Abstract: Process for the continuous fractional distillation of mixtures including morpholine (MO), monoaminodiglycol (ADG), ammonia and water obtained by reaction of diethylene glycol (DEG) with ammonia, which includes separating off ammonia at the top of a first distillation column K10, feeding the bottoms from K10 to a second distillation column K20 in which water and organic products are separated off at the top at a temperature at the top in the range from 45 to 198° C. and a pressure in the range from 0.1 to 15 bar, feeding the bottoms from K20 to a third distillation column K30 in which MO and organic products having a boiling point of <140° C. (1.013 bar) are separated off at the top or at a side offtake and ADG and organic products having a boiling point of >190° C. (1.013 bar) are separated off at the bottom, feeding the MO including stream which is separated off at the top or at a side offtake of the column K30 to a fourth column K40 in which organic products having a boiling point of ?128° C. (1.

Abstract: A process for reducing the energy consumption of a distillation column is disclosed. The process includes drawing off an intermediate vapor stream from the rectification section of the distillation column. The vapor stream is compressed and the heat in the vapor stream is exchanged with a portion of the liquid bottoms stream. The heat transfer condenses a portion of the vapor stream, while vaporizing the liquid bottoms stream.

Abstract: The system contains a liquid-tight enclosure. An input source is connected to the liquid-tight enclosure for inputting water into the liquid-tight enclosure. A heating element is in thermal communication with at least a portion of the water within the liquid-tight enclosure. A plurality of substantially vertical plates are aligned along a substantially horizontal axis within the liquid-tight enclosure. Each of the substantially vertical plates has an opening. A groove is formed along each of the substantially vertical plates. A first end of the groove on each of the substantially vertical plates is proximate to the opening. At least one manifold extends through a plurality of the openings of the substantially vertical plates. The manifold is in fluid communication with a plurality of the first ends of the grooves. An output opening is formed in the liquid-tight enclosure. The output opening is arranged in fluid communication with the manifold.

Abstract: An energy-efficient extractive distillation process for producing anhydrous ethanol from aqueous/ethanol feeds containing any range of ethanol employs an extractive distillation column (EDC) that operates under no or greatly reduced liquid reflux conditions. The EDC can be incorporated into an integrated process for producing anhydrous ethanol used for gasoline blending from fermentation broth. By using a high-boiling extractive distillation solvent, no solvent, is entrained by the vapor phase to the EDC overhead stream, even under no liquid reflux conditions. The energy requirement and severity of the EDC can be further improved by limiting ethanol recovery in the EDC. In this partial ethanol recovery design, ethanol which remains in the aqueous stream from the EDC is recovered in a post-distillation column or the aqueous stream is recycled to a front-end pre-distillation column where the ethanol is readily recovered since the VLE curve for ethanol/water is extremely favorable for distillation.

Abstract: A method for the separation of hydrocarbon compounds utilizing a dividing wall distillation column is described. The dividing wall distillation column enables one or more side draw stream to be removed from the dividing wall distillation column in addition to an overhead stream and a bottoms stream.

Abstract: A feed gas conditioner.

Abstract: Processes and apparatuses for separating diisopropylbenzene (DIPB) and triisopropylbenzene (TIPB) from a feed including DIPB, TIPB, and polyalkylate heavies are disclosed. The disclosed processes include introducing the feed into a distillation column having a column top pressure of less than 5 psia, a column bottoms pressure of less than 3 psi, and preferably 2 psi or less above the column top pressure with a bottoms temperature ranging from about 435° F. to about 465° F. The processes also include taking off a side draw including at least 99.8 wt % of the DIPB and at least 50 wt % of the TIPB present in the feed and a bottoms stream including at least 95 wt % of the heavies contained in the distillation feed. The low temperature bottoms temperature enables high pressure steam to be used as the bottoms reboiler heat source.

Abstract: Aromatic amines are produced by catalytic hydrogenation of aromatic nitro compounds. The reaction mixture generated by this hydrogenation is then worked up by distillation in a manner which makes it possible to substantially free the amine of water with increased energy efficiency. Water free of amine and low boilers and the low boiling materials are also obtained.

Abstract: This invention relates to methods of removing impurities from compounds having similar volatilities to form ultra high purity compounds.

