RU2768118C1 - Method of producing catalyst - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a catalyst for producing concentrates of aromatic compounds. Method of producing the catalyst for producing concentrates of aromatic compounds involves the following steps: a. adding HZSM-5 to the peptized pseudoboehmite to obtain a mixture of zeolite and pseudoboehmite, b. adding amorphous aluminosilicate with molar ratio Si/Al from 0.2 to 0.5 to the mixture obtained at step (a) to obtain a molding compound, c. molding, drying and calcining the molding compound to obtain a catalyst composition, d. alkaline treatment of catalyst composition obtained at step (c), e. washing from sodium catalyst composition obtained at step (d), drying and calcination, f. impregnating the catalyst composition obtained at step (e) with solutions of zinc salts and rare-earth elements, drying and calcining to obtain the following chemical composition in terms of catalyst oxides: i. silicon dioxide in amount of 53.0 to 85.0 wt.%, ii. aluminum oxide in amount of 11.5 to 43.0 wt.%, iii. zinc oxide in amount of 1.4 to 2.9 wt.%, iv. oxides of rare-earth elements in amount of 0.9 to 2.0 wt.%. Obtained catalyst is especially effective for processes of combined processing of hydrocarbon fractions, oxygenates and olefin-containing fractions.

EFFECT: reduced output of C₃-C₄ hydrocarbons to 22 wt.% and less when producing a product with content of aromatic compounds in the C₅₊ fraction of the product of not less than 45 wt.%; it is also possible to increase the content of aromatics with one alkyl substitute in the C₅₊ fraction of product to 14,5–26,9 wt.%.

10 cl, 5 tbl, 18 ex

Description

The invention relates to the field of oil refining and petrochemical industry. More specifically, the invention relates to a process for the preparation of a catalyst for the production of aromatic compound concentrates. The proposed method allows to obtain a catalyst effective for the processes of joint processing of hydrocarbon fractions, oxygenates and olefin-containing fractions.

BACKGROUND OF THE INVENTION

WO 2017155431 describes a process for the production of gasoline from mixtures of hydrocarbon fractions, gaseous olefin fractions and oxygenates. A variant of the invention is described in which a zeolite-containing catalyst is used, where a synthetic amorphous aluminosilicate or an inorganic oxide is used as a binder, which is a mixture of 30-70 wt. % aluminum oxide and 70-30 wt. % silicon oxide. Described is a catalyst for producing liquid hydrocarbons from dimethyl ether, including a crystalline aluminosilicate of the pentasil type: 63-69.8 wt. %, zinc oxide: 0.5-3.0 wt. %; oxides of rare earth elements: 0.1-5.0 wt. %, cobalt oxide: 0.05-2.5 wt. %, binder: the rest. The document does not consider the influence of the original components of the binder on the catalytic properties of the catalyst.

RU 2658832 describes a catalyst for the conversion of hydrocarbons, alcohols, ethers or mixtures of alcohols and ethers. The preparation of catalysts containing zeolite ZSM-5 or ZSM-11 with a molar ratio of SiO ₂ /Al ₂ O ₃ =20-150 mol/mol and a residual sodium oxide content of not more than 0.4 wt. %, zinc oxide and/or gallium oxide, lanthanum oxide, binder (gamma - Al ₂ O ₃ , and/or silicon dioxide, and/or synthetic aluminosilicate, and/or clay, and/or zirconium dioxide and others) and oxide strontium, and the content of strontium oxide in the composition of the catalyst is from 0.01 to 3.0 wt. %, the zeolite content is from 20.0 to 90.0 wt. %, the content of zinc oxide is from 0.1 to 6.0 wt. %, the content of gallium oxide is from 0.1 to 3.0 wt. %, the content of lanthanum oxide (La ₂ O ₃ ) is from 0.1 to 5.0 wt. %, the content of the binder component - the rest up to 100 wt. %. A variety of optional catalyst components are also provided. The document assumes the use of strontium compounds for the preparation of a catalyst, which complicates industrial production (taking into account acute toxicity, explosiveness, and fire hazard of such raw materials). No mention is made of the consequences of the use of a catalyst for the processes of co-processing of hydrocarbon fractions, oxygenates and olefin-containing fractions. Based on the description of the document, the composition of the binder does not affect the achieved result: the use of any of dozens of binder options (gamma - Al ₂ O ₃ and / or silicon dioxide, and / or synthetic aluminosilicate, and / or clay, and / or zirconium dioxide and others) lead to similar results.

EA 201891760 describes a catalyst for the co-conversion of hydrocarbon fractions and oxygenates into high-octane fuel components or aromatic hydrocarbons. The preparation of a catalyst containing zeolite HZSM-5 with a silicate module SiO ₂ /Al ₂ O ₃ =50-81.9, with a residual amount of sodium oxide of 0.04-0.15 wt. %, subjected to thermocouple treatment to the stage of preparation of the catalyst, in the amount of 65-69.8 wt. %, zinc oxide in the amount of 1.5-2 wt. %, oxides of rare earth elements in the amount of 1-2 wt. %, oxides and/or sulfides of Group VIII metals in the amount of 0.5-1 wt. %, binder - the rest up to 100%, while a mixture of aluminum oxide is used as a binder - 30.1-69.9 wt. %, and silicon oxide - 69.9-30.1 wt. %. This method of obtaining a catalyst is considered as the closest to the present invention and is taken as a prototype. The document proposes to carry out the thermosteam treatment of zeolite, which complicates the industrial production of the catalyst (the need to use specialized equipment). No mention is made of the consequences of the use of a catalyst for the processes of co-processing of hydrocarbon fractions, oxygenates and olefin-containing fractions.

