RU2767413C1 - Method for obtaining a catalyst for hydrofinishing of hydrocarbon raw materials - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to the field of catalysis and oil refining, in particular to a method for preparing a hydrofinishing catalyst. A carrier containing aluminosilicate and aluminum oxide is prepared by mixing the initial components: aluminosilicate containing from 5 to 70 wt. % of silicon oxide, and boehmite, by peptization, molding, drying and calcination with temperature rise up to 500-600°C. Platinum and palladium or platinum from an impregnating solution containing Pt(NH₃)₄(NO₃)₂ and Pd(NH₃)₄(NO₃)₂ or Pt(NH₃)₄(NO₃)₂ and an ammonia solution with a molar ratio of ammonia: platinum + palladium or platinum from 1 to 5 are applied to the carrier, 0.1-1.0 wt. %. The resulting mixture is heated to a temperature of 60-95°C. The impregnated catalyst is dried and calcined at a temperature of 350-450°C at a rate of temperature rise up to 40°C/h.

EFFECT: increase in the activity and stability of the hydrofinishing catalyst of hydrocarbon raw materials.

3 cl, 4 tbl, 22 ex

Description

The invention relates to the field of catalysis and oil refining, in particular to a method for preparing a hydrofinishing catalyst aimed at improving the color and/or oxidative stability of base oils by hydrogenating unsaturated hydrocarbons of the feedstock.

The hydrofinishing process is used to improve the quality of products of hydrocatalytic processes, during which the hydrogenation of unsaturated compounds of the feedstock does not go deep enough, or in which the formation of unsaturated compounds by dehydrogenation of the original hydrocarbons is possible. Such processes, in particular, include the processes of hydrotreatment and hydroconversion, isodeparaffinization of diesel and oil fractions (hydrocracking residues, hydroconversion products of raffinates, etc.) and highly paraffinic raw materials (slacks, petrolatums, etc.). Thus, in the description and examples of the present invention, the term "hydrofinishing" denotes a process in which the target reactions are the hydrogenation of unsaturated (mainly aromatic) hydrocarbons in the products of hydrocatalytic processes.

It is known from the literature that metals such as platinum and palladium exhibit high activity in hydrogenation reactions. At the same time, they are inactive in side reactions of hydrogenolysis, leading to a loss in the yield of target processes, which compares favorably with other platinum group metals (PGMs), which are highly active both in hydrogenation reactions and in hydrogenolysis reactions. Piegsa A., Korth W., Demir F., Jess A. Hydrogenation and Ring Opening of Aromatic and Naphthenic Hydrocarbons Over Noble Metal (Ir, Pt, Rh)/Al ₂ O ₃ Catalysts. Catalysis letters. 2012,v. 142, p. 531-540.

The activity and stability of the hydrofinishing catalyst is affected by the degree of dispersion (size) of metal particles on the carrier surface. The use of bimetallic catalysts, for example, a combination of platinum and palladium in various ratios, can increase the activity and stability of the catalyst by increasing the dispersion (reducing the size) of metal particles Stanley JNG, Heinroth F., Weber CC, Masters AF, Maschmeyer T. Robust bimetallic Pt- Ru catalysts for the rapid hydrogenation of toluene and tetralin at ambient temperature and pressure. Applied Catalysis A: General. 2013,v. 454.p. 46-52, Suppino RS, Landers R., Cobo AJG Influence of noble metals (Pd, Pt) on the performance of Ru/Al ₂ O ₃ based catalysts for toluene hydrogenation in liquid phase. Applied Catalysis A: General. 2016, v. 525, p.41-49. Ali AG, Ali LI, Aboul-Fotouh SM, Aboul-Gheit AK Hydrogenation of aromatics on modified platinum-alumina catalysts. Applied Catalysis A: General. 1998, v. 170, p. 285-296.

