MXPA01008290A - Multifunctional catalytic composition for the. - Google Patents

Abstract

HYDROTREATMENT OF HEAVY OILS The present invention depicts a catalyst composition for hydrodemetallizing, hydrodesulfurization, hydro- denitrogenation and hydrodisintegration of heavy oils, which employs a support elaborated from a bohemite modified with an oxide of a metal in Group IVB of the Periodic Table of the Elements, chiefly Titania in its anatase phase or the mix of anatase-rutile, by the technique of codeposition or coprecipitation. The support is put under a drying stage ranging between 80 and 120°C and put under calcination at 500 to 550°C in oxidant atmosphere of 3 to 5 hrs. Subsequently, the support obtained in the previous stage is impregnated with an aqueous solution, by the technique of spray-co-impregnation of metals in Groups VA, VIB and VIII; then a rest or aging for a time of 10 to 15 hrs is carried out, the impregnated support is dried at a temperature of 80 to 120°C for 4 to 8 hours, and finally the impregnated support is calcined in oxidant atmosphere at a temperature ranging between 450 to 550°C for a time of 3 to 6 hours.

Description

MULTIFUNCTIONAL CATALYTIC COMPOSITION FOR THE HIDROTRATION OF HEAVY RAWS. DESCRIPTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a catalytic composition for the hydrotreatment process of heavy crudes. The catalyst object of the present invention consists basically of active metals and promoters whose elements belong to groups IVB, VIB and VIII, of the periodic table; It has specific properties designed to simultaneously carry out the reactions of hydrodemetalization, hydrodesulfurization, hydrodesnitrogenation and hydrodisintegration of heavy crude oils.

The catalysts obtained with this composition, when used in industrial hydrotreatment units, reduce the problems that may exist in the processing of heavy crudes in a refinery, and at the same time help to obtain distilled products with lower contents of polluting compounds.

BACKGROUND OF THE INVENTION Many heavy crudes (20-27 ° API) are difficult to process in most existing refineries. These heavy crudes are characterized by their high content of contaminants, such as metals (Nickel and Vanadium, mainly), sulfur, nitrogen and an abundant amount of waste products. These waste products generally also contain high contents of metals and Ramsbottom coal. Typically, these heavy crudes are accepted for processing by a limited number of refineries, and it is a fact that in most cases, due to their high viscosity, their transportation is carried out by diluting them with naphtha or lighter hydrocarbon streams, or by heating the pipe.

On the other hand, in order to safeguard the deteriorated ecological environment, industries tend to modernize and implement cleaner production systems. In the same way, the refining industry also tends to produce better quality fuels, with a minimum content of contaminants such as sulfur, nitrogen and metals. However, ever stricter ecological regulations make it necessary to have more efficient processes and catalysts capable of meeting these requirements.

Undoubtedly, there are no more efficient refining processes in the removal of pollutants than those of recycling, which apply practically to all fractions of petroleum, such as naphtha, intermediate distillates, vacuum distillates, waste, etc. The catalysts used in the hydrotreatment of these fractions have specific characteristics for the elimination of certain contaminants, for example, in the case of naphthas, the catalyst is designed to maximize the removal of sulfur, which is a poison for the catalysts used. in the reform of said naphthas; However, in the case of heavy crudes, where the simultaneous removal of several pollutants is desired in order to achieve the maximum hydrodesulfurization, hydrodesnitrogenation, hydrodemetallization and hydrodisintegration, catalysts with high activity and selectivity to these reactions are required, as well as severe operation. The process that operates with a catalyst of these characteristics is capable, in addition to the removal of these contaminants, of improving other properties of heavy crudes to increase the yield and quality of the distillates, among others.

The present invention relates to the composition of a novel multifunctional catalyst, highly active and selective for the hydrotreatment of heavy crudes, which provides high capacities of hydrodemetallization, hydrodesulfurization, hydrodedesitrogenation and hydrodegradation. The invention also relates to process conditions for industrial scale application.

The activity and selectivity of the catalyst are determined by various factors that influence the hydrotreatment of heavy crudes, such as: the nature and properties of the support, the catalytic agents, the promoters of activity and selectivity, the method of preparation and the activation of the same.

