A method for producing marine fuel oil from atmospheric residue by hydrogenation

Abstract

The application discloses a method for producing marine fuel oil by atmospheric residue hydrogenation, and belongs to the technical field of marine fuel oil production, which comprises the following steps: (1) mixing hydrogen with atmospheric residue as raw oil after the raw oil is heated by a raw oil heater and exchanged with four effluents of a hydrogenation reactor to obtain mixed raw material; (2) heating the mixed raw material to a certain temperature by a mixed raw material heating furnace, then feeding the mixed raw material into a hydrogenation reactor one through a raw material three-way valve to remove solid particles existing in the material; the reaction effluent of the hydrogenation reactor one is sequentially fed into a hydrogenation reactor two and a hydrogenation reactor three to sequentially perform hydrogen demetallization and hydrogen desulfurization reactions; (3) mixing the reaction effluent of the hydrogenation reactor three with recycled oil obtained from a product fractionation system, then feeding the mixture into a hydrogenation reactor four to perform slow cracking reaction; (4) feeding the reaction effluent of the hydrogenation reactor four into a separator system to perform gas-liquid separation, mixing the separated gas phase effluent with new hydrogen to obtain mixed hydrogen, then mixing the mixed hydrogen with the hot raw oil in the step (1), and repeating the steps (2)-(4); and (5) feeding the liquid phase effluent of the separator system into a product fractionation system to perform separation, and obtaining fuel gas, naphtha, marine fuel oil one and marine fuel oil two. The method has the advantages of reducing energy consumption, improving product quality and flexibly adjusting product distribution by improving the hydrogenation process flow of the atmospheric residue.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of marine fuel oil production, and particularly relates to a method for producing marine fuel oil by hydrogenation of atmospheric residue. BACKGROUND

[0002] With the development of the world economy, the international shipping volume continues to grow, and the demand for marine fuel oil is also increasing. At the same time, the quality requirements for marine fuel oil are becoming higher and higher. In particular, the International Maritime Organization (IMO) requires that the sulfur content (mass fraction) of fuel oil used by global ships should not exceed 0.5% from January 1, 2020, which promotes the production process of marine fuel oil to develop towards low sulfur.

[0003] Currently, there are mainly two production processes for low-sulfur marine fuel oil: (1) low-sulfur crude oil is subjected to atmospheric vacuum distillation to obtain residue as heavy components, which is blended with other low-sulfur light components to produce low-sulfur marine fuel oil. Although this method has low production cost, the yield is low and cannot meet the use demand; (2) sulfur in high-sulfur residue is removed by hydrogenation process, and then the low-sulfur marine fuel oil is produced by a distillation system. The latter process has gradually become the main production process for marine fuel oil.

[0004] CN 114644939B discloses a method for producing marine fuel oil by hydrogenation. The method mixes relatively poor residue feedstock with part of the hydrogenated vacuum residue and hydrogen, and then the mixture is introduced into an upflow hydrogenation reactor for hydrogenation reaction. The reaction effluent is mixed with relatively good residue feedstock, and then introduced into a fixed bed hydrogenation unit for reaction. The reaction effluent is subjected to atmospheric distillation and vacuum distillation in sequence, and then part of the hydrogenated vacuum residue and vacuum gas oil are mixed to obtain marine fuel oil products. Although this method can obtain marine fuel oil that meets the requirements of sulfur content and other indicators, a certain amount of high-quality residue is needed as raw material, and the reactor type and distillation process are complex, which is extremely inconvenient to operate.

[0005] CN 115491232B discloses a method for producing ultra-low sulfur marine fuel oil by low-pressure hydrogenation of heavy poor residue. The method combines multiphase flow hydrocracking and fixed bed deep desulfurization online hydrogenation to obtain two blending components for marine fuel oil, and then the two components are blended in a certain proportion to obtain ultra-low sulfur marine fuel oil. However, this method has problems such as large equipment investment and high labor intensity.

[0006] CN 114611943B discloses a method for producing marine fuel oil. The method mixes residual oil raw material with upflow hydrogenation reactor effluent and hydrogen, and then enters a fixed bed hydrogenation unit to perform a hydrofining reaction, obtains hydrogenation product oil, and after constant vacuum fractionation, obtains hydrogenation vacuum residue and hydrogenation vacuum wax oil. Part of the hydrogenation vacuum residue is subjected to mild hydrothermal cracking to obtain marine fuel oil products. The method has high processing cost and operating cost, and poor economy.

