EP0922747B1 - Process for isomerisation of C5-C8 paraffinic fractions rich in paraffins with more than seven carbon atoms - Google Patents

Process for isomerisation of C5-C8 paraffinic fractions rich in paraffins with more than seven carbon atoms Download PDF

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Publication number
EP0922747B1
EP0922747B1 EP98402869A EP98402869A EP0922747B1 EP 0922747 B1 EP0922747 B1 EP 0922747B1 EP 98402869 A EP98402869 A EP 98402869A EP 98402869 A EP98402869 A EP 98402869A EP 0922747 B1 EP0922747 B1 EP 0922747B1
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Prior art keywords
process according
weight
hydrogen
feed
carbon atoms
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German (de)
French (fr)
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EP0922747A1 (en
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Eric Benazzi
Hervé Cauffriez
Olivier Clause
Jean-François Joly
Christine Travers
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IFP Energies Nouvelles IFPEN
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Classifications

    • 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
    • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G11/10—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with stationary catalyst bed
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
    • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
    • C10G45/60—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used
    • C10G45/62—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins characterised by the catalyst used containing 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
    • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G11/02—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils characterised by the catalyst used
    • C10G11/08—Halides
    • 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
    • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
    • C10G2300/10—Feedstock materials
    • C10G2300/1037—Hydrocarbon fractions

