Device and method for preparing olefin through combination of petroleum hydrocarbon catalytic cracking and methanol-to-olefin

Abstract

The invention provides a device and a method for preparing olefin through combination of petroleum hydrocarbon catalytic cracking and methanol-to-olefin preparation. According to the device for preparing olefin through combination of petroleum hydrocarbon catalytic cracking and methanol-to-olefin provided by the invention, on the basis of an existing catalytic cracking device, a methanol-to-olefin unit is additionally arranged, so that a petroleum hydrocarbon catalytic cracking reaction and a methanol-to-olefin reaction are simultaneously carried out in the same set of device; the equipment cost for independently constructing a methanol-to-olefin device is reduced; reaction conditions in the petroleum hydrocarbon catalytic cracking unit and the methanol-to-olefin unit can be independently controlled, so that competition during simultaneous reaction of petroleum hydrocarbons and methanol is avoided; and the density of the catalyst in the methanol-to-olefin unit can be flexibly adjusted, so that the methanol feeding ratio of a catalytic cracking device is greatly improved, the methanol-to-olefin reaction is performed to the maximum extent, and the contents of ethylene and propylene in a catalytic cracking gas product are increased.

Description

An apparatus and method for the combined production of olefins from petroleum hydrocarbon catalytic cracking and methanol-to-olefins. Technical Field

[0001] This invention relates to the field of catalytic cracking, and specifically to an apparatus and method for the combined preparation of olefins from petroleum hydrocarbon catalytic cracking and methanol-to-olefins. Background Technology

[0002] Low-carbon olefins are a group of small-molecule olefins such as ethylene, propylene, and butene, and play a crucial role in the modern petroleum and chemical industry.

[0003] There are various methods for producing low-carbon olefins, most of which use petroleum hydrocarbons as raw materials and employ steam cracking processes. However, with the continuous rise in oil prices, the supply of raw materials for low-carbon olefins is becoming tight, and production costs are increasing. Methanol, as an alternative energy source, is widely available and can be produced from coal, natural gas, and biomass. Its total production capacity is continuously growing worldwide, with supply consistently exceeding demand. Currently, the technology for producing low-carbon olefins such as ethylene and propylene from methanol (MTO) has matured and has become the most promising alternative to the naphtha route for olefin production.

[0004] Most enterprises producing low-carbon olefins are equipped with facilities that use petroleum hydrocarbons as raw materials to produce low-carbon olefins. Under existing technology, it is possible to use existing petroleum hydrocarbon catalytic cracking facilities to produce low-carbon olefins by combining petroleum hydrocarbon catalytic cracking with methanol-to-olefins (MTO). However, there are problems such as the inability to control the petroleum hydrocarbon catalytic cracking unit and the MTO unit independently, and the small amount of catalyst in the MTO unit, resulting in a low proportion of methanol feedstock. Summary of the Invention

[0005] This invention provides an apparatus for the combined production of olefins from petroleum hydrocarbon catalytic cracking and methanol-to-olefins (MTO). Based on existing catalytic cracking units, this apparatus combines petroleum hydrocarbon catalytic cracking and MTO reactions, allowing independent control of reaction conditions in both units. The catalyst density in the MTO unit can be flexibly adjusted, thereby significantly increasing the methanol feed ratio to the catalytic cracking unit, maximizing the MTO reaction, and increasing the ethylene and propylene content in the catalytic cracking gas products.

[0006] The present invention also provides a method for preparing olefins by combining petroleum hydrocarbon catalytic cracking and methanol-to-olefins using the above-described apparatus.

[0007] The first aspect of the present invention provides an apparatus for the combined preparation of olefins by petroleum hydrocarbon catalytic cracking and methanol-to-olefins, comprising a petroleum hydrocarbon catalytic cracking unit, a first gas-solid separation unit, a stripping unit, a methanol-to-olefins unit, a catalyst regeneration unit, a second gas-solid separation unit, and a catalyst mixing unit.

[0008] The product outlet of the petroleum hydrocarbon catalytic cracking unit is connected to the first inlet of the first gas-solid separation unit; the solid phase outlet of the first gas-solid separation unit is connected to the stripping material inlet of the stripping unit; the first stripping material outlet of the stripping unit is connected to the first catalyst inlet of the catalyst mixing unit; the catalyst outlet of the catalyst mixing unit is connected to the catalyst inlet of the methanol-to-olefins unit; the gas phase outlet of the catalyst mixing unit is connected to the second inlet of the first gas-solid separation unit; the catalyst outlet of the methanol-to-olefins unit is connected to the first catalyst inlet of the catalyst regeneration unit; the outlet of the catalyst regeneration unit is connected to the separation material inlet of the second gas-solid separation unit; the first catalyst outlet of the second gas-solid separation unit is connected to the second catalyst inlet of the catalyst mixing unit; and the second catalyst outlet of the second gas-solid separation unit is connected to the catalyst inlet of the petroleum hydrocarbon catalytic cracking unit.

[0009] The apparatus described above further includes a catalyst heat extraction unit;

[0010] The first catalyst outlet of the second gas-solid separation unit is connected to the catalyst inlet of the catalyst heating unit, the first catalyst outlet of the catalyst heating unit is connected to the second inlet of the catalyst mixing unit, and the second catalyst outlet of the catalyst heating unit is connected to the catalyst inlet of the second gas-solid separation unit.

[0011] In the apparatus described above, the stripping unit further includes a second stripped product outlet, which is connected to the second catalyst inlet of the catalyst regeneration unit.

[0012] A second aspect of the present invention provides a method for preparing olefins by a combination of petroleum hydrocarbon catalytic cracking and methanol-to-olefins, wherein the method is performed by the apparatus described above.

[0013] The method described above includes the following steps:

[0014] The feedstock, including petroleum hydrocarbons and a catalyst, is introduced into the petroleum hydrocarbon catalytic cracking unit through the feedstock inlet of the petroleum hydrocarbon catalytic cracking unit to carry out a first reaction, and a first product including a first catalyst to be regenerated and a first olefin gas is obtained.

[0015] The first product is fed into the first gas-solid separation unit through the product outlet of the petroleum hydrocarbon catalytic cracking unit to undergo first gas-solid separation, resulting in a first catalyst to be regenerated and a first olefin gas. The first olefin gas is output through the gas phase outlet of the first gas-solid separation unit, and the first catalyst to be regenerated is fed into the stripping unit for stripping treatment to obtain a stripped catalyst to be regenerated.

