RU2445163C1 - Catalyst of oil fractions hydrofining and method of its production - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to oil processing, in particular, to production of catalyst for extracting sweet oil fraction to be used in oil processing and petrochemistry. Proposed catalyst including commercial molybdenum disulphide and/or tungsten disulphide, as active components, produced by CBC-method with carrier, a nano-sized pseudo-boehmite, in 20:80 ratio or without, subjected to mechanical and chemical effects, promoter, e.g. nanopowders of 3D-metals (Ni, Co, Fe) produced by physical methods at active component-to-promoter ratio of 70:30 with particle size of smaller than 100 nm, and, additionally, gas-phase nanopowder of Ni in pyrocarbon shell with particle size of smaller than 10 nm in amount of 3 wt % of active component. Invention covers method of producing said catalyst in vertical vibration mill by mechanical and chemical activation of components at vacuum of 10^-5 torr with frequency and amplitude of vibration of 16 Hz and 2 mm, respectively, and activation time of 4-12 h.

EFFECT: higher activity of catalyst, ultralow content of residual sulfur in hydrodesulfuration products.

2 cl, 2 dwg, 1 tbl, 14 ex

Description

The invention relates to the field of oil refining, in particular to the creation of a catalyst for producing low-sulfur oil diesel fractions, and a method for its production and can be used in the oil refining and petrochemical industries.

It is known that the traditional sulfide catalyst for hydrotreating petroleum fuel fractions of the composition Ni- (Co) -Mo (W) -S / γ-Al ₂ O ₃ , which has been used for more than 50 years, is prepared by impregnating a porous support (γ-Al ₂ O ₃ ) a solution of the active component (salts of molybdenum, tungsten, cobalt, nickel). After the impregnation stage, the stages of drying, oxidation and activation of the system in a reducing medium are followed by sulfidation with hydrogen sulfide or dimethyl disulfide at temperatures of 400-800 ° C [H. Topsoe, BSClausen, FEMassoth Hydrotrearing Catalysis. - Germany, Springer, 1996]. The disadvantage of the applied catalyst systems is the complexity and laboriousness of the individual stages of manufacture, low environmental friendliness of the manufacturing procedure (a large amount of waste - aqueous solutions of inorganic reagents), as well as moderate desulfurization ability of the resulting catalytic systems. The development of modern supported catalysts based on Ni- (Co) -Mo (W) -S / γ-Al ₂ O ₃ is carried out in the direction of their improvement through the use of additional prescription and technological methods, namely by introducing various additives — zeolites, compounds zirconium, vanadium, titanium [Sh.K. Bej, SKMaity, UTTuraga // Energy & Fuels, Vol. 18, No. 5, 2004]; increasing the concentration of the active component by two-stage impregnation of a pre-calcined carrier [US Pat. 2246987, B01J 37/02, C10G 45/08, 27/02/2005] or the use of chelating compounds [Pashigreva A.V., Bukhtiyarova G.A., Klimov O.V., Noskov A.S., Polunkin I. M. // Oil refining and petrochemicals. 2007. Issue 10. S.19-23]; two stages of sulfidation [Sulfer in fuels: more stringent sulfer specifications for fuels are driving innovation. - Applied Catalysis A: General 248, (2003), 1-7], etc. These approaches ultimately do not allow increasing the activity of the catalysts by more than 1.5-1.7 times, which, in turn, prevents the production of fuel fractions with ultra-low sulfur content.

Catalysts are also known, the activity of which is 3-4 times higher than the supported catalysts. These are massive Nebula hydrotreating catalysts [Sulfur in fuels: more stringent sulfur specifications for fuels are driving innovation. - Applied Catalysis A: General 248 (2003) 1-7; M.I. Levinbuk, E. A. Kozyukov, A. A. Lebedev and others. On some problems of the Russian oil and gas complex. - Catalysis in industry No. 6, 2005, S. 3-18], which are obtained on the basis of molybdenum disulfide [GSStevens, T. Edmonds. J. Less-Common Met., 54, 321 (1977)]. Since molybdenum and tungsten disulfides in the coarse-crystalline state are characterized by chemical and catalytic inactivity [JV Lauritsen, J. Ibsgaard, S. Helveg, H. Topsoe et.all // Nature Nanotechnology. 2007. V.2. P.53-58 / www.nature.com/naturenanotechnology], then use the method of mechanochemical activation of the sulfide component [V.V. Molchanov, R.A. Buyanov. Mechanochemistry of catalysts. // Advances in chemistry. 69. No. 5. 2000. S. 476-493; Sulfer in fuels: more stringent sulfer specifications for fuels are driving innovation. - Applied Catalysis A: General 248, (2003)]. In accordance with numerous publications [JV Lauritsen, J. Ibsgaard, S. Helveg, H. Topsoe et.all // Nature Nanotechnology. 2007. V.2. P.53-58 / www.nature.com/naturenanotechnology; PRWentrcek and H. Wise, J. Catal, 1978, 51, 80] established that the transfer of MoS ₂ to the nanoscale state is accompanied by a change not only in the size, shape and morphology of the crystals, but also in the electronic structure, their reactivity and catalytic activity . The disadvantage of the described sulfide systems is that the studies performed mainly contain results regarding the assessment of the active surface of only single crystals of molybdenum disulfides of various shapes [M.Polyakov, S.Indris, S. Schwamborn et.all. Mechanochemical activation of MoS2-Surface properties and catalytic activities in hydrogenation and isomerization of alkenes and in H ₂ / D ₂ exchange Journal of Catalysis 260 (2008) 236-244] or MoS ₂ crystallites placed on substrates of gold, carbon or obtained in the form of furelin-like structures and nanotubes. Moreover, the presented results correlate with the activity of such catalytic systems in model reactions with respect to individual substances - in the reactions of isomerization and hydrogenation of alkenes, hydrodesulfurization of thiophene, dibenzothiophene and their derivatives.

It is well known that the classical catalyst for hydrotreating petroleum fractions contains not only Mo, W sulfides or a combination of them, but also promoters — most often Co, Ni, Fe, etc. In addition, in addition to the desulfurizing function, the hydrotreating catalyst must also have a deazotizing and hydrogenating ability , which requires the presence in addition to MoS ₂ and other components in the catalytic system.

Closest to the claimed catalyst and the method of its production - in composition (the presence of the active component and the promoter), as well as the method of influencing the constituent components during the preparation of the catalyst is a massive catalyst for the hydrotreatment of oil fractions [US Pat. RF 2346742 C1, B01J 37/04, B01J 23/85, B01J 23/88]. The catalyst is a solid-phase composition, which includes nickel hydroxocarbonate - nNi (OH) ₂ mNiCO ₃ , ammonium paramolybdate - (NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O, and ammonium metatungstate - (NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ obtained by physicochemical interaction by mechanochemical activation of components in apparatuses of mechanical and / or hydrodynamic action, preferably in a planetary centrifugal mill, at room temperature for 5-30 minutes, the mean free path of grinding bodies is 4.0-5, 0 cm, relative velocity of collision of chalk soluble bodies 17-34 m / s, the thickness of the reaction layer of the mixture of components on the surface of grinding bodies (0.4-2.6) × 10 ^-2 cm, followed by drying, calcination and sulfidation, and the drying of the active complex is carried out for 10-15 minutes. The disadvantage of the described catalyst is the residual sulfur content in hydrodesulfurizates ≥100 ppm, as well as the multi-stage process and the use of toxic dimethyl disulfide.

The objective of the invention is to obtain in one stage from the source of marketable products an effective catalyst that can significantly reduce the content of sulfur, nitrogen compounds, as well as polycyclic aromatic compounds in the process of hydrotreating a diesel fraction.

The technical result of the invention consists in increasing the efficiency of the catalyst in the process of hydrotreating a diesel fraction by increasing the hydrodesulfurization activity, the hydrogenating and deazotizing ability of the catalyst.

The technical result is achieved by the fact that the catalyst contains, as an active component, molybdenum and / or tungsten disulfide with or without nanosized pseudoboehmite in the ratio of 20:80, which are subject to mechanochemical action, as commodity or obtained by the SHS method (self-propagating high-temperature synthesis). sulfides of molybdenum and / or tungsten transform into a nanoscale state, and nanopowders of 3d metals (Ni, Co, Fe) obtained by physical methods at an active component and promoter 30:70 with a particle size of less than 100 nm, and, optionally, a gas-phase Ni nanopowder in a pyrocarbon shell with a particle size of less than 10 nm in an amount of up to 3% of the active component.

The method for producing the catalyst includes a one-stage solid-phase mechanochemical activation of the components in a vertical vibration mill under a vacuum of 10-5 Topp with a frequency and amplitude of exposure of 16 Hz and 2 mm, respectively, and an activation time of 4-12 hours; the product is stored in an inert atmosphere of argon. The optimal parameters of mechanochemical activation were determined experimentally.

As promoters, nanosized powders of Ni, Co, Fe, obtained by the methods of electric explosion of a conductor or gas-phase synthesis, the size of which does not exceed 100 nm, are used.

As an additive to the catalyst, which provides its hydrogenating ability with respect to aromatic compounds, gas-phase nickel nanopowder in a pyrocarbon shell with a particle size less than 10 nm is used. In accordance with the Raman spectrum (Fig. 1), which is represented by two peaks, the composition of the surface carbon shell of nickel powders corresponds to carbon in two states - diamond-like (sp ³ ) and graphene (sp ² ). In a graphene-like state, carbon is usually found in nanotubes. It is precisely this kind of specificity that can determine the hydrogenating function of nickel nanopowders in the pyrocarbon shell as part of the inventive catalytic systems.

As the carrier, nanosized commodity pseudoboehmite (γ-AlOOH) is used, which is obtained from electroexplosive aluminum nitride followed by its oxidation with water, separation, drying and calcination [Lerner MI, Svarovskaya NV, Psakhye SG, Bakina O.V. The technology of production, characteristics and some areas of application of electric explosive nanopowders of metals. Russian nanotechnology. 2009.V.4. No. 9-10. S.6-18]. The purpose of the carrier is to maintain the degree of dispersion of the active component and to ensure free access of reagents to active centers. In addition, the presence of a carrier of the nanoscale range in the catalytic system ensures the integrity of the catalyst at elevated temperatures, which is necessary for processes occurring in the diffusion region.

The catalyst efficiency tests were carried out on a straight run diesel fraction of the Ryazan Oil Refinery (boiling point temperature range 180-350 ° C; density 0.866 g / cm ³ , total sulfur content 1.18%; total aromatics content 30.86%; nitrogen 138 ppm); the sulfide sulfur content of 0.4%. The catalyst is prepared in the form of tablets, which are prepared by compression under a pressure of 250 kg / cm ² and which are then crushed and sieved through sieves, taking a fraction of 0.5-4 mm. The specified catalyst fraction is loaded into the reactor of a typical flow-through hydrotreatment unit in an amount of 4-5 g, providing a layer height of 6 ml Test conditions for laboratory flow-through installation - hydrogen pressure 4.0 MPa; H ₂ / feed ratio = 400: 1; feed rate of 40 ml / hour (as in the prototype); T = 390 ° C (temperature range of the hydrotreating catalysts is 340-400 ° C). The activity of catalytic systems in hydrotreating processes is estimated by the value of the residual content of sulfur, nitrogen, and aromatic hydrocarbons (AC) in hydrodesulfurizates. The elemental content of sulfur and nitrogen was determined on an Antek analyzer. The hydrogenating ability of the catalysts was evaluated by ¹ H NMR by the change in the fraction of aromatic protons in hydrodesulfurizates in comparison with the initial diesel fraction with subsequent conversion of the change in the content of aromatic hydrocarbons in%. The content of residual sulfur, nitrogen and a change in the amount of AC in the hydrogenates are given in table 1.

The catalyst is obtained in two types: 100% active component and 20% active component + 80% carrier.

