Simulation method for production process of refined naphthalene crystal

Abstract

The simulation method of the refined naphthalene crystallization production procedure sets the end of each operation step sequence and the start of the next operation step sequence as the trigger event, establishes the blocking queue based on the trigger event according to the expected end time of each operation step sequence, and advances the simulation process through the established blocking queue. The simulation method of the refined naphthalene crystallization production procedure sets the blocking queue based on the trigger event, establishes the simulation process advancing mode based on the blocking queue, and sets the blocking queue in real-time updating mode. The simulation method can realize the continuous and dynamic characteristics of the industrial equipment operation, and can realize the time uncertainty of the event generation, equipment occupation and operation, and can provide a basic platform for the subsequent simulation strategy research and optimization.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of refined naphthalene production, and particularly relates to a simulation method for a refined naphthalene crystallization production procedure. BACKGROUND

[0002] The downstream application of refined naphthalene is dye and organic dye intermediate. China is the largest dye and organic dye producer in the world. In recent years, the demand for refined naphthalene in China has been continuously increasing, and the production of refined naphthalene is mainly obtained through multi-step crystallization of industrial naphthalene. The production process of refined naphthalene has seven steps, which are concentration two (C2), concentration one (C1), purification one (P1), purification two (P2), purification three (P3), purification four (P4), and purification five (P5). The crystallization process of each step includes feeding, crystallization, discharge, sweating, and feeding and melting, and the concentration process has two crystallization processes, and the two processes are different. There are three groups of crystallization tanks on site, each process is carried out in a crystallization tank, and only one process can be run at a time, and the process that can be carried out in each group of crystallization tanks is limited.

[0003] RE-7101A / B tank (B1) runs: purification first step, concentration first step, and concentration second step.

[0004] RE-7102A / B tank (B2) runs: purification second step to fifth step.

[0005] RE-7103A / B tank (B3) runs: purification first step to second step.

[0006] Each intermediate product has a corresponding intermediate tank for collection, and the feeding, discharge, sweating, and discharge of all processes are all into the specified tank, and the material flow diagram is as shown in Figure 1 .

[0007] The crystallization time is mainly affected by the quality of raw materials, the number of processes to be executed, temperature, etc. Figure 2 The relationship between the required time and temperature of each process of C2 step at a certain time is shown in the schematic diagram, and when the environmental temperature and the quality of raw materials change, the curve will change.

[0008] Since the crystallization time is long or short, the material tank position in the intermediate tank changes frequently, and it is necessary to reasonably select which process to run in the crystallization tank to ensure that the material in the intermediate tank meets the production requirements and does not cause the crystallization program to be suspended due to the influence of the tank position.

[0009] Since the parameters of crystallization are inconsistent, the crystallization time of each step is different. This further increases the complexity of the crystallization process scheduling.

[0010] It is evident that the operation of industrial equipment is continuous and dynamic. At the same time, the generation of tasks, equipment occupancy, and operation introduce temporal uncertainty into events. How to balance these two characteristics of the process flow and select an appropriate simulation strategy is a crucial issue in the development of a computer simulation system for this process flow. Furthermore, when studying how to establish and optimize scheduling strategies, it is first necessary to establish a production system structure that allows for scheduling strategy research. Conversely, how to construct a refined naphthalene crystallization production system structure that facilitates scheduling strategy research is also the primary problem to be solved.

[0011] Invention application No. 201610147402.3 discloses "a process-based parallel scheduling method for simulation tasks": For the architecture of multi-processor plug-in embedded devices, a simulation management process is started as the main process on a PC. The main process creates several child process virtual real-time processor plug-ins. The main process creates scheduling and shared memory. After all child processes have completed initialization, the main process starts a single-cycle simulation start flag. Each child process reads the simulation start flag from the scheduling shared memory, starts task computation, and sets the child process task computation end flag after the task is completed, then enters a waiting state. The main process summarizes the end flags of all child processes, issues the start flag for the next cycle, and repeats the process until the set maximum number of simulation runs is reached, at which point the process exits.

