Abstract: A free flow evaporator of the falling film type has the heating elements disposed in a circular configuration so that each extends radially a distance less than the interior radius of the evaporator cylindrical vessel. Heating vapor is introduced concentrically into the top of the vessel and passes into the tops of the heating elements, and condensate is withdrawn from the bottoms of the heating elements in the vessel. Excess vapor passes through a vapor vent in the bottom of the vessel. The boiling liquid, such as black liquor from paper pulp processing, is introduced through a header above an annular channel with a perforated plate bottom, the perforated plate being disposed on top of the heating elements. The evaporated liquid vapor passes radially outwardly in the vessel, and then upwardly, and is discharged from the top of the vessel and passes to the top of another vessel (providing another effect), to provide heating vapor to the other vessel.

Abstract: Liquids, such as juices, milk, molten metal and the like are concentrated by forming uniformly-sized, small droplets in a precision droplet forming assembly (14) and deploying the droplets in free fall downwardly as a central column within an evacuated tower (12) having cool walls (32). A portion of the solvent evaporates. The vapor flows to the wall (32), condenses, and usually flows down the wall as a film (62) to condensate collector (26) and drain (28). The vertical column of freely-falling droplets enters the splash guard (68). The condensate can be collected, sent to other towers or recycled.

Abstract: A method of recovering light organic solvent from a liquid mixture containing the solvent and a process material, such as asphaltenes or coal liquefaction products. The solvent-process material mixture is treated in a solvent separation zone to separate a first vapor phase rich in solvent and a first liquid phase rich in process material. At least a portion of the liquid in the solvent separation zone is transferred to a mixing zone, where the liquid is intimately contacted with steam, under shearing conditions. The steam-liquid phase mixture thus produced is returned to the solvent separation zone and treated to separate a second vapor phase, rich in steam and solvent, and a second liquid phase, rich in process material and substantially depleted of solvent. Solvent is recovered from the first and second vapor phases.

Abstract: A method and apparatus for improving the separation of a distillation system comprising a main distillation zone and at least one sidestream separation zone is described. The method comprises returning vapor separated in the sidestream separation zone to the main distillation zone at a location at least two trays and/or at least one theoretical stage above the liquid draw-off from the main distillation zone to the sidestream separation zone.

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: A problem has been identified which made it difficult, if not impossible, for the prior art to operate a reboiler in the mist flow regime. The invention which overcomes this problem is to provide a chamber to establish equilibrium between the vapor portion and the liquid portion of the reboiler effluent prior to introducing equilibrated vapor into the bottom of the distillation column. The invention is particularly useful for minimizing degradation of thermally sensitive materials.

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: A process for the multi-stage condensation of an overhead fraction is disclosed. The process facilitates optimal response to changes in distillation column controls wherein column top reflux condensation is preferentially returned to said distillation column, but auxiliary surge capacity is obtained by connection to a first accumulator section of an accumulating zone, which surge capacity is supplemented by one-way flow of liquid from a cooler, second section in said accumulation zone.

Abstract: An apparatus and method are provided for the fractional distillation of liquids in a fractionation column wherein cool liquids from the bottom tray of the column are effectively prevented from passing out directly with bottoms product before first passing through a reboiler. The column is of the type which includes a hollow shell having a surge baffle plate which divides a bottom portion of the shell interior into a first region and a second region. A separation baffle plate is provided which extends into the first region. At least one seal pan whose bottom is closely adjacent to the upper edge of the separation baffle receives liquids flowing from the bottom tray by means of a downcomer.

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: An apparatus for vaporizing a liquid and condensing the vapor includes at least one chamber in which the liquid is vaporized and at least one chamber in which the vapor is condensed. The apparatus has a conveyor inlet channel preferably at one end of the vaporizing chamber, and a conveyor outlet channel preferably at the opposite end of the vaporizing chamber. A conveyor for moving items to be treated through the apparatus extends through the conveyor inlet channel into the vaporizing chamber and out of the vaporizing chamber through the conveyor outlet channel. The apparatus includes a heat emitting device in the vaporizing chamber providing a surface temperature above the vaporizing temperature for substantially instantaneously vaporizing the liquid condensate maintaining a predetermined vapor level in the vaporizing chamber, and a cooling device in the condensate chamber for condensing the vapor.

