A control system and method for adding ammonia to condensate in a thermal power generating unit

Abstract

This disclosure provides a control system and method for ammonia addition to condensate in a thermal power generating unit. The system includes: an ammonia delivery system, a condensate monitoring terminal controlled and connected to the ammonia delivery system, an ammonia addition control terminal, and an ammonia storage terminal. The ammonia addition control terminal is signal-connected to both the condensate monitoring terminal and the ammonia storage terminal. The ammonia addition control terminal includes an ammonia pump connected to the ammonia storage terminal via a pipeline, an ammonia circulation loop assembly connected to the ammonia pump via a pipeline, a second data receiving module signal-connected to the condensate monitoring terminal, a conductivity deviation calculation module signal-connected to the second data receiving module, an ammonia addition control module signal-connected to both the ammonia circulation loop assembly and the ammonia delivery system, and a conductivity target threshold module and a conductivity deviation calculation module signal-connected to the ammonia delivery system.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of condensate ammonia addition technology, specifically relating to a condensate ammonia addition control system and method for thermal power generating units. Background Technology

[0002] Currently, the condensate ammonia addition systems in operating generator units (DC boilers) all employ variable frequency manual control. The primary function of ammonia addition is to control the conductivity of the condensate entering the boiler. Excessively high conductivity indicates excessive ammonia addition (when the condensate pH exceeds 13), leading to alkaline corrosion of the steam-water system. It also results in faster operation of the mixed-bed hydrogen-type system during purification, reduced cycle water production, and wasted ammonia. Conversely, excessively low conductivity leads to corrosion of thermal equipment and pipelines; corrosion intensity is greater at lower pH values ​​than at higher pH values. Therefore, maintaining the pH of the steam-water system within the acceptable range is crucial. Controlling ammonia addition to the feedwater effectively prevents corrosion of the steam-water system and thermal equipment.

[0003] The current manual control method for variable frequency drives (VFDs) mainly relies on visual observation. If the conductivity of the mixed bed outlet decreases, the operator adjusts the output of the VFD pump and then checks the conductivity at the mixed bed outlet again. If the conductivity at the mixed bed outlet is still not up to standard after one hour, the operator will continue to adjust the VFD output of the pump. This process is repeated, taking approximately 5-6 hours to bring the conductivity of the condensate outlet back to a acceptable range. This significantly increases the complexity of manual operation and results in poor control. Corrosion of the steam-water system and thermal system caused by manual control is quite common in domestic generator sets (DC boilers). Therefore, we provide a condensate ammonia addition control system for thermal power generator sets to solve this problem. Summary of the Invention

[0004] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a control system and method for adding ammonia to condensate in thermal power generating units.

[0005] A first aspect of the embodiments of this disclosure provides a condensate ammonia addition control system for a thermal power generating unit, comprising: an ammonia water delivery system end, a condensate monitoring end controlled and connected to the ammonia water delivery system end, an ammonia addition control end, and an ammonia water storage end, wherein the ammonia addition control end is signal connected to the condensate monitoring end and the ammonia water storage end respectively; The ammonia addition control terminal includes an ammonia addition pump connected to the ammonia storage terminal via a pipeline, an ammonia circulation loop assembly connected to the ammonia addition pump via a pipeline, a data receiving module II connected to the condensate monitoring terminal, a conductivity deviation calculation module connected to the data receiving module II, an ammonia addition control module connected to the ammonia circulation loop assembly and the ammonia delivery system terminal respectively, and a conductivity target threshold module and a conductivity deviation calculation module connected to the ammonia delivery system terminal.

[0006] Optionally, the ammonia water circulation loop assembly includes a circulation regulating valve and a regulating valve coefficient adjustment module. The circulation regulating valve is connected to the ammonia addition pump through a pipeline, the circulation regulating valve is connected to the condensate outlet pipeline through a pipeline, and the circulation regulating valve is connected to the ammonia water storage end through a pipeline. The regulating valve coefficient adjustment module is connected to the circulation regulating valve and the ammonia water addition control module respectively.

[0007] Optionally, the ammonia water addition control module includes a switching module connected to the ammonia water delivery system, and a coarse adjustment module and a fine adjustment module respectively connected to the switching module via signal. The coarse adjustment module and the fine adjustment module are both connected to the regulating valve coefficient adjustment module via data signal.

[0008] Optionally, the condensate monitoring terminal includes a condensate flow detection module, a water flow feedback logic module, an ammonia addition feedback component, a conductivity detection module, and a conductivity feedback logic module; Both the conductivity detection module and the condensate flow detection module are installed in the condensate outlet pipeline. The condensate flow detection module is signal-connected to the water flow feedback logic module, the water flow feedback logic module is signal-connected to the ammonia addition feedback component, the conductivity detection module is signal-connected to the conductivity feedback logic module, and the conductivity feedback logic module is signal-connected to the data receiving module.

