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Natco presentation about produced water
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PRODUCED WATER TREATMENTCARACAS, VENEZUELANOVEMBER 6-7, 2001
By: Kevin JunielSenior Process Engineer
NATCO Group Houston, TX
Outline•INTRODUCTION•WHAT IS PRODUCED WATER?
•PROPERTIES OF PRODUCED WATER
•ENVIRONMENTAL ISSUES
•HOW IS PRODUCED WATER HANDLED?
•WHY TREAT PRODUCED WATER?
•WATER CHEMISTRY ISSUES
•HOW TO TREAT PRODUCED WATER
•SUSPENDED OIL REMOVAL
•SUSPENDED SOLIDS REMOVAL
•CHEMICAL TREATMENT
•BACKWASH WATER TREATMENT
•MATERIAL SELECTION ISSUES
•CONCLUSION
• Sources
• Formation Water
• Water-flood water
• Water from operations- i.e. kill fluids
• Chemicals from treatment
Produced Water Sources
Platform
Seawater Injection
SubseaSafetyValveSafety
Chemicals
Oil Injection Water
Ocean Surface
Bottom of Ocean
Produced Water Sources
Formation Water
Components in Produced Water
� Water� Organics� Salts� Solids� Biological Matter� Added Materials� NORM – Naturally
Occurring Radioactive Material
Typical Composition
Water,% 90 to 99.9
Organics,% 0.1 to 0.2
Salts,ppm 100 to 350000
Solids,ppm 10 to 50
Bacteria,colonies/ml 10,000
Example Produced Water
- 10,000 BWPD
- 1000 ppm oil of 34 º API
- 100 ppm solids of SG = 2.0
- 10 ppm dissolved organics
- 50,000 ppm TDS , SG = 1.03
- 100 °F @ 100 psig
Salinity
Gulf of Mexico
Seawater 27,000 to 44,000 mg/l
mostly sodium chloride
New Mexico field 75,000 mg/l
mostly magnesium sulphate
Environmental Regulations
�GOVERN EMISSIONS INTO WATER, AIR OR LAND (MUST HAVE UNDERSTANDING OF IMPACT ON ENVIRONMENT)
�DICTATE LEVEL OF TREATMENT FOR DISPOSAL INTO WATER BODIES (INTERNATIONAL, FEDERAL, STATE AND LOCAL)
�CHANGE IN REACTION TO DEVELOPING TECHNOLOGY (HOWEVER PRESSURE TO INSTILL TIGHTER LIMITS)
�NON-COMPLIANCE CAN BE DEVASTATING FOR OPERATORS
�INVESTMENTS IN ENVIRONMENTAL COMPLIANCE DO NOT SHOW UP ON THE BOTTOM LINE – OR DO THEY?
How Produced Water is Handled
• Disposal (Surface, Subsurface)
• Enhanced Recovery (Waterflood, Steamflood)
•Agriculture (Irrigation)
•Process/Plant Water
•It is estimated that the produced water volume will reach 3-6 times the oil volume over the life of an oilfield
Produced Water vs. Life of OilfieldQ
uant
ity
Time
Water
Oil
Gas
What is Water Treatment?
1. PREPARE WATER FOR INJECTION INTO WATERFLOOD OR DISPOSAL ZONE
2. PREPARE WATER FOR OVERBOARD/SURFACE DISPOSAL
3. UTILITY AT FACILITY
4. AGRICULTURAL USE
5. RECOVER OIL TO RE-ROUTE TO THE CASH REGISTER
Produced Water Treatment Objectives for Oilfield Use
� REDUCE SUSPENDED OIL CONCENTRATION TO COMPLIANCE LEVELS OR TO LEVELS SPECIFIED BY RESERVOIR DEPT.
� REDUCE SUSPENDED SOLIDS CONCENTRATION TO COMPLIANCE LEVELS OR TO LEVELS SPECIFIED BY RESERVOIR DEPT.
� ADDRESS ANY WATER CHEMISTRY ISSUES (CHEMICAL INJECTION SYSTEM)
� EXCLUDE OXYGEN FROM THE SYSTEM
� MINIMIZE CAPITAL AND OPERATING EXPENSE (DOWNTIME)
How Clean Does The Water Need To Be?
”Typical” Waterflood
• Solids < 5-10 mg/l
•Oil< 5-10 mg/l
• 95% removal of 5+ micron
Overboard in US GOMOil 42 mg/l daily max., 29 mg/l monthly avg.
