Abstract: Toluene diisocyanate is recovered from a crude distillation feed comprising less than 2% by weight of phosgene by

Abstract: The invention provides a hydrofluoric acid wastewater treatment method that achieves efficient recovery of hydrofluoric acid from hydrofluoric acid wastewater and also achieves sufficient reduction in the hydrofluoric acid concentration of the dehydrofluorinated water after treatment.

Abstract: By using a dephlegmator which conducts distillation concurrently with heat exchange within at least one distillation column, or a portion of one distillation column, of a distillation cascade, the quantity of liquid holdup within the distillation apparatus is reduced and the start-up time is shortened. Consequently, the operational costs associated with startup are reduced, and productivity is improved markedly.

Abstract: The invention relates to a method and a device for separating aluminium from chlorosilanes, in particular for separating aluminium trichloride from silicon tetrachloride or trichlorosilane or from mixtures of silicon tetrachloride or trichlorosilane. According to the invention, aluminium chloride is removed from the chlorosilanes silicon tetrachloride and trichlorosilane in a continuous process, without the addition of admixtures, to obtain a residual content of aluminium that is as low as required, by separating the aluminium trichloride and the chlorosilane by distillation, at a temperature approximately greater than 160° C.

Abstract: The invention relates to a process for recovering and producing chemicals in a pulp production process where organic chemicals, such as formic acid and acetic acid, are used as cooking chemicals. The process of the invention is based on regeneration of cooking acids and formation of additional cooking acids and furfural by evaporating the cooking liquor and then separating acetic acid, formic acid, furfural and water. The separation is preferably carried out by distillation using the furfural formed in the process as a distilling aid in the distillation.

Abstract: An improved system for reboiling a liquid in a separator is disclosed. The system includes a separator having a bottom fractionation tray, a conduit for removing liquid accumulated on the bottom fractionation tray, and a reboiler for reboiling liquid removed from the bottom fractionation tray to form a vapor which is returned to the separator by another conduit and below the spatial location of the bottom tray. The vapor returned to the separator is at least substantially sealed off from fluid flow communication with the accumulated liquid removed from the bottom fractionation tray.

Abstract: An object of the present invention is to provide a method for simulating a distillation apparatus having a coupling-type distillation column (10), the method speeding completion of simulation operation. The simulation for the distillation apparatus including a coupling-type distillation column (10) is performed by use of a simulation program for simulating a distillation apparatus including a main column (31) and a side column (32) in combination.

Abstract: A distiller (10) that employs a rotary heat exchanger (32) introduces water to be evaporated into evaporation chambers (56). During most of its operation, it collects the water that has passed through the evaporation chamber (56) without evaporating, and it reintroduces the thus-collected liquid back into the evaporation chamber, where it also adds a minor amount of unrecirculated feed liquid to make up for evaporation and concentrate removal. Simultaneously, a minor amount of feed liquid is fed into one side of a transfer pump (116). During this mode of operation, the impurities concentration in the recirculating liquid tends to increase as a result of the evaporation of pure water vapor. Periodically, the erstwhile recirculating liquid is redirected to the other side of the transfer pump (116), where it causes the feed liquid stored in the transfer pump's first side to be fed without accompanying recirculant liquid into the rotary heat exchanger's evaporation chambers.

Abstract: Process for the purification of toluenediisocyanate from a crude distillation feed comprising toluenediisocyanate, an organic solvent and less than 2% by weight phosgene by separating the crude distillation feed in a dividing-wall distillation column into at least four product fractions P1-P4.

Abstract: A distillate system, especially of the sea water, by using the sun as heat source and the sea water as cold source, falling the work pressure to the boiling point of the sea water between the temperature generated by the sun and the temperature of the sea water. The sea water and the fresh water are entered/removed to/from the distillation system at the same time, by compensating the pressure differences.

Abstract: Process for the production of a hydrofluoroalkane, according to which hydrofluoroalkane comprising organic impurities is subjected to at least two distillations.

