RU2288035C1 - Presulfidized catalyst for hydrofining of petroleum fractions - Google Patents

Abstract

FIELD: petroleum processing.

SUBSTANCE: invention concerns development of catalysts for use in petroleum fraction hydrofining processes. Presulfidized catalyst including alumina-supported cobalt, molybdenum, phosphorus, and boron, active components of which are converted into operational sulfide form using sulfidizing agent, in particular hydrogen sulfide, at sulfidizing temperature 80 to 500°C and hydrogen sulfide volume flow rate 0.02 to 6.00 h^-1, catalyst further contains lanthanum oxide. Composition of catalyst is the following, wt %: MoS₂ 8.0-17.0, Co₃S₂ 1.5-4.0, P₂O₅ 2.5-5.0, B₂O₃ 0.3-1.0, La₂O₃ 1.0-5.0, and alumina - the balance.

EFFECT: simplified catalyst preparation technology without losses in catalytic and mechanical properties.

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Description

The invention relates to the field of oil refining, in particular to the development of catalysts for use in the hydrotreatment of petroleum fractions.

From patent No. 2197323 (RU, B 01 J 23/88, publ. 27.01.03), a catalyst for hydrotreating oil fractions is known, which has the following component composition, wt.%:

NiO or CoO 1.0-5.0 MoO ₃ 8.0-15.0 Modifying additives 0.01-5.0 Aluminium oxide Rest

As aluminum hydroxide, a dehydration product of an X-ray amorphous layered aluminum compound of the formula is used:

Al ₂ O _3n · H ₂ O,

where n = 0.3-1.5.

A modifying compound is one compound selected from the groups: phosphorus, fluorine, boron.

The patent No. 2102146 (RU, IPC ⁷ 01 J 37/04, publ. 20.01.98., Bull. 2) describes a catalyst for hydrotreating oil fractions, the composition of which includes an alumina carrier, oxides of boron, molybdenum, nickel and phosphorus.

The resulting catalyst has a strength index of 2.2-2.5 ^kg / _{mm of the} diameter of the granule and provides a degree of desulfurization at a temperature of 335 ° C at the level of 91.9%. When hydrotreating the benzene-toluene fraction, the degree of desulfurization at a temperature of 250 ° C is 75.0%. Due to coking of the catalyst, there is an urgent need for hydrogen activation 3-4 times a year in order to restore the activity of the catalyst.

Common features of the known and claimed catalysts is the content of cobalt, molybdenum, aluminum oxide and modifying compounds in their composition.

Practice has shown that the optimal activity of the catalysts described above is ensured by their complete sulfidation. The process of sulfidation and activation of the catalysts is carried out in a catalytic reactor or outside it using sulfidizing agents and hydrogen. As sulfidizing agents, a gas mixture of hydrogen sulfide and hydrogen, raw materials in a mixture with a sulfurizing compound, elemental sulfur, etc. are used.

The production of hydrogen sulfide-containing gas, necessary for the sulfurization of the catalysts loaded into the hydrotreatment reactors, is associated with great technological difficulties. Among the options for using various sulfur-containing compounds, which are the source of the formation of hydrogen sulfide, the most acceptable option is the use of elemental sulfur, loaded together with the catalyst. At temperatures above 120 ° C, molten sulfur is able to quickly penetrate into the pores of the catalyst and remain in it when cooled. In the atmosphere of a hydrogen-containing gas, hydrogenation of adsorbed sulfur occurs with the formation of hydrogen sulfide, which interacts with the catalyst with the formation of metal sulfides that make up the catalysts.

From the article (R.K. Nasirov, S.A. Dianova, N.A. Kovalchuk, I.R. Nasirov - Presulfidation of Hydrotreating Catalysts, - “Chemistry and Technology of Fuels and Oils”, 1998, No. 6, p.19- 22) known pre-sulfidized catalysts obtained by pre-impregnation of the hydrotreating catalyst with organosulfur compounds outside the process plant.

The sulfidation reaction between metal oxides and hydrogen sulfide released during the decomposition or hydrogenolysis of organosulfur compounds consists in the replacement of oxygen by metal oxides to sulfur with the release of water. Moreover, depending on the nature of the sulfur compound, coking of the catalyst can occur to a greater or lesser extent. In the case of the use of coke deposits on the surface of the catalyst in the process of sulfiding a hydrogen sulfide-containing gas, it does not occur.

The main disadvantages of the catalysts, pre-sulfidized by carbon disulfide, are environmental problems.

The pre-sulfurized hydrocarbon purification catalyst known from US Pat. No. 4,530,917 is made outside the catalytic reactor by contacting it with polysulfides of the general formula RS (n) -R ¹ , where n is an integer from 3 to 20, R and R ¹ are each of organic radicals having from 1 to 140 carbon atoms, R ¹ may be a hydrogen atom. As a promoter, it is recommended to add any aldehyde, or alcohol, or ketone, or organic acid to the polysulfides. These pre-sulfidized catalysts, during their use in the hydrotreatment process, are activated with hydrogen when hydrocarbons are loaded into the reactor.

Petroleum refining catalysts known from FR 2584311, including a support and active metal oxides, are subjected to preliminary sulfidation as follows. At the first stage, a sulfur compound based on organic polysulfides is introduced into the catalytic mass. In the second stage, sulfide oxidation of the active metal oxides in the presence of hydrogen is carried out at a temperature below 275 ° C. The activation of the catalyst is carried out with hydrogen at a temperature above 275 ° C.

A hydrocarbon processing catalyst is known from FR 2680704, comprising a support based on at least one metal or metalloid oxide and at least one active metal. The sulfonation of this catalyst is carried out in several stages. In the first, outside the catalytic reactor, the catalyst is treated with at least one sulfonating agent (for example, organic polysulfide) at a temperature of from 0 to 5 ° C in the presence of hydrogen. In the second stage, the catalyst obtained in the first stage is treated in the presence of hydrogen, or water vapor, or a moist inert gas also outside the reactor or in a catalytic reactor. At the first stage, it is recommended to add from 0.1 to 10 wt.% Halogen or phosphorus-containing compounds in an anhydrous organic medium.

From (Hallie Harman - Oil and Gas J., 1982, v. 20, No. 51, p. 69-74), pre-sulfidated catalysts are known, for the manufacture of which organic polysulfides, in particular di-tert-nonyl polysulfide, are also used.

Known from (R.K. Nasirov, S.A. Dianova, N.A. Kovalchuk, I.R. Nasirov - Presulfidation of Hydrotreating Catalysts, - “Chemistry and Technology of Fuels and Oils”, 1998, No. 6, p.19- 22) pre-sulfidized hydrotreating catalysts are prepared according to Eurecat Sulfikat technology by impregnating the catalyst with an organic polysulfide compound and holding it at elevated temperature. The activation of the pre-sulfidized catalysts is carried out in a catalytic reactor with hydrogen at a temperature of 300-350 ° C. Active metals (molybdenum, cobalt, nickel) in the catalysts pre-sulfidized by this technology are in the form of a stable intermediate oxysulfide.

The main disadvantages of the catalysts pre-sulfided by these agents are the high cost of the sulfur obtained and the need to strictly maintain the temperature of the hydrotreating process in a certain range.

A hydrotreating catalyst pre-sulfurized with elemental sulfur is known from US Pat. No. 4,177,136, and a hydrotreating, hydrocracking or tail gas catalyst pre-sulfidized by phased contacting the catalyst also with elemental sulfur at a temperature lower than the melting point of sulfur, heating the resulting sulfur-catalyst catalyst is known from US Pat. No. 4,177,136. mixture to a temperature above the melting point of sulfur. In this case, before heating the mixture to a temperature above the melting point of sulfur, it is recommended to first mix the sulfur-catalyst mixture with one substance selected from the group of high boiling oils or hydrocarbon solvents to form a moistened mixture.

Common features of the above known and the claimed catalysts is that they are alumocobalt-molybdenum systems, the active components of which are converted into a working sulfide form.

