JP2009243836A - Oxygen processing method of turbine equipment, and turbine equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen processing method of turbine equipment efficiently supplying oxygen into condensate in CWT, and to provide the turbine equipment. <P>SOLUTION: The turbine equipment includes: a boiler 118 for generating steam 11 by heat from a heat source; a steam turbine 12 operated by the steam 11 of the boiler 118; a steam condenser 106 for condensing exhaust from the steam turbine 12; a water feed system A for feeding the condensed water condensed by the steam condenser 106 as condensate 107-1 to the boiler 118 side; a drug filling part 30 for adjusting the pH in the condensate 107-1 of the water feed system A at an outlet of the steam condenser 106; a first oxygen content meter 32-1 for measuring the oxygen content in the condensate 107-1 at the slip stream side of a deaerator 110 for deaerating the condensate 107-1; and a second oxygen content meter 32-2 for measuring the oxygen content in boiler water at an outlet of the boiler 118, wherein oxygen is caused to leak in the condensate 107-1 by adjusting a vacuum breaker 20 of the steam condenser 106. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a turbine equipment oxygen treatment method and turbine equipment capable of efficiently supplying oxygen into condensate in a CWT.

  Conventionally, in thermal power and nuclear power plants, generated high-temperature and high-pressure steam is supplied to a turbine, and the turbine is driven by this steam to generate power. The steam after driving the turbine is cooled by the condenser and returned to the water state, then heated again, supplied to the boiler, the nuclear reactor, and the steam generator, and reused.

  As an example of turbine equipment in a thermal power plant, one having a configuration as shown in FIG. 7 is known. As shown in FIG. 7, the turbine equipment 100 includes a boiler 118 that generates steam 11 by heat from a heat source, a steam turbine 12 that is operated by the steam 11 of the boiler 118, and exhaust gas from the steam turbine 12. The condenser 106 to be watered and the condensed water condensed in the condenser 106 are used as the condensate 107-1, and are supplied to the boiler 118 side through the deaerator 110 as the feed water 107-2. It is comprised from the water supply system A. In the water supply system A, a condensate pump 18 is interposed in the water supply pipe 13 between the condenser 106 and the low pressure water heater 109, and between the low pressure water heater 109 and the high pressure water heater 112. The deaerator 110, the storage tank 111, and the boiler feed pump 19 are interposed in the feed pipe 13. Reference numeral 104 is a makeup water tank, 105 is makeup water, 114 is a superheater, and 115 is a reheater.

Further, on the outlet side of the condenser 106 of the water supply pipe 13 of the water supply system A, a chemical injection unit 30 for injecting ammonia as a pH adjusting agent and hydrazine as a deoxidizing agent is provided, and a volatile substance treatment ( All Volatile Treatment (AVT). In this AVT, a predetermined amount of hydrazine is injected and a predetermined amount of ammonia is injected into the feed water for pH adjustment from the drug injecting unit 30. The pH of the feed water is set to 9.5 or higher and the ammonia concentration is set to be 0.00. It is set to 5 ppm or more.
In general, when the pH of the condensate falls below 9.0, there is a concern about the occurrence of erosion / corrosion (corrosion / erosion) due to the flow, so the pH of the condensate 107-1 is set to 9.4 to 9.7. (Patent Document 1).
In this AVT, magnetite (Fe ₃ O ₄ ) is formed on the surface of a base material in order to suppress iron corrosion on a water supply pipe or the like.

JP 2003-254503 A

By the way, in the turbine equipment 100 that performs such AVT, when the plant is stopped during periodic inspection or the like, a combined water treatment (CWT) is performed in which a small amount of oxygen is dissolved from the AVT into the water supply. .
This is because in AVT, it is necessary to perform acid cleaning once every two years during the plant shutdown period in order to prevent iron corrosion of boiler piping.
Therefore, in order to obtain a CWT that does not require acid cleaning for more than 10 years, as shown in FIG. 7, the CWT is provided with a first oxygen injection unit 31-1 and a second oxygen injection unit 31-2 to supply water 107. -2 is injected with oxygen to dissolve a predetermined amount of oxygen.