Abstract: One or more water distillation chambers are provided wherein water containing salt or other impurities enters an upper inlet at a chamber and flows down a solar heated evaporative surface. The evaporative surface may be the interior of a pipe or the surface of a bottom sheet enclosed by a cover. In this way, the steam produced in the process will be constrained and be guided into a steam drum. The steam drum interior has cooling tubes whereby vapor entering the steam drum will be condensed into fresh water and collected for use. The cover may be heated to limit the amount of vapor condensing back into water before entering the steam drum. Multiple evaporation chambers and steam collection stages limit the distance water vapor must travel before entering a steam drum of a given stage, thereby minimizing the loss of water vapor through re-condensation before the vapor enters the steam drum.

Abstract: A distilling apparatus and method use a two step distillation and purification process for processing a waste liquid, such as an impure sulfuric acid solution, to form a highly concentrated sulfuric acid solution. First, the waste liquid is stored in a concentrating column, where it is heated. A condenser, which uses the waste liquid as a cooling medium, condenses the vapor generated by the heater. The condensed vapor is passed through a filter, which separates impurities out of the waste liquid, prior to feeding the waste liquid back into the concentrating column. Water is then removed from the waste liquid via a distilling process. The resulting concentrated liquid is then fed to a purifying column, where it is again heated, to remove residue, and condensed, resulting in a highly pure waste liquid.

Abstract: A method and apparatus for removing a contaminant from a fluid feed stream containing the contaminant. The method includes the steps of providing a feed stream and heating it in a first step to at least partially remove some of the contaminants and recover energy from a concentrate and distillate generated. Further heating the feed stream in a second heating step in a heated separator generates a saturated vapor fraction and a concentrated liquid contaminant fraction. The vapor fraction may be compressed to generate a temperature differential in the reboiler exchanger with the vapor fraction being passed into contact with a reboiler exchanger to provide a stream of condensed vapor from the reboiler. The stream may be circulated through the reboiler exchanger and the heated separator to maintain from about 1% to about 50% by mass vapor in the stream.

Abstract: This invention relates to a method for preventing (meth)acrylic acid from polymerizing during the course of distillation. The method provides for refining (meth)acrylic acid by a procedure including the steps of feeding a mixed gas obtained by catalytic gas phase oxidation of propylene and/or acrolein with a molecular oxygen-containing gas or a mixed gas obtained by catalytic gas phase oxidation of at least one compound of isobutylene, t-butyl alcohol, or methacrolein with a molecular oxygen-containing gas, to a (meth)acrylic acid collection column, collecting a (meth)acrylic acid-containing solution from the mixed gas, and feeding the (meth)acrylic acid-containing solution to a distillation column while maintaining the total concentration of aldehydes of 2-4 carbon atoms and acetone in the solution at a level of not more than 2000 ppm based on the amount of (meth)acrylic acid.

Abstract: An apparatus (10′) for extracting biomass includes an extractor (11), evaporator (12), compressor (13) and condenser (14) connected in series by pipework (17) to define a closed loop extraction circuit. A transfer line (18) selectively supplies hot solvent vapor from the outlet side of the compressor (13) to the interior of the extractor (11), where the solvent vapor heats the biomass. This causes stripping of solvent from the biomass. The transfer line (18) includes control elements (19,20) for controlling the flow of solvent vapor.

Abstract: A process of purifying titanium tetrachloride by first refluxing titanium tetrachloride (TiCl4) with copper powder, rendering the impurities of vanadium, niobium and antimony nonvolatile, and then in a single step fractionally distilling the refluxed mixture to effectively and substantially reduce any arsenic, tin, niobium and vanadium in the titanium tetrachloride.

Abstract: The invention consists of a cost-effective process and facilities for obtaining high quality drinking water and high-grade brine as a chemical raw material from raw water regardless of how much salt it contains. When combined with a thermal power-generation process, the plant also produces electric power with a fuel utilization of over 85%.

