FR2958297A1 - METHOD FOR VALORIZING GASOLINE - Google Patents

Abstract

The present invention relates to a process for adjusting the gasoline / diesel ratio by converting an initial feedstock containing olefins having from 4 to 20 carbon atoms using a crystalline catalyst having reduced diffusion limitations. The process comprises: - treating a feedstock stream containing olefins comprising from 4 to 20 carbon atoms, with or without the presence of a stream containing aromatic compounds, - contacting said one or more catalysts with a catalyst under conditions effective to oligomerize at least a portion of the olefins and optionally alkylate at least a portion of the aromatic compounds, wherein the catalyst is a crystalline compound having a micro / mesoporous structure, selected from crystalline aluminosilicates, aluminophosphates crystalline silico-alumino-phosphates, crystalline zeolites, or the catalyst is a composite material comprising at least 20% by weight of at least one of the crystalline compounds mentioned above, and wherein the volume of mesopore the crystalline compound is at least 0.22 ml / g.

Description

METHOD FOR ENRICHING GASOLINE

The present invention relates to a process for adjusting the gasoline / diesel ratio by converting an initial feedstock containing olefins comprising from 4 to 20 carbon atoms, more preferably from 4 to 15 carbon atoms, preferably from 4 to 15 carbon atoms. 9 carbon atoms, with or without addition of aromatic compounds, using a crystalline catalyst, preferably a zeolite catalyst, having reduced diffusion limitations. Current refineries have to adapt to a changing and ever-changing market, requiring ever more flexibility. This is particularly the case with the gasoline / middle distillate markets, which have evolved significantly over the years: in terms of current and future demand in European markets, a change of target product from gasoline to middle distillates are observed.

In order to respond to the imbalance mentioned above, a good way of readjusting the gasoline / diesel ratio according to the needs of the market is to enrich at least part of the gasoline in middle distillates (fuel for a jet engine, diesel fuel). Today, in a typical refinery, most C4-C8 molecules are found in the gasoline pool. It is important to note that only about 5% of these molecules were initially present in the crude oil used, while cracking during the refining process creates the rest. About 50 percent of the C4 molecules and 40 percent of the C5 molecules that are produced during fluidized catalytic cracking (FCC) are olefinic in nature. At present C4 olefins are used as feedstock for the alkylation and etherification units to create gasoline components having a high octane number, and the higher olefins are usually directly blended into the pool. petrol. In this context, a practical solution for achieving a renewed equilibrium between gasoline and distillates would be to convert the unsaturated molecules (olefins and / or aromatic compounds) contained in the gasoline charge into heavier molecules included in the range of middle distillates (i.e., gas oil and kerosene) by selective oligomerization and / or alkylation of these unsaturated molecules. The present invention relates to a process for producing higher molecular weight organic molecules from a stream of lower molecular weight molecules using a catalyst, preferably a zeolite catalyst, having reduced diffusion limitations. Nowadays, several different technologies are already commercialized to convert olefins by oligomerization.

Typically, known oligomerization processes involve contacting an initial charge of from 4 to 10 carbon atoms with a solid acid catalyst, such as solid phosphoric acid (PSA) catalyst, a crystalline molecular sieve, or an amorphous silica-alumina mixture.

With the APS catalyst, the pressure drop on the catalyst bed (s) increases progressively due to coking, swelling of the catalyst, and is therefore the limiting factor of a cycle time, the unit being stopped once the maximum permissible pressure drop is reached.

The amorphous silica-alumina catalysts have the advantage that they can be used at relatively low temperatures (140 to 160 ° C), thus allowing the use of a wider operating temperature range before the process is limited by side reactions (cracking ...). However, such catalytic systems are not shape selective, and the diesel fuel cut produced has a poor cetane number. The crystalline molecular sieves are used in the MOGD (Mobil Olefins to Gasoline and Distillate) process, available from Mobil (US Pat. US-4,506,106; US-4,543,435) and developed between the 1970s and the 1980s using zeolite ZSM-5 as a catalyst. In a similar manner, Lurgi AG, Germany (patent WO 2006/076942) developed the Methanol to Synfuels (MTS, Methanol as synthetic fuels) process, which is in principle similar to the MOGD process. The Lurgi Way is a combination of the simplified Lurgi MTP technology and the Süd Chemie COD technology (US Patent No. 5,063,187). This process produces gasoline (RON 80) and gas oil (cetane number about 55) in a ratio of approximately 1/4. In contrast to amorphous silica-alumina catalysts, the zeolite catalysts have a selectivity as a function of the microporite-induced form of the zeolite structure, thus making it possible to obtain a gas oil fraction having a good cetane number. However, the micropores can also have a negative impact, which is often illustrated by the reduced access of molecules within the zeolite-cleolithic crystals, on the unwanted absorption effects of the reagents and / or products during the catalytic reaction. It is believed that these steric constraints cause the reduction of zeolite micropore volume accessibility during catalytic action, and it can be said that zeolite crystals have not always been used effectively. At the macroscopic scale, this is illustrated by the need to have higher operating temperatures (generally at least 200 ° C) to limit pore blockage and improve oligomer diffusion, thus greatly limiting the window of because higher operating temperatures favor secondary reactions (secondary reactions such as cracking / isomerization / coking become predominant at temperatures above 300 ° C).

