RU2313389C1 - Catalyst, method for preparation thereof, method for preparing carrier for this catalyst, and diesel fraction desulfurization process - Google Patents

Abstract

FIELD: catalysts in petroleum processing and petrochemistry.

SUBSTANCE: invention relates to catalysts for extensive hydrofining of hydrocarbon stock, in particular diesel fractions, to remove sulfur compounds. Catalyst of invention, intended for diesel fraction desulfurization processes, comprises active component, selected from oxides of group VIII and VIB metals and phosphorus, dispersed on alumina support, said alumina support containing 5-15% of montmorillonite, so that total composition of catalyst is as follows, wt %: molybdenum oxide MoO₃ 14.0-29.0, cobalt oxide CoO and/or nickel oxide 3-8, phosphorus 0.1-0.5, and support - the balance, molar ratio Mo/Co and/or Mo/Ni being 1.3-2.6 and P/Mo 0.08-0.1. Preparation of catalyst support consists in precipitation of aluminum hydroxide and addition of montmorillonite with moisture content 55-70% to water dispersion of aluminum hydroxide in amount such as to ensure 5-15% of montmorillonite in finished product, after which resulting mixture is extruded and extrudate is calcined at 500-600°C to give support characterized by specific surface 200-300 m²/g, pore volume 0.5-0.9 cm³/g, and prevailing pore radius 80-120 Å. Catalyst preparation comprises impregnation of calcined support with complex solution of group VIII and VIB metal salts and phosphorus followed by heat treatment in air or nitrogen flow at temperature not exceeding 200°C, impregnation solution notably containing molybdenum oxide and cobalt and/or nickel carbonate at Mo/Co and/or Mo/Ni molar ratio 1.3-2.6 stabilized with orthophosphoric acid and citric acid to P/Mo molar ratio between 0.008 and 0.1 at medium pH between 1.3 and 3.5. Described is also diesel fraction hydrodesulfurization process involving passage of diesel fraction through bed of above-defined catalyst.

EFFECT: intensified diesel fraction desulfurization.

9 cl, 3 tbl, 19 ex

Description

The invention relates to the field of chemistry, namely to catalysts for the deep hydrotreatment of hydrocarbon feedstocks, in particular diesel fractions, from sulfur compounds of a number of thiophene and its derivatives: benzothiophene, dibenzothiophene, alkyl dibenzothiophene and 4,6-dialkyl dibenzothiophene and other sulfur-containing aromatic compounds, and can be used in the refining and petrochemical industries.

Known catalysts for hydrotreating diesel fractions from sulfur compounds contain catalytically active compounds of molybdenum and / or tungsten and cobalt and / or nickel deposited on the surface of an inert porous support in oxide or sulfide form.

A known method for the preparation of hydrodesulfurization catalysts containing Co (Ni) -Mo (W) compounds dispersed on alumina is the extrusion of a catalytically active mass with subsequent stages of drying, heat treatment and preliminary activation by sulfidation. In this case, the active component is added to aluminum hydroxide with boehmite or pseudoboehmite structure (RU 2137541, B01J 23/88. 09/20/99; 2074025, B01J 21/04, 02/27/97). As precursors of the active component, water-soluble salts of molybdenum or tungsten, mainly ammonium molybdenum acid, and cobalt or nickel, mainly nitrates (RU 2137541, B01J 23/88, 09/20/99) or a complex solution of metal salts of groups VIII and VI stabilized with phosphoric acid are used acid at pH-0.5-2.5 (RU 2074025, B01J 21/04, 02.27.97). The main disadvantage of this method is its low hydrodesulfurization activity, which does not allow to obtain low-sulfur diesel fuel (with a sulfur content of less than 300 ppm). A big disadvantage of these catalysts is also the low mechanical strength, which is a significant limitation for the operation of the catalyst in hydrotreatment plants.

The patent RU 2074025 describes a method for producing a hydrotreating catalyst for oil fractions, containing, wt.%: 14-21 molybdenum oxide, 3-8 nickel oxide or cobalt oxide, 0.5-6 phosphoric anhydride, aluminum oxide the rest, by applying compounds of active components on alumina by coprecipitation of metal salts of groups VIII and VI of the Periodic system and phosphorus, followed by molding the catalytic mass in the form of extrudates, drying and calcining the obtained granules, characterized in that the application of the active components is carried out by introducing them in aluminum hydroxide in the form of a complex solution of metal salts of groups VIII and VI, stabilized with phosphoric acid, provided that the pH of the phosphoric acid solution is 0.5-2.5 at 40-60 ° C.

RU 2137541 describes a method for producing a catalyst for hydrotreating petroleum feeds, including precipitation of aluminum hydroxide by the sulfate method, introduction of molybdenum and nickel salts into aluminum hydroxide, extrusion molding, drying, calcination, characterized in that the aluminum hydroxide is heated at a temperature of 50 before introducing the active components -80 ° C with continuous stirring, then ammonium paramolybdate and nickel nitrate are introduced in stages with intermediate heating of molybdenum-containing aluminum hydroxide at constant temperature stirring for 30 minutes and treat the resulting mass with a moisture content of 68-70 wt.% monobasic mineral acid (nitric or hydrochloric) to a pH of between 4-6.

Another known method for the preparation of hydrodesulfurization catalysts containing Co (Ni) -Mo (W) compounds dispersed on the surface of a support is the method of impregnating an inert support with solutions of the compounds of the precursors of the active component, followed by drying, calcining and sulfidation. As porous inert supports, calcined extrudates based on alumina and / or silica are usually used. To control the acid-base properties, the carriers are modified with additives of ultra-stable zeolite Y (in an amount of 5-7 wt.%), Titanium, zirconium and amorphous aluminosilicates, as well as with the addition of phosphorus, boron and others. For the preparation of catalysts for hydrodesulfurization of diesel fractions, it is recommended to use calcined supports having a specific surface area of 200-300 m ² / g, a pore volume of 0.5-0.9 cm ³ / g and an apparent density of 0.5-0.8 g / cm ³ in this case, after applying Co (Ni) -Mo (W) of the active component and calcining, the specific surface of the catalyst will vary between 150-275 m ² / g, pore volume 0.4-0.8 cm ³ / g, and apparent density 0.5-1.0 g / cm ³ (US 3840472, B01J 27/19, C10G 45/08, 8.10.74). The extrudates are usually in the form of cylinders or trefoils in sizes of 1/8, 1/16 or 1/32 inch. A number of patents stipulate the optimal pore size distribution, which ensures the highest activity in hydrodesulfurization of oil fractions. In particular, for cleaning diesel fractions, a narrow pore size distribution is required, while pores with a diameter of 70-130 Å should be at least 75% of the total pore volume (US 4818743, B01J 23/85, 04.04.89; 4879265, B01J 23/24, 11/07/89), and the fraction of pore volume with a diameter of more than 130 Å should not exceed 10% (US 4818743). This pore size distribution provides not only high accessibility of sulfur compounds to the surface of the active component, but also reduces the possibility of coking of pores.

Application of the active component is carried out both by sequential impregnation from separate solutions, and by a single impregnation from joint solutions. To prepare impregnating solutions, molybdenum and tungsten oxides, ammonium salts of molybdenum and tungsten acids (paramolybdate and ammonium paratungstate), molybdenum or tungsten acids, in some cases molybdenum or tungsten acid, are usually used. In order to increase the solubility of molybdenum and tungsten compounds in water, mineral acids, mainly phosphoric and orthophosphoric acids, are added to the impregnation solutions. Additives of mineral acids also make it possible to increase the stability of joint impregnating solutions containing compounds of groups VIII and VI to agglomeration and precipitation of crystallized precipitates. Another way to increase the solubility of molybdenum compounds (mainly molybdenum oxide and ammonium molybdenum acid) and the stability of joint impregnating solutions containing group VIII and VI compounds is to use concentrated aqueous ammonia solutions. Both water-soluble and sparingly soluble compounds are used as cobalt and nickel precursor compounds, most often nitrate, sulfate, acetate, citrate, carbonate, hydroxide and cobalt and / or nickel oxide. The main disadvantage of joint impregnation solutions containing compounds of groups VIII and VI is their low stability in the presence of an excess of phosphoric acid, nitrate anion (NO ₃ ^- ) and ammonium cation due to the possibility of formation and precipitation of cobalt (nickel) and ammonium phosphates.

