Reaction system and method for producing light olefins and aromatics by catalytic cracking

Abstract

The application relates to a method for producing low-carbon olefins and aromatic hydrocarbons by catalytic cracking, which comprises: performing non-hydrogen catalytic cracking of heavy raw oil in the presence of a first catalyst in a riser reactor; performing catalytic cracking of a second raw oil in the presence of a second catalyst in a dense-phase fluidized bed reactor; wherein, in the dense-phase fluidized bed reactor, the particle concentration is 15-50%, the gas velocity is 0.1-15 m / s, and the catalyst circulation rate is 200-1000 kg / m 2 s.The method fully utilizes the characteristics of the riser reactor and the dense-phase fluidized bed, and helps to improve the selectivity and yield of low-carbon olefins and aromatic hydrocarbons.

Description

Technical Field

[0001] The present invention belongs to the field of catalytic cracking of petroleum hydrocarbons, and in particular relates to a reaction system and method for maximizing the production of light olefins and aromatics. Background Art

[0002] Currently, crude oil quality is deteriorating, and the domestic diesel-to-gasoline ratio continues to decline. This will further exacerbate the problems of crude oil degradation and diesel surpluses in refineries. Light olefins and aromatics are important organic chemical raw materials, with strong domestic demand and a high degree of external dependence. Given the combination of overcapacity in domestic refining and a shortage of organic chemical raw materials, the shift from refining to chemical production is inevitable.

[0003] Currently, catalytic cracking processes for producing light olefins and aromatics primarily utilize riser reactors, with the most widely used being the DCC technology developed by the Sinopec Research Institute of Petrochemicals. The bed particle concentration in riser reactors is relatively low, typically below 10% (Bi H et al., Chemical Engineering Science, 2000, 55:4789-4825). High conversion rates cannot be achieved solely with riser reactors, so this technology utilizes a riser-plus-bed reactor configuration to enhance cracking depth. Patents CN101362963A, CN101747928A, and CN1667089A, among others, utilize DCC technology to disclose methods for producing both propylene and aromatics through catalytic cracking of heavy feedstocks. By recycling distillates such as difficult-to-crack feedstocks or recycled cracking feedstocks, propylene yields can be increased to over 40%. BTX can then be produced by extracting aromatics-rich fractions using aromatics extraction technology. All of the aforementioned patents utilize riser reactors. However, these reactors inherently suffer from low bed particle concentration, non-uniform radial annular core distribution, and significant axial backmixing, which can affect the conversion and selectivity of catalytic cracking reactions. Furthermore, while recycling can process a certain amount of recycled oil, the presence of recycled oil in the same reactor creates a vicious adsorption-reaction competition with heavy oil, impacting the selectivity and conversion of the reaction.

[0004] In addition, the above patents are all based on non-hydrogen catalytic cracking reaction atmospheres. Although they are suitable for the saturated cracking of catalytic cracking diesel LCO to produce light olefins, they are not suitable for aromatic dealkylation reactions. The activation energy barrier of LCO aromatic dealkylation reactions is high, requiring not only a high reaction temperature, but also a hydrogen atmosphere in the catalytic reaction environment. There are two main methods for producing BTX in the presence of hydrogen: hydrogen thermal cracking and hydrogen catalytic cracking. Both methods have the problem of high coke production, making it difficult for the reaction to operate stably for a long time, limiting their promotion and application.

[0005] The inventors of the present invention have found through extensive literature research and experimental studies that: (1) A single riser catalytic cracking unit can process both heavy oil and light oil, and usually adopts a riser + bed type, where the heavy oil is first fed into the lower end of the riser for reaction, and the light oil is then injected into the bed reactor for cracking reaction with the carbon-containing catalyst, resulting in a low conversion rate; (2) Conventional riser catalytic cracking processes all react in a non-hydrogen atmosphere, and although they are suitable for saturated cracking of LCO to produce light olefins, they are not suitable for aromatic dealkylation reactions, which affects the aromatic yield; (3) Conventional riser reactors have a low particle concentration (usually less than 10%) and uneven radial and axial distribution, which affects the selectivity of intermediates such as propylene.

[0006] The existing technology has a low yield of light olefins and aromatics. 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. Summary of the Invention

[0007] The present application provides a method for producing light olefins and aromatics by catalytic cracking, comprising:

[0008] In the riser reactor, the heavy crude oil is subjected to non-hydrocatalytic cracking in the presence of a first catalyst, the oil and gas after the reaction enter a first separation system for separation, the first spent catalyst after the reaction enters a first regenerator for regeneration, and the regenerated first catalyst is circulated back to the riser reactor;

[0009] In a dense phase fluidized bed reactor, a second feedstock is subjected to catalytic cracking in the presence of a second catalyst. The oil and gas after the reaction enter a second separation system for separation. The second regenerated catalyst after the reaction enters a second regenerator after depressurization through a lock hopper for regeneration. The regenerated second regenerated catalyst is pressurized through the lock hopper and then circulated back to the dense phase fluidized bed reactor.

[0010] In the dense phase fluidized bed reactor, the particle concentration is 15-50%; the gas velocity is 0.1-15m / s, and the catalyst circulation rate is 200-1000kg / m 2 s.

[0011] In one embodiment, the first regenerator and the second regenerator are the same regenerator.

[0012] In one embodiment, the first catalyst and the second catalyst are the same catalyst.

[0013] In one embodiment, in the riser reactor, the reaction temperature is 500-700° C., the reaction pressure is 0.1-2.0 MPa, the catalyst-oil ratio is 5-100, and the residence time is 0.1-20 seconds.

[0014] In one embodiment, the second feedstock is catalytically cracked in the presence of a second catalyst under hydrogen conditions in a dense phase fluidized bed reactor.

[0015] In one embodiment, in a dense phase fluidized bed reactor, the reaction temperature is 500-700° C., the reaction pressure is 0.1-2.0 MPa, the catalyst-oil ratio is 5-100, the hydrogen-oil volume ratio is 100-1500, and the residence time is 0.1-20 seconds.

[0016] In one embodiment, the dense phase fluidized bed reactor has a structure with a thin top and a thick bottom, the diameter ratio of the lower thick diameter fluidized bed to the upper thin diameter conveying bed is 2-10:1, and the height ratio of the lower thick diameter fluidized bed to the upper thin diameter conveying bed is 1-15:1.

