Continuous control system of intermittent polypropylene device

Abstract

The invention relates to the technical field of batch-type liquid phase bulk polymerization processes, in particular to a continuous control system of a batch-type polypropylene device. Comprising a signal control module, a CPU module and a signal processing unit which are installed in an SDT-4000 system, a numerical control instrument and a process operation module which are connected to process equipment, and an acquisition control module which is connected with the process operation module and the numerical control instrument. The signal control module is connected with the CPU module, the CPU module is connected with the signal processing unit, and the signal processing unit is connected with the acquisition control module. According to the continuous control system for the intermittent polypropylene device, automatic operation of the whole process flow is achieved through the CPU unit, the CPU module and the signal processing unit are installed in the SDT-4000 system, all parts in the system are relatively independent, the stability of the system is guaranteed, the polymerization kettle and the flash evaporation kettle are each provided with a set of control system, and the stability of the system is improved. The two parts are mutually independent, and when one device breaks down, work of the other device is not affected.

Description

Technical Field

[0001] The invention relates to the technical field of intermittent liquid phase bulk polymerization technology, in particular to a continuous control system of an intermittent polypropylene device. Background Art

[0002] The intermittent liquid phase bulk polymerization process is a unique polypropylene production process technology independently developed by my country in the 1970s. Due to the limitation of the technology development period, the original technology itself has many shortcomings, such as: high labor intensity of operators, many human factors, unstable product quality, and irregular production operations. In the operation process, there are many steps that need to be operated manually, and it is easy to make mistakes and cause accidents. Especially in the process of manual dosing, there will be combustible gas emissions and even activators will penetrate the venting system to cause smoke and fire accidents. The quality and sense of responsibility of the operators are high and the danger is great. In the prior art, with the development of technology, hydrogenation, feeding, three doses and heating and temperature rise, cold water boost, constant temperature and pressure and high-pressure recovery operations can be automatically controlled in sections in production, but each step requires manual complex operations, and the steps are still cumbersome. At the same time, the existing operating system calculates and controls each step in the same CPU. When the CPU fails, it is easy to cause serious system failures, and there are safety hazards. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the deficiencies of the prior art, the present invention provides a continuous control system for an intermittent polypropylene device, which solves the problems of incoherent automatic control, high dependence on personnel, and high potential safety hazards of the system.

[0004] (II) Technical solution In order to solve the above problems, the present invention provides a batch polypropylene device continuity control system, comprising: a signal control module, a control mechanism and a process device, each process device is provided with a separate control mechanism, a process device and a control mechanism are combined into a control group, and the control system includes a plurality of control groups; The control mechanism includes: a CPU module, a signal processing unit, an acquisition control module and a process operation module; a control signal is input through the signal control module and sent to the CPU module of the corresponding control group, the CPU module performs calculations based on the received control signal and sends the result to the signal processing unit, the signal processing unit sends the received signal to the acquisition control module, the acquisition control module transmits the signal to the process operation module, the process operation module is installed on the process equipment and is divided into several process units according to different process operations, and the process equipment is adjusted according to the received signal; the CPU module and the signal processing unit are installed in the SDT-4000 system controller; a number of numerical control instruments are arranged on the process equipment, and the numerical control instruments are connected to the acquisition control module to transmit the state parameters in the process equipment to the acquisition control module.

[0005] Preferably, the signal control module is controlled simultaneously by two control networks A and B, and the two networks A and B are independent of each other.

[0006] Preferably, the process equipment is a polymerization reactor or a flash reactor.

[0007] Preferably, the outlet of the polymerization kettle is connected to the flash kettle via a feed pipeline, and an electric discharge door and an electric feed door are sequentially provided on the feed pipeline.

[0008] Preferably, the loading electric door and the unloading electric door are respectively controlled by two independent AND logics, and the two signal sources of each AND logic are respectively from the collection control module corresponding to the flash kettle and the collection control module corresponding to the polymerization kettle.

