WO2004067682A1 - Production d'un carburant a faible teneur en soufre - Google Patents

Production d'un carburant a faible teneur en soufre Download PDF

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Publication number
WO2004067682A1
WO2004067682A1 PCT/US2003/001517 US0301517W WO2004067682A1 WO 2004067682 A1 WO2004067682 A1 WO 2004067682A1 US 0301517 W US0301517 W US 0301517W WO 2004067682 A1 WO2004067682 A1 WO 2004067682A1
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Prior art keywords
thiophene
boiling fraction
stream
olefins
gasoline
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PCT/US2003/001517
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English (en)
Inventor
Lubo Zhou
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Uop Llc
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Publication date
Application filed by Uop Llc filed Critical Uop Llc
Priority to AU2003209279A priority Critical patent/AU2003209279A1/en
Priority to PCT/US2003/001517 priority patent/WO2004067682A1/fr
Publication of WO2004067682A1 publication Critical patent/WO2004067682A1/fr

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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
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/02—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing
    • C10G45/04—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing characterised by the catalyst used
    • C10G45/12—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing characterised by the catalyst used containing crystalline alumino-silicates, e.g. molecular sieves
    • 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
    • C10G19/00—Refining hydrocarbon oils in the absence of hydrogen, by alkaline treatment
    • C10G19/02—Refining hydrocarbon oils in the absence of hydrogen, by alkaline treatment with aqueous alkaline solutions
    • 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
    • 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
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/02—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing
    • 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
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/02—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing
    • C10G45/04—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing characterised by the catalyst used
    • C10G45/06—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to eliminate hetero atoms without changing the skeleton of the hydrocarbon involved and without cracking into lower boiling hydrocarbons; Hydrofinishing characterised by the catalyst used containing nickel or cobalt metal, or compounds thereof
    • 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
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
    • 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
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
    • C10G45/60—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used
    • C10G45/64—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used containing crystalline alumino-silicates, e.g. molecular sieves
    • 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
    • C10G67/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only
    • C10G67/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only
    • C10G67/04—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural serial stages only including solvent extraction as the refining step in the absence of hydrogen
    • 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
    • C10G67/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only
    • C10G67/16—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one process for refining in the absence of hydrogen only plural parallel stages only
    • 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
    • C10G7/00—Distillation of hydrocarbon oils
    • C10G7/08—Azeotropic or extractive distillation

