EP3026097A1 - Method for producing fuels such as heavy fuel oil from a heavy hydrocarbon feedstock using a separation between the hydrotreating step and the hydrocracking step - Google Patents

Abstract

The present invention describes a method for producing heavy fuel type fuel, which fuel can optionally become a marine fuel, from a heavy hydrocarbon feedstock having a sulfur content of at least 0.5% by weight, a temperature initial boiling point of at least 350 ° C and a final boiling temperature of at least 450 ° C, using a fixed bed hydrotreating step, an intermediate separation and a hydrocracking step having at least one hybrid type reactor.

Description

FIELD OF THE INVENTION

The present invention relates to the refining and conversion of heavy hydrocarbon fractions containing, inter alia, sulfur impurities. It relates more particularly to a process for treating heavy petroleum feedstocks for the production of fuel oils and oil bases, in particular bunker oil and bunker oil bases, with low sulfur content and low sediment content.

EXAMINATION OF THE PRIOR ART

The object of the present invention is to produce fuel oils and oil bases, in particular bunker oil and bunker oil bases, which comply with the recommendations of the MARPOL convention in terms of equivalent sulfur content, and preferably also respecting the recommendations on sediment content after aging, as described for marine fuels in ISO8217.

Fuel oils used in maritime transport generally include atmospheric distillates, vacuum distillates, atmospheric residues and vacuum residues from direct distillation or from refining processes, including hydrotreatment and conversion processes, which may be be used alone or mixed. Another object of the present invention is to jointly produce, by the same method, atmospheric distillates (naphtha, kerosene, diesel), vacuum distillates and / or light gases (C1 to C4). The bases of the naphtha and diesel type can be upgraded to refineries for the production of automotive and aviation fuels, such as, for example, super-fuels, Jet fuels and gas oils.

• US7815870 qui décrit un procédé d'hydrocraquage avec au moins un lit bouillonnant opérant avec un catalyseur supporté et un cata dispersé (mode hybride). Dans ce document il peut y avoir en complément un ou des réacteurs de type lit fixe ou "slurry" en amont ou en aval, mais dans tous les cas, le lit bouillonnant opère en mode hybride. Mais le document cité ne décrit pas les conditions d'un enchainement avec une étape d'hydrotraitement préalable permettant les performances en hydrodésulfuration et en conversion telles que présentées dans la présente demande. Le document cité ne décrit pas non plus le post traitement permettant la réduction de la teneur en sédiments de manière à satisfaire les exigences de qualité des fiouls de soute.
• US5358629 / US5622616 / US5868923 qui décrivent l'injection de cata dispersé dans un lit bouillonnant. Les procédés décrits dans ces textes ne décrivent pas d'hydrotraitement en amont.

Relevant prior art documents include:

• US7815870 which describes a hydrocracking process with at least one bubbling bed operating with a supported catalyst and a dispersed cat (hybrid mode). In this document there may be in addition to one or more reactors of fixed bed type or "slurry" upstream or downstream, but in all cases, the bubbling bed operates in hybrid mode. But the cited document does not describe the conditions of a sequence with a prior hydrotreatment step for hydrodesulfurization performance and conversion as presented in this application. The document cited does not describe either the post-processing allowing the reduction of sediment content to meet the quality requirements of bunker fuels.
• US5358629 / US5622616 / US5868923 which describe the injection of cata dispersed in a bubbling bed. The processes described in these texts do not describe upstream hydrotreatment.

None of these documents therefore describes the production of a fuel oil or ultra-low sulfur fuel oil bases meeting the new recommendations of the International Maritime Organization, and low sediment content as required by the new version of the standard. ISO 8217: 2012.

The present invention makes it possible to improve the conversion processes described in the state of the art for the production of fuel oils and bases of low-sulfur fuel oils.

• une étape d'hydrotraitement dont l'un au moins des réacteurs fonctionne en lit fixe,
• une étape de séparation des effluents de l'étape d'hydrotraitement permettant de dégager une coupe lourde,
• une étape d'hydrocraquage de ladite coupe lourde faisant appel à des réacteurs dont l'un au moins est de type hybride.
• une étape de séparation de l'effluent de l'étape d'hydrocraquage permettant de dégager une coupe lourde,
• une étape facultative de traitement des sédiments de ladite coupe lourde.
• une étape facultative de séparation de l'effluent de l'étape de traitement des sédiments

It is based on the following sequence of steps:

• a hydrotreatment step of which at least one of the reactors operates in a fixed bed,
• a step of separation of the effluents of the hydrotreatment step making it possible to release a heavy cut,
• a step of hydrocracking said heavy cut using reactors of which at least one is of hybrid type.
• a step of separating the effluent from the hydrocracking step making it possible to release a heavy cut,
• an optional sediment treatment step of said heavy cut.
• an optional effluent separation step from the sediment treatment stage

SUMMARY DESCRIPTION OF THE FIGURES

• The figure 1 represents a schematic view of the process according to the invention, showing a hydrotreatment zone, a zone for separating the effluent from the hydrotreatment zone, a hydrocracking zone and a zone for separating the effluent from the hydrotreatment zone. hydrocracking zone and a sediment treatment / separation zone contained in the heavy cut from the separation zone of the hydrocracking effluent.
• The figure 2 is a schematic view of the process according to the invention in a variant in which the separation zone of the effluent of the hydrotreatment zone is simplified.
  For the sake of clarity, the limits of each step have been represented symbolically on the figures 1 and 2 : "A" means the hydrotreatment zone, "B" means the separation zone intermediate, "C" designates the hydrocracking zone and "D" designates the zone of separation of the effluent from the hydrocracking zone and "E" denotes the sediment treatment zone.

SUMMARY DESCRIPTION OF THE INVENTION

1. a) une étape d'hydrotraitement en lit fixe, dans laquelle la charge hydrocarbonée et de l'hydrogène sont mis en contact sur un catalyseur d'hydrotraitement,
2. b) une étape de séparation de l'effluent obtenu à l'issue de l'étape (a) d'hydrotraitement en au moins une fraction légère et au moins une fraction lourde,
3. c) une étape d'hydrocraquage d'au moins une partie de la fraction lourde de l'effluent issu de l'étape (b), prise seule ou en mélange avec d'autres coupes résiduelles ou fluxantes, dans au moins un réacteur fonctionnant en mode hybride, c'est-à-dire fonctionnant en lit bouillonnant avec un catalyseur supporté associé à un catalyseur "dispersé" constitué de particules de catalyseur très fines constituant une suspension avec la phase liquide hydrocarbonée à traiter,
4. d) une étape de séparation de l'effluent issu de l'étape (c) pour obtenir au moins une fraction légère et au moins une fraction lourde, ladite fraction lourde constituant la fraction hydrocarbonée liquide annoncée dans le préambule,
5. e) une étape de traitement de la fraction lourde issue de l'étape d) permettant de réduire la teneur en sédiments de ladite fraction lourde,
6. f) une étape de séparation finale de l'effluent issu de l'étape de traitement e) pour obtenir ladite fraction hydrocarbonée liquide à teneur réduite en sédiments.

The present invention can be defined as a process for treating a heavy hydrocarbon feed having a sulfur content of at least 0.5% by weight, an initial boiling temperature of at least 350 ° C, and a temperature final boiling point of at least 450 ° C, for obtaining at least one liquid hydrocarbon fraction having a sulfur content of less than or equal to 0.5% by weight, the process comprising the following successive steps:

1. a) a fixed bed hydrotreatment step, wherein the hydrocarbon feedstock and hydrogen are contacted on a hydrotreatment catalyst,
2. b) a step of separating the effluent obtained at the end of the hydrotreatment step (a) into at least a light fraction and at least one heavy fraction,
3. c) a step of hydrocracking at least a portion of the heavy fraction of the effluent from step (b), taken alone or mixed with other residual or fluxing cuts, in at least one operating reactor in hybrid mode, that is to say operating in a bubbling bed with a supported catalyst associated with a "dispersed" catalyst consisting of very fine catalyst particles constituting a suspension with the hydrocarbon liquid phase to be treated,
4. d) a step of separating the effluent from step (c) to obtain at least one light fraction and at least one heavy fraction, said heavy fraction constituting the liquid hydrocarbon fraction announced in the preamble,
5. e) a step of treating the heavy fraction resulting from step d) making it possible to reduce the sediment content of said heavy fraction,
6. f) a final separation step of the effluent from the treatment step e) to obtain said sediment-reduced liquid hydrocarbon fraction.

An ebullating bed can be defined as a fluidized solid-liquid gas bed in which the catalyst particles have a size of between 0.5 and 1.5 mm, preferably between 0.8 mm and 1.2 mm, and still more preferred between 0.9 mm and 1.1 mm.

A hybrid type of bed corresponds to a bubbling bed in which an additional injection of a dispersed catalyst was made.

A dispersed catalyst is a catalyst in the form of very fine particles, that is to say generally a size of between 1 nanometer (ie 10 ^-9 m) and 150 micrometers, preferably between 0.1 and 100 micrometers, and even more preferred, between 10 and 80 microns.

A hybrid bed thus comprises two populations of catalyst, a population of bubbling bed catalyst to which is added a population of dispersed type catalyst.

The HCAT® technology marketed by the company HTI is an example of implementation of dispersed catalyst injected into a bubbling bed reactor.

The process for treating a heavy hydrocarbon feedstock according to the present invention can be broken down into several variants.

In a first variant, the hydrocracking step c) comprises a first bubbling bed reactor followed by a second "hybrid" type bed reactor (that is to say of the bubbling bed type with catalyst injection type "scattered").

In a second variant, the hydrocracking step c) comprises a first hybrid bed type reactor followed by a second hybrid type reactor.

In a third variant, the hydrocracking step c) comprises a single hybrid bed type reactor.

• une température comprise entre 300°C et 500°C, de préférence entre 350°C et 420°C, une pression absolue comprise entre 2 MPa et 35 MPa, de préférence entre 11 MPa et 20 MPa,
• une vitesse spatiale de la charge hydrocarbonée, couramment appelée VVH, qui se définit comme étant le débit volumétrique de la charge pris aux conditions du procédé divisé par le volume total du réacteur, comprise dans une gamme allant de 0,1 h-1 à 5 h-1, préférentiellement de 0,1 h-1 à 2 h-1, et plus préférentiellement de 0,1 h-1 à 0,45 h-1,
• une quantité d'hydrogène mélangée à la charge comprise entre 100 et 5000 normaux mètres cube (Nm3) par mètre cube (m3) de charge liquide, préférentiellement entre 200 Nm3/m3 et 2000 Nm3/m3, et plus préférentiellement entre 300 Nm3/m3 et 1500 Nm3/m3.