[0009] Preferably, the process units in the process operation module are independent of each other.

[0010] Preferably, the CPU module includes a plurality of mutually independent CPU units, and each process unit in the process operation module corresponds to an independent CPU unit in the CPU module.

[0011] Preferably, the numerical control instrument continuously monitors the production parameters in the process equipment in real time and transmits the transmitted signals to the CPU module.

[0012] (III) Beneficial effects The intermittent polypropylene device continuity control system provided by the present invention is provided with a process operation module installed on the process equipment and a corresponding CPU unit for each process unit to realize the automatic operation of the whole process of the process flow, thereby improving the automation level of the system, reducing the dependence of the system operation on the quality of personnel, and reducing the accident rate. At the same time, the various parts are independent of each other, and the failure of one unit will not affect the normal operation and adjustment of other parts; by installing the CPU module and the signal processing unit in the SDT-4000 system, the various parts in the system are relatively independently controlled, and there is sufficient system redundancy to ensure the stability of the system; by respectively providing a set of control systems for the polymerization kettle and the flash kettle, the two parts are independent of each other, when one device fails, the operation of the other device is not affected, the stability of the device is improved, and the failure rate is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural diagram of the continuity control system of the intermittent polypropylene device of the present invention; Figure 2 The present invention is a flow chart of the intermittent polypropylene device continuity control system.

[0014] Among them, 1. signal control module; 2. CPU module; 3. signal processing unit; 4. acquisition control module; 5. polymerization kettle; 6. flash kettle; 7. unloading door; 8. loading door. Implementation

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by “upper”, “lower”, “inside”, “outside”, “top”, “bottom”, etc. are all based on the orientations or positional relationships shown in the accompanying drawings. The purpose is only to facilitate the description of the present invention and simplify the description. It does not indicate or imply that the referred parts must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Embodiment 1:

[0017] like Figure 1-2 As shown, the present invention provides a continuous control system for an intermittent polypropylene device, specifically comprising: a signal control module 1, a control mechanism and process equipment, each process equipment cooperates with a set of control mechanisms to form a control group, and each system of the present invention includes several control groups; The control system includes: a CPU module 2, a signal processing unit 3, an acquisition control module 4 and a process operation module; During the working process, the operation of the device is controlled by inputting preset working parameters and start and stop signals into the signal control module 1. The signal control module 1 is connected to several control mechanisms at the same time, and is connected to the CPU module 2 in each control mechanism. The signal control module 1 transmits the input preset working parameters and start and stop signals to the CPU module 2 for processing; the CPU module 2 is connected to the signal processing unit 3, and the result processed by the CPU module 2 is sent to the signal processing unit 3, and the signal processing unit 3 integrates the data and transmits it to the next module; the signal processing unit 3 is connected to the acquisition control module 4, and the signal processing unit 3 transmits the received calculation result signal to the corresponding part of the acquisition control module 4; the acquisition control module 4 is connected to the process operation module, and the process operation module is installed on the process equipment. After the acquisition control module 4 transmits the signal to the process operation module, the process operation module adjusts the process according to the received signal.

[0018] The signal control module 1 is connected to each control group through two control networks A and B. The two control networks control the system at the same time. When one of the networks fails, the other network can continue to work normally, ensuring the normal operation of the system and improving the stability of the system. In this embodiment, the two control networks A and B of the signal control module are formed by parallel A switches and B switches, and several parallel operation stations are used to input control signals. At the same time, each operation station is connected to the A switch and the B switch at the same time.

[0019] Furthermore, the A control network and the B control network are connected to the CPU module 2 in the control group. The signal input by the signal control module 1 is input into the CPU module 2 through the A and B operation networks. The CPU module 2 processes the signals input by the two control networks before performing calculations to prevent the signals of the two control networks from acting at the same time and causing repeated operations, thereby improving the accuracy of the system.

[0020] The CPU module 2 and the signal processing unit 3 are installed in a controller with the SDT-4000 system as the framework. According to the characteristics of the SDT-4000 system, 1:1 redundancy can be provided for the CPU module 2. When the CPU fails during operation, the redundant CPU can be switched to for calculation and control without affecting the normal operation of the device. At the same time, the system has sufficient time to wait for the staff to repair and restore the faulty CPU, thereby reducing the system failure rate, improving the system maintenance efficiency and work efficiency, and improving the stability of the system.

[0021] The CPU module 2 includes several CPU units, each of which independently processes the calculation and data processing corresponding to different process operations, and then uniformly transmits the calculated data to the signal processing unit 3. The information processing of each process is relatively independent, which can reduce the CPU load, reduce the occurrence of CPU overload accidents, and improve the stability of the device. At the same time, when a CPU unit fails, the CPU units corresponding to the remaining processes can still work normally and make adaptive adjustments to the impact of the failure in time to ensure the stability and safety of the environment inside the process equipment and improve the safety of the system.

[0022] In the present invention, the signal processing unit 3 is connected to the CPU module and the acquisition control module 4. After the calculation is completed, each unit in the CPU module 2 sends the calculation result and the signal to the signal processing unit 3. The signal processing unit 3 integrates all the received signals and then sends the integrated signal to the acquisition control module 4. The acquisition control module 4 is connected to the process operation module, which is installed on the process equipment. The process equipment is adjusted in production according to the received signal so that the production parameters during production reach the set value of the signal control module 1.

[0023] Among them, the process control module includes a hydrogenation unit, a feeding unit, a three-dose feeding unit, a hot water control unit, a cold water control unit and a reaction automatic control unit, etc. The units are independent of each other. When one of the units fails, the other units can still work freely, and targeted accident handling adjustments can be made to the process equipment under failure, providing protection for the production safety of the system.

[0024] Furthermore, each unit in the process control module is responsible for adjusting the corresponding process. Each process unit in the process control module in the CPU module 2 has a corresponding CPU unit, so that each process can be independently operated and controlled, and will not affect each other when a failure occurs, thereby improving the stability of the system.

[0025] The process equipment is provided with a number of numerical control instruments, which are connected to the acquisition control module 4. During the operation of the device, the numerical control instruments continuously collect and transmit various real-time data of the device to the acquisition control module 4, and then the acquisition control module 4 continues to pass the collected real-time data upward to the signal processing unit 3 and the CPU module 2 in sequence. After the CPU module 2 performs simple processing on the data, the data is transmitted to the signal control module 1 for display to the operator. At the same time, during the production process, if the target process parameters have been set and the data transmitted back does not match the set values, the CPU module 2 will calculate the process and adjustment that need to be adjusted based on the difference between the two, and then transmit the adjustment signal downward again.

[0026] The data transmitted by the digital control instrument include kettle temperature, kettle pressure, kettle current, cold water flow, hot water flow and additive flow.

[0027] In the present invention, the process equipment includes a polymerization kettle 5 and a flash kettle 6, which are independent of each other and are respectively equipped with a set of control systems. The production product of the polymerization kettle 5 is the production raw material of the flash kettle 6, and the two are independent of each other. In the traditional intermittent propylene device, the two are controlled by a centralized CPU unit. Once an accident occurs in the CPU unit, all polymerization kettles 5 or flash kettles 6 need to be processed at the same time. If the processing is not timely, serious consequences will occur. The connection control method in the present invention allows the device to be operated. When the CPU unit fails, it will only affect the corresponding polymerization kettle 5 or flash kettle 6. The staff only needs to repair and process the affected equipment, reducing the workload of the staff and reducing safety hazards.

[0028] Each polymerization kettle 5 corresponds to a flash kettle 6, and the two are connected by a feed pipeline. During normal operation, the reaction product in the polymerization kettle 5 enters the flash kettle 6 through the feed pipeline and is further processed as a production raw material.

