Residue oil hydrogenation method

Abstract

The present invention discloses a method for hydrogenating residual oil. The method comprises at least one upflow hydrogenation reactor and one trickle bed hydrogenation reactor. A screen is installed within the upflow hydrogenation reactor at a height of 100 to 500 mm above the catalyst loading surface. The screen is made of a material with a melting point of 370 to 410°C. The method comprises: sequentially passing the residual oil feedstock and hydrogen through the upflow hydrogenation reactor and the trickle bed hydrogenation reactor to obtain a residual oil hydrogenation product. This method can solve the problems of catalyst carryover caused by initial fluctuations in the device and screen clogging and coking in the middle and late stages, without affecting the hydrogenation reaction or device operation.

Description

Technical Field

[0001] The present invention relates to a residue oil hydrogenation method, in particular to a residue oil hydrogenation method using an upflow-trickle bed combined process. Background Art

[0002] The heavy and inferior quality of oil resources is becoming increasingly serious, and environmental protection regulations are constantly being upgraded, forcing the development of the petrochemical industry to take the path of deep processing of heavy oil and cleaner products.

[0003] Among the many heavy oil processing technologies, trickle-bed residue hydrotreating technology is adopted by most refineries due to its low cost, simple operation, and mature process. However, the high pressure drop in the front reactor of the trickle-bed process often restricts the unit's operating cycle at the end of its operation. To address this issue, some technicians have proposed using an upflow-trickle-bed combined hydrogenation process technology. The upflow reactor serves as a pre-treatment reactor, with the reactants flowing from bottom to top. By utilizing the technical characteristics of its catalyst bed with slight expansion and low pressure drop, this technology alleviates the problem of conventional trickle-bed reactors being forced to shut down due to high pressure drop at the end of their operation when processing low-quality raw materials.

[0004] However, the gas phase of the upflow reactor flows from bottom to top. In order to ensure the depth of hydrogenation, a high hydrogen-to-oil volume ratio is required. The high gas velocity can easily cause tiny catalyst particles to be carried out of the reactor. The high-activity catalyst of the upflow reactor enters the rear trickle bed reactor, which will cause reaction disorder. In addition, especially in the early stage of the operation of the device, it is easy for the catalyst to be carried out due to fluctuations in process operating parameters such as logistics linear velocity and feed properties. In response to this problem, technicians proposed a solution of installing a screen on the top of the catalyst in the upflow reactor to intercept catalyst particles and prevent them from entering the rear reactor. However, in the middle of the operation of the device, the screen was blocked by coke, causing the pressure drop in the reactor to increase rapidly, and the operation was severely restricted.

[0005] CN1315994C discloses an upflow reactor system employing at least two catalyst layers with different hydrogenation activities, wherein the catalyst in the lower horizontal catalyst layer has a lower hydrogenation activity than the catalyst in the upper horizontal catalyst layer. This upflow reactor employs a conventional catalyst loading method, whereby catalyst activity gradually increases along the flow direction, leading to a gradual increase in hydrogen consumption and heat release in the high-activity catalyst bed. However, due to the limited hydrogen-to-oil ratio, the upflow reactor is susceptible to localized hydrogen deficiency and bed disturbances, which can affect catalyst performance and the stable operation of the device.

[0006] CN209923263U discloses a bottom-feed hydrogenation reactor, which has a feed port at the bottom and a discharge port at the top. The bottom-feed hydrogenation reactor includes: a catalyst bed, which is arranged in the bottom-feed hydrogenation reactor; a first metal wire mesh, which is arranged above the catalyst bed, and the aperture of the first metal wire mesh is 30% to 70% of the particle size of the catalyst in the catalyst bed; an upper inert filler layer, which is arranged above the first metal wire mesh; a gland grid, which is arranged above the upper inert filler layer; a lower inert filler layer, which is arranged below the catalyst bed; and a load-bearing grid, which is arranged below the lower inert filler layer, and the aperture of the load-bearing grid is smaller than the particle size of the lower inert filler layer. This hydrogenation reactor still has the risk of coking and clogging of the metal mesh and / or grid.