Definitions

  • the present invention is directed to a process for reducing the sulfur content in gasoline to a very low level.
  • Gasoline is generally prepared from a number of hydrocarbonaceous blend streams and typical examples include butanes, light straight run naphtha, isomerate, FCC cracked gasoline, hydrocracked naphtha, coker gasoline, alkylate, reformate, ethers and alcohols.
  • FCC fluid catalytic cracking unit
  • the reformer and the alkylation unit account for a major portion of the gasoline pool.
  • FCC gasoline, and if present, coker naphtha and pyrolysis gasoline generally contribute a substantial portion of the gasoline pool sulfur.
  • Sulfur present in the gasoline pool may be in one of several molecular forms, including thiophenes, mercaptans, sulfides and disulfides.
  • thiophenes include thiophene and its alkylated derivatives and benzothiophene
  • Typical mercaptans occurring in the sulfur- containing gasoline streams include thiophenol and the alkyl thiois from ethane thiol to nonanethiol, with potentially smaller amounts of the higher alkyl thiois.
  • US-A-6,228,254 B1 discloses a two-step sulfur removal process comprising a mild hydrotreating step followed by an extraction step to reduce the sulfur content in gasoline to a very low level without significantly reducing the octane of the gasoline.
  • US-A-5,582,714 B1 discloses a process for the removal of sulfur from FCC gasoline by employing a solvent.
  • Preferred solvents are glycols and glycol ethers.
  • the present invention is a process for desulfurizing a gasoline stream while continuing to maintain the octane rating of the blend stock.
  • a gasoline stream containing sulfur compounds and olefins is introduced into a fractionation zone to produce a low boiling fraction containing mercaptan sulfur compounds and olefins, a mid boiling fraction containing thiophene and olefins, and a high boiling fraction containing sulfur compounds.
  • the low boiling fraction containing mercaptan sulfur compounds is, in one embodiment, contacted with an aqueous alkaline solution to selectively remove at least a portion of the mercaptan sulfur compounds.
  • the mid boiling fraction containing thiophene and olefins is contacted with a lean solvent to produce a raffinate stream containing olefins and having a reduced sulfur content relative to the mid boiling fraction and a rich solvent stream enriched in the thiophene.
  • the rich solvent stream enriched in thiophene is separated to produce a hydrocarbonaceous stream rich in thiophene.
  • the thiophene is removed from the mid boiling fraction containing thiophene and olefins by extractive distillation to produce a raffinate stream containing olefins having a reduced sulfur content relative to the mid boiling fraction and a hydrocarbonaceous stream rich in thiophene.
  • the resulting hydrocarbonaceous stream rich in thiophene and the higher boiling fraction containing sulfur compounds is reacted in a hydrodesulfurization reaction zone to produce a hydrocarbonaceous stream having a reduced sulfur concentration.
  • the process of the present invention desulfurizing gasoline containing olefins and introduces a gasoline stream comprising sulfur compounds and olefins into a fractionation zone to produce a low boiling fraction comprising mercaptan sulfur compounds and olefins, a mid boiling fraction comprising thiophene and a high boiling fraction comprising sulfur compounds.
  • the low boiling fraction comprising mercaptan sulfur compounds contacts an aqueous alkaline solution to selectively remove at least a portion of the mercaptan sulfur compounds.
  • Removing at least a portion of the thiophene in the mid boiling fraction produces a raffinate stream having a reduced sulfur content relative to the mid boiling fraction and an extract stream enriched in thiophene. Separating the extract stream enriched in thiophene produces a hydrocarbonaceous stream rich in thiophene. Reacting the high boiling fraction comprising sulfur compounds, optionally together with the hydrocarbonaceous stream rich in thiophene, in a hydrodesulfurization reaction zone to produce a hydrocarbonaceous stream having a reduced sulfur concentration. A desulfurized gasoline comprising olefins is recovered from the process.
  • inventions of the invention vary from the broad embodiment by recovering the extract stream in a specific manner.
  • the invention may recover the extract stream as a rich-solvent stream enriched in the thiophene and the rich-solvent stream enriched in thiophene produces the hydrocarbonaceous stream rich in thiophene.
  • the mid boiling fraction comprising thiophene may enter an extractive distillation zone to produce the raffinate stream having a reduced sulfur content relative to the mid boiling fraction and the hydrocarbonaceous stream rich in thiophene.
  • the drawing is a simplified process flow diagram of a preferred embodiment of the present invention.
  • the production of the mid boiling fraction helps to ensure that essentially no thiophene is recovered with the low boiling fraction while maximizing the recovery of high octane olefin compounds. Since the low boiling fraction containing olefins and mercaptan sulfur compounds is contacted with an aqueous alkaline solution to remove 95% of the mercaptan sulfur compounds, a low boiling stream containing mercaptan sulfur compounds in an amount less than 25 wpm, for example, is produced thereby enabling an overall production of ultra low sulfur gasoline.