[0009] Optionally, the ammonia addition feedback component includes a data receiving module 1 connected to the water flow feedback logic module, a condensate flow average calculation module connected to the data receiving module 1, and an ammonia addition calculation module connected to the condensate flow average calculation module. The ammonia addition calculation module is connected to the ammonia water delivery system.

[0010] Optionally, the ammonia storage end includes an ammonia storage tank connected to the ammonia pump and the circulation regulating valve via pipelines, an agitator installed inside the ammonia storage tank, and ammonia concentration detection modules installed on both sides of the inner cavity of the ammonia storage tank and arranged at equal intervals. The ammonia concentration detection modules are all connected to the ammonia delivery system end via data signals, and the ammonia delivery system end is connected to an ammonia concentration target value module via data signals.

[0011] Optionally, the ammonia storage end also includes a liquid level sensor one installed on the upper left side of the inner cavity of the ammonia storage tank, and a liquid level sensor two installed on the lower left side of the inner cavity of the ammonia storage tank. Both the liquid level sensor one and the liquid level sensor two are connected to the ammonia delivery system end for signal connection.

[0012] A second aspect of the embodiments of this disclosure provides a method for controlling the addition of ammonia to condensate in a thermal power generating unit. The method is implemented according to the aforementioned control system for adding ammonia to condensate in a thermal power generating unit, and includes: Connect the ammonia water delivery system, condensate monitoring system, ammonia addition control system, and ammonia water storage system to establish data and control connections; install multiple condensate flow detection modules on the condensate pipeline and a conductivity detection module at the outlet pipeline; connect the ammonia addition pump to the ammonia storage tank and connect it to the ammonia storage tank through the installation of a circulation regulating valve and an ammonia water return pipeline; Multiple condensate flow detection modules detect the flow rate at different locations in real time. The flow rate data is transmitted to the data receiving module 1 via the water flow feedback logic module. The average flow rate is then processed by the condensate flow rate average calculation module and transmitted to the ammonia addition calculation module. Finally, the ammonia addition data is sent to the ammonia water delivery system. The conductivity detection module detects the conductivity of condensate in real time. The conductivity data is sent to the data receiving module 2 via the conductivity feedback logic module. The conductivity deviation calculation module calculates the deviation by combining the target value provided by the conductivity target threshold module and sends the result to the ammonia water delivery system. When the average condensate flow rate changes by a rate of 10 t / (h·min) within 3 minutes or by a change of 50 t / h within 10 minutes, the ammonia water delivery system starts the coarse adjustment mode, controls the opening of the circulation regulating valve to increase, and the ammonia pump outputs at full capacity for 35 minutes. If the average condensate flow rate continues to change at a rate >5t / (h·min), continue coarse adjustment immediately; if the conductivity deviation is ≥0.2, continue coarse adjustment; if the deviation is >2.0, increase the circulation regulating valve coefficient; if the deviation is <0.2, switch to fine adjustment mode. In fine-tuning mode, the opening of the circulation regulating valve is finely adjusted according to the conductivity deviation value, with each adjustment being ±5%. The conductivity is monitored at 35-minute intervals, and adjustments are continued or maintained based on the deviation value.

[0013] The beneficial effects of the embodiments of this disclosure include: 1. By effectively measuring the average value of the condensate outlet pipeline and using this data to calculate the ammonia addition amount, and by measuring the conductivity, the ammonia addition amount can be easily adjusted based on the deviation of the condensate flow rate and conductivity to control the water quality in the furnace to a stable conductivity. This effectively improves the control of ammonia addition to the condensate, reduces the cumbersome manual operation, and avoids corrosion of the steam-water system and thermal system caused by manual control, thus effectively improving the performance.

[0014] 2. By installing a stirrer in the ammonia storage tank and using multiple ammonia concentration detection modules to detect the ammonia concentration in the tank, and comparing the data with the target value data of the ammonia concentration target value module, if the data detected by any ammonia concentration detection module differs from the target value data of the ammonia concentration target value module by more than a set threshold, the stirrer is activated to stir and mix the ammonia water. This prevents the ammonia water from remaining stagnant for a long time, which would cause sedimentation at the bottom and result in different ammonia contents at different heights in the ammonia water. This avoids affecting the final ammonia addition reaction effect and improves the usage effect. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a condensate ammonia addition control system for a thermal power generating unit according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the structure of a condensate monitoring terminal according to an embodiment of the present disclosure; Figure 3 This is a schematic diagram of the structure of an ammonia addition feedback component according to an embodiment of the present disclosure; Figure 4 This is a schematic diagram of the ammonia addition control terminal according to an embodiment of the present disclosure; Figure 5 This is a schematic diagram of the structure of an ammonia water circulation loop assembly according to an embodiment of the present disclosure; Figure 6 This is a schematic diagram of the structure of an ammonia water addition control module according to an embodiment of the present disclosure; Figure 7 This is a schematic diagram of the ammonia storage end of an embodiment of the present disclosure; Figure 8 This is a schematic diagram of the condensate ammonia addition pipeline of a condensate ammonia addition control system for a thermal power generating unit according to another embodiment of this disclosure.

