Urea hydrolyzer system automatic switching method and device

Abstract

The invention provides an automatic switching method and device for a urea hydrolyzer system, and the method comprises the steps: scanning equipment state parameters and valve position states of parallel urea hydrolyzers in real time based on a program controller, and generating a switching permission signal through logic and operation; an outlet adjusting valve of the standby hydrolyzer is put into an automatic control mode, and a pressure reference value of the standby hydrolyzer is set according to the current looped network pressure so as to realize stable injection of ammonia gas mixed gas; gradually closing an outlet regulating valve of the original operating hydrolyzer at a preset linear closing rate, and controlling the opening change of the outlet regulating valve in a manual mode to maintain the pressure stability of the looped network; and providing a manual confirmation interface for an operator, and triggering an isolation process of the original operation equipment and completing switching after confirming that the pressure of the looped network is stable based on DCS picture parameters. The full-process automatic switching of the urea hydrolyzer system is realized, the operation safety and reliability are improved, the switching time is shortened, the ring network pressure fluctuation in the switching process is effectively controlled, and the continuity and stability of ammonia gas supply of the denitration system are ensured.

Description

Technical Field

[0001] This invention belongs to the field of control technology, specifically relating to an automatic switching method and device for a urea hydrolyzer system. Background Technology

[0002] As the core ammonia supply equipment in the SCR denitrification system of thermal power plants, the parallel operation control technology of urea hydrolyzers directly affects the unit's environmental protection indicators and system stability. In existing technologies, the switching control of urea hydrolyzers mainly focuses on the start-up and shutdown optimization of individual units, primarily concerned with the temperature and pressure control of the hydrolyzer itself. For switching between parallel systems, only general recommendations are offered from an operation management perspective, such as "standby equipment should be put into operation first, then the original operating equipment should be shut down," but no specific, programmable automatic control logic, step sequences, or interlocking conditions are disclosed. In actual projects, switching operations rely entirely on operators manually operating multiple valves and regulators according to procedures, including confirming equipment status, manually opening and closing valves one by one, and adjusting pressure. The entire process is time-consuming and requires a high level of operator proficiency.

[0003] In large industrial installations such as thermal power plants, urea hydrolyzers operating in parallel face a series of technical bottlenecks when switching between them, due to the reliance on manual, step-by-step operation by personnel: Operational reliability issues: The manual switching operation of the urea hydrolyzer involves many steps, including confirming the status of multiple valves, switching modes, and adjusting the opening degree. With the increasing number of peak-shaving operations, operators are prone to omissions or misoperations during close operation, which may lead to interruption of ammonia supply or pressure fluctuations, directly affecting the unit's denitrification efficiency and environmental protection indicators.

[0004] Switching efficiency and response speed issues: From the judgment condition to the completion of the switch, the manual process and the waiting process take several minutes or even longer, which cannot meet the demand for rapid and smooth adjustment of ammonia supply when the unit load changes rapidly.

[0005] System stability and safety issues: During the switching process, if the outlet pressure of the two hydrolyzers is not properly controlled, it may cause violent fluctuations in the outlet ring network pressure, affecting the hydrolyzers that were originally operating normally, and even impacting the downstream SCR denitrification system.

[0006] Human resources and standardization issues: It relies heavily on the experience and sense of responsibility of operators. Differences in the operating habits and speeds of different personnel may lead to unstable switching effects, and there is a lack of standardized and procedural execution processes. Summary of the Invention

[0007] The present invention aims to at least partially solve one of the technical problems in the related art.

[0008] Therefore, the first objective of this invention is to provide an automatic switching method for a urea hydrolyzer system.

[0009] The second objective of this invention is to provide an automatic switching device for a urea hydrolyzer system.

[0010] The third objective of this invention is to provide a computer device.

[0011] A fourth objective of this invention is to provide a non-transitory computer-readable storage medium.

[0012] To achieve the above objectives, a first aspect of the present invention provides an automatic switching method for a urea hydrolyzer system, comprising: S1, based on the real-time scanning of the equipment status parameters and valve position status of the parallel urea hydrolyzer by the program controller, generates a switching permission signal through logical AND operation; S2, put the standby hydrolyzer outlet regulating valve into automatic control mode, and set its pressure reference value according to the current ring network pressure to achieve stable injection of ammonia gas mixture. S3 gradually closes the outlet regulating valve of the original hydrolyzer at a preset linear closing rate, while controlling its opening change in manual mode to maintain stable ring network pressure. S4 provides a manual confirmation interface to operators. After confirming that the ring network pressure is stable based on the DCS screen parameters, it triggers the isolation process of the original operating equipment and completes the switchover.

[0013] In one embodiment of the present invention, S1 includes: S11 verifies the standby hydrolyzer's ammonia injection status signal, outlet isolation valve, outlet ring network isolation valve, fully open status of the outlet valve, and fully closed status of the outlet regulating valve through logical AND operation. S12, when any verification condition is not met, the current step number is maintained through the HOLD module until all conditions are met, and then the step number is incremented.

[0014] In one embodiment of the present invention, S2 includes: S21, set the pressure setting value of the outlet regulating valve to the current ring network pressure value; S22, the MASTERSEQ algorithm is used to monitor the change in valve opening in real time. When the valve opening reaches the preset target value, the step increment is triggered.

