Digital twinning management system and method for production process of fine chemical nitration technology

Abstract

The invention discloses a digital twinborn management system and method for a fine chemical engineering nitration process production process, the digital twinborn management system simulates a factory production area to establish a 1: 1 three-dimensional digital map, and a chemical plant area scene is visually presented in a platform, including factors such as buildings, roads, pipelines, dynamic equipment, static equipment, instruments and meters, raw materials and the like; the system comprises a signal acquisition module, a data analysis processing module, a valve and pump adjusting module, a safety early warning module and a network management module. According to the method, information such as actual operation conditions, process parameters and equipment states of a real factory is integrated and matched with the virtual digital model, so that real-time tracking, adjustment and optimization in the aspects of factory flow, equipment operation, process parameters, production capacity, quality monitoring and the like are realized, and the flexible production requirements of fine chemical engineering can be better met.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemical production process control, and specifically relates to a digital twin management system and method for a fine chemical nitration process production process. Background Art

[0002] Nitration is a reaction that introduces nitro groups (-NO2) into organic compound molecules. It is used to produce nitro compounds, nitramines, nitrate esters and nitroso compounds. The process involving nitration reaction is called nitration process, which is one of the common reaction types in the field of fine chemicals. Nitration reaction has the characteristics of fast speed, large heat release, and flammability and explosion. The mainstream production method of nitration in China is the intermittent liquid phase nitration method using a mixture of nitric acid and sulfuric acid as a nitrating agent, and the equipment used is a kettle reactor. This process relies on manual feeding and one-time intermittent operation and production, but local heat is easy to accumulate in the kettle, the mass transfer and heat transfer capacity are poor, there are great safety hazards, and safety accidents are prone to occur. The state requires that intermittent and semi-intermittent kettle nitration processes for 27 chemicals such as nitrobenzene be banned and the transformation be completed within two years, prompting a rapid release of technical transformation demand in the next two years.

[0003] In order to improve the safety and reliability of the nitration process, the current mainstream development direction is to carry out continuous transformation, transform the process operation process into a continuous one, and reduce the probability of safety accidents caused by manual misoperation. Compared with intermittent processes, continuous processes are more dependent on a complete automatic control system. If the automatic control system is poorly equipped, the inherent safety of the continuous process cannot be guaranteed. At the same time, the explosion-proof requirements of the nitration process and the flexible production requirements of fine chemicals also put forward higher requirements for the automatic control system.

[0004] At present, DCS systems are mostly used in industry to control the process of production, which is mainly divided into three aspects: detection, operation / command, and execution. Detection includes the arrangement of temperature, pressure, flow, liquid level and other corresponding instruments at each monitoring point. The data signals measured by each instrument are transmitted to the central control room through cables and other channels. By comparing the deviation between the actual measured values ​​and the parameters set by the process requirements, including simple parameters such as temperature, pressure, flow, liquid level, and complex systems such as cascade, ratio, and multiple impulses, a command is issued after the decision is made, and the feedback is sent to the actuators such as control valves to execute the corresponding commands, thereby achieving effective control of the chemical process. Summary of the invention

[0005] In view of this, the present invention provides a digital twin management system and method for the fine chemical nitration process production process, which integrates and matches information such as the actual operation status, process parameters and equipment status of the factory with the virtual digital model to achieve real-time tracking and adjustment optimization of factory processes, equipment operation, process parameters, production capacity and quality monitoring.

[0006] The technical solution for implementing the present invention is as follows:

[0007] A digital twin management system for the production process of fine chemical nitration process, wherein the digital twin management system establishes a 1:1 three-dimensional digital map based on the factory area, and intuitively presents the scene of the chemical plant area on the platform, including buildings, roads, pipelines, dynamic equipment, static equipment, instruments and meters, raw materials and other elements; the digital twin management system includes a signal acquisition module, a data analysis and processing module, a valve and pump regulation module, a safety warning module and a network management module;

[0008] The signal acquisition module includes corresponding instruments such as temperature, pressure, flow, liquid level, and signal transmission devices such as wires and cables. The detected raw data is transmitted to the data analysis and processing module through the signal transmission device;

[0009] The data analysis and processing module includes an original signal database, a predetermined parameter control limit and target value, a data change curve function formed based on empirical data, and an instruction sending device; the original signal database first stores the detection data transmitted by the signal acquisition module, compares the detection data with the predetermined parameter control limit and target value, and when the control limit range is exceeded, an early warning signal or a pop-up window prompt is issued on the integrated platform, and a corresponding instruction is issued to the valve and pump adjustment module through the instruction sending device, so that the parameters return to a reasonable range and gradually remain consistent with the target value;

[0010] The valve and pump regulating module includes an instruction receiving device, an electric regulating valve and a variable frequency pump; after the instruction receiving device of the valve and pump regulating module receives the instruction sent by the sending device of the data analysis and processing module, the corresponding electric regulating valve and variable frequency pump etc. act according to the instruction;

[0011] The safety warning module includes production hazard source monitoring and warning, risk zoning, personnel positioning, and inspection management;

[0012] The network management module includes gateways, 5G base stations, cloud servers, APP terminals, integrated platforms, and encryption channels, identity authentication, error detection and other safe and reliable mechanisms of each key node to monitor and optimize the network status and issue alarms when the network is abnormal.

