Trays, packing, downcomers, weirs, vapour holders, liquid traps, drain plugs, supporting frames, liquid distributor, splitter, vapour distributor etc, are some of the parts and accessories fitted inside of an industrial distillation column, the model shows only an ideal set up which is not similar or identical all types of distillation column available in the manufacturing industry but to know what it actually have for conducting distillation operation on large and small scale. Based on vapour –liquid equilibrium data of the mixture which may be in vapour or in liquid phase, a distillation column equipment is designed to obtain a desired separation.
Without any calculations and equations lets know as rule of thumb what does distillation column equipment contains in it and what do each item could help to obtain a distillation operation with illustration. Let’s imagine a binary mixture in liquid phase has two components and if they are required to be separated into individual pure component if in case they have vast difference in boiling points so that we put it in vessel and heat it so that a temperature where it meant one component boiling point than the liquid produce vapour and these vapours rise up ward. Which in case of a column filled with mixture at it bottom vessel and supplied with enough heat by means of steam than the vapours will be generated and move in upward direction.
A series of plates are fitted from bottom have perforated holes in them some have valves and bubble caps. The vapours penetrate through these holes and reach a feed plate where we can supply continuous liquid mixture into column. The liquid from feed plate due to gravity and density flow on to the down section of tray through the trays and over flow into down-comer which act as channel between trays and help the liquid to stay on the tray for desired duration.
Each plate if fitted on frame supports having a manhole section. Feed plate has a liquid distributor to spread the liquid evenly to avoid the condition of dryness. Above feed plate liquid collector maintains the liquid continuous flow toward bottom of the column from the top section where the vapour is condensed to liquid and a part of it is sent back to the column to prevent other component which has high boiling point value from carry over the top section are usually filled with packing than a trays. Based on the packing material and packing types the mass transfer will be enhanced. Combination of packing and tray improve the performance of a distillation column equipment. Above the packing a liquid distributor is fitted to make the liquid flow all over the packing.
A model shows a distillation column equipment combined system which is designed with packing and tray inside it which is an optimized from packed and tray column.
Distillation column equipment cross section diagram: