A catalytic cracking regeneration device and a catalytic cracking regeneration method for producing carbon monoxide

Abstract

The application discloses a catalytic cracking regeneration device and a catalytic cracking regeneration method for generating carbon monoxide, the device is connected with a pre-lifting pipe through a coking tank, so that the spent catalyst and oxygen are rapidly mixed and contacted in the pre-lifting pipe, the gas-solid mass transfer between the spent catalyst and the oxygen is improved, the spent catalyst is rapidly ignited and heated, and the first regenerator is located in the nested two-stage regeneration type structure of the second regenerator, so that the heat generated in the coking process of the second regenerator is fully utilized to further promote the combustion of coke and the chemical conversion of CO2 in the partial regeneration process of the catalyst in the coking tank, and then high-concentration carbon monoxide is generated as a chemical raw material (the content of CO in the first flue gas separated by the first cyclone separator is more than 50 v%), so that certain economic benefits can be obtained; in addition, the resource utilization of carbon dioxide is also promoted to a certain extent, and the effect of carbon emission reduction is achieved.

Description

Technical Field

[0001] This invention relates to the field of catalyst regeneration technology, and particularly to a catalytic cracking regeneration device and a catalytic cracking regeneration method that produces more carbon monoxide. Background Technology

[0002] Catalytic cracking, as the most important secondary processing method in my country's petroleum refining industry, accounts for 70% of the country's gasoline, 35% of its diesel, and 40% of its propylene production. It is a crucial means of heavy oil processing and holds a pivotal position in my country's refining industry. The coke regeneration process in catalytic cracking units generates a large amount of carbon dioxide. Domestic catalytic cracking units emit approximately 50 million tons of carbon dioxide annually, making it the largest single source of carbon emissions from refineries and significantly impacting the environment. Simultaneously, the regeneration flue gas also contains some carbon monoxide, which is typically recovered industrially through direct combustion in a carbon monoxide combustion furnace. Carbon monoxide can be used as a chemical feedstock to produce low-carbon alkanes, low-carbon olefins, alcohols, and esters. Capturing and utilizing carbon monoxide in the regeneration flue gas can generate considerable economic benefits and is also a technological pathway for achieving carbon emission reduction in catalytic cracking units.

[0003] However, the concentration of carbon monoxide in regenerated flue gas is relatively low, generally not exceeding 5% (v%). If carbon monoxide combustion aids are used during the regeneration process, the carbon monoxide concentration in the flue gas will be further reduced. Directly capturing and utilizing carbon monoxide from traditional catalytic cracking flue gas is energy-intensive and impractical. Higher carbon monoxide concentrations usually mean lower carbon monoxide capture costs, making carbon monoxide capture more practical. However, in traditional catalytic cracking regeneration processes, a certain amount of excess oxygen in the regenerated flue gas is required to maintain coking intensity. If the carbon monoxide concentration in the regenerator is too high, it will significantly increase the possibility of secondary combustion and tail combustion in the flue gas. Secondary combustion involves carbon monoxide burning in the regenerator to produce carbon dioxide, while tail combustion involves carbon monoxide burning in the flue gas duct and chimney to produce carbon dioxide, both of which increase the risk of accidents in the unit. Even if the main component is reduced and a lean oxygen environment is adopted for regeneration, the excess oxygen in the flue gas still needs to be controlled at 0.5%–1% (v%) to meet the overall catalyst regeneration requirements, and the effect on increasing the CO concentration is limited. Therefore, increasing carbon monoxide concentration is difficult under traditional catalytic cracking regeneration process conditions. Studies (Luciana et al., Mechanistic insights of CO2-coke reaction during the regeneration step of the fluid cracking catalyst, Applied Catalysis A: General, Volume 336; Shenyong Li et al., Non-Destructive characterisation of coke deposit on FCC catalyst and its transient evolution upon Air-Firing and Oxy-Fuel regeneration, Chemical Engineering Journal, Volume 430) show that within the normal catalytic cracking regeneration temperature range, the carbon dioxide-coke reaction occurs even in the presence of oxygen. Consequently, coke is consumed more quickly and more carbon monoxide is produced under an oxygen / carbon dioxide atmosphere. Therefore, by using a regeneration gas rich in carbon dioxide and utilizing the large amount of heat energy generated during coke combustion on the catalyst to promote the carbon dioxide-coke reaction within the regenerator, the concentration of carbon monoxide in the flue gas can be increased while the spent catalyst is being regenerated through coking. This allows for the efficient capture of carbon monoxide in the regenerated flue gas, achieving its chemical utilization.

[0004] Chinese patent document CN103725309A discloses a catalyst regeneration method for reducing carbon dioxide emissions. The method involves first partially regenerating the charred catalyst in a coke burner using pure oxygen, then passing it through a dilute phase tube into a dense phase bed in a regeneration unit to burn off the remaining coke. A heat exchanger is installed in the dense phase bed to control its temperature. The flue gas, after being separated by a cyclone separator, sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture the carbon dioxide. The regenerated catalyst is then directly returned to the reactor for recycling. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0005] Chinese patent document CN103721766A discloses a catalyst regeneration method that reduces carbon dioxide emissions and improves selectivity. The method involves first regenerating the charred catalyst in a first regenerator using pure oxygen, then circulating it through an external pipe to a second regenerator located below the first regenerator where the remaining coke is burned off with pure oxygen. The catalyst exiting the first regenerator enters an external heat exchanger, cools, and returns to the second regenerator. Most of the flue gas is separated by a cyclone separator and then sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture carbon dioxide. A small amount of flue gas is recycled to the bottom of the second regenerator. The regenerated catalyst is cooled, activated, and then recycled back into the reactor. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0006] Chinese patent document CN103721763A discloses a catalyst regeneration method that reduces carbon dioxide emissions and improves selectivity. In this method, a char-laden catalyst is first carried upwards in a coke combustion tube by pure oxygen gas, where a coke combustion reaction occurs. The coke combustion ratio in the tube is 30-50%. The catalyst exiting the tube is then subjected to pure oxygen to burn off the remaining coke. The flue gas is then separated by a cyclone separator and sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture carbon dioxide. The regenerated catalyst is cooled and activated before being recycled back into the reactor. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0007] Chinese patent document CN103725311A discloses a catalyst regeneration method to reduce carbon dioxide emissions and improve selectivity. The method involves first regenerating the charred catalyst in a first regenerator using pure oxygen, then feeding it through a U-shaped conveyor into a second regenerator where the remaining coke is burned off with pure oxygen. The flue gas exiting the first regenerator is divided into three parts: the first part is recycled to replenish the bottom of the second regenerator; the second part transfers the semi-regenerated catalyst from the first regenerator to the second regenerator; and the third part enters a flue gas energy recovery system. The flue gas from the second regenerator and the flue gas from the first regenerator, after merging, enter a carbon dioxide separation system where carbon dioxide is separated and captured. The regenerated catalyst, after cooling and activation, is then recycled back into the reactor. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, potentially even achieving zero carbon emissions.

