MXPA00008210A - Process for the production of oils with high viscosity index - Google Patents

Abstract

The process enables the recovery of oil fractions graded according to their viscosity indices by direct treatmentof petroleum fractions. Middle distillates can also be recovered. A process for the production of oils of high viscosity index (VI) from a charge consisting of compounds of boiling points higher than 300 degrees C., comprises (a) reaction of the charge, or a mixture of charge with a re-cycled fraction from stage (c), with hydrogen in the presence of a catalyst comprising an amorphous non-zeolitic matrix and a group VIII metal or metal compound and/or a group VIB metal;(b) fractionation of the effluent from (a) to separate off a residue of oils mainly containing constituents of VI higher than that of the charge;and (c) fractionation of the oil residues from (b) by thermal diffusion, the oils being separated according to their viscosity.

Description

PROCEDURE FOR THE PRODUCTION OF OILS WHICH HAVE A HIGH VISCOSITY INDEX The subject of the present invention is a process for obtaining oils having high viscosity indexes, and more particularly viscosity indexes greater than about 100, from a filler containing constituents with boiling points above 300 ° C. The process is a chain of operations, which allow the recovery of an oily residue that is partly fractionated by thermal diffusion, in different oils of different compositions and viscosity indexes.

The use of functional motors requires oils of increasingly high viscosity indexes.

The specifications on the indexes are currently between 95 and 100.

WO 97/18278 describes a process for producing dewaxed lubricating oils, comprising at least one zone of hydro fractionation, at least one dewaxing zone and REF. 122339 at least one hydroparaffin area. The hydrocarbon feedstock comprises first vacuum distillation gas oils, refined deasphalted oils or a mixture of two of these cuts. Fractional loads may also be added to the initial charge but in an amount not exceeding 20% due to its content in high aromatics and its content in light hydrogen.

US Pat. No. 4,975,177 discloses a process in three successive steps, of producing lubricants with a viscosity index of at least 130 and a slip point of less than 5 ° F, (-15 ° C) which comprises a dewaxing step starting from an oil filler to form a paraffin-rich filler containing at least 50% by mass of paraffin and having a boiling point above 650 ° F (343 ° C), a catalytic dewaxing stage by isomerization of the effluent obtained in the step a), at high pressure, in the presence of hydrogen and of a catalyst containing a beta zeolite and a hydro dehydrogenating function, in view of isomerizing the n-paraffins into iso-paraffins, as well as a selective dewaxing step, in the presence of of a zeolite-based catalyst having a tensile index of at least 8.

The presence of hydrogen in the second stage allows maintaining the activity of the catalyst and favoring the different stages of the isomerization mechanism. Isoperization then involves the hydrogenation and dehydrogenation of the paraffined filler.

The patent FR 600 669 of the applicant describes a hydro-fractionation process in three successive stages intended for the production of middle distillates (gasoline, kerosene and gas oil), which allows to collect fractions according to their boiling points. Thus, the fractions of boiling points lower than 375 ° C are recovered and those of boiling points higher than 375 ° C, are recycled. Or, the present application is based on the recovery of oily fractions according to their viscosity indexes. On the other hand, it makes it possible to recover, not only middle distillates but also a column bottom product containing essentially oils of different composition and viscosity indexes.

The object of the invention is the production of oils with high viscosity indexes, preferably greater than about 100, and even more preferably greater than about 140, by direct treatment of oil fractions. One of the advantages of the invention is the obtaining of oils of different compositions. Thus, the refiner has the decision between recovering the oils or recycling them, according to the limit viscosity index that has been set.

The invention more particularly concerns a process for the production of oils having a high viscosity index, and is applied to a filler which contains constituents with boiling points higher than 300 ° C.

The fillers used in the context of the present invention are petroleum fractions of boiling points higher than 300 ° C, usually comprised between 300 and 650 eference between approximately 350 and 550 ° C. These charges are of different origins. By way of non-limiting example, the charges mentioned come either from crude oil distillates or effluents from • conversion units such as, for example, fluidized bed catalytic fractionation units, hydro fractionation units or boiling bed hydro treatment.

These charges mainly contain aromatic, naphthenic and paraffinic compounds. They are characterized by defined kinematic viscosities, according to standard standards at 40 and 100 ° C. The kinematic viscosity at 40 ° C is usually between about 40 and 500 square millimeters per second (puir / s), frequently between about 40 and 300 mpr / s and the kinematic viscosity at 100 ° C, is generally between about 2 and 40 mpr / s, frequently between approximately 5 and 15 mrtr / s at 15 ° C. the charges have a density usually between about 0.89 and 0.98, frequently between about 0.91 and 0.97 at 15 ° C.

