Cold end intelligent operation and maintenance method

Abstract

The present application relates to the technical field of power plant cold end intelligent technology, and discloses a kind of cold end intelligent operation and maintenance method, obtains cold end real-time operation data, including condenser operation data, cooling tower operation data and water treatment system data;Condenser operation data includes the rotating speed of heat transfer enhancement device, condenser inlet and outlet water temperature.When the rotating speed of heat transfer enhancement device is less than the rated rotating speed under the real-time flow of circulating water, the system will automatically inspect the power consumption of water pump, the total amount of circulating water and the turbidity of circulating water, so as to realize real-time monitoring and early warning of cold end operation state.Through monitoring and analysis of the power consumption of water pump, the total amount of circulating water and the turbidity of circulating water, it is judged whether the cold end operation state is normal.If abnormal condition is found, the system will immediately issue a warning signal for timely treatment.According to the monitoring result and the warning signal, the operation state of the cold end can be optimized and adjusted, the operation efficiency can be improved, and the energy consumption can be reduced.

Description

Technical Field

[0001] This invention relates to the field of intelligent technology for the cold end of power plants, and specifically to an intelligent operation and maintenance method for the cold end. Background Technology

[0002] The cold-end system is a crucial component of a generator set, comprising subsystems such as the low-pressure cylinder body and its regenerative steam extraction system, exhaust port and condenser system, circulating water system, sealing system and vacuum system, and cooling tower system. The core purpose of this system is to convert turbine exhaust into condensate, allowing the water to be reheated into steam for continuous power generation. The operational quality of the cold-end system directly affects the generator set's vacuum level, and the turbine vacuum level or back pressure of large generator sets has a significant impact on their energy consumption and economic efficiency. Research data shows that when the back pressure exceeds the critical back pressure, for every 1 kPa increase in back pressure, coal consumption for power generation increases by 2-3 g / kWh. Therefore, the operational goal of the cold-end system is to achieve the optimal vacuum level or the lowest possible back pressure under given circulating water system power consumption conditions.

[0003] During generator unit operation, the performance of the cold-end system is affected by various subsystems. These effects can include: higher circulating water temperature due to cooling tower performance degradation; reduced circulating water flow due to circulating water system performance degradation; increased condenser terminal temperature due to condenser system performance degradation; and increased air partial pressure in the back pressure due to sealing system performance degradation. However, in actual operation and management, operators often struggle to understand the impact and extent of these factors, particularly the relative degrees of influence of different factors on the vacuum. This makes it difficult, if not impossible, for them to make correct judgments and improvements, leading to significant blind spots in the management of the cold-end system and ultimately resulting in unavoidable losses. Summary of the Invention

[0004] The present invention aims to provide a method for intelligent operation and maintenance of cold end systems, which adjusts the operating parameters of each system in the cold end system according to real-time operating data in order to achieve intelligent operation of the cold end system.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a cold-end intelligent operation and maintenance method, which acquires real-time operating data of the cold end, including condenser operating data, cooling tower operating data, and water treatment system data;

[0006] The condenser operating data includes the rotational speed of the enhanced heat exchange device and the condenser inlet and outlet water temperatures; the water treatment system data includes the real-time flow rate of circulating water.

[0007] If the speed of the enhanced heat exchange device is less than the rated speed under the real-time flow of circulating water, the power consumption of the water pump, the total amount of circulating water, and the turbidity of the circulating water will be automatically checked.

[0008] The principle of this solution is as follows: In practical applications, this invention acquires real-time operating data of the cold end, including condenser operating data, cooling tower operating data, and water treatment system data, as well as the rotational speed of the enhanced heat exchanger and the rated rotational speed under real-time circulating water flow. When the rotational speed of the enhanced heat exchanger is less than the rated rotational speed under real-time circulating water flow, the system automatically checks the power consumption of the water pump, the total circulating water volume, and the turbidity of the circulating water, thereby achieving real-time monitoring and early warning of the cold end's operating status. This helps improve the operating efficiency of the cold end and reduce energy consumption, achieving energy conservation and emission reduction. By monitoring and analyzing the power consumption of the water pump, the total circulating water volume, and the turbidity of the circulating water, the system determines whether the cold end's operating status is normal. If an abnormality is detected, the system will immediately issue an early warning signal for timely handling. Based on the monitoring results and early warning signals, the operating status of the cold end can be optimized and adjusted to improve operating efficiency and reduce energy consumption.

[0009] The advantages of this solution are: it enables real-time monitoring and early warning of the cold-end operating status, allowing for timely detection of anomalies and the implementation of corresponding measures to prevent equipment damage and downtime. By automatically monitoring the power consumption of the water pumps, the total volume of circulating water, and the turbidity of the circulating water, a more comprehensive understanding of the cold-end operating status can be obtained, providing a basis for optimization and adjustments. This solution offers high flexibility and scalability, allowing for customization and expansion to meet the needs of different occasions and application scenarios.

[0010] Preferably, as an improvement, the water treatment system data includes water hardness, total alkalinity, and COD content. The water treatment system data may also include water pH, nitrate content, etc. This data reflects the overall water quality, allows for understanding and monitoring of the water treatment system's operation, enables timely adjustment and optimization of system parameters, and ensures stable operation of the water treatment system and compliance with water quality standards.

[0011] Preferably, as an improvement, the cooling tower operating data includes an approximation degree, the approximation degree setpoint being less than 5.5 degrees Celsius. The approximation degree refers to the difference between the water temperature after cooling by the cooling tower and the ambient wet-bulb temperature.

[0012] During the operation of a cooling tower, the approximation degree is a very important parameter. It represents the difference between the water temperature after cooling by the cooling tower and the ambient wet-bulb temperature. Typically, the approximation degree setting is less than 5.5 degrees Celsius.

[0013] In practical applications, the approximation degree directly affects the cooling effect and energy consumption of a cooling tower. If the approximation degree is too high, it indicates insufficient cooling, requiring an increase in the cooling water flow rate or replacement with a cooling tower with a larger surface area. Conversely, if the approximation degree is too low, it indicates excessive cooling, requiring a reduction in the cooling water flow rate or adjustment of the cooling tower's operating parameters. By monitoring the approximation degree in real time, the operating parameters of the cooling tower can be adjusted promptly, ensuring optimized cooling effect and energy consumption. Furthermore, by comparing the approximation degree data over different time periods, the operating status and performance changes of the cooling tower can be analyzed.

[0014] Preferably, as an improvement, when the approximation degree is greater than 5.5 degrees Celsius, the cooling tower water spray density is automatically checked. If the cooling tower water spray density is less than the maximum value, the cooling tower water spray density is increased to the maximum value. When the temperature threshold of the approximation degree is exceeded, the system will automatically activate the function of checking the cooling tower water spray density. If the check finds that the cooling tower water spray density is less than its maximum allowable value, the system will automatically increase the cooling tower water spray density to the maximum value. This operational design can ensure that the cooling tower can obtain effective cooling effect in high-temperature environments, thereby ensuring its normal operation and extending its service life. At the same time, this automated detection and adjustment can also greatly reduce the frequency of manual intervention, improving work efficiency and accuracy.

[0015] Preferably, as an improvement, when the approximation degree is greater than 5.5 degrees Celsius, the cooling tower water spray density is automatically checked. If the cooling tower water spray density is at its maximum value, a cooling tower warning is issued and automatically recorded.

[0016] When the temperature approaches 5.5 degrees Celsius, the automatic inspection system will monitor the water spray density of the cooling tower. Once the water spray density reaches its maximum value, the system will issue a cooling tower warning and automatically record relevant information. When the cooling tower's water spray density reaches its maximum value, it indicates that the cooling tower can no longer handle the additional load. At this point, the system will issue a cooling tower warning, reminding users to take measures to prevent equipment damage or malfunction. Simultaneously with issuing the warning, the system will automatically record relevant information for subsequent analysis and processing. Using automatic inspection ensures the normal operation of equipment and the smooth progress of the production process, reducing the risk of human intervention and misjudgment.

[0017] Preferably, as an improvement, real-time cold source loss is obtained based on the real-time cold water temperature and hot water temperature of the circulating water, as well as the real-time flow rate of the circulating water. A decline in cooling tower performance leads to a higher circulating water temperature, and a decline in the performance of the circulating water system results in a decrease in the circulating water flow rate.

[0018] Preferably, as an improvement, the enhanced heat exchange device includes a fixed joint and a spiral ribbon, the spiral ribbon being inserted into the heat exchange tubes of the condenser and driven to rotate by the flow rate of circulating water; the fixed joint of the spiral ribbon is equipped with a speed sensor for measuring the rotational speed of the spiral ribbon.

[0019] Preferably, as an improvement, the spiral band of the enhanced heat exchange device irregularly scrapes the heat exchange tube wall of the condenser; and automatically inspects the tube wall vibration state and inner wall collision state of the condenser's heat exchange tubes.

[0020] Preferably, as an improvement, the rotational speed of the enhanced heat exchanger is obtained. If the rotational speed of a single enhanced heat exchanger is less than the lower limit speed, the vibration state of the tube wall and the collision state of the inner wall of the heat exchange tube where the enhanced heat exchanger is located are automatically inspected. Attached Figure Description

[0021] Figure 1 A schematic diagram of the structure of adding an enhanced heat exchange device to the array heat exchange tubes of the condenser in an embodiment of the present invention. Detailed Implementation

[0022] The following detailed description illustrates the specific implementation method:

[0023] The temperature difference between the inlet and outlet of the cooling water in the condenser is defined as the temperature rise. When the turbine exhaust volume is constant, an increase in the condenser temperature rise indicates insufficient cooling water, leading to a decrease in condenser vacuum. When the circulating water volume does not change significantly, the temperature rise increases with the increase of load.

[0024] The condenser terminal temperature difference refers to the difference between the saturation temperature at condenser pressure and the cooling water outlet temperature. Subcooling refers to the presence of some non-condensable gases in a condenser under high vacuum, regardless of the method used. Due to steam resistance and the presence of non-condensable gases, coupled with structural and operational defects in the condenser, the condensate temperature may fall below the saturation temperature corresponding to the exhaust pressure.

[0025] The formula for calculating the heat transfer coefficient of a condenser is: h = Q / (A × ΔT). Where h represents the heat transfer coefficient, Q represents the heat flow rate, A represents the heat transfer area, and ΔT represents the temperature difference during heat conduction. The heat transfer coefficient h reflects the amount of heat exchanged per unit area per unit time in the condenser; the heat flow rate Q represents the amount of heat transferred per unit time in the condenser; the heat transfer area A refers to the heat exchange area inside the condenser; and the temperature difference ΔT refers to the difference between two different temperatures during the heat transfer process inside the condenser. This formula is used to calculate the heat transfer coefficient of a condenser under specific conditions.

[0026] Real-time back pressure P refers to the pressure of steam condensing inside the condenser. This pressure can be calculated by the difference between the pressure of steam entering the condenser and the pressure of steam flowing out of the condenser after condensation. The specific formula is: Back pressure = Inlet steam pressure - Outlet steam pressure.

[0027] Factors typically affecting the heat transfer coefficient of a condenser include: the cleanliness of the cooling tubes, the condenser cooling area, the condenser subcooling, the condenser heat load, the cooling water inlet temperature, and the cooling water flow rate. Additionally, fouling on the water side of the condenser also affects its heat transfer coefficient. Since the cooling water is in direct contact with the external environment, its quality may be poor, leading to impurities accumulating and forming scale and fouling on the inner walls of the pipes. This hinders direct contact between the water and the pipe walls, increasing thermal resistance. This thermal resistance can be expressed as the thermal conductivity of the fouling layer multiplied by the thickness of the fouling layer divided by the length of the pipe. As the thickness of the fouling layer increases, the thermal resistance also increases, significantly impacting heat transfer and noticeably reducing the heat transfer coefficient. Furthermore, the thickness of the condensate film on the steam side also affects heat transfer efficiency. Conventional surface condensers in power plants are generally designed for film condensation. Steam releases its latent heat of vaporization upon encountering the cooler pipe walls and condenses into water. The condensate does not immediately leave the wall but adheres to the surface of the heat exchange tubes, forming a water film. This water film hinders direct contact between steam and the pipe wall, increasing thermal resistance and causing a decrease in the heat transfer coefficient and efficiency. Clearly, the thicker the water film, the greater its impact on heat transfer.

[0028] The present invention provides an intelligent operation and maintenance method for the cold end, which acquires real-time operating data of the cold end, including condenser operating data, cooling tower operating data, and water treatment system data.

[0029] The condenser operating data includes the rotational speed of the enhanced heat exchange device and the condenser inlet and outlet water temperatures; the water treatment system data includes the real-time flow rate of circulating water, water hardness, total alkalinity, and COD content.

[0030] The data from the water treatment system may also include water pH, nitrate content, and other parameters. This data reflects the overall water quality, allows for understanding and monitoring of the system's operation, and enables timely adjustment and optimization of system parameters to ensure stable operation and compliance with water quality standards.

[0031] For example, water hardness can be set to no more than 300 mg, total alkalinity to no more than 300 mg, COD content to no more than 15 mg, and turbidity to no more than 5 NTU.

[0032] Real-time cold source loss is determined based on the real-time cold and hot water temperatures and the real-time flow rate of the circulating water. Degraded cooling tower performance leads to higher cold water temperatures in the circulating water system, and this degraded performance in the circulating water system results in a decrease in the circulating water flow rate.

[0033] If the speed of the enhanced heat exchange device is less than the rated speed under the real-time flow of circulating water, the power consumption of the water pump, the total amount of circulating water, and the turbidity of the circulating water will be automatically checked.

[0034] Cooling tower operating data includes the approximation degree, which is set to be less than 5.5 degrees Celsius. The approximation degree refers to the difference between the water temperature after cooling by the cooling tower and the ambient wet-bulb temperature. Approximation degree is a crucial parameter during cooling tower operation. It represents the difference between the water temperature after cooling by the cooling tower and the ambient wet-bulb temperature. Typically, the approximation degree is set to less than 5.5 degrees Celsius. In practical applications, the magnitude of the approximation degree directly affects the cooling tower's cooling effect and energy consumption. If the approximation degree is too high, it indicates insufficient cooling effect, requiring an increase in the cooling water flow rate or replacement with a cooling tower with a larger surface area. Conversely, if the approximation degree is too low, it indicates excessive cooling effect, requiring a reduction in the cooling water flow rate or adjustment of the cooling tower's operating parameters. By monitoring the approximation degree value in real time, the cooling tower's operating parameters can be adjusted promptly to ensure optimized cooling effect and energy consumption. Furthermore, by comparing the approximation degree data over different time periods, the operating status and performance changes of the cooling tower can be analyzed.

[0035] When the temperature approach threshold exceeds 5.5 degrees Celsius, the system automatically checks the cooling tower's water spray density. If the water spray density is lower than the maximum value, the system increases the water spray density to the maximum. When this temperature threshold is exceeded, the system automatically activates the water spray density check. If the check finds that the water spray density is lower than the maximum allowable value, the system automatically increases the water spray density to the maximum value. This operational design ensures that the cooling tower achieves effective cooling in high-temperature environments, thus guaranteeing its normal operation and extending its service life. Simultaneously, this automated detection and adjustment significantly reduces the frequency of manual intervention, improving work efficiency and accuracy.

[0036] When the approach temperature exceeds 5.5 degrees Celsius, the automatic monitoring system checks the cooling tower's water spray density. If the water spray density reaches its maximum value, a cooling tower warning is issued, and the information is automatically recorded. When the approach temperature exceeds 5.5 degrees Celsius, the automatic monitoring system will monitor the cooling tower's water spray density. Once the water spray density reaches its maximum value, the system will issue a cooling tower warning and automatically record relevant information. When the cooling tower's water spray density reaches its maximum value, it indicates that the cooling tower can no longer handle the additional load. At this time, the system will issue a cooling tower warning, reminding users to take measures to prevent equipment damage or malfunction. Simultaneously with issuing the warning, the system will also automatically record relevant information for subsequent analysis and processing.