Many literature sources point out the prospects of using platinum-palladium hydrogenation catalysts, which are characterized by increased activity and stability compared to monometallic catalysts. Coq B., Figueras F. Bimetallic palladium catalysts: influence of the co-metal on the catalyst performance. Journal of Molecular Catalysis A: Chemical. 2001, v. 173, p. 117-134.

When bimetallic catalysts are used, the catalyst performance in hydrogenation reactions is significantly affected by the method of depositing metals on the catalyst surface: simultaneously or sequentially.

Thus, Fujikawa T., Idei K., Ebihara T., Mizuguchi H., Usui K. Aromatic hydrogenation of distillates over SiO ₂ -Al ₂ O ₃ -supported noble metal catalysts. Applied Catalysis A: General. 2000, v. 192, p. 253-261 indicate that the preparation of the catalyst by applying active metals in one stage leads to greater activity in the process of hydrogenation of aromatic hydrocarbons in the composition of middle distillates.

The degree of dispersion of metal particles and, consequently, the activity of the hydrofinishing catalyst is affected not only by the amount of metals, but also by the properties of the carrier surface, in particular, by acidity. Literature data indicate that an excessive increase in the acidity of the support leads to a sharp increase in the proportion of hydrocracking side processes, which reduces the yield of target products. At the same time, the moderate acidity of the support, as a rule, improves the performance of the hydrogenation catalyst:

- the effect of "chemical anchor" - acid centers contribute to high dispersion and prevent the aggregation of metal particles due to the binding of PGM and acid center (AC);

- the metal acquires an electron-deficient character;

- the metal functions as part of a single bifunctional active center: Me ⁰ -CC.

Various literature sources present various methods for moderately increasing the acidity of hydrogenation (hydrofinishing) catalysts, which increases the fineness of metal particles, but does not lead to acceleration of hydrocracking reactions. Ali AG, Ali LI, Aboul-Fotouh SM, Aboul-Gheit AK Hydrogenation of aromatics on modified platinum-alumina catalysts. Applied Catalysis A: General. 1998, v. 170, p.285-296. Kishore Kumar SA, John M., Pai SM, Niwate Y., Newalkar BL Low temperature hydrogenation of aromatics over Pt-Pd/SiO ₂ -Al ₂ O ₃ catalyst. fuel processing technology. 2014,v. 128, p. 303-309, in particular:

- introduction of halogens (chlorine or fluorine) into the composition of the carrier (aluminum oxide);

- the use of aluminosilicates of various compositions containing Bronsted acid centers as carriers or their components;

- the use of heteropolyacids in the manufacture of a catalyst.

There is a significant number of literary sources in which metal components are deposited on zeolites of various structures. It should be especially noted that most zeolites are characterized by high acidity, which can not only increase the activity of the hydrofinishing catalyst, but also accelerate hydrocracking reactions, thereby reducing the selectivity of the process. Ne T., Wang Y., Miao P., Li J., Wua J., Fang Y. Hydrogenation of naphthalene over noble metal supported on mesoporous zeolite in the absence and presence of sulfur. fuel. 2013, v.106, p.365-371.

Known hydrofinishing catalyst, which is a platinum-palladium sample. The carrier is prepared by mixing Pural SB alumina, Siral 40 aluminosilicate, and F4M methylcellulose ether, which is then impregnated once with solutions of platinum and palladium salts at concentrations of, for example, 0.2 wt.% and 0.16 wt.%, respectively. In individual samples, the ratio of platinum and palladium in the catalyst varied from 2.5:1 to 1:2. The calcination temperature of the catalyst was 450°C. The hydrofinishing process was carried out at a temperature of 230°C and a feed space velocity of 1.0 h ^-1 , a pressure not exceeding 7.6 MPa. As a result, the aromatic content in the stable oil was reduced to 5.8 wt.% with a viscosity index of 103. US 5993644 A, publ. 11/30/1999.

