Abstract: A system, method and configuration for recovering turpentine during the manufacturing of wood chips, wood pellets or other substances that may include turpentine. In general, a turpentine recovery system is used to capture turpentine from exhaust of a dryer as wood chips are being dried. Advantageously, application of the various techniques disclosed herein can result in the recovery of turpentine that can then be sold to generate revenue and, may contribute to a reduction in the capital and operation costs for emission controls for the dryer exhaust.

Abstract: Solvent regeneration to recover a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a solvent-rich stream containing selective solvent, heavy HCs, and polymeric materials (PMs) generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives is provided. A combination of displacement agent and associated co-displacement agent squeezes out the heavy HCs and PMs from the extractive solvent within a solvent clean-up zone. Simultaneously, a filter equipped with a magnetic field is positioned in a lean solvent circulation line to remove paramagnetic contaminants. The presence of the co-displacement agent significantly enhances the capability of the displacement agent in removing the heavy HCs and PMs from the extractive solvent.

Abstract: Methods and apparatuses for extractive distillation using internal addition of steam to an extractive distillation column from a reboiler are described herein. The apparatuses include an extractive distillation column, a reboiler (for example, a kettle reboiler) coupled to the extractive distillation column, and a steam input line. The steam input line is coupled to an internal steam sparger device of the reboiler. Methods utilizing the apparatuses to perform extractive distillation of a hydrocarbon feed stream are also described herein.

Abstract: Systems and processes for recovering alkylene oxide, including an alkylene oxide recovery column including a stripping section located in the column to convert a portion of a feed stream to a gas phase including alkylene oxide; a reabsorption section in the column above the stripping section including a water stream to reabsorb the alkylene oxide in the gas phase portion and to produce an aqueous solution, a first stripping gas to strip carbon dioxide and oxygen from the aqueous solution by converting a portion of the aqueous solution to a gaseous portion, producing an alkylene oxide stream, and a side take-off located at a bottom portion of the reabsorption section for removal of the alkylene oxide stream; a condenser to partially condense the gas phase portion; and a top take-off for removal of a light impurity fraction.

Abstract: The present invention, known as The Bayliss Ranch Extraction Process, was developed for the production of hydrosols from botanical materials and involves extracting hydrosol by steam distillation. The two-stage process may be used with various botanical materials, including flowers, herbs, fruits, nuts, grasses, grains and vegetables. The process produces high quality hydrosol that can then be utilized by the consumer without further treatment, or used as a raw material in the manufacture of other products such as food, medicines and cosmetics.

Abstract: Methods of recovering free fatty acids having a low ester content from alkanol-containing solutions and oil mixtures containing tocopherols are disclosed which involve atmospheric or vacuum stripping at low temperatures. The recovered fatty acids have a high acid value, and have high commercial value in the production of high quality (high acid value) products, e.g., dimerized fatty acids, useful in polyamide resins.

Abstract: A process for the recovery of an acid in its anhydrous form from an aqueous solution containing the acid in its hydrated form. Adding to the solution a weak base in the form of a soluble salt of the acid and concentrating the solution containing the acid hydrate and the salt of the acid to a substantially water-free, acid-salt mixture. The acid is distilled off in its anhydrous form from the acid salt mixture.

Abstract: A method for recovering methanol from sulfur-based wood pulping process vapors, which contain at least methanol and dimethyl disulfide. The method involves three steps. The first step consists of introducing the vapors into a first distillation tower at a vapor introduction point. The second step consists of introducing water into the first tower at a point above the vapor introduction point. The third step consists of heating liquid which is in the first tower below the vapor introduction point so that a liquid stream flows from the bottom of the first tower and a gas stream flows from the top of the first tower. The liquid stream contains most of the methanol originally in the vapors. The gas stream contains most of the dimethyl disulfide originally in the vapors. The liquid stream can then be distilled in a second distillation tower by conventional distillation to produce dry methanol. The first and third steps can be combined by introducing sufficiently heated vapors.

