Which description best captures the reboiler's role in a distillation tower?

• A. To heat and partially vaporize liquid; it is the primary heat source for distillation towers.
• B. To condense vapor from the column overhead.
• C. To remove impurities from the feed stream.
• D. To store feed for the next batch.

Answer: (A)

The reboiler’s job is to provide the heat at the bottom of the distillation column, turning part of the bottom liquid into vapor that rises up through the column. This boils the bottom section and creates the vapor flow that drives the separation, setting the boil-up rate and supplying the primary energy for the distillation process. It’s not responsible for condensing overhead vapor (that’s the condenser), nor for removing impurities or storing feed. In practice, the reboiler often uses steam or hot oil to heat the bottom liquid, sustaining the column’s continuous separation.