Closest to the proposed invention is the hydrofinishing catalyst described in Kishore Kumar SA, John M., Pai SM, Niwate Y., Newalkar BL Low temperature hydrogenation of aromatics over Pt-Pd/SiO ₂ -Al ₂ O ₃ catalyst. fuel processing technology. 2014,v. 128, p. 303-309 containing platinum and palladium on an aluminosilicate carrier. In this paper, the influence of the acidity of the support and the metal content of a bimetallic platinum-palladium hydrofinishing catalyst on its activity is considered. As part of hydrofinishing catalyst carriers, a series of commercial aluminosilicates Siral (manufactured by Sasol) with a silicon oxide content of 1.5 to 70 wt.% was investigated. The catalyst carrier was prepared by mixing Siral with a binder - alumina, the source of which was Pural SB boehmite (Sasol), which were pre-dried at a temperature of 120°C for 10-20 hours. Acetic acid was used as a peptizer in an amount of 5 wt.% The molding of the resulting paste was carried out using an extruder with a die diameter of 1.6 mm. Extrudates 3 mm long were dried at a temperature of 130°C for 10–20 h, then calcined at a temperature of 550°C for 7 h. Platinum and palladium were deposited by impregnation by moisture capacity using an impregnation solution containing tetraammineplatinum nitrate (Pt(NH ₃ ) ₄ (NO ₃ ) ₂ ) and tetraammine palladium nitrate Pd(NH ₃ ) ₄ (NO ₃ ) ₂ . During the impregnation step, the pH was maintained at about 9. The content of platinum and palladium in the catalyst samples varied in the range of 0.125-0.25 wt.% for each of the metals at a mass ratio of 1:1. The resulting catalysts were dried for 14–18 h at 130°C and calcined at 400°C for 4 h.

The catalysts were tested on a laboratory setup using model feedstock (50 wt.% toluene in dodecane and 5 wt.% naphthalene in dodecane). Before testing, the catalyst was dried for 10–20 h at a temperature of 150°С, followed by reduction in a hydrogen flow at a temperature of 300°С for 5 h. After reduction, the reactor was cooled to the required temperature, and the required hydrogen pressure was built up. When studying the hydrogenation activity of catalysts in the toluene hydrogenation reaction, the process was carried out in a reactor with a fixed catalyst bed at a pressure of 2 MPa, a temperature of 110–150°C, and a feed space velocity of 1–5 h ^-1 . When studying the hydrogenation activity of the catalysts in the naphthalene hydrogenation reaction, the process was carried out in a reactor with a fixed catalyst bed at a pressure of 2 MPa, a temperature of 130–250°C, and a feed space velocity of 1–12 h ^-1 . In the course of the study, it was found that in the reactions of hydrogenation of aromatic hydrocarbons, the catalyst exhibits the highest activity, including a carrier from a mixture of aluminosilicate with a content of 40 wt.% silicon oxide (Siral 40) and aluminum oxide, with platinum deposited on them in an amount of 0.18 wt. % and palladium - in the amount of 0.18 wt.%.

The disadvantages of the catalyst preparation method include the lack of a description of the catalyst preparation conditions, which have a significant impact on the catalyst performance in the hydrofinishing process:

- the rate of temperature rise during the calcination of the catalyst (after the application of Pt and Pd);

- temperature of deposition of Pt and Pd on the carrier.

In addition, the tests of the catalyst described in this article were carried out on model feedstock, which makes it difficult to evaluate its effectiveness for real hydrofinishing feedstock. It should also be noted that the loading of the catalyst in this study was carried out by weight, while in real conditions the loading of the catalyst is carried out by volume of the catalyst. In this regard, the data on the activity of the catalyst does not reflect the changes associated with the difference in bulk density of the tested catalysts.

The technical problem of the invention is to develop a method for preparing a base oil hydrofinishing catalyst to improve color and/or oxidative stability by hydrogenating unsaturated hydrocarbons of the feedstock.

The technical result consists in increasing the activity and stability of the catalyst for hydrofinishing of hydrocarbon raw materials.

