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SURFACE PROCESSING
A – CRUDE OIL TREATMENT
I- SEPARATION
©2007
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SEPARATION – Contents
1- Well effluents Generalities
2- Gas/liquid separation
-equilibrium calculations
-influence of the process recovery rate
3- Separator sizing principles
-diphasic vertical separator
-diphasic horizontal separator
4- Gas/Liquid Separator different types
5- Foaming (difficult gas/liquid separation)
Next course: Oil/Water separation
©2007
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1- Well head effluents
©2007
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WELL HEAD EFFLUENTS
WELLHEADWELLHEADEFFLUENTSEFFLUENTS
GASGAS
OILOIL
WATERWATER
FORMATION SAND AND SILTFORMATION SAND AND SILT
COLLOID STATE CLAYCOLLOID STATE CLAY
CORROSION PRODUCTCORROSION PRODUCT
WAXESWAXES
ASPHALTENESASPHALTENES
MINERAL CRYSTALSMINERAL CRYSTALS
NaClNaCl CaCO3 BaSO4 SrSO4CaCO3 BaSO4 SrSO4
©2007
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SEPARATION CHAIN
EMULSIONEMULSION
INTERMINGLED WATER/OILINTERMINGLED WATER/OIL
FOAMSFOAMSLIQUID DROPLETS LIQUID DROPLETS
IN GASIN GASWELLHEAD EFFLUENTSWELLHEAD EFFLUENTS
CONDENSATECONDENSATE
FREE WATERFREE WATER
GASGAS--LIQUIDLIQUID
SEPARATIONSEPARATION
GAS TREATMENTGAS TREATMENT
DEHYDRATIONDEHYDRATION
CONDENSATE CONDENSATE
RECUPERATIONRECUPERATION
EMULSIONEMULSION
TREATMENTTREATMENT
WATERWATER
EMULSIONEMULSION
GASGAS
WATERWATER
OPERATIONS SOMETIMESOPERATIONS SOMETIMESCARRIED OUTCARRIED OUT
in 1 PROCESS EQUIPMENTin 1 PROCESS EQUIPMENT
export
crude
OILOIL--WATERWATER
SEPARATIONSEPARATION
©2007
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SOURCE OF WATER
WATER AND OIL ZONES IN RESERVOIR WATER AND OIL ZONES IN RESERVOIR
OILOIL
OILOIL
* Active Water Reservoir* Active Water Reservoir
* Water Injection : Injection of 1* Water Injection : Injection of 1--2 volumes of water2 volumes of water
Production of 1Production of 1--5 volumes of water per oil volume5 volumes of water per oil volume
* Faulty Cementing Job* Faulty Cementing Job
©2007
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SOURCE OF SALT
SALTSALT
RESERVOIR WATERRESERVOIR WATER
INJECTED WATER (SEA WATER)INJECTED WATER (SEA WATER)
*If Salt Content>10mg/l , Reservoir Water INGRESS*If Salt Content>10mg/l , Reservoir Water INGRESS
Produced Water Not Detected; only salt content is measured Produced Water Not Detected; only salt content is measured
*HASSI MESSAOUD : CAMBRIEN WATER 370g/l*HASSI MESSAOUD : CAMBRIEN WATER 370g/l
Low Water CutLow Water Cut HIGH SALT CONTENTHIGH SALT CONTENT
0,1%0,1% SALT CONTENT 370 mg/lSALT CONTENT 370 mg/l
*Sometimes HIGH SALT CONTENT without WaterEAST BAGDAD As much as 265ppm of salt ***
* Same for Hassi Messaoud - Fateh - ABK -ZadcoThis Phenomenon is limited in Time
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OIL , BSW and GOR EVOLUTION WITH TIME
Production
106 m3 / an3
2
1
GORGOR
OILOIL
BSW
%
3030
2020
1010
300300
200200
100100
YEARS
BSWBSW
11 22 33 44 55 66 77 88 99 1010 1111 1212
GOR
���� difficulty to design separation equipment
©2007
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CONTRACTUAL WATER AND SALT CONTENTS
TRANSPORTERSTRANSPORTERS : LIMITATION FOR WATER CONTENT: LIMITATION FOR WATER CONTENT
*PIPELINE *PIPELINE -- PIPE OVER LOADINGPIPE OVER LOADING
BSW <= 0.5%BSW <= 0.5%
-- CORROSION ( WATER + SALT )CORROSION ( WATER + SALT )
*BY SEA NO FIXED CONSTRAINTS*BY SEA NO FIXED CONSTRAINTS BUTBUT
-- ACCIDENTAL CONTAMINATIONACCIDENTAL CONTAMINATION
-- LOAD ON TOP CONTAMINATIONLOAD ON TOP CONTAMINATION
AGREEMENTAGREEMENT
PRODUCERSPRODUCERS
TRANSPORTERSTRANSPORTERS
REFINERSREFINERS
CRUDE OIL MARKETINGBusiness is
business!!$$
©2007
