Abstract: A process for separating acetonitrile from a crude olefinically unsaturated nitrile which comprises passing a reaction gas obtained in the ammoxidation of propylene or isobutylene through a quenching column, an absorption column with water, an extractive distillation column for the olefinically unsaturated nitrile and a stripping column for acetonitrile successively, condensing the acetonitrile-containing vapor from the top of the stripping column, evaporating the condensate acetonitrile-containing liquid into a gas, subjecting the resulting gas mixture to a vapor-liquid separation and subjecting the gas separated to an incineration while withdrawing the liquid separated.

Abstract: In a distillation process, the heats of distillates and bottom product are recovered to preheat the feed and to generate the steam of higher than 5 kg/cm.sup.2 G which in turn may be utilized to improve the distillation efficiency.

Abstract: An improvement in the distillative refining of methylamines containing higher amine impurities wherein the higher amines accumulate in the distillation column, tending to cause flooding and product contamination. The improvement involves purging the column at the point the impurities concentrate, mixing the purge with water to form two phases, separating the phases and recycling the water phase for recovery of its methylamines content.

Abstract: A process for the separation of isobutane from an alkylation reaction zone hydrocarbon effluent stream comprising isobutane, n-butane, propane and alkylate is disclosed. The hydrocarbon effluent stream is charged to an isostripper column. An isobutane vapor stream from the column is condensed in indirect heat exchange with the lower liquid stream from said column comprising n-butane. The lower liquid stream is flashed in indirect heat exchange with said vapor stream at conditions to provide a vapor phase, said vapor phase being compressed and recycled to said column at a temperature to promote vapor formation therein.

Abstract: A process for purifying a crude olefinically unsaturated nitrile containing hydrogen cyanide and water by feeding the crude olefinically unsaturated nitrile at a point above the middle of a rectifying column for stripping hydrogen cyanide, withdrawing and condensing a vapor of hydrogen cyanide from the top of the column while withdrawing the olefinically unsaturated nitrile and water from the bottom of the column, which process comprises withdrawing a vapor in the column at a point between the top of the column and the point of introduction of the crude olefinically unsaturated nitrile at a substantially constant rate, cooling and condensing the vapor withdrawn in a condenser having an outlet for non-condensing gas while continuously withdrawing non-condensing gas in the vapor from the condenser, and returning the condensate liquid to the column at an intermediate point between the point of introduction of the crude olefinically unsaturated nitrile and the top of the column, and a condenser useful for the abo

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 method for purifying raw acetic acid containing formaldehyde is provided wherein raw acetic acid is heat-treated at a temperature of about its boiling point or higher, in advance of the conventional distillation for removing a lower boiling fraction, and the acetic acid thus heat-treated is distilled to remove the lower boiling fraction, whereby the content of formaldehyde can be reduced down to 30 ppm or lower.

Abstract: In recovering the multi-solvent portion of the oil solvent mixture in a solvent dewaxing process, decomposition of a thermally unstable, lower boiling solvent component is substantially avoided by recovering the solvent in a series of controlled evaporations whereby the major portion of the lower boiling solvent component is removed from the mixture prior to the removal of the remaining portion of the solvent. The solvent removal may be conducted in a high pressure evaporator having an upper section and a lower section separated by an annular tray.

Abstract: A draw rate signal generator for an atmospheric crude distillation unit receiving crude oil and providing streams 1 through 5 and a reduced crude oil includes flow rate sensors sensing the flow rates of the crude oil and of streams 1 through 4 and providing corresponding signals. Analyzers sample the crude oil and provide signals corresponding to the 35% point temperature, the API gravity and the vapor pressure of the crude oil. End point analyzers sample streams Nos. 1 and 3 and provide signals representative of the end point temperatures of streams Nos. 1 and 3, respectively. 50% point analyzers sample streams 2, 3 and 4 and provide signals corresponding to the 50% point temperatures of streams Nos. 2, 3 and 4, respectively. A circuit connected to the sensors, to the crude analyzers, to the end point analyzers and to the 50% analyzers provide signals corresponding to the draw rates for streams Nos. 1 through 5 in accordance with signals from the sensors and analyzers.

Abstract: Ethyl acetate and an excess of ethylene glycol monoethyl ether are subjected to ester-interchange reaction at a temperature not exceeding 100.degree. C. in the presence of a strongly acidic cation exchange resin as a catalyst. The resulting reaction mixture is distilled to recover the ethylene glycol monoethyl ether acetate formed. The unchanged reactants are recycled to the reaction zone for re-use, and the by-product ethanol is recovered in a highly pure form. This method can be continuously performed easily and effectively without the need to separate the catalyst or to employ complex distilling steps and without involving other difficulties.

Abstract: A control system for a multiple feed fractional distillation column is disclosed in which the flow rate signals of the multiple feed streams are delayed and combined for use in feedforward predictive control of the upper reflux flow, intermediate reflux flow and/or reboiler fluid flow to the fractional distillation column. Temperature measurements of the upper vapor stream, the upper reflux stream, the intermediate vapor stream and the intermediate reflux stream as well as analysis of a product stream can be utilized to provide feedback control of the fractional distillation column.

