Fractional Distillation

The process of separating a mixture into various component parts or into various fractions or into various components, parts or into various fractions is referred to as fractional distillation. This is done by raising their boiling point by heating them up to a certain temperature which will lead to the evaporation of several fractions. Fractional distillation is a special type of distillation where the component parts boil at less than 25 °C under pressure. Simple distillation is used if the boiling point goes above 25 °C.

Distillation of ethanol:

For instance, consider the distillation of the ethanol and water. The boiling point of water is 100 °C and the boiling point of ethanol is 78.4 °C. Through direct fractional distillation method with the ethanol-water mixtures the ethanol cannot be completely purified. A mixture of 96% of ethanol and 4% of water would be boiling at about 78.2 °C which is more unpredictable than the pure ethanol. While heating the mixture, the component that is most volatile will concentrate to a greater extent while leaving the liquid.

Continuous state:

In the petroleum refineries, chemical plants, cryogenic air separation plants, and natural gas processing distillation is the common form which is used in the separation technology. The fractional distillation process is carried out in a continuous state in most cases. To the distillation column, there are some new feed which are always added while some products are being removed. The amount of the feed that are added and the amount of the product that are being removed is normally equal until the process is disturbed as a result of some changes in the ambient temperature, heat, amount of condensing or the feed. This state is referred to as continuous steady state fractional distillation.

Distillation columns:

Usually, the distillation columns or the large distillation or fractionation towers are the vertical cylindrical columns in which industrial distillation is performed. The height of these cylinders ranges from 6 meters to about 60 meters and the diameter of these towers range between 65 centimetres to 6 meters. The liquid outlets that are present in these distillation towers at regular intervals allow the withdrawal of the fraction or the products at different boiling ranges and boiling points.

Along with some other anti-bumping granules the mixture is put in the round bottomed flask. The fractional distillation is used in the liquid nitrogen, liquid oxygen, and highly concentrated argon and in air separation. Instead of trays a packing material is used in here sometimes during the industrial usage. The packing material can be a random dumped packing or it can be structure sheet metal.

Questions:

• What is fractional distillation?
• What is simple distillation?