Catalyst and method of preparing same

Abstract

A catalyst for increasing the yield of light olefins in the process of catalytic cracking contains a phosphorous-modified MFI-type zeolite, ultrastable Y zeolite and a matrix consisting of an amorphous aluminosilicate, aluminium oxide and natural clay. The MFI-type zeolite has a Si / Al ratio of from 15 to 40 and the ultrastable Y zeolite contains from 0.7 to 4.0 wt.% rare-earth element oxides. The catalyst contains: 7-20 wt.% phosphorous-modified MFI-type zeolite, 10-17 wt.% ultrastable Y zeolite, 19-22 wt.% natural clay, 28-35 wt.% amorphous aluminosilicate, 19-28 wt.% aluminium oxide. Also claimed is a method of preparing the catalyst. The technical result consists in an increase in light olefin yield, together with high feedstock conversion rates.

Description

[0001] CATALYST AND METHOD OF ITS PREPARATION

[0002] The group of inventions relates to the oil refining and petrochemical industries, namely to the preparation of a catalyst for increasing the yield of light olefins in the process of catalytic cracking of vacuum gas oils of varying quality.

[0003] Over the past 40 years, a wide variety of catalysts have been used, allowing for varying the composition of process products from vacuum gas oils of varying quality without changing the unit design. One way to increase the selectivity for light olefin formation in catalytic cracking is to use a catalyst composition typically containing a phosphorus-modified MFI zeolite, also known as ZSM-5, which selectively converts the primary cracking products (gasoline fraction) into light olefins (Cr-C4).

[0004] A hydrocarbon cracking catalyst is known, containing 20-50 wt.% ZSM-5 zeolite, 10-45 wt.% clay, 10-45 wt.% inorganic oxide, 1-10 wt.% one or more metals, and 5-15 wt.% phosphorus for increasing the yield of liquefied gases, in which the ZSM-5 zeolite is modified with phosphorus (patent RU 2397811). A disadvantage of this catalyst is the low yield of cracked gasoline.

[0005] A hydrocarbon cracking catalyst used in the production of light olefins is based on a ZSM-5 zeolite, natural clay, and an inorganic oxide with the addition of manganese oxide and phosphorus (patent RU 2494809). The phosphorus precursor is added to the catalyst composition or its components. Another drawback of this catalyst is its low yield of cracked gasoline.

[0006] US Patents 7,507,685, 7,674,942, 7,662,737, and 8,062,987 disclose a zeolite catalyst obtained by treating zeolite with a phosphorus compound. The resulting P-treated zeolite was heated to a temperature of 300°C or higher to form a zeolite-binder mixture and then combined with an inorganic oxide-based binder. The zeolite-binder mixture was heated to a temperature of approximately 400°C or higher to form a binder for the zeolite catalyst. The binder material is an alumina-containing material. A disadvantage of these inventions is the low activity of the catalysts.

[0007] A catalyst composition comprising rare earth exchanged zeolite Y (REUSY), pentasil zeolite, a phosphorus compound, clay, silica, alumina, and spinel is known for enhancing catalytic activity and selectivity for light olefins under FCC operating conditions (US Patent No. 10,894,248). The present invention also relates to a method for preparing a catalyst composition that improves light olefin content, with high propylene yield and coke selectivity. A disadvantage of this catalyst is its low yield of cracked gasoline.

[0008] The closest to the proposed invention in purpose and composition is a catalyst for the joint cracking of petroleum fractions (patent RU 2709522), including zeolite ZSM-5, ultrastable zeolite HP33Y and a matrix consisting of amorphous aluminosilicate, aluminum oxide and bentonite clay, where zeolite ZSM-5 has a Si / Al ratio from 30 to 80, contains from 2.0 to 4.0 wt. % phosphorus, with the following ratio of components in the catalyst, wt. %: phosphorus-modified zeolite ZSM-5 8-20; ultrastable zeolite HP33Y 15-25; aluminum oxide from reprecipitated hydroxide 15-30; bentonite clay 15-30 and amorphous aluminosilicate 16-30. The disadvantage of this method is the low conversion of unhydrotreated vacuum gas oil and the low yield of light olefins. Furthermore, the high content of expensive ZSM-5 zeolite is a drawback of this method.

