RU2293107C1 - Petroleum fraction hydrofining process - Google Patents

Abstract

FIELD: petroleum processing.

SUBSTANCE: invention, in particular, relates to petroleum fraction hydrofining process utilizing presulfided catalysts. Hydrofining process is described involving contacting petroleum fractions with presulfided catalyst containing alumina-carried cobalt, molybdenum, phosphorus, and boron, said process being conducted at 320-340°C, pressure 3.0-5.0 MPa, volumetric feed supply rate 1.0-6.0 h-1, normalized volumetric hydrogen-containing gas-to-feed ratio (500-1000):1 in presence of catalyst sulfided outside of reactor. Sulfidizing of catalyst is accomplished with hydrogen sulfide at 80-500°C and volumetric hydrogen sulfide flow rate 0.02-6.0 h-1. Chemical composition of catalyst is the following, wt %: MoS₂ 8.0-17.0, Co₃S₂ 1.5-4.0, P₂O₃ 2.5-5.0, B₂O₃ 0.3-1.0, La₂O₃ 1.0-5.0, and aluminum oxide - the balance.

EFFECT: simplified process.

2 cl, 1 tbl, 3 ex

Description

The invention relates to the field of oil refining, in particular to the development of methods for hydrotreating oil fractions using pre-sulfidized catalysts.

Practice has shown that the optimal and most effective hydrodesulfurization of oil fractions is achieved by contacting the feedstock with sulfidized hydrotreating catalysts. The sulfidation process and activation of the catalysts is usually carried out in a catalytic reactor or outside using sulfiding agents and hydrogen. As a sulfiding agent, 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.

The sulfidation process, carried out directly in the catalytic reactor, is associated with corrosion of technological equipment, incomplete use of the working volume of the reactor, and a long time for putting the unit into operation.

From the patent No. 2102146 (RU IPC ⁷ V 01 J 37/04, publ. 20.01.98, Bull. 2) a method for hydrotreating oil fractions is known, carried out at a temperature of 250 ° C and 335 ° C. The composition of the used catalyst includes an alumina carrier, oxides of boron, molybdenum, nickel and phosphorus, the catalyst has a strength index of 2.2-2.5 kg / mm of the diameter of the granule. The implementation of the method provides a degree of desulfurization at a temperature of 335 ° C at the level of 91.9%, at a temperature of 250 ° C - 75.0%.

The disadvantages of the method are coking of the catalyst, the 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 methods is the use of a catalyst containing oxides of cobalt, molybdenum, aluminum and modifying compounds. Hydrotreating at high temperature.

From the analogue (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) a method for hydrotreating oil fractions is known. The known process of hydrotreating straight-run diesel fraction is carried out by contacting the raw material with a pre-sulfidized elemental sulfur alumina-cobalt-molybdenum catalyst with a sulfur content of 10% (from the initial catalyst). Sulfidation of the catalyst is carried out at a temperature of 120-180 ° C, after which the catalyst is cooled in a stream of nitrogen. The activation of the pre-sulfided catalyst loaded into the catalytic reactor is carried out with hydrogen. The process of hydrodesulphurization of a straight-run diesel fraction is carried out under the following technological conditions: hydrogen pressure - 3 MPa, bulk feed rate - 3 h ^-1 , hydrogen: feed - 200 m ³ / m ³ , temperature - 320, 330, 340, 350, 360 ° FROM. 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% by hydrodesulfurization in the presence of a pre-sulfidized catalyst is achieved at a temperature of 350 ° C.

The disadvantages of this method are:

- the complexity and duration of the manufacturing technology of the pre-sulfided elemental sulfur catalyst used in the future in the process of hydrotreating oil fractions,

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

- uneven sulfidation of the elemental sulfur processed by the elemental catalyst and problems arising in connection with this with its further use,

- 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 method of hydrotreating oil fractions according to the technical essence and the achieved result are the method known from patent No. 2185242 (RU IPC ⁷ B 01 J 37/20, C 10 G 45/08, publ. 20.07.2002). The known method is carried out by contacting the feedstock with a pre-sulfidized catalyst containing cobalt, molybdenum, phosphorus and boron deposited on alumina at elevated temperature and pressure. The activation process of the catalyst used for this 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 to 120-140 ° C, followed by treatment of the catalyst with hydrogen sulfide-containing gas at a temperature of 150-175 ° C and diesel fuel at a temperature of 250-330 ° C.

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 this method are:

- complex technology of the catalyst activation process;

- the use of manual labor, in the distribution of elemental sulfur in the catalyst layer;

- 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 range of hydrotreating processes using pre-sulfided catalysts.

