Parameter value correction method for chemical process simulation program

Abstract

The application belongs to the technical field of chemical process simulation, and discloses a parameter value correction method of a chemical process simulation program.The parameter value correction method of the chemical process simulation program comprises the following steps: iteratively calculating according to initial values of a plurality of parameters input in the simulation program; judging whether the result of the iterative calculation converges; if the result of the iterative calculation does not converge, determining a to-be-corrected parameter and a correction value of the to-be-corrected parameter from the plurality of parameters; replacing the initial value of at least one to-be-corrected parameter with the corresponding correction value, and iteratively calculating again to judge whether the result of the iterative calculation converges.The application simplifies the processing steps of the non-convergence phenomenon in the chemical process simulation program, enables the chemical process simulation program to have a certain parameter correction function, and has a certain positive effect on reducing the work difficulty of technical personnel and improving the design efficiency of the simulation program.

Description

Technical Field

[0001] This invention belongs to the field of chemical process simulation technology, specifically, it relates to a method for correcting parameter values ​​in a chemical process simulation program. Background Technology

[0002] The ethylene industry is a crucial part of the petrochemical sector, accounting for over 75% of global petrochemical production. Ethylene output is widely regarded as a key indicator of a country's petrochemical industry development, highlighting its vital role in the national economy. In recent years, global demand for ethylene has been robust, leading to a year-on-year increase in the utilization rate of its production facilities. Among conventional ethylene production projects, naphtha cracking to ethylene production is the most prevalent process. Therefore, optimizing the chemical process simulation of naphtha cracking to ethylene production to reduce failure rates and improve production efficiency is particularly important.

[0003] Chemical process simulation is a major component of process design. Process simulation programs are used to mathematically model and solve processes and equipment.

[0004] For the ethylene industry, the application of chemical process simulation technology can save significant amounts of money, time, and manpower previously consumed in experimentally exploring optimal process conditions. It allows us to understand, analyze, and predict deep-seated problems in production from a holistic system perspective, enabling equipment optimization, process analysis, and process integration. This ultimately achieves the goals of optimized production, resource conservation, environmental friendliness, and improved economic efficiency. In today's context of energy scarcity, natural resource shortages, and fierce market competition, the development and application of this technology are receiving increasing attention.

[0005] By inputting a complete set of initial parameter values ​​into each unit module in the process, if suitable initial values ​​can be provided, the iterative calculation time of the chemical process simulation program can be reduced and the complexity of its calculation operation can be decreased, thereby improving the running efficiency of the simulation program.

[0006] In practice, chemical process simulation programs often use different colors to fill in the icons of equipment units to indicate whether their initial values ​​have been fully entered. After the initial values ​​are entered, the model is solved through iterative calculations. In the cracked gas separation process, there are a large number of circulating streams. Since the parameters of the circulating streams are unknown and cannot be estimated before the results of the upstream equipment units are calculated, it is not possible to directly calculate each equipment unit sequentially according to the process topology. To handle the situation where there are circulating stream loops in the process, it is necessary to apply the breaking and convergence techniques. The breaking technique can open the loops by setting a convergence unit and its corresponding assumed process parameters at the break point, allowing each unit in the process to be solved sequentially.

[0007] The convergence verification technique involves solving the problem sequentially according to the initial values ​​to obtain the calculated values ​​at the convergence units. The assumed values ​​are then compared with the calculated values. If the difference is not within the tolerance range (the calculation results do not converge), the correction parameter values ​​are adjusted and the above iterative calculation is repeated until the difference between the correction value and the calculated value is within the tolerance range (the calculation results converge).

[0008] The initial parameter values ​​need to be adjusted when the process fails to converge or when there are devices that issue warnings. The objects requiring adjustment include setting appropriate initial parameter values ​​at the break-through unit (equipment parameter initial values) and also the initial values ​​of material parameters within the equipment unit (process parameter initial values).

[0009] The parameter adjustment process typically relies on experienced designers. Based on the results and information from iterative calculations, they analyze and reason about the reasons for equipment and process non-convergence, then modify the initial values ​​of the process parameters, repeating the calculations until the process converges. This requires designers to have considerable experience, a deep understanding of the target process, and the ability to adjust the process while considering different parameter modification points and initial value modification magnitudes. This process places high demands on the comprehensive abilities of the designers. Furthermore, the inefficient method of repeatedly modifying and calculating to troubleshoot problems is extremely low, and it cannot simultaneously obtain enough other convergent solutions. This results in time-consuming and labor-intensive chemical simulation programs with unreliable output quality.

[0010] The separation process for ethylene production from naphtha cracking involves numerous pieces of equipment and streams. During the process simulation design, a significant amount of initial value information relies on manual adjustments by the designers. Although designers can set a set of initial values ​​similar to previous processes based on existing process templates, the detailed adjustments to these initial values ​​remain time-consuming and inefficient when the naphtha composition, feed rate, and target output vary across plants, leading to changes in design objectives. This makes it difficult to determine suitable initial values.

[0011] In process simulation calculations, multiple devices and streams may simultaneously fail to converge. Due to the highly coupled nature of the naphtha cracking to ethylene separation process, achieving convergence requires multiple adjustments to the initial values ​​of each device, either individually or collaboratively. However, designers often struggle to simultaneously accommodate all adjustment methods, typically resorting to manual, sequential adjustments, which are time-consuming.

