Hydroconversion of inferior heavy oil and system

Abstract

The present disclosure relates to a method and system for hydrogen conversion of inferior heavy oil, which comprises the following steps: (1) performing first hydrogenation reaction on inferior heavy oil to obtain first hydrogenation product; (2) performing first gas-liquid separation and second gas-liquid separation on the first hydrogenation product to obtain second gas phase product and second liquid phase product; (3) performing first fractionation on the second liquid phase product to obtain first fractionation product; (4) combining the first gas phase product, the second gas phase product and the first fractionation product and then performing second hydrogenation reaction to obtain second hydrogenation product; (5) performing third gas-liquid separation and fourth gas-liquid separation on the second hydrogenation product to obtain fourth gas phase product and fourth liquid phase product; (6) combining the third liquid phase product and the fourth liquid phase product and then performing fractionation to obtain fractionation product. The present disclosure can realize clean and efficient utilization of inferior heavy oil, has high liquid product yield and stable product quality.

Description

Technical Field

[0001] This disclosure relates to a method and system for the hydroconversion of inferior heavy oil. Background Technology

[0002] In recent years, the trend of crude oil becoming heavier and of lower quality has become increasingly serious. The main characteristics of low-quality heavy oil are high density, high sulfur and nitrogen content, high residual carbon, high acid value, and high heavy metal content. At the same time, increasingly stringent environmental protection requirements, increased market demand for light oil products, and continuously rising requirements for cleaner petroleum products have brought multiple challenges to refining and chemical enterprises, including technological, economic, and environmental ones.

[0003] The processing of low-quality heavy oil falls into two main categories: decarbonization and hydrotreating. Decarbonization processes primarily include delayed coking and viscosity-reducing cracking; while hydrotreating processes mainly include fixed-bed hydrotreating, fluidized-bed hydrotreating, moving-bed hydrotreating, and slurry-bed hydrotreating. Among heavy oil hydrotreating technologies, the fixed-bed process is simple, mature, and easy to operate, making it the most widely used process. However, this process has strict limitations on the content of residual carbon and heavy metals in the feedstock, which can easily lead to catalyst deactivation and bed blockage. Fluidized-bed and moving-bed technologies can process low-quality heavy oil and have relatively wide feedstock adaptability, but their drawbacks include complex control, higher operating costs, and higher investment. Slurry-bed hydrotreating technology can also process low-quality heavy oil, with lower reaction pressures than moving-bed and fluidized-bed technologies, a wider range of operational flexibility, and relatively lower investment. However, it also suffers from complex control and higher energy consumption.

[0004] Due to the high asphaltenes and sulfur and nitrogen content in inferior heavy oil, the naphtha and diesel fractions after hydrotreating still need to be sent to downstream units for further processing. This not only increases energy consumption, investment, and processing costs but also significantly reduces the efficiency of utilizing inferior heavy oil. Existing technologies have improved processes and equipment, which can improve product properties to some extent, but problems such as low conversion rates, unstable product quality, complex operation, poor system stability, increased equipment investment, and safety hazards still exist. Summary of the Invention

[0005] The purpose of this disclosure is to provide a method and system for the hydroconversion of inferior heavy oil, so as to improve the conversion rate, liquid product yield and product quality of inferior heavy oil.

[0006] To achieve the above objectives, the first aspect of this disclosure provides a method for hydrogenating inferior heavy oil, the method comprising the following steps:

[0007] (1) Inferior heavy oil and hydrogen-containing gas are contacted with the first hydrogenation catalyst to carry out the first hydrogenation reaction and obtain the first hydrogenation product;

[0008] (2) The first hydrogenation product is subjected to a first gas-liquid separation to obtain a first gas phase product and a first liquid phase product; and at least a portion of the first liquid phase product is subjected to a second gas-liquid separation to obtain a second gas phase product and a second liquid phase product.

[0009] (3) The second liquid phase product is subjected to a first fractionation to obtain a first bottom distillate and a first fractionation product, wherein the boiling point of the first fractionation product is in the range of 80-360℃.

[0010] (4) The first gaseous product, the second gaseous product and the first fractionated product are combined and then contacted with the second hydrogenation catalyst to carry out the second hydrogenation reaction to obtain the second hydrogenation product.

[0011] (5) The second hydrogenation product is subjected to a third gas-liquid separation to obtain a third gas phase product and a third liquid phase product; and the third gas phase product is subjected to a fourth gas-liquid separation to obtain a fourth gas phase product and a fourth liquid phase product.

[0012] (6) The third liquid phase product and the fourth liquid phase product are combined and then subjected to a second fractionation to obtain the second bottom distillate and the second fractionation product.

[0013] Optionally, in step (1), the inferior heavy oil is selected from at least one of heavy oil, residual oil, deoiled bitumen, deasphalted oil, coal tar, oil sands, shale oil and crude oil;

[0014] The properties of the inferior heavy oil include at least one of the following: nickel content of 5-120 μg / g, vanadium content of 20-1200 μg / g, residual carbon value of not less than 5% by weight, asphaltene content of greater than 2.2% by weight, final boiling point of greater than 360℃, and API gravity of less than 25.

[0015] The active components of the first hydrogenation catalyst include metal components and non-metal components, wherein the metal components are selected from at least one group IIIB, IVB, VB, VIB, and VIII metal compounds, preferably from at least one group IIIB, VB, VIB, and VIII metal compounds; and the non-metal components are selected from at least one group VA, IVA, VIA, and VIIA non-metal compounds, preferably from at least one group VA, IVA, and VIA non-metal compounds.

[0016] Based on 100 parts by weight of the aforementioned inferior heavy oil, the amount of the first hydrogenation catalyst is 0.001-1.0 parts by weight;

[0017] The conditions for the first hydrogenation reaction include: a temperature of 330-435℃, a hydrogen partial pressure of 8-24 MPa, and a fresh feed volume hourly space velocity of 0.005-1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 650-3000.

[0018] Optionally, in step (2), the conditions for the first gas-liquid separation include: temperature 330-435℃ and pressure 9-26MPa;

[0019] The conditions for the second gas-liquid separation include: temperature 330-435℃ and pressure 9-26MPa.

[0020] Optionally, the method may further include: returning at least a portion of the first liquid phase product to carry out the first hydrogenation reaction;

[0021] The weight ratio of the first liquid phase product from the first hydrogenation reaction to the inferior heavy oil is (0.1-6):1.

[0022] Optionally, in step (3), the operating conditions for the first fractionation include: pressure 0.1-1.0 MPa, temperature 280-400℃; and / or, the operating conditions for the first fractionation include: vacuum degree 5-40 mmHg, temperature 280-400℃.

