A system and method for catalytic conversion of light hydrocarbon oils to produce lower carbon olefins and aromatics

Abstract

The present disclosure relates to a system and method for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of light hydrocarbon oil, which independently sets the device for cracking reaction and the device for catalyst regeneration, and can improve the adaptability and safety of the system. The full-closed anti-coking cyclone assembly or the coarse-rotation top-rotation closed direct-connection assembly arranged in the reaction settler can reduce the risk of coking of high-temperature oil gas in the reaction settler, and can reduce the risk of secondary cracking, thereby improving the yield of the target product. In addition, the oil gas quencher arranged in the system of the present disclosure can quickly reduce the temperature of the reaction oil gas at the outlet of the reactor, avoid the safety hazards caused by excessive thermal cracking and condensation coking of the reaction oil gas in the large oil gas pipeline at the outlet of the reactor, and effectively utilize the heat in the high-temperature reaction oil gas.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of petroleum chemical industry, in particular, to a system and method for catalytic conversion of light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons. BACKGROUND

[0002] Low-carbon olefins (ethylene, propylene) and low-carbon aromatic hydrocarbons (BTX) are important basic organic raw materials for petroleum chemical industry, and play a crucial role in the petrochemical industry.

[0003] Ethylene is a basic chemical raw material for the synthesis of fibers, synthetic rubber, synthetic plastics (polyethylene and polyvinyl chloride), synthetic ethanol (alcohol), and is also used to manufacture vinyl chloride, styrene, oxirane, acetic acid, acetaldehyde and explosives, etc. Propylene, as an important basic raw material for petroleum chemical industry next to ethylene, is widely used to produce polypropylene, acrylonitrile, isopropanol, phenol and acetone, butanol and octanol, acrylic acid and its esters, and to produce epoxypropane and propylene glycol, epichlorohydrin and synthetic glycerol, etc. Aromatic hydrocarbons are an important organic chemical basic raw material, among which benzene, toluene and xylene (including o-xylene, m-xylene and p-xylene) are widely used, and their end products are used in the fields of synthetic resins, synthetic fibers, synthetic rubber, coatings, dyes and pharmaceuticals, etc.

[0004] In the production technology of low-carbon olefins by cracking of hydrocarbons, the tubular furnace thermal cracking method is one of the main methods for the production of ethylene and propylene. With the increasing demand for propylene derivatives, the production of propylene obtained by the thermal cracking method cannot meet the growing demand of the market for propylene. Therefore, improving the yield of propylene / ethylene has become a hot issue. In addition, the steam cracking technology also has a series of problems such as high energy consumption, high carbon emission, high equipment investment, narrow selection range of raw materials, and serious environmental pollution, and the application range of the steam cracking technology is more and more limited.

[0005] In recent years, more and more attention has been paid to other new technologies for producing low-carbon olefins and low-carbon aromatic hydrocarbons, and the technology for producing low-carbon olefins and low-carbon aromatic hydrocarbons by catalytic cracking is one of the most widely used technologies. For example, the prior art proposes a method for converting petroleum hydrocarbon raw materials into low-carbon olefins through a catalytic cracking (cracking) reaction process, but it still cannot solve the problems of insufficient heat of the reaction-regeneration system, safety hazards caused by reactor wear, high-temperature crushing and deactivation of the catalyst, etc. in the catalytic conversion process of light hydrocarbon oil, and does not involve a scheme for recovering high-value low-carbon aromatic hydrocarbons and improving the yield of low-carbon aromatic hydrocarbons. SUMMARY

[0006] The purpose of the present disclosure is to provide a system and method for catalytic conversion of light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons, in order to solve the problems of insufficient heat of the reaction-regeneration system, safety hazards caused by reactor wear, high-temperature crushing and deactivation of the catalyst, etc. in the prior art.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present disclosure provides a system for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of light hydrocarbon oil, which comprises a riser reactor arranged coaxially, a reaction product purification and separation unit, and an oil gas quencher; the oil gas quencher is arranged at the top of the reaction product purification and separation unit; the reaction product purification and separation unit comprises a stripping section and a reaction settler from bottom to top, and the stripping section and the reaction settler are separated by a sealing cover plate; a fully-closed anti-coking cyclone assembly is arranged in the reaction settler; the fully-closed anti-coking cyclone assembly comprises a cyclone quick separation head, a closed cover, and a reaction cyclone separator; the closed cover is a sealing cylinder arranged at the upper part of the stripping section; the outlet at the upper part of the sealing cylinder is communicated with the inlet of the reaction cyclone separator through a flow guide cylinder; the lower part of the sealing cylinder extends downward into the stripping section through the sealing cover plate, and the lower part of the closed cover is provided with a notch to communicate the inside and outside of the closed cover only through the notch; the upper part of the riser reactor is embedded inside the reaction product purification and separation unit, and the top of the riser reactor extends into the sealing cylinder, and the cyclone quick separation head is arranged at the top outlet of the riser reactor; alternatively, a coarse cyclone top cyclone sealing direct connection assembly is arranged in the reaction settler; the coarse cyclone top cyclone sealing direct connection assembly comprises a coarse cyclone, an oil gas collecting pipe, an oil gas sealing guide pipe, and a reaction cyclone separator; the top outlet of the riser reactor is communicated with the inside of the oil gas collecting pipe through the coarse cyclone; the gas outlet of the oil gas collecting pipe is communicated with the inlet of the reaction cyclone separator; the bottom inlet of the oil gas sealing guide pipe extends downward into the gas phase space at the upper part of the stripping section through the sealing cover plate; the gas phase space at the lower part of the sealing cover plate is communicated with the oil gas collecting pipe through the oil gas sealing guide pipe; the stripping section comprises a spent catalyst outlet and an optional reaction circulating catalyst outlet; the riser reactor comprises a regenerated catalyst inlet and an optional reaction circulating catalyst inlet; the spent catalyst outlet of the stripping section is communicated with the inlet of a catalyst regeneration device through a spent catalyst inclined pipe; the regenerated catalyst inlet of the riser reactor is communicated with the outlet of the catalyst regeneration device through a regenerated catalyst inclined pipe; the reaction circulating catalyst outlet of the stripping section is communicated with the reaction circulating catalyst inlet of the riser reactor through a reaction circulating catalyst inclined pipe.

[0008] Optionally, the riser reactor comprises a pre-lifting section, a variable-diameter section and a reaction section connected in sequence from bottom to top; the pre-lifting section and the reaction section are both equal-diameter cylindrical; the ratio of the inlet diameter of the reaction section to the diameter of the pre-lifting section is 1-5; the length ratio of the pre-lifting section, the variable-diameter section and the reaction section is 1:(0.05-0.5):(1-10); the pre-lifting section is provided with a pre-lifting medium nozzle, a regenerated catalyst inlet and a back-mixing medium nozzle; the pre-lifting medium nozzle is used to communicate with a pre-lifting medium source, the back-mixing medium nozzle is used to communicate with a back-mixing medium source, and the regenerated catalyst inlet communicates with one end of the regenerated inclined pipe; the variable-diameter section is provided with a raw material nozzle used to communicate with a light hydrocarbon oil raw material source; and the reaction section is provided with a dilution steam nozzle used to communicate with a dilution steam source.

