System for producing clean gasoline from heavy oil

Abstract

A system for producing clean gasoline from heavy oil comprises a first riser reactor, a second riser reactor, a third riser reactor, a fluidized bed reactor and a desulfurizer, the first riser reactor is respectively connected with the second riser reactor and the fluidized bed reactor, the second riser reactor is connected with the desulfurizer, and the third riser reactor is connected with the desulfurizer. The third riser reactor is connected with the fluidized bed reactor; and the fluidized bed reactor is connected with the desulfurization device. According to the invention, in the process of producing the clean gasoline, an additive with relatively high added value is not required to be added for blending, so that the production cost of the clean gasoline is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum refining, and particularly to a system for producing clean gasoline from heavy oil. Background Art

[0002] In recent years, the ownership of automobiles has been increasing continuously, resulting in a continuous growth in the demand for gasoline in China. At the same time, in order to reduce the emissions of harmful substances in automobile exhaust, China has formulated increasingly strict clean gasoline standards. Currently, China implements the National VI (B) standard, requiring that the olefin content in gasoline is not more than 15%, the aromatic hydrocarbon content is not more than 35%, the benzene content is not more than 0.8%, and the sulfur content is not more than 10 mg / L.

[0003] Currently, the process for producing clean gasoline is as follows: heavy oil is desulfurized through MIP catalysis and a desulfurization unit to obtain catalytic cracking gasoline, or heavy oil undergoes catalytic cracking reaction to obtain gasoline, and then through hydrogenation and etherification reactions to obtain catalytic cracking gasoline. The olefin content of the catalytic cracking gasoline obtained by the above two methods is generally 20 v%, that is, the olefin content in the catalytic cracking gasoline is relatively high and does not meet the requirements of the clean gasoline index, and subsequent treatment is required to make the olefin content meet the index requirements. Currently, by adding high-octane additives such as reformed gasoline, alkylated oil, toluene, and xylene to the catalytic cracking gasoline for blending, the blended oil meets the VI (B) standard. However, the use of additives will increase the cost of gasoline blending, and at the same time, the process is too complex. Summary of the Invention

[0004] In order to solve the problem of increasing the cost of gasoline blending by adding additives to catalytic cracking gasoline in the prior art, the present invention provides a system for producing clean gasoline from heavy oil, which does not require adding additives during the process of producing clean gasoline, thus reducing the production cost of clean gasoline.

[0005] To achieve the above object, the specific solution adopted by the present invention is as follows: A system for producing clean gasoline from heavy oil includes a first riser reactor, a second riser reactor, a third riser reactor, a fluidized bed reactor, and a desulfurization device. The first riser reactor is respectively connected to the second riser reactor and the fluidized bed reactor. The second riser reactor is connected to the desulfurization device. The third riser reactor is connected to the fluidized bed reactor. The fluidized bed reactor is connected to the desulfurization device. Heavy oil enters the first riser reactor and the third riser reactor simultaneously, and a first chemical reaction occurs in the first riser reactor to obtain catalytic heavy gasoline and catalytic light gasoline. A third chemical reaction occurs in the third riser reactor to obtain catalytic gasoline. The obtained catalytic heavy gasoline enters the second riser reactor to undergo a second chemical reaction to obtain first cracked gasoline. The obtained catalytic light gasoline and catalytic gasoline enter the fluidized bed reactor to be mixed and undergo a fourth chemical reaction to obtain second cracked gasoline. Then, the first cracked gasoline and the second cracked gasoline enter the desulfurization device to be mixed for a hydrodesulfurization reaction to obtain clean gasoline.

[0006] As an optimized solution of the above system for producing clean gasoline from heavy oil: A first separation unit is provided between the first riser reactor and the second riser reactor. The first separation unit includes a first settler, a first fractionating tower, and a cutting fractionating tower connected in sequence. The first reaction product generated by the first riser reactor is separated by the first settler, fractionated by the first fractionating tower, and cut by the cutting fractionating tower to obtain catalytic light gasoline and catalytic heavy gasoline.

[0007] As another optimized solution of the above system for producing clean gasoline from heavy oil: The cutting fractionating tower is connected to the bottom of the fluidized bed reactor through a light gasoline pipeline and connected to the second riser reactor through a heavy gasoline pipeline. Catalytic light gasoline is sent into the fluidized bed reactor through the light gasoline pipeline, and catalytic heavy gasoline is sent into the second riser reactor through the heavy gasoline pipeline.

[0008] As another optimized solution of the above system for producing clean gasoline from heavy oil: A first regenerator is connected below the first settler. The deactivated catalyst in the first riser reactor enters the first regenerator for regeneration after being separated by the first settler, and the regenerated catalyst enters the first riser reactor.

[0009] As another optimized solution of the above system for producing clean gasoline from heavy oil: A second separation unit is provided between the second riser reactor and the desulfurization device. The second separation unit includes a second settler and a second fractionating tower. The second reaction product generated by the second riser reactor is separated by the second settler and fractionated by the second fractionating tower to obtain first cracked gasoline.

