EP0819752B1 - Process and apparatus for the conversion of a hydrocarbon feedstock using two hydrotreatment reactors and one single fractionnation unit - Google Patents

Abstract

A process for the conversion by hydrotreatment of a hydrocarbon charge is carried out in conversion reactions (10, 110, 104, 114) and a single fractionation unit (12) arranged between them, in which both effluents of the two reactors are fractionated. The effluents of both reactors (10, 14) are recovered within two separate zones (24, 26) of the fractionator. The fractions of the effluents vapourised in (12) are re-condensed and withdrawn from a common zone (34) of the unit. Two separate withdrawals (18, 28) are effected on the distillation residues from the zones (24, 26) of the fractionation unit in which the effluents from (10, 14) are treated. The effluent from the first reactor (10) is collected in a zone (24) whilst the withdrawal (18) of distillation residues from this zone are directed to the inlet of the second reactor (14). Also claimed is the installation for effecting this process.

Description

The present invention relates to a method and a improved charge conversion device of hydrocarbons, by hydrotreating in the presence of a catalyst, using two reactors and one fractionation unit.

Generally speaking, the methods of conversion by hydrotreating aim to convert charges of high boiling point hydrocarbons and relatively cheap in lighter loads, much better recoverable.

For this purpose, it is common to put two in series conversion units or reactors: we know that high boiling charges contain some number of pollutants, especially for catalysts. In consequence, the first reactor contains a catalyst preferably selected for its resistance qualities, which, while carrying out a first conversion step, eliminates some of these pollutants, such as sulfur and nitrogen. The second reactor, on the other hand, contains a catalyst more sensitive to pollutants, but also much more active and therefore more "converting".

The effluents from the second reactor are then directed to a final split, the most of which heavy is partially recycled, in order to improve its conversion. This method nevertheless has a drawback: indeed, products already converted within the first unit is not an attractive expense for the second reactor.

In order to remedy this, one solution consists in providing a intermediate fractionation between the two units of conversion.

In this regard, the American patent will be cited US-A-4,713,167, according to which a heavy hydrocarbon charge is first sent to a first reactor hydrotreatment, where it is purified of its impurities.

The effluents from the first reactor are directed to an intermediate fractionation unit, where the lighter components formed by cracking in this first reactor are separated, while the heavy part not converted from the charge is led to a second reactor hydrocracking known as "more converting".

The effluents from this second stage can then either be fractionated by distillation in a second unit of fractionation, or much more economically (since we only use one area of fractionation instead of two), be recycled to the unit fractionation located between the two reactors.

We know that, in the latter case, it is appropriate perform a purge on the recycle line, so as not to not accumulate, in the latter, hydrocarbons heavy condensed aromatics most refractory to conversion, so as to preserve good performance at within the second reactor.

The latter solution, using only one area fractionation, nevertheless has drawbacks. In indeed, the purge performed on the recycle line contains necessarily a significant part of effluents from the first reactor, which affects its quality, whereas it is used, inter alia, to constitute oils of based. In addition, if we want to compensate at least partially this phenomenon it becomes necessary significantly increase the severity of conditions operating in the first reactor, with for pressure increases, which requires more robust reactors and therefore much more expensive.

It is also known, from US Pat. No. 3,437,584, to use a charge conversion process relatively heavy hydrocarbon such as a residue of tar type vacuum distillation comprising the introduction of this charge in a first zone of bottom of a distillation and fractionation column fitted with a vertical partition from the bottom, then the withdrawal of the charge distillation residue from this zone and its dispatch to a hydroconversion reactor. The liquid effluents from it, after separation, are introduced into a second bottom area separate from this distillation column. A distillation residue is withdrawn separately from this second bottom zone. It is not not planned to treat in a conversion reactor the heavy hydrocarbon charge before its introduction into the distillation column, and the problem of mixing distillation residues from two reactors conversion to series is therefore not addressed.

