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    • 专利摘要:
    The present invention relates to a process for the desulfurization of a gasoline cut containing sulfur compounds, olefins and diolefins, comprising at least the following steps: a) the gasoline is fractionated so as to recover a light LCN gasoline cut and a first cut HCN heavy gasoline; b) a first step of desulfurization of the first HCN heavy gasoline cut is carried out; c) partially condensing the first desulfurization effluent from step b) so as to produce a gaseous phase consisting essentially of hydrogen and H 2 S and an HCN liquid hydrocarbon phase comprising dissolved H 2 S; d) the HCN liquid hydrocarbon phase is separated into an intermediate gasoline fraction MCN and a second heavy gasoline fraction HHCN; e) a second step of desulfurization of the second HHCN heavy gasoline cut is carried out.
    公开号:FR3056599A1
    申请号:FR1659016
    申请日:2016-09-26
    公开日:2018-03-30
    发明作者:Adrien Gomez；Garcia Clementina Lopez；Philibert Leflaive；Annick Pucci；Marie Godard-Pithon
    申请人:IFP Energies Nouvelles IFPEN；
    IPC主号:
    专利说明:

    © Publication no .: 3,056,599 (to be used only for reproduction orders)
    ©) National registration number: 16 59016 ® FRENCH REPUBLIC
    NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY
    COURBEVOIE
    ©) Int Cl 8 : C 10 G 67/02 (2017.01), C10G 45/08, 7/00, 25/00
    A1 PATENT APPLICATION
    ©) Date of filing: 09.26.16. © Applicant (s): IFP ENERGIES NOUVELLES Etablis- ©) Priority: public education - FR. ©) Inventor (s): GOMEZ ADRIEN, LOPEZ GARCIA CLEMENTINA, LEFLAIVE PHILIBERT, PUCCI (43) Date of public availability of the ANNICK and GODARD-PITHON MARIE. request: 30.03.18 Bulletin 18/13. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ©) Holder (s): IFP ENERGIES NOUVELLES Etablisse- related: public. ©) Extension request (s): @) Agent (s): IFP ENERGIES NOUVELLES.
    PROCESS FOR TREATING A GASOLINE BY SEPARATION IN THREE CUTS.
    FR 3 056 599 - A1
    The present invention relates to a process for desulfurization of a gasoline cut containing sulfur compounds, olefins and diolefins, comprising at least the following steps:
    a) the petrol is fractionated so as to recover a LCN light petrol cut and a first HCN heavy petrol cut;
    b) a first desulphurization step of the first heavy petrol HCN cut is carried out;
    c) partially condensing the first desulphurization effluent from step b) so as to produce a gas phase consisting essentially of hydrogen and H 2 S and a liquid hydrocarbon phase HCN comprising dissolved H 2 S;
    d) the liquid hydrocarbon phase HCN is separated into an intermediate gasoline cut MCN and a second heavy gasoline cut HHCN;
    e) a second desulfurization step of the second heavy gasoline cut HHCN is carried out.

    The present invention relates to a process for reducing the sulfur compound content of an olefin type gasoline, so as to produce a so-called desulphurized gasoline, while limiting the loss of octane induced by the hydrogenation of olefins and by reducing costs. of utilities and investment.
    State of the art
    The production of gasolines meeting the new environmental standards requires that their sulfur content be significantly reduced to values generally not exceeding 50 ppm (mg / kg), and preferably less than 10 ppm.
    It is moreover known that the conversion essences, and more particularly those originating from catalytic cracking, which may represent 30 to 50% of the petrol pool, have high contents of olefins and sulfur.
    The sulfur present in gasolines is for this reason attributable, to almost 90%, to gasolines resulting from the processes of catalytic cracking, which one will call hereinafter gasoline of FCC (Fluid Catalytic Cracking according to the English terminology, that l 'can be translated by catalytic cracking in a fluidized bed). FCC essences therefore constitute the preferred feed for the process of the present invention.
    Among the possible ways to produce fuels with a low sulfur content, the one that has been widely adopted consists in specifically treating the sulfur-rich gasoline bases by hydrodesulfurization processes in the presence of hydrogen and a catalyst. Traditional processes desulfurize gasolines in a non-selective manner by hydrogenating a large part of the mono-olefins, which causes a high loss in octane number and a high consumption of hydrogen. The most recent processes, such as the Prime G + process (trade mark), make it possible to desulfurize cracked gasolines rich in olefins, while limiting the hydrogenation of mono-olefins and consequently the loss of octane and the high consumption. resulting hydrogen. Such methods are for example described in patent applications EP 1077247 and EP 1174485.
    As described in patent applications EP 1077247 and EP 1800748, it is advantageous to carry out before the hydrotreatment step a step of selective hydrogenation of the feed to be treated. This first hydrogenation step essentially consists in selectively hydrogenating the diolefins, while jointly transforming by weighing down the light saturated sulfur compounds (by increasing their molecular weight). These sulfur compounds may have a boiling point below the boiling point of thiophene, such as methanethiol, ethanethiol, propanethiol and dimethylsulfide. By fractionation of the gasoline resulting from the selective hydrogenation stage, a light desulfurized gasoline cut (or LCN for Light Cracked Naphtha according to English terminology) is produced, composed mainly of mono-olefins with 5 or 6 carbon atoms without loss octane, which can be used in the petrol pool for the formulation of vehicle fuel. Under specific operating conditions, this hydrogenation selectively achieves the hydrogenation, at least partial, or even total, of the diolefins present in the feed to be treated into mono-olefinic compounds, which have a better octane number. Another effect of selective hydrogenation is to prevent the gradual deactivation of the selective hydrodesulfurization catalyst and / or to avoid a progressive blockage of the reactor due to the formation of polymerization gums on the surface of the catalysts or in the reactor. Indeed, polyunsaturated compounds are unstable and tend to form gums by polymerization.
    Patent application EP 2161076 discloses a process for the selective hydrogenation of polyunsaturated compounds, and more particularly of diolefins, making it possible to jointly weight down light sulfur compounds such as mercaptans or sulfides. This process uses a catalyst containing at least one metal from group Vlb and at least one non-noble metal from group VIII deposited on a porous support. Obtaining a gasoline with a very low sulfur content, typically at a content of less than 10 ppm by weight as required in Europe, moreover requires at least one hydrodesulfurization step which consists in converting the organo-sulfur compounds into H 2 S. However, if this step is not properly controlled it can lead to the hydrogenation of a significant part of the mono-olefins present in petrol and which then results in a sharp reduction in the octane number of petrol and overconsumption of hydrogen. Another problem encountered during the hydrodesulfurization stage is the formation of mercaptan-type compounds resulting from the addition reaction of the H 2 S formed in the hydrodesulfurization reactor on the monoolefins present in the gasoline feed. The mercaptans mentioned, of chemical formula RSH, where R is an alkyl group, are also called thiols or recombinant mercaptans and generally represent between 20% and 80% by weight of the residual sulfur in the desulfurized gasolines.
    In order to limit these drawbacks, various solutions have been described in the literature for desulfurizing cracked gasolines using a combination of hydrodesulfurization steps and elimination of recombinant mercaptans by a technique judiciously chosen to avoid the hydrogenation of mono-olefins present, in order to preserve the octane number (see for example US 7,799,210, US 6,960,291, US 6,387,249 and US 2007/114156).
    However, it appears that if these combinations implementing a final stage of elimination of the recombinant mercaptans are particularly suitable when a very low sulfur content is sought, these can prove to be very expensive when the quantity of mercaptans to be eliminated is high; indeed this requires for example high consumption of adsorbent or solvent.
    Among the solutions proposed in the literature for producing essences with reduced sulfur content, some propose the separation by distillation of the wide cut of the essence resulting from a cracking process (or FRCN for Full Range Cracked Naphtha according to English terminology). -saxonne). The objective of distillation in certain patents (for example, patents EP 1077247 and WO 02/072738) is to obtain 2 cuts: a light cut (LCN) and a heavy cut (HCN or Heavy Cracked Naphtha according to English terminology). ). FRCN gasoline can be treated upstream of distillation for example by a process allowing the selective hydrogenation of the diolefins of gasoline and / or allowing the weighting of light sulfur compounds, so that after the operation of distillation, these sulfur compounds are recovered in the heavy HCN cut. The sulfur-containing heavy cut compounds are then removed from the gasoline by various processes, for example, via catalytic hydrodesulfurization carried out with one or more reactors.
