Methods and systems for direct catalytic cracking of crude oil to improve thermal balance

Abstract

A method and system for direct catalytic cracking of crude oil with improved thermal balance is disclosed. The method includes: a reduced, high-temperature regenerated catalyst entering the lower part of a first reactor to contact crude oil, then sequentially entering a first reactor and a second reactor of a catalytic cracking reactor to undergo catalytic cracking. After gas-solid separation, the spent catalyst is sequentially stripped and regenerated by coking to obtain a regenerated catalyst, which is then reduced and activated before being returned to the reactor for recycling. The reaction products are separated to obtain ethylene, propylene, difficult-to-convert components, and other products. The difficult-to-convert components undergo further reaction in a third reactor to obtain ethylene and propylene, among other chemical feedstocks. When the catalytic cracking method and system of this application are used for crude oil catalytic cracking, it not only further shortens the crude oil processing flow and improves the utilization rate of crude oil carbon atoms, but also results in high yields of chemical feedstocks and improves the thermal balance.

Description

Technical Field

[0001] This application relates to the petrochemical field, and more specifically, to a method and system for producing chemical feedstocks by direct catalytic cracking of crude oil with improved thermal balance. Background Technology

[0002] Ethylene, propylene, and BTX (benzene-toluene-xylene) are essential basic organic chemical raw materials, used to produce a variety of organic chemical products, including many important high-end organic chemicals, which are closely related to people's daily lives. Existing technologies for producing propylene and BTX from petroleum are developed based on traditional petroleum refining processes primarily focused on oil production. These processes suffer from problems such as long production lines, low chemical yields, and insignificant economic benefits. The key to solving these problems is to develop critical core technologies that enable the targeted conversion of crude oil hydrocarbon molecules into chemicals. Therefore, in recent years, domestic and international petrochemical companies have been actively exploring technologies for the direct production of chemicals from crude oil, thereby shortening the processing path from crude oil to low-carbon olefins and BTX, reducing energy consumption, and minimizing investment.

[0003] WO2005113722A3 and CN200780047937.2 disclose a process method for crude oil direct chemicals, in which crude oil is directly fed into a steam cracking furnace, and light components and heavy components are separated by flash evaporation. The light components (gaseous components) are fed into the steam cracking furnace for cracking, while the heavy components (liquid components) are used as feedstock for the refinery.

[0004] CN 201380015214.X discloses a process for producing olefins and aromatics from crude oil that integrates hydrotreating, steam cracking, and catalytic cracking. After hydrotreating, impurities such as sulfur and high-boiling-point substances are removed from the crude oil. The hydrotreating products are then separated by distillation; the lighter components enter a steam cracking unit, while the heavier components undergo catalytic cracking to maximize olefin production.

[0005] CN201780078199.1 discloses a method and system for converting crude oil into petrochemicals and fuel products by integrating steam cracking and fluid catalytic cracking. The crude oil is separated into straight-run naphtha and lighter fractions, one or more middle distillate fractions, and atmospheric residue. Vacuum distillate is then separated from the atmospheric residue fraction and used as feedstock for catalytic cracking. The lighter fraction is hydrogenated to produce naphtha and diesel fuel oil.

[0006] The aforementioned crude oil processing routes all primarily utilize steam cracking to produce low-carbon olefins. However, steam cracking technology suffers from high energy consumption and limited product flexibility. Researchers are actively developing technologies for producing low-carbon olefins using catalytic cracking.

[0007] CN20181189551.1 and CN201811190135.3 disclose methods for producing low-carbon olefins and aromatics through catalytic cracking of crude oil. These methods include desalting and dehydrating the crude oil, separating it into light and heavy components. The light components (light feedstock) and the heavy components (heavy feedstock) are reacted with a high-temperature catalyst in two separate catalytic cracking reactors under a steam atmosphere to produce low-carbon olefins and aromatics. Alternatively, the light and heavy components can react in different reaction zones within the same reactor.

[0008] CN 201810523356.1 discloses a method for processing crude oil full fractions. The method separates crude oil full fractions to obtain light distillate oil, medium distillate oil and heavy distillate oil. The medium and heavy distillate oils are reacted in a first riser, and the light distillate oil is reacted in a fluidized bed reactor connected in series with the riser. The reaction conditions in the reactor vary depending on the properties of the feedstock.

[0009] Existing crude oil catalytic cracking technologies all employ crude oil distillation for fraction separation, which still does not avoid the crude oil flash evaporation process and has failed to achieve a true direct catalytic cracking technology route for crude oil. Summary of the Invention

[0010] The purpose of this application is to provide a method and system for producing chemical feedstocks by direct catalytic cracking of crude oil, based on current catalytic cracking technology, which can improve the thermal balance. This method can increase the yield and selectivity of producing chemical feedstocks such as ethylene and propylene by catalytic cracking of crude oil, while also solving the potential problem of insufficient heat in the catalytic cracking reaction of crude oil.

[0011] A first aspect of the present invention provides a method for improving the thermal balance of direct catalytic cracking of crude oil, comprising:

[0012] (1) The first raw material and the first reduction and regeneration catalyst from the catalyst reducer are sequentially fed into the first reactor and the second reactor to undergo catalytic cracking reaction;

[0013] (2) The second reduction regeneration catalyst and the fresh catalyst from the catalyst reducer are respectively injected into the pre-lifting section at the bottom of the third reactor. Under the action of the pre-lifting medium, they move from bottom to top. The second raw material enters the third reactor through the feed section of the third reactor, mixes with the existing material in the reactor and undergoes a cracking reaction. The reaction oil mixture enters the second reactor to continue to undergo a cracking reaction.

[0014] (3) The reaction products and the catalyst to be generated in the second reactor are fed into the oil-solid separation equipment for gas-solid separation. The separated reaction oil and gas are taken out of the device for further separation to obtain ethylene, propylene, difficult-to-convert components and other products.

[0015] (4) The separated catalyst enters the regenerator for carbonization regeneration, and the regenerated catalyst is sent to the reducer.

[0016] (5) The regenerated catalyst comes into contact with the reducing agent in the reducer to undergo a reduction reaction and release energy to obtain the reduced regenerated catalyst. The first part of the reduced regenerated catalyst is returned to the first reactor for recycling, and the second part of the reduced regenerated catalyst is returned to the third reactor for reaction use.

[0017] The first raw material is selected from one or more of paraffin-based crude oil, paraffin-intermediate-based crude oil, and intermediate-paraffin oil crude oil.

[0018] The second feedstock is self-produced by the unit and / or other difficult-to-convert components. The difficult-to-convert components are light hydrocarbons and / or light distillate oils with a final boiling point of less than 280-360°C. The light hydrocarbons are preferably C4 fractions, and the C4 fractions contain more than 50% by weight of C4 olefins.

