Abstract: A process for separating a phase (A) comprising at least one ionic liquid from a phase (B), where phase (A) has a higher viscosity than phase (B), comprising: a) providing a stream (S1) comprising a dispersion (D1) in which phase (A) is dispersed in phase (B), b) introducing stream (S1) into a coalescing device (KV), where the inflow rate of stream (S1) is from 0.05 to 150 kg/(cm2*h) based on the average cross-sectional area of coalescing device (KV), wherein the packing density of coalescing device (KV) is from 50 to 500 kg/m3, separating phase (A) from phase (B) in coalescing device (KV), discharging a stream (S2) comprising at least 70% by weight of phase (A) from coalescing device (KV) and discharging a stream (S3) comprising at least 70% by weight of phase (B) from coalescing device (KV).

Abstract: Embodiments of an invention disclosed herein relate to processes utilizing solvent extraction to remove nitrogen containing compounds and optionally other components from feedstreams of olefins and paraffins.

Abstract: A method for cross connecting the lean solvent supply lines between the liquid liquid extraction (LLE) and the extractive distillation (ED) processes thereby using the LLE column as the outlet for removing accumulated heavy hydrocarbons (HCs) and polymeric materials from the solvent loop of both processes to maintain their solvent performance. The unique capabilities of the LLE column in rejecting heavy HCs from the solvent into a raffinate product stream that leaves the system enable the removal of the accumulated heavy HCs and polymeric materials from the closed solvent loop of the ED process when their lean solvent loop are cross connected. Cross connection requires minimum equipment change. In the revamped system, the solvent recovery column (SRC) in LLE process supplies lean solvent for the extractive distillation column while the SRC of the ED process supplies lean solvent for LLE column.

Abstract: Solvent regeneration to recover a polar hydrocarbon (HC) selective solvent substantially free of hydrocarbons (HCs) and other impurities from a solvent-rich stream containing selective solvent, heavy HCs, and polymeric materials (PMs) generated from reactions among thermally decomposed or oxidized solvent, heavy HCs, and additives is provided. A combination of displacement agent and associated co-displacement agent squeezes out the heavy HCs and PMs from the extractive solvent within a solvent clean-up zone. Simultaneously, a filter equipped with a magnetic field is positioned in a lean solvent circulation line to remove paramagnetic contaminants. The presence of the co-displacement agent significantly enhances the capability of the displacement agent in removing the heavy HCs and PMs from the extractive solvent.

Abstract: The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group —N—SO2—(CF2)nCF3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

Abstract: A continuous online process for rejuvenating whole stream of contaminated lean sulfolane in an extraction system is provided. A rejuvenator is installed in the solvent circulation loop to remove the contaminants continuously to keep the solvent clean, effective and less corrosive. The rejuvenator includes a high pressure vessel with a removable cover and a round rack with vertical stainless steel tubes fitted in the high pressure vessel. A magnetic bar is placed in each stainless steel tube. A screen cylinder is installed outside the ring of stainless steel tubes. As the contaminated sulfolane is passed through the rejuvenator, the rejuvenator picks up contaminants. The rejuvenator can be dissembled to remove the contaminants periodically. The rejuvenator is simple in construction, reliable in operation, and low in operation and maintenance costs. With this rejuvenator, the extraction system operates at high efficiency and high capacity without the dreaded corrosion.

Abstract: The invention concerns the control of solvent systems in processes and apparatus for the separation of aromatic hydrocarbons from non-aromatic hydrocarbons in liquid-liquid extraction, extractive distillation, and the combination thereof.

Abstract: The invention concerns the control of solvent systems in processes and apparatus for the separation of aromatic hydrocarbons from non-aromatic hydrocarbons in liquid-liquid extraction, extractive distillation, and the combination thereof.

Abstract: An energy efficient, high throughput process for aromatics recovery can be readily implemented by revamping existing sulfolane solvent extraction facilities, or constructing new ones, so as to incorporate unique process operations involving liquid-liquid extraction and extractive distillation. Current industrial sulfolane solvent based liquid-liquid extraction processes employ a liquid-liquid extraction column, an extractive stripping column, a solvent recovery column, a raffinate wash column, and a solvent regenerator. The improved process for aromatic hydrocarbon recovery from a mixture of aromatic and non-aromatic hydrocarbons requires transformation of the extractive stripping column into a modified extractive distillation column. The revamping incorporates the unique advantages of liquid-liquid extraction and extractive distillation into one process to significantly reduce energy consumption and increase process throughput.