[0037] The enhanced heat exchange device includes a fixed joint and a spiral ribbon. The spiral ribbon extends deep into the heat exchange tubes of the condenser and is driven to rotate by the flow rate of the circulating water, making it a passive power device. Installing the enhanced heat exchange device in each heat exchange tube of the condenser, the device operates without external power. The spiral ribbon rotates continuously and rapidly within the heat exchange tubes, reaching speeds of 300-1800 r / min. This enhanced fluid rotation within the heat exchange tubes disrupts the scale formation mechanism, moving beyond the traditional passive cleaning and descaling concept to active scale prevention. Simultaneously, it enhances heat exchange, significantly increasing the condenser's heat transfer coefficient (K-value) by over 20%. After using the enhanced heat exchange device, the water flow inside the condenser tubes becomes turbulent, forming a rotating flow, which prolongs the time the water flows through a unit length; it also destroys the boundary stagnant layer, causing the central fluid and the tube wall fluid to undergo displacement, generating secondary swirling flow, etc., so that the cleanliness coefficient of the heat exchange tubes is maintained at a high level of over 0.85, which is very beneficial for reducing the condenser terminal temperature difference and improving the heat exchange efficiency.

[0038] The fixed joint of the spiral ribbon is equipped with a speed sensor to measure the rotational speed of the spiral ribbon. The spiral ribbon of the enhanced heat exchange device irregularly scrapes the heat exchanger tube walls of the condenser; it automatically inspects the tube wall vibration and inner wall collision status of the condenser's heat exchanger tubes. Additionally, a magnet is added to the end of the spiral ribbon; as the spiral ribbon rotates, the magnetic field strength information of the magnet is acquired, thereby obtaining the center deflection position information of the spiral ribbon and evaluating the degree of tilt of the spiral ribbon.

[0039] If the rotational speed of a single enhanced heat exchanger is less than the lower limit, the vibration state of the tube wall and the collision state of the inner wall of the heat exchanger tube where the enhanced heat exchanger is located will be automatically checked.

[0040] For cold-end systems, the core focus is on the back pressure-heat / power correction curve to accurately calculate the optimal economic operating vacuum.

[0041] △q=f(PK); △q is the heat consumption correction value, and PK is the turbine back pressure.

[0042] In actual operation, load and circulating water parameters are constantly changing, which affects back pressure. Correlation functions and corrections need to be considered. For example, the impact of condensate flow rate, initial temperature, and initial pressure on heat consumption corrections is not a simple addition, but rather a superposition and coupling relationship, requiring calculation using large amounts of operational data from different units. The function is:

[0043] △q=f(PK,DC,t0,P0)

[0044] Due to the influence of ambient temperature and the operation mode of the circulating water pump, the flow rate and temperature of the circulating water, which are the external working conditions of the turbine cold end, will change constantly. In addition to heat loss correction for the steam inlet parameters, heat loss correction should also be applied to the flow rate and temperature of the circulating water.

[0045] △q=f(PK,DC,t0,P0,NF,NW...)

[0046] In practical applications, this invention acquires real-time operating data at the cold end, including condenser operating data, cooling tower operating data, and water treatment system data, as well as the rotational speed of the enhanced heat exchanger and the rated speed under real-time circulating water flow. This data can be directly integrated online into the power plant's DCS system. By combining this data with turbine operating data, the system comprehensively assesses the rotational speed of the enhanced heat exchanger, the vibration state of the heat exchange tube walls, and the collision state of the inner walls, thereby comprehensively reducing the terminal temperature difference and subcooling, and improving thermal efficiency.

[0047] Monitoring the rotational speed and impact vibration status of the enhanced heat exchanger provides effective feedback on the condenser's operating status and allows for the timely detection of potential safety issues, thus effectively preventing malfunctions. Regarding rotational speed monitoring, abnormal rotational speeds of the enhanced heat exchanger may be due to poor fluid flow within the condenser or fouling on the heat exchanger surface. Real-time monitoring and alarm functions for these speeds allow for timely detection and resolution of these problems, ensuring the normal operation of the condenser. Furthermore, monitoring impact vibration is another crucial indicator of the condenser's operating status. When fluid flow within the condenser becomes unstable or cracks appear on the heat exchanger surface, the impact vibration status often changes. Real-time monitoring and alarm functions for these impact vibrations allow for timely detection and resolution of these issues, preventing more serious condenser failures. In conclusion, monitoring the rotational speed and impact vibration status of the enhanced heat exchanger effectively provides feedback on the condenser's operating status, allows for the timely detection and resolution of potential problems, and ensures the stable operation of the condenser.

