A mass transfer column comprising: a shell (12); an open internal region (14) defined by said shell; and a mass transfer assembly (16) positioned in the open internal region (14), the mass transfer assembly (16) comprising: a dividing wall (18) forming first and second sub-regions; one or more zones of mass transfer structures positioned in the first and second sub-regions (22 and 24); and a liquid flow divider (48) positioned above the dividing wall (18) for delivering a volumetric split of liquid to the first and second sub-regions. The liquid flow divider (48) may comprise a moveable weir (68) or a valve (180) in order the change the ratio of liquid flow between the two sub-regions.

A mass transfer assembly has at least one dividing wall, zones of mass transfer structures on opposite sides of the dividing wall, and a vapor flow restrictor that is operable to vary the split of vapor ascending through the zones of mass transfer structures on the opposite sides of the dividing wall.

In a process and system for treatment of feed stocks comprising alkylating agent and metal salts, the metal salts are removed from the feedstock by an efficient combination of separations processes. The processes may take place in one or more stages, each stage taking place in one or more vessels. Such treatment processes may remove 99.9% or more of metal salts from a feedstock, while recovering 99.9% or more of the alkylating agent from the feedstock for use in an alkylation reaction, especially of aromatics such as toluene and benzene. Preferred alkylating agents include methanol and mixtures of carbon monoxide and hydrogen, for methylation of toluene and/or benzene. The methylation proceeds over an aluminosilicate catalyst and preferably yields para-xylene with 75% or greater selectivity.

Separation of chlorosilane mixtures containing boron, arsenic, and/or phosphorus impurities is facilitated by a distillative separation using at least one divided column, with recycle streams to a first column being passed through an external absorbent for the impurities.

This present disclosure relates to processes and apparatuses for use of a single dividing wall distillation column for phenol fractionation. More specifically, the present disclosure relates to processes and apparatuses for phenol fractionation by combining crude acetone column and cumene-AMS column into a single dividing wall distillation column. The proper allocation of steam or water injection, chemical treatment reactor and internal liquid phase separator, the positioning of the side draw enables high yield of acetone and phenol.

The xylene isomerization process unit and the transalkylation process units are combined in the present invention. A fractionation column can be shared by the two units, reducing the capital cost of the complex. In some embodiments, a split shell fractionation column and a split separator can be used.

Embodiments disclosed relate to a debutanizer with a dividing wall. The configuration of the debutanizer includes having a feed section, a top section, a bottom section, and a draw-off section. The debutanizer produces a C4s product, a C5s product and a natural gasoline (NG) product from a C4+s feed. The dividing wall is configured such that an upper portion of the dividing wall is positioned off-set from a vertical centerline and a lower portion of the dividing wall is positioned along the vertical centerline of the debutanizer. A process of use of the debutanizer is also disclosed. A natural gas liquids (NGL) system that includes parallel debutanizers, each with a dividing wall, and a process of use of such system, is also disclosed.

Disclosed is a divided wall column, comprising: a column shell; a divided wall provided vertically inside the column shell, defining a divided wall section between an upper edge and a lower edge of the divided wall; and a liquid distributor provided within the divided wall section, characterized in that, the liquid distributor is fixed only to the column shell but not to the divided wall. By using the divided wall column of the present invention, a defect involved in conventional divided wall columns, i.e. a maldistribution of fluid over mass transfer elements caused by a manufacturing defect of the divided wall resulted from its manufacturing process and/or a deformation thereof under operation conditions, can be minimized or even avoided.

The invention relates to a process for continuously preparing di-C.sub.1-3-alkyl succinates by reacting succinic acid with an C.sub.1-3-alkanol in the presence of a fixed-bed heterogeneous acidic esterification catalyst in a tubular reactor at a temperature in the range of from 60 to 100° C., wherein a mixture, comprising succinic acid, C.sub.1-3-alkanol, mono-C.sub.1-3-alkyl succinate, di-C.sub.1-3-alkyl succinate and water, is formed in a mixing stage and fed to the entrance of the tubular reactor, and wherein 5 to 75% of the outlet flow rate of the tubular reactor are recycled directly to the mixing stage as a recycle stream, and the molar ratio of C.sub.1-3-alkanol to succinic acid added to the mixing zone, and not including the C.sub.1-3-alkanol and succinic acid at the recycle stream, being in the range of from 2.0 to 9.5. The invention furthermore relates to a process for separating the reactor effluent of an esterification of succinic acid with an C.sub.1-3-alkanol to give di-C.sub.1-3-alkyl succinates by distillation, wherein the separation is performed in a divided wall column in which C.sub.1-3-alkanol and water are removed in a top draw of the column, di-C.sub.1-3-alkyl succinate is removed in a side draw of the column, and wherein mono-C.sub.1-3-alkyl succinate and succinic acid are removed in a bottom draw of the column.

A process and system for the production of at least one xylene isomer is provided. The process includes passing a first stream to one side of a split shell fractionation column and a second stream to the other side of the column. The first stream has a higher ratio of methyl to C2+ alkyl-substituted C9 aromatic compounds than the second stream. A bottoms stream from the one side is separated and passed as feed to a transalkylation zone.