Known bimetallic Co-Mo and Ni-Mo catalysts containing 8-10 wt.% MoO ₃ and 3 wt.% CoO supported on alumina supports provide effective purification of diesel fractions from sulfur compounds, mainly mercaptans, dialkyl disulfides, thiophene and a number of its derivatives, up to the level of 500 ppm sulfur. Sulfur remaining in diesel fuel after the hydrodesulfurization process on these catalysts is part of the most stable organosulfur compounds, such as substituted alkyl dibenzothiophenes with one or two alkyl groups located in the β-position to the sulfur atom. Therefore, it is the conversion of substituted alkyl dibenzothiophenes that determines the degree of hydrodesulfurization of the feedstock in the deep hydrotreatment of petroleum fractions.

One way to achieve deep hydrodesulfurization of diesel fractions is to increase the pressure and temperature of the process, which allows the use of well-known Co (Ni) -Mo (W) catalysts in the process. However, an increase in the pressure and temperature of the process leads to the deactivation of the catalysts both by increasing the partial pressure of hydrogen sulfide in the gas mixture, which is especially characteristic of Ni-Mo catalyst, and by coking the surface of the catalyst with hydrocarbon components of diesel fuel. The disadvantage of this method is also an increase in the cracking activity of Co (Ni) -Mo (W) catalysts at elevated temperatures, which inevitably leads to a decrease in the yield of liquid petroleum products and a decrease in the cetane number of diesel fuel.

Another way to achieve a deep degree of purification is to optimize the composition of the catalyst. It is known that in the case of β-dialkyl dibenzothiophenes, the rate of conversion along the hydrogenolysis pathway of the CS bond is greatly slowed down due to severe steric hindrances in their adsorption on the surface of the active center. Therefore, for carrying out deep hydrodesulfurization processes, it is necessary to use carriers with a developed porous structure and a narrow pore size distribution, while the proportion of pores with a size of 75-130 Å should be at least 75% of the total pore volume (US 4818743, 4879265, 2003/0173256). Removal of steric difficulties arising from the adsorption of β-dialkyl dibenzothiophenes is achieved by optimizing the composition of the active complex, in particular, by increasing the number of so-called “CoMoS-II” centers consisting of molybdenum sulfide, MoS ₂ , which has a layered structure doped along the perimeter with promoter cations, Co or Ni. The increase in the number of "CoMoS-II" centers is usually achieved by increasing the content of molybdenum compounds in the catalyst to 18-22 wt.% (US 2003/0173256), and in some cases up to 29 wt.% (US 2006/0054536). Optimization of pH and composition of impregnating solutions by introducing acid additives in molybdenum-containing solutions (H ₃ PO ₄ , H ₃ BO ₃ , etc.] helps to ensure uniform distribution of the high content of the active complex over the support (up to 6 Mo atoms per nm ² Al ₂ O ₃ ). US 3755196, 4392985, 4879265]. For the formation of "CoMoS-II" centers, it is also necessary to exclude the formation of crystallized phases Co ₃ O ₄ and CoAl ₂ O ₄ at the stage of impregnation and heat treatment, since the latter turn into sulfur-containing medium (sulfidation) into sulfide cob lta, Co ₉ S _8, in an inactive hydrodesulfurization reaction Education crystallized phases Co ₃ O ₄ and CoAl ₂ O ₄ reduced by the introduction of organic additives, such as citric acid (US 2003/0173256; 2006/0054536)., to the impregnating solution, calcining the active complex at temperatures not higher than 300 ° C (US 2003/0173256; 2006/0054536) and by sulfidation of the catalyst under “mild” conditions (US 4879265; 2003/0173256).

The removal of β-dialkyl dibenzothiophenes can be carried out through the stage of preliminary conversion to more reactive compounds along the routes: hydrogenation of one of the benzene rings, isomerization (transfer of alkyl groups from the β-position to γ-), dealkylation (removal of one of the alkyl groups), C break -C bond thiophene ring. The occurrence of these reactions is traditionally achieved for Co (Ni) -Mo (W) catalysts by increasing the acid properties of alumina carriers by modifying them with additives of titanium, zirconium and silicon oxides, additives of amorphous aluminosilicates and zeolites, as well as anions of phosphoric and / or boric acids. The conversion of β-dialkyl dibenzothiophenes into reactive derivatives can also be achieved by modifying the active component with additives that increase its hydrogenating ability, for example, Ni, Cu or Pt group metals (Pt, Pd, Rh).

Thus, deep purification of diesel fuels from sulfur compounds can be provided by Co (Ni) -Mo (W) catalysts that have high catalytic activity in the reactions of transformation of sulfur compounds and are resistant to deactivation by sulfur compounds and hydrogen sulfide formed by the hydrogenolysis reaction. Along with activity and stability in the reactions of transformation of sulfur compounds, the catalysts must provide the diesel fuel required cetane number, the distribution of fractions by boiling point, density, aromatic and polyaromatic compounds. To solve these problems, many technological solutions are proposed, in particular, varying the type and structure of the carrier, the composition and amount of modifying additives, the composition and amount of the active component, the method of applying it to the carrier.

Patent (US 5686374, B01J 29/10, 11.11.97) describes a catalyst for hydrodesulfurization of hydrocarbons, including metal VI and / or VIII gr., Deposited on an inorganic refractory substance selected from the group consisting of alumina, a mixture of alumina and silica and / or magnesium oxide and / or calcium oxide and / or zeolite V and / or zinc oxide and, if necessary, a boron compound. The catalyst shows high activity in hydrodesulfurization reactions, has an increased service life, but has a high activity in cracking reactions.

Patent (US 6267874, B01J 21/12, 07/31/2001) describes a hydrotreatment catalyst that uses a mixed oxide aluminum-silicon carrier and an active component based on elements VIII (Co, Ni, Ru, Rh, Pd, It, Pt) and / or VI (Mo, W) groups of the periodic table. The composition of the carrier can be added oxides of titanium, zirconium, zeolite, clay. The main distinguishing feature of the carrier is the high dispersion of silicon oxide and the Brandsted acidity of at least 50 μmol / g. For impregnation, an ammonia solution with a pH of 9 is used, containing nickel nitrate, ammonium paramolybdate and citric acid. The catalyst is characterized by high resistance to deactivation by hydrogen sulfide, high activity in hydrodesulfurization and is significant in the process of deep hydrodesulfurization of high sulfur hydrocarbon fuels. The catalyst also shows high efficiency of hydrocracking, hydrodearomatization, hydroisomerization. However, the patent proposes an expensive technology for the synthesis of a silicon-aluminum oxide carrier, in particular the use of silicon and aluminum alkoxides as precursors, or elevated temperatures (40-90 ° C) for carrying out the coprecipitation and aging of gels in the case of using inorganic compounds of silicon and aluminum.

A known method of preparing Co (Ni) -Mo (W) catalysts for the desulfurization of petroleum fractions, including extrusion and heat treatment of a carrier based on oxides of aluminum, boron, titanium or zirconium, manganese (Al ₂ O ₃ : B ₂ O ₃ : TiO ₂ (ZrO ₂ ): MnO ₂ = 1: 0.005-0.053: 0.002-0.042: 0.0004-0.016), impregnated with an ammonia solution containing ammonium molybdenum (tungsten) acid and cobalt (nickel) nitrate, followed by heat treatment at 530 ° C (RU 2155637) , B01J 23/88, 09/10/2000). The main disadvantage of the catalyst is its lack of activity, which does not allow its use for the processes of deep hydrodesulfurization of crude oil. The catalyst containing, wt.%: 10-15 MoO ₃ and 4-6 CoO, provided hydrodesulfurization of the diesel fraction at the level of 93.3-93.5% with a sulfur content of 0.72 wt.%, A pressure of 3 MPa, 380 ° C volumetric feed rate of 2.5 h ^-1 and the frequency of circulation of hydrogen-containing gas 400 nm ³ / m ³ raw materials.

A known method of producing a catalyst by impregnating a pre-calcined carrier with a solution of ammonium heptamolybdate in the first stage and solutions of active metals in the second with intermediate and final heat treatments, including drying and calcining, in the second stage of the carrier impregnation, use a solution of cobalt nitrate and / or nickel nitrate and the intermediate heat treatment a temperature of 100-200 ° C, and the final heat treatment, including drying and calcination, is carried out respectively at a temperature of 100-200 ° C and 400-650 ° C (RU 2246987, B01J 37/02, 02.27.2005 )

In the patent (US 3840472, B01J 11/06, 8/10/1974) it is proposed to use molybdenum oxide and one of the metals of group VIII of the periodic system for the preparation of impregnating solutions, which is used in the form of carbonate, hydroxide, acetate, formate or oxide in solid form, dissolving them in phosphoric acid at the following concentrations of 0.3-2.5 mol / L P, 0.4-1.5 mol / L metal of group VIII and 1-3 mol / L Mo.

A similar technique for the preparation of the catalyst is proposed in a number of patents of the Union Oil Company of California: US 4,500,424, B01J 027/185, 02/19/1985; 4818743, B01J 027/185, 04/04/1989 and others. The catalyst is prepared by impregnation of gamma alumina, a solution containing molybdenum oxide, cobalt carbonate and phosphoric acid, in an amount necessary for introducing into the catalyst not less than, wt.%: 17-25 MoO ₃ , 1-6 CoO or NiO and 1-4 P, provided that the molar ratio P / MoO ₃ in the solution is higher than 0.1, preferably 0.2, and a pH in the range of 0-1.0. The patent also indicates that in the case of using ammonium paramolybdate as a precursor of a Group VIII metal, it is better to use cobalt or nickel nitrates. In the case of using molybdenum oxide as a precursor of a Group VIII metal, it is better to use cobalt or nickel carbonates.

A number of patents of the Union Oil Company of California (US 3755150; 3755196, 08/28/1973; 4846961, 07/11/1989) describe a catalyst that is prepared by impregnating silicon modified aluminum oxide with solutions of active metal salts (Mo, Ni, Co) with the introduction of in an impregnating solution of phosphorus compounds in the form of phosphoric acid. Increasing the stability of the impregnating solution containing ammonium paramolybdate and nickel (or cobalt) nitrate is achieved by introducing phosphoric acid into the solution to a mass ratio of P / MoO ₃ in the range of 0.1-0.25 and a pH in the range of 1-2. After calcination at 900 ° F, the hydrodesulfurization catalyst contains, wt.%: 5-40 MoO ₃ (predominantly 15-21.7), 1-10 NiO or CoO (predominantly 2.8-3.07) and 2.4-3 , 5 P deposited on silicon-modified Al ₂ O ₃ .

In the patent US 4392985, B01J 027/14, 07/12/1983 to obtain a stable impregnating solution containing ammonium paramolybdate and cobalt (or nickel) nitrate, it is proposed to introduce phosphoric acid into the solution to a mass ratio of P / MoO ₃ in the range of 0.05-0 , 16 and a pH below 1.2. The impregnating solution was stable, provided that it contained at least 17 wt.% MoO ₃ and a mass ratio of CoO / MoO ₃ in the range of 0.1-0.4.

The main disadvantage of the catalysts described in US patent 3755150, 3755196, 4392985, 4846961, is the high phosphorus content in the catalyst (2.4-3.5 wt.% P), which leads to insufficiently high activity in the hydrotreatment of diesel fractions in the processing of high sulfur oils and to a fairly high coke formation.

In the patent US 4879265, B01J 027/19, 07/07/1989 describes a method of preparing a highly active catalyst containing, wt.%: 17-27 MoO ₃ , 1-4 P and 0.5-5 NiO. The catalyst is prepared by impregnating a solution containing phosphate ion and citric acid, while maintaining the pH of the solution below 1.0 and the molar ratio of citric acid to metal of group VIB within 0.5-0.9 / 1, followed by drying and calcination at a temperature not lower than 750 ° F, mainly 1000 ° F. Ammonium paramolybdate and cobalt (or nickel) nitrate are mainly used for preparation, but it is noted that molybdenum oxide and cobalt (or nickel) oxide or carbonate can be used. When the catalyst is calcined, most of the citric acid decomposes, no more than 0.5 wt.% C. remains. The catalyst has high activity in the processes of hydrodesulfurization and hydrotreating.

The closest in technical essence to the claimed and achieved result is the catalyst described in the application US 2006/0054536, 03.16.2006. The prototype catalyst is prepared by impregnating an alumina carrier containing 1 wt.% Silicon dioxide or 5 wt.% Ultra-stabilized zeolite Y, an aqueous solution containing cobalt citrate, phosphoric acid (85% solution) and molybdophosphoric acid, provided that the pH of the solution varies within 0.52, followed by drying, first in a stream of nitrogen and then in a stream of air at 120 ° C for 12 hours. After calcination at 120 ° C, the catalyst contains, wt.%: 10-40 MoO ₃ (mainly 26 -29), 1-15 CoO and / or NiO (5.6-5.8), 1.5-8 P ₂ O ₃ (mainly 3.6-5, 5) and 2-14 C, deposited on the extrudates of γ-Al ₂ O ₃ , γ-Al ₂ O ₃ with silica (99/1) or γ-Al ₂ O ₃ with zeolite Y (95/5). The catalyst has a high hydrodesulfurization activity, providing a residual sulfur content of 8-10 ppm at a pressure of 4.9 MPa, a space velocity of 1.5 h ^-1 , a hydrogen / feed ratio of 200 m ³ / m ³ and a temperature of 350 ° C and sulfur content in raw materials 1.61 wt.%.

The main disadvantage of this catalyst is its high phosphorus content, which leads to rather rapid deactivation of the catalyst due to coking of hydrocarbon components of the oil fractions, especially when exposed to elevated temperatures, and to insufficiently high activity in the hydrotreatment of diesel fractions during the processing of high sulfur oils at low partial pressure of hydrogen.

The problem solved by the invention is the development of a composition and a method for preparing a highly efficient and stable catalyst containing molybdenum and cobalt and / or nickel compounds dispersed on the surface of a modified alumina support and intended for hydrodesulfurization of high-sulfur diesel fractions in existing hydrotreatment plants.

This is achieved by optimizing the texture of the catalyst containing molybdenum and cobalt and / or nickel compounds dispersed on the surface of the modified alumina support, and by optimizing the composition of the active complex.

Optimization of the texture of the support is achieved by the fact that, as the support, the catalyst contains calcined alumina modified at the stage of extrudate preparation with the C- or Na-form of montmorillonite. The introduction of a montmorillonite sol into a molding material based on aluminum hydroxide obtained by one of the deposition methods (continuous or batch) or by hydrolysis of aluminum isopropylate allows for a high specific surface area of the support (at least 200 m ² / g), developed porous structure (at least 0.6 cm ³ / g) with a narrow pore size distribution (mainly with pores of 80-140 Å), optimal acidity and high mechanical strength.

The introduction of montmorillonite has a positive effect on the stability of the catalyst to deactivation by hydrogen sulfide formed by the C-S hydrogenolysis of the bond of sulfuric aromatic compounds, both by increasing the acidity of the carrier and due to the presence of Ca and Mg cations in montmorillonite. In addition, the introduction of montmorillonite into the carrier enhances the hydrogenating ability of the hydrodesulfurization catalyst and, therefore, facilitates the conversion of β-dialkyl dibenzothiophenes to reactive derivatives along the hydrogenation routes of one of the benzene rings.

Optimization of the composition of the active complex and its uniform application is achieved by the fact that the content of molybdenum compounds is in the range of 14-29 wt.% MoO ₃ , mainly 16-21 wt.%, And the ratio of Mo / Co and / or Mo / Ni varies in the range of 1 , 3-2.6, which is sufficient to ensure high activity in hydrodesulfurization of diesel fractions. With the indicated content of MoO ₃ and the ratio of Mo / Co and / or Mo / Ni, the optimal content of the so-called “CoMoS-II” centers is formed, namely, sections of the layered structure of MoS ₂ doped with cobalt or nickel cations. To increase the uniformity of deposition of the active complex, impregnating solutions containing molybdenum oxide and cobalt carbonate stabilized with phosphoric and citric acid additives are used. Moreover, the pH of the impregnating solutions in the range of 1-2.5 and the atomic ratio of P / Mo in the range of 0.08-0.1 is sufficient to ensure the stability of the solutions for 3-4 months. The introduction of an additive of citric acid into the impregnation solution at a molar ratio of CoCO ₃ / citric acid equal to 3/2 eliminates the interaction of cobalt compounds with aluminum oxide at the stages of impregnation, which leads to the formation of crystallized phases Co ₃ O ₄ and CoAl ₂ O ₄ upon calcination . Slow drying of the impregnated carrier in an inert gas stream or in an air atmosphere eliminates crystallization of the active complex, and calcination in an air stream at temperatures up to 240 ° C eliminates the destruction of the active complex. The above methods used to prepare the catalyst ensure the formation of a large number of CoMo8-II centers and increase the activity of the catalyst at moderate hydrodesulfurization temperatures of diesel fractions.

In addition, the decrease in the content of phosphate ion in the catalyst to a ratio of 0.08-0.1 allows for its resistance to deactivation as a result of the deposition of hydrocarbon components of diesel fuel on the surface of the catalyst. At the indicated P / Mo ratio, surface modification of the alumina support by phosphate ions is excluded, which excludes adsorption of hydrocarbons on these centers and deactivation due to coking.

The carrier, and hence the catalyst, is predominantly made in the form of extrudates — cylinders or trefoils, with a diameter of 1.0-1.5 mm and a length of 3-5 mm. The use of extrudates in the form of a “trefoil” also allows increasing the efficiency of hydrodesulfurization of oil fractions.

The above method of preparing the proposed catalyst allows you to increase the activity of Co-Mo catalyst for hydrodesulfurization of diesel fractions at temperatures of 320-350 ° C, a pressure of 3.5 MPa and a multiplicity of hydrogen-containing gas circulation of 300 m ³ / m ^{3 of} raw materials and the catalyst resistance to deactivation in the presence of organic sulfur-containing compounds at elevated temperatures, and therefore, to use the catalyst in the processes of hydrodesulfurization of diesel fractions on existing equipment. The described catalyst variant is preferred for hydrodesulfurization of diesel fractions.

The process of hydrotreating diesel fractions in existing industrial plants is carried out at a temperature of 340-400 ° C, at a pressure of 3-3.5 MPa and 5.2-5.5 MPa in the case of Co-Mo and Ni-Mo catalysts, respectively, and the multiplicity of hydrogen-containing gas circulation 250-350 m ³ / m ^{3 of} raw materials. The concentration of sulfur compounds in diesel fractions is usually ~ 1-1.5 wt.% In terms of elemental sulfur. In accordance with this, the conditions for testing the catalysts were chosen.

The catalysts were tested in the form of a fraction of 0.25-0.5 mm in size, which was prepared by crushing and dispersing the original extrudates. A 2.0 g sample of catalyst was placed in a vertical stainless steel flow reactor having an internal diameter of 8 mm, while the height of the catalyst layer was 50 ± 10 mm. A layer of silicon carbide (particles 1-2 mm) was placed above the catalyst layer for uniform mixing and heating of the feedstock, which was separated from the catalyst layer with a fiberglass swab. A layer of quartz (particles of 1-2 mm) was placed below the catalyst layer to fill the free volume of the reactor, which was also separated from the catalyst layer by a fiberglass swab.

The catalysts were sulfidized at atmospheric pressure in a stream of hydrogen sulfide, which began to be fed at room temperature at a rate of 1 l / h. The reactor was heated from room temperature to 400 ° C for 30 minutes and then sulfidation was continued for 2 hours. Then, using shut-off valves, the reactor was simultaneously cut off from the hydrogen sulfide supply and discharge lines and cooled to room temperature.

As the feedstock, straight-run diesel fuel is used having the following characteristics:

Density at 20 ° С 844 kg / m ³

Cetane number 53.5 ± 0.5

The pour point is about - 10 ° C

Sulfur Content 1.06% S (10,600 ppm)

Flash point (in a closed crucible) 66.9 ° С

Fractional composition of 50% of the volume is distilled at 292 ° С

96% of the volume is distilled at 366 ° C.

The sulfidated catalyst reactor was placed in an electric heated thermostat, filled with hydrogen to a pressure of 3.5 MPa at room temperature, after which the supply of diesel fuel was started, providing a mass fuel consumption of 2 h ^-1 and adjusting the hydrogen flow to a volume ratio of hydrogen / diesel fuel, equal to 300. At that moment, when the flow rates of the reagents stabilized, heating up of the reactor from room temperature to 340 ° C began, which was carried out for 35-40 minutes. Next, the process was carried out at a temperature of 340 ° C and a pressure of 3.5 MPa.

At the outlet of the reactor, the products passed through a stainless steel capillary with an inner diameter of 2 mm, in which they were cooled to 60-70 ° С, after which they entered the pressure relief unit to atmospheric pressure. Further, the products were cooled in a refrigerator-separator equipped with a water jacket and divided into gas and liquid components. The ablation of liquid by gas did not exceed 1 wt.%. The products accumulated during the first 3 hours after the start of the temperature rise in the reactor were discarded without any analysis, then every 2 hours the mass yield of the obtained diesel fuel and its sulfur content were determined.

The activity of the catalyst was judged by the content of residual sulfur in oil products. The mass content of sulfur in liquid petroleum products was determined without first removing the hydrogen sulfide dissolved in them. To determine the sulfur content, a HORIBA SLFA-20 X-ray fluorescence analyzer was used, which made it possible to operate in the concentration range S from 20 ppm to 5 wt.% With an accuracy of 5 ppm. Special experiments to remove hydrogen sulfide using a 10% aqueous NaOH solution (mixed with a 1 to 1 sample) showed that the content of hydrogen sulfide dissolved in petroleum products can range from 20-80 ppm.

To assess the deactivation of catalysts due to coking by hydrocarbon components and sulfur-containing compounds of diesel fractions, the catalysts were exposed to elevated temperatures of 370 ° C for 6-9 hours (to accelerate decontamination processes), after which the activity of the catalysts was measured at a temperature of 340 ° C, a pressure of 3.5 MPa, and hydrogen / feed circulation ratio 300.

In a number of experiments, the activity of the catalysts was determined at a temperature of 350 ° С, a pressure of 3.5 MPa, a liquid fuel consumption of 2 h ^-1 and a hydrogen / feed ratio of 500, and the conditions for the conditioning are similar to those described above.

The invention is illustrated by the following examples.

Example 1 (table 1)

To 80 g of aluminum hydroxide obtained by periodic precipitation and containing 95% pseudoboehmite with a moisture content of 76%, 8.27 g of Ca-montmorillonite dispersed in water and having a moisture content of 59% and 0.2 ml of 7% nitric acid are added, stirred for 20 min on a Z-shaped mixer. Extrudates are formed from the resulting mass. The extrudates are calcined in an air stream at 550 ° C for 4 hours. After calcination, the extrudates contain γ-Al ₂ O ₃ and Ca-montmorillonite in a 85/15 mass ratio, have a specific surface area of 276 m ² / g, pore volume 0.85 cm ³ / g and an average pore radius of 106 Å.

To prepare an impregnating solution, 6.0 ml of distilled water is added to 6.0 g of cobalt carbonate and heated to a temperature of 80 ° C. Then, while stirring, 7.14 g of citric acid monohydrate are added in portions, with an intense evolution of CO ₂ . After waiting for the complete dissolution of the precipitate, add 14.7 g of molybdenum oxide, MoO ₃ , and 1.18 g of phosphoric acid (85% solution). Continue to mix the solution at a temperature of 80 ° C until complete dissolution. After complete dissolution, the volume of the solution is 50 ml. The solution contains 22.4 wt.% MoO ₃ , is characterized by a molar ratio of Mo / Co 2 and P / Mo of 0.1, has a pH of 2.45.

25.5 ml of the impregnation solution are added to 30 g of calcined extrudates, and they are left to stand for 15 minutes. The impregnated extrudates are dried in a stream of nitrogen and then in a muffle in an atmosphere of air at 150 ° C for 10 hours

The content of molybdenum oxide in the catalyst is 19.0 wt.% (Hereinafter, based on MoO ₃ ), cobalt oxide 4.9 wt.% (Hereinafter, based on CoO) and phosphorus 0.4 wt.% (In based on P).

The catalyst after calcination at 150 ° C has a specific surface area (S _beats ) of 156 m ² / g, a pore volume (V _Σ ) of 0.33 cm ³ / g and an average pore radius (D _cp ) of 95 Å.

A 0.2-0.5 mm fraction is prepared from the extrudates of the catalyst, 2 g of the fraction are loaded into the reactor and subjected to sulfidation in a stream of hydrogen sulfide at 400 ° C for 2 hours.

Determine the yield of liquid petroleum products and the sulfur content in them, which is provided by the sulfidized catalyst when straight-run diesel fuel is supplied with a sulfur content of 1.06 wt.%, And the following process conditions: temperature 340 ° C, pressure 3.5 MPa, mass diesel consumption of 2 h ^-1 and a volume ratio of hydrogen / diesel fuel of 300.

Under the specified conditions of the diesel hydrotreatment process, the catalyst provides a decrease in the sulfur content in liquid petroleum products to a level of 150-180 ppm and a yield of liquid petroleum products at a level of 96-97%.

After 24 hours, the temperature in the reactor was raised to 370 ° C and the sulfur content in liquid petroleum products was determined, while the sulfur content in liquid petroleum products was reduced to a level of 70-80 ppm.

After 9 hours, reduce the temperature in the reactor to 340 ° C and determine the sulfur content in liquid petroleum products. The catalyst provides a sulfur content in liquid petroleum products at a level of 230-250 ppm.

Example 2 (table 1)

Similar to example 1, only for the preparation of an impregnating solution, 9.04 g of cobalt carbonate, 10.63 g of citric acid monohydrate, 15.3 g of molybdenum oxide and 1.23 g of an 85% phosphoric acid solution are used. The resulting solution contains 22.4 wt.% MoO ₃ , has a molar ratio of Mo / Co equal to 1.4, and P / Mo of 0.1, and a pH of 1.9.

After impregnation of 30 g of the support from Example 1 containing alumina and Ca-montmorillonite in a weight ratio of 85/15, 25.5 ml of the solution, the catalyst is dried and calcined under the conditions of Example 1. The texture characteristics of the catalyst and the composition of the active component are shown in Table 1 .

Under the testing conditions of Example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at 210-230 ppm at 340 ° C.

Example 3 (table 1)

Similar to example 1, only for the preparation of an impregnating solution, 5.03 g of cobalt carbonate, 5.92 g of citric acid monohydrate, 14.7 g of molybdenum oxide and 1.17 g of an 85% phosphoric acid solution are used. The resulting solution contains 22.4 wt.% MoO ₃ , has a molar ratio of Mo / Co equal to 2.4, and P / Mo of 0.1, and a pH of 1.7.

After impregnation of 30 g of the support from Example 1 containing alumina and Ca-montmorillonite in a weight ratio of 85/15, 25.5 ml of the solution, the catalyst is dried and calcined under the conditions of Example 1. The texture characteristics and composition of the catalyst are shown in Table 1.

Under the test conditions of example 1, the catalyst provides 97% yield of liquid petroleum products and their sulfur content at a level of 220-250 ppm at 340 ° C.

Example 4 (table 1)

Similar to example 1, only for the preparation of the impregnating solution, 4.65 g of cobalt carbonate, 5.47 g of citric acid monohydrate, 14.66 g of molybdenum oxide and 1.18 g of 85% phosphoric acid solution are used. The solution contains 22.4 wt.% MoO ₃ , has a molar ratio of Mo / Co of 2.6 and P / Mo of 0.1 and a pH of 1.7.

After impregnation of 30 g of the support from Example 1 containing alumina and Ca-montmorillonite in a weight ratio of 85/15, 25.5 ml of the solution, the catalyst is dried and calcined under the conditions of Example 1. The texture characteristics and composition of the catalyst are shown in Table 1.

Under the test conditions of Example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at 370 ppm at 340 ° C.

Example 5 (table 1)

Similar to example 1, only for the preparation of an impregnating solution, 6.17 g of cobalt carbonate, 7.26 g of citric acid monohydrate, 17.94 g of molybdenum oxide and 1.43 g of an 85% phosphoric acid solution are used. The solution contains 25.4 wt.% MoO ₃ , has a molar ratio of Mo / Co of 2.4 and P / Mo of 0.1, and a pH of 1.8.

After impregnation of 30 g of the support from Example 1 containing alumina and Ca-montmorillonite in a weight ratio of 85/15, 25.5 ml of the solution, the catalyst is dried and calcined under the conditions of Example 1. The texture characteristics and composition of the catalyst are shown in Table 1.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 250-280 ppm at 340 ° C.

Example 6 table 1)

3.67 g of Ca-montmorillonite dispersed in water and having a moisture content of 59% and 0.2 ml of 7% nitric acid are added to 80 g of aluminum hydroxide obtained by periodic precipitation and containing 95% pseudoboehmite with a moisture content of 75% mix and shape the extrudates. The extrudates are calcined in an air stream at 550 ° C for 4 hours. After calcination, the extrudates contain γ-Al ₂ O ₃ and Ca-montmorillonite in a weight ratio of 93/7, have a specific surface area of 238 m ² / g, pore volume 0.85 cm ³ / g and an average pore radius of 109 Å.

The solution is prepared analogously to example 1, only for the preparation of the solution take 7.12 g of cobalt carbonate, 8.37 g of citric acid monohydrate, 18.11 g of molybdenum oxide and 1.45 g of an 85% phosphoric acid solution. The resulting solution contains 25.4 wt.% MoO ₃ , has a molar ratio of Mo / Co equal to 2.1, and P / Mo of 0.1, and a pH of 1.5.

25.5 ml of the solution is added to 30 g of the support, it is left to stand for 15 minutes, and then the impregnated support is dried at room temperature and heat treated at 150 ° C for 8 hours under a stream of nitrogen.

The texture characteristics and composition of the catalyst are given in table 1.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 280-300 ppm at 340 ° C.

Example 7 (table 1)

To 80 g of aluminum hydroxide obtained by periodic precipitation and containing 95% pseudoboehmite with a moisture content of 75%, 2.56 g of Ca-montmorillonite dispersed in water and having a moisture content of 59% and 0.2 ml of 7% nitric acid are added, mix and mold into extrudates. The extrudates are calcined in a stream of air at 550 ° C for 4 hours. After calcining, the extrudates contain γ-Al ₂ O ₃ and Ca-montmorillonite in a weight ratio of 95/5, have a specific surface area of 245 m ² / g, pore volume 0.85 cm ³ / g and an average pore radius of 115 Å.

An impregnating solution is prepared analogously to example 6.

25.5 ml of the solution is added to 30 g of the support, it is left to stand for 15 minutes, and then the impregnated support is dried and heat-treated at 150 ° C for 8 hours under a stream of nitrogen. The texture characteristics and composition of the catalyst are given in table 1.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 280-300 ppm at 340 ° C.

Example 8 (table 1)

To 80 g of aluminum hydroxide obtained by periodic precipitation and containing 95% pseudoboehmite with a moisture content of 70%, 9.52 g of Na-montmorillonite dispersed in water and having a moisture content of 72% was added, stirred for 20 minutes and formed into extrudates. The extrudates are calcined in an air stream at 550 ° C for 4 hours. After calcination, the extrudates contain γ-Al ₂ O ₃ and Na-montmorillonite in a mass ratio of 90/10, have a specific surface area of 229 m ² / g, pore volume 0.7 cm ³ / g and an average pore radius of 75 Å.

An impregnating solution is prepared analogously to example 6.

To 30 g of the support, 21 ml of the solution are added, stand for 15 minutes, and then the impregnated support is dried and heat-treated at 150 ° C for 8 hours under a stream of nitrogen.

The texture characteristics and composition of the catalyst are given in table 1.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 240-270 ppm at 340 ° C.

Example 9 (table 1)

The method of preparation of the carrier and its composition are similar to example 1.

