Coking tower switching control method, device and equipment in delayed coking and storage medium

Abstract

The invention discloses a coke tower switching control method, device and equipment in delayed coking and a storage medium. The method comprises the following steps: respectively generating a three-dimensional thermodynamic model when each coke tower is in a coke forming state, and meshing the three-dimensional thermodynamic models; according to the three-dimensional thermodynamic model, a lumped kinetics model is introduced, the physical significance of the adhesion phenomenon of the free coke and the wall surface in the coking process is mathematized, and reaction kinetics and stress analysis related to the free coke in the coking process are further defined by calculating the change condition of multiphase flow in a coke tower. Therefore, the coking data in the coke tower can be quickly and accurately acquired by acquiring the theoretical coking amount of reaction kinetics, analyzing the adhesion force of the free coke to the wall surface, the interphase drag force of gas, liquid and solid, the gravity and the shear stress of the wall surface, and blowing the flowing fluid; therefore, the coke towers can be timely switched under the condition that the pyrolysis space of the coke towers is fully utilized, so that the treatment efficiency of the device is effectively improved, and the redundant waste of the treatment capacity of the coke towers is reduced.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology, and in particular to a coke drum switching control method, device, equipment and storage medium in delayed coking. Background Art

[0002] Delayed coking, a type of thermal cracking process, primarily consists of two core pieces of equipment: a heating furnace and a coke drum. The heating furnace is primarily responsible for rapidly heating the feedstock. Once the feedstock reaches the reaction temperature (typically around 500°C) but has not yet coked, it is quickly fed into the coke drum. This delays the thermal cracking and condensation reactions until they occur in the drum, producing coke and light oil products.

[0003] The coke tower will switch between the two working states of coking and decoking; after the coke tower connected to the heating furnace completes the coking process, it will enter the decoking process. At this time, the heating furnace will switch to connect to another coke tower that has completed the decoking process. In this way, the continuity of the delayed coking process can be maintained through the coke tower switching control.

[0004] Since the interior of the coke tower is closed, the coke height cannot be observed directly. Although the gas-liquid-solid three-phase products can be monitored by installing detectors on the tower wall, accurate judgment cannot be made due to the limitation of the number and sensitivity of the instruments. In order to ensure the stable operation of the process, in the actual production process, the design of the coke tower will adopt an over-design method, making the capacity of the coke tower larger than the actual need, to ensure that it will not be blocked during the set coke tower switching cycle; for example, the coke tower will not be blocked even if it works continuously for 28 hours or 30 hours. In this way, it can be guaranteed that it will not be blocked during the 24-hour coke tower switching cycle.

[0005] After research, the inventors found that the existing technology has at least the following defects:

[0006] The processing capacity of the delayed coking unit cannot be fully utilized.

[0007] The information disclosed in this background technology section is only intended to increase understanding of the overall background of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes prior art already known to those skilled in the art. Summary of the Invention

[0008] The purpose of the present invention is to fully utilize the processing capacity of a delayed coking device.

[0009] The present invention provides a coke drum switching control method in delayed coking, comprising the steps of:

[0010] S11, pre-generating a three-dimensional thermodynamic model of each coke drum in a coking state based on the reactor wall, the residual oil feed inlet, and the light component outlet of the coke drum, and performing meshing;

[0011] S12. For a target coke drum in a coking state, obtaining preset operating parameters of the target coke drum in real time as input parameters of its corresponding three-dimensional thermodynamic model; the input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure, and multiphase flow interphase drag;

[0012] S13, using a preset time step as a calculation cycle, and calculating the simulation results of the three-dimensional thermodynamic model according to the input parameters; the results include a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution;

[0013] S14, determining a grid whose volume fraction distribution predicted value of the solid phase main component is greater than a preset fraction threshold as a target grid; and calculating the free coke adhesion force of the target grid area, as well as the gravity and shear stress of the solid phase main component in the target grid area;

[0014] S15, judging whether the angle between the resultant force direction of the components of the target grid in the radial direction of the reactor and the direction of the normal line of the wall section and the radial direction of the reactor is greater than 90° based on the free coke adhesion, gravity and shear stress; if so, determining the target grid as a coking grid;

[0015] S16, respectively calculating the coke increment of each coking grid after one time step, and calculating the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid;

[0016] S17, respectively calculating the gas-solid phase drag, liquid-solid phase drag, gas-liquid phase drag and convection diffusion of each coking grid after one time step, and recording their sum as the flow purge amount after one time step;

[0017] S18, calculating the difference between the predicted amount of coke adhesion and the flow purge amount to obtain the predicted coke inventory of the coking grid after one time step;

[0018] S19. Determine whether the target coke drum exceeds the coking critical value based on the predicted coke inventory. If so, switch the coke drum and set the current state of the target coke drum to decoking.

