RU2789407C1 - Micro-spherical catalyst for increasing yield of catalytic cracking gasoline and method for its preparation - Google Patents

Abstract

FIELD: oil refining industry.

SUBSTANCE: micro-spherical catalyst for increasing the yield of catalytic cracking gasoline is described, including ultra-stable zeolite Y in a cation-decationized form and a matrix consisting of amorphous aluminosilicate, aluminum oxide, and kaolin clay, in which amorphous aluminosilicate modified with boron compounds is used as a matrix component, containing 1-5 wt.% of boron, with the following ratio of components in the catalyst, wt.%: zeolite Y 18-25; amorphous aluminosilicate 30-40; aluminum oxide 20-30; kaolin clay 15-22. A method for the preparation of a micro-spherical catalyst for increasing the yield of catalytic cracking gasoline is described, including ion exchanges for cations of rear earth elements and ammonium on zeolite NaY, two-stage ultra-stabilization of zeolite, mixing of zeolite with the matrix, as components of which amorphous aluminosilicate, aluminum oxide, and kaolin clay are used, spray drying of the resulting composition with subsequent calcination and obtainment of the catalyst. At the same time, amorphous aluminosilicate, during synthesis, is modified with boron compounds until boron content of 1-5 wt.% by mixing of liquid glass solutions and a mixture of aluminum sulfate and sulfuric acid with addition of boric acid, or with mixing liquid glass solutions with addition of ammonium tetraborate, ammonium sulfate, and sulfuric acid. In this case, liquid glass solutions are used with a concentration of 1.2-1.5 N and a module (molar ratio of silicon and sodium oxide) equal to 2.4-3.1, as well as aluminum sulfate with a concentration by aluminum oxide of about 20-40 g/dm³, with the following ratio of components in the catalyst, wt.%: zeolite Y 18-25; amorphous aluminosilicate 30-40; aluminum oxide 20-30; kaolin clay 15-22.

EFFECT: obtainment of a cracking catalyst providing an increase in the yield and selectivity of gasoline formation.

2 cl, 2 tbl, 7 ex

Description

The present invention relates to the oil refining industry, and in particular to a method for the preparation of catalysts for the cracking of petroleum fractions.

Cracking catalysts consist of the main active component of zeolite Y and a matrix, which includes a binder and a filler. Natural clays are used as a filler. Amorphous aluminosilicate is used as a binder.

The involvement of natural clays in the composition of cracking catalysts is the practice of all companies in the world. The main function of the involvement of natural clays in the composition of cracking catalysts is the formation of a wide-pore structure of the catalyst to ensure the diffusion of reagents to the active centers of the catalyst. In addition, the involvement of natural clays should provide high mechanical abrasion resistance (wear resistance) of the microspherical cracking catalyst.

In addition, the creation of a wide-pore structure of the catalyst is facilitated by the modification of amorphous aluminosilicate in order to increase its pore size.

и содержанием редкоземельных элементов 3,0-6,0 мас. %, цеолит HZSM-5 с кремнеземным модулем от 25 до 40 и матрицу, в качестве компонентов которой используют бентонитовую глину, гидроксид алюминия и аморфный алюмосиликат. Катализатор содержит, в мас. %: цеолит Y 15-25; цеолит HZSM-5 1-5; бентонитовую глину 15-30; гидроксид алюминия 15-30; аморфный алюмосиликат 20-45.A microspherical catalyst is known for simultaneously increasing the yield of gasoline and the octane number of gasoline for cracking vacuum gas oil and a method for its preparation (patent RU2473384). The catalyst includes an ultra-stable Y zeolite with a lattice constant of 24.30 to 24.55

and the content of rare earth elements 3.0-6.0 wt. %, HZSM-5 zeolite with a silica module from 25 to 40 and a matrix, the components of which are bentonite clay, aluminum hydroxide and amorphous aluminosilicate. The catalyst contains, in wt. %: zeolite Y 15-25; zeolite HZSM-5 1-5; bentonite clay 15-30; aluminum hydroxide 15-30; amorphous aluminosilicate 20-45.

