EP1972678B1 - Method of desulphurating hydrocarbon fractions from steam cracking effluent - Google Patents

Method of desulphurating hydrocarbon fractions from steam cracking effluent Download PDF

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Publication number
EP1972678B1
EP1972678B1 EP08290204A EP08290204A EP1972678B1 EP 1972678 B1 EP1972678 B1 EP 1972678B1 EP 08290204 A EP08290204 A EP 08290204A EP 08290204 A EP08290204 A EP 08290204A EP 1972678 B1 EP1972678 B1 EP 1972678B1
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Prior art keywords
catalyst
stage
cut
alkylation
fraction
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German (de)
French (fr)
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EP1972678A1 (en
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Florent Picard
Quentin Debuisschert
Annick Pucci
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IFP Energies Nouvelles IFPEN
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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
    • 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
    • C10G67/08—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 acid treatment 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
    • C10G69/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process
    • C10G69/02—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process plural serial stages only
    • C10G69/12—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process plural serial stages only including at least one polymerisation or alkylation step
    • C10G69/123—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process plural serial stages only including at least one polymerisation or alkylation step alkylation
    • 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
    • C10G29/00—Refining of hydrocarbon oils, in the absence of hydrogen, with other chemicals
    • C10G29/20—Organic compounds not containing metal atoms
    • C10G29/205—Organic compounds not containing metal atoms by reaction with hydrocarbons added to the hydrocarbon oil
    • 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
    • C10G45/32—Selective hydrogenation of the diolefin or acetylene 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
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/32—Selective hydrogenation of the diolefin or acetylene compounds
    • C10G45/34—Selective hydrogenation of the diolefin or acetylene compounds characterised by the catalyst used
    • C10G45/40—Selective hydrogenation of the diolefin or acetylene compounds characterised by the catalyst used containing platinum group metals 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
    • C10G69/00—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process
    • C10G69/14—Treatment of hydrocarbon oils by at least one hydrotreatment process and at least one other conversion process 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
    • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
    • C10G2400/02—Gasoline

