Fractionators

Fractionators, also known as fractionating columns or distillation columns, are separation units used to divide a complex mixture into fractions with distinct boiling ranges. They are central to petroleum refining, petrochemical processing, and chemical manufacturing. The separation relies on fractional distillation: the feed is heated to produce vapor that rises through the column while liquid reflux flows downward. Light components with lower boiling points move toward the top, while heavier components collect at the bottom. The column operates at a controlled pressure; a condenser at the top and a reboiler at the bottom provide the energy and phase changes. Reflux improves separation, and product streams are withdrawn as overheads (light fractions) or bottoms (heavy fractions).

Construction and operation: Fractionators are tall vessels packed with trays or structured packing. Trays provide discrete equilibrium stages; packing increases contact area for mass transfer. The number of effective stages and the reflux ratio largely determine separation quality. Other key parameters include column diameter, feed location, and operating pressure. Materials of construction vary with process fluids, ranging from carbon steel to stainless steel or alloys.

Applications: In oil refining, fractionators split crude distillates into light and heavy fractions such as naphtha, kerosene, diesel, and heavy gas oil; vacuum fractionators handle residues. They are also used in gas processing to separate natural gas liquids and in chemical plants to purify solvents and intermediate products.