Abstract: A process for the continuous isolation of phthalic anhydride and maleic anhydride from the reaction gases obtained by catalytic oxidation of o-xylene or naphthalene with air, wherein the reaction gases are treated with a hydrocarbon of boiling range from 115.degree. to 175.degree. C. as the solvent in a column, and are then treated with an organic solvent of boiling range from 180.degree. to 290.degree. C. in a second column, the phthalic anhydride and maleic anhydride being isolated from the liquid bottom product of the first column.

Abstract: A metal-refining process and a corresponding system characterized by being adapted to minimize the health hazard by appropriate purification of the gases or vapor products resulting from acid action on a metal compound. This metal refining features the use of vacuum at a downstream point to regulate the admixing of air with the vapor products in the effluent and to draw activating air in the mixture of acid and metal compound at the upstream point. This refining system includes gas outlet manifolds constructed and arranged to enhance the purification of the vapor products by comminuting the vapor products into small bubbles upwardly through a water tank. Each manifold consists of a casing having a plurality of small gas outlet apertures each communicating with a small tube which extends within the casing and has a bevelled end for self-cleaning of the tube. These tubes prevent clogging of the apertures by solid particles in the gas flowing through the casing.

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 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 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: A continuous fractionation technique is provided for recovering ethylene from an olefinic feedstock comprising C.sub.3.sup.+ higher olefins. This technique provides methods and means for contacting the olefinic feedstock in a counter current sorption tower with a liquid sorbent stream comprising C.sub.6.sup.+ gasoline range hydrocarbons under process conditions to selectively sorb substantially the entire C.sub.3.sup.+ olefin components from the feedstock, withdrawing an ethylene-rich vapor stream from the sorption tower and further contacting the ethylene-rich stream with a distillate range liquid hydrocarbon stream in a sponge absorber to purify the ethylene stream. Typically, the olefinic feedstock consists essentially of volatile hydrocarbons, and preferably comprises about 10 to 50 mole % ethylene and 10 to 50 mole % propene. Purified ethylene product may be recovered having an average molecular weight not greater than 28.5 under non-cryogenic conditions.

Abstract: A process for the separation of diisopropylether from a hydrocarbon stream containing it, by contacting the stream with ethylene glycol whereby the diisopropylether is absorbed by the glycol and a purified hydrocarbon stream is separated therefrom.

Abstract: Ethylene oxide is recovered from aqueous solutions by extracting with carbon dioxide in the near-critical or super-critical state, thereby selectively removing the ethylene oxide from water, and thereafter recovering ethylene oxide from the carbon dioxide by distillation or other suitable means.

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: This invention relates to an improved process for reducing solute in a vapor stream and, particularly, to the adaption of this process in concentrating solutions in an evaporator wherein the solution is heated to volatilize solvent. The improvement for reducing solute in the vapor stream resides in (a) the utilization of a wire mesh mist eliminator pad having a wire diameter of from 0.001-0.05 inches, an interfacial area from 50-200 ft.sup.2 /ft.sup.3, a void space of about 90-99 percent and a packing thickness of 4-16 inches and (b) spraying a liquid through the mist eliminator pad, the liquid being sprayed uniformly over the surface of the mist eliminator pad at a rate of 0.6-2.5 pounds liquid per pound of vapor to provide a wetting rate of 0.1-0.25 gallons per minute per square foot of mist eliminator surface area. The process has been particularly advantageous in the multistage concentration of corrosive products particularly in the concentration of a 60-70% sulfuric acid solution to about 93 percent.

Abstract: The invention provides a means for reducing the energy consumed by thermally activated separation processes such as fractional distillation. This is done by recovering at least part of the reject heat from such processes and upgrading it for recycle back to input heat. The upgrading is accomplished by another low temperature source of heat which may also be the separation process reject heat. A simple and reliable heat pump using the reverse absorption principle is incorporated in the separation process to accomplish this upgrading.

