Method and system for producing low-sulfur petroleum coke

Abstract

The invention discloses a method and system for producing low-sulfur petroleum coke, and the method comprises the following steps: introducing a residual oil raw material into a residual oil hydrogenation device, and carrying out a hydrodesulfurization reaction to obtain hydrogenated naphtha, hydrogenated diesel oil, hydrogenated wax oil and hydrogenated reduced slag; introducing the hydrogenated wax oil and a part of hydrogenated reduced residues into a catalytic cracking device for catalytic cracking reaction to obtain catalytically cracked gasoline, catalytically cracked diesel oil, catalytically cracked wax oil, oil slurry and propylene-containing LPG (Liquefied Petroleum Gas); the residual hydrogenation reduced residues and catalytic slurry oil filter residues are introduced into a delayed coking device to be subjected to a coking reaction, and coker gas oil and low-sulfur petroleum coke are obtained; and circulating part of catalytic cracking wax oil and oil slurry and part of coker gas oil back to the residual oil hydrogenation device for hydrodesulfurization reaction. The high-sulfur residual oil and the catalytic slurry oil filter residues are taken as raw materials and are directly injected into the coke tower from the top of the coke tower without passing through a raw material system, the low-sulfur petroleum coke is produced at low cost by utilizing the existing device, and the raw material cost is reduced and the benefit is increased by utilizing the catalytic slurry oil filter residues.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry and relates to a method and a system for producing low-sulfur petroleum coke. The low-sulfur petroleum coke can be used as a raw material for producing battery negative electrodes. Background Art

[0002] Petroleum coke is a by-product produced by delayed coking process using residual oil and heavy oil produced in the process of crude oil refining as raw materials. The quality of petroleum coke is greatly affected by the quality of crude oil processed by the refinery, and most of the sulfur and impurities in crude oil are enriched in petroleum coke. According to the industry standard "NB / SH / T 0527-2019 Petroleum Coke (Raw Coke)", petroleum coke with a sulfur content of less than 3% is called low-sulfur coke, which is mainly used to make electrodes in the steel and aluminum industries; petroleum coke with a sulfur content of more than 3% is called high-sulfur coke, which is an economic fuel that can replace thermal coal. It is mainly used as a fuel in the cement, power and steelmaking industries. About 70% of petroleum coke in the world is high-sulfur, fuel-grade petroleum coke. The use of high-sulfur petroleum coke as a highly polluting product is obviously limited, and the rigid demand of the fuel industry will shift to high-quality low-sulfur petroleum coke or alternative fuels. In addition, the demand for new energy electrode materials has increased. Some manufacturers of new energy battery materials use low-sulfur petroleum coke produced by delayed coking units as negative electrode raw materials to produce new energy batteries. After technical communication, manufacturers of new energy battery materials have determined that the quality requirement for low-sulfur petroleum coke is the sulfur content, and the other indicators can be controlled within the internal control range of the device.

[0003] There are many ways to produce low-sulfur petroleum coke. The combination of residue oil hydrogenation and delayed coking is a feasible technical route for producing low-sulfur petroleum coke. The sulfur content of delayed coking raw materials can be reduced by residue oil hydrogenation, so that delayed coking can produce low-sulfur petroleum coke. The processing cost of residue oil hydrogenation is high, and the production cost of low-sulfur petroleum coke needs to be reduced. For example:

[0004] (1) CN 108998060 A discloses that residual oil is mixed with an oxidant, and then subjected to microwave pretreatment and coking treatment to prepare a low-sulfur coke. This method requires corresponding investment and is technically difficult. CN 111363588 A, CN112410066A and CN 112442391 A disclose that residual oil raw materials are subjected to oxidation pretreatment, and the residual oil after oxidation reaction needs to be distilled to remove the diluent solvent. This method is complex in process. The above methods all carry out special treatment of the raw materials.

[0005] (2) CN 112708462 A discloses a combined process of residual oil hydrogenation and delayed coking, wherein a mixture of heavy oil feedstock and circulating diluent oil is fed into a residual oil hydrogenation unit to contact with a hydrogenation catalyst for reaction, and the obtained hydrogenated diesel fraction and / or hydrogenated wax oil fraction is sent to the inlet of the residual oil hydrogenation unit as the circulating diluent oil. The obtained hydrogenated residual oil fraction is fed into a delayed coking unit for coking reaction to obtain a coker gasoline fraction, a coker diesel fraction, a coker wax oil fraction and low-sulfur petroleum coke.