[0009] Optionally, the reaction settler is further provided with a reaction gas collection chamber and an anti-coking steam ring located below the reaction gas collection chamber; the outlet of the reaction gas collection chamber communicates with the top outlet of the reaction settler; the inlet of the anti-coking steam ring is used to communicate with an anti-coking steam source; the upper surface and / or the lower surface of the anti-coking steam ring is provided with steam injection holes; the reaction cyclone separator is at least one stage, preferably two stages; the outlet of the draft tube communicates with the inlet of the first-stage reaction cyclone separator; the gas outlet of the last-stage reaction cyclone separator communicates with the inlet of the reaction gas collection chamber; the catalyst outlet of the reaction cyclone separator extends downward through the sealing cover plate to the gas phase space formed by the outer wall of the closed cover and the sealing cover plate by means of a leg; or, the gas outlet of the oil gas collection pipe communicates with the inlet of the first-stage reaction cyclone separator; the gas outlet of the last-stage reaction cyclone separator communicates with the inlet of the reaction gas collection chamber; the catalyst outlet of the coarse cyclone, the outlet of the oil gas closed guide pipe and the catalyst outlet of the reaction cyclone separator extend downward through the sealing cover plate to the gas phase space below the sealing cover plate by means of a leg.

[0010] Optionally, the stripping section comprises stripping section internals, at least one set of stripping steam rings and loosening steam rings; the stripping section internals comprise one or more of herringbone baffles, ring baffles, disc umbrella baffles, packings and grates; the stripping steam rings are located in the middle and / or lower part of the stripping section; the loosening steam rings are located in the bottom of the stripping section; the upper surface and / or the lower surface of the stripping steam rings and the loosening steam rings are provided with steam wear-resistant nozzles.

[0011] Optionally, the oil-gas quencher comprises an oil-gas distributor, a quencher baffle, a quenching medium distributor and a stirring steam ring; the oil-gas distributor is located at the bottom of the oil-gas quencher and the top outlet of the reaction settler is communicated with the inlet of the oil-gas distributor; the quencher baffle is located above the oil-gas distributor; the quencher baffle has 1-20 layers; the quenching medium distributor is located at the upper part of the quencher baffle; the lower surface of the quenching medium distributor is provided with injection holes, and the airflow direction of the injection holes of the quenching medium distributor is vertically downward and / or obliquely downward; the stirring steam ring is located at the lower part of the oil-gas quencher; the upper surface of the stirring steam ring is provided with injection holes, and the airflow direction of the injection holes of the stirring steam ring is vertically upward and / or obliquely upward.

[0012] The second aspect of the present disclosure adopts the system of the first aspect of the present disclosure to produce low-carbon olefins and aromatic hydrocarbons by catalytic conversion of light hydrocarbon oil, which comprises: making the light hydrocarbon oil feedstock enter the riser reactor to contact with the regenerated catalyst to perform cracking reaction, to obtain reaction material containing cracking reaction products and spent catalyst; making the reaction material enter the full-closed anti-coking cyclone assembly or the coarse-rotation top-rotation closed direct connection assembly in the reaction settler through the outlet of the riser reactor to perform separation treatment, to obtain high-temperature reaction oil gas and spent catalyst material; making the high-temperature reaction oil gas enter the oil-gas quencher to exchange heat with the quenching medium, to obtain low-temperature reaction oil gas; further separating the low-temperature reaction oil to obtain low-carbon olefins and low-carbon aromatic hydrocarbons; making the spent catalyst material enter the stripping section to contact with stripping steam to perform stripping treatment, to obtain spent catalyst; making the spent catalyst enter the regeneration device as spent agent through the spent catalyst inclined pipe; optionally, making part of the spent catalyst return to the riser reactor as circulating catalyst through the reaction circulating inclined pipe.

[0013] Optionally, the light hydrocarbon oil feedstock is selected from one or more of light distillate with a distillation range of 20-300℃, preferably catalytic cracking gasoline, catalytic cracking gasoline, straight-run naphtha, coking naphtha, thermal cracking naphtha, thermal cracking naphtha, hydrogenated naphtha, reforming raffinate, straight-run kerosene and hydrogenated kerosene; the regenerated catalyst comprises zeolite, inorganic oxide and clay; the content of zeolite is 0.5-90% by weight, the content of inorganic oxide is 1-99% by weight, and the content of clay is 0-80% by weight, based on the total weight of the regenerated catalyst; the zeolite comprises mesoporous zeolite, medium-pore zeolite and optional macroporous zeolite; the content of mesoporous zeolite is 10-90% by weight, the content of medium-pore zeolite is 10-90% by weight, and the content of macroporous zeolite is 0-50% by weight, based on the total weight of the zeolite; the quenching medium is selected from one or more of heavy oil products with an initial boiling point of above 300℃, preferably cracking heavy oil, catalytic cracking slurry, catalytic cracking slurry, coking slurry, atmospheric residue and vacuum residue.

[0014] Optionally, the reaction conditions of the cracking reaction include: a preheating temperature of 40-600℃, a reaction temperature of 400-900℃, a reaction pressure of 0.01-1.0 MPa(g), a reaction time of 0.1-30 s, a mass flow rate ratio of the regenerated catalyst to the light hydrocarbon oil feedstock of 1-100, and a mass flow rate ratio of water vapor to the light hydrocarbon oil feedstock of 0.05-2; the operating conditions of the stripping section include: an average gas superficial linear velocity of 0.05-1 m / s, and an average catalyst residence time of 0.5-10 min; and the operating conditions of the oil gas quencher include: an outlet reaction oil gas temperature of 200-550℃, a bottom liquid temperature of 200-500℃, and a bottom liquid residence time of 0-15 min.

[0015] Optionally, the method further includes: subjecting the reaction material to a first separation by a cyclone quick separation head at the outlet of the riser reactor to obtain a coarsely separated oil gas and a first spent catalyst; subjecting the first spent catalyst to downward flow in the internal space of the closed cover and flow into the stripping section; subjecting the coarsely separated oil gas to upward flow in the internal space of the closed cover and pass through the draft tube into a reaction cyclone separator to undergo a second separation to obtain the high-temperature reaction oil gas and a second spent catalyst; and subjecting the high-temperature reaction oil gas to enter an oil gas quencher from the gas phase outlet of the reaction cyclone separator, and subjecting the second spent catalyst to enter a gas phase space formed by the outer wall of the closed cover and the sealing cover plate from the catalyst outlet of the reaction cyclone separator, and finally enter the stripping section through the slot; or the method further includes: subjecting the reaction material to a first separation by a coarse cyclone to obtain a coarsely separated oil gas and a first spent catalyst; subjecting the coarsely separated oil gas to enter a reaction cyclone separator to undergo a second separation to obtain the high-temperature reaction oil gas and the second spent catalyst; subjecting the high-temperature reaction oil gas to enter an oil gas quencher from the gas phase outlet of the reaction cyclone separator; and subjecting the first spent catalyst flowing out from the catalyst outlet of the coarse cyclone and the second spent catalyst flowing out from the catalyst outlet of the reaction cyclone separator to enter the stripping section.

[0016] Optionally, the mass flow rate ratio of the spent catalyst to the circulating catalyst is (0.5-10):1.