[0013] Furthermore, a functional relationship between the rate of change of the numerical value and the flow rate is established in the data analysis and processing module, x=f(F,Δx / Δt), where F represents the flow rate, x represents the temperature or pressure, Δx represents the change value of the temperature or pressure within a certain period of time, Δt represents a certain period of time, and Δx / Δt represents the rate of change of the temperature or pressure; when the rate of change of the temperature and pressure is within the limit value range, a single adjustment method is adopted; outside the limit value range, a combined adjustment method is adopted, and the change rate adjustment range of each combined adjustment is calculated, the system adjustment instructions are predicted in advance, and the adjustment action is accurately calculated to reduce the lag effect.

[0014] Furthermore, single regulation means I: x Ⅰ =f1(F Ⅰ ,Δx Ⅰ / Δt), x Ⅰ Indicates the value of temperature or pressure under single means I conditions, Δx Ⅰ It indicates the change of temperature or pressure within a certain period of time under the condition of single means I, Δt indicates a certain time, Δx Ⅰ / Δt represents the rate of change of temperature or pressure under single means I conditions, F Ⅰ It represents the flow value regulated by a single regulating means, and f1 represents the functional relationship of a single regulating means.

[0015] Furthermore, the combination of adjustment means Ⅰ and Ⅱ: x Ⅱ =f2(F Ⅱ ,f1(F Ⅰ ,Δx Ⅱ / Δt)), x Ⅱ Indicates the value of temperature or pressure under the combined conditions of adjustment means Ⅰ and Ⅱ, Δx Ⅱ It indicates the change of temperature or pressure within a certain period of time under the combination of adjustment means Ⅰ and Ⅱ. Δt indicates a certain period of time, Δx Ⅱ / Δt represents the rate of change of temperature or pressure under the combined conditions of adjustment means Ⅰ and Ⅱ, F Ⅰ Indicates the flow value regulated by regulation means Ⅰ, F Ⅱ It represents the flow value regulated by regulating means II, f1 represents the functional relationship under the condition of a single regulating means, and f2 represents the functional relationship under the condition of a combination of regulating means I and II.

[0016] Furthermore, the production hazard monitoring and early warning is to conduct real-time monitoring of hazardous chemical storage facilities, production equipment, flammable and toxic gases, hazardous chemical processes, surveillance videos and other data, and immediately alarm when an abnormal situation occurs. By clicking or searching to locate the alarm point, the alarm status of the equipment can be quickly viewed, and the alarm status can be presented in a prominent form on the equipment model.

[0017] The management method of the digital twin management system comprises the following steps:

[0018] Step 1: The signal acquisition module transmits the collected initial flow value, temperature, pressure, liquid level, flow rate and other signals to the data analysis and processing module;

[0019] Step 2: The data analysis and processing module receives and stores the signal and then processes the signal. It compares and judges the given values ​​of temperature, pressure, liquid level, flow rate, etc. input from the outside. If the warning value is exceeded, an alarm will be sounded and emergency measures will be taken. If the alarm value is not reached, it will continue to judge whether it exceeds the set value; if it is within the set value range, it will continue to monitor the temperature, pressure, liquid level, flow rate and other signals and repeat the above steps.

[0020] If it exceeds the set value range, the valve opening adjustment signal and the variable frequency pump frequency adjustment signal will be calculated and output based on the functional relationship between the externally input valve opening and variable frequency pump frequency and temperature, pressure, liquid level, and flow rate;

[0021] Step 3: The data analysis and processing module sends the adjustment signal to the valve and pump adjustment module to adjust the flow of the equipment, thereby realizing flow adjustment, and further adjusting the temperature, pressure, liquid level and other data until it is adjusted to within the set value, and continuously dynamically monitors and adjusts the key process indicators to ensure normal production.

[0022] Furthermore, the emergency measures, specifically a series of emergency shutdown measures, form an interlocking relationship between the temperature inside the reactor, the pressure inside the reactor, the raw material flow rate, and the cooling circulating water. When the reaction is out of control, an automatic alarm is issued, the feeding is automatically stopped, and the cooling circulating water is fully opened for emergency cooling. At the same time, an explosion relief pipe and an emergency discharge system are provided.

