Method and system for producing low-carbon olefin from hydrocarbon raw materials

Abstract

The present invention relates to a method for producing a low-carbon olefin from hydrocarbon raw materials. The method comprises the following steps: in a bed layer of a dense-phase fluidized bed in which the catalyst density of a first catalytic conversion reactor is 100-700 kg / m3, bringing hydrocarbon raw materials into contact with a first catalyst to perform a catalytic conversion reaction at a reaction temperature of 550-800ºC, so as to obtain a first reactant flow comprising a low-carbon-olefin-containing reaction oil gas and a first catalyst to be generated, then cooling the first reactant flow to 450-530ºC in a cooling region, and separating a low-carbon olefin from the first reactant flow. In the present invention, by cooling the reactant flow in the cooling region, control over a catalytic cracking reaction and a thermal cracking reaction is optimized; and by means of the immediate replenishment of the heat in the reaction region, the deep reaction occurring during the reaction process under low-temperature conditions is effectively inhibited, thereby improving the yield and selectivity of the low-carbon olefin.

Description

Method and system for producing light olefins from hydrocarbon feedstock Technical Field

[0001] The present invention belongs to the field of petrochemical industry, and in particular, relates to a method for producing light olefins from hydrocarbon raw materials and a system for implementing the method. Background Art

[0002] As an important organic chemical raw material, the consumption of light olefins has maintained a strong growth trend. Technologies for producing light olefins from petroleum include steam cracking, refinery fluid catalytic cracking, catalytic cracking, alkane dehydrogenation, and olefin disproportionation. The typical process for producing light olefins is steam cracking, which produces ethylene and propylene. This consumes large amounts of light hydrocarbons or chemical light hydrocarbons such as naphtha. However, due to the relatively heavy quality of domestic crude oil, the production capacity of chemical light oil is insufficient to meet the demand for light olefin feedstock. Moreover, as demand increases, traditional steam cracking processes have struggled to meet the market demand for light olefins.

[0003] CN114763483A discloses a catalytic conversion method for producing ethylene and propylene. By replacing the alkane feedstock with an olefin-rich feedstock, the yield of ethylene and propylene is effectively increased, while the selectivity for methane in the product is reduced. CN115108876A discloses a catalytic conversion method for producing light olefins using organic oxygenates as part of the feedstock. By performing catalytic conversion reactions on the olefin-rich feedstock, heavy feedstock, and organic oxygenate feedstock in different reaction zones of a catalytic conversion reactor, the advantages of different process routes are fully utilized to increase the yield and selectivity of light olefins, particularly ethylene and propylene.

[0004] To meet the needs of the petrochemical industry while also improving quality and efficiency, a process has been developed to produce light olefins by cracking higher olefins (with carbon atoms greater than or equal to 5) from refinery processes. However, the yield and selectivity of light olefins in existing processes still need to be further improved.

[0005] Summary of the Invention

[0006] The object of the present invention is to provide a method for producing light olefins from hydrocarbon feedstocks, which can significantly improve the yield and selectivity of light olefins obtained by cracking hydrocarbon feedstocks (especially high-carbon olefins with a carbon number of 5 or more) through a cracking process.

[0007] In order to achieve the above object, the present invention provides a method for producing light olefins from hydrocarbon feedstock, the method comprising the following steps:

[0008] The catalyst density in the first catalytic conversion reactor is 100-700 kg / m 3In a dense phase fluidized bed, a hydrocarbon feedstock is brought into contact with a first catalyst and a catalytic conversion reaction occurs at a reaction temperature of 550-800° C. to obtain a first reaction stream comprising reaction oil and gas containing light olefins and a first spent catalyst. The first reaction stream is then cooled to 450-530° C. in a cooling zone.

[0009] Then, light olefins are separated from the first reactant stream,

[0010] 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.

[0011] In the present invention, the method of the present invention may further include the following steps: performing gas-solid separation on the cooled first reaction stream to obtain reaction oil gas containing light olefins and a first spent catalyst, performing a char regeneration treatment on the first spent catalyst and returning it to the first catalytic conversion reactor as a first regenerated catalyst;

[0012] fractionating the reaction oil gas containing light olefins to obtain light olefins and an olefin-rich stream;

[0013] The olefin-rich stream is refluxed as a hydrocarbon feedstock.

[0014] In the present invention, the method of the present invention may further comprise the following steps:

[0015] 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 reactant stream comprising a reaction oil gas containing light oil and a second spent catalyst;

[0016] Mixing the second reaction stream containing the reaction oil gas containing light oil and the second spent catalyst with the first reaction stream, and performing a first separation on the mixed stream to obtain a mixed reaction stream containing light olefins and a mixed spent catalyst;

[0017] 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 olefin-rich stream is returned to the first catalytic conversion reactor; 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.

[0018] In addition, the present invention provides a system for producing light olefins from hydrocarbon feedstocks, characterized in that the system comprises a first catalytic conversion reactor,

[0019] The first catalytic conversion reactor comprises, from bottom to top, a first riser section, an expansion section, a dense phase fluidized bed section, a cooling zone, a reduction section, a second riser section and a top outlet;

[0020] The angle between the side wall of the expanded diameter section and the axis is 5-60 degrees;

[0021] The ratio of the diameter to the height of the dense phase fluidized bed section is (0.1-20):1, preferably (0.1-10):1;

[0022] The angle between the side wall of the reduced diameter section and the axis is 5-60 degrees;

[0023] The head of the first lifting section is provided with a catalyst inlet and a lifting medium inlet;

[0024] A raw material inlet is provided in the middle of the first lifting section; or a raw material inlet is provided on the side wall of the diameter-expanding section;

[0025] A gas-solid mixed fluid distributor is also provided at the tail of the first lifting section;

[0026] 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 in the dense fluidized bed layer, and preferably at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense fluidized bed layer.

[0027] The system for producing light olefins from hydrocarbon feedstocks of the present invention may further comprise a regenerator, a settler, a fractionating tower and an alkane-olefin separation device.

[0028] 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 reaction 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.

[0029] The olefin fraction outlet of the alkane-olefin separation device is connected to the raw material inlet of the first catalytic conversion reactor,

[0030] The regenerated catalyst outlet of the regenerator is communicated with the catalyst inlet of the first catalytic conversion reactor.

[0031] Through the above technical solution, the present invention has the following beneficial effects:

[0032] (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;

[0033] (2) The present invention allows the olefin-rich raw materials to undergo catalytic conversion reactions within a suitable reaction temperature range by instantly adding heat to the dense phase fluidized bed, thereby reducing the adverse effects of excessive temperature drop during the reaction, promoting the unimolecular cracking reaction of light raw materials, and improving the yield and selectivity of high-value-added low-carbon olefins such as ethylene in the resulting products;

[0034] (3) In the method of the present invention, the stream after the catalytic reaction is cooled by entering a cooling step at a specific location, which can effectively inhibit the thermal cracking reaction during the reaction process and reduce the formation of by-products such as methane, thereby improving the yield and selectivity of light olefins;

[0035] (4) In the method of the present invention, the catalytic cracking process of the olefin-rich feedstock of the present invention can be coupled with the catalytic cracking process of heavy oil, thereby being used to produce a variety of target products, and being able to give full play to the respective advantages of the processes for producing light olefins from different feedstocks, thereby increasing the yield and selectivity of light olefins and improving the utilization rate of petroleum resources;

[0036] (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, thereby suppressing unnecessary thermal cracking reactions in the reaction flow and reducing the generation of by-products such as methane, thereby improving the yield and selectivity of light olefins.

[0037] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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:

[0039] FIG1 is a schematic diagram of an embodiment of a catalytic conversion reactor provided by the present invention.

[0040] FIG2 is a schematic diagram of another embodiment of the catalytic conversion reactor provided by the present invention.

[0041] FIG3 is a schematic diagram of another embodiment of the catalytic conversion reactor provided by the present invention.

[0042] FIG4 is a schematic diagram of another embodiment of the catalytic conversion reactor provided by the present invention.

[0043] FIG5 is a schematic diagram of an embodiment of the method for producing light olefins from hydrocarbon feedstocks provided by the present invention.

[0044] FIG6 is a schematic diagram of another embodiment of the method for producing light olefins from hydrocarbon feedstocks provided by the present invention.

[0045] BRIEF DESCRIPTION OF THE DRAWINGS

[0046] 1 pipeline 2 first lifting section 3 regeneration inclined pipe

[0047] 4 Feed pipeline 5 Gas-solid mixed fluid distributor 6 Pipeline

[0048] 7 pipeline 8 feed fluid distributor 9 heater

[0049] 10 Feed pipeline 11 First catalytic conversion reaction zone 12 Pipeline

[0050] 13 fluid distributor 14 cooling zone 15 heat exchanger

[0051] 16 pipeline 17 second lifting section 18 horizontal pipe

[0052] 19 pipeline 20 pre-lift medium 21 feed pipeline

[0053] 22 Pre-lift section 23 Second catalytic conversion reaction zone 24 Stripping steam

[0054] 25 stripping section 26 waiting for production inclined pipe 27 outlet section

[0055] 28 settler 29 gas collecting chamber 30 pipeline

[0056] 31 regenerator 32 regeneration inclined tube 33 fractionating tower

[0057] Pipeline 34, Pipeline 35, Pipeline 36

[0058] Pipeline 37, Pipeline 38, Pipeline 39

[0059] 40 Alkylene Separation Unit 41 Pipeline 42 Pipeline

[0060] Pipeline 43 and Pipeline 44 DETAILED DESCRIPTION

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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).

[0066] 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.

[0067] Therefore, the present invention provides a method for producing light olefins from hydrocarbon feedstock, the method comprising the following steps:

[0068] The catalyst density in the first catalytic conversion reactor is 100-700 kg / m 3In a dense phase fluidized bed, a hydrocarbon feedstock is brought into contact with a first catalyst (sometimes referred to as catalyst in the present invention) and a catalytic conversion reaction occurs at a reaction temperature of 550-800° C. to obtain a first reaction stream comprising 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.

[0069] Then, light olefins are separated from the first reactant stream,

[0070] 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) .

[0071] In the present invention, by cooling the reactant flow 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] In the present invention, the light olefin is at least one of ethylene, propylene, and butene. The reaction oil gas containing light olefins in the present invention comprises a mixture of ethylene, propylene, and butene.

[0080] In one embodiment of the present invention, heat is added to the dense fluidized bed in the bed region (this step is also referred to as a heat-addition step in the present invention) to maintain the reaction temperature at 550-800°C.

[0081] By adding heat to the dense phase fluidized bed, the hydrocarbon feedstock and the catalyst are kept at a suitable temperature for catalytic conversion reaction, thereby significantly inhibiting the polymerization reaction of olefin molecules caused by the cooling of the reaction materials during the reaction, reducing the formation of large molecular olefin products, and at the same time improving the selectivity and yield of low-carbon olefins in the product, especially ethylene products, thereby obtaining high-quality and highly selective target products.

[0082] In the heating supplement step of the present invention, there is no limitation on the heating supplement means, and various heating supplement means known in the art can be used, such as using a heat exchanger for heating, using an electric heater for heating, etc.

[0083] In one embodiment of the present invention, in the heating supplement step, heating is performed by an instant heat supplement system.

[0084] In one embodiment of the present invention, the instant heat replenishment system comprises a catalyst replenishment pipe for introducing additional hot catalyst and / or hot regenerated catalyst into the dense phase fluidized bed.

[0085] In one embodiment of the present invention, the instant heat supplement system includes a heat supplier disposed in the dense phase fluidized bed layer of the reactor.

[0086] In one embodiment of the present invention, the heating medium in the heater is at least one of high-temperature steam and steam cracking gas.

[0087] 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.

[0088] 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.

[0089] In one embodiment of the present invention, in the cooling step, the temperature is lowered by introducing a cooling medium.

[0090] In one embodiment of the present invention, in the cooling step, a fluid distributor for introducing the cooling medium is used to reduce the temperature.

[0091] In one embodiment of the present invention, in the cooling step, a heat extractor is used for cooling.

[0092] In one embodiment of the present invention, in the cooling zone, the fluid distributor is arranged in a ring shape along the circumference of the catalytic conversion reactor, and the cooling step is implemented by the cooling medium introduced through the fluid distributor.

[0093] 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.

[0094] In one embodiment of the present invention, the cooling medium is a coolant and / or a cooled catalyst; the coolant is at least one selected from liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel, water and olefins with eight or more carbon atoms.

[0095] In one embodiment of the present invention, the coolant in the heat exchanger is at least one selected from liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel, water and olefins having eight or more carbon atoms.

[0096] As a cooling method using a coolant, physical cooling can be used, or the above-mentioned coolant can be used as a second raw material to undergo a cracking reaction in the cooling zone to absorb heat, so as to quickly cool the post-reaction logistics.

[0097] 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.

[0098] 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, preferably at a position where the catalyst density drops to 70% to 30% of the catalyst density in the dense fluidized bed, 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.

[0099] 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.

[0100] 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 post-reaction stream exceeds 530°C after the cooling step in the cooling zone, 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 post-reaction stream after the cooling step in the cooling zone is lower than 450°C, the energy consumption of the cooling zone will be increased, and the energy consumption required for subsequent catalyst regeneration will also increase.

[0101] 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.

[0102] 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.

[0103] In one embodiment of the present invention, in the first catalytic conversion reactor, the catalyst density of the catalyst in the dense phase fluidized bed is 100-700 kg / m 3 , preferably 300-600kg / m 3 , more preferably 400-500kg / m 3 If the density of the catalyst is too low, the contact between the reaction raw materials and the catalyst is insufficient, and the reaction raw materials are prone to thermal cracking reactions. 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.

[0104] In one embodiment of the present invention, the conditions for the catalytic conversion reaction include: a reaction temperature of 550-800°C, preferably 600-700°C, and more preferably 650-700°C.

