US3884769A - Process for purifying benzene and toluene by extractive azeotropic distillation - Google Patents

Process for purifying benzene and toluene by extractive azeotropic distillation Download PDF

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US3884769A
US3884769A US343108A US34310873A US3884769A US 3884769 A US3884769 A US 3884769A US 343108 A US343108 A US 343108A US 34310873 A US34310873 A US 34310873A US 3884769 A US3884769 A US 3884769A
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distillation
extraction solvent
column
solvent
process according
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Paul Mikitenko
Georges Cohen
Lionel Asselineau
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IFP Energies Nouvelles IFPEN
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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
    • 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

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  • ABSTRACT Process for separating aromatics from hydrocarbon mixtures [containing the same] by combined extractive and azeotropic fractional distillation thereof in the presence of a liquid alkyl aliphatic amide as extraction [solvent] agent, comprising introducing said mixture at a first level of a distillation column, introducing the extraction [solvent] agent at a second level of the distillation column above the first one, introducing steam as an azeotropic agent in the distillation column above said second level, withdrawing the aromatics and the extraction [solvent] agent from the bottom of the column and the non-aromatic hydrocarbons and the steam from the top thereof.
  • the extractive agent has a higher dissolving power for the hydrocarbons and a good selectivity for the aromatics
  • the azeotropic agent has a limited dissolving power for the hydrocarbons and the property of forming an azeotropic system with at least one of the non-aromatic hydrocarbons which have to be separated.
  • These two agents also have such boiling points as to be discharged each from a different end portion of the distillation column: one from the bottom of the column with the aromatic hydrocarbons and the other at the top of the column with the non-aromatic hydrocarbons.
  • benzene and/or toluene from, for example, benzene cuts and/or toluene cuts obtained from reaction products containing ofaromatic hydrocarbons starting from saturated or unsaturated gasolines (which have been subjected to a previous partial hydrogenation, so as to limit the impurities substantially to the saturated hydrocarbons) and subjected to pyrolysis, cracking, steam cracking or catalytic reforming reactions.
  • benzene cut there is meant a mixture of benzene and hydrocarbons having a lower boiling point of at least about 65C and an upper boiling point of at most 102C.
  • this cut may consist of a mixture of benzene with saturated hydrocarbons having essentially 6 to 8 carbon atoms.
  • the invention may also be applied to benzene cuts containing lighter hydrocarbons.
  • toluene cut there is meant a mixture of toluene with saturated hydrocarbons having lower and upper boiling points of about 102C to about 120C.
  • the liquid-liquid extraction process is used when it is desired to selectively extract a relatively large number of hydrocarbons of the same chemical family, for example, benzene, toluene, xylene, ethylbenzene etc the extractive distillation is preferred when it is desired to selectively extract a more limited number of compounds of the same chemical family. for example, benzene and/or toluene.
  • the extractive agent is employed, in conjunction with an agent which preferably consists of steam (this agent being called associated solvent or azeotropic agent although it is used in the vapor form and not in the liquid form) according to a distillation procedure which will be called hereinafter extractive .azeo- I tropic distillation.
  • solvents are well known as efficient separating agents of hydrocarbons having different degrees of saturation. However, they also have the property of forming azeotropes with saturated hydrocarbons of 6,7 or 8 carbon atoms, and accordingly their use in a conventional extractive distillation for purifying benzene and- /or toluene would result in an unavoidable loss of solvent which would be carried along at the top of the column with the impurities having 6,7 or 8 carbon atoms of the benzene and/or toluene.
  • the associated solvent When proceeding according to the invention, with the associated solvent, this loss of the extraction agent is avoided. More generally, the associated solvent must have a boiling temperature lower than that of the extraction solvent, must not form an azeotrope with the latter and must, preferably, be miscible to a low extent with non-aromatic hydrocarbons of the benzene and/or toluene fractions. For example, the non-aromatic hydrocarbons must dissolve less than 1 percent and preferably less than 0.1 percent by weight of said associated solvent.