[0012] Application No. 201811063502.3 discloses "a scheduling simulation system and scheduling simulation method", comprising: an event flow controller for sequentially reading an event from an event flow and generating an event request; a unified data interface for receiving the event request and storing the status information of the event request; a scheduler for monitoring the status information of the event request, allocating nodes according to the event request, and updating the status information of the event request; and a simulation node module for monitoring the status information of the event request, performing simulation processing, and updating the status information of the event request.

[0013] The invention application with application number 202011341455.1 discloses "a method, device, equipment, and medium for advancing simulation time of a continuous-discrete hybrid system". The method includes: for advancing the simulation time of a continuous system, the entire system advances the simulation time according to a minimum step size, wherein the time advancement step size of the simulation object is an integer multiple of the minimum step size; for discrete events, the events are divided into synchronous events and asynchronous events. Synchronous events are executed immediately after they are generated, and asynchronous events are sorted in the event queue according to the timestamp size. When the simulation time advances to the timestamp, the asynchronous events are scheduled and executed. The state of the simulation object changes as the simulation time advances. This method combines the advantages of time stepping and event advancement, broadens the application scope, and improves the efficiency of simulation advancement and scheduling.

[0014] Invention application No. 202011517078.2 discloses "a multi-threaded and multi-process integrated simulation model component scheduling method and system," which includes a simulation model component host reporting information and status of simulation model components of distributed simulation nodes to a simulation model component monitor and a simulation model component scheduling engine; the simulation model component monitor loading a local simulation model component configuration file, receiving information and status of simulation model components reported by each distributed simulation model component host, and generating a simulation model component scheduling configuration file; the simulation model component scheduling engine loading a local simulation model component configuration file, receiving information and status of simulation model components reported by each distributed simulation model component host, loading the simulation model component scheduling configuration file, and initializing the scheduling mode of the simulation model components; the scheduling engine and the host create simulation model instances, schedule simulation model advancement, and send and receive simulation interaction messages and events through the simulation model component application interface. Summary of the Invention

[0015] To address the above problems, this invention provides a simulation method for the production process of refined naphthalene crystallization, the specific technical solution of which is as follows:

[0016] A simulation method for a refined naphthalene crystallization production process, characterized in that:

[0017] In the production of refined naphthalene crystallization, the end of each sub-process or the start of the next sub-process is set as the trigger event.

[0018] The simulation process is advanced based on the set trigger events.

[0019] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0020] The process of advancing the simulation based on the set trigger events is specifically as follows:

[0021] Based on the expected completion time of each sub-process of each process, bottleneck points are established, thus forming a bottleneck point sequence for each process.

[0022] Establish a blocking queue based on the sequence of blocking points for each process and the execution order between processes;

[0023] The simulation process is advanced based on the sequence of bottlenecks in each process.

[0024] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0025] The blocking queue is updated according to changes in the defined state space.

[0026] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0027] The state space is constructed based on defined objects, namely the crystallization box and intermediate buffer tank involved in the production of refined naphthalene crystallization.

[0028] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0029] The crystallization boxes are configured to have 3 units.

[0030] in,

[0031] The first crystallization box is used for the first step of purification process, the first step of concentration process, and the second step of concentration process.

[0032] The second crystallization box is used for the purification of the second, third, fourth and fifth steps of the process.

[0033] The third crystallization box is used for the purification of the first step and the purification of the second step.

[0034] Based on this, a simulation structure was established that features multiple parallel processes and serial processes within each parallel thread.

[0035] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0036] The state space includes: the liquid level of each crystallization tank, the liquid level of each buffer tank, the operating status of each crystallization tank, and the operating time.

[0037] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0038] When each triggering event is triggered, the state space is determined and updated;

[0039] The blocking queue is updated based on the determination and update of the state space.

[0040] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0041] When each triggering event is triggered, the state space is determined and updated;

[0042] The blocking queue is updated based on the determination and update of the state space.

[0043] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0044] The update of the blocking queue includes:

[0045] Reconfiguration and update at the end of any process;

[0046] The corresponding blocking point is deleted and updated when any sub-process ends;

[0047] Delay update when any sub-process needs to be postponed.

[0048] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0049] When constructing the blocking queue, if the next process is a subsequent process of the previous process, a material replenishment blocking point is constructed; otherwise, a blocking point is constructed in the manner of first discharging and then feeding.