The process according to the invention is a process for producing oils having a high viscosity index, from a filler containing constituents of boiling points greater than about 300 ° C. It comprises a step a) in which hydrogen is reacted with the filler or with a mixture of the filler with at least a fraction of a recycle stream from step ©, in the presence of a catalyst comprising at least one amorphous matrix not zeolitic and at least one metal or metal compound of group VIII of the periodic classification of the elements and / or at least one metal of group VIB, a step b) in which at least a part of the effluent obtained in the step is fractionated a) so as to separate at least one residue of oils containing mostly constituents having viscosity indices higher than those of the filler, and a step c) in which at least a part of the fraction is fractionated by thermal diffusion. oil residue obtained in step b) in fractions of oils having high viscosity indexes. The mentioned procedure allows to separate the oils according to their viscosity index.

In step a), the load is converted to at least one effluent containing mostly kerosene, gasoline, diesel and oils.

The catalyst of the first stage may be in the form of beads, but is more frequently in the extruded form. The hydro-dehydrogenating function of said catalyst is ensured by the metal or metal compound selected in the group formed by the metals of group VIII of the periodic classification of the elements (nickel and cobalt in particular), and the metals of group VIB (molybdenum and tungsten particularly). It is also possible to associate at least one metal of group VIII (nickel and / or cobalt) with a metal of group VIB (molybdenum and / or tungsten).

The total concentration of the elements of groups VIII and VIB is expressed by their concentration in metal oxides. Thus, the concentration of the metal oxides of group VIII is usually between about 0.5 and 10 by mass and preferably between about 1 and 7% by mass. The concentration of the metal oxides of group VIB is usually between about 1 and 30 e in mass, and preferably between about 5 and 20 mass%. The total concentration of metal oxides of groups VIB and VIII is usually between about 5 and 40% by mass, and more often between about 7 and 30% by mass.

The mass ratio expressed in metal oxides between metal (or metals) of group VI on metal (or metals) of group VIII is generally about 20 to 1 and more frequently about 10 to 2.

The catalyst matrix of step a) is usually selected from the group consisting of aluminum, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals. Preferably, an alumina matrix is used? or? The matrix may also contain oxides selected from the group consisting of boron oxide, zirconium, titanium oxide and phosphoric anhydride. Frequently, the matrix is doped with phosphorus and eventually boron. The presence of the phosphorus in the catalyst makes it possible, on the one hand, to facilitate the preparation, in particular, of the impregnation of the nickel and molybdenum solutions, and on the other hand, to improve the acidity of the hydrogenation activity of the catalyst. The concentration in phosphoric anhydride P205 is usually less than about 20% in loop frequently less than about 10% and even more preferably less than about 1% by mass. The concentration in boron trioxide B; 03 is usually less than about 10% by mass. ' The hydrogen used in step a) of the process according to the invention serves essentially to hydrogenate the aromatic compounds contained in the filler.

The catalyst of step a) favors hydrogenation in relation to fractionation. It allows the opening of naphthenic cycles and the hydrogenation of aromatic compounds, in view of reducing the content of condensed polycyclic aromatic hydrocarbons. This reduction is translated by a decrease in the density of the effluent, as well as an increase in its content in paraffinic carbons and its viscosity index. In addition, most of the nitrogen products contained in the cargo are likewise processed. The catalyst of step a) enables the transformation of the sulfur compounds to hydrogen sulphide and nitrogen compounds in the form of ammonia to be promoted. The conversion of the load remains limited. Frequently, it remains less than or equal to about 50% by mass, in step a) of the process of the invention.

The effluent obtained in stage a) can be fractionated in at least one separator, in at least one gaseous effluent and in at least one liquid effluent. The gaseous effluent contains mainly hydrogen sulphide, ammonia and light hydrocarbons of 1 to 4 carbon atoms. Frequently, the separation requires a high pressure separator, which allows to eliminate the gaseous effluent that is evacuated. The light hydrocarbons that are recovered can be used in the fuel-gas network.

Step a) can be followed by a step d) of hydro fractionation, which brings into contact at least a part of the total effluent obtained in stage a) or a part of the liquid effluent obtained after fractionation, with hydrogen, in the presence of of a catalyst comprising at least one zeolite, at least one matrix, and at least one metal or metal compound of group VIII of the periodic classification of the elements and / or at least one metal of group VIB, the said metal having a hydrodehydrogenating function. This step d) makes it possible to improve the viscosity index of the oil residue in relation to that obtained in the absence of step d). The Stage d) is carried out when the refiner wishes to obtain very high viscosity indexes.

A fractionation can be contemplated on the effluent from step d). The separation process is identical to that performed on the effluent obtained in stage a). The effluent obtained in step d) can also be fractionated in at least one gaseous effluent and at least one liquid effluent. In a general manner, the fractionation can be effected at the exit of stage a), and / or at the exit of stage d). Preferably, the fractionation takes place at the output of step d) or at the output of stage a) when step d) is not carried out.

