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A Model for Integrated Treatment,Desalting and Reuse of High SalinityOilfield Produced Water
Presenter: Essam El-Sayed
Water ResearchCenter
5th Joint KISR-JCCP Environment Symposium15-17 December, 2014
Acknowledgement
The work presented here is partly based on:
• Collaboration project between JCCP & KISR“Feasibility Study for Treatment and Effective Usageof High Salinity Oilfield Produced Water in Kuwait.”JCCP & KISR shared the costs of equipment,operating expenses and manpower in this project.
and
• KISR study on “Potentiality Assessment of MembraneDistillation for Desalting High Salinity OilfieldProduced Water.”
Acknowledgement
The teams involved in the work presented here are:
• From JCCP:T. Torii & N. Ishihara (Aarabian Oil Co. & JX Nippon)M. Shinohara & K. Tsuda (Chiyoda Corp.)F. Ishikawa (Metawater Co.)
• From KISR (WRC):E. El-Sayed, M. Abdel-Jawad, M. Ahmed,M. Tabtabaei, A. Al-Odwani, A. Al-Mesri & J. Thomas
Contents
Background
Objective
The Model Pretreatment ZLD Desalination Downstream of the Desalination
Representative Sample of the Results
Conclusions
The Water Problems in Oilfields
Oilfield produced water is by far the largest volume by-product in oil and gas upstream operations and it isconsidered wastestream
The amounts of oilfield produced water are increasing overthe years due to increasing oil and gas production as well asmaturity of producing wells
Global average production of oilfield produced water during2013 is estimated to be in the range of 240-260 millionbarrels per day (≈ 90 billion barrels per year)
In Kuwait, oilfield produced water is extremely saline (TDS ~150,000 – 250,000 ppm), acidic (pH < 6.7), and highly loadedwith oil, H2S and scaling substances
Background
Options for Managing Oilfield Produced Water
1. Water minimization: avoid wastewater reaching the surface using, e.g.:o Polymer gels to block water producing cracks & fractureso Downhole water separators to separate water from oil and reinject it into the
formations
(neat solution, but is not always possible)
2. Reinjection: inject the produced water into:o The same formations to maintain the reservoir pressure, oro Dispose of the wastewater in other suitable formations;
This solution involves treatment of the injected water for scale and foulingcontrol and may also involve transportation of the water from theproducing site to the injection site (most common in Kuwait)
3. Dispose of to the environment: treat to meet onshore or offshoredischarge regulations or discharge without treatment to disposal ponds(must comply with environmental restrictions)
4. Treatment for beneficial usage: convert waste stream into a valuableresource:o Requires significant treatment to meet the quality of the target useso Especially viable when natural water resources are shrinking or unavailable
Background
The Focus in this Presentation is on Treatment forBeneficial Usage and the Objective is to:
● Present a model of integrated ZLD treatment, desalination and reuse that is specifically developed forhigh salinity oilfield produced water
● Present the experimental setup used to demonstrate the model and verify its practicability and effectiveness
● Present sample results obtained for the different processes involved and to highlight trends in theirperformance
Objective
ZLD Treatment & Desalination Model
Pretreatment stage
Water & salt separation stage
H2SRemoval
MicrofiltrationTreatment
Using CeramicMembrane
Desalination byLow Temperature
FlashEvaporation
orBy Membrane
Distillation
Pure water
WarmLime
Softening
WarmLime
Softening
IonExchanger
IonExchanger
ElectrolysisElectrolysis
Chlor-Alkali process stage
Sludge C++, Mg++, etc.
