Downflow bed reaction system and method for producing lower carbon olefins and aromatic hydrocarbons

Abstract

The present disclosure relates to a down-flow bed reaction system and method for producing low-carbon olefins and aromatics from 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 down-flow bed reactor in the order of gravitational field can reduce the gas-solid axial back mixing, and thus can improve the yield of low-carbon olefins and low-carbon aromatics. The second regeneration catalyst cooler is arranged on the second regeneration inclined pipe, which can flexibly adjust the catalyst activity and concentration in the down-flow bed reactor, significantly increase the catalyst-oil ratio, improve the yield of low-carbon olefins and low-carbon aromatics, and reduce the yield of methane hydrogen and coke. In addition, the high-temperature reaction oil gas quencher arranged in the system of the present disclosure can quickly reduce the temperature of the reaction oil gas, avoid the safety hazards caused by excessive thermal cracking and condensation coking of the reaction oil gas in the reactor outlet large oil gas pipeline, 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 downflow bed reaction system and method for producing 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 an important role in the petrochemical industry.

[0003] In recent years, new technologies for producing low-carbon olefins and low-carbon aromatic hydrocarbons have attracted more and more attention, 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, Chinese patents CN103509589A, CN103509593A, CN103509594A and CN103509595A disclose a catalytic conversion method of light hydrocarbon oil. The light hydrocarbon oil raw material enters the catalytic cracking device for catalytic cracking reaction, and the generated reaction oil gas is separated to obtain low-carbon olefins. The spent catalyst is regenerated and recycled. The C4 light fraction in the reaction product is returned to the riser reactor for refining. In order to reduce the heat dissipation energy consumption of the reactor, the riser reactor and other all or part of the reactor components are arranged inside the regenerator. In order to further meet the heat demand of the reaction-regeneration system, fuel is directly introduced into the regenerator and / or the spent inclined pipe.

[0004] The above-mentioned prior art proposes a method for converting petroleum hydrocarbon raw materials into low-carbon olefins through a catalytic cracking (cracking) reaction process, but 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, and other problems in the catalytic conversion process of light hydrocarbon oil, and does not involve the recovery of high-value low-carbon aromatic hydrocarbons and the scheme for improving the yield of low-carbon aromatic hydrocarbons. SUMMARY

[0005] The purpose of the present disclosure is to provide a downflow bed reaction system and method for producing 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, and other problems in the prior art.

[0006] To achieve the above object, the first aspect of the present disclosure provides a down-flow bed reaction system for producing low-carbon olefins and aromatic hydrocarbons, which comprises a down-flow bed reactor, a reaction product purification separation unit, an oil gas quenching device and a regenerator; the reaction product purification separation unit and the oil gas quenching device are coaxially arranged, and the oil gas quenching device is arranged at the top of the reaction product purification separation unit; the reaction product purification 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; the down-flow bed reactor and the reaction product purification separation unit are arranged side by side; the stripping section comprises a spent catalyst outlet; the down-flow bed reactor comprises a first regenerated catalyst inlet and a second catalyst inlet; the regenerator comprises a spent catalyst inlet, a first regenerated catalyst outlet and a second regenerated catalyst outlet; the spent catalyst inlet of the regenerator is connected to the spent catalyst outlet of the stripping section through a spent catalyst inclined pipe; the first regenerated catalyst outlet of the regenerator is connected to the first regenerated catalyst inlet of the down-flow bed reactor through a first regenerated catalyst inclined pipe; the second regenerated catalyst outlet of the regenerator is connected to the second regenerated catalyst inlet of the down-flow bed reactor through a second regenerated catalyst inclined pipe; and the second regenerated catalyst inclined pipe is provided with a second regenerated catalyst cooler.

[0007] Optionally, the reaction settler is provided with a fully-closed anti-coking cyclone assembly; 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 connected to 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 enable the inside and outside of the closed cover to communicate only through the notch; the end of the down-flow bed reactor is embedded inside the reaction product purification separation unit, and the end of the down-flow bed reactor extends into the sealing cylinder, and the cyclone quick separation head is arranged at the end outlet of the down-flow bed reactor; or, the reaction settler is provided with a coarse-rotation top-rotation closed direct connection assembly; the coarse-rotation top-rotation closed direct connection assembly comprises a coarse rotation, an oil gas collecting pipe, an oil gas closed guide pipe and a reaction cyclone separator; the end outlet of the down-flow bed reactor is connected to the inside of the oil gas collecting pipe through the coarse rotation; the gas outlet of the oil gas collecting pipe is connected to the inlet of the reaction cyclone separator; and the bottom inlet of the oil gas closed 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 and the oil gas collecting pipe are connected through the oil gas closed guide pipe.

[0008] Optionally, the reaction settler is further provided with a reaction gas collection chamber; the outlet of the reaction gas collection chamber is communicated with the top outlet of the reaction settler; the reaction cyclone separator is at least two stages; 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 collection chamber; the catalyst outlet of the reaction cyclone separator extends downward through the seal cover plate to the gas phase space formed by the outer wall of the closed cover and the seal cover plate; or, the gas outlet of the oil gas collection pipe 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 collection chamber; the catalyst outlet of the coarse cyclone, the inlet of the oil gas closed guide pipe and the catalyst outlet of the reaction cyclone separator extend downward through the seal cover plate to the gas phase space.

[0009] Optionally, the downflow bed reaction system further comprises an equal-diameter cylindrical riser; the lower part of the riser is provided with the first regenerated catalyst inlet communicated with the outlet of the first regenerated inclined pipe and the second regenerated catalyst inlet communicated with the outlet of the second regenerated inclined pipe and arranged above the first regenerated catalyst inlet; or, the lower part of the riser is provided with a spent catalyst inlet and the upper part is provided with a spent catalyst outlet; the spent catalyst inlet of the riser is communicated with the outlet of the spent inclined pipe and the spent catalyst outlet of the riser is communicated with the spent catalyst inlet of the regenerator.

