Plasma ignition device, operation method and system

Abstract

The invention discloses a plasma ignition device and an operation method and system, and belongs to the technical field of thermal power generation. The operation method comprises the steps that the DCS controller collects state information of the plasma generator, the plasma combustor, the isolation transformer, the rectifier cabinet and the cooling water system; according to the collected state information, whether the cooling water system and the rectifier cabinet operate normally or not is judged, if the judgment result is normal, analysis is conducted according to the monitoring result of the flame monitoring system, feature extraction is conducted according to the analysis result, and the state of the plasma generator is predicted according to the feature extraction result; if it is predicted that the plasma energy generator can be used, the combustion stability of the plasma combustor is judged; and according to the combustion stability of the plasma combustor, whether the plasma combustor operates or not is determined. According to the method, the operation complexity is greatly simplified, the possibility of insufficient ignition stable combustion capacity or ignition failure is reduced, and the equipment safety is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of thermal power generation technology, specifically to a plasma ignition device, operating method, and system. Background Technology

[0002] In traditional power generation, boiler ignition has long relied on fuel oil systems. While this method meets basic ignition requirements, it has numerous drawbacks. Fuel oil systems are expensive to operate; the storage and transportation of fuel oil require significant manpower, resources, and capital, and also carry safety risks. Poor management can easily lead to serious accidents such as fires and explosions. Furthermore, fuel oil combustion produces large amounts of pollutants, such as sulfur dioxide and nitrogen oxides, causing significant environmental pollution and contradicting current green development principles. To address these issues, plasma ignition technology has emerged. This technology uses high-temperature plasma generated by direct current in a specific atmosphere to directly ignite pulverized coal, successfully achieving oil-free ignition start-up and stable combustion operation of boilers. This not only significantly reduces power generation costs and fuel oil-related expenses but also effectively reduces pollutant emissions.

[0003] However, with the continuous development of the power industry, existing plasma ignition devices struggle to maintain stable combustion when the boiler is operating at low load or the coal quality is poor. Ignition failure, combustion fluctuations, and even flameout occur frequently. This not only seriously affects the normal start-up and stable operation of the boiler but may also lead to equipment damage and safety accidents.

[0004] Furthermore, existing plasma ignition devices are designed and optimized for specific coal qualities, and their ignition and combustion stability performance drops significantly when the actual coal quality changes. Coal from different regions and batches varies in key indicators such as calorific value, volatile matter, and ash content, making it difficult for existing systems to adapt to such diverse coal combustion requirements. Summary of the Invention

[0005] To address the shortcomings of existing plasma ignition devices, such as insufficient ignition and combustion stability, and susceptibility to ignition failure, combustion fluctuations, or even flameout under low load or poor coal quality, this invention provides an operating method for a plasma ignition device. A DCS controller collects status information from the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system to determine the current operational probability of the plasma burner. This significantly simplifies operation, reduces the likelihood of insufficient ignition and combustion stability or ignition failure, and ensures equipment safety.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] In a first aspect, the present invention provides a plasma ignition device, comprising: a plasma generator, a plasma burner, an isolation transformer, a rectifier cabinet, and a cooling water system; The isolation transformer converts the AC power on the busbar into DC power and sends it to the rectifier cabinet. The rectifier cabinet supplies the DC power to the plasma generator. The plasma generator ionizes the compressed air by applying a large DC current between the cathode and anode electrodes to generate an electric arc. The plasma burner amplifies the generated electric arc to ignite the pulverized coal. The plasma generator uses a single-channel carrier airflow to produce high-temperature plasma, forming an electric arc. The primary central tube and secondary combustion tube of the plasma burner are cooled by primary air; The plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system are all connected to the DCS controller; the plasma generator is also connected to the cooling water system. The plasma burner is equipped with an image flame monitoring system.

[0008] Secondly, the present invention provides a method for operating a plasma ignition device, comprising: The DCS controller collects status information from the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system. Based on the collected status information, determine whether the cooling water system and rectifier cabinet are operating normally. If the determination result is normal, analyze the monitoring results of the flame monitoring system at the same time, and generate switch signals and flame intensity analog signals after analysis. Feature extraction is performed on the generated switch signal and flame intensity analog signal. The state of the plasma generator is predicted based on the feature extraction results. If the plasma generator is predicted to be usable, the combustion stability of the plasma burner is determined. The decision to operate the plasma burner is based on its combustion stability.

[0009] As a further improvement of the present invention, the DCS controller collects status information of the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system, including: The DCS controller collects the anode and cathode status of the plasma generator; the cooling water return temperature of the cooling water system; the wall temperature and primary air velocity of the plasma burner; and the output current and voltage data of the isolation transformer and rectifier cabinet.

