RU2697711C1 - Method of preparing a catalyst and method for hydrocracking of vacuum gas oil using said catalyst - Google Patents

Abstract

FIELD: technological processes.SUBSTANCE: invention relates to a method of preparing a catalyst for hydrocracking, which produces high amounts of a product boiling in the range of middle distillates, and uses a catalyst which includes Beta zeolite as an active component of cracking. Described is a method of preparing a porous catalyst for hydrocracking a heavy vacuum gas oil based on Beta zeolite with a molar ratio SiO:AlO9–30:1, involving contact of Beta zeolite with acid, for conversion of zeolite to hydrogen form and partial dealumination, treatment with steam before acid extraction, application to hydrogenation component, such as nickel and tungsten, Beta zeolite is additionally treated with a solution of a chelating agent selected from: sulphosalicylic acid, ethylenediaminetetraacetic acid EDTA, sulpho-benzoic acid, and then superheated with steam at temperature higher than 550 °C for not less than 2 h. Hydrocracking of heavy vacuum gas oil having initial boiling point higher than 340 °C is carried out by contacting the feedstock with a catalyst prepared by the method described above at a temperature of from 230 to 500 °C. In presence of gaseous hydrogen at total pressure from 500 to 20,000 kPa, volume rate from 0.1 to 10 LHSV.EFFECT: increased output of middle distillates (diesel and oil fractions) with low pour point.2 cl, 8 tbl, 8 ex

Description

The invention relates to a method for preparing a catalyst for a hydrocracking process, which gives increased amounts of a product boiling in the range of middle distillates, and uses a catalyst comprising Beta zeolite as an active component of cracking.

Hydrocracking is the main conversion process used at many refineries around the world to reduce the molecular weight of crude oil and to convert heavy vacuum gas oil (VGO - hydrocarbons with a boiling point between 340 ° C and 565 ° C) into more valuable products, such as motor fuel , diesel and grease. Hydrocracking also leads to other useful results, such as the removal of sulfur and nitrogen from raw materials by hydrodesulfurization. The complete hydrocracking process design determines the conversion and selectivity achieved in the hydrocracking process; these two performance criteria are always related to the characteristics of the hydrocracking catalyst used in the process.

In recent years, the following trends have been observed in the global oil refining industry:

involvement in the processing of heavier oil fractions containing more heteroatomic impurities;

increasing the depth of oil refining in order to increase the yield of light petroleum products associated with an increase in the relative share of destructive processes;

toughening the environmental requirements for the quality of fuels, which makes them necessary for deep cleaning and refinement.

Using modern technology, the proportion of vacuum gas oil (VGO) in oil refining can reach 70%. The need to increase the depth of processing of heavy oil fractions into light motor fuels stimulated a wider introduction of hydrotreating and hydrocracking of vacuum gas oil, carried out under conditions of elevated temperatures and hydrogen pressures, differing in the used catalysts, process conditions and distribution of reaction products.

The effectiveness of the VGO hydrocracking process depends on the nature of the catalyst used, which, in turn, must have bifunctionality: on the one hand, be active in hydrogenation-dehydrogenation reactions, and on the other, in cracking reactions. Activity in hydrogenation-dehydrogenation reactions is provided by metals, and activity in cracking reactions is due to the presence of acidic sites of the support. Commonly used carriers are amorphous oxides such as aluminosilicates, crystalline zeolite in combination with alumina, or a mixture of crystalline zeolite and amorphous oxides (A. S. Ivanova, E. V. Korneeva, G. A. Bukhtiyarova, A. L. Nuzhdin, A. A. Budneva, I. P. Prosvirin, V. I. Zaikovsky, A. S. Noskov, Hydrocracking of Vacuum Gas Oil in the Presence of Supported Ni-W Catalysts, Kinetics and Catalysis, 2011. - V. 52, No. 3 )

The initial classification of hydrocracking catalysts is based on the nature of the cracking component prevailing in the catalyst. This classification divides hydrocracking catalysts into catalysts based on an amorphous aluminosilicate cracking component and based on zeolite cracking components such as Y zeolite. Hydrocracking catalysts typically include a zeolite component and a carrier such as alumina or silica-alumina, as well as a metal hydrogenation component.