[0007] Although the existing process for processing residual oil into marine fuel oil by using hydrogenation technology has been improved in catalyst modification, reactor design, post-treatment technology and the like, there are still problems such as complex process and product blending, and therefore the process technology for hydrogenation of atmospheric residual oil to produce marine fuel oil still needs to be continuously improved to further reduce production cost. SUMMARY

[0008] The present application aims to overcome the problems existing in the prior art process for processing marine fuel oil, and provides a method for hydrogenation of atmospheric residual oil to produce marine fuel oil.

[0009] The purpose of the present application is achieved by the following technical solutions:

[0010] The present application provides a method for hydrogenation of atmospheric residual oil to produce marine fuel oil, comprising the following steps:

[0011] (1) The atmospheric residual oil as raw oil is heated by a raw oil heater and exchanged heat with the four effluents of the hydrogenation reactor, and then mixed with hydrogen to obtain a mixed raw material;

[0012] (2) The mixed raw material is heated to a certain temperature by a mixed raw material heating furnace, and then enters the hydrogenation reactor one through a raw material three-way valve to remove solid particles present in the material; the reaction effluent of the hydrogenation reactor one enters the hydrogenation reactor two and the hydrogenation reactor three in turn to perform hydrogenation demetallization and hydrogenation desulfurization reactions; or

[0013] The mixed raw material is heated to a certain temperature by a mixed raw material heating furnace, and then enters the hydrogenation reactor two through a raw material three-way valve to perform hydrogenation demetallization reaction, and the reaction effluent of the hydrogenation reactor two enters the hydrogenation reactor three to perform hydrogenation desulfurization reaction.

[0014] It should be noted that this step can be switched by the raw material three-way valve according to the actual production situation, so that the mixed raw material does not pass through the hydrogenation reactor one but directly enters the hydrogenation reactor two; during the early stage of device operation, the raw oil enters the hydrogenation reactor one through the raw material three-way valve to remove solid particles; as the running time is prolonged, the pressure drop of the hydrogenation reactor one increases, and when it cannot meet the production requirements, the raw oil is switched by the raw material three-way valve and does not pass through the hydrogenation reactor one but directly enters the hydrogenation reactor two for reaction, thereby prolonging the running period of the entire device.

[0015] (3) The reaction effluent of the third hydrogenation reactor is mixed with the recycle oil obtained from the product fractionation system, and then enters the fourth hydrogenation reactor for slow cracking reaction;

[0016] (4) The reaction effluent of the fourth hydrogenation reactor enters the separator system for gas-liquid separation, and the gaseous phase obtained from the separation (mainly composed of hydrogen) is mixed with fresh hydrogen to obtain mixed hydrogen, which is then mixed with the hot raw oil in step (1) as the mixed raw material in step (2), and steps (2)-(4) are repeated;

[0017] (5) The liquid phase obtained from the separator system enters the product fractionation system for separation to obtain fuel gas, naphtha, marine fuel oil 1 and marine fuel oil 2.

[0018] As a further improvement of the present application, part of the marine fuel oil 2 can be returned to the inlet of the fourth hydrogenation reactor as recycle oil to undergo cracking reaction again according to the actual product demand.

[0019] As a further improvement of the present application, the yield of marine fuel oil 1 and marine fuel oil 2 can be adjusted by adjusting the amount of recycle oil. Specifically, the main products of the present application are marine fuel oil 1 and marine fuel oil 2, and a return line for marine fuel oil 2 is provided, i.e. part of the marine fuel oil 2 is returned to the inlet of the fourth hydrogenation reactor as recycle oil to undergo cracking reaction again, and the product distribution is adjusted by adjusting the amount of recycle oil. According to the production demand, when a large amount of marine fuel oil 2 is required, the amount of recycle oil can be set to zero; when a large amount of marine fuel oil 1 is required, the amount of recycle oil is increased to increase the yield of marine fuel oil 1.

[0020] As a further improvement of the present application, the adjustment of the amount of recycle oil includes:

[0021] The recycle ratio, i.e. the ratio of the amount of recycle oil to the mass flow rate of the product marine fuel oil 2, is set to 0-0.5.

