A method and system for hydrogenating residual oil

Abstract

The present invention relates to the field of residue oil hydrogenation, and discloses a residue oil hydrogenation method and system. The method comprises: introducing a residue oil feedstock into a hydrogenation pretreatment reaction zone provided with N reaction units connected in parallel to carry out a hydrogenation pretreatment reaction; introducing the effluent of the hydrogenation pretreatment reaction into a main hydrogenation reaction zone to carry out a hydrogenation reaction; wherein N is an integer ≥ 2, and when the pressure drop of any reactor in the N reaction units connected in parallel in the hydrogenation pretreatment reaction zone reaches 60% to 100% of the reactor pressure drop limit value, dynamically introducing part of the flow entering the reactor into the first reactor downstream of the reactor in the liquid phase flow direction, so that the pressure drop of the reactor is controlled to be 0.1 MPa-P max MPa, the P max The invention has the advantages of high reactor utilization, simple operation and long operation cycle.

Description

Technical Field

[0001] The present invention relates to the field of residual oil hydrogenation, and in particular to a residual oil hydrogenation method and a residual oil hydrogenation system. Background Art

[0002] The combination of fixed-bed residue hydrotreating and catalytic cracking is one of the most mature and efficient processes for heavy oil conversion. However, the greatest challenges of fixed-bed residue hydrotreating lie in improving feedstock adaptability and maintaining long-term operation cycles. Currently, the operating cycle of fixed-bed residue hydrotreating units is typically one to two years, which cannot match the three to four-year operating cycle of catalytic cracking units. Frequent shutdowns for residue hydrotreating units severely impact refinery profitability.

[0003] The main factors affecting the operating cycle of a fixed-bed residue oil hydrotreating unit include: (1) catalyst metal (Ni+V) deposition and deactivation; (2) catalyst carbon deposition and deactivation; (3) reactor pressure difference increases beyond the limit; (4) hot spots appear in the catalyst bed, and the local temperature exceeds the limit.

[0004] To address these problems, an effective technical means to extend the operating cycle of the residue hydrotreating unit is to adopt more advanced protection reactor technology.

[0005] CN1484684A discloses a method for hydrotreating heavy hydrocarbon fractions using replaceable and short-circuitable reactors. The method involves hydrotreating heavy hydrocarbon fractions in a first hydrodemetallization section and then in a second hydrodesulfurization section, wherein the effluent from the first section passes through the second hydrodesulfurization section. The hydrodemetallization section is preceded by at least one protected zone. The hydrotreating method comprises the following steps: a) a step in which a protected zone is used; b) a step during which the protected zone is short-circuited and the catalyst contained in the section is regenerated and / or replaced; c) a step during which the protected zone, which has been regenerated and / or replaced, is reconnected; and d) a step in which at least one reactor in the hydrodemetallization section and / or hydrodesulfurization section can be short-circuited and the catalyst contained in the section can be regenerated and / or replaced. This method involves a complex switching process and significantly increases investment.

[0006] CN104119952A discloses a method for hydrotreating hydrocarbon oil, comprising: contacting a hydrocarbon oil feedstock and hydrogen with multiple hydrogenation catalyst beds in a hydrotreating unit; alternating between a primary and a backup hydrotreating reactor, wherein the primary reactor's online time is greater than the backup reactor's. This method utilizes two guard reactors, one large and one small, which improves reactor utilization efficiency, but the reactors are still not always fully utilized.

[0007] CN103059927A discloses a method for hydrotreating heavy oil products. This method removes the first hydrogenation reactor. When the pressure drop in the first hydrogenation reactor reaches an upper limit or the hotspot temperature is too high, the feedstock and hydrogen enter the second hydrogenation reactor, extending the device's operating cycle. This method can cause the guard reactor to be unusable for a long time, and during the complete removal of the guard reactor, there is a risk of overheating.

[0008] CN108018084A discloses a heavy oil hydroprocessing method for improving catalyst utilization. The method employs two parallel reactors in the hydroprocessing pretreatment reaction zone and operates at high temperature, allowing the catalyst in the main reaction zone to be regenerated and reused after one cycle. However, this method does not reduce the number of shutdowns of the residual oil hydroprocessing unit and still seriously impacts the economic benefits of the refinery. Summary of the Invention

[0009] The purpose of the present invention is to overcome the shortcoming of the existing hydrogenation method in processing residual oil raw materials, that is, the operating cycle is short.

[0010] To achieve the above-mentioned object, the present invention provides a method for hydrogenating residual oil in a first aspect, the method comprising: introducing a residual oil feedstock into a hydropretreatment reaction zone provided with N reaction units connected in parallel, contacting the feedstock with a hydropretreatment catalyst, and performing a hydropretreatment reaction; introducing the hydropretreatment reaction effluent into a hydrotreatment main reaction zone, contacting the feedstock with a hydrotreatment catalyst, and performing a hydrotreatment reaction;

[0011] Wherein, N is an integer ≥ 2, and

[0012] When the pressure drop of any reactor in the N reaction units connected in parallel in the hydropretreatment reaction zone reaches 60% to 100% of the reactor pressure drop limit value, part of the flow entering the reactor is dynamically introduced into the first reactor downstream of the reactor along the liquid phase flow direction, so that the pressure drop of the reactor is controlled to 0.1 MPa-P max MPa, the P max is the pressure drop limit value of the corresponding reactor.

[0013] A second aspect of the present invention provides a system for hydrogenating residual oil, the system comprising:

[0014] A hydropretreatment reaction zone, for performing a hydropretreatment reaction on a residual oil feedstock, the reaction zone comprising a feed main and N reaction units arranged in parallel, where N is an integer ≥ 2, the feed main and the N parallel reaction units being connected via N feed pipelines, each of the N parallel reaction units being connected in series with at least one fixed-bed reactor, and the feed pipeline of each fixed-bed reactor comprising at least one three-way valve with adjustable opening, the first end of the three-way valve being connected to the feed pipeline of an upstream material, the second end being connected to the feed pipeline of the reaction unit, and the third end being connected to the feed pipeline of the first reaction unit downstream of the reaction unit in the direction of liquid phase flow;

[0015] The reaction effluent from the hydropretreatment reaction zone is introduced into the hydroprocessing main reaction zone through the residue hydropretreatment product pipeline for hydroprocessing reaction. The hydroprocessing main reaction zone is provided with one or at least two reactors connected in series.

[0016] Compared with the prior art, the method provided by the present invention has the following advantages:

[0017] (1) The present invention reduces the logistics velocity of each reactor in the hydrogenation pretreatment reaction zone by arranging N reaction units in parallel in the hydrogenation pretreatment reaction zone, thereby reducing the initial pressure drop of each reactor in the hydrogenation pretreatment reaction zone, and at the same time increases the catalyst volume in the hydrogenation pretreatment reaction zone, improves its impurity tolerance capacity, and thus delays the pressure drop increase rate in the hydrogenation pretreatment reaction zone.

[0018] (2) The present invention dynamically adjusts the proportion of materials entering each reactor according to the pressure drop of each reactor in the hydrogenation pretreatment reaction zone, thereby avoiding the risk of overheating during the complete removal of the protective reactor in the conventional removable process. At the same time, all reactors have logistics passing through them during the entire operation cycle, maximizing the role of each reactor.

[0019] (3) The present invention also avoids various problems existing in existing protection reactor technologies, such as short operating cycle, and has the advantages of high reactor utilization, simple operation and long operating cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a process flow diagram of a method for hydrogenating residual oil and a system for hydrogenating residual oil according to a preferred embodiment of the present invention.

[0021] Description of Reference Numerals

[0022] 1. Residue oil feedstock; 2-1. Three-way valve A; 2-2. Three-way valve B; 3-1. Reactor (R1); 3-2. Reactor (R2); 4. Hydrogenation pretreatment reaction effluent; 5-1. Fixed bed reactor (R3); 5-2. Fixed bed reactor (R4); 5-3. Fixed bed reactor (R5); 5-4. Fixed bed reactor (R6); 6. Hydrogenation treatment effluent. DETAILED DESCRIPTION

[0023] The endpoints of the ranges and any values disclosed herein are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0024] As described above, the first aspect of the present invention provides a method for hydrogenating residual oil, comprising: introducing a residual oil feedstock into a hydropretreatment reaction zone provided with N reaction units connected in parallel, contacting the feedstock with a hydropretreatment catalyst, and performing a hydropretreatment reaction; introducing the hydropretreatment reaction effluent into a main hydrotreatment reaction zone, contacting the feedstock with a hydrotreatment catalyst, and performing a hydrotreatment reaction;

[0025] Wherein, N is an integer ≥ 2, and

[0026] When the pressure drop of any reactor in the N reaction units connected in parallel in the hydroprocessing pretreatment reaction zone reaches 60% to 100% of the reactor pressure drop limit value, part of the flow entering the reactor is dynamically introduced into the first reactor downstream of the reactor along the liquid phase flow direction (that is, introduced into the hydroprocessing main reaction zone) so that the pressure drop of the reactor is controlled to 0.1 MPa-P max MPa, the P max is the pressure drop limit value of the corresponding reactor.

[0027] Preferably, the pressure drop of each reactor in the hydrogenation pretreatment reaction zone is controlled to be 0.3 MPa-P max MPa.

[0028] Preferably, the hydroprocessing main reaction zone is provided with at least two reactors connected in series.

[0029] According to a preferred embodiment, when the pressure drop of the first reactor in the main reaction zone of the hydroprocessing reaches 60% to 100% of the reactor pressure drop limit value, part of the flow entering the reactor is dynamically introduced into the first reactor downstream of the reactor along the liquid phase flow direction, so that the pressure drop of the reactor is controlled to 0.1 MPa-P maxMPa, the P max is the pressure drop limit value of the corresponding reactor.

[0030] Preferably, the pressure drop of the first reactor in the main hydroprocessing reaction zone is controlled to be 0.3 MPa-P max MPa.

[0031] Preferably, the hydrogenation pretreatment catalyst comprises a hydrogenation protection catalyst and a hydrodemetallization catalyst sequentially arranged along the liquid phase flow direction.

[0032] More preferably, the hydroprocessing catalyst contains a carrier and an active component supported on the carrier, the carrier is selected from at least one of alumina, silica and titanium oxide, the active component is a Group VIB metal and / or a Group VIII metal, and the content of the active component is 0 to 20% by weight, calculated as oxide, based on the total weight of the hydroprocessing catalyst, with the balance being the carrier.

[0033] Particularly preferably, in the hydropretreatment catalyst, the active component is selected from at least one of nickel, cobalt, molybdenum and tungsten.

[0034] Preferably, the average particle size of the hydrogenation pretreatment catalyst is 1.1 to 50.0 mm, and the average pore size is 10 to 400 nm.

[0035] Preferably, the pore volume of the hydrogenation pretreatment catalyst is 0.5 to 1.5 mL / g, and the specific surface area is 50 to 350 m 2 / g.

[0036] Preferably, based on the total catalysts in the hydroprocessing pretreatment reaction zone and the hydroprocessing main reaction zone, the loading volume fraction of the hydroprocessing pretreatment catalyst is 10% to 50%.

[0037] Particularly preferably, in the hydrogenation pretreatment reaction zone, the catalyst grading in each reaction unit arranged in parallel is the same.

[0038] Preferably, the hydroprocessing catalyst contains a carrier and an active component supported on the carrier, the carrier is selected from at least one of alumina, silica and titanium oxide, the active component is a Group VIB metal and / or a Group VIII metal, and the content of the active component is 0 to 35% by weight, calculated as oxide, based on the total weight of the hydroprocessing catalyst, with the balance being the carrier.

[0039] Particularly preferably, in the hydroprocessing catalyst, the active component is selected from at least one of nickel, cobalt, molybdenum and tungsten.

[0040] Preferably, the average particle size of the hydroprocessing catalyst is 0.8 to 50 mm, and the average pore size is 7 to 400 nm.

[0041] Preferably, the bulk density of the hydroprocessing catalyst is 0.3 to 1.2 g / cm 3 , with a specific surface area of 50 to 400 m 2 / g.

[0042] Preferably, the pore volume of the hydroprocessing catalyst is 0.4 to 1.4 mL / g.

[0043] More preferably, the hydroprocessing catalyst is selected from at least one of a hydroprotection catalyst, a hydrodemetallization catalyst and a hydrodesulfurization catalyst.

[0044] Preferably, the hydropretreatment catalyst and the hydropretreatment catalyst of the present invention may further contain an additive, for example, an oxide of phosphorus.

[0045] Preferably, the reaction conditions of the hydrotreating pretreatment reaction zone and the hydrotreating main reaction zone independently meet at least the following conditions: temperature of 300-460°C, reaction pressure of 6-25 MPa, hydrogen-to-oil volume ratio of 150-1500, total liquid hourly volume space velocity of 0.1-1 h -1 .

[0046] More preferably, the reaction conditions of the hydrotreating pretreatment reaction zone and the hydrotreating main reaction zone independently meet at least the following requirements: temperature of 350-420°C, reaction pressure of 12-20 MPa, hydrogen-to-oil volume ratio of 200-1000, total liquid hourly volume space velocity of 0.15-0.4 h -1 .

[0047] According to a preferred embodiment, 2 to 3 reaction units connected in parallel are provided in the hydrogenation pretreatment reaction zone.

[0048] Preferably, the reactor of the hydrogenation pretreatment reaction zone is selected from at least one of a downflow reactor, an upflow reactor and a counterflow reactor;

[0049] Preferably, the logistics directions of the reactors in the hydrogenation pretreatment reaction zone are the same, and all of them are downflow reactors, upflow reactors or counterflow reactors.

[0050] Particularly preferably, each of the parallel-connected reaction units in the hydrogenation pretreatment reaction zone is provided with 1 to 2 fixed-bed reactors.

[0051] Preferably, the reactor in the main hydroprocessing reaction zone is a fixed bed reactor.

[0052] More preferably, the reactor in the hydroprocessing main reaction zone is selected from at least one of a downflow reactor, an upflow reactor and a counterflow reactor.

[0053] Preferably, the residual oil feedstock is selected from at least one of deasphalted oil, coker gas oil, catalytic light cycle oil, catalytic heavy cycle oil, coker gas oil, coal liquefaction heavy oil, coal tar, atmospheric residue oil and vacuum residue oil.

[0054] A second aspect of the present invention provides a system for hydrogenating residual oil, the system comprising:

[0055] A hydropretreatment reaction zone, for performing a hydropretreatment reaction on a residual oil feedstock, the reaction zone comprising a feed main and N reaction units arranged in parallel, where N is an integer ≥ 2, the feed main and the N parallel reaction units being connected via N feed pipelines, each of the N parallel reaction units being connected in series with at least one fixed-bed reactor, and the feed pipeline of each fixed-bed reactor comprising at least one three-way valve with adjustable opening, the first end of the three-way valve being connected to the feed pipeline of an upstream material, the second end being connected to the feed pipeline of the reaction unit, and the third end being connected to the feed pipeline of the first reaction unit downstream of the reaction unit in the direction of liquid phase flow;

[0056] The reaction effluent from the hydropretreatment reaction zone is introduced into the hydroprocessing main reaction zone through the residue hydropretreatment product pipeline for hydroprocessing reaction. The hydroprocessing main reaction zone is provided with one or at least two reactors connected in series.

[0057] Preferably, the feed pipeline of the first reactor in the main reaction zone of the hydroprocessing includes at least one three-way valve with adjustable opening, the first end of the three-way valve is connected to the feed pipeline of the upstream material, the second end is connected to the feed pipeline of the reactor, and the third end is connected to the feed pipeline of the first reactor downstream of the reactor along the liquid phase logistics direction.

[0058] According to a preferred embodiment, before the residual oil feedstock is introduced into the hydropretreatment reaction zone, the residual oil feedstock is first subjected to heat exchange and / or preheating treatment.

[0059] The present invention has no particular limitation on the specific manner of heat exchange or preheating treatment, and known operations may be used. The present invention will not be described in detail herein, and those skilled in the art should not interpret this as a limitation on the present invention.

[0060] According to another preferred embodiment, the effluent from the hydroprocessing reaction is subjected to separation treatment.

[0061] The present invention has no particular limitation on the specific manner of the separation treatment, and known operations may be used. The present invention will not be described in detail herein, and those skilled in the art should not understand this as a limitation on the present invention.

[0062] In the present invention, it is preferred that the reactants for the hydrogenation pretreatment reaction and the hydrotreatment reaction further include hydrogen.

[0063] The present invention has no particular limitation on the flow rate and introduction method of the hydrogen. Known operations can be used. The present invention will not be described in detail here, and those skilled in the art should not understand this as a limitation on the present invention.

[0064] In the present invention, the reactor pressure drop limit is affected by factors such as the reactor material, manufacturing process, and reactor internal component configuration, and is provided by the reactor manufacturer. The method of the present invention is not particularly limited thereto; illustratively, the reactor pressure drop limit is 0.7 MPa.

[0065] According to a particularly preferred embodiment, the method of the present invention adopts Figure 1 The process shown is carried out, specifically:

[0066] In the presence of hydrogen, the residual oil feedstock 1 is divided into two streams and then introduced into two parallel-connected reactors (R1) 3-1 and reactor (R2) 3-2 through three-way valve A 2-1 and three-way valve B 2-2, respectively, to undergo a hydrogenation pretreatment reaction with the hydrogenation pretreatment catalyst in each reactor, and the hydrogenation pretreatment reaction effluent 4 is sequentially introduced into four fixed-bed reactors (R3) 5-1, fixed-bed reactor (R4) 5-2, fixed-bed reactor (R5) 5-3 and fixed-bed reactor (R6) 5-4 connected in series in the main hydrogenation reaction zone to undergo a hydrogenation reaction with the hydrogenation catalyst in each reactor, thereby obtaining a hydrogenation reaction effluent 6; when the pressure drop of the reactor (R1) 3-1 or the reactor (R2) 3-2 in the hydrogenation pretreatment reaction zone reaches 60% to 100% of the reactor pressure drop limit value, the three-way valve A 2-1 or the three-way valve B 2-2 is dynamically adjusted. 2-2 opening, dynamically introduce part of the flow entering the reactor directly into the main reaction zone of hydroprocessing, so that the pressure drop of the reactor is controlled to 0.1MPa-P max MPa.

[0067] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, all raw materials used can be obtained from commercial channels.

[0068] In the following examples, unless otherwise specified, the shutdown criteria for the residue oil hydrotreating system are when the pressure drop in any reactor in the reaction zone reaches 0.7 MPa or the reaction temperature reaches 410°C.

[0069] In the following examples, the reaction pressure in the reaction zone is expressed as hydrogen partial pressure.

[0070] The types and specific compositions of the catalysts used in the following examples are shown in Table 1, where G represents a hydrogenation protection catalyst, M represents a hydrodemetallization catalyst, and S represents a hydrodesulfurization catalyst.

[0071] Table 1

[0072] project G M S <![CDATA[MO3 / (wt%)]]> 5.6 8.4 15.2 NiO / (weight %) 1.1 1.5 3.5 Pore volume / (mL / g) 0.85 0.68 0.60 <![CDATA[Specific surface area / (m 2 / g)]]> 110 165 180 Average particle size / mm 3.0 1.3 1.0 Average pore size / nm 25 14 11

[0073] Example 1

[0074] In this embodiment, the hydrotreatment pretreatment reaction zone is provided with two reactors R1 and R2 connected in parallel, and the hydrotreatment main reaction zone is provided with two reactors R3 and R4 connected in series. The catalyst loading method of each reactor and the initial reaction conditions of the reaction zone are shown in Table 2. The specific process flow is as follows:

[0075] The residual oil feedstock and hydrogen were divided into two equal streams and introduced into reactor R1 and reactor R2 for hydroprocessing pretreatment reaction. The hydroprocessing pretreatment reaction effluents from each reactor were mixed and sequentially introduced into reactor R3 and reactor R4 in the hydroprocessing main reaction zone for hydroprocessing reaction. The properties of the hydroprocessing reaction effluents after 500 h of operation are shown in Table 3. Thereafter, during the operation of the device, the reaction temperatures of the hydroprocessing pretreatment reaction zone and the hydroprocessing main reaction zone were simultaneously increased to control the sulfur content of the hydroprocessing reaction effluent to no more than 0.45 wt%. Whenever the pressure drop in reactor R1 or reactor R2 reached 60% of the reactor limit value (0.7 MPa), the opening of the three-way valve before the pressure drop in reactor R1 or reactor R2 was adjusted, and part of the stream entering the reactor was introduced into reactor R3 to reduce the pressure drop in reactor R1 or reactor R2 to below 0.3 MPa.

[0076] At 17,500 hours of operation, the pressure drop of reactor R3 reached 0.7 MPa and the device was shut down.

[0077] Example 2

[0078] The process flow and parameters of this embodiment are the same as those of embodiment 1, except that:

[0079] Whenever the pressure drop of reactor R1 or reactor R2 reaches 80% of the reactor limit value (0.7 MPa), the opening of the three-way valve in front of reactor R1 or reactor R2 is adjusted, and part of the logistics entering the reactor is introduced into reactor R3 to reduce the pressure drop of reactor R1 or reactor R2 to below 0.4 MPa.

[0080] At 18200h of operation, the pressure drop of reactor R3 reached 0.7MPa and the device was shut down.

[0081] Example 3

[0082] The process flow and parameters of this embodiment are the same as those of embodiment 1, except that:

[0083] Whenever the pressure drop in any of reactors R1, R2, and R3 reaches 60% of the reactor limit (0.7 MPa), the three-way valve opening in front of the corresponding reactor is adjusted to redirect part of the flow entering that reactor into the first reactor downstream of that reactor in the direction of liquid flow, reducing the pressure drop in that reactor to below 0.3 MPa. The plant shutdown criteria are when the pressure drop in reactor R4 reaches 0.7 MPa or the reaction temperature reaches 410°C.

[0084] At 20300h, the reaction temperature reached 410℃ and the device was shut down.

[0085] Comparative Example 1

[0086] In this comparative example, a known process flow was adopted, and four reactors R1, R2, R3, and R4 were connected in series in the main hydroprocessing reaction zone. The catalyst loading method of each reactor and the initial reaction conditions of the reaction zone are shown in Table 2. The specific process flow is as follows:

[0087] The residual oil feedstock and hydrogen were sequentially introduced into reactors R1, R2, R3, and R4 for hydrotreating reactions. After 500 h of operation, the properties of the hydrotreating reaction effluent were shown in Table 3. Thereafter, the reaction temperature of the main hydrotreating reaction zone was simultaneously increased during the operation of the device to control the sulfur content of the hydrotreating reaction effluent to no more than 0.45 wt%.

[0088] When the operation lasted for 13600 hours, the pressure drop of reactor R1 reached 0.7 MPa and the device was shut down.

[0089] Comparative Example 2

[0090] In this comparative example, a known removable process flow was adopted, and four reactors R1, R2, R3, and R4 were connected in series in the main hydroprocessing reaction zone. The catalyst loading method of each reactor and the initial reaction conditions of the reaction zone are shown in Table 2. The specific process flow is as follows:

[0091] Residual oil feedstock and hydrogen were sequentially introduced into reactors R1, R2, R3, and R4 for hydroprocessing. After 500 hours of operation, the properties of the hydroprocessing effluent are shown in Table 3. The temperature of the main hydroprocessing reaction zone was then increased during operation to control the sulfur content of the hydroprocessing effluent to no more than 0.45% by weight. When the pressure drop in reactor R1 fell below 0.7 MPa, the three-way valve in front of reactor R1 completely shut down reactor R1, allowing the residual oil feedstock and hydrogen to flow entirely into reactor R2. The shutdown criteria for the system were a pressure drop of 0.7 MPa or a reaction temperature of 410°C in any of reactors R2, R3, or R4.

[0092] When the operation lasted for 15800 hours, the reaction temperature reached 410℃ and the device was shut down.

[0093] Table 2

[0094]

[0095]

[0096] It can be seen from the above results that the method of the present invention can extend the operating cycle of the residue oil hydrotreating unit.

[0097] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for hydrogenating residual oil, characterized in that: The method comprises: introducing a residual oil feedstock into a hydropretreatment reaction zone provided with N reaction units connected in parallel, contacting the feedstock with a hydropretreatment catalyst and performing a hydropretreatment reaction; introducing the hydropretreatment reaction effluent into a hydrotreatment main reaction zone, contacting the feedstock with a hydrotreatment catalyst and performing a hydrotreatment reaction; Wherein, N is an integer ≥ 2, and When the pressure drop of any reactor in the N reaction units connected in parallel in the hydropretreatment reaction zone reaches 60% to 100% of the reactor pressure drop limit value, part of the flow entering the reactor is dynamically introduced into the first reactor downstream of the reactor along the liquid phase flow direction, so that the pressure drop of the reactor is controlled to 0.1 MPa-P max MPa, the P max is the pressure drop limit value of the corresponding reactor; The hydroprocessing main reaction zone is provided with at least two reactors connected in series; when the pressure drop of the first reactor in the hydroprocessing main reaction zone reaches 60% to 100% of the reactor pressure drop limit value, part of the flow entering the reactor is dynamically introduced into the first reactor downstream of the reactor along the liquid phase flow direction, so that the pressure drop of the reactor is controlled to be 0.1 MPa-P max MPa, the P max is the pressure drop limit value of the corresponding reactor.