[0016] The stripping catalyst to be regenerated enters the catalyst mixing unit through the first catalyst inlet of the catalyst mixing unit, and mixes with the regenerated catalyst that is fed into the second catalyst inlet of the catalyst mixing unit through the first catalyst outlet of the second gas-solid separation unit. The mixture then enters the methanol-to-olefins unit and undergoes a second reaction with the methanol in the methanol-to-olefins unit to obtain the second catalyst to be regenerated and the second olefin gas.

[0017] The second olefin gas enters the first gas-solid separation unit through the outlet of the catalyst mixing unit and is output from the gas phase outlet of the first gas-solid separation unit;

[0018] The second catalyst to be regenerated enters the catalyst regeneration unit through the first catalyst inlet of the catalyst regeneration unit for catalyst regeneration treatment, resulting in a second product including regenerated flue gas and regenerated catalyst. The second product then enters the second gas-solid separation unit through the outlet of the catalyst regeneration unit for second gas-solid separation, resulting in regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the second gas-solid separation unit, and the regenerated catalyst is input to the catalyst mixing unit and the petroleum hydrocarbon catalytic cracking unit through the first catalyst outlet and the second catalyst outlet of the second gas-solid separation unit, respectively.

[0019] In the method described above, the regenerated catalyst is fed into the catalyst inlet of the catalyst heating unit through the first catalyst outlet of the second gas-solid separation unit to cool the regenerated catalyst. The partially cooled regenerated catalyst is then fed into the catalyst mixing unit through the second catalyst inlet of the catalyst mixing unit to mix with the stripped catalyst to be regenerated.

[0020] Part of the cooled regenerated catalyst is returned to the second gas-solid separation unit via the catalyst inlet of the second gas-solid separation unit.

[0021] In the method described above, in the stripping unit, a portion of the stripped catalyst to be regenerated enters the catalyst regeneration unit through the second stripped product outlet of the stripping unit, and the remaining portion of the stripped catalyst to be regenerated enters the catalyst mixing unit through the first stripped product outlet of the stripping unit.

[0022] In the method described above, the reaction conditions for the first reaction are: a reaction temperature of 480–600°C, a mass ratio of the catalyst to petroleum hydrocarbon feedstock of 4–20, a reaction time of 0.5–8 s, and a mass ratio of atomized steam to petroleum hydrocarbon feedstock of 0.02–0.2.

[0023] And / or, the reaction conditions for the second reaction are: a reaction temperature of 420-520°C, a mass ratio of the stripping catalyst to be regenerated to methanol feedstock of 10-100, a reaction time of 0.5-10s, and a mass ratio of water to methanol in the methanol feedstock of 0-1.

[0024] In the method described above, the mass ratio of methanol feedstock entering the methanol-to-olefins unit to petroleum hydrocarbon feedstock entering the petroleum hydrocarbon catalytic cracking unit is 0.01 to 3.

[0025] In the method described above, the mass ratio of the stripping catalyst to be regenerated entering through the first catalyst inlet of the catalyst mixing unit to the regenerated catalyst entering through the second catalyst inlet of the catalyst mixing unit is (2-10):(0-8).

[0026] And / or, the mass ratio of the stripped catalyst to be regenerated entering the catalyst mixing unit from the stripping unit to the stripped catalyst to be regenerated entering the catalyst regeneration unit from the stripping unit is (2-10):(0-8);

[0027] And / or, the mass ratio of the cooled regenerated catalyst entering the catalyst mixing unit from the catalyst heating unit to the cooled regenerated catalyst entering the second gas-solid separation unit from the catalyst heating unit is (0-10):(0-10).

[0028] The apparatus for combined petroleum hydrocarbon catalytic cracking and methanol-to-olefins (MTO) production provided by this invention adds a MTO unit to an existing catalytic cracking unit, thereby enabling simultaneous petroleum hydrocarbon catalytic cracking and MTO reactions within the same unit, reducing the equipment cost of building a separate MTO unit. Furthermore, the reaction conditions in the petroleum hydrocarbon catalytic cracking unit and the MTO unit can be independently controlled, avoiding competition between petroleum hydrocarbons and methanol during simultaneous reactions. The catalyst density in the MTO unit can be flexibly adjusted, significantly increasing the methanol feed ratio to the catalytic cracking unit, maximizing the MTO reaction, and increasing the ethylene and propylene content in the catalytic cracking gas products. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 is a schematic diagram of an apparatus for preparing olefins by combining petroleum hydrocarbon catalytic cracking and methanol-to-olefins in one embodiment of the present invention.

[0031] Figure 2 is a schematic diagram of an apparatus for preparing olefins by combining petroleum hydrocarbon catalytic cracking and methanol-to-olefins in one embodiment of the present invention;

[0032] Figure 3 is a schematic diagram of an apparatus for preparing olefins by combining petroleum hydrocarbon catalytic cracking and methanol-to-olefins in one embodiment of the present invention.

[0033] Figure 4 is a schematic diagram of the apparatus for preparing olefins by catalytic cracking of petroleum hydrocarbons provided in the comparative example of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1- Petroleum hydrocarbon feedstocks;

[0036] 2-Pre-lift air;

[0037] 3-Petroleum hydrocarbon catalytic cracking unit;

[0038] 4-First gas-solid separation unit;

[0039] 5-Stripping unit;

[0040] 6-Methanol to Olefins Unit;

[0041] 7-Methanol feedstock;

[0042] 8-Stripping steam;

[0043] 9-First connecting pipe;

[0044] 10 - Catalyst regeneration unit;

[0045] 11-Second gas-solid separation unit;

[0046] 12-Second connecting pipe;

[0047] 13-Regenerated prevailing wind;

[0048] 14-Regenerated flue gas;

[0049] 15-olefin gases;

[0050] 16 - Sixth connecting pipe;

[0051] 17 - Fifth connecting pipe;

[0052] 18-Third connecting pipe;

[0053] 19-Fourth connecting pipe;

[0054] 20-Catalyst Mixing Unit;

[0055] 21-Catalyst heat extraction unit. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0057] The first aspect of the present invention provides an apparatus for the combined preparation of olefins by petroleum hydrocarbon catalytic cracking and methanol-to-olefins, as shown in FIG1, including a petroleum hydrocarbon catalytic cracking unit 3, a first gas-solid separation unit 4, a stripping unit 5, a methanol-to-olefins unit 6, a catalyst regeneration unit 10, a second gas-solid separation unit 11, and a catalyst mixing unit 20.

