CN1354548A

CN1354548A - Cooling water non-chemical on-line cleaning method for power generator and phase regulator and its cleaning system

Info

Publication number: CN1354548A
Application number: CN 01138302
Authority: CN
Inventors: 叶春松
Original assignee: Wuhan University WHU
Current assignee: Wuhan University WHU
Priority date: 2001-12-17
Filing date: 2001-12-17
Publication date: 2002-06-19
Anticipated expiration: 2021-12-17
Also published as: CN1126233C

Abstract

The invention discloses a non-chemical, online purifying method and purifying system for cooling water in water internal cooling type electrical generator and phase modified installed in thermal power stations, nuclear power station and hydroelectric power station. The characteristics are as follows. A reverse osmosis equipment and gas mass transferring film equipment are installed on circular cooling water system and bypass system, in order to carry on purifying process in complete flow or part of purifying process to internal cooling water. The purifying syst em is composed of the circular cooling water system and bypass purifying system and internal cooling waer box with anti dirt device for high pure water installed on its breathing opening. The invented system provides functions as follows. These are controlling dissolved oxygen and carbon dioxide below certain quantity, removing water-fast particle and soluble salts as well as controlling electric conductivity and dissolved copper in certain region. Thus it guarantees good quality of cooling water and restrains copper conductor with hollow core from corrupt.

Description

Non-chemical on-line purification method and system for cooling water of generator and phase modifier

Technical Field

The invention relates to a non-chemical online purification method and a non-chemical online purification system for cooling water of a generator and a phase modulator, and belongs to the technical field of motor engineering.

Background

High-purity water is generally adopted for cooling in a circulating way in a thermal power plant, a steam turbine generator in a nuclear power plant, a hydraulic power plant hydraulic generator stator winding, a double-water internal-cooling generator rotor winding and a large-scale transformer substation internal-water-cooling phase modifier, the quality of cooling water is polluted by oxygen and carbon dioxide in the air to deteriorate, so that hollow copper conductors are corroded, and the protection method adopted at present is to seal a cooling water tank by using nitrogen or hydrogen and add corrosion inhibitors such as MBT (methyl butyl titanate) or BTA (BTA) and derivatives thereof to internal cooling water (see generator cooling medium, water conservancy and power publishing company, first edition 11 months in 1995). Because the air tightness of the internal cooling water circulation system and the water supply pipeline thereof is difficult to ensure, the method of sealing the gas by using nitrogen or hydrogen is rarely adopted in engineering practice, and the use of the hydrogen has potential safety hazards. The method of adding corrosion inhibitors such as BTA is common, but the main problems are that: 1. detecting the residual concentration of the active carbon in the system by manual addition and manual sampling analysis; 2. the corrosion inhibitor is weak electrolyte, does not have characteristic parameters suitable for online detection, and is not suitable for automatic control; 3. the corrosion inhibitor is an organic matter containing a benzene ring structure, and the formed protective film has high thermal resistance and is not beneficial to cooling and heat dissipation of the copper wire winding of the generator; 4. frequent manual replenishment of the agent is required to repair the protective film. In fact, at present, many power plants do not adopt any regulation and control measures for the internal cooling water of the generator, the pH value of the internal cooling water is low for a long time, the Cu content often exceeds the standard, the conductivity is qualified only by adopting a method of frequently changing water, and the method does not solve the corrosion problem of the copper wire. The quality problem of the inner cooling water becomes one of the potential safety hazards of the generator and the phase modifier, and the output of the generator and the phase modifier is limited.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a non-chemical online purification method and a purification system for cooling water of an internal water-cooled phase modifier of a thermal power plant, a hydroelectric power plant, a nuclear power plant and a large-scale transformer substation. Aiming at the fact that the most main factors influencing the quality of the internal cooling water and the most main factors causing the corrosion of the hollow copper wire are dissolved oxygen and dissolved carbon dioxide, a non-chemical treatment purification method is provided, wherein a Reverse Osmosis (RO) device is adopted to remove particles and dissolved salts possibly existing in cooling water, and a Gas Transmission Membrane (GTM) device is adopted to remove oxygen and carbon dioxide dissolved in the cooling water.

The non-chemical online purification method for the cooling water of the generator and the phase modifier is realized as follows: a purification device consisting of a reverse osmosis device and a gas transmission membrane device (RO + GMT) is arranged in a circulating cooling water system or a bypass purification system, and the internal cooling water is subjected to full-flow purification treatment or partial purification treatment.

