11 March 2008 New Advancement of Seawater Desalination Reverse Osmosis Membranes (SWRO) Dr. Masaru Kurihara Toray I ndustries, I nc.
Contents 1. Trends on Seawater RO Desalination 2. Scientific Research on Boron Removal Mechanism by RO Membrane 3. Recent Advancement of High Boron Rejection SWRO Membrane 4. Conclusion 2
1. Trends on Seawater RO Desalination 3
The Global Environmental Issues The “Carbon Dioxide Issue” and the “Water Issue” ！ Issues of Shortage and Pollution CO 2 Emissions of Water Environments Acid Rain Acid Rain Desertification Desertification Tropical Forest Tropical Forest Global Warming Global Warming Depletion Depletion Marine Pollution Marine Pollution Pollution Pollution Ozone Layer Ozone Layer Waste Products Waste Products Depletion Depletion 4
World Water Resources and Water Issues R e l a t i o n s h i p b e t w e e n W a t e r , A n n u a l P e r C a p i t a W a t e r R e s o u r c e s E n e r g y a n d F o o d Water Electric Power Generation Desalination Virtual Water Agriculture [k liter / year, person] People in the World Bio-fuel Energy Food No data Area of very serious water shortage Source: FAO FAO: Food and Agriculture Organization Food Production [100 billion liters] I n c r e a s i n g G l o b a l W a t e r C o n s u m p t i o n T h e W a t e r I s s u e i s a G l o b a l C h a l l e n g e 6 0 5 2 . 4 (Estimate) � UN Target: “Halve the proportion of people without 3 9 . 7 � UN Target: “Halve the proportion of people without 4 0 access to drinking water or sanitation facilities“ - Not yet access to drinking water or sanitation facilities“ - Not yet achieved. achieved. � The water issue is a global challenge required to be � The water issue is a global challenge required to be 2 0 1 3 . 8 resolved together with the food and energy issues. resolved together with the food and energy issues. 5 . 8 � The water issue is a global challenge that should be � The water issue is a global challenge that should be dealt with on the same basis as the carbon dioxide issue. dealt with on the same basis as the carbon dioxide issue. 0 1 9 0 0 1 9 5 0 2 0 0 0 2 0 2 5 Source: Reference: Council for Science and Technology Policy, 67th Meeting (held on May 18, 2007) UNESCO Material 3: Recent Trends of Science and Technology “Japanese Technologies Contributing 5 to the World – An Example of Japanese Water Treatment Technologies － ”1
Increase of World Population and Development of Water Treatment Technologies World population Population (Billion) Revolution Industrial ⑤ Membrane 10.0 treatment ④ Evaporation 8.0 ③ Rapid filtration 6.0 ② Microorganism treatment 4.0 ① Slow filtration Natural purification 2.0 0 1700 1800 1900 2000 2100 【 Toray Estimate 】 Difficult to secure volume and quality of water only by natural purification due to the increase of rapid increase of population Membrane treatment technology, which enable control of high precise Membrane treatment technology, which enable control of high precise water quality and high speed treatment, is essential in 21 century water quality and high speed treatment, is essential in 21 century Reference: Tambo, N. et. ; "Infrastructure Development under Decreasing Population" - A Design from Expansion to Shrink -. 6 Japan Society of Civil Engineers. 2002, p.10. (Japanese)
Trend of Cumulative Capacities of Water Production Facilities by Technology 18,000,000 16,000,000 14,000,000 MED 12,000,000 MSF NF 10,000,000 RO 8,000,000 6,000,000 1990 1991 1992 4,000,000 1993 1994 1995 1996 1997 2,000,000 1998 1999 2000 2001 0 2002 2003 R O 2004 N F M 2005 S Authority: IDA Inventory no19 F M 2006 E D 7
Types of Membranes and Toray’s Membrane Products 0.001 ㎛ 0.01 ㎛ 0.1 ㎛ 1 ㎛ 10 ㎛ Size High molecular Ion, Low molecule Colloid weight organics weight polymer Separation materials Clay Trihalomethane Agricultural & Organic Material Virus Coliform Cryptosporidium Bacteria Monovalent Ions Multivalent Ions Types UF (Ultrafiltration ） RO (Reverse Osmosis ） MF (Microfiltration) NF (Nanofiltration) Ultrapure Water, Sewage Water Softening, Municipal Drinking Water, Toray’s membrane products Seawater Desalination, Treatment Removal of Toxic Reuse of Wastewater, Advanced Water substance Pretreatment for RO Process Treatment HF membrane MF membrane RO membrane NF membrane PVDF Immersed (PVDF Hollow (PVDF Hollow Fiber) membrane for MBR Fiber) 8