    Another solution consists in carrying out the catalytic hydrodesulfurization of the petrol feed in two hydrodesulfurization stages with an intermediate stage of separation of the H 2 S formed in the first stage. Such a solution is illustrated for example in patents EP 1174485 and US 7,785,461.
    Patents also relate to solutions combining the separation into a heavy cut and a light cut and a catalytic hydrodesulfurization carried out with two reactors with separation of the H 2 S formed in the first step. In this case, the separation of the light cut can be carried out either upstream of the two hydrodesulfurization steps as illustrated in patent EP 1354930, only the heavy cut then being desulfurized, or between the two hydrodesulfurization steps, the first step then dealing with the wide cut of gasoline resulting from a cracking process (or FRCN for Full Range Cracked Naphtha according to English terminology), the second only the heavy cut. Examples of the latter solution are illustrated in particular in US 6,913,688 and US 7,419,586.
    Other solutions use the separation by distillation of the wide cut gasoline FRCN in addition to two cuts to produce a gasoline with reduced sulfur content, or even very low sulfur contents, of the order of 10 ppm by weight. . In this type of process, the cuts obtained are treated separately or in part together for the elimination of organic sulfur from at least part of the cuts obtained, the aim being to obtain a desulfurized gasoline after mixing all or at least one part of the cuts processed.
    For example, document US 2004/188327 describes a process which makes it possible to reduce the sulfur content of an FCC gasoline by separating the FRCN gasoline by a distillation operation in three cuts: a light cut, an intermediate cut and a cut heavy. The heavy cut is desulphurized and the effluent is combined with the intermediate cut, the whole being desulphurized during a second hydrodesulphurization step. It is specified that the mercaptans contained in the light cut can be eliminated either by thioetherification upstream of the separation into three cuts, or by a caustic treatment downstream.
    US Patent 6,103,105 describes a similar process, the FRCN (Full Range Cracked Naphtha) essence also being separated into three cuts by a distillation operation. It is specified that the light cut represents between 50 and 80% of the gasoline and that the heavy cut represents from 5 to 20% of the FRCN gasoline. It is also specified that the intermediate cut and the heavy cut are hydrodesulfurized in a single reactor containing two catalytic beds. The heavy cut is treated in the 1 st catalytic bed and the intermediate cut is added between the two beds so as to carry out a co-treatment with the partially desulphurized heavy cut from the 1 st bed in the 2 nd catalytic bed. The authors indicate an almost total elimination of the sulfur as well as an almost total hydrogenation of the olefins of the heavy cut.
    The patent FR 2807061 also describes a gasoline desulfurization process comprising a selective hydrogenation step followed by separation into at least three fractions. The lightest fraction is practically free of sulfur. The heaviest fraction is treated at least once to desulfurize the unsaturated sulfur compounds from the cut. The intermediate fraction is characterized by a relatively low content of olefins and aromatics. This section undergoes in part or in whole at least one step of desulfurization and denitrogenation followed by catalytic reforming.
    US Patent 9,260,672 describes a process for producing gasoline with a low loss of octane number. According to the inventors, after saturation of the diolefins, the FRCN gasoline is separated by distillation into a light cut of end point 70 ° C., an intermediate cut (703056599
    90 ° C) and a heavy cut (90-210 ° C). The light cut mercaptans are eliminated with a caustic treatment in equipment known as CFC (or Continuous Film Contactor according to English terminology). The heavy cut, containing mainly thiophenic sulfur compounds, is desulphurized by a process of catalytic hydrodesulfurization or reactive adsorption. The intermediate cut can be sent to an isomerization or catalytic reforming unit. Optionally the intermediate cut can be co-treated with the light cut in CFC equipment to reduce the mercaptan content, or else, this cut can be co-treated with the heavy cut. This process does not provide a separate desulfurization treatment for the intermediate cut.
    Patent application US 2004/0195151 discloses a process for the selective desulphurization of gasoline FRCN. FRCN gasoline is introduced into a reactive distillation column allowing both a thioetherification treatment of the mercaptans contained in the charge and a separation into a light cut, an intermediate cut and a heavy cut. The intermediate section is withdrawn by a lateral withdrawal and is treated in a desulphurization reactor.
    The patent application US 2014/0054198 describes a method for reducing the sulfur content of a hydrocarbon stream, the method comprising bringing an FRCN gasoline into contact with a hydrogenation catalyst to hydrogenate at least part of the dienes and convert at least part of the mercaptans to thioethers. This FRCN gasoline is then fractionated into a light fraction, an intermediate fraction and a heavy fraction. The heavy fraction is desulfurized in a catalytic hydrodesulfurization process. The intermediate fraction is mixed with hydrogen and a diesel fraction to form a mixture which is brought into contact with a catalyst in a hydrodesulfurization reactor and then separated in order to obtain the desulfurized intermediate fraction and recover the diesel fraction which is recycled. in the process and optionally purged.
    An object of the present invention is to provide a process for desulfurization of an olefinic gasoline comprising a fractionation in three cuts which is capable of producing, by limiting the loss of octane number, a gasoline with a low total sulfur content, typically less than 30 ppm, or even preferably less than 10 ppm by weight and with a very low content of recombinant mercaptans.
    Summary of the invention
    The subject of the present invention is a process for treating a gasoline containing sulfur compounds, olefins and diolefins, the process comprising at least the following steps:
    a) the petrol is fractionated so as to recover a LCN light petrol cut and a first HCN heavy petrol cut;
    b) a first desulphurization step of the first heavy gasoline cut HCN is carried out in the presence of a hydrodesulfurization catalyst and hydrogen, at a temperature between 160 and 450 ° C, at a pressure between 0.5 and 8 MPa, with a liquid speed of between 0.5 and 20 h 1 and with a ratio between the flow of hydrogen expressed in normal m 3 per hour and the flow of feed to be treated expressed in m 3 per hour at the conditions standards between 50 Nm 3 / m 3 and 1000 Nm 3 / m 3 so as to produce a first desulphurization effluent;
    c) partially condensing the first desulphurization effluent from step b) so as to produce a gas phase consisting essentially of hydrogen and H 2 S and a liquid hydrocarbon phase HCN comprising dissolved H 2 S;
    d) the liquid hydrocarbon phase HCN is separated into an intermediate gasoline cut MCN and a second heavy gasoline cut HHCN;
    e) a second desulfurization step of the second heavy gasoline cut HHCN is carried out in the presence of a hydrodesulfurization catalyst and hydrogen, at a temperature between 160 and 450 ° C, at a pressure between 0.5 and 8 MPa, with a liquid speed of between 0.5 and 20 h 1 and with a ratio between the flow of hydrogen expressed in normal m 3 per hour and the flow of feed to be treated expressed in m 3 per hour at the conditions standards between 50 Nm 3 / m 3 and 1000 Nm 3 / m 3 so as to produce a second heavy gasoline cut, desulfurized HHCN, the process comprising:
    • a step c ') in which the dissolved H 2 S is separated from the HCN liquid hydrocarbon phase resulting from step c) to produce a HCN liquid hydrocarbon phase with a low content of dissolved H 2 S and said HCN liquid hydrocarbon phase with a low content of dissolved H 2 S being treated in step d), or • a step d ') in which the dissolved H 2 S is separated from the intermediate gasoline cut MCN resulting from step d) to produce a MCN intermediate gasoline cut with low dissolved H 2 S content.
    The method according to the invention responds to the problem of desulfurizing an olefin gasoline while limiting the hydrogenation of olefins and reducing the content of recombinant mercaptans in the desulfurized effluents, thanks to the combination of the steps mentioned above. Thus step a) is carried out so as to separate a light gasoline cut with a high octane number and a reduced content of sulfur compounds without involving a catalytic hydrodesulfurization reaction which would cause a hydrogenation of part of the olefins. Step b) performs a partial desulfurization of the HCN gasoline cut (complementary to the LCN cut) during which recombinant mercaptans are formed resulting from the reaction of the olefins with the H 2 S formed. Step d) contributes to the efficiency of the process thanks to the separation of the partially desulphurized HCN gasoline cut, judiciously operated, into an MCN intermediate gasoline cut with low sulfur content and in a second heavy gasoline HHCN cut containing sulfur compounds. organic including recombinant mercaptans which have higher boiling temperatures than those of the olefins from which they are derived. The desulfurization step e) of the second heavy gasoline cut HHCN, which can be carried out under more severe conditions than that of step b) insofar as the fractions richest in olefins have been separated beforehand, makes it possible to perform a deep treatment to provide an effluent with a low sulfur content.
