Ethanol (Ethyl Alcohol) is converted to Acetaldehyde by vapour phase reaction. The reaction is a combination of oxidation & dehydrogenation.
Ethyl Alcohol vapours mixed with air are passed over Silver Catalyst maintained at 450°C – 500°C in a plug flow Reactor. The reaction products are condensed. Uncondensed gases are sent to two scrubbers in series to recover Aldehyde and Alcohol. The condensate and the absorbate thus obtained is sent to a Distillation Column to obtain pure aldehyde product from the top. The bottom consisting of Alcohol - Water mixture is passed through Reactor tubes in order to recover the heat of reaction. The vapours formed are sent to the Aldehyde Distillation Column and the overflow liquid is sent to another Distillation Column to recover unconverted alcohol which is in turn recycled through Carburettor.
The process is operated at elevated pressure so as to increase the boiling point of acetaldehyde and thereby the necessity of using chilled water for Aldehyde condensers is eliminated.
The product Acetaldehyde is stored under inert gas N2 blanket.