[0019] According to the method described in the first aspect, the catalytic cracking reaction conditions in the first reactor are as follows:

[0020] The reaction temperature is 550-650℃;

[0021] The reaction time is 0.1-5 seconds; and / or

[0022] The weight ratio of the agent to the oil is (5-30):1;

[0023] Preferably, the first raw material is preheated and steam atomized before entering the first reactor. The preheating temperature is 180-350℃ and the water-oil weight ratio is (0.05-0.5):1.

[0024] According to the method described in the first aspect, the catalytic cracking reaction conditions in the second reactor are as follows:

[0025] The reaction temperature is 450-600℃; and / or

[0026] Heavy hourly space velocity is 1-20 hours -1 .

[0027] According to the method described in the first aspect, the catalytic cracking reaction conditions in the third reactor are as follows:

[0028] The reaction temperature is 600-720℃;

[0029] The reaction time is 0.1-3 seconds; and / or

[0030] The weight ratio of the agent to the oil is (5-50):1;

[0031] Preferably, the second raw material is introduced into the third reactor after being atomized by steam, and the water-to-oil weight ratio is (0.05-0.5):1.

[0032] According to the method described in the first aspect, the weight ratio of fresh catalyst injected into the third reactor to regenerated catalyst is 0.005-0.3:1.

[0033] According to the method described in the first aspect, the third reactor is provided with a main reaction section and one or more second raw material feeding sections;

[0034] Preferably, the one or more second raw material feed sections are each independently located in the middle to upstream of the third reactor; and / or

[0035] Preferably, the catalyst density in each of the second raw material feed sections is 120-290 kg / m³. 3 .

[0036] According to the method described in the first aspect, the reduction temperature in the catalyst reducer is 550-700℃ and / or the reduction time is 2-20 minutes.

[0037] According to the method of the first aspect, the catalyst comprises 0.01-5% by weight, preferably 0.005-3% by weight, of a metal oxide, based on the dry weight of the catalyst, wherein the metal oxide is selected from one or more of the following: tin, cobalt, iron, molybdenum, manganese, copper, barium, and chromium.

[0038] Preferably, the catalyst comprises:

[0039] 0-70 parts by weight, preferably 5-60 parts by weight, more preferably 10-50 parts by weight of clay,

[0040] 5-99 parts by weight, preferably 10-80 parts by weight, more preferably 20-70 parts by weight of adhesive,

[0041] 1-60 parts by weight, preferably 5-45 parts by weight, more preferably 10-40 parts by weight of zeolite, and

[0042] 0.001-5 parts by weight, preferably 0.005-2 parts by weight, of a metal oxide.

[0043] And the total weight of the catalyst is 100 parts by weight;

[0044] The adhesive is an inorganic oxide adhesive, preferably silicon dioxide and / or aluminum oxide;

[0045] The zeolite includes mesoporous zeolite and optional macroporous zeolite. The mesoporous zeolite is ZSM series zeolite and / or ZRP zeolite. The macroporous zeolite is selected from one or more of rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite and high silica Y-type zeolite. Preferably, the mesoporous zeolite accounts for 5-100% of the total weight of the zeolite, more preferably 50-90% by weight, and more preferably 20-50% by weight.

[0046] The clay is preferably kaolin and / or hydrous kaolin.

[0047] A second aspect of the present invention provides a catalytic cracking system, comprising:

[0048] The catalytic cracking reaction unit includes:

[0049] The first reactor is provided with a pre-lifting medium inlet, a first reduction and regeneration catalyst inlet, a first raw material inlet, and a first oil agent outlet from bottom to top.

[0050] The second reactor is provided with a first oil mixture inlet and a third oil mixture inlet, and the first oil outlet of the first reactor extends into the second reactor through the first oil mixture inlet of the second reactor;

[0051] The third reactor, arranged from bottom to top, includes a pre-lifting section, a feed section, a main reaction section, and an outlet section. The bottom of the pre-lifting section has a second reduction regeneration catalyst inlet, a fresh catalyst inlet, and a pre-lifting medium inlet. The feed section has a difficult-to-convert feedstock inlet, a circulating catalyst inlet, and an optional catalyst outlet. The outlet section of the third reactor extends into the second reactor through the third oil-agent mixture inlet of the second reactor.

[0052] An oil-solvent separation device is provided with an oil inlet, a catalyst outlet, and a reaction product outlet. The oil inlet of the oil-solvent separation device is connected to a second reactor, so that the oil-solvent mixture from the second reactor is separated into reaction oil gas and catalyst to be generated by the oil-solvent separation device.

[0053] A settling device is provided inside the second reactor for settling and collecting the catalyst to be generated after being separated by the oil-agent separation device. A stripping section is provided below the settling device for stripping the catalyst to be generated. The stripping section is provided with a catalyst outlet and a stripping medium inlet.

[0054] A reaction product separation unit, which is connected to an oil separation device, is used to separate the reaction oil and gas separated by the oil separation device.

[0055] The regenerator includes a catalyst inlet, an oxygen-containing gas inlet, a gas distributor, a cyclone separator, a regenerated flue gas pipeline, and a regenerated catalyst outlet; the catalyst inlet of the regenerator is in fluid communication with the catalyst outlet of the stripping section; and

[0056] A catalyst reducer is provided with a reduction medium inlet, a regeneration catalyst inlet, and at least one reduction-regeneration catalyst outlet. The regeneration catalyst inlet of the catalyst reducer is connected to the regeneration catalyst outlet of the regeneration catalyst, so that the regeneration catalyst from the regeneration catalyst is reduced within the catalyst reducer. One reduction-regeneration catalyst outlet of the catalyst reducer is in fluid communication with a first reduction-regeneration catalyst inlet of a first reactor, so that a portion of the reduction-regeneration catalyst is recycled back to the first reactor. One reduction-regeneration catalyst outlet of the catalyst reducer is in fluid communication with a second reduction-regeneration catalyst inlet of a third reactor, so that a portion of the reduction-regeneration catalyst is recycled back to the third reactor.

[0057] According to the system described in the second aspect, the feed section of the third reactor includes a first feed section and a second feed section, and an external catalyst circulation pipeline connecting the first feed section and the second feed section is provided between the first feed section and the second feed section.

[0058] Preferably, the diameter ratio of the first feed section and the second feed section of the third reactor to the main reaction section is independently 1.2-1.5:1.

[0059] According to the system described in the second aspect, the third reactor includes two feed sections connected in sequence, the first feed section is connected to the pre-lifting section, the second feed section is connected to the main reaction section, and an external catalyst circulation pipeline connecting the two feed sections is provided between the first feed section and the second feed section.