[0008] Chinese patent document CN103721765A discloses a catalyst regeneration method for reducing carbon dioxide emissions. The method involves first regenerating the charred catalyst in a first regenerator using pure oxygen, then circulating it through an external pipe to a second regenerator located below the first regenerator where the remaining coke is burned off with pure oxygen. The catalyst exiting the first regenerator enters an external heat exchanger, cools, and then returns to the second regenerator. The flue gas is separated by a cyclone separator and then sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture carbon dioxide. The regenerated catalyst is directly returned to the reactor for recycling. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0009] Chinese patent document CN103725308A discloses a catalyst regeneration method for reducing carbon dioxide emissions. In this method, a char-laden catalyst is first carried upwards in a coke combustion tube by pure oxygen gas, where a coke combustion reaction occurs. The coke combustion ratio in the tube is 30-50%. The catalyst exiting the tube is then subjected to pure oxygen to burn off the remaining coke. The flue gas is then separated by a cyclone separator and sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture carbon dioxide. The regenerated catalyst is directly returned to the reactor for recycling. This method not only achieves complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0010] Chinese patent document CN103721743A discloses a catalyst regeneration method for reducing carbon dioxide emissions. The method involves first partially regenerating the charred catalyst in a coke burner using pure oxygen, then passing it through a macroporous distribution plate into a dense-phase bed in a regeneration unit to burn off the remaining coke. A heat exchanger is installed in the dense-phase bed to control its temperature. The flue gas is then separated by a cyclone separator and sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture the carbon dioxide. The regenerated catalyst is directly returned to the reactor for recycling. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0011] Chinese patent document CN103725310A discloses a catalyst regeneration method for reducing carbon dioxide emissions. The method involves first regenerating the charred catalyst in a first regenerator using pure oxygen, then feeding it through a U-shaped conveyor into a second regenerator where the remaining coke is burned off with pure oxygen. The flue gas exiting the first regenerator is divided into three parts: the first part is recycled to replenish the bottom of the second regenerator; the second part carries the semi-regenerated catalyst from the first regenerator to the second; and the third part enters a flue gas energy recovery system. The flue gas from the second regenerator and the flue gas from the first regenerator from the flue gas energy recovery system are combined and then enter a carbon dioxide separation system. After carbon dioxide is separated and captured, the regenerated catalyst is directly returned to the reactor for recycling. This method not only achieves complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0012] Chinese patent document CN103721764A discloses a catalyst regeneration method that reduces carbon dioxide emissions and improves selectivity. The method involves first regenerating the charred catalyst in a first regenerator using pure oxygen, then introducing it through a riser into a second regenerator located above the first regenerator where the remaining coke is burned off with pure oxygen. The flue gas exiting the first regenerator is divided into two parts: one part is recycled to the bottom of the second regenerator, and the other part enters a flue gas energy recovery system. The flue gas from the second regenerator and the flue gas from the first regenerator from the flue gas energy recovery system are combined and then enter a carbon dioxide separation system. After carbon dioxide is separated and captured, the regenerated catalyst is cooled, activated, and then recycled back into the reactor. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0013] Chinese patent document CN103721762A discloses a catalyst regeneration method that reduces carbon dioxide emissions and improves selectivity. The method involves first partially regenerating the charred catalyst in a coke burner using pure oxygen, then passing it through a dilute phase tube into a dense phase bed in a regeneration unit to burn off the remaining coke. A heat exchanger is installed in the dense phase bed to control its temperature. The flue gas, after being separated by a cyclone separator, sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture carbon dioxide. The regenerated catalyst, after being cooled and activated, is then recycled back into the reactor. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, potentially even achieving zero carbon emissions.

[0014] Chinese patent document CN103721761A discloses a catalyst regeneration method that reduces carbon dioxide emissions and improves selectivity. The method involves partially regenerating the charred catalyst in a coke burner using pure oxygen, then passing it through a macroporous distribution plate into a dense-phase bed in a regeneration unit to burn off the remaining coke. A heat exchanger is installed in the dense-phase bed to control its temperature. Most of the flue gas is separated by a cyclone separator and then sequentially enters a flue gas energy recovery system and a carbon dioxide separation system to separate and capture carbon dioxide. A small amount of flue gas is recycled to the bottom of the coke burner. The regenerated catalyst, after being cooled and activated, is then recycled back into the reactor. This method not only ensures complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts such as coke and dry gas, but also significantly reduces carbon emissions, potentially even achieving zero carbon emissions.