Abstract: A method for isolating 32 from a crude mixture containing HCl and an azeotropic mixture of 32 and HF is provided without the need to isolate any HF azeotrope.

Abstract: The invention disclosed herein provides methods for monitoring performance and efficiency for multi-effect evaporator systems. The invention also provides methods for monitoring the nonvolatile content of liquid products by determination of a boiling point rise. The invention involves monitoring methods that are improved over previous methods in view of their simplicity, and/or effectiveness, and/or, low cost. The methods of the invention enable system monitoring and problem diagnosis using measurements of a relatively small number of relatively easily accessible process operating parameters.

Abstract: Cyclopentane and/or cyclopentene and, if desired, isopentane can be obtained by distillative separation from a pre-benzene fraction or a C5 fraction which has in each case being partially hydrogenated to remove acetylene compounds and diolefins, wherein a) in a first fractional distillation, low boilers are removed as first top product and, either b1) the first bottom product is fed to a second fractional distillation and there cyclopentene is taken off as second top product and cyclopentane and higher-boiling hydrocarbons are taken off as second bottom product and this second bottom product is separated into cyclopentene and higher boilers in a third fractional distillation, or b2) the first bottom product is subjected to a catalytic hydrogenation and subsequently, in a fractional distillation, separated into cyclopentane as top product and higher boilers as bottom product, or b3) the first bottom product is subjected to a fractional distillation to separate off the relatively high boilers as bottom prod

Abstract: This invention provides an anti-cancer composition of high purity beta-elemene extracted from plant sources. This invention also provides for the use of the composition as well as a low cost method to prepare it by multiple passes through the precision distillation tower.

Abstract: The present invention relates to a fractionation process of the unsaponifiable material derived from black-liquor soaps of the cellulose industry. Through this procedure fractions that essentially contain free sterols, fatty alcohols, sterol esters and fatty alcohol esters respectively are separated. Fractions containing sterols or fatty alcohols can be used as such in the alimentary, cosmetic and pharmaceutical industries or they can be used as raw materials for transforming into other useful products.

Abstract: A method and apparatus for enrichment of heavy oxygen isotopes is provided wherein an oxygen starting material which contains heavy oxygen isotopes is enriched in at least one of oxygen molecule 16O17O, 16O18O, 17O17O, 17O18O and 18O18O, by means of cryogenic distillation of the oxygen starting material containing heavy oxygen isotopes. In addition, a method and apparatus are provided for further increasing the concentration of at least one of the heavy isotope oxygen molecules by means of conducting isotope scrambling on the above-mentioned plurality of oxygen molecules enriched by means of the above mentioned cryogenic distillation.

Abstract: Nitrogen trifluoride (NF3) containing less than 10 parts-per-million molar impurities, e.g., tetrafluoromethane (PFC-14), is disclosed. Azeotropic and extractive distillation processes using entraining agents for separating NF3 and PFC-14 from each other and from mixtures with other electronics industry materials are disclosed.

Abstract: A process for recovering N-vinyl-2-pyrrolidone is provided which allows to recover N-vinyl-2-pyrrolidone efficiently and steadily and in high purity by continuous distillation from a mixed liquid containing N-vinyl-2-pyrrolidone, N-(2-hydroxyethyl)-2-pyrrolidone, compounds having a higher boiling point than N-vinyl-2-pyrrolidone and water. The process includes continuously distilling the mixed liquid using a distilling column, controlling the temperature of the bottom liquid of the distilling column at 180° C. or less.

Abstract: A process for the preparation of 1,3-dichloropropane by reacting bis(3-hydroxypropyl)ether with hydrogen chloride, optionally in the presence of tertiary basic nitrogen compounds or other tertiary aliphatic bases as catalysts, distilling off the 1,3-dichloropropane and the water of reaction and working up the two phases.