Water Chemistry Issues
� HIGH DISSOLVED SOLIDS CONTENT
� HIGH SCALING TENDENCY
� MIXING PRODUCED WATERS
� MIXING PRODUCED WATER AND SURFACE WATER
� CORROSION POTENTIAL/CORROSION CONTROL
� CONTROL OF BACTERIA GROWTH (AEROBIC/ANAEROBIC)
Open System Versus Closed System Design
� ADVANTAGES OF CLOSED SYSTEM
1. EXCLUDE OXYGEN2. MINIMIZE CORROSION3. MINIMIZE SCALE
FORMATION4. MINIMIZE AEROBIC
BACTERIA5. PRESERVE PROCESS
HEAT6. EXCLUDE OUTSIDE
CONTAMINANTS7. MINIMIZE EMISSIONS
� ADVANTAGES OF OPEN SYSTEM
1. CHEAP TO BUILD
REVIEW
1. WHAT IS PRODUCED WATER?2. WHY MUST PRODUCED WATER BE TREATED?3. HOW IMPORTANT IS PRODUCED WATER TREATMENT TO
AN OPERATING FACILITY?4. WHY IS A CLOSED SYSTEM PREFERRED?5. WHAT MUST BE CONSIDERED WHEN MIXING
PRODUCED WATER WITH FRESH WATER?6. HOW DOES PRODUCED WATER TEEATMENT AFFECT
PROFITABILITY?7. WHAT ARE SOME USES OF PRODUCED WATER IN AN
OILFIELD OPERATION?8. HOW CLEAN MUST PRODUCED WATER BE?
Process Definition
�Bulk oil removal
�Free oil removal
�Dispersed oil removal
�Water polishing
�Proposal / injection
Processes That Treat Produced Waters
• Specific Gravity Differences
•Flotation
•Enhanced Gravity
• Physical trapping
•Chemical Treatment
SUSPENDED OIL/SOLIDS SETTLINGSUSPENDED OIL/SOLIDS SETTLINGSTOKES LAWSTOKES LAW
=V
F�sg(water-oil)(d2)V =�
where:
V = particle moving velocityF = force
� sg = densityd = droplet size� = viscosity
FACTORS AFFECTING PERFORMANCE BASED ON STOKE’S LAW
1. DROP SIZE2. TEMPERATURE (VISCOSITY,DENSITY)3. GRAVITATIONAL FORCE
HENCE, OUR GOAL IN PROCESS SYSTEM DESIGN IS TO MAXIMIZE OR ENHANCE THE FACTORS TO PROMOTE GOOD SEPARATION. EXAMPLES…..
Bulk Oil Removal (Gravity)
TECHNOLOGY PURPOSE
Skim Tanks
Horizontal Skimmers
Vertical Skimmers
API Separators
Mitigate flow surges
Evolve entrained gas
Reduce oil concentrations
Provide solids settling
Horizontal SeparatorOil droplets >150 micronsSettleable solids >50 micronRetention time <10 minutes
Onshore / Offshore Production Surge ProtectionPotential Pitch & Roll Concerns
Vertical Separator
Oil droplets >150 microns
Settleable solids >25 micron
Retention time <10 minutes
Offshore Production
Minimal Surge Protection
Less Sensitive to Pitch / Roll
API SeparatorOil droplets >150 micronsSettleable solids >50 micronRetention time 20 + minutes
Refinery Waste WaterIndustrial Waste Water
API Separator Options
� Inlet Distribution Headers for Flow Control
� Solids Hopper for Solids Collection
� Flight and Rake System for Solids/Oil Removal
� Adjustable Rotating Pipe Skimmer for Oil Removal
� Rotating Drum Skimmer for Enhanced Oil Removal
� Corrugated Plate Pack for 50 Micron Oil Droplet Removal Efficiency
Free Oil Removal
TECHNOLOGY PURPOSE
Corrugated Plate Interceptors(Upflow or Downflow )
Matrix PlateSeparatorsLiquid/Liquid HydrocyclonesSolid/Liquid Hydrocyclones
Primary separation of oil from
water
Primary separation of oil free
solids from water
Down Flow CPI
�Oil Removal (Gravity)
�Plates at 45º Angle
�Plate spacing 18mm
�Plate pack material is
316SS or FRP
Coalescing Plate
Up Flow CPI
�Solids Removal (Gravity)
�Plates at 60º Angle
�Plate spacing 25mm
�Plate pack material is
316SS or FRP
Matrix Plate Separators (Gravity)Oil droplets d90 @ 50 micronSettleable solids d50 @ 25 micronVelocity 1–3 ft/min
Onshore / Offshore ProductionMinimal Surge ProtectionInsensitive to Pitch / Roll
REVIEW
1. DESCRIBE STOKE’S LAW?2. WHAT ARE COMMON WATER TREATING PROCESSES THAT ARE
BASED ON STOKE’S LAW?3. HOW DOES THE SIZE OF THE OIL DROPLET AFFECT THE
PERFORMANCE OF OIL REMOVAL EQUIPMENT?4. WHICH OIL WILL PERFORM BETTER – 16 API OR 34 API?