[0015] Chinese patent document CN103721742A discloses a catalyst regeneration method for reducing carbon dioxide emissions. The carbon-bearing catalyst is first partially regenerated with pure oxygen in a first regenerator, then enters a second regenerator located above the first regenerator via a riser to burn off the remaining coke with pure oxygen. The flue gas exiting the first regenerator is divided into two parts: one part is recycled to the bottom of the second regenerator, and the other part enters a flue gas energy recovery system. The flue gas exiting the second regenerator and the flue gas from the first regenerator from the flue gas energy recovery system are combined and then enter a carbon dioxide separation system. After carbon dioxide is separated and captured, the regenerated catalyst is directly returned to the reactor for recycling. This method not only enables complete catalyst regeneration and a more uniform distribution of catalyst activity, thereby reducing the yield of catalytic cracking byproducts coke and dry gas, but also significantly reduces carbon emissions, even achieving zero carbon emissions.

[0016] However, the technologies disclosed in the aforementioned comparative literature only recycle the carbon dioxide produced during catalyst regeneration into the regenerator, failing to chemically convert the carbon dioxide to produce more carbon monoxide, resulting in a waste of resources. Furthermore, the flue gas from these technologies has a high oxygen content, leading to a large total oxygen consumption, which increases the risk of secondary combustion within the regenerator and also increases the cost of the catalyst regeneration process.

[0017] Chinese patent document CN101497811A describes the following: In at least one embodiment of the present invention, a method for heating an FCC device having a regenerator and a reactor for overall CO2 reduction is provided. The method includes compressing syngas to obtain compressed syngas. A first gas stream containing CO2 is separated from the compressed syngas. A second gas stream containing O2 is expanded with the first gas stream to obtain a feed gas. The feed gas is introduced into a regenerator, which, under gasification conditions, burns coke from a heavily coked waste catalyst from the reactor, thereby generating syngas and heat for operating the reactor at the reaction temperature.

[0018] Chinese patent document CN101538475A describes the following: In at least one embodiment of the present invention, a method for heating a fluidized catalytic cracking unit having a reactor and a regenerator for overall carbon dioxide reduction is provided. The method includes compressing syngas to obtain compressed syngas. CO2 is separated from the compressed syngas to provide a first gas stream containing CO2. The first gas stream is expanded with a second gas stream containing O2 to obtain a feed gas. The feed gas and injected hydrocarbon feed are introduced into a regenerator containing spent catalyst from the reactor. The regenerator combusts the injected hydrocarbon feed and coke from the spent catalyst under gasification conditions, thereby producing syngas and heat for operating the reactor at the reaction temperature.

[0019] Both of the aforementioned comparative studies require injecting solvent into the regenerator to reheat the asphalt combustion in the deasphalting unit. However, the high heavy metal content in asphalt can easily lead to catalyst deactivation due to heavy metal contamination. Furthermore, uneven asphalt distribution can cause localized overheating of the catalyst during combustion, which can also damage catalyst activity.

[0020] Chinese patent document CN202210478668.1 discloses a method for regenerating spent catalyst in catalytic cracking, relating to the field of petrochemical technology. The method involves first regenerating the spent catalyst in a first regenerator with oxygen deficiency, and then regenerating it in a second regenerator with oxygen enrichment. The main airflow in both regenerators is primarily recirculated flue gas and oxygen, replacing the traditional air (a mixture of oxygen and nitrogen) as the main airflow in the regenerators. This promotes the coking regeneration of the regenerator, and the carbon monoxide content in the flue gas generated in the first regenerator can reach over 30%, significantly reducing the cost of carbon monoxide separation and purification. However, this method uses an oxygen-enriched regeneration atmosphere in the second regenerator, resulting in a high oxygen consumption. Furthermore, the first regenerator fails to chemically convert the carbon dioxide produced during the regeneration process to generate more carbon monoxide, resulting in a carbon monoxide concentration in the flue gas of only 30%, and the cost of carbon monoxide purification and separation remains high.

[0021] Chinese patent document CN105521832B discloses a method for regenerating a catalytic cracking catalyst. The method includes the following steps: (1) introducing the unregenerated catalyst into a first regenerator, where it is contacted with a first oxygen-containing gas for coking regeneration to obtain a semi-regenerated catalyst; (2) introducing the semi-regenerated catalyst into a second regenerator, where it is contacted with a second oxygen-containing gas in the dense phase region of the catalyst in the second regenerator for further coking regeneration, and the gas generated after coking is contacted with methanol for continued combustion. The equipment includes a first regenerator and a second regenerator, each having a dense phase region and a dilute phase region. The dense phase regions of the first and second regenerators are connected by a conduit, and a methanol distributor is installed inside the second regenerator. This method can significantly reduce the temperature of the dilute phase bed of the catalyst in the regenerator, enabling stable operation of the regenerator and improving the product distribution of the catalytic cracking process.

[0022] Chinese patent document CN1221022A discloses an overlapping two-stage regeneration method for coking catalysts in fluidized catalytic cracking of heavy oil and / or residue oil. The method includes two regenerators arranged in an overlapping manner, with the first-stage regeneration on top and the second-stage regeneration on the bottom. The two regenerators are connected by a low-pressure drop distribution plate. The second-stage regeneration flue gas, which contains a certain amount of excess oxygen, is fully utilized as the combustion gas for the first-stage regeneration, thereby saving the amount of oxygen-containing gas used, which saves energy and production costs. Moreover, the two regenerators only require one flue and one double-acting slide valve or butterfly valve, which is simple in structure and easy to control. At the same time, the reduced equipment, compact layout, and small footprint reduce construction investment.

[0023] However, the regenerators mentioned in the two comparative studies are traditional high-low parallel dual regenerators. The purpose of this regeneration method is to improve the coking efficiency of the regenerator. Generally, the carbon monoxide concentration in the regenerated flue gas will not exceed 5%, so it is not possible to produce more carbon monoxide. Summary of the Invention

[0024] The purpose of this invention is to provide a catalytic cracking regeneration device and a catalytic cracking regeneration method that produces more carbon monoxide. Using this device to regenerate the catalytic cracking catalyst can promote the resource utilization of carbon dioxide, increase the carbon monoxide content in flue gas, and reduce the purification and separation cost of carbon monoxide.

