A Model for Integrated Treatment, Desalting and Reuse of ... · PDF fileA Model for Integrated...

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


PI

FI

TI

Producedwater feed

permeateceramicmembrane

air

Deadend filtration for low oil content in feed water

FiltrationBack flush

CEB unit

Filtration unit

Chemicalcleaning


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


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


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


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


Electrolysis Targeting Commercial Production of:i. Sodium Hydroxideii. Chlorineiii. Hydrogen

Cooling Concentration Cooling

Cooling Drying Liquefaction

Cooling

SodiumHydroxide

Electrolysis

CausticSolution

Chlorine

Hydrogen

Compression


View of the Electrolysis Test Unit

Sample of Results


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

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