Shell gasifier pulverized coal pressurizing system sequence control system and method thereof

Abstract

The application discloses a Shell gasifier pulverized coal pressurizing system sequence control system and method, through the DCS sequence control program, the whole process of loading, pressurizing, discharging, pressure relief and reloading of the pulverized coal lock hopper is automatically executed, replacing the traditional manual operation mode, greatly reducing the labor intensity of the operator, and eliminating the risk of human operation failure. Through the multi-stage ladder type pressurizing strategy and the automatic use of the pressure fine adjustment valve, combined with the automatic setting of the PID parameter, the pressure control precision of the pulverized coal lock hopper is greatly improved, effectively preventing the occurrence of equipment overpressure accidents and prolonging the service life of the equipment. Through the real-time collection of process parameters by the set material level monitoring device, pressure monitoring device and pressure difference monitoring device, the DCS sequence control program can automatically judge abnormal working conditions such as the pulverized coal bridging and start the bridge elimination sub-program, so that the bridging can be eliminated without manual intervention, the gasification furnace under-feeding shutdown accident caused by the bridging is avoided, and the continuous, safe and stable operation of the gasification furnace is ensured.

Description

Technical Field

[0001] This invention relates to the field of coal chemical automation control technology, specifically to a sequential control system and method for a Shell gasifier pulverized coal pressurization system. Background Technology

[0002] The Shell gasifier pulverized coal pressurization system is a crucial process control component for the safe operation of the gasifier. Its function is to pressurize and deliver qualified pulverized coal prepared upstream to the gasifier burners, ensuring the continuous and stable operation of the gasifier. The pulverized coal pressurization system mainly includes a pulverized coal storage silo, a pulverized coal lock hopper, and a pulverized coal feed tank. Among them, the pulverized coal lock hopper is a key buffer device connecting the atmospheric pressure pulverized coal storage silo and the high-pressure pulverized coal feed tank, and it needs to alternate between atmospheric pressure charging and high-pressure unloading.

[0003] In existing technologies, the operation of the pulverized coal lock hopper in Shell gasifier pulverized coal pressurization systems is typically performed manually by operators. During gasifier system operation, for example, if the valve connecting the low-pressure coal bunker and the high-pressure coal lock malfunctions, gas from the high-pressure coal lock can leak into the low-pressure coal bunker, causing damage to the bunker's rupture discs and overpressure deformation of the equipment. The ejection of large amounts of pulverized coal can also cause environmental pollution and fire accidents, further increasing the risk of personnel injury. Simultaneously, during coal lock operation, insufficient coal feeding frequently occurs, sometimes leading to emergency shutdown of the gasifier, directly impacting the gasifier's operational safety and economic efficiency.

[0004] The inventors discovered that the traditional manual operation method has the following technical problems: (1) Operators need to manually adjust each step of the coal lock sequential control program. During the adjustment process, not only does it increase the labor intensity of operators, but the inaccurate control of pressure points also causes the valves of the coal lock system equipment to be unable to be completely closed, directly causing overpressure in the coal bunker and coal lock equipment and coal powder leakage; (2) Frequent use of manual operation of coal lock sequential control makes it impossible to accurately control the coal powder level, which directly leads to the gasifier running out of material and stopping, thereby affecting the service life and safety of the equipment valves; (3) It does not have the ability to automatically and accurately adjust the sequential control, and the PID parameters of the sequential control logic cannot be accurately adjusted; (4) The manual operation has poor accuracy and does not have the ability to automatically adjust and judge, and cannot automatically adjust the control strategy according to the real-time changes of process parameters.

[0005] To solve the above problems, the inventors, based on the logical relationship of the actual coal bunker and coal lock operation sequence control, independently developed a sequential automatic control method and process using a computer control system. Through the DCS sequential control program, the operation of each valve in the pulverized coal pressurization system is automatically controlled, realizing the fully automatic pressurization and transportation of pulverized coal from the pulverized coal storage silo through the pulverized coal lock hopper to the pulverized coal feeder, thus solving the operational problem of manual adjustment. Summary of the Invention

[0006] To address the aforementioned problems, the first objective of this invention is to provide a sequential control system for a Shell gasifier pulverized coal pressurization system, and the second objective of this invention is to provide a sequential control method for a Shell gasifier pulverized coal pressurization system.

[0007] The first objective of this invention is achieved by the following technical solution: A sequential control system for a Shell gasifier pulverized coal pressurization system includes a pulverized coal storage silo, a pulverized coal lock hopper, a pulverized coal feed tank, a high-pressure inert gas source, a detection unit, a control unit, and an execution unit; The outlet of the pulverized coal storage bin is connected to the inlet of the pulverized coal lock hopper via a first feeding pipeline, and the outlet of the pulverized coal lock hopper is connected to the inlet of the pulverized coal feed tank via a second feeding pipeline; the outlet of the pulverized coal lock hopper is also connected to the inlet of the pulverized coal feed tank via a balancing pipeline, and the outlet of the pulverized coal feed tank is connected to the inlet of the gasifier. The pulverized coal lock hopper is also connected to the inlet of the bag filter via a pressure relief pipeline; the outlet of the high-pressure inert gas source is connected to the pressurization port at the top of the pulverized coal lock hopper via a pressurization pipeline. The detection unit includes a weighing monitoring device installed on the pulverized coal storage silo, a first high-level monitoring device and a first low-level monitoring device installed on the pulverized coal lock hopper, a pressure monitoring device installed on the pulverized coal lock hopper, a second high-level monitoring device and a second low-level monitoring device installed on the pulverized coal feed hopper, a discharge pressure differential monitoring device installed on the balance pipeline, a pressurization process pressure differential monitoring device, a pressure equalization completion pressure differential monitoring device and a bridging elimination pressure differential monitoring device, and a pressure relief pressure differential monitoring device installed between the pulverized coal lock hopper and the pulverized coal storage silo. The execution unit includes a first connecting valve and a second connecting valve disposed on the first discharge pipeline, a pressure fine adjustment valve disposed on the first discharge pipeline between the first connecting valve and the second connecting valve, a first discharge valve and a second discharge valve disposed on the second discharge pipeline, a first balancing valve and a second balancing valve disposed on the balancing pipeline, a first pressure relief valve, a second pressure relief valve, a third pressure relief valve and a fourth pressure relief valve disposed on the pressure relief pipeline, and a pressure charging valve, a high-pressure carbon dioxide pressure charging flow regulating valve and a pressure charging flow differential pressure regulating valve disposed on the pressure charging pipeline. The signal output terminals of each monitoring device in the detection unit are connected to the signal input terminals of the control unit, and the signal output terminals of the control unit are connected to the signal input terminals of each execution device in the execution unit.

