A method for accurately controlling the water quality of cooling water in a condenser rotor

Abstract

The present invention provides a method for precisely controlling the water quality of cooling water within a phase shifter rotor. This method utilizes a bipolar membrane reactor, a rectifier, and a control system to precisely control the water quality of the rotor cooling water. By circulating the electrode liquid between the electrode liquid chamber and the electrode liquid water tank, circulating the anion receiving liquid between the anion receiving chamber and the anion receiving box, and circulating the rotor cooling water between the rotor cooling water chamber and the raw water tank, the rotor cooling water can be introduced into the raw water tank through a bypass and then returned from the raw water tank to the rotor cooling water system. The quality of the rotor cooling water introduced into the raw water tank is monitored in real time using an online pH meter and an online conductivity meter attached to the cooling water circulation line. The rectifier controls the parameters of the direct current applied to the operating membrane stack. The present invention offers enhanced controllability and stability, enabling precise control and recycling of the rotor cooling water quality. It also eliminates the need for an ion exchanger for ion exchange desalination, resulting in low energy consumption and zero pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling water treatment for phase shifters, and more specifically to a method for accurately controlling the water quality of cooling water in a phase shifter rotor. Background Art

[0002] With the large-scale construction of my country's long-distance UHVDC transmission grid, its transmission capacity and voltage levels continue to increase, and the demand for reactive power compensation capacity is also growing. As a dynamic reactive power compensation device, the phase-shifting condenser is equivalent to the "voltage stabilizer" of the UHV grid. It can automatically and rapidly adjust reactive power, effectively improving the stability of the power system and the quality of the power supply. In the UHV AC / DC grid structure, it plays a key role in solving the problems of weak DC transmission grids at the sending end and insufficient reactive power at the receiving end.

[0003] While the reactive power support capacity of the phase regulator has been improved, it has also brought about the problem of motor heat dissipation and cooling. Water cooling has gradually become the preferred medium for cooling and dissipating heat for large phase regulators due to its advantages of high thermal conductivity, high relative density, and good heat dissipation capacity. To ensure the safe operation of the phase regulator, the water quality of the internal cooling water of the double-water internally cooled phase regulator rotor must meet two basic conditions when cooling the rotor coil: first, the internal cooling water must have sufficient insulation and low conductivity to prevent the generator winding from being grounded through the insulated water pipe at the end of the coil; second, the internal cooling water should not contain impurities that are corrosive to the hollow copper conductors and system of the generator or that can deposit and scale in the hollow copper conductors. To this end, strict internal cooling water quality standards have been formulated, stipulating water quality indicators such as conductivity, pH value, copper ion content, and dissolved oxygen content, as shown in the table below:

[0004] Serial number Physical name parameter 1 Physical state of water quality The water is transparent and pure, without mechanical impurities 2 Conductivity of cooling water in rotor (25℃) / (μs / cm) ＜5 3 pH value of cooling water in rotor (25℃) 7.0～9.0

[0005] However, during the operation of the double-water internally cooled phase regulator, the cooling water in the rotor is in direct contact with the air. Therefore, as the cooling water in the rotor runs, the dissolved oxygen and carbon dioxide content in the cooling water increase, and the pH value decreases, which leads to corrosion of the hollow copper conductors. Numerous domestic and foreign studies on the corrosion of generator cooling water systems have shown that when the pH value of the cooling water in the rotor is between 7 and 10, copper is in the stable area of ​​its potential-pH diagram. Therefore, the pH value of the cooling water in the rotor is best controlled between 7 and 9.

[0006] Currently, the treatment methods for cooling water within the rotors of condensers typically involve regular water changes, bypass low-flow water changes, and the addition of alkalizing agents to control water quality. These methods can temporarily keep the rotor cooling water quality within the specified range, but the maintenance period is short-lived and requires regular and frequent water changes, resulting in large amounts of wasted demineralized water or condensate. Furthermore, these methods have drawbacks such as frequent resin replacement, unstable pH control, chemical waste, and high maintenance costs. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention proposes a method for precisely controlling the water quality of the cooling water in the rotor of a phase-shifting machine. The method has stronger controllability, better stability and higher accuracy, and can realize precise control and recycling of the water quality of the cooling water in the rotor without adding additional chemical reagents or setting up an ion exchanger for ion exchange and desalination. While controlling the pH to meet the standard, the water quality conductivity can also be guaranteed to meet the operating requirements, with low energy consumption and no pollution.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for accurately controlling the water quality of cooling water in a phase shifter rotor is characterized by:

[0010] A bipolar membrane reactor equipped with a bipolar membrane and an anion exchange membrane is used to control the pH and conductivity of the cooling water in the phase shifter rotor. Alkali is produced online using the bipolar membrane to adjust the pH value of the cooling water in the rotor. At the same time, an anion exchange membrane is superimposed to remove carbonate ions and bicarbonate ions in the cooling water in the rotor to adjust the conductivity of the cooling water in the rotor, thereby achieving the water quality control of the cooling water in the rotor.