[0009] The technical result of the invention group is the production of a catalyst for cracking vacuum gas oils of various qualities to increase the yield of light olefins at high feedstock conversion values.

[0010] The technical result is achieved in that the catalyst for increasing the yield of light olefins in the catalytic cracking process includes a phosphorus-modified MFI type zeolite, an ultrastable Y zeolite and a matrix consisting of amorphous aluminosilicate, aluminum oxide and natural clay, wherein the MFI type zeolite has a Si / Al ratio from 15 to 40, the ultrastable Y zeolite contains from 0.7 to 4.0 wt. % of rare earth element oxides, with the following content of components in the catalyst, wt. %: phosphorus-modified MFI type zeolite -5 7-20; ultrastable Y zeolite 10-17; natural clay 19-22; amorphous aluminosilicate 28-35; aluminum oxide 19-28. In one embodiment of the invention, the MFI type zeolite contains from 2.0 to 6.0 wt. % phosphorus.

[0011] In one embodiment of the invention, aluminum oxide from the product of thermochemical activation of alumina and kaolin clay are used as matrix components.

[0012] Also, the technical result is achieved in that the method for preparing a catalyst for increasing the yield of light olefins in the catalytic cracking process includes mixing ultrastable zeolite Y and a phosphorus-modified MFI zeolite with matrix components consisting of amorphous aluminosilicate, aluminum oxide and natural clay, spray drying the resulting composition with subsequent calcination, wherein the modification of the MFI zeolite is carried out by impregnation with phosphoric acid or urea phosphate, with a Si / Al ratio from 15 to 40, the ultrastable zeolite Y is obtained by ion exchange for cations of rare earth elements and ammonium with a content of oxides of rare earth elements from 0.7 to 4.0 wt. %, with the following content of components in the catalyst, wt. %: phosphorus-modified MFI zeolite 7-20; ultrastable zeolite Y 10-17; natural clay 19-22; amorphous aluminosilicate 28-35; aluminum oxide 19-28.

[0013] In one embodiment of the invention, impregnation with phosphoric acid or urea phosphate is carried out until the phosphorus content is from 2.0 to 6.0 wt.%.

[0014] In one embodiment, aluminum oxide is obtained by processing the product of thermochemical activation of alumina.

[0015] Preferably, kaolin clay is used as natural clay.

[0016] Aluminum oxide in additives can be obtained from a TCA product modified with a mixture of H2SO4 and HNO3 acids at a temperature of 40-60°C during the hydration stage and at a temperature of 140-160°C during the hydrothermal treatment stage. It can also be obtained from reprecipitated aluminum hydroxide modified with nitric acid HNO3 at a temperature of 40-60°C.

[0017] Ultra-stable zeolite Y is obtained by ion exchanges with cations of rare earth element (REE) oxides and ammonium with intermediate two stages of ultra-stabilization.

[0018] The catalyst is prepared by sequentially mixing suspensions of its constituent components: 1) preparation of the aluminum-containing component by mixing suspensions of natural clay and aluminum oxide in the required ratio;

[0019] 2) introduction of a suspension of modified MFI type zeolite and ultra-stable Y zeolite, as well as a suspension of amorphous aluminosilicate, into the suspension of the aluminum-containing component.

[0020] The primary requirement for all stages of catalyst composition preparation is homogeneous mixing of the component suspensions. The resulting catalyst composition is molded. The catalyst is then dried first in air at room temperature, then at 100°C, and calcined at 600°C. To assess the stable activity of the additive, samples are treated in a 100% water vapor environment at 788°C for 5 hours in accordance with ASTM D 4463.

[0021] Catalytic tests were performed on a laboratory fixed-bed setup for testing microspherical cracking catalysts. The tests were conducted in accordance with ASTM D 3907. The cracking temperature was 527°C, the catalyst-to-feedstock ratio was 4, and the feedstock weight velocity was 30 h . 1 .

