FR2538812A1 - Use of a supported catalyst for the hydrotreatment of a hydrocarbon feedstock - Google Patents

Abstract

Use of a supported catalyst containing vanadium, molybdenum, tungsten, nickel and/or cobalt in hydrotreatment reactions of residual hydrocarbon oils, such as hydrogenation, hydrodesulphurisation, hydrodenitrogenation and hydrodemetallation. This catalyst has the characteristic of being prepared from a support with a remarkably low cracking activity. Use of alumina for the manufacture of the support.

Description

 The present invention describes a process for the hydrotreating of hydrocarbon feeds containing metals, asphaltenes and / or resins as impurities.

 Examples of such feedstocks are crude oils, atmospheric residues, vacuum residues, deasphalted oilswhich still contain resins and / or metals, or pitches and asphalts diluted with aromatic distillates.

 It is known that the usual catalysts are poorly suited to the treatment of such fillers, since they have a metal content (nickel, vanadium, iron, titanium, etc.) as low as 10 parts per million (10 parts per million). ppm). They deactivate quickly as soon as the deposit of metals reaches 50% (sometimes 20%) of the initial weight of the catalyst.

 The invention is based on the surprising discovery of the good resistance to poisons, such as metals, asphaltenes and / or resins catalysts obtained by depositing at least one of the metals: vanadium, molybdenum, tungsten, nickel and cobalt, or at least one of the compounds of these metals, on a neutral support.

 The neutrality of the support can be determined by the heptane test.

The cracking test of n-heptane consists in measuring the amount of n-heptane converted into lighter molecules under the following operating conditions
- fixed bed unit crossed
- total pressure: 10 bar
- H2 / n-heptane: 4
- space velocity: 1.5k hydrocarbon catalyst 1kg
sor / hour
- temperature: 4700C 500 "C
The conversion is measured by gas chromatographic analysis of the liquid products.

 In this test, a carrier is said to be neutral if its cracking activity (mole / hour / m 2 of support) is less than 5 × 10 -6 at the temperature of 47 ° C. and if it is less than 15 × 10 6 at the temperature of 50 ° C.

 The support may be, for example, a silica, a silica-alumina, a clay or, preferably, an alumina chosen for its neutrality vis-à-vis the test with heptane or that has been modified to give it neutrality desired.

 A particular method for conferring this neutrality is to leave sodium ions in the support, during its preparation, or to introduce these ions later. For example, an Na2O content of 1000 ppm by weight, or higher, is generally sufficient. Another method is to introduce a calculated amount of silica. A third method is to introduce rare earth metals or vanadium sulphide.

 These methods are given by way of examples and can not in any way limit the scope of the invention, the condition to be satisfied remaining in all cases the inertia in the heptane test.

 The catalysts which can be used according to the invention usually have a pore volume of 0.7 to 2 cm 3 / g and a surface area of 50 to 250 m 2 / g.

The catalytic metals, vanadium, molybdenum, tungsten, nickel and / or cobalt, are introduced into the catalyst in a preferred proportion of 5 to 30%, expressed by weight of the oxides V 2 O 5, MoO 3, WO 3>
NiO and CoO.

 This introduction is realized according to; known techniques, for example impregnatioapar kneading and extrusion or pelletizing. Particularly useful compounds for carrying out this introduction are nitrates and acetates of nickel and cobalt, molybdate, tungstate and vanadate diammonium.

 After introduction of the active metal compounds, it is shaped, if necessary, and dried and activated by heating at about 300-6000C.

 At the time of use it is usefully treated with hydrogen or, better, hydrogen supplemented with hydrogen sulfide. A hydrogen sulphide content of 2 to 10% by volume is generally sufficient.

 The catalysts thus obtained can be used anyway as, for example, as a fixed bed, mobile, expanded or dispersed. The advantage of the above catalysts is to have a high resistance to the poisons of the charges, especially metals. They can withstand metal deposits reaching or exceeding 100% of the initial catalyst weight.

 The catalysts thus defined find a particularly useful use in the treatment of hydrocarbon feeds which contain metals, asphaltenes and / or resins, in order to eliminate or reduce the harmfulness of these undesirable constituents.

They simultaneously make it possible to eliminate other undesirable constituents such as the compounds of sulfur, oxygen and / or nitrogen.