  • heavier fractions contain a larger amount of sulfur compounds, and a larger fraction of these sulfur compounds are in the form of aromatic heterocyclic compounds.
  • certain streams commonly blended for gasoline e.g., FCC feedstocks, contain high amounts of the heterocyclic compounds. Gasoline streams containing significant amounts of these heterocyclic compounds are difficult to process. Very severe operating conditions have been conventionally specified for hydrotreating processes to desulfurize gasoline streams, resulting in a large octane penalty.
  • a gasoline stream includes individual refinery streams suitable for use as a blend stock for gasoline, or a blended gasoline stream containing two or more streams, each of which are suitable for use as a gasoline blend stock.
  • a suitable gasoline blend stock when blended with other refinery streams, produces a combined stream which meets the requirements for gasoline, which requirements are well documented in government regulations.
  • Feed to the process preferably comprises a sulfur-containing petroleum fraction which boils in the gasoline boiling range, including FCC gasoline, coker pentane/hexane, coker naphtha, straight run gasoline, and mixtures containing two or more of these streams.
  • gasoline blending streams typically have a normal boiling point within the range of 0°C and 215°C.
  • Feeds of this type include light naphthas typically having a boiling range from C 6 to 165°C; full range naphthas, typically having a boiling range from C 5 to 215°C; heavier naphtha fractions boiling in the range from 127°C to 218°C.
  • a gasoline motor fuel will distill over the range from room temperature to 218°C.
  • Aromatic heterocyclic compounds include alkyl-substituted thiophene, thiophenol, alkylthiophene and benzothiophene.
  • aromatic heterocyclic compounds of particular interest in this application are thiophene, 2- methylthiophene, 3-methylthiophene, 2-ethylthiophene, benzothiophene and dimethylbenzothiophene.
  • Mercaptans which will be removed by the process of this invention often contain from 2-10 carbon atoms, and are illustrated by materials such as 1-ethanethiol, 2-propanethiol, 2-butanethiol, 2-methyl-2- propanethiol, pentanethiol, hexanethiol, heptanethiol, octanethiol, nonanethiol and thiophenol.
  • Sulfur in gasoline originating from these gasoline streams may be in one of several molecular forms, including thiophene, mercaptan, sulfides and disulfides.
  • the sulfur compounds tend to be concentrated in the higher boiling portions of the stream.
  • gasoline streams suited for treating in the present process contain greater than 10 ppm thiophenic compounds.
  • streams containing more than 40 ppm thiophenic compounds, up to 2000 ppm thiophenic compounds and higher may be treated.
  • the sulfur content is desirably less than 150 ppm, preferably less than 100 ppm and most preferably less than 50 ppm.
  • the total sulfur content of the gasoline stream to be desulfurized in the present invention will generally exceed 50 ppm by weight and typically range from 150 ppm to as much as several thousand ppm sulfur. For fractions containing at least 5 volume percent over 193°C, the sulfur content may exceed 1000 ppm by weight and may be as high as 4000 to 5000 ppm by weight or even higher.
  • Many gasoline blend streams also contain olefins. Blend streams originating from the FCC, for example, will be olefinic, with an olefin content of at least 5 or more percent, typically in the range of 10 to 30 percent.
  • a sulfur-containing gasoline stream is introduced into a fractionation zone such as a naphtha three-way splitter, for example, which is preferably operated at a pressure from 135 to 1480 Kpa to produce a low boiling fraction containing mercaptan sulfur compounds and olefins.
  • the low boiling fraction preferably contains no appreciable concentration of thiophene, preferably less than 50 wppm and more preferably less than 10 wppm.
  • the low boiling fraction preferably boils in the range from 38°C to 83°C and preferably has an end boiling point below 71 °C and more preferably below 65°C.
  • the resulting low boiling fraction is contacted with an aqueous alkaline solution to selectively remove at least a portion of the mercaptan sulfur compounds.
  • the extraction of mercaptan sulfur compounds with an aqueous alkaline solution depends on the fact that mercaptans are slightly acidic in nature and in the presence of a strong base tend to form salts-called mercaptides-which have a remarkably high preferential solubility in a basic solution.
  • the extraction step is coupled with a regeneration step and an alkaline stream is continuously recirculated therebetween.
  • the alkaline stream is used to extract mercaptans from the hydrocarbon stream and the resulting mercaptide rich alkaline stream is treated in the regeneration step to remove mercaptide compounds therefrom with continuous cycling of the alkaline stream between the extraction step and the regeneration step.
  • the oxidative regeneration step is typically operated to produce disulfide compounds which are immiscible in the alkaline stream, and the major portion of which disulfide compounds are typically separated therefrom in a settling step. It is preferred that the circulating lean alkaline stream contains a low level of disulfide compounds preferably less than 50 wppm sulfur in order to achieve the desulfurization targets.
  • the alkaline solution utilized in the present invention may comprise any alkaline reagent known to have the capability to extract mercaptans from the low boiling hydrocarbon fraction.
