A method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed

Abstract

The present invention relates to a method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed, the method comprising: S1, in a hydrogen atmosphere, contacting an LCO raw material with an aromatization catalytic cracking catalyst at the lower part of a circulating turbulent fluidized bed reactor and performing a catalytic cracking reaction in a co-current direction to obtain a reaction mixture; S2, separating the reaction mixture to obtain product oil and gas containing light olefins and aromatics and a catalyst to be produced. The method of the present invention can effectively improve the yield of light olefins and aromatics.

Description

Technical Field

[0001] The invention relates to a method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed. Background Art

[0002] With the upgrading of gasoline and diesel quality and the change in demand structure, the domestic consumption of diesel and gasoline ratio continues to decline, and the problem of diesel surplus in refineries will become increasingly prominent. Low-carbon olefins and aromatics are important organic chemical raw materials, with strong domestic market demand and high external dependence. On the one hand, there is an overcapacity of domestic refining capacity, and on the other hand, there is a shortage of organic chemical raw materials. Therefore, the transformation of refining to chemical industry has become an inevitable trend.

[0003] Catalytic cracking diesel (LCO) is rich in aromatics and is a potential ideal raw material for producing aromatics. Monocyclic aromatics are crackable and can be directly catalytically cracked to produce aromatics. Polycyclic aromatics are easily saturated to monocyclic aromatics after hydrogenation. Therefore, it is expected to increase aromatics production capacity by hydrogenating LCO and combining it with catalytic cracking technology.

[0004] At present, the catalytic cracking process for producing low-carbon olefins and aromatics mainly adopts a riser reactor, and the most widely used is the DCC technology developed by Sinopec Petrochemical Research Institute. The particle concentration of the riser reactor bed is low, usually less than 10% (Bi H, et al. Chemical Engineering Science, 2000, 55: 4789-4825.), and it is difficult to achieve a high conversion intensity by relying solely on the riser reactor, so this technology uses a reactor type of riser plus bed to strengthen the cracking depth. Patents CN101362963, CN101747928, CN1667089, etc. rely on DCC technology to disclose a method of using heavy raw materials to catalytically crack and produce more propylene and aromatics. By refining the distillate oil such as the difficult-to-crack raw materials or the circulating cracking raw materials, the propylene yield can reach more than 40, and BTX can be extracted from the aromatic-rich fraction by aromatic extraction technology. The above patents all use a riser reactor, however, the riser reactor itself has defects such as low bed particle concentration, radial non-uniform annular core distribution and large axial back mixing, thus affecting the conversion rate and selectivity of the catalytic cracking reaction.

[0005] In addition, although the above patents are suitable for the production of light olefins by saturated cracking in LCO, they are not suitable for the dealkylation reaction of aromatics with high reaction activation energy barriers. The yield of light olefins and aromatics in the prior art is low, while the yield of coke is high. In order to meet the growing demand for organic chemical raw materials such as light olefins and aromatics and solve the problem of excess fuel production capacity, it is very necessary to develop a conversion method for producing light olefins and aromatics by catalytic cracking of LCO. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed. The method of the present invention has a higher yield of light olefins and aromatics.

[0007] In order to achieve the above object, the present invention provides a method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed, the method comprising:

[0008] S1. In a hydrogen atmosphere, contacting an LCO feedstock with an aromatization catalytic cracking catalyst at the lower part of a circulating turbulent fluidized bed reactor and performing a catalytic cracking reaction in a co-current manner to obtain a reaction mixture;

[0009] S2. Separating the reaction mixture to obtain product oil and gas containing light olefins and aromatics and a catalyst to be produced.

[0010] Optionally, the conditions of the catalytic cracking reaction include: a reaction temperature of 500-650° C., a reaction pressure of 0.1-2.0 MPa, a hydrogen partial pressure of 0.1-2.0 MPa, a catalyst-oil weight ratio of 5-50, and a residence time of the LCO feedstock of 4-20 seconds.

[0011] Optionally, the conditions of the catalytic cracking reaction include: the reaction temperature is 525-625° C., the reaction pressure is 0.4-1.2 MPa, the hydrogen partial pressure is 0.2-1.0 MPa, the catalyst-oil weight ratio is 8-30, and the residence time of the LCO feedstock is 4-20 seconds.

