Abstract: A process for purifying propylene oxide characterized by subjecting a liquid reaction mixture containing propylene oxide, and water, hydrocarbons and oxygen-containing organic compounds as impurities obtained by reacting cumene hydroperoxide with propylene to extractive distillation using an extractant of a hydrocarbon having 7 to 20 carbon atoms with an extractive distillation column, and controlling a concentration of propylene glycol in the extractant supplied to the extractive distillation column to 20% by weight or less.

Abstract: A method for collecting acrylic acid is provided, which includes the step of collecting acrylic acid using an aqueous medium from a reaction gas containing acrylic acid obtained by catalytic vapor-phase oxidation of propane, propylene, and/or acrolein, the step being conducted so as to satisfy the following formula (1) (B/A)<1.25 (1) wherein A represents a weight fraction of acrylic acid to all condensable ingredients in the reaction gas before collecting acrylic acid and B represents a weight fraction of acrylic acid in bottoms of a collection device used in the step of collecting. According to the method, acrylic acid can be efficiently collected from the reaction gas containing acrylic acid obtained by catalytic vapor-phase oxidation.

Abstract: A liquid phase process is disclosed for producing halogenated alkane adducts of the formula CAR1R2CBR3R4 (where A, B, R1, R2, R3, and R4 are as defined in the specification) which involves contacting a corresponding halogenated alkane, AB, with a corresponding olefin, CR1R2?CR3R4 in a dinitrile or cyclic carbonate ester solvent which divides the reaction mixture into two liquid phases and in the presence of a catalyst system containing (i) at least one catalyst selected from monovalent and divalent copper; and optionally (ii) a promoter selected from aromatic or aliphatic heterocyclic compounds which contain at least one carbon-nitrogen double bond in the heterocyclic ring. When hydrochlorofluorocarbons are formed, the chlorine content may be reduced by reacting the hydrochlorofluorocarbons with HF. New compounds disclosed include CF3CF2CCl2CH2CCl3, CF3CCl2CH2CH2Cl and CF3CCl2CH2CHClF. These compounds are useful as intermediates for producing hydrofluorocarbons.

Abstract: A method for separating difluoromethane from a mixture of difluoromethane and at least one impurity, the method involving extractively distilling the mixture using dichloromethane as an extractive agent to recover a product stream of purified difluoromethane having a concentration of impurity lower than that of the mixture.

Abstract: A process is proposed for the separation of C5+ cuts by distillation into a low-boiler (A), a medium-boiler (B) and a high-boiler fraction (C) in one or more dividing-wall columns (TK), in which a dividing wall (T) is arranged in the longitudinal direction of the column with formation of an upper, common column region (1), a lower, common column region (6), a feed part (2, 4) with rectifying section (2) and stripping section (4), and a withdrawal part (3, 5) with rectifying section (5) and stripping section (3), with feed of the C5+ cut (A, B, C) into the central region of the feed part (2, 4), discharge of the high-boiler fraction (C) from the bottom of the column, discharge of the low-boiler fraction (A) via the top of the column, and discharge of the medium-boiler fraction (B) from the central region of the withdrawal part (3, 5), wherein the dividing ratio of the liquid reflux at the upper end of the dividing wall (T) is set in such a way that the proportion of high-boiling key components in the liquid re

Abstract: The present invention relates to a process for separating 2-butanol from tert-butanol/water by adding of tert-butanol such that the water concentration lowers to less than the limit concentration of the distillation boundary line connecting the two azeotropes TBA/water and SBA/water and is subsequently worked up by distillation.

Abstract: The invention relates to a process for separating 2-butanol from an industrial mixture which includes 2-butanol, tert-butanol and water by separating water from the industrial mixture by distillation to obtain a distillate, wherein the distillate has, in terms of the 2-butanol, tert-butanol and water in the industrial mixture, a proportion by mass of water, which at a pressure, is greater than the limit concentration of the distillation boundary line connecting an azeotrope of tert-butanol and water; and an azeotrope of 2-butanol and water; subsequently changing the pressure so that the mixture has, in terms of the 2-butanol, tert-butanol and water in the distillate, a proportion by mass of water which is less than the limit concentration of the distillation boundary line connecting the distillation boundary line connecting an azeotrope of tert-butanol and water; and an azeotrope of 2-butanol and water; and subsequently distilling the mixture at the same pressure into a stream comprising 2-butanol and a strea

Abstract: The present invention provides an industrially easy and economical method for purification of acrylic acid which enables to efficiently eliminate impurities from a crude acrylic acid containing aldehydes as the impurities while the formation of acrylic acid polymer is inhibited. The method for purification of acrylic acid includes the step of distilling a crude acrylic acid which is charged with an aldehyde treatment chemical, wherein the concentration ratio of furfural to acrolein by weight in the crude acrylic acid is adjusted so as to satisfy the following equation: (furfural concentration by weight)/(acrolein concentration by weight)?100.

