2. • Produced well head mixtures are complex in
nature .
• They are mixtures of different Compounds of
hydrogen and carbon, all with different densities,
vapor pressures, and other physical
characteristics.
• In oil and gas separator design , they are
mechanically separated from a hydrocarbon
stream, the liquid and gas components that exist
at a specific temperature and pressure.
3. Functional sections of a gas- liquid
separator
• A typical gas - liquid separator consists of four
major sections
• 1. inlet diverter section
• 2. liquid collection section
• 3. Gravity settling section
• 4. mist extractor section
6. Inlet diverter section
• It is referred as primary separation section.
• Typically a stream enters with high velocity.
• Due to high velocity , the fluids enter the
separator with a high momentum.
• This diverter changes the flow and absorbs
the momentum of the liquid, and separation
of liquid and gas occurs .
7. Types of inlet diverters.
• Two main types of inlet separators
• 1. baffle plates
• 2. centrifugal diverters
• A baffle plate can be a spherical dish, flat
plate, angle iron, cone, which will accomplish
a rapid change in direction and velocity of the
fluids and thus disengage the gas and liquid.
8.
9. • Centrifugal inlet diverters use centrifugal force,
rather than mechanical agitation, to disengage
the oil and gas.
• These devices can have a cyclonic chimney or
may use a tangential fluid race around the walls.
• Centrifugal inlet diverters are proprietary but
generally use an inlet nozzle sufficient to create a
fluid velocity of about 20 fps.
• Centrifugal diverters work well in initial gas
separation and help to prevent foaming in crudes.
10.
11. Liquid collection section
• It is located at the bottom of the vessel.
• It provides the retention time for a gas in the
liquid to escape to the gravity settling section .
• It provide a surge volume to handle slugs.
• Degree of separation depends upon retention
time.
12. Retention time
• The retention time in a separator is determined
by dividing the liquid volume inside the vessel by
the liquid flow rate.
• It is effected by differential density of the fluids.
• Liquid –liquid separation requires larger
retention time compared to gas –liquid.
• The retention time usually varies between 30
seconds and 3 minutes.
• If a foaming crude is present, the retention
time could be increased by four times its normal
values.
13. Gravity settling section
• The gas stream enters the gravity settling
section , there the velocity drops and small
liquids droplets entrained by the gas that are
not separated by the inlet diverter are
separated here and fall to gas liquid interface.
• Liquid size greater than 100 to 140 microns fall
to the gas liquid interface and smaller droplets
remain with the gas.
14. Mist extractor section
• Gas leaving the gravity settling section
contains small liquid droplets, less than 100 to
140 microns.
• Gas leaving the vessel is passed through a
coalescing section or mist extractor.
• In this section , small amount of liquids
droplets are removed