[0012] Optionally, the particle concentration of the aromatization catalytic cracking catalyst in the circulating turbulent fluidized bed reactor is 20-35%, and the circulation rate is 100-800 kg / m 2 s, and the fluidizing gas velocity is 0.1-15m / s.

[0013] Optionally, the method further comprises: stripping and charring the spent catalyst, and returning at least a portion of the regenerated catalyst to the circulating turbulent fluidized bed reactor of step S1 to be used as the aromatization catalytic cracking catalyst.

[0014] Optionally, the conditions for the char regeneration include: a temperature of 550-800° C., a pressure of 0.2-2.0 MPa, and a time of 2-15 minutes.

[0015] Optionally, the separation is performed in a rapid separation device.

[0016] Optionally, the method further comprises: preheating the LCO raw material before introducing it into the downcomer reactor, wherein the temperature of the preheated LCO raw material is 100-300°C.

[0017] Optionally, the hydrogen atmosphere contains hydrogen and / or dry gas.

[0018] Optionally, the aromatization catalytic cracking catalyst contains 1-60 wt% of zeolite, 5-95 wt% of inorganic oxide, 0-80 wt% of clay and 0-20 wt% of active metal component on a dry basis and based on the total weight of the aromatization catalytic cracking catalyst;

[0019] The zeolite contains 40-100 wt% of medium pore zeolite and 0-60 wt% of large pore zeolite, calculated on a dry basis and based on the total weight of the zeolite.

[0020] Optionally, the large-pore zeolite is selected from one or more of high-silicon Y, rare earth Y, rare earth hydrogen Y and ultra-stable Y, and the medium-pore zeolite is selected from ZSM series zeolite and / or ZRP zeolite;

[0021] The inorganic oxide is selected from silicon dioxide and / or aluminum oxide;

[0022] The clay is selected from one or more of kaolin, montmorillonite, diatomite, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite;

[0023] The active metal component contains one or more selected from Fe, Co, Ni, Cu, Zn and rare earth metals.

[0024] Compared with the prior art, the method of the present invention has the following technical effects:

[0025] (1) It has strong adaptability to raw materials. It is not only suitable for light catalytic cracking raw materials such as LCO, but also suitable for the deep catalytic cracking process of inferior heavy raw materials with high density and low hydrogen content.

[0026] (2) The present invention adopts a circulating turbulent fluidized bed reactor, which has a high gas-solid flux, uniform axial and radial distribution, and extremely small axial backmixing, so it can help improve the yield of low-carbon olefins and aromatics at high particle size and have high product selectivity.

[0027] (3) The presence of hydrogen and the use of an aromatization catalyst facilitate the dealkylation reaction of LCO aromatics, which can increase the production of aromatics. At the same time, the presence of hydrogen in the reaction atmosphere can reduce the hydrocarbon partial pressure, thereby increasing the yield of light olefins.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 It is a structural schematic diagram of a system for processing LCO to prepare light olefins and aromatics according to the present invention.

[0031] Description of Reference Numerals

[0032] 1. Hydrogen-containing medium 2. Inlet distribution plate 3. Regeneration slide valve

[0033] 4. Oil inlet nozzle 5. Circulating turbulent fluidized bed reactor 6. Cyclone separator

[0034] 7. Stripper 8. Product oil and gas discharge pipeline 9. Stripping steam

[0035] 10. Waiting slide valve 11. Regenerator 12. Cyclone separator

[0036] 13. Flue gas outlet pipeline 14. Regeneration medium DETAILED DESCRIPTION

[0037] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0038] The present invention provides a method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed, the method comprising:

[0039] S1. In a hydrogen atmosphere, contacting an LCO feedstock with an aromatization catalytic cracking catalyst at the lower part of a circulating turbulent fluidized bed reactor and performing a catalytic cracking reaction in a co-current manner to obtain a reaction mixture;

[0040] S2. Separating the reaction mixture to obtain product oil and gas containing light olefins and aromatics and a catalyst to be produced.

