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SMART WATER BY MEMBRANES
Remya Ravindran Nair
February 26, 2016
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Myself
PhD May 2015 – 2018 Supervisors: Prof. Torleiv Bilstad and Dr. Skule Strand
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Feed SW Retentate
Permeate
Permeate
Cross Flow Membrane Separation
Membrane is a selective barrier separating ions
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NF Membrane Process
NF Feed Pressure : 3-15 Bar
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Smart Water for Carbonates
Produced by adjusting ionic composition in seawater
Retentate from NF membranes
Low Monovalent Ions(Na+ , Cl-)
High Divalent Ions (SO4
2-, Ca2+, Mg2+)
Smart Water
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Low TDS Water + Chemicals
Smart Water Production Options
Nanofiltration membraneSeawater as feed and reject(retentate) stream from membrane
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Power Consumption for Smart Water OptionsFresh Water NF RO MSFD
Pressure(Bar) 5 9 40
Feed(l/h) 950 275
Permeate(l/h) 50 50
Retentate(l/h) 900 225
Note 1 Reject used Permeate usedWater injection flow rate
(m3/hr) 108
Note 2 17 KWh/m3 for MSFD SW required for Smart
water (m3/hr) 114 594
Pump efficiency 60 % 60 % 60 %
Power, kW 6,9 47,5 1100 1836
Area/Membrane(m2) 2,3 2,7
Price(NOK)/ element 3000 6500No. of membranes 120 2160
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Why NF for Smart Water
3000 NO
K
6500 NO
K
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Pretreatment of seawater upstream of water injection on Brae Alpha Platform
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Thin Film Composite Membrane
Non-woven poly ester support fabric
Polysulphoneporous layer
Poly amide Coating
50 µm
<1 µm
100 µm
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Membrane Experiments at E 168
Filtered normal sea water with TDS = 31 800 mg/L
NF membranes
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PermeateDecrease of Ca2+ , Mg2+ , SO4
2-
Increase of Na+ and Cl-
Retentate/ProductIncrease of Ca2+ , Mg2+ , SO4
2-
Decrease of Na+ and Cl-
or
MF
NF
SO42- spiking
Ca2+ spiking
Mg2+ spiking or
Sea Water
orPO43- spiking
pH adjustmentor
Membrane Experiments
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NANO – SW- 2540 NANO- BW- 4040
Results: Ion rejection
𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴 𝑹𝑹𝑴𝑴𝑹𝑹𝑴𝑴𝑹𝑹𝑹𝑹𝑹𝑹𝑹𝑹𝑴𝑴 𝑹𝑹𝑹𝑹𝑴𝑴𝒐𝒐 % = 𝟏𝟏 −𝑪𝑪𝑪𝑪𝑪𝑪𝒇𝒇
∗ 𝟏𝟏𝟏𝟏𝟏𝟏
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SO42- and Mg 2+ spiking effects on Cl⁻ and Na+ membrane separation
Cl- rejection decreased Na+ rejection decreased
Ion spiking of feed water
15Gupta et al. 2011 – ExxonMobil
Effect of Phosphate on Oil Recovery
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SO42- and PO4
2- spiking effects on Cl⁻ and Na+ separation
Very high solubility in seawater
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PO42- spiking effects on ions
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Electric double layer according to Stern’s model (Shaw, 1969).
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Results from NF experiments
Ions Retentate,mmol(ppm) Permeate,mmol(ppm)Cl- 523 (18585) 461 (16365)
SO42- 28.8 (2767) 0.15 (14.74)
Na+ 466 (10725) 410 (9415)Ca2+ 12.7 (509) 1.90 (76)Mg2+ 53.4 (1298) 5.7 (139)PO4
3- 43.08 (4091) 2.9 (282)
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Smart Water Formulation
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Filtered SeawaterNF
RONF Permeate
NF Reject
RO Feed
RO Reject
RO Permeate
Smart Water
TDS = 10 000 – 28 000 ppm
Element ppmNa 10800Cl 19500Ca 400 Mg 1200SO4 2500TDS = 34400
Element ppmNa 9300Cl 16700Ca 350Mg 1000SO4 2400TDS = 29750
TDS < 500 ppm
Combination of NF and RO membrane for smart water production
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Produced Water for Smart Water
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Major Challenges
HIGH TDS
HIGH OIL CONTENT
NEED GOOD TREATMENT SMART WATER
HOW DO WE MAKE SMART WATER FROM HIGH OIL AND TDS CONTENT OF PRODUCED WATER?
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Marathon oil, 1990, North SeaOffshore SR 90 membrane plant
Barium Scale in Oil Production
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The final aim is:
- Remove barium ions from oil-free produced water to prevent scaling
- To increase concentration of the determining ions in barium-free
brineNF suits for both purposes!
Prevention of Scaling
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Produced Water Treatment
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FeedSynthetic
PW
Dilution1:1.5
Dilution 1:3.5
NANO-BW-4040
EM-NF-1812-50
NANO-SW-2540
EM-NF-1812-50
NF-270-2540
IC Analysis
Experimental Design for PW
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Ionic composition of original and diluted produced water
Ion Concentration (mg/L)
Original Tor Field PW Dilution 1:1.5 Dilution 1:3.5
HCO3- 122 0 0
Cl- 55522 39015 17000
SO42- 0 0 0
Mg2+ 1560 1040 160
Ca2+ 1560 1040 150
Na+ 30820 22147 7300
K+ 624 416 100
Ba2+ 4.94 50* 200*
Sr2+ 48.72 0 0
TDS 90 262 63 708 24 910
*Original barium concentrations were low and hardly detected by IC analysis. Barium concentration in diluted PW was therefore increasedwithin non-precipitating range upstream NF, enabling realistic measurable rejections.
30Ion rejection by NANO-BW-4040, NANO-SW-2540 and NF-270 (9 bar)
Results
0
10
20
30
40
50
60
70
80
90
100
Na Cl Ca Mg Ba
REJE
CTIO
N,
%L
NANO-BW-4040 - 1:1.5 dilution NANO-SW-2540 - 1:3.5 dilution NF-270 - 1:3.5 dilution
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Nutshell-Filter
Coalescer NF
NF/RO
Permeate
Retentate
Permeate
Retentate
Seawater
Diluted Brine for Re-
Injection
Re-use or Disposal
Produced Water Flow
Undesired increase of Na and Cl
Re-use or Disposal
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Conclusions
No Excess Chemicals
Sulphate Substitution by Phosphate?
Energy Efficient
Produced Water Reuse
Fresh Water Saving
Sustainability
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Further Research
Treatmentof oily PW
Reduce sulphateconcentration
Reducemonovalent
ions in retentate