, проведение ионных обменов на катионы аммония и редкоземельных элементов на цеолите Y до содержания редкоземельных элементов в цеолите 3,0-6,0 мас. %, аммония 7,0-8,0%, ультрастабилизацию цеолита в среде водяного пара, после ультрастабилизации проводят третий ионный обмен на катионы аммония и последующее смешение цеолита с компонентами матрицы.The method for preparing the above catalyst includes the use of Y zeolite with a lattice constant of 24.30 to 24.55

, carrying out ion exchanges for ammonium cations and rare earth elements on zeolite Y to the content of rare earth elements in the zeolite 3.0-6.0 wt. %, ammonium 7.0-8.0%, ultra-stabilization of the zeolite in a water vapor medium, after ultra-stabilization, a third ion exchange for ammonium cations is carried out and subsequent mixing of the zeolite with the matrix components.

A known method of converting hydrocarbons into olefins and aromatic hydrocarbons and a method of obtaining a catalytic composition for its implementation (patent RU2199573). The process includes reacting a hydrocarbon stream with a catalyst composition under conditions sufficient to effect conversion of the hydrocarbon to olefins and C ₆ -C ₈ aromatics. The catalytic composition includes a zeolite, a binder and boron, where the mass of boron is in the range of 0.01-10 wt. %. Also described is a process for preparing a catalyst composition that includes (1) mixing a zeolite with a coke-reducing amount of a binder under conditions effective to obtain a zeolite-binder mixture; (2) reacting said zeolite-binder mixture with a coke-reducing amount of a boron compound under conditions effective to produce a boron-infused zeolite or boron-impregnated zeolite, and (3) calcining the boron-infused zeolite or boron-impregnated zeolite.

The disadvantage of the above catalysts and methods for their production are not sufficiently high yield and selectivity of the formation of gasoline.

Known catalyst for catalytic cracking of hydrocarbon oil products, its production and use (patent RU2471553). The catalyst includes a matrix containing alumina and a molecular sieve and has the following pore distribution: 5-70% of pores are <2 nm pores, 5-70% of pores are 2-4 nm pores, 0-10% of pores are 4-6 nm, 20-80% of pores - pores of 6-20 nm in size and 0-40% of pores - pores of 20-100 nm in size, based on the volume of pores with a size of not more than 100 nm. In the method for producing a catalyst, the following steps are performed: a matrix containing alumina and/or its precursors is mixed with a molecular sieve, suspended and the mixture is dried by spray drying, while a pore expander is introduced at the mixing stage, while the pore expander can be selected from a group comprising boric acid and alkali metal salts, wherein the weight ratio of the pore expander to the matrix is 0.1:100-15:100 by weight of the matrix. A method for catalytic cracking using the catalyst described above is described. EFFECT: the catalyst has a large pore volume determined by the BET method, a high ability to crack heavy oil products and high resistance to coking. The disadvantage of this method is not enough high yield of gasoline.

Known catalyst for catalytic cracking of hydrocarbons rich in naphthenic cyclic hydrocarbons, method of its production and method of application (patent CN111822033). The catalyst includes natural minerals, a boron-aluminum-silicon composite oxide, an inorganic oxide binder, a Y-type molecular sieve, and a selective shape molecular sieve. The preparation method includes the following steps: preparing a boron-aluminum-silicon composite oxide, forming a suspension containing a boron-aluminum-silicon composite oxide, a molecular sieve, a natural mineral substance, a binder based on an inorganic oxide and water, and carrying out spray drying, where the production method The composite boron-aluminum-silicon oxide includes the steps of mixing an alumina precursor, a boron precursor and water, adding an acid, acidifying to obtain a mixture, mixing the mixture with a silicon precursor, drying and calcining. The catalytic cracking catalyst has a relatively high naphthenic cyclic cracking activity, is used to convert hydrocarbon feedstock rich in naphthenic cyclic hydrocarbons, and has a relatively high yield of ethylene and propylene. The disadvantage of this method are not enough high yield of gasoline.