[0050] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0051] The determination of the state space is based on a set scheduling rule base; specifically:

[0052] When each triggering event is triggered, a determination is made as to whether it conforms to the scheduling rule base.

[0053] If the conditions are met, the corresponding sub-process is executed; otherwise, the corresponding sub-process is postponed.

[0054] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0055] The scheduling rule base is established based on five dimensions: factory level, crystallizer level, buffer tank level, process level, and process operation sequence level.

[0056] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0057] Whether a rule conforms to the scheduling rule base is determined as follows:

[0058] First, determine whether a delay is necessary at both the factory level and the crystallization chamber level.

[0059] If a postponement is necessary due to limitations in the production environment, then it shall be postponed.

[0060] otherwise,

[0061] Determine the liquid level in the buffer tank corresponding to the next sub-process, and determine whether it needs to be postponed based on the determination result;

[0062] If it is feeding or replenishing, the buffer tank is judged to see if the liquid level is insufficient according to the first judgment rule set; if the judgment result is that the liquid level in the buffer tank is insufficient, the sub-process is postponed.

[0063] If it is a discharge, sweating, or discharge process, the buffer tank is judged to determine whether the liquid level is insufficient according to the second judgment rule. If the judgment result is that the liquid level in the buffer tank is insufficient, the sub-process is postponed.

[0064] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0065] The statement "If it is feeding or replenishing, then the buffer tank is judged to determine whether the liquid level is insufficient according to the set first judgment rule" specifically means:

[0066] Subtract the current liquid level in the buffer tank from the expected feed rate or the replenishment rate, and compare the result with the set low alarm liquid level in the buffer tank. If it is lower than the set low alarm liquid level in the buffer tank, postpone the subprocess; otherwise, update the liquid level in the buffer tank and the status of the crystallizer.

[0067] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0068] The statement "If it is discharge, sweating, or emission, then the buffer tank is judged to determine whether the liquid level margin is insufficient according to the set second judgment rule" specifically means:

[0069] Add the discharge volume of the corresponding crystallization box to the liquid level of the buffer tank, and compare the result with the set high alarm liquid level of the buffer tank.

[0070] If the sum of the values ​​exceeds the high alarm level of the buffer tank, it is determined that the buffer tank level is insufficient and the subprocess is postponed; otherwise, the buffer tank level and the crystallizer status are updated.

[0071] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0072] The aforementioned factory-level rules include whether or not the crystallization chamber is allowed to operate at less than full capacity.

[0073] A simulation method for a refined naphthalene crystallization production process according to the present invention is characterized in that:

[0074] The rules at the buffer tank level include the rules for adding raw materials to buffer tanks, as detailed below:

[0075] The following guidelines should be followed when adding raw materials:

[0076] V supple (t1, t2) = (t2 - t1) × v,

[0077] The following constraints apply to the addition of raw materials:

[0078] V supple (t1, t2) + V(A) raw ,t)≤U(A raw )-U high (A raw ),

[0079] in,

[0080] V supple (t1, t2): The amount of material replenished to the raw material buffer tank during time t1 to t2; unit: m 3 ;

[0081] t1: Feeding start time, unit: min;

[0082] t2: Replenishment end time, unit: min;

[0083] v: Feed rate, unit: m 3 / min;

[0084] V(A raw ,t): corresponding liquid level in the crystallization tank, unit: m 3 ;

[0085] U(A raw (): Buffer tank capacity, unit: m 3 ;

[0086] U high (A raw ): The highest liquid level set in the buffer tank, unit: m 3 .

[0087] The present invention provides a simulation method for a refined naphthalene crystallization production process. By setting up a blocking queue based on trigger events, a simulation process advancement mode based on the blocking queue is established, and the blocking queue is set in real time. Through this simulation method, the continuous and dynamic characteristics of industrial equipment operation can be achieved, while the generation of tasks, equipment occupation and operation, etc., have temporal uncertainty, thus taking into account both aspects. At the same time, it provides a basic platform for subsequent simulation strategy research and optimization. Attached Figure Description

[0088] Figure 1 This is a flowchart illustrating the process steps for producing refined naphthalene crystallization in this invention.

