Process for residue hydrotreatment and residue hydrotreatment system

Abstract

The present application relates to the field of residual oil hydrogenation, and discloses a residual oil hydrogenation treatment method and a residual oil hydrogenation system, the residual oil hydrogenation treatment method provided by the present application comprises the following steps: introducing residual oil raw material into a first hydrogenation treatment unit, a second hydrogenation treatment unit and a third hydrogenation treatment unit connected in sequence under hydrogenation conditions to perform a hydrogenation treatment reaction, and obtaining a hydrogenation treatment product.The reactor in the first hydrogenation treatment unit can be cut out or cut in from the residual oil hydrogenation system, thereby solving the problem of metal deposition saturation of the hydrogenation treatment catalyst in the reactor; the reactor of the second hydrogenation treatment unit is provided with a shunt structure, which can dynamically adjust the proportion of the material entering the reactor, thereby solving the problem of the increase of the pressure drop of the reactor.The present application also overcomes the defects of the existing residual oil hydrogenation treatment method and system, such as short operation cycle, and has the advantages of high reactor utilization rate, 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 treatment method and a residual oil hydrogenation system. Background Art

[0002] Fixed-bed residue hydrotreating, when combined with downstream units such as catalytic cracking, catalytic cracking, and delayed coking, is a core technology for heavy oil conversion, efficiently producing high-value products such as high-quality oils, light olefins, aromatics, and low-sulfur coke. However, due to factors such as catalyst metal saturation, catalyst coke deactivation, and reactor pressure differential exceeding limits, the current 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. This seriously impacts the economic benefits of refineries.

[0003] To address the above issues, an effective technical means to extend the operating cycle of the residue hydrotreating unit is to adopt more advanced guard reactor technology. Currently, the guard reactor technologies used in residue hydrotreating include but are not limited to: (1) removable fixed-bed reactors; (2) upflow reactors; (3) fixed-bed reactors with serial rotation; (4) fixed-bed reactors with parallel rotation; and (5) reactors with online catalyst replacement (including ebullating bed, slurry bed, and moving bed). However, there is room for improvement in the existing guard reactor technologies.

[0004] CN103059927A discloses a method for hydrotreating heavy oil products. The method uses a removable guard reactor connected in series with a subsequent reactor. When the pressure drop in the guard 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 cannot fundamentally solve the metal storage problem of residual oil hydrotreating units during long-term operation. However, it is more suitable for solving the problem of increased pressure drop in the guard reactor caused by iron and calcium deposition.

[0005] CN1484684A discloses a method for hydrotreating heavy hydrocarbon fractions using a replaceable reactor and a short-circuitable reactor. The method utilizes two guard reactors connected in series, and the two guard reactors can also be connected in countercurrent. During operation, the guard reactor with the lowest activity or the highest pressure drop is replaced each time. During this replacement, only one guard reactor is online. After the replacement, the series arrangement of the two guard reactors is adjusted so that the guard reactor with the lowest activity or the highest pressure drop is always located at the front of the flow path. This method requires the use of a large number of high-pressure switching valves, which complicates the switching process and significantly increases investment.

[0006] Therefore, in order to fully utilize the activity of all catalysts in the residue oil hydrogenation system and extend the operating cycle, it is necessary to develop new hydrogenation systems and corresponding hydroprocessing methods. Summary of the Invention

[0007] The purpose of the present invention is to overcome the defect of short operating cycle when processing residual oil raw materials in the existing hydrogenation method.

[0008] In order to achieve the above object, the first aspect of the present invention provides a method for hydrotreating residual oil, the method comprising:

[0009] Under hydrogenation conditions, the residual oil feedstock is introduced into a first hydroprocessing unit, a second hydroprocessing unit, and a third hydroprocessing unit connected in sequence to perform a hydroprocessing reaction to obtain a hydroprocessing product;

[0010] When the hydroprocessing catalyst in the first hydroprocessing unit needs to be replaced, the first hydroprocessing unit is disconnected so that the residual oil feedstock directly enters the second hydroprocessing unit, the catalyst in the first hydroprocessing unit is replaced, and then the first hydroprocessing unit is reconnected to participate in the hydroprocessing reaction; and

[0011] When the pressure drop of any reactor A in the second hydroprocessing unit reaches the pressure drop limit value P x When the feed flow rate of the reactor A is adjusted to L A and feed the material from the upstream of the reactor A at a feed rate of L B Entering the reactor B adjacent to the downstream of the reactor A, so that the pressure drop of each reactor in the second hydroprocessing unit and the third hydroprocessing unit is less than the maximum pressure drop value P max , where L A +L B =L max , the L max is the maximum feed flow rate of the reactor A;

[0012] When any one of the reactors in the second hydroprocessing unit and the third hydroprocessing unit reaches a shutdown condition, the hydroprocessing reaction is stopped.

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

[0014] a first hydroprocessing unit, a second hydroprocessing unit, and a third hydroprocessing unit connected in sequence, wherein the first hydroprocessing unit is connected to the inlet of the hydrogenation system via a pipeline;

[0015] The first hydroprocessing unit and the second hydroprocessing unit are connected in such a manner that the first hydroprocessing unit can be short-circuited in the hydrogenation system, so that the residual oil feedstock can directly enter the second hydroprocessing unit from the inlet of the hydrogenation system;

[0016] The feed inlet and / or upstream pipeline of any reactor A in the second hydroprocessing unit is provided with a splitter structure, so that the feed flow rate L entering the reactor A can be adjusted online. A , so that the material from the upstream of the reactor A is fed at a feed rate L B Enter the reactor B adjacent to the downstream of the reactor A.

[0017] Compared with the prior art, the method and system provided by the present invention have at least the following advantages:

[0018] (1) The first hydroprocessing unit and the second hydroprocessing unit connected in sequence can respectively solve the problem of metal deposition saturation and the problem of increased reactor pressure drop caused by carbon deposition during long-term operation of residual oil hydroprocessing;

[0019] (2) The present invention dynamically adjusts the ratio of materials entering each reactor according to the pressure drop of each reactor in the second hydroprocessing unit. On the one hand, it solves the problem of increased pressure drop in the reactor. On the other hand, it ensures that all reactors have material flow through them during the entire operation cycle, thus maximizing the function of each reactor.

[0020] (3) The present invention overcomes the defects of the existing residue oil hydrogenation system such as short operating cycle, and has the advantages of high reactor utilization, simple operation and long operating cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a process flow chart of a residual oil hydroprocessing method provided according to a particularly preferred embodiment.

[0022] Description of Reference Numerals

[0023] 1. Inlet; 2-1. High-pressure valve (A); 2-2. High-pressure valve (B); 2-3. High-pressure valve (C); 3. Reactor (R1); 4. First hydroprocessing effluent; 5. Three-way valve; 6. Reactor (R2); 7. Second hydroprocessing effluent 7; 8-1. Reactor (R3); 8-2. Reactor (R4); 8-3. Reactor (R5); 9. Hydroprocessing product. DETAILED DESCRIPTION

[0024] 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.

[0025] As mentioned above, the first aspect of the present invention provides a method for hydrotreating residual oil, the method comprising:

[0026] Under hydrogenation conditions, the residual oil feedstock is introduced into a first hydroprocessing unit, a second hydroprocessing unit, and a third hydroprocessing unit connected in sequence to perform a hydroprocessing reaction to obtain a hydroprocessing product;

[0027] When the hydroprocessing catalyst in the first hydroprocessing unit needs to be replaced, the first hydroprocessing unit is disconnected so that the residual oil feedstock directly enters the second hydroprocessing unit, the catalyst in the first hydroprocessing unit is replaced, and then the first hydroprocessing unit is reconnected to participate in the hydroprocessing reaction; and

[0028] When the pressure drop of any reactor A in the second hydroprocessing unit reaches the pressure drop limit value P x When the feed flow rate of the reactor A is adjusted to L A and feed the material from the upstream of the reactor A at a feed rate of L B Entering the reactor B adjacent to the downstream of the reactor A, so that the pressure drop of each reactor in the second hydroprocessing unit and the third hydroprocessing unit is less than the maximum pressure drop value P max , where L A +L B =L max , the L max is the maximum feed flow rate of the reactor A;

[0029] When any one of the reactors in the second hydroprocessing unit and the third hydroprocessing unit reaches a shutdown condition, the hydroprocessing reaction is stopped.

[0030] After systematic research and summary, the inventors of the present invention found that in order for the residual oil hydroprocessing system to truly achieve long-term operation, on the one hand, it is necessary to solve the problem of metal deposition and deactivation of the hydroprocessing catalyst in the protective reactor, and on the other hand, it is necessary to solve the problem of increased pressure drop in the reactor due to carbon deposition in the reactor in front of the main reaction. In the method for hydroprocessing of residual oil provided by the present invention, the reactor in the first reaction unit has a cut-out / cut-in mode, which can realize the replacement of the hydroprocessing catalyst without affecting the residual oil hydroprocessing process, thereby solving the problem that the hydroprocessing catalyst in the reactor cannot continue to operate due to metal deposition and deactivation, causing the entire residual oil hydroprocessing system to shut down; in addition, the feed end of the reactor of the second reaction unit has a diversion structure. By diverting the reactor in the second unit, the pressure drop of each reactor can be effectively controlled, solving the problem that the reactor of the second hydroprocessing unit cannot continue to operate due to increased pressure drop due to carbon deposition too early.

[0031] In the present application, according to a particularly preferred embodiment, the shutdown condition comprises any one of the following conditions:

[0032] (1) the pressure drop of any reactor in the second hydroprocessing unit and the third hydroprocessing unit reaches the maximum pressure drop value P max ;

[0033] (2) the reaction temperature of any reactor in the second hydroprocessing unit and the third hydroprocessing unit reaches the highest set temperature.

