MXPA98004625A - Hydrotracting of hydrocarbon loads in a bed reactor f - Google Patents

Abstract

The present invention relates to a catalyst comprising an extruded support essentially based on alumina, and constituted of a plurality of juxtaposed agglomerates and which occur partly in the form of stacks of sheets and partly in the form of needles, and which optionally comprise at least one catalytic metal or a catalytic metal compound of group VIB, and / or optionally at least one catalytic metal or a catalytic metal compound of group VIII. The invention also relates to its use in a fixed bed reactor, for the hydrorefining and hydroconversion of hydrocarbon charges.

Description

HYDROTRACTING OF HYDROCARBON LOADS N A REACTOR D? FIXED BED Field of the Invention The present invention relates to a catalyst for hydrorefining and / or hydroconversion of hydrocarbon fillers (also known as hydrotreating), the catalyst comprises a support essentially based on alumina in the form of extruded materials, optionally at least one metal. catalytic or a catalytic metal compound of the group VIB (group 6 of the new notation of the periodic table of the elements), preferably molybdenum and tungsten, more preferably molybdenum, and / or optionally at least one catalytic metal or a catalytic metal compound of the group VIII (group 8, 9 and 10 of the new notation of the periodic table of the elements), preferably iron, nickel or cobalt. The present invention also relates to processes for the preparation of the catalyst, as well as to its use for hydrorefining and hydroconversion of hydrocarbon fillers such as oil cuts, cuts obtained from coal or hydrocarbons produced from natural gas. Ref .027623 Background of the Invention The hydrotreating of hydrocarbon charges, such as sulfur oil cuts, has taken on greater and greater importance in the practice of refining, with the increasing need to reduce the amount of sulfur in oil cuts and to convert heavy fractions in lighter fractions that can be evaluated as fuel. In fact, it is necessary, both to meet the specifications imposed by each country for commercial fuels and for economic reasons, to better evaluate the imported crude oils richer and richer in the heavy fractions and in heteroatoms and more and more poor in hydrogen. This evaluation implies a relatively significant reduction in the average molecular weights of the heavy constituents, which can be obtained, for example, by means of fractionation or hydrofraction reactions of the previously refined, i.e., -desulfurized and denitrogenated fillers. Van Kessel et al explain this context in detail in an article published in the journal Oil & Gas Journal, dated 16 February 1987 on pages 55 to 56. On the other hand it is already known to the person skilled in the art that at the time of the hydrotreating reactions of the oil fractions containing organometallic complexes, most of the the complexes are destroyed in the presence of hydrogen, sulfur hydrogen, and a hydrotreating catalyst. The metal constituent of these complexes then precipitates in the form of a solid sulphide to be fixed on the inner surface of the pores. This is in particular the case of the complexes of vanadium, nickel, iron, sodium, titanium, silicon, and copper that are naturally present in crude oils with a more or less large abundance depending on the origin of oil, and which, at the time of distillation operations, have a tendency to concentrate in the high-boiling fractions and in particular in the case of waste. This is also the case of liquefied carbon materials that also contain metals, in particular iron and titanium. The general term hydrodesmetallation (HDM) is used to designate these reactions of destruction of organometallic complexes in hydrocarbons. The accumulation of the solid deposits in the pores of the catalyst can be continued until the complete plugging of a part of the pores that command the access of the reactants to a fraction of the interconnected porous network in such a way that this fraction becomes inactive then while at the same time the other pores of this fraction are slightly clogged or even intact.This phenomenon can thus cause a premature and very important deactivation of the catalyst, which is particularly sensitive in the case of hydrodemetalation reactions in the presence of a heterogeneous supported catalyst., is understood not to be soluble in the charge of the hydrocarbons. In this case, it is observed that the pores of the periphery of the grain are clogged faster than the central pores. In the same way, the holes in the pores become clogged more quickly than their other parts. The obstruction of the pores is closely related to a progressive reduction of its diameter, which causes an increased limitation of the diffusion of the molecules and an accentuation of the concentration gradient, such accentuation of the heterogeneity of the deposit from the periphery to the interior of the porous particles to the point where "the complete obstruction of the pores that flow outwards occurs very quickly; the access to the almost intact internal porosity of the particles is then closed to the reactants and the catalyst is prematurely deactivated. The phenomenon that is going to be described is well known under the name of "plugging of the holes in the pores". The proofs of its existence and the analysis of its causes have been published several times in the international scientific literature, for example: "Catalyst deactivation through pore mouth plugging" ("Deactivation of the catalyst by plugging the holes in the pores") in the 5 / o. international symposium on the character of the chemical reaction in Houston, Texas, USA, in March 1978, or even "Effects of feed metais on catalysts aging in hydroprocessing residuum" ("The effects of the feeding of metals during the aging of catalysts in the residues of hydroprocessing "in Industrial Engineering Chemistry Process Design and Development, volume 20, pages 262 to 273 published in 1981 by the American Chemical Society, or even more recently in" Effect of Catalyst for structure on hydrotreating of heavy oil "presented to the National Congress of the American Chemical Society in Las Vegas, USA, on March 30, 1982. A hydrotreating catalyst for heavy hydrocarbon cuts containing metals must thus be composed of a catalytic support having a particularly adapted porosity profile. for specific diffusional restrictions for hydrotreatments and especially for hydro des etalació.