The catalysts that are currently used for hydrotreatment processes of petroleum fractions involving hydrodesulfurization, hydrodesnitrogenation, hydrodemetallization and hydrodegradation reactions, are constituted by metals of groups VIB and VIII of the periodic table, supported by metal oxides such as alumina, silica or silica alumina, sometimes containing secondary promoters or additives such as halogens, titanium, phosphorus, boron, etc., which improve their catalytic properties, mainly due to their dispersing effects or modifiers of the active phase or physical properties and chemical support.

The properties of the support play an important role in the catalytic activity, at first its function was only to support or contain the catalytically active agents, however, since the seventies it was deepened in the study of the properties and effects of the support , which can be designed for specific uses. The support is generally a porous solid constituted by oxides like alumina in gamma phase, delta, etc., silica, silica-alumina, titania or titania-alumina, among others. In addition, the supports can have various geometric shapes such as cylindrical, trilobal or tetralobular extrudates, spheres, pellets, etc. and varied dimensions ranging from nominal sizes of 1/32 to 1/8 of an inch in the case of hydrotreating catalysts.

The design of the supported catalysts involves the control of the properties of the active components, as well as those of the support. The need to control the properties of the support leads to different preparation methods. The best known are the sol-gel method and the coprecipitation method, originating different activity and selectivity. The impregnation of the support is carried out with a solution or solutions containing the active metals and / or additives; in this case, the solutions are required to be stable in order to avoid precipitation during impregnation and within the pores of the support, to allow the elements contained in the solution to be adsorbed and selectively distributed on the internal and external surface and avoid its agglomeration. As references of patents that relate to these methods of preparation are the following: US Pat. No. 3,989,645 of November 2, 1976, refers to the invention of two catalysts, for use in the hydroconversion of the 1050 ° F + (565 ° C +) fraction of heavy crudes or residues. These catalysts include metals of groups VIB and HIV and a metal of the group IVA, preferably germanium. One of the catalysts has a high percentage of pores with a size between 100 and 275 Á, BET surface area between 250 and 350 m / g and pore volume between 1.1 and 2.3 cc / g and is used in a first stage for the conversion and deminetalization of heavy crudes or residues. The other catalyst, used in a second stage, contains a percentage of pores with a size between 100 and 200 A, BET surface area between 250 and 350 m2 / g and pore volume between 0.9 and 1.3 cc / g, which is used for the effluent processing of the first stage of the process. The catalysts are prepared from a sol synthesis in aqueous phase or alcohol.

U.S. Patent 4,520,128 of May 28, 1985, protects a catalyst having a high metal holding capacity and good stability for the demetalization of heavy crudes prepared from a co-impregnation of aqueous solutions, which contain an agent of group VIB of the active periodic table for hydrogenation, at least one metallic component of group VIII of the same table and phosphoric oxide in solution. This process is followed by drying and calcining to obtain the final catalyst in its oxidized state. In the North American patent US 4,554,263 of November 19, 1985, the invention of a catalyst for the hydrotreatment of heavy oils is described, including as a typical application examples a blunt crude oil and a vacuum residue. The catalyst of this invention is prepared using the same materials as those employed in typical hydrotreating catalysts. In the case of conventional catalysts, the support is a mixture of an amorphous inorganic oxide, such as alumina, silica-alumina or silica-magnesia with zeolite. For this invention, it is convenient to use of alumina or an amorphous inorganic oxide, such that the mixture preferably contains between 30 and 70% by weight of zeolite. This is mixed in an aqueous solution of sulfuric acid or in an aqueous solution of sulphate. The concentration of this aqueous solution must be such that the range of sulfate anions contained in the fine composition! of the catalyst is preferably between 3 and 10% by weight. Subsequently, the catalyst is impregnated with one or more metals of groups VIA and VIII of the periodic table.

In US patent 4,613,427 of September 23, 1986 a catalyst for use in hydrodemetalization (HDM) and hydroconversion (HC) of heavy crudes and residues, and in particular a method of preparing a catalyst based on natural clays is described. The catalyst of this invention is free of hydrogenating metals of groups VI B and VIII of the periodic table and comprises mainly iron, silica and alumina derived from the composition of natural clays. The catalyst has a surface area between 20 and 100 m2 / g, a total pore volume of 0.20 to 0.90 cc / g, where 50 to 100% of the total pore volume comprises pores with a larger diameter than 400 A. The preparation method consists of the grinding and grinding of the natural clay to particles of a mesh size between 20 to 400, followed by an acidic leaching process, a washing of the clay, drying, mixed with forming substances of pore, and finally the extrusion of clay paste and calcination.

