Midstream Oil and Gas, Pipeline Pump Station, Upstream Oil and Gas

Two Phase Separator vs. Three Phase Separator Differences

November 5, 2019 Welcome

two-phase separator vs. three-phase separator

Natural gas operators utilize several devices to purify well streams in offshore and onshore facilities before carrying out oil and gas measurement and sale.

Dehydrating natural gas helps to prevent several problems that occur in storage and transportation such as corrosion of storage vessels, inaccuracies in the metering of gas flow, and the presence of unwanted compounds within the product. Oil and gas separators are widely used for gas-liquid or oil-gas separation at processing facilities.

What Is a Separator Used for in Oil and Gas Operations?

A separator is a device used to separate a well stream mixture of oil/gas/water into its constituents. For example, a gas-liquid separator is used to extract and collect entrained fluids from natural gas streams. The two main categories of separators are two-phase and three-phase separators.

Two-Phase Separator vs. Three Phase Separator

Two-phase separators are used to separate well fluids into the liquid and gaseous fractions. A three-phase separator, on the other hand, separates well fluids into the water, oil, and gaseous components.

A Free water knockout (FWKO) is often classified as a three-phase separator because it can remove produced water from hydrocarbons held in storage vessels at oil and gas facilities.

Let’s take a closer look at these modular process skid units to better understand how they work.

Three Phase Separators for Oil and Gas

As stated earlier, three-phase separators extract the water, oil, and gas constituents from well fluids. Like two-phase systems, they can have a vertical or horizontal orientation.

A vertical three-phase separator is ideal for space-constrained applications due to its smaller footprint, but typically accommodates lower fluid volumes than horizontal separators. Horizontal separators take up more space but can handle large fluid volumes per time.

Features of a three-Phase Separator

Per a client’s requirements, three-phase separators for oil and gas can be purchased as bare vessel (standalone) systems or vessels mounted onto a skid or custom unit.

Some essential features of three-phase separators include:

  • Inlet section
  • Inlet diverter
  • Weir plates
  • Mist extractor
  • Vortex breaker
  • Defoaming plates
  • Liquid dump valve
  • Wave breaker
  • Pressure relief valves
  • Liquid outlet

How Does a Three-Phase Separator Work?

The hydrated fluid stream enters the inlet of the separator and is deflected by the inlet diverter which also reduces its momentum. This is the first (primary) stage of separation.

After passing the inlet diverter, the momentum of the fluid is reduced by the increased surface within the vessel in a second separation stage which separates the constituents into the lighter and heavier fractions, based on their specific gravities. For example, oil, a lighter constituent is separated from water, a heavier constituent.

Finally, the gaseous constituent passes into the mist extractor which removes the smaller water vapor molecules to produce dry gas. The water and oil are collected from separate outlets located on the vessel.

As earlier stated, a separator vessel can have a vertical or horizontal orientation. The vertical three-phase separator design is ideal for low gas-oil ratio (GOR) mixtures and saves space. The main horizontal separator advantages are accommodation for higher volume separation and greater efficiency in high GOR separation.

how does a 3-phase separator work?

Two-Phase Separators for Oil and Gas

A two-stage separator extracts liquids from natural gas. They are available in vertical, horizontal, and spherical configurations. Two-phase separators are extensively used in onshore or offshore oil and gas facilities and petrochemical applications. Two-phase separators are widely used for liquid-liquid or solid-liquid separation at processing facilities.

Liquid-Liquid Separators

These devices separate immiscible liquids into the individual fractions via differences in viscosity, interfacial tension, or specific gravity between liquid components.

Solid-Liquid Separators

These separators remove solid particles from liquids via centrifugation, use of semi-permeable media (e.g. filters and membranes), or settling. The principle of separation is the differences in sizes of the solid and liquid molecules of the mixture.

Features of a Two-Phase Separator

Like three-phase systems, they are available as standalone or skid-mounted systems.

Some essential features of two-phase separators include:

  • Inlet section
  • Inlet diverter
  • Mist extractor
  • Liquid dump valve
  • Level controller
  • Gravity settling section
  • Pressure relief valves
  • Gas outlet
  • Liquid outlet

How Does a Two-Phase Separator Work?

Two-stage separators have the same basic operating principle as three-phase systems but can only separate oil and gas mixtures. Like a three-phase system, it can be oriented as a horizontal two-phase separator or vertical two-phase separator. Due to their compact nature, vertical two-phase separators can only accommodate smaller volumes of fluid that require shorter residence times.

IFS Modular Process Skids Can Support Your Upstream & Midstream Needs

At Integrated Flow Solutions, we utilize two-phase and three-phase separators in our process equipment for upstream and midstream oil and gas. For example, many of IFS’s process packages include separators for oil and gas separation.

We are a best-in-class manufacturer of modular and custom-engineered pumping and process systems for oilfield operators and industrial clients in diverse industries.

To get in touch with us, please contact us online today or call us at 281-855-8125.



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