US3325399A - Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same - Google Patents

Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same Download PDF

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Publication number
US3325399A
US3325399A US493850A US49385065A US3325399A US 3325399 A US3325399 A US 3325399A US 493850 A US493850 A US 493850A US 49385065 A US49385065 A US 49385065A US 3325399 A US3325399 A US 3325399A
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Prior art keywords
solvent
aromatic
aromatic hydrocarbons
extract
hydrocarbons
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US493850A
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English (en)
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Cinelli Ermanno
Girotti Pierleone
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Snam SpA
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Snam SpA
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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
    • 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
    • C10G21/02—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents with two or more solvents, which are introduced or withdrawn separately
    • C10G21/04—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents with two or more solvents, which are introduced or withdrawn separately by introducing simultaneously at least two immiscible solvents counter-current to each other

Definitions

  • This invention relates to a process for the separation of aromatic hydrocarbons from hydrocarbonaceous mixtures by solvent extraction, which is eflicient both in the treatment of low-boiling and of high-boiling hydrocarbonaceous fractions.
  • the prior art disclosed many processes for the ext-raction with solvent of aromatic hydrocarbons from hydrocarbonaceous fractions. According to these processes, the extract consisting of the solvent and the aromatic hydrocarbon contained therein is distilled so as to regenerate the solvent while recovering the aromatic compound.
  • An object of the present invention is to provide a process for the extraction of aromatic hydrocarbons which can be readily applied even when the boiling points of the hydrocarbons and of the solvent present in the extract are near to one another.
  • formylmorpholine both in its anhydrous and hydrated form, exhibits a corrosive action towards the conventional materials and is rapidly altered in the presence of ferrous products of the corrosion.
  • An object of the present invention is to provide a process which uses the satisfactory solvent characteristics of formylmorpholine in spite of the aforementioned shortcomings. It is thus compulsory that formylmorpholine be employed, in each and every stage of the process run, at temperatures under 90 C.
  • the foregoing objects are achieved by a process which comprises the following steps:
  • a solvent which essentially consists of formylmorpholine
  • feeding the stock at one or more intermediate points of said system feeding a non-aromatic reflux, having a boiling point lower than that of said stock, at the end of the system which is opposite to the solvent feed-in point, distilling off from the refined stock the lightweight fraction coming from the non-aromatic reflux, washing the extract in counter-flow with a non-aromatic hydrocarbonaceous fraction having a boiling point lower than that of the aromatics contained in the extract and discharging, from one side a stream consisting of virtually aromatic-free regenerated solvent and, from the other side, a stream formed by the hydrocarbons retained by the extract and by the non-aromatic hydrocarbonaceous washings.
  • Said stream is sent to the distillation system to remove the fraction employed for the washing step from the extracted hydrocarbons.
  • the temperature is maintained between 20 C. and 90 C., the 25 C. C. range being preferred, i.e. in the stability and non-corrosiveness field of formylmorpholine.
  • the treatment of the extracted fraction consists of a distillation of the non-aromatic lightweight fraction which is utilized as the washing and refluxing agent, and of a subsequent distillation, from the tailings of the previous distillation step, of a fraction which is recycled to the extraction as stock and is formed by a fraction of the more volatile hydrocarbon along with the small amount of possibly present non-aromatics.
  • the final product essentially consists of aromatic hydrocarbons.
  • the ratio by volume of the solvent to the fed-in stock ranges between 1 to 1 and 5 to 1, and preferably lies between 2:1 and 3.5: 1. Even with so low values as compared with those of the known methods, it is possible to recover aromatics with yields over 96% and with a nitration grade purity.
  • the reflux to stock ratio is slightly lower.
  • the very high selectivity towards aromatics along with the very low solvent power for non-aromatics as shown by formylmorpholine which on the other hand displays a preferential solubility for the lightweight non-aromatics with respect to the heavier ones, acts in such a way that a reflux of low-boiling non-aromatics, preferably paraflins, is more advisable. It has been found that the volume ratios of non-aromatic refluxes to fresh stock as fed are fit to the purpose according to an unexpectedly low rating, i.e. between 0.15 to 1 and 0.7 to 1; and preferably between 0.25 to 1 and 0.5 to 1.
  • Said fraction is not used for refluxing, in that the aromatics which are present would not give rise to an advantage for said operation, but is fed-in at the extraction stage as a stock, i.e. in the stage in which the hydrooarbonaceous fraction which is present has a composition which is near that of the stream to be fed-in, not to trouble the extraction conditions or to cause the undesirable solubilization of the phases at the equilibrium, either.
  • the extract-washing step for recovering, on the one side, the solvent and, on the other side the aromatic hydrocarbons, has proven to have a surprising efficiency; the ratio of the nonaromatic lightweight fraction employed for the washing, to the amount of the solvent introduced at the extraction stage lies between 0.5 to 1 and 1.2 to 1 in order that a virtually total recovery of the aromatic hydrocarbons be obtained.
