Method for accurately regulating and controlling water quality of cold water in rotor of phase modifier

Abstract

The invention provides a method for accurately regulating and controlling the water quality of cold water in a rotor of a phase modifier, which comprises the following steps: accurately regulating and controlling the water quality of the cold water in the rotor through a bipolar membrane reactor, a rectifier and a control system; the anion receiving liquid circularly circulates between the anion receiving chamber and the anion receiving box, the rotor internal cooling water circularly circulates between the rotor internal cooling water chamber and the raw water tank, and the phase modifier rotor internal cooling water can be introduced into the raw water tank through a bypass and returns to the rotor internal cooling water system from the raw water tank; the water quality of rotor internal cooling water introduced into the raw water tank is monitored in real time through an online pH meter and an online conductivity meter of an internal cooling water circulation pipeline, and parameters of applying direct current to an operation membrane stack are regulated and controlled through a rectifier. According to the invention, the controllability is stronger, the stability is better, the water quality of the cold water in the rotor can be accurately regulated and controlled and recycled, an ion exchanger is not required to be arranged for ion exchange desalination, the energy consumption is low, and the pollution is avoided.

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 ultra-high voltage direct current transmission grid, its transmission capacity and voltage level are constantly increasing, and the capacity demand for reactive power compensation is also increasing. As a dynamic reactive power compensation device, the phase regulator is equivalent to the "voltage stabilizer" of the ultra-high voltage grid. It has the function of automatically and quickly adjusting reactive power, which can effectively improve the stability of the power system and improve the power supply quality of the system. In the ultra-high voltage AC and DC grid structure, it plays a key role in solving the problems of weak DC transmission sending-end grid and insufficient reactive power of receiving-end grid.

[0003] While the reactive power support capacity of the phase regulator has been improved, it has also brought about the problem of heat dissipation and cooling of the motor. Water cooling has gradually become the preferred medium for cooling and heat dissipation of large phase regulators due to its advantages of high thermal conductivity, large relative density and good heat dissipation capacity. In order to ensure the safety of the phase regulator operation, the water quality of the internal cooling water of the double-water internally cooled phase regulator rotor must meet the two most 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 systems of the generator or that can be deposited and scaled 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 Water physical state 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-shifting machine, 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 in the rotor increase, and the pH value decreases, thereby causing corrosion of the hollow copper conductor. Numerous studies on the corrosion of the cooling water system in generators at home and abroad 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] At present, the treatment methods for cooling water in the rotor of a phase-converting machine usually adopt regular water replacement, bypass small flow water replacement and alkalization agent treatment to control water quality. These methods can control the water quality of the cooling water in the rotor within the standard range for a short time, but the maintenance time is short and regular and frequent water replacement is required, resulting in a large amount of desalted water or condensate waste; and there are disadvantages such as frequent resin replacement, unstable pH value control, waste of agents, and high operation and maintenance costs. Summary of the invention

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

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

[0009] A method for accurately controlling the water quality of cooling water in a phase-converter rotor, which 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 rotor of the phase shifter. 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 jointly achieving the control of the water quality of the cooling water in the rotor.

[0011] A bypass is added to 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 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 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, 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, the operating temperature of the operating membrane stack is controlled 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, to complete the water quality control, and the rotor cooling water after precise control can be directly returned from the raw water tank through the 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 water quality of the cooling water in the phase shifter rotor are also:

[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, and the conductivity value is reduced 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 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 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 rotor inner cooling water 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 electric control 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 electric control valve, heat exchanger, online pH meter, online conductivity meter, and rectifier are respectively connected to and controlled by the control system, and 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 into 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 bipolar membrane reactor operating membrane stack, 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] Through the anion receiving liquid circulation pipeline, the liquid outlet side of the anion receiving box is connected to the liquid inlet side of the anion receiving liquid circulation pump, 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] Through the internal cooling water circulation pipeline, the liquid outlet side of the raw water tank is connected to the liquid inlet side of the internal cooling water circulation pump, and the liquid outlet from the rotor internal cooling water chamber in the operating membrane stack is received 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 on different sides. The liquid inlet and outlet directions of the electrode liquid chamber on the cathode plate side are set opposite to those of the electrode liquid chamber on the anode plate side.

