Catalytic conversion method for preparing low-carbon olefins

Abstract

The invention relates to a catalytic conversion method for preparing low-carbon olefins, which comprises the following steps of: contacting an olefin-rich raw material with a hot regenerated first catalyst in a dense-phase fluidized bed layer of a first reactor to carry out a first catalytic conversion reaction, carrying out instantaneous cooling on the reacted material flow through a cooling area at the downstream of the dense-phase fluidized bed layer, cooling the reacted material flow to a target temperature of 450-530 DEG C, separating, and sending out of the first reactor to obtain first reaction oil gas and a first spent catalyst; part of the first catalyst in the dense-phase fluidized bed layer is taken out from a slide valve at the bottom of the first reactor, so that the density of the first catalyst in the dense-phase fluidized bed layer is 100-700 kg / m < 3 >. The thermal cracking reaction can be obviously inhibited by rapidly cooling the material flow after the reaction and controlling the density of the catalyst in the bed layer of the dense-phase fluidized bed through the slide valve, and the yield of by-products is reduced while the yield of low-carbon olefins is increased.

Description

Technical Field

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

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

[0003] The typical process for producing low-carbon olefins at present is naphtha steam cracking, and the yield of ethylene and propylene is low, which is difficult to meet the growing market demand. In this regard, CN1490287A discloses a method for preparing low-carbon olefins using a hydrocarbon mixture containing C4 or C5 monoolefins as a raw material, wherein the hydrocarbon mixed raw material is contacted with a catalyst in a fixed bed reactor for reaction, but the yield of ethylene and propylene in the obtained product is low. CN114763483A discloses a method for preparing low-carbon olefins using a raw material rich in olefins, wherein the method first performs high-temperature cracking on a hydrocarbon oil raw material containing olefins, and then introduces the olefins in the separated product into a catalytic conversion reactor for continued reaction, so as to fully utilize butene and olefins above C5 to produce ethylene and propylene, and reduce the methane yield.

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

[0005] The object of the present invention is to provide a method for improving the yield of light olefins, which can increase the ethylene / propylene ratio in the light olefins and reduce the energy consumption of the reaction system.

[0006] In order to achieve the above object, the present invention provides a catalytic conversion method for preparing light olefins, which comprises the following steps:

[0007] The olefin-rich raw material is brought into contact with the hot regenerated first catalyst in the dense phase fluidized bed of the first reactor to carry out a first catalytic conversion reaction. The post-reaction logistics is instantaneously cooled in a cooling zone downstream of the dense phase fluidized bed, so that the post-reaction logistics is cooled to a target temperature of 450-530° C. and separated and then sent out of the first reactor to obtain a first reaction oil gas and a first catalyst to be regenerated; a portion of the first catalyst in the dense phase fluidized bed is taken out from a slide valve at the bottom of the first reactor so that the density of the first catalyst in the dense phase fluidized bed is 100-700 kg / m 3 .

[0008] Optionally, the first reactor includes, from bottom to top, a first lifting section, an expansion section, a dense phase fluidization section, a reduction section and a second lifting section; the angle between the side wall of the expansion section and the axis is 5-60 degrees; the ratio of the diameter to the height of the dense phase fluidization section is (1-20):1; the angle between the side wall of the reduction section and the axis is 5-60 degrees; the head of the dense phase fluidization section is also provided with a material distributor; the cooling zone is provided at the tail of the dense phase fluidization section; the cooling zone is provided with one or more coolant distributors, the reacted logistics is mixed with the coolant introduced through the coolant distributor, and is cooled to the target temperature within a preset time; the preset time is within 2 seconds, preferably within 1 second, and more preferably within 0.5 seconds; the coolant is selected from one or more of liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel and water.

[0009] Optionally, the density of the first catalyst in the dense phase fluidized bed is 300-650 kg / m 3 , more preferably 500-650kg / m 3 .

[0010] Optionally, the conditions of the first catalytic conversion reaction include: a reaction temperature of 550-800°C, preferably 580-750°C, and further preferably 600-700°C; a reaction pressure of 0.01-1MPa, preferably 0.1-0.8MPa, and further preferably 0.2-0.5MPa; a reaction time of 0.05-10 seconds, preferably 0.1-5 seconds, and further preferably 0.2-2 seconds; a weight ratio of the first catalyst to the olefin-rich feedstock of (5-50):1, preferably (10-35):1, and further preferably (12-30):1.

[0011] Optionally, the olefin content in the olefin-rich feedstock is 50-100 wt%, preferably 80-100 wt%; the olefin-rich feedstock is a gas phase feed; the olefin in the olefin-rich feedstock is C4-C 12 Olefins, preferably C4-C6 olefins.