Abstract: A distillation method and apparatus which comprises (a) a distillation zone adapted for the countercurrent contact of liquid and vapor, (b) a reboiler feed liquid compartment (c) means for directing distillation zone liquid into the reboiler liquid feed compartment, (d) a thermosyphon reboiler for partial vaporization of liquid thereto to produce reboiled vapor and liquid flows, (e) a conduit for the flow of liquid from the reboiler liquid feed compartment to the reboiler, (f) a reboiler return liquid compartment, (g) a conduit for the flow of reboiled liquid from the reboiler to the reboiler return compartment, (h) a conduit for the flow of reboiled vapor from the reboiler to the distillation zone, (i) means for communication of liquid by gravity flow between the reboiler feed compartment and the reboiler return compartment to provide substantially equal liquid levels in the two reservoirs, (j) a distillation zone liquid product compartment, (k) means for overflow of liquid from the reboiler return compartme

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: An apparatus for vaporizing a liquid and condensing the vapor includes at least one chamber in which the liquid is vaporized and at least one chamber in which the vapor is condensed. The apparatus has a conveyor inlet channel preferably at one end of the vaporizing chamber, and a conveyor outlet channel preferably at the opposite end of the vaporizing chamber. A conveyor for moving items to be treated through the apparatus extends through the conveyor inlet channel into the vaporizing chamber and out of the vaporizing chamber through the conveyor outlet channel. The apparatus includes a heat emitting device in the vaporizing chamber for vaporizing the liquid therein, and a cooling device in the condensing chamber for condensing the vapor.

Abstract: Mass transfer apparatus such as a distillation or rectification column which is divided so that the vapor flow is in two streams each in a separate zone, and wherein in each zone the liquid/vapor contacting stages have an inlet and an outlet disposed on opposite sides of an active area but to the same side of the division and such that liquid flow from the inlet across the active area to the outlet is generally rectiliner and parallel to the plane of the division, the locations of the stages in one zone being staggered axially relative to those of the stages in the other zone along the column and the liquid from each outlet being directed to an inlet of the next lower stage in the column whereby the liquid flow down the column is directed alternately from one zone to the other as it is passed successively from stage to stage down the column.

Abstract: A vapor generating and recovering apparatus for separating one component from a second component of a liquid solution and recovering one of the components comprising at least one chamber for generating vapor from the liquid solution and a condensing chamber for condensing the vapor. The at least one vaporizing chamber and condensing chamber being divided by an overflow weir having a controlled overflow area so that liquid solution will be caused to overflow at a preselected location along the length of the weir.

Abstract: An apparatus and method for vaporizing and recovering, by condensation, a composite liquid solution of at least two components having substantially different vaporizing temperatures. The apparatus includes at least one liquid condensate vaporizing chamber wherein the vapor of the lower vapor point component will be condensed from a vapor zone above the vapor zone of the vapor of the higher vapor point component. The apparatus further includes at least two weir or other means to define the vapor levels of each vaporized component and the condensing means for each component are disposed on the opposite side of the weir from the vapor zone.

Abstract: A vapor distillation system sprays a mixture of liquids to be distilled into an evacuated vaporizer chamber. The low boiling point components of the mixture will be vaporized while the remainder of the mixture will collect at the bottom of the vaporizer chamber. The collected liquid is recirculated and heated. The recirculating liquid is discharged, and fresh mixture is introduced, as a function of the sensed temperature of the recirculating liquid. The vapor is transferred to a condenser chamber having a water spray head so that the chilled spray condenses the vapor. Both the condenser chamber and the vaporizer chamber have fluid level control systems.

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 vapor generating and recovering apparatus for vaporizing a liquid and condensing a vapor, the apparatus including a container having a liquid therein with heating and cooling systems in heat transfer relation with the liquid and vapor in the container. The heating and cooling systems include means to vaporize the liquid and means to condense the vaporized liquid disposed within the container. Temperature or pressure sensing means in the cooling system is utilized to shut down the heating system when a preselected vapor level is exceeded.