  • a preferred alkaline solution generally comprises an aqueous solution of an alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide and lithium hydroxide.
  • a particularly preferred alkaline solution for use in the present invention is an aqueous solution of 1 to 50% by weight of sodium hydroxide with particularly good results obtained with aqueous
  • the catalyst which is used in the oxidation step, is preferably a metal phthalocyanine catalyst.
  • Particularly preferred metal phthalocyanines comprise cobalt phthalocyanine and iron phthalocyanine.
  • Other metal phthalocyanines include vanadium phthalocyanine, copper phthalocyanine, nickel phthalocyanine, molybdenum phthalocyanine, chromium phthalocyanine, tungsten phthalocyanine, magnesium phthalocyanine, platinum phthalocyanine, hafnium phthalocyanine, palladium phthalocyanine, etc.
  • the metal phthalocyanine in general is not highly polar and, therefore, for improved operation is preferably utilized as a polar derivative thereof.
  • Particularly preferred polar derivatives are the sulfonated derivatives such as the monosulfo derivative, the disulfo derivative, the tri-sulfo derivative, and the tetra-sulfo derivative.
  • the preferred phthalocyanine catalyst can be used in the present invention in one of two modes. First, it can be utilized in a water-soluble form or a form which is capable of forming a stable emulsion in water as disclosed in US-A- 2,853,432 B1.
  • the phthalocyanine catalyst can be utilized as a combination of a phthalocyanine compound with a suitable carrier material as disclosed in US-A-2, 988,500 B1.
  • the catalyst is present as a dissolved or suspended solid in the alkaline stream, which is charged to the regeneration step.
  • the preferred catalyst is cobalt or vanadium phthalocyanine disulfonate, which is typically utilized in an amount of 5 to 1 ,000 wt. ppm of the alkaline stream.
  • the catalyst is preferably utilized as a fixed bed of particles of a composite of the phthalocyanine compound with a suitable carrier material.
  • the carrier material should be insoluble or substantially unaffected by the alkaline stream or hydrocarbon stream under the conditions prevailing in the various steps of the process. Activated charcoals are particularly preferred because of their high adsorptivity under these conditions.
  • the amount of the phthalocyanine compound combined with the carrier material is preferably 0.1 to 2.0 wt. percent of the final composite. Additional details as to alternative carrier materials, methods of preparation, and the preferred amount of catalytic components for the preferred phthalocyanine catalyst for use in this second mode are given in the teachings of US-A-3, 108,081 B1.
  • a mid boiling fraction containing thiophene and olefins is produced and removed from the fractionation zone and preferably boils in the range from 38°C to 149°C and preferably has an end boiling point below 121 °C.
  • the resulting mid boiling fraction is, in one embodiment, contacted with a solvent which is selective to remove thiophene from the mid boiling fraction.
  • the liquid-liquid extraction zone may operate at a capacity and efficiency necessary to remove essentially all of the thiophene.
  • the selective solvents employed in the instant invention in general, are water-miscible organic liquids at the operating temperature of the process.
  • the selective solvents must have a boiling point and a decomposition temperature higher than the operating temperature of the process, wherein the operating temperature of the process refers to the liquid-liquid extraction temperatures at which the feedstock is contacted with the solvent and the solvent regeneration temperature.
  • the term "water-miscible” describes those solvents which are completely miscible with water over a wide range of temperatures, which have a high partial miscibility with water at room temperature, and which are completely miscible with water at operating temperatures.
  • essentially all of the sulfur compounds it is meant that the sulfur content of the treated stream is preferably less than 100 wppm and more preferably less than 50 wppm.
  • Selective solvents employed in the present invention may be low molecular weight, preferably having a molecular weight less than 400 and more preferably less than 200.
  • solvents include polyalkylene glycols and polyalkylene glycol ether.
  • any suitable solvent which demonstrates the desired characteristics herein described may be utilized in the present invention.
  • selective solvents may include, for example, sulfolane, furfural, n-formyl morpholine, n-methyl 2-pyrrolidone, dimethyl sulfoxide, pentaethylene glycol, dimethyl formamide, tetra-ethylene glycol and methoxyl-tri- glycol.
  • the extraction of thiophene can be made to operate at high recovery by circulating more and more solvent.
  • the resulting rich solvent containing the thiophene is distilled to recover a hydrocarbonaceous stream containing the thiophene and to prepare a lean solvent which is returned to the liquid-liquid extraction zone.
  • the mid boiling fraction containing thiophene and olefins may be separated by extractive distillation to produce a raffinate stream containing olefins and having a reduced thiophene content and thereby a reduced sulfur content relative to the mid boiling fraction, and an extract stream enriched in thiophene.
