Horizontal Gas-Liquid Separator Sizing

Calculate the main dimensions for a horizontal gas-liquid separator.

Horizontal Separator Sizing Calculator Guide (PDF)

This calculator is used to size horizontal gas-liquid separators such as knock-out drums. The calculator determines the vessel diameter and length required to achieve the specified separation. The calculation method is based on the procedure described in "Rules of Thumb for Chemical Engineers" by Carl Branan.

The calculator automatically calculates the Souders-Brown separator sizing factor based on the specified liquid and gas flow rates and densities.

  1. Enter the mass flow rate of liquid entering the separator
  2. Enter the mass flow rate of gas or vapour entering the separator
  3. Enter the density of the liquid entering the separator
  4. Enter the density of the gas or vapour entering the separator
  5. Enter the required liquid hold-up time the separator must provide. Typical values are:
    • Tower reflux drums: 5 - 10 mins
    • Knock-out drums: 5 mins
    • Fractionation feed surge tanks: 8 - 15 mins
  6. Click the "Calculate" button
  7. The calculator will determine the separator vessel diameter, tan-to-tan length and length to diameter ratio
  8. The calculator will also determine the gas and liquid volumetric flow rates to the vessel, the separator sizing factor and associated parameters
Horizontal Separator Diagram
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INPUTS
Liquid flow rate ml
Vapour flow rate mv
Liquid density ρl
Vapour density ρv
Liquid hold-up time τl
OUTPUTS
Liquid volumetric flow rate Ql 3.50
Vapour volumetric flow rate Qv 800.00
Mixture density ρmix 5.60
Separation factor Sf 0.1237
Separator sizing factor K 0.1528
Maximum vapour velocity uvapmax 4.320
Minimum gas flow area Avmin 0.05144
Minimum separator area required Atotalmin 0.25721
Minimum separator diameter Dmin 0.572
Maximum inlet nozzle velocity unozmax 51.54
Minimum inlet nozzle velocity unozmin 30.93
Maximum inlet nozzle diameter dinlet max 0.096
Recommended inlet nozzle size dinlet 4 inch
Liquid hold-up volume Vl 0.583
Vessel length tan to tan L 2.579
Recommended separator diameter Dsep 0.600
Vessel L:D L:D 4.30
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