MXPA97006888A - Process of preparing a catalyst for the disintegration of gascopes and the catalyst results - Google Patents

Abstract

The present invention relates to: The invention that is described relates to a process for the preparation of a catalyst for the disintegration of gas oils, comprising the preparation of an activity matrix and controlled texturable properties, formulated with a hydrated alumina with porous characteristics and of particular acidity, a silica-alumina binder and a kaolinite-like clay and to which a zeolitic component of the faujasite type "Y" previously exchanged with rare earths of a particular composition is incorporated, which favors stability and selectivity of final catalyst. The properties of the matrix favor the conversion of hydrocarbon molecules present in the heavier fraction of gas oil, to entities of smaller size that can penetrate the structure of the zeolitic component for its selective transformation to hydrocarbons that fall in the boiling range of the gas. The invention also relates to the catalyst resulting from the process for its preparation

Description

f PROCESS FOR PREPARING A CATALYST FOR THE DISINTEGRATION OF FUELS AND THE RESULTING CATALYST. 5 DESCRIPTION TECHNICAL FIELD OF THE INVENTION The invention described is related to a process for the preparation of a catalyst F for the disintegration of gas oils, which comprises the preparation of a matrix of activity and controlled textural properties, formulated with a hydrated alumina of particular porous characteristics and acidity. , a silica-alumina binder and a kaolinite-type clay and to which is incorporated a zeolitic component of the faujasite type "Y" previously exchanged with rare earths of a particular composition, which favors the stability and selectivity of the final catalyst. 20 The properties of the matrix favor the conversion of hydrocarbon molecules present in the heavier fraction of gas oil to entities of smaller size that can penetrate the structure of the zeolitic component for selective transformation to hydrocarbons that fall in the boiling range. of gasoline.

The invention also relates to the catalyst resulting from the process for its preparation.

BACKGROUND OF THEINVENTION The catalysts for the disintegration of gasoils in fluidized bed, are commonly prepared by the integration of zeolites of the faujasite type "Y", in mat constituted by one or more components based on clays, being these frequently of the kaolinite, silica, silico- type. aluminates and aluminas.

Mexican patent application No. 2776 describes a process for the preparation of catalysts that promotes the disintegration of gas oils in the fluid. This procedure consists of treating a natural clay with dilute sulfuric acid; forming a gel with the resulting product and sodium silicate allowing aging for 15-60 minutes at a pH in the range of 5.5 - 6.5; faujasite addition "Y" in its sodium form; spray-drying the resulting suspension; The obtained microspheroidal product and exchange with rare earth salts.

Mexican patent application No. 56438 describes the preparation of a mat that can be used as a FCC catalyst or as an additive in combination FCC equilibrium catalyst, to disintegrate bottoms in the fluid bed catalytic disintegration units. In this application the method of preparation is claimed which consists of: the synthesis of a gel from a solution of an aluminum compound which can be gibbsite, bayerite and / or combinations thereof, and acetic acid. The resulting gel is combined with a natural clay and subjected to a drying and calcination process.

The catalytic systems to process gas oil, are constituted by two k. Main components: zeolite and matrix. They can include in their formulation materials that allow to passivate metals, reduce SOx and NOx emissions, promote the oxidation of CO or increase the disintegration of heavy fractions among others.

These additives can be integrated into the same particle or added separately.

The zeolites reported in the literature that are used in catalysts designed for their application in the disintegration of diesel, are usually "Y" Faujasites exchanged with different levels of rare earths.

Most catalysts for disintegrating diesel include in their formulation matrices with medium activity and a porous distribution such that molecules of large size of the charge have easy access to the acid sites and therefore, a greater possibility of disintegration. . In addition, the matrix must have a high susceptibility to stripping of hydrocarbons, greater resistance to metallic poisoning and selectivity to coke. The synthetic component of these matrices is generally alumina and / or silica-alumina even when it may contain components such as alumina-magnesia, silica-titania, among others. The natural component is often a natural clay of the kaolinite type.