The technical result is achieved by the fact that a method for producing a hydrofinishing catalyst for hydrocarbon raw materials, including preparing a carrier containing aluminosilicate and aluminum oxide, mixing the starting components, peptization, molding, drying and calcining, applying platinum and palladium or platinum to the carrier from an impregnating solution containing tetraammineplatinum nitrates and tetraamminepalladium or tetraammineplatinum, drying and calcining the impregnated catalyst, according to the invention, 0.1-1.0 wt.% of platinum and palladium or platinum is applied to the carrier from the impregnating solution additionally containing an ammonia solution at a molar ratio of ammonia: platinum and palladium or platinum from 1 to 5, the resulting mixture is heated to a temperature of 60-95°C, the impregnated catalyst is dried and calcined at a temperature of 350-450°C with a temperature rise rate of up to 40°C/h.

The achievement of the technical result is also facilitated by the fact that aluminum oxide has a specific surface area of 170-450 m ² /g, and the aluminosilicate contains from 5 to 70 wt.% silicon oxide. The catalyst additionally contains ruthenium in an amount of up to 0.1 wt.%.

Н.,

F., Weitkamp J. Handbook of Heterogeneous Catalysis, v.82nd Edition. WILEY-VCH, 2008, p. 4270.An important aspect of the invention are the conditions for applying platinum group metals to the carrier of the hydrofinishing catalyst for hydrocarbon feedstock. The active center of hydrofinishing catalysts containing aluminosilicates is a structure (adduct) of the Me ⁰ -CC type, consisting of reduced PGM and Brönsted or Lewis acid sites, Lewis acid sites. Ertl G.,

N.,

F., Weitkamp J. Handbook of Heterogeneous Catalysis, v.82nd Edition. WILEY-VCH, 2008, p. 4270.

Thus, reducing the distance between the CC and the metal particle makes it possible to increase the efficiency of the catalyst. Based on this, when applying platinum and palladium to a hydrofinishing catalyst carrier, it is desirable to choose process conditions that facilitate the deposition of PGM on the acid component (aluminosilicate) and hinder its deposition on the binder material (alumina). To determine such conditions, we studied the influence of temperature and the content of a competitor during the deposition of Pt and Pd from ammonia complexes on the efficiency of their deposition on the surface of aluminum oxide and aluminosilicate. Pural SB was used as alumina, and Siral 40 HPV was used as aluminosilicate, pre-calcined under the following conditions: rise to a temperature of 550°C at a rate of 50°C/h, holding at this temperature for -4 h.

Platinum and palladium were deposited together. To do this, 1 g of the powder was placed in 9 ml of a solution containing the required amount of Pt(NH ₃ ) ₄ (NO ₃ ) ₂ and Pd(NH ₃ ) ₄ (NO ₃ ) ₂ , as well as NH ₄ OH at the rate of 1, 5 and 10 mol per 1 mol of Pt + Pd. The initial content of platinum and palladium in the solutions was the same and was determined as 0.375 wt.% Pt and 0.75 wt.% Pd calculated on the “dry” weight of Siral 40 HPV, taking into account the TFR (which corresponds to 0.15 wt.% Pt and 0 ,30 wt.% Pd on a catalyst containing 40 wt.% of this aluminosilicate). The deposition of a mixture of Pt and Pd was carried out with stirring at room temperature or at a temperature of 95°C for 120 min. A reflux condenser was used to prevent evaporation of the solution when the process was carried out at a temperature of 95°C. After the end of the process, the solution was centrifuged and the content of platinum and palladium in it was determined. Data on the degree of deposition of platinum and palladium from solutions on calcined samples of Siral 40 HPV and Pural SB depending on the temperature and the amount of the competitor are presented in Table 1.

The data obtained indicate that an increase in temperature from room temperature to 95°C promotes the deposition of Pt and Pd on Siral 40 HPV, but makes it difficult to apply it to the binder. Reduced ammonia content in the solution (1-5 mol NH ₄ OH per 1 mol Pt + Pd) leads to a decrease in the deposition of Pt and Pd on alumina, but to a lesser extent affects the degree of deposition of these metals on Siral 40 HPV.