[0023] Optionally, in step (4), the active component of the second hydrogenation catalyst is selected from at least one of Co-Mo, Ni-Mo, Ni-W, Co-W, Co-Mo-W, and Ni-Mo-W, preferably from at least one of Co-Mo-W and Ni-Mo-W;

[0024] Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionated product, the amount of the second hydrogenation catalyst is 0.001-1.0 parts by weight.

[0025] The conditions for the second hydrogenation reaction include: temperature 330-435℃, hydrogen partial pressure 8-22 MPa, and volume hourly space velocity (VHSV) of 0.01-2.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 650-5000.

[0026] Optionally, in step (5), the conditions for the third gas-liquid separation include: temperature 330-435℃ and pressure 9-26MPa;

[0027] The conditions for the fourth gas-liquid separation include: temperature 330-435℃ and pressure 9-26MPa.

[0028] Optionally, the method further includes: desulfurizing the fourth gaseous product and optionally membrane separating it to obtain a hydrogen-rich gas, and returning at least a portion of the hydrogen-rich gas to the first hydrogenation reaction.

[0029] Optionally, in step (6), the operating conditions for the second fractionation include: pressure 0.1-1.0 MPa and temperature 280-360 °C;

[0030] And / or, the operating conditions for the second fractionation include: a vacuum of 5-40 mmHg and a temperature of 280-390 °C.

[0031] Optionally, the method further includes:

[0032] The first portion of the first bottom distillate and / or the first portion of the second bottom distillate are returned to the first hydrogenation reaction, and the second portion of the first bottom distillate and / or the second portion of the second bottom distillate are discharged externally.

[0033] The weight ratio of the first bottom distillate and / or the second bottom distillate to the inferior heavy oil is (0.01-4):1;

[0034] The weight ratio of the first bottom distillate of the second part and / or the second bottom distillate of the second part to the inferior heavy oil is (0.001-0.08):1.

[0035] A second aspect of this disclosure provides a system for performing the method described in the first aspect of this disclosure. The system includes a first hydrogenation reaction unit, a first separation unit, a second hydrogenation reaction unit, a second separation unit, and a second fractionation unit connected in sequence. The first separation unit includes a first gas-liquid separator and a second gas-liquid separator connected in sequence. The second separation unit includes a third gas-liquid separator and a fourth gas-liquid separator connected in sequence. The first separation unit is also connected to the first fractionation unit.

[0036] Furthermore, the system also includes a feedstock oil unit, a feedstock oil heating unit, a hydrogen heating unit, a desulfurization unit, a membrane separation unit, a hydrogen-containing gas unit, a vacuum unit, and a catalyst unit. The feedstock oil unit, the hydrogen-containing gas unit, and the catalyst unit are respectively connected to the feedstock oil heating unit. The hydrogen-containing gas unit is connected to the feedstock oil heating unit via the hydrogen heating unit. The feedstock oil heating unit and the hydrogen heating unit are respectively connected to the first hydrogenation reaction unit to respectively feed the heated material into the first hydrogenation reaction unit for the first hydrogenation reaction. The second separation unit is sequentially connected to the desulfurization unit, the membrane separation unit, and the hydrogen-containing gas unit. The vacuum unit is connected to the first fractionation unit. The first fractionation unit and / or the second fractionation unit are also connected to the first hydrogenation reaction unit.

[0037] Furthermore, the reactor used in the first hydrogenation reaction unit is a slurry bed reactor and / or a moving bed reactor;

[0038] Furthermore, the reactor used in the second hydrogenation reaction unit is a fixed-bed reactor.

[0039] Through the above technical solution, this disclosure adopts a two-stage series hydrogenation process. Inferior heavy oil undergoes mild hydrothermal cracking in the first hydrogenation reaction. The product after the reaction undergoes two gas-liquid separations to obtain light, medium, and heavy fractions. The heavy fraction undergoes a first fractionation. The light, medium, and first fractionation products are then hydrogenated and refined in a second hydrogenation reaction. The refined product undergoes two more gas-liquid separations, and the resulting liquid products are combined for a second fractionation, ultimately yielding a high-quality hydrogenated product. This achieves clean and efficient utilization of inferior heavy oil, with high conversion rate of inferior heavy oil, high yield of liquid products, stable product quality, small system equipment footprint, low hydrogen and energy consumption, and the ability to achieve long-term stable operation.

[0040] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 A block flow diagram illustrating a specific embodiment of the method for hydroconversion of inferior heavy oil provided in this disclosure is shown.

[0043] Figure 2 A schematic diagram of the process flow of the first specific embodiment of the method for hydroconversion of inferior heavy oil provided in this disclosure is shown.

[0044] Figure 3 A schematic diagram of the process flow for a second specific embodiment of the method for hydroconversion of inferior heavy oil provided in this disclosure is shown.

[0045] Figure 4 A schematic diagram of the process flow of the third specific embodiment of the method for hydroconversion of inferior heavy oil provided in this disclosure is shown.

[0046] Figure 5 A schematic diagram of the process flow of the fourth specific embodiment of the method for hydroconversion of inferior heavy oil provided in this disclosure is shown.

[0047] Explanation of reference numerals in the attached figures

[0048] A101—Federal feedstock unit; A102—Federal feedstock heating unit; A103—Hydrogen heating unit; A104—First hydrogenation reaction unit; A105—First separation unit; A106—Second hydrogenation reaction unit; A107—Second separation unit; A108—Desulfurization unit; A109—Membrane separation unit; A110—Hydrogen-containing gas unit; A111—Second fractionation unit; A112—First fractionation unit; A113—Vacuum pumping unit; A114—Catalyst unit;

[0049] 101—Feedstock oil tank; 102—Feedstock oil booster pump; 103—Mixed hydrogen oil heater; 104—Hydrogen heater; 105—First hydrogenation reactor; 106—First high-pressure separator; 107—Second high-pressure separator; 108—Second hydrogenation reactor; 109—Third high-pressure separator; 110—Fourth high-pressure separator; 111—Second fractionation tower; 112—Desulfurization tower; 113—Amine liquid pump; 114—Amine liquid tank; 115—Membrane separator; 116—Circulating hydrogen compressor; 117—Circulating oil pump; 118—First fractionation tower; 120—Catalyst tank; 121—Catalyst feed pump;

