US3434936A - Method of separating aromatic compounds from hydrocarbon mixtures containing the same by extractive distillation with an n-substituted morpholine - Google Patents

Method of separating aromatic compounds from hydrocarbon mixtures containing the same by extractive distillation with an n-substituted morpholine Download PDF

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Publication number
US3434936A
US3434936A US691363A US3434936DA US3434936A US 3434936 A US3434936 A US 3434936A US 691363 A US691363 A US 691363A US 3434936D A US3434936D A US 3434936DA US 3434936 A US3434936 A US 3434936A
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aromatic compounds
hydrocarbons
solvent
extractive distillation
column
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US691363A
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Guenter Luther
Martin Schulze
Klaus Richter
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Heinrich Koppers GmbH
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Heinrich Koppers GmbH
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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G21/00—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents
    • C10G21/06—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents characterised by the solvent used
    • C10G21/12—Organic compounds only
    • C10G21/20—Nitrogen-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/04—Purification; Separation; Use of additives by distillation
    • C07C7/05—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds
    • C07C7/08—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds by extractive distillation

Definitions

  • the present invention relates to a method of separating aromatic compounds from hydrocarbon mixtures containing the same, whereby the proportion of aromatic compounds in the mixture may vary greatly from relatively small to relatively very large proportions, and wherein the non-aromatic constituents in the mixture generally will include paraflins and/or cycloparaifins and/0r olefins, and also may include organic sulfur compounds.
  • the separation of the aromatic compounds is carried out in accordance with the present invention by extractive distillation.
  • the method of the present invention is intended to serve for:
  • the method of the present invention may be utilized in such cases where the purity of the separated aromatic fractions is the essential consideration, and also in such cases where the purity of the non-aromatic (parafiin) fraction is of prime importance.
  • the last-mentioned method is excellently suited for working up hydrocarbon mixtures which contain a relatively large proportion of aromatic compounds, for instance so-called pressure raifinates which have aromatic compound contents of about 96%.
  • the working up of hydrocarbon mixtures with relatively low content of aromatic compounds, for instance so-called reformates which contain between 4 and 10% benzene is possible by the last-mentioned method only if a heavy aromatic fraction is added to the propylene carbonate in order to increase the solubilizing action. This measure, however, reduces the selectivity of the propylene carbonate as a solvent and furthermore requires the circulation of large quantities of solvent in the extractive distillation arrangement.
  • -It is an object of the present invention to provide an extractive distillation process which, due to the specific selective solvent utilized, will make it possible to work up hydrocarbon mixtures within the entire technically accruing range of concentration of aromatic compounds, either so as to obtain pure aromatic fraction, or to remove residual aromatic compounds from a pure non-aromatic or paraflinic fraction.
  • the present invention proposes to separate aromatic compounds from a mixture of hydrocarbons which consists partly of aromatic compounds, by subjecting the mixture to extractive distillation in the presence of a selective solvent for the aromatic compounds which selective solvent is an N-snbstituted morpholine which has up to 7 carbon atoms in the substituent group, whereby an extract will be obtained which consists essentially of the aromatic compounds dissolved in the substituted morpholine compound.
  • the thus-obtained extract may then be recovered and if the original hydrocarbon mixtures included unsaturated compounds which partly may have been incorporated in the extract, the extract may then be subjected to hydrogenation.
  • the recovered extract may then be freed of solvent, the solvent separately recovered by distillation and, if the original mixture contained unsaturated or heterogeneous compounds, it will frequently be desirable to subject the recovered extract prior to distilling-off the solvent, to washing with sulfuric acid or to treatment with a bleaching earth.
  • the single figure of the drawing is a schematic elevational representation of an arrangement for carrying out the method of the present invention.
  • an aromatic cornponuds-containing mixture of hydrocarbons is separated into aromatic and non-aromatic compounds by extractive distillation utilizing as the selective solvent for the aromatic fraction one or more N-substituted morpholines which contain no more than 7 carbon atoms in the substituent.
  • the substituents may be of straight chain, branched or ring-shaped structure.
  • substituent groups with not more than 4 carbon atoms.
  • the N-substituted morpholines may be used either individually or in the form of mixtures thereof.
  • the solvents which are utilized in accordance with the present invention i.e., the N-substituted morpholines with not more than 7 carbon atoms in the substituent group, all have more or less the same boiling range; however, they differ with respect to their solubilizing action and their selectivity as a solvent.
  • solubilizing conditions can be adjusted which are geared to the concentration of aromatic compounds in the starting mixture of hydrocarbons which is to be worked up. This can be done without reducing the selectivity of the solvent mixture as would be the case by adding a heavy or high molecular weight aromatic compound in accordance with the prior art described further above. It is an additional advantage of the method of the present invention that relatively small amounts of solvent have to be recirculated due to the fact that it is not necessary to add heavy aromatic compounds for carrying out the extractive distillation.
  • the extractive distillation is preferably carried out without reflux of hydrocarbons which have been distilled off.
  • condensate is not added to the raffinate phase at the head of the extractive distillation column.
  • the column thus works only with so-called interior reflux which adjusts itself by condensation of extraction agent or solvent within the column.
