electrostatics separation technology

Electrostatics Separation TechnolgyProcess Solution Group

Description of Processes & Fundamentals

YOU DRILLED AN OIL WELL...

BUT ALSO PRODUCED.. GAS MUD SALT SAND WATER SULFUR CHEMICALS

TYPICAL PROCESS SCHEMEGAS PROCESSING BULK SEPARATION OIL TREATING WATER TREATING

CRUDE OIL TREATING CONSISTS OF . . . DEHYDRATION DESALTING(REMOVAL OF INSOLUBLE WATER)

(REMOVAL OF MINERAL CONTAMINANTS SOLUBLE IN WATER, AND OF SOLIDS)

DEHYDRATION DESALTINGCRUDE OIL

CRUDE OIL

CRUDE OIL DEHYDRATIONWATER IN A CRUDE OIL PRODUCTION STREAM CAN TAKE SEVERAL FORMS OIL RICH WATER RICH

EMULSIFIED WATER DISSOLVED WATER FREE WATER

STREAM SAMPLE

FREE WATERFree water is either water existing as the continuous phase, or water existing as relatively large dispersed droplets, both of which separate quickly from the oil phase

DISSOLVED WATERMEASURED WATER-IN-OIL SOLUBILITIES

TYPICAL WATER-IN-OIL EMULSION

Seen Through a Microscope

Droplet sizes range from sub-micron to several hundred microns.

Mechanism of Oil Dehydration A Three Step Process Coagulation Counteracting the Droplet Surface Films Flocculation Gathering the Destabilized Drops Together Sedimentation Gravitational Separation of the Phases

Mechanical Forces for Coalescence and Sedimentation

STOKES EQUATIONDescribes Sedimentation Velocity

V

g D ( 2 - 1 ) = 181

2

V = Sedimentation Velocity g = gravity D = Particle (or dispersed droplet) Diameter 1= Density of Continuous Phase 2= Density of Dispersed Phase 1 = Viscosity of Continuous Phase

DEHYDRATION OF CRUDE OILSACCOMPLISHED BY . . . DROP GROWTH OF THE DISPERSED PHASE SEPARATION OF THE LIQUID PHASES BY GRAVITY SETTLING

DROPLET GROWTH ACHIEVED BY COALESCENCEDiameter = 1 mm Volume = 0.5236 mm3 Surface Area = 3.1416 mm2

+Diameter = 1.260mm Volume =1.0472 mm3 Surface Area=4.98 mm2

TOTAL VOLUME UNCHANGED TOTAL SURFACE AREA ONLY 79% OF ORIGINAL

DROPLET COALESCENCESo why does an emulsion not rapidly coalesce and separate into distinct phases? An emulsion is a dispersion that has been stabilized.

WHAT IS AN EMULSION?EMULSIONS ARE TWO IMMISCIBLE PHASES, INTERDISPERSED BY MECHANICAL AGITATION, AND THE DROPLETS STABILIZED BY . . . VISCOSITY DENSITY DIFFERENCE DROPLET SIZES EMULSIFYING AGENTS STATIC ELECTRICAL CHARGE DESCRIBED BY STOKES LAW NOT DESCRIBED BY STOKES LAW

EMULSIFYING AGENTSEMULSIFYING AGENTS OIL HEAVY PARAFFINIC COMPOUNDS HEAVY NAPHTHENIC ACIDS PETROLEUM ACIDS ASPHALTIC COMPOUNDS ORGANIC SOLIDS INORGANIC SOLIDS WATER DROP

ELECTROSTATIC CHARGEIn a flowing process stream where water exists as a dispersed phase in an organic continuous phase, the water droplets tend to acquire a positive excess charge. This causes a repulsive force between droplets.

++++ ---

++++ ---

HOW CAN WE DESTABILIZE THE EMULSION AND INCREASE SETTLING RATE? Heat Chemistry Flow Regime Coalescing Surfaces Electrostatic Fields

Crude oil dehydration utilizes these principles to speed up the coalescence and separation of emulsified water from oil

BENEFITS OF HEATING Viscosity Increased Differential Density Increased Film Strength Weakened Chemical Reactivity Accelerated

Heat Chemistry Flow Regime Coalescing Surfaces Electrostatic Fields

BENEFITS OF HEATING

Heating can cause problem for heavy oil

DRAWBACKS OF EXCESSIVE HEATINGFUEL COST LOSS OF VOLUME LOSS OF GRAVITY INCREASED MAINTENANCE SAFETY

CHEMICAL TREATMENT Chemical additives called demulsifiers are typically injected into the crude oil stream to weaken the stabilizing film surrounding the water droplets


Chemical TreatmentRequirements: Deactivate Natural Surfactants Enhance Condensation of Interface Zone Modify Wetting of Solids Produce No Insoluble By-Products