[0050] S1—Feedstock oil; S2—Pressurized feedstock oil; S3—Pressurized hydrogen-mixed feedstock oil; S4—Heated feedstock oil; S5—Second hydrogen-mixed oil; S6—First hydrogen-mixed oil; S7—Heated hydrogen-mixed oil; S8—First hydrogenation product; S9—First gaseous product; S10—First liquid product; S11—Second gaseous product; S12—Second liquid product; S13—Gas feed; S14—Second hydrogenation product; S15—Third liquid product; S16—Third gaseous product; S17—Fourth gaseous product; S18—Fourth liquid product; S19—Second fractionation product S20—Third fraction product; S21—Fourth fraction product; S22—Fifth fraction product; S23—Second bottom distillate; S24—First circulating bottom distillate; S25—First external tail oil; S26—Amine-rich liquid; S27—Amine-lean liquid; S28—Desulfurization high-grade gas; S29—Circulating hydrogen; S30—New hydrogen; S31—Circulating oil; S32—First fraction product; S33—First bottom distillate; S34—Second circulating bottom distillate; S35—Second external tail oil; S41—Fresh catalyst; S42—Pumped catalyst. Detailed Implementation

[0051] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0052] In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its normal operating state, while "inner" and "outer" refer to their position relative to the device's outline. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0053] The first aspect of this disclosure provides a method for the hydroconversion of inferior heavy oil, referencing... Figures 1 to 5 The method includes the following steps:

[0054] (1) Inferior heavy oil and hydrogen-containing gas are contacted with the first hydrogenation catalyst to carry out the first hydrogenation reaction and obtain the first hydrogenation product;

[0055] (2) The first hydrogenation product is subjected to a first gas-liquid separation to obtain a first gas phase product and a first liquid phase product; and at least a portion of the first liquid phase product is subjected to a second gas-liquid separation to obtain a second gas phase product and a second liquid phase product.

[0056] (3) The second liquid phase product is subjected to a first fractionation to obtain a first bottom distillate and a first fractionation product, wherein the boiling point of the first fractionation product is in the range of 80-360℃.

[0057] (4) The first gaseous product, the second gaseous product and the first fractionated product are combined and then contacted with the second hydrogenation catalyst to carry out the second hydrogenation reaction to obtain the second hydrogenation product.

[0058] (5) The second hydrogenation product is subjected to a third gas-liquid separation to obtain a third gas phase product and a third liquid phase product; and the third gas phase product is subjected to a fourth gas-liquid separation to obtain a fourth gas phase product and a fourth liquid phase product.

[0059] (6) The third liquid phase product and the fourth liquid phase product are combined and then subjected to a second fractionation to obtain the second bottom distillate and the second fractionation product.

[0060] According to this disclosure, in step (1), the properties of the inferior heavy oil include at least one of the following: nickel content of 5-120 μg / g, vanadium content of 20-1200 μg / g, residual carbon value of not less than 5% by weight, asphaltene content of greater than 2.2% by weight, final boiling point of greater than 360℃, and API gravity of less than 25. Preferably, the final boiling point of the inferior heavy oil is greater than 500℃, more preferably greater than 524℃, and the asphaltene content is preferably greater than 8% by weight, more preferably greater than 16% by weight. The inferior heavy oil can be at least one selected from heavy oil, residual oil, deoiled bitumen, deasphalted oil, coal tar, oil sands, shale oil, and crude oil, and is preferably selected from at least one selected from inferior heavy oil, residual oil, deoiled bitumen, coal tar, oil sands, shale oil, and crude oil. Wherein, heavy oil refers to residue oil or distillate oil with a boiling point greater than 350℃, and distillate oil refers to heavy diesel oil, heavy gas oil, catalyst feedstock, slurry oil, and lubricating oil fractions; residue oil refers to the bottom distillate separated from the bottom of an atmospheric or vacuum distillation tower, with atmospheric residue (boiling point generally greater than 350℃) and vacuum residue (boiling point generally greater than 500℃) being the bottom distillate; de-asphalted bitumen refers to the byproduct of solvent deasphalting in residue oil processing; and deasphalted oil refers to the residue remaining after solvent deasphalting removes most of the saturated hydrocarbons and low-fraction aromatic hydrocarbons from vacuum residue, consisting of asphaltenes, resins, aromatics, and a small amount of saturated components. The composition includes: coal tar, a black or dark brown viscous liquid with a pungent odor produced during coal dry distillation; oil sand, also known as bitumen sand, is a type of sandstone or other rock containing natural bitumen, typically a mixture of sand, bitumen, minerals, clay, and water; shale oil refers to petroleum resources contained in shale formations, including petroleum in the pores and fractures of mudstone and shale, as well as petroleum resources in adjacent and interlayered layers of dense carbonate or clastic rocks within mudstone and shale formations; and crude oil, a dark brown, viscous, oily liquid with a green fluorescence and a distinctive odor, which is a mixture of various liquid hydrocarbons such as alkanes, cycloalkanes, aromatics, and alkenes. The inferior heavy oil described in this disclosure can be one of the above-mentioned oils or a mixture of several oils. The method of this disclosure has the characteristic of strong raw material adaptability and can be widely applied to the catalytic hydrogenation of various inferior heavy oils mentioned above.

[0061] The presence of impurities such as asphaltenes, metallic nickel and vanadium, and non-metallic sulfur and nitrogen in inferior heavy oil has various adverse effects on the processing, often clogging pipelines and equipment, causing catalyst deactivation, and shortening the operating cycle. The first hydrotreating reaction can mitigate hydrothermal cracking, remove impurities such as metals, sulfur and nitrogen, and asphaltenes from the feedstock, and reduce the impact on subsequent operations.

[0062] The hydrogen content in the hydrogen-containing gas can be 85% by volume or more, and can include new hydrogen and recycled hydrogen. New hydrogen refers to the hydrogen that participates in the reaction for the first time, and recycled hydrogen refers to the hydrogen-rich gas obtained in subsequent steps and returned for use in the first hydrogenation reaction.

[0063] The first hydrogenation catalyst can be any common catalyst suitable for hydrogenating low-quality heavy oil. In one specific embodiment, the active components of the first hydrogenation catalyst include metallic and non-metallic components. The metallic component can be selected from at least one group IIIB, IVB, VB, VIB, and VIII metal compounds, preferably at least one group IIIB, VB, VIB, and VIII metal compounds, and more preferably at least one group VB, VIB, and VIII metal compounds. The non-metallic component can be selected from at least one group VA, IVA, VIA, and VIIA non-metallic compound, preferably at least one group VA, IVA, and VIA non-metallic compound, and more preferably at least one group VA and IVA non-metallic compound. Preferably, the first hydrogenation catalyst is a liquid catalyst suitable for a slurry bed reactor.

