Prediction of Vapour Velocity in Bubble-Cap Towers by Nomograph

Abstract

Bubble-cap towers are the oldest and the most versatile type of vapour — liquid contacting devices,used not only in distillation, but in gas absorption also when the relatively high resistance to gas flow is not a serious objection. Essential design features for a bubble-cap tower include the fixation of number of plates and diameter. Graphical representation of Giliand's correlation(1) is a method for a quick estimate of number of theoretical plates in a bubble-cap tower. For calculating the tower diameter it is imperative to predict correctly the vapour velocity in a tower which depends on the tray dynamics and properties of the vapour-liquid system being handled.