[0029] It should be noted that the feed pipeline is provided with a loading electric door 8 and a unloading electric door 7, which are respectively controlled by an independent AND logic. The two signal sources of each AND logic come from the collection control module 4 corresponding to the flash kettle 6 and the collection control module 4 corresponding to the polymerization kettle 5. When one of the process equipment fails, its corresponding collection control module 4 sends a closing signal to the feed pipeline. At this time, the loading electric door (8) and the unloading electric door (7) are closed at the same time to isolate the two, thereby ensuring that the raw materials in the process equipment in normal operation are not contaminated, thereby improving the working efficiency and safety of the system.

[0030] In the present invention, the one process equipment and one control system are combined into one control group. The intermittent polypropylene device continuity control system of the present invention is composed of several control groups. Embodiment 2:

[0031] Taking the device startup process as an example, the working principle of the intermittent polypropylene device continuity control system of the present invention is explained.

[0032] First, set the initial parameters and send a start signal. Input the predetermined process parameters to the system through the workstation and send a start signal. Each unit in the CPU module sends a control signal according to the pre-set program. The signal is transmitted step by step to the process operation module, and the device starts to start. At the same time, the CNC instrument transmits the detected data to the CPU module step by step as feedback for adjustment, and sends the signal to the signal control module.

[0033] Among them, the initial parameters that need to be set include: the setting value of the cold and hot water switching pressure when the polymerization kettle is heated, the constant temperature setting value, the recovery end pressure setting value after the reaction is completed, the return water switching temperature at the jacket outlet of the polymerization kettle, the stirring current setting value at the polymerization reaction end point, the automatic hydrogenation amount setting value, the propylene feed bottom material addition amount setting value (first stage setting value), the propylene input amount setting value when the activator is added (second stage setting value), the propylene input amount setting value when the third component is added (third stage setting value) and the total propylene amount setting value.

[0034] Then, the hydrogenation start signal is sent through the signal control module. Before the hydrogenation start signal is issued, it is necessary to first determine whether the "hydrogenation set value" is correct, and then determine whether the pressure of the polymerization kettle allows hydrogenation operation, whether the hydrogen pressure is greater than 1.2MPa, and whether the valve of the hydrogenation system is in the automatic position; after everything is normal, the hydrogenation signal is calculated by the CPU module and transmitted to the process control module step by step, and the hydrogenation valve on the polymerization kettle is controlled to open, the outlet switch valve of the hydrogenation system is opened, and the outlet regulating valve of the hydrogenation system begins to adjust in turn. During the control process, the flow rate is kept within the range of 2-6kg / h and the pressure is kept within the range of 1.2-2.0MPa. At this time, the "hydrogenation batch accumulation" begins to accumulate; when the feedback "hydrogenation batch accumulation" reaches the "hydrogenation set value", the CPU module determines that the hydrogenation is over, and each CPU unit sends a control signal to the process control module step by step, closes the hydrogenation system switch valve, and then closes the hydrogen valve above the polymerization kettle to end the hydrogenation process.

[0035] Among them, the "hydrogenation" start button is interlocked with the closed status of the upper and lower spray valves of the polymerization kettle, the upper and lower valves of the catalyst pipeline for feeding, and the activator pipeline valve. If any valve is not closed in place, the "hydrogenation" button will be gray and cannot be clicked to start, that is, the hydrogenation start signal cannot be sent.