[0010] As a further improvement of the present invention, the step of determining whether the cooling water system and rectifier cabinet are operating normally based on the collected status information, and if the determination result is normal, then simultaneously analyzing the monitoring results of the flame monitoring system, and generating the following switch signals and flame intensity analog signals after analysis: The DCS controller analyzes the collected status information to determine whether the operating status of the cooling water system and the fault status of the rectifier cabinet meet the set requirements. The requirements are: in the cooling water system, at least one main pump is running and there is no fault alarm, and the rectifier cabinet has no fault display; If the operating status of the cooling water system and the fault status of the rectifier cabinet meet the set requirements, then the analysis is performed based on the monitoring results of the flame monitoring system, and the resulting switch signal and flame intensity analog signal are generated. If the operating status of the cooling water system or the fault status of the rectifier cabinet does not meet the set requirements, maintenance should be carried out.

[0011] As a further improvement of the present invention, the generated switch signal and flame intensity analog signal are subjected to feature extraction. Based on the feature extraction results, the state of the plasma generator is predicted. If the plasma generator is predicted to be usable, the combustion stability of the plasma burner is determined, including: The DCS controller extracts features from the generated digital signals and flame intensity analog signals to predict the remaining service life of each plasma generator. ; Based on the current projected remaining service life of the plasma generator To determine whether the current plasma generator is still usable; If the current plasma generator is sufficient for use, then determine the combustion stability of the plasma burner; If the current plasma generator is unusable, replace it.

[0012] As a further improvement of the present invention, the remaining service life of the plasma generator is... ,include:

[0013] In the formula, The current moment; 1. Predicted plasma generator failure time; a. Initial health index; b. Degradation rate; 3. Failure threshold. .

[0014] As a further improvement of the present invention, the step of determining whether the plasma burner is operating based on the combustion stability of the plasma burner includes: Based on the fused image of the flame, the wall temperature of the plasma burner, the primary air velocity, and the coal quantity, a comprehensive stability index of the plasma burner is formed; Based on the comprehensive stability index of the plasma burner, determine whether the combustion stability of the plasma burner is good, slightly fluctuating, or on the verge of extinction; When the combustion stability of the plasma burner is good or slightly fluctuating, the plasma burner operates; When the combustion stability of the plasma burner is on the verge of extinction, the plasma burner is prohibited from starting and is immediately shut down.

[0015] As a further improvement of the present invention, the determination of whether the combustion stability of the plasma burner is good, slightly fluctuating, or on the verge of extinction according to the comprehensive stability index of the plasma burner includes: Based on the shape, brightness, pulsation frequency of the fused image flame, as well as the wall temperature of the plasma burner, the primary air velocity, and the coal quantity, a comprehensive stability index CSI = of the plasma burner is formed; Set a low threshold Th_low and a high threshold Th_high, and Th_low < Th_high; When CSI ≥ Th_high, the combustion of the plasma burner is in the optimal operation range and is in a good state; When Th_low < CSI < Th_high, it is in a slightly fluctuating state; When CSI < Th_low, the combustion of the plasma burner is already in a dangerous state and is on the verge of extinction.

[0016] As a further improvement of the present invention, the operation of the plasma burner when the combustion stability of the plasma burner is good or slightly fluctuating includes: When the combustion stability of the plasma burner is good or slightly fluctuating, the operation of the plasma burner is when it starts; Then the DCS controller will call the FSSS logic to perform a safety preview of the upcoming instruction, check whether there are conflicts violating the safety regulations. If not, the plasma burner starts; When the combustion stability of the plasma burner is good or slightly fluctuating, the operation of the plasma burner is to maintain its original operating state, and the DCS controller does not adjust the current equipment.

[0017] In a third aspect, the present invention provides an operating system for a plasma ignition device, including: A status information module: used for the DCS controller to collect the status information of the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system; Analysis Result Module: Used to determine whether the cooling water system and rectifier cabinet are operating normally based on the collected status information. If the judgment result is normal, it will also analyze the monitoring results of the flame monitoring system and generate switch signals and flame intensity analog signals after analysis. Combustion stabilization module: used to extract features from the generated switch signals and flame intensity analog signals. Based on the feature extraction results, the state of the plasma generator will be predicted. If the plasma generator is predicted to be usable, the combustion stability of the plasma burner will be determined. Operation Module: Used to determine whether the plasma burner should be operated based on the combustion stability of the plasma burner.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This method comprehensively collects status information from the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system through a DCS controller, providing a solid data foundation for subsequent accurate judgment and operation, and compensating for the shortcomings of traditional methods in information acquisition. Based on the judgment that the cooling water system and rectifier cabinet are operating normally, this method further combines the monitoring results of the flame monitoring system to deeply analyze and generate switch signals and flame intensity analog signals. By extracting features from the signals, the status of the plasma generator can be accurately predicted. Based on the prediction method of multi-source information fusion and deep analysis, compared with traditional single-parameter judgment, the accuracy and reliability of prediction are improved, and potential problems can be detected in advance, avoiding ignition failure or combustion fluctuations caused by plasma generator abnormalities, thus enhancing ignition stability from the source. Secondly, this method determines whether the plasma burner is in operation based on its combustion stability; this dynamic and flexible operating strategy fully considers the actual needs of the equipment under different operating conditions. Under harsh conditions such as low load or poor coal quality, the operating status can be adjusted in real time according to the combustion stability, effectively avoiding combustion instability or even flameout caused by forced operation, significantly improving the equipment's adaptability to different coal qualities, and broadening the application range of plasma ignition devices.

