What happens when you increase pressure in a distillation column?

When pressure increases, relative volatility between the components will decrease. This will increase reflux ratio and molar flow rates in the column, As a result, the area required for vapour flow will increase. As pressure increases, vapour density will increase.

What is the effect of atmospheric pressure on distillation?

The boiling point is reached when the vapor pressure of a liquid matches the atmospheric pressure. Raising the atmospheric pressure will raise the boiling point. Conversely, lowering the atmospheric pressure will lower the boiling point of the liquid.

Where is pressure highest in distillation column?

There is typically a pressure gradient across the column with the pressure being higher at the bottom of the column than the top. This pressure gradient occurs as the liquid coming down the column impedes the flow of vapor up the column and imposes a pressure loss on the flow.

What causes low pressure in distillation column?

This phenomenon is caused by low vapour flow. The pressure exerted by the vapour is insufficient to hold up the liquid on the tray. Weeping is indicated by a sharp pressure drop in the column and reduced separation efficiency.

What is high pressure distillation?

High pressure distillation (typically 3 – 20 atm) usually occurs in thermally integrated processes or when the normal boiling point of the vapour product is lower than the temperature of the cooling water required to condense it. Distillation is no longer possible beyond this point.

How is pressure maintained in distillation column?

If the distillate is in the liquid phase and the amount of inerts is negligible, the column pressure can be controlled by modulating the cooling water flow through the condenser (Figure 1). This reduces the rate of condensation and increases the column pressure.