The process for treating a heavy hydrocarbon feedstock according to the present invention comprises a step a) of hydrotreatment in a fixed bed operated under the following conditions:

• a temperature of between 300 ° C. and 500 ° C., preferably between 350 ° C. and 420 ° C., an absolute pressure of between 2 MPa and 35 MPa, preferably between 11 MPa and 20 MPa,
• a space velocity of the hydrocarbon feedstock, commonly referred to as VVH, which is defined as the volumetric flow rate of the feedstock taken at the process conditions divided by the total reactor volume, in a range from 0.1 hr -1 to 5 h-1, preferentially from 0.1 h -1 to 2 h -1, and more preferably from 0.1 h -1 to 0.45 h -1,
• a quantity of hydrogen mixed with the charge of between 100 and 5000 normal cubic meters (Nm3) per cubic meter (m3) of liquid charge, preferably between 200 Nm3 / m3 and 2000 Nm3 / m3, and more preferably between 300 Nm3 / m3 and 1500 Nm3 / m3.

• une pression partielle d'hydrogène variant de 2 à 35 MPa, et préférentiellement de 10 à 25 MPa,
• une température comprise entre 330°C et 550°C, de préférence de 350°C à 500°C, encore plus préférentiellement entre 370°C et 480°C,
• une vitesse spatiale horaire (VVH réacteur, soit ratio entre le débit volumique de charge et le volume de réacteur) comprise entre 0,1 et 10 h-1, de préférence de 0,1 h à 5 h-1 et de manière plus préférée entre 0,1 et 2 h-1,
• une vitesse spatiale horaire "catalyseurs lit bouillonnant" pour les réacteurs lit bouillonnant ou hybride comprise entre 0,1 et 5 h-1, de préférence de 0,1 h à 3 h-1 et de manière plus préférée entre 0,1 et 1 h-1, la VVH « catalyseur lit bouillonnant étant définie comme le ratio entre le débit volumique de charge en m3/h et le volume en m3 de catalyseur lit bouillonnant au repos, c'est à dire lorsque le taux d'expansion du lit bouillonnant est nul,
• une teneur en composés métalliques dans les catalyseurs utilisés en lit hybride comprise entre 0 et 10% pds, de préférence entre 0 et 1% pds, ladite teneur étant exprimée en pourcentage poids d'éléments métalliques du groupe VIII et/ou du groupe VIB,
• un rapport hydrogène/charge compris entre 50 et 5000 Nm3/m3, préférentiellement compris entre 100 et 1500 Nm3/m3 avec une gamme encore préférée entre 500 et 1300 Nm3/m3.

The process according to the present invention also uses a hydrocracking step c) treating at least one heavy fraction resulting from the separation of the effluent from the hydrotreating step. This hydrocracking stage comprises at least one hybrid type reactor, this reactor generally operating under the following conditions:

• a hydrogen partial pressure ranging from 2 to 35 MPa, and preferably from 10 to 25 MPa,
• a temperature of between 330 ° C. and 550 ° C., preferably of 350 ° C. to 500 ° C., even more preferentially of between 370 ° C. and 480 ° C.,
• a hourly space velocity (VVH reactor, ie ratio between the charge volume flow rate and the reactor volume) of between 0.1 and 10 h -1, preferably from 0.1 h to 5 h -1, and more preferably between 0.1 and 2 h-1,
• a hourly space velocity "bubbling bed catalysts" for bubbling or hybrid bed reactors between 0.1 and 5 h -1, preferably from 0.1 h to 3 h -1 and more preferably between 0.1 and 1 h -1 h-1, the VVH "bubbling bed catalyst being defined as the ratio between the volume flow rate of charge in m3 / h and the volume in m3 of bubbling bed catalyst at rest, that is to say when the rate of expansion of the bed bubbling is nil,
• a content of metal compounds in the catalysts used in a hybrid bed of between 0 and 10% by weight, preferably between 0 and 1% by weight, said content being expressed as a percentage by weight of Group VIII and / or Group VIB metal elements,
• a hydrogen / charge ratio of between 50 and 5000 Nm3 / m3, preferably between 100 and 1500 Nm3 / m3 with a still more preferred range between 500 and 1300 Nm3 / m3.

In a variant of the process for treating a heavy hydrocarbon feedstock according to the invention, the said liquid hydrocarbon fraction resulting from the separation step d) is furthermore subjected to a treatment stage e) making it possible to treat and separate sediments and residues from catalysts, by maturation converting potential sediments into existing sediments and then physical separation allowing the elimination of all existing sediments.

In another variant of the process for treating a heavy hydrocarbon feedstock according to the present invention, said liquid hydrocarbon fraction is further subjected to a step of recovering the "dispersed" catalyst in addition to the treatment step e) for treating and separating sediments and catalyst residues.

The step d) of separation of the effluent resulting from the hydrocracking step can be carried out either in a summary manner, allowing one or two liquid fractions to be obtained, or in a more complete manner allowing then to obtain at least three liquid fractions.

The separation d) carried out more completely thus makes it possible to obtain well-separated atmospheric and / or vacuum distillate cuts (naphtha, kerosene, gas oil, vacuum gas oil, for example) from the atmospheric residue and / or under vacuum.

The manner in which this separation step is performed conditions the continuation of the optional steps e) and f).

The treatment step e) makes it possible to convert, by maturation, the potential sediments contained in the heavy fraction resulting from the upstream separation d), into existing sediments, and then to separate them from the liquid fraction. This treatment step therefore involves a physical separation of the sediments formed. In order not to introduce confusion with respect to the upstream and downstream separations f), we have not given a specific name to this separation, which therefore forms an integral part of the processing step e).

The final optional separation step f) is necessary in the case where the upstream separation d) has been carried out in a summary manner. The final separation step f) then makes it possible to separate the heavy hydrocarbon fraction with reduced sediment content which can then constitute a marine fuel in the sense of the ISO8217 standard.

DETAILED DESCRIPTION OF THE INVENTION

Throughout the description, the expression that follows the phrase "included between ... and ..." shall be understood to include the cited boundaries.

• une étape (a) d'hydrotraitement en lit fixe, puis
• une étape (b) de séparation de l'effluent hydrotraité en au moins une fraction légère et au moins une fraction lourde,
• une étape (c) d'hydrocraquage d'au moins une partie de la fraction lourde issue de l'étape (b), prise seule ou en mélange avec d'autres coupes résiduelles ou fluxantes, dans au moins un réacteur fonctionnant en mode hybride, c'est-à-dire fonctionnant en lit bouillonnant avec un catalyseur supporté associé à un catalyseur "dispersé" constitué de particules de catalyseur très fines constituant une suspension avec la phase liquide hydrocarbonée à traiter,
• une étape (d) de séparation de l'effluent de la zone d'hydrocraquage c) permettant d'obtenir au moins une fraction légère et au moins une fraction lourde,
  • e) une étape facultative de traitement des sédiments permettant de réduire la teneur en sédiments de la fraction lourde et d'obtenir ladite fraction hydrocarbonée liquide à teneur réduite en sédiments (inférieure à 0,1 % poids).
  • f) une étape facultative de séparation finale de l'effluent issu de l'étape de traitement e) pour obtenir des distillats et ladite fraction hydrocarbonée liquide à teneur réduite en sédiments.

The method according to the invention therefore comprises:

• a step (a) of hydrotreatment in fixed bed, then
• a step (b) of separating the hydrotreated effluent into at least a light fraction and at least one heavy fraction,
• a step (c) of hydrocracking at least a portion of the heavy fraction resulting from step (b), taken alone or mixed with other residual or fluxing cuts, in at least one reactor operating in hybrid mode that is to say operating in a bubbling bed with a supported catalyst associated with a "dispersed" catalyst consisting of very fine catalyst particles constituting a suspension with the hydrocarbon liquid phase to be treated,
• a step (d) for separating the effluent from the hydrocracking zone c) making it possible to obtain at least one light fraction and at least one heavy fraction,
  • e) an optional sediment treatment step for reducing the sediment content of the heavy fraction and obtaining said sediment-reduced liquid hydrocarbon fraction (less than 0.1% by weight).
  • f) an optional step of final separation of the effluent from the treatment step e) to obtain distillates and said sediment-reduced liquid hydrocarbon fraction.

The scope of the present invention is defined by the fact that one of the reactors of the hydrocracking zone is of the "hybrid" type, the other reactors of the hydrocracking zone possibly being of a bubbling type, or "hybrid" ". For simplicity in the rest of the text we will speak of hydrocracking zone mode or bed "hybrid".

The objective of step a) of fixed bed hydrotreating is both to refine, that is to say substantially reduce the content of metals, sulfur and other impurities, and to improve the hydrogen ratio on carbon (H / C) of the hydrocarbon feed while transforming said hydrocarbon feedstock at least partially into lighter cuts.

The effluent obtained at the end of the step (a) of hydrotreating in fixed bed is then subjected to a separation step b) to obtain different fractions. This separation makes it possible to remove from the effluent obtained at the end of step (a) of hydrotreatment the lighter fractions which do not require additional treatment, or a moderate treatment, and to recover a heavy fraction which is sent to step (c) hybrid bed hydrocracking which partially converts said heavy fraction to produce an effluent that can be used totally or partly as fuel oil or as fuel oil base, especially as bunker oil or as a fuel oil base.

One of the interests of the sequence of a hydrotreatment in a fixed bed, then of a hydrocracking in a "hybrid" bed lies in the fact that the charge of the hybrid bed hydrocracking reactor is already at least partially hydrotreated.

In this way, it is possible to obtain equivalent conversion of hydrocarbon effluents of better quality, in particular with lower sulfur contents.

In addition, the supported and dispersed catalyst consumption in the hybrid bed hydrocracking step is greatly reduced compared to a process without prior fixed bed hydrotreatment.

The intermediate separation step b) between the hydrotreatment step a) and the hydrocracking step c) advantageously makes it possible to minimize the fraction to be treated in said hydrocracking step c). In this way, the capacity of the hybrid bed hydrocracking reaction section may be less important. Likewise, over-cracking of the light fractions is avoided and thus a loss of yield of fuel-type fractions is avoided.

The separation step b) also makes it possible to eliminate a portion of the hydrogen introduced upstream of the hydrotreatment step a), which makes it possible to work with different hydrogen coverage levels in step a ) hydrotreatment and hydrocracking step c). The elimination, during the separation step b), of light fraction, and in particular of a large part of the hydrogen sulphide formed during step a) of hydrotreatment, makes it possible to work at a partial pressure of higher hydrogen (for the same total pressure) during the hydrocracking step, thus leading to products of better quality.

