KR100221005B1 - Hydrotreating process for heavy hydrocarbon fraction - Google Patents

Abstract

The present invention relates to a process comprising at least two steps of treating heavy hydrocarbon fractions containing asphaltenes, sulfur impurities and metal impurities comprising a first step of metal hydride removal followed by a second step of sulfur hydride removal. will be. The metal hydride removing step comprises one or more metal hydride removal regions of the fixed bed, and fixed beds arranged in series for circulating use, including successive repetitions of steps (b) and (c) as defined below. At least two preliminary metal hydride removal regions (A) and (B) in the front are operated prior to the metal hydride removal region. The present invention includes the following steps (a) to (c):

(a) using all of the spare areas together for a period of time less than the time required for any one of the spare areas to be inactivated or clogged; (b) bypassing the inactivated and / or clogged preliminary zone and regenerating and / or replacing the catalyst contained therein with a new catalyst; And (c) reconnecting the preliminary zone where the catalyst has been regenerated in step (b) to use all of the preliminary zones together for a period of time less than the time required for any one of the preliminary zones to be deactivated and / or clogged. step.

The process of the present invention may also include a pretreatment hydrogenation viscosity reduction step and optionally a final asphalt removal step using a solvent.

Description

Hydrogenation of Heavy Hydrocarbon Fractions

1 is a schematic of a conventional process using a fixed bed of catalyst.

2 is a schematic of a conventional process using a fluidized bed of catalyst.

3 is a schematic diagram of a device in which a standby reactor is inserted to maintain a good performance of a fixed bed.

4 (a), 4 (b) and 5 show a simplified view of the method of the present invention.

The present invention relates to asphaltenes, sulfur, and atmospheric residues, vacuum residues, asphalted oils, pitches, asphalt mixed with aromatic distillates, coal hydrogenated additives and other sources, in particular thickening oils derived from asphaltous sand or shale oil. A method for purifying and converting heavy hydrocarbon fractions containing metal impurities such as The invention relates in particular to a process for the treatment of a liquid feedstock.

Feedstocks which can be treated by the present invention are 100 ppm by weight or more of metals (nickel and / or vanadium), 1 weight Or more sulfur and 2% or more asphaltenes.

The purpose of catalytic hydrogenation of these feedstocks is to purify them. In other words, it reduces the asphaltenes, metals, sulfur and other impurities in the feedstock and at the same time improves the hydrogen / carbon (H / C) ratio, thereby converting them into partially lighter fractions. The various products thus obtained can provide raw materials that can be used as feedstock for higher fuel, gas oil or other units such as gasoline or residue cracking.

The problem encountered in the catalytic hydrogenation of these feedstocks is that they need to be shut down for catalyst exchange as impurities are attached little by little on the catalyst in the form of metals and cokes, which rapidly deactivates and blocks the catalyst system. Is that there is.

The hydroprocessing method used for this type of feedstock thus provides the longest possible operating cycle without interrupting the unit's operation, providing a minimum operating cycle of one year, ie continuous operation of at least 11 months and a maximum of 1 month. It shall be designed to provide a period of downtime for the exchange of the entire contact system.

There are various treatment methods for this type of feedstock. These methods are conventionally performed in the following manner:

-Using a fixed bed of catalyst (e.g. HYVAHL-F method of Total, Elf and Institut Francais du Petrole) or

-Using one or more reactors capable of semi-continuous exchange of catalysts (eg Elf, Institut Francais du Petrole and Total's HYVAHL-M fluidized bed method).

The method of the present invention is an improvement of the method of using a fixed bed of catalyst. In this method (see FIG. 1), the feedstock conveyed via line 1 passes through a number of fixed bed reactors arranged in series. The first reactor or reactors 26 and / or 27 are mainly used for the hydrodemetallization of the feedstock (so-called HDM stage) and for some of the hydrodesulfurization stages, the final reactor or reactors 28 and And / or (29) is used for the advanced purification of the feedstock and in particular for the hydrodesulfurization step (so-called HDS step). The product formed is withdrawn from the final HDS reactor 29 via pipe 21.

