Abstract: A process for the separation of dichlorobenzene mixtures containing m- and p-dichlorobenzene in which: (i) the mixture is as an extracting agent contacted with a phosphoric ester of the general formula (I) as an extracting agent in which R1, R2 and R3 are identical or different and represent an aliphatic or cycloaliphatic alkyl or alkenyl radical and R1, R2, and R3 together contain at least 3C-atom and not more than 12 C-atoms, or a mixture of different phosphoric esters (I) of formula or is contacted with a phosphine oxide of the general formula (II) as an extracting agent in which R1, R2 and R3 are identical or different and represent an aliphatic or cycloaliphatic alkyl or alkenyl radical or hydrogen, and R1, R2 and R3 together contain at least 3 C-atoms and not more than 12 C-atoms, or a mixture of different phosphine oxides of formula (II) or a mixture of said phosphoric esters of formula (I) and phosphine oxides of formula (II), and subsequently (ii) the components of the mixture are

Abstract: The invention relates to a method of avoiding corrosion in the separation of methylamine from a product stream (10) which is obtained in the preparation of methylamines by gas-phase reaction of methanol and ammonia and includes monomethylamine, dimethylamine, trimethylamine, ammonia and methanol as components, where ammonia is separated off by pure distillation in a first column (1), the remaining components of the product stream obtained as bottoms (12) are fed to a second column (2). Trimethylamine (14) is separated off in the second column (2) by extractive distillation with introduction of water. The further of the product stream obtained as bottoms (15) from the second column (2) are fed to a third column (3), in which monomethylamine and dimethylamine are separated off at the top. The monomethylamine and dimethylamine are separated by distillation in a fourth column (4). To avoid corrosion alkali metal hydroxide is added to the second or third column (3).

Abstract: Basic (meth)acrylates IV are prepared by transesterification of alkyl (meth)acrylates I in the presence of a catalyst and working-up of the reaction mixture by distillation, by a process in which a gas or gas mixture which is inert under the reaction conditions is passed through the reaction zone and/or heat exchanger.

Abstract: Bubble columns fractionate with vapor-liquid mass transfer efficiencies approaching that of distillation towers when vapor velocities in excess of 50% of jet flood are used. If the vapor velocities are pushed above about 70% of jet flood then the distillation performance of a given column packing becomes similar for both liquid continuous operation (bubble column mode) and vapor continuous operation (ordinary distillation tower mode).

Abstract: An apparatus for recycling the stripper solutions with higher recycling rate is disclosed. The apparatus includes a stripper condenser; a first buffer tank; a second buffer tank connecting to said stripper condenser by a first pipe and connecting to said first buffer tank by a second pipe; a recycling device connecting to said first buffer tank by a fourth pipe; a first pump mounted on said first pipe; a second pump mounted on said second pipe; a concentration detector mounted in said stripper condenser; and a controller electrically connected to said concentration detector, said flow meter, and said liquid level sensor for receiving the signals therefrom, and electrically connected to said first pump and said second pump for sending on-off messages to said second pump.

Abstract: A control apparatus and control method for controlling the separation in a dividing wall distillation column of at least two feeds into at least three products is disclosed. The apparatus uses a temperature measuring device to measure the temperature of fluid in the column, a controller, and a means for adjusting the temperature of fluid in the column. The temperature measuring device may be on either side of the dividing wall or above or below the dividing wall, and more than one such device may be used. The apparatus and method may be used in the production of alkylaromatic hydrocarbons by alkylating aromatic hydrocarbons with olefinic hydrocarbons.

Abstract: A dividing-wall column having a dividing wall which is essentially disposed along the long direction of the column is proposed, which divides the column interior into a feed part, a take off part, an upper shared column part and a lower shared column part, with feed in whole or in part in the vaporous state of a mixture to be separated between the upper region of the feed part and the lower region of the feed part and/or side stream take off in whole or in part in the vaporous state between the upper region of the take off part and the lower region of the take off part, where if feed is in whole or in part in the vaporous state the cross-sectional area of the upper region of the feed part is increased by plane-parallel displacement of the dividing wall toward the upper region of the take off part, and/or if the side stream take off is in whole or in part in the vaporous state, the cross-sectional area of the lower region of the take off part is increased by displacement of the dividing wall toward the lower r

Abstract: N-(2-hydroxyethyl)-2-pyrrolidone (HEP) is purified by a distillation sequence in which the purified HEP is recovered as a side stream without being separated as an overhead at any point in the procedure.

