Catalytic conversion method and system for producing ethylene and propylene

Abstract

The invention relates to a catalytic conversion method and system for producing ethylene and propylene, and the method comprises the following steps: feeding an olefin-rich raw material into a dense-phase bed section of an olefin catalytic conversion reactor to contact with a first catalyst to carry out a first catalytic conversion reaction, and instantaneously cooling the reacted material flow to a target temperature of 450-530 DEG C in a dilute-phase section of the reactor, carrying out gas-solid separation on the cooled material flow at the outlet of the reactor; extracting part of the first catalyst from the dense-phase bed section of the olefin catalytic conversion reactor as a second catalyst, feeding the second catalyst into a heavy oil catalytic conversion reactor, and introducing heavy oil into the heavy oil catalytic conversion reactor to be in contact with the second catalyst for a second catalytic conversion reaction, returning a C5 < + >-containing olefin material flow separated from a reaction product to the olefin catalytic conversion reactor for continuous reaction; the method provided by the invention is beneficial to promoting the catalytic conversion of heavy oil to generate ethylene and propylene, and obviously improves the yield and selectivity of ethylene.

Description

Technical Field

[0001] This invention belongs to the field of petrochemicals, specifically relating to a catalytic conversion method and system for producing ethylene and propylene. Background Technology

[0002] Ethylene and propylene are important organic chemical raw materials. Ethylene can be used to prepare products such as polyethylene, ethylene oxide, ethylene glycol, polyvinyl chloride, styrene, and vinyl acetate, while propylene is mainly used to prepare chemical products such as acrylonitrile, propylene oxide, and acetone.

[0003] Steam cracking is currently the main method for propylene production. This method uses light hydrocarbons and naphtha as feedstocks, mixing them with steam under high temperature and pressure to produce low-carbon olefins such as ethylene and propylene. However, steam cracking is energy-intensive and requires a large amount of light hydrocarbons, making it susceptible to shortages of light resources. On the other hand, a large amount of high-carbon olefins produced as a byproduct of refineries cannot be effectively utilized. Utilizing the catalytic conversion of high-carbon olefins to produce high-value ethylene and propylene would enable more efficient resource utilization.

[0004] CN101092323A discloses a method for catalytic cracking using a mixture of C4-C8 olefins as raw materials. By recycling the C4 fraction in the reaction products back to the catalytic cracking, the conversion rate of olefins and the yield of ethylene and propylene in the products are improved. However, the products obtained by this method contain a large amount of butene and there are problems such as high energy consumption for C4 separation.

[0005] CN115873623A discloses a method for producing low-carbon olefins and aromatics by combining a riser and a dense-phase fluidized bed reactor. In this method, heavy feedstocks are subjected to non-hydrogen-dependent catalytic cracking in a riser reactor, and either heavy or light feedstocks are subjected to catalytic cracking in a dense-phase fluidized bed reactor. However, the yield of low-carbon olefins (ethylene + propylene + butene) in the resulting products is less than 20% by weight.

[0006] CN114763485A discloses a method for using olefins and heavy oil as raw materials and catalytically converting the two raw materials separately, and recycling the butene and C5 or higher olefin streams in the product back to the reactor for reprocessing.

[0007] However, in existing methods for producing ethylene and propylene from olefin-containing feedstocks, the yields of ethylene and propylene still need to be further improved. Summary of the Invention

[0008] The purpose of this invention is to further improve the yield of ethylene and propylene in the catalytic conversion products of olefin-containing feedstocks.

[0009] To achieve the above objectives, a first aspect of the present invention provides a catalytic conversion method for producing ethylene and propylene, the method comprising: The olefin-rich feedstock is fed into the dense-phase bed section of the olefin catalytic conversion reactor to contact the first catalyst for the first catalytic conversion reaction. The reaction stream is then instantaneously cooled to a target temperature of 450-530 °C in the dilute-phase section of the reactor. The cooled stream is then subjected to gas-solid separation at the reactor outlet to obtain the first reaction oil and gas and the first catalyst to be generated. The temperature of the first catalyst before the reaction is higher than or equal to 650 °C. A portion of the first catalyst is extracted from the dense-phase bed section of the olefin catalytic conversion reactor and fed into the heavy oil catalytic conversion reactor as the second catalyst. Heavy oil is introduced into the heavy oil catalytic conversion reactor to contact the second catalyst for the second catalytic conversion reaction. The reaction stream is then separated to obtain the second reaction oil and gas and the second catalyst to be generated. The first and second reaction oil gases are separated to obtain ethylene, propylene, liquefied petroleum gas, butene, and C-containing compounds. 5+ Olefin stream, and make the C-containing 5+ The olefin stream is returned to the olefin catalytic conversion reactor to continue the reaction.

[0010] Optionally, the time for the post-reaction stream to cool down to the target temperature is 0.1-2 seconds, preferably 0.5-1 seconds; optionally, the instantaneous cooling method includes: bringing the post-reaction stream into contact with a cooling medium injected into the dilute phase section of the reactor for cooling; the cooling medium is selected from one or more of liquefied petroleum gas, crude gasoline, coking gasoline and stabilized gasoline.

[0011] Optionally, the density of the first catalyst in the dense phase bed section is 300-750 kg / m³. 3 The preferred value is 350-500 kg / m³. 3The first catalyst extracted from the dense-phase bed section of the olefin catalytic conversion reactor accounts for 5-40% by weight of the catalyst circulation in the olefin catalytic conversion reactor, preferably 5-20% by weight. Optionally, the first catalytic conversion reaction conditions include: a reaction temperature of 550-800 °C in the dense-phase bed section, preferably 600-700 °C; a reaction pressure of 0.02-1 MPa, preferably 0.1-0.8 MPa; a residence time of the olefin-rich feedstock in the dense-phase bed section of 0.01-10 seconds, preferably 0.1-3 seconds; and a weight ratio of the first catalyst to the olefin-rich feedstock of (1-200):1, preferably (5-50):1, more preferably (10-30):1. Optionally, the second catalytic conversion reaction conditions include: a reaction temperature of 400-650 °C, preferably 450-600 °C, more preferably 520-580 °C; and a reaction pressure of 0.05-1 MPa, preferably 0.1-0.8 MPa. MPa; reaction time is 0.01-100 seconds, preferably 0.1-80 seconds, more preferably 0.2-70 seconds; the weight ratio of catalyst to heavy oil is (1-100):1, preferably (3-70):1, more preferably (4-30):1.