  • the extractive distillation may be conducted while using any of the hereinabove-mentioned solvents which are selective for thiophene.
  • the fractionation zone also produces a high boiling fraction containing sulfur compounds and preferably boils in the range from 65°C to 218°C.
  • the resulting high boiling fraction comprising sulfur compounds and the hydrocarbonaceous stream containing the thiophene derived from the thiophene extraction are introduced into a hydrodesulfurization reaction zone with hydrogen and contacted with one or more beds of the same or different catalysts.
  • a hydrodesulfurization reaction zone with hydrogen and contacted with one or more beds of the same or different catalysts.
  • other reactions may also be performed in one or more sequential catalyst beds including hydrocracking, hydroisomerization, de-alkylation and alkylation, for example.
  • the primary goal of the hydrodesulfurization reaction zone is to remove sulfur from the heterogeneous compounds to thereby produce hydrogen sulfide but in addition, an equally important function is the improvement of the octane rating of the hydrocarbon stream exiting the hydrodesulfurization reaction zone.
  • the octane improvement may be the result of any of the hereinabove-described reactions.
  • One type of preferred catalyst useful in the process of the present invention is a conventional hydrotreating catalyst of the type used to carry out hydrodesulfurization reactions and contain a metal from Group VI and a metal from Group VIII incorporated with an inorganic oxide such as alumina, for example.
  • the commercial catalysts of this type generally fall into one or more of the numerous nickel-molybdenum or cobalt-molybdenum or nickel-tungsten or cobalt-tungsten families.
  • the catalytic metals are preferably supported by alumina or other low acidic inorganic oxide support material. Such catalysts do not have cracking activity because they are non-zeolitic, non-acidic catalysts which function to promote hydrodesulfurization reactions.
  • Such catalysts are well known in the art and the amounts of the hydrogenation components in these catalysts may range from 0.5% to 10% by weight of Group VIII metal components and from 5% to 25% by weight of Group VI metal components, calculated as metals per 100 parts by weight of total catalyst.
  • the hydrogenation components in the catalyst may be in the oxide or sulfide form. If a combination of at least a Group VI and a Group VIII metal component is present as oxides, it will preferably be subjected to presulfiding prior to use.
  • the hydrodesulfurization catalyst comprises one or more components of nickel and/or cobalt and one or more components of molybdenum and/or tungsten.
  • Another type of preferred catalyst useful in the process of the present; invention is a catalyst having hydrodesulfurization capability as well as the ability for hydroisomerization.
  • Commercial catalysts of this type generally contain a zeolitic component. Any catalyst which performs as a combination hydrodesulfurization catalyst and hydroisomerization catalyst is suitable for use in the process of the present invention.
  • a particularly preferred catalyst of this type comprises a matrix, at least one support medium substantially uniformly distributed through the matrix and comprising a silica alumina molecular sieve material having a composition xSi0 2 :Al 2 0 3 :y P 2 0 5 wherein x is at least 0.1 ; a first catalytically active metal phase supported on the support medium, the first catalytically active metal phase comprising a first metal and a second metal each selected from Group VIII of the Periodic Table of the Elements, the first metal being different from the second metal; a second catalytically active metal phase supported on the matrix, the second catalytically active metal phase comprising a third metal and a fourth metal each selected from Group VIII and a fifth metal selected from Group VIB, the third metal being different from the fourth metal.
  • the matrix is preferably selected from the group consisting of alumina, silica alumina, titanium alumina and mixtures thereof. Hydroisomerization conditions will vary depending upon the exact catalyst and feedstock to be used and the final product which is desired.
  • Another type of preferred catalyst which may be used in the present invention is a catalyst which performs selective hydrodesulfurization without complete olefin saturation.
  • Hydrodesulfurization operating conditions preferably include a reaction temperature from 149°C to 343°C, a reaction pressure from 445 to 4240 kPa and a liquid hourly space velocity from 0.5 to 12 hr "1 .
  • the dividing wall column preferably has a conventional design and operate to separates all of the gasoline boiling range hydrocarbons into an overhead stream low boiling fraction containing all of the compounds having boiling points less than the C ⁇ olefins, an intermediate side cut stream for the mid boiling fraction containing Ce and C 7 olefins and a majority of the thiophene, and a bottoms stream for the high boiling fraction containing the heavier C 7 -plus compounds.
  • any fractional distillation there will be some overlap and tailing of compositions between the three cuts.
  • a vertical dividing wall in a vertical mid portion of the column also referred to as the dividing wall portion of the column, distinguishes the dividing wall column.
