overview and roadmap for membrane process development in desalination · pdf...
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SMTC
OVERVIEW AND ROADMAP FOR MEMBRANE
PROCESS DEVELOPMENT IN DESALINATION
Tony Fane
Singapore Membrane Technology Centre
DesalTech 2015, San Diego, Aug 28-29,2015
Member of NEWRI Ecosystem
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Outline
• Context
• Status
• Research Developments
• Roadmap and the Future
• Conclusions
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Global Water Stress
Climate change and economic growth
Context
Source CSIRO
Predicted trend is hotter and drier
2030
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Singapore and Water
Water 274ML/d
Desalination 455
NeWater 500*
Wastewater MBR 23
MBR 2x60 to NeWater
(i) GE Zenon end 2014
(ii) 2016
Reclamation (NeWater) > SWRO
* 2060 Targets
Desal = 30%, NeWater > 50%
6th NEWater
UF/MF etc
SWRO
Power
Gen
PRO
RED
PRO
RED
Biogas
RO
MD
Cryst
Nonsaline
Saline
Sea/brackish Used water
QH
Potable &
Industry
WATER
INPUT
WATER
OUTPUT
POWER
[Potable]
Industry
brine
brine
saline
nonsaline
nonsal
[ED]
[MD]
CASP/UF
MBR
Potable &
Industry
UF/NF/FO
solids
Membranes and the Water Domain Fane, Wang, Hu, Status & Future of Membranes for Water, Angew. Chemie Intl, 54 (2015), 3368
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D Furakawa, 2008, NWRI
2006
~ 14,000 MLD
2013/14
> 35,0000 MLD
12% growth
(G.Pearce)
6
Drinking Water (60%)
+ Pretreatment
MBRs etc
Low Pressure Membranes
Submerged (Suction)
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
Mainly hollow fibre polymeric
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Low Pressure Membranes
Application Share by Market Value as a Function of Time Period for Membrane Filtration in Water & Wastewater 1985-2015
Greame Pearce : The Pearce Report; Low Pressure Membranes (in Prep) IDA Conf: Session S-18, Tues pm Room E
Pretreatment
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Sea water RO: Plants & Modules – Getting Larger
M.Kurihara (Toray)
Sorek, Israel , 624 MLD (2013) largest SWRO plant.
16 inch modules
Vertically aligned
RO growth is 10 to 15%
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M.Kurihara (Toray)
RO Plant – Getting Larger
Mega Ton Water Project (Japan)
Sorek , 624 MLD
Magtaa, 500 MLD
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Outline
• Context
• Status
• Research Developments
•Roadmap and the Future
• Conclusions
- Novel RO Desalination Membranes - Electrodialysis - Membrane Distillation - Forward Osmosis - Bioreactors
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Pendergast & Hoek, Energy & Env.Sci. (2011), 4, 1946-1971
The Quest for ‘Ultra permeable’ (UPM) RO membranes
Graphene
Revolutionary
Evolutionary
Far Now
Hollow Fibres AqP
R.Wang et al., Recent data-submitted
100%
R.Wang et al., JMS 494 (2015) 68-
Flat Sheet AqP
50%
Y Zhao et al., JMS,
423 ( 2012)
Evolutionary & Now
AqPAsia
FS
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Publications CNT
desalination Web of Sci. , Aug, 2015
Publications Graphene
desalination Web of Sci. , Aug, 2015
Title Topic
Title Topic
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Press Release March 25, 2015
Sumedh.S.et al, ‘Water desalination using nanoporous single-layer graphene’ Nature Nanotechnology, 10, (May 2015) , 459-464. FO Mode data:
A value = 70 g m-2 s-1 atm-1 = 250 LMH per bar (> 20 xcurrent)
Support is SiN microchip, Am = 5 micron.
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UPM potential Carbon NT, Graphene
Aquaporin
Evolution of RO Permeability
Fane,Wang,Hu, Angew Chemie Intl, 54 (2015), 3368
Advances in material science
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?
Can we anticipate a ‘step change’ in RO permeability ? Could we use a ‘step change’ in RO Permeability ?
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Electro dialysis Publications Electrodialysis desalination
Web of Sci. , Aug, 2015
Topic Title
EDR desalination brackish river water (200 MLd)
Desal 253 (2010) 170-174
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Process X ?
