Basf Aktiengesellschaft

Basf Se Corporation

Bernd Heida

Klaus Kindler

Ulrich Hammon

Gerd Kaibel

Leopold Hupfer

Randolf Hugo

Thomas Hill

Till Adrian

Fritz Graf

Tobias Keller

Jan-Oliver Weidert

Gerhard Wickenhaeuser

Ortmund Lang

Norbert Asprion

Regina Vogelsang

Albrecht Dams

Peter Renze

Uwe Stabel

Fritz Thiessen

Roland Kessinger

Lembit Tuttelberg

Harry Zachmann

Eberhardt Gaffron

Michael Jäger

Julia Hofinger

Gerhard Schäfer

Process for isolating pure 1,3-butadiene from a crude Cfraction by extractive distillation using a selective solvent, wherein (a) the crude Cfraction is introduced into a predistillation column, a first low boiler fraction comprising C-hydrocarbons is taken off as overhead stream, a gaseous Cfraction is taken off as side stream and a first high boiler fraction is taken off as bottom stream, (b) the gaseous Cfraction is brought into contact with a selective solvent in at least one extraction column, giving an overhead fraction comprising butanes and butenes and a bottom fraction comprising 1,3-butadiene and selective solvent, (c) crude 1,3-butadiene is desorbed from the bottom fraction in at least one stripping column, with a stripped selective solvent being obtained and the stripped selective solvent being recirculated to the extraction column, and (d) at least part of the crude 1-3-butadiene is fed to a pure distillation column and a second high boiler fraction is separated off and a gaseous purge stream is taken off. Gaseous purge streams from the columns which are necessary in order to keep the concentration of molecular oxygen below a predetermined concentration limit are consolidated with output streams which are in any case provided for discharging other components in the process. The recirculation of the second high boiler fraction to a lower section of the predistillation column creates a further degree of freedom in operation of the pure distillation column.

Method for obtaining pure 1,3-butadiene

A process for isolating pure 1,3-butadiene from a crude Cfraction, which produces pure 1,3-butadiene having a prescribed maximum content of at least one low boiler and a prescribed maximum content of 1,2-butadiene, in each case based on 1,3-butadiene, wherein (a) a low boiler fraction and a high boiler fraction are separated off by distillation from the crude Cfraction, giving a purified Cfraction whose content of the at least one low boiler, based on 1,3-butadiene, is equal to or lower than the prescribed maximum content of the at least one low boiler and whose content of 1,2-butadiene, based on 1,3-butadiene, is equal to or lower than the prescribed maximum content of 1,2-butadiene; (b) the purified Cfraction is subjected to at least one extractive distillation using a selective solvent, giving at least a fraction comprising butanes and butenes and a pure 1,3-butadiene fraction, is described. The process makes a pure distillation column dispensable.

Simplified process for isolating pure 1,3-butadiene

A distillation device comprising a column for separating a feed stream into a head product stream, a bottom product stream and optionally one or more side extraction streams, having three or more cells in 5 series through which fluid flows, wherein at least the first cell is integrated into the bottom of the column, for multi-stage heating and partial evaporation of the liquid flowing through the cells with the exception of the liquid from the last cell in an evaporation stage.

Distillation device comprising a column which as three or a plurality of cells in series through which fluid flows and method for distilling or extractive distillation by use of the distillation device

What is proposed is a column (K) comprising separatory internals (E) for separating a mixture of hydrocarbons and/or hydrocarbon derivatives () by extractive distillation with a selective solvent (), with supply of the selective solvent () in the upper region of the column and supply of the mixture of hydrocarbons and/or hydrocarbon derivatives to be separated () below the supply of the selective solvent (), the selective solvent () becoming laden in the column (K) with the components from the mixture to be separated () for which it has greater affinity and being withdrawn from the lower region of the column as laden selective solvent (),while, by contrast, the components from the mixture to be separated for which the selective solvent () has a lower affinity remain in the vapor phase and are withdrawn as top stream (),which is completely or partially condensed to obtain a condensate (),some of which is withdrawn as product stream (), the remainder being reintroduced to the column (K) as reflux (),wherein

Column with separative installations for separating a mixture of hydrocarbons and/or hydrocarbon derivatives by means of an extractive distillation using a selective solvent

Mixtures of hydrocarbons predominantly having 4 carbon atoms per molecule known as Ccuts are used in obtaining crude 1,3-butadiene by a thermal cracking process. Vaporous purified crude Ccuts are produced from liquid crude Ccuts, containing butanes, butenes, 1,3-butadiene, Chydrocarbons, Coligomers and polymers, and Chydrocarbons via an extractive distillation by fist removing the Coligomers and polymers and the Chydrocarbons and then vaporizing the liquid crude Ccut in a vaporizer vessel. The vaporizer vessel is directly or indirectly in contact with a stripping column where liquid Ccuts are supplied to the upper region, direct gas and liquid exchange with the vaporizer vessel occurs in the lower region, and vaporous purified crude Ccuts are removed from the top region.