[0025] To achieve the above objectives, the present invention provides a catalytic cracking regeneration device, wherein the catalytic cracking regeneration device is a nested two-stage regeneration structure, and the first regenerator is located inside the second regenerator;

[0026] The first regenerator includes a coke burner and a pre-lift pipe. The bottom of the coke burner is provided with a main air distributor for conveying the second regeneration gas. One end of the pre-lift pipe passes through the main air distributor. The other end of the pre-lift pipe is provided with a first regeneration gas inlet and extends to the bottom outer side of the second regenerator. The side wall of the pre-lift pipe on the bottom outer side of the second regenerator is provided with a catalyst inlet. The top of the coke burner is connected to the first cyclone separator.

[0027] The second regenerator has a third regeneration gas inlet at the bottom, a second flue gas outlet at the top, a regeneration catalyst outlet on the bottom side, and a first flue gas outlet on the top side, which is connected to the first cyclone separator; a second cyclone separator is located at the top inside, and the second cyclone separator is connected to the second flue gas outlet.

[0028] In the catalytic cracking regeneration device provided by this invention, the coking catalyst from the stripping section of the catalytic cracking unit is fed into the coke burner by the first regeneration gas input through the first regeneration gas inlet and then transported upward through the pre-lift pipe. It undergoes a pre-combustion reaction within the pre-lift pipe. After entering the coke burner, it mixes with the second regeneration gas supplied by the main air distributor at the bottom of the coke burner for combustion. The semi-regenerated catalyst exiting from the top of the coke burner undergoes gas-solid separation through the first cyclone separator to obtain first flue gas and semi-regenerated catalyst. The first flue gas is led out of the regeneration device through a separate pipeline, and carbon monoxide is captured as a chemical raw material. The semi-regenerated catalyst is introduced into the second regenerator through the feed leg of the first cyclone separator and mixed with the third regeneration gas input through the third regeneration gas inlet at the bottom of the second regenerator for combustion. This allows the incompletely regenerated catalyst to further react and be completely regenerated in the catalyst bed of the second regenerator.

[0029] Optionally, the location of the material leg outlet of the first cyclone separator is not specifically limited, but preferably the material leg outlet of the first cyclone separator is located in the dense phase section of the second regenerator.

[0030] Optionally, the first regenerator is located in the middle region of the second regenerator in a horizontal position; preferably, the coking tank is located in the dilute phase region of the second regenerator.

[0031] Optionally, the inner diameter ratio of the coke burner to the pre-lifting tube is (4-6):1, and the inner diameter ratio of the dense phase section of the second regenerator to the coke burner is (1.5-2):1. By limiting the inner diameter ratio, it is ensured that the fluidization of the catalyst in the second regenerator is less affected by the built-in coke burner.

[0032] Optionally, the first regenerator is made of a thermally conductive and wear-resistant composite material, including manganese alloy steel, chromium cast iron, and carbon steel.

[0033] Optionally, the second regenerator is provided with at least one heat exchanger. The purpose of the heat exchanger is to control the temperature of the bed inside the second regenerator. The location of the heat exchanger can be adjusted according to actual needs, such as being located inside or outside the second regenerator.

[0034] Optionally, the catalytic cracking regeneration unit is connected to the catalytic cracking reactor through the unused catalyst inlet and the regenerated catalyst outlet: the regenerated catalyst discharged from the regenerated catalyst outlet of the second regenerator is returned to the catalytic cracking reactor to participate in the catalytic cracking reaction; the unused catalyst discharged from the catalytic cracking reactor enters the catalytic cracking regeneration unit through the unused catalyst inlet for regeneration, thereby realizing the continuous operation of the catalytic cracking reaction and catalyst regeneration.

[0035] The present invention also provides a catalytic cracking regeneration method for producing more carbon monoxide, using the above-mentioned catalytic cracking regeneration apparatus, comprising the following steps:

[0036] The catalyst to be generated is pre-combusted with the first regeneration gas in the pre-lift pipe and then conveyed upward to the coke burner to be mixed with the second regeneration gas supplemented by the main air distributor at the bottom of the coke burner for partial regeneration reaction, and the coke burning ratio of the first regenerator is controlled to be 20%-50%.

[0037] The material discharged from the coke oven is separated into first flue gas and semi-regenerated catalyst by the first cyclone separator; the first flue gas is discharged through the first flue gas outlet; the semi-regenerated catalyst is conveyed to the dense phase section of the second regenerator by the material leg of the first cyclone separator to undergo a regeneration reaction with the third regeneration gas, and the coke ratio of the second regenerator is controlled to be 50%-80%.

[0038] Wherein, the first regenerated gas is oxygen; the second regenerated gas is carbon dioxide, or a mixture of carbon dioxide and oxygen; and the third regenerated gas is an oxygen-containing gas.

[0039] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the gas concentration of the first regeneration gas (oxygen) input from the first regeneration gas inlet is greater than 99v%.

[0040] The carbon dioxide concentration used in the second regenerated gas input from the main air distributor is greater than 99%;

[0041] The third regeneration gas input from the third regeneration gas inlet is carbon dioxide and / or a mixture of nitrogen and oxygen (a mixture of carbon dioxide and oxygen, a mixture of nitrogen and oxygen, or a mixture of carbon dioxide, nitrogen and oxygen), or air.

[0042] The sources of carbon dioxide include carbon dioxide captured by other processes, and the sources of oxygen include oxygen produced by air separation units and oxygen produced as a byproduct of water electrolysis for hydrogen production.

[0043] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the oxygen concentration of the regeneration gas in the coke burner is not higher than 10% (v), preferably not higher than 8% (v).

[0044] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the oxygen concentration of the regeneration gas in the second regenerator is 18v%-30v%, preferably 21v%-25v.

[0045] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the first regenerator is operated in a fast fluidized bed; the second regenerator is operated in a bubbling bed or a turbulent bed.

[0046] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the amount of catalyst in the first regenerator accounts for 20%-30% of the total capacity of the first regenerator.

[0047] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the operating conditions of the first regenerator are as follows: the regeneration temperature is 700-850℃, preferably 720-820℃; the apparent linear velocity of the gas in the pre-lift pipe is 8-10 m / s; the average residence time of the catalyst in the coke burner is 2.0-4.0 min, preferably 2.5-3.5 min, and the apparent linear velocity of the gas in the coke burner is 1-3 m / s.

[0048] Optionally, in the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention, the operating conditions of the second regenerator are as follows: regeneration temperature 650-820℃, preferably 670-800℃; average residence time of catalyst in the second regenerator 5.0-15.0 min, preferably 8.0-12.0 min; apparent linear velocity of gas in the second regenerator 0.3-0.9 m / s, preferably 0.4-0.8 m / s.

[0049] Optionally, the catalytic cracking regeneration method for producing more carbon monoxide provided by the present invention is applicable to the regeneration of any conventional catalytic cracking catalyst. For example, a catalyst comprising zeolite, inorganic oxides and clay can be used for regeneration. Based on the total weight of the catalyst (100%), the zeolite content is 2wt%-55wt%, the inorganic oxide content is 4wt%-97wt%, and the clay content is 1wt%-75wt%.

[0050] Optionally, among the catalysts listed above in this invention, preferably, the zeolite is modified with Group IA metal elements (alkali metals, such as lithium, sodium, potassium, rubidium, cesium, francium) and / or Group IIA metal elements (alkaline earth metals, such as beryllium, magnesium, calcium, strontium, barium, radium). The modification can be carried out using conventional methods in the industry, and will not be elaborated here.

[0051] Optionally, in the catalysts listed above in this invention, the zeolite includes mesoporous zeolite and macroporous zeolite, wherein the mesoporous zeolite accounts for 5wt%-100wt% of the total weight of the zeolite, preferably 10wt%-80wt%, and the macroporous zeolite accounts for 0wt%-90wt% of the total weight of the zeolite, preferably 10wt%-80wt%.

[0052] Optionally, in the catalysts listed above in this invention, the mesoporous zeolite is selected from one or more of the ZSM series zeolites, or ZRP zeolite;

[0053] The inorganic oxide is selected from silicon dioxide and / or aluminum oxide;

[0054] The clay is selected from one or more of the following: kaolin, montmorillonite, diatomite, soapstone, palygorskite, sepiolite, hydrotalcite, and bentonite.

[0055] Compared with the prior art, the present invention has the following advantages:

[0056] Beneficial Effect 1: The catalytic cracking regeneration device provided by this invention, by connecting the coking tank and the pre-lift pipe, allows the spent catalyst and oxygen to mix and contact rapidly in the pre-lift pipe, which can improve the gas-solid mass transfer between the spent catalyst and oxygen, and achieve rapid ignition and heating of the spent catalyst. Furthermore, the nested two-stage regeneration structure, with the first regenerator located inside the second regenerator, can fully utilize the heat generated during the coking process in the second regenerator to further promote the combustion of coke and the chemical conversion of CO2 during the partial regeneration of the catalyst in the coking tank, thereby generating high-concentration carbon monoxide as a chemical raw material (the CO content in the first flue gas separated by the first cyclone separator reaches more than 50%), which can generate certain economic benefits. In addition, it also promotes the resource utilization of carbon dioxide to a certain extent, achieving the effect of carbon emission reduction.

[0057] Beneficial Effect 2: The catalytic cracking regeneration method for producing more carbon monoxide provided by this invention utilizes the heat generated by the partial coke-O2 reaction in the first regenerator and the heat generated by the combustion of the semi-regenerated catalyst in the second regenerator. This maintains the overall bed temperature in the first regenerator higher than that in the second regenerator, promoting the endothermic reaction C + CO2 → CO and improving coke burning efficiency. By limiting the coke burning ratio in the first and second regenerators, the coke burning in the second regenerator maintains the first regenerator at a higher temperature, significantly increasing the CO concentration in the flue gas and reducing the purification and separation cost of carbon monoxide. Furthermore, by further limiting the first regenerator to use a rapid fluidized bed operation, the apparent gas linear velocity is higher and the catalyst residence time is shorter, promoting gas-solid contact to facilitate CO2 conversion while reducing catalyst loss caused by prolonged exposure to high temperatures.

[0058] Beneficial Effect 3: The catalytic cracking regeneration method for producing more carbon monoxide provided by this invention introduces pure oxygen into the pre-lift pipe and a gas with low oxygen content and high carbon dioxide content into the coke burner, so that the first regenerator adopts an oxygen-deficient atmosphere as a whole. A portion of the coke is converted through the C+CO2→CO reaction, which can save the total amount of oxygen used during the combustion process of the catalyst regeneration. Under the condition of low oxygen content, on the one hand, the regeneration cost is reduced, and on the other hand, secondary combustion of regeneration flue gas and tail combustion of carbon monoxide that could damage equipment such as cyclone separators can be avoided under high CO concentration conditions.

[0059] Beneficial Effect 4: The catalytic cracking regeneration method for producing more carbon monoxide provided by this invention allows for flexible adjustment of the regenerator catalyst activity, thereby controlling the content of the desired components in the catalytic cracking products. Specifically, by controlling the regeneration temperature, the apparent linear velocity of the regeneration gas, and the oxygen content, the activity of the regenerated catalyst can be adjusted, thereby affecting the depth of the catalytic cracking reaction and thus controlling the content of the desired components in the catalytic cracking products. Attached Figure Description

[0060] Figure 1 This invention provides a schematic diagram of a catalytic cracking regeneration unit combined with a catalytic cracking unit.

