Methods and systems for recovering naphtha blend stock from hydrocarbons produced in a fluid catalytic cracking (FCC) process. In particular, the disclosure concerns gas plants for an FCC process, wherein the gas plant uses a dividing wall column. The dividing wall column essentially performs the functions that are performed in a traditional FCC gas plant by three different columns, namely, a primary absorber, a stripper, and a debutanizer.

There is provided a method of producing ethylene oxide and ethylene glycol capable of reducing a concentration in discharged water of 1,4-dioxane contained generated in a step of producing ethylene oxide and ethylene glycol.

A method of producing ethylene oxide and ethylene glycol includes a predetermined step of producing ethylene oxide, and a step of extracting a part of a column bottom liquid of an ethylene oxide stripping column in the step of producing ethylene oxide and supplying the extracted column bottom liquid to a by-produced ethylene glycol concentration column, concentrating ethylene glycol produced as a by-product in the step of producing ethylene oxide, and distilling and separating 1,4-dioxane produced as a by-product in the step of producing ethylene oxide, wherein the by-produced ethylene glycol concentration column is a divided wall distillation column.

The invention relates to the production of (meth)acrylic esters according to a continuous process by transesterification, and in particular to the purification of a crude reaction mixture comprising a C.sub.4-C.sub.12 (meth)acrylic ester using a divided wall column employed in a particular configuration. This configuration results in a simplification of the purification process with a reduced energy consumption and a minimized content of impurities present in the purified (meth)acrylic ester. The invention also relates to a process for the production of C.sub.4-C.sub.12 (meth)acrylic ester comprising this recovery/purification process.

A two-step hydrocracking process with a distillation step wherein a dividing wall distillation column is used, the dividing wall dividing the lower part of the column into two compartments, located in the section of the column located under the supply of said column with the unconverted effluent resulting from the first hydrocracking step. The distillation column is fed on either side of the vertical dividing wall with the liquid hydrocarbon effluent from the first hydrocracking step and with the liquid hydrocarbon effluent from the second hydrocracking step, allowing the concentration of the HPNAs contained in the effluent from the second hydrocracking step in a specific compartment of the column delimited by the dividing wall and avoiding the dilution of said HPNAs by the unconverted effluent from the first hydrocracking step. The present invention allows purging of purer HPNAs.

The invention relates to a method (100, 200) of obtaining one or more olefins, in which, using an oxidative coupling of methane (10), a gas mixture comprising hydrogen, methane, carbon monoxide and higher-boiling hydrocarbons than methane is formed and is subjected to a low-temperature separation (1-5), characterized in that the low-temperature separation (1-5) is conducted using a rectification column (2) having a first separation region (21), a second separation region (22) arranged above the first separation region (21), and a condenser-evaporator (23), wherein the gas mixture is cooled, fed at least partly as first separation feed into the first separation region (21) and subjected to a first rectification in the first separation region (21) to form a first tops gas and a first bottoms liquid, wherein, using a first proportion of the first tops gas in the condenser-evaporator (23), a condensate which is recycled to the first separation region and, using a second proportion of the tops gas, a second separation feed which is fed into the second separation region (22) are formed, and wherein the second separation feed is subjected to a second rectification in the second separation region to form a second tops gas and a second bottoms liquid.

The present disclosure provides a method and an apparatus for efficiently recovering an amide-based compound such as N-methyl-2-pyrrolidone from an aqueous solution containing an amide-based compound such as N-methyl-2-pyrrolidone.

Process for isolating pure 1,3-butadiene from a crude C.sub.4 fraction by extractive distillation using a selective solvent, wherein (a) the crude C.sub.4 fraction is introduced into a predistillation column, a first low boiler fraction comprising C.sub.3-hydrocarbons is taken off as overhead stream, a gaseous C.sub.4 fraction is taken off as side stream and a first high boiler fraction is taken off as bottom stream, (b) the gaseous C.sub.4 fraction 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.

Disclosed is a vapor splitter including: a chimney tray dividing an internal space of a housing into an upper space and a lower space; a chimney provided on the chimney tray to enable the upper space and the lower space to communicate with each other; a cap covering the chimney with a gap therebetween such that a gas discharge hole is formed so that gas, coming out through the chimney, can be transferred to the upper space through the gas discharge hole; a liquid feeding unit for feeding liquid to the upper space; and a liquid discharging unit for discharging the liquid out of the upper space. The size of the gas discharge hole is adjusted by controlling the height of the liquid collected on the chimney. Further disclosed is a method of adjusting a vapor split ratio using the vapor splitter.

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.