Abstract: In a distillation unit (10) a rotary heat exchanger (32) receives from a radially inward position feed liquid to be purified and collects on the inner surface of a rotating exterior shell (36) liquid that has passed through its evaporation chambers (56). Stationary scoop tubes (122 and 124) scoop liquid from the resultant liquid layer that forms on the shell (36)'s inner surface, and the kinetic energy of the liquid scooped from the thus-spinning layer drives it radially inward through the scoop tubes (122 and 124) into spray arms (58) for reintroduction into the rotary heat exchanger's evaporation chambers (56).

Abstract: A distillation unit (10) includes a filter (116) through which feed water passes before it is introduced into a rotary heat exchanger (32) for evaporation and subsequent condensation. During a normal mode of operation, liquid that has not evaporated as a result of passage through the rotary heat exchanger's evaporation chambers (56) is recirculated for reintroduction into those chambers, together with a minor amount of feed liquid from the filter to make up for evaporation. At the same time, some filtered feed water is fed into one side of a transfer pump (166), where it slowly accumulates. Periodically, though, during short flushing-mode periods, the erstwhile recirculating liquid is redirected at a relatively high flow rate through the filter (116) in the reverse direction, thereby flushing it.

Abstract: A distillation unit (10) employs a rotary heat exchanger (32) forming a multiplicity of evaporation chambers (56) into which a liquid to be purified is sprayed for evaporation. Spray arms (58) spray at a steady rate into all of the evaporation chambers (56) simultaneously but not at a rate that is adequate to maintain the wetting required for efficient transfer of heat to the liquid. A scanning sprayer (140) supplements this steady spray with spray from nozzles (142 and 144) into only a few of the evaporation chambers at a time, visiting all of them cyclically. The overall rate of spray from the two sources thus combined to spray the chamber cyclically maintains proper wetting even though on average it is lower than the rate that would be required of a constant-rate spray into all of the evaporation chambers.

Abstract: A distillation unit (10) employs counterflow-heat-exchanger modules (102, 104, 106, 108, and 110) to use the heat from water that has come from a rotary heat exchanger (32) to heat feed water that is being sent to it for distillation. In one of the modules the feed water is heated only by concentrate that results from the distillation process, whereas only condensate heats the feed water in the other modules. By thus employing four different flows in two sets of heat-exchanger modules rather than three flows in a single set, the distillation unit can employ relatively simple counterflow-heat-exchanger modules and easily adjust flows to achieve a desired output concentration in response to different expected feed concentrations while maintaining optimum feed flows.

Abstract: A heat integrated distillation column provides heat at each theoretical stage of distillation in a heating portion and coolant at each theoretical stage of distillation in a cooling portion.

Abstract: A combination liquid distillation unit and heater, where the distilled liquid is heated to an elevated temperature to effect distillation, and then stored and maintained at an elevated temperature in a hot liquid tank. Thermal communication between the distillation unit portion and the storage tank allow heat from the distillation unit to be recovered in the hot distilled liquid in the tank to be transferred back to the feed water and/or to help maintain the hot distilled liquid in the tank at an appropriate elevated temperature. A start-up chamber in the distillation unit stores a reservoir of feed liquid during periods of inactivity, and allows the hot distilled liquid in the tank to preheat this feed liquid so that the feed liquid boils more quickly upon start-up.

Abstract: The present invention claims a process and an apparatus for the work-up by distillation of cleavage product mixtures produced in the cleavage of alkylaryl hydroperoxides. Usually, in the work-up by distillation of cleavage product mixtures which are produced in the cleavage of alkylaryl hydroperoxides, the cleavage product mixture is divided into three main fractions, for which at least two distillation columns are used. The use of two distillation columns has the disadvantage that the capital costs, and also the energy costs, in these conventional processes are relatively high.

Abstract: The invention relates to a novel process for removing arsenic compounds using amino/ammonium-functionalized anion exchangers from the distillation bottoms obtained in the purification of hydrogen fluoride by distillation.