Thus, to increase the proportion of Pt and Pd deposited on the acid component of the catalyst and, accordingly, to increase its efficiency in the hydrofinishing process, it is desirable to use:

- increased temperature of application of Pt and Pd or platinum - 60-95°C (using a temperature of more than 95°C is impractical, as it can lead to uncontrolled boiling of the solution during the process);

- ratio from 1 to 5 mol NH ₄ OH per 1 mol Pt + Pd or platinum.

The invention is illustrated but not limited by the following examples.

Example 1

The preparation of catalyst 1 is carried out in two stages. At the first stage, a shaped catalyst carrier is prepared using commercial aluminosilicate Siral 40 HPV (containing 40 wt.% silicon oxide) as an acid component, and Pural SB brand boehmite as a binder precursor, which, upon calcination, turns into alumina, having a specific area surface, measured by the BET method - 250 m ² /g. At the second stage, active metals are deposited.

Stage 1 includes the following stages:

1.1 Mixing 40 g (dry basis) of aluminosilicate powder with 60 g (expressed as alumina) of boehmite.

1.2 Adding to the resulting mixture in small portions a solution consisting of 150-200 ml of distilled water, 2.3-3.1 ml of a peptizer - 65 wt.% nitric acid and 4.0-5.3 ml of a plasticizer - triethylene glycol. The resulting mass was stirred until a homogeneous paste.

1.3 Paste molding using a laboratory piston extruder (die diameter 1.6 mm). The extrudates were dried at room temperature for 14–18 h, then dried at a stepwise increase in temperature (60, 80, 120°C) with holding for 2, 4, and 4 h at each temperature, then crushed to granules 5–7 mm long.

1.4 Calcination of carrier granules for 4 hours at a temperature of 550°C while raising the temperature at a rate of 50°C/hour.

Stage 2 includes the following stages:

2.1 Addition to 100 g of carrier cooled to room temperature (95 g of "dry" carrier, taking into account losses on ignition) 230-480 ml of an impregnating solution (pH = 10.5-11.5) containing (Pt (NH ₃ ) ₄ (NO ₃ ) ₂ (based on 0.15 wt.% platinum metal in the final catalyst), Pd(NH ₃ ) ₄ (NO ₃ ) ₂ (based on 0.3 wt.% palladium metal in the final catalyst ) and 25 wt.% aqueous ammonia solution (based on 5 mol of NH ₄ OH per 1 mol of the sum of platinum group metals) dissolved in distilled water.

2.2 Heating the mixture to a temperature of 95°C, keeping it at this temperature for -6 hours. A reflux condenser was used to prevent evaporation of the solution.

2.3 Holding the carrier in a solution of platinum and palladium for 16 hours at room temperature.

2.4 Separation of granules from the impregnating solution. Washing the catalyst granules with distilled water.

2.5 Drying of the catalyst granules at a stepwise increase in temperature (60, 80, 120°C) with a holding time of 2, 4 and 4 hours at each temperature.

2.6 Ignition of the dried catalyst for 3 hours at a temperature of 400°C while raising the temperature at a rate of 20°C/h.

The resulting catalyst contained 0.15 wt.% Pt and 0.3 wt.% Pd supported on a carrier containing 40 wt.% Siral 40 HPV and 60 wt.% alumina.

Example 2

Catalyst 2 was synthesized similarly to catalyst 1, except that Pural TH 80 boehmite was used as a binder precursor, which, upon calcination, transforms into alumina, which has a BET specific surface area of 195 ^m2 /g.

Example 3

Catalyst 3 was synthesized similarly to catalyst 1, except that the binder precursor was Disperal HP 14 boehmite, which on calcination transforms into alumina, which has a BET specific surface area of 170 ^m2 /g.