[0010] Optionally, the stripping section comprises a stripping section internal component, at least one set of stripping steam rings and loosening steam rings; the stripping section internal component comprises one or more of a herringbone baffle, an annular baffle, a disc umbrella baffle, a packing and a grid; 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, the airflow direction of the injection holes of the quenching medium distributor is vertical downward and / or oblique 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, the airflow direction of the injection holes of the stirring steam ring is vertical upward and / or oblique upward.

[0012] The second aspect of the present disclosure adopts the down-flow bed reaction system of the first aspect of the present disclosure to produce low-carbon olefins and aromatic hydrocarbons from catalytic conversion of light hydrocarbon oil, which comprises: introducing the light hydrocarbon oil feedstock into the down-flow bed reactor to contact with the first regenerated catalyst and the second regenerated catalyst to perform a cracking reaction, to obtain a reaction material containing cracking reaction products and spent catalyst; introducing the reaction material through the outlet of the down-flow bed reactor into a reaction settler to perform separation treatment, to obtain high-temperature reaction oil gas and spent catalyst material; introducing the spent catalyst material into a stripping section to perform stripping treatment, to obtain spent catalyst; introducing the spent catalyst through a spent catalyst inclined pipe into a regenerator to perform regeneration treatment, to obtain regenerated catalyst; introducing a portion of the regenerated catalyst as the first regenerated catalyst through a first regenerated catalyst inclined pipe into the down-flow bed reactor; introducing another portion of the regenerated catalyst as the second regenerated catalyst through a second regenerated catalyst inclined pipe into a second regenerated catalyst cooler for cooling, and then into the down-flow bed reactor; introducing the high-temperature reaction oil gas into an oil gas quencher to exchange heat with a quenching medium, to obtain cooled reaction oil gas 110; and further separating the low-temperature reaction oil to obtain low-carbon olefins and low-carbon aromatic hydrocarbons.

[0013] Optionally, the light hydrocarbon oil feedstock is selected from light distillates with a distillation range of 20-300°C, 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; 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 optionally 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; and the quenching medium is selected from heavy oil products with an initial boiling point above 300°C, preferably one or more of pyrolysis 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; 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; and a mass flow rate ratio of the regenerated catalyst passing through the first regeneration inclined pipe to the second regeneration inclined pipe is (1-50):1.

[0015] Optionally, the reaction settler is provided with a fully-closed anti-coking cyclone assembly; the fully-closed anti-coking cyclone assembly includes a cyclone quick separation head, a closed cover, and a reaction cyclone separator; or, the reaction settler is provided with a coarse cyclone top cyclone closed direct connection assembly; the coarse cyclone top cyclone closed direct connection assembly includes a coarse cyclone, an oil gas collecting pipe, an oil gas closed guide pipe, and a reaction cyclone separator; the method further includes: making the reaction material pass through the cyclone quick separation head at the outlet of the downflow bed reactor to obtain a coarse separation oil gas and a first spent catalyst through first separation; making the first spent catalyst flow downward in the internal space of the closed cover and flow into the stripping section; making the coarse separation oil gas flow upward in the internal space of the closed cover and enter the reaction cyclone separator through the draft tube to obtain the high-temperature reaction oil gas and the second spent catalyst through second separation; making the high-temperature reaction oil gas enter the oil gas quencher from the gas phase outlet of the reaction cyclone separator; and making the second spent catalyst flow into the 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: making the reaction material pass through the coarse cyclone and the oil gas collecting pipe to obtain a coarse separation oil gas and a first spent catalyst through first separation; making the coarse separation oil gas enter the reaction cyclone separator to obtain the high-temperature reaction oil gas and the second spent catalyst through separation; making the high-temperature reaction oil gas enter the oil gas quencher from the gas phase outlet of the reaction cyclone separator; and making the first spent catalyst flowing out of the catalyst outlet of the coarse cyclone and the second spent catalyst flowing out of the catalyst outlet of the reaction cyclone separator enter the stripping section.

[0016] 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 down-flow bed reactor in the gravity field can reduce the gas-solid axial back mixing, and thus the yield of low-carbon olefins and low-carbon aromatic hydrocarbons can be improved. The regenerated catalyst cooler is arranged on the second regeneration inclined pipe, and is used for reducing the temperature of part of the regenerated catalyst. The catalyst activity and concentration in the down-flow bed reactor can be flexibly adjusted, the catalyst-oil ratio is significantly increased, the contact area between the raw material and the catalyst is improved, the catalytic reaction is significantly enhanced, the yield of low-carbon olefins and low-carbon aromatic hydrocarbons is improved, and the yield of methane and coke is reduced. In addition, the high-temperature reaction oil gas quencher is arranged in the system, so that the temperature of the reaction oil gas can be quickly reduced, the safety hidden danger caused by excessive thermal cracking and condensation coking of the reaction oil gas in the pipeline can be avoided, and the heat in the high-temperature reaction oil gas can be effectively utilized.

[0017] Other features and advantages of the present disclosure will be described in detail in the following detailed description section. BRIEF DESCRIPTION OF DRAWINGS

[0018] 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 on the present disclosure. In the drawings:

[0019] Figure 1 is a schematic diagram of a down-flow bed reaction system for producing low-carbon olefins and aromatic hydrocarbons in Example 1 of the present disclosure.

[0020] Figure 2 is a schematic diagram of a down-flow bed reaction system for producing low-carbon olefins and aromatic hydrocarbons in Example 2 of the present disclosure.

[0021] Figure 3 is a schematic diagram of a down-flow bed reaction system for producing low-carbon olefins and aromatic hydrocarbons in Example 3 of the present disclosure.

[0022] Figure 4 is a schematic diagram of a down-flow bed reaction system for producing low-carbon olefins and aromatic hydrocarbons in Example 4 of the present disclosure.

