Liquid phase oxidation of butane for manufacturing of acetic acid
Acetic acid production done when butane heated with oxygen in the presence of metal content catalysts mainly,manganese, cobalt and chromium ions based in a sparged tower. Along with recycle streams butane is pumped to the bottom of the sparged tower and oxygen is fed through the sparger present in bottom section of the tower. Catalyst is recycled along with the process material through the heat exchanger and maintains the reaction temperature. Product is withdrawn from the top of the sparged tower and pressure is dropped down using a turbine expander. Depressurized product stream is fed to a separator where the unreacted butane is separated from the top and recycled to the reaction tower.
Peroxide, ethanol, acetone (due to isobutene present in feed as impurity) are the Intermediates formed in the process and by the layer separator hydrocarbon layer is sent back to the sparged tower for reaction. The bottom aqueous layer contains by-products ethyl acetate, methyl acetate, butanone and other compounds : Formic acid, butyric acid and propionic acid along with acetic acid are sent to the purification section.
Ethyl acetate, methyl acetate are removed initially using a light end distillation column. The bottom stream is sent to the acetic acid tower to separate the heavy ends like propionic acid and butyric acid. Acetic acid from top of the acetic acid tower is send to purifier to remove the formic acid azeotrope.