Example 4

Catalyst 4 was synthesized similarly to Catalyst 1, except that:

- the media instead of Siral 40 HPV contained a commercial aluminosilicate Siral 5 (containing 5 wt.% silicon oxide);

- according to paragraph 2.1, 0.3 wt.% Pt was applied to the carrier.

Example 5

Catalyst 5 was synthesized similarly to Catalyst 1, except that the carrier instead of Siral 40 HPV contained commercial aluminosilicate Siral 70 HPV (containing 70 wt.% silica). The application temperature of Pt and Pd is 60°C and the exposure of the mixture for 7 hours, at room temperature - 20 hours.

Example 6

Catalyst 6 was synthesized similarly to Catalyst 1, except that:

- the content of Siral-40 HPV in the composition of the media was 10 wt.%;

- according to paragraph 2.1, 0.3 wt.% Pt was applied to the carrier.

Example 7

Catalyst 7 was synthesized similarly to Catalyst 1, except that:

- the content of Siral-40 HPV in the composition of the media was 80 wt.%;

- as a binder precursor, boehmite was used, which, when calcined, turns into aluminum oxide, having a specific surface area measured by the BET method - 450 m ² /g;

- according to paragraph 2.1, 0.3 wt.% Pt was applied to the carrier.

Example 8

Catalyst 8 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.1 wt.% Pt was deposited on the carrier.

Example 9

Catalyst 9 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.3 wt.% Pt was deposited on the support.

Example 10

Catalyst 10 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.225 wt.% Pt and 0.225 wt.% Pd were deposited on the support.

Example 11

Catalyst 11 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.3 wt.% Pt and 0.15 wt.% Pd were deposited on the support.

Example 12

Catalyst 12 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.3 wt.% Pt, 0.05 wt.% Pd and 0.1 wt.% ruthenium, the source of which was Ru(NH ₃ ) _{6Cl2 .}

Example 13

Catalyst 13 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.5 wt.% Pt and 0.5 wt.% Pd were deposited on the support.

Example 14

Catalyst 14 was synthesized similarly to catalyst 1, except that the deposition of Pt and Pd was carried out sequentially. First, the steps in paragraphs 2.1-2.6 were performed with the application of 0.3 wt.% palladium (calculated on the finished catalyst). Then the actions according to paragraphs 2.1-2.6 were carried out with the application of 0.15 wt.% platinum (calculated on the finished catalyst).

Example 15

Catalyst 15 was synthesized similarly to catalyst 1, except that the deposition of Pt and Pd was carried out sequentially. First, the steps in paragraphs 2.1-2.6 were performed with the application of 0.15 wt.% platinum (calculated on the finished catalyst). Then the actions according to paragraphs 2.1-2.6 were performed with the application of 0.3 wt.% palladium (calculated on the finished catalyst).

Example 16

Catalyst 16 was synthesized similarly to catalyst 1, except that, according to paragraph 1.4, the calcination of carrier granules was carried out for 4 h at a temperature of 450°C with a rise rate of 50°C/h.

Example 17

Catalyst 17 was synthesized similarly to catalyst 1, except that, according to paragraph 1.4, the support granules were calcined for 4 h at a temperature of 650°С with a rise rate of 50°С/h.

Example 18

Catalyst 18 was synthesized similarly to catalyst 1, except that, according to paragraph 2.6, the dried catalyst was calcined for 3 h at a temperature of 300°С with a rise rate of 20°С/h.

Example 19

Catalyst 19 was synthesized similarly to catalyst 1, except that, according to paragraph 2.6, the dried catalyst was calcined for 3 h at a temperature of 500°С with a rise rate of 20°С/h.

Example 20

Catalyst 20 was synthesized similarly to catalyst 1, except that, according to paragraph 2.6, the dried catalyst was calcined for 3 h at a temperature of 400°С with a rise rate of 40°С/h.

