Abstract: The invention provides a means for greatly saving the thermal energy consumption in the dehydrating distillation of an aqueous solution of a carboxylic acid such as acetic acid by use of an azeotropically distilling entrainer boiling at a lower temperature than the carboxylic acid and immiscible with water. The improvement proposed by the invention comprises taking at least a part of the entrainer phase separated from the condensate coming from the column top or at least a part of the side-cut fluid abstracted from the refluxing fluid inside the column, evaporating the thus taken fluid into vapor and introducing the vapor into the distillation column at a stage for the introduction of the starting feed or below.

Abstract: An improved process for purification of glycerol obtained from natural sources comprising alkalizing a glycerol-containing crude mixture in the presence of air for oxidation, evaporating the mixture in a thin-layer evaporator with redistillation of the residue, rectification and reevaporation in a packed column characterized by low-pressure-loss plates with a falling-film evaporator designed for internal and external partial condensation and to separate off unwanted constituents of the mixture, bleaching the product with activated carbon and separating the bleach in known manner.

Abstract: Isoprene is recovered from a C.sub.5 -hydrocarbon mixture containing isoprene, penta-1,3-diene and cyclopentadiene by separating the said mixture by liquid-liquid extraction or extractive distillation with the aid of a selective solvent, in combination with a distillation upstream or downstream from the liquid-liquid extraction or extractive distillation, by a method in which a stream containing penta-1,3-diene and cyclopentadiene is separated off in the upstream or downstream distillation and is catalytically hydrogenated, and the hydrogenated stream is fed to the upper part of the liquid-liquid extraction or extractive distillation.

Abstract: For the distillation of a stream consisting essentially of alcohols of 6-20 carbon atoms, water and methanol, the methanol is first separated from the homogeneous, aqueous solution as the overhead product by distillation under a head pressure of 500-1,000 mbar. The bottoms discharge is mechanically separated under normal pressure and at a temperature of 5.degree.-95.degree. C. in a phase separator to obtain a discrete water phase preferably containing at least two thirds of the feedstream water. The remaining organic phase is then transferred from the phase separator into a second distillation column and the organic phase is dewatered in the latter at 100-500 mbar. The head product from the second column is conducted to a second phase separator; the aqueous phase is separated therein at a temperature of 5.degree.-95.degree. C. and optionally returned into the first phase separator. The bottom product from the second distillation column is passed into a downstream distillation stage wherein the C.sub.6 to C.

Abstract: A method of distillation employing a heat pump (which may be driven by a compressor) using a vapor stream from within the distillation system as a heat source and a liquid stream from within the distillation system as a heat sink. The selection of heat-source vapors and heat-sink liquid is such that at least one is withdrawm from the phase-contacting region of the distillation system. The return of streams withdrawm from the phase-contacting region of the distillation system to the distillation system is such that at least one of the streams is returned at a temperature different from that of the point from which it was withdrawn, and all withdrawn streams are returned in manner such that a stream removed as vapor is returned at a point with a temperature at most that at the point it was withdrawn, and a stream removed as liquid is returned at a point with a temperature at least that at which it was withdrawn.

Abstract: The recovery of an acetic acid product of low brominated organics content can be made from the liquid effluent from n-butane oxidation with oxygen gas in the presence of an acetic acid solution containing ion of bromine in combination with ions of cobalt or with ions of manganese and cobalt. Such recovery is made not by the use of a series of separate fractionation towers but rather by the use of a single fractionation tower having a top rectification zone, an intermediate stripping zone with a feed inlet at the top thereof and a bottom reboiler zone below the stripping zone wherein the acetic acid product is removed as a vapor product from said stripping zone below said feed inlet but above the reboiler zone.

Abstract: Fractionation method and apparatus are provided, wherein heavy product is withdrawn from a first fractionator and introduced into a second fractionator, which operates in a predetermined moderate pressure range. The withdrawn heavy product is separated into relatively light ends and relatively heavy ends by introducing stripping vapor into a lower section of the second fractionator. A controlled stream of light product quench, including bottoms product from the stripper, is introduced at a predetermined low temperature and a predetermined variable flow rate to the second fractionator to adjust an end point of overhead products exiting therefrom. Second fractionator overhead product is passed into the stripper, and light components from the first fractionator are introduced into the stripper, such that overhead products from the second fractionator strip light ends from the relatively light product components from the first fractionator.

Abstract: Process is disclosed for treating the reaction product of propionic acid and formaldehyde to recover methacrylic acid from an aqueous effluent wherein said effluent contains methacrylic acid, unreacted formaldehyde, unreacted propionic acid, water and by-products.

Abstract: In fractionating a gaseous mixture, e.g. an acid gas and hydrocarbon, in a column wherein, during distillation, components of the gaseous mixture tend to form a substantially azeotropic mixture, or at least one of the components of the gaseous mixture tends to freeze out, withdrawing a side stream fluid from the column during fractionation, and separating said side stream fluid, e.g. by membranes or scrubbing, so as to remove preferentially at least a portion of one of the components of the substantially azeotropic mixture, or of at least one of the components tending to freeze out, and recycling resultant depleted side stream to said fractionating column.

Abstract: Methacrylonitrile higher in purity than that obtained by the conventional process is efficiently produced by the present improved process for producing purified methacrylonitrile in which the reaction mixture formed by the ammoxidation of isobutylene or tert-butyl alcohol is distilled using water as solvent to obtain a crude methacrylonitrile solution which contains methacrylonitrile as major constituent, methacrolein, hydrogen cyanide, and isobutyronitrile, and the crude methacrylonitrile solution is then purified in a product column, wherein the improvement comprises first removing isobutyronitrile from said crude solution, then feeding the remaining solution to the product column, withdrawing from the top a vapor containing methacrolein, condensing the vapor, returning a greater part of the condensate to the product column while removing the remainder from the distillation system, and withdrawing purified methacrylonitrile from the middle or lower section, preferably from a point lower than the feeding sta

Abstract: A process for the nondegenerative distillation of C.sub.6 -C.sub.24 -fatty acids, of the type obtained by splitting natural fats and oils or by synthetic processes, such as for example the oxidation of paraffins, the crude product is thermally dried under reduced pressure, the dried and heated crude product is subjected to fractional evaporation in falling-film evaporators, optionally in the presence of superheated steam, and the various vapor fractions are deposited in condensers. The thermal drying process is conducted at a temperature of 60.degree.-80.degree. C. and a pressure of 90-100 mbars. The de-watered crude product is fractionated in a film-forming evaporator and, after distillation, passes to a rectification column which condenses the low boiling constituents as the main runnings.

Abstract: The invention relates to a process for the production of grade AA methanol by distilling raw methanol in several distillation stages, for separating grade AA methanol, tail gas, and fusel oil from the raw methanol and further processing the fusel oil to produce additional methanol of grade AA quality at a return ratio of 5:1 or higher.

Abstract: Improved process for the separation of a hydrocarbon-containing feedstream comprising monomer, comonomer and diluent into separate product streams which comprises subjecting the feedstream to two-stage distillation provided with a common accumulation zone wherein the condensate from the accumulation zone serves as the source of feed for the second distillation and reflux for the first distillation. In a specific embodiment, a feed comprising ethylene, 1-hexene, and isobutane is separated into separate streams of 1-hexene, ethylene and isobutane, and isobutane for recycle to polymerization.

Abstract: A two-stage distillation method for separating a mixed liquid such as a dimethylformamide-containing aqueous liquid or a methanol-containing aqueous liquid, into light and heavy fractions. The mixed liquid is first subjected to a distillation treatment in a first distillation zone of a vapor recompression type. When the boiling point of the mixed liquid is close to that of the desired light fraction, the top product from the first distillation zone is recovered as the light fraction, while the bottom product is subjected to a further distillation treatment to obtain the heavy fraction as its bottom product. When the boiling point of the mixed liquid is close to that of the heavy fraction, the bottom product from the first distillation zone is recovered as the heavy fraction, while the top product from the first distillation zone is subjected to a further distillation treatment to obtain the light fraction as its top product.

Abstract: A process for producing dimethyl ether useful as a propellant by dehydrating methanol and recovering dimethyl ether from the dehydrated product by distillation, which comprises(A) a reaction step wherein the dehydration reaction of methanol is conducted in a vapor phase under pressure of from 2 to 50 kg/cm.sup.2 G in the presence of a solid acid catalyst,(B) a first distillation step wherein the reaction mixture formed by the above reaction step is cooled and introduced into a pressurized distillation column under pressure of at least 5 kg/cm.sup.

Abstract: A desired separation between sidedraw product streams withdrawn from a fractional distillation column is maintained by controlling the flow rate of the external reflux associated with a particular sidedraw product stream in response to the output signal from a temperature controller which is reset by an internal reflux controller. Such cascade control improves the stability of a fractionation process and provides for good control of the separation between sidedraw product streams.

Abstract: In a fractional distillation process in which a sidedraw product stream is withdrawn from the fractional distillation column, the flow rate of the overhead product stream is controlled so as to increase the flow of the upper external reflux so as to drop as much as possible of the overhead product into the sidedraw product stream. However, valve position control is utilized to override the control of the flow of the overhead product stream, which is being controlled so as to substantially maximize the flow of the sidedraw product stream, if the valve controlling the flow of the upper external reflux approaches fully open such that control of the liquid level in the overhead accumulator associated with the fractional distillation process is not lost.

Abstract: The reaction product from etherification of C.sub.4 -C.sub.7 isoolefins with methanol in the presence of an acidic catalyst is washed with water in the presence of inert hydrocarbons thereby removing methanol and a part of the tertiary alcohol. The aqueous extract solution bottoms is distilled to separate methanol as overhead. Tertiary alcohols are withdrawn as a side stream from a tray of the distillation column with a high concentration thereof and fed into the washing column.

Abstract: In purifying methyl methacrylate by feeding a feed mixture containing methanol, methyl methacrylate and 0.

Abstract: The invention pertains to improvements in a fluid handling system in which a working fluid passes through a rotor while undergoing a pressure change. A shaft extends longitudinally from and rotates with the rotor. A first seal surrounds the shaft in axially spaced relation to the rotor, and a lubricant having a minimum boiling point is injected into the first seal adjacent the shaft at a pressure sufficient to cause the lubricant to flow axially toward the rotor. A housing surrounds the rotor and shaft and defines a contact zone between the rotor and the first seal for receiving both lubricant and a contact fluid such as the working fluid or a seal buffer gas used to isolate the working fluid from the lubricant. The contact fluid has a maximum boiling point substantially less than the minimum boiling point of the lubricant.

Abstract: Methanol and cyclohexane are recovered from a condensed methanol-cyclohexane azeotrope by allowing the condensed azeotrope to separate in a vessel into an upper phase rich in cyclohexane and a lower phase rich in methanol, fractionating the upper phase in a first column whereby the methanol-cyclohexane azeotrope is taken off the top and returned to the vessel while cyclohexane is removed from the lower portion of the first column, and fractionating the lower phase in a second column whereby the methanol-cyclohexane azeotrope is taken off the top and returned to the vessel while methanol is removed from the lower portion of the second column.

Abstract: Aldehydes are obtained from the gaseous product of the hydroformylation of olefinically unsaturated compounds using a rhodium catalyst by a process (cf. FIG. 2) in which(a) this gaseous product is introduced, without being cooled or depressured, into a distillation column D,(b) the top fraction from this column is cooled in a condenser K so that the greater part of the aldehydes contained therein is condensed,(c) the condensate is separated, in a separator A, into a gas phase and a liquid phase,(d) the gas phase from A, after waste gas has been separated off, is again brought to the hydroformylation pressure by means of a compressor P, and is returned to the reactor as a recycle gas,(e) the liquid phase from A is returned to D, and(f) the aldehydes are taken off from column D as liquid bottom products and/or as a vaporous side stream.

Abstract: Normal butane withdrawn from the main fractionator in an acid alkylation process is recycled to the main fractionator as required to insure that the actual alkylate to normal butane ratio in the alkylate product withdrawn from the main fractionator does not go below a desired ratio. Maintenance of the actual ratio at or above the desired ratio substantially minimizes the concentration of isobutane in the alkylate product stream.

Abstract: Ethanol is produced continuously via the carbonylation of methanol, by(a) carbonylating methanol, in a reactor R, in the presence of a carbonyl complex of a metal of group VIII of the periodic table and of a halogen compound,(b) separating, in a distillation column D1, the reactor discharge, into a top fraction comprising methyl acetate, methanol, dimethyl ether and an organohalogen compound, and into a bottom fraction comprising water, small quantities of acetic acid and the catalyst, if the latter is not in a fixed bed, the residence time being so adjusted that the greater part of the acetic acid reacts with the methanol present to give methyl acetate,(c) separating the top fraction from D1, in a distillation column D2, into a top fraction comprising small quantities of methyl acetate, methanol, dimethyl ether and the organo-halogen compound, and a bottom fraction comprising methyl acetate and methanol, and recycling the top fraction to reactor R,(d) distilling off, via the top of distillation column D3, th

Abstract: A process for isolating isobutene from C.sub.4 -hydrocarbon mixtures containing isobutene by reacting the mixture with a primary alcohol in the presence of an acid condensing agent, to form the tertiary ether, separating off the unconverted hydrocarbons and decomposing the tertiary ether in the presence of an acid catalyst at an elevated temperature, wherein a primary C.sub.3 - or C.sub.4 -alcohol is used and the temperature at which the reaction mixture leaves the etherification stage, in which the tertiary ether is formed, is lower than the mean temperature in the etherification stage.

Abstract: This invention relates to a process for purifying crude ethanol, whether produced by fermentation or by the synthetic route, to produce a pure ethanol-water azeotrope. The process uses only two distillation columns for fermentation ethanol or synthetic ethanol eventhough the latter has diethyl ether as impurity. The inventive concept lies in the design and specification of the columns and the specific high pressure and low reflux ratio distillation conditions which enable each of the impurities in ethanol to be reduced below ppm. Ethanol of such purity is most desirable when used for potable or pharmaceutical purposes.

Abstract: A process for producing an unsaturated nitrile with saved energy by which the bottom stream from a recovery column is used as the heat source for at least one distillation column in the process and thereafter used to pre-heat a recovery column feed withdrawn from the bottom of an absorption column, characterized in that the bottom stream of the absorption column is previously heated by at least one source of waste heat in the process, the source being selected from (1) the circulating water in the quenching column, (2) the overhead vapor of the absorption column, (3) the overhead vapor of a dehydration column and (4) the overhead vapor of a product column.

Abstract: An improved distillation method and apparatus are provided for recovering anhydrous ethanol from fermentation or synthetic feedstocks. The system includes at least one stripper-rectifier tower, a dehydrating tower, and an azeotropic agent stripping tower. Substantial energy savings are realized by operating the dehydrating tower, and preferably also the azeotropic agent stripping tower, at a higher pressure than the stripper-rectifier tower and by condensing the overhead vapors from the dehydrating tower (or dehydrating tower and azeotropic agent stripping tower) to provide the heat required in the stripper-rectifier tower. In a preferred embodiment, two stripper-rectifier towers are used, one operating at a higher pressure than the other, in which case the higher pressure tower is heated as just described and the overhead vapors from the higher pressure tower are condensed to supply the heat required in the lower pressure tower.

Abstract: Excess water and color-forming materials present in crude 1,4-butanediol are reduced by subjecting the crude 1,4-butanediol to distillation under conditions wherein substantially all the water present in the crude 1,4-butanediol is first removed and then the 1,4-butanediol with reduced water content is further refined by flash evaporation under vacuum.

Abstract: A method for working up residues of an extractive distilling process for obtaining pure hydrocarbons. The residue from an extractive distilling column is fed to the about middle part of a distilling column. The hydrocarbons are distilled and removed at the head of the distilling column and the solvent is removed at the bottom of the distilling column. A sidestream is removed from the distilling column at a position above the feed plate for the residue from the extractive distilling column via a so-called reflux evaporator plate having an elevated level of liquid. The sidestream is heated by indirect heat exchange with the solvent flowing from the distilling column. The heated-up sidestream is fed back into the distilling column at a level at or above the reflux evaporator plate. The concentration of the solvent at the reflux evaporator plate is controlled by the amount of reflux at the head of the distilling column.

Abstract: The invention provides a process for the recovery and purification of acrylonitrile from acetonitrile and relatively heavy impurities mixture by water extractive distillation and solvent stripping wherein the mixture is fed to approximately the middle of a recovery column, a primary solvent water stream is added to the top of this column and a secondary solvent water stream is added to a point intermediate the mixture feed point and the top of the recovery column; a recovery column bottoms stream comprising water, acetonitrile and acrolein is removed from the bottom of the column and is added to a stripper column; acetonitrile is removed from the upper portion of the stripper column, a primary solvent water stream is removed from the bottom of the stripper column and is sent to the top of the recovery column as the source of the added primary solvent water stream and a secondary solvent water stream is removed from an intermediate point of the solvent stripper and is sent to the recovery column as the source

Abstract: In a process for producing butadiene or isoprene having a high purity comprising a step of treating a C.sub.4 or C.sub.

Abstract: An improved adsorption-desorption separation process is disclosed for separating close boiling fractions or isomers of a hydrocarbon feedstream containing mixed hydrocarbon fractions or isomers.

Abstract: A process is described for the recovery and purification of an olefinic nitrile, such as methacrylonitrile, from mixtures of said olefinic nitrile with hydrogen cyanide, acetonitrile, acrylonitrile, and carbonyl compounds, which result from the ammoxidation of an olefin, such as isobutylene. The mixtures of olefinic nitrile are fed to an extractive distillation column at a point above the middle of the column, a vapor sidestream is removed at a point below the middle of the extractive distillation column said sidestream containing substantially all of the hydrogen cyanide, acetonitrile and carbonyl compounds and then concentrating the hydrogen cyanide, acetonitrile and carbonyl compounds in a stripping pot.

Abstract: An apparatus unit for the fractional distillation and rectification of liquid mixtures includes a plurality of horizontal superimposed tubular main sections interconnected in series by a plurality of tubular connecting sections, e.g. U-shaped, to define an elongated space along which liquids and vapors flow. Intimate contact between liquids and vapors and efficient heat and mass transfer are provided by a stirrer rotating within the main section about horizontal axes and magnetically driven from the outside. Suitable inlet and outlet ports and heating and cooling devices are provided. An arrangement for joining the adjacent sections without the use of flanges or threaded portions is provided. A number of such units are preferably associated to form a modular apparatus, the individual units being operatively connected as desired to provide series, parallel or mixed flow of the fluids.

Abstract: In a process for the continuous preparation of adipic acid by hydrolysis of C.sub.1 -C.sub.4 -alkyl adipates with water at an elevated temperature in the presence of a strongly acidic ion exchanger, the improvement that the esters and excess water are fed to the middle section of a column, reaction mixture is taken off at a plurality of trays of the column below the feed point, passed over a strongly acidic ion exchanger and recycled, alkanols or alkanol/water mixtures are taken off at the top of the column and an aqueous solution of adipic acid is taken off at the bottom of the column.

Abstract: A process and apparatus for the separation of components from a mixture which forms an azeotrope is disclosed by subjecting the mixture to extractive distillation to remove one of the components and regeneration to separate another component from the extracting agent added to the extractive distillation column. According to the invention, a first side stream is withdrawn from the extractive distillation column, passed in heat exchange with the bottoms from the extractive distillation column en route to the regeneration column and returned to the extractive distillation column at a point below the point at which it is withdrawn. A second side stream from the extractive distillation column is withdrawn, passed in heat exchange with the bottoms of the regeneration zone and returned to the extractive distillation column. For this purpose, separate heat exchangers are used for the respective side streams.

Abstract: A control system for distillation column with a sidedraw line is provided wherein a prediction on the influence by changes in the feed stream with respect to the sidedraw composition is made.

Abstract: Formaldehyde manufacture by oxidative-dehydrogenation of methanol over a silver or copper catalyst. Aqueous formaldehyde solution is obtained from the reaction and is stripped of methanol and water by a low energy process at relatively low temperature by means of recycled inert gas in a stripping column comprising at least about 1.5 theoretical transfer units for stripping methanol.

Abstract: Pure acetone is recovered from a crude acetone vapor fraction removed overhead from a first column separating phenol and higher boilers as a bottom fraction from a cumene hydroperoxide cleavage reaction product by partially condensing the crude acetone fraction, returning the condensed portion of the crude acetone fraction to the first column as reflux, feeding the remaining portion as a vapor to an intermediate point in a second distillation column to which there is also fed continuously at a point above the acetone feedpoint a dilute aqueous solution of an alkali, removing from the base of the second column a residue fraction comprising compounds boiling above acetone, removing from a point in the second column intermediate; between the alkali feedpoint and the top of the column as a liquid sidedraw fraction pure acetone having a permanganate time (PT) greater than 4 hours, and removing from the top of the second column as a vapor fraction acetone having a PT less than that of the sidedraw fraction, condens

Abstract: A purification process for monomers and solvents used in the production of polymers by solution polymerization comprises supplying impure monomer and solvent to a distillation column which rejects light and heavy impurities from the top and bottom respectively and which dries the monomer-solvent mixture by azeotropic distillation, and withdrawing a pure monomer solvent vapor as a side stream from a point intermediate the top and bottom of the column.

Abstract: A multi-stage evaporator is used to remove water from the extracted distillation or stripper tower bottoms recycled as quench liquid to the quench tower of an acrylonitrile purification and recovery system. This results in a significant decrease in the amount of waste quench tower bottoms produced by the system. Use of a multi-effect evaporator represents a significant energy savings as compared with other techniques for decreasing the water content of the recycle stream.