  • a washing carried out in a system comprised of 6 to 10 stages permits the obtention of a solvent having an aromatics con-tent of less than 1% by weight and a content of non-aromatic lightweight washings of less than 2% by weight.
  • One of the advantages of the present invention lies in that the extraction of the aromatic fraction and the separate recovery of the solvent and of the hydrocarbon of the extract are carried out without heat waste and with simple implementation. Very satisfactory results are obtained with a few stages of conventional counterflow contact columns.
  • formylmorpholine has proven to be extremely stable and noncorrosive and, under these respects, it has proven equal to the conventional solvent fluids.
  • An extraction system 1 is charged with the solvent, consisting of anhydrous formylmorpholine, via the conduit 2, with the fresh stock, consisting of a 60 C.- C. aromatic-containing fraction, via the conduit 3, with a recycling feed formed by a C fraction through the conduit 4, with a non-aromatic reflux having a boiling point lower than 60 C. and essentially consisting of a C fraction through the conduit 5.
  • the refined stock is discharged through the conduit 6 and, from the lower end the extract is discharged via the conduit 7.
  • the refined stock is then introduced in the washing systern 8 wherein, through the conduit 9, water is fed in.
  • the traces of formylmorpholine contained in the refined stock are removed in the form of a very diluted aqueous solution which is discharged via the conduit 10, whereas the solvent-freed refined stock is forwarded to the conduit 11.
  • the solvent-free refined stock is sent to the column 12 wherein a fraction, boiling under 60 C., is distilled off the refined stock, i.e. the fraction appertaining to the lowboiling nonaromatic reflux. Said fraction is removed via the conduit 13, whereas the bottoms form the final refined stock which is sent out via the conduit 14.
  • the extract, discharged with the conduit 7, is introduced in the washing system 15 wherein, via the conduit 16, a lightweight non-aromatic fraction whose boiling point is under 60 C., is also introduced.
  • the two fed-in streams are counterflown with respect to one another with an exchange of materials and two streams are discharged, the lightest one forming the solvent-free extract containing the extracted hydrocarbons and the hydrocarbonaceous washing fraction which is discharged via the conduit 17, the heavier one consisting of formylmorpholine with a small amount of hydrocarbons which is discharged via the conduit 18.
  • the solvent-free extract is then introduced, via the duct 17, into the washing system 19 wherein the formylmorpholine traces which are possibly present are washed with water having a low content of formylmorpholine which is coming through the conduit 10.
  • the washing system 19 thus discharges two streams, the
  • the non-aromatic fraction to be used for refluxing and washing could be a heptane fraction.
  • dlstlls at C s 100 for which the reflux and the washing fractlon are respono dlstlls at C 106 slble is fed into the column 28 via the duct 27.
  • distils at o C 112 In said column 28 is distilled a head fraction which, via 3 distils at I, 119 the conduit 4, is sent back to the ex r ion st ge as a disms at "s 126 recycle d consists of a slight non-aromatic fraction 3 dlstlls at C 133 whlch ls present 1n the extract and ln a portlon of the distfls at o C 139 more volatile aromatic hydrocarbon.
  • the bott m pr c End o 144 essentially contains aromatic hydrocar ons nly nd 1s 35 fl; 1 discharged i 29 and sent to an aromatic-fractionation "Percen Recovery do 99 stage (not shown).
  • any kind of hydrocarbonaceous stock containing an By employing a process with an anhydrous solvent aromatic fraction can be treated according to the invenslrnllar to that described in the diagram of the accomtive process in order to recover aromatics.
  • the extract washing column comprises Z of aromatics and more particularly the reforming prodstages, and operating at an extraction and washing temucts which have a notable content of aromatic hydroperature of 25 C., the results tabulated in Table l have carbons. been obtained.
  • the volume ratio as employed, of solvent is characterized by its possibility 45 to stock is 2.5 to 1, the employed ratio of light-Weight of being employed for the whole set of aromatic hydro-, non-aromatic washing fraction to solvent is 0.9 to 1; the carbons, from benzene to naphthalene, in that the boiling ratio of refluxing agent to fresh stock is 0.4 to 1; the ratio point of the solvent is immaterial to the end of putting of recycle to fresh stock is 0.1 to 1. the process into actual practice.
  • the refluxing and washing fraction essentially consists While the process is being progressively applied to the 50 of pentane, heavier fractions, also the non-aromatic fraction em-
  • the rates of flow and the compositions shown in Table ployed for refluxing and washing can be displaced towards 1 are by volume and refer, each, to the reference numerals the heavier members: for example, if the lowest boiling of the flow diagram shown in the accompanying drawing, aromatic to be extracted is benzene, the non-aromatic said numerals being shown at the head of the table.
  • EXAMPLE 2 The same stock of the preceding example has been treated with an aqueous solvent, still maintaining a temperature of 25 C. in the extraction and washing stages.
  • EXAMPLE 3 The raw stock employed is a cut 63 103 C. of a catalytic reforming gasoline having the following specifications:
  • a process for obtaining aromatic hydrocarbons from mixtures of aromatic hydrocarbons and non-aromatic hydrocarbons by extraction with a solvent characterized in that it comprises the steps of: introducing the hydrocarbonaceous mixture in an intermediate point of a counterflow extraction system and introducing at one end of said extraction system a solvent essentially consisting of formylmorpholine and, from the opposite end, a refluxing agent essentially consisting of a light paraflin fraction having a boiling point substantially lower than that of the hydrocarbons contained in the hydrocarbonaceous mixture, while maintaining the phases in mutual contact at a temperature between C.
  • volume ratio of the solvent to the fed-in stock is between 1 to 1 and 5 to 1.
  • volume ratio of the feed stock and the non-aromatic reflux at the extraction stage is between 0.15 to 1 and 0.7 to 1.