[0019] Furthermore, this method utilizes a DCS controller to automatically determine the feasibility of equipment operation, greatly simplifying the operation process and reducing the technical threshold and labor intensity for operators. Operators no longer need to rely on complex subjective judgments based on experience; they only need to operate according to the clear instructions given by the system, effectively reducing operational errors caused by human factors and further reducing the possibility of insufficient ignition stability or ignition failure. Simultaneously, it ensures the safe and stable operation of the equipment, reduces the risk of equipment failure and damage, extends equipment lifespan, reduces maintenance costs, and provides a strong guarantee for the efficient and reliable operation of the plasma ignition device. Attached Figure Description

[0020] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. In the drawings: Figure 1 This is a schematic flowchart illustrating the operation method of a plasma ignition device according to the present invention. Figure 2 This is a schematic diagram of the operating system of a plasma ignition device according to the present invention. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] To address the problems of insufficient ignition and combustion stability in existing plasma ignition devices, which are prone to ignition failure, combustion fluctuations, or even flameout under low load or poor coal quality, and have poor coal quality adaptability, this invention provides a plasma ignition device, including: a plasma generator, a plasma burner, an isolation transformer, a rectifier cabinet, and a cooling water system.

[0024] The isolation transformer converts the alternating current on the busbar into direct current and sends it to the rectifier cabinet. The rectifier cabinet then supplies the direct current to the plasma generator. The plasma generator ionizes the compressed air by applying a large direct current between the cathode and anode electrodes, generating an electric arc. The plasma burner amplifies the generated electric arc to ignite the pulverized coal.

[0025] The plasma generator includes a cathode, an anode, and a cooling water chamber; the plasma generator uses a single-channel carrier airflow to generate high-temperature plasma.

[0026] The plasma generator employs a coaxial single-chamber structure, and the plasma arc generated is produced by compressed air. A stable, high-current is applied between the cathode and anode electrodes, ionizing the compressed air within the hollow electrode cylinders to form plasma with high-temperature conductivity. Compressed air entering the inlet chamber compresses the plasma and blows it out of the anode cylinder, creating a continuous and stable high-temperature plasma flow. The plasma generator uses pressurized, clean, and dry air as the carrier air; in this design, compressed air is used.

[0027] During boiler ignition and low-load stable combustion, the plasma burner is activated to ignite other pulverized coal plasma burners, achieving cold ignition and low-load stable combustion. During normal boiler operation, the plasma generator is shut down, and the plasma burner functions as the main plasma burner. The plasma burner features a staged flame expansion structure, including a primary central cylinder, a secondary combustion cylinder, and an outer wall cylinder. The centerlines of the primary central cylinder, secondary combustion cylinder, and outer wall cylinder are all on the same axis. The primary central cylinder and secondary combustion cylinder are cooled by their outer layer of cold primary air to ensure safe operation. The plasma burner is an internal combustion type, employing a staged expansion principle to ignite a large amount of pulverized coal with the limited energy of the generator. The plasma burner nozzle and outlet momentum ensure the flow field of the plasma burner, maximizing the characteristics of the aerodynamic field within the furnace.

[0028] The plasma burner is equipped with metal temperature measuring points and an image flame monitoring system. The metal temperature measuring points are used to monitor the temperature of the plasma burner. The image flame monitoring system sends video signals to a video splitter in the control room and displays them on an industrial television. When the plasma burners are in operation, operators can monitor the flame images of each plasma burner in the control room. The hot air source for the cold furnace pulverizing system can be hot air from an adjacent furnace, a cold air steam heater, or a cold air oil heater to ensure that the inlet air temperature of the coal mill meets the requirements of the coal mill's drying output when the boiler is started in a cold state.

[0029] The control system of the plasma burner is connected to the DCS controller via hardwiring. All digital and analog signals are fed into the DCS controller through hardwiring, and the DCS controller operates and displays the entire plasma ignition device.