[0006] (3) CN 113563921 A discloses a method and system for producing low-sulfur petroleum coke, which comprises: (1) introducing a residual oil feedstock into a residual oil hydrogenation unit for hydrodesulfurization reaction to obtain hydrotreated wax oil and hydrotreated residue; (2a) introducing the hydrotreated wax oil and a portion of the hydrotreated residue into a catalytic cracking unit for catalytic cracking reaction to obtain catalytic cracking gasoline, catalytic cracking wax oil and oil slurry; (2b) introducing the remaining portion of the hydrotreated residue into a delayed coking unit for coking reaction to obtain coker wax oil and low-sulfur petroleum coke; (3) recycling the catalytic cracking wax oil, oil slurry and coker wax oil back into the residual oil hydrogenation unit for hydrodesulfurization reaction.

[0007] (4) CN 116023995 A discloses a method for producing low-sulfur petroleum coke, comprising: introducing residual oil and additives into a coking furnace for delayed coking, and obtaining low-sulfur petroleum coke and an oil-gas mixture after a coking reaction, wherein the additive is a mixture of a hydrogenation catalyst, a sulfur transfer agent, and an optional hydrogen donor. This method achieves low-sulfur petroleum coke production at a low cost. However, this method has disadvantages such as unstable properties of petroleum coke and difficulty in operation.

[0008] In summary, although the above methods can produce low-sulfur petroleum coke, there are generally shortcomings such as complex production process and high cost. How to reduce production costs while obtaining qualified low-sulfur petroleum coke is an urgent problem that needs to be solved. Summary of the invention

[0009] In order to overcome the problems of complex production process and high cost of low-sulfur petroleum coke, the present invention provides a method and system for producing low-sulfur petroleum coke, which has the advantages of low production cost, simple production method and no need for system modification by changing the source of raw materials and the raw material feeding position.

[0010] The overall technical solution of the present invention is:

[0011] The low-sulfur residue oil obtained by hydrogenation of residue oil is transported to the delayed coking unit through pipelines. The low-sulfur residue oil is mixed with catalytic oil slurry or high-sulfur residue oil for heat exchange, and then mixed with heavy wax oil in the fractionation tower and enters the heating furnace, and finally enters the coke tower for reaction. The catalytic oil slurry filter residue has a high solid content but low cost. As one of the raw materials, it enters the coke tower through the top of the coke tower for reaction, avoiding blockage of pipelines and heat exchangers and erosion and corrosion of equipment, and has no effect on the quality of low-sulfur petroleum coke.

[0012] The circulation ratio is controlled to 0.23-0.5, the bottom temperature of the distillation tower is controlled at 310-325℃, the outlet temperature of the heating furnace is increased to 502±1℃, the evaporation section temperature of the distillation tower is 380-400℃, the heavy wax oil extraction temperature is 310-350℃, the pressure of the distillation tower is increased to 0.09-0.11MPa(g), and the pressure of the coke tower is increased to 0.22MPa(g).

[0013] Specifically, according to a first aspect, the present invention provides a method for producing low-sulfur petroleum coke, the method comprising:

[0014] Step 1, introducing the residual oil raw material into a residual oil hydrogenation device for hydrodesulfurization reaction to obtain hydrogenated naphtha, hydrogenated diesel, hydrogenated wax oil and hydrogenated residue;

[0015] Step 2, introducing the hydrogenated wax oil and a portion of the hydrogenated residue into a catalytic cracking unit for catalytic cracking reaction to obtain catalytic cracking gasoline, catalytic cracking diesel, catalytic cracking wax oil and slurry oil, and LPG containing propylene;

[0016] Step 3, introducing the remaining part of the hydrogenation residue into a delayed coking device for coking reaction, injecting the catalytic oil slurry residue from the top of the coke tower into the coke tower, reacting in the coke tower to obtain coking oil gas and low-sulfur petroleum coke;

[0017] Step 4: recycling at least a portion of the catalytic cracking wax oil and slurry oil obtained in step 2 and at least a portion of the coking wax oil obtained in step 3 back to the residue oil hydrogenation unit for the hydrodesulfurization reaction.

[0018] In step 1 of the present invention, after the hydrodesulfurization reaction is carried out, the reaction products obtained can be separated to obtain gas, hydrogenated naphtha, hydrogenated diesel, hydrogenated wax oil and hydrogenated residue.