[0008] Furthermore, the pulverized coal lock hopper is also connected to an air-filled whistle fluidization pipeline, which is equipped with a fluidization valve and is connected to the high-pressure carbon dioxide gas source; the pulverized coal lock hopper is also connected to an air-filled cone pressurization pipeline, which is equipped with an air-filled cone pressurization valve and a pulverized coal lock hopper air-filled cone regulating valve and is connected to the high-pressure carbon dioxide gas source; the pulverized coal storage bin is connected to a low-pressure nitrogen gas flow fluidization pipeline, which is equipped with a first fluidization valve and a second fluidization valve and is connected to a low-pressure nitrogen gas source.

[0009] Furthermore, the pulverized coal lock hopper is also connected to a pressurization and backflushing pipeline, which is equipped with a pressurization valve and is also connected to a high-pressure gas pipeline network.

[0010] The second objective of this invention is achieved by the following technical solution: A sequential control method for a Shell gasifier pulverized coal pressurization system includes the following steps: S1. Feeding Start-up and Discharge Steps: When the pulverized coal feed hopper reaches the low material level, the fluidization operation of the pulverized coal storage bin is executed and the discharge valve of the pulverized coal lock hopper is opened. When the preset differential pressure condition is met, the pulverized coal lock hopper discharges material into the pulverized coal feed hopper. At the same time, the material level signal and timing results are used to determine whether the discharge is completed normally. If bridging abnormality occurs, the process is switched to the anti-bridging subroutine. S2. High-pressure side isolation and depressurization steps: After the material is fed, close the high-pressure side valve connected to the pulverized coal feed tank in sequence to isolate the pulverized coal lock hopper. Then, open the depressurization valve step by step according to the multi-stage step depressurization strategy to release the pressure of the pulverized coal lock hopper to a low-pressure state. S3. Low-pressure side loading procedure: After depressurization, open the connecting valve between the pulverized coal storage bin and the pulverized coal lock hopper to allow the pulverized coal in the pulverized coal storage bin to fall into the pulverized coal lock hopper. Determine whether the loading is complete by weighing and material level monitoring. After completion, close the connecting valve to isolate the pulverized coal lock hopper. S4. Pressurization and equalization steps: Perform multi-stage step pressurization on the pulverized coal lock hopper after it has been loaded. Open the pressurization valves at each stage according to the preset pressure increase conditions. After the pressure of the pulverized coal lock hopper is raised to the target pressure value, open the balance valve between the pulverized coal lock hopper and the pulverized coal feed tank to equalize the pressure of the two tanks. S5. Looping Waiting and Stopping Steps: After pressure equalization, the sequential control program enters the standby waiting state, waiting for the pulverized coal feeder to show a low material level signal again before returning to step S1, or responding to the stop signal to execute the shutdown procedure and return to the initialization state.

[0011] Furthermore, the S1 feeding start and unloading steps specifically include the following steps: S11. In response to the low material level signal of the pulverized coal feeder, open the second fluidization valve of the pulverized coal storage silo to fluidize the pulverized coal, and open the second discharge valve of the pulverized coal lock hopper. S12. When the pressure difference monitoring device detects that the pressure difference in the balance pipeline reaches 0.59MPa, open the fluidization valve of the pulverized coal lock hopper; when the pressure difference in the balance pipeline meets the conditions or the fluidization valve is fully open and the second discharge valve is open, open the first discharge valve of the pulverized coal lock hopper; if the pressure monitoring device shows that the pressure of the pulverized coal lock hopper is higher than the pressure of the pulverized coal feeder by more than 1MPa, first open the air-filling cone pressurization valve, and then open the first discharge valve after a 5-second delay. S13. Close the fluidization valve 5 seconds after the first feed valve opens; start the coal feeding timer, open the pressurization valve, and set the high-pressure carbon dioxide pressurization flow regulating valve to automatic setting of 40 Nm. 3 / h, set the pressure differential regulating valve for pressurization flow rate to 350kPa; S14. After a 30-second delay or when the first low-level monitoring device detects a low-level signal, close the pressurization valve and manually close the high-pressure carbon dioxide pressurization flow regulating valve and the pressurization flow differential pressure regulating valve. S15. After the material feeding is completed, if the first low material level monitoring device generates a low material level signal and the coal feeding time has expired or the process is manually overridden, proceed to step S2; if the coal feeding time has not expired but the low material level signal is triggered, or the low material level signal does not appear, proceed to the bridge elimination sub-program.

[0012] Furthermore, the S2 high-voltage side isolation and depressurization step specifically includes the following steps: S21: Open the first pressure relief valve of the pulverized coal lock hopper, and close the first pressure relief valve after the pressure monitoring device shows that the pressure of the pulverized coal lock hopper has dropped to 2.0MPa; S22: Open the second pressure relief valve of the pulverized coal lock hopper. When the pressure monitoring device shows that the pressure of the pulverized coal lock hopper drops to 0.25MPa and the pressure difference monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal storage silo is less than 0.15MPa, open the third and fourth pressure relief valves of the pulverized coal lock hopper to ensure the pressure balance between the pulverized coal storage silo and the pulverized coal lock hopper.

[0013] Furthermore, the S3 low-pressure side loading step specifically includes the following steps: S31: Close the second pressure relief valve and open the first fluidization valve of the pulverized coal storage silo; S32: After confirming the valve position, first open the second connecting valve between the pulverized coal storage bin and the pulverized coal lock hopper, then open the first connecting valve, and close the first fluidization valve after a 10-second delay, and start the pulverized coal storage bin feeding timer. S33: When the first high material level monitoring device displays a high material level signal, or the feeding timer reaches the preset time, or when manually operated, the first connecting valve is closed first, the weight of the pulverized coal storage bin is recorded, and then the second connecting valve, the third pressure relief valve, and the fourth pressure relief valve are closed to complete the isolation.

[0014] Furthermore, step S4, the pressurization and equalization step, specifically includes the following steps: S41: Open the pressurization valve to pressurize the pulverized coal lock hopper and backflush the bag filter. After a delay, open the charging valve and put the high-pressure carbon dioxide charging flow regulating valve and the charging stage differential pressure regulating valve into automatic mode. S42: When the pressure monitoring device shows that the pulverized coal lock hopper pressure reaches 0.9MPa, open the fluidization valve; when the pulverized coal lock hopper pressure reaches 1.0MPa, open the air-charging cone pressure valve and put the pulverized coal lock hopper air-charging cone regulating valve into automatic mode; when the pressure difference monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal feed tank reaches 0.45MPa during the pressurization process, close the pressurization valve; when the pressure difference reaches 0.25MPa, close the pressurization valve and put the high-pressure carbon dioxide pressurization flow regulating valve and the pressurization stage pressure difference regulating valve into manual mode; when the pressure difference reaches 0.02MPa, close the fluidization valve. S43: When the pressure monitoring device shows that the pulverized coal lock hopper pressure is not greater than 1MPa, close the air charging cone pressurization valve, open the pressure fine adjustment valve and put the fine adjustment differential pressure regulating device into automatic mode, and adjust the pulverized coal lock hopper pressure to stabilize at 4.95MPa; S44: When the pressure equalization is completed and the differential pressure monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal feeder is maintained between ±0.01MPa for 10 seconds, the pressure fine adjustment valve is closed. After it is closed, the first balance valve and the second balance valve are opened to equalize the pressure of the two tanks.