The present invention aims to provide a method of conversion to overcome the disadvantages cited above.

• les effluents des deux réacteurs sont recueillis au sein d'au moins deux zones distinctes de ladite unité de fractionnement ;
• les fractions des effluents des deux réacteurs vaporisées dans l'unité de fractionnement sont recondensées et soutirées au sein d'au moins une zone commune de cette unité ;
• des soutirages distincts sont effectués sur les résidus de distillation issus des deux zones de l'unité de fractionnement dans lesquelles les effluents des réacteurs sont traités ;
• l'effluent du premier réacteur est recueilli au sein d'une première zone de l'unité de fractionnement, tandis que le soutirage des résidus de distillation issus de ladite zone est envoyé à l'entrée du deuxième réacteur.

To this end, the subject of the present invention is a process for the conversion by hydrotreating of a hydrocarbon feedstock, using at least two conversion reactors and a single fractionation unit, disposed between them, in which the all the effluents from the two reactors, said process being characterized in that:

• the effluents from the two reactors are collected in at least two distinct zones of said fractionation unit;
• the fractions of the effluents from the two reactors vaporized in the fractionation unit are recondensed and drawn off within at least one common zone of this unit;
• separate withdrawals are carried out on the distillation residues from the two zones of the fractionation unit in which the reactor effluents are treated;
• the effluent from the first reactor is collected within a first zone of the fractionation unit, while the withdrawal of the distillation residues from said zone is sent to the inlet of the second reactor.

The process according to the invention makes it possible to avoid the mixture between the distillation residues of the effluents of the first reactor and the distillation residues of second reactor effluents, which come from a much more conversion and therefore contain the most refractory compounds.

In addition, vaporized fractions from two areas of a common fractionation unit, can then either be directed to treatments such as isomerization or the reforming of the essences, either still constituting jet fuel or diesel cuts.

Usually, the distillation residues from the fractionation unit, after having been purged, can be recycled to the second reactor and, according to a characteristic of the invention, the purge can advantageously be constituted mainly by the withdrawal of residues from the distillation of effluents of the second reactor.

The fraction recycled to the second reactor and the purge obtained are thus of improved quality, insofar as they consist mainly of residues of distillation which have been treated in two successive passes, without using fractionation units multiple.

There is also an increase in conversion, since the distillation residues of effluents from from the first reactor are largely directed to the second reactor and undergo conversion there additional.

In addition, in the case where we want to give the fraction recycled to the second reactor of the given properties, it is thanks to the invention, it is possible to work on different operating conditions in the two reactors and, in particular, at less pressure conditions severe at the level of the first reactor than those imposed by a conventional method using a single fractionation.

This "desperation", which results in particular in a pressure drop, significantly lowers the cost of treatment in the first reactor.

According to a characteristic of the invention, the purging of effluent distillation residues from the second reactor can be performed directly on a tray of distillation of the fractionation unit located above the effluent introduction zone of the first reactor.

According to another characteristic of the invention, the distillation residues from said zones can be separated from each other a vertical partitioning arranged inside the fractionation unit.

The invention also aims to propose a device for the implementation of the method described above.

• l'unité de fractionnement présente des moyens de séparation délimitant deux zones distinctes, de part et d'autre desquels débouchent respectivement les conduites d'amenée des effluents des deux réacteurs,
• l'unité de fractionnement présente deux soutirages différents, par lesquels sont extraits respectivement les résidus de distillation des effluents des deux réacteurs, et
• la conduite d'amenée de l'effluent du premier réacteur débouche dans la première zone de l'unité de fractionnement, et de cette zone sort le soutirage du résidu de distillation qui est envoyé au deuxième réacteur.