Abstract: An improved method for separating an ester formed in a reaction mixture is disclosed. The method comprises controlling the ratio of organic acid and alcohol utilized and the removal of unreacted alcohol as an alcohol-ester azeotrope.

Abstract: An apparatus is described for use in combination with a conventional distillation column to provide for measurement and control of reflux flow from a column intermediate fractionation stage at which a liquid side stream draw is taken. The apparatus comprises liquid receiver, flow control, and flow metering elements of particular description, and of particular relative position.

Abstract: A fractionation column is provided with a feed inlet and three product outlets, with the product outlets including an overhead vapor outlet, a bottoms liquid outlet and a side draw outlet. A plurality of vertically spaced apart vapor-liquid contact trays are mounted in the column. A generally vertical partition is positioned within the column in a central region between an upper and a lower vapor-liquid contact tray and divides the central region into first and second chambers defined by the upper and lower trays, column shell and partition. The feed inlet opens into the first chamber while the side draw outlet opens into the second chamber. First control means is provided for controlling the various inputs and outputs of the column. Second control means is also provided for measuring various constituent portions of fluid mixtures within the column.

Abstract: Purified methanol is produced by distilling a water methanol mixture in (a) a first column from which is taken a product methanol stream at an upper level, weakly aqueous methanol as a side stream and water as bottoms and (b) a second column in which that weakly aqueous methanol is separated into an overhead product stream and aqueous methanol bottoms. The first column may be preceded by a preliminary volatiles-removal column. The process is economical in heat consumption, especially when methanol vapor from the second column is heat-exchanged with the feed or bottoms of the first column.

Abstract: A method for separating a feedstock comprising hydrogen sulfide, methyl mercaptan, methanol, and water in which a sufficient amount of water is injected into the fractionating column above the feedstock inlet to water wash the organic phase, decanting water and methanol from a tray below the feedstock inlet so that the stream comprising hydrogen sulfide and a minimum of water can be removed overhead and a stream comprising methyl mercaptan and a minimum of water can be removed as bottoms.

Abstract: The separation of acrylic acid from a mixture of acrylic acid and acetic acid found in the reaction product stream obtained in the process of producing acrylic acid by the oxidation of propylene or acrolein is improved by removing a vapor sidestream from the solvent recovery column found in the process. Acetic acid is then separated from this stream without the addition of external heat.

Abstract: This invention is concerned with a continuous process for separating higher boiling, heat sensitive components from a liquid product stream. It involves a rapid evaporation of the desired product of the stream in an evaporator which minimizes residence time, such as a falling film evaporator, and feeding the vapors and the remainder of the stream to a separation column where the vaporized products rise in the column. Part of the vaporized products are removed after condensation and then recycled back to the column as a reflux. This reflux after contacting one or more trays is collected and recycled to the evaporator and mixed with the product feed being treated. The liquid remainder of the feed stream is collected at the bottom of the column. The bottom of the column can be kept at a temperature which minimizes any breakdown of the heat sensitive components present therein and, if desired, the bottoms in the column can be quickly withdrawn for treatment elsewhere or for recycling back to the process.

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 process for separating, by means of a selective solvent, a mixture of C.sub.

Abstract: Crude phenol is recovered from CHP reaction products by continuously feeding to a main column separating in its uppermost section phenol from crude acetone, this fraction being removed overhead, and in the lower section crude phenol from higher boilers, including acetophenone and carbinol, the crude phenol being removed as a sidestream fraction from the main column at a point in the column above the feed-point wherein the total concentration of acetophenone plus carbinol is less than 1,000 ppm and the higher boiling compounds being removed as a base fraction.

Abstract: Ethylene glycol esters or propylene glycol esters are recovered from their mixtures with high- and low-boiling organo-halogens by (1) distilling the mixture in a first distillation zone to form a first bottoms stream comprising the high-boiling organo-halogen impurities and a first overhead stream comprising the ethylene glycol esters or propylene glycol esters together with the low-boiling organo-halogen impurities, and (2) distilling at least a portion of the first overhead stream in a second distillation zone to form a second overhead stream containing the low-boiling organo-halogen impurities and a second bottoms stream comprising the desired ethylene glycol esters or propylene glycol esters having a substantially reduced concentration of the organo-halogen impurities.

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: Methyl tertiary butyl ether may be recovered from etherification reaction effluent by azeotropic distillation to recover methanol-ether azeotrope overhead which is water-washed to give pure ether raffinate plus ether-methanol bottoms, the latter being azeotropically distilled to yield ether-methanol overhead which is recycled to water-washing.

Abstract: Treatment of liquid waste contaminated with volatile radioactive substances under both acid and alkaline conditions in a single unit consisting of a still with connecting superposed column of spaced bubble-cap type plates. The pH of the liquid in the still is different from the pH of liquid reflux in an intermediate group of plates in the column facilitating scrubbing out of the volatile radioactive substances. An intermediate loop for circulating liquid from the bottom plate of the intermediate group to the top plate of the intermediate group at controlled pH is provided for this purpose.