WHY?5. HOW DO PLATE SEPARATORS WORK?6. WHICH ORIENTATION IS BETTER FOR SEPARATION –
HORIZONTAL OR VERTICAL?7. WHICH ORIENTATION IS LESS SENSITIVE TO MOTION –
HORIZONTAL OR VERTICAL?8. WHAT IS THE ADVANTAGE OF ADDING MATRIX PACKING TO A
SKIMMER OR SEPARATOR VESSEL? WHAT ARE POTENTIAL DISADVANTAGES OF THIS TYPE OF INTERNALS?
Liquid/Liquid Hydrocyclones
Enhanced GravityConvert Pressure Energy to Centrifugal EnergyInsensitive to Motion or SurgesNo Chemicals or Power (if high enough pressure)Small Oily Reject Stream (2% of Inlet Flow)
Liquid/Liquid Hydrocyclones
Operating Principles� Internal geometry creates a vortex (inlet,taper)� Centrifugal force accelerates separation� Oil droplets separate and coalesce in the center� Oil is funnelled into the overflow for removal
PRINCIPLE OF OPERATION
L/L Hydrocyclones
� Developed, proven technology
� High efficiency� Flexible, Easy to Expand� Compact Design� Lightweight
L/L Hydrocyclone VesselLiner Bundle
� Easy to Install for Future Expansion � Individually Accessible
Liner Design
Oilspin AVh
Oilspin AV
Oilspin AVi
� Corrosion resistant liner
material
� Erosion resistant liner
material
� Ease of operation
� No moving parts
� Low maintenance
“Typical” PerformanceCorrected Efficiency
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0Droplet daimeter, micron
Prob
abili
ty o
f rem
oval
LQAV"dev 2"
Produced Water Treatment
LPSep
PV
Degasser LC
Liquid/LiquidHydrocyclone
Fuel Gas Supply
PVCFrom HPSeparator
PV
From LPSeparator PC
LC
From TestSeparator
PV
To HazardousDrain
FlowmeterDischarge
LVC
Reject to LPSeparator
L/L Hydrocyclone Construction
�Efficiency equal to or better than all competinghydrocyclones�Internal geometry and Stelliteinlet reduce erosion�Cones : duplex SS Tails: Sanicro 28�Easily installed and removed -no special tools required
Installation
BP GEISUM PLATFORM
NORTH SEA
PRODUCED WATER
23,000 BWPD
OILSPIN AVi INSTALLATION DESIGN
•MINIMIZE SPACE
•MINIMIZE INSTRUMENTS
•INCREASE OPERATING FLEXIBILITY
•OVERALL REDUCTION IN COST
•MAINTAINING HIGHEST EFFICIENCY
OILSPIN AVi - UNLIMITED TURNDOWN!!!
Oilspin AVi Interactive Hydrocyclone
Method of operation - on line
Oilspin AViInteractive Hydrocyclone
Method of operation - off line
Oilspin AVi Interactive Hydrocyclone
Method of operation - on line
Oilspin AViInteractive Hydrocyclone
�Hydrocyclones switched
individually or in groups
�2 years operating
experience on Tyra East
�Ideal for test separators,
frequently changing systems
or difficult separations
H. P.SOURCE
L. P.DRAIN
Oilspin AViInteractive Hydrocyclone
�Eliminates need for multiple or compartmented vessels�Fully automatic hydraulic operation�New manual activation system under development.
