Method and system for producing low-carbon olefins and aromatic hydrocarbons by direct catalytic cracking of crude oil

Abstract

The invention relates to a method and a system for producing low-carbon olefin and aromatic hydrocarbon by direct catalytic cracking of crude oil, and the method comprises the following steps: carrying out catalytic cracking reaction on the crude oil in a first fluidization reactor, carrying out catalytic cracking reaction on components difficult to convert in a second fluidization reactor, and carrying out gas-solid separation on a reaction product and a spent catalyst to obtain the low-carbon olefin and aromatic hydrocarbon. The spent catalyst is sequentially subjected to steam stripping, green coke supplementation and charring regeneration and then returns to the reactor for recycling; and separating the reaction product to obtain ethylene, propylene, a difficult-to-convert component and other products, wherein the difficult-to-convert component enters the second fluidization reactor to be further subjected to catalytic cracking reaction to obtain ethylene and propylene. When the catalytic cracking method and system are used for the catalytic cracking reaction of crude oil, chemical raw materials such as low-carbon olefins and light aromatic hydrocarbons can be produced with high selectivity, and efficient utilization of crude oil resources is realized.

Description

Technical Field

[0001] The present application relates to the field of petrochemical industry, and in particular, to a method and system for producing low-carbon olefins and aromatics by direct catalytic cracking of crude oil. Background Art

[0002] Refining capacity is in excess, and demand for refined oil products is slowing down. Ethylene, propylene and BTX (benzene-toluene-xylene) are key basic organic synthetic raw materials with huge demand, while demand for chemical products remains strong. The existing technical route for producing propylene and BTX from petroleum is developed on the basis of the traditional petroleum refining process that mainly produces oil products. There are problems such as long production process, low chemical yield and insignificant economic benefits. The technical measure to solve this problem is to develop key core technologies that mainly produce chemicals and can direct the conversion of crude oil hydrocarbon molecules into chemicals. Therefore, in recent years, international petrochemical companies represented by ExxonMobil and Saudi Aramco have begun to innovate traditional refining processes. These companies have subverted the traditional refining process and elevated the integration of refining and chemical production to a new level of direct production of chemicals from crude oil. 。

[0003] ExxonMobil Corporation of the United States is a pioneer in the research and development of crude oil steam cracking to produce olefins, and is the first company to build an industrial demonstration unit. It has also applied for a series of patents, such as CN101583697. The process method of the company's crude oil direct chemicals is that the crude oil directly enters the steam cracking furnace, and the light components and recombinant components are separated through flash evaporation. The light components (gaseous components) enter the steam cracking furnace for cracking, and the recombinant components (liquid components) are used as refinery raw materials. If the selected crude oil is light enough, there is no fraction above 593°C, that is, no bottom residue oil, and it does not need to rely on a refinery. The company's first industrial unit uses ultra-light paraffin-based tapis crude oil with an API gravity of 42.7 as raw material.

[0004] The technical characteristics of Saudi Aramco National Oil Company are that it adopts crude oil pretreatment technology and hydroprocessing technology to minimize the impact of non-volatile components in crude oil on steam cracking. At the same time, a vapor-liquid (steam and liquid) separation device is installed between the convection section and the radiation section of the steam cracking furnace to remove non-volatile liquid (liquid phase), ensuring that the material entering the radiation section does not carry liquid, thereby ensuring that the furnace tube does not coke, and the heavy components enter the catalytic cracking unit. It can be said that it is a process for producing olefins and aromatics from crude oil that integrates hydroprocessing, steam cracking and catalytic cracking processes.

[0005] Sinopec's crude oil-to-chemicals technology is mainly divided into two technical routes. One is crude oil steam cracking technology, which uses light crude oil as raw material and has a chemical yield of about 50%. The other is catalytic cracking technology. After desalting and dehydrating, the crude oil is divided into light and heavy components. The light component, i.e., light feed, and the heavy component, i.e., heavy feed, are respectively placed in two catalytic cracking reactors, where they are contacted with a high-temperature catalyst under a steam atmosphere to react to produce high value-added products. Alternatively, the light component and the heavy feed are reacted in different reaction zones of the same reactor. The total yield of low-carbon olefins and light aromatics is as high as over 50%.

[0006] Due to the presence of heavy components in crude oil that are difficult to vaporize, the existing crude oil direct chemical technology is only suitable for low-sulfur paraffin-based crude oil with an API degree of about 45. Other crude oil chemical technologies are different according to the different processing processes of heavy components in crude oil. The crude oil chemical technology routes of major companies are different, but they all use fraction cutting and combine process technologies according to the properties of distillate oils with different distillation ranges to achieve crude oil production chemicals. Compared with the traditional refining process, only the distillation range and quantity of the cut distillate oils are changed, and then the existing processing technology is integrated, which fails to achieve fundamental technological changes. In addition, these existing combined technologies are more suitable for light crude oil or paraffin-based crude oil. When heavy crude oil or intermediate-based crude oil is used as raw material, the yield of high value-added products such as low-carbon olefins and aromatics and other chemical raw materials is low. Summary of the invention

[0007] The purpose of the present application is to provide a method and system for producing high value-added products by catalytic cracking of crude oil to produce light olefins and aromatics, which not only has good crude oil adaptability and high yield of light olefins and aromatics, but also can solve the problem of insufficient heat in the potential catalytic cracking reaction of high-quality crude oil.

[0008] The first aspect of the present invention provides a method for producing light olefins and aromatics by direct catalytic cracking of crude oil, comprising:

[0009] (1) the feedstock oil and the first regenerated catalyst from the regenerator enter the first fluidized bed reactor for catalytic cracking reaction to obtain a first oil agent mixture comprising a first reaction product and a first catalyst to be regenerated;

[0010] (2) the second regenerated catalyst from the regenerator and the fresh catalyst enter the catalyst mixing zone of the second fluidized bed reactor, are mixed, and then contact with the difficult-to-convert component and undergo a catalytic cracking reaction to obtain a second oil agent mixture containing a second reaction product and a second catalyst to be regenerated;

[0011] (3) the first oil agent mixture and the second oil agent mixture enter the oil agent separation device for gas-solid separation, and the separated reaction oil gas is led out of the device for further separation to obtain ethylene, propylene, aromatics, difficult-to-convert components and other products;

[0012] (4) the separated spent catalyst is stripped and then enters the coking device, where it is mixed with the third regenerated catalyst from the regenerator and heated, and then contacts with the coking raw material to generate a coking reaction, thereby obtaining a spent catalyst with coke;

[0013] (5) The regenerated catalyst with coke enters the regenerator, contacts with oxygen-containing gas to generate carbonization reaction, and the first part of the regenerated catalyst returns to the first fluidized reactor for reaction circulation, and the second part of the regenerated catalyst enters the catalyst mixing zone of the second fluidized reactor to mix with fresh catalyst for reaction circulation;

[0014] The feedstock oil is full-fraction crude oil, and the difficult-to-convert components are light hydrocarbons or light distillate oil produced by the device itself or by other devices.