Hydrocracking is a well-known process in which various zeolite catalysts are used. Although they may be effective in providing a yield of a distillate having one or more properties consistent with the intended use of the distillate, these catalysts generally suffer from a disadvantage - they do not provide a high yield of a product having good flow characteristics at low temperatures, especially low pour point and viscosity .

A known method of simultaneous hydrocracking and dewaxing of heavy oil using a catalyst comprising Beta zeolite plus a second zeolite, such as X or Y zeolite (US Pat. US No. 4757041A, 1988, C10G47 / 16). Refining methods are also known in which heavy oil is simultaneously hydrocracked and dewaxed using a catalyst based on Beta zeolite with a hydrogenation component (US Pat. US No. 5128024A, 1992, C10G11 / 05 and US Pat. No. 5284573).

The characteristics of Beta zeolite are described (US Pat. US No. 3308069, 1967, B01J29 / 7007). Zeolite Beta, which is used in the method disclosed in the description, has a molar ratio of SiO ₂ : Al ₂ O ₃ less than 9-30: 1.

It was found that a hydrocracking catalyst containing Beta zeolite with such characteristics has good selectivity and activity. Beta zeolite can be steamed. The catalyst contains a metal component of hydrogenation, such as nickel, cobalt, tungsten, molybdenum, or any combination thereof.

The hydrothermal treatment of zeolites for use in hydrocracking catalysts is widely known. However, steaming is a relatively crude procedure. For any given zeolite, steaming reduces the acidity of the zeolite. When using steam treated zeolite as a hydrocracking catalyst, the obvious result is that the total yield of distillate increases, but the activity of the catalyst decreases. This obvious trade-off between total distillate yield and activity needs to be taken into account, and this is the limit to the improvement achieved by steaming the zeolite.

Closest to the proposed invention is the implementation of the hydrocracking process disclosed in the description (US Pat. US No. 5284573), which includes contacting the feed stream containing hydrocarbons with a boiling point between 340 ° C and 565 ° C, with a catalyst containing a hydrogenation component and Beta zeolite .

The method includes contacting the zeolite with an acid, preferably a mineral acid, such as hydrochloric acid. Dealumination easily occurs at ambient temperature and moderately elevated temperatures and occurs with minimal loss of crystallinity with the formation of high-silicon forms of Beta zeolite. Zeolite is used in hydrogen form. The dealumination reaction proceeds easily at ambient temperatures, but slightly elevated temperatures, for example, up to 100 ° C, can be used.

After extraction treatment, the product is washed with water without impurities, preferably with distilled water, until the purified wash water has a pH in the approximate range of 5 to 8. If necessary, the zeolite can be steamed before acid extraction to increase the silica ratio: alumina and make zeolite more resistant to acid. Steam treatment can also help to increase the ease of acid removal and to maintain crystallinity during the extraction procedure.

The hydrogenation component includes a metal component such as nickel, cobalt, tungsten, molybdenum, or any combination thereof. The preferred composition of the hydrogenation metal component is nickel and tungsten with a weight amount of tungsten metal two to three times the amount of nickel. The amount of nickel or cobalt is preferably 2-8 wt.%. final catalyst. The amount of tungsten or molybdenum is preferably 8-22 wt.%. final catalyst. The total amount of the hydrogenation component is 10-30 wt.%.

The method of hydrocracking and dewaxing a heavy hydrocarbon vacuum gas oil having an initial boiling point above 340 ° C involves contacting the feed with a catalyst containing Beta zeolite as an acid component and a hydrogenation component at a temperature of from 230 to 500 ° C and in the presence of hydrogen gas with a total pressure from 500 to 20,000 kPa, a space velocity from 0.1 to 10 LHSV and a hydrogen circulation rate from 10 to 3500.

The main disadvantages of this method, taken as a prototype, is the insufficiently high yield of middle distillates (diesel and oil fractions) with a low pour point due to a significant decrease in the total acidity of Beta zeolite and at the same time a high fraction of the cracking process, as well as a low yield of isomerized paraffins.

The invention solves the problem of creating an improved process for the hydrocracking of vacuum gas oil with obtaining medium distillates (diesel and oil fractions) with a low pour point.

