Catalytic conversion method for preparing light olefins

Abstract

A catalytic conversion method for preparing light olefins. The method comprises the following steps: in a bed layer of a dense-phase fluidized bed, of which the catalyst density of a first catalytic conversion reactor (A) is 100-700 kg / m3, bringing a hydrocarbon raw material into contact with a first catalyst, and carrying out a catalytic conversion reaction at a reaction temperature of 550-800°C, to obtain a first reaction oil-gas containing light olefins and a first reaction material flow containing a first spent catalyst, then cooling the first reaction material flow to 450-530°C in a cooling zone (34), and taking out the catalyst from the bed layer of the dense-phase fluidized bed by means of a slide valve (7), so as to keep the catalyst density of the bed layer of the dense-phase fluidized bed at a set value, and separating the first reaction oil-gas containing the light olefins to obtain the light olefins. The reaction material flow is cooled in the cooling zone (34), and the catalyst is taken out by means of the slide valve (7), such that on the one hand, the energy consumption of the cooling zone (34) can be reduced, and on the other hand, the thermal cracking reaction can be obviously inhibited, thereby reducing the byproduct yield while increasing the yield of the light olefins.

Description

Catalytic conversion method for producing light olefins Technical Field

[0001] The present invention belongs to the field of petroleum processing, and in particular relates to a catalytic conversion method for producing light olefins and a system for implementing the method. Background Art

[0002] Low-carbon olefins are important basic organic chemical raw materials and are widely used in various fields. For example, ethylene is mainly used to produce polyethylene, ethylene oxide, polyvinyl chloride and other materials. Propylene can be used to produce acrylonitrile, propylene oxide, acetone and other chemical products. Butene can be used to produce butadiene, butene polymers and other organic materials.

[0003] The typical process for producing light olefins at present is naphtha steam cracking, and the productive rate of its ethene and propylene is lower, and is difficult to meet the market demand that increases day by day. To this, CN1490287A discloses a method for producing light olefins as raw material by adopting a hydrocarbon mixture containing C4 or C5 monoolefins, wherein the hydrocarbon mixed stock contacts with a catalyst in a fixed-bed reactor and reacts, but the ethene and propylene productive rates are lower in the product obtained. CN114763483A discloses a method for producing light olefins by adopting a hydrocarbon raw material, wherein the hydrocarbon oil raw material containing olefins is first subjected to pyrolysis, and then the olefins in the separated product are introduced into a catalytic conversion reactor and continue to react, so as to fully utilize butenes and C5 or higher olefins to produce ethene and propylene, and reduce the methane yield.

[0004] Although the yield of light olefins in the existing methods of producing light olefins from olefin raw materials has been greatly improved, thermal cracking and secondary reactions of the products are still relatively common, the ethylene and propylene contents in the products are low, the ethylene / propylene ratio is low, and there is a problem of excessive energy consumption.

[0005] Summary of the Invention

[0006] The object of the present invention is to provide a method for improving the yield of light olefins, which can increase the ethylene / propylene ratio in the light olefins and reduce the energy consumption of the reaction system.

[0007] In order to achieve the above object, the present invention provides a catalytic conversion method for producing light olefins, which comprises the following steps:

[0008] In a dense phase fluidized bed layer of a first catalytic conversion reactor, the catalyst density is set to a set value, and a hydrocarbon feedstock is brought into contact with a first catalyst and a catalytic conversion reaction occurs. The reaction temperature is 550-800° C. to obtain a first reaction stream containing a first reaction oil gas containing light olefins and a first spent catalyst. The first reaction stream is then cooled to 450-530° C. in a cooling zone. The set value of the catalyst density is selected from 100-700 kg / m3 between;

[0009] The catalyst is taken out from the dense phase fluidized bed through the slide valve to keep the catalyst density in the dense phase fluidized bed at the set value.

[0010] Separating the first reaction oil and gas containing light olefins to obtain light olefins,

[0011] Among them, a cooling zone is set at a position where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense fluidized bed layer, and preferably a cooling zone is set at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense fluidized bed layer, to cool the first reaction flow.

[0012] In the present invention, the first catalytic conversion reactor comprises, from bottom to top, a first lifting section, an expanding section, a dense phase fluidized bed section, a cooling zone, a reducing section, and a second lifting section;

[0013] The angle between the side wall of the expanded diameter section and the axis is 5-60 degrees;

[0014] The ratio of the diameter to the height of the dense phase fluidization section is (1-20):1;

[0015] The angle between the side wall of the reduced diameter section and the axis is 5-60 degrees;

[0016] The head of the first lifting section is provided with a first catalyst inlet and a lifting medium inlet;

[0017] A raw material inlet is provided in the middle of the first lifting section;

[0018] A gas-solid mixed fluid distributor is also provided at the tail of the first lifting section;

[0019] The cooling zone is arranged downstream of the dense phase fluidization section, and is arranged at any position within the region where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense phase fluidized bed layer, preferably at any position within the region where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense phase fluidized bed layer.

[0020] The slide valve is arranged in the diameter expansion section.

[0021] The method of the present invention may further comprise the following steps:

[0022] The heavy hydrocarbon oil is brought into contact with a second catalyst in a second catalytic conversion reactor to perform a second catalytic conversion reaction, thereby obtaining a second reaction stream comprising a second reaction oil gas containing light oil and a second spent catalyst;

[0023] Mixing the second reactant stream with the first reactant stream, and performing a first separation on the mixed stream to obtain a mixed reactant stream containing light olefins and a mixed spent catalyst;

[0024] The mixed reaction stream containing light olefins is fractionated to separate dry gas, light olefins and C5 and above distillates, the C5 and above distillates are subjected to a second separation and the separated hydrocarbon components are returned to the first catalytic conversion reactor as a hydrocarbon feedstock; and the mixed spent catalyst is charred and regenerated, and the regenerated catalyst is returned to the first catalytic conversion reactor as a first regenerated catalyst and to the second catalytic conversion reactor as a second regenerated catalyst.

[0025] Preferably, the second catalyst comprises a reacted catalyst removed from the slide valve of the first catalytic conversion reactor. More preferably, part or all of the second catalyst comprises a reacted catalyst removed from the slide valve of the first catalytic conversion reactor.

[0026] The present invention also provides a system for producing light olefins from hydrocarbon feedstock, characterized in that the system comprises a first catalytic conversion reactor,

[0027] The first catalytic conversion reactor comprises, from bottom to top, a first lifting section, an expanding section, a dense phase fluidized bed section, a cooling zone, a reducing section, a second lifting section and a top outlet;

[0028] The angle between the side wall of the expanded diameter section and the axis is 5-60 degrees;

[0029] The ratio of the diameter to the height of the dense phase fluidized bed section is (1-20):1;

[0030] The angle between the side wall of the reduced diameter section and the axis is 5-60 degrees;

[0031] The head of the first lifting section is provided with a catalyst inlet and a lifting medium inlet;

[0032] A raw material inlet is provided in the middle of the first lifting section;

[0033] A gas-solid mixed fluid distributor is also provided at the tail of the first lifting section;

[0034] The cooling zone is arranged downstream of the dense phase fluidized bed section, and is arranged at a position where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense phase fluidized bed section, preferably at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense phase fluidized bed section.

[0035] The slide valve is arranged in the expanded diameter section.

[0036] Through the above technical solution, the present invention has the following beneficial effects:

[0037] (1) The present invention optimizes the control of catalytic cracking and thermal cracking reactions by rapidly cooling the stream after the catalytic conversion reaction in the cooling zone, effectively inhibiting the thermal cracking reaction during the reaction, reducing the generation of by-products such as methane, and improving the yield and selectivity of light olefins;

[0038] (2) In the method of the present invention, the catalyst storage in the dense phase fluidized bed is adjusted by a slide valve, so that the catalyst density is adjustable and controllable, and the relative position between the cooling zone and the dense phase fluidized bed is adjustable and controllable, thereby enabling real-time regulation of the catalytic conversion reaction;

[0039] (3) In the method of the present invention, the stream after the catalytic reaction is cooled at a specific location, which can effectively suppress the thermal cracking reaction during the reaction process without excessively reducing the conversion rate of the catalytic conversion reaction in the reaction zone, reduce the formation of by-products such as methane, and thus improve the yield and selectivity of light olefins. In addition, the spent catalyst is removed through the slide valve, which can reduce the energy consumption of the cooling zone and adjust the catalyst density.

[0040] (4) In the method of the present invention, the hydrocarbon feedstock catalytic conversion process of the present invention and the heavy oil catalytic cracking process can be coupled, thereby being used to produce a variety of target products, and the respective advantages of the processes for producing light olefins from different feedstocks can be brought into play, thereby increasing the yield and selectivity of light olefins and improving the utilization rate of petroleum resources. Moreover, when coupled with the heavy oil catalytic cracking process, the catalyst removed from the slide valve of the first catalytic conversion reactor can be used as a catalyst for the heavy oil catalytic cracking reaction, thereby further reducing the energy consumption of the entire reaction process.

[0041] (5) In the device of the present invention, by providing a cooling zone at an appropriate downstream position in the catalytic conversion reactor, the reaction flow after catalytic conversion can be rapidly cooled. Thus, without excessively reducing the conversion rate of the catalytic conversion reaction in the reaction zone, unnecessary thermal cracking reactions in the reaction flow are suppressed, and the generation of by-products such as methane is reduced, thereby improving the yield and selectivity of light olefins.