[0015] The method according to the first aspect, wherein the feedstock oil is a full-fraction crude oil from a conventional source;

[0016] Preferably, the feedstock oil also includes optional mineral oil and / or synthetic oil, the mineral oil is selected from one or more of coal liquefaction oil, oil sand oil and shale oil, and the synthetic oil is a distillate oil obtained by FT synthesis of coal, natural gas or asphalt.

[0017] The method according to the first aspect, wherein the light hydrocarbons include a gaseous hydrocarbon product rich in C4 fraction produced by the device itself and a gaseous hydrocarbon rich in C4 fraction produced by other devices, wherein the content of C4 olefins in the gaseous hydrocarbon rich in C4 fraction is greater than 50% by weight;

[0018] Preferably, the difficult-to-convert component is the C4 fraction produced by the device itself.

[0019] According to the method described in the first aspect, the light distillate oil is selected from one or more of the following: light distillate oil with a final boiling point of less than 280-350°C produced by the device; straight-run naphtha, straight-run kerosene, and straight-run diesel from other primary processing devices; other secondary processed topped oil, raffinate oil, hydrocracking light naphtha, pentane oil, coker gasoline, Fischer-Tropsch synthetic oil, catalytic cracking light gasoline, hydrogenated gasoline, and hydrogenated diesel.

[0020] The method according to the first aspect, wherein the first fluidized bed reactor is selected from one or more of a turbulent bed reactor, a fast bed reactor, and a dilute phase transport bed reactor in series; and / or

[0021] The second fluidized bed reactor is a dilute phase transport bed reactor.

[0022] According to the method of the first aspect, the catalytic cracking reaction conditions in the first fluidized bed reactor are:

[0023] The reaction temperature is 510-650°C;

[0024] The reaction time is 1-20 seconds;

[0025] The weight ratio of catalyst to crude oil is (3-50):1; and / or

[0026] The reaction pressure is 130-450 kPa;

[0027] Preferably, the crude oil enters the first fluidized bed reactor after being preheated and steam atomized, the preheating temperature is 180-350° C., and the water-oil weight ratio is (0.03-0.8):1.

[0028] The method according to the first aspect, wherein one or more inlets for difficult-to-convert components are provided on the second fluidized reactor;

[0029] Preferably, the one or more difficult-to-convert component inlets are independently arranged at the outlet end of the catalyst mixing zone of the second fluidized reactor or in the middle and upstream of the second fluidized reactor, and the light hydrocarbons and light distillate oil of the difficult-to-convert component are introduced into the second fluidized reactor at the same or different difficult-to-convert component inlets;

[0030] More preferably, the light hydrocarbons of the difficult-to-convert components are introduced into the second fluidized reactor at one or more difficult-to-convert components inlets upstream of the light distillate oil introduction position.

[0031] According to the method of the first aspect, the catalytic cracking reaction conditions in the second fluidized bed reactor are:

[0032] The reaction temperature is 580-750°C;

[0033] Response time is 0.05-5 seconds; and / or

[0034] The weight ratio of catalyst to raw oil is (1-50):1;

[0035] Preferably, the difficult-to-convert components are introduced into the second fluidized bed reactor after being steam atomized, and the weight ratio of water vapor to crude oil is (0.03-0.5):1.

[0036] The method according to the first aspect, wherein the weight ratio of fresh catalyst to regenerated catalyst in the catalyst mixing zone of the second fluidized bed reactor is 0.01-0.3:1.

[0037] The method according to the first aspect, wherein the outlet temperature of the coke generator is 550-650° C., and / or the line speed is 1.2-2.2 m / s.

[0038] The second aspect of the present invention provides a system for producing light olefins by direct catalytic cracking of crude oil, comprising:

[0039] The catalytic cracking reaction unit comprises:

[0040] A first fluidized reactor is provided with a first pre-lifting medium inlet, a first regenerated catalyst inlet, a feedstock oil inlet and a first oil-agent mixture outlet;

[0041] The second fluidized reactor is provided with a catalyst mixing zone, one or more inlets for difficult-to-convert components and an outlet for a second oil-agent mixture, wherein the catalyst mixing zone is provided with a second pre-lifting medium inlet, a second regenerated catalyst inlet and a fresh catalyst inlet;

[0042] an oil-agent separation device, the oil-agent separation device being connected to both the first oil-agent mixture outlet of the first fluidized reactor and the second oil-agent mixture outlet of the second fluidized reactor, so that the first oil-agent mixture from the first fluidized reactor and the second oil-agent mixture from the second fluidized reactor are separated into reaction oil gas and catalyst to be generated by the oil-agent separation device; and

[0043] A settler, used for settling and collecting the spent catalyst separated by the oil agent separation device, a stripping section is provided below the settler for stripping the spent catalyst, and the stripping section is provided with a spent catalyst outlet and a stripping medium inlet;

[0044] A reaction product separation unit, the reaction product separation unit is connected to the oil agent separation device, and is used to separate the reaction oil gas separated by the oil agent separation device into products including light olefins, aromatics and difficult-to-convert components;

[0045] Catalyst regeneration unit, including

[0046] A coking device, used for contacting the catalyst to be generated separated from the catalytic cracking reaction unit with the coking raw material to generate a coking reaction to obtain the catalyst to be generated with coke, which is provided with an inlet for the catalyst to be generated, an inlet for the fluidized medium, an inlet for the coking raw material, a first gas distributor, a catalyst distributor and an outlet for the coking catalyst, wherein the inlet for the catalyst to be generated is fluidically connected to the outlet for the catalyst to be generated of the stripping section of the settler;

[0047] A regenerator, wherein the regenerator is provided with a coking catalyst inlet, an oxygen-containing gas inlet, a second gas distributor, a cyclone separator, a regenerated flue gas pipeline and at least one regenerated catalyst outlet; the coking catalyst inlet of the regenerator is fluidly connected to the coking catalyst outlet of the coking catalyst; one regenerated catalyst outlet is connected to a first regenerated catalyst inlet of a first fluidized reactor for recycling a portion of the regenerated catalyst back to the first fluidized reactor; one regenerated catalyst outlet is connected to a second regenerated catalyst inlet of a catalyst mixing zone of a second fluidized reactor for introducing a portion of the regenerated catalyst into the catalyst mixing zone for mixing with fresh catalyst;

[0048] A regenerated catalyst circulation pipeline connecting the coking device and the regenerator is arranged between the coking device and the regenerator, so as to allow a part of the regenerated catalyst to enter the coking device and mix with the catalyst to be regenerated to react with the coking raw material.