Abstract: This invention provides azeotrope-like compositions of 1,1,1,3,3-pentafluoropropane and water that are environmentally desirable for use as refrigerants, aerosol propellants, metered dose inhalers, blowing agents for polymer foam, heat transfer media, and gaseous dielectrics.

Abstract: A method for separating difluoromethane from a mixture of difluoromethane and at least one impurity, the method involving extractively distilling the mixture using dichloromethane as an extractive agent to recover a product stream of purified difluoromethane having a concentration of impurity lower than that of the mixture.

Abstract: A process is proposed for the separation of C5+ cuts by distillation into a low-boiler (A), a medium-boiler (B) and a high-boiler fraction (C) in one or more dividing-wall columns (TK), in which a dividing wall (T) is arranged in the longitudinal direction of the column with formation of an upper, common column region (1), a lower, common column region (6), a feed part (2, 4) with rectifying section (2) and stripping section (4), and a withdrawal part (3, 5) with rectifying section (5) and stripping section (3), with feed of the C5+ cut (A, B, C) into the central region of the feed part (2, 4), discharge of the high-boiler fraction (C) from the bottom of the column, discharge of the low-boiler fraction (A) via the top of the column, and discharge of the medium-boiler fraction (B) from the central region of the withdrawal part (3, 5), wherein the dividing ratio of the liquid reflux at the upper end of the dividing wall (T) is set in such a way that the proportion of high-boiling key components in the liquid re

Abstract: 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.

Abstract: An apparatus for recovering ethylene from a hydrocarbon feed stream, where the apparatus is a single distillation column pressure shell encasing an upper region and a lower region. The upper region houses an ethylene distributor rectifying section and the lower region houses a C2 distributor section and an ethylene distributor stripping section. Vapor passes from the lower region into the upper region, and liquid passes from the upper region to the lower region. The process for recovering the ethylene is also disclosed. The hydrocarbon feed stream is introduced into the C2 distributor section, and after a series of stripping and refluxing steps, distinct hydrocarbon products are recovered from the C2 distributor section, the ethylene distributor stripping section, and the ethylene distributor rectifying section, respectively.

Abstract: A process for the high yield production of high purity glacial methacrylic acid (“HPMAA”) with minimization of decomposition of hydroxy isobutyric acid (HIBA). The HPMAA is substantially pure, specifically 99% pure or greater with a water content of 0.05% or less. This improved process involves the steps of providing a crude MAA stream which was formed by hydrolyzing acetone cyanohydrin and, therefore, includes HIBA which is an intermediate product of the hydrolysis reaction, and purifying that crude methacrylic acid stream in a series of successive distillation steps.

Abstract: A process for preparing a salt-free aqueous hydroxylamine solution by reacting an aqueous solution of a hydroxylammonium salt with a base to give a mixture and separating from said mixture by distillation a salt-free aqueous hydroxylamine solution, involving using as a base an aqueous solution of a mixture of NaOH and KOH in a molar ratio Na+:K+ in the range from 70:30 to 95:5 and with a total concentration of Na+ and K+ in the range from 0.1 to 10 m/m % based on the total amount of the mixture.

Abstract: A dividing-wall column having a dividing wall which is essentially disposed along the long direction of the column is proposed, which divides the column interior into a feed part, a take off part, an upper shared column part and a lower shared column part, with feed in whole or in part in the vaporous state of a mixture to be separated between the upper region of the feed part and the lower region of the feed part and/or side stream take off in whole or in part in the vaporous state between the upper region of the take off part and the lower region of the take off part, where if feed is in whole or in part in the vaporous state the cross-sectional area of the upper region of the feed part is increased by plane-parallel displacement of the dividing wall toward the upper region of the take off part, and/or if the side stream take off is in whole or in part in the vaporous state, the cross-sectional area of the lower region of the take off part is increased by displacement of the dividing wall toward the lower r

Abstract: Crude ammonia is separated into a low boiler fraction, a high boiler fraction and an intermediate-boiling pure fraction by continuous fractional distillation in a distillation apparatus configured either as a dividing wall column or as a system of thermally coupled distillation columns. In the process of the present invention, the low boiler fraction is taken off at the top of the distillation apparatus. The intermediate-boiling pure fraction is obtained at a side offtake which is preferably provided with droplet precipitators. In addition, the gas loading of the distillation column is restricted so that the operating pressure is in the range from 2 to 30 bar and the F factor does not exceed 2.0 Pa0.5.