[0105] In one embodiment of the present invention, the reaction time of the catalytic conversion reaction is 0.1-20 s, preferably 0.1-10 s, more preferably 0.1-5 s, and particularly preferably 0.2-0.5 s.

[0106] In one embodiment of the present invention, the reaction pressure of the catalytic conversion reaction is 0.05-2 MPa, preferably 0.1-1 MPa, and more preferably 0.1-0.6 MPa.

[0107] 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, more preferably (5-50):1, and particularly preferably (12-30):1.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] In one embodiment of the present invention, the ratio of the diameter to the height of the dense phase fluidized bed section is (0.1-20):1, preferably (0.1-10):1.

[0113] 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.

[0114] 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.

[0115] In one embodiment of the present invention, a raw material inlet is provided on the side wall of the expanded diameter section.

[0116] In one embodiment of the present invention, a gas-solid mixed fluid distributor is further provided at the tail of the first lifting section.

[0117] 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.

[0118] 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 flow containing reaction oil and gas containing light olefins and the first catalyst to be generated is transported to the separation system for gas-solid separation. The diameter of the pipeline can be determined according to the specific situation.

[0119] 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;

[0120] In one embodiment of the present invention, the molecular sieve is at least one selected from the group consisting of a ZSM-5 series molecular sieve and a SAPO series molecular sieve; preferably a medium-pore ZSM-5 series molecular sieve, and more 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.

[0121] In one embodiment of the present invention, the silicon to aluminum ratio of the molecular sieve is 10-1000.

[0122] In one embodiment of the present invention, the inorganic oxide is one or more selected from silicon dioxide and aluminum oxide.

[0123] 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.

[0124] In one embodiment of the present invention, the hydrocarbon feedstock is a gaseous feed.

[0125] 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.

[0126] 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.

[0127] 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%.

[0128] 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.

[0129] 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).

[0130] 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.

[0131] 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.

[0132] 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 and propylene) 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 reaction oil gas containing the light olefins.

[0133] 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 reaction oil and gas containing light olefins and the first catalyst to be regenerated to obtain reaction oil and 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 reaction oil and gas containing light olefins to obtain the light olefins of the present invention.

[0134] In addition, in one embodiment of the present invention, the hydrocarbon stream (olefin-rich component) obtained by the separation means is refluxed as a hydrocarbon feedstock.

[0135] In the present invention, the hydrocarbon feedstock catalytic cracking process and the heavy oil catalytic cracking process of the present invention can also be coupled, thereby being used to produce a variety of target products, and being able to give full play to the respective advantages of the processes for producing light olefins from different feedstocks, thereby increasing the yield and selectivity of light olefins and improving the utilization rate of petroleum resources.

[0136] Therefore, the method of the present invention may further comprise the steps of:

[0137] 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 reactant stream comprising a reaction oil gas containing light oil and a second spent catalyst;

[0138] The second reactant stream comprising the reaction oil gas containing light oil and the second catalyst to be spent 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 reaction oil gas containing light olefins and the reaction oil gas containing light oil) and a mixed spent catalyst (a mixture of the first catalyst to be spent and the second catalyst to be spent);

[0139] The mixed reaction flow containing light olefins is fractionated to separate dry gas, light olefins and C4 and above distillate oil, the C4 and above distillate oil is subjected to a second separation and the separated olefin-rich component (hydrocarbon feed stream) is returned to the first catalytic conversion reactor; 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.

[0140] In one embodiment of the present invention, the heavy hydrocarbon oil is at least one 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.

[0141] In one embodiment of the present invention, the conditions for 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 0.01-80s, preferably 0.1-60s.

[0142] In one embodiment of the present invention, the weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-50):1.

[0143] In one embodiment of the present invention, a second cooling zone is provided downstream of the reaction zone of the second catalytic conversion reactor, and when the temperature of the second reactant flow comprising the reaction oil gas containing light oil and the second spent catalyst exceeds 530°C in the second catalytic conversion reactor, the second reactant flow is cooled to below 530°C.

[0144] 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.

[0145] 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.

[0146] 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,

[0147] 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;

[0148] Wherein, the cooling zone is arranged downstream of the dense 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 fluidized bed layer, and is preferably arranged at a position where the catalyst density is reduced to 70% to 30% of the catalyst density in the dense fluidized bed layer.

[0149] 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.

[0150] 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 (0.1-20):1, preferably (0.1-10):1.

[0151] 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.

[0152] 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.

[0153] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, a feedstock inlet is provided on the side of the expanded diameter section.

[0154] 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.

[0155] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the cooling zone is provided with a fluid distributor for introducing a cooling medium, and the fluid distributor is arranged in an annular shape along the circumference of the catalytic conversion reactor.

[0156] 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.

[0157] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the dense phase fluidized bed section is provided with an immediate heat replenishment system, and the immediate heat replenishment system includes a catalyst replenishment pipe for introducing hot catalyst into the dense phase fluidized bed section.

[0158] In one embodiment of the present invention, in the system for producing light olefins from hydrocarbon feedstocks, the dense phase fluidized bed section is provided with an immediate heat supplement system, and the immediate heat supplement system includes a heat supplier provided in the dense phase fluidized bed section.

[0159] 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.

[0160] 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 reaction 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] The top outlet of the second catalytic conversion reactor is connected to the inlet of the settler,

[0166] 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.

[0167] It should be noted that, unless otherwise specified, the reaction pressure in the present invention refers to absolute pressure.

[0168] 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.

[0169] FIG1 shows a first catalytic conversion reactor according to a specific embodiment of the present invention. The first catalytic conversion reactor of the present invention will be described in detail below with reference to FIG1. ​​A pre-lifting medium enters the first lifting section 2 through pipeline 1, and the first hot regenerated catalyst from the regeneration inclined tube 3 ascends under the action of the pre-lifting medium. The preheated hydrocarbon feedstock is introduced from the first lifting section through the feed pipeline 4 and distributed by the gas-solid mixed fluid distributor 5 before entering the reaction zone 11 of the first catalytic conversion reactor. In the reaction zone 11, the hydrocarbon feedstock contacts the first hot regenerated catalyst in the form of a dense phase fluidized bed to perform a first catalytic conversion reaction, thereby obtaining a first reaction flow comprising reaction oil and gas containing light olefins and a first catalyst to be regenerated. The cooling medium from other sections is introduced through pipeline 12 and enters the cooling zone 14 through the annular fluid distributor 13 to cool the first reaction flow after the reaction. The reaction flow is cooled to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably within 0.5-1 second). The cooled first reaction flow is accelerated by the second lifting section 17 and then enters the subsequent catalyst separation device and the separation device of the reaction oil and gas containing light olefins through the horizontal pipe 18.

