US 3,944,483 AGranted

Distillative recovery of aromatics with water addition in azeotropic proportions

AssigneeKrupp-Koppers GmbH

InventorsFritz Schwall, Gerhard Preusser, Martin Schulze

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Abstract

A hydrocarbon mixture consisting of an aromatic and a non-aromatic component is subjected to a liquid-liquid extraction and/or an extractive distillation. A solvent is used which selectively dissolves the aromatic component so as to form an extract phase. The extract phase is introduced into a distillation column for separating the solvent and the aromatic component. The column is provided with trays and the extract phase is introduced into the column at about the middle thereof from where the solvent flows downwardly and the aromatic component flows upwardly. Sufficient water is introduced into the sump of the column to insure that the trays above the location at which the extract phase enters the column are filled with water during the separation. This improves the operation of the distillation column. An arrangement for carrying out the above process is also disclosed.

Claims14

Dependent claims

In a process for the recovery of aromatic hydrocarbons from mixtures which contain aromatic and non-aromatic hydrocarbons, comprising subjecting a mixture which includes an aromatic and a non-aromatic hydrocarbon to extractive treatment with a water-containing solvent so as to form an extract phase which contains at least part of said solvent and at least a portion of said aromatic hydrocarbon;

admitting at least a portion of said extract phase into a distillation zone having an upper and a lower end portion;
distilling said extract phase in said zone for recovery of said portion of said aromatic hydrocarbon;
and introducing into said lower end portion of said zone a quantity of water, the improvement consisting essentially of, providing said quantity of water in an amount which equals between about 60 and 100 percent by weight of the amount of water required to form an azeotrope with said portion of said aromatic hydrocarbon, said quantity of water being additional to the water contained in said extract phase.

Dependencies are inferred from the claim text.