[0012] Optionally, the first catalyst is a mesopore molecular sieve catalyst and / or a small pore molecular sieve catalyst; the mesopore molecular sieve catalyst is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48; the small pore molecular sieve catalyst is selected from one or more of SAPO-34, SAPO-11 and SAPO-47.

[0013] Optionally, the method further includes: stripping the first spent catalyst, then charring and regenerating the stripped first spent catalyst, and returning the regenerated first catalyst to the first reactor; or mixing the first spent catalyst with the regenerated first catalyst and returning them to the first reactor.

[0014] Optionally, the method also includes: contacting the heavy hydrocarbon oil with the second catalyst in the second reactor for a second catalytic conversion reaction to obtain a reaction oil gas containing light oil and a second catalyst to be regenerated; then mixing the reaction oil gas containing light oil with the first reaction oil gas, and performing a first separation on the mixed oil gas to obtain dry gas, light olefins and C5 and above distillate oil, performing a second separation on the C5 and above distillate oil and returning the separated olefin-rich component to the first reactor; stripping the second catalyst to be regenerated and regenerating the stripped second catalyst to be regenerated by charring, and then returning the regenerated second catalyst to the second reactor; and stripping the first catalyst to be regenerated and then transporting it to the regenerator for charring regeneration.

[0015] Optionally, the method further includes: mixing the first catalyst to be regenerated taken out through the sliding valve with the hot regenerated second catalyst to obtain a mixed catalyst; contacting the heavy hydrocarbon oil with the mixed catalyst in the second reactor for a second catalytic conversion reaction to obtain a reaction oil gas containing light oil and a catalyst to be regenerated; wherein, when the temperature of the reaction oil gas containing light oil and the catalyst to be regenerated in the upper area of ​​the reaction zone of the second reactor exceeds 530°C, a cooling zone is set downstream of the reaction zone, and the reaction oil gas containing light oil and the catalyst to be regenerated are cooled to below 530°C; stripping the catalyst to be regenerated, and charring and regenerating the stripped catalyst to be regenerated and returning them to the first reactor and the second reactor respectively; mixing the reaction oil gas containing light oil with the first reaction oil gas, and performing a first separation on the mixed oil gas to obtain dry gas, light olefins and C5 and above distillates, performing a second separation on the C5 and above distillates and returning the separated olefin-rich components to the first reactor.

[0016] Optionally, the heavy hydrocarbon oil is selected from one or more of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, heavy aromatic raffinate oil, coal liquefaction oil, oil sand oil and shale oil; the conditions of the second catalytic conversion reaction include: reaction temperature of 500-600°C, preferably 530-580°C; reaction pressure of 0.01-1MPa, preferably 0.05-1MPa; reaction time of 0.01-100s, preferably 0.1-80s; the weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-70):1.

[0017] Through the above technical scheme, the present invention can suppress thermal cracking reactions, increase the production of light olefins, and reduce the yield of by-products by rapidly cooling the post-reaction flow in the cooling zone, rapidly separating the gas and solid, and controlling the catalyst density in the dense phase fluidized bed layer through a slide valve to shorten the contact reaction time between the raw material and the first catalyst.

[0018] The present invention can not only flexibly adjust the density of the catalyst by taking out the first catalyst from the bottom of the reactor, but also save energy consumption for cooling the post-reaction logistics. Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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 specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 A schematic diagram of an embodiment of the first reactor provided by the present invention.

[0021] Figure 2 A schematic diagram of another embodiment of the first reactor provided by the present invention.

[0022] Figure 3 A schematic diagram of an embodiment of the method provided by the present invention.

[0023] Figure 4 A schematic diagram of another embodiment of the method provided by the present invention.

[0024] Figure 5 A schematic diagram of an embodiment of the catalytic conversion method provided by the present invention.

[0025] Figure 6 A schematic diagram of another embodiment of the catalytic conversion method provided by the present invention.

[0026] Description of Reference Numerals

[0027] A The first reactor B The second reactor

[0028] 1 pipeline 2 pipeline 3 material distributor

[0029] 4 pipelines 5 pipelines 6 pipelines

[0030] 7 slide valve 8 pipeline 9 stripping section

[0031] 10 second lifting section 11 horizontal pipe 12 settler

[0032] 13 cyclone separator 14 air collecting chamber 15 inclined pipe to be produced

[0033] 16 regenerator 17 pipeline 18 pipeline

[0034] 19 pipeline 20 large oil and gas pipeline 21 distillation tower

[0035] 22 pipeline 23 pipeline 24 pipeline

[0036] 25 pipeline 26 pipeline 27 pipeline

[0037] 28 pipeline 29 pipeline 30 olefin separation unit

[0038] 31 pipeline 32 pipeline 33 first lifting section

[0039] 34 cooling zone 35 coolant distributor 36 pipeline

[0040] 37 pipeline 38 pipeline DETAILED DESCRIPTION

[0041] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0042] The present invention provides a catalytic conversion method for preparing light olefins, the method comprising the following steps:

[0043] The olefin-rich raw material is brought into contact with the hot regenerated first catalyst in the dense phase fluidized bed of the first reactor to carry out a first catalytic conversion reaction. The post-reaction logistics is instantaneously cooled in a cooling zone downstream of the dense phase fluidized bed, so that the post-reaction logistics is cooled to a target temperature of 450-530° C. and separated and then sent out of the first reactor to obtain a first reaction oil gas and a first catalyst to be regenerated; a portion of the first catalyst in the dense phase fluidized bed is taken out from a slide valve at the bottom of the first reactor so that the density of the first catalyst in the dense phase fluidized bed is 100-700 kg / m 3 .

[0044] The present invention significantly inhibits thermal cracking reaction, increases the production of light olefins, and reduces the yield of by-products by rapidly cooling the post-reaction logistics in the cooling zone, rapidly separating gas and solid, and controlling the catalyst density in the dense phase fluidized bed layer by a slide valve to shorten the contact reaction time between the raw material and the first catalyst. The present invention can not only flexibly adjust the density of the catalyst by taking out the first catalyst from the bottom of the reactor, but also save energy consumption for cooling the post-reaction logistics.

[0045] The olefin-rich raw material is contacted with the hot regenerated first catalyst to carry out the first catalytic conversion reaction; the first catalyst is preheated and then introduced into the reactor to allow the raw material to undergo unimolecular cracking at a suitable temperature, which is beneficial to improving the yield of light olefins.

[0046] Preferably, the target temperature of the post-reaction logistics is reduced to 450-530°C, which can more significantly inhibit the thermal cracking reaction and over-cracking reaction of the post-reaction logistics, improve product distribution, and increase the production of light olefins. Specifically, the target temperature can be 450°C, 470°C, 490°C, 510°C, 520°C, 530°C or any value within the aforementioned range.

[0047] Among them, the first reactor includes, from bottom to top, a first lifting section, an expansion section, a dense phase fluidization section, a reduction section and a second lifting section; the angle between the side wall of the expansion section and the axis is 5-60 degrees; the ratio of the diameter to the height of the dense phase fluidization section is (1-20): 1; the angle between the side wall of the reduction section and the axis is 5-60 degrees.

[0048] Wherein, a material distributor is also arranged at the head of the dense phase fluidization section; the cooling zone is arranged at the tail of the dense phase fluidization section; and the cooling zone is provided with one or more coolant distributors.

[0049] In the first reactor having the above structure, the first catalyst moves upward to the first lifting section under the lifting effect of the pre-lifting medium, forms a catalyst piston flow with uniform density in the first lifting section, and then enters the dense phase fluidization section to react, and is cooled by the coolant introduced into the cooling zone. The post-reaction logistics can be quickly cooled and the gas-solid separation can be quickly carried out, thereby reducing the yield of by-products.

[0050] Preferably, the reacted logistics is mixed with the coolant introduced through the coolant distributor and cooled to the target temperature within a preset time; the preset time is within 2 seconds, preferably within 1 second, and more preferably within 0.5 seconds; the coolant is selected from one or more of liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel and water.

[0051] The density of the first catalyst in the dense phase fluidized bed is 300-650 kg / m 3, more preferably 500-650kg / m 3 For example, in some embodiments of the present invention, the density of the first catalyst is 100 kg / m 3 , 200kg / m 3 、300kg / m 3 、350kg / m 3 , 400kg / m 3 , 450kg / m 3 , 500kg / m 3 、550kg / m 3 、600kg / m 3 、650kg / m 3 , 700kg / m 3 When the olefin-rich raw material is reacted on the catalyst with the above distribution density, the yield of methane in the product can be significantly reduced, and the yield and selectivity of the low-carbon system can be improved.

[0052] Among them, the conditions of the first catalytic conversion reaction include: reaction temperature of 550-800°C, preferably 580-750°C, and more preferably 600-700°C; reaction pressure of 0.01-1MPa, preferably 0.1-0.8MPa, and more preferably 0.2-0.5MPa; reaction time of 0.05-10 seconds, preferably 0.1-5 seconds, and more preferably 0.2-2 seconds; the weight ratio of the first catalyst to the olefin-rich feedstock is (5-50):1, preferably (10-35):1, and more preferably (12-30):1.

[0053] Preferably, the olefin content in the olefin-rich feedstock is 50-100 wt%, preferably 80-100 wt%.

[0054] Preferably, the olefin-rich feedstock is a gas phase feed.

[0055] Preferably, the olefins in the olefin-rich feedstock are C4-C 12 Olefins, preferably C4-C6 olefins.

[0056] Wherein, the first catalyst is a mesoporous molecular sieve catalyst and / or a small-pore molecular sieve catalyst. The mesoporous molecular sieve catalyst is a zeolite with an MFI structure, a zeolite with an MFI structure containing phosphorus and / or rare earth. The small-pore molecular sieve catalyst is an excellent shape-selective molecular sieve with a three-dimensional framework structure.

[0057] Preferably, the medium-pore molecular sieve catalyst is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48; the small-pore molecular sieve catalyst is selected from one or more of SAPO-34, SAPO-11 and SAPO-47.

[0058] The method further comprises: stripping the first spent catalyst, then charring and regenerating the stripped first spent catalyst, and returning the regenerated first catalyst to the first reactor; or mixing the first spent catalyst with the regenerated first catalyst and returning the mixture to the first reactor.

[0059] The method further includes: contacting heavy hydrocarbon oil with a second catalyst in a second reactor for a second catalytic conversion reaction to obtain reaction oil gas containing light oil and a second catalyst to be regenerated; then mixing the reaction oil gas containing light oil with the first reaction oil gas, and performing a first separation on the mixed oil gas to obtain dry gas, light olefins and C5 and above fraction oils, performing a second separation on the C5 and above fraction oils and returning the separated olefin-rich components to the first reactor; stripping the second catalyst to be regenerated and regenerating the stripped second catalyst to be regenerated by charring, and then returning the regenerated second catalyst to the second reactor; and stripping the first catalyst to be regenerated and then transporting it to a regenerator for charring and regeneration.

[0060] The method further comprises: mixing the first catalyst to be regenerated taken out through the slide valve with the hot regenerated second catalyst to obtain a mixed catalyst; contacting the heavy hydrocarbon oil with the mixed catalyst in the second reactor for a second catalytic conversion reaction to obtain a reaction oil gas containing light oil and a catalyst to be regenerated; when the temperature of the reaction oil gas containing light oil and the catalyst to be regenerated in the middle and upper area of ​​the reaction zone of the second reactor exceeds 530°C, a cooling zone is set downstream of the reaction zone, and the reaction oil gas containing light oil and the catalyst to be regenerated are cooled to below 530°C; stripping the catalyst to be regenerated, and charring and regenerating the stripped catalyst to be regenerated and returning them to the first reactor and the second reactor respectively; mixing the reaction oil gas containing light oil with the first reaction oil gas, and performing a first separation on the mixed oil gas to obtain dry gas, light olefins and C5 and above distillates, performing a second separation on the C5 and above distillates and returning the separated olefin-rich components to the first reactor.

[0061] The heavy hydrocarbon oil is selected from one or more of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, heavy aromatic raffinate oil, coal liquefaction oil, oil sand oil and shale oil.

[0062] Among them, the conditions of the second catalytic conversion reaction include: reaction temperature of 500-600°C, preferably 530-580°C; reaction pressure of 0.01-1MPa, preferably 0.05-1MPa; reaction time of 0.01-100s, preferably 0.1-80s; weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-70):1.

[0063] The first reactor of an embodiment of the present invention is described in detail below. Figure 1 As shown, the first reactor is a fluidized bed reactor, and the first reactor includes a first lifting section, an expansion section, a dense phase fluidization section, a reduction section and a second lifting section from bottom to top. The diameter of the first lifting section is 0.2-5m, and its height accounts for 5-20% of the total height of the first reactor. The angle between the side wall of the expansion section and the axis is 5-60 degrees, and the height of the expansion section accounts for 1-10% of the height of the first reactor; the ratio of the diameter to the height of the dense phase fluidization section is (1-20):1, and its height accounts for 20-70% of the total height of the first reactor. The joint between the dense phase fluidization section and the second lifting section is a reduction section. The angle between the side wall of the reduction section and the axis is 5-45 degrees, and its height accounts for 5-20% of the total height of the first reactor. The ratio of the diameter of the second lifting section to the diameter of the reaction zone is (0.2-0.8):1, and the height of the second lifting section accounts for 0-20% of the total height of the first reactor.

[0064] exist Figure 1 In the first reactor shown, the pre-lifting medium enters the first lifting section 33 from the bottom of the first reactor A through pipeline 1, and the first catalyst from pipeline 24 enters the reaction zone of the first reactor A under the lifting effect of the pre-lifting medium and moves upward to accelerate. The olefin-rich raw material is injected into the bottom of the reaction zone through pipeline 2, and after being distributed by the material distributor 3, it contacts with the first catalyst preheated to above 650°C to undergo catalytic cracking reaction. The coolant is introduced into the coolant distributor 35 provided in the cooling zone through pipeline 4, and the product after the reaction is directly contacted with the coolant for instantaneous cooling, and the temperature is reduced to below 530°C within 2 seconds, and gas-solid rapid separation is performed to obtain the first reaction oil gas and the first catalyst to be regenerated, and the first reaction oil gas leaves the first reactor A through the second lifting section. The first catalyst to be regenerated is moved out of the first reactor A from pipeline 8 through the control of the slide valve 7.

[0065] Figure 2 is a first reactor according to another embodiment of the present invention, wherein the first reactor is Figure 1The difference of the first reactor shown is that the feed position is different. The pre-lifting medium enters the first lifting section 33 from the bottom of the first reactor A through pipeline 1, and the first catalyst from pipeline 24 ascends to the reaction zone under the lifting effect of the pre-lifting medium. The olefin-rich raw material enters the reaction zone from the side of the first reactor through pipeline 36, and after being distributed by the material distributor 3, it contacts with the first catalyst preheated to above 650°C to undergo catalytic cracking reaction. The coolant is introduced into the coolant distributor 35 provided in the cooling zone through pipeline 4, and the product after the reaction contacts the coolant and is cooled to below 530°C within 2 seconds, and then the gas-solid is quickly separated to obtain the first reaction oil gas and the first catalyst to be regenerated, and the first reaction oil gas leaves the first reactor through the second lifting section. The first catalyst to be regenerated is moved out of the first reactor from pipeline 8 through the control of the slide valve 7.

[0066] In a specific embodiment of the present invention, the method provided by the present invention can be carried out according to Figure 3 The process shown in the figure is completed, the pre-lifting medium enters from the bottom of the first reactor 2 through pipeline 1, and the first catalyst from pipeline 24 accelerates upward along the first lifting section of the first reactor under the lifting effect of the pre-lifting medium. The olefin-rich raw material is injected into the bottom of the reaction zone through pipeline 2, and after being distributed by the material distributor 3, it contacts with the preheated first catalyst to undergo catalytic cracking reaction. The coolant is introduced into the distributor 35 provided in the cooling zone through pipeline 4, and the product after reaction contacts with the coolant and cools down to below 530°C within 2 seconds, and then leaves the first reactor through the second lifting section. The reacted catalyst is controlled by the slide valve 7 and passes through pipeline 8 from the bottom of the reaction zone, after gas-solid separation, it is introduced into the stripping section 9, and contacts with the stripping steam from pipeline 25 to strip the remaining reaction oil gas on the catalyst. The reaction oil gas stripped from the first catalyst to be produced is separated by the cyclone separator 13 and enters the gas collecting chamber 14.

[0067] The first catalyst to be regenerated after stripping enters the regenerator 16 through the regenerator inclined pipe 15, and is contacted with the oxygen-containing gas introduced into the regenerator through the pipeline 17 to be burned and regenerated, so as to remove the coke on the catalyst to be regenerated, so as to regenerate the deactivated first catalyst to be regenerated. Supplementary fuel enters the regenerator through the pipeline 18 to supplement heat for the regenerated first catalyst.

[0068] The reaction oil and gas leaving the second lifting section of the first reactor enters the distillation tower 21 through the large oil and gas pipeline 20 for the first separation, the separated hydrogen, methane and ethane are led out through the pipeline 22, ethylene is led out through the pipeline 23, propylene is led out through the pipeline 26, butene is led out through the pipeline 27, butene may be returned to the first reactor as a raw material for further reaction, propane and butane are led out through the pipeline 28; the first catalytic cracking distillate oil with an initial boiling point of any temperature greater than 20°C and less than 140°C is introduced into the olefin separation device 30 through the pipeline 29 for the second separation treatment, and a stream containing no olefins and a stream rich in olefins are separated to obtain a stream containing no olefins and a stream rich in olefins. The stream containing no olefins is led out through the pipeline 31, and the stream rich in olefins is returned to the first reactor as a raw material for further reaction through the pipeline 32.

[0069] In another specific embodiment of the present invention, Figure 4 As shown, it is Figure 3 The difference between the processes shown is that the destination of the catalyst after the reaction in the first reactor is different. In this specific embodiment, the catalytic cracking catalyst after the reaction in the first reactor is controlled by a slide valve 7, enters the bottom of the first reactor A through a pipeline 8, is mixed with the regenerated first catalyst from the pipeline 24, and is then sent to the reaction zone of the first reactor.

