RU2566307C1 - Catalyst for hydrofining diesel fractions and method for production thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to an aluminium oxide-based catalyst for hydrofining diesel fractions and contains, wt %: nickel or cobalt oxide - 3.0-7.0, molybdenum oxide (MoO₃) - 16-22.0, including: in the form of molybdenum trioxide - 8-11, phosphomolybdic acid in terms of molybdenum trioxide - 8-11, tungsten oxide (WO₃) - 12.0, phosphorus - 0.37, aluminium oxide - the balance. The catalyst is obtained by modifying a support by successively adding to aluminium hydroxide a solution of phosphotungstic acid and aqueous ammonium paramolybdate solution, extrusion moulding, drying and annealing. The annealed modified support is impregnated with a combined solution of phosphomolybdic acid and cobalt or nickel salts for 1.5-2 hours while stirring and heating to 55-60°C. The obtained catalyst is dried and annealed.

EFFECT: high catalytic activity, which provides high output of a stable hydrogenation product and obtaining diesel fuels with ultralow sulphur content.

2 cl, 1 tbl, 6 ex

Description

The invention relates to catalytic chemistry, in particular to the preparation of hydrotreating catalysts for petroleum feedstocks, and can be used in the refining industry.

In the last decade, environmental and operational requirements for the quality of oil refining products have been increasing. Hydrotreating processes can improve the performance of finished products so that they meet the requirements of quality standards and environmental emissions (sulfur content in particular), and prepare raw materials for other refinery processing plants, such as isomerization, reforming, catalytic cracking, the catalysts of which sensitive to impurities of sulfur (metal catalysts), nitrogen (acid catalysts) and metals (all types of catalysts).

The preparation of catalysts that ensure the predominant hydrotreating reactions and have increased activity is achieved by controlling the chemical composition (selection of appropriate carriers, active components and their contents), by varying the methods for preparing the catalyst system and methods for introducing active components, modifiers and promoters. A significant effect on the effectiveness of the catalysts is also exerted by the activation conditions (calcination and sulfidation), the size and shape of the granules. Improvement of hydrotreating catalysts is carried out in two main directions - modification of the active phase and development of a method for introducing active components.

A known catalyst for carrying out the process of hydrodesulfurization of the diesel fraction and a method for its preparation. The catalyst contains alumina as a carrier, modifiers citric acid and / or boron compounds, and the active components cobalt and molybdenum oxides. To prepare the system, the method of a single impregnation of a carrier with an impregnating solution obtained by dissolving in water or an aqueous solution of ammonia the following compounds is used: citric acid, ammonium paramolybdate (NH ₄ ) ₆ Mo ₇ O ₂₄ × 4H ₂ O, cobalt compounds, boron compounds, while such order and conditions for dissolving the components to ensure the formation of complex compounds in the solution. The product is diesel fuel with a sulfur content of about 35 ppm (99.7% desulfurization). RU 2313392 C1, 12/27/2007.

The disadvantages of the catalyst and the method of its production include increased gas formation during calcination of the catalyst at a temperature of 400 ° C as a result of decomposition of citric acid, which can lead to cracking of the catalyst granules, as well as low activity in the process of hydrodesulfurization of the diesel fraction (residual sulfur content in diesel fuel 35 -50 ppm).

Known alumina-cobalt-molybdenum catalyst for hydrotreating petroleum feedstocks containing phosphorus oxide as a modifier. The catalyst is prepared in the following way: active components are introduced into the carrier - aluminum hydroxide at the kneading stage from a solution containing molybdenum, phosphorus and cobalt or nickel compounds, prepared initially from ammonium paramolybdate, phosphoric acid and hydrogen peroxide in a ratio of Mo: P of no more than 2.5 g-eq / g-eq and H ₂ O ₂ : Mo not more than 0.4 mol / g-eq, followed by the introduction into the resulting solution of ammonium peroxomolybdophosphate composition [P ₂ Mo ₅ O _23-x (O ₂ ) _x ] ( NH ₄ ) ₆ , where x = 1 or 2, cobalt or nickel nitrate while maintaining the pH of the solution 1.0-2.6 with total the ratio in solution in terms of g-eq. Ni (Co): Mo: P = (0.8-1.8) :( 1.1: 2.5): 1. The resulting paste is formed by extrusion, and the extrudates are dried and calcined. RU 2103065, 01.27.1998.

The disadvantage of the proposed method for the preparation of the catalyst is its low desulfurization ability.