[0015] Furthermore, the S5, loop waiting and stopping step specifically includes the following steps: S51: After confirming the valve position, check if there is a stop signal in the sequential control program. If there is no stop signal, the sequential control enters the standby waiting state, waiting for the second low material level monitoring device to detect the low material level of the pulverized coal feeder and trigger it again, and then return to step S1. S52: If a stop signal is received, the rotating feeder will stop, the screw conveyor will stop after a delay, and the system will return to the initialization state.

[0016] Furthermore, the bridge clearing subroutine includes the following steps: S101: Open the pressurization valve and fluidization valve to fluidize the pulverized coal and begin eliminating bridging; S102: After confirming that the fluidization valve is closed and the feedback is normal, close the first feed valve and the second balance valve to isolate the pulverized coal lock hopper from the pulverized coal feed tank; S103: After confirming that the first feeding valve, the second balancing valve and the pressurizing valve are closed normally, and after the anti-bridging pressure differential monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal feeder reaches 150 kPa, open the first feeding valve, close the fluidization valve after a 5-second delay, and open the second balancing valve after a 20-second delay, using the pressure difference as the power to eliminate bridging. S104: When the first low material level monitoring device detects a low material level signal in the pulverized coal lock hopper, execute step S105; if the low material level signal in the pulverized coal lock hopper does not appear, reset the bridge elimination mechanism and return to step S101. S105: After executing step S104, close the first discharge valve, close the air cone pressurization valve, and return to step S2; S106: The operator performs overdrive as needed, closes the air cone pressurization valve, and closes the first discharge valve after a 5-second delay, returning to step S2.

[0017] Advantages of this invention: The DCS sequential control program automatically executes the entire process of loading, pressurizing, unloading, depressurizing, and reloading of the pulverized coal lock hopper, completely replacing the traditional manual operation method. This significantly reduces the labor intensity of operators and eliminates the risk of human error. Through a multi-stage stepped pressurization strategy and the automatic activation of pressure fine-tuning valves, combined with automatic PID parameter tuning, the pressure control accuracy of the pulverized coal lock hopper is greatly improved, effectively preventing overpressure accidents and extending equipment lifespan. By using material level monitoring devices, pressure monitoring devices, and differential pressure monitoring devices to collect process parameters in real time, the DCS sequential control program can automatically identify abnormal operating conditions such as pulverized coal bridging based on parameter changes and activate the anti-bridging subroutine. Bridging can be eliminated without manual intervention, avoiding gasifier shutdown accidents caused by bridging and ensuring the continuous, safe, and stable operation of the gasifier. This invention shortens the coal feeding cycle from 25 minutes to 20 minutes, improving the efficiency of pulverized coal conveying; extends the valve damage cycle and increases equipment operating rate, reducing maintenance costs; and the dual-valve group isolation between high and low pressure equipment and strict differential pressure control conditions effectively prevent accidents caused by high-pressure gas entering low-pressure equipment, eliminating environmental pollution and fire hazards caused by pulverized coal leakage. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the connection of the pulverized coal storage silo in Example 1; Figure 2 This is a schematic diagram of the connection of the pulverized coal lock hopper in Example 1; Figure 3 This is a schematic diagram of the connection of the pulverized coal feeder in Example 1. In the diagram: 1. Pulverized coal storage bin; 2. Pulverized coal lock hopper; 3. Pulverized coal feeder; 4. Bag filter; 5. Balancing pipeline; 6. Rotary feeder; 7. Screw conveyor; 8. Second fluidizing valve; 9. Second pressure relief valve; 10. First fluidizing valve; 11. Fourth pressure relief valve; 12. Third pressure relief valve; 13. First pressure relief valve; 14. Second connecting valve; 15. Pressure fine adjustment valve; 16. Pressurizing valve; 17. First balancing valve; 18. Second balancing valve; 19. Fluidizing valve; 20. Pressurizing valve; 21. Pressurizing cone valve; 22. First discharge valve; 23. Second discharge valve; 24. First connecting valve; 25. High-pressure carbon dioxide pressurizing flow regulating valve. 5; Coal powder lock hopper air filling cone regulating valve - 26; Weighing monitoring device - 27; First high material level monitoring device - 28; First low material level monitoring device - 29; Pressure monitoring device - 30; Second high material level monitoring device - 31; Second low material level monitoring device - 32; Feeding pressure differential monitoring device - 33; Pressurization process pressure differential monitoring device - 34; Pressure equalization completion pressure differential monitoring device - 35; Anti-bridging pressure differential monitoring device - 36; Pressure relief pressure differential monitoring device - 37; Pressurization flow pressure differential regulating valve - 38; Pressurization stage pressure differential regulating valve - 39; Fine adjustment pressure differential regulating device - 40; Low-pressure nitrogen source - 41; High-pressure carbon dioxide source - 42; High-pressure gas pipeline network - 43. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 Taking a pulverized coal pressurized conveying unit of a coal chemical enterprise using Shell's downflow quench coal gasification process as an example, this unit includes two series, A and B. This embodiment uses series A as an example for explanation. Figures 1 to 3 As shown, a Shell gasifier pulverized coal pressurization system sequential control system includes a pulverized coal storage silo 1, a pulverized coal lock hopper 2, a pulverized coal feed tank 3, a high-pressure inert gas source, a detection unit, a control unit, and an execution unit.

[0021] The top inlet of the pulverized coal storage silo 1 is connected to the pulverized coal bag filter of the upstream coal mill and drying system via a pipeline to receive qualified pulverized coal from upstream. The bottom outlet of the pulverized coal storage silo 1 is connected to the top inlet of the pulverized coal lock hopper 2 via a first discharge pipeline. This first discharge pipeline is equipped with a first connecting valve 24, a pressure fine-tuning valve 15, and a second connecting valve 14 sequentially from upstream to downstream. The pressure fine-tuning valve 15 is located between the first connecting valve 24 and the second connecting valve 14. The two connecting valves are arranged in series as a safety isolation between the atmospheric pressure side and the high pressure side. A weighing monitoring device 27 is installed on the pulverized coal storage silo 1 to monitor the weight of the pulverized coal in the silo in real time, providing data for sequential control to determine whether the conditions for discharge are met. The pulverized coal storage silo 1 is also connected to a low-pressure nitrogen gas flow pipeline, which is connected to a low-pressure nitrogen source 41. The pipeline is equipped with a first fluidization valve 10 and a second fluidization valve 8, which are used to introduce low-pressure nitrogen into the pulverized coal storage silo to fluidize the pulverized coal and facilitate smooth pulverized coal feeding.