[0070] In another specific embodiment of the present invention, Figure 5 As shown, the first reactor A is coupled to the second reactor B. The pre-lifting medium enters the first lifting section 33 from the bottom of the first reactor A through pipeline 1, and the first catalyst from pipeline 24 ascends to the reaction zone under the lifting effect of the pre-lifting medium. The olefin-rich raw material is injected into the bottom of the reaction zone of the first reactor A through pipeline 2, and after being distributed by the material distributor 3, the filling density is greater than 100 kg / m 3 The reaction takes place on the hot catalytic conversion catalyst. The coolant is introduced into the distributor 35 of the cooling zone 34 of the first reactor A through the pipeline 4. The reacted logistics directly contacts with the coolant for instantaneous cooling and rapid gas-solid separation, thereby obtaining the first reaction oil gas and the first catalyst to be generated.

[0071] The heavy feedstock oil is injected into the bottom of the second reactor B through pipeline 5 together with the atomized steam from pipeline 6. The heavy feedstock oil contacts and reacts with the second catalyst introduced from pipeline 19 to obtain reaction oil gas containing light oil and the second catalyst to be regenerated. The reaction oil gas and the second catalyst to be regenerated are cooled in the cooling zone, wherein the cooling medium is injected into the cooling zone through pipeline 38. The first catalyst to be regenerated in the first reactor A is controlled by a slide valve 7 and is introduced into the stripping section 9 after gas-solid separation from the bottom of the reaction zone of the first reactor A through pipeline 8, and contacts with the stripping steam from pipeline 25. The oil gas stripped from the catalyst to be regenerated passes through a cyclone separator 13 and enters a gas collecting chamber 14. The stripped catalyst to be regenerated enters a regenerator 16 through a regenerated inclined pipe 15, and the main air enters the regenerator 16 through pipeline 17 to remove coke on the catalyst to be regenerated, so as to regenerate the deactivated catalyst to be regenerated. Supplementary fuel enters the regenerator through pipeline 18 to supplement heat for the regenerated catalyst. The preheated regenerated catalyst enters the second reactor B via pipeline 19 and enters the first reactor A via pipeline 24.

[0072] The first reaction oil gas and the reaction oil gas containing light oil enter the distillation tower 21 through the large oil and gas pipeline 20 for the first separation treatment, the separated hydrogen, methane and ethane are led out through pipeline 22, ethylene is led out through pipeline 23, propylene is led out through pipeline 26, butene is led out through pipeline 27, butene can be returned to the first reactor A for further reaction or not, propane and butane are led out through pipeline 28; the first catalytic cracking distillate oil with an initial distillation point of any temperature greater than 20°C and less than 140°C is introduced into the olefin separation device 30 through pipeline 29 for the second separation treatment, and a logistics containing no olefins and a logistics rich in olefins are separated: the logistics containing no olefins is led out through pipeline 31, and the logistics rich in olefins is returned to the first reactor A through pipeline 32 as a raw material for further reaction.

[0073] A sixth embodiment of the present invention is as follows Figure 1 and Figure 6 As shown, it is Figure 5 The difference between the illustrated embodiments is that the destination of the first catalyst to be regenerated in the first reactor A is different. The first catalyst to be regenerated is controlled by a slide valve 7 and enters the first lifting section of the second reactor B from the bottom of the first reactor A through a pipeline 37, where it is mixed with the regenerated catalyst from the pipeline 19 and is contacted with the heavy crude oil from the pipeline 5 to react.

[0074] The present invention is further described in detail by way of examples below, but the present invention is not limited thereby. The raw materials used in the examples can be obtained through commercial sources. Among them, the commercial brand of the catalyst used in the examples and comparative examples is TCC-1, which is produced by Qilu Branch of Sinopec Catalyst Co., Ltd.

[0075] The heavy hydrocarbon oil used in the examples and comparative examples of the present invention is heavy oil I, and the properties of heavy oil I are shown in Table 1.

[0076] Table 1

[0077]

[0078]

[0079] Example 1

[0080] The experiment of this example was Figure 3 The first reactor is a medium-sized fluidized bed reactor, the raw material is 1-pentene, and the catalyst is TCC-1.

