OVERVIEW AND ROADMAP FOR MEMBRANE PROCESS DEVELOPMENT IN DESALINATION. Tony Fane

Transcription

1 DesalTech 2015, San Diego, Aug 28-29,2015 OVERVIEW AND ROADMAP FOR MEMBRANE PROCESS DEVELOPMENT IN DESALINATION Tony Fane Singapore Membrane Technology Centre Member of NEWRI Ecosystem

2 Outline Context Status Research Developments Roadmap and the Future Conclusions 2

3 Context Global Water Stress 2030 Source CSIRO Predicted trend is hotter and drier Climate change and economic growth 3

4 Singapore and Water Reclamation (NeWater) > SWRO Water 274ML/d Desalination 455 NeWater 500 * Wastewater MBR 23 MBR 2x60 to NeWater (i) GE Zenon end 2014 (ii) 2016 * 2060 Targets 6 th NEWater Desal = 30%, NeWater > 50% 4

5 Membranes and the Water Domain Fane, Wang, Hu, Status & Future of Membranes for Water, Angew. Chemie Intl, 54 (2015), 3368 WATER INPUT Nonsaline UF/MF etc Saline Sea/brackish UF/NF/FO SWRO [ED] [MD] Used water CASP/UF MBR RO Q H POWER Power Gen Biogas nonsal brine PRO RED saline nonsaline PRO RED WATER OUTPUT Potable & Industry Potable & Industry [Potable] Industry brine MD Cryst solids

6 Low Pressure Membranes Mainly hollow fibre polymeric Drinking Water (60%) + Pretreatment MBRs etc 2006 ~ 14,000 MLD 2013/14 > 35,0000 MLD 12% growth (G.Pearce) Submerged (Suction) D Furakawa, 2008, NWRI Trend to Contained? (Pressurized) Water Reclamation. All use LP membrane pretreatment. Seawater Desalination plant. - Trend is to LP membrane pretreatment. - Magtaa (Hyflux) 500 Mld desal = 1000 Mld Pretreatment 6

7 Low Pressure Membranes Application Share by Market Value as a Function of Time Period for Membrane Filtration in Water & Wastewater Pretreatment Greame Pearce : The Pearce Report; Low Pressure Membranes (in Prep) 7 IDA Conf: Session S-18, Tues pm Room E

8 Sea water RO: Plants & Modules Getting Larger RO growth is 10 to 15% 16 inch modules Vertically aligned M.Kurihara (Toray) Sorek, Israel, 624 MLD (2013) largest SWRO plant. 8

9 RO Plant Getting Larger Mega Ton Water Project (Japan) Sorek, 624 MLD Magtaa, 500 MLD M.Kurihara (Toray)

10 Outline Context Status Research Developments - Novel RO Desalination Membranes - Electrodialysis - Membrane Distillation - Forward Osmosis - Bioreactors Roadmap and the Future Conclusions 10

11 The Quest for Ultra permeable (UPM) RO membranes Revolutionary Graphene Evolutionary Evolutionary & Now Hollow Fibres AqP 100% FS R.Wang et al., JMS 494 (2015) 68- Far Now R.Wang et al., Recent data-submitted Flat Sheet AqP 50% Pendergast & Hoek, Energy & Env.Sci. (2011), 4, AqP Asia Y Zhao et al., JMS, 423 ( 2012) 11

12 Publications CNT desalination Web of Sci., Aug, 2015 Title Topic Publications Graphene desalination Web of Sci., Aug, 2015 Title Topic 12

13 Press Release March 25, 2015 Sumedh.S.et al, Water desalination using nanoporous single-layer graphene Nature Nanotechnology, 10, (May 2015), FO Mode data: A value = 70 g m -2 s -1 atm -1 = 250 LMH per bar (> 20 xcurrent) 13 Support is SiN microchip, A m = 5 micron.