The partial purification system for realizing the online purification method of the invention comprises the following steps: the system comprises a circulating cooling water system and a bypass purification system, wherein the circulating cooling water system mainly comprises a generator 1, an internal cold water tank 2, a circulating pump 3, a water replenishing valve 12 and a drain valve 14; the bypass purification system mainly comprises a purification device (RO + GTM)5 consisting of a reverse osmosis device RO and a gas transmission membrane GTM device. The purification device 5 is connected with a control unit (DCU)7 through electromagnetic valves 4 and 6, and a conductivity meter 8, a dissolved oxygen meter 9 and an electromagnetic valve 10.1 are connected between the control unit 7 and an inner cooling water circulation system of the generator 1.

The full-flow purification system for realizing the online purification method of the invention is characterized in that a purification device (RO + GTM)5 is composed of a reverse osmosis device RO and a gas transmission membrane device GTM and is arranged in a circulating cooling water system, a loop is composed of a newly-built generator 1, an inner cooling water tank 2, a circulating pump 3 and the purification device 5, and the full-flow purification system is suitable for the full-flow purification treatment method.

The invention has the advantages that: removing dissolved salts such as CuHCO from the cold water by RO + GTM device₃、Cu(HCO₃)₂The invention can effectively prevent the corrosion of the hollow copper wire of the generator and the phase modifier, and improve the safety and the economical efficiency of the operation of equipment.

Drawings

FIG. 1 is a schematic view of a purification apparatus as an embodiment of a bypass purification process;

fig. 2 is a schematic view of an embodiment in which the purification apparatus is installed in a cooling water circulation system.

Detailed Description

The invention is further illustrated with reference to the following figures and examples:

FIG. 1 is a purge system that can be applied to existing operating systems, as well as to newly built systems. This embodiment is implemented by changing a small mixed bed in an already-established and used internal cooling water bypass purification system into an (RO + GTM) purification device 5, which operates in a bypass partial flow purification treatment mode. Shown in figure 1: in the figure: 1. the generator or phase modifier hollow copper conductor, 2, the internal cold water tank, 3, the cooling water circulating pump. Under the action of the circulating pump 3, water in the inner cooling water tank 2 carries out circulating motion to cool the hollow copper wire of the generator 1 or the phase modifier. The measurement and control unit (DCU)7 collects water quality information from the conductivity meter 8 and the dissolved oxygen meter 9, controls the opening and closing of the electromagnetic valves 4 and 6 according to the detection result, and controls the operation and the stop of the purification device (RO + GTM)5 consisting of the reverse osmosis device RO and the gas mass transfer module device (GTM). And if the detected conductivity is more than 2.0 mu S/cm, opening the water replenishing valve 12 and the drain valve 14 to change the water. The water supplementing quantity and the sewage discharge quantity are balanced and adjusted according to the flow meters 11 and 12; and (4) carrying out regular on-off control on the electromagnetic valve 10 according to a set value, and detecting the quality parameter of the internal cooling water.

Fig. 2 shows another specific example of the full-flow purification system of the present invention, which is a new-built generator and phase modifier cold water main circulation system with a purification device (RO + GTM)5 installed therein, and a full-flow purification treatment method and a bypass are adopted. In fig. 2: 1. the generator or phase modulator hollow copper wire winding, 2, internal cold water tank, 3, internal cold water circulating pump, under the action of which the internal cold water can be circulated through the pipeline system in which the electromagnetic valve 16, the purifying device 5(RO + GTM) and the electromagnetic valve 17 are positioned. The quality of the internal cooling water is detected by a conductivity meter 8 and a dissolved oxygen tester 9, and according to the detection result, a measurement and control unit (DCU)7 determines whether the internal cooling water circulates after being purified by a purification treatment device 5(RO + GTM) or circulates through a bypass pipeline where an electromagnetic valve 15 is located. If the conductivity exceeds 2.0S/cm, the measurement and control unit 7 opens the electromagnetic valves 12 and 14 to carry out water supplementing and sewage discharging operations, and prompts to check whether the purifying device fails; the water make-up and blowdown quantities are adjusted in balance based on the signals provided by the flow meters 11 and 13. The detection instruments of the water quality parameters of the internal cooling water conductivity meter 8, the dissolved oxygen meter 9 and the like adopt a discontinuous sampling detection method, and the opening and the closing of the electromagnetic valve 10 are controlled by the measurement and control unit 7 according to a set value.