From (R.K. Nasirov, S. A. Dianova, N. A. Kovalchuk, I. R. Nasirov - Presulfidation of Hydrotreating Catalysts. - “Chemistry and Technology of Fuels and Oils”, 1998, No. 6, from 19-22) A pre-sulfidized alumina-cobalt-molybdenum hydrotreating catalyst for petroleum fractions is known, obtained using elemental sulfur as a sulfiding agent. The sulfidation process is carried out at a temperature of 120-180 ° C. The cooling of the catalyst is carried out in a stream of nitrogen. The activation of the pre-sulfidated catalyst loaded into the catalytic reactor is carried out with hydrogen. This hydrotreating catalyst with a sulfur content of 10% (from the initial catalyst) is tested in the process of desulfurization of a straight-run diesel fraction with the following technological parameters: hydrogen pressure - 3 MPa, bulk feed rate - 3 h ^-1 , hydrogen: feed - 200 m ³ / m ³ , temperature - 320, 330, 340, 350, 360 ° С. Straight run diesel fraction is characterized by the following indicators: density - 843 kg / m ³ at 20 ° C, fractional composition, ° C: n.k. - 179, 50% - 286, 90% - 360, c.k. - 367, sulfur content 1.2 wt.%.

The conversion of raw materials 95% during hydrodesulfurization in the presence of a pre-sulfidized catalyst is achieved at a temperature of 350 ° C.

The disadvantages of the known catalyst are:

- the complexity and duration of the manufacturing technology of the pre-sulfided elemental sulfur catalyst,

- the need for careful uniform distribution of elemental sulfur over the catalyst layer (almost impossible) using manual labor,

- uneven sulfidation of the elemental sulfur-treated catalyst,

- the possibility of excessive overheating of the catalyst and the need to strictly maintain the temperature regime throughout the volume and height of the catalyst layer,

- the occurrence of difficult to control temperature flashes causing catalyst deactivation due to the reduction of the oxides of hydrogenating metals to an inactive metal state,

- sinterability used for sulfidation of elemental sulfur,

- accumulation of water in the catalyst bed and the possibility of violating the physical integrity of the granules (cracking) and the working porous structure of the catalyst.

The closest (prototype) to the claimed pre-sulfidized catalyst for hydrotreating petroleum fractions according to the technical nature and the achieved result is a pre-sulfidized alumina-cobalt-molybdenum catalyst for petroleum hydroprocessing, known from patent No. 2185242 (RU, IPC ⁷ B 01 J 37/20, C 10 G 45/08 , published on July 20, 2002). The activation process of a known catalyst containing CoO, MoO ₃ , P ₂ O ₅ , B ₂ O ₅ , Al ₂ O ₃ , includes its treatment with elemental sulfur, loaded in layers in an amount of 1.0-2.5% by weight of the catalyst, which is heated up to 120-140 ° С followed by treatment of the catalyst with hydrogen sulfide-containing gas at a temperature of 150-175 ° С and diesel fuel at a temperature of 250-330 ° С.

The activation of the catalyst in the described way allows to improve the mechanical properties of the catalyst and increase its activity in the processing of heavy types of petroleum feed.

The disadvantages of the prototype are:

- complex technology of the catalyst activation process,

- the use of manual labor in the distribution of elemental sulfur over the catalyst bed,

- uneven sulfidation of the elemental sulfur-treated catalyst,

- the need for strict maintenance of temperature over the entire volume and height of the catalyst layer.

An object of the present invention is to expand the assortment with good catalytic properties of pre-sulfidated catalysts and sulfidizing agents suitable for sulfidizing catalysts outside a catalytic reactor.