Process for providing a vaporous purified crude C4 cut as a feed steam for an extractive distillation with a selective solvent

Secondary streams in 1,3-butadiene processing plants still contain high amounts of valuable 1,3-butadiene. An energy-efficient process for purifying a recycle stream from a 1,3-butadiene processing plant is provided. The recycle stream is divided into two substreams: the first substream for prepurifying pure 1,3-butadiene feedstream by removing high boilers relative to 1,3-butadiene in a stripping column and the second substream in an extractive distillation plant.

Process for purifying a recycle stream from a 1,3-butadiene processing plant

A process is proposed for distillatively obtaining pure 1,3-butadiene from crude 1,3-butadiene in a plant comprising one or more distillation columns, comprising supply of a feed stream of crude 1,3-butadiene to the one distillation column or the first of the plurality of distillation columns, the one distillation column or the plurality of distillation columns having a flange with an internal diameter of &#x2267;80 mm, comprising two mutually opposite plane-parallel surfaces () with an intermediate seal () which seals the interior of the one distillation column or of the first of the plurality of distillation columns from an intermediate space () on the atmosphere side between the two mutually opposite plane-parallel surfaces (), and the intermediate space () on the atmosphere side between the two mutually opposite plane-parallel surfaces () being closed off from the atmosphere to form a chamber, wherein the chamber is purged continuously during the operation of the plant with a low-oxygen gas or a low-oxygen liquid comprising 1% by weight of molecular oxygen or less, based on the total weight of the low-oxygen gas or of the low-oxygen liquid.

Process for distillatively obtaining pure 1,3-butadiene from crude 1,3-butadiene

1,3-butadiene is obtained by extractive distillation with a selective solvent from a Ccut comprising Cacetylenes as secondary components in a dividing wall column having a bottom evaporator, in which a dividing wall is disposed in the longitudinal direction of the column to form a first subregion, a second subregion and a lower combined column region. The column is disposed upstream of an extractive wash column. The energy input into the dividing wall column via the bottom evaporator is controlled in such a way that a bottom stream containing solvent, Cacetylenes and 1,3-butadiene restricted such that the loss of 1,3-butadiene is economically acceptable, is drawn off and fed to an acetylenes outgasser where the Cacetylenes are stripped out overhead and purified solvent is obtained as the bottom stream.

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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), wherein the operation of the dividing wall column (TK) is set by regulation of the energy input into the dividing wall column (TK) via a bottom vaporizer (V) and setting of the number of the theoretical plates in the lower common column region (C) so that a bottom stream () consisting of purified solvent is obtained from the dividing wall column (TK), is proposed.

A process for fractionating a starting mixture of two or more components by extractive distillation using a selective solvent in a dividing wall column aligned in the longitudinal direction of the column and extending to the upper end of the column and dividing the column interior into a first region, a second region, and a lower combined column region. The starting mixture is fed into the first region, a first top stream is taken off from the first region, and a second top stream is taken off from the second region, each stream having a prescribed specification. The selective solvent is introduced in the upper part of the first region and/or in the upper part of the second region, and solvent flow into the first region and/or solvent flow into the second region are set so that each of the prescribed specifications for the top streams are met.

Method and device for extractive distillation

A process for fractionating a crude Cfraction comprising butanes, butenes, 1,3-butadiene and small amounts of other hydrocarbons including C-acetylenes, by extractive distillation using a selective solvent, wherein the crude Cfraction () is fed into the middle region of a first extractive distillation column (K I) and the selective solvent () is fed into the column at a point above that at which the crude Cfraction () is introduced and a gaseous side stream () which comprises the C-acetylenes together with predominantly the selective solvent and in which the concentration of the C-acetylenes is below the spontaneous decomposition limit is taken off from the first extractive distillation column (K I) at a point below the feed point for the crude Cfraction () and an overhead stream () comprising the components which are less soluble than the C-acetylenes in the selective solvent is taken off from the top of the first extractive distillation column, is proposed.

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).

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.

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Ellerstadt, Germany

Bernd Heida