[0017] By the technical solution, the device for cracking reaction and the device for catalyst regeneration are independently arranged, so that the adaptability and safety of the system can be improved. The full-closed anti-coking cyclone assembly or the coarse-rotation top-rotation closed direct-connection assembly arranged in the reaction settler can reduce the risk of coking of high-temperature oil gas in the reaction settler, reduce the risk of secondary cracking, and thus improve the yield of the target product. In addition, the high-temperature reaction oil gas quencher arranged in the system of the present application can quickly reduce the temperature of the reaction oil gas at the outlet of the reactor, avoid the safety hazard caused by excessive thermal cracking and condensation coking of the reaction oil gas in the large oil gas pipeline at the outlet of the reactor, and effectively utilize the heat in the high-temperature reaction oil gas.

[0018] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, and are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation of the present disclosure. In the drawings:

[0020] Figure 1 is a schematic diagram of a system for catalytic conversion of light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons in Example 1 of the present disclosure.

[0021] Figure 2 is a schematic diagram of a system for catalytic conversion of light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons in Example 2 of the present disclosure.

[0022] Figure 3 is a schematic diagram of a system for catalytic conversion of light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons in Example 3 of the present disclosure.

[0023] Figure 4 is a schematic diagram of a system for catalytic conversion of light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons in Example 4 of the present disclosure.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1, riser reactor; 2, stripping section; 3, reaction settler; 4, oil gas quencher; 10, regenerated inclined pipe; 11, spent inclined pipe; 12, reaction circulating inclined pipe; 18, stripping section internal component; 19, stripping steam ring; 20, loosening steam ring; 21, cyclone quick separation head; 22, closed cover; 23, sealing cover plate; 24, slot; 25, reaction cyclone separator; 26, anti-coking steam ring; 27, reaction gas collection chamber; 28, oil gas distributor; 29, quencher baffle; 30, quenching medium distributor; 31, stirring steam ring; 100, pre-lifting medium; 101, back-fining medium; 102, light hydrocarbon oil feedstock; 103, dilution steam; 104, loosening steam; 105, stripping steam; 106, anti-coking steam; 107, stirring steam; 108, quenching medium; 109, temperature-reduced reaction oil gas; 110, heat-exchanged quencher; 121, coarse cyclone; 122, oil gas collection pipe; 124, oil gas closed guide pipe. DETAILED DESCRIPTION

[0026] The specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0027] The first aspect of the present disclosure provides a system for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of light hydrocarbon oil, which comprises a riser reactor 1, a reaction product purification and separation unit, and an oil gas quencher 4 arranged coaxially; the oil gas quencher 4 is arranged at the top of the reaction product purification and separation unit; the reaction product purification and separation unit comprises a stripping section 2 and a reaction settler 3 from bottom to top; the stripping section 2 and the reaction settler 3 are separated by a sealing cover plate 23;

[0028] The reaction settler 3 is provided with a fully-closed anti-coking cyclone assembly; the fully-closed anti-coking cyclone assembly comprises a cyclone quick separation head 21, a closed cover 22, and a reaction cyclone separator 25; the closed cover 22 is a sealed cylinder arranged at the upper part of the stripping section 2; the outlet at the upper part of the sealed cylinder is in communication with the inlet of the reaction cyclone separator 25 through a flow guide cylinder; the lower part of the sealed cylinder extends downward into the stripping section 2 through the sealing cover plate 23, and the lower part of the closed cover 22 is provided with a slot 24 to enable the inside and outside of the closed cover 22 to communicate only through the slot 24; the upper part of the riser reactor 1 is embedded inside the reaction product purification and separation unit, and the top of the riser reactor 1 extends into the sealed cylinder, and the cyclone quick separation head 21 is arranged at the top outlet of the riser reactor 1; or,

[0029] The coarse cyclone top cyclone sealing direct connection assembly comprises a coarse cyclone 121, an oil gas collecting pipe 122, an oil gas sealing guide pipe 124 and a reaction cyclone separator 25; the top outlet of the riser reactor 1 is communicated with the inside of the oil gas collecting pipe 122 through the coarse cyclone 121; the gas outlet of the oil gas collecting pipe 122 is communicated with the inlet of the reaction cyclone separator 25; the bottom inlet of the oil gas sealing guide pipe 124 extends downward to the gas phase space of the upper part of the stripping section 2 through the sealing cover plate 23; the gas phase space of the lower part of the sealing cover plate 23 is communicated with the oil gas collecting pipe 122 through the oil gas sealing guide pipe 124;

[0030] The stripping section 2 comprises a spent catalyst outlet and an optional reaction circulating catalyst outlet; the riser reactor 1 comprises a regenerated catalyst inlet and an optional reaction circulating catalyst inlet; the spent catalyst outlet of the stripping section 2 is communicated with the inlet of the catalyst regeneration device through the spent catalyst inclined pipe 11, so that the spent catalyst can enter the catalyst regeneration device for regeneration treatment; the regenerated catalyst inlet of the riser reactor 1 is communicated with the outlet of the catalyst regeneration device through the regenerated catalyst inclined pipe 10, so that the regenerated catalyst obtained by the catalyst regeneration device enters the riser reactor 1 to participate in the reaction; the reaction circulating catalyst outlet of the stripping section 2 is communicated with the reaction circulating catalyst inlet of the riser reactor 1 through the reaction circulating catalyst inclined pipe 12, so that the spent catalyst can return to the riser reactor 1 to participate in the reaction.

[0031] By the above technical solution, the device for carrying out the cracking reaction and the device for regenerating the catalyst are independently arranged, so that the adaptability and safety of the system can be improved. The full-closed anti-coking cyclone assembly or the coarse cyclone top cyclone sealing direct connection assembly is arranged in the reaction settler 3, so that the risk of coking of the high-temperature oil gas in the reaction settler 3 can be reduced, the risk of secondary cracking can be reduced, and the yield of the target product can be improved. In addition, the oil gas quencher 4 is arranged in the system of the present application, so that the temperature of the reaction oil gas at the outlet of the reactor can be quickly reduced, the safety hidden danger caused by excessive thermal cracking and condensation coking of the cooling reaction oil gas 109 in the large oil gas pipeline at the outlet of the reactor can be avoided, and the heat in the high-temperature reaction oil gas can be effectively utilized.

[0032] As Figure 1As shown, the riser reactor 1 includes a pre-lifting section, a variable diameter section, and a reaction section connected sequentially from bottom to top; the pre-lifting section and the reaction section are both cylindrical with equal diameters; the ratio of the inlet diameter of the reaction section to the diameter of the pre-lifting section is 1 to 5, preferably 1 to 3, and more preferably 1 to 2; the ratio of the lengths of the pre-lifting section, the variable diameter section, and the reaction section is 1:(0.05 to 0.5):(1 to 10), preferably 1:(0.1 to 0.3):(3 to 8), and more preferably 1:(0.1 to 0.2):(4 to 6).

[0033] The pre-lifting section is equipped with a pre-lifting medium nozzle, a regenerated catalyst inlet, and a recycle medium nozzle. The pre-lifting medium nozzle is connected to the pre-lifting medium source so that the pre-lifting medium 100 can enter the riser reactor 1 to lift the light hydrocarbon feedstock 102 and the regenerated catalyst to the reaction zone. The recycle medium nozzle is connected to the recycle medium source so that the recycle medium 101 can return to the riser reactor 1 to participate in the reaction. The regenerated catalyst inlet is connected to one end of the regeneration inclined tube 10 so that the regenerated catalyst can enter the riser reactor 1 through the regeneration inclined tube 10 to participate in the reaction.