[0170] FIG2 shows a first catalytic conversion reactor according to another specific embodiment of the present invention. The first catalytic conversion reactor of the present invention will be described in detail below with reference to FIG2. The pre-lifting medium enters the first lifting section 2 through the pipeline 1, and the first hot regeneration catalyst from the regeneration inclined tube 3 ascends under the action of the pre-lifting medium and enters the reaction zone 11 of the first catalytic conversion reactor after being distributed by the gas-solid mixed fluid distributor 5. The preheated hydrocarbon feedstock is introduced through the side pipeline 10 of the first catalytic conversion reactor. Under the distribution action of the feed fluid distributor 8, the hydrocarbons are fully contacted with the first hot regeneration catalyst in the form of a dense phase fluidized bed to carry out the first catalytic conversion reaction, thereby obtaining a first reaction flow comprising reaction oil and gas containing low-carbon olefins and the first catalyst to be regenerated. The cooling medium from other sections is introduced into the heat exchanger 15 provided in the cooling zone 14 through the pipeline 16. The first reaction flow after the reaction contacts the heat exchanger for cooling. The reaction flow is cooled to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably within 0.5-1 second). The cooled first reaction flow is accelerated by the second lifting section 17 and then enters the subsequent catalyst separation device and the separation device of the reaction oil and gas containing light olefins through the horizontal pipe 18.

[0171] FIG3 shows a first catalytic conversion reactor according to a specific embodiment of the present invention. The first catalytic conversion reactor of the present invention will be described in detail below with reference to FIG3. The pre-lifting medium enters the first lifting section 2 through pipeline 1, and the first hot regenerated catalyst from the regeneration inclined tube 3 ascends under the action of the pre-lifting medium, and then enters the reaction zone 11 of the first catalytic conversion reactor through the distribution action of the gas-solid mixed fluid distributor 5. The hydrocarbon feedstock is introduced into the reactor through the side pipeline 10 of the first catalytic conversion reactor, and enters the reaction zone under the action of the feed fluid distributor 8, and contacts the first hot regenerated catalyst in the form of a dense phase fluidized bed to undergo catalytic cracking reaction, thereby obtaining a first reaction flow containing reaction oil and gas containing light olefins and the first catalyst to be regenerated. At the same time, the additional first hot regenerated catalyst from the regenerator enters the reaction zone from the bottom of the reaction zone of the first catalytic conversion reactor through pipeline 7 to supplement heat for the dense phase fluidized bed. Cooling medium from other sections is introduced through pipeline 12 and enters cooling zone 14 via annular fluid distributor 13, cooling the first reactant stream after reaction to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably 0.5-1 second). The cooled first reactant stream is accelerated through second riser 17 and then enters the subsequent catalyst separation system and the separation device for the reaction oil and gas containing light olefins through horizontal pipe 18.

[0172] In another specific embodiment, as shown in FIG4 , the pre-lifting medium enters the first lifting section 2 through pipeline 1, and the first hot regenerated catalyst from the regeneration inclined tube 3 ascends under the action of the pre-lifting medium. The preheated hydrocarbon feedstock is introduced into the first lifting section through pipeline 4, and then enters the reaction zone 11 of the first catalytic conversion reactor through the distribution action of the gas-solid mixed fluid distributor 5. In the reaction zone 11, the hydrocarbon feedstock contacts the first hot regenerated catalyst in the form of a dense fluidized bed to undergo a catalytic conversion reaction, thereby obtaining a first reaction flow containing reaction oil and gas containing light olefins and the first catalyst to be regenerated. The dense fluidized bed section in the reaction zone 11 of the first catalytic conversion reactor is provided with a heater 9, and the heating medium is introduced into the heater 9 through pipeline 6 to supplement heat for the dense fluidized bed. Cooling medium from other sections is introduced through pipeline 12 and enters cooling zone 14 via annular fluid distributor 13, cooling the first reactant stream after reaction to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably 0.5-1 second). The cooled first reactant stream is accelerated through second riser 17 and then enters the subsequent catalyst separation system and the separation device for the reaction oil and gas containing light olefins through horizontal pipe 18.

[0173] In another specific embodiment of the present invention, as shown in FIG5 , the pre-lifting medium enters the first lifting section 2 through pipeline 1, and the first hot regenerated catalyst from the regeneration inclined tube 3 ascends under the action of the pre-lifting medium, and then enters the reaction zone 11 of the first catalytic conversion reactor through the distribution action of the gas-solid mixed fluid distributor 5. The hydrocarbon feedstock is introduced from the first lifting section through pipeline 4, and then enters the reaction zone 11 of the first catalytic conversion reactor, and enters the reaction zone under the action of the gas-solid mixed fluid distributor (not shown) to contact the first hot regenerated catalyst in the form of a dense phase fluidized bed to undergo catalytic cracking reaction, thereby obtaining a first reaction flow containing reaction oil and gas containing light olefins and the first catalyst to be regenerated. The heating medium from other sections enters the heater 9 (not shown) through pipeline 6 to supplement the heat for the dense phase fluidized bed. The cooling medium from other sections is introduced through pipeline 12 and passes through the fluid distributor and enters the cooling zone 14 to cool the first reaction flow after the reaction. The reaction flow is cooled to 450-530°C (preferably 480-500°C) within 0.5-2 seconds (preferably within 0.5-1 second). The first reaction flow after cooling treatment is accelerated by the second lifting section 27 and enters the catalyst separation device. In the catalyst separation device, the reacted flow enters the cyclone separator of the settler 28 to separate the first spent catalyst and the reaction oil and gas containing light olefins; after settling, the first spent catalyst flows to the stripping section 25 and contacts the stripping steam from pipeline 24 to strip out the remaining reaction oil and gas on the first spent catalyst. The first spent catalyst after stripping enters the regenerator 31 through pipeline 26 for char regeneration. The regenerated first catalyst returns to the first catalytic conversion reactor through pipeline 3.

[0174] The reaction oil and gas containing light olefins separated by the cyclone separator enters the gas collecting chamber 29, and then enters the distillation tower 33 through pipeline 30 for the first separation. The separated hydrogen, methane and ethane are drawn out through pipeline 34, ethylene is drawn out through pipeline 35, propylene is drawn out through pipeline 36, butene is drawn out through pipeline 37, propane and butane are drawn out through pipeline 38, and the other components enter the alkane-olefin separation unit 40 through pipeline 39 for the second separation. The separated olefin-free stream is sent to the alkane processing unit through pipeline 41, and the olefin-containing fraction is mixed with the hydrocarbon feedstock from pipeline 43 through pipeline 42 and returned to the first reactor to continue participating in the reaction.

[0175] In the present invention, the catalyst separation device and the separation device for reaction oil and gas containing light olefins in FIG. 5 of the present invention are applicable to other embodiments of the present invention, such as the embodiments in FIG. 1-4 .

[0176] In another embodiment of the present invention, the catalytic cracking process of the heavy feedstock can be coupled with the catalytic conversion process of the hydrocarbon feedstock described above, as shown in Figure 6. A pre-lifting medium enters the first lifting section 2 via pipeline 1. The first hot regenerated catalyst from the regeneration inclined tube 3 ascends under the action of the pre-lifting medium and then enters the reaction zone 11 of the first catalytic conversion reactor via the distribution action of a gas-solid mixed fluid distributor 5 (not shown). The hydrocarbon feedstock is introduced into the first reactor via a side pipeline 10 of the first catalytic conversion reactor. Under the action of the gas-solid mixed fluid distributor 5 (not shown), it enters the reaction zone of the first catalytic conversion reactor and contacts the first hot regenerated catalyst in the form of a dense phase fluidized bed, undergoing a catalytic cracking reaction, producing a first reactant stream comprising reaction oil and gas containing light olefins and the first regenerated catalyst. The hot regenerated catalyst from the regenerator enters the first catalytic conversion reactor via pipeline 7, replenishing heat for the dense phase fluidized bed. The reacted first reactant stream is cooled in a cooling zone 14 by a cooling medium from pipeline 12 and enters the catalyst separation device via a second lifting section 17.

[0177] The pre-lifting medium enters the first lifting section 22 through pipeline 20, and moves upward together with the second regenerated catalyst from pipeline 32, and enters the second catalytic conversion reactor together with the heavy raw material from pipeline 21, and contacts the second hot regenerated catalyst to undergo catalytic conversion reaction in the reaction zone of the second catalytic conversion reactor. The second reaction flow obtained by the reaction, which contains reaction oil gas containing light oil and the second catalyst to be regenerated, is cooled by the cooling medium from pipeline 44 when the temperature is higher than 530°C, and then enters the catalyst separation device through the outlet section 27.

[0178] Within the catalyst separation unit, the post-reaction first stream from the first catalytic converter is mixed with the second reaction stream from the second catalytic converter, then enters the cyclone separator of settler 28 to separate the mixed spent catalyst (a mixture of the first spent catalyst and the second spent catalyst) from the mixed reaction oil and gas (a mixture of reaction oil and gas containing light olefins and reaction oil and gas containing light oil). After settling, the mixed spent catalyst flows to stripping section 25, where it comes into contact with stripping steam from pipeline 24. It then enters regenerator 31 via pipeline 26 for char regeneration. The resulting regenerated catalyst is returned to the first catalytic converter as the first regenerated catalyst and to the second catalytic converter as the second regenerated catalyst via pipeline 3 and pipeline 32, respectively. Furthermore, high-temperature regenerated catalyst is provided to the dense-phase fluidized bed section via pipeline 7.

[0179] The separated mixed reaction oil and gas enters the gas collecting chamber 29 and is introduced into the distillation tower 33 through pipeline 30 for the first separation. The separated hydrogen, methane and ethane are led out through pipeline 34, ethylene is led out through pipeline 35, propylene is led out through pipeline 36, butene is led out through pipeline 37, propane and butane are led out through pipeline 38, and the other components enter the alkane-olefin separation device 40 through pipeline 39 for the second separation. The separated olefin-free logistics is sent to the alkane processing system through pipeline 41, and the olefin-containing fraction is mixed with the hydrocarbon feedstock from pipeline 43 through pipeline 42 and then enters the first reactor to continue the reaction.

[0180] The present invention also provides the following specific implementation methods.

[0181] A method for producing light olefins from hydrocarbon feedstocks, characterized in that the method comprises the following steps:

[0182] The olefin-rich raw material is injected into a dense phase fluidized bed with an instant heat replenishment system and a density of 100-700 kg / m 3 The hot regenerated catalyst contacts and undergoes a catalytic conversion reaction at a reaction temperature of 550-800°C. After the reacted 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 to obtain reaction oil and gas and regenerated catalyst; the regenerated catalyst enters the regenerator after stripping, and the reaction oil and gas are separated into products such as ethylene and propylene.

[0183] Optionally, the cooling zone is provided with a plurality of fluid distributors for introducing the cooling medium, and the fluid distributors are arranged in an annular shape along the circumference of the catalytic conversion reactor, or the cooling zone is provided with a plurality of heat extractors arranged along the circumference of the tail of the catalytic conversion reactor;

[0184] The cooling medium is a coolant and / or a cooled regenerated catalyst; the coolant is selected from at least one of liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel, water, and olefins with eight or more carbon atoms. The above coolant can also be used as a second raw material to undergo cracking reaction in the cooling zone, absorbing heat to quickly cool the reaction materials in the reaction zone.

[0185] Optionally, the instant heat replenishment system includes a catalyst replenishment pipe for introducing additional hot regenerated catalyst into the dense fluidized bed, or the instant heat replenishment system includes a heat supplier arranged in the dense fluidized bed of the reactor; the heating medium in the heat supplier is at least one of high-temperature steam and steam cracking gas.

[0186] Optionally, the reacted logistics is cooled to the target temperature within 0.5-2 seconds, preferably within 0.5-1 second.

[0187] Optionally, the catalyst density of the thermally regenerated catalyst in the dense phase fluidized bed of the catalytic conversion reactor is 100-700 kg / m 3 , preferably 300-600kg / m 3 , more preferably 400-500kg / m 3 .

[0188] Optionally, the conditions of the catalytic conversion reaction include: a reaction temperature of 550-800°C, preferably 600-700°C, and more preferably 650-700°C; a reaction time of 0.1-20s, preferably 0.1-10s, and more preferably 0.2-0.5s; a reaction pressure of 0.05-2MPa, preferably 0.1-0.6MPa; and a weight ratio of the thermally regenerated catalyst to the olefin-rich raw material of (1-200):1, preferably (10-100):1.

[0189] Optionally, the catalytic conversion 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 (0.1-10):1; the angle between the side wall of the reduction section and the axis is 5-60 degrees;

[0190] The head of the first lifting section is provided with a heat regeneration catalyst inlet and a lifting medium inlet;

[0191] A raw material inlet is provided in the middle of the first lifting section;

[0192] A gas-solid mixed fluid distributor is also provided at the tail of the first lifting section;

[0193] The cooling zone is arranged at the tail end of the dense phase fluidization section.

[0194] Optionally, based on the total weight of the thermally regenerated catalyst, the thermally regenerated catalyst comprises 1-50 wt% of molecular sieve, 5-99 wt% of inorganic oxide and 0-70 wt% of clay;

[0195] The molecular sieve is selected from at least one of the ZSM-5 series molecular sieve and the SAPO series molecular sieve; preferably the medium-pore ZSM-5 series molecular sieve;

[0196] The silicon to aluminum ratio of the molecular sieve is 10-1000;

[0197] The inorganic oxide is selected from one or more of silicon dioxide and aluminum oxide; the clay is selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

[0198] Optionally, the olefin-rich raw material is a gaseous feed; the content of C5-C8 olefins in the olefin-rich raw material is 50-100 wt%, preferably 80-100 wt%, more preferably 90-100 wt%;

[0199] Preferably, the olefin-rich raw material 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 fraction produced as a by-product of MTO, and the C5 and above olefin-rich fraction produced as a by-product of MTP.

[0200] Optionally, the method further comprises the steps of: performing gas-solid separation on the post-reaction logistics to obtain reaction oil gas and spent catalyst, and then performing a char regeneration treatment on the spent catalyst and returning it to the catalytic conversion reactor;

[0201] Optionally, the method further comprises the following steps: naming the catalytic conversion reactor and catalyst as the first reactor and the first catalyst. Contacting the heavy hydrocarbon oil with the second thermally regenerated catalyst in the second catalytic conversion reactor to perform a second catalytic conversion reaction to obtain a reaction oil gas containing light oil and a second regenerated catalyst; when the temperature of the reaction oil gas containing light oil and the second regenerated catalyst in the upper region of the reaction zone of the second catalytic conversion reactor exceeds 530° C., providing a cooling zone downstream of the reaction zone to cool the reaction oil gas containing light oil and the second regenerated catalyst to below 530° C.;

[0202] Then, the cooled reaction oil gas containing light oil, the second spent catalyst and the post-reaction stream are mixed, and the mixed stream is subjected to a first separation to obtain a reaction stream containing light olefins and a spent catalyst;

[0203] The reaction stream containing light olefins is distilled to separate dry gas, light olefins and C4 and above distillate oil, the C4 and above distillate oil is subjected to a second separation and the separated olefin-rich component is returned to the first catalytic conversion reactor; and the spent catalyst is charred and regenerated and the regenerated catalyst is returned to the first catalytic conversion reactor and the second catalytic conversion reactor.

[0204] Optionally, the heavy hydrocarbon oil is selected from at least one 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;

[0205] 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 0.01-80s, preferably 0.1-60s; the weight ratio of the second thermally regenerated catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-50):1.

[0206] Example

[0207] 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 can all be obtained through commercial sources. The catalyst used is of the trade name TCC-1, produced by the Qilu Branch of Sinopec Catalyst Co., Ltd. The heavy hydrocarbon oil feedstock used is heavy oil I, and the properties of heavy oil I are shown in Table 1.

[0208] Table 1

[0209] Example 1

[0210] The experiments in this embodiment were conducted in a dense-phase fluidized bed catalytic converter (first catalytic converter reactor) shown in FIG1 , wherein the reaction feedstock was 1-pentene and the catalyst was TCC-1. Specific parameters of the fluidized bed catalytic converter include: a total height of 11.5 meters for the first riser, expansion section, dense-phase fluidized bed section, cooling zone, reduction section, and second riser, wherein the first riser had a diameter of 0.5 meters and a height of 1.5 meters; the sidewall of the expansion section had an angle of 45 degrees with the axis, and the expansion section had a height of 1 meter; the dense-phase fluidized bed section had a diameter of 2.5 meters and a height of 5 meters; the sidewall of the reduction section had an angle of 45 degrees with the axis, and a height of 1.0 meter; the second riser had a diameter of 0.5 meters and a height of 3 meters; and the cooling zone was located at a position where the catalyst density dropped to 70% of the catalyst density in the dense-phase fluidized bed.

[0211] The raw material 1-pentene enters the first catalytic conversion device through the feed pipeline at the bottom of the reaction zone, then enters the reaction zone through the gas-solid mixed fluid distributor, and contacts with the TCC-1 catalyst in the form of a dense phase fluidized bed at a temperature of about 650°C to carry out the first catalytic conversion reaction. The weight ratio of the catalyst TCC-1 to the raw material 1-pentene is 30:1, and the catalyst density in the reaction zone is 400 kg / m 3 , downstream of the reactant flow, the density of the catalyst is reduced to 280 kg / m 3 A cooling zone was set up at the position of the reaction chamber, using water as the cooling medium to rapidly cool the post-reaction stream, reducing its temperature to 500°C within 1.0 second. The cooled first reaction stream was accelerated by second riser 17 and then passed through horizontal pipe 18 into the subsequent catalyst separation unit and the separation unit for the reaction oil and gas containing light olefins. The reaction conditions and product distribution are shown in Table 2.

[0212] Comparative Example 1

[0213] This comparative example was conducted in the dense-phase fluidized bed catalytic converter (first catalytic converter reactor) shown in Figure 1 , where the reaction feedstock was 1-pentene and the catalyst was TCC-1. This comparative example differs from Example 1 in the structure of the fluidized bed catalytic converter reactor: the total height of the first riser, expansion section, dense-phase fluidized bed section, reduction section, and second riser section of the fluidized bed catalytic converter is 15.5 meters. The first riser section has a diameter of 0.5 meters and a height of 1.5 meters; the sidewall of the expansion section is at an angle of 45 degrees to the axis, and the height of the expansion section is 0.5 meters; the diameter of the dense-phase fluidized bed section is 1.5 meters and the height is 10 meters; the sidewall of the reduction section is at an angle of 45 degrees to the axis, and the height of the reduction section is 0.5 meters; and the diameter of the second riser section is 0.5 meters and the height is 3 meters. No cooling zone is provided.

[0214] The raw material 1-pentene enters the first catalytic conversion device through the feed pipeline at the bottom of the reaction zone, and then enters the reaction zone through the gas-solid mixed fluid distributor, where it contacts the TCC-1 catalyst in the form of a dense phase fluidized bed at a temperature of about 650°C for the first catalytic conversion reaction. The catalyst density in the reaction zone is 90kg / m 3 , and no cooling medium was injected at the outlet. The weight ratio of catalyst TCC-1 to raw material 1-pentene was 30:1. The operating conditions and product distribution are shown in Table 2.

[0215] Table 2

[0216] Example 2

[0217] This embodiment was tested on a medium-sized dense fluidized bed catalytic converter (first catalytic converter reactor) according to the process shown in Figure 2. The reaction raw material was 1-octene and the catalyst was TCC-1. The structural parameters of the first catalytic converter reactor include:

[0218] The total height of the first lifting section, the expansion section, the dense fluidized bed section, the cooling zone, the reduction section and the second lifting section is 11.5 meters, among which the diameter of the first lifting section is 0.25 meters and the height is 1.5 meters; the angle between the side wall of the expansion section and the axis is 45 degrees, and the height of the expansion section is 1 meter; the diameter of the dense fluidized bed section is 2.5 meters and the height is 5 meters; the angle between the side wall of the reduction section and the axis is 45 degrees, and the height is 1.0 meter; the diameter of the second lifting section is 0.5 meters and its height is 3 meters. The cooling zone is arranged at a position where the catalyst density is reduced to 80% of the catalyst density in the dense fluidized bed layer.

[0219] The raw material 1-octene enters the first catalytic conversion reactor from the feed pipeline at the bottom of the reaction zone, enters the reaction zone through the gas-solid mixed fluid distributor, and contacts with the TCC-1 catalyst in the form of a dense phase fluidized bed in the reaction zone for catalytic cracking reaction. The weight ratio of the catalyst TCC-1 to 1-octene is 30:1, and the catalyst density in the reaction zone is 400 kg / m 3 The reaction temperature is 600℃, the reaction pressure is 0.2MPa, the reaction time is 0.5s, and the density of the catalyst is reduced to 320kg / m 3 A cooling zone was set up at the position where the post-reaction stream was cooled by the cooling medium in the heat exchanger. The temperature of the post-reaction stream dropped to 450°C within 1.5 seconds. The cooled first reactant stream was accelerated by the second riser 17 and then passed through horizontal pipe 18 into the subsequent catalyst separation unit and the separation unit for the reaction oil and gas containing light olefins. The reaction conditions and product distribution are shown in Table 3.

