FR3075070A1 - COMPARTMENTIZED BIN REAGENT AND HYDROCONVERSION PROCESS FOR HEAVY PETROLEUM LOADS - Google Patents

Abstract

 The subject of the invention is therefore a hydroconversion reactor for a liquid hydrocarbon feedstock comprising:  - a reactor shell (1),  a plurality of hydroconversion zones of different catalytic activity (Cn) delimited by horizontal internal walls (6) extending over the entire internal diameter of said reactor shell, each hydroconversion zone comprising a bubbling bed of catalyst,  - A device for withdrawing and injecting catalyst from one hydroconversion zone to another, consisting of a catalyst distribution box (10) connected to at least two hydroconversion zones by rods (7) comprising means for controlling the circulation of the catalyst between the different hydroconversion zones by the rods (7),  the horizontal internal walls (6) preventing the transfer of catalyst from one zone to another of the reactor, but allowing the passage of fluids.  Another subject of the invention is, according to another aspect, a process for catalytic hydroconversion of a liquid charge of hydrocarbons using such a reactor.

Description

The present invention relates to the field of hydroconversion of heavy carbonaceous feedstocks (for example an oil residue, derivatives derived from biomass, from coal) into lighter products which can be used as fuels or raw materials for petrochemicals. More particularly, the subject of the invention is a reactor and a process for catalytic conversion of hydrocarbons, in particular a process and an apparatus for catalytic hydroconversion of heavy petroleum feeds using bubbling beds.

The processes for hydroconversion of heavy hydrocarbon charges in a bubbling bed using a catalyst are well known to those skilled in the art. In these processes, the catalyst bed is in a dispersed and / or expanded form, the dispersion or expansion being caused by the bottom-up circulation of the liquid hydrocarbon charge and hydrogen or gas containing hydrogen. We speak of a bubbling bed or a fluidized bed. Examples of such processes include the H-Oil process, licensed by the company Axens, described for example in US patents 4,521,295 or US 4,495,060 or US 4,457,831, or the LC-Fining technology licensed by Chevron-Lummus -Global, widely described in the literature.

The hydrocarbon conversion catalysts used in these processes are deactivated mainly by deposition of metals, such as vanadium sulfide and nickel sulfide, and by coke deposition. Thus, in the processes of hydroconversion of heavy charges of hydrocarbons in bubbling bed, the catalyst must be periodically withdrawn from the reactor and replaced. Depending on the charge treated, conventional bubbling bed reactors operate with catalyst renewal rates (Crr) ranging from 0.01 to 8% by weight of the total mass of catalyst contained in the reactor (based on the mass of fresh catalyst). When the hydroconversion process contains several reactors in series, the catalyst renewal rates may be different in the different reactors.

The catalyst renewal compensates for the loss of activity mainly due to the deposition of metals and coke on the catalyst. In the processes for hydrotreating heavy hydrocarbon charges in a bubbling bed, the catalyst is therefore periodically withdrawn from the reactor and replaced. However, the withdrawn catalyst consists of a mixture of very strongly deactivated catalyst, moderately deactivated catalyst and almost new catalyst, so that the use of the catalyst in boiling bed hydrotreatment reactors is not optimized. More specifically, the periodic renewal of part of the catalyst contained in the reactor leads to a population with an age distribution whose shape depends on the rate of renewal of the catalyst (Crr). Figure 1 shows the age distribution of the catalyst grains in the bubbling bed reactor for a daily catalyst replacement rate of 2.5% relative to the total weight of catalyst in the reactor, which corresponds to a residence time. using the catalyst in the 40 day reactor. Thus, the average age of the catalyst in this configuration is also 40 days, but the age distribution is very wide, more than 36% by weight of the catalyst having an age greater than 40 days and more than 13% by weight of the catalyst. more than twice the average age, 80 days.

Sorting the catalyst particles according to their degree of deactivation is a difficult operation. In order to respond to this problem, it has been proposed in the prior art to use a series of staggered bubbling beds. The fresh catalyst is introduced into the upper stage of the reactor, preferably after a preliminary sulphurization, while the stages situated below contain a catalyst all the more deactivated as it is on a stage lower. Periodically, the catalyst from a stage n is allowed to descend to the stage n - 1 immediately below, while the less used catalyst from the upper stage η + 1 passes to stage n, and this for all of the floors. The catalyst of the last stage, at the bottom of the reactor, is discharged while fresh catalyst, preferably previously sulfurized, is introduced on the first stage at the top of the reactor. This improves the rate of use of a catalyst before discharge from the reactor. In addition, the fractionation of the reactor into a series of catalytic beds improves the efficiency of the reactor. The main problem encountered in this type of reactor relates to the transfer of the catalyst from one stage to the next stage situated below. It was first proposed to let the catalyst descend gradually through all the stages, but this has the major drawback of mixing, at each stage, of the relatively more active catalyst of stage n with relatively less active catalyst of the 'stage n - 1, hence a relatively poor use of the catalyst.

The patent FR2460990 has for example proposed to optimize the transfer of the catalyst between the different stages of a bubbling bed reactor compartmentalized by horizontal grids.