Closest to the proposed catalyst is a microspherical catalyst for the cracking of petroleum fractions (patent RU2673811). The catalyst includes ultrastable zeolite Y in cation-decation form and a matrix, the components of which are amorphous aluminosilicate, alumina and natural clay, and is characterized in that it contains kaolin clay modified with sodium polyphosphate as a matrix component in the following ratio of components in the catalyst, wt . %: zeolite Y 18-25; amorphous aluminosilicate 20-40; aluminum oxide 10-40; kaolin clay 10-30.

Closest to the proposed method is a method for preparing a microspherical catalyst for cracking petroleum fractions (patent RU2673813), including ion exchange for cations of rare earth elements and ammonium on NaY zeolite, two-stage ultra-stabilization of the zeolite, mixing the zeolite with a matrix, the components of which are amorphous aluminosilicate, aluminum oxide and natural clay, spray drying of the resulting composition, followed by calcination and obtaining a catalyst. As a matrix component, kaolin clay is used, which is preliminarily modified with sodium polyphosphate in an amount of 0.1-0.3 wt. % for 3-6 hours, and then subjected to a two-stage dispersion, obtaining a catalyst containing, wt. %: zeolite Y 18-25; amorphous aluminosilicate 20-40; aluminum oxide 10-40; kaolin clay 10-30. The yield of gasoline when using a known catalyst and this method of obtaining a catalyst is also insufficient.

The technical result of the present invention is to obtain a cracking catalyst that provides an increase in the yield and selectivity of the formation of gasoline.

The technical result is achieved by using a wide-pore aluminosilicate and thereby improving the porous structure of the catalyst as a whole.

The proposed microspherical catalyst for increasing the yield of catalytic cracking gasoline and the selectivity of its formation includes ultrastable Y zeolite in cation-decation form and a matrix consisting of amorphous aluminosilicate, aluminum oxide and kaolin clay, and is characterized in that amorphous boron modified with boron compounds is used as a matrix component. aluminosilicate containing 1-5 wt. % boron, with the following ratio of components in the catalyst, wt. %: zeolite Y 18-25; amorphous aluminosilicate 30-40; aluminum oxide 20-30; kaolin clay 15-22.

The proposed method for preparing a microspherical catalyst for increasing the yield of catalytic cracking gasoline includes carrying out ion exchanges for rare earth and ammonium cations on NaY zeolite, two-stage ultra-stabilization of the zeolite, mixing the zeolite with a matrix, the components of which are amorphous aluminosilicate, aluminum oxide and kaolin clay, spray drying the resulting composition, followed by calcination and obtaining a catalyst, while the amorphous aluminosilicate is modified with boron compounds to a content of 1-5 wt. % boron.

The method of preparation of the catalyst is carried out as follows. Zeolite NaY is subjected to four ion exchanges for cations of rare earth elements and ammonium, two-stage ultra-stabilization of the zeolite is carried out to obtain a lattice modulus of the zeolite in the range from 7 to 10 and a residual content of sodium oxide in the zeolite is not more than 0.5 wt. %. The finished zeolite is mixed with the components of the catalyst matrix, which are used as suspensions of amorphous aluminosilicate with a boron oxide content of 1-5 wt. %, aluminum oxide and kaolin clay. Pre-natural kaolin clay is modified by hydration in the presence of sodium polyphosphate, and then subjected to a two-stage dispersion so that the average particle size of kaolin is less than 7 microns.

The preparation of amorphous aluminosilicate as a component of a zeolite-containing cracking catalyst is carried out by co-precipitation of silicon and aluminum oxides from solutions of sodium silicate and aluminum sulfate, mixed in a certain ratio. This cooking method includes several stages:

1. Obtaining a hydrosol by mixing solutions of liquid glass, aluminum sulfate and sulfuric acid;

2. Sol gelling;

3. Syneresis process, regulation of porous structure;

4. Activation with aluminum sulfate and washing to remove sodium ions and excess anion.

According to the invention, two boron compounds are used as the initial boron-containing compound:

- boric acid, which is added to a mixture of aluminum sulfate and sulfuric acid;

- ammonium tetraborate, which is added to liquid glass.