[0030] A carrier air instrumentation assembly precedes the plasma generator. This assembly is equipped with a proportional valve, pressure gauge, and pressure switch to automatically control the carrier air pressure based on power output. After passing through the instrumentation assembly, the compressed air entering the plasma generator has a pressure of 0.2-0.5 MPa. A pressure satisfaction signal is sent to the control system. The compressed air flow rate for a single generator is 90 Nm³ / h. The total carrier air volume for a single plasma generator in layers A and B of the furnace is 90 × 8 = 720 Nm³ / h.

[0031] After the plasma generator stops working, the compressed air volume is automatically adjusted to 9 Nm3 / h via a proportional valve.

[0032] The cooling water system, designed to protect the plasma generator, requires demineralized water to cool the cathode and anode. Local pressure gauges, flow switches, and manual regulating valves are installed in the instrumentation unit before the plasma generator, ensuring sufficient flow to send signals back to the control system. Demineralized water is used for cooling; the inlet cooling water pressure of the plasma generator is ≤1.0 MPa, and the pressure difference between the inlet and outlet cooling water is ≥0.4 MPa. The cooling water flow rate for a single generator is 5 t / h. After passing through the plasma generator, the return water temperature rises by 3.5℃ compared to the inlet water. The total cooling water flow rate for a single plasma generator in layers A and B of the furnace is 5 × 8 = 40 t / h. The primary air velocity measurement system is installed at the coal mill outlet to monitor the primary air velocity online, facilitating combustion adjustments by operators.

[0033] In summary, the plasma ignition device of the present invention uses a coaxial single-chamber generator to stably produce a high-temperature plasma flow, and an internal combustion-type progressively amplified plasma burner to efficiently utilize energy to ignite pulverized coal. The two are combined with a ventilation and water system for regulation and monitoring protection to synergistically enhance the ignition and stable combustion effect under low load / poor coal quality and improve coal quality adaptability.

[0034] The second objective of this invention is to provide a method for operating a plasma ignition device, such as... Figure 1 As shown, it includes: S100: The DCS controller collects status information of the plasma generator, plasma burner, isolation transformer, rectifier cabinet and cooling water system; S200: Based on the collected status information, determine whether the cooling water system and rectifier cabinet are operating normally. If the judgment result is normal, analyze the monitoring results of the flame monitoring system at the same time, and generate switch signals and flame intensity analog signals after analysis. S300: Perform feature extraction on the generated switch signal and flame intensity analog signal, and predict the state of the plasma generator based on the feature extraction results. If the plasma generator is predicted to be usable, then determine the combustion stability of the plasma burner. S400: Determine whether the plasma burner should be operated based on the combustion stability of the plasma burner.

[0035] The following section provides a further explanation of this method in conjunction with specific details.

[0036] The DCS controller collects relevant data such as the anode cooling water return temperature of the plasma generator, the pressure of the carrier air main pipe, the metal wall temperature of the plasma burner, the primary air velocity, and the output current and voltage of the rectifier cabinet.

[0037] The DCS controller analyzes the collected data to determine the operating status of the cooling water system and the fault status of the rectifier cabinet. Specifically, in the cooling water system, at least one main pump must be running without any fault alarms, and the rectifier cabinet must display no faults. If the operating status of the cooling water system and the fault status of the rectifier cabinet meet the set requirements, the controller simultaneously analyzes the video stream output from the image flame monitoring system, generating switch signals and analog flame intensity signals. If the operating status of the cooling water system and the fault status of the rectifier cabinet do not meet the requirements, personnel must perform maintenance until these conditions are met.

[0038] Specifically, the DCS controller extracts features from the generated switching signals and flame intensity analog signals, and calculates the health index of each plasma generator. and remaining service life , Health Index:

[0039] Remaining service life:

[0040] In the formula, Features extracted; The weights are set based on the importance or reliability of the features, or they can be obtained through training with historical data. For each feature n, there is a corresponding health sub-indicator, where i = 1, 2, 3, ..., n; The current moment; t represents the predicted failure time of the plasma generator; a represents the initial health index; b represents the degradation rate; and t represents the operating time.

[0041] Then when Drop to failure threshold At that time, the corresponding time satisfy:

[0042] Solving for:

[0043] Based on the remaining service life of the currently predicted plasma generator , it is determined whether the current plasma generator can still be used. If it can still be used, it is then determined whether the plasma burner can be used. If it cannot be used, the plasma generator is replaced.

[0044] According to the monitoring results of the flame monitoring system, the shape, brightness, and pulsation frequency of the fused image flame are obtained. Based on the shape, brightness, pulsation frequency of the fused image flame, as well as the wall temperature of the plasma burner, the primary air velocity, and the coal quantity, a comprehensive stability index CSI of the plasma burner is formed, with a range of [0, 1]. The closer it is to 1, the more stable it is; Set a low threshold Th_low and a high threshold Th_high, and Th_low < Th_high; Th_high ∈ [0.70, 0.85], which is the boundary value for dividing the good state and the slightly fluctuating state; Th_low ∈ [0.35, 0.50], which is the boundary value for dividing the slightly fluctuating state and the state of approaching flameout; When CSI ≥ Th_high, the combustion of the plasma burner is in the optimal operation range, which is a good state; When Th_low < CSI < Th_high, it is a slightly fluctuating state; When CSI < Th_low, the combustion of the plasma burner is already in a dangerous state, which is the state of approaching flameout.