[0012] Optionally, the weight ratio of the olefin-rich feedstock to the heavy oil is 1:(1-50), preferably 1:(1-20), more preferably 1:(2-10); the olefin content in the olefin-rich feedstock is 60-100% by weight, preferably 90-100% by weight, more preferably pure olefin feedstock; the olefins in the olefin-rich feedstock are selected from C5-C7 olefins; optionally, the olefin-rich feedstock comes from the C5 and above fraction produced by an alkane dehydrogenation unit or a catalytic cracking unit in an oil refinery. The heavy oil is selected from at least one of the following: C5 or higher fractions produced, C5 or higher fractions produced by the steam cracking unit of an ethylene plant, C5 or higher olefin-rich fractions produced as a byproduct of MTO, and C5 or higher olefin-rich fractions produced as a byproduct of MTP; optionally, the heavy oil is selected from petroleum hydrocarbons and / or mineral oils; the petroleum hydrocarbons are selected from one or more of vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, and heavy aromatics raffinate; the mineral oils are selected from one or more of coal liquefaction oil, oil sands oil, and shale oil.

[0013] Optionally, based on the total weight of the first catalyst, the first catalyst comprises 1-50% by weight of molecular sieve, 5-99% by weight of inorganic oxide, and 0-70% by weight of clay; optionally, the molecular sieve comprises mesoporous molecular sieve and / or microporous molecular sieve; the mesoporous molecular sieve is selected from at least one of ZSM-5 series zeolite and ZRP zeolite; the microporous molecular sieve is selected from SAPO series zeolite; the inorganic oxide is selected from one or more of silica and alumina; the clay is selected from one or more of kaolin, hydrous kaolin, montmorillonite, diatomaceous earth, soapstone, retardant, sepiolite, attapulgite, hydrotalcite, and bentonite.

[0014] Optionally, the olefin catalytic conversion reactor is selected from one of a bubbling fluidized bed reactor and a turbulent fluidized bed reactor, or a combination of two reactors in series, preferably a turbulent fluidized bed reactor; the heavy oil catalytic conversion reactor is selected from one of a riser, a constant linear velocity fluidized bed, a constant diameter fluidized bed, an upward conveying line, and a downward conveying line, or a combination of two reactors in series; wherein, the riser is a constant diameter riser reactor or a variable diameter fluidized bed reactor.

[0015] Optionally, the method further includes: stripping the first spent catalyst and / or the second spent catalyst and then sending it to a regenerator for coking regeneration to obtain a regenerated catalyst; introducing part or all of the regenerated catalyst into the olefin catalytic conversion reactor; preferably, sending part of the regenerated catalyst into the heavy oil catalytic conversion reactor to participate in the reaction.

[0016] Optionally, the dense-phase bed section of the olefin catalytic conversion reactor is provided with a catalyst outlet, and the distance between the catalyst outlet and the bottom of the dense-phase bed section is 1 / 10-1 / 2, preferably 1 / 10-1 / 4, of the height of the dense-phase bed section; Optionally, the distance between the catalyst inlet of the olefin catalytic conversion reactor and the top of the dense-phase bed section is 1 / 10-1 / 2, preferably 1 / 10-1 / 4, of the height of the dense-phase bed section.

[0017] A second aspect of the present invention provides a reaction system for producing ethylene and propylene, the system comprising: an olefin catalytic conversion reactor, a heavy oil catalytic conversion reactor, and a regenerator; the olefin catalytic conversion reactor comprises, from bottom to top, a first riser section, a dense-phase fluidization section, and a dilute-phase section; the dense-phase fluidization section of the olefin catalytic conversion reactor is provided with a regenerated catalyst inlet and a catalyst outlet located below the regenerated catalyst inlet, and the dilute-phase section is provided with a cooling medium distributor; the heavy oil catalytic conversion reactor comprises, from bottom to top, a third riser section, a reaction section, and a fourth riser section; the bottom of the third riser section of the heavy oil catalytic conversion reactor is provided with a catalyst outlet; the bottom of the regenerator is provided with an oxygen-containing gas inlet and a catalyst inlet to be recycled, and the lower part is provided with a first regenerated catalyst outlet; the regenerated catalyst inlet of the olefin catalytic conversion reactor 1 is connected to the first regenerated catalyst outlet of the regenerator, and the catalyst outlet is connected to the catalyst outlet of the heavy oil catalytic conversion reactor.

[0018] Optionally, the system further includes a first settling tank connected to the outlet of the olefin catalytic conversion reactor and a second settling tank connected to the outlet of the heavy oil catalytic conversion reactor; the bottom of the first settling tank is provided with a first stripping section, and the bottom of the first stripping section is provided with a first regenerated catalyst outlet; the bottom of the second settling tank is provided with a second stripping section, and the bottom of the second stripping section is provided with a second regenerated catalyst outlet; the regenerated catalyst inlet of the regenerator is connected to the first regenerated catalyst outlet of the first stripping section and the second regenerated catalyst outlet of the second stripping section, respectively; preferably, the outlet of the dilute phase section of the olefin catalytic conversion reactor is further provided with a second lift section; the outlet of the second lift section is connected to a rapid separation device; preferably, the lower part of the regenerator is further provided with a second regenerated catalyst outlet, the lower part of the third lift section of the heavy oil catalytic conversion reactor is provided with a regenerated catalyst inlet, and the regenerated catalyst inlet of the heavy oil catalytic conversion reactor is connected to the second regenerated catalyst outlet of the regenerator.