[0042] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0044] FIG1 is a schematic diagram of an embodiment of the first reactor provided by the present invention.

[0045] FIG2 is a schematic diagram of another embodiment of the first reactor provided by the present invention.

[0046] FIG3 is a schematic diagram of another embodiment of the first reactor provided by the present invention.

[0047] FIG4 is a schematic diagram of an embodiment of the method provided by the present invention.

[0048] FIG5 is a schematic diagram of another embodiment of the method provided by the present invention.

[0049] FIG6 is a schematic diagram of an embodiment of the catalytic conversion method provided by the present invention.

[0050] FIG7 is a schematic diagram of another embodiment of the catalytic conversion method provided by the present invention.

[0051] Description of Reference Numerals

[0052] A first reactor B second reactor

[0053] 1 pipeline 2 pipeline 3 material distributor

[0054] 4 pipelines 5 pipelines 6 pipelines

[0055] 7 slide valve 8 pipeline 9 stripping section

[0056] 10 Second lifting section 11 Horizontal pipe 12 Settler

[0057] 13 cyclone separator 14 air collecting chamber 15 waiting inclined pipe

[0058] 16 regenerator 17 pipeline 18 pipeline

[0059] 19 pipeline 20 large oil and gas pipeline 21 distillation tower

[0060] Pipeline 22 Pipeline 23 Pipeline 24

[0061] Pipeline 25, Pipeline 26, Pipeline 27

[0062] 28 pipeline 29 pipeline 30 alkane olefin separation unit

[0063] Pipeline 31, 32, and 33, first lifting section

[0064] 34 cooling zone 35 cooling medium distributor 36 pipeline

[0065] 37 pipeline 38 pipeline 39 heat exchanger DETAILED DESCRIPTION

[0066] Hereinafter, specific embodiments of the present invention will be described in detail. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the appended claims.

[0067] In the context of this specification, except for the contents explicitly stated, any matters or issues not mentioned are directly applicable to those known in the art without any changes. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or technical ideas formed thereby are considered part of the original disclosure or original description of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless a person skilled in the art considers that the combination is obviously unreasonable.

[0068] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight, unless the weight basis does not conform to the general understanding of those skilled in the art.

[0069] The specific embodiments of the present invention are described in detail below. However, it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0070] In the context of the present invention, unless otherwise specified, the physical properties of a substance (such as boiling point) are all measured values ​​at normal temperature (25° C.) and normal pressure (101325 Pa).

[0071] After in-depth research, the inventors of the present invention found that by contacting the hydrocarbon feedstock with the catalyst in a high-density dense fluidized bed and rapidly cooling the post-reaction logistics at an appropriate location, the generation of dry gas (mainly methane) in the product can be effectively suppressed, and the proportion of light olefins in the product can be increased; on the other hand, by maintaining the dense fluidized bed at a specific temperature, the occurrence of bimolecular cracking reactions can be effectively suppressed, and the production of high-carbon olefins can be suppressed, thereby increasing the proportion of light olefins in the product.

[0072] Furthermore, the inventors of the present invention removed the catalyst from the dense-phase fluidized bed via a slide valve and used it for regeneration or returned it to the first catalytic conversion reaction, thereby improving catalyst utilization and reducing reaction energy consumption. Furthermore, the removed catalyst can be used for catalytic cracking of heavy hydrocarbon oil, further reducing reaction energy consumption and improving reaction efficiency.

[0073] The present invention provides a catalytic conversion method for producing light olefins, which comprises the following steps:

[0074] In a dense phase fluidized bed layer of a first catalytic conversion reactor (hereinafter sometimes referred to as the first reactor) having a catalyst density of a set value, a hydrocarbon feedstock is brought into contact with a first catalyst (hereinafter sometimes referred to as the catalyst) and a catalytic conversion reaction occurs. The reaction temperature is 550-800° C. to obtain a first reaction stream comprising a first reaction oil gas containing light olefins and a first spent catalyst. The first reaction stream is then cooled to 450-530° C. in a cooling zone. The set value of the catalyst density is selected from 100-700 kg / m 3 between;

[0075] The catalyst is taken out from the dense phase fluidized bed through the slide valve to keep the catalyst density in the dense phase fluidized bed at the set value.

[0076] Separating the first reaction oil and gas containing light olefins to obtain light olefins,

[0077] Among them, a cooling zone is set at a position where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense fluidized bed layer, and preferably a cooling zone is set at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense fluidized bed layer, to cool the first reactant flow (in the present invention, also referred to as the reactant flow or reactant flow after the reaction) .

[0078] In the present invention, by cooling the logistics after the catalytic conversion reaction in a cooling zone at a specific position, the control of the catalytic cracking reaction and the thermal cracking reaction is optimized, the thermal cracking reaction during the reaction process can be effectively suppressed, and the yield and selectivity of light olefins can be improved.

[0079] The inventors have discovered that by providing a cooling zone at a specific location to cool the reactant flow immediately after the catalytic conversion reaction, the thermal cracking reaction during the reaction process can be effectively suppressed, thereby improving the yield and selectivity of light olefins. Specifically, after in-depth research, the inventors have discovered that when the cooling zone is located too upstream of the catalytic conversion reaction zone, the cooling zone may intrude into the catalytic conversion reaction zone, affecting the temperature of the conversion reaction, resulting in the formation of large molecular olefin products, and affecting the selectivity and yield of the ethylene product. On the other hand, when the cooling zone is located too downstream of the catalytic conversion reaction zone, the reactant flow in the catalyst dilute phase zone is at a high temperature, but is not in sufficient contact with the catalyst, resulting in insufficient suppression of the thermal cracking reaction, thereby affecting the yield and selectivity of light olefins.

[0080] The inventors of the present invention have conducted in-depth research and exploration on this issue and found that in the first catalytic conversion reactor, when the catalyst density is 100-700 kg / m 3 Downstream of the dense fluidized bed, a cooling zone is provided at a position where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense fluidized bed, preferably to 70% to 30% of the catalyst density in the dense fluidized bed, to cool the post-reaction stream (this cooling step is sometimes also referred to as a cooling step in the present invention). This effectively suppresses thermal cracking reactions in the reactant stream after the catalytic conversion reaction, thereby improving the yield and selectivity of light olefins.

[0081] In other words, in the present invention, the first catalytic conversion reactor includes a catalyst with a density of 100-700 kg / m 3 A cooling zone is set in the bed layer of the dense fluidized bed along the downstream position of the dense fluidized bed in the direction of the reactant flow, where the catalyst density is reduced to 80%-20% of the catalyst density in the bed layer of the dense fluidized bed, preferably to 70%-30% of the catalyst density in the bed layer of the dense fluidized bed, to cool the flow from the dense fluidized bed after the catalytic conversion reaction to 450-530°C, preferably to 480-500°C.

[0082] In the present invention, a cooling zone is set at a position where the catalyst density drops to a specific range. The reactant flow after the reaction enters the cooling zone for cooling. After being cooled to 450-530°C, the reactant flow basically no longer undergoes catalytic conversion reaction.

[0083] Therefore, in the present invention, "providing a cooling zone at a location where the catalyst density drops to a specific range" means providing a cooling zone at any location within the region where the catalyst density drops to a specific range, rather than defining that region as the cooling zone. In fact, in the present invention, there is no intended limitation on the length of the cooling zone in the direction of reactant flow; as long as the temperature can be rapidly reduced (e.g., within 0.5-2 seconds, or within 0.5-1 second) to cool the reacted stream to 450-530°C, preferably 480-500°C, it will suffice.

[0084] As used herein, a "dense-phase fluidized bed" refers to the catalyst reservoir region within a catalytic converter reactor. A lifting medium is used to concentrate the catalyst in this region. The position of this bed can be varied by varying the lifting medium flow rate, the reactant flow rate, the amount of catalyst, and the like. Based on common knowledge in the art, a person skilled in the art can readily identify a dense-phase fluidized bed.

[0085] In the present invention, "catalyst density in a dense fluidized bed" refers to the catalyst density in the catalyst inventory region of a catalytic conversion reactor. In this catalyst inventory region, the feed of catalyst and / or regenerated catalyst is balanced with the discharge of regenerated catalyst entrained in the post-reaction stream, and the catalyst inventory remains substantially constant. Therefore, the catalyst density in the dense fluidized bed remains substantially constant. Those skilled in the art can adjust the catalyst density in the dense fluidized bed as needed by means known in the art. For example, the catalyst density in the dense fluidized bed can be adjusted based on the amount of catalyst used, the flow rate of the lifting medium, the diameter / height ratio of the fluidized bed section, etc.

[0086] In the present invention, the catalyst density in the dense-phase fluidized bed, specifically the catalyst density in the catalyst reservoir region, can be controlled by a slide valve. This allows the catalyst density in the dense-phase fluidized bed to be rapidly varied according to a set value. This also allows the relative position of the dense-phase fluidized bed and the cooling zone to be controlled, thereby adjusting the conversion rate and selectivity of the catalytic conversion reaction.