Another object of the invention therefore consists of an assembly for hydrotreating conversion of a hydrocarbon feedstock, including two reactors arranged in series, a fractionation unit disposed between these two reactors, as well as supply lines for the effluents from the reactors at the fractionation unit,
said assembly being characterized in that:

• the fractionation unit has separation means delimiting two distinct zones, on either side of which lead respectively the effluent supply pipes of the two reactors,
• the fractionation unit has two different withdrawals, by which the distillation residues of the effluents from the two reactors are extracted respectively, and
• the effluent supply line from the first reactor opens into the first zone of the fractionation unit, and from this zone withdraws the distillation residue which is sent to the second reactor.

• la figure 1 est une vue schématique d'un ensemble de conversion conforme à l'invention;
• les figures 2, 3 et 4 sont des vues schématiques représentant différents moyens de séparation, dans l'unité de fractionnement, des effluents des réacteurs ;
• la figure 5 est une vue schématique d'un autre ensemble de conversion conforme à l'invention.

Other characteristics and advantages of the invention will appear in the detailed description which follows of various embodiments. In this description, reference will be made to the appended drawings, in which:

• Figure 1 is a schematic view of a conversion assembly according to the invention;
• Figures 2, 3 and 4 are schematic views showing different means of separation, in the fractionation unit, of the reactor effluents;
• Figure 5 is a schematic view of another conversion assembly according to the invention.

As shown in Figure 1, the conversion assembly by hydrotreating a hydrocarbon charge, allowing the implementation of the process according to the invention, includes a first reactor 10, a fractionation unit 12 and a second reactor 14.

The load is brought first by a line 2 to the within reactor 10, where it undergoes a first conversion. The effluent which results therefrom is then discharged towards the unit of fractionation 12, via line 16. The corresponding distillation residue is extracted from the unit 12 by racking in 18, then is led by line 8 to the second reactor 14. The effluent from the latter is recycled through line 20 to the fractionation unit 12.

In accordance with the invention, separation means 22 which will be described in more detail below, delimit two separate zones 24, 26 of the fractionation unit 12. The supply lines 16,20 of this unit lead on either side of the separation means 22, so as to isolate distillation residues from effluents from of each reactor 10.14. In particular, the residue of distillation of the effluent from the second reactor is extracted at racking level 28, the location of which is different from that of racking 18.

This residue is then partly recycled to the second reactor 14 via line 30 and line 8, and partly evacuated from the conversion assembly via line 32, in order to constitute a purge of improved quality.

On the other hand, the vaporized fractions of the effluents from each reactor 10,14, are recondensed at level of a common area 34 and extracted from the unit of fractionation 12 by various common withdrawals 36

Figures 2, 3 and 4 show more precisely various types of separation means, in the unit of fractionation 12, admission zones 24 and 26 of effluents from the two reactors.

Thus, as shown in Figures 2 and 3, the means of separation can be constituted by a partitioning vertical, respectively 22 or 38, which extends from the bottom 40 of the fractionation unit 12.

The partition 22 can be arranged in a plane transverse vertical in unit 10 of fractionation 12 and, in particular, along a plane passing through the axis of this one (see figure 2). In this case, the pipes inlet 16, 20, effluents from each reactor lead respectively into separate zones 24, 26, located on either side of this partitioning 22. Similarly, withdrawals 18, 28 from each of the distillation residues, are arranged, at the bottom 40 of the unit 12, on either side partitioning 22.

The partition 38 can alternatively form a chimney concentric with the vertical wall 42 of the fractionation (see Figure 3). In this case, the pipes 16.20 of the effluents end up respectively in separate areas 44,46, located inside and outside outside the chimney 38. Similarly, the racking 48, 50 of each of the residues are disposed at the bottom 40 of the reactor 12, inside and outside respectively from the chimney 38.

It should be noted that the vertical partitions 22, 38, extend only over a small part of the height of the fractionation unit 12, so as to leave an area 34 of common vaporization for each of the effluents, which additionally includes common racking 36 of fractions vaporized recondensed.