 The hydrotreatment conditions usually comprise a temperature of 370 to 470.degree. C., a pressure of 50 to 200 bar, a space velocity of 0.2 to 5 volumes per volume of catalyst and an hour, the hydrogen gas ratio on a hydrocarbon liquid feedstock. from 200 to 500 vol / vol.

Example 1
Two catalysts A and B are prepared respectively from the supports A 1 and B 1.

 The support A 1 is obtained by agglomeration of a powder of alumina rotating bezel. The alumina powder was previously added with pore-forming agents. The beads thus obtained have a diameter of between 2.4 mm and 4.0 mm> undergo a steam treatment at a temperature of about 250 C for 2 hours (self-claving), then a drying time of 2 hours at 110 ° C. and a calcination for 2 hours at 800 ° C. Moreover, this alumina powder contains 1200 ppm Na 2 O by weight.

 The support B 1 is also obtained by agglomerating an alumina powder in a rotating bezel, this alumina powder also containing blowing agents and then drying and calcining as above. Balls having a diameter of between 2.4 mm and 4.0 mm are thus obtained. The Na2O concentration of this alumina is 300 ppm.

The textural characteristics of these two media are the same
- surface area: 170 m2 / q
total pore volume: 1.05 cm3 / g
The two catalysts are then prepared according to the same impregnation protocol in two steps: 85 g of ammonium heptamolybdate are dissolved in 340 cm3 of distilled water by heating at 600C. Separately 58 g of nickel nitrate are dissolved in 340 cm3 of distilled water at room temperature. The two solutions thus prepared are mixed and the total volume of the mixture is brought to 1050 cm3 at 25 ° C. by adding water This solution is immediately put in contact with 1 kg of the support to be impregnated.

The thus impregnated support is maintained in a humid atmosphere for 12 hours. The catalyst thus prepared is then dried in a stream of dry air at 110 ° C. and then calcined for 2 hours at 5000 ° C. in a rotary kiln.
The composition of the two catalysts is then:
Al 2 O 3 = 91.5% MoO 3 = 7% NiO = 1.5%
The cracking test of n-heptane described above is carried out on both supports A 1 and B 1, the results obtained are shown in Table I.

Table I

<tb> Support <SEP> A <SEP> 1 <SEP> B <SEP> 1
<tb> Temperature <SEP> 4700C <SEP> 5000C <SEP> 4700C <SEP> 500C <SEP>
<tb><SEP> activity of <SEP> cracking <SEP> 0.5.10-6 <SEP> 8,0.10-6 <SEP> 6,0.10-6 <SEP> 18,0.10-6
<tb> (mole / h / m <SEP> of <SEP> support)
<Tb>
It therefore appears that the support of catalyst A is inert in the test, unlike that of catalyst B.

Both of these catalysts are tested in a fixed bed traversed unit. The catalyst volume used is 1000 cm3
The operating conditions are as follows:
- total pressure: 100 bar
- space velocity: 1 1 of charge / liter of catalyst /
hour
- H2 / charge: 1000 m3 / m3
- Presulfuration of the catalyst with a gaseous mixture
H2 + H2S (3%) at 350 C for 6 hours under pressure
atmospheric.

The feed used is deasphalted oil extracted from Venezuelan crude oil from Boscan (Boscan DAO), whose characteristics are as follows:
density at 20 C: 0.989 g / cm3
viscosity at 100 C: 161 mm 2 / s
- viscosity at 1500C: 25.3 mm2 / s
- carbon conradson: 10.3% weight
- insoluble in n heptane: 0.17% by weight
- insoluble in n-pentane: 1.7% by weight
- precipitated resins in
isopropanol: 10,% by weight
- total sulfur o 5.16% by weight
- nitrogen, total:. 3990 ppm
nickel: 47 ppm
- vanadium e 400 ppm
ASTM distillation
starting point: 2400C
50% point: 550 C
During the test the temperature is successively 3600C, 3800C, 400 C, 420 C, 3800C (so-called return temperature). During the evolution of temperatures, the catalyst is always the same.

 The results are shown in Table II.