DISCLOSURE OF THE INVENTION

The present invention solves the problem of producing aromatic concentrates. As a technical result, a decrease in the yield of hydrocarbons C ₃ -C ₄ to 22 wt. % or less. Moreover, this result is achieved when obtaining a product with a content of aromatic compounds in the C ₅₊ fraction of the product of at least 45 wt. %. It is also possible to increase the content of aromatics with one alkyl substituent in the C ₅₊ fraction of the product up to 14.5–26.9 wt %. %.

The above technical results are achieved by the proposed method for producing a catalyst for the production of concentrates of aromatic compounds, which includes the following stages:

but. adding HZSM-5 to peptized pseudoboehmite to obtain a mixture of zeolite and pseudoboehmite,

b. adding an amorphous aluminosilicate with a Si/Al molar ratio of 0.2 to 0.5 to the mixture obtained in step (a) to obtain a molding composition,

c. molding, drying and calcining the molding mass to obtain a catalyst composition,

d. alkaline treatment of the catalyst composition obtained in step (c),

e. washing the catalyst composition obtained in step (d) from sodium, drying and calcining,

f. impregnation of the catalyst composition obtained in step (e) with solutions of zinc and rare earth salts, drying and calcination.

It is possible to carry out the invention, in which an aqueous solution of alkali with a pH of 10 to 14, preferably a pH of 12 to 14, is used for alkaline treatment.

It is possible to execute the invention, in which an aqueous solution of sodium hydroxide with a concentration of 0.01-0.5 M is used for alkaline treatment.

It is possible to execute the invention, in which the alkali treatment is carried out by heating up to 30-80°C.

It is possible to carry out the invention in which the impregnation of the catalyst composition is carried out using moisture capacity impregnation or impregnation in excess solution.

It is possible to execute the invention, in which the resulting catalyst includes zeolite ZSM-5 in an amount of from 50.0 to 85.0 wt. %, where

a. the pore volume of the catalyst is from 0.15 to 0.29 cm ³ /g,

,b. the average pore diameter of the catalyst is from 38 to 55

,

c. the ratio of weak and strong acid sites of the catalyst is from 1.2 to 2.5,

moreover, the catalyst includes, by chemical composition, in terms of oxides:

d. silicon dioxide in an amount from 53.0 to 85.0 wt. %,

e. aluminum oxide in an amount from 11.5 to 43.0 wt. %,

f. zinc oxide in an amount of 1.4 to 2.9 wt. %,

g. oxides of rare earth elements in an amount of 0.9 to 2.0 wt. %. It is possible to execute the invention, in which the resulting catalyst

is used for the co-processing of hydrocarbon fractions, oxygenates and olefin-containing fractions into aromatic compound concentrates, preferably the catalyst is used for a process for producing aromatic compound concentrates, in which three streams are used as feedstock, one of which includes a hydrocarbon fraction, the second stream includes an oxygenate, the third the stream includes an olefin-containing fraction, where the olefin-containing fraction includes one or more olefins selected from the group including: ethylene, propylene, normal butylenes, isobutylene, in a total amount of from 10.0 to 50.0 wt. %.

It is possible to carry out the invention, in which the rare earth elements include one or more elements selected from the group including: lanthanum, praseodymium, neodymium, cerium.

It is possible to execute the invention, in which the resulting catalyst does not contain one or more elements selected from the group including: platinum metals, iron, cobalt, nickel.

It is possible to carry out the invention, in which the zeolite has a silica module SiO ₂ /Al ₂ O ₃ in the range from 50 to 90, preferably from 60 to 80.

IMPLEMENTATION OF THE INVENTION

The proposed method for producing a catalyst includes the following steps:

a. adding HZSM-5 to peptized pseudoboehmite to obtain a mixture of zeolite and pseudoboehmite,

b. adding an amorphous aluminosilicate with a Si/Al molar ratio of 0.2 to 0.5 to the mixture obtained in step (a) to obtain a molding composition,

c. molding, drying and calcining the molding mass to obtain a catalyst composition,

d. alkaline treatment of the catalyst composition obtained in step (c),

e. washing the catalyst composition obtained in step (d) from sodium, drying and calcining,

f. impregnation of the catalyst composition obtained in step (e) with solutions of zinc and rare earth salts, drying and calcination.

Stage (a)

Peptized pseudoboehmite and HZSM-5 are mixed. Optionally, the mixture is evaporated with stirring to a pasty consistency. The result is a mixture of zeolite and pseudoboehmite. Wherein:

- HZSM-5 (zeolite ZSM-5 in H-form) can be obtained by already known methods, for example, by ion exchange of the sodium form of the ZSM-5 zeolite to obtain the ammonium form of the zeolite, and subsequent calcination of the ammonium form of the zeolite to obtain the ZSM-zeolite 5 in H-form. Optionally, the zeolite may be dried and/or calcined and/or milled before mixing. HZSM-5 may contain trace amounts of sodium.

- Peptized pseudoboehmite can be obtained by known methods. For example, peptized pseudoboehmite can be obtained by treating a pseudoboehmite powder or pellet with an aqueous solution of an inorganic acid, preferably nitric acid. Pseudoboehmite (aluminum hydroxide with a pseudoboehmite structure) is commercially available.

- Optionally, peptized pseudoboehmite can be obtained from thermally activated aluminum hydroxide (TCA product). At the same time, the preparation of peptized pseudoboehmite may include the stages of washing from sodium, autoclaving, hydration, the procedure for which may differ depending on the configuration of the equipment of a particular production. This design allows to achieve an additional technical result: to increase the mechanical strength of the catalyst, and the losses of the catalyst during production, caused by the production of catalyst particles with a size of less than 1 mm, are reduced.