[0011] A bypass is installed in the rotor cooling water system of the phase shifter, through which the rotor cooling water can be led into the bipolar membrane reactor and returned to the rotor cooling water system after water quality control is completed;

[0012] In the bipolar membrane reactor, the operating membrane stack is arranged in the order of anode plate-electrode liquid chamber-bipolar membrane-anion receiving chamber-anion exchange membrane-rotor internal cooling water chamber-bipolar membrane-electrode liquid chamber-cathode plate; and in the bipolar membrane reactor: a raw water tank is provided for storing the rotor internal cooling water introduced from the bypass, and the rotor internal cooling water can be circulated between the raw water tank and the rotor internal cooling water chamber in the operating membrane stack through an internal cooling water circulation pipeline with an internal cooling water circulation pump; an anion receiving box is provided, and salt solution is added to the anion receiving box, and anion receiving liquid can be circulated between the raw water tank and the anion receiving chamber in the operating membrane stack through an anion receiving liquid circulation pipeline with an anion receiving liquid circulation pump; an electrode liquid water tank is provided, and electrode liquid is added to the electrode liquid water tank, and an electrode liquid circulation pipeline with an electrode liquid circulation pump is provided. The ring pipeline allows the electrode liquid to circulate along the path of electrode liquid water tank - electrode liquid chamber on the cathode plate side of the operating membrane stack - electrode liquid chamber on the anode plate side of the operating membrane stack - electrode liquid water tank; an online pH meter and an online conductivity meter are provided on the internal cooling water circulation pipeline, and a rectifier and a control system are configured for the bipolar membrane reactor. The anode plate and the cathode plate are connected to the positive and negative poles of the rectifier respectively. The DC parameters applied by the rectifier to the operating membrane stack are preset by the control system to control the operating temperature of the operating membrane stack to be maintained below 35°C, and the water quality of the cooling water in the rotor is monitored in real time by the online pH meter and the online conductivity meter until the pH value is 7-9 and the conductivity value is less than or equal to 5μs / cm, thereby completing water quality control. After precise control, the cooling water in the rotor can be directly returned from the raw water tank through a bypass to the cooling water tank of the phase regulator for reuse.

[0013] The working process of the bipolar membrane reactor of the present invention is as follows:

[0014] ①:

[0015] ②: In the raw water tank: HCO3 - +OH - →H2O+CO3 2-

[0016] o:

[0017] The characteristics of the precise control method of the cooling water quality in the condenser rotor are:

[0018] When the pH value monitored by the online pH meter is less than 7 or the conductivity value monitored by the online conductivity meter is greater than 5μs / cm, the bipolar membrane reactor and the rectifier are controlled by the control system to start operation, and the bipolar membrane reactor is used to produce alkali online, and the pH value of the cooling water in the rotor is adjusted to 7.0-9.0. At the same time, an anion exchange membrane is superimposed to remove carbonate ions and bicarbonate ions, reducing the conductivity value to less than or equal to 5μs / cm;

[0019] When the pH value monitored by the online pH meter is greater than 9 or the conductivity value monitored by the online conductivity meter is less than 5μs / cm, the bipolar membrane reactor and the rectifier are controlled to stop running through the control system.

[0020] When the control system controls the bipolar membrane reactor and the liquid supply system to start operation, the corresponding circulation pump is first turned on, and then the rectifier is turned on; when the control system controls the bipolar membrane reactor and the liquid supply system to stop operation, the rectifier is first turned off, and then the corresponding circulation pump is turned off.

[0021] The membrane voltage applied by the rectifier to the cathode and anode of the bipolar membrane reactor is 5-20V, and the current density is 0.2-10A / m 2 . More specifically:

[0022] If the conductivity of the cooling water in the rotor introduced into the raw water tank through the bypass is greater than 10μs / cm or the pH value is less than 5, the voltage of the rectifier is 20V;

[0023] If the conductivity of the cooling water in the rotor introduced into the raw water tank through the bypass is 9-10μs / cm or the pH value is 5-6, the voltage of the rectifier is 15V;

[0024] If the conductivity of the cooling water introduced into the rotor from the raw water tank through the bypass is 8-9μs / cm or the pH value is 6-6.5, the voltage of the rectifier is 10V;

[0025] If the conductivity of the cooling water in the rotor introduced into the raw water tank through the bypass is 7-8μs / cm or the pH value is 6.5-7, the voltage of the rectifier is 5V.

