RU2140964C1 - Method of preparing low-sulfur petroleum factions - Google Patents

Abstract

FIELD: petrochemistry. SUBSTANCE: average distillate high-sulfur fractions are subjected to hydraulic refining in the presence of pack of alumooxide catalyst including protective layer of catalysts preactivated with sulfur- containing agent provided that catalyst pack comprises 2- 10 wt % of protective layer catalyst prepared by impregnation of aluminium oxide carrier calcined at temperature of not lower than 800 C and having 2-5 wt % of alpha-aluminum oxide, 73-75 wt % of beta-aluminium oxide and 25-10 wt % of γ- aluminium oxide formed as geometrical bodies having size of 8-20 mm and volume to surface area ratio of 1.0-2.5 cubric mm/sq mm with aqueous solutions of salts of active components followed by drying and calcination. EFFECT: longer intergeneration period of catalyst systems. 6 ex, 2 tbl

Description

 The invention relates to oil refining, in particular to methods for hydrotreating oil fractions.

 Known methods for hydrotreating petroleum distillates in a hydrogen medium using alumina-nickel and alumina-cobalt-molybdenum catalysts [US Pat. U.S. 4225418, Op. 30.09.80., Pat. RF 2005765, op. 01/15/94, Pat. US 4,177,136, op. 4.12.79.].

 A disadvantage of the known methods is the relatively low hydrodesulfurization activity during hydrodesulfurization of oil fractions, especially those containing unsaturated hydrocarbons. At the same time, it is known that one of the reserves for increasing the yield of distillate products during oil refining is the involvement of so-called substandard raw materials, in particular products of secondary origin, which contain a significant amount of unsaturated hydrocarbons, mechanical and other impurities. Processing of such raw materials at a hydrotreatment unit leads to a sharp decrease in the service life of traditional catalysts [B.K. Nefedov, E. D. Radchenko, R. R. Aliev. Catalysts for advanced oil refining processes. M: Chemistry, 1992, - 272 p.].

The closest in technical essence and the achieved result is a method of producing low-sulfur diesel fractions with a sulfur content of not more than 0.2 wt.% By hydrotreating diesel fractions at elevated temperature and pressure in the presence of a packet of alumina catalysts pre-activated in a medium of hydrogen-containing gas with elemental sulfur or raw materials at a temperature of 350-400 ^o C with the proviso that use packet alumina catalysts, containing from 10 to 100 wt.% of the catalyst alyumokobaltmolibdenovogo GO-70 / or GO-86, the activation of the catalysts is carried out with elemental sulfur, taken in an amount of not more than 30 wt.% by weight of the bag or with a distillate oil fraction with sulfur content S • (C + H) / C, where S is the sulfur content in the hydrotreating feed, C is the content of alumina-cobalt-molybdenum catalysts in the bag, wt.%; H is the content of aluminum-nickel-molybdenum catalyst in the bag, wt.% [US Pat. RF N2074877, publ. B.I. N 3, 1997].

 The disadvantage of this method is the relatively fast deactivation of the catalytic system when it is used in the hydrotreatment of high sulfur medium and heavy oil fractions, as well as in the processing of raw materials with a high content of unsaturated hydrocarbons and solids.

 The aim of the invention is to obtain a low-sulfur hydrogenate of middle distillate fractions, as well as an increase in the inter-regeneration period of catalytic systems in hydrodesulfurization reactions during the processing of heavy oil fractions and raw materials containing unsaturated compounds and solids.

This goal is achieved by the method of producing low-sulfur oil fractions by hydrotreating middle distillate fractions in the presence of a package of alumina catalysts, including a protective layer, pre-activated with a sulfur-containing agent, provided that the composition of the catalytic package includes 2-10 wt. % of the catalyst of the protective layer obtained by impregnating the carrier - alumina, calcined at a temperature of not lower than 800 ^o C and having in its composition 2 - 5 wt.% α-alumina, 73-85 wt.% δ-alumina and 25- 10 wt.% Γ-alumina, formed in the form of geometric bodies having a size of 8 - 20 mm and a ratio of volume to surface area of 1.0 - 2.5 mm ³ / mm ² , with aqueous solutions of salts of the active components, followed by drying and calcination.

A distinctive feature of the present invention is that the composition of the catalytic package includes 2-10 wt.% The catalyst of the protective layer obtained by impregnation of the carrier - 1. aluminum oxide, calcined at a temperature of at least 800 ^o C and having in its composition 2 to 5 wt. % α-alumina, 73-85 wt.% δ-alumina and 25-10 wt.% γ-alumina, formed in the form of geometric bodies having a size of 8-20 mm and a ratio of volume to surface area of 1.0 - 2.5 mm ³ / mm ² , aqueous solutions of salts of the active components, followed by drying and pro tracing.

 The use of a package of alumina catalysts described in the claims of the invention, including a predetermined amount of the catalyst of the protective layer having the characteristics specified in the claims of the invention, provides, firstly, protection of the main catalyst layer from mechanical impurities contained in the feedstock and, secondly, significantly reduces the formation of coke during the processing of raw materials with a high content of unsaturated hydrocarbons. The combination of these characteristics allows the preliminary hydrotreating of both heavier feedstocks and feedstocks containing unsaturated compounds and solids for a long period of time with a high volumetric rate without loss of activity and pressure drop across the hydrotreating reactor using the proposed catalyst.

