A closed cooling water full-automatic ammonia adding device and method

Abstract

The application discloses a kind of closed cooling water full-automatic ammonia adding device and method, device includes: PLC controller and liquid ammonia steel bottle, liquid ammonia steel bottle is communicated with closed cooling water pipeline by liquid ammonia steel bottle pipeline;Liquid ammonia steel bottle pipeline is sequentially provided with ammonia gas pressure reducing valve inlet pressure gauge, ammonia gas pressure regulating valve, ammonia gas pressure reducing valve outlet pressure gauge, ammonia gas electric regulating valve;Closed cooling water pipeline is provided with electric conductivity sensor;PLC controller is connected ammonia gas pressure reducing valve, ammonia gas pressure reducing valve inlet pressure gauge, ammonia gas pressure reducing valve outlet pressure gauge, ammonia gas electric regulating valve, electric conductivity sensor.The application is dynamically regulated by changing ammonia gas electric valve opening degree, ammonia amount is added, and the ammonia of closed cooling water is automatically regulated.

Description

Technical Field

[0001] This invention relates to the field of closed-loop cooling water chemical ammonia addition technology in power plant water-steam systems, and in particular to a fully automatic closed-loop cooling water ammonia addition device and method. Background Technology

[0002] Ammonia is the most commonly used alkalizing agent for metal corrosion prevention in thermal systems. Closed-loop ammonia dosing technology is an important component of power plant steam and water dosing systems and is the most economical and practical method to prevent feedwater corrosion of metals. By controlling the pH value of the closed-loop feedwater, and considering that conductivity is a highly reliable signal (there is a conversion formula between the conductivity and pH value of closed-loop water: pH = 8.57 + lgSC), controlling the conductivity of the closed-loop water can effectively prevent corrosion of closed-loop water pipelines and damage to the protective film on metal surfaces.

[0003] Currently, power plants use pre-prepared ammonia water for closed-loop cooling water addition, monitor the pH value of the closed-loop cooling water, and manually control the start and stop of the ammonia addition pump to add ammonia to the closed-loop cooling water system. This results in unstable water quality control indicators and some equipment corrosion. It also significantly increases the workload of the operators. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a method for adding ammonia to closed-loop cooling water, which ensures the stability of the pH (conductivity) of closed-loop cooling water during operation.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a closed-loop cooling water fully automatic ammonia dosing device, comprising: a PLC controller and a liquid ammonia cylinder, wherein the liquid ammonia cylinder is connected to a closed-loop cooling water pipeline through a liquid ammonia cylinder pipeline;

[0007] The liquid ammonia cylinder pipeline is equipped with an ammonia pressure reducing valve inlet pressure gauge, an ammonia pressure reducing valve outlet pressure gauge, and an ammonia electric regulating valve in sequence; the closed cooling water pipeline is equipped with a conductivity sensor.

[0008] The PLC controller connects to the ammonia pressure reducing valve, the ammonia pressure reducing valve inlet pressure gauge, the ammonia pressure reducing valve outlet pressure gauge, the ammonia electric regulating valve, and the conductivity sensor.

[0009] As a further improvement of the present invention, the PLC controller is connected to a touch screen.

[0010] As a further improvement of the present invention, the conductivity sensor is located downstream of the connection point between the liquid ammonia cylinder pipeline and the closed cooling water pipeline.

[0011] As a further improvement of the present invention, the liquid ammonia cylinder pipeline is also equipped with a manual ammonia valve.

[0012] Secondly, the present invention provides an ammonia addition method for a closed-loop fully automatic ammonia addition device for cooling water, comprising the following steps:

[0013] Obtain the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve;

[0014] The ammonia pressure reducing valve is dynamically adjusted to ensure that the pressure gauge at the outlet of the ammonia pressure reducing valve is at the preset value; the PLC controller compares the difference between the set expected conductivity value of the closed cooling water and the signal value collected by the conductivity sensor, and uses proportional calculation to dynamically control the ammonia electric regulating valve.

[0015] As a further improvement to the present invention, obtaining the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve further includes:

[0016] Check the pressure gauge at the inlet of the ammonia pressure reducing valve to confirm whether there is ammonia in the liquid ammonia cylinder. If the ammonia pressure is lower than the threshold, the liquid ammonia cylinder should be replaced.

[0017] As a further improvement to the present invention, the ratio calculation formula is as follows:

[0018]

[0019] in This is the proportionality coefficient. The difference between the expected value and the sampled value. To control the quantity;

[0020] For the ammonia gas electric regulating valve, the opening degree is a control quantity ,in The difference between the desired and actual conductivity of the closed-loop cooling water is determined by setting the proportional coefficient corresponding to the ammonia electric valve. The formula for calculating the proportion used is:

[0021]

[0022] As a further improvement of the present invention, the commands for dynamically controlling the ammonia electric regulating valve include:

[0023] The opening degree of the ammonia electric regulating valve, calculated using the PLC controller, is the control quantity. The opening of the ammonia gas electric regulating valve is dynamically adjusted to achieve closed-loop control of cooling water quality.