Here, the two oxygen injection portions are provided because it takes time for oxygen to reach the inside of the water supply system A. Specifically, the first oxygen is provided on the outlet side of the condenser 106. In addition to the injection unit 31-1, a second oxygen injection unit 31-2 is installed on the downstream side of the deaerator 110.
In this oxygen treatment, the water component is controlled from the divalent state (magnetite coating) to the trivalent state (hematite coating) having lower iron solubility by the action of oxygen.

When switching to this CWT, in order to quickly set the oxygen concentration to a predetermined amount, in the oxygen switching, a large amount of oxygen is injected from the two oxygen injection units 31-1 and 31-2 while measuring the oxygen concentration with the oxygen concentration meter 32. Since oxygen (about 200 μg / L) is injected, there is a problem of excessive capital investment in a plant with low operation frequency.
That is, the oxygen injection facilities 31-1 and 31-2 require a large amount of oxygen cylinders or PSA oxygen generators and a control device for controlling them, so that the installation cost increases.

  In addition, when the plant operation time is short, it takes time to switch the CWT to obtain a predetermined concentration of oxygen (for example, 2 weeks to 6 months), and it is difficult to control the upper limit of oxygen (about 200 μg / L). There is a problem that it is necessary to prevent injection.

  In view of the above problems, an object of the present invention is to provide a turbine equipment oxygen treatment method and turbine equipment capable of efficiently supplying oxygen into condensate in a CWT.

  A first invention of the present invention for solving the above-mentioned problems is a boiler that generates steam by heat from a heat source, a steam turbine that operates by steam of the boiler, and a condenser that condenses the exhaust of the steam turbine. In an oxygen treatment method for turbine equipment comprising a water supply and a water supply system that supplies the condensate condensed in the condenser to the boiler side as condensate, the condensate vacuum means of the condenser is adjusted by adjusting the condensate vacuum means. The present invention resides in an oxygen treatment method for turbine equipment, wherein dissolved oxygen is supplied into water.

  A second invention is the oxygen treatment method for turbine equipment according to the first invention, wherein the concentration of dissolved oxygen supplied to the condensate is 5 to 20 μg / L.

  According to a third aspect, in the first or second aspect, when the turbine feed water is switched from the volatile substance treatment (AVT) to the oxygen treatment (CWT), oxygen is supplied in a state of pH 9.4 to 9.7 of the AVT condition. Then, the oxygen treatment method for turbine equipment is characterized in that oxygen is set to a predetermined concentration in the entire water supply system, and then the pH is set to 8.0 to 9.3 of the CWT condition.

According to a fourth aspect of the present invention, there is provided a boiler that generates steam by heat from a heat source, a steam turbine that operates by the steam of the boiler, a condenser that condenses the exhaust of the steam turbine, and the condenser that is condensed. in condensing turbine facility comprising a water supply system for feeding the boiler side, the condensate circulation line for extracting part of condensate from the condenser is interposed the condensate circulation line, removing CO ₂ The turbine equipment includes a condensate tank to which the air is supplied.

  According to the present invention, when the water quality control method for water supply is switched from AVT to CWT, dissolved oxygen is supplied into the condensate by adjusting the condensate vacuum means of the condenser, and no separate oxygen injection facility for the condensate is required. By doing so, the CWT operation is simplified.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A turbine facility according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram of a turbine facility according to an embodiment. In the figure, the same components as those shown in FIG.

As shown in FIG. 1, a turbine facility 10 according to the present embodiment includes a boiler 118 that generates steam 11 by heat from a heat source, a steam turbine 12 that operates with the steam 11 of the boiler 118, and the steam turbine 12. The condenser 106 for condensing the exhaust gas of the boiler, the water supply system A for supplying the condensate 107-1 condensed in the condenser 106 to the boiler 118 side, and the water supply at the outlet side of the condenser 106 The oxygen concentration in the feed water 107-2 is measured on the downstream side of the chemical injection unit 30 that adjusts the pH in the condensate 107-1 of the system A and the deaerator 110 that degass the condensate 107-1. A first oxygen concentration meter 32-1 and a second oxygen concentration meter 32-2 that measures the oxygen concentration in the boiler water on the outlet side of the boiler 118, and the vacuum break adjustment of the condenser 106 are provided. The condensate is adjusted by adjusting the valve 20. Supplying dissolved oxygen to the condensate water with oxygen that is leaking (dissolved) in 07-1.
Moreover, you may make it provide the 3rd oxygen concentration meter 32-3 which measures the oxygen concentration in boiler water in the exit side of the superheater 114.