[0041] The inventors of the present invention have found through a large number of literature surveys and experimental studies that high temperature, large catalyst-oil ratio and hydrogen are conducive to the catalytic cracking of LCO to produce light olefins and aromatics. Conventional methods for producing light olefins and aromatics are mainly based on riser reactors, with low particle concentration in the bed (usually less than 10%), uneven radial and axial distribution, and severe backmixing, which affects the selectivity of intermediates such as propylene, and the dealkylation reaction of aromatics is poor, which affects the yield of aromatics. In the method of the present invention, LCO raw materials and catalyst particles flow through a circulating turbulent fluidized bed, and the circulating turbulent fluidized bed reactor can achieve continuous operation, and at the same time has a high gas-solid flux, uniform axial and radial distribution, and extremely small axial backmixing, which is conducive to improving the yield of intermediates such as propylene. The reaction also uses a catalyst with aromatization, and with the reaction atmosphere of hydrogen, the reaction conversion rate can be improved and the yield of olefins and aromatics can be increased.

[0042] According to the present invention, catalytic cracking is well known to those skilled in the art. In a specific embodiment of the present invention, the conditions of the catalytic cracking reaction include: reaction temperature of 500-650°C, preferably 525-625°C, reaction pressure of 0.1-2.0MPa, preferably 0.4-1.2MPa, hydrogen partial pressure of 0.1-2.0MPa, preferably 0.2-1.0MPa, catalyst-to-oil weight ratio of 5-50, preferably 8-30, and residence time of the LCO feedstock of 4-20 seconds, preferably 4-10 seconds. Wherein, the reaction temperature refers to the outlet temperature of the circulating turbulent fluidized bed reactor. When the catalytic cracking reaction is carried out under the above-mentioned reaction conditions of hydrogenation, high temperature, and large catalyst-to-oil ratio, and in combination with the reaction atmosphere of hydrogenation, the reaction conversion rate can be further improved, and the yield of olefins and aromatics can be increased.

[0043] In order to ensure that the bed of the circulating turbulent fluidized bed reactor is turbulently fluidized, in a specific embodiment of the present invention, the particle concentration of the aromatization catalytic cracking catalyst in the circulating turbulent fluidized bed reactor is 20-35%, preferably 22-30%, and the circulation rate is 100-800 kg / m 2 s, preferably 200-500kg / m 2 s, the fluidizing gas velocity may be between bubbling fluidization and fast fluidization in the catalyst bed. Since different particles have different characteristic fluidizing gas velocities, the fluidizing gas velocity may be, for example, 0.1-15 m / s, preferably 0.5-10 m / s.

[0044] In a preferred embodiment of the present invention, the method further comprises: selectively stripping and charring the regenerated catalyst, returning at least a portion of the obtained regenerated catalyst to the circulating turbulent fluidized bed reactor of step S1, and using it as the aromatization catalytic cracking catalyst. The methods of stripping and charring regeneration are well known to those skilled in the art and will not be described in detail herein. The medium used for stripping can be water vapor, and the weight ratio of water vapor to the regenerated catalyst can be selected as required, for example, it can be 0.1-0.3. The conditions for charring regeneration include: temperature of 550-800°C, pressure of 0.2-2.0MPa, time of 2-15 minutes, and the regeneration medium can be air. In one embodiment, the temperature of charring regeneration refers to the outlet temperature of the regenerator.

[0045] In a specific embodiment of the present invention, in step S2, separation is performed in a rapid separation device. In the method of the present invention, by allowing the reaction mixture obtained by the catalytic cracking reaction in the circulating turbulent fluidized bed reactor to enter the rapid separation device for separation, the excessive cracking reaction of the reaction raw materials can be effectively suppressed and the selectivity of the reaction can be improved.

[0046] In a specific embodiment of the present invention, the method further comprises: preheating the LCO raw material before introducing it into the downer reactor, wherein the temperature of the preheated LCO raw material is 100-300°C, preferably 200-300°C.

[0047] According to the present invention, the hydrogen atmosphere refers to an atmosphere containing hydrogen, and preferably, the hydrogen atmosphere contains hydrogen and / or dry gas. In a specific embodiment of the present invention, a gas containing hydrogen is introduced into the circulating turbulent fluidized bed reactor from the lower part of the circulating turbulent fluidized bed reactor to form a hydrogen atmosphere, and in this manner, the gas containing hydrogen also serves as a fluidizing gas.