[0022] Gaseous products were analyzed on gas chromatographs “Chromatec-Crystal 5000.2” and “Chromatec-Lux 4000M”, equipped with a capillary column HP-A1 / S (50 m x 0.537 mm x 15.00 μm, stationary phase HP-A1 / S) and a flame ionization detector for analyzing the hydrocarbon component of the gas, as well as a packed column (3 m x 2 mm, NaX adsorbent fraction 80 / 100 mesh) and a thermal conductivity detector for determining the content of inorganic gases (nitrogen, hydrogen sulfide). The fractional composition of liquid products was determined by simulated distillation according to ASTM D 2887 on a Chromatec-Crystal 5000.2 instrument equipped with a DB-2887 capillary column (10 m x 0.530 mm x 3.00 μm, dimethylpolysiloxane stationary phase) and a flame ionization detector. The coke content of the catalyst was determined by the mass loss upon calcination in air at 550 °C.

[0023] Catalyst tests were carried out during the conversion of hydrotreated (HTVG) and non-hydrotreated (NHTVG) vacuum gas oils, the main characteristics of which are given in Table 1. Table 1

[0024]

[0025] The composition of the catalysts and the test results are given in Table 2.

[0026] The essence of the invention is illustrated by the following examples.

[0027] Example 1 (comparative to prototype).

[0028] The preparation of a phosphorus-modified MFI zeolite with a Si / Al ratio of 30 is carried out by impregnating the MFI zeolite with a solution of (TCH2HPO4). The impregnated zeolite is separated from the mother liquor, dried in air for 24 hours at room temperature, then at 100°C for 10 hours, and calcined at 600°C for 5 hours. The catalyst is prepared by mixing the phosphorus-modified MFI zeolite with suspensions of zeolite Y, bentonite clay, reprecipitated aluminum hydroxide, and amorphous aluminosilicate, followed by molding, drying the catalyst at 100°C for 12 hours, and calcining in air at 600°C for 5 hours. The catalyst contains, wt.%: zeolite Y with a REE oxide content of 6 wt.% - 15; phosphorus-modified MFI zeolite with a content of phosphorus 2% - 20, aluminum oxide from precipitated hydroxide 20, bentonite clay 20 and amorphous aluminosilicate 25. Non-hydrotreated vacuum gas oil is subjected to cracking.

[0029] Example 2 (comparative to prototype).

[0030] Similar to example 1, differs in that the catalyst is tested in the cracking of hydrotreated vacuum gas oil.

[0031] Example 3.

[0032] Similar to Example 1, the difference is that the phosphorus-modified MFI zeolite is produced by impregnating an MFI zeolite with a Si / Al ratio of 15 with a phosphoric acid solution. Another difference is the use of aluminum oxide obtained from a TCA product and kaolin clay in the matrix. Example 4.

[0033] Similar to example 3, the difference is that the catalyst mixture is tested in the cracking of hydrotreated vacuum gas oil.

[0034] Example 5.

[0035] Similar to example 3, the difference is that the production of phosphorus-modified MFI zeolite is carried out at a Si / Al ratio of 40, with a phosphorus content of 4.0 wt.%, zeolite Y contains 0.7 wt.% of rare earth oxides, with the following content of catalyst components in wt.%: phosphorus-modified MFI type zeolite 7; ultrastable zeolite Y 17; kaolin clay 22; amorphous aluminosilicate 35; aluminum oxide 19. Hydrotreated vacuum gas oil is subjected to cracking.

[0036] Example 6.

[0037] Similar to example 5, the difference is that the production of phosphorus-modified MFI type zeolite is carried out by impregnating the MFI type zeolite with a urea phosphate solution; zeolite Y contains 3.0 wt. % REE oxides.

[0038] Example 7.

[0039] Similar to Example 5, the difference is that zeolite Y contains 4.0 wt.% REE oxides. Another difference is the use of bentonite clay in the matrix.

[0040] Example 8.

[0041] Similar to example 5, the difference is that non-hydrotreated vacuum gas oil is cracked. Another difference is the use of aluminum oxide in the matrix, obtained from reprecipitated aluminum hydroxide.

[0042] Example 9.

[0043] Similar to example 8, the difference is that zeolite Y contains 3.0 wt. % REE oxides.

[0044] Example 10.

[0045] Similar to Example 8, the difference is that the phosphorus-modified MFI zeolite is produced by impregnating the zeolite with a urea phosphate solution, while zeolite Y contains 4.0 wt.% REE oxides. Another difference is the use of aluminum oxide obtained from reprecipitated aluminum hydroxide in the matrix.

