Catalytic conversion method for producing ethylene and propylene from heavy hydrocarbon oil

Abstract

The invention relates to a catalytic conversion method for producing ethylene and propylene from heavy hydrocarbon oil, which comprises the following steps: introducing modified heavy oil into a first reactor to contact with a first catalytic conversion catalyst for a first catalytic conversion reaction to obtain a first oil agent mixture; introducing the first oil agent mixture into a second reactor to carry out a second catalytic conversion reaction, and carrying out gas-solid separation on the material flow after the reaction to obtain reaction oil gas and a spent catalyst; the first catalytic conversion catalyst includes an MPZ hierarchical pore molecular sieve. According to the method, the heavy hydrocarbon oil is separated and modified to remove most asphaltene and part of colloid in the heavy hydrocarbon oil, the modified heavy hydrocarbon oil is subjected to catalytic conversion by using the MPZ molecular sieve catalyst, and multi-reactor partition coupling and regulation operation are adopted, so that green coke can be reduced, and the yield of ethylene and propylene can be increased.

Description

Technical Field

[0001] This invention relates to the field of petrochemicals, specifically to a catalytic conversion method for producing ethylene and propylene from heavy hydrocarbon oils. Background Technology

[0002] Ethylene and propylene are important basic chemical raw materials. Currently, the production of ethylene and propylene mainly relies on tubular steam cracking, using feedstocks including light petroleum hydrocarbons such as ethane, propane, butane, naphtha, light diesel oil, and condensate. Naphtha dominates the steam cracking feedstock, accounting for 50-55%, ethane accounts for 25-30%, while propane, butane, light diesel oil, and condensate oil each account for less than 10%.

[0003] As crude oil becomes increasingly heavier, the supply of light petroleum hydrocarbons can no longer meet the demand for steam cracking. Therefore, the technology of producing low-carbon olefins such as ethylene and propylene using heavy petroleum hydrocarbons is receiving increasing attention. For example, CN1218786A discloses a catalytic thermal cracking method for producing ethylene and propylene. In a riser or downflow reactor, heavy petroleum hydrocarbons are reacted with a catalyst containing layered column clay molecular sieves and / or five-membered ring high-silica molecular sieves modified with phosphorus and aluminum or magnesium or calcium. By adjusting the reaction conditions, the yields of ethylene and propylene in the products both exceed 18% by weight.

[0004] CN1393510A discloses a method for catalytic conversion of heavy petroleum hydrocarbons to increase the production of ethylene and propylene. The method involves contacting and reacting the petroleum hydrocarbon feedstock with a catalyst containing a five-membered ring high-silica molecular sieve in a riser or fluidized bed reactor. Water vapor is injected in stages as the oil-agent mixture moves upward along the reactor. This method can also alleviate the hydrothermal deactivation of the catalyst to some extent.

[0005] CN102443423A discloses a method for catalytic conversion of petroleum hydrocarbons to produce high yields of ethylene, propylene, and light aromatics. Preheated petroleum hydrocarbon feedstock and a pyrolysis catalyst are introduced into the bottom of a fluidized bed reactor. The mixture of the petroleum hydrocarbon feedstock and the pyrolysis catalyst passes sequentially from bottom to top through a pre-lifting zone, a first reaction zone, a quenching zone, and a second reaction zone of the fluidized bed reactor under the action of a lifting medium. The reaction occurs in the first reaction zone, the quenching zone, and the second reaction zone under catalytic pyrolysis conditions. By controlling the reaction temperature in each reaction zone, and by controlling the reaction temperature in the first reaction zone to be 20-150°C higher than that in the second reaction zone, higher yields of ethylene, propylene, and light aromatics can be obtained.

[0006] CN116083122A discloses a method for producing ethylene and propylene from heavy hydrocarbons. The method includes contacting a heavy hydrocarbon feedstock as a first feedstock with a catalytic cracking catalyst in a fluidized bed catalytic cracking unit to carry out a catalytic cracking reaction, and removing the mixed C4 and C4 components from the catalytic cracking reaction products. 5+ Catalytic cracking of naphtha fractions, hydrogenation of the light cycle oil obtained from fractionation of catalytic cracking and catalytic cracking products, and catalytic cracking and recycling of the hydrogenation products of the heavy cycle oil and light cycle oil obtained from fractionation are beneficial to optimizing the product structure. This can maximize the production yield of ethylene and propylene while reducing the generation of by-products, thereby increasing the utilization rate of carbon atoms.

[0007] However, in order to balance heavy oil conversion and increased ethylene and propylene production, existing technologies typically require relatively mild reaction conditions to suppress coking in the unit, and the yield and selectivity of ethylene in heavy oil catalytic conversion products need to be further improved. Summary of the Invention

[0008] The purpose of this invention is to improve the yield of ethylene and propylene and reduce coking.

[0009] To achieve the above objectives, the present invention provides a catalytic conversion method for producing ethylene and propylene from heavy hydrocarbon oil, the method comprising: The modified heavy oil is introduced into a first reactor and contacted with a first catalytic conversion catalyst to carry out a first catalytic conversion reaction, obtaining a first oil-catalyst mixture. The first oil-catalyst mixture is then introduced into a second reactor to carry out a second catalytic conversion reaction. The reaction stream is subjected to gas-solid separation to obtain reacted oil gas and a spent catalyst. The reacted oil gas is further separated to obtain ethylene, propylene, C4 fraction, and light gasoline fraction products. The spent catalyst is then regenerated by coking to obtain a regenerated catalyst, and part or all of the regenerated catalyst is recycled back to the first reactor. The modified heavy oil contains asphaltene at a content of 0.01-0.2% by weight. The first catalytic conversion catalyst comprises an MPZ multi-level porous molecular sieve.