[0049] According to the system of the second aspect, the distance between the connection port of the regeneration catalyst circulation pipe on the coke generator and the bottom of the coke generator is 5% to 10% of the height of the coke generator; and / or

[0050] The distance between the coke raw material inlet and the bottom of the coke generator is 20% to 50% of the height of the coke generator.

[0051] Compared with the prior art, the method and system of the present invention have the following beneficial effects:

[0052] 1) It can realize direct catalytic cracking of crude oil, reduce the crude oil distillation process, simplify the process and reduce operating costs.

[0053] 2) In the process of catalytic cracking of crude oil, the single-pass conversion rate is not pursued. The difficult-to-convert components in the reaction process are recycled. By setting up specific reaction zones, a higher overall conversion rate and higher selectivity for light olefins can be achieved.

[0054] 3) Setting up a coker can solve the problem of insufficient heat balance when processing high-quality crude oil.

[0055] By adopting the method of the present application, crude oil can be directly and efficiently produced into chemical raw materials such as ethylene and propylene, alleviating the situation of oversupply of refined oil products, promoting the deep integration of the oil refining and petrochemical industries, and promoting the high-quality development of the refining industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The specific embodiments of the present invention are used together to explain the present application, but do not constitute a limitation of the present application. In the accompanying drawings:

[0057] Figure 1 A schematic flow chart of a process for producing high value-added products from crude oil according to an embodiment of the present application.

[0058] Description of reference numerals:

[0059] 100, first fluidized reactor; 101, first pre-lifting medium inlet; 102, crude oil inlet; 103, first regenerated catalyst inlet; 104, first oil-agent mixture outlet; 200, settler; 201, stripping section; 202, stripping medium pipeline; 203, inclined pipe to be produced; 204, oil-agent separation device; 205, gas collecting chamber; 206, large oil and gas pipeline; 300, coke generator; 301, fluidized medium inlet; 302, fluidized medium inlet; 303, gas distributor; 304, coke generator Material inlet; 305, catalyst distributor; 400, regenerator; 401, oxygen-containing gas inlet; 402, main air distributor; 404, cyclone separator; 405, regenerated flue gas pipeline; 406, regenerated catalyst outlet; 500, second fluidized bed reactor; 501, second pre-lifting medium inlet; 502, fresh catalyst inlet; 503, second regenerated catalyst inlet; 504, light hydrocarbon inlet; 505, light distillate oil inlet; 506, catalyst mixing zone; 507, second oil agent mixture outlet. DETAILED DESCRIPTION

[0060] The present application is further described in detail below through the accompanying drawings and embodiments. Through these descriptions, the characteristics and advantages of the present application will become clearer and more specific.

[0061] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, 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 noted.

[0062] Any specific numerical value disclosed herein (including the endpoint of the numerical range) is not limited to the exact value of the numerical value, but should be understood to also cover values ​​close to the exact value, such as all possible numerical values ​​within the range of ±5% of the exact value. In addition, for the disclosed numerical range, the endpoint values ​​of the range, the endpoint values ​​and the specific point values ​​in the range, and the specific point values ​​can be arbitrarily combined to obtain one or more new numerical ranges, and these new numerical ranges should also be regarded as specifically disclosed herein.

[0063] In this article, low-carbon olefins are a general term for ethylene, propylene and butene, and light aromatics (BTX) are a general term for benzene (BTX), toluene (T) and xylene (X).

[0064] In the present application, the terms "upstream" and "downstream" are based on the flow direction of the reactants. For example, when the reactants flow from bottom to top, "upstream" means the position below, while "downstream" means the position above.

[0065] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the commonly understood meaning in the art, the definition herein shall prevail.

[0066] 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.

[0067] The present invention provides a method for producing low-carbon olefins and aromatics by direct catalytic cracking of crude oil, which comprises:

[0068] (1) the feedstock oil and the first regenerated catalyst from the regenerator enter the first fluidized bed reactor for catalytic cracking reaction to obtain a first oil agent mixture comprising a first reaction product and a first catalyst to be regenerated;

[0069] (2) the second regenerated catalyst from the regenerator and the fresh catalyst enter the catalyst mixing zone of the second fluidized bed reactor, are mixed, and then contact with the difficult-to-convert component and undergo a catalytic cracking reaction to obtain a second oil agent mixture containing a second reaction product and a second catalyst to be regenerated;

[0070] (3) the first oil agent mixture and the second oil agent mixture enter the oil agent separation device for gas-solid separation, and the separated reaction oil gas is led out of the device for further separation to obtain ethylene, propylene, aromatics, difficult-to-convert components and other products;

[0071] (4) the separated spent catalyst is stripped and then enters the coking device, where it is mixed with the third regenerated catalyst from the regenerator and heated, and then contacts with the coking raw material to generate a coking reaction, thereby obtaining a spent catalyst with coke;

[0072] (5) The regenerated catalyst with coke enters the regenerator, contacts with oxygen-containing gas to generate carbonization reaction, and the first part of the regenerated catalyst returns to the first fluidized reactor for reaction circulation, and the second part of the regenerated catalyst enters the catalyst mixing zone of the second fluidized reactor to mix with fresh catalyst for reaction circulation;

[0073] The feedstock oil is full-fraction crude oil, and the difficult-to-convert components are light hydrocarbons or light distillate oil produced by the device itself or by other devices.

[0074] The present application will be further described below with reference to the preferred implementation modes shown in the accompanying drawings, but the present application is not limited thereby.

[0075] Figure 1A preferred embodiment of the catalytic cracking method of the present application is provided, wherein the first fluidized reactor 100 is provided with a first pre-lifting medium inlet 101, a first regenerated catalyst inlet 103, and a crude oil inlet 102 in order from bottom to top. The second fluidized reactor 500 is provided with a bottom catalyst mixing zone 506, a lower light hydrocarbon inlet 504, and a mid-upstream light distillate oil inlet 505. The catalyst mixing zone 506 is provided with a second pre-lifting medium inlet 501, a fresh catalyst inlet 502, and a second regenerated catalyst inlet 503.