The matrix must have an adequate pore volume to accommodate more non-vaporized hydrocarbons and more coke than a matrix with conventional pore volume. The optimal pore size reported in the literature is 2-6 times the size of the molecule to be disintegrated. The macromolecules are converted to small entities in the matrix, which can penetrate the zeolite for selective conversion to products that make up the gasolines. However, too much activity in the matrix can lead to a non-selective disintegration, so the catalyst should have an optimum zeolite / matrix activity ratio to maximize the disintegration of bottoms with a minimum loss of gasoline yield.

DETAILED DESCRIPTION OF THE INVENTION In general terms, the preparation method, which is the subject of the present invention, consists of the following main steps: In a first stage, it is prepared, by controlled neutralization of sodium silicate and aluminum salts with dilute sulfuric acid, a high area amorphous silicoaluminate which has been shown to be excellent for promoting mechanical strength in the finished catalyst. The amorphous silicoaluminate is combined in a second step with a suspension of finely dispersed kaolinite. In a third stage, the resulting material is combined with a hydrated alumina of particular textural and acidic characteristics that promotes the primary disintegration of high molecular weight hydrocarbons present in the heavy fraction of diesel and allows to reduce the effect of metal poisoning. Finally, a zeolite of the faujasite type "Y" is incorporated, an active species that allows the disintegration of heavy hydrocarbons and leads them to compounds of greater commercial value. The resulting material, after having been homogeneously dispersed, is spray dried with conventional equipment and conditions and by The latter is subjected to a washing process with ammonia solution and water and finally to a thermal treatment.

In more detail, in order to facilitate the understanding of the method of preparing the gas oil disintegration catalyst, which is the subject of the present invention, the main steps are described below. 1. Preparation of suspensions of kaolin, hydrated alumina and zeolites. The solids, separately are subjected to a first grinding process using a ball mill, for a sufficient time so that 100% of the material has a size smaller than 6-7 microns. The resulting suspension is subjected to a more severe dispersion using a ULTRATURRAX equipment at 10000 r.p.m. The average size of The recommended particle is approximately one miera. Once the recommended size has been reached, the water content is adjusted to have a suspension with a recommended solids content of 60-75% by weight, in the case of kaolin and 20-30% by weight for hydrated alumina and 30% by weight. - 40% weight for the zeolite. 2. Preparation of the binding agent. A silica or silica-alumina sol is synthesized, which will act as a binder of the active species, by direct combination of sodium silicate, containing 1.35 meq of NaOH and 0.1372 g / ml of SiO2, with a solution containing 0.05 g of measured aluminum calculated as AI2O3 and 0.848 mmol / ml of sulfuric acid in sufficient quantity to reach a pH less than or equal to 3.0. In the case of silica sol, the aluminum content is zero. 3. Preparation of catalysts. To the silica or silica-alumina sol matrix that is maintained in agitation, it is added, in this order, although it is not limiting: a suspension of alumina, kaolin and zeolite; allowing after each addition that the system is homogenized .. The solids content is adjusted to the maximum permissible concentration by the sprinkler dryer feeding system.

Drying The drying of the materials obtained at laboratory and pilot level was carried out in a Mobile Minor equipment from Niro Atomizer under the following conditions: 10 inlet temperature 350 ° C, outlet temperature 140 ° C, air pressure 0.8 Bar, charge flow 120 ml / min and concentration of solids at load 30% weight. The obtained microspheroidal product has an average particle size of 45-60 microns. 4. Washing and calcining. The washing is done with water and solution of an ammonium salt, until reaching a Na2O content in the catalyst of less than 0.40% by weight. The resulting material is dried at 110 - 120 ° C for 1 - 2 h to remove moisture.

The calcination is done in a programmable muffle with air atmosphere, following a calcination profile that includes three heating ramps to control the change of crystalline phases. The material is maintained at a temperature of 550 ° C for 2.5 h.