Abstract: The regeneration of HF alkylation acid in an alkylation unit is improved by withdrawing a vapor stream from the HF regenerator tower and condensing the stream to form a liquid fraction which is accumulated in a side distillation zone; the collected liquid fraction, comprising HF acid, water and some stripping medium is distilled in a batch or continuous type operation to drive off the HF acid (along with stripping medium) and the vapor is returned to the regenerator-stripper vessel. The distillation of the sidedraw liquid is continued until the composition of the liquid attains the azeotropic value or as near to that value as desired. The azeotrope, comprising water and acid can then be dropped out of the distillation vessel for disposal by neutralization in the conventional way.

Abstract: The invention provides a method of extracting the hydrogen sulfide contained in a gas comprising aromatic hydrocarbons, wherein the following stages are carried out: a) contacting said gas with an absorbent solution so as to obtain a gas depleted in hydrogen sulfide and an absorbent solution laden with hydrogen sulfide, b) heating and expanding the hydrogen sulfide-laden absorbent solution to a predetermined temperature and pressure so as to release a gaseous fraction comprising aromatic hydrocarbons and to obtain an absorbent solution depleted in aromatic hydrocarbons, said temperature and pressure being so selected that said gaseous fraction comprises at least 50% of the aromatic hydrocarbons and at most 35% hydrogen sulfide contained in said hydrogen sulfide-laden absorbent solution, c) thermally regenerating the absorbent solution depleted in aromatic hydrocarbon compounds so as to release a hydrogen sulfide-rich gaseous effluent and to obtain a regenerated absorbent solution.

Abstract: An integrated, continuous process for transforming feedstock, e.g., reformate, which contains high levels of benzene into a low-benzene content feedstock that is suitable for gasoline blending initially removes benzene from the reformate by extractive distillation, then partially hydrogenating the high purity benzene into cyclohexane under mild conditions in a one-stage hydrogenation reactor, and thereafter recovering a cyclohexane product with high purity from the hydrogenation reactor effluent in a back-end purification step using extractive distillation. The initial or front-end separation step yields a low-benzene content reformate.

Abstract: The reduction in the sulfur-containing content of diesel fuel is achieved by oxidation in the presence of a catalyst followed by a liquid-liquid countercurrent extraction.

Abstract: Process for producing purified hydrocarbon gas from a gas stream comprising methane and acidic contaminants, which process comprises the steps cooling the gas stream by expansion to form a mixture comprising solid and/or liquid acidic contaminants and a vapour containing gaseous hydrocarbons and a reduced amount of acidic contaminants; separating the solid and/or liquid acidic contaminants from the first mixture, yielding partly purified gas; compressing the partly purified gas; and contacting the compressed partly purified gas with an absorbing liquid to yield the purified hydrocarbon gas.

Abstract: A catalytic distillation process for isomerizing and separating 1-alkenes from a mixed alkene stream. The process comprises contacting a mixed alkene stream comprising the 1-alkene and homologs thereof with a supported isomerization catalyst under isomerization/distillation conditions effective to convert at least a portion of the homologs to the 1-alkene, the isomerization/distillation conditions also being effective to produce a distillation overhead comprising a sufficient portion of the 1-alkene to drive isomerization of the homologs to the 1-alkene while maintaining the mixed alkene stream at least partially in liquid phase. The isomerization/distillation conditions are effective to recover a quantity of 1-alkene greater than an equilibrium quantity of 1-alkene recovered under isomerization conditions alone.

Abstract: An integrated, continuous process for transforming feedstock, e.g., reformate, which contains high levels of benzene into a low-benzene content feedstock that is suitable for gasoline blending initially removes benzene from the reformate by extractive distillation, then partially hydrogenating the high purity benzene into cyclohexane under mild conditions in a one-stage hydrogenation reactor, and thereafter recovering a cyclohexane product with high purity from the hydrogenation reactor effluent in a back-end purification step using extractive distillation. The initial or front-end separation step yields a low-benzene content reformate.