NaOHCl2H2
Saturated solution
Salt CrystalsSeparation byCentrifugationSaline
WaterFeed
Na2CO3 &polymer coagulant
Salt Crystals
Simple H2S Removal Process
Heatingsteam
Heatingsteam
M
H2S-freeproduced
water feedto ceramicmembrane
Condensatereturn to
boiler
Rawwaterfeed
Feed water tank
To H2S absorber
Microfiltration Ceramic Membrane
Microfiltration Ceramic Membrane
Microfiltration Ceramic Membrane
Microfiltration Ceramic Membrane
PI
FI
TI
Producedwater feed
permeateceramicmembrane
air
Deadend filtration for low oil content in feed water
FiltrationBack flush
CEB unit
Filtration unit
Chemicalcleaning
Microfiltration Ceramic Membrane
PI
PI
FI
FiltrationBack flush
permeate
air
ceramicmembrane
PI
TI
Clossflow filtration for high oil content in feed water
Producedwater feed
CEB unit
Filtration unit
Chemicalcleaning
Microfiltration Ceramic Membrane
Sun Mon Tue Wed Thr
Filtration22.5h
Filtration20.0h
Filtration22.5h
AcidCEB2.5h
AcidCEB2.5h
Filtration20.0h
NaOClCEB1.5h
NaOClCEB1.5h
NaOClCEB1.5h
NaOClCEB1.5h
Typical weekly timeline for operation and cleaning cycles of the MFceramic membrane test unit
LTFE Desalination Unit LTFE Desalination Process Diagram
EXHAUST
STEAM
DISTILLATE
COOLING WATER OUTLET
FEEDSLURRY
COOLING WATER INTLET
P - 4VACCUM PUMP
HX - 2CONDENSER
T - 1SEAL WATER TANK
P - 2Distillate Pump
P - 1Circulation Pump
EV - 1EVAPORATOR
HX - 1HEATER
Vacuum Chamber
Desalination by LTFE
Desalination by LTFE
Formation of Salt Crystals
Desalination by MD
The liquid feed and the liquid distillate (or permeate) are kept incontact with the membrane and maintained at different temperatures
mf1
mf2
md2
md1
md2 > md1mf1 > mf2
FEED(RETENTATE)
ME
MB
RA
NE
DISTILLATE(PERMEATE)
vapor
T1
T2
T I2
T I1
distillate
mem
bra
ne
retentate
feed
Desalination by MD
The temperature difference on both sides of the membranecreates the driving force that transfers pure water vapor
from the feed water side to the distillate side
Th
Tl
Desalination by MD
T
T
T
T
P
P
Circulationpump
Flowmeter
Balance
FreshWatertank
(E)Heater
Flowmeter
Circulationpump
SalineWater
Concentrationtank
MDElement
MD experimental setup
Salt Crystals Separation
Centrifuge: Saturated Solution out & Solids Inside
Salt Crystals Separation
Sample of produced salt crystals
Chlor-Alkali Process
Conditioning of the NaCl Solution by Precipitation (Hot LimeSoftening) and Ion Exchanger
Temp. 60C
pH 10.45
Additive Na2CO3
Polymer flocculent
Target Ca< 10 ppm
Mg< 10 ppm
Target Ca< 0.01 ppm
Mg< 0.01 ppm
Hot Lime Softening Ion Exchanger
Chlor-Alkali Process
Typical Specifications of NaCl Brine Feed to the Electrolysis
Sodium chloride 280-305 g/LCalcium andmagnesium
0.01 ppm
Silicon dioxide 5 ppmSodium sulfate 7 ppmAluminum 0.05 ppmlron 0.5 ppmMercury 0.04 ppmHeavy metals 0.05 ppmFluoride 1 ppmlodine 0.4 ppmBarium 0.4 ppmStrontium 0.5 ppmTotal organic carbon 1 ppmPH 2-11
Chlor-Alkali Process