The determination of the textural properties of the catalysts obtained by the method described above is determined using an ASAP 2000 device from Micromeritics. The surface area is determined by applying the BET equation with relative pressures of P / Po from 0.01 to 0.05. The area of zeolite and matrix is determined according to the ASTM-D method 4365. The pore volume is determined in accordance with the method ASTM-D 4222. For the determination of structure properties A SIEMENS D-500 X-ray diffractometer with secondary beam monochromator and software for computer automation and data processing was used. The methods used are ASTM D-3942-90 for the determination of cell parameters and ASTM D-3906-85 for the determination of the crystallinity of zeolites of the Faujasite Y type. f- The evaluation of the catalytic properties of the resulting materials was carried out after deactivation at 788 ° C for 4 h with 100% steam, operating at the microreactor level in a fixed bed and in a pilot fluid-bed plant. The activities were carried out at the microreactor level in a fixed bed and the final tests in a pilot plant with a fluid bed. The microreactor test was performed under the following conditions: Weight of catalyst, 4.1 g; charging temperature, 40 ° C; reaction temperature, 520 ° C; injection time, 75 seconds; Weight of diesel, 1.3 g. The study was carried out varying the catalyst / oil ratio between 2 and 5 weight.

The catalyst resulting from the application of the process described herein The invention is mainly constituted by: a) a crystalline silicoaluminate of the zeolitic type, whose structure corresponds to the faujasite "Y" which is previously stabilized until reaching a cell size of 24.50 to 24.70 ° A. b) Metals of the lanthanide group, mainly La, Ce, Nd, Pr, among others, in a proportion of 8 to 10 parts of La2O3 for each part of CeO2. c) an alumina ^? o hydrated, which depending on the application of the catalyst can be selected from; boehmite, bayerite, gibbsite or mixture of both, c) A binder, which depending on the mechanical strength required for specific FCC industrial units, can be selected from silica for medium strength catalysts, or from silica - alumina for high mechanical strength catalysts and d) Natural or treated kaolinite thermally, as means of dispersion of the active species.

The characteristics of the obtained catalysts will be based on the industrial application that is intended to give (processing light, heavy loads, obtaining gasoline, olefins, etc.). However, the main control parameters in these catalysts move within the following ranges: zeolite content of 20 to 40% weight, preferably 28 to 34% weight; hydrated alumina of 5 to 20% weight, preferably 8 to 15% weight; rare earths of 0.5 to 4% weight, preferably 1.5 to 3.5% weight; alumina of 30 to 55% weight; Sodium oxide 0.2 to 0.4% weight; density from 0.7 to 0.9 g / cc; pore volume from 0.15 to 0.18 cc / g.

EXAMPLES According to the procedure, object of the present invention, a series of examples that allow obtaining catalysts for the disintegration of gas oil are described below, these practical examples do not limit the scope of the present invention and represent the best method known by the applicant, to carry out the present invention.

EXAMPLE No. 1.

In a reactor equipped with a device for vigorous stirring, 132.6 ml of sodium silicate solution are added, containing: 1.35 meq of NaOH / ml 0.1372 g of SiO2 / ml of solution and 88.95 ml of a solution containing: 0.8479 mmol / ml of H2SO4, 0.04838 g / ml of AI2O4. The resulting sol is preferably stirred for a period of 0 to 15 minutes. 136.5 g of a suspension of a natural clay (52% weight of silica, 43% weight of alumina and 2.5% weight of TiO2) are gradually added to 56% solids, preferably with pH previously adjusted to 4.0 with sulfuric acid. 192 g of suspension with 27.5% solids, of a zeolite of the faujasite type REUSY, previously exchanged with rare earths in sufficient quantity to have a 3.6% weight content in the final catalyst. Preferably the pH is adjusted to 4 using a dilute solution of sulfuric acid. The resulting sol is stirred, preferably, for a period of 0 to 15 minutes. 89.92 g of hydrated alumina suspension are added, with 21.6% weight of solids, preferably with pH adjusted to 3. This alumina, after having been calcined at 650 ° C for 2 hours in air atmosphere, has an area of 276 m2 / g, pore volume of 0.33 cm3 / g, average pore diameter of 50 A, total acidity of 1570 micro mol / g measured by the chemisorption of pyridine and a monomodal pore size distribution between 20 and 70 A. The resulting sol is stirred, preferably for a period of 0 to 15 minutes. After adjusting the solids content, the material is dried in a spray dryer under the following conditions: inlet temperature of 350 ° C, outlet temperature 140 ° C, air pressure 0.8 bar, load flow 120 ml / min and concentration of ^ 15 solids in load 30% weight. Wash and ion exchange treatments were carried out to minimize the sodium content, for this, 100 g of the obtained microspheroidal product with an average particle size of 45-60 microns is suspended in 200 g of water and reacted with 200 g. of 54% weight NH4CI solution at a temperature of 70 ° C for 30 minutes. The resulting material is washed with sufficient water to remove chlorides, dried and the exchange and washing process repeated. The material is calcined at 550 ° C, 1 h, the exchange and washing process is repeated twice and finally the final material is dried and calcined. The resulting surface area of the catalyst is 247 m2 / g, micropore area of 200 m2 / g, matrix area of 47 m2 / g and pore volume of 0.17 cprVg.