[0089] Figure 2 for Figure 1 A schematic diagram showing the time progression and temperature relationship of each process in the C2 step;

[0090] Figure 3 This is a schematic diagram illustrating the definition of objects and state space in this invention;

[0091] Figure 4 This is a schematic diagram of the event rules, material flow, and flow rate in the B1 box C2 process in this embodiment of the invention;

[0092] Figure 5This is a schematic diagram of the event rules, material flow, and flow rate in the B1 box C1 process of this invention embodiment;

[0093] Figure 6 This is a schematic diagram of the event rules, material flow, and flow rate in the B1 box P1 process of this invention embodiment;

[0094] Figure 7 This is a schematic diagram of the event rules, material flow, and flow rate in the B2 box P2 process in this embodiment of the invention;

[0095] Figure 8 This is a schematic diagram of the event rules, material flow and flow rate in the B2 box P3 process in this embodiment of the invention;

[0096] Figure 9 This is a schematic diagram of the event rules, material flow, and flow rate in the B2 box P4 process in this embodiment of the invention;

[0097] Figure 10 This is a schematic diagram of the event rules, material flow and flow rate in the B2 box P5 process in this embodiment of the invention;

[0098] Figure 11 This is a schematic diagram of the event rules, material flow, and flow rate in the B3 box P1 process in this embodiment of the invention.

[0099] Figure 12 This is a schematic diagram of the event rules, material flow, and flow rate in the P2 process of box B3 in this embodiment of the invention.

[0100] Figure 13 This is a schematic diagram of the multi-task parallel state update and blocking queue construction in this invention. Detailed Implementation

[0101] The following is a further detailed description of a simulation method for a refined naphthalene crystallization production process according to the present invention, based on the accompanying drawings and specific embodiments.

[0102] A simulation method for the production process of refined naphthalene crystallization.

[0103] In the production of refined naphthalene crystallization, the end of each sub-process or the start of the next sub-process is set as the trigger event.

[0104] The simulation process is advanced based on the set trigger events.

[0105] in,

[0106] The process of advancing the simulation based on the set trigger events is specifically as follows:

[0107] Based on the expected completion time of each sub-process of each process, bottleneck points are established, thus forming a bottleneck point sequence for each process.

[0108] Establish a blocking queue based on the sequence of blocking points for each process and the execution order between processes;

[0109] The simulation process is advanced based on the sequence of bottlenecks in each process.

[0110] in,

[0111] The blocking queue is updated according to changes in the defined state space.

[0112] in,

[0113] The state space is constructed based on defined objects, namely the crystallization box and intermediate buffer tank involved in the production of refined naphthalene crystallization.

[0114] in,

[0115] The crystallization boxes are configured to have 3 units.

[0116] in,

[0117] The first crystallization box is used for the first step of purification process, the first step of concentration process, and the second step of concentration process.

[0118] The second crystallization box is used for the purification of the second, third, fourth and fifth steps of the process.

[0119] The third crystallization box is used for the purification of the first step and the purification of the second step.

[0120] Based on this, a simulation structure was established that features multiple parallel processes and serial processes within each parallel thread.

[0121] in,

[0122] The state space includes: the liquid level of each crystallization tank, the liquid level of each buffer tank, the operating status of each crystallization tank, and the operating time.

[0123] in,

[0124] When each triggering event is triggered, the state space is determined and updated;

[0125] The blocking queue is updated based on the determination and update of the state space.

[0126] in,

[0127] When each triggering event is triggered, the state space is determined and updated;

[0128] The blocking queue is updated based on the determination and update of the state space.

[0129] in,

[0130] The update of the blocking queue includes:

[0131] Reconfiguration and update at the end of any process;

[0132] The corresponding blocking point is deleted and updated when any sub-process ends;

[0133] Delay update when any sub-process needs to be postponed.

[0134] in,

[0135] When constructing the blocking queue, if the next process is a subsequent process of the previous process, a material replenishment blocking point is constructed; otherwise, a blocking point is constructed in the manner of first discharging and then feeding.

[0136] in,

[0137] The determination of the state space is based on a set scheduling rule base; specifically:

[0138] When each triggering event is triggered, a determination is made as to whether it conforms to the scheduling rule base.

[0139] If the conditions are met, the corresponding sub-process is executed; otherwise, the corresponding sub-process is postponed.