    The process according to the invention also comprises a step of separation of the H 2 S which is produced during step b) of desulphurization and part of which is found in dissolved form in the liquid hydrocarbon phase resulting from the step vs). This separation step aims to ultimately provide a heavy HHCN gasoline cut with a low H 2 S content which can then be treated in the desulfurization step e). The separation of H 2 S can be carried out directly on the HCN liquid hydrocarbon phase resulting from step c) (step c '). Alternatively, the process according to the invention comprises a step for separating the H 2 S (step d) which is carried out after step d) for separating the liquid hydrocarbon phase HCN into an intermediate gasoline cut MCN (and which also contains H 2 S) and a second heavy gasoline cut HHCN heavier than the cut MCN. This step d ') is therefore carried out on the intermediate gasoline cut MCN which contains the majority of the H 2 S formed. For example, step d ') consists in sending the MCN intermediate cut and a gas allowing the H 2 S dissolved in the MCN gasoline cut to be stripped through a stripping column. Step dj can also use a stabilization column making it possible to separate, at the top of the column, a C4 hydrocarbon fraction containing H 2 S and a stabilized MCN fraction at the bottom of the column.
    Step a) is carried out in such a way that the final boiling point of the light gasoline cut provides a LCN light gasoline cut with a low sulfur content (total sulfur content typically less than 30 ppm by weight and preferably less than 10 ppm weight) without requiring a subsequent hydrodesulfurization step.
    Preferably, the intermediate gasoline cut MCN has a temperature difference ΔΤ between the points at 5% and at 95% of distilled mass which is less than 75 ° C. (determined according to the CSD method described in the document Oil Gas Sci. Technol. Vol. 54 (1999), No. 4, pp. 431-438). Preferably, the temperature difference ΔΤ between the 5% and 95% points of distilled mass is between 20 and 65 ° C. The intermediate gasoline MCN can contain hydrocarbons having from 5 to 8 carbon atoms and mainly hydrocarbons with 6 carbon atoms.
    According to the invention, steps cj or dj are carried out by stripping with a gas. For example, the stripping gas is hydrogen, nitrogen or water vapor.
    Alternatively, steps cj or dj are performed by an absorption method. According to another embodiment of the method, steps cj or dj are carried out in a stabilization column configured to separate a hydrocarbon phase C4 ′ containing H 2 S and a liquid hydrocarbon phase HCN (stabilized) with low H content 2 S dissolved, said liquid hydrocarbon phase HCN with a low content of dissolved H 2 S being treated in step
    d).
    According to another embodiment, steps cj and d) are carried out concomitantly in a fractionation column configured to separate:
    • a gas phase containing essentially H 2 S which is drawn off at the top of the column;
    • the intermediate gasoline cup MCN which is withdrawn with the reflux balloon or laterally below the head of the column;
    • the second HHCN heavy gasoline cut purified in dissolved H 2 S which is drawn off at the bottom of the column.
    In this case and preferably the intermediate gasoline cut MCN resulting from the fractionation is sent to a stabilization column, possibly in that which processes the desulfurized HHCN cut produced in step e).
    According to the invention, the intermediate gasoline cut MCN is optionally treated in a step f) of hydrodesulfurization. Step f) is carried out in the presence of a hydrodesulfurization catalyst and hydrogen, at a temperature between 160 and 450 ° C, at a pressure between 0.5 and 8 MPa, with a liquid speed between 0.5 and 20 h 1 and with a ratio between the hydrogen flow rate expressed in normal m 3 per hour and the feed flow rate to be treated expressed in m 3 per hour at standard conditions between 50 Nm 3 / m 3 and 1000 Nm 3 / m 3 .
    Preferably, the desulphurized intermediate MCN gasoline cut resulting from step f) is sent to a stabilization column.
    In an alternative embodiment, the MCN intermediate gasoline cut is treated in a liquid / liquid extraction or extractive distillation or adsorption process so as to produce an MCN intermediate gasoline cut with a low content of thiophenic sulfur compounds.
    Advantageously, before step a), the gasoline is treated in the presence of hydrogen and of a selective hydrogenation catalyst so as to at least partially hydrogenate the diolefins and carry out a weighting reaction of a portion sulfur compounds, step a) being carried out at a temperature between 100 and 190 ° C, at a pressure between 1 and 4 MPa, with a space velocity between 1 and 20 h ' 1 and with a ratio between the hydrogen flow expressed in normal m3 per hour and the charge flow to be treated expressed in m 3 per hour at standard conditions between 2 Nm 3 / m 3 and 100 Nm 3 / m 3 .
    The hydrodesulfurization catalysts of steps b) and e) comprise at least one element from group VIII, at least one element from group Vlb and a support.
    The method according to the invention is used to treat a gasoline cut from a catalytic or thermal cracking unit such as for example a deferred coking unit (or "Delayed Coker" according to English terminology) or visbreaking.
    Detailed description of the invention
    The other characteristics and advantages of the invention will appear on reading the description which follows, given by way of illustration only and without limitation, and with reference to the following figures:
    • Figure 1 is a first block diagram of the method according to the invention;
    • Figure 2 is a block diagram of a variant of the method according to the invention;
    • Figure 3 is a block diagram of another variant of the method according to the invention.
    Generally, similar elements are denoted by identical references in the figures.
    - Description of the load:
    The process according to the invention makes it possible to treat any type of cut olefinic gasoline containing sulfur whose range of boiling points typically extends from about the boiling points of hydrocarbons with 2 or 3 carbon atoms (C2 or C3 ) up to about 250 ° C, preferably from about the boiling bridges of hydrocarbons with 2 or 3 carbon atoms (C2 or C3) up to about 220 ° C, more preferably from about the dots boiling of hydrocarbons with 4 carbon atoms up to about 220 ° C. The method according to the invention can also work charges having end points lower than those mentioned above, such as for example a C5-200 ° C or C5-160 ° C cut.
    The method according to the invention makes it possible to preferably treat a gasoline cut obtained from a catalytic or thermal cracking unit such as for example a deferred coking unit (or "Delayed Coker" according to the English terminology) or visbreaking. A charge from the mixture of cuts from these different origins is also possible. In particular, the gasoline cut of the process according to the invention comes from a catalytic cracking unit whose charge is pretreated or operating so as to increase or even maximize the yield of propylene. In the latter case, the operating mode of the catalytic cracking unit is typically characterized by severe operating conditions (high temperature and with a high catalyst to charge ratio), by the use of a catalyst comprising a selectivity zeolite. of shape (for example of crystalline structure MFI), with a possible recycling of a part of the gasoline cut produced or of an oligomerate of the C4 cut in the catalytic cracking unit, this flow of recycle being able to be treated either by at the same time as the feed (coprocessing according to English terminology) is in a dedicated reactor in order to dissociate the cracking conditions of the heavy feed and those of the recycled stream (process known as two risers).
    The sulfur content of gasoline cuts produced by catalytic cracking (FCC) or non-catalytic depends on the sulfur content of the charge treated, the presence or not of a pretreatment of the charge, as well as the end point of the cut. Generally, the sulfur contents of an entire gasoline cut, in particular those coming from the FCC, are greater than 100 ppm by weight and most of the time greater than 500 ppm by weight. For gasolines having end points greater than 200 ° C., the sulfur contents are often greater than 1000 ppm by weight, they can even, in certain cases, reach values of the order of 4000 to 5000 ppm by weight.
    For example, gasolines from catalytic cracking units (FCC) contain, on average, between 0.5% and 5% by weight of diolefins, between 20% and 50% by weight of olefins, between 10 ppm and 0.5% weight of sulfur of which generally less than 300 ppm of mercaptans. Mercaptans are generally concentrated in the light fractions of petrol and more specifically in the fraction whose boiling temperature is below 120 ° C.
    The sulfur species contained in the feeds treated by the process of the invention can be mercaptans or heterocyclic compounds, such as for example thiophenes or alkyl-thiophenes, or heavier compounds, such as for example benzothiophene. These heterocyclic compounds, unlike mercaptans, cannot be removed by the extractive processes. These sulfur-containing compounds are therefore eliminated by hydrotreatment, which leads to their transformation into hydrocarbons and into H 2 S.
    With reference to FIG. 1 which represents a particular mode of the invention, an olefinic gasoline feed, for example a catalytic cracking gasoline described above, is treated in an optional step which performs the selective hydrogenation of the diolefins and the conversion (weighting ) of a part of the mercaptan compounds (RSH) present in the thioether charge, by reaction with mono-olefins. Typically the mercaptans which can react during the optional selective hydrogenation stage are the following (non-exhaustive list): methyl mercaptan, ethyl mercaptan, n-propyl mercaptan, isopropyl mercaptan, iso-butylmercaptan, tert-butyl mercaptan, n-butylmercaptan, secbutyl mercaptan, iso-amyl mercaptan, n-amyl mercaptan, a-methyl-butyl mercaptan, Ι'α-ethylpropyl mercaptan, n-hexyl mercaptan, 2-mercapto-hexane. To this end, the FRCN petrol charge is sent via line 1 to a selective hydrogenation catalytic reactor 2 containing at least one fixed or movable bed of catalyst for the selective hydrogenation of diolefins and the weighting of mercaptans. The reaction for the selective hydrogenation of diolefins and the weighting down of mercaptans is preferably carried out on a sulfur catalyst comprising at least one element from group VIII (groups 8, 9 and 10 of the new periodic classification Handbook of Chemistry and Physics, 76th edition , 1995-1996) and possibly at least one element from the group Vlb (group 6 of the new periodic classification Handbook of Chemistry and Physics, 76th edition, 1995-1996) and a support. The element of group VIII is preferably chosen from nickel and cobalt and in particular nickel. The element of the group Vlb, when it is present, is preferably chosen from molybdenum and tungsten and very preferably molybdenum.
    The catalyst support is preferably chosen from alumina, nickel aluminate, silica, silicon carbide, or a mixture of these oxides. Alumina is preferably used and even more preferably high purity alumina. According to a preferred embodiment, the selective hydrogenation catalyst contains nickel with a content by weight of nickel oxide (in NiO form) of between 4 and 12%, and molybdenum with a content by weight of molybdenum oxide. (in Mo03 form) of between 6% and 18% and a nickel / molybdenum molar ratio of between 1 and 2.5, the metals being deposited on a support consisting of alumina and the sulfurization rate of the metals constituting the catalyst being greater than 80%.
    During the optional selective hydrogenation step, the gasoline to be treated is typically brought into contact with the catalyst at a temperature between 50 ° C and 250 ° C, and preferably between 80 ° C and 220 ° C, and even more preferably between 90 ° C. and 200 ° C., with a liquid space speed (LHSV) of between 0.5 h 1 and 20 h 1 , the unit of the liquid space speed being the liter of charge per liter. of catalyst per hour (l / lh). The pressure is between 0.4 MPa and 5 MPa, preferably between 0.6 and 4 MPa and even more preferably between 1 and 2 MPa. The optional selective hydrogenation stage is typically carried out with an H 2 / HC ratio of between 2 and 100 Nm 3 of hydrogen per m3 of charge, preferably between 3 and 30 Nm 3 of hydrogen per m 3 of charge .
    The entire charge is generally injected at the inlet of the reactor. However, it may be advantageous in certain cases to inject a fraction or all of the charge between two consecutive catalytic beds placed in the reactor. This embodiment makes it possible in particular to continue operating the reactor if the inlet of the reactor is blocked by deposits of polymers, particles, or gums present in the feed.
    As shown in Figure 1, the olefinic gasoline charge is sent via line 1 to the selective hydrogenation reactor 2. An effluent with low contents of diolefins and mercaptans is withdrawn from reactor 2 via line 3 and is sent, according to l 'step a), in a fractionation column 4 (or splitter according to English terminology) configured to separate gasoline into two cuts: a light gasoline LCN 5 cut (or light gasoline) and a (first) heavy gasoline cut HCN 6 which is made up of the complementary heavy fraction of LCN light petrol. The final boiling point of the light cut is chosen so as to provide a LCN light gasoline cut with a low sulfur content (total sulfur content typically less than 30 ppm by weight and preferably less than 10 ppm by weight) without requiring a step. subsequent hydrodesulfurization. Thus preferably the LCN light petrol cut is a C5 hydrocarbon cut (ie containing hydrocarbons having 5 and less than 5 carbon atoms per molecule). The first heavy gasoline HCN cut which is preferably a C6 + cut (ie containing hydrocarbons which may have 6 and more than 6 carbon atoms per molecule), is treated in a step b) of selective hydrodesulfurization (selective HDS). The purpose of this step b) is to use, using a catalyst described below and hydrogen, to convert part of the sulfur compounds of the heavy gasoline cut HCN into H 2 S and hydrocarbons.
    The first heavy gasoline cut HCN 6 is thus brought into contact with hydrogen supplied by line 7 and a selective HDS catalyst in at least one hydrodesulfurization unit 8 which comprises at least one fixed or mobile bed reactor of catalyst. The hydrodesulfurization reaction is generally carried out at a temperature between 160 ° C and 450 ° C, under a pressure between 0.5 and 8 MPa. The liquid space velocity is generally between 0.5 and 20 h 1 (expressed in volume of liquid per volume of catalyst and per hour), preferably between 1 and 8 h -1. The H 2 / first cut heavy HCN gasoline ratio is adjusted as a function of the desired hydrodesulfurization rates in the range between 50 and 1000 normal m 3 per m 3 under standard conditions. Preferably, the mixture of the first heavy gasoline cut HCN with the hydrogen brought into contact with the catalyst in step b) is entirely in the vapor phase. Preferably the temperature is between 200 ° C and 400 ° C, and very preferably between 200 ° C and 350 ° C. Preferably the pressure is between 1 and 3 MPa.
    The selective HDS catalyst used in sulfurized form comprises at least one element from group VIII (groups 8, 9 and 10 of the new periodic classification Handbook of Chemistry and Physics, 76th edition, 1995-1996), at least one element of group Vlb (group 6 of the new periodic classification Handbook of Chemistry and Physics, 76th edition, 1995-1996) and a support. The element of group VIII is preferably chosen from nickel and cobalt and in particular cobalt. The element of group Vlb is preferably chosen from molybdenum and tungsten and very preferably molybdenum. The catalyst may for example be a catalyst as described in documents FR 2840315, FR 2840316, FR 2904242 or FR 3023184. The catalyst support is preferably chosen from alumina, nickel aluminate, silica, carbide of silicon, or a mixture of these oxides. Alumina is preferably used.
    it should be noted that the hydrogen supplied by line 7 can be fresh hydrogen (make-up according to English terminology), or hydrogen called recycle coming from a stage of the process, in particular from l 'step b). Preferably the hydrogen of line 7 is fresh hydrogen. The first desulphurization effluent from step b) evacuated via line 9 then is cooled and partially condensed so as to produce in the separator 10 (step c)) two phases: a gaseous phase 11 rich in hydrogen and containing a portion H 2 S produced by the desulfurization in step b) and a liquid hydrocarbon phase HCN containing dissolved H 2 S, unconverted sulfur compounds and recombinant mercaptans.