Definitions

  • the present invention relates to a process for treating hydrocarbon steam cracking effluents.
  • the steam cracking process is a well-known petrochemical process, which is the basis for producing the major petrochemical intermediates, in particular ethylene and propylene.
  • Steam cracking produces, in addition to ethylene and propylene, significant quantities of less valuable co-products, especially aromatic pyrolysis gasoline, which is found in significant quantities when cracking propane or butane, and even more so. , when you crack naphtha, diesel or even condensates.
  • the aim of the invention is to find a technically simple and inexpensive solution to the aforementioned problem, in order to produce at the petrochemical site C7 + or C8 + or C9 + fractions from steam cracking units that can be used directly as a low sulfur gasoline base. .
  • the patent US 6,048,451 describes how to desulphurize species from catalytic cracking by a process of converting the sulfur compounds to heavier sulfur compounds using an alkylating agent in the presence of an acid catalyst.
  • the alkylating agent includes olefins or alcohols.
  • this invention is described for application to catalytic cracking gasolines and is intended to increase the sulfur compounds of the thiophene and methylthiophene type.
  • the invention therefore makes it possible, by departing from the conventional technical philosophy of reducing the sulfur of the pyrolysis gasolines by treatment under hydrogen, to produce low sulfur pyrolysis gasolines which can be used directly as a gasoline base and which have a high index. octane.
  • steps a), b), c), and e) as described in this application are often present in petrochemical complexes equipped with steam cracking units.
  • the investment required to produce pyrolysis gasolines depleted in sulfur is then weak since it consists only in the implementation of step d) of increasing the sulfur compounds.
  • the charge is derived from one or more fractionations of steam cracking gasoline and corresponds to a section whose boiling point is generally between 0 ° C. and 250 ° C., preferably between 10 ° C. and 220 ° C.
  • this feed consists essentially of CS-C11 with traces (a few wt%) of C3, C4, C12, C13, C14.
  • This charge generally undergoes the selective hydrogenation step a) and the effluent from step a) is sent to step b).
  • Step a) consists in bringing the charge to be treated into contact with hydrogen introduced in excess into one or more reactors containing a hydrogenation catalyst. The hydrogen flow rate is adjusted in order to dispose of it in sufficient quantity to theoretically hydrogenate all the diolefins, acetylenics and alkenyl aromatics and to maintain an excess of hydrogen at the reactor outlet.
  • the selective hydrogenation step HD1 also known as the hydrodenialization step, is well known to those skilled in the art and is described in particular in the book Petrochemical Processes, Volume 1, Technip Edition, A. Chauvel and G. Lefebvre, pages 155-160 .
  • the operating temperature during step a) is generally between 50 ° C. and 200 ° C.
  • the space hourly speed is between 1 h -1 and 6 h -1
  • the pressure is between 1.0 MPa. and 4.0 MPa.
  • step a It is a fractionation step in one or more distillation columns of the feedstock or the effluent of step a) in order to produce at least one light cut consisting essentially of C5, an intermediate cut consisting essentially of C6 or C6-C7 or C6-C8 typically for the production of aromatics and a heavy cut consisting essentially of C7 + or C8 + or C9 + typically for the production of gasoline.
  • the feedstock undergoes two successive distillations in order to produce the 3 cuts.
  • the first distillation results in a light cut consisting essentially of C5 and a C6 + cut.
  • the C6 + cut is sent to a second distillation column which leads to an intermediate cut consisting essentially of C6 or C6-C7 or C6-C8 for the production of aromatics and a heavy cut consisting essentially of C7 + or C8 + or C9 + intended for the production of gasoline.
  • the feedstock firstly passes through a first distillation in order to obtain a light cut consisting essentially of C5 and a C6 + cut which is sent to step a).
  • the effluent of step a) then undergoes distillation so as to obtain an intermediate cut consisting essentially of C6 or C6-C7 or C6-C8 intended for the production of aromatics and a heavy cut consisting essentially of C7 + or C8 + or C9 + for the production of gasoline.
  • the intermediate cut is then sent to step c) hydrodesulphurization and deep hydrogenation while the heavy cut is sent to step d) alkylation.
  • the effluent of the alkylation step d) is then sent to the distillation step e).
  • Step c) comprises contacting the intermediate cut to be treated with hydrogen in one or more reactors containing hydrogenation and hydrodesulfurization catalyst.
  • This step is also well known to those skilled in the art and is particularly described in the book Petrochemical Processes, Volume 1, Technip Edition, A. Chauvel and G. Lefebvre, page 160 .
  • the operating temperature during stage c) is generally between 220 ° C. and 380 ° C.
  • the space hourly speed is between 1 h -1 and 6 h -1
  • the pressure is between 1.0 MPa. and 4.0 MPa.
  • the alkylation step d) is a step of treatment of the C7 +, C8 + or C9 + heavy cut, and is mixed with a fraction of the C5 light cut consisting of an acid catalyst treatment which makes it possible to desulphurize the fraction of the said boiling cut. in gasoline without the addition of hydrogen by increasing the sulfur compounds.
  • the feedstock treated in the alkylation step d) is a hydrocarbon fraction derived from a steam cracking unit. The charge corresponds to a C7 +, C8 + or C9 + cut pretreated in a hydrogenation unit HD1.
  • the unit HD1 used in step a) is intended to selectively hydrogenate diolefins, acetylenes and a fraction of the alkenylaromatician.
  • the filler is generally a mixture of olefinic, aromatic, paraffinic and naphthenic compounds as well as sulfur up to 20 ppm by weight at 1000 pm weight.
  • the alkylation step d) is carried out in the alkylation section which may comprise one or more reactors.
  • the main objective of step d) is to increase the sulfur compounds, by adding mono-olefins present in the feedstock.
  • Sulfur compounds that can react are thiophene compounds of alkylthiophene type, and to a lesser extent mercaptan type compounds. These reactions do not involve any transformation of the aromatic compounds because these compounds have a much lower reactivity than the olefinic and sulfur compounds and are therefore not transformed, which is favorable to maintaining the octane number.
  • alkylate alkylthiophenes whose alkyl groups contain 1 to 4 carbon atoms in particular alkylthiophenes of the ethylthiophene, dimethylthiophene, propylthiophene and butylthiophene type, with monoolefins comprising 7 or more carbon atoms and aromatic alkenyls.
  • alkylthiophenes whose alkyl groups contain 1 to 4 carbon atoms
  • monoolefins comprising 7 or more carbon atoms and aromatic alkenyls.
  • the reactivity of the long olefins is lower than the reactivity of the short olefins, it may be advantageous to mix a feed containing butenes or pentenes with the feedstock.
  • the alkylation step d) generally consists in bringing the fraction to be treated into contact with a solid acid catalyst under conditions of flow, temperature and pressure chosen to promote the addition of the monoolefins and alkenylaromatic compounds to the sulfur compounds.
  • the heavy sulfur compounds thus formed generally have a boiling point higher than the typical end point of the gasoline, that is to say higher than 220 ° C. Typically, they can be separated from gasoline by simple distillation.
  • the catalyst employed in the alkylation step d) is preferably a solid acid catalyst. Any catalyst capable of promoting the addition of unsaturated hydrocarbon compounds to the sulfur compounds can be used in the present invention.
  • Zeolites, clays, functionalized silicas, silico-aluminates having acidity or grafted supports of acidic functional groups or acidic ion exchange resins are generally used.
  • acidic ion exchange resins are used, most preferably polymeric acidic ion exchange resins such as sulfonic acid resins.
  • the resins marketed by the company Rhom & Haas sounds the name of Amberlyst15, Amberlyst35 or Amberlyst 36 can be used. It is also possible to use the TA801 resin marketed by the company Axens.
  • catalysts based on phosphoric acid as described in the patent US 6,736,963 obtained by the comalaxing of phosphoric acid and amorphous silica of kieselguhr type.
  • acids based on inorganic oxides including aluminas, silica, silica aluminas and more particularly zeolites such as zeolites faujasites, mordenites, L, omega, X, Y, beta, ZSM-3, ZSM-4, ZSM-5, ZSM-18 and ZSM-20.
  • the catalysts can also consist of a mixture of different acids of Lewis (e.g. BF4, BC13, SbF5 and AlCl3) with a non-zeolitic metal oxide such as silica, alumina, silica-aluminas.
  • the operating temperature is generally adjusted according to the chosen catalyst, in order to reach the conversion rate of the desired sulfur compounds.
  • the temperature is generally between 30 ° C and 300 ° C, and preferably between 40 ° C and 250 ° C.
  • the temperature does not exceed 200 ° C and preferably 150 ° C to preserve the integrity of the catalyst.
  • the temperature is greater than 100 ° C and less than 250 ° C, preferably greater than 140 ° C and less than 220 ° C.
  • the volume of catalyst used is such that the ratio between the volume flow rate of the feedstock to be treated and the catalytic volume, also called the space hourly speed, is typically between 0.05 h -1 and 5 h -1 , preferably between 0, 07 h -1 and 3 h -1 and very preferably between 0.1 h -1 and 2 h -1 .
  • the pressure is generally adjusted to maintain the reaction mixture in the liquid phase.
  • the pressure is between 1.0 MPa and 4.0 MPa, preferably between 1.5 MPa and 4.0 MPa.
  • the alkylation step d) is typically carried out in at least one fixed bed cylindrical reactor. However, it is preferable to have several reactors operated in series or in parallel in order to guarantee continuous operation despite deactivation of the catalyst. According to a preferred embodiment of the invention, the alkylation step is carried out in two identical reactors connected to each other, one being in operation while the other is stopped and loaded with fresh ready catalyst. to be used. This device makes it possible in particular to operate the unit continuously during the replacement phases or during the regeneration phases in situ of the spent catalyst.
  • the alkylation step is carried out in 3 reactors which can be operated in parallel or in series.
  • the feed successively feeds two reactors, one containing a partially spent catalyst, and the second containing fresh catalyst.
  • the third reactor is left stationary, charged with fresh catalyst and ready for use.
  • the catalyst of the first reactor is deactivated, the reactor is stopped, the second reactor is then operated in first position and the third reactor initially stopped is operated in second position.
  • the first stopped reactor can then be discharged and its catalyst replaced with a batch of fresh catalyst.
  • olefin dimerization reactions can occur in the reactor, resulting in an increase in the treated hydrocarbon fraction.
  • the aromatic compounds are very little or not even converted in the reactor.
  • the conversion of aromatics is less than 10%, preferably 5%, which allows to preserve the octane number of the cut.
  • the alkylation reactions of sulfur compounds and of olefin dimerization are exothermic, that is, they are favored at low temperature and give off heat.
  • the recycling rate defined as the recycled effluent flow divided by the fresh feed rate is typically between 0.2 and 4 and preferably between 0.5 and 2.
  • the catalyst used is an ion exchange resin
  • the charge is generally injected through the bottom of the reactor, at a linear velocity sufficient to cause suspension of the catalyst beads.
  • This type of implementation has the advantage of limiting the temperature gradient in the reactor, that is to say the temperature difference between the outlet and the inlet of the reactor, and of ensuring a good distribution of the liquid hydrocarbon feedstock and good thermal homogeneity in the reactor.
  • a system for supplementing / withdrawing the catalyst can be added to the reactor in order to continuously withdraw spent catalyst and make a supplement of fresh catalyst.
  • an acid ion exchange resin catalyst is used because it is a catalyst which proves to be very active and which makes it possible to operate the reactor at a low temperature. That is to say at a temperature generally below 200 ° C, which is to limit the formation of gums and polymers which are easily formed products by condensation reaction of unsaturated compounds of polyolefin or alkenylaromatic type in the intermediate fractions of steam cracking.
  • the space velocity (VVH) is adjusted to allow operation at the lowest temperature possible, compatible with the desired performance.
  • the reactor can be operated at a VVH between 0.1 hr-1 and 2 hr-1 and a temperature below 80 ° C.
  • the catalyst deactivates, it is necessary to gradually increase the temperature to maintain the performance. The temperature can then be increased gradually until it reaches generally 150 ° C. or even 200 ° C. maximum.
  • a fraction of the C5 light cut is injected into the C7 +, C8 + or C9 + heavy cut and then sent to the alkylation step. This mixture makes it possible to increase the amount of reactive monoolefins and thus to promote the conversion of the sulfur compounds.
  • step d) It is a step of distillation of the effluent of step d) intended to produce a light fraction that can be used directly as a gasoline base, and a C11 + or C12 + heavy fraction rich in sulfur compounds and used as an average or fuel distillate.
  • the light fraction has an end point generally less than 230 ° C and preferably less than 220 ° C.
  • the figure 1 presents a preferred embodiment of the invention.
  • the feedstock is fed via line 1 and treated in a selective hydrogenation unit HD1 to carry out in particular a prior art alkenyl reduction and dedenization.
  • the dedenized charge flows through line 2 and is fractionated in a distillation column 3 into a fraction C5 flowing through line 4, typically recycled to steam cracking or used as a gasoline base, and a C6 + fraction flowing in line 5.
  • the C6-C n fraction feeds a hydrotreating unit HD2 which performs a thorough desulfurization of the C6-Cn cut and a deep hydrogenation of mono-olefins.
  • a hydrotreating unit HD2 which performs a thorough desulfurization of the C6-Cn cut and a deep hydrogenation of mono-olefins.
  • the LD145 / HR406 catalysts marketed by Axens can be used to carry out this step.
  • the treated C6-Cn cut evacuated via line 10 may have, for example, less than 1 ppm by weight of sulfur and less than 50 ppm by weight of mono-olefins. It is generally sought to minimize the hydrogenation of the aromatics in this section in order to maximize their subsequent recovery for petrochemical applications.
  • the cut C n + 1 + leaving the bottom of the column 7 by the line 9 feeds the section ALK said alkylation section to produce an alkylated cut recovered by the line 11.
  • a fraction of the C5 cut from column 3 is injected via line 6 into the charge of the alkylation section to increase the amount of reactive olefins and thereby promote the conversion of sulfur compounds.
  • the cut produced in the alkylation section ALK is sent via line 11 to a distillation column 12 to produce, at the top, a C n + 1 -C 12 cut recovered by the sulfur-depleted line 13 for use as a base gasoline, and in bottom a C12 + cut recovered by line 14 which can be used as domestic fuel and in which the alkylated sulfur compounds are concentrated in the alkylation section.
  • the C n + 1 -C 12 cut recovered by line 13 generally contains less than 100 ppm of sulfur or even less than 50 pm of sulfur or for the purpose of the production of very low sulfur species, less than 10 ppm of sulfur.
  • the figure 2 details a preferred embodiment of the alkylation step d).
  • the alkylation section consists of two reactors R1 and R2 which can be operated in parallel.
  • the mixture thus formed (line 9a) is sent to the reactor R1 via line 9b and the alkylation product is recovered via line 9d.
  • the reactor R2 is charged with fresh and active catalyst and left stationary.
  • the reactor R1 is stopped and the feedstock to be treated is sent to the reactor R2 via the line 9c.
  • the alkylation product is recovered via line 9e.
  • the catalyst contained in the reactor R1 is discharged and replaced with a fresh catalyst charge. This particular device makes it possible to maintain a continuous operation even when the catalyst is deactivated.
  • Naphtech steam-cracking effluents are fractionated in a treatment plant for these effluents, comprising a primary distillation, to produce, in particular, an ⁇ -pyrrolysis gasoline cut, essentially comprising C5 and heavier hydrocarbons up to an ASTM endpoint of 210 ° C.
  • This essence cut of pyrolysis ⁇ has the following characteristics: - Sulfur content: 200 ppm by weight - Composition of the pyrolysis gasoline fraction ⁇ (% by weight) C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 + Total n-paraffins 0.0 0.1 3.6 1.3 0.2 0.0 0.0 0.0 0.0 0.0 5.2 i-paraffins 0.0 2.7 1.4 0.3 0.4 0.1 0.0 0.0 0.0 4.9 monoolefins 0.2 0.6 5.3 1.7 0.7 1.0 0.4 0.3 1.0 0.9 12.1 diolefins 0.0 1.1 10.3 3.9 3.4 1.8 0.1 20.8 naphthenes 0.5 1.3 0.5 0.1 0.0 0.0 0.0 2.5 aromatics 26.6 11.8 4.2 2.0 1.9 0.7 0.1 47.3 aromatic alkenyls 3.5 3.1 0.5 0.0 0.0 7.1 Total 0.2 1.8 22.4 36.4 13.5 9.2 5.6 6.2 3.6 1.1 100.0
  • This essence pyrolysis cut is treated according to the process scheme described in figure 1 .
  • the product thus hydrotreated is distilled to separate the fractions C5, C6-C8 and C9 +.
  • Gasoline ⁇ is then distilled in order to recover a first light fraction ⁇ 1 whose boiling range corresponds to the gasoline fraction, and a heavy fraction ⁇ 2.
  • the end point of gasoline ⁇ 1 can be adjusted according to the essence specifications of each country.
  • Gasoline ⁇ 1 can be incorporated directly into the low-sulfur gasoline pool.
  • Gasoline ⁇ 2 can be used as domestic fuel.

Description

La présente invention concerne un procédé de traitement d'effluents de vapocraquage d'hydrocarbures. Le procédé de vapocraquage est un procédé pétrochimique bien connu, à la base de production des grands intermédiaires de la pétrochimie, en particulier de l'éthylène et du propylène. Le vapocraquage produit, outre de l'éthylène et du propylène, des quantités importantes de coproduits moins valorisables, notamment de l'essence de pyrolyse aromatique, qui se trouve en quantité notable lorsque l'on craque du propane ou du butane, et plus encore, lorsque l'on craque du naphta, du gazole voire des condensats.The present invention relates to a process for treating hydrocarbon steam cracking effluents. The steam cracking process is a well-known petrochemical process, which is the basis for producing the major petrochemical intermediates, in particular ethylene and propylene. Steam cracking produces, in addition to ethylene and propylene, significant quantities of less valuable co-products, especially aromatic pyrolysis gasoline, which is found in significant quantities when cracking propane or butane, and even more so. , when you crack naphtha, diesel or even condensates.