[0058] The product outlet of the petroleum hydrocarbon catalytic cracking unit 3 is connected to the first inlet of the first gas-solid separation unit 4. The solid phase outlet of the first gas-solid separation unit 4 is connected to the stripping material inlet of the stripping unit 5. The first stripping material outlet of the stripping unit 5 is connected to the first catalyst inlet of the catalyst mixing unit 20. The catalyst outlet of the catalyst mixing unit 20 is connected to the catalyst inlet of the methanol-to-olefins unit 6. The gas phase outlet of the catalyst mixing unit 20 is connected to the second inlet of the first gas-solid separation unit 4. The catalyst outlet of the methanol-to-olefins unit 6 is connected to the first catalyst inlet of the catalyst regeneration unit 10. The outlet of the catalyst regeneration unit 10 is connected to the separation material inlet of the second gas-solid separation unit 11. The first catalyst outlet of the second gas-solid separation unit 11 is connected to the second catalyst inlet of the catalyst mixing unit 20. The second catalyst outlet of the second gas-solid separation unit 11 is connected to the catalyst inlet of the petroleum hydrocarbon catalytic cracking unit 3.

[0059] In this invention, the petroleum hydrocarbon catalytic cracking unit 3, the first gas-solid separation unit 4, the stripping unit 5, the methanol-to-olefins unit 6, the catalyst regeneration unit 10, the second gas-solid separation unit 11, and the catalyst mixing unit 20 are all conventional equipment in the art. For example, the petroleum hydrocarbon catalytic cracking unit 3 is a riser reactor; the first gas-solid separation unit 4 and the second gas-solid separation unit 11 are settlers; the stripping unit 5 is a stripper; the methanol-to-olefins unit 6 is a fluidized bed reactor, specifically one of a fast fluidized bed, a turbulent fluidized bed, a dispersed fluidized bed, or a dense phase fluidized bed; the catalyst regeneration unit 10 is a catalytic cracking regenerator; and the catalyst mixing unit 20 is a catalyst mixer.

[0060] The apparatus for the combined production of olefins from petroleum hydrocarbon catalytic cracking and methanol-to-olefins (MTO) of the present invention, based on an existing catalytic cracking unit, adds a MTO unit 6 and a catalyst mixing unit 20. This allows for the simultaneous occurrence of petroleum hydrocarbon catalytic cracking and MTO reactions within the same unit. By separately configuring the MTO unit 6 and the petroleum hydrocarbon catalytic cracking unit 3, independent control of the petroleum hydrocarbon reaction and the methanol reaction is achieved. The catalyst regeneration unit 10 and the catalyst mixing unit 20 are connected via a fourth connecting pipe 19. By adding the catalyst mixing unit 20, the regenerated catalyst can be returned to the MTO unit 6, increasing the density of the catalyst entering the MTO unit 6 as needed, thus enhancing the adjustability of the materials in the reaction. This significantly increases the methanol feed ratio of the catalytic cracking unit, maximizing the MTO reaction and increasing the content of ethylene and propylene in the catalytic cracking gas products.

[0061] In one specific embodiment, the first gas-solid separation unit 4 and the stripping unit 5 are integrated in the direction of gravity and are coaxially connected in sequence; the catalyst mixing unit 20 and the methanol-to-olefins unit 6 are integrated in the direction of gravity and are coaxially connected in sequence; the second gas-solid separation unit 11 and the catalyst regeneration unit 10 are integrated in the direction of gravity and are coaxially connected in sequence.

[0062] The above-mentioned device uses a coaxial connection, which can ensure efficient and rapid separation of the gas and solid phases, reduce secondary reactions, and at the same time, the catalyst descends by its own gravity, which can reduce the energy consumption for catalyst transportation.

[0063] As shown in Figure 2, in one specific embodiment, a catalyst heat extraction unit 21 is also included;

[0064] The first catalyst outlet of the second gas-solid separation unit 11 is connected to the catalyst inlet of the catalyst heating unit 21, the first catalyst outlet of the catalyst heating unit 21 is connected to the second inlet of the catalyst mixing unit 20, and the second catalyst outlet of the catalyst heating unit 21 is connected to the catalyst inlet of the second gas-solid separation unit 11.

[0065] The catalyst heat extraction unit 21 is a commonly used heat extraction device in the field, such as a catalyst heat extractor.

[0066] By setting up a catalyst heat extraction unit 21, the regenerated catalyst in the catalyst regeneration unit 10 is cooled before entering the catalyst mixing unit 20, thereby bringing the catalyst in the catalyst mixing unit 20 to a suitable temperature. The catalyst heat extraction unit 21 can then circulate the cooled regenerated catalyst back to the second gas-solid separation unit 11, preventing overheating inside the second gas-solid separation unit 11 and causing equipment damage.

[0067] As shown in Figure 3, in one specific embodiment, the stripping unit 5 further includes a second stripped material outlet, which is connected to the second catalyst inlet of the catalyst regeneration unit 10.

[0068] The stripping unit 5 and the catalyst regeneration unit 10 are connected via a sixth connecting pipe 16. The stripped catalyst to be regenerated in the stripping unit 5 can be directly input into the catalyst regeneration unit 10 through the sixth connecting pipe 16, thereby enhancing the adjustability of the catalyst throughout the entire unit. When the methanol-to-olefins unit 6 has a small methanol throughput or requires high catalyst activity, a portion of the stripped catalyst to be regenerated can be directly input into the catalyst regeneration unit 10 for regeneration.

[0069] A second aspect of the present invention provides a method for preparing olefins by a combination of petroleum hydrocarbon catalytic cracking and methanol-to-olefins, which is carried out by the above-described apparatus.

[0070] In one specific implementation, the following steps are included:

[0071] The feedstock, including petroleum hydrocarbons 1 and the catalyst, is introduced into the petroleum hydrocarbon catalytic cracking unit 3 through the feedstock inlet of the petroleum hydrocarbon catalytic cracking unit 3 to carry out the first reaction, and a first product including the first catalyst to be regenerated and the first olefin gas is obtained.

[0072] The first product is fed into the first gas-solid separation unit 4 through the product outlet of the petroleum hydrocarbon catalytic cracking unit 3 for first gas-solid separation to obtain the first catalyst to be regenerated and the first olefin gas. The first olefin gas is output through the gas phase outlet of the first gas-solid separation unit 4, and the first catalyst to be regenerated is fed into the stripping unit 5 for stripping treatment to obtain the stripped catalyst to be regenerated.