    As shown in FIG. 1, the liquid hydrocarbon phase HCN 12 comprising dissolved H 2 S withdrawn from the separator 10 is sent to a step for separating the dissolved H 2 S (step c ′)). In the embodiment of FIG. 1, this step cj is implemented in a column 13 for stripping H 2 S. The liquid hydrocarbon phase HCN comprising dissolved H 2 S 12 is brought into contact with a gas such as hydrogen supplied by line 15 in the stripping column of H 2 S 13 from which a gas stream 14 containing the stripping gas and H 2 S is drawn off at the head and, at the bottom column, the liquid hydrocarbon phase HCN with a low content of dissolved H 2 S 16. It should be noted that when the stripping gas is hydrogen, the gas stream 14 can advantageously be treated to separate the hydrogen from the H 2 S so as to produce a stream of purified hydrogen which can be recycled in a hydrodesulfurization unit, for example in the first hydrodesulfurization unit 8. For the step of removing H 2 S, it is also possible to use, in place of a stripping unit, an absorption device using for example amines. The liquid hydrocarbon phase HCN with a low content of dissolved H 2 S 16 which is preferably a C6 + cut (ie containing hydrocarbons which may preferably have 6 and more than 6 carbon atoms per molecule) is, depending on the step d) of the process, sent to a fractionation column 17 configured to separate at the head an intermediate gasoline cut MCN which is drawn off through line 18 and at the bottom a second heavy gasoline cut HHCN drawn off through line 19. Since step b) is operated so as to ensure a high conversion of the light thiophenic sulfur compounds (mainly thiophene and methyl thiophenes), the intermediate gasoline cut MCN obtained after the fractionation of step d) contains only low contents in non thiophenic sulfur compounds converted. The intermediate gasoline cut MCN is, thanks to step d) of fractionation, also freed from most of the recombinant mercaptans contained in the effluent which are formed during step b) of hydrodesulfurization. In fact, in general, recombinant mercaptans have higher boiling temperatures than those of the olefins from which they come. For example 2-methyl2-pentene (boiling point in pure body under normal conditions: 67 ° C) can form a recombination mercaptan with 5 carbon atoms like 2-methyl-2penthanethiol (boiling point in body pure under normal conditions: 125 ° C). This property is thus used in stage d) to produce an intermediate gasoline cut MCN with low content of sulfur and recombinant mercaptans insofar as said recombinant mercaptans whose boiling temperature is higher than that of the gasoline cut MCN middlemen are trained in the second heavy gasoline HHCN cut.
    To obtain the intermediate gasoline cut MCN, the operating conditions of the fractionation column are adjusted so as to obtain a cut of hydrocarbons whose temperature difference (ΔΤ) between the temperatures corresponding to 5% and 95% of the distilled mass which is less than or equal to 75 ° C, preferably which is between 20 ° C and 65 ° C. The temperature corresponding to 5% of the distilled mass of the intermediate gasoline cut MCN is preferably between 50 ° C and 80 ° C and the temperature corresponding to 95% of the distilled mass of the intermediate gasoline cut MCN is preferably between 88 ° C and 125 ° C. For example the intermediate gasoline cut MCN has a temperature corresponding to 5% of the distilled mass which is equal to 65 ° C ± 2 ° C, or equal to 60 ° C ± 2 ° C or equal to 55 ° C ± 2 ° C. Preferably the intermediate gasoline cut MCN has a temperature corresponding to 95% of the distilled mass which is equal to 120 ° C ± 2 ° C, or even equal to 115 ° C ± 2 ° C. The method used to determine the temperatures corresponding to 5% and 95% of the distilled mass is described in the document Oil Gas Sci. Technol. Flight. 54 (1999), No. 4, pp. 431-438 under the name "CSD method" (abbreviation of Conventional Simulated Distillation according to English terminology) and which can be translated by Conventional Simulated Distillation.
    In a preferred embodiment, the intermediate gasoline cut MCN essentially contains hydrocarbons having from 6 to 7 carbon atoms and mainly hydrocarbons with 6 carbon atoms.
    Typically the content of total organic sulfur in the intermediate gasoline cut MCN recovered at the head of the fractionation column of step d) is less than 30 ppm by weight, preferably less than 15 ppm by weight and more preferably less than 10 ppm total sulfur weight.
    In accordance with step e) of the process, the second heavy gasoline HHCN cut is treated by hydrodesulfurization. Said gasoline section, drawn off from the bottom of the column 17 by line 19, is brought into contact with hydrogen supplied by line 23 in at least one hydrodesulfurization unit 24. This step e) of selective hydrodesulfurization thus allows to convert the sulfur-containing compounds of the HHCN heavy petrol cut (including the major part of the recombinant mercaptans formed in the hydrodesulfurization stage b)) into H 2 S and hydrocarbons. Step e) of selective hydrodesulfurization is carried out in the presence of hydrogen supplied by line 23 and of a selective hydrodesulfurization catalyst which comprises at least one element from group VIII (groups 8, 9 and 10 of the new classification Periodical Handbook of Chemistry and Physics, 76th edition, 1995-1996), at least one element from the group Vlb (group 6 of the new periodic classification Handbook of Chemistry and Physics, 76th edition, 1995-1996) and a support. The element of group VIII is preferably chosen from nickel and cobalt and in particular cobalt. The element of group Vlb is preferably chosen from molybdenum and tungsten and very preferably molybdenum. The catalyst may for example be a catalyst as described in documents FR 2840315, FR 2840316, FR 2904242 or FR 3023184. The hydrodesulfurization reaction is generally carried out at a temperature between 200 ° C and 450 ° C, under pressure between 05 and 8 MPa. The liquid space velocity is generally between 0.5 and 20 h 1 (expressed in volume of liquid per volume of catalyst and per hour), preferably between 1 and 8 h 1 . The H 2 / HHCN cut ratio which is adjusted as a function of the desired hydrodesulfurization rates is in the range between 50 and 1000 normal m 3 per m 3 at standard conditions.
    Preferably the temperature is between 200 ° C and 400 ° C, and very preferably between 200 ° C and 350 ° C. Preferably the pressure is between 0.5 and 3 MPa.
    At the end of step e), a second cut of desulfurized HHCN heavy gasoline which typically has an organic sulfur content of less than 30 ppm by weight, is preferably withdrawn from the selective hydrodesulfurization unit, via line 25. at 15 ppm by weight and even more preferably less than 10 ppm by weight.
    Optionally, the intermediate gasoline cut MCN 18 is also treated in a hydrodesulfurization step. To this end, it is brought into contact with hydrogen supplied by line 20 and a selective hydrodesulfurization catalyst in at least one hydrodesulfurization unit 21 which comprises at least one reactor with a fixed or movable bed of catalyst (step optional f)). The hydrodesulfurization reaction is generally carried out at a temperature between 160 ° C and 450 ° C, be a pressure between 0.5 and 8 MPa. The liquid space velocity is generally between 0.5 and 20 h 1 (expressed in volume of liquid per volume of catalyst and per hour), preferably between 1 and 8 h 1 . The H 2 / MCN intermediate gasoline cut ratio is adjusted as a function of the desired hydrodesulfurization rates in the range between 50 and 1000 normal m 3 per m 3 under standard conditions. Preferably, the mixture of the intermediate gasoline cut MCN with the hydrogen brought into contact with the catalyst in the optional step f) is entirely in the vapor phase. Preferably the temperature is between 200 ° C and 400 ° C, and very preferably between 200 ° C and 3> 0 ° C. Preferably the pressure is between 1 and 3 MPa. The catalyst used in step f) can be a catalyst of the type used for steps b) and e). It should be noted that the hydrogen supplied by line 20 can be fresh hydrogen (make-up according to English terminology), or hydrogen called recycle coming from a stage of the process.
    The process may include a step for stabilizing the effluents from steps e) and
    f) hydrodesulfurization of the HHCN and MCN gasoline cuts respectively in order to separate the fraction of light hydrocarbons C4- in mixture with the H 2 S formed during the hydrodesulfurization steps and hydrogen. According to the embodiment of Figure 1, the intermediate MCN desulfurized gasoline cuts from line 22 and the second heavy gasoline HHCN desulfurized cut from line 25 are sent as a mixture through line 26 into a stabilization column 27 from which it is drawn off. at the head of the column by line 28, the C4 hydrocarbon fraction in mixture with H 2 S and at the bottom of the column, a mixture of desulphurized MCN and HHCN gasoline, stabilized, by line 29.
    Alternatively, the residual thiophenic sulfur compounds contained in the intermediate gasoline cut MCN can be extracted with an appropriate polar solvent in a liquid-liquid extraction or extractive distillation process or by adsorption on appropriate adsorbents (silicas, aluminas, zeolites as described in document FR 2 889 539 A1).
    LCN light gasoline cuts, and the mixture of desulphurized MCN and HHCN gasoline, produced by the process according to the invention, are advantageously used as bases for the formulation of a gasoline fuel.
    According to another embodiment not shown, the method does not implement the step cj of separation of the H 2 S dissolved in the liquid hydrocarbon phase HCN, but employs a step dj downstream of the step d) of separation of the MCN intermediate petrol cuts and second HHCN heavy petrol cut. Step dj consists in removing the H 2 S present in the intermediate gasoline cut MCN obtained in step d). For example, step dj is carried out by stripping with a gas or by using a stabilization column which separates at the head of the column a stream containing a C4 hydrocarbon cut and of H 2 S and at the bottom a stabilized MCN intermediate petrol cut .