L'essence de pyrolyse brute est souvent hydrogénée en deux étapes, avec un fractionnement intermédiaire pour produire typiquement une coupe C5, différentes coupes destinées à produire des bases aromatiques et des bases essence ou fioul. Les schémas existants permettent généralement de produire une coupe C6 pour extraire le benzène et une coupe C7+ ou bien une coupe C6-C7-C8 pour extraire le benzène, le toluène et les xylènes et une coupe C9+.
Par définition, une coupe Cn est une coupe composée essentiellement d'hydrocarbures à n atomes de carbone. Une coupe Cn+ est une coupe composée essentiellement d'hydrocarbures à au moins n atomes de carbone et allant jusqu'aux hydrocarbures ayant 12 atomes de carbones. Cette coupe peut généralement comprendre des C13 voir des C14. Par exemple, une coupe C8+ comprend essentiellement des hydrocarbures en C8, C9, C10, C11, C12 et cette coupe peut généralement comprendre des C13 voir des C14.
La coupe C5 est généralement recyclée au vapocraqueur ou envoyée au pool essence. La coupe C6-C7-C8, notée par la suite C6-C8, composée essentiellement d'hydrocarbures à 6, 7 ou 8 atomes de carbone, est utilisée comme base de production d'aromatiques (benzène, toluène et xylènes). La coupe C9+ est généralement soit utilisée comme fuel domestique, soit comme base d'essence automobile. Dans ce dernier cas, il est généralement nécessaire de séparer la fraction lourde correspondante à une température d'ébullition ASTM supérieure à 220°C, de la coupe C9-220°C utilisée comme une base essence compatible avec les points de coupe de l'essence.
Par ailleurs, les essences de pyrolyse ont des teneurs en soufre élevées, notamment celle de la coupe C9+ est souvent au delà des spécifications en cours (50 à 150 ppm poids) ou à venir. En effet, ces essences contiennent de l'ordre de 300 ppm poids de soufre ainsi que des teneurs en composés insaturés réactifs élevés qui les rendent inutilisable sans traitement complémentaire.
Les fractions C6 ou C6-C7 ou C6-C8 destinées à la production de bases aromatiques sont traitées dans une étape de dédiénisation (hydrogénation sélective) afin d'éliminer les composés insaturés réactifs tels que les dioléfines, les composés acétyléniques et les alkénylaromatiques puis dans une étape d'hydrodésulfuration pour éliminer les mono-oléfines ainsi que les composés soufrés, sans toutefois hydrogéner les composés aromatiques. Les alkénylaromatiques sont des composés hydrocarbonés constitués d'au moins un noyau aromatique comportant au moins un groupement alkényle.
Les fractions C7+ ou C8+ ou C9+ destinées à la production d'essence sont souvent traitées dans une étape de dédiénisation puis utilisées directement comme base essence après une étape éventuelle de fractionnement pour éliminer les composés C11+ ou C12+ et obtenir la spécification de point final de l'essence. Toutefois, leur teneur en soufre devient incompatible avec l'évolution des normes sur la teneur en soufre maximale de l'essence qui tend à descendre en dessous de 50 ppm, ou 30 ppm voire 10 ppm poids.
Trois voies sont actuellement mises en oeuvre ou envisagées pour faire face à cette situation, en particulier pour les vapocraqueurs existants.

  1. 1) la voie 1 consiste à modifier les unités d'hydrotraitement existantes pour accroître fortement la capacité et la désulfuration. Des catalyseurs de désulfuration adéquats existent, les plus utilisés étant principalement des catalyseurs à base de nickel et molybdène, ou nickel et tungstène ou cobalt et molybdène, sur support alumine.
  2. 2) la voie 2 consiste à rajouter une nouvelle unité de désulfuration finale par traitement à l'hydrogène de la fraction valorisable en coupe essence.
    Ces deux premières voies conduisent à des investissements supplémentaires notables et une consommation d'hydrogène, gaz de plus en plus rare sur les sites de raffinage et de pétrochimie, sans gain sur la valorisation des produits qui restent des bases essence de qualité assez médiocre. De plus, la désulfuration poussée s'accompagne d'une réduction limitée de la teneur en aromatiques que l'on cherche à minimiser, mais qui reste défavorable pour l'indice d'octane de l'essence, et donc pour sa valorisation.
  3. 3) La voie 3 consiste à céder la fraction essence telle que produite à une raffinerie de pétrole qui réalisera une désulfuration finale. Cette option conduit à une moins value importante sur le prix de l'essence ainsi cédée.
The crude pyrolysis gasoline is often hydrogenated in two stages, with intermediate fractionation to typically produce a C5 cut, different cuts to produce aromatic bases and gasoline or fuel bases. Existing schemes generally produce a C6 cut to extract benzene and a C7 + cut or a C6-C7-C8 cut to extract benzene, toluene and xylenes and a C9 + cut.
By definition, a Cn cut is a section consisting essentially of hydrocarbons with n carbon atoms. A Cn + cut is a cross-section composed essentially of hydrocarbons with at least n carbon atoms and up to hydrocarbons having 12 carbon atoms. This cut can generally include C13 or C14. For example, a C8 + cut essentially comprises hydrocarbons C8, C9, C10, C11, C12 and this cut can generally include C13 or C14.
The C5 cut is usually recycled to the steam cracker or sent to the gasoline pool. The C6-C7-C8 cut, hereinafter C6-C8, composed essentially of hydrocarbons with 6, 7 or 8 carbon atoms, is used as a base for the production of aromatics (benzene, toluene and xylenes). The C9 + cut is generally used as a domestic fuel or as a motor gasoline base. In the latter case, it is generally necessary to separate the corresponding heavy fraction at an ASTM boiling point higher than 220 ° C, from the C9-220 ° C cut used as a gasoline base compatible with the cutting points of the petrol.
In addition, pyrolysis gasolines have high sulfur contents, especially that of the C9 + cut is often beyond current specifications (50 to 150 ppm weight) or to come. In fact, these gasolines contain about 300 ppm by weight of sulfur as well as high levels of unsaturated reactive compounds which make them unusable without additional treatment.
The C6 or C6-C7 or C6-C8 fractions intended for the production of aromatic bases are treated in a step of dedienization (selective hydrogenation) in order to eliminate the reactive unsaturated compounds such as diolefins, acetylenic compounds and alkenylaromatic compounds. a hydrodesulfurization step to remove the mono-olefins as well as the sulfur compounds, without however hydrogenating the aromatic compounds. Alkenyl aromatics are hydrocarbon compounds consisting of at least one aromatic ring having at least one alkenyl group.
The C7 + or C8 + or C9 + fractions for the production of gasoline are often treated in a dedenization step and then used directly as a gasoline base after a possible fractionation step to remove the C11 + or C12 + compounds and obtain the endpoint specification of the petrol. However, their sulfur content becomes incompatible with the evolution of standards on the maximum sulfur content of gasoline which tends to fall below 50 ppm, or 30 ppm or even 10 ppm weight.
Three pathways are currently being implemented or envisaged to deal with this situation, in particular for existing steam crackers.
  1. 1) Track 1 involves modifying existing hydrotreating units to significantly increase capacity and desulphurization. Catalysts Suitable desulfurization exists, the most used being mainly catalysts based on nickel and molybdenum, or nickel and tungsten or cobalt and molybdenum, supported alumina.
  2. 2) Route 2 consists of adding a new final desulphurization unit by hydrogen treatment of the recoverable fraction in gasoline fraction.
    These first two routes lead to significant additional investments and hydrogen consumption, a gas that is increasingly rare on refinery and petrochemical sites, with no gain on the valorization of products that remain gasoline bases of rather poor quality. In addition, the extensive desulphurization is accompanied by a limited reduction in the aromatics content that is sought to minimize, but which remains unfavorable for the octane number of gasoline, and therefore for its valuation.
  3. 3) Track 3 is to transfer the gasoline fraction as produced to an oil refinery that will achieve final desulphurization. This option leads to a significant reduction in the price of gasoline thus sold.

Le but de l'invention est de trouver une solution techniquement simple et peu coûteuse au problème précité, afin de produire sur le site pétrochimique des fractions C7+ ou C8+ ou C9+ issues d'unités de vapocraquage directement utilisables comme base essence à faible teneur en soufre.The aim of the invention is to find a technically simple and inexpensive solution to the aforementioned problem, in order to produce at the petrochemical site C7 + or C8 + or C9 + fractions from steam cracking units that can be used directly as a low sulfur gasoline base. .

Les différents schémas d'hydrotraitement des fractions hydrocarbonées liquides issues d'unités de vapocraquage sont décrits dans la littérature. Citons par exemple la demande de brevet FR2858981 qui décrit un schéma de production de différentes coupes issues d'une unité de vapocraquage par la mise en oeuvre de 3 étapes distinctes d'hydrotraitement.
Toutefois, les solutions existantes ou envisagées consistent exclusivement en la mise en oeuvre d'étapes d'hydrodésulfuration qui nécessitent la présence d'hydrogène dans un procédé coûteux et ne décrivent pas la possibilité de traiter l'une des fractions issue de l'unité de vapocraquage par un procédé basé sur l'alourdissement des composés soufrés sur un catalyseur acide.
Par ailleurs, la désulfuration de fractions hydrocarbonées par traitement sur catalyseur acide est elle aussi largement décrite dans la littérature. Par exemple, le brevet US 6,048,451 décrit comment désulfurer des essences issues d'unités de craquage catalytique par un procédé consistant à convertir les composés soufrés en composés soufrés plus lourds à l'aide d'un agent d'alkylation en présence d'un catalyseur acide. L'agent d'alkylation inclus les oléfines ou les alcools. Toutefois, cette invention est décrite pour une application sur les essences de craquage catalytique et vise à alourdir les composés soufrés de type thiophène et méthylthiophène.The different hydrotreatment schemes for liquid hydrocarbon fractions from steam cracking units are described in the literature. For example, the patent application FR2858981 which describes a production scheme of different cuts from a steam cracking unit by the implementation of 3 distinct stages of hydrotreatment.
However, the existing or envisaged solutions consist exclusively in the implementation of hydrodesulphurization steps which require the presence of hydrogen in an expensive process and do not describe the possibility of treating one of the fractions resulting from the unit of steam cracking by a process based on the weighting of sulfur compounds on an acid catalyst.
Moreover, the desulfurization of hydrocarbon fractions by treatment with an acid catalyst is also widely described in the literature. For example, the patent US 6,048,451 describes how to desulphurize species from catalytic cracking by a process of converting the sulfur compounds to heavier sulfur compounds using an alkylating agent in the presence of an acid catalyst. The alkylating agent includes olefins or alcohols. However, this invention is described for application to catalytic cracking gasolines and is intended to increase the sulfur compounds of the thiophene and methylthiophene type.