In this document, the meshes of the horizontal grids have a smaller diameter than that of the catalyst particles to allow the passage of the fluid (charge and hydrogen) from one compartment to another in the upward direction. The horizontal grids have open areas below which fluid distribution boxes are placed which allow the passage of the catalyst from an upper compartment to a lower compartment to be controlled. However, in this type of installation, it is necessary to interrupt the upward flow of liquids to allow the catalyst to descend from stage n to stage n-1. The conversion of hydrocarbons must therefore be periodically interrupted to allow this transfer of catalyst. This system is therefore complex and penalizing for production. It is also difficult with this type of installation to have a homogeneous distribution of the catalyst after it has passed from one compartment to the other. In addition, it is not possible to control the quantity of catalyst transferred from one stage to another of the reactor: it is the totality of the catalyst present on a stage which is transferred to the lower stage of the reactor, and c 'is therefore a large amount of spent catalyst which is drawn off at the bottom of the reactor, which can therefore always contain a significant proportion of catalyst still active.

There remains a need to further reduce catalyst consumption by more selective withdrawal of the most spent catalyst on the one hand, and to maximize the residence time of the most active catalyst in the reactor.

The present invention proposes a solution to this problem by means of a reactor and of a process making it possible to extract only the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded into the reactor, from the compartment having the lowest average catalytic activity, and consequently limiting as much as possible the loss of the most active catalyst.

It is indeed the merit of the Applicant to have demonstrated that by subdividing the bubbling bed reactor into several compartments so as to create zones in the reactor having different average catalytic activities, and extracting only the equivalent of With the addition of catalyst from the compartment having the lowest average catalytic activity, it was possible to optimize the use of the catalyst and thus reduce the catalyst replacement rate or increase the performance of the reactor.

The object of the invention is therefore, according to a first aspect, a hydroconversion reactor of a liquid hydrocarbon charge comprising:

- a reactor shell (1),

a plurality of hydroconversion zones of different catalytic activities (Cn) delimited by horizontal internal walls (6) extending over the entire internal diameter of said reactor shell, each hydroconversion zone comprising a bubbling bed of catalyst,

- A device for withdrawing and injecting catalyst from one hydroconversion zone to another, consisting of a catalyst distribution box (10) connected to the various hydroconversion zones by rods (7) comprising means controlling the circulation of the catalyst between the various hydroconversion zones by the rods (7), the horizontal internal walls (6) preventing the transfer of catalyst from one zone to another of the reactor, but allowing the passage of fluids.

Another subject of the invention is, according to another aspect, a process for catalytic hydroconversion of a liquid charge of hydrocarbons by means of hydrogen consisting in passing the liquid charge of hydrocarbons and a stream of hydrogen or d 'a gas containing hydrogen from bottom to top through at least one hydroconversion reactor as described above, in which the equivalent of a make-up of catalyst, that is to say between 0, 01% and 8% of the total weight of the catalyst loaded into the reactor, is withdrawn from a hydroconversion zone and is injected into another hydroconversion zone having a lower catalytic activity.

The reactor and the process according to the invention can also make it possible to increase the average catalytic activity in the compartmentalized reactor while maintaining the consumption of catalyst equivalent to a conventional bubbling bed reactor, not comprising a plurality of hydroconversion zones d 'different catalytic activities. It is possible, for example, to increase the level of catalytic activity, such as the hydrogenating, crunching or desulfurizing activity, and therefore the level of transformations of the treated charges by slightly increasing the temperature or the hourly volume speed (WH), at iso catalyst renewal (Crr). In addition, an improved catalytic activity makes it possible to reduce the formation of sediments in the reactor, and therefore either to improve its operability or to increase the severity of the process.

The introduction of the principle of compartmentalization of the reactor described above in fact leads to modifying the age distribution of the catalyst. Figure 2 gives, for a Crr of 2.5%, the age distributions in a reactor when this reactor is divided into 4 compartments. In the reactor, the average residence time of the catalyst remains equal to 40 days. However, as the catalyst withdrawal removes older catalyst, the average age of the catalyst is only 25 days. In addition, the age distribution is also much less wide, less than 20% by weight of the catalyst having an age greater than 40 days and less than 2% by weight of the catalyst having an age greater than twice the average age, ie 80 days. Therefore, this age distribution of the catalyst leads to a more active catalyst compared to a catalyst used in a reactor with a single compartment. Figure 3 compares the age distributions of the catalyst population in a non-compartmentalized bubbling-bed reactor and in a bubbling-bed reactor divided into 2, 3 and 4 zones with overall withdrawal and make-up of fresh catalyst of 2.5% compared to the total weight of the catalyst in the reactor.

Description of the figures

FIG. 1 represents the age distribution of the catalyst population in a bubbling bed reactor with a withdrawal and daily intake of fresh catalyst of 2.5% compared to the initial inventory of fresh catalyst.

FIG. 2 represents the age distribution of the catalyst population in a bubbling bed reactor compartmentalized into 4 zones with overall withdrawal and top-up of fresh catalyst of 2.5% compared to the initial inventory of fresh catalyst.

FIG. 3 represents a comparison of the distributions of the ages of the population of catalyst in a non-compartmentalized bubbling bed reactor and in a bubbling bed reactor divided into 2, 3 and 4 zones with overall withdrawal and make-up of fresh catalyst of 2, 5% compared to the initial fresh catalyst inventory.

FIG. 4 illustrates a bubbling bed reactor according to the invention, with 4 hydroconversion zones with different catalytic activity.

detailed description

The hydroconversion reactor used in the context of the present invention is described in more detail with reference to FIG. 4.

The reactor comprises a reactor shell (1), preferably having a cylindrical wall.

It includes a plurality of hydroconversion zones with different catalytic activities (Cl, C2, C3, C4). In particular, the reactor comprises at least two hydroconversion zones with different catalytic activities, preferably at least three zones, and more preferably four or more zones.

According to a particular embodiment, the hydroconversion zone exhibiting the highest catalytic activity is situated at the highest level in the reactor, while the zones situated below exhibit an activity which is all the lower as they are found at a lower level in the reactor.

