Method for stabilizing subcritical gas-fired boiler generator set load under blast furnace material collapse

Abstract

The invention discloses a method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse, which comprises the following steps: establishing a blast furnace material surface collapse first-level early warning model, judging by utilizing a blast furnace stock rod speed break variable and a gas utilization rate change threshold value, establishing a blast furnace material collapse caused gas flow and heat value fluctuation second-level alarm model, and judging the blast furnace material collapse caused gas flow and heat value fluctuation second-level alarm model. The TRT static blade angle, the bypass valve and the opening threshold value of the pressure reducing valve set are used for judgment, and the judgment result is transmitted to the subcritical boiler generator set; electro-hydraulic servo automatic control transformation is carried out on a diffusion tower valve of the clean gas system, and step pressure target automatic tracking is adopted; establishing a material collapse action linkage model of a middle-layer burner of the subcritical boiler, and automatically turning down a gas regulating valve during material collapse; an air and smoke system, a steam-water system and a steam turbine DEH speed regulating system of the subcritical boiler are adjusted in a linkage mode, and steam, hearth negative pressure and power generation loads are rapidly stabilized. And long-term stable power generation under the high-load working condition is achieved, and the overload power generation risk is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of abnormality treatment of subcritical gas boiler generator sets in metallurgical power plants, in particular to a method for stabilizing the load of subcritical gas boiler generator sets under blast furnace material collapse. Background Art

[0002] In the field of subcritical gas-fired boiler generator sets in self-contained power plants in the metallurgical industry, when subcritical generator sets using blast furnace gas as fuel are in operation, blast furnace collapse often causes large fluctuations in gas pressure or calorific value, causing instantaneous fluctuations in unit load up to 10MW, seriously threatening unit safety. Especially when operating at high load, large fluctuations in gas pressure or calorific value caused by blast furnace collapse can trigger a chain reaction, endangering the safety and stability of the entire production system.

[0003] In the existing technology for handling blast furnace collapse, there is a lack of effective early warning of blast furnace collapse and accurate alarm of gas fluctuations. In addition, the pressure regulation stability of the clean gas system vent tower is insufficient, and the subcritical boiler burner and related systems lack the ability to make coordinated adjustments during collapse. It is difficult to ensure the safe and stable operation of the unit under blast furnace collapse conditions. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a blast furnace collapse early warning and alarm model, which can inform the subcritical power generation workshop process of the foreseeable fluctuations in blast furnace gas pressure or calorific value after the collapse in advance so that the subcritical boiler generator set can be operated in time, providing sufficient adjustment time for the subcritical boiler generator set to ensure the safe and stable operation of the unit. A method for stabilizing the load of the subcritical gas boiler generator set under blast furnace collapse, ensuring its long-term safe and stable operation under rated high load, so as to solve the problems raised by the above-mentioned background technology.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse, comprising the following steps:

[0006] Establish a first-level early warning model for blast furnace charge surface collapse, using the blast furnace probe velocity mutation and gas utilization rate change threshold to determine the impact, and transmit the results to the subcritical boiler generator set;

[0007] Establish a two-level alarm model for gas flow and calorific value fluctuations caused by blast furnace collapse, use the TRT stator angle, bypass valve and pressure reducing valve group opening thresholds to determine, and transmit the judgment results to the subcritical boiler generator set;

[0008] The clean gas system vent tower valve was modified with electro-hydraulic servo automatic control, adopting stepped pressure target automatic tracking;

[0009] Establish a linkage model for the fuel collapse action of the middle burner of a subcritical boiler to automatically close the gas regulating valve when fuel collapse occurs;

[0010] The subcritical boiler's air and smoke system, steam-water system, and turbine DEH speed control system are adjusted in a coordinated manner to quickly stabilize steam, furnace negative pressure, and power generation load.

[0011] As a further improvement of the present invention: when the speed of the left and right probes of the blast furnace is less than -200 and the duration is greater than 5 seconds, the sound and light alarm function is triggered, and the material collapse is comprehensively judged in combination with the threshold value of the change in the blast furnace gas utilization rate, and the judgment result is transmitted from the blast furnace to the subcritical boiler generator set in the form of a signal.

[0012] As a further improvement of the present invention: in the secondary alarm model, when the stator blade angle is greater than 90, the following events are judged: the opening of bypass valve A is greater than 10%, the opening of bypass valve B is greater than 5%, the opening of pressure reducing valve group 400 is greater than 5%, and the opening of pressure reducing valve group 700 is greater than 5%. When any two of the judgment events are met, it is comprehensively judged that it is a gas fluctuation caused by blast furnace material collapse, and the comprehensive judgment result of the model is transmitted from the purification station to the subcritical boiler generator set.

[0013] As a further improvement of the present invention: during the electro-hydraulic servo automatic control transformation of the clean gas system vent tower valve, the three vent pipes adopt automatic PID tracking of stepped pressure targets to control the pressure fluctuation of the gas main within the range of ±2KPa, and regularly monitor and evaluate the pipeline pressure and adjust it for stability.

[0014] As a further improvement of the present invention: in the material collapse action linkage model, after receiving the material collapse alarm signal, the gas regulating valve is automatically closed, and the blower and induced draft fan are put into operation during normal operation to cooperate with the load adjustment operation to reduce the load.

[0015] As a further improvement of the present invention: in the material collapse linkage model, when the blast furnace material collapse warning signal comes and when the subcritical boiler load is greater than 150MW, a staged gas reduction operation is performed, with a single reduction of 40,000m3. 3 .

[0016] As a further improvement of the present invention, the first-level warning signal of blast furnace charge surface collapse and the second-level alarm signal of gas flow and calorific value fluctuation caused by blast furnace charge surface collapse are transmitted to the subcritical gas boiler generator set, which serve as feedforward signals to link the burner and target load, and automatically stabilize the load fluctuation caused by gas system fluctuation.

[0017] As a further improvement of the present invention: the gas reduction operation is performed by reducing the gas by 10,000 m in the middle layer. 3 , delay 30s, reduce 10,000m on the lower floor 3 , delay 30s, reduce 10,000m in the middle layer 3 , delay 30s, reduce 10,000m on the lower floor 3 , and the same blast furnace side signal does not repeatedly trigger the gas reduction operation within 15 minutes.

[0018] As a further improvement of the present invention: during the electro-hydraulic servo automatic control transformation of the clean gas system vent tower valve, the pressure fluctuation of the gas main is controlled within ±1KPa by optimizing the adjustment strategy and adding a buffer device.

[0019] As a further improvement of the present invention: the optimization of the adjustment strategy and the addition of a buffer device include: installing two-stage buffer devices in series on the pipe connecting the clean gas main and the discharge tower, and installing a corrugated compensator on the discharge valve inlet pipe to compensate for the pipeline vibration caused by airflow impact.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention establishes a first-level early warning model by utilizing the sudden change in blast furnace probe speed and the threshold value of gas utilization rate change, and constructs a second-level alarm model in combination with the TRT stator blade angle, bypass valve and pressure reducing valve group opening threshold to determine the blast furnace material collapse and gas flow and calorific value fluctuations, and can transmit the material collapse signal to the subcritical boiler generator set in advance, providing the boiler generator set with ample adjustment time, and performs electro-hydraulic servo automatic control transformation on the vent tower valve of the clean gas system, adopts stepped pressure target automatic tracking, optimizes the adjustment strategy and adds a buffer device, which has a good pressure stabilization effect, establishes a material collapse action linkage model for the middle burner of the subcritical boiler, and automatically closes the gas regulating valve when material collapses. At the same time, the wind and smoke system, steam-water system and turbine DEH speed control system of the subcritical boiler are adjusted in a linkage manner, which can quickly stabilize steam, furnace negative pressure and power generation load, and ensure that the unit can generate electricity stably under high-load conditions for a long time when there is sufficient gas, thereby greatly reducing the risk of overload power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0023] In order to enable a clear and complete understanding of the technical solution, the present invention is further described in conjunction with the embodiments and drawings. Obviously, the described embodiments are only some embodiments of the present invention, and all other embodiments obtained by technical personnel in the relevant field without making creative work are within the scope of protection of the present invention.

[0024] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used in the specification and appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should be further understood that the term "and / or" used in the present description and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0027] An embodiment of the present invention provides a method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse, comprising the following steps:

[0028] Establish a first-level early warning model for blast furnace charge surface collapse, using the blast furnace probe velocity mutation and gas utilization rate change threshold to determine the impact, and transmit the results to the subcritical boiler generator set;

[0029] Establish a two-level alarm model for gas flow and calorific value fluctuations caused by blast furnace collapse, use the TRT stator angle, bypass valve and pressure reducing valve group opening thresholds to determine, and transmit the judgment results to the subcritical boiler generator set;

[0030] The clean gas system vent tower valve was modified with electro-hydraulic servo automatic control, adopting stepped pressure target automatic tracking;

[0031] Establish a linkage model for the fuel collapse action of the middle burner of a subcritical boiler to automatically close the gas regulating valve when fuel collapse occurs;

[0032] The subcritical boiler's air and smoke system, steam-water system, and turbine DEH speed control system are adjusted in a coordinated manner to quickly stabilize steam, furnace negative pressure, and power generation load.

[0033] The present invention establishes a first-level early warning model by utilizing the sudden change in blast furnace probe speed and the threshold value of gas utilization rate change, and constructs a second-level alarm model in combination with the TRT stator blade angle, bypass valve and pressure reducing valve group opening threshold to determine the blast furnace material collapse and gas flow and calorific value fluctuations, and can transmit the material collapse signal to the subcritical boiler generator set in advance, providing the boiler generator set with ample adjustment time, and performs electro-hydraulic servo automatic control transformation on the vent tower valve of the clean gas system, adopts stepped pressure target automatic tracking, optimizes the adjustment strategy and adds a buffer device, which has a good pressure stabilization effect, establishes a material collapse action linkage model for the middle burner of the subcritical boiler, and automatically closes the gas regulating valve when material collapses. At the same time, the wind and smoke system, steam-water system and turbine DEH speed control system of the subcritical boiler are adjusted in a linkage manner, which can quickly stabilize steam, furnace negative pressure and power generation load, and ensure that the unit can generate electricity stably under high-load conditions for a long time when there is sufficient gas, thereby greatly reducing the risk of overload power generation.

[0034] In one embodiment of the present invention, when the speed of the left and right probes of the blast furnace is less than -200 and the duration is greater than 5 seconds, an audible and visual alarm function is triggered, and a comprehensive judgment of a material collapse is made in combination with a threshold value of a change in the blast furnace gas utilization rate, and the judgment result is transmitted from the blast furnace to the subcritical boiler generator set in the form of a signal. In an embodiment, blast furnace gas utilization rate data is collected in real time by a detection instrument in the blast furnace system, and the data is transmitted to the TRT system together with the blast furnace probe speed signal. On the other hand, multiple blast furnace gas utilization rate change thresholds can be set based on historical data and process requirements of blast furnace production. The setting of the blast furnace gas utilization rate change threshold can be based on the normal fluctuation range of gas utilization under different furnace types, furnace conditions and production conditions. When it is detected that the speed of the left and right probes of the blast furnace is less than -200 and the duration is greater than 5 seconds, an analysis of the change in blast furnace gas utilization rate is initiated. If the change in gas utilization rate reaches or exceeds the set alarm threshold, it is determined that a blast furnace material collapse has occurred.

[0035] In one embodiment of the present invention, in the secondary alarm model, when the stator blade angle is greater than 90, the following events are judged: the opening of bypass valve A is greater than 10%, the opening of bypass valve B is greater than 5%, the opening of pressure reducing valve group 400 is greater than 5%, and the opening of pressure reducing valve group 700 is greater than 5%. When any two of the judgment events are met, the comprehensive judgment is made that the gas fluctuation is caused by blast furnace material collapse, and the comprehensive judgment result of the model is transmitted from the purification station to the subcritical boiler generator set. Through the combined judgment of the stator blade angle and the opening of multiple valves, when the stator blade angle is greater than 90, and when any two of the following conditions are met, the bypass valve A opening is greater than 10%, the bypass valve B opening is greater than 5%, the pressure reducing valve group 400 opening is greater than 5%, and the pressure reducing valve group 700 opening is greater than 5%, it is possible to identify the gas flow and calorific value fluctuations caused by blast furnace material collapse. It has strong anti-interference ability. When the judgment conditions are met, it can quickly transmit an alarm signal to the subcritical boiler generator set, reserving sufficient response time for operations such as burner adjustment and load adjustment, and effectively reducing the instantaneous fluctuation amplitude of the unit load caused by gas fluctuations.

