A method for processing inferior heavy oil

Abstract

The application discloses a method for hydrogenation of inferior heavy oil, which comprises the following steps: (1) in the presence of hydrogen, a residual oil raw material enters a first hydrogenation reaction zone to perform hydrogenation reaction; (2) in the presence of hydrogen, a reaction effluent of the first hydrogenation reaction zone obtained in the step (1) enters a second hydrogenation reaction zone to perform hydrogenation reaction, at least one upflow reactor is arranged in the second hydrogenation reaction zone, and a reaction product is subjected to gas-liquid separation and fractionation to obtain a gas product and naphtha, diesel oil and hydrogenated residual oil fractions. The method can overcome the problem that the operation cycle of a device is shortened after some inferior residual oil is mixed in the existing fixed-bed residual oil hydrogenation method, and can improve the carbon residue removal efficiency of the fixed-bed hydrogenation device and the quality of the feed of a downstream catalytic cracking device.

Description

Technical Field

[0001] This invention belongs to the field of oil refining and chemical technology, and relates to a method for hydrogenating inferior heavy oil, particularly a fixed-bed hydrogenation method for inferior heavy oil with long-term stable operation. Background Technology

[0002] With the increasing trend of crude oil becoming lower quality and heavier, the efficient utilization of residue oil, which accounts for 40-60 wt% of crude oil, has become a core factor directly affecting refinery profitability. Residue oil hydrotreating processes offer high light oil yields, can produce low-sulfur fuel oil, or provide feedstock for catalytic cracking and hydrocracking units. This approach is highly economical and allows for the full and rational utilization of petroleum resources, aligning with the current trend of deep residue oil processing.

[0003] Among existing residue hydrotreating processes, fixed-bed residue hydrotreating is the most mature, characterized by mature technology, high product yield, good quality (desulfurization rate can reach over 90%), simple process and equipment structure, easy operation, and low investment costs. Despite its numerous advantages, fixed-bed residue hydrotreating technology still faces challenges in feedstock adaptability and long-term plant operation. Analysis of the operating results of existing residue hydrotreating units shows that a rapid increase in pressure drop is the main reason for the shortened operating cycle of fixed-bed residue hydrotreating units.

[0004] To address the issue of rapid pressure drop and short operating cycles in fixed-bed residue hydrotreating units due to catalyst bed pressure drop, one existing technical solution involves installing an upflow reactor before the conventional top-feed fixed-bed reactor to mitigate the rapid increase in pressure drop in the first and second reactors, thereby extending the operating cycle. Unlike conventional top-feed fixed-bed reactors, the upflow reactor's reactant stream enters from the bottom, exhibiting a continuous liquid phase and bubbling gas phase within the reactor. This results in slight expansion of the entire catalyst bed, reducing the reactor pressure drop. Simultaneously, deposits such as metals and coke are uniformly deposited across the entire catalyst bed rather than concentrated in a specific area, thus extending the unit's operating cycle. Another approach is to mitigate the pressure drop by controlling the properties of the feedstock. Generally, the total metal content of the feedstock for fixed-bed residue hydrotreating is controlled to be less than 150 μg / g, residual carbon less than 15 wt%, and asphaltenes content less than 5 wt%.

[0005] In summary, the deterioration of feedstock in fixed-bed residue hydrotreating is an unavoidable fact. How to cope with the long-term operation under this trend of feedstock deterioration has become a major challenge in the field of fixed-bed residue hydrotreating. Patent CN112063414A discloses an upflow residue hydrotreating reaction system and a residue hydrotreating method. By optimizing the catalyst gradation in the upflow reactor bed, it aims to extend the operating cycle of the fixed-bed unit. However, this invention only addresses bed temperature control and does not consider the impact of feedstock properties on unit operation. Patent CN114806631A uses alkane-rich materials to induce the premature precipitation of coking precursors generated during the reaction and sets up a collector to remove some of the coking precursors in advance. However, it does not consider the stability changes caused by different feedstock properties and their impact on the collection location and amount of coking precursors. Summary of the Invention

[0006] The research revealed that when two or more feedstocks with significantly different properties, such as paraffinic residue oil and naphthenic residue oil, are mixed for processing, the fourth and fifth reactors of the fixed-bed residue hydrotreating unit experience a rapid increase in bed pressure drop. This prevents further temperature increases in subsequent operations, ultimately forcing the unit to shut down for catalyst replacement and significantly shortening the unit's operating cycle. The study also found that after processing the feedstock oil in the first, second, and third reactors, due to the occurrence of the hydrogenation reaction and the limitation of diffusion, smaller molecular sizes of gums, aromatics, and saturated components are lightened. Simultaneously, because the first, second, and third reactors are mainly filled with protective agents and demetallization catalysts, their hydrogenation capacity is insufficient. Therefore, the hydrogenation saturation degree and impurity removal degree of polycyclic aromatic hydrocarbon molecules in the inferior residue oil components of crude oil from Gudao Oilfield, Fengcheng Oilfield, and Tahe Oilfield are not high, resulting in a decrease in the pectin solubility of the residue oil system, weakened stability of the entire residue oil system, and an increased tendency for asphaltenes to precipitate. Then, the residue feedstock processed in the first, second, and third reactors enters the fourth and fifth reactors. The desulfurizing and denitrifying catalysts in the fourth and fifth reactors have smaller pore sizes. Due to diffusion limitations, it is more difficult to hydrogenate and saturate the unconverted large-molecule aromatic substances in the first, second, and third reactors. Instead, only gums, aromatics, and saturated components are selectively converted. This further exacerbates the imbalance between the pectinization capacity and asphaltenes aggregation forces of the residue system, further reducing the stability of the residue system and increasing the tendency for asphaltenes to precipitate. Ultimately, this causes large molecules such as asphaltenes to aggregate and coke on the surface of the catalysts in the fourth and fifth reactors, leading to a rapid increase in bed pressure drop and a shortened operating cycle of the hydrotreating unit. Furthermore, due to diffusion limitations, the material entering the fourth and fifth reactors cannot be further converted to remove residual carbon, resulting in a high residual carbon value in the fixed-bed hydrotreating residue. This causes problems such as poor product distribution and frequent catalyst regeneration in downstream catalytic cracking units.

[0007] Currently, to improve feedstock adaptability and extend the operating cycle of fixed-bed hydrotreating units, one existing technical solution is to install an upflow reactor before the traditional top-feed fixed-bed reactor. This utilizes the advantages of the upflow reactor, such as micro-expansion, lower bed pressure drop, and greater impurity capacity, to mitigate the rapid increase in pressure drop caused by feedstock degradation. However, research has revealed that installing an upflow reactor before the top-feed fixed-bed reactor primarily considers the impact of metal deposition on the unit, neglecting the issue of decreased stability and easy precipitation of the residue oil system during hydrotreating due to inferior feedstock.

[0008] To address the shortcomings of existing technologies, this invention provides a method for hydrogenating inferior heavy oil. On the one hand, it can overcome the problem of shortened operating cycles of existing fixed-bed residue hydrogenation methods after the addition of certain inferior residue oils. On the other hand, it can improve the carbon removal efficiency of fixed-bed hydrogenation units and improve the feed quality of downstream catalytic cracking units.

[0009] A method for hydrogenating low-quality heavy oil, the method comprising the following steps:

[0010] (1) In the presence of hydrogen, the residue feedstock enters the first hydrogenation reaction zone for hydrogenation reaction;

[0011] (2) In the presence of hydrogen, the reaction effluent from the first hydrogenation reaction zone obtained in step (1) enters the second hydrogenation reaction zone for hydrogenation reaction. The second hydrogenation reaction zone is equipped with at least one on-flow reactor. The reaction products are separated by gas-liquid separation and fractionation to obtain gas products and naphtha, diesel oil and hydrogenated slag fractions.

[0012] Furthermore, in the above method, the residue feedstock in step (1) can be paraffin-based, intermediate-based, or naphthenic atmospheric residue, or it can be residue from naphthenic or intermediate-based crude oil with a high degree of aromatic ring thickening. The residue feedstock has a metal content of 60-180 μg / g, residual carbon of 6-25 wt%, and a viscosity of 50-700 mmHg at 100℃. 2 ·s -1 Preferably, the metal content is 90-150 μg / g, the residual carbon is 12-20 wt%, and the viscosity at 100℃ is 100-600 mm. 2 ·s -1 .

[0013] Furthermore, in the above method, in step (1), at least one hydrogenation reactor is set in the first hydrogenation reaction zone, preferably two to four hydrogenation reactors.

