Automatic control method and system for boiler coal gas heating and soot blowing

Abstract

The application discloses a kind of boiler coal gas heating soot automatic control method and system, including real-time acquisition upstream blast furnace operating state signal and / or sent to the coal gas quality analysis signal of boiler;Based on operating state signal and / or coal gas quality analysis signal, judge whether to satisfy preset soot blowing start condition;When satisfying start condition, generate and issue soot blowing control instruction sequence, control multiple soot blower sequentially execute soot blowing operation.The present application can predictively execute preventive soot blowing cycle in advance when the blast furnace collapses or pulls wind abnormally;When coal gas dust concentration exceeds the standard, automatically increase the soot blowing duration of single soot blower;When there is ammonium bisulfate sticky ash risk, the soot blowing medium temperature of specific area soot blower is improved or pulse soot blowing mode is enabled, realize the transformation from passive periodic cleaning to active prediction and adaptive response in soot blowing operation.

Description

Technical Field

[0001] This invention relates to the field of boiler maintenance technology in thermal power plants, and in particular to an automatic control method and system for boiler gas heating and soot blowing. Background Technology

[0002] During operation, the air preheater of a boiler's gas heating system is prone to ash and slag buildup on its heating surfaces. Ash accumulation severely reduces the boiler's thermal efficiency, increases flue gas temperature, leads to higher coal consumption for power generation, and can even affect the unit's load-bearing capacity, potentially causing safety accidents in severe cases. Therefore, regularly blowing soot from the boiler's heating surfaces is a crucial step in ensuring the safe, economical, and stable operation of the boiler.

[0003] Currently, the existing boiler systems of generator sets have low levels of automation in their boiler gas heating soot blowing systems, making online remote automatic soot blowing impossible. This typically relies on operators periodically visiting the soot blower control cabinet in the gas area for manual button operation, which can last for over an hour. This process is not only physically demanding and involves high ambient temperatures, but more importantly, it exposes personnel to the gas equipment area for extended periods, posing significant safety risks. Manual operation makes it difficult to ensure the precise timing, duration, and frequency of soot blowing, compromising timeliness and consistency. Insufficient soot blowing can lead to decreased efficiency, while excessive soot blowing can wear down the pipe walls, hindering the stable and efficient operation of the unit. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of this invention is to provide an automatic control method and system for boiler gas heating and soot blowing.

[0005] The technical solution adopted by this invention to solve its technical problem is: an automatic control method for boiler gas heating and soot blowing, comprising the following steps: Real-time acquisition of operating status signals from upstream blast furnaces and / or gas quality analysis signals sent to boilers; Based on the operating status signal and / or gas quality analysis signal, determine whether the preset soot blowing start conditions are met. When the start-up conditions are met, a sequence of soot blowing control commands is generated and issued to control multiple soot blowers to perform soot blowing operations in sequence. In the step of generating the soot blowing control command sequence, at least one of the following adjustments is performed: a) Based on the prediction that the dust content of the coal gas will increase, the start time of the next planned soot blowing cycle will be brought forward to before the predicted time of coal gas deterioration. b) Based on the current or predicted dust concentration level of the gas, increase the soot blowing time setting value of a single soot blower in the instruction sequence accordingly; c) Based on the concentration of nitrogen oxides in the gas and the associated risk of ammonia escape, add control parameters for increasing the temperature of the blowing medium or pulse blowing mode to the soot blowers in the corresponding flue area.

[0006] As a further improvement of the present invention: the real-time acquisition of the operating status signal of the upstream blast furnace includes monitoring the blast furnace blast pressure change rate and / or the material line descent rate; Determine whether the soot blowing start conditions are met, including: When the blast pressure mutation rate exceeds the first threshold and / or the material drop rate exceeds the second threshold, it is determined that the blast furnace has collapsed or experienced abnormal blasting, thus meeting the start-up conditions. At this time, the generated soot blowing control command sequence is a preventive soot blowing cycle covering all soot blowers, and the soot blowing time setting value of each soot blower in the cycle is increased by a first proportion compared with its normal setting value, and the start interval between two adjacent soot blowers is shortened by a second proportion compared with its normal interval.