[0140] in,

[0141] The scheduling rule base is established based on five dimensions: factory level, crystallizer level, buffer tank level, process level, and process operation sequence level.

[0142] in,

[0143] Whether a rule conforms to the scheduling rule base is determined as follows:

[0144] First, determine whether a delay is necessary at both the factory level and the crystallization chamber level.

[0145] If a postponement is necessary due to limitations in the production environment, then it shall be postponed.

[0146] otherwise,

[0147] Determine the liquid level in the buffer tank corresponding to the next sub-process, and determine whether it needs to be postponed based on the determination result;

[0148] If it is feeding or replenishing, the buffer tank is judged to see if the liquid level is insufficient according to the first judgment rule set; if the judgment result is that the liquid level in the buffer tank is insufficient, the sub-process is postponed.

[0149] If it is a discharge, sweating, or discharge process, the buffer tank is judged to determine whether the liquid level is insufficient according to the second judgment rule. If the judgment result is that the liquid level in the buffer tank is insufficient, the sub-process is postponed.

[0150] in,

[0151] The statement "If it is feeding or replenishing, then the buffer tank is judged to determine whether the liquid level is insufficient according to the set first judgment rule" specifically means:

[0152] Subtract the current liquid level in the buffer tank from the expected feed rate or the replenishment rate, and compare the result with the set low alarm liquid level in the buffer tank. If it is lower than the set low alarm liquid level in the buffer tank, postpone the subprocess; otherwise, update the liquid level in the buffer tank and the status of the crystallizer.

[0153] in,

[0154] The statement "If it is discharge, sweating, or emission, then the buffer tank is judged to determine whether the liquid level margin is insufficient according to the set second judgment rule" specifically means:

[0155] Add the discharge volume of the corresponding crystallization box to the liquid level of the buffer tank, and compare the result with the set high alarm liquid level of the buffer tank.

[0156] If the sum of the values ​​exceeds the high alarm level of the buffer tank, it is determined that the buffer tank level is insufficient and the subprocess is postponed; otherwise, the buffer tank level and the crystallizer status are updated.

[0157] in,

[0158] The aforementioned factory-level rules include whether or not the crystallization box is allowed to operate at less than full load. This "included" here means, but is not limited to, the understanding that factory-level rules also include factors such as: malfunctions, maintenance, and production scheduling based on sales volume.

[0159] in,

[0160] The rules at the buffer tank level include the rules for adding raw materials to buffer tanks, as detailed below:

[0161] The following guidelines should be followed when adding raw materials:

[0162] V supple (t1, t2) = (t2 - t1) × v,

[0163] The following constraints apply to the addition of raw materials:

[0164] V supple (t1, t2) + V(A) raw ,t)≤U(A raw )-U high (A raw ),

[0165] in,

[0166] V supple(t1, t2): The amount of material replenished to the raw material buffer tank during time t1 to t2; unit: m 3 ;

[0167] t1: Feeding start time, unit: min;

[0168] t2: Replenishment end time, unit: min;

[0169] v: Feed rate, unit: m 3 / min;

[0170] V(A raw ,t): corresponding liquid level in the crystallization tank, unit: m 3 ;

[0171] U(A raw (): Buffer tank capacity, unit: m 3 ;

[0172] U high (A raw ): The highest liquid level set in the buffer tank, unit: m 3 .

[0173] Working principle, process and implementation examples

[0174] This embodiment illustrates the working principle and process by defining state space and events based on objects, establishing a material flow and scheduling rule base, and using an event-triggered model to handle liquid level and state updates.

[0175] (Step 1) Based on the actual production of Baowu charcoal materials (as shown in Figure 1), define the state space and events based on objects: Define the objects as: m crystallization boxes B that perform crystallization production. i (1≤i≤m) and n buffer slots A for storing intermediate products. j (1≤j≤n), specifically 3 crystallization boxes B1, B2, and B3, and 9 buffer slots.

