CS211489B1 - Method of hydrogenous demetalization of heavy crude oil distillates and residue crude oils - Google Patents

Description

The invention relates to a process for the hydrotreating of heavy petroleum distillates, residual petroleum oils containing heavy metals, in particular vanadium V and nickel Ni above 100 ppm and asphaltenes above 3% by weight. and similar feedstocks on a fixed catalyst.

Currently, there are a number of technological processes designed for the catalytic hydrotreatment of petroleum distillation residues. Catalytic hydrotreatment of petroleum distillation residues is known to result in much faster catalyst deactivation as a result of the elimination of coke-forming substances and especially trace metals such as V, Ni, Fe, Ca, Na, which are present in the feedstock as oil-soluble metal-organic compounds. These oil-soluble metalloorganic compounds are largely concentrated in the heaviest proportions of petroleum residues - in their non-distilling asphaltenic portion.

In comparison with carbonaceous deposits which can be removed from the catalyst during its regeneration, for example with a steam-blended mixture, metal deposits which cause a permanent loss of catalyst activity cannot be removed in this way. As soon as the trace metal accumulation on the catalyst reaches a certain limit, there is a deeper loss of activity and the catalyst must be replaced with fresh. The rapid deactivation of the catalyst results in its relatively high specific consumption. Conventional regeneration procedures are poorly effective. Vanadium deposited on the catalyst results in regeneration with a vaporized mixture of V ₂ O 3, which catalyses the oxidation of SO ₂ to SO 3, causing sulphation of the carrier in a humid environment, which also leads to irreversible harmful changes.

Vanadium compounds also cause extensive damage when the oil residues are used as fuel oils due to corrosion of the combustion plant.

An attempt to limit the beneficial effect of metalloorganic compounds on the activity and durability of hydrotreating catalysts very often leads to the choice of a two-stage process where some of the organometallic compounds and asphaltenes are removed in the first step. The process according to German Patent No. 1,770,996 involves a two-stage catalytic hydrogenation of petroleum residues, in which in the first stage the use of a porous AlgO4 -SiOg catalyst converts asphaltenes and metalloorganic compounds of trace metals. A similar procedure is the subject of U.S. Pat. No. 3,180,820. In the first step, a Ni-10 supported AlgO4 -SiOg supported catalyst is used. Demetallization contact based on manganese modules (extracted from the seabed) is the subject of German patent No. 2 235 954.

British Patent No. 736,382 protects the demetallization process for oil residues and utilizes .... bauxltu as a demetallization contact. Deutsche Texaco recommends the use of natural clays as demetallization contacts. German Patent No. 2,421,978 discloses Attapulgit clay-based demetallization contact.

As a carrier of demetallization catalysts, widely -oporous alumina is often recommended. According to U.S. Pat. No. 3,931,052 it is recommended to use a catalyst comprising Group VI and Group VIII metals deposited on alumina with a maximum pore proportion of 1.80 to 30.0 nm in diameter. Alumina with a mean pore radius above 5.0 nm is recommended as a support for a demetallization catalyst in British Patent No. 1,438,645. SiOg is also recommended from other demetallization catalyst supports. According to German Patent No. 2,447,303, a catalyst containing 0.5% Ni and 2% V deposited on SiO2 is preferred for demetallization.

Common to all these processes is that they only allow partial demetallization, which, together with the relatively high cost of the demetallization catalyst, makes these processes uneconomical.

A process has now been applied for the hydrotreating of heavy petroleum distillates and residual petroleum oils containing metals, in particular vanadium V, nickel Ni above 100 ppm and asphaltenes above 3% by weight, or other similar raw materials, on a fixed or movable catalyst at a pressure of 4, 4 to 34.3 MPa, preferably at 9.8 to 14.7 MPa, a temperature of 350 to 450 ° C, preferably 380 to 430 ° C, a bulk rate of 0.3 to 3, preferably 0.5 to 1 hour, and A ratio of hydrogen to feedstock of 500 to 1,800, preferably 500 to 1,000 Nm < 2 > / m < 2 >, comprising contacting the feedstock with hydrogen and catalyst with a total pore volume above 0.10 ml / g, preferably above 0.20 ml / g, and with a specific surface area above 50 m ² / g, preferably above 100 m ² / g, shaped into tablets, hollow or solid extrudates with an outer diameter of up to 10 mm, preferably 2 to 5 mm.