[0023] Beneficial effects:

[0024] 1. The present invention uses a digital twin management system to establish a chemical production information network, improve the automation, digitization and intelligence of chemical process flows and production processes, and can better improve production efficiency, improve product quality, reduce costs, and reduce resource waste and environmental pollution.

[0025] 2. The present invention integrates and matches the actual operation status, process parameters, equipment status and other information of the real factory with the virtual digital model to achieve real-time tracking and adjustment optimization of factory processes, equipment operation, process parameters, production capacity and quality monitoring, which can better meet the flexible production needs of fine chemicals.

[0026] 3. The present invention compares the actual operating status with the digital twin platform in real time, which can detect abnormal situations in time and avoid production accidents and quality problems.

[0027] 4. The safety warning module of the present invention includes production hazard source monitoring and warning, risk zoning, personnel positioning, inspection management, etc. It will immediately alarm when an abnormal situation occurs. By clicking or searching to locate the alarm point, you can quickly check the alarm status of the equipment. You can also link the monitoring video and call out the latest real-time monitoring of the alarm equipment to grasp the real situation on the scene, which is convenient for timely and accurate understanding and handling of emergencies, greatly improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a continuous nitration process and device of this embodiment.

[0029] Figure 2 This is a schematic diagram of the management method of the digital twin management system of this embodiment.

[0030] Figure 3 This is a schematic diagram of the integrated operating platform interface of the digital twin management system of this embodiment.

[0031] Figure 4 This is a signal transmission flow chart of the digital twin management system of this embodiment.

[0032] Among them, R1-first reactor; R2-second reactor; R3-third reactor; R4-fourth reactor; S1-stratification tank; M1-mixed acid feed pump for the first reactor; M2-raw material feed pump for the second reactor; M3-discharge pump for the first reactor; M4-discharge pump for the second reactor; M5-discharge pump for the third reactor; M6-discharge pump for the fourth reactor; M7-waste acid discharge pump; M8-product discharge pump; V1-reaction liquid feed stop valve for the third reactor; V2-second reactor Liquid discharge stop valve; V3-4th reactor circulating reaction liquid discharge stop valve; V4-4th reactor reaction liquid discharge regulating valve; V5-waste acid discharge regulating valve; V6, V7, V8, V9, V10 are all product discharge regulating valves; V11-3rd reactor mixed acid feed stop valve; V12-4th reactor raw material feed stop valve; T1-1st reactor thermometer; T2-2nd reactor thermometer; T3-3rd reactor thermometer; T4-4th reactor thermometer; T5-1st reactor - circulating water channel thermometer for reactor; T6 - circulating water channel thermometer for second reactor; T7 - ​​circulating water channel thermometer for third reactor; T8 - circulating water channel thermometer for fourth reactor; T9 - stratification tank thermometer; P1 - pressure gauge for first reactor; P2 - pressure gauge for second reactor; P3 - pressure gauge for third reactor; P4 - pressure gauge for fourth reactor; P5 - pressure gauge for stratification tank; Y1 - level gauge for stratification tank; F1 - mixed acid feed flowmeter for first reactor; F2 - raw material feed flowmeter for second reactor; F3 - discharge flowmeter for first reactor; F4 - discharge part flowmeter for second reactor; F5 - discharge flowmeter for third reactor; F6 - reaction liquid circulation flowmeter for fourth reactor; F7 - feed flowmeter for stratification tank; F8 - discharge flowmeter for waste acid; F9 - product discharge flowmeter; F10 - circulating water for first reactor; F11 - circulating water for second reactor; F12 - circulating water for third reactor; F13 - circulating water for first reactor; F14 - reaction liquid circulation flowmeter for second reactor. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0034] The present invention provides a digital twin management system for the production process of fine chemical nitration process, the system includes a signal acquisition module, a data analysis and processing module, a valve and pump adjustment module, a safety warning module, a network management module, etc. The system includes a PC terminal and a mobile terminal system to form an integrated platform to realize browsing and control of different terminals.

[0035] The digital twin management system builds a 1:1 three-dimensional digital map based on the factory area, and intuitively presents the scene of the chemical plant area on the platform, including buildings, roads, pipelines, dynamic equipment, static equipment, instruments and meters, raw materials and other elements. It supports the factory roaming function, and can preset different routes for automatic roaming, or manually browse through the mouse, keyboard or mobile terminal touch screen. During the roaming process, information pop-up windows will be displayed on key equipment and facilities, and the operating status information can be understood, so as to achieve the purpose of online inspection.

[0036] The digital twin management system, relying on the continuous nitration reaction process and device, can adjust the production capacity by connecting reactors in parallel and adjust the reaction residence time by connecting reactors in series according to different nitration reaction requirements. It is suitable for a variety of product types and production capacity requirements.

