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Liquid and gas separation

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Oil and gas processing (Onshore)

Oil & gas separationSEPARATOR:

Pressure vessel separating well fluids into gaseous/ vapour and liquid components

Main facilities and operations in oil installation1)Well head & choke 1)Well 2)Flow lines 2)Flow 3)Manifold facilities 3)Manifold 4)Testing of wells 4)Testing 5)Liquid and gas separation facilities 5)Liquid 6)Oil and gas dehydration system 6)Oil 7)Desalting 7)Desalting 8)Storage 8)Storage 9)Shipment of products 9)Shipment

Main facilities and operations in GGS-Oil and gas metering -Instrumentation and control system Instrumentation -Maintenance of equipments Maintenance -Information & communication system Information -Utilities e.g. power, water and air Utilities -Office building Office -Fire fighting facilities Fire -Transportation Transportation -

Oil & gas separationSEPARATORS OF PRODUCING FIELD: Oil & gas separator Stage separator Trap Knock out vessel/drum/trap or

liquid knock out Flash chamber /vessel/ trap Expansion separator /vessel Gas scrubber (dry/wet ) Gas filter ( dry/wet) Filter /Separator

Well head and well fluids Multiphase HC mixture with varying compositions and densities Gas phase Liquid phase: 2 immiscible liquids Oil Water

FTHP FTHT

ABP ABT Choke

3.5/4 4/5 km. API 5L

SBHP FBHP SBHT

Well manifoldTo HP separator WELL#1 WELL#2 PG NRV

PG

NRV To MP separator

WELL#3

PG

NRV HP MP Test Headers

To test separator

Block diagram well fluids processingWell Fluid from header Gas to GDU/ Consumers

Separator Crude oil to dehydrator Produced water to ETP

Utilization of gas and oil

Gas is used for value added products -LPG -C2/C3 -Gas to consumers

Oil is supplied to refineries for distillation

Classification of Installationsa)For one or two wells: well head installation (WHI) a)For b)For many oil wells: group gathering station (GGS) b)For c)For gas wells: gas collecting station (GCS) c)For d)For oil storage and shipment : central tank farm (CTF) d)For e)For gas shipment : gas compressor plant (GCP) e)For f)For gas conditioning: Gas dehydration unit (GDU) f)For & gas sweetening unit (GSU) g) For water handling: Effluent treatment plant (ETP) h)Other plants: LPG recovery, C2-C3 unit, CSU etc. h)Other

Well connection configuration Multiphase HC mixture and water flowing through individual lines (preferred)WELL WELL

WELL WELL

WELL

GGS

WELL WELL WELL WELL

Well connection configuration Multiphase HC mixture and water flowing through interconnected lines (not preferred)WELL WELL WELL WELL WELL

GGSWELL

WELL WELL WELL

Well connection configurationMultiphase mixture flowing through well pads and group & test lines to GGS

WELL

WELL

WELL WELLPad

WELL

Pad

WELL

WELL

GGSWELL WELL

Well connection configuration Central Tank Form (CTF)Well Well Well Well Well Well Well Well

GGS

Well Well Well

Well Well Well

GGSWell

Well Well

WellGGS

CTFPump

Typical PFD of GGSFlare headerBath heater

BH HP MP

KOD

Flare

To consumers BH BH HP MP Test Scrubber To flare Oil Stb. To ETPHeater treater

Test HT Tank

Pump

Typical PFD of GCSFlare headerMeOH or BH KOD

Flare

HP

MP Scrubber

Consumers

To flare Test HP MP Test Cond. Stb. To ETP Cond. Stb. Tank Pump

Oil & gas separationWELL FLUIDS: Mixture of oil, gas and water / Free gas

Impurities / Extraneous material Nitrogen, CO2, H2S etc., Water, Paraffin Sand, silt etc.,

Oil & gas separationQuality of separated fluids

Separated crude oil

Depending on retention time, Free gas content in separated oil = 1.5% to 20% Water content of separated Oil = 0.05% to 8%

Quality improvement possible by chemical,

equipment, techniques and procedures

Oil & gas separationQuality of separated fluids

Separated water: Depending on retention time, Oil content in eff. Water = 0.004% to 2.0%

Special methods and separating techniques can improve water quality. Difference in sp.gr. of oil and water less than 0.2 results in limited and incomplete separation.