Sea water feed WHO standard DW
1.5 kWh/ m3
100mm filter UF ED + CEDI Post treat
Evoqua (Siemens WT)
Singapore’s Desal Challenge (2008)
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Membrane Distillation - Long gestation but interest continues
= 1370
~600 in last 4 yrs Publications MD in title Web of Sci. , June, 2015
• ZLD—MD crystallization
• FO draw regeneration
• Novel bioreactors
• Low GHG option
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PVDF nanofiber
Nanoparticle coating
b
a
1
0 2 4 6 8
0
20
40
Flu
x (K
gm-2
hr-1
)
Time (hr)
0
10
20
30
40
50 PVDF
S-PVDF
I-PVDF
Per
mea
te C
ond
uct
ivit
y (m
S)
Novel MD Membranes (Vapour transport: highly porous , hydrophobic)
Liao et al. JMS 425 & 440 (2013)
0 2 4 6 8
0
20
40
Flu
x (
Kg
m-2
hr-1
)
Time (hr)
0
10
20
30
40
50 PVDF
S-PVDF
I-PVDF
Commerical PVDF
Per
mea
te C
on
du
ctiv
ity
(m
S)
Electrospun with nanoparticle coating is super hydrophobic (Contact angle = 153 deg),with
good flux and no wetting.
EWI Project 0901-02-03
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Forward Osmosis - Still a hot topic
Publications FO in title Web of Sci. , Aug, 2015
Title
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FO Membrane Evolution at SMTC
A increases, B/A decreases S parameter decrease
FO TFC Hollow Fibers
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FEED PRODCT
FO Processes
Draw I (Engineered) + regeneration process - Various options
Draw II (Available) diluted for use / discharge - Seawater, brine, etc
Feed
Feed
Seawater, brine, etc
Water
Concentrated Feed
Diluted Draw
Regen
Membrane Draw Regen
Desalination
FOMBR
Concentration
Pretreatment
Dilution
PRO
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FO to reduce Produced Water volumes using thermal brines
FO
Produced water
50% Vol reduced
Deep well injection
Diluted brine
Thermal desal brine
Temperature Orientation
ConocoPhillips Global Water Sustainability Centre, Qatar & SMTC (Desal. –in press)
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Pressure-retarded Osmosis
Statkraft
15 bar 20 W/m2
Bench mark
has been
5W/m2
SMTC PRO hollow fiber
@ 15 bar has power
density of 20 W/m2
Power generated from SWRO brine ~
0.3 - 0.5 kWh/m3 brine.
Reduce net energy for SWRO plant
EWI Project 1102-IRIS-07-01
Optimum Pressure ~ 25 bar Best membrane/module ?
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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 ?
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MBR Future Trends
• Anaerobic MBRs are gaining interest
• Potential for net energy production
• Reduces GHG emissions of wastewater treatment
P.McCarty et al. ES&T, 45 (2011)
Anaerobic Fluidized Bed MBR (Inha/Stanford)
Singapore: EWI Project: (Inha/Stanford/NTU)
produced
used
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Outline
• Context
• Status
• Research Developments
• Roadmap and the Future
• Conclusions
SMTC US Roadmap report (2003)
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Angewandte Chemie Int.Ed. 54, 3368-3386
(2015)
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Possible Futures for Membrane Processes in Water*
* Angewandte Chemie Int.Ed. 54, 3368-3386 (2015)
RO/NF
• Potential energy savings: SWRO (15% - (25%)) & BWRO (45 %)
Cohen-Tanugi et al. EES (2014) 7. Assume : Permeability increased 3X
• Potential module savings (higher flux): SWRO (15 to 25%) & BWRO (40 %)
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Limited by mass transfer k
DP = 50 bar DP = 25 bar Assume: perfect rejection, no fouling.
Increase K
J = A (DP – exp (J/k).DP)
Typically: A = 1.0-2.0 l/m2.hr.bar k= 100 l/m2.hr (= 28x10-6m/s)
UPMs require Modules with enhanced Mass Transfer, k
typical k
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Strategies for improved k
Zamani, Chew et al, Desal. 356, (2015) 328-348
• Unsteady-state shear to enhance mass transfer k
Increase of k by 2x to 3x possible.
Easier with hollow fibers!
Partl Fluidization
Other Vibrations Gas Sparging
VSEP
• Novel spacer design.