[0015] In one embodiment of the present invention, S3 further includes: S31, gradually close the original operating hydrolyzer outlet regulating valve at a preset slow linear rate; S32 uses the DEVICESEQ algorithm to collect the actual opening value of the control valve in real time. When the deviation between the actual opening and the target opening exceeds 5%, a timeout alarm is triggered.

[0016] In one embodiment of the present invention, S4 further includes: S41 displays the ring network pressure fluctuation amplitude in real time through the DCS screen; S42: When the ring network pressure fluctuation does not exceed the set threshold for 30 consecutive seconds, the operator is allowed to click the manual confirmation button to trigger the subsequent isolation process.

[0017] In one embodiment of the present invention, the method further includes: S5, through the main controller, simultaneously adjusts the opening changes of the outlet regulating valves of #1 and #2 hydrolyzers, so that the #1 regulating valve is closed proportionally and the #2 regulating valve is opened proportionally, so as to maintain a constant total ammonia flow rate in the ring network. S6, the main controller dynamically adjusts the valve opening ratio according to the real-time ammonia demand to ensure that the total flow deviation does not exceed 10% during the switching process.

[0018] To achieve the above objectives, a second aspect of the present invention provides an automatic switching device for a urea hydrolyzer system, comprising: The status scanning and logic verification module scans the equipment status parameters and valve position status of the parallel urea hydrolyzer in real time based on the program controller, and generates a switching permission signal through logical AND operation. The automatic control and pressure reference setting module for the regulating valve puts the standby hydrolyzer outlet regulating valve into automatic control mode and sets its pressure reference value according to the current ring network pressure to achieve stable injection of ammonia gas mixture. The linear closing and manual adjustment module of the regulating valve gradually closes the original operating hydrolyzer outlet regulating valve at a preset linear closing rate, while controlling its opening change through manual mode to maintain the stability of the ring network pressure. The manual confirmation and isolation process triggering module provides operators with a manual confirmation interface. After confirming that the ring network pressure is stable based on the DCS screen parameters, it triggers the isolation process of the original operating equipment and completes the switchover.

[0019] An automatic switching method and apparatus for a urea hydrolyzer system according to an embodiment of the present invention has the following beneficial effects: Enhancing operational reliability and safety: Through strict interlocking conditions and procedural steps, human error is completely eliminated, minimizing safety risks during the switching process. Significantly improving switching efficiency: The original manual operation and redundant waiting time caused by human error are reduced to an automated process of less than one minute, achieving "one-click switching," greatly improving emergency response speed and operational efficiency. Ensuring a smooth system transition: Through the core strategy of "start first, then stop" combined with valve rate control, a smooth and uninterrupted switching of the ammonia supply source is achieved, effectively avoiding fluctuations in ring network pressure and ensuring the stable operation of the denitrification system and the unit. Promoting standardized and intelligent operation: Transforming personal experience into standardized procedures lowers the operational threshold and is an important practice for realizing intelligent and minimally staffed operation of power plants.

[0020] To achieve the above objectives, a third aspect of this application provides a computer device, including a processor and a memory; wherein the processor runs a program corresponding to the executable program code stored in the memory, for implementing an automatic switching method for a urea hydrolyzer system as described in the first aspect embodiment.

[0021] To achieve the above objectives, a fourth aspect of this application provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements an automatic switching method for a urea hydrolyzer system as described in the first aspect embodiment.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of an automatic switching method for a urea hydrolyzer system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the status monitoring and process management module according to an embodiment of the present invention; Figure 3 This is a flowchart of the automatic switching procedure for a urea hydrolyzer system according to an embodiment of the present invention; Figure 4 This is a flowchart of the automatic switching sequence of the urea hydrolyzer system according to an embodiment of the present invention; Figure 5 This is a logic diagram for automatically switching allowable conditions in a urea hydrolyzer system according to an embodiment of the present invention; Figure 6This is a sequence logic diagram of the automatic switching process management of the urea hydrolyzer system according to an embodiment of the present invention; Figure 7 This is a logic diagram of the automatic switching valve control for a urea hydrolyzer system according to an embodiment of the present invention; Figure 8 This is a logic diagram for automatic switching status monitoring of a urea hydrolyzer system according to an embodiment of the present invention; Figure 9 This is an overview screen diagram of the urea hydrolyzer control system according to an embodiment of the present invention; Figure 10 This is a screenshot of the automatic switching to manual confirmation screen of the urea hydrolyzer system according to an embodiment of the present invention; Figure 11 This is a structural diagram of an automatic switching device for a urea hydrolyzer system according to an embodiment of the present invention; Figure 12 It is a computer device according to an embodiment of the present invention. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. 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 should fall within the scope of protection of the present invention.

[0026] The following description, with reference to the accompanying drawings, describes an automatic switching method and apparatus for a urea hydrolyzer system according to an embodiment of the present invention.

[0027] Example 1 Figure 1 This is a flowchart of an automatic switching method for a urea hydrolyzer system according to an embodiment of the present invention, such as... Figure 1 As shown, it includes: S1, based on the real-time scanning of the equipment status parameters and valve position status of the parallel urea hydrolyzer by the program controller, generates a switching permission signal through logical AND operation.