[0007] CN111375348B discloses a trickle bed flow reactor and its applications. The reactor comprises a reactor shell, within which a support grid, a lower catalyst bed, a sliding grid layer, an upper catalyst bed, and a gland grid are arranged along the material flow direction. A reaction material inlet is provided at the bottom of the reactor shell, and a reaction material outlet is provided at the top of the reactor shell. The sliding grid layer comprises an upper sliding grid and a lower sliding grid. The reactor may also be provided with a catalyst dust filter layer and a gland. The fixed bed flow reactor can effectively control the expansion and contraction of the catalyst bed, preventing particle abrasion caused by the catalyst during floating, protecting the catalyst while reducing dust generation. However, this method does not address the problem of grid clogging. Summary of the Invention

[0008] In response to the shortcomings of the prior art, the present invention provides a residual oil hydrogenation method that can solve the problems of catalyst carryover caused by initial fluctuations in the device and blockage and coking of screens in the middle and late stages, without affecting the hydrogenation reaction and device operation.

[0009] The present invention provides a residue oil hydrogenation method, comprising at least one upflow hydrogenation reactor and one trickle bed hydrogenation reactor, wherein a screen is provided inside the upflow hydrogenation reactor at a position 100 to 500 mm above a catalyst feeding surface, and the screen is made of a material with a melting point of 370 to 410° C. The method comprises: a residue oil feedstock and hydrogen gas sequentially pass through the upflow hydrogenation reactor and the trickle bed hydrogenation reactor to obtain a residue oil hydrogenation product.

[0010] In the method of the present invention, the barrier net is made of a material with a melting point of 375-410° C., preferably a material with a melting point of 375-405° C., and the material is preferably a tin-based alloy.

[0011] In the method of the present invention, the thickness of the screen is 5 to 30 mm, preferably 5 to 15 mm, the side length of the unit grid is 1 to 5 mm, preferably 1 to 2 mm, and the porosity is 85% to 95%, preferably 85% to 90%. The shape of the unit grid can be rectangular, trapezoidal, triangular, etc., preferably an inverted trapezoidal structure. The unit grid size of the screen is required to prevent the catalyst particles loaded in the upflow hydrogenation reactor from passing through. The size of the screen matches the inner diameter of the upflow hydrogenation reactor. The method of fixing the screen in the reactor can be bolt connection, welding, riveting and inorganic bonding chemical fixation, etc., and welding is preferred.

[0012] In the method of the present invention, the barrier is preferably formed of a triangular unit grid, including horizontal bars, vertical bars and diagonal bars, all of which are made of tin-based alloys. The diagonal bars, vertical bars and horizontal bars are made of rods with different melting points, preferably increasing in order of the melting points of the diagonal bars, vertical bars and horizontal bars, which are 375-385°C, 385-395°C and 395-405°C, respectively. Furthermore, the diagonal bars are at least 5°C lower than the vertical bars, and the vertical bars are at least 5°C lower than the horizontal bars. The barrier is made of the material with the highest melting point on all sides. Preferably, the barrier is fixed to a height of 200-300 mm above the catalyst loading surface.

[0013] In the method of the present invention, the screen is preferably a multi-layer screen, more preferably 2-4 layers, wherein each layer of screen is preferably made of a single melting point material, preferably, the melting point difference between two adjacent layers of screen is at least 5°C, further 5-10°C. Furthermore, the multi-layer screen with increasing melting point along the logistics direction is preferably a three-layer screen, and the melting points along the logistics direction are 375-385°C, 385-395°C, and 395-405°C, respectively. Furthermore, the lowest screen is 200-300 mm above the catalyst loading surface, and the distance between two adjacent screens is 50-200 mm, preferably 50-150 mm.

[0014] In the method of the present invention, an upflow hydrogenation reactor and multiple trickle-bed hydrogenation reactors are employed, wherein the number of the multiple trickle-bed hydrogenation reactors may be 2-4. A scale basket is disposed on the top of the trickle-bed hydrogenation reactor adjacent to the upflow hydrogenation reactor. The scale basket may be filled with a filler selected from at least one of conventional porcelain balls, ceramic foam, and a catalyst, with a toothed ball catalyst being preferred.