Abstract: A process for the recovery of ethylene oxide containing low levels of aldehydic impurities from an impure aqueous ethylene oxide solution containing the same is provided in which the impure solution is treated in a novel multi-stage, countercurrent distillation zone for improved separation of said aldehydic impurities and recovery of an ethylene oxide-containing product stream having the desired low concentration of aldehydic impurities.

Abstract: Butadiene is recovered from a hydrocarbon fraction containing it together with butenes and acetylene hydrocarbons by introducing said fraction into a first extractive distillation column, feeding aqueous acetonitrile into said column above the introduction point of said fraction and extracting a vapor stream containing butadiene below said introduction point; feeding said vapor stream into a second extractive distillation column, feeding aqueous acetonitrile above the introduction point of said vapor stream and recovering a vapor stream consisting essentially of butadiene at the top of said second column; and rectifying this last vapor stream to recover pure butadiene.

Abstract: Anhydrous liquid sulfur dioxide is recovered from environmentally unsuitable vapor or liquid streams comprising water, sulfur dioxide and carbon dioxide. The vapor streams are fed into an absorption zone and contacted with a lean liquid water stream. A resulting sulfur dioxide rich water stream is passed into a first fractionation column utilized in part as the stripper column which produces the lean water stream. A sidecut stream removed above the feed point is passed into a second fractionation column, and the overhead vapor of the first column is subjected to two stages of partial condensation to aid carbon dioxide rejection. Anhydrous sulfur dioxide is removed as a liquid sidecut of the second column, and the net overhead vapor of the second column is preferably passed into the overhead system of the first column after a partial condensation.

Abstract: A process for the purification of crude acetic anhydride by continuous fractional distillation, which comprises first introducing the anhydride into an evaporator, thereafter removing from the evaporator the non-distillable components contained in the crude anhydride, then introducing the distillable components of the anhydride in vapor form into about the central section of a fractionating column, withdrawing from the top of the column the low boiling components together with acetic acid, withdrawing near the bottom of the column a high-percentage of pure acetic anhydride, and separating from the sump of the column up to about 8% by weight based on the initial amount of crude acetic anhydride and returning the same to the evaporator.

Abstract: A process is provided for producing ultra-pure propionic acid, i.e., acid containing less than 20 parts by weight of iodine per billion parts by weight of acid, wherein crude acid containing water and iodine contaminants is distilled in a single distillation zone and no waste streams requiring treatment or disposal are obtained.

Abstract: A process is provided for purification and drying of acetic acid containing water and methyl iodide and hydrogen iodide as contaminants. The process comprises distillation in a two-zone system wherein the major part of the methyl iodide and hydrogen iodide and some water are removed as overhead and bottoms, respectively, from the first zone; a stream from the middle section of the first zone is introduced into a second zone into which there is also introduced a stream of methanol; and a stream of dry purified acid is recovered from the bottom of said second zone. The process provides both for the recovery of the iodine components and the methanol added for re-use in production of additional acetic acid by the reaction of methanol and/or methyl acetate with carbon monoxide in contact with a catalyst system formed on mixing of a rhodium or iridium component and an iodine component in the presence of carbon monoxide.

Abstract: In a fractional distillation process and apparatus two columns are intercoupled to provide variable reboil in one and variable reflux in the other so as to approach closely to thermodynamically ideal fractionation. The variable reboil column has a series of heat transfer assemblies at different levels up its height and these are fed with vapor withdrawn from respective different levels of the variable reflux column. Partial condensation of each withdrawn stream takes place in the respective heat transfer assembly, after which the partially condensed stream is returned to the variable reflux column at a level close to the level at which the corresponding vapor was withdrawn. The variable reflux column will ordinarily be at a higher pressure, and mounted at a lower level than the variable reboil column.

Abstract: Heat balance of a fractionation column is maintained through the utilization of differential temperature sensors located at selected points in the height of the column. Signals representative of three delta-T's are employed in regulating the quantity of reflux to the rectification zone and the enthalpy (heat-input content) of the reboiled liquid bottoms stream. With respect to the former, two differential-temperature signals are used; these result from four temperature sensors vertically-spaced along virtually the entire height of the fractionation column.

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 method is provided for removal of excess water which tends to build up in recycle streams and reduces the rate of pure acid production during operation of a distillation system for purification of crude acetic acid containing water and methyl iodide. The crude acid is introduced into the upper half of a distillation zone. The methyl iodide, a major proportion of water and an equivalent amount of acid are removed overhead from the zone. A minor proportion of the water containing a small amount of acetic acid is removed as a liquid sidedraw at a point near the top of the distillation zone. A product acid stream essentially dry and substantially free of methyl iodide is removed from the bottom of the distillation zone. The overhead stream can be stored, disposed of or preferably recycled to the acid-producing step. The liquid water sidedraw may either be discarded or subjected to rectification for recovery of acid values.

Abstract: Insertion of about one-half of a small diameter distillation column through the bottom of a larger diameter column permits the fractionation of a feed stream fed to the small column into three distinct high purity streams within one vessel. An annular space between the two columns functions as a stripping section which produces a pure stream of intermediate boiling range material. Open communication between the columns at the top of the small column eliminates the requirement of having a separate reflux system for the small column.