[0017] In one embodiment, the first catalyst and the second catalyst are catalytic cracking catalysts having aromatization function.

[0018] In one embodiment, the catalyst comprises a large-pore zeolite and an oxide, and optionally a medium-pore zeolite and optionally a clay, preferably comprising a medium-pore zeolite and a large-pore zeolite modified by metal elements and / or non-metallic elements as active components, wherein the metal elements used for modification are selected from Fe, Co, Ni, Cu, Zn and rare earth metals, and the non-metallic elements are selected from P.

[0019] In one embodiment, the second feedstock oil is selected from heavy feedstock oil and light feedstock oil.

[0020] In one embodiment, the heavy feedstock oil is various heavy petroleum hydrocarbons with a carbon number greater than 20, including wax oil and residual oil; the light feedstock oil includes straight-run diesel, hydrogenated straight-run diesel, light cycle oil (LCO) and hydrogenated light cycle oil (HLCO).

[0021] The present application also provides a reaction system for producing light olefins and aromatics by catalytic cracking, comprising:

[0022] Riser reactor system, comprising:

[0023] Riser reactor,

[0024] Riser top cyclone separator, and

[0025] Riser stripper,

[0026] wherein the riser top cyclone separator is disposed at the top of the riser reactor and is in communication with the riser stripper, so that the first spent catalyst separated by the riser top cyclone separator is stripped in the riser stripper;

[0027] Dense phase fluidized bed reactor system, comprising:

[0028] Dense phase fluidized bed reactor,

[0029] dense phase fluidized bed cyclone separators, and

[0030] Dense phase fluidized bed stripper,

[0031] The dense phase fluidized bed cyclone separator is disposed on the top of the dense phase fluidized bed reactor and is in communication with the dense phase fluidized bed stripper, so that the second spent catalyst separated by the dense phase fluidized bed cyclone separator is stripped in the dense phase fluidized bed stripper;

[0032] a lock hopper, wherein the dense phase fluidized bed stripper is in communication with the lock hopper, so that the second spent catalyst stripped by the dense phase fluidized bed stripper enters the lock hopper for depressurization; the lock hopper is also in communication with the dense phase fluidized bed reactor, so that the regenerated catalyst pressurized by the lock hopper is circulated back to the dense phase fluidized bed reactor;

[0033] Regenerator,

[0034] The riser stripper is connected to the regenerator, so that the first catalyst to be regenerated after being stripped by the riser stripper enters the regenerator for regeneration; the regenerator is also connected to the riser reactor, so that the regenerated catalyst regenerated by the regenerator is circulated back to the riser reactor;

[0035] The regenerator is also connected to the lock hopper, so that the second catalyst to be regenerated that has been depressurized through the lock hopper enters the regenerator for regeneration, and the regenerated catalyst that has been regenerated through the regenerator is circulated back to the lock hopper.

[0036] In one embodiment, the dense phase fluidized bed reactor has a structure with a thin top and a thick bottom, the diameter ratio of the lower thick diameter fluidized bed to the upper thin diameter conveying bed is 2-10:1, and the height ratio of the lower thick diameter fluidized bed to the upper thin diameter conveying bed is 1-15:1.

[0037] The method of the present invention fully utilizes the characteristics of the riser reactor and the dense phase fluidized bed, and is helpful to improve the selectivity and yield of light olefins and aromatics. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the process flow of an embodiment of the present invention.

[0039] Figure 1In the figure, 1 is the fluidizing medium; 2 is the riser inlet distribution plate; 3 is the riser oil inlet nozzle; 4 is the riser reactor; 5 is the riser top cyclone separator; 6 is the riser stripper; 7 is the riser stripping steam; 8 is the riser product oil and gas discharge pipeline; 9 is the regenerator; 10 is the regenerator cyclone separator; 11 is the flue gas outlet pipeline; 12 is the regeneration medium; 13 is the lock hopper; 14 is the hydrogen-containing fluidizing medium; 15 is the dense phase fluidized bed inlet distribution plate; 16 is the dense phase fluidized bed oil inlet nozzle; 17 is the dense phase fluidized bed; 18 is the conveying bed; 19 is the lifting steam; 20 is the dense phase fluidized bed cyclone separator; 21 is the dense phase fluidized bed stripper; 22 is the dense phase fluidized bed stripping steam; 23 is the dense phase fluidized bed product oil and gas discharge pipeline. DETAILED DESCRIPTION

[0040] The present application will be further described in detail below through the accompanying drawings and examples, through which the features and advantages of the present application will become more clear and distinct.

[0041] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0042] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0043] The present application provides a reaction system and method for producing light olefins and aromatics by catalytic cracking. Figure 1 The reaction system and method are described.

[0044] The present application provides a method for producing light olefins and aromatics by catalytic cracking, comprising:

[0045] In the riser reactor, the heavy crude oil is subjected to non-hydrocatalytic cracking in the presence of a first catalyst, the oil and gas after the reaction enter a first separation system for separation, the first spent catalyst after the reaction enters a first regenerator for regeneration, and the regenerated first catalyst is circulated back to the riser reactor;

[0046] In a dense phase fluidized bed reactor, a second feedstock is subjected to catalytic cracking in the presence of a second catalyst. The oil and gas after the reaction enter a second separation system for separation. The second regenerated catalyst after the reaction enters a second regenerator after depressurization through a lock hopper for regeneration. The regenerated second regenerated catalyst is pressurized through the lock hopper and then circulated back to the dense phase fluidized bed reactor.

[0047] In the dense phase fluidized bed reactor, the particle concentration is 15-50%; the gas velocity is 0.1-15m / s, and the catalyst circulation rate is 200-1000kg / m 2 s.

[0048] In one embodiment, the first regenerator and the second regenerator may be the same regenerator, or may be different regenerators. However, to save investment and facilitate operation, preferably, the first regenerator and the second regenerator are the same regenerator, so that the catalyst to be regenerated from the riser reactor and the dense phase fluidized bed reactor is regenerated in the same regenerator.

