Basf Aktiengesellschaft

Basf Se Corporation

Klaus Kindler

Bernd Heida

Gerd Kaibel

Thomas Hill

Till Adrian

Gerd Bohner

Melanie Pahl

Hubert Puhl

In a continuous process for fractionating a Cfraction (C) by extractive distillation using a selective solvent (LM) in an extractive distillation column (EDK), it is proposed that a dividing wall (TW) is installed in the longitudinal direction in the extractive distillation column (EDK) to form a first region (A), a second region (B) and a lower combined column region (C) and a top stream (CH) comprising the butanes is taken off from the first region (A), a top stream (CH) comprising the butenes is taken off from the second region (B) and a stream (CH) comprising the hydrocarbons from the Cfraction which are more soluble in the selective solvent (LM) than are the butanes and the butenes is taken off from the lower combined column region (C).

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A continuous process for isolating butenes from a Cfraction comprising butanes, butenes and other C-C-hydrocarbons by extractive distillation using a selective solvent (LM), comprising a first process stage I in a scrubbing zone (E) and a second process stage II in a degassing zone (A), wherein the liquid or a substream of the liquid is taken off from the degassing zone (A) at a theoretical plate located one or more theoretical plates below the feed point for the bottom stream (LM/CH) from the scrubbing zone (E), heated and/or vaporized by indirect heat exchange with the hot bottom stream (LM) from the degassing zone (A) and returned to the degassing zone (A) at the same theoretical plate or above this, with the theoretical plate from which the liquid or substream of liquid is taken off being selected so that the total energy requirement in the process stages I and II is minimized, is proposed.

Sudstituted the abstract with a new abstract as follows: The invention relates to a continuous process for separation a mixture of hydrocarbons which has beenobtained by extractive distillation of Cfraction useing a selective solvent and the hydrocarbons from the fraction Cwhich are more readily soluble in the selective solvent than are the butanes and the butenes. The mixture is fed into a first distillation column in which it is separated into a steam which is taken off at the top and comprises 1,3-butadiene, propyne, possibly further low boilers and possibly water and a bottom stream comprising 1,3-butadiene, 1,2-butadiene, acetylenes and possibly further high boilers, with the proportion of 1,3-butadiene in the bottom stream from the distillatin column being regulated in such a way that it is at least sufficiently high to dilute the acetylenes to outside the range in which there is a risk of spontaneous decomposition. The stream taken off from the top of the first distillation column is fed to a second distillation column and is separated into a steam which is taken off at the top and comprises propyne, possibly further low boilers and possibly water and a bottom stream comprising pure 1,3-butadiene in the second distillation column.

Method for working up crude 1,3-butadiene

A process for recovering crude 1,3-butadiene from a Cfraction by extractive distillation using a selective solvent in a dividing wall column (TK) in which a dividing wall (T) is arranged in the longitudinal direction of the column to form a first subregion (A), a second subregion (B) and a lower common column region (C) and which is preceded by an extractive scrubbing column (K) is proposed.

A process for obtaining pure 1,3-butadiene from crude 1,3-butadiene by distillation is carried out in a dividing wall column in which a dividing wall is located in the longitudinal direction of the column to form an upper common column region, a lower common column region, a feed section and an offtake section.

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Harthausen, Germany

Klaus Kindler