Definitions

  • the present invention relates to an isomerization process in the presence of hydrogen (also sometimes called hydro-isomerization process), of a filler comprising in major part of normal paraffins (also called n-paraffins or normal paraffins) containing 5 to 8 carbon atoms molecule.
  • hydrogen also sometimes called hydro-isomerization process
  • a filler comprising in major part of normal paraffins (also called n-paraffins or normal paraffins) containing 5 to 8 carbon atoms molecule.
  • n-butane normal butane
  • isobutane which can be used in different applications.
  • Isobutane can also, after dehydrogenation, be used in the reaction etherification with methanol or ethanol.
  • ethers thus obtained - methyl tertio butyl ether (MTBE) or ethyl tertio butyl ether (ETBE) - have high octane numbers and can be directly incorporated into petrol.
  • MTBE methyl tertio butyl ether
  • ETBE ethyl tertio butyl ether
  • the temperature of reaction is usually greater than 200 ° C and often 300 ° C and the ratio of the number of moles of hydrogen over the number of moles of hydrocarbons is greater than 1.
  • Patent FR 2735993 describes a catalyst and its use in processes isomerization of normal paraffins containing from 4 to 6 carbon atoms.
  • This catalyst contains at least one halogen, preferably this halogen is chlorine, less a group VIII metal and a shaped support comprising alumina gamma and / or optionally eta alumina, the catalyst being characterized in that the smallest average dimension of said support is about 0.8 to 2 mm, preferably approximately 1 to 1.8 mm, and in that its chlorine content is approximately 4.5 to 15% by weight, preferably about 5 to 12% by weight.
  • This catalyst is prepared by halogenation of a catalyst containing at least one group VIII metal on an alumina support. Once once the metal has been deposited, the support can undergo an activation treatment in air and / or under nitrogen.
  • Patent EP 0 495 277 describes a catalyst and its use in isomerization processes normal paraffins containing 4 to 7 carbon atoms.
  • This catalyst contains a halogen, preferably this halogen is the Chlorine, a platinum group metal and a shaped support comprising alumina, catalyst being characterized in that its content of chlorine is 1 to 15% by weight and its platinum group metal content is from 0.01 to 2% by weight.
  • the reaction isomerization takes place at a temperature between 125 and 165 ° C.
  • a halogenated catalyst can also be prepared from a support, shaped and treated with steam.
  • a catalyst is the subject of a patent application on the part of of the plaintiff, filed on the same day as this application, and in which is describes a catalyst containing at least one halogen, at least one metal from group VIII and a support comprising gamma alumina and / or eta alumina, shaped and treated under a stream of gas containing water vapor.
  • the present invention relates to a process for isomerization in the presence of hydrogen of a filler mainly comprising normal paraffins containing from 5 to 8 atoms of carbon per molecule, characterized in that the sum of the normal paraffin contents at 7 and 8 carbon atoms per molecule contained in the charge is between 2 and 90% weight relative to the load, and in that said load is treated in at least one reaction zone, containing at least one fixed bed catalyst, said catalyst comprising a support, at least one halogen and at least one group VIII metal, the reaction being carried out at a temperature between 70 and 95 ° C.
  • the present invention also relates to a method for increasing the index octane from a petroleum cut comprising normal paraffins containing from 5 to 8 carbon atoms per molecule.
  • the present invention makes it possible in particular to overcome the aforementioned drawbacks.
  • the method according to the invention makes it possible to convert charges for which the sum of the normal paraffin contents at 7 and at 8 carbon atoms per molecule contained in said charge is between 2 and 90 % by weight, preferably between 5 and 90% by weight, more preferably between 20 and 90% weight and very preferably between 40 and 90% by weight.
  • the method according to the present invention allows, from a load to be treated comprising normal paraffins containing 5 to 8 carbon atoms per molecule, to obtain a paraffin yield branched containing at least 5 carbon atoms per molecule greater than 85% by weight.
  • the process according to the present invention uses at least one reaction zone which includes at least one reactor, preferably containing at least one solid catalyst acid in a fixed bed, the reaction temperature is between 70 and 95 ° C.
  • the catalyst used comprises a support, preferably based on alumina, containing at least one halogen, the halogen content being between 0.1 and 15% by weight, and at least one Group VIII metal.
  • a catalyst based on chlorinated alumina preferably based on chlorinated alumina.
  • the catalyst used in the process according to the invention contains at least one metal of the group VIII on a support preferably based on alumina, on this support is deposited at least one halogen, preferably chosen from the group formed by fluorine, chlorine, bromine and iodine, more preferably the halogen is chlorine. Content halogen is between 0.1 and 15% by weight, preferably between 4 and 12%. in weight
  • the support of the catalyst preferably comprises essentially alumina.
  • the alumina preferably used in the process according to the invention can be of gamma alumina and / or optionally eta alumina (i.e. be either gamma alumina, or eta alumina, or a mixture of these two aluminas).
  • the alumina of the support comprises between 50 and 100% by weight, preferably between 80 and 100% by weight of alumina eta, more preferred 80 to 95% by weight of alumina eta, the balance being gamma alumina.
  • the smallest average size of the catalyst support is about 0.8 to 2 mm, of preferably about 1 to 1.8 mm.
  • said support is formed essentially of beads with an average diameter of about 0.8 to 2 mm, preferably about 1 to 1.8 mm, or well said support is formed essentially of extrudates whose smallest dimension is about 0.8 to 2 mm, preferably about 1 to 1.8 mm, i.e. the extrudates have was shaped using any extrusion technique known to those skilled in the art, such as for example a die with a diameter of about 0.8 to 2 mm, preferably about 1 to 1.8 mm.
  • the gamma alumina possibly present in the support of the catalyst has a specific surface of approximately 150 to 300 m 2 / g and preferably of approximately 180 to 250 m 2 / g, and a total pore volume generally of approximately 0, 4 to 0.8 cm 3 / g and preferably about 0.45 to 0.7 cm 3 / g.
  • the alumina was optionally present in the catalyst support has a specific surface of approximately 400 to 600 m 2 / g and preferably of approximately 420 to 550 m 2 / g, and a total pore volume of approximately 0.3 at 0.5 cm 3 / g and preferably about 0.35 to 0.45 cm 3 / g.
  • the metal of group VIII is chosen from the group formed by iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably chosen in the group formed by platinum, palladium and nickel.
  • the content is about 0.05 to 2% by weight and so preferred about 0.1 to 1.5% by weight.
  • the weight content is from about 0.1 to 10% by weight and preferably from about 0.2 to 6% weight.
  • the preparation of the catalyst is generally carried out by shaping the support. Says it support shaped suddenly can optionally undergo a treatment under steam at high temperature before or after the deposition of at least one group VIII metal. A halogenation, preferably chlorination, is then carried out. It is also possible and preferred to carry out an activation step under hydrogen, before said step halogenation.
  • these two types of aluminas are preferably mixed and shaped together, according to any technique known to those skilled in the art, for example by extrusion through a die, by pelleting or by coating.
  • the smallest dimension of the geometric shape described by the support after shaping is approximately 0.8 to 2 mm, preferably approximately 1 to 1.8 mm, which makes it possible to obtain , during the halogenation stage of the support, a sufficient halogen content for a reduced halogenation period.
  • the support preferably undergoes a treatment at high temperature under water vapor.
  • the hydrothermal treatment is generally carried out for 0.5 to 6 hours, for example at a temperature of around 200 to 700 ° C. under a gas flow, for example air and / or nitrogen.
  • the gas must contain water, for example at contents of about 0.2% to 100% by volume and preferably about 0.3% to 20% by volume.
  • the activation of alumina by water vapor makes it possible to obtain much more acidic catalysts and therefore much more active in isomerization.
  • At least one hydrogenating metal from group VIII chosen from the group formed by iron, the cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably chosen from the group formed by platinum, palladium, and nickel, is then deposited on the support by any technique known to those skilled in the art, by example by anion exchange in the form of hexachloroplatinic acid in the case of platinum or in the form of chloride in the case of palladium. Hydrothermal treatment can be made after depositing the metal on the support.
  • the support comprising the deposited metal can then optionally undergo a treatment under hydrogen which makes it possible to obtain an active metallic phase.
  • the procedure of this hydrogen treatment for example includes a slow rise in temperature under hydrogen flow up to the maximum reduction temperature which is around 300 to 700 ° C, and preferably between 340 to 680 ° C, followed by maintaining this temperature, generally for 1 to 6 hours, preferably for 1.5 to 4.5 hours.
  • the halogenation step can be carried out according to any known technique of the skilled person.
  • the halogen preferably chlorine
  • Halogenation, preferably chlorination, alumina is carried out directly in the isomerization unit before injection of the load to be treated, or off site: in a separate unit, intended for halogenation.
  • the halogenation can be carried out by any halogenating carbon agent, of preferably chlorinating agent, known to those skilled in the art.
  • halogen preferably chlorine
  • the reduction treatment under hydrogen can take place outside the unit (e.g. situ "), which implies taking special precautions for the transport of said catalyst up to said unit, or else said treatment can take place within the unit ("in-situ") just before the use of said catalyst.
  • the present invention relates to a process for the isomerization of a charge mainly comprising normal paraffins containing from 5 to 8 carbon atoms per molecule, characterized in that the sum of the contents of normal paraffins at 7 and 8 carbon atoms per molecule contained in the charge is between 2 and 90% by weight, preferably between 5 and 90% by weight, more preferably between 20 and 90% by weight, and very preferably between 40 and 90% by weight relative to the feed, and in that said feed is treated in at least one reaction zone, preferably containing at least one fixed bed catalyst, said catalyst comprising a support, at least one halogen and at least one group VIII metal, the reaction being carried out at a temperature of between 70 and 95 ° C.
  • the feed to be treated preferably containing at least one halogenated compound, more preferably a chlorinated compound, the pon content of which derale in said charge is between 50 and 2000 ppm, and most often between 50 and 300 ppm, for example perchlorethylene C 2 Cl 4 ,
  • Two embodiments of the invention can be considered, they will be chosen in function of the amount of excess hydrogen relative to the amount of hydrogen consumed by hydrogenation reactions, the opening of naphthenic cycles and paraffin cracking. This can also be expressed by the ratio R of the number of moles of hydrogen on the number of moles of hydrocarbons in the effluent leaving the reactor.
  • a small excess of hydrogen is used, so that the ratio R of the number of moles of hydrogen to the number of moles of hydrocarbons calculated on the basis of the composition of the effluent leaving the reactor either between 0.06 and 0.3, preferably 0.06 and 0.2. In this case it is not necessary to recycle the hydrogen not consumed towards the inlet of the reactor. We then operate at "Lost hydrogen".
  • the ratio R of the number of moles of hydrogen to the number of moles of hydrocarbons calculated on the basis of the composition of the effluent leaving the reactor is then understood between 0.3 and 10, preferably between 0.3 and 5, and even more preferably between 0.5 and 3.
  • the excess hydrogen is recycled to the inlet of the reactor for example by means of a gas-liquid separation tank and a recycling compressor. according to this mode of the invention it is possible to adjust the partial pressure of hydrogen in a wider range than in the first embodiment.
  • the hourly volume velocity (PPH) defined as the mass flow rate of feed to be treated per mass of catalyst and per hour is approximately 0.2 to 10 kg of feed per kg of catalyst and per hour (0.2 to 10 h -1 ), preferably around 0.3 to 5 kg of feed per kg of catalyst per hour (0.3 to 5 h -1 ) and even more preferably between 0.5 and 2 kg of feed per kg of catalyst per hour (0.5 to 2 h -1 ).
  • the reactor pressure is about 0.1 to 10 MPa relative, preferably about 0.5 to 8 MPa relative, more preferably between 2 and 5 MPa.
  • the reactor temperature is between 70 and 95 ° C.
  • a catalyst comprising a support, at least one halogen and at least one metal of group VIII, under the operating conditions indicated above leads to a surprisingly in obtaining high levels of conversion of C5-C8 n-paraffins, and more particularly n-heptane while retaining high yields of isomers, that is to say in light gasoline essentially consisting of hydrocarbons containing 5 to 8 carbon atoms.
  • This catalyst therefore makes it possible to obtain a low cracking rate.
  • the method according to the invention can treat all types of charges comprising in major part of normal paraffins containing from 5 to 8 carbon atoms, naphthenes, aromatic (in amounts usually less than 10% by weight). More specifically, the process according to the invention makes it possible to treat paraffinic cuts including the chain contains 5 to 8 carbon atoms, and in which the sum of the paraffin contents normal to 7 and 8 carbon atoms per molecule included in the section is included between 2 to 90% by weight, preferably between 5 and 90% by weight, more preferably between 20 and 90% by weight and very preferably from 40 to 90% by weight.
  • the charges of the process according to the invention are free of water, oxygen, sulfur and more generally all compounds known to be poisons or inhibitors of alumina catalysts halogenated.
  • a reactor with a volume of 200 ml is used, fed in upflow mode fluids by the mixture constituted by the charge to be treated and by the hydrogen.
  • the effluent leaving the reactor is cooled and then analyzed by vapor phase chromatography.
  • an industrial catalyst based on chlorinated alumina sold is used. by the company Procatalyse under the reference IS 612A.
  • a reactor with a volume of 200 ml is also used, fed in flow mode ascending of fluids by the mixture constituted by the load to be treated and by hydrogen.
  • the effluent leaving the reactor is cooled and then analyzed by phase chromatography steam.
  • the operating conditions are as follows:
  • the reactor is supplied with a feed comprising hydrocarbons containing from 5 to 7 carbon atoms and 800 ppm by weight of perchlorethylene (C 2 Cl 4 ) at a flow rate of 87 g / h, the mass of the catalyst being of 86 g, the PPH is 1.01 h -1 .
  • the hydrogen flow rate is 4.5 10 -9 l / h.
  • the total pressure is 3 MPa relative.
  • isomerization 1 is carried out at a temperature of 105 ° C.
  • the ratio R1 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 0.14
  • isomerization 2 is carried out at 115 ° C. and the ratio R2 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 0.11.
  • Example 1 the same catalyst and the same reactor are used as in Example 1.
  • the reactor is supplied with a feed comprising hydrocarbons containing 5 to 7 carbon atoms and 800 ppm by weight of perchlorethylene (C2C14) at a flow rate of 84 g / h, the mass of the catalyst being 84 g, the PPH is 1 h-1 .
  • the hydrogen flow rate is 60 10 -9 l / h.
  • the total pressure is 3 MPa relative.
  • isomerization 3 is carried out at a temperature of 115 ° C.
  • the ratio R3 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 2.67
  • isomerization 4 is carried out at 130 ° C.
  • the ratio R4 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 2.56.
  • Example 2 corresponds to an isomerization process in which a large excess of hydrogen is used with respect to the feed to be converted.
  • the composition of the charge and the results obtained are illustrated by means of Table 2.
  • compounds Load (% by weight) After isomerization 3 (% by weight) After isomerization4 (% by weight) C2-C4 0.87 5.99 9.51 iC5 9.95 11,73 12.5 nC5 7.79 6.33 6.18 cyclopentane 0.62 0.62 0.62 IC6 9.50 10.40 11,01 nC6 2.97 2.07 2.02 cyclohexane 5.10 3.79 3.19 methylcyclopentane 2.32 2.47 2.67 benzene 0.17 0 0 nC7 55.41 13.63 9.15 IC7 5.30 42.97 43,15 Isomerization 1 Isomerization 2 nC5 conversion 18.8% 20.7% nC6 conversion 30.3% 32% nC7 conversion 75.4% 83.5% C5 + efficiency 94
  • Table 2 also illustrates the fact that 130 ° C is an appreciably low temperature. away from the maximum temperature compatible with obtaining high yields in isomers, in particular if it is estimated that a cracking rate in light products of 10% is the upper acceptable limit. In fact, at 130 ° C, 8.7% of products are already obtained light formed by cracking, therefore a yield of branched paraffins containing from 5 to 7 91.3% carbon atoms.
  • the catalyst used in Example 3 is manufactured as follows: gamma alumina is formed by extrusion through a die with a diameter of 1.2 mm. The solid thus formed is treated at 500 ° C with air containing 3% by volume of water vapor. 0.2% of platinum-shaped alumina is deposited on said alumina by ion exchange with hexachloroplatinic acid in the presence of HCl as a competing agent. The solid obtained is reduced under hydrogen at 400 ° C. The solid obtained is then chlorinated, at a temperature of 280 ° C., by injection of carbon tetrachloride under a stream of nitrogen.
  • the load to be treated consists of approximately 10% by weight of normal paraffins with 5 carbon atoms, 10% by weight of normal paraffins with 6 carbon atoms, 65% by weight of normal paraffins with 7 carbon atoms and 8% by weight of naphthenes containing 6 carbon atoms.
  • Said feed containing 100 ppm of carbon tetrachloride (CCl 4 ) expressed by weight of chlorine to maintain the chlorine content of the catalyst used.
  • the isomerization operating conditions are as follows: the reactor temperature is 110 ° C., the total pressure of 3 relative MPa, the PPH of 1 h -1 and the ratio R5 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the reactor outlet is equal to 0.47.