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1 ELECTROSTATIC DESALTER1 ELECTROSTATIC DESALTER SALT CONTENT <5mg/lSALT CONTENT <5mg/l
* SCALE DEPOSIT INSIDE EXCHANGERS* SCALE DEPOSIT INSIDE EXCHANGERS
* DISTILLATION UNITS CORROSION
* RESIDUAL QUALITY DEGRADATION* RESIDUAL QUALITY DEGRADATION
95 % EFFICIENCY 95 % EFFICIENCY INLET SALT CONTENT < 100 mg/l INLET SALT CONTENT < 100 mg/l INLET SALT CONTENT < 100 mg/l
EUROPEAN REFINERIES
REFINERY : Salt...100 mg/lREFINERY : Salt...100 mg/l Water....0,2%Water....0,2%
TRANSPORT : Salt...60 mg/lTRANSPORT : Salt...60 mg/l Water....0,5%Water....0,5%
BSW in Production Fields < 0.5 %BSW in Production Fields < 0.5 %BSW in Production Fields < 0.5 %
PRODUCTION FIELD SPECIFICATIONS
CONTRACTUAL WATER AND SALT CONTENTS
©2007
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DEHYDRATION
TO WITHDRAW WATER DISPERSED IN CRUDE STRESSINGTHE WATER CONTENT
DESALTING
TO GET THE SALT SPECIFICATION WHEN THIS IS NOT THEDIRECT RESULT OF COMPLYING THE WATER SPEC.
DESALTING IS A DEHYDRATION TRT SET PREVIOUSLY WITH WASH WATER SOFTERTHAN RESERVOIR WATER
DEHYDRATION/DESALTING
©2007
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DEHYDRATION/DESALTING
With Reservoir Water at 350 g/l expressed as NaCl equivalent
0.1 % of Water Content 350 mg/l ( 123 PTB ) Salt Content
Salt Content < 60 mg/l Water Content < 0.017 %
SALINITY IS THE MOST RESTRICTING SPECIFICATION
With Reservoir Water at 40 g/l expressed as NaCl equivalent
0.1 % of Water Content 40 mg/l ( 14 PTB ) Salt Content
Salt Content < 60 mg/l Water Content < 0.15 %
WATER CONTENT IS THE MOST RESTRICTING SPEC.
©2007
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2- Gas/liquid separation
©2007
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GAS/LIQUID SEPARATION - Generalities
Hydrocarbon reservoir :
at reservoir conditions, generally one monophasic fluid
at surface conditions (P &T decrease), different components appear :
monophasic � polyphasic (gas + liquid)
hydrocarbon gas � condensation of heavier hydrocarbons liquid
water vapour � liquid water
THERMODYNAMIC BEHAVIOUR
©2007
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TREATMENT UNIT
AIM OF A TREATMENT UNIT
to recover all the different constituents
� Process specific to each development
to treat oil so that it is free of gas
to produce a gas as dry as possible (no water nor heavy hydrocarbons)
to remove water (and solids) from oil
to remove oil and solids from water (�Water Treatment specific courses)
©2007
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Pr
Pw
Pf
Pc
Pr Reservoir
Ps
Storage Shipping
Separation
Hydrocarbon production scheme
Pr: Reservoir pressure
Pf: Bottomhole flowing
pressure
Pw: Wellhead pressure
Pc: Choke pressure
Ps: Processing pressure
©2007
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P T
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Phase diagram
P
Liquid
Pr
Vapour
T0
Pf
0 %
100 %
Ps
Pc
Pw
Bubble Point
mole % liquid
30 %
15 %5 % 1 %
©2007
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METHANE - ETHANE MIXTURE PHASE DIAGRAM
©2007
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GAS PHASE ENVELOPPE SHAPE VERSUS GAS COMPOSITION
©2007
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P T
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ingPRO01198 – CRUDE OIL TREATMENT - Separation
at Constant composition
1. Flash process
If T constant = flash liberation
P1 V1T1
P2 V2T2
with P1 > P2
P1 V1T1
P2 V2T1
P1 > P2
P1 V1T1
P2 V2T2
P1 > P2T1 > T2
If T varies = flash separation
G1L1
P1 T1
G2L2
P2 T2
©2007
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P T
rain
ingPRO01198 – CRUDE OIL TREATMENT - Separation
total composition varies : there is draw off
2. Differential process
If T = constant = differential liberation
P1 > P2
G1L1
G2L2