[0087] In the present invention, the light olefin is at least one of ethylene, propylene, and butene. The first reaction oil gas containing light olefins in the present invention generally contains a mixture of ethylene, propylene, and butene.

[0088] In the present invention, the catalyst density of the first catalytic conversion reactor is selected from 100-700 kg / m 3 The set value between 100-700 kg / m 3In the catalytic conversion reaction of the present invention, the reaction is carried out under the catalyst density of the set value. Therefore, in the present invention, it can also be said that the catalyst density of the dense phase fluidized bed is 100-700 kg / m 3 , indicating that the catalyst density is selected from 100-700 kg / m 3 A value between .

[0089] In the present invention, catalyst is removed from the dense-phase fluidized bed via a slide valve to maintain the catalyst density within the dense-phase fluidized bed at a set value. This not only improves the cooling efficiency of the cooling zone and reduces reaction energy consumption, but also allows the removed catalyst, which remains at a high temperature without cooling, to be returned to the first catalytic conversion reactor or fed to the second catalytic conversion reactor.

[0090] It should be noted that in the present invention, catalyst is removed from the bottom of the dense-phase fluidized bed via a slide valve. Therefore, the catalyst removed should be spent catalyst that has at least partially participated in the catalytic conversion reaction. The present invention does not intend to limit the state of the catalyst removed from the slide valve. As long as the catalyst density in the dense-phase fluidized bed reaches a set value after the catalyst is removed via the slide valve, it is sufficient. In the present invention, the catalyst removed from the slide valve is sometimes referred to as spent catalyst.

[0091] In one embodiment of the present invention, at least a portion of the spent catalyst is taken out from the first reactant stream comprising the first reaction oil gas containing light olefins and the first spent catalyst through a slide valve.

[0092] In one embodiment of the present invention, the catalyst taken out through the slide valve is optionally stripped and then introduced into a regenerator for regeneration.

[0093] In one embodiment of the present invention, the catalyst taken out through the slide valve is returned to the catalyst inlet of the first catalytic conversion reactor, mixed with the first catalyst, and then enters the reaction zone of the first catalytic conversion reactor again.

[0094] In one embodiment of the present invention, the catalyst taken out through the slide valve is used for a second catalytic conversion reaction.

[0095] In the method for producing light olefins from hydrocarbon feedstocks of the present invention, the temperature reduction performed in the cooling zone is also referred to as a cooling step.

[0096] In the cooling step of the present invention, there is no limitation on the means for cooling the temperature, and means known in the art may be used, such as cooling the temperature using a heat exchanger, cooling the temperature by introducing a cooling medium, etc.

[0097] In one embodiment of the present invention, in the cooling step, the temperature is lowered by using a cooling medium distributor.

[0098] In one embodiment of the present invention, in the cooling step, a heat extractor is used for cooling.

[0099] In one embodiment of the present invention, in the cooling step, the cooling medium in the cooling medium distributor or the heat extractor is at least one selected from liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel and water.

[0100] In one embodiment of the present invention, in the cooling zone, the cooling medium distributor is arranged in a ring shape along the circumference of the catalytic conversion reactor, and the cooling step is implemented through the cooling medium distributor.

[0101] In one embodiment of the present invention, in the cooling zone, a heat exchanger is provided in an annular shape along the circumference of the catalytic conversion reactor, and the cooling step is performed by the heat exchanger.

[0102] As a cooling method using a cooling medium distributor, physical cooling by spraying cooling medium can be used, or the above-mentioned cooling medium can be used as a second raw material to undergo cracking reaction in the cooling zone to absorb heat, so as to quickly cool the post-reaction logistics.

[0103] In the present invention, a cooling step is implemented in a cooling zone at a specific position of the first catalytic conversion reactor to rapidly cool the logistics after the catalytic conversion reaction to a target temperature (450-530°C, preferably 480-500°C) in a short period of time, so as to effectively suppress the thermal cracking reaction in the reaction logistics after the catalytic conversion reaction and improve the yield and selectivity of light olefins.

[0104] In the present invention, a cooling zone is provided at a position where the catalyst density drops to 80% to 20% of the catalyst density in the dense fluidized bed (i.e., the set value density), preferably at a position where the catalyst density drops to 70% to 30% of the catalyst density in the dense fluidized bed (i.e., the set value density), to cool the reactant stream after the reaction. Thus, cooling of the reactant stream after the reaction begins at a position where the catalyst density drops to 80% to 20% of the catalyst density in the dense fluidized bed, preferably at a position where the catalyst density drops to 70% to 30% of the catalyst density in the dense fluidized bed, allowing the stream to be cooled rapidly.

[0105] In one embodiment of the present invention, cooling zones are provided at positions where the catalyst density is reduced to 80%, 70%, 60%, 50%, 40%, 30%, or 20% of the catalyst density in the dense fluidized bed.

[0106] In one embodiment of the present invention, the reaction stream is cooled to 450-530°C, preferably 480-500°C, by the cooling zone of the first catalytic conversion reactor. In the present invention, if the temperature of the reaction stream after the cooling step in the cooling zone exceeds 530°C, possible thermal cracking reactions in the reaction stream are not fully suppressed, resulting in a decrease in the yield and selectivity of light olefins. If the temperature of the reaction stream after the cooling step in the cooling zone is lower than 450°C, the energy consumption of the cooling zone will be excessively increased, and the energy consumption required for subsequent catalyst regeneration will also increase.

[0107] In one embodiment of the present invention, in the cooling step in the cooling zone, the reacted logistics is cooled to the target temperature (450-530°C, preferably 480-500°C) within 0.5-2 seconds, preferably within 0.5-1 second.

[0108] In other words, the cooling step of the present invention must be performed rapidly. If the cooling time is too long, the cooling rate is insufficient, and possible thermal cracking reactions in the reactant stream are not fully suppressed, resulting in a decrease in the yield and selectivity of light olefins. On the other hand, if the cooling time is too short, an excessive amount of cooling medium or high-power heat extraction is required, resulting in unnecessary waste.

[0109] In one embodiment of the present invention, in the first catalytic conversion reactor, the catalyst density (i.e., set value density) of the catalyst in the dense phase fluidized bed is 100-700 kg / m 3 , preferably 300-650kg / m 3 , more preferably 500-650kg / m 3 If the density of the catalyst is too low, the contact between the reaction raw materials and the catalyst is insufficient, and thermal cracking reaction is likely to occur. On the other hand, if the density of the catalyst is too high, it may cause secondary conversion of the product, which is not conducive to the production of light olefins.

[0110] In one embodiment of the present invention, the conditions for the catalytic conversion reaction include: a reaction temperature of 550-800°C, preferably 580-750°C, and more preferably 600-700°C.

[0111] In one embodiment of the present invention, the reaction time of the catalytic conversion reaction is 0.05-10 seconds, preferably 0.1-5 seconds, and more preferably 0.2-2 seconds.

[0112] In one embodiment of the present invention, the reaction pressure of the catalytic conversion reaction is 0.01-1 MPa, preferably 0.1-0.8 MPa, and more preferably 0.2-0.5 MPa.

[0113] In one embodiment of the present invention, the weight ratio of the first catalyst to the hydrocarbon feedstock is (1-200):1, preferably (10-100):1, and more preferably (20-100):1.

[0114] In one embodiment of the present invention, the first catalyst is a regenerated catalyst, preferably a catalyst obtained by regenerating the first catalyst to be regenerated through a regenerator.

[0115] In the present invention, in the first catalytic conversion reactor, since the reactor is in the form of a riser reactor, the logistics in the reaction flow from bottom to top.

[0116] In one embodiment of the present invention, the first catalytic conversion reactor includes, from bottom to top, a first lifting section, an expansion section, a dense phase fluidized bed section, a cooling zone, a reduction section and a second lifting section.

[0117] In one embodiment of the present invention, the angle between the side wall of the expanded diameter section and the axis is 5-60 degrees.

[0118] In one embodiment of the present invention, the ratio of the diameter to the height of the dense phase fluidized bed section is (1-20):1.

[0119] In one embodiment of the present invention, the angle between the side wall of the reduced diameter section and the axis is 5-60 degrees.

[0120] In one embodiment of the present invention, a hot catalyst inlet and a lifting medium inlet are provided at the head of the first lifting section; and a raw material inlet is provided at the middle of the first lifting section.

[0121] In one embodiment of the present invention, a slide valve for removing the catalyst is provided on the side wall of the expanded diameter section.

[0122] In one embodiment of the present invention, a gas-solid mixed fluid distributor is further provided at the tail of the first lifting section.

[0123] In one embodiment of the present invention, the cooling zone is located downstream of the dense fluidized bed section and upstream of the diameter reduction section. Specifically, the cooling zone is located at any position within the region where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense fluidized bed layer, and preferably located at any position within the region where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense fluidized bed layer.

[0124] In one embodiment of the present invention, a slide valve is provided for removing spent catalyst from the dense phase fluidized bed section. Preferably, the slide valve is provided at the bottom of the dense phase fluidized bed section for removing the catalyst.

[0125] In one embodiment of the present invention, the end of the second lifting section is connected to a pipeline connected to a subsequent separation system. Through the pipeline, the first reaction oil gas containing light olefins and the first catalyst to be generated are transported to the separation system for gas-solid separation. The diameter of the pipeline can be determined according to the specific situation.

