Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure (usually less than atmospheric pressure) causing evaporation of the most volatile liquid(s) (those with the lowest boiling point).This distillation method works on the principle that boiling occurs when the vapor pressure of a liquid exceeds the ambient pressure. Vacuum distillation is used with or without heating the mixture.
Vacuum Pressure Ranges
Gentle thermal separation of liquid mixtures largely preserves the physical and chemical integrity of the relevant ingredients. It can be accomplished with a reduction of boiling temperatures. This, in turn, can conveniently be accomplished via a reduction of pressure.
A broad portfolio of vacuum pump types and sophisticated designs of pump sets are available to effectuate such vacuum conditions. Vacuum pressure ranges are usually subdivided into the intervals depicted in the adjacent diagram.
Typical pressures applied for vacuum distillation are in the fine vacuum range, i.e., between 1 mbar and 10-3 mbar. Corresponding mean free path lengths are in the centimeter range.
Pumps, Pump Sets
Vacuum pumps for the intended pressure range are gas transfer pumps of the “positive displacement” or the “momentum transfer” category. Characteristic parameters that determine the suitability of a pump type for a given task include:
Suction capacity, speed
Inlet and exit pressure
In EVP Company you will preferably find the following vacuum pumps in various sizes and performance categories:
Liquid Ring Pump Rotary Vane Pump Steam Ejector Pump Oil Diffusion Pump
The design of an effective vacuum system for a plant requires a diligent and thorough analysis of the performance criteria including technical and commercial constraints. This includes the selection and combination of pump types and sizes as well as the piping of the vacuum systems. Below you may find some examples of pump sets for different vacuum ranges.
1.Roots Vacuum Pump with Cold Trap Pump
2.Liquid Ring Vacuum Pump
3.Rotary Vane Vacuum Pump combined with Oil Diffusion Vacuum Pumps.