[0026] The cooling water in the rotor is the water quality of the phase shifter cooling water that has changed after operation, with a pH value of less than 7 and a conductivity value of greater than 5μs / cm.

[0027] The internal cooling water circulation pipeline, the anion receiving liquid circulation pipeline, and the electrode liquid circulation pipeline are all equipped with electronically controlled valves on the inlet and outlet sides of the matching circulation pump and the liquid inlet side of the bipolar membrane reactor, and a heat exchanger and a precision filter are arranged between the liquid outlet side of the circulation pump and the liquid inlet side of the bipolar membrane reactor; each circulation pump, each electronically controlled valve, heat exchanger, online pH meter, online conductivity meter, and rectifier are respectively connected to and controlled by the control system. When the operating membrane stack temperature exceeds 35°C, the heat exchanger can be used for cooling.

[0028] The anion exchange membrane is a homogeneous ion exchange membrane.

[0029] The salt solution added into the anion receiving box is 0.01M sodium sulfate solution.

[0030] The electrode liquid added to the electrode liquid water tank is 0.3M sodium sulfate solution.

[0031] Through the electrode liquid circulation pipeline, the liquid outlet side of the electrode liquid water tank is connected to the liquid inlet side of the electrode liquid circulation pump, the liquid inlet side is connected to the liquid outlet side of the bipolar membrane reactor, the liquid outlet side of the electrode liquid circulation pump is connected to the liquid inlet side of the cathode plate side electrode liquid chamber in the operating membrane stack of the bipolar membrane reactor, the liquid outlet side of the cathode plate side electrode liquid chamber is connected to the liquid inlet side of the anode plate side electrode liquid chamber, and the liquid outlet side of the anode plate side electrode liquid chamber is connected to the liquid inlet side of the electrode liquid water tank;

[0032] The liquid outlet side of the anion receiving box is connected to the liquid inlet side of the anion receiving liquid circulation pump through the anion receiving liquid circulation pipeline, the liquid inlet side is connected to the liquid outlet side of the anion receiving chamber in the operating membrane stack, and the liquid outlet side of the anion receiving liquid circulation pump is connected to the liquid inlet side of the anion receiving chamber;

[0033] The liquid outlet side of the raw water tank is connected to the liquid inlet side of the internal cooling water circulation pump through the internal cooling water circulation pipeline, and the liquid outlet side receives the liquid from the rotor internal cooling water chamber in the operating membrane stack at the liquid inlet side, and the liquid outlet side of the internal cooling water circulation pump is connected to the liquid inlet side of the rotor internal cooling water chamber;

[0034] The bypass is installed between the raw water tank of the bipolar membrane reactor and the rotor internal cooling water system of the phase shifter.

[0035] The electrode liquid chamber, anion receiving chamber and cooling water chamber in the rotor on the anode plate side have liquid inlet and outlet on the same side, and the liquid inlet and outlet are on different sides. The liquid inlet and outlet directions of the electrode liquid chamber on the cathode plate side are set in the opposite direction to those of the electrode liquid chamber on the anode plate side.

[0036] Compared with the existing technology, the present invention realizes precise control of the cooling water quality in the rotor through the bipolar membrane reactor, rectifier and control system. The beneficial effects are reflected in:

[0037] 1. The entire process does not use ion exchange resin, does not add additional chemical reagents, and does not produce waste resin or solid waste residue;

[0038] 2. It can stabilize the pH value of the cooling water in the rotor at 7-9 and simultaneously control the conductivity value to be less than or equal to 5μs / cm, which can realize the recycling of the cooling water in the rotor and save water resources;

[0039] 3. The bipolar membrane reactor has a high degree of integration and does not require additional ion exchange desalination equipment to control water conductivity. It saves space, has low energy consumption, is simple in method, easy to operate and control, and does not cause environmental pollution. It is an ideal process suitable for promotion and application.