One of the constraints on oligomerization / alkylation is the competition between oligomerization / alkylation on one side and cracking. To avoid these undesirable reactions and to improve the selectivity of the catalyst with respect to the formation of heavy compounds, the design of an optimally accessible catalyst is necessary.

Zeolites with shape selectivity appear to be the most promising catalysts because, by the appropriate choice of materials, the isomerization reaction could be limited. For the conversion of light olefins, typically zeolites having a 10-membered ring are very suitable in their microporous size range.

In order to maximize the effectiveness of the zeolite crystal, a solution for reducing diffusion limitations is to use a zeolite with a small crystal size. Although this concept has been explored for several zeolites (A. Corma, Nature, 396 (1998), 353), in industrial practice the use of small dealuminated zeolite crystals may not always be feasible. A more generally practiced strategy for obtaining materials having reduced diffusion limitations is the creation of a secondary pore system consisting of mesopores (2-50 nm) within the microporous zeolite crystals. In recent years, several other techniques have been developed which make it possible to obtain a structured mesoporosity similar to the microporosity of a zeolite, such as: the recrystallization of the walls of a mesoporous material into a zeolite material ; the preparation of molecular matrices of cationic polymer at the mesoscale; the construction of a mesoporous material using an amphiphilic organosilicon zeolite; direct germination of zeolite crystals using a matrix to form the mesopores. For some of these approaches, it has already been shown that catalysts with improved performance can be obtained in various reactions. For example, the patent WO 2009/153421 describes the synthesis of a crystallized material having a hierarchical and organized porosity and its application in the oligomerization of light olefins. Despite the considerable developments in recent years in the fields of synthesis, characterization and understanding of the mechanisms of formation of these structured mesoporous materials, their effective use in industry remains very limited because of their cost, which is partly related to the high cost of the organic matrix.

Therefore, from a cost point of view, conventional hydrothermal and acid leaching routes remain the most attractive techniques currently in widespread use in the industry. However, the introduction of mesopores by these pathways is not easily controlled and the materials often show a random and unoptimized mesoporosity. In a publication by Janssen et al. (AH Janssen, Angew Chem Int., Ed., 40 (2001), 1102), it has been demonstrated using a three-dimensional electron microscope that a large portion of the mesopores of a vaporized and acid leached zeolite Y commercially available were cavities, non-optimally connected to the outer surface of the zeolite crystal. It is evident that for catalysis it is expected that a system of interconnected cylindrical mesopores will improve the reagent accessibility and the diffusion of the reaction products much more than the mesoporous cavities within the crystal. . Recently, another path has emerged, which is different from the pathways described above. It consists in carrying out a careful desilication of the zeolite synthesized by treatment in an alkaline medium (Ogura M, Chem Lett (2000) 82, Ogura M, Appl., Catal, A Gen. 219 (2001), 33). . Extraction of silicon atoms results in a significant amount of extra porosity within the zeolite crystals. There is an optimal Si / Al ratio for this process, which in the case of ZSM-5 is in the range of 25 to 50 (Groen JC, J. Phys Chem B, 108 (2004) 13062, Groen JC , JACS 127 (2005), 10792). Other publications relate to the alkaline treatment of BEA, FER, MOT (Groen J.C. et al., Microporous Mesoporous Materials, 69 (2004), 29).