[0022] As a further improvement of the present application, the hydrogenation reactor one, hydrogenation reactor two, hydrogenation reactor three and hydrogenation reactor four are all single-stage fixed bed reactors. The hydrogenation guard, hydrogenation demetallization catalyst, hydrogenation desulfurization catalyst and hydrogenation cracking catalyst are loaded respectively. The hydrogenation guard is in spherical shape, the particle diameter is 2mm-5mm, the active component is Mo and Ni, both in oxidation state, the total content of the active component (in oxidation state) is 2-13%, preferably 5-9%; the hydrogenation demetallization catalyst is in clover shape, the particle outer diameter is 1mm-2mm, the active component is Mo and Ni, both in oxidation state, the total content of the active component (in oxidation state) is 0.5-5%, preferably 1-3%; the hydrogenation desulfurization catalyst is in clover shape, the particle outer diameter is 1mm-2mm, the active component is Mo, Ni and Co, all in oxidation state, the total content of the active component (in oxidation state) is 6-25%, preferably 4-20%; the hydrogenation cracking catalyst is in clover shape, the particle outer diameter is 1mm-2.5mm, the active component is Mo and Ni, both in oxidation state, the total content of the active component (in oxidation state) is 2-12%, preferably 4-9%.

[0023] Further, the hydrogenation reactor one-hydrogenation reactor four are of the same structure, comprising a reactor shell, a support plate is arranged inside the reactor shell, a catalyst bed and a gas-liquid distributor above the catalyst bed are arranged on the support plate, a feed inlet and a reaction effluent outlet are arranged on the upper and lower ends of the reactor shell respectively.

[0024] As a further improvement of the present application, the reaction pressure of the hydrogenation reactor one is 10MPa-32MPa, preferably 14MPa-22MPa, the hydrogen-oil volume ratio is 300:1-3000:1, preferably 500:1-2000:1, the liquid hourly space velocity is 0.05h -1 -4h -1 , preferably 0.1h -1 -2h -1 . The average reaction temperature of the hydrogenation reactor one is 300℃-420℃, the average reaction temperature of the hydrogenation reactor two is 310℃-440℃, the average reaction temperature of the hydrogenation reactor three is 320℃-440℃, and the average reaction temperature of the hydrogenation reactor four is 340℃-480℃.

[0025] As a further improvement of the present application, the main properties of the atmospheric residue are: distillation range >310℃, density (15℃) is 750kg / m 3 -1100kg / m 3 , dynamic viscosity (80℃) is 30mm 2 .s -1 -60mm2 .s -1 The total metal content is 60-200 μg / g, and the sulfur content is 0.15-0.8 wt%.

[0026] As a further improvement of the present application, the metals contained in the atmospheric residue are mainly Fe and Ni, and the proportions of Fe and Ni in the total amount of metals are 30-60% and 20-35%, respectively.

[0027] As a further improvement of the present application, the H2 content in the new hydrogen is ≥99.9 mol%, and the CO content is ≤20 ppm.

[0028] It should be further explained that the technical features corresponding to each of the above options can be combined or replaced with each other to form a new technical solution without conflict.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] (1) The present application uses the high-temperature reaction effluent to exchange heat with the raw oil, effectively recovers the system heat, reduces the heat load of the mixed raw material heating furnace, and thus reduces the energy consumption of the whole system.

[0031] (2) The present application uses the raw material three-way valve to switch the mixed raw material, and when the pressure drop of the hydrogenation reactor one increases due to the blockage as the running time is prolonged, the mixed raw material is switched to directly enter the hydrogenation reactor two, so that the system use period is increased.

[0032] (3) The present application uses the single-stage fixed-bed reactors for the hydrogenation reactors one to four, which are sequentially filled with hydrogenation protective agents, hydrogenation demetallization catalysts, hydrogenation desulfurization catalysts and hydrogenation cracking catalysts, so that the marine fuel oil obtained has good quality and high yield.

[0033] (4) The present application returns part of the relatively heavy marine fuel oil two as a circulating oil to the hydrogenation reactor four inlet to continue the cracking reaction, and by adjusting the amount of the circulating oil, the yield of the marine fuel oil one and the marine fuel oil two is adjusted, so that the product distribution is more flexible.

[0034] (5) The main device of the product fractionation system in the present application is the atmospheric fractionation tower, and no vacuum fractionation tower is set, so that the process is simple; the qualified marine fuel oil product is directly obtained through the product fractionation system, and there is no need for blending, which is easy to operate and reduces the running cost. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0037] Figure 1 The process flow diagram of producing marine fuel oil from atmospheric residue by hydrogenation according to the embodiment of the present application is shown.

