Unipol polypropylene device rapid shutdown system and method

Abstract

The invention discloses a rapid shutdown system and method for a Unipol polypropylene device. The rapid shutdown system is characterized in that a plurality of injection point positions are arranged at the upstream position of a reactor circulating gas pipeline of the Unipol polypropylene device; after cutting circulation of the catalyst, a terminator is injected into the reactor through the injection point positions, the terminator is a polar compound containing hydroxyl or amino, the injection amount is 1.2-1.5 times of the molar weight of the catalyst, and the reaction time is smaller than or equal to 5 min; after the reactor is terminated, reducing the pressure of the reactor to below 0.5 MPa at the speed of less than or equal to 0.3 MPa / min, and cutting out the propylene evaporator at the same time; nitrogen displacement, bed emptying and water system cut-out operations are executed in parallel in the pressure reduction process, the displacement gas flow is larger than or equal to 2000 Nm < 3 > / h, the bed height reduction rate is smaller than or equal to 1 m / h, and the starting time difference of all the steps is smaller than or equal to 2 min. And the efficiency, precision and stability can be obviously improved.

Description

Technical Field

[0001] The present invention relates to the field of Unipol polypropylene plants, and in particular to a rapid shutdown system and method for Unipol polypropylene plants. Background Art

[0002] During the shutdown process of traditional Unipol polypropylene plants, first, the catalyst addition amount is gradually reduced. When the load drops to a predetermined value, the catalyst is switched to circulation. At the same time, T2 (triethylaluminum) and SCA (electron donor) are continuously injected for about half an hour to consume the residual catalyst. Then, the reactor killing operation is carried out in sequence, using a specific chemical reagent to deactivate the active centers in the reactor; then, the reactor replacement is carried out, using an inert gas to replace the gas-phase components in the reactor; then, the bed layer is emptied to remove the polymer material in the bed layer; the reactor replacement is carried out again to further purify the reactor environment; then, the reactor hydrolysis is carried out to treat residual substances such as polymers and catalysts; then, the reactor is cooled down to reduce its internal temperature; the operation of the recycle gas compressor is stopped, the connection between the water system and the plant system is cut off, and finally the reactor is delivered for maintenance.

[0003] Objective drawbacks of the prior art:

[0004] 1. Long shutdown time: The entire shutdown process has cumbersome steps and requires long waiting times between steps. For example, the catalyst consumption process and multiple replacement and treatment operations result in the plant being in a shutdown transition state for a long time, reducing the annual effective operation time of the plant and increasing production costs.

[0005] 2. Waste of materials and energy: During the long shutdown process, equipment such as the recycle gas compressor continues to operate, consuming a large amount of electric energy. At the same time, during the reactor replacement, cooling down, etc., a large amount of material losses will occur, including unreacted monomers, catalysts, and inert gases. Summary of the Invention

[0006] The purpose of the present invention is to solve the above problems and design a rapid shutdown system and method for Unipol polypropylene plants.

[0007] To achieve the above purpose, the technical solution of the present invention is as follows. Further, in the above rapid shutdown system for Unipol polypropylene plants, the rapid shutdown system for polypropylene plants includes a jet point setting module, a terminator injection module, a reactor pressure reduction module, and a gas replacement module, where:

[0008] The jet point setting module is used to set a plurality of jet points at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene plant;

[0009] The terminator injection module is used to inject the terminator into the reactor through the injection point after the catalyst is switched to circulation. The terminator is a polar compound containing hydroxyl or amino groups, and the injection amount is 1.2 - 1.5 times the molar amount of the catalyst, and the reaction time is ≤ 5 min;

[0010] The reactor pressure reduction module is used to reduce the pressure of the reactor to below 0.5 MPa at a rate of ≤ 0.3 MPa / min after the reactor is terminated, and at the same time cut out the propylene evaporator;

[0011] The gas displacement module is used to perform nitrogen displacement, bed emptying and water system cut-out operations in parallel during the pressure reduction process, where the displacement gas flow rate is ≥ 2000 Nm 3 / h, the bed height decrease rate is ≤ 1 m / h, and the start time difference of each step is ≤ 2 min.