[0010] As another optimization scheme for the above-mentioned system for producing clean gasoline from heavy oil: a first regenerator is arranged below the second settler, and the deactivated catalyst in the second riser reactor is separated in the second settler and then enters the first regenerator for regeneration, and the regenerated catalyst enters the second riser reactor.

[0011] As another optimization scheme for the above-mentioned system for producing clean gasoline from heavy oil: a third separation unit is arranged between the fluidized bed reactor and the desulfurization device, and the third separation unit includes a third settler and a third distillation tower. The fourth reaction product produced by the fluidized bed reactor is sequentially separated in the third settler and fractionated in the third distillation tower to form a second cracked gasoline.

[0012] As another optimization scheme for the above-mentioned system for producing clean gasoline from heavy oil: a second regenerator is arranged below the third settler, and the deactivated catalyst in the fluidized bed reactor is separated in the third settler and then enters the regenerator for regeneration, and the regenerated catalyst enters the third riser reactor.

[0013] As another optimization scheme for the above-mentioned system for producing clean gasoline from heavy oil: the bottom of the fluidized bed reactor has a fourth raw material inlet connected to the third riser reactor and a catalytic light gasoline inlet for the entry of catalytic light gasoline, and the top of the fluidized bed reactor has a fourth outlet connected to the desulfurization device.

[0014] As another optimization scheme for the above-mentioned system for producing clean gasoline from heavy oil: the fluidized bed reactor includes a mixing buffer zone located at its lower part and having a longitudinal cross-section with a larger upper part and a smaller lower part conical structure, and a carry-out control zone located at its upper part and having a longitudinal cross-section with a smaller upper part and a larger lower part conical structure, a mixing stabilization zone with a rectangular longitudinal cross-section is formed between the mixing buffer zone and the carry-out control zone, and the fourth raw material inlet and the catalytic light gasoline inlet are located at the bottom of the mixing buffer zone.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention provides a system for producing clean gasoline from heavy oil. The heavy oil and the catalyst enter the first riser reactor to carry out a first chemical reaction to obtain catalytic heavy gasoline and catalytic light gasoline. The catalytic heavy gasoline and the catalyst enter the second riser reactor to carry out a second chemical reaction to obtain a first cracked gasoline. The heavy oil and the catalyst enter the third riser reactor to carry out a third chemical reaction to obtain catalytic gasoline. The catalytic light gasoline, the catalytic gasoline and the catalyst enter the fluidized bed reactor to mix and carry out a fourth chemical reaction to obtain a second cracked gasoline. The first cracked gasoline and the second cracked gasoline enter the desulfurization device to mix and carry out a hydrodesulfurization reaction to obtain clean gasoline. That is, in the process of producing clean gasoline, it is not necessary to add additives with high added value for blending, which reduces the production cost of clean gasoline and reduces the energy consumption of producing clean gasoline. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the present invention;

[0018] Reference numerals: 1, inlet pipeline II; 2, third riser reactor; 3, fluidized bed reactor; 4, third settler; 5, second regenerator; 6, fractionating tower pipeline III; 7, third fractionating tower; 8, desulfurization pipeline II; 9, cracked diesel pipeline II; 10, slurry pipeline II; 11, inlet pipeline I; 12, first riser reactor; 13, first settler; 14, first regenerator; 15, fractionating tower pipeline I; 16, first fractionating tower; 17, catalytic diesel pipeline I; 18, circulation pipeline; 19, conveying pipeline; 20, cutting pipeline; 21, second riser reactor; 22, second settler; 23, fractionating tower pipeline II; 24, second fractionating tower; 25, cracked diesel pipeline I; 27, desulfurization device; 28, clean gasoline pipeline; 29, cutting fractionating tower; 30, light gasoline pipeline; 31, heavy gasoline pipeline. DETAILED DESCRIPTION OF THE INVENTION

[0019] The technical solutions of the present invention will be further elaborated in detail below in combination with specific embodiments. For parts that are not detailedly described and disclosed in the following embodiments of the present invention, they should all be understood as the prior art known or should be known to those skilled in the art, such as the structures of the first settler, the second settler, the third settler, the first fractionating tower, the second fractionating tower, the third fractionating tower, the cutting fractionating tower, and the desulfurization device, etc.