[0015] In the method of the present invention, the catalyst vulcanization is carried out under conditions below the melting point of the barrier, for example, the catalyst vulcanization temperature is 160-360° C., and wet vulcanization is preferred.

[0016] In the method of the present invention, the residual oil feedstock is vacuum residue oil, and a diluent oil may be added, wherein the diluent oil primarily comprises at least one of straight-run wax oil, coker wax oil, catalytically cracked diesel, and catalytically cracked slurry oil. Furthermore, the vacuum residue oil accounts for more than 30% of the residual oil feedstock by mass, generally 30% to 80%.

[0017] In the method of the present invention, the impurity contents in the residual oil raw material, calculated by mass fraction, are as follows: sulfur is 0.80% to 5.00%, residual carbon value is 6% to 20%, nitrogen is 0.15% to 0.50%, and metal (nickel + vanadium) is 40 to 200 mg / kg.

[0018] In the method of the present invention, the reaction conditions of the upflow hydrogenation reactor are as follows: the initial temperature of the reactor outlet is 365°C to 385°C, preferably the initial temperature of the reactor outlet is lower than the melting point of the screen, the final temperature of the reactor outlet is 395°C to 410°C, preferably the final temperature of the reactor outlet is higher than the melting point of the screen; the reaction pressure is 14 to 17 MPa, preferably 16 to 17 MPa; the hydrogen-to-oil volume ratio is 210 to 260 Nm 3 / m 3 , preferably 240~260Nm 3 / m 3 , liquid hourly volumetric space velocity is 0.69~1.03h -1 , preferably 0.80~0.90h -1 .

[0019] In the method of the present invention, the hydrogenation catalyst used in the upflow hydrogenation reactor is a commonly used hydrogenation catalyst in upflow residue hydrotreating reactors. It generally primarily performs hydrodemetallization, and also has certain hydrodesulfurization and hydrorecoal removal functions. The hydrogenation catalyst generally comprises a support component and a hydrogenation-active metal component, wherein the hydrogenation-active metal component comprises a Group VIB metal element and / or a Group VIII metal element, wherein the Group VIB metal element is preferably Mo, and the Group VIII metal element is preferably Ni and / or Co. The Group VIB metal content, calculated as oxide, is 7.0% to 16.0%, preferably 8.0% to 15.0%, and the Group VIII metal content, calculated as oxide, is 2.0% to 7.0%, preferably 2.0% to 5.0%, based on the weight of the catalyst. The support component is generally an alumina-based support. The hydrogenation catalyst may further comprise conventional additive components, such as at least one of phosphorus, boron, and silicon. The catalyst may be in the shape of a toothed ball, a four-impeller, a sphere, etc. For example, the FZC series commercial catalysts developed by Sinopec Fushun Petrochemical Research Institute or Dalian Petrochemical Research Institute may be used, such as FZC-1MN, FZC-2MN, FZC-3MN, FZC-12B-6, FZC-100B, etc.

[0020] In the method of the present invention, the reaction conditions of the trickle bed hydrogenation reactor are as follows: the inlet temperature of the trickle bed is 360-375°C, preferably the inlet temperature of the trickle bed is lower than the melting point of the barrier, and the hydrogen-to-oil volume ratio of the trickle bed is 500-800 Nm 3 / m 3 , preferably 600~800Nm 3 / m 3 The reaction pressure is 14-17 MPa, preferably 16-17 MPa, and the liquid hourly volume space velocity is 0.18-28 h -1 , preferably 0.22~24h -1 The inlet temperature of the trickle bed hydrogenation reactor is lower than the melting point of the screen, and can be cooled by cold hydrogen. The cold hydrogen is injected close to the inlet of the trickle bed reactor. In addition, the cold hydrogen can also serve as a supplementary hydrogen to meet the hydrogen-to-oil volume ratio at the inlet of the trickle bed. In this way, in the later stage of the device operation, after the screen melts, the molten screen material can be precipitated at the top of the trickle bed hydrogenation reactor and intercepted by the scale basket.