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Description

La présente invention concerne un procédé d'isomérisation en présence d'hydrogène (également parfois appelé procédé d'hydro-isomérisation), d'une charge comprenant en majeur partie des paraffines normales (également appelées n-paraffines ou normales paraffines) contenant de 5 à 8 atomes de carbone molécule.The present invention relates to an isomerization process in the presence of hydrogen (also sometimes called hydro-isomerization process), of a filler comprising in major part of normal paraffins (also called n-paraffins or normal paraffins) containing 5 to 8 carbon atoms molecule.

La suppression des alkyles de plomb dans les essences automobiles, notamment à des fins de protection de l'environnement, a généré un développement des procédés de production de paraffines ramifiées qui ont un meilleur indice d'octane que les composés linéaires, et en particulier du procédé d'isomérisation des paraffines normales en paraffines ramifiées. Ce procédé revêt actuellement une importance croissante dans l'industrie pétrolière.The removal of lead alkyls from motor fuels, in particular for environmental protection, generated a development of production processes branched paraffins which have a better octane number than the linear compounds, and in particular of the process for isomerization of normal paraffins into branched paraffins. This process is currently of increasing importance in the petroleum industry.

L'isomérisation du n-butane (butane normal) permet de produire de l'isobutane qui peut être utilisé dans différentes applications. Parmi ces applications on peut citer : les procédés d'alkylation des oléfines légères pour produire des coupes paraffiniques contenant de 5 à 12 atomes de carbone par molécule. Cette alkylation est réalisée par au moins une isoparaffine, elle permet d'obtenir des coupes qui présentent de hauts indices d'octane. L'isobutane peut également, après déshydrogénation, être utilisé dans la réaction d'éthérification par le méthanol ou l'éthanol. Les éthers ainsi obtenus -le méthyl tertio butyl éther (MTBE) ou l'éthyl tertio butyl éther (ETBE)- ont de hauts indices d'octane et peuvent être directement incorporés à l'essence.The isomerization of n-butane (normal butane) makes it possible to produce isobutane which can be used in different applications. Among these applications, we can cite: alkylation of light olefins to produce paraffinic cuts containing from 5 to 12 carbon atoms per molecule. This alkylation is carried out by at least one isoparaffin, it allows to obtain cuts which have high octane numbers. Isobutane can also, after dehydrogenation, be used in the reaction etherification with methanol or ethanol. The ethers thus obtained - methyl tertio butyl ether (MTBE) or ethyl tertio butyl ether (ETBE) - have high octane numbers and can be directly incorporated into petrol.

Le procédé d'isomérisation des paraffines contenant 5 et 6 atomes de carbone par molécule conduit également à la production de bases essences à hauts indices d'octane qui peuvent être directement incorporées aux fractions essence. Ce dernier procédé a fait l'objet de nombreux travaux, trois types de catalyseurs différents sont traditionnellement utilisés pour réaliser cette réaction d'isomérisation :

  • les catalyseurs de type Friedel et Crafts, tels que les catalyseurs contenant du chlorure d'aluminium, qui sont utilisés à basses températures (environ 20 à 130°C),
  • les catalyseurs à base de métaux du groupe VIII de la classification périodique des éléments (Handbook of Chemistry and Physics, 45 ème édition, 1964-1965) déposés sur alumine et contenant généralement un halogène, qui sont utilisés à des températures moyennes (environ 110 à 160°C). Les brevets US-A-2.906.798, US-A-2.993.398, US-A-3.791.960, US-A-4.113.789, US-A-4.149.993, US-A-4.804.803 décrivent, par exemple, ce type de catalyseurs,
  • les catalyseurs zéolithiques comprenant un métal du groupe VIII déposé sur une zéolithe, qui sont utilisés à des températures élevées (de 250 °C à 350 °C), ces catalyseurs conduisent à l'obtention d'un mélange d'hydrocarbures ayant un indice d'octane amélioré mais moins bon que celui obtenu par les procédés utilisant les catalyseurs cités ci-dessus, cependant ils présentent l'avantage d'être plus faciles à mettre en oeuvre et plus résistants aux poisons. Leur faible acidité ne permet pas de les employer pour l'isomérisation du n-butane. Le brevet US-A- 4.727.217 décrit ce type de catalyseurs.
The process for isomerizing paraffins containing 5 and 6 carbon atoms per molecule also leads to the production of gasoline bases with high octane numbers which can be directly incorporated into the gasoline fractions. This latter process has been the subject of numerous works, three different types of catalyst are traditionally used to carry out this isomerization reaction:
  • Friedel and Crafts type catalysts, such as catalysts containing aluminum chloride, which are used at low temperatures (around 20 to 130 ° C),
  • catalysts based on metals from group VIII of the periodic table of elements (Handbook of Chemistry and Physics, 45 th edition, 1964-1965) deposited on alumina and generally containing a halogen, which are used at average temperatures (approximately 110 to 160 ° C). Patents US-A-2,906,798, US-A-2,993,398, US-A-3,791,960, US-A-4,113,789, US-A-4,149,993, US-A-4,804.803 describe , for example, this type of catalyst,
  • zeolitic catalysts comprising a group VIII metal deposited on a zeolite, which are used at high temperatures (from 250 ° C to 350 ° C), these catalysts lead to the production of a mixture of hydrocarbons having an index d octane improved but less good than that obtained by the processes using the catalysts mentioned above, however they have the advantage of being easier to use and more resistant to poisons. Their low acidity does not allow them to be used for the isomerization of n-butane. US-A-4,727,217 describes this type of catalyst.

Les procédés actuels d'isomérisation des paraffines contenant 5 et 6 atomes de carbone utilisant des catalyseurs de type alumine chlorée et comprenant du platine sont des catalyseurs à haute activité. Ces procédés sont utilisés sans recyclage (en anglais "once through"), ou avec un recyclage partiel après fractionnement des paraffines normales non converties, ou encore avec un recyclage total après passage sur des systèmes de tamis moléculaires en phase liquide. Ces procédés conduisent à l'obtention d'une base pour carburants ne contenant pas d'aromatiques et dont l'indice d'octane recherche (en anglais Research Octane Number : R.O.N.) est généralement compris entre 82 et 88, le procédé d'isomérisation des paraffines normales utilisé comprend ou non un recyclage.Current processes for isomerization of paraffins containing 5 and 6 carbon atoms using chlorinated alumina type catalysts and comprising platinum are high activity catalysts. These processes are used without recycling (in English "ounce through "), or with partial recycling after fractionation of normal paraffins not converted, or with total recycling after passing through sieve systems molecular in the liquid phase. These methods lead to obtaining a base for fuels not containing aromatics and whose octane number research (in English Research Octane Number: R.O.N.) is generally between 82 and 88, the process Isomerization of normal paraffins used may or may not include recycling.

De nombreux brevets ont pour objet des catalyseurs monométalliques à base de platine déposé sur une alumine halogénée, et leur utilisation dans des procédés d'isomérisation des paraffines normales. On peut citer le brevet US-A-3 963 643, qui impose un traitement par un composé de type Friedel et Crafts suivi par un traitement avec un composé chloré comportant au moins deux atomes de chlore, ce traitement s'appliquant plus particulièrement aux hydrocarbures à chaine linéaire contenant de 4 à 6 atomes de carbone. Le brevet US-A-5 166 121 décrit un catalyseur comprenant de l'alumine gamma mise en forme sous forme de billes et comportant entre 0,1 et 3,5 % d'halogène sur le support. La teneur en halogène, de préférence en chlore, déposée sur le support est extrêmement faible.Numerous patents relate to platinum-based monometallic catalysts deposited on a halogenated alumina, and their use in isomerization processes of normal paraffins. Mention may be made of US-A-3,963,643, which requires treatment by a Friedel and Crafts type compound followed by treatment with a chlorine compound containing at least two chlorine atoms, this treatment applying more particularly to straight chain hydrocarbons containing from 4 to 6 atoms of carbon. US-A-5,166,121 describes a catalyst comprising gamma alumina shaped into beads and comprising between 0.1 and 3.5% halogen on the support. The halogen content, preferably chlorine, deposited on the support is extremely weak.

Un inconvénient majeur de ces procédés, selon l'état actuel des connaissances mises à la disposition du public, est qu'ils ne permettent pas de traiter convenablement des charges présentant des teneurs en paraffines normales contenant au moins 7 atomes de carbone par molécule supérieures à environ 2 % en poids. Les conditions opératoires connues pour favoriser l'isomérisation des coupes contenant des paraffines à 5 et 6 atomes de carbone par molécule conduisent à des taux de craquage des paraffines contenant au moins 7 atomes de carbone et plus par molécule trop importants (de l'ordre de 20 à 80% pour les paraffines en C7). L'examen de l'art antérieur montre que des catalyseurs ont été étudiés pour l'isomérisation des paraffines normales à 7 atomes de carbone. Dans ces procédés, la température de réaction est généralement supérieure à 200°C et souvent à 300°C et le rapport du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures est supérieur à 1. Ces conditions opératoires ne favorisent pas l'obtention de paraffines très ramifiées. Les données d'équilibre thermodynamique montrent en effet que le taux de ramification des paraffines diminue quand la température augmente.A major drawback of these methods, according to the current state of knowledge brought to light. available to the public, is that they do not allow for proper handling of charges having normal paraffin contents containing at least 7 carbon atoms per molecule greater than about 2% by weight. The known operating conditions for promote the isomerization of sections containing paraffins with 5 and 6 carbon atoms per molecule lead to cracking rates of paraffins containing at least 7 carbon atoms and more per molecule too large (on the order of 20 to 80% for paraffins in C7). Examination of the prior art shows that catalysts have been studied for isomerization normal paraffins with 7 carbon atoms. In these processes, the temperature of reaction is usually greater than 200 ° C and often 300 ° C and the ratio of the number of moles of hydrogen over the number of moles of hydrocarbons is greater than 1. These operating conditions do not favor obtaining highly branched paraffins. The thermodynamic equilibrium data indeed show that the branching rate of paraffins decrease as the temperature increases.