This process generally involves a catalyst specific for each stage at a pressure of about 150 to 200 bar and about 370 to 420 Use under average operating conditions of temperature.

The ideal catalyst for the HDM step should be suitable for processing feedstock enriched with asphaltenes; It should also have a high metal-holding capacity and high demetallization capacity associated with good resistance to coking. In order to provide exactly the following properties required for the HDM step, catalysts on certain macroporous carriers (having a "sew" structure) have been developed (European Patent-B 113297 and European Patent-B 113284):

Demetallization rate at -HDM stage 80 to 90 More than;

-60 for the weight of the new catalyst Properties that provide longer operating cycles with more metal-bearing capacity;

-400 Very good resistance to coking at these temperatures (promotes longer cycles, but is often limited by increased pressure loss (loss of feedstock) and increased loss of activity due to coke formation, Allow heat conversion).

The ideal catalyst for the HDS stage should be one with a high hydrogenation capacity to enable high purification of the product: desulfurization, subsequent demetallization and reduction of asphaltene content. Applicants have developed such catalysts (European Patent-B-113297 and European Patent-B-113284), which catalysts are particularly suitable for treating feedstocks of the aforementioned types.

A disadvantage of this type of catalyst with high hydrogenation capacity is that it is rapidly inactivated in the presence of metal or coke. HDM catalysts suitable for operating at relatively high temperatures to perform most conversion and demetallization reactions can be used at relatively low temperatures to obtain high hydrogenation and limited coking, protected from metals and other impurities by the HDM catalysts. By mixing with a suitable HDS catalyst, the overall result is better than what can be achieved with a similar HDM / HDS arrangement using a temperature rise procedure that results in better caulking of the HDS catalyst than that achieved with a single contact system. Purification performance is achieved.

The fixed bed method is important in that excellent purification performance is obtained by good contact efficiency of the fixed bed. On the other hand, when the feedstock has a specific metal content (eg 100 to 150 ppm) or higher, even the best contact system has been found to be inadequate in performance, in particular the operating time of the method; Reactor (especially the first HDM reactor) is deactivated as the metal is rapidly charged; The temperature must be raised to compensate for the inactivation, thus promoting coke formation and increasing pressure loss. In addition, the first catalyst layer tends to be somewhat rapidly colored due to deposits contained in asphaltenes and feedstocks or due to operational problems.

Therefore, the unit should be suspended at least once every 3 to 6 months to replace the deactivated or colored first catalyst layer. This operation can take three weeks, thus reducing the operating efficiency of the unit.

Various methods have been tried to overcome the disadvantages of the pinned layer.

In one example, one or more reactors with fluidized bed 24-A were mounted on top of the HDM stage (see FIG. 2) (US Patent-A 3910834 or British Patent-B-2124252). The fluidized bed may operate in cocurrent (eg SHELL's HYCON method) or countercurrent (eg Applicant's HYVAHL-M method). The fixed bed reactor is thus protected by performing some demetallization steps and filtering the particles contained in the feedstock which can cause clogging. In addition, by semi-continuously exchanging catalyst in the fluidized bed reactor (s) (withdrawing spent catalyst through pipe 61 and supplying fresh catalyst through pipe 60), the unit is suspended every 3-6 months. Can be prevented.

The disadvantage of this fluidized bed process is that its performance and efficiency are inferior to what can be achieved using a fixed bed of the same scale, which can lead to abrasion of the flowing catalyst and cause blocking of the downstream fixed bed, in particular If there is an operational problem when using heavy feedstocks under the operating conditions that are dangerous for caulking, then catalyst agglomeration cannot be ignored. This phenomenon can impede the flow of the catalyst in the reactor or in the line for discharging the spent catalyst, resulting in the need to shut down the unit to clean the reactor and the discharge line.

In order to maintain the excellent performance of the fixed bed while maintaining acceptable operating efficiency, there is an example of inserting a fixed bed pre-reactor (space velocity VVH = 2 to 4) upstream of the HDM reactor (US Pat. Nos. A 4118310 and -A 3968026). ). The preliminary reactor 24 can typically be bypassed by the valve 31 (see also FIG. 3). The preliminary reactor temporarily protects the main reactor from clogging. This is bypassed when the preliminary reactor is blocked, but the main reactor 26 may subsequently be blocked, so the unit must be shut down. In addition, the preliminary reactor 24 is small in size and does not significantly demetalize the feedstock. Therefore, it is hard to prevent metal from adhering to the main HDM reactors when the metal is a rich (150 ppm or more) feedstock. As such, the deactivation of the reactor is facilitated and the unit has to be run very rapidly, the operating efficiency is still inadequate.

According to the present invention, an excellent method that can combine the high performance of the fixed bed and the high operating efficiency for processing a high metal content (100 to 1500 ppm, typically 150 to 1400 ppm, preferably 300 to 1350 ppm) feedstock It has been found that it is at least a two-stage hydrotreating process for heavy hydrocarbon fractions containing asphaltenes, sulfur impurities and metal impurities. At this time, the hydrocarbon feedstock and hydrogen are passed through at least one hydrodemetallization catalyst under the plasticizing demetallization conditions during the so-called hydrodesulfation metallization step, and then discharged from the first stage in a subsequent second step. The material passes through one or more hydrodesulfurization catalysts under hydrodesulfurization conditions. The process of the present invention further comprises that the hydrodemetallization step comprises at least one fixed bed hydrodemetallization zone, upstream of the zone in series for circulation, comprising successive repetitions of steps (b) and (c) below. Two or more fixed bed prehydrogenation metallization zones arranged, preceded and characterized by comprising the following steps (a) to (c):

(a) using all of the spare areas together for a period of time less than the time required for one of the spare areas to be inactivated or occluded;

(b) bypassing the inactivated and / or occluded preliminary zone and regenerating and / or replacing the catalyst contained therein with a new catalyst; And

(c) reconnecting the preliminary zone from which the catalyst has been regenerated in step (b) and using all of the preliminary zones together for a period of time which is less than the time required for one of the preliminary zones to be inactivated and / or occluded.

In one variant of the process of the invention, the preliminary zones are used together in step (c), with the preliminary zone regenerating the catalyst in step (b) the same as it was connected before bypassing it in step (b). Reconnect in the same way.

Another variant of the process of the invention, the preferred embodiment of the invention comprises the following steps (a) to (c):

(a) using all of the spare zones together for a period of time that is less than the time required for the inactive and / or occluded spare zone located upstream to the flow direction of the entire feedstock to be treated;

(b) directly injecting the feedstock into the preliminary zone located immediately after the preliminary zone located most upstream during step (a), bypassing the most upstream preliminary zone during step (a) and contained therein Regenerating and / or replacing the catalyst with a new catalyst; And

(c) reconnect the preliminary zone from which the catalyst has been regenerated in step (b) downstream of all the preliminary zones, and the preliminary position most upstream to the flow direction of the entire feedstock to be treated during step (b). Using all of the spare areas together for a period of time that is less than the time required for the area to become inactive or occluded.

In a preferred embodiment of the present invention, metals, coke, precipitates and various other impurities are gradually charged in the preliminary zone, which is most upstream in the flow direction of the entire feedstock. This uppermost reserve zone is immediately separated as needed, but usually when the catalyst contained therein is saturated with metals and various impurities.

The preferred method of the present invention utilizes a special treatment zone during operation, i.e. the spare zone can be exchanged without stopping the unit. A system operating under moderate pressure (10 to 50 bar, preferably 15 to 25 bar) can first drain the spent catalyst after subsequent operation on a separate pre-reactor, i.e. washing, stripping and cooling. To ensure that; It is then possible to carry out heating and sulfiding when fresh catalyst is supplied. Another pressurization / decompression technique, a tap-valve system according to a suitable technique, then allows the spare area to be exchanged without actually stopping the unit, ie without affecting the operating efficiency at all. Because all operations of washing, stripping, exhausting spent catalyst, reloading fresh catalyst, heating and sulfiding are carried out in separate preliminary reactors or zones.

The reactor of the hydrotreating unit generally operates under the following hourly space velocity (VVH):

A preferred feature of the present invention is that the preliminary zone or reactor is operated under a total VVH (rate / volume / hour) of about 0.1 to 2.0, typically about 0.2 to 1.0. This is in contrast to other methods using small scale preliminary reactors, specifically those described in US Pat. No. A-3968026. The VVH value of each preliminary reactor in operation is preferably about 0.5 to 4, usually about 1 to 2. The total VVH value of the preliminary reactors and the VVH value of each reactor are selected to obtain the maximum HDM while controlling the reaction temperature (limiting the heat generation).

In a preferred embodiment of the present invention, each reactor of the preliminary zone has a capacity approximately equal to each reactor of the hydrogenohydrometallization demetallization zone (s).

By using suitable HDM / HDS catalysts, preferably the catalysts developed by the present application (European Patent-B-113297 and B-113284), and the specific embodiments of the present invention described above, the following effects can be obtained. It turned out to be:

Due to the efficiency of the selected VVH and HDM catalysts, the HDM ratio of the feedstock discharged from the preliminary reactor is 50 To 50 Above (more specifically, 50 to 92 HDM); This performance is up to about 35 in a preliminary reactor in the prior art method. In contrast to the lack of HDM alone. In addition, the high metal-retaining capacity of the catalyst (60 weight of metal attached to the weight of the new catalyst) Above), the average frequency of pre-reactor exchange (depending on the metal content of the feedstock) is, for example, about 0.5 to about 0.8 months, about 100 to about feedstock having a metal content of about 1000 ppm by weight or more. For feedstock with a metal content of about 600 ppm by weight it is about 1 to 6 months, more specifically 3 to 4 months. The average frequency of exchange is the average time of the entire length of the operating cycle, which is used to replace the running topmost prereactor containing spent catalyst with the next preliminary reactor containing a catalyst that is not yet saturated with metal and various impurities. Time elapsed before separation.

In the case of the main HDM and HDS reactors, operation cycles generally last at least 11 months; This performance is improved by the method of the present invention by means of a preliminary reactor. HDM), and excellent protection from problems of blockage by sediment, coke and other impurities. At the end of at least 11 months of operation cycle, which is obtained even with a feedstock having a high or very high metal content (100 to 1500 ppm, preferably 150 to 1400 ppm), the unit is stopped for the exchange of all catalysts contained in the main reactor. You have to. Since such an operation can be easily performed within one month, it is believed that the method of the present invention can achieve an operating efficiency of 0.92 or more (that is, 11 months out of 12 months). The operating efficiency is considerably greater than the operating efficiency of the prior art method using a fixed bed and is at least equal to the operating efficiency of the method using one or more fluidized beds. Particularly in the case of hydrogenation of feedstocks with very high metal contents, for example at least 500 ppm, at least three, usually at least four, preliminary reactors are used in series, which suddenly affects the upstream preliminary reactor in operation. Protection against possible problems (eg, caulking due to operational problems, or, in some cases, blockage by salts or sediments carried with the feedstock) can be ensured to maintain high operating efficiency.

Maintain excellent purification and conversion performance throughout the cycle and stability of the product:

Total HDS Ratio 90 More than;

Total HDM Ratio 95 More than.

4 (a), 4 (b) and 5 illustrate the present invention briefly. Figure 4 (a) shows how to use two pre-reactors, and Figure 4 (b) shows how to use three pre-reactors. The feedstock reaches the preliminary reactor (s) via pipe 1 and exits the reactor (s) via pipe 13. 5 shows the main HDM and HDS reactors: the feedstock withdrawn from the preliminary reactor (s) is injected via pipe 13 into the main HDM reactor 14 containing the fixed bed 26 of catalyst. The material discharged from the reactor 14 is withdrawn through the pipe 15 and then injected into a different hydrogenodemetallization reactor 16, where it passes through a fixed bed 27 of catalyst. The material exiting the reactor 16 is withdrawn through the pipe 17 and injected into the first hydrogen desulfurization reactor 18 where it passes through the fixed bed 28 of the catalyst. The material exiting the first hydrogen desulfurization reactor 18 flows through the pipe 19 to the second hydrogen desulfurization reactor 20, where it passes through the fixed bed 29 of the catalyst. The final product is withdrawn through pipe 21.

In the case shown in Figure 4 (a), the reserve zone has two reactors, and a preferred embodiment of this method comprises a series of cycles each consisting of four consecutive periods:

A first period of time in which the feedstock passes continuously through the reactor R1 followed by the reactor R2;

A second period in which the feedstock passes only through the reactor R2;

A third period of time during which the feedstock passes through reactor R2 followed by reactor R1;

The fourth time the feedstock passes through reactor R1 only.

The number of cycles performed in the preliminary reactor will depend on the operating cycle of the entire unit and the average frequency of exchanging reactors R1 and R2.

During the first period [step (a) of the process of the invention] the feedstock is fed via lines 1 and 21, which is a pre-reactor R1 containing a fixed bed A of catalyst. Valve 31 opened toward During this period, the valves 32, 33 and 35 are closed. The material discharged from the reactor (R1) is injected into the preliminary reactor (R2) containing the fixed bed (B) of catalyst via pipe (23), pipe (26) with open valve (34) and pipe (22). do. The material exiting the reactor R2 is injected into the main HDM reactor 14 shown in FIG. 5 via a pipe 24 and a pipe 13 comprising an open valve 36.

During the second period [step (b) of the method of the invention] the valves 31, 33, 34 and 35 are closed and the feedstock is opened towards line 1 and reactor R2. It is fed through a line 22 containing a valve 32. During this period, the material discharged from the reactor R2 is injected into the main HDM reactor 14 shown in FIG. 5 through a pipe 24 containing an open valve 36 and through a pipe 13.

During the third period (step (c) of the method of the invention) the valves 31, 34 and 36 are closed and the valves 32, 33 and 35 are opened. The feedstock is fed to reactor R2 via line 1 and line 22. The material discharged from the reactor R2 is injected into the preliminary reactor R1 through the pipe 24, the pipe 27 and the pipe 21. The material discharged from the reactor R1 is injected through the pipe 23 and the pipe 13 into the main HDM reactor 14 shown in FIG.

During the fourth period (step (d) of the method of the invention) the valves 32, 33, 34 and 36 are closed and the valves 31 and 35 are opened. The feedstock is fed to reactor R1 via line 1 and line 21. During this period, the material discharged from the reactor R1 is injected into the main HDM reactor 14 shown in FIG. 5 via a pipe 23 and a pipe 13.

In the case shown in Figure 4 (b), the preliminary zone has three reactors, a preferred embodiment of this method comprises a series of cycles each consisting of six consecutive periods:

A first period of time during which the feedstock passes through reactor R1 followed by reactor R2 and finally reactor R3;

A second period of time during which the feedstock passes through reactor R2 followed by reactor R3;

A third period of time during which the feedstock passes through reactor R2 followed by reactor R3 and finally reactor R1;

A fourth period of time during which the feedstock passes through reactor R3 followed by reactor R1;

A fifth period of time during which the feedstock passes through reactor R3 followed by reactor R1 and finally reactor R2;

The sixth time period in which the feedstock passes through reactor R1 followed by reactor R2.

The method as shown in FIG. 4 (b) operates in a manner equivalent to that described in connection with the method shown in FIG. 4 (a). During the first period, the valves 31, 34, 44, and 48 are open and the valves 32, 33, 35, 36, and 41 are closed. During the second period of time the valves 32, 44 and 48 are open and the valves 31, 33, 34, 35, 36 and 41 are closed. During the third period of time the valves 32, 33, 35 and 44 are opened and the valves 31, 34, 36, 41 and 48 are closed. During the fourth period, the valves 33, 35 and 41 are opened and the valves 31, 32, 34, 36, 44 and 48 are closed. During the fifth period, the valves 33, 34, 36, and 41 are opened and the valves 31, 32, 35, 44, and 48 are closed. During the sixth period, valves 31, 34, and 36 are open and valves 32, 33, 35, 41, 44, and 48 are closed.

In an advantageous embodiment, the unit has a treatment zone 30 (not shown) with suitable circulation, heating, cooling and separation means operating separately from the reaction zone. Using pipes and valves, these means displace the most upstream pre-reactor while performing operations to produce new catalyst contained in the pre-reactor that is exchanged just prior to being connected with the unit running continuously. These operations include preheating of the pre-reactor to be exchanged, loads of pressure and temperature necessary for the sulfiding and exchange of the catalyst contained therein. When the operation of exchanging the pre-reactor was performed by a suitable valve, the zone 30 would also perform an operation to treat the spent catalyst contained in the pre-reactor immediately after separation from the reaction zone. Such operations include washing and stripping the spent catalyst under suitable conditions and then cooling, followed by replacement of the new catalyst with an operation to drain the spent catalyst.

The catalyst in the preliminary reactor is preferably the same as the catalyst of the hydrogenodemetallization reactors 14 and 16.

It is also preferred that such catalysts are the catalysts described in EP-B-98764 herein. This catalyst is 0.1 to 30% by weight of carrier and metal oxide Contains one or more metals or metal compounds selected from group V, VI and VIII on the periodic table of elements in the form of a number of parallel aggregates. Each aggregate is formed of a number of small needle-like plates, and the plates of each aggregate are generally oriented radially with respect to one another and radially oriented with respect to the center of the aggregate.

The present invention more specifically relates to a process for treating heavy oil or heavy oil fractions with a high asphaltene content to convert to lighter fractions which are easier to transport or process by conventional purification processes. Coal hydrogenated oil can also be processed.

More specifically, the present invention is non-transportable and viscous, rich in metals, sulfur and asphaltenes and boiling point 520 at standard conditions. Heavy oils containing the above components are stable, easy to transport, low in metals, sulfur and asphaltenes, and have a boiling point of 520 at standard conditions. Very low content, for example 20 weight The problem encountered in converting into the following hydrocarbon product is solved.

In the present invention, the feedstock is first mixed with hydrogen and subjected to hydrogenation viscosity reduction and then injected into the preliminary reactor.

In another embodiment of the invention, the material discharged from the demetallization step passes through two or more catalyst beds operating under hydrodesulfurization conditions, each layer being mounted in a reactor and the catalyst deactivated or occluded. The catalyst bed is bypassed.

That is, two or more HDS reactors can be used simultaneously, and when one of the catalyst beds for HDS is blocked, the reactor is temporarily shut down. The spent catalyst is then discharged and replaced with fresh catalyst, and the reactor starts operation again.

In another embodiment of the present invention, the material obtained in the outlet line of the final HDS reactor (line 21 in FIG. 5) is de-asalted using a solvent, for example a hydrocarbon solvent or a solvent mixture. The most used hydrocarbon solvents are paraffinic, olefinic or cycloalkane hydrocarbons (or hydrocarbon mixtures) having 3 to 7 carbon atoms. This treatment is generally 0.05 weight in accordance with AFNOR standard NF T 60115 It is carried out under conditions capable of providing a deasphalted product containing the following heptane-precipitated asphaltenes. The deasphalting treatment step may be performed according to the procedure described in Applicant's US Patent-A-4715946. The solvent / feedstock ratio is typically from about 3: 1 to about 4: 1 in volume ratio, each step constituting the overall deasphalting treatment operation (mixed-precipitating, asphaltenescent decantation, washing-asphaltene phase precipitation). The physico-chemical manipulation of will generally be performed separately.

Typically the solvent used to wash the asphaltene phase is the same solvent used in the precipitation step.

Generally, the feedstock to be deasphalted is mixed upstream of the catalyst for deasphalting and the heat exchanger, where the heat exchanger adjusts the temperature of the mixture to the level necessary to obtain good precipitation and gradient desquatting of asphaltenes.

The feedstock-solvent mixture preferably passes through the tubes of the heat exchanger but does not move towards the calender.

The residence time of the feedstock-solvent mixture in the mixing-precipitation zone is generally from about 5 seconds to about 5 minutes, preferably from about 20 seconds to about 2 minutes.

The residence time of the mixture in the gradient separation zone is typically from about 4 minutes to about 20 minutes.

The residence time of the mixture in the wash zone is typically from about 4 minutes to about 20 minutes.

The rate of rise of the mixture in the gradient separation zone and wash zone is typically about 1 / s or less, preferably about 0.5 / s or less

The temperature used in the wash zone will typically be lower than the temperature in the gradient separation zone. The temperature difference between the two zones is typically about 5 to about 50 to be.

The mixture discharged from the washing zone is generally recycled to the decanter separator and is preferably recycled upstream of the heat exchanger mounted in the inlet of the decanter separator zone.

The solvent / asphaltene phase ratio in the wash zone is generally from about 0.5: 1 to about 8: 1, preferably from about 1: 1 to about 5: 1.

The deasphalting treatment operation can comprise two steps, each of which consists of three processes: precipitation, decantation and washing. In this specific case, the temperature of each process in the first step is on average about 10 to about 40 than the temperature of the corresponding process in the second step. It is desirable to be low enough.

The dissolution used may be phenol, glycol or C ₁ -C ₆ alcohol. However, it is advantageous to use paraffinic and / or olefinic solvents having 4 to 6 carbon atoms.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of the present invention.

Example 1

Heavy fractions of the topped raw type (BE) or vacuum residue type (RSV) as described in Example 1 of Applicant's European Patent EP-B-113297, A having a "fish" structure in the HDM reactor, Type A catalysts such as A1, A2 or A3 were used and HDB reactors were treated with catalyst B.

In order to compare the advantages of the method according to the invention, the following describes the processing of feedstock in two types of methods:

Method I: using a conventional pinned layer comprising a second HDS step after the first HDM step;

Method II: The method according to the invention, i.e. comprising an HDS step using a fixed bed after the HDM step, wherein the HDM step has a fixed bed and at least one upstream of which two preliminary HDM reactors are preceded in series. Process according to the procedure described above in the HDM reactor. A type A catalyst as described in Example 1 of European Patent B-113297 is used in the preliminary reactor. The reactor in the HDM zone contains the same type A catalyst as used in the preliminary zone, and the reactor in the HDS zone contains catalyst B described in European Patent-B-113297.

The HDM catalyst used to treat RSV (vacuum residue) SAFANYIA is catalyst A3, and the HDM catalyst used to treat BE (topping raw type) ATHABASCA is catalyst A2.

When the catalyst in the upstream preliminary reactor was blocked by coke or sediment such that it lost activity and / or could no longer be used, it was separated, another reactor was connected to the unit and the feedstock was injected directly into the other reactor. . The upstream preliminary reactor is exchanged without stopping the unit, ie without affecting the operating efficiency of the unit. In addition, by the present invention, the VVH (speed / volume / hour) in each preliminary reactor is selected to maximize protection of the other reactors from metal and to maximize its operating cycle. Selected rates / volumes / hours for the preliminary reactors mean that the capacity of these reactors is in the range of approximately the same as the capacity of the main HDM or HDS reactors; This aspect is in contrast to other fixed bed processes that use smaller capacity preliminary reactors.

Table 1 below summarizes the main features of the treated feedstock. Table 2 below presents data comparing the method of the present invention with the prior art method for two different feedstocks. As a result of analyzing the obtained results, it can be seen that the method of the present invention can obtain higher operating efficiency than that obtained by the conventional fixed bed method; This advantage is more pronounced when processing feedstocks with higher metal content. Conventional fixed bed treatment methods are unable to process feedstocks having a metal content of greater than about 250 ppm by weight, while the method of the present invention can maintain long operating cycles and high operating efficiency. In the process of the invention, the catalyst recovered when exchanging the most upstream pre-reactor is highly saturated with metal; This aspect entails saving the catalyst consumption compared to the prior art methods. Thus, in the case of the hydrogenation of topping BOSCAN crude, the consumption of the catalyst is About 10 to about 50 weight For example, about 30 May be less. To compare the methods used, operating conditions were adjusted to obtain a maximum conversion that was compatible with the stability of the product, with an average HDM of 95-97. to be. The total VVH is comparable in both cases.