The technical result of the invention is:

- simplifying the manufacturing technology of the pre-sulfidized catalyst,

- the exclusion of manual labor of personnel servicing the technological installation and the exclusion of direct contact of personnel with the impurity agent,

- more uniform and uniform sulfidation of the treated catalyst,

- carrying out the sulfidation process in a wider temperature range,

- preventing sintering obtained in the process of sulfidation of hydrogen sulfide sulfur, because it reacts immediately with the active components of the catalyst,

- preventing the accumulation of water in the catalyst bed and preventing the possibility due to this deactivation of the catalyst,

- obtaining pre-grained hydrotreating catalyst while maintaining good catalytic properties, characterized by high strength and a more uniform distribution of sulfur in the pores of the catalyst,

- preventing deposition of "coke" on the surface of the catalyst,

- reducing the duration of the sulfidation process, because Passed hydrogen sulfide quickly interacts with the catalyst with the formation of metal sulfides included in its composition.

Improving the consumer and operational properties of the proposed catalyst is achieved by reducing the duration of activation of the catalyst, the possibility of reducing the initial temperature of the hydrotreating process, more fully using the working volume of the catalytic reactor, increasing the inter-regeneration cycle, and preventing corrosion of the industrial reactor.

The claimed technical result from the implementation of containing on the alumina cobalt, molybdenum, phosphorus and boron pre-sulfidized hydrotreating catalyst for oil fractions, the active components of which are converted to a working sulfide form using a sulfidizing agent, is achieved due to the fact that sulfide is used as a sulfiding agent at a temperature sulfiding 80-500 ° C and the volumetric feed rate of hydrogen sulfide 0,02-6,00 h ^-1 and the catalyst additionally contains lanthanum oxide with the next . Regard, wt%:

MoS ₂ 8.0-17.0 Co ₃ S ₂ 1.5-4.0 P ₂ O ₅ 2.5-5.0 B ₂ O ₃ 0.3-1.0 La ₂ o ₃ 1.0-5.0 Aluminium oxide Rest

A comparative analysis of the prototype and the claimed invention shows that the common features of the known and claimed pre-sulfidized catalysts for hydrotreating oil fractions are their base containing cobalt, molybdenum, phosphorus and boron deposited on alumina, the active components of which are converted into a working sulfide form using a sulfiding agent.

The difference between the claimed catalyst and the known one is that hydrogen sulfide is used as a sulfidizing agent at a sulfidation temperature of 80-500 ° C and a space velocity of hydrogen sulfide supply of 0.02-6.00 h ^-1 , and the catalyst further includes lanthanum oxide in the following ratio of components , wt.%:

MoS ₂ 8.0-17.0 Co ₃ S ₂ 1.5-4.0 P ₂ O ₅ 2.5-5.0 B ₂ O ₃ 0.3-1.0 La ₂ o ₃ 1.0-5.0 Aluminium oxide Rest

In addition, a characteristic feature of the catalyst is the presence of a mixture of sulfides and oxides.

The proposed pre-sulfidized hydrotreating catalyst is characterized by improved operational and consumer properties, high strength, uniform distribution of sulfur in the pores of the catalyst, good hydrodesulfurization activity in the processing of petroleum feed containing large amounts of unsaturated hydrocarbons.

The implementation of the proposed catalyst allows to reduce the duration of activation of the catalyst, reduce the initial temperature of the hydrotreating process, more fully use the working volume of the catalytic reactor, increase the inter-regeneration cycle, prevent corrosion of the industrial reactor, and reduce the duration of the sulfidation process, because Passed hydrogen sulfide quickly interacts with the catalyst with the formation of metal sulfides included in its composition.

If sulfide-containing gas is used in the sulfidation process, no coke is deposited on the catalyst surface.

The possibility of implementing the invention is illustrated by the following examples.

Example 1. Preparation of the catalyst.

The catalyst is prepared by mixing 38.8 kg of aluminum hydroxide boehmite structure with 0.43 kg of boric acid and 1.3 kg of nitric acid solution of lanthanum carbonate. The resulting mass is stirred at a temperature of 30 ° C for 15 minutes. After obtaining a homogeneous mass, add 1.5 DM ³ 25% aqueous ammonia and the mass is stirred at 80 ° C for 20 minutes. The finished mass with a dry matter content of 50% is molded into granules with a diameter of 1.7 mm The formed granules are dried for 5 hours at a temperature of 120-200 ° C, and then calcined at a temperature of 450 ° C for 5 hours.