[0014] Furthermore, in the above method, the first hydrogenation reactor in the first hydrogenation reaction zone in step (1) is an upflow reactor.

[0015] Further, in the above method, the hydrogenation reactor in step (1) is provided with at least one catalyst bed, preferably two to four catalyst beds. The hydrogenation reactor is filled with a hydrogenation catalyst, which includes one or more of the following: a hydrogenation protective agent, a hydrogenation demetallization catalyst, a hydrogenation desulfurization catalyst, a hydrogenation denitrogenation catalyst, and a residual carbon conversion catalyst; the above hydrogenation catalyst includes a support and an active metal component, wherein the active metal component is generally a Group VIB and / or Group VIII metal, preferably an oxide of W, Mo, Co, or Ni; the support is a porous refractory inorganic oxide, such as at least one of alumina, silica, and zirconium oxide; the catalyst also includes an additive, which is at least one of P, Si, F, and B. The above hydrogenation catalysts can all be the catalysts used in existing fixed-bed residue hydrotreating processes, and can be commercially available products or prepared according to methods disclosed in existing literature. Further, the FZC series residue hydrotreating catalysts developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. can be used.

[0016] Furthermore, in the above method, in step (1), a feedstock rich in polycyclic aromatic hydrocarbons is introduced into the first hydrogenation reaction zone. Preferably, the feedstock rich in polycyclic aromatic hydrocarbons is introduced into any reactor downstream of the upflow reactor according to the contact sequence with the liquid phase stream. The feedstock rich in polycyclic aromatic hydrocarbons can be catalytic slurry oil and / or catalytic heavy cycle oil. The aromatic content in the feedstock rich in polycyclic aromatic hydrocarbons is not less than 60%, and the aromatic content includes monocyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. The polycyclic aromatic hydrocarbon content is not less than 55%, and the content of polycyclic aromatic hydrocarbons with three or more rings is not less than 45%, so as to enhance the stability of the residue oil system, prevent the premature precipitation of asphaltenes, and prevent the bed pressure drop in the first hydrogenation reaction zone from rising rapidly.

[0017] Furthermore, in the above method, in step (2), at least one hydrogenation reactor is set in the second hydrogenation reaction zone, preferably two to three hydrogenation reactors.

[0018] Furthermore, in the above method, the first reactor in the second hydrogenation reaction zone in step (2) is set as an upflow reactor.

[0019] Furthermore, in the above method, the upflow reactor in step (2) typically includes 2-6 catalyst beds, preferably 2-4 catalyst beds.

[0020] Furthermore, in the above method, in the upflow reactor described in step (2), according to the contact sequence with the liquid phase stream, the mass content of the active metal component of the hydrogenation catalyst, calculated as oxide, decreases sequentially in the downstream bed compared to the adjacent upstream bed, and the proportion of mesopore volume with a pore size >10nm to the total pore volume increases.

[0021] Furthermore, in the above method, in the upflow reactor described in step (2), compared with the adjacent upstream bed, the downstream bed has: a lower mass content of active metal components (calculated as oxides) by 3.0-15.0 percentage points, and a higher proportion of mesopore volume with a pore size >10nm to the total pore volume by 10.0-40.0 percentage points; preferably, the lower mass content of active metal components (calculated as oxides) by 5.0-10.0 percentage points, and a higher proportion of mesopore volume with a pore size >10nm to the total pore volume by 15.0-30.0 percentage points.

[0022] Further, in the above method, in the upflow reactor described in step (2), taking three catalyst beds as an example, the material passes through the first catalyst bed, the second catalyst bed, and the third catalyst bed in the upflow reactor from bottom to top according to the contact sequence with the material. The active metal component in the catalyst of the first catalyst bed has a mass content of 25.0%-35.0% based on oxides, and the proportion of mesopore volume with a pore size >10nm to the total pore volume is 5.0%~40.0%. The active metal component in the catalyst of the second catalyst bed has a mass content of 15.0%-24.0% based on oxides, and the proportion of mesopore volume with a pore size >10nm to the total pore volume is 30.0%-80.0%. The active metal component in the catalyst of the third catalyst bed has a mass content of 5.0%-14.0% based on oxides, and the proportion of mesopore volume with a pore size >10nm to the total pore volume is 61.0%-95.0%. The loading amounts of catalysts in the first, second, and third catalyst beds are adjusted according to the actual properties of the feedstock and product quality requirements. Specifically, in this invention, the volume ratio of the first, second, and third catalyst beds is (10%~40%):(40%~80%):(10%~30%).