U.S. Patent 5,336,654 of August 9, 1994 protects a method for the preparation of hydrotreating catalysts for the Removal of heteroatoms, mainly petroleum sulfur. This method comprises an impregnation of an inorganic material or support in its oxide phase with a metal salt of group VIII of the periodic table and a heteropolyacid of group VI of the same periodic table, wherein the acidity of the salt of group VIII is lower tthat of group VI heteropoly acid. Subsequently the impregnated support is subjected to a heating where all the free water is removed from the support at a temperature less tor equal to 180 ° C and a pressure of 400 mm of mercury, followed by a sulfhydration of the support.

Another series of patents involving the processing of heavy fractions and heteroatoms and comprising removals of contaminants such as nickel, vanadium, sulfur and nitrogen are the following: US Pat. No. 3,966,644 of June 29, 1976 describes the preparation of particles catalytic with different particle size and porous characteristics for the hydrotreatment of petroleum residues. In this patent the reference catalysts are generally spherical or cylindrical and with characteristics of size and shape that provide a desirable activity for the hydrotreatment of heavy fractions of petroleum. The preparation of these catalyst particles involves, in a first stage, a conventional precipitation process for preparing the alumina, subsequently filtering and finally washing and adjusting the desired composition. The preparation of the catalyst form is carried out by means of a centrifugal dryer or extruder. In this second stage, the promoter metals of the catalytic activity are incorporated. Finally the particles are calcined by the conventional procedure. In addition to the extrusion, the particles can be prepared by other methods to give a certain shape such as pelletizing, molding, etc.

An effective catalyst for the hydrotreatment of asphaltene-containing hydrocarbons, especially for the decomposition and conversion thereof and the removal of metals and sulfur, is presented in US Patent 4,422,960 of December 27, 1983. The fillers of this invention involve heavy crudes and Vacuum and atmospheric waste. The invention involves a catalyst containing at least one metal selected from the groups VB, VIB, VIII and IB, whose support is composed of one or more inorganic oxides of an element of groups II, III and IV of the periodic table. The catalyst of this reference contains from 1 to 30% by weight of metal with the following textural characteristics: pores with a diameter of 75 A or more, average pore diameter in a range of 180 to 500 A, pore volume of 0.2 cc / g for a minimum pore diameter of 1500 Á.

The US patent 4,886,594 of December 12, 1989 presents the preparation of a catalyst which is formulated of a hydrogenating agent, as is the case of a metal of group VIB of the periodic table and a phosphorus component, deposited on the surface of a support of an inorganic refractory oxide and free of zeolitic components. The catalyst is applied mainly for the hydrodesnitrogenation and hydrodemetalization of charges with high sulfur content.

U.S. Patent No. 5,086,027 of February 4, 1992, describes the invention of a catalyst with a content of platinum or palladium (noble metal) in the range of 0.005 to 5% by weight for the removal of heteroatoms from synthetic fuels, in addition to a wide variety of loads that include fractions of hydrocarbons as residuals and distillates. The reference catalyst is prepared by at least one metal of group VIII in a concentration of 0.5 to 5% by weight and 3 to 18% by weight of a metal of group VI, preferably molybdenum (Mo), supported on a refractory material . The noble metal is incorporated into the refractory support using a precursor represented by ML2, where the noble metal (M) is Platinum or Palladium and ML3, where M is Ruthenium or Iridium, and L is an organic group with a sufficient number of carbon atoms. carbon (24 to 30 atoms).

In the patent US 5,468,709 of November 21, 1995, the preparation of catalysts for the hydrodesulphurisation and hydrodenitrogenation of oils (vacuum gas oil or primary light gas oil) coming from a Kuwati crude, which has a high catalytic activity, is presented. These catalysts are normally prepared by means of the following synthesis steps: formation of alumina hydrates; gamma alumina sintering; impregnation of active metals through the use of aqueous solutions of cobalt, nickel, molybdenum or tungsten salts; dried at a temperature of 100 ° C and calcination between 400 and 600 ° C. For the preparation of these catalytic species is used also an agent (alcohol or ether) with a content of carbon atoms per molecule between 2 and 10.