[0064] The conditions for the first hydrogenation reaction may include: a temperature of 330-435℃, preferably 360-430℃; a hydrogen partial pressure of 8-24 MPa, preferably 12-20 MPa; and a volume hourly space velocity (VHSV) of 0.005-1.5 h⁻¹ for the fresh feedstock. -1 Preferably, it is 0.01-0.85h. -1 The hydrogen-to-oil volume ratio is 650-3000, preferably 800-2000. Based on 100 parts by weight of the inferior heavy oil, the amount of the first hydrogenation catalyst can be 0.001-1.0 parts by weight, preferably 0.005-0.8 parts by weight, and more preferably 0.01-0.06 parts by weight.

[0065] In step (1), the first hydrogenation reaction of the inferior heavy oil can achieve a high feed conversion rate, thereby allowing more lower boiling point components (e.g., components with boiling points below 350°C) to undergo a subsequent second hydrogenation reaction, thereby increasing the yield of liquid phase products and reducing the discharge of tailings and gas yield. Specifically, the conversion rate of asphaltenes in the inferior heavy oil can be 31-85%, and the conversion rate of heavy fractions can be 20-80%.

[0066] According to this disclosure, in step (2), the conditions for the first gas-liquid separation may include: a temperature of 330-435℃, preferably 360-430℃; and a pressure of 9-26MPa, preferably 14-24MPa. The conditions for the second gas-liquid separation may include: a temperature of 330-435℃, preferably 360-430℃; and a pressure of 9-26MPa, preferably 14-24MPa.

[0067] After the second gas-liquid separation, the content of the fraction below 360°C in the second liquid phase product is not more than 6.5% by weight, and the content of the fraction between 360°C and 530°C is not less than 30% by weight.

[0068] In one specific implementation, reference is made to... Figure 4 and Figure 5 The method may further include: returning at least a portion of the first liquid phase product to the first hydrogenation reaction. Further, the weight ratio of the portion of the first liquid phase product returned to the first hydrogenation reaction to the inferior heavy oil may be (0.1-6):1; preferably (0.1-4):1. Recycling at least a portion of the first liquid phase product for the first hydrogenation reaction helps maintain temperature uniformity within the first hydrogenation reactor, avoids hot spots leading to coking and blockage, and improves product quality.

[0069] According to this disclosure, in step (3), the second liquid product is preferably sent to the first fractionation tower for first fractionation under heat preservation and pressure preservation conditions. Specifically, the heat preservation and pressure preservation conditions may include: temperature of 120-420℃, preferably 220-380℃, and pressure of 0.35-2MPa, preferably 0.5-1.5MPa.

[0070] The first fractionation can be carried out under atmospheric and / or reduced pressure conditions. Specifically, the operating conditions for the first fractionation may include: pressure 0.1-1.0 MPa, temperature 280-400℃, and / or, the operating conditions for the first fractionation may include: vacuum degree 5-40 mmHg, temperature 280-400℃. The boiling point of the bottom distillate of the first column is greater than 520℃.

[0071] According to this disclosure, in step (4), the first gaseous product, the second gaseous product and the first fractionated product are combined to carry out a second hydrogenation reaction, including hydrogenation saturation, desulfurization and denitrification reactions.

[0072] The second hydrogenation catalyst can be any common catalyst suitable for hydrogenating low-quality heavy oil. In one specific embodiment, the active component of the second hydrogenation catalyst is selected from at least one of Co-Mo, Ni-Mo, Ni-W, Co-W, Co-Mo-W, and Ni-Mo-W, preferably at least one of Co-Mo-W and Ni-Mo-W.

[0073] The conditions for the second hydrogenation reaction include: a temperature of 330-435℃, preferably 360-430℃; a hydrogen partial pressure of 8-22 MPa, preferably 12-18 MPa; and a volume hourly space velocity of 0.01-2.0 h⁻¹. -1 Preferably, it is 0.01-1.5h. -1The hydrogen-to-oil volume ratio is 650-5000, preferably 800-3000. Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionation product, the amount of the second hydrogenation catalyst can be 0.001-1.0 parts by weight, preferably 0.005-0.8 parts by weight.

[0074] This disclosed method employs a two-stage hydrogenation process in series, with the first and second hydrogenation reactions sharing a single hydrogen system. Compared to conventional two-stage hydrogenation systems, this not only reduces the number of compressors and equipment footprint, lowering equipment investment, but also rationally utilizes the pressure difference between the two hydrogenation reactions, fully leveraging hydrogen resources and minimizing overall hydrogen consumption. Furthermore, by configuring different hydrogenation catalysts, operating costs can be effectively reduced and the conversion efficiency of low-quality heavy oil resources can be improved.

[0075] According to this disclosure, in step (5), the conditions for the third gas-liquid separation may include: a temperature of 330-435℃, preferably 350-430℃; and a pressure of 9-26MPa, preferably 10-20MPa. The conditions for the fourth gas-liquid separation may include: a temperature of 330-435℃, preferably 350-430℃; and a pressure of 9-26MPa, preferably 10-20MPa.

[0076] The third and fourth gas-liquid separations can recover hydrogen resources from the gaseous products. In one specific embodiment, the method further includes: desulfurizing the fourth gaseous product and optionally membrane separation to obtain hydrogen-rich gas, and returning at least a portion of the hydrogen-rich gas to the first hydrogenation reaction, i.e., the hydrogen-rich gas is used as recycled hydrogen. The hydrogen purity of the hydrogen-rich gas is greater than 93% by volume, and it can be combined with fresh hydrogen as the hydrogen-containing gas. The desulfurization is used to remove sulfur-containing compounds from the gaseous products, and the conditions may include: a pressure of 9-24 MPa, and a sulfur content of no more than 50 ppm in the desulfurized gaseous products; the desulfurization can be carried out using a wet alkanolamine method. The membrane separation is used to remove hydrocarbon molecules from the gaseous products, which helps maintain the recycled hydrogen concentration, meets the hydrogen partial pressure in the system, and reduces losses caused by vented gases; the conditions for membrane separation may include: a pressure of 9-24 MPa. In addition to being returned for the first hydrogenation reaction, a portion of the hydrogen-rich gas can be vented to maintain the hydrogen purity of the hydrogen-containing gas in the first hydrogenation reaction at more than 85% by volume.

[0077] According to this disclosure, in step (6), the third liquid phase product and the fourth liquid phase product are preferably sent to the second fractionation tower for second fractionation under heat preservation and pressure preservation conditions. Specifically, the heat preservation and pressure preservation conditions may include: temperature of 120-420℃, preferably 220-380℃, and pressure of 0.35-2MPa, preferably 0.5-1.5MPa.

[0078] The second fractionation can be carried out under positive and / or negative pressure conditions. When the second fractionation is carried out under positive pressure conditions, the operating conditions include: pressure 0.1-1.0 MPa, temperature 280-360℃, and the cut-off point of the light fraction not lower than 480℃; when the second fractionation is carried out under negative pressure conditions, the operating conditions include: vacuum degree 5-40 mmHg, temperature 280-390℃, and the cut-off point of the light fraction not higher than 300℃.