Improved catalytic performance has been demonstrated for the liquid phase alkylation of benzene with ethylene using such micro and mesoporosity hierarchical zeolites prepared by ZSM-5 desilication using aqueous solutions of organic bases: the combination in a single material of the catalytic power of the micropores and the improved transport consequence of a complementary mesopore network makes it possible to reduce at least partially the diffusion limitations (Perez-Ramirez J. et al., Appl. , 364 (2009), 191-198). The same conclusions have been reported by Christensen C.H. et al., JACS, (2003), 125, 13370-13371. The Applicant has discovered that the catalysts obtained by this process and therefore having an optimized accessibility of the active sites give improved catalytic performances vis-à-vis the conversion of gasoline into distillates, thus facilitating the design of the process: wider range operating conditions (lower temperature and / or higher LHSV), while preserving higher or at least similar yields and selectivities towards middle distillates. A first subject of the invention relates to a process for enriching gasoline with middle distillates by conversion of a feed containing olefins comprising from 4 to 20 carbon atoms in the presence or absence of aromatic compounds, on a catalyst containing a crystalline compound having a combined micro / mesoporous structure, significantly reducing the diffusion limitations.

The invention therefore relates to a process for the production of middle distillates from a gasoline stream, said process comprising: treating a feed stream containing C 1 olefins comprising from 4 to 20 carbon atoms, with or without the presence of a stream containing aromatic compounds, - contacting said stream (s) with a catalyst under conditions effective to oligomerize at least a portion of the olefins and optionally alkylate at least a portion of the aromatic compounds, wherein the catalyst is a crystalline compound having a micro / mesoporous structure selected from crystalline aluminosilicates, crystalline aluminophosphates, crystalline silico-aluminophosphates, crystalline zeolites, or the catalyst is a composite material comprising at least 20% by weight of minus one of the crystalline compounds mentioned above, and in which the volume of mesopores of the crystalline compound is at least 0.22 ml / g, preferably at least 0.25 ml / g and even more preferably at least 0.30 ml / g. The use of such catalysts in olefin conversion has shown improved activity and efficiency due to greater accessibility of the active sites. Preferably, the mesopore volume of the crystalline compound is at least 0.2 ml / g, more preferably at least 0.3 ml / g. Preferably, the micropore volume of the crystalline compound is less than or equal to 0.20 ml / g, preferably less than or equal to 0.17 ml / g, more preferably less than or equal to 0.15 ml / g.

The mesopore / micropore volume ratio of the crystalline compound may be greater than or equal to 1, preferably greater than or equal to 2, even more preferably greater than or equal to 2.5.

As regards the catalyst Before using the process of the invention, the catalyst, in particular the crystalline micro / mesoporous silicates of zeolite structure, can be subjected to one or more of the following treatments: - Optionally, a dealumination treatment (hydrothermally and / or by acid leaching); so as to (i) reduce the acidity of the material, (ii) increase, although slightly, the mesoporosity of the initial material. Such treatments are described in US Pat. No. 5,601,798. Careful disilication of the material by treatment in an alkaline medium containing at least one strong inorganic base (NaOH, KOH) and / or an organic base (such as TMAOH, TPAOH) ...), at a concentration in the range from 0.1 to 2 M, preferably from 0.15 to 1 M. The alkaline treatment is carried out with stirring at a temperature in the range from room temperature to room temperature. 100 ° C, preferably up to 85 ° C. The term "room temperature" means a temperature in the range of 18 ° C to 25 ° C, preferably 20 ° C.

The duration of the alkaline treatment may be from 5 to 120 minutes, preferably from 10 to 60 minutes, advantageously from 15 to 30 minutes. The obtained material is then filtered and can be subsequently washed with large amounts of polar solvent (for example, deionized pure water).

Optionally, the neutralization of the alkaline solution can be carried out before the filtration step so as to stop the desilication reaction. Indeed, if the desilication becomes too important, this can lead to a significant loss of crystallinity of the structure of the zeolite, which can induce a reduction in the intrinsic activity of the material. If during the preparation of the catalyst, alkali or alkaline earth metals have been used, the material may be subjected to an ion exchange step, typically using ammonium salts or inorganic acids. The catalyst is then generally calcined, for example at a temperature of 400 to 800 ° C at atmospheric pressure for a period of 1 to 10 hours. Optionally, the material may be subjected to a slight final hydrothermal treatment, intended to repair the crystalline defects generated by the alkaline treatment. As already mentioned, the catalyst used in the process of the invention may be a composite material comprising at least 20% by weight of at least one crystalline compound having a micro / mesoporous structure selected from crystalline aluminosilicates, crystalline aluminophosphates, crystalline silico-aluminophosphates, crystalline zeolites or mixtures thereof.