[0061] Figure 2 This is a regeneration device for the conventional two-stage parallel regeneration process used in Comparative Example 1 of the present invention. Attached image description:

[0063] 1. First regenerated gas; 2. Pre-lift pipe; 3. Coke burner; 4. First cyclone separator; 5. Dense phase section of the second regenerator; 6. Dilute phase section of the second regenerator; 7. Second cyclone separator; 8. First flue gas outlet; 9. Second flue gas outlet; 10. Third regenerated gas; 11. External heat exchanger; 12. Main air distributor; 13. Catalyst delivery pipeline; 14. Riser reactor; 15. Feedstock oil; 16. Stripping settling section; 17. Third cyclone separator; 18. Reaction product outlet; 19. Pre-lift gas; 20. Regenerated catalyst delivery pipeline; 21. First regenerator; 22. Semi-regenerated catalyst delivery pipeline; 23. Riser reactor; 24. Stripping settling device; 25. Second regenerator; 26. Second regenerated gas. Detailed Implementation

[0064] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0065] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0066] Example 1

[0067] This embodiment provides a catalytic cracking regeneration device, which is a nested two-stage regeneration structure, with the first regenerator located inside the second regenerator;

[0068] The first regenerator includes a coke burner and a pre-lift pipe. The bottom of the coke burner is equipped with a main air distributor for conveying the second regeneration gas. One end of the pre-lift pipe passes through the main air distributor. The other end of the pre-lift pipe is equipped with a first regeneration gas inlet and extends to the bottom outside of the second regenerator. The side wall of the pre-lift pipe on the bottom outside of the second regenerator is equipped with a catalyst inlet. The top of the coke burner is connected to the first cyclone separator.

[0069] The second regenerator has a third regeneration gas inlet at the bottom, a second flue gas outlet at the top, a regeneration catalyst outlet on the bottom side, and a first flue gas outlet on the top side, which is connected to the first cyclone separator; the inner top is equipped with a second cyclone separator, which is connected to the second flue gas outlet.

[0070] The location of the material leg outlet of the first cyclone separator is not specifically limited and can be adjusted according to the actual situation. In one embodiment, the material leg outlet of the first cyclone separator is located in the dense phase section of the second regenerator.

[0071] The location of the material leg outlet of the second cyclone separator is not specifically limited and can be adjusted according to the actual situation. In one embodiment, the material leg outlet of the second cyclone separator is located in the dense phase section inside the second regenerator.

[0072] In one embodiment, the first regenerator is located in a horizontal position in the middle region of the second regenerator; further, the coking tank may be located in the dilute phase region of the second regenerator.

[0073] The ratio of the inner diameter of the coke burner to the pre-lifting pipe and the ratio of the inner diameter of the dense phase section of the second regenerator to the inner diameter of the coke burner are not specifically limited and can be adjusted according to actual needs. In one embodiment, the ratio of the inner diameter of the coke burner to the pre-lifting pipe can be limited to (4-6):1, and the ratio of the inner diameter of the dense phase section of the second regenerator to the inner diameter of the coke burner can be limited to (1.5-2):1.

[0074] The material of the first regenerator is not specifically limited, as long as it meets the requirements of thermal conductivity and wear resistance. Composite materials such as manganese alloy steel, chromium cast iron and carbon steel can be used.

[0075] In one embodiment, a heat exchanger can be installed on the second regenerator to maintain the temperature of the bed inside the second regenerator. The position and number of heat exchangers can be adjusted according to the actual situation. For example, the heat exchanger can be located inside or outside the second regenerator, and at least one heat exchanger can be installed.

[0076] For ease of comparison, the feedstock used in the following examples and comparative examples are all catalytic cracking feedstocks (hereinafter referred to as feedstocks), and their properties are listed in Table 1. The catalysts were produced by the Catalyst Plant of Lanzhou Petrochemical Company of China National Petroleum Corporation, with the product number LDC-200, and their properties are listed in Table 2.

[0077] Table 1

[0078] Molecular weight, g / mol 437 Residual char, m% 3.63 Heavy metals, μg / g Ca 2.2 Cu 0.08 Pb <0.01 Ni 4.42 V 4.69 Fe 4.28 Hydrocarbon composition, m% Saturated hydrocarbons 63.2 Aromatics 33.2 gelatin 3.6 Asphalt /

[0079] Table 2

[0080]

[0081]

[0082] Example 2

[0083] This embodiment provides a catalytic cracking regeneration method that produces more carbon monoxide, employing... Figure 1The apparatus shown, which combines a pilot-scale catalytic cracking riser unit with a catalytic cracking regeneration unit, specifically includes the following steps:

[0084] (1) The coking catalyst from the stripping settling section 16 of the pilot plant of the chemical cracking riser enters the pre-rise pipe 2 of the first regenerator through the catalyst delivery pipeline 13 and the catalyst inlet on the pre-rise pipe 2. The first regeneration gas 1 enters the pre-rise pipe 2 through the first regeneration gas inlet at one end of the pre-rise pipe 2 and mixes with the catalyst to carry out a pre-combustion reaction. The material after the pre-combustion reaction enters the coking tank 3 under the conveying of the first regeneration gas 1 and mixes with the second regeneration gas from the main air distributor 12 to further carry out a partial regeneration reaction. The coking ratio of the first regenerator is controlled at 30%. The amount of regenerated catalyst in the first regenerator (total in the pre-rise pipe and coking tank) accounts for 30% of the total catalyst capacity in the regenerator.

[0085] The first regeneration gas used was pure oxygen; the second regeneration gas used was an oxygen / carbon dioxide mixture, with an oxygen content of 10v% (during the experiment, although a small amount of oxygen from the pre-lift tube was carried into the coke burner, the amount was negligible and within the allowable range of experimental error). The regeneration temperature of the first regenerator (coke burner bed temperature) was 720℃. The residence time of the catalyst in the coke burner was 4 min. The apparent linear velocity of the gas in the pre-lift tube of the first regenerator was 8 m / s, and the apparent linear velocity of the gas in the coke burner was 1 m / s.

[0086] (2) The flue gas carrying the semi-regenerated catalyst passes upward through the first cyclone separator 4 at the top of the coke burner 3 for gas-solid separation. The first flue gas is discharged through the first flue gas outlet 8 and the carbon monoxide in it is captured as a chemical raw material. The semi-regenerated catalyst enters the dense phase section 5 of the second regenerator through the material leg of the first cyclone separator 4. It comes into contact with the third regeneration gas 10 input through the third regeneration gas inlet at the bottom of the second regenerator and undergoes a complete regeneration reaction in the dense phase section 5 of the second regenerator. The incompletely regenerated catalyst is further reacted in the dense phase bed catalyst bed of the second regenerator to achieve complete regeneration. The coke burning ratio of the second regenerator is 70%.

[0087] The third regeneration gas uses air with an oxygen content of 21% v%, and the regeneration temperature of the second regenerator (temperature of the dense phase catalyst bed in the second regenerator) is 700℃. The residence time of the semi-regenerated catalyst in the second regenerator is 8 min, and the apparent linear velocity of the gas in the second regenerator is 0.3 m / s.

[0088] (3) The flue gas generated in the second regenerator is discharged through the second flue gas outlet 9 after most of the entrained catalyst is separated by the second cyclone separator 7 in the dilute phase section 6 of the second regenerator. An external heat exchanger 11 is provided on the outside of the dense phase section 5 of the second regenerator to maintain the temperature of the bed in the second regenerator. The fully regenerated catalyst in the second regenerator enters the riser reactor 14 through the regenerated catalyst conveying pipeline 20 and mixes with the feed oil 15. Under the action of the pre-lifting gas 19, a catalytic cracking reaction occurs. The reacted material rises to the stripping settling section 16 for separation of the coking catalyst and the product. The obtained product continues to rise to the third cyclone separator 17 to separate the residual coking catalyst in the product. The coking catalyst settled in the stripping settling section 16 enters the regenerator for regeneration through the waiting catalyst conveying pipeline 13. The final catalytic cracking product is discharged through the reaction product outlet 18.

[0089] The inner diameter of the dense phase bed in the second regenerator is 180 cm, the inner diameter of the pre-lift pipe in the first regenerator is 18 cm, and the inner diameter of the coke burner is 90 cm. The first regenerator is made of austenitic steel (grade: ZG120Mn7Mo1) and is a coke burner with a pre-lift pipe, operating as a rapid fluidized bed. The second regenerator is a conventional regenerator operating as a bubbling bed.

[0090] The specific regeneration conditions, reaction conditions, carbon content of the regenerated catalyst, and flue gas composition are listed in Table 3.

[0091] Example 3

[0092] This embodiment is similar to Embodiment 2, except that: 1) the second regeneration gas supplied by the main air distributor at the bottom of the coke burner is pure carbon dioxide; 2) the regeneration temperature of the first regenerator is 710°C; 3) the coke burning ratio of the first regenerator is 25%, and the coke burning ratio of the second regenerator is 75%. The regeneration conditions, reaction conditions, carbon determination of the regeneration catalyst, and flue gas composition are all listed in Table 3.

[0093] Example 4

[0094] This embodiment is similar to Embodiment 2, except that: 1) the second regeneration gas supplied by the main air distributor at the bottom of the coke burner is an oxygen / carbon dioxide mixture, with an oxygen content of 5%; 2) the regeneration temperature of the first regenerator is 715°C; 3) the coke burning ratio of the first regenerator is 45%, and the coke burning ratio of the second regenerator is 55%. The regeneration conditions, reaction conditions, carbon determination of the regeneration catalyst, and flue gas composition are all listed in Table 3.

[0095] Example 5

[0096] This embodiment is similar to Embodiment 2, except that: 1) the second regeneration gas supplied by the main air distributor at the bottom of the coke burner is pure carbon dioxide; 2) the regeneration temperature of the first regenerator is 810℃; 3) the regeneration temperature of the second regenerator is 800℃. The regeneration conditions, reaction conditions, carbon content of the regeneration catalyst, and flue gas composition are all listed in Table 3.

[0097] Comparative Example 1

[0098] This comparative example uses a conventional two-stage parallel regeneration process, as shown in the attached diagram. Figure 2 The apparatus shown. The same spent catalyst as in the example is regenerated using a conventional regeneration method, including the following steps:

[0099] The coking catalyst (regenerated catalyst) from the stripping settling tank 24 enters the first regenerator 21 through the regenerated catalyst conveying pipeline 13, and undergoes combustion reaction with it in the first regenerator 21 under the conveying of the first regenerated gas 1. The resulting product is obtained as first flue gas and semi-regenerated catalyst through the cyclone separator at the top of the first regenerator 21. The first flue gas is discharged through the first flue gas outlet 8, and the semi-regenerated catalyst is conveyed to the second regenerator 25 through the semi-regenerated catalyst conveying pipeline 22. It continues to undergo combustion reaction with the second regenerated gas 26 in the second regenerator 25. After the reaction is completed, the second flue gas and regenerated catalyst are separated by the cyclone separator in the second regenerator 25. The second flue gas is discharged through the second flue gas outlet 9, and the regenerated catalyst is input into the riser reactor 23 through the regenerated catalyst conveying pipeline 20.

[0100] In this process, both the first and second regeneration gases are air. The regeneration temperature of the first regenerator is 670℃, and the regeneration temperature of the second regenerator is 700℃. The residence time of the catalyst in the first regenerator is 8 minutes, and the residence time in the second regenerator is 10 minutes. The apparent linear velocity of the gas in the first regenerator is 0.8 m / s, and the apparent linear velocity of the gas in the second regenerator is 0.6 m / s. The regeneration conditions, reaction conditions, carbon determination of the regenerated catalyst, and flue gas composition are all listed in Table 3.