[0076] The pre-lifting medium enters the bottom of the first fluidized reactor 100 through the first pre-lifting medium inlet 101. The lifting medium can be dry gas, water vapor or a mixture thereof, which mixes with the hot regenerated catalyst from the first regenerated catalyst inlet 103 and moves upward. The reaction raw materials such as preheated crude oil and atomized steam are injected into the lower part of the first fluidized reactor 100 through the crude oil inlet 102, mixed with the high-temperature regenerated catalyst and subjected to catalytic cracking reaction;

[0077] The hot regenerated catalyst from the second regenerated catalyst inlet 503 and the fresh catalyst from the fresh catalyst inlet 502 enter the catalyst mixing zone 506 at the bottom of the second fluidized reactor 500, move upward and are fully mixed under the lifting action of the pre-lifting medium from the second pre-lifting medium inlet 501, and the mixed catalyst contacts the difficult-to-convert raw materials such as light hydrocarbons and atomized steam introduced through the light hydrocarbon inlet 504 at the outlet of the catalyst mixing zone 506 and undergoes catalytic cracking reaction, and the generated oil-agent mixture moves upward, contacts the difficult-to-convert components such as light distillate oil introduced through pipeline 505 and undergoes catalytic cracking reaction.

[0078] The reaction oil gas and the catalyst to be generated by the catalytic cracking reaction of the first fluidized reactor and the second fluidized reactor flow upward through the first oil-agent mixture outlet 104 and the second oil-agent mixture outlet 507 respectively and enter the oil-agent separation device 204 such as a cyclone separator for gas-solid separation. The reaction oil gas obtained by separation is led out of the device through the gas collecting chamber 205 and the large oil-gas pipe 206 and enters the subsequent separation system; the catalyst to be generated obtained by separation enters the lower stripping section 201 of the settler 200, and after being stripped by the stripping medium from the stripping medium pipeline 202, it enters the coker 300 through the inclined pipe 203 to be generated.

[0079] The fluidizing medium enters the coke generator 300 from the bottom of the coke generator 300 through the fluidizing medium inlet 301 and the gas distributor 302. The fluidizing medium may be nitrogen, water vapor or a mixture thereof. The high-temperature regenerated catalyst from the external catalyst circulation pipe 303 enters the lower part of the coking device 300, mixes with the fluidizing gas and moves upward, contacts the catalyst to be regenerated from the inclined pipe 203 to be regenerated and continues to move upward, contacts the supplementary fuel oil from the coking raw material inlet 304 and undergoes a coking reaction; the catalyst with charcoal and coke flows upward, enters the regenerator 400 through the catalyst distributor 305, contacts the oxygen-containing gas injected through the oxygen-containing gas inlet 401 and the main air distributor 402 and undergoes a complete combustion reaction, completely releasing heat, and the regenerated catalyst is sent out of the regenerator through the regenerated catalyst outlet 406, a part of the regenerated catalyst is supplied to the first fluidized reactor for circulation through the first regenerated catalyst inlet 103, and a part of the regenerated catalyst is supplied to the second fluidized reactor through the second regenerated catalyst inlet 503; the regenerated flue gas is separated from the entrained catalyst by the cyclone separator 404 and enters the energy recovery system through the regenerated flue gas pipeline 405.

[0080] The process provided in the present application is applicable to crude oil selected from one or a mixture of crude oil, mineral oil and synthetic oil. The crude oil is a full-fraction crude oil from conventional sources, the mineral oil is selected from one or a mixture of one or more of coal liquefied oil, oil sand oil and shale oil, and the synthetic oil is a distillate obtained by FT synthesis of coal, natural gas or asphalt.

[0081] In the present application, the difficult-to-convert components are light hydrocarbons or light distillate oils from this device or from outside.

[0082] In one embodiment, the light hydrocarbon in the difficult-to-convert components is a C4 component, which refers to a low molecular hydrocarbon compound that exists in gaseous form at room temperature and pressure with C4 fraction as the main component, including alkanes, olefins and alkynes with 4 carbon atoms in the molecule. It includes gaseous hydrocarbon products rich in C4 fraction produced by the device of the present invention, and may also include gaseous hydrocarbons rich in C4 fraction produced by other device processes, among which the C4 fraction produced by the device of the present invention is preferred. The C4 hydrocarbons are preferably C4 fractions rich in olefins, wherein the content of C4 olefins is greater than 50% by weight, preferably greater than 60% by weight, and preferably above 70% by weight.

[0083] In one embodiment, the feedstock oil is a whole fraction crude oil from a conventional source;

[0084] Preferably, the feedstock oil also includes optional mineral oil and / or synthetic oil, the mineral oil is selected from one or more of coal liquefaction oil, oil sand oil and shale oil, and the synthetic oil is a distillate oil obtained by FT synthesis of coal, natural gas or asphalt.

[0085] In one embodiment, the light hydrocarbons include a gaseous hydrocarbon product rich in C4 fraction produced by the device itself and a gaseous hydrocarbon rich in C4 fraction produced by other devices, wherein the content of C4 olefins in the gaseous hydrocarbon rich in C4 fraction is greater than 50% by weight;

[0086] Preferably, the difficult-to-convert component is the C4 fraction produced by the device itself.

[0087] In one embodiment, the light distillate oil is selected from one or more of the following: light distillate oil with a final boiling point of less than 280-350°C produced by the device; straight-run naphtha, straight-run kerosene, and straight-run diesel from other primary processing devices; other secondary processed topped oil, raffinate oil, hydrocracking light naphtha, pentane oil, coker gasoline, Fischer-Tropsch synthetic oil, catalytic cracking light gasoline, hydrogenated gasoline, and hydrogenated diesel.

[0088] In one embodiment, the first fluidized bed reactor is selected from a series of one or more of a turbulent bed reactor, a fast bed reactor, and a dilute phase transport bed reactor; and / or

[0089] The second fluidized bed reactor is a dilute phase transport bed reactor.

[0090] In one embodiment, the first fluidized bed reactor is selected from one or more combinations of turbulent bed, fast bed and dilute phase conveying bed. It can be one or two series combinations of reactors with constant linear speed, constant diameter, variable diameter, upward conveying line and downward conveying line. In order to allow the crude oil to react fully and according to different quality requirements of the target product, the reaction zones can be 2-8, preferably 2-3. The gas velocity of the turbulent bed and fast bed reactors is 0.1 m / s-2 m / s, and the gas velocity of the dilute phase conveying bed is 2 m / s-20 m / s.

[0091] In one embodiment, the second fluidized bed reactor is selected from a dilute phase transport bed reactor. The dilute phase transport bed reactor can be a conventional constant diameter reactor or a reactor with various forms of variable diameters.