EXAMPLE No. 2.

The preparation of a silicoaluminate that will function as the catalyst matrix is carried out by means of the controlled neutralization of 378 ml of a sodium silicate solution containing 1.35 eq of NaOH and 137.2 g of SiO2 per liter of solution with 253 ml of a solution containing: 0.8479 mol / l of H2SO4, 48.38 g / l of AI2O4. The resulting sol is maintained in constant agitation, until complete homogenization, preferably, without suspending the agitation until concluding with the preparation of the catalytic material. 390 g of suspension is added gradually to 56% solids of a kaolinite-type clay, preferably with pH previously adjusted to 4.0 with diluted sulfuric acid solution, 550 g of suspension with 27.5% solids, of a zeolite of the type of ultra-stable faujasite of cell size of 24.64 A and a surface area of 604 m2 / g, previously exchanged with rare earths in sufficient quantity to have a content of 3.6% weight in the final catalyst. Preferably the pH is adjusted to 4 using a dilute solution of sulfuric acid. 112 g of suspension of a boehmite, with 21.6% weight of solids, are added. The boehmite was previously reacted with dilute sulfuric acid in sufficient quantity to reach a pH of 3.0, for a time of 10 minutes. The resulting material is maintained, preferably with agitation after adjusting the solids content in the suspension, the material is dried in a spray dryer to the conditions mentioned in example No. 1. Wash and ion exchange treatments were carried out to reduce the minimum sodium content; for this 2 is used * g of water and 2 g of solution of NH4CI at 54% weight for each g of the microspheroidal product. The resulting material is washed with sufficient water to remove chlorides, dried and the exchange and washing process repeated. The material is calcined at 550 ° C, for 1 h. The exchange and washing process is repeated twice and finally dried and calcined. The resulting surface area of the catalyst is 234 m2 / g, micropore area of 201 m2 / g, matrix area of 33 m2 / g and pore volume of ~ 15 0.16 cm3 / g. The obtained microspheroidal product has an average particle size of 45-60 microns.

EXAMPLE No. 3.

A catalyst is prepared according to example No. 2, in which the zeolite used is replaced by one containing composition: alumina of 20% by weight, silica by 68% by weight, Na2O, 4.1% by weight and a content of earths rare enough to have a 2.1% weight content in the final catalyst. The network parameter of this zeolite is 24.60 ° A and its area is 640 m2 / g. The content of boehmite present in the catalyst matrix has also been modified. The final composition of the dry base catalyst at 550 ° C is: Zeolite 30% weight, boehmite 10% weight, kaolin 45% weight and 15% weight of binder. The resulting surface area of the catalyst is 234 m2 / g, micropore area of 201 m2 / g, matrix area of 33 m2 / g and pore volume of 0.16.

F cm3 / g. The resulting surface area of the catalyst is 299 m2 / g, micropore area of 204 m2 / g, matrix area of 95 m2 / g and pore volume of 0.25 cm3g.

EXAMPLE No. 4.

In this example, the preparation of a catalyst according to the method described in Example No. 1 is described, with the exception that an ultrastable zeolite with a cell parameter of 24.57 ° A and a surface area of 597 m2 / is used. g. The zeolite used contains 22.2% by weight of AI2O3, 75% of SiO2, 4.0% by weight of Na2O and 4.0% by weight of rare earths. The final catalyst has a total of active species (zeolite + alumina) of 40% weight, zeolite / matrix ratio of 3.0 and a rare earth content is 1.2% weight, the surface area is 320 m2 / g, the zeolite area is 205 m2 / g , the matrix area of 117 m2 / g and the pore volume of 0.2064 cm3g.