The catalysts usually used in hydrotreating processes are composed of a support on which metal oxides are deposited, such as, for example, cobalt, nickel or molybdenum oxides. The catalyst is then desulfurized to transform all or part of the metal oxides into the phase of the metal sulphides. The support is generally based on alumina, its role is to disperse the active phase and present a texture adapted for a good uptake of metal impurities, avoiding the plugging problems mentioned above. Thus, catalysts having a particular porous distribution are described in US Pat. No. 4,395,329. The alumina-based supports of the prior art are of two types. First, there are extruded alumina materials prepared from an alumina gel. Hydrotreating catalysts prepared from these extruded materials have several drawbacks. First of all, the process for the preparation of the alumina gel is particularly polluting, contrary to that of the alumina, which is derived from the rapid dehydration of hydrargillite, called instant or rapid alumina. Afterwards, the porosity of the supports based on the alumina gel is specially adapted to the hydrodesulfurization «* •• and the hydrotreatment of the light hydrocarbon cuts, and not the other types of hydrotreatments. On the other hand, even when these extruded materials are balanced in their ratio of hydrodesmetalation / hydrodesulphurisation, its retention capacity in hydrodesmetalation is reduced, in general when much in 30% by weight, reason why they are saturated quickly and must be replaced. In addition, taking into account the cost of high production of alumina gel, the manufacture of these catalysts is very expensive. Second, the alumina balls prepared by rapid dehydration of the hydrargilite then the agglomeration of the instant alumina powder obtained, are used as support for hydrotreating catalysts of hydrocarbon charges containing metals. The preparation cost of these balls is less high, however in order to maintain it at a satisfactory level, it is necessary to prepare balls of a diameter greater than 2 mm. Consequently, the metals can not be introduced until the nucleus of the balls, and the catalytic phase that is found there is not used. Hydrotreating catalysts prepared from the extruded materials of instant alumina of smaller size and having a porosity adapted for hydrotreating, would not present all these drawbacks, but there is no industrial process to prepare such catalysts up to now.

Detailed description of the invention The present invention relates to a catalyst for hydrotreating carbonaceous fractions or hydrocarbons, to the processes for preparing said catalyst, as well as to its use- in hydrotreating reactions, especially in hydrogenation, hydrodesnitrogenation, hydrodeoxygenation reactions, " hydrodesaromatization, hydroisomerization, hydrodesalkylation, hydrodewaxing, hydrofractionation, and hydrodesulphurisation which have an activity in hydrodemetalation at least equivalent to that of the catalysts known to date by the person skilled in the art, and allow to obtain particularly high hydrotreating results with respect to The products of the prior art The catalyst according to the invention comprises an essentially alumina-based support in the form of extruded materials, optionally at least one catalytic metal or a catalytic metal compound of group VIB (group 6). of the new notation of the periodic table of the elements), preferably molybdenum and tungsten, still more preferably molybdenum, and / or optionally at least one 'catalytic metal or a catalytic metal compound of group VIII (group 8, 9 and 10 of the new notation of the periodic table of the elements), preferably iron, nickel or cobalt, even more preferred nickel. The extruded support used in the catalyst according to the invention is generally and preferably essentially based on alumina agglomerates, said alumina agglomerates are generally obtained and preferably by the use of a starting alumina obtained from the rapid dehydration of the hydrargilite and which generally have a total porous volume of at least 0.6 cm3 / g, an average mesoporous diameter comprised between 15 and 36 nm (nanometers), and in general a rate or ratio of alumina obtained from the decomposition of the boehmite comprised between 5 and 70 % in weigh. For alumina obtained from the decomposition of the boehmite, it should be understood that in the course of the preparation process of the extruded materials, the alumina of the boehmite type is developed to the point of representing 5 to 70% by weight of the total alumina, then it has been decomposed. This rate or ratio of alumina obtained from the decomposition of the boehmite is measured by the diffraction of the X-rays on the alumina before the decomposition of said boehmite. The extruded support of the catalyst according to the invention can also be obtained by the extrusion of a mixture in variable proportions of an alumina powder obtained from the rapid dehydration of hydrargillite (instant alumina), and of at least one alumina gel obtained for example by precipitation of aluminum salts such as aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum acetate or by hydrolysis of aluminum alkoxides such as aluminum triethoxide. Such mixtures of instant alumina and alumina gel contain less than 50% by weight of the alumina gel and preferably from 1 to 45% by weight of the alumina gel. The catalyst according to the invention can be prepared by any method known to the person skilled in the art, and more particularly by following the methods described below. The extruded alumina materials with a diameter generally between 0.5 and 10 mm, preferably between 0.8 and 3.2 mm when the catalyst is used in a fixed bed are used as support, said extruded materials have the characteristics described above. On these extruded materials, prior to the extrusion forming, any known method may be introduced, and it does not matter at which stage of preparation, preferably by impregnation or co-kneading, the catalytic metals, that is to say optionally at least one catalytic or a catalytic metal compound of group VIB (group 6 of the new notation of the periodic table of the elements), preferably molybdenum and tungsten, still more preferably molybdenum, and / or optionally at least one catalytic or a catalytic metal compound of group VIII (group 8, 9 and 10 of the new notation of the periodic table of the elements), preferably iron, nickel or cobalt, even more preferably nickel. Said metals can optionally be mixed with the support by co-kneading at any stage of the preparation process of said support. When several are present, said metals of groups VIB and VIII may optionally be introduced at least in part separately or simultaneously at the time of impregnation or co-kneading with the support, at any stage of the shaping or preparation. For example, it is possible to prepare the catalyst according to the invention by means of a preparation process comprising the following steps: a) Co-masking the alumina powder obtained from the rapid dehydration of hydrargillite with at least one catalytic metal compound of group VIB, and / or at least one catalytic metal compound of group VIII, optionally followed by maturation, and / or drying, then optionally a calcination. b) Conform by extrusion of the product obtained in stage a.