[0007] As a further improvement of the present invention: the step of increasing the soot blowing time setting value according to the current or predicted dust concentration level of the gas is specifically as follows: A mapping table between preset dust concentration ranges and duration correction coefficients; The range and corresponding correction factor are determined based on the real-time acquired or predicted dust concentration values. Multiply the basic soot blowing time setting of the soot blower by the correction coefficient to obtain the actual soot blowing time setting.

[0008] As a further improvement of the present invention: the adjustment based on the concentration of nitrogen oxides in the coal gas and the associated ammonia escape risk includes: Real-time acquisition of ammonia slip rate signal from boiler denitrification system; When the ammonia escape rate exceeds the set threshold and continues for a first time period, it is determined that there is a risk of ammonium bisulfate sticky ash accumulation in the corresponding flue area. For the soot blower corresponding to the flue area, the generated soot blowing control command includes an instruction to raise the temperature of the soot blowing medium to a first set temperature value, and / or an instruction to operate the soot blower in a first high-frequency pulse mode.

[0009] As a further improvement of the present invention: the control parameters of the pulse soot blowing mode are specifically to control the soot blower to start and stop intermittently at a fixed frequency or a variable frequency, wherein the duration of a single "start-stop" cycle is less than the set value of the duration of the soot blower's normal continuous operation.

[0010] As a further improvement of the present invention, it also includes a flue resistance equalization control step: Real-time acquisition of differential pressure signals from multiple parallel zones in the boiler tail flue; Calculate the variance or range of differential pressure in each zone; When the variance or range exceeds the set range, for the partition with the highest differential pressure value, an enhanced soot blowing instruction is generated and executed first for the soot blower corresponding to that partition. The enhanced soot blowing instruction includes at least increasing its soot blowing time or inserting an extra round of soot blowing in that partition.

[0011] As a further improvement of the present invention, it also includes a closed-loop evaluation of the soot blowing effect and a parameter self-optimization step: After each soot blowing cycle, the change values ​​of energy efficiency characterization parameters are collected and calculated. The energy efficiency characterization parameters include the decrease in flue gas temperature, the decrease in induced draft fan current, or a weighted combination of the two. The changed value is compared with the historical benchmark value or the model prediction value; If the change value is lower than the expected range for M consecutive times, the parameter optimization process is automatically triggered: within the preset adjustment range, the blowing time, interval or sequence parameters are iteratively modified, and the energy efficiency change after modification is evaluated until a set of optimized parameters that makes the change value of the energy efficiency characterization parameter return to the expected range is found and applied.

[0012] As a further improvement of the present invention: the step of generating the soot blowing control command sequence further includes dynamically planning the soot blowing path based on infrared temperature measurement data of the boiler heating surface. Obtain pipe wall temperature distribution data reflecting the cleanliness of each heated surface; Identify low-temperature areas where the temperature is below the preset average temperature value; The execution order of soot blowers in the instruction sequence is adjusted so that soot blowers serving the low-temperature region receive higher execution priority.

[0013] The present invention also provides an automatic control system for boiler gas heating and soot blowing, comprising: The signal acquisition and fusion unit is used to acquire in real time the blast pressure signal and material line signal of the upstream blast furnace, the dust and nitrogen oxide concentration signal in the gas sent to the boiler, the ammonia escape rate signal of the boiler denitrification system, and the zone differential pressure signal of the boiler tail flue. The analysis and decision-making unit is used to perform the following operations: Based on the blast pressure signal and the material line signal, determine whether the blast furnace has experienced material collapse or abnormal blasting. Assess the ash accumulation risk level based on the dust concentration signal in the gas. The risk of sticky ash accumulation in ammonium bisulfate is assessed based on the nitrogen oxide concentration signal and the ammonia escape rate signal. Based on the partition differential pressure signal, analyze the flue resistance balance state; Based on one or more of the above analysis results, generate a soot blowing control command sequence that includes at least one of the following parameters: soot blowing sequence, soot blowing duration, soot blowing mode, and soot blowing medium temperature. The control command execution unit is used to convert the received soot blowing control command sequence into control signals that can drive the start and stop of the soot blower motor and adjust the valves of the soot blowing medium pipeline.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention intelligently determines soot blowing start conditions by acquiring real-time operating status signals and / or gas quality analysis signals from the upstream blast furnace, and performs specific adjustments when generating a soot blowing control command sequence. The entire control process is based on automatic signal analysis and decision-making and remote command execution, avoiding manual operation by personnel entering the hazardous gas area. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the process of the present invention.

