Fluid catalytic conversion process for preparing low-carbon olefins

Abstract

A fluidized catalytic conversion process for preparing low carbon olefins, the process includes the steps of: 1) introducing an olefin-rich feedstock into a fluidized catalytic conversion reactor and contacting it with a catalyst at a temperature of 650°C or higher for reaction; 2) separating the oil and gas obtained from the reaction to obtain a stream containing C5 olefins or higher carbon number olefins; and 3) returning at least a part of the stream containing C5 olefins or higher carbon number olefins to step 1) for continuing reaction. The fluidized catalytic conversion process can effectively increase the yield of low carbon olefins, improve the selectivity, and increase the ethylene / propylene ratio of the product.

Description

Detailed Description of the Invention

[0001] [Cross - Reference to Related Applications] This application claims priority based on Chinese Patent Application No. 202110031544.4, titled "Contact Conversion Method for Preparing Ethylene, Propylene and Butylene", filed on November 1, 2021, and Chinese Patent Application No. 202110031545.9, titled "Contact Conversion Method for Preparing Ethylene and Propylene", filed on November 1, 2021. The content thereof is incorporated herein by reference in its entirety.

[0002] [Technical Field] This application relates to the technical field of fluidized catalytic conversion. In particular, it relates to a fluidized catalytic conversion method for preparing light olefins (also referred to as lower olefins).

[0003] [Background Art] Propylene and ethylene are two of the most important basic raw materials for the modern petrochemical industry. However, with the increase in oilfield production, the available yield of conventional crude oil has gradually decreased, the quality of crude oil has deteriorated, and it has become heavier. Currently, the production capacity of light olefins is increasing rapidly, but the demand for light olefins in the market has not yet been met.

[0004] As important chemical intermediates, ethylene and propylene are increasingly in demand and are mainly used in the production of various important organic chemical raw materials, synthetic resins, synthetic rubbers, various fine chemicals, etc. Ethylene is one of the chemical products with the largest yield in the world, accounting for more than 75% of the total petrochemical product yield in the world; the main bulk downstream products of ethylene mainly include polyethylene, ethylene oxide, ethylene glycol, polyvinyl chloride, styrene, vinyl acetate, etc. Propylene is an important organic chemical raw material and is mainly used in the preparation of acrylonitrile, propylene oxide, acetone, etc.

[0005] Conventional routes for preparing ethylene and propylene by steam cracking have a large requirement for light hydrocarbons such as naphtha. The steam cracking feedstock mainly includes light hydrocarbons (such as ethane, propane and butane), naphtha, diesel oil, condensate oil and hydrotreated tail oil. Among them, the mass fraction of naphtha accounts for more than 50%. Typical naphtha steam cracking has an ethylene yield of about 29-34% and a propylene yield of 13-16%. The lower ethylene / propylene output ratio makes it difficult to meet the current situation of light olefin requirements.

[0006] Chinese Patent Application No. CN101092323A discloses a method for preparing ethylene and propylene from a mixture of C4-C8 olefins, including reacting a mixture of C4-C8 olefins at a reaction temperature of 400-600 °C and an absolute pressure of 0.02-0.3 MPa, and recycling 30-90 wt% of the C4 fraction to the reactor after separation in a separator for further cracking. This method mainly improves the olefin conversion rate by recycling the C4 fraction. The obtained ethylene and propylene account for more than 62% of the total amount of the olefin feedstock, but it is troubled by problems including a relatively low ethylene / propylene ratio that cannot be flexibly adjusted according to market requirements, low reaction selectivity, a high butylene content in the product, and energy consumption for C4 separation.

[0007] Chinese Patent Application No. CN101239878A discloses a method using a mixture rich in C4+ olefins as a raw material. The method includes reacting at a reaction temperature of 400-680 °C, a reaction pressure of -0.09 MPa to 1.0 MPa and a weight hourly space velocity of 0.1-50 h -1 . The obtained product has an ethylene / propylene ratio of less than 0.41. As the temperature rises, the ethylene / propylene ratio increases, and the production of hydrogen, methane and ethane increases.

[0008] On the one hand, the olefin production route also includes non-petroleum routes. That is, the olefin production route includes a method for producing light olefins mainly containing ethylene and propylene by using oxygen-containing organic compounds as raw materials, typically by using methanol or dimethyl ether, which is abbreviated as MTO. Methanol or dimethyl ether is a typical oxygen-containing organic compound, and the reaction for producing light olefins from it has the characteristics of rapid reaction, strong heat release, low ratio of catalyst to alcohol, and long reaction induction period, and the rapid deactivation of the catalyst is the main problem in the MTO process. A scientific and efficient method for solving problems such as the long reaction induction period and easy deactivation of the catalyst in the MTO process has always been a major topic in the future of the majority of scientific researchers and technicians.

[0009] Therefore, in the art, there is a need for a new fluidized catalytic conversion method for producing ethylene and propylene in high yields and achieving efficient utilization of resources.

[0010] [Summary of the Invention] The object of the present application is to provide a fluidized catalytic conversion method for preparing light olefins (such as ethylene, propylene and butylene), which can simultaneously improve the yield and selectivity of light olefins and increase the ethylene / propylene ratio of the product.

[0011] To achieve the above object, the present application provides a fluidized catalytic conversion method for preparing light olefins, and the method includes the following steps: 1) A step of introducing an olefin-rich feedstock into a fluidized catalytic conversion reactor, contacting it with a catalytic conversion catalyst having a temperature of 650 °C or higher, and reacting under the first catalytic conversion conditions, wherein the olefin-rich feedstock has an olefin content of 50% by weight or more; 2) Separating the effluent of the fluid catalytic cracking reactor to obtain reaction product vapor and spent catalyst, separating the reaction product vapor to obtain a stream containing ethylene, propylene, butylene and C5+ olefins; and 3) Recirculating at least a portion of the C5+ olefin-containing stream to step 1) for further reaction, The first catalytic cracking conditions are: A reaction temperature of 600 to 800 °C, preferably 630 to 780 °C; A reaction pressure of 0.05 to 1 MPa, preferably 0.1 to 0.8 MPa; A reaction time of 0.01 to 100 seconds, preferably 0.1 to 80 seconds; (1 to 200):1 weight ratio of the catalytic cracking catalyst to the olefin-rich feedstock, preferably (3 to 180):1 weight ratio of the catalytic cracking catalyst to the olefin-rich feedstock.

[0012] Preferably, the method further includes the following steps: 4) Recirculating at least a portion of the butylene separated in step 2) upstream of the catalytic cracking reactor, which is the position where the olefin-rich feedstock is introduced into contact with the catalytic cracking catalyst, and reacting under second catalytic cracking conditions. The second catalytic cracking conditions are: A reaction temperature of 650 to 800 °C, preferably 680 to 780 °C, A reaction pressure of 0.05 to 1 MPa, preferably 0.1 to 0.8 MPa, A reaction time of 0.01 to 10 seconds, preferably 0.05 to 8 seconds, (20 to 200):1 weight ratio of the catalytic cracking catalyst to the butylene, preferably (30 to 180):1 weight ratio of the catalytic cracking catalyst to the butylene.