Oil & gas separationQuality of separated fluids

Separated Gas: For a separator with suitable mist extractor, Oil content in separated gas = 0.101 to 1.0 gal/mmscf In case of gas scrubbers oil content in effluent gas should be less than 0.1 gal/mmscf.

Oil & gas separation

Measurement

Instruments for measuring quality of separated fluids:

Instrument

Oil in separated gas Gas in separated oil Water in separated oil Oil in effluent water

Laser liq. Particle spectrometer Nucleonic densitometer BS&W monitor Ultraviolet absorption unit/ Solvent extraction/

Oil & gas separationFunctions of separatorsPrimary functions1.

Secondary functions1. Maintain optimum pressure 2. Maintain liquid seal

Removal of oil from gas

2. Removal of gas from oil 3. Removal of oil from water

Oil & gas separationProcess of separation:Separation of bulk liquid from gas Scrubbing of the gas Retaining liquids long enough for free gas separation Controlling and maintaining gas oil interface. Removal of all products from their respective out lets.

Reduction in gas velocity to allow liquids to drop out

Oil & gas separationClassification of separatorsPrinciple of primary sep. Operating pressure

Configuration Application

Function 2-phase 3-phase

Vertical Horizontal Spherical

Test sep. Prodn. Sep. L.T.S. Elevated sep. Stage sep. Metering sep. Foam sep.

Low pr. Sep. (10 - 225psi) Med. Pr. Sep. (225 - 750 psi) High pr. Sep. (750 - 1500 psi Gravity sep. Impingement/ coalescence sep. centrifugal sep.

Oil & gas separation

Stage separation of oil and gas:Series of separators operating at sequentially reduced pressures. Liquid is discharged from high pressure separator into the next lower pressure separator Aims at maximum recovery of liquid hydrocarbon and maximum stabilization of separated fluids. Economics limits the no. of stages of separation to 3 to 4

Oil & gas separation

Stabilization of crude oil :Operation of separator under vacuum / at high temp.

Liquid discharged completely stabilized Liquid recovery comparable to that of 4-6 stage separation Results in increased profit for highly volatile liquids Initial cost of stabilizer less than initial cost of multiple stage oil and gas separators.

SeparatorsBenefits of separation Separated gas, crude oil and produced water can be processed easily at low cost Removal of water helps in reducing damage due to corrosion Less costly MOC can be used if water is removed Less energy is required to move single phases

SEPARATION Depends on following factors: Pressure Temperature Gas Oil Ratio (GOR) Flow rate Fluid properties like density, viscosity etc.

Oil & gas separationPrinciples of separation of Oil from gas Density difference Impingement Change of flow direction Change of flow velocity Centrifugal force Coalescence Filtering

Oil & gas separation

Principles of separation of Gas from oil Settling Agitation Baffling Heat Chemicals

PRINCIPLES OF SEPARATION: Based on one or more of the following: Removal of Oil from Gas Gravity Separation Impingement Change of flow direction Change of flow velocity Filtering Coalescence Centrifugal Removal of Gas from Oil Settling Agitation Baffling Heat Chemicals

PRINCIPLES OF SEPARATION (OIL FROM GAS) : Gravity Separation Diff. Liquid phases Diff. Densities Diff. momentum

PRINCIPLES OF SEPARATION (OIL FROM GAS) : Gravity Separation: Terminal / Free settling velocity of droplet

Max. allowable gas velocityVt = [4 g Dp ( l - g) / 3 g C]

PRINCIPLES OF SEPARATION (OIL FROM GAS) : Impingement : If a flowing stream of of gas containing liquid mist is impinged against a surface, the liquid mist may adhere to and coalesce on the surface.

