The bubble plate type fractionating column is shown in the figure. The tower is divided into number of compartments by mean as of shelves having openings. The openings are covered with caps called bubble caps. Each shelf is provided with an overflow pipe which keeps the liquid to a certain level and then allows the rest to trickle down to the lower shelf. Such type of column is used for continuous separation of bulk quantities of liquids, e.g., distillation of fermented liquid for manufacture of rectified spirit.
(i) Separation of crude oil in petroleum industry into various useful fractions such as gasoline, kerosene
oil, diesel oil, lubricating oil, etc.
(ii) Separation of acetone and methanol from pyroligneous acid obtained by destructive distillation of