The zeolite of the catalyst of step d) is frequently an acid zeolite HY characterized by the following specifications: a molar ratio SiO; / Alc0 usually comprised between about 8 and 70 and preferably between about 12 and 40; a sodium content generally less than about 0.15% by mass, determined on the zeolite calcined at 1100 ° C; an observed crystalline parameter a, of the elemental mesh usually comprised between approximately 24.55. 10"'" meters (m) and 24.24. 10"iL, preferably between approximately 24.38, 10 and 14.26, 10 ~ l, m, a recovery capacity in sodium ions, expressed in grams (g) of sodium per 100 g of modified zeolite, neutralized then calcined , generally greater than about 0.85, a specific surface area determined by the BET method usually greater than about 400 itr / g (square meters per gram) and preferably greater than about 550 pr / g; a water vapor adsorption capacity at 25 ° C for a partial pressure of 2.6 torrs (ie 346.63 Pa), generally greater than about 6% by mass, a porous distribution • usually comprising between about 1 and 20% preferably between about 3 and 15% of the contained porous volume in pores of diameter located between approximately 20.10"10 m, the rest of the pore volume that is contained in the pores of diameter less than 20.10" 1 m.

The zeolite can possibly be doped by metal elements such as, for example, metals of the rare earth family, particularly lanthanum and cerium, or noble or non-noble metals of group VIII of the periodic classification of the elements, such as platinum, palladium, ruthenium, rhodium, iridium, iron and other metals such as manganese, zinc, magnesium.

The content weighed in zeolite is usually between approximately 2 and 80% and preferably between approximately 3 and 50% in relation to the final catalyst used in step d).

The catalyst matrix of step d) is a support selected from the group consisting of alumina, silica, silica alumina, boron alumina oxide, magnesia, silica-magnesia, zirconium, titanium oxide , the clay, these compounds that are used alone or in mixtures. Preferably, an alumina support is used.

The hydrodehydrogenating function is ensured by a combination of metals of groups VIB (molybdenum and / or tungsten, particularly) and VIII (cobalt and / or nickel, particularly) of the periodic classification of the elements. The catalyst may advantageously contain phosphorus, for the reasons mentioned above at the catalyst level of step a). The total concentration of metal oxides of the groups VIB and VIII is usually between about 1 and 40% by mass and preferably between about 3 and 30 I by mass. The basic ratio expressed in metal oxides, between metal (or metals) of group VI on metal (or metals) of group VIII is generally between about 10 and 1.25 and preferably between about 10 and 2. The concentration of oxides of phosphorus is usually less than about 15% by mass and preferably less than about 10% by mass.

The catalyst of step d) based on zeolite is more active than the catalyst of step a). Thus, the conversion rate of step d) is higher than that of the first stage. The percentage content of aromatic carbons is reduced and that of the percentage of paraffinic carbons increases, which has the effect of the viscosity index of the effluent obtained in stage d) in relation to that obtained in stage a). The catalyst of step d) is much more sensitive to interference than those of the first stage. It only works on recycling streams, on total effluents obtained in stage a) or on liquid effluents from a fractionation of the products that come out of stage a).

The unconverted fractions recovered in step a) or d) can be recycled at least in part. The aforementioned fractions have identical boiling points to the charge but different chemical properties. The recycling is carried out either at the level of stage a), or at the level of stage d), or partially in these two stages.

Step b) of the process according to the invention is a step of fractionating at least a part of the effluent obtained in step a) or in step d), in order to separate at least one residue from oils that contain mostly, constituents that have higher viscosity indices than the load. The fractionation is preferably a distillation.

Step c) of the process according to the invention is a thermal diffusion fractionation step of at least a part of the oil residue obtained in stage b) in fractions of oils having high viscosity indexes, preferably greater than about 100 and even more preferably greater than about 140. The oils are separated according to their viscosity index, ie according to their composition in aromatic, naphthenic and paraffinic carbons.

According to the viscosity index of the fractions obtained in step c), said fractions are either recycled, or well recovered. The decision between the recycling or recovery of these fractions is left to the refiner. In a particular way, fractions having viscosity indexes greater than about 140 are recovered. These fractions are rich in paraffinic carbons. Fractions whose viscosity index is light, preferably less than about 100, constitute recycle streams from step c). This recycling is carried out either at the level of stage a), either at the level of stage d), or partially in these two stages. These fractions are generally rich in aromatic carbons and poor in paraffinic carbons.

In the case where the dewaxing is carried out catalytically, catalysts containing at least one zeolite and a hydrogenating hydrogen function can be used.

Preferably, the acid function is ensured by at least one molecular sieve whose microporous system has at least one main type of channels whose openings are formed of rings containing 10 or 9 T atoms. The T atoms are the constituent tetrahedral atoms of the sieve molecular and can be at least one of the elements contained in the set according to the atoms (Si, Al, P, B, Ti, Fe, Ga). In the constituent rings of the channel openings, the T atoms, defined above, alternate with an equal number of oxygen atoms. It is then equivalent to say that the openings are formed of rings containing 10 or 9 oxygen atoms or formed of rings containing 10 or 9 atoms T.