[0045] Comprehensively judge whether the combustion stability of a single plasma burner is good, slightly fluctuating, or approaching flameout. According to the corresponding stability, the DCS controller combines the enabling signals from the cooling water, carrier air, and electrical subsystems through logical AND operations into a global plasma system startup enabling signal.

[0046] If the combustion stability of the plasma burner is good and all the above-mentioned subsystem enabling signals are normal, it is allowed to operate; If the combustion stability of the plasma burner is slightly fluctuating and all the above-mentioned subsystem enabling signals are normal, it is allowed to operate, but an alarm is issued simultaneously; If the combustion stability of the plasma burner is approaching flameout, it is prohibited to start and the machine is immediately shut down. When the burner is in the state of approaching flameout, unburned coal powder or combustible gas may have accumulated in its combustion chamber. If starting or continuing to operate is allowed at this time, the plasma arc may instantaneously ignite the accumulated substances, triggering a furnace explosion, causing equipment damage or even personal injury. Prevent the occurrence of explosion accidents.

[0047] Judging whether there is a possibility of starting currently greatly simplifies the operation complexity.

[0048] All acquired data is stored as historical data on the DCS controller server, with a time resolution down to the second or even millisecond level. This provides valuable information for post-fault analysis and operational optimization. Trend curves allow for analysis of the dynamic response of various parameters during ignition, enabling optimization of the startup curve; they also allow for analysis of the changing plasma power required to maintain stable combustion when coal quality changes, accumulating operational experience for different coal types.

[0049] The command source for the plasma ignition device is located in the DCS controller.

[0050] When the plasma generator needs to be started, or when the automatic logic determines that the boiler load is below 30% and requires stable combustion, the DCS controller generates an instruction packet. This instruction includes a start command, target power value, ramp rate, and timeout period. Simultaneously, the DCS controller invokes the FSSS (Furnace Safety Monitoring System) logic to perform a safety rehearsal of the upcoming instruction, checking for any conflicts that violate safety procedures. Before being issued, the instruction is encapsulated with the target device address code, instruction sequence number, timestamp, and checksum to ensure the accuracy and traceability of transmission.

[0051] Commands are sent via the control network to the rectifier cabinet, isolation transformer, cooling water circulation pump, and carrier air proportional valve. The I / O module within the DCS controller control station is responsible for converting the logic commands from the network into actual 24VDC on / off signals (DO) or 4-20mA current signals (AO). The power setpoint sent to the rectifier cabinet is delivered to its controller in the form of a 4-20mA analog signal; while the emergency trip command is implemented by disconnecting a pair of independent, normally energized dry contacts, which is a fail-safe design.

[0052] The rectifier cabinet, isolation transformer, cooling water circulation pump, and carrier air proportional valve are connected to the receiving terminal and the instructions from the DCS controller are parsed. When the rectifier cabinet receives a power increase instruction, it first checks whether the local cooling water flow signal is normal. If it is abnormal, it refuses to execute the power increase command and feeds back the "locked-out" status through the uplink status stream.

[0053] After receiving the pressure setting signal, the carrier air proportional valve's built-in PID controller drives the valve core to move. Simultaneously, a local closed loop is formed through the valve position sensor, ensuring that the actual pressure quickly and accurately tracks the set value. The endpoint of the downward command flow is the equipment's drive mechanism: the thyristor's conduction angle, the proportional valve's coil, and the contactor's engagement.

[0054] The DCS controller sends a command to start the cooling water system and open the electric valves of the relevant pipelines; After confirming that the cooling water flow and pressure are sufficient, instruct the main air supply valve of the carrier to be opened and the pre-pressure to be adjusted. After confirming that the water and air conditions are normal and the air conditions are determined through the uplink status flow, the DCS controller sends a command to the rectifier cabinet to allow closing and set the power. After the electric arc is established, the DCS controller instructs the coal feeding system to add pulverized coal to the corresponding plasma burner. Each step in this sequence depends on the successful completion of the previous step; failure in any step will terminate the sequence and report an error, thus preventing misoperation. The "low flow" contact (DI signal) of the cooling water flow switch is directly connected in series in the trip circuit of the rectifier cabinet. Once the flow is low, the contact opens, the rectifier cabinet control circuit loses power, and the main circuit is immediately disconnected, with a response time of less than 100 milliseconds. This design follows the "fail-safe" principle; even if the DCS controller fails, the safety protection remains effective.

[0055] The DCS controller uses dedicated FSSS safety logic for rapid judgment, with a scan cycle of 50-100ms, and then issues a trip command through the DO channel. For example, a low carrier air pressure signal or a simultaneous shutdown signal of multiple plasma burners triggers the main fuel trip logic, causing the DCS controller to trip all coal feeders and plasma generators simultaneously.

[0056] Sequential interlocking is embedded in the DCS controller's sequential control program to ensure the rationality of the operating steps. If the cooling water is not confirmed to be normal, the carrier air pneumatic valve must not be opened.

[0057] The flow switch directly hard-interlocks the trip rectifier cabinet. The pressure signal and flow signal in the DCS controller form a composite judgment logic that triggers the system protection simultaneously or either one of them. At the same time, the operating status signal of the cooling water system serves as a necessary prerequisite for the rectifier cabinet to close, thereby ensuring that the plasma generator can obtain reliable cooling under any operating conditions and preventing equipment burn-out.

[0058] Specifically, in the first-level arbitrary trigger mode, the output contacts of the cooling water flow switch are directly connected in series in the trip circuit of the rectifier cabinet. In this case, if the flow rate is too low, the power will be cut off immediately.

[0059] The second-level simultaneous trigger mode allows for the simultaneous input of analog signals from the flow transmitter and signals from the pressure transmitter to the DCS controller. A soft trip command is only issued when the DCS controller receives both a low flow alarm and a low pressure alarm simultaneously. This prevents erroneous shutdowns caused by drift or interference from a single transmitter, improving operational stability.

[0060] Meanwhile, the DCS controller continuously performs signal quality diagnostics. If any sensor is found to be faulty, it will automatically switch the logic to either trigger or rely on another valid signal to prevent failure to operate.

[0061] In the protection logic of the cooling water system of the plasma ignition device, a two-out-of-one logic is used to ensure absolute safety during high-risk phases such as cold start-up; during stable operation, a two-out-of-two logic is switched to reduce unplanned downtime. The entire triggering logic is usually combined with auxiliary logic such as signal quality judgment and delay confirmation to further optimize the balance between sensitivity and reliability of the protection system.

[0062] The protection and regulation triggering logic of the carrier air system constructs a hierarchical, multi-threshold dynamic control system. During startup, the "normal pressure" signal from the pressure switch is a necessary condition for energizing the plasma generator. Only when this hard contact closes is the rectifier cabinet allowed to close; this is the first safety threshold. After startup, during operation, the pressure switch also monitors as a tripping condition: once the pressure is detected to be below the minimum operating threshold, its contacts open, directly or through fast safety logic triggering an emergency trip of the plasma generator to prevent arc instability or electrode burnout due to carrier air interruption. Simultaneously, the continuous analog signal provided by the pressure transmitter installed after the proportional valve enters the closed-loop regulation loop of the DCS controller: the DCS controller compares the actual pressure value with the set value and dynamically adjusts the proportional valve opening through a PID algorithm to achieve precise and stable pressure control. For the main pipe pressure upstream of the proportional valve, the system sets a higher early warning threshold: when the main pipe pressure drops to a certain set value, the DCS controller triggers a "low pressure" pre-alarm and may automatically execute a power reduction command to intervene in advance to prevent the pressure from further dropping to the trip value. This ensures the system continues to operate as continuously as possible while maintaining safety, avoiding unnecessary shutdowns. The entire logic achieves a step-by-step response from permission, continuous adjustment, early warning to tripping, balancing operational flexibility and protection reliability.

[0063] The triggering logic of the flame monitoring system and coal feeding system is the core of boiler safety protection, adhering to the fundamental principle of "coal can only be fed when there is a flame, and coal feeding must be stopped immediately when there is no flame." This logic employs a multi-factor judgment mechanism: typically, the analog signal of "flame intensity" from the image flame monitoring system is ANDed with the "flame / no flame" switch signal from the ultraviolet flame detector. Only when both simultaneously confirm the presence of a flame and maintain stability for a period of time does the DCS controller issue a "coal feeding permitted" command to the corresponding coal feeder and pulverized coal pipeline gate valve. This is the first safety barrier to prevent deflagration. During operation, the system continuously monitors the flame status at the millisecond level. Once flame loss is detected, the interlocking logic immediately activates, triggering sequential control: first, the pulverized coal supply to the plasma burner is immediately cut off, cutting off the fuel source; simultaneously, the DCS controller controls the corresponding plasma generator, reducing its power to the minimum value required to maintain the arc or switching to "purge mode," using carrier air to purge the plasma burner to remove residual combustibles and prepare for possible reignition. The entire process has extremely high priority and a fast response time, and is deeply integrated with the FSSS furnace safety monitoring system. When multiple plasma burners experience flame loss simultaneously, it may trigger a higher-level MFT main fuel trip to ensure furnace safety.