[0049] The first catalyst and the second catalyst used in the riser reactor and the dense phase fluidized bed reactor can be the same or different. In one embodiment, the first catalyst and the second catalyst are the same catalyst, so that the first catalyst and the second catalyst can be regenerated in the same regenerator and recycled.

[0050] In one embodiment, both the first catalyst and the second catalyst are catalytic cracking catalysts having aromatization functionality. In one embodiment, the catalyst comprises a large-pore zeolite and an oxide, and optionally a medium-pore zeolite and optionally a clay. Preferably, the catalyst may comprise a medium-pore zeolite and a large-pore zeolite modified with metal elements and / or non-metallic elements as active components, wherein the metal elements used for modification are selected from Fe, Co, Ni, Cu, Zn, and rare earth metals, and the non-metallic elements are selected from P.

[0051] In one embodiment, the catalyst is a catalytic cracking agent composed of large-pore zeolite, oxide, optional medium-pore zeolite, and optional clay, preferably a catalytic cracking catalyst with aromatization function, in which medium-pore zeolite and large-pore zeolite modified with metals such as Fe, Co, Ni, Cu, Zn and rare earths and / or non-metals such as P are used as active components.

[0052] The catalyst is primarily composed of zeolite, inorganic oxide, and optional clay, with zeolite accounting for 1-60 weight percent, oxide 5-95 weight percent, clay 0-80 weight percent, and a modifying metal component. The zeolite can be either large-pore zeolite or medium-pore zeolite, with the large-pore zeolite accounting for 40-100 weight percent, preferably 50-95 weight percent, of the total zeolite weight; the medium-pore zeolite accounting for 0-45 weight percent, preferably 15-45 weight percent. The large-pore zeolite can be selected from the Y series zeolites, including rare earth Y (REY), rare earth hydrogen Y (REHY), ultrastable Y obtained by different methods, and high-silicon Y. The medium-pore zeolite is selected from ZSM series zeolites and / or ZRP zeolites. These medium-pore zeolites may also be modified with non-metallic elements such as phosphorus. The ZSM series zeolite may be selected from one or a mixture of two or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, and other zeolites with similar structures. Zeolites also include BETA molecular sieves, which have both macroporous and mesoporous structures.

[0053] The oxide as a binder can be selected from silicon dioxide (SiO2) and / or aluminum oxide (Al2O3). On a dry weight basis, silicon dioxide can account for 45-95 weight percent of the inorganic oxide, and aluminum oxide can account for 15-55 weight percent.

[0054] The clay as a matrix (ie, carrier) can be selected from one or more of silicon dioxide, kaolin and / or halloysite, montmorillonite, diatomaceous earth, halloysite, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

[0055] The modified metal component is a metal having a dehydrogenating effect, primarily a metal element from the fourth or fifth period of the transition metals, preferably an oxide or hydroxide of any one, two, three, or more transition metals such as Fe, Co, Ni, Cu, Zn, and rare earth metals. The modified metal component, calculated as metal oxide, accounts for 0-20% by weight, preferably 1.0-15% by weight, of the total weight of the catalyst.

[0056] Preferably, the catalyst is a catalytic cracking catalyst having aromatization function, which uses metals such as Cu and P, non-metal-modified medium-pore zeolite and large-pore zeolite as active components.

[0057] The regeneration conditions of the catalyst in the regenerator are as follows: the regeneration temperature can be 550-800°C, and the regeneration medium can be air.

[0058] In the present application, the reaction in the riser reactor is a non-hydrogenation reaction, and various riser reactors commonly used in the art can be used. In one embodiment, in the riser reactor, the reaction temperature is 500-700 ° C, the reaction pressure is 0.1-2.0 MPa, the catalyst-oil ratio (i.e., the weight ratio of catalyst to feedstock oil, the same below) is 5-100, and the residence time is 0.1-20 seconds. The heavy feedstock oil used for the riser reactor can be various heavy petroleum hydrocarbons with a carbon number greater than 20, including wax oil and residual oil. The heavy feedstock oil is preheated and enters the riser reactor, and the preheating temperature can be 100-300 ° C.

[0059] In one embodiment, in a dense fluidized bed reactor, the second feedstock oil can be subjected to catalytic cracking in the presence of a second catalyst under non-hydrogen conditions. Preferably, in a dense fluidized bed reactor, the second feedstock oil can also be subjected to catalytic cracking in the presence of a second catalyst under hydrogen conditions, thereby increasing the yield of light olefins and aromatics. In the dense fluidized bed, the catalyst is uniformly fluidized in a hydrogen-containing fluidized medium and then enters the reactor through a distribution plate. After preheating, the feedstock oil enters the bottom of the reactor through a nozzle and is mixed and contacted with the catalyst. The reaction oil gas and the catalyst flow upwardly into the dense fluidized bed for catalytic cracking reaction. A small diameter conveying bed is connected in series at the top outlet of the dense fluidized bed, and steam is added to increase the gas-solid conveying speed. In one embodiment, the hydrogen-containing fluidized medium of the present invention can be a hydrogen-containing fluidized medium such as hydrogen and dry gas.

[0060] In the present application, the particle concentration of the dense phase fluidized bed reactor is between 15-50%. In order to ensure that the bed is in a circulating dense phase fluidization, the operation range should be as follows: the gas velocity is between bubbling fluidization and rapid fluidization. Since the characteristic fluidization gas velocity corresponding to different particles is different, the preferred gas velocity is in the range of 0.1-15m / s. The inventors of the present application have found that a suitable catalyst circulation rate is more conducive to the production of aromatics. Too low a circulation rate will result in insufficient reaction intensity and a low aromatics yield. Too high a circulation amount will increase by-products such as coke. At the same time, it was found that the production of aromatics requires a longer contact time. In one embodiment, the present application can achieve a suitable catalyst circulation rate of 200-1000kg / m 2 s, for example 500kg / m 2 s and above, 550kg / m 2 s and above, 600kg / m 2 s or above, or 1000kg / m 2 s or less, 900kg / m 2 s or less, or 800kg / m 2 s or less.