- Optionally, peptized pseudoboehmite can be obtained from thermally activated aluminum hydroxide, where the process for obtaining pseudoboehmite includes the following steps:

a. hydration of thermally activated aluminum hydroxide at a molar ratio of nitric acid/alumina 0.01 to 0.02;

b. washing from sodium suspension obtained in stage (a);

c. treatment of the suspension obtained in step (b) in an autoclave at a molar ratio of nitric acid/alumina from 0.10 to 0.20.

- Optionally, peptized pseudoboehmite can be obtained from thermally activated aluminum hydroxide, where the process for obtaining pseudoboehmite includes the following steps:

a. washing thermally activated aluminum hydroxide from sodium;

b. treatment of the suspension obtained in step (b) in an autoclave at a molar ratio of nitric acid/alumina from 0.01 to 0.02;

c. hydration of the suspension obtained in stage (b) at a molar ratio of nitric acid/alumina from 0.10 to 0.20.

Step (b)

To the mixture obtained in stage (a), add an amorphous aluminosilicate with a molar ratio of Si/Al from 0.2 to 0.5. The resulting mass is evaporated to formability. As a result, a molding mass is obtained. Wherein:

- Amorphous (X-ray amorphous) aluminosilicate can be obtained by known methods, for example, by co-precipitation from aqueous solutions of aluminum sulfate, sodium silicate and ammonia. The parameters of co-precipitation operations, in particular, salt concentration, pH, mixing order, temperature, time are selected by known methods, so that the resulting amorphous aluminosilicate has an acid module Si/Al in the range 0.2-0.5 (the molar ratio Si/Al in the range

The following examples 1-7 describe the catalysts obtained by the proposed method. Examples 8-9 below describe the reference catalysts (see Tables 1 and 2). Examples 10-18 below describe the results of using the catalyst samples of examples 1-9 to obtain concentrates of aromatic compounds (see Table 5).

The catalyst obtained by the proposed method shows a surprisingly low yield of C ₃ -C ₄ hydrocarbons under conditions for obtaining products with a high content of aromatics. Known zeolite catalysts are generally capable of producing aromatic concentrates to some extent. However, attempts to increase the concentration of aromatics in the product above 45 wt. % face an undesirable increase in the yield of hydrocarbons C ₃ -C ₄ . For example, the use of a catalyst with a one-component binder (a binder based on amorphous aluminosilicate without the addition of peptized pseudoboehmite) makes it possible to obtain a product with an aromatic content of more than 45 wt. %, but at the same time leads to a high yield of non-target fraction of hydrocarbons C ₃ -C ₄ (45 wt. % based on the submitted hydrocarbon fraction, see below comparative example 18). At the same time, the use of the catalyst obtained by the proposed method can reduce the yield of hydrocarbons C ₃ -C ₄ to 16-22 wt. % per supplied hydrocarbon fraction (see examples 10-16 and Table 5). The yield of hydrocarbons With ₁ -C ₂ does not exceed 5 wt. % per supplied hydrocarbon fraction.

The catalysts for examples 1-9 include, by chemical composition, in terms of oxides (see Table 2):

a. silicon dioxide in an amount of from 55.0 to 85.0 wt. %,

b. aluminum oxide in an amount from 11.5 to 43.0 wt. %,

c. zinc oxide in an amount of 1.4 to 2.9 wt. %,

d. oxides of rare earth elements in an amount of 0.9 to 2.0 wt. %.

The catalysts for examples 1-9 include zeolite ZSM-5 in an amount of from 50.0 to 85.0 wt. %.

It was found that the coincidence of the chemical composition of the catalyst and the proportion of zeolite in itself does not guarantee the achievement of a technical result. In particular, the catalyst of Example 1 and the catalyst of Comparative Example 9 show the same chemical compositions and proportion of zeolite (see Table 2). However, only the use of the catalyst according to the invention (example 1) leads to a decrease in the production of hydrocarbons C ₃ -C ₄ to a level of less than 22 wt. % (see Table 5). Thus, the method of obtaining a catalyst affects the possibility of achieving a technical result.

It was found that the use of the catalyst obtained by the proposed method allows to increase the proportion of aromatics with one alkyl substituent in the product. In this case, the use of a mixture of pseudoboehmite and amorphous aluminosilicate for the preparation of a binder is not sufficient in itself to achieve the required results. In particular, this observation demonstrates a comparison of examples 10 (using the catalyst according to the invention, example 1) and 17 (using the catalyst according to comparative example 8). Both catalysts include binders based on a mixture of pseudoboehmite and amorphous aluminosilicate, with the same chemical composition (see Tables 1 and 2). However, the catalyst preparation method of Example 8 (comp.) includes an amorphous aluminosilicate with an acid modulus of 0.6 (Si/Al molar ratio), while the method for preparing the catalyst of the invention involves the use of an amorphous aluminosilicate with an acid module of 0.2-0.5.

The use of an amorphous aluminosilicate with an acid modulus of less than 0.2 or more than 0.5 does not make it possible to achieve an aromatic content with one alkyl substituent in the C ₅₊ fraction of the product of more than 10 wt. %. In particular, the use of a reference catalyst (Example 8) reduces the proportion of aromatics with one alkyl substituent in the C ₅₊ fraction of the product to 9.6 wt. % compared to 17.8 wt. % according to the invention (example 1, see Table 5). At the same time, when using the catalyst according to the invention, the positive effect is maintained regardless of the total content of aromatics in the product. Frequently, in Examples 10-16, the ratio of aromatics with one alkyl substituent to total aromatics is kept in the range of 0.3-0.4 (wt %/wt %). At the same time, comparison examples are limited to the proportion of monoalkyl-substituted aromatic compounds at the level of 0.2 of the total aromatic content (see Table 5).