[0023] BRIEF DESCRIPTION OF DRAWINGS

[0024] 1 riser; 2 downer reactor; 3 stripping section; 4 reaction settler; 5 oil gas quencher; 6 regenerator; 7 second regenerated catalyst cooler; 8 second regenerated catalyst dipleg; 10 second regenerated catalyst slide valve; 11 first regenerated catalyst dipleg; 12 first regenerated catalyst slide valve; 13 spent catalyst dipleg; 14 spent catalyst slide valve; 15 main air distributor; 16 regenerated cyclone; 17 regenerated plenum; 18 stripping steam ring; 19 steam ring for loosening; 21 cyclonic quick separation head; 22 closure cap; 23 sealing cover plate; 24 slot; 25 reaction cyclone; 26 anti-coking steam ring; 27 reaction plenum; 28 oil gas distributor; 29 quencher baffle; 30 quenching medium distributor; 31 agitation steam ring; 100 pre-lift medium; 101 back-fining medium; 102 light hydrocarbon oil feedstock; 103 dilution steam; 104 loosening steam; 105 stripping steam; 106 anti-coking steam; 107 heat exchange quenching medium; 108 agitation steam; 109 quenching medium; 110 cooled reaction oil gas; 111 coking main air; 112 regenerated flue gas; 121 coarse spinning; 122 oil gas collecting pipe; 124 oil gas closed guide pipe. DETAILED DESCRIPTION

[0025] 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 merely intended for illustration and explanation of the present disclosure and are not intended to limit the present disclosure.

[0026] The first aspect of the present disclosure provides a down-flow bed reaction system for producing low-carbon olefins and aromatic hydrocarbons, which comprises a down-flow bed reactor 2, a reaction product purification separation unit, an oil gas quencher 5 and a regenerator 6; the reaction product purification separation unit and the oil gas quencher 5 are coaxially arranged and the oil gas quencher 5 is arranged at the top of the reaction product purification separation unit; the reaction product purification separation unit comprises a stripping section 3 and a reaction settler 4 in sequence from bottom to top, and the stripping section 3 and the reaction settler 4 are separated by a sealing cover plate 23; the down-flow bed reactor 2 and the reaction product purification separation unit are arranged side by side; the stripping section 3 comprises a spent catalyst outlet; the down-flow bed reactor 2 comprises a first regenerated catalyst inlet and a second catalyst inlet; the regenerator 6 comprises a spent catalyst inlet, a first regenerated catalyst outlet and a second regenerated catalyst outlet; the spent catalyst inlet of the regenerator 6 is in communication with the spent catalyst outlet of the stripping section 3 through a spent catalyst inclined pipe 13; the first regenerated catalyst outlet of the regenerator 6 is in communication with the first regenerated catalyst inlet of the down-flow bed reactor 2 through a first regenerated catalyst inclined pipe 11; the second regenerated catalyst outlet of the regenerator 6 is in communication with the second regenerated catalyst inlet of the down-flow bed reactor 2 through a second regenerated catalyst inclined pipe 8; wherein the second regenerated catalyst inclined pipe 8 is provided with a second regenerated catalyst cooler 7.

[0027] By the above technical solution, the device for performing cracking reaction and the device for regenerating catalyst are independently arranged, which can improve the adaptability and safety of the system. The down-flow bed reactor 2 in the gravitational field can reduce the gas-solid axial backmixing, thereby improving the yield of low-carbon olefins and low-carbon aromatic hydrocarbons. The second regenerated catalyst cooler 7 is arranged on the second regenerated catalyst inclined pipe 8, which is used to reduce the temperature of part of the regenerated catalyst, so as to flexibly adjust the catalyst activity and concentration in the down-flow bed reactor 2, significantly increase the catalyst-oil ratio, improve the contact area between the raw material and the catalyst, significantly enhance the catalytic reaction, improve the yield of low-carbon olefins and low-carbon aromatic hydrocarbons, and reduce the yield of methane hydrogen and coke. In addition, the oil gas quencher 5 is arranged in the system of the present application, which can quickly reduce the temperature of the reaction oil gas at the outlet of the reactor, avoid the safety hidden danger 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.

[0028] As Figure 1As shown, the down-flow bed reaction system further comprises an equal-diameter cylindrical riser 1; wherein the riser 1 can be combined with the down-flow bed reactor 2, specifically, the lower part of the riser 1 is provided with the first regenerated catalyst inlet for communicating with the outlet of the first regenerated inclined pipe 11, so that the first regenerated catalyst can enter the riser 1 through the first regenerated inclined pipe 11; and the second regenerated catalyst inlet provided above the first regenerated catalyst inlet for communicating with the outlet of the second regenerated inclined pipe 8, so that the second regenerated catalyst can enter the riser 1 through the second regenerated inclined pipe 8.

[0029] Wherein, the bottom of the riser 1 is provided with a lifting medium nozzle, and the lifting medium nozzle is used for communicating with a pre-lifting medium source, so that the regenerated catalyst entering the lower part of the riser 1 can enter the down-flow bed reactor 2 with the lifting medium to participate in the reaction.

[0030] Wherein, the middle part of the riser 1 is provided with a back-fining medium nozzle, and the back-fining medium nozzle is used for communicating with a back-fining medium source, so that the back-fining medium 101 entering the middle part of the riser 1 can enter the down-flow bed reactor 2 with the lifting medium for recycling.

[0031] Wherein, the top of the down-flow bed reactor 2 is provided with a light hydrocarbon oil feedstock nozzle, and the light hydrocarbon oil feedstock nozzle is used for communicating with a light hydrocarbon oil feedstock source, so as to introduce the light hydrocarbon oil feedstock 102.

[0032] Wherein, the middle part of the down-flow bed reactor 2 is provided with a dilution steam nozzle, and the dilution steam nozzle is used for communicating with a dilution steam source, so that the dilution steam 103 can dilute the reaction material and improve the reaction performance.

[0033] As shown, Figure 3 the lower part of the riser 1 is provided with a spent catalyst inlet and the upper part is provided with a spent catalyst outlet; the spent catalyst inlet of the riser 1 communicates with the outlet of the spent inclined pipe 13, and the spent catalyst outlet of the riser 1 communicates with the spent catalyst inlet of the regenerator 6, so that the spent catalyst first enters the riser 1 through the spent inclined pipe 13, and then enters the regenerator 6 under the action of the lifting medium for regeneration treatment.