PRINCIPLES OF SEPARATION OIL FROM GAS : (OIL FROM GAS) Change of flow direction: Change in flow direction: Change in inertia Gas assumes change in direction readily Liquid gets retarded and flow back

PRINCIPLES OF SEPARATION OIL FROM GAS : : (OIL FROM GAS) Change of flow velocity: Change in flow velocity: Change in inertia Increase / decrease in velocity: High inertia liquid moves away from gas

PRINCIPLES OF SEPARATION OIL FROM GAS : : (OIL FROM GAS) Filtering : Porous filters are effective to remove liquid mist. Uses the principles of impingement, change in direction, change in velocity and coalescence.

PRINCIPLES OF SEPARATION OIL FROM GAS : : PRINCIPLES OF SEPARATION : FROM GAS) (OIL Coalescing Coalescing of small droplets (mist/fog)

Formation of large droplets

Settling by gravity

PRINCIPLES OF SEPARATION OIL FROM GAS : (OIL FROM GAS): Centrifugal force: Fluids allowed to flow in circular motion at high velocity. Centrifugal force throws liquid mist outward against the walls of the vessel.

PRINCIPLES OF SEPARATION (GAS FROM OIL ): Settling : Non solution gas separate on adequate retention time Optimum removal of gas if body of oil is thin

PRINCIPLES OF SEPARATION (GAS FROM OIL ): Agitation/Baffling: Controlled agitation helps removing non solution gas Disperses oil in such a manner that gas readily escapes Allows gas bubbles coalesce and separate

PRINCIPLES OF SEPARATION (GAS FROM OIL ): Heat : Hydraulically retained gas releases reduction of surface tension or viscosity on

Heat reduces surface tension and viscosity of oil.

PRINCIPLES OF SEPARATION GAS FROM OIL :): (GAS FROM OIL Chemical : Hydraulically retained gas releases on reduction of surface tension or viscosity Certain chemicals can reduce surface tension and foaming tendency of oil.

PRINCIPLES OF SEPARATION GAS FROM OIL :): (GAS FROM OIL Centrifugal force : Heavier oil is thrown outward against wall of vortex retainer and gas occupies inner portion. Properly designed vortex allow gas to ascend and liquid to flow downward

CLASSIFICATION OF SEPARATORS: SEPARATORS1.Two phase separator Separation of liquid (oil + water) and gas 2.Three phase separator Separation of liquid and gas Separation of water and oil

MAIN SECTIONS/COMPONENTS OF A SEPARATORHORIZONTAL SEPARATOR

1.Primary separating section 2.Secondary or gravity separating section 3.Coalescing section 4.Sump or liquid section

Two Phase Inlet C

Gas Outlet Mesh Pad

A

B D

Liquid Outlet

Gas Outlet VERTICAL SEPARATOR Mesh Pad Two phase Inlet B

A

A Primary Separation B Gravity Settling C Coalescing D Liquid Collecting

D

Liquid Outlet

Oil & gas separation

Components of oil and gas separators:Primary separation device and /or section Secondary gravity settling section Mist extractor Gas out let Liquid settling section

Oil & gas separation

Components of oil and gas separators:Oil out let Water out let Vortex breakers Back pressure control valve Level control valves Pressure relief valves

Oil & gas separation

Essential features of separators:

Inlet baffle / Impingement baffle / divertor Adequate liquid capacity to handle liquid surges Adequate vessel diameter and height for vapor disengagement Internal baffle / defoaming plates Demister pad / mist eliminator

MAIN SECTIONS/COMPONENTS OF A SEPARATOR 1.Primary separating sectionInlet Diverter Vane type Mist Extractor

Vapor Outlet D v Two phase Inlet Downc omer

Separate bulk portion of free liquid from inlet stream Inlet diverter // Inlet diverter Inlet baffle // Inlet baffle Impingement Impingement baffle baffle

Liq. Outlet

MAIN SECTIONS/COMPONENTS OF A SEPARATOR 2.Secondary or gravity separating section Settling section Reduced turbulence Retention time Straightening vanes/ Straightening vanes/ Settling vanes Settling vanes Defoaming plates Defoaming plates

MAIN SECTIONS/COMPONENTS OF A SEPARATOR 3.Coalescing section Coalescer or mist extractor/demister pad Interwoven mesh Gets plugged very easily with heavier hydrocarbons or deposits Requires frequent cleaning Knitted wire mesh type Knitted wire mesh type