[0064] The triggering logic of the primary air system based on the metal temperature of the plasma burner constructs a hierarchical active protection system, aiming to intervene proactively through airflow regulation to avoid direct tripping. Specifically, two temperature thresholds are preset in the DCS controller. When the analog signal from the temperature measuring point continuously exceeds the first-level alarm threshold, the closed-loop regulation logic is triggered. The DCS controller treats this temperature value as a process variable, compares it with the set target value, and automatically calculates and outputs a command through a PID algorithm to increase the opening of the perimeter air or auxiliary air regulating damper corresponding to the plasma burner, thereby increasing the cooling airflow through the outer wall of the plasma burner. This is the first-level regulatory trigger, with the goal of proactively cooling and maintaining operation. If the temperature fails to be controlled for any reason and continues to rise, reaching the secondary high-level trip threshold, the protective logic is triggered. This signal is directly sent to the FSSS furnace safety monitoring system, which immediately issues a hard-wired trip command and executes sequential control: first, the pulverized coal supply to the plasma burner is cut off; then, its primary damper may be closed; and the plasma burner is marked as "fault isolated." This is the second-level protective trigger, aimed at preventing severe equipment burnout. Throughout the process, the temperature change trend, the damper's operating status, and the final trip signal are all displayed and recorded in real time on the DCS controller, forming a complete protection action chain and achieving a smooth transition from early warning regulation to emergency isolation.

[0065] For trip signals, a delayed confirmation is used to avoid momentary interference; for example, a flameout signal requires 2-3 seconds to trigger an action. For critical permissible conditions, signal self-holding or initial cycle detection logic is employed. All interlocks have clearly defined enable / disable switches and status indicators for easy commissioning and maintenance.

[0066] Thirdly, the present invention provides an operating system for a plasma ignition device, such as... Figure 2 As shown, it includes: Status information module 100: used by the DCS controller to collect status information of the plasma generator, plasma burner, isolation transformer, rectifier cabinet and cooling water system; Analysis Result Module 200: It is used to determine whether the cooling water system and rectifier cabinet are operating normally based on the collected status information. If the judgment result is normal, it will also analyze the monitoring results of the flame monitoring system and generate switch signals and flame intensity analog signals after analysis. Combustion stabilization module 300: It is used to extract features from the generated switch signals and flame intensity analog signals. Based on the feature extraction results, it will predict the state of the plasma generator. If the plasma generator is predicted to be usable, it will determine the combustion stability of the plasma burner. Whether to run module 400: Used to determine whether the plasma burner should run based on the combustion stability of the plasma burner.

[0067] Many embodiments and applications beyond the examples provided will be apparent to those skilled in the art upon reading the foregoing description. Therefore, the scope of this teaching should not be determined by reference to the foregoing description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

[0068] The above content provides a further detailed description of the present invention. It should not be construed that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the scope of protection of the present invention as defined by the submitted claims.

Claims

1. A plasma ignition device, characterized in that, include: Plasma generator, plasma burner, isolation transformer, rectifier cabinet and cooling water system; The isolation transformer converts the AC power on the busbar into DC power and sends it to the rectifier cabinet. The rectifier cabinet supplies the DC power to the plasma generator. The plasma generator ionizes the compressed air by applying a large DC current between the cathode and anode electrodes to generate an electric arc. The plasma burner amplifies the generated electric arc to ignite the pulverized coal. The plasma generator uses a single-channel carrier airflow to produce high-temperature plasma, forming an electric arc. The primary central tube and secondary combustion tube of the plasma burner are cooled by primary air; The plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system are all connected to the DCS controller; the plasma generator is also connected to the cooling water system. The plasma burner is equipped with an image flame monitoring system.

2. A method for operating a plasma ignition device, based on the plasma ignition device according to claim 1, characterized in that, include: The DCS controller collects status information from the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system. Based on the collected status information, determine whether the cooling water system and rectifier cabinet are operating normally. If the determination result is normal, analyze the monitoring results of the flame monitoring system at the same time, and generate switch signals and flame intensity analog signals after analysis. Feature extraction is performed on the generated switch signal and flame intensity analog signal. The state of the plasma generator is predicted based on the feature extraction results. If the plasma generator is predicted to be usable, the combustion stability of the plasma burner is determined. The decision to operate the plasma burner is based on its combustion stability.

3. The method for operating a plasma ignition device according to claim 2, characterized in that, The DCS controller collects status information from the plasma generator, plasma burner, isolation transformer, rectifier cabinet, and cooling water system, including: The DCS controller collects the anode and cathode status of the plasma generator; the cooling water return temperature of the cooling water system; the wall temperature and primary air velocity of the plasma burner; and the output current and voltage data of the isolation transformer and rectifier cabinet.