[0019] In another aspect of the present invention, a coke drum switching control device in a delayed coking process is provided, comprising:

[0020] A model presetting unit is used to pre-generate a three-dimensional thermodynamic model of each coke drum in a coking state according to the reactor wall, residual oil feed inlet and light component outlet of the coke drum and perform meshing;

[0021] a parameter determination unit for obtaining, in real time, preset operating parameters of a target coke drum in a coking state as input parameters for a corresponding three-dimensional thermodynamic model; the input parameters including: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure, and multiphase flow interphase drag;

[0022] a simulation calculation unit, configured to calculate a simulation result of the three-dimensional thermodynamic model based on the input parameters with a preset time step as a calculation period; the result including a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution;

[0023] a target grid determination unit, configured to determine a grid having a volume fraction distribution prediction value of a solid phase main component greater than a preset fraction threshold as a target grid; and respectively calculate the free coke adhesion force of the target grid area, and the gravity and shear stress of the solid phase main component in the target grid area;

[0024] a coking grid judging unit, configured to judge, based on the free coke adhesion, gravity, and shear stress, whether the angle between the resultant force direction of the target grid components in the reactor radial direction and the direction of the normal line of the wall section and the reactor radial direction is greater than 90°; if so, determining the target grid as a coking grid;

[0025] a coke adhesion prediction unit, configured to respectively calculate the coke increment of each coking grid after one time step, and calculate the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid;

[0026] a purge volume calculation unit for respectively calculating the gas-solid phase drag, the liquid-solid phase drag, the gas-liquid phase drag, and the convection diffusion of each of the coking grids after one time step, and recording their sum as the flow purge volume after one time step;

[0027] A coke inventory prediction unit, configured to calculate the predicted coke inventory of the coking grid after one time step by using the difference between the predicted coke adhesion amount and the flow purge amount;

[0028] A control instruction generating unit is used to determine whether the target coke drum exceeds the coking critical value based on the predicted coke inventory. If so, the coke drum is switched and the current state of the target coke drum is set to decoking.

[0029] In another aspect of the present invention, there is also provided a coke drum switching control device in a delayed coking process, comprising:

[0030] memory for storing computer programs;

[0031] A processor is used to call and execute the computer program to implement each step of the coke drum switching control method in delayed coking as described in any one of the above items.

[0032] On the other hand, a storage medium is provided on which a computer program is stored. When the computer program is executed by a processor, each step of the coke drum switching control method in delayed coking is implemented as described in any one of the above items.

[0033] The coke drum switching control device in the delayed coking process includes a computer program stored on a medium, and the computer program includes program instructions. When the program instructions are executed by a computer, the computer executes the methods described in the above aspects and achieves the same technical effects.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] After research, the inventors discovered that the coke drum and heating furnace in delayed coking are the core equipment of the entire process. However, the existing technology lacks a method to accurately measure the degree of coking. The only way to roughly calculate the coking height is by installing wall detectors or increasing the redundancy of the coke drum, lacking a means of precise quantification. To ensure stable process operation, the design of the coke drum in delayed coking is often based on industrial amplification of processing capacity and a fixed coking cycle. In this case, the redundancy of the coke drum is relatively high. This, in turn, wastes the pyrolysis space in the coke drum, reducing the processing capacity and coking efficiency of coke drums of the same size.

[0036] Based on the above findings, the present invention first established a precise coking prediction method. This method mathematically quantifies the physical significance of the adhesion of free coke to the wall during the coking process by introducing a lumped kinetic model. By calculating the changes in multiphase flow within the coke drum, the reaction kinetics and force analysis related to free coke during the coking process are further clarified. This method, by obtaining the theoretical coking amount from the reaction kinetics, analyzing the adhesion of free coke to the wall, the drag force between the gas-liquid-solid phases, gravity, and the wall shear stress, and combining it with fluid flow purging, can quickly and accurately obtain coking data within the coke drum.

[0037] As can be seen from the above, in the present invention, a three-dimensional thermodynamic model is generated according to each coke tower, and the volume fraction prediction value of the gas-liquid-solid three-phase components and the temperature distribution prediction value are predicted; further, the coke inventory in the coke tower after the preset time is accurately predicted. In this way, the coke tower can be switched in time while fully utilizing the pyrolysis space of the coke tower, thereby effectively improving the processing efficiency of the device and reducing the redundant waste of the coke tower processing capacity.

[0038] In addition, since the present invention can maximize the use of the pyrolysis space of the coke drum, the coke generation time of the coke drum is extended, thereby reducing the number of switching times of the coke drum and saving labor costs.

[0039] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and to implement it according to the contents of the specification, and to make the above and other purposes, technical features and advantages of the present invention easier to understand, one or more preferred embodiments are listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 This is a step diagram of the coke drum switching control method in the delayed coking process of the present invention;

[0042] Figure 2 It is a schematic structural diagram of the reaction pathways in the fifteen lumped kinetic models described in the present invention;

[0043] Figure 3 It is a structural schematic diagram of the coke drum switching control device in the delayed coking process of the present invention;

[0044] Figure 4 It is a structural diagram of the coke drum switching control equipment in the delayed coking process described in the present invention. DETAILED DESCRIPTION

[0045] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0046] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0047] In this document, the terms "first", "second", etc. are used to distinguish two different elements or parts, and are not used to limit specific positions or relative relationships. In other words, in some embodiments, the terms "first", "second", etc. can also be interchangeable with each other.

