Catalytic cracking method for increasing yield of low-carbon olefins

Abstract

The invention relates to a catalytic cracking method for increasing the yield of low-carbon olefins, which comprises the following steps of: introducing a mixed catalyst consisting of a catalytic cracking catalyst before reaction and inert solid particles before reaction into a reactor to be in contact with a hydrocarbon oil raw material to carry out catalytic cracking reaction, and then carrying out gas-solid separation, an oil gas product and a mixed material flow of the reacted mixed catalyst are obtained; the temperature of the catalytic cracking catalyst before the reaction and the temperature of the inert solid particles before the reaction are above 650 DEG C; the specific heat capacity of the inert solid particles is 1.1-2.5 J / (g.K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 20-100 DEG C. The inert solid particles with high specific heat capacity are introduced into the reaction zone to supplement heat for catalytic cracking of the light raw material, so that the influence of temperature drop on the cracking reaction process of the light raw material is weakened, the yield of low-carbon olefin is increased, and particularly the yield of ethylene and propylene in the product is increased.

Description

Technical Field

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

[0002] As the market demand for light olefins increases, the raw materials for producing light olefins are gradually diversified, and catalytic cracking has become an important technical means to increase the production of light olefins. Catalytic cracking reaction is a strong endothermic process. The conventional catalytic cracking reaction heat is about 180-300 kJ / kg of crude oil, while the catalytic cracking technology for producing light olefins, such as deep catalytic cracking process (DCC) and catalytic thermal cracking process (CPP), has a greater demand for heat, and the cracking reaction heat can reach 600-800 kJ / kg of raw material. In particular, when using raw materials such as naphtha and olefins with a carbon number not higher than 12 to produce light olefins, the heat demand is even higher.

[0003] In order to meet the reaction heat of catalytic cracking, a common method is to use a higher catalyst-to-oil ratio, but this also increases the coke and dry gas yields. In the actual production process, the heat carried by the regeneration process of the spent catalyst is brought to the reactor to heat the feedstock and provide cracking reaction heat. As the reaction proceeds, the temperature of the catalyst decreases to the optimal temperature required for feedstock conversion. If the reaction temperature during the regeneration of the spent catalyst is increased, the temperature of the catalyst at the initial stage of the contact reaction with the feedstock will be higher than the optimal temperature, resulting in an increase in by-products. Therefore, it is crucial that the catalyst is at the optimal temperature for feedstock conversion when it contacts the feedstock.

[0004] In this regard, CN107868675A proposes a catalytic cracking method using a mixture of silicon oxide, titanium oxide and aluminum oxide as a heat carrier, and reduces the consumption of catalytic cracking catalyst by replacing part of the catalytic cracking catalyst with an inert carrier. US6558530B2 discloses a method of gasifying the raw material before introducing it into the reactor, which can reduce the coke deposited on the catalyst and reduce the contact time between the catalyst and the raw material.

[0005] However, there is still a need to further improve the yield of light olefins when producing light olefins by catalytic cracking of olefin-containing feedstocks. Summary of the invention

[0006] The purpose of the present invention is to further increase the yield of light olefins and reduce the yield of dry gas.

[0007] In order to achieve the above-mentioned object, the present invention provides a catalytic cracking method for increasing the production of light olefins, which method comprises the following steps: introducing a mixed catalyst composed of a catalytic cracking catalyst before the reaction and inert solid particles before the reaction into a reactor to contact with a hydrocarbon oil feedstock for a catalytic cracking reaction, and then performing gas-solid separation to obtain a mixed flow of oil and gas products and the mixed catalyst after the reaction; the temperature of the catalytic cracking catalyst before the reaction and the inert solid particles before the reaction are above 650°C; the specific heat capacity of the inert solid particles is 1.1-2.5 J / (g·K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 20-100°C.

[0008] Optionally, the temperature of the catalytic cracking catalyst before the reaction and the inert solid particles before the reaction are above 680°C; the specific heat capacity of the inert solid particles is 1.2-2.0 J / (g·K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 30-90°C.