4. The method for operating a plasma ignition device according to claim 2, characterized in that, Based on the collected status information, it is determined whether the cooling water system and rectifier cabinet are operating normally. If the determination result is normal, the monitoring results of the flame monitoring system are analyzed simultaneously. The resulting switch signals and flame intensity analog signals include: The DCS controller analyzes the collected status information to determine whether the operating status of the cooling water system and the fault status of the rectifier cabinet meet the set requirements. The requirements are: in the cooling water system, at least one main pump is running and there is no fault alarm, and the rectifier cabinet has no fault display; If the operating status of the cooling water system and the fault status of the rectifier cabinet meet the set requirements, then the analysis is performed based on the monitoring results of the flame monitoring system, and the resulting switch signal and flame intensity analog signal are generated. If the operating status of the cooling water system or the fault status of the rectifier cabinet does not meet the set requirements, maintenance should be carried out.

5. The method for operating a plasma ignition device according to claim 2, characterized in that, The generated switch signal and flame intensity analog signal are subjected to feature extraction. Based on the feature extraction results, the state of the plasma generator is predicted. If the plasma generator is predicted to be usable, the combustion stability of the plasma burner is determined, including: The DCS controller extracts features from the generated digital signals and flame intensity analog signals to predict the remaining service life of each plasma generator. ; Based on the current projected remaining service life of the plasma generator To determine whether the current plasma generator is still usable; If the current plasma generator is sufficient for use, then determine the combustion stability of the plasma burner; If the current plasma generator is unusable, replace it.

6. The method for operating a plasma ignition device according to claim 5, characterized in that, The remaining service life of the plasma generator ,include: In the formula, The current moment; 1. Predicted plasma generator failure time; a. Initial health index; b. Degradation rate; 3. Failure threshold. .

7. The method for operating a plasma ignition device according to claim 2, characterized in that, The process of determining whether the plasma burner is in operation based on its combustion stability includes: Based on the fused image of flame, plasma burner wall temperature, primary air velocity, and coal quantity, a comprehensive stability index for the plasma burner is formed. Based on the comprehensive stability index of the plasma burner, the combustion stability of the plasma burner can be judged as good, slightly fluctuating, or on the verge of flameout. The plasma burner operates when the combustion stability of the plasma burner is good or only slightly fluctuating. When the combustion stability of the plasma burner is on the verge of flameout, the plasma burner must not be started and must be shut down immediately.

8. The method of operating a plasma ignition device according to claim 7, characterized in that, The determination of the combustion stability of the plasma burner as good, slightly fluctuating, or on the verge of flameout, based on the comprehensive stability index of the plasma burner, includes: Based on the flame morphology, brightness, and pulsation frequency of the fused image, as well as the plasma burner wall temperature, primary air velocity, and coal quantity, the comprehensive stability index (CSI) of the plasma burner is formed. Set a low threshold Th_low and a high threshold Th_high, where Th_low < Th_high; When CSI≥Th_high, the plasma burner is in the optimal operating range, which is a good state; When Th_low < CSI < Th_high, it is a state of slight fluctuation; When CSI < Th_low, the plasma burner is in a dangerous state, on the verge of being shut down.

9. The method of operating a plasma ignition device according to claim 7, characterized in that, The plasma burner operates when its combustion stability is good or only slightly fluctuates, including: When the combustion stability of the plasma burner is good or only slightly fluctuating, the plasma burner is considered to be running when the plasma burner is started. The DCS controller will then call the FSSS logic to perform a safety rehearsal of the instructions to be issued, and check for any conflicts that violate safety procedures. If no conflicts are found, the plasma burner will start. When the combustion stability of the plasma burner is good or fluctuates slightly, the plasma burner's operating behavior is to maintain its original operating state, and the DCS controller will not make any adjustments to the current equipment.

10. An operating system for a plasma ignition device, based on an operating method for a plasma ignition device according to any one of claims 2-9, characterized in that, include: Status information module: used by the DCS controller to collect status information of the plasma generator, plasma burner, isolation transformer, rectifier cabinet and cooling water system; Analysis Result Module: Used to determine whether the cooling water system and rectifier cabinet are operating normally based on the collected status information. If the judgment result is normal, it will also analyze the monitoring results of the flame monitoring system and generate switch signals and flame intensity analog signals after analysis. Combustion stabilization module: used to extract features from the generated switch signals and flame intensity analog signals. Based on the feature extraction results, the state of the plasma generator will be predicted. If the plasma generator is predicted to be usable, the combustion stability of the plasma burner will be determined. Operation Module: Used to determine whether the plasma burner should be operated based on the combustion stability of the plasma burner.

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