[0020] Example 1

[0021] A system for producing clean gasoline from heavy oil, comprising a first riser reactor 12, a second riser reactor 21, a third riser reactor 2, a fluidized bed reactor 3 and a desulfurization unit 27. A first chemical reaction occurs in the first riser reactor 12, a second chemical reaction occurs in the second riser reactor 21, a third chemical reaction occurs in the third riser reactor 2, and a fourth chemical reaction takes place in the fluidized bed reactor 3. The first riser reactor 12, the second riser reactor 21 and the third riser reactor 2 are all tubular structures. The first riser reactor 12 is respectively connected to the second riser reactor 21 and the fluidized bed reactor 3, the second riser reactor 21 is connected to the desulfurization unit 27, the third riser reactor 2 is connected to the fluidized bed reactor 3, and the fluidized bed reactor 3 is connected to the desulfurization unit 27. Heavy oil enters the first riser reactor 12 and the third riser reactor 2 simultaneously. In the first riser reactor 12, through the first chemical reaction, catalytic heavy gasoline and catalytic light gasoline can be obtained. In the third riser reactor 2, through the third chemical reaction, catalytic gasoline is obtained. The obtained catalytic heavy gasoline enters the second riser reactor 21 for the second chemical reaction to obtain first cracked gasoline. The obtained catalytic light gasoline and catalytic gasoline enter the fluidized bed reactor 3 to be mixed and undergo the fourth chemical reaction to obtain second cracked gasoline. Then, the first cracked gasoline and the second cracked gasoline enter the desulfurization unit 27 to be mixed for hydrodesulfurization reaction to obtain clean gasoline.

[0022] The bottom of the first riser reactor 12 is connected to an oil inlet pipeline I11 for heavy oil to enter and an inclined pipeline I for the catalyst required for the first chemical reaction to enter. The top of the first riser reactor 12 has a first outlet. The heavy oil enters the first riser reactor 12 and mixes with the catalyst in the first riser reactor 12 to undergo the first chemical reaction to obtain a first reaction product. The first reaction product and the deactivated catalyst form a mixed flow and flow out of the first riser reactor 12 from the first outlet. A first separation unit is arranged between the first riser reactor 12 and the second riser reactor 21. The first separation unit includes a first settler 13, a first fractionating tower 16, and a cutting fractionating tower 29 connected in sequence. The first reaction product generated by the first riser reactor 12 is separated by the first settler 13, fractionated by the first fractionating tower 16, and cut by the cutting fractionating tower 29 to obtain catalytic light gasoline and catalytic heavy gasoline. The bottom of the first settler 13 is connected to a first regenerator 14. The deactivated catalyst in the first riser reactor 12 enters the first regenerator 14 for regeneration after being separated by the first settler 13, and the regenerated catalyst enters the first riser reactor 12. Specifically, an inlet connected to the first outlet is arranged at a position near the top on one side of the first settler 13. The bottom end of the first settler 13 is connected to the top end of the first regenerator 14. The bottom of the first regenerator 14 is connected to the first riser reactor 12 through the inclined pipeline I. The top end of the first settler 13 is connected to the bottom of the first fractionating tower 16 through the fractionating tower pipeline I15. The first fractionating tower 16 is connected to the cutting fractionating tower 29 through the cutting pipeline 20. The cutting fractionating tower 29 is connected to the bottom of the fluidized bed reactor 3 through the light gasoline pipeline 30 and connected to the second riser reactor 21 through the heavy gasoline pipeline 31. That is, the mixed flow formed by the first reaction product and the deactivated catalyst enters the first settler 13 for separation to obtain the first reaction product and the deactivated catalyst. Among them, the first reaction product enters the first fractionating tower 16 through the fractionating tower pipeline I15 for fractionation. The fractionated catalytic gasoline enters the cutting fractionating tower 29 through the cutting pipeline 20. The fractionated catalytic diesel enters the downstream system through the catalytic diesel pipeline I17. A part of the fractionated slurry enters its downstream system through the conveying pipeline 19, and another part of the slurry re-enters the first fractionating tower 16 through the circulation pipeline 18. The catalytic gasoline is fractionated into catalytic light gasoline and catalytic heavy gasoline in the cutting fractionating tower 29. The catalytic light gasoline is sent to the fluidized bed reactor 3 through the light gasoline pipeline 30, and the catalytic heavy gasoline is sent to the second riser reactor 21 through the heavy gasoline pipeline 31. The deactivated catalyst enters the first regenerator 14 for regeneration and then enters the bottom of the first riser reactor 12 through the inclined pipeline I to participate in the first chemical reaction, realizing the recycling of the catalyst.

[0023] A separator is arranged on the cutting pipeline 20. The catalytic gasoline is introduced into the separator to separate out rich gas and sewage and then introduced into the cutting fractionating tower 29.

