Method for regenerating spent catalyst from catalytic cracking reaction

Abstract

The present invention relates to a method for regenerating a spent catalyst from a catalytic cracking reaction. The method comprises: (1) from top to bottom, a regenerator is provided with a first regeneration zone and a second regeneration zone communicated with each other, so that a spent catalyst from a catalytic cracking reaction passes through the first regeneration zone and the second regeneration zone in sequence; CO2 is introduced into the lower portion of the first regeneration zone, so that the spent catalyst entering the first regeneration zone is in contact with CO2 and second flue gas that comes from the second regeneration zone for first regeneration to obtain a semi-regenerated catalyst and flue gas; oxygen-containing gas is introduced into the lower portion of the second regeneration zone and is then in contact with the semi-regenerated catalyst for second regeneration to obtain a regenerated catalyst and the second flue gas; wherein the first regeneration zone is a bubbling bed, and the second regeneration zone is a fast fluidized bed; the volume ratio of oxygen in the oxygen-containing gas introduced into the lower portion of the second regeneration zone is greater than or equal to 22%; and the regeneration temperature of the first regeneration is 700-800°C; and (2) at least part of the regenerated catalyst is enabled to return to the catalytic cracking reaction. In the present invention, in the regeneration process of a coke-laden spent catalyst, the coke is converted into flue gas having higher CO selectivity.

Description

A method for regenerating spent catalyst for catalytic cracking reaction Technical Field

[0001] The present invention relates to the technical field of catalytic cracking of petroleum hydrocarbons, and in particular to a method for regenerating a spent catalyst for a catalytic cracking reaction. Background Art

[0002] Catalytic cracking of petroleum feedstock is a key process in petroleum refining. A catalytic cracking unit primarily consists of a catalytic cracking reactor and a catalyst regenerator. In the catalyst regenerator, regeneration gas is used to regenerate the coked catalyst, generating regeneration flue gas. During the catalyst regeneration process, the coke burns, producing large amounts of CO2, making the catalytic cracking unit the largest source of CO2 emissions within a refinery. CO2 in catalytic cracking flue gas accounts for 15% to 50% of total refinery emissions. A catalytic cracking unit emits 211.7 kg of CO2 for every ton of feedstock processed. China has approximately 190 catalytic cracking units, with a total annual processing capacity of approximately 210 million tons, resulting in at least 40 million tons of CO2 emissions.

[0003] During the regeneration process of the catalyst, a large amount of heat is generated, causing the catalytic device to have excess heat. An external heat extraction device is required to convert the heat generated by the catalyst regeneration into steam energy and to recover energy from the high-temperature flue gas. However, this is low-quality energy utilization. In addition, the regenerated flue gas contains carbon monoxide, which often causes tail combustion, causing local overheating of the regenerator and aggravated catalyst deactivation. Tail combustion can be reduced by controlling the oxygen content in the flue gas, but it will reduce the burning rate and burning intensity. At the same time, there is the problem of tail gas emissions, resulting in the loss of chemical energy in the carbon monoxide. Refineries often use carbon monoxide combustion aids or flue gas boilers to reduce carbon monoxide in the flue gas and recover energy, but the problem of carbon monoxide in the flue gas has never been properly solved.

[0004] CN1400159A discloses a method for producing hydrogen from catalytic cracking regeneration flue gas. This method can rationally utilize the CO in the regeneration flue gas and alleviate the problem of excess heat in the FCC unit. However, the CO content obtained by this method is low, at around 14% by volume, while the nitrogen content is above 70% by volume.

[0005] CN102698817A discloses a pure oxygen regeneration process for fluidized catalytic cracking catalysts and a hydrogen production method, which can significantly improve the quality and efficiency of energy utilization, reduce the energy consumption and pollutant emissions of the FCC regeneration system, and simultaneously produce hydrogen through the water-gas shift reaction of the generated CO.

[0006] CN101457152A discloses a hydrocarbon oil conversion method. During the regeneration process, the regenerated catalyst is contacted with water vapor and an oxygen-containing gas in a gasifier to produce synthesis gas and semi-regenerated catalyst. This method can increase the production of carbon monoxide and hydrogen. The carbon monoxide can also be converted into hydrogen in subsequent processing, thereby achieving a higher hydrogen yield.

[0007] However, the existing technology produces hydrogen through incomplete regeneration of flue gas. Although coke is used, carbon is still mainly emitted in the form of carbon dioxide; and the method of directly contacting the regenerated catalyst with water vapor to produce synthesis gas will accelerate the deactivation of the catalyst.

[0008] During the regeneration process of the spent catalyst with carbon deposits produced by the catalytic cracking reaction, how to convert the carbon deposits on the spent catalyst into flue gas with higher CO selectivity, reduce the carbon emissions of the catalytic cracking unit, and produce CO at the same time is a technical problem that needs to be solved urgently.

[0009] Summary of the Invention

[0010] The present invention provides a method for regenerating a spent catalyst for a catalytic cracking reaction, characterized in that it comprises the following steps:

[0011] (1) The regenerator is provided with a first regeneration zone and a second regeneration zone connected from top to bottom, so that the catalyst to be regenerated from the catalytic cracking reaction passes through the first regeneration zone and the second regeneration zone in sequence;

[0012] CO2 is introduced into the lower part of the first regeneration zone, so that the catalyst to be regenerated entering the first regeneration zone contacts with CO2 and the second flue gas from the second regeneration zone for first regeneration, thereby obtaining a semi-regenerated catalyst and flue gas;

[0013] The oxygen-containing gas is introduced into the lower part of the second regeneration zone to contact the semi-regenerated catalyst for second regeneration, thereby obtaining a regenerated catalyst and the second flue gas;

[0014] Wherein, the first regeneration zone is a bubbling bed, and the second regeneration zone is a fast bed;

[0015] The volume percentage of oxygen in the oxygen-containing gas introduced into the lower part of the second regeneration zone is greater than or equal to 22%; the regeneration temperature of the first regeneration is 700-800°C;

[0016] (2) returning at least a portion of the regenerated catalyst to the catalytic cracking reaction.

[0017] Optionally, the bed density of the bubbling bed is 300 to 700 kg / m 3 , preferably 450~650kg / m 3 and / or,

[0018] The bed density of the fast bed is 120-300 kg / m 3 , preferably 180~250kg / m 3 .

[0019] Optionally, the conditions for the first regeneration include: a gas superficial linear velocity of 0.1 to 1 m / s, and an average catalyst residence time of 0.6 to 20 minutes.

[0020] Optionally, the volume proportion of CO2 introduced into the lower part of the first regeneration zone in the total volume of gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone is 1 to 50%, preferably 2 to 15%.

[0021] Optionally, the conditions for the second regeneration include: a regeneration temperature of 600-700° C., a gas superficial velocity of 0.8-4 m / s, and an average catalyst residence time of 0.6-15 minutes.

[0022] Optionally, the oxygen-containing gas introduced into the lower part of the second regeneration zone comprises CO2 and O2 or consists essentially of CO2 and O2;

[0023] The total volume of CO2 introduced into the lower part of the first regeneration zone and the CO2 introduced into the lower part of the second regeneration zone accounts for 1 to 89% of the total volume of gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone, and preferably accounts for 60 to 80%.

[0024] Optionally, the volume ratio of the second regeneration zone to the first regeneration zone is 1:(1-10).

[0025] Alternatively, in a catalytic cracking reaction, the hydrocarbon oil feedstock is brought into contact with the regenerated catalyst in a catalytic cracking reactor to produce reaction oil gas and spent catalyst, which are then separated.

[0026] Optionally, the hydrocarbon oil feedstock includes petroleum hydrocarbons and / or other mineral oils, the petroleum hydrocarbons are selected from a combination of one or more of gasoline, diesel, vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, extracted oil and inferior recycled oil, and the other mineral oils are selected from a combination of one or more of coal liquefaction oil, oil sands oil and shale oil.

[0027] Optionally, the conditions for the catalytic cracking reaction include: a reaction temperature of 450 to 700° C., a reaction time of 1 to 10 seconds, and a catalyst-oil ratio of (1 to 100):1.

[0028] Optionally, the catalytic cracking reactor is a riser reactor, a fluidized bed reactor or a combination of the two.

[0029] Optionally, the flue gas is drawn out from the top of the regenerator and then separated to obtain CO product.

[0030] The present application also provides a catalyst regenerator suitable for a catalytic cracking unit, the regenerator comprising a first regeneration zone, a second regeneration zone, a carbon dioxide inlet, an oxygen-containing gas inlet, an inlet for a catalyst to be regenerated and a regenerated catalyst outlet; the first regeneration zone is configured to allow the catalyst to be regenerated from the catalytic cracking reactor to undergo partial regeneration to produce a semi-regenerated catalyst, wherein the second regeneration zone is located below the first regenerator and is fluidically connected to the first regeneration zone, and the second regeneration zone is configured to allow the semi-regenerated catalyst from the first regeneration zone to undergo a second regeneration when passing downward through the second regeneration zone to produce a regenerated catalyst; the CO2 inlet is located at the lower part of the first regeneration zone, for inputting CO2 gas into the first regeneration zone; the oxygen-containing gas inlet is located at the lower part of the second regeneration zone, for inputting oxygen-containing gas into the second regeneration zone; the catalyst to be regenerated inlet is configured to feed the catalyst to be regenerated from the catalytic cracking reactor into the first regeneration zone; the regenerated catalyst outlet is configured to transport the regenerated catalyst out of the second regeneration zone; wherein the first regeneration zone is a bubbling bed and the second regeneration zone is a fast bed. Beneficial effects:

[0031] (1) The present invention controls the combustion of coke during the catalyst regeneration process, causing it to undergo incomplete combustion to generate CO, and stores part of the energy in CO as chemical energy. This can reduce excess heat during the catalytic regeneration process, solve the problem of regenerator tail combustion, and significantly reduce CO2 emissions without affecting the catalyst regeneration effect.

[0032] (2) Strengthen the reaction between CO2 and coke to further increase CO production. On the one hand, this reaction reduces the CO2 produced by the complete oxidation of coke, reducing carbon emissions; on the other hand, it converts CO2 back into CO, which is reflected in negative carbon emissions.

[0033] (3) No N2 is introduced during the regeneration process, which is beneficial to the separation of CO and CO2 and reduces separation energy consumption.

[0034] (4) The generated CO can be used as a raw material for subsequent chemical and metallurgical industries, which can save raw materials such as coal and methane for CO production, save resources and energy consumption, and further reduce emissions.

[0035] (5) In the context of carbon neutrality and carbon peak goals, the production of CO by catalytic cracking regeneration process can achieve waste-to-treasure and energy conservation and emission reduction, which has huge economic and social benefits.

[0036] (6) Replacing N2 in the conventional regeneration process with CO2 is beneficial to alleviate the local overheating of the catalyst during the burning process and slow down the hydrothermal deactivation of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0038] FIG1 is a schematic diagram of a specific embodiment of a process of a method for regenerating a spent catalytic cracking catalyst or a system for regenerating a spent catalytic cracking catalyst according to the present invention;

[0039] FIG2 is a schematic diagram of the catalytic cracking process of the single-stage regeneration method in Comparative Examples 3 and 5 of the present invention;

[0040] Description of reference numerals:

[0041] 1 Hydrocarbon oil feed inlet 2 Catalytic cracking reactor 3 Settler

[0042] 4 Reaction oil and gas outlet 5 Waiting slide valve 6 Regenerator

[0043] 7 Oxygen-containing gas inlet 8 Second regeneration zone 9 First regeneration zone

[0044] 10 Flue gas outlet 11 Energy recovery and separation unit 12 CO product outlet

[0045] 13 Other flue gas component outlet 14 Regeneration slide valve 15 CO2 inlet

[0046] 21 Catalytic cracking feedstock 22 Riser reactor 23 Second settler

[0047] 24 Reaction oil and gas 25 Second slide valve to be regenerated 26 Second regenerator

[0048] 27 Regeneration flue gas 28 Regeneration gas inlet 29 Second regeneration slide valve DETAILED DESCRIPTION

[0049] The present application will be further described in detail below through the accompanying drawings and examples, through which the features and advantages of the present application will become more clear and distinct.

