RU2623432C1 - Method of preparation of carrier for catalyst of hydraulic cleaning of oil faces - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method for preparing a carrier for hydrotreating catalysts based on active alumina is provided, comprising mixing aluminium hydroxide "crude cake" with aluminium hydroxide powder, treating the mixture with an organic acid solution, forming, drying and calcining. Aluminium hydroxide, a "crude cake", is produced by a single-stream precipitation method, which involves the precipitation of aluminium hydroxide from the sodium aluminate solution with nitric acid, and the components are mixed in a ratio (wt %) 1:1-2.3.

EFFECT: decrease in bulk density, increase water absorption, increase mechanical strength, increase the specific surface area, simplify the technology of preparation, reduce material and energy costs and reduce production costs.

3 cl, 5 tbl

Description

The invention relates to a method for preparing a carrier based on active alumina for hydrotreating catalysts.

It is known that alumina with a certain size, shape of granules and various texture characteristics is used as a carrier. The alumina precursor, aluminum hydroxide, is prepared by the precipitation of solutions of aluminum salts {Al (NO ₃ ) ₃ , AlCl ₃ , Al ₂ (SO ₄ ) ₃ , NaAlO ₂ } with aqueous solutions of the precipitant (NH ₄ OH, NaOH, KOH, HNO ₃ ). Upon subsequent drying and calcination of aluminum hydroxide, an active alumina support is obtained.

From (Dzisko V.A., Ivanova A.S. Basic methods for producing active aluminum oxide. // Izv. SB AN SSSR, Ser. Chemical sciences. 1985. 15, issue 5, p. 110-119) a method is known preparation of aluminum hydroxide pseudoboehmite structure (precursor of active alumina), which is obtained in the following way:

- in the "two-stage" method, part of the aluminum hydroxide is precipitated at room temperature ("cold" deposition - XO), and the other part is precipitated at 100 ° C ("hot" deposition - GO), after which both parts of XO and GO are mixed, maintained for a certain time, then filtered, washed and molded in the presence of acid with a specific acid module into aluminum hydroxide granules, then dried and calcined at the required temperature.

- precipitation of a solution of aluminum nitrate salt with an aqueous solution of ammonia at constant pH and temperature to provide certain properties of the obtained aluminum hydroxide, and, therefore, aluminum oxide.

It was shown that alumina obtained from hydroxide precipitated at room temperature and low pH has a unimodal pore size distribution with a predominant pore diameter of 8.0 nm; and obtained from hydroxide precipitated at 100 ° C, a bimodal pore size distribution. When the XO and GO sediments are mixed, the coarse dispersed GO aggregates form a framework, in the macropores of which a highly dispersed XO phase is located, as a result, a bimodal pore size distribution is formed.

It is known that supports for alumina-based catalysts most often have a small fraction of pores of large (more than 0.1 μm) diameter, which is associated with a low average pore radius.

In order to increase the proportion of large pores in the granules of the carrier, an extrudate or a powdered mixture of large particles or additives burned during calcination are added to the paste. At the same time, this often leads to a significant decrease in mechanical strength, an increase in the bulk density of the carrier, and a deterioration in the operational characteristics of the catalyst prepared on its basis.

In patent No. 2311959 (RU IPC B01J 37/02 (2006.01), B01J 23/88 (2006.01), B01J 29/40 (2006.01), B01J 29/18 (2006.01), B01J 32/00 (2006.01), C10G 45 / 06 (2006.01), publ. 10.12.2007) describes a method for producing an alumina carrier, including the deposition of aluminum hydroxide, the introduction of zeolite powder ZSM-5, mordenite, ΒΕΑ or Y in the Η-form or cationically substituted form in an amount of 5-15 wt. . % based on the finished product and peptizing additives of monobasic acid, molding by extrusion, drying and calcination at 450-600 ° C. The catalyst prepared on an alumina support contains oxides of molybdenum and cobalt and / or nickel. The catalyst based on this carrier has a high bulk density, a sufficiently large pore volume.

The disadvantages of this method is that the prepared carrier has a higher cost, because its preparation is carried out according to a more complex technology using a large number of expensive reagents.

From patent No. 2478428 (RU IPC B01J 23/882 (2006.01), B01J 37/02 (2006.01), B01J 23/883 (2006.01), B01J 21/02 (2006.01), B01J 21/04 (2006.01), B01J 21 / 06 (2006.01), B01J 27/02, 27/20, 27/047, (2006.01). B01J 32/00 (2006.01), B01J 37/04 (2006.01), B01J 37/20 (2006.01) publ. 04/10/2013 ) there is a known method of preparing a carrier, which includes molding a paste obtained by mixing AlOOH aluminum hydroxide powder, at least one titanium dioxide powder, at least one boron compound, water and a peptizing additive at a pressure of up to 10 MPa, followed by drying and calcination at a temperature up to 600 ° C. The finished carrier has a specific surface area of 150-300 m ² / g, a pore volume of 0.5-0.95 cm ³ / g and an average pore diameter of 7-22 nm, and representing particles with a cross section in the form of a trefoil with a diameter of the circumscribed circle 1, 0-1.6 mm and up to 20 mm long. The catalyst prepared on its basis contains molybdenum and cobalt or nickel in the form of complex compounds, for example, [M (H2O) x (L) y] 2 [Mo4O11 (C6H5O7) 2], where M = Co2 + and / or Ni2 +; L is a partially deprotonated form of citric acid C6H6 O7 or ammonia NH3, x = 0 or 2; y = 0; 1 or 2; and at least one oxygen-containing organic compound.

The disadvantages of this analogue is the complex technology for preparing the carrier and its higher cost, and it is also quite difficult to obtain carrier particles with a cross section in the form of a trefoil.

From patent No. 2362620 (RU MGR B01J 21/04 (2006.01), B01J 37/03 (2006.01), C01F 7/02 (2006.01), published July 27, 2009 Bull. No. 21), a method (method of single-stream deposition) for preparing the carrier is known - aluminum oxide, which is used in the manufacture of a hydrotreating catalyst. The method includes the precipitation of aluminum hydroxide from a solution of sodium aluminate with nitric acid, its stabilization, molding, drying and calcination, while sodium aluminate is treated with nitric acid for 100-120 minutes at a temperature of 58.0-65.0 ° C and a pH value of 7, 8-8.8, and stabilization is carried out for 60 minutes at a temperature of 58.0-62.0 ° C and a pH of 7.5-8.3. The carrier has the following physicochemical characteristics: bulk density (in terms of calcined at 550 ° C) 0.41-0.51 g / cm ³ , specific surface 254-257 m ² / g, total pore volume 0.58-0 72 cm ³ / g.

A disadvantage of the known alumina carrier is a lower pore volume and smaller specific surface area.

The closest (prototype) in technical essence is a method of preparing a carrier - alumina, described in patent No. 2303485 (RU IPC B01J 23/26 (2006.01) B01J 23/04 (2006.01) B01J 21/02 (2006.01) С07С 4/18 ( 2006.01), published July 27, 2007 Bul. No. 21). In the manufacture of the carrier, a fine powder of aluminum hydroxide in the amount of 15-50% by weight of the raw cake “aluminum cake” is introduced into the aluminum hydroxide “raw cake”, the introduction of a fine powder of aluminum hydroxide is carried out in the presence of an organic acid. Aluminum hydroxide - “raw cake” is made from “pellets” of boehmite “cold” and “hot” precipitation. Homogenization of a mixture of "cakes" of "cold" and "hot" precipitation is carried out in the presence of a peptizer according to known methods.

в общем объеме пор составляет 54,6%, доля широких пор радиусом

.Moreover, the porous structure is characterized by the fact that the proportion of pores with a radius

in the total pore volume is 54.6%, the proportion of wide pores with a radius

.

The disadvantages of the alumina carrier prepared according to the prototype are a higher bulk density, lower mechanical strength and specific surface area.

The objective of the present invention is to expand the range of methods for producing a carrier for catalysts for hydrotreating oil fractions with improved performance. The preparation of the carrier is active alumina using a simplified technology having a reduced bulk density, increased mechanical strength, a large specific surface area, and lower cost.

The technical result of the invention is:

- lower bulk density;

- increased water absorption;

- increase in mechanical strength;

- increase in specific surface area;

- an increase in the average pore size;

- simplification of cooking technology;

- reduction of material and energy costs and, as a result, cost reduction.

The technical result from the implementation of a method of preparing a carrier for a catalyst for hydrotreating petroleum fractions based on active alumina, comprising mixing a raw cake of aluminum hydroxide with aluminum hydroxide powder, processing the mixture with an organic acid solution, molding, drying and calcining, is achieved due to the fact that the hydroxide aluminum - "raw cake" is obtained by the method of single-line deposition, and the components are mixed in the ratio (wt.%) 1: 1-2.3.

In this case, a mixed aluminum hydroxide obtained by mixing aluminum hydroxide - "raw cake" and aluminum hydroxide powder is treated with solutions of nitric, acetic, phosphoric acids and triethylene glycol, and then stirred for 10-15 minutes. The formed carrier is dried at 120 ° C for 4 hours, then the temperature is raised to 550 ° C at 50 ° C per hour for 9 hours, and then calcined at 550 ° C for 8 hours.

A comparative analysis of the prototype and the present invention shows that common signs are the mixing of raw cake of aluminum hydroxide with aluminum hydroxide powder, processing the mixture with an organic acid solution, molding, drying and calcining.

A distinctive feature of the patented invention is that aluminum hydroxide - "raw cake" is obtained by the method of single-line deposition, and the components are mixed in the ratio (wt.%) 1: 1-2.3.

In this case, a mixed aluminum hydroxide obtained by mixing aluminum hydroxide - "raw cake" and aluminum hydroxide powder is treated with solutions of nitric, acetic, phosphoric acids and triethylene glycol, and then stirred for 10-15 minutes. The formed carrier is dried at 120 ° C for 4 hours, then the temperature is raised to 550 ° C at 50 ° C per hour for 9 hours, and then calcined at 550 ° C for 8 hours.

Aluminum hydroxide - “raw cake” is made by the method of single-stream deposition, which includes the precipitation of aluminum hydroxide from a solution of sodium aluminate with nitric acid. Precipitation is carried out at a pH of 6.0-8.5, a temperature of 40-80 ° C for 60-90 minutes. The single-threaded pulp deposition is washed with hot chemically purified water until the sodium content in the cake is not more than 0.010 mass. %, after which the precipitate is sent to the batch to prepare the media.

The process for manufacturing a carrier for a hydrotreating catalyst comprises the following steps:

1. Kneading, molding, drying the carrier.

2. Drying and calcining the carrier.

Kneading, molding and drying of the carrier is as follows. The calculated amount (in terms of the substance calcined at 650 ° С) of aluminum hydroxide of the crude cake brand, with a moisture content of 70-80 wt., Is loaded into the mixing machine. % obtained by the method of single-stream deposition, and the calculated amount (in terms of the substance calcined at 650 ° C) of aluminum hydroxide powder. The mass is stirred for 10-15 minutes, then a 59% solution of nitric acid, acetic acid, 85% solution of phosphoric acid, triethylene glycol and distilled water are added to it. The mass is mixed for 5-10 minutes, and then the batch is fed to a molding machine and molded into extrudates through a die with a hole diameter of 1.8-2.2 mm. Extrudates are dried on shelves for at least 24 hours, then loaded into an electric furnace.

Drying and calcining the carrier is carried out in an electric furnace according to the following mode:

- drying at 120 ° C for 4 hours;

- rise in temperature to 550 ° C at 50 ° C per hour for 9 hours;

- exposure at 550 ° C for 8 hours.

At the end of the calcination, the carrier is cooled to a temperature not exceeding 30 ° C and discharged. Visually determine the color of the obtained chilled product. The white color of the carrier indicates the completion of its preparation.