[0024] A second separation unit is provided between the second riser reactor 21 and the desulfurization unit 27. The second separation unit includes a second settler 22 and a second fractionating tower 24. The second reaction product generated by the second riser reactor 21 is separated by the second settler 22 and fractionated by the second fractionating tower 24 to obtain the first cracked gasoline. A first regenerator 14 is provided below the second settler 22. Specifically, the top outlet of the second riser reactor 21 is connected to a position near the top of one side of the second settler 22. The top of the second settler 22 is connected to the second fractionating tower 24 through the fractionating tower pipeline II 23. The second fractionating tower 24 is connected to the desulfurization unit 27 through the desulfurization pipeline I. The bottom of the second settler 22 is communicated with the first regenerator 14. The bottom of the first regenerator 14 is connected to the bottom of the second riser reactor 21 through the inclined pipeline II. That is, the catalytic heavy gasoline enters the second riser reactor 21 and is mixed with the catalyst in the second riser reactor 21 to undergo a second chemical reaction to obtain a second reaction product. The mixed flow formed by the second reaction product and the deactivated catalyst in the second riser reactor 21 enters the second settler 22 for separation. Among them, the separated second reaction product enters the second fractionating tower 24 through the fractionating tower pipeline II 23 for fractionation. The fractionated first cracked gasoline enters the desulfurization unit 27 through the desulfurization pipeline I. The fractionated first cracked diesel enters the downstream system through the cracked diesel pipeline I 25 in the second fractionating tower 24. And the fractionated slurry enters the circulation pipeline 18 through the slurry pipeline I. The deactivated catalyst enters the first regenerator 14 for regeneration, and the regenerated catalyst enters the second riser reactor 21 to participate in the second chemical reaction.

[0025] A separator is provided on the desulfurization pipeline I. The first cracked gasoline is introduced into the separator to separate out the rich gas and sewage and then introduced into the desulfurization unit 27.

[0026] At the bottom of the third riser reactor 2, there is an oil inlet pipeline II1 for introducing heavy oil and an inclined pipeline II for introducing the catalyst participating in the third and fourth chemical reactions. The top of the third riser reactor 2 is connected to the bottom of the fluidized bed reactor 3. A third separation unit is arranged between the fluidized bed reactor 3 and the desulfurization device 27. The third separation unit includes a third settler 4 and a third fractionating tower 7. The fourth reaction product generated by the fluidized bed reactor 3 is successively separated by the third settler 4 and fractionated by the third fractionating tower 7 to form second cracked gasoline. Below the third settler 4, there is a second regenerator 5. The top outlet of the fluidized bed reactor 3 is connected to the middle of the third settler 4. The top of the third settler 4 is connected to the third fractionating tower 7 through a fractionating tower pipeline III6. The top of the third fractionating tower 7 is connected to the desulfurization device 27 through a desulfurization pipeline II8. The bottom of the third settler 4 is connected to the top of the third regenerator, and the bottom of the third regenerator is connected to the third riser reactor 2 through an inclined pipeline II. That is, heavy oil enters the third riser reactor 2 to undergo a third chemical reaction to obtain a third reaction product. The third reaction product enters the fluidized bed reactor 3 to be mixed with catalytic light gasoline to undergo a fourth chemical reaction to obtain a fourth reaction product. The mixed flow formed by the fourth reaction product and the deactivated catalyst enters the third settler 4 for separation. The separated fourth reaction product enters the third fractionating tower 7 through the fractionating tower pipeline III6 for fractionation. The second cracked gasoline obtained by fractionation enters the desulfurization device 27 through the desulfurization pipeline II8. The slurry obtained by fractionation enters the downstream system through the slurry pipeline II10, and the second cracked diesel obtained by fractionation enters the downstream system through the cracked diesel pipeline II9. The deactivated catalyst enters the regenerator for regeneration, and the regenerated catalyst enters the third riser reactor 2.

[0027] A separator is arranged on the desulfurization pipeline II8. The second cracked gasoline is introduced into the separator to separate out rich gas and sewage and then introduced into the desulfurization device 27. The first cracked gasoline and the second cracked gasoline flow out through the clean gasoline pipeline 28 of the desulfurization device after undergoing hydrodesulfurization reaction.

[0028] Producing clean gasoline using the above system includes the following steps:

[0029] S1. Heavy oil simultaneously enters the first riser reactor 12 and the third riser reactor 2, and undergoes a first chemical reaction in the first riser reactor 12 to obtain catalytic heavy gasoline and catalytic light gasoline, and undergoes a third chemical reaction in the third riser reactor 2 to obtain catalytic gasoline. In this embodiment, the heavy oil is divided into part A and part B. Part A enters the first riser reactor 12 as a raw material through the oil inlet pipeline I11 to undergo a first chemical reaction to obtain a first chemical product. The reaction conditions in the first riser reactor 12 are: the reaction temperature is 480 - 550 °C, the catalyst-oil ratio is 5 - 10, the reaction pressure is 0.1 - 0.4 MPa, the reaction time is 2 - 5 s, and the atomizing steam accounts for 3 - 8 w% of the feed amount. The reaction temperature can be 480 °C, 485 °C, 490 °C, 500 °C, 510 °C, 520 °C, 530 °C, 540 °C or 550 °C. In this embodiment, the reaction temperature is 480 °C; the catalyst-oil ratio can be 5, 6, 7, 8, 9 or 10. In this embodiment, the catalyst-oil ratio is 8; the reaction pressure can be 0.1 MPa, 0.2 MPa, 0.3 MPa or 0.4 MPa. In this embodiment, the reaction pressure is 0.2 MPa; the reaction time can be 2 s, 3 s, 4 s or 5 s. In this embodiment, the reaction time is 3 s; the ratio of the atomizing steam to the feed amount can be 3 w%, 4 w%, 5 w%, 6 w%, 7 w% or 8 w%. In this embodiment, the atomizing steam accounts for 6 w% of the feed amount. The catalyst for the first chemical reaction is a conventional catalytic cracking catalyst. The first chemical product is successively separated by the first settler 13, the first fractionating tower 16 and the cutting fractionating tower 29 to obtain catalytic heavy gasoline and catalytic light gasoline. Part B of the heavy oil enters the third riser reactor 2 as a raw material to undergo a third chemical reaction to obtain a third chemical product containing catalytic gasoline. The reaction conditions in the third riser reactor 2 are: the reaction temperature is 480 - 550 °C, the catalyst-oil ratio is 5 - 10, the reaction pressure is 0.1 - 0.4 MPa, the reaction time is 1 - 2 s, and the atomizing steam accounts for 3 - 8 w% of the feed amount. The reaction temperature can be 480 °C, 490 °C, 500 °C, 510 °C, 520 °C, 530 °C, 540 °C or 550 °C. In this embodiment, the reaction temperature is 490 °C; the catalyst-oil ratio is 5, 6, 7, 8, 9 or 10. In this embodiment, the catalyst-oil ratio is 8; the reaction pressure can be 0.1 MPa, 0.2 MPa, 0.3 MPa or 0.4 MPa. In this embodiment, the reaction pressure can be 0.2 MPa; the reaction time is 1 s, 1.5 s or 2 s. In this embodiment, the reaction time is 1 s; the ratio of the atomizing steam to the feed amount can be 3 w%, 4 w%, 5 w%, 6 w%, 7 w% or 8 w%. In this embodiment, the atomizing steam accounts for 4 w% of the feed amount. The catalyst for the third chemical reaction is a conventional catalytic cracking catalyst.

[0030] S2, The catalytic heavy gasoline enters the second riser reactor 21 as a raw material to carry out a second chemical reaction to obtain a second reaction product. The reaction conditions in the second riser reactor 21 are as follows: the reaction temperature is 550 - 650 °C, the catalyst-to-oil ratio is 8 - 14, the reaction pressure is 0.1 - 0.4 MPa, the reaction time is 2 - 5 s, and the atomizing steam accounts for 1 - 4 w% of the feedstock. Specifically, the reaction temperature can be 550 °C, 560 °C, 570 °C, 580 °C, 590 °C, 600 °C, 610 °C, 620 °C, 630 °C, 640 °C or 650 °C. In this embodiment, the reaction temperature is 600 °C; the catalyst-to-oil ratio is 8, 9, 10, 11, 12, 13 or 14. In this embodiment, the catalyst-to-oil ratio is 12; the reaction pressure can be 0.1 MPa, 0.2 MPa, 0.3 MPa or 0.4 MPa. In this embodiment, the reaction pressure can be 0.2 MPa; the reaction time is 2 s, 3 s, 4 s or 5 s. In this embodiment, the reaction time is 3 s; the ratio of atomizing steam to the feedstock can be 1 w%, 2 w%, 3 w% or 4 w%. In this embodiment, the atomizing steam accounts for 2 w% of the feedstock. The catalyst used in the second chemical reaction is a conventional fluid catalytic cracking catalyst. The second reaction product and the first cracked gasoline are separated by the second settler 22 and the second fractionating tower 24.

[0031] S3, The catalytic gasoline and catalytic light gasoline in the third chemical product enter the fluidized bed reactor 3 and are mixed to carry out a fourth chemical reaction to obtain a fourth reaction product. The reaction conditions in the fluidized bed reactor 3 are as follows: the reaction temperature is 480 - 520 °C, the catalyst-to-oil ratio is 5 - 10, the reaction pressure is 0.1 - 0.4 MPa, the reaction time is 20 - 120 s, and the atomizing steam accounts for 3 - 8 w% of the feedstock. The reaction temperature can be 480 °C, 490 °C, 500 °C, 510 °C or 520 °C. In this embodiment, the reaction temperature is 490 °C; the catalyst-to-oil ratio is 5, 6, 7, 8, 9 or 10. In this embodiment, the catalyst-to-oil ratio is 8; the reaction pressure can be 0.1 MPa, 0.2 MPa, 0.3 MPa or 0.4 MPa. In this embodiment, the reaction pressure can be 0.2 MPa; the reaction time is 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s or 120 s. In this embodiment, the reaction time is 30 s; the ratio of atomizing steam to the feedstock can be 3 w%, 4 w%, 5 w%, 6 w%, 7 w% or 8 w%. In this embodiment, the atomizing steam accounts for 4 w% of the feedstock. Compared with the conventional fluid catalytic cracking reaction, the fourth chemical reaction has a longer reaction time, which is more than ten times that of the conventional fluid catalytic cracking reaction; that is, the catalytic gasoline and catalytic light gasoline in the fourth reaction product are mixed and then cracked, and at the same time, hydrogen transfer reaction and isomerization reaction are carried out to obtain the second cracked gasoline with lower olefin and aromatic hydrocarbon contents.