[0079] The second fractionation product, i.e., the hydrogenated product, may include distillates such as naphtha, gasoline, jet fuel, diesel, and wax oil. The boiling point of the second bottom distillate is greater than 520°C.

[0080] According to this disclosure, in order to further improve the conversion efficiency of inferior heavy oil, maintain the stability of the first hydrogenation reaction unit, and promptly remove deactivated and coking catalyst, the method may further include: returning a first portion of the first bottom distillate and / or a first portion of the second bottom distillate to the first hydrogenation reaction, and discharging a second portion of the first bottom distillate and / or a second portion of the second bottom distillate. Further, the weight ratio of the first portion of the first bottom distillate and / or the first portion of the second bottom distillate to the inferior heavy oil is (0.01-4):1, preferably (0.5-2):1. The weight ratio of the second portion of the first bottom distillate and / or the second portion of the second bottom distillate to the inferior heavy oil is (0.001-0.08):1, preferably (0.02-0.05):1. By controlling the flow rates of the bottom distillate described in the first part and the bottom distillate described in the second part, not only can the operational flexibility and range of this method be further improved, but the stability of the first hydrogenation reaction unit can also be further maintained, avoiding problems such as catalyst coking and deactivation, and blockage of reactors or pipelines caused by gas phase deviation, thus ensuring long-term stable operation of the unit.

[0081] Furthermore, the circulating oil (the first portion of the first bottom distillate and / or the first portion of the second bottom distillate) can be mixed with the inferior heavy oil and pressurized, and then mixed evenly with the first hydrogenation catalyst and circulating hydrogen (hydrogen-rich gas obtained by desulfurization and membrane separation of the fourth gas phase product) before the first hydrogenation reaction is carried out.

[0082] A second aspect of this disclosure provides a substandard heavy oil hydrogenation system for performing the above-described method, with reference to... Figure 1The system includes a first hydrogenation reaction unit A104, a first separation unit A105, a second hydrogenation reaction unit A106, a second separation unit A107, and a second fractionation unit A111 connected in sequence; the first separation unit A105 includes a first gas-liquid separator and a second gas-liquid separator connected in sequence, and the second separation unit A107 includes a third gas-liquid separator and a fourth gas-liquid separator connected in sequence; the first separation unit A105 is also connected to the first fractionation unit A112.

[0083] Furthermore, the system also includes a feedstock oil unit A101, a feedstock oil heating unit A102, a hydrogen heating unit A103, a desulfurization unit A108, a membrane separation unit A109, a hydrogen-containing gas unit A110, a vacuum unit A113, and a catalyst unit A114.

[0084] The feedstock oil unit A101 is used to contain the inferior heavy oil. The feedstock oil unit A101, the hydrogen-containing gas unit A110, and the catalyst unit A114 are respectively connected to the feedstock oil heating unit A102 to respectively feed each feedstock into the feedstock oil heating unit A102 for heating. The hydrogen-containing gas unit A110 can be connected to the feedstock oil heating unit A102 via a hydrogen heating unit A103. The feedstock oil heating unit A102 and the hydrogen heating unit A103 are respectively connected to the first hydrogenation reaction unit A104 to respectively feed the heated materials into the first hydrogenation reaction unit A104 for the first hydrogenation reaction.

[0085] The second separation unit A107 is sequentially connected to the desulfurization unit A108, the membrane separation unit A109, and the hydrogen-containing gas unit A110, so as to desulfurize and membrane separate the fourth gaseous product obtained by the second separation unit A107 and recycle it for the first hydrogenation reaction.

[0086] The vacuum unit A113 is connected to the first fractionation unit A112 and is used to provide the operating conditions for the first fractionation.

[0087] The first fractionation unit A112 and / or the second fractionation unit A111 may also be connected to the first hydrogenation reaction unit A104 to return the circulating oil to the first hydrogenation reaction unit A104.

[0088] Further, refer to Figures 2 to 4 The raw material oil unit A101 may include a raw material oil tank 101 and a raw material oil booster pump 102; the raw material oil heating unit A102 may include a hydrogen-mixed oil heater 103; the hydrogen heating unit A103 may include a hydrogen heater 104.

[0089] The first hydrogenation reaction unit A104 includes a first hydrogenation reactor 105. The first hydrogenation reactor 105 can be at least one of a slurry bed reactor, a suspended bed reactor, a fluidized bed reactor, a fixed bed reactor, and a moving bed reactor, preferably at least one of these. More preferably, the first hydrogenation reactor 105 is a slurry bed reactor and / or a moving bed reactor, which can adapt to the poor characteristics of the feedstock and has a wide range of operational adaptability.

[0090] The second hydrogenation reaction unit A106 includes a second hydrogenation reactor 108. The second hydrogenation reactor 108 can be at least one of a slurry bed reactor, a suspended bed reactor, a fluidized bed reactor, a fixed bed reactor, and a moving bed reactor, preferably at least one of a slurry bed reactor, a fixed bed reactor, and a moving bed reactor. More preferably, the second hydrogenation reactor 108 is a fixed bed reactor, capable of hydrogenation refining of low-boiling-point fractions.

[0091] The first, second, third, and fourth gas-liquid separators can each be high-pressure separators. The first separation unit A105 may include a first high-pressure separator 106 and a second high-pressure separator 107. The second separation unit A107 may include a third high-pressure separator 109 and a fourth high-pressure separator 110.

[0092] The desulfurization unit A108 may include a desulfurization tower 112, an amine liquid pump 113, and an amine liquid tank 114, wherein the amine liquid pump 113 and the amine liquid tank 114 are used for transporting and storing amine liquid, respectively. An exhaust gas pipeline (not shown in the figure) may be installed at the outlet of the desulfurization tower 112.

[0093] The membrane separation unit A109 may include a membrane separator 115.

[0094] The hydrogen-containing gas unit A110 may include a circulating hydrogen compressor 116.

[0095] The first fractionation unit A112 may include a first fractionation column 118. The second fractionation unit A111 may include a second fractionation column 111.

[0096] The catalyst unit A114 may include a catalyst tank 120 and a catalyst feed pump 121.

[0097] The present disclosure will be further illustrated by the following examples, but the present disclosure is not limited thereto.

[0098] Unless otherwise specified, all materials, reagents, instruments, and equipment used in the embodiments of this disclosure are commercially available.

[0099] Example 1

[0100] In this embodiment, a mixture of a certain slag reducing agent and catalytic oil slurry is used as feedstock, denoted as No. 1 feedstock, and its properties are shown in Table 1.

