The primary difference between the atmospheric and vacuum distillation column is that atmospheric distillation is used to separate a mixture’s low boiling fraction. In contrast, vacuum distillation makes it easy to separate a mixture’s high boiling fraction by lowering its boiling point.
Distillation is a way to clean a liquid by heating it and then cooling it. Distillation methods like simple distillation, atmospheric distillation, steam distillation, fractional distillation, vacuum distillation, etc., are used for different things.
What is Atmospheric Distillation?
Atmospheric distillation is a way to separate the different parts of crude oil at room temperature and pressure. This method separates things whose boiling points are low (low boiling fractions).
In this process, crude oil that has already been heated to about 250-260°C is heated again to about 350°C. The heated crude oil is then sent to a distillation column, where the maximum pressure is between 1.2 and 1.5 atm.
Crude oil that has already been heated and de-salted is fed into the atmospheric distillation process. Small hydrocarbons like fuel gases, kerosene, naphtha, fuel oil, and diesel are divided by this distillation process. The heavy hydrocarbon fraction is left at the base of the atmospheric distillation column. This part of the mixture goes to the vacuum distillation.
What is Vacuum Distillation?
Vacuum distillation is a way to separate parts of a mixture when the pressure is low. This method is used when the boiling points of the mixture’s parts are hard to reach or when higher temperatures cause the compounds to break down instead of boiling off. Because the pressure is lower, the boiling point of the parts is lower than usual.
In large-scale industrial distillation, many stages of distillation are used to separate the essential parts of a mixture. When things are like this, it’s better to use a vacuum distillation column. This method makes the parts of a mix more volatile than each other (the relative volatility is the difference between the boiling points of two components). When the relative volatility is increased, it is easier to tell the different parts apart.
A significant benefit of vacuum distillation over other methods is that it only needs to be done at low temperatures. This is because the boiling points are lower when the pressure is low. Another important thing about this method is that it keeps essential parts from breaking down at high temperatures. And with this method of distillation, both the yield and the purity are better.
What’s the Difference between Vacuum Distillation and Atmospheric Distillation?
Atmospheric distillation uses pressure almost the same as the atmosphere’s (around 1.2-1.5 atm). In vacuum distillation, the pressure is shallow.
Atmospheric distillation separates the parts of a mixture that don’t boil very high. By lowering the boiling point of a high boiling fraction, vacuum distillation makes it easy to separate the parts.
The delicate part of a mixture is separated by atmospheric distillation. The heavy part of a mixture is separated by vacuum distillation.
Distillation is repeatedly cooling and heating a mixture used by the equipment fabricators to separate its different parts. Distillation can be done in two different ways: in the air or in a vacuum. The difference between atmospheric and vacuum distillation separates a mixture’s low boiling fraction. In contrast, vacuum distillation makes it easy to separate a mixture’s high boiling fraction by lowering its boiling point.