Basis of the Chlor-Alkali Process
2NaCl + 2H2O → 2NaOH + Cl2 + H22 moles 2 moles 2 moles 1 mole 1 mole
40 g/mole 70.9 g/mole 2.016 g/mole18.016 g/mole58.44 g/mole
1 ton NaCL solution = 0.523 ton NaOH + 0.463 ton Cl2 + 0.013 ton H2
Hydrogen
Chlorine
Concentration & Finishing
Purified NaClBrine
Chlor-Alkali Process
Electrolysis Targeting Commercial Production of:i. Sodium Hydroxideii. Chlorineiii. Hydrogen
Cooling Concentration Cooling
Cooling Drying Liquefaction
Cooling
SodiumHydroxide
Electrolysis
CausticSolution
Chlorine
Hydrogen
Compression
Chlor-Alkali Process
View of the Electrolysis Test Unit
Sample of Results
Microfiltration Ceramic Membrane
After Filtration Before Filtration
Sample Results
Example of Filtrate Water Quality from MF Ceramic Membrane Unit
No Item Unit RUN4 RUN5 RUN6 RUN7 RUN8 RUN9 RUN10
1 Turbidity NTU 0.18 0.31 0.11 0.42 0.99 0.65 0.44
2 TOC mg/l 2.105 2.09 1.926 1.529 1.683 x x
3 Oil and Grease mg/l 1.9 1.2 1.2 1.2 0.9 1.5 0.4
4 TDS mg/l 256192 262336 262624 262624 261348
Turbidity of Feed Water 13.7 – 20.8TOC in Feed Water > 5 mg/lOil & Grease in Feed Water 5.7 – 17.8 mg/l
Sample Results
No Item Unit Run No.2 3 4 5 6 7 8 9 10 11 12
2 pH - 8.9 8.8 8.9
5 TDS mg/L 109 24 41 52 28 32 20 8 44 x 92
6 Conductivity mS/m 0.04 0.05 0.03 0.04 0.04 0.04 0.04 0.04 0.04 0.03 0.04
8 TOC mg/L x x 1.9 1.5 1.1 0.9 x x x x x
10 Aluminum mg/L 0.003 0.005 <0.05 0.001 0.053 0.060 <0.05 <0.05 <0.05 <0.05 x
11 Ammonia mg/L 14.0 10.5 12.5 16.0 13.5 18.0 13.0 12.0 15.0 10.0 9.0
12 Arsenic mg/L <0.01 <0.01 0.0003 0.0016 <0.05 <0.05 0.032 0.053 0.066 0.069 x
13 Barium mg/L 0.001 0.017 0.0007 0.0004 0.0001 0.0005 <0.05 <0.05 <0.05 <0.05 x
15 Boron mg/L 0.02 0.01 0.02 0.03 0.04 0.03 <0.05 <0.05 <0.05 <0.05 x
18 Chloride mg/L 14.0 11.5 17.0 25.5 16.0 21.0 19.0 14.0 12.5 22.0 13.0
19 Copper mg/L <0.01 0.0005 0.0005 0.0005 <0.05 <0.05 x x <0.05 <0.05 x
20 Fe(ii) mg/L x x 0 0.007 0.017 0.002 x x x x x
23 Lead mg/L 0.0006 0.002 0.0008 <0.05 0.0024 0.0022 0.0023 0.0012 0.0029 <0.05 x
24 Lithium mg/L 0.0001 0.0002 <0.05 <0.05 <0.05 <0.05 0 0 0 <0.05 x
26 Manganese mg/L 0.0003 0.0067 0.0002 0.0002 <0.05 <0.05 <0.05 <0.05 0 <0.05 x
27 Mercury mg/L <0.01 <0.01 0.006 0.0079 0.245 <0.05 0.009 0.0133 0.0123 0.0069 x
32 Potassium mg/L 0.0306 0.0525 0.0169 0.0073 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 x
34 Sodium mg/L 0.4244 0.7624 0.3079 0.1574 <0.5 <0.05 <0.05 <0.05 <0.05 <0.05 x
35 Strontium mg/L 0.0052 0.0094 0.0019 0.0009 <0.05 <0.05 <0.05 <0.05 0.0017 0.0005 x
38 Total Iron mg/L 0.0205 0.2961 0.0024 0.0031 0.0046 0.0103 0.0044 0.0035 0.0066 0.016 x
41 Zinc mg/L <0.01 0.0173 0.0002 0.0003 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 x
Results of LTFE Distillate Analysis
Sample Results
Results of LTFE Salt Analysis: 5g of crystallized salt dissolved in1 liter of distilled water
Item Unit Run No.