  • pure benzene and/or toluene are obtained from mixtures containing the same together with cycloparaffinic (naphthenic) or paraffinic branched or unbranched hydrocarbons, by subjecting said mixture to distillation in the presence of a solvent system consisting, on the one hand, of an extraction solvent and, on the other hand, of the associated solvent, such as defined supra.
  • a solvent system consisting, on the one hand, of an extraction solvent and, on the other hand, of the associated solvent, such as defined supra.
  • the manipulative steps of process are such that the mixture of hydrocarbons to be separated is introduced in the distillation zone, at an intermediate point thereof and the extraction solvent is introduced at a point of the distillation zone, preferably above the point of introduction of the hydrocarbon mixture, and in the associated solvent is introduced, in the vapor form, at a point in the distillation zone above the point of introduction of the extraction solvent.
  • the top product of the distillation zone or distillate is condensed and the resulting condensate is separated in two liquid phases, a first phase of which contains the non-aromatic hydrocarbons and the second phase, the associated solvent, the first and second phase being withdrawn separately, the bottom product containing aromatic hydrocarbons and the extraction solvent is discharged from said distillation zone and the solvent is separated from the aromatic hydrocarbons in a known manner, so as to obtain, on the one hand, the recovered extraction solvent, and on the other hand the aromatic hydrocarbons.
  • the efficiency of the fractionation is increased by feeding back to the distillation column, as reflux, a portion of the first condensed phase, the other portion being merely withdrawn.
  • the point of introduction of this reflux is preferably above the point of introduction of the azeotropic agent.
  • the aromatic hydrocarbons may be separated from the extraction solvent by distillation or liquid-liquid reextraction of the aromatics by means of a third solvent, such as a liquid paraffinic hydrocarbon, which can be later separated by distillation from said aromatic hydrocarbons, this being the case, for example, of liquid butane, pentane or heavy cuts such as gas-oil or kerosene.
  • a third solvent such as a liquid paraffinic hydrocarbon, which can be later separated by distillation from said aromatic hydrocarbons, this being the case, for example, of liquid butane, pentane or heavy cuts such as gas-oil or kerosene.
  • the extraction solvent vapors are substantially not carried away from the extractive distillation column.
  • the hydrocarbon mixture containing the benzene and/or toluene to be extracted is sent, preferably at a temperature close to its bubble point, through pipe 1 to column CI.
  • the organic solvent is introduced into said column through pipe 6, opening thereinto at a level above that of the initial hydrocarbon mixture, at a temperature close to that prevailing in the column at the same level under predetermined operating conditions.
  • the ratio by volume of the solvent to the hydrocarbons feed is advantageously selected from 0.4 to 15, and preferably from 1 to 6.
  • the organic solvent which is the less volatile compound, mainly flows in the liquid form towards the bottom of column CI, carrying along therewith the aromatics to which it imparts a modified volatility with respect to the paraffinic or naphthenic impurities which originally are present therewith.
  • the mixture solvent-aromatics is discharged from column CI through pipe 7 and conveyed to column CII wherefrom, by conventional distillation, the aromatics are separated at the top through line 8, the condenser 11 and line 13, and at the bottom, the regenerated solvent which is recycled to column Cl through line 6.
  • a portion of the aromatic hydrocarbons may be fed back to the colum CII through pipe 12.
  • the effluent from the bottom of column CI comprising the organic solvent and the aromatics, is sent to column CII wherefrom purified benzene is discharged at the top and the organic solvent containing the toluene, from the bottom.
  • This last mixture is sent to a column Clll, not shown, at the top of which the purified toluene is obtained and from the bottom of which the organic solvent is withdrawn and recycled to column Cl through pipe 6.
  • vaporized water is injected (through line 5 and vaporizer 9). It is convenient to make use of 5 to 50 percent, preferably, 10 to 35 percent by weight of water with respect to the nonaromatic hydrocarbons of the treated charge.
