Circulating stream unblocking method for process simulation

Abstract

A circulating stream unblocking method for process simulation. The method comprises: S1, acquiring an initial value of a feed stream and an initial value of a circulating stream (S1); S2, on the basis of the initial value of the feed stream and the initial value of the circulating stream, acquiring deviation values of all streams (S2); S3, receiving a connectivity degree, using the deviation value of a stream as a previous-round deviation value, and on the basis of the connectivity degree and the previous-round deviation value, obtaining a current-round deviation value and a current-round connectivity equation (S3); S4, combining the current-round connectivity equation and a first equation set to obtain simultaneous equations, and solving the simultaneous equations; if a convergence condition is met, receiving a new connectivity degree, using the current-round deviation value as a new previous-round deviation value, and on the basis of the new connectivity degree and the new previous-round deviation value, obtaining a new current-round deviation value and a new current-round connectivity equation; and if the convergence condition is not met, receiving a new connectivity degree, and on the basis of the new connectivity degree and the previous-round deviation value, obtaining a new current-round deviation value and a new current-round connectivity equation (S4); and S5, repeating S4-S5 until the new current-round deviation value is 0 (S5).

Description

A method for opening up circulation streams in process simulation Technical Field

[0001] The present invention relates to the technical field of chemical simulation, and in particular to a method for opening up circulating streams in process simulation. Background Art

[0002] The method for connecting circulating streams in traditional steady-state process simulation software is: first, break the circulating stream into circulating inlet and circulating outlet streams, then assign an initial value to the circulating inlet stream and solve it, compare the information of the two streams after solution, and if the two results are consistent, merge the two streams into one stream to achieve the connection of the streams.

[0003] However, if the results of the two streams differ significantly, the result of the loop outlet stream will be used as the initial value for the next run to solve the loop inlet stream, and the solution will be repeated multiple times until the two results are close enough to achieve the loop stream connection. The loop stream connection method of traditional steady-state process simulation software relies too much on human experience in judging the disconnection position of the loop stream and the standard for the closeness of the information of the two streams. For systems with many components and complex processes, as well as unreasonable location selection and unreasonable loop initial values, even a small deviation will cause the loop to fail to open, and it is difficult to deal with related problems relying on human experience; in addition, for multi-loop processes, when the traditional method opens the next loop, the already opened loop may fail to converge again due to changes in conditions. Summary of the Invention

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for opening up a circulating flow stream in a process simulation.

[0005] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0006] An embodiment of the present invention provides a method for opening up a circulating flow stream in a process simulation, comprising:

[0007] S1. Obtaining the initial values ​​of the feed stream and the initial values ​​of the circulation stream in the strict mechanism model corresponding to the specified chemical production process;

[0008] S2. Based on the initial values ​​of the feed stream and the initial values ​​of the circulating stream, obtain the deviation values ​​of all streams in the strict mechanism model;

[0009] S3. Receive the connectivity degree set by the user for any stream in the strict mechanism model, use the deviation value of the stream as the previous round deviation value, and obtain the current round deviation value and current round connection equation corresponding to the stream based on the connectivity degree and the previous round deviation value corresponding to the stream.

[0010] S4. Simultaneously solve the connection equations of the current round corresponding to the stream and the first set of equations obtained in advance to obtain simultaneous equations, obtain a solution, and determine whether the solution satisfies the convergence condition;

[0011] If the convergence condition is met, the new connectivity degree after the user increases the connectivity degree of the stream is received, and the current round deviation value corresponding to the stream is used as the new previous round deviation value. Based on the new connectivity degree and the new previous round deviation value, the new current round deviation value and current round connection equation corresponding to the stream are obtained;

[0012] If the convergence condition is not met, the new connectivity set by the user for the stream is received, and based on the new connectivity and the deviation value of the previous round, the new deviation value and connection equation of the current round corresponding to the stream are obtained;

[0013] S5. Repeat steps S4-S5 until the new deviation value of this round corresponding to the flow stream is 0.