  • This dividing wall extends between opposing sides of the inner surface of the column and joins it in a substantially fluid tight seal. Thus fluids cannot pass horizontally from one side of the column to the other and must instead travel either over or under the wall.
  • the dividing wall divides the central portion of the column into two parallel fractionation zones or chambers, which may be of different cross-section. Each chamber, and the rest of the column, will contain conventional vapor liquid contacting equipment such as trays or packing.
  • the type of tray and design details such as tray type, tray spacing and layout may vary within the column and between the two parallel chambers of the dividing wail portion of the column.
  • the dividing wall column can give more precise control of the mid boiling fraction composition. Such a column can overcome or at least reduce problems resulting from the tendency of the thiophenes to form azeotropes with the olefinic hydrocarbons.
  • Thiophene exhibits a strongly non-ideal vapor liquid equilibrium in mixtures of other compounds present in FCC naphtha. Azeotropes are known to form between thiophene and many compounds present in gasoline. For example, azeotropes have been reported between thiophene and n-hexane, n- heptane, and benzene.
  • thiophene will also form azeotropes with homologous compounds of these species.
  • Operational data has also indicated that thiophene will accumulate in lighter boiling fractions than would be expected based upon its normal boiling point of 84°C.
  • the dividing wall column can permit a tighter boiling range specification of the mid boiling fraction and allow a reduction in the its flow rate along with improved operational control. This tighter control on the composition of the mid boiling fraction also offers advantages in its downstream treating such as reducing its toluene concentration. Reduced toluene in the mid boiling fraction benefits treatment by solvent extraction to remove the sulfur compounds.
  • the drawing illustrates the process in a simplified schematic flow diagram that excludes details of pumps, instrumentation, heat-exchange and heat-recovery circuits, compressors and similar hardware that actual practice of the invention will employ.
  • a naphtha stream from a fluid catalytic cracker containing sulfur and olefins enters fractionation zone 2 via line 1.
  • a low boiling fraction containing mercaptan sulfur compounds and olefins is removed via line 3 and introduced into mercaptan extraction zone 6.
  • a resulting low boiling fraction containing olefins and a reduced concentration of mercaptan sulfur compounds is removed from mercaptan extraction zone 6 via lines 9 and 13.
  • a mid boiling fraction containing thiophene compounds and olefins is removed from fractionation zone 2 via line 4 and introduced into thiophene extraction zone 7.
  • a raffinate stream containing a mid boiling fraction including olefins and having a reduced concentration of thiophene compounds is removed
  • a mid boiling hydrocarbonaceous stream containing an enhanced concentration of thiophene is removed from thiophene extraction zone 7 via lines 11 and 14 and introduced into hydrodesulfurization reaction zone 8.
  • a high boiling fraction containing sulfur compounds is removed from fractionation zone 2 via lines 5 and 14 and is introduced into hydrodesulfurization reaction zone 8.
  • a high boiling fraction having a reduced concentration of sulfur compounds is removed from hydrodesulfurization reaction zone 8 via lines 12 and 13 and recovered.
  • a full boiling range naphtha produced in a fluid catalytic cracker (FCC) in an amount of 6837 m 3 /day having an octane rating of 86.6 and containing 28 weight percent olefins and 5000 weight parts per million (wppm) sulfur is introduced into a naphtha splitter to produce a low boiling fraction in an amount of 1334 m 3 /day having an octane rating of 91.1 and containing 57 weight percent olefins and 1537 wppm sulfur, a mid boiling fraction or heart cut in an amount of 2039 m 3 /day having an octane rating of 83.8 and containing 48 weight percent olefins and 2091 wppm sulfur and a high boiling fraction in an amount of 3464 m 3 /day having an octane rating of 86.3 and containing 10 weight percent olefins and 7400 wppm sulfur.
  • FCC fluid catalytic cracker
  • the low boiling fraction produced in the naphtha splitter having a thiophene concentration of less than 40 wppm is extracted with an aqueous sodium hydroxide stream to remove mercaptan sulfur compounds and to produce a resulting hydrocarbon stream in an amount of 1334 m 3 /day having an octane rating of 91.2 and containing 57 weight percent olefins and only 43 wppm sulfur.
  • the mid boiling fraction or heart cut is extracted with sulfolane to produce a raffinate stream in an amount of 1880 m 3 /day having an octane rating of 83.2 and containing 48 weight percent olefins and only 77 wppm sulfur, and the sulfolane extract stream rich in thiophene is distilled to produce a resulting hydrocarbon stream in an amount of 160 m 3 /day having an octane rating of 91.2 and containing 47 weight percent olefins and 23,051 wppm sulfur.
  • the high boiling fraction produced in the naphtha splitter and 160 m 3 /day hydrocarbon stream containing 23,051 wppm sulfur are introduced into a hydrodesulfurization reaction zone to remove sulfur from the sulfur bearing hydrocarbonaceous compounds and produce hydrogen sulfide, and to subsequently produce a resulting hydrocarbonaceous stream in an amount of 3560 m 3 /day having an octane rating of 83.9 and containing 0.6 weight percent olefins and only 10 wppm sulfur.