To prepare the impregnation solution, 5.09 g of cobalt carbonate, 2.19 g of nickel carbonate, 8.37 g of citric acid monohydrate, 18.11 molybdenum oxide and 1.45 g of an 85% phosphoric acid solution are used. The solution contains 25.4 wt.% MoO ₃ , has a molar ratio (Mo / Co + Mo / Ni) of 2.1, and P / Mo of 0.1, pH 1.5.

To 30 g of the carrier from example 1 (with a ratio of Al ₂ O ₃ to Ca-montmorillonite equal to 85/15 and a pore volume of 0.85 cm ³ / g), 25.5 ml of the solution was added, held for 15 minutes and then the impregnated carrier was dried and subjected to heat treatment at 150 ° C for 8 hours in a stream of nitrogen.

The texture characteristics and composition of the catalyst are given in table 1.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at the level of 250-290 ppm at 340 ° C.

Example 10 (table 2)

The method of preparation of the carrier, the impregnation solution and the catalyst is similar to those of example 5.

A 0.2-0.5 mm fraction is prepared from the extrudates of the catalyst, 2 g of the fraction are loaded into the reactor and subjected to sulfidation in a stream of hydrogen sulfide at 400 ° C for 2 hours. Next, a stream of hydrogen and straight-run diesel fuel with sulfur content are fed to the sulfidized catalyst 1.06 wt.% And determine the yield of liquid petroleum products and their sulfur content under the following process conditions: temperature 350 ° C, pressure 3.5 MPa, mass flow rate of diesel fuel 2 h ^-1 and the volume ratio of hydrogen / diesel fuel 500.

The catalyst provides a yield of liquid petroleum products at the level of 96-99% and hydrotreatment of diesel fuel to a sulfur content of 20-32 ppm in it.

Example 11 (table 2)

The method of preparation of the carrier, the impregnation solution and the catalyst is similar to those of example 8.

The sulfidation and testing conditions are similar to those of example 10 (temperature 350 ° C and a volume ratio of hydrogen / diesel fuel of 500). Under these conditions, the catalyst provides a yield of liquid petroleum products at the level of 97% and hydrotreatment of diesel fuel to a sulfur content of 50-75 ppm.

Example 12 (comparative prototype, table 3)

To prepare an impregnating solution, 11.64 g of cobalt citrate and 1.82 g of phosphoric acid (85% solution) are added to 42 g of distilled water, heated to 80 ° C and stirred for 10 minutes. Then add 17.74 g of phosphoromolybdic acid and stirred at the same temperature until complete dissolution. The resulting solution has a pH of 0.52, contains 24 wt.% MoO ₃ , a molar ratio of Mo / Co of 2.4 and P / Mo of 0.2.

The carrier used is extrudates obtained by extrusion of a paste based on peptized aluminum hydroxide of continuous deposition, with subsequent stages of drying and calcination in an air stream at 550 ° C for 4 hours. Extrudates dimensions: diameter 1.3-1.4 mm, length 4 -5.2 mm. The extrudates are characterized by a specific surface area of 275 m ² / g, a pore volume of 0.82 cm ³ / g and an average pore radius of 119 Å, determined from nitrogen adsorption isotherms. The pore size of 70-130 Å accounts for 65% of the total pore volume.

To 30 g of calcined extrudates add 27 ml of impregnation solution and incubated for 15 minutes The impregnated extrudates are dried at room temperature in a stream of nitrogen and subjected to heat treatment in a stream of nitrogen at 150 ° C for 10 hours

The catalyst contains, wt.%: 21.3 MoO ₃ , 4.6 CoO and 1.2 R.

The catalyst after calcination at 150 ° C has a specific surface area (S _beats ) of 150 m ² / g, a pore volume (V _Σ ) of 0.31 cm / g and an average pore radius (D _cf ) of 85 Å.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 380-400 ppm at 340 ° C.

Example 13 (comparative 1, table 3)

An impregnating solution is prepared analogously to example 1, but to prepare the solution, 9.27 g of cobalt carbonate, 10.21 g of citric acid monohydrate, 26.95 g of molybdenum oxide and 2.14 g of an 85% phosphoric acid solution are taken. The resulting solution contains 34 wt.% MoO ₃ , has a Mo / Co molar ratio of 2.4, and P / Mo of 0.1, and has a pH of 2.4.

After impregnating 30 g of the support from Example 1 containing alumina and Ca-montmorillonite in a weight ratio of 85/15, 25.5 ml of the solution, the catalyst is dried and calcined under the conditions of Example 1.

The texture characteristics and composition of the catalyst are given in table.3.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at 360-380 ppm at 340 ° C.

Example 14 (comparative 2, table 3)

Similar to example 1, but to prepare the impregnating solution, 7.62 g of cobalt carbonate, 8.96 g of citric acid monohydrate, 22.6 g of molybdenum oxide and 5.77 g of phosphoric acid (85% solution) are used. The solution contains 25.4 wt.% MoO ₃ , has a molar ratio of Mo / Co of 2.4 and P / Mo of 0.38, and a pH of 0.75.

The texture characteristics and composition of the catalyst are given in table.3.

Under the testing conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 380-400 ppm at 340 ° C.

Example 15 (comparative 3, table 2)

The method of preparation of the carrier, the composition of the impregnating solution and the catalyst are similar to example 14.

Under the test conditions of example 10 (at 350 ° C and a volume ratio of hydrogen / diesel fuel of 500), the catalyst provides 95% yield of liquid petroleum products and their sulfur content at the level of 85-90 ppm.

Example 16 (comparative 4, table 2)

Similar to example 1, but to prepare an impregnating solution, 5.1 g of cobalt carbonate, 6.0 g of citric acid monohydrate, 18.53 g of molybdenum oxide and 7.03 g of phosphoric acid (85% solution) are used. The solution contains 25.4 wt.% MoO ₃ , has a molar ratio of Mo / Co 3 and P / Mo of 0.4, and a pH of 0.5.

The texture characteristics and composition of the catalyst are given in table.2.

Under the test conditions of example 10 (at 350 ° C and a volume ratio of hydrogen / diesel fuel of 500), the catalyst provides 97% yield of liquid petroleum products and their sulfur content at a level of 120-140 ppm.

Example 17 (comparative 5, table 3)

Similar to example 1, but to prepare an impregnating solution, 9.57 g of cobalt carbonate, 11.26 g of citric acid monohydrate, 27.82 g of molybdenum oxide and 5.28 g of phosphoric acid (85% solution) are used. The solution after dissolution contains 34 wt.% MoO ₃ , has a molar ratio of Mo / Co of 2.4 and P / Mo of 0.24, pH 0.85.

The texture characteristics and composition of the catalyst are given in table. 3.

Under the test conditions of example 1, the catalyst provides 96% yield of liquid petroleum products and their sulfur content at a level of 380-420 ppm at 340 ° C.

Example 18 (comparative 6, table 2)

To prepare an impregnating solution, 11.75 g of ammonium paramolybdate, (NH ₄ ) ₆ · Mo ₇ O ₂₄ · 4H ₂ O, is dissolved in 12 ml of distilled water mixed with 4.25 g of 85% phosphoric acid (85% solution), heated to 80 ° C. After complete dissolution, add 3.5 g of citric acid monohydrate and 6.5 g of cobalt nitrate, Co (NO ₃ ) ₂ · 6H ₂ O. After dissolution, a solution of 22 ml is obtained. The solution contains 22.4 wt.% MoO ₃ , has a molar ratio of Mo / Co 3 and P / Mo of 0.5, and a pH of 0.7.

To prepare the catalyst take 30 g of calcined extrudates from example 1 containing Al ₂ About ₃ and Ca-montmorillonite in a mass ratio of 85/15. 22.5 ml of the solution is added to the extrudate and the impregnation is carried out at 25 ° C for 15 minutes.

The impregnated extrudates are dried in a stream of nitrogen and then calcined in a muffle in an atmosphere of air at 200 ° C for 2 hours.

 The texture characteristics and composition of the catalyst are given in table.2.

Under the test conditions of example 10 (at 350 ° C and a volume ratio of hydrogen / diesel fuel of 500), the catalyst provides 95% yield of liquid petroleum products and their sulfur content at a level of 200-250 ppm.

