What is the function of a reboiler?

• A. To heat and partially vaporize liquid; it is the primary heat source for distillation towers.
• B. To cool the distillate before entry to the condenser.
• C. To filter impurities from the feed.
• D. To store feed for the column.

Answer: (A)

The function of a reboiler is to provide the heat input at the bottom of a distillation column, heating and partially vaporizing the liquid there to generate vapor that rises up through the column. This heat-driven vaporization is what drives the separation, creating the energy needed to achieve the different boiling point components as they move between the liquid and vapor phases inside the column. In practice, the reboiler acts as the primary energy source for the column, sustaining the necessary vapor-liquid equilibrium that allows the desired separation to occur. The overhead vapor is cooled and condensed in the condenser, not in the reboiler, and filtration or storage duties are handled by other equipment, not the reboiler.