[0220] Comparative Example 2

[0221] This comparative example was tested in a medium-sized dense fluidized bed catalytic converter (catalytic conversion reaction) according to the process flow diagram shown in Figure 2. The reaction feedstock was 1-octene and the catalyst was TCC-1. The reaction flow diagram of Comparative Example 2 was similar to that of Example 2, except that a heat extractor was not provided for cooling.

[0222] The raw material 1-octene enters the first catalytic conversion reactor from the feed pipeline at the bottom of the reaction zone, enters the reaction zone through the gas-solid mixed fluid distributor, and contacts with the TCC-1 catalyst in the form of a dense phase fluidized bed to undergo catalytic cracking reaction. The reaction temperature is 600°C, the reaction pressure is 0.2MPa, the reaction time is 0.5s, and the catalyst density in the reaction zone is 400kg / m 3 , and no heat extractor was set. The weight ratio of catalyst TCC-1 to 1-octene was 30:1. The reaction conditions and product distribution are shown in Table 3.

[0223] Table 3

[0224] Example 3

[0225] This embodiment was tested in a dense-phase fluidized bed catalytic conversion reactor (first catalytic conversion reactor) shown in FIG3 , wherein the raw material was 1-hexene and the catalyst was TCC-1. The reaction raw material 1-hexene entered the fluidized bed catalytic conversion reactor through a side feed line 10 of the reaction zone, then entered the reaction zone through a feed fluid distributor. At 650° C., it came into contact with the TCC-1 catalyst in a dense-phase fluidized bed to cause a cracking reaction. The weight ratio of the catalyst to 1-hexene was 30:1, the reaction time was 0.5 s, and the catalyst density in the reaction zone was 400 kg / m 3 At the same time, a heat-regenerated catalyst TCC-1 with a temperature of 700°C is introduced into the bottom of the reactor to supplement the heat of the dense phase fluidized bed. In the downstream of the reactant flow, the density of the catalyst is reduced to 240 kg / m 3 A cooling zone is located at the position of the reactor. A cooling medium is introduced through an annular fluid distributor 13 to cool the post-reaction stream, reducing its temperature to 450°C within 1.5 seconds. The cooling medium in this zone is water. The cooled reactant stream is accelerated by a second riser 17 and then enters the subsequent catalyst separation unit and the separation unit for the reaction oil and gas containing light olefins through a horizontal pipe 18. The operating conditions and product distribution are shown in Table 4.

[0226] Example 4

[0227] This embodiment was tested in a fluidized bed catalytic conversion reactor (first catalytic conversion reactor) shown in FIG4 , wherein the raw material was 1-hexene and the catalyst was TCC-1. The reaction raw material 1-hexene entered the fluidized bed catalytic conversion reactor through the bottom feed line 4 of the reaction zone, then entered the reaction zone through the annular gas-solid mixed fluid distributor. At 650° C., it came into contact with the TCC-1 catalyst in the form of a dense phase fluidized bed to cause a cracking reaction. The weight ratio of the catalyst TCC-1 to 1-hexene was 30:1, the reaction time was 0.5 s, and the catalyst density in the reaction zone was 400 kg / m 3 Heat is supplied to the dense phase fluidized bed through heaters on both sides of the reaction zone. In the downstream of the reaction flow, the density of the catalyst is reduced to 240 kg / m 3 A cooling zone was set up at the position to cool the post-reaction stream. The cooling medium in this zone was water, reducing the temperature of the reactant stream to 450°C within 1.5 seconds. The cooled reactant stream was accelerated by the second riser 17 and then passed through horizontal pipe 18 into the subsequent catalyst separation unit and the separation unit for the reaction oil and gas containing light olefins. The operating conditions and product distribution are shown in Table 4.

[0228] Comparative Example 3

[0229] This comparative example was tested in a fluidized bed catalytic conversion reactor (first catalytic conversion reactor) shown in FIG3 , wherein the raw material was 1-hexene and the catalyst was TCC-1. The reaction raw material 1-hexene entered the fluidized bed catalytic conversion reactor through a side feed line in the reaction zone, entered the reaction zone through a feed fluid distributor, and contacted with the TCC-1 catalyst in a dense phase fluidized bed at 650° C. to cause a cracking reaction. The weight ratio of the catalyst TCC-1 to 1-hexene was 30:1, the reaction time was 0.5 s, and the catalyst density in the reaction zone was 400 kg / m 3 , and no supplementary heating and cooling zones are set. The operating conditions and product distribution are shown in Table 4.

[0230] Table 4

[0231] Example 5

[0232] This example was carried out in the fluidized catalytic conversion reactor shown in Figure 6. The reaction feedstock of the first catalytic conversion reactor was 1-hexene, the reaction feedstock of the second catalytic conversion reactor was heavy oil I, and the catalyst was TCC-1.

[0233] The raw material 1-hexene enters the first catalytic conversion reactor through a feed line on the side of the reaction zone of the first catalytic conversion reactor, then enters the first catalytic conversion reaction zone through an annular gas-solid mixed fluid distributor, and contacts with a TCC-1 catalyst in the form of a dense phase fluidized bed at 650°C to carry out the first catalytic conversion reaction. The weight ratio of the catalyst TCC-1 to the raw material 1-hexene is 30:1, and the catalyst density in the reaction zone is 400 kg / m 3 The reaction time is 0.5s. At the same time, a hot regenerated catalyst with a temperature of 700℃ is introduced into the bottom of the reactor to supplement the heat of the dense phase fluidized bed to obtain the first reaction flow. Downstream of the first reaction flow, the density of the catalyst is reduced to 280kg / m 3 A cooling zone is set at the position to cool the post-reaction flow, and the temperature of the reaction flow is reduced to 500°C within 1.0s. The cooling medium of the cooling zone is water. In the first catalytic conversion reactor.

[0234] Heavy oil I contacts the TCC-1 catalyst in the reaction zone of the second catalytic conversion reactor to undergo a catalytic conversion reaction to obtain a second reactant flow. The reaction temperature is 550°C, the reaction pressure is 0.2 MPa, and the reaction time is 5s. In the second catalytic conversion reactor, the weight ratio of the catalytic conversion catalyst TCC-1 to the heavy oil I is 10:1.

[0235] After the first reactant stream and the second reactant stream are combined, post-processing is performed to obtain light olefins.

[0236] The reaction conditions and product distribution are shown in Table 5.

[0237] Comparative Example 4

[0238] This comparative example was carried out in the catalytic conversion reaction apparatus shown in Figure 6. The reaction feedstock of the first catalytic conversion reactor was 1-hexene, the reaction feedstock of the second catalytic conversion reactor was heavy oil I, and the catalyst was TCC-1.

[0239] The difference from Example 5 is that the thermally regenerated TCC-1 catalyst is not injected into the bottom of the first catalytic conversion reactor, and no cooling zone is provided at the top. The reaction conditions and product distribution are shown in Table 5.

[0240] Table 5

[0241] In summary, from the data of Table 2, Table 3, Table 4 and Table 5, it can be seen that the method provided by the present invention can significantly increase the content of light olefins in the product of the hydrocarbon feedstock cracking reaction by increasing the catalyst bed density and shortening the reactant residence time; by introducing a cooling medium at a specific position or through the effect of the cooling medium in the heat extractor, the temperature of the material after the reaction is quickly reduced, which can significantly inhibit the occurrence of side reactions such as thermal cracking and secondary reactions; by supplementing heat to the reaction zone of the fluidized bed catalytic conversion reaction device, the polymerization reaction of the olefin feedstock under low temperature conditions is suppressed to a certain extent, the production of large molecular olefin products is reduced, and the selectivity and yield of light olefin products, especially ethylene, propylene and other high value-added products, are improved. In addition, by coupling the heavy feedstock cracking process with the hydrocarbon feedstock cracking process, the entire process flow is also optimized, and the utilization efficiency of petroleum resources is improved.

[0242] 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.

[0243] 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.

[0244] 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 method for producing light olefins from hydrocarbon feedstocks, characterized in that: The method comprises the following steps: The catalyst density in the first catalytic conversion reactor is 100-700 kg / m 3 In a dense phase fluidized bed, the hydrocarbon feedstock is contacted with the first catalyst and a catalytic conversion reaction occurs at a reaction temperature of 550-800° C. to obtain a first reaction stream containing reaction oil gas containing light olefins and a first catalyst to be produced, and then the first reaction stream is cooled to 450-530° C. in a cooling zone. Then, light olefins are separated from the first reaction stream, 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 method according to claim 1, wherein: In the cooling zone, Using a cooling medium to cool down; the cooling medium is a coolant and / or a cooled catalyst; the coolant is at least one selected from liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel, water and olefins having eight or more carbon atoms; or A heat collector is used for cooling; the coolant in the heat collector is at least one selected from liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel, water and olefins with more than eight carbon atoms.

3. The method according to claim 1 or 2, wherein: During the reaction, heat is supplemented to the dense phase fluidized bed; preferably, the heat supplement is performed using a heating medium and / or a hot catalyst; the heating medium is at least one of high temperature steam and steam cracking gas.

4. The method according to any one of claims 1 to 3, wherein: In the cooling zone, the first reactant stream is cooled to 450-530° C., preferably 480-500° C., within 0.5-2 seconds, preferably within 0.5-1 second.

5. The method according to any one of claims 1 to 4, wherein: The catalyst density of the first catalyst in the dense phase fluidized bed of the first catalytic conversion reactor is 300-600 kg / m 3 , preferably 400-500kg / m 3 .

6. The method according to any one of claims 1 to 5, wherein: The conditions of the catalytic conversion reaction include: reaction temperature of 600-700°C, preferably 650-700°C; reaction time of 0.1-20s, preferably 0.1-10s, more preferably 0.2-5s, particularly preferably 0.2-0.5s; reaction pressure of 0.05-2MPa, preferably 0.1-1MPa, more preferably 0.1-0.6MPa; The weight ratio of the catalyst to the hydrocarbon feedstock is (1-200):1, preferably (10-100):

1.

7. The method according to any one of claims 1 to 6, 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 fluidized bed section is (0.1-20):1, preferably (0.1-10):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 hot catalyst inlet and a lifting medium inlet; A raw material inlet is provided in the middle of the first lifting section, or a raw material inlet is provided on the side wall of the diameter expansion 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 fluidized bed section, at a position where the catalyst density drops to 80% to 20% of the catalyst density in the dense fluidized bed layer, preferably at a position where the catalyst density drops to 70% to 30% of the catalyst density in the dense fluidized bed layer.

8. The method according to any one of claims 1 to 7, 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 of a ZSM-5 series molecular sieve and a SAPO series molecular sieve; preferably a medium-pore ZSM-5 series molecular sieve; further 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 one or more selected from silicon dioxide and aluminum oxide; and / or The clay is one or more selected from kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

9. The method according to any one of claims 1 to 8, 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 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 MTO, and a C5 or higher olefin-rich fraction produced as a by-product of MTP.

10. The method according to any one of claims 1 to 9, wherein: The method further comprises the steps of: performing gas-solid separation on the first reaction stream after cooling to obtain reaction oil gas containing light olefins and a first spent catalyst, performing a charring regeneration treatment on the first spent catalyst and returning it to the first catalytic conversion reactor as a first regenerated catalyst; Fractionating the reaction oil gas containing light olefins to obtain light olefins and an olefin-rich stream; The olefin-rich stream is refluxed as a hydrocarbon feedstock.

11. The method according to any one of claims 1 to 10, 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 stream containing a reaction oil gas containing light oil and a second catalyst to be spent; Mixing the second reaction flow containing the reaction oil gas containing light oil and the second spent catalyst with the first reaction flow, and performing a first separation on the mixed flow to obtain a mixed reaction flow 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 olefin-rich stream is returned to the first catalytic conversion reactor; and the mixed catalyst to be spent is regenerated by charring, 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.

12. The method according to claim 11, wherein: The heavy hydrocarbon oil is at least one 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 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 0.01-80s, preferably 0.1-60s; and / or The weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-50):

1.

13. The method according to claim 11 or 12, wherein: A second cooling zone is arranged downstream of the reaction zone of the second catalytic conversion reactor, and when the temperature of the second reaction flow containing the 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.

14. 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 (0.1-20):1, preferably (0.1-10):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; or a raw material inlet is provided on the side wall of the diameter expansion 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 fluidized bed section, at a position where the catalyst density drops to 80% to 20% of the catalyst density in the dense fluidized bed layer, preferably at a position where the catalyst density drops to 70% to 30% of the catalyst density in the dense fluidized bed layer.

15. The system of claim 14, wherein: The cooling zone is provided with a fluid distributor for introducing a cooling medium, and the fluid 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.

16. The system according to claim 14 or 15, wherein: The dense phase fluidized bed section is provided with an immediate heat supplement system, and the immediate heat supplement system comprises a catalyst supplement pipe for introducing hot catalyst into the dense phase fluidized bed section, or The instant heat supplement system includes a heat supplier arranged in the dense phase fluidized bed section.

17. The system according to any one of claims 14 to 16, 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 communicated with the inlet of the settler, the catalyst outlet of the settler is communicated with the regenerator, the reaction 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.

18. The system of any one of claims 14-17, 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 in communication with the catalyst inlet of the first catalytic conversion reactor and the catalyst inlet of the second catalytic conversion reactor.

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