According to another embodiment illustrated by the Figure 4, the separation means can be constituted by a horizontal plate 52, on either side of which lead to different heights, in the unit of fractionation 12, the effluents from each reactor.

The plate 52 is dimensioned so as to cover the entire cross section of the unit, in order to collect the distillation residue 54 from the effluent coming from the upper pipe 20. For its part, the residue 56 of the effluent from the lower pipe 16 is collected, as usual, at the bottom 40 of unit 12. In addition, the distillation residues 54, 56, are extracted at different racking levels, 58 and 60 respectively.

The plate 52 is provided with a chimney 64, surmounted by a cap 66, allowing the passage of fractions sprayed with effluent from the lower zone, towards the top of the unit 12. The cap 66 has a shape substantially conical, which directs the effluents liquids from upper line 20 on the separation plate 52, for perfect segregation residues 54, 56.

There is thus, within the fractionation unit 12, a zone 68 for common vaporization of the effluents from of each reactor 10, 14, as well as lateral withdrawals common 70 recondensed vaporized fractions.

Figure 5 shows another conversion set according to the invention. This set is similar to that shown in Figure 1, except that the unit of fractionation includes two distillation columns 72, 74.

The load is brought first by line 112 to reactor 110, where it undergoes a first conversion. The resulting effluent is then directed to the first fractionation column 72 through line 76. The residue corresponding distillation is extracted at the racking 78, then leads to the second column of fractionation 74 through line 80.

The distillation residue obtained in this second column is extracted at rack 82, then evacuated via line 112 to the second reactor 114. The effluent from the latter is recycled through line 84 to the first fractionation column 72.

The first column 72 is provided with a tray of separation 52 similar to that shown in FIG. 4, of so that the respective supply lines 76, 84 (i.e. the effluents coming respectively from the first and second reactor) open on both sides of this tray, in order to isolate from each other the residues distillation correspondents.

It should be noted that the effluents from these pipes 76, 84 vaporize within a common area 86 from column 72, then are recondensed and finally extracted at level of lateral racking 88 common.

The distillation residue from the second effluent reactor 114 is extracted by racking 90, then directed to the second column 74 via line 92. This column 74 is also provided with a horizontal plate 152 of separation, on either side from which the lines 80.92, respectively bringing the residue of distillation, in the first column 72, of the effluent from the first reactor 110, and the residue from distillation, in the first column, of the effluent from the second reactor, in order to isolate these residues the each other.

Analogously to what happens in the first column, the residues from these lines 80.92 are spray within a common area 94 of column 74, and are recondensed, then extracted at the racking level side 96 common.

The residue from the second column 74, from the distillation effluent from the second reactor 114 is then extract at rack 98, placed immediately above the separation plate 152.

This residue is then partly recycled to the second reactor via line 100, and partly directed outside the conversion assembly via line 102, in order to constitute a purge of improved quality.

The device described above is applicable to a fractionation unit including any number of columns, atmospheric or vacuum, keeping in each column the segregation between the effluents from of each reactor.

• des moyens de séparation délimitant deux zones distinctes, dans lesquelles débouchent respectivement les effluents des deux réacteur,
• deux soutirages différents, pour extraire respectivement les fractions liquides résiduelles provenant de la distillation des effluents des deux unités réactionnelles,
• et une zone de vaporisation commune des effluents issus de chaque unité réactionnelle.

For this purpose, each column presents:

• separation means delimiting two distinct zones, into which the effluents from the two reactors emerge respectively,
• two different withdrawals, for respectively extracting the residual liquid fractions originating from the distillation of the effluents from the two reaction units,
• and a common vaporization zone for the effluents from each reaction unit.

The following examples, which have no character are intended to illustrate the implementation of the invention and the advantages thereof.

Example 1

• point initial de distillation: 325°C,
• point 95 % de distillation: 640°C,
• teneur en soufre: 2,9 % en poids,
• teneur en azote: 1600 ppm,
• teneurs en nickel et en vanadium : inférieures à 2 ppm,
• teneur en asphaltènes : inférieure à 200 ppm.