Résumé de l'inventionSummary of the invention

La présente invention concerne un procédé de traitement d'une charge correspondant à une essence de pyrolyse comprenant :

  1. a) au moins une étape d'hydrogénation sélective appelée HD1 de la charge
  2. b) un fractionnement dans une ou plusieurs colonnes de distillation de l'effluent de l'étape a) afin de produire, au moins une coupe légère C5, une coupe intermédiaire C6 ou C6-C7 ou C6-C8 destinée à la production d'aromatiques, une coupe lourde C7+ ou C8+ ou C9+ destinée à la production d'essence
  3. c) au moins une étape d'hydrodésulfuration et d'hydrogénation profonde de la coupe intermédiaire appelée HD2
  4. d) au moins une étape d'alkylation de la coupe lourde C7+, C8+ ou C9+ on mélange avec une fraction de la coupe légère C5 consistant en un traitement sur catalyseur acide qui permet un alourdissement des composés soufrés
  5. e) au moins une étape de distillation de l'effluent de l'étape d) destinée à produire une fraction légère directement utilisable comme base essence à basse teneur en soufre, et une fraction lourde C11+ ou C12+ riche en composés soufrés et utilisée comme distillat moyen ou fuel.
The present invention relates to a method for treating a feedstock corresponding to a pyrolysis gasoline comprising:
  1. a) at least one step of selective hydrogenation called HD1 of the charge
  2. b) a fractionation in one or more distillation columns of the effluent of step a) in order to produce, at least one C5 light cut, an intermediate C6 or C6-C7 or C6-C8 cut intended for the production of aromatics, a heavy C7 + or C8 + or C9 + cut for the production of gasoline
  3. c) at least one step of hydrodesulfurization and deep hydrogenation of the intermediate cut called HD2
  4. d) at least one alkylation step of the C7 +, C8 + or C9 + heavy cut is mixed with a fraction of the C5 light cut consisting of an acidic catalyst treatment which allows the sulfur compounds to be weighed down;
  5. e) at least one step of distillation of the effluent of step d) intended to produce a light fraction which can be used directly as a low sulfur gasoline base, and a heavy fraction C11 + or C12 + rich in sulfur compounds and used as a distillate medium or fuel.

L'invention permet donc, en s'éloignant de la philosophie technique conventionnelle consistant à réduire le soufre des essences de pyrolyse par traitement sous hydrogène, de produire des essences de pyrolyse à faible teneur en soufre directement utilisables comme base essence et présentant un fort indice d'octane. De plus, les étapes a), b), c), et e) telles que décrites dans la présente demande sont souvent existantes dans les complexes pétrochimiques munis d'unités de vapocraquage. L'investissement nécessaire pour produire des essences de pyrolyse appauvries en soufre s'avère alors faible puisqu'il ne consiste qu'en la mise en oeuvre de l'étape d) d'alourdissement des composés soufrés.The invention therefore makes it possible, by departing from the conventional technical philosophy of reducing the sulfur of the pyrolysis gasolines by treatment under hydrogen, to produce low sulfur pyrolysis gasolines which can be used directly as a gasoline base and which have a high index. octane. In addition, steps a), b), c), and e) as described in this application are often present in petrochemical complexes equipped with steam cracking units. The investment required to produce pyrolysis gasolines depleted in sulfur is then weak since it consists only in the implementation of step d) of increasing the sulfur compounds.

Description détaillée de l'inventionDetailed description of the invention -étape a)-step a)

La charge, appelée essence de pyrolyse, est issue d'un ou plusieurs fractionnements d'essence de vapocraquage et correspond à une coupe dont la température d'ébullition est généralement comprise entre 0°C et 250°C, de préférence entre 10°C et 220°C. Typiquement, cette charge est constituée essentiellement de CS-C11 avec des traces (quelques % poids) de C3, C4, C12, C13, C14.
Cette charge subit généralement l'étape a) d'hydrogénation sélective et l'effluent de l'étape a) est envoyé à l'étape b).
On peut utiliser pour cette étape d'hydrogénation sélective, appelée HD1, un catalyseur métal noble (de type palladium notamment comme les catalyseurs LD265/LD465 commercialisés par la société Axens) ou un catalyseur métal non noble (de type nickel par exemple comme les catalyseurs LD341/LD441 commercialisés par la société Axens). L'étape a) consiste à mettre en contact la charge à traiter avec de l'hydrogène introduit en excès dans un ou plusieurs réacteurs contenant un catalyseur d'hydrogénation. Le débit d'hydrogène est ajusté afin d'en disposer en quantité suffisante pour hydrogéner théoriquement l'ensemble des dioléfines, des acétyléniques et des alkényl aromatiques et de maintenir un excès d'hydrogène en sortie de réacteur. Afin de limiter le gradient de température dans le réacteur, il peut être avantageux de recycler une fraction de l'effluent à l'entrée du réacteur. L'étape d'hydrogénation sélective HD1 aussi appelée étape d'hydrodédiénisation est bien connue de l'homme de l'art et est notamment décrite dans le livre Petrochemical Processes, Tome 1, Edition Technip, A. Chauvel et G. Lefebvre, pages 155-160 .
La température d'opération lors de l'étape a) est généralement comprise entre 50°C et 200°C, la vitesse horaire spatiale est comprise entre 1 h-1 et 6 h-1 et la pression est comprise entre 1,0 MPa et 4,0 MPa.The charge, called pyrolysis gasoline, is derived from one or more fractionations of steam cracking gasoline and corresponds to a section whose boiling point is generally between 0 ° C. and 250 ° C., preferably between 10 ° C. and 220 ° C. Typically, this feed consists essentially of CS-C11 with traces (a few wt%) of C3, C4, C12, C13, C14.
This charge generally undergoes the selective hydrogenation step a) and the effluent from step a) is sent to step b).
It is possible to use for this selective hydrogenation step, called HD1, a noble metal catalyst (palladium type in particular, such as the LD265 / LD465 catalysts marketed by the company Axens) or a non-noble metal catalyst (of the nickel type, for example as catalysts). LD341 / LD441 marketed by the company Axens). Step a) consists in bringing the charge to be treated into contact with hydrogen introduced in excess into one or more reactors containing a hydrogenation catalyst. The hydrogen flow rate is adjusted in order to dispose of it in sufficient quantity to theoretically hydrogenate all the diolefins, acetylenics and alkenyl aromatics and to maintain an excess of hydrogen at the reactor outlet. In order to limit the temperature gradient in the reactor, it may be advantageous to recycle a fraction of the effluent at the reactor inlet. The selective hydrogenation step HD1, also known as the hydrodenialization step, is well known to those skilled in the art and is described in particular in the book Petrochemical Processes, Volume 1, Technip Edition, A. Chauvel and G. Lefebvre, pages 155-160 .
The operating temperature during step a) is generally between 50 ° C. and 200 ° C., the space hourly speed is between 1 h -1 and 6 h -1 and the pressure is between 1.0 MPa. and 4.0 MPa.

-étape b)-step b)

C'est une étape de fractionnement dans une ou plusieurs colonnes de distillation de la charge ou de l'effluent de l'étape a) afin de produire, au moins une coupe légère constituée essentiellement de C5, une coupe intermédiaire constituée essentiellement de C6 ou C6-C7 ou C6-C8 destinée typiquement à la production d'aromatiques et une coupe lourde constituée essentiellement de C7+ ou C8+ ou C9+ destinée typiquement à la production d'essence.It is a fractionation step in one or more distillation columns of the feedstock or the effluent of step a) in order to produce at least one light cut consisting essentially of C5, an intermediate cut consisting essentially of C6 or C6-C7 or C6-C8 typically for the production of aromatics and a heavy cut consisting essentially of C7 + or C8 + or C9 + typically for the production of gasoline.

Selon un mode préférée de l'invention, la charge subit deux distillations successives afin de produire les 3 coupes. La première distillation conduit à une coupe légère constituée essentiellement de C5 et une coupe C6+. La coupe C6+ est envoyé à une deuxième colonne de distillation qui conduit à une coupe intermédiaire constituée essentiellement de C6 ou C6-C7 ou C6-C8 destinée à la production d'aromatiques et une coupe lourde constituée essentiellement de C7+ ou C8+ ou C9+ destinée à la production d'essence.According to a preferred embodiment of the invention, the feedstock undergoes two successive distillations in order to produce the 3 cuts. The first distillation results in a light cut consisting essentially of C5 and a C6 + cut. The C6 + cut is sent to a second distillation column which leads to an intermediate cut consisting essentially of C6 or C6-C7 or C6-C8 for the production of aromatics and a heavy cut consisting essentially of C7 + or C8 + or C9 + intended for the production of gasoline.

Selon un autre mode de réalisation, la charge passe tout d'abord par une première distillation afin d'obtenir une coupe légère constituée essentiellement de C5 et une coupe C6+ qui est envoyée à l'étape a). L'effluent de l'étape a) subit alors une distillation de manière à obtenir une coupe intermédiaire constituée essentiellement de C6 ou C6-C7 ou C6-C8 destinée à la production d'aromatiques et une coupe lourde constituée essentiellement de C7+ ou C8+ ou C9+ destinée à la production d'essence. La coupe intermédiaire est alors envoyé à l'étape c) d'hydrodésulfuration et d'hydrogénation profonde tandis que le coupe lourde est envoyé à l'étape d) d'alkylation. L'effluent de l'étape d) d'alkylation est alors envoyé à l'étape e) de distillation.According to another embodiment, the feedstock firstly passes through a first distillation in order to obtain a light cut consisting essentially of C5 and a C6 + cut which is sent to step a). The effluent of step a) then undergoes distillation so as to obtain an intermediate cut consisting essentially of C6 or C6-C7 or C6-C8 intended for the production of aromatics and a heavy cut consisting essentially of C7 + or C8 + or C9 + for the production of gasoline. The intermediate cut is then sent to step c) hydrodesulphurization and deep hydrogenation while the heavy cut is sent to step d) alkylation. The effluent of the alkylation step d) is then sent to the distillation step e).