The present invention relates to a composition of a catalyst with excellent activity and catalytic selectivity for hydrodemetalization, hydrodesulfurization, hydrodesnitrogenation and hydrodisintegration of heavy crudes. The impregnation of the support of said catalyst is carried out by means of a solution containing the metals of groups VIB and VIII of the periodic table. This support is prepared from a boehmite modified with titania. After the impregnation step, the material is thermally treated in an oxidizing atmosphere for calcination.

Once the catalyst is obtained, the activation is carried out by means of a sulfurization process, using readily decomposable sulfur compounds such as carbon disulfide (CS2), di-methylsulfide (DMDS), dimethylsulfide (DMS), n-butyl mercaptan and other sulfhydrant agents, in order to generate the corresponding metal sulfides.

It is therefore an object of this invention to provide a multifunctional catalyst composition for the hydrotreating of heavy crudes, preferably for the hydrodemetallisation, hydrodesulfurization, hydrodesntrogenation and hydrodegradation reactions.

Another object is the obtaining of a catalyst with specific physical, chemical and textural properties for the hydrotreatment of heavy crude with gravity in a range of 20 to 27 ° API.

A third object of the present invention is that the catalyst has a good activity for the removal of metals in heavy crudes, preferably nickel and vanadium.

An additional object is that the catalyst possesses an excellent activity for the removal of sulfur in heavy crudes.

A fifth object of the present invention is that the catalyst possesses a good activity for the hydrodisintegration of heavy crudes.

Finally, another object of the present invention is to describe the process and the operating conditions to which the catalyst for the hydrotreatment of heavy crudes operates has an effective operation.

DETAILED DESCRIPTION OF THE INVENTION The design of the supported catalysts involves the control of the properties of the active components, as well as those of the support. These materials are porous and highly adsorptive, and their performance is strongly influenced by the method of preparation, so the size and the distribution of the pores that provide different activity and selectivity.

The metals are dispersed on the surface of the porous support by means of a solution or solutions containing the active metals and / or promoters. The purpose of the synthesis of the co-impregnant solution is to promote the dispersion and ease of sulfurization of the metallic agents in order to favor the activity and selectivity of the hydrodemetalization reactions, HDS, HDN and selective hydrodisintegration to liquid fractions of higher value hydrocarbons. commercial.

In particular, the catalysts described in the present invention are capable of hydrotreating heavy crudes, the hydrotreatment being understood as the performance of the hydrodemetalization, hydrodesulphurisation, hydrodenitrogenation and hydrodegradation reactions. The catalysts are constituted by a support and metals that give them physical, chemical and textural properties to carry out said reactions to industrial hydrotreatment conditions.

The supports of the catalysts of the present invention are composed of a refractory oxide, mainly of alumina, titania or their mixtures, with alumina being preferred in its gamma phase. The support also has specific textural properties of pore volume, surface area and pore volume distribution. The recommended pore volume of these catalysts should be between 0.35 and 0.8 cc / g, preferably between 0.40 and 0.7 cc / g. The surface area will be between the values of 150 and 320 m2 / g, preferably between 180 and 300 cm2 / g. With regard to the distribution of pore volume, volumes are recommended whose distribution comprises 5 to 25% of the total pores that are less than 50 A, preferably between 6 and 20% comprised in that pore size; from 10 to 40% of the pores from 50 to 200 A, preferably from 20 to 40%; from 1 to 15% of the pores from 200 to 500 A, preferably from 2 to 10%; and from 1 to 5% of the pores greater than 500 A, preferably from 1 to 2%. The average diameter resulting from this distribution is between 40 and 120 A, preferably having a value between 60 and 100 A.

On the other hand, the additive that contains the support generates greater resistance to poisoning by metals and coal, promoting a greater stability of the catalyst in long periods of operation. The basic functions of the additive are to disperse and evenly distribute the active metals responsible for promoting the reactions of hydrodemetalization, hydrodesulfurization, hydrodesnitrogenation and hydrodisintegration of the crude. The additives used are metals that belong to group IVB of the table Periodic, such as titanium and zirconium, titanium being preferred, which can be found in oxidized form as titania in its anatase or rutile phases. The titanium of the present invention can be incorporated into the support by coprecipitation or co-deposition of a titanium compound.