A known catalyst for hydrodesulfurization of diesel fractions containing inorganic oxide (preferably aluminum oxide), molybdenum trioxide, phosphorus and cobalt or nickel oxide. The catalyst is prepared in several stages: first, a hydrotreating catalyst of the composition Co / Mo / P / Ni is prepared (2.9% by mass of Co, 12.0% by mass of Mo, 0.09% by mass of P and 0.02% by mass of Ni), which is finely it is crushed, then the finely divided freshly prepared catalyst is mixed with molybdenum trioxide powder, an aqueous solution of cobalt, inorganic oxide powder (preferably alumina), a kneading step is carried out, followed by molding, to obtain a granular catalyst that is dried and calcined. WO 2008016971 A2, 02/07/2008.

The disadvantages of this catalyst include a complex sequence of procedures for its preparation, in particular the multi-stage calcination and grinding of a freshly prepared catalyst based on aluminum oxide containing cobalt, molybdenum and nickel oxides, as well as phosphorus.

Known alumina-cobalt-molybdenum catalyst for hydrotreating petroleum fractions, in which a mixture of alumina and borophosphate of variable composition formed at the stage of calcination of a carrier of H ₃ BO ₃ and H ₃ PO _{4 is} used as a carrier, with the following component content, mass%: phosphorus-molybdenum heteropoly complex, P · [(MoO ₃ ) ₁₂ ] - 14.3-27.5; cobalt oxide CoO - 3.2-8.5; aluminum oxide - 56.5-81.6; borophosphate - 0.9-7.5. The catalyst preparation method includes: preparing the carrier by introducing boric and phosphoric acids into the aluminum hydroxide at the kneading stage, followed by molding the resulting mass, drying and calcining, once impregnating the carrier with a joint impregnating solution of group VIII and VI metal compounds containing a molybdenum heteropoly compound, cobalt nitrate and a stabilizer solution - an organic dibasic acid selected from citric, tartaric or ascorbic acids, at a pH of 1.5–5.0, followed by drying at 110 -200 ° C. RU 2497586 C1, 01/20/2013.

The disadvantages of this catalyst and the method for its preparation include low catalyst activity (residual sulfur content in the diesel fraction of 39-50 ppm), the use of organic acids at the stage of preparation of the catalyst, which can lead to the destruction of the granules of the catalyst system during heat treatment, as well as low temperature heat treatment at the final stage of catalyst preparation, which can lead to destruction of the obtained complex during operation (temperature 360 ° C) and further regeneration and a catalyst (temperatures over 450 ° C).

Closest to the proposed invention is a catalyst for hydrotreating oil fractions, containing, wt%: alumina - 76.92-85.98, molybdenum oxide - 10-14, nickel oxide or cobalt oxide - 3-5, as a compound of tungsten and silicon - silicon-tungsten complex - 1.02-4.08. A method for preparing a catalyst includes precipitation of aluminum hydroxide, peptization, introduction of a molybdenum compound, extrusion molding, drying, calcination, impregnation of a calcined aluminum-molybdenum support with a combined aqueous solution of tungsten acid and nickel or cobalt nitrate, drying and calcination at a temperature of 500 ° C for 2 hours. RU 2147255 C1, 01/27/2000.

The disadvantages of this catalyst and the method of its preparation include low activity in hydrodesulfurization reactions - the maximum degree of desulfurization is 96.5% rel.

The technical problem solved by the claimed group of inventions is to create a catalyst for hydrotreating diesel fractions with increased activity in the target reactions occurring during hydrodesulfurization of diesel fractions, and a method for its production, which ensures a decrease in the residual amount of sulfur and a high yield of stable hydrogenate.

The technical result from the implementation of the claimed group of inventions is to increase the catalytic activity of the catalyst, which provides a high yield of stable hydrogenate and the production of diesel fuels with ultra low sulfur content (not more than 7 ppm).

The technical problem is solved in that the catalyst for hydrotreating diesel fractions, containing a modified aluminum-molybdenum support, cobalt or nickel oxide, tungsten, additionally contains phosphorus in the form of tungsten and phosphoromolybdenum acids, tungsten contains in the form of tungsten oxide, and molybdenum oxide in the form of trioxide in molybdenum in the form of phosphoromolybdic acid in terms of molybdenum trioxide, in the following ratio of components, mass%:

Cobalt or nickel oxide 3.0-7.0 Molybdenum oxide 16-22 including: in the form of molybdenum trioxide 8-11 as phosphoromolybdic acid in terms of molybdenum trioxide 8-11 Tungsten oxide 6-12 Phosphorus 0.23-0.37 Aluminium oxide rest

In accordance with the task, a method for producing the claimed catalyst has been developed, namely, the carrier is modified by sequentially introducing a solution of phosphoric tungsten acid and an aqueous solution of ammonium paramolybdate into the mass of aluminum hydroxide, molding by extrusion, drying and calcining, the resulting modified carrier is impregnated with a combined solution of phosphoromolybdenum acid and cobalt or nickel salts for 1.5-2 hours with stirring and heating to a temperature of 55-60 ° C, half enny catalyst dried and calcined.

The efficiency of the catalyst was evaluated in the process of hydrotreating a straight-run diesel fraction by passing a hydrogen-containing gas and feed with a volume ratio of hydrogen to feed from 350: 1 through a fixed catalyst bed loaded into a tubular reactor with a bulk velocity of 1.0-2.0 h ^-1 temperature range 320-380 ° C under a pressure of 5.0 MPa by the residual sulfur content in a stable hydrogenate.

Before carrying out the hydrotreatment process, the catalyst was sulfidated with dimethyl disulfide in a stream of hydrogen at a temperature of 300 ° C.

Example 1

The example illustrates a method for producing alumina-cobalt-molybdenum catalyst based on alumina. To obtain the carrier using aluminum hydroxide - boehmite.

A sample of the composition catalyst, mass%: cobalt oxide (CoO) - 3.0, molybdenum oxide (MoO ₃ ) - 16.0, including: in the form of molybdenum trioxide (MoO ₃ ) - 8.0, phosphoromolybdenum acid in terms of molybdenum oxide (MoO ₃ ) - 8.0, tungsten oxide (WO ₃ ) - 6.0, phosphorus - 0.23, aluminum oxide - the rest is prepared in the following way.

98.1 g of aluminum hydroxide powder is suspended in 150 ml of water. A peptizing solution consisting of 30 ml of water, 3.5 ml of 65% nitric and 6.67 g of phosphoric tungsten acid is poured to the suspended mass, and mixed until a homogeneous mass.

9.47 g of ammonium paramolybdate are dissolved in 70 ml of hot water with vigorous stirring. The resulting solution is added to the peptized mass of aluminum hydroxide, thoroughly mixed and extruded on a piston extruder through a die with a diameter of 1.5 mm. The extrudates are held in air for 6 hours and placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a speed of 2 ° C / min to 550 ° C. At a temperature of 550 ° C incubated for 4 hours

100 g of the calcined support are immersed in 90 ml of an impregnation solution taken with a 1.5-fold excess and containing 13.35 g of phosphoromolybdenum acid and 17.48 cobalt nitrate. The carrier is impregnated for 2 hours while heating to 55 ° C and stirring, the remainder of the solution is decanted. The catalyst is dried in a stream of air. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours, after which the catalyst is calcined at a temperature of 550 ° C.

Example 2

The example illustrates a method for producing alumina-cobalt-molybdenum catalyst based on alumina. To obtain the carrier using aluminum hydroxide - boehmite.

Sample catalyst composition, mass%: cobalt oxide (CoO) - 5.0, molybdenum oxide (MoO ₃ ) - 19.0, including: in the form of molybdenum trioxide (MoO ₃ ) - 9.5, phosphoromolybdenum acid in terms of molybdenum trioxide (MoO ₃ ) - 9.5, tungsten oxide (WO ₃ ) - 9.0, phosphorus - 0.3, aluminum oxide - the rest.

87.5 g of aluminum hydroxide powder is suspended in 150 ml of water for three minutes and a peptizing solution consisting of 30 ml of water, 3.12 ml of 65% nitric acid and 10.0 g of phosphoric tungsten acid is quickly poured and mixed until homogeneous .

11.2 g of ammonium paramolybdate are dissolved in 83 ml of hot water with vigorous stirring. The resulting solution is added to the peptized mass of aluminum hydroxide, thoroughly mixed and extruded on a piston extruder through a die with a diameter of 1.5 mm. The extrudates are kept in air for 6 hours, the granule length is adjusted to 3-5 mm and placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a speed of 2 ° C / min to 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

100 g of the calcined support are immersed in 90 ml of an impregnation solution taken with a 1.5-fold excess and containing 15.8 g of phosphoromolybdenum acid and 29.18 cobalt nitrate. The carrier is impregnated for 1.5 hours while heating to 60 ° C and stirring, the remainder of the solution is decanted. The catalyst is dried in a stream of air. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours, after which the catalyst is calcined at a temperature of 550 ° C.