 Certain ratios of the geometric shapes and sizes of the catalyst granules allow, when loading the catalyst, to achieve the optimum ratio of bulk density and hydrodynamic resistance of the catalyst layer, which has a significant effect on the distribution of the feed stream and maintains a high activity of the catalyst system without increasing the pressure drop across the reactor.

 In the known methods, the production of low-sulfur oil products using the described technologies is unknown.

 Thus, this technical solution meets the criteria of "novelty" and "significant difference".

 Examples.

 The protective layer catalyst is prepared as follows.

Sample 1. Prepare an impregnating solution. To do this, in 500 ml of water heated to 40 ^° C, 120 g of ammonium paramolybdate are dissolved with continuous stirring, 4 ml of phosphoric acid and 125 g of nickel nitrate are added to the resulting solution. Next, 0.5 kg of aluminum oxide, molded in the form of cylinders with a height of 20 mm and a diameter of 12 mm, containing 2 wt.% Α-alumina, 73 wt.% Δ-alumina and 25 wt.% Γ-alumina, is loaded into a container impregnation. The required crystallinity of the carrier is endowed with the composition of its crystallographic varieties (α, δ, γ), which is provided by heat treatment of the formed granules of aluminum hydroxide at a temperature of 850 ^o C. The loaded carrier is poured with an impregnating solution so that its level in the tank is 2-3 cm above the top level of the media. The duration of the impregnation at a temperature of 20 ^o C is 0.5 hours. The impregnated carrier is dried in air at room temperature for 6 hours, then kept in an oven at a temperature of 120 ^o C for 6 hours, while the rate of temperature rise in the range of 40-120 ^o C is 15 ^o C / h. The resulting drying product is calcined at a temperature of 400 ^° C. for 3 hours. The catalyst sample obtained in Example 1 contains 3.2 wt.% MoO ₃ and 1.1 wt.% NiO.

 Samples 2-6 are prepared in the same sequence and using the same impregnating solution as sample 1. In the preparation of sample 2, cobalt nitrate was used instead of nickel nitrate. In the synthesis of sample 4, only a nickel nitrate solution was used. Other features of the synthesis of samples 1 to 6 are given in table 1. Samples 1 to 4 are obtained in accordance with the claims. Samples 5 - 6 are made for exorbitant indicators.

 For the catalysts synthesized according to examples 1-6, the mechanical crushing strength, bulk density were determined and catalytic tests were carried out.

To determine the bulk density using measuring cylinders with a capacity of 500 cm ³ . The measuring cylinder is not weighed. The catalyst volume determined by shaking is weighed separately. With shaking, the cylinder is filled with 10-15 granules of catalyst granules taken from an average sample. The volume of up to 500 cm ³ occupied by granules is evaluated visually with an error of 5.0 cm ³ . The arithmetic mean of two determinations is taken as the test result if the difference between them does not exceed 0.05 g / cm ³ .

 The mechanical crushing strength is determined on a durable PC-2-1.0 meter.

When carrying out catalytic tests, a mixed diesel fraction of 180 - 360 ^o C with a sulfur content of 1.6 wt.%, Unsaturated hydrocarbons of 10 wt.%, And mechanical impurities of 1.2 wt.% Was used as raw material.

 The catalytic activity of the system was evaluated by the sulfur content in the hydrogenate and the pressure drop across the reactor after 100 and 500 hours of operation of the catalytic system.

 In the preparation of the catalytic package according to examples 1 to 8, GO-70 catalyst (TU 38.1011378-97) was used as alumina-cobalt-molybdenum catalyst, and RK-222 catalyst (TU 38.1011378-97) was used as aluminum-molybdenum catalyst.

 Activation of the catalytic system in all examples was carried out with elemental sulfur, taken in an amount of 10 vol.% The weight of the catalytic system.

 Examples 1 to 4 are made in accordance with the claims of the present invention, examples 5 to 6 are prohibitive, in example 7, ceramic balls were used instead of the catalyst for the protective layer. Example 8 is made according to the conditions of the prototype.

All examples were performed on a pilot plant with a total reactor volume of 1000 cm ³ with the following process parameters: temperature 340 ^o C, pressure 40 atm, volumetric feed rate - 5 h ^-1 .

 The direct composition of the catalytic package indicating the quality of the obtained hydrogenate according to examples 1-8 are given in table. 2.

 The list of catalytic systems used to evaluate the object of the invention, and the results are shown in table. 2.

 It can be seen that the examples made in accordance with the claims of the present invention (N 1 to 4) are significantly superior in activity in hydrodesulfurization reactions and lowering the pressure drop as catalytic systems containing a prototype (N 8) or traditionally used ceramic balls (N 7), as well as examples in which catalyst samples were used made according to transcendental parameters (N 5, 6).

Claims (1)

A method of producing low-sulfur oil fractions by hydrotreating high-sulfur middle distillate fractions in the presence of a package of alumina catalysts, including a protective layer, pre-activated with a sulfur-containing agent, characterized in that the catalyst package contains 2 to 10 wt.% Of the protective layer catalyst obtained by impregnating an oxide carrier aluminum calcined at a temperature not lower than 800 ^o C and having in its composition 2 - 5 wt.% α-alumina, 73 - 85 wt.% δ-alumina and 25 - 10 wt.% γ-alumina minium, formed in the form of geometric bodies having a size of 8 - 20 mm and a ratio of volume to surface area of 1.0 - 2.5 mm ³ / m ² , with aqueous solutions of salts of the active components, followed by drying and calcination.

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