[0023] Furthermore, in the above method, the hydrogenation catalyst in step (2) includes a support and an active metal component. The support is a porous, refractory inorganic oxide, such as at least one of alumina, silica, and zirconium oxide. The active metal component is generally a Group VIB and / or Group VIII metal, preferably an oxide of W, Mo, Co, or Ni. Based on the weight of the catalyst, the mass content of the active metal component in the catalyst, calculated as an oxide, is generally 5.0% to 35.0%, preferably 7.0% to 30.0%. The proportion of mesopore volume with a pore size >10 nm to the total pore volume is generally 5.0% to 95.0%, preferably 30.0% to 70.0%.

[0024] Furthermore, in the above method, the specific surface area of ​​the hydrogenation catalyst in step (2) is generally 100~300 m². 2 .g -1 The pore volume is generally 0.35~1.50 cm. 3.g -1 The total infrared acid content is generally 0.10-1.0 mmol / L.

[0025] Furthermore, in the above method, the hydrogenation reactor in step (2) further includes an upper-feed fixed-bed reactor. The catalyst bed in the upper-feed fixed-bed reactor can be filled with one or more of the following: hydrogenation protective agent, hydrogenation demetallization catalyst, hydrogenation desulfurization catalyst, hydrogenation denitrogenation catalyst, and residual carbon conversion catalyst. The catalyst type of each catalyst bed can be the same or different. All of the above catalysts can be the catalysts used in existing fixed-bed residue hydrotreating processes. Commercially available products can be selected, or they can be prepared according to methods disclosed in existing literature. Furthermore, the FZC series residue hydrotreating catalyst developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. can be selected. Even further, the above catalyst includes a support and an active component. The active component is generally a Group VIB and / or Group VIII metal, preferably an oxide of W, Mo, Co, Ni, etc. The support is a porous refractory inorganic oxide such as alumina. According to actual needs, other various additives such as P, Si, F, B, etc. can also be selectively added.

[0026] Furthermore, in the above method, the reaction products in step (2) are subjected to gas-liquid separation and fractionation to obtain gaseous products and naphtha, diesel, and hydrotreated atmospheric residue fractions. Among them, heavy diesel and hydrotreated atmospheric residue can be used as feedstocks for downstream diesel hydrorefining or catalytic cracking (or deep catalytic cracking), or can be partially recycled back to the first hydrotreating reaction zone and the second hydrotreating reaction zone. The fractionation system adopts a conventional fractionation system.

[0027] Furthermore, in the above method, the operating conditions of the first hydrogenation reaction zone in step (1) are as follows: the reaction temperature is 360℃~400℃, preferably 360℃~380℃; the reaction pressure is 10MPa~25MPa, preferably 15MPa~20MPa; the hydrogen-to-oil volume ratio is 300~1500, preferably 400~800; and the raw material oil volume hourly space velocity is 0.3h. -1 ~1.2h -1 Preferably 0.4h -1 ~0.9h -1 .

[0028] Furthermore, in the above method, the operating conditions of the second hydrogenation reaction zone in step (2) are as follows: the reaction temperature is 370℃~410℃, preferably 370℃~390℃; the reaction pressure is 10MPa~25MPa, preferably 15MPa~20MPa; the hydrogen-to-oil volume ratio is 300~1500, preferably 400~800; and the raw material oil volume hourly space velocity is 0.3h. -1 ~1.2h -1 Preferably 0.4h-1 ~0.9h -1 .

[0029] Compared with the prior art, the beneficial effects of the method of the present invention are as follows:

[0030] 1. This invention can significantly improve the feedstock adaptability of fixed-bed reactors and extend their operating cycle. Based on the understanding of the stability changes of residual oil during the hydrogenation reaction process, within the hydrogenation reaction system, the residual oil material is at its lowest stability and most likely to precipitate macromolecular substances such as asphaltenes. Therefore, at least one upflow reactor is installed in the second hydrogenation reaction zone. Utilizing the advantages of upflow reactors—micro-expansion, smaller bed pressure drop, and the ability to accommodate more impurities—the macromolecular compounds (including asphaltenes, coking precursors, catalyst dust, etc.) precipitated due to the decreased stability of the residual oil system undergo condensation and coking under hydrogen-deficient, high-temperature conditions, depositing on the catalyst bed inside the upflow reactor. This overcomes the bed blockage and rapid pressure drop caused by coking in conventional fixed-bed reactors, thereby extending the operating cycle of the reactor.