The crystalline compound (s), optionally modified as mentioned above, may be mixed with a binder, preferably an inorganic binder, and shaped into a desired shape, for example into pellets. The binder is selected to be resistant to the temperature and other conditions employed in the reaction of the invention. The binder is preferably an inorganic material selected from clays, silica, metal silicates, metal oxides such as ZrO 2 and / or metals, gels including mixtures of silica oxides and metal oxides. If the binder that is used in conjunction with the crystalline compound is itself catalytically active, this can alter the conversion and / or selectivity of the catalyst. Inactive materials for the binder may optionally be used as diluents to control the amount of conversion so that products can be obtained in an economical and orderly manner without using other means to control the rate of reaction. It is desirable to provide a catalyst having good crush strength. This is because, in commercial use, it is desirable to prevent the catalyst from breaking into powdery materials. Such clay or oxide binders are normally used solely for the purpose of improving the crush strength of the catalyst. The crystalline compound used in the process of the invention preferably has a zeolite structure.

The Si / Al atomic ratio of the zeolitic structure, before the alkaline treatment, is preferably at least 15, preferably at least 25, even more preferably at least 30. The Si / Al atomic ratio of the zeolite structure, before the alkaline treatment, is preferably less than 60, preferably less than 50. Preferably, the volume of mesopores of the crystalline compound used in the present invention is at least 0.2 ml / g, even more preferably at least 0.3 ml / g.

Preferably, the micropore volume of the crystalline compound is less than or equal to 0.20 ml / g, preferably less than or equal to 0.17 ml / g, more preferably less than or equal to 0.15 ml / g. The mesopore volume / micropore volume ratio of the crystalline compound may be greater than or equal to 1, more preferably greater than or equal to 2, still more preferably greater than or equal to 2.5. This crystalline compound can be selected from MFI (ZSM-5, silicalite-1, boralite C, TS-1), MEL (ZSM-11, silicalite-2, boralite D, TS-2, SSZ-46), FER ( ferrierite, FU-9, ZSM-35), MTT (ZSM-23), MWW (MCM-22, PSH-3, ITQ-1, MCM-49), TON (ZSM-22, Theta-1, NU-10) ), EUO (ZSM-50, EU-1), MTW (ZSM-12), MAZ, SAPO-11, SAPO-5, FAU, LTL, BETA MOR, SAPO-40, SAPO-37 and SAPO-41. Preferably, the catalyst has a ZSM-5 type structure.

Regarding the operating conditions The reaction is preferably carried out under the following conditions: - temperature of 125 to 300 ° C, preferably 130 to 280 ° C, still more preferably at 150 ° C, - with a space velocity weightthour space velocity (WHSV) of 0.5 h -1 to 5 h -1, more preferably 0.5 h -1 to 3 h -1, still more preferably 0.5 h -1 to 2 h -1. -1. pressure ranging from atmospheric pressure to 200 barg, preferably from 15 to 100 barg, still more preferably from 15 to 60 barg.

Regarding the feedstock The feedstock of the present invention is typically obtained from petroleum refining or petrochemical operations. In particular, it can be obtained from a thermal cracking stream or catalytic cracking.

The feed containing the olefins can also be obtained from the dehydrogenation of hydrocarbon streams obtained from the treatment of crude oils, natural gas or field condensates. It can also be obtained by dehydrogenation of alcohols.

The composition of the feed (amounts of olefins, aromatic compounds, type of olefins and aromatic compounds) depends on the feedstock to be treated and the conditions used; the process can be carried out with the entire gasoline fraction obtained from a catalytic or thermal cracking step or alternatively with a part thereof. One can also consider a mixture of currents; another example is a reformate and a fraction of LCN gasoline. Preferably, the feedstock is selected from gasolines containing olefins such as LCCS having boiling points in the range of 30 to 100 ° C and a mixture of olefins and aromatic compounds such as LCNs. having boiling points in the range of 30 to 170 ° C. A typical filler composition is shown below in Table 1 for Light Catalytic Cracked Spirit (LCCS) and in Table 2 for Light Cracked Naphtha-Cracked Light Cracked Nitrogen (LCN).

