Figure 2-31. Pipe Furnaces.
The oil is then discharged into the fractionator (also
called fractionating column or distilling unit). The pressure is suddenly released
and it flashes into a mixture of vapors. Cold gasoline (gasoline reflux) is piped
into the top of the tower, cooling it and thus creating a temperature gradient:
very hot at the bottom and growing cooler closer to the top. Specific hydrocarbons
will condense out as they rise to a level with a temperature corresponding to their
They can then be piped out of the distilling unit for further
processing. The typical fractionator is a tall, steel tower filled with perforated
steel trays dividing it into sections (Figure 2-32). Gases can pass up through the
perforations and the bubble caps, but the raised rims inside the bubble caps
prevent condensed liquids from draining back down.
Petroleum Fractionating Columns.
45 IT 0673