3 D printed prototypes
Various spacers
Mass transfer coefficient
Pressure drop
Chong et al. EWI Project
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UPM potential
Carbon NT
Graphene
Aquaporin
Practical upper limit
required
Evolution of RO Permeability
• Getting close to upper limit of useful permeability • Constraint is module design and mass transfer
Fane,Wang,Hu, Angew Chemie Intl, 54 (2015), 3368
Advances in material science
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-0.3 kWh/m3
-2.2 kWh/m3
- 2.5
Reducing primary energy - SWRO
Intake RO plant Pretreat UF/MF
Energy Recovery
Post-treat
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-0.3 kWh/m3
-2.2 kWh/m3
- 2.5
Intake RO plant Pretreat UF/MF
Energy Recovery
Post-treat
- 0.01 kWh/m3
-1.6 to -1.7 kWh/m3
BSUF, Biofilt etc UPM RO Close to OP operation PRO power
+ 0.3 kWh/m3
- 1.3 to -1.4
Reducing primary energy - SWRO Potential to almost halve membrane energy demand
Trade off is additional capital & foot print.
Close to osmotic pressure – multistage or CCD Gravity driven biostabilized
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FO (1) RO seawater
low salinity stream (WWRO)
FO – RO Hybrids
FO (2)
[PRO]
RO seawater
low salinity stream
brine dilutebrine
I. FO dilution reduces osmotic pressure of SWRO feed.
II. FO (as PRO) recovers osmotic power from RO brine.
Brine is diluted prior to discharge. • FO 1 dilutes seawater with energy benefit to SWRO.
• PRO 2 recovers energy from brines and dilutes SW brine.
• Potential to halve energy / m3 water product.
• Trade offs
• Product has impaired water origin.
• Requires collocation of SWRO and Water Reuse plant.
•
Cath et al., JMS 362 (2010)
Sim et al. Membrane, (2013)
D Kim et al. JMS 483 (2015)
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Possible Futures for Membrane Processes in Water*
* Angewandte Chemie Int.Ed. 54, 3368-3386 (2015)
UF/MF
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Comparison of Longitudinal and Transverse Vibrating Hollow Fibre Membranes
Zamani, Law, Fane, JMS 429 (2013) 304
• Transverse vibrations upto 5x the maximum shear rate and upto 1/20th the TMP rise.
• Could this apply for RO – for enhanced k ?
Expt CFD
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Possible Futures for Membrane Processes in Water*
* Angewandte Chemie Int.Ed. 54, 3368-3386 (2015)
Membrane Bioreactors
(An)MBR RO
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UASB FO (SMTC HF)
MD (55 C)
QH
FO MD
• Product < 5 ppm TOC, TN • Biogas at ~ 75% theoretical • Stable fluxes > 10 LMH
Potential for net energy production and reclaimed water
• FO-MD Anaerobic MBR
Reversible fouling tendency of FO membranes an advantage
DS 0.5M NaCl
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Possible Futures for Membrane Processes in Water*
* Angewandte Chemie Int.Ed. 54, 3368-3386 (2015)
MD
FO/PRO
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Some Final Comments on Trends
• Decarbonisation-Desalination and Renewable Energy
• Fouling Control and Sensors, Smart Systems
Flow
0.00.2 0.4 0.6 0.8 1.0
X (mm)
0.2
0.4
0.6
0.8
1.0
Y (
mm
)
Spacer
Feed Retentat
e Permeate
Voltage
electrodes
Membrane
Impedance
Spectrometer
V
+
V
-
I
-
AC current vs
frequency
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SWRO NeWater
Singapore and Water: Reclamation (NeWater) & SWRO
Reclamation > SWRO
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.
A Global Role Model
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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.
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ACKNOWLEDGEMENTS
EDB Singapore and Environment and Water Industry Programme Office (EWI) under National
Research Foundation (NRF) for supporting the Singapore Membrane Technology Centre.
The SMTC Family
http://smtc.ntu.edu.sg
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THANK YOU
ANY QUESTIONS ?
Cleantech One – Home of SMTC
NTU
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High Retention MBRs
M
W/W
S A
M
W/W
S A
X H2O
H2O
Membrane Distillation Bioreactor (MDBR)
Forward Osmosis Bioreactor (FOMBR)
Driving force : waste heat.
Low GHG options
(ORT = HRT , to improve permeate quality)
Fane et al. PCT/SG2006/000165
Phattaranawik et al., Chem. Eng & Techol., 32 (2009)
Fluxes ~ 10LMH QH
QH
Lay et al. SST 47 (2012)
Zhang et al. JMS 403 (2012)
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High efficiency biotreatment
Low efficiency biotreatment
Water Reclamation
Future trends : MBR + RO
CDOC retention
~ 95%
B.Wu et al. Desalination 311 (2013)
Toray /SMTC
RO fouling depends on MBR performance.
Potential for very low DOC.
Zhang,J. JMS 284 (2006)
MBR RO