Fraktsioneerimine

Fraktsioneerimine is a separation operation used to divide a complex mixture into fractions with narrower boiling-point ranges. In practice, it is most commonly realized through fractional distillation, though other fractionation techniques such as steam distillation or vacuum distillation are also used when necessary. The method relies on differences in volatility: components with lower boiling points vaporize at lower temperatures and rise through a distillation column, where they repeatedly condense and re-vaporize on trays or packing. Each theoretical plate improves separation, producing fractions with progressively higher boiling points as the distillation progresses. The distillate is collected as separate fractions by temperature or composition, typically via controlled reflux and cooling.

Equipment commonly includes a fractional distillation column, reboiler, condenser, feed, trays or structured packing, and a reflux drum. The process enables the production of distinct fractions from a single feed, with control over temperature profiles and reflux ratio to optimize separation.

Applications are widespread and include petroleum refining, where fraktsioneerimine yields fractions such as LPG, naphtha, kerosene, diesel, and fuel oil; chemical processing; essential-oil production; and solvent purification. Variations encompass atmospheric versus vacuum distillation, steam distillation for heat-sensitive materials, and azeotropic or entrainer-assisted distillation to overcome azeotropes.

Limitations include substantial energy requirements, reduced effectiveness for components with very similar boiling points, potential formation of azeotropes, and material or corrosion challenges in some mixtures. The technique matured in the 19th and 20th centuries and remains a fundamental method in both industry and laboratory settings.