The hydrocarbon feedstock

The hydrocarbon feedstock treated in the process according to the invention can be described as a heavy load. It has an initial boiling point of at least 350 ° C and a final boiling temperature of at least 450 ° C. Preferably, its initial boiling point is at least 375 ° C., and its final boiling point is at least 460 ° C., preferably at least 500 ° C., and even more preferably at least minus 600 ° C. The hydrocarbon feedstock may be chosen from atmospheric residues (RA) obtained from an atmospheric distillation, vacuum residues (RSV) resulting from vacuum distillation, deasphalted oils, deasphalting resins, asphalts or deasphalting pitches. , residues resulting from conversion processes such as coking, aromatic extracts from lubricant base production lines, oil sands or derivatives thereof, oil shales or their derivatives, parent rock oils or their derivatives, whether alone or in admixture.

In the present invention, the charges which are treated are preferably atmospheric residues (RA) or vacuum residues (RSV), or residues of conversion processes, or any mixtures of these different types of residues.

In addition, the hydrocarbon feedstock treated in the process according to the invention is sulfurized.

Its sulfur content is at least 0.5% by weight, preferably at least 1% by weight, more preferably at least 2% by weight.

In addition, the hydrocarbon feedstock treated in the process according to the invention may contain asphaltenes. Its asphaltenes content may be at least 1% by weight, preferably at least 2% by weight.

These charges can be used as is or diluted by a co-charge. This co-charge may be a hydrocarbon fraction or a mixture of lighter hydrocarbon fractions, which may preferably be chosen from products derived from a fluid-bed catalytic cracking (FCC) process, a light cutting oil (LCO or light cycle oil "according to the English terminology), a heavy cutting oil (HCO or" heavy cycle oil "according to the English terminology), a decanted oil, an FCC residue, a diesel fraction, in particular a fraction obtained by atmospheric or vacuum distillation, such as vacuum gas oil, or may come from another refining process.

The co-charge may also consist of one or more cuts from the process of liquefying coal or biomass, aromatic extracts, or any other hydrocarbon cuts or non-petroleum fillers such as pyrolysis oil.

The heavy hydrocarbon feedstock according to the invention may represent at least 50%, preferably 70%, more preferably at least 80%, and even more preferably at least 90% by weight of the total hydrocarbon feedstock treated by the process according to the invention.

Step (a) Hydroprocessing

The heavy hydrocarbon feedstock is subjected according to the process of the present invention to a fixed bed hydrotreating step (a) in which feedstock and hydrogen are contacted on a hydrotreatment catalyst.

Hydroprocessing, commonly known as HDT, is understood to mean catalytic treatments with hydrogen supply that make it possible to refine, that is to say, to substantially reduce the content of metals, sulfur and other impurities contained in the hydrocarbon feed while increasing the ratio hydrogen on carbon charge.

Hydroprocessing is accompanied by the formation of lighter cuts than the starting load. Hydrotreatment includes, in particular, hydrodesulfurization reactions (commonly referred to as HDS), hydrodenitrogenation reactions (commonly referred to as HDN), and hydrodemetallation reactions (commonly referred to as HDM), accompanied by hydrogenation, hydrodeoxygenation, hydrogenation, and hydrogenation reactions. hydrodearomatization, hydroisomerization, hydrodealkylation, hydrocracking, hydro-deasphalting and Conradson carbon reduction.

According to a preferred variant, the hydrotreatment step (a) comprises a first hydrodemetallization (HDM) step (a1) carried out in one or more hydrodemetallation zones in fixed beds, and a second (a2) subsequent step of hydrodesulfurization (HDS) carried out in one or more hydrodesulfurization zones in fixed beds.

According to a preferred embodiment, the fixed-bed hydrotreating zone may comprise permutable reactors, for example reactive guards reactors which, in a sequence including stages of operation, stopping, unloading and replacement of the catalyst, , a longer cycle time, especially for loads with a high metal content.

During said first hydrodemetallation step (a1), the feedstock and the hydrogen are contacted on a hydrodemetallization catalyst, under hydrodemetallation conditions, and then during said second hydrodesulphurization step (a2). the effluent of the first hydrodemetallation step (a1) is contacted with a hydrodesulfurization catalyst under hydrodesulfurization conditions. This process, known as HYVAHL-F ™, is for example described in US Patent 5,417,846 .

Between the hydrodemetallation step and the hydrodesulfurization step, the person skilled in the art sometimes defines a transition zone. Whether during the hydrodemetallation stage, during the transition stage, or during the hydrodesulfurization stage, all types of reaction hydrotreatment occur. However, these appellations come in particular from the fact that the majority of the metals are removed during the hydrodemetallization step, whereas during the hydrodesulfurization step, the majority of the reactions taking place are of the hydrodesulfurization type.

The hydrotreatment step (a) according to the invention may advantageously be carried out at a temperature of between 300 ° C. and 500 ° C., preferably between 350 ° C. and 420 ° C., and under an absolute pressure of between 2 MPa and 35 MPa, preferably between 11 MPa and 20 MPa.

Most often, the space velocity of the hydrocarbon feedstock, commonly referred to as VVH, which is defined as the volumetric flow rate of the feed taken at the process conditions divided by the total volume of the reactor, can be in a range from 0, 1 h ^-1 to 5 h ^-1 , preferably from 0.1 h ^-1 to 2 h ^-1 , and more preferably from 0.1 h ^-1 to 0.45 h ^-1 .

The quantity of hydrogen mixed with the feedstock may be between 100 and 5000 normal cubic meters (Nm ³ ) per cubic meter (m ³ ) of liquid feedstock, preferably between 200 Nm ³ / m ³ and 2000 Nm ³ / m ³ , and more preferably between 300 Nm ³ / m ³ and 1500 Nm ³ / m ³ . The hydrotreating step (a) can be carried out industrially in one or more liquid downflow reactors.

The hydrotreatment catalysts used are generally granular catalysts comprising, on a support, at least one metal or metal compound having a hydrodehydrogenating function. These catalysts may advantageously be catalysts comprising at least one Group VIII metal, generally selected from the group consisting of nickel and cobalt, and / or at least one Group VIB metal, preferably molybdenum and / or tungsten.

For example, it is possible to use a catalyst comprising from 0.5% to 10% by weight of nickel, preferably from 1% to 5% by weight of nickel (expressed as nickel oxide NiO), and from 1% to 30% by weight of nickel. weight of molybdenum, preferably from 5% to 20% by weight of molybdenum (expressed as MoO ₃ molybdenum oxide) on a mineral support.

This support may for example be chosen from the group consisting of alumina, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals. In the case of a hydrotreating step including a hydrodemetallation (HDM) step and then a hydrodesulphurization step (HDS), specific catalysts adapted to each step are preferably used.

Catalysts that can be used in the HDM step are, for example, indicated in the patent documents EP 0113297 , EP 0113284 , US 5221656 , US 5827421 , US 7119045 , US 5622616 and US 5089463 . HDM catalysts are preferably used in the reactive reactors.

Catalysts that can be used in the HDS step are, for example, indicated in the patent documents EP 0113297 , EP 0113284 , US 6589908 , US 4818743 or US 6332976 .

It is also possible to use a mixed catalyst, active in HDM and HDS, for both the HDM section and the HDS section as described in the patent document. FR 2940143 . Prior to the injection of the feed, the catalysts used in the process according to the present invention are preferably subjected to an in-situ or ex-situ sulphurization treatment.

Step (b) intermediate separation

The effluent obtained at the end of the step (a) of hydrotreatment in a fixed bed undergoes at least one separation step, possibly completed by additional separation steps, making it possible to separate at least one light fraction and at least one less a heavy fraction. By "light fraction" is meant a fraction in which at least 90% of the compounds have a boiling point below 350 ° C.

By "heavy fraction" is meant a fraction in which at least 90% of the compounds have a boiling point greater than or equal to 350 ° C. Preferably, the light fraction obtained during the separation step (b) comprises a gaseous phase and at least a light fraction of hydrocarbons of the naphtha, kerosene and / or diesel type. The heavy fraction preferably comprises a vacuum distillate fraction and a vacuum residue fraction and / or an atmospheric residue fraction.

The step (b) of separation can be implemented by any method known to those skilled in the art. This method can be selected from high or low pressure separation, high or low pressure distillation, high or low pressure stripping, liquid / liquid extraction, and combinations of these different methods that can operate at different pressures and temperatures.

According to a first embodiment of the present invention, the effluent from step (a) hydrotreatment undergoes a step (b) separation with decompression. According to this embodiment, the separation is preferably carried out in a fractionation section which may first include a high temperature high pressure separator (HPHT), and optionally a low temperature high pressure separator (HPBT), optionally followed subsequently by an atmospheric distillation section and / or a vacuum distillation section.

Preferably, said heavy fraction can be fractionated by atmospheric distillation into at least one atmospheric distillate fraction, preferably containing at least a light fraction of naphtha, kerosene and / or diesel-type hydrocarbons, and an atmospheric residue fraction. At least a portion of the atmospheric residue fraction can also be fractionated by vacuum distillation into a vacuum distillate fraction, preferably containing vacuum gas oil, and a vacuum residue fraction.

At least a portion of the vacuum residue fraction and / or the atmospheric residue fraction is advantageously sent to the hydrocracking step (c). Part of the gas oil under vacuum, atmospheric residue and / or under vacuum can also be recycled in step (a) hydrotreatment or be withdrawn and sent to the product tanks or to another refining unit (catalytic cracking or hydrocracking of gas oil under vacuum under vacuum for example).

According to a second embodiment, a portion of the effluent from the hydrotreating step (a) undergoes a step (b) of separation without decompression of at least one heavy fraction. According to this embodiment, the effluent of the hydrotreatment step (a) is sent to a separation section, generally in an HPHT separator, having a cutting point between 200 ° C. and 400 ° C., making it possible to obtain at least one light fraction and at least one heavy fraction. In general, the separation is preferably not made according to a precise cutting point, it is rather like a flash type separation.

The heavy fraction can then be directly sent, in admixture with a hydrogen-rich gas, in step (c) of hydrocracking.

The light fraction may undergo other separation steps. Advantageously, it may be subjected to atmospheric distillation to obtain a gaseous fraction, at least a light fraction of liquid hydrocarbons of the naphtha, kerosene and / or diesel type and a vacuum distillate fraction, the latter being at least part sent at least partly in step (c) of hydrocracking. Another part of the vacuum distillate can be used as a fluxing agent for a fuel oil. Another part of the vacuum distillate can be upgraded by being subjected to a hydrocracking step and / or catalytic cracking in a fluidized bed.

Even more advantageously, the light fraction from the HPHT separator can be cooled and then introduced into a low temperature high pressure separator (HPBT) in which a hydrogen-containing gas fraction and a distillate-containing liquid fraction are separated. This liquid fraction containing distillates can be sent to the hydrocracking step c), via a pump, in a mixture with the liquid fraction from the HPHT separator.