According to another particular embodiment, the hydroconversion zone having the weakest catalytic activity is situated at the highest level in the reactor, while the zones situated below exhibit an activity which is all the stronger as they are at a lower level in the reactor.

The distribution of the activity of the catalyst in the various hydroconversion zones of the reactor is determined by the injections and withdrawals of catalyst carried out according to the invention.

According to a preferred embodiment, the hydroconversion zones all have substantially the same volume.

The different zones are delimited by horizontal internal walls (6) extending over the entire inside diameter of the reactor casing. These horizontal internal walls prevent the passage of the catalyst from one zone to another of the reactor, but allow the passage of fluids, in particular the liquid charge of hydrocarbons and the stream of hydrogen or of a gas containing hydrogen.

The horizontal internal walls (6) are thus preferably perforated, and can for example consist of a grid. This type of wall is similar to the charge distribution plates usually used in bubbling bed reactors.

The horizontal compartmentalisation of the hydroconversion zones implemented in the reactor according to the present application allows a particularly homogeneous radial distribution by limiting, or even avoiding, the preferred paths.

Each hydroconversion zone includes a bubbling bed of catalyst. According to a preferred embodiment, the different hydroconversion zones comprise the same catalyst with different activity depending on the deactivation level.

The hydroconversion catalyst used in the hydroconversion process according to the invention preferably contains one or more elements from groups 4 to 12 of the periodic table of the elements, which can be deposited on a support or not supported. It is advantageously possible to use a catalyst comprising a support, preferably amorphous, such as silica, alumina, silica-alumina, titanium dioxide or combinations of these structures, and very preferably of the alumina, and at least one group VIII metal chosen from nickel and cobalt and preferably nickel, said group VIII element being preferably used in combination with at least one metal from group VIB chosen from molybdenum and tungsten and preferably, the metal of group VIB is molybdenum.

Advantageously according to the invention, the hydroconversion catalyst used in the various catalytic zones is a catalyst comprising an alumina support and at least one metal from group VIII chosen from nickel and cobalt, preferably nickel, said element of the group VIII being used in combination with at least one metal from group VIB chosen from molybdenum and tungsten, preferably the metal from group VIB is molybdenum. Preferably, the hydroconversion catalyst comprises nickel as part of group VIII and molybdenum as part of group VIB.

The nickel content is advantageously between 0.5 to 10% expressed by weight of nickel oxide (NiO) and preferably between 1 to 6% by weight, and the molybdenum content is advantageously between 1 and 30% expressed in weight of molybdenum trioxide (ΜοΟβ) and preferably between 4 and 20% by weight.

This catalyst is advantageously used in the form of extrudates or beads, the size of which is preferably between 0.5 and 4 mm. Thus, the catalyst is used in an expanded bed, called a bubbling bed. One can also refer to the expression expanded catalyst to designate such a catalyst used in an expanded bed.

In addition to this type of catalyst, another type of catalyst known as slurry according to English terminology or called as entrained catalyst or even dispersed catalyst can be used in the process according to the invention, in admixture with the expanded catalyst. Said slurry catalyst has a particle size and a density adapted to its training. For example, the slurry catalyst has a size less than 500 μπι. By entrainment of the dispersed catalyst is meant its circulation in the catalytic zones by the liquid flows, said dispersed catalyst circulating with the charge in said catalytic zones, and being either entrained outside the reactor by the liquid, or withdrawn from said zones at by means of a device for withdrawing and injecting catalyst described below.

The hydroconversion reactor according to the invention further comprises a device for withdrawing and injecting catalyst from one hydroconversion zone to another.

The catalyst withdrawal and injection device consists of a catalyst distribution box (10) connected to at least two hydroconversion zones by rods (7) allowing the extraction of catalyst from a catalytic zone to the distribution box, and the catalyst discharge from the distribution box to one of the catalytic zones.

According to a preferred embodiment, the catalyst distribution box (10) is connected to the various hydroconversion zones present in the reactor.

These rods (7) comprise means for controlling the circulation of the catalyst by the rods (7), between the various hydroconversion zones. These control means preferably include valves (8). They may also include other elements such as pumps, storage bins, etc.

Preferably, the means for controlling the circulation of the catalyst between the different hydroconversion zones by the rods (7) comprise valves (8), each rod (7) comprising a valve (8).

The device for withdrawing and injecting catalyst can also comprise a line for entering and leaving the catalyst, or alternatively, a line for entering the catalyst (11) and a line for leaving the catalyst (12) allowing the addition of catalyst and extraction of spent catalyst.

The catalyst is preferably conveyed during injection and extraction by the withdrawal and injection device with a carrier fluid. The carrier fluid during withdrawal is the liquid present in the reactor. During the injection, the carrier fluid can be the same fluid or a vacuum distillate (VGO), a heavy vacuum distillate (HVGO), an atmospheric distillate (AGO), or any other hydrocarbon-based liquid charge.

The spent catalyst can then be sent to a regeneration zone in which the carbon and the sulfur which it contains are removed. It is also possible to send the spent catalyst withdrawn from the reactor to a rejuvenation zone in which most of the deposited metals are removed, before sending the spent and rejuvenated catalyst to a regeneration area in which the carbon is removed and the sulfur it contains.

The regenerated or rejuvenated catalyst can then be reintroduced into the reactor according to the invention, optionally in combination with fresh catalyst, via the catalyst inlet line (11).