A product with a reduced trace metal content of vanadium V, nickel Ni, sulfur S, asphaltenes and a substantially lower viscosity can be advantageously hydrogenated in the next step using commercially produced low-sulfur fuel or motor fuel catalysts using a fission hydrogenation process.

Natural or synthetic clays, alumina, aluminosilicates, deactivated hydrotreating catalysts, etc. can be used as the demetallization contact. Natural bentonite has been selected from a number of natural materials tested as demetallization contacts.

Bentonites are natural clayey soils whose main substance is the montmorillonite mineral. Montmorillonite is a hydrosilicate with a layered structure, high sorption ability and a large specific surface area. The Si: Al ratio can vary from 2: 2 to 6: 2 for each montmorillonite type. E.g. bentonite from the Braňany site has the following composition:

211 + 89

Content SiO ₂ 41.0 wt. ai ₂ o ₃ 17.0 wt. Tío ₂ 5.3% ienol. Fe ₂ O 4 18.5 wt. Na ₂ O 0.07 wt. MgO 2.5 wt. CaO 1.6 wt. K ₂ O 0.2 wt. Loss on ignition at 800 ° C 13.6 wt.

The different types of bentonites are determined by the different content of montaorillonite and the content of accompanying substances, which changes the properties of bentonite. However, the usefulness of the bentonite for preparing the contact is not affected, and of course the catalyst activity changes.

It was been discovered, that when subjected to this material a simple processing in which the finely ground material is mixed with (NH ^) ₂ ^C0 3 »peptizuje acid formed e.g. in výtlačk.ů and thermally treated at 450 to 950 ° C, contact with good demetallization properties is obtained.

Bentonite base contact is considerably cheaper compared to commercially produced hydrotreating catalysts. After exhausting the activity, it is recommended to replace it for fresh contact. The deactivated contact contains 8 to 12% V and is therefore a valuable raw material for obtaining this metal.

An important feature is that the hydrodemetallization takes place in a reactor with fixed particle contact as the reacting components flow from bottom to top. Compared to the flow of hydrogen and hydrocarbon feedstock from top to bottom, considerable flow is achieved from bottom to top. advantages, in particular due to a more uniform distribution of trace metals along the catalyst bed, longer working periods between the eyenets are achieved. regeneration - catalyst. A comparable conversion of the hydrocarbonaceous feedstock is achieved at a lower initial working temperature and, under the same conditions, a deeper conversion of trace metal compounds and asphaltenes is achieved.

The following example shows the advantages of the proposed procedure:

He did

The demetalization activity of the bentonite-based contact was tested in an experimental hydrogenation of the oil in a 200 ml catalyst. Demetallization contact testing was performed under the following conditions:

Pressure 14.7 MPa

Temperature 370-420 ° C

Volumetric speed 0.5 to! hod ^- '

H ₂ / CH ratio 1000 Nl / L

In the first part of the experiment, which was conducted at a temperature of 400 ° C and a volumetric velocity of LHSV = 1, the contact was incorporated to achieve some equilibrium activity. The length of this part of the experiment was 200 hours. Another part of the experiment, which was operated at a volumetric velocity of LHSV = 0.5 h -1 and a temperature of 370 to 420 ° C, served to assess the temperature sensitivity of the contact activity. Each condition was run for 72 hours.