[0048] In a specific embodiment of the present invention, the aromatization catalytic cracking catalyst contains 1-60 wt% of zeolite, 5-95 wt% of inorganic oxide, 0-80 wt% of clay and 0-20 wt% of active metal component, calculated on a dry basis and based on the total weight of the aromatization catalytic cracking catalyst; preferably, the aromatization catalyst contains 20-50 wt% of zeolite, 30-70 wt% of inorganic oxide, 10-45 wt% of clay and 1-15 wt% of active metal component; calculated on a dry basis and based on the total weight of the zeolite, the zeolite contains 40-100 wt% of medium-pore zeolite and 0-60 wt% of large-pore zeolite.

[0049] According to the present invention, the large-pore zeolite can be selected from Y series zeolites, such as one or more of high-silicon Y, rare earth Y (REY), rare earth hydrogen Y (REHY) and ultra-stable Y, and the medium-pore zeolite can be selected from ZSM series zeolites and / or ZRP zeolites. Wherein, ZSM series zeolites can include but are not limited to one or two of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other zeolites of similar structure. In addition, zeolite can also include BETA type molecular sieves with both large-pore structure and medium-pore structure. The present invention does not limit the specific type of inorganic oxide contained in the aromatization catalyst, and the inorganic oxide conventionally used as a binder by those skilled in the art can be used, for example, the inorganic oxide can be selected from silicon dioxide and / or aluminum oxide, preferably, the inorganic oxide is a mixture of silicon dioxide and aluminum oxide, and the content of silicon dioxide in the mixture can be 45-95% by weight on a dry weight basis. The present invention does not specifically limit the type of clay contained in the aromatization catalyst. Clay conventionally used as a carrier by those skilled in the art can be used. For example, the clay can be selected from one or more of kaolin, montmorillonite, diatomaceous earth, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite. According to the present invention, the active metal component contained in the aromatization catalyst can be a metal with a dehydrogenation effect, preferably a transition metal element of the fourth period and the fifth period, and can include but is not limited to one or more of Fe, Co, Ni, Cu, Zn and rare earth metals. Preferably, the active metal component exists in the form of metal oxides and / or metal hydroxides.

[0050] like Figure 1 As shown, in a preferred embodiment of the present invention, the following method is used to process LCO to prepare light olefins and aromatics:

[0051] The aromatization catalytic cracking catalyst enters the bottom of the circulating turbulent fluidized bed reactor 5 through the regeneration slide valve 3, is fluidized by the hydrogen-containing medium 1, and flows upward through the inlet distribution plate 2. After being preheated, the LCO feed oil enters the bottom of the circulating turbulent fluidized bed reactor 5 through the oil inlet nozzle 4 to mix and contact with the aromatization catalytic cracking catalyst, and flows upward into the circulating turbulent fluidized bed reactor 5 for catalytic cracking reaction. The obtained reaction mixture is separated by the cyclone separator 6 at the top of the circulating turbulent fluidized bed reactor, and the separated product oil and gas enter the fractionation unit through the product oil and gas discharge pipeline 8. The catalyst to be regenerated separated by the cyclone separator 6 enters the stripper 7 for stripping. After being stripped by the stripping steam 9, the catalyst to be regenerated enters the regenerator 11 through the regeneration slide valve 10, and is regenerated by burning through the regeneration medium 14. The flue gas generated by the regeneration is separated by the cyclone separator 12 and discharged from the flue gas outlet pipeline 13. The regenerated catalyst enters the reactor from the regeneration slide valve 3 for the next cycle.

[0052] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0053] The catalyst used in the examples was prepared by the following method:

[0054] (1) Dissolve 20 kg of ammonium chloride in 1000 kg of water, add 100 kg (dry basis) of crystallized DASY zeolite (produced by the catalyst plant of Qilu Petrochemical Company, 2.445-2.448 nm, rare earth content RE 2 O 3 2.0 wt%), exchanged at 90°C for 0.6h, filtered to obtain a filter cake; 40 kg Cu(NO 3 ) 2 6H 2 O was dissolved in 200 kg of water, mixed with the filter cake, impregnated and dried; then calcined at 560 ° C for 2 hours to obtain a copper-containing macroporous zeolite, whose elemental analysis chemical composition is 0.1 Na 2 O.5.1Al 2 O 3 ·18.2CuO·3.8RE 2 O 3 88.1SiO 2 .