Technical characteristics of the reagents used to prepare the carrier.

1. Aluminum hydroxide "raw cake" is a paste-like mass of aluminum hydroxide containing 70 - 80 mass. % water.

2. Powdered aluminum hydroxide is a fine powder with a particle size of less than 4.0 nm.

For comparison and as a control, a prototype carrier was prepared. Preparation of carrier kneading is as follows. The kneading machine is loaded with 35 kg of pasty aluminum hydroxide - a “raw cake” made of “cold” and “hot” boehmite “pellets” and 15 kg of powdered aluminum hydroxide. The composition is stirred for 10 minutes until a homogeneous pasty mass is obtained, after which 3 kg of organic acid are added. The acid is introduced into the batch in the form of a dry powder, uniformly distributing the reagent throughout the batch, with constant stirring for 10-15 minutes. The resulting mixture is steamed to formability. The prepared batch is molded through a matrix with a hole diameter of 3.3-3.5 mm on a molding machine. The molded carrier is dried at a temperature of 150 ° C on a belt dryer and calcined in a calcination hopper at a temperature of 600-650 ° C. The calcined support is cooled.

Examples of media preparation are presented in table 1. Quality indicators of finished media are presented in table2.

From the data of table 2 it can be seen that the carrier prepared by the patented method is superior to the carrier of the prototype in all respects.

To prepare hydrotreating catalysts, the support obtained by the patented method is once impregnated with a mixed cobalt-molybdenum-phosphate solution. A mixed impregnating solution is obtained by dissolving ammonium molybdenum acid and cobalt nitrate in industrial water in the presence of phosphoric acid. As an example and for comparison, a catalyst was prepared on the basis of a carrier according to the prototype with a similar content of active components. In all catalysts, the content of MoO ₃ was 17.0% of the mass, CoO was 3.5% of the mass, and P ₂ O ₅ was 5.4% of the mass.

The catalysts were tested during hydrotreatment of diesel fractions in a flow-type microinstallation. About 100 cm ^{3 of} a hydrotreating catalyst, pre-ground to a particle size of 0.6-1.0 mm, were charged into a tubular reactor. On top and bottom of the catalyst, an inert material, quartz, was poured. Straight-run diesel fuel enriched with dimethyldisulfide (DMDS) with a sulfur content of at least 1 wt% was used as a grazing agent. At a pressure of 4.0 MPa, a hydrogen flow of 350 vol. N ₂ / about the feedstock straight-run diesel fuel enriched in DMDS is fed into the system at a speed of 1 hour ^-1 . The rate of temperature rise is constant at all stages and is 20 ° C per hour:

- rise in temperature to 240 ° C - 3 hours;

- exposure at 240 ° C - 5 hours;

- rise in temperature to 320 ° C - 4 hours;

- exposure at 320 ° C - 1 hour.

The raw material was a straight run diesel fraction (PDF) with the following characteristics: density at 15 ° C 0.842 kg / m ³ ; sulfur content of 0.8838% wt. (8838 ppm); boiling point 184 ° C; end boiling point 355 ° C.

As a raw material, PDF was also used with the following characteristics: density at 15 ° C 0.846 kg / m; sulfur content of 0.32% wt. (3200 ppm); boiling point 192 ° C; boiling point 98% volume 363 ° C and a mixture of the specified PDF containing 40% secondary components (12% light catalytic cracking gas oil (LGCC), 19% delayed coking diesel fraction (DPC), 9% delayed coking gasoline fraction (BFC)) with the following characteristics: density at 15 ° C 0.847 kg / m; sulfur content of 0.54% wt. (5400 ppm); boiling point 96 ° C; boiling point 98% of the volume of 357 ° C.

Test conditions: hydrogen pressure 4.0 MPa or 8.0 MPa, the ratio of hydrogen: feed 500 nl / l of raw materials, the volumetric feed rate (ISPS) of 1.0 h ^-1 or 2.0 h ^-1 , the temperature in the reactor 335 -370 ° C or 320-360 ° C.