Abstract: An amine-containing mixture containing one or more amines, water, low-boilers and optionally high-boilers is fractionated by a process having the steps (iii) and (iv) and optionally the steps (i), (ii) and (v): (i) a (first) low-boiler fraction is separated off from the amine-containing mixture by distillation, (ii) a (first) high-boiler fraction is separated off from the amine-containing mixture by distillation, (iii) the amine-containing mixture is extracted with sodium hydroxide solution, producing an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-, (further) low-boiler- and possibly (further) high-boiler-containing second phase, (iv) the aqueous-organic second phase, is distilled, producing essentially anhydrous amine as bottom-phase take off or sidestream takeoff in the stripping part of the distillation column, an amine/water azeotrop as sidestream takeoff in the enrichment part of the column and a (further) low-boiler fraction as overhead takeoff, and recycling the amin

Abstract: The invention relates to a method for removing, by distillation, 6-aminocapronitrile from mixtures that contain 6-aminocapronitrile, adipodinitrile and hexamethylenediamine, by a) removing the hexamethylenediamine from the mixture while obtaining a mixture (I) that has a hexamethylenediamine content of less than 1 wt. -%, b) removing completely or partially the 6-aminocapronitrile from mixture (I) while obtaining a mixture (II) whose content in substances that have a higher boiling point as 6-aminocapronitrile under distillation conditions and that cannot be formed by dimerization reactions when 6-aminocapronitrile is thermally treated is less than 1 wt. -%, and c) completely or partially removing from mixture (II) the hexamethylenediamine that might be present while obtaining a mixture (IV) whose hexamethylenediamine content is higher than that of mixture (II), and a mixture (V) whose hexamethylenediamine content is lower than that of mixture (II).

Abstract: A process for preparing a salt-free aqueous hydroxylamine solution by distilling an aqueous solution of a hydroxylammonium salt and a base in a tray column having at least two mechanical trays, wherein random or structured packings are located above at least one tray of the tray column over the cross section of the column.

Abstract: A mixture containing one or more amines, water, low-boilers and high-boilers, is fractioned in a process wherein (i) low-boilers are separated from the mixture by distillation, (ii) high-boilers are separated from the mixture by distillation, (iii) the mixture is extracted with a sodium hydroxide solution to form an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-containing second phase, and (iv) the aqueous-organic second phase is distilled to form an amine/water azeotrop and an essentially anhydrous amine, and the amine/water azeotrop is recycled to the extraction step (iii).

Abstract: A process for the separation of diisobutylene from tertiary butyl alcohol utilizing pressure swing azeotropic distillation to achieve the desired separation. The pressure swing azeotropic distillation takes advantage of the fact that different azeotropes are formed at different pressures. Isobutylene in C4 streams is oligomerized in the presence of tertiary butyl alcohol to produce the diisobutylene. Tertiary butyl alcohol is present in the dimerization because it improves the selectivity to the dimer (diisobutylene) by suppressing further reaction to the trimer or higher. The diisobutylene is separated from the tertiary butyl alcohol utilizing two distillation columns. The first distillation is operated at a higher pressure than the second such that the minimum boiling azeotropes of tertiary butyl alcohol and diisobutylene have different concentrations of tertiary butyl alcohol. Diisobutylene is removed as bottoms from the first distillation column and unreacted C4's are removed as overheads at 60-130 psig.

Abstract: A process is described for the recovery of acrylonitrile from an ammoxidation reactor effluent stream containing acrylonitrile, water, and organic impurities. The process includes the steps of (a) quenching an ammoxidation reactor effluent stream that includes acrylonitrile, water, and organic impurities with an aqueous quench stream, thereby producing a cooled reactor effluent stream; (b) passing the cooled reactor effluent stream through an absorption column, thereby generating an absorber bottoms stream that includes water, acrylonitrile, and organic impurities; and (c) passing the absorber bottoms stream through a single recovery/stripper column, generating an acrylonitrile-rich overhead stream, a lean water side stream, and a recovery/stripper bottoms stream that includes organic impurities. The acrylonitrile-rich overhead stream can be passed through a decanter to separate water from acrylonitrile. The lean water side stream can be recycled for use in the absorption column.