  • the amount of steam will be preferably lower than that which would lead to a water condensation in order to avoid that liquid water be admixed with the extraction solvent.
  • the water forms with the hydrocarbons present, i.e. mainly the non-aromatic ones, an azeotropic mixture which is more volatile with respect to the organic solvent than the hydrocarbons alone, which azeotropic mixture distills at the top of the column and is discharged through pipe 2.
  • This effluent is condensed in unit 10 and decanted in two liquid phases in the decanter D.
  • a portion of the upper phase, consisting of hydrocarbons, is fed back through pipe 3 to column Cl, as reflux, while the other portion is discharged from the unit through pipe 4.
  • the lower phase consisting essentially of water, may be withdrawn from the unit, or recycled to column CI through pipe 5, under the hereabove defined conditions.
  • the associated solvent is generally introduced, in the distillation column, for a particularly efficient operation of the process, at a level above the point of introduction of the selective solvent but below that of the distillate reflux.
  • a second advantage is due to the fact that the extraction solvent is not shared between the top and the bottom of the separation column: all the solvent is used for purifying the aromatics and, accordingly, for the same degree of purity, the amount of solvent to be introduced in the column is lower.
  • Another advantage is due to the fact that the associated solvent, i.e. water, facilitates the removal of the impurities from the aromatics.
  • dialkyl amides may be slightly hydrolyzed in the presence of water, in the liquid phase, at a temperature higher than 120C. According to the process of the invention, the water is in the vapor phase and the amide in the liquid phase in a zone where the temperature is about C. The only liquid phase contact between the amide and the water which might casually occur in the case of a improper operation of the apparatus, would be in the decanter where the temperature is always lower than 70C and may be selected as low as desired.
  • EXAMPLE 1 In a distillation column, 4 meters high, consisting of 3 meters of elements of the Oldershaw type having a 2.5 cm diameter and of an adiabatic element with a Dixon filling system, of the same diameter, there are injected, at the respective levels of 1m, 2.5m, and 3m from the column bottom:
  • the distillate which is recovered from the top of the column, at a temperature of 71C, is condensed and decanted in two phases: a lower phase consisting of water which is recycled to the column at the previously defined level and an upper phase whose composition is indicated in table 1, consisting essentially of nonaromatic impurities of the benzene cut, a portion of which, ie 54 g/h, is withdrawn and discharged from the system and the other portion of which is fed back to the top of the column, also at a rate of 54 g/h, as reflux.
  • Example 1 is repeated except that the amount of water introduced in example 1 as vapor, is now introduced in the liquid form, in the extractive distillation column, at the level where, in example 1, water was injected in the form of steam.
  • Example 1 is repeated, while introducing the indicated water amounts in the liquid form, not in the column itself, but in the pipe between the top of the column and the condenser of the vapors issued from said column.
  • the upper phase of the distillate contained more than 1 percent of the extraction solvent, which is contrary to the desired result and makes necessary, after a long working period, a distillation for recovering the solvent carried away from the column.
  • EXAMPLE 1C EXAMPLE 2 In the same column as that described in the example 1, there are introduced, at the respective levels of 1m, 2.5m and 3m from the column bottom:
  • the water and the non-aromatic hydrocarbons are recovered at the top of the column where the prevailing temperature is 75C, and they are condensed and separated by decantation in two phases.
  • the lower phase consisting of water, is recycled to the column after vaporization while a portion (33.2g) of the upper phase is withdrawn from the system and the other portion (33 g) is recycled to the top of the column as reflux.
  • the composition of the withdrawn hydrocarbon phase is given in table Ill, column 2.
  • hydrocarbons in admixture with said at least one aromatic hydrocarbon are saturated hydrocarbons having from 5 to 8 carbon atoms per molecule.
  • a process according to claim 1, in which said mixtures subjected to extractive azeotropic distillation are gasolines produced by pyrolysis, cracking, steam cracking or catalytic reforming.
  • a process according to claim 9, comprising a further step of separating the aromatic hydrocarbons from the extraction solvent by distillation.