GiLi
GS
P1 T1 P2 T2
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P T
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3. Composite process : combination of the two
GL
LG1L1 L2
GSLS
G2
PG TG PF TG P1 T1 P2 T2 Pa Ta
DifferentialLiberation (T cst)
Flash Flash Flash
Reservoir Separators Storage
PG
PF
P1
P2
Pa
Ta T2 T1 TG
P
T
©2007
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OPTIMAL SEPARATION PRESSURE IN HYDROCARBON PRODUCTION
FIELDS IS AN APPLICATION OF PHASE EQUILIBRIUM IN
THERMODYNAMICS
�AMOUNT OF LIQUID RECOVERED IS DEPENDENT OF THE
COMPOSITE PROCESS
�SEPARATION EFFICIENCY
YIELD (R) = final stock tank oil mass / mass of hydrocarbons entering
the processing unit
©2007
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Influence of the Process Recovery rate
Separation
P
Pb
13
15° TGT
Liberation
2
1
Rs
P
Flash
Differential
Pb
Rs =V gas produced
V oil at Pb
FROM PVT LAB EXPERIMENTS
©2007
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QUANTITIES OF FREE GAS ARE MORE IMPORTANT IN FLASH
LIBERATION THAN IN DIFFERENTIAL LIBERATION
SIMILARLY, VOLUME OF LIQUID IS GREATER IN A DIFFERENTIAL
PROCESS THAN IN A FLASH PROCESS
THE RELATIVE DIFFERENCE BETWEEN THE TWO CURVES DEPENDS
ON THE NATURE OF THE OIL : SLIGHT FOR HEAVY OILS AND
GREATER FOR VOLATILE OILS
�the higher the number of separation stages, the greater the liquid
recovery
�but P at 1st stage is governed by well head P (i.e. reservoir P)
�number of stages is a compromise between costs of installation and
liquid recovery
Influence of the Process Recovery rate
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GL
GL
Pi T1 Ps T1
Flash liberation
max gas & min liquid
One stage
Application / Field
Several stages
P1 T1 P2 T1
L
P3 T1
L
Ps T1
G
Separators Storage
G
L L
G G
Influence of the process Recovery rate
in each separator : flash liberationbut the whole chain of separators represents a differential separationmax of liquid recovery for an infinite number of separation stages
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Rule of thumb
Separation pressure at the different stages
n = number of stages + storage
Examples
GOR < 20 m3/m3 1°: 3-7 bara2°: Storage
GOR < 150 m3/m3 1° :10-20 bara2°: 2-6 bara3°: Storage
P sep. HP
P storage
n - 1
R =
GOR > 200 1°: 20-40 bara
2°: 5-15 bara
3°: 2-5 bara
4°: Storage
©2007
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PALANCA FIELD (ANGOLA)
Separation efficiency = final stock tank oil mass / mass of hydrocarbons
entering the processing unit
at P = 25, 20, 15 & 10 bar
at T = 105°C, 90°C, 75°C
Determination of the optimal P & T and number of separation stages to get the
higher separation efficiency
EXAMPLE OF APPLICATION
©2007
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Sep. Efficiency (%)
74
73.5
73
72.50 10 20
105
Pressure (bars)
25
90
75° C
75
74.5
75.5
76
76.5
5 15
PALANCA separation – output 2nd stage
©2007
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Sep. Efficiency (%)
74.5
74
73.5
730 6 12
105
Pressure (bars)15
90
75° C
75.5
75
76
76.5
77
3 9
Low pressure separator pressure
77.5
PALANCA separation – output 3rd stage
©2007
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P T
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Sep. Efficiency (%)
75.5
75
74.50 6 12
105
Pressure (bars)
15
90
75° C
76.5
76
77
77.5
3 9
Medium pressure separator pressure
PALANCA separation – output 4th stage
©2007
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Pressure (bar)
Output (%)
76.5
76
75.50 10 20 25
4 stages
77.5
77
78
5 15
3 stages
2 stages
PALANCA separation – output T=75°C
significant gain
between 2 & 3
less gain between
3 & 4
���� ECONOMICS
COMPROMISE
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Influence of separation temperature
Temperature + -