The purification method of the invention is shown in figure 1 and figure 2: installing an (RO + GTM) device in a circulating cooling water system or a bypass system, and carrying out full-flow purification treatment or partial purification treatment on the internal cooling water; the method comprises the steps of periodically detecting the conductivity and dissolved oxygen of the inner-cooling water as required by adopting a discontinuous sampling mode, and determining the operation or the shutdown of the purification device according to a detection result; a high-purity water antifouling device is arranged at a breathing port of the inner cold water tank, oxygen and carbon dioxide in air sucked by the water tank under the breathing action caused by water level change are removed, and the stability of the treatment effect of the inner cold water through (RO + GTM) is ensured; when the dissolved oxygen content of cold water in the system is detected to exceed 30ppb, the purification treatment device is started; when the content of the dissolved oxygen is detected to be lower than 5ppb, the operation of the purification device is stopped, and a bypass circulation cooling system is started for the treatment of full flow; for partial flow treatment, the purification unit is shut down; when the detected conductivity of the internal cooling water exceeds 2.0 mu S/cm, the drain valve and the demineralized water replenishing valve are opened simultaneously, and part of water in the internal cooling water tank is replaced. This latter condition does not occur frequently, and if it occurs, it indicates that the purification treatment apparatus is out of service, so that the conductivity is both a supervision index of the operation of the energized equipment for the requirement of the internally cooled water and a supervision index of the failure of the purification apparatus.

The principle of the invention is as follows: based on the following facts, in the cold water with demineralized water as a water source without any adjustment, dissolved oxygen and dissolved carbon dioxide are the root causes of corrosion of the hollow copper wire, and the corrosion reaction is as follows: (1) (2) (3) (4) (5) (6)

reactions 1, 2 and 3 are oxygen corrosion of copper in pure water, with the progress of the reaction producing OH^-Can inhibit the reaction from proceeding, but H generated in the reaction 4⁺OH is neutralized^-Promoting the oxygen corrosion to be continuously carried out; on the other hand, reaction 4 produces H⁺Cu with certain protection function according to reactions 5 and 6₂Dissolving O and CuO film to make the ionic copper, i.e. Cu, come out from the internal cold water⁺、Cu²⁺And is in favor of O₂And diffuse to the base copper, thereby accelerating the corrosion of the base copper.

Claims

1. A non-chemical on-line purification method for cooling water of a generator and a phase modifier is characterized in that a purification device consisting of a reverse osmosis device and a gas transmission membrane device (RO + GMT) is arranged in a circulating cooling water system of an internal cooling water generator or a phase modifier or in a bypass purification system, and the internal cooling water is subjected to full-flow purification treatment or partial purification treatment.

2. The purification method according to claim 1, wherein the full flow purification process and the partial purification process comprise: A. sampling, namely adopting discontinuous sampling; B. and starting the operation of the.

3. The purification method according to claim 2, wherein the electrical conductivity and the dissolved oxygen amount according to which the operation is started or stopped are determined according to the following procedure: A. when the dissolved oxygen content of the internal cooling water exceeds 30ppb, starting the purification treatment device; B. stopping the operation of the purification device when the dissolved oxygen content is less than 5 ppb; for the treatment of full flow, the bypass circulating cooling system is started at the same time, and for the treatment of partial flow, the operation of the purification device is stopped; C. when the conductivity of the inner cold water exceeds 2.0 mu S/cm, the drain valve and the demineralized water replenishing valve are opened simultaneously, and the water in the part of the inner cold water tank is replaced.

4. A partial purification system for realizing the purification method of claim 1, which comprises a circulating cooling water system and a bypass purification system, wherein the circulating cooling water system mainly comprises a generator (1), an inner cooling water tank (2), a circulating pump (3), a water replenishing valve (12) and a drain valve (14); the bypass purification system mainly comprises a purification device (RO + GTM) (5) consisting of a reverse osmosis device RO and a gas transmission membrane device GTM, wherein the purification device (5) is connected with a control unit (DCU) (7) through electromagnetic valves (4) and (6), and a conductivity meter (8), a dissolved oxygen meter (9) and an electromagnetic valve (10.1) are connected between the control unit (7) and an inner cooling water circulation system of the generator (1).

5. A full flow purification system for carrying out the purification method according to claim 1, characterized in that it comprises a reverse osmosis device RO and a gas transmission membrane device GTM to form a purification device (RO + GTM) (5) and is installed in a circulating cooling water system, and a new generator (1), an internal cooling water tank (2), a circulating pump (3) and the purification device (5) form a loop, which is suitable for the full flow purification treatment method.

6. Purification system according to claim 4 or 5, wherein the breathing opening of the inner cold water tank (2) is fitted with a high purity water anti-fouling device for removing oxygen and carbon dioxide from the inhaled air.