Abstract: A dividing wall column is described which includes the following segments: a) an upper column region (1), b) an enrichment section (2) of the feed section, c) a stripping section (4) of the feed section, d) an upper part (3) of the offtake section, e) a lower part (5) of the offtake section, f) an intermediate region (9) of the feed section, g) an intermediate region (10) of the offtake section and h) a lower column region (6). The dividing wall column has a dividing wall (7) is located vertically between the segments b) (2) and d) (3) and between the segments c) (4) and e) (5). The segments b) (2), d) (3), c) (4) and e) (5) have separation-active internals, Segment b (2) has a cross-sectional area Ab which is at least 10% smaller than the cross-sectional area Ad of segment d) (3), and segment c) has a cross-sectional area Ac which is at least 10% greater than the cross-sectional area Ae of segment e) (5).

Abstract: The present invention relates to a process for purifying monomers, by evaporating at least a portion of the monomers present in a starting composition and then condensing it, which is characterized in that at least a portion of the starting composition is evaporated in a short-path evaporator, the mass flow density of the vapours {dot over (m)} being selected according to the relation (I) m . ? 1800 ? kg · K mbar · m 2 · h · kg kmol · p i · ( M ~ T ) 0.5 ( I ) in which {tilde over (M)} is the average molar mass of the vapours in the short-path evaporator in kg/kmol T is the temperature of the vapours in K pi is the pressure in the short-path evaporator in mbar {dot over (m)} is the mass flow density of the vapours in kg/(m2·h). A further aspect of the present invention is a plant for performing the process.

Abstract: The present invention relates to a process for distilling an aqueous polymethylol mixture which comprises a polymethylol of the formula (I) (HOCH2)2—C—R2??(I) in which each R is independently a further methylol group or an alkyl group having 1 to 22 carbon atoms or an aryl or aralkyl group having 6 to 22 carbon atoms, a tertiary amine, water and the adduct of tertiary amine and formic acid (amine formate), which comprises performing the distillation in a distillation column which is connected at the bottom to an evaporator, the bottom temperature being above the evaporation temperature of the monoester of formic acid and polymethylol (polymethylol formate) which forms during distillation. The present invention further relates to a composition comprising polymethylol and 1 to 10 000 ppm by weight of polymethylol formate, and to the use thereof.

Abstract: Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

Abstract: The present case relates to a process for the purification of lactide from a crude lactide vapor product stream which process comprises a rectification/condensation step leading to a lactide-enriched condensate.

Abstract: An energy-efficient extractive distillation process for producing anhydrous ethanol from aqueous/ethanol feeds containing any range of ethanol employs an extractive distillation column (EDC) that operates under no or greatly reduced liquid reflux conditions. The EDC can be incorporated into an integrated process for producing anhydrous ethanol used for gasoline blending from fermentation broth. By using a high-boiling extractive distillation solvent, no solvent is entrained by the vapor phase to the EDC overhead stream, even under no liquid reflux conditions. The energy requirement and severity of the EDC can be further improved by limiting ethanol recovery in the EDC. In this partial ethanol recovery design, ethanol which remains in the aqueous stream from the EDC is recovered in a post-distillation column or the aqueous stream is recycled to a front-end pre-distillation column where the ethanol is readily recovered since the VLE curve for ethanol/water is extremely favorable for distillation.

Abstract: Procedure of refining crude olive pomace oil obtained through centrifuging or decantation of the pomace, comprising the stage of filtration of the starting crude olive pomace oil carried out through filters having a pore size comprised in the interval from 0.1 to 20 microns and at a temperature below 70° C., preferentially between 35 and 45° C.

Abstract: A splitter system is disclosed that produces a product stream from a mixed stream of two materials with similar boiling points. A multi-stage heat pump compressor is used in combination with a bottoms reboiler and an intermediate reboiler resulting in reduced utility consumption. The appropriately placed intermediate reboiler enables use of a lower temperature heat source relative to the bottoms reboiler heat source. As a result, a lower pressure overhead vapor stream can be used to deliver heat to both the intermediate and bottoms reboilers, thereby conserving energy. The first stage of the multi-stage heat pump compressor delivers pressurized overhead vapor to the intermediate reboiler and the second stage provides pressurized overhead vapor to the bottoms reboiler. The disclosed design and method lessens the heat pump compressor power consumption and trim condenser duty for a propylene/propane splitter system by over 20%.

Abstract: The apparatus includes at least two adsorptive separation zones to separate para-xylene from a feed stream comprising C8 aromatic hydrocarbons and at least one C9 aromatic hydrocarbon component. The first adsorptive separation zone delivers a raffinate stream to a raffinate distillation zone and an extract stream to an extract distillation zone. The raffinate distillation zone delivers a stream to the second adsorptive separation zone and at least one of the extract distillation zone and raffinate distillation zone delivers a recycle stream to the first adsorptive separation zone.