Major Components: Demulsifier (Primary Ingredient) Wetting Agent (Used if solids are a problem)

Selection Methods for Demulsifiers Bottle Tests Most Common Method Measure Sedimentation Rate Estimate Resultant Oil Quality Vary Chemical Type and Dosage Electrostatic Bench Tests Measure Response of Emulsion to Electrostatic Field: Power Requirements & Sedimentation Rate Measure Resultant Oil Quality Vary Chemical Type & Dosage and Electrostatic Field Type

Bottle Test

Chemical Dossage Mixing

100 cc Emulsion Heating to process temperature 24 hours settling evaluation

cc Oil

cc Emulsion

cc Water

t=0

t = t1

Chemical analysis: Electrical susceptibility test

Equipment for electrical susceptibility test


Graphical recorder

Test cell


Chemical analysis: Electrical susceptibility testAmperage against test temperature0.200 0.190 0.180 0.170

Amperage (mA)

0.160 0.150 0.140 0.130 0.120 0.110 0.100 0 10 20 30 40 50 60 70 80 90

Petrozuata Lagotreco Jusepn

Temperature (C)

Chemical analysis: Electrical susceptibilitytest0,0000205000 0,0000190000

Relative Electrical Conductivity against temperature

Electrical Conductivity (mA/V)

0,0000175000

0,0000160000

Petrozuata Lagotreco Jusepin

0,0000145000

0,0000130000

0,0000115000

0,0000100000 0 10 20 30 40 50 60 70 80 90

Temperatura (C)

Comparative Results 19.5API Brazilian CrudeChemical Bottle Test Water in Oil% By Difference

Electrostatic Bench Test BS&WMeasured %

A B C D E

2.2 4.6 5.3 5.7 6

2.12 2.01 1.62 1.20 2.35

Red: Best Performance

DEMULSIFIERSCHEMICAL TANK AND PUMP

TREATER

WET CRUDE INLET

DEMULSIFIER IS INJECTED UPSTREAM OF THE TREATER

FLOW DISTRIBUTION


Flow distribution is critical to achieving uniform velocity and avoiding excessive turbulence

FLOW DISTRIBUTIONCollector Outlet Distributed Flow

UP-FLOWDistributor

Inlet

LONGITUDINAL-FLOW

Perforated Distributor Baffles

COALESCING SURFACES CAN SPEED UP SEPARATION


ACHIEVABLE WATER REMOVALTREATED CRUDE BS&W (%)100 FREE WATER KNOCKOUT 3-PHASE SEPARATOR TREATER or DESALTER 0.1 10 20 30 40 50 70 100 CRUDE OIL GRAVITY (DEG API)

10

1

USING AN ELECTROSTATIC FIELD TO CAUSE COALESCENCE


+

-

POLARIZATION OF DISPERSED DROPLETS

+Dipoles Align With The Field Droplet Elongates

ELECTROSTATIC EFFECTS

DIPOLAR ATTRACTIVE FORCE BETWEEN EQUAL SIZED DROPS 2 6

F=

6 KE r 4 d

F = Force of Attraction = Dielectric Constant E = Electric Field Strength r = Drop Radius d = Interdrop Distance

Notice the Limitations: Very Sensitive to Drop Size Operates Over Short Range

Critical Voltage GradientMaximum Voltage at which Specified Drop Size Can Exist

Ec < ( / d )

1/ 2

y/x>1.9 y x Drop is polarized by the electrostatic field Drop is more conductive than continuum Drop deforms to a prolate spheroid Drop splits when ratio of axes becomes too large Electrical charge on the drop promotes shattering or

ELECTROSTATIC FIELDS

There are two basic types of electrostatic field:

AC FIELD DC FIELD. . . and several possible variations of each

DROPLET BEHAVIOR IN AN AC FIELD

+

-

+

-

OPPOSITE POLES OF POLARIZED WATER DROPLETS ATTRACT, PROMOTING COALESCENCE

ELECTROSTATICALLY INDUCED FILM RUPTURE Absence of Electric Field Surface Stabilized by Film Coalescence Inhibited Drop Stretched by Field Surface Film Broken Coalescence Enhanced

AC -TYPE ELECTRODESTRANSFORMER OIL OUT

WATER OUT OIL IN

AC FIELD BENEFITS DIPOLAR ATTRACTION FILM STRETCHING WATER TOLERANCE

BUT THERE ARE LIMITATIONS MINIMAL DROP MOVEMENT LOW CHARGE DENSITY LIMITS ON USEFUL FIELD STRENGTH

DROPLET BEHAVIOR IN A DC FIELD

+ +Electrodes

+ Upward oil flow

-+

A single small water droplet

COALESCENCE IN A DC FIELD

+

-

+ -

- + UPWARD OIL FLOW

- +

COALESCING IN A DC FIELDOpposites Attract

DC FIELD BENEFITSMOST AC FIELD BENEFITS, PLUS . . . DROPLET TRANSPORT NET ELECTROSTATIC CHARGE BUT. . . MUST AVOID ELECTROLYTIC REACTIONS WATER TOLERANCE IS REDUCED