The above-mentioned metals are more frequently introduced in the form of precursors, such as oxides, acids, salts, organic complexes, into the catalyst. The sum S of the metals of groups VIB and VIII expressed in the oxides introduced into the catalysts is between 0 and 50% by weight, preferably 0.5 to 50% by weight, more preferably 0.5 to 40% by weight. weight. It is thus possible according to the invention to use the support as catalysts without introducing the catalytic metal into said catalyst. The preparation generally comprises maturation and drying, then generally a heat treatment, for example a calcination, at a temperature between 400 and 800 degrees centigrade.

The support whose use is one of the essential elements of the invention is essentially based on alumina. The support used in the catalyst according to the invention is generally and preferably obtained by the formation of a starting alumina, obtained from the rapid dehydration of the hydrargillite, said conformation being preferably carried out by means of one of the methods described hereinafter. The preparation methods of the support according to the invention are described below, for a support consisting of alumina. When the support contains one or more other compounds, it is possible to introduce said or said compound or a precursor of said or said compounds, regardless of which stage of the preparation process of the support according to the invention. It is also possible to introduce said or said compounds by impregnating the formed alumina by means of said or said compounds or any precursor of said or said compounds. A first process for shaping a starting alumina obtained from the rapid dehydration of hydrargillite comprises the following steps: ai. separating an alumina obtained from the rapid dehydration of iarglycite, i. rehydrate the starting alumina, Ci. kneading the rehydrated alumina in the presence of an emulsion of at least one hydrocarbon in water, di. extruding the alumina-based paste obtained in step Ci, ßi. drying and calcining the extruded materials, fi. subjecting the extruded materials obtained from step ei to an acidic hydrothermal treatment in a confined atmosphere, gi. drying and calcining the extruded materials obtained from step £? .

A second process for shaping alumina from a starting alumina obtained from the rapid dehydration of hydrargillite comprises the following steps: a2. Separate an alumina obtained from the rapid dehydration of hydrargillite, b2. to form the alumina in the form of beads in the presence of a porogen, C2. ripen the obtained alumina balls, efe. knead the balls obtained from step c2 whereby a paste is obtained that is extruded, e2. dry and calcined the extruded materials obtained, f2. subjecting the extruded materials obtained from step ß2 to an acid hydrothermal treatment in a confined atmosphere, g2. drying and calcining the extruded materials obtained from step f2.

A third process for shaping an alumina, starting from a starting alumina obtained from the rapid dehydration of hydrargillite, comprises the following steps: a3. Separate an alumina obtained from the rapid dehydration of hydrargilite, b3. rehydrate the starting alumina, c3. kneading the rehydrated alumina with a pseudo-boehmite gel, said gel is present in a content comprised between 1 and 30% by weight with respect to the rehydrated alumina and the gel, d3. Extrude the alumina-based paste obtained in step c3, e3. drying and calcining the extruded materials, f3. subjecting the extruded materials of step e3 to an acidic hydrothermal treatment in a confined atmosphere, g3. drying and calcining the extruded materials obtained from step f3.

This procedure uses stages identical to steps ai, bi, di, ei, fi and gi of. first procedure previously described. On the contrary, according to step c3, the rehydrated alumina obtained from step b3 is kneaded not with an emulsion of hydrocarbons, but with a pseudo-boehmite gel in a content comprised between 1 and 30% by weight with respect to the rehydrated alumina and gel, preferably between 5 and 20% by weight. One such pseudo-boehmite gel can be obtained by precipitation of the aluminum salts such as aluminum chloride, aluminum sulfate, aluminum nitrate, aluminum acetate with a base or by the hydrolysis of aluminum alkoxides such as aluminum triethoxide. The kneading can be carried out in any way known to the person skilled in the art, and especially with the help of a mixer with arms in Z or a double screw mixer. Water can be added to adjust the viscosity of the paste to be extruded. The extruded alumina materials according to the invention generally and preferably have a total pore volume (VTP) of at least 0.6 cm3 / g, preferably of at least 0.65. This VPT is measured in the following way: the value of grain density and absolute density is determined: grain (Dg) and absolute (Da) densities are measured by the pycnometry method respectively of mercury and helium, The VPT is given by the formula: VPT = Dg Da The extruded materials according to the invention also generally have a mesoporous average diameter of between 150 and 100.degree. 360 A (Angstroms). The average mesoporous diameter for the given extruded materials is measured on the basis of "the graphic representation of the porous distribution of said extruded materials, it is the diameter whose associated volume V on the graphic representation is: V = V100r Vßrun ~ VlOOr with Vxoop q e represents the volume created by the pores with a diameter greater than 100 n (macropores) or the macroporous volume. Veran represents the volume created by pores with a diameter greater than 6 nm. Vßnm-ioonm represents the mesoporous volume ie the volume created by pores with a diameter between 6 nm and 100 nm, ie the volume created by all pores of size between 6 nm and 100 nm (mesopores). These volumes are measured by the mercury penetration technique in which the Kelvin law is applied, which gives the relation between the pressure, the smallest pore diameter in which the diameter penetrates to said pressure, the angle of soaking and Surface tension according to the formula: 0 = (4t cos?). 10 / P in which 0 represents the pore diameter (nm) t the surface tension (48.5 Pa),? the contact angle, (? = 140 degrees) and P the pressure (MPa).