[0034] Wherein, the spent slide valve 14 is arranged on the spent inclined pipe 13 to flexibly control the feed amount of the spent catalyst entering the regenerator 6.

[0035] Wherein, the regenerator 6 used in the present disclosure is a conventional selection in the art, and the present application does not make special requirements, for example, the regenerator 6 is provided with a main air distributor 15, a regeneration cyclone separator 16 and a regeneration gas collecting chamber 17, so that the spent catalyst can be contacted with the coking main air 111 in the regenerator 6 for regeneration treatment, and the regenerated catalyst and the regeneration flue gas 112 are obtained.

[0036] Among them, a lifting medium nozzle is set at the bottom of the riser pipe 1, and a light hydrocarbon oil feed nozzle, a dilution steam nozzle and a refining medium nozzle are sequentially set on the descending bed reactor 2 from top to bottom.

[0037] like Figure 1 As shown, the reaction settling tank 4 is equipped with a fully enclosed anti-coking cyclone assembly; the fully enclosed anti-coking cyclone assembly includes a cyclone separator head 21, a sealing cover 22, and a reaction cyclone separator 25; the sealing cover 22 is a sealed cylinder located on the upper part of the stripping section 3; the outlet of the upper part of the sealing cylinder is connected to the inlet of the reaction cyclone separator 25 through a guide tube; the lower part of the sealing cylinder extends downward through the sealing cover plate 23 into the stripping section 3, and the lower part of the sealing cover 22 is provided with a slot 24 so that the inner and outer sides of the sealing cover 22 are connected only through the slot 24; the end of the descending bed reactor 2 is embedded inside the reaction product purification and separation unit, and the end of the descending bed reactor 2 extends into the sealing cylinder, and the cyclone separator head 21 is located at the end outlet of the descending bed reactor 2.

[0038] In this disclosure, the fully enclosed anti-coking cyclone assembly uses a closed cover 22 as a top-closed cylinder. The cylinder of the closed cover 22 includes a lower cylinder, a variable diameter section cylinder, and a top cylinder that are connected sequentially from bottom to top.

[0039] The reaction cyclone separator 25 has two or more stages; the outlet of the guide tube is connected to the inlet of the first-stage reaction cyclone separator so that the oil and gas materials from the reaction products of the descending bed reactor 2 can enter the reaction cyclone separator 25 for separation to obtain high-temperature reaction oil and gas and catalyst materials to be generated; the gas outlet of the last-stage reaction cyclone separator is connected to the inlet of the reaction gas collection chamber 27 so that the reaction oil and gas can enter the reaction gas collection chamber 27 for later use; the catalyst outlet of the reaction cyclone separator 25 extends downward through the material leg through the sealing cover plate 23 to the outer wall of the closed cover 22 and the gas phase space formed by the sealing cover plate 23, so that the catalyst can pass through the slot 24 at the bottom of the closed cover 22 and enter the stripping section 3.

[0040] like Figure 3As shown, the reaction settler 4 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 end outlet of the downer reactor 2 is in communication 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 in communication 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 in the upper part of the stripping section 3 through the sealing cover plate 23; the gas phase space is in communication with the oil-gas collecting pipe 122 through the oil-gas sealing guide pipe 124.

[0041] In the present disclosure, the coarse cyclone 121 and the oil-gas collecting pipe 122 in the coarse cyclone top cyclone sealing direct connection assembly are in sealing communication with the outlet of the riser 1.

[0042] In a preferred embodiment, the reaction cyclone separator 25 is two or more stages; the outlet of the draft tube 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; 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; alternatively, 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; the catalyst outlet of the coarse cyclone 121, the inlet of the oil-gas sealing guide pipe 124 and the catalyst outlet of the reaction cyclone separator 25 extend downward to the gas phase space through legs passing through the sealing cover plate 23.

[0043] In the above-mentioned embodiments, the full-sealing anti-coking cyclone assembly or the coarse cyclone top cyclone sealing direct connection assembly is arranged at the outlet of the downer reactor 2, so that the reaction products obtained by the reaction in the downer reactor 2 can directly enter the reaction cyclone separator 25 under the action of the closed cover 22 or the oil-gas collecting pipe 122, which can avoid the reaction products from staying in the reaction settler 4 with a large volume for too long 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 coking of the reaction products in the reaction settler 4, which leads to the poor anti-fluctuation of the device. In order to further prevent the coking phenomenon in the reaction settler 4, the reaction settler 4 is provided with a full-sealing anti-coking cyclone assembly or a coarse cyclone top cyclone sealing direct connection assembly. 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 header 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.

[0044] 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 provide holes at different positions according to the components used in the reaction settler 4, for example, when the full-closed anti-coking cyclone component is used in the reaction settler 4, the sealing cover plate 23 is tightly combined with the outer wall of the closure hood 22, the inner wall of the reaction settler 4, and the leg outer wall of the reaction cyclone separator 25, or a gap is left therebetween; when the coarse-rotation top-rotation closed direct-connection component is used in the reaction settler 4, the sealing cover plate 23 is tightly combined with the inner wall of the reaction settler 4, 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, or a gap is left therebetween. 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 3 and the reaction settler 4, wherein the diameter of the round holes is 1-100 mm.

[0045] The stripping section 3 includes the stripping section inner member 18, at least one set of stripping steam ring 19 and loosening steam ring 20; the stripping section inner member 18 includes one or more of the herringbone baffle, the ring baffle, the disc umbrella baffle, the packing, and the grid; the stripping steam ring 19 is located in the middle and / or lower part of the stripping section 3; the loosening steam ring 20 is located at the bottom of the stripping section 3; the upper surface and / or the lower surface of the stripping steam ring 19 and the loosening steam ring 20 are provided with steam wear-resistant nozzles.