Alternatively, this liquid fraction containing distillates can be sent to the final separation step d) which also processes the effluent from the hydrocracking step c). No-decompression separation provides better thermal integration, and saves energy and equipment. In addition, this embodiment has technical and economic advantages since it is not necessary to increase the flow pressure after separation before the subsequent hydrocracking step.

Intermediate fractionation without decompression being simpler than fractionation with decompression, the investment cost is therefore advantageously reduced.

The gaseous fractions resulting from the separation step preferably undergo a purification treatment to recover the hydrogen and recycle it to the hydrotreatment and / or hydrocracking reactors. The presence of the intermediate separation step, between step (a) of hydrotreatment and step (c) of hydrocracking, advantageously makes it possible to have two independent hydrogen circuits, one connected to hydrotreating, the other hydrocracking, and which, if necessary, can be connected to each other.

Hydrogen makeup can be done at the hydrotreatment section, or at the hydrocracking section, or at both.

The recycle hydrogen can supply the hydrotreatment section or the hydrocracking section or both. A compressor may possibly be common to both hydrogen circuits. The fact of being able to connect the two hydrogen circuits makes it possible to optimize the hydrogen management and to limit investments in terms of compressors and / or purification units of the gaseous effluents.

The various embodiments of the hydrogen management that can be used in the present invention are described in the application for FR 2957607 .

The light fraction obtained at the end of the separation step (b), which comprises hydrocarbons of the naphtha, kerosene and / or diesel or other type, in particular LPG and vacuum gas oil, can be recovered according to the methods that are well known. of the skilled person.

The products obtained can be incorporated into fuel formulations (also called "pools" fuels according to the English terminology), or undergo additional refining steps. The fraction (s) naphtha, kerosene, gas oil and vacuum gas oil may be subjected to one or more treatments, for example hydrotreatment, hydrocracking, alkylation, isomerization, catalytic reforming, catalytic or thermal cracking, to bring them in a controlled manner. separated or in mixture, to the required specifications which may relate to the sulfur content, the smoke point, the octane number, cetane, and others.

Step c) Hydrocracking

• zone d'hydrocraquage comprenant un réacteur en lit bouillonnant suivi d'un réacteur en lit hybride,
• zone d'hydrocraquage comprenant un réacteur en lit hybride suivi d'un réacteur en lit hybride,
• zone d'hydrocraquage comprenant un seul réacteur en lit hybride.

At least one heavy fraction from the separation step b) is mixed with a hydrogen-rich gas. This mixture feeds the hybrid bed hydrocracking section. The hybrid bed hydrocracking section can be divided into three variants:

• hydrocracking zone comprising a bubbling bed reactor followed by a hybrid bed reactor,
• hydrocracking zone comprising a hybrid bed reactor followed by a hybrid bed reactor,
• hydrocracking zone comprising a single hybrid bed reactor.

In the variants comprising two reactors, between two hydrocracking reactors, at least one inter-stage separator for separating a gas fraction and a liquid fraction, can be installed so as to send to the second reactor only the liquid fraction from the separator interstage.

The "disperse" catalyst that occurs in the hybrid bed reactor is a sulfide catalyst preferably containing at least one member selected from the group consisting of Mo, Fe, Ni, W, Co, V, Ru. These catalysts are generally monometallic or bimetallic (by combining, for example, a non-noble group VIIIB element (Co, Ni, Fe) and a group VIB element (Mo, W) .The catalysts used may be heterogeneous solid powders ( such as natural ores, iron sulphate, etc.), dispersed catalysts derived from water-soluble precursors such as phosphomolybdic acid, ammonium molybdate, or a mixture of Mo or Ni oxide. with aqueous ammonia.

Preferably, the catalysts used are derived from soluble precursors in an organic phase (oil-soluble catalysts).

The precursors are organometallic compounds such as the naphthenates of Mo, Co, Fe, or Ni, or the Mo octoates, or the multi-carbonyl compounds of these metals, for example 2-ethyl hexanoates of Mo or Ni, acetylacetonates of Mo or Ni, C7-C12 fatty acid salts of Mo or W, etc. They can be used in the presence of a surfactant to improve the dispersion of metals, when the catalyst is bimetallic. The catalysts are in the form of dispersed particles, colloidal or otherwise depending on the nature of the catalyst. Such precursors and catalysts that can be used in the process according to the invention are widely described in the literature.

In general, the catalysts are prepared before being injected into the feed. The preparation process is adapted according to the state in which the precursor is and of its nature. In all cases, the precursor is sulfided (ex-situ or in-situ) to form the catalyst dispersed in the feedstock.

For the preferred case of so-called oil-soluble catalysts, in a typical process, the precursor is mixed with a carbonaceous feedstock (which may be part of the feedstock to be treated, an external feedstock, a recycled fraction, etc.). the mixture is then sulphurized by adding a sulfur compound (preferred hydrogen sulphide or optionally an organic sulphide such as DMDS in the presence of hydrogen) and heated. The preparations of these catalysts are described in the literature. The "dispersed" catalyst particles as defined above (powders of metallic mineral compounds or of precursors soluble in water or in oil) generally have a size of between 1 nanometer and 150 microns, preferably between 0.1 and 100 microns, and even more preferably between 10 and 80 microns. The content of catalytic compounds (expressed as weight percentage of metal elements of group VIII and / or of group VIB) is between 0 and 10% by weight, preferably between 0 and 1% by weight.

Additives may be added during the preparation of the dispersed catalyst or the dispersed catalyst before it is injected into the reactor. These additives are described in the literature. The preferred solid additives are inorganic oxides such as alumina, silica, mixed Al / Si oxides, supported spent catalysts (for example, on alumina and / or silica) containing at least one group VIII element (such as Ni, Co) and / or at least one group VIB element (such as Mo, W). For example, the catalysts described in the application US2008 / 177124 . Carbonaceous solids with a low hydrogen content (for example 4% hydrogen) such as coke or milled activated carbon, optionally pretreated, may also be used. Mixtures of such additives can also be used. The particle size of the additive is generally between 10 and 750 microns, preferably between 100 and 600 microns. The content of any solid additive present at the inlet of the hydrocracking reaction zone in a hybrid bed is between 0 and 10 wt.%, Preferably between 1 and 3 wt.%, And the content of catalytic compounds (expressed as a percentage wt. Group VIII and / or Group VIB metal elements are from 0 to 10% by weight, preferably from 0 to 1% by weight.

The hybrid bed reactor (s) used in the hydrocracking zone therefore consist of two populations of catalysts, a first population using supported catalysts in the form of extrudates whose diameter is advantageously between 0.8 and 1.2 mm. , generally equal to 0.9 mm or 1.1 mm and a second population of "dispersed" type catalyst discussed above.

The fluidization of the catalyst particles in the bubbling bed is enabled by the use of a boiling pump which allows a recycle of liquid, generally inside the reactor. The flow rate of liquid recycled by the boiling pump is adjusted so that the catalyst particles are fluidized but not transported, so that these particles remain in the bubbling bed reactor (with the exception of fine catalysts that can be formed by attrition and trained with the liquid since these fines are small).

For the bubbling bed reactor, use may be made of a conventional granular hydrocracking catalyst, generally an extrudate, comprising, on an amorphous support, at least one metal or metal compound having a hydro-dehydrogenating function.

This catalyst may be a catalyst comprising Group VIII metals, for example nickel and / or cobalt, most often in combination with at least one Group VIB metal, for example molybdenum and / or tungsten. For example, a catalyst comprising from 0.5% to 10% by weight of nickel and preferably from 1% to 5% by weight of nickel (expressed as nickel oxide NiO) and from 1% to 30% by weight may be used. molybdenum, preferably from 5% to 20% by weight of molybdenum (expressed as molybdenum oxide MoO3) on an amorphous mineral support.

This support may for example be chosen from the group consisting of alumina, silica, silica-aluminas, magnesia, clays and mixtures of at least two of these minerals. This support may also contain other compounds and for example oxides selected from the group consisting of boron oxide, zirconia, titanium oxide, phosphoric anhydride. Most often an alumina support is used and very often a support of alumina doped with phosphorus and possibly boron.

When phosphorus pentoxide P2O5 is present, its concentration is usually less than 20% by weight and most often less than 10% by weight. When B2O3 boron trioxide is present, its concentration is usually less than 10% by weight. The alumina used is usually a y (gamma) or η (eta) alumina. This catalyst may be in the form of extrudates. The total content of metal oxides of groups VI and VIII may be between 5% and 40% by weight, preferably between 7% and 30% by weight, and the weight ratio expressed as metal oxide between metal (or metals) of group VI on metal (or metals) of group VIII is between 20 and 1, preferably between 10 and 2.

The spent catalyst may be partly replaced by fresh catalyst, generally by withdrawing from the bottom of the reactor and introducing the fresh or new catalyst at the top of the reactor at a regular time interval, that is to say, for example by puff or continuously or almost continuously. The catalyst can also be introduced from below and withdrawn from the top of the reactor. For example, fresh catalyst can be introduced every day. The replacement rate of spent catalyst with fresh catalyst may be, for example, from about 0.05 kilograms to about 10 kilograms per cubic meter of charge.

This withdrawal and this replacement are performed using devices allowing the continuous operation of this hydrocracking step. The hydrocracking reactor usually comprises a recirculation pump for maintaining the catalyst in a bubbling bed by continuous recycling of at least a portion of the liquid withdrawn at the top of the reactor and reinjected at the bottom of the reactor. It is also possible to send the spent catalyst withdrawn from the reactor into a regeneration zone in which the carbon and the sulfur contained therein are eliminated before it is reinjected in the hydrocracking step c). For a reactor operating in a bubbling bed during step c) of hydrocracking, its implementation may be similar to that of the H-OIL® process as described, for example, in the US Patent 6270654 .

• une pression partielle d'hydrogène variant de 2 à 35 MPa et préférentiellement de 10 à 25 MPa,
• une température comprise entre 330°C et 550°C, de préférence de 350°C à 500°C, encore plus préférentiellement entre 370°C et 480°C,
• une vitesse spatiale horaire "réacteur" (VVH réacteur, soit ratio entre le débit volumique de charge et le volume de réacteur) comprise entre 0,1 et 10 h-1, de préférence de 0,1 h à 5 h-1 et de manière plus préférée entre 0,1 et 2 h-1,
• une vitesse spatiale horaire "catalyseurs lit bouillonnant" pour les réacteurs lit bouillonnant ou hybride (VVH "catalyseurs lit bouillonnant", soit le ratio entre le débit volumique de charge en Sm3/h et le volume en m3 de catalyseurs lit bouillonnant au repos, lorsque le taux d'expansion du lit bouillonnant est nul) comprise entre 0,1 et 5 h-1, de préférence de 0,1 h à 3 h-1 et de manière plus préférée entre 0,1 et 1 h-1,
• une teneur en composés catalytiques dans les catalyseurs "dispersés" pour les réacteurs en lit hybride (exprimée en pourcentage poids d'éléments métalliques du groupe VIII et/ou du groupe VIB) comprise entre 0 et 10% pds, de préférence entre 0 et 1% pds
• un rapport hydrogène/charge compris entre 50 et 5000 Nm3/m3, le plus souvent d'environ 100 à environ 1500 Nm3/m3, avec une gamme préférée entre 500 et 1300 Nm3/m3.

