Residue hydrotreating process and system

Abstract

The present application relates to the field of residual oil hydrogenation, and discloses a residual oil hydrogenation treatment method and system, the method for residual oil hydrogenation treatment provided by the present application comprises the following steps: introducing residual oil raw material into first hydrogenation treatment unit, second hydrogenation treatment unit and third hydrogenation treatment unit connected in sequence under hydrogenation conditions to carry out hydrogenation treatment reaction, and obtaining hydrogenation treatment product.The first hydrogenation treatment unit is provided with at least two reactors connected in parallel and capable of being alternately online, which solves the problem of metal deposition saturation of 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 material entering the reactor, and solves the problem of rising pressure drop of the reactor.The method for residual oil hydrogenation treatment and the residual oil hydrogenation system provided by the present application overcome the defects of short operation cycle of the existing residual oil hydrogenation treatment method and system, and have the advantage of long operation cycle.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of residue hydroprocessing, in particular to a residue hydroprocessing method and system. BACKGROUND

[0002] Fixed bed residue hydroprocessing combined with downstream units such as catalytic cracking, catalytic cracking and delayed coking can efficiently produce high-quality oil, low-carbon olefins, aromatics and low-sulfur coke, etc. high-value products, is one of the core technologies of heavy oil conversion. However, due to factors such as catalyst metal deposition saturation, catalyst carbon deposition deactivation, and reactor pressure difference exceeding the limited value, the current operation cycle of the fixed bed residue hydroprocessing unit is usually 1-2 years, which cannot match the 3-4 year operation cycle of the catalytic cracking unit, which seriously affects the economic benefit of the refinery.

[0003] In view of the above problems, an effective technical means to extend the operation cycle of the residue hydroprocessing unit is to use more advanced guard reactor technology. The current guard reactor technology used in residue hydroprocessing includes but is not limited to: (1) removable fixed bed reactor; (2) upflow reactor; (3) series of replaceable fixed bed reactors; (4) parallel replaceable fixed bed reactors; (5) reactors that can replace catalysts online (including ebullated bed, slurry bed and moving bed, etc.). However, there is still room for improvement in the existing guard reactor technology.

[0004] CN103059927A discloses a heavy oil hydroprocessing method, which uses a removable guard reactor, the guard reactor is connected in series with the subsequent reactor, when the pressure drop in the guard reactor reaches the upper limit or the hot spot temperature is too high, the raw material and hydrogen enter the second hydrogenation reactor, extending the operation cycle of the unit. This method will result in the guard reactor being unable to be used for a long time, and cannot fundamentally solve the metal capacity problem of the residue hydroprocessing unit during long-term operation, and is more suitable for solving the problem of rising pressure drop in the guard reactor caused by iron and calcium deposition.

[0005] CN107629816A discloses a method for hydroprocessing of poor quality heavy oil, which uses two upflow reactors connected in series or in parallel as the guard reactor of the fixed bed reactor, which can meet the needs of improving the impurity removal rate and extending the reactor cycle. However, since the particle size of the upflow catalyst is usually large, the diffusion performance of the residue macromolecules in the upflow catalyst is poor, so the metal capacity of this method is not good, and the ability to extend the operation cycle is limited.

[0006] Therefore, in order to fully utilize the activity of all catalysts in the residue hydroprocessing system and extend the operation cycle, it is necessary to develop a new hydrogenation system and the corresponding hydroprocessing method. SUMMARY

[0007] The present application aims to overcome the short continuous operation cycle defect of the existing hydrogenation method for processing residual oil feedstock.

[0008] To achieve the above-mentioned purpose, one aspect of the present application provides a residual oil hydroprocessing method, which comprises:

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

[0010] The first hydroprocessing unit is provided with at least two reactors connected in parallel, at least one of the reactors is kept in an online state, and at least one is kept in an offline state, when the hydroprocessing catalyst in any reactor C kept in the online state needs to be replaced, the reactor C is taken offline, and any reactor D kept in the offline state is put online to participate in the hydroprocessing reaction, and the reactor C is subjected to catalyst replacement treatment to replace the reactor which needs to replace the hydroprocessing catalyst in the future; and

[0011] When the pressure drop of any reactor A in the second hydroprocessing unit reaches the pressure drop limit value P x , the feed flow rate of the reactor A is adjusted to L A , and the material from the upstream of the reactor A is introduced into the adjacent downstream reactor B of the reactor A at the feed flow rate 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 , wherein L A +L B =L max , the L max is the maximum feed flow rate of the reactor A; and,