Preferably, the extruded materials according to the invention have a mesoporous volume (V6nm-V10onm) of at least 0.3 cm3 / g, even of at least 0.5 cm3 / g.

Preferably, the extruded materials according to the invention have a macroporous volume (Vioonm) of at most 0.5 cm 3 / g. According to a variant, the macroporous volume (Vioonm) when much of 0.3 cm3 / g, even more preferably when much of 0.1 cm3 / g even when much of 0.08 cm3 / g. Usually, these extruded materials have a microporous volume (V0-6nm) when much of 0.55 cm3 / g, preferably when much of 0.2 cm3 / g. The microporous volume represents the volume created by pores with a diameter less than 6 nm. One such porous distribution that minimizes the proportion of the pores below 6 nm and those greater than 100 nm while increasing the proportion of the mesopores (whose diameter is between 6 nm and 100 nm) is particularly adapted to the restrictions diffusional hydrotreatment of heavy hydrocarbon cuts. According to a preferred variant, the porous distribution over the domain of the pore diameter between 6 nm and 100 nm (mesopores) is extremely close to 15 nm, that is to say that over said domain the majority of the pores have a diameter comprised between 6 and 10 nm. nm and 50 nm, preferably between 8 nm and 20 nm.

The extruded materials according to the invention can generally have a specific surface area (SS) of at least 120 m2 / g, preferably of at least 150 m2 / g. This surface is a BET surface. BET surface is defined as the specific surface area determined by the adsorption of nitrogen according to ASTM D 3663-78 standard established by the BRUNAUER-EMETT-TELLER method described in the newspaper "The Journal of the American Society", 60, 309 (1938). The extruded materials according to the invention are preferred whose diameter is between 0.5 and 10 mm, preferably between 0.8 and 3.2 mm, and the length comprised between 1 mm and 20 mm, preferably between 1 and 10 mm, especially when said catalyst is used in a fixed bed. These extruded materials generally have a crushing or reduction of grain to grain (EGG) of at least 0.68 daN / mm for extruded materials with a diameter of 1.6 mm, preferably at least 1 mm, and a crush resistance (ESH). of at least 1 MPa. The method of measurement of the crushing of grain to grain (EGG) consists of measuring the form of the maximum compression that an extruded material can support before its rupture, at the moment in which the product is placed between two planes that move to the constant speed of 5 cm / min.

The compression is applied perpendicularly to one of the generatrices of the extruded material, and the crushing of grain to grain is expressed as the ratio of the force with respect to the length of the generatrix of the extruded material. The method for measuring the crush resistance (ESH) consists in subjecting a certain amount of the extruded materials to an increasing pressure above a screen and in recovering the fine materials obtained from the crushing of the extruded materials. The crushing strength * corresponds to the force exerted to obtain a fine material rate that represents 0.5% of the weight of the extruded materials subjected to the test. The alumina according to the invention consists essentially of a plurality of juxtaposed agglomerates, each of these agglomerates is generally and preferably partly in the form of stacks of sheets and partly in the form of needles, said needles being uniformly dispersed turn around the stacks of leaves and between the leaves. In general, the length and width of the leaves varies between 1 and 5 μm and its thickness is of the order of nm. They can be stacked by groups forming a thickness of the order of 0.1 to 0.5 μm, the groups can be separated from one another by a thickness of the order of 0.05 to 0.1 μm. The length of the needles can be between 0.05 and 0.5 μm; its section is of the order of 10 to 20 nm. These dimensions are given by the measurement on the photographs of the extruded materials taken in the electron microscope. Alumina sheets mainly comprise alumina? and the alumina? and the needles of the alumina? The structure of the leaves is characteristic of the filiation of the hydrargilite of the alumina, which means that these materials extruded before the activation by calcination present this same structure, the leaves are of the nature of the hydrargilite. By calcination, this alumina in the form of hydrargilite is mainly transformed into dehydrated aluminas? Y ?. On the contrary, the needle structure is characteristic of the filiation of the boehmite, which means that these materials extruded before activation by calcination present this same structure, the needles are of the nature of the boehmite. Then, by calcination, this alumina in the form of boehmite is transformed into dehydrated alumina? The extruded materials according to the invention are thus obtained by calcination, the materials extruded before the calcination are constituted by sheets based on hydrargilite alumina, said leaves are surrounded at their periphery with needles based on boehmite alumina. The production process according to the invention is more particularly suited to a starting alumina obtained from the rapid dehydration of Bayer hydrate (hydrargillite), which is an industrial aluminum hydroxide which is easily accessible and very well commercialized. One such alumina is obtained especially by the rapid dehydration of the hydrargilite with the help of a stream of hot gases, the inlet temperature of the gas in the apparatus generally varies from 400 to 1200 ° C, the contact times of the alumina with hot gases are generally between a fraction of a second and 4-5 seconds; one such method of preparation of the alumina powder has been described in particular in the patent FR-A-1 108 011. The alumina thus obtained can be used as such or can undergo before the stage bx a treatment to eliminate especially the alkaline substances present: a Na20 content of less than 0.5% by weight may be preferred. Preferably, the starting alumina is rehydrated in the course of step bi so that it exhibits an alumina rate of the boehmite type of at least 3% by weight, preferably at most 40% by weight. The various steps of these processes for preparing alumina edates are described in more detail in a patent application entitled "Edés d 'alumine, leu procedes de préparation et leur utilisation comme catalyseurs or supports de catalyseurs" ("Eded materials"). of alumina, its preparation processes and its use as catalysts or catalyst supports "), by Rhone Poulenc Chimie. The catalysts according to the invention can thus, in particular, be used in all hydrostatic and hydroconversion processes of hydrocarbon fillers, such as oil cuts, cuts obtained from coal, ects from bituminous sands and bituminous shales. , or the hydrocarbons produced from natural gas and more particularly for hydrogenation, hydrodesnitrogenation, hydrodeoxygenation, hydrodesaromatization, hydroisomerization, hydrodealkylation, hydrodewaxing, dehydrogenation, hydrofractionation, hydrodesulphurisation and hydrodemetalization of hydrocarbon charges containing aromatic, and / or olefinic compounds , and / or naphthenics, and / or paraffinics, said fillers optionally contain metals, and / or nitrogen, and / or oxygen, and / or sulfur. It is possible in particular, by modifying the preparation parameters of the support, essentially based on alumina, obtaining different porous distributions and thus modifying the hydrodesulfurization (HDS) and hydrodemetalization (HDM) rates. Hydrorefining and hydroconversion reactions of hydrocarbon charges (hydrotreating) can be carried out in a reactor containing the catalyst according to the invention, placed in a fixed bed. Said hydrotreatments can be applied, for example, to petroleum fractions such as crude oils of API grade lower than 20, extracts from bituminous and bituminous sands, atmospheric residues, residues under vacuum, asphalts, deasphalted oils, deasphalted vacuum residues, crude deasphalted oils, heavy fuels, atmospheric distillates and vacuum distillates, or even other hydrocarbons such as carbon liquefaction agents. In a fixed-bed process, hydrotreatments intended to remove impurities such as sulfur, nitrogen, metals, and to lower the average boiling point of these hydrocarbons are usually used at a temperature of about 320 to about 450 degrees C, preferably about 350 to 430 degrees C, under a hydrogen partial pressure of about 3 MPa (mega Pascals) to about 30 MPa, preferably 5 to 20 MPa, at a space velocity of about 0.1 to about 5 volumes of charge per catalyst volume and per hour, preferably from 0.2 to 1 volume per volume of catalyst and per hour, the ratio of hydrogen gas to the liquid hydrocarbon charge is between 200 and 5000 normal cubic meters per cubic meter (Nm3 / m3) , preferably between 500 and 1500 (NmVrn3). The examples given below illustrate the invention without limiting the scope.