ELECTROSTATIC FIELDS: DUAL POLARITY

AC/DC (DUAL POLARITY) COALESCER

PLATE ELECTRODE ARRAY

INSULATOR HANGERS RAILS

ELECTRODE PLATES

DUAL POLARITYProvides Combined AC/DC Fields For Combined Benefits Drop Polarization Film Rupture Water Tolerance Drop Movement Drop Charge Density Minimizes Induced Corrosion

TRANSLATING PROCESS INTO EQUIPMENT


PROCESS EQUIPMENT DESIGN

PROCESS EQUIPMENT DESIGNWe have looked at the the principles the industry utilizes to achieve crude oil dehydration. Different equipment suppliers apply these principles in different ways. Following is an overview of NATCOGROUP equipment design, using these principles.

FREE WATER KNOCKOUTGAS INLET

OIL

WATER

BATTERY OF VERTICAL TREATERS

VERTICAL TREATER (Cold climate options)INTERNAL FUNCTIONS DEGASSING MIST REMOVAL FREE WATER REMOVAL HEATING SECONDARY DEGASSING EMULSION COALESCING/SETTLING

TYPICAL TREATER FIRETUBE AND DRAFT SYSTEMSTACK HEAD TURBULATOR

STACK FIRETUBE AIR INTAKE/BURNER

CONE BOTTOM VERTICAL TREATEROPTIONAL ITEMS: CONE BOTTOM SAND JET RING HEATING BUNDLE SLOPED BAFFLES OUTSIDE LEVEL CONTROLS CROSS DRAIN

VFH TREATER (Vertical Flow Horizontal EQUALIZER GAS OUTLET Treater)INLET

OIL OUTLET

FIRETUBE FIRETUBE SHROUD FREE WATER OUTLET

SPREADERS

EMULSIFIED WATER OUTLET

FULL BAFFLE

PERFORMAX COALESCING PLATES

COALESCING SURFACESPERFORMAX MATRIX MATERIAL Polyvinylchlorid e Polypropylene Carbon Steel Stainless Steel

PERFORMAX TREATER (Horizontal Model)

DUAL POLARITY ELECTROSTATIC TREATER (VFH-CWW)

DUAL POLARITY ELECTROSTATIC TREATERS

SMALL OIL PRODUCTION BATTERY WITH SEPARATION AND TREATING

Dual Polarity Electrostatic Treater with Degasser

AC Field electrostatic dehydrators

Howe-Baker Electrostatic Dehydrators


Petreco Electrostatic Dehydrators


Kvaerner (HRI) Electrical treaters

Comparative suppliers analysisAC Field Proven technology in conventional desalting process Electrostatic dehydration/desalting under AC electric field Traditional desalting technology Lower comparative cost High oversizing design High sensitivity to emulsion tightness (high stability) and high water content High desalting multiple stages requirements Good technical support High control requirements

Dual Polarity Proven technology in conventional desalting process Electrostatic dehydration/desalting under Dual polarity (AC/DC) electric field and electrodynamic desalting process (exclusive technologies) Improved desalting technologies Higher comparative cost Optimal design (low oversizing) Low sensitivity to emulsion tightness (high stability) and high water content Low desalting multiple stages requirements Excelent technical support High control requirements

ELECTROMAX TREATER

ELECTROMAX CRUDE OIL DEHYDRATORCombines Electrical and Mechanical Coalescence High Flux Electrical Section Downflow Sedimentation Performax Mechanical Coalescer Dual Polarity Electrostatic Field Programmable Voltage Cycle Composite Electrodes Field Proven on Heavy and Difficult Oils

DUAL POLARITYTM DEHYDRATOR

TYPICAL ELECTRICAL ASSEMBLY

TECHNOLOGY

Following are some recent technology advancements that have significantly improved dehydration equipment performance.