Abstract: A process for purifying acetic acid which comprises: introducing a feedstock aqueous solution of acetic acid having an acetic acid concentration of from 10 to 50% by weight into an extractor; supplying an extracting medium containing isopropyl acetate in an amount from 0.6 to 3.

Abstract: In the manufacture of MTBE from TBA and methanol, acidic by-products formed during the etherification reaction are removed by fractionating the etherification reaction product in a first MTBE distillation column to provide a first lower boiling distillation fraction comprising isobutylene, MTBE, methanol and acidic by-products and a first higher boiling distillation fraction comprising methanol, TBA and water, fractionating the first higher boiling distillation fraction in a recycle distillation column to provide a lower boiling TBA recycle fraction and a higher boiling water fraction, recycling the higher boiling water fraction to the MTBE distillation column at a charge point above the charge point for the etherification reaction product, and adding aqueous sodium hydroxide to the recycled higher boiling water fraction in an amount sufficient to neutralize the acidic by-products charged to the MTBE distillation column.

Abstract: A process for the recovery of an acid in its anhydrous form from an aqueous solution containing the acid in its hydrated form. The process includes adding to the solution a weak base in the form of a soluble salt of the acid, and concentrating the solution containing the acid hydrate and the salt of the acid to a substantially water-free, acid-salt mixture. The acid is distilled off in its anhydrous form from the acid-salt mixture.

Abstract: Volatile acids containing metal salt impurities, such as metal pickling solutions-are regenerated by a process in which the acid is subjected to sulfuric acid distillation. Resulting volatile acid vapor is condensed and recycled to the pickle tank, while the residual acid mixture is treated in an acid sorption unit, preferably of the acid retardation type. Acid sorbed in the acid sorption unit is periodically eluted with water and recycled, while metal impurities are rejected in a deacidified by-product solution.

Abstract: The present invention provides a method for removing an organic compound in water at a high efficiency by separating an organic compound, particularly such an organic chlorine compound as 1,2-dichloroethane, carbon tetrachloride and chloroform dissolved in water or forming two liquid phases with water from a water phase, by the steps of:(i) charging water containing an organic compound into a first distillation column for conducting distillation or steam distillation to take the organic compound and water out of the top of the first distillation column and to obtain a bottom liquor containing the organic compound at a lower content from the bottom of the first distillation column, and(ii) charging the bottom liquor of the first distillation column into a second distillation column operated at a pressure lower than that in the first distillation column for conducting distillation, preferably flashing under reduced pressure, to take a gas distillate containing a large amount of the organic compound out of the t

Abstract: The present invention discloses a method to separate each component from a mixed solution of organic solvents obtained during the production of .alpha.-L-aspartyl-L-phenylalanine methyl ester, which is useful as a sweetener, namely, a mixed solution of acetic acid and toluene or a mixed solution of acetic acid, toluene and formic acid, recovering each component with a high recovery ratio with as small number of operations as possible. The method rationalizes the process and is highly valuable in practical use.

Abstract: Where side stream distillate strippers are used in the distillation of hydrocarbons, the required size of the distillation column and the amount of stripping gas or vapor required are reduced by passing components stripped from the distillates through a plurality of strippers in series, rather than directly back to the distillation zone.

Abstract: A process for separating acetone, dichloromethane and trifluoroacetic acid from a mixture of acetone, dichloromethane, and a trifluoroacetic acid/acetone azeotropeby (1) fractionally distilling the mixture of acetone, dichloromethane, and the trifluoroacetic acid/acetone azeotrope;(2) fractionally distilling the mixture of the trifluoroacetic acid/acetone azeotrope and free acetone;(3) adding at least about 16 parts of water to the trifluoroacetic acid/acetone azeotrope per 100 parts by volume of the trifluoroacetic acid/acetone azeotrope;(4) fractionally distilling the mixture of free acetone and the water/trifluoroacetic acid azeotrope;(5) adding at least about 10 parts of sulfuric acid to the water/trifluoroacetic acid azeotrope per 100 parts by volume of the water/trifluoroacetic acid azeotrope;(6) fractionally distilling the mixture of trifluoroacetic acid and the water/sulfuric acid complex.