[0034] It should be noted that in the present application, the reactor of the first hydroprocessing unit can perform catalyst replacement treatment, generally, the pressure drop of the reactor of the first hydroprocessing unit will not reach the maximum pressure drop value P max ; the second hydroprocessing unit can control the pressure drop of the reactor by adjusting the feed flow rate of the reactor, generally, the pressure drop of the reactor of the second hydroprocessing unit will not reach the maximum pressure drop value P max ; and the pressure drop of the reactor of the third hydroprocessing unit almost does not reach the maximum pressure drop value P max . Therefore, in actual application, the present application generally takes the reaction temperature of any reactor in the second hydroprocessing unit and the third hydroprocessing unit reaching the highest set temperature as the shutdown condition, thereby prolonging the cycle of hydroprocessing.

[0035] It should also be noted that the hydrogenation condition is under the condition of adding hydrogen.

[0036] According to a particularly preferred embodiment, under the condition of introducing hydrogen into the first hydroprocessing unit, the residual oil feedstock is introduced into the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit connected in sequence to perform a hydroprocessing reaction, thereby obtaining a hydroprocessing product. The present application does not have special limitations on the flow rate and introduction method of the hydrogen, and known operations in the art can be used. The present application will not be described in detail here, and those skilled in the art should not understand it as a limitation on the present application.

[0037] It should be noted that in the present application, the maximum pressure drop value of the reactor is affected by factors such as reactor material, manufacturing process and reactor internal component setting, and the maximum pressure drop value of the reactor is provided by the reactor manufacturer. The method of the present application does not have special limitations, and exemplarily, the maximum pressure drop value of the reactor in the embodiment of the present application is 0.7 MPa.

[0038] Preferably, the pressure drop limit value P x satisfies 0.6 P max ≤ P x < P max; The maximum set temperature is 400℃~460℃.

[0039] According to a particularly preferred embodiment, during the hydroprocessing reaction, the pressure drop P of each reactor in the second hydroprocessing unit is n Controlled to 0.1MPa≤P n <P max Preferably, during the hydroprocessing reaction, the pressure drop P of each reactor in the second hydroprocessing unit n Controlled to 0.3MPa≤P n <P max .

[0040] According to a particularly preferred embodiment, based on the total volume of the hydroprocessing catalysts of the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit, the loading volume fraction of the hydroprocessing catalyst in the first hydroprocessing unit is 10% to 40%, and the loading volume fraction of the hydroprocessing catalyst in the second hydroprocessing unit is 10% to 40%.

[0041] According to a particularly preferred embodiment, the hydroprocessing catalysts loaded in the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit are each independently selected from a hydroprocessing catalyst A having the following characteristics:

[0042] The hydroprocessing catalyst A contains a carrier and an active component supported on the carrier; the carrier is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal element in the active component is selected from at least one of Group VIB metal elements and Group VIII metal elements; based on the total weight of the hydroprocessing catalyst A, the content of the active component is 0 to 35% by weight in terms of oxide.

[0043] Preferably, the active metal element is at least one element selected from nickel, cobalt, molybdenum and tungsten.

[0044] According to a particularly preferred embodiment, the hydroprocessing catalysts loaded in the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit independently meet the following conditions: an average particle size of 0.8 to 50 mm and an average pore size of 7 to 400 nm.

[0045] Preferably, the hydroprocessing catalysts loaded in the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit independently meet the following conditions: a bulk density of 0.3 to 1.2 g / cm 3 , with a specific surface area of ​​50 to 400 m2 / g, and the pore volume is 0.4~1.4mL / g.

[0046] In the present invention, the hydroprocessing catalyst is selected from at least one of a hydroprotection catalyst, a hydrodemetallization catalyst and a hydrodesulfurization catalyst.

[0047] It should be noted that the present invention has no requirements on the specific types of the hydroprotection catalyst, hydrodemetallization catalyst and hydrodesulfurization catalyst, as long as they meet the characteristics of the aforementioned hydroprocessing catalyst A.

[0048] Exemplarily, the carriers of the hydroprotection catalyst, the hydrodemetallization catalyst and the hydrodesulfurization catalyst are respectively selected from at least one of alumina, silicon oxide and titanium oxide, the active components of the hydroprotection catalyst are 5.6 wt% MoO3 and 1.1 wt% NiO, the active components of the hydrodemetallization catalyst are 8.4 wt% MoO3, 1.5 wt% NiO and 1.0 wt% P2O5, and the active components of the hydrodesulfurization catalyst are 15.2 wt% MoO3, 3.5 wt% NiO and 2.0 wt% P2O5.

[0049] For example, the pore volume of the hydrogenation protection catalyst is 0.85 mL / g and the specific surface area is 110 m 2 / g, average particle size is 3.0mm, average pore size is 25nm, and bulk density is 0.45g / cm 3 The pore volume of the hydrodemetallization catalyst is 0.68 mL / g and the specific surface area is 165 m 2 / g, average particle size is 1.3mm, average pore size is 14nm, and bulk density is 0.47g / cm 3 The hydrodesulfurization catalyst has a pore volume of 0.60 mL / g and a specific surface area of ​​180 m 2 / g, average particle size is 1.0mm, average pore size is 11nm, and bulk density is 0.63g / cm 3 .

[0050] According to a particularly preferred embodiment, along the direction of liquid phase logistics, the first hydroprocessing unit is sequentially loaded with a hydroprotection catalyst and a hydrodemetallization catalyst, the second hydroprocessing unit is sequentially loaded with the hydroprotection catalyst and the hydrodemetallization catalyst; and the third hydroprocessing unit is sequentially loaded with the hydroprotection catalyst, the hydrodemetallization catalyst and the hydrodesulfurization catalyst.

[0051] According to a particularly preferred embodiment, the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit each independently meet the following reaction 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 0.1-3 h -1 .

[0052] Preferably, the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit each independently meet the following reaction conditions: 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 0.15-2h -1 .

[0053] According to a particularly preferred embodiment, the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit are each independently equipped with one or at least two reactors connected in series. It should be noted that, along the direction of liquid phase logistics, the feed end of each reactor in the second hydroprocessing unit is connected to the discharge end of the previous reactor and the feed end of the next reactor via a three-way valve. That is, when the second hydroprocessing unit is equipped with at least two reactors, the reactors in the second hydroprocessing unit are connected both in series and in parallel.

[0054] According to a particularly preferred embodiment, the reactors of the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit are each independently selected from at least one of a downflow reactor, an upflow reactor and a counterflow reactor.

[0055] According to a particularly preferred embodiment, the residual oil feedstock is selected from at least one of deasphalted oil, coker gas oil, catalytic light cycle oil, catalytic heavy cycle oil, coal liquefaction heavy oil, coal tar, atmospheric residue oil and vacuum residue oil.

[0056] According to a particularly preferred embodiment, the method further comprises: subjecting the residual oil feedstock to a heat exchange treatment and / or a preheating treatment before introducing the residual oil feedstock into the first hydroprocessing unit.

[0057] The present invention has no particular limitation on the specific methods of the heat exchange treatment and preheating treatment. 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.

[0058] According to a particularly preferred embodiment, the method further comprises: separating and treating the effluent after the hydroprocessing reaction in the third processing unit to obtain the hydroprocessing product.

[0059] The present application does not have a particular limitation on the specific way of the separation treatment, and known operations can be adopted, for example, a fractionation treatment, etc., and the present application will not be described in detail here, and those skilled in the art should not be understood as a limitation on the present application.

[0060] According to a particularly preferred specific embodiment, the present application provides a residue hydroprocessing method, which is implemented by using a residue hydroprocessing system as shown in Figure 1 The process flow includes the following steps:

[0061] S1: under the hydrogenation condition, the residue feedstock is introduced into the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit connected in sequence through the inlet 1 to perform the hydrogenation treatment reaction, and the hydroprocessing product is obtained; specifically, the residue feedstock enters the reactor (R1) 3 through the high-pressure valve (A) 2-1, and performs the first hydroprocessing reaction with the hydroprocessing catalyst in the reactor (R1) 3 to obtain the first hydroprocessing effluent 4, the first hydroprocessing effluent 4 enters the reactor (R2) 6 through the high-pressure valve (C) 2-3 and the three-way valve 5 in sequence, and performs the second hydroprocessing reaction with the hydroprocessing catalyst in the reactor (R2) 6 to obtain the second hydroprocessing effluent 7, the second hydroprocessing effluent 7 enters the reactor (R3) 8-1, the reactor (R4) 8-2 and the reactor (R5) 8-3 of the third hydroprocessing unit in sequence through the pipeline, and performs the third hydroprocessing reaction with the hydroprocessing catalyst in each reactor respectively to obtain the hydroprocessing product 9. In this step, the high-pressure valve (B) 2-2 is closed.

[0062] S2: when the hydroprocessing catalyst in the reactor (R1) 3 needs to be replaced, the high-pressure valve (B) 2-2 is opened, the high-pressure valve (A) 2-1 and the high-pressure valve (C) 2-3 are closed, and the reactor (R1) 3 is cut out, so that the residue feedstock 1 enters the reactor (R2) 6 through the high-pressure valve (B) 2-2 and the three-way valve 5 to continue the reaction, and after the catalyst replacement treatment of the reactor (R1) 3, the reactor (R1) 3 is re-cut in, the high-pressure valve (A) 2-1 and the high-pressure valve (C) 2-3 are opened, and the high-pressure valve (B) 2-2 is closed to participate in the hydroprocessing reaction;