Example 1: Preparation of alumina support A entering the composition of the catalysts Al and A2 according to the invention.

Stage ai - Starting Alumina - The raw material is the alumina obtained by the very rapid decomposition of the hydrargilite in a stream of hot air (T = 1000 ° C). The product obtained consists of a mixture of transition aluminas: aluminas (khi) and (rho). The specific surface of this product is 300 m2 / g and the loss to fire (PAF) of 5%.

Stage bi - Rehydration - The alumina is subjected to a rehydration by conversion into a suspension in water at a concentration of 500 g / 1 at a temperature of 90 ° C for a time interval of 48 h in the presence of 0.5% citric acid. After filtration of the suspension, an alumina cake is recovered which is washed with water then dried at a temperature of 140 ° C for 24 h. The alumina obtained is in the form of a powder, its fire loss (PAF) measured by calcination at 1000 ° C, and its alumina rate in the form of boehmite, measured by X-ray diffraction, are collected or displayed in Table 1 Stage Ci - Kneading - 10 kg of the rehydrated powder is introduced and dried in a kneaded mixer with Z arms of volume of 25 1, then a hydrocarbon emulsion in water stabilized by a surfactant, previously obtained in a reactor, is added little by little. agitated, and 69% nitric acid. The characteristics are collected or shown in table 1.

The kneading is prolonged until obtaining a constant homogeneous paste. At the end of the kneading, a 20% ammonia solution is added so that the excess of nitric acid is neutralized by continuing the kneading for 3 to 5 minutes.

Stage di - Extrusion - The obtained paste is introduced in a single screw extruder to obtain raw extruded materials with a diameter of 1.6 mm.

Stage ßi - Drying / calcination - The extruded materials are then dried at 140 ° C for 15 h and calcined for 2 h at a temperature of 680 ° C. The support thus calcined has a specific surface area of 148 m2 / g.

Stage fi - Hydrothermal treatment - The extruded materials obtained are impregnated with a solution of nitric acid and acetic acid in the following concentrations: 3.5% of nitric acid with respect to the weight of alumina and 6.5% of acetic acid with respect to the weight of the alumina. Then they are subjected to a hydrothermal treatment in a rotating basket autoclave under the conditions defined in table 1.

Stage gx - Drying / calcination - At the end of this treatment the extruded materials are subjected to a calcination at a temperature of 550 ° C for 2 h. The rate of the boehmite indicated in table 1 is measured on the extruded materials before the final calcination. The support of extruded alumina A is thus obtained, whose characteristics are collected or shown in table 1.

Example 2: Preparation of Al catalyst (according to the invention).

The extruded support A of Example 1 was dry impregnated with an aqueous solution containing the molybdenum and nickel salts. The molybdenum salt is the ammonium heptamolybdate Mo7024 (NH4) 6-4H20 and that of the nickel is the nickel nitrate Ni (N03) 2.6H20. After ripening at room temperature in a water-saturated atmosphere, the impregnated extruded materials are dried overnight at 120 ° C then calcined at 550 ° C for 2 hours under air. The final content in molybdenum trioxide is 6.5% by weight and that in a NiO nickel oxide is 1.4% by weight.