Stage (s)

The molding mass obtained in step (b) is molded, dried and calcined. Optionally, the granules are dried before drying. The result is a catalyst composition. Wherein:

- Already known methods of shaping catalysts based on zeolites can be used, for example, extrusion molding, tableting.

- Temperature, temperature rise rate, duration of the withering (optional), drying and roasting operations may vary depending on the conditions of a particular production, and can be selected by already known methods in the course of routine experiments.

Stage (d)

The catalyst composition obtained in step (c) is subjected to an alkaline treatment. The result is a catalyst composition that has undergone alkaline treatment. Wherein:

- For alkali treatment, an alkali solution with a pH of 10 to 14 is used, preferably a pH of 12 to 14. Preferably, the alkali solution comprises an alkali or alkaline earth metal hydroxide, more preferably sodium hydroxide. Most preferably, an aqueous solution of sodium hydroxide with a concentration of 0.01 to 0.5 mol/l is used for alkaline treatment.

- Optionally, after treatment with an alkali solution, the catalyst composition is washed with water from alkali residues and dried. Optionally, it is possible to calcinate the catalyst composition after drying. Preferably, an excess of alkali solution is used for alkali treatment.

- Temperature, rate of temperature rise, duration of drying and calcining operations may vary depending on the conditions of a particular production, and can be selected by already known methods in the course of routine experiments.

Stage (e)

The catalyst composition obtained in step (d) is washed free of sodium, dried and calcined. Wherein:

- Washing from sodium can be carried out by ion exchange. Preferably, the catalyst composition is treated with an aqueous solution containing ammonium ions. Most preferably, the catalyst composition is treated with an aqueous solution of ammonium chloride or ammonium nitrate.

- Ion exchange methods are known in the field of zeolite catalysts. The amount of ammonium salt, water, the ratio of solid:liquid by weight, time and temperature of treatment can be selected by known methods. Optionally, the ion exchange is carried out without stirring at room temperature. Optionally, it is possible to carry out repeated ion exchange and washing with water. Preferably, the final content of Na ₂ O in the catalyst composition does not exceed 0.15 wt. %.

- The temperature, the temperature rise rate, the duration of the drying and calcining operations may vary depending on the conditions of a particular production, and can be selected by known methods.

Stage (f)

The catalyst composition obtained in step (e) is impregnated with solutions of zinc and rare earth salts, dried and calcined. The result is a catalyst. Wherein:

- The impregnation can be carried out by known methods, for example by the method of impregnation according to the moisture capacity or by the method of impregnation in excess solution.

- Optionally, when impregnating by moisture capacity, the volume of the impregnating solution (V, ml) is calculated by the formula: V=B⋅m, where B is the moisture capacity of the carrier, ml/g, m is the mass of the carrier, g.

- Preferably, salts of inorganic acids are used as zinc salts, most preferably zinc nitrate.

- Preferably, salts of inorganic acids are used as salts of rare earth elements, most preferably nitrates of rare earth elements (REE). Preferably, the rare earth elements are selected from the group consisting of lanthanum, praseodymium, neodymium, cerium, and mixtures thereof.

- Optionally, an industrial REE concentrate can be used as a source of rare earth elements. Commercial REE concentrates usually contain mixtures of salts of rare earth elements, especially lanthanum and cerium. The proposed method for producing a catalyst can use industrial REE concentrates without preliminary purification and separation, which reduces the cost of producing catalysts on an industrial scale.

- The temperature, the temperature rise rate, the duration of the drying and calcining operations may vary depending on the conditions of a particular production, and can be selected by known methods.

CHARACTERISTICS OF THE PRODUCED CATALYST

The textural properties of the catalyst samples (including the pore volume and pore size distribution) were determined by the low-temperature nitrogen adsorption method. The pore volume was determined from the desorption curve. Pore size distribution curves were calculated using the BJH method.

The acid properties of the catalyst samples (including the ratio of weak and strong acid sites) were determined by the method of thermally programmed ammonia desorption (TPD NH ₃ ). At the same time, the TPD profiles of NH ₃ for the catalysts obtained by the proposed method include two pronounced peaks:

low-temperature peak of desorption of ammonia from weak acid centers and acid centers of medium strength, T _{max (I)} = 170-190 ° C,

high-temperature peak of desorption of ammonia from strong acid sites, T _max(II) =365-390°C.

The ratio between weak and strong acid sites (µmol/g : µmol/g) is defined as the ratio of Low temperature peak, µmol/g to High temperature peak, µmol/g.

Catalyst Composition

The catalyst obtained by the proposed method preferably includes, in terms of chemical composition, in terms of oxides:

silicon dioxide in an amount of from 55.0 to 85.0 wt. %,

aluminum oxide in an amount from 11.5 to 43.0 wt. %,

zinc oxide in an amount of 1.4 to 2.9 wt. %,

oxides of rare earth elements in an amount of 0.9 to 2.0 wt. %.

While the catalyst preferably includes, in terms of phase composition, zeolite ZSM-5 in an amount of from 50.0 to 85.0 wt. %, as well as a binder and promoters. The chemical composition of the catalyst, wt. % and the proportion of zeolite in the catalyst, wt. %, non-additive (do not add up to 100 wt. %), since the proportion of zeolite refers to the phase composition of the catalyst.

- Binder. The proposed catalyst includes a binder, including the chemical composition, in terms of oxides, a mixture of SiO ₂ and Al ₂ O ₃ (combined binder). However, the proportion and in particular the chemical composition of such a binder, as a rule, cannot be unambiguously determined in a zeolite catalyst sample by experimental methods. In this regard, the present invention limits the proportion and chemical composition of the binder through the proposed combination of the chemical composition of the catalyst and the proportion of zeolite in the catalyst, which can be determined in the finished sample of the catalyst by experimental methods.