[0037] The signal acquisition module includes corresponding instruments such as temperature, pressure, flow, liquid level, and signal transmission devices such as wires and cables. Considering the danger of nitration reaction, electrical instruments and wires and cables are selected to meet the corresponding explosion-proof level. The raw data detected by the instrument in the signal acquisition module is transmitted to the data analysis and processing module through signal transmission devices such as wires and cables. Since the data analysis module not only requires real-time data of corresponding instruments such as temperature, pressure, flow, liquid level, etc., but also requires the change rate information of corresponding instrument data such as temperature, pressure, flow, liquid level, etc., the data collection time interval is as short as possible.

[0038] The data analysis and processing module includes an original signal database, a predetermined parameter control limit and target value, a data change curve function formed based on empirical data, an instruction sending device, etc. The original signal database first stores the detection data transmitted by the signal acquisition module, and compares the detection data with the predetermined parameter control limit and target value. When the control limit range is exceeded, an early warning signal or a pop-up window prompt is issued on the integrated platform, and a corresponding instruction is issued to the valve and pump adjustment module through the instruction sending device, so that the parameters return to a reasonable range and gradually remain consistent with the target value. The adjustment method can calculate the reasonable adjustment steps based on the data change curve formed by the empirical data, and generate corresponding instructions to transmit to the valve and pump adjustment module. When multiple valves or variable frequency pumps can adjust the same instrument point, the traditional automatic control system usually selects the priority sorting method to adjust in sequence, and because it will only start to act when it is subjected to abnormal signals, the adjustment action will be delayed when the value of the instrument point changes rapidly, which is not conducive to the stability of product quality. Therefore, the present invention also establishes a functional relationship between the rate of change of the value and the flow rate x=f(F,Δx / Δt) (Note: F represents flow rate, x represents temperature or pressure, Δx represents the change value of temperature or pressure within a certain period of time, Δt represents a certain period of time, and Δx / Δt represents the rate of change of temperature or pressure), for example, in the software, simulates and calculates the influence of F1, F5, F10 on T1 and P1, the influence of F2, F3, F11 on T2 and P2, the influence of F4, F6, F12, F14 on T3 and P3, and the influence of F4, F6, F12, F15 on T4 and P4; calculates the limit value of the rate of change of temperature and pressure when the temperature and pressure can be adjusted to the set value under a single adjustment means, such as ΔT1 / Δt (Note: T1 represents the value of T1, and the subsequent T1-T9, P1-P5, F1-F 13 Similarly) is the rate of change of T1 temperature counter value. When T1 just exceeds the set value range, it is necessary to judge whether it can be adjusted within the set value range when only F10 is adjusted under the condition of the change rate of ΔT1 / Δt. The ΔT1 / Δt limit value that can be adjusted within the set value range is used as the basis for judging whether to abandon single adjustment and directly start combined adjustment; and calculate the functional relationship between flow rate, temperature and pressure under the step-by-step combined adjustment means in the order of priority: 1) Single adjustment means I: x Ⅰ =f1(F Ⅰ ,Δx Ⅰ / Δt), (Note: x Ⅰ Indicates the value of temperature or pressure under single means I conditions, Δx Ⅰ It indicates the change of temperature or pressure within a certain period of time under the condition of single means I, Δt indicates a certain time, Δx Ⅰ / Δt represents the rate of change of temperature or pressure under single means I conditions, F Ⅰrepresents the flow value regulated by a single regulating means, and f1 represents the functional relationship of a single regulating means); 2) Combination of regulating means Ⅰ and Ⅱ: x Ⅱ =f2(F Ⅱ ,f1(F Ⅰ ,Δx Ⅱ / Δt)), (Note: x Ⅱ Indicates the value of temperature or pressure under the combined conditions of adjustment means Ⅰ and Ⅱ, Δx Ⅱ It indicates the change of temperature or pressure within a certain period of time under the combination of adjustment means Ⅰ and Ⅱ. Δt indicates a certain period of time, Δx Ⅱ / Δt represents the rate of change of temperature or pressure under the combined conditions of adjustment means Ⅰ and Ⅱ, F Ⅰ Indicates the flow value regulated by regulation means Ⅰ, F Ⅱ represents the flow value regulated by regulating means II, f1 represents the functional relationship under the condition of a single regulating means, and f2 represents the functional relationship under the condition of a combination of regulating means I and II); 3)