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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)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
US343108A 1972-03-20 1973-03-20 Process for purifying benzene and toluene by extractive azeotropic distillation Expired - Lifetime US3884769A (en)

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US (1) US3884769A (enrdf_load_stackoverflow)
JP (1) JPS5632971B2 (enrdf_load_stackoverflow)
BE (1) BE796434A (enrdf_load_stackoverflow)
CA (1) CA988451A (enrdf_load_stackoverflow)
DD (1) DD104501A1 (enrdf_load_stackoverflow)
DE (1) DE2313603C2 (enrdf_load_stackoverflow)
FR (1) FR2176488B1 (enrdf_load_stackoverflow)
GB (1) GB1430481A (enrdf_load_stackoverflow)
IT (1) IT981410B (enrdf_load_stackoverflow)
NL (1) NL7303911A (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4168209A (en) * 1977-03-08 1979-09-18 Institut Francais Du Petrole Process for purifying benzene and toluene by extractive azeotropic distillation
US4514262A (en) * 1982-08-02 1985-04-30 Lloyd Berg Separation of benzene from non-aromatic hydrocarbons by extractive distillation
US4569647A (en) * 1983-09-16 1986-02-11 Pelam, Inc. Apparatus for preparing and embedding tissue samples for histological examination
US4955468A (en) * 1989-09-08 1990-09-11 Phillips Petroleum Company Separation of hydrocarbon mixtures
US5068011A (en) * 1990-10-26 1991-11-26 Phillips Petroleum Company Separation of monoolefins from paraffins
US5399244A (en) * 1993-12-06 1995-03-21 Glitsch, Inc. Process to recover benzene from mixed hydrocarbons by extractive distillation
US5458741A (en) * 1994-01-14 1995-10-17 Lloyd Berg Separation of benzene from close boiling hydrocarbons by extractive distillation
US5723026A (en) * 1994-10-21 1998-03-03 Krupp Koppers Gmbh Process for recovering pure benzene and pure toluene from aromatic hydrocarbon products
RU2291849C1 (ru) * 2005-11-03 2007-01-20 Открытое акционерное общество "Нижнекамскнефтехим" Способ выделения бензола
US20080128264A1 (en) * 2006-08-09 2008-06-05 Kuang Yeu Wu Three-phase extractive distillation with multiple columns connected in series
US20100270213A1 (en) * 2009-04-28 2010-10-28 Noe Robert J L Extractive distillation process and system
CN102068831A (zh) * 2010-12-15 2011-05-25 天津大学 乙腈-甲醇共沸混合物的间歇萃取精馏装置和分离方法
US9284237B2 (en) 2013-12-13 2016-03-15 Uop Llc Methods and apparatuses for processing hydrocarbons
CN109912375A (zh) * 2017-12-13 2019-06-21 北京英斯派克科技有限公司 一种甲苯不溶物实验装置和甲苯回收方法
CN111635425A (zh) * 2020-07-07 2020-09-08 山东中盛药化设备有限公司 一种用于分离甲苯和硅醚的方法及系统

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7802444A (nl) * 1977-03-08 1978-09-12 Inst Francais Du Petrole Werkwijze voor de zuivering van benzeen en tolu- een door extractieve azeotrope -destillatie.
FR2388580A1 (fr) * 1977-04-29 1978-11-24 Inst Francais Du Petrole Procede et dispositif de controle d'une distillation extractive
RU2287514C1 (ru) * 2005-08-05 2006-11-20 Открытое акционерное общество Научно-исследовательский институт "Ярсинтез" (ОАО НИИ "Ярсинтез") Способ получения бензола и дебензолированной высокооктановой смеси
CN104718276B (zh) * 2012-08-09 2017-08-25 科学工业研究委员会 用于通过从含有机过氧化物的未加工的裂化汽油馏分回收高纯度苯来制备贫苯汽油的方法

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2804427A (en) * 1955-10-27 1957-08-27 Jack F Suriano Method and apparatus for deodorizing oils and fats
US2859155A (en) * 1955-12-27 1958-11-04 Du Pont Process for vaporizing hydrogen peroxide by connective distillation
US2957811A (en) * 1957-11-05 1960-10-25 Universal Oil Prod Co Segregation of xylene isomers
US3114783A (en) * 1959-08-27 1963-12-17 Exxon Research Engineering Co Separation of aromatics from hydrocarbon streams
US3151046A (en) * 1959-05-22 1964-09-29 Phillips Petroleum Co Methylethylpyridine-methylvinylpyridine fractionation
US3328267A (en) * 1963-03-12 1967-06-27 Erdoelchemie Gmbh Separation of o-xylene and styrene by distillation with a dialkylformamide
US3684665A (en) * 1969-02-17 1972-08-15 Toray Industries Process for recovering styrene and xylenes from cracked oil by extractive distillation with a dealkyl acetamide

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD82908A (enrdf_load_stackoverflow) *