  • the reflux which is added at the head of the extractive distillation column mixes with the extraction agent or solvent and reduces the selectivity of the latter. Furthermore, it also requires to again vaporize the refluxed hydrocarbons and this increases the energy demands of the system. This again requires that the sump of the extractive distillation column must be heated more strongly so that also a correspondingly higher proportion of the aromatic compounds located in the sump will be vaporized. Since these vapors also have a correspondingly higher temperature, they will rise higher in the extractive distillation column before they will be condensed again. This also impairs efliciency or completeness of the separation of the aromatic compounds.
  • the starting material i.e., the starting mixture of hydrocarbons
  • the regeneration and recovery of the selective solvent or solvent mixture is carried out in per se known manner by distillation. If the solvent is contaminated with unsaturated compounds which may have been originally contained in the starting material, it is preferred to carry out regeneration of the solvent by first hydrogenating the same, for instance in the sump of the regenerating col umn, followed by distillation.
  • Hydrogenation of the unsaturated compounds-containing phase for instance by means of a conventional nickel catalyst, is connected with the further advantage that thereby unsaturated hydrocarbons which may be contained in the solvent as impurities will be partially hydrogenated or subjected to hydrogenating cracking.
  • unsaturated hydrocarbons which may be contained in the solvent as impurities will be partially hydrogenated or subjected to hydrogenating cracking.
  • dicyclopentadiene will be decomposed into 2 moles of cyclopentane.
  • the saturated hydrocarbons which are formed by the hydrogenation in the sump phase can be easily separated from the solvent upon recycling of the latter into the extractive distillation column.
  • the extractive distillation column 1 may be a bubble tray column with sixty trays.
  • the starting product is introduced through conduit 2 into the middle of the column, for instance at the twenty-first, thirty-first or forty-first tray counted from the top of the column.
  • the non-aromatic compounds are withdrawn from the head of the distillation column through conduit 3.
  • Recycled solvent is introduced through conduit 4 at the uppermost tray of column 1.
  • only recycled solvent and no condensed hydrocarbons are reintroduced into column 1.
  • the aromatic compounds and the solvent carrying the same are withdrawn through column 5 at the sump or bottom of column 1 and conveyed to stripper 6 which also consists of a bubble tray column with forty trays.
  • Introduction of the extract consisting of the aromatic compounds dissolved in the solvent is carried out at the fifteenth tray counted from the top of column 6.
  • the pure aromatic compounds are withdrawn through conduit 7 at the head of column 6 or a few trays below the head.
  • the aromatic compounds may be, prior to being finally withdrawn through conduit 15, subjected to a sulfuric acid or bleaching earth treatment in a suitable treating vessel 8 of per se conventional structure. Furthermore, if necessary, the higher boiling aromatic compounds may be conveyed through conduit 9 to stripper 10. Stripper column 10 serves for further purification of the higher boiling aromatic compounds which were withdrawn through conduit 9. These higher boiling aromatic compounds will accure and be concentrated in the bottom portion of stripper column 10 whereas any lower boiling constituents may -be withdrawn at the head of stripper column or, if desired, recycled into stripper column 6.
  • the withdrawal of the pure final product i.e., the pure aromatic compounds, is carried out through conduit 11.
  • the solvent which has thus been freed of aromatic compounds is withdrawn at the bottom of column 6 and recycled through conduit 4 to extractive distillation column 1.
  • a partial stream of the distilled-off solvent may-if necessary be introduced through conduit 12 at one of the intermediate trays of regenerative column 13.
  • nondistillable impurities may be withdrawn through conduit 17, whereas the solvent may be withdrawn at the head or two trays below the head of regenerative column 13 and passed through conduit 14 into conduit 4 and into the recirculation system.
  • the regenerating column 13 may also serve as a pressure container for hydrogenation, in which case the trays may include catalyst beds so that the regenerative column 13 will also serve for hydrogenation of the impurities particularly non-distillable impurities. It is also possible to carry out distillative regeneration and the above-described hydrogenation in the bottom portion of the regenerative column 13 in simultaneous manner.
  • Conduit 16 serves for introducing hydrogen gas required for the above-described hydrogenation into regenerative column 13.
  • n-C7 hydrocarbons Isa-g Chydrocarbons up to boiling point poin l1 n-0 hydrocarbons Iso-C hydrocarbons Toluene below in table form, whereby Table I will serve to de- Xylenes- Solidifioatwn point scribe the essential operative data.
  • Method of separating aromatic compounds from a mixture of hydrocarbons consisting partly of aromatic compounds and also including non-aromatic hydrocarbons comprising the steps of subjecting said mixture in an extractive distillation means to extractive distillation in the presence of a selective solvent for said aromatic compounds, said selective solvent being selected from the group consisting of N-substituted morpholines having up to 7 carbon atoms in the substituent, so as to obtain extract bottoms consisting predominantly of said aromatic compounds dissolved in said selective solvent and simultaneously to distill-off non-aromatic hydrocarbons; recovering said extract bottoms consisting predominantly of said aromatic compounds dissolved in said selective solvent; and recovering the distilled-off nonaromatic hydrocarbons outside the extractive distillation means in the absence of refluxing said distilled-off nonaromatic hydrocarbons.
  • a method as defined in claim 2, wherein the recovery of the distilled-01f non-aromatic hydrocarbons comprises condensing the distilled-oif non-aromatic hydrocarbons outside the extractive distillation means.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US691363A 1966-12-19 1967-12-18 Method of separating aromatic compounds from hydrocarbon mixtures containing the same by extractive distillation with an n-substituted morpholine Expired - Lifetime US3434936A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1568940A DE1568940C3 (de) 1966-12-19 1966-12-19 Verfahren zur Abtrennung von Aromaten aus Kohlenwasserstoffgemischen beliebigen Aromatengehaltes