[0012] Furthermore, in the above-mentioned Unipol polypropylene plant rapid shutdown system, the terminator injection module includes the following real-time monitoring unit, data analysis unit, dynamic adjustment unit and reaction control unit, where:

[0013] The real-time monitoring unit is used to obtain the catalyst concentration data, temperature data and pressure data inside the reactor in real time through sensors;

[0014] The data analysis unit is used to analyze the catalyst concentration data, temperature data and pressure data using the PID control algorithm;

[0015] The dynamic adjustment unit is used to dynamically adjust the injection amount of the terminator according to the real-time concentration of the catalyst and the reaction progress;

[0016] The reaction control unit is used to obtain real-time feedback data through sensors and adjust the terminator injection rate through the real-time feedback data.

[0017] Furthermore, in the above-mentioned Unipol polypropylene plant rapid shutdown system, the terminator injection module includes a sensor unit, a pressure adjustment unit and a pressure judgment unit, where:

[0018] The sensor unit is used to obtain the pressure feedback data and temperature feedback data of the inner cylinder of the reactor using the sensors in the reactor;

[0019] The pressure adjustment unit is used to adjust the pressure release rate and pressure reduction path during the pressure reduction process using the dynamic algorithm for pressure feedback data and temperature feedback data;

[0020] The pressure judgment unit is used to judge the real-time pressure in the reactor, and cut out the propylene evaporator when the reactor pressure drops below 0.5 MPa.

[0021] Further, in the above-mentioned Unipol polypropylene plant rapid shutdown system, the gas displacement module includes a real-time monitoring unit and a nitrogen displacement unit, where:

[0022] The real-time monitoring unit is used to utilize MPC multivariable control prediction and optimization to coordinate various operations by real-time monitoring multiple parameters such as nitrogen flow rate, bed height drop rate, and pressure.

[0023] The nitrogen displacement unit is used to ensure that during the nitrogen displacement process, the gas flow rate ≥ 2000 Nm 3 / h, and at the same time, during the bed emptying process, the bed height drop rate is maintained ≤ 1 m / h.

[0024] Further, in the above-mentioned Unipol polypropylene plant rapid shutdown system, the gas displacement module includes a data acquisition unit, an operation prediction unit, and a target operation unit, where:

[0025] The data acquisition unit is used to obtain historical operation data of nitrogen displacement and bed emptying, and perform data preprocessing on the historical operation data. The historical operation data at least includes operation time, operation times, and operation quantities.

[0026] The operation prediction unit is used to establish a prediction model based on the LSTM long short-term memory network, input the preprocessed historical operation data into the prediction model for prediction, and obtain the target operation time.

[0027] The target operation unit is used to operate nitrogen displacement and bed emptying according to the target operation time.

[0028] In a method for rapid shutdown of a Unipol polypropylene plant, the method for rapid shutdown of the polypropylene plant includes:

[0029] Set a number of injection points at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene plant;

[0030] After the catalyst is switched to circulation, inject the terminator into the reactor through the injection points. The terminator is a polar compound containing hydroxyl or amino groups, and the injection amount is 1.2 - 1.5 times the molar amount of the catalyst, and the reaction time ≤ 5 min;

[0031] After the reactor is terminated, depressurize the reactor to below 0.5 MPa at a rate of ≤ 0.3 MPa / min, and at the same time cut out the propylene evaporator;

[0032] During the depressurization process, nitrogen displacement, bed emptying, and water system cut-out operations are performed in parallel, where the displacement gas flow rate ≥ 2000 Nm 3 / h, the bed height drop rate ≤ 1 m / h, and the start time difference of each step ≤ 2 min.