Abstract: (CF.sub.3 SO.sub.2).sub.2 O is formed by reaction of CF.sub.3 SO.sub.3 H with P.sub.2 O.sub.5 and taken out of the reaction system by distillation, but the residue of the distillation contains a considerable amount of unreacted CF.sub.3 SO.sub.3 H. From the residue unreacted by adding water or a phosphoric acid solution, preferably the latter, to the residue to obtain a fluidic mixture containing an adequate amount of water and subjecting the mixture to distillation, preferably under reduced pressure at temperatures ranging from 180.degree. to 280.degree. C. It is possible to form additional CF.sub.3 SO.sub.3 H during the recovery process by adding a metal salt of CF.sub.3 SO.sub.3 H to the aformentioned mixture since the metal salt is decomposed by phosphoric acid contained in the mixture.

Abstract: The invention provides a process for producing essential oils by plant hydro-distillation including the following steps:(a) loading the plants continuously into a still where they are processed counterflow wise with steam,(b) continuous unloading of the exhausted plants,(c) recovery of the latent heat of distillation and condensation of the steam by means of a gas in a condenser,(d) drying of the exhausted plants by contacting with the gas, in a drying installation,(e) combustion of at least a part of the dried exhausted plants in a boiler and use of the combustion heat for producing steam.

Abstract: Practically anhydrous crude sec-butyl alcohol produced by catalytic direct hydration of n-butenes is freed by means of water from the azeotropically boiling and low-boiling by-products by continuous azeotropic distillation in a separation column, the prepurified anhydrous sec-butyl alcohol obtained is withdrawn and the high-boiling by-products are subsequently separated in a separate column.

Abstract: Distillation residues from the purification of caprolactam are worked up by heating in the presence of sodium hydroxide or potassium hydroxide and in the presence of a high-boiling hydrocarbon at from 250.degree. to 500.degree. C. and continuously removing the caprolactam.

Abstract: The present invention is a method for using water to remove amine from an oil-amine component. The oil-amine component is typically produced in prior art processes using an amine having an inverse critical solution temperature with water to break emulsions and sludges. The steps of the present invention include adding water to the oil-amine component in an amount sufficient to form a water-amine azeotrope with substantially all the amine in the oil-amine component followed by heating to remove the azeotrope. The method of the present invention may be used to remove amine from an oil-amine component even where the amine is present in an amount as low as 10% or less by weight.

Abstract: Crude phenol, containing AMS by-product, and MBF impurity, is distilled in the presence of water to separate MBF impurity.

Abstract: A process for purifying methanol which comprises introducing crude synthetic methanol obtained by catalytic reaction of carbon oxide and hydrogen into a rectifying column either as such or after it is first introduced into a topping column and distilled with or without the addition of water to remove low-boiling components from the top of the topping column, and distilling it in the rectifying column to withdraw purified methanol from the top of the column and mainly water from the bottom of the column; wherein an auxiliary distillation column is provided side by side with the rectifying column, and the rectifying column and the auxiliary distillation column are operated under particular conditions.

Abstract: Phenol containing MBF impurity is distilled in the presence of water and an extraction solvent for MBF (preferably AMS and/or cumene) to recover a phenol bottoms having reduced impurities. The use of solvent permits a reduction in the amount of water used, which reduces the amount of phenol in the overhead, thereby lowering costs.

Abstract: A flow of fermenting liquor from a fermentor is separated into a yeast concentrate flow, which is recirculated to the fermentor, and a yeast-free flow which is separated in a simple evaporator unit into a first ethanol-enriched vapor flow and a first liquid bottom flow. The first vapor flow is treated to produce the desired ethanol while a major part of the first liquid bottom flow is recirculated to the fermentor. A minor, residual part of the latter flow is fed to a stripping unit where it is separated into a second ethanol-enriched vapor flow and a second liquid bottom flow exhausted of ethanol.