[0034] In this embodiment, the mixed C4 and / or mixed C5 and / or cracked naphtha in the reaction products are returned to the riser reactor 1 for reprocessing; the mixed C4 and / or mixed C5 and / or cracked naphtha enter the riser reactor 1 before and / or after the light hydrocarbon feedstock nozzle; by reprocessing the mixed C4, mixed C5 and cracked naphtha, the yield of low-carbon olefins and low-carbon aromatics can be further improved.

[0035] The variable diameter section is equipped with a raw material nozzle, which is used to connect with a light hydrocarbon oil raw material source so that the light hydrocarbon oil raw material 102 can enter the variable diameter section of the riser reactor 1 and then enter the reaction zone through the pre-lifting medium 100.

[0036] The reaction section is equipped with a dilution steam nozzle, which is used to connect with a dilution steam source so that the dilution steam 103 can enter the riser reactor 1 to participate in the reaction.

[0037] like Figure 1 As shown, the shroud 22 in the fully enclosed anti-coking cyclone assembly used in this disclosure is a top-closed cylinder, wherein the cylinder of the shroud 22 includes a lower cylinder, a variable diameter section cylinder and a top cylinder connected sequentially from bottom to top.

[0038] The reaction cyclone separator 25 is at least one stage, preferably two stages; the outlet of the guide cylinder is in communication with the inlet of the first stage reaction cyclone separator, so that the oil gas material in the reaction product from the riser reactor 1 can enter the reaction cyclone separator 25 for separation, obtaining high-temperature reaction oil gas and spent catalyst material; the gas outlet of the last stage reaction cyclone separator is in communication with the inlet of the reaction gas collecting chamber 27, so that the reaction oil gas can enter the reaction gas collecting chamber 27 for use; the catalyst outlet of the reaction cyclone separator 25 extends downward through the sealing cover plate 23 to the gas phase space formed by the outer wall of the closed cover 22 and the sealing cover plate 23, so that the spent catalyst can enter the stripping section 2.

[0039] As shown in Figure 3 The crude cyclone 121 and the oil gas collecting pipe 122 in the crude cyclone top cyclone closed direct connection assembly used in the present disclosure are in closed communication with the outlet of the riser reactor 1.

[0040] The reaction cyclone separator 25 is at least one stage, preferably two stages; the gas outlet of the oil gas collecting pipe 122 is in communication with the inlet of the first stage reaction cyclone separator; the gas outlet of the last stage reaction cyclone separator is in communication with the inlet of the reaction gas collecting chamber 27, so that the oil gas material in the reaction product from the riser reactor 1 can enter the reaction cyclone separator 25 for separation, obtaining high-temperature reaction oil gas and spent catalyst material, and so that the reaction oil gas can enter the reaction gas collecting chamber 27 for use; the catalyst outlet of the crude cyclone 121, the outlet of the oil gas closed guide pipe 124, and the catalyst outlet of the reaction cyclone separator 25 extend downward through the sealing cover plate 23 to the gas phase space below the sealing cover plate 23, so that the spent catalyst can enter the stripping section 2.

[0041] In the above embodiments, the full-closed anti-coking cyclone assembly or the crude cyclone top cyclone closed direct connection assembly is arranged at the outlet of the riser reactor 1, so that the reaction product obtained by the reaction of the riser reactor 1 can directly enter the reaction cyclone separator 25 for separation under the action of the closed cover 22 or the oil gas collecting pipe 122, which can avoid the reaction product from staying in the reaction settler 3 with large volume for too long time to cause secondary cracking reaction, thereby improving the yield of low-carbon olefins and / or low-carbon aromatic hydrocarbons; on the other hand, it can avoid the reaction product from coking in the reaction settler 3, resulting in poor anti-fluctuation of the device. In order to further prevent the coking phenomenon in the reaction settler 3, the riser reactor 1 is preferably provided with a reaction cyclone separator 25. Figure 1As shown, the anti-coking steam ring 26 is arranged below the reaction plenum 27 and above the closure hood 22 or the oil-gas collection pipe 122; the inlet of the anti-coking steam ring 26 is used to communicate with the anti-coking steam source; the lower surface and / or the upper surface of the anti-coking steam ring 26 can be provided with steam injection holes to enable the anti-coking steam 106 to pass through the anti-coking steam ring 26 and spray steam through the steam injection holes.

[0042] The material and arrangement position of the sealing cover plate 23 used in the present disclosure are conventional choices in the art, which only need to set holes at different positions according to the components used in the reaction settler 3, for example, when the fully-closed anti-coking cyclone component is used in the reaction settler 3, the sealing cover plate 23 is tightly combined with or has a gap between the outer wall of the closure hood 22, the inner wall of the reaction settler 3 and the leg outer wall of the reaction cyclone separator 25; when the coarse-rotation top-rotation closed direct-connection component is used in the reaction settler 3, the sealing cover plate 23 is tightly combined with or has a gap between the outer wall of the riser reactor 1, the inner wall of the reaction settler 3, the leg outer wall of the coarse-rotation 121, the leg outer wall of the reaction cyclone separator 25 and the outer wall of the oil-gas closed guide pipe 124. In addition, the sealing cover plate 23 can be uniformly provided with a plurality of round holes to enable the fluid communication between the stripping section 2 and the reaction settler 3, wherein the diameter of the round holes is 1-100 mm.

[0043] The stripping section 2 includes stripping section internal components 18, at least one set of stripping steam rings 19 and loosening steam rings 20; the stripping section internal components 18 include one or more of herringbone baffle, annular baffle, disc umbrella baffle, packing and grid; the stripping steam rings 19 are located in the middle and / or lower part of the stripping section 2; the loosening steam rings 20 are located at the bottom of the stripping section 2; the upper surface and / or the lower surface of the stripping steam rings 19 and the loosening steam rings 20 are provided with steam wear-resistant nozzles.

[0044] The oil-gas quencher 4 comprises an oil-gas distributor 28, a quencher baffle 29, a quenching medium distributor 30 and a stirring steam ring 31. The oil-gas distributor 28 is located at the bottom of the oil-gas quencher 4, and the top outlet of the reaction settler 3 is communicated with the inlet of the oil-gas distributor 28, so that the high-temperature reaction oil-gas can enter the oil-gas distributor 28 for distribution. The quencher baffle 29 is located above the oil-gas distributor 28. The quencher baffle 29 has 1-20 layers, preferably 3-10 layers, and more preferably 4-8 layers. The quenching medium distributor 30 is located at the upper part of the quencher baffle 29. The lower surface of the quenching medium distributor 30 is provided with a plurality of injection holes, and the airflow direction of the injection holes of the quenching medium distributor 30 is vertically downward and / or obliquely downward. The stirring steam ring 31 is located at the lower part of the oil-gas quencher 4. The upper surface of the stirring steam ring 31 is provided with a plurality of injection holes, and the airflow direction of the injection holes of the stirring steam ring 31 is vertically upward and / or obliquely upward.