Abstract: According to the present invention, there is provided a process for inhibiting the polymerization of an aromatic vinyl compound which is capable of efficiently inhibiting the polymerization of an aromatic vinyl compound not only in an initial stage but also over a long term in the stage of producing, purifying, storing or transporting the aromatic vinyl compound, and which is excellent in handling. The present invention relates to a process for inhibiting the polymerization of an aromatic vinyl compound which requires the step of adding a 2-nitrophenol compound in combination with a sulfonic acid compound to the aromatic vinyl monomer during the stage of producing, purifying, storing or transporting the aromatic vinyl compound.

Abstract: This application relates to a composite solvent for separating aromatics by extractive distillation, comprising a main solvent, a solutizer and a modifier. Said solutizer is selected from any one or mixtures of any two of C8–C11 aromatics having different number of carbon atoms, the content of which is 3–39 wt %, and the number of carbon atoms of the lowest aromatic in the solutizer should be greater than that of the highest aromatic in the aromatics to be separated. When the solutizer is selected from any one of C8–C11 aromatics, the composite solvent contains 0.01–10.0 wt % of the modifier; when the solutizer is selected from mixtures of any two of C8–C11 aromatics having different number of carbon atoms, the composite solvent contains 0–10.0 wt % of the modifier. Said main solvent and modifier are independently selected from sulfolane derivatives, N-formyl morpholine, and N-methyl pyrrolidone, provided that the acidity and basicity of the modifier are opposite to those of the main solvent.

Abstract: A process for separating a feed mixture comprising at least one aromatic hydrocarbon and at least one non-aromatic hydrocarbon by extractive distillation (ED) utilizing a solvent mixture comprising sulfolane and at least one co-solvent. The co-solvent is an alkyl sulfolane having from 4 to 8 carbon atoms per molecule. The solvent mixture is added to the top of the ED column, and the feed mixture is added at a point on the ED column that is lower than the point where the solvent mixture is added. Extractive distillation is performed, and the aromatic and non-aromatic hydrocarbons are separated.

Abstract: The invention relates to a distillation process composition at least partially separating mixtures of aromatic and non-aromatic hydrocarbon compounds employing an extractive distillation composition comprising: a. at least one organic sulfoxide of the formula R1—SO—R2, and b. at least one acrylic sulfone of the formula R3—SO2—R4  wherein R1, R2, R3, and R4 have at least one carbon atom and can be the same or different, and  wherein the at least one organic sulfoxide is present in an amount effective to provide improved separation of the aromatic and non-aromatic hydrocarbon compounds, as compared to a process employing the same extractive distillation composition not comprising the organic sulfoxide.

Abstract: Methods for separating olefins from non-olefins, such as paraffins, including cycloparaffins, oxygenates and aromatics, are provided. The methods use metal salts to complex olefins, allowing the non-olefins to be separated by a variety of methods, including decantation and distillation. The metal salts are dissolved in ionic liquids, which tend to have virtually no vapor pressure, and which poorly solubilize the non-olefins. Accordingly, the non-olefins phase separate well, and can be distilled without carrying over any of the ionic liquid into the distillate. Preferred salts are Group IB salts, more preferably silver salts. A preferred silver salt is silver tetrafluoroborate. Preferred ionic liquids are those which form stable solutions or dispersions of the metal salts, and which do not dissolve the non-olefins. Further, if the olefins are subject to isomerization, the ionic liquid is preferably relatively non-acidic.

Abstract: The invention relates to extractive distillation compositions for separating a mixture of hydrocarbon compounds, wherein the extractive distillation composition includes at least one alkylene glycol compound, and at least one compatibility agent, wherein the compatibility agent is selected from materials having polar parameters and hydrogen bonding parameters such that the extractive distillation composition provides improved separation of the hydrocarbon compounds, as compared to the use of the extractive distillation composition without the compatibility agent.

Abstract: An improved process for the recovery of aromatic compounds from a mixture containing aromatic and non-aromatic compounds and method for retrofitting existing equipment for the same is provided. The improved process comprises the steps of recovering aromatic compounds via parallel operation of a hybrid extractive distillation/liquid-liquid extractor operation and variations thereof. Methods of quickly and economically retrofitting existing recovery process equipment for use with the improved aromatic recovery process are also disclosed.