Low
Average
High
• Liquid• Economy
• Water
• Gas• H2S treatment
• Gas
Price
EFFECT ON RECOVERY ( )
in general, the lower the T the higher the liquid recovery
(but other parameters interfere on final Process T chosen : e.g. oil/water separation
which is enhanced by high T°C)
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ASHTART
Gas
13b - 110 °C
1b - 85 °C
Gas
Oil
Gas
5b - 40 °C
1b - 35 °C
Gas
Oil
GAIN 9 % OIL at
lower T
Influence of separation T & P : example 1
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BREME
Flare
4b 40° C
1b
Gas
Oil
Flare
4b 40° C
1b
Gas
Oil
GAIN 2.6 % OIL
from flare gas recovery
3.5 b 30° C
Influence of separation T & P : example 2
©2007
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3- Separator sizing
©2007
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Sizing of a separator
INCREASING COMPLEXITY OF FIELD INSTALLATIONS WITH THE AIM
TO MAXIMISE RECOVEY AND OPTIMISE ALL PRODUCTION UNITS
INTRODUCTION TO GENERAL PRINCIPLES AND METHODS OF SIZING
AND TYPICAL VALUES
SPECIFIC INSTALLATIONS AS HEATER-TREATER, CYCLONIC
SEPARATORS, etc. ARE DETERMINED BY MANUFACTURERS
©2007
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Sizing of a separator
DIMENSIONS FOR GAS AND LIQUID FLOWRATES ARE CALCULATED
SEPARATELY
FOR GAS FLOWRATE, SPEED LIMITED TO PREVENT GAS FROM
ENTRAINING DROPLETS OF LIQUID ���� smallest diameter possible
FOR LIQUID FLOWRATE, RETENTION TIME ���� SIZE TO ENSURE THAT
THE GAS IS COMPLETELY RELEASED FROM IT
DEPENDS ON OIL CHARACTERISTICS
©2007
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Basic data
Sizing of a separator
Gas : Flow rate - composition - specific massOil : Flow rate - composition - specific massRetention time
1
Sizing for gas
Sizing = passage cross-sectionPassage cross-section = f (limit velocity gas)Limit velocity gas = liquid not drawn with it
2
Sizing for liquids
Sizing = f (retention time)Retention time = time needed for degassingRetention time = f (oil characteristics)
3
©2007
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Vertical separator GAS
Aim : PREVENT WATER BEING DRAWN ALONG
P
T
P =ΠΠΠΠD3
6 Lg
Condition : P > A + R
fixed D limit = 20 µm
A =ΠΠΠΠD3
6VgR = K
ΠΠΠΠD2
4V2
V
V < K D L - VV
1GOR
LV
) = m/sKv = f (
at
D (Ø)L
Liquid
VV (velocity)Gas
A R
P
Sizing of a separator
weight buoyancyaerodynamic force
liquid
max speed not
to carry over D
©2007
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Calculation of V (P and T) from M
• Let M = 30 (0° C - 1013 mb)
o =30
22.4Kg/m3 =
MPZRT
• If T = 50° C and P = 20 bar
V = o x PP0
x T0
Tx 1
Z
A few values of Kv
• Flare drum (horizontal) 0.04 m/s• Column head separator (horizontal) 0.07 m/s• Compressor suction (vertical) 0.04 m/s
=30
22.4 x20
1.013 x273323 x
10.93 = 24 kg/m3
Vertical separator GAS
Sizing of a separator
©2007
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Separator value of Kv in m/s versus GOR
©2007
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Vertical separator LIQUID
Transit time through the vessel
Concerns water and oil (Gas : pm)
T = VQ
= ΠΠΠΠ D2
4x h
Q
Sizing of a separator
T:transit time
T:transit time fonction of decantation time and retention time
©2007
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Gas Outlet
GAS
Oil outlet
Water outlet
OIL
WATER
Feed
Water droplet
Gas bubbleOil droplet
VERTICAL Separator / Liquid : liquid sizing
Decantation time refers to liquids
©2007
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Vertical separator LIQUID
Decantation time
STOKES' law
D=O.1 mm (around 20 to 30 µm in general)
V =g D2 ( L - V)
18 µµµµ
Sizing of a separator
V = settling velocity of the liquid dropletD = diameter of the dropletL = specific gravity of dropletV = specific gravity of the gas at P&T