[0045] In this embodiment, the quenching medium 108 is heavy oil with an initial boiling point > 300℃, including but not limited to one or more combinations of self-produced cracking heavy oil, catalytic cracking slurry oil, catalytic cracking slurry oil, coking slurry oil, atmospheric residue, vacuum residue. The use of heavy oil can control the liquid temperature at the bottom of the oil-gas quencher 4 to be above 300℃, and this part of high-temperature liquid can be used to heat light and heavy hydrocarbon oil feedstock or generate steam, better utilize the high-temperature heat in the high-temperature reaction oil-gas, and reduce the energy consumption of the device. The oil-gas quencher 4 is directly arranged above the reaction settler 3 and integrated with the reaction settler 3; or the oil-gas quencher 4 is separately arranged near the reaction settler 3, so that the high-temperature reaction oil-gas can be cooled down in the shortest possible time to avoid coking of the high-temperature oil-gas. Due to the fact that the catalytic cracking gas yield of light hydrocarbon oil is much larger than that of conventional catalytic cracking, the total amount of catalyst fines entrained by the reaction oil-gas is larger, and the slurry oil yield is much lower than that of conventional catalytic cracking, which will lead to a high solid content in the slurry oil. In order to reduce the catalyst content in the quenching medium system 108, reduce the wear of equipment and pipelines, and ensure the long-term safe and stable operation of the device, the heat-exchanged quenching medium 110 is cooled by heat exchange and all or part of it enters the catalyst removal system to reduce the solid content and then circulates back to the oil-gas quencher 4. The catalyst removal system includes but is not limited to one or more combinations of filters, cyclones, centrifugal separators and electric filters.

[0046] The second aspect of the present disclosure adopts the system of the first aspect of the present disclosure to produce low-carbon olefins and aromatic hydrocarbons from catalytic conversion of light hydrocarbon oil, and the method comprises: feeding the light hydrocarbon oil feedstock 102 into the riser reactor 1 to contact with regenerated catalyst for cracking reaction to obtain reaction material containing cracking reaction products and spent catalyst; feeding the reaction material through the outlet of the riser reactor 1 into the full-closed anti-coking cyclone assembly or the coarse-cyclone top-cyclone closed direct connection assembly in the reaction settler 3 for separation treatment to obtain high-temperature reaction oil gas and spent catalyst material; feeding the high-temperature reaction oil gas into the oil gas quenching device 4 to exchange heat with the quenching medium 108 to obtain low-temperature reaction oil gas 109; further separating the low-temperature reaction oil to obtain low-carbon olefins and low-carbon aromatic hydrocarbons, and other products and back-refining medium 101; feeding the spent catalyst material into the stripping section 2 to contact with stripping steam 105 for stripping treatment to obtain spent catalyst; feeding the spent catalyst as spent agent through the spent catalyst inclined pipe 11 into the regeneration device; and optionally feeding part of the spent catalyst as reaction circulating catalyst through the reaction circulating inclined pipe 12 back to the riser reactor 1.

[0047] Through the above technical solution, the present application can maximize the catalytic conversion of light oil feedstocks such as gasoline, naphtha and kerosene into basic chemicals such as low-carbon olefins and low-carbon aromatic hydrocarbons, and can change the traditional fuel-type refinery or fuel-lubricating oil-type refinery into a chemical-type refinery, and can develop and extend the refinery from a single oil refinery to a chemical raw material production, which not only solves the problem of excess finished oil, but also increases the problem of shortage of chemical raw materials, and significantly improves the economic benefit of the enterprise.

[0048] The light hydrocarbon oil feedstock 102 used in the present disclosure is selected from light distillates with a distillation range of 20-300°C, and is preferably one or more of catalytic cracking gasoline, catalytic cracking gasoline, straight-run naphtha, coking naphtha, thermal cracking naphtha, thermal cracking naphtha, hydrogenated naphtha, reforming raffinate, straight-run kerosene and hydrogenated kerosene.

[0049] The catalyst used in the present disclosure is conventionally selected in the art, and the present application does not make special requirements, for example, the regenerated catalyst comprises zeolite, inorganic oxide and clay; the content of zeolite is 0.5-90% by weight, the content of inorganic oxide is 1-99% by weight, and the content of clay is 0-80% by weight, based on the total weight of the regenerated catalyst; the zeolite comprises mesoporous zeolite, mesoporous zeolite and optional macroporous zeolite; the content of mesoporous zeolite is 10-90% by weight, the content of mesoporous zeolite is 10-90% by weight, and the content of macroporous zeolite is 0-50% by weight, based on the total weight of the zeolite.

[0050] In one embodiment, the method further comprises introducing the recycle medium 101, the regenerated catalyst, the light hydrocarbon oil feedstock 102 and the dilution steam 103 into the riser reactor 1 and moving upward and reacting under the action of the pre-lift medium 100. The main operating conditions of the riser reactor 1 are as follows: the preheating temperature of the light hydrocarbon oil feedstock 102 is 40-600°C, preferably 100-400°C, and more preferably 200-300°C; the reaction temperature is 400-900°C, preferably 500-800°C, and more preferably 550-700°C; the reaction pressure is 0.01-1.0 MPa(g), preferably 0.05-0.4 MPa(g), and more preferably 0.1-0.2 MPa(g); the reaction time is 0.1-30 s, preferably 1-10 s, and more preferably 2-4 s; the mass flow rate ratio of the regenerated catalyst to the light hydrocarbon oil feedstock 102 is 1-100, preferably 10-50, and more preferably 20-40; and the mass flow rate ratio of the injected steam to the light hydrocarbon oil feedstock 102 is 0.05-2, preferably 0.1-0.5, and more preferably 0.2-0.4.

[0051] The pre-lift medium 100 is selected from one or more mixed gases of water vapor, nitrogen, catalytic dry gas, self-produced methane hydrogen gas and light hydrocarbon oil feedstock 102 gas.

[0052] In one embodiment, the operating conditions of the stripping section 2 include: the average gas apparent linear velocity of the gas is 0.05-1 m / s, preferably 0.1-0.5 m / s, and more preferably 0.2-0.4 m / s; and the average residence time of the catalyst is 0.5-10 min, preferably 1-5 min, and more preferably 2-4 min.

[0053] In one embodiment, the operating conditions of the reaction settler 3 include: the average gas apparent linear velocity is 0.01-1 m / s, preferably 0.03-0.5 m / s, and more preferably 0.05-0.2 m / s; and the pressure of the reaction settler 3 is 0-20 kPa higher than that of the stripping section 2, preferably 0.02-10 kPa, and more preferably 0.05-5 kPa.

[0054] In one embodiment, the operating conditions of the oil-gas quenching device 4 include: the temperature of the cooled reaction oil gas 109 at the outlet is 200-550°C, the temperature of the bottom liquid is 200-500°C, and the residence time of the bottom liquid is 0-15 min.

[0055] In one embodiment, the method further comprises, when a full-closed anti-coking cyclone assembly is used in the reaction settler 3, allowing the reaction material to pass through the cyclone quick separation head 21 at the outlet of the riser reactor 1 to obtain the first separated oil gas and the first spent catalyst by first separation; allowing the first spent catalyst to flow downward in the internal space of the closed cover 22 and flow into the stripping section 2; allowing the first separated oil gas to flow upward along the internal space of the closed cover 22 and enter the reaction cyclone 25 to obtain the high-temperature reaction oil gas and the second spent catalyst by second separation; allowing the high-temperature reaction oil gas to enter the reaction gas chamber 27 from the gas phase outlet of the reaction cyclone 25 and then enter the oil gas quenching device 4; and allowing the second spent catalyst to enter the gas phase space formed by the outer wall of the closed cover 22 and the sealing cover plate 23 from the catalyst outlet of the reaction cyclone 25 and finally enter the stripping section 2 through the slot 24.