[0028] In some implementations, the programmable controller (PCC) periodically polls to collect operating status parameters of the parallel urea hydrolyzers, including body pressure, temperature, and liquid level, while simultaneously reading the on / off status signals of key valves. For example, for the standby hydrolyzer #2, the system needs to confirm in real time whether its outlet isolation valve (J0HSJ62AA019), outlet ring network isolation valve (J0HSJ60AA002), and outlet valve (J0HSJ62AA055) are fully open, and whether the outlet regulating valve (J0HSJ62AA102) is fully closed. These status signals are connected to the DCS system via hardwiring or bus communication (such as Modbus, PROFIBUS, Ethernet / IP), with a sampling period typically set to 100ms to ensure the real-time nature and accuracy of the status information.

[0029] Specifically, the system uses a logical AND operation to comprehensively evaluate the above conditions. Only when all conditions are met simultaneously will the system generate an "Allow Switch Signal," which serves as a prerequisite for initiating the subsequent switching process. For example, if any valve is not in the specified position (such as the outlet control valve not being fully closed), the logical AND operation result will be 0, and the switching process will be blocked to prevent the switching operation from being performed under unsafe conditions.

[0030] Furthermore, the valve position status involved in this step must be either fully open or fully closed, and the error range should be controlled within [specific parameters]. Within a certain range, it must meet the common standards for valve positioning accuracy in industrial control (such as ISA-51.1). Simultaneously, the operating parameters of the hydrolyzer body must meet the preset "ready to inject ammonia" conditions, including liquid level. ,temperature ,pressure This ensures that the plant has a stable ammonia supply capacity.

[0031] Furthermore, S1 includes: S11 verifies the "ready to spray ammonia" status signal of the standby hydrolyzer, the fully open status of the outlet isolation valve, the outlet ring network isolation valve, the outlet valve, and the fully closed status of the outlet regulating valve through logical AND operation.

[0032] In some implementations, the "Switching Permission Condition Judgment Module" of this invention performs real-time verification of multiple key status signals of the standby hydrolyzer through logical AND operations to ensure the safety and feasibility of the switching operation. This module is built on the Ovation 3.6.0 control platform and employs logical judgment algorithms from a distributed control system (DCS) to synchronously detect the following: the "Ready to Inject Ammonia" status signal; the fully open status of the outlet isolation valve (J0HSJ62AA019), the outlet ring network isolation valve (J0HSJ60AA002), and the outlet valve (J0HSJ62AA055); and the fully closed status of the outlet regulating valve (J0HSJ62AA102).

[0033] Specifically, this module performs an AND operation on the aforementioned signals using Boolean logic. That is, the system will only set the "switch allowed" signal when all signals meet preset conditions. Specifically, the "ready to inject ammonia" status signal is typically fed back to the DCS by sensors on the hydrolyzer body, such as temperature, pressure, and liquid level. When it is within the set acceptable range, this signal is set to TRUE. Simultaneously, the status signals of each valve are acquired in real time through position feedback devices (such as limit switches or position transmitters of electric actuators). Their opening values ​​must meet the threshold requirements of 100% open or 0% closed, with the error range typically controlled within a certain range. Within a certain range, in order to meet the general standards for valve positioning accuracy in industrial control.

[0034] S12, when any verification condition is not met, the current step number is maintained through the HOLD module until all conditions are met, and then the step number is incremented.

[0035] In some implementations, the HOLD module is embedded in the MASTERSEQ algorithm to control the sequential progression of the switching process. In each step, the system uses the DEVICESEQ algorithm to collect and determine the status signals of the relevant devices in real time, including Boolean status bits such as READY, SUCCESS, and FAILED. If the READY bit is 0 or the FAILED bit is 1 in the current step, the HOLD module will output a logic 1, keeping the MASTERSEQ algorithm at the current step number and preventing automatic incrementing to the next step. Only when the SUCCESS bit becomes 1, indicating that the step has been successfully executed, and the HOLD module outputs 0, will the system proceed to the next step.

[0036] Specifically, the HOLD module's judgment criteria include, but are not limited to, the logical value (0 or 1) of the device status signal, a preset timeout threshold (e.g., failure is determined if the operation is not completed within 60 seconds), and the feedback accuracy of the device control command (e.g., valve opening error is less than...). In addition, the system is equipped with an internal fault timer to monitor the execution time of the equipment. When the accumulated time of the timer exceeds the set threshold, the system will trigger an alarm and pause the process, waiting for manual intervention.

[0037] S2, put the standby hydrolyzer outlet regulating valve into automatic control mode, and set its pressure reference value according to the current ring network pressure to achieve stable injection of ammonia gas mixture.

[0038] In some implementations, the control valve is initially in "manual" mode with an opening of 0%. When a switching command is triggered and the switching permission module confirms that all preconditions are met, the system automatically switches the control valve to "automatic" control mode via the Ovation 3.6.0 platform's control logic. At this time, the control valve's setpoint is set to the current ring network pressure value (e.g., ...). The pressure signal of the ring network is acquired in real time through a pressure transmitter. This is compared with the set value of the regulating valve to form a control deviation. .

[0039] Furthermore, the control valve employs a PID control strategy, and its control output... It consists of three parts: proportion, integral, and differential, and its expression is:

[0040] in, , , These are the proportional, integral, and derivative gain coefficients, which are tuned according to the dynamic response characteristics of the system to ensure a balance between the smoothness of the valve opening change and the response speed.

[0041] Furthermore, S2 includes: S21, set the pressure setting value of the outlet regulating valve to the current ring network pressure value.

