Indirect air cooling tower anti-freezing regulation and control system and method thereof

Abstract

The invention discloses an indirect air cooling tower anti-freezing regulation and control system and a method thereof.The indirect air cooling tower anti-freezing regulation and control system comprises a roller shutter curtain, a temperature sensor and a control assembly, the roller shutter curtain is arranged at an air inlet of a cooling triangle of an air cooling tower, and the temperature sensor is arranged on a finned tube of the cooling triangle of the air cooling tower; the control assembly comprises a signal collecting box, a PLC module and a DCS module which are connected, the signal collecting box is used for collecting temperature signals and actual opening signals of the roller shutter curtain, the PLC module is used for processing the signals and generating opening signals of the roller shutter curtain to be adjusted, and the DCS module is used for receiving the opening signals of the roller shutter curtain to be adjusted and controlling the opening of the roller shutter curtain through the actuator. According to the system, the height of the roller shutter curtain is accurately adjusted in real time according to the outlet water temperature of the finned tube, low-back-pressure operation of a unit is maintained while freezing prevention is achieved, the power generation efficiency is improved, and energy conservation and environmental protection of a power plant are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power and energy engineering, and in particular to an indirect air cooling tower antifreeze control system and method thereof. Background Art

[0002] With the continuous growth of energy demand, power plants in coal-rich and water-scarce regions play an important role in power supply. As a key energy-saving technology in power plants, indirect air-cooling towers play an important role in reducing water consumption. However, due to the low winter temperatures in some areas, the finned tube bundles of indirect air-cooling towers are prone to freezing, affecting the normal operation and safe production of power plants.

[0003] At present, the industry generally adopts the method of adjusting the opening of the shutters to prevent freezing of indirect air cooling towers. However, the shutters have problems such as air leakage and loose closure, resulting in poor antifreeze effect and unable to meet actual needs.

[0004] In addition, the existing indirect air cooling tower antifreeze system usually adjusts the antifreeze device opening by monitoring the outlet water temperature of the sector. In order to ensure the antifreeze effect, it is necessary to maintain a high outlet water temperature, which correspondingly leads to an increase in the operating back pressure of the unit, thereby increasing the unit's power generation coal consumption and operating costs. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0006] To this end, an embodiment of the present invention proposes an indirect air cooling tower antifreeze control system to solve the problems of poor antifreeze effect and high operating cost in the prior art.

[0007] The indirect air cooling tower antifreeze control system of the embodiment of the present invention comprises:

[0008] A rolling shutter curtain, which is arranged at the air inlet of the cooling triangle of the air cooling tower, and is used to adjust the air inlet volume of the cooling triangle;

[0009] A temperature sensor is provided on the fin tube of the cooling triangle of the air cooling tower, and is used to monitor the outlet water temperature of the fin tube;

[0010] A control component, the control component includes a signal acquisition box, a PLC module and a DCS module, the signal acquisition box is connected to the rolling shutter curtain and the temperature sensor, the signal acquisition box is used to collect temperature signals and actual opening signals of the rolling shutter curtain, the PLC module is connected to the signal acquisition box, the PLC module is used to process signals and generate rolling shutter curtain opening signals to be adjusted, the DCS module is connected to the PLC module, the DCS module is used to receive rolling shutter curtain opening signals to be adjusted and control the opening of the rolling shutter curtain through an actuator.

[0011] The indirect air-cooling tower antifreeze control system of the embodiment of the present invention accurately adjusts the height of the rolling shutter curtain in real time according to the outlet water temperature of the fin tube, maintains low back pressure operation of the unit while preventing freezing, improves power generation efficiency, and is beneficial to energy conservation and environmental protection of power plants.

[0012] In some embodiments, the area of ​​the rolling shutter curtain matches the area of ​​the cooling triangle air inlet, and the rolling shutter curtain can be adjusted between fully open and fully closed of the cooling triangle air inlet.

[0013] In some embodiments, there are multiple rolling shutter curtains, and the multiple rolling shutter curtains correspond one-to-one to each cooling triangle of the air cooling tower.

[0014] In some embodiments, the temperature sensor is arranged on the water outlet pipe wall of the fin tube at the outermost side of the cooling triangle of the air cooling tower.