[0010] Optionally, the modified heavy oil has properties that satisfy at least one of the following conditions: i. asphaltenes content is 0.01-0.1% by weight; ii. gum content is 0.5-12.0% by weight, preferably 1-10.0% by weight; iii. carbon residue content is 0.2-2.0% by weight; iv. total metal content is less than 1.0 ppm.

[0011] Optionally, the method further includes: contacting heavy hydrocarbon oil with an organic solvent to perform deasphalting treatment, obtaining the modified heavy oil and de-oiled asphalt; the conditions for the deasphalting treatment include: a reaction temperature of 10-200 ℃, preferably 20-180 ℃; a reaction pressure of 1.0-15.0 MPa, preferably 2.0-13.0 MPa; a weight ratio of organic solvent to heavy hydrocarbon oil of 1-20, preferably 3-10; the organic solvent is selected from one or more of C3-C6 alkanes, preferably at least one of propane, n-butane and n-pentane; optionally, the content of gum in the heavy hydrocarbon oil is 5.0-20.0% by weight, and the content of asphaltenes is 0.5-5.0% by weight; the heavy hydrocarbon oil is selected from one or a mixture of several of vacuum gas oil, atmospheric residue, vacuum residue, hydrotreated vacuum gas oil and hydrotreated atmospheric residue.

[0012] Optionally, the first catalytic conversion catalyst comprises a molecular sieve mixture, a heat-resistant inorganic oxide, and clay. Based on the total weight of the first catalytic conversion catalyst, the first catalytic conversion catalyst contains 1-60% by weight of the molecular sieve mixture, 5-99% by weight of the heat-resistant inorganic oxide, and 0-70% by weight of the clay, and the sum of the weight contents of each component is 100%. Based on the total weight of the molecular sieve mixture, the molecular sieve mixture contains 80-100% by weight of the MPZ hierarchical porous molecular sieve.

[0013] Optionally, in the surface XPS elemental analysis of the MPZ multi-level porous molecular sieve, n1 / n2 is less than or equal to 0.08, where n1 represents the number of moles of phosphorus in the MPZ multi-level porous molecular sieve, and n2 represents the total number of moles of silicon and aluminum in the MPZ multi-level porous molecular sieve.

[0014] Optionally, after hydrothermal aging of MPZ hierarchical porous molecular sieve at 800℃ and 100% steam for 17h, the NH3-TPD spectrum shows that the area of ​​strong acid center peaks with desorption temperatures above 200℃ accounts for more than or equal to 45% of the total acid center peak area.

[0015] Optionally, the conditions for the first catalytic conversion reaction include: a reaction temperature of 550-680℃, preferably 570-660℃; a weight ratio of the first catalytic conversion catalyst to the modified heavy oil of 8-40, preferably 10-30; an oil-gas residence time of 0.5-6 s, preferably 0.8-5 s; and a reaction pressure of 0.15-0.30 MPa, preferably 0.17-0.25 MPa. Optionally, the first reactor is selected from a riser reactor, a fluidized bed reactor, a downflow conveyor reactor, or a composite reactor composed of multiple of the above reactors connected in series and / or in parallel, preferably a riser reactor.

[0016] Optionally, the reaction conditions for the second catalytic conversion include: a reaction temperature of 570-650 °C, preferably 575-645 °C; and a weight hourly space velocity of 1-30 h⁻¹. -1 Preferably 3-20 h -1 The reaction pressure is 0.15-0.30 MPa, preferably 0.15-0.20 MPa; optionally, the second reactor is selected from one or more of the following: a dispersed fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, and a dense phase fluidized bed reactor.

[0017] Optionally, the method further includes: introducing the C4 fraction and / or the light gasoline fraction into a third reactor to undergo a third catalytic conversion reaction with the second catalytic conversion catalyst to obtain a second oil-fuel mixture; introducing the second oil-fuel mixture and the first oil-fuel mixture together into the second reactor for reaction; and dividing the regenerated catalyst into at least two streams and introducing them into the first reactor and the third reactor respectively; Optionally, the second catalytic conversion catalyst comprises a molecular sieve mixture, heat-resistant inorganic oxides, and clay, and based on the total weight of the second catalytic conversion catalyst, the second catalytic conversion catalyst contains 1-60% by weight of the molecular sieve mixture, 5-99% by weight of the heat-resistant inorganic oxides, and 0-70% by weight of the clay, and the sum of the weight contents of each component is 100%; based on the total weight of the molecular sieve mixture, the molecular sieve mixture contains 80-100% by weight of the MPZ hierarchical porous molecular sieve.

[0018] Optionally, the third reactor is provided with a first reaction zone and a second reaction zone from bottom to top; the C4 fraction is introduced into the first reaction zone for reaction; and / or the light gasoline fraction is introduced into the second reaction zone for reaction; the reaction conditions in the first reaction zone include: a reaction temperature of 620-680℃, preferably 630-680℃; a weight ratio of the second catalytic conversion catalyst to the C4 fraction of 20-80, preferably 30-70; a residence time of 0.5-1.5s, preferably 0.5-1.0s; and a reaction pressure of 0.15-0.30MPa, preferably 0.15-0.20MPa. MPa; and / or the reaction conditions in the second reaction zone include: a reaction temperature of 610-660℃, preferably 620-650℃; a weight ratio of the second catalytic conversion catalyst to light gasoline fraction of 20-80, preferably 30-70; an oil-gas residence time of 0.5-1.5s, preferably 0.5-1.0s; and a reaction pressure of 0.15-0.30MPa, preferably 0.15-0.20MPa; optionally, the third reactor is selected from a riser reactor, a fluidized bed reactor, a downflow conveyor reactor, or a composite reactor composed of multiple of the above reactors connected in series and / or in parallel, preferably a riser reactor.

[0019] Through the above technical solution, the present invention has the following beneficial effects: (1) The present invention uses modified heavy hydrocarbon oil for catalytic conversion. By separating and modifying the heavy hydrocarbon oil to remove most of the asphaltenes and some of the gums, coking can be reduced and the yield of ethylene and propylene can be increased. At the same time, the modified heavy hydrocarbon oil contains less residual carbon and metal, which can further reduce the coke yield. (2) The present invention uses MPZ molecular sieve catalyst to catalytically convert the above-mentioned modified heavy hydrocarbon oil, and adopts multi-reactor partition coupling and control operation, which is beneficial to improve the selectivity of ethylene and propylene, can significantly reduce coking, and extend the production cycle of heavy oil to ethylene and propylene.

[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 embodiment of the catalytic conversion method of the present invention.

[0022] Figure 2 This is a flowchart illustrating a specific embodiment of the catalytic conversion method of the present invention.

[0023] Explanation of reference numerals in the attached figures: 1. First reactor; 11. First regeneration pipe; 12. First regeneration pipe control valve; 13. Pipeline; 14. Oil distributor; 2. Second reactor; 21. First delivery pipe; 3. Third reactor; 31. Second regeneration pipe; 32. Second regeneration pipe control valve; 33. Pipeline; 34. Pipeline; 4. Settler; 41. First-stage cyclone separator; 42. Second-stage cyclone separator; 43. Reaction oil and gas pipeline; 5. Stripper; 51. Stripping baffle; 52. Catalyst delivery pipe; 53. Catalyst delivery pipe control valve; 6. Regenerator; 61. Main air inlet; 62. Flue gas outlet. Detailed Implementation

[0024] 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.

[0025] In this invention, unless otherwise specified, all pressures mentioned refer to absolute pressure.

[0026] This invention provides a catalytic conversion method for producing ethylene and propylene from heavy hydrocarbon oil, the method comprising: The modified heavy oil is introduced into the first reactor and contacted with the first catalytic conversion catalyst to carry out the first catalytic conversion reaction, thereby obtaining the first oil-catalyst mixture. The first oil-agent mixture is introduced into the second reactor to carry out the second catalytic conversion reaction. The reaction stream is then subjected to gas-solid separation to obtain the reaction oil-gas and the catalyst to be generated. The reaction oil and gas are separated to obtain ethylene, propylene, C4 fraction and light gasoline fraction products; The spent catalyst is regenerated by coking to obtain a regenerated catalyst, and part or all of the regenerated catalyst is recycled back to the first reactor. The modified heavy oil contains asphaltene at a content of 0.01-0.2% by weight; the first catalytic conversion catalyst comprises MPZ multi-level porous molecular sieve.

[0027] Through the above technical solution, this invention uses modified heavy oil with low asphaltene content for catalytic conversion, which can reduce coking and better promote heavy oil conversion, thereby increasing the yield of ethylene and propylene. This invention employs multi-reactor zone coupling and control operation, and uses MPZ molecular sieve catalysts for the catalytic conversion of the above-mentioned modified heavy hydrocarbon oil, which is beneficial for improving the selectivity of ethylene and propylene, significantly reducing coking, and extending the production cycle of ethylene and propylene from heavy oil.

[0028] In this invention, the heavy hydrocarbon oil contains 5-20% by weight of gum and 0.5-5.0% by weight of asphaltenes. Specifically, the heavy hydrocarbon oil can be selected from one or a mixture of several of vacuum gas oil, atmospheric residue, vacuum residue, hydrotreated vacuum gas oil, and hydrotreated atmospheric residue. Heavy hydrocarbon oil contains gum, asphaltenes, and other components, which are difficult to convert during catalytic cracking and are prone to coking. This invention removes most of the asphaltenes and some gums from the heavy hydrocarbon oil by separation and upgrading, while also removing most of the residual carbon and metals, to obtain upgraded heavy hydrocarbon oil.

[0029] The method for upgrading and deasphalting heavy hydrocarbon oil in this invention is selected from one or a combination of several separation methods such as solvent deasphalting, adsorption, distillation, and extraction.

[0030] In one embodiment, the modification method includes contacting heavy hydrocarbon oil with an organic solvent to perform deasphalting treatment, thereby obtaining the modified heavy oil and deoiled asphalt; the organic solvent is a low-carbon alkane, specifically selected from one or more of C3-C6 alkanes, preferably at least one selected from propane, n-butane and n-pentane.

[0031] In one specific embodiment, the conditions for the above-mentioned deasphalting treatment may include: a reaction temperature of 10-200℃, preferably 20-180℃; a reaction pressure of 1.0-15.0 MPa, preferably 2.0-13.0 MPa; and a weight ratio of organic solvent to heavy hydrocarbon oil of 1-20, preferably 3-10.

[0032] In some embodiments of the present invention, the yield of deasphalted oil obtained by solvent deasphalting of heavy hydrocarbon oil is greater than 70%, preferably greater than 80%; compared with heavy hydrocarbon oil, the asphalt removal rate of the deasphalted oil is greater than 60%, preferably greater than 80%; and the gum removal rate is greater than 30%, preferably greater than 40%.

[0033] In addition, compared with heavy hydrocarbon oil, the deasphalted oil has a carbon removal rate of more than 50%, preferably more than 60%; and a heavy metal removal rate of more than 60%, preferably more than 70%.

[0034] In some embodiments of the present invention, heavy hydrocarbon oil is modified by deasphalting treatment, and the modified heavy oil satisfies at least one of the following conditions: i. Asphalt content is 0.01-0.1% by weight; ii. The gum content is 0.5-12.0% by weight, preferably 1-10.0% by weight; iii. The residual char content is 0.2-2.0% by weight; iv. Total metal content is less than 1.0 ppm.

[0035] De-oiled asphalt obtained by modifying heavy hydrocarbon oil is generally used as road asphalt product, or it can be refined and returned to the solvent deasphalting unit.

[0036] In some embodiments of the present invention, the first catalytic conversion catalyst comprises a molecular sieve mixture, a heat-resistant inorganic oxide, and clay. Based on the total weight of the first catalytic conversion catalyst, the first catalytic conversion catalyst contains 1-60% by weight of the molecular sieve mixture, 5-99% by weight of the heat-resistant inorganic oxide, and 0-70% by weight of clay, and the sum of the weight contents of each component is 100%. Based on the total weight of the molecular sieve mixture, the molecular sieve mixture contains 80-100% by weight of the MPZ hierarchical porous molecular sieve.

[0037] In this invention, the MPZ hierarchical porous molecular sieve is a phosphorus- and metal-containing hierarchical porous ZSM-5 molecular sieve, in which phosphorus is fully coordinated with the framework aluminum, which can fully protect the framework aluminum.

[0038] In some embodiments of the present invention, in the surface XPS elemental analysis of the MPZ multi-level porous molecular sieve, n1 / n2 is less than or equal to 0.08, where n1 represents the number of moles of phosphorus in the MPZ multi-level porous molecular sieve, and n2 represents the total number of moles of silicon and aluminum in the MPZ multi-level porous molecular sieve.

[0039] In some embodiments of the present invention, the MPZ hierarchical porous molecular sieve exhibits good hydrothermal stability. Specifically, after hydrothermal aging at 800°C and 100% steam for 17 hours, the NH3-TPD spectrum of the MPZ hierarchical porous molecular sieve shows that the area of ​​strong acid centers with desorption temperatures above 200°C accounts for greater than or equal to 45% of the total area of ​​acid centers, preferably between 45% and 60%, indicating a high retention rate of strong acid centers. This molecular sieve can increase the production of liquefied petroleum gas, improve the yield of low-carbon olefins, and produce more high-value-added products. The preparation method of the MPZ hierarchical porous molecular sieve can be found in CN113526519A and CN14715911A.

[0040] In some embodiments of the present invention, the first reactor is selected from a riser reactor, a fluidized bed reactor, a downflow conveyor reactor, or a composite reactor composed of multiple such reactors connected in series and / or in parallel, preferably a riser reactor. In the present invention, the riser reactor is one or more of a constant-diameter riser reactor, a constant-linear-velocity riser reactor, and a variable-diameter riser reactor.

[0041] In some embodiments of the present invention, the conditions for the first catalytic conversion reaction may include: a reaction temperature of 550-680°C; a weight ratio of the first catalytic conversion catalyst to the reformed heavy oil of 8-40; an oil-gas residence time of 0.5-6 s; and a reaction pressure of 0.15-0.30 MPa.

[0042] In some preferred embodiments of the present invention, the conditions for the first catalytic conversion reaction include: a reaction temperature of 570-660°C; a weight ratio of the first catalytic conversion catalyst to the reformed heavy oil of 10-30; an oil-gas residence time of 0.8-5 s; and a reaction pressure of 0.17-0.25 MPa.

[0043] The first reactor may also be injected with a diluent to reduce the partial pressure of the hydrocarbon feedstock. The weight ratio of the diluent to the first feedstock is 0.1-0.4:1, preferably 0.15-0.3:1. The diluent may be selected from one or a mixture of several of water vapor, low-carbon alkanes and nitrogen, preferably water vapor.

[0044] In some embodiments of the present invention, the second reactor may be selected from one or more of the following: a dispersed fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, and a dense phase fluidized bed reactor.

[0045] In some embodiments of the present invention, the reaction conditions for the second catalytic conversion may include: a reaction temperature of 570-650 °C; and a weight hourly space velocity of 1-30 h⁻¹. -1 The reaction pressure is 0.15-0.30 MPa.

[0046] In some preferred embodiments of the present invention, the reaction conditions for the second catalytic conversion may include: a reaction temperature of 575-645 °C; and a weight hourly space velocity of 3-20 h⁻¹. -1 The reaction pressure is 0.15-0.20 MPa.

[0047] In some embodiments of the present invention, the method further includes: introducing the C4 fraction and / or the light gasoline fraction into a third reactor to undergo a third catalytic conversion reaction with a second catalytic conversion catalyst to obtain a second oil-fuel mixture; The second oil mixture is introduced into the second reactor together with the first oil mixture for reaction; and the regenerated catalyst is divided into at least two streams and then introduced into the first reactor and the third reactor respectively.

[0048] In the above embodiments, the second catalytic conversion catalyst may be the same as or different from the first catalytic conversion catalyst, preferably the same. Specifically, the second catalytic conversion catalyst includes a molecular sieve mixture, a heat-resistant inorganic oxide, and clay. Based on the total weight of the second catalytic conversion catalyst, the second catalytic conversion catalyst contains 1-60% by weight of the molecular sieve mixture, 5-99% by weight of the heat-resistant inorganic oxide, and 0-70% by weight of the clay, and the sum of the weight contents of each component is 100%. Based on the total weight of the molecular sieve mixture, the molecular sieve mixture contains 80-100% by weight of the MPZ hierarchical porous molecular sieve.

[0049] In some embodiments of the present invention, the third reactor may be a riser reactor, a fluidized bed reactor, a downflow conveyor reactor, or a composite reactor composed of multiple such reactors connected in series and / or in parallel, wherein each reactor may be divided into two or more reaction zones as needed.

[0050] In some embodiments of the present invention, the third reactor is provided with a first reaction zone and a second reaction zone from bottom to top.

[0051] The C4 fraction is introduced into the first reaction zone for reaction; and / or the light gasoline fraction is introduced into the second reaction zone for reaction.

[0052] The first reaction zone is located in the lower part of the third reactor, and the second reaction zone is located in the upper middle part of the third reactor.

[0053] In some specific embodiments of the present invention, the C4 fraction is introduced into a first reaction zone for catalytic conversion. The reaction conditions in the first reaction zone may include: a reaction temperature of 620-680℃, preferably 630-680℃; a weight ratio of the second catalytic conversion catalyst to the C4 fraction of 20-80, preferably 30-70; an oil-gas residence time of 0.5-1.5s, preferably 0.5-1.0s; and a reaction pressure of 0.15-0.30MPa, preferably 0.15-0.20 MPa. In some specific embodiments of the present invention, the light gasoline fraction is introduced into the first reaction zone for catalytic conversion reaction. The reaction conditions in the second reaction zone include: a reaction temperature of 610-660℃, preferably 620-650℃; a weight ratio of the second catalytic conversion catalyst to the light gasoline fraction of 20-80, preferably 30-70; a residence time of 0.5-1.5s, preferably 0.5-1.0s; and a reaction pressure of 0.15-0.30MPa, preferably 0.15-0.20MPa.

[0054] The third reactor may also be injected with a diluent to reduce the partial pressure of the hydrocarbon feedstock. The weight ratio of the diluent to light hydrocarbons and heavy hydrocarbons is 0.01-0.5:1, preferably 0.05-0.4:1. The diluent is selected from one or a mixture of several of water vapor, low-carbon alkanes and nitrogen, preferably water vapor.

[0055] In a preferred embodiment of the present invention, the system for the above-described method for producing ethylene and propylene includes a first reactor 1, a second reactor 2, a third reactor 3, a settling tank 4, and a stripper 5, wherein the stripper 5 is located below the second reactor 2. Specifically, the first reactor 1 and the third reactor 3 are riser reactors, i.e., a first riser reactor and a second riser reactor, and the second reactor 2 is a fluidized bed reactor. The first reactor 1 and the third reactor 3 are connected to the fluidized bed reactor at any point.

[0056] Preferably, the stripper is coaxial with the fluidized bed reactor and located below it. The first and second riser reactors are both selected from at least one type of assembly consisting of circular tubes of equal diameter, frustoconical cylinders, or 1-6 straight cylinders of different diameters connected by a diameter-changing section; the fluidized bed reactor is selected from at least one type of assembly consisting of cylinders of equal diameter, frustoconical cylinders, or 1-6 straight cylinders of different diameters connected by a diameter-changing section. The outlet of the fluidized bed reactor is connected to the inlet of the gas-solid separation equipment within the settler 4 via a conveying passage, the diameter of which is 25%-45% of the diameter of the fluidized bed reactor.

[0057] The following is in conjunction with the appendix Figure 1 The method provided by the present invention will be further described, but this does not limit the present invention.

[0058] Figure 1 This illustration schematically shows a particularly preferred embodiment of the invention, such as... Figure 1 As shown, although the schematic diagram is for simplification, it does not affect the understanding of the present invention by those skilled in the art.

[0059] The modified heavy oil obtained after separation and upgrading of heavy hydrocarbon oil is preheated to 180℃-340℃ and then introduced into the lower part of the first reactor 1 along with water vapor through pipeline 13. It contacts the first catalytic conversion catalyst from the first regeneration pipe 11, controlled by the first regeneration pipe control valve 12, to undergo a first catalytic conversion reaction, yielding a first oil-catalyst mixture. This first oil-catalyst mixture is then introduced into the second reactor 2 for a second catalytic conversion reaction. The reaction stream carrying a small amount of catalyst enters the first-stage cyclone separator 41 and the second-stage cyclone separator 42 located in the settling tank 4 through the first delivery pipe 21 at the outlet of the second reactor 2 for gas-solid separation. The first delivery pipe 21 is directly connected to the connecting pipelines at the inlets of the first-stage cyclone separator 41 and the second-stage cyclone separator 42 to rapidly separate the catalyst and the reaction oil-gas. The separated reaction oil-gas is sent to a downstream separation device via the reaction oil-gas pipeline 43 for further separation. The separated catalyst is returned to the stripper 5 of the second reactor 2 to remove the catalyst and its associated oil-gas. After stripping, the spent catalyst is fed into the regenerator 6 for regeneration via the spent catalyst delivery pipe 52 and the controlled delivery pipe valve 53, under the action of the stripping baffle 51. Air enters the regenerator 6 through the main air inlet 61 to burn off the coke loaded on the spent catalyst. The resulting regenerated catalyst is returned to the bottom of the first reactor 1 via pipeline 11. The flue gas generated during catalyst regeneration in the regenerator is sent to the flue gas treatment unit through the flue gas outlet 62. The reaction oil and gas are further separated by the separation unit to obtain dry gas, liquefied petroleum gas, C4 fraction, light gasoline fraction, stabilized gasoline, diesel, and slurry oil.

[0060] Figure 2 Another preferred embodiment of the invention is shown, which further includes... Figure 1The C4 fraction and light gasoline fraction from the products separated in the apparatus shown are introduced into the third reactor 3 for reprocessing. The C4 fraction from the separation apparatus of the present invention is introduced into the bottom of the third reactor 3 through pipeline 33, and the light gasoline fraction from the separation apparatus of the present invention is introduced into the middle of the third reactor 3 through pipeline 34, where it comes into contact with the hot second catalytic conversion catalyst from the second regeneration pipe 31, controlled by the second regeneration pipe control valve 32, to carry out the third catalytic conversion reaction. The oil-catalyst mixture obtained from the third reactor 3 is introduced into the second reactor 2 for further reaction. The reaction stream carrying a small amount of catalyst enters the cyclone separator rapidly through the connecting pipeline between the outlet of the second reactor 2 and the inlet of the cyclone separators 41 and 42. The separated reaction oil and gas enter the downstream separation unit, and the separated spent catalyst is returned to the bottom of the first reactor 1 and the third reactor 3.

[0061] The present invention will be further described in detail below through embodiments, but the invention is not limited thereto. All raw materials used in the embodiments are commercially available.

[0062] The catalytic conversion catalysts used in the examples and comparative examples were MPZ molecular sieve catalyst and Eplene-10 catalyst, both produced by Sinopec Catalyst Branch. Their composition and properties are shown in Table 1. Based on the total amount of MPZ molecular sieve catalyst, the MPZ catalyst contained 35 wt% MPZ molecular sieve (silicon-to-alumina ratio of 22), 40 wt% kaolin, and 25 wt% alumina binder. The Eplene-10 catalyst contained 35 wt% ZSM-5 molecular sieve (silicon-to-alumina ratio of 22). Both the MPZ molecular sieve catalyst and the Eplene-10 catalyst were aged at 800℃ under a 100% steam atmosphere for 17 h before use. After hydrothermal aging, in the NH3-TPD spectra, the proportions of the strong acid center peak area with a desorption temperature above 200℃ to the total acid center peak area were 55.7% and 42.9%, respectively.

[0063] The raw materials used in the examples and comparative examples are heavy hydrocarbon oil and modified heavy hydrocarbon oil, the composition and properties of which are shown in Table 2.

[0064] The examples and comparative examples are all in the appendix. Figure 1 and attached Figure 2 The experiment was conducted on the medium-sized experimental setup shown. The first reactor 1 is a riser reactor with an inner diameter of 18 mm and a height of 5 m; the second reactor 2 is a fluidized bed reactor with an inner diameter of 64 mm and a height of 0.4 m; the settler has an inner diameter of 300 mm; and the third reactor 3 is a riser reactor with an inner diameter of 12 mm and a height of 6 m.

[0065] Table 1. Composition and properties of catalytic conversion catalysts

[0066] Table 2 Composition and properties of heavy hydrocarbon oils and modified heavy hydrocarbon oils

[0067] Example 1 The experiment in this embodiment is... Figure 1 The process is carried out on a medium-sized unit. Modified heavy hydrocarbon oil is introduced into the first reactor, where it contacts the first catalytic conversion catalyst from the regenerator to undergo the first catalytic conversion reaction. The reactant gas and catalyst do not need to be separated and are introduced into the second reactor to continue the reaction, i.e., the second catalytic conversion reaction. The reactant stream carrying a small amount of catalyst enters the cyclone separator rapidly through a connecting pipeline between the outlet of the second reactor and the inlet of the cyclone separator. The separated catalyst is returned to the second reactor. The carbonized catalyst in the second reactor enters the stripper, where the catalyst-carried oil and gas are stripped off, and then sent to the regenerator for regeneration. The separated reactant gas enters the fractionation unit for further separation, yielding dry gas, liquefied petroleum gas (LPG), C4 fraction, light gasoline, stabilized gasoline, diesel, and slurry oil. The C4 fraction has a distillation range of -15°C to 15°C; the light gasoline has a distillation range of 15-60°C.