Le brevet FR 2735993, décrit un catalyseur et son utilisation dans des procédés d'isomérisation des paraffines normales contenant de 4 à 6 atomes de carbone. Ce catalyseur contient au moins un halogène, de façon préférée cet halogène est le chlore, au moins un métal du groupe VIII et un support mis en forme comprenant de l'alumine gamma et/ou éventuellement de l'alumine êta, le catalyseur étant caractérisé en ce que la plus petite dimension moyenne dudit support est d'environ 0,8 à 2 mm, de préférence d'environ 1 à 1,8 mm, et en ce que sa teneur en chlore est d'environ 4,5 à 15 % en poids, de préférence d'environ 5 à 12% en poids. Ce catalyseur est préparé par halogénation d'un catalyseur contenant au moins un métal du groupe VIII sur un support d'alumine. Une fois le dépôt du métal effectué, le support peut subir un traitement d'activation sous air et/ou sous azote.Patent FR 2735993 describes a catalyst and its use in processes isomerization of normal paraffins containing from 4 to 6 carbon atoms. This catalyst contains at least one halogen, preferably this halogen is chlorine, less a group VIII metal and a shaped support comprising alumina gamma and / or optionally eta alumina, the catalyst being characterized in that the smallest average dimension of said support is about 0.8 to 2 mm, preferably approximately 1 to 1.8 mm, and in that its chlorine content is approximately 4.5 to 15% by weight, preferably about 5 to 12% by weight. This catalyst is prepared by halogenation of a catalyst containing at least one group VIII metal on an alumina support. Once once the metal has been deposited, the support can undergo an activation treatment in air and / or under nitrogen.

La publication EP 0 495 277 décrit un catalyseur et son utilisation dans des procédés d'isomérisation des paraffines normales contenant de 4 à 7 atomes de carbone. Ce catalyseur contient un halogène, de façon préférée cet halogène est le Chlore, un metal du groupe du platine et un support mis en forme comprenant de l'alumine, le catalyseur étant caractérisé en ce que sa teneur en chlore est de 1 à 15 % en poids et que sa teneur en métal du groupe du platine est de 0,01 à 2% en poids. La réaction d'isomérisation s'effectue à une température comprise entre 125 et 165°C.Publication EP 0 495 277 describes a catalyst and its use in isomerization processes normal paraffins containing 4 to 7 carbon atoms. This catalyst contains a halogen, preferably this halogen is the Chlorine, a platinum group metal and a shaped support comprising alumina, catalyst being characterized in that its content of chlorine is 1 to 15% by weight and its platinum group metal content is from 0.01 to 2% by weight. The reaction isomerization takes place at a temperature between 125 and 165 ° C.

Un catalyseur halogéné peut également être préparé à partir d'un support, mis en forme et traité à la vapeur d'eau. Un tel catalyseur fait l'objet d'une demande de brevet de la part de la demanderesse, déposée le même jour que la présente demande, et dans laquelle est décrit un catalyseur contenant au moins un halogène, au moins un métal du groupe VIII et un support comprenant de l'alumine gamma et/ou de l'alumine êta, mis en forme, et traité sous un flux de gaz contenant de la vapeur d'eau.A halogenated catalyst can also be prepared from a support, shaped and treated with steam. Such a catalyst is the subject of a patent application on the part of of the plaintiff, filed on the same day as this application, and in which is describes a catalyst containing at least one halogen, at least one metal from group VIII and a support comprising gamma alumina and / or eta alumina, shaped and treated under a stream of gas containing water vapor.

La présente invention concerne un procédé d'isomérisation en présence d'hydrogène d'une charge comprenant en majeure partie des paraffines normales contenant de 5 à 8 atomes de carbone par molécule, caractérisé en ce que la somme des teneurs en paraffines normales à 7 et à 8 atomes de carbone par molécule contenues dans la charge est comprise entre 2 et 90 % poids par rapport à la charge, et en ce que ladite charge est traitée dans au moins une zone réactionnelle, contenant au moins un catalyseur en lit fixe, ledit catalyseur comprenant un support, au moins un halogène et au moins un métal du groupe VIII, la réaction étant effectuée à une température comprise entre 70 et 95°C.The present invention relates to a process for isomerization in the presence of hydrogen of a filler mainly comprising normal paraffins containing from 5 to 8 atoms of carbon per molecule, characterized in that the sum of the normal paraffin contents at 7 and 8 carbon atoms per molecule contained in the charge is between 2 and 90% weight relative to the load, and in that said load is treated in at least one reaction zone, containing at least one fixed bed catalyst, said catalyst comprising a support, at least one halogen and at least one group VIII metal, the reaction being carried out at a temperature between 70 and 95 ° C.

La présente invention concerne également un procédé permettant d'augmenter l'indice d'octane d'une coupe pétrolière comprenant des paraffines normales contenant de 5 à 8 atomes de carbone par molécule. La présente invention permet en particulier de s'affranchir des inconvénients précités. En effet, le procédé selon l'invention permet de convertir des charges pour lesquelles la somme des teneurs en paraffines normales à 7 et à 8 atomes de carbone par molécule contenues dans ladite charge est comprise entre 2 et 90 % poids, de préférence entre 5 et 90 % poids, de manière plus préférée entre 20 et 90% poids et de façon très préférée entre 40 et 90 % poids. Le procédé selon la présente invention permet, à partir d'une charge à traiter comprenant des paraffines normales contenant de 5 à 8 atomes de carbone par molécule, d'obtenir un rendement en paraffines ramifiées contenant au moins 5 atomes de carbone par molécule supérieur à 85 % poids.The present invention also relates to a method for increasing the index octane from a petroleum cut comprising normal paraffins containing from 5 to 8 carbon atoms per molecule. The present invention makes it possible in particular to overcome the aforementioned drawbacks. Indeed, the method according to the invention makes it possible to convert charges for which the sum of the normal paraffin contents at 7 and at 8 carbon atoms per molecule contained in said charge is between 2 and 90 % by weight, preferably between 5 and 90% by weight, more preferably between 20 and 90% weight and very preferably between 40 and 90% by weight. The method according to the present invention allows, from a load to be treated comprising normal paraffins containing 5 to 8 carbon atoms per molecule, to obtain a paraffin yield branched containing at least 5 carbon atoms per molecule greater than 85% by weight.

Le procédé selon la présente invention utilise au moins une zone réactionnelle qui comprend au moins un réacteur contenant, de préférence, au moins un catalyseur solide acide en lit fixe, la température de réaction est comprise entre 70 et 95°C. Le catalyseur utlisé comprend un support, préférentiellement à base d'alumine, contenant au moins un halogène, la teneur en halogène étant comprise entre 0,1 et 15 % en poids, et au moins un métal du groupe VIII. Selon un mode de réalisation préféré de l'invention on utilise un catalyseur à base d'alumine chlorée.The process according to the present invention uses at least one reaction zone which includes at least one reactor, preferably containing at least one solid catalyst acid in a fixed bed, the reaction temperature is between 70 and 95 ° C. The catalyst used comprises a support, preferably based on alumina, containing at least one halogen, the halogen content being between 0.1 and 15% by weight, and at least one Group VIII metal. According to a preferred embodiment of the invention, a catalyst based on chlorinated alumina.

Le catalyseur utilisé dans le procédé selon l'invention contient au moins un métal du groupe VIII sur un support préférentiellement à base d'alumine, sur ce support est déposé au moins un halogène, préférentiellement choisi dans le groupe formé par le fluor, le chlore, le brome et l'iode, de manière plus préférée l'halogène est le chlore. La teneur en halogène est comprise entre 0,1 et 15 % en poids, de préférence entre 4 et 12%. en poids Le support du catalyseur comprend préférentiellement essentiellement de l'alumine. L'alumine utilisée préférentiellement dans le procédé selon l'invention peut être de l'alumine gamma et/ou éventuellement de l'alumine êta (c'est-à-dire être constituée soit d'alumine gamma, soit d'alumine êta, soit d'un mélange de ces deux alumines). Lorsque l'on ajoute de l'alumine gamma à l'alumine êta, l'alumine du support comprend entre 50 et 100 % en poids, de préférence entre 80 et 100 % en poids d'alumine êta, de manière plus préférée 80 à 95% poids d'alumine êta, le complément étant de l'alumine gamma. The catalyst used in the process according to the invention contains at least one metal of the group VIII on a support preferably based on alumina, on this support is deposited at least one halogen, preferably chosen from the group formed by fluorine, chlorine, bromine and iodine, more preferably the halogen is chlorine. Content halogen is between 0.1 and 15% by weight, preferably between 4 and 12%. in weight The support of the catalyst preferably comprises essentially alumina. The alumina preferably used in the process according to the invention can be of gamma alumina and / or optionally eta alumina (i.e. be either gamma alumina, or eta alumina, or a mixture of these two aluminas). When gamma alumina is added to the eta alumina, the alumina of the support comprises between 50 and 100% by weight, preferably between 80 and 100% by weight of alumina eta, more preferred 80 to 95% by weight of alumina eta, the balance being gamma alumina.