[0032] S4, the first cracked gasoline obtained in S2 and the second cracked gasoline obtained in S3 are mixed and enter the desulfurization device 27 for desulfurization to obtain clean gasoline. The mixing ratio of the first cracked gasoline and the second cracked gasoline is 1:1.5-2.5. The first cracked gasoline and the second cracked gasoline are mixed to form a mixed cracked gasoline. The mixing ratio of the two affects the olefin content, aromatic content and octane number in the mixed cracked gasoline. Hydrodesulfurization reaction occurs in the desulfurization device 27, the reaction temperature is 380-440°C, the hydrogen partial pressure is 2.0-3.2MPa, and the hydrogen / oil volume ratio is 0.2-0.5. The catalyst used in the hydrodesulfurization reaction is a cobalt-nickel catalyst. That is, clean gasoline can be produced without the need for additives for blending, which reduces the production cost of clean gasoline and reduces energy consumption.

[0033] The above is a basic implementation of the present invention, and further improvements, optimizations and limitations can be made on the above basis to obtain the following embodiments:

[0034] Example 2

[0035] This embodiment is a system improvement scheme for producing clean gasoline from heavy oil based on the embodiment 1. Its main structure is the same as that of the embodiment 1, and the improvement lies in that: the bottom of the fluidized bed reactor 3 has a fourth raw material inlet connected to the third riser reactor 2 and a catalytic light gasoline inlet for catalytic light gasoline to enter, and the top has a fourth outlet connected to the desulfurization device 27. The fluidized bed reactor includes a mixing buffer zone located at its lower part and having a conical structure with a large upper part and a small lower part in the longitudinal section, and a take-out control zone located at its upper part and having a conical structure with a small upper part and a large lower part in the longitudinal section. A mixing stable zone with a rectangular longitudinal section is formed between the mixing buffer zone and the take-out control zone. The second raw material inlet and the catalytic light gasoline inlet are located at the bottom of the mixing buffer zone. The third reaction product, the deactivated catalyst, the fourth raw material and the catalyst participating in the fourth chemical reaction in the third riser reactor 2 enter the mixing buffer zone of the fluidized bed reactor 3 through the fourth raw material inlet. At the same time, the catalytic light gasoline enters the mixing buffer zone through the catalytic light gasoline inlet. After the components are mixed in the mixing buffer zone, they react fully in the mixing stable zone and finally flow out of the fluidized bed reactor 3 through the take-out control zone. The components are mixed more evenly, and the fourth chemical reaction is fully reacted in the fluidized bed reactor 3.

[0036] Application Example 1

[0037] In this application example, the properties of heavy oil are shown in Table 1. The steps for producing clean gasoline are:

[0038] S1. Divide the heavy oil into two parts, A and B. Among them, part A of the heavy oil is used as a raw material to carry out the first chemical reaction at a reaction temperature of 500 °C, a catalyst-oil ratio of 5.5, a reaction pressure of 0.2 MPa, a reaction time of 3 s, and the atomized steam accounting for 3 w% of the feed amount to obtain catalytic light gasoline and catalytic heavy gasoline; part B of the heavy oil is used as a raw material to carry out the third chemical reaction at a reaction temperature of 530 °C, a catalyst-oil ratio of 6, a reaction pressure of 0.2 MPa, a reaction time of 1 s, and the atomized steam accounting for 3 w% of the feed amount to obtain the third reaction product.

[0039] S2. The catalytic heavy gasoline in S1 is used as a raw material to carry out the second chemical reaction at a reaction temperature of 575 °C, a catalyst-oil ratio of 10, a reaction pressure of 0.2 MPa, a reaction time of 3 s, and the atomized steam accounting for 2 w% of the feed amount to obtain the first cracked gasoline.

[0040] S3. The catalytic gasoline in the third reaction product is mixed with the catalytic light gasoline in S1 at a mixing ratio of 1:0.2 to obtain the mixed catalytic gasoline. The mixed catalytic gasoline is used as a raw material to carry out the third chemical reaction at a reaction temperature of 500 °C, a catalyst-oil ratio of 5.5, a reaction pressure of 0.2 MPa, a reaction time of 60 s, and the atomized steam accounting for 3 w% of the feed amount to obtain the second cracked gasoline.