[0019] Through the above technical solution, this invention contacts olefin-rich feedstock with a high-temperature first catalyst, then instantly cools the reaction stream and rapidly separates the reaction stream at the outlet of the olefin catalytic conversion reactor. This effectively controls the depth of the olefin-rich feedstock catalytic conversion reaction, thereby increasing the yield of ethylene and propylene. Simultaneously, a portion of the first catalyst is collected from the dense-phase bed section of the olefin catalytic conversion reactor and fed into the second heavy oil catalytic conversion reactor. The collected first catalyst has a lower temperature, and the coke deposits on the collected catalyst have a modifying effect on the catalyst, which is beneficial to promoting the catalytic conversion of heavy oil to ethylene and propylene, significantly improving the yield and selectivity of ethylene.

[0020] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating a specific implementation of the method provided by the present invention.

[0022] Figure 2 This is a flowchart illustrating another specific embodiment of the method provided by the present invention.

[0023] Figure 3 This is a flowchart illustrating another specific embodiment of the method provided by the present invention.

[0024] Explanation of reference numerals in the attached figures: Detailed Implementation

[0025] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0026] All pressures involved in this invention are gauge pressures.

[0027] A first aspect of the present invention provides a catalytic conversion method for producing ethylene and propylene, the method comprising: feeding an olefin-rich feedstock into a dense-phase bed section of an olefin catalytic conversion reactor to contact a first catalyst for a first catalytic conversion reaction; instantaneously cooling the reaction stream to a target temperature of 450-530 °C in a dilute-phase section of the reactor; and performing gas-solid separation on the cooled stream at the reactor outlet to obtain a first reaction oil and gas and a first catalyst to be generated; wherein the temperature of the first catalyst before the reaction is higher than or equal to 650 °C; A portion of the first catalyst is extracted from the dense-phase bed section of the olefin catalytic conversion reactor and fed into the heavy oil catalytic conversion reactor as the second catalyst. Heavy oil is introduced into the heavy oil catalytic conversion reactor to contact the second catalyst for the second catalytic conversion reaction. The reaction stream is then separated to obtain the second reaction oil and gas and the second catalyst to be generated. The first and second reaction oil gases are separated to obtain ethylene, propylene, liquefied petroleum gas, butene, and C-containing compounds. 5+ Olefin stream, and make the C-containing 5+ The olefin stream is returned to the olefin catalytic conversion reactor to continue the reaction.

[0028] The technical solution of this invention involves contacting olefin-rich feedstock with a high-temperature first catalyst, then instantly cooling the reaction stream and rapidly separating the reaction stream at the outlet of the olefin catalytic conversion reactor. This effectively controls the depth of the catalytic conversion reaction of the olefin-rich feedstock, thereby increasing the yield of ethylene and propylene. Simultaneously, a portion of the first catalyst is collected from the dense-phase bed section of the olefin catalytic conversion reactor and fed into a second heavy oil catalytic conversion reactor. The collected first catalyst has a lower temperature, and the coke deposits on the collected catalyst have a modifying effect on the catalyst, which is beneficial for promoting the catalytic conversion of heavy oil to ethylene and propylene, significantly improving the yield and selectivity of ethylene.

[0029] In this invention, the C-containing 5+ The olefin stream includes C5 olefins and olefins of higher C5 content, preferably a stream rich in C5-C7 olefins. This invention utilizes C-containing olefins separated from reacted oil and gas. 5+ The return of olefins to the olefin catalytic conversion reactor for further reaction is beneficial to further improve the yield of ethylene and propylene, and also further expands the range of feedstocks for the production of ethylene and propylene.

[0030] The olefins in the olefin-rich raw material are selected from C5-C7 olefins; the olefin content in the olefin-rich raw material is 60-100% by weight, preferably 90-100% by weight. More preferably, the olefin-rich raw material is a pure olefin raw material to further improve the yield of low-carbon olefins in the product, for example, it can be one or more of pentene, hexene and heptene.

[0031] The olefin-rich feedstock is derived from at least one of the following: C5 or higher fractions from an alkane dehydrogenation unit, C5 or higher fractions from a refinery catalytic cracking unit, C5 or higher fractions from an ethylene plant steam cracking unit, olefin-rich fractions with C5 or higher as byproducts of MTO, and olefin-rich fractions with C5 or higher as byproducts of MTP. The olefin-rich feedstock can also be a stream containing C5 or higher olefins produced by the method provided in this invention.

[0032] The olefin-rich feedstock is a gas-phase feed. For example, in one specific embodiment of the present invention, the olefin-rich feedstock is preheated and then enters the reaction zone in a gaseous state for catalytic conversion.

[0033] In some embodiments of the present invention, the time for the post-reaction stream to cool to the target temperature is 0.1-2 seconds, for example, it can be 0.1 seconds, 0.5 seconds, 0.8 seconds, 1.0 seconds, 1.2 seconds, 1.3 seconds, 1.4 seconds, 1.5 seconds, 1.6 seconds, 1.7 seconds, 1.8 seconds, 1.9 seconds, 2.0 seconds, or any time within the aforementioned range. By instantaneously cooling the post-reaction stream of the olefin feedstock, the control of the catalytic cracking reaction is optimized. To further improve the yield and selectivity of low-carbon olefins, the time for the post-reaction stream to cool to the target temperature is preferably 0.5-1 seconds.

[0034] Optionally, the instantaneous cooling method includes: bringing the post-reaction stream into contact with a cooling medium injected into the dilute phase section of the reactor for cooling; for example, the post-reaction stream can be instantly cooled by setting a cooling medium distributor in the dilute phase section, wherein the cooling medium is selected from one or more of liquefied petroleum gas, crude gasoline, coking gasoline and stabilized gasoline.

[0035] Specifically, the temperature of the reaction stream can be measured at the reactor outlet. The inventors discovered that after injecting a cooling medium into the dilute phase section of the reactor, the cooling medium is preferably sprayed through a nozzle and dispersed into droplets, increasing the contact area between the cooling medium and the reaction stream. Furthermore, due to the high temperature of the reaction stream, the cooling medium rapidly vaporizes, carrying away a large amount of heat, thus achieving instantaneous cooling of the stream.

[0036] The olefin catalytic conversion reactor is selected from one of a bubbling fluidized bed reactor and a turbulent fluidized bed reactor, or a combination of two reactors in series, preferably a turbulent fluidized bed reactor.

[0037] In some embodiments of the present invention, the density of the first catalyst in the dense phase bed section is 300-750 kg / m³. 3 Since the olefins in the olefin-rich feedstock are selected from C5-C7 olefins, contact between the olefin-rich feedstock and a high-density catalyst at a temperature above 650°C is beneficial for improving the catalytic cracking performance of C5-C7 olefins. To further improve the yield of low-carbon olefins in the product, the density of the first catalyst in the dense-phase bed section is preferably 350-500 kg / m³. 3 .

[0038] In some embodiments of the present invention, the first catalytic conversion reaction conditions include: a reaction temperature of 550-800 °C, preferably 600-700 °C, in the dense-phase bed section; a reaction pressure of 0.02-1 MPa, preferably 0.1-0.8 MPa; a residence time of the olefin-rich feedstock in the dense-phase bed section of 0.01-10 seconds, preferably 0.1-3 seconds; and a weight ratio of the first catalyst to the olefin-rich feedstock of (1-200):1, preferably (5-50):1, more preferably (10-30):1. Under the above reaction conditions, the olefin-rich feedstock exhibits a higher yield of low-carbon olefins during catalytic cracking. It should be noted that, unless otherwise specified, all pressures referred to in the present invention are gauge pressures.

[0039] In some embodiments of the present invention, the dense phase bed section of the olefin catalytic conversion reactor is provided with a catalyst outlet, the position of which is not higher than the catalyst feed surface. Specifically, the distance between the catalyst outlet and the bottom of the dense phase bed section is 1 / 10-1 / 2 of the height of the dense phase bed section, preferably 1 / 10-1 / 4.

[0040] In some embodiments of the present invention, the distance between the catalyst inlet of the olefin catalytic conversion reactor and the top of the dense phase bed section is 1 / 10 to 1 / 2, preferably 1 / 10 to 1 / 4, of the height of the dense phase bed section. Preferably, the catalyst inlet of the olefin catalytic conversion reactor is higher than the catalyst outlet.

[0041] In this invention, the catalytic cracking process of olefin-rich feedstock and the catalytic cracking process of heavy oil are coupled, which can be used to produce a variety of target products. This can give full play to the advantages of different feedstocks in the production of low-carbon olefins, improve the yield and selectivity of low-carbon olefins, and improve the utilization rate of petroleum resources.

[0042] In some embodiments of the present invention, the weight ratio of the olefin-rich raw material to the heavy oil is 1:(1-50), preferably 1:(1-20), and more preferably 1:(2-10).

[0043] By controlling the amount of the first catalyst extracted from the dense-phase bed section, it is also beneficial to instantly cool the post-reaction stream. Specifically, the first catalyst extracted from the dense-phase bed section of the olefin catalytic conversion reactor accounts for 5-40% by weight of the catalyst circulation amount in the olefin catalytic conversion reactor, preferably 5-20% by weight. Here, the catalyst circulation amount in the olefin catalytic conversion reactor refers to the weight of the first catalyst fed into the dense-phase bed section.

[0044] In some embodiments of the present invention, the heavy oil is selected from petroleum hydrocarbons and / or mineral oils; the petroleum hydrocarbons are selected from one or more of vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, and heavy aromatics raffinate; the mineral oils are selected from one or more of coal liquefaction oil, oil sands oil, and shale oil.

[0045] In some embodiments of the present invention, the conditions for the second catalytic conversion reaction include: a reaction temperature of 400-650 °C, preferably 450-600 °C, more preferably 520-580 °C; a reaction pressure of 0.05-1 MPa, preferably 0.1-0.8 MPa; a reaction time of 0.01-100 seconds, preferably 0.1-80 seconds, more preferably 0.2-70 seconds; and a weight ratio of catalyst to heavy oil of (1-100):1, preferably (3-70):1, more preferably (4-30):1.

[0046] The heavy oil catalytic conversion reactor is selected from one of the following: riser, constant linear velocity fluidized bed, constant diameter fluidized bed, upward conveying line, and downward conveying line, or a combination of two types of reactors connected in series; wherein the riser is a constant diameter riser reactor or a variable diameter fluidized bed reactor.

[0047] In some embodiments of the present invention, the first catalyst comprises 1-50% by weight of molecular sieve, 5-99% by weight of inorganic oxide and 0-70% by weight of clay, based on the total weight of the first catalyst.

[0048] The molecular sieve includes mesoporous molecular sieves and / or small-pore molecular sieves; the mesoporous molecular sieve is selected from at least one of ZSM-5 series zeolite and ZRP zeolite; the small-pore molecular sieve is selected from SAPO series zeolite; the inorganic oxide is selected from one or more of silicon dioxide and aluminum oxide; the clay is selected from one or more of kaolinite, hydrous kaolinite, montmorillonite, diatomite, soapstone, rettoitite, sepiolite, attapulgite, hydrotalcite, and bentonite.

[0049] The method further includes: stripping the first and / or second spent catalysts and then feeding them into a regenerator for coke combustion to regenerate a regenerated catalyst; introducing part or all of the regenerated catalyst into the olefin catalytic conversion reactor. In this way, the coke deposits on the first and / or second spent catalysts can be burned to provide energy for high-temperature olefin cracking.

[0050] In some embodiments of the present invention, a portion of the regenerated catalyst can be fed into the heavy oil catalytic conversion reactor to participate in the reaction. This can provide energy for the heavy oil catalytic conversion and regulate the catalyst-to-oil ratio in the heavy oil catalytic conversion reactor.

[0051] A second aspect of the invention provides a reaction system for producing ethylene and propylene, such as... Figure 1 As shown, the system includes: an olefin catalytic conversion reactor 1, a heavy oil catalytic conversion reactor 2, and a regenerator 3; the olefin catalytic conversion reactor 1 includes, from bottom to top, a first riser section, a dense-phase fluidization section, and a dilute-phase section 6; the dense-phase fluidization section of the olefin catalytic conversion reactor 1 is provided with a regenerated catalyst inlet and a catalyst outlet located below the regenerated catalyst inlet, and the dilute-phase section 6 is provided with a cooling medium distributor 5; the heavy oil catalytic conversion reactor 2 includes, from bottom to top, a third riser section, a reaction section, and a fourth riser section; the bottom of the third riser section of the heavy oil catalytic conversion reactor 2 is provided with a catalyst outlet; The regenerator 3 has an oxygen gas inlet and a catalyst inlet at the bottom, and a first regenerated catalyst outlet at the bottom. The regenerated catalyst inlet of the olefin catalytic conversion reactor 1 is connected to the first regenerated catalyst outlet of the regenerator 3, and the catalyst outlet is connected to the extracted catalyst inlet of the heavy oil catalytic conversion reactor 2.

[0052] The system further includes a first settling tank 9 connected to the outlet of the olefin catalytic conversion reactor 1 and a second settling tank 18 connected to the outlet of the heavy oil catalytic conversion reactor 2; the bottom of the first settling tank 9 is provided with a first stripping section 8, and the bottom of the first stripping section 8 is provided with a first catalyst outlet.

[0053] In the above method, after the reaction stream in the olefin catalytic conversion reactor 1 is instantaneously cooled, the first catalyst to be produced overflows directly into the first stripping section 8 for stripping. Since there is no riser section at the reactor outlet, the diameter of the reactor outlet is relatively large, the catalyst overflow velocity is low, and the ejection amount is small, thus rapid separation can be expected.

[0054] In another specific embodiment of the present invention, such as Figure 2 As shown, a second lifting section 7 can also be provided at the outlet of the dilute phase section 6 of the olefin catalytic conversion reactor 1; the outlet of the second lifting section 7 is connected to a rapid separation device; the diameter of the outlet of the second lifting section is reduced, at which time the catalyst velocity is higher, the reaction stream shortens the separation time through the rapid separation device, and after separation, it enters the cyclone separator in the settling tank for further separation, so as to achieve the separation of the catalyst to be generated and the reaction oil and gas. The fine powder of the catalyst to be generated is returned to the settling tank through the material leg of the cyclone separator and flows to the first stripping section.

[0055] Among them, such as Figure 1 and Figure 2 As shown, the bottom of the second settling tank 18 is provided with a second stripping section 20, and the bottom of the second stripping section 20 is provided with a second catalyst outlet.

[0056] The first stripping section 8 has a first catalyst outlet at its bottom; the second stripping section 20 at its bottom has a second catalyst outlet; the catalyst inlet of the regenerator 3 is connected to the first catalyst outlet of the first stripping section 8 and the second catalyst outlet of the second stripping section 20, respectively.

[0057] In some preferred embodiments of the present invention, the regenerator 3 is further provided with a second regenerated catalyst outlet at its lower part, and the heavy oil catalytic conversion reactor 2 is provided with a regenerated catalyst inlet at its lower part of the third lifting section, and the regenerated catalyst inlet of the heavy oil catalytic conversion reactor 2 is connected to the second regenerated catalyst outlet of the regenerator 3.

[0058] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this does not limit the present invention.

[0059] Figure 1 A flowchart illustrating a specific embodiment of the present invention is shown, which is consistent with... Figure 2 , Figure 3 The difference in the specific implementation of the process diagram shown is that the outlet of the dilute phase section of the olefin catalytic conversion reactor is not provided with a second lift section. After the catalyst and reaction stream are cooled, the first raw catalyst overflows directly into the first stripping section 8 in the first settling tank to contact with steam for stripping.

[0060] Figure 2 A flowchart illustrating a specific implementation of the method provided by the present invention, as shown below. Figure 2 As shown, the gaseous olefin-rich feedstock enters the bottom of the first riser section of the olefin catalytic conversion reactor 1 via pipeline 4, ascends along the first riser section, and enters the dense phase fluidization section via gas distributor 5 to contact the first catalyst from pipeline 13 for the first catalytic conversion reaction, yielding the first reaction stream. The first reaction stream enters the dilute phase section 6 and is instantly cooled to the target temperature of 450-530℃ upon contact with the cooling medium. The cooled stream is then introduced into the cyclone separator in the first settling tank 9 at the outlet of the second riser section 7 for gas-solid separation, yielding the first pre-catalyst and the first reaction oil-gas. The first reaction oil-gas enters the gas collection chamber 10, while the catalyst fines return to the first settling tank 9 via the feed leg. The first pre-catalyst in the first settling tank 9 flows to the first stripping section 8, where it contacts the stripping steam. The oil-gas stripped from the first pre-catalyst enters the gas collection chamber 10 after passing through the cyclone separator. The stripped first pre-catalyst enters the regenerator 3 via the pre-catalyst inclined tube 12.

[0061] The dense-phase fluidized section of the olefin catalytic conversion reactor 1 is equipped with a catalyst outlet. Part of the catalyst is accelerated upwards along the dense-phase fluidized section under the action of a pre-lifting medium, while the remaining catalyst enters the bottom of the third lift section of the heavy oil catalytic conversion reactor 2 via pipeline 14. Heavy feedstock oil is injected into reactor 2 via pipeline 15 along with atomized steam, mixing with the existing stream in reactor 2. The heavy feedstock oil undergoes a second catalytic conversion reaction on the hot catalyst and accelerates upwards, yielding a second reaction stream. This second reaction stream enters the cyclone separator in the second settling tank 18 via the fourth lift section 17, separating the spent catalyst from the reaction stream to obtain a second spent catalyst and a second reaction oil-gas mixture. The second reaction oil-gas mixture enters the gas collecting chamber 19, while the catalyst powder returns to the settling tank via the feed leg. The second spent catalyst in the second settling tank 18 flows to the second stripping section 20 to contact the stripping steam. The oil-gas stripped from the second spent catalyst is separated by the cyclone separator and enters the gas collecting chamber 19. The stripped second spent catalyst then enters the regenerator 3 via the spent catalyst inclined tube 21.

[0062] The main air enters the regenerator 3 via the main air distributor 22, burning off the coke on the deactivated catalyst and regenerating it to obtain a regenerated catalyst. The flue gas enters the flue gas fan via pipeline. The regenerated catalyst is divided into at least two streams: part enters reactor 1 via pipeline 13, and part enters reactor 2 via pipeline 16.

[0063] The first and second reaction oil and gas enter the first separation unit 23 via oil and gas pipeline 11 for separation. The separated hydrogen, methane, ethane and other ethylene-lean dry gases are drawn out via pipeline 28, ethylene is drawn out via pipeline 29, propylene is drawn out via pipeline 30, and C5 and above distillate oil with an initial boiling point of less than 150℃ is drawn out via pipeline 25. The C5 and above distillate oil enters the second separation unit 24 for alkane and olefin separation. The olefin-rich stream is introduced into the olefin catalytic conversion reactor 1 via pipeline 26 for further reaction, and the alkanes are drawn out via pipeline 27.

[0064] Figure 3 A flowchart illustrating a second specific embodiment of the present invention is shown; see [link / reference]. Figure 3 The flowchart diagram illustrates the specific implementation method. Figure 2 The difference in the specific implementation method shown in the flowchart is as follows: the second reaction oil and gas of the heavy oil catalytic conversion reactor 2 enters the first separation unit 23 for separation via oil and gas pipeline 11-a. The low-carbon gas phase product obtained by separation is led out via pipeline 28. C5 and above distillate oil with an initial boiling point of less than 150℃ is introduced into the second separation unit 24 via pipeline 25 for alkane and olefin separation. The alkane obtained by separation is led out via pipeline 27. The olefin-rich stream is introduced into the olefin catalytic conversion reactor 1 via pipeline 26 for further reaction.

[0065] The first reaction oil and gas from the olefin catalytic conversion reactor 1 enters the first reaction oil and gas inlet pipeline 11-b and the gaseous stream from the second separation unit 24 together into the third separation unit 31 for further separation. The resulting ethylene is led out through pipeline 29 and propylene is led out through pipeline 30.

[0066] The present invention will be further described in detail below through examples. All raw materials used in the examples are commercially available.

[0067] The commercial brand name of the first and second catalysts used in the embodiments and comparative examples of this invention is TCC-1, which is an industrial product manufactured by Sinopec Catalyst Qilu Branch. The properties of the catalysts are shown in Table 1.

[0068] Table 1

[0069] The olefin-rich feedstocks used in the embodiments and comparative examples of this invention are 1-pentene and 1-hexene, and the properties of the heavy oil feedstock are shown in Table 2.

[0070] Table 2

[0071] Example 1 This embodiment follows Figure 2 The process shown was tested, with the catalytic conversion of heavy oil carried out in a medium-sized unit of riser reactor and the catalytic conversion of 1-pentene carried out in a turbulent fluidized bed reactor; the weight ratio of 1-pentene to heavy oil feedstock was 1:9.

[0072] 1-Pentene and a first catalyst at 650 °C are in contact at the bottom of the dense-phase bed section of an olefin catalytic conversion reactor to carry out the first catalytic conversion reaction. The reaction stream is then in contact with gasoline at 40 °C in the dilute-phase section and rapidly cooled to 500 °C within 1 second. The conditions for the first catalytic conversion reaction include: a reaction temperature of 650 °C, a reaction pressure of 0.12 MPa, a residence time of 1-pentene in the dense-phase bed section of 1 s, and a weight ratio of the first catalyst to 1-pentene of 30:1. Catalyst accounting for 10% by weight of the catalyst circulating in the olefin catalytic conversion reactor is extracted from the dense-phase bed section of the olefin catalytic conversion reactor and fed into the heavy oil catalytic conversion reactor. The heavy feedstock and catalyst are in contact in the heavy oil catalytic conversion reactor to carry out a second catalytic conversion reaction. The conditions for the second catalytic conversion reaction are as follows: reaction temperature is 530 ℃, reaction pressure is 0.12 MPa, reaction time is 3.5 s, and the weight ratio of catalyst to heavy feedstock is 15:1. The first and second reaction oil and gas are introduced together into a combined separation system to obtain products including ethylene, propylene, a stream rich in C5-C7 olefins, and remaining distillate oils. The stream rich in C5-C7 olefins is introduced into the bottom of the dense-phase bed section of the olefin catalytic conversion reactor for further reaction. The stream rich in C5-C7 olefins comprises 50% by weight of C5 olefins, 25% by weight of C6 olefins, and 25% by weight of C7 olefins.

[0073] After separation, the spent catalyst is regenerated by oxygen-containing coking and then returned to the olefin catalytic conversion reactor and the heavy oil catalytic conversion reactor for recycling.

[0074] The reaction conditions and product distribution are listed in Table 3.

[0075] Comparative Example 1 The method of Comparative Example 1 is basically similar to that of Example 1, except that: 1-pentene is not introduced into the olefin catalytic conversion reactor and the C5-C7 olefin-rich stream separated from the reaction product is not returned to the olefin catalytic conversion reactor for further reaction, that is, only the heavy feedstock oil is in contact with the catalyst in the heavy oil catalytic conversion reactor to carry out the second catalytic conversion reaction. The reaction conditions and product distribution are listed in Table 3.

[0076] Example 2 The method in Example 2 is basically similar to that in Example 1, except that 1-pentene is not introduced into the olefin catalytic conversion reactor, and the C5-C7 olefin-rich stream separated from the reaction product is returned to the olefin catalytic conversion reactor for further reaction. The reaction conditions and product distribution are listed in Table 3.

[0077] Comparative Example 2 The method of Comparative Example 2 is basically similar to that of Comparative Example 1, except that the reaction temperature of the second catalytic conversion reaction is 610 °C, the catalyst-to-oil ratio is 16.9, and the reaction conditions and product distribution are listed in Table 3.

[0078] Comparative Example 3 The method of Comparative Example 3 is basically similar to that of Example 1, except that the dense phase bed of the olefin catalytic conversion reactor does not have a catalyst outlet, that is, all the catalyst in the heavy oil catalytic conversion reactor comes from the regenerator. The specific reaction conditions and product distribution are listed in Table 3.

[0079] Table 3

[0080] As can be seen from the table above, the method of the present invention can significantly improve the yield of ethylene and propylene.

[0081] Comparing Example 1 and Comparative Example 1, it can be seen that coupling olefin catalytic conversion and heavy oil catalytic conversion is beneficial for producing more ethylene and propylene.

[0082] In Example 2, since olefins were not used as raw materials, the C5-C7 olefins in the separated product were introduced into the olefin catalytic conversion reactor for reprocessing. Due to the small amount of C5-C7 olefins, the amount of ethylene and propylene produced was reduced.

[0083] In Comparative Example 3, when the catalyst was not removed from the dense-phase bed of the olefin catalytic conversion reactor, the yields of both ethylene and propylene decreased, and the amount of coke generated was greater.

[0084] Example 3 The method in Example 3 is basically similar to that in Example 1, except that the reaction temperature of the first catalytic conversion reaction is 600 °C and the reaction temperature of the second catalytic conversion reaction is 550 °C. The specific reaction conditions and product distribution are listed in Table 4.

[0085] Example 4 The method in Example 4 is basically similar to that in Example 1, except that the feedstock for the olefin catalytic conversion reactor is 1-hexene; the reaction temperature of the first catalytic conversion reaction is 600 °C; and the specific reaction conditions and product distribution are listed in Table 4.

[0086] Example 5 The method in Example 5 is basically similar to that in Example 1, except that the ratio of 1-pentene to heavy oil feedstock is 1:4. The specific reaction conditions and product distribution are listed in Table 4.

[0087] Example 6 The method in Example 6 is basically similar to that in Example 1, except that the catalyst density of the dense-phase bed in the olefin catalytic conversion reactor is 400 kg·m³. -3 The specific reaction conditions and product distribution are listed in Table 4.

[0088] Example 7 The method of Example 7 is basically similar to that of Example 1, except that: the reaction temperature of the first catalytic conversion reaction is 600 °C; the residence time of 1-pentene in the dense phase bed in the olefin catalytic conversion reactor is 2 seconds, and the reaction time in the heavy oil catalytic conversion reactor is 5 seconds; the specific reaction conditions and product distribution are listed in Table 4.

[0089] Table 4

[0090] The data in the table above show that when the reaction temperature of the olefin catalytic conversion reactor is reduced, the yields of both ethylene and propylene decrease; while when the amount of olefin used is increased and the catalyst density in the appropriate olefin catalytic conversion reactor is increased, the yields of both ethylene and propylene are improved.

[0091] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of 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 protection scope of the present invention.

[0092] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0093] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A catalytic conversion method for producing ethylene and propylene, characterized in that, The method includes: The olefin-rich feedstock is fed into the dense-phase bed section of the olefin catalytic conversion reactor to contact the first catalyst for the first catalytic conversion reaction. The reaction stream is then instantaneously cooled to a target temperature of 450-530 °C in the dilute-phase section of the reactor. The cooled stream is then subjected to gas-solid separation at the reactor outlet to obtain the first reaction oil and gas and the first catalyst to be generated. The temperature of the first catalyst before the reaction is higher than or equal to 650 °C. A portion of the first catalyst is extracted from the dense-phase bed section of the olefin catalytic conversion reactor and fed into the heavy oil catalytic conversion reactor as the second catalyst. Heavy oil is introduced into the heavy oil catalytic conversion reactor to contact the second catalyst for the second catalytic conversion reaction. The reaction stream is then separated to obtain the second reaction oil and gas and the second catalyst to be generated. The first and second reaction oil gases are separated to obtain ethylene, propylene, liquefied petroleum gas, butene, and C-containing compounds. 5+ Olefin stream, and make the C-containing 5+ The olefin stream is returned to the olefin catalytic conversion reactor to continue the reaction.

2. The catalytic conversion method according to claim 1, wherein, The time for the reacted material to cool down to the target temperature is 0.1-2 seconds, preferably 0.5-1 seconds; Optionally, the instantaneous cooling method includes: contacting the post-reaction stream with a cooling medium injected into the dilute phase section of the reactor for cooling; the cooling medium is selected from one or more of liquefied petroleum gas, crude gasoline, coking gasoline, and stabilized gasoline.

3. The catalytic conversion method according to claim 1, wherein, The density of the first catalyst in the dense-phase bed section is 300-750 kg / m³. 3 The preferred value is 350-500 kg / m³. 3 ; The first catalyst extracted from the dense-phase bed section of the olefin catalytic conversion reactor accounts for 5-40% by weight of the catalyst recycling amount in the olefin catalytic conversion reactor, preferably 5-20% by weight. Optionally, the first catalytic conversion reaction conditions include: a reaction temperature of 550-800 °C in the dense phase bed section, preferably 600-700 °C; a reaction pressure of 0.02-1 MPa, preferably 0.1-0.8 MPa; a residence time of the olefin-rich feedstock in the dense phase bed section of 0.01-10 seconds, preferably 0.1-3 seconds; and a weight ratio of the first catalyst to the olefin-rich feedstock of (1-200):1, preferably (5-50):1, more preferably (10-30):

1. Optionally, the conditions for the second catalytic conversion reaction include: a reaction temperature of 400-650 °C, preferably 450-600 °C, more preferably 520-580 °C; a reaction pressure of 0.05-1 MPa, preferably 0.1-0.8 MPa; a reaction time of 0.01-100 seconds, preferably 0.1-80 seconds, more preferably 0.2-70 seconds; and a weight ratio of catalyst to heavy oil of (1-100):1, preferably (3-70):1, more preferably (4-30):

1.