Abstract: Liquid distributors collect liquid falling out of the spout group at the ends of a downcomer of a fractionation tray. The devices then distribute the liquid against the wall of the column or onto the decking of the next lower tray so to cause uniform liquid flows across the terminal decking section of the next lower multiple downcomer tray. The apparatus improves the liquid flow path on the terminal decking section of the tray, thus increasing the overall efficiency of the tray.

Abstract: A process for the separation by distillation of a mixture of 1,4-butanediol and at least one 4-hydroxybutyraldehyde, its cyclic hemiacetal and its cyclic full acetals with at least one further alcohol by carrying out the distillation in the presence of an alkaline compound. The mixture to be separated preferably contains a cyclic full acetal of 4-hydroxybutyraldehyde with a further alcohol which has a lower boiling point than butanediol and also the further alcohol in free form. The process is particularly suitable for the separation by distillation of mixtures formed in the hydrogenation of maleic acid derivatives.

Abstract: The invention relates to method for separating tocopherol from a first tocopherol admixture by heating the first tocopherol admixture composed of at least one tocopherol, a fatty acid, and an esterifying compound to esterify the fatty acid to produce a second tocopherol admixture composed of the tocopherol, the esterified fatty acid, and the unesterified fatty acid; distilling the second tocopherol admixture with the esterified fatty acid to remove the unesterified fatty acid from the second tocopherol admixture to produce a third tocopherol admixture composed of the tocopherol, with substantially removed unesterified fatty acid; distilling the third tocopherol admixture for a sufficient time and temperature to substantially remove the tocopherol from the third tocopherol admixture to produce a fourth tocopherol admixture composed of the removed tocopherol and a non-tocol component; and extracting the tocopherol from the fourth tocopherol admixture with an extraction solvent composed of a polar, organic solve

Abstract: A bifurcated fan (1) which draws in atmospheric air through air/liquid contact blocks of plastic grids which are sprayed with the liquid to be treated. The blocks change position in order to be sprayed on both front surfaces alternatively and thus remain clean. The liquid evaporates in the contact blocks and the concentrate is dehydrated in a secondary laminar evaporation base. The arrangement into converging sectors provides a geometry with minimal aerodynamic losses in a liquid with organic matter. The device includes a central tank which facilitates an aerobic biopurification process aided by the oxygenation in the contact blocks. Thermal exchanges may be included at the air inlet, using residual energy, particularly from thermal engines to which it provides refrigeration and cleaning of exhaust gases.

Abstract: An improved design of a vapor compression distiller which makes use of a rapid, highly turbulent flow through the heat-of-evaporation recovery, or primary, heat exchanger. The distiller may also include the use of turbulators to increase turbulence and mixing within the primary heat exchanger. The increased level of turbulence and mixing dramatically reduces fouling inside the primary heat exchanger and increases the heat transfer efficiency. The improvements in the distiller are maximized by recirculating the liquid to be evaporated at a high multiple of the flow rate of the liquid feed to the distiller. The distiller may also include a feed circulation loop with a secondary heat exchanger to increase the efficiency of heat-of-evaporation recovery in the evaporation/condensation cycle. Applications of the vapor compression distiller include purification of waste liquids, concentration of dilute liquid mixtures, and separation of liquid/liquid, liquid/gas, and liquid/solid mixtures.

Abstract: A process for purifying alkenyl compounds having a divalent or trivalent heteroatom in the &agr;-position relative to the double bond by distillation comprises carrying out at least two distillations in which the purified alkenyl compounds are obtained from the gas phase by condensation, where the time between the first distillation after the synthesis of the alkenyl compounds and at least one further distillation is at least one day and the purified alkenyl compounds have an APHA color number of <30.