[0022] The top inlet of the pulverized coal lock hopper 2 is connected to the first discharge pipeline to receive pulverized coal from the pulverized coal storage silo 1; its bottom outlet is connected to the top inlet of the pulverized coal feed tank 3 via a second discharge pipeline. The second discharge pipeline is equipped with a first discharge valve 22 and a second discharge valve 23, arranged in series as a safety isolation between the pulverized coal lock hopper and the pulverized coal feed tank. A balancing pipeline is also connected between the pulverized coal lock hopper 2 and the pulverized coal feed tank 3, equipped with a first balancing valve 17 and a second balancing valve 18 for pressure balancing between the pulverized coal lock hopper and the pulverized coal feed tank. A pressure relief pipeline is connected between the pulverized coal lock hopper 2 and the bag filter 4, equipped with a first pressure relief valve 13, a second pressure relief valve 9, a third pressure relief valve 12, and a fourth pressure relief valve 11 for staged pressure relief within the pulverized coal lock hopper to atmospheric pressure. Pulverized coal entrained during the pressure relief process is filtered and recovered by the bag filter 4.

[0023] The pressurization port of the pulverized coal lock hopper 2 is connected to a high-pressure carbon dioxide gas source 42 via a pressurization pipeline. The pressurization pipeline is equipped with a pressurization valve 20, a high-pressure carbon dioxide pressurization flow regulating valve 25, a pressurization flow differential pressure regulating valve 38, and a pressurization stage differential pressure regulating valve 39, used to introduce high-pressure carbon dioxide into the pulverized coal lock hopper for pressurization and to precisely regulate the flow rate and differential pressure during the pressurization process. The pulverized coal lock hopper 2 is also connected to a fluidization pipeline with an air filling whistle, which is connected to the high-pressure carbon dioxide gas source 42. This pipeline is equipped with a fluidization valve 19 for fluidizing the pulverized coal during feeding. The pulverized coal lock hopper 2 is also connected to an air filling cone pressurization pipeline, which is connected to the high-pressure carbon dioxide gas source 42. This pipeline is equipped with an air filling cone pressurization valve 21 and a pulverized coal lock hopper air filling cone regulating valve 26, used for fine pressure regulation in the later stages of pressurization. The pulverized coal lock hopper 2 is also connected to a pressurization and backflushing pipeline, which is connected to the high-pressure gas pipeline network 43. A pressurization valve 16 is installed on the pipeline to pressurize the pulverized coal lock hopper 2 and backflush the bag filter 4. The pulverized coal lock hopper 2 is equipped with a first high material level monitoring device 28 and a first low material level monitoring device 29, which are used to monitor the high material level and low material level of the pulverized coal lock hopper 2, respectively; at the same time, a pressure monitoring device 30 is also installed to monitor the pressure inside the pulverized coal lock hopper in real time.

[0024] The top inlet of the pulverized coal feeder 3 is connected to the second discharge pipeline to receive pulverized coal from the pulverized coal lock hopper 2; its bottom outlet is connected to the pulverized coal burner of the gasifier through the pulverized coal conveying pipeline, continuously conveying the pressurized pulverized coal to the gasifier. The pulverized coal feeder 3 is equipped with a second high-level monitoring device 31 and a second low-level monitoring device 32 to monitor the material level in the pulverized coal feeder in real time. When the material level drops to the low level, a sequential control start signal is triggered.

[0025] The detection unit includes: a weighing monitoring device 27 installed on the pulverized coal storage silo 1; a first high-level monitoring device 28, a first low-level monitoring device 29, and a pressure monitoring device 30 installed on the pulverized coal lock hopper 2; a second high-level monitoring device 31 and a second low-level monitoring device 32 installed on the pulverized coal feed hopper 3; and a first differential pressure monitoring device installed on the balance pipeline 5, including a discharge differential pressure monitoring device 33, a pressurization process differential pressure monitoring device 34, a pressure equalization completion differential pressure monitoring device 35, and a bridging elimination differential pressure monitoring device 36, which are used to monitor the differential pressure between the pulverized coal lock hopper and the pulverized coal feed hopper at different stages—specifically, the discharge differential pressure monitoring device. The differential pressure monitoring device 33 is used to monitor whether the differential pressure of the balancing pipeline meets the feeding condition of 0.59 MPa. The differential pressure monitoring device 34 during the pressurization process is used to monitor the differential pressure between the two tanks during the pressurization process to determine whether the pressurization stage is completed. The differential pressure monitoring device 35 after pressure equalization is used to monitor whether the differential pressure between the two tanks is stable within the range of 0.01 MPa. The differential pressure monitoring device 36 for eliminating bridging is used to monitor whether the differential pressure during the elimination of bridging reaches 150 kPa. The pressure relief differential pressure monitoring device 37, which is installed between the pulverized coal lock hopper 2 and the pulverized coal storage silo 1, is used to monitor the differential pressure between the pulverized coal lock hopper and the pulverized coal storage silo to ensure pressure balance after pressure relief is completed.

[0026] The control unit is a DCS controller, connected to the signals of each monitoring device in the detection unit to receive feedback signals from each monitoring device; it is also connected to the control of each execution device in the execution unit to automatically control each execution device to perform switching and adjustment actions in sequence according to the feedback signals from each monitoring device and a preset sequential control logic. The execution unit includes: a first connecting valve 24, a second connecting valve 14, and a pressure fine-tuning valve 15 located between the two on the first feeding pipeline, and a matching fine-tuning differential pressure regulating device 40; a first feeding valve 22 and a second feeding valve 23 on the second feeding pipeline; a first balancing valve 17 and a second balancing valve 18 on the balancing pipeline; and a first pressure relief valve 13, a second pressure relief valve 9, a third pressure relief valve 12, and a fourth pressure relief valve on the pressure relief pipeline. 11; A pressurizing valve 20, a high-pressure carbon dioxide pressurizing flow regulating valve 25, and a pressurizing flow differential pressure regulating valve 38 are installed on the pressurizing pipeline; a fluidizing valve 19 is installed on the fluidizing pipeline of the air-filling whistle pipe; an air-filling cone pressurizing valve 21 and a pulverized coal lock hopper air-filling cone regulating valve 26 are installed on the air-filling cone pressurizing pipeline; a first fluidizing valve 10 and a second fluidizing valve 8 are installed on the low-pressure nitrogen flow fluidizing pipeline; a pressurizing valve 16 is installed on the pressurizing and backflushing pipelines; and a rotary feeder 6 and a screw conveyor 7. All of the above valves are pneumatically operated on / off valves or pneumatically operated regulating valves.