The molecular sieve that enters the composition of the hydrodewaxing catalyst may also contain other types of channels but whose openings are formed of rings containing less than 10 T atoms or oxygen atoms.

The molecular sieve that enters the catalyst composition also has a bridge amplitude, distance between two pore openings, such as defined above, which is at most 0.75 nm (1 nm = lo- "), preferably between 0.50 nm and 0.75 nm, still more preferably between 0.52 nm and 0.73 nm.

The applicant has indeed discovered that one of the determining factors for obtaining good catalytic results in the third stage (hydrodewaxing stage) is the use of molecular sieves having a bridge amplitude of at most 0.75 nm, preferably comprised between 0.50 nm and 0.75 nm, preferably between 0.52 nm and 0.73 nm.

The measure of bridge amplitude is carried out using a graphical and molecular modeling instrument such as Hyperchem or Biosy, which allows to build the surface of the molecular sieves in question and, taking into account ionic radii of the elements present in the screen armor , measure the amplitude d bridge.

The catalyst suitable for this process is characterized by a catalytic test called the standard transformation test of the pure n-decane which is carried out under a partial pressure of 450 kPa of hydrogen and a partial pressure of n-C. 1.2 kPa or a total pressure of 51.2 kPa in fixed bed and with a constant n-Cij flux of 9.5 ml / h, a total flow of 3.6 1 / h and a catalyst mass of 0.2 g. The reaction is performed in downward flow. The conversion rate is regulated by the temperature at which the reaction takes place. The catalyst subjected to the aforementioned test consists of pure, packed, and 0.5% by weight platinum zeolite.

The n-decane in the presence of the molecular sieve and a hydrodehydrogenating function will undergo hydroisomerization reactions that will produce isomerized products of 10 carbon atoms, and hydrofraction reactions that lead to the formation of products containing less than ten carbon atoms. carbon.

Under these conditions, a molecular sieve used in the hydrodewaxing stage according to the invention must have the physico-chemical characteristics described above and lead, for a yield in isomerized products of nCi of the order of 5% by mass (the conversion rate it is regulated by temperature), at a ratio of 2-methyl-nonane / 5-methyl-nonane higher than 5 and preferably greater than 7.

The use of molecular sieves thus selected, under the conditions described above, among the numerous existing molecular sieves, allows in particular the production of products with a slight slip point and high viscosity index with good yields in the framework of the method according to the invention.

The molecular sieves that can enter the composition of the catalytic hydrodewaxing catalyst are, by way of example, the following zeolites: Ferrierite, UN-10, EU-13, EU-1 and the zeolites of the same structural type.

Preferably, the molecular sieves that enter the composition of the hydrodewaxing catalyst are included in the set formed by the ferrierite and the zeolite EU-1.

The mass content in molecular sieves in the dewaxed hisofers catalyst is comprised between 1 and 90%, preferably between 5 and 90% and even more preferably between 10 and 85 '.

The matrices used to carry out the conditioning of the catalyst are, by way of example and without limitation, the alumina gels, the aluminas, the magnesia, the amorphous silica-aluminas, and their mixtures. Such techniques as extrusion, pasting or dragee can be used to perform the conditioning operation.

The catalyst also contains a hydrodehydrogenating function ensured, for example, by at least one element of group VIII and preferably at least one element comprised in the group formed by platinum and palladium. The non-noble metal mass content of group VIII, in relation to the final catalyst, is between 1 and 40%, preferably between 10 and 30 i. In this case the non-noble metal is frequently associated with at least one metal of group VIB (preferred Mo and W). If it is at least one noble metal of group VIII, the mass content in relation to the final catalyst is lower than , preferably less than 3% and even more preferably less than 1.5 t.

In the case of the use of noble metals of group VIII, platinum and / or palladium are preferably located on the matrix, defined as above.

The hydrodesparfin catalyst according to the invention can also contain from 0 to 20%, preferably from C to 10% by mass (expressed in oxides) phosphorus. The combination of metal (s) of group VIB and / or metal (s) of group VIII with phosphorus is particularly advantageous.

A dewaxing can be effected, either on the oil residue before step c (fractionation by thermal diffusion, or on the non-recycled fractions extracted in step c). the dewaxing operation may employ a catalyst containing at least one zeolite or a solvent. The paraffins obtained at the exit of the dewaxing solvent, can be recycled either at stage a) or at the level of stage d) or partially in these two stages. Preferably, dewaxing the solvent is carried out. Said - solvent is heated with the product to be dewaxed then cooled and finally filtered, in view of removing the heavy linear paraffins. Frequently, methyl ethyl ketone or methyl isobutyl ketone is used as the solvent.