[0013] Preferably, the method further includes the following steps: 1a) A step of introducing an oxygen-containing organic compound downstream of the catalytic conversion reactor and reacting it under third catalytic conversion conditions, where the downstream of the catalytic conversion reactor is the position where the olefin-rich feedstock is introduced for contacting the catalytic conversion catalyst after the reaction of step 1): The third catalytic conversion conditions are a reaction temperature of 300 to 550 °C, preferably 400 to 530 °C, a reaction pressure of 0.01 to 1 MPa, preferably 0.05 to 1 MPa, a reaction time of 0.01 to 100 seconds, preferably 0.1 to 80 seconds, (1 to 100):1 weight ratio of the catalytic conversion catalyst to the oxygen-containing organic compound feedstock, preferably (3 to 50):1 weight ratio of the catalytic conversion catalyst to the oxygen-containing organic compound feedstock.

[0014] In the method of the present application, an olefin-rich feedstock is subjected to a cracking reaction on a catalyst having a high temperature (≥650 °C), and then the olefin-containing stream obtained by separating the product is introduced back into the reactor for further reaction. As a result, the yield of light olefins can be effectively increased, the selectivity can be improved, and the ethylene / propylene ratio of the product can be enhanced; at the same time, the production of hydrogen, methane, and ethane can be reduced, especially the production of methane can be suppressed. Furthermore, the further reaction of olefins in the separated product can further improve the utilization rate of petroleum resources.

[0015] Other features and advantages of the present application are described in detail in the following detailed description.

[0016] [Brief Description of the Drawings] The drawings forming a part of this specification are provided to assist in the understanding of the present application and should not be regarded as limiting. The present application can be interpreted with reference to the drawings in combination with the following detailed description. In the drawings: FIG. 1 shows a schematic flow diagram of a preferred embodiment of the method of the present application.

[0017] Figure 2 shows a schematic flow diagram of another preferred embodiment of the method of the present application.

[0018] Figure 3 shows a schematic flow diagram of another preferred embodiment of the method of the present application.

[0019] [Brief Explanation of Signs] 101 Pipeline 102 Pipeline 103 Catalytic Conversion Reactor 104 Pipeline 105 Regenerator 106 Pipeline 107 Pipeline 108 Pipeline 109 Heat Exchanger 110 Transfer Line 111 Product Rectification Tower 112 Pipeline 113 Pipeline 114 Pipeline 115 Pipeline 116 Pipeline 117 Pipeline 118 Olefin Separator 119 Pipeline 120 Pipeline 201 Pipeline 202 Catalytic Conversion Reactor 203 Pipeline 204 Pipeline 205 Heat Exchanger 206 Heat Exchanger 207 Outlet Section 208 Cyclone Separator 209 Plenum Chamber 210 Stripping Section 211 Pipeline 212 Standpipe 213 Regenerator 214 Pipeline 215 Pipeline 216 Pipeline 217 Pipeline 218 Pipeline 219 Reactor Vapor Line 220 Rectification Tower 221 Pipeline 222 Pipeline 223 Pipeline 224 Pipeline 225 Pipeline 226 Pipeline 227 Pipeline 228 Olefin Separator 301 Pipeline 302 Catalytic Conversion Reactor 303 Pipeline 304 Pipeline 305 Heat Exchanger 306 Heat Exchanger 307 Outlet section 308 Cyclone separator 309 Plenum chamber 310 Stripping section 311 Pipeline 312 Standpipe 313 Regenerator 314 Pipeline 315 Pipeline 316 Pipeline 317 Pipeline 318 Pipeline 319 Reactor vapor line 320 Rectification column 321 Pipeline 322 Pipeline 323 Pipeline 324 Pipeline 325 Pipeline 326 Pipeline 327 Pipeline 328 Olefin separator 329 Pipeline [Mode for Carrying Out the Invention] This application will be described in more detail below with reference to the drawings and specific embodiments thereof. It should be noted that the specific embodiments of this application are provided for illustrative purposes only and are not intended to limit in any way.

[0020] In the context of this application, any specific numerical values, including the boundary points of numerical ranges, are not limited to their exact values and should be construed as further encompassing all values close to the exact values, for example, all values within ±5% of the exact values. Further, with respect to any numerical range described herein, any combination can be made between the boundary points of the range, between each boundary point and any specific value within the range, or between any two specific values within the range, and one or more new numerical ranges can be provided. Here, the new numerical ranges should also be regarded as specifically described in this application.

[0021] Unless otherwise specified, the terms used in this specification have the same meaning as commonly understood by those skilled in the art; if a term is defined in this specification and its definition is different from the ordinary understanding in the technical field, the definition provided in this specification shall prevail.

[0022] In the context of the present application, the expression "C5+" means having at least 5 carbon atoms. For example, the term "C5+ olefin" refers to an olefin having at least 5 carbon atoms, while the term "C5+ fraction" refers to a fraction in which the compound has at least 5 carbon atoms.

[0023] In the context of the present application, in addition to the explicitly stated subject matter, any subject matter, or a subject matter not mentioned, is considered to be the same as that known in the art without any change. Furthermore, any of the embodiments described herein can be freely combined with one or more different embodiments described herein, and the technical solutions or ideas obtained in this way are considered to be part of the original disclosure or original description of the present application. Unless it is obvious to those skilled in the art that such a combination is clearly unreasonable, the said technical solutions or ideas should not be considered as new matters not disclosed or anticipated in this specification.

[0024] All patent documents and non-patent documents cited herein, including but not limited to textbooks and academic papers, are hereby incorporated by reference in their entirety.

[0025] As a result of studying the differences in the product distributions formed by the catalytic cracking of alkanes and olefins, the inventors of the present application surprisingly discovered the following: the effect of catalytic cracking of olefins on the production of light olefins is significantly superior to that of alkanes; the catalytic cracking of olefins under high-temperature catalytic reaction conditions not only simultaneously improves the yields and selectivities of ethylene, propylene, and butylene, but also significantly reduces the production of by-products such as methane, improves the cracking effect and the resource utilization rate, thereby arriving at the technical solution of the present application.

[0026] As described above, the present application provides a fluidized catalytic conversion method for producing light olefins, and the method includes the following steps: 1) A step of introducing an olefin-rich feedstock into a fluidized catalytic cracking reactor, wherein the olefin-rich feedstock contacts a catalytic cracking catalyst having a temperature of 650 °C or higher, and the olefin-rich feedstock has an olefin content of 50% by weight or more; 2) Separating the effluent of the fluidized catalytic cracking reactor to obtain reaction product vapor and spent catalyst, and separating the reaction product vapor to obtain an ethylene, propylene, butylene and C5+ olefin-containing stream; and 3) A step of recycling at least a part of the C5+ olefin-containing stream to step 1) for further reaction.

[0027] In the method of the present application, an olefin-rich material is used as a feedstock to be subjected to a cracking reaction on a catalyst at a high temperature (≧650 °C), and then the olefin-containing stream obtained by separating the product is reintroduced into the fluidized catalytic cracking reactor for further reaction. Thereby, the yield of light olefins can be effectively increased, the selectivity can be improved, the ethylene / propylene ratio of the product can be improved, and at the same time, the production of hydrogen, methane and ethane can be reduced, and in particular, the production of methane can be suppressed. In addition, the further reaction of the olefin-rich olefin-containing stream in the cracking product can further improve the utilization rate of petroleum resources.

[0028] In a preferred embodiment, the reaction in step 1) is carried out under first catalytic cracking conditions. The first catalytic cracking conditions include a reaction temperature of 600-800 °C; a reaction pressure of 0.05-1 MPa; a reaction time of 0.01-100 seconds; and a weight ratio of the catalytic cracking catalyst to the olefin-rich feedstock of (1-200):1.