[0042] In some implementations, the control valve is a pneumatic control valve, whose control signal is a 4-20mA current signal output from the DCS driving the actuator to achieve continuous valve position adjustment. When the switching program starts, the system first acquires the current ring network pressure value in real time through a pressure transmitter (such as J0HSJ60AA001), and inputs this value as the setpoint of the outlet control valve into the PID controller. The PID controller automatically adjusts the valve opening based on the deviation between the current outlet pressure and the setpoint, gradually approaching and stabilizing the outlet pressure at 0.3MPa. The setting of this setpoint must meet the specifications for control setpoint input in the IEC 61131-3 standard to ensure the accuracy and consistency of the control signal response.

[0043] Specifically, the setpoint accuracy of the regulating valve should reach ±0.01 MPa, and the response time should not exceed 2 seconds to ensure a rapid system response during the initial switching phase. Simultaneously, the rate of change of the regulating valve's opening should be controlled within a reasonable range to avoid sudden changes in ring network pressure due to excessively rapid valve opening. In this invention, the regulating valve is initially set to a fully closed state. After the setpoint is the current ring network pressure, its opening is gradually adjusted by the controller based on pressure feedback to achieve smooth injection.

[0044] S22, the MASTERSEQ algorithm is used to monitor the change in valve opening in real time. When the valve opening reaches the preset target value, the step increment is triggered.

[0045] In some implementations, the MASTERSEQ algorithm serves as the core module of the process control, responsible for managing the sequential execution of the entire switching process. The system divides the switching process into several steps, each corresponding to specific control actions and equipment status requirements. The current step number is stored in the STEP output. The system determines whether the progression condition is met by scanning the READY, SUCCESS, and FAILED bits of each step in real time. When the READY bit of a step is 1 and the SUCCESS bit is 1, the algorithm automatically increments to the next step number; if the READY bit is 0 or the FAILED bit is 1, the HOLD module outputs 1, and the system pauses at the current step until the fault is cleared or manual intervention is required.

[0046] Specifically, this step focuses on the real-time changes in the valve opening. For example, the system sets the #2 hydrolyzer outlet valve (J0HSJ62AA102) to "automatic" mode and sets its pressure setpoint to the current loop pressure (0.3 MPa). The valve gradually adjusts its opening according to the PID control logic, and the system continuously monitors its actual opening value through a closed-loop control loop with a sampling frequency of 100 ms. When the valve opening reaches the target value (such as 100% or the set minimum effective opening), the SUCCESS bit is set, triggering the MASTERSEQ algorithm to proceed to the next step.

[0047] S3 gradually closes the outlet regulating valve of the original hydrolyzer at a preset linear closing rate, while controlling its opening degree change in manual mode to maintain the stability of the ring network pressure.

[0048] Specifically, in some implementations, the original operating hydrolyzer outlet control valve (such as J0HSJ61AA102) is first switched to "manual" control mode after the switching command is triggered to avoid interference from the automatic control logic on the current opening degree. Subsequently, the system gradually reduces the valve opening at a rate of 0.008% per second according to a preset linear closing rate until it is completely closed (i.e., the opening degree is 0%). This rate setting is based on actual operating experience and the dynamic response characteristics of the system, ensuring that it does not cause drastic fluctuations in the ring network pressure during the closing process, thereby avoiding impact on the SCR denitrification system.

[0049] Furthermore, in this step, the valve opening change is controlled collaboratively by the MASTERSEQ and DEVICESEQ algorithms. MASTERSEQ is responsible for advancing the switching process according to a preset sequence, while DEVICESEQ is responsible for monitoring the valve's execution status, including the deviation between the actual opening and the target opening, and whether the execution time exceeds the limit. If an abnormality occurs during the closing process (such as execution timeout or the opening not reaching the command value), the system will automatically pause the switching process and trigger an alarm signal to prompt the operator to intervene.

[0050] Furthermore, S3 includes: S31, gradually closes the outlet regulating valve of the original hydrolyzer at a preset slow linear rate.

[0051] Specifically, this step is executed by the Program Controller in the Ovation 3.6.0 control platform. Through preset control logic, the valve opening command is decreased at a rate of 0.008% per second. This rate is set based on the system's dynamic response characteristics and the requirement for continuous ammonia supply, ensuring that no sudden changes in valve opening during switching will cause ring network pressure fluctuations. For example, if the current valve opening is 100%, the time required to complete the closure is... This window, approximately 3.5 hours, provides the system with ample buffer time to maintain stable operation of the denitrification system.

[0052] S32 uses the DEVICESEQ algorithm to collect the actual opening value of the control valve in real time. When the deviation between the actual opening and the target opening exceeds 5%, a timeout alarm is triggered.

[0053] In some implementations, the DEVICESEQ algorithm establishes a communication connection with the field valve controller (such as J0HSJ62AA102) to read its current opening feedback value in real time and compare it with the preset target opening value. The algorithm is internally configured with a fault timer to record the time from receiving a control command to the actual completion of the response. When the deviation between the actual opening value and the target value exceeds 5% and the duration exceeds a preset threshold (such as 30 seconds), the timer triggers an overtime alarm signal. The system will then pause the current switching step and return control to the operator for intervention.

[0054] Specifically, the key threshold of this alarm mechanism is a 5% opening deviation. This value is set based on actual engineering experience to ensure timely identification and action in abnormal situations such as delayed valve response or actuator jamming. Furthermore, parameters such as alarm response time, timer accuracy, and feedback sampling frequency must all meet industrial control standards such as IEC 61131-3 or ISA-88 / 95 to guarantee the real-time performance and reliability of the system response.