The operating conditions of step a) and step d) of the process according to the invention can be identical or different. In these two steps, the absolute pressure is usually between about 2 and 35 MPa, preferably between about 5 and 25 MPa, the temperature is generally between about 300 and 550 ° C, preferably between 320 and 450 ° C, the The hourly space velocity is usually between about 0.01 and 10 h-1, preferably between about 0.01 and 5 h "1. These steps are performed in the presence of hydrogen.The H_VHC ratio is usually between about 50 and 5000 Nirr / m" , preferably between approximately 300 and 3000 NmVpr (Normal cubic meters / cubic meters, normal which means normal conditions of a pressure of 0.1 MPa and a temperature of 25 ° C).

Step c) of the process according to the invention is carried out in at least one thermal diffusion column of a height usually comprised between approximately 0.5 and 30 meters (m), preferably between approximately 0.5 and 20 m. The column comprises two tubes placed one on the other. The space between the two tubes is generally between approximately 1 millimeter (mm) and 20 centimeters (cm). the temperature difference between the inner tube wall and the outer tube wall is usually between about 25 and 300 ° C. The inner tube wall is maintained at a temperature lower than that of the outer tube wall. A thermal equilibrium is established between the two walls, so that, from the head to the bottom of the column, the paraffinic compounds (n and iso), the monocyclic compounds (mononafteños and mono-a romáticos), the dicyclic compounds, the tricyclic compounds are recovered.

Figures 1 to 4 show different embodiments of the method according to the invention.

On Figure 1, the charge containing constituents of boiling points above about 300 ° C is sent by line 1 to reactor 5 containing the hydrotreating catalyst and the hydrogen coming from lines 2, 3 and 4. In these operating conditions described above, the load is almost completely desulfurized, and de-nitrogenated. It is converted into an effluent and its content in percentage of aromatic carbons is reduced.

The effluent leaving line 6 is sent to a separator 7 at high pressure after previous injection of washing water by a line not shown on the figure. The washing water containing the ammonia and a part of the dissolved hydrogen sulfide is evacuated from the separator by a line not shown on the figure. The gas coming from the separator 7 has a high hydrogen content and is evacuated through the line 8 after an eventual washing that allows the elimination of the hydrogen sulfide, by a line not shown on the figure. The aforementioned gases also contain light hydrocarbons having 1 to 4 carbon atoms which are discharged via line 8. The said hydrocarbons can then be used, generally after separation with hydrogen, in the fuel-gas network.

The remaining liquid effluent is then routed to a fractionation device 14 along the line 9. In this device, the lightweight fractions in the top are extracted by line 10, the gasoline fraction, which can be used as catalyst reforming charge, kerosene fraction on line 11, gasoil fraction on line 12 and on the bottom oil residue line 13 that is sent to a column 24 thermal diffusion.

The light fractions are extracted from column 24 by lines 15 to 23. The light fractions extracted by lines 15 to 19 are sent in a dewaxing device to the solvent. The fractions exits from lines 25 to 29 have high viscosity indices. The bottom product of column 24 is recycled by line 31 to the line 1 of input of the load. The paraffins exited from the dewaxing are recycled by line 32 to the reactor.

The embodiment of Figure 2 differs from that of Figure 1 by the dewaxing device 30 placed at the outlet of the fractionation device 14. The dewaxing operation is then carried out on the oily residue. This residue is then routed via line 25 to column 24 of thermal diffusion. The light fractions are extracted by lines 15 to 23. The fractions exits from lines 15 to 19 are recovered, fractions 20 to 23 are recycled by line 26 to reactor 5. The paraffins exited from dewaxing are recycled to reactor 5 by line 27 Figure 3 differs from Figure 2 by the presence of a second reactor 31, located at the outlet of the first reactor 5, which contains a catalyst based on zeolite and necessary hydrogen coming from lines 3 and 4, as well as by a recycling of the light viscosity index fractions at the level of the first and the second reactor. Thus, the light fractions extracted by lines 20 to 23, are recycled to the reactant system by line 26. This recycling is performed to the first reactor 5 by line 28, and to the second reactor 31 by line 29. In addition, the paraffins Dewaxing outputs are recycled to the level of the first reactor 5 by line 34 and to the level of the second reactor 31 by line 33.

The effluent leaving the first reactor via line 6 is routed to the second reactor 31 containing the hydrofraction catalyst. Under the operating conditions described above, the effluent emanating from the first reactor 5 is transformed into an effluent containing essentially kerosene, gasoline oil and an oily residue. The effluent left from the second reactor 31 by the line 32 is sent in a separator 7 at high pressure, after previous injection of washing water by a line not shown on the figure. The washing water containing ammonia and a part of the dissolved hydrogen sulfide is evacuated from the separator by a line not shown on the figure. The gas coming from the separator 7 at high pressure contains a high content of hydrogen sulfide, by a line not shown on the figure. Said gases also contain light hydrocarbons of 1 to 4 carbon atoms in their molecule and are evacuated by line 8. The said hydrocarbons can then be used, after separation with hydrogen, in the fuel-gas network.