[0048] When the speed of the enhanced heat exchanger is lower than the rated speed at the real-time flow rate of the circulating water, the system automatically monitors the power consumption of the water pump, the total volume of circulating water, and the turbidity of the circulating water, thereby achieving real-time monitoring and early warning of the cold-end operating status. This helps improve the operating efficiency of the cold end and reduce energy consumption, achieving energy conservation and emission reduction. By monitoring and analyzing the power consumption of the water pump, the total volume of circulating water, and the turbidity of the circulating water, the system determines whether the cold-end operating status is normal. If an abnormality is detected, the system will immediately issue an early warning signal for timely handling. Based on the monitoring results and early warning signals, the operating status of the cold end can be optimized and adjusted to improve operating efficiency and reduce energy consumption.

[0049] This system enables real-time monitoring and early warning of the cold-end operating status, allowing for timely detection of anomalies and the implementation of corresponding measures to prevent equipment damage and downtime. By automatically monitoring pump power consumption, total circulating water volume, and circulating water turbidity, a more comprehensive understanding of the cold-end operating status can be obtained, providing a basis for optimization and adjustments. This solution offers high flexibility and scalability, allowing for customization and expansion to meet the needs of different occasions and application scenarios.

[0050] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention. In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" 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; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A cold-end intelligent operation and maintenance method, characterized in that, Includes the following steps: Acquire real-time operating data of the cold end, including condenser operating data, cooling tower operating data, and water treatment system data; the cooling tower operating data includes the approximation degree, and the approximation degree set value is less than 5.5 degrees Celsius; The condenser operating data includes the rotational speed of the enhanced heat exchange device and the condenser inlet and outlet water temperatures; the water treatment system data includes the real-time flow rate of circulating water. The enhanced heat exchange device includes a fixed joint and a spiral ribbon. The spiral ribbon extends into the heat exchange tubes of the condenser and is driven to rotate by the flow rate of the circulating water. The fixed joint of the spiral ribbon is equipped with a speed sensor to measure the rotational speed of the spiral ribbon. If the speed of the enhanced heat exchange device is less than the rated speed under the real-time flow of circulating water, the power consumption of the water pump, the total amount of circulating water, and the turbidity of the circulating water will be automatically checked. The spiral band of the enhanced heat exchange device irregularly scrapes the heat exchange tube wall of the condenser; it automatically inspects the vibration state of the heat exchange tube wall and the collision state of the inner wall of the condenser. The rotational speed of the enhanced heat exchanger is obtained. If the rotational speed of a single enhanced heat exchanger is less than the lower limit, the vibration state of the tube wall and the collision state of the inner wall of the heat exchange tube where the enhanced heat exchanger is located are automatically checked.

2. The cold-end intelligent operation and maintenance method according to claim 1, characterized in that: The water treatment system data includes water hardness, total alkalinity, and COD content.

3. The cold-end intelligent operation and maintenance method according to claim 1, characterized in that: When the approximation degree is greater than 5.5 degrees Celsius, the cooling tower water spray density is automatically checked. If the cooling tower water spray density is less than the maximum value, the cooling tower water spray density is increased to the maximum value.

4. The cold-end intelligent operation and maintenance method according to claim 1, characterized in that: When the approximation degree is greater than 5.5 degrees Celsius, the cooling tower water spray density is automatically checked. If the cooling tower water spray density is at its maximum value, a cooling tower warning is issued and automatically recorded.

5. The cold-end intelligent operation and maintenance method according to claim 1, characterized in that: Real-time cold source loss is obtained based on the real-time cold water temperature and hot water temperature of the circulating water, and the real-time flow rate of the circulating water.

6. The cold-end intelligent operation and maintenance method according to claim 1, characterized in that: Obtain the center deflection position information of the spiral ribbon in the enhanced heat exchange device and evaluate the degree of inclination of the spiral ribbon.

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