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: A method and apparatus for distilling readily polymerizable liquid such as readily polymerizable monomers without causing the formation of an undesirable polymerization product is disclosed. This distillation is effected by(a) vaporizing the polymerizable liquid from a liquid phase containing the same in an evaporator by externally heating the liquid phase;(b) converting the vapor of the polymerizable liquid to a superheated state by externally heating, and introducing the vapor of the polymerizable liquid to the inlet of a condenser, while the vapor is maintained at the superheated state; and, then,(c) condensing the vapor in the condenser, while a portion of the condensed fraction is circulated to the inlet of the condenser, whereby the condensation surface thereof is wetted.

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: 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: To obtain a cyanogen chloride which is practically free from water and preferably also free from hydrogen cyanide, hydrogen chloride and organic compounds, the crude cyanogen chloride is fractionally distilled. The return is led in countercurrent flow to the crude gas, thereby takes up the impurities and is further evaporated in the lower portion of the column, respectively in a special apparatus, by a liquid whose temperature is higher than the boiling temperature of cyanogen chloride. Thereby this liquid also takes up the impurities. The purification action is aided by a wash for the crude cyanogen chloride connected in series before it enters the fractionating column. It is very advantageous to combine the process with a plant for the production of cyanogen chloride.

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 normally liquid hydrocarbon having a minimum boiling point of about 425.degree. F. is utilized to provide the liquid seal in a vacuum pump which intakes a gaseous light ends stream resulting from a process for the production of ethyl acrylate by the reaction of ethylene with acrylic acid in the presence of a sulfuric acid catalyst. Upon contact in the vacuum pump, the gaseous light ends are partially absorbed into the normally liquid hydrocarbon, with the normally liquid hydrocarbon being recovered by fractionation.

Abstract: Process for producing and isolating methyl-tert-butyl ether (MTBE) comprising etherifying isobutene, contained in a C.sub.4 hydrocarbons mixture, with methanol in the presence of a recycle stream of C.sub.5 and/or C.sub.6 hydrocarbons, separating from the obtained reaction product, by fractionation, at least the major part of the unconverted C.sub.4 hydrocarbons, and discharging them, and fractionating the remaining product in two fractions, one of which contains an azeotrope of methanol with the C.sub.5 and/or C.sub.6 hydrocarbons and is recycled, the other fraction containing the purified MTBE.

Abstract: A process for recovering pure benzene from hydrocarbon mixtures containing the same and non-aromatic compounds which are gaseous and difficultly condensible is described in which the feedstock is fed to an initial distillation column operated at atmospheric or sub-atmospheric pressure. Overhead comprising benzene and non-aromatics is obtained and a portion thereof condensed. The condensible material is in part returned to the distillation column and in part subjected to extractive distillation to recover pure benzene. Those components which did not condense, i.e. the non-condensible and difficultly condensible components and entrained aromatics are fed to a reflux vessel such as a scrubber, stripper, or the like for recovery of any benzene or other valuable components which might be soluble in a selective solvent and used for such recovery. The selective solvent can be the same solvent used for the extractive distillation.

Abstract: The thermal efficiency of an ammonia still is significantly increased by the use, in conjunction with the usual countercurrent steam stripping medium, of an auxiliary inert gas stripping medium initially heated and humidified by passage through a heat exchanger together with hot still bottoms derived from the still.

Abstract: Gases resulting from the re-processing of spent nuclear fuel contain radioactive substances which are separated by mixing the said gases with a carrier gas having approximately the same separating behavior as the radioactive substances; the gas mixture obtained is separated into a fraction containing the radioactive substances and the carrier gas and a fraction free from these components. In a further stage the radioactive substances are separated from the carrier gas.

Abstract: A method for purifying acrylonitrile resulting in capital and operating cost savings consists of distilling a solution of acrylonitrile and impurities in a distillation column under vacuum, and removing the purified acrylonitrile as a vaporous sidestream from the column.

Abstract: A single-step process is disclosed for purifying raw cyanogen chloride gas contaminated with chlorine by fractionally separating chlorine from cyanogen chloride and thereafter absorbing essentially chlorine-free cyanogen chloride in a solvent.