Abstract: There is disclosed a method and apparatus for treating produced water from a heavy oil thermal recovery unit to achieve water recovery and recycle levels of greater than 80% and as high as 100% to achieve zero discharge criteria. The method includes the initial steps of capturing the waste heat energy from the high pressure steam separator located downstream of the steam generators. Further, transferring the heat energy into a heated separator and reboiler exchanger to distill oil reservoir produced water and recover distilled water and a concentrated brine or solid product. The heated separator concentrated stream is circulated through the reboiler exchanger to maintain from 1% to about 50% mass vapour in the stream returning to the heated separator and prevent fouling and scaling. The apparatus includes a low pressure waste energy separator, heated separator and vapour compressor in combination with a forced circulation circuit to generate the distilled water.

Abstract: A process for the separation of diisobutylene from tertiary butyl alcohol utilizing pressure swing azeotropic distillation to achieve the desired separation. The pressure swing azeotropic distillation takes advantage of the fact that different azeotropes are formed at different pressures. Isobutylene in C4 streams is oligomerized in the presence of tertiary butyl alcohol to produce the diisobutylene. Tertiary butyl alcohol is present in the dimerization because it improves the selectivity to the dimer (diisobutylene) by suppressing further reaction to the trimer or higher. The diisobutylene is separated from the tertiary butyl alcohol utilizing two distillation columns. The first distillation is operated at a higher pressure than the second such that the minimum boiling azeotropes of tertiary butyl alcohol and diisobutylene have different concentrations of tertiary butyl alcohol. Diisobutylene is removed as bottoms from the first distillation column and unreacted C4's are removed as overheads at 60-130 psig.

Abstract: There is provided an azeotropic mixture having 1,1,1,3,3-pentafluoropropane and hydrogen fluoride. Further, there is provided a process of separating/purifying R-245fa and/or HF from a mixture of R-245fa and HF wherein the mixture of 1,1,1,3,3-pentafluoropropane and hydrogen fluoride is subjected to a distillation step so that a distillate is obtained which has the azeotropic mixture of 1,1,1,3,3-pentafluoropropane and hydrogen fluoride, and a bottom product is obtained which has separated/purified 1,1,1,3,3-pentafluoropropane or hydrogen fluoride.

Abstract: This invention provides a concentrator capable of drawing out a concentrate of a constant concentration. The concentrator includes a heater having a heating medium that has been heated to a temperature not less than the boiling point of a solution fed to the concentrator—whereby said heater heats the solution to evaporate the solvent to a vapor to make a mixture of the vapor and a liquid—and a gas-liquid separator for dividing the mixture into the liquid and the vapor. The concentrator provides for returning the liquid separated in the gas-liquid separator to the heater, for drawing out a portion of the liquid separated in the gas-liquid separator, for detecting the concentration of an intended component in the drawn out liquid, and for controlling the liquid draw-out so that when the concentration is above a predetermined threshold, liquid draw-out commences, and when the concentration is below the threshold, liquid draw-out stops.

Abstract: A process for preventing undesired polymerization is conducted by maintaining an effective concentration of a stabilizer which comprises N-oxyl radicals in a mixture containing ethylenically unsaturated compounds, wherein (i) an electronic signal which correlates with the concentration of the N-oxyl radicals in the mixture is obtained periodically or continuously, (ii) the electronic signal is compared with a reference value, and (iii) addition of a stabilizer to the mixture is controlled according to the comparison (ii). The signal is preferably obtained by ESR measurement. The process permits efficient use of the stabilizer.