Abstract: The invention relates to methods for enhanced extractive distillation of hydrocarbons that employ extrative distillation compositions comprising sulfolane or sulfolane derivatives in comination with compatibility agents.

Abstract: The invention relates to an extractive distillation composition for at least partially separating a mixture of hydrocarbon compounds comprising:

Abstract: A method for separating at least a benzothiophene compound from a hydrocarbon mixture is disclosed. The method includes contacting the mixture of a fraction obtained therefrom with a reagent including an acceptor complexing agent &pgr;, to obtain a donor-acceptor complex between the acceptor complexing agent and the benzothiophene compound; and separating the complex from the mixture, or from the fraction, to obtain a fraction depleted or purified in the benzothiophene compound.

Abstract: The present invention relates to a method of purifying 1,3,5-triisopropylbenzene that comprises combining inpure 1,3,5-triisopropylbenzene with a sulfonating agent to form a reaction mixture, mixing the reaction mixture at a temperature in the range of about 0° C. to about 50° C., and collecting the purified 1,3,5-triisopropylbenzene.

Abstract: The present invention relates to a method of purifying 1,3,5-triisopropylbenzene that comprises combining impure 1,3,5-triisopropylbenzene with a sulfonating agent to form a reaction mixture, mixing the reaction mixture at a temperature at about 20° C. or above, and collecting the purified 1,3,5-triisopropylbenzene.

Abstract: A process for separating a feed mixture comprising at least one aromatic hydrocarbon and at least one non-aromatic hydrocarbon by extractive distillation (ED) utilizing a solvent mixture comprising sulfolane and at least one co-solvent. The co-solvent is an alkyl sulfolane having from 4 to 8 carbon atoms per molecule. The solvent mixture is added to the top of the ED column, and the feed mixture is added at a point on the ED column that is lower than the point where the solvent mixture is added. Extractive distillation is performed, and the aromatic and non-aromatic hydrocarbons are separated.

Abstract: A process for removing sulfone from a liquid hydrocarbon containing a concentration of sulfone by mixing a liquid acid therewith and thereafter separating the resulting admixture into an acid phase and a hydrocarbon phase. The hydrocarbon phase has a concentration of sulfone less than such concentration in the liquid hydrocarbon.

Abstract: A process for the desulfurization of hydrocarbonaceous oil wherein the hydrocarbonaceous oil and a recycle stream containing sulfur-oxidated compounds is contacted with a hydrodesulfurization catalyst in a hydrodesulfurization reaction zone to reduce the sulfur level to a relatively low level and then contacting the resulting hydrocarbonaceous stream from the hydrodesulfurization zone with an oxidizing agent to convert the residual, low level of sulfur compounds into sulfur-oxidated compounds. The residual oxidizing agent is decomposed and the resulting hydrocarbonaceous oil stream containing the sulfur-oxidated compounds is separated to produce a stream containing the sulfur-oxidated compounds and a hydrocarbonaceous oil stream having a reduced concentration of sulfur-oxidated compounds. At least a portion of the sulfur-oxidated compounds is recycled to the hydrodesulfurization reaction zone.

Abstract: A process for the desulfurization of hydrocarbonaceous oil wherein the hydrocarbonaceous oil is contacted with a hydrodesulfurization catalyst in a hydrodesulfurization reaction zone to reduce the sulfur level to a relatively low level and then contacting the resulting hydrocarbonaceous stream from the hydrodesulfurization zone with an oxidizing agent to convert the residual, low level of sulfur compounds into sulfur-oxidated compounds. The resulting hydrocarbonaceous oil stream containing the sulfur-oxidated compounds is separated after decomposing any residual oxidizing agent to produce a stream containing the sulfur-oxidated compounds and a hydrocarbonaceous oil stream having a reduced concentration of sulfur-oxidated compounds.

