Vapor Inlet Device

The Vapor Inlet Device (VID) is generally required whenever a very high-velocity or unevenly distributed vapor flow is anticipated. The purpose of VID is to decrease the momentum of the vapor feed and evenly distribute the gas across the vessel cross section. The same is obtained by dividing the feed mixture into horizontal streams. This reduces the vertical vapor velocity within a short distance of its discharge into the tower.

Typically it is located in the bottom section of the column where reboiler feed is entering the tower or between the tray and packing section. Kinetic energy of the inlet vapor and the vapor fraction, must be considered while designing these devices.

The installation is generally in horizontal inlets in a vertical column.