[0073] The stripping catalyst to be regenerated enters the catalyst mixing unit 20 through the first catalyst inlet of the catalyst mixing unit 20, and mixes with the regenerated catalyst that is fed into the second catalyst inlet of the catalyst mixing unit 20 through the first catalyst outlet of the second gas-solid separation unit 11. The mixture then enters the methanol-to-olefins unit 6 and undergoes a second reaction with the methanol in the methanol-to-olefins unit 6 to obtain the second catalyst to be regenerated and the second olefin gas. The second olefin gas enters the first gas-solid separation unit 4 through the outlet of the catalyst mixing unit and is output from the gas phase outlet of the first gas-solid separation unit 4.

[0074] The second catalyst to be regenerated enters the catalyst regeneration unit 10 through the first catalyst inlet of the catalyst regeneration unit 10 for catalyst regeneration treatment, and obtains a second product including regenerated flue gas and regenerated catalyst.

[0075] The second product is introduced into the second gas-solid separation unit 11 through the outlet of the catalyst regeneration unit 10 for second gas-solid separation to obtain regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the second gas-solid separation unit 11, and the regenerated catalyst is input into the catalyst mixing unit 20 and the petroleum hydrocarbon catalytic cracking unit 3 through the first catalyst outlet and the second catalyst outlet of the second gas-solid separation unit 11, respectively.

[0076] In one specific embodiment, the above method includes the following steps:

[0077] Step 1: The feedstock, including petroleum hydrocarbons 1 and the catalyst, is introduced into the petroleum hydrocarbon catalytic cracking unit 3 through the feedstock inlet of the petroleum hydrocarbon catalytic cracking unit 3 to carry out the first reaction, and the first product, including the first catalyst to be regenerated and the first olefin gas, is obtained.

[0078] The first reaction, catalytic cracking, refers to the process by which hydrocarbons with relatively large molecular weights and high boiling points (petroleum hydrocarbon feedstocks) are broken down into hydrocarbons with relatively small molecular weights and lower boiling points (such as ethylene, propylene, and butene) under the action of heat and a catalyst. During the reaction, non-volatile carbonaceous substances deposit on the catalyst and condense into coke, causing a decrease in catalyst activity. To enable the catalyst to be recycled, it needs to be regenerated to restore its activity.

[0079] Petroleum hydrocarbon feedstock 1 includes at least one of naphtha, gasoline, diesel, distillate oil, and crude oil.

[0080] Furthermore, in petroleum hydrocarbon feedstock 1, the mass percentage of the 0–370℃ fraction is 0–100%, and the mass percentage of the fraction above 370℃ is 0–100%.

[0081] The catalyst raw material 17 includes a molecular sieve, a support, and a binder. The molecular sieve includes at least one of rare earth-containing USY molecular sieve, rare earth-free USY molecular sieve, β molecular sieve, ZSM molecular sieve, or Sapo molecular sieve. The support is at least one of silica, alumina, kaolin, and montmorillonite. The binder is at least one of silica sol, alumina sol, and boehmite.

[0082] In one specific embodiment, the reaction conditions for the first reaction are as follows: the reaction temperature is 480–600°C, the mass ratio of catalyst to petroleum hydrocarbon feedstock is 4–20, the reaction time is 0.5–8 s, and the mass ratio of atomized steam to petroleum hydrocarbon feedstock is 0.02–0.2.

[0083] Preferably, the reaction conditions for the first reaction are: a reaction temperature of 500°C, a mass ratio of catalyst to petroleum hydrocarbon feedstock of 7, a reaction time of 2 seconds, and a mass ratio of atomized steam to petroleum hydrocarbon feedstock of 0.1.

[0084] Step 2: The first product is fed into the first gas-solid separation unit 4 through the product outlet of the petroleum hydrocarbon catalytic cracking unit 3 for first gas-solid separation to obtain the first catalyst to be regenerated and the first olefin gas. The first olefin gas is output through the gas phase outlet of the first gas-solid separation unit 4, and the first catalyst to be regenerated is fed into the stripping unit 5 for stripping treatment to obtain the stripped catalyst to be regenerated.

[0085] The first product in step 1 is a mixture of gaseous and solid phases containing a first olefin gas and a first catalyst to be regenerated. After entering the first gas-solid separation unit 4, it undergoes first gas-solid separation to obtain the first catalyst to be regenerated and the first olefin gas. The first olefin gas is output through the gas phase outlet of the first gas-solid separation unit 4, as shown in Figure 1 as olefin gas 15. Some of the first olefin gas is adsorbed on the surface of the first catalyst to be regenerated. The first catalyst to be regenerated then enters the stripping unit 5 for stripping treatment, separating the adsorbed first olefin gas from the catalyst to obtain a stripped catalyst to be regenerated.

[0086] Step 3: The stripping catalyst to be regenerated enters the catalyst mixing unit 20 through the first catalyst inlet of the catalyst mixing unit 20, and mixes with the regenerated catalyst that is fed into the second catalyst inlet of the catalyst mixing unit 20 through the first catalyst outlet of the second gas-solid separation unit 11. The mixture then enters the methanol-to-olefins unit 6 and undergoes a second reaction with the methanol in the methanol-to-olefins unit 6 to obtain the second catalyst to be regenerated and the second olefin gas. The second olefin gas enters the first gas-solid separation unit 4 through the outlet of the catalyst mixing unit and is output from the gas phase outlet of the first gas-solid separation unit 4.

[0087] The second reaction, namely the methanol-to-olefins reaction, refers to the conversion of methanol into olefins (ethylene, propylene, and butene, etc.) using methanol as a raw material through the action of a catalyst. The reaction process is as follows:

[0088] 2CH3OH→C2H4+2H2O

[0089] 3CH3OH→C3H6+3H2O

[0090] 4CH3OH→C4H8+4H2O

[0091] According to the above reaction formula, the reaction products are only olefins and water, and no other toxic or harmful substances are generated.

[0092] The reaction mechanism of methanol to olefins is very complex. The "carbon pool" mechanism is currently the most widely accepted. The "carbon pool" mechanism suggests that methanol first forms some hydrocarbons with relatively large molecular weights in the catalyst channels and adsorbs them in the catalyst channels. On the one hand, these substances act as active centers and continuously react with methanol to introduce methoxy groups. On the other hand, these active centers continuously carry out dehydrogenation, hydrogen transfer, alkylation and other reactions to generate low-carbon olefins such as ethylene, propylene, and butene.