[0029] In a more preferred embodiment, the first catalytic cracking conditions include a reaction temperature of 630-780 °C; a reaction pressure of 0.1-0.8 MPa; a reaction time of 0.1-80 seconds; and a weight ratio of the catalytic cracking catalyst to the olefin-rich feedstock of (3-180):1.

[0030] In a particularly preferred embodiment, the first catalytic conversion conditions include a reaction temperature of 650 to 780 °C, a reaction pressure of 0.1 to 0.7 MPa, a reaction time of 0.1 to 20 seconds, and a weight ratio of the catalytic conversion catalyst to the olefin-rich feedstock of (3 to 150):1.

[0031] In a preferred embodiment, the olefin-rich feedstock used in step 1) is a feedstock having an olefin content of 80 wt% or more, preferably 90 wt% or more, more preferably a pure olefin feedstock. According to the present application, the higher the olefin content in the olefin-rich feedstock used, the higher the yields of ethylene, propylene and butylene obtained by the catalytic conversion reaction, and the further suppression of the formation of hydrogen, methane and ethane in the product.

[0032] In a preferred embodiment, the olefins in the olefin-rich feedstock consist essentially of C5+ olefins. For example, 80% or more, 85% or more, 90% or more, or 95% or more of the olefins in the olefin-rich feedstock, more preferably 100% of the olefins, are C5+ olefins.

[0033] In some embodiments, the olefin-rich feedstock used in step 1) may be obtained from any one or more of the following sources: the C5+ fraction produced by an alkane dehydrogenation unit, the C5+ fraction produced by a catalytic cracking unit in an oil refinery, the C5+ fraction produced by a steam cracking unit in an ethylene plant, the olefin-rich C5+ fraction produced by an MTO process (methanol to olefins), and the olefin-rich C5+ by-product fraction of an MTP process (methanol to propylene), etc. In a preferred embodiment, the alkane feedstock for the alkane dehydrogenation unit can be obtained from at least one of naphtha, aromatic raffinate, and other light hydrocarbons. In actual production, alkane products from other petrochemical plants can also be used.

[0034] In some embodiments, the olefin-rich feedstock used herein is obtained by contacting an alkane with a dehydrogenation catalyst in a dehydrogenation reactor under catalytic dehydrogenation conditions. Here, the dehydrogenation conditions used include an inlet temperature of the dehydrogenation reactor of 400 to 700 °C, a volume space velocity of the alkane of 200 to 5000 h -1 and a reaction pressure of 0 to 0.1 MPa.

[0035] Preferably, the dehydrogenation catalyst consists of a carrier, an active component and a promoter supported on the carrier; based on the total weight of the dehydrogenation catalyst, the carrier is present in an amount of 60 to 90% by weight, the active component is present in an amount of 8 to 35% by weight, and the promoter is present in an amount of 0.1 to 5% by weight.

[0036] More preferably, the carrier may be alumina containing a modifier, where, based on the total weight of the dehydrogenation catalyst, the modifier may be present in an amount of 0.1 to 2% by weight, and the modifier may be La and / or Ce; the active component may be platinum and / or chromium; the promoter may be a composition of bismuth and an alkali metal component, or a composition of bismuth and an alkaline earth metal component, where the molar ratio of bismuth to the active component is 1:(5 to 50), the molar ratio of bismuth to the alkali metal component is 1:(0.1 to 5), and the molar ratio of bismuth to the alkaline earth metal component is 1:(0.1 to 5). Particularly preferably, the alkali metal component may be one or more selected from Li, Na and K; the alkaline earth metal component may be one or more selected from Mg, Ca and Ba.

[0037] In a preferred embodiment, the C5+ olefin-containing stream separated in step 2) has an olefin content of 50% by weight or more, for example, a C5+ olefin content of 50% by weight or more. The higher the olefin content in the C5+ olefin-containing stream, the better the recycling effect and the better the resource utilization.

[0038] According to the present application, in step 2), the reaction product vapor can be separated by a separation device commonly used in the art such as a product rectification column. In a preferred embodiment, the reaction product vapor can be separated by a separation system including a product rectification column and an olefin separator. In a more preferred embodiment, the reaction product vapor is first sent to a product rectification column and separated into ethylene, propylene, butylene, and an olefin-containing stream (for example, a fraction having a boiling point of 20 °C or higher), and then the olefin-containing stream is sent to an olefin separator for further separation into a C5+ olefin-containing stream to further increase their olefin content.

[0039] In a particularly preferred embodiment, step 2) further includes the following: 2a) Separating the effluent of the fluidized catalytic cracking reactor to obtain reaction product vapor and spent catalyst; 2b) Separating the reaction product vapor in a product rectification column to obtain ethylene, propylene, butylene, and a first olefin-containing stream; and 2c) Separating the first olefin-containing stream in an olefin separator to obtain a second olefin-containing stream rich in olefins, wherein the olefin content of the second olefin-containing stream is higher than that of the first olefin-containing stream, and recycling the second olefin-containing stream as the C5+ olefin-containing stream for further reaction to step 1). The separation system used in this embodiment can significantly improve the olefin content in the C5+ olefin-containing stream, which is returned to the fluidized catalytic cracking reactor for further reaction and reduces the influence of other impurities.

[0040] According to the present application, the fluidized catalytic cracking reactor can include one reactor or a plurality of reactors connected in series and / or in parallel.

[0041] According to the present application, the fluidized catalytic conversion reactor may be selected from a riser reactor, a fluidized bed reactor, an upward transfer line, a downward transfer line, or a combination of two or more thereof. The riser reactor may be an equal-diameter riser reactor or a diameter-converting riser reactor. The fluidized bed reactor may be an equal-linear velocity fluidized bed reactor or an equal-diameter fluidized bed reactor. The diameter-converting riser reactor may be, for example, a riser reactor as described in Chinese Patent No. CN1078094C.

[0042] In some preferred embodiments, the fluidized catalytic conversion reactor is a fluidized bed reactor, and the C5+ olefin-containing stream separated in step 2) can be recycled to the bottom of the fluidized bed reactor for further reaction. In other preferred embodiments, the fluidized catalytic conversion reactor is a riser reactor, and butylene and the C5+ olefin-containing stream separated in step 2) can be recycled to the riser reactor for further reaction.

[0043] In a preferred embodiment, the fluidized catalytic conversion method of the present application further includes the following steps: 4) Recycling at least a part of the butylene separated in step 2) upstream of the catalytic conversion reactor, which is the position where the olefin-rich feedstock comes into contact with the catalytic conversion catalyst, and reacting under the second catalytic conversion conditions: The second catalytic conversion conditions include a reaction temperature of 650 to 800 °C, a reaction pressure of 0.05 to 1 MPa, a reaction time of 0.01 to 10 seconds, and a weight ratio of the catalytic conversion catalyst to butylene of (20 to 200):1.

[0044] More preferably, the second catalytic conversion conditions include a reaction temperature of 680 to 780 °C, a reaction pressure of 0.1 to 0.8 MPa, a reaction time of 0.05 to 8 seconds, and a weight ratio of the catalytic conversion catalyst to butylene of (30 to 180):1.