Example 3: Preparation of catalyst A2 (according to the invention).

The extruded support A of Example 1 was dry impregnated with an aqueous solution containing nickel salts (nickel nitrate (Ni (N03) 2.6H20) After maturing at room temperature in a water-saturated atmosphere, the materials extruded impregnated are dried overnight at 120 ° C then calcined at 550 ° C for 2 hours under air.The final content of NiO nickel oxide is 5% by weight.

Example 4: Preparation of the support of alumina B that enters the composition of the catalyst B according to the invention.

The same steps as in Example 1 are used except that the kneading step cl is used in the following manner.

Stage Ci - Kneading - This is a continuous process in a mixer with two screws that are co-rotating. Upstream of the kneader, the rehydrated alumina powder is introduced and dried at a flow rate of 90 kg / h.

In a stirred reactor, a petroleum emulsion is prepared in water, introducing: 5.46 kg of water, 10.04 kg of 69% nitric acid, - 10.4 kg of oil, 1.56 kg of Soprophor SC138.

This emulsion is introduced at a rate of 27.46 kg / h into the sleeve or sheath of the double screw machine immediately followed by the introduction of the alumina powder. At the end or end of the machine, a 28% ammonia solution is introduced at the rate of 4. 34 kg / h. The dust run time in the machine is of the order of 50 to 60 s. At the exit of the machine, a homogeneous paste is obtained that can be extruded. The boehmite rate is measured on the extruded materials before the final calcination. The support of extruded alumina B is thus obtained, whose characteristics are collected or shown in table 1.

Table 1 fifteen twenty Example 5: Preparation of catalyst B (according to the invention).

The extruded support of Example 4 is impregnated dry with an aqueous solution containing molybdenum and nickel salts. The molybdenum salt is the ammonium heptamolybdate Mo 024 (NH4) 6.4H20 and that of the nickel is the nickel nitrate Ni (N03) 2.6H20. After ripening at room temperature in an atmosphere saturated with water, the impregnated extruded materials are dried overnight at 120 ° C then calcined at 550 ° C for 2 hours under air. The final content of molybdenum trioxide is 12.5% by weight and that of NiO nickel oxide is 3.0% by weight.

Example 6: Preparation of the alumina C support that enters the composition of the catalysts Cl and C2 according to the invention.

Step a2 - Starting alumina - The same alumina as in the example is used Stage b2 - Ball formation - The alumina is mixed with the wood flour as porogen (20% by weight with respect to the alumina), then formed into a rotating bowl granulator. To allow conformation, water is added. The alumina balls obtained have a diameter between 1.5 and 4 mm.

Stage c2 - Maturation of the balls - These balls are matured by the passage of water vapor, the temperature of the balls imposed is 90 ° C for 20 h. The balls obtained have a fire loss of 47.5% and contain 25% by weight of boehmite.

Stage d2 - Kneading / extrusion - The kneading procedure used is a continuous process in a mixer with two co-rotating screws. Upstream of the kneader, alumina balls are introduced at a flow rate of 90 kg / h. In the cap or casing immediately following the introduction of the mature balls, a 2.42% nitric acid solution is introduced at a flow rate of 10.9 kg / h. At an end or end of the machine, a 2.1% ammonia solution is introduced at a flow rate of 4.2 kg / h. The pass time of the material to the machine is of the order of 50 s. At the exit of the kneader, a homogeneous alumina paste is obtained that can be extruded.

The paste obtained is extruded through a row that has holes with a diameter of 1.6 mm.

Step ß2 - Drying / calcination - The extruded materials are then dried at 140 ° C for 2 h and calcined for 2 h at a calcination temperature indicated in table 3. The extruded materials thus calcined have a specific surface area that is adjusted to between 120 and 120 ° C. 200 m2 / g.

Stage £ 2 - Hydrothermal treatment - The extruded materials obtained are impregnated with a solution of nitric acid and acetic acid in the following concentrations: 3.5% of nitric acid in relation to the weight of alumina and 6.5% of acetic acid in relation to the alumina weight. Then they are subjected to a hydrothermal treatment in a rotating basket autoclave under the conditions defined in table 2.

Step g2 - Drying / calcination - At the end of this treatment the extruded materials are subjected to a calcination at a temperature of 550 ° C for 2 h. The boehmite rate is measured on the extruded materials before the final calcination. The support of extruded alumina C is thus obtained, whose characteristics are collected or shown in table 2. Table 2 Example 7: Preparation of the catalyst Cl (according to the invention) The extruded support of Example 6 is impregnated dry with an aqueous solution containing molybdenum and nickel salts. The molybdenum salt is the ammonium heptamolybdate Mo7024 (NH4) 6.4H20 and that of the nickel is the nickel nitrate Ni (N03) 2.6H20. After ripening at room temperature in a water-saturated atmosphere, the impregnated extruded materials are dried overnight at 120 ° C then calcined at 550 ° C for 2 hours under air. The final content of molybdenum trioxide is 11.8% by weight and that of NiO nickel oxide is 2.5% by weight.

Example 8: Preparation of catalyst C2 (according to the invention).