[0033] Furthermore, in the above-mentioned rapid shutdown method for Unipol polypropylene plant, several injection points are set at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene plant, including:

[0034] Obtain the catalyst concentration data, temperature data and pressure data inside the reactor in real time through sensors;

[0035] Analyze the catalyst concentration data, temperature data and pressure data by using the PID control algorithm; dynamically adjust the injection amount of the terminator according to the real-time concentration of the catalyst and the reaction progress;

[0036] Obtain real-time feedback data through sensors, and adjust the terminator injection rate through the real-time feedback data.

[0037] Furthermore, in the above-mentioned rapid shutdown method for Unipol polypropylene plant, after the reactor is terminated, the reactor is depressurized to below 0.5 MPa at a rate of ≤0.3 MPa / min, and at the same time, the propylene evaporator is cut out, including:

[0038] Obtain the pressure feedback data and temperature feedback data of the reactor inner cylinder by using the sensors in the reactor;

[0039] Use the dynamic algorithm to adjust the pressure release rate and pressure reduction path during the pressure reduction process according to the pressure feedback data and temperature feedback data;

[0040] Judge the real-time pressure in the reactor, and cut out the propylene evaporator when the reactor pressure drops below 0.5 MPa.

[0041] The beneficial effects are as follows: by setting several injection points at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene plant; after the catalyst is cut off from the cycle, the terminator is injected into the reactor through the injection points, the terminator is a polar compound containing hydroxyl or amino group, and the injection amount is 1.2 - 1.5 times the molar amount of the catalyst, and the reaction time is ≤5 min; after the reactor is terminated, the reactor is depressurized to below 0.5 MPa at a rate of ≤0.3 MPa / min, and at the same time, the propylene evaporator is cut out; during the pressure reduction process, nitrogen replacement, bed layer emptying and water system cutting operations are carried out in parallel, where the replacement gas flow rate ≥2000 Nm 3 / h, the bed layer height reduction rate ≤1 m / h, and the start time difference of each step ≤2 min. It can significantly improve the efficiency, accuracy and stability. The means of automation and intelligence not only reduce the risk of human error, but also optimize the operation process, ensuring the high efficiency, safety and economy of the reactor shutdown process. The shutdown time is shortened by 10% - 15%, and the annual effective operation time is increased by 5% - 8%. The energy consumption is reduced by 20% - 30%, and the losses of catalyst and monomer are reduced by 15% - 20%. Description of the Drawings

[0042] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention.

[0043] Figure 1 Schematic diagram of the first embodiment of a rapid shutdown system for a Unipol polypropylene plant in an embodiment of the present invention;

[0044] Figure 2 Schematic diagram of the second embodiment of a rapid shutdown system for a Unipol polypropylene plant in an embodiment of the present invention;

[0045] Figure 3 Schematic diagram of the third embodiment of a rapid shutdown system for a Unipol polypropylene plant in an embodiment of the present invention;

[0046] Figure 4 Schematic diagram of the first embodiment of a rapid shutdown method for a Unipol polypropylene plant in an embodiment of the present invention. Detailed implementation manners

[0047] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] Those skilled in the art of the present technology can understand that, unless specifically stated otherwise, the singular forms "a", "an", "" and "the" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention means the presence of features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0049] The present invention will be specifically described below with reference to the drawings, as Figure 1 shown, a rapid shutdown system for a Unipol polypropylene plant, the rapid shutdown system for the polypropylene plant includes a jet point setting module, a terminator injection module, a reactor pressure reduction module and a gas replacement module, wherein:

[0050] The jet point setting module is used to set a plurality of jet points at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene plant;

[0051] Specifically, in this embodiment, the terminator injection module includes the following real-time monitoring unit, data analysis unit, dynamic adjustment unit and reaction control unit, wherein:

[0052] A real-time monitoring unit, which is used to obtain the catalyst concentration data, temperature data and pressure data inside the reactor in real time through sensors;

[0053] A data analysis unit, which is used to analyze the catalyst concentration data, temperature data and pressure data by using the PID control algorithm;

[0054] A dynamic adjustment unit, which is used to dynamically adjust the injection amount of the terminator according to the real-time concentration of the catalyst and the reaction progress;

[0055] A reaction control unit, which is used to obtain real-time feedback data through sensors and adjust the injection rate of the terminator through the real-time feedback data.

[0056] Specifically, in this embodiment, the terminator injection module includes a sensor unit, a pressure adjustment unit and a pressure judgment unit, where:

[0057] The sensor unit is used to obtain the pressure feedback data and temperature feedback data of the inner cylinder of the reactor by using the sensors in the reactor;

[0058] The pressure adjustment unit is used to adjust the pressure release rate and the pressure reduction path during the pressure reduction process by using the dynamic algorithm for the pressure feedback data and the temperature feedback data;

[0059] The pressure judgment unit is used to judge the real-time pressure in the reactor. When the reactor pressure drops below 0.5 MPa, the propylene evaporator is cut out.

[0060] The terminator injection module is used to inject the terminator into the reactor through the injection point after the catalyst is switched to circulation. The terminator is a polar compound containing hydroxyl or amino groups, and the injection amount is 1.2 - 1.5 times the molar amount of the catalyst, and the reaction time ≤ 5 min;

[0061] The reactor pressure reduction module is used to reduce the pressure of the reactor to below 0.5 MPa at a rate of ≤ 0.3 MPa / min after the reactor is terminated, and at the same time cut out the propylene evaporator;

[0062] The gas displacement module is used to perform nitrogen displacement, bed layer emptying and water system cut-out operations in parallel during the pressure reduction process, where the displacement gas flow rate ≥ 2000 Nm 3 / h, the bed layer height reduction rate ≤ 1 m / h, and the start time difference of each step ≤ 2 min.

[0063] Specifically, in this embodiment, the gas displacement module includes a real-time monitoring unit and a nitrogen displacement unit, where:

[0064] The real-time monitoring unit is used to monitor multiple parameters such as nitrogen flow rate, bed height drop rate, and pressure in real time, and use MPC multivariable control to predict and optimize the coordination between various operations;

[0065] The nitrogen purging unit is used to ensure that during the nitrogen purging process, the gas flow rate ≥ 2000 Nm 3 / h, and at the same time, during the emptying of the bed layer, the bed height drop rate is maintained ≤ 1 m / h.

[0066] Specifically, in this embodiment, the gas replacement module further includes a data acquisition unit, an operation prediction unit, and a target operation unit, where:

[0067] The data acquisition unit is used to acquire the historical operation data of nitrogen purging and bed layer emptying, and perform data preprocessing on the historical operation data. The historical operation data at least includes operation time, operation times, and operation quantities;

[0068] The operation prediction unit is used to establish a prediction model based on the LSTM long short-term memory network, input the preprocessed historical operation data into the prediction model for prediction, and obtain the target operation time;

[0069] The target operation unit is used to operate nitrogen purging and bed layer emptying according to the target operation time.

[0070] The beneficial effects are as follows: By setting a number of injection points at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene plant; after the catalyst is switched to recycle, the terminator is injected into the reactor through the injection points. The terminator is a polar compound containing hydroxyl or amino groups, and the injection amount is 1.2 - 1.5 times the molar amount of the catalyst, and the reaction time ≤ 5 min; after the reactor is terminated, the reactor pressure is reduced to below 0.5 MPa at a rate ≤ 0.3 MPa / min, and at the same time, the propylene evaporator is cut out; during the pressure reduction process, nitrogen purging, bed layer emptying, and water system cut-out operations are performed in parallel, where the replacement gas flow rate ≥ 2000 Nm 3 / h, the bed height drop rate ≤ 1 m / h, and the start time difference between each step ≤ 2 min. It can significantly improve efficiency, accuracy, and stability. The means of automation and intelligence not only reduce the risk of human error, but also optimize the operation process, ensuring the high efficiency, safety, and economy of the reactor shutdown process. The shutdown time is shortened by 10% - 15%, and the annual effective operation time is increased by 5% - 8%. The energy consumption is reduced by 20% - 30%, and the catalyst and monomer losses are reduced by 15% - 20%.

[0071] A rapid shutdown procedure for a Unipol polypropylene plant is proposed. First, a special catalyst terminator is used to quickly terminate the catalyst activity. This terminator can efficiently react with the catalyst active centers in a short time, causing the catalyst to rapidly deactivate. After terminating the catalyst activity, a rapid pressure reduction operation of the reactor is immediately carried out. The propylene evaporator is preferably cut out first to reduce the addition of propylene. Subsequently, nitrogen is used to carry out operations such as reactor purging, bed emptying, and water system cut-out in parallel. By optimizing the connection and coordination between each operation step, the intermediate waiting time is reduced, and the shutdown efficiency is improved.

[0072] Key points and points to be protected

[0073] 1. Key points: The injection amount and usage method of the killing agent can quickly and thoroughly terminate the catalyst activity; the optimized shutdown operation process, especially the connection sequence and time control between each step, such as the coordination timing between the pressure reduction operation and other operations.

[0074] 2. Points to be protected: The injection method of the killing agent and its injection event in the shutdown of the Unipol polypropylene plant; the combination method of each operation step in the rapid shutdown procedure and key operation parameters, such as the pressure reduction rate, purging gas flow rate, etc.

[0075] Advantages:

[0076] 1. Significantly shorten the shutdown time: By quickly terminating the catalyst activity and optimizing the operation process, the waiting time during the shutdown is greatly reduced. The shutdown time of the plant can be shortened by more than 10%, improving the annual effective operation time of the plant and increasing the production capacity.

[0077] 2. Reduce material and energy consumption: Due to the shortened shutdown time, the running time of equipment such as the recycle gas compressor is reduced. At the same time, the loss of materials during the shutdown is reduced, and the waste of monomers, catalysts and other materials is reduced, thus reducing the production cost.

[0078] Please refer to Figure 2 , in a catalyst balance monitoring system for a DMTO plant based on rapid accounting, the terminator injection module includes the following real-time monitoring unit, data analysis unit, dynamic adjustment unit and control reaction unit, where:

[0079] The real-time monitoring unit is used to obtain the catalyst concentration data, temperature data and pressure data inside the reactor in real time through sensors;

[0080] The data analysis unit is used to analyze the catalyst concentration data, temperature data and pressure data using the PID control algorithm;

[0081] The dynamic adjustment unit is used to dynamically adjust the injection amount of the terminator according to the real-time concentration of the catalyst and the reaction progress;

[0082] A control reaction unit is used to obtain real-time feedback data through sensors and adjust the terminator injection rate based on the real-time feedback data.

[0083] Please refer to Figure 3 , in a catalyst balance monitoring system for a DMTO device based on rapid accounting, the terminator injection module includes a sensor unit, a pressure adjustment unit, and a pressure judgment unit, where:

[0084] The sensor unit is used to obtain the pressure feedback data and temperature feedback data of the inner cylinder of the reactor by using the sensors in the reactor;

[0085] The pressure adjustment unit is used to adjust the pressure release rate and pressure reduction path during the pressure reduction process by using the dynamic algorithm for pressure feedback data and temperature feedback data;

[0086] The pressure judgment unit is used to judge the real-time pressure in the reactor. When the reactor pressure drops below 0.5 MPa, the propylene evaporator is cut out.

[0087] The above introduces the embodiments of a rapid shutdown system for a Unipol polypropylene device of the present invention. Please refer to Figure 4 , in a method for rapid shutdown of a Unipol polypropylene device, the method for rapid shutdown of the polypropylene device includes the following steps:

[0088] Step 401: Set a number of injection points at the upstream position of the reactor recycle gas pipeline of the Unipol polypropylene device;

[0089] Step 402: After the catalyst is switched to circulation, inject the terminator into the reactor through the injection points. The terminator is a polar compound containing hydroxyl or amino groups, and the injection amount is 1.2 - 1.5 times the molar amount of the catalyst, and the reaction time ≤ 5 min;

[0090] Step 403: After the reactor is terminated, depressurize the reactor to below 0.5 MPa at a rate of ≤ 0.3 MPa / min, and at the same time cut out the propylene evaporator;

[0091] Step 404: During the pressure reduction process, perform nitrogen replacement, bed emptying, and water system cut-out operations in parallel, where the replacement gas flow rate ≥ 2000 Nm 3 / h, the bed height decrease rate ≤ 1 m / h, and the start time difference of each step ≤ 2 min.