[0045] In some preferred embodiments, the fluidized catalytic conversion method of the present application further includes the following steps: 1a) A step of introducing an oxygen-containing organic compound downstream of the contact conversion reactor and reacting it under third contact conversion conditions. Downstream of the contact conversion reactor is the position where the olefin-rich feedstock is introduced to contact the contact conversion catalyst after the reaction in step 1). The third contact conversion conditions include a reaction temperature of 300 to 550 °C, a reaction pressure of 0.01 to 1 MPa, a reaction time of 0.01 to 100 seconds, and a weight ratio of the contact conversion catalyst to the oxygen-containing organic compound raw material of (1 to 100):1.; More preferably, the third contact conversion conditions include a reaction temperature of 400 to 530 °C, a reaction pressure of 0.05 to 1 MPa, a reaction time of 0.1 to 80 seconds, and a weight ratio of the contact conversion catalyst to the oxygen-containing organic compound raw material of (3 to 50):1.

[0046] Particularly preferably, the oxygen-containing organic compound includes at least one of methanol, ethanol, dimethyl ether, methyl ethyl ether, and ethyl ether. For example, oxygen-containing organic compounds such as methanol or dimethyl ether may be obtained from coal-based or natural gas-based synthesis gas.

[0047] In a preferred embodiment, the contact conversion catalyst used herein can include molecular sieves, inorganic oxides, and optionally, clays. The contact conversion catalyst includes 1 to 50 wt% molecular sieves, 5 to 99 wt% inorganic oxides, and 0 to 70 wt% clays based on the weight of the catalyst.

[0048] In a more preferred embodiment, in the contact conversion catalyst, the molecular sieve functions as an active component. The molecular sieve may be selected from mesoporous molecular sieves and / or microporous molecular sieves; the molecular sieve may include 50 to 100 wt% mesoporous molecular sieves and 0 to 50 wt% microporous molecular sieves based on the total weight of the molecular sieve. It is particularly preferred that the molecular sieve does not include macroporous molecular sieves (e.g., Y-type molecular sieves).

[0049] In yet another preferred embodiment, the mesoporous molecular sieve may be a ZSM molecular sieve. For example, the ZSM molecular sieve may be one or more selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, and ZSM-48. The microporous molecular sieve may be a SAPO molecular sieve and / or an SSZ molecular sieve. For example, the SAPO molecular sieve may be one or more selected from the group consisting of SAPO-34, SAPO-11, and SAPO-47. The SSZ molecular sieve may be one or more selected from the group consisting of SSZ-13, SSZ-39, and SSZ-62.

[0050] In a more preferred embodiment, in the catalytic cracking catalyst, the inorganic oxide functions as a binder, and preferably the inorganic oxide may be selected from silicon dioxide (SiO2) and / or aluminum oxide (Al2O3).

[0051] In a more preferred embodiment, in the catalytic cracking catalyst, the clay functions as a matrix, and preferably the clay may be selected from kaolin and / or halloysite.

[0052] In a more preferred embodiment, the catalytic cracking catalyst used herein can also be loaded with a modifying element. For example, the catalytic cracking catalyst may contain 0.1 to 3 wt% of the modifying element based on the weight of the catalyst; the modifying element may be one or more selected from Group VIII metals, Group IVA metals, Group VA metals, and rare earth metals. In an even more preferred embodiment, the modifying element may be one or more selected from phosphorus, iron, cobalt, and nickel.

[0053] In some preferred embodiments, the fluid catalytic cracking method of the present application further includes the following steps: 5) A step of regenerating the used catalyst obtained by separation in Process 2 by coke combustion to obtain a regenerated catalyst, adjusting the temperature of the regenerated catalyst to 650 °C or higher, and then recycling the regenerated catalyst to a fluidized catalytic cracking reactor for use as a catalytic cracking catalyst.

[0054] In this embodiment, the deactivated used catalyst can be regenerated by coke combustion, and the catalyst can be recycled, improving the utilization rate of the catalyst. The regenerated catalyst is subjected to temperature adjustment such as preheating to 650 °C or higher, and then recycled to the reactor, whereby the catalytic effect of the catalyst can be improved.

[0055] As is well known to those skilled in the art, the thermal energy for preheating the regenerated catalyst can be provided electrically or by combustion of by-product gas of the method of the present application, inferior heavy oil, fuel oil, and fuel gas from other units in the oil refining section.

[0056] In a preferred embodiment, as shown in FIG. 1, the fluidized catalytic cracking method for producing light olefins of the present application is carried out as follows: An olefin-rich feedstock and a pre-lifting medium having an olefin content of 50% by weight or more are introduced into the bottom of a fluidized catalytic cracking reactor (fluidized bed reactor) 103 via pipeline 101, contact and react with the regenerated catalytic cracking catalyst introduced via pipeline 108, and move upward in the fluidized catalytic cracking reactor 103 under the action of the pre-lifting medium.

[0057] The used catalyst produced in the reaction is withdrawn from the upper end of the fluidized catalytic cracking reactor 103, sent to a regenerator 105 through an outlet pipeline 104, main air is introduced into the regenerator 105 through a pipeline 106 to burn the coke on the used catalyst and regenerate the used catalyst; a supplementary fuel is introduced into the regenerator 5 through a pipeline 107 for combustion, and the regenerated catalyst is preheated to 650 °C or higher; the preheated regenerated catalyst is introduced into the bottom of the fluidized catalytic cracking reactor 103 through a pipeline 108.

[0058] The reaction product vapor generated in the reaction is withdrawn from the upper end of the fluidized catalytic cracking reactor 103 and sent through the pipeline 110 to the subsequent product rectification column 111 for product separation. The separated hydrogen, methane, and ethane are withdrawn via the pipeline 112, and ethylene is withdrawn through the pipeline 113. Propylene is withdrawn through the pipeline 114. Propane and butane are withdrawn through the pipeline 115. Butylene is withdrawn through the pipeline 116. The stream containing residual olefins (the fraction in the product with a boiling point of 20 °C or higher) is sent through the pipeline 117 to the olefin separator 118. The olefin-depleted stream obtained by separation (mainly containing alkanes, a small amount of aromatic hydrocarbons, naphthenes, etc.) is withdrawn from the pipeline 119. The separated stream containing C5+ olefins and having an olefin content of 50% or more is sent through the pipeline 120 to the heat exchanger 109, preheated to 650 °C or higher, and then sent through the pipeline 102 to the bottom of the fluidized catalytic cracking reactor 103 for further reaction with the regenerated catalytic cracking catalyst.