[0024] As a further improvement of the present invention, the threshold is 0.4 MPa; the preset value is 0.35 MPa.

[0025] Thirdly, the present invention provides an ammonia dosing system for a closed-loop fully automatic ammonia dosing device for cooling water, comprising:

[0026] The acquisition module is used to acquire the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve.

[0027] The adjustment module is used to dynamically adjust the ammonia pressure reducing valve to ensure that the pressure gauge at the outlet of the ammonia pressure reducing valve is at the preset value; the PLC controller compares the difference between the set expected conductivity value of the closed cooling water and the signal value collected by the conductivity sensor, uses proportional calculation, and dynamically controls the ammonia electric regulating valve.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] The device and method of this invention are simple, practical, and highly accurate, enabling precise and rapid adjustment of the ammonia dosage in closed-loop cooling water to meet the conductivity control requirements of closed-loop cooling water. Compared to current ammonia dosing systems, it eliminates the ammonia preparation section and ammonia dosing pump, using liquid ammonia cylinders, pressure reducing valves, and electric regulating valves. The ammonia dosage is dynamically adjusted based on the real-time conductivity of the closed-loop cooling water, achieving control over the water quality. This invention not only solves the problem of controlling the ammonia dosage in closed-loop cooling water but also reduces the workload of operators and improves the safety and economy of generator unit operation. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the closed-loop automatic ammonia dosing device for cooling water according to the present invention;

[0031] Figure 2 This is a flowchart of the closed-loop automatic ammonia addition method for cooling water according to the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0033] The following is in conjunction with the appendix Figure 1 and attached Figure 2 The specific embodiments of the present invention will be further described below.

[0034] like Figure 1As shown, this invention discloses a closed-loop fully automatic ammonia dosing device for cooling water, comprising a liquid ammonia cylinder pipeline connected to a closed-loop cooling water pipeline. The liquid ammonia cylinder pipeline is sequentially equipped with an ammonia manual valve 1, an ammonia pressure reducing valve inlet pressure gauge P1, an ammonia pressure reducing valve 2, an ammonia pressure reducing valve outlet pressure gauge P2, and an ammonia electric regulating valve 3. A conductivity sensor 4 is installed on the closed-loop cooling water pipeline. A PLC controller 5 is connected to the ammonia pressure reducing valve 2, the ammonia pressure reducing valve inlet pressure gauge P1, the ammonia pressure reducing valve outlet pressure gauge P2, the ammonia electric regulating valve 3, and the conductivity sensor 4. The PLC controller 5 is connected to a touch screen 6.

[0035] This invention uses a liquid ammonia cylinder as a gas source, an ammonia pressure reducing valve to dynamically adjust the outlet pressure, collects signals from a conductivity sensor of the closed cooling water, and a PLC controller obtains the opening command of the ammonia electric valve through proportional calculation. By changing the opening of the ammonia electric valve, the amount of ammonia added is dynamically adjusted, thereby realizing automatic adjustment of ammonia addition to the closed cooling water.

[0036] like Figure 1 and Figure 2 As shown, this invention also provides a method for adding ammonia to a closed-loop cooling water fully automatic ammonia adding device. The ammonia manual valve 1 is opened, and the presence of ammonia in the liquid ammonia cylinder is confirmed by checking the inlet pressure gauge P1 of the ammonia pressure reducing valve. When the ammonia pressure is less than 0.4 MPa, a prompt to replace the liquid ammonia cylinder is generated. When the ammonia pressure is greater than or equal to 0.4 MPa, the PLC controller 5 dynamically adjusts the ammonia pressure reducing valve 2 to ensure that the outlet pressure gauge P2 of the ammonia pressure reducing valve is 0.35 MPa. The PLC controller 5 compares the difference between the desired conductivity value of the closed-loop cooling water set on the touchscreen 6 and the signal value collected by the conductivity sensor 4, uses proportional calculation, and dynamically controls the ammonia electric regulating valve 3.

[0037] The formula for calculating the proportion is as follows:

[0038]

[0039] in This is the proportionality coefficient. The difference between the expected value and the sampled value. To control the quantity;

[0040] For the ammonia gas electric regulating valve, the opening degree is a control quantity ,in The difference between the desired and actual conductivity of the closed-loop cooling water is determined by setting the proportional coefficient corresponding to the ammonia electric valve. The formula for calculating the proportions used is as follows:

[0041]

[0042] The opening degree of the ammonia electric regulating valve calculated using PLC controller 5 is the control quantity. The opening of the ammonia gas electric regulating valve is dynamically adjusted to achieve closed-loop control of cooling water quality.