[0092] Specifically, in this embodiment

[0093] 1. Catalyst terminator injection and reaction control:

[0094] During the traditional shutdown process, the injection amount of the catalyst terminator is usually preset within a fixed range. However, with the changes in catalyst activity and the internal state of the reactor, this preset injection amount may not always be optimal. To achieve more precise control, we can introduce an intelligent control system (such as an automated system based on PLC and sensors) to monitor the reactor state in real time and make adjustments.

[0095] Working principle of the intelligent control system:

[0096] Real-time monitoring: Obtain data such as catalyst concentration, temperature, and pressure inside the reactor in real time through sensors.

[0097] Data analysis and decision-making: The system uses algorithms (such as PID control or optimization models based on machine learning) to analyze this data. According to the real-time concentration of the catalyst and the reaction progress, it dynamically adjusts the injection amount of the terminator. This can ensure that the injection amount of the terminator always remains between 1.2 - 1.5 times the molar amount of the catalyst, rather than relying on manual operation.

[0098] Control of reaction time: Adjust the injection rate of the terminator through real-time feedback to ensure that the reaction time does not exceed 5 minutes, thus quickly and effectively stopping the reaction.

[0099] This method is more precise and flexible than traditional manual operation, can reduce human error, and ensure the efficiency and safety of the shutdown process.

[0100] Reactor pressure reduction process:

[0101] During the pressure reduction process, the pressure control of the reactor must be precise to avoid unnecessary pressure fluctuations or over - continuation of the reaction caused by too fast or too slow pressure reduction speed.

[0102] Dynamic optimization algorithm:

[0103] To ensure that the pressure reduction rate does not exceed 0.3 MPa / min, the system uses pressure and temperature feedback to adjust the pressure release rate during the pressure reduction process.

[0104] The control system will dynamically adjust the pressure reduction path according to the real - time data inside the reactor (such as changes in internal pressure and temperature of the reactor). For example, during the pressure reduction process, pressure changes and temperature changes are closely related. Too fast pressure reduction may cause a sudden drop in temperature, resulting in incomplete reaction or equipment damage. The dynamic algorithm can automatically adjust the pressure reduction rate according to these changes to avoid these risks.

[0105] Automatic switching operation: When the reactor pressure drops below 0.5 MPa, the system will automatically determine that the propylene evaporator should be cut out at this time to avoid excessive pressure reduction and reduce unnecessary energy waste.

[0106] This intelligent step-down control method reduces human intervention while improving the stability and safety of operations.

[0107] 3. Operations performed in parallel:

[0108] Nitrogen replacement, emptying of the bed layer, and isolation of the water system are several key steps that must be carried out simultaneously during the shutdown process. To efficiently coordinate these operations, a multivariable control algorithm can be used for parallel scheduling.

[0109] Multivariable control (MPC):

[0110] MPC is an advanced process control method that predicts and optimizes the coordination between various operations by real-time monitoring of multiple parameters such as nitrogen flow rate, the rate of decline in bed height, and pressure. It can ensure the optimal coordination of these operations under their mutual influence, avoiding conflicts or ineffective operations.

[0111] During the nitrogen replacement process, the system will automatically ensure that the gas flow rate ≥ 2000 Nm 3 / h, and at the same time, during the emptying of the bed layer, the rate of decline in bed height is maintained ≤ 1 m / h. The real-time adjustment of these parameters not only ensures the efficient execution of each operation but also reduces the time interval between operations, ensuring the continuity and stability of the entire shutdown process.

[0112] Through the application of this intelligent algorithm, all steps in the operation process are highly coordinated, thus avoiding unnecessary waste or redundancy.