The liquid effluent exiting the separator 7 at high pressure is sent by line 9 to a fractionation device 14. The following stages are identical to those in Figure 2.

The embodiment of the process illustrated in FIG. 4 is identical to that of FIG. 3, but the waxing device 30 is located at the outlet of the thermal diffusion column 24 and the paraffins obtained at the exit of the dewaxing are recycled at the level of the second reactor. on line 28.

The following examples illustrate the invention without limiting the scope.

Example 1: The embodiment shown in FIG. 2 is used. The load is a petroleum distillate. Its characteristics are given in Table I.

The charge is sent in a reactor containing a catalyst, in the presence of hydrogen. Said catalyst in the form of extrudates of 1.6 millimeters (mm) in diameter, is based on molybdenum (15: MoO?), Nickel (5 NiO), on an alumina support? (80% of A1_03). The reactor is heated to the temperature of approximately 390 ° C. The hourly space velocity is approximately 0.5-1. The partial pressure of hydrogen is equal to 14.8 MPa and the H2 / HC ratio is 1600 Nm3 / m3.

Under these conditions, the conversion at 375 ° C is approximately equal to 42.7% by mass. This conversion is defined by the ratio between the mass fraction of the effluent that has a boiling point below 375 ° C minus the fraction of the boiling load below 375 ° C, and the fraction of the load that has a point of boiling above 375 ° C. The load is then converted into an effluent containing essentially kerosene, gasoline, diesel and oils.

The effluent exiting the reactor is sent to a high pressure separator to be fractionated in a gaseous effluent containing hydrogen sulfide, ammonia, and light hydrocarbons and that is evacuated, and in an effluent that is routed to the distillation column. Different fractions of the head to the bottom of the column are collected as follows: a gasoline fraction, a kerosene fraction, a gas oil fraction and an oil residue at the bottom of the column.

The oil residue is dewaxed by means of methyl isobutyl ketone as a solvent. It is analyzed below. The paraffins exited from the dewaxing are recycled to the reactor. The characteristics of the charge, as well as the residue obtained after dewaxing the solvent, are presented in Table I below: Characteristics: Residual Load: Voluminous mass at 15 ° C (Kg / m3) 969.0 879.9 refractive index at A 20 ° C 1.5474 1.4835 Kinematic viscosity At 40 ° C (mm / s): 250 72.41 Kinematic viscosity At 100 ° C (mmVs) 15.13 9.03 viscosity index 34 98 Characteristics: Residual Load: Sliding point (° C) -27 -21 Ca 29.3 4.84 Cc 60.5 71.59 cr:%) 10.2 23.57 C5, Cc and C- are respectively the percentage content of aromatic, paraffinic and naphthenic carbons.

The viscosimetric qualities of the charge and the residue are very different. The conversion that is limited, the viscosity index is similarly reduced, remaining completely the same as currently required by the customs specifications.

In addition, the different stages have allowed the hydrogenation of the aromatic compounds and the opening of the naphthenic cycles, which translates into a decrease in the density and an increase in the viscosity index of the oil residue, in relation to the initial load.

A part of the waste then circulates in a column of thermal diffusion, of a height of 2 meters (m) and comprising two tubes placed one on the other. The oily residue circulates in the space formed by the walls of the tubes. This space is approximately 0.25 millimeters (mm). The temperature difference between the inner tube wall and the outer tube wall is approximately 130 ° c.

The thermal diffusion column has 9 lines of extraction of light fractions, which allow to collect fractions of waste. The characteristics of these fractions are given in table 2: Table 2 Number Mass index Cp (%) Cn (%) Of the Fractional volume visco-Nes at 15 ° C sity (kg / m3) 128. 9 16f 1.6 96.7 1.7 137.8 .47 2.0 16.3 11.6! 49.4 140 2. 75.6 21 ¡57.7 127 2.9 69.5 27.6 ¡76.2 103 3.7 55.4 40. ¡92.5 76 4.5 47.5 48.0 907.0 53 5.5 49.1 45.4 922.7 25 6.7 45.2 48.1 942.2 -24 8.9 43.1 48.0 Ca, Cp and Cn are the respective contents in percentages of aromatic, paraffinic and naphthenic carbons.

The thermal diffusion allows, from the waste of oils having a viscosity index of approximately 98, obtain different fractions of oils having different viscosity indexes (from 24 to 168). In this way, different oil compositions are obtained.