[0055] S4 provides a manual confirmation interface to operators. After confirming that the ring network pressure is stable based on the DCS screen parameters, it triggers the isolation process of the original operating equipment and completes the switchover.

[0056] In some implementations, this manual verification interface is built using the screen configuration function of the DCS system, typically integrated into the main control screen or dedicated switching operation screen of the urea hydrolyzer system. Key parameters displayed on the interface include ring network pressure, the opening degree of the outlet regulating valves of hydrolyzers #1 and #2, ammonia flow rate, and system operating status indicators. Operators determine whether the system has achieved a smooth transition by observing the trends in these parameters. For example, the ring network pressure needs to stabilize at the set value. Nearby, the fluctuation range does not exceed And the duration is not less than Only when it is stable can it be considered stable.

[0057] Furthermore, the interface includes a "Manual Confirmation" button, whose signal triggers the STEP03 state transition in the MASTERSEQ algorithm via DCS logic. Upon receiving the confirmation signal, the system enters the STEP04-STEP08 isolation process, sequentially closing the steam inlet valve, urea solution inlet valve, and outlet isolation valve of the previously operating equipment (such as #1 hydrolyzer), thus completing physical isolation. During this process, the closing sequence and time intervals of each valve are controlled by a preset DEVICESEQ algorithm to ensure the timing and safety of the operation.

[0058] Furthermore, S4 includes: S41 displays the ring network pressure fluctuation amplitude in real time through the DCS screen.

[0059] In some implementations, this step relies on real-time sampling and data processing by the pressure transmitter in the DCS system. The system uses a PID control loop to acquire the ring network pressure signal, with a sampling frequency set to 100ms / time to ensure the real-time and continuous nature of the data. The acquired pressure data is transmitted to the Human-Machine Interface (HMI) via the Ovation platform's OPC interface and displayed on the DCS screen using a combination of trend charts and numeric displays. The trend chart has a 10-minute time window and 600 sampling points to ensure continuous tracking of pressure changes; the numeric display uses a dynamic refresh mechanism with a refresh cycle of 1 second to ensure that operators can obtain the current pressure value in a timely manner.

[0060] Specifically, the system is set to display the ring network pressure fluctuation range with an accuracy of ±0.01 MPa. That is, when the pressure value fluctuates within ±0.01 MPa of the set value, the system determines it to be in a "stable state"; otherwise, an alarm is triggered. This accuracy requirement complies with the control standards for ammonia supply pressure in the denitrification system of thermal power plants (such as GB / T 31821-2015 "Technical Specifications for Operation and Maintenance of Denitrification Systems in Thermal Power Plants"), ensuring a smooth transition of outlet pressure during system switching.

[0061] S42: When the ring network pressure fluctuation does not exceed the set threshold for 30 consecutive seconds, the operator is allowed to click the "Manual Confirmation" button to trigger the subsequent isolation process.

[0062] In the programmed switching execution module of this invention, manual final confirmation is a crucial human-machine interaction step. Its technical implementation principle is based on the design concept of "safety interlocking + human-machine collaboration" in industrial control systems. This step involves setting a "manual confirmation" button on the DCS (Distributed Control System) interface, allowing the operator to determine whether the system has reached a stable state after the system has completed automatic operation, based on real-time monitoring parameters (such as ring network pressure, ammonia flow rate, valve opening, etc.), thereby deciding whether to continue executing subsequent isolation procedures.

[0063] Specifically, after the system completes the automatic operation, it will return control to the operator and display a confirmation prompt window on the DCS screen (e.g., ...). Figure 10As shown in the image, the operator is prompted to click the "Manual Confirmation" button. At this point, the system enters a waiting state, pausing the execution of subsequent processes until operator confirmation or a timeout occurs. The triggering logic of this button is tightly integrated with the HOLD module in the MASTERSEQ algorithm. When the operator clicks confirmation, the system resets the HOLD signal, allowing the process to proceed to the next step and initiating isolation operations on the original operating equipment.

[0064] Furthermore, the confirmation window for this step is typically set to 30 seconds. If no manual confirmation is triggered within this timeframe, the system will automatically determine it as "confirmation failed" and enter an alarm state. This time window is set based on the average response time of operators in emergency situations (approximately 10-20 seconds) and system safety redundancy considerations. This ensures that the system will not blindly proceed if the operator does not respond in a timely manner, thereby avoiding abnormal fluctuations in ring network pressure caused by misoperation or system misjudgment.

[0065] S5, through the main controller, simultaneously adjusts the opening changes of the outlet regulating valves of #1 and #2 hydrolyzers, so that the #1 regulating valve is closed proportionally and the #2 regulating valve is opened proportionally, so as to maintain a constant total ammonia flow rate in the ring network.

[0066] Specifically, the main controller first puts the #2 hydrolyzer outlet control valve (J0HSJ62AA102) into "automatic" control mode and sets its pressure setpoint to the current ring network pressure (0.3 MPa), allowing the valve to automatically adjust its opening based on system feedback, gradually injecting ammonia gas mixture into the ring network. Subsequently, the main controller switches the #1 hydrolyzer outlet control valve (J0HSJ61AA102) to "manual" mode, and operates it at a preset, linearly varying rate. Gradually reduce the opening to 0%. This rate has been verified through engineering simulation and on-site debugging, ensuring a continuous ammonia supply while avoiding system pressure fluctuations caused by excessively rapid adjustments.