[0061] In one embodiment, the dense phase fluidized bed reactor has a structure with a thin top and a thick bottom. The lower thick diameter fluidized bed and the upper thin diameter conveying bed are connected in series to form a dense phase fluidized bed reactor. The diameter ratio of the lower thick diameter fluidized bed and the upper thin diameter conveying bed is 2-10:1 (for example, 2-8:1, 2-6:1, 2-5:1, 2-4:1, etc.), and the height ratio of the lower thick diameter fluidized bed to the upper thin diameter conveying bed is 1-15:1 (for example, 1-10:1, 1-8:1, 2-6:1, 2-4:1, etc.). With such a dense phase fluidized bed reactor, the lower thick diameter fluidized bed can ensure that the bed is in a dense phase operating state, which can enhance gas-solid contact and avoid backmixing. At the same time, the upper thin diameter is combined with supplementary steam to ensure that the top cyclone separator has a high separation efficiency under high particle circulation velocity.

[0062] In one embodiment, in a dense phase fluidized bed reactor, the reaction temperature is 500-700° C., the reaction pressure is 0.1-2.0 MPa, the catalyst-oil ratio is 5-100, the hydrogen-oil volume ratio is 100-1500, and the residence time is 0.1-20 seconds.

[0063] In one embodiment, the second feedstock oil used in the dense-phase fluidized bed reactor may include heavy feedstock oil and light feedstock oil. The heavy feedstock oil may be various heavy petroleum hydrocarbons with a carbon number greater than 20, including wax oil and residual oil; the light feedstock oil may include straight-run diesel, hydrogenated straight-run diesel, light cycle oil (LCO), and hydrogenated light cycle oil (HLCO). The second feedstock oil is preheated before entering the dense-phase fluidized bed reactor. The preheating temperature may be 100-300°C.

[0064] In a preferred embodiment, the present invention can combine a non-hydrogenation riser reactor and a dense-phase fluidized bed reactor (preferably operated under hydrogenation conditions) to provide a method for processing heavy oil and light oils such as LCO to maximize the production of light olefins and aromatics. Preferably, heavy petroleum hydrocarbons such as residue are subjected to non-hydrogenation catalytic cracking in the riser catalytic cracking unit, while light hydrocarbons such as diesel are subjected to hydrocatalytic cracking in the dense-phase fluidized bed unit. Through suitable dense-phase operating conditions and a long residence time, the production of light olefins and aromatics from heavy petroleum hydrocarbons and light hydrocarbons is maximized.

[0065] thus, Figure 1 A reaction system for producing light olefins and aromatics by catalytic cracking is shown, comprising:

[0066] Riser reactor system, comprising:

[0067] Riser reactor 4,

[0068] Riser top cyclone separator 5, and

[0069] Riser stripper 6,

[0070] The riser top cyclone separator 5 is disposed on the top of the riser reactor 4 and is connected to the riser stripper 6, so that the first spent catalyst separated by the riser top cyclone separator 5 is stripped in the riser stripper 6;

[0071] Dense phase fluidized bed reactor system, comprising:

[0072] Dense phase fluidized bed reactor 17,

[0073] Dense phase fluidized bed cyclone separator 20, and

[0074] Dense phase fluidized bed stripper 21,

[0075] The dense phase fluidized bed cyclone separator 20 is disposed on the top of the dense phase fluidized bed reactor 17 and is in communication with the dense phase fluidized bed stripper 21, so that the second spent catalyst separated by the dense phase fluidized bed cyclone separator 20 is stripped in the dense phase fluidized bed stripper 21;

[0076] The lock hopper 13 is connected to the dense phase fluidized bed stripper 21, so that the second spent catalyst stripped by the dense phase fluidized bed stripper 21 enters the lock hopper 13 for depressurization. The lock hopper 13 is also connected to the dense phase fluidized bed reactor 17, so that the regenerated catalyst pressurized by the lock hopper 13 is circulated back to the dense phase fluidized bed reactor 21.

[0077] Regenerator 9,

[0078] The riser stripper 6 is connected to the regenerator 9, so that the first regenerated catalyst stripped by the riser stripper 6 enters the regenerator 9 for regeneration; the regenerator 9 is also connected to the riser reactor 4, so that the regenerated catalyst regenerated by the regenerator 6 is circulated back to the riser reactor 4;

[0079] The regenerator 9 is also connected to the lock hopper 13 so that the second regenerated catalyst dehydrogenated and depressurized through the lock hopper 13 enters the regenerator 9 for regeneration, and the regenerated catalyst regenerated through the regenerator 9 is circulated back to the lock hopper 13.

[0080] like Figure 1As shown, a portion of the catalytic cracking catalyst from the regenerator 9 enters the riser reactor 4, while the remaining portion is deoxygenated and pressurized in a lock hopper 13 before entering a dense-phase fluidized bed reactor 17. Within the riser reactor 4, the catalyst is uniformly fluidized in a non-hydrogen-containing fluidizing medium 1 and then enters the reactor 4 through a distribution plate 2. After preheating, the feedstock oil enters the bottom of the reactor through a nozzle 3, where it mixes with the catalyst. The reaction oil vapor and catalyst flow concurrently upward into the riser reactor 4 for catalytic cracking. The reaction product oil vapor and catalyst are separated at the top of the riser reactor by a cyclone separator 5. The separated product oil vapor enters a fractionation unit (not shown) via a riser product oil vapor discharge line 8. The catalyst separated by the cyclone separator 5 enters a stripper 6 where it is stripped with riser stripping steam 7. After stripping, the reacted catalyst enters the regenerator 9, where it is charred by a regeneration medium 12. The resulting flue gas is separated by a cyclone separator 10 and discharged through a flue gas outlet line 11. The regenerated catalyst enters the bottom of the riser reactor for the next cycle.

[0081] Within dense fluidized bed reactor 17, the catalyst is uniformly fluidized in hydrogen-containing fluidizing medium 14 before entering the reactor through distribution plate 15. After preheating, the feedstock enters the reactor's bottom through nozzle 16, where it mixes with the catalyst. The reaction oil and catalyst flow co-currently upward into dense fluidized bed reactor 17 for catalytic cracking. A small-diameter transport bed 18 is connected in series at the top outlet of the dense fluidized bed, and supplemental steam 19 is used to increase the gas-solid transport rate. The reaction product oil and catalyst are separated at the top of the dense fluidized bed by cyclone separator 20. The separated product oil and gas enter a fractionation unit (not shown) via discharge line 23. The catalyst separated by cyclone separator 20 enters stripper 21 for stripping. The reacted catalyst is stripped by the dense phase fluidized bed stripping steam 22, and then dehydrogenated and depressurized through the lock hopper 13 before entering the regenerator for charring. The flue gas generated by the charring is separated by the cyclone separator 20 and discharged. The regenerated catalyst enters the lock hopper 13 for deoxygenation and pressurization and is then transported back to the dense phase fluidized bed reactor 17 for the next cycle.