Abstract: A system and/or process for decreasing the level of at least one organic fluoride present in a hydrocarbon mixture by first passing the hydrocarbon mixture to an eductor and educting into the hydrocarbon mixture a catalyst comprising a volatility reducing additive and hydrofluoric acid to produce a hydrocarbon-catalyst mixture, permitting the hydrocarbon-catalyst mixture to undergo a phase separation to produce a hydrocarbon phase having a lower concentration of at least one organic fluoride than the hydrocarbon mixture and to produce a catalyst phase, and withdrawing at least a portion of the hydrocarbon phase to thereby form a hydrocarbon product stream, are disclosed. In an alternate embodiment, a system and/or process for controlling the concentration of at least one organic fluoride and/or the RON of the hydrocarbon mixture by adjusting the amount of volatility reducing additive present in the catalyst are disclosed.

Abstract: Disclosed is a process for separating at least one cycloalkane containing 5-10 carbon atoms per molecule from at least one close-boiling alkane by extractive distillation of a feed consisting essentially of said at least one cycloalkane and said at least one alkane, the improvement comprising the use of certain pyrrolidones, certain morpholines, sulfoxides, sulfolanes, glycol compounds, or mixtures thereof, and optionally water; wherein said extractive distillation process produces (i) an overhead distillate product which contains a smaller volume percentage of said at least one cycloalkane and a larger volume percentage of said at least one alkane than said feed, and (ii) a bottoms product which contains said solvent and a larger volume percentage of said at least one cycloalkane and a smaller volume percentage of said at least one alkane than said feed; and wherein said at least one cycloalkane is separated from said solvent and recovered from said bottoms product.

Abstract: An extraction process and an apparatus for separating aromatic compounds contained in a liquid hydrocarbon feedstock where the feedstock feed into the lower part of an extraction column is brought into intimate countercurrent contact therein with a third liquid and at least partially with at least one structured packing element (31) of the static mixer type contained in the upper part of the extraction column. Such third liquid (feed to the top of said column) is in the form of a solvent which is immiscible with the feedstock except for being capable of extracting the aromatic compounds. At least part of the extract phase rich in solvent and aromatic compounds is separated by liquid--liquid separation (26), preferably by gravity type decantation, into a phase rich in solvent and essentially depleted of raffinate, which is removed, and a phase rich in raffinate and impoverished in solvent, which is recycled to the extraction step. The extraction process is typically to be used to formulate lubricant oils.

Abstract: Aromatic hydrocarbons are selectively extracted from lube oil stocks comprising mixtures of same with non-aromatic hydrocarbons using tetramethyl sulfoxide as the extraction solvent. The oils so extracted are the heavier oils, those boiling above about 200.degree. C. and identified as being at least lube base stock grade 60N and higher.

Abstract: Disclosed is a process for recovering styrene from a feedstock containing at least styrene, ethylbenzene, and one or more aromatic or non-aromatic hydrocarbon compounds which includes separating said feedstock into a first stream relatively more concentrated in styrene than said feedstock and a second stream relatively more concentrated in ethylbenzene than said feedstock, recovering styrene from said first stream to produce a styrene product stream, dehydrogenating the ethylbenzene of said second stream to produce additional styrene, and recovering said additional styrene. The feedstock may be separated into said first and second streams by a process selected from the class consisting of extractive distillation, azeotropic distillation, distillation, liquid-liquid extraction, chemical complex formation, membrane separation, and combinations thereof, and the additional styrene may be recovered by recycling it into said feedstock.

Abstract: An extractive distillation process for separating at least one substituted unsaturated aromatic from a pyrolysis gasoline mixture, containing said aromatic and at least one close-boiling aromatic or non-aromatic hydrocarbon, employing a two part extractive solvent, the first part selected from propylene carbonate, sulfolane (tetramethylene sulfone), methyl carbitol, 1-methyl-2-pyrrolidinone, 2-pyrrolidinone and mixtures thereof, and the second portion consisting of water.

Abstract: A process is directed to the removal of impurities such as sulfur compounds, oxygenates, and/or olefins from a light paraffin hydrocarbon feedstock such as a C.sub.4 -C.sub.6 fraction, which may be used subsequently in an isomerization process in an integrated complex for the production of ethers such as MTBE and TAME. The hydrocarbon feedstream is passed to a removal zone wherein the hydrocarbon feedstream is contacted with a selective solvent for the removal of the impurities comprising at least one of sulfur compounds, oxygenates and olefins to provide a rich solvent stream and a treated hydrocarbon stream. The rich solvent comprising the trace impurities is contacted with a stripping medium stream to regenerate the selective solvent in a stripping zone. The removal zone may be a liquid-liquid extraction zone or a gas absorption zone.