[0093] The first catalyst to be regenerated, produced from the catalytic cracking reaction of petroleum hydrocarbon feedstock, is stripped to obtain a stripped catalyst to be regenerated. This stripped catalyst then enters the methanol-to-olefins (MTO) unit 6 to participate in the MTO reaction. The first catalyst to be regenerated has polycyclic components attached to it, which can provide an abundant "carbon pool" for the MTO reaction, initiating and promoting the rapid conversion of methanol into low-carbon olefins.

[0094] In one specific embodiment, the mass ratio of the regenerated catalyst entering through the second catalyst inlet of the catalyst mixing unit 20 to the stripping catalyst to be regenerated entering through the first catalyst inlet of the catalyst mixing unit 20 is (0-10):(0-10).

[0095] By controlling the mass ratio of the regenerated catalyst entering the catalyst mixing unit 20 to the stripping catalyst to be regenerated, the amount and density of the catalyst entering the methanol-to-olefins unit 6 can be controlled, allowing the methanol-to-olefins process to be adjusted within a wide range of catalyst-to-methanol ratios; the activity of the catalyst entering the methanol-to-olefins unit 6 can be adjusted within a wide range, increasing the flexibility of the unit's processing.

[0096] Furthermore, the mass ratio of the regenerated catalyst entering through the second catalyst inlet of the catalyst mixing unit 20 to the stripping catalyst to be regenerated entering through the first catalyst inlet of the catalyst mixing unit 20 is (2-6):(4-8).

[0097] In one specific embodiment, as shown in Figure 2, the regenerated catalyst is input from the first catalyst outlet of the second gas-solid separation unit 11 to the catalyst inlet of the catalyst heating unit 21 to cool down the regenerated catalyst. Part of the cooled regenerated catalyst enters the catalyst mixing unit 20 through the second catalyst inlet of the catalyst mixing unit 20 and is mixed with the first catalyst to be regenerated. Part of the cooled regenerated catalyst returns to the second gas-solid separation unit 11 through the catalyst inlet of the second gas-solid separation unit 11.

[0098] By setting a catalyst heat extraction unit 21 between the catalyst regeneration unit 10 and the catalyst mixing unit 20, the temperature of the regenerated catalyst entering the catalyst mixing unit 20 can be regulated. This allows for temperature regulation of the catalyst entering the methanol-to-olefins unit 6 within a wider range. The catalyst heat extraction unit 21 can also circulate the cooled regenerated catalyst to the second gas-solid separation unit 11, preventing overheating inside the second gas-solid separation unit 11 and potential equipment damage.

[0099] In one specific embodiment, the mass ratio of the cooled regenerated catalyst entering the catalyst mixing unit 20 from the catalyst heat extraction unit 21 to the cooled regenerated catalyst entering the catalyst regeneration unit 10 from the catalyst heat extraction unit 21 is (0-10):(0-10).

[0100] The mass ratio of the regenerated catalyst cooled in the catalyst heating unit 21 to the catalyst mixing unit 20 and the catalyst regeneration unit 10 can be flexibly adjusted according to the amount of catalyst required in the methanol-to-olefins unit 6.

[0101] In one specific embodiment, the reaction conditions for the second reaction are as follows: the reaction temperature is 420-520°C, the mass ratio of the stripping catalyst to be regenerated to the methanol feedstock is 10-100, the reaction time is 0.5-10s, and the mass ratio of water to methanol in the methanol feedstock is 0-1.

[0102] Preferably, the reaction conditions for the second reaction are: a reaction temperature of 480°C, a mass ratio of stripping catalyst to methanol feedstock of 30, a reaction time of 5 seconds, and a mass ratio of water to methanol in the methanol feedstock of 0.2.

[0103] By controlling parameters such as reaction temperature, reaction time, and material ratio of the first and second reactions, both material costs and reaction efficiency can be balanced, maximizing the production of high-value products and improving the economic benefits of the equipment.

[0104] Step 4: The second catalyst to be regenerated enters the catalyst regeneration unit 10 through the first catalyst inlet of the catalyst regeneration unit 10 for catalyst regeneration treatment, and a second product including regenerated flue gas and regenerated catalyst is obtained.

[0105] The second product is introduced into the second gas-solid separation unit 11 through the outlet of the catalyst regeneration unit 10 for second gas-solid separation to obtain regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the second gas-solid separation unit 11, and the regenerated catalyst is input into the catalyst mixing unit 20 and the petroleum hydrocarbon catalytic cracking unit 3 through the first catalyst outlet and the second catalyst outlet of the second gas-solid separation unit 11, respectively.

[0106] The catalyst feedstock sequentially participates in the catalytic cracking reaction of petroleum hydrocarbons and the methanol-to-olefins reaction, transforming into a second catalyst to be regenerated. In order to realize the recycling of the catalyst in the reaction process, the second catalyst to be regenerated needs to be regenerated.

[0107] The commonly used catalyst regeneration method is thermal oxidation regeneration, which involves placing the spent catalyst into a high-temperature regenerator for treatment. Oxygen from the air is used to remove impurities such as coke adhering to the catalyst particles under high-temperature oxidation. As shown in Figure 1, the second catalyst to be regenerated enters the catalyst regeneration unit 10 through the catalyst outlet of the methanol-to-olefins unit 6 for catalyst regeneration treatment, yielding a second product containing regenerated flue gas and regenerated catalyst.

[0108] Similar to the first product, the second product is a mixture of gaseous and solid phases containing regenerated flue gas and regenerated catalyst, as shown in Figure 1. The second product enters the second gas-solid separation unit 11 through the outlet of the catalyst regeneration unit 10 for second gas-solid separation to obtain regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the second gas-solid separation unit 11, as marked 14 in the figure. The regenerated catalyst is input into the catalyst mixing unit 20 and the petroleum hydrocarbon catalytic cracking unit 3 through the fourth connecting pipe 19 and the second connecting pipe 12, respectively, thereby realizing the recycling of the catalyst in the reaction process.

[0109] In one specific embodiment, the mass ratio of methanol feedstock entering the methanol-to-olefins unit to petroleum hydrocarbon feedstock entering the petroleum hydrocarbon catalytic cracking unit is 0.01 to 3.

[0110] This invention can significantly increase the feed ratio of methanol, thereby maximizing the methanol-to-olefins reaction, increasing the content of ethylene and propylene in the catalytic cracking gas products, and making subsequent ethylene and propylene purification more convenient.