It is also possible to use other sources of boron that achieve a similar effect, for example, the introduction of boron from synthetic aluminoborate in the preparation of aluminosilicate.

Two methods are used for the precipitation of aluminosilicate. According to the first method, a hydrosol is obtained by mixing solutions of liquid glass and aluminum sulfate and sulfuric acid with the addition of boric acid so that the boron content during precipitation is from 1 to 5 wt. %. According to the second method, the hydrosol is obtained by mixing solutions of liquid glass with the addition of ammonium tetraborate, aluminum sulfate and sulfuric acid so that the boron content during precipitation is 3 wt. %.

For the synthesis of amorphous aluminosilicate, solutions of liquid glass with a concentration of 1.2-1.5 N and a modulus (molar ratio of silicon and sodium oxides) equal to 2.4-3.1, and aluminum sulfate with an aluminum oxide concentration of about 20-40 g / dm ³ . If necessary, add the calculated amount of sulfuric acid to a solution of aluminum sulfate. The deposition of aluminosilicate by both methods is carried out at a temperature of the initial solutions from 10 to 12°C.

The syneresis of the precipitated aluminosilicate is carried out at a temperature of 26-27°C, gel pH values from 8.5 to 9.5 units for 4 to 6 hours.

The activation of the aluminosilicate and its washing is carried out until the residual content of sodium oxide in the finished aluminosilicate is less than 0.2 wt. %, which is a typical and regulated practice in the technological process of catalyst production.

The resulting finished aluminosilicate is mixed with other catalyst components, and the resulting suspension of the catalyst composition is subjected to molding by spray drying and calcining at high temperature.

The distribution of pore volume by size of the finished calcined aluminosilicates is determined by the method of low-temperature adsorption of nitrogen from its adsorption-desorption isotherms. Nitrogen adsorption–desorption isotherms were measured by the multipoint method at 77.4 K on a volumetric vacuum static setup ASAP-2020M Micromeritics, USA.

To obtain differential characteristics of mesopore size distribution curves (dV/dD, cm ³ /g⋅nm), the Barrett-Joyner-Halenda method (BJH method) is used for the adsorption and desorption branches of isotherms. From the distribution curves of pore volume by size (dV/dD vs. D), the average pore diameter (D _des , for the desorption branch of the isotherm) is calculated.

Catalytic tests of the prepared catalysts are carried out on a laboratory unit of the flow type MAK-2M, corresponding to the ASTM D 3907 standard, with a fixed catalyst bed. The reactor system was purged with nitrogen at a rate of 30 ml/min. The catalyst is loaded in the amount of 5 g. The hydrocarbon feedstock is dosed within 30 seconds. The activity is evaluated as the degree of conversion of the feedstock under the given standard conditions. The selectivity of the formation of gasoline is calculated as the ratio of the yield of gasoline to the degree of conversion of raw materials. The catalysts are treated with 100% steam at 788°C for 5 hours before testing. The gasoline fraction includes all hydrocarbons that boil up to 216°C.

The properties of vacuum gas oil used for testing catalysts are shown in Table 1.

The composition and properties of the obtained catalysts, as well as the test results are shown in Table 2.

The essence of the invention is illustrated by the following examples.

Example 1 (prototype, comparative).

The NaY zeolite is subjected to a double ion exchange for ammonium cations to obtain a residual sodium oxide content in the zeolite of less than 4.5 wt. %. Next, the zeolite is subjected to ultra-stabilization in a steam environment to achieve a lattice modulus of the zeolite equal to 7. Next, the zeolite is subjected to ion exchange for ammonium and rare-earth cations to obtain a residual sodium oxide content in the zeolite of less than 1.4 wt. %, and subjected to ultra-stabilization in steam to achieve a lattice modulus of the zeolite equal to 9. Then the zeolite is subjected to ion exchange for ammonium cations to obtain a residual content of sodium oxide in the zeolite less than 0.5 wt. %.