[0036] Secondly, the feed start signal is sent through the signal control module. Before sending the feed start signal, it is necessary to first determine whether the "hydrogenation set value" is correct, and then determine the propylene pump start status, The propylene feed valve and reflux valve are in automatic state, the valves of the polymerization kettle are all in closed and automatic state (because feeding is the starting signal of the polymerization kettle control), the set value of the propylene bottom material, the set value of the cumulative amount of propylene for the activator, the set value of the cumulative amount of propylene for the third component, and the set value of the total amount of propylene are correct, the liquid level of the activator metering tube and the liquid level of the three-component metering tube are normal, whether the catalyst has been added to the hopper, and whether the three-dose control system are all in automatic state. After everything is normal, the feed signal is calculated by the CPU module and then transmitted to the process control module step by step, which controls the opening of the activator valve above the polymerization kettle, the opening of the regulating valve of the feed system, and the closing of the reflux valve (if the propylene pressure is too high, it will automatically adjust to a certain opening). At this time, the "propylene batch accumulation" begins to accumulate. During the control process, the CNC instrument transmits the detected data to the CPU module step by step. Each unit in the CPU module calculates according to the feedback value and transmits the adjustment signal to the process control module step by step to keep the flow and pressure within the set value range. During the entire feeding process, the propylene pressure should be greater than 1.2MPa in winter and greater than 1.5MPa in summer; if the propylene pressure is too high (1.9MPa), the CPU module sends a control signal based on feedback to control the reflux valve to release the pressure.

[0037] The “Feed” start button is interlocked with the closed status of the upper and lower spray valves of the polymerization kettle and the hydrogenation valve on the polymerization kettle. If any valve is not closed properly, the “Feed” button will be gray and cannot be clicked to start, that is, the feed start signal cannot be sent.

[0038] Again, the heating start signal is sent through the signal control module. Before sending the heating start signal, it is necessary to make sure that the temperature of the hot water tank has reached the heating requirement (80℃ or above in winter and 70℃ or above in summer); the hot water pump has been started; the return valve at the outlet of the polymerization kettle jacket is in automatic state; the hot water, cold water and recovery regulating valves of the polymerization kettle are in automatic state; and the other valves of the polymerization kettle are in the closed position. After the hot water regulating valve is opened, the inlet temperature of the polymerization kettle jacket begins to rise, and the CPU module continuously receives the operating parameters transmitted by the CNC instrument. When the outlet temperature of the jacket reaches the "return water switching temperature setting value" (generally set between 45-50℃), the CPU module sends a control signal to control the jacket outlet cold water valve to close and the hot water valve to open. When the pressure of the polymerization kettle rises to the "cold and hot water switching setting value", the CPU module sends a control signal to control the closing of the hot water valve and the opening of the hot water tank return valve (if there is no other polymerization kettle in the heating stage) to end the heating process. At this time, the CPU module sends a signal again to control the jacket cold water regulating valve to open, and control the polymerization reaction to enter the temperature rise and constant temperature stage.

[0039] When the hot water regulating valve is closed and the cold water regulating valve is opened, the control system controls the heating speed through cold water. At this time, the CPU module calculates and judges the initial constant temperature process based on the feedback of heating speed, cold water flow, reaction time and other factors. The CPU module automatically sends a signal to control the end of the initial constant temperature and continue to heat up to the "constant temperature set value" based on the reaction parameters of the polymerization kettle.

[0040] Among them, a secondary overpressure protection program is set in the SDT-4000 system where the CPU module and the signal processing unit are located. If the polymerization kettle is overpressured, the CPU module determines based on the feedback signal that the high-pressure recovery valve is in manual state. When the pressure of the polymerization kettle reaches the secondary alarm value, the CPU module automatically sends a control signal to control the high-pressure recovery valve to open and release pressure to protect production safety.

[0041] Finally, the recovery start operation is performed. When the production status meets the preset production status, the CPU module automatically controls the recovery valve to open gradually. When the parameter change obtained by feedback matches the set value, the recovery valve is controlled to stop and maintain the opening until all the liquid propylene evaporates. The recovery valve continues to be opened to speed up the recovery speed. When the pressure of the polymerization kettle is lower than the "recovery end pressure value", the recovery process ends, and the interlock protection for the injection is released. The operator of the polymerization post can directly authorize the operator of the flash steam post and supply power to the injection operation, allowing the operator of the flash steam post to perform the injection operation. The polymerization kettle enters the "injection allowed" state, authorizes the flash steam injection operation, supplies power (operator operation required) and waits for injection. At this point, the "one-button start" polymerization process is completely over.