EFFECT: increased yield of middle distillates (diesel and oil fractions) with a low pour point during hydrocracking of vacuum gas oil due to a decrease in the fraction of cracking reactions, as well as an increase in the proportion of isomerization reactions.

The problem is solved by the proposed method for the preparation of the catalyst.

The acid component of the catalyst is Beta zeolite, pre-treated with solutions of organic or inorganic acids, granulated with alumina as a binder. An essential distinguishing feature of the proposed method from the prototype is that the acid component used to produce the porous catalyst is preliminarily treated with a solution of a chelating agent selected from the range: sulfosalicylic acid, EDTA (ethylenediaminetetraacetic acid), sulfobenzoic acid, and then with superheated water vapor temperature above 650 ° C for at least 2 hours

Pretreatment with a solution of a chelating agent selected from the series: sulfosalicylic acid, EDTA (ethylenediaminetetraacetic acid), sulfobenzoic acid, and then with superheated steam at a temperature above 650 ° C for at least 2 hours leads to:

firstly, to a decrease in the number of acid sites of the catalyst located mainly on the outer surface of the Beta zeolite crystals responsible for the cracking process, without affecting the acid sites in the volume of zeolite crystals (selective dealumination) and, as a result, to an increase in the yield of middle distillates (diesel and oil fractions) with a low pour point;

secondly, to remove the active centers of coke formation from the outer surface of the porous catalyst and, as a result, to increase the duration of the inter-regeneration run of the catalyst.

The problem is also solved by the proposed method of hydrocracking of heavy vacuum gas oil having an initial boiling point above 340 ° C, including contacting the feed with a catalyst containing Beta zeolite as an acid component and a hydrogenation component such as nickel and tungsten, using the catalyst prepared as described the above method at a temperature of from 230 to 500 ° C in the presence of hydrogen gas, at a total pressure of from 500 to 20,000 kPa, a space velocity of 0.1 to 10 LHSV and a circulation speed and hydrogen from 10 to 3500.

In the process of hydrocracking of vacuum gas oil in the presence of the specified catalyst, paraffins of normal structure are converted with the predominant formation of isomeric hydrocarbons, while the formation of light hydrocarbons due to cracking is reduced.

The invention is illustrated by the following examples and tables.

Example 1 (prototype)

For the preparation of a hydrocracking catalyst using zeolite Beta, which has a molar ratio SiO _2: Al ₂ O ₃ equal to 9. Said zeolite in the H form is subjected to dealumination 20% nitric acid solution under stirring at 80-85 ^{° C} for 2 h after. extraction treatment, the product is washed with distilled water until the purified wash water has a pH in the range from 5 to 8. The obtained zeolite is granulated with 30% alumina as a binder, calcined at a temperature of 550–600 ° С and applied hydrogenating component by incipient wetness impregnation of calculating the content of the catalyst and 17% W 4% Ni. The impregnating solution is prepared from ammonium metatungstate, nickel (II) hydroxide and citric acid. After impregnation, the granules produced drying for 12 hours at ¹²⁰ ° C and calcining for 4 hours at a temperature of 550 ° ^C before use in the hydrocracking catalyst sulfided pellets in a stream of gas phase H ₂ S for 2 hours at a temperature of 220 ° C, then for 4 hours at a temperature of 400 ° C.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ^about C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 1.

Table 1

Conversion C ₁₆ ,% 26.6 The gas output, wt. % 4.3 The output of C ₅ -C ₁₅ , wt. % 14.3 The output of iso-C ₁₆ , wt. % 8.0 The selectivity of the formation of C ₁ -C ₄ ,% 16,2 The selectivity of the formation of C ₅ -C ₁₅ ,% 53.7 Selectivity of iso-C ₁₆ formation,% 30.1 The molar ratio of ISO / N in C ₅ -C ₁₅ 3.2

Example 2 (prototype)