14 Evolution of RO Permeability Advances in material science UPM potential Carbon NT, Graphene Aquaporin? Fane,Wang,Hu, Angew Chemie Intl, 54 (2015), 3368 Can we anticipate a step change in RO permeability? Could we use a step change in RO Permeability? 14

15 Electro dialysis Publications Electrodialysis desalination Web of Sci., Aug, 2015 Title Topic EDR desalination brackish river water (200 MLd) Desal 253 (2010)

16 Singapore s Desal Challenge (2008) 1.5 kwh/ m 3 Sea water feed Process X? Evoqua (Siemens WT) WHO standard DW 100mm filter UF ED + CEDI Post treat

17 Membrane Distillation - Long gestation but interest continues Publications MD in title Web of Sci., June, 2015 = 1370 ~600 in last 4 yrs ZLD MD crystallization FO draw regeneration Novel bioreactors Low GHG option 17

18 Flux (Kgm -2 hr -1 ) Flux (Kgm -2 hr -1 ) a 1 b Novel MD Membranes (Vapour transport: highly porous, hydrophobic) PVDF nanofiber Nanoparticle coating Electrospun with nanoparticle coating is super hydrophobic (Contact angle = 153 deg),with good flux and no wetting PVDF S-PVDF 50 PVDF I-PVDF S-PVDF I-PVDF Commerical PVDF Permeate Conductivity (ms) Time 4 (hr) 6 8 Time (hr) 0 0 Liao et al. JMS 425 & 440 (2013) 18 EWI Project

19 Forward Osmosis - Still a hot topic Publications FO in title Web of Sci., Aug, 2015 Title 19

20 FO Membrane Evolution at FO TFC Hollow Fibers A increases, B/A decreases S parameter decrease 20

21 FO Processes FEED Membrane Draw Regen PROD CT Draw I (Engineered) + regeneration process - Various options Feed Regen Water Desalination FOMBR Draw II (Available) diluted for use / discharge - Seawater, brine, etc Feed Seawater, brine, etc Concentrated Feed Diluted Draw Concentration Pretreatment Dilution 21 PRO

22 FO to reduce Produced Water volumes using thermal brines Thermal desal brine Produced water FO Diluted brine 50% Vol reduced Deep well injection Temperature Orientation ConocoPhillips Global Water Sustainability Centre, Qatar & (Desal. in press) 22

23 Pressure-retarded Osmosis PRO hollow 15 bar has power density of 20 W/m 2 Statkraft Optimum Pressure ~ 25 bar Best membrane/module? Bench mark has been 5W/m 2 EWI Project IRIS Power generated from SWRO brine ~ 15 bar 20 W/m kwh/m 3 brine. 2 Reduce net energy for SWRO plant 23

24 Membrane Bioreactors A key component in Reuse/Reclamation Membrane bioreactor(s) or MBR in title ANAEROBIC Membrane bioreactor(s) or MBR in title Peak interest? Growing interest? 24

25 MBR Future Trends Anaerobic MBRs are gaining interest Potential for net energy production Reduces GHG emissions of wastewater treatment produced used P.McCarty et al. ES&T, 45 (2011) Anaerobic Fluidized Bed MBR (Inha/Stanford) Singapore: EWI Project: (Inha/Stanford/NTU) 25

26 Outline Context Status Research Developments Roadmap and the Future Conclusions 26

27 US Roadmap report (2003)

28 Angewandte Chemie Int.Ed. 54, (2015) 28

29 * RO/NF Possible Futures for Membrane Processes in Water * Angewandte Chemie Int.Ed. 54, (2015) Cohen-Tanugi et al. EES (2014) 7. Assume : Permeability increased 3X Potential energy savings: SWRO (15% - (25%)) & BWRO (45 %) Potential module savings (higher flux): SWRO (15 to 25%) & BWRO (40 %) 29

30 Flux vs Permeability A Limited by mass transfer k J = A (DP exp (J/k).DP) Increase K DP = 50 bar DP = 25 bar Assume: perfect rejection, no fouling. typical k Typically: A = l/m 2.hr.bar k= 100 l/m2.hr (= 28x10-6 m/s) UPMs require Modules with enhanced Mass Transfer, k

31 Novel spacer design. Strategies for improved k Mass transfer coefficient Various spacers Chong et al. EWI Project 3 D printed prototypes Pressure drop Unsteady-state shear to enhance mass transfer k Other Vibrations Partl Fluidization Gas Sparging VSEP Zamani, Chew et al, Desal. 356, (2015) Increase of k by 2x to 3x possible. Easier with hollow fibers! 31

32 Evolution of RO Permeability Advances in material science UPM potential Carbon NT Graphene Aquaporin Practical upper limit required Fane,Wang,Hu, Angew Chemie Intl, 54 (2015), 3368 Getting close to upper limit of useful permeability Constraint is module design and mass transfer 32