[0048] Example 1

[0049] In order to effectively improve the processing efficiency of the device and reduce the redundant waste of coke tower processing capacity, such as Figure 1 As shown, in an embodiment of the present invention, a method for controlling the switching of coke drums in delayed coking is provided, comprising the steps of:

[0050] S11, pre-generating a three-dimensional thermodynamic model of each coke drum in a coking state based on the reactor wall, the residual oil feed inlet, and the light component outlet of the coke drum, and performing meshing;

[0051] In the delayed coking process, a heating furnace can be alternately connected to two or more coke drums. That is, when the working heating furnace is connected to a coke drum, the coke drum enters the coking state, and the other coke drums are in the decoking state; when the coke making process of the coke drum connected to the heating furnace is completed, the heating furnace will be connected to another coke drum through the switching of the coke drum and the newly connected coke drum will enter the coking state, and the coke drum that has just completed the coking state will enter the decoking state.

[0052] In the embodiment of the present invention, based on the actual operating conditions of each coke drum (including the reactor wall, the residual oil feed inlet, and the light component outlet), a three-dimensional thermodynamic model corresponding to each coke drum in the coking state is generated in advance and gridded. The specific method may include:

[0053] Assume that the cavity volume of the three-dimensional thermodynamic model of the coke drum is V and the height is H; the three-dimensional thermodynamic model after gridding has α grid units and is stored in the set Data_α, where the temperature of the i-th grid unit belonging to the set Data_α is T i , the amount of coke is Coke i ;

[0054] In practical applications, the grid of the three-dimensional thermodynamic model in the embodiment of the present invention can specifically be one or more of a tetrahedral grid, a hexahedral grid, a pyramid grid, a wedge grid and a polyhedral grid; its calibration method can specifically be one or more of general physics, fluid dynamics, plasma and semiconductor.

[0055] S12. For a target coke drum in a coking state, obtaining preset operating parameters of the target coke drum in real time as input parameters of its corresponding three-dimensional thermodynamic model; the input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure, and multiphase flow interphase drag;

[0056] In the embodiment of the present invention, the coke drum connected to the heating furnace and entering the coking state is called the target coke drum.

[0057] When the coke drum enters the coking state, the preset operating parameters of the target coke drum are obtained in real time as the input parameters of its corresponding three-dimensional thermodynamic model; in this way, the three-dimensional thermodynamic model can be used to simulate the coke distribution and temperature distribution inside the target coke drum during the coking process.

[0058] S13, using a preset time step as a calculation cycle, and calculating the simulation results of the three-dimensional thermodynamic model according to the input parameters; the results include a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution;

[0059] In an embodiment of the present invention, the simulation results of the three-dimensional thermodynamic model obtained by calculating the input parameters are periodic, that is, a calculation is performed every time step; in practical applications, the value of the time step can be determined based on the actual computing power of the computer and the experience of those skilled in the art, and is not specifically limited here.

[0060] In an embodiment of the present invention, the purpose of obtaining the simulation results of the three-dimensional model based on the input parameters is to obtain the volume fraction prediction value and temperature prediction value of the gas, liquid and solid three phases in the coke drum at the next time step under the current time step, that is, to predict the volume fraction and temperature of the gas, liquid and solid three phases in the coke drum.

[0061] S14, determining a grid whose volume fraction distribution predicted value of the solid phase main component is greater than a preset fraction threshold as a target grid; and calculating the free coke adhesion force of the target grid area, as well as the gravity and shear stress of the solid phase main component in the target grid area;

[0062] In order to reduce the amount of calculation and improve the calculation response rate, before calculating the spatial position and content of the wall-adhering coke in the coke drum, the grid cells that do not contain the main solid components or have a very low content of the main solid components can be eliminated to reduce unnecessary calculations.

[0063] Preferably, in an embodiment of the present invention, the preset fraction threshold can be set to 0.5%. In this way, the grids whose predicted volume fraction distribution value of the solid phase main component is greater than the preset fraction threshold can be determined as target grids, and other grids do not need to participate in subsequent calculations.

[0064] In the embodiment of the present invention, the free coke adhesion in the target grid area, as well as the gravity and shear stress of the solid main component are calculated, specifically, as follows:

[0065] A traversal approach is used to determine whether the free coke formed in each grid can maintain its adhesion to the reactor wall by overcoming gravity and shear stress through its own adhesion or relying on it. Specifically, for each grid, a temperature prediction for the next time step is obtained. Then, based on the physicochemical properties of the free coke formed by the material and the functional relationship between the free coke adhesion and temperature, the adhesion force vector for the free coke at the next time step is determined. Similarly, the gravity and shear stress vectors for the free coke at the next time step are also obtained.

[0066] S15, judging whether the angle between the resultant force direction of the components of the target grid in the radial direction of the reactor and the direction of the normal line of the wall section and the radial direction of the reactor is greater than 90° based on the free coke adhesion, gravity and shear stress; if so, determining the target grid as a coking grid;

[0067] In order to determine whether the main solid components in the target grid area can adhere to the wall of the coke drum, mechanical analysis is used to perform a force analysis on the radial cross-section of the tubular reactor, that is, the angle between the radial component of the combined force of adhesion, gravity and shear stress and the normal direction of the wall section (with the geometric center of the tubular reactor as the vector direction) is obtained. If it is greater than 90°, the target grid is determined as a coking grid (the coking grid is stored in the data set Coked) and marked as a coking space.

[0068] S16, respectively calculating the coke increment of each coking grid after one time step, and calculating the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid;

[0069] Traverse the grids in the data set Coked. For each grid, according to the previous steps, combined with the lumped kinetics and reaction mechanism of the current process, calculate the coke increment of the current grid area at the next time step, and obtain the current coke stock in the data set Coked at the current time step. Then, record the sum of the two as the predicted coke adhesion amount Stock at the next time step.

[0070] S17, respectively calculating the gas-solid phase drag, liquid-solid phase drag, gas-liquid phase drag and convection diffusion of each coking grid after one time step, and recording their sum as the flow purge amount after one time step;

[0071] Next, calculate the drag between the gas-solid phase, the drag between the liquid-solid phase, and the drag between the gas-liquid phase in the current grid at the next time step, as well as the convection and diffusion amount of the current grid at the next time step. Then, record their sum as the flow sweep amount Sweep in the next time step;

[0072] When calculating the drag force between gas and solid phases, the energy minimum multiscale model can be used. The model equations include:

[0073]

[0074] Among them, F gs is the drag force between gas and solid phases, Re is the Reynolds coefficient, ε is the average void ratio, d p is the particle diameter, ρ is the average density, u g is the superficial velocity of the gas, u p is the particle superficial velocity.

[0075] When calculating the drag force between liquid and solid phases, the Schiller-Naumann uniform drag model can be used. The model equation includes:

[0076]

[0077]

[0078] Among them, F ls is the drag force between liquid and solid phases, C D，ls is the liquid-solid two-phase drag coefficient, and u is the fluid superficial velocity.

[0079] When calculating the drag force between gas and liquid phases, the Grace drag model can be used. The model equations include:

[0080]

[0081]

[0082] Among them, F gl is the drag force between gas and liquid phases, C D，gl is the drag coefficient of the gas-liquid two-phase, g is the acceleration due to gravity, d b is the bubble diameter, ρ l is the liquid density, ρ g is the gas phase density, u T is the terminal velocity.

[0083] After obtaining the drag between the gas-solid phase, the drag between the liquid-solid phase, and the drag between the gas-liquid phase through the above method, the convection and diffusion amount of the current grid area at the next time step is calculated, and then their sum is recorded as the flow sweep amount Sweep at the next time step.

[0084] S18, calculating the difference between the predicted amount of coke adhesion and the flow purge amount to obtain the predicted coke inventory of the coking grid after one time step;

[0085] To estimate the final coke inventory at the next time step, the present embodiment requires comparing the predicted coke adhesion quantity (Stock) with the flow purge quantity (Sweep) from the above step. If the predicted coke adhesion quantity (Stock) is less than the flow purge quantity (Sweep), it indicates that insufficient coke will adhere to the wall surface for that grid at the next time step. If the predicted coke adhesion quantity (Stock) is greater than the flow purge quantity (Sweep), the flow purge quantity (Sweep) is deducted from the predicted coke adhesion quantity (Stock) to update the data in the data set Coked. This data is the final predicted coke inventory for that grid at the next time step.

[0086] S19. Determine whether the target coke drum exceeds the coking critical value based on the predicted coke inventory. If so, switch the coke drum and set the current state of the target coke drum to decoking.

[0087] In an embodiment of the present invention, it is necessary to determine whether any grid unit in the coke drum will exceed the coking critical value at the next time step to determine the timing of switching the coke drum, that is, if any grid unit in the coke drum will exceed the coking critical value at the next time step, then the coke drum must be switched; in an embodiment of the present invention, the coking critical value refers to the maximum value of the achievable designed coking height, for example, if the designed coking height of the coke drum is 5m, then when the grid units above 5m are predicted to produce coke, it is considered that the coking critical value is reached.

[0088] In the embodiment of the present invention, if the total content of all solid phases in the coke drum does not exceed the theoretical coking rate of the slag-reduced raw material, and the height of the coking zone is not greater than the designed coking height of the coke drum, it is deemed not to exceed.

[0089] It should be further explained that delayed coking is a relatively downstream process in the entire petrochemical process, so the raw materials of the process are uncertain. It is generally believed that the composition of the four components of saturated hydrocarbons, aromatic hydrocarbons, resins and asphaltenes in the residual oil will affect the products of delayed coking, especially the amount of coke. Therefore, in the embodiment of the present invention, the lumped kinetic equation is introduced to facilitate the four components to be treated as four lumps. In this way, when the raw materials change greatly, the rate of each reaction path can be accurately calculated through lumped kinetics, so as to accurately know the amount of coke.

[0090] The lumped kinetic model comprehensively considers the effects of the four raw material components on coking, providing a more comprehensive description of the coking process and a prediction of the coking degree. Compared to traditional empirical models or formulas, the lumped kinetic model offers greater precision and reliability, providing more accurate results.

[0091] Combined with the characteristics of raw materials in delayed coking and considering the impact on the coke yield, fifteen lumped kinetic models (including: lumps (A), (B) (C) (D... (O)) are established in the patent of this invention, in which the four components of the raw materials, saturated hydrocarbons (A), aromatic hydrocarbons (B), resins (C) and asphaltenes (D), are respectively used as four lumps. This is because delayed coking is a relatively downstream process in the entire petrochemical process, and the composition of the raw materials is affected by the upstream process and is unstable. Therefore, it is necessary to judge the impact on the coke yield based on the content of the four components of the raw material residue oil.

[0092] When the raw material residue oil passes through the delayed coking unit, the liquid products generated include coking gasoline (E), coking diesel (F), coking light wax (G), and coking heavy wax (H), so these four are also regarded as four lumps.

[0093] After the raw material residue oil passes through the delayed coking unit, some major gas products will be generated, including propylene (I), ethylene (J), butadiene (K) and butane (L), each of which is a lumped product. The remaining gas products are divided into two lumped products: dry gas (M) and liquefied gas (N).

[0094] Finally, the raw residue oil passes through the delayed coking unit to produce coke (O), which is the last lump sum.

[0095] Therefore, a fifteen-episode kinetic model was established, with a total of 76 reaction pathways, as follows: Figure 2 shown.

[0096] For each reaction path, there is a K i , corresponding to the existence of an E i and an A i , E i is the activation energy, A i is the pre-factor, K i is the rate constant.

[0097] According to the Arrhenius equation:

[0098] k=Ae -Ea / RT

[0099] Therefore, it is necessary to fit the E of each reaction path i and A i .

[0100] Specifically, machine learning methods may be used, including but not limited to random forest, decision tree, neural network, support vector machine, KNN, etc.

[0101] In order to obtain data for machine learning, a series of standardized experiments are needed. Through standardized experiments, the amount of coke produced under different four-component conditions and different reaction temperatures, as well as the yields of gasoline, diesel, dry gas, and liquefied gas can be obtained. Then, through the above-mentioned machine learning method, the E of each reaction path can be fitted. i and A i .

[0102] Get E i and A i Finally, the coking tower can be modeled through the grid modeling tool. The judgment of the amount of coke generated is based on the following two aspects: first, the stress analysis of the tar adhering to the wall is carried out; second, the part that is not adhered to the wall but coked will grow with the coking in the longitudinal direction of the coking tower. This requires calculating the k of each reaction path through the actual operating conditions, and then calculating the new coke generation at the current moment.

[0103] In the embodiments of the present invention, the coke drum is generally longitudinal, unlike the microwave reactor which is transverse. The coking process is actually a process of continuous coking from the bottom to the top of the drum. Therefore, it cannot be simply judged by the force analysis method used in microwave reactors. Instead, it is necessary to consider the influence of the lumped reaction on the coking rate and the longitudinal coking rate based on the above-mentioned lumped kinetic model. Specifically:

[0104] In the embodiment of the present invention, the coking method is calculated using a gridding modeling tool. Therefore, the concept of "virtual bed" can be introduced. Specifically, there is no real bed in the coke drum. Therefore, in the embodiment of the present invention, the coke drum is logically divided into N virtual beds using a gridding tool. The height of each virtual bed is M. Thus, assuming the actual height of the coke drum is H, then based on experience, the position H' is defined as the critical line of the coke drum (i.e., the designed coking height). When the coking position reaches this height, the coke drum needs to be switched. Therefore, H' is less than H, and H'=M*N.

[0105] Therefore, for a certain moment, the way to calculate the coke production is to obtain the temperature in the virtual bed grid and combine it with the k of each reaction path of the lumped kinetic model to obtain the coke production of the virtual bed.

[0106] Assume that t = 0s is the moment when the raw residue oil enters the coke drum. At this moment, we need to calculate the coke production rate for the coke production at that moment. It is important to note that for this coke production rate, due to the possibility of wall coking, the actual coke production in the virtual bed must be reduced by the coke adhering to the wall, which does not belong to the bed space. This allows us to determine the time it will take for the first virtual bed to be filled with coke at the current coke production rate. Therefore, we can set a time step s and continuously adjust the time it takes for the first virtual bed to be filled with coke through the calculation of each time step.

[0107] When the first virtual bed is filled with coke, we use the same method to calculate when the second virtual bed is filled with coke, until the penultimate virtual bed is filled with coke; when the last virtual bed begins to form coke, the coke tower can be switched.

[0108] In addition, in order to ensure the accuracy of the coking calculation in the coke tower, in the standardized experiment described above, a standard coke physicochemical database can be established for the physical properties of coke, such as density, porosity, and chemical composition indicators such as fixed carbon, volatile matter, ash, and sulfur content. The role of this database is to establish a connection between the coke physicochemical database and the four components of residual oil. This connection can also be established through machine learning methods. In this way, when the calculation results of the coke properties in the actual production process are similar to the results predicted using the actual physicochemical database, it can be considered that coking exists, which can be introduced as a correction parameter into the calculation of the coking situation of the virtual bed.

[0109] In summary, in the embodiments of the present invention, a precise coking prediction method was first established. Specifically, by introducing a lumped kinetic model, the physical significance of the adhesion phenomenon between free coke and the wall during the coking process was mathematically quantified. By calculating the changes in the multiphase flow within the coke drum, the reaction kinetics and force analysis related to the free coke during the coking process were further clarified. Thus, by obtaining the theoretical coking amount based on the reaction kinetics, and through force analysis of the adhesion of free coke to the wall, the drag force between the gas, liquid, and solid phases, gravity, and wall shear stress, combined with fluid flow purging, coking data within the coke drum can be quickly and accurately obtained.

[0110] As can be seen from the above, in the embodiment of the present invention, a three-dimensional thermodynamic model is generated according to each coke tower, and the volume fraction prediction value of the gas-liquid-solid three-phase components and the temperature distribution prediction value are predicted; further, the coke inventory in the coke tower after the preset time is accurately predicted. In this way, the coke tower can be switched in time while fully utilizing the pyrolysis space of the coke tower, thereby effectively improving the processing efficiency of the device and reducing the redundant waste of the coke tower processing capacity.

[0111] In addition, since the embodiment of the present invention can maximize the use of the pyrolysis space of the coke drum, the coke generation time of the coke drum is extended, thereby reducing the number of switching times of the coke drum and saving labor costs.

[0112] Example 2

[0113] Corresponding to the method embodiment, another aspect of the present invention provides a coke drum switching control device in a delayed coking process. Figure 3 The structure diagram of the coke drum switching control device in the delayed coking process provided by the embodiment of the present invention is shown. The coke drum switching control device in the delayed coking process is Figure 1 The device corresponding to the delayed coking coke drum switching control method described in the corresponding embodiment is realized by a virtual device Figure 1 In the corresponding embodiment of the delayed coking coke drum switching control method, each virtual module constituting the delayed coking coke drum switching control device can be executed by an electronic device, such as a network device, a terminal device, or a server. Specifically, the delayed coking coke drum switching control device in the embodiment of the present invention includes:

[0114] Model presetting unit 01 is used to generate and mesh a three-dimensional thermodynamic model of each coke drum in a coking state based on the reactor wall, residual oil feed inlet and light component outlet of the coke drum;

[0115] Parameter determination unit 02 is used to obtain preset operating parameters of a coke drum in real time when the coke drum is in the coking process as input parameters of the three-dimensional thermodynamic model; the input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure, and multiphase flow interphase drag;

[0116] The simulation calculation unit 03 is used to calculate the simulation results of the three-dimensional thermodynamic model according to the input parameters with a preset time step as the calculation cycle; the results include the volume fraction distribution prediction value of the gas-liquid-solid three-phase after one time step, and the temperature distribution prediction value;

[0117] The target grid determination unit 04 is configured to determine a grid whose volume fraction distribution prediction value of the solid phase main component is greater than a preset fraction threshold as a target grid; and calculate the free coke adhesion force of the target grid area, as well as the gravity and shear stress of the solid phase main component in the target grid area.

[0118] a coking grid judging unit 05, configured to judge whether the angle between the resultant force direction of the components of the target grid in the reactor radial direction and the direction of the normal line of the wall section and the reactor radial direction is greater than 90° based on the free coke adhesion, gravity, and shear stress; if so, determine the target grid as a coking grid;

[0119] The coke adhesion prediction unit 06 is used to respectively calculate the coke increment of each coking grid after one time step, and calculate the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid;

[0120] The purge amount calculation unit 07 is used to calculate the gas-solid phase drag, liquid-solid phase drag, gas-liquid phase drag and convection diffusion of each coking grid after one time step, and record their sum as the flow purge amount after one time step;

[0121] The coke inventory prediction unit 08 is used to calculate the predicted coke inventory of the coking grid after one time step by using the difference between the predicted coke adhesion amount and the flow purge amount;

[0122] The control instruction generating unit 09 is used to determine whether the coke drum exceeds the coking critical value according to the predicted coke inventory. If so, the feed valve between the coke drums is switched and the current state of the coke drum is set to decoking.

[0123] It should be noted that the specific implementation and technical effects of the coke drum switching control device in the delayed coking embodiment of the present invention can be referred to Figure 1 The corresponding coke tower switching control method in delayed coking will not be described here in detail.

[0124] Example 3

[0125] Corresponding to the method embodiments, embodiments of the present invention also provide a coke drum switching control device in a delayed coking process, such as a terminal, a server, or the like. The server may be an independent physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms. The terminal may be, but is not limited to, a smartphone, tablet computer, laptop computer, or desktop computer.

[0126] An example diagram of the hardware structure block diagram of the coke drum switching control device in the delayed coking embodiment of the present application is shown in FIG. Figure 4 As shown, this may include:

[0127] Processor 1, communication interface 2, memory 3 and communication bus 4;

[0128] The processor 1, the communication interface 2, and the memory 3 communicate with each other via the communication bus 4;

[0129] Optionally, the communication interface 2 may be an interface of a communication module, such as an interface of a GSM module;

[0130] The processor 1 may be a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application.

[0131] The memory 3 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0132] The processor 1 is specifically configured to execute the computer program stored in the memory 3 to perform the following steps:

[0133] S11, pre-generating a three-dimensional thermodynamic model of each coke drum in a coking state based on the reactor wall, the residual oil feed inlet, and the light component outlet of the coke drum, and performing meshing;

[0134] S12. When a coke drum is in the process of generating coke, obtaining preset operating parameters of the coke drum in real time as input parameters of the three-dimensional thermodynamic model; the input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure, and multiphase flow interphase drag;

[0135] S13, using a preset time step as a calculation cycle, and calculating the simulation results of the three-dimensional thermodynamic model according to the input parameters; the results include a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution;

[0136] S14, determining a grid whose volume fraction distribution predicted value of the solid phase main component is greater than a preset fraction threshold as a target grid; and calculating the free coke adhesion force of the target grid area, as well as the gravity and shear stress of the solid phase main component in the target grid area;

[0137] S15, judging whether the angle between the resultant force direction of the components of the target grid in the radial direction of the reactor and the direction of the normal line of the wall section and the radial direction of the reactor is greater than 90° based on the free coke adhesion, gravity and shear stress; if so, determining the target grid as a coking grid;

[0138] S16, respectively calculating the coke increment of each coking grid after one time step, and calculating the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid;

[0139] S17, respectively calculating the gas-solid phase drag, liquid-solid phase drag, gas-liquid phase drag and convection diffusion of each coking grid after one time step, and recording their sum as the flow purge amount after one time step;

[0140] S18, calculating the difference between the predicted amount of coke adhesion and the flow purge amount to obtain the predicted coke inventory of the coking grid after one time step;

[0141] S19. Determine whether the coke drum exceeds the critical value of coking based on the predicted coke inventory. If so, switch the feed valves between the coke drums and set the current state of the coke drum to decoking.

