Souders–Brown equation

In chemical engineering, the Souders–Brown equation (named after Mott Souders and George Granger Brown[1][2]) has been a tool for obtaining the maximum allowable vapor velocity in vapor–liquid separation vessels (variously called flash drums, knockout drums, knockout pots, compressor suction drums and compressor inlet drums).

The following sizing methodology is based on the assumption that those flow rates are known.

Use a vertical pressure vessel with a length–diameter ratio of about 3 to 4, and size the vessel to provide about 5 minutes of liquid inventory between the normal liquid level and the bottom of the vessel (with the normal liquid level being somewhat below the feed inlet).

Calculate the maximum allowable vapor velocity in the vessel by using the Souders–Brown equation:

As for the mechanical design of the drum (materials of construction, wall thickness, corrosion allowance, etc.)

The GPSA Engineering Data Book[3] recommends the following k values for vertical drums with horizontal mesh pads (at the denoted operating pressures): GPSA notes: