A modeling method and device for catalytic cracking flue gas circulation regeneration system

Abstract

The present invention discloses a modeling method and device for a catalytic cracking flue gas circulation regeneration system, and belongs to the technical field of petrochemical industry. The modeling method includes: establishing a kinetic model of a charring reaction: establishing a charring reaction rate function regarding the molar concentration of coke and the molar concentration of oxygen; establishing a flue gas circulation regeneration system model: establishing a steady-state model of a regenerator according to a flue gas circulation regeneration process to calculate the contents of CO, CO2, H2O, and O2 in the regenerated flue gas and the coke content of the catalyst after regeneration; catalytic cracking flue gas circulation regeneration optimization: target optimization of the enrichment of carbon dioxide and the regeneration effect of the catalyst to be regenerated. The method can provide a kinetic model of the catalytic cracking regeneration process, predict the optimal oxygen flow rate and the regeneration flue gas circulation ratio, predict the regeneration flue gas composition, and the regeneration catalyst carbon content, and help operators optimize the regenerator operation, so as to achieve high regeneration efficiency and high-efficiency capture of carbon dioxide.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical engineering, and in particular to a modeling method and device for a catalytic cracking flue gas circulation regeneration system. Background Art

[0002] Human beings' numerous production and living behaviors continuously consume a large amount of carbon-containing fossil energy, and more than 60% of greenhouse gases produced by the consumption of carbon-containing fossil energy are carbon dioxide. According to the assessment report released by the Intergovernmental Panel on Climate Change (IPCC), the average global surface temperature has risen by 0.74℃ in the past 100 years, and may rise by 1.1-6.4℃ in the next 100 years. The scientific community generally believes that the emission of greenhouse gases such as carbon dioxide caused by the large-scale use of fossil fuels since the Industrial Revolution is the main cause of global warming.

[0003] To address the issue of global climate change, we must first start from the source by optimizing the industrial structure, improving energy efficiency and reducing carbon dioxide emissions; secondly, for carbon dioxide that must be emitted, its negative impact should be minimized through technical means such as capture, recycling and utilization.

[0004] The oil refining production process is the part of the petroleum and petrochemical industry that emits the most carbon dioxide, and the catalytic cracking unit is the unit with the highest carbon dioxide emissions among all types of oil refining units. Reducing carbon dioxide emissions from catalytic cracking units and improving the capture and recovery efficiency of carbon dioxide from catalytic cracking units are of great significance to "carbon capture and carbon neutrality."

[0005] The flue gas regeneration process replaces the traditional air (oxygen and nitrogen mixed gas) with a mixed gas of oxygen and carbon dioxide as the main air of the regenerator, which contacts the catalyst to be regenerated for charring and regeneration. This process does not require a complicated capture process. By optimizing the oxygen and circulating flue gas flow rates, high-purity carbon dioxide can be obtained, greatly improving the efficiency of carbon dioxide recovery and utilization. To optimize the oxygen and circulating flue gas flow rates, a flue gas regeneration system model needs to be established. Based on this model, the oxygen and circulating flue gas flow rates can be optimized for different regeneration conditions to obtain flue gas with high-purity carbon dioxide, while achieving better regeneration effects.

[0006] There is no research on the modeling of flue gas regeneration system.

[0007] In view of this, the present invention is proposed. Summary of the invention

[0008] One of the objectives of the present invention is to provide a modeling method for a catalytic cracking flue gas circulation regeneration system to solve the above technical problems.

[0009] A second object of the present invention is to provide a catalytic cracking flue gas circulation regeneration system modeling device corresponding to the above method.

[0010] A third object of the present invention is to provide an electronic device that can execute the steps in the above-mentioned catalytic cracking flue gas circulation regeneration system modeling method.

[0011] A fourth object of the present invention is to provide a readable storage medium storing a computer program that can execute the steps in the above-mentioned catalytic cracking flue gas circulation regeneration system modeling method.

[0012] This application can be implemented as follows:

[0013] In a first aspect, the present application provides a catalytic cracking flue gas circulation regeneration system modeling method, comprising the following steps:

[0014] Establish a charring reaction kinetic model: In the combustion reaction process, only carbon burning and hydrogen burning reactions are considered, and a charring reaction rate function related to the molar concentration of coke and the molar concentration of oxygen is established;

[0015] Establish a flue gas regeneration system model: According to the flue gas regeneration process, establish a steady-state model of the regenerator to calculate the contents of CO, CO2, H2O, O2 in the regenerated flue gas and the coke content of the catalyst after regeneration;

[0016] Optimization of catalytic cracking flue gas regeneration: Targeted optimization of carbon dioxide enrichment and regeneration of spent catalysts.

[0017] In a second aspect, the present application provides a catalytic cracking flue gas circulation regeneration system modeling device, the device comprising:

[0018] A charring reaction kinetic model module is established to establish a charring reaction rate function related to the molar concentration of coke and the molar concentration of oxygen;

[0019] Establish a flue gas regeneration system model module to establish a steady-state model of the regenerator according to the flue gas regeneration process to calculate the CO, CO2, H2O, O2 content in the regenerated flue gas and the coke content of the catalyst after regeneration;

[0020] The catalytic cracking flue gas regeneration optimization module is used to optimize the enrichment of carbon dioxide and the regeneration effect of the spent catalyst.

[0021] In a third aspect, the present application provides an electronic device including a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the steps in the catalytic cracking flue gas regeneration system modeling method of any of the aforementioned embodiments are performed.

[0022] In a fourth aspect, the present application provides a readable storage medium having a computer program stored thereon, which, when executed by a processor, runs the steps in the catalytic cracking flue gas circulation regeneration system modeling method as described in any of the aforementioned embodiments.

[0023] The beneficial effects of this application include:

[0024] The modeling method of the catalytic cracking flue gas circulation regeneration system proposed in the present application can provide a kinetic model of the catalytic cracking regeneration process, predict the optimal oxygen flow rate and regeneration flue gas circulation ratio, predict the regeneration flue gas composition and the carbon content of the regenerated catalyst, and help operators optimize the regenerator operation to achieve better regeneration efficiency and efficient capture of carbon dioxide. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 This is a schematic diagram of the process flow of the catalytic cracking flue gas recycling regeneration process in this application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0028] The following is a detailed description of the catalytic cracking flue gas recycling regeneration system modeling method and device provided in this application.

[0029] This application proposes a modeling method for a catalytic cracking flue gas circulation regeneration system, comprising the following steps:

[0030] S1. Establish a kinetic model of the charring reaction: During the combustion reaction, only carbon burning and hydrogen burning reactions are considered, and a charring reaction rate function related to the molar concentration of coke and the molar concentration of oxygen is established.

[0031] The coke attached to the surface of the deactivated catalyst is a mixture, which mainly contains carbon (C) and hydrogen (H). During the combustion reaction, carbon is oxidized to form CO and CO2, and hydrogen is oxidized to form H2O. When describing the kinetics of the coke burning reaction, elements such as nitrogen (N) and sulfur (S) in the coke are ignored, and only carbon burning and hydrogen burning reactions are considered. The coke burning reaction rate is a function of the molar concentration of coke and the molar concentration of oxygen.

[0032] For reference, the charring reaction rate function regarding the molar concentration of coke and the molar concentration of oxygen is established as follows:

[0033] Establish the kinetic reaction equation of the charring reaction:

[0034] ; ; ;

[0035] In the formula, r 1. r 2. r 3 represents the reaction rate when carbon is oxidized to CO, CO2 and H is oxidized to H2O, respectively, in units kmol Coke / ( m 3 catalyst ·s ); all reactions take place in the dense phase bed.

[0036] r 1. r 2. r 3 Calculated as follows:

[0037] ;

[0038] ;

[0039] ;

[0040] In the formula, k is the reaction rate constant, in units of m 3 / ( kmol·s ); s Indicates the molar ratio of generated CO2 and CO, in units kmol / kmol ; r c Indicates the density of catalyst particles in the dense phase region, unit kg / m 3 ; e c,D represents the volume fraction of dense-phase bed catalyst; w ck,DIndicates the coke content on the catalyst, unit kg Coke / kg catalyst; MW C Indicates the molar molecular mass of carbon, unit kg / kmol ; MW H Indicates the molar molecular mass of hydrogen, in units kg / kmol ; q is the molar ratio of hydrogen to carbon in coke; c i,j Indicated in j Gas composition in the area i The molar concentration, unit kmol / m 3 ; j The area corresponds to the dense bed D Area or corresponding dilute phase F Region, gas composition i Including CO, CO2, H2O, O2 or N2.

[0041] In the above formula, the value of σ can be calculated according to the following empirical formula:

[0042] ;

[0043] in, T Represents the dense phase bed temperature in the regenerator.

[0044] e c,D and e g,D It is calculated as follows:

[0045] ;

[0046] ;

[0047] In the formula, Ω RG It represents the cross-sectional area of ​​the dense phase bed of the regenerator; v g,D It represents the volume flow rate of gas in the dense phase, in units of m 3 / s， It is related to the main air flow entering the regenerator; e g,D Represents the volume fraction of mixed gas in the dense bed.

[0048] Reaction rate constant k According to the Arrhenius equation, it can be calculated as follows:

[0049] ;

[0050] Where R represents the ideal gas constant, 8.314 kJ / ( kmol·K ); k i0 and E i0 represent the pre-exponential factor and activation energy of the reaction respectively; T *Indicates reference regeneration temperature.

[0051] Furthermore, the CO generated by the carbon element reaction will continue to be oxidized to generate CO2, and this reaction will occur in both the dense phase bed and the dilute phase zone.

[0052] In a dense phase bed, the reaction equation and the reaction rate calculation formula are as follows:

[0053] ; ; ;

[0054] In the formula, c i,D is the molar concentration of gas in the dense phase; n i,D It represents the molar flow rate of each gas component in the dense phase, in units of kmol / s .

[0055] Since there is no scorching reaction in the freeboard zone, only CO oxidation reaction occurs, the CO oxidation reaction rate in the freeboard zone is as follows:

[0056] ; ;

[0057] In the formula, c i,F It represents the molar concentration of each gas component in the dilute phase, in units of kmol / m 3 ; n i,F It represents the molar flow rate of each gas component, in units of kmol / s ; v g,F It represents the volume flow rate of gas in the dilute phase, in units of m 3 / s .

[0058] S2. Establish a flue gas circulation regeneration system model: According to the flue gas circulation regeneration process, establish a steady-state model of the regenerator to calculate the CO, CO2, H2O, O2 content in the regenerated flue gas and the catalyst coke content after regeneration.

[0059] Catalytic cracking flue gas recycling regeneration process, the process flow diagram is as follows Figure 1As shown. A part of the flue gas generated by charring is circulated back to the main air inlet of the regenerator, mixed with high-purity oxygen in a certain molar ratio in the mixer, and then enters the regenerator as the main air for charring. The difference from the conventional regeneration process is that the flue gas in the conventional regeneration process passes through the regenerator once, while this process has flue gas circulation, and the modeling process of this process is somewhat different from that of the conventional process.

[0060] According to the charring reaction kinetics model and the process flow of the flue gas circulation regeneration system, a steady-state model of the regeneration system is established. The steady-state model of the regenerator is a set of ordinary differential equations, which can calculate the CO, CO2, H2O, O2 content of the regenerated flue gas and the carbon content of the regenerated catalyst.

[0061] The gases in the regenerator include CO, CO2, H2O, and O2. Material balance is performed on the gas in the dense bed, and the height of the dense bed is set constant to obtain the equation for the rate of change of the molar flow rate of each gas component along the axial direction, as shown below:

[0062] ;

[0063] ;

[0064] ;

[0065] ;

[0066] In the formula, Z D Indicates the height of dense bed, in m; Z = z / Z D , indicating that the bed z Dimensionless relative distance at the cross section.

[0067] The initial values ​​of the molar flow rates of each component are calculated as follows:

[0068] ; ; ; ;

[0069] In the formula, in represents the main air inlet of the regenerator, out represents the outlet of the regenerator, and α represents the flue gas circulation ratio.

[0070] For the gas in the dilute phase area, all of them come from the dense phase area, including CO, CO2, and H2O generated by the charring reaction. The molar flow rate of each component is calculated as follows:

[0071] ;

[0072] ;

[0073] ;

[0074] ;

[0075] In the formula, Z F Represents the height of the dilution zone, in meters.

[0076] According to the continuity of gas flow, the gas molar flow rate at the entrance of the dilute phase zone is equal to the gas molar flow rate at the exit of the dense phase zone. The calculation formula is as follows:

[0077] ; ; ; ;

[0078] In the above formula n (0) It represents the molar flow rate of each gas component at the entrance of the dilute phase zone, in units of kmol / s , n (ZD) It represents the molar flow rate of each gas component at the outlet of the dense phase zone, in units of kmol / s .

[0079] The ratio of each gas component in the flue gas is calculated by the following formula:

[0080] ;

[0081] In the formula, It represents the molar flow rate of each gas component in the regeneration flue gas, in units of kmol / s .

[0082] Based on the assumptions about the inside of the regenerator, the dense phase area of ​​the regenerator can be regarded as a continuous stirred tank reactor. The CO, CO2, and H2O in the regenerator are generated by the char burning reaction. The amount of char burning can be calculated by subtracting the CO, CO2, and H2O at the regenerator outlet from the CO, CO2, and H2O at the inlet.

[0083] Based on this, the coke content of the catalyst after regeneration is calculated as follows:

[0084] ;

[0085] ;

[0086] In the formula, F cat is the mass flow rate of the catalyst to be produced, in kg / s; W ck,ST It indicates the mass fraction of coke on the surface of spent catalyst.

[0087] S3. Catalytic cracking flue gas regeneration optimization: Target optimization of carbon dioxide enrichment and regeneration effect of spent catalyst.

[0088] The catalytic cracking flue gas recycling regeneration technology must achieve carbon dioxide enrichment, that is, the oxygen content and carbon monoxide content in the regenerated flue gas are as low as possible, and the carbon dioxide content is as high as possible, while at the same time ensuring a good regeneration effect of the spent catalyst. These goals are contradictory to a certain extent, so the technology needs to be optimized.

[0089] The optimization of catalytic cracking flue gas circulation regeneration in the present application includes the following steps: establishing an objective function.

[0090] It should be noted that, when using oxygen-poor regeneration technology, the oxygen content in the regenerated flue gas is generally lower than 0.1v%, but the carbon monoxide content is generally higher than 5v%. The flue gas is circulated to the regenerator inlet. Although oxygen recirculation is avoided, it is difficult to ensure that the carbon dioxide content of the outlet flue gas is not lower than 95v%. When using oxygen-enriched regeneration technology, the oxygen content in the regenerated flue gas is generally higher than 3v%, and the carbon monoxide content is generally lower than 0.5v%. When the flue gas is circulated to the regenerator inlet, the inlet oxygen flow rate will increase. If the initial inlet oxygen flow rate is not optimized, oxygen will be enriched in the regenerator, affecting the carbon dioxide concentration of the outlet flue gas. In order to enrich the outlet flue gas carbon dioxide to more than 95v%, it is necessary to optimize the initial oxygen flow rate at the regenerator inlet, the steady-state oxygen flow rate at the regenerator inlet, the initial flue gas circulation ratio, and the steady-state flue gas circulation ratio.

[0091] While ensuring that the carbon dioxide content at the flue gas outlet is enriched to more than 95v%, it is also necessary to ensure a good regeneration effect of the catalyst to be regenerated. This is a dual-objective optimization problem. The solution to a dual-objective optimization problem is generally a set of one or several sets of continuous solutions, and there is no single global optimal solution in a strict sense. However, industrial equipment can only operate according to one operating condition, and a relatively optimal solution needs to be obtained. Therefore, it is necessary to transform the dual-objective optimization problem into a single-objective optimization problem.

[0092] The proportion of carbon dioxide in the regeneration flue gas in both targets The higher the better. Regenerated catalyst carbon setting As long as it is reduced to below 0.05w%, efficient regeneration of the spent catalyst is achieved without the need for further reduction.

[0093] Based on this, this application proposes the following objective function:

[0094] ;

[0095] Optimize the regeneration operating conditions so that the objective function The value of is as small as possible, that is, the carbon dioxide ratio As high as possible. Among them, the regenerator operating conditions that can be optimized include the initial oxygen flow rate at the regenerator inlet , steady-state oxygen flow rate at the regenerator inlet , initial flue gas circulation ratio α 0 and flue gas steady-state circulation ratio α .

[0096] In some optional embodiments, the optimization includes: setting the initial oxygen flow rate at the regenerator inlet and initial flue gas circulation ratio α 0 is a fixed value, which is the steady-state flow rate of oxygen at the regenerator inlet. and flue gas steady-state circulation ratio α Make optimizations.

[0097] Set the initial operation of the regenerator to oxygen-rich regeneration, and the initial oxygen flow rate at the regenerator inlet , initial flue gas circulation ratio α 0=0.8.

[0098] Regenerator inlet oxygen steady state flow The optimization interval is set according to the regenerated catalyst circulation amount and regenerated catalyst carbon content of the catalytic cracking unit. , flue gas circulation ratio α The optimization interval is .

[0099] In addition, the present application also provides a catalytic cracking flue gas circulation regeneration system modeling device corresponding to the above modeling method, the device comprising:

[0100] A charring reaction kinetic model module is established to establish a charring reaction rate function related to the molar concentration of coke and the molar concentration of oxygen;

[0101] Establish a flue gas regeneration system model module to establish a steady-state model of the regenerator according to the flue gas regeneration process to calculate the CO, CO2, H2O, O2 content in the regenerated flue gas and the coke content of the catalyst after regeneration;

[0102] The catalytic cracking flue gas regeneration optimization module is used to optimize the enrichment of carbon dioxide and the regeneration effect of the spent catalyst.

[0103] In addition, the present application also provides an electronic device, which may include a catalytic cracking flue gas circulation regeneration system modeling device, a memory, a storage controller, a processor, a peripheral interface, an input and output unit, an audio unit, and a display unit, etc. The connection relationship and specific application method of the structure contained in the above electronic device can refer to the prior art, and will not be described in detail here.

[0104] In addition, the present application also provides a readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned catalytic cracking flue gas circulation regeneration system modeling method are executed.

[0105] In a second aspect, the present application provides a catalytic cracking flue gas circulation regeneration system modeling device, the device comprising:

[0106] A charring reaction kinetic model module is established to establish a charring reaction rate function related to the molar concentration of coke and the molar concentration of oxygen;

[0107] Establish a flue gas regeneration system model module to establish a steady-state model of the regenerator according to the flue gas regeneration process to calculate the CO, CO2, H2O, O2 content in the regenerated flue gas and the coke content of the catalyst after regeneration;

[0108] The catalytic cracking flue gas regeneration optimization module is used to optimize the enrichment of carbon dioxide and the regeneration effect of the spent catalyst.

[0109] In a third aspect, the present application provides an electronic device including a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the steps in the catalytic cracking flue gas regeneration system modeling method of any of the aforementioned embodiments are performed.

[0110] In a fourth aspect, the present application provides a readable storage medium having a computer program stored thereon, which, when executed by a processor, runs the steps in the catalytic cracking flue gas circulation regeneration system modeling method as described in any of the aforementioned embodiments.

[0111] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0112] Example 1

[0113] The catalytic cracking flue gas regeneration system modeling method provided in this application is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The optimized oxygen flow rate is 4.48m 3 / s, the optimized circulation ratio is 0.73, and the regenerated flue gas composition and regenerated catalyst carbon content are shown in Table 1.

[0114] Comparative Example 1

[0115] The present invention is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The oxygen flow rate is 4.48m 3 / s, the circulation ratio is 0.8, and the regeneration flue gas composition and regeneration catalyst carbon content are shown in Table 1.

[0116] That is, the difference between this comparative example and Example 1 is that the circulation ratio of the flue gas is different, and the oxygen circulation ratio of this comparative example is higher than that of Example 1.

[0117] Comparative Example 2

[0118] The present invention is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The oxygen flow rate is 4.48m 3 / s, the circulation ratio is 0.7, and the regeneration flue gas composition and regeneration catalyst carbon content are shown in Table 1.

[0119] That is, the difference between this comparative example and Example 1 is that the circulation ratio of the flue gas is different, and the oxygen circulation ratio of this comparative example is lower than that of Example 1.

[0120] Comparative Example 3

[0121] The present invention is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The oxygen flow rate is 5.00m 3 / s, the circulation ratio is 0.73, and the regeneration flue gas composition and regeneration catalyst carbon content are shown in Table 1.

[0122] That is, the difference between this comparative example and Example 1 is that the oxygen flow rate is different, and the oxygen flow rate of this comparative example is higher than that of Example 1.

[0123] Comparative Example 4

[0124] The present invention is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The oxygen flow rate is 4.00m 3 / s, the circulation ratio is 0.73, and the regeneration flue gas composition and regeneration catalyst carbon content are shown in Table 1.

[0125] That is, the difference between this comparative example and Example 1 is that the oxygen flow rate is different, and the oxygen flow rate of this comparative example is lower than that of Example 1.

[0126] Comparative Example 5

[0127] The present invention is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The oxygen flow rate is 4.48m 3 / s, the circulation ratio is 1.0, and the regeneration flue gas composition and regeneration catalyst carbon content are shown in Table 1.

[0128] That is, the difference between this comparative example and Example 1 is that the circulation ratio of the flue gas is different, and the oxygen circulation ratio of this comparative example is higher than that of Example 1.

[0129] Comparative Example 6

[0130] The present invention is used to optimize the oxygen flow rate and circulation ratio, so that the carbon dioxide content in the regenerated flue gas reaches more than 95v%, and the carbon content of the regenerated catalyst is reduced to less than 0.05w%. The flow rate of the catalyst to be regenerated is set to 210kg / s, the carbon content of the catalyst to be regenerated is 1w%, the dense phase temperature of the regenerator is 690℃, and the top pressure of the regenerator is 0.2MPa. The oxygen flow rate is 4.48m 3 / s, the circulation ratio is 0.4, and the regeneration flue gas composition and regeneration catalyst carbon content are shown in Table 1.

[0131] That is, the difference between this comparative example and Example 1 is that the circulation ratio of the flue gas is different, and the oxygen circulation ratio of this comparative example is lower than that of Example 1.

[0132] Table 1 Flue gas composition

[0133]

[0134] Comparing the results in Table 1, it can be seen that under optimized conditions, the carbon dioxide content in the regeneration flue gas can reach more than 95v%, and the carbon content of the regeneration agent can be reduced to less than 0.05w%.

[0135] Under the optimized oxygen flow rate, the regeneration flue gas circulation ratio increases, the carbon dioxide content in the flue gas decreases, and the regeneration agent carbon content increases. Under the optimized oxygen flow rate, the regeneration flue gas circulation ratio decreases, the carbon dioxide content in the flue gas decreases, and the regeneration agent carbon content decreases. Under the optimized regeneration flue gas circulation ratio, the oxygen flow rate is increased, the carbon dioxide content in the flue gas decreases, and the regeneration agent carbon content decreases. Under the optimized regeneration flue gas circulation ratio, the oxygen flow rate is reduced, the carbon dioxide content in the flue gas decreases, and the regeneration agent carbon content increases. Only under the optimized operating conditions provided in Example 1 can the optimal regeneration result be obtained.

[0136] In summary, the catalytic cracking flue gas circulation regeneration system modeling method proposed in this application can provide a kinetic model of the catalytic cracking regeneration process, predict the optimal oxygen flow rate and regeneration flue gas circulation ratio, predict the regeneration flue gas composition and regeneration catalyst carbon determination, and help operators optimize the regenerator operation to achieve better regeneration efficiency while realizing efficient capture of carbon dioxide.

[0137] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A modeling method for a catalytic cracking flue gas regeneration system, characterized in that: The following steps are involved: Establish a char burning reaction kinetic model: In the combustion reaction process, only carbon burning and hydrogen burning reactions are considered, and a char burning reaction rate function related to the molar concentration of coke and the molar concentration of oxygen is established; Establish a flue gas regeneration system model: According to the flue gas regeneration process, establish a steady-state model of the regenerator to calculate the contents of CO, CO2, H2O, O2 in the regenerated flue gas and the coke content of the catalyst after regeneration; Optimization of catalytic cracking flue gas regeneration: Target optimization of carbon dioxide enrichment and regeneration effect of spent catalyst; The function of the charring reaction rate on the char molar concentration and oxygen molar concentration is established by: The reaction between carbon and hydrogen in the dense bed is as follows: ； ； ； In the formula, r 1. r 2. r 3 represents the reaction rate when carbon is oxidized to CO, CO2 and H is oxidized to H2O, respectively, in units kmol Coke / ( m 3 catalyst ·s ) ; r 1. r 2. r 3 Calculated as follows: ； ； ； In the formula, k is the reaction rate constant, in units of m 3 / ( kmol·s ); σ Indicates the molar ratio of generated CO2 and CO, in units kmol / kmol ; ρ c It represents the density of catalyst particles in the dense phase region, in units of kg / m 3 ; ε c,D represents the volume fraction of dense-phase bed catalyst; w ck,D Indicates the coke content on the catalyst, unit kg Coke / kg catalyst; MW C Indicates the molar molecular mass of carbon, unit kg / kmol ; MW H Indicates the molar molecular mass of hydrogen, unit kg / kmol ; q is the molar ratio of hydrogen to carbon in coke; c i,j Indicated in j Gas composition in the area i The molar concentration, unit kmol / m 3 ; j The area corresponds to the dense bed D Area or corresponding dilute phase F Region, the gas composition i including CO, CO2, H2O, O2 or N2; In a dense phase bed, carbon generates CO and then is oxidized to generate CO2. The corresponding reaction equation and reaction rate calculation formula are as follows: ； ； ； In the formula, c i,D is the molar concentration of gas in the dense phase; n i,D It represents the molar flow rate of each gas component in the dense phase, in units of kmol / s ; v g,D It represents the volume flow rate of gas in the dense phase, in units of m 3 / s ; There is no scorching reaction in the dilute phase zone, only CO oxidation reaction. The CO oxidation reaction rate in the dilute phase zone is as follows: ； ； In the formula, c i,F It represents the molar concentration of each gas component in the dilute phase, in units of kmol / m 3 ; n i,F It represents the molar flow rate of each gas component, in units of kmol / s ; v g,F It represents the volume flow rate of gas in the dilute phase, in units of m 3 / s ; σ is taken as follows: ； T Display regenerator inner dense phase bed temperature; ε c,D and ε g,D It is calculated as follows: ； ； In the formula, Ω RG It represents the cross-sectional