Abstract: A method of purifying 2,6-dimethylphenol to remove the odorous impurities includes distilling a crude mixture to yield a first light fraction enriched in 2,6-dimethylphenol, and a first heavy fraction enriched in 2,4,6-trimethylanisole, and distilling the first light fraction to yield a second light fraction, and a second heavy fraction enriched in 2,6-dimethylphenol. The concentration of 2,4,6-trimethylanisole in the second heavy fraction is less than 50% of the concentration of 2,4,6-trimethylanisole in the mixture. The purified 2,6-dimethylphenol is useful for preparing low-odor poly(arylene ether) resins.

Abstract: The present invention relates to a process for separating 2-butanol from tert-butanol/water by adding of tert-butanol such that the water concentration lowers to less than the limit concentration of the distillation boundary line connecting the two azeotropes TBA/water and SBA/water and is subsequently worked up by distillation.

Abstract: A method for collecting acrylic acid comprising the step of collecting acrylic acid using an aqueous medium from a reaction gas comprising acrylic acid obtained by catalytic vapor-phase oxidation of propane, propylene, and/or acrolein, the step being conducted so as to satisfy the following formula (1) wherein A represents a weight fraction of acrylic acid to all condensable ingredients in the reaction gas before collecting acrylic acid and B represents a weight fraction of acrylic acid in bottoms of a collection device used in the step of collecting. According to the method, acrylic acid can be efficiently collected from the reaction gas comprising acrylic acid obtained by catalytic vapor-phase oxidation.

Abstract: The present invention relates to a process for separating secondary butanol (also referred to as 2-butanol or SBA below) from tert-butanol/water mixtures which are obtained in the dissociation of tert-butanol (TBA), in particular tert-butanol prepared from industrial C4-hydrocarbon mixtures, into isobutene and water.

Abstract: A process for working up by distillation the crude products obtained in the process according to DE-A 196 07 954 and containing 1,6-hexanediol (HDO), 1,5-pentanediol (PDO) or caprolactone (CLO) in order to obtain the corresponding pure products, the working-up by distillation being carried out in each case in a dividing wall column (TK) in which a dividing wall (T) is arranged in the longitudinal direction of the column with formation of an upper common column region (1), a lower common column region (6), a feed section (2, 4) having a rectification section (2) and stripping section (4), and a take-off section (3, 5) having a stripping section (3) and rectification section (5), with feeding of the respective crude product HDO, PLO or CLO in the middle region of the feed section (2, 4) and removal of the high boiler fraction (C) from the bottom of the column, of the low boiler fraction (A) via the top of the column and of the medium boiler fraction (B) from the middle region of the take-off section (3, 5), or

Abstract: This invention relates to a continuous process and an apparatus (1) for removing dissolved and undissolved solids and/or high boiling point liquid contaminants from a mixture of miscible liquids (9). A recycle liquor stream (6) is fed at high velocity through a heat exchanger having a single flow path (12) and the heat added by the heat exchanger is sufficient to vaporize the feed stream (2) when the recycle liquor and feed stream are mixed upon delivery to the separation vessel (3).

Abstract: A method for starting up a distilling column destined to handle an easily polymerizing compound-containing solution characterized by supplying at the start of the operation of the distilling column a polymerization inhibitor to the bottom liquid of the distilling column having a temperature of not higher than 80° C. Further, by supplying a reflux liquid through the top of the distilling column or the middle stage of the column prior to the start of the temperature elevation of the distilling column, thereby preventing the polymerization of the easily polymerizing compound more effectively.

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: A method for stopping a purifying column handling an easily polymerizing compound-containing solution is disclosed, which method is characterized by lowering the inner oxygen concentration of the column below the limit of oxygen concentration by supplying an inert gas to the column while the concentration of the gas of easily polymerizing compound is in the range of 100% to the lower limit of the flammable range in volume % of the purifying column or by further supplying a reflux liquid thereby cooling the interior of the column at a rate in the range of 0.01-10° C./min. This invention enjoys exceptionally high economic value in respect that it is capable of preventing the easily polymerizing compound from the occurrence of polymerization in the purifying column, precluding the interior of the purifying column from being clogged by adhesion of a polymer, and moreover avoiding the possibility of explosion.

Abstract: The method and system of the present invention is designed to minimize exergy consumption consistent with a given level of product purity. For example, in a distillation system, the design employs a plurality of thermostatted trays which are maintained at a sequence of temperatures specified by finding the optimal control for an irreversible thermodynamic process. The specified temperatures at each tray are achieved with the help of a tandem heat pump which works over the range of required temperatures and which delivers the specified heat demands.