The technical result of the invention is:

- simplification of the hydrotreatment process,

- reducing the duration of activation of the catalyst,

- reducing the initial temperature of the hydrotreatment process,

- more complete use of the working volume of the catalytic reactor,

- an increase in the inter-regeneration cycle,

- prevention of corrosion of an industrial reactor.

The claimed technical result in a method of hydrotreating oil fractions by contacting the feedstock with a pre-sulfidized catalyst containing cobalt, molybdenum, phosphorus and boron deposited on alumina at elevated temperature and pressure is achieved due to the fact that the process is carried out at a temperature of 320-340 ° C, the pressure is 3.0-5.0 MPa, the volumetric feed rate of 1.0-6.0 h ^-1 , the ratio of the Wash (hydrogen-containing gas): raw materials 500-1000 n./vol. raw materials, in the presence of a catalyst, sulfided outside the catalytic reactor with hydrogen sulfide at a temperature of 80-500 ° C and a space velocity of the supply of hydrogen sulfide 0.02-6.0 h ^-1 , the catalyst further includes lanthanum oxide in the following ratio, 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 1.0–2.0 m ³ precontact is placed on the catalyst layer — a protective layer consisting of corundum rings with an inner diameter of 5 mm.

A comparative analysis of the prototype and the claimed invention shows that a common feature of the known and claimed methods for hydrotreating oil fractions is contacting the feed with a pre-sulfidized catalyst containing cobalt, molybdenum, phosphorus and boron deposited on alumina at elevated temperature and pressure.

The difference of the proposed method from the known one is that the process is carried out at a temperature of 320-340 ° C, a pressure of 3.0-5.0 MPa, a volumetric feed rate of 1.0-6.0 h ^-1 , a ratio of VSG: raw material 500-1000 n.ob./about. raw materials, in the presence of a catalyst, sulfided outside the catalytic reactor with hydrogen sulfide at a temperature of 80-500 ° C and a space velocity of the supply of hydrogen sulfide 0.02-6.0 h ^-1 , the catalyst further includes lanthanum oxide in the following ratio, 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 1.0–2.0 m ³ precontact is placed on the catalyst layer — a protective layer consisting of corundum rings with an inner diameter of 5 mm.

The implementation of the proposed method 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, and prevent corrosion of the industrial reactor.

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

Example 1. The manufacture 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 Coo 3.0 P ₂ O ₃ 3.0 B ₂ O ₃ 0.5 La ₂ About ₃ 2.0 Aluminium oxide rest.

Example 2. Sulfidation of the catalyst.

Prepared according to example 1, the catalyst is contacted with hydrogen sulfide at atmospheric pressure outside the catalytic reactor. The sulfidation temperature is maintained at 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 About 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 process of hydrotreating diesel fuel.

The pre-sulfidized catalyst made according to Example 2, having the characteristics described above, is tested during hydrotreatment of diesel fuel. The conditions and test results of the pre-sulfidated catalyst are presented in table 1. For comparison and as a control, the data of the hydrodesulfurization process on the catalyst prepared by the method described above and sulfided with elemental sulfur are given. The hydrotreating process is carried out in a reactor into which a pre-sulfided catalyst is charged. A 1.0–2.0 m ³ precontact is placed on the catalyst layer — a protective layer consisting of corundum rings with an inner diameter of 5 mm. The purpose of the pre-contact is to evenly distribute the consumption of raw materials on the surface of the catalyst and to pre-clean the raw materials. Before starting the feed, the pre-grained catalyst loaded into the catalytic reactor is dried with nitrogen and activated with diesel fuel.

From the data of the table it follows that the 84.0-87.0% removal depth of sulfur compounds in the presence of a catalyst sulfidated outside the catalytic reactor with hydrogen sulfide has a catalytic activity at the level of the sulfided elemental sulfur catalyst. If sulfide-containing gas is used in the sulfidation process, no coke is deposited on the catalyst surface.

Implementation of the proposed method for 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 technological equipment.

Claims (2)

1. The method of hydrotreating oil fractions by contacting the feed with a pre-sulfidized catalyst containing cobalt, molybdenum, phosphorus and boron deposited on alumina at elevated temperature and pressure, characterized in that the process is carried out at a temperature of 320-340 ° C, pressure 3, 0-5.0 MPa, the volumetric feed rate of 1.0-6.0 h ^-1 , the ratio of WASH: raw materials 500-1000 n.v./about. raw materials in the presence of a catalyst sulfided outside the catalytic reactor with hydrogen sulfide at a temperature of 80-500 ° C and a space velocity of hydrogen sulfide supply of 0.02-6.0 h ^-1 , the catalyst further includes lanthanum oxide in the following ratio, 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 2. The method of hydrotreating oil fractions according to claim 1, characterized in that 1.0-2.0 m ^{3 of} precontact is placed on the catalyst layer — a protective layer consisting of corundum rings with an inner diameter of 5 mm.