area of ​​the dense phase bed of the regenerator; ε g,D It represents the volume fraction of mixed gas in dense bed; Reaction rate constant k i It is calculated as follows: ； Where R represents the ideal gas constant, 8.314 kJ / ( kmol·K ); k i0 and E i0 represent the pre-exponential factor and activation energy of the reaction respectively; T *Indicates reference regeneration temperature; The establishment of the regenerator steady-state model includes the following steps: The material balance of the gas in the dense bed is performed, and the height of the dense bed is set to be constant. The equation for the rate of change of the molar flow rate of each gas component along the axial direction is obtained as follows: ； ； ； ； In the formula, Z D Indicates the height of dense bed, in m; Z = z / Z D , indicating that the bed z Dimensionless relative distance at the cross section; The initial values ​​of the molar flow rates of each component are calculated as follows: ； ； ； ； In the formula, in Indicates the main air inlet of the regenerator. out Represents the regenerator outlet, α Indicates the flue gas circulation ratio; For the gas in the freeboard region, the molar flow rate of each component is calculated as follows: ； ； ； ； In the formula, Z F Indicates the height of the dilute phase zone, in m; According to the continuity of gas flow, the gas molar flow rate at the entrance of the dilute phase zone is equal to the gas molar flow rate at the exit of the dense phase zone. The calculation formula is as follows: ； ； ； ； In the above formula n (0) It represents the molar flow rate of each gas component at the entrance of the dilute phase zone, in units of kmol / s , n (ZD) It represents the molar flow rate of each gas component at the outlet of the dense phase zone, in units of kmol / s ; The ratio of each gas component in the flue gas is calculated by the following formula: ； In the formula, It represents the molar flow rate of each gas component in the regeneration flue gas, in units of kmol / s ; The calculation formula of the coke content of the catalyst after regeneration is as follows: ； ； In the formula, F cat is the mass flow rate of the catalyst to be produced, in kg / s; W ck,ST Indicates the mass fraction of coke on the surface of spent catalyst; The optimization of catalytic cracking flue gas regeneration cycle includes the following steps: Establish the objective function: ； Optimize the regeneration operating conditions, where the regenerator operating conditions that can be optimized include the initial oxygen flow rate at the regenerator inlet , steady-state oxygen flow rate at the regenerator inlet , initial flue gas circulation ratio α 0 and flue gas steady-state circulation ratio α ; Optimization includes: Setting the initial oxygen flow rate at the regenerator inlet and initial flue gas circulation ratio α 0 is a fixed value, which is the steady-state flow rate of oxygen at the regenerator inlet. and flue gas steady-state circulation ratio α Optimize Set the initial operation of the regenerator to oxygen-rich regeneration, and the initial oxygen flow rate at the regenerator inlet , initial flue gas circulation ratio α 0=0.8; Regenerator inlet oxygen steady state flow The optimization interval is set according to the regenerated catalyst circulation amount and regenerated catalyst carbon content of the catalytic cracking unit. , flue gas circulation ratio α The optimization interval is .

2. A catalytic cracking flue gas regeneration system modeling device, characterized in that: The device comprises: A charring reaction kinetic model module is established to establish a charring reaction rate function related to the molar concentration of coke and the molar concentration of oxygen; Establish a flue gas regeneration system model module to establish a steady-state model of the regenerator according to the flue gas regeneration process to calculate the CO, CO2, H2O, O2 content in the regenerated flue gas and the coke content of the catalyst after regeneration; The catalytic cracking flue gas regeneration optimization module is used to optimize the enrichment of carbon dioxide and the regeneration effect of the spent catalyst.

3. An electronic device, characterized in that: It comprises a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the steps in the catalytic cracking flue gas circulation regeneration system modeling method as claimed in claim 1 are executed.

4. A readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, the steps of the catalytic cracking flue gas circulation regeneration system modeling method as claimed in claim 1 are executed.

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