[0082] For the dense phase fluidized bed reactor 17 under non-hydrogen conditions, the corresponding process can be carried out by replacing the hydrogen-containing fluidizing medium 14 with a corresponding non-hydrogen-containing fluidizing medium.

[0083] Compared with the prior art, the present invention has the following technical effects:

[0084] (1) It has strong adaptability to raw materials. It can not only process low-quality heavy raw materials with high density and low hydrogen content and carry out deep catalytic cracking process, but also process light diesel raw materials such as straight-run diesel, hydrogenated straight diesel, LCO, and HLCO.

[0085] (2) The combination of the riser reactor and the dense phase fluidized bed reactor in the present application has higher bed particle concentration and uniform axial and radial distribution, thus helping to increase the yield of aromatic hydrocarbons and thus the selectivity of the product.

[0086] (3) The operation in the hydrogen atmosphere helps to increase the yield of aromatic hydrocarbons by the dealkylation of the hydrogenated LCO aromatic hydrocarbons, and the hydrogen atmosphere can reduce the hydrocarbon partial pressure, thus increasing the yield of low carbon olefins.

[0087] (4) The use of the catalytic cracking catalyst with aromatization function in the hydrogen atmosphere helps to increase the yield of aromatic hydrocarbons.

[0088] The present application is further illustrated in combination with specific examples.

[0089] The properties of the raw materials used in the examples are shown in Table 1.

[0090] The catalysts used in the examples are the same, and the preparation method is briefly described as follows:

[0091] 1) 20 kg of ammonium chloride was dissolved in 1000 kg of water, 100 kg (dry basis) of crystallized product DASY zeolite (produced by the Catalyst Factory of Qilu Petrochemical Company, 2.445-2.448 nm, rare earth content RE2O3 = 2.0 wt%) was added to the solution, and after 0.6 h of exchange at 90°C, the filter cake was obtained by filtration; 40 kg of Cu(NO3)2·6H2O dissolved in 200 kg of water was added and mixed with the filter cake for impregnation and drying; then calcination treatment was carried out at 560°C for 2 hours to obtain copper-containing large-pore zeolite with an elemental analysis chemical composition of 0.1Na2O·5.1Al2O3·18.2CuO·3.8RE2O3·88.1SiO2.

[0092] 2) 20 kg of ammonium phosphate was dissolved in 600 kg of water, and stirred uniformly, 50 kg of MFI structure mesoporous ZRP-1 zeolite (industrial product of the Catalyst Factory of Qilu Petrochemical Company, SiO2 / Al2O3 = 30) was added to the solution, and impregnated and stirred at 60°C for 3 h, and the filter cake was obtained by filtration; the molecular sieve filter cake was dried at 120°C, and then calcination treatment was carried out at 550°C for 1 hour to obtain phosphorus-containing mesoporous zeolite.

[0093] 3) Use 250kg of decationized water to slurry 80kg of halloysite (industrial product of Suzhou Porcelain Clay Company, solid content 71.6m%), then add 50kg of pseudo-boehmite (industrial product of Shandong Aluminum Plant, solid content 63m%), adjust the pH to 2-4 with hydrochloric acid, stir evenly, and let stand for aging at 60-70°C for 1 hour, maintaining the pH at 2-4, reduce the temperature to below 60°C, add 40kg of aluminum sol (product of Qilu Petrochemical Company Catalyst Plant, Al2O3 content of 21.7m%), and stir for 40 minutes to obtain a mixed slurry.

[0094] 4) The copper-containing large-pore zeolite prepared in step 1) and the phosphorus-containing MFI-structured mesoporous ZRP-1 zeolite prepared in step 2 (15.0 kg dry basis) were added to the mixed slurry obtained in step 3) and stirred uniformly. 5 g of commercial alumina binder was then added. The mixture was placed in a bonding machine, and an appropriate amount of water was added. The mixture was thoroughly stirred and allowed to stand in air for 5 hours. The mixture was spray-dried to form a slurry. The mixture was dried in a drying oven at 120°C for 3 hours, washed with ammonium dihydrogen phosphate solution (phosphorus content 1% by mass) to remove free Na+, and dried again to obtain a catalyst designated CAT-1. The properties of this catalyst are listed in Table 2.

[0095] Example 1

[0096] This embodiment follows Figure 1 The device and process were tested. Reactions were conducted in a small-scale fluidized bed reactor, with a riser reactor serving as the first reactor and a dense-phase fluidized bed serving as the second reactor. Both reactors used the heavy oil listed in Table 1 as the feedstock, operated in a non-hydrogenation mode, and employed a CAT-1 catalyst with an activity of 64. Catalyst properties are listed in Table 2, and reaction and regeneration process conditions are listed in Table 3. The dense-phase fluidized bed reactor has a top-thin, bottom-coarse structure. A lower coarse-diameter fluidized bed and an upper fine-diameter conveying bed are connected in series to form the dense-phase fluidized bed reactor. The diameter ratio of the lower coarse-diameter fluidized bed and the upper fine-diameter conveying bed is 2:1, and the height ratio of the lower coarse-diameter fluidized bed to the upper fine-diameter conveying bed is 4:1.

[0097] A portion of the aromatization catalytic cracking catalyst from regenerator 9 enters riser reactor 4, while the remaining portion is deoxygenated and pressurized through lock hopper 13 before entering dense-phase fluidized bed 17. Within riser reactor 4, the catalyst is uniformly fluidized in non-hydrogen-containing fluidizing medium 1 and then enters the reactor through distribution plate 2. After being preheated, heavy oil enters the bottom of the reactor through nozzle 3, where it mixes with the catalyst. The reactant oil and catalyst then flow upward concurrently into riser reactor 4 to undergo a catalytic cracking reaction.