Abstract: A process and apparatus for dewatering an ethanol-water solution is disclosed wherein a carrier gas is used to vaporize the solution and transport the vapors to a sorbent where water is sorbed in preference to ethanol. The invention is particularly suited for small-scale production of fuel-grade ethanol for blending with gasoline.

Abstract: An apparatus for generating at least two vapor zones, one above the other, by vaporizing a fluid mixture having at least two compounds therein having different vaporizing temperatures. The apparatus includes a chamber with vaporizing means, and vapor condensing means. Condensate recovery means is provided for recovering the condensed vapor and the condensate recovery means is in flow communication with a separation device for receiving the condensate from the condensate recovery means. The flow communication between the condensate recovery means and the separation device is external of the chamber. The separation means revaporizes the liquid with the lower vaporizing temperature for return to the vapor zone in the upper portion of the chamber and separates as a liquid the fluid having a higher vaporizing temperature.

Abstract: A method is disclosed for fractionating a hydrocarbon conversion zone effluent stream comprising at least three components which are to be isolated into separate streams. A two-column system for fractionating the effluent of a benzene alkylation zone is employed. The overhead vapor of a downstream second column is condensed in a side reboiler of a preceding recycle column. This side reboiler is located between the feed point to the recycle column and a separate reboiler located at the bottom of the recycle column. The utilities cost of performing the fractionation is reduced.

Abstract: Disclosed is a process for recovering a virtually water-free amine from an amine acid salt thereof. The process comprises a unique combination of phase separation stages practiced under mild heating and distillation stages. An amine product containing less than 0.2% water can be achieved by the present process. The feedstock for the process suitably is an acid scrub liquor used to scrub amine from a vapor stream thereof which has been used in a cold-box molding process in the foundry industry or in the cure of vapor permeation curable coatings in the coatings industry.

Abstract: Ethylene glycol is purified, particularly for fiber-grade applications, by removal of the residual ethylene carbonate from which the glycol was derived. The effluent from a reactor in which ethylene carbonate is hydrolyzed to ethylene glycol is distilled to produce a lower-boiling fraction comprising substantially ethylene glycol and water and a higher-boiling fraction comprising substantially ethylene glycol, higher glycols, and concentrated in hydrolysis catalyst. The higher-boiling fraction is recirculated to reflux against the lower-boiling product, thereby essentially completing the hydrolysis of unreacted ethylene carbonate thereby reducing the ethylene carbonate content of the ethylene glycol to very low levels suitable for fiber-grade applications.

Abstract: In the production of high purity phenol, a water-phenol mixture recovered from the top of a distillation column is contacted with a water immiscible solvent to extract methyl benzofuran and other by-products and impurities in phenol production therefrom, with the extraction being accomplished at a temperature at which the water-phenol mixture is present as a single phase liquid. The remaining mixture of phenol and water is recycled to the distillation.

Abstract: Mass transfer apparatus such as a distillation or rectification column which is divided so that the vapor flow is in two streams each in a separate zone, and wherein in each zone the liquid/vapor contacting stages have an inlet and an outlet disposed on opposite sides of an active area but to the same side of the division and such that liquid flow from the inlet across the active area to the outlet is generally rectilinear and parallel to the plane of the division, the locations of the stages in one zone being staggered axially relative to those of the stages in the other zone along the column and the liquid from each outlet being directed to an inlet of the next lower stage in the column whereby the liquid flow down the column is directed alternately from one zone to the other as it is passed successively from stage to stage down the column.

Abstract: A system for treating waste effluent and recovering solids and solvent material including a reservoir mounted on a stand connected by means to a solvent migrator including an adjustable trough for receiving new solution, a secondary reservoir with a cloth or absorbent material designed to contact the fluid in the secondary reservoir, while parallel to the sun's rays, an automatic leveling means and apparatus for recirculation of waste effluent including a leveling ball, and suction tubing for the recirculation of fluid, a solar unit comprised of glass panels to form a collecting dome with collecting troughs and a bonnet to shade the top of the pyramid formed by the dome panels and mirrors for the reflection of sunlight, all of which is connected to a chemical trap and subsequently a collecting means for the pure product.