Abstract: Disclosed is a process for separating sulfone from a hydrocarbon stream containing a small concentration sulfone by using water as an extraction solvent. The extraction solvent, laden with the removed sulfone, is further processed to separate the extraction solvent and water to thereby produce a sulfone product suitable for reused in an alkylation process or for sale as a dry sulfone end-product.

Abstract: A safe and reliable method of removing halogenated aromatic compounds present in small amounts in hydrocarbon oil constituted mainly by non-aromatic hydrocarbon oil. The hydrocarbon oil is contacted with a heat-resistant alkaline polar solvent in the presence of an alkaline at a temperature ranging from about 100.degree. C. to 300.degree. C., and the non-aromatic hydrocarbon oil and heat-resistant alkaline polar solvent are then separated, thereby removing the halogenated aromatic compounds from the hydrocarbon oil.

Abstract: Disclosed is a process for removing acid soluble oils, produced as an undesirable by-product of an HF catalyzed alkylation reaction, from a fluid containing a sulfone compound. The process includes the use of hydrocarbons to remove ASO from the sulfone-containing fluid.

Abstract: Benzene is difficult to separate from cyclohexane or cyclohexene by conventional distillation or rectification because of the close proximity of their boiling points. Benzene can be readily separated from cyclohexane or cyclohexene by using extractive distillation. Effective agents are: for benzene from cyclohexane, methyl acetoacetate; for benzene from cyclohexene, ethyl acetoacetate.

Abstract: Heptane is difficult to separate from 1-heptene by conventional distillation or rectification because of the proximity of their boiling points. Heptane can be readily separated from 1-heptene by extractive distillation. Effective agents are diacetone alcohol, ethyl butyrate and dimethylsulfoxide.

Abstract: Benzene and other aromatics are separated from a stream of mixed hydrocarbons containing both aromatics and non-aromatics by extractive distillation with a solvent system containing dimethyl sulfoxide and optionally a co-solvent, preferably water, followed by distillation stripping of the aromatics from the enriched solvent system, and recycle of the lean solvent system to the extractive distillation step.

Abstract: Hexane is difficult to separate from vinyl acetate and/or methyl acrylate by conventional distillation or rectification because of the closeness of their boiling points. Hexane can be readily separated from vinyl acetate and/or methyl acrylate by extractive distillation. Effective agents are dimethylsulfoxide and dimethylformamide.

Abstract: The present invention provides a method for separating conjunct polymers which are formed as byproducts of acid catalyzed isoparaffin-olefin alkylation and sulfolane from a mixture containing conjunct polymers, sulfolane, and hydrofluoric acid, and for minimizing accumulation of conjunct polymeric byproducts in the recycled acid catalyst.

Abstract: Disclosed is a process for removing acid soluble oils, produced as an undesirable by-product of an acid catalyzed alkylation reaction, from a mixture containing a strong acid and methanesulfonic acid. The process includes the use of water to induce the formation of the two immiscible liquid phases of ASO and methanesulfonic acid with water. The two immiscible phases can subsequently be separated from each other.

Abstract: Heptane cannot be removed from heptane-vinyl acetate mixtures by distillation because of the minimum boiling azeotrope. Heptane can be readily removed from vinyl acetate by extractive distillation. Typical effective agents are dimethylsulfoxide, phenol, diisobutyl ketone and hexyl acetate.

Abstract: The present invention provides a method for separating conjunct polymers and sulfolane from a mixture containing conjunct polymers, sulfolane, and hydrofluoric acid comprising the sequential steps of:(a) separating hydrofluoric acid from said mixture to provide an intermediate stream containing less than about 30 percent hydrofluoric acid by weight;(b) gravitationally separating said intermediate stream into a sulfolane-enriched stream and a conjunct polymer-enriched stream;(c) contacting said sulfolane-enriched stream with a polar extraction solvent to provide an extract stream enriched in sulfolane and a raffinate stream enriched in conjunct polymers;(d) stripping the polar extraction solvent from said sulfolane-enriched extract stream; and(e) recovering sulfolane from said enriched stream of step (d).