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US (1) US3434936A (de)
AT (1) AT280988B (de)
BE (1) BE707674A (de)
DE (1) DE1568940C3 (de)
ES (1) ES348324A1 (de)
GB (1) GB1139630A (de)
NL (1) NL154191B (de)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3673081A (en) * 1969-02-19 1972-06-27 Koppers Gmbh Heinrich Process for separating saturated hydrocarbons and olefins
US3953300A (en) * 1972-11-29 1976-04-27 Snam Progetti, S.P.A. Process for separating a high purity vinyl aromatic hydrocarbon from hydrocarbon mixtures containing the same
US4009084A (en) * 1969-07-18 1977-02-22 Snam Progetti S.P.A. Process for the separation of diolefins from mixtures containing the same
US4076594A (en) * 1975-10-11 1978-02-28 Basf Aktiengesellschaft Purification of formic acid by extractive distillation
US4201633A (en) * 1977-05-12 1980-05-06 Snamprogetti S.P.A. Separating aromatic hydrocarbons from mixtures containing them
US5180474A (en) * 1991-03-23 1993-01-19 Krupp Koppers Gmbh Method of separation of aromates by extractive distillation
US5401365A (en) * 1992-10-28 1995-03-28 Chevron Research & Technology High purity benzene production using extractive distillation
US6007707A (en) * 1996-07-31 1999-12-28 Krupp Uhde Gmbh Process for the recovery of pure hydrocarbons from a hydrocarbon mixture
US6358402B1 (en) 1999-12-28 2002-03-19 Exxonmobil Research And Engineering Company Extractive distillation process for the reduction of sulfur species in hydrocarbons streams
US20070299294A1 (en) * 2006-06-27 2007-12-27 Amt International, Inc. Integrated process for removing benzene from gasoline and producing cyclohexane
US20100236916A1 (en) * 2007-08-17 2010-09-23 Uhde Gmbh Recovery of benzene and benzene derivatives from gasoline fraction and refinery streams
US9068125B2 (en) 2009-03-11 2015-06-30 Thyssenkrupp Uhde Gmbh Process for the recovery of pure aromatics from hydrocarbon fractions containing aromatics
CN114470834A (zh) * 2020-10-27 2022-05-13 湖南中岭化工有限责任公司 一种粗苯加氢萃取装置