[0059] In another preferred embodiment, as shown in Figure 2, the fluidized catalytic cracking method for producing light olefins of the present application is implemented as follows: It is introduced into the pre-lifting medium from the bottom of the fluidized catalytic cracking reactor (diameter conversion riser reactor) 202 via pipeline 201. The regenerated fluidized catalytic cracking catalyst from pipeline 217 moves upward along the fluidized catalytic cracking reactor 202 under the lifting action of the pre-lifting medium. The olefin-rich feedstock is injected into the bottom of the fluidized catalytic cracking reactor 202 via pipeline 203 together with the atomizing steam from pipeline 204, contacts the hot catalytic cracking catalyst for the reaction, and moves upward. The reaction product vapor and the spent catalyst produced are sent to the cyclone separator 208 in the disengager through the outlet section 207 to separate the spent catalyst from the reaction product vapor. The reaction product vapor is sent to the plenum chamber 209, and the fine powder of the spent catalyst is returned to the disengager through the dip leg. The spent catalyst in the disengager is sent to the stripping section 210, where it contacts the stripping steam from pipeline 211. The product vapor removed from the spent catalyst is sent to the plenum chamber 209 after passing through the cyclone separator. The stripped spent catalyst is sent to the regenerator 213 through the standpipe 212. The main air is introduced into the regenerator through pipeline 216 to burn the coke on the spent catalyst to regenerate the deactivated spent catalyst, and the make-up fuel is introduced into the regenerator through pipeline 214 for combustion. As a result, the regenerated catalyst is preheated to 650 °C or higher. The exhaust gas is sent to the exhaust gas turbine via pipeline 215, and the preheated regenerated catalyst is sent to the fluidized catalytic cracking reactor 202 via pipeline 217. The reaction product vapor is sent to the subsequent rectification column 220 through the reaction vapor line 219. The separated hydrogen, methane, and ethane are withdrawn through pipeline 221. Ethylene is withdrawn through pipeline 222. Propylene is withdrawn through pipeline 223. Butylene is withdrawn through pipeline 224 and optionally sent to the heat exchanger 206 for preheating. Then, it is recycled to the fluidized catalytic cracking reactor 202 upstream of the supply position of the olefin-rich feedstock for further reaction. Propane and butane are withdrawn through pipeline 225.The stream containing residual olefins is sent through pipeline 226 to olefin separator 228. The olefin-depleted stream obtained by separation is withdrawn through pipeline 218, and the separated stream containing C5+ olefins and having an olefin content of 50% or more is sent through pipeline 227 to heat exchanger 205 for preheating and then sent from pipeline 203 together with an olefin-rich feedstock to fluidized catalytic cracking reactor 202 for further reaction.

[0060] In another preferred embodiment, as shown in FIG. 3, the fluidized catalytic cracking process for producing light olefins of the present application is carried out as follows: The pre-lift medium is introduced from the bottom of the fluidized catalytic cracking reactor (diameter conversion riser reactor) 302 through pipeline 301. The regenerated fluidized catalytic cracking catalyst from pipeline 317 moves upward along the fluidized catalytic cracking reactor 302 under the lift action of the pre-lift medium. The olefin-rich feedstock is injected into the bottom of the fluidized catalytic cracking reactor 302 through pipeline 303 together with the atomizing steam from pipeline 304 and contacts the high-temperature catalytic cracking catalyst for the reaction. The methanol feed is introduced through pipeline 329, mixed with the materials in reactor 302, contacts the catalytic cracking catalyst for the reaction, and moves upward. The reaction product vapor and the spent catalyst produced are sent to the cyclone separator 308 in the disengager through the outlet section 307 to separate the spent catalyst from the reaction product vapor. The reaction product vapor is sent to the plenum chamber 309, and the fine powder of the spent catalyst is returned to the disengager through the dip leg. The spent catalyst in the disengager is sent to the stripping section 310, where it contacts the stripping steam from pipeline 311. The product vapor stripped from the spent catalyst is sent to the plenum chamber 309 after passing through the cyclone separator. The stripped spent catalyst is sent to the regenerator 313 through the standpipe 312. The main air is introduced into the regenerator through pipeline 316 to burn the coke on the spent catalyst to regenerate the deactivated spent catalyst. The make-up fuel is introduced into the regenerator through pipeline 314 for combustion. As a result, the regenerated catalyst is preheated to 650 °C or higher. The exhaust gas is sent to the exhaust gas turbine through pipeline 315, and the preheated regenerated catalyst is sent to the fluidized catalytic cracking reactor 302 through pipeline 317. The reaction product vapor is sent to the subsequent rectification column 320 through the reaction vapor line 319. The separated hydrogen, methane, and ethane are withdrawn through pipeline 321. Ethylene is withdrawn through pipeline 322. Propylene is withdrawn through pipeline 323.Butylene is withdrawn through pipeline 324 and optionally sent to heat exchanger 306 for preheating and then recycled to fluidized catalytic cracking reactor 302 upstream of the feed location of the olefin-rich feedstock for further reaction. Propane and butane are withdrawn through pipeline 325. The stream containing residual olefins is sent through pipeline 326 to olefin separator 328. The olefin-depleted stream obtained by separation is withdrawn through pipeline 318. The separated stream containing C5+ olefins and having an olefin content of 50% or more is sent through pipeline 327 to heat exchanger 305 for preheating and then sent to fluidized catalytic cracking reactor 302 together with the olefin-rich feedstock from pipeline 303 for further reaction.

[0061] In particularly preferred specific examples, the present application provides the following technical solutions: 1. A catalytic conversion method for producing ethylene, propylene and butylene, comprising the following steps: Contacting an olefin-rich feedstock with a catalytic conversion catalyst having a temperature of 650 °C or higher in a catalytic conversion reactor under catalytic conversion conditions to obtain a reaction product vapor and a spent catalyst; the olefin-rich feedstock has an olefin content of 50% by weight or more; Separating the reaction product vapor into ethylene, propylene, butylene and an olefin-containing stream in a separation system and recycling the olefin-containing stream to the catalytic conversion reactor for further reaction.

[0062] 2. The method according to item 1, wherein the olefin-rich feedstock has an olefin content of 80% by weight or more, preferably 90% by weight or more, and more preferably is a pure olefin feedstock.

[0063] 3. The method according to item 1 or 2, wherein the olefin in the olefin-rich feedstock is selected from C5+ olefins; Optionally, the olefin-rich feedstock is one or more of a C5+ fraction produced by an alkane dehydrogenation unit, a C5+ fraction produced by a catalytic cracking unit in an oil refinery, a C5+ fraction produced by a steam cracking unit in an ethylene plant, an olefin-rich C5+ by-product fraction of an MTO process, and an olefin-rich C5+ by-product fraction of an MTP process; Optionally, the alkane feedstock of the alkane dehydrogenation unit is one or more of naphtha, aromatic raffinate, and light hydrocarbons.

[0064] 4. The method according to item 1, wherein the catalytic conversion reactor is selected from the group consisting of a riser reactor, an isokinetic fluidized bed, an isoradial fluidized bed, an upward transfer line, and a downward transfer line, or a combined reactor in which two of them are connected in series, and the riser reactor is an isodiameter riser reactor or a variable diameter fluidized bed reactor.

[0065] 5. The method according to item 1, wherein the catalytic conversion conditions include the following: A reaction temperature of 600 to 750 °C, preferably a reaction temperature of 630 to 750 °C, more preferably a reaction temperature of 630 to 720 °C; A reaction pressure of 0.05 to 1 MPa, preferably a reaction pressure of 0.1 to 0.8 MPa, more preferably a reaction pressure of 0.2 to 0.5 MPa; A reaction time of 0.01 to 100 seconds, preferably a reaction time of 0.1 to 80 seconds, more preferably a reaction time of 0.2 to 70 seconds; (1 to 150):1, the weight ratio of the catalytic conversion catalyst to the olefin-rich feedstock, preferably (3 to 150):1, the weight ratio of the catalytic conversion catalyst to the olefin-rich feedstock, more preferably (4 to 120):1, the weight ratio of the catalytic conversion catalyst to the olefin-rich feedstock.