EXAMPLE No. 5.

Same as Example 4 with the difference that the content of zeolite was increased and the content of the natural clay decreased. The final catalyst has a total of active species (zeolite + alumina) of 45% weight, zeolite / matrix ratio of 3.5 and a rare earth content of 1.4% weight. The total area of this catalyst is 357 or m2 / g, micropore area of 259 m2 / g and pore volume of 0.31 cm3 / g.

EXAMPLE No. 6.

A catalyst is prepared according to example No. 2, in which the matrix is formulated with a 1/1 mixture of aluminas in its boehmite / bayerite phase, composition allows to obtain a bimodal porous distribution. The final catalyst has a zeolite concentration of 30% by weight, 43% by weight of zeolite + alumina active materials and 45% by weight of natural clay. The total area is 260 m2 / g, matrix area of 82 m2 / g and the content of rare earths is 2.2% weight. 20 EXAMPLE No. 7.

A catalyst is prepared according to Example No. 3, with the difference that the zeolite content is 31% by weight, 12% by weight of an active alumina is included. which, after having been calcined at 650 ° C for 2 h in an atmosphere of air, has the following properties: total area of 260 m2 / g, pore volume of 0.458 cm3 / g, total acidity measured by pyridine adsorption of 1350 micromol / g and total acidity measured by NH3 adsorption of 620 micromol / g. The main characteristics of the catalyst are: Zeolite + active matrix of 43% weight, zeolite / active matrix of 2.6, total area of 243 m2 / g, zeolite area of 164 m2 / g, matrix area of 73 f-m2 / g average BJH pore diameter of 57 ° A. 10 EXAMPLE No. 8.

A catalyst according to Example No. 7 is prepared, except that the content of kaolin used in the preparation of the catalyst is 34% by weight, the content of active alumina is 17% by weight, the zeolite / alumina ratio is 1.8 and the amount of zeolite + active alumina is 48% weight. The characteristics of the resulting catalyst are: Total area of 206 m2 / g, zeolite area of 116 m2 / g, matrix area of 90 m2 / g.

EXAMPLE No. 9.

A catalyst is prepared according to Example No. 7, except that the content of kaolin used in the preparation of the catalyst is 44% by weight, the content of active alumina is 7% by weight, the zeolite / alumina ratio is 4.4 and the amount of active zeolite + alumina is 38% by weight. The characteristics of the resulting catalyst 5 are: Total area of 140 m2 / g, zeolite area of 77 m2 / g, matrix area of 63 m2 / g and pore volume of 0.2174 cm3 / g.

EXAMPLE No. 10.

A catalyst is prepared according to example No. 3, with the difference that in the binder preparation an acid solution was used that does not include AI2O3, the zeolite content was 31% weight, including 12% weight of a active alumina, which after having been calcined at 650 ° C for 2 h in an air atmosphere, presented the following properties: total area of 297 m2 / g, volume of 15 pores of 0.686 crrrVg, total measured acidity by adsorption of pyridine of 1340 micromol / g and total acidity measured with NH3 of 550 micromol / g. The main characteristics of the catalyst are: Zeolite + active matrix of 43% weight, zeolite / active matrix of 2.6, total area of 301 m2 / g, zeolite area of 219 m2 / g, matrix area of 82 m2 / g, volume of pore of 0.3747 crrrVg and average pore diameter of 105 ° A. EXAMPLE No. 11.

A catalyst is prepared according to example No. 7, with the difference that: in the binder preparation an acid solution was used which does not include AI2O3 the active alumina which is used, after having been calcined at 650 ° C for 2 h in an atmosphere of air, the properties that are mentioned below: total area of 237 m2 / g, pore volume of 1,092 cm3 / g, BET pore size of 177 ° A, total acidity measured by pyridine of 1180 micromol / g and total acidity measured with NH3 of 450 micro mol / g. The main characteristics of the catalyst are: total area of 311 m2 / g, zeolite area of 230 m2 / g, matrix area of 81 m2 / g, pore volume of 0.395 and diameter 10 average BJH pore of 115 ° A.