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3409030A1 (de) * 1984-03-13 1985-09-19 Krupp Koppers GmbH, 4300 Essen Verfahren zur abtrennung von aromaten aus kohlenwasserstoffgemischen beliebigen aromatengehaltes
DE3409307A1 (de) * 1984-03-14 1985-09-19 Krupp Koppers GmbH, 4300 Essen Verfahren zur abtrennung von aromaten aus kohlenwasserstoffgemischen beliebigen aromatengehaltes
DE3602240A1 (de) * 1986-01-25 1987-07-30 Krupp Koppers Gmbh Verfahren zur abtrennung von aromaten aus kohlenwasserstoffgemischen beliebigen aromatengehaltes
DE3612384A1 (de) * 1986-04-12 1987-10-15 Krupp Koppers Gmbh Verfahren zur herstellung eines zur verwendung als blendingkomponente fuer vergaserkraftstoffe geeigneten aromatenkonzentrates
DE3930992A1 (de) * 1989-09-16 1991-03-28 Erdoelchemie Gmbh Verfahren zur abtrennung von aromaten
DE3942950A1 (de) * 1989-12-23 1991-06-27 Krupp Koppers Gmbh Verfahren zur gleichzeitigen gewinnung von reinem benzol und reinem tuluol
DE4437702C1 (de) * 1994-10-21 1995-11-23 Krupp Koppers Gmbh Verfahren zur Gewinnung von reinem Benzol und reinem Toluol
EP1022046A1 (de) 1999-01-22 2000-07-26 Krupp Uhde GmbH Verfahren zur Entfernung von Kohlendioxid, Schwefelverbindungen, Wasser und aromatischen und höheren aliphatischen Kohlenwasserstoffen aus technischen Gasen
US9005405B2 (en) 2012-03-01 2015-04-14 Cpc Corporation, Taiwan Extractive distillation process for benzene recovery
EP4180103A1 (de) * 2021-11-12 2023-05-17 Thyssenkrupp Uhde Engineering Services GmbH Verfahren zur entleerung eines lösungsmittel-regenerierungs-behälters sowie vorrichtung

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB548734A (en) * 1941-04-21 1942-10-22 Shell Dev A process for the separation and recovery of hydrocarbons of different degrees of saturation
US2313537A (en) * 1941-07-12 1943-03-09 Allied Chem & Dye Corp Recovery of xylene from oils containing the same
US2439777A (en) * 1944-09-18 1948-04-13 Union Oil Co Separation of thiophenes from hydrocarbons by azeotropic distillation
US3200165A (en) * 1961-07-08 1965-08-10 Metallgesellschaft Ag Recovery of aromatic and olefinic hydrocarbons
US3299158A (en) * 1960-06-04 1967-01-17 Metallgesellschaft Ag Production of pure aromatic hydrocarbons
US3325399A (en) * 1964-10-14 1967-06-13 Snam Spa Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same
US3366568A (en) * 1964-09-29 1968-01-30 Metallgesellschaft Ag Recovery of aromatics by extraction or extractive distillation with solvent mixtures