[0066] 6. The method according to item 1, wherein based on the weight of the catalytic conversion catalyst, the catalytic conversion catalyst contains 1 to 50 wt% of molecular sieve, 5 to 99 wt% of inorganic oxide, and 0 to 70 wt% of clay; Optionally, based on the total weight of the molecular sieve, the molecular sieve comprises 50-100 wt% of a mesoporous molecular sieve and 0-50 wt% of a microporous molecular sieve; Optionally, the mesoporous molecular sieve is a ZSM molecular sieve and the microporous molecular sieve is a SAPO molecular sieve.

[0067] 7. The method according to item 1, wherein, based on the weight of the catalytic conversion catalyst, the catalytic conversion catalyst further comprises 0.1-3 wt% of a modifying element; the modifying element is one or more selected from the group consisting of Group VIII metals, Group IVA metals, Group VA metals and rare earth metals.

[0068] 8. The method according to item 1, wherein the method further comprises the following; A step of regenerating the used catalyst by coke combustion to obtain a regenerated catalyst; a step of preheating the regenerated catalyst to 650 °C or higher, and then recycling it to the catalytic conversion reactor as the catalytic conversion catalyst.

[0069] 9. The method according to item 1, wherein the olefin-containing stream obtained from the separation system has an olefin content of 50 wt% or more.

[0070] 10. The method according to item 9, wherein the separation system includes a product rectification column and an olefin separator, and the method includes the following: Passing the reaction product vapor through the product rectification column to separate ethylene, propylene, butylene and a first olefin-containing stream; Sending the first olefin-containing stream to the olefin separator, separating a second olefin-rich olefin-containing stream, recycling the second olefin-containing stream to the bottom of the catalytic conversion reactor for further reaction, and the olefin content in the second olefin-containing stream is higher than that in the first olefin-containing stream.

[0071] 11. A catalytic conversion method for producing ethylene and propylene, the method comprising the following steps: S1 is a step of bringing a hydrocarbon oil feedstock having an olefin content of 50% by weight or more into contact with a catalytic conversion catalyst at a temperature of 650 ° C or more for the catalytic conversion reaction in the catalytic conversion reactor to obtain a reaction product vapor and a spent catalyst; S2 is a step of separating the reaction product vapor to obtain ethylene, propylene, butylene and an olefin-rich stream, and introducing the butylene and the olefin-rich stream into the catalytic conversion reactor for further reaction, respectively.

[0072] 12. The method according to item 11, wherein in step S2, the butylene is brought into contact with the catalytic conversion catalyst prior to the olefin-rich stream.

[0073] 13. The method according to item 11, wherein the olefin content in the olefin-rich stream is 50% by weight or more.

[0074] 14. The method according to item 11, wherein the olefin in the olefin-rich stream is a C5+ olefin.

[0075] 15. The method according to item 11, the method further comprising: regenerating the spent catalyst by coke combustion to obtain a regenerated catalyst; and preheating the regenerated catalyst and then recycling it to the catalytic conversion reactor.

[0076] 16. The method according to item 15, wherein the catalytic conversion catalyst comprises a preheated regenerated catalyst.

[0077] 17. The method according to item 11, wherein the catalytic conversion conditions include the following: A reaction temperature of 600 to 800 ° C, a reaction pressure of 0.05 to 1 MPa, a reaction time of 0.01 to 100 seconds, and a weight ratio of the catalytic conversion catalyst to the hydrocarbon oil feedstock of (1 to 200): 1; Preferably, a reaction temperature of 630 to 780 °C, a reaction pressure of 0.1 to 0.8 MPa, a reaction time of 0.1 to 80 seconds, and a weight ratio of the catalytic conversion catalyst to the hydrocarbon oil feedstock of (3 to 180):1; More preferably, a reaction temperature of 650 to 750 °C, a reaction pressure of 0.2 to 0.5 MPa, a reaction time of 0.2 to 70 seconds, and a weight ratio of the catalytic conversion catalyst to the hydrocarbon oil feedstock of (4 to 150):1.

[0078] 18. The method according to item 11, wherein The reaction conditions for the further reaction of butylene introduced into the catalytic reactor include: a reaction temperature of 650 to 800 °C, a reaction pressure of 0.05 to 1 MPa, a reaction time of 0.01 to 10 seconds, and a weight ratio of the catalytic conversion catalyst to butylene of (20 to 200):1; Preferably, a reaction temperature of 680 to 780 °C, a reaction pressure of 0.1 to 0.8 MPa, a reaction time of 0.05 to 8 seconds, and a weight ratio of the catalytic conversion catalyst to butylene of (30 to 180):1.

[0079] 19. The method according to item 11, wherein the hydrocarbon oil feedstock preferably has an olefin content of 80% by weight or more; preferably, the hydrocarbon oil feedstock has an olefin content of 90% by weight or more; more preferably, the hydrocarbon oil feedstock is a pure olefin raw material.

[0080] 20. The method according to item 11 or 19, wherein the olefin in the hydrocarbon oil feedstock is obtained from a C4+ fraction produced by dehydrogenation of an alkane feedstock, a C4+ fraction produced by a catalytic cracking unit in an oil refining section, a C4+ fraction produced by a steam cracking unit in an ethylene plant, a C4+ olefin-rich by-product fraction of an MTO process, and a C4+ olefin-rich by-product fraction of an MTP process; The alkane feedstock is at least one selected from the group consisting of naphtha, aromatic raffinate, and light hydrocarbons.

[0081] 21. The method according to item 11, wherein the catalytic conversion catalyst comprises 1 to 50% by weight of molecular sieve, 5 to 99% by weight of inorganic oxide, and 0 to 70% by weight of clay, based on the weight of the catalytic conversion catalyst; The molecular sieve is selected from mesoporous molecular sieves and / or microporous molecular sieves; Based on the weight of the catalytic conversion catalyst, the catalytic conversion catalyst further comprises 0.1 to 3% of a modifying element, and the modifying element is one or more selected from the group consisting of Group VIII metals, Group IVA metals, Group VA metals, and rare earth metals.

[0082] [Examples] Hereinafter, the present application will be described in more detail with reference to examples. All the feedstocks used in the examples are commercially available.

[0083] [Feedstock and Catalyst] The feedstocks I and II used in the following examples are light catalytic cracking gasoline fractions, and the characteristics of feedstocks I and II are shown in Tables 1 and 2, respectively.

[0084]

Table 1

[0085] Characteristics of Feedstock I

[0086]

Table 2

[0087] Characteristics of Feedstock II The catalytic conversion catalyst M used in the following examples and comparative examples was prepared by the following method: (1) Dissolve NH4Cl (20 g) in 1000 g of water. Add 100 g (dry weight) of crystalline ZRP-1 molecular sieve (manufactured by the catalyst plant of Qilu Petrochemical Technology, SiO2 / Al2O3 = 30, rare earth content RE2O3 = 2.0 wt%), and exchange at 90 °C for 0.5 h, then filter to obtain a filter cake; add 4.0 g of H3PO4 (concentration 85%) and 4.5 g of Fe(NO3)3 to 90 g of water, dissolve, mix with the impregnation filter cake, and then dry; then calcine at a temperature of 550 °C for 2 h to obtain an MFI mesoporous molecular sieve containing phosphorus and iron. The obtained molecular sieve has the following chemical composition determined by elemental analysis: 0.1Na2O·5.1Al2O3·2.4P2O5·1.5Fe2O3·3.8RE2O3·88.1SiO2.