[0050] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0051] Any specific numerical value disclosed herein (including the endpoints of a numerical range) is not limited to the exact value of the numerical value, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Moreover, for a disclosed numerical range, any combination of the endpoints of the range, between the endpoints and the specific points in the range, and between the specific points can be used to generate one or more new numerical ranges, and these new numerical ranges should also be considered to be specifically disclosed herein.

[0052] In the present application, it should be noted that the terms "upper", "lower", "inside", "outside", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships in the working state of the present application. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present application.

[0053] In this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," "connected," and "connected" should be understood broadly. A person of ordinary skill in the art will understand the specific meanings of these terms in this application based on the specific circumstances. For example, in this application, the term "connected" includes both direct connection between two devices and connection via one or more intermediate devices.

[0054] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0055] Although the terms first, second, third, etc. can be used to describe various steps, elements, components, regions, layers and / or sections in this article, these steps, elements, components, regions, layers and / or sections should not be limited by these terms unless otherwise specified. These terms can only be used to distinguish a step, element, component, region, layer or section from another step, element, component, region, layer or section. Unless clearly indicated in the context, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in this article. Therefore, the first step, element, component, region, layer or section discussed below can be referred to as the second step, element, component, region, layer or section without departing from the teachings of exemplary embodiments.

[0056] Unless otherwise specified, the terms used herein have the same meaning as commonly understood by those skilled in the art. If a term is defined herein and its definition is different from the commonly understood meaning in the art, the definition herein shall prevail.

[0057] The present invention relates to a method for regenerating a spent catalyst for a catalytic cracking reaction, the method comprising the following steps:

[0058] (1) The regenerator is provided with a first regeneration zone and a second regeneration zone connected from top to bottom, so that the catalyst to be regenerated from the catalytic cracking reaction passes through the first regeneration zone and the second regeneration zone in sequence;

[0059] CO2 is introduced into the lower part of the first regeneration zone, so that the catalyst to be regenerated entering the first regeneration zone contacts with CO2 and the second flue gas from the second regeneration zone for first regeneration, thereby obtaining a semi-regenerated catalyst and flue gas;

[0060] The oxygen-containing gas is introduced into the lower part of the second regeneration zone to contact the semi-regenerated catalyst for second regeneration, thereby obtaining a regenerated catalyst and the second flue gas;

[0061] Wherein, the first regeneration zone is a bubbling bed, and the second regeneration zone is a fast bed;

[0062] The volume percentage of oxygen in the oxygen-containing gas introduced into the lower part of the second regeneration zone is greater than or equal to 22%; the regeneration temperature of the first regeneration is 700-800°C;

[0063] (2) returning at least a portion of the regenerated catalyst to the catalytic cracking reaction.

[0064] In the context of the present invention, semi-regenerated catalyst refers to a partially regenerated catalyst produced by partially burning spent catalyst from a catalytic cracking reactor. The meanings of bubbling bed and fast bed are well known in the art.

[0065] Alternatively, in a catalytic cracking reaction, the hydrocarbon oil feedstock is brought into contact with the regenerated catalyst in a catalytic cracking reactor to produce reaction oil gas and spent catalyst, which are then separated.

[0066] It should be noted that during the catalytic cracking reaction, the separated reaction oil and gas can be fed into a subsequent separation system to obtain a variety of catalytic cracking products. The reaction oil and gas can be separated by the subsequent separation system to obtain fractions such as dry gas, liquefied gas, stabilized gasoline, and catalytic diesel. The separation method can be conventional in the art and is not limited by the present invention and will not be described in detail here. The spent catalyst is derived from the catalytic cracking reactor of the hydrocarbon oil feedstock.

[0067] In step (1), the catalyst to be regenerated first enters the first regeneration zone and flows downward, and is countercurrently contacted with the CO2 introduced from the lower part of the first regeneration zone and the second flue gas from the second regeneration zone for the first regeneration, thereby obtaining flue gas and a semi-regenerated catalyst; the obtained semi-regenerated catalyst continues to flow downward to the second regeneration zone and is countercurrently contacted with the oxygen-containing gas introduced from the lower part of the second regeneration zone for the second regeneration, thereby obtaining a regenerated catalyst and a second flue gas. The second flue gas entering the first regeneration zone is the gas obtained after the reaction between the oxygen-containing gas and the semi-regenerated catalyst. The CO2 introduced from the lower part of the first regeneration zone and the oxygen-containing gas introduced from the lower part of the second regeneration zone form the regeneration gas or regeneration atmosphere of the regenerator.

[0068] In step (2), the regenerated regenerated catalyst can be transported in whole or in part to the catalytic cracking reactor for recycling. At least a portion of the catalytic cracking catalyst used for the catalytic cracking reaction is a regenerated catalyst, preferably all of it is a regenerated catalyst. Preferably, the method of the present invention further comprises degassing the regenerated catalyst obtained by the second regeneration and then returning it to the catalytic cracking reactor for recycling. An internal heat exchanger or an external heat exchanger can be provided in the regenerator, and the type, connection and operation of the heat exchanger are well known to those skilled in the art. The flue gas obtained by the regenerator is separated to obtain a CO product. The separation method for separating the flue gas to obtain the CO product can adopt chemical absorption method, membrane separation method, pressure swing adsorption method, deep cooling method, COSORB method or other separation and purification methods well known to those skilled in the art, preferably chemical absorption method. Before separating the flue gas to obtain CO, the flue gas can be purified to remove impurities such as sulfides and nitrides.

[0069] It should be noted that the regeneration temperature in the first regeneration zone can be adjusted by preheating the supplementary CO2 or taking in heat from outside. The supplementary CO2 can exchange heat with the high-temperature catalyst and high-temperature flue gas in the second regeneration zone.

[0070] Similarly, the oxygen-containing gas may be preheated, and the preheating may be carried out by heat exchange with the high-temperature catalyst, high-temperature flue gas, etc. in the regeneration zone.

[0071] In the present disclosure, the first regeneration zone is the area above the CO2 inlet of the lower part of the first regeneration zone in the regenerator. Correspondingly, the second regeneration zone is the area below the CO2 inlet in the regenerator.

[0072] It is easy to imagine that a gas distributor can be provided at the CO inlet and the oxygen-containing gas inlet to facilitate uniform distribution of the gas. A fluid distribution plate can be provided above the gas distributor to help uniformly distribute the material and gas.

[0073] It should be noted that the use of a bubbling bed in the first regeneration zone achieves the following: while maintaining the fluidized state of the catalyst, it increases the coke-to-oxygen ratio, increases catalyst residence time, and promotes more incomplete combustion of coke to produce CO, thereby reducing the generation of CO2 from coke combustion in the second regeneration zone. The use of a fast bed in the second regeneration zone improves coke burning efficiency, rapidly and completely converting coke on the semi-regenerated catalyst under oxygen-rich conditions, effectively restoring catalyst activity.

[0074] More importantly, the inventors of the present application discovered during many years of research and development that in the method of the present application, oxygen-containing gas is introduced into the lower part of the second regeneration zone, CO2 is introduced into the lower part of the first regeneration zone, and at the same time, the first regeneration zone is made a bubbling bed and the second regeneration zone is made a fast bed, so that the CO selectivity is significantly improved.

[0075] The volume proportion of oxygen in the oxygen-containing gas introduced into the lower part of the second regeneration zone is preferably 22%-50%, more preferably 22%-45%.

[0076] It should be noted that in the method for regenerating the spent catalyst for catalytic cracking reaction of the present invention, under the premise that gas is introduced into the lower part of the first regeneration zone and the second regeneration zone as above, and the bed types of the first regeneration zone and the second regeneration zone are simultaneously controlled as above, the regeneration temperature of the first regeneration is 700-800°C, so that the carbon deposits on the spent catalyst are converted into flue gas with higher CO selectivity; the regeneration temperature of the first regeneration is preferably 740-780°C, which can further improve the CO selectivity.

[0077] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction according to the present invention, the bed density of the bubbling bed is 300 to 700 kg / m 3 and / or,

[0078] The bed density of the fast bed is 120-300 kg / m 3 .

[0079] It should be noted that the bed density of the bubbling bed is preferably 450 to 650 kg / m 3 The bed density of the fast bed is preferably 180-250 kg / m 3 .

[0080] It should be noted that in the method for regenerating the spent catalyst for catalytic cracking reaction of the present invention, by controlling the bed density of the bubbling bed and the bed density of the fast bed as above, the coke on the spent catalyst for catalytic cracking can be better converted into carbon monoxide, so that the coke is converted into flue gas with higher CO selectivity, thereby greatly reducing CO2 emissions. In addition, by changing the regeneration burning method to produce carbon monoxide, the tail combustion can be effectively reduced and the catalyst deactivation rate can be slowed down.

[0081] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction of the present invention, the first regeneration conditions include: a gas superficial linear velocity of 0.1 to 1 m / s and an average catalyst residence time of 0.6 to 20 minutes.

[0082] It should be noted that in the first regeneration zone, the gas superficial linear velocity is preferably 0.5 to 1 m / s, and the average residence time of the catalyst is preferably 5 to 15 minutes.

[0083] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction according to the present invention, the volume proportion of the CO2 introduced into the lower part of the first regeneration zone in the total volume of the gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone is 1 to 50%, preferably 2 to 15%. The total volume of gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone refers to the total volume of the CO2 gas introduced into the lower part of the first regeneration zone and the oxygen-containing gas introduced into the lower part of the second regeneration zone. In the context of the present disclosure, the gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone is also simply referred to as regeneration gas.

[0084] It should be noted that the present invention controls the conditions of the first regeneration as described above, and controls the amount of CO2 introduced into the lower part of the first regeneration zone as described above, which is beneficial for converting the carbon deposits on the regenerated catalyst into flue gas with higher CO selectivity.

[0085] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction according to the present invention, the conditions for the second regeneration include: a regeneration temperature of 600-700°C, a gas superficial velocity of 0.8-4 m / s, and an average catalyst residence time of 0.6-15 minutes.

[0086] It should be noted that, in the second regeneration, the regeneration temperature is preferably 650 to 690° C., and the average catalyst residence time is preferably 2 to 10 minutes.

[0087] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction of the present invention, the oxygen-containing gas introduced into the lower part of the second regeneration zone comprises CO2 and O2, or is substantially composed of CO2 and O2;

[0088] The total volume of CO2 introduced into the lower part of the first regeneration zone and the CO2 introduced into the lower part of the second regeneration zone accounts for 1 to 89% of the total volume of gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone, and preferably accounts for 60 to 80%.

[0089] Preferably, the regeneration gas in the regenerator does not contain N2 and / or air, and oxygen and CO2 are used as regeneration gases, and part of the CO2 is converted into CO; without introducing nitrogen, a simpler method can be adopted to separate and obtain a higher purity CO product, while also playing the role of enriching CO2, which is beneficial to carbon capture and utilization.

[0090] It should be noted that by controlling the conditions of the second regeneration as above, controlling the proportion of the total amount of CO2 introduced into the two regeneration zones in the regeneration gas (the oxygen content in the regeneration gas is controlled at the same time), and the proportion of CO2 introduced into the first regeneration zone in the regeneration gas, the semi-regenerated catalyst can be completely regenerated in the second regeneration zone without affecting the activity of the catalytic cracking reaction; and it is conducive to better incomplete combustion, reducing combustion heat, alleviating the problem of excess heat in the catalytic device, and significantly increasing the CO content in the flue gas, which is conducive to the subsequent further purification and application of CO, and the CO selectivity can reach more than 70%, or even more than 81%.

[0091] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction according to the present invention, the volume ratio of the second regeneration zone to the first regeneration zone is 1:(1-10).

[0092] It should be noted that the volume ratio of the second regeneration zone to the first regeneration zone is preferably 1:2-6. This ratio helps prolong the residence time of the regenerated catalyst in the first regeneration zone, allowing more coke to burn to produce CO and reducing the carbon content on the semi-regenerated catalyst. This achieves a higher CO concentration in the regenerated flue gas and substantially or completely regenerated the catalyst.

[0093] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction according to the present invention, in the catalytic cracking reaction, the hydrocarbon oil feedstock includes petroleum hydrocarbons and / or other mineral oils, the petroleum hydrocarbons are selected from a combination of one or more of gasoline, diesel, vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, extracted oil and inferior recycled oil, and the other mineral oils are selected from a combination of one or more of coal liquefaction oil, oil sands oil and shale oil.

[0094] It should be noted that the method of regenerating spent catalysts for catalytic cracking reactions of the present invention has a wide range of applicability. The spent catalysts with carbon deposits produced by catalytic cracking reactions of the above-mentioned various hydrocarbon oil feedstocks can all be converted into flue gas with high CO selectivity through the above-mentioned regeneration process.

[0095] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction of the present invention, the conditions of the catalytic cracking reaction include: a reaction temperature of 450-700°C, a time of 1-10 seconds, and a catalyst-oil ratio of (1-100):1.

[0096] It should be noted that the reaction temperature is preferably 500-650°C, more preferably 550-630°C; the reaction time is preferably 2-5 seconds, and the catalyst-oil ratio (weight ratio of catalytic cracking catalyst to hydrocarbon oil feedstock) is preferably 5-30:1.

[0097] In the present invention, as a variation of the embodiment, water vapor can also be injected into the catalytic cracking reactor. The water vapor is preferably injected in the form of atomized steam. The weight ratio of the injected water vapor to the hydrocarbon oil feedstock can be 0.01 to 1:1, preferably 0.05 to 0.5:1.

[0098] The catalytic cracking catalyst used in the catalytic cracking reaction may include 15 to 65% by weight of natural minerals, 10 to 30% by weight of inorganic oxides, and 25 to 75% by weight of zeolite. The zeolite as the active component is preferably one or more mixtures of Y zeolite, mordenite, beta zeolite, and zeolites with an MFI structure (e.g., ZSM series zeolites and / or ZRP zeolites). The natural minerals are selected from one or more of kaolin, halloysite, montmorillonite, diatomaceous earth, attapulgite, sepiolite, halloysite, hydrotalcite, bentonite, and rectorite. The inorganic oxide is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, titanium oxide, and amorphous silica-aluminum.

[0099] According to a specific embodiment of the method for regenerating a spent catalyst for a catalytic cracking reaction of the present invention, the catalytic cracking reactor is a riser reactor, a fluidized bed reactor, or a combination of the two.

[0100] It should be noted that the catalytic cracking reactor can be a conventional catalytic cracking riser reactor, a fluidized bed reactor or a combination thereof known to those skilled in the art, for example, a catalytic cracking riser reactor connected in series with a fluidized bed reactor. The riser reactor can be selected from a constant diameter riser reactor and / or a constant linear velocity riser reactor, preferably a constant diameter riser. The fluidized bed reactor is located downstream of the riser reactor and is connected to the outlet of the riser reactor. The riser reactor includes a pre-lifting section and at least one reaction zone from bottom to top. In order to allow the crude oil to fully react and according to different target product quality requirements, the reaction zones can be 2 to 8, preferably 1 to 3.

[0101] According to a second aspect of the present invention, the present application provides a catalyst regenerator suitable for a catalytic cracking unit, the regenerator comprising a first regeneration zone, a second regeneration zone, a carbon dioxide inlet, an oxygen-containing gas inlet, a catalyst to be regenerated inlet and a regenerated catalyst outlet; the first regeneration zone is configured to allow the catalyst to be regenerated from the catalytic cracking reactor to undergo partial regeneration to produce a semi-regenerated catalyst, wherein the second regeneration zone is located below the first regenerator and is fluidically connected to the first regeneration zone, and the second regeneration zone is configured to allow the semi-regenerated catalyst from the first regeneration zone to undergo a second regeneration as it passes downward through the second regeneration zone to produce a regenerated catalyst; the CO2 inlet is located at the lower part of the first regeneration zone for inputting CO2 gas into the first regeneration zone; the oxygen-containing gas inlet is located at the lower part of the second regeneration zone for inputting oxygen-containing gas into the second regeneration zone; the catalyst to be regenerated inlet is configured to feed the catalyst to be regenerated from the catalytic cracking reactor into the first regeneration zone; the regenerated catalyst outlet is configured to transport the regenerated catalyst out of the second regeneration zone; wherein the first regeneration zone is a bubbling bed and the second regeneration zone is a fast bed.

[0102] According to a preferred embodiment, the regenerator also has a flue gas outlet and an energy recovery and separation unit. The flue gas outlet is arranged at the top of the regenerator for discharging the flue gas from the first regeneration zone. The energy recovery and separation unit is connected to the flue gas outlet for recovering energy from the flue gas and separating the flue gas into CO products and other flue gas components.

[0103] According to a preferred embodiment, the spent catalyst inlet of the regenerator is communicated with the spent catalyst outlet of the catalytic cracking reactor, and the regenerated catalyst outlet of the regenerator is communicated with the regenerated catalyst inlet of the catalytic cracking reactor.

[0104] The preferred embodiments of the regeneration method and system of the present application will be further described in detail below with reference to the accompanying drawings.

[0105] As shown in FIG1 , the method for regenerating a spent catalyst for a catalytic cracking reaction according to the present invention can be implemented in a system for regenerating a spent catalyst for a catalytic cracking reaction, the system comprising a catalytic cracking reaction unit, a regenerator 6 and an energy recovery and separation unit 11;

[0106] The catalytic cracking reaction unit includes a catalytic cracking reactor 2 and a settler 3. The catalytic cracking reactor 2 is provided with a hydrocarbon oil feedstock inlet 1, a catalyst inlet and an oil agent outlet. The oil agent outlet of the catalytic cracking reactor 2 is connected to the inlet of the settler 3. The settler 3 is provided with a catalyst outlet to be produced and a reaction oil and gas outlet 4.

[0107] The outlet of the catalyst to be regenerated of the settler 3 is connected to the inlet of the catalyst to be regenerated of the regenerator 6 through a catalyst to be regenerated pipeline, and the catalyst to be regenerated pipeline is provided with a slide valve 5;

[0108] The regenerator 6 is provided with a first regeneration zone 9 and a second regeneration zone 8 connected from top to bottom. A CO2 inlet 15 is provided at the lower portion of the first regeneration zone 9, and an oxygen-containing gas inlet 7 is provided at the lower portion of the second regeneration zone 8;

[0109] The first regeneration zone 9 is a bubbling bed, and the second regeneration zone 8 is a fast bed;

[0110] The second regeneration zone 8 is provided with a regenerated catalyst outlet, which is connected to the catalyst inlet of the catalytic cracking reactor 2 through a regenerated catalyst pipeline, and the regenerated catalyst pipeline is provided with a regeneration slide valve 14;

[0111] The top of the regenerator 6 is provided with a flue gas outlet 10, which communicates with the inlet of the energy recovery and separation unit 11. The energy recovery and separation unit 11 is also provided with a CO product outlet 12 and an outlet 13 for other flue gas components. When the oxygen-containing gas consists primarily of CO2 and O2, the other flue gas components primarily contain CO2. Some or all of the CO2, with or without purification, can be returned to the regenerator. The CO2 can be returned to the lower portion of the first regeneration zone or, after mixing with O2 in appropriate proportions, returned to the lower portion of the second regenerator.

[0112] The regenerated slide valve 5 and the regeneration slide valve 14 are used to adjust the flow rates of the regenerated catalyst and the regenerated catalyst, respectively.

[0113] It should be noted that the method for regenerating a spent catalytic cracking catalyst of the present invention, or the system for regenerating a spent catalytic cracking catalyst of the present invention, not only reduces carbon dioxide emissions from the catalytic device and produces CO, thereby turning waste into treasure and fully utilizing resources, and improving the economic benefits of the catalytic cracking device; at the same time, CO is used as a raw material for subsequent chemical processes, thereby saving fossil resources such as coal, oil, and methane used to produce CO, reducing energy consumption and investment, reducing pollution, and improving the economic and social benefits of the petrochemical industry.

[0114] The present invention is further described in detail below by way of examples, but is not intended to be limiting thereof. In the following examples, unless otherwise specified, all experimental instruments and raw materials involved are commercially available products. The feedstock oil used in the examples and comparative examples is Anqing wax oil, the properties of which are shown in Table 1.

[0115] The catalytic cracking catalyst used in the examples and comparative examples has a trade name of CDOS (produced by Sinopec Catalyst Co., Ltd., Changling Branch).

[0116] Table 1

[0117] *Note: In the element determinations described above, S, N, C and H are determined using different methods and their total content may be slightly higher than 100%.

[0118] Example 1

[0119] As shown in FIG1 , a hydrocarbon oil feedstock enters a catalytic cracking reactor 2 (riser reactor) from a hydrocarbon oil feedstock inlet 1 at the bottom thereof, contacts a regenerated catalyst, and reacts. The reaction oil gas and catalyst flow upward to a settler 3 for gas-solid separation. The separated reaction oil gas is then transferred to a subsequent separation system via a reaction oil gas outlet 4. The regenerated catalyst enters a first regeneration zone 9 of a regenerator 6 via a regeneration slide valve 5, where it contacts a second flue gas from a second regeneration zone 8 and CO2 introduced from a CO2 inlet 15 at the bottom of the first regeneration zone 9 for a first regeneration to obtain a semi-regenerated catalyst. The semi-regenerated catalyst then flows downward into the second regeneration zone 8, where it contacts an oxygen-containing gas (a mixture of CO2 and O2) entering from an oxygen-containing gas inlet 7 for a second regeneration to obtain a regenerated catalyst. The regenerated catalyst returns to the bottom of the catalytic cracking reactor 2 (riser reactor) via a regeneration slide valve 14, where it contacts the hydrocarbon oil feedstock and reacts. After exiting the flue gas outlet 10, the regenerated flue gas undergoes gas-solid separation and is then led out of the regenerator 6 to the subsequent energy recovery and separation unit 11. Separation yields carbon monoxide (output at the CO product outlet 12) and other flue gas components (output at the other flue gas component outlet 13). The first regeneration zone 9 is a bubbling bed, while the second regeneration zone 8 is a fast bed. The relevant operating conditions and products are listed in Table 2.

[0120] Example 2

[0121] The method for regenerating the spent catalyst for catalytic cracking reaction is the same as that in Example 1, except that the temperature in the first regeneration zone is 700° C. The relevant operating conditions and products are listed in Table 2.

[0122] Example 3

[0123] The method for regenerating the spent catalyst for catalytic cracking reaction is the same as that in Example 1, except that the temperature in the first regeneration zone is 770° C. The relevant operating conditions and products are listed in Table 2.

[0124] Example 4

[0125] The method for regenerating the spent catalyst for the catalytic cracking reaction is the same as that in Example 1, except that the proportion of oxygen in the regeneration gas is 36.77%. The relevant operating conditions and products are listed in Table 2.

[0126] Example 5

[0127] The method for regenerating the spent catalyst for the catalytic cracking reaction was the same as in Example 1, except that the residence time of the catalyst in the first regeneration zone was 7 minutes. The relevant operating conditions and products are listed in Table 2.

[0128] Example 6

[0129] The method for regenerating the spent catalyst for the catalytic cracking reaction was the same as in Example 1, except that the proportion of oxygen in the regeneration gas was 20.19. The relevant operating conditions and products are listed in Table 2.

[0130] Comparative Example 1

[0131] The method for regenerating the spent catalyst for catalytic cracking reaction in Comparative Example 1 was the same as that in Example 1, except that the temperature in the first regeneration zone was 660° C. The relevant operating conditions and products are listed in Table 3.

[0132] Comparative Example 2

[0133] The method for regenerating the spent catalyst for catalytic cracking reaction in Comparative Example 2 was the same as that in Example 1, except that the temperature in the first regeneration zone was 620° C. The relevant operating conditions and products are listed in Table 3.

[0134] Comparative Examples 3 and 5

[0135] The experiment was conducted according to the flow chart in FIG2 . Catalytic cracking feedstock 21 entered the bottom of the riser reactor 22, where it came into contact with the regenerated catalyst for reaction. The reaction oil vapor and catalyst flowed upward to the second settler 23 for gas-solid separation. The separated reaction oil vapor 24 was then transferred to a subsequent separation system. The regenerated catalyst passed through a second regeneration slide valve 25 and entered a second regenerator 26 where it came into contact with the regeneration gas for regeneration. The regeneration gas entered the second regenerator 26 through a regeneration gas inlet 28. Regenerated flue gas 27 exited the second regenerator 26 and was transferred to a subsequent energy recovery system. The regenerated catalyst then returned to the bottom of the riser reactor 22 via a second regeneration slide valve 29 where it came into contact with the catalytic cracking feedstock 21 for reaction. Comparative Example 5 differs from Comparative Example 3 in that air was used for regeneration. The relevant operating conditions and products are listed in Table 3.

[0136] Comparative Example 4

[0137] The method for regenerating the spent catalyst for catalytic cracking reaction in Comparative Example 4 is the same as that in Example 1, except that the proportion of oxygen in the regeneration gas is 19.32%. The relevant operating conditions and products are listed in Table 3.

[0138] Comparative Example 6

[0139] The method for regenerating the spent catalyst for catalytic cracking reaction in Comparative Example 6 is the same as that in Example 1, except that the proportion of oxygen in the regeneration gas is 19.32%. The relevant operating conditions and products are listed in Table 3.

[0140] Comparative Example 7

[0141] The method for regenerating the spent catalyst for catalytic cracking reaction in Comparative Example 7 is the same as that in Example 1, except that the second regeneration zone is a bubbling bed. The relevant operating conditions and products are listed in Table 3.

[0142] Comparative Example 8

[0143] The method for regenerating the spent catalyst for catalytic cracking reaction in Comparative Example 8 is the same as that in Example 1, except that the first regeneration zone is a fast bed. The relevant operating conditions and products are listed in Table 3.

[0144] In the following examples and comparative examples, the calculation method of CO selectivity is as follows:

[0145] In the CO selectivity calculation formula, the amount of CO substance generated represents the amount of CO substance in the flue gas obtained by the regenerator, and the amount of carbon substance in the coke represents the amount of carbon substance in the coke or carbon deposits on the deposited catalyst to be regenerated entering the regenerator.

[0146] Table 2

[0147] Note: The regeneration gas includes CO2 introduced into the first regeneration zone and O2 and CO2 introduced into the second regeneration zone. The volume proportion of supplementary CO2 in the regeneration gas represents the volume proportion of CO2 introduced into the first regeneration zone in the regeneration gas.

[0148] Table 3

[0149] Note: *Comparative Examples 3 and 5 used a regenerator having only one regeneration zone, i.e., the second regenerator. The regeneration conditions here refer to the regeneration conditions of the second regenerator.

[0150] The results of the examples show that the method of the present invention has the advantage of significantly reducing carbon dioxide emissions and increasing carbon monoxide production. As can be seen from the comparison of Examples 1-3 with Comparative Example 1, when the regeneration temperature of the first regeneration is within the range required by this application, CO selectivity is improved and the CO content in the flue gas composition is increased. When the regeneration temperature of the first regeneration is within the preferred range of this application, CO selectivity and CO content in the flue gas composition are further improved. As can be seen from the comparison of Example 1 with Comparative Examples 3 and 5, compared with the second regenerator using a single regeneration zone, the regenerator according to the present invention, which is divided into a first regeneration zone and a second regeneration zone, improves CO selectivity and increases CO content in the flue gas composition. As can be seen from the comparison of Example 1 and Example 4 with Comparative Example 4, when the volume fraction of oxygen in the oxygen-containing gas introduced into the lower part of the second regeneration zone is within the range required by this application, CO selectivity is improved and CO content in the flue gas composition is increased. As can be seen from the comparison of Example 1 with Comparative Example 6, using CO2 instead of nitrogen or air improves CO selectivity and increases CO content in the flue gas composition. As can be seen from the comparison of Example 1 with Comparative Examples 7 and 8, the combination of a bubbling bed and a fast bed in the regenerator according to the present application leads to improved CO selectivity and increased CO content in the flue gas composition. Compared with Comparative Example 7, the regenerator of the present application has a faster regeneration speed.

[0151] The present application has been described above in conjunction with preferred embodiments, but these embodiments are merely exemplary and serve only as an illustrative example. On this basis, various replacements and improvements can be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A method for regenerating a spent catalyst for a catalytic cracking reaction, characterized in that: The method comprises the following steps: (1) The regenerator is provided with a first regeneration zone and a second regeneration zone connected from top to bottom, so that the catalyst to be regenerated from the catalytic cracking reaction passes through the first regeneration zone and the second regeneration zone in sequence; CO2 is introduced into the lower part of the first regeneration zone, so that the catalyst to be regenerated entering the first regeneration zone contacts with CO2 and the second flue gas from the second regeneration zone for first regeneration, thereby obtaining a semi-regenerated catalyst and flue gas; The oxygen-containing gas is introduced into the lower part of the second regeneration zone to contact the semi-regenerated catalyst for second regeneration to obtain a regenerated catalyst and the second flue gas; Wherein, the first regeneration zone is a bubbling bed, and the second regeneration zone is a fast bed; The volume proportion of oxygen in the oxygen-containing gas introduced into the lower part of the second regeneration zone is greater than or equal to 22%; the regeneration temperature of the first regeneration is 700-800°C, preferably 740-780°C; (2) returning at least a portion of the regenerated catalyst to the catalytic cracking reaction.

2. The method for regenerating a spent catalyst for a catalytic cracking reaction according to claim 1, characterized in that: The bed density of the bubbling bed is 300-700 kg / m 3 , preferably 450~650kg / m 3 and / or, The bed density of the fast bed is 120-300 kg / m 3 , preferably 180~250kg / m 3 .

3. The method for regenerating a spent catalyst for a catalytic cracking reaction according to claim 1 or 2, characterized in that: The conditions for the first regeneration include: the gas superficial linear velocity is 0.1 to 1 m / s, preferably 0.5 to 1 m / s, and the average residence time of the catalyst is 0.6 to 20 minutes, preferably 5 to 15 minutes.

4. The method for regenerating a spent catalyst for a catalytic cracking reaction according to any one of claims 1 to 3, characterized in that: The volume proportion of CO2 introduced into the lower part of the first regeneration zone in the total volume of gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone is 1 to 50%, preferably 2 to 15%.

5. The method for regenerating a spent catalyst for a catalytic cracking reaction according to any one of claims 1 to 4, characterized in that: The conditions for the second regeneration include: a regeneration temperature of 600-700° C., preferably 650-690° C., a gas superficial velocity of 0.8-4 m / s, and an average catalyst residence time of 0.6-15 minutes, preferably 2-10 minutes.

6. The method for regenerating a spent catalyst for a catalytic cracking reaction according to any one of claims 1 to 5, characterized in that: The oxygen-containing gas introduced into the lower part of the second regeneration zone contains CO2 and O2 or is substantially composed of CO2 and O2; preferably, the volume proportion of oxygen in the oxygen-containing gas is greater than or equal to 22%; The total amount of CO2 introduced into the lower part of the first regeneration zone and the CO2 introduced into the lower part of the second regeneration zone accounts for 1 to 89% by volume of the total amount of gas introduced into the lower part of the first regeneration zone and the lower part of the second regeneration zone, and preferably accounts for 60 to 80% by volume.

7. The method for regenerating a spent catalyst for a cracking reaction according to any one of claims 1 to 6, characterized in that: The volume ratio of the second regeneration zone to the first regeneration zone is 1:(1-10), preferably 1:(2-6).

8. The method for regenerating a spent catalyst for a cracking reaction according to any one of claims 1 to 7, characterized in that: In the catalytic cracking reaction, the hydrocarbon oil feedstock is brought into contact with the regenerated catalyst in a catalytic cracking reactor to produce reaction oil gas and spent catalyst and separate them.

9. The method for regenerating a spent catalyst for a catalytic cracking reaction according to claim 8, wherein the hydrocarbon oil feedstock comprises petroleum hydrocarbons and / or other mineral oils, the petroleum hydrocarbons are selected from a combination of one or more of gasoline, diesel, vacuum wax oil, atmospheric wax oil, coker wax oil, deasphalted oil, vacuum residue oil, atmospheric residue oil, extracted oil and inferior recycled oil, and the other mineral oils are selected from a combination of one or more of coal liquefaction oil, oil sand oil and shale oil.

10. The method for regenerating a spent catalyst for a catalytic cracking reaction according to claim 8, characterized in that: The catalytic cracking reactor is a riser reactor, a fluidized bed reactor or a combination of the two.

11. The method for regenerating a spent catalyst for a catalytic cracking reaction according to any one of claims 1 to 10, characterized in that: The conditions of the catalytic cracking reaction include: reaction temperature of 450-700° C., reaction time of 1-10 seconds, and catalyst-oil ratio of (1-100):

1.

12. The method for regenerating a spent catalyst for a catalytic cracking reaction according to any one of claims 1 to 11, characterized in that: The flue gas is led out from the top of the regenerator and then separated to obtain CO product.

13. A catalyst regenerator suitable for a catalytic cracking unit, the regenerator comprising a first regeneration zone, a second regeneration zone, a carbon dioxide inlet, an oxygen-containing gas inlet, a catalyst to be regenerated inlet and a regenerated catalyst outlet, The first regeneration zone is configured to partially regenerate spent catalyst from a catalytic cracking reactor to produce a semi-regenerated catalyst. wherein the second regeneration zone is located below the first regenerator and is in fluid communication with the first regeneration zone, the second regeneration zone being configured such that when the semi-regenerated catalyst from the first regeneration zone passes downward through the second regeneration zone, it undergoes a second regeneration to produce a regenerated catalyst, The CO2 inlet is located at the lower part of the first regeneration zone and is used to input CO2 gas into the first regeneration zone. The oxygen-containing gas inlet is located at the lower part of the second regeneration zone and is used to input the oxygen-containing gas into the second regeneration zone. The spent catalyst inlet is configured to feed spent catalyst from the catalytic cracking reactor into the first regeneration zone, The regenerated catalyst outlet is configured to transport the regenerated catalyst out of the second regeneration zone, in, The first regeneration zone is a bubbling bed, and the second regeneration zone is a fast bed.

14. The catalyst regenerator according to claim 13, characterized in that: The regenerator also has a flue gas outlet and an energy recovery separation unit. The flue gas outlet is arranged at the top of the regenerator, and is used to discharge the flue gas from the first regeneration zone. The energy recovery and separation unit is in communication with the flue gas outlet and is used for recovering energy from the flue gas and separating the flue gas into CO products and other flue gas components.

15. The catalyst regenerator according to claim 13 or 14, characterized in that: The catalyst inlet of the regenerator is connected to the catalyst outlet of the catalytic cracking reactor. The regenerated catalyst outlet of the regenerator is communicated with the regenerated catalyst inlet of the catalytic cracking reactor.

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