[0060] Preferably, the distance from the connection port of the external catalyst circulation pipe on the first feed section to the bottom of the first feed section is 0 to 10% of the height of the second feed section; and / or the distance from the outlet of the catalyst on the second feed section to the bottom of the second feed section is 5% to 20% of the height of the second feed section.

[0061] Compared with the prior art, the method and system of the present invention have the following advantages:

[0062] 1) It can realize direct catalytic cracking of crude oil, reduce the crude oil distillation process, and has a simple process and low operating costs.

[0063] 2) In the process of crude oil catalytic cracking, the single-pass conversion rate is not pursued. The light distillate oil that is difficult to convert is recycled. By setting up a specific reaction zone, a higher total conversion rate and a higher selectivity of target products can be achieved.

[0064] 3) Based on the reactivity of the difficult-to-convert components, they are introduced into the reactor in a specific feed section of the third reactor. The higher catalyst density and higher catalyst activity in the feed section are beneficial to improving the reaction conversion rate and catalytic selectivity of the difficult-to-convert components.

[0065] 4) The catalyst in the second feed section can be selectively returned to the first feed section to increase the catalyst-to-oil ratio in the first feed section, or it can be selectively removed from the reactor according to the degree of carbonization of the catalyst, which helps to improve the catalyst activity in the reactor.

[0066] 5) The catalyst contains a metal with a variable valence state, which stores and releases energy through the gain or loss of electrons between the metal and the metal oxide or the shift of shared electron pairs, thus providing heat for the reaction and solving or improving the problem of insufficient heat balance during the reaction process.

[0067] The catalytic cracking method of this application can directly and efficiently produce chemical feedstocks such as ethylene and propylene from crude oil. This not only further shortens the crude oil processing flow and helps refineries transform, develop, and extend from oil refining to chemical feedstock production, but also improves the economic benefits of refineries. Attached Figure Description

[0068] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the following detailed description to explain the present application, but do not constitute a limitation thereof. In the drawings:

[0069] Figure 1 A schematic diagram of a process for producing chemical feedstocks from crude oil by direct catalytic cracking, as provided in this application.

[0070] Explanation of reference numerals in the attached figures:

[0071] 100. First reactor; 101. First pre-lifting medium pipeline; 102. First feed pipeline; 104. First reactor outlet; 200. Settler; 201. Stripping section; 202. Stripping medium; 203. Preparing inclined tube; 204. Oil-catalyst separator; 205. Gas collecting chamber; 206. Main oil-gas pipeline; 207. Second reactor; 300. Third reactor; 301. Second pre-lifting medium pipeline; 302. Fresh catalyst pipeline; 303. Second feed pipeline; 304. Third feed pipeline; 305. Fourth feed pipeline; 306. 307. Catalyst circulation pipe; 308. Catalyst outlet pipe; 309. Third reactor outlet section; 310. Third reactor pre-lift section; 311. Third reactor main reaction section; 312. Third reactor first feed section; 313. Third reactor second feed section; 400. Regenerator; 401. Oxygen-containing gas inlet; 402. Main air distributor; 403. Regenerated catalyst outlet; 404. Cyclone separator; 405. Regenerated flue gas pipeline; 500. Reducer; 501. Reduction medium inlet; 502. Second regeneration inclined pipe; 503. First regeneration inclined pipe. Detailed Implementation

[0072] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0073] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0074] Any specific numerical value (including the endpoints of a numerical range) disclosed in this application is not limited to the exact value, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, with respect to the disclosed numerical range, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0075] In this application, the terms "upstream" and "downstream" refer to the direction of reaction material flow. For example, when the reaction material flows from bottom to top, "upstream" refers to the position located at the bottom, while "downstream" refers to the position located at the top.

[0076] In this article, low carbon olefins are a collective term for ethylene, propylene, and butene, and light aromatic hydrocarbons (BTX) are a collective term for benzene (BTX), toluene (T), and xylene (X).

[0077] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0078] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0079] This invention provides a method for improving the thermal balance of direct catalytic cracking of crude oil, comprising:

[0080] (1) The first raw material and the first reduction and regeneration catalyst from the catalyst reducer are sequentially fed into the first reactor and the second reactor to undergo catalytic cracking reaction;

[0081] (2) The second reduction regeneration catalyst and the fresh catalyst from the catalyst reducer are respectively injected into the pre-lifting section at the bottom of the third reactor. Under the action of the pre-lifting medium, they move from bottom to top. The second raw material enters the third reactor through the feed section of the third reactor, mixes with the existing material in the reactor and undergoes a cracking reaction. The reaction oil mixture enters the second reactor to continue to undergo a cracking reaction.

[0082] (3) The reaction products and the catalyst to be generated in the second reactor are fed into the oil-solid separation equipment for gas-solid separation. The separated reaction oil and gas are taken out of the device for further separation to obtain ethylene, propylene, difficult-to-convert components and other products.

[0083] (4) The separated catalyst enters the regenerator for carbonization regeneration, and the regenerated catalyst is sent to the reducer.

[0084] (5) The regenerated catalyst comes into contact with the reducing agent in the reducer to undergo a reduction reaction and release energy to obtain the reduced regenerated catalyst. The first part of the reduced regenerated catalyst is returned to the first reactor for recycling, and the second part of the reduced regenerated catalyst is returned to the third reactor for reaction use.

[0085] The first raw material is selected from one or more of paraffin-based crude oil, paraffin-intermediate-based crude oil, and intermediate-paraffin oil crude oil.

[0086] The second feedstock is self-produced by the unit and / or other difficult-to-convert components. The difficult-to-convert components are light hydrocarbons and / or light distillate oils with a final boiling point of less than 280-360°C. The light hydrocarbons are preferably C4 fractions, and the C4 fractions contain more than 50% by weight of C4 olefins.

[0087] The present application will be further described below with reference to the preferred embodiments shown in the accompanying drawings, but this does not limit the present application.

[0088] Figure 1A preferred embodiment of the catalytic cracking method of this application is provided, wherein the catalytic cracking reactor includes a first reactor 100, a second reactor 207, and a third reactor 300. The third reactor 300 is provided with a pre-lifting section 309, a first feed section 311, a second feed section 312, a main reaction section 310, and an outlet section 308.

