US3720605A - Process for the extraction of aromatic hydrocarbons by keto and aldo-morpholines - Google Patents

Process for the extraction of aromatic hydrocarbons by keto and aldo-morpholines Download PDF

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Publication number
US3720605A
US3720605A US00055908A US3720605DA US3720605A US 3720605 A US3720605 A US 3720605A US 00055908 A US00055908 A US 00055908A US 3720605D A US3720605D A US 3720605DA US 3720605 A US3720605 A US 3720605A
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stage
solvent
fraction
overhead
extract
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US00055908A
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G Paret
E Cinelli
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SnamProgetti SpA
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SnamProgetti SpA
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D11/00—Solvent extraction
    • B01D11/04—Solvent extraction of solutions which are liquid
    • B01D11/0488—Flow sheets
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/005—Processes comprising at least two steps in series
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00—Purification; Separation; Use of additives
    • C07C7/10—Purification; Separation; Use of additives by extraction, i.e. purification or separation of liquid hydrocarbons with the aid of liquids

Definitions

  • the process according to the present invention relates to an improved process for the extraction of aromatic hydrocarbons by using a well defined class of solvents selected from keto and aldomorpholines.
  • Said processes make use of solvents which selectively dissolve aromatic hydrocarbons.
  • the first stage consists in contacting the feed mix ture with the solvent, generally in a countercurrent contact system.
  • the two streams obtained are a raffinate with a very low contentof aromatic hydrocarbons and an extract containing practically all the aromatic hydrocarbons present in the feed mixture;
  • the second stage again a liquid-liquid extraction, consists in contacting in countercurrent relation the extract of the first stage with the overhead products of the third stage.
  • This contact is realized with the purpose of removing the heavier non-aromatic hydrocarbons present in the extract of the first stage and coming from the feed mixture.
  • the two streamscoming from the second stage are a light one, sent to the first stage, and a bottom product sent to the third stage.
  • this bottom product is constituted by solvent, aromatic'hydrocarbons and saturated hydrocarbons too.
  • Said saturated hydrocarbons are not the same present in the extract of the first stage either as composition or generally as amount.
  • a solvent is selected that presents a good selectivity between aromatic and nonaromatic hydrocarbons and at the same time a good selectivity for lower boiling homologous hydrocarbons having different numbers of carbon atoms.
  • the third stage consists in an extractive distillation for the extract coming from the second stage.
  • This overhead stream is refluxed to the second stage, while the bottom product of the extractive distillation consists of solvent and of aromatics, the latter already at the desired purity.
  • the fourth stage consists in a distillation of the bottom product coming from the third stage. In this way aromatics are obtained as overhead and solvent-as bottom product.
  • the first and second stages may be carried out in a single apparatus.
  • the third and fourth stages are on the contrary preferably carried out in different apparatuses.
  • the overhead from the third stage, to be sent to the second stage is rectified in absence of solvent (see FIG. 2).
  • the heavier products containing saturated hydrocarbons having high boiling points and non-aromatic hydrocarbons having a very high polarity as some hydrocarbons in the class of naphthenes, biand polycyclic naphthenes, olephines, cyclo-olephines and derived compounds are obtained.
  • As overhead products saturated and light aromatic hydrocarbons are obtained and sent to the second stage, while the bottom may be drained or sent to suitable points of the extraction cycle, so as to avoid its accumulation into the cycle.
  • Said stream, i.e. the bottom may be introduced into the first stage between the feed inlet and the solvent inlet. Said separation is possible also, in the easiest cases, by condensation at two different thermal levels, refluxing to the second stage the condensate coming from the lower thermal level.
  • the overhead of the third and fourth stages contains large amount of water.
  • the water contained in the overhead of the third stage is sent, as it is, to the second stage, according to known techniques.
  • said water is divided in four variable streams depending on the operative conditions and it is utilized as follows (see FIG. 3).
  • One stream is refluxed to the top of the stripper, i.e. fourth stage, with the advantage of washing the rising vapors and of avoiding the presence of solvent in the overhead.
  • a second stream is recycled to the second stage, while a third stream is utilized to wash the rafflnate and then is mixed with the preceding stream.
  • the remaining water is vaporized by indirect heat exchange with the lean solvent coming from the bottom of the fourth stage and is introduced at the bottom of the stripper, i.e. the fourth stage.
  • the aldehydic and ketonic derivatives of morpholine and particularly the N-formyl morpholine with water content up to 30 percent by weight are particularly efficient, though any other solvent presenting a good selectivity and transport capacity for the aromatics may be utilized in the described process.
