lowest vacuum achievable in a vacuum distillation column

[diapensiya]

I want to separate two high boiling point components from each other. (Atmospheric Boiling points 250-300C vs 300-500 C)
Thus, I need deep vacuum. I investigate the option of using a traditional vacuum distillation unit followed by an evaporator. (There are other options I am investigating as well but my question is around this one)
Evaporators (short path) can go less than 1 mbara vacuum. For typical distillation unit, I have seen vacuums as low as 100 mbara.
Does anyone know what is the lowest vacuum achievable in a typical distillation column?

 

[EmmanuelTop]

Typical vacuum distillation units in petroleum refineries operate between 10-50 mbara absolute pressure (950-980 mbar vacuum) on the column top. There are industrial units designed and operating with less than 1 mbar absolute pressure. Google GEA Jet and Graham-MFG. They have a lot of great articles on vacuum.

http://www.graham-mfg.com/technical-documents-library/vacuum-equipment

http://www.gea.com/en/binaries/ejector-vacuum-pump-steam-gea_tcm11-34892.pdf

Dejan IVANOVIC
Process Engineer, MSChE