[0092] In one embodiment, the catalytic cracking reaction conditions in the first fluidized reactor are:

[0093] The reaction temperature is 510-650°C;

[0094] The reaction time is 1-20 seconds;

[0095] The weight ratio of catalyst to crude oil is (3-50):1; and / or

[0096] The reaction pressure is 130-450 kPa;

[0097] Preferably, the crude oil enters the first fluidized bed reactor after being preheated and steam atomized, the preheating temperature is 180-350° C., and the water-oil weight ratio is (0.03-0.8):1.

[0098] In the present application, the catalytic cracking reaction temperature of the first fluidized bed reactor refers to the reactor outlet temperature.

[0099] In one embodiment, one or more inlets for difficult-to-convert components are provided on the second fluidized reactor;

[0100] Preferably, the one or more difficult-to-convert component inlets are independently arranged at the outlet end of the catalyst mixing zone of the second fluidized reactor or in the middle and upstream of the second fluidized reactor, and the light hydrocarbons and light distillate oil of the difficult-to-convert component are introduced into the second fluidized reactor at the same or different difficult-to-convert component inlets;

[0101] More preferably, the light hydrocarbons of the difficult-to-convert components are introduced into the second fluidized reactor at one or more difficult-to-convert components inlets upstream of the light distillate oil introduction position.

[0102] In one embodiment, the second fluidized bed reactor is provided with one or more, for example, one, two or more difficult-to-convert raw material inlets, and the one or more difficult-to-convert raw material inlets can be independently arranged at the lower part of the second fluidized bed reactor. Further preferably, the difficult-to-convert raw material inlets are independently arranged in the middle and upstream of the catalytic cracking reactor.

[0103] In one embodiment, the light hydrocarbons and light distillate oil of the difficult-to-convert components can be introduced into the second fluidized bed reactor at the same position, or can be introduced into the second fluidized bed reactor at different positions. Preferably, the light hydrocarbons are introduced into the second fluidized bed reactor at one or more positions downstream of the light distillate oil introduction position.

[0104] In one embodiment, the catalytic cracking reaction conditions in the second fluidized reactor are:

[0105] The reaction temperature is 580-750°C;

[0106] Response time is 0.05-5 seconds; and / or

[0107] The weight ratio of catalyst to raw oil is (1-50):1;

[0108] Preferably, the difficult-to-convert components are introduced into the second fluidized bed reactor after being steam atomized, and the weight ratio of water vapor to crude oil is (0.03-0.5):1.

[0109] In one embodiment, the weight ratio of fresh catalyst to regenerated catalyst in the catalyst mixing zone of the second fluidized bed reactor is 0.01-0.3:1.

[0110] In one embodiment, the outlet temperature of the coke generator is 550-650° C., and / or the line speed is 1.2-2.2 m / s.

[0111] In one embodiment, the atomizing medium of the coke generator is nitrogen, and the mass ratio of the atomizing medium to the combustion oil is 1:1 to 1:100.

[0112] In one embodiment, the temperature in the regenerator is 550-750°C, more preferably 600-730°C, and further preferably 650-700°C; the gas superficial linear velocity is 0.3-3 m / s, preferably 0.5-2.5 m / s, and more preferably 0.6-1.5 m / s; the average residence time of the catalyst to be regenerated is 0.6-8 minutes, preferably 0.8-6 minutes, and more preferably 1-5 minutes.

[0113] In one embodiment, the catalyst of the present invention comprises, on a dry basis and based on the dry weight of the catalyst, 1-50 wt%, preferably 5-45 wt%, more preferably 10-40 wt% zeolite; 5-99 wt%, preferably 10-80 wt%, more preferably 20-70 wt% inorganic oxide, and 0-70 wt%, preferably 5-60 wt%, more preferably 10-50 wt% clay.

[0114] In one embodiment, the zeolite includes a medium-pore zeolite and an optional large-pore zeolite, wherein the medium-pore zeolite is selected from ZSM series zeolites, ZRP zeolites, and any combination thereof; the large-pore zeolite is selected from rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite and high silicon Y-type zeolite, and any combination thereof.

[0115] In one embodiment, the medium pore zeolite accounts for 10-90 wt %, preferably 50-80 wt %, of the total weight of the zeolite on a dry basis.

[0116] In the present application, the medium-pore zeolite and large-pore zeolite follow the conventional definition in the art, that is, the average pore diameter of the medium-pore zeolite is about 0.5-0.6 nm, and the average pore diameter of the large-pore zeolite is about 0.7-1.0 nm.

[0117] As an example, the large-pore zeolite can be selected from one or more of rare earth Y (REY) type zeolite, rare earth hydrogen Y (REHY) type zeolite, ultrastable Y type zeolite obtained by different methods and high silicon Y type zeolite. The medium-pore zeolite can be selected from zeolites with MFI structure, such as ZSM series zeolites and / or ZRP zeolites. Optionally, the above-mentioned medium-pore zeolites can also be modified with non-metallic elements such as phosphorus and / or transition metal elements such as iron, cobalt, and nickel. A more detailed description of ZRP zeolite can be found in U.S. Patent No. 5,232,675A. ZSM series zeolites are preferably selected from one or more mixtures of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and other zeolites of similar structure. A more detailed description of ZSM-5 can be found in U.S. Patent No. 3,702,886A.

[0118] According to the present application, the inorganic oxide is used as a binder, preferably silicon dioxide (SiO2) and / or aluminum oxide (Al2O3). The clay is used as a matrix (ie, a carrier), preferably kaolin and / or halloysite.

[0119] According to the present application, the method of separating the reaction products to obtain cracking gas, cracking light gasoline, cracking light distillate oil, and cracking heavy oil is also well known to those skilled in the art. The cracking gas can be further separated by conventional separation means in the art to obtain target products such as ethylene and propylene and C4 components.

[0120] According to the present application, the oil agent separation equipment and the reaction product separation equipment are both well known to those skilled in the art. For example, the oil agent separation equipment may include a cyclone separator, a settler and a stripper, etc., and the reaction product separation equipment may be a distillation tower, etc.