The three column head fractions each have a viscosity index greater than or equal to 140. They are poor in aromatic carbons (with a content of 1.6 to 2.6%) and rich in paraffinic carbons (with a content of 76 to 87% ). The column bottom fractions (fractions 6 to 9) are rich in aromatic carbons (4.5 to 8.9%) and naphthenic carbons (45 to 48 -o). Their viscosity indexes are less than 100. These fractions are then recycled at the level of the introduction of the charge.

According to the decision of the refiner, fractions 4 and 5, which have viscosity indexes between about 100 and 130, are either recycled or recovered.

The same load is used as in example 1 but with the embodiment illustrated on figure 3. The characteristics of the load are presented in Table 3. The first stage of hydro catalytic treatment in the first reactor, which contains the charge, the hydrogen and the catalyst based on nickel, molybdenum and alumina, as well as the fractionation step of the effluent left from the first reactor.

The liquid effluent obtained at the outlet of the high pressure separator is introduced into a second reactor, in the presence of a second catalyst. The second catalyst comprises a HY zeolite characterized by 13.6% by mass of Si02, 13.49% by mass of Mo0 ?, 2.93% by mass of NiO, 5.09% by mass of P_0 £ on a support of 64.89% by mass of A1203. The crystalline parameter a of the elementary mesh is 24. 28 10"" ° m, the capacity to retake sodium ions is 0.92, the specific surface area determined by the method B.E.T. is 600 pr / g, the water vapor absorption capacity at 25 at a partial pressure of 2.6 torr (346.63 Pa) is 13% by mass and the porous partition comprises approximately 10% of the pore volume contained in diameter pores located between 10.10"10 m and 80.10 ~ 10 m, the rest of the pore volume that is contained in the pores of diameter less than 20.10" 10 m.

The operating conditions in the second reactor are identical to those carried out in a first reactor (see example 1).

Under these conditions, the conversion at 375 ° C is approximately equal to 79.9% by mass. The effluent leaving the second reactor is sent in a high pressure separator. The effluent is thus fractionated in a gaseous effluent that is evacuated and in a liquid effluent.

The liquid effluent returns to the distillation column. A gasoline fraction, a kerosene fraction, a gas oil fraction and an oil residue are collected from the head towards the bottom of the column.

The residue is dewaxed by means of methyl isobutyl ketone as solvent and its characteristics are presented in table 4. The paraffins exited from the dewaxing are partially recycled at the level of two reactors.

Table 3 Characteristics: Residual Load: Voluminous mass at 15 ° C (Kg / m3) 969.0 847.9 refractive index at 20 ° C 1. 5474 1. 4687 Kinematic viscosity At 40 ° C (mrrr / s): 250 35.51 Kinematic viscosity At 100 ° C (mpr / s) 15.13 6.31 viscosity index 34 129 Slip point (° C) -27 -21 Characteristics: Residual load: C3:%) 29.3 2.8 Cc (%) 60.5 84.79 Ca, CF and Cn are respectively the contents in percentages of aromatic, paraffinic and naphthenic carbons.

The viscosity index of the oil residue (equal to 129), after passing in the two successive reactors, is higher than that of the load (equal to 34), but it is even higher than that of the residue after passing in a single reactor (equal to 98, see example 1). It is the same for the content of paraffinic carbons.

A part of the oil residue is sent in the thermal diffusion column, with characteristics and operating conditions identical to those of example 1.

The separation by thermal diffusion of the oil residue in nine fractions gives the results grouped in table 4: Table 4 Number Mass index Ca (%) Cp (%) Cn (%) Of the volume Fractional visco- Nes a] 5 ° C sity (kg / m3) 1 818.9 205 0.7 93.2 6.1 24.3 182 0.7 92.8 6.5 829. 4 162 79.7 19.8 33.1 154 0.9 77.1 22.0 842.4 128 0.9 64.4 34.7 52.8 122 1.1 63.5 35.4 65.2 100 1.5 59.4 39.1 Table 4 (continued) Number Mass index Ca (%) - CP (%) Cn ('Of the Fractional volume visco- Nes at 15 ° C sity (kg / m3) 8 881.1 81 2.2 54.8 43.0 9 918.4 55 6.4 50.9 42.7 The viscosity indexes are higher than those obtained by operating as described in example 1. It is possible to recover fractions of oils 1 to 4, of viscosity indexes comprised between 150 and 205, as well as fractions 5 and 6 of indexes comprised between 120 and 130. Fractions 7 to 9 are recycled at the level of the introduction of the load.

It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Having described the invention as above, it is claimed as property in the following:

Claims (13)

1. Process for the production of oils having a high viscosity index, from a filler containing constituents with boiling points higher than approximately 300 ° C, characterized in that: a) hydrogen is reacted with the filler or with a mixture of the filler with at least a fraction of a recycle stream from step c), in the presence of a catalyst comprising at least one non-zeolitic amorphous matrix and at least one metal or metal compound of group VIII of the periodic classification of the elements and / or at least one metal of group VIB. b) At least a part of the effluent obtained in step a) is fractioned so as to separate at least one residue of oils that mostly contain constituents having higher viscosity indexes than that of the filler. c) at least a part of the oil residue obtained in stage b) is fractionated by thermal diffusion into fractions of oils having high viscosity indexes, the process which is further characterized in that the oils are separated according to their viscosity index.