Abstract: A method for separating a mixture of reaction products produced in the catalytic etherification of a lower isoolefin with methanol wherein said reaction product comprises a mixture of ether, methanol, unreacted hydrocarbon and tertiary alcohol which comprises adding water to said reaction product to form a hydrocarbon phase containing said ether and an aqueous phase containing methanol and a tertiary alcohol, separating said hydrocarbon phase to recover a methyltertiary alkyl ether, introducing said alcohol-containing aqueous phase into a distillation column to separate a methanol fraction overhead, withdrawing a side stream rich in tertiary alcohol from said distillation column, stripping this side stream in a stripping column to separate a second methanol fraction overhead and a tertiary alcohol bottoms fraction and recycling the methanol overhead fraction from the stripping column to the upper part of the distillation column and recycling the overhead methanol fraction from the distillation column to the f

Abstract: A process is disclosed for the recovery of a cumene/alpha-methylstyrene fraction from a mixture thereof with phenol and water. Said mixture is introduced into a fractionation column at conditions to separate an overhead fraction comprising cumene and alpha-methylstyrene and a phenol bottoms fraction. A vapor stream comprising cumene, alpha-methylstyrene and a phenol-water azeotrope is withdrawn from an intermediate level of said column and condensed to form an organic phase and an aqueous phase comprising phenol. The latter is discharged, and the former is recycled to the column. The overhead fraction thus requires substantially less caustic to neutralize the residual phenol container therein.

Abstract: A process for the continuous separation of methanol and water from a feed mixture containing predominantly tetrahydrofuran admixed with water, methanol and small amounts of additional compounds, in a rectifying apparatus having at last two rectifying columns, of which two are operated at different pressures which involves feeding the raw material into a first column operated under lower pressure, and introducing the distillate from the column operated under a lower pressure to a second column operated under a higher pressure, while a product stream from the second column operated under a higher pressure is reintroduced into the first column operated under a lower pressure.

Abstract: An apparatus for purifying impure vaporizable liquid, e.g. heavy water, which provides for the removal of dissolved inorganic solid contaminants from such liquid to produce a high purity liquid product.

Abstract: Process for purifying crude ethanol, whether produced by fermentation or by the synthetic route, to produce a pure ethanol-water azeotrope. The process uses only two distillation columns for fermentation ethanol and only three columns for synthetic ethanol because the latter has diethyl ether as impurity. The inventive concept lies in the design and specification of the columns and the specific distillation conditions which enable each of the impurities in ethanol to be reduced below 1 ppm. Ethanol of such purity is most desirable when used for potable or pharmaceutical purposes. The crude ethanol is fed into a first column and water is separately fed there as well, a side stream of purified aqueous ethanol is withdrawn from the first column and fed to a rectification column where a substantially pure ethanol-water azeotrope is withdrawn as a side stream. The points of introduction and removal of the respective streams to and from the columns are critical for a successful operation and product recovery.

Abstract: An improved process of distilling a cyclohexanone-rich overhead stream in a first still from a feed mixture comprising cyclohexanone, phenol and cyclohexanol of the type wherein a cyclohexanone-rich stream is withdrawn as a part of an overheads condensate from the first still and a phenol-rich stream is withdrawn as a part of a reboiled bottom stream from the first still. The improvement includes withdrawing a side stream substantially free of phenol from above the point where the feed mixture is fed to the first column and separating the side stream in a second still into a second cyclohexanone-rich overhead stream and a bottom stream containing cyclohexanone and cyclohexanol. The second cyclohexanone-rich stream may be returned to the first still.

Abstract: An improved distillation method and apparatus are provided for recovering hydrous ethanol from fermentation or synthetic feedstocks. Substantial energy savings are realized by utilizing a pair of stripper-rectifier towers in which overhead vapors from one tower operating at a higher pressure supply the heat required for the other tower operating at a lower pressure and by preheating the feedstock in multiple heat exchange steps. The feedstock is split into two portions of unequal size, the larger portion being supplied to the higher pressure tower and the smaller portion to the lower pressure tower.

Abstract: A process for the purification of olefine oxides by subjecting a mixture containing the olefine oxides to distillation in a distillation column in the presence of a small amount of water in order to obtain olefine oxide as the distillate. A fraction of the down-flow liquid is withdrawn from the column and the withdrawn fraction is subjected to decantation, so as to separate off an aqueous phase which is discarded, and an organic phase. The organic phase is returned to the column at a point located below the withdrawal point.