Technical Trends of RO Membranes Super low Operating Ultra low Low High Ultra high Notes Pressure 0.3 0.5 1.0 2.0 5.5 10.0 [MPa] Recovery = 60 ％ 2nd stg. High TDS removal SWRO High boron removal High Recovery 1st stg. High TDS removal Recovery = 40% Energy- High boron removal Saving Cost reduction BW RO Low-fouling Lower pressure High TOC removal water Ultra pure High quality Cost reduction Waste water reuse Low-fouling Cost reduction Energy saving membrane with retaining conventional performance will be expected. 9
５ ． 東レグループ水処理事業の現状と 拡大戦略 Technical Trends on SWRO Membrane Two technical requirements for SWRO membrane I. Energy saving Requirement for further improvement 15 Energy (kWh/m 3 ) 12.0 (Without boron regulation) 10 8.1 ADC 5.0 · High flux membrane at low 3.7 2.1 5 operating pressure - 2.3 1.6 · More effective energy recovery 0 device 1970 1980 1990 2000 2006 2007 Period II. Changes in the required water quality 1) At the time of initial stage in SWRO SWRO = Salt rejection was the most important factor. 2) In current years WHO actions against the boron regulation (in addition to item 1)) - The boron regulation guideline value in drinking water (1998). - The report for toxicity of boron in drinking water (2003). - New boron regulation guideline will be discussed in the IDA congress (2007). 10
Changes in Boron Regulation Recent trends of boron regulation and requirement. 1990 1993 1996 19971998 2000 2001 2005 2007 0.5mg/L 0.5mg/L Boron regulation WHO 0.3mg/l (guidline) (Pub.Com.) × 1,000m 3 /d 1.0 0.5 Spain 42 Not required mg/L mg/L Trinidad 136 Not required 0.3 World Israel 272 0.4mg/L mg/L 136 1.0mg/L Singapore 227 1.0mg/L Abu Dhabi 1.5mg/L California Okinawa 40 Not required Japan Fukuoka 50 1.5mg/L Boron regulation has been getting tougher especially after 2000. 11
Flow Diagram of SWRO Desalination Plant with Boron Regulation & without Boron Regulation Zone I : Single stage SWRO with boron regulation (ex. : Las Palmas III, Barcelona, Malta) (A) SWRO membrane (High boron rejection) Seawater Product water Zone I I : 2 to 4 stages SWRO with boron regulation (ex. : Ashkelon, Tuas , Shuaiba III ) (B) SWRO (High boron rejection, High water productivity) Seawater Product water (C) BWRO (High boron rejection, Alkaline dosing, High pH High productivity, Alkaline (pH10) tolerance Zone I I I : Single stage SWRO without boron regulation (ex. : Point Lisa, Al-Jubail, Okinawa) (D) SWRO (High water productivity, Low energy type) Membrane Manufacturers are competing with each other in these A - D types, respectively. 12
History and Prospect of Boron Rejection Performance 99 Boron rejection performance (%) “Renovative” “Improved” 95 “Conventional” “Early” 90 80 Toray 50 Others 0 -2000 2000-2003 2003-2007 2008- Period Toray has been investigating SWRO membranes with focusing on boron rejection. 13
2. Scientific Research on Boron Removal Mechanism by RO Membrane 1) Positron Annihilation Lifetime Spectroscopy 2) Solid-state 13 C NMR Spectroscopy 3) Molecular Dynamics Simulations 14
Purpose Conventional RO membrane structural analyses Imaginative Separating functional layer chemical structure Structure of Cross-linked aromatic H RO membrane N O polyamide, 0.2µm CO 2 H H H H H Support layer N N N N Membrane Poly sulfone, O O O O Surface 60µm NH How large is Substrate Insoluble to any solvent the pore? Non-woven fabric substrate, 150µm Poor information Predicted pore size distributions by removable substances 10Å 100Å Purpose in this work: Small Large Mol. 1. To establish a certain pore size Substances Mol. Colloid analysis method Bacteria Ion Organic Chemicals 2. To acquire some basic Virus physicochemical information for RO Predictions NF MD simulations UF roughly 5Å roughly 50Å 15
Candidate Membranes for Analyses The SWRO membranes with different boron removal rate were prepared, even though SWRO membranes had same NaCl rejection and water flux. Boron removal performance of SWROs 100 98 Boron removal rate (%) 96 S4 (95%) 94 S3 (94%) 92 S2 (92%) 90 S1 (90%) 88 0.0 0.2 0.4 0.6 0.8 1.0 Flux (m 3 /m 2 /day) Test condition: feed solution; TDS 35000 mg/l, temperature; 25 degree C., pH; 6.5, operating pressure; 800 psig (5.5 MPa), flow rate; 3.5 L/min. 16
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