[0126] In one embodiment of the present invention, based on the total weight of the first catalyst, the first catalyst comprises 1-50 wt% of a molecular sieve, 5-99 wt% of an inorganic oxide, and 0-70 wt% of clay;

[0127] In one embodiment of the present invention, the molecular sieve is at least one selected from the group consisting of ZSM-5 series molecular sieves and SAPO series molecular sieves; preferably at least one selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, SAPO-34, SAPO-11 and SAPO-47.

[0128] In one embodiment of the present invention, the silicon to aluminum ratio of the molecular sieve is 10-1000.

[0129] In one embodiment of the present invention, the inorganic oxide is one or more selected from silicon dioxide and aluminum oxide.

[0130] In one embodiment of the present invention, the clay is one or more selected from kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

[0131] In one embodiment of the present invention, the hydrocarbon feedstock is a gaseous feed.

[0132] In one embodiment of the present invention, the hydrocarbon feedstock is preheated and then enters the first catalytic conversion reactor in a gaseous state for catalytic conversion reaction.

[0133] In one embodiment of the present invention, the hydrocarbon feedstock is a feedstock rich in olefins, particularly a feedstock rich in higher olefins having 5 or more carbon atoms.

[0134] In one embodiment of the present invention, the content of C5-C8 olefins in the hydrocarbon feedstock is 50-100 wt%, preferably 80-100 wt%, and more preferably 90-100 wt%.

[0135] In one embodiment of the present invention, the hydrocarbon feedstock is an olefin feedstock. In some specific embodiments of the present invention, the hydrocarbon feedstock is an olefin feedstock, for example, any one of 1-pentene, 1-hexene, 1-heptene and 1-octene, or a mixture of several of them.

[0136] In one embodiment of the present invention, the hydrocarbon feedstock is at least one selected from the group consisting of a C5 or higher fraction produced by an alkane dehydrogenation unit, a C5 or higher fraction produced by a catalytic cracking unit in a refinery, a C5 or higher fraction produced by a steam cracking unit in an ethylene plant, a C5 or higher olefin-rich fraction produced as a by-product of an MTO (methanol to light olefins process), and a C5 or higher olefin-rich fraction produced as a by-product of an MTP (methanol to propylene process).

[0137] In one embodiment of the present invention, when the hydrocarbon feedstock of the present invention is produced by alkane dehydrogenation, the alkane feedstock used is not particularly limited. For example, it can be at least one of naphtha, aromatic raffinate, and other light hydrocarbons. In addition, alkane products produced by other petrochemical plants can also be used as the feedstock.

[0138] In one embodiment of the present invention, the hydrocarbon feedstock is preheated and then enters the reaction zone of the first catalytic conversion reactor from the first rising section in a gaseous state for catalytic conversion reaction.

[0139] In the present invention, the method for separating the light olefins from the first reactant stream is not particularly limited and can be performed using methods known in the art. For example, the light olefins (at least one of ethylene, propylene, and butene) of the present invention can be obtained by performing gas-solid separation on the first reactant stream and performing conventional separation operations on the resulting first reaction oil gas containing light olefins.

[0140] More specifically, in one embodiment of the present invention, the method further includes the following steps: performing gas-solid separation on the first reaction flow containing the first reaction oil gas containing light olefins and the first catalyst to be regenerated after cooling to obtain the first reaction oil gas containing light olefins and the first catalyst to be regenerated, then performing a charring regeneration treatment on the first catalyst to be regenerated, and returning it to the first catalytic conversion reactor as a regenerated catalyst, and performing separation means such as distillation and fractionation on the first reaction oil gas containing light olefins to obtain the light olefins and hydrocarbon components of the present invention.

[0141] In addition, in one embodiment of the present invention, the separated hydrocarbon components are refluxed as hydrocarbon feedstock.

[0142] The present invention also allows the catalytic cracking process for hydrocarbon feedstocks to be coupled with the catalytic cracking process for heavy oil, thereby enabling the production of a variety of desired products. This leverages the respective advantages of different processes for producing light olefins from different feedstocks, improving both the yield and selectivity of light olefins while also increasing the utilization rate of petroleum resources. Furthermore, the catalyst removed from the slide valve can be used as at least a portion of the catalyst for the catalytic cracking of heavy oil, further reducing reaction energy consumption.

[0143] Therefore, the method of the present invention may further comprise the steps of:

[0144] The heavy hydrocarbon oil is contacted with a second catalyst in a second catalytic conversion reactor (hereinafter sometimes referred to as a second reactor) to perform a second catalytic conversion reaction to obtain a second reactant stream comprising a second reaction oil gas containing light oil and a second spent catalyst;

[0145] The second reactant stream is mixed with the first reactant stream, and the mixed stream is subjected to a first separation to obtain a mixed reactant stream containing light olefins (a mixture of the first reaction oil gas containing light olefins and the second reaction oil gas containing light oil) and a mixed spent catalyst (a mixture of the first spent catalyst and the second spent catalyst);

[0146] The mixed reaction flow containing light olefins is fractionated to separate dry gas, light olefins and C5 and above distillate oil, the C5 and above distillate oil is subjected to a second separation and the separated hydrocarbon components are returned to the first catalytic conversion reactor as a hydrocarbon feedstock; and the mixed catalyst to be regenerated by burning, and the regenerated catalyst is returned to the first catalytic conversion reactor as a first regenerated catalyst and to the second catalytic conversion reactor as a second regenerated catalyst.

[0147] In one embodiment of the present invention, the second catalyst comprises a reacted catalyst removed from the slide valve of the first catalytic conversion reactor. Preferably, part or all of the second catalyst is a reacted catalyst removed from the slide valve of the first catalytic conversion reactor.

[0148] In one embodiment of the present invention, the heavy hydrocarbon oil is one or more selected from vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, heavy aromatic raffinate oil, coal liquefaction oil, oil sands oil and shale oil.

[0149] In one embodiment of the present invention, the conditions of the second catalytic conversion reaction include: reaction temperature of 500-600°C, preferably 530-580°C; reaction pressure of 0.01-1MPa, preferably 0.05-1MPa; reaction time of 0.01-100s, preferably 0.1-80s.

[0150] In one embodiment of the present invention, the weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-70):1.

[0151] In one embodiment of the present invention, a second cooling zone is provided downstream of the reaction zone of the second catalytic conversion reactor. When the temperature of the second reaction flow containing the second reaction oil gas containing light oil and the second catalyst to be generated exceeds 530°C in the second catalytic conversion reactor, the second reaction flow is cooled to below 530°C.

[0152] In one embodiment of the present invention, the position of the second cooling zone provided in the second catalytic conversion reactor is not particularly limited, and those skilled in the art can select it as needed, as long as the second reactant flow with a temperature exceeding 530°C can be cooled to below 530°C.

[0153] In one embodiment of the present invention, the cooling means of the second cooling zone is not particularly limited and may be the cooling means used in the cooling zone of the first catalytic conversion reactor described above.

[0154] The present invention further provides a system for producing light olefins from hydrocarbon feedstocks, characterized in that the system comprises a first catalytic conversion reactor,

[0155] The first catalytic conversion reactor comprises, from bottom to top, a first lifting section, an expanding section, a dense phase fluidized bed section, a cooling zone, a reducing section, a second lifting section and a top outlet;

[0156] Wherein, the cooling zone is arranged downstream of the dense fluidized bed section, at a position where the catalyst density is reduced to 80% to 20% of the catalyst density of the dense fluidized bed section, preferably at a position where the catalyst density is reduced to 70% to 30% of the catalyst density of the dense fluidized bed section.

[0157] In one embodiment of the present invention, a slide valve for taking out the spent catalyst is provided after the cooling zone and before the second lifting section.

[0158] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the angle between the side wall of the expanded diameter section of the first catalytic conversion reactor and the axis is 5-60 degrees.

[0159] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the ratio of the diameter to the height of the dense phase fluidized bed section of the first catalytic conversion reactor is (1-20):1.

[0160] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the angle between the side wall of the reduced diameter section of the first catalytic conversion reactor and the axis is 5-60 degrees.

[0161] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the head of the first lifting section of the first catalytic conversion reactor is provided with a catalyst inlet and a lifting medium inlet; the middle of the first lifting section is provided with a feedstock inlet.

[0162] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, a slide valve is provided on the side of the expanded diameter section.

[0163] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, a gas-solid mixed fluid distributor is further provided at the tail of the first rising section of the first catalytic conversion reactor.

[0164] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the cooling zone is provided with a cooling medium distributor for introducing cooling medium, and the cooling medium distributor is arranged in a ring shape along the circumference of the catalytic conversion reactor.

[0165] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the cooling zone is provided with a heat collector arranged along the circumference of the catalytic conversion reactor.

[0166] In one embodiment of the present invention, the system for producing light olefins from hydrocarbon feedstock further comprises a regenerator, a settler, a fractionating tower and an alkane-olefin separation device.

[0167] The top outlet of the first catalytic conversion reactor is connected to the inlet of the settler, the catalyst outlet of the settler is connected to the regenerator, the oil and gas outlet of the settler is connected to the inlet of the fractionation tower, and the outlet of the fractionation tower is connected to the inlet of the alkane-olefin separation device.

[0168] In one embodiment of the present invention, the olefin-containing fraction outlet of the alkane-olefin separation unit is communicated with the feed inlet of the first catalytic conversion reactor.

[0169] In one embodiment of the present invention, the regenerated catalyst outlet of the regenerator is communicated with the catalyst inlet of the first catalytic conversion reactor.

[0170] In one embodiment of the present invention, the system for producing light olefins from hydrocarbon feedstock further comprises a second catalytic conversion reactor, which is a riser reactor.

[0171] The riser reactor of the second catalytic conversion reactor is provided with a heavy hydrocarbon oil feedstock inlet at the bottom, a catalyst inlet at the bottom, a pre-lifting medium inlet and a top outlet.

[0172] The top outlet of the second catalytic conversion reactor is connected to the inlet of the settler,

[0173] The regenerated catalyst outlet of the regenerator is communicated with the catalyst inlet of the first catalytic conversion reactor and the catalyst inlet of the second catalytic conversion reactor.

[0174] In one embodiment of the present invention, it is preferred that the slide valve of the first catalytic conversion reactor is connected to the catalyst inlet of the second catalytic conversion reactor through a pipeline.

[0175] It should be noted that, unless otherwise specified, the reaction pressure in the present invention refers to absolute pressure.

[0176] Hereinafter, the present invention will be described in further detail with reference to the accompanying drawings, but the present invention is not limited to the embodiments shown in the drawings.

[0177] The present invention will be described in detail below with reference to the accompanying drawings.

[0178] As shown in Figure 1, the first catalytic converter reactor is a fluidized bed reactor. From bottom to top, the first catalytic converter reactor comprises a first riser section, an expansion section, a dense fluidized bed section, a cooling zone, a reduction section, and a second riser section. The diameter of the first riser section is 0.2-5 m, and its height accounts for 5-20% of the total height of the first reactor. The angle between the sidewall of the expansion section and the axis is 5-60 degrees, and the height of the expansion section accounts for 1-10% of the height of the first reactor. The ratio of the diameter to height of the dense fluidized bed section is (1-20:1), and its height accounts for 20-70% of the total height of the first reactor. The junction between the dense fluidized bed section and the second riser section is a reduction section. The angle between the sidewall of the reduction section and the axis is 5-60 degrees, and its height accounts for 5-20% of the total height of the first reactor. The ratio of the diameter of the second riser section to the diameter of the reaction zone is (0.2-0.8:1), and the height of the second riser section accounts for 1-20% of the total height of the first catalytic converter reactor. The cooling zone is located between the dense fluidized bed section and the reduced diameter section, where the catalyst density drops to 80% to 20% of the catalyst density in the dense fluidized bed layer, preferably where the catalyst density drops to 70% to 30% of the catalyst density in the dense fluidized bed layer.

[0179] In the first reactor shown in Figure 1, a pre-lifting medium enters the first lifting section 33 from the bottom of the first reactor A via pipeline 1. The first catalyst from pipeline 24, lifted by the pre-lifting medium, ascends into the dense-phase fluidized bed reaction zone of the first reactor A. A hydrocarbon feedstock is injected into the bottom of the reaction zone via pipeline 2. After being distributed by material distributor 3, it comes into contact with the first catalyst, preheated to above 700°C, in the dense-phase fluidized bed, undergoing a catalytic cracking reaction. The reaction proceeds at a temperature of 550-800°C, producing a first reactant stream comprising a first reaction oil and gas containing light olefins and a first spent catalyst. In the cooling zone, the cooling medium is introduced into the cooling medium distributor 35 located therein via pipeline 4. The reactant stream directly contacts the cooling medium, rapidly cooling it. Within 0.5-2 seconds (preferably 0.5-1 second), the reaction oil and gas are cooled to 450-530°C (preferably 480-500°C). The cooled first reactant stream undergoes rapid gas-solid separation to produce the first reaction oil and gas and the first spent catalyst. The first reaction oil and gas then exit the first reactor A via the second riser. The catalyst in the dense phase fluidized bed section is removed from the first reactor A via pipeline 8 via slide valve 7, maintaining the catalyst density at the set value.

[0180] Figure 2 shows a first reactor according to another embodiment of the present invention. This first reactor differs from the first reactor shown in Figure 1 in that a heat extractor is provided in the cooling zone. In the reaction apparatus shown in Figure 2, a pre-lifting medium enters the first lifting section 33 from the bottom of the first reactor A via pipeline 1. The first catalyst, preheated to above 700°C, from pipeline 24 is accelerated upward along the first lifting section by the pre-lifting medium. A hydrocarbon feedstock is injected into the bottom of the reaction zone of the first reactor via pipeline 2 and, after distribution via material distributor 3, comes into contact with the first catalyst, preheated to above 700°C, in a dense fluidized bed to react. The reaction proceeds at a temperature of 550-800°C, producing a first reactant stream comprising a first reaction oil and gas containing light olefins and a first spent catalyst. In the cooling zone, several heat exchangers are positioned along its circumference. Cooling medium is introduced into heat exchangers 39 via pipelines. The reaction products move upward, contacting the heat exchangers and cooling them. The reactant stream is cooled to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably 0.5-1 second) to prevent excessively high reaction temperatures, which could lead to deep reactions and secondary reactions. Catalyst in the dense fluidized bed section is removed from the first reactor A via pipeline 8 via slide valve 7, maintaining the catalyst density at the set value.

[0181] Figure 3 shows a first reactor according to another embodiment of the present invention. This first reactor differs from the first reactor shown in Figure 1 in that the feed position is different. A pre-lifting medium enters the first lifting section 33 from the bottom of the first reactor A via pipeline 1. The first catalyst from pipeline 24 ascends to the dense fluidized bed reaction zone under the lifting action of the pre-lifting medium. A hydrocarbon feedstock enters the dense fluidized bed reaction zone from the side of the first reactor via pipeline 36. After being distributed by material distributor 3, it comes into contact with the first catalyst, preheated to above 700°C, in the dense fluidized bed to undergo a catalytic cracking reaction. The reaction proceeds at a temperature of 550-800°C, producing a first reactant stream comprising a first reaction oil and gas containing light olefins and a first spent catalyst. In the cooling zone, the cooling medium is introduced via pipeline 4 into the cooling medium distributor 35 located therein. The reacted products come into direct contact with the cooling medium, cooling the reactant stream to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably 0.5-1 second). Rapid gas-solid separation then occurs to produce the first reaction gas and the first spent catalyst. The first reaction gas exits the first reactor via the second riser. The catalyst in the dense phase fluidized bed is removed from the first reactor A via pipeline 8 via slide valve 7, maintaining the catalyst density at the set value.

[0182] In a specific embodiment of the present invention, the method provided by the present invention can be completed according to the process shown in Figure 4. The pre-lifting medium enters from the bottom 2 of the first reactor through pipeline 1, and the first catalyst from pipeline 24 is accelerated upward along the first lifting section of the first reactor under the lifting effect of the pre-lifting medium. The hydrocarbon feedstock is injected into the bottom of the reaction zone through pipeline 2, and after being distributed by the material distributor 3 (not shown), it contacts the preheated first catalyst in a dense phase fluidized bed to undergo catalytic cracking reaction. The reaction is carried out at 550-800°C to obtain a first reaction stream. In the cooling zone, the reaction product contacts the cooling medium and is rapidly cooled. Within 0.5-2 seconds (preferably within 0.5-1 second), the reaction stream is cooled to 450-530°C (preferably 480-500°C), and then gas-solid separation is performed to obtain the first reaction oil and gas and the first catalyst to be generated. The first reaction oil and gas leave the first reactor through the second lifting section. Among them, the catalyst in the dense phase fluidized bed section is controlled by the slide valve 7 through the pipeline 8 so that the catalyst density is maintained at a set value, and the taken out catalyst is introduced into the stripping section 9, and contacts with the stripping steam from the pipeline 25 to strip out the remaining reaction oil and gas on the catalyst. The reaction oil and gas obtained by stripping from the first catalyst to be regenerated is separated by the cyclone separator 13 and then enters the gas collecting chamber 14.

[0183] After stripping, the first spent catalyst enters regenerator 16 via regeneration inclined pipe 15. It then comes into contact with oxygen-containing gas introduced into the regenerator via pipeline 17, where it undergoes char regeneration. This removes coke from the spent catalyst and regenerates the deactivated first spent catalyst. Supplemental fuel enters the regenerator via pipeline 18 to replenish heat for the regenerated first catalyst.

[0184] The reaction oil and gas leaving the second rising section of the first reactor enters the fractionation tower 21 through the large oil and gas pipeline 20 for the first separation. The separated hydrogen, methane and ethane are drawn out through pipeline 22, ethylene is drawn out through pipeline 23, propylene is drawn out through pipeline 26, and butene is drawn out through pipeline 27. Butene may or may not be returned to the first reactor as a feedstock for further reaction. Propane and butane are drawn out through pipeline 28. The first catalytic cracking distillate oil with an initial boiling point of any temperature greater than 20°C and less than 140°C is introduced into the alkane-olefin separation unit 30 through pipeline 29 for the second separation treatment. The separation produces an olefin-free stream and an olefin-rich stream. The olefin-free stream is drawn out through pipeline 31, and the olefin-rich stream is returned to the first reactor through pipeline 32 as a feedstock for further reaction.

[0185] In the present invention, the catalyst separation device and the separation device for the first reaction oil gas containing light olefins in FIG. 4 of the present invention are applicable to other embodiments of the present invention, such as the embodiments in FIG. 1-3 .

[0186] In another specific embodiment of the present invention, as shown in Figure 5, the difference between it and the process shown in Figure 4 is that the destination of the catalyst to be regenerated after the reaction in the first reactor is different. In this specific embodiment, the catalyst in the dense phase fluidized bed section in the first reactor is controlled by a slide valve 7, enters the bottom of the first reactor A through pipeline 8, and is mixed with the regenerated first catalyst from pipeline 24 and then sent to the reaction zone of the first reactor to participate in the reaction again.

[0187] In another embodiment of the present invention, as shown in Figure 6, a first reactor A is coupled to a second reactor B. A pre-lifting medium enters a first lifting section 33 from the bottom of the first reactor A via pipeline 1. The first catalyst from pipeline 24 ascends to the reaction zone under the lifting action of the pre-lifting medium. A hydrocarbon feedstock is injected into the bottom of the reaction zone of the first reactor A via pipeline 2. After distribution through a material distributor 3 (not shown), the feedstock reacts in a dense fluidized bed. The post-reaction stream is rapidly cooled in a cooling zone and undergoes rapid gas-solid separation, yielding a first reaction oil and gas and a first spent catalyst.

[0188] Heavy feedstock oil is injected into the bottom of the second reactor B via pipeline 5 along with atomizing steam from pipeline 6. In the reaction zone of the second reactor B, the heavy feedstock oil contacts and reacts with the second catalyst introduced via pipeline 19, producing a second reaction stream containing second reaction oil and gas containing light oil and second spent catalyst. The second reaction stream is cooled in a cooling zone upstream of the reaction zone. The catalyst in the dense phase fluidized bed section of the first reactor A is controlled by a slide valve 7 and introduced into the stripping section 9 from the bottom of the reaction zone of the first reactor A via pipeline 8, where it contacts stripping steam from pipeline 25. The oil and gas stripped from the spent catalyst pass through a cyclone separator 13 and into a plenum 14. The stripped spent catalyst enters a regenerator 16 via a regeneration slant pipe 15. Main air enters the regenerator 16 via pipeline 17 to remove coke from the spent catalyst and regenerate the deactivated spent catalyst. Makeup fuel enters the regenerator via pipeline 18 to replenish heat for the regenerated catalyst. The preheated regenerated catalyst enters the second reactor B via pipeline 19 and enters the first reactor A via pipeline 24.

[0189] The first reaction oil and gas and the second reaction oil and gas containing light oil enter the distillation tower 21 through the large oil and gas pipeline 20 for the first separation treatment. The separated hydrogen, methane and ethane are drawn out through pipeline 22, ethylene is drawn out through pipeline 23, propylene is drawn out through pipeline 26, and butene is drawn out through pipeline 27. Butene may or may not be returned to the first reactor A for further reaction. Propane and butane are drawn out through pipeline 28. The first catalytic cracking distillate oil with an initial boiling point of any temperature greater than 20°C and less than 140°C is introduced into the alkane-olefin separation unit 30 through pipeline 29 for the second separation treatment. The olefin-free stream and the olefin-rich hydrocarbon component are separated: the olefin-free stream is drawn out through pipeline 31, and the olefin-rich hydrocarbon component is returned to the first reactor A through pipeline 32 as a feedstock for further reaction.

[0190] The seventh embodiment of the present invention is shown in Figures 1 and 7. The difference between it and the embodiment shown in Figure 6 is that the destination of the catalyst in the dense phase fluidized bed section in the first reactor A is different. The catalyst in the dense phase fluidized bed section is controlled by a slide valve 7 and enters the first rising section of the second reactor B from the bottom of the first reactor A through pipeline 37, where it is mixed with the regenerated catalyst from pipeline 19 and contacts and reacts with the heavy crude oil from pipeline 5.

[0191] In the present invention, the following specific embodiments are provided.

[0192] The present invention provides a catalytic conversion method for producing light olefins, characterized in that the method comprises the following steps:

[0193] The olefin-rich raw material is injected into the dense phase fluidized bed with a density of 100-700 kg / m 3The hot regenerated catalyst contacts and undergoes a catalytic conversion reaction at a reaction temperature of 550-800°C. Once the post-reaction logistics leaves the dense phase fluidized bed, it is cooled to 450-530°C within 2 seconds and then enters the subsequent gas-solid separation. The regenerated catalyst after gas-solid separation is stripped and then enters the regenerator, where the reaction oil and gas are separated into products such as ethylene and propylene.

[0194] Optionally, the post-reaction logistics is cooled to the target temperature within 2 seconds, preferably within 1 second, and more preferably within 0.5 seconds.

[0195] Optionally, the catalyst density in the dense phase fluidized bed is 100-700 kg / m 3 , preferably 300-650kg / m 3 , more preferably 500-650kg / m 3 .

[0196] Optionally, the catalyst storage in the dense phase fluidized bed is regulated by a slide valve, and excess catalyst is transported to other parts of the device.

[0197] Optionally, the conditions for the catalytic conversion reaction include: a reaction temperature of 550-800°C, preferably 580-750°C, and more preferably 600-700°C;

[0198] The reaction pressure is 0.01-1 MPa, preferably 0.1-0.8 MPa, and more preferably 0.2-0.5 MPa;

[0199] The reaction time is 0.05-10 seconds, preferably 0.1-5 seconds, and more preferably 0.2-2 seconds;

[0200] The weight ratio of the catalyst to the olefin-rich feedstock is (5-50):1, preferably (10-35):1, and more preferably (12-30):1.

[0201] Optionally, the olefin content in the olefin-rich feedstock is 50-100 wt%, preferably 80-100 wt%;

[0202] The olefin-rich raw material is a gaseous feed;

[0203] The olefins in the olefin-rich feedstock are C4-C 12 Olefins, preferably C4-C6 olefins.

[0204] Optionally, the reactor comprises, from bottom to top, a first lifting section, an expansion section, a dense phase fluidization section, a reduction section, and a second lifting section; the angle between the side wall of the expansion section and the axis is 5-60 degrees; the ratio of the diameter to the height of the dense phase fluidization section is (1-20):1; the angle between the side wall of the reduction section and the axis is 5-60 degrees;

[0205] The head of the dense phase fluidization section is also provided with a material distributor;

[0206] The cooling zone is arranged at the tail end of the dense phase fluidization section;

[0207] The cooling zone is provided with a cooling distributor or a heat extractor;

[0208] The cooling medium introduced by the cooling distributor is mixed with the reaction product and cooled to the target temperature within a preset time;

[0209] The heat collector is arranged along the circumference of the tail of the reactor, and the heat collector is filled with cooling medium.

[0210] The cooling medium is selected from one or more of liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel and water. The above-mentioned coolant can also be used as a second raw material to undergo cracking reaction in the cooling zone, absorb heat, and quickly cool the reaction materials in the reaction zone.

[0211] Optionally, the catalyst is a medium-pore molecular sieve catalyst and / or a small-pore molecular sieve catalyst;

[0212] The mesoporous molecular sieve catalyst is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48;

[0213] The small pore molecular sieve catalyst is selected from one or more of SAPO-34, SAPO-11 and SAPO-47.

[0214] Optionally, the method further includes:

[0215] The spent catalyst is stripped, and then the stripped spent catalyst is charred and regenerated, and the regenerated catalyst is returned to the reactor; or the spent catalyst and the regenerated catalyst are mixed and then returned to the reactor.

[0216] Optionally, the method further includes:

[0217] The reactor, catalyst, and reaction oil gas are named as the first reactor, the first catalyst, and the first reaction oil gas. The heavy hydrocarbon oil is brought into contact with the second catalyst in the second reactor to perform a second catalytic conversion reaction, thereby obtaining reaction oil gas containing light oil and a second spent catalyst.

[0218] Then, the reaction oil gas containing light oil is mixed with the first reaction oil gas, and the mixed oil gas is subjected to a first separation to obtain dry gas, light olefins and C5 and above distillate oil, and the C5 and above distillate oil is subjected to a second separation and the separated olefin-rich component is returned to the first reactor;

[0219] The second spent catalyst is stripped and the stripped second spent catalyst is charred and regenerated, and then the regenerated second catalyst is returned to the second reactor; and the first spent catalyst is stripped and then transported to the regenerator for charred and regeneration.

[0220] Optionally, the method further includes:

[0221] mixing the first catalyst taken out through the slide valve with the hot regenerated second catalyst to obtain a mixed catalyst;

[0222] The heavy hydrocarbon oil is contacted with the mixed catalyst in a second reactor to perform a second catalytic conversion reaction to obtain a reaction oil gas containing light oil and a spent catalyst; wherein, when the temperature of the reaction oil gas containing light oil and the spent catalyst in the upper region of the reaction zone of the second reactor exceeds 530° C., a cooling zone is provided downstream of the reaction zone to cool the reaction oil gas containing light oil and the spent catalyst to below 530° C.;

[0223] stripping the spent catalyst, and charring and regenerating the stripped spent catalyst and returning it to the first reactor and the second reactor respectively;

[0224] The light oil-containing reaction oil gas is mixed with the first reaction oil gas, and the mixed oil gas is subjected to a first separation to obtain dry gas, light olefins and C5 and above distillate oils. The C5 and above distillate oils are subjected to a second separation and the separated olefin-rich components are returned to the first reactor.

[0225] Optionally, the heavy hydrocarbon oil is selected from one or more of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, heavy aromatic raffinate oil, coal liquefaction oil, oil sand oil and shale oil;

[0226] The conditions of the second catalytic conversion reaction include: reaction temperature of 500-600°C, preferably 530-580°C; reaction pressure of 0.01-1 MPa, preferably 0.05-1 MPa; reaction time of 0.01-100 s, preferably 0.1-80 s;

[0227] The weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-70):1.

[0228] Example

[0229] The present invention is further described in detail below by way of examples, but the present invention is not limited thereby. The raw materials used in the examples were all commercially available. The catalyst used in the examples and comparative examples was TCC-1, produced by the Qilu Branch of Sinopec Catalyst Co., Ltd.

[0230] The heavy hydrocarbon oil used in the examples and comparative examples of the present invention is heavy oil I, and the properties of heavy oil I are shown in Table 1.

[0231] Table 1

[0232] Example 1

[0233] The experiment of this embodiment was carried out on the process shown in Figure 1. The first reactor was a medium-sized dense phase fluidized bed reactor, the raw material was 1-pentene, and the catalyst was TCC-1.

[0234] The preheated raw material 1-pentene enters the bottom of the reaction zone of the first reactor and enters the reaction zone through the gas-solid mixed fluid distributor, where it contacts the first catalyst preheated to 700°C in the form of a dense phase fluidized bed for catalytic cracking reaction. The catalyst density is controlled at 400 kg / m 3 Downstream of the reactant flow, the density of the catalyst is reduced to 100 kg / m 3 A cooling zone is set up at the position of the reactor, using water as the cooling medium to rapidly cool the post-reaction stream. Within 1 second, the post-reaction stream is rapidly cooled to below 530°C in the cooling zone. A cyclone separator separates the stream into spent catalyst and ethylene- and propylene-rich oil and gas. The ethylene- and propylene-rich oil and gas are then sent to a subsequent separation unit for further separation. During the reaction, the catalyst in the dense fluidized bed section is removed from the bottom of the reactor's reaction zone using a slide valve. The reaction conditions and product distribution are shown in Table 2.

[0235] Example 2

[0236] The experiments in this example were conducted on a medium-sized fluidized bed reactor in the flow diagram shown in Figure 1. The raw material was 1-pentene and the catalyst was TCC-1. The difference from Example 1 is that the catalyst density was reduced to 300 kg / m downstream of the reactant flow. 3 The cooling zone was set at the position of , and the reaction conditions and product distribution are shown in Table 2.

[0237] Comparative Example 1

[0238] The experiment of this comparative example was conducted on a medium-sized fluidized bed reactor of the process shown in Figure 4. The raw material was 1-pentene and the catalyst was TCC-1. The difference between this comparative example and Example 1 was that the density of the first catalyst in the dense phase fluidized bed of the first reactor was 90 kg / m3 , and no cooling was performed after the catalytic conversion reaction. The reaction conditions and product distribution are shown in Table 2.

[0239] Table 2

[0240] As can be seen from Table 2, the method of the present invention has a higher yield of ethylene and propylene when high-temperature cracking is carried out in a fluidized bed reactor. The content of ethylene, propylene and butene in the obtained reaction oil and gas is as high as 63.62%, and the ethylene / propylene ratio is as high as 0.76.

[0241] Example 3

[0242] The test of this embodiment was carried out on the process shown in FIG7 , and the first reactor was a medium-sized dense-phase fluidized bed reactor.

[0243] The hot raw material 1-pentene enters the bottom of the reaction zone of the first reactor and contacts with the TCC-1 catalyst preheated to 700℃ in the form of a dense phase fluidized bed to carry out the first catalytic conversion reaction. The catalyst density is controlled at 400kg / m 3 ; Downstream of the reactant flow, the density of the catalyst is reduced to 100 kg / m 3 A cooling zone is set up at the position of the reactor, and water is used as the cooling medium to rapidly cool the post-reaction stream, reducing the temperature to 500°C within 1 second. The cooled reactant stream is separated in a cyclone separator to obtain the first reaction oil and gas containing light olefins and the first spent catalyst. During the reaction, the catalyst in the dense phase fluidized bed section is fed from the bottom of the reaction zone of the first reactor to the bottom of the second reactor via a slide valve.

[0244] The heavy oil I is introduced into the second reactor from the bottom of the second reactor and contacts with the mixed catalyst of the regenerated TCC-1 catalyst and the catalyst from the first reactor to undergo a second catalytic conversion reaction, thereby obtaining a second reaction oil gas containing light oil and a second catalyst to be regenerated.

[0245] The first catalyst to be regenerated and the second catalyst to be regenerated enter the regenerator for charring and regeneration to obtain a regenerated catalyst.

[0246] The first reaction gas containing light olefins and the second reaction gas containing light oil were mixed and fed into a fractionation unit, where they were fractionated according to the distillation range to produce ethylene, propylene, butene, and an olefin-containing stream. The olefin-containing stream was then introduced into an alkane-olefin separation unit for separation to produce an olefin-rich hydrocarbon fraction (the olefin-rich hydrocarbon fraction had an olefin content of 80% by weight). This olefin-rich hydrocarbon fraction was then fed to the bottom of the reaction zone of the first reactor and returned to the reactor. The reaction conditions and product distribution are shown in Table 3.

[0247] Comparative Example 2

[0248] The experiment of this comparative example was carried out with reference to Example 2, except that no cooling was performed after the catalytic conversion reaction. The reaction conditions and product distribution are shown in Table 3.

[0249] Example 4

[0250] The test of this example was carried out on a pilot plant of the first reactor in the flow chart shown in FIG6 .

[0251] Hot raw material 1-pentene enters the bottom of the reaction zone of the first reactor and mixes with the preheated 1-pentene to 700℃ and the density controlled at 400kg / m 3 The catalyst contacts and catalytic conversion reaction occurs; in the downstream of the reactant flow, the density of the catalyst is reduced to 100 kg / m 3 A cooling zone is set up at the position of the reactor. The post-reaction stream is cooled in a heat extractor to 500°C within 1 second. The cooled stream is separated in a cyclone separator to produce a first reaction gas containing light olefins and a first spent catalyst. During the reaction, the catalyst in the dense phase fluidized bed is controlled by a slide valve at the bottom of the reaction zone of the first reactor and introduced into the stripping section of the second reactor after gas-solid separation to produce spent catalyst. The heavy feedstock and the second catalyst are contacted and reacted at the bottom of the second reactor at a temperature of 560°C, a pressure of 0.2 MPa, and a reaction time of 6 seconds. The weight ratio of the second catalyst to heavy oil (I) is 5:1. This produces the second reaction gas and spent catalyst. The spent catalyst enters a regenerator for regeneration. The reaction products are fractionated according to the distillation range in a product fractionator to produce ethylene, propylene, butenes, and a crude olefin-containing stream. The crude olefin-containing stream continued to flow into an alkane-olefin separation unit to produce an olefin-rich hydrocarbon fraction. The olefin-rich hydrocarbon fraction had an olefin content of 80% by weight. This olefin-rich hydrocarbon fraction was introduced into the first reactor from the bottom of the reaction zone of the first reactor. The reaction conditions and product distribution are shown in Table 4.

[0252] Comparative Example 3

[0253] The experiment of this comparative example was conducted with reference to Example 3. The difference from Example 3 is that the catalyst in the dense phase fluidized bed was not removed during the reaction. The reaction conditions and product distribution are shown in Table 4.

[0254] Table 3

[0255] Table 4

[0256] As can be seen from Tables 2 to 4, by coupling the production of light olefins from light feedstocks with the catalytic cracking of heavy oil, adjusting the density of the catalyst in the catalytic cracking reactor for light feedstocks, and providing cooling zones at appropriate locations for cooling, the yields of ethylene, propylene, and butene in the resulting reaction oil and gas were significantly improved. Furthermore, removing part of the spent catalyst through a slide valve can reduce the energy consumption of the cooling zone, thereby reducing the overall energy consumption of the reaction.

[0257] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0258] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0259] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A catalytic conversion method for producing light olefins, the method comprising the following steps: In a dense phase fluidized bed layer of a first catalytic conversion reactor, the hydrocarbon feedstock is contacted with the first catalyst and a catalytic conversion reaction occurs. The reaction temperature is 550-800° C. to obtain a first reaction gas containing light olefins and a first catalyst to be produced. The first reaction gas is then cooled to 450-530° C. in a cooling zone. The catalyst density is set to a value selected from 100-700 kg / m 3 between; The catalyst is taken out from the dense phase fluidized bed through the slide valve to keep the catalyst density in the dense phase fluidized bed at the set value. The first reaction oil and gas containing light olefins is separated to obtain light olefins, Among them, a cooling zone is set at a position where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense fluidized bed layer, and preferably a cooling zone is set at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense fluidized bed layer, to cool the first reaction flow.