[0055] (2) Dissolve 20 kg of ammonium phosphate in 600 kg of water and stir evenly. Add 50 kg of MFI structured mesoporous ZRP-1 zeolite (industrial product of the catalyst plant of Qilu Petrochemical Company, SiO 2 / Al 2 O 3 30), immersed and stirred at 60°C for 3h, and filtered to obtain a filter cake; the molecular sieve filter cake was dried at 120°C, and then calcined at 550°C for 1 hour to obtain a phosphorus-containing medium-porous zeolite.

[0056] (3) 80 kg of halloysite (industrial product of Suzhou Clay Company, solid content 71.6 wt%) was slurried with 250 kg of decationized water, and then 50 kg of pseudo-boehmite (industrial product of Shandong Aluminum Plant, solid content 63 wt%) was added, and the pH value was adjusted to 2-4 with hydrochloric acid, stirred evenly, and aged at 60-70 ° C for 1 hour, maintaining the pH value at 2-4, and the temperature was lowered to below 60 ° C, and 40 kg of aluminum sol (product of Qilu Petrochemical Company Catalyst Plant, Al 2 O 3 The mixture was stirred for 40 minutes to obtain a mixed slurry.

[0057] (4) The copper-containing macroporous zeolite (33.8 kg on dry basis) prepared in step (1) and the phosphorus-containing MFI structure medium-pore ZRP-1 zeolite (15.0 kg on dry basis) prepared in step (2) are added to the mixed slurry obtained in step (3), stirred evenly, and 5 g of commercial alumina adhesive is added, mixed and placed in the adhesive, and an appropriate amount of water is added, stirred evenly, and placed in the air for 5 hours, and then placed in the air for 5 hours, spray-dried and formed, and dried in a drying oven at 120° C. for 3 hours, and then washed with diammonium phosphate solution (phosphorus content is 1% by weight) to remove free Na + The catalyst was dried again and recorded as CAT-1. The composition of the catalyst was 18.9 wt% DASY zeolite, 12.0 wt% MFI structure medium pore zeolite, 1.9 wt% copper oxide, 0.8 wt% phosphorus pentoxide, 22.8 wt% pseudo-boehmite, 6.0 wt% aluminum sol and the balance kaolin. The properties are listed in Table 2.

[0058] The DMMC-2 balance agent used in Comparative Example 1 was purchased from the catalyst plant of Qilu Petrochemical Company. It mainly contains 48.1% by weight of aluminum oxide, 46% by weight of silicon oxide, and 1.51% by weight of phosphorus pentoxide. The properties are shown in Table 2.

[0059] Example 1

[0060] This embodiment Figure 1 The system shown processes LCO in a hydrogen-based operation mode, uses the LCO in Table 1 as the feedstock oil, and uses a CAT-1 catalyst with a catalyst activity of 64.

[0061] The LCO preheating temperature is 200°C, and the conditions for the catalytic cracking reaction are: the outlet temperature of the circulating turbulent fluidized bed reactor is 550°C, the reaction pressure is 0.4MPa, the hydrogen partial pressure is 0.2MPa, the catalyst-oil weight ratio is 20, and the residence time is 4 seconds.

[0062] The weight ratio of water vapor to spent catalyst during the stripping process of spent catalyst is 0.15.

[0063] The conditions for char regeneration are: the outlet temperature of the regenerator is 750°C, the pressure is 0.6MPa, and the regeneration medium is air.

[0064] The particle concentration of CAT-1 catalyst in the circulating turbulent fluidized bed reactor is 25% and the circulation rate is 200 kg / m 2 s, and the fluidizing gas velocity is 0.8 m / s.

[0065] The aromatization catalytic cracking catalyst enters the circulating turbulent fluidized bed reactor 5 through the slide valve 3 to be regenerated, and enters the circulating turbulent fluidized bed reactor after fluidization in the hydrogen-containing fluidized medium 1. After preheating, the LCO feed oil enters the bottom of the circulating turbulent fluidized bed reactor through the oil inlet nozzle 4 to mix and contact with the aromatization catalytic cracking catalyst, and flows upward to the circulating turbulent fluidized bed reactor for catalytic cracking reaction. The obtained reaction mixture is separated by a cyclone separator 6 at the top of the circulating turbulent fluidized bed, and the separated product oil and gas enter the fractionation unit through the product oil and gas discharge pipeline 8. The catalyst to be regenerated separated by the cyclone separator 6 is stripped in the stripper. After being stripped by the stripping steam 9, the catalyst enters the regenerator 11 through the slide valve 10 to be regenerated by charring, and the flue gas generated by the regeneration is separated by the cyclone separator 12 and discharged from the flue gas outlet pipeline 13. The regenerated catalyst enters the reactor from the regeneration slide valve 3 for the next cycle. The operating conditions and products are listed in Table 3.