Kaolin clay is prepared as follows. Sodium tripolyphosphate is dissolved in water at the rate of 0.2 wt. % on absolutely dry clay, modification is carried out by hydration of kaolin clay in water with dissolved sodium tripolyphosphate at a weight ratio of clay: water equal to 1:10 for 6 hours at a temperature of 20°C.

The preparation of amorphous aluminosilicate as a component of a zeolite-containing cracking catalyst is carried out by co-precipitation of silicon and aluminum oxides from solutions of sodium silicate and aluminum sulfate, mixed in a certain ratio. This cooking method includes several stages:

1. Obtaining a hydrosol by mixing solutions of liquid glass, aluminum sulphate and sulfuric acid;

2. Sol gelling;

3. Syneresis process to regulate the pore structure;

4. Activation with aluminum sulfate and washing to remove sodium ions and excess anion.

For the synthesis of amorphous aluminosilicate, solutions of liquid glass with a concentration of 1.5 N and a modulus (molar ratio of silicon and sodium oxides) equal to 2.9 and aluminum sulfate with an aluminum oxide concentration of about 30 g/dm ³ are used. If necessary, the calculated amount of sulfuric acid was added to the SCA solution to achieve precipitation pH values of 7 units. The deposition of aluminosilicate by both methods is carried out at a temperature of the initial solutions from 10 to 12°C.

The syneresis of the precipitated aluminosilicate is carried out at a temperature of 26-27°C, gel pH values of 9.5 units for 4 hours.

The activation of the aluminosilicate and its washing is carried out until the residual content of sodium oxide in the finished aluminosilicate is less than 0.2 wt. %. The obtained aluminosilicate after calcination at 700°C has an average pore diameter of 3.0 nm and a pore volume of 0.320 cm ³ /g.

Suspensions of the resulting zeolite, kaolin clay, alumina and amorphous aluminosilicate are mixed in such proportions that the catalyst composition in terms of absolutely dry matter has the following component composition, wt. %:

zeolite - 20

aluminum oxide - 20

kaolin clay - 22

amorphous aluminosilicate - 38.

The resulting suspension is molded into a microspherical shape by spray drying. The microspherical granules of the dry catalyst are calcined at a temperature of 720°C.

The resulting catalyst has an insufficiently high yield and selectivity for the formation of gasoline.

Example 2

Characterizes the claimed method of preparing the catalyst. The difference from example 1 is the use of aluminosilicate catalyst, which is prepared as follows. For the synthesis of amorphous aluminosilicate, solutions of liquid glass with a concentration of 1.5 N and a modulus (molar ratio of silicon and sodium oxides) equal to 2.9 and aluminum sulfate with an aluminum oxide concentration of about 30 g/dm ³ are used. Boric acid is added to a solution of aluminum sulphate with sulfuric acid so that the boron content during the precipitation of aluminosilicate is 1 wt. %. The obtained aluminosilicate after calcination at 700°C has an average pore diameter of 5.0 nm and a pore volume of 0.386 cm ³ /g.

Suspensions of the resulting zeolite, kaolin clay, alumina and amorphous aluminosilicate are mixed in such proportions that the catalyst composition in terms of absolutely dry matter has the following component composition, wt. %:

zeolite - 20

aluminum oxide - 20

kaolin clay - 22

amorphous aluminosilicate - 38.

The resulting suspension is molded into a microspherical shape by spray drying. The microspherical granules of the dry catalyst are calcined at a temperature of 720°C.

The resulting catalyst has an increased yield and selectivity for the formation of gasoline.

Example 3

Similar to example 2, but during the precipitation of aluminosilicate with the introduction of boric acid, the boron content during the precipitation of aluminosilicate is 3.34 wt. %. The obtained aluminosilicate after calcination at 700°C has an average pore diameter of 6.8 nm and a pore volume of 0.638 cm ³ /g.