[0063] S3: when the pressure drop of the reactor (R2) 6 reaches the pressure drop limit value P x , the feed flow of the reactor (R2) 6 is dynamically adjusted to L A , and the material from the upstream of the reactor (R2) 6 is fed into the adjacent downstream reactor (R3) 8-1 of the reactor (R2) 6 at the feed flow L B , so that the pressure drop of each reactor in the second hydroprocessing unit and the third hydroprocessing unit is less than the maximum pressure drop value P max, where L A +L B =L max , the L max is the maximum feed flow rate of the reactor A, and the maximum pressure drop value P max is 0.7MPa, and the pressure drop limit value satisfies 0.42MPa≤P x <0.7MPa;

[0064] When the pressure drop of any reactor among reactor (R2) 6, reactor (R3) 8-1, reactor (R4) 8-2 and reactor (R5) 8-3 reaches the maximum pressure drop value of 0.7 MPa, or when the reaction temperature of any reactor among the second hydroprocessing unit and the third hydroprocessing unit reaches 410°C, the hydroprocessing reaction is stopped.

[0065] A second aspect of the present invention provides a residual oil hydrogenation system, the system comprising:

[0066] a first hydroprocessing unit, a second hydroprocessing unit, and a third hydroprocessing unit connected in sequence, wherein the first hydroprocessing unit is connected to the inlet of the hydrogenation system via a pipeline;

[0067] The first hydroprocessing unit and the second hydroprocessing unit are connected in such a manner that the first hydroprocessing unit can be short-circuited in the hydrogenation system, so that the residual oil feedstock can directly enter the second hydroprocessing unit from the inlet of the hydrogenation system;

[0068] The feed inlet and / or upstream pipeline of any reactor A in the second hydroprocessing unit is provided with a splitter structure, so that the feed flow rate L entering the reactor A can be adjusted online. A , so that the material from the upstream of the reactor A is fed at a feed rate L B Enter the reactor B adjacent to the downstream of the reactor A.

[0069] After systematic research and summary, the inventors of the present invention found that in order for the residual oil hydrogenation system to truly achieve long-term operation, on the one hand, it is necessary to solve the problem of metal deposition and deactivation of the catalyst in the protective reactor, and on the other hand, it is necessary to solve the problem of increased pressure drop in the reactor due to carbon deposition and the like in the front reactor of the main reaction zone. In the residual oil hydrogenation system provided by the present invention, the reactor in the first reaction unit has a cut-out / cut-in mode, which can realize the replacement of the hydrogenation catalyst without affecting the residual oil hydrogenation process, thereby solving the problem that the hydrogenation catalyst in the reactor cannot continue to operate due to metal deposition and deactivation, causing the entire residual oil hydrogenation system to shut down; in addition, the reactor feed end of the second reaction unit has a diversion structure. By diverting the reactor in the second unit, the pressure drop of each reactor can be effectively controlled, solving the problem that the reactor of the second hydroprocessing unit cannot continue to operate prematurely due to increased pressure drop due to carbon deposition and the like.

[0070] According to a particularly preferred embodiment, the first hydroprocessing unit and the second hydroprocessing unit are connected in the following manner: the feed end of the first hydroprocessing unit is connected to the feed end of the second hydroprocessing unit; and the discharge end of the first hydroprocessing unit is also connected to the feed end of the second hydroprocessing unit.

[0071] It should be noted that the feed end described in the present invention includes a feed port and an upstream pipeline, and the discharge end described in the present invention includes a discharge port and a discharge pipeline.

[0072] According to a particularly preferred embodiment, the diversion structure is a three-way valve, which is respectively connected to the upstream pipeline of the reactor A, the feed port of the reactor A, and the feed port of the reactor B. By adjusting the valve size of the three-way valve, the feed amount of the material from the upstream of the reactor A into the reactor A and the reactor B can be adjusted, thereby reducing the processing pressure of the reactor A on the material and controlling the pressure drop of the reactor A to not exceed the pressure drop limit value P x , to prevent the reactor A from being unable to continue operating due to premature pressure drop caused by carbon deposition, etc.

[0073] According to a particularly preferred embodiment, the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit each include one or at least two reactors connected in series. It should be noted that, along the liquid phase flow direction, the feed end of each reactor in the second hydroprocessing unit is connected to the discharge end of the previous reactor and the feed end of the next reactor via a three-way valve. That is, when the second hydroprocessing unit includes at least two reactors, the reactors in the second hydroprocessing unit are connected both in series and in parallel.

[0074] According to a particularly preferred embodiment, the reactors of the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit are each selected from at least one of a downflow reactor, an upflow reactor and a reverse flow reactor.

[0075] According to a particularly preferred embodiment, the residue hydroprocessing system provided by the present application comprises, as shown in Figure 1 Figure 1, a first hydroprocessing unit, a second hydroprocessing unit and a third hydroprocessing unit connected in sequence, wherein the first hydroprocessing unit comprises one reactor (R1) 3, the second hydroprocessing unit comprises one reactor (R2) 6, and the third hydroprocessing unit comprises three reactors (R3) 8-1, (R4) 8-2 and (R5) 8-3 connected in sequence.

[0076] The first hydroprocessing unit is connected to the inlet 1 of the hydroprocessing system by a pipeline, and the first hydroprocessing unit is connected to the second hydroprocessing unit in such a way that the first hydroprocessing unit can be short-circuited in the hydroprocessing system, so that the residue feedstock can directly enter the second hydroprocessing unit from the inlet 1 of the hydroprocessing system.

[0077] A split structure three-way valve 5 is provided on the pipeline upstream of the reactor (R2) 6 in the second hydroprocessing unit, so that the feed flow L A into the reactor (R2) 6 can be adjusted online. B The material from upstream of the reactor (R2) 6 enters the downstream adjacent reactor (R3) 8-1 of the reactor (R2) 6 at a feed flow L

[0078] The present application will be described in detail below by way of examples. In the following examples, various feedstocks used are available from commercial channels unless otherwise specified.

[0079] In the following examples, the residue feedstock is a mixture of atmospheric residue and vacuum residue, having a density of 0.981 g / cm 3 at 20°C, a carbon residue content of 12.6 wt%, a sulfur content of 4.02 wt%, and a metal (Ni+V) content of 100.6 μg / g.

[0080] In the following examples, the residue feedstock introduced into the residue hydroprocessing system is preheated.

[0081] In the following examples, the hydroprocessing product is obtained after separation treatment of the product after the residue hydroprocessing system.

[0082] In the following examples, each reactor is a downflow reactor, and the maximum pressure drop of each reactor is 0.7 MPa.

[0083] 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.

[0084] In the following examples, the reaction pressure in the reaction zone is expressed as hydrogen partial pressure.

[0085] In the following examples, along the liquid phase flow direction, the first hydroprocessing unit is sequentially loaded with a hydroprotection catalyst and a hydrodemetallization catalyst, the second hydroprocessing unit is sequentially loaded with the hydroprotection catalyst and the hydrodemetallization catalyst; the third hydroprocessing unit is sequentially loaded with the hydroprotection catalyst, the hydrodemetallization catalyst, and the hydrodesulfurization catalyst. The types and specific compositions of the hydroprocessing catalysts are shown in Table 1, where G represents a hydroprotection catalyst, M represents a hydrodemetallization catalyst, and S represents a hydrodesulfurization catalyst.

[0086] Table 1

[0087] Item G M S <![CDATA[MoO3 / (重量%)]]> 5.6 8.4 15.2 NiO / (wt%) 1.1 1.5 3.5 <![CDATA[P2O5 / (重量%)]]> - 1.0 2.0 SiO / (wt%) - - - Pore volume / (mL / g) 0.85 0.68 0.60 <![CDATA[比表面积 / (m 2 / g)]]> 110 165 180 Average particle size / mm 3.0 1.3 1.0 Average pore size / nm 25 14 11 Bulk density / g / cm 3 ]]> 0.45 0.47 0.63

[0088] Example 1

[0089] The residue oil hydrogenation system provided in this embodiment includes a first hydroprocessing unit, a second hydroprocessing unit, and a third hydroprocessing unit connected in sequence, and the first hydroprocessing unit is connected to the inlet of the hydrogenation system through a pipeline;

[0090] The first hydroprocessing unit and the second hydroprocessing unit are connected in such a manner that the first hydroprocessing unit can be short-circuited in the hydrogenation system, so that the residual oil feedstock can directly enter the second hydroprocessing unit from the inlet of the hydrogenation system;

[0091] The feed inlet and / or upstream pipeline of any reactor A in the second hydroprocessing unit is provided with a splitter structure, so that the feed flow rate L entering the reactor A can be adjusted online. A , so that the material from the upstream of the reactor A is fed at a feed rate L B Enter the reactor B adjacent to the downstream of the reactor A.

[0092] Among them, the first hydroprocessing unit is equipped with one reactor R1, the second hydroprocessing unit is equipped with one reactor R2, and the third hydroprocessing unit is equipped with two reactors connected in series, reactor R3 and reactor R4. The hydroprocessing catalyst loading method of each reactor and the initial reaction conditions of the reactor are shown in Table 2.

[0093] The residue oil hydrotreating method provided in this embodiment is implemented using the residue oil hydrotreating system provided in this embodiment. The specific process flow is as follows:

[0094] The residual oil feedstock and hydrogen were introduced into sequentially connected reactors R1, R2, R3, and R4 for a hydrotreatment reaction. After 500 hours of operation, the properties of the hydrotreated product were shown in Table 3. Subsequently, during the operation of the residual oil hydrogenation system, the reaction temperature of reactor R1 was increased to control the metal (Ni+V) mass fraction of the effluent after the hydrogenation reaction in reactor R1 to no more than 30 μg / g. Simultaneously, the reaction temperatures of reactors R2, R3, and R4 were simultaneously increased to control the sulfur content of the effluent from the hydrotreatment reaction to no more than 0.45 wt%.

[0095] Whenever the reaction temperature of reactor R1 reaches 410°C, reactor R1 is disconnected from the residue oil hydrogenation system and the hydrotreating catalyst is replaced. The residue oil feedstock and hydrogen are sequentially introduced into reactors R2, R3, and R4 for hydrotreating reactions. After reactors R2, R3, and R4 continue to operate for 480 hours and the hydrotreating catalyst in reactor R1 is replaced, reactor R1 is reinserted into the residue oil hydrogenation system and continues to operate according to the original temperature increase standard.

[0096] Whenever the pressure drop of reactor R2 reaches the pressure drop limit value of 0.42MPa (i.e. the maximum pressure drop value P max When the pressure drop of the reactor R2 is reduced to below 0.3 MPa, the opening of the three-way valve upstream of the reactor R2 is adjusted to introduce part of the stream upstream of the reactor 2 directly into the reactor R3.

[0097] At 26200h, the reaction temperature of reactor R2, reactor R3 and reactor R4 reached 410℃ and the residue oil hydrogenation system was shut down.

[0098] Example 2

[0099] The residue oil hydrogenation system, process flow and parameters of this embodiment are the same as those of Example 1, except that:

[0100] Whenever the pressure drop of reactor R2 reaches 0.56 MPa (i.e. 80% of the maximum pressure drop of 0.7 MPa), the opening of the three-way valve in front of reactor R2 is adjusted, and part of the flow entering the reactor is introduced into reactor R3 to reduce the pressure drop of reactor R2 to below 0.4 MPa.

[0101] At 27100h of operation, the reaction temperature of reactor R2, reactor R3 and reactor R4 reached 410°C and the device was shut down.

[0102] Comparative Example 1

[0103] The residue oil hydroprocessing system of this comparative example includes four reactors R1, R2, R3 and R4 connected in series. The loading method of the hydroprocessing catalyst in each reactor and the initial reaction conditions of the reactor are shown in Table 2. The specific process flow is as follows:

[0104] The residual oil feedstock and hydrogen were introduced into reactors R1, R2, R3, and R4, which were connected in series, for hydrotreatment reactions. After 500 h of operation, the properties of the hydrotreated products were shown in Table 3. Subsequently, during the operation of the system, the reaction temperatures of reactors R1, R2, R3, and R4 were simultaneously increased to control the sulfur content of the hydrotreatment reaction effluent to no more than 0.45 wt%.

[0105] When the operation lasted for 13,000 hours, the pressure drop of reactor R1 reached 0.7 MPa and the device was shut down.

[0106] Comparative Example 2

[0107] The residue oil hydroprocessing system of this comparative example includes four reactors R1, R2, R3, and R4 connected in series. The loading method of the hydroprocessing catalyst in each reactor and the initial reaction conditions of the reaction zone are shown in Table 2. The specific process flow is as follows:

[0108] The residual oil feedstock and hydrogen were introduced into reactors R1, R2, R3, and R4, which were connected in series, for hydrotreatment reactions. After 500 h of operation, the properties of the hydrotreated products were shown in Table 3. Subsequently, during the operation of the system, the reaction temperature of reactor R1 was increased to control the metal (Ni+V) mass fraction of the effluent after the hydrogenation reaction in reactor R1 to no more than 30 μg / g. At the same time, the reaction temperatures of reactors R2, R3, and R4 were simultaneously increased to control the sulfur content of the hydrotreatment reaction effluent to no more than 0.45 wt%. Whenever the reaction temperature of R1 reached 410°C, R1 was removed from the reaction system and the hydrotreatment catalyst was replaced. Simultaneously, the residual oil feedstock and hydrogen were introduced into reactors R2, R3, and R4 in sequence for hydrotreatment reactions. After reactors R2, R3, and R4 continued to operate for 480 h, and after the hydrotreatment catalyst in reactor R1 was replaced, reactor R1 was reinserted into the residual oil hydrogenation system and continued to operate according to the original temperature increase standard.

[0109] At 23600h, the pressure drop of reactor R2 reached 0.7MPa and the device was shut down.

[0110] Table 2

[0111]

[0112]

[0113] Table 3

[0114]

[0115] The above results show that the residue oil hydroprocessing method and system provided by the present invention have good residue oil hydroprocessing effect, and the processing cycle of the residue oil hydroprocessing system is greatly extended. In practical applications, the residue oil hydroprocessing efficiency is greatly improved.