A distillate cut has the following properties:

• initial point of distillation: 325 ° C,
• 95% distillation point: 640 ° C,
• sulfur content: 2.9% by weight,
• nitrogen content: 1600 ppm,
• nickel and vanadium contents: less than 2 ppm,
• asphaltenes content: less than 200 ppm.

• température: 395°C,
• pression: 190.10⁵ Pa (190 bars) à l'entrée,
• vitesse volumique horaire : 0,5 h^-1,
• catalyseur : constitué par une alumine supportant du nickel et du molybdène, du type commercialisé par Procatalyse sous la référence HR 360.

This distillate is sent to an advanced hydrorefining reactor, the operating conditions of which are as follows:

• temperature: 395 ° C,
• pressure: 190.10 ⁵ Pa (190 bars) at the inlet,
• hourly volume speed: 0.5 h ^-1 ,
• catalyst: consisting of an alumina supporting nickel and molybdenum, of the type marketed by Procatalyse under the reference HR 360.

The effluent from the first reactor is then directed to a fractionation unit, where it is separated into a fraction of gas, a fraction of gasoline, a fraction of diesel, and a residual fraction distilling above the range of diesel distillation and representing approximately 40% by weight total effluent.

• température: 350°C,
• pression: 180.10⁵ Pa (180 bars) à l'entrée,
• vitesse volumique horaire: 1 h^-1,
• catalyseur comprenant une fonction acide optimisée combinée à un support zéolithique du type Y, et une fonction hydrogénante, du type commercialisé par Procatalyse sous la référence HYC 642.

This last fraction is sent to a second hydrocracking reactor, the operating conditions of which are as follows:

• temperature: 350 ° C,
• pressure: 180.10 ⁵ Pa (180 bars) at the inlet,
• hourly volume speed: 1 h ^-1 ,
• catalyst comprising an optimized acid function combined with a zeolitic support of the Y type, and a hydrogenating function of the type marketed by Procatalyse under the reference HYC 642.

The effluent from the second reactor is then returned to the fractionation unit. A purge is also drawn off at from the residual fraction from the splitting.

At the same time, the same starting distillate as in the above experience, is converted by a conforming process to the invention.

It is therefore directed to a first reactor hydrotreatment whose operating conditions are same as above. The resulting effluent is directed to a fractionation unit with means for separation according to the invention.

The residual fraction from this fractionation is sent to a hydrocracking reactor, the operating conditions are the same as in the first experience. The effluent from this second reactor is directed towards fractionation, where its residual fraction is isolated so as to constitute the purge.

The table below brings together the properties of the diesel and the purge obtained in accordance with the invention on the one hand, and without segregation of the fractionation residues on the other hand. Diesel Without segregation According to the invention Initial distillation point (PI) 250 ° C 250 ° C Final distillation point (PF) 375 ° C 375 ° C Sulfur content 15 ppm 15 ppm Cetane number 52 56 Purge Without segregation According to the invention PI 375 ° C 375 ° C Point 95% 600 ° C 600 ° C Viscosity at 100 ° C (in mm ² / s or cst): - before dewaxing 5.2 5 - after dewaxing 5.4 5.2 Viscosity Index (VI) : - before dewaxing 140 145 - after dewaxing 120 125

As shown in the table above, the process conforms the invention allows, with equal severity, to obtain higher quality products (higher cetane number for diesel, lower viscosity and higher VI index for purging).

Example 2

• point initial de distillation : 325°C,
• point 95 % de distillation : 640°C,
• teneur en soufre : 2,9 % en poids,
• teneur en azote : 1600 ppm,
• teneurs en nickel et en vanadium : inférieures à 2 ppm,
• teneur en asphaltènes : inférieure à 200 ppm.