The reactor according to the invention may also include a charge injection chamber (14), into which the liquid charge of hydrocarbons and hydrogen are introduced through a supply pipe (3) located at the bottom of the reactor (1). Hydrogen can be introduced as a stream of pure hydrogen or as a hydrogen-containing gas.

The load distribution plate (6) located above the injection chamber (14) allows the load to be distributed homogeneously over the entire section of the reactor.

The feedstock treated in the process according to the invention is a liquid feedstock of hydrocarbons, such as, for example, crude oil. It is preferably a heavy load of hydrocarbons (called residue). Advantageously, this feedstock is a feedstock comprising fractions of hydrocarbons produced in the refinery. The fillers according to the invention include fillers containing hydrocarbon fractions of which at least 50% by weight have a boiling temperature above 300 ° C., atmospheric residues and / or vacuum residues, atmospheric residues and / or vacuum from hydrotreating, hydrocracking and / or hydroconversion, vacuum distillates from primary fractionation, called straight run according to English terminology, or refined, cuts coming from a unit of cracking like FCC, hydrocracking, coking or visbreaking, aromatic cuts extracted from a lubricant production unit, deasphalted oils from a deasphalting unit, asphalts from a deasphalting unit or similar hydrocarbon feedstocks, or a combination of these fresh feedstocks and / or refined effluents. Said feed can also contain a residual fraction resulting from the direct liquefaction of coal (an atmospheric residue and / or a vacuum residue resulting for example from the H-Coal ™ process), a vacuum distillate resulting from the direct liquefaction of coal, such as for example the H-Coal ™ process, residues of pyrolysis of coal or shale oils, or else a residual fraction resulting from the direct liquefaction of lignocellulosic biomass alone or in mixture with coal and / or a fresh petroleum fraction and / or refined. Preferably, the feedstock treated in the context of the present invention consists of hydrocarbon fractions resulting from a crude oil or from the atmospheric distillation of a crude oil or from the vacuum distillation of a crude oil, said feeds containing at least 50% by weight of a fraction having an initial boiling temperature of at least 300 ° C, preferably at least 350 ° C and preferably at least 375 ° C and more preferably vacuum residues having a boiling temperature of at least 450 ° C, preferably at least 500 ° C and more preferably at least 540 ° C.

Generally, the feeds treated in the process according to the invention may contain impurities, such as metals, sulfur, nitrogen, Conradson carbon and compounds insoluble in heptane, also called C7 asphaltenes. These fillers are in fact generally rich in impurities with metal contents greater than 20 ppm, preferably greater than 100 ppm. The sulfur content is greater than 0.1% by weight, preferably greater than 1% by weight, and preferably greater than 2% by weight. The level of C7 asphaltenes is at least 0.1% by weight and is preferably greater than 3% by weight. Asphaltenes C7 are compounds known to inhibit the conversion of residual cuts, both by their ability to form heavy hydrocarbon residues, commonly called coke, and by their tendency to produce sediments which greatly limit the operability of the units of hydrotreating and hydroconversion. The Conradson carbon content is greater than 0.5% by weight, and preferably at least 5% by weight. The Conradson carbon content is defined by standard ASTM D 482 and represents for a person skilled in the art a well-known evaluation of the quantity of carbon residues produced after pyrolysis under standard conditions of temperature and pressure.

The liquid hydrocarbon charge and hydrogen are introduced into the reactor (1) via line (3). The reactor can also comprise an internal or external recycling line (2) connected to a boiling pump (4) which can be internal or external to the reactor, which ensures a supply flow rate of a recycled cup in the reactor ( 1) through the conduit (15). The pump (4) is connected to the feed reinjection pipe (15) at the bottom of the reactor. If the recycling is internal to the reactor, the conduit (15) is located inside the reactor, if the recycling is external, the conduit (15) is located outside the reactor, as illustrated in FIG. 4.

The total flow of different feeds is sufficient to keep the catalytic bed in boiling. In the configuration with a boiling pump, the pump (4) makes it possible in particular to maintain the catalyst in a bubbling bed by continuous recycling of at least part of a liquid fraction advantageously drawn off at the head of the reactor and reinjected at the bottom of the reactor. through the conduit (15).

When recycling is carried out, the liquid hydrocarbon charge and the hydrogen introduced through the line (3) are mixed, in the injection chamber (14), with the recycled charge introduced through the line (15).

The reactor according to the invention may include an outlet conduit (9) for the treated charge (hydroconversion effluent).

Part of the treated charge leaves the reactor via the conduit (9) while the rest of the charge is returned to the recycling conduit, which can be internal (2) or external.

In addition to the hydroconversion reactor described above, the invention also relates to a hydroconversion process using said reactor.

In particular, the subject of the present invention is a process for catalytic hydroconversion of a liquid charge of hydrocarbons by means of hydrogen consisting in passing the liquid charge of hydrocarbons and a stream of hydrogen or of a gas containing hydrogen through at least one hydroconversion reactor comprising:

- a reactor shell (1),

a plurality of hydroconversion zones of different catalytic activities (Cn) delimited by horizontal internal walls (6) extending over the entire internal diameter of said reactor shell, each hydroconversion zone comprising a bubbling bed of catalyst,

- A device for withdrawing and injecting catalyst from one hydroconversion zone to another, consisting of a catalyst distribution box (10) connected to at least two hydroconversion zones by rods (7) comprising means for controlling the circulation of the catalyst between the various hydroconversion zones by the rods (7), the horizontal internal walls (6) preventing the transfer of catalyst from one zone to another of the reactor, but allowing the passage of the fluids, and in which the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded in the reactor, is withdrawn from a hydroconversion zone and is injected into another hydroconversion zone having a lower catalytic activity.