EXAMPLE No. 12.

A catalyst according to Example No. 11 is prepared, with the difference that the active alumina which is used has, after being calcined at 650 ° C for 2 h in an atmosphere of air, the properties which are then mention: total area of 53 m2 / g, pore volume of 0.336 crrrYg, BET pore size of 138 ° A, total acidity measured by pyridine adsorption of 357 micromol / g and total acidity measured by adsorption of NH3 to 126 micro mol / g. The main characteristics of the catalyst 20 are: total area of 269 m2 / g, zeolite area of 217 m2 / g, matrix area of 52 m2 / g, pore volume of 0.297 crrrVg and average BJH pore diameter of 132 ° A .

F 5 EXAMPLE No. 13.

A catalyst is prepared according to example No. 11, with the difference that the active alumina which is used has, after having been calcined at 650 ° C for 2 h in an atmosphere of air, the properties mentioned below. Total area of 68 m2 / g, pore volume of 0.605 cm3 / g, BET pore size of 254 ° A, total acidity measured by pyridine adsorption of 390 micromol / g and total acidity measured by f ^ SF1 ^ adsorption of NH3 at a temperature of 200 ° C, of 250 micromol / g. The main characteristics of the catalyst are: total area of 290 m2 / g, zeolite area of 235 m2 / g, matrix area of 55 m2 / g, pore volume of 0.354 cm3 / g and average pore diameter BJH of 152 ° A.

EXAMPLE No. 14.

A catalyst is prepared according to example No. 11, with the difference that the The active alumina that has been used, after having been calcined at 650 ° C for 2 h, in an atmosphere of air, has the following properties: total area of 186 m2 / g, pore volume of 0.519 cnrrVg, size of BET pore of 111 ° A, total acidity measured by pyridine adsorption of 2699 micromol / g and total acidity measured with NH3 of 650 micro mol / g. The main characteristics of the catalyst are: total area 25 of 303 m2 / g, zeolite area of 228 m2 / g, matrix area of 75 m2 / g, pore volume of 0.356 and average BJH pore diameter of 110 ° A.

EXAMPLE No.15.

In this example the preparation of a catalyst according to the method described in Example No. 4 is described, with the exception that a combination of ultrastable zeolites of cell parameter of 24.57 ° A, surface area of 597 m2, is employed. / g and content of rare earths of 4.0% weight, and an ultrastable zeolite of cell parameter of 24.48 ° A, surface area of 550 m2 / g and a rare earth content of 0.0%. The final catalyst has a total of active species (zeolite + alumina) of 40% weight, zeolite / matrix ratio of 3.0 and a rare earth content of 0.8% weight, the surface area is 312 m2 / g, area of zeolite it is 199 m2 / g, the matrix area of 114 m2 / g and pore volume of 0.2104 crrrVg.

Claims (12)

Ma. ^^^ Having described the invention, it is considered as a novelty and, therefore, what is contained in the following clauses is claimed as property:

1. A process for the preparation of catalyst catalysts for the disintegration of gas oils in a fluidized bed, characterized by the steps of preparing by controlled neutralization of sodium silicate and aluminum salts with dilute sulfuric acid cSP ^, a silicoaluminate, as a binding agent; incorporate a finely dispersed natural clay to silicoaluminate; combining of the resulting mixture with a hydrated alumina of particular textural and acidic characteristics, capable of promoting the primary disintegration of high molecular weight hydrocarbons present in the heavy fraction of gas oil and allowing to reduce the effect of metal poisoning; incorporate a zeolite of the faujasite type "Y" previously exchanged or not with rare earths; form microspheroidal particles and wash and exchange with ammonium and rare earth salts when the zeolite has not been previously exchanged and calcined.

2. A process according to clause 1, characterized in that the promoter agent of mechanical strength can be silica or silica-alumina which is obtained by controlled neutralization, with an acid, from a source of silicon and, where appropriate, aluminum, and brought to a pH less than 3.5.