[0056] In another embodiment, the method further comprises, when a coarse-rotation top-rotation cyclone closed direct-connection assembly is used in the reaction settler 3, allowing the reaction material to pass through the coarse-rotation cyclone 121 to obtain the first separated oil gas and the first spent catalyst by first separation; allowing the first separated oil gas to enter the reaction cyclone 25 to obtain the high-temperature reaction oil gas and the second spent catalyst by separation; allowing the high-temperature reaction oil gas to enter the reaction gas chamber 27 from the gas phase outlet of the reaction cyclone 25 and then enter the oil gas quenching device 4; and allowing the first spent catalyst flowing out of the catalyst outlet of the coarse-rotation cyclone 121 and the second spent catalyst flowing out of the catalyst outlet of the reaction cyclone 25 to enter the internal space of the stripping section 2.

[0057] In the above-mentioned embodiments, when the stripping section 2 is in a normal operating state, the loosening steam 104 and the stripping steam 105 can be allowed to enter the stripping section 2 to participate in stripping treatment; when the reaction settler 3 is in a normal operating state, the anti-coking steam 106 can be allowed to enter the reaction settler 3 to prevent coking; and when the oil gas quenching device 4 is in a normal operating state, the stirring steam 107 can be allowed to enter the oil gas quenching device 4 to perform stirring treatment. The loosening steam 104, the stripping steam 105, the anti-coking steam 106 and the stirring steam 107 are selected from 0.7-1.6 MPa(g) low-pressure steam and / or 1.6-4.6 MPa(g) medium-pressure steam, and are further superheated to 400-700°C, preferably superheated to 480-600°C.

[0058] In one embodiment, the method further comprises that the mass flow ratio of the spent agent to the reaction circulating catalyst is (0.5-10): 1, preferably (1-5): 1, and more preferably (2-4): 1.

[0059] The method provided by the present application is further described below by specific examples, but the present application is not limited by the examples. The catalyst used in the examples has the properties shown in Table 1, and the raw material used has the properties shown in Table 2.

[0060] Table 1 Catalyst properties

[0061] Item Unit Value Average particle size μm 50～100 Apparent density g / cm 3 ]] 0.75～0.90 Specific surface area m 2 / g]]> ≥100 Pore volume mL / g ≥0.2 Wear index wt% ≤4.0

[0062] Table 2 Properties of light hydrocarbon oil raw material

[0063] Item Unit Straight-run naphtha Straight-run kerosene Coking naphtha Processing amount Ten thousand tons / year 30.66 37.65 21.69 Proportion of raw material wt% 34.07 41.83 24.10 Distillation range ℃ 50～188 210～250 30～220 Density (20°C) kg / m 3 ]] 0.7296 0.8189 0.7320 Molecular weight - 140 220 160 Hydrogen content wt% 14.30 13.1 13.6

[0064] Example 1

[0065] The system for catalytically converting the light hydrocarbon oil used in this example to produce low-carbon olefins and aromatic hydrocarbons is shown in Figure 1

[0066] Taking a light hydrocarbon oil raw material 102 (a mixture of straight-run naphtha, straight-run kerosene and coking naphtha) with a feed amount of 0.9 million tons / year as an example, the method for catalytically converting light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons includes:

[0067] The light hydrocarbon oil raw material 102 is preheated to 300°C and then enters the riser reactor 1 to contact with the regenerated catalyst to perform a cracking reaction, to obtain a reaction material containing a cracking reaction product and spent catalyst.

[0068] The reaction material is subjected to a first separation by a cyclone quick separator 21 at the outlet of the riser reactor 1 to obtain a crude oil gas and a first spent catalyst; the first spent catalyst flows downward through the internal space of the closed cover 22 and flows into the stripping section 2; the crude oil gas flows upward along the internal space of the closed cover 22 and enters the reaction cyclone separator 25 through the flow guide cylinder to perform a second separation, to obtain the high-temperature reaction oil gas and the second spent catalyst; the high-temperature reaction oil gas enters the reaction gas chamber 27 from the gas phase outlet of the reaction cyclone separator 25, and the second spent catalyst enters the gas phase space formed by the outer wall of the closed cover 22 and the sealing cover plate 23 from the catalyst outlet of the reaction cyclone separator 25, and finally enters the internal space of the stripping section 2 through the slot 24.

[0069] ​The high-temperature reaction oil gas is made to enter the oil gas quenching device 4 from the reaction gas collecting chamber 27, and the high-temperature reaction oil gas is cooled to 350 DEG C by the heat-removed oil slurry to enter the product separation unit, and low-carbon olefins (ethylene, propylene), low-carbon aromatic hydrocarbons (benzene, toluene, xylene), methane hydrogen, ethane, propane, mixed carbon four, mixed carbon five, cracked naphtha, cracked light oil and cracked heavy oil and other products are separated. Part of the mixed carbon four, mixed carbon five and cracked naphtha are returned to the reaction riser reactor 1 to increase the yield of low-carbon olefins and low-carbon aromatic hydrocarbons. The spent catalyst separated by the full-closed anti-coking cyclone assembly is made to enter the stripping section 2 downward, and the spent catalyst is stripped of the entrained oil gas, and then the spent catalyst is made to enter the regeneration device through the spent catalyst inclined pipe 11, and the regenerated catalyst obtained after the coke-burning regeneration is made to return to the riser reactor 1 through the regenerated catalyst inclined pipe 10 for recycling.

[0070] The operating conditions of the method are shown in Table 3, and the product distribution of the device is shown in Table 4.

[0071] Example 2

[0072] The system for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of the light hydrocarbon oil used in this example is shown in Figure 2 ;

[0073] The method for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of the light hydrocarbon oil is the same as in Example 1, except that part of the spent catalyst is made to enter the regeneration device through the spent catalyst inclined pipe 11 as a spent agent, and the regenerated catalyst obtained after the coke-burning regeneration is made to return to the riser reactor 1 through the regenerated catalyst inclined pipe 10 for recycling; and the other part of the spent catalyst is made to return to the riser reactor 1 through the reaction recycling inclined pipe 12 as a reaction recycling catalyst for recycling.

[0074] The operating conditions of the method are shown in Table 3, and the product distribution of the device is shown in Table 4.

[0075] Example 3

[0076] The system for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of the light hydrocarbon oil used in this example is shown in Figure 3 ;

[0077] The method for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of the light hydrocarbon oil is the same as in Example 1, except that the reaction material is made to pass through the rough cyclone top and cyclone closed direct connection assembly for treatment, which specifically includes:

[0078] The reaction material is subjected to a first separation by a coarse cyclone 121 to obtain a coarse separation oil gas and a first spent catalyst; the coarse separation oil gas is subjected to a second separation by a reaction cyclone separator 25 to obtain the high-temperature reaction oil gas and the second spent catalyst; the high-temperature reaction oil gas is subjected to a gas phase outlet from the reaction cyclone separator 25 into a reaction gas collecting chamber 27; the first spent catalyst from a catalyst outlet of the coarse cyclone 121 and the second spent catalyst from a catalyst outlet of the reaction cyclone separator 25 are subjected to an inside of the stripping section 2.

[0079] The operating conditions of the method are shown in Table 3; the product distribution of the device is shown in Table 4.

[0080] Example 4

[0081] The system for catalytically converting a light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons used in this example is shown in Figure 4

[0082] The method for catalytically converting a light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons is the same as in Example 3, except that a part of the spent catalyst is subjected to a coke-burning regeneration in a regeneration device as a spent agent through a spent catalyst inclined pipe 11, and the regenerated catalyst obtained is returned to the riser reactor 1 through a regenerated catalyst inclined pipe 10 for recycling; another part of the spent catalyst is returned to the riser reactor 1 through a reaction recycling inclined pipe 12 for recycling as a reaction recycling catalyst.