[0016] In the diagram, 1. Condensate flow detection module; 2. Conductivity detection module; 3. Circulation regulating valve; 4. Ammonia pump; 5. Ammonia concentration detection module; 6. Level sensor one; 7. Level sensor two; 8. Ammonia storage tank; 9. Agitator. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0019] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0020] like Figure 1-8 As shown, a condensate ammonia addition control system for a thermal power generating unit includes: an ammonia water delivery system end, a condensate monitoring end controlled and connected to the ammonia water delivery system end, an ammonia addition control end, and an ammonia water storage end. The ammonia addition control end is signal-connected to the condensate monitoring end and the ammonia water storage end, respectively.

[0021] The ammonia addition control terminal includes an ammonia addition pump 4 connected to the ammonia storage terminal via a pipeline, an ammonia circulation loop assembly connected to the ammonia addition pump 4 via a pipeline, a data receiving module II connected to the condensate monitoring terminal, a conductivity deviation calculation module connected to the data receiving module II, an ammonia addition control module connected to the ammonia circulation loop assembly and the ammonia delivery system terminal respectively, and a conductivity target threshold module and a conductivity deviation calculation module connected to the ammonia delivery system terminal.

[0022] In some embodiments, the ammonia water circulation loop assembly includes a circulation regulating valve 3 and a regulating valve coefficient adjustment module. The circulation regulating valve 3 is connected to the ammonia addition pump 4 via a pipeline, the circulation regulating valve 3 is connected to the condensate outlet pipeline via a pipeline, and the circulation regulating valve 3 is connected to the ammonia water storage end via a pipeline. The regulating valve coefficient adjustment module is signal-connected to the circulation regulating valve 3 and the ammonia water addition control module, respectively.

[0023] In some embodiments, the ammonia water dosage control module includes a switching module connected to the ammonia water delivery system, and a coarse adjustment module and a fine adjustment module respectively connected to the switching module via signal. The coarse adjustment module and the fine adjustment module are both connected to the regulating valve coefficient adjustment module via data signal.

[0024] In some embodiments, the condensate monitoring terminal includes a condensate flow detection module 1, a water flow feedback logic module, an ammonia addition feedback component, a conductivity detection module 2, and a conductivity feedback logic module.

[0025] Both the conductivity detection module 2 and the condensate flow detection module 1 are installed in the condensate outlet pipeline. The condensate flow detection module 1 is signal-connected to the water flow feedback logic module, the water flow feedback logic module is signal-connected to the ammonia addition feedback component, the conductivity detection module 2 is signal-connected to the conductivity feedback logic module, and the conductivity feedback logic module is signal-connected to the data receiving module 2.

[0026] In some embodiments, the ammonia addition feedback component includes a data receiving module 1 signal-connected to the water flow feedback logic module, a condensate flow average calculation module signal-connected to the data receiving module 1, and an ammonia addition calculation module signal-connected to the condensate flow average calculation module. The ammonia addition calculation module is signal-connected to the ammonia water delivery system.

[0027] In some embodiments, the ammonia storage end includes an ammonia storage tank 8 connected to the ammonia pump 4 and the circulation regulating valve 3 via pipelines, an agitator 9 installed inside the ammonia storage tank 8, and ammonia concentration detection modules 5 installed on both sides of the inner cavity of the ammonia storage tank 8 and arranged at equal intervals. The ammonia concentration detection modules 5 are all connected to the ammonia delivery system end via data signals. The ammonia delivery system end is connected to an ammonia concentration target value module via data signals.

[0028] In some embodiments, the ammonia storage end also includes a level sensor 6 installed on the upper left side of the inner cavity of the ammonia storage tank 8, and a level sensor 7 installed on the lower left side of the inner cavity of the ammonia storage tank 8. Both the level sensor 6 and the level sensor 7 are connected to the ammonia delivery system.