[0088] (2) Slurry 75.4 kg of halloysite (industrial product of Suzhou Porcelain Clay, solid content 71.6 wt%) with 250 kg of deionized water, add 54.8 kg of pseudo-boehmite (industrial product of CHALCO Shandong, solid content 63 wt%) thereto, adjust the pH to 2 - 4 with hydrochloric acid, stir uniformly, let stand at 60 - 70 °C for 1 h for aging, keep the pH at 2 - 4, cool to 60 °C or below, and add 41.5 kg of alumina sol (product of the catalyst plant of Qilu Petrochemical Technology, Al2O3 content 21.7 wt%) thereto, and stir for 40 min to obtain a mixed slurry.

[0089] (3) Add the MFI mesoporous molecular sieve containing phosphorus and iron (dry weight 2 kg) prepared in step (1) to the mixed slurry obtained in step (2), stir uniformly, form by spray drying, wash with ammonium dihydrogen phosphate solution (phosphorus content 1 wt%), and wash to remove free Na +It was removed and dried to obtain a sample of the contact conversion catalyst M. Based on the total dry weight of the catalyst M, the composition of the catalyst M on a dry basis includes the following: 2% by weight of MFI mesoporous molecular sieve containing phosphorus and iron, 36% by weight of pseudoboehmite, 8% by weight of alumina sol, and the balance is kaolin.

[0090] [Example 1] According to the scheme shown in Figure 1, experiments were conducted in a pilot plant of a single fluidized bed reactor as follows: The 1-pentene feedstock was introduced at the bottom of the fluidized bed reactor, and the preheated catalyst M (720 °C) was introduced at the bottom of the fluidized bed reactor. The 1-pentene feedstock was brought into contact with the preheated catalyst M (720 °C), and the reaction was carried out under contact reaction conditions including a reaction temperature of 680 °C, a reaction pressure of 0.1 MPa, a reaction time of 10 seconds, and a weight ratio of catalyst M to 1-pentene feedstock of 30:1; The reaction product was separated from the carbon-deposited used catalyst M at the upper end of the fluidized bed reactor. The used catalyst was sent to a regenerator for regeneration by coke combustion. The regenerated catalyst was preheated to 720 °C and then recycled to the fluidized bed reactor.

[0091] The reaction product was separated in a product rectification column according to the distillation range to obtain products such as a stream containing ethylene, propylene, butylene, and residual olefins (C5+ olefins); thereafter, the stream containing residual olefins was sent to an olefin separator. The separated stream having an olefin content of 80% by weight and containing C5+ olefins was preheated to 680 °C and then introduced at the bottom of the fluidized bed reactor for further reaction. The reaction conditions and product distribution are listed in Table 3.

[0092] [Comparative Example 1-a] Experiments were conducted as described in Example 1 except that the 1-pentene feedstock was changed to 1-pentane. The product distribution is shown in Table 3.

[0093] [Comparative Example 1-b] The 1-pentane feedstock was subjected to a pyrolysis reaction under conditions including a reaction temperature of 800 °C, a reaction time of 0.2 seconds, and a weight ratio of steam to feedstock of 0.8 on a pilot plant of a single-tube pyrolysis reactor. The resulting reaction product was sent to a separation system for separation to obtain products such as ethylene, propylene, butylene, and an olefin-containing stream. The product distribution is shown in Table 3.

[0094] [Example 2] The experiment was conducted as described in Example 1, except that the 1-pentene feedstock was changed to a mixture of C5-C8 olefins, and the molar ratio of C5, C6, C7, and C8 olefins in the olefin mixture was 1:1:1:1. The product distribution is shown in Table 3.

[0095] [Comparative Example 2] The experiment was conducted as described in Example 1, except that the 1-pentene feedstock was changed to a mixture of C5-C8 alkanes, and the molar ratio of C5, C6, C7, and C8 alkanes in the alkane mixture was 1:1:1:1. The product distribution is shown in Table 3.

[0096] [Example 3] The experiment was conducted as described in Example 1, except that the 1-pentene feedstock was changed to Feedstock I. The product distribution is shown in Table 3.

[0097] [Example 4] The experiment was conducted as described in Example 1, except that the 1-pentene feedstock was changed to Feedstock II. The product distribution is shown in Table 3.

[0098] [Example 5] The experiment was conducted as described in Example 1, except that the temperature of the regenerated catalyst was raised to 800 °C and the reaction temperature was raised to 750 °C. The product distribution is shown in Table 3.

[0099] [Example 6] The experiment was conducted as described in Example 1, except that the temperature of the regenerated catalyst was lowered to 650 °C and the reaction temperature was lowered to 600 °C. The product distribution is shown in Table 3.

[0100] [Comparative Example 3] An experiment was conducted as described in Example 1, except that the temperature of the regeneration catalyst was lowered to 600 °C and the reaction temperature was lowered to 530 °C. The product distribution is shown in Table 3.

[0101] [Example 7] An experiment was conducted on a pilot plant of a riser reactor according to the scheme shown in Figure 2 as follows: A 1-pentene feedstock was fed to the bottom of the riser reactor and contacted with a catalytic conversion catalyst M preheated to 750 °C to carry out a catalytic conversion reaction under conditions including a temperature of 700 °C, a reaction pressure of 0.1 MPa, a reaction time of 5 seconds, and a weight ratio of the catalytic conversion catalyst to the feedstock of 30:1.

[0102] The reaction product vapor was separated from the used catalyst deposited with carbon, and the reaction product was divided in a product rectification column according to the distillation range to obtain products such as a stream containing ethylene, propylene, butylene, and residual olefins (having a distillation range of 20 - 250 °C). The stream containing residual olefins was further separated in an olefin separator to obtain a stream containing C5+ olefins and having an olefin content of 80% by weight.

[0103] The product butylene was fed to the bottom of the riser reactor for decomposition under conditions including a reaction temperature of 740 °C, a weight ratio of the catalytic conversion catalyst to butylene of 100:1, and a reaction time of 0.2 seconds. For further decomposition carried out at a reaction temperature of 700 °C for 5 seconds, the C5+ olefin-containing stream was fed to the bottom of the riser reactor downstream of the butylene feed position together with the 1-pentene feedstock. The product distribution is shown in Table 3.

[0104] [Example 8] The experiment was carried out on a pilot plant of a riser reactor according to the scheme shown in Figure 3. The operation and reaction conditions were as follows: methanol was introduced into the middle of the riser reactor, and the reaction was carried out under the conditions of a reaction temperature of 500 °C, a reaction time of 3 seconds, and a weight ratio of the catalytic conversion catalyst to methanol of 35:1; the butylene product was fed to the bottom of the riser reactor for separation under conditions including a reaction temperature of 740 °C, a weight ratio of the catalytic conversion catalyst to butylene of 100:1, and a reaction time of 0.2 seconds, etc., as described in Example 7. The product distribution is shown in Table 3.

[0105]

Table 3

[0106] As can be seen from Table 3, the decomposition of the olefin-containing feedstock at high temperatures in Examples 1 to 4 provided higher yields of ethylene, propylene, and butylene, and the higher the olefin content of the feedstock, the higher the yield. For example, in Example 1, when 1-pentene with an olefin content of 100% was used as the feedstock, the ethylene content in the product was 23.30%, the propylene content was 34.22%, the butylene content was 17.44%, and the total content of the three was 74.96%. Example 7 used a higher reaction temperature and butylene recycle, thereby providing an ethylene yield of 34.33%, a propylene yield of 39.12%, and a yield of two olefins of 73.45%. When the reaction temperature was lowered to 600 °C or less as in Comparative Example 3, the yields of both ethylene and propylene decreased significantly. When the supply amount of the oxygen-containing organic compound was increased as in Example 8, the yields of the two olefins (ethylene and propylene) increased by 2.78 percentage points compared to Example 7. Furthermore, the yields of benzene, toluene, and xylene for olefin separation in each example of the present application also increased significantly compared to the alkane separation in Comparative Examples 1-a and 2.