[0016] Figure 2 This is a flowchart illustrating an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0018] In order to solve the technical problems in the prior art, the present invention will now be further described in conjunction with the accompanying drawings and embodiments: like Figure 1 As shown, this invention discloses an automatic control method for boiler gas heating and soot blowing, comprising the following steps: S1: Real-time acquisition of operating status signals from upstream blast furnaces and / or gas quality analysis signals sent to boilers; S2: Based on the operating status signal and / or gas quality analysis signal, determine whether the preset soot blowing start conditions are met; S3: When the start-up conditions are met, generate and issue a sequence of soot blowing control instructions to control multiple soot blowers to perform soot blowing operations in sequence.

[0019] In the step of generating the soot blowing control command sequence, at least one of the following adjustments is performed: a) Based on the prediction that the dust content of the coal gas will increase, the start time of the next planned soot blowing cycle will be brought forward to before the predicted time of coal gas deterioration. b) Based on the current or predicted dust concentration level of the gas, increase the soot blowing time setting value of a single soot blower in the instruction sequence accordingly; c) Based on the concentration of nitrogen oxides in the gas and the associated risk of ammonia escape, add control parameters for increasing the temperature of the blowing medium or pulse blowing mode to the soot blowers in the corresponding flue area.

[0020] Specifically, based on the operational status signals indicating that the blast furnace is experiencing material collapse or abnormal airflow, the dust content in the gas is predicted to increase, and a preventative soot blowing cycle is generated and executed in advance. The gas quality analysis signals indicate whether the dust concentration in the gas exceeds a preset level, and the signals can also be combined with those from the boiler denitrification system to indicate the risk of ammonium bisulfate sticky ash accumulation.

[0021] In some implementations, the control parameters for the pulse soot blowing mode are specifically designed to control the soot blower to start and stop intermittently at a fixed or variable frequency, wherein the duration of a single "start-stop" cycle is less than the set value for the duration of the soot blower's normal continuous operation.

[0022] In some implementations, the step of generating the soot blowing control command sequence further includes dynamically planning the soot blowing path based on infrared temperature measurement data of the boiler heating surface: Obtain pipe wall temperature distribution data reflecting the cleanliness of each heated surface; Identify low-temperature areas where the temperature is below the preset average temperature value; Adjust the execution order of sootblowers in the instruction sequence to give higher execution priority to sootblowers serving low-temperature areas.

[0023] This invention enhances the precise positioning and soot blowing capability based on temperature field analysis. Utilizing pipe wall temperature distribution as a direct and intuitive representation of the degree of soot accumulation, it can accurately identify the "low-temperature hotspots" with the most severe soot buildup. By dynamically adjusting the soot blowing path to prioritize these areas, the soot blowing resources are targeted, significantly improving the effectiveness of soot blowing operations.

[0024] It's important to understand that when a blast furnace experiences abnormalities such as material collapse, draft problems, or leaks in the pressure-equalizing gas filter bags, the dust content in the gas increases significantly. When the blast furnace performs a draft operation, it drastically changes the blast intensity, causing a sudden change in the gas flow rate within the furnace. When the blast pressure drops sharply, the fine particles of raw material (such as coke powder and mineral powder) that were previously supported by the airflow sink due to weakened support. Simultaneously, when the high-speed airflow reforms, it carries the falling dust upwards, causing a sharp increase in the dust content of the gas. If the draft operation is too rapid, it can also cause uneven distribution of the gas flow within the furnace, forming "pipelines" (concentrated airflow channels) in some areas. The high-speed airflow directly washes over the raw material, exacerbating the introduction of powdery materials into the gas system.

[0025] Furthermore, abnormal conditions in the blast furnace can lead to a large amount of dust in the flue gas after the subcritical boiler burns coal gas. This dust will adhere to the surface of the tube bundles of the air preheater and gas heater in the tail flue of the boiler, seriously affecting the heat exchanger's heat exchange efficiency, causing the flue gas temperature to rise and the boiler's flue gas losses to increase.

[0026] Meanwhile, when the blast furnace collapses, the combustion temperature at the center of the blast furnace rises suddenly, generating a large amount of NOx that is carried into the gas. The NOx emissions from the subcritical boiler combustion also rise abnormally. The staff needs to increase the ammonia injection to reduce the NOx emissions at the tail end. This causes some ammonia to escape and react with sulfides in the flue gas to form ammonium bisulfate. Ammonium bisulfate easily mixes with dust in the flue gas to form mud, which adheres to the air preheater pipes and gas heater pipes, causing blockage of the heat exchanger pipes, further increasing the pressure loss in the flue, and increasing the output of the blower.

[0027] In some implementations, real-time acquisition of the operating status signals of the upstream blast furnace includes monitoring the blast furnace blast pressure abrupt change rate and / or the material line descent rate; Determine whether the soot blowing start conditions are met, including: When the blast pressure mutation rate exceeds the first threshold and / or the material descent rate exceeds the second threshold, it is determined that the blast furnace has collapsed or experienced abnormal blasting, thus meeting the start-up conditions. The generated soot blowing control command sequence is a preventive soot blowing cycle covering all soot blowers. In this cycle, the soot blowing time setting value of each soot blower is increased by a first proportion compared with its normal setting value, and the start interval between two adjacent soot blowers is shortened by a second proportion compared with its normal interval.

[0028] This invention, by real-time monitoring of the blast furnace's operating status (such as material collapse and draft), can intelligently trigger and execute an enhanced preventative soot blowing cycle before the dust content in the blast furnace actually impacts the boiler system. This effectively solves the problem of rapid dust adhesion to heating surfaces due to sudden blast furnace anomalies, which prevents conventional soot blowing plans from responding in a timely manner. It transforms reactive post-event cleaning into proactive pre-event defense, significantly reducing the risk of a sudden drop in thermal efficiency or safety accidents caused by excessively rapid ash accumulation.

[0029] In some implementation methods, the soot blowing time setting is increased according to the current or predicted dust concentration level of the gas, specifically as follows: A mapping table between preset dust concentration ranges and duration correction coefficients; The range and corresponding correction factor are determined based on the real-time acquired or predicted dust concentration values. Multiply the basic soot blowing time setting of the soot blower by the correction factor to obtain the actual soot blowing time setting.

[0030] Furthermore, this invention dynamically adjusts the core parameters of the soot blowing command (such as soot blowing duration) based on real-time gas quality (such as dust concentration and nitrogen oxide concentration). When the dust concentration is high, the soot blowing intensity is automatically increased to ensure that the soot blowing force matches the actual pollution load. This overcomes the defects of "insufficient cleaning" or "excessive wear" that may exist in soot blowing with fixed parameters, and directly addresses the problem of unstable effect of the original soot blowing mode caused by large changes in gas dust content, thus achieving more refined process control.

[0031] In some implementations, adjustments are made based on the concentration of nitrogen oxides in the gas and the associated risk of ammonia escape, including: Real-time acquisition of ammonia slip rate signal from boiler denitrification system; When the ammonia escape rate exceeds the set threshold and continues for the first time period, it is determined that there is a risk of ammonium bisulfate sticky ash accumulation in the corresponding flue area. For the sootblower corresponding to the flue area, the generated sootblowing control command includes an instruction to raise the temperature of the sootblowing medium to a first set temperature value, and / or an instruction to operate the sootblower in a first high-frequency pulse mode.

[0032] Furthermore, this invention intelligently identifies the risk of ammonium bisulfate formation and adhesion by correlating the concentration of nitrogen oxides in coal gas with ammonia escape signals from the denitrification system. It then employs specific strategies, such as increasing the medium temperature or activating a pulse mode, for soot blowers in high-risk areas. Increasing the temperature helps reduce the viscosity of ammonium bisulfate, while the impact force generated by the pulse mode is more effective at removing sticky ash deposits. This effectively removes the sticky, sludge-like blockages formed by the mixture of ammonium bisulfate and dust generated by ammonia escape, improving the long-term availability and cleaning efficiency of the heat exchanger.

[0033] Some implementations also include a flue resistance equalization control step: Real-time acquisition of differential pressure signals from multiple parallel zones in the boiler tail flue; Calculate the variance or range of differential pressure in each zone; When the variance or range exceeds the set range, for the partition with the highest differential pressure value, an enhanced soot blowing instruction is generated and executed first for the soot blower corresponding to that partition. The enhanced soot blowing instruction includes at least increasing its soot blowing duration or inserting an extra round of soot blowing in that partition.

[0034] This invention can also proactively identify and correct the "pipeline effect" caused by uneven ash accumulation within the flue. By monitoring the differential pressure of each zone and calculating its dispersion, the uniformity of the flow field can be quantitatively assessed. Prioritized and intensified soot blowing is performed on the zone with the highest resistance, actively balancing the flow capacity of each channel, thereby optimizing the overall flue gas flow field and reducing the overall system pressure loss and fan energy consumption caused by local blockages.

[0035] Some implementations also include closed-loop evaluation of soot blowing effect and parameter self-optimization steps: After each soot blowing cycle, the changes in energy efficiency characterization parameters are collected and calculated. These parameters include the decrease in flue gas temperature, the decrease in induced draft fan current, or a weighted combination of the two. Compare the changes with historical benchmark values ​​or model predictions; If the change value is lower than the expected range for M consecutive times, the parameter optimization process will be automatically triggered: within the preset adjustment range, the blowing time, interval or sequence parameters will be iteratively modified, and the energy efficiency change after modification will be evaluated until a set of optimized parameters that makes the change value of the energy efficiency characterization parameter return to the expected range is found and applied.

[0036] The present invention also provides an automatic control system for boiler gas heating and soot blowing, comprising: The signal acquisition and fusion unit is used to acquire in real time the blast pressure signal and material line signal of the upstream blast furnace, the dust and nitrogen oxide concentration signal in the gas sent to the boiler, the ammonia escape rate signal of the boiler denitrification system, and the zone differential pressure signal of the boiler tail flue. The analysis and decision-making unit is used to perform the following operations: Based on the blast pressure signal and the material line signal, determine whether the blast furnace has experienced material collapse or abnormal blasting. Assess the ash accumulation risk level based on dust concentration signals in coal gas; Assess the risk of sticky ash buildup in ammonium bisulfate based on nitrogen oxide concentration signals and ammonia escape rate signals; Analyze the flue resistance balance state based on the zone differential pressure signal; Based on one or more of the above analysis results, generate a soot blowing control command sequence that includes at least one of the following parameters: soot blowing sequence, soot blowing duration, soot blowing mode, and soot blowing medium temperature. The control command execution unit is used to convert the received soot blowing control command sequence into control signals that can drive the start and stop of the soot blower motor and adjust the valves of the soot blowing medium pipeline.

[0037] The control method and system of the present invention can realize remote automated control of the entire process of boiler gas heating and soot blowing, completely eliminate personnel from entering dangerous areas, optimize the soot blowing process, and improve boiler operating efficiency.

[0038] Implementation Case 1: like Figure 2 As shown in the figure, this invention discloses an automatic control method for boiler gas heating soot blowing, which can automatically, timed and remotely start the soot blowing process according to the preset program and boiler operating parameters, accurately control the duration and cycle of soot blowing, completely avoid human intervention and realize "one-click" operation.