[0039] x Ⅲ =f3(F Ⅲ ,f2(F Ⅱ ,f1(F Ⅰ ,Δx Ⅲ / Δt))), (Note: x Ⅲ Indicates the value of temperature or pressure under the combined conditions of adjustment means Ⅰ, Ⅱ and Ⅲ, Δx Ⅲ It indicates the change of temperature or pressure within a certain period of time under the combination of adjustment means Ⅰ, Ⅱ and Ⅲ. Δt indicates a certain period of time, Δx Ⅲ / Δt represents the rate of change of temperature or pressure under the combined conditions of adjustment means Ⅰ, Ⅱ and Ⅲ, F Ⅰ Indicates the flow value regulated by regulation means Ⅰ, F Ⅱ Indicates the flow value regulated by regulation means II, F Ⅲ It represents the flow value regulated by regulating means III, f1 represents the functional relationship under the condition of a single regulating means, f2 represents the functional relationship under the condition of the combination of regulating means I and II, and f3 represents the functional relationship under the condition of the combination of regulating means I, II and III) and so on, and it is used as the basis for the regulating module to adjust the valve opening or the frequency of the variable frequency pump. When the temperature and pressure change rate is within the limit value range, a single regulating means is sufficient; outside the range, the regulating means are gradually combined, and the change rate adjustment range of each combined adjustment is calculated. It can predict in advance which devices in the regulating module need to be mobilized by the system, and accurately calculate the regulating action, reduce the hysteresis effect, reduce the reaction fluctuation, make the product production process more stable, and prevent problems before they happen.

[0040] The valve and pump regulating module includes a command receiving device, an electric regulating valve and a variable frequency pump, etc. After the command receiving device of the valve and pump regulating module receives the command sent by the sending device of the data analysis and processing module, the corresponding electric regulating valve and variable frequency pump, etc., act according to the command.

[0041] The safety warning module includes production hazard monitoring and warning, risk zoning, personnel positioning, inspection management, etc. Production safety hazard monitoring and warning is to monitor the data of hazardous chemical storage facilities, production equipment, combustible and toxic gases, hazardous chemical processes, monitoring videos, etc. in real time, and immediately alarm when an abnormal situation occurs. By clicking or searching to locate the alarm point, you can quickly view the alarm status of the equipment, and present the alarm status on the equipment model in a prominent form, such as continuous red light flashing and high-frequency warning sound. It can also be linked to the monitoring video to call out the latest real-time monitoring of the alarm equipment to understand the real situation on the scene.

[0042] The network management module includes gateways, 5G base stations, cloud servers, APP terminals, integrated platforms, and encryption channels of key nodes, identity authentication, error detection and other safe and reliable mechanisms to monitor and optimize the network status, and can also alarm when the network is abnormal.

[0043] Reference Figure 1 , a continuous nitration process flow and device schematic diagram, the main equipment and instruments include reactor R1-R4, stratification tank S1, pump M1-M8, stop valves V1-V3 and V11-V12, regulating valves V4-V10 and V13-V14, thermometer T1-T9, pressure gauge P1-P5, level meter Y1, flow meter F1-F14.

[0044] Capacity 1 mode: V1 is turned on, V2, V3, V11, V12 are turned off, R1, R2 are connected in series with R3, R4, which is suitable for reactions with long residence time. The nitration process includes the following steps:

[0045] The mixture of sulfuric acid and nitric acid enters the reactor R1 from the bottom of the pipe box through the mixed acid feed pump M1, the raw material enters the reactor R2 from the bottom through the raw material feed pump M2, the reaction liquid flowing out of the top of the reactor R1 enters the reactor R2 from the bottom through the pump M3, and part of the reaction liquid flowing out of the top of the reactor R2 enters the reactor R1 from the bottom through the reaction circulation pump M4, and part of it enters the reactor R3 from the bottom. A certain multiple of the intermediate products with lower temperature are extracted from the outlet of the reactor R2 and returned to the inlet of the reactor R1 for circulation. On the one hand, the cold brought back offsets part of the reaction heat, and at the same time plays a role in diluting the raw materials and preventing violent reactions; on the other hand, the flow rate is increased, the mixing is strengthened, the reaction rate is increased, and the residence time required for the reaction is reduced, thereby reducing the reactor volume. The reaction liquid flowing out of the top of the reactor R2 enters the reactor R3 from the bottom for further maturation, and the reaction liquid flowing out of the top of the reactor R3 enters the reactor R4 through the pump M5 for further maturation until the reaction is completed. After the reaction liquid at the top of the reactor R4 flows out through the pump M6 and enters the stratification tank S1, the waste acid outbound area at the bottom is treated, and the crude product outbound area enters the purification section. The pressure of the four reactors R1-R4 is maintained at 0.6MPaG, and the internal temperature of the reactor is maintained at 35℃ through circulating cooling water in the shell side. The circulating water is transported from the water tank to the heat exchanger tube side through a water pump, and then to the reaction system to transfer heat and return to the water tank through the return water main.

