Atmospheric Distillation vs. Vacuum Distillation — What's the Difference?

Atmospheric Distillation is a process that takes place at the pressure of the surrounding environment. This standard method separates liquids or components based on their respective boiling points under ambient pressure. One common application is the primary distillation of crude oil in refineries. On the other hand, Vacuum Distillation is conducted under reduced pressure conditions. The major advantage here is that by reducing the pressure, the boiling points of the compounds are also lowered. This means that substances which might decompose or react at higher temperatures can be distilled without any damage.

In Atmospheric Distillation, components that have boiling points below the atmospheric pressure are typically separated. It's more suited for compounds that don't degrade at higher temperatures. Conversely, Vacuum Distillation is particularly beneficial for purifying or isolating compounds that are thermally unstable. The reduction in pressure effectively allows for distillation at lower temperatures.

Furthermore, Atmospheric Distillation is frequently used for refining processes, especially in the petrochemical industry. Here, the crude oil undergoes initial distillation to separate into various fractions. Vacuum Distillation, meanwhile, finds its application in the pharmaceutical industry, laboratories, and situations where delicate compounds need to be separated.

Another distinction is the equipment. The setups for both methods differ, primarily because Vacuum Distillation requires a system that can maintain and control the reduced pressure, like a vacuum pump. In contrast, Atmospheric Distillation systems are generally simpler since they operate under regular pressure.