[0067] In some implementations, the valve opening adjustment accuracy should reach 0.1% or higher, and the response time should not exceed [a certain value]. This ensures the timeliness and accuracy of control actions. Furthermore, the control mode switching of the valve must meet the definition of sequential control logic in the IEC 61131-3 standard to ensure the portability and compatibility of the control logic.

[0068] S6, the main controller dynamically adjusts the valve opening ratio according to the real-time ammonia demand to ensure that the total flow deviation does not exceed 10% during the switching process.

[0069] In some implementations, this step uses closed-loop control logic to collect the total ammonia demand signal in the denitrification system in real time and use it as the set value of the main controller. Combined with the actual opening degree and flow feedback of the outlet regulating valve of the currently operating hydrolyzer (such as #1 hydrolyzer) and the standby hydrolyzer (such as #2 hydrolyzer), proportional adjustment is performed to ensure that the total flow deviation does not exceed 10% during the switching process.

[0070] Specifically, the main controller employs a PID (Proportional-Integral-Derivative) control algorithm. Its input is the difference between the total ammonia demand and the current total flow rate, and its output is the valve opening adjustment command. During the switching process, the #1 hydrolyzer outlet valve... The flow rate of the #1 hydrolyzer is linearly shut off, while the outlet regulating valve of the #2 hydrolyzer gradually opens according to the output of the main controller to compensate for the reduced flow rate of the #1 hydrolyzer. This control strategy is implemented through the MASTERSEQ and DEVICESEQ algorithms configured in the Ovation 3.6.0 control platform, ensuring the orderly execution of each step and real-time feedback of the equipment status.

[0071] Furthermore, the sampling period of the main controller is typically set to... To ensure a rapid response to changes in flow rate, the valve opening range is 0% to 100%, and its response time should be controlled within [timeframe missing]. Within a certain range, to meet the dynamic adjustment requirements during the switching process. The control threshold for flow deviation is set at 10%, meaning that the total flow change during the switching process must not exceed 10% of the current set value. This indicator meets the technical requirements for the continuity of ammonia supply in the denitrification system of thermal power plants.

[0072] An automatic switching method for a urea hydrolyzer system according to an embodiment of the present invention can realize the full-process automatic switching of the urea hydrolyzer system, improve operational safety and reliability, shorten the switching time to within 45 seconds, and effectively control the ring network pressure fluctuation within ±0.005MPa during the switching process, ensuring the continuity and stability of ammonia supply to the denitrification system.

[0073] Example 2 The following describes in detail an automatic switching method for a urea hydrolyzer system according to an embodiment of the present invention, with reference to the accompanying drawings.

[0074] The core of this invention lies in constructing an automatic switching system and method for urea hydrolyzers based on a programmable controller. For example... Figure 9 The diagram shows the control system of the urea hydrolyzer. The system is based on the Ovation 3.6.0 platform and adds a new set of integrated control logic, which integrates the scattered valve operations into an orderly, condition-driven automatic process.

[0075] The complete technical solution includes the following three core modules: 1. Switch the permission condition judgment module (safety interlock layer) Before initiating the automatic switching procedure, the control system automatically performs real-time scanning and logical AND operations on the following key conditions. The "Switching Allow" signal is only set when all conditions are met: Confirm that the standby hydrolyzer (taking #2 hydrolyzer as an example) is in the "ready to inject ammonia" state, indicating that its core parameters such as pressure, temperature, and liquid level are normal.

[0076] Confirm that the outlet pipeline of the standby hydrolyzer is unobstructed: including that its outlet isolation valve (J0HSJ62AA019), outlet ring network isolation valve (J0HSJ60AA002), and outlet valve (J0HSJ62AA055) are all in the fully open position.

[0077] Confirm that the standby hydrolyzer outlet regulating valve (J0HSJ62AA102) is fully closed to ensure that it will not cause disturbance to the operating loop network before it is put into automatic operation.

[0078] The purpose of this module is to fundamentally prevent forced switching when the device status does not meet the requirements, thus forming the safety foundation of this solution.

[0079] 2. Programmatic switching execution module (core control layer) like Figure 3-7 As shown, once the switching command is issued and conditions permit, the control system automatically executes the preset steps: STEP01: Establish a backup power source smoothly. Put the outlet regulating valve of hydrolyzer #2 into "automatic" control mode and set its pressure setpoint to the current ring network pressure (0.3MPa). The valve will automatically and slowly open according to the setpoint, smoothly injecting ammonia gas mixture into the ring network and avoiding pressure surges.

[0080] STEP02: Smoothly Exit the Operating Source. After the #2 hydrolyzer control valve is put into automatic mode and the pressure is set, switch the #1 hydrolyzer outlet control valve (J0HSJ61AA102) to "manual" mode and linearly close it to 0% at a preset, slow rate (0.008% / s). This step is a key innovation. By precisely controlling the closing rate, in conjunction with STEP01, a seamless switch of the ammonia supply source from the #1 hydrolyzer to the #2 hydrolyzer is achieved, ensuring the continuity of ammonia supply to the downstream denitrification system.

[0081] STEP03: Final manual confirmation. For example... Figure 10 As shown, a "Manual Confirmation" button is provided, and the system waits for the operator to confirm, based on the parameters on the DCS screen, that the ring network pressure is stable and the ammonia supply has been successfully switched. This step introduces human-machine interaction at a key node into the automated process, giving the operator final decision-making authority and further improving the system's reliability and safety.