[0046] Capacity 2 mode: V1 is closed, V2, V3, V11, V12 are turned on, R1, R2 and R3, R4 are connected in parallel, which is suitable for reactions with short residence time. The nitration process includes the following steps:

[0047] The mixture of sulfuric acid and nitric acid enters reactor R1 and reactor R3 from the bottom of the pipe box through the mixed acid feed pump M1, and the raw materials enter reactor R2 and reactor R4 from the bottom through the raw material feed pump M2. The reaction liquid flowing out of the top of reactor R1 enters reactor R2 from the bottom through pump M3, and part of the reaction liquid flowing out of the top of reactor R2 enters reactor R1 from the bottom through reaction circulation pump M4, and part enters stratification tank S1. A certain multiple of the intermediate products with lower temperature are extracted from the outlet of reactor R2 and returned to the inlet of reactor R1 for circulation. On the one hand, the cold brought back offsets part of the reaction heat, and at the same time plays a role in diluting the raw materials and preventing violent reactions; on the other hand, the flow rate is increased, the mixing is strengthened, the reaction rate is increased, and the residence time required for the reaction is reduced, thereby reducing the reactor volume. The reaction liquid flowing out of the top of reactor R3 enters reactor R4 from the bottom through pump M5, and part of the reaction liquid flowing out of the top of reactor R4 enters reactor R3 from the bottom through reaction circulation pump M6, and part enters stratification tank S1. A certain multiple of the intermediate product with lower temperature is extracted from the outlet of reactor R4 and returned to the inlet of reactor R3 for circulation. On the one hand, the cold brought back offsets part of the reaction heat and dilutes the raw materials to prevent violent reactions. On the other hand, it increases the flow rate, strengthens mixing, increases the reaction rate, and reduces the residence time required for the reaction, thereby reducing the reactor volume. After entering the stratification tank S1, the reaction liquid is treated in the waste acid outbound area at the bottom, and the crude product outbound area enters the purification section. The pressure of the four reactors R1-R4 is maintained at 0.6MPaG. The reactor maintains the internal temperature at 40°C through the circulating cooling water of the shell side. The circulating water is transported from the water tank to the heat exchanger tube side through a water pump, and then to the reaction system to remove heat and return to the water tank through the return water main.

[0048] Reference Figure 2 , a schematic diagram of the management method of the digital twin management system, including a signal acquisition module, a data analysis and processing module, a valve and pump adjustment module, a safety warning module, etc. The initial flow value, temperature, pressure, liquid level, flow rate and other signals are transmitted to the data analysis and processing module, and the signals are received and stored for data processing. The given values ​​of temperature, pressure, liquid level, flow rate and other given values ​​input from the outside are compared and judged. If the warning value is exceeded, an alarm will be issued and emergency measures will be taken. If the alarm value is not reached, it will continue to judge whether it exceeds the set value. If it is within the set value range, the temperature, pressure, liquid level, flow rate and other signals will continue to be monitored, and the above steps will be repeated; if it exceeds the set value range, the valve opening adjustment signal and the variable frequency pump frequency adjustment signal will be calculated and output according to the functional relationship between the valve opening and the variable frequency pump frequency input from the outside and the temperature, pressure, liquid level and flow rate, so as to realize the flow adjustment, and further realize the adjustment of the temperature, pressure, liquid level and other data until it is adjusted to within the set value, and the dynamic monitoring and adjustment of the key process indicators will be continuously carried out to ensure normal production.

[0049] Reference Figure 3, a schematic diagram of the integrated operation platform interface of the digital twin management method and system, the interface includes the display of real-time values, set values, and alarm values ​​of each monitoring point such as temperature, pressure, liquid level, and flow, as well as the real-time value display of valve status and variable frequency pump frequency. The mode can be switched to manual or automatic. In manual mode, the valve status and variable frequency pump frequency can be set manually; in automatic mode, the valve status and variable frequency pump frequency are automatically adjusted by the system. The platform interface also prominently displays the production capacity, which is convenient for distinguishing whether the current reactor is in series or parallel state, and the corresponding points and set values ​​are also adjusted accordingly.

[0050] Reference Figure 4 , the signal transmission process is shown in the figure. The signals of the temperature, pressure, liquid level, flow and other detection points are directly transmitted to the central control and gateway through cables. The gateway transmits the signal to the base station, and the base station sends the signal to the cloud server for easy access by mobile terminals. The central control and terminals can access the integrated platform through the cloud server and realize process adjustment through data analysis. To ensure the confidentiality of data, each terminal needs to go through an encrypted channel and pass identity authentication to access the cloud server. At the same time, in order to ensure the stability of communication, signal error detection will be performed regularly to avoid communication affected by poor network status, thereby causing misjudgment.