Abstract: A process for the distillative recovery of high purity monoethylene glycol from the hydrolysis, product of ethylene oxide by pressure dewatering, preferably in a battery, vacuum dewatering and subsequent purifying distillation, wherein during the vacuum dewatering an aqueous stream is withdrawn which contains-monoethylene glycol in a concentration below 1% by weight, preferably below 0.1% by weight, medium boilers and low boilers. The withdrawn aqueous stream is, optionally after further workup, removed from the system.

Abstract: A dividing-wall column having a dividing wall which is essentially disposed along the long direction of the column is proposed, which divides the column interior into a feed part, a take off part, an upper shared column part and a lower shared column part, with feed in whole or in part in the vaporous state of a mixture to be separated between the upper region of the feed part and the lower region of the feed part and/or side stream take off in whole or in part in the vaporous state between the upper region of the take off part and the lower region of the take off part, where if feed is in whole or in part in the vaporous state the cross-sectional area of the upper region of the feed part is increased by plane-parallel displacement of the dividing wall toward the upper region of the take off part, and/or if the side stream take off is in whole or in part in the vaporous state, the cross-sectional area of the lower region of the take off part is increased by displacement of the dividing wall toward the lower r

Abstract: This invention provides a concentrator capable of drawing out a concentrate of a constant concentration.

Abstract: A control method and apparatus for regulating the rate of vapor flow in the two adjacent sections of a dividing wall fractional distillation column are presented. The liquid level on a tray at the top of each section is used to control the rate of vapor flow through the tray. The liquid level is controlled by measuring the pressure differential across the tray in each section and varying the flow of liquid to this tray in response to the differential.

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: 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: 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 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: The present invention provides a method, and an apparatus, for forming a prescribed concentration of a substance in a mixture with a fluid, from a comparatively dilute mixture. The mixture is most preferably a solution of a solute in a solvent. The following summary and description generally discuss the invention in terms of a particularly preferred solution and a preferred use for that solution; however, in its broadest embodiments, the invention encompasses both the use for other solutions, and the use for a suspension of a solid substance in a fluid to form a mixture (which can also be referred to as a slurry). The invention provides for significant economic, safety and quality benefits over conventional evaporative systems.

Abstract: An extractive distillation tower 4 supplied with a feedstock containing butadiene and a solvent and for distilling the feedstock to separate and purify the butadiene.

Abstract: A method of distillation for separating a material which is solid at ambient temperature from a lower boiling and lower melting point material, and the apparatus.

Abstract: The present invention provides a distillation separation method whereby tertiary butyl acetate is separated by distillation as an overhead stream from a bottoms acetic acid stream with the proviso that water is incorporated in the system such that the bottoms acetic acid stream contains water in amount of 0.1 to 5 wt %.

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: A device allows for continuous regulation of the composition of a fluid mixture that includes at least two components of different polarities. The device is designed, for example, to be inserted in a separation system that the device supplies with a carrier fluid of stabilized composition. The device includes a storage tank (3) receiving a mixture coming from the separation system and at least one auxiliary vessel (6) containing one of the components of the mixture. To control the transfer of this component from auxiliary vessel (6) to storage tank (3), the device further includes at least one tubular capacitive sonde (CS) totally immersed in the fluid mixture, a sonde (TS) for measuring the temperature of the mixture, and a sonde (LS) for measuring the mixture level in storage tank (3).

Abstract: The present invention provides an industrially easy and economical method for purification of acrylic acid which enables to efficiently eliminate impurities from a crude acrylic acid containing aldehydes as the impurities while the formation of acrylic acid polymer is inhibited.

Abstract: A method permits concentration of a water-miscible organic liquid in a mixture of such liquid and water, with recovery of a desired concentrate of the water-miscible organic liquid and water, and a relatively clean water containing only a very low contest of the water-miscible organic liquid which enables disposal of the water in sewage systems, the method thus enhancing the ability to satisfy environmental concerns; the method has particular application to the recovery of a reusable glycol/water mixture from diluted spent aircraft deicer fluid (ADF).