[0029] A second aspect of the embodiments of this disclosure provides a method for controlling the addition of ammonia to condensate in a thermal power generating unit. The method is implemented according to the aforementioned control system for adding ammonia to condensate in a thermal power generating unit, and includes: S101. Connect the ammonia water delivery system, condensate monitoring system, ammonia addition control system, and ammonia water storage system for data and control. Install multiple condensate flow detection modules 1 on the condensate pipeline and a conductivity detection module 2 at the outlet pipeline. Connect the ammonia addition pump 4 to the ammonia storage tank 8, and connect it to the ammonia storage tank 8 via a circulation regulating valve 3 and an ammonia water return pipeline.

[0030] S102. The flow rate at different locations is detected in real time by multiple sets of condensate flow rate detection modules 1. The flow rate data is transmitted to the data receiving module 1 through the water flow rate feedback logic module, and then processed by the condensate flow rate average calculation module to obtain the average flow rate, which is then transmitted to the ammonia addition calculation module. Finally, the ammonia addition data is sent to the ammonia water delivery system.

[0031] S103, the conductivity detection module 2 detects the conductivity of condensate in real time. The conductivity data is sent to the data receiving module 2 via the conductivity feedback logic module. The conductivity deviation calculation module calculates the deviation in combination with the target value provided by the conductivity target threshold module and sends the result to the ammonia water delivery system.

[0032] S104. When the average condensate flow rate changes by a rate of 10t / (h·min) within 3 minutes or by a change of 50t / h within 10 minutes, the ammonia water delivery system starts the coarse adjustment mode, controls the opening of the circulation regulating valve 3 to increase, and the ammonia pump 4 to output at full power for 35 minutes.

[0033] S105. If the average condensate flow rate continues to change at a rate >5t / (h·min), continue coarse adjustment immediately. If the conductivity deviation is ≥0.2, continue coarse adjustment. If the deviation is >2.0, increase the coefficient of the circulation regulating valve 3. If the deviation is <0.2, switch to fine adjustment mode.

[0034] S106. In fine-tuning mode, the opening of the circulation regulating valve 3 is finely adjusted according to the conductivity deviation value, with each adjustment being ±5%. The conductivity is monitored every 35 minutes, and the adjustment or maintenance is continued based on the deviation value.

[0035] In this application, 1) by effectively measuring the average value of the condensate outlet pipeline and using this data to calculate the ammonia addition amount, and by measuring the conductivity, it is convenient to adjust the ammonia addition amount in different modes according to the condensate flow rate and conductivity deviation. By designing a coarse adjustment mode and a fine adjustment mode, the coarse adjustment mode is performed when the boiler power generation load changes, i.e., when the condensate flow rate changes significantly, to cope with sudden changes in condensate flow rate. When the conductivity deviation exceeds 0.2, or when the conductivity deviation is less than 0.2, fine adjustment is performed. The fine adjustment mode is performed when the boiler power generation load is stable, and the ammonia addition amount is increased or decreased according to the deviation data between the specific condensate conductivity and the conductivity target threshold. That is, the opening of the circulation regulating valve is increased or decreased by 5% to control the water quality in the boiler to remain stable at a certain conductivity. This effectively improves the control effect of ammonia addition to condensate, reduces the cumbersome manual operation, and avoids corrosion of the steam-water system and thermal system caused by manual control, thus effectively improving the use effect. 2. By installing a stirrer in the ammonia storage tank and using multiple ammonia concentration detection modules to detect the ammonia concentration in the tank, and comparing the data with the target value data of the ammonia concentration target value module, if the data detected by any ammonia concentration detection module differs from the target value data of the ammonia concentration target value module by more than a set threshold, the stirrer is activated to stir and mix the ammonia water. This prevents the ammonia water from remaining stagnant for a long time, which would cause sedimentation at the bottom and result in different ammonia contents at different heights in the ammonia water. This avoids affecting the final ammonia addition reaction effect and improves the usage effect.

[0036] Reference Figure 1-3 As shown, a condensate ammonia addition control system for a thermal power generating unit includes an ammonia delivery system, a condensate monitoring system, an ammonia addition control system, and an ammonia storage system. The ammonia delivery system is connected to the condensate monitoring system, the ammonia addition control system, and the ammonia storage system via data signals. The ammonia addition control system is connected to the condensate monitoring system and the ammonia storage system via data signals.

[0037] The condensate monitoring terminal includes a condensate flow detection module 1, a water flow feedback logic module, an ammonia addition feedback component, a conductivity detection module 2, and a conductivity feedback logic module. One conductivity detection module 2 and multiple condensate flow detection modules 1 are installed in the condensate outlet pipeline. The condensate flow detection module 1 is connected to the water flow feedback logic module via a data signal. The water flow feedback logic module is connected to the ammonia addition feedback component via a data signal. The conductivity detection module 2 is connected to the conductivity feedback logic module via a data signal. The conductivity feedback logic module is connected to the data receiving module 2 via a data signal.