[0051] Embodiment 1:

[0052] based on Figure 1 The nitrification process in the unit capacity 1 mode includes the following steps:

[0053] S1, a mixed acid solution (a mixture of 98% concentrated nitric acid and 98% concentrated sulfuric acid in a mass ratio of 1:3) with a flow rate of 120kg / h enters the reactor R1 from the bottom of the pipe box through the mixed acid feed pump M1, and the raw material 2,5-dichloro-(1,1,2,3,3,3-hexafluoropropoxy)benzene with a flow rate of 120kg / h enters the reactor R2 from the bottom through the raw material feed pump M2, and the reaction liquid flowing out of the top of the reactor R1 enters the reactor R2 from the bottom through the pump M3, and part of the reaction liquid flowing out of the top of the reactor R2 enters the reactor R1 from the bottom through the reaction circulation pump M4, and part of it enters the reactor R3 from the bottom. A certain multiple of the intermediate products with lower temperature are extracted from the outlet of the reactor R2 and returned to the inlet of the reactor R1 for circulation. On the one hand, the cold brought back offsets part of the reaction heat, and at the same time plays a role in diluting the raw materials and preventing violent reactions; on the other hand, the flow rate is increased, the mixing is strengthened, the reaction rate is improved, and the residence time required for the reaction is reduced, thereby reducing the reactor volume.

[0054] S2, the reaction liquid flowing out of the top of reactor R2 enters reactor R3 from the bottom for further maturation, and the reaction liquid flowing out of the top of reactor R3 enters reactor R4 through pump M5 for further maturation until the reaction is completed.

[0055] The reaction liquid with a flow rate of 240 kg / h at the top of S3 and reactor R4 flows out through pump M6 and enters the stratification tank S1. The composition of the reaction liquid is shown in Table 1. The waste acid with a flow rate of 103 kg / h at the bottom of S1 is treated in the outbound area, and the crude nitration product 1,4-dichloro-2-(1,1,2,3,3,3-hexafluoropropoxy)-5-nitrobenzene with a flow rate of 137 kg / h enters the purification section.

[0056] S4. The pressure of the four reactors R1-R4 is maintained at 0.6MPaG. The reactor maintains the internal reaction temperature at 35℃ through the circulating cooling water in the shell side. 1500kg / h of desalinated circulating water is used as the cooling medium and is transported from the water tank to the heat exchanger tube side through a water pump, and then to the reaction system to transfer heat and return to the water tank through the return water main.

[0057] Table 1

[0058]

[0059] Table 2

[0060]

[0061] Embodiment 2:

[0062] Based on the case of Example 1, a production abnormality handling scenario is provided. Specifically, the temperature counter value of the R1 reactor is 38° C. The abnormality handling steps are as follows:

[0063] The real-time value of S1 and T1 signals is 38℃. The signal is transmitted to the data analysis and processing module. The data is first received and stored, and then enters the data processing program. The T1 data is compared with the given high temperature alarm value of 45℃. It does not exceed the alarm value, so no alarm is temporarily given and no emergency measures are taken. No alarm is displayed in the integrated platform, and the automatic control program is executed first.

[0064] The S2 and T1 data are then compared with the given set value of 35°C. There is a large deviation from the set value of 35°C. At this time, the system calculates the cooling circulating water F10 flow rate, the mixed acid feed flow rate F1 and the circulating reaction liquid flow rate F5 that can affect T1. Based on the functional relationship, the V7 valve opening, V13 valve opening and M1 frequency that control the above flow rates are optimized and calculated, and adjusted according to the set coordinated adjustment priority order, and the adjustment signal is sent to the corresponding valve and variable frequency pump to achieve flow adjustment.

[0065] S3. Collect T1 data again and find that the data gradually returns to the set value and stabilizes at the set value.

[0066] S4. During the adjustment process, the system also performs real-time analysis on the rate of change of temperature and pressure. When the rate of change is in the range where the target value can be restored by adjusting the cooling circulating water F10 flow rate alone, only F10 can be adjusted; when the rate of change exceeds the above range, the cooling circulating water F10 flow rate and the mixed acid feed flow rate F1 are combined at the same time; and so on, the combinations are made step by step in order of priority, and finally the circulating water F10 flow rate, the mixed acid feed flow rate F1 and the circulating reaction liquid flow rate F5 are combined.

[0067] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A digital twin management system for the production process of fine chemical nitration process, characterized in that: It includes signal acquisition module, data analysis and processing module, valve and pump regulation module, safety warning module and network management module; The signal acquisition module includes various instruments and cable signal transmission devices, and the detected raw data is transmitted to the data analysis and processing module through the signal transmission device; The data analysis and processing module includes an original signal database, preset parameter control limits and target values, a data change curve function formed based on empirical data, and an instruction sending device; the original signal database stores the detection data sent by the signal acquisition module, compares the detection data with the parameter control limits and target values, and issues an early warning signal or a pop-up window prompt when the control limit range is exceeded, and issues corresponding instructions to the valve and pump adjustment module through the instruction sending device, so that the parameters return to a reasonable range and remain consistent with the target value; The valve and pump regulating module includes an instruction receiving device, an electric regulating valve and a variable frequency pump; after the instruction receiving device receives the instruction sent by the data analysis and processing module, the electric regulating valve and the variable frequency pump act according to the instruction; The safety early warning module includes production hazard source monitoring and early warning, risk zoning, personnel positioning, and inspection management; The network management module is used to monitor and optimize the network status and issue an alarm when the network is abnormal.