[0113] 4. Precise control of terminator injection:

[0114] To ensure the uniform distribution of the catalyst terminator and improve the reaction efficiency, a multi-point injection system can be used. The core of this system is to set multiple injection points upstream of the reactor recycle gas pipeline to ensure that the catalyst terminator can evenly cover the entire reaction area, avoiding insufficient or excessive reactions in some areas.

[0115] Principle of the injection system:

[0116] Injection control: Through a precise PLC control system, the terminator can dynamically adjust the injection volume and injection rate according to the real-time data of the reactor (such as flow rate, temperature, reaction rate, etc.).

[0117] Multi-point injection: Different from traditional single-point injection, the multi-point injection system can ensure the uniform distribution of the terminator throughout the reaction area by installing injection points at different positions in the reactor gas pipeline. This not only improves the reaction efficiency of catalyst termination but also reduces the risk of local over-reaction.

[0118] Dynamic adjustment: Based on the feedback data of the real-time reactor, the control system can flexibly adjust the injection strategy to ensure the accuracy and efficiency of the injection operation.

[0119] This method significantly improves the utilization efficiency of the terminator, reduces the possible uneven distribution in the reactor, and thus improves the stability of the shutdown process.

[0120] 5. Operation overlap and timeliness optimization:

[0121] Nitrogen replacement and bed emptying are two operations that usually need to be carried out in parallel, but the optimization of their timing and overlap time is crucial. If handled improperly, it may lead to delays in the shutdown process and even affect the stability and safety of the equipment.

[0122] Timeliness optimization model:

[0123] By introducing regression analysis or neural network models, the system can predict the optimal overlap time of the operations. Through learning historical data, the model can predict the best start time of each step and the operation overlap time between the two, ensuring that the overlap time of nitrogen replacement and bed emptying is as close as possible to 80% of the total shutdown time.

[0124] Operation optimization: For example, the bed emptying operation can be started in advance when nitrogen replacement begins, which can maximize the time overlap of the operations and avoid the waste of time in separate operations. The optimization model will dynamically adjust the operation time to ensure that the shutdown process is as efficient and stable as possible.

[0125] By applying advanced optimization models, the system can find the best balance among multiple operations to ensure that each step can be completed in the shortest time.

[0126] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only the preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and the changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A Unipol polypropylene plant rapid shutdown system, characterized in that: The rapid shutdown system of the polypropylene device comprises an injection point setting module, a terminator injection module, a reactor pressure reduction module and a gas replacement module, wherein: An injection point setting module is used to set a number of injection points at the upstream position of the reactor circulating gas pipeline of the Unipol polypropylene device; A terminator injection module is used to inject the terminator into the reactor through the injection point after the catalyst is cut and circulated, wherein the terminator is a polar compound containing a hydroxyl group or an amino group, the injection amount is 1.2-1.5 times the molar amount of the catalyst, and the reaction time is ≤5min; The reactor depressurization module is used to reduce the pressure of the reactor to below 0.5MPa at a rate of ≤0.3MPa / min after the reactor is terminated, and the propylene evaporator is cut off at the same time; Gas replacement module, used to perform nitrogen replacement, bed emptying and water system cut-out operations in parallel during the depressurization process, where the replacement gas flow rate is ≥2000Nm 3 / h, the bed height drop rate ≤1m / h, and the start-up time difference of each step ≤2min.

2. A Unipol polypropylene plant rapid shutdown system as claimed in claim 1, characterized in that: The terminator injection module includes the following real-time monitoring unit, data analysis unit, dynamic adjustment unit and control reaction unit, wherein: A real-time monitoring unit, used to obtain catalyst concentration data, temperature data and pressure data inside the reactor in real time through sensors; A data analysis unit, used to analyze catalyst concentration data, temperature data and pressure data using a PID control algorithm; A dynamic adjustment unit is used to dynamically adjust the injection amount of the terminator according to the real-time concentration of the catalyst and the reaction progress; The control reaction unit is used to obtain real-time feedback data through a sensor and adjust the terminator injection rate according to the real-time feedback data.