Abstract: A dividing wall column comprises the following segments: a) an upper column region (1), b) an enrichment section (2) of the feed section, c) a stripping section (4) of the feed section, d) an upper part (3) of the offtake section, e) a lower part (5) of the offtake section, f) an intermediate region (9) of the feed section, g) an intermediate region (10) of the offtake section and h) a lower column region (6). For the purposes of the present invention, it is essential that the dividing wall (7) is located vertically between the segments b) (2) and d) (3) and between the segments c) (4) and e) (5), the segments b) (2), d) (3), c) (4) and e) (5) have separation-active internals and the cross-sectional area Ab of the segment b) (2) is at least 10% smaller than the cross-sectional area Ad of segment d) (3), and the cross-sectional area Ac of the segment c) (4) is at least 10% greater than the cross-sectional area Ae of segment e) (5).

Abstract: A method for the separation of hydrocarbon compounds utilizing a dividing wall distillation column is described. The dividing wall distillation column enables one or more side draw stream to be removed from the dividing wall distillation column in addition to an overhead stream and a bottoms stream.

Abstract: The invention relates to a method for yielding boron-depleted chlorosilanes from a chlorosilane mixture containing boron by means of separation by distillation of a boron-enriched distillation flow. The invention further relate to a device for yielding boron-depleted chlorosilanes from a chlorosilane mixture containing boron.

Abstract: One embodiment of a method of water treatment comprising straining fractionated water to remove particles larger than one micron in diameter, decanting the strained fractionated water to remove surfactants and oil, evaporating the decanted water to provide concentrated brine and water vapor, and condensing the water vapor.

Abstract: A microfluidic dynamic vapor control system adapted to change the chemistry of small drops by dynamically controlling the vapor content surrounding the drops. The small volume surface area ratio makes this an efficient mechanism for controlling chemistry in nanovolumes. The system uses small reservoirs of material that can produce vapor on demand, and microfluidic channels that direct the vapor into a small chamber that holds a drop of the solution of interest. By changing the vapors that enter the chamber, the chemical composition of the drop can be modified.

Abstract: The present invention relates to a process for improving the color stability by postpurifying piperazine, the steps comprising preparing an aqueous piperazine solution by introducing solid or liquid piperazine having a degree of purity of at least 90% by weight in water; removing the water by distillation; isolating the piperazine with a predefined maximum residual content of water. The invention further provides a rapid test of aging for checking the improvement in the color stability.

Abstract: A process for the polymerisation of olefins is disclosed wherein at least part of a stream, preferably a catalytically active stream, withdrawn from a polymerisation reactor is passed through a fractionator so as to remove hydrogen and active fines.

Abstract: The present invention generally relates to the small-scale separation of a mixture of two or more components with different boiling points into enriched fractions. In some embodiments, a first and second fluid (e.g., a liquid and a gas, a liquid and a liquid, etc.) are passed through a channel. The first fluid may comprise at least two components, each with a unique boiling point. Upon contacting the first and second fluids within the channel, at least a portion of the most volatile of the components in the first fluid (i.e., the component with the lowest boiling point) may be transferred from the first fluid to the second fluid. In some instances, the transfer of the volatile component(s) from the first fluid to the second fluid may be expedited by heating, in some cases above the boiling point(s) of the component(s) to be transferred from the first fluid to the second fluid. Contact between the first and second fluids may be maintained, for example, via segmented flow, bubbling flow, etc.

Abstract: A method is provided for recovering a catalytic element from a fuel cell membrane electrode assembly. The method includes grinding the membrane electrode assembly into a powder, extracting the catalytic element by forming a slurry comprising the powder and an acid leachate adapted to dissolve the catalytic element into a soluble salt, and separating the slurry into a depleted powder and a supernatant containing the catalytic element salt. The depleted powder is washed to remove any catalytic element salt retained within pores in the depleted powder and the catalytic element is purified from the salt.

Abstract: A differential vapor pressure (DYP) cell is disposed in a divided wall column that receives a feed comprising a first, second, and third component. A separation section on the feed side of the divided wall column separates the feed in a vapor comprising the first and second component, and a liquid comprising the second and third component. The DYP cell is disposed in the divided wall column at a level below the point where the feed enters the column, and the DYP cell measures the concentration of the first component.

Abstract: Process for distillatively separating a mixture containing a vinyl ether of the general formula (I) R1—O—CH?CH2??(I) and alcohol of the general formula (II) R2—OH??(II) in which R1 and R2 are each independently a saturated or unsaturated, aliphatic or cycloaliphatic radical having from 2 to 10 carbon atoms, and in which the alcohol (II) has a boiling point which is at least 1° C. higher, measured at or extrapolated to 0.1 MPa abs, than the vinyl ether (I), by a) passing the mixture into a first distillation column and withdrawing, as a top product, an azeotrope containing vinyl ether (I) and alcohol (II) and, as a bottom product, a stream enriched with the alcohol (II); b) passing the azeotrope containing vinyl ether (I) and alcohol (II) from the first distillation column into a second distillation column which is operated at a pressure which is from 0.