[0101] This embodiment uses, as follows: Figure 1 The illustrated inferior heavy oil hydrotreating system includes a feedstock unit A101, a feedstock heating unit A102, a hydrogen heating unit A103, a first hydrotreating reaction unit A104, a first separation unit A105, a second hydrotreating reaction unit A106, a second separation unit A107, a desulfurization unit A108, a membrane separation unit A109, a hydrogen-containing gas unit A110, a first fractionation unit A112, a second fractionation unit A111, a vacuum unit A113, and a catalyst unit A114. The flow chart for this embodiment is shown below. Figure 2 The specific steps are as follows:

[0102] The inferior heavy oil No. 1 feedstock is heated with hydrogen-containing gas and then fed into the first hydrogenation reactor 105 for the first hydrogenation reaction. The first hydrogenation product S8 enters the first high-pressure separator 106 for the first gas-liquid separation, yielding the first gas phase product S9 and the first liquid phase product S10. The first liquid phase product S10 enters the second high-pressure separator 107 for the second gas-liquid separation, yielding the second liquid phase product S12 and the second gas phase product S11. The second liquid phase product S12 enters the first fractionation column 118 for the first fractionation, yielding the first column bottom distillate S33 (boiling point greater than 525℃) and... The first fractionation product S32 (boiling point 120-360℃), the first gaseous product S9, and the second gaseous product S11 are combined and fed into the second hydrogenation reactor 108 for the second hydrogenation reaction. The second hydrogenation product S14 after the reaction enters the third high-pressure separator 109 for the third gas-liquid separation to obtain the third gaseous product S16 and the third liquid product S15. The third gaseous product S16 enters the fourth high-pressure separator 110 for the fourth gas-liquid separation to obtain the fourth gaseous product S17 and the fourth liquid product S18. The third liquid product S15 and the fourth liquid product S18 are sent to the second fractionation tower 111 after being depressurized, where the second fractionation product S19 (light fraction, boiling point 220℃), the third fractionation product S20 (middle fraction, boiling point 360℃), the fourth fractionation product S21 (heavy fraction, boiling point 460℃), the fifth fractionation product S22 (heavy fraction, boiling point 520℃), and the bottom distillate S23 (tail residue, boiling point greater than 540℃) are separated. Part of the bottom distillate of the first tower (first external tail oil S25) is discharged, and the remaining part of the bottom distillate of the first tower (first circulating tower bottom distillate S24) is recycled back to the feed oil tank 101 for the first hydrogenation reaction. The fourth gaseous product S17 enters the desulfurization tower 112 and is purified and desulfurized using a 32% by weight N-methyldiethanolamine (MDEA) solution. The desulfurized high-part gas S28 (hydrogen sulfide content 45ppm) enters the membrane separator 115 and is separated by membrane to obtain hydrogen-rich gas (recycled hydrogen S29) with a hydrogen purity of not less than 93% by volume. The recycled hydrogen S29 is pressurized by the recycled hydrogen compressor 116 and then combined with the new hydrogen S30. The second mixed hydrogen S5 is sent to the hydrogen heater 104, and 5% by volume hydrogen-rich gas is discharged.

[0103] Approximately 15% of the light fraction and 70% of the middle fraction from the first gaseous product separated after the first hydrogenation reactor enter the second hydrogenation reactor. The weight ratio of the bottom distillate S24 from the first circulating tower to the fresh feedstock is 1:1. The weight ratio of the first external tail oil S25 to the fresh feedstock is 0.05:1.

[0104] The catalyst compositions used in the first and second hydrogenation reactors are shown in Table 2. Based on 100 parts by weight of low-quality heavy oil feedstock, the amount of catalyst used in the first hydrogenation reactor is 0.02 parts by weight. Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionation product, the amount of catalyst used in the second hydrogenation reactor is 0.3 parts by weight. The first hydrogenation reactor is a slurry-bed reactor, and the second hydrogenation reactor is a fixed-bed reactor. The reaction conditions for the first and second hydrogenation reactors are shown in Table 3.

[0105] The desulfurization pressure is 16.5 MPa, and the membrane separation pressure is 16.3 MPa. The atmospheric distillation operating conditions in the first fractionation column 118 are 0.15 MPa and 320℃, and the vacuum distillation operating conditions are 10 mmHg and 380℃. The operating conditions of the second fractionation column 111 are 10 mmHg and 385℃. The properties of the products obtained from the second fractionation column are shown in Table 4.

[0106] Example 2

[0107] This embodiment uses a certain type of reduced residue as feedstock, denoted as #2 feedstock, and its properties are shown in Table 1. The process flow for this embodiment is as follows: Figure 3 The difference from Example 1 is that the membrane separator 115 is not provided.

[0108] Approximately 18% of the light fraction and 65% of the middle fraction from the first gaseous product separated after the first hydrogenation reactor enter the second hydrogenation reactor. The weight ratio of the bottom distillate S24 from the first circulating tower to the fresh feedstock is 1.4:1, the weight ratio of the first external tail oil S25 to the fresh feedstock is 0.045:1, and 15% by volume of hydrogen-rich gas is discharged.

[0109] The catalyst compositions used in the first and second hydrogenation reactors are shown in Table 2. Based on 100 parts by weight of low-quality heavy oil feedstock, the amount of catalyst used in the first hydrogenation reactor is 0.015 parts by weight. Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionation product, the amount of catalyst used in the second hydrogenation reactor is 0.32 parts by weight. The first hydrogenation reactor is a slurry-bed reactor, and the second hydrogenation reactor is a fixed-bed reactor. The reaction conditions for the first and second hydrogenation reactors are shown in Table 3.

[0110] The atmospheric distillation operating conditions in the first fractionation column 118 are 0.15 MPa and 340℃, and the vacuum distillation operating conditions are 11 mmHg and 382℃. The operating conditions in the second fractionation column 111 are 9 mmHg and 385℃. The properties of the products obtained from the second fractionation column are shown in Table 4.

[0111] Example 3

[0112] This embodiment uses a mixture of residual oil and deoiled asphalt as feedstock, denoted as feedstock #3, whose properties are shown in Table 1. The process flow for this embodiment is as follows: Figure 4 The difference from Example 1 is that a portion of the first liquid phase product S31 separated by the first high-pressure separator 106 is recycled back to the first hydrogenation reactor 105 via the circulating oil pump 117.