[0031] 2. This invention can significantly improve the quality of hydrogenated products through catalyst gradation. The catalyst gradation scheme in the upflow reactor set up in the second hydrogenation reaction zone is as follows: according to the contact sequence with the feed material, compared with the adjacent upstream bed, the mass content of active metal components decreases sequentially, and the proportion of mesopore volume with pore size >10nm increases. When the residue oil material passes through the upflow reactor set up in the second hydrogenation reaction zone, the molecules in the material that are easily hydrogenated are hydrogenated to saturation in the upstream bed, while the condensation and coking reactions of the difficult-to-hydrogenate viscous and aromatic macromolecules in the downstream bed occur under hydrogen-deficient and high-temperature conditions. Through feedstock property analysis, the catalyst gradation scheme of this invention enables the difficult-to-hydrogenate viscous and aromatic macromolecules to completely coke and deposit in this bed, thereby reducing the residual carbon precursors in the outlet material of the residue oil hydrogenation unit, that is, improving the feed quality of the catalytic cracking unit, reducing the residual carbon content, and improving the product distribution of the catalytic cracking unit. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of a method for hydrogenating inferior residual oil, which relates to the present invention.

[0033] Wherein, 1 is residual oil feedstock, 2 is hydrogen, 3 is the first hydrogenation reactor (upflow reactor), 4 is the outlet material of the first hydrogenation reactor, 5 is the second hydrogenation reactor, 6 is the outlet material of the second hydrogenation reactor, 7 is the third hydrogenation reactor, 8 is the outlet material of the third hydrogenation reactor, 9 is the fourth hydrogenation reactor (upflow reactor), 10 is the outlet material of the fourth hydrogenation reactor, 11 is the fifth hydrogenation reactor, and 12 is the outlet material of the fifth hydrogenation reactor.

[0034] Figure 2 This is a schematic diagram of the process flow used in Comparative Example 1 of the present invention.

[0035] Wherein, 1 is residual oil feedstock, 2 is hydrogen, 3 is the first hydrogenation reactor (upflow reactor), 4 is the outlet material of the first hydrogenation reactor, 5 is the second hydrogenation reactor, 6 is the outlet material of the second hydrogenation reactor, 7 is the third hydrogenation reactor, 8 is the outlet material of the third hydrogenation reactor, 9 is the fourth hydrogenation reactor, 10 is the outlet material of the fourth hydrogenation reactor, 11 is the fifth hydrogenation reactor, and 12 is the outlet material of the fifth hydrogenation reactor. Implementation

[0036] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings and specific examples. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims.

[0037] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight.

[0038] In the context of this specification, any two or more embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0039] The method provided by the present invention will now be described with reference to the accompanying drawings. Figure 1As shown, after the residue feedstock 1 and hydrogen 2 are mixed, they enter the first hydrogenation reaction zone (the first hydrogenation reaction zone is equipped with three hydrogenation reactors, namely the first hydrogenation reactor 3, the second hydrogenation reactor 5, and the third hydrogenation reactor 7). Specifically, the hydrogen is introduced into the first hydrogenation reactor 3 through the bottom inlet. After the reaction, the first hydrogenation reactor outlet material 4 is obtained from the top outlet of the first hydrogenation reactor 3. The first hydrogenation reactor outlet material 4 is mixed with hydrogen 2 and then enters the second hydrogenation reactor 5 through the top inlet. After the reaction, the second hydrogenation reactor outlet material 6 is obtained from the bottom of the second hydrogenation reactor 5. The second hydrogenation reactor outlet material 6 is mixed with hydrogen 2 and then enters the third hydrogenation reactor 7 through the top inlet. The hydrogenation reaction is carried out in the third hydrogenation reactor 7. After the reaction, the outlet material 8 of the third hydrogenation reactor is obtained from the bottom outlet of the third hydrogenation reactor 7. The outlet material 8 of the third hydrogenation reactor is mixed with hydrogen 2 and then enters the second hydrogenation reaction zone (the second hydrogenation reaction zone is equipped with two hydrogenation reactors, namely the fourth hydrogenation reactor 9 and the fifth hydrogenation reactor 11). Specifically, the hydrogenation reaction is carried out in the fourth hydrogenation reactor 9 from the bottom inlet. After the reaction, the outlet material 10 of the fourth hydrogenation reactor is obtained from the bottom outlet of the fourth hydrogenation reactor 9. The outlet material 10 of the fourth hydrogenation reactor is mixed with hydrogen 2 and then the outlet material 12 of the fifth hydrogenation reactor is obtained from the bottom outlet of the fifth hydrogenation reactor 11. The outlet material 12 of the fifth hydrogenation reactor then enters the subsequent separation system.

