The membrane processes discussed here are microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO). MICROFILTRATION Microfiltration is loosely defined as a membrane separation process using membranes with a pore size of approximately 0.03 to 10 micronas (1 micron = 0.0001 millimeter), a molecular weight cut-off (MWCO) of greater than 1000,000 daltons and a relatively low feed water operating pressure of approximately 100 to 400 kPa (15 to 60psi) Materials removed by MF include sand, silt, clays, Giardia lamblia and Crypotosporidium cysts, algae, and some bacterial species. MF is not an absolute barrier to viruses. However, when used in combination with disinfection, MF appears to control these microorganisms in water. There is a growing emphasis on limiting the concentrations and number of chemicals that are applied during water treatment. By physically removing the pathogens, membrane filtration can significantly reduce chemical addition, such as chlorination. Another application for the technology is for removal of natural synthetic organic matter to reduce fouling potential. In its normal operation, MF removes little or no organic matter; however, when pretreatment is applied, increased removal of organic material can occur.
    [Show full text]
  • Applications of Nanotechnology in Membrane Distillation: a Review Study
    Desalination and Water Treatment 192 (2020) 61–77 www.deswater.com July doi: 10.5004/dwt.2020.25821 Applications of nanotechnology in membrane distillation: a review study Mamdouh El Haj Assada,*, Ehab Bani-Hanib, Israa Al-Sawaftaa, Salah Issaa, Abir Hmidac, Madhu Guptad, Rahman S.M. Atiqurea, Khaoula Hidouric aSustainable and Renewable Energy Engineering Department, University of Sharjah, P.O. Box: 27272, Sharjah, UAE, emails: [email protected] (M. El Haj Assad), [email protected] (I. Al-Sawafta), [email protected] (S. Issa), [email protected] (R.S.M. Atiqure) bSchool of Engineering, Australian College of Kuwait, Mishref, Kuwait, email: [email protected] (E. Bani-Hani) cNational Engineering School of Gabès, Applied Thermodynamics Research Laboratory, University of Gabès, Omar Ibn El Khattab Street, Gabès, 6029, Tunisia, emails: [email protected] (A. Hmida), [email protected] (K. Hidouri) dSchool of M.M.H. College, Ghaziabad, U.P. Resi-# 7/48 Sector-2, Rajendra Nagar, Sahibabad, Ghaziabad – 201005, India, email: [email protected] (M. Gupta) Received 27 June 2019; Accepted 10 March 2020 abstract Membrane distillation (MD) is an effective water treatment process with relatively low cost compared to conventional membrane processes. This study investigates several factors affecting the performance of the MD membrane such as fouling, porosity, pore size, mechanical stability, contact angle, salt rejection, and other physical and thermal properties. Membrane performance can be improved if membranes are manufactured using nanotechnology. This work presents a review of the application of recently discovered nanotechnology that improves the properties and enhances the performance of membranes used in water distillation processes.
    [Show full text]
  • An Attempt to Optimise the Process of Nanofiltration of Pool Water Enriched with Compounds Associated with Secretions of the Human Body †
    Proceedings An Attempt to Optimise the Process of Nanofiltration of Pool Water Enriched with Compounds Associated with Secretions of the Human Body † Edyta Łaskawiec *, Mariusz Dudziak and Joanna Wyczarska-Kokot Institute of Water and Wastewater Engineering, Faculty of Energy and Environmental Engineering, Silesian University of Technology, Konarskiego 18, 44–100 Gliwice, Poland; [email protected] (M.D.); [email protected] (J.W.-K.) * Correspondence: [email protected]; Tel.: +48-32-237-16-98 † Presented at Innovations-Sustainability-Modernity-Openness Conference (ISMO’19), Bialystok, Poland, 22–23 May 2019. Published: 14 June 2019 Abstract: This paper discusses the possibilities of purifying pool water by the process of nanofiltration. The analysis was carried out in the presence of substances analogous to the secretions of the human body. The samples of water collected from the school swimming pool was enriched with selected organic and inorganic compounds. The transport-separation properties of nanofiltration membranes were assessed. In the context of the removal of these organic compounds, the measurement of the total organic carbon concentration was of particular importance. Keywords: swimming pool water; body fluids analogues; pressure driven membrane processes 1. Introduction It is estimated that during one hour of physical activity one swimmer may excrete 50 mL of urine and 200 ml of sweat, which results in the release into the water of many organic compounds whose structures comprise nitrogen, which quickly reacts with chlorine-based disinfectants [1]. The concentration and composition of disinfection by-product (DBP) precursors classified as body fluid analogues (BFAs) are strongly correlated with the number of swimmers, their hygiene habits, and the intended use of the pool.