Samples were taken by drop throttling of the hydrogenate every 6 hours under a layer of a 20% alkali solution. The alkalized samples of the hydrogenate, after washing with water, were dried with a solution of calcium chloride. In each sample, the density at 15 ° С and the mass fraction of sulfur were determined in accordance with GOST Ρ 52660 “Automotive fuels. Method for determination of sulfur content by X-ray fluorescence spectrometry with wavelength dispersion. "

The test conditions of the catalyst on the basis of the carrier prepared by the patented method during hydrotreatment of PDF with a sulfur content of 8838 ppm and the results are shown in table 3.

To assess the stability of the catalyst after testing at an ISPS 2.0 h ^-1 and a temperature of 370 ° C, activity was checked at an initial test temperature of 335 ° C. The total catalyst test time was 750 hours.

From the data presented in table 3 it follows:

- at an ISPS 1.0 h ^-1 and a process temperature of 345 ° C, the sulfur content in the hydrogenate is 9.0-11.0 mg / kg (average value - 10.3 mg / kg). With increasing process temperature to 350 ° C, the mass fraction of sulfur in the hydrogenate decreases and is 4.0-9.0 mg / kg (average value of 6.6 mg / kg);

- when OSPS 2.0 h ^{-1 the} catalyst provides hydrogenate with a mass fraction of sulfur less than 10.0 mg / kg at a process temperature of 370 ° C;

The catalyst showed stable operation for 750 hours. The mass fraction of sulfur in the hydrogenate obtained at 335 ° C at the beginning of the test was 33.0 mg / kg, at the end of the test it was 24.0 mg / kg, which indicates the stable operation of the catalyst and no reduction in catalytic properties.

The catalytic properties of the hydrotreating catalyst based on the carrier prepared by the patented method and the catalyst based on the carrier of the prototype were evaluated. In this case, raw materials No. 1 — PDF and raw materials No. 2 — PDF with the addition of 40% secondary components (12% LGAA, 19% DFAA, 9% BFAA) were used. The quality indicators of the components of raw materials and mixed raw materials are shown in table 4. The test conditions of the samples of the catalysts and the results are shown in table 5.

From the data of table 5 it follows that the catalyst based on the prototype carrier provides hydrogenation with a mass fraction of sulfur of 10 ppm and at a temperature of 345 ° C (hydrotreating PDF) and 350 ° C (hydrotreating mixed raw materials with the addition of 40% secondary components). Catalysts based on a carrier prepared by the patented method provide hydrogenation with a mass fraction of sulfur of less than 10 ppm at a lower temperature (325 ° C). With an increase in the volumetric feed rate to 2.0 h ^{−1, the} temperature required to obtain a hydrogenate with a sulfur mass fraction of less than 10 ppm increases to 345-350 ° C.

Claims (3)

1. A method of preparing a carrier for a catalyst for hydrotreating petroleum fractions based on active alumina, comprising mixing a raw cake of aluminum hydroxide with aluminum hydroxide powder, treating the mixture with an organic acid solution, molding, drying and calcining, characterized in that the aluminum hydroxide is "raw" cake "is obtained by the method of single-line deposition, which includes the precipitation of aluminum hydroxide from a solution of sodium aluminate with nitric acid, and the components are mixed in the ratio (wt.%) 1: 1-2.3. 2. A method of preparing a carrier for a catalyst for hydrotreating petroleum fractions according to claim 1, characterized in that the mixed aluminum hydroxide obtained by mixing aluminum hydroxide - “raw cake” and aluminum hydroxide powder is treated with a solution of nitric, acetic, phosphoric acid and triethylene glycol, after which mix for 10-15 minutes. 3. A method of preparing a carrier for a catalyst for hydrotreating oil fractions according to claim 1, characterized in that the formed carrier is dried at 120 ° C for 4 hours, the temperature is subsequently raised to 550 ° C at 50 ° C per hour for 9 hours, then calcined at 550 ° C for 8 hours.