[0040] The properties of the experimental residue feedstock are shown in Table 1. Table 1 shows the properties of the feedstock for the residue hydrotreating unit. The feedstock is a mixture of vacuum residue from Kuwait, Saudi Arabia, and Tarim Basin, with a mixing ratio of Kuwait:Saudi Arabia:Tarim Basin residue = 45m%:45m%:10m%.

[0041] Table 1 Properties of Crude Oil

[0042]

[0043] Example 1

[0044] After the residual oil feedstock and hydrogen are mixed, they enter the first hydrogenation reaction zone for hydrogenation reaction. The reaction effluent from the first hydrogenation reaction zone enters the second hydrogenation reaction zone for hydrogenation reaction.

[0045] The first hydrogenation reaction zone contains three hydrogenation reactors: a first hydrogenation reactor, a second hydrogenation reactor, and a third hydrogenation reactor, with the first hydrogenation reactor being an upflow reactor. The first hydrogenation reactor is loaded with a protective agent and a demetallizing agent at a bed volume ratio of 70:30. The second hydrogenation reactor is loaded with a protective agent and a demetallizing agent along the material flow direction at a bed volume ratio of 45:55. The third hydrogenation reactor is loaded with a desulfurization catalyst. The second hydrogenation reaction zone also contains two hydrogenation reactors: a fourth hydrogenation reactor and a fifth hydrogenation reactor, with the fourth hydrogenation reactor being an upflow reactor. The fourth hydrogenation reactor has three catalyst beds, loaded with catalyst A, catalyst B, and catalyst C respectively along the material flow direction, as shown in Table 1. The fifth hydrogenation reactor has two catalyst beds, loaded with a desulfurizing agent and a carbon removal agent respectively along the material flow direction at a bed volume ratio of 20:80.

[0046] The protective agent, demetallizing agent, desulfurizing agent and carbon removal agent used in Example 1 are all commercial catalysts. The catalysts used in this example are commercial catalysts with the brand names FZC-100B, FZC-28A, FZC-33BT and FZC-41BT developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd.

[0047] In Example 1, catalysts A, B, and C, which were packed into the fourth hydrogenation reactor, were prepared using the method disclosed in patent CN114749195A. The properties of catalysts A, B, and C are shown in the table below.

[0048] Table 2 Properties of Catalyst A, Catalyst B and Catalyst C

[0049]

[0050] Table 3 Catalyst gradation scheme for the fourth hydrogenation reactor in Example 1

[0051]

[0052] Example 2

[0053] Example 2 is basically the same as Example 1, except for the catalyst gradation scheme in the fourth hydrogenation reactor, as shown in the table below.

[0054] Table 4 Catalyst gradation scheme for the fourth hydrogenation reactor in Example 2

[0055]

[0056] Example 3

[0057] Example 3 is basically the same as Example 1, except for the catalyst gradation scheme in the fourth hydrogenation reactor, as shown in the table below.

[0058] Table 5 Catalyst gradation scheme for the fourth hydrogenation reactor in Example 3

[0059]

[0060] Example 4

[0061] The process is basically the same as in Example 1, except that the material from the outlet of the first hydrogenation reactor is mixed with the catalytic slurry before entering the second hydrogenation reactor. The mass ratio of the material from the outlet of the first hydrogenation reactor to the catalytic slurry is 100:5 to improve the stability of the material, which can slow down the rate of pressure drop increase in the second and third hydrogenation reactors and improve the stability of the unit operation. Table 7 shows the properties of the catalytic slurry.