[0038] The ammonia addition feedback component includes a data receiving module 1 that is connected to the water flow feedback logic module via a data signal. The data receiving module 1 is connected to the condensate flow average calculation module via a data signal. The condensate flow average calculation module is connected to the ammonia addition calculation module via a data signal. The ammonia addition calculation module is connected to the ammonia water delivery system via a data signal.

[0039] Multiple condensate flow detection modules 1 simultaneously detect condensate flow at different locations. The condensate flow average calculation module calculates the average of the condensate flow data from three different locations. Since the condensate pipeline has multiple main and auxiliary pipes, it is convenient to average the condensate flow in the condensate outlet pipeline, improving the accuracy of the final condensate flow. This facilitates the feedback of the flow data to the ammonia addition calculation module, which calculates the ammonia addition amount based on the average condensate flow, thus improving the accuracy of the ammonia addition. Furthermore, the conductivity detection module 2 detects the conductivity data in the water at the condensate outlet, and the conductivity deviation calculation module calculates the deviation between the target conductivity value and the actual measured conductivity data. This allows for different adjustment modes of the ammonia addition amount based on the condensate flow and conductivity deviation value, resulting in faster neutralization and adjustment of the condensate's conductivity and pH value. This avoids multiple ammonia addition adjustments, reducing workload, and also prevents corrosion of the steam-water system and thermal equipment.

[0040] Reference Figure 1 and 4 As shown in Figure -6, the ammonia addition control terminal includes an ammonia addition pump 4, an ammonia water circulation loop assembly, a conductivity target threshold module, a conductivity deviation calculation module, a data receiving module II, and an ammonia water addition control module. The ammonia addition pump 4 is connected to the ammonia water storage terminal via a pipeline. The ammonia addition pump 4 is also connected to the ammonia water circulation loop assembly via a pipeline. The data receiving module II is connected to the condensate monitoring terminal via a signal. The data receiving module II is also connected to the conductivity deviation calculation module via a data signal. The ammonia water circulation loop assembly is connected to the ammonia water addition control module via a data signal. The conductivity target threshold module, the conductivity deviation calculation module, and the ammonia water addition control module are all connected to the ammonia water delivery system terminal via data signals.

[0041] The ammonia water circulation loop assembly includes a circulation regulating valve 3 and a regulating valve coefficient adjustment module. The circulation regulating valve 3 is connected to the ammonia pump 4 via a pipeline. The circulation regulating valve 3 is also connected to the condensate outlet pipeline via a pipeline and to the ammonia water storage end via a pipeline. The regulating valve coefficient adjustment module is connected to the circulation regulating valve 3 and the ammonia water addition control module via data signals.

[0042] The ammonia water dosage control module includes a switching module connected to the ammonia water delivery system. The switching module is connected to a coarse adjustment module and a fine adjustment module via data signals. Both the coarse adjustment module and the fine adjustment module are connected to the regulating valve coefficient adjustment module via data signals.

[0043] When the boiler power generation load changes, resulting in a significant change in condensate flow, a coarse adjustment of the ammonia dosage is required. In this coarse adjustment mode, the coarse adjustment module sends a signal to the regulating valve coefficient adjustment module to increase the opening of the circulation regulating valve 3. Simultaneously, the ammonia pump 4 (i.e., the plunger pump) is opened to full output to cope with sudden changes in condensate flow. If the conductivity target threshold module is set to 9.4, and the conductivity deviation exceeds 0.2, coarse adjustment continues. If the conductivity deviation is less than 0.2, fine adjustment is performed. The fine adjustment mode involves issuing ammonia dosage control via a switching module. The instruction is sent to the switching module, which then feeds this instruction back to the fine-tuning module to enable fine-tuning of the ammonia addition. This involves increasing the opening of the circulation regulating valve 3 by 5%. If the deviation is greater than 0.1, the opening of the circulation regulating valve 3 is decreased by 5%. After waiting for 35 minutes, the real-time conductivity is observed and compared with the target value. This process is repeated, meaning that when the boiler power generation load is stable, the opening of the circulation regulating valve 3 is finely adjusted to gradually correct the ammonia addition, adapting to the condensate flow rate at a stable conductivity, and finally bringing the conductivity infinitely close to the target value, thereby improving the ammonia addition control effect of the condensate.