[0089] The pre-lifting medium enters the bottom of the first reactor 100 via the first pre-lifting medium pipeline 101. The lifting medium can be dry gas, water vapor, or a mixture thereof. The reduced regenerated catalyst from the first regeneration inclined tube 503 enters the bottom of the first reactor 100, moving upwards and mixing under the lifting action of the pre-lifting medium. Reactant feedstocks, such as preheated crude oil and atomized steam, are injected into the bottom of the first reactor 100 via the first feed pipeline 102, mixing and contacting with the existing oil gas and catalyst in the catalytic cracking reactor. Catalytic cracking occurs as the reactants pass through the first reactor 100 from bottom to top. The reactant oil gas and catalyst flow upwards through the first reactor outlet 104 into the second reactor 207, where the catalytic cracking reaction continues. The catalyst containing coke generated from the reaction and the reaction oil and gas enter the oil-solid separation device 204, such as a cyclone separator, for gas-solid separation. The separated reaction oil and gas are led out through the gas collection chamber 205 and the large oil and gas pipe 206 and enter the subsequent separation system. The separated coke-containing recycled catalyst enters the lower part of the settling tank 200 and enters the regenerator 400 through the recycled inclined pipe 203.

[0090] The pre-lifting medium enters the bottom of the third reactor 300 via the second pre-lifting medium line 301. The lifting medium can be dry gas, water vapor, or a mixture thereof. The reduced regenerated catalyst from the first regeneration inclined tube 503 enters the bottom of the third reactor 300, mixes with the fresh catalyst from the fresh catalyst line 302, and moves upward.

[0091] Some of the difficult-to-convert raw materials and atomized steam are injected into the lower part of the first feed section 311 of the third reactor through the second feed line 303, where they mix and come into contact with the existing catalyst in the catalytic cracking reactor. The oil-agent mixture moves upward and mixes with the part of difficult-to-convert raw materials injected through the third feed line 304, entering the bottom of the second feed section 312. Optionally, some of the difficult-to-convert raw materials enter the upper part of the second feed section through the pipeline 305, and the oil-agent mixture enters the main reaction section 310, where a full cracking reaction occurs. The reaction products enter the second reactor 207 through the outlet section.

[0092] The catalyst-to-oil ratio and activity of the catalyst in the first feed section 311 and the second feed section 312 can be adjusted according to the reaction requirements by regulating the flow rate of the external catalyst circulation pipeline 306 and the catalyst outlet pipeline 307.

[0093] The catalyst containing coke enters the regenerator 400, where it comes into contact with oxygen-containing gas injected through the oxygen-containing gas inlet 401 and the main air distributor 402 and undergoes a complete combustion reaction, releasing heat completely. The regenerated catalyst is then sent to the reducer through the regenerated catalyst outlet 403.

[0094] The regenerated catalyst comes into contact with the reducing medium injected from the bottom of the reducer 500 through the reducing medium inlet 501 in the reducer 500. The metal oxides in the catalyst are activated. Part of the reduced regenerated catalyst is recycled to the first reactor through the first regeneration inclined tube 503, and part of the regenerated catalyst is recycled to the third reactor through the second regeneration inclined tube 502. The regenerated flue gas is separated from the entrained catalyst by the cyclone separator 404 and then enters the energy recovery system through the regenerated flue gas pipeline 405.

[0095] The catalytic cracking method provided in this application is applicable to crude oils selected from paraffinic crude oils, paraffinic-intermediate crude oils, and intermediate-paraffinic crude oils. In the paraffinic crude oil, either the first critical component or the second critical group is paraffinic; in the paraffinic-intermediate crude oil, the first critical component is paraffinic and the second critical group is intermediate; in the intermediate-paraffinic crude oil, the first critical component is intermediate and the second critical group is paraffinic.

[0096] In one embodiment, the crude oil has a characteristic factor K value of not less than 12.0 and a relative density of 780-900 kg / m³. 3 .

[0097] In this application, the difficult-to-convert component is one or a mixture of light hydrocarbons such as C4 fractions or light distillate oils with a final boiling point of less than 280-360°C.

[0098] In one embodiment, the C4 fraction refers to low-molecular-weight hydrocarbons existing in gaseous form at room temperature and pressure, with C4 fraction as the main component, including alkanes, alkenes, and alkynes with 4 carbon atoms in their molecules. It includes gaseous hydrocarbon products rich in C4 fraction produced by the apparatus of this invention, and may also include gaseous hydrocarbons rich in C4 fraction produced by other apparatus processes, wherein the C4 fraction produced by the apparatus of this 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 most preferably greater than 70% by weight.

[0099] In one embodiment, the light distillate oil with a final boiling point less than 280-360°C includes light distillate oils of various boiling ranges with a final boiling point less than 280-360°C produced by the apparatus of the present invention, such as light gasoline and light diesel oil. It may also include one or more mixtures of primary processed straight-run naphtha, straight-run kerosene, and straight-run diesel oil; and one or more mixtures of secondary processed topping oil, residue oil, hydrocracked light naphtha, pentane oil, coking gasoline, Fischer-Tropsch synthetic oil, catalytic cracked light gasoline, hydrotreated gasoline, and hydrotreated diesel oil.

[0100] In one embodiment, the catalytic cracking reaction conditions in the first reactor are as follows:

[0101] The reaction temperature is 550-650℃;

[0102] The reaction time is 0.1-5 seconds; and / or

[0103] The weight ratio of the agent to the oil is (5-30):1;

[0104] Preferably, the first raw material is preheated and steam atomized before entering the first reactor. The preheating temperature is 180-360℃ and the water-oil weight ratio is (0.05-0.5):1.

[0105] In this application, the catalytic cracking reaction temperature of the first reactor refers to the reactor outlet temperature.

[0106] In one embodiment, the catalytic cracking reaction conditions in the second reactor are as follows:

[0107] The reaction temperature is 450-600℃;

[0108] Heavy hourly space velocity is 1-20 hours -1 ; and / or

[0109] In this application, the catalytic cracking reaction temperature of the second reactor refers to the bed temperature of the second reactor.

[0110] In one embodiment, the catalytic cracking reaction conditions in the third reactor are as follows:

[0111] The reaction temperature is 600-720℃;

[0112] The reaction time is 0.1-3 seconds; and / or

[0113] The weight ratio of the agent to the oil is (5-50):1;

[0114] Preferably, the second raw material is introduced into the third reactor after being atomized by steam, and the water-to-oil weight ratio is (0.05-0.5):1.

[0115] In this application, the catalytic cracking reaction temperature of the third reactor refers to the reactor outlet temperature.

[0116] In one embodiment, the weight ratio of fresh catalyst injected into the third reactor to reduction and regeneration catalyst is 0.005-0.3:1.

[0117] In one embodiment, the third reactor is provided with a main reaction section and one or more second raw material feed sections;

[0118] Preferably, the one or more second raw material feed sections are each independently located in the middle to upstream of the third reactor; and / or

[0119] Preferably, the catalyst density in each of the second raw material feed sections is 120-290 kg / m³. 3 .