Several Factors Influence Hydrodynamic Design of Separators Inlet nozzle and momentum breaker design critical to efficient use of vessel volume Internal baffle positions improve flow distribution and prevent high fluid velocity paths Discharge nozzle designs affect fluid quality (vortex breakers may be inadequate) Computational Fluid Dynamics Provides Insight to Fluid Flow in Separators

Velocity Vectors Colored by Velocity Magnitude

Computational Fluid Dynamics State-of-the-Art Method to Solve Practical Problems

Complex Fluid Flow Analysis

Flow Visualization and Distribution Analysis

Key Separator Components for Control of Fluid Flow Patterns Inlet nozzle geometry and location Momentum dissipation devices (e.g., splash plate, vortex tubes, ) Solid (non-porous) weirs and dams Perforated plates Outlet nozzle geometry and location Vortex breakers or other directional flow devices

TIME

Box-Type Spreader with Open Bottom00 SECONDS

TIME


TIME


TIME


TIME


TIME


TIME


TIME


TIME


TIME


TIME


Perforated Plates in Separators Establish good fluid flow distribution to reduce short circuiting Control liquid sloshing for ship-mounted systems

Perforated Plates in SeparatorsDesign Criteria Fraction of open area as holes Hole size Hole pattern Open area under plate for sand migration Placement and number of plates within separator

Fluid Flow Paths Upstream and Downstream of a Perforated Plate Show Turbulence and Recirculation Patterns

Dual Perforated Plates Redistribute Flow Down Length of Separator

Separators on Floating Platforms are Subjected to Six Degrees of Motion4 5 61. Surge: Y 2. Sway: X 3. Heave: Z

3 1 24. Pitch: ZY 5. Roll: ZX

6. Yaw: XY

For CFD Simulation, Vessels Placed in Actual Position on Platform to Accurately Capture Vessel Movement Due to Wave Motion

Iso-surface Plot of Water/Oil Interface (Case #1) Iso-surface Plot of Water/Oil Interface (Case #1)

Spill-over due to Roll Motion

Time = 28.0 sec

Vessel Tail

Top of Weir Plate w/ Lip

Water Spill-over Reaches The Oil Outlet

Advanced Technology Reduces the Size of Downstream Separation Equipment Electrostatic treaters dehydrate crude oil in ever decreasing vessel sizes CFD provides insight to vessel hydrodynamics Vessel internals designed to cope with process upsets Water Treatment Systems become smaller, more efficient Improved designs for hydrocyclones extend turn-down range and remove smaller droplets CFD-assisted column flotation design improves IGF performance Can move IGF off-platform to save weight & space

SHROUDED-PIPE SPREADERPatented Shrouded Pipe Distributor Excellent momentum absorption Near perfect flow distribution No more than 5% flow recirculation

U.S. Patent 6,010,634

ELAPSED TIME = 30 SECONDS

MODEL RESULTS - Water Table w/ DyeOUTLET

STANDARD PIPE DISTRIBUTOR INTERFACE

SHROUDED PIPE DISTRIBUTOR

MODEL RESULTS - Water Table w/ DyeELAPSED TIME = 60 SECONDS

STANDARD PIPE DISTRIBUTOR

SHROUDED PIPE DISTRIBUTOR

Shrouded Inlet SpreaderTIME 00 SECONDS












Effects of Arcing Arcing is a Natural Part of the Process Arcs Momentarily Discharge a Steel Electrode Array Significant Arcing Results in Performance Loss Due to Compromise of the Field

A Means of Arc Control is Needed.

COMPOSITE ELECTRODES

Conventional electrodes are constructed of Steel. Composite Electrodes are made of plastic


+

-

+

-

CONDUCTIVE STRIP

PLASTIC PLATE


CONDUCTIVE STRIP TAPERED VOLTAGE FIELD

COMPOSITE ELECTRODES PROVIDE ADDITIONAL TOLERANCE FOR WATER AND CONDUCTIVITY FIBER REINFORCED THERMOPLASTIC CONSTRUCTION RELIANCE ON SURFACE CONDUCTIVITY QUENCH ELECTRICAL ARCS PROVIDE FIELD GRADIENT INCREASE INTENSE-FIELD RETENTION TIME PROVIDE HIGHLY STABILIZED ARRAY

LOAD-RESPONSIVE CONTROLLERPOWER SUPPLY REQUIREMENTS PROTECTION MUST PROTECT ELECTRICAL COMPONENTS IN CONDUCTIVE ENVIRONMENTS FLEXIBILITY ABILITY TO HANDLE VARYING FEEDSTOCK AVAILABILITY MINIMAL DOWNTIME IN CHALLENGING CONDITIONS

LOAD-RESPONSIVE CONTROLLERConventional means of transformer protection: reactor in primary circuitR SF O TO R M C EA ER

POWER SUPPLY

TR

R

A

HI VOLTAGE TO PROCESS

N

LOAD RESPONSIVE CONTROLLERAnother way to control power time-based voltage chopping

Voltage

Crude Oil Conductivity Maintains Heat Dissipation Rating Functions During Process Upset Condition Preserves Coalescing Effect Microprocessor design allows field modulation

Slow Modulation Voltage Cycle

Field Control by Load Responsive Controller (LRC)