MAIN SECTIONS/COMPONENTS OF A SEPARATOR 3.Coalescing section Coalescer or mist extractor/ demister pad Does not require frequent cleaning Better suited to crudes having high wax and deposition tendency Vane type Vane type

MAIN SECTIONS/COMPONENTS OF A SEPARATOR 4.Sump / Liquid Collection Section Receiver for all liquid separated from well fluid in first 3 sections Minimum level required for liquid controls Requirement of surge volume for degassing or slug removal Vortex breaker Vortex breaker

SEPARATOR CONFIGURATION: 1.Vertical separator 2.Horizontal separator 3.Spherical separator 4.Centrifugal separator 5.Compact Separators/Hydro-cyclones Vertical and Horizontal type separators are the most common in the oil industry

SEPARATOR CONFIGURATION: 1.Vertical Separator (Advantages) Low to medium GOR streams When relatively large liquid slugs are expected Incidence of sand, paraffin, wax Limited plot space Ease of level control is desired Full diameter for gas & liq. flow

Vertical separators

Disadvantages - Larger diameter for given gas capacityMore difficult to skid mount and ship More difficult to reach and service top

mounted devices

SEPARATOR CONFIGURATION: 2.Horizontal Separator (Advantages) High to medium GOR streams Less difficult to skid mount and ship Larger volume of gas Foaming crude 3- separation

Horizontal separators

DisadvantagesOnly part of shell available for gas separation Occupies more area Liquid level control is more critical More difficult to clean produced sand

SEPARATOR SELECTION CRITERIA:Vertical Separator Low to medium GOR When large liquid slugs are expected Incidence of sand, paraffin or wax Horizontal Separator Medium to high GOR For larger volumes of gas For foaming crude

Limited plot space For 3- separation Ease of level control is desired

General guidelines for use VerticalCompressor KOD Fuel gas KOD Degassing boots Absorber feed KOD

HorizontalProduction separator 3-Phase separation Reflux drum Flare KOD

SEPARATOR CONFIGURATION: 3.Spherical Separator Most commonly used for separation of large vol. of gas from extremely small vol. of liquid High pressure service where compactness is desired Limited liquid surge capacity

SEPARATOR CONFIGURATION: 4. Centrifugal/compact separators

- Relatively new type ofseparators - Technology still developing

- Less efficient than other separators

Centrifugal/compact separators Advantages Less maintenance is involved Less space is required Light in weight Less expensive

Centrifugal/compact separators Disadvantages Not suitable for large liquid slugs Efficiency not as good as other types Narrow operating flow range for highest efficiency

Comparison of separators

Separator design guidelines Sufficient

residence time for both oil and water is provided to enable separation of water from oil and oil from water. free space is left at the top for separation of liquid from gas.

Enough

SEPARATOR SPECIFICATIONS: Retention time for liquid-liquid separation Retention time determines the liquid capacity of a separator API 12J recommendations are available for specifying retention time for 2- phase and 3- separator

SEPARATOR SPECIFICATIONS: Retention time for liquid-liquid separation API 12J allows equal retention times for both oil and water If problems such as foaming, wax, or slug flows are encountered, additional retention time may have to be considered

SEPARATOR SPECIFICATIONS :Retention time for liquid-liquid separationAPI RECOMM. FOR 2- SEPARATION Oil API Gravity Above 35 20 30 Retention time (min.) 1 1 to 2 2 to 4 API RECOMM. FOR 3- SEPARATION Oil API Gravity Above 35 Below 35, Sep temp > 100 oF Retention time (min.) 3 to 5 5 to 10

10 - 20

Below 35, Sep temp > 80 10 to 20 oF Below 35, Sep temp > 60 20 to 30 oF

SIZING CRITERIA FOR A SEPARATOR Holdup time: Time it takes to reduce the liquid level from NLL to LLL, while maintaining a normal outlet flow without feed make-up Based on the reserve required to maintain good control and safe operation of downstream facilitiesh1 h2 h3 h4 h5 h6 h7 h8 HLA HLL NLL LLL LLA