[0120] In one embodiment, one or more of the difficult-to-convert components may be fed at at least one or more identical locations in the feed section of the third reactor, or they may be fed at different locations.

[0121] In one embodiment, the reduction temperature in the catalyst reducer is 550-700°C and / or the reduction time is 2-20 minutes.

[0122] In one embodiment, the temperature inside the regenerator is 550-750°C, more preferably 600-730°C, and even more preferably 650-700°C; the apparent linear velocity of the gas is 0.3-3 m / s, preferably 0.5-2.5 m / s, more preferably 0.6-1.5 m / s, and the average residence time of the catalyst to be generated is 0.6-8 minutes, preferably 0.8-6 minutes, and more preferably 1-5 minutes.

[0123] In one embodiment, the catalyst comprises 0.01-5 wt%, preferably 0.005-2 wt%, of a metal oxide, based on a dry weight of the catalyst, wherein the metal oxide is selected from one or more of the following: tin, cobalt, iron, molybdenum, manganese, copper, barium, and chromium.

[0124] Preferably, the catalyst comprises:

[0125] 0-70 parts by weight, preferably 5-60 parts by weight, more preferably 10-50 parts by weight of clay,

[0126] 5-99 parts by weight, preferably 10-80 parts by weight, more preferably 20-70 parts by weight of adhesive,

[0127] 1-60 parts by weight, preferably 5-45 parts by weight, more preferably 10-40 parts by weight of zeolite, and

[0128] 0.001-5 parts by weight, preferably 0.005-2 parts by weight, of a metal oxide.

[0129] And the total weight of the catalyst is 100 parts by weight;

[0130] The adhesive is an inorganic oxide adhesive, preferably silicon dioxide and / or aluminum oxide;

[0131] The zeolite includes mesoporous zeolite and optional macroporous zeolite. The mesoporous zeolite is ZSM series zeolite and / or ZRP zeolite. The macroporous zeolite is selected from one or more of rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite and high silica Y-type zeolite. Preferably, the mesoporous zeolite accounts for 5-100% of the total weight of the zeolite, more preferably 50-90% by weight, and more preferably 20-50% by weight.

[0132] The clay is preferably kaolin and / or hydrous kaolin.

[0133] In the catalyst used in this invention, clay is used as the catalyst matrix (i.e., support), and inorganic oxides are used as binders.

[0134] In this application, mesoporous zeolite and macroporous zeolite are defined according to conventional definitions in the art, namely, the average pore size of mesoporous zeolite is about 0.5-0.6 nm, and the average pore size of macroporous zeolite is about 0.7-1.0 nm.

[0135] As an example, the macroporous zeolite may 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-silica Y type zeolite. The mesoporous zeolite may be selected from zeolites with an MFI structure, such as ZSM series zeolites and / or ZRP zeolite. Optionally, the above-mentioned mesoporous zeolites may 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 US Patent 5,232,675A. The 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 with similar structures. A more detailed description of ZSM-5 can be found in US Patent 3,702,886A.

[0136] The catalyst of this invention contains a metal with a variable valence state. It stores and releases energy through the gain or loss of electrons between the metal and the metal oxide or the shift of shared electron pairs, thereby providing heat for the catalytic cracking reaction of difficult-to-convert components and solving the problem of high reaction heat demand of difficult-to-convert components.

[0137] This invention incorporates a catalyst reducer in the reaction system. The catalyst portion regenerated by the regenerator enters the reducer and mixes with the fresh catalyst. Under the action of a reducing medium (e.g., refinery dry gas and / or small molecule alkanes), the variable valence metal oxides in the mixed catalyst are reduced and release energy. The reduced and regenerated catalyst carries the energy into the second reactor to participate in the reaction, thereby providing heat for the catalytic cracking reaction of the difficult-to-convert components in the second reactor, solving the problem of high reaction heat demand for the difficult-to-convert components in the second reactor.

[0138] In the method provided by this invention, the catalyst preparation method adopts a conventional method for preparing catalytic cracking catalysts, which is well known to those skilled in the art. The metal loaded onto the catalyst can be achieved by impregnation or slurry mixing, with impregnation being preferred; these methods are well known to those skilled in the art.

[0139] According to this application, the separation of reaction products from the catalyst to be generated is well known to those skilled in the art. For example, it can be carried out in a settling tank using a cyclone separator. The method of further separating the reaction oil and gas to obtain dry gas, liquefied gas, light distillate oil from difficult-to-convert components, and cracked heavy oil is also well known to those skilled in the art. The dry gas and liquefied gas can be further separated using conventional separation methods in the art to obtain target products such as ethylene and propylene, as well as C4 fractions.

[0140] The present invention also provides a catalytic cracking system, comprising:

[0141] The catalytic cracking reaction unit includes:

[0142] The first reactor is provided with a pre-lifting medium inlet, a first reduction and regeneration catalyst inlet, a first raw material inlet, and a first oil agent outlet from bottom to top.

[0143] The second reactor is provided with a first oil mixture inlet and a third oil mixture inlet, and the first oil outlet of the first reactor extends into the second reactor through the first oil mixture inlet of the second reactor;

[0144] The third reactor, arranged from bottom to top, includes a pre-lifting section, a feed section, a main reaction section, and an outlet section. The bottom of the pre-lifting section has a second reduction regeneration catalyst inlet, a fresh catalyst inlet, and a pre-lifting medium inlet. The feed section has a difficult-to-convert feedstock inlet, a circulating catalyst inlet, and an optional catalyst outlet. The outlet section of the third reactor extends into the second reactor through the third oil-agent mixture inlet of the second reactor.

[0145] An oil-solvent separation device is provided with an oil inlet, a catalyst outlet, and a reaction product outlet. The oil inlet of the oil-solvent separation device is connected to a second reactor, so that the oil-solvent mixture from the second reactor is separated into reaction oil gas and catalyst to be generated by the oil-solvent separation device.

[0146] A settling device is provided inside the second reactor for settling and collecting the catalyst to be generated after being separated by the oil-agent separation device. A stripping section is provided below the settling device for stripping the catalyst to be generated. The stripping section is provided with a catalyst outlet and a stripping medium inlet.

[0147] A reaction product separation unit, which is connected to an oil separation device, is used to separate the reaction oil and gas separated by the oil separation device.