[0046] Example 11. Similar to example 5, the difference is that the production of phosphorus-modified MFI type zeolite is carried out at a Si / Al ratio of 15, zeolite Y contains 3.0 wt. % of rare earth oxides, with the following content of catalyst components by weight: phosphorus-modified MFI type zeolite 15; ultrastable zeolite Y 10; kaolin clay 20; amorphous aluminosilicate 35; aluminum oxide 20. Hydrotreated vacuum gas oil is subjected to cracking.

[0047] Example 12.

[0048] Similar to Example 11, the difference is that the phosphorus-modified MFI zeolite is produced at a Si / Al ratio of 25 and a phosphorus content of 6.0 wt%. Non-hydrotreated vacuum gas oil is cracked. Another difference is the use of bentonite clay in the matrix.

[0049] Example 13.

[0050] Similar to example 11, the difference is that the phosphorus-modified MFI type zeolite is carried out to a phosphorus content of 2.0 wt.%, zeolite Y contains 0.7 wt.% of rare earth oxides, with the following content of catalyst components in wt.%: phosphorus-modified MFI type zeolite 10; ultrastable zeolite Y 15; kaolin clay 22; amorphous aluminosilicate 28; aluminum oxide 25.

[0051] Example 14.

[0052] Similar to example 11, the difference is that zeolite Y contains 2.0 wt. % of rare earth oxides with the following content of catalyst components by weight: phosphorus-modified zeolite type MFI 10; ultrastable zeolite Y 15; kaolin clay 19; amorphous aluminosilicate 28; aluminum oxide 28.

[0053] Thus, as shown in the examples and Table 2, the use of the proposed catalyst increases the yield of light olefins at high feedstock conversion rates. Furthermore, the preparation of the proposed catalyst utilizes new reagents for depositing phosphorus on the zeolite.

[0054] Table 2

[0055]

Claims

Invention formula 1. A catalyst for increasing the yield of light olefins in a catalytic cracking process, comprising a phosphorus-modified MFI-type zeolite, an ultrastable Y zeolite and a matrix consisting of amorphous aluminosilicate, aluminum oxide and natural clay, characterized in that the MFI-type zeolite has a Si / Al ratio of 15 to 40, the ultrastable Y zeolite contains from 0.7 to 4.0 wt. % of rare earth oxides, with the following content of components in the catalyst, wt. %: phosphorus-modified MFI-type zeolite 7-20; ultrastable Y zeolite 10-17; natural clay 19-22; amorphous aluminosilicate 28-35; aluminum oxide 19-28.

2. The catalyst according to I.1, characterized in that the MFI type zeolite contains from 2.0 to 6.0 wt. % phosphorus.

3. The catalyst according to claim 1, characterized in that aluminum oxide from the product of thermochemical activation of alumina and kaolin clay are used as matrix components.

4. A method for preparing a catalyst for increasing the yield of light olefins in a catalytic cracking process, comprising mixing ultrastable zeolite Y and a phosphorus-modified MFI zeolite with components of a matrix consisting of amorphous aluminosilicate, aluminum oxide and natural clay, spray drying the resulting composition, followed by calcination, characterized in that the modification of the MFI zeolite is carried out by impregnation with phosphoric acid or urea phosphate, with a Si / Al ratio of from 15 to 40, the ultrastable zeolite Y is obtained by ion exchange for cations of rare earth elements and ammonium with a rare earth oxide content of from 0.7 to 4.0 wt. %, with the following content of components in the catalyst, wt. %: phosphorus-modified MFI zeolite 7-20; ultrastable zeolite Y 10-17; natural clay 19-22; amorphous aluminosilicate 28-35; aluminum oxide 19-28.

5. The method according to item 4, characterized in that impregnation with phosphoric acid or urea phosphate is carried out until the phosphorus content reaches 2.0 to 6.0 wt.% 6. The method according to paragraph 4, characterized in that aluminum oxide is obtained by processing the product of thermochemical activation of alumina.

7. The method according to item 4, characterized in that kaolin clay is used as natural clay.

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