Abstract: Organic material having a normal boiling point in excess of 200.degree. C. and a relative volatility with respect to water of at least one is removed from water contaminated therewith. The process comprises passing a current of vapor, sufficient to vaporize at least a portion of the organic material, through a moving stream of the contaminated water. In a preferred embodiment, the process comprises adjusting the pH of the contaminated water to a level sufficient to prevent substantial dissociation of the organic material. The contaminated water is then countercurrently contacted with a sufficient vapor flow to vaporize at least a portion of the organic material. The resulting organic material-containing vapor can be recovered, and the organic material removed. Illustrative of the process is the removal by air stripping of pentachlorophenol from waste water contaminated with about 250 parts per billion thereof.

Abstract: C.sub.2 -C.sub.6 monocarboxylic and dicarboxylic acids are scrubbed from gas phase mixtures of such acids and water by gas absorption techniques utilizing a liquid solvent comprising a polyoxyalkylene glycol or a monoalkyl or dialkyl ether thereof. The solvent enriched with the acid is subjected to distillation to recover a substantially anhydrous acid product.

Abstract: In a process for preparing diacetoxybutene by subjecting butadiene, acetic acid and oxygen to reaction, the discharge gas from the reaction system or purification system, containing butadiene and/or acetic acid, is treated by contacting with diacetoxybutene and/or diacetoxybutane (absorbent) to allow butadiene and/or acetic acid to be absorbed by said absorbent. A part of the diacetoxybutene separated in a distillation tower from the reaction product solution containing diacetoxybutene produced by said three-component reaction can be used as said absorbent. In this case, butadiene and/or acetic acid can be recovered from said discharge gas by supplying the absorption solution into said distillation tower. Also usable as said absorbent is diacetoxybutane obtained by hydrogenation of diacetoxybutene.

Abstract: A process and installation for the treatment of distillate water recovered by flash evaporation from impure water, such as sea water, in which gases desorbed during the flash evaporation, including carbon dioxide, are recovered and intermixed with the distillate water prior to and inside an absorber so that the carbon dioxide is absorbed by distillate water to thereby improve the property of the distillate water for human consumption.

Abstract: Recovery of substantially pure water for reuse from waste feed solutions, saline solutions, etc. is carried out at considerably lower capital and/or operating costs using a modified absorption cycle. The process is carried out under vacuum so that relatively low temperature heat sources can be used to evaporate water as well as high temperature sources. The system comprises an evaporator, an absorber, a generator and condenser. A portion of the feed solution entering the evaporator vaporizes due to its latent heat and the vacuum of the system. The water vapor product is absorbed by an absorbent in the absorber. The absorbent solution is transferred to a higher pressure zone in the generator where the water held by the absorbent is vaporized. This vaporized water is condensed for recovery. A heat transfer medium is applied to each stage to either apply or remove heat as appropriate.

Abstract: A process for reducing the chemical oxygen demand of water removed from a mixture of crude tetrahydrofuran and water, said process comprising contacting said mixture in the vapor phase with a dilute sodium hydroxide solution, then optionally contacting the tetrahydrofuran-water mixture after condensation with a concentrated sodium hydroxide solution and separating water from the thus treated mixture, said water having reduced chemical oxygen demand over water that is removed from said mixture merely by distillation.

Abstract: Steam carrying fatty acids is contacted in a barometric condenser with a cooling medium comprising a fatty acid having between six and eighteen carbon atoms to produce a liquid organic phase containing the fatty acids which were entrained in the steam, and an aqueous phase, such phases being readily separated by decantation. After separation of the phases, a portion of the organic phase is used for the cooling medium.

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 method for separating two liquid components from a mixture by distilling the mixture in the presence of a third liquid which is immiscible at least with the component having the higher boiling point with the third liquid having a boiling range from at least the boiling point of the lower boiling component up to the boiling point of the higher boiling component. In a preferred embodiment the liquid mixture components are glycol and water and the third liquid is a naphtha fraction having a boiling range from about 212.degree. F. (100.degree. C.) to about 410.degree. F. (210.degree. C.).