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

[0013] The second aspect of the present application provides a residual oil hydrogenation system, which comprises:

[0014] The first hydroprocessing unit, the second hydroprocessing unit and the third hydroprocessing unit connected in sequence, and the first hydroprocessing unit is connected with the inlet of the hydrogenation system through a pipeline;

[0015] The first hydroprocessing unit is provided with at least two reactors connected in parallel, and the feed end and the discharge end of each reactor are respectively provided with a switch, so that each reactor can be independently put online or offline;

[0016] The feed end of any reactor A in the second hydroprocessing unit is provided with a flow splitting structure, so that the feed flow L into the reactor A can be adjusted online A , so that the material from upstream of the reactor A enters the downstream adjacent reactor B at a feed flow L B .

[0017] The method and system provided by the present application have at least the following advantages compared with the prior art:

[0018] (1) The first hydroprocessing unit is provided with at least two reactors connected in parallel, at least one of which is kept online and at least one of which is kept offline, so that when the online reactor needs to be replaced with a hydroprocessing catalyst, the offline reactor can be put online to replace the offline reactor, solving the problem of stopping the hydroprocessing reaction due to saturation of metal deposition of the hydroprocessing catalyst in the reactor;

[0019] (2) The present application dynamically adjusts the proportion of the material entering each reactor according to the pressure drop of each reactor in the second hydroprocessing unit, which on the one hand solves the problem of rising pressure drop of the reactor caused by carbon deposition and other factors of the hydroprocessing catalyst in the reactor, and on the other hand all reactors have material passing through during the entire operation period, maximizing the role of each reactor;

[0020] (3) The present application simultaneously overcomes the defects of short operation period of the existing residue hydroprocessing system, and has the advantages of simple operation and long operation period. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a process flow diagram of the residue hydroprocessing method provided by the present application according to a particularly preferred specific embodiment.

[0022] REFERENCE NUMERALS

[0023] 1, inlet; 2-1, high-pressure valve (A); 2-2, high-pressure valve (B); 2-3, high-pressure valve (C); 2-4, high-pressure valve (D); 3-1, reactor (R1); 3-2, reactor (R2); 4, first hydroprocessing effluent; 5, three-way valve; 6, reactor (R3); 7, second hydroprocessing effluent; 8-1, reactor (R4); 8-2, reactor (R5); 8-3, reactor (R6); 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 residual oil hydroprocessing method, 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] wherein the first hydroprocessing unit is provided with at least two reactors connected in parallel, at least one of the reactors connected in parallel is maintained in an online state, and at least one is maintained in an offline state; when the hydroprocessing catalyst in any reactor C maintained in an online state needs to be replaced, the reactor C is taken offline, and any reactor D maintained in an offline state is brought online to participate in the hydroprocessing reaction, and the catalyst of the reactor C is replaced to replace the reactor whose hydroprocessing catalyst needs to be replaced later; 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; and

[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 to truly achieve long-term operation of the residue oil hydrogenation system, on the one hand, it is necessary to solve the problem of metal deposition and deactivation of the hydrotreating catalyst in the protective reactor, and on the other hand, it is necessary to solve the problem of increased reactor pressure drop caused by carbon deposition in the reactor at the front of the main reaction.

[0031] The present invention provides a method for hydrotreating residual oil. In the method, a first hydrotreating unit is provided with at least two reactors connected in parallel, at least one of the reactors connected in parallel is maintained in an online state, and at least one is maintained in an offline state. When the hydrotreating catalyst of the online reactor needs to be replaced, the reactor can be taken offline, and the offline reactor can be brought online to replace the offline reactor to continue the hydrotreating catalytic reaction. At the same time, the hydrotreating catalyst of the offline reactor is replaced to replace the reactor whose hydrotreating catalyst needs to be replaced in the subsequent hydrotreating process. In this mode, replacing the hydrotreating catalyst does not affect the operating process of the residual oil hydrotreating, thereby solving the problem that the hydrotreating catalyst in the reactor cannot continue to operate due to metal deposition deactivation, resulting in the shutdown of the entire residual oil hydrotreating system.

[0032] In addition, the reactor feed end of the second hydroprocessing unit has a diversion structure. By diverting the materials in the reactors in the second hydroprocessing unit, the pressure drop of each reactor can be effectively controlled, solving the problem of the second hydroprocessing unit being unable to continue operating due to premature pressure drop caused by carbon deposition, etc.

[0033] In the present invention, according to a particularly preferred embodiment, the shutdown condition includes any one of the following conditions:

[0034] (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 ;

[0035] (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.

[0036] It should be noted that, in the present invention, the reactor of the first hydroprocessing unit can be switched online and offline and the catalyst can be replaced. 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 The pressure drop of the reactor of the third hydroprocessing unit almost does not exist and reaches the maximum pressure drop value P max Therefore, in practical applications of the present invention, the shutdown condition is usually set as the reaction temperature of any one of the second hydroprocessing unit and the third hydroprocessing unit reaching the maximum set temperature, thereby extending the hydroprocessing cycle.

[0037] It should also be noted that the hydrogenation conditions are conditions under which hydrogen is added.

[0038] According to a particularly preferred embodiment, under the condition that hydrogen is introduced 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 carry out a hydroprocessing reaction to obtain a hydroprocessed product. The present invention has no particular limitation on the flow rate and introduction method of the hydrogen, and operations known in the art can be used. The present invention will not be described in detail here, and those skilled in the art should not be construed as limiting the present invention.

[0039] It should be noted that, in the present invention, the maximum pressure drop value of the reactor is affected by factors such as the reactor material, manufacturing process, and the configuration of the reactor internal components, and the maximum pressure drop value of the reactor is provided by the reactor manufacturer. The method of the present invention is not particularly limited to this. For example, the maximum pressure drop value of the reactor in the embodiment of the present invention is 0.7 MPa.

[0040] Preferably, the pressure drop limit value P x Meet 0.6P max ≤P x <P max ; The maximum set temperature is 400℃~460℃.

[0041] 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 .

[0042] 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%.

[0043] 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:

[0044] 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.

[0045] Preferably, the active metal element is at least one element selected from nickel, cobalt, molybdenum and tungsten.

[0046] 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.

[0047] 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 m 2 / g, and the pore volume is 0.4~1.4mL / g.

[0048] In the present invention, the hydroprocessing catalyst is selected from at least one of a hydroprotection catalyst, a hydrodemetallization catalyst and a hydrodesulfurization catalyst.

[0049] 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.

[0050] 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.

[0051] 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, an average particle size of 3.0mm, and an average pore size of 25nm; the pore volume of the hydrodemetallization catalyst is 0.68mL / g, and the specific surface area is 165m2 / g, the average particle size is 1.3 mm, and the average pore size is 14 nm; the pore volume of the hydrodesulfurization catalyst is 0.60 mL / g, and the specific surface area is 180 m 2 / g, the average particle size is 1.0 mm, and the average pore size is 11 nm.

[0052] According to a particularly preferred embodiment, the first hydroprocessing unit is sequentially filled with a hydroprotection catalyst and a hydrodemetalization catalyst in the direction of the liquid phase flow, the second hydroprocessing unit is sequentially filled with the hydroprotection catalyst and the hydrodemetalization catalyst, and the third hydroprocessing unit is sequentially filled with the hydroprotection catalyst, the hydrodemetalization catalyst, and the hydrodesulfurization catalyst.

[0053] According to a particularly preferred embodiment, the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit each independently satisfy the following reaction conditions: the temperature is 300-460°C, the reaction pressure is 6-25 MPa, the hydrogen / oil volume ratio is 150-1500, and the total liquid hourly space velocity is 0.1-3 h -1 .

[0054] Preferably, the first hydroprocessing unit, the second hydroprocessing unit, and the third hydroprocessing unit each independently satisfy the following reaction conditions: the temperature is 350-420°C, the reaction pressure is 12-20 MPa; the hydrogen / oil volume ratio is 200-1000, and the total liquid hourly space velocity is 0.15-2 h -1 .

[0055] According to a particularly preferred embodiment, the second hydroprocessing unit is provided with 1 or at least 2 reactors connected in sequence. When at least 2 reactors are provided, the at least 2 reactors are connected in a manner that they are not only sequentially connected in series through a pipeline, but also connected in parallel at the feed end of each reactor through a shunt structure, so that the material can pass through all the reactors of the second hydroprocessing unit completely, and the flow rate into each reactor can be adjusted through the shunt structure to control the pressure drop of each reactor.