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB548734A (en) * 1941-04-21 1942-10-22 Shell Dev A process for the separation and recovery of hydrocarbons of different degrees of saturation
US2313537A (en) * 1941-07-12 1943-03-09 Allied Chem & Dye Corp Recovery of xylene from oils containing the same
US2439777A (en) * 1944-09-18 1948-04-13 Union Oil Co Separation of thiophenes from hydrocarbons by azeotropic distillation
US3299158A (en) * 1960-06-04 1967-01-17 Metallgesellschaft Ag Production of pure aromatic hydrocarbons
US3200165A (en) * 1961-07-08 1965-08-10 Metallgesellschaft Ag Recovery of aromatic and olefinic hydrocarbons
US3366568A (en) * 1964-09-29 1968-01-30 Metallgesellschaft Ag Recovery of aromatics by extraction or extractive distillation with solvent mixtures
US3325399A (en) * 1964-10-14 1967-06-13 Snam Spa Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3673081A (en) * 1969-02-19 1972-06-27 Koppers Gmbh Heinrich Process for separating saturated hydrocarbons and olefins
US4009084A (en) * 1969-07-18 1977-02-22 Snam Progetti S.P.A. Process for the separation of diolefins from mixtures containing the same
US3953300A (en) * 1972-11-29 1976-04-27 Snam Progetti, S.P.A. Process for separating a high purity vinyl aromatic hydrocarbon from hydrocarbon mixtures containing the same
US4076594A (en) * 1975-10-11 1978-02-28 Basf Aktiengesellschaft Purification of formic acid by extractive distillation
US4201633A (en) * 1977-05-12 1980-05-06 Snamprogetti S.P.A. Separating aromatic hydrocarbons from mixtures containing them
US5180474A (en) * 1991-03-23 1993-01-19 Krupp Koppers Gmbh Method of separation of aromates by extractive distillation
US5401365A (en) * 1992-10-28 1995-03-28 Chevron Research & Technology High purity benzene production using extractive distillation
US6007707A (en) * 1996-07-31 1999-12-28 Krupp Uhde Gmbh Process for the recovery of pure hydrocarbons from a hydrocarbon mixture
US6358402B1 (en) 1999-12-28 2002-03-19 Exxonmobil Research And Engineering Company Extractive distillation process for the reduction of sulfur species in hydrocarbons streams
EP1250400A1 (de) * 1999-12-28 2002-10-23 ExxonMobil Research and Engineering Company Extraktionsdestillationsverfahren zur entfernung von schwefelverbindungen in kohlenwasserstoffströmen
JP2003518547A (ja) * 1999-12-28 2003-06-10 エクソンモービル リサーチ アンド エンジニアリング カンパニー 炭化水素ストリームの硫黄種を低減するための抽出蒸留方法
EP1250400A4 (de) * 1999-12-28 2004-08-04 Exxonmobil Res & Eng Co Extraktionsdestillationsverfahren zur entfernung von schwefelverbindungen in kohlenwasserstoffströmen
JP4666864B2 (ja) * 1999-12-28 2011-04-06 エクソンモービル リサーチ アンド エンジニアリング カンパニー 炭化水素ストリームの硫黄種を低減するための抽出蒸留方法
US20070299294A1 (en) * 2006-06-27 2007-12-27 Amt International, Inc. Integrated process for removing benzene from gasoline and producing cyclohexane
US7790943B2 (en) 2006-06-27 2010-09-07 Amt International, Inc. Integrated process for removing benzene from gasoline and producing cyclohexane
US20100236916A1 (en) * 2007-08-17 2010-09-23 Uhde Gmbh Recovery of benzene and benzene derivatives from gasoline fraction and refinery streams
US8536397B2 (en) 2007-08-17 2013-09-17 Uhde Gmbh Recovery of benzene and benzene derivatives from gasoline fraction and refinery streams
US9068125B2 (en) 2009-03-11 2015-06-30 Thyssenkrupp Uhde Gmbh Process for the recovery of pure aromatics from hydrocarbon fractions containing aromatics
CN114470834A (zh) * 2020-10-27 2022-05-13 湖南中岭化工有限责任公司 一种粗苯加氢萃取装置

Also Published As

Publication number Publication date
DE1568940C3 (de) 1978-12-07
GB1139630A (en) 1969-01-08
AT280988B (de) 1970-05-11
DE1568940B2 (de) 1974-01-31
ES348324A1 (es) 1969-03-01
DE1568940A1 (de) 1970-07-16
NL154191B (nl) 1977-08-15
NL6716968A (de) 1968-06-20
BE707674A (de) 1968-04-16

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