[0039] Among the features, an automatic circulating soot blowing program was developed, allowing for the setting of different soot blowing frequencies and time cycles. The program also includes real-time display of the gas soot blower's location and fault alarms, one-button start / stop, cycle setting (adjustable from 1 to 24 hours), and historical curve query functions. The DCS historical station records the number of soot blowing operations, facilitating process analysis, judgment, and predictive maintenance.

[0040] The soot blowing start-up response time was also set: from 1 hour for manual operation to 5 hours for automated control. Fault diagnosis accuracy is >95%. Soot blowing data is integrated into the company's SCADA system, providing data support for intelligent combustion optimization of subcritical boilers. The gas-heated soot blowing system is integrated into the subcritical generator set control system, achieving safe, efficient, and fully automated boiler soot cleaning operations. The system's effects were immediate after commissioning. Soot blowing operations became efficient, precise, and convenient, greatly reducing the workload and safety risks for operators, ensuring the cleanliness of the boiler's heating surfaces, and thus effectively improving the boiler's thermal efficiency and the unit's operational stability.

[0041] This involves identifying and acquiring I / O signals, achieving cross-system signal transmission, designing a remote slave PLC control unit, designing an intelligent data curve generation unit, designing the underlying logic and signal transmission between the PLC control unit and the DCS controller, designing a threshold-based alarm control system, designing the electrical control circuit of the soot blowing control system, designing audible and visual alarm and real-time voice alarm control components, and designing the one-button start / stop automatic cyclic soot blowing control logic code and screen function configuration. Ultimately, this achieves optimized remote control of the automatic cyclic method.

[0042] The following steps are required to implement the automatic cyclic remote control method: Step 1: Identify and acquire I / O signals First, an S7-200 PLC controller was added to the subcritical boiler sootblowing system. The PLC controller's low-level logic was written, I / O channels were configured, and intermediate relays were added to connect the field sootblower signals to the main controller DCS system, enabling cross-system signal transmission. The signals used to detect the field sootblower status are transmitted across regions from the S7-200 PLC controller signal added to the field operation box to the DCS central control unit in the electronic equipment room via signal cables. The signal cable refers to the cable used to transmit signals from the field equipment and the S7-200 controller's logic judgment program, passing through a shielded layer. Cross-regional transmission refers to the transmission from the boiler coal feeding platform area to the DCS central control unit in the subcritical power generation electronic equipment room, which refers to the control components capable of integrated control of the entire boiler power generation equipment.

[0043] Step 2: Design an intelligent generation unit for uninterrupted redundant data curves. First, all I / O signals of the coal processing system are organized based on address planning. Then, the number of equipment start-ups and shutdowns, the number of cycle actions, the duration of soot blowing, and the frequency of job operations are added to the redundant historical station for signal writing, curve marking, variable conversion, drive connection, signal saving and initialization, thereby completing the design of the intelligent generation unit for uninterrupted data curves.

[0044] A redundant historical data station system refers to a control system capable of real-time data acquisition and intelligent generation of data trends and storage files. It provides redundant data storage, with a historical data acquisition cycle of less than 500 milliseconds and historical data retention for more than two years. Signal writing, curve marking, variable conversion, driver connection, signal storage, and initialization refer to the associated process of converting data signals with unique addresses into large-scale data trend curves.

[0045] Step 3: Design an alarm control system The dynamically adjustable alarm threshold of the subcritical coal feeding system is monitored in real time. Then, the preset output signal and time-condition control logic are programmed to achieve intelligent and visual output of abnormal action alarms through the execution of the logic program. Real-time alarm pushes are then sent through the company's intelligent energy management platform. The system allows for remote monitoring of boiler soot blowing and power generation workshop operations.