[0015] In some embodiments, there are a plurality of temperature sensors, and the plurality of temperature sensors are spaced apart and distributed along the length direction of the fin tube.

[0016] An embodiment of the present invention further provides an antifreeze control method for an indirect air-cooling tower, and the antifreeze control method is used for the indirect air-cooling tower antifreeze control system described in any one of the above embodiments.

[0017] The indirect air cooling tower antifreeze control method of the embodiment of the present invention comprises:

[0018] The temperature sensor is used to monitor the outlet water temperature of the outermost fin tube of each cooling triangle in real time;

[0019] Transmit the temperature signal and the actual opening degree signal of the rolling shutter to the PLC module;

[0020] The PLC module processes the signal and generates a shutter curtain opening signal to be adjusted;

[0021] Transmit the shutter curtain opening signal to be adjusted to the DCS module;

[0022] The DCS module controls the opening of the roller shutter curtain through the actuator.

[0023] In some embodiments, when the PLC module processes the temperature signal, the temperature sensor is calibrated using a standard source of known temperature, the output signal of the sensor at the standard temperature is recorded, and the temperature value corresponding to the standard signal is set or input in the program of the PLC module, and the calibration formula satisfied is:

[0024] T=α·V+b

[0025] Where T is the temperature, V is the voltage output of the temperature sensor, and a and b are calibration coefficients.

[0026] In some embodiments, the ambient temperature T is collected by monitoring the ambient temperature T env 、Humidity env Meteorological data is used as a reference for antifreeze control;

[0027] The heat dissipation efficiency of the finned tube is linearly related to the ambient temperature. The ambient temperature has a direct influence on the outlet water temperature T of the finned tube. out The influence of satisfies the relationship:

[0028] T out =T in -k1·(T env -T base )

[0029] Among them, T in is the cooling water temperature entering the fin tube, k1 is the heat dissipation efficiency coefficient, T base Base ambient temperature;

[0030] Introducing the humidity coefficient k2, the effect of humidity on the outlet water temperature of the finned tube satisfies the relationship:

[0031] T out =T in -k1·(T env -T base )-k2·(H ene -H base )

[0032] Among them, H env is the ambient humidity, H base is the base humidity;

[0033] The anti-freeze control strategy determines the opening degree O of the rolling shutter curtain according to the combination of ambient temperature and humidity, sets a critical condition, and adjusts the opening degree of the rolling shutter curtain when the combination of ambient temperature and humidity exceeds the condition:

[0034]

[0035] Among them, O max is the maximum opening of the roller shutter curtain, O min is the minimum opening, Tth and H th are the thresholds of ambient temperature and humidity respectively, and k3 and k4 are adjustment coefficients.

[0036] In some embodiments, the actual opening of the roller shutter curtain and the outlet water temperature of the cooling triangle satisfy the relationship:

[0037]

[0038] Among them, k is the sensitivity coefficient of the outlet water temperature to the change of the shutter curtain opening, which indicates the response degree of temperature change to the change of opening degree, and b is a constant term used to adjust the temperature when the opening degree is close to zero. min The rate of temperature change.

[0039] In some embodiments, the sensitivity coefficient of the outlet water temperature changing with the opening of the rolling shutter curtain is determined by experimental method, a series of opening points of the rolling shutter curtain are selected, all variables are kept constant, the opening of the rolling shutter curtain is changed, and for each predetermined rolling shutter curtain opening, the outlet water temperature of the cooling triangular fin tube bundle is monitored in real time. Linear regression analysis is used to fit the relationship between the opening and the outlet water temperature, and its slope is the sensitivity coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of an indirect air cooling tower antifreeze control system according to an embodiment of the present invention.

[0041] Reference numerals:

[0042] 1-indirect air cooling tower, 2-temperature sensor, 3-rolling shutter, 4-PLC module, 5-DCS module, 6-first collection box, 7-second collection box, 8-actuator. DETAILED DESCRIPTION

[0043] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0044] The indirect air cooling tower antifreeze control system according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0045] like Figure 1 As shown, the indirect air cooling tower antifreeze control system of the embodiment of the present invention includes: a roller shutter curtain 3, a temperature sensor 2 and a control component.

[0046] The indirect air cooling tower 1 is mainly composed of an upper tower tube and a radiator cooling triangle finned tube bundle at the bottom. The shutter curtain 3 is arranged at the air inlet of the cooling triangle, and the shutter curtain 3 is used to adjust the air inlet volume of the cooling triangle. The temperature sensor 2 is arranged on the finned tube of the cooling triangle, and the temperature sensor 2 is used to monitor the outlet water temperature of the finned tube.

[0047] The control component includes a signal acquisition box, a PLC module 4 and a DCS module 5. The signal acquisition box is connected to the roller shutter curtain 3 and the temperature sensor 2. The signal acquisition box is used to collect temperature signals and actual opening signals of the roller shutter curtain 3. The PLC module 4 is connected to the signal acquisition box. The PLC module 4 is used to process signals and generate a roller shutter curtain opening signal to be adjusted (that is, a new roller shutter curtain opening signal). The DCS module 5 is connected to the PLC module 4. The DCS module 5 is used to receive the roller shutter curtain opening signal to be adjusted, and control the opening of the roller shutter curtain 3 through the actuator 8, thereby achieving the purpose of antifreeze.

[0048] Optionally, the signal collection box includes a first collection box 6 and a second collection box 7, the first collection box 6 is used to collect the actual opening signal of the rolling shutter curtain 3, and the second collection box 7 is used to collect the temperature signal.

[0049] It is understandable that the temperature sensor 2 monitors the water outlet temperature of the outermost fin tube of each cooling triangle in real time, and sends the monitored temperature signal to the signal acquisition box. At the same time, the opening signal of the roller shutter curtain 3 is also collected and transmitted to the signal acquisition box.

[0050] The signal acquisition box transmits the collected temperature signal and shutter curtain opening signal to the PLC module 4. The PLC module 4 processes these signals and calculates the required shutter curtain 3 opening according to the preset algorithm and logic to respond to the current temperature conditions.

[0051] The PLC module 4 generates new opening instructions for the roller shutter curtain 3 based on the processed data. These instructions are intended to adjust the opening of the roller shutter curtain 3 to ensure that the fin tube bundle does not freeze and maintain the unit running under low back pressure.

[0052] The new opening instruction of the rolling shutter curtain 3 is transmitted to the actuator 8 through the DCS module 5. The actuator 8 controls the motor of the rolling shutter curtain 3 according to the received instruction, thereby adjusting the opening of the rolling shutter curtain 3.

[0053] The system also includes a feedback mechanism for monitoring the actual opening of the roller shutter curtain 3 and comparing it with the target opening set in the PLC module 4. If there is a difference, the system will make corresponding adjustments to ensure that the opening of the roller shutter curtain 3 is consistent with the target opening.

[0054] The indirect air-cooling tower antifreeze control system of the embodiment of the present invention accurately adjusts the height of the roller shutter curtain 3 in real time according to the outlet water temperature of the fin tube, maintains low back pressure operation of the unit while preventing freezing, improves power generation efficiency, and is beneficial to energy conservation and environmental protection of power plants.

[0055] In some embodiments, the area of ​​the shutter curtain 3 matches the area of ​​the cooling triangle air inlet, and the shutter curtain 3 can be adjusted between fully open and fully closed at the cooling triangle air inlet. That is, the shutter curtain 3 can completely cover the cooling triangle air inlet and can be adjusted to any opening, including fully open and fully closed. When there is no risk of freezing, the shutter curtain 3 can be completely retracted upwards without affecting the air intake of the air cooling tower 1.

[0056] Furthermore, there are multiple rolling shutter curtains 3, which correspond one to one with each cooling triangle of the air cooling tower 1. The opening of the rolling shutter curtains 3 can be controlled as a whole, in groups or individually, and the adjustment method is flexible.

[0057] In some embodiments, the temperature sensor 2 is arranged on the outermost fin tube outlet pipe wall of the cooling triangle of the air cooling tower 1, and is arranged at the lowest water temperature, so as to accurately monitor the fin tube outlet water temperature.

[0058] Furthermore, there are multiple temperature sensors 2, which are spaced apart along the length direction of the fin tube. In other words, a plurality of temperature sensors 2 are arranged on the water outlet pipe wall of the outermost fin tube of each cooling triangle, and the lowest temperature is taken as the input value of the control component.

[0059] The following describes an antifreeze control method for an indirect air cooling tower according to an embodiment of the present invention. The antifreeze control method is used for an antifreeze control system for an indirect air cooling tower in any of the above embodiments.

[0060] The indirect air cooling tower antifreeze control method of the embodiment of the present invention comprises:

[0061] Step 1: Use temperature sensor 2 to monitor the water outlet temperature of the outermost fin tube of each cooling triangle in real time, and ensure that the monitoring point is located at the lowest water temperature to accurately capture the risk of freezing. Install a wind speed sensor to monitor the wind speed at the air inlet of the cooling triangle to assist in determining the impact of environmental conditions on the cooling effect. Collect meteorological data such as ambient temperature and humidity as a reference for antifreeze control.

[0062] Step 2: The temperature sensor 2, wind speed sensor and shutter curtain opening signals are transmitted to the PLC module 4, and the PLC module 4 pre-processes the received signals, including filtering and denoising, unit conversion and signal calibration.

[0063] Step 3: PLC module 4 processes the signal using a preset algorithm (such as fuzzy control, PID control, etc.) based on the temperature, wind speed and environmental data. Based on the processed data, combined with historical operating data and historical freezing events, trend analysis and prediction are performed. PLC module 4 generates a new shutter curtain opening signal that takes into account the current temperature conditions, environmental factors and predicted freezing risks.

[0064] Step 4: The new shutter curtain opening signal is transmitted to the DCS module 5 . The DCS module 5 verifies the received signal and generates a control instruction to prepare the actuator 8 for action.

[0065] Step 5: The DCS module 5 controls the opening of the shutter curtain 3 through the actuator 8 (such as a motor controller). After the opening is adjusted, the actual opening of the shutter curtain 3 and the change in the outlet water temperature of the cooling triangle are fed back through the sensor. The PLC module 4 performs closed-loop control based on the feedback information and fine-tunes the opening of the shutter curtain 3 to ensure the best antifreeze effect.

[0066] Step 6: Continuously monitor the outlet water temperature of the cooling triangle, the opening of the roller shutter 3, and environmental conditions to ensure that the system operates in the best state. Regularly analyze the operating data, optimize the antifreeze control strategy, and improve the system's adaptability and antifreeze efficiency. When a system abnormality or failure is detected, it automatically switches to safe mode and issues an alarm for timely processing.

[0067] Therefore, through this refined and expanded control method, the antifreeze system of the indirect air-cooling tower 1 can respond to different operating conditions and environmental changes more accurately and intelligently, thereby improving the antifreeze effect and system reliability.

[0068] In some embodiments, calibration is performed when the PLC module 4 processes the temperature signal to ensure that the readings of the sensor and the PLC module 4 match the actual temperature value, thereby ensuring the accuracy of the readings.

[0069] Use a standard source of known temperature (such as a constant temperature bath) to calibrate the temperature sensor 2, record the output signal (such as voltage or current) of the sensor at the standard temperature, and set or input the temperature value corresponding to the standard signal in the program of the PLC module 4.

[0070] For example, if a thermocouple sensor is used, the calibration formula that needs to be entered is:

[0071] T=a·V+b

[0072] Where T is temperature, V is the voltage output of temperature sensor 2, and a and b are calibration coefficients.

[0073] In some embodiments, the ambient temperature T is collected by monitoring the ambient temperature T env 、Humidity env The meteorological data is used as a reference for antifreeze control, and these data are directly related to the heat dissipation efficiency and freezing risk of the air cooling tower 1.

[0074] The heat dissipation efficiency of the finned tube is linearly related to the ambient temperature. The ambient temperature has a direct influence on the outlet water temperature T of the finned tube. out The influence of satisfies the relationship:

[0075] Tout =T in -k1·(T env -T base )

[0076] Among them, T in is the cooling water temperature entering the fin tube, k1 is the heat dissipation efficiency coefficient, T base Base ambient temperature.

[0077] It should be noted that humidity can affect the heat dissipation efficiency of the air cooling tower 1, because high humidity will reduce the heat dissipation capacity.

[0078] Therefore, the humidity coefficient k2 is introduced, and the influence of humidity on the outlet water temperature of the fin tube satisfies the relationship:

[0079] T out =T in -k1·(T env -T base )-k2·(H env -H base )

[0080] Among them, H env is the ambient humidity, H base is the base humidity.

[0081] The antifreeze control strategy determines the opening O of the roller shutter curtain 3 according to the combination of ambient temperature and humidity, sets a critical condition, and when the combination of ambient temperature and humidity exceeds the condition, adjusts the opening of the roller shutter curtain 3 to prevent freezing:

[0082]

[0083] Among them, O max is the maximum opening of the roller shutter curtain 3, O min is the minimum opening, T th and H th are the thresholds of ambient temperature and humidity respectively, and k3 and k4 are adjustment coefficients.

[0084] The coefficients (k1, k2, k3, k4) in these formulas need to be determined based on actual operating data and historical freezing events to optimize the antifreeze control strategy. Through such a mathematical model, antifreeze measures can be formulated more scientifically to ensure that the air cooling tower 1 can operate safely and efficiently under harsh environmental conditions.

[0085] In some embodiments, the relationship between the actual opening of the roller shutter curtain 3 and the outlet water temperature of the cooling triangle can be expressed by the following formula. For example, if this relationship is linear, that is, the larger the opening, the lower the outlet water temperature, it can be expressed as:

[0086] T out =Tbase -k·(OO min )

[0087] Among them, T out is the outlet water temperature of the cooling triangle; T base is the outlet water temperature when there is no risk of freezing, that is, the outlet water temperature when the roller shutter curtain 3 is fully opened; k is the sensitivity coefficient of the outlet water temperature to the change in the opening degree of the roller shutter curtain 3, indicating the degree of response of the temperature change to the change in the opening degree; O is the actual opening degree of the roller shutter curtain 3; O min It is the minimum opening of the roller shutter curtain 3, corresponding to the opening when the antifreeze effect is maximum.

[0088] If the relationship is nonlinear, it can be expressed as:

[0089]

[0090] Where b is a constant term, which is used to adjust the opening when it is close to 0. min The rate of temperature change.

[0091] In some embodiments, the sensitivity coefficient k of the outlet water temperature changing with the opening degree of the roller shutter curtain 3 is determined by an experimental method.

[0092] Step 1: Select a series of opening points of the roller shutter curtain 3, which should cover the range from fully closed to fully open; ensure that the experiment is carried out under stable environmental conditions to reduce the impact of other factors on the outlet water temperature; keep all other variables (such as cooling water flow, inlet temperature, ambient temperature and humidity, etc.) constant and only change the opening of the roller shutter curtain 3.

[0093] Step 2: For each predetermined opening of the roller shutter curtain 3, the temperature sensor 2 is used to monitor the outlet water temperature of the cooling triangular fin tube bundle in real time, and the outlet water temperature data corresponding to each opening is recorded.

[0094] Step 3: Use a chart or table to record the opening and the corresponding outlet water temperature data, and use linear regression analysis to fit the relationship between the opening and the outlet water temperature. Linear regression is used to find the best fitting line, and its slope is the sensitivity coefficient k.

[0095] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0096] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0097] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0098] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0099] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0100] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. An indirect air cooling tower antifreeze control system, characterized in that: include: A rolling shutter curtain, which is arranged at the air inlet of the cooling triangle of the air cooling tower, and is used to adjust the air inlet volume of the cooling triangle; A temperature sensor is provided on the fin tube of the cooling triangle of the air cooling tower, and is used to monitor the outlet water temperature of the fin tube; A control component, the control component includes a signal acquisition box, a PLC module and a DCS module, the signal acquisition box is connected to the rolling shutter curtain and the temperature sensor, the signal acquisition box is used to collect temperature signals and actual opening signals of the rolling shutter curtain, the PLC module is connected to the signal acquisition box, the PLC module is used to process signals and generate rolling shutter curtain opening signals to be adjusted, the DCS module is connected to the PLC module, the DCS module is used to receive the rolling shutter curtain opening signals to be adjusted and control the opening of the rolling shutter curtain through an actuator.