3. A Unipol polypropylene plant rapid shutdown system as claimed in claim 1, characterized in that: The terminator injection module includes a sensor unit, a pressure adjustment unit and a pressure judgment unit, wherein: A sensor unit, used for obtaining pressure feedback data and temperature feedback data of the inner cylinder of the reactor by using sensors in the reactor; A pressure adjustment unit, used to adjust the pressure release rate and pressure reduction path during the pressure reduction process using dynamic algorithm pressure feedback data and temperature feedback data; The pressure judgment unit is used to judge the real-time pressure in the reactor and cut out the propylene evaporator if the reactor pressure drops below 0.5MPa.

4. A Unipol polypropylene plant rapid shutdown system as claimed in claim 1, characterized in that: The gas replacement module includes a real-time monitoring unit and a nitrogen replacement unit, wherein: Real-time monitoring unit, which is used to monitor multiple parameters such as nitrogen flow rate, bed height drop rate and pressure in real time, and use MPC multivariable control to predict and optimize the coordination between various operations; Nitrogen replacement unit, used in the nitrogen replacement process, gas flow ≥ 2000Nm 3 / h, and during the bed emptying process, keep the bed height descending rate ≤1m / h.

5. A Unipol polypropylene plant rapid shutdown system as claimed in claim 1, characterized in that: The gas replacement module includes a data acquisition unit, an operation prediction unit and a target operation unit, wherein: A data acquisition unit, used to acquire historical operation data of nitrogen replacement and bed emptying, and perform data preprocessing on the historical operation data, wherein the historical operation data at least includes operation time, operation times, and operation quantity; The operation prediction unit is used to establish a prediction model based on the LSTM long short-term memory network, input the preprocessed historical operation data into the prediction model for prediction, and obtain the target operation time; The target operation unit is used to operate nitrogen replacement and bed emptying according to the target operation time.

6. A method for rapid shutdown of a Unipol polypropylene plant, characterized in that: The polypropylene device rapid shutdown method comprises: Several injection points are set at the upstream position of the reactor circulation gas pipeline of the Unipol polypropylene unit; After the catalyst is circulated, a terminator is injected into the reactor through the injection point, wherein the terminator is a polar compound containing a hydroxyl group or an amino group, and the injection amount is 1.2-1.5 times the molar amount of the catalyst, and the reaction time is ≤5min; After the reactor is terminated, the reactor pressure is reduced to below 0.5 MPa at a rate of ≤0.3 MPa / min, and the propylene evaporator is cut off at the same time; During the depressurization process, nitrogen replacement, bed emptying and water system cut-out operations are performed in parallel, and the replacement gas flow rate is ≥2000Nm 3 / h, the bed height drop rate ≤1m / h, and the start-up time difference of each step ≤2min.

7. A method for rapid shutdown of a Unipol polypropylene plant as claimed in claim 7, characterized in that: The method comprises setting a plurality of injection points at the upstream position of the reactor circulating gas pipeline of the Unipol polypropylene device, including: The catalyst concentration data, temperature data and pressure data inside the reactor are obtained in real time through sensors; Analyze catalyst concentration data, temperature data and pressure data using PID control algorithm; dynamically adjust the injection amount of terminator according to the real-time concentration of the catalyst and the reaction progress; Real-time feedback data is obtained through the sensor, and the terminator injection rate is adjusted according to the real-time feedback data.

8. A Unipol polypropylene plant rapid shutdown system as claimed in claim 7, characterized in that: After the reactor is terminated, the reactor pressure is reduced to below 0.5 MPa at a rate of ≤0.3 MPa / min, and the propylene evaporator is cut out at the same time, comprising: Using sensors in the reactor to obtain pressure feedback data and temperature feedback data of the inner barrel of the reactor; Use dynamic algorithm pressure feedback data and temperature feedback data to adjust the pressure release rate and pressure reduction path during the pressure reduction process; The real-time pressure in the reactor is judged, and the propylene evaporator is cut out if the reactor pressure drops below 0.5 MPa.

Images