  • the temperature in the extraction operations of the first and second stages ranges from C and 90C while in the distillation operations of the third and fourth stages is ranges from 50C and 200 C.
  • Said expedients consist mainly in an accurate removing of the oxygen and in the use of suitable inhibitors.
  • the raffinate leaves the extractor from the top through line 4 and is fed to the bottom of the washing column 5 where, to the top, water is fed through 6. From the top the raffinate leaves the column 5 through 7 while from the bottom, through line 8, the washing water containing traces of solvent before present in the raffinate leaves the same column.
  • Said stream in the present case, consists of water, light aliphatic hydrocarbons and the lightest aromatics.
  • the selective function of the solvent allows one to obtain as overhead product, through line 18, all the non-aromatic hydrocarbon compounds together with a part of the present lighter aromatics.
  • Said stream is condensed and sent to the column 19 where a rectification is effected and an overhead is separated, withdrawn through 20 and reused in closed loop.
  • Said stream, through line 22, is fed to the column 23 where the separation of the hydrocarbons from the solvent is carried out.
  • the lean solvent is withdrawn from the bottom through line 24, sent to the exchanger 25 where most of its sensible heat content is recovered, and then the solvent is reused in the extraction.
  • water is refluxed through 26 so as to obtain an overhead product without solvent.
  • Part of this water is refluxed to the column 23 through 26, while another part is sent as washing agent to the column 5 through line 6.
  • the remaining water is divided and one part is fed, through 31, to the exchanger 25 and sent vaporized to the bottom of column 23.
  • the remainder is mixed through line 32, with the streams of lines 20, 14, 8 and enters, as purification agent, the extractor through 11.
  • Said feed was sent to the 24th tray of the liquid-liquid extraction column 1, provided with 60 perforated trays, at a flow rate of 5 kg/hr. .To the top of column 1 as solvent for formyl morpholine at 5% b.w. of water was fed, at a flow rate of 15kg/hr; to the bottom of the column 1 the lighter fraction of the column 2 overhead was fed, at a flow rate of 1.8 kg/hr with 0.7 kg of water; the heavier fraction of the overhead of column 2 condensed at temperature higher than 120C. at a flow rate of 0.2 kg/hr was mixed with the feed.
  • the column operated at temperature ranging from and C.
  • the extract flowing out from the extractor 1 was heated to 80C and fed to the head tray of the column 2 provided with 27 trays, operating without reflux; the
  • bottom temperature of column 2 was kept at 120C and the overhead condensed at two different temperatures in the condensers 3 and 4; in the condenser 3 0.2 kg of hydrocarbons are condensed, in the condenser 4 1.8 kg.
  • the enriched solvent flowing out from the bottom of the column 2 was sent to the next distillation column 5, provided with 22 trays, where at the top pure aromatics with 2.2 kg/hr of water and at the bottom the solvent containing 5% b.w. of water were obtained; to the bottom of column 5, operating at 152C, steam was fed at a rate of 1.5 kg/hr.
  • the non-aromatics content was of 800 ppm.
  • a process for the extraction of aromatic hydrocarbons corn rising a first stage of solvent extraction wherein t e feed mixture 15 contacted with solvent selected from the group consisting of anhydrous and aqueous ketonic and aldehydic derivatives of morpholine and with a low boiling fraction of hydrocarbons coming from a subsequent stage in a multi-stage system in countercurrent, a second stage of purification of the extract of the first stage by solvent extraction wherein said first stage extract is contacted in countercurrent with a hydrocarbon fraction coming at least in part from a subsequent third stage of extractive distillation, a third stage of extractive distillation of the extract, coming from the second stage, which gives an overhead to be utilized in the second stage as purification agent and finally a fourth stage of rectification of the bottom of the third stage so as to separate the aromatics from said solvent which is then recycled to the first stage characterized in the combination of at least two of the following steps consisting in:
  • a process according to claim 1 characterized in that the separation of the low boiling fraction of the overhead from the third stage of extractive distillation is carried out by rectification in absence of solvent.
  • a process according to claim 1 characterized in that the separation of the low boiling fraction of the overhead coming from the third stage of extractive distillation is carried out by condensation in two or more stages.
  • a process according to claim 1 characterized in that a low boiling aliphatic fraction is added to the reflux fraction of the second stage of extract purification.
  • a process according to claim 1 characterized in that an aqueous stream is added to the reflux fraction of the second stage of purification.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
US00055908A 1969-07-18 1970-07-17 Process for the extraction of aromatic hydrocarbons by keto and aldo-morpholines Expired - Lifetime US3720605A (en)

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IT1981269 1969-07-18

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US3720605A true US3720605A (en) 1973-03-13