[0062] Example 5

[0063] The process is basically the same as in Example 1, except that the material from the outlet of the second hydrogenation reactor is mixed with the catalytic slurry before entering the third hydrogenation reactor. The mass ratio of the material from the outlet of the second hydrogenation reactor to the catalytic slurry is 100:10 to improve the stability of the material, which can slow down the rate of pressure drop in the third hydrogenation reactor and improve the stability of the unit operation.

[0064] Table 6 Properties of Catalytic Slurry

[0065]

[0066] Comparative Example 1

[0067] Comparative Example 1 process flow diagram is shown below Figure 2 The fourth hydrogenation reactor is basically the same as that in Example 1, except that it is a conventional top-feed fixed bed reactor, and the catalyst filling inside the reactor is only the desulfurizing agent FZC-33BT.

[0068] Comparative Example 2

[0069] It is basically the same as Example 1, except that the fourth hydrogenation reactor is only filled with hydrogenation catalyst A.

[0070] The following are the operating conditions for the examples and comparative examples.

[0071] Table 7 Operating conditions for the examples and comparative examples

[0072]

[0073] The following is a comparison of the properties of the fractions at 175~350℃ after 500 hours of operation in the examples and comparative examples.

[0074] Table 8 Properties of the 175–350 °C fractions from the Examples and Comparative Examples

[0075]

[0076] The following table shows the rate of increase in device pressure drop, with examples and comparative examples, taking 500 hours of operation as an example.

[0077] Table 9 Pressure drop after 500 hours of operation of the unit

[0078]

Claims

1. A process for the hydroprocessing of inferior heavy oils, characterized by: The method comprises the following steps: (1) in the presence of hydrogen, the residual oil feedstock enters a first hydrogenation reaction zone for hydrogenation reaction; (2) in the presence of hydrogen, the reaction effluent of the first hydrogenation reaction zone obtained in step (1) enters a second hydrogenation reaction zone for hydrogenation reaction, the second hydrogenation reaction zone is provided with at least one upflow reactor, and the reaction product is subjected to gas-liquid separation and fractionation to obtain a gas product and naphtha, diesel oil and hydrogenated residual oil fractions; The residue feed in step (1) has a metal content of 60 to 180 μg / g, a carbon residue of 6 to 25 wt%, a viscosity of 50 to 700 mm 2 ·s -1 ; In the upflow reactor in step (2), the mass content of active metal components in the form of oxides in the downstream bed layer is sequentially reduced compared with the adjacent upstream bed layer in the order of contact with the liquid phase stream, and the mesopore volume with a pore size of >10 nm accounts for an increased proportion of the total pore volume; In the upflow reactor in step (2), the mass content of active metal components in the form of oxides in the downstream bed layer is 3.0-15.0 percentage points lower than that in the adjacent upstream bed layer, and the mesopore volume with a pore size of >10 nm accounts for 10.0-40.0 percentage points higher than that in the adjacent upstream bed layer.

2. The method of claim 1, wherein: The residue feed in step (1) has a metal content of 90-150 μg / g, a carbon residue of 12-20 wt %, a viscosity of 100-600 mm 2 ·s -1 .

3. The method of claim 1, wherein: In step (1), the first hydrogenation reaction zone is provided with at least one hydrogenation reactor.

4. The method of claim 3, wherein: In step (1), the first hydrogenation reaction zone is provided with 2-4 hydrogenation reactors.

5. The method of claim 1, wherein: In step (1), the first hydrogenation reaction zone is provided with at least one hydrogenation reactor.

6. The method of claim 3, wherein: In step (1), the first hydrogenation reaction zone is provided with 2-4 hydrogenation reactors.

7. The method of claim 6, wherein: In step (1), the first hydrogenation reaction zone is provided with at least one hydrogenation reactor.

8. The method of claim 5, wherein: In step (2), the second hydrogenation reaction zone is provided with at least one hydrogenation reactor.

9. The method of claim 1, wherein: In step (2), the second hydrogenation reaction zone is provided with 2-3 hydrogenation reactors.

10. The method of claim 9, wherein: In step (2), the first reactor in the second hydrogenation reaction zone is provided as an upflow reactor.