Suspensions of the resulting zeolite, kaolin clay, alumina and amorphous aluminosilicate are mixed in such proportions that the catalyst composition in terms of absolutely dry matter has the following component composition, wt. %:

zeolite - 20

aluminum oxide - 20

kaolin clay - 20

amorphous aluminosilicate - 40.

The resulting catalyst has a high yield and selectivity for the formation of gasoline.

Example 4

Similar to example 2, but during the deposition of aluminosilicate with the introduction of boric acid, the boron content during the deposition of aluminosilicate is 5.0 wt. %. The obtained aluminosilicate after calcination at 700°C has an average pore diameter of 7.0 nm and a pore volume of 0.565 cm ³ /g.

Suspensions of the resulting zeolite, kaolin clay, alumina and amorphous aluminosilicate are mixed in such proportions that the catalyst composition in terms of absolutely dry matter has the following component composition, wt. %:

zeolite - 25

aluminum oxide - 25

kaolin clay - 20

amorphous aluminosilicate - 30.

The resulting catalyst has a high yield and selectivity for the formation of gasoline.

Example 5

Similar to example 4, but the composition of the catalyst in terms of absolutely dry matter has the following component composition, wt. %:

zeolite - 18

aluminum oxide - 30

kaolin clay - 22

amorphous aluminosilicate - 30.

Example 6

Similar to example 2, but during the deposition of aluminosilicate with the introduction of ammonium tetraborate into liquid glass, the boron content during the deposition of aluminosilicate is 3.0 wt. %. The obtained aluminosilicate after calcination at 700°C has an average pore diameter of 6.5 nm and a pore volume of 0.527 cm ³ /g.

The composition of the catalyst in terms of absolutely dry matter has the following composition, wt. %:

zeolite - 20

aluminum oxide - 20

kaolin clay - 22

amorphous aluminosilicate - 38.

Example 7

Similar to example 3, but the composition of the catalyst in terms of absolutely dry matter has the following component composition, wt. %:

zeolite - 20

aluminum oxide - 25

kaolin clay - 15

amorphous aluminosilicate - 40.

Thus, as follows from the examples and the table, by the proposed method of preparation, a cracking catalyst was obtained, providing an increased yield of gasoline and the selectivity of its formation.

Claims (2)

1. A microspherical catalyst for increasing the yield of catalytic cracking gasoline, including ultrastable zeolite Y in cation-decation form and a matrix consisting of amorphous aluminosilicate, aluminum oxide and kaolin clay, in which amorphous aluminosilicate modified with boron compounds containing 1- 5 wt. % boron, with the following ratio of components in the catalyst, wt. %: zeolite Y 18-25; amorphous aluminosilicate 30-40; aluminum oxide 20-30; kaolin clay 15-22. 2. A method for preparing a microspherical catalyst to increase the yield of catalytic cracking gasoline, including ion exchange for cations of rare earth elements and ammonium on NaY zeolite, two-stage ultra-stabilization of the zeolite, mixing the zeolite with a matrix, the components of which are amorphous aluminosilicate, aluminum oxide and kaolin clay, spray drying of the resulting composition, followed by calcination and obtaining a catalyst, characterized in that the amorphous aluminosilicate during synthesis is modified with boron compounds to a boron content of 1-5 wt. % by mixing solutions of liquid glass and a mixture of aluminum sulphate and sulfuric acid with the addition of boric acid or by mixing solutions of liquid glass with the addition of ammonium tetraborate, ammonium sulphate and sulfuric acid, and using solutions of liquid glass with a concentration of 1.2-1.5 N and module (molar ratio of oxides of silicon and sodium), equal to 2.4-3.1, and aluminum sulfate with a concentration of aluminum oxide of about 20-40 g/DM ³ in the following ratio of components in the catalyst, wt. %: zeolite Y 18-25; amorphous aluminosilicate 30-40; aluminum oxide 20-30; kaolin clay 15-22.