g = gravitational accelerationµ = viscosity of the continuous phase
note : Decantation time is very dependant of the crude and water characteristics (���� emulsions)
©2007
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Vertical separator LIQUID
Retention time (practical reference)
Sizing of a separator
corresponds to the value obtained by taking the volume measured between the mean level and the low level, where the mean level usually is located in the middle of the drum
Often varies with the crudes from 2" to 5" in most casesbut can reach 10" or even 30" or 60" for "problematic" crude, i.e. heavy oils or acid crudes
©2007
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Vertical separator
• Gas passage velocity :
V critical = 0.048 in m/s
Common practices
L - GG
• Internal diameter :D =
D in mQ in m3/hV in m/s
Q
900. ΠΠΠΠ . V• Height of separator :1.5 < Height/Diameter < 3
• Max. oil level :Hoil < 0.65 D
• Low oil level :at 10 inches from the bottom
• Retention timeOil + water = 2" to 5"If foaming or high viscosity : 10"(heavy oil ROSPO MARE : 35")
Sizing of a separator
©2007
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Horizontal separator
Sizing of a separator
DemisterFlow straightened cross section
Gas
Liquids
Secondary chamber
Decantation chamber
AR
Pliquid
Horizontal separator
Gravity Gravity
Vertical separator
Resultant
Entrainment Entrainment
ResultantKv horiz. = 1.25 Kv vertical
©2007
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L
l
Vhh
D
Water
h = continuous water height (water)
vh = decantation velocity of an oil droplet (rising)
vwater = displacement velocity of the continuous water phase (horizontal)
l = minimum decantation length
t = decantation time.
Oil droplet Vwater
Horizontal separator
Sizing of a separator
Decantation time
with Stokes law
©2007
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Sizing of a separator: Summary
GAS IS THE PRIORITY PARAMETER TAKEN INTO ACCOUNT IN THE
DESIGN OF SEPARATORS
LIQUID TRANSIT TIME (often referred as Retention time) IS MORE
EMPIRIC AND IS MORE BASED ON EXPERIENCE WITH SAFETY
MARGINS MORE OR LESS IMPORTANT
DECANTATION TIME FOR LIQUIDS IS GENERALLY BASED ON LAB
EXPERIMENTS
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4- Gas/Liquid Separator different types
©2007
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Vertical 2 phase separator
Drainage duct
Pressure
valve
Safety seal
Mistextractor
Pressure gauge
Déflector
Oil andgas inlet
Primarychamber
Visuallevel
monitor
Decantationchamber
Base
Purge
Oil outlet
Manhole
Isolation partition
Centrifugal effectin a vertical separator
Gas flowLiquid flow
3
2
1
1. body of separator
2. gas outlet (high point)
3. fluid input
Deflector action
well adapted
for low GOR
©2007
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Horizontal 2 phase separator
Mist extractorSettlingsection
Secondarychamber
Primarychamber
Diffuser
Gas + liquidsinlet
Decantationchamber
Separationpartition
Purge
Anti-wavepartition
ChassisOil outlet
Gas
Liquid
Inlet diffuser
Gas
outlet
well adapted
for high GOR
©2007
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gas outlet Inlet
liquid outlet
High-pressure horizontal separator with liquid retention capacity
large capacity
high P
©2007
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Spherical 2 phase separator
Fluids inlet
Gas outlet
Oil outlet
Level regulation
Scrubber
Deflector
rare
for very high GOR
©2007
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Cyclone effect separator
Gas outlet
Gas + Liquid inlet
Liquid outlet
©2007
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Multi-cyclone separator
Multi-cyclones
Gas outlet
Liquidoutlet
DiffuserGas inlet
Liquid level Secondary drain
Retention volume
Liquid outlet
©2007