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US (1) US3720605A (de)
JP (1) JPS4924901B1 (de)
AT (1) AT312138B (de)
BE (1) BE753353A (de)
BG (1) BG25642A3 (de)
CA (1) CA955875A (de)
CS (1) CS167923B2 (de)
DE (3) DE2035315C3 (de)
DK (1) DK131511B (de)
ES (1) ES381945A1 (de)
FR (1) FR2051835B1 (de)
GB (1) GB1271596A (de)
LU (1) LU61349A1 (de)
NL (1) NL167143C (de)
RO (1) RO61637A (de)
SU (1) SU365071A3 (de)
YU (1) YU35748B (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
US4081355A (en) * 1970-08-12 1978-03-28 Krupp-Koppers Gmbh Process for recovering highly pure aromatics from a mixture of aromatics and non-aromatics
US6375802B1 (en) * 1997-09-03 2002-04-23 Hfm International, Inc. Method of retrofitting existing equipment for an improved aromatics separation process
US20110200572A1 (en) * 2010-02-17 2011-08-18 Osprey Biotechnics, Inc. Compositions for stabilizing bacillus spores and methods of use thereof
US8471088B2 (en) 2011-01-31 2013-06-25 Exxonmobil Chemical Patents Inc. Solvent quality control in extraction processes
US9138658B2 (en) 2011-01-31 2015-09-22 Exxonmobil Chemical Patents Inc. Solvent quality control in extraction processes
EP2882830B1 (de) * 2012-08-09 2018-01-03 Council of Scientific & Industrial Research Verfahren zur herstellung von benzin mit geringem benzolgehalt durch rückgewinnung von hochreinem benzol aus unbehandelten krackbenzinfraktionen mit organischen peroxiden

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8460517B2 (en) * 2009-09-02 2013-06-11 Gtc Technology Us Llc Methods and apparatuses for steam addition to a reboiler coupled to an extractive distillation column for improved extractive distillation

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3262875A (en) * 1961-06-07 1966-07-26 Snam Societa Per Azioni Process for extracting high-purity aromatic hydrocarbons from a hydrocarbonaceous mixture
US3325399A (en) * 1964-10-14 1967-06-13 Snam Spa Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same
US3487013A (en) * 1968-02-26 1969-12-30 Universal Oil Prod Co Solvent extraction with recycle of light nonaromatic fraction
US3551327A (en) * 1969-03-12 1970-12-29 Universal Oil Prod Co Extractive distillation of aromatics with a sulfolane solvent
US3558480A (en) * 1968-10-28 1971-01-26 Universal Oil Prod Co Light and heavy reflux streams in solvent extraction of aromatics

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3262875A (en) * 1961-06-07 1966-07-26 Snam Societa Per Azioni Process for extracting high-purity aromatic hydrocarbons from a hydrocarbonaceous mixture
US3325399A (en) * 1964-10-14 1967-06-13 Snam Spa Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same
US3487013A (en) * 1968-02-26 1969-12-30 Universal Oil Prod Co Solvent extraction with recycle of light nonaromatic fraction
US3558480A (en) * 1968-10-28 1971-01-26 Universal Oil Prod Co Light and heavy reflux streams in solvent extraction of aromatics
US3551327A (en) * 1969-03-12 1970-12-29 Universal Oil Prod Co Extractive distillation of aromatics with a sulfolane solvent

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4081355A (en) * 1970-08-12 1978-03-28 Krupp-Koppers Gmbh Process for recovering highly pure aromatics from a mixture of aromatics and non-aromatics
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
US6375802B1 (en) * 1997-09-03 2002-04-23 Hfm International, Inc. Method of retrofitting existing equipment for an improved aromatics separation process
US20110200572A1 (en) * 2010-02-17 2011-08-18 Osprey Biotechnics, Inc. Compositions for stabilizing bacillus spores and methods of use thereof
US8471088B2 (en) 2011-01-31 2013-06-25 Exxonmobil Chemical Patents Inc. Solvent quality control in extraction processes
US9138658B2 (en) 2011-01-31 2015-09-22 Exxonmobil Chemical Patents Inc. Solvent quality control in extraction processes
EP2882830B1 (de) * 2012-08-09 2018-01-03 Council of Scientific & Industrial Research Verfahren zur herstellung von benzin mit geringem benzolgehalt durch rückgewinnung von hochreinem benzol aus unbehandelten krackbenzinfraktionen mit organischen peroxiden

Also Published As

Publication number Publication date
BG25642A3 (de) 1978-11-10
FR2051835A1 (de) 1971-04-09
SU365071A3 (de) 1972-12-28
DE2035315A1 (de) 1971-05-19
NL7010676A (de) 1971-01-20
LU61349A1 (de) 1970-09-16
YU35748B (en) 1981-06-30
ES381945A1 (es) 1972-12-01
NL167143C (nl) 1981-11-16
FR2051835B1 (de) 1973-04-27
GB1271596A (en) 1972-04-19
AT312138B (de) 1973-12-27
CA955875A (en) 1974-10-08
DE2065780B2 (de) 1978-12-14
DE2035315C3 (de) 1979-02-01
RO61637A (de) 1977-02-15
YU165570A (en) 1980-10-31
DE2065779B2 (de) 1979-01-04
DK131511B (da) 1975-07-28
NL167143B (nl) 1981-06-16
DE2065780C3 (de) 1979-08-23
DE2065779C3 (de) 1979-08-30
CS167923B2 (de) 1976-05-28
DE2065780A1 (de) 1975-09-11
JPS4924901B1 (de) 1974-06-26
DE2035315B2 (de) 1977-04-28
DK131511C (de) 1975-12-22
DE2065779A1 (de) 1975-09-18
BE753353A (fr) 1970-12-16

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