[0056] According to a particularly preferred embodiment, the third hydroprocessing unit is provided with at least 2 reactors connected in sequence, for example, as shown in Figure 1 , the third hydroprocessing unit is provided with 3 reactors connected in sequence: reactor (R4) 8-1, reactor (R5) 8-2, and reactor (R6) 8-3.

[0057] 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 countercurrent flow reactor.

[0058] According to a particularly preferred embodiment, the residue feedstock is selected from at least one of deasphalted oil, coking wax oil, catalytic light cycle oil, catalytic heavy cycle oil, coal liquefaction heavy oil, coal tar, atmospheric residue and vacuum residue.

[0059] According to a particularly preferred embodiment, the method further comprises: before introducing the residue feedstock into the first hydroprocessing unit, subjecting the residue feedstock to heat exchange treatment and / or preheating treatment.

[0060] The present application does not have special limitations on the specific mode of the heat exchange treatment and the preheating treatment, and known operations can be used. 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.

[0061] According to a particularly preferred embodiment, the method further comprises: subjecting the effluent after the hydroprocessing reaction of the third hydroprocessing unit to separation treatment to obtain the hydroprocessing product.

[0062] The present application does not have special limitations on the specific mode of the separation treatment, and known operations can be used. For example, fractionation treatment, etc. 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.

[0063] According to a particularly preferred embodiment, the residue hydroprocessing method provided by the present application is implemented by using a residue hydroprocessing system as shown in Figure 1 The process flow includes the following steps:

[0064] S1: under hydrogenation conditions, introducing a residue feedstock into a first hydrotreating unit, a second hydrotreating unit and a third hydrotreating unit connected in sequence through inlet 1 to perform a hydrotreating reaction, and obtaining a hydrotreated product; illustratively, the residue feedstock enters a residue hydrotreating system from inlet 1, enters reactor (R1) 3-1 through high-pressure valve (A) 2-1, and performs a hydrotreating reaction with the hydrotreating catalyst in reactor (R1) 3-1 to obtain first hydrotreating effluent 4, which enters reactor (R3) 6 in sequence through high-pressure valve (C) 2-3 and three-way valve 5, and performs a second hydrotreating reaction with the hydrotreating catalyst in reactor (R3) 6 to obtain second hydrotreating effluent 7, which enters reactor (R4) 8-1, reactor (R5) 8-2 and reactor (R6) 8-3 of the third hydrotreating unit in sequence through a pipeline, and performs a third hydrotreating reaction with the hydrotreating catalyst in each reactor, respectively, to obtain hydrotreated product 9. In this step, high-pressure valve (B) 2-2 and high-pressure valve (D) 2-4 are closed, reactor (R1) 3-1 remains online, and reactor (R2) 3-2 remains offline.

[0065] S2: when the hydrotreating catalyst in reactor (R1) 3-1 needs to be replaced, opening high-pressure valve (B) 2-2 and high-pressure valve (D) 2-4, closing high-pressure valve (A) 2-1 and high-pressure valve (C) 2-3, taking reactor (R1) 3-1 offline, taking reactor (R2) 3-2 online, and introducing the residue feedstock into reactor (R2) 3-2, reactor (R3) 6, reactor (R4) 8-1, reactor (R5) 8-2 and reactor (R6) 8-3 in sequence through high-pressure valve (B) 2-2 to perform a hydrotreating reaction, and obtaining hydrotreated product 9, and at the same time, replacing the hydrotreating catalyst in reactor (R1) 3-1, so that in the subsequent hydrotreating process, when the hydrotreating catalyst in reactor (R2) 3-2 needs to be replaced, reactor (R1) 3-1 can be taken online in time to replace reactor (R2) 3-2 to continue the hydrotreating reaction, thereby prolonging the hydrotreating cycle.

[0066] S3: when the pressure drop of reactor (R3) 6 reaches pressure drop limit value P x , dynamically adjusting the feed flow rate of reactor (R3) 6 to L A , and introducing the material from upstream of reactor (R3) 6 into reactor (R4) 8-1 adjacent downstream of reactor (R3) 6 at feed flow rate L B , so that the pressure drop of each reactor in the second hydrotreating unit and the third hydrotreating unit is less than maximum pressure drop value P max , wherein 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.

[0067] When the pressure drop of any reactor among reactor (R3) 6, reactor (R4) 8-1, reactor (R5) 8-2 and reactor (R6) 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.

[0068] A second aspect of the present invention provides a residual oil hydrogenation system, the system comprising:

[0069] 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;

[0070] The first hydroprocessing unit is provided with at least two reactors connected in parallel, and the feed end and the discharge end of each reactor are respectively provided with switches, so that each reactor can be independently put on or taken off line;

[0071] The feed end of any reactor A in the second hydroprocessing unit is provided with a split flow 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.

[0072] The residue oil hydrogenation system provided by the present invention has a first hydroprocessing unit provided with at least two reactors connected in parallel. In actual application, at least one of the parallel-connected reactors is maintained online, and at least one is maintained offline. The feed end and the discharge end of each reactor are respectively provided with switches, and the switches are used to quickly and easily realize the online and offline of each reactor. When the hydroprocessing catalyst of the online reactor needs to be replaced, the reactor can be taken offline, and the offline reactor can be put online to replace the offline reactor to continue the hydroprocessing catalytic reaction. At the same time, the hydroprocessing catalyst of the offline reactor is replaced to replace the reactor whose hydroprocessing catalyst needs to be replaced in the subsequent hydroprocessing process. In this mode, replacing the hydroprocessing catalyst does not affect the operation process of the residue oil hydroprocessing, and solves the problem that the hydroprocessing catalyst in the reactor cannot continue to operate due to metal deposition deactivation, causing the entire residue oil hydrogenation system to shut down.

[0073] In addition, the reactor feed end of the second hydroprocessing unit has a diversion structure. By diverting the materials in the reactors in the second hydroprocessing unit, the pressure drop of each reactor can be effectively controlled, solving the problem of the reactor of the second hydroprocessing unit being unable to continue operating due to premature pressure drop caused by carbon deposition, etc.

[0074] According to a particularly preferred embodiment, the switch is a high-pressure valve. It should be noted that the feed end described herein includes a feed port and an upstream pipeline, and the discharge end described herein includes a discharge port and a discharge pipeline. That is, in the first hydroprocessing unit, the switch at the feed end of each reactor can be located at the feed port of the reactor or at the upstream pipeline of the reactor. Similarly, the switch at the discharge end of the reactor can be located at the discharge port of the reactor or at the downstream pipeline of the reactor.

[0075] 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.

[0076] According to a particularly preferred embodiment, the second hydroprocessing unit is provided with one or at least two reactors connected in series. When at least two reactors are provided, the at least two reactors are connected in series via pipelines, and the feed ends of the reactors are connected in parallel via a diverter structure. This allows the material to pass completely through all reactors of the second hydroprocessing unit, and the diverter structure can adjust the flow rate entering each reactor to control the pressure drop of each reactor.

[0077] According to a particularly preferred embodiment, the third hydroprocessing unit is provided with at least two reactors connected in series, for example, Figure 1 As shown, the third hydroprocessing unit is provided with three reactors connected in series: reactor (R4) 8-1, reactor (R5) 8-2 and reactor (R6) 8-3.

[0078] 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 counterflow reactor.

[0079] According to a particularly preferred embodiment, the residue oil hydrogenation system provided by the present invention is as follows: Figure 1 As shown, it 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 1 of the hydrogenation system through a pipeline;

[0080] The first hydroprocessing unit is provided with two reactors connected in parallel with each other, such as Figure 1 The reactor (R1) 3-1 and the reactor (R2) 3-1 shown in FIG. 1 are each provided with a high-pressure valve at the feed end and the discharge end of each reactor, so that each reactor can be independently put on or taken off line. Figure 1 As shown, the feed end of the reactor (R1) 3-1 is provided with a high-pressure valve (A) 2-1, and the discharge end is provided with a high-pressure valve (C) 2-3; the feed end of the reactor (R2) 3-2 is provided with a high-pressure valve (B) 2-2, and the discharge end is provided with a high-pressure valve (D) 2-4.

[0081] The second hydroprocessing unit is provided with a reactor (R3) 6, and the feed end of the reactor (R3) 6 is provided with a diversion structure three-way valve 5, so that the feed flow rate L entering the reactor (R3) 6 can be adjusted online. A , so that the material from the upstream of the reactor (R3) 6 is fed at a feed rate L B Enter the reactor (R4) 8-1 adjacent to the downstream of the reactor (R3) 6.

[0082] 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.

[0083] In the following examples, the residual oil raw material is a mixture of atmospheric residue oil and vacuum residue oil, and its density at 20°C is 0.981 g / cm 3 , the residual carbon content is 12.6% by weight, the sulfur content is 4.02% by weight, and the metal (Ni+V) content is 100.6 μg / g.

[0084] In the following examples, the residual oil feedstock introduced into the residual oil hydroprocessing system has been preheated. In the following examples, the hydroprocessed product is obtained after passing through the residual oil hydroprocessing system and undergoing separation treatment.

[0085] In the following examples, each reactor is a downflow reactor, and the maximum pressure drop value of each reactor is 0.7 MPa.

[0086] 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.

[0087] In the following examples, the reaction pressure of the reaction zone is expressed in terms of hydrogen partial pressure.

[0088] In the following examples, along the direction of the liquid phase stream, the first hydroprocessing unit is sequentially packed with a hydroprotection catalyst and a hydrodemetallization catalyst, the second hydroprocessing unit is sequentially packed with the hydroprotection catalyst and the hydrodemetallization catalyst; the third hydroprocessing unit is sequentially packed with the hydroprotection catalyst, the hydrodemetallization catalyst and the hydrodesulfurization catalyst, and the types and specific compositions of the hydroprocessing catalysts are shown in Table 1, in which G represents a hydroprotection catalyst, M represents a hydrodemetallization catalyst, and S represents a hydrodesulfurization catalyst.

[0089] Table 1

[0090]

[0091]

[0092] Example 1

[0093] The residue hydroprocessing system provided in this example comprises 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 hydroprocessing system through a pipeline;

[0094] In the first hydroprocessing unit, two reactors are connected in parallel, and each reactor is provided with a switch at the feed end and the discharge end, so that each reactor can be independently put on line or taken off line.

[0095] The feed end of any reactor A in the second hydroprocessing unit is provided with a flow splitting structure, so that the feed flow L A into the reactor A can be adjusted online. B The material from upstream of the reactor A enters the downstream adjacent reactor B at a feed flow L

[0096] In this example, the first hydroprocessing unit is provided with two reactors R1 and R2 connected in parallel, and the feed end and the discharge end of each reactor R1 and reactor R2 are respectively provided with a high-pressure valve as a switch; the second hydroprocessing unit is provided with one reactor R3, and the feed end of the reactor R3 is provided with a three-way valve as a flow splitting structure; the third hydroprocessing unit is provided with two reactors R4 and R5 connected in series, and the hydroprocessing catalyst packing mode of each reactor and the initial reaction conditions of the reactor are shown in Table 2.

[0097] The residue hydroprocessing method provided in this example is implemented by using the residue hydroprocessing system provided in this example, and the specific process flow is as follows:

[0098] The residual oil feedstock and hydrogen were sequentially introduced into reactors R1, R3, R4, and R5 for hydrotreating reactions. 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 R3, R4, and R5 were simultaneously increased to control the sulfur content of the hydrotreated product to no more than 0.45 wt%.

[0099] Whenever the reaction temperature of reactor R1 reaches 410°C, reactor R1 is taken offline and the hydroprocessing catalyst in reactor R1 is replaced. At the same time, reactor R2 is brought online. Residual oil feedstock and hydrogen are sequentially introduced into reactors R2, R3, R4, and R5 for hydroprocessing reaction. Reactor R2 continues to operate according to the temperature increase standard of reactor R1. Reactors R1 and R2 are operated in rotation according to the above standards.

[0100] During the rotation operation of reactor R1 and reactor R2, whenever the pressure drop of reactor R3 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 R3 is reduced to below 0.3 MPa, the opening of the three-way valve at the feed end of the reactor R3 is adjusted and part of the upstream stream of the reactor R3 is directly introduced into the reactor R4.

[0101] At 27,300 hours of operation, the reaction temperature of reactors R3, R4 and R5 reached 410°C, and the residue oil hydrogenation system was shut down.

[0102] Example 2

[0103] The residue oil hydrogenation system, process flow and parameters of this embodiment are the same as those of Example 1, except that:

[0104] Whenever the pressure drop of reactor R3 reaches 0.56 MPa (i.e., 80% of the maximum pressure drop value of 0.7 MPa), the opening of the three-way valve at the feed end of reactor R3 is adjusted, and part of the logistics upstream of reactor R3 is introduced into reactor R4 to reduce the pressure drop of reactor R3 to below 0.4 MPa.

[0105] At 28100h, the reaction temperature of reactor R3, reactor R4 and reactor R5 reached 410℃, and the residue oil hydrogenation system was shut down.