Example 3

The example illustrates a method for producing alumina-cobalt-molybdenum catalyst based on alumina. To obtain the carrier using aluminum hydroxide - boehmite.

Sample catalyst composition, mass%: cobalt oxide (CoO) - 7.0, molybdenum oxide (MoO ₃ ) - 22.0 including: in the form of molybdenum trioxide (MoO ₃ ) - 11.0 phosphoromolybdenum acid in terms of molybdenum trioxide (MoO ₃ ) - 11.0, tungsten oxide (WO ₃ ) - 12.0, phosphorus - 0.37, aluminum oxide - the rest.

76.9 g of aluminum hydroxide powder is suspended in 150 ml of water for three minutes and a peptizing solution consisting of 30 ml of water, 2.74 ml of 65% nitric acid and 13.3 g of tungsten phosphoric acid is rapidly poured and mixed until homogeneous .

13.0 g of ammonium paramolybdate are dissolved in 96 ml of hot water with vigorous stirring. The resulting solution is added to the peptized mass of aluminum hydroxide, thoroughly mixed and extruded on a piston extruder through a die with a diameter of 1.5 mm. The extrudates are kept in air for 6 hours, the granule length is adjusted to 3-5 mm and placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a speed of 2 ° C / min to 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

100 g of the calcined support are immersed in 90 ml of an impregnation solution taken with a 1.5-fold excess and containing 18.3 g of phosphoromolybdenum acid and 40.9 cobalt nitrate. The carrier is impregnated for 2 hours while heating to a temperature of 57 ° C and stirring, the remainder of the solution is decanted. The catalyst is dried in a stream of air. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours, after which the catalyst is calcined at a temperature of 5500C.

Example 4

The example illustrates a method for producing alumina-cobalt-molybdenum catalyst based on alumina. To obtain the carrier using aluminum hydroxide - boehmite.

Sample catalyst composition, mass%: nickel oxide (NiO) - 3.0, molybdenum oxide (MoO ₃ ) - 16.0, including: in the form of molybdenum trioxide (MoO ₃ ) - 8.0, phosphoromolybdenum acid in terms of molybdenum trioxide (MoO ₃ ) - 8.0, tungsten oxide (WO ₃ ) - 6.0, phosphorus - 0.23, aluminum oxide - the rest is prepared in the following way.

98.1 g of aluminum hydroxide powder is suspended in 150 ml of water. A peptizing solution consisting of 30 ml of water, 3.5 ml of 65% nitric acid and 6.67 g of phosphoric tungsten acid is poured to the suspended mass, and mixed until a homogeneous mass.

9.47 g of ammonium paramolybdate are dissolved in 70 ml of hot water with vigorous stirring. The resulting solution is added to the peptized mass of aluminum hydroxide, thoroughly mixed and extruded on a piston extruder through a die with a diameter of 1.5 mm. The extrudates are held in air for 6 hours and placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a speed of 2 ° C / min to 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

100 g of the calcined support are immersed in 90 ml of an impregnation solution taken with a 1.5-fold excess and containing 13.35 g of phosphoromolybdenum acid and 17.48 g of nickel nitrate. The carrier is impregnated for 1.7 hours while heating to a temperature of 58 ° C and stirring, the remainder of the solution is decanted. The catalyst is dried in a stream of air. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours, after which the catalyst is calcined at a temperature of 550 ° C.

Example 5

The example illustrates a method for producing alumina-cobalt-molybdenum catalyst based on alumina. To obtain the carrier using aluminum hydroxide - boehmite.

Sample catalyst composition, wt%: nickel oxide (NiO) - 5.0, molybdenum oxide (MoO ₃ ) - 19.0, including: in the form of molybdenum trioxide (MoO ₃ ) - 9.5, phosphoromolybdenum acid in terms of molybdenum trioxide (MoO ₃ ) - 9.5, tungsten oxide (WO ₃ ) - 9.0, phosphorus - 0.3, aluminum oxide - the rest is prepared in the following way.

87.5 g of aluminum hydroxide powder is suspended in 150 ml of water for three minutes and a peptizing solution consisting of 30 ml of water, 3.12 ml of 65% nitric acid and 10.0 g of tungsten phosphoric acid is rapidly poured and mixed until homogeneous masses.