[0113] Approximately 18% of the light distillate and 75% of the middle distillate from the first gaseous product separated after the first hydrogenation reactor enter the second hydrogenation reactor. The weight ratio of the bottom distillate S24 from the first circulating tower to the fresh feedstock is 1.2:1. The weight ratio of the first external tail oil S25 to the fresh feedstock is 0.065:1. The weight ratio of the first liquid product S31 circulating volume to the fresh low-quality heavy oil is 3:1, and 6.0% by volume of hydrogen-rich gas is discharged.

[0114] The catalyst compositions used in the first and second hydrogenation reactors are shown in Table 2. Based on 100 parts by weight of low-quality heavy oil feedstock, the amount of catalyst used in the first hydrogenation reactor is 0.018 parts by weight. Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionation product, the amount of catalyst used in the second hydrogenation reactor is 0.29 parts by weight. The first hydrogenation reactor is a slurry-bed reactor, and the second hydrogenation reactor is a fixed-bed reactor. The reaction conditions for the first and second hydrogenation reactors are shown in Table 3.

[0115] The atmospheric distillation operating conditions in the first fractionation column 118 are 0.15 MPa and 330℃, and the vacuum distillation operating conditions are 10 mmHg and 390℃. The operating conditions of the second fractionation column 111 are 12 mmHg and 370℃. The properties of the products obtained from the second fractionation column are shown in Table 4.

[0116] Example 4

[0117] This embodiment uses a certain heavy oil as the feedstock, denoted as feedstock #4, whose properties are shown in Table 1. The process flow for this embodiment is as follows: Figure 5 The difference from Example 1 is that a portion of the first liquid product S31 separated by the first high-pressure separator 106 is recycled back to the first hydrogenation reactor 105 via the circulating oil pump 117, and a second bottom distillate S23 (boiling point greater than 525°C) is obtained in the second fractionation tower 111. A portion of the second bottom distillate (second external tail oil S35) is discharged, and the remaining portion of the second bottom distillate (second circulating tower bottom distillate S34) is recycled back to the feed oil tank 101 for the first hydrogenation reaction.

[0118] Approximately 20% of the light fraction and 72% of the middle fraction from the first gaseous product separated after the first hydrogenation reactor enter the second hydrogenation reactor. The weight ratio of the bottom distillate S24 from the first circulating tower to fresh feedstock is 1.1:1. The weight ratio of the first external tail oil S25 to fresh feedstock is 0.042:1. The weight ratio of the bottom distillate S34 from the second circulating tower to fresh feedstock is 0.2:1. The weight ratio of the second external tail oil S35 to fresh feedstock is 0.018:1. The weight ratio of the first liquid product S31 circulating volume to fresh low-quality heavy oil is 3.2:1. 5.8% by volume of hydrogen-rich gas is discharged.

[0119] The catalyst compositions used in the first and second hydrogenation reactors are shown in Table 2. Based on 100 parts by weight of low-quality heavy oil feedstock, the amount of catalyst used in the first hydrogenation reactor is 0.021 parts by weight. Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionation product, the amount of catalyst used in the second hydrogenation reactor is 0.32 parts by weight. The first hydrogenation reactor is a slurry-bed reactor, and the second hydrogenation reactor is a fixed-bed reactor. The reaction conditions for the first and second hydrogenation reactors are shown in Table 3.

[0120] The atmospheric distillation operating conditions in the first fractionation column 118 are 0.15 MPa and 330℃, and the vacuum distillation operating conditions are 10 mmHg and 390℃. The operating conditions of the second fractionation column 111 are 14 mmHg and 380℃. The properties of the products obtained from the second fractionation column are shown in Table 4.

[0121] Comparative Example 1

[0122] The method of Example 1 is followed for hydrogenating low-quality heavy oil, except that the second and fourth gas-liquid separations are not performed. Instead, the first gaseous product undergoes a second hydrogenation reaction, and the first and third liquid products are combined and then fractionated to obtain the fractionated product. Approximately 10% of the light fraction and 50% of the middle fraction from the first gaseous product separated after the first hydrogenation reactor enter the second hydrogenation reactor.

[0123] The catalyst composition used in the first and second hydrogenation reactors is shown in Table 2, the reaction conditions are shown in Table 3, and the properties of the products obtained from the second fractionation tower are shown in Table 4.

[0124] Table 1 Properties of Processing Feed Oils

[0125] <![CDATA[density, kg / m 3 > 1052 1068 1072 1024 API level 1.81 1.74 1.95 2.01 C, weight % 84.12 83.79 85.10 84.95 H, weight % 9.98 9.67 9.82 9.22 S, weight % 0.16 5.0 3.8 1.22 N, weight % 0.53 0.34 0.45 0.38 Residual carbon, % by weight 21.3 26.4 5.5 17.6 Asphalt, % by weight 12.8 15.5 19.5 17.8 Ni, μg / g 42.10 86.2 91.1 101.5 V, μg / g 251.4 159.1 521.0 425.4 Final boiling point, ℃ 670 682 692 656

[0126] Table 2 Properties of Hydrogenation Catalysts

[0127]

[0128] Table 3 Hydrogenation reaction process conditions

[0129]

[0130]

[0131] In Table 3, the feed conversion rate = amount of converted feed oil / total amount of feed oil × 100%; the liquid phase product yield = amount of produced liquid phase product / total amount of feed oil × 100%.

[0132] Table 4 Product Properties

[0133]

[0134]

[0135] As shown in Tables 3 and 4, using the method disclosed in this paper to perform hydroconversion on inferior heavy oil is beneficial to improving the conversion rate of inferior heavy oil feedstock and the yield of liquid phase products, thereby obtaining high-quality hydrotreated products. The resulting gasoline fraction has a higher octane number and lower sulfur and nitrogen content, while the diesel fraction has a higher cetane number, lower sulfur and nitrogen content, and a lower pour point.

[0136] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0137] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0138] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A method for hydroconversion of inferior heavy oil, characterized in that, The method includes the following steps: (1) Inferior heavy oil and hydrogen-containing gas are brought into contact with the first hydrogenation catalyst to carry out the first hydrogenation reaction of mild hydrothermal cracking, and the first hydrogenation product is obtained; (2) The first hydrogenation product is subjected to a first gas-liquid separation to obtain a first gas phase product and a first liquid phase product; and at least a portion of the first liquid phase product is subjected to a second gas-liquid separation to obtain a second gas phase product and a second liquid phase product; the conditions for the first gas-liquid separation include: temperature 330-435℃ and pressure 9-26MPa; the conditions for the second gas-liquid separation include: temperature 330-435℃ and pressure 9-26MPa. (3) The second liquid product is subjected to a first fractionation to obtain a first bottom distillate and a first fractionation product, wherein the boiling point of the first fractionation product is in the range of 80-360℃; (4) The first gaseous product, the second gaseous product and the first fractionation product are combined and then contacted with the second hydrogenation catalyst to carry out the second hydrogenation reaction for hydrogenation purification, so as to obtain the second hydrogenation product; (5) The second hydrogenation product is subjected to a third gas-liquid separation to obtain a third gas phase product and a third liquid phase product; and the third gas phase product is subjected to a fourth gas-liquid separation to obtain a fourth gas phase product and a fourth liquid phase product; the conditions for the third gas-liquid separation include: temperature 330-435℃, pressure 9-26MPa; the conditions for the fourth gas-liquid separation include: temperature 330-435℃, pressure 9-26MPa; (6) The third liquid phase product and the fourth liquid phase product are combined and then subjected to a second fractionation to obtain the second bottom distillate and the second fractionation product.