[0038] In the figure: 1-hydrogenation reactor one; 2-hydrogenation reactor two; 3-hydrogenation reactor three; 4-hydrogenation reactor four; 5-feed oil heater; 6-mixed feed heater; 7-separator system; 8-product fractionation system; 9-feed three-way valve; 11-feed oil; 12-hot feed oil; 13-mixed feed; 14-hot mixed feed; 15-hydrogenation reactor one feed; 16-hydrogenation reactor one discharge; 17-hydrogenation reactor two feed; 18-hydrogenation reactor two discharge; 19-hydrogenation reactor three discharge; 20-hydrogenation reactor four feed; 21-hydrogenation reactor four discharge; 22-separator feed; 23-separator liquid phase discharge; 24-fuel gas; 25-naphtha; 26-marine fuel oil one; 27-marine fuel oil two; 28-circulating oil; 29-separator gas phase discharge; 30-new hydrogen; 31-mixed hydrogen. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort fall within the scope of protection of the present application.

[0040] The principles and characteristics of the present application will be described below in combination with embodiments. The examples are only used to explain the present application, and are not used to limit the scope of the present application. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments not mentioned by the manufacturer can be obtained by market purchase.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0043] Example 1

[0044] This embodiment provides a method for producing marine fuel oil through atmospheric residue hydrotreating, such as... Figure 1 As shown, the system used in this invention includes a feedstock oil heater 5, a mixed feedstock heater 6, a feedstock three-way valve 9, a hydrogenation reactor 1, a hydrogenation reactor 2, a hydrogenation reactor 3, a hydrogenation reactor 4, a separator system 7, and a product fractionation system 8.

[0045] The main property of atmospheric residue oil used as a feedstock is a density (15℃) of 986 kg / m³. 3 The dynamic viscosity (80℃) is 50 mm. 2 .s -1 The total metal content is 162 μg / g, and the sulfur content is 0.55 wt%.

[0046] The feed oil 11 at 180°C is heated to 310°C by heat exchange with the hydrogenation reactor four effluent 21 in the feed oil heater 5, mixed with hydrogen 31 to obtain the mixed feed 13, and heated to 360°C in the mixed feed heater 6. The hot mixed feed 14 is fed into the hydrogenation reactor one 1 from the top as the hydrogenation reactor one feed 15 via the feed three-way valve 9, and the solid particles in the mixed feed are effectively removed. The hydrogenation reactor one effluent 16 at 368°C is fed into the hydrogenation reactor two 2 from the top, and the metal impurities in the mixed feed are removed by the hydrogenation action of the metal removal catalyst in the hydrogenation reactor two. The hydrogenation reactor two effluent 18 at 377°C from the bottom of the hydrogenation reactor two 2 is fed into the hydrogenation reactor three 3 from the top, and the sulfur components in the mixed feed are removed by the hydrogenation action of the sulfur removal catalyst in the hydrogenation reactor three. The hydrogenation reactor three effluent 19 at 390°C from the bottom of the hydrogenation reactor three is mixed with the recycle oil 28, and fed into the hydrogenation reactor four 4 from the top as the hydrogenation reactor four feed 20 (at 379°C), and the oil product is lightened to a certain extent by the cracking action of the hydrocracking catalyst in the hydrogenation reactor four. The hydrogenation reactor four effluent 21 at 382°C from the bottom of the hydrogenation reactor four is cooled in the feed oil heater 5, and fed into the separator system 7 for gas-liquid separation. The separator gas phase effluent 29 rich in hydrogen is mixed with fresh hydrogen 30 to obtain the mixed hydrogen 31, which is mixed with the hot feed oil 12 and fed into the reactor system. The separator liquid phase effluent 23 is fed into the product fractionation system 8 for product separation, and four products, fuel gas 24, naphtha 25, marine fuel oil one 26 and marine fuel oil two 27, are obtained. The main body device in the product fractionation system 8 is the atmospheric distillation column, and a part of the column bottom effluent is returned to the hydrogenation reactor four as the recycle oil 28, and the rest is taken out as the marine fuel oil two 27. The recycle ratio is 0.5.