La plus petite dimension moyenne du support du catalyseur est d'environ 0,8 à 2 mm, de préférence d'environ 1 à 1,8 mm. De préférence, ledit support est formé essentiellement de billes de diamètre moyen d'environ 0,8 à 2 mm, de préférence d'environ 1 à 1,8 mm, ou bien ledit support est formé essentiellement d'extrudés dont la plus petite dimension est d'environ 0,8 à 2 mm, de préférence d'environ 1 à 1,8 mm, c'est-à-dire que les extrudés ont été mis en forme à partir de toute technique d'extrusion connue de l'homme du métier, comme par exemple une filière de diamètre d'environ 0,8 à 2 mm, de préférence d'environ 1 à 1,8 mm.The smallest average size of the catalyst support is about 0.8 to 2 mm, of preferably about 1 to 1.8 mm. Preferably, said support is formed essentially of beads with an average diameter of about 0.8 to 2 mm, preferably about 1 to 1.8 mm, or well said support is formed essentially of extrudates whose smallest dimension is about 0.8 to 2 mm, preferably about 1 to 1.8 mm, i.e. the extrudates have was shaped using any extrusion technique known to those skilled in the art, such as for example a die with a diameter of about 0.8 to 2 mm, preferably about 1 to 1.8 mm.

L'alumine gamma éventuellement présente dans le support du catalyseur possède une surface spécifique d'environ 150 à 300 m2/g et de préférence d'environ 180 à 250 m2/g, et un volume poreux total généralement d'environ 0,4 à 0,8 cm3/g et de manière préférée d'environ 0,45 à 0,7 cm3/g.
L'alumine êta éventuellement présente dans le support du catalyseur possède une surface spécifique d'environ 400 à 600 m2/g et de préférence d'environ 420 à 550 m2/g, et un volume poreux total d'environ 0,3 à 0,5 cm3/g et de manière préférée d'environ 0,35 à 0,45 cm3/g.The gamma alumina possibly present in the support of the catalyst has a specific surface of approximately 150 to 300 m 2 / g and preferably of approximately 180 to 250 m 2 / g, and a total pore volume generally of approximately 0, 4 to 0.8 cm 3 / g and preferably about 0.45 to 0.7 cm 3 / g.
The alumina was optionally present in the catalyst support has a specific surface of approximately 400 to 600 m 2 / g and preferably of approximately 420 to 550 m 2 / g, and a total pore volume of approximately 0.3 at 0.5 cm 3 / g and preferably about 0.35 to 0.45 cm 3 / g.

Le métal du groupe VIII est choisi dans le groupe formé par le fer, le cobalt, le nickel, le ruthénium, le rhodium, le palladium, l'osmium, l'iridium et le platine, de préférence choisi dans le groupe formé par le platine, le palladium et le nickel. Dans le cas préféré où ledit métal est le platine ou le palladium, la teneur est d'environ 0,05 à 2 % poids et de manière préférée d'environ 0,1 à 1,5 % poids. Dans le cas préféré où ledit métal est le nickel, la teneur pondérale est d'environ 0,1 à 10 % poids et de manière préférée d'environ 0,2 à 6 % poids.The metal of group VIII is chosen from the group formed by iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably chosen in the group formed by platinum, palladium and nickel. In the preferred case where said metal is platinum or palladium, the content is about 0.05 to 2% by weight and so preferred about 0.1 to 1.5% by weight. In the preferred case where said metal is nickel, the weight content is from about 0.1 to 10% by weight and preferably from about 0.2 to 6% weight.

La préparation du catalyseur s'effectue généralement par mise en forme du support. Le dit support mis en forme subit peut éventuellement subir un traitement sous vapeur d'eau à haute température avant ou après le dépôt d'au moins un métal du groupe VIII. Une halogénation, de préférence une chloration, est ensuite effectuée. Il est également possible et préféré d'effectuer une étape d'activation sous hydrogène, avant ladite étape d'halogénation. Chaque étape du procédé de préparation du support selon l'invention est explicitée ci-après. The preparation of the catalyst is generally carried out by shaping the support. Says it support shaped suddenly can optionally undergo a treatment under steam at high temperature before or after the deposition of at least one group VIII metal. A halogenation, preferably chlorination, is then carried out. It is also possible and preferred to carry out an activation step under hydrogen, before said step halogenation. Each step of the process for preparing the support according to the invention is explained below.

Dans le cas où les deux types d'alumines (gamma et êta) sont présentes dans le support du catalyseur, ces deux types d'alumines sont de préférence mélangées et mises en forme ensemble, selon toute technique connue de l'homme du métier, par exemple par extrusion au travers d'une filière, par pastillage ou par dragéification. Mais il est aussi possible de mettre les deux types d'alumine en forme séparément, puis de procéder au mélange des deux alumines mises en forme. Dans tous les cas, la plus petite dimension de la forme géométrique décrite par le support après mise en forme est d'environ 0,8 à 2 mm, de préférence d'environ 1 à 1,8 mm, ce qui permet d'obtenir, lors de l'étape d'halogénation du support, une teneur en halogène suffisante pour une durée d'halogénation réduite.
Le support subit préférentiellement un traitement à haute température sous vapeur d'eau. Le traitement hydrothermal est réalisé généralement pendant 0,5 à 6 heures par exemple à une température d'environ 200 à 700°C sous flux de gaz par exemple l'air et/ou l'azote. Le gaz doit contenir de l'eau par exemple à des teneurs d'environ 0,2 % à 100 % en volume et de préférence d'environ 0,3 % à 20% en volume. L'activation de l'alumine par la vapeur d'eau permet d'obtenir des catalyseurs beaucoup plus acides et donc beaucoup plus actifs en isomérisation.In the case where the two types of aluminas (gamma and eta) are present in the catalyst support, these two types of aluminas are preferably mixed and shaped together, according to any technique known to those skilled in the art, for example by extrusion through a die, by pelleting or by coating. However, it is also possible to shape the two types of alumina separately, then to mix the two shaped aluminas. In all cases, the smallest dimension of the geometric shape described by the support after shaping is approximately 0.8 to 2 mm, preferably approximately 1 to 1.8 mm, which makes it possible to obtain , during the halogenation stage of the support, a sufficient halogen content for a reduced halogenation period.
The support preferably undergoes a treatment at high temperature under water vapor. The hydrothermal treatment is generally carried out for 0.5 to 6 hours, for example at a temperature of around 200 to 700 ° C. under a gas flow, for example air and / or nitrogen. The gas must contain water, for example at contents of about 0.2% to 100% by volume and preferably about 0.3% to 20% by volume. The activation of alumina by water vapor makes it possible to obtain much more acidic catalysts and therefore much more active in isomerization.

Au moins un métal hydrogénant du groupe VIII, choisi dans le groupe formé par le fer, le cobalt, le nickel, le ruthénium, le rhodium, le palladium, l'osmium, l'iridium et le platine, de préférence choisi dans le groupe formé par le platine, le palladium, et le nickel, est ensuite déposé sur le support par toute technique connue de l'homme du métier, par exemple par échange anionique sous forme d'acide hexachloroplatinique dans le cas du platine ou sous forme de chlorure dans le cas du palladium. Le traitement hydrothermal peut être réalisé après dépôt du métal sur le support.At least one hydrogenating metal from group VIII, chosen from the group formed by iron, the cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum, preferably chosen from the group formed by platinum, palladium, and nickel, is then deposited on the support by any technique known to those skilled in the art, by example by anion exchange in the form of hexachloroplatinic acid in the case of platinum or in the form of chloride in the case of palladium. Hydrothermal treatment can be made after depositing the metal on the support.

Le support comprenant le métal déposé peut alors éventuellement subir un traitement sous hydrogène ce qui permet d'obtenir une phase métallique active. La procédure de ce traitement sous hydrogène comprend par exemple une montée lente de la température sous courant d'hydrogène jusqu'à la température maximale de réduction qui est d'environ 300 à 700°C, et de préférence comprise entre 340 à 680°C, suivie d'un maintien de cette température, généralement pendant 1 à 6 heures, de préférence pendant 1,5 à 4,5 heures.The support comprising the deposited metal can then optionally undergo a treatment under hydrogen which makes it possible to obtain an active metallic phase. The procedure of this hydrogen treatment for example includes a slow rise in temperature under hydrogen flow up to the maximum reduction temperature which is around 300 to 700 ° C, and preferably between 340 to 680 ° C, followed by maintaining this temperature, generally for 1 to 6 hours, preferably for 1.5 to 4.5 hours.