Abstract: In a process for the continuous fractional distillation of mixtures comprising tetrahydrofuran, ?-butyrolactone and/or 1,4-butanediol to give at least three fractions, the fractionation is carried out in an assembly of distillation columns comprising at least one dividing wall column or at least one assembly of thermally coupled conventional distillation columns.

Abstract: In a process for purification of ethylene oxide by distillation an aqueous mixture comprising ethylene oxide, formaldehyde and at least 5% by weight of water is introduced via a feed into a distillation apparatus comprising at least one distillation column, the mixture being introduced at a height above the bottom of at least 8 theoretical stages, the ethylene oxide is taken off at the top and in the bottom phase a mixture is obtained which contains less than 5% by weight of ethylene oxide.

Abstract: A mixture containing mixture one or more amines, water, low-boilers and high-boilers, is fractioned in a process wherein (i) low-boilers are separated from the mixture by distillation, (ii) high-boilers are separated from the mixture by distillation, (iii) the mixture is extracted with a sodium hydroxide solution to form an aqueous, sodium-hydroxide-containing first phase and an aqueous-organic, amine-containing second phase, and (iv) the aqueous-organic second phase is distilled to form an amine/water azeotrope and an essentially anhydrous amine, and the amine/water azeotrope is recycled to the extraction step (iii).

Abstract: The present invention relates to a process for separating 2-butanol from tert-butanol/water by adding of tert-butanol such that the water concentration lowers to less than the limit concentration of the distillation boundary line connecting the two azeotropes TBA/water and SBA/water and is subsequently worked up by distillation.

Abstract: A process for separating secondary-butanol impurity from ethyl acetate (EtAc) by feeding the impure EtAc to a distillation column operating at a pressure of less than 1 bar absolute to provide (1) a stream comprising EtAc as a major component and (2) a residue or a second stream comprising at least some sec-butanol from said impure EtAc. The process can be applied to purifying EtAc derived from (a) catalytic reaction of ethylene with acetic acid followed by (b) a hydrogenation step. The 2-butanone impurity produced in step (a) is difficult to separate from EtAc, and step (b) converts it to sec-butanol which can be separated by the reduced pressure fractionation of the invention.

Abstract: There are disclosed an apparatus and a process for purification of an acrylic acid family.

Abstract: The present invention relates to a process for separating secondary butanol (also referred to as 2-butanol or SBA below) from tert-butanol/water mixtures which are obtained in the dissociation of tert-butanol (TBA), in particular tert-butanol prepared from industrial C4-hydrocarbon mixtures, into isobutene and water.

Abstract: A process for the enhanced recovery and operation of hydrogen cyanide (HCN)/heads column obtained from the reactor effluent of an ammoxidation reaction of propane, propylene or isobutylene by reducing the polymer formation above the feed tray in the heads tower.

Abstract: The invention relates to a method for separating and purifying an aqueous mixture that mainly consists of acetic acid, formic acid and high-boiling substances by extraction with a solvent in a cyclic process. The inventive method is characterized in that the flow of raffinate is fed to a solvent stripping column (11) with the major part of the water in order to remove the water from the cycle. The flow of extract is fed to a solvent recovery distillation column (8). In a first step, a mixture (A) that consists of water and solvent, is separated by overhead distillation. A mixture (B) that consists of acetic acid, formic acid and high-boiling substances is separated via a sump. Once the formic acid is removed in a column (29), mixture (B) is separated in an acetic acid distillation column to give pure acetic acid and high-boiling substances.

Abstract: Basic (meth)acrylates IV are prepared by transesterification of alkyl (meth)acrylates I in the presence of a catalyst and working-up of the reaction mixture by distillation, by a process in which a gas or gas mixture which is inert under the reaction conditions is passed through the reaction zone and/or heat exchanger.