[0098] The reaction product gas and catalyst are separated at the top of the riser reactor by a cyclone separator 5. The separated product gas enters the fractionation unit, and the catalyst separated by the cyclone separator enters the stripper for stripping. After stripping, the reacted catalyst enters the regenerator through a regeneration slide valve for charring. The resulting charring flue gas is separated by a cyclone separator and discharged. The regenerated catalyst enters the bottom of the riser reactor through a regeneration slide valve for the next cycle. Within the dense fluidized bed, the catalyst is uniformly fluidized in a non-hydrogen-containing fluidizing medium before entering the reactor through a distribution plate. After preheating, heavy oil enters the bottom of the reactor through a nozzle to mix and contact the catalyst. The reacted gas and catalyst flow concurrently upward into the dense fluidized bed for catalytic cracking. A small-diameter transport bed is connected in series at the top outlet of the dense fluidized bed, and steam is added to increase the gas-solid transport rate. The reacted gas and catalyst are separated at the top of the dense fluidized bed by a cyclone separator. The separated product gas and catalyst enter the fractionation unit, and the catalyst separated by the cyclone separator enters the stripper for stripping. After the catalyst is stripped, it is depressurized through a lock hopper and then enters the regenerator for charring. The resulting flue gas is separated by a cyclone separator and discharged. The regenerated catalyst enters the lock hopper through a waiting slide valve for the next cycle. The product distribution is listed in Table 3.

[0099] As can be seen from Table 3, in Example 1, the cracked gas yield was 23.6% by weight, the gasoline yield was 43.4% by weight, the diesel yield was 20.9% by weight, the slurry oil yield was 4.7% by weight, the coke yield was 7.35% by weight, the triene yield was 14.7% by weight, and the BTX yield was 14.2% by weight.

[0100] Comparative Example 1

[0101] This comparative example uses an existing small riser reactor to carry out the reaction. The catalyst and feed oil are the same as those in Example 1. A double riser reactor operation mode is adopted. The operating conditions and product distribution are listed in Table 3.

[0102] As can be seen from Table 3, Example 1 has higher triene yields and BTX yields, but lower coke yields than Comparative Example 1. The triene yields and BTX yields increased by 1.2 and 1.6 percentage points, respectively, while the coke yield decreased by 2.8 percentage points.

[0103] Example 2

[0104] This embodiment follows Figure 1The device and process were tested. The reaction was carried out in a small-scale fluidized bed reactor, with the riser reactor as the first reactor and the dense-phase fluidized bed as the second reactor. The riser reactor used the heavy oil listed in Table 1 as the feedstock and operated in a non-hydrogenation mode. The dense-phase fluidized bed used the LCO listed in Table 1 as the feedstock and operated in a non-hydrogenation mode. Both reactors used CAT-1 catalyst with an activity of 64. The catalyst properties are listed in Table 2, and the reaction and regeneration process conditions are listed in Table 3. The dense-phase fluidized bed reactor has a top-thin, bottom-thick structure. The lower coarse-diameter fluidized bed and the upper fine-diameter conveying bed are connected in series to form the dense-phase fluidized bed reactor. The diameter ratio of the lower coarse-diameter fluidized bed and the upper fine-diameter conveying bed is 2:1, and the height ratio of the lower coarse-diameter fluidized bed to the upper fine-diameter conveying bed is 4:1.

[0105] A portion of the aromatization catalytic cracking catalyst from the regenerator enters the riser reactor, while the remaining portion is deoxygenated and pressurized in a lock hopper before entering the dense-phase fluidized bed. Within the riser reactor, the catalyst is uniformly fluidized in a non-hydrogenated fluidizing medium and then enters the reactor through a distribution plate. After preheating, the heavy oil enters the reactor bottom through a nozzle to mix and contact the catalyst. The reaction oil vapor and catalyst flow simultaneously upward into the riser reactor for catalytic cracking. The reaction product oil vapor and catalyst are separated by a cyclone separator at the top of the riser reactor. The separated product oil vapor enters the fractionation unit, and the catalyst separated by the cyclone separator enters the stripper for stripping. After stripping, the reacted catalyst enters the regenerator through a regeneration slide valve for charring. The resulting flue gas is separated by a cyclone separator and discharged. The regenerated catalyst enters the bottom of the riser reactor through a regeneration slide valve for the next cycle. In a dense fluidized bed, the catalyst is uniformly fluidized in the fluidizing medium before entering the reactor through a distribution plate. After preheating, LCO enters the reactor through a nozzle at the bottom of the reactor to mix and contact with the catalyst. The reaction gas and catalyst flow simultaneously upward into the dense fluidized bed for catalytic cracking. A small-diameter transport bed is connected in series at the top outlet of the dense fluidized bed, and supplemental steam is added to increase the gas-solid transport rate. The reaction products, gas and catalyst, are separated by a cyclone separator at the top of the dense fluidized bed. The separated gas enters the fractionation unit, and the catalyst separated by the cyclone enters the stripper for stripping. After stripping, the reacted catalyst is dehydrogenated and depressurized in a lock hopper before entering the regenerator for charring. The resulting flue gas is separated by a cyclone separator and discharged. The regenerated catalyst enters the lock hopper through a regeneration slide valve for the next cycle. The product distribution is listed in Table 4.

[0106] As can be seen from Table 4, in Example 2, the cracked gas yield was 26.5 wt%, the gasoline yield was 54.2 wt%, the diesel yield was 3.9 wt%, the slurry oil yield was 4.8 wt%, the coke yield was 10.6 wt%, the triene yield was 14.9 wt%, and the BTX yield was 16.4 wt%.

[0107] Example 3

[0108] This embodiment follows Figure 1 The device and process were tested. The reaction was carried out in a small fluidized bed reactor, with a riser reactor as the first reactor and a dense-phase fluidized bed as the second reactor. The riser reactor used the heavy oil listed in Table 1 as the feedstock and operated in a non-hydrogenation mode. The dense-phase fluidized bed used the LCO listed in Table 1 as the feedstock and operated in the presence of hydrogen. Both reactors used CAT-1 catalyst with an activity of 64. The catalyst properties are listed in Table 2, and the reaction and regeneration process conditions are listed in Table 3. The dense-phase fluidized bed reactor has a top-thin, bottom-thick structure. The lower, thick-diameter fluidized bed and the upper, thin-diameter conveying bed are connected in series to form the dense-phase fluidized bed reactor. The diameter ratio of the lower, thick-diameter fluidized bed and the upper, thin-diameter conveying bed is 2:1, and the height ratio of the lower, thick-diameter fluidized bed to the upper, thin-diameter conveying bed is 4:1.