[0047] The hydrogenation reactor one has a reaction pressure of 17 MPa, a hydrogen to oil volume ratio of 1200:1, a liquid hourly space velocity of 0.5 h -1 The average reaction temperatures of the hydrogenation reactors one to four are 364°C, 373°C, 384°C and 381°C, respectively.

[0048] The hydrogenation reactor one to four are respectively filled with hydrogen protection catalyst, hydrogen metal removal catalyst, hydrogen sulfur removal catalyst and hydrocracking catalyst. The total content of the active components Mo and Ni (in oxidized state) in the hydrogen protection catalyst is about 6.5%; the total content of the active components Mo and Ni (in oxidized state) in the hydrogen metal removal catalyst is about 2.8%; the total content of the active components Mo, Ni and Co (in oxidized state) in the hydrogen sulfur removal catalyst is about 18.5%; and the total content of the active components Mo and Ni (in oxidized state) in the hydrocracking catalyst is about 7.2%.

[0049] Example 2

[0050] In this example, the recycle ratio is 0, i.e. the bottoms of the main atmospheric distillation column in the product fractionation system 8 are all taken as marine fuel oil two 27. The other operating conditions are the same as in Example 1.

[0051] Example 3

[0052] In this example, the hot mixed feedstock 14 is switched by the feedstock three-way valve 9 to be directly introduced into the hydrogenation reactor two 2 without passing through the hydrogenation reactor one 1. The other operating conditions are the same as in Example 1.

[0053] The following uses one comparative example to illustrate the technical effect of the present application.

[0054] Comparative Example 1

[0055] In this comparative example, the circulating oil is returned to the mixed feedstock furnace inlet, mixed with the mixed feedstock, heated to a certain temperature by the mixed feedstock furnace, and then introduced into the reactor system. The other operating conditions are the same as in Example 1.

[0056] The effects of Examples 1-3 and Comparative Example 1 are counted, as shown in Table 1. In Table 1, the yields of marine fuel oil one and marine fuel oil two are determined based on the feedstock oil.

[0057] Table 1

[0058]

[0059]

[0060] As can be seen from Table 1, the total yield of marine fuel oil in Examples 1-3 is greater than 87%, the sulfur content of marine fuel oil one is between 1800-1860 μg / g, and the sulfur content of marine fuel oil one is between 3200-3290 μg / g, with high yield and obvious desulfurization effect.

[0061] The yield ratio of marine fuel oil one and the yield ratio of marine fuel oil two in Example 1 and Example 2 are 1.66 and 0.66, respectively. It can be seen that adjusting the recycle ratio can effectively adjust the yield of marine fuel oil one and marine fuel oil two. The total yield of marine fuel oil in Example 1 is slightly lower than that in Example 1, which is mainly due to the fact that part of the marine fuel oil two enters the hydrogenation reactor four for cracking reaction again as circulating oil, which increases the yield of fuel gas and naphtha products, and thus the total yield of marine fuel oil is decreased.

[0062] In Example 3, the hydrogenation reactor is removed from the reaction system, and compared with Example 1, although the total yield of marine fuel oil is decreased, qualified products can still be obtained, which shows that when the hydrogenation reactor is blocked and cannot continue to operate with the extension of the running time, the whole device does not need to be stopped, but the raw material can be directly switched to the inlet of the hydrogenation reactor 2, which is beneficial to prolong the running cycle of the whole device.

[0063] In Comparative Example 1, the total yield of marine fuel oil, the quality of marine fuel oil 1 and marine fuel oil 2 are close to those of Example 1. However, due to the increase of the total amount of the mixed raw material into the heating furnace, the heat load of the mixed raw material heating furnace is necessarily increased to reach the specified outlet temperature, thereby causing the energy consumption to increase; at the same time, in order to ensure that the liquid hourly space velocities of the hydrogenation reactors 1-4 remain unchanged, the catalyst loading in the hydrogenation reactors 1-4 is necessarily increased, thereby causing the catalyst usage to increase.

[0064] In summary, by improving the atmospheric residue hydrogenation process, the effects of reducing energy consumption, improving product quality and flexibly adjusting product distribution are achieved.

[0065] Various embodiments of the present application can exist in the form of a range; it should be understood that the description in the form of a range is merely for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application; therefore, it should be considered that all possible sub-ranges and single values within the range have been specifically disclosed.