[0044] Reference Figure 1-3 As shown in Figure 8, the ammonia storage end includes an ammonia storage tank 8 connected to the ammonia pump 4 and the circulation regulating valve 3 via pipelines. An agitator 9 is installed in the ammonia storage tank 8. Ammonia concentration detection modules 5 are installed at equal intervals on both sides of the inner cavity of the ammonia storage tank 8. The ammonia concentration detection modules 5 are all connected to the ammonia delivery system end via data signals. The ammonia delivery system end is connected to the ammonia concentration target value module via data signals. A liquid level sensor 6 is installed on the upper left side of the inner cavity of the ammonia storage tank 8, and a liquid level sensor 7 is installed on the lower left side of the inner cavity of the ammonia storage tank 8. Both liquid level sensor 6 and liquid level sensor 7 are connected to the ammonia delivery system end via data signals.

[0045] The present invention also provides a method for adding ammonia to the condensate of a thermal power generating unit, comprising the following steps: S1. First, data control connections are made between the ammonia water delivery system, condensate monitoring system, ammonia addition control system, and ammonia water storage system that need to be connected to each other.

[0046] S2. Multiple condensate flow detection modules 1 are installed on the condensate pipeline, and a conductivity detection module 2 is installed near the condensate outlet pipeline. The ammonia pump 4 is connected to the ammonia storage tank 8 through a pipeline. In the circuit where the ammonia pump 4 is connected to the condensate outlet pipeline, a set of circulation regulating valves 3 is installed. The circulation regulating valves 3 are connected to the ammonia storage tank 8 through an ammonia water return pipeline.

[0047] S3. Then, while the condensate is being discharged, multiple condensate flow detection modules 1 simultaneously detect the condensate flow at different locations and finally feed back the detected flow data to the flow feedback logic module. The flow feedback logic module transmits the data to the data receiving module 1 via a data signal. The data receiving module 1 then feeds back the data obtained from the flow detection to the condensate flow average calculation module. The condensate flow average calculation module calculates the average of the condensate flow data from three different locations and feeds it back to the ammonia addition calculation module. The ammonia addition calculation module calculates the ammonia addition amount based on the average condensate flow and feeds back the final ammonia addition data to the ammonia water delivery system.

[0048] S4. Simultaneously, the conductivity detection module 2 detects the conductivity data in the water at the condensate outlet and feeds it back to the conductivity feedback logic module via a data signal. The conductivity feedback logic module then feeds this information back to the data receiving module 2, which in turn feeds this data back to the conductivity deviation calculation module. Meanwhile, the ammonia water delivery system feeds back the target conductivity value set by the conductivity target threshold module to the conductivity deviation calculation module. The conductivity deviation calculation module then calculates the deviation between the target conductivity value and the actual measured conductivity data and feeds back the final calculated data to the ammonia water delivery system.

[0049] S5. Specific data on condensate flow received from the ammonia water delivery system: When the boiler power generation load changes, i.e., the condensate flow rate changes significantly (i.e., when the average condensate flow rate after detection and calculation changes by more than 10t / (h*min) within 3 minutes or by more than 50t / h within 10 minutes), the ammonia water delivery system sends an ammonia addition control command to the switching module. The switching module then feeds this command back to the coarse adjustment module, thus initiating a coarse adjustment mode for the ammonia addition. In this mode, the coarse adjustment module sends a command to the regulating valve coefficient adjustment module to change the opening of the circulation regulating valve 3. At this time, the ammonia pump 4 (i.e., the plunger pump) is opened to full output to cope with sudden changes in condensate flow rate. After the coarse adjustment, the system waits 35 minutes to observe the results.

[0050] S6. If the calculated continuous average condensate flow rate continues to rise or fall by more than 5t / (h*min), then there is no need to wait 35 minutes. Continue to adjust the opening of the circulation regulating valve 3 according to the water flow rate. That is, control the opening of the circulation regulating valve 3 in full-open mode through the regulating valve coefficient adjustment module for coarse adjustment. Wait 35 minutes to observe the results. If the deviation value is less than 0.2, then fine adjustment is performed. The fine adjustment mode is to adjust the amount of ammonia added by increasing or decreasing the amount of ammonia added according to the deviation data between the specific condensate conductivity and the conductivity target threshold under the condition of stable boiler power generation load. That is, to fine adjust the opening of the circulation regulating valve 3 to control the water quality in the furnace to be stable at a certain conductivity. This cycle continues.

[0051] S7. By setting the conductivity of the conductivity target threshold module to 9.4, the conductivity deviation calculation module calculates the deviation value between the actual detected conductivity and the target conductivity, and finally feeds it back to the ammonia water delivery system. When the deviation value exceeds 0.2, coarse adjustment continues. If the deviation value is greater than 2.0, the coarse adjustment module feeds it back to the regulating valve coefficient adjustment module. The regulating valve coefficient adjustment module increases the coefficient k of the circulating regulating valve 3 from 1 / 24 to 1 / 18. If the deviation value is less than 0.2, fine adjustment is performed.

