5 replies to this topic

[vijji]

Hi friends,
Atmospheric distillation or vacuum distillation which one is faster and how?

[Fr3dd]

I don't think this question makes any sense. Distillation is a process to separate a mixture based in the difference of volatility of its components. Atmospheric distillation will allow you to separate components with boiling temperatures manageable at atmospheric pressures and Vacuum distillation will allow you to lower the boiling point of components of the mixtures with high boiling temperatures at atmospheric pressure (by decreasing the pressure).

I don't think "speed" is relevant here.

[Art Montemayor]

Fr3dd is precisely correct. This query is assuming there is a question of which is "better", "faster", or "superior".

The choice between both types of distillation is based on what is more appropriate and suits the requirements detailed in the scope of design. Some distillation scopes may not allow for a temperature beyond a certain ceiling - which may call for vacuum operation. Others may not be affected by temperatures, but rather by total capital investment capital.

[kkala]

Let us have a simplified example of above useful explanations. In a simple refinery you treat the crude in the atmospheric distillation column and you sell the bottom product, e.g. as heavy fuel oil (straight run atmospheric residue). In a modern refinery you pass the heavy bottom product of atmospheric column into the vacuum distillation column to obtain vacuum gasoil (further treated and added to fuels) and e.g. asphalt. See http://en.wikipedia.org/wiki/Oil_refinery.
So this additional distillation under vacuum results globally in more light products and less bottom residue, desirable due to present low demand of heavy products.
(http://www.cheresour...ersion-refinery '> http://www.cheresour...ersion-refinery .

Edited by kkala, 22 August 2012 - 11:57 AM.

[vijji]

Hi all, assume i have taken 3000 Lts of the methanol in reactor and started distillation under atmospherically and under vacuum, which one will give fast distillate rate (Lts/hr) and how?

Edited by dsreenivasareddy123, 27 August 2012 - 10:37 AM.

[TS1979]

As the previous responses said, your query doesn't make sense. The distillation rate is not determined by the distillation pressure. It is determined by the net duty you supply to the system. The higher efficient duty you apply to the system, the higher distillation rate.