JP4745990B2 - Turbine equipment and initial switching method for oxygen treatment of turbine equipment - Google Patents

Description

  The present invention relates to a turbine facility that suppresses elution of iron components in feed water and an initial switching method for oxygen treatment of the turbine facility when the volatile material treatment (AVT) of turbine feed water is first switched to oxygen treatment (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. 4 is known. As shown in FIG. 4, 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. A condenser 106 for supplying water and a water supply system A for supplying the condensed water condensed in the condenser 106 as the feed water 107 to the boiler 118 side. In the water supply system A, a condensate pump 18 and a condensate booster pump 21 are interposed in the water supply pipe 13 between the condenser 106 and the low-pressure water heater 109. Between the feed water heater 112, a deaerator 110, a storage tank 111, and a boiler feed water pump 22 are interposed in the feed water 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. It is set to 5 ppm or more.
In general, since the occurrence of erosion / corrosion (corrosion / erosion) due to the flow is concerned when the pH of the feed water falls below 9.0, the pH of the feed water 107 is set to 9.5 (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 2002-180804 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 about once every two years in order to prevent iron corrosion of the boiler piping during the stop period.
Therefore, in order to obtain a CWT that does not require acid cleaning for more than 10 years, as shown in FIG. 4, the CWT is provided with a first oxygen injection unit 31-1 and a second oxygen injection unit 31-2, and water supply 107. Oxygen is injected therein 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 part 31-1, the second oxygen injection part 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, it is necessary to set the pH to 9.3 or lower, which is the condition for oxygen treatment. Therefore, until oxygen reaches a predetermined amount (for example, 50 μg / L), there is no oxygen in the water supply, and iron It was forced to elute.
Therefore, in order to quickly set the oxygen concentration to a predetermined amount, in oxygen switching, a large amount (200 μg / L) is supplied from the two oxygen injection portions 31-1 and 31-2 while measuring the oxygen concentration with the oxygen concentration meter 32. About oxygen).

  As described above, since the pH concentration is lowered to 9.3 or less, for example, 9.0 at the time of CWT switching, which is a condition of CWT, oxygen is consumed for the oxidation action, and the iron concentration in the feed water is temporarily increased. Therefore, it is necessary to increase the amount of oxygen injected, and the number of oxygen injection locations is two, and the advent of oxygen treatment with a simpler configuration is desired.

  An object of this invention is to provide the turbine equipment which can suppress the raise of the iron concentration in the feed water supplied to a boiler, and the initial switching method of the oxygen treatment of a turbine equipment in view of the said problem.

  A first invention of the present invention for solving the above-described problems includes 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. And an initial switching method of the oxygen treatment of the turbine equipment comprising the feed water system for feeding the condensate condensed in the condenser to the exhaust heat recovery boiler side, the oxygen treatment from the volatile substance treatment (AVT) of the turbine feed water When switching to (CWT) for the first time, oxygen is supplied in a state of pH 9.3 to 9.6, oxygen is set to a predetermined concentration throughout the water supply system, and then the pH is adjusted to 8.5 to 9.3. The difference in pH between before and after is 0.3 or more.

  According to a second aspect of the present invention, in the first aspect of the present invention, there is provided an initial switching method for oxygen treatment of a turbine facility, characterized in that the oxygen supply is injected into the feed water from a single outlet of the condenser.

  According to a third aspect of the present invention, there is provided a boiler that generates steam by heat from a heat source, a steam turbine that is operated by steam of the boiler, a condenser that condenses exhaust gas from the steam turbine, and condensation in the condenser Water supply system for feeding the condensed condensate as feed water to the boiler side, an oxygen injection section for injecting oxygen into the feed water of the water supply system on the outlet side of the condenser, and a deaerator for degassing the feed water A first oxygen concentration meter that measures the oxygen concentration in the feed water on the downstream side, and a second oxygen concentration meter that measures the oxygen concentration in the boiler water on the outlet side of the boiler, and the turbine feed water When first switching from volatile substance treatment (AVT) to oxygen treatment (CWT), oxygen is supplied at a pH of 9.3 to 9.6 to bring the entire water supply system to a predetermined concentration, and then the pH is set to 8 .5 to 9.3 and before and after switching In turbine equipment and a difference H is 0.3 or more.

  According to the present invention, when the water quality control method of the feed water is first switched from AVT to CWT, oxygen is injected into the feed water while maintaining the pH at 9.3 to 9.6, for example, pH 9.5, and then the pH is adjusted. By setting the pH to 8.5 to 9.3, for example, pH 9.0, dissolution of iron is suppressed.