A distillate cut has the following properties:

• initial point of distillation: 325 ° C,
• 95% distillation point: 640 ° C,
• sulfur content: 2.9% by weight,
• nitrogen content: 1600 ppm,
• nickel and vanadium contents: less than 2 ppm,
• asphaltenes content: less than 200 ppm.

• température : 395°C,
• pression: 190.10⁵ Pa (190 bars) à l'entrée,
• vitesse volumique horaire : 0.5 h^-1,
• catalyseur : constitué par une alumine supportant du nickel et du molybdène, tel que commercialisé par Procatalyse sous la référence HR 360.

This distillate is treated towards a first hydrotreatment reactor under the following operating conditions:

• temperature: 395 ° C,
• pressure: 190.10 ⁵ Pa (190 bars) at the inlet,
• hourly volume speed: 0.5 h ^-1 ,
• catalyst: consisting of an alumina supporting nickel and molybdenum, as marketed by Procatalyse under the reference HR 360.

The effluent from the first reactor is then directed to a fractionation unit, where it is separated into a fraction of gas, a fraction of gasoline, a fraction of diesel, and a residual fraction distilling above the range of diesel distillation and representing approximately 40% by weight total effluent.

• température : 350°C,
• pression : 180.10⁵ Pa (180 bars) à l'entrée,
• vitesse volumique horaire : 1 h^-1,
• catalyseur comprenant une fonction acide optimisée combinée à un support zéolithique du type Y, et une fonction hydrogénante, du type commercialisé par Procatalyse sous la référence HYC 642.

This last fraction is sent to a hydrocracker, the operating conditions of which are as follows:

• temperature: 350 ° C,
• pressure: 180.10 ⁵ Pa (180 bars) at the inlet,
• hourly volume speed: 1 h ^-1 ,
• catalyst comprising an optimized acid function combined with a zeolitic support of the Y type, and a hydrogenating function of the type marketed by Procatalyse under the reference HYC 642.

The effluent from the second reactor is then returned to the splitting. A purge is also drawn off from the residual fraction from the fractionation.

This purge has the following properties: Purge Without segregation According to the invention PI 375 ° C 375 ° C Point 95% 600 ° C 600 ° C Viscosity at 100 ° C (in mm ² / s or cst) - before dewaxing 5.2 5 - after dewaxing 5.4 5.2 Index VI - before dewaxing 140 145 - after dewaxing 120 125

At the same time, the same starting distillate as in the usual process above is subject to the process according to the invention.

We adjust the operating conditions in the first reactor so that the purge obtained has the same properties as in the above experiment

• température : 395°C,
• pression : 140.10⁵ Pa (140 bars) à l'entrée,
• vitesse volumique horaire : 0.5 h^-1.

The operating conditions are then as follows:

• temperature: 395 ° C,
• pressure: 140.10 ⁵ Pa (140 bar) at the inlet,
• hourly volume speed: 0.5 h ^-1 .

This second example shows that, with equivalent product qualities, the severity of the process according to the invention is much lower than that of the prior art. Thus, the pressure prevailing in the first reactor is 50.10 ⁵ Pa (50 bar) lower, which results in a very significant reduction in cost.

Claims (15)

1. Process for the conversion by hydrotreatment of a hydrocarbon-containing feedstock, using at least two conversion reactors (10, 110, 14, 114) and a single fractionating unit (12) disposed in-between, in which all the effluents from the two reactors are fractionated, said process being characterised in that:

   the effluents from the two reactors (10, 110, 14, 114) are collected within at least two distinct zones (24, 26) of said fractionating unit (12);

   the effluent fractions from the two reactors (10, 110, 14, 114) vaporised in the fractionating unit (12) are recondensed and tapped within at least one common zone (34) of this unit;

   distinct tappings (18, 28) are carried out on the distillation residues issuing from the two zones (24, 26) of the fractionating unit (12) in which the effluents from the reactors (10, 110, 14, 114) are treated;