    Figure 2 is a diagram of the method according to another embodiment. This embodiment differs from that of FIG. 1 by the method of implementing steps cj and d). With reference to FIG. 2, the liquid hydrocarbon phase HCN comprising dissolved H 2 S, resulting from step c) is sent by line 12 in a fractionation column 17 ′ designed and operated so as to carry out the steps cj and d) concomitantly, in order to separate:
    • a gaseous phase essentially containing H 2 S which is drawn off at the head of column 17 'via line 14;
    • the intermediate petrol cup MCN 18 which is withdrawn laterally from a few trays below the head of the column;
    • the second heavy fuel cut HHCN 19 which is drawn off at the bottom of the column. Column 17 ′ can optionally be supplied by line 15 with a stripping gas such as hydrogen in order to improve the separation of H 2 S.
    The intermediate gasoline cut MCN 18 can then be treated in a hydrodesulfurization reactor as already indicated in Figure 1 (optional step f) and then stabilized alone or in mixture with the second heavy gasoline cut HHCN desulfurized from step e) .
    Figure 3 shows an alternative embodiment of the method according to the invention in which steps cj and d) are carried out concomitantly in a 17 ”fractionation column configured to separate:
    • at the head of the column a gaseous phase containing hydrocarbons of the intermediate gasoline cut MCN and of H 2 S (line 18 ');
    • the second heavy gasoline HHCN cut (with a low content of dissolved H 2 S) which is drawn off at the bottom of the column by line 19;
    The gas phase 18 ′ is then cooled in order to condense the intermediate gasoline cut MCN. To this end, said gaseous phase 18 ′ is cooled by means of the cold unit 30 and the cooled effluent is then sent to a separator flask 31 making it possible to recover a gas flow 32 containing essentially hydrogen and H 2 S with possibly light hydrocarbons and at the bottom of the tank a liquid hydrocarbon phase 18 corresponding to the intermediate gasoline cut MCN. As shown in Figure 3, part of the MCN 18 intermediate gasoline is recycled to the 17 ”fractionation column as reflux liquid. The other part of the intermediate gasoline MCN can be hydrodesulfurized (according to the optional step f) or simply stabilized. The stabilization step of the intermediate gasoline cut MCN (desulfurized or not) can be carried out in mixture with the second cut heavy gasoline cut HHCN desulfurized in column 27.
    Example 1: Pretreatment of the FCC petrol charge by selective hydrogenation
    Table 1 gives the characteristics of an FRCN gasoline treated by the process according to Figure 1 of the present invention.
    The FCC gasoline (line 1) is treated in the selective hydrogenation reactor 2 in the presence of a catalyst A (optional step). Catalyst A is a NiMo type catalyst on gamma alumina. The metal contents are respectively 7% by weight NiO and 11% by weight Mo0 3 relative to the total weight of the catalyst, ie a molar ratio Ni / Mo of 1.2. The specific surface of the catalyst is 230 m 2 / g. Prior to its use, catalyst A is sulfurized at atmospheric pressure in a sulfurization bench under H 2 S / H 2 mixture consisting of 15% by volume of H 2 S at 1 L / gh of catalyst and at 400 ° C for two hours . This protocol makes it possible to obtain a sulfurization rate greater than 80%.
    The gasoline FRCN (line 1) is brought into contact with hydrogen in a reactor which contains catalyst A. This stage of the process carries out the selective hydrogenation of the diolefins and the conversion (weighting down) of a part of the mercaptan compounds (RSH) present in the load. The diolefin content is directly proportional to the value of the MAV (Maleic Anhydride Index or Maleic Anhydrid Value according to English terminology). Diolefins are undesirable compounds because they are precursors of gums in gasolines.
    The operating conditions used in the selective hydrogenation reactor are: Temperature: 140 ° C, Total pressure: 2.5 MPa, volume ratio H 2 added / petrol charge FRCN: 5 normal liters of hydrogen per liter of petrol (flight / flight), hourly volume speed (WH): 3 h ' 1 .
    Line 1FRCN Line 3Effluenthydrogenationselective Organic sulfur content (ppm weight S) 978 980 MY V (mg / g) 12 0.6 Olefin content (% weight) 31% 31% Simulated distillation 5% distilled mass (° C) 23 23 50% distilled mass (° C) 95 95 95% distilled mass (° C) 198 198 Table 1: Characteristics of the c large FRCN (1) and 'selective hydrogenation effluent (3).
    The effluent from the selective hydrogenation stage (3) with a low content of conjugated diolefins (MV = 0.6 mg / g) and low content of light sulfur compounds (weighed down in the selective hydrogenation stage) is sent to a fractionation column (4) according to step a) of the present invention in order to separate a light LCN gasoline at the top (5) and at the bottom of the column a first HCN heavy gasoline cut (6). The characteristics of the light LCN petrol and of the first heavy petrol cut HCN are indicated in Table 2. As indicated in Table 2, the LCN petrol obtained (line 5) has a low sulfur content (15 ppm). The first HCN heavy petrol cut, which corresponds to approximately 68% by mass of FRCN petrol, has a very high sulfur content (1430 ppm) and requires additional treatment before being incorporated into the petrol pool.
    Line 5LCN Line 6HCN Mass percentage of the cut % 32 68 Organic sulfur content (ppm weight S) 15 1430 Olefin content (% weight) 48% 23%
    Table 2: Characteristics of cuts: LCN light petrol and first HCN heavy petrol cut
    Example 2 (Comparative): Hydrodesulfurization of the first heavy fuel oil cut HCN
    This example refers to the prior art (patent EP 1174485). The first heavy gasoline HCN cut obtained in Example 1 is mixed with hydrogen and treated in a selective hydrodesulfurization unit 8 which corresponds to a first hydrodesulfurization step. The first hydrodesulfurization step is carried out in the presence of a CoMo catalyst supported on alumina (HR806 sold by the company Axens). The pressure is 2 MPa, the space velocity of the liquid (expressed in volume of liquid per volume of catalyst and per hour) is 4 h 1 , the ratio H2 / cut HCN is 360 normal m 3 per m 3 under the conditions standards. The reactor effluent is then condensed 10 and stripped 13 with hydrogen so as to extract the dissolved H2S. The content of organic sulfur and olefins in the HCN liquid hydrocarbon phase with low H 2 S content (line 16) are shown in Table 3.
    The HCN liquid hydrocarbon phase with a low H 2 S content (16) is then treated in a second selective hydrodesulfurization unit 24 which corresponds to a second hydrodesulfurization step. This step is carried out in the presence of a CoMo catalyst supported on alumina (HR806 sold by the company Axens). The pressure is 2 MPa, the space velocity of the liquid (expressed in volume of liquid per volume of catalyst and per hour) is 4 h 1 , the H 2 / liquid hydrocarbon ratio is 360 normal m 3 per m 3 in the standard conditions. The effluent from reactor 24 can be sent, for example, to a stabilization column, in order to recover at the top of the column hydrogen and H2S, possibly with light hydrocarbons and at the bottom of the column an HCN hydrocarbon cut. from a second hydrodesulfurization step. The characteristics of the HCN obtained after the second hydrodesulfurization step and stabilized, are illustrated in Table 3.
    Heavy gasoline HCNhydrodesulfurizedFirst stage Heavy gasoline HCNhydrodesulfurizedSecond step Organic sulfur content (ppm S) 150 15 Olefin content (% weight) - 15
    Table 3: Characteristics of HCN heavy petrol after the first and second hydrodesulfurization stage
    Loss of olefins (absolute) Loss of olefins (% weight) 7.8%
    Table 4: Loss of olefins between the first cut heavy HCN gasoline and the gasoline obtained after the second hydrodesulfurization stage
    The method according to example 2 makes it possible to obtain an HCN gasoline with a low sulfur content (15 ppm by weight). The loss of olefins between the first heavy petrol HCN cut and the stabilized petrol obtained after the second hydrodesulfurization stage is 7.8% by mass (in absolute)
    EXAMPLE 3 Hydrodesulfurization of the First Heavy Gasoline HCN Cut (According to the Present Invention)
    This example refers to the present invention. The first heavy gasoline HCN cut obtained in Example 1 is mixed with hydrogen and treated in a selective hydrodesulfurization unit (8) which corresponds to step b) of the present invention. The hydrodesulfurization step b) is carried out in the presence of a CoMo catalyst supported on alumina (HR806 sold by the company Axens). The pressure is 2 MPa, the space velocity of the liquid (expressed in volume of liquid per volume of catalyst and per hour) is 4 h 1 , the H 2 / HCN cut ratio is 360 normal m 3 per m 3 in the standard conditions. The effluent from reactor 8 is then condensed (according to step c) of the invention) in order to remove the hydrogen and hydrogen sulfide in the vapor phase. The HCN liquid hydrocarbon phase comprising dissolved H 2 S is sent to a stripping step (step c ′ according to the invention) illustrated by the stripping column 13 of FIG. 1. At the top of column 13 is withdrawn a gas flow 14 containing the stripping gas and H 2 S and, at the bottom of the column, a liquid hydrocarbon phase HCN with a low content of dissolved H 2 S 16.