The hydroconversion reactor, the feedstock and the catalyst used in the process according to the invention are as described above. According to a preferred embodiment, the method according to the invention implements several reactors as described above, in series, preferably two reactors in series, and more preferably three reactors in series.

When the process uses several reactors according to the invention in series, the rate of replacement of the catalyst in each reactor can be the same. Preferably, the catalyst replacement rate is higher in the first reactor than in the second reactor due to the difference in the amount of impurities introduced into each reactor. For the same reason, for each of the reactors in series, the rate of replacement of the catalyst is preferably lower than that of the preceding reactor and higher than that of the following reactor.

In the context of the process according to the invention, the device for withdrawing and injecting catalyst preferably comprises an inlet and outlet line for the catalyst, or alternatively, an inlet line for fresh and / or regenerated catalyst and / or rejuvenated (11) and an outlet line for the spent catalyst (12).

In a hydroconversion zone, the catalyst is replaced by withdrawing part of the present catalyst and by injecting fresh and / or regenerated and / or rejuvenated catalyst.

In one embodiment, the fresh and / or regenerated and / or rejuvenated catalyst is first added to a hydroconversion zone before the withdrawal of catalyst has taken place.

In a preferred embodiment, part of the catalyst present in the zone is first drawn off, typically between 0.01% and 8% of the total weight of the catalyst loaded into the reactor, before adding fresh catalyst and / or regenerated and / or rejuvenated.

Thus, the withdrawal of the catalyst add-on from a hydroconversion zone and its injection into another hydroconversion zone having a lower catalytic activity, can comprise the steps below, the means for controlling the circulation of the catalyst between the different hydroconversion zones by the rods (7) comprising valves (8), and each rod (7) comprising a valve (8):

i. the opening of the valve (8.C _n ) controlling the circulation of the catalyst through the rod (7) present in the zone (C _n ) of lower catalytic activity so as to allow the connection between the zone (C _n ) and the catalyst distribution box (10), the other valves (8) remaining closed, ii. the withdrawal of the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded in the reactor, from zone (C _n ) towards the distribution box (10), iii. closing the valve (8.C _n ), iv. the extraction, by the outlet line of the spent catalyst (12), of the withdrawn catalyst,

v. the opening of the valve (8.C _{n +} i) controlling the circulation of the catalyst through the rod (7) present in the zone (C _{n +} i) of catalytic activity greater than the zone (C _n ) so as to allow the connection between the zone (C _{n +} i) and the catalyst distribution box (10), the other valves (8) remaining closed, vi. withdrawing the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded in the reactor, from the zone (C _{n +} i) towards the distribution box (10), vii. closing the valve (8.C _{n +} i) and opening the valve (8.C _n ), viii. injecting the extra catalyst contained in the distribution box (10) into the zone (C _n ) of lower catalytic activity, and closing the valve (8. C _n ), ix. optionally, repeating steps v. to viii. to carry out the withdrawal and the addition of catalyst in each of the hydroconversion zones of the reactor,

x. the opening of the valve (8.C _{n + x} ) controlling the circulation of the catalyst through the rod (7) present in the zone (C _{n + X} ) of highest catalytic activity, xi. the injection, in the zone (C _{n + X} ), of the equivalent of an addition of fresh and / or regenerated and / or rejuvenated catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded into the reactor contained in the distribution box (10) via the fresh and / or regenerated and / or rejuvenated catalyst inlet line (11).

According to a particular embodiment, the same amount of catalyst add-on is drawn off and injected into each hydroconversion zone of the reactor.

According to a preferred embodiment, the addition of catalyst injected in step xi. is a fresh catalyst.

With more specific reference to the particular embodiment illustrated in FIG. 4, in which the reactor comprises four catalytic zones of different activities, where the catalytic zone exhibiting the highest catalytic activity is situated at the highest level in the reactor, while the zones situated below have an activity which is all the lower as they are at a lower level in the reactor, the withdrawal and the addition of catalyst are carried out according to the following stages:

i. opening the valve (8.C4) to allow connection between the compartment (C4) having the lowest catalytic activity and the catalyst distribution box (10). The other valves (8.Cn) remain closed, ii. withdrawing part of the catalyst from the compartment (C4) in the catalyst distribution box (10), iii. closing the valve (8.C4) to isolate the compartment (C4), iv. extracting the catalyst contained in the box (10) to a spent catalyst storage tank (not shown),

v. opening the valve (8.C3) to allow connection between the compartment (C3) and the catalyst distribution box (10), vi. the withdrawal of part of the catalyst from compartment C3 in the box (10).

vii. closing the valve (8.C3) and opening the valve (8.C4).

viii. injecting the catalyst withdrawn from compartment C3, contained in the catalyst box (10), into the compartment (C4) and closing the valve (8.C4).

The steps in vi. to viii. are repeated to draw off and add catalyst from compartments (C2) and (C3), then (Cl) and (C2).

At the end of this process of transferring catalyst from one compartment to another, the compartment (Cl) is with a catalyst deficit equivalent to the amount of catalyst withdrawn from the compartment (C4). To compensate for this deficit, the fresh and / or regenerated and / or rejuvenated catalyst is added to the compartment (Cl).

According to a preferred embodiment, the addition of catalyst injected into the compartment (Cl) is a fresh catalyst.