[0046] The oil-gas quencher 5 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 5, and the top outlet of the reaction settler 4 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. The gas flow 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 5. The upper surface of the stirring steam ring 31 is provided with a plurality of injection holes. The gas flow direction of the injection holes of the stirring steam ring 31 is vertically upward and / or obliquely upward.

[0047] In this embodiment, the quenching medium 109 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 5 to be above 300℃. 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 5 is directly arranged above the reaction settler 4 and integrated with the reaction settler 4, or the oil-gas quencher 5 is separately arranged near the reaction settler 4. In this way, the high-temperature reaction oil-gas can be cooled down in the shortest possible time, avoiding coking of the high-temperature oil-gas. Due to the fact that the gas yield of catalytic cracking of light hydrocarbon oil is much higher than that of conventional catalytic cracking, the total amount of catalyst fines entrained by the reaction oil-gas is relatively large, and the slurry oil yield is much lower than that of conventional catalytic cracking, which may result in a high solid content in the slurry oil. In order to reduce the catalyst content in the quenching medium 109, reduce the wear of equipment and pipelines, and ensure the long-term safe and stable operation of the device, the heat exchange quenching medium 107 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 5. The catalyst removal system includes but is not limited to one or more combinations of filters, cyclones, centrifugal separators, and electric filters.

[0048] As shown in Figure 1 In order to flexibly control the mass flow ratio of the first regenerated catalyst and the second regenerated catalyst, a first regeneration slide valve 12 is arranged on the first regeneration inclined pipe 11, and a second regeneration slide valve 10 is arranged on the second regeneration inclined pipe 8.

[0049] The second regeneration catalyst cooler 7 provided on the second regeneration inclined pipe 8 is a conventional selection in the art, and no special requirement is made in the present application. For example, the second regeneration catalyst cooler 7 can be an electric refrigeration device or a heat exchange device.

[0050] The second aspect of the present disclosure adopts the system of the first aspect of the present disclosure to perform a method for producing low-carbon olefins and aromatic hydrocarbons by catalytic conversion of light hydrocarbon oil. The method comprises: introducing a light hydrocarbon oil feedstock 102 into a downflow bed reactor 2 to contact with the first regeneration catalyst and the second regeneration catalyst to perform a cracking reaction, to obtain a reaction material containing a cracking reaction product and spent catalyst; introducing the reaction material into a reaction settler 4 through an outlet of the downflow bed reactor 2 to perform separation treatment, to obtain a high-temperature reaction oil gas and a spent catalyst material; introducing the spent catalyst material into a stripping section 3 to perform stripping treatment, to obtain spent catalyst; introducing the spent catalyst into a regenerator 6 through a spent inclined pipe 13 to perform regeneration treatment, to obtain a regenerated catalyst; introducing a part of the regenerated catalyst as the first regeneration catalyst into the downflow bed reactor 2 through a first regeneration inclined pipe 11; introducing another part of the regenerated catalyst as the second regeneration catalyst into a second regeneration catalyst cooler 7 through a second regeneration inclined pipe 8, and then into the downflow bed reactor 2 after cooling; introducing the high-temperature reaction oil gas into an oil gas quencher 5 to exchange heat with a quenching medium 109, to obtain a cooled reaction oil gas 110; further separating the low-temperature reaction oil to obtain low-carbon olefins and low-carbon aromatic hydrocarbons, as well as other products and a back-fining medium 101.

[0051] By the above technical scheme, first, the down-flow bed reactor 2 in the gravity field has good gas-solid transfer characteristics, significantly reduces gas-solid axial back mixing, provides a near plug flow environment for light hydrocarbon oil catalytic cracking, and can improve low-carbon olefin and low-carbon aromatic hydrocarbon yield. Second, the reaction system is independently arranged, has a wide application range, is suitable for small and medium-sized devices, and is also suitable for large and super-large devices, and avoids the safety hazard caused by arranging the reactor inside the regenerator 6. Third, the low-temperature second regenerated catalyst is recycled, which can flexibly control the catalyst concentration and activity of the riser 1, significantly increase the catalyst to oil ratio, enhance the catalytic reaction, be beneficial to improve the low-carbon olefin and low-carbon aromatic hydrocarbon yield, and reduce the methane hydrogen and coke yield. Fourth, the reactor is provided with a fully-closed anti-coking cyclone assembly, which significantly shortens the residence time of high-temperature reaction oil gas in the reaction settler 4, effectively avoids coking of high-temperature oil gas in the reaction settler 4, and can reduce non-ideal secondary cracking reaction, improve the yield of target products, and enhance the anti-fluctuation ability of the device. Fifth, the reaction system is provided with a high-temperature reaction oil gas quencher 5, which uses heavy oil as a quenching medium 109, can quickly reduce the temperature of the reaction oil gas, avoids the safety hazard caused by excessive thermal cracking and condensation coking of the reaction oil gas in the pipeline, and can effectively utilize the heat in the high-temperature reaction oil gas. Sixth, under the background of the rapid development of electric vehicles, the present application can maximize the catalytic conversion of fuels such as gasoline, naphtha and kerosene into low-carbon olefins (ethylene + propylene) and low-carbon aromatic hydrocarbons (benzene, toluene, xylene) and other basic chemicals, so that the traditional fuel-type refinery or fuel-lubricating oil-type refinery is transformed into a chemical-type refinery, and the refinery develops and extends from single oil refining to 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 enterprises.

[0052] The light hydrocarbon oil feedstock 102 used in the present disclosure is selected from a light fraction with a distillation range of 20-300°C, 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.

[0053] The catalyst used in the present disclosure is conventionally selected in the art, and the present application does not have special requirements. For example, the regenerated catalyst includes 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 includes 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.

[0054] The mass flow ratio of the regenerated catalysts in the first regenerated inclined pipe 11 and the second regenerated inclined pipe 8 is (1-50):1, preferably (1-20):1, and more preferably (2-5):1.