L'étape d'halogénation peut être effectuée selon n'importe quelle technique connue de l'homme du métier. L'halogène, de préférence le chlore, est déposé préférentiellement à partir de n'importe quel composé carboné comprenant également des atomes d'halogène et connu pour réaliser une halogénation, de préférence dans des conditions que l'homme du métier jugera raisonnables tant au niveau du traitement des effluents, que de la durée de l'halogénation ou du coût. Pour cette raison l'utilisation du chlorure d'hydrogène est rarement retenue sans être cependant complètement exclue. L'halogénation, de préférence la chloration, de l'alumine est effectuée directement dans l'unité d'isomérisation avant l'injection de la charge à traiter, ou hors site : dans une unité séparée, prévue pour l'halogénation. L'halogénation peut être effectuée par tout agent carboné halogénant, de préférence chlorant, connu de l'homme du métier. De manière préférée, dans le cas où l'halogène est le chlore, on utilise habituellement le tétrachlorure de carbone ou le chloroforme.The halogenation step can be carried out according to any known technique of the skilled person. The halogen, preferably chlorine, is preferentially deposited at from any carbon compound also comprising halogen atoms and known to perform halogenation, preferably under conditions that those skilled in the art trade will deem reasonable both in terms of effluent treatment and the duration of halogenation or cost. For this reason the use of hydrogen chloride is rarely retained without however being completely excluded. Halogenation, preferably chlorination, alumina is carried out directly in the isomerization unit before injection of the load to be treated, or off site: in a separate unit, intended for halogenation. The halogenation can be carried out by any halogenating carbon agent, of preferably chlorinating agent, known to those skilled in the art. Preferably, in the case where halogen is chlorine, we usually use carbon tetrachloride or chloroform.

Dans le procédé de préparation du catalyseur, il est aussi possible de procéder au traitement d'halogénation préalablement au traitement de réduction sous hydrogène. Dans ce cas, le traitement de réduction sous hydrogène peut avoir lieu en dehors de l'unité (ex situ"), ce qui implique de prendre des précautions particulières pour le transport dudit catalyseur jusqu'à ladite unité, ou bien ledit traitement peut avoir lieu au sein de l'unité ("in-situ") juste avant l'utilisation dudit catalyseur.In the catalyst preparation process, it is also possible to carry out the halogenation treatment prior to reduction treatment under hydrogen. In in this case, the reduction treatment under hydrogen can take place outside the unit (e.g. situ "), which implies taking special precautions for the transport of said catalyst up to said unit, or else said treatment can take place within the unit ("in-situ") just before the use of said catalyst.

La présente invention concerne un procédé d'isomérisation d'une charge comprenant en majeure partie des paraffines normales contenant de 5 à 8 atomes de carbone par molécule, caractérisé en ce que la somme des teneurs en paraffines normales à 7 et à 8 atomes de carbone par molécule contenues dans la charge est comprise entre 2 et 90 % poids, de préférence entre 5 et 90 % poids, de manière plus préférée entre 20 et 90 % poids, et de façon très préférée entre 40 et 90 % poids par rapport à la charge, et en ce que ladite charge est traitée dans au moins une zone réactionnelle, contenant de préférence au moins un catalyseur en lit fixe, ledit catalyseur comprenant un support , au moins un halogène et au moins un métal du groupe VIII, la réaction étant effectuée à une température comprise entre 70 et 95°C la charge à traiter contenant préférentiellement au moins un composé halogéné, de manière plus préférée un composé chloré, dont la teneur pondérale dans ladite charge est comprise entre 50 et 2000 ppm, et le plus souvent entre 50 et 300 ppm, par exemple du perchloréthylène C2Cl4,The present invention relates to a process for the isomerization of a charge mainly comprising normal paraffins containing from 5 to 8 carbon atoms per molecule, characterized in that the sum of the contents of normal paraffins at 7 and 8 carbon atoms per molecule contained in the charge is between 2 and 90% by weight, preferably between 5 and 90% by weight, more preferably between 20 and 90% by weight, and very preferably between 40 and 90% by weight relative to the feed, and in that said feed is treated in at least one reaction zone, preferably containing at least one fixed bed catalyst, said catalyst comprising a support, at least one halogen and at least one group VIII metal, the reaction being carried out at a temperature of between 70 and 95 ° C. the feed to be treated preferably containing at least one halogenated compound, more preferably a chlorinated compound, the pon content of which derale in said charge is between 50 and 2000 ppm, and most often between 50 and 300 ppm, for example perchlorethylene C 2 Cl 4 ,

Deux modes de réalisation de l'invention peuvent être considérés, il seront choisis en fonction de la valeur de l'excès d'hydrogène par rapport à la quantité d'hydrogène consommé par les réactions d'hydrogénation, d'ouverture des cycles naphténiques et de craquage des paraffines. Ceci peut aussi s'exprimer par le rapport R du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures de l'effluent sortant du réacteur.Two embodiments of the invention can be considered, they will be chosen in function of the amount of excess hydrogen relative to the amount of hydrogen consumed by hydrogenation reactions, the opening of naphthenic cycles and paraffin cracking. This can also be expressed by the ratio R of the number of moles of hydrogen on the number of moles of hydrocarbons in the effluent leaving the reactor.

Dans le premier mode de réalisation de l'invention on utilise un faible excès d'hydrogène, de façon à ce que le rapport R du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé sur la base de la composition de l'effluent sortant du réacteur soit comprise entre 0,06 et 0,3, de préférence 0,06 et 0,2. Dans ce cas il n'est pas nécessaire de recycler l'hydrogène non consommé vers l'entrée du réacteur. On opère alors à «hydrogène perdu ».In the first embodiment of the invention, a small excess of hydrogen is used, so that the ratio R of the number of moles of hydrogen to the number of moles of hydrocarbons calculated on the basis of the composition of the effluent leaving the reactor either between 0.06 and 0.3, preferably 0.06 and 0.2. In this case it is not necessary to recycle the hydrogen not consumed towards the inlet of the reactor. We then operate at "Lost hydrogen".

Dans le second mode de réalisation de l'invention, on utilise un large excès d'hydrogène. Le rapport R du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé sur la base de la composition de l'effluent en sortie de réacteur est alors comprise entre 0,3 et 10, de préférence entre 0,3 et 5, et d'une manière encore plus préférée entre 0,5 et 3. Dans ce cas l'excès d'hydrogène est recyclé vers l'entrée du réacteur par exemple au moyen d'un ballon de séparation gaz-liquide et d'un compresseur de recyclage. Selon ce mode de l'invention il est possible d'ajuster la pression partielle d'hydrogène dans une plage plus étendue que dans le premier mode de réalisation.In the second embodiment of the invention, a large excess of hydrogen is used. The ratio R of the number of moles of hydrogen to the number of moles of hydrocarbons calculated on the basis of the composition of the effluent leaving the reactor is then understood between 0.3 and 10, preferably between 0.3 and 5, and even more preferably between 0.5 and 3. In this case the excess hydrogen is recycled to the inlet of the reactor for example by means of a gas-liquid separation tank and a recycling compressor. according to this mode of the invention it is possible to adjust the partial pressure of hydrogen in a wider range than in the first embodiment.

Les gammes préférées de conditions opératoires données ci-après s'appliquent aux deux modes de réalisation de l'invention.
La vitesse volumique horaire (PPH) définie comme le débit massique de charge à traiter par masse de catalyseur et par heure est d'environ de 0,2 à 10 kg de charge par kg de catalyseur et par heure (0,2 à 10 h-1), de préférence d'environ 0,3 à 5 kg de charge par kg de catalyseur et par heure (0.3 à 5 h-1) et d'une manière encore plus préférée entre 0,5 et 2 kg de charge par kg de catalyseur et par heure (0,5 à 2 h-1).
La pression du réacteur est d'environ 0,1 à 10 MPa relatifs, de préférence d'environ 0,5 à 8 MPa relatifs, de manière plus préféré entre 2 et 5 MPa.
La température du réacteur est comprise entre 70 et 95°C.The preferred ranges of operating conditions given below apply to the two embodiments of the invention.
The hourly volume velocity (PPH) defined as the mass flow rate of feed to be treated per mass of catalyst and per hour is approximately 0.2 to 10 kg of feed per kg of catalyst and per hour (0.2 to 10 h -1 ), preferably around 0.3 to 5 kg of feed per kg of catalyst per hour (0.3 to 5 h -1 ) and even more preferably between 0.5 and 2 kg of feed per kg of catalyst per hour (0.5 to 2 h -1 ).
The reactor pressure is about 0.1 to 10 MPa relative, preferably about 0.5 to 8 MPa relative, more preferably between 2 and 5 MPa.
The reactor temperature is between 70 and 95 ° C.

L'utilisation d'un catalyseur comprenant un support, au moins un halogène et au moins un métal du groupe VIII, dans les conditions opératoires indiquées ci-devant conduit d'une façon surprenante à l'obtention de niveaux de conversion élevés des n-paraffines C5-C8, et plus particulièrement du n-heptane tout en conservant des rendements élevés en isomérats, c'est-à-dire en essence légère essentiellement constituée d'hydrocarbures contenant de 5 à 8 atomes de carbone. L'utilisation de ce catalyseur permet donc d'obtenir un faible taux de craquage.The use of a catalyst comprising a support, at least one halogen and at least one metal of group VIII, under the operating conditions indicated above leads to a surprisingly in obtaining high levels of conversion of C5-C8 n-paraffins, and more particularly n-heptane while retaining high yields of isomers, that is to say in light gasoline essentially consisting of hydrocarbons containing 5 to 8 carbon atoms. The use of this catalyst therefore makes it possible to obtain a low cracking rate.