[0019] In step 2 of the present invention, after the catalytic cracking reaction, the reaction products obtained can be separated to obtain gas, propylene-rich LPG, catalytic cracking gasoline, catalytic cracking diesel and oil slurry.

[0020] In step 3 of the present invention, after the coking reaction, the reaction products obtained can be separated to obtain gas, coking gasoline, coking diesel, coking wax oil and low-sulfur petroleum coke.

[0021] Preferably, in the delayed coking unit, the proportion of the hydroreduction residue entering the delayed coking unit is controlled so that the catalytic oil slurry ratio of the mixed feed formed by the catalytic cracking oil slurry and a portion of the hydroreduction residue is less than 35% by weight. When it is higher than this interval, the feed proportion of the hydroreduction residue is increased to adjust the solid content of the mixed feed.

[0022] More preferably, in the delayed coking unit, the proportion of the hydroreduced slag entering the delayed coking unit is controlled so that the proportion of the catalytic cracking oil slurry in the mixed feed formed by the catalytic cracking oil slurry and a portion of the hydroreduced slag is 15-35% by weight.

[0023] Preferably, in step 3, the ratio of the catalytic oil slurry filter residue entering the coke drum production is 1.5-3% by weight. When it is higher than this interval, the flow rate of the catalytic oil slurry filter residue entering the coke drum is reduced. When it is lower than this interval, the flow rate of the catalytic oil slurry filter residue entering the coke drum is increased.

[0024] According to a preferred embodiment, in step 2, the delayed coking device contains a heating furnace, a coke tower and a distillation tower, and the conditions in the delayed coking device include: the outlet temperature of the heating furnace is 480°C-510°C, the top outlet temperature of the coke tower is 390-450°C, the pressure of the coke tower is 0.05MPa-0.5MPa, and the circulation ratio is 0.1-0.5.

[0025] Exemplarily, the delayed coking device of the present invention comprises at least one heating furnace, two coke towers and one fractionation tower, and the production is divided into two parts: coking and decoking. The coking is a continuous operation, and the decoking is an intermittent operation.

[0026] Specifically, the present invention also provides a system for producing low-sulfur petroleum coke, the system comprising:

[0027] Residue Hydrotreating Unit,

[0028] Catalytic cracking units, and

[0029] Delayed coking unit;

[0030] The residue oil hydrogenation unit is connected to the catalytic cracking unit through a pipeline, so that the hydrogenated wax oil and a part of the hydrogenated residue obtained from the residue oil hydrogenation unit can enter the catalytic cracking unit;

[0031] The residue oil hydrogenation unit is connected to the delayed coking unit through a pipeline, so that the remaining part of the hydrogenated residue obtained from the residue oil hydrogenation unit can enter the delayed coking unit;

[0032] The catalytic cracking unit and the delayed coking unit are respectively connected to the residue oil hydrogenation unit through pipelines, so that at least part of the catalytic cracking wax oil and slurry oil obtained from the catalytic cracking unit can be circulated back to the residue oil hydrogenation unit, and at least part of the coking wax oil obtained from the delayed coking unit can be circulated back to the residue oil hydrogenation unit.

[0033] The delayed coking unit is connected to the catalytic cracking unit through a pipeline, so that at least part of the catalytic oil slurry residue obtained from the catalytic cracking unit can be recycled back to the delayed coking unit.

[0034] Preferably, the delayed coking device contains a heating furnace, a coke tower and a fractionation tower connected in sequence, so that the raw materials entering the delayed coking device can enter the heating furnace, the coke tower and the fractionation tower in sequence; the raw oil is heated in the heating furnace and then enters the coke tower for coking reaction, and the generated oil enters the fractionation tower.

[0035] The mechanism and beneficial effects of the present invention:

[0036] Compared with the prior art described in (1) in the background technology, the present invention reduces the sulfur content of petroleum coke by directly feeding the catalytic oil slurry filter residue into the coke drum, wherein the raw material is subjected to simple residue oil hydrogenation to reduce the sulfur content to below 0.75 wt %, thereby producing low-sulfur petroleum coke. The method is simpler and more practical.

[0037] Compared with the prior art in (2) described in the background technology, the present invention adds raw materials that do not require hydrogenation and have lower costs, reduces hydrogen consumption, and improves the yield of petroleum coke.