[0109] A portion of the aromatization catalytic cracking catalyst from the regenerator enters the riser reactor, while the remaining portion is deoxygenated and pressurized in a lock hopper before entering the dense-phase fluidized bed. Within the riser reactor, the catalyst is uniformly fluidized in a non-hydrogenated fluidizing medium and then enters the reactor through a distribution plate. After preheating, the heavy oil enters the reactor bottom through a nozzle to mix and contact the catalyst. The reaction oil vapor and catalyst flow simultaneously upward into the riser reactor for catalytic cracking. The reaction product oil vapor and catalyst are separated by a cyclone separator at the top of the riser reactor. The separated product oil vapor enters the fractionation unit, and the catalyst separated by the cyclone separator enters the stripper for stripping. After stripping, the reacted catalyst enters the regenerator through a regeneration slide valve for charring. The resulting flue gas is separated by a cyclone separator and discharged. The regenerated catalyst enters the bottom of the riser reactor through a regeneration slide valve for the next cycle. In a dense fluidized bed, the catalyst is uniformly fluidized in a hydrogen-containing fluidizing medium before entering the reactor through a distribution plate. After preheating, LCO enters the reactor through a nozzle at the bottom of the reactor to mix and contact the catalyst. The reaction gas and catalyst flow concurrently upward into the dense fluidized bed for catalytic cracking. A small-diameter transport bed is connected in series at the top outlet of the dense fluidized bed, and supplemental steam is added to increase the gas-solid transport rate. The reaction products, gas and catalyst, are separated by a cyclone separator at the top of the dense fluidized bed. The separated gas and product enter the fractionation unit, and the catalyst separated by the cyclone separator enters the stripper for stripping. After stripping, the reacted catalyst is dehydrogenated and depressurized in a lock hopper before entering the regenerator for charring. The resulting flue gas is separated by a cyclone separator and discharged. The regenerated catalyst enters the lock hopper through a regeneration slide valve for the next cycle. The product distribution is listed in Table 4.

[0110] As shown in Table 4, in Example 3, the cracked gas yield was 29.1% by weight, the gasoline yield was 55.6% by weight, the diesel yield was 2.9% by weight, the slurry oil yield was 3.9% by weight, the coke yield was 8.5% by weight, the triene yield was 16.8% by weight, and the BTX yield was 18.7% by weight. Compared to Example 2, LCO produced in a dense fluidized bed in the presence of hydrogen exhibits higher triene and BTX yields.

[0111] Comparative Example 2

[0112] This comparative example uses an existing small-scale riser reactor for the reaction. The catalyst and feedstock oil are the same as those in Example 2. A double riser reactor is operated in a non-hydrogenation mode. The catalyst and process conditions of this comparative example are the same as those in Example 2. The operating conditions and product distribution are listed in Table 4.

[0113] As can be seen from Table 4, Example 3 has higher triene yields and BTX yields, but lower coke yields than Comparative Example 2. The triene yields and BTX yields increased by 2.7 and 3.5 percentage points, respectively, while the coke yield decreased by 2.6 percentage points.

[0114] The present application has been described above in conjunction with preferred embodiments, but these embodiments are merely exemplary and serve only as an illustrative example. On this basis, various replacements and improvements can be made to the present application, all of which fall within the scope of protection of the present application.

[0115] Table 1

[0116]

[0117] Table 2

[0118] Catalyst No. CAT-1 Micro-anti-activity 64 <![CDATA[比表面积,米 2 / g]]> 178 Pore ​​volume, ml / g 0.36 Sieve composition, weight % 0~40 microns 18.8 40-80 microns 58.6 >80 microns 22.6

[0119] Table 3

[0120] Example 1 Comparative Example 1 Catalyst name CAT-1 CAT-1 Catalyst activity (MAT) 64 64 Reaction operating conditions First reactor Reactor type Riser Riser crude oil heavy oil heavy oil Reaction pressure, MPa 0.4 0.4 Reactor inlet temperature, °C 660 660 Reactor outlet temperature, °C 508 505 Catalyst / feedstock oil weight ratio 7 7 Oil and gas residence time, s 2.5 2.5 Weight ratio of atomizing steam / total raw materials 0.10 0.10 Second reactor Reactor type dense phase fluidized bed Riser crude oil heavy oil heavy oil Reaction pressure, MPa 3.0 0.4 Hydrogen partial pressure, MPa ～ ～ Reactor inlet temperature, °C 660 660 Reactor outlet temperature, °C 515 520 Catalyst / feedstock oil weight ratio 30 7 Oil and gas residence time, s 6.0 1.5 <![CDATA[H2 / 循环油的体积比]]> ～ ～ Weight ratio of atomizing steam / total raw materials 0.1 0.1 Particle concentration, % 30 ～ Air velocity, m / s 1 ～ <![CDATA[颗粒循环速率,kg / m 2 s]]> 200 ～ Product yield, weight % cracked gas 23.6 21.4 gasoline 43.4 41.7 diesel fuel 20.9 21.8 Oil slurry 4.7 4.9 coke 7.35 10.2 total 100.0 100.0 Ethylene + propylene + butene 14.72 13.5 BTX 14.2 12.6