-étape c)-step c)

C'est une étape, appelée HD2, d'hydrodésulfuration et d'hydrogénation profonde de la coupe intermédiaire. L'étape c) consiste à mettre en contact la coupe intermédiaire à traiter avec de l'hydrogène dans un ou plusieurs réacteurs contenant du catalyseur d'hydrogénation et d'hydrodésulfuration. Cette étape est également bien connue de l'homme de l'art et est notamment décrite dans le livre Petrochemical Processes, Tome 1, Edition Technip, A. Chauvel et G. Lefebvre, page 160 .This is a step, called HD2, hydrodesulphurization and deep hydrogenation of the intermediate cut. Step c) comprises contacting the intermediate cut to be treated with hydrogen in one or more reactors containing hydrogenation and hydrodesulfurization catalyst. This step is also well known to those skilled in the art and is particularly described in the book Petrochemical Processes, Volume 1, Technip Edition, A. Chauvel and G. Lefebvre, page 160 .

La température d'opération lors de l'étape c) est généralement comprise entre 220°C et 380°C, la vitesse horaire spatiale est comprise entre 1 h-1 et 6 h-1 et la pression est comprise entre 1,0 MPa et 4,0 MPa.
On peut par exemple utiliser un enchaînement des catalyseurs LD145 et HR406 commercialisés par la société Axens pour réaliser cette étape c).The operating temperature during stage c) is generally between 220 ° C. and 380 ° C., the space hourly speed is between 1 h -1 and 6 h -1 and the pressure is between 1.0 MPa. and 4.0 MPa.
One can for example use a sequence of LD145 and HR406 catalysts marketed by Axens to achieve this step c).

-étape d)-step d)

L'étape d) d'alkylation est une étape de traitement de la coupe lourde C7+, C8+ ou C9+ on mélange avec une fraction de la coupe légère C5 consistant en un traitement sur catalyseur acide qui permet de désulfurer la fraction de la dite coupe bouillant dans l'essence sans apport d'hydrogène par un alourdissement des composés soufrés.La charge traitée dans l'étape d) dite d'alkylation est une fraction hydrocarbonée issue d'une unité de vapocraquage.
La charge correspond à une coupe C7+, C8+ ou C9+ prétraitée dans une unité d'hydrogénation HD1. L'unité HD1 mise en oeuvre dans l'étape a) est destinée à hydrogéner sélectivement les dioléfines, les acétyléniques et une fraction des alkénylaromatiques. La charge est généralement un mélange constitué de composés oléfiniques, aromatiques, paraffiniques et naphténiques ainsi que de soufre à hauteur de 20 ppm poids à 1000 pm poids.The alkylation step d) is a step of treatment of the C7 +, C8 + or C9 + heavy cut, and is mixed with a fraction of the C5 light cut consisting of an acid catalyst treatment which makes it possible to desulphurize the fraction of the said boiling cut. in gasoline without the addition of hydrogen by increasing the sulfur compounds. The feedstock treated in the alkylation step d) is a hydrocarbon fraction derived from a steam cracking unit.
The charge corresponds to a C7 +, C8 + or C9 + cut pretreated in a hydrogenation unit HD1. The unit HD1 used in step a) is intended to selectively hydrogenate diolefins, acetylenes and a fraction of the alkenylaromatiques. The filler is generally a mixture of olefinic, aromatic, paraffinic and naphthenic compounds as well as sulfur up to 20 ppm by weight at 1000 pm weight.

L'étape d) d'alkylation est réalisée dans la section d'alkylation qui peut comprendre un ou plusieurs réacteurs.
Le principal objectif de l'étape d) est d'alourdir les composés soufrés, par addition de mono-oléfines présentes dans la charge. Les composés soufrés susceptibles de réagir sont les composés thiophèniques de type alkylthiophène, et dans une moindre mesure des composés de type mercaptans. Ces réactions n'impliquent aucune transformation des composés aromatiques car ces composés présentent une réactivité beaucoup plus faible que les composés oléfiniques et soufrés et ne sont donc pas transformés, ce qui est favorable au maintient de l'indice d'octane.
De façon surprenante, il a été découvert qu'il était possible d'alkyler les alkylthiophènes dont les groupements alkyles comportent 1 à 4 atomes de carbone, notamment les alkylthiophènes de type ethylthiophène, diméthylthiophène, propylthiophène et butylthiophène, par des mono-oléfines comprenant 7 atomes de carbone ou plus et des alkenyl aromatiques. Toutefois, la réactivité des oléfines longues étant plus faible que la réactivité des oléfines courtes, il peut être avantageux de mélanger à la charge un flux contenant des butènes ou pentènes.The alkylation step d) is carried out in the alkylation section which may comprise one or more reactors.
The main objective of step d) is to increase the sulfur compounds, by adding mono-olefins present in the feedstock. Sulfur compounds that can react are thiophene compounds of alkylthiophene type, and to a lesser extent mercaptan type compounds. These reactions do not involve any transformation of the aromatic compounds because these compounds have a much lower reactivity than the olefinic and sulfur compounds and are therefore not transformed, which is favorable to maintaining the octane number.
Surprisingly, it has been discovered that it is possible to alkylate alkylthiophenes whose alkyl groups contain 1 to 4 carbon atoms, in particular alkylthiophenes of the ethylthiophene, dimethylthiophene, propylthiophene and butylthiophene type, with monoolefins comprising 7 or more carbon atoms and aromatic alkenyls. However, since the reactivity of the long olefins is lower than the reactivity of the short olefins, it may be advantageous to mix a feed containing butenes or pentenes with the feedstock.

L'étape d) d'alkylation consiste généralement à mettre en contact la fraction à traiter avec un catalyseur acide solide dans des conditions de débit, température et pression choisies pour promouvoir l'addition des mono-oléfines et alkénylaromatiques sur les composés soufrés. Les composés soufrés lourds ainsi formés présentent généralement une température d'ébullition supérieure au point final typique de l'essence, c'est-à-dire supérieur à 220°C. Typiquement, ils peuvent donc être séparés de l'essence par simple distillation.
Le catalyseur mis en oeuvre dans l'étape d) dite d'alkylation est de préférence un catalyseur acide solide. Tout catalyseur susceptible de promouvoir l'addition de composés hydrocarbonés insaturés sur les composés soufrés peut être utilisé dans la présente invention. On utilise généralement les zéolithes, les argiles, les silices fonctionnalisées, les silico-aluminates présentant une acidité ou les supports greffés de groupes fonctionnels acides ou encore les résines échangeuses d'ions acides.
De préférence, on utilise des résines échangeuses d'ions acides , de façon très préférée des résines échangeuses d'ions acides polymériques telles que les résines acides sulfoniques. Pour cette application les résines commercialisées par la société Rhom&Haas sons le nom d'Amberlyst15, Amberlyst35 ou Amberlyst 36 peuvent être utilisées. On peut également utiliser la résine TA801 commercialisée par la société Axens.
Il est également possible d'utiliser des catalyseurs à base d'acide phosphorique tels que décrit dans le brevet US 6,736,963 obtenus par comalaxage d'acide phosphorique et de silice amorphe de type kieselguhr.
Outre les acides supportés, il est également possible, tout en restant dans le cadre de l'invention, d'utiliser des acides à base d'oxydes inorganiques incluant les alumines, les silice, les silice alumines et plus particulièrement les zéolithes telles que les zéolithes faujasites, mordenites, L, omega, X, Y, beta, ZSM-3, ZSM-4, ZSM-5, ZSM-18 et ZSM-20. Les catalyseurs peuvent également consistés en une mixture de différents acides de Lewis (par exemple, BF4, BC13, SbF5 et AlCl3) avec une oxyde métallique non zéolithique tel que la silice, l'alumine, les silice-alumines.The alkylation step d) generally consists in bringing the fraction to be treated into contact with a solid acid catalyst under conditions of flow, temperature and pressure chosen to promote the addition of the monoolefins and alkenylaromatic compounds to the sulfur compounds. The heavy sulfur compounds thus formed generally have a boiling point higher than the typical end point of the gasoline, that is to say higher than 220 ° C. Typically, they can be separated from gasoline by simple distillation.
The catalyst employed in the alkylation step d) is preferably a solid acid catalyst. Any catalyst capable of promoting the addition of unsaturated hydrocarbon compounds to the sulfur compounds can be used in the present invention. Zeolites, clays, functionalized silicas, silico-aluminates having acidity or grafted supports of acidic functional groups or acidic ion exchange resins are generally used.
Preferably, acidic ion exchange resins are used, most preferably polymeric acidic ion exchange resins such as sulfonic acid resins. For this application the resins marketed by the company Rhom & Haas sounds the name of Amberlyst15, Amberlyst35 or Amberlyst 36 can be used. It is also possible to use the TA801 resin marketed by the company Axens.
It is also possible to use catalysts based on phosphoric acid as described in the patent US 6,736,963 obtained by the comalaxing of phosphoric acid and amorphous silica of kieselguhr type.
In addition to the supported acids, it is also possible, while remaining within the scope of the invention, to use acids based on inorganic oxides, including aluminas, silica, silica aluminas and more particularly zeolites such as zeolites faujasites, mordenites, L, omega, X, Y, beta, ZSM-3, ZSM-4, ZSM-5, ZSM-18 and ZSM-20. The catalysts can also consist of a mixture of different acids of Lewis (e.g. BF4, BC13, SbF5 and AlCl3) with a non-zeolitic metal oxide such as silica, alumina, silica-aluminas.

La température d'opération est généralement ajustée en fonction du catalyseur choisi, afin d'atteindre le taux de transformation des composés soufrés désiré. La température est généralement comprise entre 30°C et 300°C, et de préférence, entre 40°C et 250°C.
Dans l'hypothèse où le catalyseur utilisé est une résine échangeuse d'ions acide, la température n'excède pas 200°C et de façon préférée 150°C afin de préserver l'intégrité du catalyseur.
Dans le cas où le catalyseur utilisé est un acide phosphorique sur silice, la température est supérieure à 100°C et inférieure à 250°C, de préférence supérieure à 140°C et inférieure à 220°C.The operating temperature is generally adjusted according to the chosen catalyst, in order to reach the conversion rate of the desired sulfur compounds. The temperature is generally between 30 ° C and 300 ° C, and preferably between 40 ° C and 250 ° C.
Assuming that the catalyst used is an acidic ion exchange resin, the temperature does not exceed 200 ° C and preferably 150 ° C to preserve the integrity of the catalyst.
In the case where the catalyst used is a phosphoric acid on silica, the temperature is greater than 100 ° C and less than 250 ° C, preferably greater than 140 ° C and less than 220 ° C.