[0081] The preheated raw material 1-pentene enters the bottom of the reaction zone of the first reactor and enters the reaction zone through the gas-solid mixed fluid distributor, and contacts with the first catalyst preheated to 650°C for catalytic cracking reaction. The catalyst density is 400kg / m 3 The oil and gas after the reaction are rapidly cooled to below 530°C in the cooling zone and separated in a cyclone separator to obtain the catalyst to be produced and the oil and gas rich in ethylene and propylene. The oil and gas rich in ethylene and propylene are sent to the subsequent separation device for separation. The reaction conditions and product distribution are shown in Table 2.

[0082] Comparative Example 1

[0083] The test of this comparative example was Figure 1 The process was carried out on a medium-sized fluidized bed reactor. The raw material was 1-pentene and the catalyst was TCC-1. The difference between this and Example 1 was that the density of the first catalyst in the dense phase fluidized bed of the first reactor was 90 kg / m 3 The reaction conditions and product distribution are shown in Table 2.

[0084] Table 2

[0085]

[0086]

[0087] As can be seen from Table 2, the method of the present invention has a higher yield of ethylene and propylene when high-temperature cracking is carried out in a fluidized bed reactor. The content of ethylene, propylene and butene in the obtained reaction oil gas is as high as 63.62%, and the value of ethylene / propylene is as high as 0.76.

[0088] Example 2

[0089] The experiment of this example was Figure 5 The process is carried out according to the shown process, and the first reactor is a medium-sized fluidized bed reactor.

[0090] Hot ingredients 1 Pentene enters the bottom of the reaction zone of the first reactor and contacts with the TCC-1 catalyst preheated to 650°C for the first catalytic conversion reaction. The catalyst density is 400 kg / m 3 ; The reacted logistics is contacted with a cooling medium to reduce the temperature, thereby obtaining a first reaction oil gas; the reacted catalyst is introduced into a stripping section from the bottom of the reaction zone of the first reactor through a slide valve control after gas-solid separation, thereby obtaining a first catalyst to be generated;

[0091] The heavy oil I is introduced into the second reactor from the bottom of the second reactor to contact with the regenerated TCC-1 catalyst to undergo a second catalytic conversion reaction, thereby obtaining a reaction oil gas containing light oil and a second catalyst to be regenerated;

[0092] The first catalyst to be regenerated and the second catalyst to be regenerated enter the regenerator for charring and regeneration to obtain a regenerated catalyst;

[0093] The first reaction oil gas and the reaction oil gas containing light oil are mixed and sent to the fractionation device for cutting according to the distillation range to obtain ethylene, propylene, butene and olefin-containing logistics; the olefin-containing logistics is introduced into the olefin separation device for separation to obtain olefin-rich logistics (the olefin content in the olefin-rich logistics is 80 weight%), and then the olefin-rich logistics is returned to the reactor from the bottom of the reaction zone of the reactor. The reaction conditions and product distribution are shown in Table 3.

[0094] Comparative Example 2

[0095] The test of this comparative example was carried out with reference to Example 2. The difference between this comparative example and Example 2 is that the catalyst density in the dense phase fluidized bed of the first reactor is 90 kg / m 3 The reaction conditions and product distribution are shown in Table 3.

[0096] Table 3

[0097]

[0098]

[0099] As can be seen from Table 3, by coupling the production of low-carbon olefins from light raw materials with the catalytic cracking of heavy oil, and by adjusting the density of the catalyst and the type of reactor in the catalytic cracking reactor of the light raw material, the yields of ethylene, propylene and butene in the resulting reaction oil and gas have been greatly improved.

[0100] 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, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0101] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0102] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A catalytic conversion method for producing light olefins, characterized in that: The method comprises the following steps: The olefin-rich raw material is brought into contact with the hot regenerated first catalyst in the dense phase fluidized bed of the first reactor to carry out a first catalytic conversion reaction, and the post-reaction flow is instantaneously cooled in a cooling zone downstream of the dense phase fluidized bed to cool the post-reaction flow to a target temperature of 450-530° C. and is separated and then sent out of the first reactor to obtain a first reaction oil gas and a first catalyst to be regenerated; A portion of the first catalyst in the dense phase fluidized bed is taken out from the slide valve at the bottom of the first reactor so that the density of the first catalyst in the dense phase fluidized bed is 100-700 kg / m 3 .

2. The catalytic conversion method according to claim 1, wherein: The first reactor comprises, from bottom to top, a first lifting section, an expansion section, a dense phase fluidization section, a reduction section, and a second lifting section; the angle between the side wall of the expansion section and the axis is 5-60 degrees; the ratio of the diameter to the height of the dense phase fluidization section is (1-20):1; the angle between the side wall of the reduction section and the axis is 5-60 degrees; The head of the dense phase fluidization section is also provided with a material distributor; The cooling zone is arranged at the tail of the dense phase fluidization section; The cooling zone is provided with one or more coolant distributors, the product after the reaction is mixed with the coolant introduced through the coolant distributor, and is cooled to the target temperature within a preset time; The preset time is within 2 seconds, preferably within 1 second, and more preferably within 0.5 seconds; The coolant is selected from one or more of liquefied gas, crude gasoline, stabilized gasoline, diesel, heavy diesel and water.