[0111] In one specific embodiment, as shown in Figure 3, in the stripping unit 5, part of the stripped catalyst to be regenerated enters the catalyst regeneration unit 10 through the second stripped material outlet of the stripping unit 5, and the remaining part of the stripped catalyst to be regenerated enters the catalyst mixing unit 20 through the first stripped material outlet of the stripping unit 5.

[0112] Furthermore, the mass ratio of the stripped catalyst to be regenerated entering the catalyst mixing unit 20 from the stripping unit 5 to the stripped catalyst to be regenerated entering the catalyst regeneration unit 10 from the stripping unit 5 is (2-10):(0-8).

[0113] In the methanol-to-olefins reaction, the mass ratio of catalyst to methanol feedstock needs to be appropriate. By controlling the input and output ratio of catalyst in each reaction unit, the content and activity of catalyst in each reaction unit can be flexibly adjusted. In particular, the catalyst density in methanol-to-olefins unit 6 can be increased as needed, thereby increasing the feed ratio of methanol feedstock, maximizing the methanol-to-olefins reaction, and increasing the content of ethylene and propylene in the catalytic cracking gas products.

[0114] The solution provided by the present invention will be further described below with reference to specific embodiments.

[0115] Example 1

[0116] Referring to Figure 2, the preheated diesel feedstock is injected into the riser reactor and comes into contact with the regenerated catalyst from the second connecting pipeline 12, which has been boosted by the pre-boosting gas 2, and reacts to obtain a first product including the first catalyst to be regenerated and the first olefin gas.

[0117] The first product enters the settler, the first catalyst to be regenerated and the first olefin gas undergo gas-solid separation, the first olefin gas is output through the gas phase outlet of the settler, and the first catalyst to be regenerated enters the stripper and is stripped under the action of stripping steam 8 to obtain the stripped catalyst to be regenerated.

[0118] The stripping catalyst to be regenerated is entirely fed into the catalyst mixer via the third connecting pipe 18, where it is mixed with the regenerated catalyst from the regenerator and cooled by the heat exchanger. The mixture then enters the fluidized bed reactor. Preheated methanol feedstock 7 is injected from the bottom of the fluidized bed reactor and reacts with the mixed catalyst to produce a second catalyst to be regenerated and a second olefin gas. The second olefin gas enters upwards into the settling tank via the fifth connecting pipe 17 and is output from the gas phase outlet of the settling tank.

[0119] The second catalyst to be regenerated enters the regenerator through the first connecting pipe 9 for coking treatment, resulting in regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the regenerator. The regenerated catalyst enters the riser reactor and the catalyst mixer through the second connecting pipe 12 and the fourth connecting pipe 19, respectively. The second product enters the reaction settling tank upward and mixes with the first product, then enters the subsequent product separation system. The regenerated flue gas enters the subsequent energy recovery system through the regenerated flue gas pipeline. When the catalyst is regenerated, the main regeneration air 13 is introduced into the catalyst regeneration unit 10.

[0120] In this embodiment, the reaction conditions for the catalytic cracking reaction are: reaction temperature of 500℃, mass ratio of catalyst to petroleum hydrocarbon feedstock of 7, reaction time of 2s, and mass ratio of atomized steam to petroleum hydrocarbon feedstock of 0.1; the reaction conditions for the methanol-to-olefins reaction are: reaction temperature of 480℃, mass ratio of stripping catalyst to methanol feedstock of 50, reaction time of 5s, and mass ratio of water to methanol in the methanol feedstock of 0.2.

[0121] The ratio of methanol feedstock to diesel is 1; the mass ratio of the regenerated catalyst entering through the second inlet of the catalyst mixing unit to the stripped catalyst to be regenerated entering through the first inlet of the catalyst mixing unit is 2:8; the mass ratio of the cooled regenerated catalyst entering the catalyst mixing unit from the catalyst heat extraction unit to the cooled regenerated catalyst entering the catalyst regeneration unit from the catalyst heat extraction unit is 5:5.

[0122] The properties of the diesel feedstock used are shown in Table 1, and the distribution of the obtained products is shown in Table 3.

[0123] Example 2

[0124] As shown in Figure 3, the preheated diesel feedstock is injected into the riser reactor and comes into contact with the regenerated catalyst from the second connecting pipeline 12, which has been lifted by the pre-lifting gas 2, and reacts to obtain a first product including the first catalyst to be regenerated and the first olefin gas.

[0125] The first product enters the settler, the first catalyst to be regenerated and the first olefin gas undergo gas-solid separation, the first olefin gas is output through the gas phase outlet of the settler, and the first catalyst to be regenerated enters the stripper 5 for stripping treatment to obtain the stripped catalyst to be regenerated.

[0126] 50% of the stripped catalyst to be regenerated is fed into the catalyst mixer via the third connecting pipe 18, where it is mixed with the regenerated catalyst from the regenerator and cooled by the heat exchanger. The mixture then enters the fluidized bed reactor. The remaining 50% of the stripped catalyst to be regenerated is fed into the regenerator via the sixth connecting pipe 16 for catalyst regeneration.

[0127] After being preheated, methanol feedstock 7 is injected from the bottom of the fluidized bed reactor and reacts with the mixed catalyst to produce methanol-to-olefins reaction, resulting in a second catalyst to be regenerated and a second olefin gas. The second olefin gas enters the settler upward through the fifth connecting pipe 17 and is output from the gas phase outlet of the settler.

[0128] The second catalyst to be regenerated enters the regenerator through the first connecting pipe 9 for catalyst regeneration treatment, resulting in regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the regenerator. The regenerated catalyst enters the riser reactor 3 and the catalyst mixer through the second connecting pipe 12 and the fourth connecting pipe 19, respectively. The second product enters the reaction settling tank upward and mixes with the first product, then enters the subsequent product separation system. The regenerated flue gas enters the subsequent energy recovery system through the regenerated flue gas pipeline.

[0129] In this embodiment, the reaction conditions for the catalytic cracking reaction are: reaction temperature of 500℃, mass ratio of catalyst to petroleum hydrocarbon feedstock of 7, reaction time of 2s, and mass ratio of atomized steam to petroleum hydrocarbon feedstock of 0.1; the reaction conditions for the methanol-to-olefins reaction are: reaction temperature of 480℃, mass ratio of stripping catalyst to methanol feedstock of 30, reaction time of 5s, and mass ratio of water to methanol in the methanol feedstock of 0.2.

[0130] The ratio of methanol feedstock to diesel is 0.5; the mass ratio of the regenerated catalyst entering through the second catalyst inlet of the catalyst mixing unit to the stripped catalyst to be regenerated entering through the first catalyst inlet of the catalyst mixing unit is 5:5; the mass ratio of the cooled regenerated catalyst entering the catalyst mixing unit from the catalyst heat extraction unit to the cooled regenerated catalyst entering the catalyst regeneration unit from the catalyst heat extraction unit is 2:5.

[0131] The properties of the diesel feedstock used are shown in Table 1, and the distribution of the obtained products is shown in Table 3.

[0132] Example 3

[0133] As shown in Figure 3, the preheated distillate oil feedstock (distillation range 289℃~535℃) is injected into the riser reactor and reacts with the regenerated catalyst from the second connecting pipeline 12, which has been boosted by the pre-lifting gas 2, to obtain a first product including the first catalyst to be regenerated and the first olefin gas.

[0134] The first product enters the settler, the first catalyst to be regenerated and the first olefin gas undergo gas-solid separation, the first olefin gas is output through the gas phase outlet of the settler, and the first catalyst to be regenerated enters the stripper for stripping treatment to obtain the stripped catalyst to be regenerated.

[0135] 50% of the stripped catalyst to be regenerated is fed into the catalyst mixer via the third connecting pipe 18, where it is mixed with the regenerated catalyst from the regenerator and cooled by the heat exchanger. The mixture then enters the fluidized bed reactor. The remaining 50% of the stripped catalyst to be regenerated is fed into the regenerator via the sixth connecting pipe 16 for catalyst regeneration.

[0136] After being preheated, methanol feedstock 7 is injected from the bottom of the fluidized bed reactor and reacts with the mixed catalyst to produce methanol-to-olefins reaction, resulting in a second catalyst to be regenerated and a second olefin gas. The second olefin gas enters the settler upward through the fifth connecting pipe 17 and is output from the gas phase outlet of the settler.

[0137] The second catalyst to be regenerated enters the regenerator through the first connecting pipe 9 for catalyst regeneration treatment, resulting in regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the regenerator. The regenerated catalyst enters the riser reactor 3 and the catalyst mixer 20 through the second connecting pipe 12 and the fourth connecting pipe 19, respectively. The second product enters the reaction settling tank upward and mixes with the first product, then enters the subsequent product separation system. The regenerated flue gas enters the subsequent energy recovery system through the regenerated flue gas pipeline.

[0138] In this embodiment, the reaction conditions for the catalytic cracking reaction are: a reaction temperature of 500°C, a mass ratio of catalyst to petroleum hydrocarbon feedstock of 7, a reaction time of 2s, and a mass ratio of atomized steam to petroleum hydrocarbon feedstock of 0.1; the reaction conditions for the methanol-to-olefins reaction are: a reaction temperature of 480°C, a mass ratio of catalyst to methanol feedstock of 30 in the fluidized bed reactor 6, a reaction time of 5s, and a mass ratio of water to methanol in the methanol feedstock of 0.2.

[0139] The ratio of methanol feedstock to distillate oil is 0.5; the mass ratio of the regenerated catalyst entering through the second inlet of the catalyst mixing unit to the stripped catalyst to be regenerated entering through the first inlet of the catalyst mixing unit is 2:8; the mass ratio of the cooled regenerated catalyst entering the catalyst mixing unit from the catalyst heating unit to the cooled regenerated catalyst entering the catalyst regeneration unit from the catalyst heating unit is 2:5.

[0140] The properties of the distillate oil feedstock used are shown in Table 2, and the product distribution is shown in Table 3.

[0141] Comparative Example

[0142] As shown in Figure 4, the preheated diesel feedstock 1 is injected into the riser reactor, where it comes into contact with the regenerated catalyst from the regenerated inclined tube, which has been lifted by the pre-lifting gas 2, and undergoes a catalytic cracking reaction to obtain a first product including the first catalyst to be regenerated and the first olefin gas.

[0143] The first product enters the settling tank through the product outlet of the riser reactor for the first gas-solid separation, resulting in the first catalyst to be regenerated and the first olefin gas. The first olefin gas is output through the gas phase outlet of the settling tank, and the first catalyst to be regenerated enters the stripper 5 for stripping treatment to obtain the stripped catalyst to be regenerated.

[0144] The stripped catalyst to be regenerated enters the catalytic cracking regenerator through an inclined tube for catalyst regeneration treatment, yielding a second product containing regenerated flue gas and regenerated catalyst.

[0145] The second product is a mixture of gaseous and solid phases containing regenerated flue gas and regenerated catalyst. The second product enters the settling tank through the outlet of the catalytic cracking regenerator for a second gas-solid separation to obtain regenerated flue gas and regenerated catalyst. The regenerated flue gas is output through the gas phase outlet of the settling tank and enters the subsequent energy recovery system, as shown in Figure 3. The regenerated catalyst is input into the riser reactor through the inclined tube through the solid phase outlet of the settling tank, thereby realizing the recycling of the catalyst in the reaction process.

[0146] In this comparative example, the reaction conditions of the riser reactor are as follows: reaction temperature is 500℃, mass ratio of catalyst to petroleum hydrocarbon feedstock is 7, residence time is 2.0s, and mass ratio of atomized steam to petroleum hydrocarbon feedstock is 0.1.

[0147] The properties of the diesel feedstock used are shown in Table 1, and the distribution of the obtained products is shown in Table 3.

[0148] Table 1 Properties of Diesel Feedstock

[0149]

[0150]

[0151] Table 2 Properties of Distillate Oil Feedstock

[0152]

[0153]

[0154] Table 3 Composition of the products in the examples and comparative examples

[0155]

[0156] Note: Propylene selectivity refers to the percentage of propylene by mass in liquefied petroleum gas.