Table 1: Typical Composition of LCCS Density at 15 ° C 0.6518 g / ml Diene Number USP 326 0.11 g I2 / 100 g Bromine Index ASTM D1159 140.8 g Br / 100 g Pressure Reid Vapor ASTM D5191 125.5 kPa ASTM D86 Initial boiling point 27.6 ° CT ° at 5% flight 31 ° CT ° at 50% flight 38 ° CT ° at 95% flight 0 ° CT ° end point boiling point 63.6 ° C Distribution of olefins C4 = 6.80% by weight C5 = 45.44% by weight C6 = 10.65% by weight Total olefins 62.89% by weight Table 2: Typical composition of LCN Density at 15 ° C 0.7178 g / ml ASTM D86 T ° at 5% in flight 52.5 ° CT ° at 95% flight 159.3 ° CT ° boiling point 171.9 ° C PIONA Olefins total 41.7% by weight Aromatic Compounds 13.4% by weight With regard to the reactor A system of several reactors can be used with a cooling system between the reactors by means of which the release of heat from the reaction can be carefully controlled to prevent an excessive temperature above the normal moderate range. This may be an isothermal or adiabatic fixed bed type reactor or a series of such reactors or a moving bed reactor.

Oligomerization / alkylation can be carried out continuously in a fixed bed reactor configuration using a series of "guard" reactors in parallel. It has been found that the various preferred catalysts of the present invention exhibit sufficiently high stability. This makes it possible to carry out the process of oligomerization and / or alkylation continuously in two "guard" reactors in parallel where one or two reactors are in operation, the other reactor undergoes a catalytic regeneration. The catalyst of the present invention can also be regenerated several times. An object of the present invention is to convert an olefin-containing stream to heavy hydrocarbons present in a distillate, using a multi-stage catalytic technique. A multi-reactor system can be used with a reactor cooling system whereby the heat of reaction can be carefully controlled to prevent overheating above the normal moderate range. Advantageously, the maximum temperature difference in a single reactor should not exceed 75 ° C.

Optionally, the pressure difference between the two steps can be used in an intermediate instantaneous separation step. The following examples and figure illustrate the invention without limiting its scope.

Figure 1: sorption-desorption isotherms for a desilted ZSM-5 and a parent sample (TPN: standard condition: 0 ° C and 760 mm Hg).

EXAMPLES Preparation of microporous-mesoporous ZSM-5 A zeolite sample ZSM-5 (catalyst A) (Si / Al = 40) in NH 4 form, 0.1 μm crystal size, marketed by Zeolyst (CBV 8014), is treated in an alkaline medium as follows: 606 ml of NaOH (0.2 M) at 338 K (65 ° C) for 30 minutes with vigorous stirring. The resulting suspension is cooled in an ice bath and the reaction medium is neutralized by adding H2SO4 (1M) until a neutral pH is obtained. The formation of a gel resulting from the precipitation of dissolved silicon atoms is observed and this is removed by washing with large amounts of demineralized water. The recovered solid is then dried at 383 K (110 ° C) overnight. Finally, the samples treated with the alkaline medium are converted to the H form by ion exchange using 200 ml of NH 4 Cl (0.1 M) for 18 hours under reflux. The product is then dried at 110 ° C (60 ° C / h) overnight and then calcined in air at 823 K (550 ° C) for 6 hours. Catalyst B is obtained.

Characteristics of Prepared Microporous-Mesoporous ZSM-5 The main characteristics of catalysts A and B are summarized below (Table 3 and Figure 1) and characterized by the following methods. The chemical composition of the samples (Si / Al molar ratio and Na content) is determined by ICP-AES (Inductively coupled atomic-plasma emission spectroscopy) (Perkin-Elmer 3000 DV). The N2 sorption-desorption isotherms at 77 K are measured in an automated porosimeter (Micromeritics Tristar 3000). Before the measurement, the samples are degassed under vacuum at 573 K for 12 hours. The particle size distribution of the mesopores is obtained by the BJH model (Barett EP, Joyner LG, Halenda PP, J. Am Chem Chem Soc 1951, 73, 373-380, Rouquerol F., Rouquerol J., Sing K., Adsorption by Powders and Porous Solids, Academic Press, San Diego, 1991) applied to the adsorption section of the isotherm. The t-plot method is used to differentiate micro and mesoporosity. Figure 1 shows the nitrogen sorption / desorption isotherms of catalysts A (master sample) and B (ZSM-5 de-silicate). The comparison of the two isotherms of N2 underlines the improved enrichment at an intermediate pressure, revealing the formation of a hierarchical porous system combining a micro and a mesoporosity. As shown in Table 3, the volume of mesopores increased from 0.097 to 0.327 ml / g while the micropore volume decreased from 0.161 to 0.119 ml / g. As a result, the Si / Al ratio decreases from 46 to 34.