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 18. The specified zeolite in the H-form is subjected to dealumination with a solution of 20% nitric acid with stirring at a temperature of 80-85 ° C for 2 hours. After extraction treatment, the product is washed with distilled water until the purified wash water has a pH in the range from 5 to 8. The obtained zeolite is granulated with 30% alumina as a binder, calcined at a temperature of 550 - 600 ° C and applied hydrogenating component by incipient wetness impregnation of calculating the content of the catalyst and 17% W 4% Ni. The impregnating solution is prepared from ammonium metatungstate, nickel (II) hydroxide and citric acid. After impregnation, the granules produced drying for 12 hours at a temperature of 120 ° C and calcining for 4 hours at a temperature of 550 ^° C before use in the hydrocracking catalyst sulfided pellets in a stream of gas phase H ₂ S for 2 hours at a temperature of 220 ° C, then for 4 hours at a temperature of 400 ° C.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 2.

table 2

Conversion C ₁₆ ,% 22.5 The gas output, wt. % 3,7 The output of C ₅ -C ₁₅ , wt. % 11.6 The output of iso-C ₁₆ , wt. % 7.2 The selectivity of the formation of C ₁ -C ₄ ,% 16,4 The selectivity of the formation of C ₅ -C ₁₅ ,% 51.6 Selectivity of iso-C ₁₆ formation,% 32,0 The molar ratio of ISO / N in C ₅ -C ₁₅ 3.2

Example 3

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 9. The specified zeolite in the H-form is subjected to selective dealumination with a 10% sulfosalicylic acid solution with stirring at a temperature of 90-95 ° C for 2 hours. After extraction treatment, the product is washed with distilled water until the purified wash water has a pH in the range of 5 to 8. The resulting zeolite is granulated with 30% alumina as a binder. After granulation, the granules are dried for 12 hours at a temperature of 120 ° C and treated with superheated water vapor for 2 hours at a temperature of 550 ° C. The hydrogenating component is applied to the obtained granules by the method of impregnation by moisture capacity, based on the content of 17% W and 4% Ni in the catalyst. The impregnating solution is prepared from ammonium metatungstate, nickel (II) hydroxide and citric acid. After impregnation, the granules are dried for 12 hours at a temperature of 120 ° C and calcined at a temperature of 550 - 600 ° C. Before being used in the hydrocracking process, the catalyst granules are sulfidized gas-phase in a H ₂ S stream for 2 hours at a temperature of 220 ° C, then for 4 hours at a temperature of 400 ° C.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 3.

Table 3

Conversion C ₁₆ ,% 27.8 The gas output, wt. % 3,1 The output of C ₅ -C ₁₅ , wt. % 13.9 The output of iso-C ₁₆ , wt. % 10.8 The selectivity of the formation of C ₁ -C ₄ ,% 11.1 The selectivity of the formation of C ₅ -C ₁₅ ,% 50,0 Selectivity of iso-C ₁₆ formation,% 38.9 The molar ratio of ISO / N in C ₅ -C ₁₅ 4.0

Example 4

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 18. The indicated zeolite in the H-form is subjected to selective dealumination with a 10% sulfosalicylic acid solution with stirring at a temperature of 90-95 ° C for 2 hours. The remaining procedures for the preparation of the catalyst are similar to example 3.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 4.

Table 4

Conversion C ₁₆ ,% 26.8 The gas output, wt. % 3.0 The output of C ₅ -C ₁₅ , wt. % 13,2 The output of iso-C ₁₆ , wt. % 10.6 The selectivity of the formation of C ₁ -C ₄ ,% 11,2 The selectivity of the formation of C ₅ -C ₁₅ ,% 49.3 Selectivity of iso-C ₁₆ formation,% 39.5 The molar ratio of ISO / N in C ₅ -C ₁₅ 4.1

Example 5

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 9. The specified zeolite in the H-form is subjected to selective dealumination with a 10% solution of EDTA (ethylenediaminetetraacetic acid) with stirring and a temperature of 90-95 ° C for 2 hours. The remaining catalyst preparation procedures are similar to Example 3.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 5.

Table 5

Conversion C ₁₆ ,% 27.1 The gas output, wt. % 3.3 The output of C ₅ -C ₁₅ , wt. % 13.8 The output of iso-C ₁₆ , wt. % 10.0 The selectivity of the formation of C ₁ -C ₄ ,% 12,2 The selectivity of the formation of C ₅ -C ₁₅ ,% 50.9 Selectivity of iso-C ₁₆ formation,% 36.9 The molar ratio of ISO / N in C ₅ -C ₁₅ 4.1

Example 6

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 18. The indicated zeolite in the H-form is subjected to selective dealumination with a 10% solution of EDTA (ethylenediaminetetraacetic acid) with stirring and a temperature of 90-95 ° C for 2 hours. The remaining catalyst preparation procedures are similar to Example 3.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 6.