[0066] In the present application, the orientation words such as "upper" and "lower" are specific to the drawing direction in the drawings. In addition, in the description of the present application, the terms "include", "contain" and the like mean "include but are not limited to". In the present text, the relationship terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. In the present text, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent the cases of A alone, A and B together, and B alone. Wherein A, B can be singular or plural. In the present text, "one or more" means one or more, and "multiple" means two or more. "At least one", "at least one of the following" or the like means any combination of the items, including single item or any combination of multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can represent a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b, c can be single or multiple.

[0067] The above detailed description is a detailed description of the application, and cannot be considered as limiting the specific embodiments of the application to these descriptions. For those skilled in the art, without departing from the concept of the application, a number of simple deductions and substitutions can be made, which should be considered as falling within the protection scope of the application.

Claims

1. A method for producing marine fuel oil by hydrogenation of atmospheric residue, characterized in that, Includes the following steps: (1) The atmospheric residue oil used as feedstock is heated by the feedstock heater and the effluent from the hydrotreating reactor, and then mixed with mixed hydrogen to obtain a mixed feedstock; (2) After the mixed raw materials are heated to a certain temperature in the mixed raw material heater, they enter the first hydrogenation reactor through the raw material three-way valve to remove solid particles present in the material; the reaction effluent of the first hydrogenation reactor then enters the second and third hydrogenation reactors in sequence to carry out hydrogenation demetallization and hydrogenation desulfurization reactions in sequence; or After the mixed raw materials are heated to a certain temperature in the mixed raw material heater, they enter the second hydrogenation reactor through the raw material three-way valve to carry out the hydrogenation demetallization reaction. The reaction effluent of the second hydrogenation reactor enters the third hydrogenation reactor to carry out the hydrogenation desulfurization reaction. (3) The reaction effluent from hydrorea reactor three is mixed with the circulating oil obtained from the product fractionation system and then enters hydrorea reactor four for slow cracking reaction; (4) The effluent from the hydrogenation reactor enters the separator system for gas-liquid separation. The separated gas phase effluent is mixed with fresh hydrogen to obtain mixed hydrogen, which is then mixed with the hot feedstock oil in step (1), and steps (2) to (4) are repeated. (5) The liquid phase of the separator system enters the product fractionation system for separation to obtain fuel gas, naphtha, marine fuel oil I and marine fuel oil II; A portion of the marine fuel oil II is returned to the inlet of the hydrotreating reactor IV as the circulating oil in step (3) for another cracking reaction.

2. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 1, characterized in that, The production of marine fuel oil I and marine fuel oil II is adjusted by changing the amount of circulating oil.

3. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 2, characterized in that, The adjustment of the circulating oil volume includes: The circulation ratio is set to a value greater than 0 and less than or equal to 0.5, which is the ratio of the circulating oil volume to the mass flow rate of the marine fuel oil.

4. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 1, characterized in that, Hydrogenation reactor 1, hydrogenation reactor 2, hydrogenation reactor 3, and hydrogenation reactor 4 are all single-stage fixed-bed reactors.

5. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 1, characterized in that, The reaction pressure of the hydrogenation reactor is 10 MPa to 32 MPa, the hydrogen-to-oil volume ratio is 300:1 to 3000:1, and the liquid hourly space velocity is 0.05 h⁻¹. -1 ~4h -1 .

6. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 1, characterized in that, The average reaction temperature of the first hydrogenation reactor is 300℃~420℃, the average reaction temperature of the second hydrogenation reactor is 310℃~440℃, the average reaction temperature of the third hydrogenation reactor is 320℃~440℃, and the average reaction temperature of the fourth hydrogenation reactor is 340℃~480℃.

7. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 1, characterized in that, The atmospheric residue oil has a distillation range >310℃ and a density of 750~1100 kg / m³ at 15℃. 3 The dynamic viscosity at 80℃ is 30~60 mm. 2 .s -1 The total metal content is 60~200μg / g, and the sulfur content is 0.15~0.8wt%.

8. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 7, characterized in that, The main metals contained in the atmospheric residue oil are Fe and Ni, with Fe and Ni accounting for 30-60% and 20-35% of the total metals, respectively.

9. The method for producing marine fuel oil by hydrogenation of atmospheric residue oil according to claim 1, characterized in that, The new hydrogen contains H2 content ≥ 99.9 mol and CO content ≤ 20 ppm.

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