[0036] In one embodiment of the present invention, during the electro-hydraulic servo automatic control transformation of the clean gas system vent tower valve, three vent pipes adopt automatic PID tracking with a stepped pressure target to control the gas main pressure fluctuation within the range of ±2 kPa, and regularly monitor and evaluate the pipeline pressure and adjust it for stability. The vent pipe divides the gas main pressure into multiple stepped intervals through the stepped pressure target and automatic PID pressure tracking. Each interval corresponds to a different vent pipe opening priority and target pressure value. The three vent pipes are respectively equipped with independent PID controllers and pressure sensors, which are automatically optimized according to the pressure fluctuation amplitude to strictly control the gas main pressure fluctuation within the range of ±2 kPa. This can effectively avoid problems such as unstable combustion and unit load jump caused by sudden pressure changes. The regular monitoring and evaluation mechanism can promptly detect potential problems such as pipeline aging and valve wear. Through iterative parameter optimization, the system can maintain an optimal pressure-stabilized state for a long time, reducing the number of unplanned shutdowns.

[0037] In one embodiment of the present invention, in the material collapse linkage model, upon receiving a material collapse alarm signal, the gas regulating valve is automatically closed, and during normal operation, the forced draft fan and induced draft fan are activated to reduce the load in conjunction with load adjustment operations. Upon receiving the alarm signal, the gas regulating valve is automatically closed to reduce the blast furnace gas supply, preventing unstable combustion caused by a sudden increase in gas flow due to material collapse. The fluctuation amplitude of the burner inlet gas pressure is controlled, and the forced draft fan and induced draft fan are automatically activated for adjustment. By matching the air volume and gas volume in real time, negative pressure fluctuations in the furnace caused by reduced gas volume are prevented. In conjunction with load adjustment operations, the unit load reduction rate is controlled to prevent oscillation of the turbine speed control system caused by a sudden load drop.

[0038] In one embodiment of the present invention, in the material collapse linkage model, when the blast furnace material collapse warning signal comes and the subcritical boiler load is greater than 150MW, a phased gas reduction operation is performed, with a single reduction of 40,000m3. 3 Furthermore, the gas reduction operation is to reduce the gas volume by 10,000 m3 in the middle layer. 3 , delay 30s, reduce 10,000m on the lower floor 3 , delay 30s, reduce 10,000m in the middle layer 3 , delay 30s, reduce 10,000m on the lower floor 3 , and the same blast furnace-side signal will not repeatedly trigger gas reduction within 15 minutes. This phased gas reduction strategy reduces the magnitude of sudden load drops under high-load conditions (>150MW), preventing turbine speed control system oscillations caused by sudden load changes. After the program terminates, a material collapse signal from the same blast furnace within 15 minutes will no longer trigger gas reduction.

[0039] In one embodiment of the present invention, a first-level warning signal for blast furnace charge collapse and a second-level alarm signal for gas flow and calorific value fluctuations caused by blast furnace charge collapse are transmitted to a subcritical gas boiler generator set. These signals serve as feedforward signals to the burner and target load, automatically stabilizing load fluctuations caused by gas system fluctuations. This feedforward linkage between the first-level warning and second-level alarm signals transforms the hysteresis response of traditional feedback control into an early prediction, reducing the amplitude of unit load fluctuations and achieving the stability requirements of subcritical units operating at high loads. Furthermore, the feedforward signal is directly linked to the burner gas flow regulation and the turbine target load, pre-adjusting the air-to-coal ratio and steam inlet flow in advance of gas fluctuations to avoid sudden drops in combustion efficiency caused by a sudden drop in gas calorific value. Further adjustments are made using feedforward control and the unit's PID feedback control, shortening the time it takes for the system to recover stability under strong interference conditions such as blast furnace charge collapse.

[0040] In one embodiment of the present invention, during the electro-hydraulic servo automatic control transformation of the clean gas system vent tower valve, the pressure fluctuation of the gas main is controlled within ±1 KPa by optimizing the adjustment strategy and adding a buffer device.

[0041] Furthermore, the optimization of the adjustment strategy and the addition of buffer devices include: installing two-stage buffer devices in series on the pipe connecting the clean gas main and the venting tower, and installing a corrugated compensator on the inlet pipe of the venting valve to compensate for the pipeline vibration caused by the airflow impact.