In particular, in the following examples 1-7 according to the invention, the catalyst comprises from 50.0 to 85.0 wt. % zeolite ZSM-5 (determination of the mass fraction of zeolite in the finished catalyst was carried out by X-ray phase analysis), where the rest is up to 100 wt. % falls on the binder and promoters. The share and chemical composition of the binder in the finished samples of the catalyst is not determined experimentally. The estimated content of the binder in the catalysts for examples 1-7 is 11.5-46.6 wt. % by weight of the catalyst. The calculated chemical composition of the binder, in the catalysts according to examples 1-7, in terms of oxides of SiO ₂ and Al ₂ O ₃ is 5.0-29.0 wt. % silicon oxide and 71.0-95.0 wt. % aluminum oxide by weight of the binder.

- Promoters - compounds of rare earth elements, alkali metals, alkaline earth metals, metals of groups III-VIII A/B), preferably zinc oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide.

It is possible to execute the invention, in which the catalyst does not contain one or more elements selected from the group including: platinum metals, iron, cobalt, nickel. Given the different sensitivity of analytical chemistry methods to the determination of metal content, the term “does not contain” means that the total content of iron, cobalt, nickel in the catalyst does not exceed 0.10 wt. %, preferably does not exceed 0.05 wt. %, most preferably does not exceed 0.01 wt. %.

- The catalyst may include impurity amounts of sodium oxide, for example, from 0.01 to 0.15 wt. % sodium oxide.

- ZSM-5 zeolites are generally characterized by modulus (molar ratio of SiO ₂ /Al ₂ O ₃ ). The proposed method for preparing the catalyst allows the use of zeolites with a wide range of modules, in particular, it is possible to use a zeolite with a silica module SiO ₂ /Al ₂ O ₃ in the range of 30-120, preferably 50-90, most preferably 70-80.

The chemical composition of zeolite catalysts is usually given based on the catalyst calcined at a certain temperature. In particular, for the catalysts according to examples 1-9, the chemical composition of the catalyst, wt. %, in terms of oxides, is given for samples calcined at 550°C. This calcination temperature is not related to the calcination operations carried out in the catalyst preparation process, and refers to the calcination of the catalyst in order to determine its chemical composition by analytical chemistry methods, in particular to remove sorbed moisture.

, соотношение слабых и сильных кислотных центров катализатора 1.2-2.5), характерных для образцов катализатора, полученных по предлагаемому способу.It was found that the coincidence of the chemical composition of the catalyst and the proportion of zeolite in itself does not guarantee that the catalyst has a combination of textural and acidic characteristics (the pore volume ^of the catalyst is 0.15–0.29 cm3/g, the average pore diameter of the catalyst is 38–55

, the ratio of weak and strong acid sites of the catalyst 1.2-2.5), characteristic of the catalyst samples obtained by the proposed method.

, соотношение слабых и сильных кислотных центров катализатора 1.2-2.5 (см. Таблицу 2). В результате нежелательный выход углеводородов С₃-С₄ увеличивается с 22 до 43-45 мас. %, при этом не происходит увеличения концентрации ароматики в продукте (см. Таблицу 5, примеры 17-18, применение катализаторов по сравнительным примерам 8-9).In particular, the catalyst of example 1, obtained by the proposed method, and the comparison catalysts of examples 8 and 9, have the same chemical composition and the proportion of zeolite (see Table 2). However, the comparison catalysts according to examples 8 and 9 do not achieve the following combination of texture and acid characteristics: the pore volume of the catalyst is 0.15-0.29 cm ³ /g, the average pore diameter of the catalyst is 38-55

, the ratio of weak and strong acid sites of the catalyst 1.2-2.5 (see Table 2). As a result, the undesirable yield of C ₃ -C ₄ hydrocarbons increases from 22 to 43-45 wt. %, while there is no increase in the concentration of aromatics in the product (see Table 5, examples 17-18, the use of catalysts according to comparative examples 8-9).

- ZSM-5 zeolites are generally characterized by modulus (molar ratio of SiO ₂ /Al ₂ O ₃ ). The proposed method for preparing the catalyst allows the use of zeolites with a wide range of modules, in particular, it is possible to use a zeolite with a silica module SiO ₂ /Al ₂ O ₃ in the range of 30-120, preferably 50-90, most preferably 70-80.

- The resulting catalyst may include impurity amounts of sodium oxide, for example, from 0.01 to 0.15 wt. % sodium oxide.

- It is possible to execute the invention, in which the resulting catalyst does not contain one or more elements selected from the group including: platinum metals, iron, cobalt, nickel. Given the different sensitivity of analytical chemistry methods to the determination of metal content, the term “does not contain” means that the total content of iron, cobalt, nickel in the catalyst does not exceed 0.10 wt. %, preferably does not exceed 0.05 wt. %, most preferably does not exceed 0.01 wt. %.

CATALYST APPLICATION

It is possible to use the catalyst obtained by the proposed method for the joint processing of hydrocarbon fractions, oxygenates and olefin-containing fractions to obtain aromatic concentrates.

Hydrocarbon fraction

Suitable hydrocarbon fractions are characterized by an end point of the boiling point of not more than 215°C. In particular, the end of the boil may be 200°C, 180°C, 160°C or 85°C. Preferably, the end point of the boil is at most 180°C. The end boiling point (End Boiling Point, °C) can be determined, for example, according to GOST 2177 or ASTM D 86.