[0142] The above-mentioned product can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not fully described in this embodiment, please refer to the coke drum switching control method in the delayed coking provided by the embodiment of the present invention.

[0143] Example 4

[0144] In an embodiment of the present invention, a storage medium is further provided. The storage medium may store a program suitable for execution by a processor, wherein the program is used to:

[0145] S11, pre-generating a three-dimensional thermodynamic model of each coke drum in a coking state based on the reactor wall, the residual oil feed inlet, and the light component outlet of the coke drum, and performing meshing;

[0146] S12. When a coke drum is in the process of generating coke, obtaining preset operating parameters of the coke drum in real time as input parameters of the three-dimensional thermodynamic model; the input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure, and multiphase flow interphase drag;

[0147] S13, using a preset time step as a calculation cycle, and calculating the simulation results of the three-dimensional thermodynamic model according to the input parameters; the results include a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution;

[0148] S14, determining a grid whose volume fraction distribution predicted value of the solid phase main component is greater than a preset fraction threshold as a target grid; and calculating the free coke adhesion force of the target grid area, as well as the gravity and shear stress of the solid phase main component in the target grid area;

[0149] S15, judging whether the angle between the resultant force direction of the components of the target grid in the radial direction of the reactor and the direction of the normal line of the wall section and the radial direction of the reactor is greater than 90° based on the free coke adhesion, gravity and shear stress; if so, determining the target grid as a coking grid;

[0150] S16, respectively calculating the coke increment of each coking grid after one time step, and calculating the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid;

[0151] S17, respectively calculating the gas-solid phase drag, liquid-solid phase drag, gas-liquid phase drag and convection diffusion of each coking grid after one time step, and recording their sum as the flow purge amount after one time step;

[0152] S18, calculating the difference between the predicted amount of coke adhesion and the flow purge amount to obtain the predicted coke inventory of the coking grid after one time step;

[0153] S19. Determine whether the coke drum exceeds the critical value of coking based on the predicted coke inventory. If so, switch the feed valves between the coke drums and set the current state of the coke drum to decoking.

[0154] Optionally, the detailed functions and extended functions of the program may refer to the above description.

[0155] The above-mentioned product can execute the method provided by the embodiment of the present invention, and has the functional modules and beneficial effects corresponding to the execution method. For technical details not fully described in this embodiment, please refer to the methods provided by other embodiments of the present invention.

[0156] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0157] In the several embodiments provided herein, it should be understood that the disclosed systems, devices, and methods may be implemented in other ways. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0158] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0159] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0160] It should be understood that in the embodiments of the present application, the various embodiments and features can be combined with each other to solve the aforementioned technical problems.

[0161] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0162] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present application. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coke drum switching control method in delayed coking, characterized in that: Including steps: S11, pre-generating a three-dimensional thermodynamic model of each coke drum in a coking state based on the reactor wall, the residual oil feed inlet, and the light component outlet of the coke drum, and performing meshing; S12. For a target coke drum in a coking state, obtaining preset operating parameters of the target coke drum in real time as input parameters of a corresponding three-dimensional thermodynamic model; The input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure and multiphase flow interphase drag; S13, using a preset time step as a calculation cycle, and calculating the simulation results of the three-dimensional thermodynamic model according to the input parameters; the results include a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution; S14, determining a grid whose volume fraction distribution predicted value of the solid phase main component is greater than a preset fraction threshold as a target grid; and calculating the free coke adhesion force of the target grid area, as well as the gravity and shear stress of the solid phase main component in the target grid area; S15, judging whether the angle between the resultant force direction of the components of the target grid in the radial direction of the reactor and the direction of the normal line of the wall section and the radial direction of the reactor is greater than 90° based on the free coke adhesion, gravity and shear stress; if so, determining the target grid as a coking grid; S16, respectively calculating the coke increment of each coking grid after one time step, and calculating the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid; S17, respectively calculating the gas-solid phase drag, liquid-solid phase drag, gas-liquid phase drag and convection diffusion of each coking grid after one time step, and recording their sum as the flow purge amount after one time step; S18, calculating the difference between the predicted amount of coke adhesion and the flow purge amount to obtain the predicted coke inventory of the coking grid after one time step; S19. Determine whether the target coke drum exceeds the coking critical value based on the predicted coke inventory. If so, switch the coke drum and set the current state of the target coke drum to decoking.

2. The method for controlling the switching of coke drums in delayed coking according to claim 1, wherein: The gridding methods include: One or more of tetrahedral mesh, hexahedral mesh, pyramid mesh, wedge mesh and polyhedral mesh are used.

3. The method for controlling the switching of coke drums in delayed coking according to claim 2, wherein: The gridded calibration method includes: One or more of general physics, fluid dynamics, plasmas, and semiconductors.