Abstract: Processes and systems for purifying ethylene oxide, including introducing a feed stream including ethylene oxide to a heat exchanger to heat the feed stream, feeding the heated feed stream to a distillation apparatus base below a first stage, removing from the distillation apparatus an impurity fraction as a top exit stream from the distillation apparatus located at a top take-off on the distillation apparatus, removing from the distillation apparatus an ethylene oxide stream of 99.7 weight percent purity, based on the total weight of the ethylene oxide stream, from the distillation apparatus, and removing from the distillation apparatus an aldehyde enriched fraction as a bottom stream from the distillation apparatus, where the aldehyde enriched fraction is fed directly to a glycol reactor.

Abstract: The process employs at least two distillation zones located within a column shell to produce an overhead and bottoms product from the first distillation zone and an intermediate product from the second distillation zone. Fluid is withdrawn from a side draw stage in the first distillation zone and passed through a conduit to the second distillation zone. A partition envelopes the second distillation zone to prevent mass transfer with the first distillation zone proximate the partition. The second distillation zone may be located relative to the first distillation zone to benefit from heat transfer across the partition.

Abstract: A process for recovering crude 1,3-butadiene from a C4 fraction 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 (17) consisting of purified solvent is obtained from the dividing wall column (TK), is proposed.

Abstract: A process of separating a purified propylene oxide from a crude epoxidation product produced, preferably, in an epoxidation reaction of propylene with hydrogen peroxide. The process involves removing bulk water, bulk methanol, and unreacted propylene from the crude epoxidation product and thereafter subjecting the resulting propylene oxide product to extractive distillation with water as an extraction solvent. Under distillation conditions, including a bottoms temperature of greater than about 55° C. and less than about 75° C., an overhead or side-cut distillate stream containing a purified propylene oxide is obtained with low yield loss of propylene oxide to propylene glycols and other glycol heavies. The purified propylene oxide can be further purified in a finishing distillation to obtain propylene oxide meeting commercial grade purity requirements.

Abstract: The invention relates to an energy efficient process for the distillative working-up of aqueous amine solutions that occur in the catalytic hydrogenation of nitroaromatic compounds. In this process, the amine is freed from water and also the water is obtained free from amine and low-boiling compounds and the concentrated low-boiling compounds are obtained.

Abstract: 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.

Abstract: The invention relates to a continuously operated process for the purification by distillation of the oxirane formed in the oxirane synthesis by reaction of a hydroperoxide with an organic compound, wherein the crude oxirane is separated in a dividing wall column into low-, intermediate- and high-boiling fractions and the oxirane is taken off as intermediate boiler at the side offtake in a concentration of at least 99.9%.

Abstract: The invention relates to a process for distillatively purifying crude dimethylacetamide (crude DMAc) comprising DMAc, low boilers and high boilers 5 by removing the low boilers and the high boilers to obtain pure DMAc in one of the column configurations listed hereinbelow: (I) a main column (MC) with sidestream column (SC) or (II) a dividing wall column (DWC), which operating at least the main column (MC) in column configuration (I) and the dividing wall column (DWC) in column configuration (II) at a top pressure in the range from 0.5 to 1.8 bar absolute.

Abstract: A device for recovering drinking water from condensate includes a self-supporting moulded part 11 formed of a transparent synthetic resin such as PET or PC, which is resistant to UV radiation. The moulded part 11 presents an open bottom area 16 with a collecting channel 15 on the edge side, with the collecting channel 15 presenting an inner wall 18 oriented towards the circumferential surface 12 and serving, at the same time, as floating aid, and with the moulded part 11 being provided with a pouring opening in its upper section 13 . For the manufacture of this device, a vacuum is created in a special deep-drawing tool not only in the region of the circumferential surface to be produced but also in the region of the collecting channel to be formed, and the moulded part is separated from a separated deep-drawing tool element outside the zone of the collecting channel.

Abstract: Process for the continuously operated purification by distillation of the methanol used as solvent in the synthesis of propylene oxide by reaction of a hydroperoxide with propylene, with the methoxypropanols being separated off simultaneously, wherein the solvent mixture obtained in the synthesis is separated in a dividing wall column into a low-boiling fraction including methanol, an intermediate-boiling fraction containing the methoxypropanols as azeotrope with water and a high-boiling fraction including water and propylene glycol.