The initial boiling point has little effect on the results achieved, in particular because hydrocarbon fractions, incl. oil fractions and semi-products of petrochemical industries may contain various amounts of dissolved gases C ₁ -C ₄ , depending on the internal requirements of industrial production. The initial boiling point of the hydrocarbon fraction may be, for example, 62°C, 85°C, 140°C. Preferably, the initial boiling point is at least 62°C.

The detailed hydrocarbon composition of the hydrocarbon fraction, for example, determined according to ASTM D6729, has little effect on the ability to achieve technical results, incl. because a typical hydrocarbon fraction contains hundreds of individual chemicals. Table 3 lists special cases of the chemical composition of the hydrocarbon fractions used in examples 10-18. The hydrocarbon fraction may include mixtures of normal paraffins, isoparaffins, olefins, naphthenes and aromatics (PIONA). However, one or more chemical groups selected from a list including normal paraffins, isoparaffins, olefins, naphthenes, aromatic hydrocarbons may be absent from the hydrocarbon fraction.

Oxygenate

Suitable oxygenates are aliphatic alcohols or C ₁ -C ₄ ethers. In particular, the oxygenate may be selected from the group consisting of: methanol, ethanol, dimethyl ether, and mixtures thereof, incl. with water. Oxygen may contain impurities, such as aldehydes, carboxylic acids, esters, aromatic alcohols, unsaturated (unsaturated) alcohols.

Olefin-containing fraction

Suitable olefin-containing fractions include from 10 to 50 wt. % olefins C ₂ -C ₄ (ethylene, propylene, normal butylenes, isobutylene or mixtures thereof). The olefin-containing fraction may contain inert or weakly reactive components other than olefins, for example: methane, ethane, propane, butane, hydrogen, nitrogen. For example, the olefin-containing fraction may contain from 0.5 to 8 wt. % hydrogen, preferably from 2.3 to 8.0 wt. % hydrogen. Such executions favorably distinguish the proposed method for producing a catalyst, since due to the use of the resulting catalyst, it is possible to suppress the side reactions of hydrogenation of olefins C ₂ -C ₄ with feedstock hydrogen. This makes it possible to use low-demand sources of dilute olefins as raw materials without their preliminary purification from hydrogen. The olefin-containing fraction may be, for example, thermal or catalytic cracking gases, incl. dry catalytic cracking gas (SGCC), coking off-gas, as well as their mixtures.

OCHI - octane number, determined by the research method. Preferably determined according to ASTM D2699 or GOST 8226.

Products

The catalysts obtained by the proposed method are particularly effective for the production of concentrates of aromatic compounds in the processes of joint processing of hydrocarbon fractions, oxygenates and olefin-containing fractions. As a result of the joint processing of hydrocarbon fractions, oxygenates and olefin-containing fractions, a liquid hydrocarbon product (mainly C ₅₊ hydrocarbons), a gaseous hydrocarbon product (mainly C ₁ -C ₄ hydrocarbons) and an aqueous fraction (formed as a result of the presence of oxygenates in the feedstock) are formed. ). The liquid hydrocarbon product may contain dissolved gases C ₁ -C ₄ , the amount of which is determined based on the needs of a particular enterprise. At the same time, the concentrate of aromatic compounds is characterized as a liquid hydrocarbon product with an aromatic content of more than 45 wt. %.

Examples

Characteristics of the catalysts and methods for their preparation according to the invention are described in examples 1-7. Characteristics of the reference catalysts and methods for their preparation are described in examples 8-9. Examples 10-18 describe the results of using the samples of catalysts according to examples 1-9 under conditions of co-processing of hydrocarbon fractions, oxygenates and olefin-containing fractions to obtain concentrates of aromatic compounds.

The catalyst according to comparative example 8 differs from the catalysts obtained according to the proposed method in that in its manufacture an amorphous aluminosilicate with a modulus of 0.6 (the molar ratio of Si/Al) was used. The catalyst according to comparative example 9 differs from the catalysts obtained according to the proposed method in that only amorphous aluminosilicate was used to prepare the binder, instead of a mixture of amorphous aluminosilicate and pseudoboehmite.

Table 1 shows the raw materials and production parameters of catalysts 1-9.

Table 2 shows the characteristics of catalysts 1-9.

Table 3 shows the characteristics of the hydrocarbon fractions of examples 10-18.

Table 4 shows the compositions of the olefin-containing fractions of examples 10-18.

Table 5 shows the conditions and main parameters of examples 10-18.

Oxygenates - as an oxygenate in examples 10-13 and 16-18 used technical methanol brand "A" GOST 2222-95. Example 15 used dimethyl ether (DME), 99%. Example 14 used 95% ethanol.

texture properties. For catalyst samples according to examples 1-9, the textural characteristics of the catalyst were determined on a Micromeritics Gemini VII 2390t instrument, before measurements, the samples were degassed at a temperature of 300°C for 4 hours.

acid properties. For the catalyst samples of Examples 1-9, the acidic properties of the samples were determined by NH ₃ TPD on a Micromeritics AutoChem HP2950 instrument. The test sample was preliminarily calcined at a temperature of 550°C for 4 hours in an air stream, then placed in a quartz reactor and kept in a nitrogen stream at 200°C for 1 hour with a purge rate of 50 ml⋅min ^-1 . Saturation was carried out in a stream of nitrogen-ammonia mixture (10.14 vol. % ammonia) at a temperature of 60°C for 30 min. Removal of physically adsorbed ammonia was carried out at 100°C in a stream of nitrogen for 30 min at a purge rate of 50 ml⋅min ^-1 . Then the sample was cooled down again and the temperature began to rise from 60°C to 750°C at a rate of 10°C⋅min ^-1 and the detector signal was recorded by thermal conductivity.

Examples 1-7 (according to the invention)

The preparation of catalysts according to examples 1-7 was carried out as follows (specific parameter values for each of examples 1-7, see Table 1).