4. The method for controlling the switching of coke drums in delayed coking according to claim 3, wherein: The generating of a three-dimensional thermodynamic model of each coke drum when coking and performing meshing includes: Assume that the cavity volume of the three-dimensional thermodynamic model of the coke drum is V and the height is H; the three-dimensional thermodynamic model after gridding has α grid units and is stored in the set Data_α, where the temperature of the i-th grid unit belonging to the set Data_α is T i , the amount of coke is Coke i .

5. The coke drum switching control method in delayed coking according to claim 4, characterized in that: The calculation formula of the gas-solid phase drag force includes: An energy minimum multiscale model is used, and the equations of the energy minimum multiscale model include: Among them, F gs is the drag force between gas and solid phases, Re is the Reynolds coefficient, ε is the average void ratio, d p is the particle diameter, ρ is the average density, u g is the gas superficial velocity, u p is the particle superficial velocity.

6. The coke drum switching control method in delayed coking according to claim 5, characterized in that: The calculation formula of the drag force between liquid and solid phases includes: The Schiller-Naumann uniform drag model is used. The equations of the Schiller-Naumann uniform drag model include: Among them, F ls is the drag force between liquid and solid phases, C D,ls is the liquid-solid two-phase drag coefficient, and u is the fluid superficial velocity.

7. The coke drum switching control method in delayed coking according to claim 6, characterized in that: The calculation formula of the drag force between the gas and liquid phases includes: The Grace drag model is used, and the equations of the Grace drag model include: Among them, F gl is the drag force between gas and liquid phases, C D,gl is the drag coefficient of the gas-liquid two-phase, g is the acceleration due to gravity, d b is the bubble diameter, ρ l is the liquid density, ρ g is the gas phase density, u T is the terminal velocity.

8. The coke drum switching control method in delayed coking according to claim 7, characterized in that: The coking critical value includes: The total content of all solid phases in the coke drum shall not exceed the theoretical coking rate of the slag-minus raw materials, and the height of the coking zone shall not exceed the designed coking height of the coke drum.

9. The coke drum switching control method in delayed coking according to claim 8, characterized in that: The calculation process of coking mode using a gridded 3D thermodynamic model includes: Assume that the actual height of the coke drum is H and the designed coke height is H'; based on H', the coke drum is logically divided into N virtual beds using a gridding tool, and the height of each virtual bed is M; H' = M*N; Starting with the bottom virtual bed, the coke production of each virtual bed is calculated sequentially from bottom to top, including: when the current virtual bed is full of coke, the coke production of the virtual bed above it is calculated; when the last virtual bed begins to produce coke, it is determined that the height of the coke production area has reached the designed coke production height.

10. A coke drum switching control device in delayed coking, characterized in that: include: A model presetting unit is used to pre-generate a three-dimensional thermodynamic model of each coke drum in a coking state according to the reactor wall, residual oil feed inlet and light component outlet of the coke drum and perform meshing; A parameter determination unit is used to obtain, in real time, preset operating parameters of a target coke drum in a coking state as input parameters of a corresponding three-dimensional thermodynamic model; The input parameters include: residual oil feed rate, initial feed temperature, lumped kinetic model, residual oil feed properties, wall heat flux, wall roughness height, solid phase wall shear stress, outlet pressure and multiphase flow interphase drag; a simulation calculation unit, configured to calculate a simulation result of the three-dimensional thermodynamic model based on the input parameters with a preset time step as a calculation period; the result including a predicted value of the volume fraction distribution of the gas-liquid-solid three phases after one time step, and a predicted value of the temperature distribution; a target grid determination unit, configured to determine a grid having a volume fraction distribution prediction value of a solid phase main component greater than a preset fraction threshold as a target grid; and respectively calculate the free coke adhesion force of the target grid area, and the gravity and shear stress of the solid phase main component in the target grid area; a coking grid judging unit, configured to judge, based on the free coke adhesion, gravity, and shear stress, whether the angle between the resultant force direction of the target grid components in the reactor radial direction and the direction of the normal line of the wall section and the reactor radial direction is greater than 90°; if so, determining the target grid as a coking grid; a coke adhesion prediction unit, configured to respectively calculate the coke increment of each coking grid after one time step, and calculate the predicted amount of coke adhesion after one time step based on the current coke inventory of the coking grid; a purge volume calculation unit for respectively calculating the gas-solid phase drag, the liquid-solid phase drag, the gas-liquid phase drag, and the convection diffusion of each of the coking grids after one time step, and recording their sum as the flow purge volume after one time step; A coke inventory prediction unit, configured to calculate the predicted coke inventory of the coking grid after one time step by using the difference between the predicted coke adhesion amount and the flow purge amount; A control instruction generating unit is used to determine whether the target coke drum exceeds the coking critical value based on the predicted coke inventory. If so, the coke drum is switched and the current state of the target coke drum is set to decoking.

11. A coke drum switching control device in delayed coking, characterized in that: include: memory for storing computer programs; A processor is used to call and execute the computer program to implement the steps of the coke drum switching control method in delayed coking as described in any one of claims 1 to 9.

12. A storage medium, characterized in that: The invention comprises a software program, wherein the software program is suitable for a processor to execute the steps of the coke drum switching control method in delayed coking as claimed in any one of claims 1 to 9.

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