[0116] 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 hydrotreating residual oil, characterized in that: The method comprises: Under hydrogenation conditions, the residual oil feedstock is introduced into a first hydroprocessing unit, a second hydroprocessing unit, and a third hydroprocessing unit connected in sequence to perform a hydroprocessing reaction to obtain a hydroprocessing product; When the hydroprocessing catalyst in the first hydroprocessing unit needs to be replaced, the first hydroprocessing unit is disconnected so that the residual oil feedstock directly enters the second hydroprocessing unit. After the catalyst in the first hydroprocessing unit is replaced, the first hydroprocessing unit is reconnected to participate in the hydroprocessing reaction; the first hydroprocessing unit is equipped with one reactor; and When the pressure drop of any reactor A in the second hydroprocessing unit reaches the pressure drop limit value P x When the feed flow rate of the reactor A is adjusted to L A and feed the material from the upstream of the reactor A at a feed rate of L B Entering the reactor B adjacent to the downstream of the reactor A, so that the pressure drop of each reactor in the second hydroprocessing unit and the third hydroprocessing unit is less than the maximum pressure drop value P max , where L A +L B =L max , the L max is the maximum feed flow rate of the reactor A; When any one of the reactors in the second hydroprocessing unit and the third hydroprocessing unit reaches a shutdown condition, stopping the hydroprocessing reaction; The pressure drop P of each reactor in the second hydroprocessing unit n Controlled to 0.3MPa≤P n <P max ; The pressure drop limit value P x Meet 0.6P max ≤P x <P max .

2. The method according to claim 1, characterized in that The shutdown conditions include any one of the following conditions: (1) The pressure drop of any reactor in the second hydroprocessing unit and the third hydroprocessing unit reaches the maximum pressure drop value P max ; (2) The reaction temperature of any one of the reactors in the second hydroprocessing unit and the third hydroprocessing unit reaches the maximum set temperature.

3. The method according to claim 2, characterized in that The maximum set temperature is 400°C~460°C.

4. The method according to any one of claims 1 to 3, characterized in that Based on the total volume of the hydroprocessing catalyst of the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit, the loading volume fraction of the hydroprocessing catalyst in the first hydroprocessing unit is 10% to 40%, and the loading volume fraction of the hydroprocessing catalyst in the second hydroprocessing unit is 10% to 40%.

5. The method according to any one of claims 1 to 3, characterized in that The hydroprocessing catalysts loaded in the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit are each independently selected from a hydroprocessing catalyst A having the following characteristics: The hydroprocessing catalyst A contains a carrier and an active component supported on the carrier; the carrier is selected from at least one of aluminum oxide, silicon oxide and titanium oxide, and the active metal element in the active component is selected from at least one of Group VIB metal elements and Group VIII metal elements; based on the total weight of the hydroprocessing catalyst A, the content of the active component in terms of oxide is greater than 0 and less than or equal to 35% by weight.

6. The method according to claim 5, characterized in that The active metal element is at least one element selected from nickel, cobalt, molybdenum and tungsten.

7. The method according to any one of claims 1 to 3, characterized in that The hydroprocessing catalysts loaded in the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit independently meet the following conditions: an average particle size of 0.8 to 50 mm, and an average pore size of 7 to 400 nm.

8. The method according to any one of claims 1 to 3, characterized in that The hydroprocessing catalysts loaded in the first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit independently meet the following conditions: the bulk density is 0.3-1.2 g / cm 3 , with a specific surface area of ​​50~400m 2 / g, and the pore volume is 0.4~1.4mL / g.

9. The method according to any one of claims 1 to 3, characterized in that The hydroprocessing catalyst is selected from at least one of a hydroprotection catalyst, a hydrodemetallization catalyst and a hydrodesulfurization catalyst.

10. The method according to claim 9, characterized in that Along the liquid phase flow direction, the first hydroprocessing unit is sequentially filled with a hydroprotection catalyst and a hydrodemetallization catalyst; The second hydroprocessing unit is sequentially filled with the hydroprotection catalyst and the hydrodemetallization catalyst; The third hydroprocessing unit is sequentially filled with the hydroprotection catalyst, the hydrodemetallization catalyst and the hydrodesulfurization catalyst.

11. The method according to any one of claims 1 to 3, characterized in that The first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit each independently meet the following reaction 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 0.1-3 h -1 .

12. The method according to claim 10, characterized in that The first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit each independently meet the following reaction conditions: 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 0.15-2h -1 .

13. The method according to any one of claims 1 to 3, characterized in that The second hydroprocessing unit and the third hydroprocessing unit are each independently provided with one reactor or at least two reactors connected in series.

14. The method according to any one of claims 1 to 3, characterized in that The reactors of the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit are each independently selected from at least one of a downflow reactor, an upflow reactor, and a counterflow reactor.

15. The method according to any one of claims 1 to 3, characterized in that The residual oil raw material is selected from at least one of atmospheric residual oil and vacuum residual oil.

16. The method according to any one of claims 1 to 3, characterized in that The method further includes: before introducing the residual oil feedstock into the first hydroprocessing unit, subjecting the residual oil feedstock to a heat exchange treatment.

17. The method according to any one of claims 1 to 3, characterized in that The method further includes: preheating the residual oil feedstock before introducing the residual oil feedstock into the first hydroprocessing unit.

18. The method according to any one of claims 1 to 3, characterized in that The method further includes: separating and treating the effluent after the hydroprocessing reaction in the third hydroprocessing unit to obtain the hydroprocessing product.

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