[0055] In an embodiment, the method further comprises introducing the recycled medium 101, the regenerated catalyst, the light hydrocarbon oil feedstock 102 and the dilution steam 103 into the downer reactor 2, moving upward under the action of the pre-lifting medium 100 and reacting. The main operating conditions of the riser 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.

[0056] The pre-lifting 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.

[0057] In an embodiment, the operating conditions of the stripping section 3 include: the average gas superficial linear velocity 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 catalyst residence time is 0.5-10 min, preferably 1-5 min, and more preferably 2-4 min.

[0058] In an embodiment, the operating conditions of the reaction settler 4 include: the average gas superficial 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 4 is higher than that of the stripping section 3 by 0-20 kPa, preferably 0.02-10 kPa, and more preferably 0.05-5 kPa.

[0059] In an embodiment, the operating conditions of the oil-gas quenching device 5 include: the temperature of the cooled reaction oil gas 110 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.

[0060] In one embodiment, when the full-closed anti-coking cyclone assembly is used in the reaction settler 4, the reaction material is subjected to first separation by the cyclone quick separation head 21 at the outlet of the down-flow bed reactor 2 to obtain the coarsely separated oil gas and the first spent catalyst; the first spent catalyst is allowed to flow downward in the inner space of the closed cover 22 and flows into the stripping section 3; the coarsely separated oil gas is allowed to flow upward along the inner space of the closed cover 22 and enters the reaction cyclone separator 25 for separation to obtain the high-temperature reaction oil gas and the second spent catalyst; after the high-temperature reaction oil gas enters the reaction gas collecting chamber 27 from the gas phase outlet of the reaction cyclone separator 25, it enters the oil gas quenching device; and the second spent catalyst flows from the catalyst outlet of the reaction cyclone separator 25 into the gas phase space formed by the outer wall of the closed cover 22 and the sealing cover plate 23 and finally enters the stripping section 3 through the slot 24.

[0061] When the rough cyclone top cyclone dense closed direct connection assembly is used in the reaction settler 4, the reaction material is subjected to first separation by the rough cyclone 121 to obtain the coarsely separated oil gas and the first spent catalyst; the coarsely separated oil gas is allowed to enter the reaction cyclone separator 25 for separation to obtain the high-temperature reaction oil gas and the second spent catalyst; after the high-temperature reaction oil gas enters the reaction gas collecting chamber 27 from the gas phase outlet of the reaction cyclone separator 25, it enters the oil gas quenching device; and the first spent catalyst flowing from the catalyst outlet of the rough cyclone 121 and the second spent catalyst flowing from the catalyst outlet of the reaction cyclone separator 25 enter the stripping section 3.

[0062] In the above-mentioned embodiments, under the normal operation state of the stripping section 3, the loosening steam 104 and the stripping steam 105 can be allowed to enter for stripping treatment; under the normal operation state of the reaction settler 4, the anti-coking steam 106 can be allowed to enter for anti-coking; and under the normal operation state of the oil gas quenching device 5, the stirring steam 108 can be allowed to enter for stirring treatment. The loosening steam 104, the stripping steam 105, the anti-coking steam 106 and the stirring steam 108 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 480-600°C.

[0063] In one embodiment, in which the mixed C4 and / or mixed C5 and / or cracked naphtha in the reaction product are returned to the down-flow bed reactor 2 for reprocessing; the position where the mixed C4 and / or mixed C5 and / or cracked naphtha enter the down-flow bed reactor 2 is before and / or after the light hydrocarbon oil feed nozzle; and the reprocessing of mixed C4, mixed C5 and cracked naphtha can further improve the yield of low-carbon olefins and low-carbon aromatic hydrocarbons.

[0064] 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 in the examples has the properties shown in Table 2.

[0065] Table 1 Catalyst properties

[0066]

[0067] Table 2 Light hydrocarbon oil raw material properties

[0068]

[0069] Example 1

[0070] 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

[0071] Taking a light hydrocarbon oil raw material 102 (a mixture of straight-run naphtha, straight-run kerosene and coking naphtha) with a feedstock amount of 0.9 million tons / year as an example, the method for catalytically converting the light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons includes:

[0072] The light hydrocarbon oil raw material 102 is preheated to 300°C and then enters the downflow bed reactor 2 to contact the regenerated catalyst to perform a cracking reaction, to obtain a reaction material containing a cracking reaction product and spent catalyst.

[0073] The reaction material is subjected to a first separation by a cyclone quick separation head 21 at the outlet of the downflow bed reactor 2 to obtain a crude separation 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 3; the crude separation oil gas flows upward along the inner wall of the closed cover 22 and enters the reaction cyclone separator 25 through the flow guide cylinder to be separated, to obtain the high-temperature reaction oil gas and the second spent catalyst; the high-temperature reaction oil gas enters the reaction gas collection chamber 27 from the gas phase outlet of the reaction cyclone separator 25, and the second spent catalyst flows 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 enters the stripping section 3 through the slot 24.

[0074] ​The high-temperature reaction oil gas is made to enter the oil gas quenching device 5 from the reaction gas collecting chamber 27, and the high-temperature reaction oil gas is cooled to 350 DEG C by using 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 down-flow bed reactor 2 for reprocessing, so as 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 3 downward, and the spent catalyst is made to enter the regeneration device through the spent catalyst inclined pipe 13 after the oil gas entrained is stripped, and the regenerated catalyst obtained is made to enter the riser 1 through the first regenerated catalyst inclined pipe 11 as the first regenerated catalyst, and is made to return to the down-flow bed reactor 2 through the lifting medium for circulation; another part of the regenerated catalyst is made to enter the second regenerated catalyst cooler 7 as the second regenerated catalyst after being cooled, and is made to enter the riser 1, and is made to return to the down-flow bed reactor 2 through the lifting medium for circulation.

[0075] The operation conditions of the method are shown in Table 3; and the product distribution of the device is shown in Table 4.