[0066] Example 2

[0067] LCO was processed in the same manner as in Example 1, except that the conditions for the catalytic cracking reaction were as follows: the outlet temperature of the circulating turbulent fluidized bed reactor was 600° C., the reaction pressure was 0.6 MPa, the hydrogen partial pressure was 0.4 MPa, the catalyst-oil weight ratio was 20, and the residence time was 4 seconds.

[0068] Example 3

[0069] LCO was processed in the same manner as in Example 1, except that the conditions for the catalytic cracking reaction were as follows: the outlet temperature of the circulating turbulent fluidized bed reactor was 500° C., the reaction pressure was 0.6 MPa, the hydrogen partial pressure was 0.1 MPa, the catalyst-oil weight ratio was 10, and the residence time was 2 seconds.

[0070] Example 4

[0071] The LCO was processed in the same manner as in Example 1, except that the particle concentration of the CAT-1 catalyst in the circulating turbulent fluidized bed reactor was 10% and the circulation rate was 100 kg / m 2 s, and the fluidizing gas velocity is 1.1 m / s.

[0072] Comparative Example 1

[0073] This comparative example adopts the existing riser catalytic cracking process, processes LCO in a small riser reactor, adopts a non-hydrogen operation mode, uses a DMMC-2 balance agent as the catalyst, uses nitrogen as the fluidizing gas, and the feedstock oil is the same as in Example 1. Among them, the LCO preheating temperature is 200°C, and the conditions for the catalytic cracking reaction are: the reaction outlet temperature is 550°C, the reaction pressure is 0.2MPa, the catalyst-oil weight ratio is 10, and the residence time is 1.5 seconds. The conditions for char regeneration are: the regenerator outlet temperature is 700°C, the regenerator pressure is 0.6MPa, the regeneration medium is air, and the weight ratio of water vapor to the catalyst to be regenerated is 0.15. The specific operating conditions and product distribution are listed in Table 3.

[0074] Comparative Example 2

[0075] This comparative example adopts the existing riser catalytic cracking process, processes LCO in a small riser reactor, adopts the hydrogenation operation mode, the catalyst is DMMC-2 balance agent, and the feedstock oil is the same as Example 1. Among them, the preheating temperature of hydrogenated LCO is 200°C, and the conditions of the catalytic cracking reaction are: the reaction outlet temperature is 600°C, the reaction pressure is 0.6MPa, the hydrogen partial pressure is 0.4MPa, the catalyst-oil weight ratio is 10, and the residence time is 1.5 seconds. The conditions for char regeneration are: the regenerator outlet temperature is 700°C, the regenerator pressure is 0.6MPa, and the regeneration medium of the regenerator pressure is air. The operating conditions and product distribution are listed in Table 4.

[0076] Comparative Example 3

[0077] The LCO was processed in the same manner as in Example 1, except that the catalyst used was not the aromatization catalyst in Example 1, but the DMMC-2 balance agent used in Comparative Example 1.

[0078] Comparative Example 4

[0079] LCO was processed in the same manner as in Example 1, except that the catalytic cracking reaction was not carried out in the presence of hydrogen, but nitrogen was used as the fluidizing gas.

[0080] Comparative Example 5

[0081] The LCO was processed in the same manner as in Example 1, except that the catalytic cracking reaction was carried out in the presence of hydrogen in the riser reactor.