[0021] In the method of the present invention, the hydrogenation catalyst used in the trickle-bed hydrogenation reactor is a conventional fixed-bed residue hydrotreating catalyst. The residue hydrotreating catalyst used is a catalyst having at least one of the following functions: residue hydrodemetallization, hydrodesulfurization, and hydrodenitrogenation. Residue hydrotreating catalysts generally use a porous refractory inorganic oxide such as alumina as a carrier, a Group VIB and / or Group VIII metal (such as at least one oxide of W, Mo, Co, Ni, etc.) as an active component, and optionally contain various other additives such as at least one of P, Si, F, and B.

[0022] In the method of the present invention, the residue oil hydrotreating catalyst used in the trickle bed hydrotreating reactor includes a residue oil hydroprotection catalyst, a residue oil hydrodemetallization catalyst, and a residue oil hydrodesulfurization catalyst. Based on the total loading volume of the trickle bed residue oil hydrotreating catalyst, the residue oil hydroprotection catalyst accounts for 3% to 25%, preferably 15% to 20% of the total loading volume; the residue oil hydrodemetallization catalyst accounts for 20% to 60%, preferably 20% to 50% of the total loading volume; and the residue oil hydrodesulfurization catalyst accounts for 10% to 50%, preferably 20% to 40% of the total loading volume. After the hydrodesulfurization catalyst, residue oil hydrodenitrogenation and carbon residue conversion catalysts may be optionally loaded, with their loading volume accounting for no more than 28% of the total loading volume. Residue hydrotreating catalysts can be loaded in a conventional gradation order, generally contacting the feedstock with a residue hydrotreating protection catalyst, a residue hydrodemetallization catalyst, a residue hydrodesulfurization catalyst, and a residue hydrodenitrogenation / carbon residue conversion catalyst in sequence. Of course, there are also techniques for loading a mixture of two or more of these catalysts. The residue hydrotreating protection catalyst, the residue hydrodemetallization catalyst, the residue hydrodesulfurization catalyst, the residue hydrodenitrogenation / carbon residue conversion catalyst can be catalysts commonly used in the art with corresponding functions, such as the CEN, FZC, ZTN, and ZTS series residue hydrotreating catalysts produced by the Catalyst Branch of Sinopec.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. The method of the present invention simultaneously solves the problem of catalyst being carried out due to fluctuations in the initial stage of the device and the blockage and coking of the screen in the middle and late stages. The inventors have found through research that a screen made of a material with a melting point of 370-410°C is installed on the upper part of the upflow hydrogenation reactor. In the early stage of the device operation, the catalyst can be effectively intercepted to prevent the catalyst inside the upflow reactor from running away due to fluctuations in the process conditions of the device and entering the rear reactor. In the middle and late stages of the device operation, the screen gradually melts due to the increase in the temperature of the reactor, solving the problem of pressure drop caused by blockage of the screen due to coking. Moreover, the screen gradually melts and flows out with the liquid phase, and is intercepted by the scale basket after precipitation at the top of the trickle bed. This method is not only simple and easy to implement, but also can greatly extend the operating cycle life of the device.

[0025] 2. In the method of the present invention, the screen has no effect on the operation and reaction of the device during and after the melting process. The screen is preferably made of rods with three specific melting points or composed of three layers of screens with specific melting points. The screen disappears slowly, which is conducive to the stable operation of the device. After the screen is melted, it flows out with the liquid phase and enters the inlet of the trickle bed hydrogenation reactor by utilizing the logistics to inject cold hydrogen for cooling. The melted screen will precipitate at the top of the trickle bed hydrogenation reactor and be intercepted by the scale basket.

[0026] 3. The method of the present invention is simple to manufacture and low in cost. The materials required for the preparation of the barrier are widely available and inexpensive, and can be obtained by simple means such as punching dies. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the internal structure and process of the device used in the method of the present invention;

[0028] Figure 2 The present invention adopts the main structure of single-layer barrier design;

[0029] The following are the descriptions of the reference numerals:

[0030] Upflow reactor inlet 1; upflow reactor 2; upflow catalyst 3; screen 4; upflow reactor outlet 5; cold hydrogen 6; fouling basket 7; trickle bed first reactor 8; trickle bed second reactor 9; trickle bed third reactor 10; trickle bed fourth reactor 11; hydrogenation product 12. DETAILED DESCRIPTION

[0031] The following is a further description of the modification method provided by the present invention and its functions and effects with reference to the accompanying drawings and examples, but the present invention is not limited thereto. Many devices, such as pumps, heat exchangers, and heating furnaces, are omitted from the drawings, but are well known to those skilled in the art.

