Covestro Deutschland Ag

Covestro Intellectual Property Gmbh & Co. Kg

Jürgen Bausa

Jörg Hofmann

Friedhelm Steffens

Bernd Pennemann

Kai Laemmerhold

Volker Michele

Matthias Wohak

Wilfried Hedderich

Stefanie Braun

Franz Beggel

Cyrus Ahmadzade-Youssefi

The invention relates to a cascade tray suitable for use in a rectifying column and comprising openings in the weir-type cascade edge, to a rectifying column containing at least one cascade tray according to the invention, to a method for operating such a rectifying column, and to the use of a claimed rectifying column in the fractionation of specific substance mixtures.

Cascade tray, rectifying column containing said cascade tray, method for operating such a rectifying column, and use of same

A distillation column for separating a multicomponent mixture into at least three fractions. The distillation column has at least one separating wall and at least one material exchange element () above the at least one separating wall. A device () for mixing the steam flows flowing upwards to the left and the right of the at least one separating wall is arranged between the at least one separating wall and the at least one material exchange element (). The use of the distillation column for purifying isocyanates, in particular for toluene diisocyanate (TDI), is also described.

Distillation column and use thereof for cleaning isocyanates

The present invention relates to a purifying apparatus for polycarbonate polyols, especially for removal of cyclic alkylene carbonates, comprising an evaporation unit () provided with a heater () and having an inlet () disposed at the top end thereof and a bottoms vessel (), and a stripping column () connected downstream of the evaporation unit () and having a top () and a bottom (), wherein a feed () for the polycarbonate polyol to be purified opens into the inlet () to the evaporation unit () and a gas outlet line () and a connecting line which opens into the top () of the stripping column () and is equipped with a pump () depart from the evaporation unit (), and wherein a gas inlet line () for an inert gas opens into the bottom () of the stripping column () and a product line () for the purified polycarbonate polyol departs from the bottom () of the stripping column () and a gas outlet line () departs from the top () of the stripping column (). The invention additionally relates to a process for purifying polycarbonate polyols with such a purifying apparatus.

Process for purifying polycarbonate polyols and purifying apparatus therefor

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Kürten, Germany

Jürgen Bausa