[0014] Preferably, the S2 specifically includes:

[0015] S21. Based on the initial values ​​of the feed stream and the initial values ​​of the circulating stream, calculate the modules that meet the first condition in the strict mechanism model corresponding to the specified chemical production process to obtain the outlet variable of each module that meets the first condition;

[0016] S22. Based on the export variable of any module that meets the first condition, obtain the import variable of the downstream module of the module;

[0017] S23. Filter out modules that meet the first condition from the downstream modules of each module that meets the first condition, and obtain the export variables of the modules based on the import variables of the filter-out modules;

[0018] S24. Repeat S22-S24 until the inlet variables and outlet variables of each module and the deviation value of each stream in the strict mechanism model corresponding to the specified chemical production process are obtained.

[0019] Preferably,

[0020] The first condition is that the module's entry variables are complete.

[0021] Preferably,

[0022] The deviation value of the stream in S24 is equal to the difference obtained by subtracting the inlet variable of the downstream module of the stream from the outlet variable of the upstream module of the stream.

[0023] Preferably, the current round deviation value corresponding to the stream in S3 is obtained based on the connectivity and the previous round deviation value corresponding to the stream, using formula (1);

[0024] Wherein, formula (1) is:

[0025] Deviation value of this round = Deviation value of previous round × (1-connectivity);

[0026] Among them, the connection equation corresponding to this flow is:

[0027] 0 = the outlet variable of the upstream module of the stream - the inlet variable of the downstream module of the stream - the deviation value of this round.

[0028] Preferably,

[0029] The first set of equations includes the current round connection equations of all streams except the stream in the strict mechanism model corresponding to the specified chemical production process and the given conditions corresponding to all modules in the specified chemical production process.

[0030] Preferably,

[0031] The convergence condition is that the residual of the simultaneous equations is less than a preset tolerance value.

[0032] Preferably, the method further comprises:

[0033] S6. Obtain the connection equations corresponding to each stream in the strict mechanism model corresponding to the currently specified chemical production process, and then solve them together with the first set of equations to obtain the inlet flow rate of the downstream module of the circulating stream:

[0034] The connection equation corresponding to each stream in the strict mechanism model corresponding to the currently specified chemical production process is: 0 = the outlet variable of the upstream module of the stream - the inlet variable of the downstream module of the stream.

[0035] Preferably,

[0036] In S3, when the downstream module of the flow stream is the first module, the user sets the connectivity of the flow stream to 0.5;

[0037] The first module is any one of a heater, a flash tank, a mixer and a splitter.

[0038] Preferably,

[0039] In S4, if the solution result does not meet the convergence condition, when the downstream module of the flow stream is the first module, the new connectivity set by the receiving user for the first flow stream is 1; when the downstream module of the flow stream is not the first module, the new connectivity after the connectivity of the flow stream is reduced by the receiving user.

[0040] The beneficial effects of the present invention are: a process simulation circulating stream opening method of the present invention can obtain the deviation values ​​of all streams in the strict mechanism model based on the initial value of the feed stream and the initial value of the circulating stream, and receive the connectivity set by the user for any stream in the strict mechanism model, and use the deviation value of the stream as the previous round deviation value, and based on the connectivity and the previous round deviation value corresponding to the stream, obtain the current round deviation value and current round connection equation corresponding to the stream, and finally continuously adjust the connectivity to gradually reduce the current round deviation value to achieve process opening, which can effectively reduce the repetitive work of modelers in opening the cycle and improve the efficiency of process opening. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG1 is a flow chart of a process simulation circulating stream opening method of the present invention;

[0042] FIG2 is a flow chart of the process in the strict mechanism model corresponding to the chemical production process specified in the embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0044] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0045] It should be noted that the circulating stream refers to the stream that flows back from the outlet to the inlet of a specified chemical production process and participates in the next processing.

[0046] 1 , this embodiment provides a method for opening up a circulating flow stream in a process simulation, including:

[0047] S1. Obtaining the initial values ​​of the feed stream and the initial values ​​of the circulation stream in the strict mechanism model corresponding to the specified chemical production process;

[0048] In this embodiment, the initial values ​​of the feed stream and the initial values ​​of the circulation stream are both set by the user.

[0049] In the specific application of this embodiment, for example, see FIG2 , which is a flow chart of a process in a strict mechanism model corresponding to a specified chemical production process. B1, B2, B3, B4, and B5 are modules in the strict mechanism model, and each module represents a process in the specified chemical production process, such as a reactor module for performing chemical reactions, such as a batch reactor or a continuous flow reactor; a distillation tower module for separating a mixture into different components by distillation; a separator module for separating a multiphase mixture into different phases, such as liquid-liquid separation or solid-liquid separation; a compressor module for compressing gas to increase pressure, etc. Each module has corresponding given conditions. For example, the given conditions of the reactor module (given conditions are artificially pre-set and are used to calculate the calculation conditions for the module execution process) include the specified reaction temperature, pressure, reactor volume, and the corresponding reaction, as well as the calculation method for the reactor module to execute the corresponding process.

[0050] For example, in Figure 2, 2 represents stream 2, 3 represents stream 3, 6 represents stream 6, 8 represents stream 8, and so on. Module B1, stream 2, module B2, stream 3, module B3, and stream 8 form a loop. Stream 8 is the circulating stream; 1 represents feed stream 1, 5 represents feed stream 5, 4 represents discharge stream 4, and 7 represents discharge stream 7. Streams are used to describe the connections between modules in a chemical process flow.

[0051] S2. Based on the initial values ​​of the feed stream and the initial values ​​of the circulating stream, obtain the deviation values ​​of all streams in the strict mechanism model.

[0052] In the specific application of this embodiment, S2 specifically includes:

[0053] S21. Based on the initial values ​​of the feed stream and the initial values ​​of the circulating stream, calculations are performed on the modules that meet the first condition in the strict mechanism model corresponding to the specified chemical production process to obtain the export variables of each module that meets the first condition.

[0054] The first condition is that the module's entry variables are complete. For example, as shown in Figure 2, module B1 has two entry variables: feed stream 1 entering module B1 and recycle stream 8 entering module B1. Both of these variables have been initialized by the user. Therefore, module B1's entry variables are complete, and module B1 meets the first condition. Similarly, module B4 also meets the first condition.

[0055] S22. Based on the export variable of any module that meets the first condition, obtain the import variable of the downstream module of the module.

[0056] S23. Filter out modules that meet the first condition from the downstream modules of each module that meets the first condition, and obtain the export variable of the module based on the import variable of the filtered module.

[0057] S24. Repeat S22-S24 until the inlet variables and outlet variables of each module and the deviation value of each stream in the strict mechanism model corresponding to the specified chemical production process are obtained.

[0058] The deviation value of the stream in S24 is equal to the difference obtained by subtracting the inlet variable of the downstream module of the stream from the outlet variable of the upstream module of the stream.

[0059] In this embodiment, the user-specified calculation conditions in the strict mechanism model corresponding to the specified chemical production process are complete. The calculation conditions include the given conditions in each module and the values ​​of the stream variables in feed streams 1 and 5 and circulating stream 8. Modules in the strict mechanism model corresponding to the specified chemical production process that meet the first condition (because feed streams 1 and 5 have initial values ​​and circulating stream 8 also has an initial value, the inlet variables of module B1 are complete, that is, the inlet variables are all known. Similarly, the inlet variables of module B4 are complete, so modules B1 and B4 meet the first condition) are calculated to obtain the outlet variables of modules B1 and B4, that is, the upstream variables of streams 2 and 6. The outlet variables of modules B1 and B4 are used as the inlet variables of modules B2 and B5, respectively. At this time, the entry variables of module B2 are complete, so the upstream variables of stream 3 and stream 9, that is, the exit variables of module B2, can be solved. Then, the upstream variables of stream 3 and stream 9 are assigned to the downstream variables. At this time, the entry variables of module B3 and module B5 are complete, and the exit variables of module B3 and module B5 (that is, the upstream variables of stream 4, stream 7, and stream 8) can be solved.

[0060] S3. Receive the connectivity set by the user for any stream in the strict mechanism model, and use the deviation value of the stream as the previous round deviation value. Based on the connectivity and the previous round deviation value corresponding to the stream, obtain the current round deviation value and current round connection equation corresponding to the stream.

[0061] In the actual application of this embodiment, the current round deviation value corresponding to the stream in S3 is obtained based on the connectivity and the previous round deviation value corresponding to the stream, using formula (1);

[0062] Wherein, formula (1) is:

[0063] Deviation value of this round = Deviation value of previous round × (1-connectivity);

[0064] Among them, the connection equation corresponding to this flow is:

[0065] 0 = the outlet variable of the upstream module of the stream - the inlet variable of the downstream module of the stream - the deviation value of this round.

[0066] For example, the deviation value of stream 8 obtained in S2 is used as the deviation value of the previous round. If the connection assumption set by the user for stream 8 is 0.2, then the deviation value of this round = the deviation value of the previous round × (1-0.2).

[0067] S4. Simultaneously solve the connection equations of the current round corresponding to the stream and the first set of equations obtained in advance to obtain simultaneous equations, obtain a solution, and determine whether the solution satisfies the convergence condition;

[0068] In this embodiment, the first set of equations includes the current round connection equations of all streams except the stream in the strict mechanism model corresponding to the specified chemical production process and the given conditions corresponding to all modules in the specified chemical production process.

[0069] The convergence condition is that the residual of the simultaneous equations is less than a preset tolerance value.

[0070] If the convergence conditions are met, the new connectivity degree after the receiving user increases the connectivity degree of the flow stream (that is, the new connectivity degree after the receiving user increases the connectivity degree of the flow stream. For example, the connectivity degree of the flow stream is 0.5, and the new connectivity degree after the receiving user increases the connectivity degree of the flow stream by 0.5 (for example, 0.1), then the new connectivity degree is 0.6), and the current round deviation value corresponding to the flow stream is used as the new previous round deviation value, and based on the new connectivity and the new previous round deviation value, the new current round deviation value and current round connection equation corresponding to the flow stream are obtained.

[0071] If the convergence condition is not met, the new connectivity set by the receiving user for the flow stream is received (that is, a new connectivity set by the receiving user for the flow stream), and based on the new connectivity and the previous round deviation value, the new current round deviation value and current round connection equation corresponding to the flow stream are obtained.

[0072] S5. Repeat steps S4-S5 until the new current round deviation value corresponding to the flow stream is 0. In this embodiment, the process is considered to be connected when the new current round deviation value is 0.

[0073] In practical applications, the method further includes:

[0074] S6. Obtain the connection equation corresponding to each stream in the strict mechanism model corresponding to the currently specified chemical production process, and then solve it together with the first set of equations to obtain the inlet flow of the downstream module of the circulating stream.

[0075] The connection equation corresponding to each stream in the strict mechanism model corresponding to the currently specified chemical production process is: 0 = the outlet variable of the upstream module of the stream - the inlet variable of the downstream module of the stream.

[0076] In this embodiment, after the connection is established, the convergence result of the simultaneous equation solution when the new connection degree is 1 is loaded into the circulating stream 8 with a given initial value, which provides the initial value for the next solution and can achieve convergence more quickly.

[0077] In a specific implementation of this embodiment, in S3, when the downstream module of the stream is the first module, the connectivity set by the user for the stream is 0.5; wherein the first module is any one of: a heater, a flash tank, a mixer, and a splitter.

[0078] In another specific implementation of this embodiment, in S4, if the solution result does not meet the convergence condition, when the downstream module of the flow stream is the first module, the new connectivity set by the receiving user for the first flow stream is 1; when the downstream module of the flow stream is not the first module, the new connectivity after the connectivity of the flow stream is reduced by the receiving user.

[0079] In this example, when assigning connectivity values ​​to streams, the user can assign the same value to all streams. Alternatively, for some simple modules, the connectivity can be quickly adjusted to 1 without causing model convergence failure. The user automatically assigns a connectivity value of 0.5 to the entry stream of the first module and 1 to the second simultaneous solution. This allows for faster connection of some streams and improves overall model convergence. The connectivity values ​​of the remaining modules remain user-configured.

[0080] A process simulation circulating stream opening method of the present invention can obtain the deviation values ​​of all streams in the strict mechanism model based on the initial value of the feed stream and the initial value of the circulating stream, and receive the connectivity set by the user for any stream in the strict mechanism model, and use the deviation value of the stream as the previous round deviation value, and based on the connectivity and the previous round deviation value corresponding to the stream, obtain the current round deviation value and current round connection equation corresponding to the stream, and finally continuously adjust the connectivity to gradually reduce the current round deviation value to achieve process opening, which can effectively reduce the repetitive work of modelers in opening the cycle and improve the efficiency of process opening.

[0081] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0082] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0083] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0084] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0085] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for opening up a process simulation circulation stream, characterized in that: include: S1. Obtaining the initial value of the feed stream and the initial value of the circulating stream in the strict mechanism model corresponding to the specified chemical production process; S2. Based on the initial value of the feed stream and the initial value of the circulating stream, obtain the deviation value of all streams in the strict mechanism model; S3, receiving the connection degree set by the user for any flow stock in the strict mechanism model, and taking the deviation value of the flow stock as the previous round deviation value, and obtaining the current round deviation value and the current round connection equation corresponding to the flow stock based on the connection degree and the previous round deviation value corresponding to the flow stock; S4, combining the connection equation of the current round corresponding to the stream with the first set of equations obtained in advance to obtain simultaneous equations and solving them to obtain a solution result, and judging whether the solution result meets the convergence condition; If the convergence condition is met, the new connectivity degree after the connectivity degree of the stream is increased by the user is received, and the current round deviation value corresponding to the stream is used as the new previous round deviation value, and based on the new connectivity degree and the new previous round deviation value, the new current round deviation value and the current round connection equation corresponding to the stream are obtained; If the convergence condition is not met, the new connectivity set by the user for the stream is received, and based on the new connectivity and the previous round deviation value, a new current round deviation value and current round connection equation corresponding to the stream are obtained; S5. Repeat steps S4-S5 until the new deviation value of this round corresponding to the flow stock is 0.

2. The process simulation circulation stream opening method according to claim 1 is characterized in that: The S2 specifically includes: S21, based on the initial value of the feed stream and the initial value of the circulating stream, calculate the modules that meet the first condition in the strict mechanism model corresponding to the specified chemical production process to obtain the export variable of each module that meets the first condition; S22, based on the export variable of any module that meets the first condition, obtaining the import variable of the downstream module of the module; S23, screening out modules that meet the first condition from the downstream modules of each module that meets the first condition, and obtaining the export variable of the module according to the input variable of the screened out module; S24. Repeat S22-S24 until the inlet variables and outlet variables of each module and the deviation value of each stream in the strict mechanism model corresponding to the specified chemical production process are obtained.

3. The process simulation circulation stream opening method according to claim 2 is characterized in that: The first condition is that the module's entry variables are complete.

4. The process simulation circulation stream opening method according to claim 3 is characterized in that: The deviation value of the stream in S24 is equal to the difference obtained by subtracting the inlet variable of the downstream module of the stream from the outlet variable of the upstream module of the stream.

5. The process simulation circulation stream opening method according to claim 4 is characterized in that: The current round deviation value corresponding to the stream in S3 is obtained based on the connection degree and the previous round deviation value corresponding to the stream, using formula (1); Wherein, formula (1) is: Deviation value of this round = deviation value of previous round × (1-connectivity); Among them, the connection equation for this round corresponding to the flow is: 0 = the outlet variable of the upstream module of the stream - the inlet variable of the downstream module of the stream - the deviation value of this round.

6. The process simulation circulation stream opening method according to claim 5 is characterized in that: The first set of equations includes the current round connection equations of all streams except the stream in the strict mechanism model corresponding to the specified chemical production process and the given conditions corresponding to all modules in the specified chemical production process.

7. The process simulation circulation stream opening method according to claim 6 is characterized in that: The convergence condition is that the residual of the simultaneous equations is less than a preset tolerance value.

8. The process simulation circulation stream opening method according to claim 7 is characterized in that: The method further comprises: S6. Obtain the connection equation corresponding to each stream in the strict mechanism model corresponding to the currently specified chemical production process, and then solve it together with the first set of equations to obtain the inlet flow rate of the downstream module of the circulating stream: The connection equation corresponding to each stream in the strict mechanism model corresponding to the currently specified chemical production process is: 0 = the outlet variable of the upstream module of the stream - the inlet variable of the downstream module of the stream.

9. The process simulation circulation stream opening method according to claim 8, characterized in that: In S3, when the downstream module of the flow stream is the first module, the connectivity set by the user for the flow stream is 0.5; The first module is any one of a heater, a flash tank, a mixer and a splitter.

10. The process simulation circulation stream opening method according to claim 9, characterized in that: In S4, if the solution result does not meet the convergence condition, when the downstream module of the flow stream is the first module, the new connectivity set by the receiving user for the first flow stream is 1; when the downstream module of the flow stream is not the first module, the new connectivity after the connectivity of the flow stream is reduced by the receiving user.

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