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

[0037] 1. The whole 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, so as to 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 there is no need to set up an ion exchange desalination equipment to control the water conductivity. It saves space, has low energy consumption, is simple in method, easy to operate and control, and will not cause environmental pollution. It is an ideal process method suitable for promotion and application;

[0040] In summary, the present invention is used to replace the existing processes such as regular water replacement treatment, ion exchange desalination, and dosing 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 adjusts the voltage and current values ​​applied to the operating membrane stack through a rectifier to adjust the alkali production amount and alkali production rate. The system integrates an online conductivity meter and an online pH meter, and can monitor the water quality parameters of the rotor cooling water introduced from the rotor cooling water chamber into the raw water tank online. The voltage and current applied by the rectifier to the operating membrane stack are adjusted 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 of copper corrosion enables 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 the operation and maintenance cost investment, and overcoming the shortcomings of the existing treatment methods for cooling water in the rotor of phase shifters, such as complicated processes, frequent resin replacement, unstable pH value control, inaccurate reagent addition, and high operation and maintenance costs. The number of devices is small, making the system streamlined. 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 It is a structural schematic diagram of the circulation of rotor cooling water 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 figure:

[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] 4Bypass. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] Example 1

[0054] The bipolar membrane is a new type of ion composite membrane made of a cation membrane and a cathode 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 anion membrane and the 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 in the phase-converting machine rotor of this embodiment includes a bipolar membrane reactor, a rectifier, and a control system. The bipolar membrane reactor is a unit. In the bipolar membrane reactor, the specific model of the bipolar membrane is astom BP-1, and the specific model of the anion exchange membrane is aston AMV.

[0056] Add 0.01M sodium sulfate solution to the anion receiving box; add 0.3M sodium sulfate solution to the electrode liquid water tank; preset the rectifier voltage 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 is 6.9, the control system controls the bipolar membrane reactor and the rectifier to start operation, each circulation pump is turned on first, and then the rectifier is turned on, the voltage displays 50V, and the current displays 10mA; after starting operation, the bipolar membrane begins to generate hydroxide ions under the action of the current, and at the same time, the carbonate and bicarbonate ions pass through the anion membrane into the anion receiving chamber, and 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] Although the 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 present invention, and that the scope of the present 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-converting 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 rotor of the phase shifter. 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 jointly achieving the control of the water quality of the cooling water in the rotor. A bypass is added to 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 the 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 salt solution. Electrode liquid is added inside, and the electrode liquid can 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 through an 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, 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, the operating temperature of the operating membrane stack is controlled 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.

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 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, and the conductivity value is reduced 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.

3. The method for accurately controlling the water quality of cooling water in a phase condenser rotor according to claim 1 or 2, characterized in that: 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.

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 rectifier applies a membrane voltage of 5-20V to the cathode and anode of the bipolar membrane reactor, and a current density of 0.2-10A / m 2 .

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 rotor inner cooling water 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.

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 internal cooling water circulation pipeline, the anion receiving liquid circulation pipeline, and the electrode liquid circulation pipeline are all equipped with electric control valves on the liquid 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 electric control valve, heat exchanger, online pH meter, online conductivity meter, and rectifier are respectively connected to and controlled by the control system.

7. The precise water quality control system for cooling water in the phase condenser rotor according to claim 1 is characterized by: The anion exchange membrane is a homogeneous ion exchange membrane.

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 salt solution added into the anion receiving box is 0.01M 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 electrode liquid added into the electrode liquid water tank is 0.3M sodium sulfate solution.

10. The precise water quality control system for cooling water in a phase condenser rotor according to claim 1 is characterized by: The electrode liquid chamber on the anode plate side, the anion receiving chamber, and the cooling water chamber in the rotor have liquid inlet and outlet on the same side, and the liquid inlet and outlet directions of the electrode liquid chamber on the cathode plate side are set opposite to those of the electrode liquid chamber on the anode plate side.

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