Example 21

Catalyst 21 was synthesized similarly to catalyst 1, except that, according to paragraph 2.1, 0.3 wt.% Pd was deposited on the carrier

Example 22

Catalyst 22 was synthesized similarly to Catalyst 1, except that:

- the carrier of the catalyst contained 100 wt.% alumina, the source of which was Pural SB brand boehmite;

- according to paragraph 2.1, 0.3 wt.% Pt was applied to the carrier.

Testing samples in the process of hydrofinishing.

The samples prepared according to examples 1-22 were tested in the process of hydrofinishing using the product of isodeparaffinization of the hydrocracking residue as a raw material. Physical and chemical properties of raw materials are presented in table 2.

The process of hydrofinishing was carried out on a flow laboratory installation. The experiments were carried out as follows.

The catalyst was loaded into the center of the reactor; quartz particles and ceramic balls were placed above and below the catalyst bed. At the first stage, at atmospheric pressure, the catalyst was dried in a stream of nitrogen at a temperature of 150°C for 2 h. Then, the catalyst was reduced in a stream of hydrogen at a stepwise increase in temperature to 250 and 400°C, holding at each stage for 1 and 3 h, respectively. Drying and reduction of the catalyst was carried out once for each catalyst.

After drying and reduction, the reactor was cooled to the first operating temperature, the required hydrogen pressure was increased, and the required hydrogen flow rate was set. After reaching the operating temperature, the supply of raw materials was switched on at a given volumetric velocity. Before taking each target sample, an intermediate unanalyzed sample was accumulated.

The parameters of the hydrofinishing process are presented in Table 3.

As the main indicators of the hydrofinishing process, the following were used: the average degree of hydrogenation (SHG), the loss of catalyst activity (PAA) and the specific activity of the catalyst (SAC).

To assess the activity of the catalyst, the degree of hydrogenation (SH, %) was calculated using the following formula:

CH _pr - the content of saturated hydrocarbons in the process product, wt.%

CH _c is the content of saturated hydrocarbons in the raw material of the process, wt.%

The SG was the arithmetic mean of the SG values for all points obtained at operating temperature.

To assess the stability of the catalyst, the catalyst activity loss index (PAA, %/h) was calculated using the following formula:

t ₁ - the value of the duration of the experiment at the time of selection of the first target sample, h;

t ₂ - the value of the duration of the experiment at the time of selection of the last target sample, h;

CG _t1 - the degree of hydrogenation at the point t ₁ ;

SG _t2 - the degree of hydrogenation at the point t ₂ .

We also calculated the specific activity of the catalyst - UAC according to the following formula:

X _arom - the initial content of aromatic hydrocarbons in the raw material, wt.%;

G _raw - feedstock consumption, g/h;

M _arom.feed - average molecular weight of aromatic hydrocarbons of the feedstock, g/mol;

X _arom.res. - residual content of aromatic hydrocarbons, wt.%;

M _arom.prod. - average molecular weight of aromatic hydrocarbons of the product, g/mol.

m _cat is the weight of the loaded catalyst, g;

X _Pt - mass fraction of platinum in the catalyst, wt.%;

A _Pt - atomic mass of platinum, g/mol;

X _Pd - mass fraction of palladium in the catalyst, wt.%;

A _Pd - atomic mass of palladium, g/mol;

X _ru - mass fraction of ruthenium in the catalyst, wt.%;

A _ru is the atomic mass of ruthenium, g/mol.

The tested catalysts in the process of hydrofinishing provided the yield of hydrogenated products in the range of 99-102 wt.%, that is, no significant side reactions of hydrocracking or hydrogenolysis were observed. At the same time, an increase in the process temperature to 230°C also did not cause a decrease in the yield below the specified range. The products of the hydrofinishing process differed little from the raw materials in terms of viscosity at 100°C (4.3-4.4 cSt with a value for raw materials of 4.34 cSt), VI (113-116 with a value for raw materials of 113) and fractional composition.