H. P.SOURCE
L. P.DRAIN
SUSPENDED SOLIDS REMOVAL
SOLID/LIQUID HYDROCYCLONES
TYPICAL APPLICATIONS
PRODUCED WATER DESANDING
WELLHEAD DESANDING
FILTER PRE-TREATMENT
SAND WASHING
Hydrocyclone Design
•MULTI LINER VESSEL
•D95 >15 MICRONS
•VARIOUS DUMP OPTIONS
•CERAMIC LINERS AVAILABLE
Large Diameter Range
15”
12”
9”
Small Diameter Range
1” Canned
2”Canned
2”Vessel
1” Vessel
1” Cut-away
12 mm Desanders
� d90 5 to 7 microns� Flowrate typically below
0.1 m3/h so huge numbers required
� Very prone to blockage� Upstream strainers or
desanders required for protection
Ceramic Desanders
� Default 3” ceramicdesander
� Flowrate/efficiency modified by vortex finder selection
� Capacity 10 to 30 m3/h each
� Potted underflow or continuous (>2%)
� d90 15 to 50 microns � 2” and 1” also
available taking d90
down to 11 microns
Performance Range
Solid/Liquid HydrocycloneInstallation
�Gamra, Libya Well-head Desanders
�3,700,000 bpd
�90 off 15 PHQ
�95% removal > 100 microns
�Aquifer water
Solid/Liquid HydrocycloneInstallation
�Al Furat Petroleum�Omar Phase II Field, Syria�110,000 bpd�13 off 10 PHQ�95% removal > 40 microns�River water
Mounting arrangements
Solid/Liquid HydrocycloneInstallation
� Anadarko/SonatrachAlgeria
� HBNS Development
� 10 Micron Separation
� 150,000 bwpd� Aquifer Water
� 306 off 2CLQ
Solid/Liquid HydrocycloneInstallation
� Maersk Petroleum Qatar� Al-Shaheen Field� Development
� 98% > 10 micron � rating
� 75,000 BWPD� Produced water
� 146 off 2PHQ
� Used in conjunction with � Oilspin AV LLC’s
High Pressure Wellhead Desander
Halliburton for PDOWelltesting Operations
� Designed to separate solids from multi-phase fluids
� Welltesting and clean up � First fully coded ASME
VIII Division 2hydrocyclone vessel supplied globally
� 3” x 7 way, 10,000 psiunit
Wellhead DesanderShell/PDO Marmul Field
� Compact with high throughput
� Ultra high erosion resistance
� No backflushing� Reduced weight & size
compared with conventional filters
� Continuous or batch operation
Wellhead Desander
� Wide operational envelope� Maintains separation during
slugging, varying flow rates, very high GLR and varying phase composition
� Gas/liquid ratios between 5 and 100 possible
� Higher pressure, higher GLR � Pressure drop 1-15 bar
depending on application� High erosion resistance due
to inlet geometry and materials
Sandwash System
� Designed to separate and remove oil contaminated solids to produce oil free sand (<10g/kg oil on sand by weight)
RECIRCULATION
PROCESSWATER
MOZLEY HYDROCYCLONES
OILYWATER
Sand Cleaning System
� Designed to separate and remove oil contaminated solids to produce oil free sand (<10g/kg oil on sand by weight)
� No chemical addition required� Cleans sand by physical
attrition� Compact system� Maintains cleaning efficiency
with varying solid concentrations Chevron Cabinda Kungulo Field
Desanding Skid for Water Injection Platform
Pressure Let Down Hydrocyclone
� Ceramic cyclonic device for reducing slurry pressure
� Used on desander underflows� Very high erosion resistance� Sized to suit each duty
Sand Fluidizer
� Device under development
� Uses a small amount of water to fluidise and
transport settled sand
� Competitor to Merpro Tore
Centrifuge
REVIEW
1. BY WHAT MECHANISM DO LIQUID/LIQUID HYDROCYCLONES WORK?2. IS HYDROCYCLONE PERFORMANCE AFFECTED BY THE SIZE OF THE OIL
DROPLET?3. WHAT HAPPENS TO HYDROCYCLONE PERFORMANCE AS FLOW RATE
DECREASES? IF A VESSEL HAS 20 LINERS INSTALLED AND THE FLOW RATE DECREASES BY 40%, WHAT ADJUSTMENT MUST BE MADE?