[0148] The regenerator includes a catalyst inlet, an oxygen-containing gas inlet, a gas distributor, a cyclone separator, a regenerated flue gas pipeline, and a regenerated catalyst outlet; the catalyst inlet of the regenerator is in fluid communication with the catalyst outlet of the stripping section; and

[0149] A catalyst reducer is provided with a reduction medium inlet, a regeneration catalyst inlet, and at least one reduction-regeneration catalyst outlet. The regeneration catalyst inlet of the catalyst reducer is connected to the regeneration catalyst outlet of the regeneration catalyst, so that the regeneration catalyst from the regeneration catalyst is reduced within the catalyst reducer. One reduction-regeneration catalyst outlet of the catalyst reducer is in fluid communication with a first reduction-regeneration catalyst inlet of a first reactor, so that a portion of the reduction-regeneration catalyst is recycled back to the first reactor. One reduction-regeneration catalyst outlet of the catalyst reducer is in fluid communication with a second reduction-regeneration catalyst inlet of a third reactor, so that a portion of the reduction-regeneration catalyst is recycled back to the third reactor.

[0150] In one embodiment, the feed section of the third reactor includes a first feed section and a second feed section, and an external catalyst circulation pipeline connecting the first feed section and the second feed section is provided between the first feed section and the second feed section.

[0151] Preferably, the diameter ratio of the first feed section and the second feed section of the third reactor to the main reaction section is independently 1.2-1.5:1.

[0152] In one embodiment, the third reactor includes two feed sections connected in sequence. The first feed section is connected to the pre-lifting section, and the second feed section is connected to the main reaction section. An external catalyst circulation pipeline connecting the two feed sections is provided between the first feed section and the second feed section.

[0153] Preferably, the distance from the connection port of the external catalyst circulation pipe on the first feed section to the bottom of the first feed section is 0 to 10% of the height of the second feed section; and / or the distance from the outlet of the catalyst on the second feed section to the bottom of the second feed section is 5% to 20% of the height of the second feed section.

[0154] The height of the second feeding section is H1 as shown in the figure.

[0155] In this application, a catalyst distribution plate can be installed at the bottom of the catalyst inlet of the regenerator, for example, at the outlet end of the auxiliary regenerator. According to this application, the catalyst distribution plate can be one or more of various types commonly used in industry, such as flat, arched, disc-shaped, annular, and umbrella-shaped plates. Using a catalyst distribution plate helps to ensure uniform concentration of the catalyst in contact with the oxygen-enriched gas along the axial direction of the regenerator for the coking reaction, improving coking efficiency and reducing the occurrence of localized hot spots in the catalyst bed.

[0156] According to this application, the oil separation equipment and the reaction product separation equipment are well known to those skilled in the art. For example, the oil separation equipment may include a cyclone separator, a settling tank, and a stripper, while the reaction product separation equipment may be a distillation tower, etc.

[0157] Example

[0158] The following embodiments will further illustrate this application, but do not limit this application.

[0159] The feedstock used in the following examples and comparative examples was crude oil from the Subei Oilfield of Jiangsu Province, and its properties are shown in Table 1. The comparative catalyst used was a commercial catalytic cracking catalyst purchased from the Catalyst Division of China Petroleum & Chemical Corporation, with the trade name DMMC-1. The catalyst used in the examples was DMMC-1 catalyst containing CuO, and the amount of CuO was 1.0 wt% of the total catalyst weight.

[0160] Example 1

[0161] Using the feedstock oils shown in Table 1 and the CuO-containing DMMC-1 catalyst, in Figure 1 The experiment was conducted on the medium-sized apparatus shown, in which the reactor structure is as follows:

[0162] The conventional riser reactor (first reactor) is connected in series with the fluidized bed reactor (second reactor) with a total height of 7 meters. The third reactor has a height of 5 meters and an inner diameter of 0.2 meters. There are two feed sections at the bottom, each with a height of 0.2 meters and an inner diameter of 0.3 meters. The first feed section has one feed inlet and the second feed section has two feed inlets.

[0163] The reduced, hot-regenerated catalyst from the first regeneration inclined tube 503 enters the lower part of the first reactor, contacts the existing oil-agent mixture in the reactor, and moves upward. Preheated crude oil and atomized steam are injected into the first reactor through the first feed line 102, with a water-to-oil weight ratio of 0.2:1, and mix with the existing catalyst in the catalytic cracking reactor. During the process of passing through the first and second reactors from bottom to top, a catalytic cracking reaction is carried out. The resulting catalyst with coke and the reaction oil and gas enter the oil-agent separation device 204, such as a cyclone separator, for gas-solid separation. The separated reaction oil and gas are led out through the gas collection chamber 205 and the large oil and gas pipe 206 to enter the subsequent separation system. The separated catalyst with coke enters the lower part of the settling tank 200 and enters the regenerator 400 through the regeneration inclined tube 203.

[0164] The hot-regenerated catalyst from the second regeneration inclined tube 502 and the fresh catalyst from the first feed line 102 enter the third reactor III. Under the lifting action of the pre-lifting medium injected through the first pre-lifting medium line 101, they move upward. The C4 fraction and light distillate oil from the separation system enter the lower part of the first feed section through the second feed line 303. The water-oil weight ratio is 0.2:1. They come into contact with the mixed catalyst and move upward. They undergo a full reaction in the main reaction section. The reaction products and catalyst enter the second reactor through the outlet section.

[0165] The catalyst containing coke enters the regenerator and undergoes a complete combustion reaction upon contact with air. The regenerated catalyst then enters the reducer and undergoes a reduction and activation reaction upon contact with dry gas. The regenerated catalyst after reduction is divided into two parts: one part is returned to the first reactor for recycling via the first regeneration inclined tube 503, and the other part is returned to the third reactor for recycling via the second regeneration inclined tube 502. The regenerated flue gas enters the energy recovery system via the regenerated flue gas pipeline 405.

[0166] Operating conditions and product distribution are listed in Tables 2 and 3. As can be seen from Table 2, the ethylene yield in this embodiment reached 7.55% by weight, the propylene yield reached 24.52% by weight, and the total yield of ethylene, propylene, and light aromatics reached 42.44%.

[0167] Example 2

[0168] Using the feedstock oils shown in Table 1 and the CuO-containing DMMC-2 catalyst, in Figure 1 The experiment was conducted on the medium-sized apparatus shown, wherein the reactor used had the same structure as in Example 1.

[0169] The reduced, hot-regenerated catalyst from the first regeneration inclined tube 503 enters the lower part of the first reactor, contacts the existing oil-agent mixture in the reactor, and moves upward. Preheated crude oil and atomized steam are injected into the first reactor through the first feed line 102, with a water-to-oil weight ratio of 0.2:1. They mix and contact with the existing catalyst in the catalytic cracking reactor, and undergo catalytic cracking reaction as they pass from bottom to top through the first and second reactors. The resulting catalyst with coke and the reaction oil and gas enter the oil-agent separation device 204, such as a cyclone separator, for gas-solid separation. The separated reaction oil and gas are led out through the gas collecting chamber 205 and the large oil and gas pipe 206 to enter the subsequent separation system. The separated catalyst with coke enters the lower part of the settling tank 200 and enters the regenerator 400 through the regeneration inclined tube 203.