Abstract: A method for removing a contaminant from a fluid feed stream containing the contaminant. The method includes the steps of providing a feed stream and heating it in a first step to at least partially remove some of the contaminants and recover energy from a concentrate and distillate generated. Further heating the feed stream in a second heating step in a heated separator generates a saturated vapor fraction and a concentrated liquid contaminant fraction. The vapor fraction may be compressed to generate a temperature differential in the reboiler exchanger with the vapor fraction being passed into contact with a reboiler exchanger to provide a stream of condensed vapor from the reboiler. The stream may be circulated through the reboiler exchanger and the heated separator to maintain from about 1% to about 50% by mass vapor in the stream. The apparatus includes a unique configuration of a vapor compressor, heated separator in combination with a forced circulation circuit to generate the decontamination result.

Abstract: Process for purifying acrylic acid in order to remove the polymer-type impurities in those places in the distillation columns in which they have a tendency to accumulate, and more particularly a process directed towards removing the polymeric impurities which are formed during a step for removing the aldehyde impurities from acrylic acid, according to which step the medium containing the acrylic acid to be purified is distilled by adding to this medium at least one amino compound of hydrazine type and by flushing away, at the foot of the distillation column, the heavy compounds formed by the said hydrazine-type amino compound(s) with the impurities. According to the invention, the acrylic acid to be purified is also distilled in the presence of at least one compound from the class of nonionic surface agents and of at least one polymerization inhibitor. Polysaccharide ethers and acetates, in particular ethers derived from cellulose or starch, may be mentioned as nonionic surface agents.

Abstract: A process for recovering glycols from used glycol-containing technical fluids, especially from used antifreeze comprises adding to the used glycol-containing technical fluids an organic solvent which forms with the glycol to be separated off an azeotropic mixture which has a lower boiling point than the glycol itself and distilling off this azeotropic mixture.

Abstract: A glycol regenerating system wherein a pressurized reboiler is introduced to a typical prior art system, the pressurized reboiler being in the glycol stream upstream from the conventional atmospheric reboiler. The pressurized reboiler heats the rich glycol coming from the glycol contactor from about 300° F. to 400° F. and keeps the glycol under pressure from about 10-25 psig. in order to first distill and condense VOCs (volatile organic compounds) which constitute non-condensable hydrocarbons and condensable hydrocarbons such as BTEX (Benzene, Toluene, Ethylbenzene, Xylene) compounds, the components being conveniently under pressure for transporting the components to a desired location.

Abstract: Disclosed is a process for the production and purification of dialkyl naphthalenedicarboxylate compounds wherein a crude naphthalenediacarboxylic acid is esterified with an alkanol such as methanol to produce a crude esterification product comprising dialkyl naphthalenedicarboxylate, starting materials and other compounds and the crude esterification product is purified by flash distillation to remove impurities which can cause fouling of conventional distillation equipment. A particularly useful diester is dimethyl 2,6-naphthalenedicarboxylate.

Abstract: A process for isolating trioxane from an aqueous mixture which includes trioxane, water and formaldehyde, including removing trioxane from the mixture by pervaporation, and subjecting the mixture enriched in trioxane (permeate) to rectification to give trioxane and an azeotropic mixture of trioxane, water and formaldehyde.

Abstract: Processes for the purification and color stabilization of crude maleic anhydride by distillation in a batch or continuous distillation column.

Abstract: Process and apparatus for regenerating a contaminated solvent wherein said solvent is first separated from higher-boiling contaminants in an evaporator, and then contaminants having a lower boiling point than said solvent are separated out in a condenser in which the temperature of said lower-boiling contaminants coming out of said condenser and the temperature of said solvent coming out of said condenser are separately controlled.

Abstract: A process and system are provided for the separation of a fermentation process byproduct into its constituent components and for the subsequent recovery of those constituent components. The process is remarkably simple--requiring only 1) heating of a mixture containing the byproduct so as to separate the oil from a base component of the byproduct to which the oil is bound, followed by 2) recovering the base product, oil, and possibly other substances such as molasses from the mixture. The process can be performed on a large scale and in a continuous fashion using a mechanical separator to recover fibers from a heated mixture to produce a solids stream and a liquor stream and by then removing oil and insoluble substances from the liquor stream in an evaporator assembly.