Abstract: A method for the purification of crude acetonitrile comprising distilling the crude acetonitrile in a first fractional distillation column at below atmospheric pressure, withdrawing a first side draw fraction comprising acetonitrile, distilling the first side draw fraction in a second fractional distillation column at super atmospheric pressure, and withdrawing from the second distillation a second side draw fraction comprising purified acetonitrile.

Abstract: A process for preparing a salt-free aqueous hydroxylamine solution by reacting an aqueous solution of a hydroxylammonium salt with a base to give a mixture and separating from said mixture by distillation a salt-free aqueous hydroxylamine solution, comprises using as a base an aqueous solution of a mixture of NaOH and KOH in a molar ratio Na+:K+ in the range from 70:30 to 95:5 and with a total concentration of Na+ and K+ in the range from 0.1 to 10 m/m % based on the total amount of the mixture.

Abstract: A process for the separation of dichlorobenzene mixtures containing m- and p-dichlorobenzene by means of extractive rectification using an extracting agent is described.

Abstract: A perforated tray without downcomer in accordance with the present invention satisfies following conditions: (a) The hole has a diameter of 10 mm to 25 mm. (b) Two adjacent holes are spaced by a distance of 1.2 d to 3 d, measured between the two centers. (c) The tray thickness is 2 mm to 8 mm. (d) The opening ratio is 10% to 30%. A perforated tray tower without downcomer fitted with two or more such perforated trays without downcomer in accordance with the present invention satisfies following conditions: (g) Perforated trays are spaced by a distance of 0.1 D to 0.5 D (D denotes the tower diameter). (h) The levelness of each perforated tray is 8 mm or less. (i) If a plurality of perforated trays are used at the same stage, the two most closely located holes that respectively belong to adjacent perforated trays are spaced by a distance of 50 mm to 150 mm, measured between the two centers.

Abstract: A process for producing high purity isopropyl alcohol. In one embodiment, the process includes the steps of: (a) feeding a feed stream comprising at least about 99.9 wt. % isopropyl alcohol into a separation column; (b) separating the isopropyl alcohol into an overhead stream taken overhead from the separation column and a bottoms stream taken as bottoms from the separation column; and (c) removing the high purity isopropyl alcohol at a point: (i) below where the feed stream enters the separation column but above the bottoms stream, or (ii) above where the feed stream enters the separation column but below the overhead stream. The high purity isopropyl alcohol has a metals content of less than about 1 ppb and a water content of less than about 100 ppm.

Abstract: A method for obtaining high purity N-(2-hydroxyethyl)-2-pyrrolidone satisfactory for use as an intermediate material for N-vinyl-2-pyrrolidone from a reaction liquid formed of a reaction between y-butyrolactone and 2-aminoethanol, i.e., a liquid containing N-(2-hydroxyethyl)-2-pyrrolidone, compounds having boiling points lower than that of N-(2-hydroxyethyl)-2-pyrrolidone and compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone. The method is characterized by distilling said reaction liquid using a distillation column, whereby obtaining a liquid containing the compounds having the lower boiling points than that of N-(2-hydroxyethyl)-2-pyrrolidone and N-(2-hydroxyethyl)-2-pyrrolidone as a distillate liquid from the column top and a liquid containing compounds having boiling points higher than that of N-(2-hydroxyethyl)-2-pyrrolidone as a bottom liquid.

Abstract: The present invention provides a continuous process for recovering acetone from a waste stream from an acetone purification stage, whereas said waste stream comprises mesityl oxide and optionally acetone by separating the waste stream in a separating device at least in one stream comprising mesityl oxide and optionally a further stream comprising acetone, by than concentrating mesityl oxide in the mesityl oxide containing stream and finally by recycling the concentrated mesityl oxide stream to the separating device and bringing it into contact with a basic or acidic aqueous medium or with an acidic catalyst in the presence of water whereby mesityl oxide is at least partially hydrolyzed to acetone.

Abstract: The invention relates to a method for the production of phthalic anhydride to a specification, using a distillative purification of crude phthalic anhydride, by introduction of crude phthalic anhydride into a distillation column, operating at reduced pressure, withdrawal of the low-boiling fraction from the head, or near the head of the column and withdrawal of the phthalic anhydride, which meets the specification, from a side-tap on the column, whilst operating the column at a reflux ratio x, with 1:1.7<x<1:3.