[0046] In this embodiment, the thermal control engineer sets the control parameters of the soot blowing system in the control system logic according to the process operation instructions. The parameters include the start conditions of the soot blowing cycle, the total soot blowing time, the running time of a single soot blower, the soot blowing interval, and the soot blowing sequence. After the settings are completed, the operator issues a remote start command from the DCS interface in the central control room.

[0047] The remote start command is transmitted via the control network to the DPU controller located in the electronic equipment room. Upon receiving the command, the DPU first performs a safety interlock verification of the boiler's current operating status signal. If all safety conditions are met, the next step is executed; if any condition is not met, the process is interrupted and an alarm signal is issued. When the cyclic control is interrupted, or an action times out, the system's indicator panel automatically displays a voice and text alarm function.

[0048] To achieve automatic sequential start-stop control, the DCS sends a start signal to the power control circuit of the first sootblower according to the preset sootblowing sequence. This signal is then transmitted across systems to the field drive equipment, which performs the logic actions as set. This signal activates an intermediate relay, replacing the original manual button operation and connecting the sootblower motor power.

[0049] When a single sootblower is running on a timer, the DCS's built-in timer starts counting. After the preset running time for a single sootblower is reached, the DCS automatically sends a stop signal, cutting off the sootblower's motor. Then, after a preset sootblowing interval delay, the next sootblower is started.

[0050] After the cycle is completed, repeat steps 3 and 4 until all soot blowers have completed one soot blowing operation, or the preset total soot blowing time has been reached.

[0051] Throughout the soot blowing process, the DCS collects the operating status and fault signals of each sootblower in real time and uploads them to the remote operator station for graphical display. After the entire cycle is completed, the system automatically resets and prepares to execute the next cycle command.

[0052] In summary, after reading this invention document, those skilled in the art can make various other corresponding modifications to the technical solutions and concepts based on this invention without creative mental effort, and all of these modifications fall within the scope of protection of this invention.

Claims

1. An automatic control method for boiler gas heating and soot blowing, characterized in that, Includes the following steps: Real-time acquisition of operating status signals from upstream blast furnaces and / or gas quality analysis signals sent to boilers; Based on the operating status signal and / or gas quality analysis signal, determine whether the preset soot blowing start conditions are met. When the start-up conditions are met, a sequence of soot blowing control commands is generated and issued to control multiple soot blowers to perform soot blowing operations in sequence. In the step of generating the soot blowing control command sequence, at least one of the following adjustments is performed: a) Based on the prediction that the dust content of the coal gas will increase, the start time of the next planned soot blowing cycle will be brought forward to before the predicted time of coal gas deterioration. b) Based on the current or predicted dust concentration level of the gas, increase the soot blowing time setting value of a single soot blower in the instruction sequence accordingly; c) Based on the concentration of nitrogen oxides in the gas and the associated risk of ammonia escape, add control parameters for increasing the temperature of the blowing medium or pulse blowing mode to the soot blowers in the corresponding flue area.

2. The automatic control method for boiler gas heating and soot blowing according to claim 1, characterized in that, The operating status signals include monitoring the blast furnace blast pressure change rate and / or the material drop rate; Determine whether the soot blowing start conditions are met, including: When the blast pressure mutation rate exceeds the first threshold and / or the material drop rate exceeds the second threshold, it is determined that the blast furnace has collapsed or experienced abnormal blasting, thus meeting the start-up conditions. At this time, the generated soot blowing control command sequence is a preventive soot blowing cycle covering all soot blowers, and the soot blowing time setting value of each soot blower in the cycle is increased by a first proportion compared with its normal setting value, and the start interval between two adjacent soot blowers is shortened by a second proportion compared with its normal interval.

3. The automatic control method for boiler gas heating and soot blowing according to claim 1, characterized in that, The setting for increasing the soot blowing time based on the current or predicted dust concentration level of the coal gas is as follows: A mapping table between preset dust concentration ranges and duration correction coefficients; The range and corresponding correction factor are determined based on the real-time acquired or predicted dust concentration values. Multiply the basic soot blowing time setting of the soot blower by the correction coefficient to obtain the actual soot blowing time setting.