[0038] Compared with the prior art in (3) described in the background technology, the present invention optimizes the raw materials on this basis and directly uses the catalytic oil slurry filter residue as one of the raw materials without the need for hydrogenation treatment, and the catalytic oil slurry filter residue is directly injected into the top of the coke tower, thereby reducing production costs and increasing the yield of petroleum coke.

[0039] The present invention directly transports the catalytic oil slurry filter residue that is difficult to dispose of in the refinery to the coke drum of the delayed coking device, and uses the high temperature in the coke drum to react to generate oil gas and petroleum coke. The catalytic oil slurry filter residue does not pass through the delayed coking raw material heat exchange network, thus avoiding the blockage of pipeline equipment and reducing energy consumption, and converting the catalytic oil slurry filter residue that is difficult to dispose of into high value-added petroleum coke at a low cost.

[0040] In summary, the present invention combines the characteristics of residue oil hydrogenation, catalytic cracking and delayed coking processes, and can use high-sulfur residue oil and catalytic oil slurry filter residue as raw materials, utilize existing equipment of the refinery, and after recombining, produce low-sulfur petroleum coke at low cost, without the need for new equipment, saving investment, and innovatively utilizing catalytic oil slurry filter residue, thereby reducing raw material costs and increasing the benefits of low-sulfur petroleum coke. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention is further described below in conjunction with the accompanying drawings.

[0042] Figure 1 is a schematic diagram of the structure of the system of the present invention, Figure 1 The markings are described as follows:

[0043] 1. Residue oil raw material, 2. Residue oil hydrogenation unit, 3. First gas, 4. Hydrogenated naphtha, 5. Hydrogenated diesel, 7. Catalytic cracking unit, 8. Second gas, 9. Catalytic cracking gasoline, 10. Catalytic cracking diesel, 12. Catalytic oil slurry filter residue, 13. Coking wax oil, 16. Delayed coking unit (including coke tower, fractionation tower), 17. Third gas, 18. Coking gasoline, 19. Coking diesel, 6, 11, 14, 15 are all pipelines.

[0044] Figure 2 A schematic diagram of the structure of the system of the comparative embodiment is shown in FIG. Figure 2 The markings are described as follows:

[0045] 21. Residue oil feedstock, 22. Residue oil hydrogenation unit, 23. First gas, 24. Hydrogenated naphtha, 25. Hydrogenated diesel, 27. Catalytic cracking unit, 28. Second gas, 29. Catalytic cracking gasoline, 210. Catalytic cracking diesel, 212. Coking wax oil, 215. Delayed coking unit (including coke tower and fractionation tower), 216. Third gas, 217. Coking gasoline, 218. Coking diesel. 26, 211, 213 and 214 are all pipelines. DETAILED DESCRIPTION

[0046] Example 1

[0047] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0048] Unless otherwise specified, the pressure described in the present invention is gauge pressure.

[0049] In the present invention, the circulation ratio is expressed by the formula: circulation ratio = sum of the feed amounts of the heating furnace / the amount of raw materials fed into the device - 1.

[0050] The method of the present invention comprises:

[0051] (1) introducing a residual oil feedstock 1 into a residual oil hydrogenation unit 2 for a hydrodesulfurization reaction to obtain a first gas 3, hydrogenated naphtha 4, hydrogenated diesel 5, hydrogenated wax oil and hydrogenated residue;

[0052] (2) introducing the hydrogenated wax oil through pipeline 6 and a portion of the hydrogenated residue through pipeline 14 into a catalytic cracking unit 7 for catalytic cracking reaction to obtain a second gas 8, catalytic cracking gasoline 9, catalytic cracking diesel 10, catalytic cracking wax oil and slurry, and LPG containing propylene;

[0053] (3) introducing the remaining part of the hydrogenated residue into a delayed coking device 16 through a pipeline 15 for a coking reaction, and introducing 2.5 wt % of the catalytic oil slurry residue obtained in step 2-3 into a delayed coking device 16 through a pipeline 12 for a cracking condensation reaction to obtain a third gas 17, coking gasoline 18, coking diesel 19, coking gas oil 13, and low-sulfur petroleum coke (exiting the device from the bottom of the coke tower);

[0054] (4) At least part of the catalytic cracking wax oil and slurry oil obtained in steps 2-3 is recycled through pipeline 11 and at least part of the coking wax oil obtained in step 4 is recycled through pipeline back to the residue oil hydrogenation unit to carry out the hydrodesulfurization reaction.