[0027] Example 2 Under normal operating conditions, the initial state is that the pulverized coal lock hopper 2 is under high pressure and full, all inlet and outlet valves are closed, and the balance line between it and the pulverized coal feed tank 3 is open. Simultaneously, the pulverized coal storage silo 1 is filled with more than 30 tons of pulverized coal. In the initial state, the second pressure relief valve 9, the first fluidization valve 10, the fourth pressure relief valve 11, the third pressure relief valve 12, the first pressure relief valve 13, the second connecting valve 14, the pressure fine-tuning valve 15, the pressurizing valve 16, the fluidization valve 19, the charging valve 20, the air-charging cone charging valve 21, the first discharge valve 22, the second discharge valve 23, and the first connecting valve 24 are in the closed position, while the first balance valve 17 and the second balance valve 18 are in the open position. When all the above conditions are met and the operator starts the pulverized coal pressurization device sequential control program, the sequential control begins automatic operation.

[0028] The method for sequential control using the sequential control system of the Shell gasifier pulverized coal pressurization system provided in Example 1 is as follows: Step S1: Feeding Start and Discharging After the sequential start-up, the first stage is the feeding and unloading stage. When the second low level monitoring device 32 of the pulverized coal feed tank 3 sends a low level signal and confirms it after a 5-second delay, the DCS controller executes sub-step S11: open the second fluidization valve 8 of the pulverized coal storage silo 1, and introduce low-pressure nitrogen into the pulverized coal storage silo 1 to fluidize the pulverized coal so that the unloading is smooth. At the same time, open the second unloading valve 23 of the pulverized coal lock hopper 2. Opening this valve first can prevent blockage when the pulverized coal is unloaded.

[0029] Sub-step S12 is then executed: The system determines the pressure difference in the balancing pipeline between the pulverized coal lock hopper 2 and the pulverized coal feed tank 3. When the pressure difference monitoring device 33 detects a pressure difference of 0.59 MPa, the fluidization valve 19 of the pulverized coal lock hopper 2 is opened to introduce high-pressure carbon dioxide to fluidize the pulverized coal. The purpose of setting this pressure difference condition is to avoid the coal line from fluctuating violently during feeding due to excessive pressure difference between the two tanks, which would affect the gasifier's operating condition. When the balancing pipeline pressure difference meets the condition, or when the fluidization valve 19 is fully open and the second feeding valve 23 is open, the system opens the first feeding valve 22 of the pulverized coal lock hopper 2 to start feeding the pulverized coal feed tank 3. If the pressure monitoring device 30 shows that the pressure of the pulverized coal lock hopper 2 is higher than the pressure of the pulverized coal feed tank 3 by more than 1 MPa, the air-charging cone pressure valve 21 is opened first, and the first feeding valve is opened after a 5-second delay to avoid excessive pressure difference causing the coal line to fluctuate and trip.

[0030] Next, sub-step S13 is executed: 5 seconds after the first feed valve opens, the system closes the fluidization valve 19 to prevent excessive gas flow from affecting the smooth feeding process. Simultaneously, the coal feeding clock in the pulverized coal feed tank 3 is started for 5 minutes. Subsequently, the system opens the pressurization valve 20 and automatically sets the high-pressure carbon dioxide pressurization flow regulating valve 25 to 40 Nm³. 3 / h, set the pressure differential regulating valve 38 to 350kPa to control the fluidizing gas volume and thus accurately control the rate at which pulverized coal is conveyed to the pulverized coal feed tank 3.

[0031] Then, sub-step S14 is executed: when the 30-second timer expires or the first low-level monitoring device 29 of the pulverized coal lock hopper 2 shows a low-level signal, the system closes the pressurization valve 20 and switches the high-pressure carbon dioxide pressurization flow regulating valve 25 and the pressurization flow differential pressure regulating valve 38 to manual mode and closes them. This indicates that the feeding of pulverized coal lock hopper 2 to pulverized coal feed tank 3 has ended.

[0032] Finally, sub-step S15 is executed: After the material feeding is completed, the system makes a judgment based on the actual situation: If the valve position is confirmed and a low material level signal appears in the pulverized coal lock hopper 2, and the coal feeding time has expired or there has been a manual overshoot, then the system proceeds normally to step S2; if the coal feeding time has not yet ended but the low material level signal has already been triggered, or if the low material level signal never appears, that is, the second low material level monitoring device 32 also does not show a high material level signal, then it indicates that pulverized coal bridging has occurred in the pulverized coal lock hopper 2, and the system switches to the anti-bridging subroutine for processing. The anti-bridging subroutine specifically includes the following steps: Sub-step S101: First, open the pressurization valve 20 and the fluidization valve 19 to introduce high-pressure carbon dioxide to fluidize the pulverized coal and eliminate bridging.

[0033] Sub-step S102: After confirming that the fluidization valve 19 is closed and the valve position feedback is normal, close the first feed valve 22 and the second balance valve 18 to isolate the pulverized coal lock hopper 2 from the pulverized coal feed tank 3.

[0034] Sub-step S103: Subsequently, after confirming that the above valve closure feedback is normal, and after the anti-bridging pressure differential monitoring device 36 detects that the pressure difference between the pulverized coal lock hopper 2 and the pulverized coal feed tank 3 reaches 150 kPa, the first discharge valve 22 is opened, the fluidization valve 19 is closed after a delay of 5 seconds, and the second balancing valve 18 is opened after a further delay of 20 seconds, using the pressure difference between the two tanks as the power source for eliminating bridging.

[0035] Sub-step S104: If the first low material level monitoring device 29 detects a low material level signal in the pulverized coal lock hopper 2, then sub-step S105 is executed; if the low material level signal still does not appear, then the bridge is reset, and after 2 seconds, the process returns to sub-step S101 to try again.

[0036] Sub-step S105: Close the first discharge valve 22 and the air cone pressurization valve 21, and return to step S2 to continue the normal process.

[0037] Sub-step S106: In addition, the operator can perform a override operation as needed, closing the air cone pressurization valve 21, and after a 5-second delay, closing the first discharge valve 22, and directly returning to step S2. After successful bridge elimination, the system jumps to step S2 of coal feeding sequence control to continue executing subsequent operations.