[0170] The hot-regenerated catalyst from the second regeneration inclined tube 502 and the fresh catalyst from the first feed line 102 enter the third reactor III. Under the lifting action of the pre-lifting medium injected through the first pre-lifting medium line 101, they move upward. The C4 fraction from the separation system enters the lower part of the first feed section through the second feed line 303, and the light distillate oil enters the lower part of the second feed section through the third feed line 304. The water-oil weight ratio is 0.2:1, which contacts the mixed catalyst and moves upward. The reaction is carried out fully in the main reaction section, and the reaction products and catalyst enter the second reactor through the outlet section.

[0171] The catalyst containing coke enters the regenerator and undergoes a complete combustion reaction upon contact with air. The regenerated catalyst then enters the reducer and undergoes a reduction and activation reaction upon contact with dry gas. The regenerated catalyst after reduction is divided into two parts: one part is returned to the first reactor for recycling via the first regeneration inclined tube 503, and the other part is returned to the third reactor for recycling via the second regeneration inclined tube 502. The regenerated flue gas enters the energy recovery system via the regenerated flue gas pipeline 405.

[0172] Operating conditions and product distribution are listed in Tables 2 and 3. As can be seen from Table 2, the ethylene yield in this embodiment reached 8.77% by weight, the propylene yield reached 26.51% by weight, and the total yield of ethylene, propylene, and light aromatics reached 44.84%.

[0173] Comparative Example 1

[0174] Using the feedstock and DMMC-1 catalyst shown in Table 1, experiments were conducted on a medium-sized unit. The reactor consisted of a conventional riser reactor (first reactor), a fluidized bed reactor (second reactor) connected in series, and a third reactor connected to the second reactor. Preheated feedstock sequentially entered the riser reaction zone and the fluidized bed reactor to react with the catalytic cracking catalyst. The post-reaction stream entered subsequent oil-catalyst separation and product separation equipment. The separated C4 fraction and light gasoline were returned to the bottom of the third reactor to react with the regenerated catalyst. The resulting oil-catalyst mixture entered the second reactor. The separated regenerated catalyst entered the lower part of the regenerator, where it reacted with air distributed into the regenerator via the main air distributor, resulting in a coking reaction. Fuel oil was injected into the dense phase catalyst bed, where it reacted with the high-temperature air, releasing heat. The regenerated catalyst was returned to the reactor for recycling. Operating conditions and product distribution are listed in Tables 2 and 3.

[0175] As can be seen from the results in Table 2, the ethylene yield in this comparative example is only 5.72% by weight, the propylene yield is only 21.22% by weight, and the total yield of ethylene, propylene, and light aromatics is 37.29%.

[0176] The results from the above examples and comparative examples show that when using the catalytic cracking method and system of this application for crude oil catalytic cracking reaction, the crude oil atom utilization rate is high, and the yield of chemical feedstocks such as ethylene and propylene is significantly improved. The temperature field distribution inside the reactor is significantly improved, alleviating the heat balance problem to a certain extent.

[0177] The preferred embodiments of this application have been described in detail above. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0178] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0179] Furthermore, various different embodiments of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content of this application.

[0180] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0181] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

[0182] Properties of the crude oil used (Table 1)

[0183]

[0184] Table 2 Comparison of reaction conditions between the examples and comparative examples

[0185]

[0186]

[0187] Table 3 Comparison of reaction results between the examples and comparative examples

[0188] Comparative Example 1 Example 1 Example 2 Product distribution, weight % gas 51.32 50.97 56.74 ethylene 5.72 7.55 8.77 Among them, propylene 21.22 24.52 26.51 gasoline 23.34 23.59 21.56 coke 8.08 8.28 8.70 total 100.00 100.00 100.00 Ethylene + Propylene + BTX 37.29 42.44 44.84 Low-carbon olefins + light aromatics 51.84 49.39 52.74

Claims

1. A method for direct catalytic cracking of crude oil with improved thermal balance, comprising: (1) The first raw material and the first reduction regeneration catalyst from the catalyst reducer enter the first reactor and the second reactor in sequence to undergo catalytic cracking reaction; (2) The second reduction regeneration catalyst and the fresh catalyst from the catalyst reducer are respectively injected into the pre-lifting section at the bottom of the third reactor. Under the action of the pre-lifting medium, they move from bottom to top. The second raw material enters the third reactor through the feed section of the third reactor, mixes with the existing material in the reactor and undergoes a cracking reaction. The reaction oil mixture enters the second reactor to continue to undergo a cracking reaction. (3) The reaction products and the catalyst to be generated in the second reactor are fed into the oil-solid separation equipment for gas-solid separation. The separated reaction oil and gas are led out of the device for further separation to obtain ethylene, propylene, difficult-to-convert components and other products. (4) The separated catalyst enters the regenerator for carbonization reaction regeneration, and the regenerated catalyst is sent to the reducer; (5) The regenerated catalyst comes into contact with the reducing agent in the reducer to undergo a reduction reaction and release energy to obtain a reduced regenerated catalyst. The first part of the reduced regenerated catalyst is returned to the first reactor for recycling, and the second part of the reduced regenerated catalyst is returned to the third reactor for use in the reaction. The first raw material is selected from one or more of paraffin-based crude oil, paraffin-intermediate-based crude oil, and intermediate-paraffin oil crude oil. The second feedstock is self-produced by the unit and / or other difficult-to-convert components, wherein the difficult-to-convert components are light hydrocarbons and / or light distillate oils with a final boiling point of less than 280-360°C; Based on the dry weight of the catalyst, the catalyst comprises 0.001-5% by weight of a metal oxide, wherein the metal oxide is selected from one or more of the following: tin, cobalt, iron, molybdenum, manganese, copper, barium, and chromium.

2. The method according to claim 1, characterized in that, The light hydrocarbon is a C4 fraction, and the C4 olefin content in the C4 fraction is greater than 50% by weight.

3. The method according to claim 1, characterized in that, The catalytic cracking reaction conditions in the first reactor are as follows: The reaction temperature is 550-650℃; The reaction time is 0.1-5 seconds; and / or The weight ratio of the agent to the oil is (5-30):

1.

4. The method according to claim 3, characterized in that, The first raw material is preheated and steam atomized before entering the first reactor. The preheating temperature is 180-350℃, and the water-oil weight ratio is (0.05-0.5):

1.