Le volume de catalyseur mis en oeuvre est tel que le rapport entre le débit volumique de charge à traiter et le volume catalytique encore appelé vitesse horaire spatiale est typiquement compris entre 0,05 h-1 et 5 h-1, de préférence entre 0,07 h-1 et 3 h-1 et de façon très préférée entre 0,1 h-1 et 2 h-1.The volume of catalyst used is such that the ratio between the volume flow rate of the feedstock to be treated and the catalytic volume, also called the space hourly speed, is typically between 0.05 h -1 and 5 h -1 , preferably between 0, 07 h -1 and 3 h -1 and very preferably between 0.1 h -1 and 2 h -1 .

La pression est généralement ajustée afin de maintenir le mélange réactionnel en phase liquide. Typiquement, la pression est comprise entre 1,0 MPa et 4,0 MPa, de préférence comprise entre 1,5 MPa et 4,0 MPa.The pressure is generally adjusted to maintain the reaction mixture in the liquid phase. Typically, the pressure is between 1.0 MPa and 4.0 MPa, preferably between 1.5 MPa and 4.0 MPa.

L'étape d'alkylation d) est typiquement mise en oeuvre dans au moins un réacteur cylindrique à lit fixe. Toutefois, il est préférable de disposer de plusieurs réacteurs opérés en série ou en parallèle afin de garantir une opération continue malgré la désactivation du catalyseur. Selon un mode préféré de réalisation de l'invention, l'étape d'alkylation est réalisée dans 2 réacteurs identiques et connectés entre eux, l'un étant en opération pendant que l'autre est à l'arrêt et chargé de catalyseur frais prêt à être utilisé. Ce dispositif permet notamment d'opérer l'unité continûment pendant les phases de remplacement ou pendant les phases de régénération in situ du catalyseur usé.The alkylation step d) is typically carried out in at least one fixed bed cylindrical reactor. However, it is preferable to have several reactors operated in series or in parallel in order to guarantee continuous operation despite deactivation of the catalyst. According to a preferred embodiment of the invention, the alkylation step is carried out in two identical reactors connected to each other, one being in operation while the other is stopped and loaded with fresh ready catalyst. to be used. This device makes it possible in particular to operate the unit continuously during the replacement phases or during the regeneration phases in situ of the spent catalyst.

Selon un autre mode de réalisation de l'invention, l'étape d'alkylation est réalisée dans 3 réacteurs qui peuvent être opérés en parallèle ou en série. Dans ce dernier cas, la charge alimente successivement deux réacteurs, un premier contenant un catalyseur partiellement usé, et le second contenant du catalyseur frais. Le troisième réacteur est laissé à l'arrêt, chargé de catalyseur frais et prêt à être utilisé. Lorsque le catalyseur du premier réacteur est désactivé, le réacteur est arrêté, le second réacteur est alors opéré en première position et le troisième réacteur initialement à l'arrêt est opéré en seconde position. Le premier réacteur arrêté peut alors être déchargé et son catalyseur remplacé par un lot de catalyseur frais.According to another embodiment of the invention, the alkylation step is carried out in 3 reactors which can be operated in parallel or in series. In the latter case, the feed successively feeds two reactors, one containing a partially spent catalyst, and the second containing fresh catalyst. The third reactor is left stationary, charged with fresh catalyst and ready for use. When the catalyst of the first reactor is deactivated, the reactor is stopped, the second reactor is then operated in first position and the third reactor initially stopped is operated in second position. The first stopped reactor can then be discharged and its catalyst replaced with a batch of fresh catalyst.

En parallèle des réactions d'alkylation des composés soufrés, il peut se produire, dans le réacteur, des réactions de dimérisation des oléfines, entraînant un alourdissement de la fraction hydrocarbonée traitée. Toutefois, les composés de type aromatique sont très peu voire même non convertis dans le réacteur. Généralement la conversion des aromatiques est inférieure à 10%.de préférence à 5%, ce qui permet de préserver l'indice d'octane de la coupe. Les réactions d'alkylation des composés soufrés et de dimérisation des oléfines présentent un caractère exothermique, c'est-à-dire qu'elles sont favorisées à basse température et dégagent de la chaleur. Afin de limiter le dégagement de chaleur, et d'atteindre des températures excessives dans le réacteur, il peut être avantageux de recycler une fraction du ou des effluents du ou des réacteurs, à l'entrée du ou des réacteurs. Le taux de recyclage, défini comme le débit d'effluent recyclé divisé par le débit de charge fraîche est typiquement compris entre 0,2 et 4 et de préférence compris entre 0,5 et 2.In parallel with the alkylation reactions of the sulfur compounds, olefin dimerization reactions can occur in the reactor, resulting in an increase in the treated hydrocarbon fraction. However, the aromatic compounds are very little or not even converted in the reactor. Generally the conversion of aromatics is less than 10%, preferably 5%, which allows to preserve the octane number of the cut. The alkylation reactions of sulfur compounds and of olefin dimerization are exothermic, that is, they are favored at low temperature and give off heat. In order to limit the release of heat, and to reach excessive temperatures in the reactor, it may be advantageous to recycle a fraction of the effluent (s) of the reactor (s) at the inlet of the reactor (s). The recycling rate, defined as the recycled effluent flow divided by the fresh feed rate is typically between 0.2 and 4 and preferably between 0.5 and 2.

Dans le cas particulier où le catalyseur utilisé est une résine échangeuse d'ions, il peut être avantageux de mettre en oeuvre le catalyseur en lit dit expansé. Pour cela, la charge est généralement injectée par le bas du réacteur, à une vitesse linéaire suffisante pour entraîner une mise en suspension des billes de catalyseur. Ce type de mise en oeuvre présente l'avantage de limiter le gradient de températures dans le réacteur, c'est-à-dire la différence de température entre la sortie et l'entrée du réacteur, et d'assurer une bonne distribution de la charge hydrocarbonée liquide et une bonne homogénéité thermique dans le réacteur.In the particular case where the catalyst used is an ion exchange resin, it may be advantageous to use the so-called expanded bed catalyst. For this, the charge is generally injected through the bottom of the reactor, at a linear velocity sufficient to cause suspension of the catalyst beads. This type of implementation has the advantage of limiting the temperature gradient in the reactor, that is to say the temperature difference between the outlet and the inlet of the reactor, and of ensuring a good distribution of the liquid hydrocarbon feedstock and good thermal homogeneity in the reactor.

Selon un mode préféré, un système d'appoint/soutirage du catalyseur peut être rajouté au réacteur afin de soutirer en continu du catalyseur usé et réaliser un appoint de catalyseur frais.According to a preferred embodiment, a system for supplementing / withdrawing the catalyst can be added to the reactor in order to continuously withdraw spent catalyst and make a supplement of fresh catalyst.

Selon le mode préféré de réalisation de l'invention, on utilise un catalyseur de type résine échangeuse d'ions acide car c'est un catalyseur qui s'avère très actif et qui permet d'opérer le réacteur à une faible température, c'est-à-dire à une température généralement inférieure à 200°C, ce qui est permet de limiter la formation de gommes et polymères qui sont des produits facilement formés par réaction de condensation des composés insaturés de type polyoléfines ou alkénylaromatiques dans les fractions intermédiaires de vapocraquage. Ainsi, la vitesse spatiale (VVH) est ajustée afin de permettre une opération à la température la plus basse possible, compatible avec les performances recherchées. Typiquement, on peut opérer le réacteur à une VVH comprise entre 0,1 h-1 et 2 h-1 et une température inférieure à 80°C. Lorsque le catalyseur se désactive, il est nécessaire d'augmenter progressivement la température pour maintenir les performances. La température peut alors être augmentée progressivement jusqu'à atteindre généralement 150°C voire 200°C maximum.According to the preferred embodiment of the invention, an acid ion exchange resin catalyst is used because it is a catalyst which proves to be very active and which makes it possible to operate the reactor at a low temperature. that is to say at a temperature generally below 200 ° C, which is to limit the formation of gums and polymers which are easily formed products by condensation reaction of unsaturated compounds of polyolefin or alkenylaromatic type in the intermediate fractions of steam cracking. Thus, the space velocity (VVH) is adjusted to allow operation at the lowest temperature possible, compatible with the desired performance. Typically, the reactor can be operated at a VVH between 0.1 hr-1 and 2 hr-1 and a temperature below 80 ° C. When the catalyst deactivates, it is necessary to gradually increase the temperature to maintain the performance. The temperature can then be increased gradually until it reaches generally 150 ° C. or even 200 ° C. maximum.

Le catalyseur usé peut subir un traitement de réjuvénation soit dans le réacteur lorsque celui ci est isolé du circuit soit en dehors du réacteur lorsque qu'un système de soutirage et appoint du réacteur a été prévu. En fonction du type de catalyseur utilisé, on peut avoir recours à au moins un des traitements suivants :

  • lavage par composés oxygénés
  • lavage par composés aromatiques
  • stripage par gaz (azote, hydrogène, vapeur)
  • combustion par air dilué
The spent catalyst may undergo a rejuvenation treatment either in the reactor when it is isolated from the circuit or outside the reactor when a withdrawal system and reactor booster has been provided. Depending on the type of catalyst used, at least one of the following treatments may be used:
  • oxygenated compounds washing
  • aromatic washing
  • gas stripping (nitrogen, hydrogen, steam)
  • diluted air combustion

Une fraction de la coupe légère C5 est injectée dans la coupe lourde C7+, C8+ ou C9+ puis envoyé à l'étape d'alkylation. Ce mélange permet d'augmenter la quantité de mono-oléfines réactives et de favoriser ainsi la conversion des composés soufrés.A fraction of the C5 light cut is injected into the C7 +, C8 + or C9 + heavy cut and then sent to the alkylation step. This mixture makes it possible to increase the amount of reactive monoolefins and thus to promote the conversion of the sulfur compounds.

