Sizing Of Horizontal Separators

Sizing Of Horizontal Separators



A vapor-liquid separator (or knockout) drum is a vessel into which a liquid and vapor mixture (or a flashing liquid) is fed and wherein the liquid is separated by gravity, falls to the bottom of the vessel (settling), and is withdrawn. The vapor travels at a design velocity which minimizes the entrainment of any liquid droplets in the vapor as it exits the top of the vessel.

The size a vapor-liquid separator drum should be dictated by the anticipated flow rate of vapor and liquid from the process vessel. The sizing methodology implemented here involves using correlations for maximum vapor velocity factors, the Souders & Brown equation, coupled with the liquid surge capacity as described in Coker.

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The Souders-Brown equation is given as:

V = K [(ρL - ρV)/ρV]0.5

where

V = maximum allowable vapor velocity
K = vapor velocity factor
ρV = vapor density
ρL = liquid density


BIBLIOGRAPHY

• Coker, AK; Fortran Programs For Chemical Process Design, Analysis & Simulation; Gulf Publ. Co, Houston, 1995.
• Chopey, NP; Handbook of Chemical Engineering Calculations; McGraw Hill, New York, 2003.