T

Di

T

T

SIZING CRITERIA FOR A SEPARATOR Surge time : Time it takes for the liquid level to rise from NLL to maximum or HLL, while maintaining a normal feed flow without any outlet flow Based on requirements to accumulate liquid as a result of upstream or downstream variations, e.g. slugs Normally, surge time is taken as of holdup time

Th1 h2 h3 h4 h5 HLA HLL NLL LLL h7 h8 LLA Di

h6

Design conditions for pressure vessels PressureOperating Pr (Bar) 0-10 10-35 35-70 > 70

Design Pr (Bar) MOP + 1 Bar MOP + 10% MOP + 3.5% MOP + 5%

MOP : Maximum operating pressure

Design conditions for pressure vessels Temperature

Max design temperature = Max op. temp + 15 oC Min Design temperature = Min op. temp 5 oC

Note : Minimum design temperature must take into account of depressurization of the vessel

Sizing of vertical separators

Calculate settling velocity

vs = k [ (l - v )/ v ]1/2 l = Liquid density, kg/m3 v = Vapour density, kg/m3 vs = settling velocity, m/s k = correlating factor(Find out from table)

Sizing of vertical separators

Derate calculated settling velocity by 85% for design margin. Calculate internal diameter Di= [ 4Q/ vs]1/2

Where Di = Internal dia, mm Q = Flow rate, M3/s Round the ID to nearest 50 mm.

Sizing of vertical separator

T

Height calculation

h1 h2 h3 h4 h5 HLA HLL NLL LLL h7 h8 LLA Di

T

h1= Max 15% of dia. or 400mm h2= 150mm for mesh pad h3= max ( 50% of dia. or 600mm) h4= 400mm +d/2; d: inlet nozzle,mm h5= calculate based on 1-2 min residence time at maximum liquid h6= calculate based on 4-5 min hold up time h7= calculate based on 1-2 min residence time h8= 300mm for bottom connection, 150mm for side connection H = h1+ h2 + h3 + h4 + h5 + h6 + h7 + h8 t

h6

Sizing of vertical separators

Wall thickness

t = {PDi / (2SE-1.2P)}+ C Di = Internal dia., mm t = wall thickness, mm P = design pressure, barg E = joint efficiency(use 1.0 for seamless shells 0.85 otherwise)

S = Max allowable stress, bar

Sizing of vertical separators

Weight calculation

- Shell weight with ellipsoid head Wt= s ( tDiHt+2x1.09xDi2)x10-9

Where W = Bare vessel weight with ellipsoid head, Kg t s = CS density = 7865.55 Kg/m3

Sizing of vertical separators

Weight calculation

- Shell weight with dished head Wt = s( tDiHt+2x0.842xDi2)x10-9

where: W = bare vessel weight with dished head, t Kg

s= CS density = 7865.55 Kg/m3

Sizing of vertical separators

Weight calculation

- Weight of the vessel can also be calculated from graph based on thickness, length and diameter.

Nozzle sizing of separatorsInlet nozzle Size based on normal volumetric flow + 10% Limit inlet velocity to 7-13 m/s Round nozzle diameter to nearest standard size

Gas outlet Size based on normal flow arte Limit velocity to 15-30 m/s

Liquid outlet Normal flow rate + 10% Limit velocity to 1-3 m/s for HC 2-4 M/S for water

SEPARATOR DESIGN :Horizontal 2- Separator Calculate settling velocity Vs Vessel diameter required for droplet separation D1= Qg/ .Vs.F.(L/D) Vessel dia. required for sufficient liquid residence Vessel time D2= 3 16Qltres /3 .(L/D) 16Q Select max. of D1 or D2.

Qg - Gas flow rate at Pr.& T m3/s Ql- Tot. liq. Flow rate - m3/s Vs- settling velocity - m/s D - Vessel Dia. -m L/D Vessel design ratio F - Security factor (0.85) tres liquid residence time -s

Three phase separation Types

of separatorsthree phase separator 3 phase separatorInter-phase control with weir Inter-phase control with boot

Vertical

Horizontal

Design guidelines for 3-ph separator Settling

time for separation of oil from water and water from oil is calculated based on: minimum flow

particle size

rates density difference fluid viscosities.