Table 6

Conversion C ₁₆ ,% 25.9 The gas output, wt. % 3,1 The output of C ₅ -C ₁₅ , wt. % 13,2 The output of iso-C ₁₆ , wt. % 9.6 The selectivity of the formation of C ₁ -C ₄ ,% 12.0 The selectivity of the formation of C ₅ -C ₁₅ ,% 51.0 Selectivity of iso-C ₁₆ formation,% 37.0 The molar ratio of ISO / N in C ₅ -C ₁₅ 4.0

Example 7

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 9. The indicated zeolite in the H-form is subjected to selective dealumination with a 10% solution of sulfobenzoic acid with stirring at a temperature of 90-95 ° C for 2 hours. The remaining procedures for the preparation of the catalyst are similar to example 3.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 7.

Table 7

Conversion C ₁₆ ,% 26.8 The gas output, wt. % 3.4 The output of C ₅ -C ₁₅ , wt. % 14.0 The output of iso-C ₁₆ , wt. % 9,4 The selectivity of the formation of C ₁ -C ₄ ,% 12.7 The selectivity of the formation of C ₅ -C ₁₅ ,% 52,2 Selectivity of iso-C ₁₆ formation,% 35.1 The molar ratio of ISO / N in C ₅ -C ₁₅ 4.0

Example 8

To prepare the hydrocracking catalyst, Beta zeolite is used, which has a molar ratio of SiO ₂ : Al ₂ O ₃ equal to 18. The specified zeolite in the H-form is subjected to selective dealumination with a 10% solution of sulfobenzoic acid with stirring at a temperature of 90-95 ° C for 2 hours. The remaining procedures for the preparation of the catalyst are similar to example 3.

The catalyst load in the reactor is 2 g (0.25-0.5 mm fraction), the catalyst is mixed with silicon carbide up to 4 ml. Hexadecane with the addition of dimethyl disulfide (equivalent to 200 ppm sulfur) is used as raw material. The hydrocracking process is carried out at a temperature of 300 ° C, a pressure of 40 bar, a mass feed rate of 4 h ^-1 and a hydrogen / feed ratio of 300 m ³ / m ³ .

The results are shown in table 8.

Table 8

Conversion C ₁₆ ,% 26.0 The gas output, wt. % 3,1 The output of C ₅ -C ₁₅ , wt. % 13.6 The output of iso-C ₁₆ , wt. % 9.3 The selectivity of the formation of C ₁ -C ₄ ,% 11.9 The selectivity of the formation of C ₅ -C ₁₅ ,% 52.3 Selectivity of iso-C ₁₆ formation,% 35.8 The molar ratio of ISO / N in C ₅ -C ₁₅ 4.0

Claims (2)

1. A method of preparing a porous heavy vacuum gas oil hydrocracking catalyst based on Beta zeolite with a molar ratio of SiO ₂ : Al ₂ O _{3 of} 9-30: 1, comprising contacting Beta zeolite with acid to convert the zeolite to a hydrogen form and partially dealumination, steam treatment before acid extraction, applying a hydrogenation component, such as nickel and tungsten, characterized in that the Beta zeolite is further subjected to treatment with a solution of a chelating agent selected from the range: sulfosalicylic acid, ethylene iamintetrauksusnaya acid EDTA, sulfobenzoic acid, and then with superheated steam at a temperature above 550 ° C for at least 2 hours. 2. A method of hydrocracking a heavy vacuum gas oil having an initial boiling point above 340 ° C, comprising contacting the feed with a catalyst containing Beta zeolite as an acid component and a hydrogenation component such as nickel and tungsten, characterized in that the catalyst is used as a catalyst, prepared according to claim 1, the method is carried out at a temperature of from 230 to 500 ° C in the presence of hydrogen gas at a total pressure of from 500 to 20,000 kPa, a space velocity of from 0.1 to 10 LHSV.