[0038] Step S2: High-voltage side isolation and pressure relief After entering the high-pressure isolation and depressurization stage, when the pressure monitoring device 30 displays a pressure of 4.97 MPa or the air-filling cone pressure valve 21 is open, and the fluidizing valve 19 is closed, the first discharge valve 22 is open, and the pressure valve 20 is confirmed to be closed, the DCS controller first resets the coal feeding time, closes the air-filling cone pressure valve 21, sets the opening of the coal pulverized hopper air-filling cone regulating valve 26 to 0%, and closes the first discharge valve 22 after a 5-second delay, thus beginning the isolation of the pulverized coal hopper 2. After valve position confirmation, the system closes the second discharge valve 23 and the first balance valve 17 and the second balance valve 18 between the pulverized coal hopper 2 and the pulverized coal feed tank 3, completing the complete isolation of the pulverized coal hopper 2 from the high-pressure side equipment.

[0039] After isolation is completed, perform multi-stage step-by-step depressurization: Sub-step S21: First, open the first pressure relief valve 13 of the pulverized coal lock hopper 2 to start pressure relief. After the pressure monitoring device 30 shows that the pressure of the pulverized coal lock hopper has dropped to 2.0 MPa, close the valve.

[0040] Sub-step S22: Then, open the second pressure relief valve 9 to continue depressurizing. When the pressure monitoring device 30 shows that the pressure of the pulverized coal lock hopper has dropped to 0.25 MPa and the pressure difference monitoring device 37 detects that the pressure difference between the pulverized coal lock hopper 2 and the pulverized coal storage silo 1 is less than 0.15 MPa, open the third pressure relief valve 12 and the fourth pressure relief valve 11 to ensure that the pressure between the pulverized coal storage silo 1 and the pulverized coal lock hopper 2 reaches a balanced state. At this point, the depressurization is completed.

[0041] Step S3: After depressurization is completed, proceed to the low-pressure side charging stage, which specifically includes: Sub-step S31: The DCS controller closes the second pressure relief valve 9 and opens the first fluidization valve 10 of the pulverized coal storage silo 1 to start conveying pulverized coal to the pulverized coal lock hopper 2.

[0042] Sub-step S32: After the valve position is confirmed, the system first opens the second connecting valve 14 between the pulverized coal storage silo 1 and the pulverized coal lock hopper 2 to prevent pulverized coal from accumulating at the valve and causing it to be unable to open later. Then, the first connecting valve 24 is opened, and the first fluidization valve 10 is closed after 10 seconds to avoid the fluidization gas forming a blockage that affects normal feeding. At the same time, the feeding clock of the pulverized coal storage silo 2 is started to start a 5-minute countdown.

[0043] Sub-step S33: When the first high-level monitoring device 28 of the pulverized coal lock hopper 2 displays a high-level signal, or the feeding timer reaches 5 minutes, or the operator intervenes manually, it indicates that the feeding from the pulverized coal storage silo 1 to the pulverized coal lock hopper 2 has ended. The system prioritizes closing the first connecting valve 24 to prevent pulverized coal from clogging the valve. After confirming the valve position, the system records the weighing weight of the pulverized coal storage silo 1, and then closes the second connecting valve 14, the third pressure relief valve 12, and the fourth pressure relief valve 11 to complete the isolation of the pulverized coal lock hopper 2. This step can pause sequential control.

[0044] Step S4: After the material loading and isolation are completed, the pressurization and equalization stage begins, which specifically includes: Sub-step S41: First, after confirming the valve position and that there is no sequential control pause condition, the DCS controller opens the pressurization valve 16 to pressurize the pulverized coal lock hopper 2 and backflush the bag filter 4. After confirming the valve position for 20 seconds, the pressurization valve 20 is opened. After the valve is in position, the high-pressure carbon dioxide pressurization flow regulating valve 25 and the pressurization stage differential pressure regulating valve 39 are switched to automatic mode.

[0045] Sub-step S42: Subsequently, the system performs step-by-step pressurization based on the pressure rise: when the pressure monitoring device 30 displays that the pulverized coal lock hopper pressure reaches 0.9 MPa, the fluidization valve 19 is opened; when the pressure reaches 1.0 MPa, the air-filling cone pressurization valve 21 is opened and the pulverized coal lock hopper air-filling cone regulating valve 26 is switched to automatic; when the pressure difference monitoring device 34 detects that the pressure difference between the pulverized coal lock hopper 2 and the pulverized coal feed tank 3 reaches 0.45 MPa during the pressurization process, the pressurization valve 16 is closed; when the pressure difference reaches 0.25 MPa, the pressurization valve 20 is closed and the high-pressure carbon dioxide pressurization flow regulating valve 25 and the pressurization stage pressure difference regulating valve 39 are switched to manual closure; when the pressure difference drops to 0.02 MPa, the fluidization valve 19 is closed. Through the above step-by-step pressurization strategy, the system uses the pressurization process pressure difference monitoring device 34 to determine the pressurization progress and complete the pressurization step by step.

[0046] Sub-step S43: After confirming the valve position and that the pressure monitoring device 30 shows that the pulverized coal lock hopper pressure is not greater than 1MPa, the system closes the air charging cone pressurization valve 21, opens the pressure fine adjustment valve 15, and puts the fine adjustment differential pressure regulating device 40 into automatic mode, so as to finely adjust and stably control the pressure of the pulverized coal lock hopper 2 at the target value of 4.95MPa.

[0047] Sub-step S44: When the pressure equalization is completed and the differential pressure monitoring device 35 detects that the pressure difference between the pulverized coal lock hopper 2 and the pulverized coal feed tank 3 is maintained within the range of ±0.01MPa for 10 seconds, it indicates that the pressure difference between the two tanks has stabilized and the feeding conditions are mature. The system closes the pressure fine adjustment valve 15 and switches the fine adjustment differential pressure regulating device 40 to manual closing. After the valve is closed, the first balance valve 17 and the second balance valve 18 are opened to equalize the pressure in the two tanks, making full preparations for the smooth addition of coal to the pulverized coal feed tank in the next cycle.

[0048] Step S5: After pressure equalization is completed, the cycle of waiting and stopping begins, specifically including: Sub-step S51: After valve position confirmation, the system checks whether there is a stop signal in the sequential control program; if there is no stop signal, the sequential control program enters the standby waiting state, waiting for the second low material level monitoring device 32 of the pulverized coal feed tank 3 to show a low material level signal again or for the operator to manually release the material, and automatically returns to step S1 to start the next cycle.

[0049] Sub-step S52: If there is a stop signal, the system first stops the rotating feeder 6, then stops the screw conveyor 7 after 30 seconds, and then returns to the sequential control initialization state. The program can be restarted by the operator pressing the start switch again.