Abstract: Acrolein and other light ends are removed from the effluent of a process for the production of acrylic acid by the vapor phase catalytic oxidation of acrolein or an acrolein precursor, such as propylene, by passing the effluent to the base of a fractionation tower and contacting such with the descending stream of liquid within the tower so as to partially condense the condensibles in the effluent, a portion of the liquid bottoms being recycled to the upper portions of the tower and a portion withdrawn as crude acrylic acid product. Acrolein is removed overhead.

Abstract: Impurities such as hydrogen sulfide and carbon dioxide are removed from fluids such as natural gas, synthesis gas or liquid or gaseous hydrocarbons by contact with an aqueous alkanolamine solution which absorbs said impurities from the fluid. The resultant spent impurity-enriched absorbent amine stream containing the absorbed impurities is split into two streams; one stream being routed directly to the top of an amine regenerator column and the second stream being routed to a heat exchanger where it is heated en route to an intermediate point of the regenerator column by heat exchange with the hot regenerated solution coming from the bottom of the regenerator column. The spent amine stream which is passed without prior heating directly to the top of the regenerator column is heated by condensing steam in the column which would normally escape therefrom, thereby reducing the amount of "saturation" steam which is lost from the system.

Abstract: In an oxidation process for converting methacrolein to methacrylic acid, methacrylic acid is recovered by cooling and condensing the effluent from the oxidation, followed by azeotropic distillation of the condensate with a suitable solvent, such as methyl n-propyl ketone. The condensed effluent contains methacrylic acid and water as the major components along with by-product acetic acid, a minor amount of unreacted methacrolein and impurities. Substantially dry crude methacrylic acid is separated as a bottom product from the azeotropic distillation and an azeotrope of water and the solvent is taken overhead and condensed. After condensation, solvent-rich and water-rich phases form and are separated. The solvent-rich phase is returned to the distillation column as a reflux, while the water-rich phase is sent to a stripping column for recovery of residual solvent. Water is withdrawn from the bottom of the stripping column and recycled or discarded, as desired.

Abstract: Terephthalonitrile is separated from p-xylene containing solution by fractional distillation in the presence of p-tolunitrile, with the p-tolunitrile being present in the fractional distillation tower in an amount sufficient to solubilize the terephthalonitrile in all portions of the column at which the temperature in the column is below the melting point of tetephthalontrile, whereby terephthalonitrile can be recovered as a liquid. The solution generally includes p-xylene, benzonitrile, p-tolunitrile and terephthalonitrile and is separated from a terephthalonitrile production reaction effluent by direct contact quenching with an organic liquid containing p-tolunitrile.

Abstract: In the oxidation of propylene and/or acrolein, high-boiling or non-volatile byproducts are separated from the solvents used for absorbing the acrylic acid by treating the said solvents laden with byproducts with the hot reaction gases in such amounts that the major portion of the solvents evaporates, the residual solvent containing a high percentage of said byproducts then being discarded or worked up.

Abstract: A recovery and purification operation in which a perfluorocarboxylic acid fluoride, e.g., trifluoroacetylfluoride, is recovered having a high purity from an electrochemical cell fluorination operation is described. The effluent is compressed and chilled, separation of vapor from liquid phases is effected to produce a liquid which is further chilled and subcooled and employed as absorption medium in an absorption zone. Vapors separated are compressed and chilled and subjected to a further phase separation, vapors from which are passed to the absorption zone. The enriched absorption medium together with liquid from the second phase separation is passed to a fractionation zone for recovery of the perfluorocarboxylic acid fluoride from incompletely fluorinated compounds which can be returned to the cell for further fluorination.The invention is applicable to the recovery of perfluorocarboxylic acid fluorides of mono- and dicarboxylic acids containing from 2 to about 10 carbon atoms.

Abstract: Gaseous and/or vaporous monomers are recovered from reaction off-gases by treating the latter with compounds which are liquid at 50.degree. C and atmospheric pressure and with which, and/or in which, the said monomers are subsequently reacted.