[0068] The reaction conditions and results are shown in Table 3.

[0069] Example 2-3 The methods for producing ethylene and propylene in Examples 2-3 are basically similar to the catalytic conversion method in Example 1, except that the reaction conditions in the first and second reactors are different. The reaction conditions and results are shown in Table 3.

[0070] Example 4 The method for producing ethylene and propylene in Example 4 is basically similar to the catalytic conversion method in Example 1, except that the reaction temperature in the first reactor is 680°C, and the reaction temperature in the second reactor is 602°C. The reaction conditions and results are shown in Table 3.

[0071] Comparative Example 1 The method for producing ethylene and propylene in Comparative Example 1 is basically similar to the catalytic conversion method in Example 1, except that the catalytic conversion catalyst is Eplene-10 catalyst. The reaction conditions and results are shown in Table 3.

[0072] Comparative Example 2 The method for producing ethylene and propylene in Comparative Example 2 is basically similar to the catalytic conversion method in Example 1, except that the feedstock introduced into the first reactor is unmodified heavy hydrocarbon oil (properties shown in Table 2), and the catalytic conversion catalyst is Eplene-10 catalyst. The reaction conditions and results are shown in Table 3.

[0073] Table 3. Reaction conditions and results of Examples 1-4 and Comparative Examples 1-2

[0074] As shown in Table 3, the apparatus and method provided by the present invention have enhanced different reactions, significantly improved the selectivity of the target product, and reduced the coking rate.

[0075] Comparing Example 1 and Comparative Example 2, it can be seen that the modified heavy hydrocarbon oil contains less heavy and asphaltenes, resulting in a significant reduction in coke production. However, with a lower conversion rate, the yields of ethylene and propylene are greatly improved.

[0076] Compared with Comparative Example 1, the method of the present invention uses a catalyst containing MPZ hierarchical porous molecular sieves to catalytically convert modified hydrocarbon oils, resulting in higher selectivity for ethylene and propylene.

[0077] In Example 5 and Comparative Example 3, the C4 fraction and light gasoline fraction produced by this device were also introduced into the third reactor. The composition and properties of the C4 fraction and light gasoline fraction are shown in Table 4 and Table 5, respectively.

[0078] Table 4 Composition of C4 fraction

[0079] Table 5. Group composition of light gasoline fractions

[0080] Example 5 The method for producing ethylene and propylene in Example 5 is basically similar to the catalytic conversion method in Example 1, except that it further includes introducing the C4 fraction and light gasoline fraction obtained from the separation of the reaction products into the third reactor from the bottom and upper middle parts, respectively, to contact the second catalytic conversion catalyst from the regenerator for the third catalytic conversion reaction. The reaction conditions and reaction results are shown in Table 6.

[0081] Comparative Example 3 The method for producing ethylene and propylene in Comparative Example 3 is basically similar to the catalytic conversion method in Comparative Example 2, except that it also includes introducing the C4 fraction and light gasoline fraction obtained from the separation of the reaction products into the third reactor from the bottom and upper middle parts, respectively, to contact the second catalytic conversion catalyst from the regenerator for the third catalytic conversion reaction. The reaction conditions and results are shown in Table 6.

[0082] Table 6. Reaction conditions and results of Example 5 and Comparative Example 3

[0083] As shown in Table 6, by refining the C4 fraction and light gasoline, the selectivity of ethylene and propylene in the method provided by the present invention is further improved.

[0084] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of 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.

[0085] 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.

[0086] 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 from heavy hydrocarbon oil, characterized in that, The method includes: The modified heavy oil is introduced into the first reactor and contacted with the first catalytic conversion catalyst to carry out the first catalytic conversion reaction, thereby obtaining the first oil-catalyst mixture. The first oil-agent mixture is introduced into the second reactor to carry out the second catalytic conversion reaction. The reaction stream is then subjected to gas-solid separation to obtain the reaction oil-gas and the catalyst to be generated. The reaction oil and gas are separated to obtain ethylene, propylene, C4 fraction and light gasoline fraction products; The spent catalyst is regenerated by coking to obtain a regenerated catalyst, and part or all of the regenerated catalyst is recycled back to the first reactor. The modified heavy oil contains asphaltene at a content of 0.01-0.2% by weight; the first catalytic conversion catalyst comprises MPZ multi-level porous molecular sieve.

2. The catalytic conversion method according to claim 1, wherein, The modified heavy oil satisfies at least one of the following conditions: i. Asphalt content is 0.01-0.1% by weight; ii. The gum content is 0.5-12.0% by weight, preferably 1-10.0% by weight; iii. The residual char content is 0.2-2.0% by weight; iv. Total metal content is less than 1.0 ppm.