Abstract

L'invention porte sur un procédé de désulfuration de carburants permettant de maintenir l'indice d'octane de l'apport initial. A cet effet on introduit le carburant contenant des composés sulfurés et des oléfines dans une zone de fractionnement de manière à obtenir: une fraction à bas point d'ébullition contenant des composés sulfurés de mercaptan et des oléfines; une fraction à point d'ébullition moyen contenant du thiophène et des oléfines; et une fraction à point d'ébullition élevé contenant des composés sulfurés. On met en contact la fraction à bas point d'ébullition avec une solution alcaline qui en retire sélectivement les composés sulfurés de mercaptan; on extrait de la fraction à point d'ébullition moyen un produit raffiné riche en oléfines à teneur en soufre moindre que celle de la fraction à point d'ébullition moyen ainsi qu'un hydrocarbure riche en thiophène; puis on soumet l'hydrocarbure riche en thiophène et la fraction à point d'ébullition élevé à une réaction d'hydrodésulfuration pour obtenir l'hydrocarbure à teneur en soufre réduite.
PCT/US2003/001517 2003-01-17 2003-01-17 Production d'un carburant a faible teneur en soufre WO2004067682A1 (fr)

Priority Applications (2)

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AU2003209279A AU2003209279A1 (en) 2003-01-17 2003-01-17 Production of low sulfur gasoline
PCT/US2003/001517 WO2004067682A1 (fr) 2003-01-17 2003-01-17 Production d'un carburant a faible teneur en soufre

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PCT/US2003/001517 WO2004067682A1 (fr) 2003-01-17 2003-01-17 Production d'un carburant a faible teneur en soufre

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012005948A3 (fr) * 2010-06-29 2012-05-10 Saudi Arabian Oil Company Élimination de composés soufrés de flux de pétrole
WO2015073178A1 (fr) * 2013-11-14 2015-05-21 Uop Llc Appareils et procédés pour la désulfuration de naphta
CN104801347A (zh) * 2015-03-31 2015-07-29 西安工业大学 羧基取代金属酞菁敏化Zn2SnO4粉末的催化脱硫剂及其制备方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4131537A (en) * 1977-10-04 1978-12-26 Exxon Research & Engineering Co. Naphtha hydrofining process
US5582714A (en) * 1995-03-20 1996-12-10 Uop Process for the removal of sulfur from petroleum fractions

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4131537A (en) * 1977-10-04 1978-12-26 Exxon Research & Engineering Co. Naphtha hydrofining process
US5582714A (en) * 1995-03-20 1996-12-10 Uop Process for the removal of sulfur from petroleum fractions

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012005948A3 (fr) * 2010-06-29 2012-05-10 Saudi Arabian Oil Company Élimination de composés soufrés de flux de pétrole
US9005432B2 (en) 2010-06-29 2015-04-14 Saudi Arabian Oil Company Removal of sulfur compounds from petroleum stream
WO2015073178A1 (fr) * 2013-11-14 2015-05-21 Uop Llc Appareils et procédés pour la désulfuration de naphta
CN104801347A (zh) * 2015-03-31 2015-07-29 西安工业大学 羧基取代金属酞菁敏化Zn2SnO4粉末的催化脱硫剂及其制备方法

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