Obtaining peptized pseudoboehmite

Peptized pseudoboehmite for examples 1-5 was obtained from thermally activated aluminum hydroxide (TCA product). To do this, thermally activated aluminum hydroxide was ground, ground thermally activated aluminum hydroxide was sent to the reactor for sodium removal. The reactor was filled with 20 l of water and 12 ml of nitric acid with a concentration of 47 wt. %. Then, 2 kg of the milled TCA product was loaded into the reactor. The suspension was heated to 70°C and stirred for 2 hours. After stirring, the suspension was filtered on a vacuum filter, after which the washing operation was repeated until pH=7. The washed and filtered aluminum hydroxide in the form of a moistened powder was sent to be loaded into an autoclave. The washed aluminum hydroxide from the filtration stage was loaded into an autoclave with stirring (THA : water ratio = 1:2 by weight, acid modulus 0.015). The autoclave was sealed, and the temperature was raised to 150°C with constant stirring. After heating, stirring of the suspension was continued at a constant temperature for 8 hours. Upon completion of the autoclaving process, the resulting pseudoboehmite suspension was transferred from the autoclave to a receiving vessel. Hydration was carried out by adding a solution of nitric acid with a concentration of 47 wt. % to a suspension of pseudoboehmite. The molar ratio of nitric acid/alumina (acid modulus) was 0.15. Hydration was carried out with stirring for 1 hour.

The peptized pseudoboehmite for Examples 6-7 was prepared from pseudoboehmite powder. Pseudoboehmite powder was peptized under stirring with an aqueous solution of nitric acid with a concentration of 3 wt. % within 30 min. The molar ratio of nitric acid/alumina (acid modulus) was 0.05.

Obtaining amorphous aluminosilicate

Amorphous aluminosilicate for examples 1-7 was obtained by co-precipitation from aqueous solutions of aluminum sulfate (with a concentration of 27 wt.%), sodium silicate (with a concentration of 23 wt.%) and ammonia (with a concentration of 25 wt.%), providing aluminosilicate with a molar Si/Al ratio ranging from 0.2 to 0.5 (see the Si/Al values according to Table 1). To do this, the aluminum hydroxide sol was precipitated from an aqueous solution of aluminum sulfate by adding an aqueous solution of ammonia at pH 9.0. The mixture was subjected to aging with stirring for 40 min at pH 9.0 and a temperature of 60°C. To the resulting suspension at a temperature of 60°C and vigorous stirring for 15 min was poured the estimated amount of an aqueous solution of sodium silicate with a mass ratio of Na/Si=0.66. By adding an aqueous solution of sulfuric acid. The pH was adjusted to 8.2, the resulting mixture was subjected to aging at 60°C for 40 minutes. The precipitation product was separated on a filter, the precipitate was repeatedly washed with distilled water until there was no sulfate anion in the washing water, which was controlled using a 2% barium chloride solution. The resulting precipitate was dried at 120°C for 12 hours. The dried aluminosilicate was ground in a mortar and calcined in a muffle at a temperature of 700°C for 10 hours at a heating rate of 5°C/min.

Catalyst production method

Peptized pseudoboehmite pulp was placed into a Z-shaped mixer, HZSM-5 was added, and mixed. The mixture was evaporated with stirring to a pasty consistency. An amorphous aluminosilicate with a Si/Al molar ratio from 0.2 to 0.5 was added to the resulting mixture. The resulting mass was evaporated to formability. As a result, a molding mass is obtained.

The resulting molding mass was molded on a granulator with a die size of 3.5–4.0 mm. The granules were dried for 12 h, dried in a convection oven, first at 80°С for 2 h, then at 120°С for 6 h. The granules were calcined in a muffle furnace at 550°С for 6 h , temperature rise 3°C/min. The result is a catalyst composition.

The obtained catalyst composition was subjected to alkali treatment. To do this, the granules of the catalyst composition were placed in a container and a sodium hydroxide solution was added (the concentration of an aqueous solution of sodium hydroxide, temperature and duration of treatment, see Table 1). Then it was filtered and washed with distilled water to remove alkali residues. The resulting granules were dried in a convection oven, first at 80°C for 2 h, then at 120°C for 6 h. /min

The catalyst composition that underwent alkaline treatment was washed from sodium by the ion exchange method. To do this, the catalyst composition was loaded into the container and an ammonium chloride solution was added (to wash 500 g of the catalyst composition, a solution of 6 g of ammonium chloride per 2.4 l of water was prepared), observing the ratio solid : liquid = 1:4 by weight. The mixture was left for 1 h without stirring at room temperature, the solution was decanted and, if necessary, repeated ion exchange and washing with water. The final content of Na ₂ O in the catalyst composition did not exceed 0.15 wt %. %. The washed catalyst composition was dried in a convection oven, first at 80°C for 2 h, then at 120°C for 6 h. Then it was calcined in a muffle furnace at 550°C for 6 h, temperature rise 3° C/min

The resulting catalyst composition was impregnated in terms of moisture capacity with solutions of zinc and rare earth elements (compositions of impregnating solutions are given in Table 1). To prepare an impregnating solution, the calculated amount of zinc nitrate was dissolved in water, REE nitrates were added in the form of a powder or in the form of an industrial concentrate of REE nitrates (for catalysts including praseodymium and neodymium) and brought to the required volume with distilled water. Impregnation was carried out once according to moisture capacity. The mixture of catalyst composition and impregnating solution was vigorously stirred for 1 hour.

Upon completion of the impregnation, the granules were dried for 30 min. The resulting impregnated granules were dried in a convection oven, first at 80°C for 2 hours, then at 120°C for 6 hours. The dried product was calcined in a muffle furnace at 550°C for 6 hours. °C/min.

