Two/Three Phase Oil & Gas Separation

              Factors Affecting Separation

  1. Fluid inflow rates
  2. Operating temperatures and pressures
  3. Surge/Slug and foaming tendencies
  4. Inflow fluid properties
  5. Design parameters
  6. Inflow fluid impurities
  7. Corrosive tendencies of fluids

              Principles of Separation

  • Centrifugal inlet to provide primary separation of liquid and gas
  • Adequate dimensions/volume characteristics to promote settling and provide surge room
  • Mist extractor/eliminator to coalesce small particles of liquid
  • Provides adequate level control and instrumentation to properly monitor and manipulate fluid volumes/levels within the device and to allow for SAFE operation.

              Gas Liquid Separation

The most important duty of fluid processing. A properly designed separator must:

  1. Primary phase separation of liquid hydrocarbons
  2. Refine the primary separation by removing entrained liquid
  3. Further refine separation by removing entrained gas from liquid
  4. Dis-charge the separated fluid gas/liquid streams in such a manner that NO RE-ENTRAINMENT occurs.

              The Separator

This is critical component in the separation process, one that does the bulk work of handling and sorting the well-stream fluids.

   Components

        Inlet Diverter

Reduces the inlet momentum aiding in phase separation at the inlet stage. It can be considered the primary separation.

        Fluid Collection

Usually the lower section of the vessel that provides the volume necessary to promote fluid accumulation and retention time.

        Settling Section

This section promotes further settling by gravity.

        Mist Extraction

This is located at the gas phase output, the mist extractor helps with the coalescing of small droplets of fluid still entrained in the gas phase and allows for it to rejoin the liquid phase.

              Sizing a Separator

   Vertical Separator

  1. Calculate CD
  2. Iterate to find Vt, Re and CD. Stop when values converge.
  3. Calculate Gas Capacity Constraint
  4. Calculate the Liquid Capacity Constraint
  5. Compute values for diameter and height for various residence times
  6. Compute the seam to seam length
  7. Compute slenderness ratio
  8. Choose a reasonable size with a diameter greater then gas capacity constraint.

   Horizontal Separator

  1. Calculate CD
  2. Iterate to find Vt, Re and CD. Stop when values converge.
  3. Calculate Gas Capacity Constraint
  4. Calculate the Liquid Capacity Constraint
  5. Compute values for diameter and height for various residence times
  6. Compute the seam to seam length
  7. Compute slenderness ratio
  8. Choose a reasonable size with a diameter greater then gas capacity constraint.
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