Le procédé selon l'invention peut traiter tous types de charges comprenant en majeure partie des paraffines normales contenant de 5 à 8 atomes de carbone, des naphtènes, des aromatiques (en quantités habituellement inférieure à 10% poids). Plus particulièrement, le procédé selon l'invention permet de traiter des coupes paraffiniques dont la chaíne contient de 5 à 8 atomes de carbone, et dans lesquelles la somme des teneurs en paraffines normales à 7 et à 8 atomes de carbone par molécule comprises dans la coupe est comprise entre 2 à 90 % poids, de façon préférée entre 5 et 90 % poids, de manière plus préférée entre 20 et 90% poids et de façon très préférée de 40 à 90 % poids.The method according to the invention can treat all types of charges comprising in major part of normal paraffins containing from 5 to 8 carbon atoms, naphthenes, aromatic (in amounts usually less than 10% by weight). More specifically, the process according to the invention makes it possible to treat paraffinic cuts including the chain contains 5 to 8 carbon atoms, and in which the sum of the paraffin contents normal to 7 and 8 carbon atoms per molecule included in the section is included between 2 to 90% by weight, preferably between 5 and 90% by weight, more preferably between 20 and 90% by weight and very preferably from 40 to 90% by weight.

On veillera de préférence à ce que les charges du procédé selon l'invention soient exemptes d'eau, d'oxygène, de soufre et d'une façon plus générale de tous les composés connus comme étant des poisons ou des inhibiteurs des catalyseurs à base d'alumine halogénée.It will preferably be ensured that the charges of the process according to the invention are free of water, oxygen, sulfur and more generally all compounds known to be poisons or inhibitors of alumina catalysts halogenated.

Les exemples suivants illustrent l'invention sans en limiter la portée.The following examples illustrate the invention without limiting its scope.

EXEMPLES :EXAMPLES:

On utilise un réacteur d'un volume de 200 ml, alimenté en mode d'écoulement ascendant des fluides par le mélange constitué par la charge à traiter et par l'hydrogène. L'effluent sortant du réacteur est refroidi puis analysé par chromatographie en phase vapeur.A reactor with a volume of 200 ml is used, fed in upflow mode fluids by the mixture constituted by the charge to be treated and by the hydrogen. The effluent leaving the reactor is cooled and then analyzed by vapor phase chromatography.

Exemple 1 (conforme à l'invention) Example 1 (according to the invention)

Pour cet exemple on utilise un catalyseur industriel à base d'alumine chloré commercialisé par la société Procatalyse sous la référence IS 612A.For this example, an industrial catalyst based on chlorinated alumina sold is used. by the company Procatalyse under the reference IS 612A.

On utilise par ailleurs un réacteur d'un volume de 200 ml, alimenté en mode d'écoulement ascendant des fluides par le mélange constitué par la charge à traiter et par l'hydrogène. L'effluent sortant du réacteur est refroidi puis analysé par chromatographie en phase vapeur.A reactor with a volume of 200 ml is also used, fed in flow mode ascending of fluids by the mixture constituted by the load to be treated and by hydrogen. The effluent leaving the reactor is cooled and then analyzed by phase chromatography steam.

Les conditions opératoires sont les suivantes : Le réacteur est alimenté en une charge comprenant des hydrocarbures contenant de 5 à 7 atomes de carbone et 800 ppm en poids de perchloréthylène (C2Cl4) au débit 87 g/h, la masse du catalyseur étant de 86 g, la PPH est de 1,01 h-1. Le débit d'hydrogène est de 4,5 10-9 l/h. La pression totale est de 3 MPa relatifs. Deux isomérisations à des températures différentes sont effectuées sur la même charge, l'isomérisation 1 est effectuée à une température de 105 °C, le rapport R1 du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé en sortie de réacteur est égal à 0,14, l'isomérisation 2 est effectuée à 115 °C et le rapport R2 du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé en sortie de réacteur est égal à 0,11.The operating conditions are as follows: The reactor is supplied with a feed comprising hydrocarbons containing from 5 to 7 carbon atoms and 800 ppm by weight of perchlorethylene (C 2 Cl 4 ) at a flow rate of 87 g / h, the mass of the catalyst being of 86 g, the PPH is 1.01 h -1 . The hydrogen flow rate is 4.5 10 -9 l / h. The total pressure is 3 MPa relative. Two isomerizations at different temperatures are carried out on the same charge, isomerization 1 is carried out at a temperature of 105 ° C., the ratio R1 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 0.14, isomerization 2 is carried out at 115 ° C. and the ratio R2 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 0.11.

Les résultats obtenus sont présentés dans le tableau 1. Composés Charge (% en poids) Après isomérisation 1 (% en poids) Après isomérisation2 (% en poids) C2-C4 0,74 5,19 7,15 iC5 4,19 6,72 7,62 nC5 10,53 7,67 7,5 cyclopentane 0,28 0,27 0,28 iC6 4,01 4,32 4,73 nC6 1,06 0,82 0,88 cyclohexane 1,4 3,04 2,6 méthylcyclopentane 1,01 1,66 1,62 benzène 0,01 0 0 nC7 65,7 20,00 17,35 iC7 11,7 50,31 50,27 Isomérisation 1 Isomérisation 2 conversion nC5 29% 27% conversion nC6 17% 22,60% conversion nC7 73,6 % 69,60% rendement C5+ 93,5 % 95,50% The results obtained are presented in Table 1. compounds Load (% by weight) After isomerization 1 (% by weight) After isomerization2 (% by weight) C2-C4 0.74 5.19 7.15 iC5 4.19 6.72 7.62 nC5 10.53 7.67 7.5 cyclopentane 0.28 0.27 0.28 IC6 4.01 4.32 4.73 nC6 1.06 0.82 0.88 cyclohexane 1.4 3.04 2.6 methylcyclopentane 1.01 1.66 1.62 benzene 0.01 0 0 nC7 65.7 20.00 17.35 IC7 11.7 50.31 50.27 Isomerization 1 Isomerization 2 nC5 conversion 29% 27% nC6 conversion 17% 22.60% nC7 conversion 73.6% 69.60% C5 + efficiency 93.5% 95.50%

Les résultats du tableau 1 montrent que l'on obtient des niveaux de conversion du n-heptane de l'ordre de 70%, tout en ne produisant que 4,45% en poids de produits légers pour une isomérisation effectuée à 105 °C et 6,41% en poids pour une isomérisation effectuée à 115 °C. Par produits légers, on entend une fraction essentiellement constituée d'hydrocarbures contenant de 2 à 4 atomes de carbone.The results of Table 1 show that levels of conversion of n-heptane are obtained. of the order of 70%, while producing only 4.45% by weight of light products for isomerization carried out at 105 ° C and 6.41% by weight for isomerization performed at 115 ° C. By light products is meant a fraction essentially constituted of hydrocarbons containing from 2 to 4 carbon atoms.

Ces résultats sont d'un grand intérêt du point de vue industriel car les conditions opératoires sont très douces : les températures étant de 105 °C et 115 °C.These results are of great interest from an industrial point of view because the conditions The operating procedures are very gentle: the temperatures being 105 ° C and 115 ° C.

Exemple 2Example 2

Dans cet exemple on utilise le même catalyseur et le même réacteur que dans l'exemple 1.In this example, the same catalyst and the same reactor are used as in Example 1.

Le réacteur est alimenté en une charge comprenant des hydrocarbures contenant de 5 7 atomes de carbone et 800 ppm poids de perchloréthylène (C2C14) au débit 84 g/h, la masse du catalyseur étant de 84 g, la PPH est de 1 h-1. Le débit d'hydrogène est de 60 10-9 l/h. La pression totale est de 3 MPa relatifs.
Deux isomérisations à des températures différentes sont effectuées sur la même charge, l'isomérisation 3 est effectuée à une température de 115 °C, le rapport R3 du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé en sortie de réacteur est égal à 2,67 et l'isomérisation 4 est effectuée à 130 °C, le rapport R4 du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé en sortie de réacteur est égal à 2,56.The reactor is supplied with a feed comprising hydrocarbons containing 5 to 7 carbon atoms and 800 ppm by weight of perchlorethylene (C2C14) at a flow rate of 84 g / h, the mass of the catalyst being 84 g, the PPH is 1 h-1 . The hydrogen flow rate is 60 10 -9 l / h. The total pressure is 3 MPa relative.
Two isomerizations at different temperatures are carried out on the same charge, isomerization 3 is carried out at a temperature of 115 ° C., the ratio R3 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 2.67 and isomerization 4 is carried out at 130 ° C., the ratio R4 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the outlet of the reactor is equal to 2.56.