[0032] The method of the present invention is as follows Figure 1 As shown, taking an upflow reactor and three trickle bed reactors as an example, three layers of screens 4 are set above the catalyst 3 feeding surface inside the upflow reactor 1, wherein the first screen is made of material C, the second screen is made of material B, and the third screen is made of material A. A scale basket 7 is set on the top of the first trickle bed reactor 8. The process is as follows: hydrogen and residual oil feedstock are mixed and enter the upflow reactor 2 through the upflow reactor inlet 1, contact with the upflow catalyst 3 for hydrogenation reaction, and then pass through the screen 4. The resulting reaction product is discharged from the outlet 5 of the upflow reactor 2; the reaction product enters the first trickle bed reactor 8, and the inlet temperature of the first trickle bed reactor is controlled to be lower than the melting point of the screen by injecting cold hydrogen 6. After passing through the scale basket 7, it contacts the catalyst for hydrogenation reaction, and then passes through the second trickle bed reactor 9, the third trickle bed reactor 10 and the fourth trickle bed reactor 11 in sequence to react to obtain a hydrogenated product 12.

[0033] The main structure of the single-layer barrier design adopted by the present invention is as follows Figure 2 As shown, the unit grid is triangular in shape and includes horizontal bars, vertical bars and diagonal bars. The horizontal bars are made of material A, the vertical bars are made of material B and the diagonal bars are made of material C. The melting points of materials A, B and C decrease in sequence. The surrounding areas of the barrier are made of material A with the highest melting point.

[0034] The separator material used in the embodiments and comparative examples of the present invention is tin-based alloy.

[0035] The reactors of the examples and comparative examples of the present invention all used the same test apparatus, with the pressure drop limit of the apparatus being 1.2 MPa. The upflow reactor had a height of 1300 mm and a diameter of 560 mm.

[0036] The catalysts of the embodiments and comparative examples of the present invention all adopt FZC series catalysts. The grading scheme is shown in Table 2. The catalyst FZC-1MN and properties of the upflow reactor catalyst are shown in Table 1. The catalyst filled in the fouler is FZC-1MN, which is not counted in the catalyst grading scheme.

[0037] Table 1 Main physicochemical properties of upflow catalyst

[0038]

[0039]

[0040] Table 2 Catalyst grading scheme

[0041]

[0042] The difference between the embodiment of the present invention and the comparative example is that the main properties of the processed raw oil are shown in Table 3, and the main operating conditions are shown in Table 4.

[0043] Table 3 Main properties of processed raw oil

[0044] project Numerical <![CDATA[Density (20 °C) / (g / cm 3 )]]> 0.989 <![CDATA[Viscosity (80 °C) / (mm 2 / s)]]> 662 Residual carbon value / % 12.49 Sulfur mass fraction / % 4.21 Nitrogen mass fraction / (mg / kg) 3478 Hydrogen mass fraction / % 10.99 Metal (nickel) mass fraction / % 24.17 Metal (vanadium) mass fraction / % 72.13

[0045] Table 4 Main operating conditions of the device

[0046]

[0047]

[0048] During the start-up phase of the embodiments and comparative examples of the present invention, the properties of the start-up medium oil are shown in Table 5. After the catalyst is loaded and the airtightness is checked, hydrogen is introduced, the control system pressure is 16 MPa, and start-up diesel is introduced from the first reactor into the reaction system to wet the catalyst. The waste oil is then discarded to clean the catalyst. After the discarding is completed, the reactor temperature is controlled to 200°C, and the start-up wax oil is introduced to replace the diesel oil to establish a wax oil full circulation process. The catalyst vulcanization process is started: the vulcanizing agent is injected, and the temperature of the heating furnace outlet is raised to 230°C at a rate of 5°C / h. When the reaction temperature reaches 230°C, the temperature is stopped and hydrogen sulfide penetration is allowed. After hydrogen sulfide penetration and the hydrogen sulfide concentration in the circulating hydrogen is 0.2-1.0 vol.%, the first constant temperature vulcanization is carried out for 4 hours. The reactor temperature was then raised at a rate of 10°C / h to 280°C. At 280°C, a second constant-temperature sulfidation process was conducted for four hours, during which the hydrogen sulfide content in the circulating hydrogen was controlled at 1.0-1.5 vol.%. The reactor temperature was then raised at a rate of 5°C / h to 310°C. After reaching 310°C, the temperature was maintained at that temperature for four hours before the sulfidation process was completed. During this period, the hydrogen sulfide content in the circulating hydrogen was controlled at 1.5-2.0 vol.% by adjusting the sulfiding agent injection rate. To resume operation after an unplanned shutdown, the above procedure was repeated, but without the sulfiding agent injection.

[0049] Table 5 Main properties of the start-up medium oil

[0050] project Start diesel Start wax oil Sulfur mass content / wt.% 1.2 3.0 Nitrogen mass content / (mg / kg) 50 700 Distillation range / ℃ ASTM D-86 ASTM D-1160 Initial distillation point 210 382 Final distillation point 356 534

[0051] During the shutdown phase, the reactor temperature was reduced to 310°C at a rate of 5°C / h, and the processing raw materials were replaced with start-up wax oil. The reactor temperature was reduced to 200°C at a rate of 10°C / h, and the start-up wax oil was replaced with start-up diesel, and then nitrogen was introduced to replace the hydrogen.

[0052] The operation stage is mainly to control the reaction temperature. As the reaction proceeds, the catalyst gradually deactivates. By increasing the reaction temperature to compensate for the catalyst activity and make the product properties meet the standards, the outlet temperature of the upflow reactor will gradually increase.

[0053] Example 1

[0054] Use Figure 1 structure and processes.

[0055] First, three screens were prepared using tin-based alloy materials with melting points of 380, 390, and 400°C, respectively. They were installed from bottom to top with a spacing of 50 mm between them. The three screens had the same specifications, with a thickness of 10 mm, a unit grid side length of 1 mm, and a porosity of 90%. The first screen was fixed 200 mm above the upflow catalyst material surface. A fouling basket was installed on the top of the first trickle bed reactor, i.e., above the distribution plate. The internal filler of the fouling basket was a toothed ball-type hydrogenation catalyst FZC-1MN.

[0056] The unit then went through startup, reaction operation, and shutdown phases. The entire cycle operated smoothly, with stable hydrogenation results. The main operating parameters of the test unit are shown in Table 6. After the shutdown, an inspection of the top fouling basket of the first trickle-bed reactor revealed irregular metallic solids attached to the exterior, but no toothed ball-shaped upflow catalyst particles were found.

[0057] Example 2

[0058] Use Figure 1 The process and installation of the upflow reactor Figure 2 Single layer blocking.

[0059] First, tin-based alloy materials with melting points of 378, 389, and 395°C are used as the diagonal, vertical, and horizontal bars of the barrier respectively. The surrounding areas are made of tin-based alloy materials with a temperature of 395°C, and are combined into a single barrier with multiple melting point rods. The barrier has a thickness of 15 mm, a unit grid side length of 2 mm, and a porosity of 87%. The barrier is fixed 300 mm above the upflow catalyst feeding surface, and a fouling basket is installed on the top of the first trickle bed reactor, i.e., the upper part of the distribution plate. The internal filler of the fouling basket is porcelain balls.

[0060] The unit then underwent startup, reaction operation, and shutdown. The entire cycle operated smoothly, with stable hydrogenation results. The main operating parameters of the test unit are shown in Table 6. After the shutdown, an inspection of the top fouling basket of the first trickle-bed reactor revealed irregular metallic solids attached to the exterior, but no toothed ball-shaped upflow catalyst particles were found.

[0061] Comparative Example 1

[0062] Use Figure 1 process.