[0176] A 10 A 11 A 12 A 13 A 14 A 15&20 A 16 A 17 A 18&19 ,like Figure 3 As shown; then the state space at a certain time t includes: the liquid level V(B) of each crystallization tank. i ,t)(1≤i≤3), running state s(B i ,t), running time t ran (B i,t) and the liquid level V(A) of each buffer tank j ,t)(10≤j≤18&19). Each process is considered as an event P, including: C2, C1, P1, P2, P3, P4, P5. The entry of liquid from the buffer tank of this process into the crystallization box is the start of the event. The discharge or evaporation of liquid during each process is discharged into the buffer tank of the previous or current process. The remaining crystals are melted and discharged into the buffer tank of the next process or wait for continuous replenishment as the end of the event.

[0177] (Step 2) Establish a material flow and scheduling rule base: Material flow is established based on three dimensions: material flow direction, material flow rate, and time; the scheduling rule base is established based on five dimensions: plant level, crystallizer level, buffer tank level, process level, and process operation sequence level; the material flow direction and flow rate are all carried out according to the rules of the scheduling rule base, serving as the principle for process execution; all rules constitute the rule base G, where the material flow direction of each step in each process is as follows: Figures 4 to 12 As shown; where time (unit: minutes), material flow, and flow rate (unit: tons) are all variable parameters, given by the scheduler. Based on the state space and events defined in (step 1) and the actual production of Baowu carbon materials, the following rule base G and related process parameters are established (this part is only a partial list based on the above five dimensions to serve as an example, and is not a complete list of rules), C is defined as the process scheduling queue, C(B i k) represents crystallization box B i The process arranged in step k: (1) The feed buffer tank is equipped with a minimum liquid level protection ( and ),in, and These respectively represent the minimum liquid level protection provided by the feed buffer tank during feeding and the minimum liquid level protection provided by the feed buffer tank during replenishment; the following standards shall be followed: the minimum liquid level during feeding operation is 5% of the buffer tank capacity, and the minimum liquid level during replenishment operation for heating and melting is 15% of the buffer tank capacity; (2) the feed buffer tank is provided with a maximum liquid level protection (U high (A 10 )~U high (A 18&19 (3) The raw material buffer tank is replenished with raw materials according to the input feeding speed v. The amount of raw material replenished in the raw material buffer tank during the time interval t1 to t2 is V. supple (t1, t2) = (t2 - t1) × v, and must satisfy

[0178] V supple (t1, t2) + V(A) raw ,t)≤U(A raw )-Uhigh (A raw ), where U(A j ) indicates buffer slot A f The capacity; taking buffer tank A13 as an example: Buffer tank A13 is replenished with 95% naphthalene according to the input feed rate. Let the feed rate be v. Then, the amount of material replenished in tank A13 within the time range t1 to t2 is (t2-t1)×v. If V0(t) is used to represent the amount of material replenished in tank A13 at time t, then V0(t) + V(A) must be satisfied. 13 ,t)≤U(A 13 )-U high (A 1a (4)

[0179] For feeding and replenishing, when feeding, the current liquid level in the buffer tank is subtracted from the expected feed amount, and the result of the subtraction is compared with the set low alarm liquid level for feeding in the buffer tank; if it is less than the set low alarm liquid level for feeding in the buffer tank, the subprocess is postponed; otherwise, the liquid level in the buffer tank and the status of the crystallizer are updated.

[0180] When replenishing material, the current liquid level in the buffer tank is subtracted from the replenishment amount, and the result is compared with the set low alarm liquid level for replenishing the buffer tank. If it is lower than the set low alarm liquid level for replenishing the buffer tank, the subprocess is postponed; otherwise, the liquid level in the buffer tank and the status of the crystallizer are updated.