    The HCN liquid hydrocarbon phase with a low content of dissolved H 2 S (and which was at least partially hydrodesulfurized in step b) is sent to a fractionation column 17 (step d according to the present invention). The column is configured to separate at the head an intermediate gasoline cut MCN which is drawn off through line 18 and at the bottom a second heavy gasoline cut HHCN drawn off through line 19. The operation of the fractionation column is adjusted so as to obtain a cut MCN whose temperature at 95% of the distilled mass of the intermediate gasoline cut MCN is 102 ° C ± 5 ° C (temperatures measured according to method C © described in the document Oil Gas Sci. Technol. Vol. 54 (1999) , No. 4, pp. 431-438). The operation of the fractionation column is also adjusted so as to obtain at the bottom of the column, a second heavy gasoline cut HHCN whose temperature at 5% of distilled mass is 102 ° C ± 5 ° C (temperatures measured according to the method CSD described in the document Oil Gas Sci. Technol. Vol. 54 (1999), No. 4, pp. 431-438).
    The second HHCN heavy gasoline cut 19 is mixed with hydrogen and treated in a selective hydrodesulfurization unit 24 according to step e) of the present invention. The hydrodesulfurization step e) is carried out in the presence of a CoMo catalyst supported on alumina (HR806 sold by the company Axens). The pressure is 2 MPa, the space velocity of the liquid (expressed in volume of liquid per volume of catalyst and per hour) is 4 h 1 , the H 2 / HCN cut ratio is 360 normal m 3 per m 3 in the standard conditions. The second desulfurized HHCN heavy gasoline cut is stabilized after step e).
    The characteristics of the intermediate gasoline cut MCN 18, of the second heavy gasoline cut HHCN 19 and of the second heavy gasoline cut HHCN desulfurized (after stabilization) are indicated in Table 5.
    HCN liquid hydrocarbon phase with low H 2 S content Line 16 Chopped offessenceintermediateMCN Secondpetrol cutterheavy HHCN Secondpetrol cutterheavy HHCNdesulfurizedand stabilized Contentorganic sulfur (ppm weight S) 72 15 107 15 Contentolefins (% weight) 17% 28% 10% 9% Percentagemass of thecut (bycompared to theFRCN) (% weight) 68% 26% 42% 42% Table 5: Characteristics of e the HCN liquid hydrocarbon phase with a low H2S content,
    of the intermediate gasoline cut MCN, of the second heavy gasoline cut HHCN and of the second heavy gasoline cut HHCN desulfurized and stabilized according to the present invention
    Loss of olefins (absolute) Loss of olefins (% weight) 6.6%
    Table 6: Loss of olefins between the first heavy fuel cut HCN and the mixture of gasoline cuts intermediate fuel MCN and second cut heavy fuel HHCN desulfurized and stabilized
    The process according to the invention thus makes it possible to obtain, after stabilization, an intermediate MCN gasoline cut with a low organic sulfur content (15 ppm) and, after stabilization, a second heavy gasoline desulfurized HHCN cut with a low organic sulfur content (15 ppm). ). These gasolines can, with the light LCN gasoline obtained in Example 1, be used in the gasoline pool for the formulation of fuel for vehicles.
    Very advantageously, the mixture of the first heavy gasoline cut HCN and the mixture of gasolines intermediate gasoline cut MCN and second heavy gasoline cut HHCN desulfurized and stabilized (according to Example 3 of the present invention) makes it possible to produce a gasoline with a low sulfur content (15 ppm S) while decreasing the absolute loss of olefins compared to the heavy gasoline HCN desulfurized after the second desulfurization step (presented in Comparative Example 2). Indeed in example 2 the loss of olefins (in% by mass) between the first cut heavy HCN gasoline and the gasoline obtained after the second hydrodesulfurization step is 7.8% and in example 3 according to the invention the loss of olefins between the first heavy fuel cut HCN and the mixture of gasoline cuts intermediate fuel MCN and second cut heavy fuel HHCN desulfurized and stabilized is 6.6%. Thus, Example 3 according to the invention makes it possible to preserve 15% relative to the olefins present in the first heavy petrol HCN cut while producing a petrol with the same low sulfur content (15 ppm). The preservation of the olefins present in the first HCN heavy petrol cut has a positive impact on the octane ratings of the petrol produced.
    权利要求:
    Claims (16)
    [1" id="c-fr-0001]
    1) Process for desulfurization of a gasoline cut containing sulfur compounds, olefins and diolefins, comprising at least the following steps:
    a) the petrol is fractionated so as to recover a LCN light petrol cut and a first HCN heavy petrol cut;
    b) a first desulphurization step of the first heavy gasoline cut HCN is carried out in the presence of a hydrodesulfurization catalyst and hydrogen, at a temperature between 160 and 450 ° C, at a pressure between 0.5 and 8 MPa, with a liquid speed of between 0.5 and 20 h 1 and with a ratio between the flow of hydrogen expressed in normal m 3 per hour and the flow of feed to be treated expressed in m 3 per hour at the conditions standards between 50 Nm 3 / m 3 and 1000 Nm 3 / m 3 so as to produce a first desulphurization effluent;
    c) partially condensing the first desulphurization effluent from step b) so as to produce a gas phase consisting essentially of hydrogen and H 2 S and a liquid hydrocarbon phase HCN comprising dissolved H 2 S;
    d) the liquid hydrocarbon phase HCN is separated into an intermediate gasoline cut MCN and a second heavy gasoline cut HHCN;
    e) a second desulfurization step of the second heavy gasoline cut HHCN is carried out in the presence of a hydrodesulfurization catalyst and hydrogen, at a temperature between 160 and 450 ° C, at a pressure between 0.5 and 8 MPa, with a liquid speed of between 0.5 and 20 h 1 and with a ratio between the flow of hydrogen expressed in normal m 3 per hour and the flow of feed to be treated expressed in m 3 per hour at the conditions standards between 50 Nm 3 / m 3 and 1000 Nm 3 / m 3 so as to produce a second heavy gasoline cut, desulfurized HHCN, the process comprising:
    A step cj in which the dissolved H 2 S is separated from the HCN liquid hydrocarbon phase resulting from step c) in order to produce a HCN liquid hydrocarbon phase with a low content of dissolved H 2 S and said HCN liquid hydrocarbon phase with low dissolved H 2 S content being treated in step d), or • a step dj in which the dissolved H 2 S is separated from the intermediate gasoline cut MCN resulting from step d) to produce an intermediate gasoline cut MCN low in dissolved H 2 S.
    [2" id="c-fr-0002]
    2) Method according to claim 1, wherein step cj or dj is carried out by stripping with a gas.
    [3" id="c-fr-0003]
    3) Method according to claim 1, wherein step cj or dj is carried out by an absorption method.
    [4" id="c-fr-0004]
    4) Process according to claim 1, in which step cj or dj is carried out in a stabilization column configured to separate a hydrocarbon phase C4 ′ containing H 2 S and the liquid hydrocarbon phase HCN with a low content of H 2 S dissolved.
    [5" id="c-fr-0005]
    5) Method according to claim 1, in which steps cj and d) are carried out concomitantly in a fractionation column configured to separate:
    • a gas phase containing essentially H 2 S which is drawn off at the top of the column;
    • the intermediate gasoline cup MCN which is drawn laterally below the head of the column;
    • the second HHCN heavy fuel cut which is drawn off at the bottom of the column.
    [6" id="c-fr-0006]
    6) Method according to claim 1, in which the steps cj and d) are carried out concomitantly in a fractionation column configured to separate:
    • a gas phase containing hydrocarbons and H 2 S at the top of the column;
    • the second HHCN heavy fuel cut which is drawn off at the bottom of the column;
    and in which said gaseous phase is cooled and condensed so as to produce a gas flow essentially containing H 2 S and the intermediate gasoline cut MCN.