Example 19 (comparative 7, table 2)

The composition and sequence of preparation of the impregnating solution are similar to those of example 5, the difference is that extrudates from aluminum oxide are used to prepare the catalyst.

For the preparation of alumina extrudates, an industrial aluminum hydroxide powder obtained by hydrolysis of aluminum isopropylate and having a pseudoboehmite structure is used. To obtain a molding paste, to 39 g of a sol of aluminum hydroxide with a moisture content of 28% add 3 ml of concentrated nitric acid (with a density of 1.41 g / cm ³ ) mixed with 49 ml of distilled water, and mix in a Z-shaped mixer. Next, 4.94 g of γ-Al ₂ O ₃ powder is added to the obtained sol, the mass is mixed for 20 minutes and shaped as cuttings. Drying and calcining extrudates in an air stream at 550 ° C for 4 hours. The obtained extrudates have a specific surface area of 235 m ² / g, a pore volume of 0.51 cm ³ / g and an average pore radius of 85 Å, determined from nitrogen adsorption isotherms. Pore size 70-130 Å accounts for 50% of the total pore volume.

For impregnation, 30 g of extrudates and 21 ml of impregnation solution are taken. Drying and heat treatment conditions are similar to the conditions of example 1.

The texture characteristics and composition of the catalyst are given in table.2.

Under the test conditions of example 10 (at 350 ° C and a volume ratio of hydrogen / diesel fuel of 500), the catalyst provides 98% yield of liquid petroleum products and their sulfur content at a level of 50-65 ppm.

It can be seen that the inventive compositions of Co (Ni) -Mo catalysts containing compounds of molybdenum, cobalt (nickel) and phosphorus in a molar ratio of Mo / (Co + Ni) of 1.3-2.6 and P / Mo of 0.08-0 , 1, dispersed on a porous alumina carrier with a modifying additive of montmorillonite (examples 1-3 and 4-9), have hydrodesulfurization activity and resistance to deactivation higher than samples with a P / Mo ratio of 0.2 (examples 12, 14). Within the indicated limits of the molar ratios of Mo / Co and / or Mo / Ni and P / Mo, the content of the active component is predominantly in the amount of 16-21 wt.% MoO ₃ and 4-6 wt.% CoO and / or NiO is sufficient for use on existing hydrotreatment of oil fractions, providing at a temperature of 340 ° C, a pressure of 3.5 MPa and a hydrogen / fuel ratio of 300 hydrotreating diesel fuels from sulfur compounds to a sulfur content of not higher than 300 ppm. Under similar hydrodesulfurization conditions, samples characterized by a high phosphorus content (P / Mo≥0.2, examples 12, 14) ensure that sulfur is removed from diesel fuel only to a level of 380-420 ppm.

It is seen that at a close content of modibdenum oxide (for example, 19 wt.%), The increase in the molar ratio of Mo / Co and / or Mo / Ni in the catalyst is higher than 2.4, for example, to 2.6 (example 4) or 3.0 (example 16), leads to a decrease in the hydrodesulfurization activity of the catalyst. So, Co-Mo catalysts with a content of 19 wt.% MoO ₃ and a Mo / Co ratio of 2.0 (Example 1) and 2.6 (Example 4) provide hydrodesulfurization of diesel fuel to a sulfur content of 150-180 and 370 ppm, respectively, at a temperature of 340 ° С, a pressure of 3.5 MPa, and a hydrogen / fuel ratio of 300. A tendency toward a decrease in the hydrodesulfurization activity of catalysts characterized by a molar ratio of Mo / Co above 2.4 is also observed when carrying out the hydrodesulfurization process at a temperature of 350 ° With a higher hydrogen / fuel volume ratio of 500 (approx. ep 16).

A tendency toward a decrease in the hydrodesulfurization activity of Co-Mo catalysts is also observed with a decrease in the molar ratio of Mo / Co and / or Mo / Ni below 1.4, however, in this case, the decrease in activity is not so strong. So, Co-Mo catalysts with a content of 19 wt.% MoO ₃ and a Mo / Co ratio of 2.0 (example 1) and 1.4 (example 2) at a temperature of 340 ° C provide hydrodesulfurization of diesel fuel to sulfur content on levels of 150-180 and 210-230 ppm, respectively.

The tendency to a decrease in catalytic activity in the process of hydrodesulfurization of diesel fuels is observed with an increase in the content of molybdenum oxide to 29 wt.% (Example 13). However, this trend is less pronounced with the introduction of cobalt and phosphorus in the claimed limits of the molar ratios of P / Mo and Mo / Co, which can be seen from a comparison of the activity of the samples from example 13 and 17, providing hydrodesulfurization of diesel fractions to the level of 360-380 ppm and 380-420 ppm respectively.

A comparison of the activity of samples 16 and 18, having a similar chemical composition, shows that the use of molybdenum oxide and cobalt carbon dioxide as the precursors of the active compound (Example 16) is preferable because it provides the catalyst with greater hydrodesulfurization activity compared to a catalyst prepared from an impregnating solution containing ammonium paramolybdate and cobalt nitrate (example 18). At a temperature of 350 ° C and a hydrogen / fuel ratio of 500, samples 16 and 18 provide a sulfur content in diesel fuel of 120-140 and 200-250 ppm, respectively.

The decrease in the content of phosphate ion in the catalyst from a P / Mo ratio of 0.2 to 0.08-0.1 makes it possible to increase the catalyst's resistance to deactivation, as indicated by experiments on the effect of elevated temperatures of the hydrotreatment process of diesel fractions. So, after exposure to a temperature of 370 ° C for 7-9 hours, samples with a similar content of molybdenum oxide, characterized by a molar ratio of P / Mo in the claimed range of 0.08-0.1 (example 5) and with a ratio of P / Mo≥0, 2 (example 14), provide hydrodesulphurization of diesel fuels to the level of 330-350 and 440-450 ppm, respectively.

A comparison of the activity of samples No. 5 and 19, having a similar composition of the active component, shows that the addition of montmorillonite to alumina has a positive effect on hydrodesulfurization activity. Samples No. 5 and 19, prepared on alumina supports with and without montmorillonite, provide hydrotreating of diesel fuel to the levels of 19-32 and 50-65 ppm, respectively, at a temperature of 350 ° C and a hydrogen-containing gas circulation rate of 500. Introduction of the additive to the alumina carrier montmorillonite provides the carrier with a developed porous structure (at least 0.6 cm ³ / g) with a narrow pore size distribution (mainly with pores of 80-140 Å), optimal acidity and high mechanical strength. In addition, the presence of montmorillonite in the composition of the catalyst has a positive effect on the stability of the catalyst to deactivation by hydrogen sulfide, which is formed by the hydrogenolysis of the CS bond of sulfuric aromatic compounds, both by increasing the acidity of the support and by the presence of Ca and Mg cations in montmorillonite.

The inventive composition of the catalysts provides an increase in the hydrodesulfurization activity of Co (Ni) -Mo catalyst at moderate temperatures (320-340 ° C) and pressure (up to 3.5 MPa) of their use with a simultaneous increase in the stability of catalysts to deactivation by sulfur organic compounds at elevated temperatures (360 -370 ° С) and hydrogen sulfide deactivation formed by the hydrogenolysis of sulfur organic compounds.