-étape e)-step e)

C'est une étape de distillation de l'effluent de l'étape d) destinée à produire une fraction légère directement utilisable comme base essence, et une fraction lourde C11+ ou C12+ riche en composés soufrés et utilisée comme distillat moyen ou fuel. La fraction légère présente un point final généralement inférieur à 230°C et de préférence inférieur à 220°C.It is a step of distillation of the effluent of step d) intended to produce a light fraction that can be used directly as a gasoline base, and a C11 + or C12 + heavy fraction rich in sulfur compounds and used as an average or fuel distillate. The light fraction has an end point generally less than 230 ° C and preferably less than 220 ° C.

Description des figuresDescription of figures - Figure 1- Figure 1

La figure 1 présente un mode de réalisation préféré de l'invention. La charge est alimentée par la ligne 1 et traitée dans une unité d'hydrogénation sélective HD1 pour réaliser notamment une dédiénisation et réduction d'alkenyl aromatiques préalable. La charge dédiénisée circule par la ligne 2 et est fractionnée dans une colonne de distillation 3 en une fraction C5 circulant par la ligne 4, typiquement recyclée au vapocraquage ou utilisée comme base essence, et une fraction C6+ circulant dans la ligne 5. Cette coupe C6+ est fractionnée dans une colonne de distillation 7 en une fraction C6-Cn (où n=7 ou 8) circulant dans la ligne 8, et une fraction Cn+1+ circulant dans la ligne 9. La coupe C6-Cn alimente une unité d'hydrotraitement HD2 qui réalise une désulfuration poussée de la coupe C6-Cn et une hydrogénation profonde des mono-oléfines. On peut par exemple utiliser les catalyseurs LD145/HR406 commercialisés par la société Axens pour réaliser cette étape. La coupe C6-Cn traitée, évacuée par la ligne 10 peut avoir par exemple moins de 1 ppm poids de soufre et moins de 50 ppm poids de mono-oléfines. On cherche généralement à minimiser l'hydrogénation des aromatiques dans cette coupe afin de maximiser leur récupération ultérieure pour des applications pétrochimiques. La coupe Cn+1+ sortant du fond de la colonne 7 par la ligne 9 alimente la section ALK dite section d'alkylation pour produire une coupe alkylée récupérée par la ligne 11. Une fraction de la coupe C5 issue de la colonne 3 est injectée par l'intermédiaire de la ligne 6 dans la charge de la section d'alkylation afin d'augmenter la quantité d'oléfines réactives et de favoriser ainsi la conversion des composés soufrés. La coupe produite dans la section ALK d'alkylation est envoyée par la ligne 11 vers une colonne de distillation 12 pour produire, en tête, une coupe Cn+1-C12 récupérée par la ligne 13 appauvrie en soufre destinée à être utilisée comme base essence, et en fond une coupe C12+ récupérée par la ligne 14 qui peut être utilisée comme fuel domestique et dans laquelle se concentrent les composés soufrés alkylés dans la section d'alkylation. La coupe Cn+1-C12 récupérée par la ligne 13 contient généralement moins de 100 ppm de soufre voire moins de 50 pm de soufre ou bien dans l'objectif de la production d'essences à très faible teneur en soufre, moins de 10 ppm de soufre.The figure 1 presents a preferred embodiment of the invention. The feedstock is fed via line 1 and treated in a selective hydrogenation unit HD1 to carry out in particular a prior art alkenyl reduction and dedenization. The dedenized charge flows through line 2 and is fractionated in a distillation column 3 into a fraction C5 flowing through line 4, typically recycled to steam cracking or used as a gasoline base, and a C6 + fraction flowing in line 5. This C6 + cut is fractionated in a distillation column 7 into a C6-C n fraction (where n = 7 or 8) circulating in the line 8, and a C n + 1 + fraction flowing in the line 9. The C6-C n fraction feeds a hydrotreating unit HD2 which performs a thorough desulfurization of the C6-Cn cut and a deep hydrogenation of mono-olefins. For example, the LD145 / HR406 catalysts marketed by Axens can be used to carry out this step. The treated C6-Cn cut evacuated via line 10 may have, for example, less than 1 ppm by weight of sulfur and less than 50 ppm by weight of mono-olefins. It is generally sought to minimize the hydrogenation of the aromatics in this section in order to maximize their subsequent recovery for petrochemical applications. The cut C n + 1 + leaving the bottom of the column 7 by the line 9 feeds the section ALK said alkylation section to produce an alkylated cut recovered by the line 11. A fraction of the C5 cut from column 3 is injected via line 6 into the charge of the alkylation section to increase the amount of reactive olefins and thereby promote the conversion of sulfur compounds. The cut produced in the alkylation section ALK is sent via line 11 to a distillation column 12 to produce, at the top, a C n + 1 -C 12 cut recovered by the sulfur-depleted line 13 for use as a base gasoline, and in bottom a C12 + cut recovered by line 14 which can be used as domestic fuel and in which the alkylated sulfur compounds are concentrated in the alkylation section. The C n + 1 -C 12 cut recovered by line 13 generally contains less than 100 ppm of sulfur or even less than 50 pm of sulfur or for the purpose of the production of very low sulfur species, less than 10 ppm of sulfur.

- Figure 2- Figure 2

La figure 2 détaille un mode de réalisation préféré de l'étape d'alkylation d). La section d'alkylation est constituée de deux réacteurs R1 et R2 qui peuvent être opérés en parallèle. La fraction Cn+1 (où n=7 ou 8) récupérée de la colonne de distillation 7 par la ligne 9 est mélangée à une fraction de la coupe C5 par la ligne 6. Le mélange ainsi constitué (ligne 9a) est envoyé vers le réacteur R1 par la ligne 9b et le produit d'alkylation est récupéré par la ligne 9d. Pendant cette phase le réacteur R2 est chargé de catalyseur frais et actif et laissé à l'arrêt. Lorsque le catalyseur contenu dans le réacteur R1 est désactivé, le réacteur R1 est arrêté et la charge à traiter est envoyée vers le réacteur R2 par la ligne 9c. Le produit d'alkylation est récupéré par la ligne 9e. Pendant ce temps, le catalyseur contenu dans le réacteur R1 est déchargé et remplacé par une charge de catalyseur frais. Ce dispositif particulier permet de maintenir une opération continue même lorsque le catalyseur est désactivé.The figure 2 details a preferred embodiment of the alkylation step d). The alkylation section consists of two reactors R1 and R2 which can be operated in parallel. The fraction C n + 1 (where n = 7 or 8) recovered from distillation column 7 via line 9 is mixed with a fraction of section C5 via line 6. The mixture thus formed (line 9a) is sent to the reactor R1 via line 9b and the alkylation product is recovered via line 9d. During this phase the reactor R2 is charged with fresh and active catalyst and left stationary. When the catalyst contained in the reactor R1 is deactivated, the reactor R1 is stopped and the feedstock to be treated is sent to the reactor R2 via the line 9c. The alkylation product is recovered via line 9e. During this time, the catalyst contained in the reactor R1 is discharged and replaced with a fresh catalyst charge. This particular device makes it possible to maintain a continuous operation even when the catalyst is deactivated.

ExemplesExamples

L'exemple suivant explicite, de façon non limitative, des catalyseurs et conditions opératoires utilisables dans le procédé selon l'invention.The following example explains, in a nonlimiting manner, catalysts and operating conditions that can be used in the process according to the invention.

On fractionne des effluents de vapocraquage de naphta dans une installation de traitement de ces effluents, comprenant une distillation primaire, pour produire, notamment une coupe essence de pyrolyse α, comprenant essentiellement des C5 et des hydrocarbures plus lourds jusqu'à un point final ASTM de 210°C.Naphtech steam-cracking effluents are fractionated in a treatment plant for these effluents, comprising a primary distillation, to produce, in particular, an α-pyrrolysis gasoline cut, essentially comprising C5 and heavier hydrocarbons up to an ASTM endpoint of 210 ° C.

Cette coupe essence de pyrolyse α possède les caractéristiques suivantes :
- Teneur en soufre : 200 ppm poids
- Composition de la coupe essence de pyrolyse α (% poids) C3 C4 C5 C6 C7 C8 C9 C10 C11 C12+ Total n-paraffins 0,0 0,1 3,6 1,3 0,2 0,0 0,0 0,0 0,0 0,0 5,2 i-paraffins 0,0 2,7 1,4 0,3 0,4 0,1 0,0 0,0 0,0 4,9 mono- olefins 0,2 0,6 5,3 1,7 0,7 1,0 0,4 0,3 1,0 0,9 12,1 diolefins 0,0 1,1 10,3 3,9 3,4 1,8 0,1 20,8 naphthenes 0,5 1,3 0,5 0,1 0,0 0,0 0,0 0,0 2,5 aromatics 26,6 11,8 4,2 2,0 1,9 0,7 0,1 47,3 alkenyls aromatiques 3,5 3,1 0,5 0,0 0,0 7,1 Total 0,2 1,8 22,4 36,4 13,5 9,2 5,6 6,2 3,6 1,1 100,0 This essence cut of pyrolysis α has the following characteristics:
- Sulfur content: 200 ppm by weight
- Composition of the pyrolysis gasoline fraction α (% by weight) C3 C4 C5 C6 C7 C8 C9 C10 C11 C12 + Total n-paraffins 0.0 0.1 3.6 1.3 0.2 0.0 0.0 0.0 0.0 0.0 5.2 i-paraffins 0.0 2.7 1.4 0.3 0.4 0.1 0.0 0.0 0.0 4.9 monoolefins 0.2 0.6 5.3 1.7 0.7 1.0 0.4 0.3 1.0 0.9 12.1 diolefins 0.0 1.1 10.3 3.9 3.4 1.8 0.1 20.8 naphthenes 0.5 1.3 0.5 0.1 0.0 0.0 0.0 0.0 2.5 aromatics 26.6 11.8 4.2 2.0 1.9 0.7 0.1 47.3 aromatic alkenyls 3.5 3.1 0.5 0.0 0.0 7.1 Total 0.2 1.8 22.4 36.4 13.5 9.2 5.6 6.2 3.6 1.1 100.0

Cette coupe essence de pyrolyse est traitée selon le schéma de procédé décrit à la figure 1.This essence pyrolysis cut is treated according to the process scheme described in figure 1 .