2. The method according to claim 1, wherein The pressure drop of each reactor in the hydrogenation pretreatment reaction zone is controlled to be 0.3 MPa-P max MPa.

3. The method according to claim 1 or 2, wherein: The pressure drop of the first reactor in the main reaction zone of the hydroprocessing is controlled to be 0.3 MPa-P max MPa.

4. The method according to claim 1 or 2, wherein: The hydrogenation pretreatment catalyst comprises a hydrogenation protection catalyst and a hydrogenation demetallization catalyst which are sequentially arranged along the liquid phase flow direction.

5. The method according to claim 1 or 2, wherein: The hydroprocessing pretreatment catalyst contains a carrier and an active component supported on the carrier, the carrier is selected from at least one of alumina, silica and titanium oxide, the active component is a Group VIB metal and / or a Group VIII metal, and the content of the active component is greater than 0 and less than or equal to 20% by weight, calculated as oxide, based on the total weight of the hydroprocessing pretreatment catalyst, with the balance being the carrier.

6. The method according to claim 5, wherein: The average particle size of the hydrogenation pretreatment catalyst is 1.1-50.0 mm, and the average pore size is 10-400 nm.

7. The method according to claim 1 or 2, wherein: Based on the total catalysts in the hydroprocessing pretreatment reaction zone and the hydroprocessing main reaction zone, the loading volume fraction of the hydroprocessing pretreatment catalyst is 10% to 50%.

8. The method according to claim 1 or 2, wherein: In the hydrogenation pretreatment reaction zone, the catalyst grading mode in each reaction unit arranged in parallel is the same.

9. The method according to claim 1 or 2, wherein: The hydroprocessing catalyst contains a carrier and an active component supported on the carrier, the carrier is selected from at least one of alumina, silica and titania, the active component is a Group VIB metal and / or a Group VIII metal, and the content of the active component, calculated as oxide, is greater than 0 and less than or equal to 35% by weight, based on the total weight of the hydroprocessing catalyst, with the balance being the carrier.

10. The method according to claim 9, wherein: The average particle size of the hydroprocessing catalyst is 0.8-50 mm, and the average pore size is 7-400 nm.

11. The method according to claim 10, wherein: The bulk density of the hydroprocessing catalyst is 0.3-1.2 g / cm 3 , with a specific surface area of 50~400m 2 / g.

12. The method according to claim 1 or 2, wherein: The reaction conditions of the hydrotreating pretreatment reaction zone and the hydrotreating main reaction zone independently meet at least the following requirements: temperature of 300-460°C, reaction pressure of 6-25 MPa, hydrogen-to-oil volume ratio of 150-1500, total liquid hourly volume space velocity of 0.1-1 h -1 .

13. The method according to claim 12, wherein: The reaction conditions of the hydrotreating pretreatment reaction zone and the hydrotreating main reaction zone independently meet at least the following requirements: temperature of 350-420°C, reaction pressure of 12-20 MPa, hydrogen-to-oil volume ratio of 200-1000, total liquid hourly volume space velocity of 0.15-0.4 h -1 .

14. The method according to claim 1 or 2, wherein: The hydrogenation pretreatment reaction zone is provided with 2 to 3 reaction units connected in parallel.

15. The method according to claim 1 or 2, wherein: The reactor of the hydrogenation pretreatment reaction zone is selected from at least one of a downflow reactor, an upflow reactor and a counterflow reactor.

16. The method according to claim 15, wherein The logistics directions of the reactors in the hydrogenation pretreatment reaction zone are the same, and all of them are downflow reactors, upflow reactors or counterflow reactors.

17. The method according to claim 1 or 2, wherein: Each of the parallel-connected reaction units in the hydrogenation pretreatment reaction zone is provided with 1 to 2 fixed-bed reactors.

18. The method according to claim 1 or 2, wherein: The reactor in the main reaction zone of the hydroprocessing is a fixed bed reactor.

19. The method according to claim 18, wherein The reactor of the main hydroprocessing reaction zone is selected from at least one of a downflow reactor, an upflow reactor and a counterflow reactor.

20. The method according to claim 1 or 2, wherein: The residual oil raw material is selected from at least one of atmospheric residual oil and vacuum residual oil.

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