FR3053356A1 - PROCESS FOR TREATING HEAVY LOADS OF HYDROCARBONS - Google Patents

Abstract

The invention relates to a method for treating a hydrocarbon feed containing asphaltenes, sediments, sulfur, nitrogen and metal impurities in which the feed passes through a filtration section (A) and then a catalytic section (B) located in downstream of the filtration section, the filtration section (A) including at least two stationary filtration units (1, 2) arranged in series, operating in a switchable manner and the catalytic section (B) including at least one catalytic reactor in fixed bed (3, 4), it being understood that the total volume of the fixed filtration beds is between 1% and 50% of the total catalyst volume of the catalytic section. The process involves recycling the catalyst from the catalytic section into the filtration section.

Description

© Publication number: 3,053,356 (to be used only for reproduction orders) © National registration number: 16 56210 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © Int Cl ⁸ : C 10 G 65/04 (2017.01), C10G 31/09, 45/02

A1 PATENT APPLICATION

(© Date of filing: 30.06.16. © Applicant (s): IFP ENERGIES NOUVELLES Etablis- (© Priority: public education - FR. @ Inventor (s): BAZER-BACHI FREDERIC, CHA- TRON-MICHAUD PASCAL, PLAIS CECILE, TELLIER (43) Date of public availability of the ELODIE and WEISS WILFRIED. request: 05.01.18 Bulletin 18/01. (© List of documents cited in the report of preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): IFP ENERGIES NOUVELLES Etablisse- related: public. ©) Extension request (s): © Agent (s): IFP ENERGIES NOUVELLES.

FR 3 053 356 - A1 (34) PROCESS FOR TREATING HEAVY LOADS OF HYDROCARBONS.

The invention relates to a process for treating a charge of hydrocarbons containing asphaltenes, sediments, sulfur, nitrogenous and metallic impurities in which the charge passes through a filtration section (A) then a catalytic section (B). located downstream of the filtration section, the filtration section (A) including at least two fixed bed filtration units (1,2) arranged in series, operating in a permutable manner and the catalytic section (B) including at least one fixed bed catalytic reactor (3, 4), it being understood that the total volume of the fixed filtration beds is between 1% and 50% of the total volume of catalyst in the catalytic section. The process involves recycling the catalyst from the catalytic section to the filtration section.

The present invention relates to a process for the continuous treatment of a hydrocarbon charge containing asphaltenes, sediments, sulfur, nitrogen and metallic impurities using a system which comprises a filtration unit and a catalytic unit arranged downstream of the filtration unit.

State of the art

The objective of catalytic hydrotreatment of heavy loads is both to refine, that is to say to significantly reduce their content of asphaltenes, metals, sulfur and other impurities while improving the hydrogen to carbon ratio (H / C) and while transforming them more or less partially into lighter cuts. The different effluents thus obtained can serve as bases for the production of fuel oil, diesel or petrol, or feedstocks for other units such as the cracking of residues.

One of the problems posed by the catalytic hydrotreatment of these feeds is that impurities can be deposited on the surface and / or in the porosity of the catalyst and / or in the interstices between the grains of catalysts, in the form of metals, in particular sulfides. metals, and coke, tending to quickly deactivate and clog the catalytic system, which requires a shutdown of the installation in order to replace the deactivated catalytic bed.

To be industrially viable, the hydrotreatment processes of this type of feed must therefore be designed so as to allow the longest possible operating cycle without stopping the system. For example, the objective is to reach at least one year of operation, that is to say eleven months minimum of continuous operation with one month maximum stop for the replacement of the whole catalytic system.

Two types of hydrotreatment process allowing the treatment of heavy loads such as atmospheric residues (RA) or under vacuum (RSV) exist: fixed bed processes and bubbling bed processes. Zong et al. (Recent Patents on Chemical Engineering, 2009, 2, 22-36) summarize the various known processes in the treatment of heavy petroleum charges.

The technology of fixed bed processes is industrially the most widespread because of its technical maturity, lower cost and stable and reliable performance. In such processes, the charge circulates through several fixed bed reactors arranged in series, the first reactor or reactors being used to mainly carry out the hydrodemetallization of the charge therein (so-called HDM step) as well as part of the hydrodesulfurization, the last reactor or reactors being used to carry out deep refining of the feedstock therein and in particular hydrodesulfurization (so-called HDS step) The refined effluents are withdrawn from the last hydrotreatment reactor.

Fixed bed processes lead to high refining performance (production of 370 ° C + cuts with less than 0.5% by weight of sulfur and containing less than 20 ppm of metals) from feed containing up to 5% by weight of sulfur and up to 300 ppm of metals, especially nickel and vanadium). The different effluents thus obtained can serve as bases for the production of good quality heavy fuel oils, diesel and petrol, or feedstocks for other units such as catalytic cracking.

Generally to compensate for this deactivation of the catalyst, the reactor temperature is increased, which promotes the formation of coke and accelerates the intragranular clogging processes (clogging of the internal porosity of the catalyst) and extragranular (clogging of the catalytic bed).

Another problem posed by the catalytic hydrotreatment in a fixed bed of these fillers is the clogging of the catalytic beds, in particular at the level of their upper part, and more particularly for the first catalytic bed in contact with the load, by the deposition of asphaltene compounds and sediment contained in the load. This clogging contributes to the acceleration of the deactivation phenomenon and generates an increase in the pressure drop in the reactor requiring sooner or later a shutdown of the unit for replacement of the catalyst.

We have sought to resolve these drawbacks of arrangements in fixed beds in various ways, in particular by using guard beds arranged upstream of the main reactors. The main task of guard beds is to protect the catalysts of the main downstream hydrotreatment reactors by carrying out part of the demetallation and by filtering the particles contained in the feed which can lead to clogging. Guard beds are generally integrated into the HDM section in a hydrotreatment process for heavy loads generally including a first section of HDM, then a second section of HDT. Although guard beds are generally used to carry out a first hydrodemetallization and filtering, other hydrotreatment reactions (HDS, HDN ...) will inevitably take place in these reactors thanks to the presence of hydrogen and a catalyst.