4. The automatic control method for boiler gas heating and soot blowing according to claim 1, characterized in that, The adjustment based on the concentration of nitrogen oxides in the coal gas and the associated ammonia escape risk includes: Real-time acquisition of ammonia slip rate signal from boiler denitrification system; When the ammonia escape rate exceeds the set threshold and continues for a first time period, it is determined that there is a risk of ammonium bisulfate sticky ash accumulation in the corresponding flue area. For the soot blower corresponding to the flue area, the generated soot blowing control command includes an instruction to raise the temperature of the soot blowing medium to a first set temperature value, and / or an instruction to operate the soot blower in a first high-frequency pulse mode.

5. The automatic control method for boiler gas heating and soot blowing according to claim 4, characterized in that, The control parameters for the pulse soot blowing mode are specifically designed to control the soot blower to start and stop intermittently at a fixed or variable frequency, wherein the duration of a single "start-stop" cycle is less than the set value for the duration of the soot blower's normal continuous operation.

6. The automatic control method for boiler gas heating and soot blowing according to claim 1, characterized in that, It also includes the flue resistance equalization control step: Real-time acquisition of differential pressure signals from multiple parallel zones in the boiler tail flue; Calculate the variance or range of differential pressure in each zone; When the variance or range exceeds the set range, for the partition with the highest differential pressure value, an enhanced soot blowing instruction is generated and executed first for the soot blower corresponding to that partition. The enhanced soot blowing instruction includes at least increasing its soot blowing time or inserting an extra round of soot blowing in that partition.

7. The automatic control method for boiler gas heating and soot blowing according to claim 1, characterized in that, It also includes closed-loop evaluation of soot blowing effect and parameter self-optimization steps: After each soot blowing cycle, the change values ​​of energy efficiency characterization parameters are collected and calculated. The energy efficiency characterization parameters include the decrease in flue gas temperature, the decrease in induced draft fan current, or a weighted combination of the two. The changed value is compared with the historical benchmark value or the model prediction value; If the change value is lower than the expected range for M consecutive times, the parameter optimization process is automatically triggered: within the preset adjustment range, the blowing time, interval or sequence parameters are iteratively modified, and the energy efficiency change after modification is evaluated until a set of optimized parameters that makes the change value of the energy efficiency characterization parameter return to the expected range is found and applied.

8. The automatic control method for boiler gas heating and soot blowing according to claim 1, characterized in that, The step of generating the soot blowing control command sequence also includes dynamically planning the soot blowing path based on the infrared temperature measurement data of the boiler heating surface: Obtain pipe wall temperature distribution data reflecting the cleanliness of each heated surface; Identify low-temperature areas where the temperature is below the preset average temperature value; The execution order of soot blowers in the instruction sequence is adjusted so that soot blowers serving the low-temperature region receive higher execution priority.

9. An automatic control system for boiler gas heating and soot blowing, characterized in that, include: The signal acquisition and fusion unit is used to acquire in real time the blast pressure signal and material line signal of the upstream blast furnace, the dust and nitrogen oxide concentration signal in the gas sent to the boiler, the ammonia escape rate signal of the boiler denitrification system, and the zone differential pressure signal of the boiler tail flue. The analysis and decision-making unit is used to perform the following operations: Based on the blast pressure signal and the material line signal, determine whether the blast furnace has experienced material collapse or abnormal blasting. Assess the ash accumulation risk level based on the dust concentration signal in the gas. The risk of sticky ash accumulation in ammonium bisulfate is assessed based on the nitrogen oxide concentration signal and the ammonia escape rate signal. Based on the partition differential pressure signal, analyze the flue resistance balance state; Based on one or more of the above analysis results, generate a soot blowing control command sequence that includes at least one of the following parameters: soot blowing sequence, soot blowing duration, soot blowing mode, and soot blowing medium temperature. The control command execution unit is used to convert the received soot blowing control command sequence into control signals that can drive the start and stop of the soot blower motor and adjust the valves of the soot blowing medium pipeline.

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