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2804427A (en) * 1955-10-27 1957-08-27 Jack F Suriano Method and apparatus for deodorizing oils and fats
US2859155A (en) * 1955-12-27 1958-11-04 Du Pont Process for vaporizing hydrogen peroxide by connective distillation
US2957811A (en) * 1957-11-05 1960-10-25 Universal Oil Prod Co Segregation of xylene isomers
US3151046A (en) * 1959-05-22 1964-09-29 Phillips Petroleum Co Methylethylpyridine-methylvinylpyridine fractionation
US3114783A (en) * 1959-08-27 1963-12-17 Exxon Research Engineering Co Separation of aromatics from hydrocarbon streams
US3328267A (en) * 1963-03-12 1967-06-27 Erdoelchemie Gmbh Separation of o-xylene and styrene by distillation with a dialkylformamide
US3684665A (en) * 1969-02-17 1972-08-15 Toray Industries Process for recovering styrene and xylenes from cracked oil by extractive distillation with a dealkyl acetamide

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4168209A (en) * 1977-03-08 1979-09-18 Institut Francais Du Petrole Process for purifying benzene and toluene by extractive azeotropic distillation
US4514262A (en) * 1982-08-02 1985-04-30 Lloyd Berg Separation of benzene from non-aromatic hydrocarbons by extractive distillation
US4569647A (en) * 1983-09-16 1986-02-11 Pelam, Inc. Apparatus for preparing and embedding tissue samples for histological examination
US4955468A (en) * 1989-09-08 1990-09-11 Phillips Petroleum Company Separation of hydrocarbon mixtures
US5068011A (en) * 1990-10-26 1991-11-26 Phillips Petroleum Company Separation of monoolefins from paraffins
US5399244A (en) * 1993-12-06 1995-03-21 Glitsch, Inc. Process to recover benzene from mixed hydrocarbons by extractive distillation
US5458741A (en) * 1994-01-14 1995-10-17 Lloyd Berg Separation of benzene from close boiling hydrocarbons by extractive distillation
US5723026A (en) * 1994-10-21 1998-03-03 Krupp Koppers Gmbh Process for recovering pure benzene and pure toluene from aromatic hydrocarbon products
RU2291849C1 (ru) * 2005-11-03 2007-01-20 Открытое акционерное общество "Нижнекамскнефтехим" Способ выделения бензола
US20080128264A1 (en) * 2006-08-09 2008-06-05 Kuang Yeu Wu Three-phase extractive distillation with multiple columns connected in series
US20100270213A1 (en) * 2009-04-28 2010-10-28 Noe Robert J L Extractive distillation process and system
US8282816B2 (en) 2009-04-28 2012-10-09 Uop Llc Extractive distillation process and system
CN102068831A (zh) * 2010-12-15 2011-05-25 天津大学 乙腈-甲醇共沸混合物的间歇萃取精馏装置和分离方法
CN102068831B (zh) * 2010-12-15 2012-11-21 天津大学 乙腈-甲醇共沸混合物的间歇萃取精馏装置和分离方法
US9284237B2 (en) 2013-12-13 2016-03-15 Uop Llc Methods and apparatuses for processing hydrocarbons
CN109912375A (zh) * 2017-12-13 2019-06-21 北京英斯派克科技有限公司 一种甲苯不溶物实验装置和甲苯回收方法
CN111635425A (zh) * 2020-07-07 2020-09-08 山东中盛药化设备有限公司 一种用于分离甲苯和硅醚的方法及系统
CN111635425B (zh) * 2020-07-07 2022-12-20 山东中盛药化设备有限公司 一种用于分离甲苯和硅醚的方法及系统

Also Published As

Publication number Publication date
IT981410B (it) 1974-10-10
FR2176488A1 (enrdf_load_stackoverflow) 1973-11-02
JPS495925A (enrdf_load_stackoverflow) 1974-01-19
FR2176488B1 (enrdf_load_stackoverflow) 1975-03-21
GB1430481A (en) 1976-03-31
DE2313603A1 (de) 1973-09-27
DD104501A1 (enrdf_load_stackoverflow) 1974-03-12
JPS5632971B2 (enrdf_load_stackoverflow) 1981-07-31
DE2313603C2 (de) 1982-04-15
CA988451A (fr) 1976-05-04
BE796434A (fr) 1973-09-10
NL7303911A (enrdf_load_stackoverflow) 1973-09-24

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