What is dew point? State its importance on designing a distillation column?
The dew point is the temperature and pressure at which a substance such as water turns from a gas to liquid. In the design of a distillation column that has several trays, the mixture must reach an equilibrium on each tray. So if the column is working right, then the mixture should have a different composition on each tray. A tray can be treated as a single distillation unit where the gas goes off of the top and liquid goes down. This means that liquid is always entering the container from the top while gas is always going up. This is called reflux. Over time the composition of the gas and the liquid on each tray will reach constant concentrations. But for the distillation column to work they must be different. The dew point may also be thought of as the gas saturation point. This is what you want the gas leaving a tray to be at for minimum energy input operation. If this doesn’t help then you can take the mass transfer operations class that Chemical Engineers take. I just “loved” that
