Catalytic conversion method for producing ethylene and propylene from hydrocarbons

Abstract

The invention relates to a catalytic conversion method for producing ethylene and propylene from hydrocarbons, which comprises the following steps: contacting a heavy hydrocarbon raw material with a regenerated catalyst in a first reactor to carry out a first catalytic conversion reaction, and carrying out first separation on the material after the first catalytic conversion reaction to obtain a first spent catalyst and first reaction oil gas; and contacting the light hydrocarbon raw material with a fresh catalyst in a second reactor to carry out a second catalytic conversion reaction, and carrying out second separation on the material after the second catalytic conversion reaction to obtain a second spent catalyst and second reaction oil gas. The fresh catalyst and the light hydrocarbon raw material are contacted for reaction, the heavy hydrocarbon raw material and the regenerated catalyst are contacted for reaction, the high acid density and strong acid center of the fresh catalyst are fully utilized, and the light hydrocarbon raw material rich in olefin can be converted into ethylene and propylene with high selectivity.

Description

Technical Field

[0001] The present invention belongs to the field of petroleum processing, and in particular relates to a catalytic conversion method for producing ethylene and propylene from hydrocarbons. Background Art

[0002] Ethylene and propylene are important basic chemical raw materials, and their downstream products are widely used in fields such as building materials, electronics, medical devices, and the automotive industry. They play an irreplaceable role in production and daily life. Currently, the main sources of ethylene are steam cracking and catalytic cracking of hydrocarbon oils, while propylene is mainly produced through naphtha cracking. Catalytic cracking is a key secondary crude oil processing technology, characterized by wide feedstock adaptability, high heavy oil conversion rates, and flexible product options. It is a key method for producing light olefins such as ethylene, propylene, and butenes. Typical heavy oil catalytic conversion processes to produce light olefins include the DCC process, CPP process, Maxofin process, and PetroFCC process. These processes convert heavy hydrocarbons at reaction temperatures of 500-600°C, while recycling intermediate C4 components and light hydrocarbons such as pyrolysis gasoline in a secondary reactor. Further cracking is performed at higher reaction temperatures than those used for heavy hydrocarbon conversion to increase light olefin production.

[0003] CN102690682A discloses a catalytic cracking method for producing propylene. The method involves contacting a heavy feedstock with a first catalytic cracking catalyst containing Y-type zeolite as the primary active component in a first riser reactor for a first reaction. Light hydrocarbons are then contacted with a second catalytic cracking catalyst containing a shape-selective zeolite with a pore size of less than 0.7 nm as the primary active component in a second riser reactor for a second reaction. The oil, gas, and catalyst after the second reaction are introduced into a fluidized bed reactor connected in series with the second riser reactor for reaction. Two independent stripping zones are provided: one stripping zone cooperates with the first riser reactor to form one reaction and stripping route, and the other stripping zone cooperates with the second riser reactor and the fluidized bed reactor to form another reaction and stripping route.

[0004] CN1189434C discloses a method for producing propylene by catalytic cracking of C4 or higher olefins. The method comprises partially covering the strong acid centers of the molecular sieve and reducing the effective pore size of the molecular sieve by treating the ZSM zeolite with alkaline earth metals to inhibit hydrogen transfer reactions and thereby retain as many olefins as possible. The method also improves the selectivity of the molecular sieve for propylene, resulting in a high propylene yield.

[0005] CN102337148A discloses a C4-rich ＝ ~C8 ＝ The invention relates to a method for producing propylene by catalytic conversion of olefin raw materials, wherein the raw materials are contacted with SAPO molecular sieve and / or high-silicon molecular sieve with a five-membered ring structure in a fluidized bed for reaction, thereby producing light olefins with high selectivity.

[0006] CN109678634A discloses a method for increasing the production of ethylene and propylene. In this method, C5-C9 hydrocarbons having an olefin content of 3-10 wt% are contacted with a mixture of regenerated catalyst and fresh catalyst for a catalytic cracking reaction. The fresh catalyst is used to increase the yield of ethylene and propylene in the catalytic cracking products of the difficult-to-crack C5-C9 hydrocarbons. However, when catalytic cracking is performed using heavy hydrocarbons and olefin-rich light hydrocarbons as feedstocks, the yield of ethylene and propylene needs to be further increased. Summary of the Invention

[0007] The object of the present invention is to further increase the yield of ethylene and propylene in a process for the catalytic conversion of heavy hydrocarbons and olefin-rich light hydrocarbons.

[0008] In order to achieve the above-mentioned objectives, the present invention provides a catalytic conversion method for producing ethylene and propylene from hydrocarbons, which method comprises the following steps: contacting a heavy hydrocarbon feedstock with a regenerated catalyst in a first reactor to perform a first catalytic conversion reaction, and performing a first separation on the material after the first catalytic conversion reaction to obtain a first regenerated catalyst and a first reaction oil and gas; contacting a light hydrocarbon feedstock with a fresh catalyst in a second reactor to perform a second catalytic conversion reaction, and performing a second separation on the material after the second catalytic conversion reaction to obtain a second regenerated catalyst and a second reaction oil and gas.

[0009] Optionally, the method further comprises: discharging part of the carbon deposited catalyst through a carbon deposited catalyst outlet pipe provided at the lower portion of the second reactor; preferably, the second reactor is a fluidized bed or an ebullating bed.

[0010] Optionally, the mass ratio of the fresh catalyst to the heavy hydrocarbon feedstock is (0.0001-0.1):1, preferably (0.0005-0.005):1.

[0011] Optionally, the conditions for the first catalytic conversion reaction include: a temperature of 450-700°C, preferably 520-650°C; a pressure of 0.1-0.2 MPa, preferably 0.1-0.15 MPa; a mass ratio of the heavy hydrocarbon feedstock to the regenerated catalyst of 1:(3-100), preferably 1:(8-40); a mass ratio of the heavy hydrocarbon feedstock to water vapor of 1:(0.05-5), preferably 1:(0.2-2); an oil and gas residence time of 0.1-100 seconds, preferably 0.5-20 seconds; and / or the conditions for the second catalytic conversion reaction include: a temperature of 500-750°C, preferably 550-700°C; a pressure of 0.1-0.2 MPa, preferably 0.1-0.15 MPa; a weight hourly space velocity of 0.1-50 h -1 , preferably 0.2 to 10 hours -1 The weight ratio of the light hydrocarbon raw material to water vapor is 1: (0.1 to 5), preferably 1: (0.2 to 3).

[0012] Optionally, the active components of the fresh catalyst include ZSM series zeolite and Y series zeolite; wherein the mass ratio of the ZSM series zeolite to the Y series zeolite is (1-20):1, preferably (2-10):1.

[0013] Optionally, the Y series zeolite is selected from at least one of Y or HY type zeolites containing or not containing rare earths, and ultrastable Y type zeolites containing or not containing rare earths; the ZSM series zeolite is selected from at least one of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and ZSP.

[0014] Optionally, the method further includes: separating light hydrocarbons from the first reaction oil gas and / or the second reaction oil gas and using the light hydrocarbon feedstock as a light hydrocarbon feedstock to participate in the second catalytic conversion reaction.

[0015] Optionally, the micro-reaction activity of the regenerated catalyst is 40-80%, preferably 50-70%; and / or the micro-reaction activity of the fresh catalyst is 70-95%, preferably 75-85%.

[0016] Optionally, the first reactor is selected from one or more of a riser, a fluidized bed, a fast bed and a downcomer; and / or the second reactor is selected from one or more of a diameter fluidized bed, a constant linear velocity fluidized bed and a variable diameter fluidized bed.

[0017] Optionally, the heavy hydrocarbon feedstock is selected from one or more of petroleum hydrocarbons, mineral oils, synthetic oils, animal fats and vegetable oils; the light hydrocarbon feedstock is selected from one or more of C4 to C10 hydrocarbons; wherein the petroleum hydrocarbons are selected from one or more of crude oil, atmospheric wax oil, vacuum wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, hydrogenated heavy oil, coker wax oil, diesel and naphtha; the mineral oil is selected from one or more of coal liquefaction oil, oil sands oil and shale oil.

[0018] Through the above technical scheme, the present invention makes full use of the high acid density and strong acid center of the fresh catalyst by contacting the fresh catalyst with the light hydrocarbon feedstock to react, and makes the heavy hydrocarbon feedstock contact with the regenerated catalyst to react, and converts the olefin-rich light hydrocarbon feedstock into ethylene and propylene with high selectivity.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 The present invention provides a catalytic conversion process flow chart for producing ethylene and propylene from hydrocarbons.

[0022] Description of reference numerals:

[0023] 1. Riser reactor; 11. Heavy hydrocarbon feed nozzle; 2. Fluidized bed reactor; 3. Second reactor; 31. Light hydrocarbon feed line; 32. Feed distributor; 33. Fresh catalyst delivery pipe; 34. Carbon deposited catalyst output pipe; 4. Settler; 41. Cyclone separator; 42. Oil and gas output pipe; 5. Stripper; 51. Stripping steam delivery pipe; 52. Regenerated catalyst delivery pipe; 6. Regenerator; 61. Air delivery pipe; 62. Regenerated flue gas delivery pipe; 63. Regenerated catalyst delivery pipe. DETAILED DESCRIPTION

[0024] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0025] The present invention provides a catalytic conversion method for producing ethylene and propylene from hydrocarbons, the method comprising the following steps:

[0026] The heavy hydrocarbon feedstock is brought into contact with the regenerated catalyst in the first reactor to carry out a first catalytic conversion reaction, and the material after the first catalytic conversion reaction is subjected to a first separation to obtain a first catalyst to be regenerated and a first reaction oil and gas; the light hydrocarbon feedstock is brought into contact with the fresh catalyst in the second reactor to carry out a second catalytic conversion reaction, and the material after the second catalytic conversion reaction is subjected to a second separation to obtain a second catalyst to be regenerated and a second reaction oil and gas.

[0027] The present invention allows a fresh catalyst to contact a light hydrocarbon feedstock for reaction, and allows a heavy hydrocarbon feedstock to contact a regenerated catalyst for reaction, thereby fully utilizing the high acid density and strong acid center of the fresh catalyst to convert the olefin-rich light hydrocarbon feedstock into ethylene and propylene with high selectivity.

[0028] In some embodiments of the present invention, the method further comprises: introducing the first spent catalyst into a regenerator for regeneration to obtain the regenerated catalyst; and introducing the second spent catalyst into a stripper for stripping, then into the regenerator for regeneration, and returning it to the first reactor for recycling as part of the regenerated catalyst. Directly introducing the second separated carbonized catalyst into the stripper for stripping and regeneration before returning it to the first reactor satisfies the catalyst activity requirements for catalytic cracking of heavy hydrocarbons and is beneficial for improving the yields of ethylene and propylene. Alternatively, the first spent catalyst and the second spent catalyst can be regenerated in different regenerators and then introduced into the first reactor in a specific ratio.

[0029] In some embodiments of the present invention, the method further includes: discharging a portion of the coked catalyst through a coked catalyst outlet pipe located at the bottom of the second reactor; and controlling the ratio of coked catalyst to regenerated catalyst entering the first reactor, thereby reducing production costs while meeting the catalyst activity requirements for the catalytic conversion of heavy hydrocarbons. Specifically, the coked catalyst outlet pipe is located at the bottom of the second reactor. For example, if the second reactor is a fluidized bed reactor, the coked catalyst outlet pipe can be located above a material distributor on the fluidized bed reactor.

[0030] In some preferred embodiments of the present invention, the second reactor is a fluidized bed or an ebullating bed. Further preferably, the second reactor is selected from one or more of a diameter fluidized bed, a constant linear velocity fluidized bed, and a variable diameter fluidized bed.

[0031] In some embodiments of the present invention, the first reactor is selected from one or more of a riser, a fluidized bed, a fast bed and a downer.

[0032] In some embodiments of the present invention, the mass ratio of the fresh catalyst to the heavy hydrocarbon feedstock is (0.0001-0.1):1. By controlling the mass ratio of the introduced fresh catalyst to the heavy hydrocarbon feedstock, the yield of ethylene and propylene in the catalytic conversion products of the light hydrocarbon feedstock can be increased. At the same time, the activity of the regenerated catalyst can be fully utilized to meet the catalyst activity requirements of the catalytic cracking of the heavy hydrocarbon feedstock, thereby increasing the production of ethylene and propylene. In some preferred embodiments of the present invention, the mass ratio of the fresh catalyst to the heavy hydrocarbon feedstock is (0.0005-0.005):1.

[0033] In some embodiments of the present invention, the conditions of the first catalytic conversion reaction include: a temperature of 450 to 700°C, preferably 520 to 650°C; a pressure of 0.1 to 0.2 MPa, preferably 0.1 to 0.15 MPa; a mass ratio of the heavy hydrocarbon feedstock to the regenerated catalyst of 1:(3 to 100), preferably 1:(8 to 40); a mass ratio of the heavy hydrocarbon feedstock to water vapor of 1:(0.05 to 5), preferably 1:(0.2 to 2); and an oil and gas residence time of 0.1 to 100 seconds, preferably 0.5 to 20 seconds.

[0034] In some embodiments of the present invention, the conditions for the second catalytic conversion reaction include: a temperature of 500-750°C, preferably 550-700°C; a pressure of 0.1-0.2 MPa, preferably 0.1-0.15 MPa; a weight hourly space velocity of 0.1-50 h -1 , preferably 0.2 to 10 hours -1 The weight ratio of the light hydrocarbon raw material to water vapor is 1: (0.1 to 5), preferably 1: (0.2 to 3).

[0035] In some embodiments of the present invention, the active components of the fresh catalyst include ZSM series zeolite and Y series zeolite; specifically, in order to meet the requirements of heavy hydrocarbon feedstock and light hydrocarbon feedstock for different active components, the mass ratio of the ZSM series zeolite to the Y series zeolite is (1-20):1, preferably (2-10):1.

[0036] In the present invention, the mass ratio of ZSM series zeolite to Y series zeolite in the fresh catalyst and the regenerated catalyst can be consistent. The fresh catalyst and the regenerated catalyst mainly contain shape-selective ZSM zeolite and a small amount of Y-type zeolite, so as to simultaneously meet the catalyst requirements of heavy hydrocarbon feedstocks and light hydrocarbon feedstocks.

[0037] In some specific embodiments of the present invention, the Y series zeolite is selected from at least one of Y or HY type zeolites containing or not containing rare earth, and ultrastable Y type zeolites containing or not containing rare earth.

[0038] In some specific embodiments of the present invention, the ZSM series zeolite is selected from at least one of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and ZSP.

[0039] ZSM zeolite is a shape-selective catalyst that can selectively crack gasoline and other components in the products of heavy hydrocarbon catalytic conversion into olefins below C5. The larger pore size of the Y-type zeolite in fresh and regenerated catalysts allows heavy hydrocarbon molecules to adsorb on the Y-type zeolite, allowing the catalytic conversion reaction to proceed. This provides feedstock for the ZSM zeolite's catalytic conversion, thereby increasing the yield of ethylene and propylene in the products.

[0040] In some embodiments of the present invention, the method further includes separating light hydrocarbons from the first reaction oil gas and / or the second reaction oil gas, and using these as light hydrocarbon feedstocks for the second catalytic conversion reaction. The separated light hydrocarbons are recycled to increase the yield of high-value-added ethylene and propylene.

[0041] In some embodiments of the present invention, the micro-reaction activity of the regenerated catalyst is 40 to 80%, preferably 50 to 70%.

[0042] In some embodiments of the present invention, the micro-reaction activity of the fresh catalyst is 70-95%, preferably 75-85%. The micro-reaction activity is determined using the RIPP 92-90 Micro-reaction Activity Test for Catalytic Cracking Industrial Equilibrium Catalysts (Analytical Methods in Petrochemical Industry (RIPP Test Method), edited by Yang Cuiding et al., 1990 edition). A fresh catalyst refers to a commercially available or prepared unused catalyst.

[0043] In some embodiments of the present invention, the heavy hydrocarbon feedstock is selected from one or more of petroleum hydrocarbons, mineral oils, synthetic oils, animal fats and vegetable oils; wherein the petroleum hydrocarbons are selected from one or more of crude oil, atmospheric wax oil, vacuum wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, hydrogenated heavy oil, coker wax oil, diesel and naphtha; and the mineral oil is selected from one or more of coal liquefaction oil, oil sands oil and shale oil.

[0044] In some embodiments of the present invention, the light hydrocarbon feedstock is selected from one or more C4-C10 hydrocarbons. The light hydrocarbon feedstock can be selected from C4-C10 hydrocarbons as needed. For example, the light hydrocarbons can be part or all of the C4-C10 hydrocarbon fractions. Specifically, the light hydrocarbons are sourced from a catalytic cracking unit, a coking unit, a reforming unit, an aromatics extraction unit, or an atmospheric column.

[0045] In some preferred embodiments of the present invention, the light hydrocarbon feedstock is selected from one or more of C4-C10 paraffins, C4-C10 olefins and C4-C10 cycloalkanes.

[0046] The C4-C10 alkane is one of the alkanes with a carbon number of 4 to 10, such as n-butane, n-pentane or n-hexane, or a mixture of alkanes with the same carbon number but different molecular structures, or a mixture of alkanes with several carbon numbers.

[0047] The C4 to C10 olefin is one of the olefins with a carbon number of 4 to 10, such as 1-butene, 1-pentene, 2-pentene or 1-hexene, or a mixture of olefins with the same carbon number but different molecular structures, such as 1-pentene, cis-2-pentene, trans-2-pentene, 2-methyl-1-butene, 2-methyl-2-butene and 3-methyl-1-butene, or a mixture of olefins with several carbon numbers.

[0048] Among them, C4~C10 cycloalkane is one of the cycloalkanes with a carbon number of 4 to 10, such as cyclobutane, cyclopentane or cyclohexane, and can also be a mixture of cycloalkanes with the same carbon number but different molecular structures, or a mixture of cycloalkanes with several carbon numbers.

[0049] Specific embodiments of the present invention are provided below in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0050] Figure 1 A flow chart showing a method for catalytic conversion of hydrocarbons to produce ethylene and propylene according to the present invention is shown in FIG. Figure 1 The first reactor includes a riser reactor 1 and a fluidized bed reactor 2 coaxially arranged with the riser reactor 1. The second reactor is a fluidized bed reactor 3 arranged in parallel with the riser reactor 1.

[0051] The regenerated catalyst is introduced into the bottom of the riser reactor 1 through the regenerated catalyst delivery pipe 63 and flows upward under the action of the pre-lift medium. The heavy hydrocarbon feedstock and water vapor are sprayed into the riser reactor 1 through the heavy hydrocarbon feed nozzle 11 to contact the regenerated catalyst for a catalytic cracking reaction. Then the oil agent moves upward to continue the catalytic cracking reaction in the fluidized bed reactor 2. The first oil agent after the reaction undergoes heavy hydrocarbon gas-solid separation in the settler 4 to separate the first regenerated catalyst and the first reaction oil gas. The first regenerated catalyst enters the stripper 5, and after the adsorbed hydrocarbon products are stripped, it is sent to the regenerator 6 through the regenerated catalyst delivery pipe 52 for regeneration. The regenerated catalyst returns to the riser reactor 1 for recycling.

[0052] Fresh catalyst is added to the second reactor 3 via the fresh catalyst delivery pipe 33. The light hydrocarbon feedstock and water vapor enter the second reactor 3 via the light hydrocarbon feed line 31, where they contact the fresh catalyst for a catalytic cracking reaction, producing a second reaction mass. The second reaction mass undergoes light hydrocarbon gas-solid separation in the settler 4, producing a second regenerated catalyst and a second reaction oil and gas. The first reaction oil and gas enter the product separation system. Light hydrocarbon gas-solid separation occurs in the cyclone separator 41, and the cyclone's feed leg extends to the stripper 5. The solid material obtained from the light hydrocarbon gas-solid separation enters the stripper 5 for stripping and is then regenerated in the regenerator 6. It is then delivered to the bottom of the riser reactor 1 as regenerated catalyst.

[0053] Alternatively, in other embodiments, the second spent catalyst is directly fed into the regenerator 6 for regeneration.

[0054] The method provided by the present invention is further described in detail below by way of examples, but the present invention is not limited thereto.

[0055] The heavy hydrocarbon used in the examples of the present invention and the comparative examples is atmospheric residue oil, and the light hydrocarbon is light gasoline. The properties of the atmospheric residue oil are shown in Table 1, and the composition (weight %) of the light gasoline is shown in Table 2.

[0056] Table 1

[0057]

[0058] Table 2

[0059]

[0060]

[0061] The properties of the catalysts used in the examples of the present invention and the comparative examples are shown in Table 3.

[0062] Table 3

[0063]

[0064] Example 1

[0065] According to the attached Figure 1 The medium-scale unit in the process flowsheet shown was tested. The heavy hydrocarbon feedstock used atmospheric residue (properties shown in Table 1) and the light hydrocarbon feedstock used light gasoline (composition shown in Table 2). The mass ratio of atmospheric residue to light gasoline was 20:3. The catalytic conversion reaction of the heavy hydrocarbon feedstock was carried out in the first reactor, a combined riser and fluidized bed reactor. The second reactor, used for the reaction of the light hydrocarbon feedstock, was a fluidized bed reactor.

[0066] During the experiment, atmospheric residue and steam were injected into the riser reactor through a heavy hydrocarbon feed nozzle, where they contacted the regenerated catalyst for a catalytic cracking reaction. The oil then ascended to continue the catalytic cracking reaction in the fluidized bed reactor. The reacted first oil was subjected to heavy hydrocarbon gas-solid separation in a settler, yielding the first spent catalyst and the first reaction oil gas. The first spent catalyst then entered a stripper, where it was stripped of adsorbed hydrocarbon products and then transported via a spent catalyst transfer line to a regenerator for regeneration. The regenerated catalyst was then returned to the riser reactor for recycling. Fresh catalyst was added to the second reactor through the fresh catalyst transfer line. Light hydrocarbon feedstock and steam were then introduced into the second reactor through a light hydrocarbon feed line, where they contacted the fresh catalyst for a catalytic cracking reaction, yielding the second reaction mass. The second reaction mass then underwent light hydrocarbon gas-solid separation in the settler, yielding the second spent catalyst and the second reaction oil gas. The first and second reaction oil gases then entered the product separation system. Light hydrocarbon gas-solid separation was performed in a cyclone separator, and the solid material obtained from this separation was introduced into the stripping section of the first reactor. The medium-sized unit uses electric heating to maintain the temperature of the reaction and regeneration systems. The main operating conditions and results are shown in Table 4.

[0067] Example 2

[0068] This example used the same apparatus, raw materials, catalyst, and experimental procedures as in Example 1, except that the reaction temperature of the second reactor was 550° C. The main operating conditions and results are shown in Table 4.

[0069] Comparative Example 1

[0070] This comparative example employed the same reaction apparatus as in Example 1, along with the same raw materials, catalyst, and major steps as in Example 1. The difference from Example 1 was that fresh catalyst was added directly to the regenerator, and the catalytic conversion reaction of the light gasoline was carried out in contact with the regenerated catalyst. The main operating conditions and results are listed in Table 4.

[0071] Table 4

[0072]

[0073]

[0074] As can be seen from the data in Table 4, the catalytic conversion method for producing ethylene and propylene from hydrocarbons provided by the present invention can meet the catalytic conversion requirements of heavy hydrocarbon feedstocks and light hydrocarbon feedstocks, and significantly improve the yields of ethylene and propylene.

[0075] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0076] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0077] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A catalytic conversion method for producing ethylene and propylene from hydrocarbons, characterized in that: The method comprises the following steps: The heavy hydrocarbon feedstock is brought into contact with the regenerated catalyst in a first reactor to perform a first catalytic conversion reaction, and the material after the first catalytic conversion reaction is subjected to a first separation to obtain a first spent catalyst and a first reaction oil gas; The light hydrocarbon feedstock is brought into contact with the fresh catalyst in the second reactor to carry out a second catalytic conversion reaction, and the material after the second catalytic conversion reaction is subjected to a second separation to obtain a second spent catalyst and a second reaction oil and gas.

2. The method according to claim 1, wherein The method further includes: discharging a portion of the carbon deposited catalyst through a carbon deposited catalyst outlet pipe provided at a lower portion of the second reactor; Preferably, the second reactor is a fluidized bed or an ebullating bed.

3. The method according to claim 1, wherein The mass ratio of the fresh catalyst to the heavy hydrocarbon feedstock is (0.0001-0.1):1, preferably (0.0005-0.005):

1.

4. The method according to claim 1, wherein The conditions of the first catalytic conversion reaction include: a temperature of 450 to 700° C., preferably 520 to 650° C.; a pressure of 0.1 to 0.2 MPa, preferably 0.1 to 0.15 MPa; a mass ratio of the heavy hydrocarbon feedstock to the regenerated catalyst of 1:(3 to 100), preferably 1:(8 to 40); a mass ratio of the heavy hydrocarbon feedstock to water vapor of 1:(0.05 to 5), preferably 1:(0.2 to 2); an oil and gas residence time of 0.1 to 100 seconds, preferably 0.5 to 20 seconds; and / or The conditions of the second catalytic conversion reaction include: temperature of 500-750°C, preferably 550-700°C; pressure of 0.1-0.2 MPa, preferably 0.1-0.15 MPa; weight hourly space velocity of 0.1-50 h -1 , preferably 0.2 to 10 hours -1 The weight ratio of the light hydrocarbon raw material to water vapor is 1: (0.1 to 5), preferably 1: (0.2 to 3).

5. The method according to claim 1, wherein The active components of the fresh catalyst include ZSM series zeolite and Y series zeolite; The mass ratio of the ZSM series zeolite to the Y series zeolite is (1-20):1, preferably (2-10):

1.

6. The method according to claim 5, wherein: The Y series zeolite is selected from at least one of Y or HY type zeolites containing or not containing rare earth, and ultrastable Y type zeolites containing or not containing rare earth; the ZSM series zeolite is selected from at least one of ZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35, ZSM-38, ZSM-48 and ZSP.

7. The method according to claim 1, wherein The method further includes: separating light hydrocarbons from the first reaction oil gas and / or the second reaction oil gas, and using the light hydrocarbon raw materials as light hydrocarbon feedstocks to participate in the second catalytic conversion reaction.

8. The method according to claim 1, wherein The micro-reaction activity of the regenerated catalyst is 40-80%, preferably 50-70%; and / or The micro-reaction activity of the fresh catalyst is 70-95%, preferably 75-85%.

9. The method according to claim 1, wherein The first reactor is selected from one or more of a riser, a fluidized bed, a fast bed and a downer; and / or The second reactor is selected from one or more of a diameter fluidized bed, a constant linear velocity fluidized bed and a variable diameter fluidized bed.

10. The method according to claim 1, wherein The heavy hydrocarbon raw material is selected from one or more of petroleum hydrocarbons, mineral oils, synthetic oils, animal fats and vegetable fats; The light hydrocarbon raw material is selected from one or more of C4 to C10 hydrocarbons; The petroleum hydrocarbon is selected from one or more of crude oil, atmospheric wax oil, vacuum wax oil, atmospheric residue oil, vacuum residue oil, deasphalted oil, hydrogenated heavy oil, coker wax oil, diesel and naphtha; and the mineral oil is selected from one or more of coal liquefaction oil, oil sand oil and shale oil.

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