Case Studies

Example 1. The composition of the catalyst — only the active component without carrier — 4.2 g of MoS ₂ and 1.8 g of Ni NP (the ratio of active component to promoter as 70:30) is loaded into a steel mortar of a vertical vibratory mill, the amount of powder in one load is 6 g, balls are made of ball-bearing steel, the mass of balls is 200 g. Air is pumped out of the mortar with balls and powder to a level of 10 ^-5 Torr, then the mortar is mounted on a frame that vibrates with a frequency of 16 Hz and an amplitude of 2 mm. Activation time 4 hours. Then the chamber is filled with Ar, the catalyst is discharged and stored in an inert atmosphere.

Example 2. The composition of the catalyst — only the active component without carrier — 8.4 g of MoS ₂ and 3.6 g of Ni NP (the ratio of active component to promoter as 70:30) is loaded into a vibratory mill mortar, the amount of powder in one load is 12 g in total The balls are made of ball-bearing steel, the mass of the balls is 200 g. Air is pumped out of the mortar with balls and powder to a vacuum of 10 ^-5 Torr, then the mortar is mounted on a frame that vibrates at a frequency of 16 Hz and an amplitude of 2 mm. The mechanical activation time is 8 hours. Then the chamber is filled with Ar, the catalyst is discharged and stored in an inert atmosphere.

Example 3. Similar to example 1, but instead of NP Ni took NP Co.

Example 4. Similar to example 1, but instead of NP Ni took NP NP.

Example 5. Similar to example 1, but to the indicated components — MoS ₂ and NP Ni, another nickel nanopowder in the pyrocarbon shell, NP Ni (C), was added in an amount of 3% of the active component, i.e. the composition of the catalyst is [3% (0.18) g NP Ni (C) + 97% (4.07 g MoS ₂ +1.75 g NP Ni)], with the ratio of active component and promoter as 70:30; the total number of catalytic components in one load of 6 g. The time of mechanical activation of 5 hours.

Example 6. Similar to example 5, but the total amount of catalytic components in one load of 12 g; the composition of the catalyst is [3% (0.36) g NP Ni (C) + 97% (8.14 g MoS ₂ +3.49 g NP Ni)], with the ratio of active component and promoter as 70:30. The mechanical activation time is 5 hours.

Example 7. Similar to example 1, but instead of commercial MoS ₂ they took molybdenum disulfide obtained by the SHS method.

Example 8. The catalyst consists of two components - "active component + carrier". The preparation procedure is similar to Example 1, but they only take the active component 20% [0.84 g MoS ₂ +0.36 g NP Ni (MoS ₂ : Ni ratio = 70: 30)] and add 80% of the carrier - 4.8 g AlOOH . The components are loaded into a vibratory mill, the amount of powder in one load (total) 6 g. Mechanical activation time 7 hours.

Example 9. The catalyst consists of two components - "active component + carrier". The preparation procedure is similar to Example 8, but they only take the components in one load in a total amount of 12 g. Catalyst composition: 20% [1.68 g MoS ₂ +0.72 g NP Ni (MoS ₂ : Ni ratio = 70: 30)] + 80% (9.6 g) AlOOH (carrier)]. The mechanical activation time is 7 hours.

Example 10. Similar to example 6, but to the indicated components — MoS ₂ , Ni Ni, and also AlOOH support — 3% Ni (C) nanopowder was added, i.e. the catalyst has the composition - [3% (0.18 g) NP Ni (C) + 19.4% [0.81 g MoS ₂ +0.34 g NP Ni (ratio MoS ₂ : Ni = 70: 30) +77 6% (4.65 g) AlOOH]; the total number of catalytic components in one load of 6 g. The mechanical activation time is 8 hours.

Example 11. Similar to example 10, but the total amount of catalytic components in one load of 12 g. The catalyst has the composition - [3% (0.36) g NP Ni (C) + 19.4% (1.62 g MoS ₂ +0 70 g NP Ni (MoS ₂ : Ni ratio = 70: 30) + 77.6% (9.31) g AlOOH]. Mechanical activation time 8 hours.