    [Show full text]
  • Modeling the Capital and Operating Costs of Thermal Desalination
    Desalination and Water Purification Research and Development Program Report No. 130 WT Cost II Modeling the Capital and Operating Costs of Thermal Desalination Processes Utilizing a Recently Developed Computer Program that Evaluates Membrane Desalting, Electrodialysis, and Ion Exchange Plants U.S. Department of the Interior Bureau of Reclamation February 2008 REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. T T T T T 1.T REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) February 2008 Final Final 4.T TITLE AND SUBTITLE 5a. CONTRACT NUMBER WT Cost II Agreement No. 04-FC-81-1038 Modeling the Capital and Operating Costs of Thermal Desalination Processes 5b. GRANT NUMBER Utilizing a Recently Developed Computer Program that Evaluates Membrane Desalting, Electrodialysis, and Ion Exchange Plants 5c.
    [Show full text]
  • Introduction to Desalination Technologies
    Introduction to Desalination Technologies Hari J. Krishna1 Definition and brief history Desalination can be defined as any process that removes salts from water. Desalination processes may be used in municipal, industrial, or commercial applications. With improvements in technology, desalination processes are becoming cost-competitive with other methods of producing usable water for our growing needs. During World War II, it was felt that desalination technology - ‘desalting’ as it was called then - should be developed to convert saline water into usable water, where fresh water supplies were limited. Subsequently, “The Saline Water Act” was passed by Congress in 1952 to provide federal support for desalination. The U.S. Department of the Interior, through the Office of Saline Water (OSW) provided funding during the 1950s and 60s for initial development of desalination technology, and for construction of demonstration plants. Desalination is a relatively new science that has developed to a large extent during the latter half of the 20th century, and continues to undergo technological improvements even at the present time. It is interesting to note that one of the first seawater desalination demonstration plants to be built in the United States was at Freeport, Texas in 1961. Dow, in cooperation with the U.S. Department of the Interior built a 1 million gallons per day (mgd) long tube vertical distillation (LTV) plant at a cost of $1.2 million, that produced water for the City of Freeport and for Dow operations. The plant was officially opened on June 21, 1961 by then President John F. Kennedy, by pressing a button from the White House.
    [Show full text]
  • Nanofiltration and Reverse Osmosis Nanofiltration and Reverse Osmosis Contents
    CT4471 Drinking water I Dr.ir. S.G.J. Heijman nanofiltration and reverse osmosis Nanofiltration and reverse osmosis Contents 1. Introduction 2. Theory 3. Membrane modules 4. Applications 5. Design 6. Fouling control Introduction Size, µm 0.001 0.01 0.1 1.0 10 100 1000 Approximate molecular 100 200 1000 10000 20000 100000 500000 weight Viruses Bacteria Relative size of Dissolved salts Algae materials in water Metal ions Humus acids Cystes Sand Clay Silt ΔP [bar] Conventional filtration processes 0.01 Micro filtration 0.05 Treatment Ultra filtration 0.1 process Nanofiltration 5 Reverse osmosis 30 ED and EDR Metal ions Dissolved salts Viruses Bacteria Cryptosporidium Arsenic Calcium salts Contagious Giardia Salmonella Nitrate Sulfate salts Hepatitis Nitrite Magnesium salts Shigellosis Protozoa Cyanide Aluminum salts Vibrio cholera Cystes Introduction •Bacteria •Virusses •Multivalent •Monovalent salts salts Microfiltration MF + - - - Ultrafiltration + + - - UF Nanofiltration + + + - NF Reversed Osmosis + + + + RO October 16, 2007 4 Introduction Introduction • Spiral wound membrane Modules • Spiral wound membranes Introduction • Principle slow sand filtration v = 0.10 m/h d = 0.15 – 0.35 mm October 16, 2007 8 Introduction • Slow sand filtration slow sand filtration October 16, 2007 9 Introduction • Parallel MF/SSF Problems: 1. Fouling 2. Packing flux = 0.01 m/h October 16, 2007 10 Introduction • Traditional RO/NF - fouling spacers Concentrate channel Permeate channel October 16, 2007 11 Turbulent flow across membranes Introduction • Filtration process and particle size Particle size pressure MWCO flux [nm] [bar] [m3/m2·h] Micro filtration > 100 < 1 0.04 - 0.2 Ultra filtration 10 - 100 < 2 1000 - 10000 0.08 - 0.2 Nano filtration 1 - 2 5 - 10 200 - 500 0.02 - 0.08 Reverse osmosis0.2 - 1 15 - 60 100 0.01 - 0.04 MWCO = Molecular Weight Cut Off = 90% of organic molecules is removed Contents 1.
    [Show full text]