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: A distillation method and apparatus which comprises (a) a distillation zone adapted for the countercurrent contact of liquid and vapor, (b) a reboiler feed liquid compartment (c) means for directing distillation zone liquid into the reboiler liquid feed compartment, (d) a thermosyphon reboiler for partial vaporization of liquid thereto to produce reboiled vapor and liquid flows, (e) a conduit for the flow of liquid from the reboiler liquid feed compartment to the reboiler, (f) a reboiler return liquid compartment, (g) a conduit for the flow of reboiled liquid from the reboiler to the reboiler return compartment, (h) a conduit for the flow of reboiled vapor from the reboiler to the distillation zone, (i) means for communication of liquid by gravity flow between the reboiler feed compartment and the reboiler return compartment to provide substantially equal liquid levels in the two reservoirs, (j) a distillation zone liquid product compartment, (k) means for overflow of liquid from the reboiler return compartme

Abstract: A process for the distillation and condensation of a multi-component liquid is described, the process being characterized by the utilization of a portion of the condensate in achieving increased separation of components of no-condensed vapor. In a principal embodiment, the overhead from a distillation column is cooled, condensing a portion thereof, and the condensed portion is accumulated in an accumulation zone. A first liquid stream is removed from the accumulation zone for reflux, while a second liquid stream is cooled, and then contacts, in a separate zone, the uncondensed portion of the overhead. The contacting absorbs and condenses components of the vapor, and the second liquid and absorbed components are collected in the accumulation zone.

Abstract: A process for the distillation and condensation of a multi-component liquid is described, the process being characterized by the contacting of a warm portion of the overhead vapor with a cool liquid portion of the overhead to achieve a higher accumulator liquid temperature. In a principal embodiment, a multi-component liquid is distilled, the overhead vapor is separated into major and minor portions, and the bulk of the major portion is condensed. Liquid is separated from the remaining vapor of the major portion, and the separated liquid is divided into major and minor fractions. The major fraction of liquid is collected in an accumulation zone, and is contacted in the accumulation zone with at least the bulk of the minor portion of overhead vapor. Vapor from the accumulation zone is contacted with the minor fraction of liquid in a contacting zone.

Abstract: A process for distilling and condensing a multi-component liquid is described, the process being characterized by the use of a portion of the uncondensed vapor in achieving more efficient heat utilization. In a principal embodiment, the multi-component liquid is distilled to produce an overhead vapor, and the vapor is condensed to produce a condensate and a partially cooled vapor. The partially cooled vapor is separated into major and minor portions, the bulk of the major portion is condensed to produce a condensation effluent, and the condensation effluent (comprising liquid or liquid and vapor) is contacted in a contacting zone with the minor portion of partially cooled vapor. The contacting produces a liquid which is collected in an accumulation zone.

Abstract: A process for distilling and condensing a multi-component liquid is described, the process being characterized by the use of a portion of uncondensed vapor in achieving more efficient heat utilization. In a principal embodiment, a multi-component liquid is distilled to produce an overhead vapor, the vapor is partially condensed, and the vapor-condensate is separated into a minor liquid fraction and a major vapor-liquid portion. The major vapor-liquid fraction is then separated into vapor and liquid, and the liquid therefrom is accumulated in an accumulation zone. The separated vapor is then contacted with the minor liquid fraction in a contacting zone, thereby absorbing the vapor and transferring its heat to the liquid fraction.

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: A C.sub.4 and/or C.sub.5 olefinic hydrocarbon cut, containing dimethyl ether and water as impurities, in a relative proportion of dimethyl ether to water of at most 5:1, is purified in a distillation zone where it is introduced at an intermediate level, distant from the top or from the bottom thereof by at least 3 theoretical plates, optionally with a stripping gas, and separated into a overhead fraction comprising an aqueous liquid phase and a hydrocarbon liquid phase at least partially recycled as reflux to the upper part of the distillation zone, and a bottom fraction formed of the purified C.sub.4 and/or C.sub.5 olefinic cut.

Abstract: Disclosed is a process for recovering a virtually water-free amine from an amine acid salt thereof. The process comprises a unique combination of phase separation stages practiced under mild heating and distillation stages. An amine product containing less than 0.2% water can be achieved by the present process. The feedstock for the process suitably is an acid scrub liquor used to scrub amine from a vapor stream thereof which has been used in a cold-box molding process in the foundry industry or in the cure of vapor permeation curable coatings in the coatings industry.