[0055] The properties of the residual oil raw material 1 used in this example are shown in Table 1.

[0056] The properties of the catalytic oil slurry filter residue 12 used in this embodiment are shown in Table 2.

[0057] The operating conditions, product yields and main product properties of the delayed coking unit in this example are shown in Tables 3 to 5 respectively.

[0058] Table 1

[0059]

[0060] Table 2

[0061] Crude oil number Catalytic oil slurry filter residue 12 <![CDATA[Density (20 °C), kg / m 3 > 1053.7 Sulfur, weight % 0.67 Carbon residue, weight % 6.37 Solid content, weight % 0.004

[0062] Table 3

[0063] Heating furnace outlet temperature, ℃ 502 Coke tower pressure, MPa 0.22 Coke tower top outlet temperature, ℃ 410 Cycle ratio 0.37

[0064] Table 4

[0065]

[0066]

[0067] Table 5

[0068] Coking gas oil properties Sulfur content, weight % 0.58 Petroleum coke properties Sulfur content, weight % 1.24

[0069] It can be seen from Tables 3 to 5 that the sulfur content in the petroleum coke produced by the method of the present invention can be lower than the index requirement of 3.0% (weight %).

[0070] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

[0071] Comparative Example 1

[0072] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0073] Unless otherwise specified, the pressure described in the comparative examples is gauge pressure.

[0074] In this comparative example, the circulation ratio is expressed by the formula: circulation ratio = sum of the feed amounts into the heating furnace / amount of raw materials fed into the device - 1.

[0075] The method of this comparative example comprises:

[0076] (1) introducing a residual oil feedstock 21 into a residual oil hydrogenation unit 22 for a hydrodesulfurization reaction to obtain a first gas 23, hydrogenated naphtha 24, hydrogenated diesel 25, hydrogenated wax oil and hydrogenated residue;

[0077] (2a) introducing the hydrogenated wax oil through pipeline 26 and a portion of the hydrogenated residue through pipeline 213 into a catalytic cracking unit 27 for catalytic cracking reaction to obtain a second gas 28, catalytic cracking gasoline 29, catalytic cracking diesel 210, catalytic cracking wax oil and slurry, and LPG containing propylene;

[0078] (2b) introducing the remaining part of the hydrogenated residue into a delayed coking unit 215 through a pipeline 214 for coking reaction to obtain a third gas 216, coking gasoline 217, coking diesel 218, coking gas oil 212, and low-sulfur petroleum coke (exiting the unit from the bottom of the coke tower);

[0079] (3) At least part of the catalytic cracking wax oil and slurry oil obtained in step (2a) is recycled through pipeline 211 and at least part of the coking wax oil obtained in step (2b) is recycled through a pipeline back to the residue hydrogenation unit for the hydrodesulfurization reaction.

[0080] The properties of the residual oil raw material 1 used in this comparative example are shown in Table 6.

[0081] The operating conditions of the delayed coking unit, product yields and main product properties in this comparative example are shown in Tables 7 to 9 respectively.

[0082] Table 6

[0083]

[0084] Table 7

[0085] Heating furnace outlet temperature, ℃ 502 Coke tower pressure, MPa 0.22 Coke tower top outlet temperature, ℃ 410 Cycle ratio 0.35

[0086] Table 8

[0087] Product Category Product yield, % gas 5.59％ Coking gasoline 14.81％ Coking diesel 35.13％ Coking gas oil 27.34％ Low sulfur coke 17.06％

[0088] Table 9

[0089] Coking gas oil properties Sulfur content, weight % 0.59 Petroleum coke properties Sulfur content, weight % 1.35

[0090] By analyzing and comparing the embodiments and the comparative examples, it is found that the yield of low-sulfur coke in the embodiments is 3.86% by weight higher than that of petroleum coke in the comparative example. By injecting catalytic oil slurry residue at the top of the coke tower, the yield of low-sulfur coke is significantly improved while ensuring the quality of low-sulfur coke, and the production cost of low-sulfur coke is reduced. According to the blending ratio of catalytic oil slurry residue of 2.5% by weight, the production cost of each ton of low-sulfur petroleum coke can be reduced by 190-380 yuan.