2. The method according to claim 1, wherein, In step (1), the inferior heavy oil is selected from at least one of residual oil, deoiled bitumen, deasphalted oil, coal tar, oil sands, shale oil and crude oil; The properties of the inferior heavy oil include at least one of the following: nickel content of 5-120 μg / g, vanadium content of 20-1200 μg / g, residual carbon value of not less than 5% by weight, asphaltene content of greater than 2.2% by weight, final boiling point of greater than 360℃, and API gravity of less than 25. The active components of the first hydrogenation catalyst include a metal component and a non-metal component, wherein the metal component is selected from at least one group IIIB, IVB, VB, VIB, and VIII metal compounds; and the non-metal component is selected from at least one group VA, IVA, VIA, and VIIA non-metal compounds. Based on 100 parts by weight of the aforementioned inferior heavy oil, the amount of the first hydrogenation catalyst is 0.001-1.0 parts by weight; The conditions for the first hydrogenation reaction include: a temperature of 330-435℃, a hydrogen partial pressure of 8-24 MPa, and a fresh feed volume hourly space velocity of 0.005-1.5 h⁻¹. -1 The hydrogen-to-oil volume ratio is 650-3000.

3. The method according to claim 1, wherein, The inferior heavy oil is selected from heavy oil, which refers to residue oil or distillate oil with a boiling point of 350°C or higher, and the distillate oil is selected from at least one of heavy diesel oil, heavy gas oil, catalytic feedstock, slurry oil and lubricating oil fraction.

4. The method according to claim 2, wherein, The metallic component is selected from at least one of Group IIIB, VB, VIB, and VIII metal compounds; the non-metallic component is selected from at least one of Group VA, IVA, and VIA non-metallic compounds.

5. The method according to claim 1, wherein, The method further includes: returning at least a portion of the first liquid phase product to carry out the first hydrogenation reaction; The weight ratio of the first liquid phase product from the first hydrogenation reaction to the inferior heavy oil is (0.1-6):

1.

6. The method according to claim 1, wherein, In step (3), the operating conditions for the first fractionation include: pressure 0.1-1.0 MPa, temperature 280-400℃; or, the operating conditions for the first fractionation include: vacuum degree 5-40 mmHg, temperature 280-400℃. In step (4), the active component of the second hydrogenation catalyst is selected from at least one of Co-Mo, Ni-Mo, Ni-W, Co-W, Co-Mo-W, and Ni-Mo-W; Based on the total weight of 100 parts by weight of the first gaseous product, the second gaseous product, and the first fractionated product, the amount of the second hydrogenation catalyst is 0.001-1.0 parts by weight. The conditions for the second hydrogenation reaction include: temperature 330-435℃, hydrogen partial pressure 8-22 MPa, and volume hourly space velocity (VHSV) of 0.01-2.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 650-5000.

7. The method according to claim 6, wherein, The active component of the second hydrogenation catalyst is selected from at least one of Co-Mo-W and Ni-Mo-W.

8. The method according to claim 1, wherein, The method further includes: desulfurizing and optionally membrane separating the fourth gaseous product to obtain a hydrogen-rich gas, and returning at least a portion of the hydrogen-rich gas to the first hydrogenation reaction.

9. The method according to claim 1, wherein, In step (6), the operating conditions for the second fractionation include: pressure 0.1-1.0 MPa, temperature 280-360℃; Alternatively, the operating conditions for the second fractionation include: a vacuum of 5-40 mmHg and a temperature of 280-390 °C.

10. The method according to claim 1, wherein, The method further includes: returning a first portion of the first bottom distillate and / or a first portion of the second bottom distillate to perform the first hydrogenation reaction, and discharging a second portion of the first bottom distillate and / or a second portion of the second bottom distillate. The weight ratio of the first bottom distillate and / or the second bottom distillate to the inferior heavy oil is (0.01-4):1; The weight ratio of the first bottom distillate of the second part and / or the second bottom distillate of the second part to the inferior heavy oil is (0.001-0.08):

1.

11. A system for performing the method according to any one of claims 1-10, characterized in that, The system includes a first hydrogenation reaction unit, a first separation unit, a first fractionation unit, a second hydrogenation reaction unit, a second separation unit, and a second fractionation unit connected in sequence. The first separation unit includes a first gas-liquid separator and a second gas-liquid separator connected in sequence. The second separation unit includes a third gas-liquid separator and a fourth gas-liquid separator connected in sequence. The first gas-liquid separator, the second gas-liquid separator, the third gas-liquid separator, and the fourth gas-liquid separator are all high-pressure separators. The liquid phase outlet of the second gas-liquid separator is connected to the first fractionation unit, and the liquid phase outlets of the third gas-liquid separator and the fourth gas-liquid separator are respectively connected to the second fractionation unit.

12. The system according to claim 11, wherein, The system also includes a feedstock oil unit, a feedstock oil heating unit, a hydrogen heating unit, a desulfurization unit, a membrane separation unit, a hydrogen-containing gas unit, a vacuum unit, and a catalyst unit. The feedstock oil unit, the hydrogen-containing gas unit, and the catalyst unit are respectively connected to the feedstock oil heating unit. The hydrogen-containing gas unit is connected to the feedstock oil heating unit through the hydrogen heating unit. The feedstock oil heating unit and the hydrogen heating unit are respectively connected to the first hydrogenation reaction unit to respectively feed the heated material into the first hydrogenation reaction unit for the first hydrogenation reaction. The second separation unit is sequentially connected to the desulfurization unit, the membrane separation unit, and the hydrogen-containing gas unit. The vacuum unit is connected to the first fractionation unit. The first fractionation unit and / or the second fractionation unit are also connected to the first hydrogenation reaction unit.

13. The system according to claim 11, wherein, The reactor used in the first hydrogenation reaction unit is a slurry bed reactor and / or a moving bed reactor.

14. The system according to claim 11, wherein, The reactor used in the second hydrogenation reaction unit is a fixed-bed reactor.

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