[0121] The present invention also provides a system for producing light olefins by direct catalytic cracking of crude oil, comprising:

[0122] The catalytic cracking reaction unit comprises:

[0123] A first fluidized reactor is provided with a first pre-lifting medium inlet, a first regenerated catalyst inlet, a feedstock oil inlet and a first oil-agent mixture outlet;

[0124] The second fluidized reactor is provided with a catalyst mixing zone, one or more inlets for difficult-to-convert components and an outlet for a second oil-agent mixture, wherein the catalyst mixing zone is provided with a second pre-lifting medium inlet, a second regenerated catalyst inlet and a fresh catalyst inlet;

[0125] an oil-agent separation device, the oil-agent separation device being connected to both the first oil-agent mixture outlet of the first fluidized reactor and the second oil-agent mixture outlet of the second fluidized reactor, so that the first oil-agent mixture from the first fluidized reactor and the second oil-agent mixture from the second fluidized reactor are separated into reaction oil gas and catalyst to be generated by the oil-agent separation device; and

[0126] A settler, used for settling and collecting the spent catalyst separated by the oil agent separation device, a stripping section is provided below the settler for stripping the spent catalyst, and the stripping section is provided with a spent catalyst outlet and a stripping medium inlet;

[0127] A reaction product separation unit, the reaction product separation unit is connected to the oil agent separation device, and is used to separate the reaction oil gas separated by the oil agent separation device into products including light olefins, aromatics and difficult-to-convert components;

[0128] Catalyst regeneration unit, including

[0129] A coking device, used for contacting the catalyst to be generated separated from the catalytic cracking reaction unit with the coking raw material to generate a coking reaction to obtain the catalyst to be generated with coke, which is provided with an inlet for the catalyst to be generated, an inlet for the fluidized medium, an inlet for the coking raw material, a first gas distributor, a catalyst distributor and an outlet for the coking catalyst, wherein the inlet for the catalyst to be generated is fluidically connected to the outlet for the catalyst to be generated of the stripping section of the settler;

[0130] A regenerator, wherein the regenerator is provided with a coking catalyst inlet, an oxygen-containing gas inlet, a second gas distributor, a cyclone separator, a regenerated flue gas pipeline and at least one regenerated catalyst outlet; the coking catalyst inlet of the regenerator is fluidly connected to the coking catalyst outlet of the coking catalyst; one regenerated catalyst outlet is connected to a first regenerated catalyst inlet of a first fluidized reactor for recycling a portion of the regenerated catalyst back to the first fluidized reactor; one regenerated catalyst outlet is connected to a second regenerated catalyst inlet of a catalyst mixing zone of a second fluidized reactor for introducing a portion of the regenerated catalyst into the catalyst mixing zone for mixing with fresh catalyst;

[0131] A regenerated catalyst circulation pipeline connecting the coking device and the regenerator is arranged between the coking device and the regenerator, so as to allow a part of the regenerated catalyst to enter the coking device and mix with the catalyst to be regenerated to react with the coking raw material.

[0132] In one embodiment, the distance between the connection port of the regenerated catalyst circulation pipe on the coke generator and the bottom of the coke generator is 5% to 10% of the height of the coke generator; and / or

[0133] The distance between the coke raw material inlet and the bottom of the coke generator is 20% to 50% of the height of the coke generator.

[0134] In the present application, the coker may be provided with one or more, for example, one, two or more fuel oil inlets, and the one or more fuel oil inlets may be independently provided at the outlet end of the coker, or at the bottom of the coker. Further preferably, the fuel oil inlets are independently provided at the middle and upstream of the coker. Further preferably, the distance between the fuel oil inlet and the bottom of the coker is independently 20% to 50% of the height of the coker. The fuel oil may include straight run distillate or secondary processed distillate. Preferably, the secondary processed distillate may be selected from a mixed oil of one or more of catalytic cracking diesel, catalytic cracking slurry, coker gasoline, coker diesel and coker gas oil.

[0135] In one embodiment, the fluidizing medium of the coke generator enters into the coke generator through a first gas distributor disposed at the bottom.

[0136] According to the present application, the first gas distributor may be a main air distributor known to those skilled in the art. For example, the main air distributor may be a distribution plate and a distribution pipe. Preferably, the distribution pipe is an annular distribution pipe and a dendrite distribution pipe.

[0137] In the present application, a catalyst distribution plate may be provided at the position where the catalyst enters the bottom of the regenerator, for example, at the outlet end of the coking device. According to the present application, the catalyst distribution plate may be a distribution plate of various types commonly used in the industry, for example, one or more of a flat plate, an arch, a dish, an annular shape, and an umbrella shape. The use of a catalyst distribution plate helps to make the catalyst uniformly contact with the oxygen-containing gas in the axial direction of the regenerator for a coking reaction, thereby improving the coking efficiency and reducing the occurrence of local hot spots in the catalyst bed.

[0138] By setting up a coking device, the injected fuel oil is mixed with the catalyst under low-temperature, oxygen-free fluidized conditions to form coke. The catalyst with coke attached is back-mixed in the coking device so that the coke is evenly distributed on the catalyst, which helps to achieve uniform distribution of catalyst surface temperature.

[0139] In one embodiment, a second gas distributor is provided at the bottom of the regenerator, so that the oxygen-containing gas injected through the oxygen-containing gas inlet enters the regenerator through the second gas distributor. According to the present application, the second gas distributor can adopt a main air distributor well known to those skilled in the art. For example, the main air distributor can be a distribution plate and a distribution pipe. Preferably, the distribution pipe is an annular distribution pipe and a dendrite distribution pipe.

[0140] The following examples will further illustrate the present application, but are not intended to limit the present application.

[0141] The raw material oil used in the following examples and comparative examples is Kuwait crude oil, and its properties are shown in Table 1. The catalyst used is a commercial catalytic cracking catalyst purchased from the Catalyst Branch of Sinopec, with a trade name of DMMC-2.

[0142] Example 1

[0143] Using the feedstock oil and DMMC-2 catalyst shown in Table 1, Figure 1 The experiment was carried out on the pilot plant shown in the figure, wherein the structure of the reactor used is as follows:

[0144] The first fluidized reactor and the second fluidized reactor both use riser reactors of equal diameter, wherein the total height of the first fluidized reactor is 7 meters and the inner diameter is 0.3 meters, the height of the second fluidized reactor is 7 meters and the inner diameter is 0.2 meters, wherein the height of the catalyst mixing zone is 1 meter, the inner diameter of the coke generator is 0.3 meters and the height is 2 meters; the distance between the coke raw material inlet 304 of the coke generator and the bottom of the coke generator is 30% of the height of the coke generator. The outlet of the coke generator is directly connected to the bottom opening of the regenerator, and a catalyst distributor is arranged at the outlet.

[0145] The hot regenerated catalyst at the first regenerated catalyst inlet 103 enters the lower part of the first fluidized reactor and moves upward under the action of the pre-lifting medium. The preheated crude oil and atomized steam are injected into the lower part of the first fluidized reactor through the feed pipeline, with a water-oil weight ratio of 0.2:1, and are mixed with the existing catalyst in the catalytic cracking reactor to carry out catalytic cracking reaction, generating the first reaction product and the catalyst to be regenerated.