Modulated Dual Polarity Benefits

Modulation offers the Following Improvements:Added Coalescing Power More Effective on Smaller Drops Better Drop Growth Higher Water Tolerance Increased Tolerance to Conductive Oils

Modulated Fields - Terminology Threshold Voltage Gradient Voltage Gradient Necessary to Initiate Coalescence Critical Voltage Gradient Limiting Maximum Voltage Gradient at Which a Drop of a Specified Diameter Can Exist Modulation Frequency Affects Drop Transport Drop Relaxation Field Decay

State-of-the-Art Technology: Modulation of the Electrostatic Field

Slow Speed Modulation (as in EDD) Used to Control Drop Size Distribution Pulse Modulation Used to Energize Drop Surfaces Base Frequency Control Used to Limit Field Decay

Effects of Pulse Modulation & Base Frequency

Energizes Drops at Resonant Frequency Deformed Drops More Readily Coalesced Allows Adjustment for Physical Parameters Interfacial Tension (Pulse Modulation) Oil Conductivity (Base Frequency) Density Viscosity

Resonant Frequency Oscillation High frequency electrostatic field applied Marangoni Effect produces localized circulation in drop

Electrophoretic movement becomes oscillatory Drop deforms Surface free energy counters interfacial tension Drop surface becomes highly reactive Coalescence enhanced by reduced energy barrier

Field Decay in Conductive OilsLimits Coalescence Performance

+

VoltageIncreasing Conductivity

Effect of Base Frequency on Voltage DecayIncreases Coalescence Performance

1

1

sin ( z )

s i nz ) (

1 0 z 20

1 0 z 20

Low FrequencyNote deep RC discharge between voltage peaks.

High FrequencyNote shallow RC discharge between voltage peaks.

Low FrequencyNote deep RC discharge between voltage peaks.

High FrequencyNote shallow RC discharge between voltage peaks.

EXAMPLE OF IMPROVED TECHNOLOGY BENEFITPROBLEM: Increased capacity was needed through existing desalting units in Africa, and shipping quality specifications had to be maintained. SOLUTION: AC Treaters were Retrofitted with Dual Polarity Electrode system. RESULTS: Capacity increased from 50,000 BPD to 100,000 BPD and shipping quality was maintained.

EXAMPLE OF IMPROVED TECHNOLOGY BENEFITPROBLEM: Existing North Sea DUAL POLARITY dehydrator designed for 60,000 BPD, but production had increased to 100,000 BPD SOLUTION: Retrofit unit with Composite electrodes Retrofit unit with Pipe/Deflector spreader RESULT: Capacity increased to 100,000 BPD

DEHYDRATION DESALTINGCRUDE OIL

CRUDE OIL

THE SALT PROBLEMMineral salts are often carried in solution in the water which is emulsified in the oil. In addition there are often small amounts of insoluble solids carried in the oil or water phases. OILSALT IN WATER

THE SALT PROBLEMWHERE DOES THE SALT COME FROM? IN THE FIELD, IT COMES FROM THE FORMATION IN THE REFINERY IT IS EITHER RESIDUAL SALT REMAINING AFTER FIELD DEHYDRATION, OR IS SEA WATER WHICH HAS CONTAMINATED THE OIL

THE SALT PROBLEMTHE RESIDUAL WATER CONTAINS MINERAL SALTS. SALT IS A PROBLEM IN THE FOLLOWING WAYS . . . 1. IT PROMOTES CORROSION 2. IT FOULS HEATERS, HEAT EXCHANGERS, PUMPS AND TOWER TRAYS 3. IT POISONS CATALYSTS IN REFINERY UPGRADING PROCESSES

THE SALT PROBLEMTYPICAL SALT-IN-OIL REQUIREMENTS

FORCORROSION SALT DEPOSIT FOULING CORROSION SALT DEPOSIT FOULING CATALYST POISONING

OILFIELD: 10 - 25 PTB REFINERY: 0.5 - 3 PTB

(PTB = pounds of salt per 1000 bbls of oil)

THE SALT PROBLEM

THE SALT PROBLEM

S/O =

0.35 x S/W x W/L 1 - W/L

S/O = salt-to-oil (PTB) S/W = salt-to-water (mg/l water salinity) W/L = water-to-total liquid (volume fraction)

THE SALT PROBLEMDEHYDRATION ALONE IS INSUFFICIENT TO MEET THE SALT REMOVAL REQUIREMENTS IN MANY CASESPTB (POUNDS OF SALT PER 1000 BBLS OF OIL)200g/ l 0 m ,0 0

20 0

100

.00 0 10

g/l 0m

/l 0 mg 0 50,0

TYPICAL FIELD REQUIREMENTS TYPICAL REFINERY REQUIREMENTS

0

0.1

0.2 0.3 0.4 0.5 RESIDUAL WATER (%)

0.6

DESALTING FUNDAMENTALS0.35 x S/W x W/L 1 - W/L

S/O =

This formula suggests that there are two parameters that determine salt-in-oil: Water Salinity Water Fraction of the Stream

DESALTING FUNDAMENTALSWater fraction can be reduced by simple dehydration, using principles already discussed. To reduce water salinity, it must be diluted.

