An aqueous solution of methanol is to be distilled in a tray column. High pressure steam is available as a source of heat. For a given reflux ratio and overhead composition, two options are being explored; (i) a reboiler is used and (ii) no reboiler is used but steam is fed directly to the bottom of the column. As compared to option (i), in option (ii) ____________________?

Question

Accepted Answer

Less number of trays are required. Direct steam feed at the bottom provides heat and vapor flow without liquid boil-up from a reboiler. This generally improves separation efficiency, requiring fewer trays.