[0181] Here, it is also necessary to combine the regulations of the factory level rules on whether or not it is allowed to operate under full load; if the crystallization box can be filled, then it is operated under full load; if it cannot be filled, under the condition that it is allowed to operate under full load (M>0), all of them are loaded and the filling rate is calculated. The subsequent operations (discharge, sweating, discharge, etc.) are calculated according to the filling rate to calculate the discharge volume; if it is not allowed to operate under full load, then the feeding is postponed. After the feeding is completed, V(b(C(Bi,k)), t) = 0 is updated; (5) Define r(P,h) as the material flow rate of the h-th step operation of the P process, where the feeding or replenishing operation represents the raw material feeding amount, the discharge, sweating, and discharge operation represents the by-product discharge amount, and the melting operation represents the product retention amount. Define t(P,h) as the time of the h-th step operation of the P process (calculated from the start of the P process). Then, for the discharge, sweating, and discharge operations, r(C(B i ,k),h)×V(B i ,t) represents the crystallization chamber B at time t. i For the discharge volume in step h of step k, when step h ends, update the status and level of the buffer tank and crystallizer. Add the discharge volume of the corresponding crystallizer to the level of the buffer tank, and compare the sum with the set high alarm level of the buffer tank. If the sum is greater than the high alarm level of the buffer tank, it means that the remaining liquid level in the buffer tank is insufficient, and this step should be postponed. Otherwise, let r(C(B) = ... i ,k),h)×V(Bi ,t)+V(b(C(B i ,k),h),t)→V(b(C(B) i ,k),h),t), and update the crystallization tank level V(B) i ,t)-r(C(B i ,j),k)×V(B i ,t)→V(B i ,t); (6) process C(B) at time t i After j) ends, if C(B) i ,j+1)=C(B i If (j)+1, it means the next process after the current process is the process following the current process, and no discharge operation is needed. The feeding operation of the subsequent process is changed to a replenishment operation. Otherwise, discharge is required first to b(C(B)+1. i ,j)+1), Update the level and status of the buffer tank and crystallization box V(b(C(Bi,k)+1),t)=V(b(C(Bi,k)+1),t)+V(Bi,t),V(B v t) = 0, and then proceed with the feeding operation; (7) To improve efficiency, try not to execute the P2 process in the crystallizer box 2; (8) According to the scheduler's requirements, the P5 process can only be connected to the P4 process in sequence, and the P4 process can only be connected to the P3 process in sequence. Generally, it is not started alone. Taking the C2 process as an example, its material flow direction, flow rate and operation time are as follows Figure 4 As shown.

[0182] (Step 3) Use an event-triggered model to handle liquid level and status updates: Based on the scheduling rule base G established in step (2), we define the end of each step of each process in each crystallizer and the start of the next operation t(P, h) as an event, triggering the status update of associated objects. That is, the liquid level of the crystallizer and the buffer tank corresponding to the current process, the previous process, or the next process needs to be updated. Each time the status is updated, we need to "pause" the process, i.e., block the process, to complete the update. For example... Figure 13 The "Blocking, State Update" point is shown in the diagram. As scheduling progresses, each crystallizer executes a different process, and the execution time of each process is generally known. Based on this, we can construct a blocking queue. Since the total time of each process step is different, we reconstruct the blocking queue when any crystallizer completes the "melting" operation. For example... Figure 13 The "Regenerate Blocking Queue" point is shown in the image.

[0183] The present invention provides a simulation method for a refined naphthalene crystallization production process. By setting up a blocking queue based on trigger events, a simulation process advancement mode based on the blocking queue is established, and the blocking queue is set in real time. Through this simulation method, the continuous and dynamic characteristics of industrial equipment operation can be achieved, while the generation of tasks, equipment occupation and operation, etc., have temporal uncertainty, thus taking into account both aspects. At the same time, it provides a basic platform for subsequent simulation strategy research and optimization.

Claims

1. A simulation method for a refined naphthalene crystallization production process, characterized in that: The termination of each sub-process or the start of the next sub-process in the production of refined naphthalene crystallization is set as the trigger event. The sub-processes include: seven steps of refined naphthalene production: Concentration II (C2), Concentration I (C1), Purification I (P1), Purification II (P2), Purification III (P3), Purification IV (P4), and Purification V (P5), and multiple sub-processes in each process, such as feeding, crystallization, discharge, sweating, and melting. The simulation process is advanced based on the set trigger events; The process of advancing the simulation based on the set trigger events is specifically as follows: Based on the expected completion time of each sub-process of each process, bottleneck points are established, thus forming a bottleneck point sequence for each process. Establish a blocking queue based on the sequence of blocking points for each process and the execution order between processes; The simulation process is advanced based on the sequence of bottlenecks in each process: The blocking queue is updated according to changes in the set state space, and the blocking queue is set to be updated in real time; The state space is constructed based on defined objects, namely the crystallization box and intermediate buffer tank involved in the production of refined naphthalene crystallization. The state space includes: liquid level in each crystallizer, liquid level in each buffer tank, operating status of each crystallizer, and operating time. When each triggering event is triggered, the state space is determined and updated; The blocking queue is updated based on the determination and update of the state space.