[0121] Table 4

[0122] Example 2 Example 3 Comparative Example 2 Catalyst name CAT-1 CAT-1 CAT-1 Catalyst activity (MAT) 64 64 64 Reaction operating conditions First reactor Reactor type Riser Riser Riser crude oil heavy oil heavy oil heavy oil Reactor outlet temperature, °C 511 511 511 Catalyst / feedstock oil weight ratio 9.5 9.5 9.5 Oil and gas residence time, s 4.5 4.5 4.5 Weight ratio of atomizing steam / total raw materials 0.15 0.15 0.15 Second reactor Reactor type dense phase fluidized bed dense phase fluidized bed Riser crude oil LCO LCO LCO Reaction pressure, MPa 1.0 1.0 0.3 Hydrogen partial pressure, MPa ～ 0.8 ～ Reactor inlet temperature, °C 680 680 680 Reactor outlet temperature, °C 520 520 520 Catalyst / feedstock oil weight ratio 30 30 9.5 Oil and gas residence time, s 6.0 6.0 1.5 <![CDATA[H2 / 循环油的体积比]]> ～ 800 ～ Weight ratio of atomizing steam / total raw materials 0.1 0.1 0.1 Particle concentration, % 30 30 ～ Air velocity, m / s 1 1 ～ <![CDATA[颗粒循环速率,kg / m 2 s]]> 200 200 ～ Product yield, weight % cracked gas 26.5 29.1 25.1 gasoline 54.2 55.6 53.5 diesel fuel 3.9 2.9 4.4 Oil slurry 4.8 3.9 5.9 coke 10.6 8.5 11.1 total 100.0 100.0 100.0 Ethylene + propylene + butene 14.9 16.8 14.1 BTX 16.4 18.7 15.2

Claims

1. A method for producing light olefins and aromatics by catalytic cracking, comprising: In the riser reactor, the heavy crude oil is subjected to non-hydrocatalytic cracking in the presence of a first catalyst, the oil and gas after the reaction enter a first separation system for separation, the first spent catalyst after the reaction enters a first regenerator for regeneration, and the regenerated first catalyst is circulated back to the riser reactor; In a dense phase fluidized bed reactor, a second feedstock is subjected to catalytic cracking in the presence of a second catalyst, the oil and gas after the reaction enter a second separation system for separation, the second spent catalyst after the reaction is depressurized through a lock hopper and then enters a second regenerator for regeneration, and the regenerated second regenerated catalyst after pressurization through a lock hopper is circulated back to the dense phase fluidized bed reactor; In the dense phase fluidized bed reactor, the particle concentration is 15-50%; the gas velocity is 0.1-15m / s, and the catalyst circulation rate is 200-1000kg / m 2 s; reaction temperature is 500-700 ° C, reaction pressure is 0.1-2.0 MPa, agent-oil ratio is 5-100, hydrogen-oil volume ratio is 100-1500, residence time is 0.1-20 seconds; The first catalyst and the second catalyst are catalytic cracking catalysts with aromatization function; In a dense-phase fluidized bed reactor, a second raw oil is subjected to catalytic cracking in the presence of a second catalyst under hydrogen conditions. The dense-phase fluidized bed reactor has a structure with a thin top and a coarse bottom. A small-diameter conveying bed is connected in series at the top outlet of the dense-phase fluidized bed and steam is supplemented. The diameter ratio of the lower coarse-diameter fluidized bed to the upper fine-diameter conveying bed is 2-10:1, and the height ratio of the lower coarse-diameter fluidized bed to the upper fine-diameter conveying bed is 1-15:

1.

2. The method according to claim 1, wherein The first regenerator and the second regenerator are the same regenerator.

3. The method according to claim 1, wherein The first catalyst and the second catalyst are the same catalyst.

4. The method according to any one of claims 1 to 3, wherein In the riser reactor, the reaction temperature is 500-700° C., the reaction pressure is 0.1-2.0 MPa, the weight ratio of the catalyst to the feedstock oil is 5-100, and the residence time is 0.1-20 seconds.

5. The method according to claim 1, wherein The catalytic cracking catalyst with aromatization function comprises large-pore zeolite and oxide, and optionally medium-pore zeolite and optionally clay.

6. The method according to claim 5, wherein: The catalytic cracking catalyst with aromatization function includes medium-pore zeolite and large-pore zeolite modified with metal elements and / or non-metal elements as active components, the metal elements used for modification are selected from Fe, Co, Ni, Cu, Zn and rare earth metals, and the non-metal elements are selected from P.

7. The method according to claim 1, wherein The second feedstock oil is selected from heavy feedstock oil and light feedstock oil.

8. The method according to claim 7, wherein: The heavy feedstock oil is various heavy petroleum hydrocarbons with a carbon number greater than 20; the light feedstock oil includes straight-run diesel and light cycle oil (LCO).

9. The method according to claim 8, wherein The heavy petroleum hydrocarbons include wax oil and residual oil.

10. The method according to claim 8, wherein The light crude oil includes hydrogenated straight-run diesel and hydrogenated light cycle oil HLCO.

11. A reaction system for producing light olefins and aromatics by catalytic cracking for implementing the method according to claim 1, comprising: A riser reactor system comprising: a riser reactor, a riser top cyclone separator, and a riser stripper, wherein the riser top cyclone separator is disposed at the top of the riser reactor and is in communication with the riser stripper, so that the first spent catalyst separated by the riser top cyclone separator is stripped in the riser stripper; Dense phase fluidized bed reactor system, comprising: Dense phase fluidized bed reactor, dense phase fluidized bed cyclone separators, and Dense phase fluidized bed stripper, The dense phase fluidized bed cyclone separator is disposed on the top of the dense phase fluidized bed reactor and is in communication with the dense phase fluidized bed stripper, so that the second spent catalyst separated by the dense phase fluidized bed cyclone separator is stripped in the dense phase fluidized bed stripper; a lock hopper, wherein the dense phase fluidized bed stripper is in communication with the lock hopper, so that the second spent catalyst stripped by the dense phase fluidized bed stripper enters the lock hopper for depressurization; the lock hopper is also in communication with the dense phase fluidized bed reactor, so that the regenerated catalyst pressurized by the lock hopper is circulated back to the dense phase fluidized bed reactor; Regenerator, The riser stripper is connected to the regenerator, so that the first catalyst to be regenerated after being stripped by the riser stripper enters the regenerator for regeneration; the regenerator is also connected to the riser reactor, so that the regenerated catalyst regenerated by the regenerator is circulated back to the riser reactor; The regenerator is also connected to the lock hopper, so that the second catalyst to be regenerated that has been depressurized through the lock hopper enters the regenerator for regeneration, and the regenerated catalyst that has been regenerated through the regenerator is circulated back to the lock hopper.

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