Whatever the configuration of the hydrocracking zone, the operating conditions of the hydrocracking zone are in general the following:

• a hydrogen partial pressure ranging from 2 to 35 MPa and preferably from 10 to 25 MPa,
• a temperature of between 330 ° C. and 550 ° C., preferably of 350 ° C. to 500 ° C., even more preferentially of between 370 ° C. and 480 ° C.,
• a reactor hourly space velocity (VVH reactor, ie ratio between the charge volume flow rate and the reactor volume) of between 0.1 and 10 h -1, preferably from 0.1 h to 5 h -1, and more preferably between 0.1 and 2 h -1,
• an hourly space velocity "bubbling bed catalysts" for bubbling or hybrid bed reactors (VVH "bubbling bed catalysts", ie the ratio between the flow rate of charge at Sm3 / h and the volume in m3 of bubbling bed catalysts at rest, when the expansion rate of the boiling bed is zero) of between 0.1 and 5 h -1, preferably of 0.1 hr to 3 h -1 and more preferably between 0.1 and 1 h -1,
• a content of catalytic compounds in the "dispersed" catalysts for the hybrid bed reactors (expressed as a percentage by weight of metal elements of group VIII and / or of group VIB) of between 0 and 10% by weight, preferably between 0 and 1 % wt
• a hydrogen / charge ratio of between 50 and 5000 Nm3 / m3, most often from about 100 to about 1500 Nm3 / m3, with a preferred range of 500 to 1300 Nm3 / m3.

The operating conditions of the hydrocracking zone in at least one reactor containing a "dispersed" catalyst coupled with the fact that the feedstock was previously hydrotreated in step a) of hydrotreatment, then separated in step b) of separation , allow to obtain conversion rates of between 30 and 100%, preferably between 40 and 80% and hydrodesulphurization rates between 70 and 100%, preferably between 85 and 99%.

The conversion ratio mentioned above is defined as the amount of compounds having a boiling point greater than 520 ° C in the initial hydrocarbon feedstock, minus the amount of compounds having a boiling point higher than 520 ° C in the hydrocarbon effluent obtained at the end of the hydrocracking step c), all divided by the amount of compounds having a boiling point greater than 520 ° C. in the initial hydrocarbon feedstock. A high conversion rate is advantageous to the extent that this conversion rate illustrates the production of conversion products, mainly atmospheric distillates and / or vacuum distillates of the naphtha, kerosene and diesel type, in a significant amount.

The hydrodesulphurization rate mentioned above is defined as the amount of sulfur in the initial hydrocarbon feedstock, minus the amount of sulfur in the hydrocarbon effluent obtained at the end of the hydrocracking step c), the whole divided by the amount of sulfur in the initial hydrocarbon feed.

Step d) separating the hydrocracking effluent

The process according to the invention comprises a step d) of separation make it possible to obtain at least one gaseous fraction and at least one liquid hydrocarbon fraction. The effluent obtained at the end of the hydrocracking step c) comprises a liquid fraction and a gaseous fraction containing the gases, in particular H 2, H 2 S, NH 3, and C 1 -C 4 hydrocarbons. This gaseous fraction can be separated from the hydrocarbon effluent by means of separating devices well known to those skilled in the art, in particular by means of one or more separator flasks that can operate at different pressures and temperatures, possibly associated with each other. steam or hydrogen stripping means, and generally one or more distillation columns.

The effluent obtained at the end of the hydrocracking step c) is advantageously separated in at least one separator flask into at least one gaseous fraction and at least one liquid fraction. These separators may, for example, be high temperature high pressure separators (HPHT) and / or low temperature high pressure separators (HPBT).

After a possible cooling, this gaseous fraction is preferably treated in a hydrogen purification means so as to recover the hydrogen that is not consumed during the hydrotreatment and hydrocracking reactions.

The hydrogen purification means may be an amine wash, a membrane, a PSA (pressure swing adsorption) system, or a plurality of these means arranged in series. The purified hydrogen can then advantageously be recycled in the process according to the invention, after possible recompression. The hydrogen may be introduced at the inlet of the hydrotreatment step (a) and / or at different locations during the hydrotreatment stage and / or at the inlet of the hydrocracking step (c). and / or at different locations during step c) of hydrocracking.

The separation step d) may also comprise a steam or hydrogen stripping step, generally with steam, in order to remove at least one gas fraction rich in hydrogen sulfide (H2S).

The separation step d) may also comprise atmospheric distillation and / or vacuum distillation. Advantageously, the separation step (d) further comprises at least one atmospheric distillation, in which the liquid hydrocarbon fraction (s) obtained after separation is (are) fractionated (s). by atmospheric distillation into at least one atmospheric distillate fraction and at least one atmospheric residue fraction.

The atmospheric distillate fraction may contain commercially recoverable fuels bases (naphtha, kerosene and / or diesel), for example in the refinery for the production of motor and aviation fuels.

In addition, the separation step (d) of the process according to the invention may advantageously also comprise at least one vacuum distillation in which the liquid hydrocarbon fraction (s) obtained (s) after separation and / or the atmospheric residue fraction obtained after atmospheric distillation is (are) fractionated by vacuum distillation into at least one vacuum distillate fraction and at least one vacuum residue fraction.

The step d) of separation of the effluent resulting from the hydrocracking step can be carried out either in a summary manner, allowing one or two liquid fractions to be obtained, or in a more complete manner and making it possible to obtain at least three liquid fractions. The separation d) carried out in a more complete manner thus makes it possible to obtain distillate atmospheric and / or well separated vacuum cuts (naphthta, kerosen, gas oil, vacuum gas oil, for example) from the atmospheric residue and / or under vacuum. The manner in which this separation step is performed conditions the continuation of the optional steps e) and f).

According to a first embodiment corresponding to a rather complete separation, the separation step (d) comprises a hot high pressure flask, a high pressure cold flask, a low pressure hot flask, a low pressure cold flask, and then a flask. liquid from separator flasks, an atmospheric distillation, in which the liquid hydrocarbon fraction (s) obtained (s) obtained after separation is (are) fractionated by atmospheric distillation into at least one distillate fraction atmospheric residue and then a vacuum distillation in which the residue fraction atmospheric obtained after atmospheric distillation is fractionated by vacuum distillation into at least one vacuum distillate fraction and at least one vacuum residue fraction. The vacuum distillate fraction typically contains vacuum gas oil fractions. At least a portion of the atmospheric residue fraction and / or the vacuum distillate fraction, and / or the vacuum residue fraction, can be recycled in the hydrocracking step c) or in the hydrotreatment step a) or be sent to product tanks or be treated in another refining unit (catalytic cracking or vacuum distillate hydrocracking, for example).

According to a second embodiment corresponding to a summary separation, the separation step (d) comprises a hot high pressure flask, a high pressure cold flask, a low pressure hot flask, a low pressure cold flask and then a liquid fraction. from the separator flasks, a steam stripping column for removing at least one light fraction rich in hydrogen sulfide. This second embodiment may be advantageous during the implementation of the optional steps e) treatment of sediments and catalyst residues and f) separation of the liquid fraction from step d). Thus, the distillation columns of step f) are less prone to fouling since they treat a liquid fraction whose sediment content was reduced during step e). It is therefore advantageous to carry out step d) in a summary manner by using a minimum of equipment that processes a hydrocarbon fraction that may contain sediments.

At the end of the separation step (d), at least one liquid hydrocarbon fraction with a sulfur content of less than or equal to 0.5% by weight, preferably less than or equal to 0.3% by weight, is obtained. and more preferably less than or equal to 0.1% by weight. This liquid hydrocarbon fraction can advantageously be used as a base of fuel oil or as fuel oil, especially as a base of bunker oil or as fuel oil, with low sulfur content meeting the new recommendations of the International Maritime Organization. Advantageously, all of the liquid hydrocarbon effluent obtained at the end of the separation step (d) may have a sulfur content of less than or equal to 0.5% by weight, and preferably less than or equal to 0.3. % in weight.

This liquid hydrocarbon effluent may, at least in part, advantageously be used as fuel oil bases or as fuel oil, especially as a fuel oil base or as bunker oil with low sulfur content meeting the new recommendations of the International Maritime Organization.

By "fuel" is meant in the invention a hydrocarbon feedstock used as fuel. By "oil base" is meant in the invention a hydrocarbon feed which, mixed with other bases, constitutes a fuel oil. Depending on the origin of these bases, in particular depending on the type of crude oil and the type of refining, the properties of these bases, in particular their sulfur content and their viscosity, are very diverse.

One of the interests of the sequence of a hydrotreatment in a fixed bed and then a hydrocracking in at least one reactor containing a "dispersed" catalyst lies in the fact that the charge of the hybrid bed hydrocracking reactor is already at least partially hydrotreated. In this way, it is possible to obtain equivalent conversion of hydrocarbon effluents of better quality, in particular with lower sulfur contents. In addition, the supported and dispersed catalyst consumption in the hybrid bed hydrocracking step is greatly reduced compared to a process without prior fixed bed hydrotreatment.

Step e) sediment treatment

The hydrocarbon effluent obtained at the end of step d) of separation of the hydrocracking effluent, and in particular the heavier liquid fraction obtained, generally a fraction of the atmospheric residue or vacuum residue type, may contain sediments and catalyst residues. At least a portion of the sediments may consist of precipitated asphaltenes resulting from a hydrocracking of a petroleum residue feed.

The catalyst residues may be fines resulting from the attrition of extruded type catalysts in the implementation of a bubbling bed hydrocracking reactor. The phenomenon of attrition of extruded type catalysts can also be in a hybrid bed. Another part of the catalyst residues comes from the "dispersed" catalyst.

In order to obtain a fuel oil or a fuel base that meets the recommendations of a sediment content after aging (IP390) less than or equal to 0.1%, the process according to the invention may comprise an additional step of separating the sediments. and the catalyst residues of the liquid hydrocarbon effluent after step d) of separation.