[0082] Table 1

[0083] Raw oil name LCO <![CDATA[Density (20 °C), kg / m 3 > 911.2 Carbon content, weight % 88.93 Hydrogen content, weight % 10.08 Hydrocarbon mass composition Paraffins, weight % 11.3 Total cycloalkanes, weight % 30.1 Total aromatics, weight % 58.6 Gel, weight% 0 Total weight, weight % 100

[0084] Table 2

[0085] Catalyst No. DMMC-2 CAT-1 Micro-anti-activity 60 64 <![CDATA[Specific surface area, m 2 / g]]> 124 178 Pore ​​volume, ml / g 0.26 0.36 Sieve composition, weight % 0~40 microns 11.8 18.8 40~80 microns 53.2 58.6 >80 microns 35 22.6

[0086] Table 3

[0087]

[0088]

[0089]

[0090]

[0091] As shown in Table 3, compared with Comparative Example 5 (hydrogenation in a riser), Example 1 (circulating turbulent fluidized bed) has higher triene (ethylene + propylene + butene) and BTX yields, and the triene yields and BTX yields are increased by 2.96 and 5.45 percentage points, respectively. Compared with Comparative Example 3 (circulating turbulent fluidized bed hydrogenation using a non-aromatization catalyst) and Comparative Example 4 (circulating turbulent fluidized bed non-hydrogenation), Example 1 also has higher triene and BTX yields. The above results show that the circulating turbulent fluidized bed reactor with hydrogenation, high temperature, and large agent-to-oil ratio used in the present invention has higher light olefin and aromatic hydrocarbon yields under the action of a catalytic cracking catalyst with aromatization function.

[0092] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0093] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0094] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing light olefins and aromatics by processing LCO in a circulating turbulent fluidized bed, the method comprising: S1. In a hydrogen atmosphere, contacting an LCO feedstock with an aromatization catalytic cracking catalyst at the lower part of a circulating turbulent fluidized bed reactor and performing a catalytic cracking reaction in a co-current manner to obtain a reaction mixture; The conditions of the catalytic cracking reaction include: reaction temperature of 525-625°C, reaction pressure of 0.4-1.2MPa, hydrogen partial pressure of 0.2-1.0MPa, catalyst-oil weight ratio of 8-30, and residence time of LCO feedstock of 4-20 seconds; the reaction temperature refers to the outlet temperature of the circulating turbulent fluidized bed reactor; The particle concentration of the aromatization catalytic cracking catalyst in the circulating turbulent fluidized bed reactor is 20-35%, and the circulation rate is 100-800 kg / m 2 s, fluidizing gas velocity is 0.1-15m / s; S2. Separating the reaction mixture to obtain product oil and gas containing light olefins and aromatics and a catalyst to be produced.

2. The method according to claim 1, wherein: The method further comprises: selectively stripping and charring the spent catalyst, and returning at least a portion of the resulting regenerated catalyst to the circulating turbulent fluidized bed reactor of step S1 to be used as the aromatization catalytic cracking catalyst.

3. The method according to claim 2, wherein: The conditions for the char regeneration include: a temperature of 550-800° C., a pressure of 0.2-2.0 MPa, and a time of 2-15 minutes.

4. The method according to claim 1, wherein: The separation is carried out in a rapid separation device.

5. The method according to claim 1, wherein: The method further comprises: preheating the LCO raw material before introducing it into the circulating turbulent fluidized bed reactor, wherein the temperature of the preheated LCO raw material is 100-300°C.

6. The method according to claim 1, wherein: The hydrogen atmosphere contains hydrogen and / or dry gas.

7. The method according to claim 1, wherein: The aromatization catalytic cracking catalyst comprises, on a dry basis and based on the total weight of the aromatization catalytic cracking catalyst, 1-60 wt% of zeolite, 5-95 wt% of inorganic oxide, 0-80 wt% of clay and 0-20 wt% of active metal component; The zeolite contains 40-100 wt% of medium pore zeolite and 0-60 wt% of large pore zeolite on a dry basis and based on the total weight of the zeolite.

8. The method according to claim 7, wherein: The large-pore zeolite is selected from one or more of high-silicon Y, rare earth Y, rare earth hydrogen Y and ultra-stable Y, and the medium-pore zeolite is selected from ZSM series zeolite and / or ZRP zeolite; The inorganic oxide is selected from silicon dioxide and / or aluminum oxide; The clay is selected from one or more of kaolin, montmorillonite, diatomaceous earth, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite; The active metal component contains one or more selected from Fe, Co, Ni, Cu, Zn and rare earth metals.

Images