4. HOW DOES THE DIAMETER OF THE SOLID/LIQUID HYDROCYCLONE AFFECT FLOW RATE AND PARTICLE SIZE REMOVED?
5. DESCRIBE HOW THE INTERACTIVE LIQUID/LIQUID HYDROCYCLONE SYSTEM WORKS?
6. WHEN WOULD IT BE APPROPRIATE TO USE POLYURETHANE LINERS IN A SOLID/LIQUID HYDROCYCLONE?
7. WHY IS THE LEVEL CONTROL VALVE PLACED DOWNSTREAM OF THE LIQUID/LIQUID HYDROCYCLONE VESSEL?
8. WHY IS A DEGASSER VESSEL PLACED DOWNSTREAM OF A LIQUID/LIQUID HYDROCYCLONE VESSEL?
Dispersed Oil Removal (Flotation)TECHNOLOGY PURPOSE
Hydraulic Induced Gas Flotation Units
Horizontal Hydraulic IGFHorizontal Sparged IGFSingle Cell Hydraulic IGFHydraulic Column IGFMPE Sparged Column IGF
Mechanical Induced Gas Flotation Units
Separation of emulsified oil from water
Separation of oil coated solids from water
Horizontal Hydraulic IGF�Inlet oil concentration 200-300ppm�Outlet oil concentration 20-30ppm�90-98% Removal Efficiency
Onshore / Offshore
Production
Handles Upsets
Advantages of Horizontal Hydraulic IGF
� No Internal Moving Parts
� Over and Under Internal Baffles to Prevent Short Circuiting
� 25-50 % Water Recycle Rate for Increased Gas Contact Time
� Dual Internal Eductors for Increased Gas Bubble Dispersement
� Mechanical Wipers or Spillover Weirs for Oil Removal
� PVC or 316 SS Internals
� ASME Code Design
� Cylindrical Vessel Design for Improved Solids Collection
Mechanical Induced Gas Flotation(Pressurised)
Cycloturbine� 2 or 4 per vessel� Rotor creates negative pressure
in draft tube, pulling down gas from above the liquid surface
� Gas bubbles are thrown out by the rotor and impinge on the stator
� Turbine design enhances flow pattern and gas/oil contact
CYCLOTURBINES
• 65 SCFM/BBL GAS:WATER RATIOS
• BUBBLE SIZE = <50 MICRONS
• EFFECTIVE DISTRIBUTION
• GEAR REDUCTION DRIVE
AUTOSTABLE SKIMMER
• SITS AT OIL / WATER INTERFACE
• MINIMIZES OIL SKIMS <2%
• HANDLES UPSETS
• OPERATES UNDER MOTION
• NO MOVING PARTS
Floating skimmers
� Oil draw off regulated by oil outlet valve
� Oil box and floating skimmer designed to provide gas seal between water and separated oil
� External buoyancy chambers keep skimmer close to surface
Floating skimmers
� Internal buoyancy chambers regulate skimmer depth and therefore amount skimmed
� Insensitive to motion or throughput
Produced Water TreatmentMechanical Induced Gas Flotation�Maximum operating pressure 4 barg�Maximum inlet oil concentration 1000ppm�Typical efficiency 90-98% oil removal with chemicals�Typical efficiency 80 - 90% without chemicals
Produced Water TreatmentMechanical Induced Gas Flotation
�Typical outlet concentration 15-20 ppm �Typical solids removal 20-50%�Patented by Ceca(Elf) and supplied under licence
Single Cell Hydraulic IGF
Inlet oil concentration 200-300ppm
Outlet oil concentration 30-50ppm
75-90% Removal Efficiency
Onshore / Offshore Production
Handles Upsets
Less Sensitive to Pitch / Roll
Single Cell Sparged IGF
Inlet oil concentration 200-300ppm
Outlet oil concentration 30-50ppm
75-90% Removal Efficiency
Onshore / Offshore Production
Handles Upsets
Less Sensitive to Pitch / Roll
Vertical Downflow Column IGF
Counter Current Contacting
Onshore / Offshore Production
Handles Upsets
Insensitive to Pitch / Roll
Inlet oil concentration 200-300ppm
Outlet oil concentration 20-30ppm
90-98% Removal Efficiency
REVIEW
1. DESCRIBE HOW FLOTATION WORKS.2. WHAT IS THE DIFFERENCE BETWEEN HYDRAULIC
FLOTATION AND MECHANICAL FLOTATION?3. HOW IS OIL REMOVED IN THE HYDRAULIC IGF?4. HOW IS OIL REMOVED IN THE MECHANICAL IGF?5. WHAT CAN AFFECT THE PERFORMANCE OF THE IGF?6. WHAT IS THE MAXIMUM INLET OIL CONTENT THAT THE
IGF CAN HANDLE?