The extruded support of Example 6 is impregnated dry with an aqueous solution containing the salts of ammonium heptamolybdate Mo7024 (NH4) 6.4H20. After ripening at room temperature in a water-saturated atmosphere, the extruded materials are dried overnight at 120 ° C then calcined at 550 ° C for 2 hours under air. The final content of molybdenum trioxide is 12.2% by weight.

Example 9: Preparation of support D (comparative).

Alumina balls are prepared from the starting alumina of Example 1. The alumina is milled in a ball mill, to obtain a powder whose average diameter of the particles is 7 μm. This alumina is mixed with wood flour as a porogen (15% in the wood), then it is formed into a granulator or dragee-forming device. To allow conformation, water is added. The balls obtained are dried and calcined, then subjected to a stage of maturation by the passage of water vapor at 100 ° C for 24 hours. These balls are immersed in a solution of acetic acid at 50 g / 1 for approximately 5 hours. They are then removed from the solution, drained then placed in an autoclave for approximately 2 hours, at a temperature of 210 ° C under a pressure of 20.5 bars. At the outlet of the autoclave, the balls are dried for 4 hours at 100 ° C and calcined for 2 hours at 650 ° C.

The balls of granulometry between 1.2 and 2.8 mm are selected.

Example 10: Preparation of catalyst D (comparative).

The support D in the form of beads of Example 9 is impregnated dry by an aqueous solution containing molybdenum and nickel salts. The molybdenum salt is the ammonium heptamolybdate Mo7024 (NH4) 6-4H20 and that of the nickel is the nickel nitrate Ni (N03) 2.6H20. After ripening at room temperature in a water-saturated atmosphere, the impregnated extruded materials are dried overnight at 120 ° C then calcined at 550 ° C for 2 hours under air. The final content of molybdenum trioxide is 11.0% by weight and that of NiO nickel oxide is 2.6% by weight. The characteristics of the obtained catalyst balls D are collected or shown in table 3.

Table 3 Example 11: Tests of hydroconversion of oil residues by the catalysts Al, A2, B, Cl, C2 and D The previously described Al, A2, B, Cl, C2 and D catalysts have been compared in the hydrotreatment test of the different oil residues. It is first of all ^ r. atmospheric residue (RA) of petroleum of Middle East origin (Light of Arabia) and another part of atmospheric residue of extra heavy crude oil; Venezuelan (Boscan). These two residues are characterized by high viscosities, large contents of Conradson carbon and asphaltenes. ? RA Boscan also contains very large contents of nickel and vanadium. The characteristics of these residues are reported in the following table: fifteen twenty The tests are carried out in a pilot unit for hydrotreating the oil residues carried by a fixed-bed tubular reactor. The reactor is filled with one liter of catalyst. The output of the fluids (oil residue + hydrogen recycling) is ascending towards the reactor. This type of pilot unit is representative of the operation of one of the reactors of the HYVAHL unit of the IFP for hydroconversion of waste in fixed beds. After a sulphuration step by the circulation in the reactor of a gasoil cut added with DMDS at a final temperature of 350 ° C, the unit is operated with the oil residues described above, under the following operating conditions: It begins by injecting the RA Arabian Ligth (RA light oil of Arabia). After a stabilization period of 250 hours, the operations in the hydrosulfurization (HDS) and in the hydrosmetallization (HDM) are the following: The HDS rate is defined as follows: HDS (% by weight = ((% by weight of S) load - (% by weight of S) recipe) / (% by weight of S) load * 100 The HDM rate is defined as follows: HDM (% by weight) ((ppm by weight of Ni + V) charge - (ppm by weight of Ni + V) eceta) / (ppm by weight of Ni + V) charge * 100 The charge is then changed to step 3 for the Boscan atmospheric waste. The conduction of the test contemplates to maintain a constant rate of HDM around 80% in weight throughout the cycle. For this reason, deactivation of the catalyst is compensated for by a progressive increase in the temperature of the reaction. The test is stopped when the reaction temperature reaches 420 ° C, a temperature considered representative of the end-of-cycle temperature of an industrial unit of hydroconversion of the waste. The following table compares the amounts of nickel + vanadium that come from the RA Boscan deposited on the 6 catalysts as well as the HDS level in the middle of the cycle.

It thus appears that HDM catalysts in the form of the extruded materials of the present invention can lead to higher HDS performances than those of catalyst D (comparative example) assuring identical operations in turn of HDM and retention of nickel metals + vanadium. The upper HDS runs are observed at a time over an atmospheric residue of light Arabian oil and Boscan. By varying the parameters of preparation of the alumina, it is possible to obtain different porous distributions and thus modify the rates of HDS and HDM.

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, property is claimed as contained in the following

Claims (19)

1. A catalyst comprising an extruded support essentially based on alumina, and consisting essentially of a plurality of juxtaposed agglomerates, optionally at least one catalytic metal or a catalytic metal compound of group VIB (group 6 of the new notation of the periodic table of the elements), and / or optionally at least one catalytic metal or a catalytic metal compound of group VIII (group 8, 9 and 10 of the new notation of the periodic table of the elements), in which the sum S of the metals of groups VIB and VIII expressed in the oxides is between 0% and 50% by weight, and characterized in that each of these agglomerates appears in part in the form of "stacks of leaves and partly in the form of needles , said needles are uniformly dispersed in turn around the stacks of the leaves and between the leaves.

2. The catalyst according to claim 1, characterized in that it does not contain metals (S = 0% by weight).

3. The catalyst according to claim 1, characterized in that the sum S is comprised between 0.5 and 50% by weight.

4. The catalyst according to any of claims 1 to 3, characterized in that the alumina agglomerates are obtained by the formation of a starting alumina obtained from the rapid dehydration of the hydrargillite, and in which the rate of the alumina obtained from the the decomposition of the boehmite is between 5 and 70% by weight.