[0009] Optionally, the conditions of the catalytic cracking reaction include: a reaction temperature of 580-800°C, preferably 600-720°C; a reaction time of 0.1-80 seconds, preferably 0.5-70 seconds; a weight ratio of the mixed catalyst to the hydrocarbon oil feedstock of (3-180):1, preferably (10-150):1.

[0010] Optionally, the hydrocarbon oil feedstock is preheated and gasified to 100-400°C and then introduced into the reactor to contact with the mixed catalyst for reaction; the hydrocarbon oil feedstock is C4-C8 olefin or a mixture containing C4-C8 olefin; the olefin content in the hydrocarbon oil feedstock is 50-100% by weight, preferably 80-100% by weight.

[0011] Optionally, the oil and gas products and the mixed catalyst after the reaction are rapidly cooled to below 530° C. before gas-solid separation.

[0012] Optionally, the mass ratio of the catalytic cracking catalyst to the inert particles is 1:(0.1-3), preferably 1:(0.5-2).

[0013] Optionally, the inert solid particles are microspherical; the particle size of the inert solid particles does not exceed 500 μm, preferably does not exceed 400 μm; the screening composition of the inert solid particles is consistent with the catalytic cracking catalyst; preferably, the inert solid particles include at least one of silicon dioxide, titanium dioxide, aluminum oxide, silicon carbide, aluminum nitride, boron nitride, manganese oxide and boron oxide; preferably, based on the total weight of the inert solid particles, the inert solid particles include 35-55 weight% of silicon dioxide, 5-15 weight% of titanium dioxide, 25-35 weight% of aluminum oxide, 1-15% of manganese oxide and 10-25 weight% of boron nitride.

[0014] Optionally, based on the total weight of the catalytic cracking catalyst, the catalytic cracking catalyst comprises 1-50 wt% of medium-pore zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay; the medium-pore zeolite is selected from at least one of ZSM-5 series zeolites and ZRP zeolites; the inorganic oxide is selected from one or more of silicon dioxide and aluminum oxide; the clay is selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

[0015] Optionally, the method further comprises the following steps: regenerating the mixed catalyst after the reaction by contacting it with an oxygen-containing gas, and then returning the regenerated mixed catalyst to the reactor to participate in the reaction after supplementing heat through fuel combustion.

[0016] Optionally, the reactor is selected from one or two of a riser reactor, a constant linear velocity fluidized bed, a constant diameter fluidized bed, an upward conveying line and a downward conveying line, and a combination of two or more thereof; wherein the riser reactor is a constant diameter riser reactor or a variable diameter fluidized bed reactor.

[0017] Optionally, the reactor is a variable diameter fluidized bed reactor and the reactor includes a first reaction zone and a second reaction zone, the inert solid particles before the reaction are mixed with the catalytic cracking catalyst before the reaction and then introduced into the reactor, or the inert solid particles before the reaction are introduced into the reactor through the side of the first reaction zone and / or the second reaction zone.

[0018] Through the above technical scheme, the present invention, on the basis of using a high-temperature catalyst, introduces inert solid particles with high specific heat capacity into the reaction zone to supplement heat for the catalytic cracking of light raw materials, which can significantly inhibit the phenomenon of a significant drop in the temperature of the catalytic cracking catalyst during the catalytic cracking reaction, weaken the influence of the temperature drop on the cracking reaction process of the light raw materials, promote the single-molecule cracking of the raw materials, and increase the yield of light olefins, especially the yield of ethylene and propylene in the product.

[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 specific embodiments, 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 It is a schematic flow diagram of a catalytic cracking method according to an embodiment of the present invention.