Data on the main performance indicators and the composition of hydrofinishing catalysts are presented in Table 4.

The presented data indicate that the improvement in activity (according to SSG and/or AAA) and/or stability of the catalyst was achieved with:

- introduction of aluminosilicate into the composition of the catalyst; for example - see results for catalysts 9 and 22;

- use in the composition of the catalyst binder aluminum oxide with a high specific surface area (not less than 170 m ² /g); see results for catalysts 1, 2, 3 and 7;

- calcination of the carrier at a temperature of 550°C (±50°C); see results for catalysts 1, 16 and 17;

- the use of platinum or a mixture of platinum and palladium as a metal component of the catalyst: the introduction of palladium leads to a decrease in the VAC, but an improvement in the stability of the catalyst; for example - see results for catalysts 1, 9 and 21;

- introduction of small amounts of Ru into the composition of the catalyst (up to 0.1 wt.%); see results for catalysts 11 and 12;

- deposition of platinum group metals within one stage at a molar ratio of ammonia and Pt + Pd in an impregnating solution from 1 to 5; see results for catalysts 1, 14 and 15;

- application temperature of Pt or Pt + Pd - 60-95°C;

- calcining the catalyst at a temperature of 400°C (±50°C) with the rate of its temperature rise to 40°C/h; see results for catalyst 1, 18, 19 and 20.

For samples based on Siral 40 HPV, the SSG and the stability of the catalyst increase as the content of aluminosilicate decreases from 80 to 10 wt.%. At the same time, the AAC data indicate that the rate of hydrogenation of aromatic hydrocarbons in terms of the amount of platinum group metals (PGM) in the catalyst composition increased as the content of the acid component increased. Thus, per mole of PGM, the more acidic catalysts worked more actively. Such a difference between the work of the catalyst bed (average degree of hydrogenation) and the AAC is explained by the fact that during testing (and during operation) the catalyst is loaded in a fixed volume. At the same time, the application of the precious metal is based on the weight of the catalyst. In this regard, with significant differences in the bulk density of the catalysts, the same catalyst layer contains a different amount of PGM. Thus, the efficiency of the catalyst per catalyst bed (CCB) and per PGM unit (UAC) can differ significantly, which was observed in the case under study. The reason for this for catalysts differing in Siral material content is the fact that the samples containing more aluminosilicate had a much lower bulk density due to the fact that they had a higher porosity. Thus, more active catalysts containing large amounts of an acidic component, which contributes to PGM dispersity and a decrease in its electron density, at a fixed volume load, showed lower values of the average degree of hydrogenation due to a lower bulk density. For catalysts for hydrofinishing of hydrocarbon feedstocks, it is desirable to maximize both SSG and AAA.

Thus, the claimed combination of distinctive features of the invention makes it possible to increase the activity of the catalyst and significantly improve the stability of the catalyst for the hydrofinishing of hydrocarbon feedstock.

Claims (3)

1. A method for producing a hydrofinishing catalyst for hydrocarbon raw materials, characterized in that a carrier containing aluminosilicate and aluminum oxide is prepared by mixing the initial components: aluminosilicate containing from 5 to 70 wt.% silicon oxide, and boehmite, peptization, molding, drying and calcination with by raising the temperature to 500-600 ° C, 0.1-1.0 wt.% of platinum and palladium or platinum is applied to the carrier from an impregnating solution containing tetraammineplatinum and tetraamminepalladium or tetraamineplatinum nitrates and an ammonia solution at a molar ratio of ammonia: platinum + palladium or platinum from 1 to 5, the resulting mixture is heated to a temperature of 60-95°C, the impregnated catalyst is dried and calcined at a temperature of 350-450°C with a temperature rise rate of up to 40°C/h. 2. The method according to p. 1, characterized in that the aluminum oxide has a specific surface area of 170-450 m ² /g. 3. The method according to p. 1, characterized in that the catalyst additionally contains ruthenium in an amount of up to 0.1 wt.%.