5. The catalyst according to any of claims 1 to 4, characterized in that the total pore volume is at least 0.6 cm 3 / g, and the mesopores have an average diameter comprised between 15 and 36 nm.

6. A catalyst according to any of claims 1 to 5, characterized in that the Vonm-Vioonm mesoporous volume is at least 0.3 cm3 / g, the macroporous volume V10onm is at most 0.5 cm3 / g, and the microprecious volume V0-6n It is when much of 0.55 cm3 / g.

7. The catalyst according to any of claims 1 and 3 to 6, characterized in that the catalytic metal or the catalytic metal compound of group VIB is molybdenum or tungsten, and the catalytic metal or the catalytic metal compound of group VIII is iron, nickel or cobalt.

8. The catalyst according to any of claims 1 and 3 to 7, characterized in that the catalytic metal or the catalytic metal compound of group VIB is molybdenum, and the catalytic metal or the catalytic metal compound of group VIII is nickel.

9. The catalyst according to any of claims 1 to 8, characterized in that the extruded materials of the alumina have a diameter comprised between 0.5 and 10 mm.

10. A process for the preparation of a catalyst according to any of claims 1 to 9, characterized in that it comprises the following steps: a) Formation of a support essentially based on alumina to obtain the extruded materials. b) Impregnation of the extruded materials with a solution containing at least one catalytic metal compound of group VIB, optionally followed by maturation, and / or drying, followed by calcination. c) Impregnation of the extruded materials with a solution containing at least one group VIII catalytic metal compound, optionally followed by maturation, and / or drying, followed by calcination.

11. The process for preparing a catalyst according to any of claims 1 to 9, characterized in that it comprises the following steps: a) Conformation of a starting alumina to obtain the extruded materials. b) Impregnation of the extruded materials with a solution containing at least one catalytic metal compound of group VIB, and at least one catalytic metal compound of group VIII, optionally followed by maturation, and / or drying, then eventually a calcination.

12. The process for preparing a catalyst according to any of claims 1 to 9, characterized in that it comprises the following steps: a) Coamasing the alumina powder obtained from the rapid dehydration of the hydrargillite with at least one catalytic metal compound of group VIB, and / or at least one catalytic metal compound of group VIII, optionally followed by ripening, and / or of a drying, then eventually of a calcination. b) Conformation by extrusion of the product obtained in stage a.

13. The process for preparing a catalyst according to any of claims 10 to 12, characterized in that the process for forming the starting alumina comprises the following steps: ai. separating a starting alumina obtained from the rapid dehydration of hydrargilite, bi. rehydrate the starting alumina, Ci. kneading the rehydrated alumina in the presence of an emulsion of at least one hydrocarbon in water, di. Extrude the alumina-based paste obtained in stage cx, ßi. drying and calcining the extruded materials, fi. subjecting the extruded materials obtained from step ei to an acidic hydrothermal treatment in a confined atmosphere, gi. drying and calcining the extruded materials obtained from stage fi.

14. The process for preparing a catalyst according to any of claims 10 to 12, characterized in that the process for shaping the starting alumina comprises the following steps: aß. separating a starting alumina obtained from the rapid dehydration of hydrargillite, b2. to form the alumina in the form of beads in the presence of a porogen, C2. ripen the obtained alumina balls, d2. knead the balls obtained from stage 02 whereby a paste is obtained that is extruded, e2. drying and calcining the obtained extruded materials, 2. subjecting the extruded materials obtained from step 62 to an acidic hydrothermal treatment in a confined atmosphere, drying and calcining the extruded materials obtained from the step £ z.

15. The process for preparing a catalyst according to any of claims 10 to 12, characterized in that the process for shaping the starting alumina comprises the following steps: &3. Separate an alumina obtained from the rapid dehydration of hydrargilite, b3. rehydrate the starting alumina, c3. kneading the rehydrated alumina with a pseudo-boehmite gel, said gel is present in a content comprised between 1 and 30% by weight with respect to the rehydrated alumina and ge i, d3. Extrude the alumina-based paste obtained in step c3, e3. drying and calcining the extruded materials, f3. subjecting the extruded materials obtained from step e3 to an acidic hydrothermal treatment in a confined atmosphere, g3. drying eventually, and calcining the extruded materials obtained from step f3.

16. The use of a catalyst according to any of claims 1 to 9, or the preparation according to any of claims 10 to 15, in a hydrotreating process of a hydrocarbon charge, in which the catalyst is used in a fixed bed .

17. The use according to claim 16, characterized in that the hydrocarbon charge contains vanadium and / or nickel and / or iron and / or sodium and / or titanium and / or silicon, and / or copper.

18. The use according to any of claims 16 to 17, in which the charge of the hydrocarbons contains sulfur and / or nitrogen and / or oxygen. <

19. The use according to any of claims 16 to 19, wherein the hydrotreating process is used at a temperature from 320 to about 450 ° C, under a partial pressure of hydrogen of about 3 MPa to about 30 MPa, at a space velocity of about 0.1 to about 5 volumes of charge per volume of catalyst per hour, the ratio of gaseous hydrogen over the liquid charge of 10 hydrocarbons are between 200 and 5000 normal cubic meters per cubic meter (Nm3 / m3). fifteen twenty 25