33 Reducing primary energy - SWRO kwh/m3-2.2 kwh/m3 Intake Pretreat UF/MF RO plant Post-treat Energy Recovery 33

34 Reducing primary energy - SWRO Potential to almost halve membrane energy demand Trade off is additional capital & foot print kwh/m3-2.2 kwh/m3 Intake Pretreat UF/MF RO plant Post-treat Energy Recovery BSUF, Biofilt etc kwh/m3 UPM RO Close to OP operation PRO power -1.6 to kwh/m3 kwh/m3-1.3 to -1.4 Gravity driven biostabilized Close to osmotic pressure multistage or CCD

35 FO RO Hybrids I. FO dilution reduces osmotic pressure of SWRO feed. low salinity stream (WWRO) seawater FO (1) RO II. FO (as PRO) recovers osmotic power from RO brine. Brine FO is 1 dilutes diluted seawater prior to with discharge. energy benefit to SWRO. PRO 2 recovers energy from brines and dilutes SW brine. seawater RO low salinity stream Potential to halve energy / m 3 water product. Trade offs FO (2) [PRO] Product has impaired water origin. Requires collocation of SWRO and Water Reuse plant. brine Cath et al., JMS 362 (2010) Sim et al. Membrane, (2013) D Kim et al. JMS 483 (2015) dilute brine 35

36 Possible Futures for Membrane Processes in Water * UF/MF * Angewandte Chemie Int.Ed. 54, (2015) 36

37 Comparison of Longitudinal and Transverse Vibrating Hollow Fibre Membranes Expt CFD Transverse vibrations upto 5x the maximum shear rate and upto 1/20 th the TMP rise. Could this apply for RO for enhanced k? Zamani, Law, Fane, JMS 429 (2013)

38 Possible Futures for Membrane Processes in Water * Membrane Bioreactors (An)MBR RO * Angewandte Chemie Int.Ed. 54, (2015) 38

39 FO-MD Anaerobic MBR Reversible fouling tendency of FO membranes an advantage UASB FO ( HF) MD (55 C) Product < 5 ppm TOC, TN Biogas at ~ 75% theoretical Stable fluxes > 10 LMH Q H FO MD DS 0.5M NaCl Potential for net energy production and reclaimed water 39

40 Possible Futures for Membrane Processes in Water * MD FO/PRO * Angewandte Chemie Int.Ed. 54, (2015) 40

41 Y (mm) Some Final Comments on Trends Decarbonisation-Desalination and Renewable Energy Fouling Control and Sensors, Smart Systems AC current vs frequency Membrane Feed Retentat e Permeate Spacer X (mm) Flow Voltage electrodes V V Impedance + - Spectrometer I - 41

42 A Global Role Model Singapore and Water: Reclamation (NeWater) & SWRO Reclamation > SWRO SWRO NeWater Energy and cost to reclaim/reuse is ~ 50% SWRO Desalinate 1 x and Reuse multiple times. Consider the hybrid FO RO PRO option. Anticipate growth in MBR-RO and AnMBR-RO.

43 Conclusions & Targets for A Road Map Aim for 3 (to 5) fold increase in RO permeability. At same time more robust and cost effective membranes. Increase mass transfer k by 3 to 5x (novel hydrodynamics). SWRO: 50% less energy ( novel memb, module, process F/S). FO & MD optimized to exploit renewables (osmotic, thermal). FO, PRO, MD, RO integrated processes. WW reclamation with AnMBR +RO (recover biogas,p etc). WWRO > SWRO, integrate and collocate to lower energy. Enhanced efficiency & energy usage from improved fouling control, novel sensors, smart systems etc. 43

44 ACKNOWLEDGEMENTS EDB Singapore and Environment and Water Industry Programme Office (EWI) under National Research Foundation (NRF) for supporting the Singapore Membrane Technology Centre. The Family 44

45 NTU THANK YOU ANY QUESTIONS? Cleantech One Home of 45

46 High Retention MBRs (ORT = HRT, to improve permeate quality) W/W H 2 O Membrane Distillation Bioreactor (MDBR) M Driving force : waste heat. Fane et al. PCT/SG2006/ Low GHG options Phattaranawik et al., Chem. Eng & Techol., 32 (2009) W/W S A Q H Fluxes ~ 10LMH Forward Osmosis Bioreactor (FOMBR) M X H 2 O Lay et al. SST 47 (2012) Zhang et al. JMS 403 (2012) S A Q H 46

47 Water Reclamation Future trends : MBR + RO MBR RO B.Wu et al. Desalination 311 (2013) Toray / Low efficiency biotreatment Zhang,J. JMS 284 (2006) High efficiency biotreatment RO fouling depends on MBR performance. Potential for very low DOC. CDOC retention ~ 95% 47