[0022] Description of Reference Numerals

[0023] 1 Pipeline 2 Riser Reactor 3 Pipeline

[0024] 4 pipeline 5 pipeline 6 pipeline

[0025] 7 Outlet section 8 Settler 9 Gas collecting chamber

[0026] 10 Stripping section 11 Pipeline 12 Waiting for production inclined pipe

[0027] 13 Regenerator 14 Pipeline 15 Cyclone separation system

[0028] 16 Pipeline 17 Energy recovery system 18 Heat collector

[0029] 19 Regeneration inclined tube 20 Large oil and gas pipeline 21 Product fractionation device DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0031] In order to achieve the above-mentioned object, the present invention provides a catalytic cracking method for increasing the production of light olefins, which method comprises the following steps: introducing a mixed catalyst composed of a catalytic cracking catalyst before the reaction and inert solid particles before the reaction into a reactor to contact with a hydrocarbon oil feedstock for a catalytic cracking reaction, and then performing gas-solid separation to obtain a mixed flow of oil and gas products and the mixed catalyst after the reaction; the temperature of the catalytic cracking catalyst before the reaction and the inert solid particles before the reaction are above 650°C; the specific heat capacity of the inert solid particles is 1.1-2.5 J / (g·K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 20-100°C.

[0032] The present invention introduces inert solid particles with high specific heat capacity into the reaction zone, which can significantly inhibit the phenomenon of a significant drop in the temperature of the catalytic cracking catalyst during the catalytic cracking reaction, weaken the influence of the temperature drop on the cracking reaction process of light raw materials, promote the single-molecule cracking of the raw materials, and increase the yield of light olefins, especially the yield of ethylene and propylene in the product.

[0033] The temperature of the catalytic cracking catalyst before the reaction and the inert solid particles before the reaction are above 680°C; the specific heat capacity of the inert solid particles is 1.2-2.0 J / (g·K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 30-90°C. Since the inert solid particles provided by the present invention have a high specific heat capacity, the amount of the catalytic cracking catalyst can be reduced while satisfying the heat required by the reaction system and the product yield.

[0034] Wherein, the conditions of the catalytic cracking reaction include: reaction temperature of 580-800°C, preferably 600-720°C; reaction time of 0.1-80 seconds, preferably 0.5-70 seconds; weight ratio of the mixed catalyst to the hydrocarbon oil feedstock of (3-180):1, preferably (10-150); preferably, the hydrocarbon oil feedstock is C4-C8 olefin or a mixture containing C4-C8 olefin; the olefin content in the hydrocarbon oil feedstock is 50-100% by weight, preferably 80-100% by weight.

[0035] The raw materials are first preheated and gasified before being introduced into the reactor to contact with the mixed catalyst, and the preheating temperature is 100-400°C.

[0036] The oil and gas products and the mixed catalyst after the reaction are rapidly cooled to below 530° C. before gas-solid separation.

[0037] The mass ratio of the catalytic cracking catalyst to the inert solid particles is 1:(0.1-3), preferably 1:(0.5-2). The inert solid particles have a high specific heat capacity and will not have an adverse effect on the catalytic cracking reaction process. By adjusting the mass ratio of the inert solid particles to the catalytic cracking catalyst, the reaction heat requirements of different raw materials can be met, making the catalytic cracking process more flexible.

[0038] The inert solid particles are microspheres; the particle size of the inert solid particles does not exceed 500 μm, preferably does not exceed 400 μm. In a specific embodiment of the present invention, for a fixed feedstock composition, the inert solid particles are preferably consistent with the sieve composition of the catalytic cracking catalyst to facilitate heat transfer.

[0039] In a more preferred embodiment of the present invention, the inert solid particles can be prepared into particles smaller or larger than the catalyst particle size for easy separation, and the amount of the inert solid particles can be increased or decreased to adapt to different raw materials.

[0040] Wherein, the inert solid particles include at least one of silicon dioxide, titanium dioxide, aluminum oxide, silicon carbide, aluminum nitride, boron nitride, manganese oxide and boron oxide.

[0041] In a preferred embodiment of the present invention, based on the total weight of the inert solid particles, the inert solid particles include 35-55 wt% silicon dioxide, 5-15 wt% titanium dioxide, 25-35 wt% aluminum oxide, 1-15 wt% manganese oxide and 10-25 wt% boron nitride.

[0042] Wherein, based on the total weight of the catalytic cracking catalyst, the catalytic cracking catalyst comprises 1-50 wt% of medium-pore zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay; the medium-pore zeolite is selected from at least one of ZSM-5 series zeolite and ZRP zeolite; the inorganic oxide is selected from one or more of silicon dioxide and aluminum oxide; the clay is selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

[0043] The method further comprises the following steps: regenerating the mixed catalyst after the reaction by contacting it with an oxygen-containing gas, and then returning the regenerated mixed catalyst to the reactor to participate in the reaction after fuel combustion to supplement heat.

[0044] The reactor is selected from one or two of a riser reactor, a constant linear velocity fluidized bed, a constant diameter fluidized bed, an upward conveying line and a downward conveying line, and a combination of two or more thereof; wherein the riser reactor is a constant diameter riser reactor or a variable diameter fluidized bed reactor.

[0045] Wherein, the reactor is a variable diameter fluidized bed reactor and the reactor includes a first reaction zone and a second reaction zone, the inert solid particles before the reaction are mixed with the catalytic cracking catalyst before the reaction and then introduced into the reactor, or the inert solid particles before the reaction are introduced into the reactor through the side of the first reaction zone and / or the second reaction zone.

[0046] In the present invention, the inert solid particles before the reaction can be introduced into the reactor after being uniformly mixed with the catalytic cracking catalyst before the reaction, or can be introduced into the reactor separately from the catalytic cracking catalyst before the reaction, for example, the inert solid particles before the reaction are introduced into the reactor from a specific position of the reactor. The proportion of the inert solid particles before the reaction can also be adjusted as needed to strengthen the heat supply to the raw material during the reaction process and reduce the temperature drop.

[0047] For example, in one specific embodiment of the present invention, the reactor is a multi-zone reactor, such as a variable diameter fluidized bed reactor, and the inert solid particles before the reaction are introduced into the first reaction zone or the second reaction zone through a pipeline on the side of the reactor, or are introduced into the first reaction zone and the second reaction zone respectively.

[0048] Figure 1 FIG. 1 is a schematic flow diagram of a catalytic cracking method according to an embodiment of the present invention, as shown in FIG. Figure 1 As shown, the pre-lifting medium from pipeline 1 enters from the bottom of the riser reactor 2, and the mixed catalyst composed of the catalytic cracking catalyst and the inert solid particles before the reaction from the regeneration inclined tube 19 moves upward under the action of the pre-lifting medium. The preheated hydrocarbon oil feedstock from pipeline 3 and the atomized steam from pipeline 4 are injected into the bottom of the riser reactor 2 together, contact with the catalytic cracking catalyst to produce a catalytic cracking reaction and move upward along the reactor. The mixture of catalytic cracking oil and gas products and the mixed catalyst after the reaction flows through the outlet section 7 of the riser reactor 2 and enters the cyclone separator of the settler 8 to separate the mixed catalyst after the reaction and the oil and gas products. The separated oil and gas products enter the gas collecting chamber 9, and the reacted oil and gas in the gas collecting chamber 9 enter the subsequent product fractionation device 21 through the large oil and gas pipeline 20.

[0049] The mixed catalyst after the reaction returns from the feed leg to the settler 8 and enters the stripping section 10, where it is stripped by the stripping medium from the pipeline 11 to remove the adsorbed reaction oil gas, and then enters the regenerator 13 through the regenerated inclined pipe 12 to contact with the oxygen-containing gas from the pipeline 14 to burn off the coke carried on the catalyst. The regenerated catalyst, inert solid particles and flue gas after the coking enter the cyclone separator 15 for separation, and the separated flue gas enters the flue gas energy recovery system 17 through the pipeline 16 to recover energy. The regenerated catalyst and inert solid particles return to the bottom of the regenerator 13 and are supplemented with heat by the heat collector 18, and then return to the pre-lift tube reactor 2 through the regeneration inclined pipe 19.

[0050] In another embodiment of the present invention, the reactor is a variable diameter fluidized bed reactor, for example, the reactor 2 includes a first reaction zone I and a second reaction zone II, and the inert solid particles can be introduced into the reactor through the side of the first reaction zone or the second reaction zone. For example, the inert solid particles from pipeline 5 enter the second reaction zone under the action of the medium from pipeline 6 and mix with the catalyst to supplement heat for the reaction system.

[0051] The present invention is further described in detail by way of examples below, but the present invention is not limited thereto. The raw materials used in the examples can be obtained through commercial sources. Among them, the raw material used in the examples and comparative examples is 1-pentene.

[0052] Halloysite is an industrial product of China Kaolin Corporation, with a solid content of 73%.

[0053] Pseudo-boehmite is produced by Shandong Zibo Bauxite Factory and has a solid content of 64%.

[0054] The preparation method and properties of the catalyst used in the examples are as follows:

[0055] 969 g of halloysite was weighed and slurried in 4300 g of decationized water. 781 g of pseudo-boehmite and 144 mL of hydrochloric acid (concentration 30% by weight, specific gravity 1.56) were added to the obtained slurry and stirred evenly. The pH was kept at 2-4. After being aged at 60° C. for 1 hour, the slurry was cooled to room temperature. Then, 5000 g of a slurry of a high silicon-aluminum ratio medium-pore shape-selective ZSM-5 zeolite containing chemical water was added to the aged slurry. The slurry was stirred evenly and spray-dried to wash away free Na + After steam aging, the free Na + The catalyst was aged in water vapor at 800°C for 15 h. The properties of the obtained catalyst are shown in Table 1.

[0056] Table 1

[0057]

[0058]

[0059] Example 1

[0060] This embodiment follows Figure 1 The catalytic cracking reaction of light raw materials was tested in a medium-sized device of a riser reactor according to the process shown in the figure. 1-Pentene and a high-temperature mixed catalyst (the weight ratio of catalyst A to inert solid particles is 1:0.2) were contacted in the riser reactor for catalytic cracking reaction. Wherein, based on the total weight of the inert solid particles, the composition of the inert solid particles is: 50 mass% silicon dioxide, 10 mass% titanium dioxide, 30 mass% aluminum oxide and 10 mass% boron nitride.

[0061] The reaction products separated by the cyclone separator are sent to the subsequent product fractionation device, and the mixed catalyst to be regenerated is introduced into the regenerator for char regeneration and then returned to the riser reactor to continue to participate in the reaction.

[0062] The reaction conditions and product distribution are shown in Table 2.

[0063] Example 2

[0064] Example 2 was tested according to the method of Example 1, except that the weight ratio of the catalyst to the inert solid particles was different, wherein the weight ratio of the catalyst A to the inert solid particles was 1:0.5. The reaction conditions and product distribution are shown in Table 2.

[0065] Comparative Example 1

[0066] Comparative Example 1 was tested according to the method of Example 1, except that no inert solid particles were introduced into the reaction system. The reaction conditions and product distribution are shown in Table 2.

[0067] Table 2

[0068]

[0069]

[0070] As shown in Table 2, by introducing a mixed catalyst consisting of inert solid particles with high specific heat capacity and a catalytic cracking catalyst, the phenomenon of a substantial decrease in the temperature of the catalytic cracking catalyst during the catalytic cracking reaction is significantly suppressed, thereby weakening the effect of the temperature drop on the cracking reaction process of light raw materials, improving the single-molecule cracking selectivity of the raw material olefins, and increasing the yields of light olefins and ethylene and propylene in the products, thereby promoting efficient utilization of raw materials.

[0071] The inert solid particles with high specific heat capacity in the mixed catalyst will not have adverse effects on the catalytic cracking reaction process of the raw materials, and the composition of the catalytic cracking catalyst does not need to be adjusted, so the operation is more flexible.