Abstract: A process for continuous rectification of a liquid mixture containing alcohols, particularly a liquid fermate, employs a plurality of distillation columns to which the liquid mixture is fed in parallel, and which have successively reduced operating pressures and temperatures from an initial one to a final one thereof. The top vapor distillate from the higher-pressure columns supplies driving heat to the sumps of the next successively lower-pressure columns. Direct steam at 130.degree. C. to 160.degree. C. is fed to the sump of the column operated at the highest pressure. Direct steam is generated by indirect heat exchange of water with the top vapor withdrawn from the columns, and the resulting direct steam is fed to the sumps of the next-lower-pressure columns. The apparatus can also include a section for the production of absolute alcohol.

Abstract: A method of recovering light organic solvent from a liquid mixture containing the solvent and a product material, such as asphaltenes or coal liquefaction products. The solvent-product material mixture is treated to separate a first vapor phase rich in solvent and a first liquid phase rich in product material. The first liquid phase is then intimately contacted with steam, under shearing conditions, in a static or dynamic mixer. The steam-liquid phase mixture is then treated to separate a second vapor phase, rich in steam and solvent, and a second liquid phase, rich in product material and substantially depleted of solvent. Solvent is recovered from the first and second vapor phases.

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 process for recovering high purity resorcinol produced by the rearrangement of m-diisopropylbenzene dihydroperoxide in which the rearranged product mixture is neutralized, the neutralized mixture being filtered, the filtrate being admixed with toluene, the acetone being removed by distillation and the acetone-free rearranged product/toluene mixture being steam distilled to provide an aqueous resorcinol containing phase from which the resorcinol is recovered.

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: A vapor-liquid extractive distillation process utilizing a dialkyl sulfone containing 4 to 8 carbon atoms per molecule and at least one percent water as the solvent. The process according to this invention is of particular applicability in separating aromatics from nonaromatics in a BTX stream. The solvent system operates particularly well with relatively large amounts of water.

Abstract: A method of purification of crude .beta.-phenylethyl alcohol to give a highly pure .beta.-phenylethyl alcohol suitable as a perfume, which comprises subjecting the crude .beta.-phenylethyl alcohol to azeotropic distillation in the presence of an azeotropic solvent selected from water, an alkylene glycol, an alkylene glycol monoalkyl ether and a mixture of two or more kinds of these solvents, or extractive distillation in the presence of an extractive solvent selected from glycerine, an alkylene glycol, a polyalkylene glycol, an alkylene glycol monoalkyl ether, a polyalkylene glycol monoalkyl ether and a mixture of two or more kinds of these solvents.

Abstract: A flow of fermenting liquor from a fermentor is separated into a yeast concentrate flow, which is recirculated to the fermentor, and a yeast-free flow which is separated in a simple evaporator unit into a first ethanol-enriched vapor flow and a first liquid bottom flow. The first vapor flow is treated to produce the desired ethanol while a major part of the first liquid bottom flow is recirculated to the fermentor. A minor, residual part of the latter flow is fed to a stripping unit where it is separated into a second ethanol-enriched vapor flow and a second liquid bottom flow exhausted of ethanol.

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 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 improvement in the process for isolating and recovering meta- and para-cresols from crude cresol-containing compositions composed of cresol components, unreacted cymene components and high-boiling by-products, by distillation in a distillation zone, the characteristic features residing in that:(i) the unreacted cymene components content in the crude cresol-containing composition is adjusted to 5-25% by weight of said composition after the adjustment, and the water content of said composition is adjusted to become 0.17-1.