11. The method of claim 1, wherein: In step (2), the upflow reactor comprises 2-6 catalyst bed layers.

12. The method of claim 1, wherein: In step (2), the upflow reactor comprises 2-4 catalyst bed layers.

13. The method of claim 12, wherein: In the upflow reactor in step (2), the mass content of active metal components in the form of oxides in the downstream bed layer is 5.0-10.0 percentage points lower than that in the adjacent upstream bed layer, and the mesopore volume with a pore size of >10 nm accounts for 15.0-30.0 percentage points higher than that in the adjacent upstream bed layer.

14. The method of claim 1, wherein: ​ 15. The method of claim 1, wherein: In the up-flow reactor in step (2), the materials pass through the first catalyst bed, the second catalyst bed and the third catalyst bed in the up-flow reactor in turn from bottom to top according to the contact sequence of the streams; the mass content of the active metal component in the catalyst in the first catalyst bed is 25.0%-35.0% in terms of oxide, and the proportion of the mesopore volume with a pore size >10 nm in the total pore volume is 5.0%-40.0%; the mass content of the active metal component in the catalyst in the second catalyst bed is 15.0%-24.0% in terms of oxide, and the proportion of the mesopore volume with a pore size >10 nm in the total pore volume is 30.0%-80.0%; the mass content of the active metal component in the catalyst in the third catalyst bed is 5.0%-14.0% in terms of oxide, and the proportion of the mesopore volume with a pore size >10 nm in the total pore volume is 61.0%-95.0%.

16. The method of claim 15, wherein: The volume ratio of the first catalyst bed, the second catalyst bed and the third catalyst bed in step (2) is (10%-40%):(40%-80%):(10%-30%).

17. The method of claim 1, wherein: The hydrogenation catalyst in step (2) comprises a carrier and an active metal component, the carrier is at least one of alumina, silica and zirconia, and the active metal component is a group VIB and / or VIII metal; the mass content of the active metal component in the catalyst is 5.0%-35.0% in terms of oxide based on the weight of the catalyst; the proportion of the mesopore volume with a pore size >10 nm in the total pore volume of the catalyst is 5.0%-95.0%.

18. The method of claim 17, wherein: The mass content of the active metal component in the catalyst is 7.0%-30.0% in terms of oxide based on the weight of the catalyst; the proportion of the mesopore volume with a pore size >10 nm in the total pore volume of the catalyst is 30.0%-70.0%.

19. The method of claim 17, wherein: The specific surface area of the hydrogenation catalyst in step (2) is 100-300 m 2 .g -1 The pore volume is 0.35-1.00 cm 3 .g -1 The total infrared acid amount is 0.10-1.0 mmol / L.

20. The method of claim 1, wherein: In step (2), the diesel and / or the hydrogenated heavy residue part is recycled to the first hydrogenation reaction zone and the second hydrogenation reaction zone.

21. The method of claim 1, wherein: The operating conditions of the first hydrogenation reaction zone in step (1) are as follows: the reaction temperature is 360°C to 400°C; the reaction pressure is 10 MPa to 25 MPa; the hydrogen / oil volume ratio is 300 to 1500; the liquid hourly space velocity of the raw material oil is 0.3 h -1 ~ 1.2 h -1 .

22. The method of claim 21, wherein: The operating conditions of the first hydrogenation reaction zone in step (1) are as follows: the reaction temperature is 360°C to 380°C; the reaction pressure is 15 MPa to 20 MPa; the hydrogen / oil volume ratio is 400 to 800; the liquid hourly space velocity of the raw material oil is 0.4 h -1 ~ 0.9 h -1 .

23. The method of claim 1, wherein: The operating conditions of the second hydrogenation reaction zone in step (2) are as follows: reaction temperature is 370°C to 410°C; reaction pressure is 10 MPa to 25 MPa; hydrogen / oil volume ratio is 300 to 1500; and liquid hourly space velocity of the raw material oil is 0.3 h -1 ~ 1.2 h -1 .

24. The method of claim 23, wherein: The operating conditions of the second hydrogenation reaction zone in step (2) are as follows: reaction temperature is 370°C to 390°C; reaction pressure is 15 MPa to 20 MPa; hydrogen / oil volume ratio is 400 to 800; and liquid hourly space velocity of the raw material oil is 0.4 h -1 ~ 0.9 h -1 .

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