+

=

DESALTING FUNDAMENTALS Basic desalting consists of two sub-processes: 1st - Dilution - of the dispersed brinewith a water of lesser salinity (called wash water or dilution water)

2nd - Dehydration - removal of the diluteddispersed brine by oil dehydration

DILUTION OF DISPERSED BRINEDesalting Chemical injection Wet Crude Oil Inlet To desalter vessel for dehydration

Wash water Injection

Mixing by Continued Rough hydraulic or hydraulic Dispersing mechanical Coalescence of wash agitation, water usually a Mixing Valve

THE MIXING VALVEDifferential Pressure Controller DPC

To Desalter Crude Flow Mixing Valve Static Mixer (Optional) is occasionally installed either upstream or downstream of the mixing valve

MIXING VS. DEHYDRATION IN DESALTING

DESALTER BASIC FLOW SCHEMEDesalted Oil Discharge

Single Stage Desalter

Crude Oil Inlet Wash Water Inlet

Mix Valve

Brine Discharge

CONSERVATION OF WASH WATERThere are several reasons why wash water must be conserved: Supply of fresh or near-fresh water is often scarce, particularly in the producing field. Disposal of effluent water is often costly, and needs to be minimized. Too much total water can cause desalter electrodes to short-circuit.

SOURCES OF WASH WATERRefinery Condensate from towers Cooling water Utility water Field Deep fresh-water formations Shallow groundwater River water Sea water (often must be de-salinated)

DUAL POLARITY DESALTER (typical)

DOUBLE VOLT AC ELECTROSTATIC COALESCERPower Unit 1Phase A Phase B Earth

Power Unit 2Phase B Phase C Earth

Power Unit 3Phase C Phase A Earth

Grid 1

Grid 2

Grid 3

Earth

Power Unit Primary ConnectionsDELTAPower Unit 3

Grid ConnectionsPower Unit 1

Power Unit Secondary ConnectionsGrid 1Power Unit 1 Power Unit 2

Phase APower Unit 1

Grid 1 DELTA STARPower Unit 3

Phase B Phase CPower Unit 2

Grid 3Power Unit 3

Grid 2Power Unit 2

Grid 3 Earth

Grid 2

TRIGRID AC ELECTROSTATIC COALESCERPower UnitPhase A Phase B Earth

Grid 1 Earth Grid Grid 2

Earth

Power Unit Primary ConnectionsPhase A

Grid ConnectionsPower Unit Grid 1

Power Unit Secondary ConnectionsEarth

Phase B Grid 2 Earth Grid 1 Grid 2

TRIVOLT AC ELECTROSTATIC COALESCERPower Unit 1Phase A Phase B Earth

Power Unit 2Phase B Phase C Earth

Power Unit 3Earth Phase C Phase A

Grid 1

Grid 2

Grid 3

Earth

Power Unit Primary Connections

Grid ConnectionsPower Unit 1 Power Unit 2 Power Unit 3

Power Unit Secondary ConnectionsGrid 1

Phase APower Unit 1

DELTA

STAR Grid 1Power Unit 2

Power Unit 1 Power Unit 2

Phase B Phase C

Grid 2 Grid 3

Power Unit 3

Grid 3 Earth

Grid 2

HIGH VOLTAGE ASSEMBLYOverflow with liquid seal Oil Level Glass Disconnect Link High Pressure Bushing Continuous Vent 10 ANSI Class 300 lb Power Inlet nozzle Vessel Wall Power Connector Rod Weight Pick-up bucket

Power Unit

Electrode Insulator Assembly

DESALTER SIZINGFLOW

OIL FLOW (BPD) AREA = DESIGN FLUXDESIGN FLUX OBTAINED FROM...

DESIGN FLOW AREA

SIZING STANDARDS LOCAL HISTORICAL NORMS PILOT TESTS

PILOT TESTSNatcos HTU dehydration/desalting pilot unit in the Tulsa R&D facility simulates field or refinery dehydration and desalting processes; tests conventional and state-of-the-art technologies

PILOT TESTS

LIMITATIONS OF SINGLE STAGE DESALTERS

To maintain reasonable wash water requirements, the inlet stream can contain only a small amount of dispersed brine. To reduce high inlet brine concentrations, a dehydrator is placed upstream.