2. The indirect air cooling tower antifreeze control system according to claim 1, characterized in that: The area of ​​the rolling shutter curtain matches the area of ​​the cooling triangle air inlet, and the rolling shutter curtain can be adjusted between fully open and fully closed of the cooling triangle air inlet.

3. The indirect air cooling tower antifreeze control system according to claim 2, characterized in that: There are multiple rolling shutter curtains, and the multiple rolling shutter curtains correspond one-to-one to each cooling triangle of the air cooling tower.

4. The indirect air cooling tower antifreeze control system according to claim 1, characterized in that: The temperature sensor is arranged on the water outlet pipe wall of the finned tube at the outermost side of the cooling triangle of the air cooling tower.

5. The indirect air cooling tower antifreeze control system according to claim 4, characterized in that: There are a plurality of temperature sensors, and the plurality of temperature sensors are distributed at intervals along the length direction of the fin tube.

6. An indirect air cooling tower antifreeze control method, characterized in that: The antifreeze control method is used for the indirect air cooling tower antifreeze control system according to any one of claims 1 to 5, and the antifreeze control method comprises: The temperature sensor is used to monitor the outlet water temperature of the outermost fin tube of each cooling triangle in real time; Transmit the temperature signal and the actual opening degree signal of the rolling shutter to the PLC module; The PLC module processes the signal and generates a shutter curtain opening signal to be adjusted; Transmit the shutter curtain opening signal to be adjusted to the DCS module; The DCS module controls the opening of the roller shutter curtain through the actuator.

7. The indirect air cooling tower antifreeze control method according to claim 6, characterized in that: When the PLC module processes the temperature signal, use a standard source with a known temperature to calibrate the temperature sensor, record the output signal of the sensor at the standard temperature, and set or input the temperature value corresponding to the standard signal in the program of the PLC module. The calibration formula that meets the requirements is: T=a·V+b Where T is the temperature, V is the voltage output of the temperature sensor, and a and b are calibration coefficients.

8. The indirect air cooling tower antifreeze control method according to claim 7, characterized in that: The environmental temperature T is monitored and collected by the environmental detection sensor env 、Humidity env Meteorological data is used as a reference for antifreeze control; The heat dissipation efficiency of the finned tube is linearly related to the ambient temperature. The ambient temperature has a direct influence on the outlet water temperature T of the finned tube. out The influence of satisfies the relationship: T out =T in -k1·(T env -T base ) Among them, T in is the cooling water temperature entering the fin tube, k1 is the heat dissipation efficiency coefficient, T base Base ambient temperature; Introducing the humidity coefficient k2, the effect of humidity on the outlet water temperature of the finned tube satisfies the relationship: T out =T in -k1·(T env -T base )-k2·(H env -H base ) Among them, H env is the ambient humidity, H base is the base humidity; The anti-freeze control strategy determines the opening degree O of the rolling shutter curtain according to the combination of ambient temperature and humidity, sets a critical condition, and adjusts the opening degree of the rolling shutter curtain when the combination of ambient temperature and humidity exceeds the condition: Among them, O max is the maximum opening of the roller shutter curtain, O min is the minimum opening, T th and H th are the thresholds of ambient temperature and humidity respectively, and k3 and k4 are adjustment coefficients.

9. The indirect air cooling tower antifreeze control method according to claim 8, characterized in that: The actual opening of the rolling shutter curtain and the outlet water temperature of the cooling triangle satisfy the relationship: Among them, k is the sensitivity coefficient of the outlet water temperature to the change of the shutter curtain opening, which indicates the response degree of temperature change to the change of opening degree, and b is a constant term used to adjust the temperature when the opening degree is close to zero. min The rate of temperature change.

10. The indirect air cooling tower antifreeze control method according to claim 9, characterized in that: The sensitivity coefficient of the outlet water temperature to the change of the roller shutter curtain opening is determined by experimental method. A series of roller shutter curtain opening points are selected, all variables are kept constant, and the opening of the roller shutter curtain is changed. For each predetermined roller shutter curtain opening, the outlet water temperature of the cooling triangular fin tube bundle is monitored in real time. Linear regression analysis is used to fit the relationship between the opening and the outlet water temperature, and its slope is the sensitivity coefficient.

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