In the experiments the atmospheric distillation residue was used. The raw material used had the following properties:

density 0,951 sulfur content,% wt. 2.43 nitrogen content,% by weight 0.29 Konradson carb. %, wt. 8.3 content of asphaltenes ^x ), wt. 3.2

Trace metals: vanadium ppm 101.3 nickel ppm 33.3 iron ppm 16.3 sodium ppm 12.6

^(x ) determined using n-heptane

The catalyst used has the following characteristics:

Table

Contact designation C Addition (NH ₄ ) ₂ CO ₃ 10% Annealing temperature ° C 500 bulk density g / l 800 specific surface area m ^ / g 117.1 pore volume ml / g 0.23 volume of mesopores ml / g 0.22 volume of aacropores ml / g - mean radius of mesopores nm 1.26 degree of demetallization ^x )% 76.2 degree of desulfurization ^x )% 39.9

^x ) determined at 420 ° C and LHSV - 0,5 h '

The following table shows the results of the hydro-metallization of the black oil in the flow of hydrogen and feedstock from bottom to top.

T a. B u 1 k a 1

Reaction temperature ° C 400 370 395 420 LHSV volume rate 1.0 0.5 0.5 0.5 Hydrogen product properties: 20 May specific gravity h 0,930 0,942 0,934 0,910 sulfur content wt. 1.72 2.17 2.01 1.46 desulphurisation degree% 29.2 10.1 17.3 39.9 Conrad, carb. % wt. 6.1 6.9 5.2 4.8 viscosity Pa.sec./100 ° C 38.2 19.8 6.6 Trace metals ppm: vanadium 60.5 67.4 51.4 20.8 nickel 23.7 29.2 21, 9 11.3 iron 10.2 8.8 12.1 8.2 sodium 0.5 0.5 0.4 1.6 Degradation of vanadium% 40.3 33.5 49.3 79.5 degree of nickel degradation% 28.8 12.3 34.2 66.1 HDS HDMe 0,778 0.379 0.380 0.524 content of asphalts 2.8 2.8 1.9 0.5

The results of the experiment show that under the process conditions a high degree of demetallisation can be achieved with the bentonite-based detnetalization contact in the region of temperatures of 400 to 420 ° C to degrade asphalts.

Example 2

Two comparative experiments were performed using activated bentonite as a catalyst to compare the effects of the up and down streams of reactants in the reactor. The experiments were carried out at a pressure of 14.7 MPa, a volumetric velocity of 0.5 hrs and a gas to feedstock ratio of 1000 Hl / l. In both experiments, the reaction temperature was maintained such that 50% demetallization was achieved. The results are listed in the following overview.

Direction of flow of reactants in the reactor downward upward initial temperature ° C 408 400 temperature after 500 hours of experiment ° C '420 414 contact aging speed ° C / hour 0.024 0,028

The above overview shows that in the experimental flow arrangement, 50% of the feedstock has been demetallized at a practically equal aging rate of the contact at a lower temperature reaction, which is a prerequisite for achieving a longer working period of contact.

Claims (2)

Process for the hydrotreating of heavy petroleum distillates and / or residual petroleum oils containing heavy metals, in particular vanadium V, nickel Ni above 100 ppm and asphaltenes above 3% by weight, or other similar raw materials, on a fixed catalyst, at a pressure of 4, 4 to 34.3 bar, preferably 9.8 to 14.7 MPa and a temperature of 360 to 450 ° C, preferably 380-425 ° C, space velocity of 0.3 to 3, preferably 0.5 to 1 hour ^- ' and a hydrogen to feedstock ratio of 500 to 1800 nP / m < 2 > preferably 50 to 1000 < tb > / y, characterized in that the feedstock is contacted with an activated bentonite catalyst with a total pore volume above 0.10 ml / g , preferably above 0.20 ml / g, and with a specific surface area above 50 m / g, preferably above 100 m / g, shaped in the form of tablets, hollow or solid extrudates with an outer diameter of up to 10 mm -1, preferably 2 to 5 mm. 2. The process according to claim 1, wherein the hydrocarbon feedstock is contacted with the particle contact in the reactor in a bottom-up flow.