DEHYDRATOR/DESALTER FLOW SCHEMEOutlet Oil

Emulsion Inlet Effluent Water Wash Water Mix Valve EffluentWater

TWO STAGE DESALTERS

WITH INTER-STAGE RECYCLE

Brine Recycle

THREE STAGE DESALTERS WITH INTER-STAGE RECYCLEWhere extreme wash water conservation or deeper desalting is required, three stages may be used

INTERNAL RECYCLESingle Stage Desalter with Internal RecycleDesalted Oil Discharge

Crude Oil Inlet

Mix Valve Internal Recycle

Recycle Pump Brine Discharge

Wash Water Inlet

INTERNAL RECYCLETwo Stage Desalters with Internal and Inter-Stage RecycleFirst Stage Second Stage Desalted Oil Discharge

Crude Oil Inlet

Mix Valve

Mix Valve

Recycle Pump

Inter-Stage Recycle Brine Discharge Wash Water Inlet Internal Recycle

INTERNAL RECYCLEThree Stage Desalters with Internal and Inter-Stage RecycleFirst Stage Crude Oil Inlet Second Stage Third Stage Oil Discharge

Brine Discharge

Wash Water Inlet

REFINERY DESALTING

PRODUCER A

PRODUCER C

REFINERY

PRODUCER B PRODUCER D

FIELD DESALTERS(3) 2-Stage Trains At Sea Side, Egypt

FIELD DESALTERS

1st and 2nd Stages, Mid-East

REFINERY DESALTERS

2-STAGE, Mid-East

DESIGN AND OPERATIONAL CONSIDERATIONSSEPARATION OF SUSPENDED SOLIDS CHEMICAL TREATMENT WATER WASH REMOVAL OF SEPARATED SOLIDS SAND JETS (MUD WASH SYSTEM) INTERFACE SLUDGE DRAINS

DESIGN AND OPERATIONAL CONSIDERATIONSAVOID CRYSTALLINE SALT In the producing field, it is caused by low watercontent wells being flashstripped during degassing. In the refinery it is caused by heating a low watercontent crude to where the water solubility exceeds available water.

AVOIDING SALT CRYSTALLIZATION AND DEPOSITION IN REFINERY DESALTERSFEEDSTOCK TANKS CHARGE PUMPS HEATERS DESALTERS

SMALL AMOUNT OF WASH WATER INJECTED UPSTREAM OF HEATERS

WASH WATER SUPPLY

Solids Control Sources of Solids Formation Fines & Precipitated Scale Precipitated Asphaltenes Solids Partitioned Between Oil and Water Phases Chemical Treatment May Help Some Remain in the Vessel Interface Sludge Bottom Sediments Removal Is Essential For: Control of Conductivity Maintenance of Flow Distribution

Solids Removal

Interface Sludge DrainOperated As Required

Mud Wash (Sand Jet) SystemScheduled Operation

TECHNOLOGY

ADVANCED DESALTING TECHNOLOGIE S

ELECTRO-DYNAMIC DESALTER

Combines 5 Essential Process Technologies: Dual Polarity Electrostatic Dehydrator Start with a proven technology Composite Plate Electrodes Provide high water tolerance Load Responsive Controller Controls field strength Counterflow Dilution Water Process Provides multi-stage contact Electrostatic Mixing Process Focuses mixing energy only on dispersed phase


ELECTRO-DYNAMIC DESALTERWASH WATER INLET OUTLETOIL COLLECTOR

WASH WATER HEADER

...................................COMPOSITE ELECTRODES SPREADER

INLET

WATER OUTLET

ELECTRO-DYNAMIC DESALTER - LOAD RESPONSIVECONTROLLER

ELECTRO-DYNAMIC DESALTER PC BASED LOAD RESPONSIVE CONTROLLER LOCAL MAY BE LOCALOR REMOTE Transformer, SCRs and Firing Board Diodes NATCO Control Board and Diagnostic Display Junction Box DEDICATED OR PORTABLE PC With LRC Program and Monitoring Software

Control Feedback AC Power

LRC Control Software

LRC Programming/ Monitoring Software3

ELECTRO-DYNAMIC DESALTER COUNTERFLOW WASH WATER PROCESS

ELECTRODE PLATES

WASH WATER HEADER DOWNWARD WATER FLOW

UPWARD OIL FLOW


TYPICAL SINGLE STAGE EDDCOUNTERFLOW WASH WATER INLET

OIL OUTLET

CRUDE OIL INLET FIRST WASH WATER INLET MIX VALVE

BRINE OUTLET

EDD IN FAR EAST REFINERY



Dual Frequency Technology Transformer Three phase design Low reactance Increases power utilization up to 70%.

Voltage Control Voltage levels can be optimized. Pulse waveform can be selected.