Abstract: The present invention relates to a process for the manufacture and separation of dinitrile compounds. It relates more particularly to a process for the manufacture and separation of dinitrile compounds from a medium originating from the hydrocyanation of unsaturated mononitriles. The invention consists in feeding the medium comprising the dinitriles to a distillation column and then recovering the purified dinitriles as intermediate fraction, the heavy products being removed as column tail fraction and the light products, including the unsaturated mononitriles, being recovered as top fraction.

Abstract: The invention relates to a process for recovering 3-aminomethyl-3,5,5-trim-ethylcyclohexylamine (isophoronediamine, IPDA) having a fractionally distilled cis/trans isomer ratio of at least 73/27. The process includes the following steps: a) providing IPDA in a cis/trans isomer ratio of <73/27; b) feeding IPDA into the middle region of a distillation column having internals and distilling the IPDA in this distillation column at a temperature of from 5 to 300.degree. C.

Abstract: Process for working up a bottom stream wherein high boilers and ionic liquid from an extractive rectification in which the ionic liquid is used as entrainer. The process includes feeding the bottom stream to an evaporation stage which is operated at a pressure of less than 500 mbar or to a stripper which is operated through use of inert gas or steam, and the major part of the high boiler present is separated off in vapor form from the ionic liquid.

Abstract: The present invention relates to a new process for obtaining fatty acids with improved color, odor and heat stability which is characterized in that: (a) in a first step the crude acids are fed to a rectification (“precut”) column in order to remove low boiling by-products being present in the starting material as a top fraction, and (b) in a second step the bottom fraction of the precut column is fed to a sidestream column in order to obtain the pure fatty acids as the side fraction, to remove low boiling by-products which have been formed in the course of the first distillation as a top fraction and to remove high boiling by-products, either being present from the starting material or formed during the first distillation, with the residue.

Abstract: This invention relates to a separation process comprising (i) introducing a vapor phase mixture into a condensing apparatus, said vapor phase mixture comprising at least one desirable component and at least one undesirable component; (ii) controlling the temperature in the condensing apparatus utilizing a heat-transfer gas; and (iii) operating the condensing apparatus at a temperature and a pressure sufficient to selectively condense at least a portion of said vapor phase mixture and thereby yield a recovered content containing said at least one desirable component. The separation process is useful in semiconductor applications such as recovery of unreacted organometallic compound precursors in chemical vapor deposition or atomic layer deposition processes.

Abstract: The present invention provides a continuous process for recovering acetone from a waste stream from an acetone purification stage. The waste stream contains mesityl oxide and optionally acetone. The process for recovering acetone includes separating the waste stream in a separating device at least in one stream containing mesityl oxide and optionally a further stream containing acetone, then concentrating mesityl oxide in the mesityl oxide containing stream, and finally 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: An improved process for the separation of carbon dioxide from the flue gas of an oxy-combustion power plant is provided. The flue gas is compressed, cleaned, cooled and dried. This clean, compressed dry flue gas is then further cooled, partially condensed and separated into liquid and vapor streams. The liquid streams, which contain a high concentration of carbon dioxide, are vaporized, compressed and exported to an end user. The vapor streams are heated and expanded, in order to extract useable energy. At least two expanders are used to extract this energy, with an intermediate warming step.

Abstract: Crude water-containing tetrahydrofuran is purified by passing the crude tetrahydrofuran through three distillation columns, withdrawing water from the bottom of the first column, recycling water-containing tetrahydrofuran from the top of the second column into the first column, passing a sidestream of the first column into the second column, recycling the bottom product of the third column into the first column, and withdrawing a distillate at the top of the first column. Additionally, a sidestream of the second column is passed into the third column and the purified tetrahydrofuran is recovered as the top product of the third column.

Abstract: A formaldehyde-containing product is separated from a formalin solution containing formaldehyde, water, and methanol by distilling in the presence of a water entraining compound, especially methyl propionate or methyl methacrylate. The product contains substantially less water than in the solution and may be used, for example, in a further process which requires a source of formaldehyde containing a relatively low level of water, for example, the catalyzed reaction of methy propionate with formaldehyde and methanol to produce methyl methacrylate.

Abstract: A method for purifying a precursor material for use in a chemical vapor deposition system comprising providing a precursor material suitable for chemical vapor deposition, and distilling the precursor material to provide, as a distillate, a purified precursor material from which at least one non-volatile component, at least one metal impurity, or a combination thereof has been removed. The method may be used to purify siloxane and silane precursor materials and reduce clogging of chemical vapor deposition components.

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