[0157] In this invention, the reaction conditions in the petroleum hydrocarbon catalytic cracking unit and the methanol-to-olefins unit can be controlled independently, and the catalyst density in the methanol-to-olefins unit can be flexibly adjusted, thereby increasing the methanol feed ratio of the catalytic cracking unit. As can be seen from Table 3, the yields of ethylene, propylene, and butene can be increased to a greater extent. The combined feed of petroleum hydrocarbons and methanol can promote the formation of ethylene and propylene, and greatly increase the selectivity of propylene in liquefied petroleum gas.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An apparatus for the combined production of olefins from petroleum hydrocarbon catalytic cracking and methanol-to-olefins, characterized in that, The system includes a petroleum hydrocarbon catalytic cracking unit, a first gas-solid separation unit, a stripping unit, a methanol-to-olefins unit, a catalyst regeneration unit, a second gas-solid separation unit, and a catalyst mixing unit. The product outlet of the petroleum hydrocarbon catalytic cracking unit is connected to the first inlet of the first gas-solid separation unit; the solid phase outlet of the first gas-solid separation unit is connected to the stripping material inlet of the stripping unit; the first stripping material outlet of the stripping unit is connected to the first catalyst inlet of the catalyst mixing unit; the catalyst outlet of the catalyst mixing unit is connected to the catalyst inlet of the methanol-to-olefins unit; the gas phase outlet of the catalyst mixing unit is connected to the second inlet of the first gas-solid separation unit; the catalyst outlet of the methanol-to-olefins unit is connected to the first catalyst inlet of the catalyst regeneration unit; the outlet of the catalyst regeneration unit is connected to the stripping material inlet of the second gas-solid separation unit; the first catalyst outlet of the second gas-solid separation unit is connected to the second catalyst inlet of the catalyst mixing unit; and the second catalyst outlet of the second gas-solid separation unit is connected to the catalyst inlet of the petroleum hydrocarbon catalytic cracking unit.

2. The apparatus according to claim 1, characterized in that, It also includes a catalyst heating unit; the first catalyst outlet of the second gas-solid separation unit is connected to the catalyst inlet of the catalyst heating unit, the first catalyst outlet of the catalyst heating unit is connected to the second inlet of the catalyst mixing unit, and the second catalyst outlet of the catalyst heating unit is connected to the catalyst inlet of the second gas-solid separation unit.

3. The apparatus according to claim 1 or 2, characterized in that, The stripping unit further includes a second stripped product outlet, which is connected to the second catalyst inlet of the catalyst regeneration unit.

4. A method for preparing olefins by combining petroleum hydrocarbon catalytic cracking and methanol-to-olefins, characterized in that, Performed by the apparatus described in any one of claims 1 to 3.

5. The method according to claim 4, characterized in that, The process includes the following steps: A feedstock comprising petroleum hydrocarbons and a catalyst is introduced into the petroleum hydrocarbon catalytic cracking unit via the feedstock inlet to undergo a first reaction, yielding a first product comprising a first catalyst to be regenerated and a first olefin gas; the first product is then introduced into a first gas-solid separation unit via the product outlet of the petroleum hydrocarbon catalytic cracking unit for first gas-solid separation, yielding the first catalyst to be regenerated and the first olefin gas, wherein the first olefin gas is output via the gas phase outlet of the first gas-solid separation unit, and the first catalyst to be regenerated is introduced into a stripping unit for stripping treatment to obtain a stripped catalyst to be regenerated; the stripped catalyst to be regenerated is introduced into the catalyst mixing unit via the first catalyst inlet of the catalyst mixing unit, and mixed with the regenerated catalyst introduced into the second catalyst inlet of the catalyst mixing unit via the first catalyst outlet of the second gas-solid separation unit, and then... The catalyst is fed into the methanol-to-olefins (MTO) unit and undergoes a second reaction with methanol in the MTO unit to obtain a second catalyst to be regenerated and a second olefin gas. The second olefin gas enters the first gas-solid separation unit through the outlet of the catalyst mixing unit and is output from the gas phase outlet of the first gas-solid separation unit. The second catalyst to be regenerated enters the catalyst regeneration unit through the first catalyst inlet of the catalyst regeneration unit for catalyst regeneration treatment to obtain a second product including regenerated flue gas and regenerated catalyst. The second product enters the second gas-solid separation unit through the outlet of the catalyst regeneration unit for second gas-solid separation to obtain regenerated flue gas and regenerated catalyst. The regenerated flue gas is output from the gas phase outlet of the second gas-solid separation unit, and the regenerated catalyst is fed into the catalyst mixing unit and the petroleum hydrocarbon catalytic cracking unit through the first catalyst outlet and the second catalyst outlet of the second gas-solid separation unit, respectively.

6. The method according to claim 4 or 5, characterized in that, The regenerated catalyst is fed into the catalyst inlet of the catalyst heating unit through the first catalyst outlet of the second gas-solid separation unit to cool down the regenerated catalyst. Part of the cooled regenerated catalyst enters the catalyst mixing unit through the second catalyst inlet of the catalyst mixing unit and is mixed with the stripped catalyst to be regenerated. Part of the cooled regenerated catalyst is returned to the second gas-solid separation unit via the catalyst inlet of the second gas-solid separation unit.

7. The method according to any one of claims 4 to 6, characterized in that, In the stripping unit, a portion of the stripped catalyst to be regenerated enters the catalyst regeneration unit through the second stripped product outlet of the stripping unit, and the remaining portion of the stripped catalyst to be regenerated enters the catalyst mixing unit through the first stripped product outlet of the stripping unit.

8. The method according to any one of claims 4 to 7, characterized in that, The reaction conditions for the first reaction are: a reaction temperature of 480–600℃, a mass ratio of catalyst to petroleum hydrocarbon feedstock of 4–20, a reaction time of 0.5–8 s, and a mass ratio of atomized steam to petroleum hydrocarbon feedstock of 0.02–0.2; and / or, the reaction conditions for the second reaction are: a reaction temperature of 420–520℃, a mass ratio of stripping catalyst to methanol feedstock of 10–100, a reaction time of 0.5–10 s, and a mass ratio of water to methanol in the methanol feedstock of 0–1.

9. The method according to any one of claims 4 to 8, characterized in that, The mass ratio of methanol feedstock entering the methanol-to-olefins unit to petroleum hydrocarbon feedstock entering the petroleum hydrocarbon catalytic cracking unit is 0.01 to 3.

10. The method according to any one of claims 5 to 9, characterized in that, The mass ratio of the regenerated catalyst entering through the second catalyst inlet of the catalyst mixing unit to the stripped catalyst to be regenerated entering through the first catalyst inlet of the catalyst mixing unit is (0-10):(0-10); and / or, the mass ratio of the stripped catalyst to be regenerated entering the catalyst mixing unit from the stripping unit to the stripped catalyst to be regenerated entering the catalyst regeneration unit from the stripping unit is (2-10):(0-8); and / or, the mass ratio of the cooled regenerated catalyst entering the catalyst mixing unit from the catalyst heating unit to the cooled regenerated catalyst entering the second gas-solid separation unit from the catalyst heating unit is (0-10):(0-10).

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