The support can be extruded in various geometric shapes: spherical, cylindrical or with two or more lobes, with nominal sizes ranging from 1/32 to 1/4 of an inch, preferably nominal sizes of 1/32 to 1/8 of an inch.

The integration of the active metals of the present invention is carried out by means of impregnation in an aqueous solution. The aqueous solution is prepared in basic or acid medium. The basic solution is prepared with a pH of 7.5 to 12, preferably from 8 to 11 from salts containing the metals of group VIII, preferably Ni, as well as salts containing the metals of group VIB, preferably Mo. The salts of the metals of group VIII used may be nickel acetate, nickel nitrate, nickel carbonate hydroxide, etc., preferably nickel hydroxide carbonate. The salts used containing the VIB group metals are: ammonium heptamolybdate, molybdic acid, molybdenum trioxide, etc., preferably molybdenum trioxide.

The solution in an acid medium is prepared at a pH of 1 to 6.5, preferably 1 to 3, from salts containing the metals of the group VIII, preferably Ni, as well as compounds containing elements of group VIB, such as Mo and W, preferably Mo. The salts of the metals of the HIV group used can be nickel nitrate, nickel acetate, etc., with nickel nitrate being preferred. . The metal compounds of group VIB used are: ammonium molybdate, molybdic acid, molybdenum trioxide, etc., with molybdenum trioxide being preferred.

Stabilizing agents can be used in both the basic solutions and in the acids. For solutions in acid medium, these can be nitric acid, phosphoric acid, hydrogen peroxide, etc., in concentrations such as to maintain the pH of the solution in the range of 1 to 3, preferably the phosphoric acid is selected to provide the metal oxide of phosphorus (phosphorus pentoxide).

Also, individual solutions can be prepared from each nickel and molybdenum compound and successive impregnations, each followed by a heat treatment comprising a drying of 100 to 120 ° C and a calcinated of 450 to 550 ° C. Impregnation with a solution containing all the desired active metals is preferred. The impregnation can be carried out by various methods such as: immersion of the support in the solution, incipient wet and by dripping or spraying, preferably spraying.

The impregnated material before drying is kept aged for 3 to 20 hours at room temperature, preferably 10 to 15 hours. hours, to ensure a perfect distribution of the solution in the porosity of the support.

Subsequently, the impregnated material is subjected to a drying at a temperature range of 100 to 120 ° C, for a period of time of 4 hours.

Finally, once the impregnated material is dry, it is subjected to calcination in an oxidizing atmosphere at a temperature between 450 and 500 ° C for a period of time of 2 to 10 hours, preferably 3 to 5 hours.

The resulting catalysts contain elements that are related as follows: an atomic ratio of TiO2 / (MoO3 + NiO) from 0.3 to 0.6, preferably from 0.3 to 0.5, the concentrations of MoO3 range from 10 to 30% by weight, preferably between 10 and 20% by weight, the NiO concentrations range from 2 to 8% by weight, preferably from 2.5 to 6% by weight and the P2O5 concentrations from 3 to 7% by weight, preferably from 4 to 5% by weight. Within the textural properties of this catalyst, there is a surface area of 150 to 320 m2 / g, preferably 180 to 300 m2 / g, pore volume of 0.35 to 0.8 cc / g, preferably 0.40 to 0.7 cc / g an average pore diameter of 40 to 120 A, preferably 60 to 100 A.

Before using the catalysts obtained in the present invention, these must be activated by converting the metal oxides to sulphides, by means of a sulfhydration, using the same filler or sulfurizing agents such as carbon disulfide (CS2), dimethyldisulfide (DMDS), dimethylsulfide (DMS), n-butyl mercaptan, etc., at industrial operating conditions.

The processed catalysts can be used in conventional fixed bed hydrotreating reactors to process heavy crudes with a density range of 20 to 27 ° API, having total nitrogen concentrations of 500 to 4500 ppm, of basic nitrogen of 100 to 1000 ppm , of sulfur of 10,000 to 45,000 ppm and of metals (Ni + V) of 100 to 800 ppm.