2. The catalytic conversion method according to claim 1, wherein: The catalyst taken out through the slide valve is regenerated after optional stripping.

3. The catalytic conversion method according to claim 1, wherein: The catalyst taken out through the slide valve returns to the catalyst inlet of the first catalytic conversion reactor, mixes with the first catalyst, and then enters the reaction zone of the first catalytic conversion reactor again.

4. The catalytic conversion method according to claim 1, wherein: The catalyst taken out through the slide valve is used for the second catalytic conversion reaction.

5. The method according to any one of claims 1 to 4, wherein: In the cooling zone, Use a cooling medium distributor to cool down; or use a heat extractor to cool down. The cooling medium in the cooling medium distributor or the heat extractor is at least one selected from liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel and water.

6. The method according to any one of claims 1 to 5, wherein: In the cooling zone, the reacted stream is cooled to 450-530°C, preferably 480-500°C, within 0.5-2 seconds, preferably within 0.5-1 second.

7. The method according to any one of claims 1 to 6, wherein: In the dense phase fluidized bed of the first catalytic conversion reactor, the catalyst density is set to a value selected from 300-650 kg / m 3 , preferably selected from 500-650kg / m 3 .

8. The method according to any one of claims 1 to 7, wherein: The conditions of the catalytic conversion reaction include: reaction temperature of 580-750°C, preferably 600-700°C; reaction time of 0.05-10 seconds, preferably 0.1-5 seconds, more preferably 0.2-2 seconds; reaction pressure of 0.01-1MPa, preferably 0.1-0.8MPa, more preferably 0.2-0.5MPa; The weight ratio of the catalyst to the hydrocarbon feedstock is (1-200):1, preferably (10-100):1, and further preferably (20-100):

1.

9. The method according to any one of claims 1 to 8, wherein: The first catalytic conversion reactor includes, from bottom to top, a first lifting section, an expanding section, a dense phase fluidized bed section, a cooling zone, a reducing section, and a second lifting section; The angle between the side wall of the expanded diameter section and the axis is 5-60 degrees; The ratio of the diameter to the height of the dense phase fluidization section is (1-20): 1; The angle between the side wall of the reduced diameter section and the axis is 5-60 degrees; The head of the first lifting section is provided with a first catalyst inlet and a lifting medium inlet; A raw material inlet is provided in the middle of the first lifting section; A gas-solid mixed fluid distributor is also provided at the tail of the first lifting section; The cooling zone is arranged downstream of the dense phase fluidization section, and is arranged at any position in the region where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense phase fluidized bed layer, and is preferably arranged at any position in the region where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense phase fluidized bed layer. The slide valve is arranged in the diameter expansion section.

10. The method according to any one of claims 1 to 9, wherein: Based on the total weight of the first catalyst, the first catalyst comprises 1-50 wt % of molecular sieve, 5-99 wt % of inorganic oxide and 0-70 wt % of clay; and / or The molecular sieve is at least one selected from ZSM-5 series molecular sieves and SAPO series molecular sieves; preferably at least one selected from ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48, SAPO-34, SAPO-11 and SAPO-47; and / or The silicon to aluminum ratio of the molecular sieve is 10-1000; and / or The inorganic oxide is selected from one or more of silicon dioxide and aluminum oxide; and / or The clay is selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

11. The method according to any one of claims 1 to 10, wherein: The hydrocarbon feedstock is a gas phase feed; and / or The content of C5-C8 olefins in the hydrocarbon feedstock is 50-100wt%, preferably 80-100wt%, more preferably 90-100wt%; and / or The hydrocarbon feedstock is selected from at least one of the C5 and above fractions produced by an alkane dehydrogenation unit, the C5 and above fractions produced by a catalytic cracking unit in a refinery, the C5 and above fractions produced by a steam cracking unit in an ethylene plant, the C5 and above olefin-rich fractions produced as a by-product of MTO, and the C5 and above olefin-rich fractions produced as a by-product of MTP.

12. The method according to any one of claims 1 to 11, wherein: The method further comprises the steps of: performing gas-solid separation on the first reaction flow containing the first reaction oil gas containing light olefins and the first catalyst to be regenerated after the temperature is reduced to obtain the first reaction oil gas containing light olefins and the first catalyst to be regenerated, and then performing a charring regeneration treatment on the first catalyst to be regenerated and returning it to the first catalytic conversion reactor as a first regenerated catalyst; Fractionating the first reaction oil gas containing light olefins to obtain light olefins and hydrocarbon components; The hydrocarbon component is refluxed as a hydrocarbon feedstock.

13. The method according to any one of claims 1 to 12, wherein: The method further comprises the following steps: The heavy hydrocarbon oil is brought into contact with a second catalyst in a second catalytic conversion reactor to perform a second catalytic conversion reaction, thereby obtaining a second reaction flow containing a second reaction oil gas containing light oil and a second catalyst to be spent; The second reaction stream is mixed with the first reaction stream, and the mixed mixed stream is subjected to a first separation to obtain a mixed reaction stream containing light olefins and a mixed spent catalyst; The mixed reaction flow containing light olefins is fractionated to separate dry gas, light olefins and C5 and above distillates, the C5 and above distillates are subjected to a second separation and the separated hydrocarbon components are returned to the first catalytic conversion reactor as a hydrocarbon feedstock; and the mixed spent catalyst is charred and regenerated, and the regenerated catalyst is returned to the first catalytic conversion reactor as a first regenerated catalyst and returned to the second catalytic conversion reactor as a second regenerated catalyst, Preferably, the second catalyst comprises a reacted catalyst taken out from the slide valve of the first catalytic conversion reactor, and more preferably, part or all of the second catalyst is a reacted catalyst taken out from the slide valve of the first catalytic conversion reactor.

14. The method according to claim 13, wherein: The heavy hydrocarbon oil is selected from one or more of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, heavy aromatic raffinate oil, coal liquefaction oil, oil sand oil and shale oil; and / or The conditions of the second catalytic conversion reaction include: reaction temperature of 500-600°C, preferably 530-580°C; reaction pressure of 0.01-1MPa, preferably 0.05-1MPa; reaction time of 0.01-100s, preferably 0.1-80s; and / or The weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-70):

1.

15. The method according to claim 11, wherein: A second cooling zone is arranged downstream of the reaction zone of the second catalytic conversion reactor. When the temperature of the second reaction flow containing the second reaction oil gas containing light oil and the second catalyst to be generated exceeds 530°C in the second catalytic conversion reactor, the second reaction flow is cooled to below 530°C.

16. A system for producing light olefins from hydrocarbon feedstocks, characterized in that: The system includes a first catalytic conversion reactor, The first catalytic conversion reactor includes, from bottom to top, a first lifting section, an expansion section, a dense phase fluidized bed section, a cooling zone, a reduction section, a second lifting section and a top outlet; The angle between the side wall of the expanded diameter section and the axis is 5-60 degrees; The ratio of the diameter to the height of the dense phase fluidized bed section is (1-20): 1; The angle between the side wall of the reduced diameter section and the axis is 5-60 degrees; The head of the first lifting section is provided with a catalyst inlet and a lifting medium inlet; A raw material inlet is provided in the middle of the first lifting section; A gas-solid mixed fluid distributor is also provided at the tail of the first lifting section; The cooling zone is arranged downstream of the dense phase fluidized bed section, and is arranged at a position where the catalyst density is reduced to 80% to 20% of the catalyst density in the dense phase fluidized bed section, and is preferably arranged at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense phase fluidized bed section. The slide valve is arranged in the expanded diameter section.

17. The system of claim 16, wherein: The cooling zone is provided with a cooling medium distributor for introducing cooling medium, and the cooling medium distributor is arranged in an annular shape along the circumference of the catalytic conversion reactor, or The cooling zone is provided with a heat collector arranged along the circumference of the catalytic conversion reactor.

18. The system according to any one of claims 16-17, further comprising a regenerator, a settler, a fractionation tower and an alkane-olefin separation device, The top outlet of the first catalytic conversion reactor is connected to the inlet of the settler, The catalyst outlet of the settler is communicated with the regenerator, the oil and gas outlet of the settler is communicated with the inlet of the fractionation tower, and the outlet of the fractionation tower is communicated with the inlet of the alkane-olefin separation device. The olefin fraction outlet of the alkane-olefin separation device is connected to the feed inlet of the first catalytic conversion reactor, The regenerated catalyst outlet of the regenerator is communicated with the catalyst inlet of the first catalytic conversion reactor.

19. The system of any one of claims 16-18, further comprising a second catalytic converter reactor, wherein the second catalytic converter reactor is a riser reactor, The riser reactor of the second catalytic conversion reactor is provided with a heavy hydrocarbon oil feedstock inlet at the bottom, a catalyst inlet at the bottom, a pre-lifting medium inlet and a top outlet. The top outlet of the second catalytic conversion reactor is connected to the inlet of the settler, The regenerated catalyst outlet of the regenerator is communicated with the catalyst inlet of the first catalytic conversion reactor and the catalyst inlet of the second catalytic conversion reactor, Preferably, the slide valve of the first catalytic conversion reactor is connected to the catalyst inlet of the second catalytic conversion reactor through a pipeline.

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