Optional Components

Several functional components are available in order to customize and optimize a production plant for a specific application and specific performance targets.

Degasser

Feed materials may often contain considerable quantities of dissolved gases. These may have been absorbed from atmospheric air or from inertgas blanketing. During distillation such dissolved gases will have a severe impact on distillation performance: When released under fine vacuum conditions they will occupy enormous volumes. The volume increase will roughly scale with the reciprocal pressure decrease (Boyle-Marriot). In addition, these gases are not condensable under reasonable conditions. Hence, they must be evacuated with the vacuum system which generates a tremendous performance issue.

A very effective and convenient solution for this problem is to place a degasser before the distillation unit. A degasser is a cylindrical device filled with a structured package that provides a huge surface. The preheated feed material is fed into the degasser and dispersed on the structured package. The dissolved gases will evaporate and are evacuated by the vacuum system. Since this can be accomplished at only slightly reduced pressure (rough vacuum), the corresponding volumes are manageable. The released gases may then either be condensed in a cold trap or transferred to the atmosphere.

If the separation factor of the dissolved gas and the valuable component in the feed is too small, it may be an option to place a partial condenser above the package.

For even more challenging degassing tasks it may even be an option to use a falling film evaporator or a thinfilm evaporator as a degasser.

Washing Condenser

For applications where the residue is the valuable product, an optimization of the distillation process implies stripping to very low residue contents. Distillate fractions may become very low (< 1%). In a shortpath distillation unit this will result in a considerable decrease of the concentration gradient between the material on the evaporator and the material on the condenser as the film propagates downwards from the feed entry level.

This, in turn, will result in a corresponding reduction of the vapour pressure gradient between the evaporator and the condenser. This pressure gradient, however, is the driving force for distillation to happen. If the pressure gradient vanishes, no mass transportation will occur.

This problem can be remedied with the patented washing condenser from UIC: Continuously diluting the distillate film on the condenser will reduce the concentration and hence the vapour pressure on the condenser. Compared to established approaches where a specific dilutor liquid is applied, UIC's approach may also use feed material or any inert low volatile fluid for dilution.

A prime scenario for the successful application of this technology is the removal of Persistent Organic Pollutants (POPs) from crude fishoil.

Rectification Insert

Rectification is an established approach to boost separation efficiency via repeated evaporation-condensation cycles. Each cycle yields a better separation of distillate and residue.

Rectification is routinely realized with rectification columns where a packing material with a large surface forces iterated evaporation-condensation cycles and consequently produces a vertical concentration gradient of the involved components.

For constructive reasons, this methodology has not been readily available for shortpath distillation units. Since 2008, however, our partner company VTU Engineering has been awarded a patent for a rectification insert for shortpath distillation devices, which is exclusively marketed by UIC.

It consist of a cylindrical insert which is filled with a special package. It is positioned halfway between evaporator and condenser of a shortpath distillation unit. Its benefits include

• improved separation of distillate and residue
• mechanical barrier for entrainment, i.e., avoidance of direct transfer of feed material to the condenser via splashing
• no necessity for additional (external) rectification columns

This technology has proven particularly successful in the area of Biodiesel distillation.