[0106] Comparative Example 1

[0107] The residue oil hydroprocessing system of this comparative example includes four reactors connected in series, namely, reactor R1, reactor R3, reactor R4, and reactor R5. The loading method of the hydroprocessing catalyst and the initial reaction conditions of the reactors are shown in Table 2. The specific process flow is as follows:

[0108] The residual oil feedstock and hydrogen were introduced into reactors R1, R3, R4, and R5, 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, the reaction temperature of each reactor was increased synchronously during the operation of the system to control the sulfur content of the hydrotreated products to not exceed 0.45 wt%.

[0109] At 13,000 hours of operation, the pressure drop of reactor R1 reached 0.7 MPa and the residue oil hydrogenation system was shut down.

[0110] Comparative Example 2

[0111] The residue oil hydroprocessing system of this comparative example includes a first hydroprocessing unit and a second hydroprocessing unit connected in sequence. The first hydroprocessing unit is provided with two reactors in parallel, namely, reactor R1 and reactor R2. The second hydroprocessing unit is provided with three reactors connected in series, namely, reactor R3, reactor R4 and reactor R5. 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:

[0112] The residual oil feedstock and hydrogen were sequentially introduced into reactors R1, R3, R4, and R5 for hydrotreatment reactions. After 500 hours of operation, the properties of the hydrotreated products were shown in Table 3. Subsequently, during operation of the device, 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 R3, R4, and R5 were simultaneously increased to control the sulfur content of the hydrotreated products to no more than 0.45 wt%.

[0113] Whenever the reaction temperature of reactor R1 reaches 410°C, reactor R1 is taken offline and the hydrotreating catalyst in reactor R1 is replaced. At the same time, reactor R2 is put online, and the residual oil feedstock and hydrogen are introduced into reactor R2, reactor R3, reactor R4, and reactor R5 in sequence for hydrotreating reaction, and reactor R2 continues to operate according to the temperature increase standard of reactor R1; R1 and R2 are operated in rotation according to the above standards.

[0114] At 24,800 hours of operation, the pressure drop of reactor R3 reached 0.7 MPa and the residue oil hydrogenation system was shut down.

[0115] Table 2

[0116]

[0117] Table 3

[0118] project Residue oil raw materials Example 1 Example 2 Comparative Example 1 Comparative Example 2 Hydroprocessing products <![CDATA[密度(20℃),g / cm 3 ]]> 0.981 0.928 0.928 0.930 0.928 Carbon residue, weight % 12.6 4.8 4.8 5.0 4.8 Sulfur content, weight % 4.02 0.42 0.42 0.45 0.42 Metal (Ni+V) content, μg / g 100.6 10.2 10.2 11.8 10.2 System operation cycle / h - 27300 28100 13000 24800

[0119] From the above results, it can be seen that the provided residue hydroprocessing method and system have good residue hydroprocessing effect, the two reactors in parallel of the first hydroprocessing unit can be alternately put on line, so that the first hydroprocessing unit can continuously carry out hydroprocessing reaction, is not limited by the defect of saturated hydroprocessing catalyst metal deposition, and the processing cycle of the residue hydroprocessing system can be greatly prolonged; the reactors of the second hydroprocessing unit are provided with a flow splitting structure, under the condition of effectively controlling the pressure drop, all the reactors have material passing through, and the role of each reactor is maximally played.

[0120] The present application overcomes the short running cycle defect of the existing residue hydrogenation system, has the advantages of high reactor utilization rate, simple operation and long running cycle.

[0121] The above describes the preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application, and all belong to the protection scope of the present application.

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; wherein the first hydroprocessing unit is provided with at least two reactors connected in parallel, at least one of the reactors connected in parallel is maintained in an online state, and at least one is maintained in an offline state; when the hydroprocessing catalyst in any reactor C maintained in an online state needs to be replaced, the reactor C is taken offline, and any reactor D maintained in an offline state is brought online to participate in the hydroprocessing reaction, and the catalyst of the reactor C is replaced to replace the reactor whose hydroprocessing catalyst needs to be replaced later; the second hydroprocessing unit is provided with one or at least two reactors connected in sequence; the third hydroprocessing unit is provided with at least two reactors connected in sequence; 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; and 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 all the hydroprocessing catalysts in 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 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.

14. 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.

15. 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.

16. 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.

17. 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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