[0072] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0073] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0074] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A catalytic cracking method for increasing the production of light olefins, characterized in that: The method comprises the following steps: A mixed catalyst consisting of a catalytic cracking catalyst before the reaction and inert solid particles before the reaction is introduced into a reactor to contact with a hydrocarbon oil feedstock for a catalytic cracking reaction, and then a gas-solid separation is performed to obtain a mixed flow of oil and gas products and the mixed catalyst after the reaction; the temperature of the catalytic cracking catalyst before the reaction and the inert solid particles before the reaction are above 650°C; the specific heat capacity of the inert solid particles is 1.1-2.5 J / (g·K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 20-100°C.

2. The method according to claim 1, wherein: The temperature of the catalytic cracking catalyst and the inert solid particles before the reaction is above 680°C; the specific heat capacity of the inert solid particles is 1.2-2.0 J / (g·K); the difference between the temperature of the mixed catalyst after the reaction and the temperature of the mixed catalyst before the reaction is 30-90°C.

3. The method according to claim 1, wherein: The conditions of the catalytic cracking reaction include: a reaction temperature of 580-800°C, preferably 600-720°C; The reaction time is 0.1-80 seconds, preferably 0.5-70 seconds; The weight ratio of the mixed catalyst to the hydrocarbon oil feedstock is (3-180):1, preferably (10-150):

1.

4. The method according to claim 1, wherein: The hydrocarbon oil feedstock is preheated and gasified to 100-400° C. and then introduced into the reactor to contact with the mixed catalyst for reaction; The hydrocarbon oil feedstock is C4-C8 olefin or a mixture containing C4-C8 olefin; the content of olefin in the hydrocarbon oil feedstock is 50-100% by weight, preferably 80-100% by weight.

5. The method according to claim 1, wherein: The oil and gas products and the mixed catalyst after the reaction are rapidly cooled to below 530° C. before gas-solid separation.

6. The method according to claim 1, wherein: The mass ratio of the catalytic cracking catalyst to the inert solid particles is 1:(0.1-3), preferably 1:(0.5-2).

7. The method according to claim 1, wherein: The inert solid particles are microspherical; the particle size of the inert solid particles is not higher than 500 μm, preferably not higher than 400 μm; The inert solid particles have a consistent sieve composition with that of the catalytic cracking catalyst; The inert solid particles include at least one of silicon dioxide, titanium dioxide, aluminum oxide, silicon carbide, aluminum nitride, boron nitride, manganese oxide and boron oxide; Preferably, based on the total weight of the inert solid particles, the inert solid particles include 35-55 wt% silicon dioxide, 5-15 wt% titanium dioxide, 25-35 wt% aluminum oxide, 1-15 wt% manganese oxide and 10-25 wt% boron nitride.

8. The method according to claim 1, wherein: Based on the total weight of the catalytic cracking catalyst, the catalytic cracking catalyst comprises 1-50 wt% of medium-pore zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay; The medium-pore zeolite is selected from at least one of ZSM-5 series zeolites and ZRP zeolites; The inorganic oxide is selected from one or more of silicon dioxide and aluminum oxide; The clay is selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, saponite, rectorite, sepiolite, attapulgite, hydrotalcite and bentonite.

9. The method according to claim 1, wherein: The method further comprises the following steps: The mixed catalyst after the reaction is contacted with oxygen-containing gas for regeneration, and then the regenerated mixed catalyst is returned to the reactor to participate in the reaction after fuel combustion to supplement heat.

10. The method according to claim 1, wherein: The reactor is selected from one or two of a riser reactor, a constant linear velocity fluidized bed, a constant diameter fluidized bed, an upward conveying line and a downward conveying line, or a combination of two or more thereof; wherein the riser reactor is a constant diameter riser reactor or a variable diameter fluidized bed reactor; Preferably, the reactor is a variable diameter fluidized bed reactor and the reactor comprises a first reaction zone and a second reaction zone, and the inert solid particles before the reaction are mixed with the catalytic cracking catalyst before the reaction and then introduced into the reactor, or The inert solid particles before the reaction are introduced into the reactor through the side of the first reaction zone and / or the second reaction zone.

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