    [7" id="c-fr-0007]
    7) The method of claim 6, wherein the intermediate gasoline cut MCN is sent to a stabilization column.
    [8" id="c-fr-0008]
    8) Method according to one of the preceding claims, wherein the intermediate gasoline cut MCN has a temperature difference ΔΤ between the points at 5% and 95% of distilled mass which is less than or equal to 75 ° C.
    [9" id="c-fr-0009]
    9) Method according to claim 8, wherein the temperature difference ΔΤ between the points at 5% and 95% of the distilled mass of the intermediate gasoline cut MCN is between 20 and 65 ° C.
    [10" id="c-fr-0010]
    10) Method according to one of the preceding claims, wherein the second heavy gasoline cut desulfurized HHCN from step e) is sent to a stabilization column.
    [11" id="c-fr-0011]
    11) Method according to one of the preceding claims, in which the intermediate gasoline cut MCN is treated in a step f) of hydrodesulfurization.
    [12" id="c-fr-0012]
    12) Method according to claim 11, wherein the intermediate gasoline cut MCN desulfurized from step f) is sent to a stabilization column.
    [13" id="c-fr-0013]
    13) Method according to one of claims 1 to 10, wherein the intermediate gasoline cut MCN is treated in a liquid / liquid extraction process or extractive distillation or adsorption so as to produce an intermediate gasoline cut MCN at low content of thiophenic sulfur compounds.
    [14" id="c-fr-0014]
    14) Method according to one of the preceding claims, wherein before step a), the gasoline is treated in the presence of hydrogen and a selective hydrogenation catalyst so as to at least partially hydrogenate the diolefins and achieve a reaction for weighing down a portion of the sulfur-containing compounds, step a) being carried out at a temperature between 50 and 250 ° C at a pressure between 0.4 and 5 MPa, with a space velocity between 0, 5 and 20 h 1 and with a ratio between the hydrogen flow rate expressed in normal m3 per hour and the charge flow rate to be treated expressed in m 3 per hour at standard conditions between 2 Nm 3 / m 3 and 100 Nm 3 / m 3 .
    [15" id="c-fr-0015]
    15) Method according to one of the preceding claims, wherein the hydrodesulfurization catalysts of steps b) and e) comprise at least one element of group VIII, at least one element of group Vlb and a support.
    [16" id="c-fr-0016]
    16) Method according to one of the preceding claims, wherein the gasoline cut comes from a catalytic or thermal cracking unit.
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    EP3283601B1|2019-04-10|Method for sweetening an olefinic petrol of sulphide-type compounds
    EP1370630B1|2004-10-13|Method for producing desulphurised petrol from a petroleum fraction containing cracked petrol
    CN107868677B|2022-03-15|Process for treating gasoline by separation into three fractions
    EP2796196B1|2019-06-19|Catalytic adsorber for arsenic collection and selective hydrodesulphurisation of gasoline
    WO2021185658A1|2021-09-23|Method for producing a gasoline having a low sulfur and mercaptan content
    FR3030563A1|2016-06-24|PROCESS FOR SOFTENING OF SULFIDE COMPOUNDS OF AN OLEFINIC ESSENCE
    FR3007416A1|2014-12-26|PROCESS FOR PRODUCING LOW SULFUR AND MERCAPTAN GASOLINE
    同族专利:
    公开号 | 公开日
    KR102344827B1|2021-12-28|
    EP3299441B1|2019-01-30|
    KR20180034257A|2018-04-04|
    CN107868677A|2018-04-03|
    US10703997B2|2020-07-07|
    BR102017020169B1|2022-02-15|
    US20180086989A1|2018-03-29|
    ES2722652T3|2019-08-14|
    EP3299441A1|2018-03-28|
    PL3299441T3|2019-08-30|
    RU2017133255A|2019-03-25|
    RU2017133255A3|2020-12-01|
    JP2018053246A|2018-04-05|
    MX2017012339A|2018-09-26|
    BR102017020169A2|2018-05-02|
    RU2739989C2|2020-12-30|
    FR3056599B1|2018-09-28|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR2811328A1|2000-07-06|2002-01-11|Inst Francais Du Petrole|Hydrodesulfuration of petrol fractions comprises two stages of desulfuration with an intermediate elimination of hydrogen sulfide|
    US20060096893A1|2004-11-10|2006-05-11|Petroleo Brasileiro S.A. - Petrobras|Process for selective hydrodesulfurization of naphtha|
    FR3014896A1|2013-12-18|2015-06-19|IFP Energies Nouvelles|PROCESS FOR HYDRODESULFURIZATION OF HYDROCARBON CUT|
    DK29598A|1998-03-04|1999-09-05|Topsoe Haldor As|Process for desulphurizing FCC heavy gasoline|
    US7419586B2|2004-12-27|2008-09-02|Exxonmobil Research And Engineering Company|Two-stage hydrodesulfurization of cracked naphtha streams with light naphtha bypass or removal|
    FR3000964B1|2013-01-14|2016-01-01|IFP Energies Nouvelles|PROCESS FOR PRODUCING LOW SULFUR CONTENT|
    EP2816094B1|2013-06-19|2020-04-29|IFP Energies nouvelles|Method for producing gasoline with low sulphur and mercaptan content|
    FR3020376B1|2014-04-28|2017-10-20|Ifp Energies Now|PROCESS FOR PRODUCING LOW TEMPERATURE GASOLINE IN SULFUR AND MARCAPTANS|CN108865246B|2018-07-03|2021-04-02|中国石油化工股份有限公司|Method for removing volatile sulfide in mixed hydrocarbon|
    CN111068589B|2018-10-22|2021-08-31|中国石油化工股份有限公司|Liquid-phase hydrogenation system and liquid-phase hydrogenation method|
    FR3099172B1|2019-07-23|2021-07-16|Ifp Energies Now|PROCESS FOR TREATING A GASOLINE BY SEPARATION IN THREE CUTS|
    CN111575045A|2020-05-26|2020-08-25|中国海洋石油集团有限公司|Method for reducing benzene and increasing aromatic hydrocarbon yield of desulfurized gasoline|
    法律状态:
    2017-09-14| PLFP| Fee payment|Year of fee payment: 2 |
    2018-03-30| PLSC| Publication of the preliminary search report|Effective date: 20180330 |
    2018-09-17| PLFP| Fee payment|Year of fee payment: 3 |
    2019-09-25| PLFP| Fee payment|Year of fee payment: 4 |
    2020-09-28| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1659016|2016-09-26|
    FR1659016A|FR3056599B1|2016-09-26|2016-09-26|PROCESS FOR TREATING GASOLINE BY SEPARATING INTO THREE CUTS|FR1659016A| FR3056599B1|2016-09-26|2016-09-26|PROCESS FOR TREATING GASOLINE BY SEPARATING INTO THREE CUTS|
    EP17189530.3A| EP3299441B1|2016-09-26|2017-09-06|Method for treating a gasoline by separation into three cuts|
    ES17189530T| ES2722652T3|2016-09-26|2017-09-06|Process of treatment of a gasoline by separation in three cuts|
    PL17189530T| PL3299441T3|2016-09-26|2017-09-06|Method for treating a gasoline by separation into three cuts|
    BR102017020169-4A| BR102017020169B1|2016-09-26|2017-09-21|Process for the desulfurization of gasoline containing sulfur compounds, olefins and diolefins comprising fractionation into three cuts|
    KR1020170122002A| KR102344827B1|2016-09-26|2017-09-21|Process for the treatment of a gasoline by separation into three cuts|
    JP2017182262A| JP2018053246A|2016-09-26|2017-09-22|Gasoline processing method by separation to 3 fractions|
    RU2017133255A| RU2739989C2|2016-09-26|2017-09-25|Benzene processing method by dividing into three fractions|
    US15/715,711| US10703997B2|2016-09-26|2017-09-26|Process for the treatment of a gasoline by separation into three cuts|
    CN201710881170.9A| CN107868677B|2016-09-26|2017-09-26|Process for treating gasoline by separation into three fractions|
    MX2017012339A| MX2017012339A|2016-09-26|2017-09-26|Method for treating a gasoline by separation into three cuts.|
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