It does not depart from the scope of the invention if the hydroconversion zone from which the add-on catalyst is withdrawn and the hydroconversion zone having a lower catalytic activity into which the withdrawn catalyst is injected are not adjacent zones . For example, in the case of a reactor comprising four zones like that shown in FIG. 4, a withdrawal can be carried out in zone C2, and the injection of the catalyst withdrawn from zone C2 can be carried out in zone C4. The sequence can be continued by withdrawing from the zone C3 the addition of catalyst, and by injecting this supplement originating from C3 in the zone C2, then by withdrawing from the zone C1 the supplement of catalyst and by injecting this supplement originating from Cl in zone C3. Any other order may be established. The order of the zones adopted in the process of transferring catalyst from one zone to another determines the distribution of the activity of the catalyst in the different hydroconversion zones.

Hydroconversion is carried out under conditions well known to those skilled in the art. In particular, the method according to the invention can be operated at an absolute pressure of between 2 and 35 MPa, preferably between 5 and 25 MPa and preferably, between 6 and 20 MPa, at a temperature between 300 and 550 ° C and preferably between 350 and 500 ° C and preferably between 370 and 450 ° C, and more preferably between 390 and 430 ° C. The hourly space velocity (WH) relative to the volume of each reactor is between 0.05 h ' ¹ and 10 h' ¹ , preferably between 0.1 h ' ¹ and 5 h' ¹ and preferably between 0, 15 h ^-1 and 2 h ^-1.

The quantity of hydrogen mixed with the feed is preferably between 50 and 5000 3 3 normal cubic meters (Nm) per cubic meter (m) of liquid feed taken under standard conditions of temperature and pressure, preferably between 100 and 2000 Nm / m and from

3 very preferably between 200 and 1000 Nm / m.

At the end of the hydroconversion process according to the invention, the charge treated by hydroconversion is recovered at the outlet of the reactor by the conduit (9).

The following examples illustrate the invention without limiting its scope.

EXAMPLES

Charge

The heavy load is a vacuum residue (RSV) from a Ural crude oil, the main characteristics of which are presented in Table 1 below.

Table 1: Composition of the load

Charge RSV Urals 540 ° C + content %weight 83 Density 1.00 Viscosity at 100 ° C cSt 533 Nickel + Vanadium ppm 233 Sulfur %weight 2.98 Nitrogen ppm 4600 Conradson carbon %weight 16.4

This heavy load RSV is the same fresh load for the different examples.

Example I: Comparative example.

In this example, the state of the art is illustrated in a process diagram with a bubbling bed reactor which is not compartmentalized. The fresh charge of Table 1 is sent in full and in the presence of hydrogen in the hydroconversion reactor operating in a bubbling bed with rising current of liquid and gas. The reactor contains a NiMo / alumina hydroconversion catalyst having an NiO content of 4% by weight and a content of

ΜοΟβ of 10% by weight, the percentages being expressed relative to the total mass of the catalyst. The conditions applied in the hydroconversion reactor are presented in Table 2.

Table 2: Operating conditions of the hydroconversion stage in the case of a non-compartmentalized reactor

WH reactor h ' ¹ 0.23 Total pressure MPa 16 Temperature ° C 425 Amount of hydrogen Nm ³ / m ³ 650 Total catalyst inventory tons 158 Overall catalyst renewal rate %weight 2.5 Daily catalyst replacement tons / day 3.9

These operating conditions make it possible to obtain a liquid effluent with a reduced content of Conradson carbon (CCR), of metals, of nitrogen and of sulfur. The conversion of the 540 ° C + fraction at the outlet of the hydroconversion step is 70% by weight. Table 3 gives the different performances at the output of the reaction section.

Table 3: Catalytic performance of the hydroconversion stage in the case of a non-compartmentalized reactor

Metal conversion rate (HDM) wt% 92 Sulfur conversion rate (HDS) wt% 86 Nitrogen conversion rate (HDN) wt% 42 Conradson Carbon Conversion Rate (HDCCR) wt% 66

Example II: Example according to the invention with economy of catalyst.

In this example, the invention is illustrated in a process diagram with a bubbling bed reactor which is compartmentalized into 4 compartments. The catalyst renewal rate is adjusted so as to obtain the same catalytic performance (conversion rate of metals, sulfur, nitrogen and Conradson carbon) as those obtained in Example 1. The other operating conditions are not not changed. The fresh charge of Table 1 is sent in full and in the presence of hydrogen to the compartmentalized hydroconversion reactor operating in a bubbling bed with rising current of liquid and gas. The reactor contains a NiMo / alumina hydroconversion catalyst having an NiO content of 4% by weight and an ΜοΟβ content of 10% by weight, the percentages being expressed relative to the total mass of the catalyst. The conditions applied in this hydroconversion reactor are presented in Table 4.

Table 4: Operating conditions of the hydroconversion stage aimed at saving catalyst (case of reactor compartmentalized into 4 compartments)

WH reactor h 0.23 Total pressure MPa 16 Temperature ° C 425 Amount of hydrogen Nm ³ / m ³ 650 Total catalyst inventory tons 158 Overall catalyst renewal rate %weight 1.9 Daily catalyst replacement tons / day 3.0

These operating conditions make it possible to obtain a liquid effluent with a reduced content of Conradson carbon (CCR), of metals, of nitrogen and of sulfur. The conversion of the 540 ° C + fraction at the outlet of the hydroconversion stage is 70% by weight. Table 5 gives the different performances at the output of the reaction section. They are identical to those of Example I, apart from the catalyst replacement rate (and the daily catalyst replacement) which is significantly reduced.