[0043] As attached Figure 2 As shown, the ammonia addition amount of the closed-loop cooling water is adjusted using a proportional calculation formula. By modifying the proportional coefficient, the ammonia addition amount of the closed-loop cooling water can be precisely adjusted, thus enabling the closed-loop cooling water conductivity to have an automatic control function.

[0044] The following are descriptions of other possible steps in the ammonia addition method for a closed-loop fully automatic cooling water ammonia addition system, including the following:

[0045] Obtaining the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve: The pressure of ammonia is measured by installing an inlet pressure gauge of the ammonia pressure reducing valve. The pressure gauge can convert the ammonia pressure signal into an electrical signal and transmit it to the control system.

[0046] Dynamic adjustment of the ammonia pressure reducing valve: Based on the signal from the inlet pressure gauge of the ammonia pressure reducing valve, the PLC controller can dynamically adjust the opening of the ammonia pressure reducing valve to maintain the preset value of the outlet pressure gauge. This ensures stable ammonia pressure and prevents unnecessary operational fluctuations caused by excessively rapid or slow pressurization.

[0047] The PLC controller compares the difference between the set expected conductivity value of the closed-loop cooling water and the signal value collected by the conductivity sensor: The PLC controller receives the signal from the conductivity sensor, compares the actual conductivity with the expected conductivity, and calculates the difference.

[0048] The PLC controller uses proportional calculation to dynamically control the opening of the ammonia electric regulating valve, based on the magnitude and direction of the difference, thereby controlling the flow and concentration of ammonia.

[0049] Real-time monitoring and safety protection: A real-time monitoring system should be set up throughout the process to monitor parameters such as ammonia pressure, flow rate, and concentration in real time. Once an abnormality is detected, safety protection measures should be activated immediately, such as automatically cutting off the ammonia supply and triggering an alarm.

[0050] Automatic recording and report generation: The system can automatically record relevant data for each ammonia addition operation, such as time, ammonia flow rate, conductivity, etc., and generate reports for easy subsequent query and analysis.

[0051] Intelligent Prediction and Optimization: Based on historical and real-time monitoring data, intelligent algorithms are used to predict future ammonia demand, thereby optimizing ammonia dosing plans and control parameters, and improving efficiency and accuracy.

[0052] Compatibility and scalability: The system design should consider future compatibility and scalability, facilitate integration with other devices or systems, and reserve space for future functional expansion.

[0053] User-friendly interface: Provides a user-friendly interface that facilitates monitoring, configuration, and adjustments by operators. The interface should be clear, intuitive, and easy to understand and operate.

[0054] Remote control and monitoring: Supports remote control and monitoring functions. Operators can view system status, adjust control parameters, and issue control commands on a remote terminal.

[0055] To further improve the ammonia dosing method of the closed-loop fully automatic ammonia dosing device for cooling water, and to enhance its automation, safety, and stability, the following steps can also be adopted:

[0056] Proportional control algorithm: Based on the magnitude and direction of the difference, the PLC controller uses a proportional control algorithm to calculate the opening command of the ammonia electric regulating valve. Proportional control is a common control algorithm that changes the flow rate and concentration of ammonia by adjusting the valve opening to bring it closer to the desired value.

[0057] Fuzzy logic control: To improve the accuracy and adaptability of control, fuzzy logic control methods can be employed. Fuzzy logic control can handle uncertainty and nonlinear problems, and better manage changes in differences. By matching the differences with fuzzy logic rules, more precise control commands can be generated.

[0058] Neural Network Optimization: A neural network is a computational model that simulates the structure of neurons in the human brain, possessing self-learning and adaptive capabilities. By training a neural network to identify and predict trends in the difference, the control accuracy of ammonia flow rate and concentration can be further improved. Neural networks can also be used to learn from and optimize historical data, thereby better adjusting control parameters.

[0059] Feedback control: During the adjustment process, a feedback control mechanism should be introduced to monitor the ammonia flow rate and concentration in real time and feed them back to the control system. When the actual flow rate and concentration deviate from the expected values, the PLC controller can correct them based on the feedback signal to ensure that the ammonia flow rate and concentration remain stable within the expected range.

[0060] Safety considerations: During regulation, the safety and stability of the system should be ensured. To this end, safety protection measures such as limit switches and overload protection can be implemented to prevent malfunctions or over-limit operation of the regulating valve. Simultaneously, ammonia pipelines and regulating valves should be regularly maintained and inspected to ensure their normal operation.

[0061] Automation and Intelligence: To further improve the level of automation and intelligence, artificial intelligence technologies such as machine learning and deep learning can be introduced. By training artificial intelligence models, changes in ammonia demand can be automatically identified and predicted, and control parameters can be automatically adjusted to achieve more intelligent ammonia addition operations.