Claims

1. A method for producing low-sulfur petroleum coke, characterized in that: The method includes: Step 1, introducing the residual oil raw material into a residual oil hydrogenation device for hydrodesulfurization reaction to obtain hydrogenated naphtha, hydrogenated diesel, hydrogenated wax oil and hydrogenated residue; Step 2, introducing the hydrogenated wax oil and a portion of the hydrogenated residue into a catalytic cracking unit for catalytic cracking reaction to obtain catalytic cracking gasoline, catalytic cracking diesel, catalytic cracking wax oil and slurry oil, and LPG containing propylene; Step 3, introducing the remaining part of the hydrogenation residue and the catalytic oil slurry residue into a delayed coking device for coking reaction to obtain coking wax oil and low-sulfur petroleum coke; the weight percentage of the catalytic oil slurry residue entering the coke tower production is 1.5-3%; Step 4, recycling part of the catalytic cracking wax oil and slurry oil obtained in step 2 and part of the coking wax oil obtained in step 3 back to the residue oil hydrogenation unit to carry out the hydrodesulfurization reaction.

2. The method according to claim 1, characterized in that: In step 1, after the hydrodesulfurization reaction is carried out, the reaction products obtained can be separated to obtain gas, hydrogenated naphtha, hydrogenated diesel, hydrogenated wax oil and hydrogenated residue.

3. The method according to claim 1, characterized in that: In step 2, after the catalytic cracking reaction, the reaction products obtained can be separated to obtain gas, propylene-rich LPG, catalytic cracking gasoline, catalytic cracking diesel and oil slurry.

4. The method according to claim 1, characterized in that: In step 3, after the coking reaction, the reaction products obtained can be separated to obtain gas, coking gasoline, coking diesel, coking wax oil and low-sulfur petroleum coke.

5. The method according to claim 1, characterized in that: In the delayed coking unit, the proportion of the hydroreduced slag entering the delayed coking unit is controlled so that the weight percent of the catalytic cracking slurry in the mixed feed formed by the catalytic cracking slurry and a portion of the hydroreduced slag is less than 35%.

6. The method according to claim 1, characterized in that: In the delayed coking unit, the proportion of the hydroreduced slag entering the delayed coking unit is controlled so that the weight percent of the catalytic cracking slurry in the mixed feed formed by the catalytic cracking slurry and a portion of the hydroreduced slag is 15-35%.

7. The method according to claim 1, characterized in that: In step 3, the delayed coking unit comprises a heating furnace, a coke tower and a fractionating tower.

8. The method according to claim 7, characterized in that: The processing conditions in the delayed coking device include: the outlet temperature of the heating furnace is 480°C-510°C, the outlet temperature of the coke tower top is 390-450°C, the pressure of the coke tower is 0.05-0.5MPa, and the circulation ratio is 0.1-0.

5.

9. A system for producing low-sulfur petroleum coke for realizing the method for producing low-sulfur petroleum coke according to any one of claims 1 to 8, characterized in that: The system contains: Residue hydrotreating unit; Catalytic cracking unit; and Delayed coking unit; The residue oil hydrogenation unit is connected to the catalytic cracking unit through a pipeline, so that the hydrogenated wax oil and a part of the hydrogenated residue obtained from the residue oil hydrogenation unit can enter the catalytic cracking unit; The residue oil hydrogenation unit is connected to the delayed coking unit through a pipeline, so that the remaining part of the hydrogenated residue obtained from the residue oil hydrogenation unit can enter the delayed coking unit; The catalytic cracking unit and the delayed coking unit are respectively connected to the residue oil hydrogenation unit through pipelines, so that part of the catalytic cracking wax oil and slurry oil obtained from the catalytic cracking unit can be circulated back to the residue oil hydrogenation unit, and part of the coking wax oil obtained from the delayed coking unit can be circulated back to the residue oil hydrogenation unit; The delayed coking unit is connected to the catalytic cracking unit through a pipeline, so that part of the catalytic oil slurry residue obtained from the catalytic cracking unit can be recycled back to the delayed coking unit.

10. The system for producing low-sulfur petroleum coke according to claim 9, characterized in that: The delayed coking device contains a heating furnace, a coke tower and a fractionating tower connected in sequence, so that the raw materials entering the delayed coking device can enter the heating furnace, the coke tower and the fractionating tower in sequence; the raw oil enters the coke tower for coking reaction after being heated in the heating furnace, and the generated oil enters the fractionating tower; the catalytic oil slurry filter residue directly enters the coke tower from the top of the coke tower for coking reaction.

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