Table 5: Catalytic performances of the hydroconversion stage in the case of a compartmentalized reactor and aiming at a catalyst economy

Metal conversion rate (HDM) wt% 92 = Sulfur conversion rate (HDS) wt% 86 = Nitrogen conversion rate (HDN) wt% 42 = Conradson Carbon Conversion Rate (HDCCR) wt% 66 =

To maintain the catalytic performance obtained in Example 1 with a non-compartmentalized reactor, the process according to the invention is operated with an overall catalyst renewal rate of 1.9% instead of 2.5% in Example 1 (-24% relative), which corresponds to a gain in catalyst consumption of almost 1 ton per day. By using significantly less catalyst, the same catalytic performance is obtained, thanks to the presence of the compartments which allow a selective withdrawal of older catalyst.

Example III: Configuration with two reactors in series

Two reactors Ri and R ₂ identical to those described in Examples I and II, are operated in series under the same conditions and with the same load as in Examples I and II.

The overall catalyst renewal rate of the reactor Ri has been set at 2.5%, and that of the reactor R ₂ at 1.25% for the series reactors according to the prior art, not comprising hydroconversion zones d 'different catalytic activity.

To obtain similar catalytic performances, the overall catalyst renewal rate of the reactor Ri compartmentalized according to the invention in 4 zones was lowered to 1.85%, and that of the reactor R ₂ compartmentalized in 4 zones to 0.97%.

Table 6 presents an example indicating the economy of catalyst which can be made following the compartmentalization of each reactor into four zones. The catalyst gain on the two reactors is therefore 1.5 tonnes / day.

Table 6: Catalyst savings compared to the conventional configuration.

Classic case Case with 4 compartments Ri r ₂ Ri + R ₂ Ri r ₂ Ri + R ₂ Crr (%) 2.5 1.25 - 1.85 0.97 - Catalyst consumption (tonnes / day) 3.9 2.0 5.9 2.9 1.5 4.4 Catalyst gain (%) - - - 26 22 24 Catalyst gain (tonnes / day) - - - 1.0 0.5 1.5

Example IV: Example according to the invention while maintaining the same catalyst replacement rate to maximize the catalytic activity in the reactor

In this example, the invention is illustrated in a process diagram with a bubbling bed reactor which is compartmentalized into 4 compartments. The fresh charge of Table 1 is sent in full and in the presence of hydrogen to the compartmentalized hydroconversion reactor operating in a bubbling bed with rising current of liquid and gas. The reactor contains a NiMo / alumina hydroconversion catalyst having an NiO content of 4% by weight and an ΜοΟβ content of 10% by weight, the percentages being expressed relative to the total mass of the catalyst. The conditions applied in this hydroconversion reactor are presented in Table 7.

Table 7: Operating conditions of the hydroconversion stage while maintaining the same catalyst replacement rate to maximize the catalytic activity in the reactor

WH reactor h ' ¹ 0.23 Total pressure MPa 16 Temperature ° C 425 Amount of hydrogen Nm ³ / m ³ 650 Total catalyst inventory tons 158 Overall catalyst renewal rate %weight 2.5 Daily catalyst replacement tons / day 3.9

These operating conditions make it possible to obtain a liquid effluent with a reduced carbon content.

Conradson (CCR), in metals, nitrogen and sulfur. The conversion of the 540 ° C + fraction at the outlet of the hydroconversion stage is 71% by weight. Table 8 gives the different performances at the output of the reaction section.

Table 8: Catalytic performance of the hydroconversion stage in the case of a compartmentalized reactor while maintaining the same catalyst replacement rate 10 to maximize the catalytic activity in the reactor

Metal conversion rate (HDM) wt% 93 +1 Sulfur conversion rate (HDS) wt% 87 +1 Nitrogen conversion rate (HDN) wt% 45 3 Conradson Carbon Conversion Rate (HDCCR) wt% 68 2

This second way of enhancing the compartmentalization of the reactor proposed in the present invention therefore consists in keeping a catalyst consumption equal to that of the basic case (3.9 tonnes per day) and thus operating the reactor with a less aged catalyst, therefore less disabled and therefore having a higher activity. It is therefore a question of improving the performance 15 of the unit by improving the quality of the products as well as the operability of the unit.

Example V: Configuration with two reactors in series

Two reactors Ri and R ₂ identical to those described in Examples I and II, are operated in series under the same conditions and with the same load as in Examples I and II.

In both cases, the overall catalyst renewal rate of the reactor Ri was set at 2.5%, and that of the reactor R ₂ at 1.25% for the series reactors according to the prior art, not comprising hydroconversion zones of different catalytic activity.

Table 9 presents an example indicating the gain in catalytic activity which can be made following the compartmentalization of each reactor into four compartments.

Table 9: Example illustrating the gain on catalytic activity.

Ri r ₂ Crr (%) 2.5 1.25 Gain in catalytic activity (%) 19.9 21.4

⁽ * ⁾ : Compared to the case without compartments.

