In a distillation system, what is the reflux drum used for?

• A. A vessel that contains the distillate after it passes through the condenser
• B. A device that heats the feed
• C. A vent for noncondensable gases
• D. A device that measures flow rate

Answer: (A)

The main idea is that the reflux drum acts as the receiver for the condensed overhead. After the column’s vapor is cooled in the condenser, the liquid (distillate) needs a place to collect and be split. The reflux drum provides that collection point and from it you can send a portion back to the column as reflux to control separation, while the remainder goes on as the top product. It also serves as a convenient spot to manage noncondensables and maintain stable liquid level in the system. Heating the feed happens in a heater or reboiler, not in the reflux drum; venting and flow measurement are not its primary roles, though vents and sampling ports may exist.