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  • Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Extraction Or Liquid Replacement (AREA)
US493850A 1964-10-14 1965-10-07 Process for extracting aromatic hydrocarbons from hydrocarbon mixtures containing same Expired - Lifetime US3325399A (en)

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Application Number Priority Date Filing Date Title
IT2205964 1964-10-14

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US3325399A true US3325399A (en) 1967-06-13

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US (1) US3325399A (de)
BE (1) BE670865A (de)
CS (1) CS167866B2 (de)
DE (1) DE1545365C3 (de)
DK (1) DK126860B (de)
ES (1) ES318437A1 (de)
GB (1) GB1119292A (de)
LU (1) LU49626A1 (de)
NL (1) NL6513214A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3434936A (en) * 1966-12-19 1969-03-25 Koppers Gmbh Heinrich Method of separating aromatic compounds from hydrocarbon mixtures containing the same by extractive distillation with an n-substituted morpholine
US3720605A (en) * 1969-07-18 1973-03-13 Snam Progetti Process for the extraction of aromatic hydrocarbons by keto and aldo-morpholines
US4191615A (en) * 1974-12-17 1980-03-04 Krupp-Koppers Gmbh Process for operating extraction or extractive distillation _apparatus
US4306945A (en) * 1977-08-09 1981-12-22 Snamprogetti, S.P.A. Extracting aromatic hydrocarbons from mixtures containing same
US20100305382A1 (en) * 2007-09-28 2010-12-02 Basf Se Method for obtaining aromatic hydrocarbons from a hydrocarbon mixture

Families Citing this family (2)

* 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
JP6138938B2 (ja) * 2012-08-09 2017-05-31 カウンシル オブ サイエンティフィック アンド インダストリアル リサーチ 有機ペルオキシドを含有する未処理の分解ガソリン留分から高純度ベンゼンを回収することにより低ベンゼンガソリンを製造する処理工程

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2357667A (en) * 1943-03-27 1944-09-05 Texas Co Solvent extraction
US3177196A (en) * 1960-11-25 1965-04-06 York Process Equipment Corp Liquid-liquid extraction procedure
US3186937A (en) * 1962-03-06 1965-06-01 Union Carbide Corp Separation of aromatic hydrocarbons from nonaromatic hydrocarbons

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2357667A (en) * 1943-03-27 1944-09-05 Texas Co Solvent extraction
US3177196A (en) * 1960-11-25 1965-04-06 York Process Equipment Corp Liquid-liquid extraction procedure
US3186937A (en) * 1962-03-06 1965-06-01 Union Carbide Corp Separation of aromatic hydrocarbons from nonaromatic hydrocarbons

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3434936A (en) * 1966-12-19 1969-03-25 Koppers Gmbh Heinrich Method of separating aromatic compounds from hydrocarbon mixtures containing the same by extractive distillation with an n-substituted morpholine
US3720605A (en) * 1969-07-18 1973-03-13 Snam Progetti Process for the extraction of aromatic hydrocarbons by keto and aldo-morpholines
US4191615A (en) * 1974-12-17 1980-03-04 Krupp-Koppers Gmbh Process for operating extraction or extractive distillation _apparatus
US4306945A (en) * 1977-08-09 1981-12-22 Snamprogetti, S.P.A. Extracting aromatic hydrocarbons from mixtures containing same
US20100305382A1 (en) * 2007-09-28 2010-12-02 Basf Se Method for obtaining aromatic hydrocarbons from a hydrocarbon mixture
US8362314B2 (en) * 2007-09-28 2013-01-29 Basf Se Method for obtaining aromatic hydrocarbons from a hydrocarbon mixture

Also Published As

Publication number Publication date
DE1545365C3 (de) 1975-04-03
DE1545365A1 (de) 1970-02-26
DK126860B (da) 1973-08-27
ES318437A1 (es) 1966-09-01
BE670865A (de) 1966-04-13
LU49626A1 (de) 1967-04-13
NL6513214A (de) 1966-04-15
CS167866B2 (de) 1976-05-28
GB1119292A (en) 1968-07-10

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