Claims (17)

1. Hydroconversion reactor of a liquid hydrocarbon charge comprising: - a reactor shell (1), - A plurality of hydroconversion zones of different catalytic activity (Cn) delimited by horizontal internal walls (6) extending over the entire inside diameter of said reactor shell, each hydroconversion zone comprising a bubbling bed of catalyst, - A device for withdrawing and injecting catalyst from one hydroconversion zone to another, consisting of a catalyst distribution box (10) connected to at least two hydroconversion zones by rods (7) comprising means for controlling the circulation of the catalyst between the different hydroconversion zones by the rods (7), the horizontal internal walls (6) preventing the transfer of catalyst from one zone to another of the reactor, but allowing the passage of the fluids. 2. Reactor according to claim 1, characterized in that the catalyst distribution box (10) is connected to the various hydroconversion zones. 3. Reactor according to any one of claims 1 or 2, characterized in that it comprises a charge injection chamber (14), in which the liquid charge of hydrocarbons and hydrogen are introduced at the bottom from the reactor (1) via a supply line (3) with a supply rate sufficient to keep the catalyst beds in boiling. 4. Reactor according to any one of claims 1 to 3, characterized in that it comprises an internal or external recycling line (2) connected to a boiling pump (4) which can be internal or external to the reactor, which ensures recycling of the charge reinjected at the bottom of the reactor through a pipe (15). 5. Reactor according to claim 4, characterized in that the liquid hydrocarbon charge and the hydrogen introduced through the line (3) are mixed, in the injection chamber (14), with the recycled charge introduced through the line (15). 6. Reactor according to any one of the preceding claims, characterized in that it comprises an outlet conduit (9) of the treated charge. 7. Reactor according to any one of the preceding claims, characterized in that the device for withdrawing and injecting catalyst comprises an inlet and outlet line for the catalyst, or alternatively, an inlet line for fresh catalyst, and / or regenerated and / or rejuvenated (11) and an outlet line for the spent catalyst (12). 8. Reactor according to any one of the preceding claims, characterized in that it comprises at least two hydroconversion zones with different catalytic activities, preferably at least three zones, and more preferably four or more zones. 9. Reactor according to any one of the preceding claims, characterized in that the reactor shell has a cylindrical wall. 10. Reactor according to any one of the preceding claims, characterized in that the different hydroconversion zones comprise the same catalyst with different activity depending on the deactivation level. 11. Reactor according to any one of the preceding claims, characterized in that the various hydroconversion zones further comprise a dispersed catalyst of the slurry type. 12. A method of catalytic hydroconversion of a liquid hydrocarbon charge by means of hydrogen consisting in passing the liquid charge of hydrocarbons and a stream of hydrogen or of a gas containing hydrogen through at least one hydroconversion reactor comprising: - a reactor shell (1), a plurality of hydroconversion zones of different catalytic activity (Cn) delimited by horizontal internal walls (6) extending over the entire internal diameter of said reactor shell, each hydroconversion zone comprising a bubbling bed of catalyst, - A device for withdrawing and injecting catalyst from one hydroconversion zone to another, consisting of a catalyst distribution box (10) connected to at least two hydroconversion zones by rods (7) comprising means for controlling the circulation of the catalyst between the various hydroconversion zones by the rods (7), the horizontal internal walls (6) preventing the transfer of catalyst from one zone to another of the reactor, but allowing the passage of the fluids, and in which the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded in the reactor, is withdrawn from a hydroconversion zone and is injected into another hydroconversion zone having a lower catalytic activity. 13. Method according to claim 12, characterized in that the device for withdrawing and injecting catalyst comprises an inlet and outlet line for the catalyst, or alternatively, an inlet line for fresh, and / or regenerated catalyst and / or rejuvenated (11) and an outlet line for the spent catalyst (12). 14. Method according to claim 13, characterized in that the means for controlling the circulation of the catalyst between the different hydroconversion zones by the rods (7) comprise valves (8), each rod (7) comprising a valve ( 8), and characterized in that the withdrawal of the catalyst add-up from a hydroconversion zone and its injection into another hydroconversion zone having a lower catalytic activity, comprises the following stages: i. the opening of the valve (8.C _n ) controlling the circulation of the catalyst through the rod (7) present in the zone (C _n ) of lower catalytic activity so as to allow the connection between the zone (C _n ) and the catalyst distribution box (10), the other valves (8) remaining closed, ii. the withdrawal of the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded in the reactor, from zone (C _n ) towards the distribution box (10), iii. closing the valve (8.C _n ), iv. the extraction, by the outlet line of the spent catalyst (12), of the withdrawn catalyst, v. the opening of the valve (8.C _{n +} i) controlling the circulation of the catalyst through the rod (7) present in the zone (C _{n +} i) of catalytic activity greater than the zone (C _n ) so as to allow the connection between the zone (C _{n +} i) and the catalyst distribution box (10), the other valves (8) remaining closed, vi. withdrawing the equivalent of a make-up of catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded in the reactor, from the zone (C _{n +} i) towards the distribution box (10), vii. closing the valve (8.C _{n +} i) and opening the valve (8.C _n ), viii. injecting the extra catalyst contained in the distribution box (10) into the zone (C _n ) of lower catalytic activity, and closing the valve (8. C _n ), ix. optionally, repeating steps v. to viii. to carry out the withdrawal and the addition of catalyst in each of the hydroconversion zones of the reactor, x. the opening of the valve (8.C _{n + x} ) controlling the circulation of the catalyst through the rod (7) present in the zone (C _{n + X} ) of highest catalytic activity, xi. the injection, in the zone (C _{n + X} ), of the equivalent of an addition of fresh and / or regenerated and / or rejuvenated catalyst, that is to say between 0.01% and 8% of the total weight of the catalyst loaded into the reactor contained in the distribution box (10) via the fresh and / or regenerated and / or rejuvenated catalyst inlet line (11). 15. Method according to any one of claims 12 to 14, characterized in that the same amount of catalyst add-on is injected and injected into each hydroconversion zone. 16. Method according to any one of claims 12 to 15, characterized in that the addition of catalyst injected in step xi. is a fresh catalyst. 17. Method according to any one of claims 12 to 16, characterized in that the hydroconversion reactor is according to any one of claims 2 to 11. 1/3 Crr = 2.5% weight