Example 2

Has the main features as shown in Table 1 above; Feedstocks having a metal content of 204-1330 ppm by weight were treated by the process of the present invention and the difficulty during the treatment was varied. Table 3 below shows the results obtained for the operating efficiency and the rate of use of the preliminary reactor during each successive operating cycle of the same period.

Claims (11)

During the first dehydrogenation step, the hydrocarbon feedstock and hydrogen are passed through one or more hydrodemetallization catalysts under hydrodemetallization conditions, and then the material discharged from the first step during the subsequent second step is hydrogenated. In a method comprising two or more steps of treating heavy hydrocarbon fractions containing asphaltenes, sulfur impurities, and metal impurities by passing through at least one hydrodesulfurization catalyst under desulfurization conditions, the hydrogenodemetallization step comprises at least one fixed bed. At least two preliminary hydrogenation metallization zones, arranged in series for circulation, comprising a continuous repetition of steps (b) and (c) defined below, wherein the hydrogenation metallization zone is This preceding method comprises the steps of (a) to (c): (a) one of the preliminary regions is inactivated or occluded Using all of the spare areas together for a period of time less than that required; (b) bypassing the inactivated and / or occluded preliminary zone, regenerating and / or replacing the catalyst contained therein with a new catalyst; And (c) reconnecting the preliminary zone from which the catalyst has been regenerated in step (b) and using all of the preliminary zones together for a period of time less than the time required for one of the preliminary zones to deactivate and / or occlude. 2. The process of claim 1, wherein all of the preliminary zones are used together during step (c), wherein the preliminary zone regenerating the catalyst in step (b) is reconnected in the same manner as it was connected before it was bypassed in step (b). Way. 2. The method of claim 1, further comprising: (a) using all of the spare zones together for a period of time that is less than the time required for the inactive and / or occluded spare zone located upstream to the flow direction of the entire feedstock to be treated; (b) directly injecting the feedstock into the preliminary zone located immediately after the preliminary zone located most upstream during step (a), bypassing the most upstream preliminary zone during step (a) and contained therein Regenerating and / or replacing the catalyst with a new catalyst; And (c) reconnecting all the preliminary zones regenerating the catalyst in step (b) downstream of the preliminary zones, and during the step (b), the preliminary zone most upstream to the flow direction of the entire feedstock to be treated is Using all of the preliminary regions together for a period of time less than or equal to the time required to inactivate and / or occlude. 4. The method of claim 1, wherein each reactor in the preliminary zone has a capacity approximately equal to each reactor of the hydrogenation demetallization zone or zones. 5. 4. The method of claim 1, wherein the total VVH in the reserve region in operation is from about 0.1 to about 2. 5. The method of claim 5, wherein the VVH is about 0.2 to about 1. 4. The catalyst according to any one of claims 1 to 3, wherein the catalyst used in the preliminary zone comprises 0.1 to 30 wt% of the carrier and the metal oxide. At least one metal or metal compound selected from at least one of Groups V, VI and VII on the periodic table of elements, wherein the metal or metal compound is in the form of a number of parallel agglomerates, each agglomerate having a plurality of small needles Consisting of plates, wherein the plates of each aggregate are oriented radially with respect to one another and radially with respect to the center of the aggregate. The operation of any one of claims 1 to 3, wherein the preliminary zone is connected to a treatment zone adapted to treat catalyst contained in the non-operating preliminary zone under a pressure of 10 to 50 bar to stop operation of the unit. A way to swap spare areas without running. 4. The process according to any one of claims 1 to 3, wherein for the purpose of treating a feedstock comprising heavy oil or a heavy oil fraction containing asphaltenes, the feedstock is first mixed with hydrogen prior to feeding the feedstock to the preliminary zone. How to reduce viscosity. 4. The process according to any one of claims 1 to 3, wherein the effluent obtained at the outlet of the final hydrodesulfurization reactor is deasphalted using a solvent or solvent mixture. The process of any one of claims 1 to 3, wherein the effluent from the demetallization step is passed through two or more catalysts operating under hydrodesulfurization conditions, each of which is equipped in a reactor and the catalyst is burned. Bypassing the catalyst layer when activated or occluded.