[0052] S8. When the conductivity deviation is less than 0.2, fine adjustment is performed. Specifically, the switching module issues an ammonia addition control command, and the switching module feeds this command back to the fine adjustment module, thereby entering the ammonia addition fine adjustment mode. Based on the conductivity deviation being less than 0.2, the opening of the circulation control valve 3 is increased by 5%, and after waiting for 35 minutes, the real-time conductivity is observed. If the deviation calculated from the deviation value is still less than 0.2, the opening of the circulation control valve 3 is increased by 5%, and after waiting for 35 minutes, the real-time conductivity is observed. If the deviation is greater than 0.1, the opening of the circulation control valve 3 is decreased by 5%, and after waiting for 35 minutes, the real-time conductivity is observed. The deviation is calculated and compared with the target value, and this cycle is repeated.

[0053] In summary: The condensate flow rate average calculation module calculates the average of condensate flow rate data from three different locations, facilitating the averaging of condensate flow rate in the condensate outlet pipeline and improving the accuracy of the final condensate flow rate. This facilitates the feedback of the flow rate data to the ammonia addition calculation module, which calculates the ammonia addition amount based on the average condensate flow rate, thus improving the accuracy of the ammonia addition. Furthermore, the conductivity detection module 2 detects the conductivity data in the water at the condensate outlet, allowing the conductivity deviation calculation module to calculate the deviation between the target conductivity value and the actual measured conductivity data. This facilitates adjustments based on the condensate flow rate and conductivity deviation. The ammonia dosage is adjusted in different modes. When the boiler power generation load changes, i.e., the condensate flow rate changes significantly, a coarse adjustment of the ammonia dosage is required. In the coarse adjustment mode, the coarse adjustment module sends a signal to the regulating valve coefficient adjustment module to increase the opening of the circulation regulating valve 3. At this time, the ammonia pump 4 (i.e., the plunger pump) is opened to full output to cope with sudden changes in condensate flow rate. When the conductivity target threshold module is set to 9.4, if the conductivity deviation exceeds 0.2, coarse adjustment continues. If the conductivity deviation is less than 0.2, fine adjustment is performed. The fine adjustment mode specifically involves the switching module issuing an ammonia dosage control command, which is then fed back to the fine adjustment module. In the fine-tuning mode for ammonia addition, the opening of the circulation regulating valve 3 is increased by 5%. If the deviation is greater than 0.1, the opening of the circulation regulating valve 3 is decreased by 5%, and the process is repeated for 35 minutes. The real-time conductivity is observed and compared with the target value. This cycle is repeated, meaning that when the boiler power generation load is stable, the opening of the circulation regulating valve 3 is finely adjusted to gradually correct the ammonia addition, adapting to the condensate flow rate at a stable conductivity, ultimately making the conductivity infinitely close to the target value, improving the ammonia addition control effect of the condensate. An agitator 9 is installed in the ammonia storage tank 8, and multiple ammonia concentration detection modules 5 are used to detect the ammonia concentration in the ammonia water in the storage tank 8. The results are fed back to the ammonia delivery system, which compares the data with the target values ​​from the ammonia concentration target module. If the difference between the data detected by any ammonia concentration detection module 5 and the target value exceeds a set threshold, the stirrer 9 is activated to mix the ammonia water. This prevents the ammonia water from remaining stagnant for a long time, which could lead to sedimentation at the bottom and cause different ammonia concentrations at different heights, affecting the final ammonia addition reaction. The stirrer 9 continues stirring until the difference between the ammonia concentration data detected by all ammonia concentration detection modules 5 and the target value does not exceed the set threshold, at which point the stirrer 9 stops stirring.

[0054] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A condensate ammonia addition control system for a thermal power generating unit, characterized in that, include: The system includes an ammonia delivery system, a condensate monitoring terminal, an ammonia addition control terminal, and an ammonia storage terminal, all connected to the ammonia delivery system. The ammonia addition control terminal is signal-connected to both the condensate monitoring terminal and the ammonia storage terminal. The ammonia addition control terminal includes an ammonia addition pump connected to the ammonia storage terminal via a pipeline, an ammonia circulation loop assembly connected to the ammonia addition pump via a pipeline, a data receiving module II connected to the condensate monitoring terminal, a conductivity deviation calculation module connected to the data receiving module II, an ammonia addition control module connected to the ammonia circulation loop assembly and the ammonia delivery system terminal respectively, and a conductivity target threshold module and a conductivity deviation calculation module connected to the ammonia delivery system terminal.