La différence principale par rapport à l'exemple 1, est que cet exemple 2 correspond à un procédé d'isomérisation dans lequel on utilise un large excès d'hydrogène par rapport à la charge à convertir.
La composition de la charge et les résultats obtenus sont illustrés au moyen du tableau 2. Composés Charge (% en poids) Après isomérisation 3 (% en poids) Après isomérisation4 (% en poids) C2-C4 0,87 5,99 9,51 iC5 9,95 11,73 12,5 nC5 7,79 6,33 6,18 cyclopentane 0,62 0,62 0,62 iC6 9,50 10,40 11,01 nC6 2,97 2,07 2,02 cyclohexane 5,10 3,79 3,19 méthylcyclopentane 2,32 2,47 2,67 benzène 0,17 0 0 nC7 55,41 13,63 9,15 iC7 5,30 42,97 43,15 Isomérisation 1 Isomérisation 2 conversion nC5 18,8% 20,7% conversion nC6 30,3% 32% conversion nC7 75,4% 83,5% rendement C5+ 94,8% 91,3% The main difference compared to example 1, is that this example 2 corresponds to an isomerization process in which a large excess of hydrogen is used with respect to the feed to be converted.
The composition of the charge and the results obtained are illustrated by means of Table 2. compounds Load (% by weight) After isomerization 3 (% by weight) After isomerization4 (% by weight) C2-C4 0.87 5.99 9.51 iC5 9.95 11,73 12.5 nC5 7.79 6.33 6.18 cyclopentane 0.62 0.62 0.62 IC6 9.50 10.40 11,01 nC6 2.97 2.07 2.02 cyclohexane 5.10 3.79 3.19 methylcyclopentane 2.32 2.47 2.67 benzene 0.17 0 0 nC7 55.41 13.63 9.15 IC7 5.30 42.97 43,15 Isomerization 1 Isomerization 2 nC5 conversion 18.8% 20.7% nC6 conversion 30.3% 32% nC7 conversion 75.4% 83.5% C5 + efficiency 94.8% 91.3%

Comme dans l'exemple 1, des taux de conversion élevés du n-heptane en iso-heptanes sont obtenus, dans des conditions opératoires où la quantité de produits légers formés par craquage reste faible. Les résultats du tableau 2 montrent que l'on obtient des taux de conversion du n-heptane de l'ordre de 75 à 80 %, tout en ne produisant que 5,1 % en poids de produits légers pour une isomérisation effectuée à 115 °C et 8,7 % en poids pour une isomérisation effectuée à 130 °C .As in Example 1, high conversion rates of n-heptane to iso-heptanes are obtained, under operating conditions where the quantity of light products formed by cracking remains low. The results in Table 2 show that rates of conversion of n-heptane of the order of 75 to 80%, while producing only 5.1% by weight light products for isomerization carried out at 115 ° C and 8.7% by weight for a isomerization carried out at 130 ° C.

Le tableau 2 illustre également le fait que 130 °C est une température sensiblement peu éloignée de la température maximale compatible avec l'obtention de rendements élevés en isomérats, en particulier si l'on estime qu'un taux de craquage en produits légers de 10 % est la limite supérieure acceptable. En effet, à 130°C on obtient déjà 8,7 % de produits légers formés par craquage, donc un rendement en paraffines ramifiées contenant de 5 à 7 atomes de carbone de 91,3 %. Table 2 also illustrates the fact that 130 ° C is an appreciably low temperature. away from the maximum temperature compatible with obtaining high yields in isomers, in particular if it is estimated that a cracking rate in light products of 10% is the upper acceptable limit. In fact, at 130 ° C, 8.7% of products are already obtained light formed by cracking, therefore a yield of branched paraffins containing from 5 to 7 91.3% carbon atoms.

Exemple 3Example 3

Le catalyseur utilisé dans l'exemple 3 est fabriqué comme suit : de l'alumine gamma est mise en forme par extrusion au travers d'une filière de diamètre 1,2 mm. Le solide ainsi mis en forme est traité à 500°C par de l'air contenant 3% en volume de vapeur d'eau. On dépose sur ladite alumine mise en forme 0,2 % de platine par échange ionique avec de l'acide hexachloroplatinique en présence d'HCl comme agent compétiteur. Le solide obtenu est réduit sous hydrogène à 400°C.
On procède ensuite à la chloration du solide obtenu, à une température de 280°C, par injection de tétrachlorure de carbone sous courant d'azote.The catalyst used in Example 3 is manufactured as follows: gamma alumina is formed by extrusion through a die with a diameter of 1.2 mm. The solid thus formed is treated at 500 ° C with air containing 3% by volume of water vapor. 0.2% of platinum-shaped alumina is deposited on said alumina by ion exchange with hexachloroplatinic acid in the presence of HCl as a competing agent. The solid obtained is reduced under hydrogen at 400 ° C.
The solid obtained is then chlorinated, at a temperature of 280 ° C., by injection of carbon tetrachloride under a stream of nitrogen.

La charge à traiter est constituée d'environ 10 % en poids de paraffines normales à 5 atomes de carbone, 10 % en poids de paraffines normales à 6 atomes de carbone, 65 % en poids de paraffines normales à 7 atomes de carbone et 8 % en poids de naphtènes à 6 atomes de carbone. Ladite charge contenant 100 ppm de tétrachlorure de carbone (CCl4) exprimé en poids de chlore pour maintenir la teneur en chlore du catalyseur utilisé.The load to be treated consists of approximately 10% by weight of normal paraffins with 5 carbon atoms, 10% by weight of normal paraffins with 6 carbon atoms, 65% by weight of normal paraffins with 7 carbon atoms and 8% by weight of naphthenes containing 6 carbon atoms. Said feed containing 100 ppm of carbon tetrachloride (CCl 4 ) expressed by weight of chlorine to maintain the chlorine content of the catalyst used.

Les conditions opératoires de l'isomérisation sont les suivantes : la température du réacteur est 110°C, la pression totale de 3 MPa relatifs, la PPH de 1 h-1et le rapport R5 du nombre de moles d'hydrogène sur le nombre de moles d'hydrocarbures calculé en sortie de réacteur est égal à 0,47.The isomerization operating conditions are as follows: the reactor temperature is 110 ° C., the total pressure of 3 relative MPa, the PPH of 1 h -1 and the ratio R5 of the number of moles of hydrogen to the number of moles of hydrocarbons calculated at the reactor outlet is equal to 0.47.

Les performances obtenues après 24 heures de fonctionnement sont les suivantes : on obtient des taux de conversion du n-heptane de 73,5 tout en ne produisant que 4,6 % en poids de produits légersThe performances obtained after 24 hours of operation are as follows: obtains 73.5 n-heptane conversion rates while producing only 4.6% weight of light products

Claims (15)

  1. A process for isomerising a feed comprising normal paraffins containing 5 to 8 carbon atoms per molecule as a major portion in the presence of hydrogen, wherein the sum of the amounts of normal paraffins containing 7 and 8 carbon atoms per molecule contained in the feed is in the range 2% to 90% by weight with respect to the feed, and in that said feed is treated in at least one reaction zone, containing at least one catalyst in a fixed bed, said catalyst comprising a support, at least one halogen and at least one group VIII metal, characterized in that the reaction is carried out at a temperature in the range 70°C to 95°C.
  2. An isomerisation process according to claim 1, wherein the sum of the amounts of normal paraffins containing 7 and 8 carbon atoms per molecule contained in the feed is in the range 5% to 90% by weight
  3. An isomerisation process according to claim 1, wherein the sum of the amounts of normal paraffins containing 7 and 8 carbon atoms per molecule contained in the feed is in the range 20% to 90% by weight.
  4. An isomerisation process according to claim 1, wherein the sum of the amounts of normal paraffins containing 7 and 8 carbon atoms per molecule contained in the feed is in the range 40% to 90% by weight.
  5. An isomerisation process according to any one of claims 1 to 4, characterized in that a treatment of the support at a temperature of 200 to 700°C in steam is carried out before or after depositing at least one metal.
  6. An isomerisation process according to any one of claims 1 to 5, wherein the support is treated for 0.5 to 6 hours at a temperature of 200°C to 700°C, in a stream of a gas containing water in amounts of 0.2% to 100% by volume.
  7. A process according to any one of claims 1 to 6, wherein the support is alumina based, and this alumina comprises between 50 and 95 % of êta alumina the complement being gamma alumina.
  8. A process according to any one of claims 1 to 7, wherein the feed to be treated contains at least one halogenated compound in an amount in said feed in the range 50 to 2000 ppm by weight.
  9. An isomerisation process according to any one of claims 1 to 8, characterized in that the halogen contained in the support is chlorine.
  10. An isomerisation process according to any one of claims 1 to 9, characterized in that the support contains a halogen in amounts in the range 0.1% to 15% by weight.
  11. An isomerisation process according to any one of claims 1 to 10, characterized in that the total reaction pressure is 0.1 to 10 MPa relative, the hourly space velocity being 0.2 to 10 h-1.
  12. An isomerisation process according to any one of claims 1 to 11, characterized in that the reaction is carried out in the presence of an excess of hydrogen such that the ratio R of the number of moles of hydrogen over the number of moles of hydrocarbons calculated on the basis of the composition of the effluent leaving the reactor is in the range 0.06 to 0.3.
  13. An isomerisation process according to any one of claims 1 to 11, characterized in that the reaction is carried out in the presence of an excess of hydrogen such that the ratio R of the number of moles of hydrogen over the number of moles of hydrocarbons calculated on the basis of the composition of the effluent leaving the reactor is in the range 0.3 to 10.
  14. An isomerisation process according to any one of claims 1 to 13, characterized in that the catalyst undergoes treatment in hydrogen before depositing at least one halogen.
  15. An isomerisation process according to claim 14, characterized in that the treatment under hydrogen comprises a slow rise in temperature in a stream of hydrogen up to the maximum reduction temperature which is 300°C to 700°C, followed by maintaining that temperature, generally for 1 to 6 hours.
EP98402869A 1997-11-25 1998-11-19 Process for isomerisation of C5-C8 paraffinic fractions rich in paraffins with more than seven carbon atoms Expired - Lifetime EP0922747B1 (en)

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FR9714892 1997-11-25

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FR2771417A1 (en) 1999-05-28
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KR19990045556A (en) 1999-06-25
EP0922747A1 (en) 1999-06-16
KR100567996B1 (en) 2006-07-11
CA2252065A1 (en) 1999-05-25
FR2771417B1 (en) 1999-12-31
JPH11236577A (en) 1999-08-31
US20020002319A1 (en) 2002-01-03
DE69819286T2 (en) 2004-05-13

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