Water Polishing (Physical Trapping)
TECHNOLOGY PURPOSE
Separation of emulsified oil from water
Separation of oil coated fines from water
Media FiltrationNutshell Filter
Cartridge Filter
Produced (Oily) Water Multi-Media Filter
� Proven technology�Dual/multimedia� Anthracite/sand/garnet combinations�Max inlet oil 30-50 ppm�Outlet oil < 5 ppm�Max inlet TSS 30 - 50 mg/l� Efficiency typically 95% removal of particles
> 5 microns
Water Injection SystemsMedia Filters
� Best technology for removing solid particulates from produced water
� Flux rates 15 - 35 m3/m2/h on produced water
� Polyelectrolyte required� Surfactant usually
required for backwash� Gas scour used during
backwashing� Hundreds of operating
references
Media Filter - Installation
MEDIA FILTER INTERNALS
COLLECTION LATERALSINLET DISTRIBUTOR
Backwash Sequence
Nutshell Filter
�Max inlet oil 50-100 ppm�Outlet oil < 5 ppm�Max inlet TSS 30 - 50 mg/l�Efficiency typically 95% removal of
particles > 10 microns (or 90% > 5 microns)
Nutshell Filter
� Effective oil removal filter� Handles waxy oils
without fouling� Solids removal worse
than suppliers claim� Flux rates 30 - 35
m3/m2/h � Polyelectrolyte not
required� Surfactant not required � Sensitive to biocides� Can be retrofitted to
existing filters
Retrofitted
Nutshell Filter
Nutshell Filter
� Normal flow dowward through the crushed nutshell media
� Nutshells are recirculated through the Powerhead to strip off the oil
� Dirty water passes through a screen to drain
� Clean nutshell media returns to the filter vessel
Cartridge Filters
� Polishing filters for produced water where treatment specification is very tight
� Vertical or horizontal vessels
� Cartridges made by Pall and supplied to special NATCO design
� Sized on basis of hydraulic and solids loadings
� Absolute cartridges (cannot be compared with cheap nominal cartridge elements)
� Quick opening and counterbalanced lid designs available
Coalescer Technology for Complex Gas Condensate Application
� Inlet oil up to 10%� Outlet oil below 10 ppm� Used for low flow
applications with small oil droplets
� Ideal solution for gas condensate fields where LLC’s and IGF’s do not work well
Pall Phasesep�
� Does not disarm unlike glass fiber media
� Low Maintenance/ High Reliability
� Effectively handles process upsets� Efficiently separates difficult low IFT liquids� Competitive coalescers lose efficiency as IFT gets below
20 dyne/cm� Surfactants (in sulfur compounds, corrosion inhibitors
and found naturally in hydrocarbons) lower IFT
IFT = interfacial tension
BACKWASH WATER TREATMENT ISSUES
�What are the contaminants?
�Options for removal
�Equipment required
�Concerns
�Experience of the class
DISPOSAL
Discharge / Injection
TECHNOLOGY PURPOSE
Disposal CaissonSkim Pile
Submerged Column Flotation Unit
(SCFU)
No slick no sheen
No disposal well plugging
Skim Pile
• Free Oil Removal from Open Drains
• Internal Baffles with Oil Risers for Improved Separation
• No Solids Build up in Vessel
• No Moving Parts
• Internal or External Oil Removal Pump
• No Deck Space Required
• Minimal Platform Weight
Submerged ColumnFlotation Unit (SCFU)
•Combination of Flotation and Disposal In Single Vessel
• No Deck Space Required
• Minimal Platform Weight (Partially Submerged in Water)
• No Internal Moving Parts
• Low Maintenance
• Insensitive to Motion
• Reduced Installed Cost
This Submerged Column Flotation Unit (SCFU) is installed offshore Brazil on a FPSO. Directly mounted to the hull, this unit is designed to treat 115,000 bpd of Produced Water. The system was installed to eliminate deck space and weight requirements and minimize the impact of pitch and roll on flotation performance – a major concern for conventional vessels.
