Natural gas processing

1. Process & Treatment
T h e A r t o f
Eng. Elsayed Amer

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El Sayed Amer
▪ Bachelor's degree of Petroleum & Natural Gas Engineering 2012.
▪ Current Senior Process and Production Engineer at Suez Oil Co “SUCO” since 2014.
▪ Worked for Weatherford drilling international for 2 years as well drilling and completion engineer.
▪ Instructor for Oil & Gas Upstream and downstream courses at MTC Egypt, Egyptian syndicates of
engineers, OGS, SPE, AAPG & OPA.
▪ Member of SPE, AAPG, AACE, NACE, Environmental Geoscience.
▪ IWCF , HYSYS process modeling, Eclipse certified.
https://bit.ly/2UFSgpn
01065860658
Eng20072007@gmail.com
/elsayedameer

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References
Gas Process Course

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Reservoir Fluids
BARREL OF CRUDE OIL
▪ WELL FLUIDS
▪ Well fluids are often a complex mixture of liquid hydrocarbons, gas, and some impurities.
▪ It is necessary to remove the gas and impurities from the liquid hydrocarbons before they are
stored, transported and sold.

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The products from a barrel of oil
emulsion layered

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Fluid emulsion

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Fluid condition in pipeline

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SEPARATOR
Definition
▪ A pressure vessel, Used for separating well fluids of oil and gas wells into gaseous and
liquid components.

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Separator Functions
Functions
▪ Downstream equipment cannot handle gas–liquid mixture:
▪ Pumps require gas-free liquid to avoid cavitation.
▪ Compressor and dehydration equipment require liquid-free gas.
▪ Product specification set limits on impurities.
▪ Oil generally cannot contain more than 1% BS&W.
▪ Gas sales contracts require gas free of liquids.
▪ Measurement devices for gases or liquids are highly inaccurate when
another phase is present.

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Factors Affecting Separation
▪ The Seven Principles of Oil Separation
1. Pressure change
2. Temperature change
3. Gravity
4. Scrubbing action
5. Chemical action
6. Electrical
7. Retention time
Separation
Water
Condensate
Oil
Gas

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Process flow diagram PFD

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Factors Affecting Separation
▪ Heat
▪ When separating liquids from each
other, heating to certain
temperatures enhances separation.
▪ When the temperature of an oil and
water emulsion is increased,
the viscosity of oil is decreased. This
lower viscosity allows the gas and
water molecules to be more easily
released. Heating oil emulsions also
increases density between oil and
water.
▪ A heater treater is an example

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Factors Affecting Separation
▪ Heat

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Factors Affecting Separation
▪ Gravity
▪ most widely used method for oil
emulsion separation.
▪ The elements in the well stream such as
oil and water have different gravities.
▪ The density differences allow water to
separate by gravity.

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Factors Affecting Separation
▪ RETENTION TIME
▪ Separation occurs over time.
▪ When you reduce the velocity of a fluid, you allow the fluid a certain amount of
time for it to be separated by gravity.
▪ Retention time is the amount of time the fluid stays in a steady or non-agitated
state inside a separator. Longer retention time means more separation.
▪ A larger-diameter or taller vessel will increase the retention time and allow
more water to settle out by gravity.

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Separators Classification

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Separators
Configuration
( Shape )
Vertical
Horizontal
Spherical
Function
Separator
Scrubber
K.O.D
Flash Drum
No of phase
separation
Two phase
Three phase
Operating
pressure
Low
( 20 – 200 Psi)
Medium
(200-750 Psi)
High
( 750 - 1500 Psi
Application
LTS
Test
Separator
Production
separator

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1. Based on Geometry
Spherical

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Vertical Separator
Separator classification
• A vessel with its cylindrical axes
perpendicular to the ground that
is used to separate oil, gas and
water from the production
stream.
• The vessel can be a two-phase or
three-phase separator.

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Vertical Separator
Separator classification

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Vertical Separator
Separator classification

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Vertical Separator
Separator classification

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Advantages & Disadvantages
Advantages Disadvantages
Ideal for high flow rate. Difficult for modular systems - transport & installation.
Good for surging flows Good for surging flows
Work well for high GOR applications Low efficient in high liquid rate
Can handle foaming liquids
instruments and safety devices may be difficult to access
without ladders
Economical capital cost
less space than a horizontal separator with the same capacity
Can handle more sand, mud, paraffin, wax without plugging.
can be skid-mounted for quick and easy installation

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Horizontal Separator
Separator classification
• A horizontal separator is a vessel for
the bulk removal of liquids or solids
by gravity.
• These separators may go by many
names :
1. horizontal separators,
2. oil-water separator,
3. three-phase separators,
4. two-phase separators,
• functionality is all relatively the same.