Table 1
The chemical composition and texture characteristics of the catalysts of the proposed composition and their catalytic properties determined during the hydrotreatment of straight-run diesel fuel at a temperature of 340 ° C, a pressure of 3.5 MPa, a fuel consumption of 2 h ^-1 and a volume ratio of hydrogen / diesel fuel of 300. No. Chemical composition, wt.% Texture characteristics Catalytic performance CoO wt.% NiO wt.% MoO ₃ wt.% P wt.% Mo / Co (Ni), molar P / Mo, molar S _beats , m ² / g V _Σ , cm ³ / g D _Wed , Å D _cp ± 15 Å,% Sulfur content, ppm, X _S ,% Y% 340 ° 370 ° 340 ° one. 4.9 - 19.0 0.4 2.0 0.10 156 0.33 95 65 150-180 70-80 230-250 98.6 98.3 96-97 2. 6.9 - 19.0 0.33 1.43 0.08 144 0.31 90 65 210-230 35-55 295-310 98.0-97.8 96 3. 3.8 - 17.5 0.41 2.40 0.11 139 0.33 95 65 220-250 70-90 295-310 97.9-97.6 97 four. 3.6 - 18.0 0.35 2.60 0.09 158 0.33 93 63 370 60 400 96.5 97 5. 4.4 - 21.1 0.45 2.40 0.10 120 0.30 87 60 250-280 45-55 330-350 97.697.4 96 6. 5.4 - 21.6 0.37 2.08 0.08 120 0.30 96 60 280-300 50-60 370-390 97.4-97.1 96 7. 5.4 - 21.6 0.38 2.08 0.08 115 0.31 98 62 280-300 40-50 360-370 97.4-97.1 96 8. 4.3 - 17.2 0.38 2.08 0.10 138 0.29 75 54 240-270 40-50 290-330 97.7-97.4 96 9. 3.9 1.2 20.3 0.41 2.07 0.09 148 0.34 90 58 250-290 70-90 330-340 97.7-97.3 96 Textural characteristics obtained from nitrogen adsorption isotherms: S _beats , m ² / g - BET specific surface area; V _Σ , cm ³ / g - pore volume, from nitrogen desorption isotherms; D _cp , Å — average pore radius; D _cp ± 15 Å,% - fraction of pores with a size of D _cp ± 15 Å; Catalytic characteristics: sulfur content in liquid petroleum products, ppm, at specified process temperatures; X _S ,% - degree of hydrodesulfurization at 340 ° C; Y,% - yield of liquid petroleum products at 340 ° C;

table 2
The chemical composition and texture characteristics of the catalysts and their catalytic properties determined during the hydrotreatment of straight-run diesel fuel at a temperature of 350 ° C, a pressure of 3.5 MPa, a fuel consumption of 2 h ^-1 and a volume ratio of hydrogen / diesel fuel of 500. No. Chemical composition, wt.% Texture characteristics Catalytic performance at 350 ° C CoO, wt.% NiO
wt.% MoO ₃ ,
wt.% P, wt.% Mo / Co (Ni), molar P / Mo, molar S _beats , m ² / g V _Σ , cm ³ / g D _Wed , Å D _cf ± 15 Å,% Sulfur content, ppm, X _S ,% Y% 10 4.4 - 21.1 0.45 2.40 0.10 120 0.30 87 60 19-32 99.7 96-99 eleven 4.3 17.2 0.38 2.08 0.10 138 0.29 75 54 50-75 99.3 97 fifteen 4.73 - 20.8 1.39 2.29 0.31 110 0.24 96 45 85-90 99.1 95 16 3.28 - 19.2 1.59 3.00 0.38 105 0.24 90 fifty 120-140 98.7 97 eighteen 2.87 - 16.2 1.65 2.94 0.47 101 0.23 92 40 200-250 97.6 95 19 3.6 - 17.4 0.37 2.40 0.10 137 0.24 67 60 50-65 99.4 98 Textural characteristics obtained from nitrogen adsorption isotherms: S _beats , m ² / g - BET specific surface area; V _Σ , cm ³ / g - pore volume, from nitrogen desorption isotherms; D _cp , Å — average pore radius; D _cp ± 15 Å,% - fraction of pores with a size of D _cp ± 15 Å; Catalytic characteristics: sulfur content in liquid petroleum products, ppm, at a temperature of 350 ° C; X _S ,% - degree of hydrodesulfurization at 350 ° C; Y,% - yield of liquid petroleum products at 350 ° C;

Table 3
The chemical composition and texture characteristics of the comparative samples and their catalytic properties determined during hydrotreatment of straight-run diesel fuel at a temperature of 340 ° C, a pressure of 3.5 MPa, a fuel consumption of 2 h ^-1 and a volume ratio of hydrogen / diesel fuel of 300. No. Chemical composition, wt.% Texture characteristics Catalytic performance CoO, wt.% NiO, wt.% MoO _3, wt.% P
Mass% Mo / Co (Ni), molar P / Mo, molar S _beats , m ² / g V _Σ , cm ³ / g D _cp , Å D _cf ± 15 Å,% Sulfur content, pmm X _S ,% Y% 340 ° 370 ° 340 ° 12. 4.6 - 21.3 1.2 2.4 0.26 150 0.31 85 fifty 380-400 85-90 440-450 96.4 96.2 96 13. 5.7 - 26.4 0.62 2.40 0.11 94 0.23 80 fifty 360-380 85-90 415-430 96.6 96.4 96 fourteen. 4.73 - 20.8 1.39 2.29 0.31 110 0.24 96 45 380-400 55-60 440-450 96.4 96.2 96 17. 5.85 - 27.0 1.74 2.40 0.3 81 0.21 75 45 380-420 55-60 440-480 96.4 96.0 96 Textural characteristics obtained from nitrogen adsorption isotherms: S _beats , m ² / g - BET specific surface area; V _Σ , cm ³ / g - pore volume, from nitrogen desorption isotherms; D _cp , Å — average pore radius; D _cp ± 15 Å,% - fraction of pores with a size of D _cp ± 15 Å; Catalytic characteristics: sulfur content in liquid petroleum products, ppm, at specified process temperatures; X _S ,% - degree of hydrodesulfurization at 340 ° C; Y,% - yield of liquid petroleum products at 340 ° C;

Claims (9)

1. The catalyst for the processes of hydrodesulfurization of diesel fractions, comprising an active component of metal oxides of VIII and VIB groups and phosphorus dispersed on an alumina carrier, characterized in that it contains a composition of aluminum oxide and montmorillonite in the following ratio, wt.%: Montmorillonite 5-15, alumina 85-95; as an active component contains, wt.%: molybdenum oxide MoO ₃ 14.0-29.0, cobalt oxide CoO and / or nickel oxide 3-8, phosphorus 0.1-0.5, the rest is the carrier with a molar ratio of Mo / Co and / or Mo / Ni 1.3-2.6 and P / Mo 0.08-0.1. 2. The catalyst according to claim 1, characterized in that the carrier contains a C - or Na-form of montmorillonite. 3. The catalyst according to claim 1, characterized in that it has the form of cylinders or trefoils. 4. A method of obtaining a carrier for catalysts for hydrodesulfurization of diesel fractions, characterized in that it includes the precipitation of aluminum hydroxide, the introduction of aluminum montmorillonite dispersed in water with a moisture content of 55-70% in an amount of 5-15 wt.% Based on the finished product, molding extrusion, drying and calcination at 500-600 ° C; and provides the carrier with a specific surface area of 200-300 m ² / g, a pore volume of 0.5-0.9 cm ³ / g, a predominant pore radius of 80-120 Å. 5. The method according to claim 4, characterized in that a peptizing additive of monobasic acid is introduced into the mass based on aluminum hydroxide and montmorillonite: nitric or acetic acid, in an amount providing an acid / Al ₂ O ₃ molar ratio in the range of 0.001-0.07. 6. The method according to claim 4, characterized in that as the montmorillonite use the C - or Na-form of montmorillonite. 7. A method of producing a catalyst for processes of hydrodesulfurization of diesel fractions, comprising impregnating a calcined alumina carrier with a complex solution of metal salts of groups VIII and VI of the Periodic system and phosphorus, followed by heat treatment in a stream of air or nitrogen at a temperature not exceeding 200 ° C, characterized in that the carrier contains composition of alumina and montmorillonite at a content, wt.%: montmorillonite 5-15, alumina 85-95, the impregnating solution contains molybdenum oxide and cobalt and / or nickel carbonate at m a molar ratio of Mo / Co and / or Mo / Ni equal to 1.3-2.6, stabilized with phosphoric acid and citric acid to a molar ratio of P / Mo in the range of 0.08-0.1, and a pH of the medium in the range of 1, 3-3.5. 8. A method for hydrodesulphurization of diesel fractions, which comprises passing a diesel fraction through a catalyst bed, characterized in that the catalyst according to claims 1 to 3 or the catalyst prepared according to claim 7 are used. 9. The method according to claim 8, characterized in that the process is carried out under the following conditions: partial pressure of hydrogen 3.5 MPa, temperature 300-370 ° C, mass flow rate of liquid 2 h ^-1 , the volume ratio of hydrogen / fuel is 300-500.