Abstract: In dual temperature systems utilizing different fluid materials in liquid and gas phases separable from each other (for example H.sub.2 O and H.sub.2 S), the phases are contacted with each other at a relatively hot temperature. Herein combinations of method and means are provided by which the gas is conditioned by raising its temperature and humidity principally by heat derived from the cooling and dehumidification of said gas. Special provisions are made in the combinations for transferring said heat and for the conditioning of the gas with high efficiency; and for economically controlling the temperature of the condensate resulting from the dehumidification of the gas to adapt it for particular uses in the system. Method and means are provided for such liquid gas contacting systems for efficiently stripping or separating dissolved gas from the effluent liquid and returning one of the so separated materials to the system.

Abstract: A process and apparatus for the regeneration of washing oil which has been spent to recover naphthalene and/or benzol from coke oven gas. The spent washing oil is stripped by steam in a bubble column arranged as an integral part of a single main column that includes first, second and third exchange column sections disposed in a superimposed relation one above the other to receive the stripped vapors from the bubble column. The first exchange column section is fed with a mixture of toluene, xylene and naphthalene as a reflux, the second exchange column section is fed with water as the reflux and the third exchange column section is fed with benzol as the reflux. The head product from the column is condensed and passed through a first-phase separator to obtain a substantially anhydrous benzol fraction and a water fraction. These fractions are separately used as a reflux for the second and third exchange column sections.

Abstract: An overall process for the separation of ethyl fluoride from a propane stream containing same is provided wherein said propane stream is extractively distilled using HF, as the extractive solvent producing a first mixture consisting essentially of propane and HF and a second mixture consisting essentially of ethylfluoride and HF, and wherein this second mixture is then mixed with water followed by phase separation.

Abstract: Apparatus for separating hydrocarbons from flue gas and the like, including a gas scrubber, a collecting container supplying the scrubber with wash oil, and a vacuum distillation container receiving wash oil discharged from the scrubber.

Abstract: A process for the purification of partially fluorinated dimethyl ethers to remove impurities from bis(difluoromethyl) ether and from difluoromethyl fluoromethyl ether by washing the ether-containing stream with sulfuric acid or hydrochloric acid. The acid extract is diluted with water to form two phases which can be separated.

Abstract: A process for obtaining isobutylene in a purity greater than 99.5% from an initial feed of relatively pure isobutylene which further has minor quantities of tertiary butyl alcohol, water, polymers of isobutylene, and cis and trans-2-butenes in an economic manner while retaining good yields of the isobutylene by distilling the initial feed to separate a significant portion of the isobutylene with a purity equal to or greater than 99.

Abstract: A low boiling water immiscible fluid containing two or more molecular species and having a variable boiling point is contacted in the liquid state with relatively hot or warm water such as surface sea water or geothermal water, thereby generating vapor of immiscible fluid (together with a certain amount of water vapor) which is used to drive a prime mover such as a gas turbine and thereby produce mechanical energy; the exhaust vapor from the prime mover is condensed by direct contact with a relatively cool or cold liquid aqueous phase such as deep sea water or water from a lake or stream or cooling tower to condense the vapor; and the condensate is recycled. Provision is made for ridding water discharged from the system of entrained and dissolved immiscible fluid. By countercurrent flow of the liquid phases and by suitable matching techniques greater efficiency is obtained. The invention is also applicable to heat pumps.

Abstract: Process for the recovery of phthalic anhydride in which gases as obtained in the catalytic atmospheric oxidation of o-xylene or naphthalene are treated with a hydrocarbon containing C.sub.26.sub.- paraffins, cooling, if necessary, the hydrocarbon laden with phthalic anhydride, separating the solid phthalic anhydride followed by melting and distillation thereof.

Abstract: Water vapor generated in concentrating an aqueous urea solution and containing a small amount of aqueous urea solution mist, ammonia and carbon dioxide is treated to recover urea and ammonia values. The water vapor is introduced into a separator wherein all of the urea solution mist is separated together with a part of the ammonia and the carbon dioxide to form a first condensate. The water vapor is then fed into a surface cooler wherein the water vapor is indirectly cooled to form a second condensate. The first condensate is used for process water and the second condensate is subjected to rectification to separate ammonia and carbon dioxide contained therein in the form of a mixed gas, which is recovered, from the remaining waste water free of ammonia and carbon dioxide.