[0040] In summary, the present invention is used to replace existing processes such as regular water exchange treatment, ion exchange desalination, and drug addition alkalization treatment. Compared with the traditional use of commercial sodium hydroxide to adjust the pH value of the rotor cooling water, the present invention adopts bipolar membrane technology and uses a rectifier to adjust the voltage and current values ​​applied to the operating membrane stack to adjust the alkali production amount and alkali production rate. The system integrates an online conductivity meter and an online pH meter, which can monitor the water quality parameters of the rotor cooling water introduced from the rotor cooling water chamber into the raw water tank online, and adjust the voltage and current applied by the rectifier to the operating membrane stack in real time online through the control system. The pH index of the cooling water in the rotor is made more controllable, more stable, more accurate, and copper corrosion is slowed down. The slowdown in copper corrosion allows the copper ion content in the cooling water in the rotor to be maintained at a low level for a long time, and the service life of the ion exchange resin is correspondingly extended, thereby avoiding the need to use ion exchange resin for desalination, reducing operation and maintenance costs, and overcoming the shortcomings of the existing treatment methods for cooling water in the rotor of a phase shifter, such as complicated processes, frequent resin replacement, unstable pH value control, inaccurate reagent addition, and high operation and maintenance costs. The system is streamlined with a small number of devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a process flow chart of the present invention;

[0042] Figure 2 It is a schematic diagram of the arrangement structure of the operating membrane stack in a bipolar membrane reactor.

[0043] Figure 3 The schematic diagram shows the structure in which the rotor cooling water flows between the rotor cooling water system of the phase shifter and the bipolar membrane reactor of the present invention through a bypass.

[0044] In the picture:

[0045] 1 bipolar membrane reactor; 111 anode plate; 112 anode plate side electrode liquid chamber; 113 bipolar membrane; 114 anion receiving chamber; 115 anion exchange membrane; 116 rotor inner cooling water chamber; 117 cathode plate side electrode liquid chamber; 118 cathode plate;

[0046] 121 raw water tank; 122 internal cooling water circulation pipeline; 123 internal cooling water circulation pump; 124 online pH meter; 125 online conductivity meter

[0047] 131 anion receiving box; 132 anion receiving solution circulation pipeline; 133 anion receiving solution circulation pump;

[0048] 141 electrode liquid water tank; 142 electrode liquid circulation pipeline; 143 electrode liquid circulation pump;

[0049] 15 heat exchanger; 16 precision filter;

[0050] 2 rectifier; 3 control system;

[0051] 4 bypass. DETAILED DESCRIPTION

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0053] Example 1

[0054] The bipolar membrane is a new type of ionic composite membrane made of a cationic membrane and a negative membrane. The characteristic of this membrane is that under the action of the DC electric field applied by the rectifier, the H2O between the cathode and cathode membrane composite layers dissociates into H + and OH - And pass through the anorectal membrane and cation membrane respectively, as H + and OH - Ion source.

[0055] Please refer to Figures 1 to 3 The precise water quality control system for cooling water within the phase-shifting rotor of this embodiment includes a bipolar membrane reactor, a rectifier, and a control system. The bipolar membrane reactor is a single unit. The bipolar membrane is specifically model Astom BP-1, and the anion exchange membrane is specifically model Aston AMV.

[0056] A 0.01M sodium sulfate solution was added to the anion receiving box; a 0.3M sodium sulfate solution was added to the electrode liquid water tank; and the rectifier voltage was preset to 50V and the current to 20mA through the control system.

[0057] When the pH value of the cooling water in the rotor introduced into the raw water tank reaches 6.9, the control system controls the bipolar membrane reactor and the rectifier to start operation. The circulation pumps are first turned on, and then the rectifier is turned on. The voltage is displayed as 50V and the current is displayed as 10mA. After starting operation, the bipolar membrane begins to generate hydroxide ions under the action of the current. At the same time, carbonate and bicarbonate ions pass through the anion membrane into the anion receiving chamber. The pH value of the cooling water in the rotor begins to rise. When the pH value reaches 9, the system stops running, the rectifier is turned off, and the circulation pump stops.