  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. A condenser 106 for condensing the exhaust gas of the boiler, a water supply system A for supplying the condensate condensed in the condenser 106 to the boiler 118 side as water supply 107, and water supply at the outlet side of the condenser 106 The chemical injection part 30 for adjusting the pH in the water supply 107 of the system A, the oxygen injection part 31 for injecting oxygen into the water supply 107 of the water supply system A on the outlet side of the condenser 106, and the water supply 107 are deaerated. A first oxygen concentration meter 32-1 that measures the oxygen concentration in the feed water 107 on the downstream side of the deaerator 110, and a second oxygen concentration that measures the oxygen concentration in the boiler water on the outlet side of the boiler 118. Total 32-2 It is intended to include a.
And when switching from the volatile substance treatment (AVT) which is the water quality treatment of the turbine feed water to the oxygen treatment (CWT) for the first time, oxygen is supplied in a state of pH 9.3 to 9.6 (for example, pH 9.5), The oxygen is set to a predetermined concentration in the entire water supply system, and then the pH is set to 8.5 to 9.3 (for example, pH 9.0), and the difference in pH before and after switching is set to 0.3 or more.

  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 is confirmed by providing a 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. 2 is measured by the oxygen concentration meter 32-2, and after confirming that the oxygen in the second oxygen concentration meter 32-2 has reached a predetermined concentration, a pH adjusting agent (for example, supplied by the drug injecting unit 30) (Ammonia) injection amount is changed so that the pH condition of CWT is obtained.

  As a result, in the conventional CWT, when the AVT is switched to the CWT, an increase in iron solubility caused by changing the pH from, for example, 9.5 to 9.0 can be suppressed.

That is, in the present invention, after confirming that the second oxygen concentration meter 32-2 installed at the outlet of the boiler 118 has reached a predetermined concentration (for example, 50 μg / L), the pH is adjusted to 8.5-9. .3, for example, by reducing the pH to 9.0, it is possible to suppress iron dissolution in the feed water 107, so that the iron concentration in the feed water can be suppressed.
In the present embodiment, the second oxygen concentration meter 32-2 is provided on the inlet side of the superheater 114. However, the present invention is not limited to this, and the second oxygen concentration meter 32-2 is provided on the outlet side of the superheater 114. You may make it provide.

  As a result, conventionally, as shown in FIG. 4, in the water supply system A, oxygen is injected from two locations of the first oxygen injection portion 31-1 and the second oxygen injection portion 31-2. By doing so, the equipment can be reduced.

  In addition, since the pH is lowered after oxygen reaches the water supply system sufficiently, dissolution of iron in the water supply can be prevented.

<Test example>
Next, the test results are shown for the change in pH when 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 feed water. 2 and FIG.

  In the embodiment according to the present invention, switching from AVT to CWT was performed after confirming that the concentration reached a predetermined concentration (50 μg / L). As a result, the iron concentration in the feed water 107 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 feed water 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, it became possible to suppress dissolution of iron in the water supply.

  As described above, in the present invention, when switching from AVT to CWT, the pH is changed in the AVT state at the initial stage of switching, and after confirming that the oxygen concentration at the boiler outlet becomes a predetermined concentration, the pH is changed to CWT. By setting it as these conditions, melt | dissolution of the iron to water supply can be suppressed.

It is the schematic of the turbine installation which concerns on the Example of this invention. 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

DESCRIPTION OF SYMBOLS 10 Turbine equipment 11 Steam 118 Boiler 106 Condenser 107 Water supply A Water supply system 30 Chemical injection part 31 Oxygen injection part 32-1 1st oxygen concentration meter 32-2 2nd oxygen concentration meter

Claims (3)

A boiler that generates steam by heat from the heat source, a steam turbine that operates with the steam of the boiler, a condenser that condenses the exhaust of the steam turbine, and the condensate condensed in the condenser is on the exhaust heat recovery boiler side In the initial switching method of oxygen treatment of turbine equipment consisting of a water supply system that feeds
When first switching from volatile treatment (AVT) to oxygen treatment (CWT) for turbine feedwater,
Oxygen is supplied in a state of pH 9.3 to 9.6, oxygen is set to a predetermined concentration throughout the water supply system, pH is then adjusted to 8.5 to 9.3, and the difference in pH before and after switching is 0.3. An initial switching method for oxygen treatment of turbine equipment, which is as described above. In claim 1,
An initial oxygen switching method for turbine equipment, characterized in that oxygen supply is injected into feed water from a single outlet of a condenser.   A boiler that generates steam by heat from a heat source, a steam turbine that is operated by the steam of the boiler, a condenser that condenses exhaust gas from the steam turbine, and water that is condensed by the condenser As a water supply system for feeding to the boiler side, an oxygen injection part for injecting oxygen into the water supply of the water supply system at the outlet side of the condenser, and a water supply on the downstream side of the deaerator for degassing the water supply A first oxygen concentration meter that measures the oxygen concentration in the boiler, and a second oxygen concentration meter that measures the oxygen concentration in the boiler water on the outlet side of the boiler. When switching from AVT) to oxygen treatment (CWT) for the first time, oxygen is supplied in a state of pH 9.3 to 9.6, and oxygen is brought to a predetermined concentration throughout the water supply system, and then the pH is adjusted to 8.5 to 9.3. And the difference in pH before and after switching is 0. Turbine equipment characterized in that at least.

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