Catalyseur et conditions opératoires de la première étape d'hydrotraitement : HD1Catalyst and operating conditions of the first hydrotreatment step: HD1

Le catalyseur utilisé pour l'étape HD1 est constitué de 0,3% poids de palladium déposé sur un support d'alumine poreuse. Le catalyseur est disposé en deux lits dans un réacteur avec un dispositif permettant d'injecter un fluide destiné notamment à refroidir le mélange réactionnel entre les deux lits.
Les conditions opératoires sont les suivantes :

  • Température de sortie réacteur : 110°C
  • Pression de sortie réacteur : 3,0 MPa
  • VVH (vitesse horaire spatiale) : 2,4 h-1
Taux d'hydrogène (gaz total entrée réacteur) : 90 Nm3 d'hydrogène par m3 de charge.The catalyst used for step HD1 consists of 0.3% by weight of palladium deposited on a porous alumina support. The catalyst is arranged in two beds in a reactor with a device for injecting a fluid intended in particular to cool the reaction mixture between the two beds.
The operating conditions are as follows:
  • Reactor outlet temperature: 110 ° C
  • Reactor output pressure: 3.0 MPa
  • VVH (space hourly velocity): 2.4 h-1
Hydrogen content (total reactor inlet gas): 90 Nm 3 of hydrogen per m 3 of charge.

Le produit ainsi hydrotraité est distillé afin de séparer les fractions C5, C6-C8 et C9+.The product thus hydrotreated is distilled to separate the fractions C5, C6-C8 and C9 +.

La fraction C9+ nommée fraction β présente les caractéristiques suivantes :

  • Intervalle de distillation ASTM : 145°C - 218°C
  • Densité : 0,9
  • Teneur en soufre : 300 ppm poids
  • Teneur en aromatiques : 58 % poids dont 1,0 % poids de diaromatiques
  • Teneur en mono-oléfines + paraffines + naphtènes: 37% poids
  • Teneur en dioléfines + alkenyl aromatiques : 5 % poids
The fraction C9 + named fraction β has the following characteristics:
  • Distillation range ASTM: 145 ° C - 218 ° C
  • Density: 0.9
  • Sulfur content: 300 ppm
  • Aromatic content: 58% by weight including 1.0% by weight of diaromatic
  • Content of mono-olefins + paraffins + naphthenes: 37% by weight
  • Content of diolefins + alkenyl aromatics: 5% by weight

Catalyseur et conditions opératoires de l'étape d'alkylationCatalyst and operating conditions of the alkylation step

Le catalyseur utilisé pour l'étape d'alkylation est le catalyseur acide TA801 commercialisé par la société Axens. Le catalyseur est disposé en un seul lit.
Les conditions opératoires sont les suivantes :

  • Température d'entrée du réacteur : 80°C
  • Pression de sortie réacteur : 3,0 MPa
  • VVH (vitesse horaire spatiale) : 0,25 h-1
The catalyst used for the alkylation step is the TA801 acid catalyst sold by the company Axens. The catalyst is arranged in a single bed.
The operating conditions are as follows:
  • Reactor inlet temperature: 80 ° C
  • Reactor output pressure: 3.0 MPa
  • VVH (hourly space velocity): 0.25 h-1

Le produit ainsi récupéré nommé essence γ présente les caractéristiques suivantes :

  • Intervalle de distillation ASTM : 145°C - 285°C
  • Densité : 0,92
  • Teneur en soufre : 300 ppm poids
  • Teneur en aromatiques : 57% poids dont 1 % de diaromatiques
  • Teneur en oléfines : 33% poids
The product thus recovered named gasoline γ has the following characteristics:
  • Distillation range ASTM: 145 ° C - 285 ° C
  • Density: 0.92
  • Sulfur content: 300 ppm
  • Aromatic content: 57% by weight including 1% diaromatic
  • Olefin content: 33% by weight

L'essence γ est ensuite distillée afin de récupérer une première fraction légère γ1 dont la gamme d'ébullition correspond à la coupe essence, et une fraction lourde γ2.Gasoline γ is then distilled in order to recover a first light fraction γ1 whose boiling range corresponds to the gasoline fraction, and a heavy fraction γ2.

Les caractéristiques de l'essence γ1 sont les suivantes :

  • Intervalle de distillation ASTM : 145°C - 220°C
  • Densité : 0,9
  • Teneur en soufre : 46 ppm poids
  • Teneur en aromatiques : 58% poids dont 1% de diaromatiques
  • Teneur en oléfines : 27% poids
The characteristics of gasoline γ1 are as follows:
  • Distillation range ASTM: 145 ° C - 220 ° C
  • Density: 0.9
  • Sulfur content: 46 ppm by weight
  • Aromatic content: 58% by weight including 1% diaromatic
  • Olefin content: 27% by weight

Le point final de l'essence γ1 peut être ajusté en fonction des spécifications essence de chaque pays.The end point of gasoline γ1 can be adjusted according to the essence specifications of each country.

Les caractéristiques de l'essence γ2 sont les suivantes :

  • Intervalle de distillation ASTM : 220°C - 285°C
  • Teneur en soufre : 1300 ppm poids
The characteristics of gasoline γ2 are as follows:
  • Distillation range ASTM: 220 ° C - 285 ° C
  • Sulfur content: 1300 ppm weight

L'essence γ1 peut être incorporée directement au pool essence à basse teneur en soufre.Gasoline γ1 can be incorporated directly into the low-sulfur gasoline pool.

L'essence γ2 peut être utilisée comme fuel domestique.Gasoline γ2 can be used as domestic fuel.

Claims (8)

  1. A method for treating a hydrocarbon steam cracking effluent corresponding to a cut having a boiling point temperature ranging between 0°C and 250°C, comprising:
    a) at least one stage of selective hydrogenation of the feed, referred to as HD1,
    b) fractionating in one or more distillation columns the effluent from stage a) in order to produce at least one light C5 cut, an intermediate C6 or C6-C7 or C6-C8 cut intended for aromatics production, a heavy C7+ or C8+ or C9+ cut intended for gasoline production,
    c) at least one stage of hydrodesulfurization and deep hydrogenation of the intermediate cut, referred to as HD2,
    d) at least one stage of alkylation of the heavy C7+, C8+ or C9+ cut mixed with a fraction of the light C5 cut, said stage being operated at a temperature that ranges between 30°C and 300°C, a hourly space velocity that ranges between 0.05 h-1 and 5 h-1, and a pressure that ranges between 1.0 MPa and 4.0 MPa, wherein the stage of alkylation consists of a treatment on a solid acid catalyst selected from the group consisting of acid ion-exchanging resins, zeolites, clays, functionalized silicas, silico-aluminates with an acidity and grafted supports of acid functional groups, said solid acid catalyst allowing weighting of the sulfur compounds
    e) at least one stage of distillation of the effluent from stage d), intended to produce a light fraction that can be directly used as a low-sulfur gasoline base, and a heavy C11+ or C12+ fraction rich in sulfur compounds and used as middle distillate or fuel oil.
  2. A method as claimed in claim 1, wherein the catalyst is selected from the group made up of acid ion-exchanging resins.
  3. A method as claimed in any one of the previous claims, wherein alkylation stage d) is carried out in several reactors operated in series or in parallel.
  4. A method as claimed in claim 3, wherein alkylation stage d) is carried out in two identical reactors connected to one another, one being in operation while the other is stopped and loaded with fresh catalyst ready for use.
  5. A method as claimed in any one of claims 3 or 4, wherein a fraction of the effluents of alkylation stage d) is recycled to the inlet of the alkylation reactors.
  6. A method as claimed in claim 2, wherein the catalyst is used in an expanded bed.
  7. A method as claimed in any one of claims 3, 4 or 5, wherein a catalyst addition/withdrawal system is added to the reactors of stage d) in order to continuously withdraw used catalyst and to have fresh catalyst make-up.
  8. A method as claimed in any one of the previous claims, wherein the catalyst(s) used for stage d) are subjected to a rejuvenation treatment either in the reactor when it is isolated from the circuit or outside the reactor when an addition/withdrawal system is provided.
EP08290204A 2007-03-14 2008-02-27 Method of desulphurating hydrocarbon fractions from steam cracking effluent Active EP1972678B1 (en)

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FR0701896A FR2913692B1 (en) 2007-03-14 2007-03-14 PROCESS FOR DESULFURIZING HYDROCARBONIC FRACTIONS RESULTING FROM VAPOCRACKING EFFLUENTS

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CN102234540B (en) * 2010-05-07 2013-09-11 中国石油化工集团公司 Hydrogenation method and apparatus for center fractions of pyrolysis gasoline
CN102234541B (en) * 2010-05-07 2013-07-17 中国石油化工集团公司 Energy-saving pyrolysis gasoline full-cut hydrogenation method and device
CN103074104B (en) * 2011-10-26 2015-11-25 中国石油化工股份有限公司 A kind of gasoline hydrodesulfurizationmethod method
EA026212B1 (en) * 2012-08-21 2017-03-31 Каталитик Дистиллейшн Текнолоджиз Selective hydrodesulfurization of fcc gasoline to below 10 ppm sulfur
US20150119613A1 (en) * 2013-10-25 2015-04-30 Uop Llc Pyrolysis gasoline treatment process
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FR3103822B1 (en) * 2019-12-02 2022-07-01 Ifp Energies Now METHOD FOR TREATMENT OF PYROLYSIS OILS FROM PLASTICS WITH A VIEW TO RECYCLING THEM IN A STEAM CRACKING UNIT
CN115948180B (en) * 2023-03-14 2023-05-23 新疆天利石化股份有限公司 Energy-saving and environment-friendly process for producing mixed aromatic hydrocarbon by cracking carbon nine and hydrogenation

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US7947166B2 (en) 2011-05-24
BRPI0800628B1 (en) 2017-03-14
BRPI0800628A (en) 2008-11-04
CN101265421B (en) 2013-03-27
FR2913692B1 (en) 2010-10-15
KR20080084746A (en) 2008-09-19
CN101265421A (en) 2008-09-17
FR2913692A1 (en) 2008-09-19
EP1972678A1 (en) 2008-09-24
SG146554A1 (en) 2008-10-30
US20080223753A1 (en) 2008-09-18
JP2008223027A (en) 2008-09-25
TW200902702A (en) 2009-01-16
TWI452129B (en) 2014-09-11
KR101453091B1 (en) 2014-10-27
JP5412044B2 (en) 2014-02-12
DE602008001068D1 (en) 2010-06-10

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