[0063] The main difference from Example 2 is that: first, a screen with a thickness of 15 mm, a unit grid side length of 2 mm, and a porosity of 90% is prepared using austenitic stainless steel material (305 stainless steel) with a melting point exceeding 1300°C. The screen is fixed to 300 mm above the upflow catalyst material surface, and a scale basket is installed on the top of the first trickle bed reactor, i.e., above the distribution plate. The inside of the scale basket is filled with porcelain balls.

[0064] Subsequently, the device was started up and the reaction operation began. In the middle of the reaction, the pressure drop of the upflow reactor increased rapidly to 0.80 MPa. In order to find the cause, the device was shut down. After the shutdown, it was found that the screen of the upflow reactor was seriously coked. After the screen was removed, the device was restarted and restored to the process conditions before the shutdown. The pressure drop of the upflow reactor became 0.46 MPa. The main operating parameters of the test device are shown in Table 6.

[0065] Comparative Example 2

[0066] Use Figure 1process.

[0067] The main difference from Example 2 is that: first, austenitic stainless steel material (305 stainless steel) with a melting point exceeding 1300°C is used to prepare a barrier with a thickness of 15 mm, a unit grid side length of 2 mm, and a porosity of 90%. The barrier is fixed to 300 mm above the upflow catalyst feeding surface, and no scale basket is installed on the top of the first trickle bed reactor.

[0068] The properties of the processed raw oil are shown in Table 1, the properties of the catalyst used are shown in Table 2, and the main operating conditions are shown in Table 3.

[0069] The unit then underwent startup and initial reaction operation. In the middle and late stages of the reaction, the pressure drop in the upflow reactor rapidly increased to 1.16 MPa, then plummeted to 0.65 MPa. The pressure drop in the first trickle-bed reactor rapidly increased from 0.15 MPa to 0.38 MPa, and the properties of the hydrogenated tail oil deteriorated. After the forced shutdown, inspection revealed severe coking and mechanical deformation of the screen in the upflow reactor, as well as severe compaction of the catalyst bed top in the first trickle-bed reactor. The main operating parameters of the test unit are shown in Table 6.

[0070] Table 6 Main operating parameters of the test device

[0071]

[0072]

[0073] ① After the screen is removed, the pressure drop of the upflow reactor is restored to the process conditions before shutdown;

[0074] ② When the pressure drop of the upflow reactor rises to 1.16MPa, the pressure drop of the reactor drops sharply to 0.65MPa.

Claims

1. A method for hydrogenating residual oil, comprising using an upflow hydrogenation reactor and a plurality of trickle bed hydrogenation reactors, wherein: A screen is provided inside the upflow hydrogenation reactor at a position 100 to 500 mm above the catalyst feeding surface, and the screen is made of a material with a melting point of 370 to 410° C. The method comprises: residual oil feedstock and hydrogen are sequentially passed through the upflow hydrogenation reactor and the trickle bed hydrogenation reactor to obtain a residual oil hydrogenation product; the size of the screen matches the inner diameter of the upflow hydrogenation reactor, and the unit grid size of the screen is required to be unable to allow the catalyst particles loaded in the upflow hydrogenation reactor to pass through; the screen is multi-layered, and the melting point of the screen increases successively along the logistics direction; a scale basket is provided on the top of the trickle bed hydrogenation reactor adjacent to the upflow hydrogenation reactor, and the scale basket is filled with a filler selected from at least one of porcelain balls, foam ceramics and catalysts; the initial temperature of the outlet of the upflow hydrogenation reactor is lower than the melting point of the screen, and the final temperature of the outlet of the upflow hydrogenation reactor is higher than the melting point of the screen; and the inlet temperature of the trickle bed hydrogenation reactor is lower than the melting point of the screen.

2. The method according to claim 1, characterized in that The barrier is made of a material with a melting point of 375~405℃.

3. The method according to claim 2, characterized in that The blocking material is tin-based alloy.

4. The method according to claim 1, characterized in that The thickness of the barrier is 5~30mm, the side length of the unit grid in the barrier is 1~5mm, and the porosity is 85%~95%.