[0041] S4. The first cracked gasoline obtained in S2 and the second cracked gasoline obtained in S3 are mixed in a ratio of 1:2 and enter the desulfurization unit 27 to carry out the hydrodesulfurization reaction at a reaction temperature of 400 °C, a hydrogen partial pressure of 2.0 MPa, and a hydrogen / oil volume ratio of 0.2. Finally, clean gasoline is obtained. The properties of the clean gasoline are shown in Table 3. The olefin content in the clean gasoline is 13.8 v%, the aromatic hydrocarbon content is 34.2 v%, and the octane number is 94.1.

[0042] Application Example 2

[0043] In this application example, the properties of the heavy oil are shown in Table 1. The steps and reaction conditions for producing clean gasoline are the same as those in Application Example 1. The properties of the obtained clean gasoline are shown in Table 3. The olefin content in the clean gasoline is 14.1 v%, the aromatic hydrocarbon content is 34.3 v%, and the octane number is 94.3.

[0044] Application Example 3

[0045] In this application example, the properties of the heavy oil are shown in Table 1. The steps and reaction conditions for producing clean gasoline are the same as those in Application Example 1. The properties of the obtained clean gasoline are shown in Table 3. The olefin content in the clean gasoline is 14.3 v%, the aromatic hydrocarbon content is 34.6 v%, and the octane number is 94.4.

[0046] Comparative Example 1

[0047] In this comparative example, the properties of the heavy oil used are the same as those of the heavy oil used in Application Example 1. The steps for producing clean gasoline in this comparative example are as follows: The heavy oil undergoes a third chemical reaction in the third riser reactor, and then passes through a fluidized bed reactor to obtain catalytic gasoline. The catalytic gasoline undergoes hydrodesulfurization to obtain a gasoline product. The main operating conditions are shown in Table 2, and the properties of the obtained gasoline are shown in Table 3. The olefin content of the gasoline product does not meet the national VI (B) gasoline standard, and reformate needs to be added for blending to obtain clean gasoline that meets the national VI (B) gasoline standard. The energy consumption during the production of clean gasoline is 37.65 kgEO / t.

[0048] Comparative Example 2

[0049] In this comparative example, the properties of the heavy oil used are the same as those of the heavy oil used in Application Example 1. The steps for producing clean gasoline in this comparative example are as follows: The heavy oil undergoes a catalytic cracking reaction to obtain catalytic gasoline. The catalytic gasoline undergoes hydrogenation and etherification to obtain a gasoline product. The main operating conditions are as shown in the table, and the properties of the obtained gasoline product are shown in Table 3. The olefin content of the gasoline product does not meet the national VI (B) gasoline standard, and reformate needs to be added for blending to obtain clean gasoline that meets the national VI (B) gasoline standard. The energy consumption during the production of clean gasoline is 38.12 kgEO / t.

[0050] Comparative Example 3

[0051] In this comparative example, the properties and weight of the heavy oil used are the same as those of the heavy oil used in Application Example 1. The steps for producing clean gasoline in this comparative example are as follows: The heavy oil undergoes a first chemical reaction to obtain catalytic gasoline. The catalytic gasoline undergoes a second chemical reaction to obtain cracked gasoline. The cracked gasoline undergoes a hydrodesulfurization reaction to obtain a gasoline product. The main operating conditions are shown in Table 2, and the properties of the obtained gasoline product are shown in Table 3. The aromatic content in the gasoline product does not meet the national VI (B) gasoline standard, and alkylate needs to be added for blending to obtain clean gasoline that meets the national VI (B) gasoline standard. The energy consumption during the production of clean gasoline is 39.83 kgEO / t.

[0052] Table 1 Properties of Heavy Oil

[0053] Table 2 Main Operating Conditions

[0054] Table 3 Properties of Clean Gasoline

[0055] Comparing Comparative Example 1 with Application Example 1, the properties of the heavy oil used in both are the same. However, the olefin content of the gasoline product obtained in Comparative Example 1 does not meet the National VI (B) gasoline standard and needs to be blended with reformed gasoline to meet the National VI (B) gasoline standard. At the same time, the energy consumption in the process of producing clean gasoline in Comparative Example 1 is higher than that in Application Example 1 for producing clean gasoline.

[0056] Comparing Comparative Example 2 with Application Example 1, the properties of the heavy oil used in both are the same. However, the olefin content of the gasoline product obtained in Comparative Example 2 does not meet the National VI (B) gasoline standard and needs to be blended with reformed gasoline to meet the National VI (B) gasoline standard. At the same time, the energy consumption in the process of producing clean gasoline in Comparative Example 2 is higher than that in Application Example 1 for producing clean gasoline.

[0057] Comparing Comparative Example 3 with the Application Example, the properties of the heavy oil used in both are the same. The aromatic hydrocarbon content of the gasoline product in Comparative Example 3 does not meet the National VI (B) gasoline standard and needs to be blended with alkylated oil to obtain clean gasoline that meets the National VI (B) gasoline standard. At the same time, the energy consumption of producing clean gasoline in Comparative Example 3 is higher than that in Application Example 1.