We have therefore thought of installing one or more reactors in a moving bed at the head of the HDM stage (US 3,910,834 or GB 2,124,252). These mobile beds can work co-current (HYCON process from SHELL for example) or counter-current (OCR process from Chevron Lummus Global and HYVAHL-MTM process from the applicant for example).

We have also thought of adding a fixed bed guard reactor in front of the HDM reactors (US 4118310 and US 3968026). Most often this guard reactor can be short-circuited by the use in particular of an isolation valve. This provides temporary protection of the main reactors against clogging.

Likewise, there has been described in the documents FR 2681871 and US 5417846, a system making it possible to associate the high performances of the fixed bed with a high operating factor for the treatment of loads with high metal contents which consists of a process of hydrotreatment in at least two stages of a heavy fraction of hydrocarbons containing asphaltenes, sulfur impurities and metallic impurities in which during the first step called HDM, the charge of hydrocarbons and hydrogen is passed over an HDM catalyst, then the effluent from the first stage is passed over an HDT catalyst. The HDM section includes one or more HDM zones in fixed beds preceded by at least two HDM guard zones, also called "swappable reactors", also in fixed beds, arranged in series to be used in a way cyclic consisting of the successive repetition of steps b) and c) defined below:

a) a step, in which the guard zones are used together for a duration at most equal to the deactivation and / or clogging time of one of them,

b) a step, during which the deactivated and / or clogged guard zone is short-circuited and the catalyst which it contains is regenerated and / or replaced by fresh catalyst and during which the other guard zone (s) are used,

c) a step, during which the guard zones are used all together, the guard zone whose catalyst was regenerated during the previous step being reconnected and said step being continued for a duration at most equal to the deactivation time and / or clogging of one of the guard zones.

Also known from document US 8632673 is a process for the treatment of heavy petroleum charges involving a system which comprises a hydrodemetallization section and a hydrodesulfurization section downstream, both of which are constructed in a switchable manner so as to optimize the durations of operating cycles of the treatment process.

An object of the present invention is to provide an alternative method for treating heavy loads of hydrocarbons which is optimized not only from the point of view of its operating time but also in terms of operating expenses.

Summary of the invention

The present invention therefore relates to a process for treating a hydrocarbon feedstock containing asphaltenes, sediments, sulfur, nitrogenous and metallic impurities in which the feedstock passes through a filtration section and then a catalytic section located downstream of the filtration section, the filtration section including at least two fixed bed filtration units arranged in series, operating in a switchable manner and the catalytic section including at least one fixed bed catalytic reactor, it being understood that the total volume of the fixed beds of filtration is between 1% and 50% of the total volume of catalyst in the catalytic section, the process comprising a plurality of cycles, each cycle comprising at least the following steps:

A step a) during which the filtration units and the catalytic reactors are used all together in series for a duration at most equal to the clogging time of the filtration unit most upstream relative to the direction of flow of the charge ;

• a step b) during which the filtration unit is short-circuited most upstream of the filtration section, the clogged filtration bed is removed from said unit while the other filtration unit (s) are used in such a way the charge is introduced into the filtration unit located immediately after the short-circuited unit;

• a step c) during which the clogged filtration bed is replaced with at least partially deactivated catalyst from the catalytic reactor of said catalytic section which has been optionally stored beforehand;

• a step d) during which the short-circuited filtration unit is reconnected so that it is located furthest downstream from the filtration section;

• a step e) during which the catalytic reactor is stopped and at least part of the partially deactivated catalyst is withdrawn from the catalytic bed;

• a step f) during which the stopped catalytic reactor is filled with fresh catalyst;

• a step g) during which the catalytic reactor containing fresh catalyst is reconnected.

The method according to the invention thus implements a filtration section using at least two fixed bed filtration units which are arranged in series and operated in a permutable manner, that is to say that the most upstream (relative to the direction of flow of the load) loaded with impurities is short-circuited by the filtration section the time for unloading and replacing the dirty bed while the filtration unit located just downstream continues to be used . The short-circuited unit whose filtration bed has been recharged is then reconnected so as to be located furthest downstream from the filtration section. The method according to the invention is also characterized by the fact that, during normal operation of the system, the dirty filtration bed is replaced by partially or totally deactivated (non regenerated) catalyst from the catalytic section. Thus the partially or totally deactivated catalyst is advantageously reused as a filtering medium in order to capture the clogging impurities contained in the heavy load of hydrocarbons, hence a non-negligible gain in terms of operating costs. Furthermore, when the catalyst recycled to the filtration section still exhibits catalytic activity, the latter can be advantageously used in the filtration section, in the presence of hydrogen, to catalytically pretreat the feed before the catalytic section proper.

In the context of the invention, the most upstream filtration unit in the overall direction of flow of the charge is gradually loaded with metals, coke, sediments and other various impurities and is generally disconnected when the pressure drop reaches a threshold value. For example, the filtration unit is stopped when the pressure drop measured in said unit is between 0.5 and 1 MPa, preferably between 0.5 and 0.8 MPa.

According to a preferred embodiment, the catalytic section downstream of the filtration section comprises at least two catalytic reactors arranged in series and operating in a permutable manner. The process is characterized by the fact that:

• in step e), the catalytic reactor is stopped and short-circuited most upstream relative to the direction of circulation of the charge, at least part of the partially deactivated catalyst is withdrawn from the catalytic bed while the other catalytic reactors are used so that the charge from the filtration section is introduced into the catalytic reactor located immediately after the short-circuited catalytic reactor and • in step g), the catalytic reactor containing fresh catalyst is reconnected so that it is located furthest downstream from the catalytic section.

The serial combination of these two interchangeable sections provides a continuous load treatment system which does not require shutdown of said system in order to replace fouled filtration beds and deactivated catalytic beds.

According to one embodiment, steps b) and e) are carried out concomitantly. For example, part of the partially deactivated catalyst recovered according to step e) is then directly transferred according to step c) into the short-circuited filtration unit.

According to one embodiment, at least part of the at least partially deactivated catalyst recovered in step e) is stored with a view to step c) of a following operating cycle.

According to the invention, per cycle, steps b), c) and d) can be repeated at a higher frequency than that of steps e), f) and g).

According to the invention, the total volume of the filtration beds of the filtration section is preferably between 1 and 20% of the total volume of catalyst of the catalytic section, more preferably between 2 and 15% of the total volume of catalyst of the catalytic section.

For easier management of the filtration section, each of the fixed filtration beds has substantially the same volume.

According to the invention, the fixed filtration beds comprise a mixture including filtration elements and partially deactivated catalyst.

The filtration section is generally operated with an hourly volume speed of between 0.1 and 0.5 h ¹ . In a preferred embodiment, the filtration section is operated in the presence of hydrogen in order to pretreat the charge in the filtration unit.

According to the invention, the catalytic section comprises at least one hydrodemetallization reactor. And preferably, the catalytic section further comprises at least one hydrodesulfurization reactor disposed downstream of the hydrodemetallization reactor.

Detailed description of the invention

The other characteristics and advantages of the invention will appear on reading the description which follows, given by way of illustration only and without limitation, with reference to the appended figures and described below:

• Figure 1 shows a first diagram of the method according to the invention;

FIG. 2 is another diagram of the process according to the invention in which the catalytic section comprises at least two permutable reactors;

• Figure 3 is a block diagram of a process not in accordance with the invention;

• Figure 4 shows the evolution of the pressure drop measured for the permutable catalytic reactors in the process of Figure 3;

• Figure 5 shows the evolution of the pressure drop measured for the permutable reactors in the process according to the invention;

• Figure 6 shows the evolution of the pressure drop measured for the permutable filtration units F1, F2 in the method according to the invention.

The treatment process according to the invention is particularly suitable for treating heavy loads of hydrocarbons chosen from atmospheric residues, vacuum residues from direct distillation, crude oils, headless crude oils, deasphalted oils, residues from conversion processes such as, for example, those from coking, hydroconversion in a fixed bed, in a bubbling bed, or even in a moving bed, heavy oils of any origin and in particular from bituminous sands or shales, taken alone or in mixture. These fillers can advantageously be used as such or further diluted with a hydrocarbon fraction or a mixture of hydrocarbon fractions which can be chosen from the products resulting from a catalytic cracking process in a fluid bed (FCC according to the initials of the Anglo-Saxon name of "Fluid Catalytic Cracking >>), a light cutting oil (LCO according to the initials of the Anglo-Saxon name of" Light Cycle Oil >>), a heavy cutting oil (HCO according to the initials of the Anglo-Saxon name of "Heavy Cycle Oil >>), a decanted oil (DO according to the initials of the Anglo-Saxon name of" Decanted Oil >>), an FCC residue, or which may come from distillation, the diesel fractions in particular those obtained by distillation under vacuum called according to the Anglo-Saxon terminology VGO ("Vacuum Gas Oil"). Heavy fillers can also advantageously include cuts from the coal liquefaction process, aromatic extracts, or any other hydrocarbon cuts or even non-petroleum fillers such as gaseous and / or liquid derivatives (containing little or no solids) thermal conversion (with or without catalyst and with or without hydrogen) of coal, biomass or industrial waste such as, for example, recycled polymers.

Said heavy loads generally have more than 1% by weight of molecules having a boiling point greater than 500 ° C., a nickel + vanadium metal content greater than 1 ppm by weight, or even greater than 20 ppm by weight, an asphaltenes content, precipitated in heptane, greater than 0.05% by weight, or even greater than 1% by weight.

FIG. 1 represents a diagram of the method according to a first embodiment. The process uses a filtration section A and a catalytic section B arranged downstream of the filtration section A. In the example of FIG. 1, the filtration section A, which plays the role of guard section, includes two filtration units 1 and 2 arranged in series and connected to each other by lines provided with valves V1 to V6. Each of the filtration units has a filtration bed F1 and F2 respectively. The catalytic section B, in the example of FIG. 1, comprises two reactors 3 and 4 with a fixed catalytic bed, arranged in series. For example, reactor 3 is a hydrodemetallization reactor containing a catalytic bed R1 and reactor 4 is a hydrodesulfurization reactor containing a catalytic R2.

According to the invention, the total volume of the filtration beds is between 1% and 50% of the total volume of catalyst in the catalytic section B. In a preferred embodiment, the volume of each of the filtration beds in a section filtration A is substantially equal.

It is of course possible to have more than two reactors for the catalytic section B.

The method according to the invention comprises, for the operation of the filtration section A, a repetition of a sequence including the following steps:

• a first stage during which the hydrocarbon charge passes successively through all the filtration units;

• a second stage during which the load successively passes through all the filtration units except the most upstream filtration unit which is short-circuited to replace the filtration bed;

• a third step during which the short-circuited filtration unit whose filtration bed has been replaced is reconnected to the filtration section so as to be in the most downstream position relative to the direction of circulation of load;

• a fourth stage during which the charge again passes successively through all the filtration units (equivalent to the first stage).

During the first step, the charge is introduced, through line 5 and line 6 which includes a valve V1 open towards line 8, into the filtration unit 1 containing a fixed filtration bed F1. During this period the valves V2, V3 and V5 are closed. The effluent from the filtration unit 1 is sent through the pipe 10, the pipe 11 comprising an open valve V4 and the pipe 9 in the filtration unit 2 containing a fixed filtration bed F2. The effluent from the second filtration unit 2 is sent via lines 14 and 15 comprising an open valve V6 and line 17 to the catalytic section B of the process. During this step, the filtration bed F1 of the filtration unit 1 (the most upstream with respect to the overall direction of circulation of the hydrocarbon charge) clogs faster because of the asphaltenes and other impurities contained in the charge, which results in an increase in pressure drop in the filtration bed.

When the pressure drop reaches a threshold value defined by the operator, for example when it is between 0.5 and 1 MPa, it follows the implementation of a second step in which the valves V1, V3, V4 and V5 are closed and the hydrocarbon charge is introduced via line 5 and line 7 comprising a valve V2 open towards line 9 in the second filtration unit 2. Thus the filtration unit 1 most upstream is short-circuited of the filtration section A. During this period the hydrocarbon charge is sent to the filtration unit located just downstream of the short-circuited unit, that is to say in the example of Figure 1 in the filtration unit 2, and the effluent from the second filtration unit 2 is sent through the lines 14 and 15 having an open valve V6 and the line 17 to the catalytic section B.

A third step is then carried out which consists in removing the filter bed F1 loaded with clogging elements from the short-circuited filtration unit and replacing it with a new filtration bed, the details of which are given below.

Once the filtration bed has been replaced in the short-circuited filtration unit, a fourth step is carried out on the filtration section A which consists in reconnecting this filtration unit so that it is located furthest downstream from the section filtration A with respect to the direction of flow of the charge. Then the load is circulated in all of the filtration units of the filtration section A. In the case of FIG. 1, the filtration unit 1 whose bed has been replaced therefore sees the load after the latter has passed through the filtration unit 2. During this step the valves V1, V4 and V6 are closed and the valves V2, V5 and V3 are open. The charge is introduced via line 5 and lines 7 and 9 into the filtration unit 2. The effluent withdrawn from the filtration unit 2 is sent through line 14, line 13 comprising the valve V5 open and the line 8 in the filtration unit 1. The effluent from the filtration unit 1 is sent via lines 10 and 12 comprising an open valve V3 and line 17 to the catalytic section B.

The cycle then begins again with always a short circuit of the filtration unit located furthest upstream with respect to the direction of flow of the hydrocarbon charge. The operations on the valves of the filtration section allowing the operation of the permutable filtration units are reported in Table 1.

Sequences for the section Intervention V1 V2 V3 V4 V5 V6 filtration 1 Unit 1 + Unit 2 - 0 * p ** F 0 F 0 2 Unit 2 works alone Short circuiting of unit 1 and bed replacement filtration F 0 F F F 0 3 Reconnecting unit 1 in downstream position F 0 0 F 0 F 4 = 1 Unit 2 + Unit 1 - F 0 0 F 0 F 2 Unit 1 works alone Unit 2 short-circuiting and replacement of the bed filtration 0 F 0 F F F

* Ο = open, ** F = closed

Table 1: Operations on the valves in filtration section A

The method according to the invention further comprises a step which consists in treating the effluent from the filtration section A in a catalytic section B. As indicated in FIG. 1, the catalytic section comprises two reactors 3 and 4 arranged in series . The effluent extracted from reactor 3 is sent via line 30 to reactor 4 from which a refined effluent is drawn off via line 31. In the context of the invention, the catalytic section B can of course comprise more than two catalytic reactors in series.

During the operation of the process, the catalysts of the reactors of the catalytic section B deactivate, progressively decreasing the conversion yield. According to the invention, for example when the pressure drop in the filtration unit located furthest upstream with respect to the direction of circulation of the hydrocarbon charge is reached or because the conversion efficiency of the catalytic section is too low, the installation is then stopped, which allows the following operations:

i. withdrawal of the clogged filtration bed and its replacement;

ii. drawing off a part of the deactivated or partially deactivated catalyst from the catalytic section and replacing it with fresh or regenerated catalyst.

According to the invention, the replacement of the clogged filtration bed of the short-circuited filtration unit is carried out with deactivated catalyst (not regenerated) which comes from one of the reactors of the catalytic section B.

The replacement of the filtration bed of the short-circuited unit can be done concomitantly when the catalytic reactor is stopped. According to this first mode of operation, only part of the volume of partially deactivated catalyst is withdrawn from the catalytic reactor which corresponds substantially to the volume of the filtration bed to be replaced and which is directly returned to the short-circuited filtration unit.

Alternatively, a volume of partially deactivated catalyst is drawn off which is greater than that of the volume of the filtration bed to be replaced or the entire volume of partially deactivated catalyst and the necessary volume is recycled directly into the short-circuited filtration unit while the complementary part of the partially deactivated catalyst that is not recycled is stored for later use. When a deactivated catalyst storage is available, it is then possible to subsequently short-circuit and replace the filtration bed of the filtration unit in a time-shifted manner relative to the time of l '' catalytic reactor shutdown.

According to the invention, when the volume of at least partially deactivated catalyst stored is sufficient, for one cycle, the replacement of the filtration bed can be done at a higher frequency than that of the replacement of the catalytic bed of the catalytic section.

FIG. 2 shows another diagram of the process according to the invention which differs from that of FIG. 1 by the fact that the catalytic section B comprises at least two catalytic reactors arranged in series and capable of operating in a manner permutable to the image of the filtration section. It should be noted that the catalytic section B can comprise downstream of the permutable catalytic reactors one or more reactors in series in a fixed catalytic bed.

The operating principle of the filtration section A is also similar to that described with reference to FIG. 1.

As shown in FIG. 2, the catalytic section B comprises two catalytic reactors R1A and R1B arranged in series and connected to each other by lines provided with valves V7 to V12. Furthermore, the catalytic beds Ra and Rb comprise the same type of catalyst, that is to say of identical formulation and carrying out the same catalytic reaction. For example, the catalytic beds Ra and Rb of the reactors R1A and R1B which are placed immediately downstream of the filtration section contain hydrodemetallization catalysts. It is of course possible to combine other catalytic reactors upstream or downstream of the permutable catalytic reactors R1A and R1B. The switchable catalytic section can also include more than two reactors in series.

In this embodiment, the permutable catalytic reactors R1A and R1B are operated cyclically by repeating the following steps:

• a first step during which the effluent from the filtration section successively passes through all the catalytic reactors;

• a second step during which the most upstream catalytic reactor is stopped and short-circuited to replace the deactivated catalytic bed while the charge successively passes through the other catalytic reactor (s) of the permutable section;

• a third step during which the short-circuited catalytic reactor whose bed has been replaced is reconnected to the catalytic section so as to be in the most downstream position relative to the direction of flow of the charge;

• a fourth stage during which the effluent from the filtration section again passes successively through all the catalytic reactors (equivalent to the first stage).

The operating principle of the catalytic section is described with reference to FIG. 2 in which said catalytic section B comprises two catalytic reactors R1A and R1B. In accordance with the first step, the effluent from the filtration section A is introduced via line 17 and line 18 comprising a valve V8 open towards line 20 in the catalytic reactor R1A containing a fixed catalytic bed Ra. During this period the valves V7, V9 and V11 are closed. The effluent from the catalytic reactor R1A is sent via line 21, line 23 comprising an open valve V10 and line 24 in the catalytic reactor R1B containing a fixed catalytic bed Rb. The effluent from the catalytic reactor R1B is discharged from the catalytic section which can be exchanged via the lines 25 and 27 comprising an open valve V12 and the line 28. During this stage, the catalytic bed Ra of the catalytic reactor R1A, the most upstream of the permeable catalytic section deactivates faster, in particular due to the deposition of metals and coke on the surface of the catalyst.

A second step is carried out on the permutable catalytic section which consists in stopping and short-circuiting the catalytic reactor most upstream relative to the overall direction of circulation of the hydrocarbon charge and in circulating the effluent from the section filtration A through only the non-disconnected catalytic reactor (here the R1 B catalytic reactor) or through the other catalytic reactors located downstream of the short-circuited catalytic reactor (when the permutable catalytic section includes more than two reactors in series). To this end, the valves V8, V9, V10 and V11 are closed and the hydrocarbon charge is introduced via line 19 comprising a valve V7 open towards line 24 in the catalytic reactor R1 B.

There is also a third step which consists in evacuating from the catalytic reactor R1A stopped and short-circuited at least a part of the catalytic bed Ra at least partially deactivated and replacing it with fresh or regenerated catalyst.

After replacement with fresh or regenerated catalyst, a fourth step is carried out on the permutable catalytic section which consists in reconnecting the short-circuited reactor R1A so that it is located furthest downstream from the permeable catalytic section with respect to the direction of circulation of the charge and then the charge is circulated through all of the catalytic reactors of the catalytic section B. In the case of FIG. 2, the effluent from the filtration section A is introduced through lines 19 and 24 in the catalytic reactor R1 B. The effluent from the catalytic reactor R1B then feeds the catalytic reactor R1A whose bed has been replaced. During this step the valves V8, V12 and V10 are closed and the valves V7, V11 and V9 are open. The effluent from the catalytic reactor R1A is withdrawn from the catalytic section B via lines 21, 22 and 28.

The operating cycle of the catalytic section then starts anew again, always with a short circuit of the catalytic reactor located furthest upstream with respect to the direction of flow of the hydrocarbon charge.

According to the invention, the filtration bed of the short-circuited filtration unit is replaced by at least partially deactivated catalyst from one of the reactors of the catalytic section B which has been short-circuited.

According to a first mode of operation of the method according to the invention, during normal operation of the method, the short-circuiting and replacement of the filtration bed of the filtration unit most upstream relative to the overall direction of flow of the charge (stages b) and c)) is carried out concomitantly with stopping, short-circuiting and replacing the catalytic bed of the catalytic reactor most upstream relative to the overall direction of circulation of the charge of the catalytic section ( steps e) and f)). According to this first mode of operation, for example only part of the volume of catalyst at least partially deactivated from the short-circuited catalytic reactor is withdrawn, which corresponds substantially to the volume of the filtration bed to be replaced. The at least partially deactivated catalyst is directly sent to the short-circuited filtration unit. Alternatively, a volume of partially deactivated catalyst is drawn off which is greater than that of the volume of the filtration bed to be replaced or the entire volume of partially deactivated catalyst and the necessary volume is recycled directly into the short-circuited filtration unit while the complementary part of the partially deactivated catalyst that is not recycled is stored for later use in the filtration section.

According to a second mode of operation of the method according to the invention, the short-circuiting and replacement of the filtration bed of the filtration unit most upstream of the filtration section (steps b) and c)) is done by offset in time with respect to shutdown, short-circuiting and replacement of the catalytic bed of the reactor furthest upstream from the catalytic section (steps e) and f)). In this second operating mode, it is possible, for example, to withdraw and store a volume of partially deactivated catalyst which is substantially equal to the volume of the filtration bed to be replaced later. Alternatively, a volume of partially deactivated catalyst is drawn off which is greater than that of the volume of the filtration bed to be replaced subsequently or all of the volume of partially deactivated catalyst and this volume is stored for subsequent replacement of a filtration bed. .

A particular mode of operation of the method according to FIG. 2 is detailed below. The main steps are grouped in Table 2 below and with reference to the elements in Figure 2.