5. The method according to claim 4, characterized in that The thickness of the barrier is 5~15mm, the side length of the unit grid in the barrier is 1~2mm, and the porosity is 85%~90%.

6. The method according to claim 1, characterized in that The barrier net adopts a triangular unit grid shape, including horizontal bars, vertical bars and diagonal bars, and the materials are all tin-based alloys. Among them, the diagonal bars, vertical bars and horizontal bars are rods with different melting points, and the melting points of the diagonal bars, vertical bars and horizontal bars increase in sequence, which are 375~385℃, 385~395℃ and 395~405℃ respectively. The diagonal bars are at least 5℃ lower than the vertical bars, and the vertical bars are at least 5℃ lower than the horizontal bars. The barrier net is made of materials with the highest melting point on all sides.

7. The method according to claim 6, characterized in that The screen is fixed to a position 200-300 mm above the catalyst loading surface.

8. The method according to claim 1, characterized in that The blocking net adopts 2-4 layers.

9. The method according to claim 1, characterized in that Each layer of the barrier is made of material with a single melting point.

10. The method according to claim 1, characterized in that The melting point difference between two adjacent layers of screens should be at least 5°C.

11. The method according to claim 1, characterized in that The melting point difference between two adjacent layers of screens is 5~10℃.

12. The method according to claim 1, characterized in that The multi-layer screen consists of three layers of screen, and their melting points along the logistics direction are 375~385℃, 385~395℃, and 395~405℃ respectively.

13. The method according to claim 1, characterized in that The lowest screen is 200~300mm away from the catalyst loading surface, and the distance between two adjacent screens is 50~200mm.

14. The method according to claim 13, characterized in that The distance between two adjacent layers of blocking nets is 50~150mm.

15. The method according to claim 1, characterized in that 2-4 multiple trickle bed hydrogenation reactors are used.

16. The method according to claim 1, characterized in that The filler filled inside the fouling basket is a tooth ball type catalyst.

17. The method according to claim 1, characterized in that The catalyst sulfidation is carried out under the condition of being lower than the melting point of the screen.

18. The method according to claim 17, characterized in that The catalyst is sulfurized by wet sulfurization.

19. The method according to claim 1, characterized in that The residual oil raw material is vacuum residual oil; the impurity content of the residual oil raw material, calculated by mass fraction, is as follows: sulfur is 0.80% to 5.00%, residual carbon value is 6% to 20%, nitrogen is 0.15% to 0.50%, and metals, calculated as nickel and vanadium, are 40 to 200 mg / kg.

20. The method according to claim 19, characterized in that A diluent oil is added to the residual oil raw material, wherein the diluent oil includes at least one of straight-run wax oil, coker wax oil, catalytic cracking diesel oil, and catalytic cracking slurry oil.

21. The method according to claim 1, characterized in that The reaction conditions of the upflow hydrogenation reactor are as follows: the initial temperature of the reactor outlet is 365°C to 385°C, the final temperature of the reactor outlet is 395°C to 410°C; the reaction pressure is 14-17 MPa; the hydrogen-to-oil volume ratio is 210-260 Nm³ / m³, and the liquid hourly space velocity is 0.69-1.03 h -1 .

22. The method according to claim 21, characterized in that The reaction conditions of the upflow hydrogenation reactor are as follows: reaction pressure of 16-17 MPa; hydrogen-to-oil volume ratio of 240-260 Nm³ / m³; liquid hourly volume space velocity of 0.80-0.90 h -1 .

23. The method according to claim 1, characterized in that The reaction conditions of the trickle bed hydrogenation reactor are as follows: the inlet temperature of the trickle bed is 360-375°C, the hydrogen-to-oil volume ratio of the trickle bed inlet is 500-800 Nm³ / m³, the reaction pressure is 14-17 MPa, and the liquid hourly volume space velocity is 0.18-28 h -1 .

24. The method according to claim 23, characterized in that The reaction conditions of the trickle bed hydrogenation reactor are as follows: the hydrogen-to-oil volume ratio at the first inlet of the trickle bed is 600-800 Nm³ / m³, the reaction pressure is 16-17 MPa, and the liquid hourly volume space velocity is 0.22-24 h -1 .

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