   the effluent from the first reactor (10, 110) is collected within a first zone (24) of the fractionating unit, whereas the tapping (18) of the distillation residues issuing from said zone (24) is conveyed to the inlet of the second reactor (14, 114).
2. Process according to claim 1, characterised in that purging (32) of improved quality, containing the heavy hydrocarbons which are most refractory on conversion, is carried out predominantly on the tapping (28) of the distillation residue issuing from the effluent from the second reactor (14, 114), in the second zone (26) of the fractionating unit (12).
3. Process according to claim 2, characterised in that a proportion of the distillation residue issuing from the tapping (28), from the second zone (26) of the fractionating unit, is recycled toward the second reactor (14, 114).
4. Process according to any of claims 1 to 3, characterised in that different operating conditions are employed in the two reactors (10, 110, 14, 114), in particular less stringent pressure conditions in the first reactor (10, 110).
5. Process according to any of claims 1 to 4, characterised in that the purging of the distillation residues of the effluents issuing from the second reactor (14, 114) is carried out directly on a distillation plate (52) situated above the zone of introduction of the effluents from the first reactor (10, 110).
6. Process according to any of claims 1 to 4, characterised in that the distillation residues issuing from said zones (24, 26) of the fractionating unit (12) are isolated from one another by means of a vertical partition (22, 38) disposed inside the fractionating unit.
7. Assembly for the conversion by hydrotreatment of a hydrocarbon-containing feedstock, including two reactors (10, 110, 14, 114) disposed in series, a fractionating unit (12) disposed between these two reactors, as well as effluent feed pipes from the reactors to the fractionating unit,
   said assembly being characterised in that:

   the fractionating unit (12) has separating means (22, 38) delimiting two distinct zones (24, 26), on either side of which there open the respective effluent feed pipes (16, 20) from the two reactors (10, 110, 14, 114),

   the fractionating unit (12) has two different tappings (18, 28) through which the respective distillation residues of the effluents from the two reactors (10, 110, 14, 114) are extracted, and

   the effluent feed pipe from the first reactor (10, 110) opens into the first zone (24) of the fractionating unit, and the tapping (18) of the distillation residue conveyed to the second reactor (14, 114) issues from this zone.
8. Conversion assembly according to claim 7, characterised in that the separating means consist of a vertical partition (22, 38) extending from the bottom (60) of the fractionating unit (12).
9. Conversion assembly according to claim 8, characterised in that the partition forms a shaft (38) concentric with the vertical wall (42) of the fractionating unit (12).
10. Conversion assembly according to claim 8, characterised in that the partition is a wall (22) disposed in a transverse plane of the fractionating unit (12).
11. Conversion assembly according to claim 7, characterised in that the separating means (52) are horizontal and in that the two effluent feed pipes (16, 20) from the two reactors (10, 110, 14, 114) open at different heights of the fractionating unit (12).
12. Conversion assembly according to claim 11, characterised in that the horizontal separating means consist of a plate (52) provided with at least one shaft (54).
13. Conversion assembly according to any of claims 7 to 12, characterised in that the fractionating unit (12) includes a common vaporisation zone (34) for the effluents issuing from each reactor (10, 110, 14, 114).
14. Conversion assembly according to any of claims 7 to 13, in which the fractionating unit comprises at least two columns (72, 74), at atmospheric pressure or under vacuum, disposed in series,
    characterised in that each column comprises:

    separating means (52, 152) delimiting two distinct zones, on either side of which the effluents from the two reactors (10, 110, 14, 114) emerge,

    two different tapping means (80, 90; 82, 98) through which the respective residual liquid fractions of the effluents from the two reactors are extracted,

    and a common vaporisation zone (86, 94) for the effluents issuing from each reactor.
15. Conversion assembly according to any of claims 7 to 14, characterised in that the first reactor is a hydrotreatment reactor and in that the second reactor is a hydrocracking reactor.

Images