3. The catalytic conversion method according to claim 1, wherein: The density of the first catalyst in the dense phase fluidized bed is 300-650 kg / m 3 , preferably 500-650kg / m 3 .

4. The catalytic conversion method according to claim 1, wherein: The conditions of the first catalytic conversion reaction include: a reaction temperature of 550-800°C, preferably 580-750°C, and more preferably 600-700°C; The reaction pressure is 0.01-1MPa, preferably 0.1-0.8MPa, and more preferably 0.2-0.5MPa; The reaction time is 0.05-10 seconds, preferably 0.1-5 seconds, and more preferably 0.2-2 seconds; The weight ratio of the first catalyst to the olefin-rich feedstock is (5-50):1, preferably (10-35):1, and more preferably (12-30):

1.

5. The catalytic conversion method according to claim 1, wherein: The olefin content in the olefin-rich feedstock is 50-100 wt %, preferably 80-100 wt %; The olefin-rich raw material is a gas phase feed; The olefins in the olefin-rich feedstock are C4-C 12 Olefins, preferably C4-C6 olefins.

6. The catalytic conversion method according to claim 1, wherein: The first catalyst is a medium pore molecular sieve catalyst and / or a small pore molecular sieve catalyst; The mesoporous molecular sieve catalyst is selected from one or more of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38 and ZSM-48; The small pore molecular sieve catalyst is selected from one or more of SAPO-34, SAPO-11 and SAPO-47.

7. The catalytic conversion method according to claim 1, wherein: The method further comprises: Stripping the first spent catalyst, then charring and regenerating the stripped first spent catalyst, and returning the regenerated first catalyst to the first reactor; or The first spent catalyst is mixed with the regenerated first catalyst and then returned to the first reactor.

8. The catalytic conversion method according to claim 1, wherein: The method further comprises: The heavy hydrocarbon oil is brought into contact with the second catalyst in the second reactor to perform a second catalytic conversion reaction to obtain a reaction oil gas containing light oil and a second catalyst to be produced; Then, the reaction oil gas containing light oil is mixed with the first reaction oil gas, and the mixed oil gas is subjected to a first separation to obtain dry gas, light olefins and C5 and above distillate oil, and the C5 and above distillate oil is subjected to a second separation and the separated olefin-rich component is returned to the first reactor; The second spent catalyst is stripped and the stripped second spent catalyst is regenerated by burning, and then the regenerated second catalyst is returned to the second reactor; and the first spent catalyst is stripped and then transported to the regenerator for regeneration by burning.

9. The catalytic conversion method according to claim 1, wherein: The method further comprises: mixing the first catalyst to be regenerated taken out through the slide valve with the hot regenerated second catalyst to obtain a mixed catalyst; The heavy hydrocarbon oil is brought into contact with the mixed catalyst in a second reactor to perform a second catalytic conversion reaction, thereby obtaining a reaction oil gas containing light oil and a catalyst to be regenerated; wherein, when the temperature of the reaction oil gas containing light oil and the catalyst to be regenerated in the upper region of the reaction zone of the second reactor exceeds 530° C., a cooling zone is provided downstream of the reaction zone, and the reaction oil gas containing light oil and the catalyst to be regenerated are cooled to below 530° C.; Stripping the spent catalyst, burning and regenerating the stripped spent catalyst, and returning the stripped spent catalyst to the first reactor and the second reactor respectively; The reaction oil gas containing light oil is mixed with the first reaction oil gas, and the mixed oil gas is subjected to a first separation to obtain dry gas, light olefins and C5 and above distillate oils, and the C5 and above distillate oils are subjected to a second separation and the separated olefin-rich components are returned to the first reactor.

10. The catalytic conversion method according to claim 8 or 9, wherein: The heavy hydrocarbon oil is selected from one or more of vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, heavy aromatic raffinate oil, coal liquefaction oil, oil sand oil and shale oil; The conditions of the second catalytic conversion reaction include: reaction temperature of 500-600°C, preferably 530-580°C; reaction pressure of 0.01-1MPa, preferably 0.05-1MPa; reaction time of 0.01-100s, preferably 0.1-80s; The weight ratio of the second catalyst to the heavy hydrocarbon oil is (1-100):1, preferably (3-70):1.

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