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: A method and apparatus for high volume distillation of impure liquid, particularly of binary mixtures of relatively low boiling organic substances and water, comprises fractionally distilling the impure liquid to form a vapor of a low boiling organic substance; compressing the vapor; passing at least a portion of the compressed vapor through a vapor composition adjustment zone wherein the organic substance may catalytically or otherwise react or merely stabilize following compression; compressing the vapor exiting the adjustment zone to form a recompressed vapor; cooling the recompressed vapor in heat transfer relation with the impure liquid whereby the vapor at least partially condenses, transferring sufficient heat to the impure liquid for evaporating the liquid and to form the aforementioned low boiling organic vapor; and collecting the condensed low boiling organic vapor.

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: Thermally coupled extractive distillation; a feed stock (for example, a C4 or C5 cut from an ethylene plant) is distilled by thermally coupled extractive distillation to remove paraffins and mono-olefins as a raffinate stream, as well as acetylenic hydrocarbons in a separate steam, thus segregating the C4 or C5 diolefin, the process using extraction solvents such as acetonitrile (ACN), dimethyl formamide (DMF), furfural, acetone, dimethylacetamide or N-methyl-2-pyrrolidone mixed with 0-12 weight percent of water, a bottoms stream of virtually acetylene free solvent further being produced; thermally coupled extractive distillation utilizing one to three coupled vessels to produce at least two and preferably three discrete, different volatility streams therefrom, as well as an extractive solvent recycle stream.

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: A method of purifying waste water, for example waste water from a coking plant, comprises supplying waste water to be purified to the upper part of a stripping column comprising a plurality of substantially horizontal plates disposed above one another, supplying vapor to the lower part of the column, and supplying a strong base to the column laterally at one or more levels, wherein the water to be stripped is passed downwardly from the top of the column across a number of successive plates sufficient to permit the pH of the water to decrease to a value below 7, and wherein the base is supplied at a level or levels lower than that at which the pH has decreased to the above value.

Abstract: It is the discovery of the present invention to provide an improved method of rectifying the crude production stream obtained by the vapor phase nitration of hydrocarbons by subjecting the absorber bottom mixture to extractive distillation with water.

Abstract: In a process for recovering pure methylal from methanol-methylal mixtures, which can optionally contain still further compounds, the separation conducted in a rectification device comprising two rectifying columns. In the first rectifying column, the mixture to be separated is rectified under a pressure lower than that in the second column, into a methylal-rich, methanol-poor distillate, and into a practically methylal-free, methanol-rich sump product. The methylal-rich distillate of the first rectification is then separated in a second rectifying column, operated under a higher pressure than the first rectification column, into a compound stream containing methanol and methylal, which is then recycled to the first rectifying column, and into pure methylal as the sump product.

Abstract: Liquid mixtures containing aliphatic alcohols are separated, by distillation, into a higher-boiling alcohol-containing fraction and a lower-boiling fraction containing the other liquids, by carrying out the fractionation in the presence of water and of an alkanal and, over about 3/4 of the column height, in the presence of a non-volatile or only slightly volatile acid.

Abstract: A process for the preparation of acetic acid esters CH.sub.3 --CO--O--R.sup.1 (I, R.sup.1 =an organic radical other than methyl and ethyl) by alkali-catalyzed trans-esterification of an acetic acid ester CH.sub.3 --CO--O--R.sup.2 (II, R.sup.2 =methyl or ethyl) with an alcohol R.sup.1 --OH (III), accompanied by elimination of the alcohol R.sup.2 --OH (IV), wherein(a) the trans-esterification reaction is carried out in the middle section K.sub.M of a distillation column K, the alcohol III being fed as liquid into the upper zone and the ester II into the lower zone of K.sub.M,(b) the alkaline catalyst is introduced into the upper part K.sub.U of K,(c) the alcohol IV, or a mixture of IV and the ester II, is taken off the top of the column,(d) the mixture obtained from (c) (unless the alcohol IV alone is obtained) is separated in the column section K.sub.U or in a stripper column K.sub.S into IV and the azeotrope of II and IV, and the latter is recycled to the lower zone of K.sub.