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Other typesof gas/liquid separators
©2007
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Gas SCRUBBER
Mist extractor
Sifter
©2007
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VAPE SORBER
Absorbent material
Porous filters
©2007
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Componentsof a gas/liquid separator
©2007
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Horizontal 2 phase separator components/internals
Mist extractor
Settling section
Secondarychamber
Primary chamber
Diffuser
Gas + liquids inlet
Decantationchamber Separation
partition
Purge
Anti-wavepartition
Chassis
Oil outlet
Gas
outlet
©2007
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ingPRO01198 – CRUDE OIL TREATMENT - Separation
5- Foamingdifficult gas/liquid separation
©2007
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Foaming
Origin
• Gas expansion + oil / gas surface tension
• Pure liquids do not foamA surfactant is neededMixtures of isomers in hydrocarbons are surfactants
• Foams are unstable (state of least energy)
• The internal viscosity of the oil stabilises the foam, leading to drawing along of the gas (foaming)
Theory
©2007
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FOAMS
– FOAMS are oil + gas "emulsions"
T=15mn
©2007
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– INCONVENIENTS :
• oil entrainments in gas (affecting scrubbers, flares, compressors protection, gas treatment solvents ...), and gas entrainments in oil ( pump cavitation, later degassing...)
• loss of control of levels in separators
FOAMS – Inconvenience
©2007
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GAZ
• the speed of drainage is
dependant of the viscosity of
the oil
•the max width is dependant
of the liquid interfacial
tension
INTERFACIAL FILM
FOAMS – Schematic representation
©2007
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•• NATURAL SURFACTANTSNATURAL SURFACTANTS
•• ADDED SURFACTANTS (PRODUCTION CHEMICALS)ADDED SURFACTANTS (PRODUCTION CHEMICALS)
•• SOLID PARTICULESSOLID PARTICULES
•• WATER DROPLETSWATER DROPLETS
FOAMS STABILISATION
©2007
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Foaming is dependant on crude characteristics
BUT
• If asphaltene content > 1 %, higher foaming and stability
• if acid index >0.2 mg KOH/l, lower quantity of foam & higher stability
• The % of water and additives (anticorrosion etc… ) do not appear to
have any effect on the phenomenon
Tendency to foam
API 40 = .825 API 30 = .876
Increase in % vol.Foam breaking in seconds
API > 40 30 < API < 40 API < 30
10 - 20 20 - 40 > 50
30 30 - 60 > 60
©2007
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• THE VERTICAL SPEED OF GAS BUBBLES IS HIGH DUE TO THE
HIGH DENSITY DIFFERENCE WITH THE OIL (STOKES LAW)
• GAS BUBBLES FLOCCULATE AT THE SURFACE AND CREATE A
"MATTRESS"
• COALESCENCE BECOMES THE LIMITING FACTOR
– THE LIQUID IS DRAINED OUT OF THE INTERFACIAL FILM
DECREASING ITS WIDTH UNTIL A MINIMUM VALUE IS REACHED
WHERE IT BREAKS
– BREAKING WIDTHS ARE MUCH THINNER THAN FOR EMULSIONS
FOAMS : separation / breaking
©2007
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•• IT IS POSSIBLE TO :IT IS POSSIBLE TO :
–– increase the breaking width of the foam by adding a chemicalincrease the breaking width of the foam by adding a chemical
–– increase the speed of drainage by lowering the liquid increase the speed of drainage by lowering the liquid
viscosity (HEAT)viscosity (HEAT)
–– install separator internals acting on install separator internals acting on wettabilitywettability
–– use separators equipped with specific cyclonic inlet devicesuse separators equipped with specific cyclonic inlet devices
FOAMS TREATMENT
©2007
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Treatment