[0058] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for producing clean gasoline from heavy oil, comprising a first riser reactor (12), a second riser reactor (21), a third riser reactor (2), a fluidized bed reactor (3) and a desulfurization device (27), characterized in that: The first riser reactor (12) is respectively connected to the second riser reactor (21) and the fluidized bed reactor (3). The second riser reactor (21) is connected to the desulfurization unit (27). The third riser reactor (2) is connected to the fluidized bed reactor (3). The fluidized bed reactor (3) is connected to the desulfurization unit (27). Heavy oil enters the first riser reactor (12) and the third riser reactor (2) simultaneously. In the first riser reactor (12), a first chemical reaction occurs to obtain catalytic heavy gasoline and catalytic light gasoline. In the third riser reactor (2), a third chemical reaction occurs to obtain catalytic gasoline. The obtained catalytic heavy gasoline enters the second riser reactor (21) for a second chemical reaction to obtain first cracked gasoline. The obtained catalytic light gasoline and catalytic gasoline enter the fluidized bed reactor (3) to be mixed and undergo a fourth chemical reaction to obtain second cracked gasoline. Then, the first cracked gasoline and the second cracked gasoline enter the desulfurization unit (27) to be mixed for a hydrodesulfurization reaction to obtain clean gasoline.

2. The system for producing clean gasoline from heavy oil according to claim 1, characterized in that: A first separation unit is provided between the first riser reactor (12) and the second riser reactor (21). The first separation unit includes a first settler (13), a first fractionating tower (16), and a cutting fractionating tower (29) connected in sequence. The first reaction product generated by the first riser reactor (12) is separated by the first settler (13), fractionated by the first fractionating tower (16), and cut by the cutting fractionating tower (29) to obtain catalytic light gasoline and catalytic heavy gasoline.

3. The system for producing clean gasoline from heavy oil according to claim 2, wherein: The cutting fractionating tower (29) is connected to the bottom of the fluidized bed reactor (3) through a light gasoline pipeline (30) and is connected to the second riser reactor (21) through a heavy gasoline pipeline (31). The catalytic light gasoline is sent into the fluidized bed reactor (3) through the light gasoline pipeline (30), and the catalytic heavy gasoline is sent into the second riser reactor (21) through the heavy gasoline pipeline (31).

4. The system for producing clean gasoline from heavy oil according to claim 2, wherein: A first regenerator (14) is connected below the first settler (13). The deactivated catalyst in the first riser reactor (12) enters the first regenerator (14) for regeneration after being separated by the first settler (13), and the regenerated catalyst enters the first riser reactor (12).

5. The system for producing clean gasoline from heavy oil according to claim 1, characterized in that: A second separation unit is provided between the second riser reactor (21) and the desulfurization unit (27). The second separation unit includes a second settler (22) and a second fractionating tower (24). The second reaction product generated by the second riser reactor (21) is separated by the second settler (22) and fractionated by the second fractionating tower (24) to obtain first cracked gasoline.

6. The system for producing clean gasoline from heavy oil according to claim 5, wherein: A first regenerator (14) is provided below the second settler (22). The deactivated catalyst in the second riser reactor (21) enters the first regenerator (14) for regeneration after being separated by the second settler (22), and the regenerated catalyst enters the second riser reactor (21).

7. The system for producing clean gasoline from heavy oil according to claim 1, wherein: A third separation unit is arranged between the fluidized bed reactor (3) and the desulfurization device (27), and the third separation unit comprises a third settler (4) and a third fractionation tower (7). The fourth reaction product produced by the fluidized bed reactor (3) is sequentially separated in the third settler (4) and fractionated in the third fractionation tower (7) to form a second cracked gasoline.

8. The system for producing clean gasoline from heavy oil according to claim 7, characterized in that: A second regenerator (5) is arranged below the third settler (4). The deactivated catalyst in the fluidized bed reactor (3) is separated in the third settler (4) and then enters the regenerator for regeneration. The regenerated catalyst enters the third riser reactor (2).

9. The system for producing clean gasoline from heavy oil according to claim 1, characterized in that: The bottom of the fluidized bed reactor (3) has a fourth raw material inlet connected to the third riser reactor (2) and a catalytic light gasoline inlet for catalytic light gasoline to enter, and the top of the fluidized bed reactor (3) has a fourth outlet connected to the desulfurization device (27).

10. A system for producing clean gasoline from heavy oil as described in claim 9, characterized in that: The fluidized bed reactor (3) comprises a mixing buffer zone located at its lower part and having a longitudinal cross-section with a larger upper part and a smaller lower part conical structure, and a carry-out control zone located at its upper part and having a longitudinal cross-section with a smaller upper part and a larger lower part conical structure, a mixing stabilization zone with a rectangular longitudinal cross-section is formed between the mixing buffer zone and the carry-out control zone, and a fourth raw material inlet and a catalytic light gasoline inlet are located at the bottom of the mixing buffer zone.

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