[0146] The hot regenerated catalyst from the second regenerated catalyst inlet 503 and the fresh catalyst from the fresh catalyst inlet 502 enter the catalyst mixing zone 506, and move upward under the lifting effect of the pre-lifting medium injected through the second pre-lifting medium inlet 501. The carbon four fraction of the difficult-to-convert component enters the outlet of the catalyst mixing zone 506 through the light hydrocarbon inlet 504 with a water-oil weight ratio of 0.2:1, contacts the mixed catalyst and undergoes catalytic cracking reaction. The reaction oil mixture moves upward, contacts the light distillate oil of the difficult-to-convert component introduced through the light distillate oil inlet 505 and undergoes catalytic cracking reaction, thereby generating a second reaction product and a catalyst to be regenerated.

[0147] The first reaction product, the second reaction product and the catalyst to be generated enter the oil agent separation device 204 such as a cyclone separator for gas-solid separation. The reaction oil and gas obtained by separation are led out of the device through the gas collecting chamber 205 and the large oil and gas pipe 206 and enter the subsequent separation system; the catalyst with coke obtained by separation enters the lower part of the settler 200 and enters the coking device 300 through the inclined pipe 203 to be generated.

[0148] Nitrogen is introduced into the bottom of the coker 300, mixed with the regenerated catalyst and the catalyst to be regenerated in turn and moved upward to heat the catalyst to be regenerated; the coking raw material atomized by nitrogen is injected into the coker, the coking raw material is catalytic cracking diesel, and the mass ratio of the atomizing medium to the coking raw material fuel oil is 0.05:1, and it contacts with the flow in the coker and generates a coking reaction; the catalyst with coke enters the regenerator, contacts with the air to generate a complete combustion reaction, and the regenerated catalyst is returned to the first fluidized reactor and the second fluidized reactor for reaction circulation, and the regenerated flue gas enters the energy recovery system through pipeline 405.

[0149] The operating conditions and product distribution are listed in Table 2 and Table 3. As can be seen from Table 3, the ethylene yield of this embodiment reaches 7.78% by weight, the propylene yield reaches 19.11% by weight, and the total yield of light olefins and light aromatics is 45.83%.

[0150] Comparative Example 1

[0151] The crude oil and DMMC-2 catalyst shown in Table 1 were used to conduct the test on a medium-sized device. The reactor was a conventional riser reactor (first fluidized reactor) connected in series with a fluidized bed reactor (second fluidized reactor). The preheated crude oil entered the riser reaction zone and the fluidized bed reactor in turn to contact with the catalytic cracking catalyst for catalytic cracking reaction. After the reaction, the logistics entered the subsequent oil agent separation device and product separation equipment. The separated catalyst to be regenerated entered the lower part of the regenerator and contacted with the air distributed into the regenerator by the main air distributor to cause a scorching reaction. The raw coke material was injected into the catalyst dense phase bed. The raw coke material was scorched after contacting the high-temperature air and released heat. The regenerated catalyst returned to the reactor for recycling. The operating conditions and product distribution are listed in Tables 2 and 3.

[0152] From the results in Table 3, it can be seen that the ethylene yield of this comparative example reaches 5.56% by weight, the propylene yield reaches 15.85% by weight, and the total yield of low-carbon olefins and light aromatics is 39.04%.

[0153] It can be seen from the results of the above examples and comparative examples that when the catalytic cracking method and system of the present application are used for catalytic cracking of crude oil, the yield of light olefins is significantly improved, and the utilization rate of crude oil atoms is high. When the heat balance is insufficient, the use of a coker can make the coke combustion environment in the regenerator moderate and stable, and the radial and axial catalyst temperatures help maintain the physical and chemical properties of the catalyst.

[0154] The preferred embodiments of the present application are described in detail above; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

[0155] 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, this application will not further describe various possible combinations.

[0156] In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the content invented by the present application.

[0157] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0158] The present application has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, various replacements and improvements may be made to the present application, all of which fall within the scope of protection of the present application.

[0159] Table 1 Properties of crude oil used

[0160] Crude oil classification Intermediate base crude oil <![CDATA[Density (20 °C) / (kg / m 3 )]]> 887.5 Carbon content / weight% 84.33 Hydrogen content / weight% 11.82 Sulfur content / weight% 2.631 Nitrogen content / weight% 0.16 Carbon residue value / weight% 6.29 Metal content / (mg / kg) Fe 1.3 Ni 13 V 37 Na <0.1 Ca 0.2

[0161] Table 2 Reaction conditions of Example 1 and Comparative Example 1

[0162]

[0163]

[0164] Table 3 Comparison of reaction results between Example 1 and Comparative Example 1

[0165] Example 1 Comparative Example 1 Product distribution, weight % H2~C2 15.04 10.16 Ethylene 7.78 5.56 C3~C4 41.33 34.94 Of which propylene 19.11 15.85 Of which butene 10.79 11.29 gasoline 17.92 24.61 Among them, light aromatics 8.15 6.34 diesel fuel 11.09 14.08 heavy oil 4.01 3.09 Coke 10.61 13.12 total 100 100 Total yield of light olefins and light aromatics, weight % 45.83 39.04

Claims

1. A method for producing light olefins and aromatics by direct catalytic cracking of crude oil, comprising: (1) the feedstock oil and the first regenerated catalyst from the regenerator enter the first fluidized bed reactor for catalytic cracking reaction to obtain a first oil agent mixture comprising a first reaction product and a first catalyst to be regenerated; (2) the second regenerated catalyst from the regenerator and the fresh catalyst enter the catalyst mixing zone of the second fluidized bed reactor, are mixed, and then contact with the difficult-to-convert component and undergo a catalytic cracking reaction to obtain a second oil agent mixture containing a second reaction product and a second catalyst to be regenerated; (3) the first oil agent mixture and the second oil agent mixture enter the oil agent separation device for gas-solid separation, and the separated reaction oil gas is led out of the device for further separation to obtain ethylene, propylene, aromatics, difficult-to-convert components and other products; (4) the separated spent catalyst is stripped and then enters the coking device, where it is mixed with the third regenerated catalyst from the regenerator and heated, and then contacts with the coking raw material to generate a coking reaction, thereby obtaining a spent catalyst with coke; (5) The regenerated catalyst with coke enters the regenerator, contacts with oxygen-containing gas to generate carbonization reaction, and the first part of the regenerated catalyst returns to the first fluidized reactor for reaction circulation, and the second part of the regenerated catalyst enters the catalyst mixing zone of the second fluidized reactor to mix with fresh catalyst for reaction circulation; The feedstock oil is full-fraction crude oil, and the difficult-to-convert components are light hydrocarbons or light distillate oil produced by the device itself or by other devices.

