1

SMART WATER BY MEMBRANES

Remya Ravindran Nair

February 26, 2016

2

Myself

PhD May 2015 – 2018 Supervisors: Prof. Torleiv Bilstad and Dr. Skule Strand

3

Feed SW Retentate

Permeate

Permeate

Cross Flow Membrane Separation

Membrane is a selective barrier separating ions

4

NF Membrane Process

NF Feed Pressure : 3-15 Bar

5

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

6

Low TDS Water + Chemicals

Smart Water Production Options

Nanofiltration membraneSeawater as feed and reject(retentate) stream from membrane

7

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

8

Why NF for Smart Water

3000 NO

K

6500 NO

K

9

Pretreatment of seawater upstream of water injection on Brae Alpha Platform

10

Thin Film Composite Membrane

Non-woven poly ester support fabric

Polysulphoneporous layer

Poly amide Coating

50 µm

<1 µm

100 µm

11

Membrane Experiments at E 168

Filtered normal sea water with TDS = 31 800 mg/L

NF membranes

12

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

13

NANO – SW- 2540 NANO- BW- 4040

Results: Ion rejection

𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴𝑴 𝑹𝑹𝑴𝑴𝑹𝑹𝑴𝑴𝑹𝑹𝑹𝑹𝑹𝑹𝑹𝑹𝑴𝑴 𝑹𝑹𝑹𝑹𝑴𝑴𝒐𝒐 % = 𝟏𝟏 −𝑪𝑪𝑪𝑪𝑪𝑪𝒇𝒇

∗ 𝟏𝟏𝟏𝟏𝟏𝟏

14

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

16

17

SO42- and PO4

2- spiking effects on Cl⁻ and Na+ separation

Very high solubility in seawater

18

PO42- spiking effects on ions

19

Electric double layer according to Stern’s model (Shaw, 1969).

20

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)

21

Smart Water Formulation

22

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

23

Produced Water for Smart Water

24

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?

25

Marathon oil, 1990, North SeaOffshore SR 90 membrane plant

Barium Scale in Oil Production

26

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

27

Produced Water Treatment

28

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

29

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

31

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

32

Conclusions

No Excess Chemicals

Sulphate Substitution by Phosphate?

Energy Efficient

Produced Water Reuse

Fresh Water Saving

Sustainability

33

Further Research

Treatmentof oily PW

Reduce sulphateconcentration

Reducemonovalent

ions in retentate