2. The simulation method for a refined naphthalene crystallization production process according to claim 1, characterized in that: The crystallization boxes are configured to have 3 units. in, The first crystallization box is used for the first step of purification process, the first step of concentration process, and the second step of concentration process. The second crystallization box is used for the purification of the second, third, fourth and fifth steps of the process. The third crystallization box is used for the purification of the first step and the purification of the second step. Based on this, a simulation structure was established that features multiple parallel processes and serial processes within each parallel thread.

3. The simulation method for a refined naphthalene crystallization production process according to claim 1, characterized in that: The update of the blocking queue includes: Reconfiguration and update at the end of any process; The corresponding blocking point is deleted and updated when any sub-process ends; Delay update when any sub-process needs to be postponed.

4. The simulation method for a refined naphthalene crystallization production process according to claim 1, characterized in that: When constructing the blocking queue, if the next process is a subsequent process of the previous process, a material replenishment blocking point is constructed; otherwise, a blocking point is constructed in the manner of first discharging and then feeding.

5. The simulation method for a refined naphthalene crystallization production process according to claim 1, characterized in that: The determination of the state space is based on a set scheduling rule base; specifically: When each triggering event is triggered, a determination is made as to whether it conforms to the scheduling rule base. If the conditions are met, the corresponding sub-process is executed; otherwise, the corresponding sub-process is postponed.

6. The simulation method for a refined naphthalene crystallization production process according to claim 5, characterized in that: The scheduling rule base is established based on five dimensions: factory level, crystallizer level, buffer tank level, process level, and process operation sequence level.

7. The simulation method for a refined naphthalene crystallization production process according to claim 6, characterized in that: Whether a rule conforms to the scheduling rule base is determined as follows: First, determine whether a delay is necessary at both the factory level and the crystallization chamber level. If a postponement is necessary due to limitations in the production environment, then it shall be postponed. otherwise, Determine the liquid level in the buffer tank corresponding to the next sub-process, and determine whether it needs to be postponed based on the determination result; If it is feeding or replenishing, the buffer tank is judged to see if the liquid level is insufficient according to the first judgment rule set; if the judgment result is that the liquid level in the buffer tank is insufficient, the sub-process is postponed. If it is a discharge, sweating, or discharge process, the buffer tank is judged to determine whether the liquid level is insufficient according to the second judgment rule. If the judgment result is that the liquid level in the buffer tank is insufficient, the sub-process is postponed.

8. The simulation method for a refined naphthalene crystallization production process according to claim 7, characterized in that: The statement "If it is feeding or replenishing, then the buffer tank is judged to determine whether the liquid level is insufficient according to the set first judgment rule" specifically means: Subtract the current liquid level in the buffer tank from the expected feed rate or the replenishment rate, and compare the result with the set low alarm liquid level in the buffer tank. If it is lower than the set low alarm liquid level in the buffer tank, postpone the subprocess; otherwise, update the liquid level in the buffer tank and the status of the crystallizer.

9. The simulation method for a refined naphthalene crystallization production process according to claim 7, characterized in that: The statement "If it is discharge, sweating, or emission, then the buffer tank is judged to determine whether the liquid level margin is insufficient according to the set second judgment rule" specifically means: Add the discharge volume of the corresponding crystallization box to the liquid level of the buffer tank, and compare the result with the set high alarm liquid level of the buffer tank. If the sum of the values ​​exceeds the high alarm level of the buffer tank, it is determined that the buffer tank level is insufficient and the subprocess is postponed; otherwise, the buffer tank level and the crystallizer status are updated.

10. The simulation method for a refined naphthalene crystallization production process according to claim 6, characterized in that: The aforementioned factory-level rules include whether or not the crystallization chamber is allowed to operate at less than full capacity.

11. The simulation method for a refined naphthalene crystallization production process according to claim 6, characterized in that: The rules at the buffer tank level include the rules for adding raw materials to buffer tanks, as detailed below: The following guidelines should be followed when adding raw materials: 。

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