Depending on the hydrocracking conditions, the sediment content in the heavy fraction varies. From an analytical point of view, existing sediments (IP375) and sediments after aging (IP390) that include potential sediments. Depending on the hydrocracking conditions, it may therefore be necessary to carry out, during step e) of sediment treatment, a maturation stage upstream of the solid-liquid separation techniques mentioned above. This maturation step converts potential sediments into existing sediments so that all existing sediments after treatment can be separated more efficiently and thus meet, after treatment, the sediment content after aging (IP390) of 0.1%. max. The maturation step consists in applying a residence time of between 1 and 1500 minutes, preferably between 30 and 300 minutes, more preferably between 60 and 180 minutes, to the heavy fraction previously heated to a temperature between 100 and 500 ° C. C, preferably between 150 and 350 ° C, and more preferably between 200 and 300 ° C.

The pressure of the maturation stage is less than 200 bar, preferably less than 100 bar, more preferably less than 30 bar, and even more preferably less than 15 bar.

This maturation step can be done, for example with an exchanger or a heating furnace and then one or more capacity (s) in series or in parallel such (s) as a horizontal or vertical balloon, optionally with a decanting function for remove some of the heavier solids, and / or a piston reactor. A stirred and heated tank may also be used, and may optionally be bottom tapped to remove some of the heavier solids. Optionally, the maturation step can be carried out in the presence of an inert gas (nitrogen for example) or oxidizing (oxygen, air or air depleted by nitrogen). The use of an oxidizing gas accelerates the maturation process. According to this option, there is therefore introduction of a gas in mixture with the liquid fraction resulting from step d) before the maturation and separation of this gas after maturation so as to obtain a liquid fraction at the end of the step maturation and sent to the step of physical separation of sediments.

One of the challenges of using "disperse" catalysts in hydrocracking processes is the cost of this "dispersed" catalyst. The present invention limits the cost of hydrocracking catalysts due to the upstream hydrotreatment step. It may, however, be advantageous to at least partially recover the "dispersed" catalyst present in the heavy cuts. This step of recovering the "dispersed" catalyst can therefore be performed consecutively or simultaneously at the step of separating sediments and catalyst residues.

The method according to the invention may therefore further comprise a treatment step e) allowing the separation of sediments and catalyst residues, optionally coupled simultaneously or consecutively, to a "dispersed" catalyst recovery step. During this step e), at least a portion of the atmospheric residue and / or vacuum residue fractions are subjected to a separation of sediments and catalyst residues, optionally coupled simultaneously or consecutively, to a catalyst recovery step. dispersed ", using in step e), after the maturation to convert the potential sediments into existing sediments, at least one filter, a separation on membranes, a bed of organic or inorganic type filtering solids, an electrostatic precipitation , a centrifuge system, in-line decantation, auger withdrawal. Step e) sediment treatment is a clever coupling of a first stage of maturation to convert potential sediments into existing sediments and a second stage of physical separation solid-liquid to remove at least some of the all existing sediments.

At the end of the sediment treatment step e), at least one liquid hydrocarbon fraction having a sulfur content of less than or equal to 0.5% by weight, preferably less than or equal to 0.3% by weight, is obtained. and more preferably less than or equal to 0.1% by weight. In addition, the liquid hydrocarbon fraction from sediment treatment step e) is characterized by a sediment content after aging (IP390) of less than 0.1% by weight.

This liquid hydrocarbon fraction can advantageously be used as a fuel oil base or as fuel oil, especially as a bunker oil or bunker fuel oil base, with low sulfur content and low sediment content after aging in accordance with the new recommendations of the Maritime Organization. International and ISO8217 standard for marine fuels.

Advantageously, all the liquid hydrocarbon effluent obtained at the end of the sediment treatment step e) has a sulfur content of less than or equal to 0.5% by weight, and preferably less than or equal to 0.3. % in weight.

Advantageously, all of the liquid hydrocarbon effluent obtained at the end of the sediment treatment step e) has a sediment content after aging (IP390) of less than 0.1% by weight.

Step f) separating the effluent from the sediment treatment stage

The method according to the invention comprises a step f) of separation make it possible to obtain at least one liquid hydrocarbon fraction. The effluent obtained at the end of step d) of sediment treatment comprises at least one liquid fraction. The composition of this liquid fraction depends on the manner in which the step d) of separation of the hydrocracking effluent has been carried out. If step d) has been carried out in a summary manner, the effluent from step e) therefore contains a mixture of distillates and residues that must be separated in order to valorize each of the cuts, by putting into effect at least one distillation column. If step d) was conducted more completely, only a liquid fraction of the vacuum residue type and / or atmospheric residue was sent to the sediment treatment step e). In the case of a d) more complete separation, the liquid fraction from step e) may therefore not require an optional step f).

We will not take over all separation equipment that can be implemented during the f) separation step since they are well known to those skilled in the art and already mentioned in steps b) and d) separations ( separator balloons, columns, etc.)

At the end of the separation step (f), at least one liquid hydrocarbon fraction having a sulfur content of less than or equal to 0.5% by weight, preferably less than or equal to 0.3% by weight, is obtained. and more preferably less than or equal to 0.1% by weight. In addition, the liquid hydrocarbon fraction from the separation step f) is characterized by a sediment content after aging (IP390) of less than 0.1% by weight.

This liquid hydrocarbon fraction can advantageously be used as a base of fuel oil or as fuel oil, especially as a bunker oil or bunker fuel oil base, with low sulfur content and low sediment content after aging in accordance with the new recommendations of the Maritime Organization. International and ISO8217 standard for marine fuels.

By "fuel" is meant in the invention a hydrocarbon feedstock used as fuel. By "oil base" is meant in the invention a hydrocarbon feed which, mixed with other bases, constitutes a fuel oil. Depending on the origin of these bases, in particular depending on the type of crude oil and the type of refining, the properties of these bases, in particular their sulfur content and their viscosity, are very diverse.

DETAILED DESCRIPTION OF THE FIGURES

The figure 1 represents a process according to the invention with intermediate separation with decompression. The introduction of the feedstock (10) to the outlet of the effluent (42) represents the hydrotreatment zone and this zone is described briefly because it can know many variants known to those skilled in the art.

• une première étape (étape i) au cours de laquelle la charge traverse successivement le réacteur Ra, puis le réacteur Rb,
• une deuxième étape (étape ii) au cours de laquelle la charge traverse uniquement le réacteur Rb, le réacteur Ra étant court-circuité pour régénération et/ou remplacement du catalyseur,
• une troisième étape (étape iii) au cours de laquelle la charge traverse successivement le réacteur Rb, puis le réacteur Ra,
• une quatrième étape (étape iv) au cours de laquelle la charge traverse uniquement le réacteur Ra, le réacteur Rb étant court-circuité pour régénération et/ou remplacement du catalyseur. Le cycle peut ensuite recommencer.

In the figure 1 the charge (10), preheated in the chamber (12), mixed with recycled hydrogen (14) and makeup hydrogen (24) preheated in the chamber (16), is introduced by the conduct (18) in the guard zone represented by the two reactors Ra and Rb. These reactors are generally reactive reactors in the sense that they operate according to a series of cycles each comprising four successive stages:

• a first step (step i) during which the charge passes successively through the reactor Ra and then the reactor Rb,
• a second step (step ii) during which the feed passes only through the reactor Rb, the reactor Ra being short-circuited for regeneration and / or replacement of the catalyst,
• a third step (step iii) during which the charge passes successively through the reactor Rb and then the reactor Ra,
• a fourth step (step iv) in which the feed passes only through the reactor Ra, the reactor Rb being short-circuited for regeneration and / or replacement of the catalyst. The cycle can then start again.

Returning to figure 1 the effluent leaving the at least one guard reactor (Ra, Rb) is optionally remixed with hydrogen arriving via line (65) into an HDM reactor (32) containing a fixed bed of catalyst. For readability reasons, a single HDM reactor (32) and a single HDS reactor (38) are shown in the figure, but the HDM and HDS section may include multiple HDM and HDM reactors. 'HDS in series. The effluent from the HDM reactor is withdrawn through line (34) and sent to the first HDS reactor (38) where it passes through a fixed bed of catalyst.

The effluent from the hydrotreatment stage is sent via line (42) into a high temperature high pressure separator (HPHT) (44) from which a gaseous fraction (46) and a liquid fraction (48) are recovered. . The cutting point is usually between 200 and 400 ° C. The gaseous fraction (46) is sent, generally via an exchanger (not shown) or an air cooler (50) for cooling to a low temperature high pressure separator (HPBT) (52) from which a gaseous fraction (54) containing gases (H2, H2S, NH3, C1-C4 hydrocarbons, ...) and a liquid fraction (56).

The gaseous fraction (54) from the low temperature high pressure separator (HPBT) (52) is treated in the hydrogen purification unit (58) from which the hydrogen (60) is recovered for recycling via the compressor (62) and the line (65) to the reactors (32) and / or (38) or via the line (14) to the permutable reactors (Ra, Rb).

Gases containing undesirable nitrogen and sulfur compounds are removed from the plant (stream (66)).

The liquid fraction (56) from the low temperature high pressure separator (HPBT) (52) is expanded in the device (68) and sent to the fractionation system (70). Optionally, a medium pressure separator (not shown) after the expander (68) can be installed to recover a gaseous fraction that is sent to the purification unit (58), and a liquid phase that is fed to the fractionation section (58). 70).

The liquid fraction (48) from the high temperature high pressure separator (HPHT) (44) is expanded in the device (72) and sent to the fractionation system (70).

Fractions (56) and (48) can be sent together, after expansion, to the fractionation (70).

The fractionation system (70) comprises an atmospheric distillation system for producing a gaseous effluent (74), at least a so-called light fraction (76) and in particular containing naphtha, kerosene and diesel and an atmospheric residue fraction (78) . Part of the atmospheric residue fraction can be sent via the line (80) into the hydrocracking reactors (98, 102).

All or part of the atmospheric residue fraction (78) is sent to a vacuum distillation column (82) to recover a fraction (84) containing the vacuum residue and a vacuum distillate fraction (86) containing vacuum gas oil.

The vacuum residue fraction (84), optionally mixed with a portion of the atmospheric residue fraction (80) and / or with a portion of the vacuum distillate fraction (86), is mixed with optionally recycled hydrogen (88). supplemented with makeup hydrogen (90) preheated in the furnace (91). It optionally passes through an oven (92).

Optionally, a co-charge (94) may be introduced.

The heavy fraction is then introduced via line (96) into the hydrocracking step at the bottom of the first hybrid bed reactor (98) operating at an upward flow of liquid and gas and containing at least one type hydrocracking catalyst. "Dispersed" and a supported catalyst. Recall that in the context of the present invention, a hybrid bed is a bubbling bed which contains a supported catalyst which has been added a "dispersed" catalyst.