2. The method according to claim 1, characterized in that The feedstock oil is a full-fraction crude oil from a conventional source; Preferably, the feedstock oil also includes optional mineral oil and / or synthetic oil, the mineral oil is selected from one or more of coal liquefaction oil, oil sand oil and shale oil, and the synthetic oil is a distillate oil obtained by FT synthesis of coal, natural gas or asphalt.

3. The method according to claim 1, characterized in that The light hydrocarbons include gaseous hydrocarbon products rich in C4 fraction produced by the device itself and gaseous hydrocarbons rich in C4 fraction produced by other devices, wherein the content of C4 olefins in the gaseous hydrocarbons rich in C4 fraction is greater than 50% by weight; Preferably, the difficult-to-convert component is the C4 fraction produced by the device itself.

4. The method according to claim 1, characterized in that: The light distillate oil is selected from one or more of the following: light distillate oil with a final boiling point of less than 280-350°C produced by the device; straight-run naphtha, straight-run kerosene, and straight-run diesel from other primary processing devices; other secondary processed topped oil, raffinate oil, hydrocracking light naphtha, pentane oil, coker gasoline, Fischer-Tropsch synthetic oil, catalytic cracking light gasoline, hydrogenated gasoline, and hydrogenated diesel.

5. The method according to claim 1, characterized in that: The first fluidized bed reactor is selected from one or more of a turbulent bed reactor, a fast bed reactor, and a dilute phase transport bed reactor in series; and / or The second fluidized bed reactor is a dilute phase transport bed reactor.

6. The method according to claim 1, characterized in that The catalytic cracking reaction conditions in the first fluidized reactor are: The reaction temperature is 510-650°C; The reaction time is 1-20 seconds; The weight ratio of catalyst to crude oil is (3-50):1; and / or The reaction pressure is 130-450 kPa; Preferably, the crude oil enters the first fluidized bed reactor after being preheated and steam atomized, the preheating temperature is 180-350° C., and the water-oil weight ratio is (0.03-0.8):

1.

7. The method according to claim 1, characterized in that The second fluidized reactor is provided with one or more inlets for difficult-to-convert components; Preferably, the one or more difficult-to-convert component inlets are independently arranged at the outlet end of the catalyst mixing zone of the second fluidized reactor or in the middle and upstream of the second fluidized reactor, and the light hydrocarbons and light distillate oil of the difficult-to-convert component are introduced into the second fluidized reactor at the same or different difficult-to-convert component inlets; More preferably, the light hydrocarbons of the difficult-to-convert components are introduced into the second fluidized reactor at one or more difficult-to-convert components inlets upstream of the light distillate oil introduction position.

8. The method according to claim 1, characterized in that: The catalytic cracking reaction conditions in the second fluidized reactor are: The reaction temperature is 580-750°C; Response time is 0.05-5 seconds; and / or The weight ratio of catalyst to raw oil is (1-50):1; Preferably, the difficult-to-convert components are introduced into the second fluidized bed reactor after being steam atomized, and the weight ratio of water vapor to crude oil is (0.03-0.5):

1.

9. The method according to claim 1, characterized in that: The weight ratio of fresh catalyst to regenerated catalyst in the catalyst mixing zone of the second fluidized bed reactor is 0.01-0.3:

1.

10. The method according to claim 1, characterized in that The outlet temperature of the coke generator is 550-650° C., and / or the linear speed is 1.2-2.2 m / s.

11. A system for producing light olefins by direct catalytic cracking of crude oil, comprising: The catalytic cracking reaction unit comprises: A first fluidized reactor is provided with a first pre-lifting medium inlet, a first regenerated catalyst inlet, a feedstock oil inlet and a first oil-agent mixture outlet; The second fluidized reactor is provided with a catalyst mixing zone, one or more inlets for difficult-to-convert components and an outlet for a second oil-agent mixture, wherein the catalyst mixing zone is provided with a second pre-lifting medium inlet, a second regenerated catalyst inlet and a fresh catalyst inlet; an oil-agent separation device, the oil-agent separation device being connected to both the first oil-agent mixture outlet of the first fluidized reactor and the second oil-agent mixture outlet of the second fluidized reactor, so that the first oil-agent mixture from the first fluidized reactor and the second oil-agent mixture from the second fluidized reactor are separated into reaction oil gas and catalyst to be generated by the oil-agent separation device; and A settler, used for settling and collecting the spent catalyst separated by the oil agent separation device, a stripping section is provided below the settler for stripping the spent catalyst, and the stripping section is provided with a spent catalyst outlet and a stripping medium inlet; A reaction product separation unit, the reaction product separation unit is connected to the oil agent separation device, and is used to separate the reaction oil gas separated by the oil agent separation device into products including light olefins, aromatics and difficult-to-convert components; Catalyst regeneration unit, including A coking device, used for contacting the catalyst to be generated separated from the catalytic cracking reaction unit with the coking raw material to generate a coking reaction to obtain the catalyst to be generated with coke, which is provided with an inlet for the catalyst to be generated, an inlet for the fluidized medium, an inlet for the coking raw material, a first gas distributor, a catalyst distributor and an outlet for the coking catalyst, wherein the inlet for the catalyst to be generated is fluidically connected to the outlet for the catalyst to be generated of the stripping section of the settler; A regenerator, wherein the regenerator is provided with a coking catalyst inlet, an oxygen-containing gas inlet, a second gas distributor, a cyclone separator, a regenerated flue gas pipeline and at least one regenerated catalyst outlet; the coking catalyst inlet of the regenerator is fluidly connected to the coking catalyst outlet of the coking catalyst; one regenerated catalyst outlet is connected to a first regenerated catalyst inlet of a first fluidized reactor for recycling a portion of the regenerated catalyst back to the first fluidized reactor; one regenerated catalyst outlet is connected to a second regenerated catalyst inlet of a catalyst mixing zone of a second fluidized reactor for introducing a portion of the regenerated catalyst into the catalyst mixing zone for mixing with fresh catalyst; A regenerated catalyst circulation pipeline connecting the coking device and the regenerator is arranged between the coking device and the regenerator, so as to allow a part of the regenerated catalyst to enter the coking device and mix with the catalyst to be regenerated to react with the coking raw material.

12. The system for producing light olefins by direct catalytic cracking of crude oil according to claim 11, characterized in that: The distance between the connection port of the regenerated catalyst circulation pipe on the coke generator and the bottom of the coke generator is 5% to 10% of the height of the coke generator; and / or The distance between the coke raw material inlet and the bottom of the coke generator is 20% to 50% of the height of the coke generator.

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