Abstract: Process for carrying out a reactive distillation in the presence of a heterogeneous catalyst which is suspended as disperse phase in the liquid, wherein part of the catalyst-containing suspension is continuously discharged from the column and is treated in a work-up stage and at least part of the work-up catalyst is returned to the column.

Abstract: A method for refining an easily polymerizable matter while preventing an easily polymerizable matter-containing substance from being polymerized and an apparatus for use in the method are disclosed. The method and apparatus for refining and separating the easily polymerizable matter-containing substance by the use of a distillation column provided with a heat exchanger set the linear velocity of a vapor in a connecting line intervening between the distillation column and the heat exchanger at a level of not less than 5 m per second and the retention time of the vapor at a level of not more than 3 seconds.

Abstract: 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.

Abstract: A process for working up by distillation the crude products obtained in the process according to DE-A 196 07 954 and containing 1,6-hexanediol (HDO), 1,5-pentanediol (PDO) or caprolactone (CLO) in order to obtain the corresponding pure products, the working-up by distillation being carried out in each case in a dividing wall column (TK) in which a dividing wall (T) is arranged in the longitudinal direction of the column with formation of an upper common column region (1), a lower common column region (6), a feed section (2, 4) having a rectification section (2) and stripping section (4), and a take-off section (3, 5) having a stripping section (3) and rectification section (5), with feeding of the respective crude product HDO, PLO or CLO in the middle region of the feed section (2, 4) and removal of the high boiler fraction (C) from the bottom of the column, of the low boiler fraction (A) via the top of the column and of the medium boiler fraction (B) from the middle region of the take-off section (3, 5), or

Abstract: A method for the separation and purification of an aqueous mixture of main components, namely acetic acid and formic acid and non-volatiles by extraction, uses a solvent in a circulatory system. A raffinate stream is mixed with the larger proportion of water from a solvent stripper column (11) for the removal of water. The extraction stream is introduced into a solvent distillation column (8), from which in a first step involving the use of a mixture (A) containing a larger proportion of the solvent is separated out via a header and a mixture (B) of formic acid, water and solvent is separated out via a side offtake and a mixture (C) of acetic acid and non-volatiles is also separated out. A mixture (B) is introduced into a formic acid distillation column (4) for further processing, and a mixture (C) is introduced into an acetic acid distillation column (5), and purified acetic acid is subsequently isolated in the acetic acid distillation column (5) from the header.

Abstract: An object of the present invention is to provide a method for simulating a distillation apparatus having a coupling-type distillation column (10), the method speeding completion of simulation operation. The simulation for the distillation apparatus including a coupling-type distillation column (10) is performed by use of a simulation program for simulating a distillation apparatus including a main column (31) and a side column (32) in combination.

Abstract: This invention relates to a continuous process and an apparatus (1) for removing dissolved and undissolved solids and/or high boiling point liquid contaminants from a mixture of miscible liquids (9). A recycle liquor stream (6) is fed at high velocity through a heat exchanger having a single flow path (12) and the heat added by the heat exchanger is sufficient to vaporize the feed stream (2) when the recycle liquor and feed stream are mixed upon delivery to the separation vessel (3).

Abstract: A modular apparatus for fractional distillation and other forms of vapor-liquid contacting is presented. The apparatus performs cocurrent contacting of vapor and liquid in a number of identical structural units which are placed in horizontal layers in a column or other enclosure. The structural units, or modules, are horizontally spaced apart in each layer to provide spaces for the downcomers from the modules of the next higher layer. The downcomers deliver the liquid to one of two inclined contacting channels, with the contacting channels discharging the vapor and liquid into separation chambers at the top of the module. Vapor flows upward from the separation chambers to the contacting channel of the next higher module and liquid flows down through a single central downcomer to the next lower contacting channel.

Abstract: Bubble columns fractionate with vapor-liquid mass transfer efficiencies approaching that of distillation towers when vapor velocities in excess of 50% of jet flood are used. If the vapor velocities are pushed above about 70% of jet flood then the distillation performance of a given column packing becomes similar for both liquid continuous operation (bubble column mode) and vapor continuous operation (ordinary distillation tower mode).