[0058] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A method for accurately controlling the water quality of cooling water in a phase shifter rotor, characterized by: A bipolar membrane reactor equipped with a bipolar membrane and an anion exchange membrane is used to control the pH and conductivity of the cooling water in the phase shifter rotor. Alkali is produced online using the bipolar membrane to adjust the pH value of the cooling water in the rotor. At the same time, an anion exchange membrane is superimposed to remove carbonate ions and bicarbonate ions in the cooling water in the rotor to adjust the conductivity of the cooling water in the rotor, thereby achieving the water quality control of the cooling water in the rotor. A bypass is installed in the rotor cooling water system of the phase shifter, through which the rotor cooling water can be led into the bipolar membrane reactor and returned to the rotor cooling water system after water quality control is completed; In the bipolar membrane reactor, the operating membrane stack is arranged in the order of anode plate-electrode liquid chamber-bipolar membrane-anion receiving chamber-anion exchange membrane-rotor internal cooling water chamber-bipolar membrane-electrode liquid chamber-cathode plate; and in the bipolar membrane reactor: a raw water tank is provided for storing rotor internal cooling water introduced from a bypass, and the rotor internal cooling water can be circulated between the raw water tank and the rotor internal cooling water chamber in the operating membrane stack through an internal cooling water circulation pipeline with an internal cooling water circulation pump; an anion receiving box is provided, and salt solution is added to the anion receiving box, and anion receiving liquid can be circulated between the raw water tank and the anion receiving chamber in the operating membrane stack through an anion receiving liquid circulation pipeline with an anion receiving liquid circulation pump; an electrode liquid water tank is provided, and the electrode liquid water tank is supplied with a charge of ... Electrode liquid is added inside, and the electrode liquid is circulated along the path of the electrode liquid water tank-the electrode liquid chamber on the cathode plate side of the operating membrane stack-the electrode liquid chamber on the anode plate side of the operating membrane stack-the electrode liquid water tank through the electrode liquid circulation pipeline with an electrode liquid circulation pump; an online pH meter and an online conductivity meter are provided on the internal cooling water circulation pipeline, and a rectifier and a control system are configured for the bipolar membrane reactor. The anode plate and the cathode plate are connected to the positive and negative poles of the rectifier respectively. The direct current parameters applied by the rectifier to the operating membrane stack are preset by the control system to control the operating temperature of the operating membrane stack to be maintained below 35°C, and the water quality of the cooling water in the rotor is monitored in real time by the online pH meter and the online conductivity meter until the pH value is 7-9 and the conductivity value is less than or equal to 5μs / cm, thereby completing water quality control; When the pH value monitored by the online pH meter is less than 7 or the conductivity value monitored by the online conductivity meter is greater than 5μs / cm, the bipolar membrane reactor and the rectifier are controlled by the control system to start operation, and the bipolar membrane reactor is used to produce alkali online, and the pH value of the cooling water in the rotor is adjusted to 7.0-9.

0. At the same time, an anion exchange membrane is superimposed to remove carbonate ions and bicarbonate ions, reducing the conductivity value to less than or equal to 5μs / cm; When the pH value monitored by the online pH meter is greater than 9 or the conductivity value monitored by the online conductivity meter is less than 5μs / cm, the bipolar membrane reactor and the rectifier are controlled to stop running through the control system.

2. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: When the control system controls the bipolar membrane reactor and the liquid supply system to start operation, the corresponding circulation pump is first turned on, and then the rectifier is turned on; when the control system controls the bipolar membrane reactor and the liquid supply system to stop operation, the rectifier is first turned off, and then the corresponding circulation pump is turned off.

3. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The membrane voltage applied by the rectifier to the cathode and anode of the bipolar membrane reactor is 5-20V, and the current density is 0.2-10A / m 2 .

4. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The cooling water in the rotor is the water quality of the phase shifter cooling water that has changed after operation, with a pH value of less than 7 and a conductivity value of greater than 5μs / cm.

5. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The internal cooling water circulation pipeline, the anion receiving liquid circulation pipeline, and the electrode liquid circulation pipeline are all equipped with electronically controlled valves on the inlet and outlet sides of the matching circulation pump and the liquid inlet side of the bipolar membrane reactor, and a heat exchanger and a precision filter are arranged between the liquid outlet side of the circulation pump and the liquid inlet side of the bipolar membrane reactor; each circulation pump, each electronically controlled valve, heat exchanger, online pH meter, online conductivity meter, and rectifier are respectively connected to and controlled by the control system.

6. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The anion exchange membrane is a homogeneous ion exchange membrane.

7. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The salt solution added into the anion receiving box is 0.01M sodium sulfate solution.

8. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The electrode liquid added to the electrode liquid water tank is 0.3M sodium sulfate solution.

9. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 is characterized by: The anode plate side electrode liquid chamber, anion receiving chamber, and rotor internal cooling water chamber have liquid inlet and outlet on the same side, and the liquid inlet and outlet are on different sides. The liquid inlet and outlet directions of the cathode plate side electrode liquid chamber are set opposite to those of the anode plate side electrode liquid chamber.

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