4. The catalytic conversion method according to claim 1, wherein, The weight ratio of the olefin-rich raw material to the heavy oil is 1:(1-50), preferably 1:(1-20), and more preferably 1:(2-10). The olefin-rich raw material contains 60-100% by weight of olefins, preferably 90-100% by weight, and more preferably pure olefin raw material. The olefins in the olefin-rich raw material are selected from C5-C7 olefins; Optionally, the olefin-rich feedstock is derived from at least one of the following: C5 or higher fractions produced by an alkane dehydrogenation unit, C5 or higher fractions produced by a refinery catalytic cracking unit, C5 or higher fractions produced by an ethylene plant steam cracking unit, olefin-rich fractions with C5 or higher as byproducts of MTO, and olefin-rich fractions with C5 or higher as byproducts of MTP. Optionally, the heavy oil is selected from petroleum hydrocarbons and / or mineral oils; the petroleum hydrocarbons are selected from one or more of vacuum gas oil, atmospheric gas oil, coking gas oil, deasphalted oil, vacuum residue, atmospheric residue, and heavy aromatics raffinate; the mineral oils are selected from one or more of coal liquefaction oil, oil sands oil, and shale oil.

5. The catalytic conversion method according to claim 1, wherein, Based on the total weight of the first catalyst, the first catalyst comprises 1-50% by weight of molecular sieve, 5-99% by weight of inorganic oxide and 0-70% by weight of clay. Optionally, the molecular sieve includes a mesoporous molecular sieve and / or a microporous molecular sieve; The mesoporous molecules are selected from at least one of the ZSM-5 series zeolites and ZRP zeolites; the microporous molecules are selected from the SAPO series zeolites; the inorganic oxides are selected from one or more of silicon dioxide and aluminum oxide; the clay is selected from one or more of kaolin, hydrous kaolin, montmorillonite, diatomaceous earth, soapstone, rettosite, sepiolite, attapulgite, hydrotalcite, and bentonite.

6. The catalytic conversion method according to claim 1, wherein, The olefin catalytic conversion reactor is selected from one of a bubbling fluidized bed reactor and a turbulent fluidized bed reactor, or a combination of two reactors in series, preferably a turbulent fluidized bed reactor; The heavy oil catalytic conversion reactor is selected from one of the following: riser, constant linear velocity fluidized bed, constant diameter fluidized bed, upward conveying line, and downward conveying line, or a combination of two types of reactors connected in series; wherein, the riser is a constant diameter riser reactor or a variable diameter fluidized bed reactor.

7. The catalytic conversion method according to claim 1, wherein, The method further includes: stripping the first spent catalyst and / or the second spent catalyst and then sending them to a regenerator for coking and regeneration to obtain a regenerated catalyst; Introduce part or all of the regenerated catalyst into the olefin catalytic conversion reactor; Preferably, a portion of the regenerated catalyst is fed into the heavy oil catalytic conversion reactor to participate in the reaction.

8. The catalytic conversion method according to claim 1, wherein, The dense phase bed section of the olefin catalytic conversion reactor is provided with a catalyst outlet, and the distance between the catalyst outlet and the bottom of the dense phase bed section is 1 / 10-1 / 2, preferably 1 / 10-1 / 4, of the height of the dense phase bed section. Optionally, the distance between the catalyst inlet of the olefin catalytic conversion reactor and the top of the dense phase bed section is 1 / 10 to 1 / 2 of the height of the dense phase bed section, preferably 1 / 10 to 1 / 4.

9. A reaction system for producing ethylene and propylene, characterized in that, The system includes: an olefin catalytic conversion reactor (1), a heavy oil catalytic conversion reactor (2), and a regenerator (3). The olefin catalytic conversion reactor (1) includes, from bottom to top, a first lifting section, a dense phase fluidization section and a dilute phase section (6). The dense phase fluidized section of the olefin catalytic conversion reactor (1) is provided with a regenerated catalyst inlet and a catalyst outlet located below the regenerated catalyst inlet, and the dilute phase section (6) is provided with a cooling medium distributor (5). The heavy oil catalytic conversion reactor (2) includes, from bottom to top, a third lifting section, a reaction section and a fourth lifting section (17); the bottom of the third lifting section of the heavy oil catalytic conversion reactor (2) is provided with a catalyst extraction inlet; The regenerator (3) is provided with an oxygen gas inlet and a catalyst inlet at the bottom, and a first regenerated catalyst outlet at the bottom. The regeneration catalyst inlet of the olefin catalytic conversion reactor (1) is connected to the first regeneration catalyst outlet of the regenerator (3), and the catalyst outlet is connected to the catalyst outlet of the heavy oil catalytic conversion reactor (2).

10. The system according to claim 9, wherein, The system also includes a first settling tank (9) connected to the outlet of the olefin catalytic conversion reactor (1) and a second settling tank (18) connected to the outlet of the heavy oil catalytic conversion reactor (2). The first settling device (9) is provided with a first stripping section (8) at the bottom, and the first stripping section (8) is provided with a first catalyst outlet at the bottom; The bottom of the second settling tank (18) is provided with a second stripping section (20), and the bottom of the second stripping section (20) is provided with a second catalyst outlet; The inlet of the regenerator (3) is connected to the first outlet of the first stripping section (8) and the second outlet of the second stripping section (20), respectively. Preferably, the outlet of the dilute phase section (6) of the olefin catalytic conversion reactor (1) is further provided with a second lifting section (7); the outlet of the second lifting section (7) is connected to a rapid separation device; Preferably, the regenerator (3) is further provided with a second regenerated catalyst outlet at the lower part, and the heavy oil catalytic conversion reactor (2) is provided with a regenerated catalyst inlet at the lower part of the third lifting section. The regenerated catalyst inlet of the heavy oil catalytic conversion reactor (2) is connected to the second regenerated catalyst outlet of the regenerator (3).

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