5. The method according to claim 1, characterized in that, The catalytic cracking reaction conditions in the second reactor are as follows: The reaction temperature is 450-600℃; and / or Heavy hourly space velocity is 1-20 hours -1 .

6. The method according to claim 1, characterized in that, The catalytic cracking reaction conditions in the third reactor are as follows: The reaction temperature is 600-720℃; The reaction time is 0.1-3 seconds; and / or The weight ratio of the agent to the oil is (5-50):

1.

7. The method according to claim 6, characterized in that, The second raw material is introduced into the third reactor after being atomized by steam, with a water-to-oil weight ratio of (0.05-0.5):

1.

8. The method according to claim 1, characterized in that, The weight ratio of fresh catalyst to reduced and regenerated catalyst injected into the third reactor is 0.005-0.3:

1.

9. The method according to claim 1, characterized in that, The third reactor is equipped with a main reaction section and one or more second raw material feeding sections.

10. The method according to claim 9, characterized in that, The one or more second feed sections are each independently located in the middle to upstream of the third reactor; and / or The catalyst density in each of the second feed sections is 120-290 kg / m³. 3 .

11. The method according to claim 1, characterized in that, In the catalyst reducer, the reduction temperature is 550-700℃ and / or the reduction time is 2-20 minutes.

12. The method according to claim 1, characterized in that, Based on the dry weight of the catalyst, the catalyst comprises 0.005-3% by weight of metal oxide.

13. The method according to claim 1, characterized in that, The catalyst includes: 0-70 parts by weight of clay, 5-99 parts by weight of adhesive, 1-60 parts by weight of zeolite, and 0.001-5 parts by weight of metal oxides, And the total weight of the catalyst is 100 parts by weight; The adhesive is an inorganic oxide adhesive; The zeolite includes mesoporous zeolite and optionally macroporous zeolite, wherein the mesoporous zeolite is ZSM series zeolite and / or ZRP zeolite, and the macroporous zeolite is selected from one or more of rare earth Y-type zeolite, rare earth hydrogen Y-type zeolite, ultrastable Y-type zeolite and high silica Y-type zeolite.

14. The method according to claim 13, characterized in that, The catalyst includes: 5-60 parts by weight of clay, 10-80 parts by weight of adhesive, 5-45 parts by weight of zeolite, and 0.005-2 parts by weight of metal oxide, The total weight of the catalyst is 100 parts by weight.

15. The method according to claim 14, characterized in that, The catalyst includes: 10-50 parts by weight of clay, 20-70 parts by weight of adhesive, 10-40 parts by weight of zeolite; and 0.005-2 parts by weight of metal oxide.

16. The method according to claim 13, characterized in that, The adhesive is silicon dioxide and / or aluminum oxide; The clay is kaolin and / or hydrous kaolin.

17. The method according to claim 13, characterized in that, The mesoporous zeolite accounts for 5-100% of the total weight of the zeolite.

18. The method according to claim 13, characterized in that, The mesoporous zeolite accounts for 50-90% of the total weight of the zeolite.

19. The method according to claim 13, characterized in that, The mesoporous zeolite accounts for 20-50% of the total weight of the zeolite.

20. A catalytic cracking system for carrying out the method of any one of claims 1-19, comprising: The catalytic cracking reaction unit includes: The first reactor is provided with a pre-lifting medium inlet, a first reduction and regeneration catalyst inlet, a first raw material inlet, and a first oil agent outlet from bottom to top. The second reactor is provided with a first oil mixture inlet and a third oil mixture inlet, and the first oil outlet of the first reactor extends into the second reactor through the first oil mixture inlet of the second reactor; The third reactor, arranged from bottom to top, includes a pre-lifting section, a feed section, a main reaction section, and an outlet section. The bottom of the pre-lifting section has a second reduction regeneration catalyst inlet, a fresh catalyst inlet, and a pre-lifting medium inlet. The feed section has a difficult-to-convert feedstock inlet, a circulating catalyst inlet, and an optional catalyst outlet. The outlet section of the third reactor extends into the second reactor through the third oil-agent mixture inlet of the second reactor. An oil-solvent separation device is provided with an oil inlet, a catalyst outlet, and a reaction product outlet. The oil inlet of the oil-solvent separation device is connected to a second reactor, so that the oil-solvent mixture from the second reactor is separated into reaction oil gas and catalyst to be generated by the oil-solvent separation device. A settling device is provided inside the second reactor for settling and collecting the catalyst to be generated after being separated by the oil-agent separation device. A stripping section is provided below the settling device for stripping the catalyst to be generated. The stripping section is provided with a catalyst outlet and a stripping medium inlet. A reaction product separation unit, which is connected to an oil separation device, is used to separate the reaction oil and gas separated by the oil separation device. The regenerator includes a catalyst inlet, an oxygen-containing gas inlet, a gas distributor, a cyclone separator, a regenerated flue gas pipeline, and a regenerated catalyst outlet; the catalyst inlet of the regenerator is in fluid communication with the catalyst outlet of the stripping section; and A catalyst reducer is provided with a reduction medium inlet, a regeneration catalyst inlet, and at least one reduction-regeneration catalyst outlet. The regeneration catalyst inlet of the catalyst reducer is connected to the regeneration catalyst outlet of the regeneration catalyst, so that the regeneration catalyst from the regeneration catalyst is reduced within the catalyst reducer. One reduction-regeneration catalyst outlet of the catalyst reducer is in fluid communication with a first reduction-regeneration catalyst inlet of a first reactor, so that a portion of the reduction-regeneration catalyst is recycled back to the first reactor. One reduction-regeneration catalyst outlet of the catalyst reducer is in fluid communication with a second reduction-regeneration catalyst inlet of a third reactor, so that a portion of the reduction-regeneration catalyst is recycled back to the third reactor.

21. The catalytic cracking system according to claim 20, characterized in that, The feed section of the third reactor includes a first feed section and a second feed section, and an external catalyst circulation pipeline connecting the first feed section and the second feed section is provided.

22. The catalytic cracking system according to claim 21, characterized in that, The diameter ratio of the first and second feed sections to the main reaction section of the third reactor is independently 1.2-1.5:

1.

23. The catalytic cracking system according to claim 20, characterized in that, The third reactor includes two feed sections connected in sequence. The first feed section is connected to the pre-lifting section, and the second feed section is connected to the main reaction section. An external catalyst circulation pipeline connecting the first feed section and the second feed section is provided.

24. The catalytic cracking system according to claim 23, characterized in that, The distance from the connection port of the external catalyst circulation pipe on the first feed section to the bottom of the first feed section is 0 to 10% of the height of the second feed section; and / or the distance from the outlet of the catalyst on the second feed section to the bottom of the second feed section is 5% to 20% of the height of the second feed section.

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