Abstract: A method for the removal of aromatic hydrocarbon from mixtures containing non-aromatic hydrocarbon by liquid-liquid extraction and extractive distillation is described. Isoenthalpic expansion of the rectification column bottom solvent stream and addition of water to the selective solvent can be used to reduce heat consumption.

Abstract: Process for isolating methyl tert-butyl ether contained in the reaction product of methanol with a C.sub.4 hydrocarbon cut containing isobutene, comprising fractionating said reaction product by introducing it at an intermediate point of a distillation zone, recovering methyl tert-butyl ether at the bottom thereof and, at the top thereof, a mixture of C.sub.4 hydrocarbons with methanol which is washed with water and condensed and wherefrom is separated a condensed C.sub.4 hydrocarbon fraction, a portion of which is fed back as reflux to the top of the distillation zone and another portion discharged, and separating the remaining water-methanol mixture by distillation.

Abstract: 2,2-Dichloro-5-methyl-1,1,1-trifluorohex-4-ene, an intermediate in the synthesis of pyrethroid insecticides, is obtained by continuous distillation, preferably under sub-atmospheric pressure, of a mixture of 5-methyl-2,2,4-trichloro-1,1,1-trifluorohexane, dimethylformamide and lithium bromide, precipitating the chlorofluorocarbons from the distillate with water and separating the desired product from starting material by a further distillation.

Abstract: In the recovery of energy from geothermal brines and other water containing or hot water sources, such brine or hot water under pressure is introduced into direct heat exchange contact with a working fluid such as isobutane, the resulting hot isobutane is expanded in a turbine to produce work, the turbine discharge is condensed and returned to the heat exchanger and the cooled brine is withdrawn from the column. The present invention is directed to recovery of working fluid dissolved and/or entrained in the spent geothermal brine or water withdrawn from the direct contact heat exchanger, including the steps of settling the brine in a settling tank to recover some of the isobutane, flashing the remaining brine to flash off additional isobutane and steam stripping the spent brine to drive off further isobutane, the recovered isobutane in each of the steps being recycled to the direct contact heat exchanger.

Abstract: An improved solvent recovery process comprising distilling soiled solvent in a main still and conducting hot solvent vapor through a heat exchanger associated with a tank in which an azeotropic mixture of water and soiled solvent is maintained, which mixture boils at a temperature lower than the boiling point of the solvent alone. A series of tanks feed soiled solvent to the azeotropic mixture tank and then to the main still, and heat exchangers fed by the vapor from the main still and the vapor from the azeotropic mixture tank pre-heat the soiled solvent. Automatic control of water injection into the azeotropic mixture tank in dependence upon the temperature of conductivity of the tank contents maintains the composition of the azeotropic mixture, the injected water being taken from separators which separate water from condensate of the main still and azeotropic mixture tank vapors.

Abstract: Process for separating benzene and/or toluene from mixtures thereof with saturated hydrocarbons, by extractive distillation using an aliphatic N-alkylamide as extraction solvent, comprising introducing in the distillation column, above the level of introduction of the extraction solvent, liquid water in an amount and under such conditions that said water is completely vaporized without substantially diluting the solvent, condensing the vapors discharged from the top of the column and dividing the resulting condensate into a phase of liquid saturated hydrocarbons, and a phase of water.

Abstract: In the recovery and purification of acrylonitrile or methacrylonitrile obtained by the ammoxidation reaction of propylene or isobutylene, the bottoms stream associated with the column for extractively distilling acrylonitrile or methacrylonitrile is both reduced in size and increased in polymer concentration by removing a vapor stream containing water from the lower fourth of said column, thus reducing the amount of solids-containing waste streams to be treated.

Abstract: A methanol production process including synthesis gas generation, methanol synthesis and methanol distillation includes an autonomous system in which low pressure steam is raised by heat exchange with a fluid stream at 120.degree.-300.degree. C. in the process, the low pressure steam is used as live steam to heat at least distillation column in the distillation section and bottoms water from a distillation column in that section is used as feed to the autonomous steam system.