[0012] In summary, due to the characteristics of computer technology, all intermediate variable information in the computation resides in memory or temporary files. If the simulation process fails to converge as expected, the non-convergence will be reflected in the process information of each unit and stream. Appropriate analysis and reasoning can provide valuable reference for further adjustments to the initial values. However, currently, this process is generally adjusted manually by engineers, which is limited by the experience of the designers. Furthermore, different initial value settings and their corresponding results provide rich and useful information for further initial value adjustments. Parallel operation can undoubtedly improve the efficiency of iterative calculations after setting different initial values, providing more comprehensive information. Comprehensive analysis of the information from parallel computation is beneficial for convergence and improves efficiency.

[0013] In view of this, the present invention is hereby proposed. Summary of the Invention

[0014] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for correcting parameter values ​​in a chemical process simulation program, so as to reduce the difficulty of operation for technicians and improve the design efficiency and operation efficiency of the simulation program.

[0015] To solve the above-mentioned technical problems, the basic concept of the technical solution adopted by the present invention is as follows:

[0016] A method for correcting parameter values ​​in a chemical process simulation program is provided, including:

[0017] Iterative calculations are performed based on the initial values ​​of several parameters input into the simulation program;

[0018] Determine whether the results of the iterative calculation have converged;

[0019] If the result of the iterative calculation does not converge, then determine the parameter to be corrected and the correction value of the parameter to be corrected from the aforementioned parameters.

[0020] Replace the initial value of at least one parameter to be corrected with the corresponding correction value, perform iterative calculation again, and determine whether the result of the iterative calculation converges.

[0021] Furthermore, the parameters include equipment parameters of the equipment required to complete the chemical process;

[0022] The results of the iterative calculation include the operating results of each device corresponding to the parameters, as well as the operating results of the chemical process; the devices whose operating results do not converge are the devices that do not converge in the simulation program.

[0023] If the result of the iterative calculation does not converge, the non-convergent device and its device information are determined based on the result of the iterative calculation.

[0024] Based on the results of the iterative calculation and the equipment information of the non-converging equipment, determine the equipment parameters to be corrected and the correction values ​​of the equipment parameters to be corrected.

[0025] Preferably, the device information of the non-convergent device includes: the device type of the non-convergent device.

[0026] Furthermore, the simulation program includes pre-set standard operating databases for various equipment parameter conditions.

[0027] Based on the device information of the non-converging device, the initial parameter values ​​are determined through a standard operating database to iteratively calculate the reasons for the non-convergence.

[0028] The reasons for non-convergence include that the equipment parameters do not conform to the design specifications;

[0029] Preferably, based on the reasons for non-convergence, the equipment parameters to be corrected and the correction values ​​of the equipment parameters to be corrected are determined;

[0030] Preferably, determining the device parameter to be corrected and the correction value of the device parameter to be corrected includes determining the correction value of the device parameter according to a preset standard;

[0031] Preferably, if the device parameters are detected to be inconsistent with the preset standard, the parameter correction value is determined according to the preset standard.

[0032] Furthermore, the failure of the device parameters to meet the preset standards includes: unreasonable application of the device and / or abnormal device function;

[0033] If it is detected that not all device functions are enabled, it is determined that the device application is unreasonable;

[0034] If undetectable flow information is detected in the device, it is determined that the device is malfunctioning.

[0035] Furthermore, the corrected values ​​of the equipment parameters are iteratively calculated again to determine whether the results of the iterative calculation converge.

[0036] If the calculation results of the device parameter correction value are found to be converged, then the corresponding correction value of the device parameter will be determined as the final device parameter value.

[0037] Furthermore, the parameters also include process parameters of the chemical process;

[0038] The results of the iterative calculations include the operating results of each device corresponding to the parameters, as well as the operating results of the chemical process.

[0039] If the results of the iterative calculation do not converge, the process parameters to be corrected and their correction values ​​are determined based on the results of the iterative calculation.

[0040] Furthermore, the simulation program has a preset standard for determining the correction coefficients of the process parameters, and the correction coefficients of the process parameters are determined according to the standard for determining the correction coefficients of the process parameters.

[0041] Based on the results of iterative calculations, the correction values ​​of the process parameters to be corrected are determined using the correction coefficients of the process parameters.

[0042] Preferably, the reasons for non-convergence include adjustments or changes to the initial values ​​of process parameters;

[0043] Preferably, when the initial value of the process parameter is adjusted or changed, the correction value is determined according to the correction coefficient of the process parameter;

[0044] Preferably, determining the correction coefficient of the process parameter according to the correction coefficient determination standard includes: determining the corresponding correction coefficient based on the change range of the adjusted process parameter compared to the initial process parameter, and then determining the correction value of the process parameter to be corrected;

[0045] Preferably, determining the correction value of the process parameter to be corrected based on the magnitude of the change in the adjusted process parameter compared to the initial process parameter includes: adding the change corresponding to the correction coefficient to the initial process parameter value to determine the correction value of the process parameter to be corrected, or subtracting the change corresponding to the correction coefficient from the initial process parameter value to determine the correction value of the process parameter to be corrected.

[0046] Further, the step of replacing the initial value of at least one parameter to be corrected with the corresponding correction value and performing iterative calculation again includes:

[0047] Upon receiving a signal that the parameter value correction is complete, at least one parameter correction value will be iteratively calculated in the program.

[0048] Check whether the correction value of the detection parameter exhibits non-convergence in the calculation;

[0049] If one or more parameter correction values ​​are found to converge in the iterative calculation, then one or more process parameter correction values ​​are determined as the final process parameter values.

[0050] Furthermore, the one or more process parameter correction values ​​are combined to form different schemes, and multiple different schemes are input into the chemical process simulation program in parallel and synchronously for iterative calculation to detect whether each scheme converges;

[0051] Preferably, the simulation program is set to a maximum / minimum number of parameters that can be modified simultaneously, N1, to avoid having too many schemes and thus reduce memory consumption;

[0052] Preferably, N1 ∈ [2, 10).

[0053] Furthermore, methods for determining the maximum / minimum number of parameters N1 that can be modified simultaneously include:

[0054] If all combinations of corrected parameter values ​​are found to converge after iterative calculation, a rationality evaluation is performed, and the converged combinations are further screened and determined.

[0055] Preferably, the rationality assessment includes: the number of abnormal prompting devices in the chemical process simulation program and / or the number of abnormal prompts for each device and / or the magnitude of parameter correction changes;

[0056] Preferably, if multiple combinations of modified initial values ​​converge simultaneously, the combination with fewer abnormal prompts in the chemical process simulation program and / or fewer abnormal prompts for each device and / or smaller parameter modification ranges is selected as the final parameter values ​​for the final chemical process, thus determining the final designed process.

[0057] By adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0058] 1. The operation steps of the chemical process simulation program are simplified. Through reasonable analysis and judgment of the existing data, the parameters that do not converge and the correction target values ​​of the non-convergent parameters are determined. The determined parameter correction values ​​are then recalculated, and the convergence of the calculation results is checked. This solution enables the chemical process simulation program to have a certain self-parameter correction capability, which has a positive effect on reducing the work difficulty of technicians, improving the design efficiency of the simulation program, and improving the overall operating efficiency of the simulation program.

[0059] 2. By comparing single or limited data, the simulation program can more efficiently identify the equipment to be corrected and its correction value, thereby improving the operating efficiency of the simulation program and reducing the workload and intensity of technicians.

[0060] 3. The difficulty of the initial value adjustment process has been reduced, and the efficiency of the separation process design for naphtha cracking to ethylene has been improved by converting serial operations into parallel operations.

[0061] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0062] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0063] Figure 1 This is a flowchart of the judgment logic of the chemical process simulation program of the present invention;

[0064] Figure 2 This is the overall judgment logic flowchart of the chemical process simulation program of this invention.

[0065] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0067] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0068] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0069] like Figures 1 to 2 As shown, this invention provides a method for correcting parameter values ​​in a chemical process simulation program by designing a correction control for non-convergence phenomena in the program. Detailed implementation method:

[0071] See appendix Figure 1 and attached Figure 2 The parameter value correction method for a chemical process simulation program described in this embodiment includes:

[0072] Iterative calculations are performed based on the initial values ​​of several parameters input into the simulation program;

[0073] Determine whether the results of the iterative calculation have converged;

[0074] If the result of the iterative calculation does not converge, then determine the parameter to be corrected and the correction value of the parameter to be corrected from the aforementioned parameters.

[0075] Replace the initial value of at least one parameter to be corrected with the corresponding correction value, perform iterative calculation again, and determine whether the result of the iterative calculation converges.

[0076] The above scheme simplifies the operation steps of the chemical process simulation program. By reasonably analyzing and judging the existing data, the non-convergent parameters and their correction target values ​​are determined. The determined parameter correction values ​​are then recalculated, and the convergence of the calculation results is checked. This scheme enables the chemical process simulation program to have a certain self-parameter correction capability, allowing for the faster design of corresponding convergent chemical process simulation programs. It also plays a positive role in reducing the operational difficulty for technicians and improving the simulation efficiency of the program.

[0077] Specifically, the initial values ​​of several parameters initially input into the simulation program are a complete set of initial parameter values ​​that can be used for calculation, determined based on previous design and experimental experience.

[0078] It should be noted that iteration is an activity involving repeated feedback processes, typically aimed at approximating a desired goal or result. Each repetition of a specific process is called an "iteration," and the result of each iteration serves as the initial value for the next. It involves repeatedly executing a series of computational steps, deriving subsequent quantities from preceding ones. Each result in this process is obtained by applying the same computational steps to the result of the previous iteration.

[0079] The iterative calculation in the chemical process simulation program of this application refers to: according to relevant equipment specifications and industry regulations, calculating a specific combination of initial parameter values ​​by repeatedly outputting and inputting data into a specific program, thereby determining the error within a certain calibration range. When the rate of non-convergence in the output results of multiple iterative calculations exceeds a certain preset standard, it is determined that the program has a non-convergence problem. Subsequently, the cause of non-convergence is determined based on the output results of the iterative calculations and the equipment information of the identified non-converging equipment.

[0080] Furthermore, the parameters include equipment parameters of the equipment required to complete the chemical process.

[0081] The results of the iterative calculation include the operating results of each device corresponding to the parameters, as well as the operating results of the chemical process; the devices whose operating results do not converge are the devices that do not converge in the simulation program.

[0082] If the result of the iterative calculation does not converge, the non-convergent device and its device information are determined based on the result of the iterative calculation.

[0083] Based on the results of the iterative calculation and the device information of the non-converging device, the device parameters to be corrected and the correction values ​​of the device parameters to be corrected are determined.

[0084] Preferably, the device information of the non-convergent device includes: the device type of the non-convergent device.

[0085] The types of non-converging devices described above allow users to intuitively identify non-converging devices and easily observe the reasons for non-convergence, as well as the correction process and results.

[0086] Using the above scheme, the system identifies equipment exhibiting non-convergence based on calculation results, and determines the relevant equipment information. Based on this information, it then identifies the parameters requiring correction and their correction values. This process requires no human intervention from technicians; the system automatically determines the appropriate adjustment and correction scheme, thus avoiding potential human error and improving the operational efficiency of the chemical process simulation program.

[0087] It is understandable that when the iterative calculation fails to converge, it may be due to problems with the initial equipment parameters of the equipment itself and / or the process parameters of the input materials. Therefore, this embodiment provides a procedure and solution for adjusting and correcting the initial values ​​of the simulation parameters (equipment parameters and process parameters) of the chemical process.

[0088] Specifically, what needs to be clarified when performing the corresponding iterative calculations is that the iterative calculation rules are fixed (the iterative program is determined), the maximum number of iterations N is determined, and the standard value range is determined (the basis for judging whether convergence has occurred).

[0089] Specifically, the non-convergence of the iterative calculation result means that: after the process parameters are iteratively calculated in the corresponding equipment (through the program steps of this equipment), if the deviation between the result of the previous iterative calculation and the result of the current iterative calculation is too large and exceeds the set standard, resulting in the non-convergence of the iterative calculation result, then the corresponding equipment is determined to be a non-convergent equipment.

[0090] Preferably, when a non-convergence phenomenon is detected in the result of the current iteration calculation, the calculation is not stopped immediately, but the iteration calculation continues, using the result of the previous iteration calculation as the initial value of the current operation, and so on, until the maximum number of iterations N is run. The convergence of the calculation in this step is determined by the proportion of result deviation (non-convergence phenomenon) in all iteration calculation results.

[0091] More preferably, convergence is determined by the proportion of result deviations (non-convergence) in all iterative calculations to the number of iterations.

[0092] It should be noted that the equipment's failure to converge is reflected in the results of iterative calculations of process parameters, and is also directly reflected in the system prompts from the simulation software.

[0093] Specifically, the system prompts include: equipment information of the non-converging equipment itself and the operating information of process parameters in the non-converging equipment.

[0094] Specifically, the cause of non-convergence is determined based on the equipment information and process parameters of the non-converging device itself, which are read into the equipment.

[0095] Furthermore, the simulation program includes a set of standard operating databases with various equipment parameter conditions.

[0096] Based on the device information of the non-converging device, the initial parameter values ​​are determined through a standard operating database to iteratively calculate the reasons for the non-convergence.

[0097] The reasons for non-convergence include that the equipment parameters do not conform to the design specifications.

[0098] Preferably, based on the reasons for non-convergence, the equipment parameters to be corrected and the correction values ​​of the equipment parameters to be corrected are determined.

[0099] Preferably, determining the device parameter to be corrected and the correction value of the device parameter to be corrected includes determining the correction value of the device parameter according to a preset standard.

[0100] Preferably, if the device parameters are detected to be inconsistent with the preset standard, the parameter correction value is determined according to the preset standard.

[0101] The chemical simulation program has a standard operation database with results of standard operation under various equipment parameter conditions. The actual operation results are compared with the theoretical (converged) operation results in the standard operation database. Parameters that exceed the allowable deviation range are selected and identified as parameters to be corrected. The correction target value of the corresponding parameter to be corrected is determined according to the actual deviation.

[0102] By adopting the above scheme, the simulation program can more efficiently identify the equipment to be corrected and the correction value of the equipment to be corrected by comparing single or limited data, thereby improving the operating efficiency of the simulation program and reducing the workload and intensity of technicians.

[0103] Specifically, the standard operating database contains theoretical operating results of process parameters under calibrated equipment parameters based on experimental experience and equipment requirements specifications.

[0104] The theoretical and actual operating results contained in the standard operating database are often reflected in the differences in one or more types of device parameters. Based on the differences in these parameters, the reasons for non-convergence of non-converging devices can be determined.

[0105] Furthermore, the failure of the device parameters to meet the preset standards includes: unreasonable device application and / or abnormal device function.

[0106] If it is detected that not all device functions are enabled, it is determined that the device application is unreasonable.

[0107] If undetectable flow information is detected in the device, it is determined that the device is malfunctioning.

[0108] By adopting the above scheme, the corresponding equipment problems are identified, which facilitates the determination of the corrected values ​​of the equipment parameters by running the corresponding problem-solving schemes. This simplifies the operation logic of the correction method and improves the efficiency of handling non-convergence phenomena.

[0109] Specifically, the unreasonable application of the equipment mainly stems from abnormal heat loads in certain containers. These abnormal heat loads manifest as the container's functions not being fully utilized, requiring assistance from other auxiliary equipment to achieve the pre-set effects. For example, the container may include a heat exchanger, but in the process, it is only used for gas-liquid separation; consequently, subsequent equipment is needed to function as a heat exchanger to assist in completing this processing step.

[0110] In terms of the application field of this embodiment, it is mainly reflected in the following: in order to meet the requirements of constant flow rate of circulating logistics and no heat exchange process in the tank, the method of adjustment is mainly to modify the total feed amount of refrigerant.

[0111] Specifically, for a container with two feed streams—one circulating stream and one refrigerant stream—the following formula applies:

[0112]

[0113] Q CU It is the refrigerant flow rate after adjustment, Q HC 'a' represents the circulating logistics flow rate, 'a' represents the proportion of gas mass in the circulating logistics, and 'b' represents the proportion of liquid mass in the refrigerant.

[0114] Specifically, the abnormal equipment function is reflected in the abnormal parameters of the equipment. The abnormal parameters include: the presence of gaseous components in the pump inlet stream, the presence of liquid components in the compressor inlet stream, and the occurrence of cross-temperature in the heat exchanger.

[0115] When a pump exhibits an abnormality indicating the presence of gaseous components in its inlet stream and / or a compressor exhibits an abnormality indicating the presence of liquid components in its inlet stream, this abnormality is generally caused by an upstream separator malfunction. The upstream separator divides the fluid into two streams, which exchange heat with other fluids. One of these streams undergoes a phase change during the heat exchange process and, after being mixed by the mixer and returned to the pump or compressor, causes this abnormality.

[0116] Eliminating the above-mentioned abnormalities is mainly achieved by adjusting the initial value of the separation rate of the upstream separator. Taking the presence of a gas phase in the pump as an example: the specific operation is to set the initial value of the flow rate of the stream that undergoes phase change in the separator to the original value minus the amount of gas phase after phase change, as shown in Equation 2:

[0117] Q new =Q old -Q gas (2);

[0118] In the formula Q new Q represents the flow rate of the stream that undergoes phase change after heat exchange, distributed by the modified separator. old Q represents the flow rate before modification. gas This indicates the amount of gas phase that has undergone a phase change.

[0119] The abnormal situation of "temperature crossover in the heat exchanger" requires the following adjustment process for the initial values ​​of the process parameters: In this case, the strategy will fix the outlet temperature T1 of one of the streams based on process requirements, and follow the principle of minimum heat transfer temperature difference (let the minimum heat transfer temperature difference be ΔT). min As an adjustment criterion, the outlet temperature T2 of the other stream to be adjusted is set as follows:

[0120] T2=T1±ΔT min (3);

[0121] The modified inlet and outlet temperature difference ΔT is calculated based on the obtained T2. 2new Then set the corresponding flow rate Q. 2New Its value is shown in Equation 4:

[0122]

[0123] In the formula ΔT 2Old Q represents the inlet and outlet temperature difference of the stream before the modification. 2Old This indicates the flow rate of the stream before the modification.

[0124] Furthermore, the corrected values ​​of the equipment parameters are iteratively calculated again to determine whether the results of the iterative calculation converge.

[0125] If the correction value of the device parameter is detected to converge in the iterative calculation, then the corresponding correction value of the device parameter is determined as the final value of the device parameter.

[0126] By adopting the above scheme, if the correction values ​​of the detected equipment parameters are iteratively calculated again and the results converge, the final equipment parameters are determined, ensuring the normal simulation of the chemical simulation program, improving the self-parameter correction capability of the simulation program, greatly improving the simulation efficiency of the simulation program, and significantly reducing the time to obtain more reliable simulation data.

[0127] Specifically, if the corrected values ​​of the device parameters are detected as not converging during iterative calculation, return to the above steps to re-identify the non-converging device and its information; repeat the process multiple times until the problem of the device parameters causing non-convergence is eliminated.

[0128] More specifically, the simulation program is set with a maximum number of repetitions Y. If the problem of non-converging device parameters is not resolved after Y repetitions, a prompt message is pushed to the technicians. The technicians then manually adjust the parameters and / or judge the rationality of the process based on the prompt message.

[0129] It is understood that, in order to facilitate technicians to manually debug the simulation program based on the aforementioned prompts, the prompts shall at least include the devices that do not converge in each repeated iteration, the reasons for non-convergence, and corresponding debugging suggestions.

[0130] Furthermore, the parameters also include process parameters of the chemical process.

[0131] The results of the iterative calculations include the operating results of each device corresponding to the parameters, as well as the operating results of the chemical process.

[0132] If the results of the iterative calculation do not converge, the process parameters to be corrected and their correction values ​​are determined based on the results of the iterative calculation.

[0133] It should be noted that after determining the cause of non-convergence based on calculations, if both adjustments and corrections based on equipment parameter design specifications and the determination of correction values ​​from the database are required, these two methods are performed in parallel without any order of execution.

[0134] Furthermore, the simulation program has a preset standard for determining the correction coefficients of the process parameters, and the correction coefficients of the process parameters are determined according to the standard for determining the correction coefficients of the process parameters.

[0135] Based on the results of iterative calculations, the correction values ​​of the process parameters to be corrected are determined using the correction coefficients of the process parameters.

[0136] Preferably, the reasons for non-convergence include adjustments or changes to the initial values ​​of process parameters;

[0137] Preferably, when the initial value of the process parameter is adjusted or changed, the correction value is determined according to the correction coefficient of the process parameter;

[0138] Preferably, determining the correction coefficient of the process parameter according to the correction coefficient determination standard includes: determining the corresponding correction coefficient based on the change range of the adjusted process parameter compared to the initial process parameter, and then determining the correction value of the process parameter to be corrected;

[0139] Preferably, determining the correction value of the process parameter to be corrected based on the magnitude of the change in the adjusted process parameter compared to the initial process parameter includes: adding the change corresponding to the correction coefficient to the initial process parameter value to determine the correction value of the process parameter to be corrected, or subtracting the change corresponding to the correction coefficient from the initial process parameter value to determine the correction value of the process parameter to be corrected.

[0140] By adopting the above scheme, the simulation program can more efficiently identify the process parameters to be corrected and their correction values ​​by comparing the actual process parameters with the initial process parameters, thereby improving the running efficiency of the simulation program and reducing the workload and intensity of technical personnel.

[0141] The aforementioned two-way adjustment refers to adjusting the corresponding process parameters upwards or downwards according to the degree of modification. It can be understood that the process parameters after two-way adjustment are two values.

[0142] For example, in the process parameters, the material concentration X and material dosage Z, the initial planned output is A, and the planned output is now adjusted to 1.5A. Therefore, according to the scheme of this embodiment, several schemes can be obtained: 1. Material dosage Z is not adjusted, and the material concentration is adjusted to 1.5X; 2. Material dosage is adjusted to 1.5Z, and material concentration X is not adjusted; 3. Material concentration is adjusted to 1.5X, and material dosage is adjusted to 1.5Z; 4. Material concentration is adjusted to 0.5X, and material dosage is adjusted to 0.5Z. According to experiments, schemes 3 and 4 are actually mostly unreasonable. Correspondingly, it is understandable that there are also two other schemes: 5. Material concentration is adjusted to 1.5X, and material dosage is adjusted to 0.5Z; 6. Material concentration is adjusted to 0.5X, and material dosage is adjusted to 1.5Z.

[0143] Conventional process simulation software often only indicates that the process fails to converge at a certain device or flow path, without providing the specific reason for the non-convergence. This means that when adjusting the initial values ​​of the simulated process parameters, in addition to the initial values ​​that can be determined according to design specifications, some process parameters require searching within a certain range to determine their initial values. Therefore, this embodiment describes determining the correction values ​​according to the process parameter correction standard as follows:

[0144] S1. Determine the process parameters that need to be adjusted or corrected;

[0145] When the throughput of the separation process changes, the equipment that is most likely to fail to converge is the reactor and heat exchanger.

[0146] For hydrogenation reactors in chemical processes, the non-convergence caused by insufficient feed hydrogen can be identified by analyzing the product composition. If the hydrogen content in the reactor product is close to zero (<1e-8), it can be confirmed that the hydrogen feed rate needs to be increased to increase the flow rate of the stream entering the reactor from the upstream separator.

[0147] For heat exchangers, the non-convergence is mainly caused by an excessively large heat exchange temperature difference, which can be addressed by directly reducing the initial value of the target material temperature at the hot end outlet of the heat exchanger or reducing the hot end feed temperature.

[0148] It should be noted that lowering the initial target temperature of the hot-end outlet stream in the heat exchanger, thereby reducing the heat exchange temperature difference, is a direct and effective method. However, this involves adjusting the process flow. If the outlet stream does not exit directly but enters the recirculation, it will affect subsequent processes. In this case, it is advisable to reduce the temperature of the hot-end stream feed by increasing the upstream refrigerant dosage.

[0149] S2. After determining the process parameters that need to be adjusted and corrected, it is necessary to determine the target values ​​for adjusting and correcting the process parameters.

[0150] When a process fails to converge due to changes in throughput or output, the magnitude of the output change is first calculated. If the parameter to be adjusted is an extensive quantity such as flow rate, the target value is calculated based on this magnitude. For intensive quantities such as temperature, design specifications such as minimum heat exchange temperature difference must be considered, while a target value is determined by a fixed magnitude (e.g., a 1-degree Celsius reduction in the target temperature of the stream at the hot end of the heat exchanger). In subsequent calculations, if the equipment still fails to converge after adjusting the initial parameter values, the modification magnitude needs to be increased until the process converges or a situation arises requiring adjustment of the initial values ​​of process parameters for other equipment.

[0151] If the process fails to converge due to changes in other process conditions, the target values ​​of the parameters to be adjusted should be calculated using a fixed range (if the direction of the initial value modification cannot be determined, the target values ​​should be calculated bidirectionally with the same range). In subsequent calculations, if the adjusted equipment still fails to converge after the initial values ​​of the adjusted parameters are calculated, the modification range needs to be increased until the process converges or the initial values ​​of the process parameters of other equipment need to be adjusted.

[0152] For example, taking a naphtha cracking process for producing ethylene with an annual output of 1.6 million tons of ethylene as an example, which is adjusted to an annual output of 1.7 million tons due to changes in demand, the calculated basic modification range is (1.7 million - 1.6 million) / 1.6 million × 100% = 6.25%. After the feed flow rate is changed proportionally, the calculation results show that two devices, namely the hydrogenation reactor and a heat exchanger, do not converge.

[0153] Based on the reactor outlet stream information, it is confirmed that the hydrogen feed needs to be increased. Calculations from the heat exchanger indicate that its heat exchange temperature difference is too high, and its outlet stream recycles back into the process flow. Therefore, it is necessary to increase the upstream cold charge and lower its hot-end feed temperature. The original values ​​for these two variables are 260 kg / hr and 261300 kg / hr, respectively.

[0154] The original values ​​were modified by 0.0625 times. Here, we will explain the scheme where both parameters are increased to 1.0625 times their original values. The target values ​​determined after the adjustment are 276.25 kg / hr and 277631.25 kg / hr. If the two devices fail to converge in subsequent calculations, the modification will be increased to 0.125, and the new target values ​​will be 292.5 kg / hr and 293962.5 kg / hr.

[0155] After determining the parameters to be adjusted and the target value, three combinations can be obtained: modify only the hydrogen feed rate, modify only the flow rate of the upstream separator of the heat exchanger, and modify both the hydrogen feed rate and the flow rate of the upstream separator of the heat exchanger.

[0156] Then, the three combinations were applied in parallel to the original chemical process simulation program, and iterative calculations were performed again to obtain the results. For example, the results show that the scheme that modifies both the hydrogen feed rate and the upstream separator flow rate of the heat exchanger can achieve convergent results.

[0157] Specifically, parallel operation refers to simultaneously inputting the multiple parallel schemes formed above into the chemical process simulation program for iterative calculation, performing iterative calculations on multiple parallel schemes in a synchronized manner, and determining whether each of them has converged.

[0158] It should be noted that the correction value of the parameter to be corrected may not be a specific numerical value, but rather a range of values. For example, in the example above, the second adjustment may not be set at 0.125 of the original parameter, but rather a range may be determined, i.e., the second adjustment may be between 0.0625 and 0.125. By using the method of taking values ​​at intervals, multiple adjustment ranges can be determined, and the parameter can be adjusted accordingly, forming multiple parallel adjustment schemes, which can be simultaneously input into the simulation program for verification.

[0159] A factory sets a production target or a specific production dosage requirement for a particular piece of equipment. The target output is for the entire process. Assuming the equipment parameters meet the design specifications, it is mainly affected by the material feed rate and less affected by the parameters of individual pieces of equipment.

[0160] Specifically, reasons for non-convergence include: the device contains flow information that cannot be correctly identified or cannot be identified.

[0161] Specifically, flow information refers to information about secondary reaction products generated during the processing of chemical materials in equipment.

[0162] Further, the step of replacing the initial value of at least one parameter to be corrected with the corresponding correction value and performing iterative calculation again includes:

[0163] Upon receiving a signal that the parameter value correction is complete, at least one parameter correction value will be iteratively calculated in the program.

[0164] Check whether the correction value of the detection parameter does not converge during the calculation.

[0165] Furthermore, if one or more parameter correction values ​​are detected to converge in the iterative calculation, then one or more process parameter correction values ​​are determined as the final process parameter values.

[0166] By adopting the above scheme, if the correction value of the process parameter is detected and the result of the iterative calculation converges, the final process parameter is determined, ensuring the normal simulation of the chemical simulation program, improving the self-parameter correction capability of the simulation program, greatly improving the simulation efficiency of the simulation program, and significantly reducing the time to obtain more reliable simulation data.

[0167] It should be noted that one or more process parameter correction values ​​are determined from the process parameter correction standard to form different schemes, which are run in parallel in the simulation program; however, the parameters in one or more parallel combined adjustment schemes formed by the corrected equipment parameter correction values ​​must be adjusted in combination (that is, the parameters in each combination formed by this scheme need to be modified).

[0168] Furthermore, the one or more process parameter correction values ​​are combined to form different schemes, and multiple different schemes are input into the chemical process simulation program in parallel and synchronously for iterative calculation to detect whether each scheme converges;

[0169] Preferably, the simulation program is set to a maximum / minimum number of parameters that can be modified simultaneously, N1, to avoid having too many schemes and thus reduce memory consumption;

[0170] Preferably, N1 ∈ [2, 10).

[0171] Understandably, when multiple process parameters are adjusted simultaneously, the resulting combination scheme is quite complex. Although it is possible to achieve convergence for the parameters, it is still unrealistic and places a heavy computational burden on the simulation program. Therefore, limiting the maximum number of parameters that can be adjusted simultaneously, N1, can reduce the running burden of the simulation program. However, when only one process parameter is adjusted, convergence is often not achieved with a few adjustments. Therefore, controlling the minimum number of parameters that can be modified simultaneously, N1, can ensure the running efficiency of the simulation program.

[0172] When adjusting parameters, the initial values ​​of each parameter, determined according to the design rules, must first be adjusted. Then, the initial values ​​are modified. To compare the calculation results after different modifications, the parameters to be modified and the newly determined initial values ​​need to be combined.

[0173] For example: First, determine the maximum number of parameters that can be modified simultaneously to avoid complex adjustment schemes with too many parameter combinations. Then, combine the parameters according to different target initial values ​​of the parameters to be adjusted to obtain the final results. In a non-convergent process with m searched process parameters that need modification, if the maximum number of parameters that can be modified simultaneously is taken as n, the number of combinations, Sum, is shown in Equation 5:

[0174]

[0175] Once the combination to be modified is determined, the simulation process is first copied, and all initial values ​​of process parameters determined according to the design rules are adjusted. Each combination of initial value adjustments is then executed in different simulation processes.

[0176] Preferably, n∈[2, 10).

[0177] Furthermore, if it is detected that all combinations of corrected parameter values ​​converge after iterative calculation, a rationality assessment is performed, and the converged combinations are further screened and determined.

[0178] Once all the corrected initial value combinations converge, a rationality assessment is performed, because in the process calculation results, in addition to non-convergent devices, there are also devices that show abnormal prompts.

[0179] Because convergence is determined by the percentage of iterations that meet the standard, even if the results are converged, there may still be some degree of non-convergence in the actual iterative calculations, which may cause the device to issue an abnormal alert.

[0180] Because the output has been adjusted, the program scheme that was originally convergent may now show signs of non-convergence, so appropriate verification and evaluation are required.

[0181] Preferably, the rationality assessment includes: the number of abnormal prompting devices in the chemical process simulation program and / or the number of abnormal prompts for each device and / or the magnitude of parameter correction changes.

[0182] Specifically, if multiple combinations of modified initial values ​​converge simultaneously, the combination with fewer abnormal prompts from the chemical process simulation program and / or fewer abnormal prompts from each device and / or smaller parameter modification ranges is selected as the final parameter values ​​for the chemical process, thus determining the final designed process.

[0183] The application of this correction method reduces the difficulty of the initial value adjustment process and improves the efficiency of the separation process design for naphtha cracking to ethylene by transforming serial operations into parallel operations. Without the correction method described in this embodiment, when a process change is required, designers would need to spend about a week adjusting the process simulation parameters to achieve process convergence. By using this strategy for assisted design, the initial parameter design process is automatically completed to obtain a converged chemical process simulation program, which only takes about half a day. This can quickly support changes in user requirements and the needs of enterprise marketing.

[0184] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for modifying initial values of parameters of a chemical process simulation program, the method comprising: performing iterative calculation based on initial values of a plurality of parameters inputted into the simulation program; determining whether the result of the iterative calculation converges; if the result of the iterative calculation does not converge, determining a parameter to be modified and a modification value of the parameter to be modified from the plurality of parameters; the parameters including equipment parameters of equipment required for completing the chemical process; if the result of the iterative calculation does not converge, determining, based on the result of the iterative calculation, an equipment that does not converge and equipment information of the equipment that does not converge; determining, based on the result of the iterative calculation and the equipment information of the equipment that does not converge, an equipment parameter to be modified and a modification value of the equipment parameter to be modified; the simulation program corresponding to a standard operation database in which results of standard operations under a plurality of different equipment parameter conditions are set, comparing an actual operation result with theoretical operation result information in the standard operation database, and selecting, within a deviation allowable range, a parameter that exceeds the deviation allowable range, determining the parameter that exceeds the deviation allowable range as the parameter to be modified, and determining a modification target value of the parameter to be modified based on an actual deviation; replacing the initial value of at least one parameter to be modified with the corresponding modification value, and performing iterative calculation again to determine whether the result of the iterative calculation converges; if the result of the iterative calculation of the modification value of the equipment parameter still does not converge, returning to the above steps to determine again the equipment that does not converge and the equipment information of the equipment that does not converge; and if the result of the iterative calculation of the modification value of the equipment parameter converges, determining the modification value of the equipment parameter as a final equipment parameter value. the result of the iterative calculation including operation results of each equipment corresponding to the parameters and operation results of the chemical process; the equipment corresponding to the operation results that do not converge being the equipment that does not converge in the simulation program; the equipment information of the equipment that does not converge including a type of the equipment that does not converge. determining, based on the equipment information of the equipment that does not converge, a reason why the iterative calculation based on the initial values of the parameters does not converge through the standard operation database; the reason why the iterative calculation does not converge including that the equipment parameter does not meet a design specification; determining, based on the reason why the iterative calculation does not converge, the equipment parameter to be modified and the modification value of the equipment parameter to be modified; the determining of the equipment parameter to be modified and the modification value of the equipment parameter to be modified including determining the modification value of the equipment parameter based on a preset standard; and if it is detected that the equipment parameter does not meet the preset standard, determining the modification value of the parameter based on the preset standard. the equipment parameter not meeting the preset standard including unreasonable application of the equipment and / or abnormal function of the equipment; if it is detected that the function of the equipment is not fully enabled, determining that the application of the equipment is unreasonable; if it is detected that there is flow information that cannot be accurately detected in the equipment, determining that the function of the equipment is abnormal. the parameters further including process parameters of the chemical process; the result of the iterative calculation including operation results of each equipment corresponding to the parameters and operation results of the chemical process; and if the result of the iterative calculation does not converge, determining, based on the result of the iterative calculation, the process parameter to be modified and the modification value of the process parameter to be modified.

2. The parameter value correction method of a chemical process simulation program according to claim 1, characterized in that, ​ ​ ​ 3. The method according to claim 1, wherein the method is characterized by, ​ ​ ​ ​ ​ 4. The parameter value correction method of a chemical process simulation program according to claim 3, characterized in that, ​ ​ ​ 5. The parameter value correction method of a chemical process simulation program according to claim 1, characterized by, ​ ​ ​ 6. The parameter value correction method of a chemical process simulation program according to claim 5, characterized in that, The simulation program is preset with a correction coefficient determination criterion of the process parameters, and the correction coefficient of the process parameters is determined according to the correction coefficient determination criterion of the process parameters; According to the results of the iterative calculation, the correction value of the process parameter to be corrected is determined through the correction coefficient of the process parameter; The cause of the non-convergence includes that the initial value of the process parameter is adjusted and changed; When the initial value of the process parameter is adjusted and changed, the correction value is determined according to the correction coefficient of the process parameter; The correction coefficient of the process parameter is determined according to the correction coefficient determination criterion of the process parameter, which includes that the corresponding correction coefficient is determined according to the change amplitude of the process parameter compared with the initial process parameter, and then the correction value of the process parameter to be corrected is determined; The correction coefficient of the process parameter is determined according to the correction coefficient determination criterion of the process parameter, which includes that the corresponding correction coefficient is determined according to the change amplitude of the process parameter compared with the initial process parameter, and then the correction value of the process parameter to be corrected is determined.

7. The parameter value correction method of a chemical process simulation program according to claim 5 or 6, characterized in that, The initial value of the at least one process parameter to be corrected is replaced by the corresponding correction value, and the iterative calculation is performed again, which includes: After receiving the signal of the parameter value correction completion, the at least one parameter correction value is run in the program for iterative calculation; It is detected whether the parameter correction value appears the non-convergence phenomenon in the calculation; If it is detected that one or more parameter correction values converge in the iterative calculation, the corresponding one or more process parameter correction values are determined as the final process parameter values.

8. The parameter value correction method of the chemical process simulation program according to claim 7, characterized in that, the one or more process parameter correction values are combined to form different schemes, and a plurality of different schemes are input into the chemical process simulation program in parallel and synchronously for iterative calculation to detect whether each scheme converges; the simulation program sets a maximum / minimum number of parameters N1 that can be modified at the same time to avoid too many schemes to reduce memory consumption; the N1 ∈ [2, 10).

9. The parameter value correction method of the chemical process simulation program according to claim 8, characterized in that, the method for determining the maximum / minimum number of parameters N1 that can be modified at the same time includes: if it is detected that the combined schemes of the modified parameter correction values all converge after the iterative calculation, the convergence of the combined schemes is further screened and determined through rationality evaluation; the content of the rationality evaluation includes the number of abnormal prompt devices in the chemical process simulation program and / or the number of abnormal prompts of each device and / or the change amplitude of the parameter correction; if there are multiple combined initial values after the correction that converge at the same time, the combined scheme with the smaller number of abnormal prompt devices in the chemical process simulation program and / or the smaller number of abnormal prompts of each device and / or the smaller amplitude of the modified parameter is preferentially selected as the final parameter value of the chemical process, and the final designed process is determined.

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