[0083] The operating conditions of the method are shown in Table 3; the product distribution of the device is shown in Table 4.

[0084] Comparative Example 1

[0085] The method for catalytically converting a light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons according to the patent CN103509589A specifically includes: using straight-run naphtha as a raw material, performing a test on a medium-sized device of a riser reactor, preheating the raw material oil to enter the bottom of the riser reactor, performing a cracking reaction under the conditions of a reaction temperature of 675°C, a reaction time of 2 seconds, a weight ratio of the catalytic cracking catalyst to the raw material oil of 25, and a weight ratio of water vapor to the raw material oil of 0.55, the reaction products, water vapor, and spent catalyst are subjected to a closed cyclone separator from an outlet of the reactor, the reaction products and the catalyst are rapidly separated, the reaction products are cut according to the distillation range after heat exchange with the raw material in a separation system, thereby obtaining dry gas, propylene, carbon four, and gasoline fractions. The spent catalyst is subjected to a regenerator under the action of gravity, and is regenerated by contacting with air. The regenerated catalyst is subjected to a degassing tank to remove non-hydrocarbon gas impurities adsorbed and carried by the regenerated catalyst. The stripped regenerated catalyst is returned to the riser reactor for recycling.

[0086] The operating conditions of the method are shown in Table 3; the product distribution of the device is shown in Table 4. ​

[0087] Table 3 Operating conditions

[0088]

[0089]

[0090] Table 4 Product distribution of the device

[0091]

[0092]

[0093] As shown in Table 4, according to the comparison of the data of Examples 1-4 and Comparative Example 1, it can be known that, by using the technical scheme of the present disclosure, low-carbon olefins and aromatic hydrocarbons can be produced by catalytic conversion of light hydrocarbon oil, and by arranging the full-closed anti-coking cyclone assembly or the coarse-rotation top-rotation closed direct-connection assembly in the reaction settler, the risk of coking of high-temperature oil gas in the reaction settler can be reduced, the risk of secondary cracking can be reduced, and the yield of the target product can be improved.

[0094] The preferred embodiments of the present disclosure are described in detail above with reference to the drawings, but the present disclosure is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical scheme of the present disclosure within the technical concept of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

[0095] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, various possible combination manners are not described again in the present disclosure.

[0096] In addition, any combination of various different embodiments of the present disclosure can also be made as long as it does not deviate from the idea of the present disclosure, and it should also be considered as the disclosed content of the present disclosure.

Claims

1. A system for the catalytic conversion of light hydrocarbon oils to produce lower carbon olefins and aromatic hydrocarbons, characterized by, The system comprises a riser reactor (1), a reaction product purification separation unit and an oil gas quenching device (4) arranged coaxially; the oil gas quenching device (4) is arranged at the top of the reaction product purification separation unit; the reaction product purification separation unit comprises a stripping section (2) and a reaction settler (3) from bottom to top; the stripping section (2) and the reaction settler (3) are separated by a sealing cover plate (23); The reaction settler (3) is provided with a fully-closed anti-coking cyclone assembly; the fully-closed anti-coking cyclone assembly comprises a cyclone quick separation head (21), a closed cover (22) and a reaction cyclone separator (25); the closed cover (22) is a sealing cylinder arranged at the upper part of the stripping section (2); the outlet at the upper part of the sealing cylinder is communicated with the inlet of the reaction cyclone separator (25) through a flow guide cylinder; the lower part of the sealing cylinder extends downward into the stripping section (2) through the sealing cover plate (23), and the lower part of the closed cover (22) is provided with a notch (24) so that the inner side and the outer side of the closed cover (22) are communicated only through the notch (24); the upper part of the riser reactor (1) is embedded in the reaction product purification separation unit, and the top of the riser reactor (1) extends into the sealing cylinder, and the cyclone quick separation head (21) is arranged at the top outlet of the riser reactor (1); or, The reaction settler (3) is provided with a coarse cyclone top cyclone sealing direct connection assembly; the coarse cyclone top cyclone sealing direct connection assembly comprises a coarse cyclone (121), an oil gas collecting pipe (122), an oil gas sealing guide pipe (124) and a reaction cyclone separator (25); the top outlet of the riser reactor (1) is communicated with the inside of the oil gas collecting pipe (122) through the coarse cyclone (121); the gas outlet of the oil gas collecting pipe (122) is communicated with the inlet of the reaction cyclone separator (25); the bottom inlet of the oil gas sealing guide pipe (124) extends downward into the gas phase space at the upper part of the stripping section (2) through the sealing cover plate (23); the gas phase space at the lower part of the sealing cover plate (23) is communicated with the oil gas collecting pipe (122) through the oil gas sealing guide pipe (124); The stripping section (2) comprises a spent catalyst outlet; the riser reactor (1) comprises a regenerated catalyst inlet; the spent catalyst outlet of the stripping section (2) is communicated with the inlet of the catalyst regeneration device through a spent catalyst inclined pipe (11); the regenerated catalyst inlet of the riser reactor (1) is communicated with the outlet of the catalyst regeneration device through a regenerated catalyst inclined pipe (10).

2. The system of claim 1, wherein, The stripping section (2) further comprises a reaction circulating catalyst outlet; the riser reactor (1) further comprises a reaction circulating catalyst inlet; The reaction circulating catalyst outlet of the stripping section (2) is communicated with the reaction circulating catalyst inlet of the riser reactor (1) through a reaction circulating inclined pipe (12).

3. The system of claim 1, wherein, The riser reactor (1) comprises a pre-lifting section, a variable-diameter section and a reaction section which are sequentially communicated from bottom to top; the pre-lifting section and the reaction section are both equal-diameter cylindrical; The ratio of the inlet diameter of the reaction section to the diameter of the pre-lifting section is 1-5; the length ratio of the pre-lifting section, the variable-diameter section and the reaction section is 1:(0.05-0.5):(1-10); The pre-lifting section is provided with a pre-lifting medium nozzle, a regenerated catalyst inlet and a back-fining medium nozzle; the pre-lifting medium nozzle is used for being communicated with a pre-lifting medium source, the back-fining medium nozzle is used for being communicated with a back-fining medium source, and the regenerated catalyst inlet is communicated with one end of the regenerated inclined pipe (10); The variable-diameter section is provided with a raw material nozzle which is used for being communicated with a light hydrocarbon oil raw material source; The reaction section is provided with a dilution steam nozzle which is used for being communicated with a dilution steam source.

4. The system of claim 1, wherein, The reaction settler (3) is further provided with a reaction gas collecting chamber (27) and an anti-coking steam ring (26) located below the reaction gas collecting chamber (27); The outlet of the reaction gas collecting chamber (27) is communicated with the top outlet of the reaction settler (3); The inlet of the anti-coking steam ring (26) is used for being communicated with an anti-coking steam source; steam injection holes are formed in the upper surface and / or the lower surface of the anti-coking steam ring (26); The reaction cyclone separator (25) is at least one stage; The outlet of the draft tube is communicated with the inlet of the first-stage reaction cyclone separator; the gas outlet of the last-stage reaction cyclone separator is communicated with the inlet of the reaction gas collecting chamber (27); the catalyst outlet of the reaction cyclone separator (25) extends downward to the gas phase space formed by the outer wall of the closed cover (22) and the sealing cover plate (23) through a leg passing through the sealing cover plate (23); or, The gas outlet of the oil gas collecting pipe (122) is communicated with the inlet of the first-stage reaction cyclone separator; the gas outlet of the last-stage reaction cyclone separator is communicated with the inlet of the reaction gas collecting chamber (27); the catalyst outlet of the coarse cyclone (121), the inlet of the oil gas closed guide pipe (124) and the catalyst outlet of the reaction cyclone separator (25) extend downward to the gas phase space below the sealing cover plate (23) through legs passing through the sealing cover plate (23).