3. The catalytic conversion method according to claim 1, wherein, The method further includes: contacting heavy hydrocarbon oil with an organic solvent to perform deasphalting treatment, thereby obtaining the modified heavy oil and deoiled asphalt; The conditions for the deasphalting treatment include: a reaction temperature of 10-200 ℃, preferably 20-180 ℃; a reaction pressure of 1.0-15.0 MPa, preferably 2.0-13.0 MPa; and a weight ratio of organic solvent to heavy hydrocarbon oil of 1-20, preferably 3-10. The organic solvent is selected from one or more of C3-C6 alkanes, preferably at least one of propane, n-butane and n-pentane; Optionally, the content of gum in the heavy hydrocarbon oil is 5.0-20.0% by weight, and the content of asphaltene is 0.5-5.0% by weight; the heavy hydrocarbon oil is selected from one or a mixture of several of vacuum gas oil, atmospheric residue, vacuum residue, hydrotreated vacuum gas oil, and hydrotreated atmospheric residue.

4. The catalytic conversion method according to claim 1, wherein, The first catalytic conversion catalyst comprises a molecular sieve mixture, a heat-resistant inorganic oxide, and clay. Based on the total weight of the first catalytic conversion catalyst, the first catalytic conversion catalyst contains 1-60% by weight of the molecular sieve mixture, 5-99% by weight of the heat-resistant inorganic oxide, and 0-70% by weight of the clay, and the sum of the weight contents of each component is 100%. Based on the total weight of the molecular sieve mixture, the molecular sieve mixture contains 80-100% by weight of the MPZ multi-level porous molecular sieve.

5. The catalytic conversion method according to claim 1, wherein, In the surface XPS elemental analysis of the MPZ multi-level porous molecular sieve, n1 / n2 is less than or equal to 0.08, where n1 represents the number of moles of phosphorus in the MPZ multi-level porous molecular sieve, and n2 represents the total number of moles of silicon and aluminum in the MPZ multi-level porous molecular sieve.

6. The catalytic conversion method according to claim 1, wherein, After hydrothermal aging at 800℃ and 100% steam for 17 hours, the NH3-TPD spectrum of MPZ hierarchical porous molecular sieve shows that the area of ​​strong acid center peaks with desorption temperatures above 200℃ accounts for more than 45% of the total acid center peak area.

7. The catalytic conversion method according to claim 1, wherein, The conditions for the first catalytic conversion reaction include: a reaction temperature of 550-680℃, preferably 570-660℃; a weight ratio of the first catalytic conversion catalyst to the modified heavy oil of 8-40, preferably 10-30; an oil-gas residence time of 0.5-6 s, preferably 0.8-5 s; and a reaction pressure of 0.15-0.30 MPa, preferably 0.17-0.25 MPa. Optionally, the first reactor is selected from a riser reactor, a fluidized bed reactor, a downflow conveyor reactor, or a composite reactor composed of multiple such reactors connected in series and / or in parallel, preferably a riser reactor.

8. The catalytic conversion method according to claim 1, wherein, The reaction conditions for the second catalytic conversion include: a reaction temperature of 570-650 °C, preferably 575-645 °C; and a weight hourly space velocity of 1-30 h⁻¹. -1 Preferably 3-20 h -1 The reaction pressure is 0.15-0.30 MPa, preferably 0.15-0.20 MPa; Optionally, the second reactor is selected from one or more of the following: a dispersed fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, and a dense phase fluidized bed reactor.

9. The catalytic conversion method according to claim 1, wherein, The method further includes: introducing the C4 fraction and / or the light gasoline fraction into a third reactor to carry out a third catalytic conversion reaction with a second catalytic conversion catalyst to obtain a second oil-fuel mixture; The second oil mixture is introduced into the second reactor along with the first oil mixture for reaction; and the regenerated catalyst is divided into at least two streams and then introduced into the first reactor and the third reactor respectively; Optionally, the second catalytic conversion catalyst comprises a molecular sieve mixture, a heat-resistant inorganic oxide, and clay. Based on the total weight of the second catalytic conversion catalyst, the second catalytic conversion catalyst contains 1-60% by weight of the molecular sieve mixture, 5-99% by weight of the heat-resistant inorganic oxide, and 0-70% by weight of the clay, and the sum of the weight contents of each component is 100%. Based on the total weight of the molecular sieve mixture, the molecular sieve mixture contains 80-100% by weight of the MPZ hierarchical porous molecular sieve.

10. The catalytic conversion method according to claim 9, wherein, The third reactor is provided with a first reaction zone and a second reaction zone from bottom to top; The C4 fraction is introduced into the first reaction zone for reaction; and / or The light gasoline fraction is introduced into the second reaction zone for reaction; The reaction conditions in the first reaction zone include: a reaction temperature of 620-680℃, preferably 630-680℃; a weight ratio of the second catalytic conversion catalyst to the C4 fraction of 20-80, preferably 30-70; an oil-gas residence time of 0.5-1.5s, preferably 0.5-1.0s; a reaction pressure of 0.15-0.30MPa, preferably 0.15-0.20 MPa; and / or The reaction conditions in the second reaction zone include: a reaction temperature of 610-660℃, preferably 620-650℃; a weight ratio of the second catalytic conversion catalyst to light gasoline fraction of 20-80, preferably 30-70; an oil-gas residence time of 0.5-1.5s, preferably 0.5-1.0s; and a reaction pressure of 0.15-0.30MPa, preferably 0.15-0.20 MPa. Optionally, the third reactor is selected from a riser reactor, a fluidized bed reactor, a downflow conveyor reactor, or a composite reactor composed of multiple such reactors connected in series and / or in parallel, preferably a riser reactor.

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