FIG. 2 is a schematic view of the configuration of a condenser having a condenser vacuum pump and a vacuum breaker valve.
As shown in FIG. 2, the condenser 106 includes a vacuum break adjustment valve 20 and a condenser vacuum pump 21, and removes carbon dioxide (CO ₂ ) in the air leaked by the vacuum break adjustment valve 20. A CO ₂ removal unit 22 is provided. This is because carbon dioxide gas (CO ₂ ) becomes an anion in the condensate 107-1, and the electrical conductivity in the condensate 107-1 increases, and this is prevented.

Here, the dissolved oxygen concentration of CWT is 20 to 200 μg / L according to JIS standards, but as shown in FIG. 4, if it is at least 5 μg / L or more (more preferably 5 to 20 μg / L), hematite for CWT operation is used. Since a film can be formed, oxygen can be supplied to the condensate 107-1 with a smaller amount of air leakage, which is preferable.
As a result, a conventional oxygen injection facility is not required, and a large capital investment is not required.

Further, as shown in FIG. 3 showing another embodiment, a condensate circulation line 24 is provided, which is provided with a condensate tank 23 that circulates a part of the condensate 107-1. Air may be dissolved in the stored water. Here, air is introduced into said condensate water tank 23, followed by removal of CO ₂ by CO ₂ removal unit 22. In FIG. 3, reference numeral 26 denotes a vacuum break valve (normally closed).
Here, if 5 t / h of condensate is supplied (10 mg / L → 10,000 μg / L) and circulated with respect to 2500 t / h of condensate, the oxygen concentration increases by 2 μg / L.

  Thereby, the oxygen concentration of the condensate 107-1 can be raised by passing the condensate circulation line 24 through the condensate tank 23 sealed with the air cylinder.

  That is, when the pressure is increased to 0.1 MPa, the dissolved oxygen concentration becomes +4 μg / L (twice the atmospheric pressure). Further, when the pressure is increased to 0.15 MPa, the dissolved oxygen concentration becomes +5 μg / L (2.5 times the atmospheric pressure). The condensate circulation line 24 is provided with a pressure regulating valve 25 so as to be adjusted to a desired pressure.

  Therefore, the vacuum break adjustment valve 26 is used for the vacuum adjustment of the condenser 106, which is the original application, and separately circulates a part of the condensate 107-1 in the condensate circulation line 24, thereby increasing the amount of dissolved oxygen. And CWT conditions.

  Furthermore, when switching from volatile substance treatment (AVT), which is a water quality treatment of turbine feed water, to oxygen treatment (CWT) for the first time, oxygen is supplied in a state of pH 9.4 to 9.7 (for example, pH 9.5), The oxygen is set to a predetermined concentration throughout the water supply system, and then the pH is set to 8.0 to 9.3 (for example, pH 9.0).

  Here, when switching from AVT to CWT for the first time in the present invention, the turbine equipment that is performing AVT as the water quality management condition is when the plant is shut down at the first periodic inspection or the test operation is performed under the AVT water quality management condition. It means that when switching to CWT for the first time after the trial run is completed.

  The oxygen concentration in the feed water 107-2 is confirmed by providing the first oxygen concentration meter 32-1 on the outlet side of the deaerator 110 and the oxygen concentration in the boiler water between the boiler 118 and the superheater 114. Is measured by the second oxygen concentration meter 32-2, and after confirming that the oxygen in the second oxygen concentration meter 32-2 has reached a predetermined concentration, the pH adjusting agent supplied by the drug injecting unit 30 By changing the injection amount of (for example, ammonia), the pH condition of CWT is set. Or you may make it adjust pH by measuring the oxygen concentration in the feed water 107-2 with the 3rd oxygen concentration meter 32-3 provided in the exit side of the superheater 114. FIG.

  As a result, when switching from AVT to CWT in a turbine facility, the pH is changed from a state of 9.4 to 9.7 (for example, 9.5) to 8.0 to 9.3 (for example, 9.0). Can suppress an increase in iron solubility.

  That is, in the present invention, in either the second oxygen concentration meter 32-2 or the third oxygen concentration meter 32-3 installed at the outlet of the boiler 118, the oxygen in the feed water 107-2 has a predetermined concentration (for example, 20 μg). / L), the iron dissolution in the condensate 107-1 is suppressed by lowering the pH to 8.0 to 9.3 (for example, pH 9.0). Therefore, it is possible to suppress an increase in the iron concentration in the condensate.