[0050] This embodiment achieved the following operational results on the Shell gasification unit of Jinxin Chemical: the controlled coal feeding cycle time was reduced from 25 minutes before the modification to 20 minutes, shortening the single coal feeding cycle by about 20%, significantly improving the coal powder conveying efficiency. The pressure control accuracy of the pulverized coal lock hopper was greatly improved. Through stepped pressurization and automatic adjustment by the pressure fine-tuning valve 15, the final pressure of the pulverized coal lock hopper can be stably controlled within the range of 4.95MPa±0.05MPa, and the pressure fluctuation amplitude is reduced by about 70% compared with manual control. The failure rate of the rotary feeder 6 and the screw conveyor 7 was significantly reduced, and the equipment operating rate increased from 92% before the modification to over 98%. The failure cycle of the control valves related to the coal lock system was extended, and the service life of the valves was extended by about 40% compared with before the modification, effectively reducing equipment maintenance costs and shutdown risks. The gasifier shutdown accident caused by insufficient coal due to pulverized coal bridging was completely eliminated. Since the system was put into operation, there has not been a single unplanned shutdown of the gasifier due to pulverized coal conveying problems. The workload of DCS master controllers has been significantly reduced, freeing them from frequent manual adjustments and allowing them to focus more on monitoring and maintaining other DCS interfaces.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sequential control system for a Shell gasifier pulverized coal pressurization system, characterized in that, It includes a pulverized coal storage silo, a pulverized coal lock hopper, a pulverized coal feeder, a high-pressure inert gas source, a detection unit, a control unit, and an execution unit; The outlet of the pulverized coal storage bin is connected to the inlet of the pulverized coal lock hopper via a first feeding pipeline, and the outlet of the pulverized coal lock hopper is connected to the inlet of the pulverized coal feed tank via a second feeding pipeline; the outlet of the pulverized coal lock hopper is also connected to the inlet of the pulverized coal feed tank via a balancing pipeline, and the outlet of the pulverized coal feed tank is connected to the inlet of the gasifier. The pulverized coal lock hopper is also connected to the inlet of the bag filter via a pressure relief pipeline; the outlet of the high-pressure inert gas source is connected to the pressurization port at the top of the pulverized coal lock hopper via a pressurization pipeline. The detection unit includes a weighing monitoring device installed on the pulverized coal storage silo, a first high-level monitoring device and a first low-level monitoring device installed on the pulverized coal lock hopper, a pressure monitoring device installed on the pulverized coal lock hopper, a second high-level monitoring device and a second low-level monitoring device installed on the pulverized coal feed hopper, a discharge pressure differential monitoring device installed on the balance pipeline, a pressurization process pressure differential monitoring device, a pressure equalization completion pressure differential monitoring device and a bridging elimination pressure differential monitoring device, and a pressure relief pressure differential monitoring device installed between the pulverized coal lock hopper and the pulverized coal storage silo. The execution unit includes a first connecting valve and a second connecting valve disposed on the first discharge pipeline, a pressure fine adjustment valve disposed on the first discharge pipeline between the first connecting valve and the second connecting valve, a first discharge valve and a second discharge valve disposed on the second discharge pipeline, a first balancing valve and a second balancing valve disposed on the balancing pipeline, a first pressure relief valve, a second pressure relief valve, a third pressure relief valve and a fourth pressure relief valve disposed on the pressure relief pipeline, and a pressure charging valve, a high-pressure carbon dioxide pressure charging flow regulating valve and a pressure charging flow differential pressure regulating valve disposed on the pressure charging pipeline. The signal output terminals of each monitoring device in the detection unit are connected to the signal input terminals of the control unit, and the signal output terminals of the control unit are connected to the signal input terminals of each execution device in the execution unit.

2. The sequential control system for a Shell gasifier pulverized coal pressurization system according to claim 1, characterized in that, The pulverized coal lock hopper is also connected to an air-filled whistle fluidization pipeline, which is equipped with a fluidization valve and is connected to the high-pressure carbon dioxide gas source. The pulverized coal lock hopper is also connected to an air-filled cone pressurization pipeline, which is equipped with an air-filled cone pressurization valve and a pulverized coal lock hopper air-filled cone regulating valve and is connected to the high-pressure carbon dioxide gas source. The pulverized coal storage silo is connected to a low-pressure nitrogen gas flow fluidization pipeline, which is equipped with a first fluidization valve and a second fluidization valve and is connected to a low-pressure nitrogen gas source.

3. The sequential control system for a Shell gasifier pulverized coal pressurization system according to claim 1, characterized in that, The pulverized coal lock hopper is also connected to a pressurization and backflushing pipeline, which is equipped with a pressurization valve and is also connected to a high-pressure gas pipeline network.

4. A sequential control method for a Shell gasifier pulverized coal pressurization system, employing the Shell gasifier pulverized coal pressurization system sequential control system as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Feeding Start-up and Discharge Steps: When the pulverized coal feed hopper reaches the low material level, the fluidization operation of the pulverized coal storage bin is executed and the discharge valve of the pulverized coal lock hopper is opened. When the preset differential pressure condition is met, the pulverized coal lock hopper discharges material into the pulverized coal feed hopper. At the same time, the material level signal and timing results are used to determine whether the discharge is completed normally. If bridging abnormality occurs, the process is switched to the anti-bridging subroutine. S2. High-pressure side isolation and depressurization steps: After the material is fed, close the high-pressure side valve connected to the pulverized coal feed tank in sequence to isolate the pulverized coal lock hopper. Then, open the depressurization valve step by step according to the multi-stage step depressurization strategy to release the pressure of the pulverized coal lock hopper to a low-pressure state. S3. Low-pressure side loading procedure: After depressurization, open the connecting valve between the pulverized coal storage bin and the pulverized coal lock hopper to allow the pulverized coal in the pulverized coal storage bin to fall into the pulverized coal lock hopper. Determine whether the loading is complete by weighing and material level monitoring. After completion, close the connecting valve to isolate the pulverized coal lock hopper. S4. Pressurization and equalization steps: Perform multi-stage step pressurization on the pulverized coal lock hopper after it has been loaded. Open the pressurization valves at each stage according to the preset pressure increase conditions. After the pressure of the pulverized coal lock hopper is raised to the target pressure value, open the balance valve between the pulverized coal lock hopper and the pulverized coal feed tank to equalize the pressure of the two tanks. S5. Looping Waiting and Stopping Steps: After pressure equalization, the sequential control program enters the standby waiting state, waiting for the pulverized coal feeder to show a low material level signal again before returning to step S1, or responding to the stop signal to execute the shutdown procedure and return to the initialization state.

