What is Vacuum Distillation column

A vacuum distillation column is a type of distillation column that operates under a vacuum. This means that the pressure inside the column is lower than atmospheric pressure. The lower pressure allows the distillation of compounds that would normally boil at too high a temperature at atmospheric pressure.

Vacuum distillation columns are used in a variety of industries, including petroleum refining, chemical processing, and food and beverage production. In petroleum refining, vacuum distillation columns are used to separate heavier hydrocarbons from crude oil. In chemical processing, vacuum distillation columns are used to purify compounds for use in pharmaceuticals, plastics, and other products. Vacuum distillation columns are used in the manufacturing of food and drinks to distil alcoholic beverages and extract essential oils from plants.

The principle of vacuum distillation is based on the fact that the boiling point of a liquid decreases as the pressure decreases. This means that a compound that would normally boil at 300 degrees Celsius at atmospheric pressure will boil at a lower temperature, such as 100 degrees Celsius, under a vacuum.

A vacuum distillation column typically consists of a tall, cylindrical vessel with a heat source at the bottom. The feed material is introduced into the bottom of the column and heated. As the feed material vaporizes, the vapor rises up the column. The vapor is then condensed on a series of trays or packing material inside the column. The condensed liquid then flows down the column and is collected at the bottom.

The vacuum is created in the column by a vacuum pump. The vacuum pump removes the vapor from the column, which lowers the pressure inside the column. This allows the distillation of compounds that would normally boil at too high a temperature at atmospheric pressure.

Vacuum distillation columns are a versatile and efficient way to distill a variety of compounds. They are used in a wide range of industries, and they offer a number of advantages over other distillation methods.

How Vacuum Distillation column works

Atmospheric reside is further fractionated in a Vacuum Distillation tower. Products that exist as a liquid at atmospheric pressure will boil at a lower temperature when pressure is significantly reduced. Absolute operating pressure in a Vacuum Tower can be reduced to 20 mm of mercury or less (atmospheric pressure is 760 mm Hg). In addition, superheated steam is injected with the feed and in the tower bottom to reduce hydrocarbon partial pressure to 10 mm of mercury or less.
Vacuum Distillation column

 

Atmospheric resid is heated to approximately 750˚F (400˚C) in a fired heater and fed to the Vacuum Distillation tower where it is fractionated into light gas oil, heavy gas oil and vacuum resid.
Typical products and their true boiling points (TBP) from crude oil distillation (i.e., both atmospheric and vacuum tower products) are:
Product
Initial TBP – ˚F (˚C)
Final TBP – ˚F (˚C)
Light Naphtha
80 (27)
200 (95)
Heavy Naphtha
200 (95)
380 (195)
Kerosene
355 (180)
500 (260)
Light Gas Oil
470 (245)
650 (345)
Heavy Gas Oil
630 (330)
800 (425)
Vacuum Gas Oil
775 (410)
1000 (540)
Vacuum Resid
1000 (540)

How vacuum distillation columns are used in different industries

  • In petroleum refining, vacuum distillation columns are used to separate heavier hydrocarbons from crude oil. This is done by distilling the crude oil under a vacuum, which allows the lighter hydrocarbons to vaporize and be collected, while the heavier hydrocarbons remain in the residue.
  • In chemical processing, vacuum distillation columns are used to purify compounds for use in pharmaceuticals, plastics, and other products. This is done by distilling the compound under a vacuum, which removes impurities and allows the pure compound to be collected.
  • Vacuum distillation columns are used in the manufacturing of food and drinks to distil alcoholic beverages and extract essential oils from plants. This is done by distilling
    the plant material or the alcoholic beverage under a vacuum, which allows the essential oils or the alcohol to be collected.

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