[0042] Through the synergistic effect of the two-stage buffer device and the bellows compensator, the pressure fluctuation of the gas main is further compressed from ±2KPa after the traditional transformation to within ±1KPa. The two-stage buffer device can effectively absorb low-frequency pressure fluctuations and filter out high-frequency pulsations. Combined with the bellows compensator's attenuation effect on pipeline vibration, it solves the pressure oscillation of the discharge tower caused by airflow impact.

[0043] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical solutions and technical concepts of the present invention without creative mental work, and all of them fall within the scope of protection of the present invention.

Claims

1. A method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse, characterized in that: The following steps are involved: Establish a first-level early warning model for blast furnace charge surface collapse, using the blast furnace probe velocity mutation and gas utilization rate change threshold to determine the impact, and transmit the results to the subcritical boiler generator set; Establish a two-level alarm model for gas flow and calorific value fluctuations caused by blast furnace collapse, use the TRT stator angle, bypass valve and pressure reducing valve group opening thresholds to determine, and transmit the judgment results to the subcritical boiler generator set; The clean gas system vent tower valve was modified with electro-hydraulic servo automatic control, adopting stepped pressure target automatic tracking; Establish a linkage model for the fuel collapse action of the middle burner of a subcritical boiler to automatically close the gas regulating valve when fuel collapse occurs; The subcritical boiler's air and smoke system, steam-water system, and turbine DEH speed control system are adjusted in a coordinated manner to quickly stabilize steam, furnace negative pressure, and power generation load.

2. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 1, characterized in that: When the speed of the left and right probes of the blast furnace is less than -200 and the duration is greater than 5 seconds, the sound and light alarm function is triggered, and the material collapse is comprehensively judged based on the threshold of the change in the blast furnace gas utilization rate. The judgment result is transmitted from the blast furnace to the subcritical boiler generator set in the form of a signal.

3. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 2, characterized in that: In the secondary alarm model, when the stator blade angle is greater than 90, the following events are judged: bypass valve A opening > 10%, bypass valve B opening > 5%, pressure reducing valve group 400 opening > 5%, and pressure reducing valve group 700 opening > 5%. When any two of the judgment events are met, it is comprehensively judged that it is a gas fluctuation caused by blast furnace material collapse, and the comprehensive judgment result of the model is transmitted from the purification station to the subcritical boiler generator set.

4. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 3, characterized in that: During the electro-hydraulic servo automatic control transformation of the vent tower valve of the clean gas system, the three vent pipes adopted automatic PID tracking of stepped pressure targets to control the pressure fluctuation of the gas main within the range of ±2KPa, and regularly monitored and evaluated the pipeline pressure and adjusted it for stability.

5. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 4, characterized in that: In the material collapse action linkage model, upon receiving the material collapse alarm signal, the gas regulating valve is automatically closed, and the blower and induced draft fan are put into operation during normal operation to cooperate with the load adjustment operation to reduce the load.

6. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 5, characterized in that: In the material collapse linkage model, when the blast furnace material collapse warning signal comes and the subcritical boiler load is greater than 150MW, the gas reduction operation is carried out in stages, with a single reduction of 40,000m3. 3 .

7. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 5, characterized in that: The first-level warning signal of blast furnace material surface collapse and the second-level alarm signal of gas flow and calorific value fluctuation caused by blast furnace material collapse are transmitted to the subcritical gas boiler generator set. They serve as feedforward signals to link the burner and target load, automatically stabilizing the load fluctuation caused by gas system fluctuations.

8. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 6, characterized in that: The gas reduction operation is to reduce the gas by 10,000 m in the middle layer. 3 , delay 30s, reduce 10,000m on the lower floor 3 , delay 30s, reduce 10,000m in the middle layer 3 , delay 30s, reduce 10,000m on the lower floor 3 , and the same blast furnace side signal does not repeatedly trigger the gas reduction operation within 15 minutes.

9. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 5, characterized in that: During the electro-hydraulic servo automatic control transformation of the vent tower valve of the clean gas system, the pressure fluctuation of the gas main was controlled within ±1KPa by optimizing the adjustment strategy and adding a buffer device.

10. The method for stabilizing the load of a subcritical gas-fired boiler generator set under blast furnace material collapse according to claim 9, characterized in that: The optimization of the adjustment strategy and the addition of buffer devices include: installing two-stage buffer devices in series on the pipeline connecting the clean gas main and the discharge tower, and installing a corrugated compensator on the discharge valve inlet pipeline to compensate for pipeline vibration caused by airflow impact.

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