[0101] Table 3

[0102]

[0103]

[0104] As can be seen from the data in the table above, compared with the comparative example, the carbon content on the regenerated catalyst obtained by regeneration using the catalytic cracking regeneration device provided by the present invention is basically the same as that of the traditional two-stage regeneration. Furthermore, the CO content in the first flue gas reaches more than 50% and the remaining gas is mainly CO2. CO2 is easier to compress and liquefy than N2, thereby achieving the separation and purification of CO and significantly reducing the overall cost of CO separation and purification.

[0105] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A catalytic cracking regeneration unit, characterized in that, The catalytic cracking regeneration unit is a nested two-stage regeneration structure, with the first regenerator located inside the second regenerator; The first regenerator includes a coke burner and a pre-lift pipe. The bottom of the coke burner is provided with a main air distributor for conveying the second regeneration gas. One end of the pre-lift pipe passes through the main air distributor. The other end of the pre-lift pipe is provided with a first regeneration gas inlet and extends to the bottom outer side of the second regenerator. The side wall of the pre-lift pipe on the bottom outer side of the second regenerator is provided with a catalyst inlet. The top of the coke burner is connected to a first cyclone separator. The second regenerator has a third regeneration gas inlet at the bottom, a second flue gas outlet at the top, a regeneration catalyst outlet on the bottom side, and a first flue gas outlet on the top side, which is connected to the first cyclone separator; a second cyclone separator is located at the top inside, and the second cyclone separator is connected to the second flue gas outlet. Wherein, the first regenerated gas is oxygen; the second regenerated gas is carbon dioxide, or a mixture of carbon dioxide and oxygen; and the third regenerated gas is an oxygen-containing gas.

2. The catalytic cracking regeneration unit as described in claim 1, characterized in that, The first regenerator is located in the middle region of the second regenerator in a horizontal position.

3. The catalytic cracking regeneration unit as described in claim 1, characterized in that, The inner diameter ratio of the coking tank to the pre-lifting pipe is (4-6):1, and the inner diameter ratio of the dense phase section of the second regenerator to the coking tank is (1.5-2):

1.

4. The catalytic cracking regeneration unit as described in claim 1, characterized in that, The first regenerator is made of thermally conductive and wear-resistant manganese alloy steel, chromium cast iron, or carbon steel.

5. The catalytic cracking regeneration unit as described in claim 1, characterized in that, The second regenerator is provided with at least one heat-collecting device, which is located inside or outside the second regenerator.

6. The catalytic cracking regeneration unit as described in claim 2, characterized in that, The coking tank is located in the dilute phase region of the second regenerator.

7. A catalytic cracking regeneration method for producing more carbon monoxide, characterized in that, The catalytic cracking regeneration apparatus according to any one of claims 1-6 comprises the following steps: The catalyst to be generated is pre-combusted with the first regeneration gas in the pre-lift pipe, and then conveyed upward to the coke burner to mix with the second regeneration gas supplemented by the main air distributor for partial regeneration reaction, while controlling the coke burn ratio of the first regenerator to be 20%-50%; The material discharged from the coking tank is separated into first flue gas and semi-regenerated catalyst by the first cyclone separator; the first flue gas is discharged through the first flue gas outlet; the semi-regenerated catalyst is conveyed to the second regenerator by the material leg of the first cyclone separator to undergo a regeneration reaction with the third regeneration gas, and the coking ratio of the second regenerator is controlled to be 50%-80%.

8. The catalytic cracking regeneration method as described in claim 7, characterized in that, The oxygen in the first regenerated gas has a purity greater than 99% v%. The carbon dioxide used in the second regeneration gas has a purity greater than 99% %. The third regenerated gas is a mixture of carbon dioxide and / or nitrogen and oxygen, or air.

9. The catalytic cracking regeneration method as described in claim 7, characterized in that, The oxygen concentration in the regenerated gas inside the coke burner is not higher than 10V.

10. The catalytic cracking regeneration method as described in claim 9, characterized in that, The oxygen concentration in the regenerated gas inside the coke burner is not higher than 8%.

11. The catalytic cracking regeneration method as described in claim 7, characterized in that, The oxygen concentration of the regenerated gas in the second regenerator is 18v%-30v.

12. The catalytic cracking regeneration method as described in claim 11, characterized in that, The oxygen concentration of the regenerated gas in the second regenerator is 21%-25%.

13. The catalytic cracking regeneration method as described in claim 7, characterized in that, The first regenerator operates in a fast fluidized bed; the second regenerator operates in a bubbling bed or turbulent bed.

14. The catalytic cracking regeneration method as described in claim 7, characterized in that, The amount of catalyst in the first regenerator accounts for 20%-30% of the total capacity of the first regenerator.

15. The catalytic cracking regeneration method as described in claim 7, characterized in that, The operating conditions of the first regenerator are as follows: regeneration temperature is 700-850℃; apparent linear velocity of gas in the pre-lift pipe is 8-10m / s; average residence time of catalyst in the coking tank is 2.0-4.0min; and apparent linear velocity of gas in the coking tank is 1-3m / s.

16. The catalytic cracking regeneration method as described in claim 15, characterized in that, The operating conditions of the first regenerator are: regeneration temperature of 720-820℃; and average residence time of catalyst in the coking tank of 2.5-3.5 min.

17. The catalytic cracking regeneration method as described in claim 7, characterized in that, The temperature of the bed in the second regenerator is 650-820℃.

18. The catalytic cracking regeneration method as described in claim 17, characterized in that, The temperature of the bed in the second regenerator is 670-800℃.

19. The catalytic cracking regeneration method as described in claim 7, characterized in that, The operating conditions of the second regenerator are: regeneration temperature 650-820℃; average residence time of catalyst in the second regenerator 5.0-15.0 min; apparent linear velocity of gas in the second regenerator 0.3-0.9 m / s.

20. The catalytic cracking regeneration method as described in claim 7, characterized in that, The operating conditions of the second regenerator are: regeneration temperature 670-800℃; average residence time of catalyst in the second regenerator is 8.0-12.0 min; apparent linear velocity of gas in the second regenerator is 0.4-0.8 m / s.

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