At the same time, an impregnating solution is prepared: 25 dm ^{3 of} water is poured into the solvent (tank), 1.7 dm ^{3 of} phosphoric acid and 5.6 kg of cobalt nitrate are added with continuous stirring at a temperature of 40 ° C. 6.5 kg of ammonium paramolybdate are charged into the resulting solution at pH 3.5.

Next, the granules of the catalyst are impregnated with compounds of the active components, which is carried out as follows. The calculated amount of the catalyst obtained by the method described above is loaded into the container, after which the calculated amount of an impregnating solution (40 ° C, pH 3.5) containing cobalt nitrate, ammonium paramolybdate and phosphoric acid is added from the measuring device. The catalyst impregnated with compounds of active components is dried at a temperature of 150 ° C and calcined at a temperature of 450 ° C.

Get the catalyst in the following ratio of components, wt.%:

MoO ₃ 11.0 Soo 3.0 P ₂ O ₃ 3.0 B ₂ O ₃ 0.5 La ₂ o ₃ 2.0 Aluminium oxide Rest

Example 2. Sulfidation of the catalyst.

Prepared by the method described above in example 1, the catalyst is contacted with hydrogen sulfide at atmospheric pressure. The sulfidation temperature is 120 ° C. over the entire length of the reactor. Sulfidation is carried out in batch mode for 10 hours at a volumetric rate of hydrogen sulfide feed of 0.05 h ^-1 .

Get pre-sulfidized catalyst in the following ratio, wt.%:

MoS ₂ 11.2 Co ₃ S ₂ 3.2 P ₂ O ₅ 3.0 B ₂ O ₃ 0.5 La ₂ o ₃ 2.0 Aluminium oxide Rest

The catalyst contains 3.9 wt.% Sulfur, has a strength index of 2.2 kg / mm of the diameter of the granule (norm at least 2.0 kg / mm), bulk density of 0.7 g / cm ³ .

Example 3

The pre-sulfidized catalyst prepared according to Example 2, having the characteristics described above, is tested during hydrotreatment of diesel fuel. The conditions and test results of the pre-sulfided catalyst are presented in the following table. For comparison and as a control, data are given on the hydrodesulfurization process in the presence of the inventive catalyst and on a catalyst sulfated with elemental sulfur.

From the data of the table it follows that the inventive catalyst has a catalytic activity at the level of a catalyst sulfated with elemental sulfur. This provides 84.0-87.0% removal depth of sulfur compounds.

The implementation of the pre-sulfidized catalyst in the process of hydrodesulfurization of oil fractions will reduce the duration of the output of the installation to the mode by 2-3 days and reduce the corrosion of process equipment.

Table Name of indicator Sulphidation Conditions hydrogen sulfide at 120 ° C elemental gray The temperature of the hydrodesulfurization process, ° C 320 330 320 330 Pressure, MPa 4.0 4.0 4.0 4.0 Volumetric feed rate, h ^-1 4.0 4.0 4.0 4.0 The ratio of WASH: raw materials, n.ob./about. raw materials 500 500 500 500 Mass fraction of sulfur,%: in raw materials - diz. fuel (L) 0.55 0.55 0.55 0.55 in hydrogenate 0.09 0.08 0.08 0,07 The degree of desulfurization, wt.% 84.0 85.0 85.0 87.0

Claims (1)

A pre-sulfidized catalyst for hydrotreating oil fractions, including cobalt, molybdenum, phosphorus and boron supported on alumina, whose active components are converted to a working sulfide form using a sulfidizing agent, characterized in that hydrogen sulfide is used as a sulfiding agent at a sulfidation temperature of 80-500 ° C and the volumetric feed rate of hydrogen sulfide 0.02-6.00 h ^-1 , the catalyst further comprises lanthanum oxide in the following ratio of components, wt.%: MoS ₂ 8.0-17.0 Co ₃ S ₂ 1.5-4.0 P ₂ O ₅ 2.5-5.0 B ₂ O ₃ 0.3-1.0 La ₂ About ₃ 1.0-5.0 Aluminium oxide Rest