2. Process according to claim 1, characterized in that step b) is preceded by a step d) of contacting at least a part of the effluent obtained in stage a), with the hydrogen in the presence of a catalyst comprising at least a zeolite, at least one matrix, and at least one metal or metal compound of group VIII of the periodic classification of the elements and / or at least one metal of group VIB, the effluent obtained in step d) which is sent to stage c).

3. Process according to claim 1 or 2, characterized in that the effluent obtained in step a) or in step d) is fractionated in at least one separator, in at least one gaseous effluent that is evacuated and in at least one liquid effluent, which is sent to stage b).

4. The method according to any of claims 1 to 3, characterized in that the non-converted fractions recovered in stage a) or d) are recycled at least in part, either at the level of stage a), or at the stage level. d), or partially in these two stages.

5. Process according to any of claims 1 to 4 characterized in that the recycle streams of step c) are fractions exits from step c) that have light viscosity indexes, which are recycled either at the level of stage a), either at the level of stage d), or partially in these two stages.

6. Process according to any of claims 1 to 5, characterized in that the oil residue obtained in stage b), and / or the non-recycled fractions extracted in step c) are dewaxed with a catalyst or a solvent, the paraffins exiting from This dewaxing is recycled either at the level of stage a), either at the level of stage d) or partially in these two stages.

7. Process according to any of claims 1 to 6, characterized in that the catalyst matrix of stage a) is selected from the group consisting of alumina, silica, silica-aluminas, clays and mixtures of at least two of these minerals.

8. Process according to any of claims 1 to 7, characterized in that the catalyst of step a) contains a total concentration of metal oxides of groups VIB and VIII comprised of approximately 5 and 40% by mass, and a mass ratio expressed in oxides metals between metal (or metals) of group VI on metal (or metals of group VIII of approximately 20 to 1.

9. Process according to any of claims 2 to 8, characterized in that the zeolite of the catalyst of step d) is an acid zeolite HY characterized by a molar ratio Si02 / Al203 comprised between approximately 8 and 80, a sodium content of less than about 0.15% by mass, determined on zeolite calcined at 1100 ° C; an observed crystalline parameter a, of the elemental mesh • comprised between approximately 24.55.10 ~ 10 meters (m) and 24.24.10"? nm; a capacity CtJa to take sodium ions again, expressed in grams (g) of sodium per 100 g of modified zeolite, neutralized then calcined, greater than about 0.85, a surface area determined by the BET method of more than about 400 pr / g (square meter per gram), a capacity of water vapor assignation at 25 ° C for a partial pressure of 2.6 torrs (ie 346.63 Pa), greater than about 6% by mass, a porous partition comprising between approximately 1 and 20% of the pore volume contained in pores of diameter located between approximately 20.10"10 and 80.10" ~ ° m, the rest of the pore volume that is contained in the pores with a diameter less than 20.10-10 m, a zeolite mass content between 2 and 80% in relation to the catalyst used in step d).

10. Process according to any of claims 2 to 9, characterized in that the matrix of the catalyst of step d) is selected from the group consisting of alumina, silica, silica-alumina, alumina- boron oxide, magnesia , silica - magnesia, zirconium, titanium oxide, clay, these compounds that are useful alone or in mixtures.

11. A process according to any of claims 2 to 10 characterized in that the catalyst of step d) contains a total concentration of oxides of metals of groups VIB and VIII comprised between about 1 and 40% by mass, the mass ratio expressed in metal oxides, between metal (or metals) of group VI on metal (or metals) of group VIII is between about 20 and 1.25 and the concentration of phosphorus oxides is less than about 15 mass%.

12. Process according to one of claims 1 to 11, characterized in that step a) and step d) of the process are carried out at an absolute pressure between approximately 2 and 35 MPa, a temperature between approximately 300 and 550 ° C, a speed hourly space between approximately 0.01 and 10 h-1, in the presence of hydrogen, the H2 / HC ratio that is between approximately 50 and 5000 Nm / m3, the conditions of these two stages being identical or different.

13. Process according to any of claims 1 to 12, characterized in that step c) of the method is carried out in at least one column of thermal diffusion of a height comprised between approximately 0.5 and 30 meters (m) comprising two tubes placed one in the another, the oily residue circulating in the space formed by these two tubes, the space between these two tubes which is comprised between approximately 1 millimeter (mm) and 20 centimeters (cm); the temperature difference between the wall of the inner tube and the wall of the outer tube which is between approximately 25 and 300 ° C, the wall of the inner tube which is maintained at a temperature lower than that of the wall of the outer tube.