2. The condensate ammonia addition control system for thermal power generating units according to claim 1, characterized in that, The ammonia water circulation loop assembly includes a circulation regulating valve and a regulating valve coefficient adjustment module. The circulation regulating valve is connected to the ammonia pump via a pipeline, the circulation regulating valve is connected to the condensate outlet pipeline via a pipeline, and the circulation regulating valve is connected to the ammonia water storage end via a pipeline. The regulating valve coefficient adjustment module is connected to the circulation regulating valve and the ammonia water addition control module via signal connections.

3. The condensate ammonia addition control system for thermal power generating units according to claim 1, characterized in that, The ammonia water dosage control module includes a switching module connected to the ammonia water delivery system, and a coarse adjustment module and a fine adjustment module that are respectively connected to the switching module via signals. Both the coarse adjustment module and the fine adjustment module are connected to the regulating valve coefficient adjustment module via data signals.

4. The condensate ammonia addition control system for thermal power generating units according to claim 1, characterized in that, The condensate monitoring terminal includes a condensate flow detection module, a water flow feedback logic module, an ammonia addition feedback component, a conductivity detection module, and a conductivity feedback logic module. Both the conductivity detection module and the condensate flow detection module are installed in the condensate outlet pipeline. The condensate flow detection module is signal-connected to the water flow feedback logic module, the water flow feedback logic module is signal-connected to the ammonia addition feedback component, the conductivity detection module is signal-connected to the conductivity feedback logic module, and the conductivity feedback logic module is signal-connected to the data receiving module.

5. The condensate ammonia addition control system for thermal power generating units according to claim 4, characterized in that, The ammonia addition feedback component includes a data receiving module 1, which is signal-connected to the water flow feedback logic module; a condensate flow average calculation module, which is signal-connected to the data receiving module 1; and an ammonia addition calculation module, which is signal-connected to the condensate flow average calculation module. The ammonia addition calculation module is signal-connected to the ammonia water delivery system.

6. The condensate ammonia addition control system for thermal power generating units according to claim 2, characterized in that, The ammonia storage end includes an ammonia storage tank connected to the ammonia pump and the circulation regulating valve via pipelines, an agitator installed inside the ammonia storage tank, and ammonia concentration detection modules installed on both sides of the inner cavity of the ammonia storage tank and arranged at equal intervals. The ammonia concentration detection modules are all connected to the ammonia delivery system end via data signals. The ammonia delivery system end is connected to an ammonia concentration target value module via data signals.

7. The condensate ammonia addition control system for thermal power generating units according to claim 6, characterized in that, The ammonia storage end also includes a level sensor 1 installed on the upper left side of the inner cavity of the ammonia storage tank, and a level sensor 2 installed on the lower left side of the inner cavity of the ammonia storage tank. Both the level sensor 1 and the level sensor 2 are connected to the ammonia delivery system end for signal connection.

8. A method for controlling ammonia addition to condensate in a thermal power generating unit, the method being implemented according to the ammonia addition control system for condensate in a thermal power generating unit according to any one of claims 1-7, characterized in that, include: Connect the ammonia water delivery system, condensate monitoring system, ammonia addition control system, and ammonia water storage system to establish data and control connections; install multiple condensate flow detection modules on the condensate pipeline and a conductivity detection module at the outlet pipeline; connect the ammonia addition pump to the ammonia storage tank and connect it to the ammonia storage tank through the installation of a circulation regulating valve and an ammonia water return pipeline; Multiple condensate flow detection modules detect the flow rate at different locations in real time. The flow rate data is transmitted to the data receiving module 1 via the water flow feedback logic module. The average flow rate is then processed by the condensate flow rate average calculation module and transmitted to the ammonia addition calculation module. Finally, the ammonia addition data is sent to the ammonia water delivery system. The conductivity detection module detects the conductivity of condensate in real time. The conductivity data is sent to the data receiving module 2 via the conductivity feedback logic module. The conductivity deviation calculation module calculates the deviation by combining the target value provided by the conductivity target threshold module and sends the result to the ammonia water delivery system. When the average condensate flow rate changes by a rate of 10 t / (h·min) within 3 minutes or by a change of 50 t / h within 10 minutes, the ammonia water delivery system starts the coarse adjustment mode, controls the opening of the circulation regulating valve to increase, and the ammonia pump outputs at full capacity for 35 minutes. If the average condensate flow rate continues to change at a rate >5t / (h·min), continue coarse adjustment immediately; if the conductivity deviation is ≥0.2, continue coarse adjustment; if the deviation is >2.0, increase the circulation regulating valve coefficient; if the deviation is <0.2, switch to fine adjustment mode. In fine-tuning mode, the opening of the circulation regulating valve is finely adjusted according to the conductivity deviation value, with each adjustment being ±5%. The conductivity is monitored at 35-minute intervals, and adjustments are continued or maintained based on the deviation value.

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