Table 3 - Textural properties of parent zeolites and treated with an alkaline medium Si / Al Na catalyst Surface Volume Volume Volume (molar) (total external microporesc mesopore pore weight in ppm) (ml / g) (ml / g) ( m2 / g) (ml / g) A (mother) 46 32 0.258 0.097 0.161 70 B (treated with an alkaline medium) a: adsorbed volume at P / Po = 0.99 b: V meso = V total - V micro c: t-plot method

Catalytic Performance The performances of the two catalysts (catalysts A and B) are evaluated on the oligomerization of a model charge consisting of a mixture of n-heptane (nC7) and 1-hexene (106 =). The following operating conditions are used: 55 barg, WHSV (weight hourly space velocity) of 1 to 2 h -1, temperature ranging from 150 to 200 ° C.

The performances of the parent zeolite (Catalyst A) and the sample treated with an alkaline medium (Catalyst B) are presented in Table 4.

Table 4 - Yield of the different groups of products at 55 barg, WHSV of 1 or 2 h-1, for different temperatures on model load (nC7 / 106 =) Catalyst A Sample Catalyst B Feed 1C6 = / nC7 1C6 = / nC7 47 / 53% by weight 46/54% by weight P (barg) 55 55 55 55 Temperature (° C) 200 149 149 149 WHSV (h-1) 1 1 1 2 H2 / HC (Nl / l) none none 106 = conv. (% in 94.7 63.5 94.7 74.6 wt.) Yield (wt%) 106 = residual 2.5 17.2 2.5 10.9 nC7 52.8 52.8 53.6 53 6 Heavy (C7 +) 41.0 27.6 41.1 34.2 Crackers 3.7 2.4 2.9 1.3 Oligomeric distribution (% by weight) C12 = 81.2 93.4 79, 84.2 C18 = 16.7 6.3 16.3 15.0 C24 = 2.2 0.3 4.1 0.8 C30 = 0.0 0.0 0.0 0.0 C alkanes having x carbon atoms C.- represents olefins having x carbon atoms

These results show that by using a catalyst as defined in the invention which has a particular micro / mesoporous structure, a significant reduction in the inlet temperature is successfully obtained without this having an impact on the overall conversion of the olefins. in C6. This emphasizes the improved accessibility of the acidic sites of zeolites treated with an alkaline medium compared to the parent zeolite. At a temperature of 150 ° C, a better conversion of the olefins with the ZSM-5 treated with an alkaline medium having a WHSV twice higher (2 h-1 compared to 1 h-1) compared to that of the zeolite mother.

Claims (8)

REVENDICATIONS1. A method of manufacturing middle distillates from a gasoline stream, said process comprising: - treating a feedstock stream containing C n olefins comprising from 4 to 20 carbon atoms, with or without the presence of a stream containing aromatic compounds, - contacting said stream (s) with a catalyst under conditions effective to oligomerize at least a portion of the olefins and optionally alkylate at least a portion of the aromatic compounds, wherein the catalyst is a crystalline compound having a micro / mesoporous structure selected from crystalline aluminosilicates, crystalline aluminophosphates, crystalline silico-aluminophosphates, crystalline zeolites, or the catalyst is a composite material comprising at least 20% by weight of at least one one of the crystalline compounds mentioned above, and wherein the mesopore volume of the crystalline compound is at least 0.22 ml / g, preferably at least 0.25 ml / g, and still more preferably at least 0.30 ml / g. 2. Method according to claim 1, characterized in that the crystalline compound has a zeolite type structure, preferably of ZSM-5 type. 3. Method according to claim 1 or 2, characterized in that the catalyst is subjected to treatment in an alkaline medium before use. 4. Method according to claim 3, characterized in that the alkaline medium is a solution of NaOH having a concentration of 0.1 to 2 M, preferably 0.15 to 1 M. 5. Process according to any one of the preceding claims, characterized in that the conversion of olefins is carried out at a temperature of 125 to 300 ° C, preferably 130 to 280 ° C. 6. Process according to any one of the preceding claims, characterized in that the weight hourly space velocity (WHSV) of the olefin conversion is carried out from 0.5 h -1 to 5 h -1, more preferably 1 hour. -1 to 3 h -1, even more preferably 2 h -1. 7. Method according to any one of the preceding claims, characterized in that the pressure of the olefin conversion is carried out from atmospheric pressure to 200 barg, more preferably from 15 to 100 barg, still more preferably from 15 to 60 barg . 8. Process according to any one of the preceding claims, characterized in that the feedstock is selected from gasolines containing olefins such as LCCS having boiling points in the range of 30 to 100 ° C. or a mixture of olefins and aromatic compounds such as LCNs having boiling points in the range of 30 to 170 ° C.