5. The system of claim 4, wherein, The reaction cyclone separator (25) is two stages.

6. The system of claim 1, wherein, The stripping section (2) comprises a stripping section internal component (18), at least one group of stripping steam rings (19) and loosening steam rings (20); The stripping section internal component (18) comprises one or more of a herringbone baffle, an annular baffle, a disc umbrella baffle, a packing and a grid; The stripping steam rings (19) are located in the middle and / or lower part of the stripping section (2); The loosening steam rings (20) are located in the bottom of the stripping section (2); The upper surface and / or the lower surface of the stripping steam rings (19) and the loosening steam rings (20) are provided with steam wear-resistant nozzles.

7. The system of claim 1, wherein, The oil gas quencher (4) comprises an oil gas distributor (28), a quencher baffle (29), a quenching medium distributor (30) and a stirring steam ring (31). The oil gas distributor (28) is located at the bottom of the oil gas quencher (4) and the top outlet of the reaction settler (3) is communicated with the inlet of the oil gas distributor (28); The quencher baffle (29) is located above the oil gas distributor (28); the number of layers of the quencher baffle (29) is 1-20 layers; The quenching medium distributor (30) is located at the upper part of the quencher baffle (29); the lower surface of the quenching medium distributor (30) is provided with a plurality of spray holes, and the airflow direction of the spray holes of the quenching medium distributor (30) is vertically downward and / or obliquely downward; The stirring steam ring (31) is located at the lower part of the oil gas quencher (4); the upper surface of the stirring steam ring (31) is provided with a plurality of spray holes, and the airflow direction of the spray holes of the stirring steam ring (31) is vertically upward and / or obliquely upward.

8. A process for the catalytic conversion of light hydrocarbon oils to lower olefins and aromatic hydrocarbons using the system according to any one of claims 1 to 7, characterized in that, The method comprises: The light hydrocarbon oil raw material is introduced into the riser reactor (1) to contact with the regenerated catalyst to perform a cracking reaction, so as to obtain a reaction material containing a cracking reaction product and spent catalyst; The reaction material is introduced into the full-closed anti-coking cyclone assembly or the coarse-rotation top-rotation closed direct-connection assembly in the reaction settler (3) through the outlet of the riser reactor (1) to perform separation treatment, so as to obtain high-temperature reaction oil gas and spent catalyst material; The high-temperature reaction oil gas is introduced into the oil gas quencher (4) to exchange heat with a quenching medium, so as to obtain cooled reaction oil gas; the cooled reaction oil gas is further separated, so as to obtain low-carbon olefins and low-carbon aromatic hydrocarbons; The spent catalyst material is introduced into the stripping section (2) to contact with stripping steam to perform stripping treatment, so as to obtain spent catalyst; the spent catalyst is introduced into a regeneration device through a spent catalyst inclined pipe (11) as spent agent.

9. The method of claim 8, wherein, Part of the spent catalyst is introduced into the riser reactor (1) through a reaction cycle inclined pipe (12) as reaction cycle catalyst.

10. The method of claim 8, wherein, The light hydrocarbon oil raw material is selected from light distillate with a distillation range of 20-300℃; The regenerated catalyst comprises zeolite, inorganic oxide and clay; the content of the zeolite is 0.5-90% by weight, the content of the inorganic oxide is 1-99% by weight, and the content of the clay is 0-80% by weight, based on the total weight of the regenerated catalyst; the zeolite comprises mesoporous zeolite and mesoporous zeolite; the content of the mesoporous zeolite is 10-90% by weight, and the content of the mesoporous zeolite is 10-90% by weight, based on the total weight of the zeolite; The quenching medium is selected from heavy oil products with an initial distillation point of above 300℃.

11. The method of claim 10, wherein, The light hydrocarbon oil raw material is selected from one or more of catalytic cracking gasoline, catalytic cracking gasoline, straight-run naphtha, coking naphtha, thermal cracking naphtha, thermal cracking naphtha, hydrogenated naphtha, reforming raffinate, straight-run kerosene and hydrogenated kerosene; The zeolite further comprises macroporous zeolite; the content of the macroporous zeolite is 0-50% by weight, based on the total weight of the zeolite; The quenching medium is selected from one or more of cracking heavy oil, catalytic cracking slurry oil, catalytic cracking slurry oil, coking slurry oil, atmospheric residue and vacuum residue.

12. The method of claim 8, wherein, The reaction conditions of the cracking reaction include: preheating temperature of 40-600℃, reaction temperature of 400-900℃, reaction pressure of 0.01-1.0 MPaG, reaction time of 0.1-30 s, mass flow rate ratio of the regenerated catalyst to the light hydrocarbon oil feedstock of 1-100, and mass flow rate ratio of water vapor to the light hydrocarbon oil feedstock of 0.05-2; The operating conditions of the stripping section (2) include: average gas superficial linear velocity of 0.05-1 m / s, and average residence time of the catalyst of 0.5-10 min. The operating conditions of the oil gas quencher (4) include: temperature of the temperature-reduced reaction oil gas at the outlet of 200-550℃, temperature of the bottom liquid of 200-500℃, and residence time of the bottom liquid of 0-15 min.

13. The method of claim 8, wherein, The method further includes: subjecting the reaction material to first separation by a cyclone quick separation head (21) at the outlet of the riser reactor (1) to obtain crude separation oil gas and first spent catalyst; subjecting the first spent catalyst to downward flow in the internal space of a closed cover (22) and flow into the stripping section (2); subjecting the crude separation oil gas to upward flow along the internal space of the closed cover (22) and enter a reaction cyclone separator (25) through a flow guide cylinder to undergo second separation to obtain the high-temperature reaction oil gas and second spent catalyst; and subjecting the high-temperature reaction oil gas to enter the oil gas quencher (4) from the gas phase outlet of the reaction cyclone separator (25), and subjecting the second spent catalyst to flow into the gas phase space formed by the outer wall of the closed cover (22) and the sealing cover plate (23) from the catalyst outlet of the reaction cyclone separator (25), and finally enter the stripping section (2) through the slot (24); or, The method further includes: subjecting the reaction material to second separation by a coarse cyclone (121) to obtain crude separation oil gas and first spent catalyst; subjecting the crude separation oil gas to enter the reaction cyclone separator (25) to undergo second separation to obtain the high-temperature reaction oil gas and second spent catalyst; subjecting the high-temperature reaction oil gas to enter the oil gas quencher (4) from the gas phase outlet of the reaction cyclone separator (25); and subjecting the first spent catalyst flowing out from the catalyst outlet of the coarse cyclone (121) and the second spent catalyst flowing out from the catalyst outlet of the reaction cyclone separator (25) to enter the stripping section (2).

14. The method of claim 8, wherein, The mass flow rate ratio of the spent catalyst to the circulating catalyst is (0.5-10):1.

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