SEPARATOR DESIGN :Horizontal 3- Separator

When heavy liquid volume is not substantial ( 15-20% by wt.) When almost equal vol. of light and heavy liq. are present

DETERMINATION OF SEPARATION STAGES:Usually carried in more than one stages Usually Separation of HC mixture into vapor and liquid in two or more equilibrium phases at successively Separation lower pressures Storage tank is considered as one stage of separation Storage In actual field practice, 2 or 3 stage separation is considered to be optimal In

More stable stock tank liquid Enhanced liquid recovery

DETERMINATION OF SEPARATION STAGES:

DETERMINATION OF SEPARATION STAGES :TOTAL GOR : Ratio of total cumulative gas recovered from all stages per bbl of stock tank oil producedTotal GOR varies with no. of stages for a given crude Total Total GOR is lower for more no. of stages Total When total GOR is lower, more of light fractions remain in oil, thus increasing oil API gravity, thereby yielding higher incomeTotal GOR, scf/bsto

SEPARATOR SPECIFICATIONS: Separator efficiencyLiquid carryover in gas With mesh type ME, efficiency of 98-99% with droplet size smaller than 100

Gas content in oil Generally < 2 5 % by volume

Oil content in water < 300 500 mg/l due to environmental restrictions 35 1 Separators 20-30 1-2 10-20 2-4

3-Phase >35 3-5 separators Below35 100+o F 5-10 80+o F 10-20 60+o F 20-30

Oil & gas separationSizes and Capacities : Liquid levels

Maximum oil level Normal oil level

: < 0.65 I.D.

Low oil level

: 0.5 I.D. or 1 min. retention time between max. and normal liq. Level : 0.1 I.D. or 12 from bottom : Water retention time of 1-2

Water/ inter face level

Oil & gas separation Sizes and Capacities :

Design data required: Separator

operating temperature and

pressure Gas Oil Water

: Flow rate, Sp. Gr., acid gas content : Flow rate, Sp. Gr., viscosity, : Flow rate, Sp. Gr., viscosity,

corrosion and scaling tendencies.

Oil & gas separationSizes and Capacities : Design data required: Water : Flow rate, Sp. Gr., viscosity, corrosion and scaling tendencies. Impurities : Quantities and description of deposits and Vessel and coatings. Accessories: Codes to be followed, safety devices, and instrumentation desired. scales

: Type, Pr. Rating, corrosion allowance, connections

Oil & gas separation

Gas capacityBased on max. allowable gas velocity Max. allowable vap. Velocity (Vs) (Vs) = K ( L - V / V ) Where K= 4gDp / 3Cd

Oil & gas separationOil capacity Calculation based on retention time of the liquid in the vessel sufficient to obtain equilibrium between liquid and gas. Liquid settling volume (W) W = VL (t x 1440)

Where VL = Liquid capacity, bbl/d t = retention time, min.

Oil & gas separation

Design considerations:Sized for maximum flow rates Should take care of :

Heads/ slugs and pumping requirements Pumping , gas lift and naturally flowing wells .

Oil & gas separation Capacity of vertical and horizontal separators:

Nomographs/Curves available To To

size the separator determine the volume of fluid for a

given separator

Suitable for preliminary sizing

Oil & gas separation

Capacity of vertical and horizontal separators:Gas capacity : Does not vary directly with a change in shell length. The gas capacity of a horizontal separator is proportional to its length. The liquid capacities depend on the liquid retained in the settling section of the separators.

Oil & gas separation

Selection criteria of separators:Vertical separator applications Well Well

fluids having low GOR. fluids having sand, etc., limitation of space exits

Where Slug

flow from wells stream and upstream equipment.

Down

Oil & gas separation

Selection criteria of separators:Horizontal separator applications

Separation of water from oil Foaming crude oils Well fluids with high GOR Wells with relatively uniform flow Skid mounted or trailer mounted Stacking of multiple units.

Oil & gas separation

Selection criteria of separators:Spherical oil and gas separator applications

Well fluids having high GOR and constant flow rate Installations where both vertical and horizontal space/height limitations exist. As gas scrubbers down stream of process units.