The "dispersed" type catalyst is introduced via line (100) upstream of the first hydrocracking reactor (98). Optionally, the converted effluent (104) from the reactor (98) may be separated from the light fraction (106) in an inter-stage separator (108).

All or part of the effluent (110) from the inter-stage separator (108) is advantageously mixed with additional hydrogen (157), if necessary preheated (not shown).

This mixture is then injected by the pipe (112) into a second hydrocracking reactor (102) also in a hybrid bed operating at an upward flow of liquid and gas containing at least one "dispersed" hydrocracking catalyst and a catalyst. supported.

This "dispersed" type catalyst was injected upstream of the first reactor (98), but a booster upstream of the second reactor (102) could also be achieved via a conduit not shown.

The operating conditions, in particular the temperature, in this reactor are chosen to reach the desired conversion level, as previously described. The hydrocracking reactor effluent is fed through line (134) into a high temperature high pressure (HPHT) separator (136) from which a gaseous fraction (138) and a liquid fraction (140) are recovered.

The gaseous fraction (138) is generally sent via an exchanger (not shown) or a dry cooler (142) for cooling to a low temperature high pressure separator (HPBT) (144) from which a gaseous fraction (146) containing the gases (H2, H2S, NH3, C1-C4 hydrocarbons ...) and a liquid fraction (148) is recovered.

The gaseous fraction (146) of the low temperature high pressure separator (HPBT) (144) is treated in the hydrogen purification unit (150) from which hydrogen (152) is recovered for recycling via the compressor. (154) and line (156) and / or line (157) to the hydrocracking section.

The hydrogen purification unit may consist of an amine wash, a membrane, a PSA type system.

The gases containing undesirable nitrogen and sulfur compounds are removed from the installation (stream (158) which may represent several streams, in particular a flow rich in H2S and one or more purges containing light hydrocarbons (C1 and C2) which can (can ) be used in refinery fuel gas).

The liquid fraction (148) of the low temperature high pressure separator (HPBT) (144) is expanded in the device (160) and sent to the fractionation system (172).

Optionally, a medium pressure separator (not shown) after the expander (160) can be installed to recover a vapor phase that is sent to the purification unit (150) and / or a dedicated medium pressure purification unit (not shown). ), and a liquid phase which is fed to the fractionation section (172).

The liquid fraction (140) from the high temperature high pressure separation (HPHT) (136) is expanded in the device (174) and sent to the fractionation system (172). Optionally, a medium pressure separator (not shown) after the expander (174) can be installed to recover a vapor phase that is sent to the purification unit (150) and / or a dedicated medium pressure purification unit (not shown ), and a liquid phase which is fed to the fractionation section (172).

Of course, the fractions (148) and (140) can be sent together, after expansion, to the system (172). The fractionation system (172) comprises an atmospheric distillation system for producing a gaseous effluent (176), at least a so-called light fraction (178), containing in particular naphtha, kerosene and diesel, and an atmospheric residue fraction (180). ).

Part of the atmospheric residue fraction (180) can be withdrawn via line (182) to form a desired fuel oil base. All or part of the atmospheric residue fraction (180) can be sent to a vacuum distillation column (184) to recover a fraction containing the vacuum residue (186) and a vacuum distillate fraction (188) containing vacuum gas oil. Optionally, the atmospheric residue fraction (182) and / or the vacuum residue fraction (186) may be subjected to a step of treatment and separation of sediments and catalyst residues.

A heavy fraction of the atmospheric residue type (182) is optionally preheated in an oven or exchanger (205) so as to reach the temperature necessary for the maturation (conversion of the potential sediments into existing sediments) which takes place in the capacity (207). . The purpose of the capacity (207) is to provide a residence time necessary for maturation, it can therefore be a horizontal or vertical flask, a buffer tank, a stirred tank or a reactor piston. The heating function can be integrated with the capacity in the case of a stirred stirred tank according to an embodiment not shown. The capacity (207) may also allow settling so as to evacuate a portion of the solids (208). The maturing stream (209) is then subjected to solid-liquid separation (191) to obtain a sediment-reduced fraction (212) and a sediment-rich fraction (211). Similarly, a vacuum residue heavy fraction (186) is optionally preheated in an oven or exchanger (213) so as to reach the temperature necessary for the maturation which takes place in the capacity (215). The purpose of the capacity (215) is to provide a residence time necessary for maturation, it can therefore be a horizontal or vertical flask, a buffer tank, a stirred tank or a reactor piston. The heating function can be integrated with the capacity in the case of a stirred stirred tank according to an embodiment not shown. The capacity (215) may also allow settling so as to evacuate a portion of the solids (216). The maturation stream (217) is then subjected to a solid-liquid separation (192) to obtain a sediment-reduced fraction (219) and a sediment-rich fraction (218).

According to a mode not shown, the maturation devices (207) and (215) can operate in the presence of a gas, in particular an oxidizing gas.

According to a mode not shown, it is also possible to perform a step of treatment and separation of sediments and catalyst residues on a heavy fraction from the effluent separation step, for example on a heavy cut out a separator, for example on the flow (140) before or after the expansion (174). An advantageous mode, not shown, may consist in operating the step of treating and separating the sediments on the stream recovered at the bottom of a stripping column. When the step of treatment and separation of sediments and catalyst residues is operated upstream of a distillation column, this column is less prone to fouling.

At least a portion of the streams (188) and / or (212) and / or (219) constitutes one or more desired oil bases, in particular bases for low-sulfur bunker fuels. Some of the streams (188) and / or (212) and / or (219), before or after the optional sediment treatment and separation step, may be recycled via line (190) to step hydrocracking, or upstream of the hydrotreating step (line not shown).

The recycling of a vacuum-type gas oil section (188) upstream of the hydrotreatment can make it possible to lower the viscosity of the charge and thus facilitate pumping. Recycling an atmospheric residue type (212) or vacuum residue type (219) cutoff upstream of the hydrotreatment or hydrocracking may make it possible to increase the overall conversion.

The figure 2 represents another method according to the invention with intermediate separation without decompression. It will be described below essentially only the differences between the process according to the figure 2 and the method according to figure 1 the hydrotreatment, hydrocracking and separation stages after hydrocracking (and their reference signs) being moreover strictly identical.

The effluent treated in the hydrotreatment reactors is sent via line (42) into a high temperature high pressure separator (HPHT) (44) from which a lighter fraction (46) and a residual fraction (48) are recovered. . The cutting point between these two fractions is generally between 200 and 450 ° C., and preferably between 250 ° C. and 350 ° C.

The residual fraction (48) is sent directly after a possible passage through an oven (92) in the hydrocracking section.

The lighter fraction (46) is sent, generally via an exchanger (not shown) or an air cooler (50) for cooling to a low temperature high pressure separator (HPBT) (52) from which a gaseous fraction is recovered (54). containing the gases (H2, H2S, NH3, C1-C4 hydrocarbons ...) and a liquid fraction (56).

The gaseous fraction (54) of the low temperature high pressure separator (HPBT) (52) is treated in the hydrogen purification unit (58) from which is recovered hydrogen (60) for recycling via the compressor (154) and lines (64) and (156) to the hydrotreating section and / or the hydrocracking section.

Gases containing undesirable nitrogen, sulfur and oxygen compounds are removed from the plant (stream (66)). In this configuration, a single compressor (154) is used to supply all the reactors requiring hydrogen.

The liquid fraction (56) from the low temperature high pressure separator (HPBT) (52) is expanded in the device (68) and sent to the fractionation system (70).

The fractionation system (70) comprises an atmospheric distillation system for producing a gaseous effluent (74), at least a so-called light fraction (76) and containing in particular naphtha, kerosene and diesel and an atmospheric residue fraction (195). . Part of the atmospheric residue fraction can be sent, by means of a pump, not represented, via the line (195) in the hydrocracking reactors (98, 102), whereas another part of the atmospheric residue fraction ( 194) can be sent to another process (hydrocracking or FCC or hydrotreatment).

A variant not shown but close to the diagram of the figure 2 may consist of not using a fractionation system (70) nor to relax the liquid fraction (56) from the cold separator (52). The liquid fraction (56) is then sent to the hydrocracking section optionally by means of a pump mixed with the heavy fraction (48) issuing from the separator (44).

It is not beyond the scope of the invention, that the separation step is with or without decompression, with variants of the hydrocracking section since this hydrocracking section comprises at least one type hydrocracking reactor. hybrid.

• un réacteur d'hydrocraquage de type lit bouillonnant suivi d'un réacteur d'hydrocraquage de type lit hybride
• un réacteur d'hydrocraquage de type lit hybride suivi d'un réacteur d'hydrocraquage de type lit hybride
• un réacteur d'hydrocraquage de type lit hybride seul.

These variations of the invention include in particular for the hydrocracking section instead of the two reactors in hybrid bed (98) and (102):

• a bubbling bed hydrocracking reactor followed by a hybrid bed type hydrocracking reactor
• a hybrid bed type hydrocracking reactor followed by a hybrid bed type hydrocracking reactor
• a hybrid bed type hydrocracking reactor alone.

In the variants relating to the type of hydrocracking reactors described above, it is also possible to intercalate an inter-stage separator allowing the removal of at least one gas fraction between two hydrocracking reactors.

COMPARATIVE EXAMPLE ACCORDING TO THE PRIOR ART AND ACCORDING TO THE INVENTION

The following example illustrates the invention without limiting its scope.

A vacuum residue (RSV Ural) containing 87.0% by weight of compounds boiling at a temperature above 520 ° C, having a density of 9.5 ° API and a sulfur content of 2.72% by weight was treated. weight.

The feedstock was subjected to a fixed bed hydrotreating step a) including two permutable reactors. The operating conditions are given in Table 1. Table 1: Operating conditions of stage a) of hydrotreatment in fixed bed HDM and HDS catalysts NiCoMo on alumina Temperature (° C) 370 H2 partial pressure (MPa) 15 VVH (h-1, Sm3 / h fresh load / m3 fixed bed catalyst) 0.18 H2 / HC inlet section fixed bed excluding H2 consumption (Nm3 / m3 fresh load) 1000

The effluent from the hydrotreating is then subjected to a separation step b) as described in FIG. figure 1 and allowing to recover a gas fraction and a heavy fraction containing a majority of compounds boiling at more than 350 ° C (350 ° C + fraction).

1. a) dans une étape d'hydrocraquage c) comprenant deux réacteurs successifs en lit bouillonnants (non-conforme, selon l'art antérieur).
2. b) dans une étape d'hydrocraquage c) comprenant deux réacteurs successifs en lit bouillonnants avec ajout d'un catalyseur dispersé opérant selon un mode « hybride » (conforme à l'invention).