The operating conditions to which the fillers can be subjected to hydrotreat with the catalysts of the present invention are the following: reaction temperature of 300 to 450 ° C, velocity spaces of 0.1 to 4.0 hr "1, pressures of 50 to 150 Kg / cm2 and hydrogen / hydrocarbon ratios from 1000 to 10,000 cubic feet per barrel of cargo (ft3 / bbl).

To compare the catalytic activity of the catalysts prepared with the composition of the present invention, the percentages of hydrodemetallization, hydrodesulfurization, hydrodesitrogenation and hydrodegradation obtained in the hydrotreatment of a heavy crude were determined.

EXAMPLES Below are some examples that support what is described in the present invention, which do not limit the scope thereof. In the examples 1 and 2 catalysts are used with the typical supports of alumina and silica-alumina respectively, which were taken as a basis of comparison, while in the examples 3 and 4 are described catalysts with support of alumina modified with titania with contents of the latter of 3.8 and 9.35% in weight respectively.

EXAMPLE 1 The support used for the preparation of one of the heavy crude hydrotreating catalysts was prepared using a boehmite with the following characteristics: surface area of 216 m / g, pore volume of 0.37 cc / g, a pore distribution of the following form: 24.3% of the total pores with a size smaller than 50 A, 38.7% of the pores in a range of 50 to 100 A, 20.4% in a range of 100 to 200 A, 11.7% with a size between 200 and 500 A and 4.9% of the total pores for sizes greater than 500 Á, as well as a particle size in a range of 40 to 80 microns. A part of the boehmite of the present example is peptized and then mixed with the rest thereof, until obtaining an extrudable paste. After extruded, the support with a shape defined (cylindrical, trilobal, etc.), dried for 4 to 8 hours at a temperature between 100 and 120 ° C and calcined in an oxidizing atmosphere at a temperature between 500 and 550 ° C for 3 to 5 hours. The prototype I support is basically composed of alumina in its gamma phase. This support was impregnated with an aqueous solution containing the metals of group VA, VIB and VIII of the periodic table. The impregnating solution was prepared starting from 15.0 g of molybdenum trioxide, 10.8 g of nickel acetate and 4.4 ml of phosphoric acid, which was impregnated to the support by means of the spraying technique. The impregnated material was kept at rest at room temperature, preferably for a period of 10 to 15 hours. Subsequently, the impregnated material was subjected to a drying between 80 and 120 ° C, preferably between 90 and 110 ° C, for a time interval of 4 to 8 hours, and finally this material was subjected to a calcination at a temperature between 450 and 500 ° C under an oxidizing atmosphere for 3 to 6 hours. The obtained catalyst (Prototype I) was characterized and its properties are shown in table 1.

EXAMPLE 2 For the preparation of the prototype II support, a modified boehmite with a content of 5.1% by weight of silica (SiO2) was used, which was prepared using a conventional co-deposition or co-deposition procedure. A part of the boehmite used in example 1 is peptized and then mixed with the boehmite modified with silica, until obtaining an extrudable paste. After extruded, the support with a defined shape (cylindrical, trilobal, etc.), was dried for 4 to 8 hours at a temperature between 100 and 120 ° C and calcined in an oxidizing atmosphere at a temperature between 500 and 550 ° C. The prototype II support is basically composed of alumina and silica. This support was impregnated with an aqueous solution containing the metals of group VA, VIB and VIII of the periodic table, with the same procedure of example 1. The impregnated material was kept at rest at room temperature, preferably between 10 and 15 hours. Subsequently, the impregnated material was subjected to a drying between 80 and 120 ° C, preferably between 90 and 110 ° C, for a time interval of 4 to 8 hours, and finally it was subjected to a calcination at a temperature between 450 and 500 ° C under an oxidizing atmosphere. The obtained catalyst (Prototype II) was characterized and its properties are shown in table 1.