5. The sequential control method for a Shell gasifier pulverized coal pressurization system according to claim 4, characterized in that, The S1 feeding start and unloading steps specifically include the following steps: S11. In response to the low material level signal of the pulverized coal feeder, open the second fluidization valve of the pulverized coal storage silo to fluidize the pulverized coal, and open the second discharge valve of the pulverized coal lock hopper. S12. When the pressure difference monitoring device detects that the pressure difference in the balance pipeline reaches 0.59MPa, open the fluidization valve of the pulverized coal lock hopper; when the pressure difference in the balance pipeline meets the conditions or the fluidization valve is fully open and the second discharge valve is open, open the first discharge valve of the pulverized coal lock hopper; if the pressure monitoring device shows that the pressure of the pulverized coal lock hopper is higher than the pressure of the pulverized coal feeder by more than 1MPa, first open the air-filling cone pressurization valve, and then open the first discharge valve after a 5-second delay. S13. Close the fluidization valve 5 seconds after the first feed valve opens; start the coal feeding timer, open the pressurization valve, and set the high-pressure carbon dioxide pressurization flow regulating valve to automatic setting of 40 Nm. 3 / h, set the pressure differential regulating valve for pressurization flow rate to 350kPa; S14. After a 30-second delay or when the first low-level monitoring device detects a low-level signal, close the pressurization valve and manually close the high-pressure carbon dioxide pressurization flow regulating valve and the pressurization flow differential pressure regulating valve. S15. After the material feeding is completed, if the first low material level monitoring device generates a low material level signal and the coal feeding time has expired or the process is manually overridden, proceed to step S2; if the coal feeding time has not expired but the low material level signal is triggered, or the low material level signal does not appear, proceed to the bridge elimination sub-program.

6. The sequential control method for a Shell gasifier pulverized coal pressurization system according to claim 4, characterized in that, The S2 high-voltage side isolation and depressurization steps specifically include the following steps: S21: Open the first pressure relief valve of the pulverized coal lock hopper, and close the first pressure relief valve after the pressure monitoring device shows that the pressure of the pulverized coal lock hopper has dropped to 2.0MPa; S22: Open the second pressure relief valve of the pulverized coal lock hopper. When the pressure monitoring device shows that the pressure of the pulverized coal lock hopper drops to 0.25MPa and the pressure difference monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal storage silo is less than 0.15MPa, open the third and fourth pressure relief valves of the pulverized coal lock hopper to ensure the pressure balance between the pulverized coal storage silo and the pulverized coal lock hopper.

7. The sequential control method for a Shell gasifier pulverized coal pressurization system according to claim 4, characterized in that, The S3 low-pressure side loading step specifically includes the following steps: S31: Close the second pressure relief valve and open the first fluidization valve of the pulverized coal storage silo; S32: After confirming the valve position, first open the second connecting valve between the pulverized coal storage bin and the pulverized coal lock hopper, then open the first connecting valve, and close the first fluidization valve after a 10-second delay, and start the pulverized coal storage bin feeding timer. S33: When the first high material level monitoring device displays a high material level signal, or the feeding timer reaches the preset time, or when manually operated, the first connecting valve is closed first, the weight of the pulverized coal storage bin is recorded, and then the second connecting valve, the third pressure relief valve, and the fourth pressure relief valve are closed to complete the isolation.

8. A sequential control method for a Shell gasifier pulverized coal pressurization system according to claim 4, characterized in that, The S4 step, pressurization and equalization step specifically includes the following steps: S41: Open the pressurization valve to pressurize the pulverized coal lock hopper and backflush the bag filter. After a delay, open the charging valve and put the high-pressure carbon dioxide charging flow regulating valve and the charging stage differential pressure regulating valve into automatic mode. S42: When the pressure monitoring device shows that the pulverized coal lock hopper pressure reaches 0.9MPa, open the fluidization valve; when the pulverized coal lock hopper pressure reaches 1.0MPa, open the air-charging cone pressure valve and put the pulverized coal lock hopper air-charging cone regulating valve into automatic mode; when the pressure difference monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal feed tank reaches 0.45MPa during the pressurization process, close the pressurization valve; when the pressure difference reaches 0.25MPa, close the pressurization valve and put the high-pressure carbon dioxide pressurization flow regulating valve and the pressurization stage pressure difference regulating valve into manual mode; when the pressure difference reaches 0.02MPa, close the fluidization valve. S43: When the pressure monitoring device shows that the pulverized coal lock hopper pressure is not greater than 1MPa, close the air charging cone pressurization valve, open the pressure fine adjustment valve and put the fine adjustment differential pressure regulating device into automatic mode, and adjust the pulverized coal lock hopper pressure to stabilize at 4.95MPa; S44: When the pressure equalization is completed and the differential pressure monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal feeder is maintained between ±0.01MPa for 10 seconds, the pressure fine adjustment valve is closed. After it is closed, the first balance valve and the second balance valve are opened to equalize the pressure of the two tanks.

9. A sequential control method for a Shell gasifier pulverized coal pressurization system according to claim 4, characterized in that, The S5 loop waiting and stopping step specifically includes the following steps: S51: After confirming the valve position, check if there is a stop signal in the sequential control program. If there is no stop signal, the sequential control enters the standby waiting state, waiting for the second low material level monitoring device to detect the low material level of the pulverized coal feeder and trigger it again, and then return to step S1. S52: If a stop signal is received, the rotating feeder will stop, the screw conveyor will stop after a delay, and the system will return to the initialization state.

10. A sequential control method for a Shell gasifier pulverized coal pressurization system according to claim 4, characterized in that, The bridge cancellation subroutine includes the following steps: S101: Open the pressurization valve and fluidization valve to fluidize the pulverized coal and begin eliminating bridging; S102: After confirming that the fluidization valve is closed and the feedback is normal, close the first feed valve and the second balance valve to isolate the pulverized coal lock hopper from the pulverized coal feed tank; S103: After confirming that the first feeding valve, the second balancing valve and the pressurizing valve are closed normally, and after the anti-bridging pressure differential monitoring device detects that the pressure difference between the pulverized coal lock hopper and the pulverized coal feeder reaches 150 kPa, open the first feeding valve, close the fluidization valve after a 5-second delay, and open the second balancing valve after a 20-second delay, using the pressure difference as the power to eliminate bridging. S104: When the first low material level monitoring device detects a low material level signal in the pulverized coal lock hopper, execute step S105; if the low material level signal in the pulverized coal lock hopper does not appear, reset the bridge elimination mechanism and return to step S101. S105: After executing step S104, close the first discharge valve, close the air cone pressurization valve, and return to step S2; S106: The operator performs overdrive as needed, closes the air cone pressurization valve, and closes the first discharge valve after a 5-second delay, returning to step S2.

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