[0042] During the recovery start-up operation, the operator can, based on his own experience, start the recovery process in advance by sending a recovery start signal through the "recovery" start button when the constant temperature control program has not determined the conditions for ending the polymerization reaction.

[0043] The intermittent polypropylene device continuity control system provided by the present invention can realize full automation of the process flow, improve system stability, and reduce the system accident rate. The specific working process of the system is as follows: Step 1: input the start process parameters and the start signal through the signal control module 1, and the signal control module 1 transmits the process parameters and the signal and the start signal to the CPU module 2; Step 2, the CPU module 2 calculates the process unit that should be adjusted according to the received signal, and the CPU unit corresponding to the process unit performs the calculation and sends the calculation result to the signal processing unit 3; Step 3: The signal processing unit 3 integrates the received signal and sends it to the acquisition control module 4, and the acquisition control module 4 sends the signal to each corresponding unit in the process operation module; Step 4: Each unit of the process operation module operates the process equipment to make adjustments according to the received signal; Step 5: The numerical control instrument in the process equipment feeds back various parameters in the equipment to the CPU module 2 in real time through the acquisition module and the signal processing unit 3; Step 6. Repeat steps 2 to 5 until the feedback signal is the same as the input setting value.

[0044] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. 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 batch polypropylene device continuity control system, characterized in that: include: A signal control module (1), a control mechanism and a process device, each process device is provided with a separate control mechanism, a process device and a control mechanism are combined into a control group, and the control system includes a plurality of control groups; The control mechanism comprises: a CPU module (2), a signal processing unit (3), a collection control module (4) and a process operation module; A control signal is input through the signal control module (1) and sent to a CPU module (2) of a corresponding control group; the CPU module (2) performs calculations based on the received control signal and sends the result to a signal processing unit (3); the signal processing unit (3) sends the received signal to an acquisition control module (4); the acquisition control module (4) transmits the signal to a process operation module; the process operation module is installed on the process equipment and is divided into a plurality of process units according to different process operations, and adjusts the process equipment according to the received signal; the CPU module (2) and the signal processing unit (3) are installed in an SDT-4000 system controller; a plurality of numerical control instruments are provided on the process equipment, and the numerical control instruments are connected to the acquisition control module (4) to transmit state parameters in the process equipment to the acquisition control module (4).

2. A batch polypropylene device continuity control system according to claim 1, characterized in that: The signal control module (1) is controlled simultaneously by two control networks A and B, and the two networks A and B are independent of each other.

3. A batch polypropylene device continuity control system according to claim 1, characterized in that: The process equipment is a polymerization kettle (5) or a flash kettle (6).

4. A batch polypropylene device continuity control system according to claim 3, characterized in that: The outlet of the polymerization kettle (5) is connected to the flash kettle (6) via a material delivery pipeline, and a material discharge electric door (7) and a material load electric door (8) are sequentially provided on the material delivery pipeline.

5. A batch polypropylene device continuity control system according to claim 4, characterized in that: The loading electric door (8) and the unloading electric door (7) are respectively controlled by two independent AND logics, and the two signal sources of each AND logic are respectively from the collection control module (4) corresponding to the flash kettle (6) and the collection control module (4) corresponding to the polymerization kettle (5).

6. A batch polypropylene device continuity control system according to claim 1, characterized in that: The process units in the process operation module are independent of each other.

7. A batch polypropylene device continuity control system according to claim 6, characterized in that: The CPU module (2) comprises a plurality of mutually independent CPU units, and each process unit in the process operation module corresponds to an independent CPU unit in the CPU module (2).

8. A batch polypropylene device continuity control system according to claim 1, characterized in that: The numerical control instrument continuously monitors the production parameters in the process equipment in real time and transmits the transmitted signals to the CPU module (2).

Images