EXAMPLE 3 The support for the preparation of the prototype III was obtained using a titania-modified boehmite with a content of 3.8% by weight, which was prepared using a conventional co-deposition or co-precipitation procedure similar to that of example 2. For the preparation of the support it was also used a part of the boehmite used in Example 1, was peptized and subsequently mixed with the modified boehmite with titania. The support was extruded, dried and calcined in the same way as in the previous examples. The integration of the metals of groups VA, VIB and VIII of the periodic table is performed with the same methodology as that mentioned in examples 1 and 2. Subsequently drying and calcination were carried out at the same temperature conditions as in the preparations of prototypes I and II. The obtained catalyst (Prototype III) was characterized and its properties are shown in table 2.

EXAMPLE 4 The support for the preparation of the prototype IV was obtained with the same preparation procedure as the previous examples. For the preparation of the support, a part of the boehmite used in Example 1 was peptized and subsequently mixed with the modified boehmite with titania with a content of 9.35% by weight. The support was extruded, dried and calcined also in the same way as in the previous examples. Subsequently, the support was impregnated with an aqueous solution containing the metals of groups VIB and VIII of the periodic table. The impregnating solution was prepared starting from 17.3 g of molybdenum trioxide and 5.8 g of nickel carbonate hydroxide, which was impregnated to the support by means of the spraying technique. The impregnated material was kept at rest at room temperature, preferably between 10 and 15 hours. Afterwards it was dried and calcinated at the same temperature conditions as in the preparations of prototypes I, II and III. The obtained catalyst (Prototype IV) was characterized and its properties are shown in table 2.

In order to determine the catalytic activity of the synthesized prototypes of examples 1, 2, 3 and 4, these were evaluated at the pilot plant level by hydrotreating a heavy crude. The complete characterization of the load used is detailed in table 3.

Each elaborated prototype was loaded in the intermediate zone of an isothermal reactor and subsequently subjected to a drying step between 80 and 120 ° C. The catalytic bed was preheated to a temperature of 230 ° C, where the activation of the metal oxides began by a sulfhydration step, which consisted in passing through the catalyst a mixture of hydrogen and a stream with 0.60% by weight of sulfur , composed of sweet gasoline and a presulfhydrant agent. The operating conditions of the activation stage were: hydrogen / hydrocarbon ratio from 2000 to 3500 standard cubic feet per barrel, space velocity from 1.0 to 3.0 h "1, a pressure of 15 to 54 kg / cm2 and activation time between 12 and 18 hours, to ensure the conversion of the metal oxides of the groups VA, VIB and VIII of which the catalyst of examples 1, 2 and 3 is composed, to their corresponding metal sulphides and of the conversion of the metal oxides of groups VA, VIB and VIII of which the catalyst of examples 1, 2 and 3 is composed.

Once the prototypes were sulfided, the flow of naphtha was suspended and the flow of heavy crude oil was started at the following operating conditions: temperature of 380 to 420 ° C, pressure of 70 to 100 Kg / cm2, space velocity of 0. 5 to 2.0 hr "1, hydrogen / hydrocarbon ratio of 5,000 to 10,000 standard cubic feet per barrel, and a test duration of 60 to 231 hours.

The products recovered from the evaluations of the prototypes were characterized physically and chemically to know the content of total sulfur, total nitrogen and metals (Ni + V), to determine the percentages of hydrodesulfurization (HDS), hydrodesnitrogenation (HDN) and hydrodemetalisation (HDM) ), respectively. In addition to the products, their TBP distillation was determined to evaluate the percentage of hydrodisintegration (HDC), which was evaluated as follows: % HDC = ™? Z ™ p * 100 Where: RVC =% volume of vacuum residue of the load RVP =% volume of residue of Vacuum of the product The results of these evaluations are shown in Table 4, observing that the prototypes III and IV elaborated from the boehmite modified with titania with contents of 3.8 and 9.35% by weight respectively, according to the present invention, significantly surpass the activity of the prototypes I and II, which were elaborated using only boehmite in the prototype I and this same boehmite mixed with boehmite modified with silica in prototype II. As a result of this, a lower content of contaminants was obtained in the hydrotreated products using the prototypes modified with titania, prepared according to the present invention. or. PROPERTIES OF THE PROTOTYPES OF EXAMPLES 1 and 2 TABLE No. 2 PROPERTIES OF THE PROTOTYPES OF EXAMPLES 3 and 4 TABLE No. 3 CHARACTERIZATION OF THE LOAD USED IN THE EVALUATION OF THE PROTOTYPE OF EXAMPLES 1, 2, 3 and 4 TABLE No. 4 RESULTS OF THE EVALUATION OF PROTOTYPES I, II, AND IV IN THE HIDROTRATION OF HEAVY RAW