The result is a catalyst.

Example 8 (comparative)

The catalyst according to example 8 was obtained similarly to examples 1-7, however, instead of amorphous aluminosilicate with a modulus of 0.2-0.5, amorphous aluminosilicate with a modulus of 0.6 (molar ratio Si/Al) was used.

Peptized pseudoboehmite for example 8 was obtained analogously to examples 1-5.

Amorphous aluminosilicate for example 8 was obtained analogously to examples 1-7.

Examples 9 (comparative)

The catalyst according to example 9 was obtained similarly to examples 1-7, however, peptized pseudoboehmite was not used in the preparation of the binder.

Amorphous aluminosilicate for example 9 was obtained analogously to examples 1-7.

Examples 10-18

For examples 10-18, a catalytic plant was used, including a catalytic reactor, automatic gas flow regulators, gas pressure reducers, a pressure regulator "to itself", a gas meter, pumps for supplying liquid raw materials, a cooled separator trap in which liquid products are collected catalysis, a cryothermostat-circulator, and an automatic temperature controller. The reactor is equipped with two channels for thermocouples, axial and near-wall. The internal diameters of the channels are 3 mm. The axial channel is used to measure the temperature along the catalyst bed, the wall channel is used to install a temperature controller thermocouple. The temperature in the reactor is controlled by a temperature controller at the point where the thermocouple is installed in the near-wall channel. The thermocouple in the near-wall channel is installed at the level of the lower boundary of the catalyst layer.

A preliminarily weighed catalyst (catalyst particle size 1–1.5 mm) was placed in a reactor between quartz layers, purged with an inert gas, after which this reactor was checked for leaks. For this, nitrogen was supplied to the stand through the reactor. The purge time was 10-15 minutes. With the help of a pressure regulator “to itself”, the working pressure was set and the reactor and the communications leading to it were checked for tightness. According to the results of the reactor tightness check, its heating was switched on. When the operating parameters of temperature and pressure were reached, liquid hydrocarbon feedstock (hydrocarbon fractions and oxygenates) was supplied to the reactor using dosing pumps. The supply of gaseous olefin-containing fractions was carried out using gas flow regulators. Liquid and gaseous products formed in the course of chemical reactions leave the reactor, are cooled in a refrigerator, pass through a pressure regulator and are collected in a cooled trap. The trap coil constantly circulates refrigerant. Circulation is carried out by a cryothermostat-circulator. Gaseous products from the trap are discharged through the gas meter to the candle. After the end of the experiment, the supply of feedstock was stopped, the pressure in the reactor was dropped to atmospheric pressure, and nitrogen was supplied to the reactor for 15-20 minutes.

Claims (23)

1. A method for producing a catalyst for the production of concentrates of aromatic compounds, including the following stages: a. adding HZSM-5 to peptized pseudoboehmite to obtain a mixture of zeolite and pseudoboehmite, b. adding an amorphous aluminosilicate with a Si/Al molar ratio of 0.2 to 0.5 to the mixture obtained in step (a) to obtain a molding composition, c. molding, drying and calcining the molding mass to obtain a catalyst composition, d. alkaline treatment of the catalyst composition obtained in step (c), e. washing from sodium the catalyst composition obtained in stage (d), drying and calcining, f. impregnation of the catalyst composition obtained in stage (e) with solutions of zinc salts and rare earth elements, drying and calcination to obtain the following chemical composition in terms of catalyst oxides: i. silicon dioxide in an amount of from 53.0 to 85.0 wt. %, ii. aluminum oxide in an amount from 11.5 to 43.0 wt. %, iii. zinc oxide in an amount of 1.4 to 2.9 wt. %, iv. oxides of rare earth elements in an amount of 0.9 to 2.0 wt. %. 2. The method according to claim 1, wherein the alkaline treatment uses an aqueous alkali solution with a pH of 10 to 14, preferably a pH of 12 to 14. 3. The method according to p. 1, in which an aqueous solution of sodium hydroxide with a concentration of 0.01-0.5 M is used for alkaline treatment. 4. The method according to p. 1, in which the alkaline treatment is carried out by heating to 30-80°C. 5. The method of claim. 1, in which impregnation of the catalyst composition using moisture capacity impregnation or impregnation in excess solution. 6. The method according to p. 1, in which the resulting catalyst includes zeolite ZSM-5 in an amount of from 50.0 to 85.0 wt. %, where a. the pore volume of the catalyst is from 0.15 to 0.29 cm ³ /g, b. the average pore diameter of the catalyst is from 38 to 55

, c. the ratio of weak and strong acid sites of the catalyst is from 1.2 to 2.5. 7. The method according to claim 1, in which the resulting catalyst is used for the co-processing of hydrocarbon fractions, oxygenates and olefin-containing fractions into aromatics concentrates, preferably the catalyst is used for a process for producing aromatics concentrates, in which three streams are used as feedstock, one of which includes a hydrocarbon fraction, the second stream includes an oxygenate, the third stream includes an olefin-containing fraction, where the olefin-containing fraction includes one or more olefins selected from the group including: ethylene, propylene, normal butylenes, isobutylene, in a total amount of 10.0 up to 50.0 wt. %. 8. The method of claim. 1, in which the rare earth elements include one or more elements selected from the group including: lanthanum, praseodymium, neodymium, cerium. 9. The method according to p. 1, in which the obtained catalyst does not contain one or more elements selected from the group including: platinum metals, iron, cobalt, nickel. 10. The method according to claim 1, wherein the zeolite has a silica module SiO ₂ /Al ₂ O ₃ in the range from 50 to 90, preferably from 60 to 80.