2. The digital twin management system according to claim 1, characterized in that: In the data analysis and processing module, a functional relationship between the rate of change of the numerical value and the flow rate is established, x=f(F,Δx / Δt), where F represents the flow rate, x represents the temperature or pressure, Δx represents the change value of the temperature or pressure within a certain period of time, Δt represents a certain period of time, and Δx / Δt represents the rate of change of the temperature or pressure; when the rate of change of the temperature and pressure is within the limit value range, a single adjustment method is adopted; outside the limit value range, a combined adjustment method is adopted, and the change rate adjustment range of each combined adjustment is calculated, the adjustment instructions of the system are predicted in advance, and the adjustment action is accurately calculated to reduce the lag effect.

3. The digital twin management system according to claim 2, characterized in that: Single adjustment means Ⅰ: x Ⅰ =f1(F Ⅰ ,Δx Ⅰ / Δt), x Ⅰ Indicates the value of temperature or pressure under single means I conditions, Δx Ⅰ It indicates the change of temperature or pressure within a certain period of time under the condition of single means I, Δt indicates a certain time, Δx Ⅰ / Δt represents the rate of change of temperature or pressure under single means I conditions, F Ⅰ It represents the flow value regulated by a single regulating means, and f1 represents the functional relationship of a single regulating means.

4. The digital twin management system according to claim 2, characterized in that: Combination of combined regulation means Ⅰ and Ⅱ: x Ⅱ =f2(F Ⅱ ,f1(F Ⅰ ,Δx Ⅱ / Δt)), x Ⅱ Indicates the value of temperature or pressure under the combined conditions of adjustment means Ⅰ and Ⅱ, Δx Ⅱ It indicates the change of temperature or pressure within a certain period of time under the combination of adjustment means Ⅰ and Ⅱ. Δt indicates a certain period of time, Δx Ⅱ / Δt represents the rate of change of temperature or pressure under the combined conditions of adjustment means Ⅰ and Ⅱ, F Ⅰ Indicates the flow value regulated by regulation means Ⅰ, F Ⅱ It represents the flow value regulated by regulating means II, f1 represents the functional relationship under the condition of a single regulating means, and f2 represents the functional relationship under the condition of a combination of regulating means I and II.

5. The digital twin management system according to claim 1, characterized in that: The production hazard source monitoring and early warning is to conduct real-time monitoring of hazardous chemical storage facilities, production equipment, flammable and toxic gases, hazardous chemical processes, surveillance videos and other data, and immediately alarm when an abnormal situation occurs. By clicking or searching to locate the alarm point, the alarm status of the equipment can be quickly viewed, and the alarm status will be presented in a prominent form on the equipment model.

6. A management method applied to any system of claims 1 to 5, characterized in that: The following steps are involved: Step 1: The signal acquisition module transmits the collected initial flow value, temperature, pressure, liquid level, flow rate and other signals to the data analysis and processing module; Step 2: The data analysis and processing module receives and stores the signal and then processes the signal. It compares and judges the given values ​​of temperature, pressure, liquid level, flow rate, etc. input from the outside. If the warning value is exceeded, an alarm will be sounded and emergency measures will be taken. If the alarm value is not reached, it will continue to judge whether it exceeds the set value; if it is within the set value range, it will continue to monitor the temperature, pressure, liquid level, flow rate and other signals and repeat the above steps. If it exceeds the set value range, the valve opening adjustment signal and the variable frequency pump frequency adjustment signal will be calculated and output based on the functional relationship between the externally input valve opening and variable frequency pump frequency and temperature, pressure, liquid level, and flow rate; Step 3: The data analysis and processing module sends the adjustment signal to the valve and pump adjustment module to adjust the flow of the equipment, thereby realizing flow adjustment, and further adjusting the temperature, pressure, liquid level and other data until it is adjusted to within the set value, and continuously dynamically monitors and adjusts the key process indicators to ensure normal production.

7. The management method according to claim 6, characterized in that: The emergency measures are specifically a series of emergency shutdown measures, which form an interlocking relationship between the temperature inside the reactor, the pressure inside the reactor, the raw material flow rate, and the cooling circulating water. When the reaction is out of control, an automatic alarm is issued, the feeding is automatically stopped, and the cooling circulating water is fully opened for emergency cooling. At the same time, an explosion relief pipe and an emergency discharge system are provided.

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