[0062] Based on the above description, a third objective of this invention is to provide an ammonia dosing system for a closed-loop fully automatic ammonia dosing device for cooling water, comprising:

[0063] The acquisition module is used to acquire the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve.

[0064] The adjustment module is used to dynamically adjust the ammonia pressure reducing valve to ensure that the pressure gauge at the outlet of the ammonia pressure reducing valve is at the preset value; the PLC controller compares the difference between the set expected conductivity value of the closed cooling water and the signal value collected by the conductivity sensor, uses proportional calculation, and dynamically controls the ammonia electric regulating valve.

[0065] The steps for each module correspond to the methods described above and will not be repeated.

[0066] Unless otherwise specified, the equipment components involved in the above embodiments are all conventional equipment components, and the structural settings, working methods or control methods involved are all conventional settings, working methods or control methods in the art unless otherwise specified.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for adding ammonia to a closed-loop fully automatic ammonia dosing device for cooling water, characterized in that, The ammonia addition method includes the following steps: Obtain the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve; The presence of ammonia in the liquid ammonia cylinder is confirmed by checking the ammonia pressure at the inlet pressure gauge of the ammonia pressure reducing valve. When the ammonia pressure is less than the threshold, the liquid ammonia cylinder is prompted to be replaced. When the ammonia pressure is greater than the threshold, the ammonia pressure reducing valve is dynamically adjusted to ensure that the outlet pressure of the ammonia pressure reducing valve is at the preset value. The difference between the expected conductivity value of the closed cooling water set by the PLC controller and the signal value collected by the conductivity sensor is compared, and proportional calculation is used to dynamically control the opening command of the ammonia electric regulating valve. The formula for calculating the proportion is as follows: in, This is the proportionality coefficient. The difference between the expected value and the sampled value. To control the quantity; The opening degree of the ammonia gas electric regulating valve is used as the control quantity. ,in The difference between the desired and actual conductivity of the closed-loop cooling water is determined by setting the proportional coefficient corresponding to the ammonia gas electric regulating valve. The formula for calculating the proportion is as follows: ； The commands for dynamically controlling the opening degree of the ammonia electric regulating valve include: The opening degree of the ammonia electric regulating valve calculated by the PLC controller is used as the control quantity. The opening of the ammonia gas electric regulating valve is dynamically adjusted to achieve closed-loop control of cooling water quality.

2. The ammonia addition method of a closed-loop fully automatic ammonia addition device for cooling water according to claim 1, characterized in that, The PLC controller is connected to the touch screen.

3. The ammonia addition method of a closed-loop fully automatic ammonia addition device for cooling water according to claim 1, characterized in that, The conductivity sensor is located downstream of the junction between the liquid ammonia cylinder pipeline and the closed cooling water pipeline.

4. The ammonia addition method of a closed-loop fully automatic ammonia addition device for cooling water according to claim 1, characterized in that, The liquid ammonia cylinder pipeline is also equipped with a manual ammonia valve.

5. The ammonia addition method of a closed-loop fully automatic ammonia addition device for cooling water according to claim 1, characterized in that, The threshold is 0.4 MPa; the preset value is 0.35 MPa.

6. The ammonia addition method of a closed-loop fully automatic ammonia addition device for cooling water according to claim 1, characterized in that, The closed-loop fully automatic ammonia dosing device for cooling water includes: a PLC controller and a liquid ammonia cylinder, which is connected to the closed-loop cooling water pipeline via a liquid ammonia cylinder pipeline; The liquid ammonia cylinder pipeline is equipped with an inlet pressure gauge for an ammonia pressure reducing valve, an ammonia pressure reducing valve, an outlet pressure gauge for an ammonia pressure reducing valve, and an electric regulating valve for ammonia; the closed cooling water pipeline is equipped with a conductivity sensor. The PLC controller connects to the ammonia pressure reducing valve, the ammonia pressure reducing valve inlet pressure gauge, the ammonia pressure reducing valve outlet pressure gauge, the ammonia electric regulating valve, and the conductivity sensor.

7. An ammonia addition system for a closed-loop fully automatic ammonia addition device for cooling water, implementing the ammonia addition method of any one of claims 1 to 6, characterized in that, include: The acquisition module is used to acquire the ammonia pressure from the inlet pressure gauge of the ammonia pressure reducing valve. The adjustment module is used to dynamically adjust the ammonia pressure reducing valve to ensure that the outlet pressure of the ammonia pressure reducing valve is at the preset value. The PLC controller compares the difference between the set expected conductivity value of the closed cooling water and the signal value collected by the conductivity sensor, and uses proportional calculation to dynamically control the opening command of the ammonia electric regulating valve.

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