[0082] STEP04-STEP08: Isolation of the original operating equipment. After receiving manual confirmation, the system automatically closes the relevant valves of the #1 hydrolyzer in sequence: first, it closes the steam inlet and urea solution feed to stop ammonia production, and then it closes the hydrolyzer outlet valve to achieve physical isolation. This step achieves automatic and safe shutdown of the original operating equipment, preparing it for subsequent maintenance or restart.

[0083] 3. Status Monitoring and Process Management Module (Monitoring Layer) The system executes control functions sequentially using the MASTERSEQ algorithm. ST01-ST08 correspond to 8 steps, and the current step number is stored in the STEP output. For example... Figure 2 and Figure 8 As shown, if the READY bit of the corresponding step point is 0 or the FAILED bit is 1, the HOLD module in the algorithm will output 1, and the algorithm will remain at the current step. At this time, the FAIL condition must be cleared or the OVRD input must be set to 1 for the step to increment to the next number. If the SUCCESS bit of the corresponding step point becomes 1, the algorithm will automatically increment to the next step number.

[0084] The system provides the associated device status information to MASTERSEQ via the DEVICESEQ algorithm and controls specific devices. This algorithm configures an internal fault timer that monitors the elapsed time during device operation. When the PASS or FAIL input becomes 1, the timer stops accumulating time. When the RDY input is 1, it indicates that the device is ready for remote startup, and the value of the RDY input is then transmitted to the READY bit at the step point. When the FAIL input is 1, it indicates that the device has failed, and the value of the FAIL input is transmitted to the FAILED bit at the step point. When the PASS input is 1, it indicates that the associated device has completed the operation, and the value of the PASS input is transmitted to the SUCCESS bit at the step point.

[0085] The system combines the MASTERSEQ and DEVICESEQ algorithms to execute each step in a preset logical order and monitors the execution result of each step in real time (such as whether the valve has reached the command position). If a step times out or fails, the process is automatically paused and an alarm is issued to prompt the operator to intervene.

[0086] Based on this invention, the following alternative implementations can be considered: Fully automated no-confirmation solution: In highly reliable systems, the "manual confirmation" step in STEP03 can be eliminated. Instead, the system automatically judges a more comprehensive set of parameters (such as the ring network pressure being stable within the set range, the outlet flow rate of #2 hydrolyzer being greater than that of #1, and the pressure, temperature, and liquid level of the hydrolyzer). Once the conditions are met, the system automatically executes the subsequent steps, achieving a completely unattended switching process.

[0087] Flow balancing scheme: Instead of using the "fixed rate closing control valve", the alternative can introduce a main controller, which uses the total ammonia demand of the ring network as the set value, and simultaneously performs reverse coordinated control on the outlet control valves of hydrolyzers #1 and #2. One valve is closed proportionally and the other is opened proportionally to maintain a constant total flow rate, which further ensures a smooth and uninterrupted switching of the ammonia supply source.

[0088] Example 3 To achieve the above embodiments, such as Figure 11 As shown, this embodiment also provides an automatic switching device 10 for a urea hydrolyzer system. The device 10 includes a status scanning and logic verification module 100, an automatic valve control and pressure reference setting module 200, a valve linear closing and manual adjustment module 300, and a manual confirmation and isolation process triggering module 400.

[0089] The status scanning and logic verification module 100 scans the equipment status parameters and valve position status of the parallel urea hydrolyzer in real time based on the program controller, and generates a switching permission signal through logic AND operation. The automatic control and pressure reference setting module 200 for regulating valves puts the standby hydrolyzer outlet regulating valve into automatic control mode and sets its pressure reference value according to the current ring network pressure to achieve stable injection of ammonia mixed gas. The linear closing and manual adjustment module 300 gradually closes the original operating hydrolyzer outlet regulating valve at a preset linear closing rate, while simultaneously controlling its opening change through manual mode to maintain stable ring network pressure. The manual confirmation and isolation process triggering module 400 provides a manual confirmation interface to the operators. After confirming that the ring network pressure is stable based on the DCS screen parameters, it triggers the isolation process of the original operating equipment and completes the switch.

[0090] Furthermore, the aforementioned global feature encoding module 100 is also used for: The standby hydrolyzer's ammonia injection status signal, outlet isolation valve, outlet ring network isolation valve, fully open status of the outlet valve, and fully closed status of the outlet regulating valve are verified through logical AND operations. If any verification condition is not met, the current step number is maintained through the HOLD module until all conditions are met, at which point the step number is incremented.

[0091] Furthermore, the aforementioned automatic control and pressure reference setting module 200 for regulating valves is also used for: Set the pressure setting value of the outlet regulating valve to the current ring network pressure value; The MASTERSEQ algorithm monitors the valve opening changes in real time, and triggers step increments when the valve opening reaches the preset target value.

[0092] Furthermore, the aforementioned linear closing and manual adjustment module 300 of the regulating valve is also used for: The outlet regulating valve of the original hydrolyzer is gradually closed at a preset, slow, linear rate. The actual valve opening value is collected in real time using the DEVICESEQ algorithm. When the deviation between the actual opening and the target opening exceeds 5%, a timeout alarm is triggered.