  As a result, conventionally, as shown in FIG. 7, in the water supply system A, the injection of oxygen from the two locations of the first oxygen injection section 31-1 and the second oxygen injection section 31-2 is abolished. Thus, the plant facilities can be reduced and the pH is lowered after oxygen has sufficiently spread within the water supply system, so that the dissolution of iron into the water supply can be prevented.

<Test example>
Next, the test results on the change in pH at the time of switching from AVT to CWT in the present invention and the prior art, the change in oxygen concentration in the first and second oximeters, and the change in iron concentration in the water supply are shown. It shows in FIG.5 and FIG.6.

  In the embodiment of the present invention, switching from AVT to CWT was performed after confirming that the oxygen concentration in the condensate reached a predetermined concentration (50 μg / L). As a result, the iron concentration in the condensate 107-1 hardly changed.

  On the other hand, in the comparative example which is the prior art, the pH is set to 9.0 simultaneously with the oxygen injection when switching from AVT to CWT, and the oxygen concentration in the condensate is quickly set to a predetermined concentration (50 μg / L). In addition, since 200 μg / L of oxygen was initially supplied, the oxygen concentration increased and the amount of dissolved iron temporarily increased significantly.

  From the above results, in the case of switching from AVT to CWT, in the initial stage of switching, the pH was changed to the AVT state, and after confirming that the oxygen concentration at the boiler 118 outlet became a predetermined concentration, the pH was changed to the CWT condition. By doing so, the dissolution of iron in the condensate can be suppressed.

  As described above, the oxygen treatment method for turbine equipment and the turbine equipment according to the present invention supply dissolved oxygen in the condensate by adjusting the condensate vacuum means of the condenser, and no separate oxygen injection equipment for the condensate is required. By doing so, simplification of CWT operation can be achieved.

It is the schematic of the turbine installation which concerns on the Example of this invention. It is the schematic of the condenser which concerns on a present Example. It is the schematic of the other condenser which concerns on a present Example. It is a related figure of dissolved oxygen and a corrosion potential. FIG. 4 is a relationship diagram of pH, oxygen concentration, iron concentration and time according to an example. It is a related figure of pH, oxygen concentration and iron concentration, and time concerning a comparative example. It is explanatory drawing which shows the structure of the turbine installation in the conventional power plant.

Explanation of symbols

10 turbine equipment 11 vapor 118 boiler 106 condenser 107-1 condensate 107-2 Water A Water System 20 vacuum breaker 21 condenser vacuum pump 22 CO ₂ removal unit 23 condensate tank 24 the condensate circulation line 25 pressure regulating valve 30 medicine injection part 32-1 1st oxygen concentration meter 32-2 2nd oxygen concentration meter 32-3 3rd oxygen concentration meter

Claims (4)

A boiler that generates steam by heat from a heat source;
A steam turbine operated by steam of the boiler;
A condenser for condensing the exhaust of the steam turbine;
In the oxygen treatment method of a turbine facility comprising a water supply system for supplying the condensate condensed in the condenser as feed water to the boiler side,
An oxygen treatment method for turbine equipment, wherein dissolved oxygen is supplied into the condensate by adjusting a condensate vacuum means of the condenser. In claim 1,
The oxygen treatment method for turbine equipment, wherein the concentration of dissolved oxygen supplied into the condensate is 5 to 20 µg / L. In claim 1 or 2,
When switching turbine feed water from volatile material treatment (AVT) to oxygen treatment (CWT),
A turbine characterized in that oxygen is supplied in a state of pH 9.4 to 9.7 under the AVT condition, oxygen is brought to a predetermined concentration throughout the water supply system, and then the pH is adjusted to 8.0 to 9.3 under the CWT condition. Equipment oxygen treatment method. A boiler that generates steam by heat from a heat source;
A steam turbine operated by steam of the boiler;
A condenser for condensing the exhaust of the steam turbine;
In the turbine equipment consisting of a water supply system that feeds the condensate condensed in the condenser to the boiler side,
A condensate circulation line for partially extracting condensate from the condenser;
A turbine facility comprising: a condensate tank provided in the condensate circulation line and configured to supply air from which CO ₂ has been removed.

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