TABLE II

<tb><SEP> CATALYST-A <SEP> CATALYST <SEP> B
<tb><SEP> Demeta- <SEP> Desulphu- <SEP> Conversion <SEP> Demeta- <SEP> Desulphu- <SEP> Invention <SEP>
<tb> lation <SEP> ration <SEP> of <SEP> resins <SEP> ration <SEP> ration <SEP> of <SEP> resins <SEP>
<tb><SEP> (%) <SEP> (%) <SEP> (%) <SEP> (%) <SEP> (%) <SEP> (%) <SEP>
360 360 <SEP> 46
<tb> 380 C <SEP> 96 <SEP> 61 <SEP> 56 <SEP> 89 <SEP> 58 <SEP> 41
<tb> 400 C <SEP> 99 <SEP> 77 <SEP> 91 <SEP> 94 <SEP> 74 <SEP> 85
<tb> 4200C <SEP> 99.5 <SEP> 81 <SEP> 96 <SEP> 97 <SEP> 78 <SEP> 94
<tb> 380 C <SEP> 72 <SEP> 31 <SEP> 48 <SEP> 53 <SEP> 27 <SEP> 29
<Tb>
It therefore clearly appears that the rate of demetallation and the rate of. Resin conversion is significantly higher with the catalyst having low n-heptane cracking activity, i.e., the less acidic.

Example 2
A catalyst C is prepared from the support B 1. This support B 1 is modified by addition of silica which is carried out by impregnation with a solution of ethyl silicate, carried out in a rotating drum. The mixture is left to mature for 4 hours in a confined atmosphere and the decomposition of the ethyl silicate is carried out by hydrolysis with water vapor: the alumina impregnated with ethyl silicate is placed for 72 hours in a saturator at 200 ° C. in the presence of liquid water.

Then calcination in air is carried out at 6000C for 2 hours.

The composition of the support thus obtained is
A1203 = 95 O7O SiO2 = 5%
From this support, catalyst C is prepared according to the technique described in Example I, its final composition is therefore
Al203 = 87 X weight
S02 = 4.5% by weight
MoO3 = 7% weight = = 1.5% weight
The cracking test of n-heptane is carried out on the support of this catalyst, the results obtained are shown in Table III.

TABLE III

<tb> Temperature <SEP> 470 C <SEP> 500 C <SEP>
<tb><SEP> activity of <SEP> cracking <SEP> 1.0 <SEP>. <SEP> 10.6 <SEP><SEP> 10.0 <SEP>. <SEP> 10-6
<tb> (mole / h / m2 <SEP> support)
<Tb>
Catalyst B of Example I and Catalyst C are tested in a fixed bed traversed unit. The volume of catalyst employed is 1000 cm 3. The operating conditions are as follows
- total pressure: 120 bar
- space velocity: 1 l load / l of cat / hour
- H2 / load: 1000 m3 / m3 TPN
- temperature: 380 C
- presulfuration identical to that described in
example 1
The load used is a Boscan (Venezuela) crude diluted with 20% of its weight of gas oil. The characteristics of this load are as follows
- insoluble in n-heptane: 10.8% by weight
- resins (insoluble in
isopropanol after elimination
asphaltenes): 10.3% by weight
- sulfur: 4.5% by weight
nickel: 98 ppm by weight
vanadium: 1030 ppm by weight
The results obtained are shown in Table IV.

TABLE IV

<tb><SEP> CATALYST <SEP> B <SEP> CATALYST <SEP> C
<tb><SEP> Converting <SEP> of <SEP> Converting <SEP> of
<tb> Demetallation <SEP> insoluble <SEP> in <SEP> Demetallation <SEP> insoluble <SEP> in
<tb><SEP> nC7 <SEP> nC7
<tb><SEP> 80 <SEP>% <SEP> 73 <SEP> X <SEP> 87 <SEP>% <SEP> 82 <SEP>% <SEP>
<Tb>
It therefore clearly appears that the catalyst whose support has a low n-heptane cracking activity, is much more active in demetallation and conversion of asphaltenes.

Claims (3)

claims 1. Use, in a reaction reaction of a hydrocarbon feedstock with hydrogen, of a supported catalyst containing at least one of vanadium, molybdenum, nickel, cobalt and / or iron tungsten, or at least one of the compounds of these metals, said catalyst being obtained by incorporating at least one compound of at least one of the above metals into a carrier which is inert with respect to the test for cracking heptane. 2. The use according to claim 1, wherein the hydrocarbon feedstock is a crude oil or a residual feedstock of hydrocarbons containing metals, asphaltenes and / or resins. 3. Use according to claim 1 or 2, wherein the temperature is 370 to 4700C, the pressure of 50 to 200 bar, the space velocity of 0.2 to 5 volumes per volume of catalyst per hour and the hydrogen gas ratio on hydrocarbon liquid charge of 200 to 5000 vol / vol.