Claims (1)

NOVELTY OF THE INVENTION Having described the present invention, this is considered as a novelty and therefore, the content of the following clauses is claimed as property:

1. A multifunctional catalytic composition for the hydrotreatment of heavy crudes comprising: a support based on boehmite modified with an oxide of a metal of group IVB of the periodic table, preferably titanium in a concentration of 3 to 10% weight in its phases anatase or mixture of anatase - rutile extruded cylindrical or extruded with two or more lobes, and sizes from 1/16 to 1/8 of nominal diameter, surface area between 150 and 320 m2 / g, preferably between 150 and 300 m2 / g, pore volume between 0.3 and 0.8 cc / g, average pore diameter between 40 and 100 A, pore volume distribution with a percentage of 0 to 13% of pores below 50 A, from 40 to 75% of the pores. pores between 50 and 100 A, from 10 to 45% pores between 100 and 200 A, from 1 to 10% of pores between 200 and 500 A, and from 0 to 5% of pores greater than 500 A; an oxide of a metal of group VIB of the periodic table, such as molybdenum trioxide, with a concentration between 10 and 30% by weight, preferably between 10 and 20% by weight; an oxide of a metal of group VIII of the periodic table, such as nickel oxide, with a concentration between 2 and 8% by weight, preferably between 2.5 and 6% by weight; an oxide of a metal of the group VA of the periodic table, such as phosphorus pentoxide, with a concentration between 3 to 7% by weight, preferably between 4 and 5% by weight. A multi-functional catalytic composition for the hydrotreatment of heavy crudes in accordance with clause No. 1, characterized in that it can fulfill a TiO2 / ratio (metal oxide of group VIB + metal oxide of group VIIIB) from 0.2 to 0.5. A multifunctional catalytic composition for the hydrotreatment of heavy crudes in accordance with clauses Nos. 1 and 2, characterized in that the support based on boehmite modified with a metal oxide of group IVB of the periodic table, such as titanium, is previously subjected to to a drying in a range of 4 to 8 hours at a temperature of 100 to 120 ° C and then calcined in an oxidizing atmosphere at a temperature between 500 to 550 ° C; to then impregnate it with an aqueous solution containing a single stage of impregnation with salts of the elements of groups VIB and VIII of the periodic table, preferably Mo and Ni, in acidic medium with pH of 1 to 3, using a stabilizing agent, such as, the phosphoric acid provided by phosphorus pentoxide; next, the impregnated material is dried between 80 and 120 ° C, preferably 90 and 1 10 ° C for a time interval of 4 to 8 hours and finally, it is again exposed to a calcination with a temperature between 450 to 550 ° C under an oxidizing atmosphere. A multi-functional catalytic composition for the hydrotreatment of heavy crudes in accordance with clauses Nos. 1 to 3, characterized in that it requires activation by means of a sulfhydration step, using for this activation the same load of heavy crude or a sulfhydrant agent such as: carbon disulfide (CS2), dimethyldisulfide (DMDS), dimethisulfide (DMS), n-butyl mercaptan, etc., which is diluted in a naphtha or in the same heavy oil load. A multi-functional catalytic composition for the hydrotreatment of heavy crudes in accordance with clauses No. 1 to 4, characterized in that it processes loads of heavy crudes with 20 to 27 ° API, total sulfur contents of 10,000 to 45,000 ppm, total nitrogen of 500 to 4,500 and metals (Ni + V) from 100 to 800 ppm. A multi-functional catalytic composition for the hydrotreatment of heavy crude oils according to clauses Nos. 1 to 5, characterized in that it can hydrodemetalize, hydrodesulfurize, hydrodesnitrogenate and hydrodisintegrate simultaneously with a temperature in the range of 300 to 450 ° C, space velocity of 0.1 to 4.0 h "1, pressure of 50 to 150 Kg / cm2 and a hydrogen / hydrocarbon ratio between 1, 000 to 10,000 standard cubic feet per barrel of cargo.