Oil & gas separation

Controls of separators:Liquid level controllers for gas/ oil and oil/water interfaces. Gas back pressure control valves

Oil & gas separation

Valves of separators:Oil discharge control valve Water discharge control valve Drain valves Block valves Pressure relief valves Valves of sight glasses

Oil & gas separation

Accessories of separators:Pressure guages Thermometers Pressure reducing regulators Level sight glasses Safety head with rupture disk Piping and tubing

Oil & gas separation

Safety features in separators:High and low liquid level controls High and low pressure controls High and low temperature controls Safety relief valves Rupture disks

Oil & gas separation

Problems in oil and gas separation:Foaming of crude oil

Encasing of gas in thin film of oil Crudes that are likely to foam

crudes with oAPI < 40 Operating temp < 160 0 F Crude viscosity > 50 cP

Oil & gas separation

Problems in separation:Foaming of crude oil Effects

of foaming

Reduces the capacities of oil and gas separators Carry over of oil in gas Control of liquid levels

Oil & gas separation

Problems in separation:Foam management Addition Special

of foam depressants

designs for handling foaming

crude

Oil & gas separation

Problems in separation:Reduces efficiency of separators Can be removed by steam / solvents Can be prevented by coating

Paraffin

Oil & gas separation

Problems in separation:Reduces capacities of separators Sand removal by periodic draining Salt removal by mixing crude with water and draining the water.

Sand / silt / mud etc.,

Oil & gas separation

Problems in separation:Cause early failure of equipment Most corrosive components in gases are CO2 and H2S.

Corrosion

Operation and maintenance: Periodic inspection Installation of safety devices Safety heads / rupture disks Mist extractors Hydrate inhibition Corrosive inhibition paraffin controls

Oil & gas separation

Operation and maintenance in oil and gas

Oil & gas separation

separation: High capacity operations Pressure shock loads Throttling of discharge liquids Pressure guages Guage cocks and glasses Cleaning of vessels

Oil & gas separationPREVENTIVE MAINTENANCE OF SEPARATORS DailyCheck liquid levels Check pressure & temperatures Replace broken guage glasses & pressure guages

PeriodicallyLubricate valves Clean guage columns Check level control valves Check back pressure valves

YearlyCheck pressure relief valves

Oil & gas separationTROUBLE SHOOTINGLOW LIQUID LEVELFluid dump valve opening too wide or trim cut out Drain valve opening or leaking No fluid entering

Oil & gas separationTROUBLESHOOTINGHIGH LIQUID LEVELFluid control dump valve closed or plugged Block valve around dump valve closed Inlet valve to next vessel closed Separator overloaded

Oil & gas separationTROUBLE SHOOTINGLOW PRESSURE IN SEPARATORBack pressure control valve not working

Leaking safety relief valve Inlet valve closed

Oil & gas separationTROUBLE SHOOTINGHIGH PRESSURE IN SEPARATORBack pressure control valve not working

Separator downstream valve closed Plugged mist extractor

Oil & gas separationTROUBLE SHOOTINGALL THE OIL GOING OUT OF GAS LINE

Dump valve not open/partially open

Blocked valve closed in piping to tank Separator or piping plugged

Oil & gas separationTROUBLE SHOOTINGMIST GOING OUT OF GAS LINEVessel too small

Plugged mist extractor High liquid level Foaming problem

Oil & gas separationTROUBLE SHOOTINGFREE GAS GOING OUT OF OIL/WATER VALVE

Too low level in separator

Dump valve not seating Block valve around dump valve passing

Oil & gas separationTROUBLE SHOOTINGEXCESS GAS GOING TO TANK WITH OILLess retention time

Foaming oil Too much pressure drop from separator to tank

Oil & gas separationTROUBLE SHOOTINGOIL/CONDENSATE & WATER NOT SEPARATING IN 3 PHASE SEPARATOR

Paraffin problem hampering water from being free Not enough retention time Interface level control not working properly Leak in adjustable weir Adjustable weir height to be adjusted

Oil & gas separationTROUBLE SHOOTINGDIAPHRAGM OPER. DUMP VALVE NOT OPERATING

Pilot failure

Supply gas failure Out of adjustment Broken valve stem Plugged tubing Ruptured diaphragm Leak in line from pilot to valve

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