Frequency Control Base Frequency Pulse Frequency

Dual FrequencyCompact Electrostatic Dehydrator Modulation of the Electrostatic Field Slow Speed Modulation Used to Control Drop Size Distribution High Speed Modulation Used to Energize Drop Surfaces

Dual FrequencyCompact Electrostatic Dehydrator High Speed Modulation of Field

Energizes Drops at Resonant Frequency Deformed Drops More Readily Coalesced Allows Adjustment for Physical Parameters Interfacial Tension Oil Conductivity Density Viscosity

Dual FrequencyCompact Electrostatic DehydratorBenefits: Incremental improvement, over existing best in class electrostatic technology. Allows the operator to minimize planned capital expansions: Increases processing capacity of existing vessels. Allows processing of difficult, highly conductive, viscous oils and/or oil blends. Debottleneck offshore platforms where minimization of space, weight and performance are critical.

Dual FrequencyCompact Electrostatic DehydratorCharacteristics:The transformer consists of three primary components, packaged in a single oil-filled enclosure (three phase, 480 volts (50 / 60 Hz)). First, the 480 volts is conditioned to produce a variable amplitude and variable frequency voltage supply for the primary of the transformer. Second, the medium frequency transformer steps up the input voltage to a secondary voltage level necessary to promote effective coalescence. Third, the secondary voltage is rectified into positive and negative half-wave outputs. These polarized, half-wave voltages are then applied to the electrodes to create the benefits of both AC and DC fields.

Dual FrequencyCompact Electrostatic DehydratorA PC-based process controller defines the voltage production. To highly conductive crude oils: Increasing frequency to maximize the energy delivered to the oil dehydration process. Using a medium frequency transformer overcomes the voltage decay associated with conventional 50/60 Hz transformers. Where the interfacial tension between the oil and water is low: Adjust the waveform minimize destruction of the water droplets normally caused by the application of 50/60 Hz power. Reducing the frequency of the waveform and the selection of the shape of the voltage waveform allow to achieve the best dehydration results.

Dual FrequencyCompact Electrostatic Dehydrator In wet crude oils (low effective impedance, rapid voltage decay): Reduces voltage decay and effectively sustains the applied voltage. Seting the minimum and maximum voltage levels to increase the percentage of the entrained water that is swept by the electrostatic voltage. Maximize the droplet growth to promote a rapid sedimentation rate and reach the smallest water to develop a surface charge and promote coalescence. Reducing the voltage to a minimum level will maximize the droplet growth to promote a rapid sedimentation rate.

Dual FrequencyCompact Electrostatic DehydratorPC-based Dual Frequency load responsive control system can control:

The output of the transformer to produce an infinite variety of waveform configurations. The unique waveform generated is optimized to the specific oils physical properties, and enables higher treatment rates and lower BS&W levels than conventional technology.

Demulsification vs. FrequencyDemulsification, % 100 80 60 40 20 0 0 500 1000 1500 2000 Frequency, Hz 1000 V 3000 V

Data from German Researchers

International Chemical Engineering, Vol. 33, no. 1, January, 1993

Dual FrequencyThe Latest Development

Combines Modulation Modes Maximum Drop Growth & Vessel Flux Optimized for Crude Oil Characteristics More Efficient Power Utilization Easy Retrofit

Dual Frequency Field Test Results

0.5

0.4

Outlet BS&W (%)

0.3

0.2

0.1

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P

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m Co y

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0 0 20000 40000 60000 80000 100000 120000

Capacity (BOPD)

Dual Frequency Results

Dual Frequency Applications

Retrofits to existing installations: Especially Dual Polarity (External Changes) Increased performance: BS&W and/or Capacity

Refinery market where: Highly conductive crudes cannot be desalted Space is a constraint

Offshore production facilities where: Space is limited Weight increases deck construction & expense

Dual Frequency Advantages Reduced outlet BS&W by 30 to 95% Tested on oils between 17 & 40 API.

Allows an increase in vessel throughput from 50 to 100%. Easy retrofit to existing Dual Polarity dehydrators or desalters Estimated 2000 vessels currently in service.

Replaces steel and vessel volume with advanced electrostatic controls Easily optimized to process conditions.

Dual FrequencyCompact Electrostatic Dehydrator

Dual Frequency TM Compact Coalescer Technology

Conventional A/C 14 x 65

Current State-of-the-Art Technology 12 x 40

Dual FrequencyTM 10 x 26

Coalescing Droplets

Example: 80,000 BOPD 32 API Crude 4 cps Viscosity Inlet: 5% BS&W Outlet: 0.5% BS&W

electrostatics separation technology

Documents

oil emulsion

oil solubilities typical

crude oil stream

crude oil treating

separation of emulsified

mechanism of oil dehydration

crude oil production

t1 chemical analysis