2 3 4 5 6 7 8 9 10 11 12
TDS l 4,868 4,832 4,992 4,932 5,392 5,168 4,964 4,948 4,992 4,580 5,228
Bicarbonate mg/l 10.0 14.6 14.6 15.0 15.4 15.8 15.3 15.7 15.6 16.2 16.6
Calcium mg/l 7.5 15.1 13.2 17.3 14.7 15.4 15.3 11.7 13.9 19.0 18.0
Chloride mg/l 3,050 3,720 3,720 3,770 3,740 3,660 3,660 4,240 3,960 3,640 4,410
Magnesium mg/l 1.07 2.53 2.02 2.65 2.09 2.31 2.21 1.65 1.89 2.97 2.62
Silica asSiO2
mg/l 0.03 0.09 0.07 0.06 0.08 0.07 0.04 0.03 0.05 0.09 0.08
Sodium mg/l 1,688 1,656 1,702 1,679 1,657 1,656 1,646 x x x x
Strontium mg/l x x x x x x x x x x x
Sulfate mg/l 1.00 2.00 3.00 2.00 5.00 3.00 2.00 2.00 3.00 2.00 3.00
Sample Results MD Permeability Tests at 50oC Feed Side Temperature
0 40 80 120 160
1
3
5
7
Time(min)
Flu
x(k
g/m
2/h
)
Saline water
Distilled water
0 20 40 60 80 100 120 140 160 180 2000
1
2
3
4
5
6
7
8
9
10
Time(min)
Flu
x(k
g/m
2/h
)
Saline Water
Distilled Water
0 40 80 120 160 200 240
1
3
5
7
9
11
Time(min)
Flu
x(k
g/m
2/h
)
Saline water
Distilled water
Polypropylene 1
Polyvinylidene fluoride 2
Polyvinylidene fluoride 1
Sample Results MD Permeability Tests Using Different Membranes at Different
Feed Water Temperatures
40 50 60 70 801
3
5
7
9
11
13
15
17
Temperature (oC)
Flu
x(kg
/m2
.h)
PP1
PVDF2
PVDF1
Sample Results Properties of MD Permeate for Feed Side Temperature at 50oC
Membrane
type
Conductivity
(µs)
Total dissolved
solids
(ppm)
Total
carbon
(mg/L)
Total
inorganic
carbon
(mg/L)
Total organic
carbon
(mg/L)
phRejection
Factor
PP1 817 543 67.55 34.13 33.42 7.15 0.995
PVDF1 650 415 43.17 3.01 40.16 7.21 0.995
PVDF2 614 308 91.36 48.46 42.9 7.15 0.996
Sample Results
Comparison Between Ion Compositions in Kuwait’s NaCl Brineand Standard Brine for the Chlor-Alkali Process
※1 : Ca+Mg<0.02ppm
Element unitBrine from Kuwait(after treatment)
Standard Brine warning level methods of analysis
Sr ppm 0.007 0.001 0.1 ICP
Ni ppm 0.01 0.01 0.01 ICP
Fe ppm 0.14 0.02 1 ICP
Ti ppm 0.005 ICP
Ba ppm 0.008 0.005 0.1 ICP
I ppm 0.36 0.07 0.1 ICP
Ca ppm 0.015 0.005 0.02 ※ ICP
SiO2 ppm 0.7 1.7 5 ICP
Al ppm 0.01 0.01 0.1 ICP
Mg ppm 0.006 0.005 0.02 ※ ICP
TOC ppm 5 5 10680° C combustion
catalytic oxidation
method
Na2SO4 g/L 0.2 10 ICP
P ppm 0.18 0.07 ICP
Sample Results Evaluation Parameters of Electrolysis Performance
Cell voltage (C.V.)[V]
Voltage of the anode and the cathode.
Current efficiency (C.E.)[wt%]
The rate of the actual quantity of production to thetheoretical quantity of production.
Electrical power consumption rate(PC)[DC-kWh/t-NaOH]
Electric energy required to manufacture 1 t of caustic soda.
Sample Results Comparison of Electrolysis Performance Using Kuwait NaCl with
Standard NaCl
2.9
3
3.1
3.2
0 1 2 3
C.V
.[V
]
Cell
Kuwait-1
Kuwait-2
standard-1
standard-2
95
96
97
98
99
100
0 1 2 3
C.E
.[%
]
Cell
Kuwait-1
Kuwait-2
standard-1
standard-2
Sample Results Comparison of Electrolysis Performance Using Kuwait NaCl with
Standard NaCl
2050
2070
2090
2110
2130
2150
0 1 2 3
PC
(kW
h/t
Na
OH
)
Cell
Kuwait-1
Kuwait-2
standard-1
standard-2
Ceramic membrane microfiltration combined with H2S strippingcan be used effectively as pretreatment of high salinity oilfieldwater feeding into ZLD desalination processes.
The LTFE process is capable of desalting high salinity oilfieldproduced waters (> 250,000ppm) and produce distillate < 100ppm(ammonia 10.5 – 18 ppm).
Similarly, the MD process in general appears capable of desaltingthis water and produce permeate < 500ppm. Further investigationof the MD made from different membrane materials is needed todraw solid conclusions on its performance.
NaCl salt produced from the oilfield produced water can beconveniently and safely used in chlor-alkali process to add valueto the proposed ZLD treatment and desalination model.
Generally, it can be said that the ZLD treatment, desalination andreuse model presented here offers practical and powerful solutionfor effective management of oilfield produced water, especiallywhere high salinity is encountered.
Conclusions