[0093] Furthermore, the aforementioned manual confirmation and isolation process triggering module 400 is also used for: The pressure fluctuation range of the ring network can be displayed in real time through the DCS screen; If the ring network pressure fluctuation does not exceed the set threshold for 30 consecutive seconds, the operator is allowed to click the manual confirmation button to trigger the subsequent isolation process. Furthermore, device 10 is also used for: The main controller simultaneously adjusts the opening of the outlet valves of hydrolyzers #1 and #2, so that valve #1 is closed proportionally while valve #2 is opened proportionally, thus maintaining a constant total ammonia flow rate in the ring network. The main controller dynamically adjusts the valve opening ratio according to the real-time ammonia demand to ensure that the total flow deviation does not exceed 10% during the switching process.

[0094] An automatic switching device for a urea hydrolyzer system according to an embodiment of the present invention can realize the full-process automatic switching of the urea hydrolyzer system, improve operational safety and reliability, shorten the switching time to within 45 seconds, and effectively control the ring network pressure fluctuation within ±0.005MPa during the switching process, ensuring the continuity and stability of ammonia supply to the denitrification system.

[0095] To implement the methods of the above embodiments, the present invention also provides a computer device, such as... Figure 12 As shown, the computer device 600 includes a memory 601 and a processor 602; wherein, the processor 602 reads executable program code stored in the memory 601 to run a program corresponding to the executable program code, so as to implement the various steps of the method described above.

[0096] To implement the above embodiments, this application also proposes a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the method described in the foregoing embodiments.

[0097] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0098] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. An automatic switching method for a urea hydrolyzer system, characterized in that, include: S1, based on the real-time scanning of the equipment status parameters and valve position status of the parallel urea hydrolyzer by the program controller, generates a switching permission signal through logical AND operation; S2, put the standby hydrolyzer outlet regulating valve into automatic control mode, and set its pressure reference value according to the current ring network pressure to achieve stable injection of ammonia gas mixture. S3 gradually closes the outlet regulating valve of the original hydrolyzer at a preset linear closing rate, while controlling its opening change in manual mode to maintain stable ring network pressure. S4 provides a manual confirmation interface to operators. After confirming that the ring network pressure is stable based on the DCS screen parameters, it triggers the isolation process of the original operating equipment and completes the switchover.

2. The method as described in claim 1, characterized in that, S1 includes: S11 verifies the standby hydrolyzer's ammonia injection status signal, outlet isolation valve, outlet ring network isolation valve, fully open status of the outlet valve, and fully closed status of the outlet regulating valve through logical AND operation. S12, when any verification condition is not met, the current step number is maintained through the HOLD module until all conditions are met, and then the step number is incremented.

3. The method as described in claim 1, characterized in that, The S2 includes: S21, set the pressure setting value of the outlet regulating valve to the current ring network pressure value; S22, the MASTERSEQ algorithm is used to monitor the change in valve opening in real time. When the valve opening reaches the preset target value, the step increment is triggered.

4. The method as described in claim 1, characterized in that, The S3 further includes: S31, gradually close the original operating hydrolyzer outlet regulating valve at a preset slow linear rate; S32 uses the DEVICESEQ algorithm to collect the actual opening value of the control valve in real time. When the deviation between the actual opening and the target opening exceeds 5%, a timeout alarm is triggered.

5. The method as described in claim 1, characterized in that, The S4 further includes: S41 displays the ring network pressure fluctuation amplitude in real time through the DCS screen; S42: When the ring network pressure fluctuation does not exceed the set threshold for 30 consecutive seconds, the operator is allowed to click the manual confirmation button to trigger the subsequent isolation process.

6. The method as described in claim 1, characterized in that, Also includes: S5, through the main controller, simultaneously adjusts the opening changes of the outlet regulating valves of #1 and #2 hydrolyzers, so that the #1 regulating valve is closed proportionally and the #2 regulating valve is opened proportionally, so as to maintain a constant total ammonia flow rate in the ring network. S6, the main controller dynamically adjusts the valve opening ratio according to the real-time ammonia demand to ensure that the total flow deviation does not exceed 10% during the switching process.

7. An automatic switching device for a urea hydrolyzer system, characterized in that, include: The status scanning and logic verification module scans the equipment status parameters and valve position status of the parallel urea hydrolyzer in real time based on the program controller, and generates a switching permission signal through logical AND operation. The automatic control and pressure reference setting module for the regulating valve puts the standby hydrolyzer outlet regulating valve into automatic control mode and sets its pressure reference value according to the current ring network pressure to achieve stable injection of ammonia gas mixture. The linear closing and manual adjustment module of the regulating valve gradually closes the original operating hydrolyzer outlet regulating valve at a preset linear closing rate, while controlling its opening change through manual mode to maintain the stability of the ring network pressure. The manual confirmation and isolation process triggering module provides operators with a manual confirmation interface. After confirming that the ring network pressure is stable based on the DCS screen parameters, it triggers the isolation process of the original operating equipment and completes the switchover.

8. The apparatus as claimed in claim 7, characterized in that, The state scanning and logic verification module is also used for: The standby hydrolyzer's ammonia injection status signal, outlet isolation valve, outlet ring network isolation valve, fully open status of the outlet valve, and fully closed status of the outlet regulating valve are verified through logical AND operations. If any verification condition is not met, the current step number is maintained through the HOLD module until all conditions are met, at which point the step number is incremented.

9. A computer device, characterized in that, Including processor and memory: The processor reads executable program code stored in the memory to run a program corresponding to the executable program code, so as to implement the video playback quality evaluation and early warning method based on the intermediate number platform as described in any one of claims 1-6.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the video playback quality evaluation and early warning method based on the intermediate number platform as described in any one of claims 1-6.

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