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Horizontal Separator
Separator classification

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Horizontal Separator
Separator classification

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designblast
template
01. with Boot or Water Pot
02. Double barrel
Horizontal Separator.
Special Types of
03. Filter Separators
Horizontal Separator
Separator classification

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Horizontal Separator
Separator classification
A. with a Boot or Water Pot
• It is used when there are very
low liquid flow rates,
especially where the flow
rates are low enough that the
“boot” can serves a liquid-
liquid separator as well.

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Horizontal Separator
Separator classification
A. oil bucket and water weir

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Horizontal Separator
Separator classification
B. Double barrel Separator
• Double-barrel horizontal
separators are commonly used in
applications where there are high
gas flow rates and where there is
a possibility of large liquid slugs.
1. High-efficiency liquid slug removal
2. No liquid re-entrainment
3. Extremely high gas throughput
4. Lower barrel acts as a quiet
5. retention chamber

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Horizontal Separator
Separator classification
B. Double barrel Separator

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Horizontal Separator
Separator classification
B. Double barrel Separator
Uses:
• Rarely used because more expensive than single-tube (or single-barrel)
❑ horizontal separators possess the following advantages over double barrel types
1. lower initial cost —easier to insulate in cold weather operations
2. liquid remains warmer, minimizing freezing and paraffin deposition
Advantages:
• larger capacity under surging
• better separations of solution gas in the quiescent lower chamber
• better separation of gases and liquid of similar densities
• more stable liquid-level control

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Advantages & Disadvantages
Advantages Disadvantages
Normally more efficient to handle large amounts of liquid and gas Only part of shell available for passage of gas.
Cheaper than Vertical separator for same capacity. Occupies more space unless “stack” mounted.
Large liquid surface area for foam dispersion generally reduces
turbulence
Liquid level control is more critical.
Require smaller diameter for similar gas capacity as compared to
vertical vessels.
More difficult to clean produced sand, mud, wax, paraffin, and Poor
solids removal.
No counterflow
Larger surge volume capacity

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Spherical Separator
Separator classification
• A ball-shaped vessel used for fluid
separation.
• A spherical separator can be used for two-
phase or three-phase separation purposes.
Spherical separators are less efficient than
either horizontal or vertical cylindrical
separators and are seldom used.

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Spherical Separator
Separator classification
• Can accommodate large surges of
liquids.
• Well suited for high sediment loads;
conical bottoms are sometimes
attached for large volumes of
sediment.
• These separators occupy less floor
space than horizontal types and are
often found on offshore platforms
where floor space is at a premium.

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• Can accommodate large surges of liquids.
They are well suited for high sediment loads;
conical bottoms are sometimes attached for
large volumes of sediment.
• Vertical separators are preferred when well
streams have large liquid-to-gas ratios.
• These separators occupy less floor space than
horizontal types and are often found on
offshore platforms where floor space is at a
premium.
1.BasedonGeometry

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Spherical Separator
Separator classification
III.
Spherical
Separator

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Separators Ideal Usage
Separator classification
Vertical Horizontal Spherical
Low to intermediate gas-oil
ratio, and where relatively
large slugs of liquid are
expected
High gas-oil ratio crudes,
foaming crudes, or for
liquid- liquid separation.
Good for a diverse range of
situations
Intermediate or low gas-
oil ratio, preferably two-
phase separation

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Vertical Horizontal Spherical
Advantages 1. Easier to clean and can handle large
quantities of sand
2. Saves space (occupies lesser ground
area)
3. Provides better surge control
4. Liquid level control is not critical
5. Less tendency for revalorization of
liquid into the gas phase due to the
relatively greater vertical distance
between liquid level and the gas
outlet
1. Can handle much higher GOR well-
streams because the design permits
much higher gas velocities
2. Cheaper than the vertical separator
3. Easier and cheaper to ship and
assemble
4. Requires less piping for field
connections
5. Reduces turbulence and reduces
foaming (thus, it can handle
foaming crudes)
6. Several separators may be stacked,
minimizing space requirements
1. Very inexpensive
2. Good for low or intermediate
GOR’s
3. Very compact and easy to
ship and install
4. Better clean-out
Disadvantages
1. It takes a longer-diameter separator
for a given gas capacity as compared
to a horizontal separator
2. More expensive to fabricate
3. Difficult and more expensive to ship
(transport)
1. Greater space requirements
generally
2. Liquid level control more critical
3. Surge space is somewhat limited
4. Much harder to clean (hence a bad
choice in any sand-producing area)
1. Very limited liquid settling
section and rather difficult to
use for three-phase
separation
2. Liquid level control is very
critical
3. Very limited surge space

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Separators Classification
2. Based on Function
Two Phase separators
Three Phase separators

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Two Phase Separator
Separator classification
Used to separate only two phases
• Oil and gas separator
• Water gas separator
• Oil water separator
Divided into :
• Vertical two phase separator
• Horizontal two phase separator

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Vertical Two Phase Separator
Separator classification

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Horizontal Two Phase Separator
Separator classification

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Three Phase Separator
Separator classification
• Used to separate three phases
▪ OIL , Gas and water
• Divided into :
• Vertical three phase separator
• Horizontal three phase separator