Abstract: A water purification process is described for the removal of ammonia and optionally one or more acid gases from waste waters such as coke-plant or coal conversion waste waters. The process involves adding lime to these waste waters in amounts sufficient to react with fixed ammonia salts present in the waste water and to enable substantially all of the ammonia to be evolved upon distillation, adding a threshold amount of a scale inhibitor compound chosen from the class of certain organic phosphonates and subjecting the thus treated waste water to distillation to remove substantially all of the ammonia and acid gases present from the waste water. Preferably, this process is achieved by two separate and successive distillations. In this preferred process, the first distillation substantially reduces the amount of the acid gases and free ammonia. In the second distillation, the amount of fixed ammonia is substantially reduced.

Abstract: A water purification process is described for the removal of ammonia and optionally one or more acid gases from waste waters such as coke-plant or coal conversion waste waters. The process involves adding lime to these waste waters in amounts sufficient to react with fixed ammonia salts present in the waste water and to enable substantial amounts of the ammonia to be evolved upon distillation, adding a threshold amount of a scale inhibitor compound chosen from the class of certain organic phosphonates and subjecting the thus treated waste water to distillation to remove substantial amounts of the ammonia and acid gases present from the waste water. Preferably, this process is achieved by two separate and successive distillations. In this preferred process, the first distillation substantially reduces the amount of the acid gases and free ammonia and is conducted at a pH of more than 9. In the second distillation, the amount of fixed ammonia is substantially reduced.

Abstract: Dilute sulfuric acid contaminated with acetic acid and hydrogen chloride is purified with the resultant formation of concentrated sulfuric acid and acetic acid. To this end, the contaminated sulfuric acid is heated in a first step to at most 60.degree. C under 25-30 mm Hg so as to expel all of the hydrogen chloride together with minor proportions of acetic acid and water. In a second step, the sulfuric acid is heated to at most 165.degree. C under 20-25 mm Hg so as to distil off the bulk of acetic acid together with water. In a third step, the sulfuric acid is cooled down to 60.degree.-90.degree. C, diluted with 10-30 wieght % of water with agitation and while cooling is continued. Following this, the sulfuric acid is heated to 160.degree.-165.degree. C under 20-25 mm Hg and thereby freed from the water and residual acetic acid.

Abstract: A liquid feed stock containing oil is deodorized in a semicontinuous process wherein the feed stock, in a first evacuated chamber, undergoes heat exchange with a deodorized stock in a second evacuated chamber, said stocks being circulated in their respective chambers by upwardly flowing steam introduced into each chamber between a partition, separating the two chambers, and a guide plate parallel to said partition and spaced therefrom, whereafter said feed stock is passed through a succession of steam heating stages to heat said feed stock to successively higher temperatures thereby deodorizing the feed stock and then withdrawn as deodorized stock and recirculated as deodorized stock to said second evacuated chamber to undergo heat exchange with said feed stock.

Abstract: Impure methanol containing ethanol is substantially freed of ethanol by distilling a mixture consisting essentially of the impure methanol, ethanol and water with the aid of a distillation column in a region of which the methanol to water ratio is maintained substantially constant, and withdrawing a stream enriched in ethanol from a point near one end of that region.

Abstract: A crude alcohol-containing mixture comprising a saturated aliphatic alcohol of not more than three carbon atoms and associated impurities is processed in a three-tower distillation system to permit recovery of the desired alcohol product in highly concentrated and purified form. In the first tower the crude feed is subjected to extractive distillation with water to remove substantially all the impurities overhead. An aqueous bottoms stream from the first tower containing 5 to 10 wt.% alcohol and only minor amount of impurities is fed to the second tower where the alcohol product is concentrated and recovered. Overhead and intermediate purge streams containing low boiling and hgh boiling impurities are removed from the second tower and are fed to the third tower along with the overhead from the first tower. Stripped aqueous effluent is withdrawn from the bottom of the second tower and is recycled in part to the first tower.