DISPOSAL METHODSSubmerged Column Flotation Unit (SCFU)
SCFU Installed On Deepwater Floating Production Platform� No Space Available on Topsides for Conventional Flotation
� Serve as Degassing Vessel for Upstream Hydrocyclones
� Final Disposal After Flotation
� Met Outlet Water Specification of 20 ppm
Compact Offshore Produced Water Treatment System
� Minimal Deck Space Required
� Reduced Weight
� No Moving Parts
� Insensitive to Pitch and Roll
REVIEW1. WHAT ARE THE MECHANISMS EMPLOYED TO MAKE THE
MULTI-MEDIA FILTER WORK PROPERLY?2. WHAT ARE THE MECHANISMS USED TO MAKE THE
NUTSHELL FILTER WORK PROPERLY?3. IF A MULTI-MEDIA FILTER IS USED IN OILY WATER
SERVICE, WHAT STEP IS ADDED TO THE BACKWASH PROCEDURE?
4. WHEN ARE CARTRIDGE FILTERS REQUIRED IN PRODUCED WATER?
5. WHAT ADVANTAGE IS OFFERED BY THE SKIM PILE?
Common Produced Water Treating Chemicals
Upstream of Flotation Unit
10-25 ppmBreak Emulsions
Reverse Demulsifier
Downstream of Booster Pumps
10-20 ppmCorrosion Control
Corrosion Inhibitor
Downstream of Booster Pumps
10-20 ppmScale ControlScale Inhibitor
Various400 ppm for 4 hours (intermittent)
Biological Control
Biocide
In Bottom of Filter
2-4 gal. per backwash
Cleanse Oil Off Media Bed
Surfactant
Upstream of Media Filter
0.5-1 ppmFilter AidCoagulant
Upstream of Media Filter
1-2 ppmFilter AidPolyelectrolyte
Normal Dose Point
Dose RatePurposeChemical
Water Analysis as a Diagnostic Tool
Review Information from Manual
Range of droplet sizes removed by various types of de-oiling equipment
MEMBRANE FILTER
CENTRIFUGE
MEDIA FILTER
COALESCER
HYDROCYCLONE
WITH CHEMICAL FLOTATION
PLATE SEPARATOR
API GRAVITY
0.1 1 10 100 1000
Oily Water TreatmentRequired Minimum Design Parameters
Flow Rate Oil/Water
Pressure Available pressure upstream.Required pressure downstream.
Temperature Operating temperature.
Contaminant Loading Oil / Solids/Oxygen/Bacteria.Inlet/Outlet
Chemical Analysis of Water Anions-Cations-pH
Density Oil - Water - Solids.
Particle Size Analysis Oil-Solids
Oily Water TreatmentRequired Minimum Design Parameters
Existing Process Type of equipment and performance.Upstream/Downstream
Motion Characteristics Pitch/Roll/etc.
Design Conditions Temperature/Pressure
Ambient Conditions Environmental Data/etc.
Outlet Requirements Oil/Solids/Bacteria/Oxygen/Pressure/Temperature
Process Design and Control
Review PFD and P&ID’s from PWTS Proposal
SIZING CRITERIA1. Gravity Settling Devices Stoke’S Law for Drop Rise
2. CPI Flux Rate, Drop Size
3. Hydrocyclone Devices Droplet Removal Efficiency,Capacity per Liner
4. Filtration Equipment Flux Rate, Particle Size Removal
5. Flotation Equipment Retention Time per Cell
Performance Testing
1. Suspended Solids
2. Oil Content
3. Biological Content
4. Sampling Techniques
MATERIAL SELECTION ISSUES
CLASS DISCUSSION OF RELEVANT EXPERIENCE IN VENEZUELA
Engineered Systems Approach To Produced/Oily Water Treatment
REVIEW
1. FOR WHAT PURPOSE IS POLYELECTROLYTE USED?2. FOR WHAT PURPOSE IS SURFACTANT USED?3. WHAT TYPE OF TESTING IS RECOMMENDED TO DESIGN
A PRODUCED WATER TREATING SYSTEM?4. HOW CAN WE USE CHEMICAL TESTING TO
TROUBLESHOOT PROBLEMS?5. WHY IS CARBON STEEL SO COMMON IN PRODUCED
WATER SYSTEMS?6. WHAT BASIC INFORMATION IS REQUIRED TO PROVIDE
TO THE EQUIPMENT SUPPLIER?7. WHAT CRITERIA ARE USED TO SIZE MEDIA FILTRATION
EQUIPMENT?
Recommended