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Vertical Three Phase Separator
Separator classification

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Horizontal Three Phase Separator
Separator classification

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Separators Classification
3. Based on Operating pressure
01
02
03
▪ From 10 to 225 psi.
▪ From 230 to 700 psi.
▪ From 750 to 1,500 psi.
Low Pressure
Medium
Pressure
High Pressure

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Stage Separator
Separator classification

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Stage Separator
Separator classification

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Test Separator
Production Separator
Low temperature separator
Elevated separator
01
03
04
02
Stage separator
Metering separator
Foam Separator
Free water Knock out drum
05
07
08
06
Separators Classification
3. Based on application

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TEST Separator
Separator classification
• Is used to separate and to meter the
well fluids.
• Can be permanently installed or
portable (skid or trailer mounted).
• Standards Test separators are available
in 1,440 psi, 720 psi and 600 psi
versions, but the 1440 psi version is by
far the most common.

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TEST Separator
Separator classification

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TEST Separator
Separator classification

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TEST Separator
Separator classification

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Slug catcher
Separator classification
There are basically two types of slug catchers:
• Vessel type
• multiple-pipe types (Finger type)
1. Vessel type slug catcher is simply gas-liquid separator that
combine slug catching with liquid storage.
2. The multi-pipe slug catcher is made up of a liquid and gas
separation entry slot and a series of parallel tilted bottles
where the liquid is stored.

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Slug catcher
Separator classification
VesselType Slugcatcher

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Slug catcher
Separator classification
Fingertype Slugcatcher
If a pipe-finger slug-catcher has been selected the number of standard
large diameter 36”, 42” and 48” tubes

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Classificationofseparators
Fingertype Slugcatcher

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Classificationofseparators
Fingertype Slugcatcher

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Slug Catcher Characteristics
Finger Type Vessel Type
Economical way to catch large slugs
Can give small particle separation (10 microns)
where there is liquid and lower gas flow
Gives predictable particle separation in the 50
micron and up sizes
It is possible to be used as a three-phase
separator
Predictable separation up to tens of thousands of
barrels slug size
Becomes expensive and heavy when large sizes
are required
Shipping in pieces for field assembly with line
pipe
When the slug size is up to 5-700 bbl., the
separation performance is good
When slug size is large enough to justify the
logistics of field assembly, and B31.8 type
construction allowed, the harp type
separator/slug catcher will be considerably
cheaper than vessels

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Scrubber
Separator classification
A scrubber is a two-phase separator that is designed to recover
liquids carried over from the gas outlets of production separators
or to catch liquids condensed due to cooling or pressure drops.
Applications:
1. upstream of mechanical equipment such as compressors that
could be damaged, destroyed, or rendered ineffective by free
liquid;
2. downstream of equipment that can cause liquids to condense
from a gas stream (such as coolers);
3. upstream of gas dehydration equipment that would lose
efficiency, be damaged, or destroyed if contaminated with
liquid hydrocarbons;

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Scrubber
Separator classification

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Scrubber
Separator classification

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Free water knockout
Separator classification
▪ A free water knockout (commonly
abbreviated FWKO) is an oil and gas
production vessel designed to separate
free water from oil and gas.
▪ The water is removed for disposal.
▪ Pressure is usual under 250 PSI

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Free water knockout
Separator classification

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Flare knockout drum
Separator classification
▪ FKOD
▪ A flare knockout drum is a vessel in the flare
header that is designed to remove and
accumulate the liquids that are condensed
from the relief gases. It is the primary
component in a pressure-relief

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Separator Internals

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Separator Internals

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1. Inlet Diverters
Separator Internals
▪ Also Known as Inlet Deflectors & Deflector Plate
▪ Locate in front of the flow inlet
▪ Cause a rapid change in direction & velocity of fluid.
▪ Forcing the liquids to fall to the bottom of the vessel.
▪ Responsible for the initial gross separation of liquid and gas.

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1. Inlet Diverters
Separator Internals

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1. Inlet Diverters
Separator Internals

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1. Inlet Diverters
Separator Internals

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2. Mist extractor
Separator Internals
▪ Also Known as Demister
▪ Used to remove vapour liquids from the gas
▪ Three general types:
I. Mesh
II. Vane
III. Fiber bed

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2. Mist extractor
Separator Internals

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2. Mist extractor
Separator Internals

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3. Vortex Breaker
Separator Internals
The formation of vortices can entrain vapor in the liquid
stream, leading to poor separation in process steps such
as distillation or excessive pressure drop, or causing
cavitation of downstream pumps. Vortices can also re-
entrain solid particles previously separated from a gas
stream in a solid-gas separation device such as a cyclone

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4. Weir
Separator Internals
▪ The oil and emulsion separate, forming a layer (or “pad”) above the free water.
▪ A weir maintains oil level, while an interface liquid level controller maintains the water level.
▪ The oil spills over the top of the weir, and then a level controller, which operates the oil dump
valve, controls its level.