The heavy fraction (350 ° C + fraction) is then treated according to two schemes:

1. a) in a hydrocracking step c) comprising two successive bubbling bed reactors (non-compliant, according to the prior art).
2. b) in a hydrocracking step c) comprising two successive bubbling bed reactors with addition of a dispersed catalyst operating in a "hybrid" mode (in accordance with the invention).

The operating conditions of hydrocracking step c) are given in Table 2. Table 2: Operational conditions of the hydrocracking section c) in both schemes (a) two bubbling beds, (b) two hybrid bubbling beds (Not Compliant) 2 bubbling beds (Complies) 2 hybrid bubbling beds catalysts NiMo on alumina NiMo on Alumina + Mo Naphenate Temperature R1 (° C) 423 423 Temperature R2 (° C) 431 431 H2 partial pressure (MPa) 13.5 13.5 VVH "reactors" (h-1, Sm3 / h fresh load / m3 of reactors) 0.3 0.3 VVH "bubbling bed catalysts" (h-1, Sm3 / h fresh load / m3 bubbling bed catalysts) 0.6 0.6 "Dispersed" catalyst concentration (ppm precursor in the "hybrid" inlet feedstock) - 100 H2 / HC entry hydrocracking section excluding H2 consumption (Nm3 / m3 fresh load) 600 600

The effluents from the hydrocracking step were then subjected to a separation step d) to separate the gases and liquids by means of separators and atmospheric and vacuum distillation columns.

• une étape de séparation des sédiments et résidus de catalyseurs comportant un filtre poreux métallique de marque Pall® (non-conforme, selon l'art antérieur)
• une étape de traitement des sédiments et résidus de catalyseurs comportant une étape de maturation (4h à 150°C réalisée dans une cuve agitée chauffée en présence d'un mélange air/azote 50/50 sous une pression totale de 0,5 MPa) et de séparation physique des sédiments et résidus de catalyseurs comportant un filtre (conforme à l'invention)

In addition, prior to the vacuum distillation step, the atmospheric residue fraction undergoes a treatment according to 2 variants:

• a step of separating sediments and catalyst residues comprising a Pall® brand metal porous filter (non-compliant, according to the prior art)
• a step of treating sediments and catalyst residues comprising a maturation step (4 hours at 150 ° C. in a stirred tank heated in the presence of a mixture air / nitrogen 50/50 under a total pressure of 0.5 MPa) and physical separation of sediments and catalyst residues comprising a filter (according to the invention)

The yields and the sulfur contents of each fraction obtained in the effluents leaving the global chains are given in Table 3 below: Table 3: Yields and Sulfur Content of Hydrocracking Section Effluent (% w / w) (Non-compliant) a) Fixed bed hydrotreatment + b) Separation + c) Hydrocracking 2 bubbling beds (423/431 ° C) (Complies) a) Hydrotreatment fixed bed + b) separation + c) Hydrocracking 2 hybrid bubbling beds (423/431 ° C) products Yield (% wt) S (% wt) Yield (% wt) S (% wt) NH3 0.7 0 0.7 0 H2S 2.7 94.12 2.7 94.12 C1-C4 (gas) 4.0 0 4.1 0 Naphtha (PI - 150 ° C) 9.3 0.02 9.9 0.02 Diesel (150 ° C - 350 ° C) 24.6 0.05 25.5 0.05 Vacuum distillate (350 ° C - 520 ° C) 31.5 0.28 32.4 0.29 Vacuum residue (520 ° C +) 29.3 0.47 26.7 0.49

It is possible to calculate the conversion rates (difference between the amount of components boiling above 520 ° C in the feedstock and that in the effluent, divided by the amount of feedstock) and the rate of hydrodesulphurization (difference between the amount of sulfur in the feedstock and that in the liquid effluent, divided by that of the feedstock).

Finally, the operating conditions of the hydrocracking step coupled with the different treatment variants (sediment separation with or without treatment) of the heavy phase resulting from the atmospheric distillation have an impact on the stability of the effluents obtained. This is illustrated by the post-aging sediment concentrations measured in the atmospheric residues (350 ° C + cut) after separation or after the sediment treatment step.

The performances of the three treatment schemes are summarized in Table 4 below: Table 4: Summary of process performance according to the prior art and according to the invention (Non compliant) Hydrotreatment fixed bed + separation + Hydrocracking 2 bubbling beds (423/431 ° C) (Complies) Hydrotreatment fixed bed + separation + Hydrocracking 2 hybrid bubbling beds (423/431 ° C) H2 consumption (% w / w) 1.8 2.0 Hydrodesulfurization rate (%) 91 91 Conversion rate (%) 66 69 Treatment No No Yes Separation of sediments Yes Yes Yes Sediment content after aging (IP390) in the 350 ° C + cut from sediment separation 0.4 0.5 <0.1

The results show the significant gain obtained in conversion in the case of the two schemes according to the invention (2 hybrid bubbling beds). These particularly high conversion rates illustrate the production of conversion products (mainly distillates) in a significant amount.

The sediment treatment step e) involving maturation prior to the physical separation of the sediments is essential to form all potential sediments and thus allow their effective separation. Without treatment, beyond a certain level of conversion that leads to many potential sediments, the sediment separation step is not efficient enough for the sediment after aging (IP390) is less than 0.1% by weight, which is the maximum level required for residual type bunkers.

On the other hand, in the case of a less noble application (fuel oil for producing refinery utilities for example), the sediment treatment stage e) may be optional, the sediment content will then be greater than 0.1% by weight.

• coupe 150°C-350°C : 2% en poids du mélange, et
• coupe 350°C-520°C : 41% en poids du mélange, et
• coupe 520°C+ : 57% en poids du mélange.

Subsequently, a mixture is prepared from 350 ° C-520 ° C and 520 ° C + cuts from the sequence a) fixed bed hydrotreatment + b) separation + c) hydrocracking with 2 hybrid bubbling beds + d) effluent separation + e) sediment treatment, in the following proportions:

• cutting 150 ° C-350 ° C: 2% by weight of the mixture, and
• cutting 350 ° C-520 ° C: 41% by weight of the mixture, and
• cutting 520 ° C +: 57% by weight of the mixture.

There was thus obtained a fuel oil having a sulfur content of 0.40% by weight, and having a viscosity of 375 cSt at 50 ° C. In addition, its sediment content after aging is less than 0.1% by weight. In view of these analyzes, this fuel oil is particularly suitable for forming a residual type of fuel oil related to the RMG 380 grade as recommended by the IMO outside the ZESCs by 2020-2025.

In addition to the first mixture leading to a 0.40% sulfur fuel oil, a second mixture consisting of 85% by weight of a fraction from the diesel cut and 15% by weight of a fraction derived from the vacuum distillate cut. In these proportions, the mixture has a sulfur content of 0.08% and a viscosity of 6 cSt at 40 ° C. This mixture thus constitutes a marine fuel of the distillate type ("marine gas oil" or "marine diesel" in the English terminology) which can be likened to the DMB grade (whose viscosity specification is between 2 cSt and 11 cSt at 40 ° C) for example.

Because of its sulfur content of less than 0.1%, this mixture is a fuel of choice for ZCESs by 2015.

Claims (7)

A process for treating a heavy hydrocarbon feedstock having a sulfur content of at least 0.5 wt.%, An initial boiling temperature of at least 350 ° C and a final boiling temperature of at least 450 ° C making it possible to obtain at least one liquid hydrocarbon fraction having a sulfur content of less than or equal to 0.5% by weight, said liquid hydrocarbon fraction being a heavy fuel type fuel which may optionally become a marine fuel, said process comprising successive stages: a) a fixed bed hydrotreatment step, wherein the hydrocarbon feedstock and hydrogen are contacted on a hydrotreatment catalyst, b) a step of separating the effluent obtained at the end of the hydrotreatment step (a) into at least a light fraction and at least one heavy fraction, c) a step of hydrocracking at least a portion of the heavy fraction of the effluent from step (b), taken alone or mixed with other residual or fluxing cuts, in at least one operating reactor in hybrid mode, that is to say operating in a bubbling bed with a supported catalyst associated with a "dispersed" catalyst consisting of very fine catalyst particles constituting a suspension with the hydrocarbon liquid phase to be treated, d) a step of separating the effluent from step (c) to obtain at least one light fraction and at least one heavy fraction, e) a sediment treatment step making it possible to reduce the sediment content of the heavy fraction resulting from the separation step d), f) a final separation step of the effluent of the treatment step e) to obtain said sediment-reduced liquid hydrocarbon fraction (that is to say less than 0.1% by weight). A process for treating a heavy hydrocarbon feedstock according to claim 1, wherein the hydrocracking step is carried out with the following operating conditions: a hydrogen partial pressure ranging from 2 to 35 MPa, and preferentially from 10 to 25 MPa, a temperature of between 330 ° C. and 550 ° C., preferably between 350 ° C. and 500 ° C., more preferably between 370 ° C. and 480 ° C .; a hourly space velocity (VVH reactor, ie ratio between the charge volume flow rate and the reactor volume) of between 0.1 and 10 h -1, preferably from 0.1 h to 5 h -1, and more preferred between 0.1 and 2 h -1, a hourly space velocity "bubbling bed catalysts" for bubbling or hybrid bed reactors between 0.1 and 5 h -1, preferably from 0.1 h to 3 h -1 and more preferably between 0.1 and 1 h-1, the VVH "ebullated bed catalyst being defined as the ratio between the volume flow rate of charge in m3 / h and the volume in m3 of bubbling bed catalyst at rest, that is to say when the rate of expansion of the bubbling bed is void, a content of metal compounds in the catalysts used in a hybrid bed of between 0 and 10 wt.%, preferably between 0 and 1 wt.%, said content being expressed as a percentage by weight of metal elements of group VIII and / or of group VIB , a hydrogen / charge ratio of between 50 and 5000 Nm3 / m3, preferably between 100 and 1500 Nm3 / m3, with a still preferred range between 500 and 1300 Nm3 / m3. A process for treating a heavy hydrocarbon feedstock according to claim 1, wherein the hydrocracking step comprises two reactors, one operating as a bubbling bed, the other as a hybrid bed. Process for the treatment of a heavy hydrocarbon feedstock according to claim 1, in which the hydrocracking step comprises two reactors, the two reactors operating in a hybrid bed. A process for treating a heavy hydrocarbon feedstock according to claim 1, wherein the hydrocracking step comprises a single reactor operating in a hybrid bed. A process for treating a heavy hydrocarbon feedstock according to claim 1, wherein the particles constituting the "disperse" catalyst of the hybrid bed have a size of between 10 and 80 microns. A process for treating a heavy hydrocarbon feedstock according to claim 1, wherein the sediment treatment step e) is carried out on the heavy effluent from the separation step d), said separation step d) being a flash summary separation, and being completed by a final separation step f) downstream of the processing step e).

Images