[0107] Although the present application has been described in detail above with reference to preferred embodiments, it is not intended to be limited to these embodiments. Various modifications can be made in accordance with the inventive concept of the present application, and these modifications are within the scope of the present application.

[0108] In addition, the various technical features described in the above embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, various possible combinations are not described in the present application, but such combinations are also considered to be included within the scope of the present application.

[0109] Also, each embodiment of the present application can be arbitrarily combined within the scope not departing from the gist of the present application, and the combined embodiments are regarded as the disclosure content of the present application.

Brief Description of the Drawings

[0110]

Figure 1

Figure 2

Figure 3

Claims

1. A fluidized catalytic conversion method for producing light olefins, the method comprising the following steps: 1) A step of introducing an olefin-rich feedstock into a fluidized catalytic conversion reactor and contacting it with a catalytic conversion catalyst having a temperature of 650 °C or higher, and reacting it under a first catalytic conversion condition, wherein the olefin-rich feedstock has an olefin content of 50% by weight or more, and the olefins in the olefin-rich feedstock consist essentially of C5+ olefins; 2) Separating the effluent of the fluidized catalytic conversion reactor to obtain reaction product vapor and spent catalyst, and separating the reaction product vapor to obtain a stream containing ethylene, propylene, butylene and C5+ olefins; 3) A step of recycling at least a part of the C5+ olefin-containing stream to step 1) for further reaction; The first catalytic conversion conditions are: A reaction temperature of 600-800 °C; A reaction pressure of 0.05-1 MPa; A reaction time of 0.01-100 seconds; A weight ratio of the catalytic conversion catalyst to the olefin-rich feedstock of (1-200):1; and 4) A step of recycling at least a part of the butylene separated in step 2) upstream of the catalytic conversion reactor, which is the position where the olefin-rich feedstock is introduced into contact with the catalytic conversion catalyst, and reacting it under a second catalytic conversion condition: The second catalytic conversion conditions are: A reaction temperature of 650-800 °C; A reaction pressure of 0.05-1 MPa; A reaction time of 0.01-10 seconds; A weight ratio of the catalytic conversion catalyst to the butylene of (20-200):

1.

2. The method according to claim 1, wherein the olefin-rich feedstock has an olefin content of 80% by weight or more.

3. The method according to claim 2, wherein the olefin-rich feedstock is a pure olefin feedstock.

4. The olefin-rich feedstock is one or more of a C5+ fraction produced by an alkane dehydrogenation unit, a C5+ fraction produced by a catalytic cracking unit in an oil refinery, a C5+ fraction produced by a steam cracking unit in an ethylene plant, a C5+ olefin-rich by-product fraction of an MTO process, and a C5+ olefin-rich by-product fraction of an MTP process. The method according to any one of claims 1 to 3.

5. The first catalytic conversion conditions are: A reaction temperature of 630-780 °C; A reaction pressure of 0.1 to 0.8 MPa; A reaction time of 0.1 to 80 seconds; A method according to any one of claims 1 to 4, comprising a weight ratio of the catalytic conversion catalyst to the olefin-rich feedstock of (3 to 180):

1. **Claim 6** The second catalytic conversion conditions are: A reaction temperature of 680 to 780 °C; A reaction pressure of 0.1 to 0.8 MPa; A reaction time of 0.05 to 8 seconds; A method according to any one of claims 1 to 5, comprising a weight ratio of the catalytic conversion catalyst to the butylene of (30 to 180):

1. **Claim 7** A method according to any one of claims 1 to 6, further comprising the following steps: 1a) Introducing an oxygen-containing organic compound downstream of the catalytic conversion reactor and reacting under third catalytic conversion conditions, wherein downstream of the catalytic conversion reactor is the position where the olefin-rich feedstock is introduced to contact the catalytic conversion catalyst after the reaction of step 1): The third catalytic conversion conditions are: A reaction temperature of 300 to 550 °C; A reaction pressure of 0.01 to 1 MPa; A reaction time of 0.01 to 100 seconds; A step comprising a weight ratio of the catalytic conversion catalyst to the oxygen-containing organic compound feedstock of (1 to 100):

1. **Claim 8** The third catalytic conversion conditions are: A reaction temperature of 400 to 530 °C; A reaction pressure of 0.05 to 1 MPa; A reaction time of 0.1 to 80 seconds; Comprising a weight ratio of the catalytic conversion catalyst to the oxygen-containing organic compound feedstock of (3 to 50):1, The oxygen-containing organic compound comprises at least one of methanol, ethanol, dimethyl ether, methyl ethyl ether and ethyl ether, the method according to claim 7. **Claim 9** The catalytic conversion catalyst comprises 1 to 50 wt% of molecular sieve, 5 to 99 wt% of inorganic oxide, and 0 to 70 wt% of clay based on the weight of the catalytic conversion catalyst, The molecular sieve comprises 50 to 100 wt% of mesoporous molecular sieve and 0 to 50 wt% of microporous molecular sieve based on the total weight of the molecular sieve; The mesoporous molecular sieve is a ZSM molecular sieve and the microporous molecular sieve is a SAPO molecular sieve, the method according to any one of claims 1 to 8. **Claim 10** The catalytic reforming catalyst contains 0.1 to 3% by weight of a modifying element based on the weight of the catalytic reforming catalyst; the modifying element is one or more selected from the group consisting of Group VIII metals, Group IVA metals, Group VA metals, and rare earth metals. The method according to any one of claims 1 to 9.

11. The fluidized catalytic reforming reactor is one selected from the group consisting of a riser reactor, an isokinetic fluidized bed, an isothermal fluidized bed, an upward transfer line, and a downward transfer line, or a combined reactor of two of them connected in series. The riser reactor is an equal-diameter riser reactor or a diameter-converting fluidized bed reactor. The method according to any one of claims 1 to 10.

12. The method according to any one of claims 1 to 11, further comprising the following steps: 5) Regenerating the used catalyst obtained by the separation in step 2) by coke combustion to obtain a regenerated catalyst, adjusting the temperature of the regenerated catalyst to 650 °C or higher, and then recycling the regenerated catalyst to the fluidized catalytic reforming reactor for use as the catalytic reforming catalyst.

13. The C5+ olefin-containing stream has a C5+ olefin content of 50% by weight or more. The method according to any one of claims 1 to 12.

14. The method according to any one of claims 1 to 13, wherein step 2) includes the following steps: 2a) Separating the effluent from the fluidized catalytic reforming reactor to obtain a reaction product vapor and the used catalyst; 2b) Separating the reaction product vapor in a product rectification column to obtain an ethylene, propylene, butylene, and first olefin-containing stream; and 2c) Separating the first olefin-containing stream in an olefin separator to obtain a C5+ olefin-containing stream, wherein the olefin content in the C5+ olefin-containing stream is higher than the olefin content in the first olefin-containing stream.

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