Example 12. The catalyst according to the composition and preparation conditions of the catalyst, as in Example 5, but only instead of MoS _{2 was} taken WS ₂ , namely [3% (0.18) g NP Ni (C) + 97% (4.07 g WS ₂ +1.75 g NP Ni], the ratio of active component to promoter is 70:30; the total load of catalytic components is 6 g.

Example 13. The catalyst according to the composition and preparation conditions, as in Example 12, but the total amount of catalytic components in one load of 12 g and the composition of the catalyst is [3% (0.36) g NP Ni (C) + 97% (8.14 g WS ₂ +3.49 g NP Ni) (ratio of active component and promoter as 70:30)]; total amount of catalytic components in one load of 12 g.

Example 14. The catalyst according to the composition and preparation conditions, as in Example 13, but instead of MoS _{2, the} mixture (MoS ₂ + WS ₂ ) was taken as the active component, ie, the composition of the catalyst was [3% (0.36) g NP Ni (C) + 97% (4.07 g MoS ₂ + 4.07 g WS ₂ ) +3.49 g NP Ni) (ratio of active component and promoter as 70:30)].

Thus, the proposed catalysts have a high desulfurizing, deazotizing, and also hydrogenating abilities, providing an ultralow content of residual sulfur in the final hydrodesulfurizates — less than 50 ppm; nitrogen - less than 25 ppm, and also reduce the content of aromatic hydrocarbons by 5-10%.

The effect of high activity of the catalysts is achieved through the implementation of the method for their preparation — solid-phase interaction of the components of the catalytic systems under mechanical activation and the direct formation of the catalytic system in the nanoscale state (FIG. 2), use of nanoscale metal powders obtained by the methods of electric explosion of a conductor or gas-phase synthesis as promoters of using nanosized nickel powders in a pyrocarbon shell as an additive providing hydrir the ability of the catalyst.

In this invention, a variant of the realized mechanochemical activation as a method of producing a catalyst is more effective from the point of view of dispersion, as evidenced by the nanoscale particle range of the resulting catalysts, in contrast to the "micron", as in the prototype.

The solid-phase components of the catalyst, which are subjected to mechanochemical effects, are initially active components and promoters, but not their predecessors, which eliminates the stages of preparation of the catalytic system, namely, drying, calcination, and also the activation stage, which is the sulfidation of the catalyst precursors.

Catalyst sample Temperature ° C Residual Content AU content reduction, in% S ppm N ppm By Prototype 360 one hundred Not given Not given Example 1 390 27 31 5 Example 2 390 thirty 28 6 Example 3 390 70 38 5 Example 4 390 81 48 5 Example 5 390 Less than 10 25 10 Example 6 390 Less than 10 25 10 Example 8 390 13 25 10 Example 9 390 10 27 10 Example 10 390 Less than 10 25 10 Example 11 390 Less than 10 26 10 Example 12 390 53 40 3 Example 13 390 fifty 44 four Example 14 390 Less than 10 twenty eleven

Claims (2)

1. The catalyst for hydrotreating oil fractions containing molybdenum and / or tungsten compounds and a promoter, characterized in that it contains commodity molybdenum and / or tungsten disulfide or obtained by the SHS method as an active component, with a carrier - nanosized pseudoboehmite in a ratio of 20:80 or without it, subject to mechanochemical effects, the catalyst contains 3d metal nanopowders (Ni, Co, Fe) obtained by physical methods as promoters, with a ratio of the active component and the promoter of 70:30 with a part size q less than 100 nm and, optionally, a gas-phase nanopowder Ni in a pyrocarbon shell with a particle size of less than 10 nm in an amount of 3% of the active component. 2. The method of preparation of the catalyst according to claim 1, comprising mechanochemical activation of the components, characterized in that the process is carried out in a vertical vibration mill under a vacuum of 10 ^-5 Torr with a frequency and amplitude of exposure of 16 Hz and 2 mm, respectively, and an activation time of 4-12 hours, while the product is stored in an inert atmosphere of argon.

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