[0076] Example 2

[0077] The system for catalytically converting the light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons used in this example is shown in Figure 2 ;

[0078] The method for catalytically converting the light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons is the same as that in Example 1, and the difference is that the reaction material is made to pass through the rough spin 121 for the first separation to obtain the rough separation oil gas and the first spent catalyst; the rough separation oil gas is made to enter the reaction cyclone separator 25 for separation to obtain the high-temperature reaction oil gas and the second spent catalyst; the high-temperature reaction oil gas is made to enter the reaction gas collecting chamber 27 from the gas phase outlet of the reaction cyclone separator 25; and the first spent catalyst flowing out from the catalyst outlet of the rough spin 121 and the second spent catalyst flowing out from the catalyst outlet of the reaction cyclone separator 25 enter the stripping section 3.

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

[0080] Example 3

[0081] The system for catalytically converting the light hydrocarbon oil to produce low-carbon olefins and aromatic hydrocarbons used in this example is shown in Figure 3 ;

[0082] The process for catalytic conversion of light hydrocarbon oil to produce low carbon olefins and aromatics is the same as in Example 1, except that the spent catalyst is made to enter the riser 1 through the spent catalyst inclined pipe 13 and enter the regenerator 6 for coking regeneration under the action of the lifting medium; the first regenerated catalyst is made to enter the down-flow bed reactor 2 through the first regenerated inclined pipe 11 for recycling; and the second regenerated catalyst is made to enter the down-flow bed reactor 2 through the second regenerated inclined pipe 8 for recycling.

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

[0084] Example 4

[0085] The system for catalytic conversion of light hydrocarbon oil to produce low carbon olefins and aromatics used in this example is shown in Figure 4

[0086] The process for catalytic conversion of light hydrocarbon oil to produce low carbon olefins and aromatics is the same as in Example 2, except that the spent catalyst is made to enter the riser 1 through the spent catalyst inclined pipe 13 and enter the regenerator 6 for coking regeneration under the action of the lifting medium; the first regenerated catalyst is made to enter the down-flow bed reactor 2 through the first regenerated inclined pipe 11 for recycling; and the second regenerated catalyst is made to enter the down-flow bed reactor 2 through the second regenerated inclined pipe 8 for recycling.

[0087] The operating conditions of the process are shown in Table 3; and the product distribution of the device is shown in Table 4.

[0088] Comparative Example 1

[0089] The process for catalytic conversion of light hydrocarbon oil to produce low carbon olefins and aromatics is the same as in Example 1, except that the spent catalyst is made to enter the riser 1 through the spent catalyst inclined pipe 13 and enter the regenerator 6 for coking regeneration under the action of the lifting medium; the first regenerated catalyst is made to enter the down-flow bed reactor 2 through the first regenerated inclined pipe 11 for recycling; and the second regenerated catalyst is made to enter the down-flow bed reactor 2 through the second regenerated inclined pipe 8 for recycling.

[0090] The operating conditions of the process are shown in Table 3; and the product distribution of the device is shown in Table 4.

[0091] Table 3 Operating conditions

[0092] ​

[0093]

[0094] Table 4 Distribution of device products

[0095]

[0096] 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, the risk of coking of high-temperature oil gas in the reaction settler can be reduced, and the yield of the target product can be improved.

[0097] The preferred embodiments of the present disclosure are described in detail above in combination with 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.

[0098] 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, the present disclosure will not further describe various possible combination manners.

[0099] In addition, various different embodiments of the present disclosure can also be combined in any manner, as long as it does not deviate from the idea of the present disclosure, and it should also be considered as disclosed by the present disclosure.

Claims

1. A downflow bed reaction system for the catalytic conversion of light hydrocarbon oils to produce lower carbon olefins and aromatic hydrocarbons, characterized by, The system comprises a down-flow bed reactor (2), a reaction product purification separation unit, an oil gas quencher (5) and a regenerator (6); the reaction product purification separation unit and the oil gas quencher (5) are coaxially arranged and the oil gas quencher (5) is arranged at the top of the reaction product purification separation unit; the reaction product purification separation unit comprises a stripping section (3) and a reaction settler (4) from bottom to top in sequence, and the stripping section (3) and the reaction settler (4) are separated by a sealing cover plate (23); the down-flow bed reactor (2) and the reaction product purification separation unit are arranged side by side; The stripping section (3) comprises a spent catalyst outlet; the down-flow bed reactor (2) comprises a first regenerated catalyst inlet and a second catalyst inlet; the regenerator (6) comprises a spent catalyst inlet, a first regenerated catalyst outlet and a second regenerated catalyst outlet; The spent catalyst inlet of the regenerator (6) is in communication with the spent catalyst outlet of the stripping section (3) through a spent catalyst inclined pipe (13); the first regenerated catalyst outlet of the regenerator (6) is in communication with the first regenerated catalyst inlet of the down-flow bed reactor (2) through a first regenerated catalyst inclined pipe (11); the second regenerated catalyst outlet of the regenerator (6) is in communication with the second regenerated catalyst inlet of the down-flow bed reactor (2) through a second regenerated catalyst inclined pipe (8); wherein the second regenerated catalyst inclined pipe (8) is provided with a second regenerated catalyst cooler (7).

2. The downflow bed reaction system according to claim 1, wherein The reaction settler (4) 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 (3); the outlet at the upper part of the sealing cylinder is in communication 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 (3) through the sealing cover plate (23), and the lower part of the closed cover (22) is provided with a slot (24) so that the inner side and the outer side of the closed cover (22) are only in communication through the slot (24); the end of the down-flow bed reactor (2) is embedded inside the reaction product purification separation unit, and the end of the down-flow bed reactor (2) extends into the sealing cylinder, and the cyclone quick separation head (21) is arranged at the end outlet of the down-flow bed reactor (2); or, The reaction settler (4) 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 end outlet of the downer reactor (2) 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 in the upper part of the stripping section (3) through the sealing cover plate (23); the gas phase space is communicated with the oil gas collecting pipe (122) through the oil gas sealing guide pipe (124).