Abstract: The invention relates to an improvement in a process in which chlorine and difluoromethane are present in a distillation column, for example, a fluorination reaction. By controlling the chlorine feed such that the concentration of chlorine relative to difluoromethane in the distillation column is maintained below about 22 weight percent (the flammability threshold for chlorine in a mixture of difluoromethane and chlorine), formation of a flammable difluoromethane/chlorine mixture may be minimized or avoided. The invention is particularly useful in a process for the preparation of difluoromethane wherein at least one distillation column separates difluoromethane from unreacted starting materials such as methylene chloride, hydrogen fluoride and monochloromonofluoromethane.

Abstract: A process for the separation of propylene from an input stream of C3 hydrocarbons containing propylene and methyl acetylene and/or propadiene and, optionally, C4 and/or higher hydrocarbons is described. The process includes subjecting the input stream to fractional distillation to separate propylene as an overhead stream leaving a bottoms stream containing the methyl acetylene and/or propadiene and the C4 and/or higher hydrocarbons, when present. A propane-containing stream is added to said input stream whereby propane is separated as part of the bottoms stream. The propylene content of the bottoms streams is maintained at less than 10% weight. The amount of propane added to the input stream is such that the weight of propane, propylene, and C4 and/or higher hydrocarbons, when present, in the bottoms stream is greater that the total weight of methyl acetylene and propadiene in the bottoms stream.

Abstract: A method of treating cleaning solvent used to clean mechanical parts. The method includes adding to the cleaning solvent a treating composition selected from the group of C.sub.5 -C.sub.14 alcohols, C.sub.2 -C.sub.8 dials, C.sub.10 -C.sub.14 polyols, and C.sub.4 -C.sub.14 glycol ethers, and mixtures thereof. A further embodiment includes the foregoing plus adding a clarifying agent from the group of aromatic, aliphatic and alkaryl sulfonic acids and sulfonic acid salts, esterified polyols, and alkyl phenol formaldehyde resins capped with alkoxy groups. The solvent is vaporized and condensed to effect recycling thereof without adding substituted quantities of treating composition to the solvent.

Abstract: A method and apparatus permits concentration of a water-miscible organic liquid in a mixture of such liquid and water, with recovery of a desired concentrate of the water-miscible organic liquid and water, and a relatively clean water containing only a very low content of the water-miscible organic liquid which enables disposal of the water in sewage systems, the method and apparatus thus enhancing the ability to satisfy environmental concerns; the method has particular application to the recovery of a reusable glycol/water mixture from diluted spent aircraft deicer fluid (ADF).

Abstract: In the continuous purification of a propylene oxide feedstock contaminated with water, methanol and acetone wherein an acetone buffer is established in the column, normal distillation conditions are maintained or restored during or after an upset by continuously monitoring predetermined distillation conditions in the acetone buffer zone, and adding additional acetone to the extractive distillation column when the monitored distillation condition deviates from a predetermined value by a predetermined amount.

Abstract: A process for the recovery of a carbonylation product from a liquid reaction composition of an iridium-catalysed carbonylation reaction of a carbonylatable reactant includes subjecting the composition to a vaporization with or without the addition of heat to produce a vapor-fraction and a liquid fraction, the vapor fraction includes carbonylation product and the liquid fraction has a water concentration of at least 0.5% by weight to stabilise the iridium catalyst.

Abstract: The mixed gas of a liquid raw material is stably supplied to not only one reactor but also a plurality of reactors as maintained with high purity at a fixed concentration.

Abstract: The invention is a method of introducing an aggressive liquid additive into a vapor-containing process stream including (a) heating the liquid additive by a heating means thereby producing a heated additive; (b) passing the heated additive to an injection quill in fluid communication with the vapor-containing process stream; and (c) passing the heated additive from the injection quill into the vapor-containing process stream.

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

Abstract: An apparatus for distillation of a liquid near or above its critical point wherein the liquid contains a dissolved solid. The apparatus includes a separation section wherein the liquid may be separated into a vapor and a liquid residue separated by a liquid surface. The apparatus includes a pump for pumping liquid into the apparatus so as to establish and maintain the liquid and vapor in the separation section at a desired pressure and a heat source for heating the liquid and vapor so as to establish a rising temperature profile in the separation section. The pump and heat source are cooperatively controllable for regulating the position of the liquid surface so that liquid residue can be discharged from immediately below the liquid surface.