11.2 g of ammonium paramolybdate are dissolved in 83 ml of hot water with vigorous stirring. The resulting solution is added to the peptized mass of aluminum hydroxide, thoroughly mixed and extruded on a piston extruder through a die with a diameter of 1.5 mm. The extrudates are kept in air for 6 hours, the granule length is adjusted to 3-5 mm and placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a speed of 2 ° C / min to 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

100 g of the calcined support are immersed in 90 ml of an impregnation solution taken with a 1.5-fold excess and containing 15.8 g of phosphoromolybdenum acid and 29.18 g of nickel nitrate. The carrier is impregnated for 1.6 hours while heating to a temperature of 59 ° C and stirring, the remainder of the solution is decanted. The catalyst is dried in a stream of air. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours, after which the catalyst is calcined at a temperature of 550 ° C.

Example 6

The example illustrates a method for producing alumina-cobalt-molybdenum catalyst based on alumina. To obtain the carrier using aluminum hydroxide - boehmite.

A sample of the composition catalyst, mass%: nickel oxide (NiO) - 7.0; molybdenum oxide (MoO ₃ ) - 22.0; including: in the form of molybdenum trioxide (MoO ₃ ) - 11, molybdenum phosphorus acid in terms of molybdenum trioxide (MoO ₃ ) - 11, tungsten oxide (WO ₃ ) - 12.0, phosphorus - 0.37, aluminum oxide - the rest .

76.9 g of aluminum hydroxide powder is suspended in 150 ml of water for three minutes and a peptizing solution consisting of 30 ml of water, 2.74 ml of 65% nitric acid and 13.3 g of tungsten phosphoric acid is rapidly poured and mixed until homogeneous .

13.0 g of ammonium paramolybdate are dissolved in 96 ml of hot water with vigorous stirring. The resulting solution is added to the peptized mass of aluminum hydroxide, thoroughly mixed and extruded on a piston extruder through a die with a diameter of 1.5 mm. The extrudates are kept in air for 6 hours, the granule length is adjusted to 3-5 mm and placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a rate of 2 ° C / min to a temperature of 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

100 g of the calcined support are immersed in 90 ml of an impregnation solution taken with a 1.5-fold excess and containing 18.3 g of phosphoromolybdenum acid and 40.9 g of nickel nitrate. The carrier is impregnated for 1.5 hours while heating to a temperature of 60 ° C and stirring, the remainder of the solution is decanted. The catalyst is dried in a stream of air. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours, after which the catalyst is calcined at a temperature of 550 ° C.

The efficiency of the catalysts synthesized according to examples 1-6 was evaluated in the process of hydrotreating a straight run diesel fraction of 157-275 ° C with a sulfur content of 0.663 mass% by passing hydrogen-containing gas and diesel fraction with a volume ratio of hydrogen to feed of 350: 1 through a fixed catalyst bed, loaded into a tubular reactor with a space velocity of 1-2 h ^-1 in the temperature range 320-380 ° C under a pressure of 5.0 MPa by the residual sulfur content in the hydrogenate.

The performance of the hydrotreatment of diesel fractions carried out using samples of the catalysts corresponding to the invention are presented in the table.

From the table it follows that the proposed catalyst for hydrotreating a diesel fraction is characterized by high activity in hydrodesulfurization reactions in the hydrotreatment of diesel fractions.

Claims (2)

1. The catalyst for hydrotreating diesel fractions containing a modified aluminum-molybdenum carrier, cobalt or nickel oxide, tungsten, characterized in that the catalyst further comprises phosphorus in the form of tungsten and phosphoromolybdenum acids, tungsten contains in the form of tungsten oxide, and molybdenum oxide in the form of trioxide in the form of phosphoromolybdic acid in terms of molybdenum trioxide, in the following ratio, wt. %:
Cobalt or nickel oxide 3.0-7.0 Molybdenum oxide 16-22 including: in the form of molybdenum trioxide 8-11 as phosphoromolybdic acid in terms of molybdenum trioxide 8-11 Tungsten oxide 6-12 Phosphorus 0.23-0.37 Aluminium oxide rest 2. A method of producing a catalyst for hydrotreating diesel fractions according to claim 1, which consists in modifying the support by sequentially adding to the mass of aluminum hydroxide a solution of phosphoric tungsten acid and an aqueous solution of ammonium paramolybdate, molding by extrusion, drying and calcining, the resulting modified support is impregnated with a phosphorus molybdenum joint solution acid and salts of cobalt or nickel for 1.5-2 hours with stirring and heating to a temperature of 55-60 ° C, the resulting catalyst pro sutured and baked.