3. The downflow bed reaction system according to claim 2, wherein The reaction settler (4) is provided with a reaction gas collecting chamber (27); the outlet of the reaction gas collecting chamber (27) is communicated with the top outlet of the reaction settler (4); The reaction cyclone separator (25) is at least two stages; 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 the legs 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 sealing guide pipe (124) and the catalyst outlet of the reaction cyclone separator (25) extend downward to the gas phase space through the legs passing through the sealing cover plate (23).

4. The downflow bed reaction system according to claim 1, wherein The downer reactor system further comprises an equal-diameter cylindrical riser (1); The lower part of the riser (1) is provided with the first regenerated catalyst inlet for being communicated with the outlet of the first regenerated inclined pipe (11), and the second regenerated catalyst inlet arranged above the first regenerated catalyst inlet for being communicated with the outlet of the second regenerated inclined pipe (8); or, The lower part of the riser (1) is provided with a spent catalyst inlet, and the upper part is provided with a spent catalyst outlet; the spent catalyst inlet of the riser (1) is communicated with the outlet of the spent inclined pipe (13), and the spent catalyst outlet of the riser (1) is communicated with the spent catalyst inlet of the regenerator (6).

5. The downflow bed reaction system according to claim 1, wherein The stripping section (3) comprises a stripping section internal component (18), at least one group of stripping steam rings (19) and loosening steam rings (20); The stripping section inner member (18) comprises one or more of herringbone baffle, ring baffle, disc umbrella baffle, packing and grid; the stripping steam ring (19) is located in the middle and / or lower part of the stripping section (3); the loosening steam ring (20) is located in the bottom of the stripping section (3); the upper surface and / or lower surface of the stripping steam ring (19) and the loosening steam ring (20) is provided with steam wear-resistant nozzles.

6. The downflow bed reaction system according to claim 1, wherein The oil-gas quenching device (5) comprises an oil-gas distributor (28), a quenching 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 quenching device (5), and the top outlet of the reaction settler (4) is communicated with the inlet of the oil-gas distributor (28); The quenching baffle (29) is located above the oil-gas distributor (28); the quenching baffle (29) has 1-20 layers; The quenching medium distributor (30) is located at the upper part of the quenching baffle (29); the lower surface of the quenching medium distributor (30) is provided with 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 quenching device (5); the upper surface of the stirring steam ring (31) is provided with injection holes, and the airflow direction of the injection holes of the stirring steam ring (31) is vertically upward and / or obliquely upward.

7. A process for the catalytic conversion of light hydrocarbon oils to lower olefins and aromatic hydrocarbons using the downflow bed reaction system according to any one of claims 1 to 6, characterized in that, The method comprises: making the light hydrocarbon oil raw material enter the down-flow bed reactor (2) to contact with the first regenerated catalyst and the second regenerated catalyst to carry out cracking reaction, to obtain reaction material containing cracking reaction product and spent catalyst; making the reaction material enter the reaction settler (4) through the outlet of the down-flow bed reactor (2) to carry out separation treatment, to obtain high-temperature reaction oil gas and spent catalyst material; making the spent catalyst material enter the stripping section (3) to carry out stripping treatment, to obtain spent catalyst; making the spent catalyst enter the regenerator (6) through the spent catalyst inclined pipe (13) to carry out regeneration treatment, to obtain regenerated catalyst; making part of the regenerated catalyst as the first regenerated catalyst enter the down-flow bed reactor (2) through the first regenerated catalyst inclined pipe (11); making another part of the regenerated catalyst as the second regenerated catalyst enter the second regenerated catalyst cooler (7) to cool after entering the down-flow bed reactor (2) through the second regenerated catalyst inclined pipe (8); making the high-temperature reaction oil gas enter the oil-gas quenching device (5) to exchange heat with quenching medium, to obtain cooled reaction oil gas; making the cooled reaction oil gas further separate, to obtain low-carbon olefin and low-carbon aromatic hydrocarbon.

8. The method of claim 7, wherein, The light hydrocarbon oil raw material is selected from light fraction with 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 meso-microporous zeolite; the content of the mesoporous zeolite is 10-90% by weight and the content of the meso-microporous 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℃.

9. The method of claim 8, wherein, The light hydrocarbon oil feedstock 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 cracked heavy oil, catalytic cracking slurry oil, catalytic cracking slurry oil, coking slurry oil, atmospheric residue and vacuum residue.

10. The method of claim 7, 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 (3) include: average gas superficial linear velocity of 0.05-1 m / s and average catalyst residence time of 0.5-10 min; The operating conditions of the oil-gas quenching device (5) include: outlet reaction oil-gas temperature of 200-550℃, bottom liquid temperature of 200-500℃ and bottom liquid residence time of 0-15 min; The mass flow rate ratio of the regenerated catalyst through the first regenerated inclined pipe (11) to the second regenerated inclined pipe (8) is (1-50):

1.

11. The method of claim 7, wherein, The reaction settler (4) 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); or, The reaction settler (4) is provided with a coarse cyclone top cyclone closed direct connection assembly; the coarse cyclone top cyclone closed direct connection assembly comprises a coarse cyclone (121), an oil-gas collecting pipe (122), an oil-gas closed guide pipe (124) and a reaction cyclone separator (25). The method further comprises: subjecting the reaction material to first separation by a cyclone quick separation head (21) at the outlet of the downflow bed reactor (2) to obtain a 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 (3); 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; subjecting the high-temperature reaction oil gas to enter an oil gas quenching device (5) from the gas phase outlet of the reaction cyclone separator (25), and subjecting the second spent catalyst to flow into a 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 (3) through a slot (24); or, The method further comprises: subjecting the reaction material to first separation by a cyclone (121) to obtain a crude separation oil gas and first spent catalyst; subjecting the crude separation oil gas to enter a 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 an oil gas quenching device (5) 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 cyclone (121) and the second spent catalyst flowing out from the catalyst outlet of the reaction cyclone separator (25) to enter the stripping section (3).

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