Section of filtration Intervention in the filtration section Section catalytic permutable Intervention at the level of the Catalytic Section Process step according to the invention Start-up 1 +2 R1A + R1B 2 alone Stop and short circuit 1 and replacement with deactivated catalyst already available R1A + R1B 2 Reconnection of 1 downstream R1A + R1B 2 + 1 R1A + R1B 1 single Short circuit of 2 R1B alone R1A stop and short-circuit, drawdown and storage of partially deactivated catalyst 1 single Replacement of the filtration bed of 2 with deactivated catalyst already available and reconnection of 2 downstream R1B alone Replacement of the R1A catalytic bed with fresh or regenerated catalyst then reconnection of the R1A reactor downstream Cycle 1 1 +2 R1B + R1A at) 2 alone Stop and short circuit 1 and replacement with deactivated catalyst of the previously stored reactor R1A R1B + R1A b) and c) 2 alone Reconnection of 1 downstream R1B + R1A d) 2 + 1 R1B + R1A 2 + 1 R1A alone Stop and short circuit R1 B, withdrawal and storage of partially deactivated catalyst from R1B e) 2 + 1 R1A alone Replacement of the R1B catalytic bed with fresh or regenerated catalyst then reconnection of R1B downstream f) and g) Cycle 2 2 + 1 R1A + R1B at)

Table 2: Example of cyclic operating mode of the method according to the invention

The process begins with a transient so-called start-up phase which will make it possible to generate an at least partially deactivated volume of catalyst which will be sufficient to be reused during the following cycles in normal process operation.

As indicated in the table, the process starts by operating the filtration units 1 and 2 and the catalytic reactors R1A and R1B all together until the time of clogging (for example reaching a limit pressure drop) of the filtration bed. the most upstream filtration unit 1. The most upstream unit 1 is then short-circuited while the hydrocarbon charge is treated in the filtration unit 2 downstream of the short-circuited unit 1 then in the permutable catalytic section which continues to operate the R1A and R1 B catalytic reactors. The filtration bed is also replaced with either partially deactivated catalyst available, for example from an operating cycle prior to start-up, or with fresh filter media. After replacing the filtration bed of the short-circuited unit 1, the latter is reconnected to the filtration section so as to be located furthest downstream from the filtration section with respect to the direction of flow of the charge, in the case present downstream of unit 2.

Again all the filtration units and all the catalytic reactors are implemented together for a time corresponding to the clogging of the filtration bed of unit 2. We then proceed to the short-circuiting of unit 2 and of the catalytic reactor R1A the beds of which are replaced respectively by either partially deactivated catalyst available or with fresh filter medium and fresh catalyst. As for the at least partially deactivated catalyst recovered from the reactor R1A, it is stored for use in the following cycle.

It should be noted that during the short-circuiting phase of unit 2 and of reactor R1A, the filtration unit 1 and the catalytic reactor R1B continue to process the charge.

Once the filtration and catalytic beds have been replaced, the filtration unit 2 and the reactor R1A are then reconnected respectively downstream of the filtration unit 1 and of the catalytic reactor 2 so that the process according to the invention can start. by successively repeating steps a) to g), namely:

A step a) during which the filtration units 1 and 2 and the catalytic reactors R1B and R1A are used all together in series for a period at most equal to the clogging time of the filtration unit 1 most upstream relative in the direction of flow of the load;

• a step b) during which the filtration unit 1 is short-circuited most upstream of the filtration section, the clogged filtration bed is withdrawn from said filtration unit 1 while the charge is introduced into the unit filtration 2 which is located immediately after the shorted unit 1;

• a step c) during which the clogged filtration bed of unit 1 is replaced by at least partially deactivated catalyst which has been stored and which comes from the catalytic reactor R1A or R1B (previously short-circuited);

• a step d) during which the short-circuited filtration unit 1 is reconnected so that it is located furthest downstream from the filtration section, in this case downstream from the filtration unit 2;

• a step e) during which the R1B catalytic reactor is short-circuited most upstream relative to the direction of flow of the charge, at least part of the partially deactivated catalyst is withdrawn from the catalytic bed while the R1A catalytic reactor is used only;

• a step f) during which the short-circuited catalytic reactor R1B is filled with fresh catalyst;

· A step g) during which the R1B catalytic reactor containing fresh catalyst is reconnected so that it is located furthest downstream from the catalytic section, in this case downstream from the R1A reactor.

After step g), a sequence of steps a) to g) is restarted.

According to the invention, the process can be operated in such a way that the volume of at least partially deactivated catalyst withdrawn from a single reactor can be used to replace the volume of the two filtration units. In this embodiment and when the volume of at least partially deactivated catalyst stored is sufficient, per cycle, the replacement of the filtration bed can be done at a higher frequency than that of the replacement of the catalytic bed of the catalytic section.

Table 3, which does not include the start-up phase already mentioned above, gives an example of this type of operation and in which, per cycle, the frequency of replacement of the filtration bed is twice that of replacement of the catalytic bed. of the catalytic section.

Filtration section Intervention in the filtration section Section catalytic Intervention at the level of the Catalytic Section Process step according to the invention Cycle 1 1 +2 R1B + R1A at) 2 alone Short-circuiting of 1 and replacement with deactivated catalyst of R1A previously stored R1B + R1A b) and c) 2 alone Reconnection of 1 downstream R1B + R1A d) 2 + 1 R1B + R1A at) 1 single Short-circuiting of 2 and replacement with deactivated catalyst of R1A previously stored R1B + R1A b) and c) 1 single Reconnection of 2 downstream R1B + R1A d) 1 +2 R1B + R1A at) 1 +2 R1A alone Stop and short circuit R1 B, withdrawal and storage of partially deactivated catalyst from R1B e) 1 +2 R1A alone Replacement of the R1B catalytic bed with fresh or regenerated catalyst then reconnection of R1B downstream f) and g) Cycle 2 1 +2 R1A + R1B

Table 3: Example of operating mode of the method according to the invention.

Those skilled in the art can easily modify the frequency of replacement of the filtration beds as a function of the volume of the catalytic bed of the permeable section.

According to an alternative, the process can be operated so that the stages of short-circuiting the filtration unit and the reactor most upstream relative to the direction of circulation of the charge take place at the same time, as described in the table. 4 below which does not resume the start-up phase already mentioned above:

Filtration section Intervention in the filtration section Section catalytic Intervention at the level of the Catalytic Section Process step according to the invention Cycle 1 1 +2 R1B + R1A at) 2 alone Stop and short-circuit 1 and replace with deactivated catalyst of R1A previously stored R1A alone Stop and short circuit R1 B, withdrawal and storage of partially deactivated catalyst from R1B b), c), e) 2 alone R1A alone 2 alone Reconnection of 1 downstream R1A alone Replacement of the R1B catalytic bed with fresh or regenerated catalyst then reconnection of R1B downstream d), f) and g) Cycle 2 2 + 1 R1A + R1B at)

Table 4: Example of operating mode of the method according to the invention

Note that in this embodiment, the reconnections of the short-circuited filtration unit and of the short-circuited catalytic reactor can be carried out concomitantly or deferred.

According to the invention, the filtration bed of the filtration units can further comprise filtration elements. The filtration elements can be of polygonal, cylindrical or circular shape, for example in the shape of a cartwheel, as described in document US Pat. No. 8,062,521.

Example 1 (not in accordance with the invention):

The charge is atmospheric residue (RA) of Middle East origin (Arabian Medium). This charge is characterized by a high viscosity (82.5 cSt at 100 ° C), a density of 985 kg / rrP, high levels of Conradson carbon (14% by weight) and asphaltenes (6% by weight) and a high quantity of nickel (26 ppm by weight), vanadium (80 ppm by weight) and sulfur (4% by weight).

The load treatment process implements two interchangeable reactors (R1A and R1B) connected followed by three reactors in fixed beds R2, R3 and R4 as shown in Figure 3. The functioning of the interchangeable reactor system is described in the document WO 2012/095566. The two interchangeable reactors R1A and R1B are loaded with a hydrodemetallization catalyst of the CoMoNi / alumina type. The reactors R2, R3, R4 are loaded with hydrotreatment catalysts of the CoMoNi / Alumina type. An industrial cycle is defined as the repetition of at least one sequence integrating steps from a) to d) of Table 5 below. The end of the cycle (complete shutdown of the unit) can occur at any stage of this sequence.

Cycle Stage Intervention V1 V2 V3 V4 V5 V6 at R1A + R1B - 0 * 0 p ** F F 0 b R1B R1A F F 0 F F 0 vs R1B + R1A - F F 0 0 0 F d R1A R1B 0 F F F 0 F at R1A + R1B - 0 0 F F F 0

* O = open, ** F = closed

Table 5: Operations on the valves around the switchable reactors in Figure 3.

It is considered that the clogging of the filter is reached when the pressure drop in one of the filtration units F1, F2 reaches 0.7 MPa (7bars). It is also considered that the catalyst in a switchable reactor of the catalytic section is deactivated when the average temperature in the switchable reactor reaches 415 ° C. and / or when the temperature difference on a catalytic bed becomes radially greater than 5 ° C.

The process is carried out under a partial pressure of hydrogen of 15 MPa at the inlet of the catalytic section, an average temperature on at least one hydrotreatment reactor that cannot be changed at the start of the cycle of 360 ° C. and at the end of the cycle of 415 ° C approximately, and an overall WH of 0.27 h ¹ (the WH of a swappable reactor being in this case 1.4 h ¹ ).

This catalytic system allows about 86% hydrodesulfurization.

In FIG. 4, on the abscissa is shown the operating time (in days) of the swappable reactors and on the ordinate is the pressure drop measured for the swappable reactors. Thus, according to FIG. 4, the curve of the reactor R1A shows at the start of the cycle an increase in the pressure drop to its maximum tolerable value (ΔΡ = 0.7 MPa or 7 bars) from which it is necessary to proceed with the replacement of the catalyst. The operating time of the Ra reactor is therefore 210 days before its shutdown. When the R1A reactor was put back into service downstream from the R1B reactor, the pressure drop in the R1B reactor reached approximately 0.3 MPa (3 bars). During the next phase where the charge passes through the R1B reactor and then the R1A reactor containing a new catalyst, the pressure drop of the R1B reactor increases to the maximum tolerable value, which is reached after 320 days of operation. In this example, after 320 days, the entire unit is stopped to replace the deactivated catalysts of the fixed-bed reactors R2, R3 and R4 and the catalytic bed of the permeable reactor R1B is also replaced. The catalyst of the bed of reactor R1A is not replaced insofar as the catalytic activity is sufficient and that the clogging is not prohibitive for the operation of the process. Indeed, it can be noted that when the unit stops, the pressure drop (ΔΡ) in the R1A reactor is approximately 0.18 MPa (1.8 bar). As indicated in FIG. 4, the operating time of the reactors R1A and R1B is 260 days and 290 days respectively for the second cycle.

In total, there is a cycle time of 320 days for the first cycle and 290 days for the second cycle (excluding the stop period between the two cycles).

Example 2 (according to the invention)

The process for treating the same charge as in Example 1 uses the same catalysts and under the same operating conditions as in Example 1. The process according to Example 2 uses a filtration section A comprising two permutable filters F1 and F2 placed upstream of the catalytic section which, as shown in FIG. 3, comprises the permutable reactors R1A and R1B and three catalytic reactors R2, R3 and R4. The cumulative volume of each filter (F1 or F2) is equal to 50% of the volume of each swappable reactor (R1A or R1B). The hydrodesulfurization rate is maintained at 88%.

As shown in FIG. 5, the lifetime for the first swappable reactor R1A is extended to 260 days and this end of life is due to catalytic deactivation and not to clogging since the pressure drop of R1A after 260 days does not reach only 0.41 MPa (4.1 bar). The deactivation of the catalyst leads to a shutdown of the R1A reactor for unloading and recharging with fresh catalyst. The catalyst present in the R1A reactor is used optimally and its unloading is facilitated since the bed is less clogged as evidenced by the lower pressure drop. The catalyst discharged from the reactor R1A is stored for use as a filtering medium in one of the two filters F1, F2. With reference to FIG. 6, during the first cycle and after 190 days of operation, the filter F1 is discharged and then recharged with deactivated catalyst previously stored. During the shutdown of unit F1, the filter F2 operates on its own. After recharging, the filter F1 is reconnected downstream of the filter F2 and the filtration section is operated with the filters F2 and F1.

With reference to FIGS. 5 and 6, the reactor R1A is stopped at 260 days and the adequate quantity of catalyst is discharged and is used to fill the filter F2 which has clogged after 280 days. When the F2 filter stops, which takes place at 280 days, the F1 filter works alone. After recharging, the filter F2 is reconnected downstream of the filter F1 and the filtration section is operated with the filters F1 and F2.

As shown in Figures 5 and 6, the unit is stopped for 360 days for the replacement of the catalyst of a fixed bed reactor R2, R3 or R4 downstream of the switchable catalytic reactors R1 A, R1 B. The catalyst bed from reactor R1B is also discharged, even if the catalyst still exhibits catalytic activity. The stored catalyst from R1B is then used to recharge the F1 filter at 450 days (Figure 6), which takes advantage of the residual catalytic activity of the catalyst. Following the recharging of the filter F1, the latter is reconnected downstream of the filter F2 and the filtration section is then operated with the filters F2 and F1.

At 570 days, the filter F2 is stopped and recharged with stored catalyst while the filter F1 operates alone. The filter F2 is then reconnected downstream of the filter F1 after recharging with deactivated catalyst and the filtration section operates with filters F1 and F2.

The filter F1 is recharged after 680 days with the stored catalyst coming from the R1A which was stopped at 640 days with a view to discharging its catalyst bed.

Due to the longer life of the R1A and R1B reactors, the catalysts of the downstream reactors are also better protected from deactivation. It will be noted that the duration of the first cycle for the permutable catalytic section (R1A, R1B) is extended to reach 360 days. The duration of the second cycle is also improved to reach 348 days.

Claims (14)

1. Process for treating a hydrocarbon feedstock containing asphaltenes, sediments, sulfur, nitrogenous and metallic impurities in which the feedstock crosses a filtration section and then a catalytic section located downstream from the filtration section, the section filtration including at least two fixed bed filtration units (1, 2) arranged in series, operating in a switchable manner and the catalytic section including at least one fixed bed catalytic reactor (3, 4), it being understood that the total volume fixed filtration beds is between 1% and 50% of the total volume of catalyst in the catalytic section, the process comprising a plurality of cycles, each cycle comprising at least the following steps: • a step a) during which the filtration units (1, 2) and the catalytic reactors (3, 4) are used all together in series for a period at most equal to the clogging time of the filter unit most upstream with respect to the direction of flow of the load; • a step b) during which the filtration unit is stopped and short-circuited most upstream of the filtration section, the clogged filtration bed is withdrawn from said unit while the other filtration unit (s) are used so that the charge is introduced into the filtration unit located immediately after the short-circuited unit; • a step c) during which the clogged filtration bed is replaced by at least partially deactivated catalyst originating from the catalytic reactor of said catalytic section which has been optionally stored beforehand; • a step d) during which the short-circuited filtration unit is reconnected so that it is located furthest downstream from the filtration section; • a step e) during which the catalytic reactor is stopped and at least part of the partially deactivated catalyst is withdrawn from the catalytic bed • a step f) during which the stopped catalytic reactor is filled with fresh catalyst; • a step g) during which the catalytic reactor containing fresh catalyst is reconnected. 2. Method according to claim 1, in which the catalytic section comprises at least two catalytic reactors (R1 A, R1 B) arranged in series and operating in a permutable manner and in which: • in step e), the catalytic reactor is stopped and short-circuited most upstream relative to the direction of flow of the charge, at least part of the partially deactivated catalyst is withdrawn from the catalytic bed while the other catalytic reactors are used so that the charge from the filtration section is introduced into the catalytic reactor located immediately after the short-circuited catalytic reactor and • in step g), the catalytic reactor containing fresh catalyst is reconnected so that it is located furthest downstream from the catalytic section. 3. Method according to claim 2, in which steps b) and e) are carried out concomitantly. 4. Method according to claim 3, in which part of the partially deactivated catalyst recovered according to step e) is directly transferred according to step c) into the short-circuited filtration unit. 5. Method according to one of the preceding claims, in which part of the partially deactivated catalyst recovered in step e) is stored with a view to step c) of a following operating cycle. 6. Method according to one of the preceding claims, wherein per cycle, steps b), c) and d) are repeated at a higher frequency than that of steps e), f) and g). 7. Method according to one of the preceding claims, in which the total volume of the filtration beds in the filtration section is between 1 and 20% of the total volume of catalyst in the catalytic section. 8. Method according to one of the preceding claims, wherein each of the fixed filtration beds has substantially the same volume. 9. Method according to one of the preceding claims, in which the fixed filtration beds comprise a mixture including filtration elements and partially deactivated catalyst. 5 10. Method according to one of the preceding claims, wherein the filtration section is operated with an hourly volume speed between 0.1 and 0.5 h ¹ . 11. Method according to one of the preceding claims wherein the filtration section is operated in the presence of hydrogen. 12. Method according to one of the preceding claims, in which the catalytic section comprises at least one hydrodemetallization reactor. 13. The method of claim 12, wherein the catalytic section comprises Furthermore at least one hydrodesulfurization reactor arranged downstream of the hydrodemetallization reactor. 1/4