3. A process in accordance with clauses 1 and 2, characterized in that the source 5 of silicon is selected from among sodium silicate, ammonium silicate, colloidal silica and silicon alkoxides, preferably, sodium silicate and the aluminum source, selected from aluminum sulfate, aluminum nitrate, aluminum chloride, hydroxides aluminum and aluminum alkoxides, preferably aluminum sulfate. Wk?

4. A process according to clause 1, characterized in that the hydrated alumina is selected from boehmite, gibbsite, bayerite and combinations thereof and can be integrated directly or partially or totally peptized with a mineral or organic acid. 15

5. A process in accordance with clauses 1 and 4, characterized in that the texture and acidity properties of the aluminas, after having been calcined at 650 ° C, 2 h are: surface area of 50 to 350 m2 / g, pore volume from 0.18 to 1.20 cm3 / g, average BET pore size from 30 to 300 ° A, acidity by ammonia from 120 to 1200 micro mol / g and acidity by pyridine from 50 to 2700 20 micro moles / g.

6. A process according to clause 1, characterized in that the zeolite used in the preparation of the catalysts has the following characteristics: micropore area from 550 to 700 m2 / g, AI2O3 from 16 to 25% by weight, SiO2 from 58 to 80% weight, rare earths from 0.0 to 15% p, the Na2O content from 0 to 12% and the cell parameter from 24.40 to 24.70 ° A.

7. A process in accordance with clauses 1 and 6, characterized in that the rare earth composition maintains a ratio of 2 to 12 parts by weight of La2O3 Eß for each part of CeO2, preferably 8 to 10 parts of La2O3 per part 10 from CeO

8. A catalyst obtained according to the process of clauses 1 to 7, characterized in that it is constituted by a) a crystalline silicoaluminate of the zeolitic type, whose structure corresponds to the faujasite "Y" which is previously 15 stabilized until reaching a cell size of 24.50 to 24.70 ° A. b) Metals of the lanthanide group, mainly La, Ce, Nd, Pr, among others, in a proportion of 8 to 10 parts of La2O3 for each part of CeO2. c) a hydrated alumina, which depending on the application of the catalyst can be selected from; boehmite, bayerite, gibbsite or mixture of both, c) A binder, depending 20 of the mechanical strength required for specific FCC industrial units, can be selected from silica for medium strength catalysts, or from silica-alumina for high mechanical strength catalysts and d) Natural or heat-treated kaolinite, as a dispersion medium for active species .

9. A catalyst according to clause 8, characterized in that the mechanical strength of its particles is adjusted with the aluminum content in the binder.

10. A catalyst in accordance with clauses 8 and 9, characterized in that the jj? The zeolite employed is a Y-faujasite stabilized to obtain a cell size of 24.50 to 24.70 A and a zeolite content of 20 to 40% by weight, preferably 28 to 34% by weight.

11. A catalyst according to clauses 8 to 10, characterized in that it includes in its formulation an active alumina in its crystalline form which is 15 selected from: boehmite, bayerite, gibbsite and gamma alumina, in a content of 5 to 20% by weight, preferably 8 to 15% by weight.

12. A catalyst according to clauses 8 to 11, characterized in that it is also made up of metals from the group of lanthanides, mainly: La, Ce, 20 Nd and Pr; in a concentration of 0.5 to 4% weight, preferably 1.5 to 3.0% weight. The concentration of these metals maintains a ratio of 2 to 12 parts by weight of La2O3 for each part of CeO2, preferably from 8 to 10 parts of La2O3 for each part of CeO2. . A catalyst according to clauses 1 to 12, characterized in that it comprises a zeolite content of 20 to 40% by weight, preferably 28 to 34% by weight; hydrated alumina of 5 to 20% weight, preferably 8 to 15% weight; rare earths of 0.5 to 4% weight, preferably 1.5 to 3.5% weight; alumina of 30 to 55% weight; Sodium oxide 0.2 to 0.4% weight; density from 0.7 to 0.9 g / cc; pore volume from 0.15 to 0.18 cc / g.