• Mechanical - Washing- longer time spent in installation
• Chemical - anti-foam
FOAMS TREATMENT
©2007
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Chemical Treatment
Action:• displace the foam stabilizing element from the bubble walls• or cause bubbles to burst locally
Necessary conditions:• be soluble in the foaming system• disperse satisfactorily• have surface tension < that of the foam
ANTI-FOAMS
FOAMS TREATMENTS : anti-foams
©2007
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antianti--foam additivesfoam additives
– MOSTLY USED : SILICONE OILS ( POLYSILOXANES )
– EFFICIENT AT 2/3 ppm (4 to 5 ppm if diluted )
– HAVE TO BE INJECTED UPSTREAM THE SEPARATOR BUT THE
CLOSER FROM THE INLET
• LOSS OF EFFICIENCY AFTER A CERTAIN PERIOD OF TIME)
• LOOSE THEIR EFFICIENCY WHEN TOO MUCH MIXED WITH THE CRUDE
THESE PRODUCTS ARE REFINERY CATALYSTS POISONS
their dosage have to be strictly controlled
FOAMS TREATMENTS : anti-foams
©2007
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OTHER PRODUCTSOTHER PRODUCTS ::
– Heavy Alcohols, cheap but weak efficiency
– fluoro-Silicones, very efficient but expensive
• to be used in severe cases
�Selection implemented in the Flash Foaming Test (Lab)
FOAMS TREATMENTS : anti-foams
©2007
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CRUDE OIL FOAMING TENDENCIES
FLASH FOAMING TESTFLASH FOAMING TEST
MPI
TR
TR
OILSTORAGE NITROGEN
BUTANE
TO WATER BATH
CALIBRATED CYLINDER
ADJUSTABLECONTROL VALVE
( 35 L/H)
PROCEDURE
P = 10 BARS with N2 / BUTANE
T = 60 ° C
600 CC OIL
©2007
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Gutter separatorfor foam treatment
Diffuser
Oil
Inclinedplates
Inlet
Mist extractor
Gas
FOAMS TREATMENTS : mechanical
©2007
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FOAMS TREATMENTS : mechanical
©2007
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Section X-X
FOAMS TREATMENTS : mechanical
DIXON PLATES
©2007
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Foam treatmentby heating
in salt water bath
Mist extractor
Inlet
Burner
LC(water)
Water
LC(water)
oil
Gas
Gas
PC (gas)
Oil
Heating
Salt water
FOAMS TREATMENTS : mechanical
©2007
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•• FOAMS ARE SIMILAR TO EMULSIONSFOAMS ARE SIMILAR TO EMULSIONS
•• HEAVY OILS (viscous) OR ACID/NAPHTENIC CRUDES HEAVY OILS (viscous) OR ACID/NAPHTENIC CRUDES
(natural surfactants) ARE CREATING STRONG FOAMS(natural surfactants) ARE CREATING STRONG FOAMS
•• IF FOAMING HAS BEEN ANTICIPATED, OVERSIZING IF FOAMING HAS BEEN ANTICIPATED, OVERSIZING
OF SEPARATORS OR SEPARATOR INTERNALS CAN OF SEPARATORS OR SEPARATOR INTERNALS CAN
BE CHOSEN TO LIMIT INCONVENIENTSBE CHOSEN TO LIMIT INCONVENIENTS
•• IF NOT, FOAM TREATMENT USUALLY REQUIRES IF NOT, FOAM TREATMENT USUALLY REQUIRES
HEAT + CHEMICAL TREATMENTHEAT + CHEMICAL TREATMENT
FOAMS - CONCLUSIONS
©2007
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CRUDE OIL PROCESSING - SEPARATION
©2007
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Pressure (bars)
300
250
200
150
100
50
00 50 100 150 200
100 %98.497.29694.4
91.7
88.9
85.1
80
T(° C)TG
P1
Bubble curve
88.9 %
Flash liberation
Yield (R)
©2007
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Pressure (bars)
300
250
200
150
100
50
00 50 100 150 200
100 %
95.0
88.1
86.2
T(° C)TG
P1
Initial bubble
curve in the
reservoir
83.792 %
Elimination of gas
Bubble curve atperforations
Differential liberation
Yield (R)
©2007
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Pressure (bars)
300
250
200
150
100
50
0
0 50 100 150 200
100 %
91.0
88.9
T(° C)TG
P1
Initial bubble
curve in the
reservoir
84.790 % 1st stage separation
gas elimination
Perforations
86.7
Well headBubble curveat perforations
Composite liberation
Yield (R)