JPH11304992A - Turbine equipment for power generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce iron concentration in supply water at low management cost without using chemicals, and maintain and improve the material integrity of a turbine equipment. SOLUTION: This turbine equipment introduces steam generated from a steam generator 1 or a boiler through a main steam pipe 2 to a turbine system of a high pressure turbine 3 and a low pressure turbine 6, generates power by rotating the turbine of this turbine system and driving the generator, condenses the steam having finished work in the turbine system in a main condenser 7 in a condensing system, purifies this condensate with hollow membrane filter 9 in a condensing purification system, heats the water with a low pressure and a high pressure supply water heater 10 and 12 as supply water, and returns this supply water to the steam generator or a boiler. In this case, the supply water flowing in the supply water system is controlled to neutral pure water and at 7 ppb or more of remaining oxygen concentration, and a corrosion resistive material is assembled in a part of components and piping from the steam generator 1 or boiler to the supply water system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine plant for power generation configured to maintain and improve material integrity in a nuclear power plant or a thermal power plant.

[0002]

2. Description of the Related Art In a nuclear power plant or a thermal power plant attached to a steam generator, the amount of iron deposited on the secondary side of the heat transfer tube in order to maintain material integrity of the secondary side of the heat transfer tube in the steam generator. Is reduced as much as possible. In recent years, in order to suppress the deterioration in function due to corrosion of turbine equipment and piping,
Volatile treatment (AV below)
T) to prevent turbine system corrosion.

In AVT, the pH is usually maintained at about 8.7 to 9.5 by adding ammonia, the hydrazine is added to the water supply at 0.2 to 0.6 ppm, and the concentration of oxygen in the water is controlled to almost zero by installing a deaerator. Operating in a deoxidizing or reducing atmosphere.

[0004] However, by lowering the dissolved oxygen, corrosion of the entire material surface is suppressed, but erosion and corrosion accelerated by running water are generated, and there is a possibility that the soundness of equipment and piping is impaired. .

[0005] Further, in a part of a nuclear power plant with a steam generator, a high AV having a further increased pH is used from the viewpoint of corrosion control.
T may be adopted in some cases. In this case, if the condensate demineralizer is used during normal operation, the chemical used for controlling corrosion is captured, and the frequency of regeneration is not enough for operation management, so that it is not used. For this reason, the corrosive substances generated upstream of the condensate system flow out downstream.

[0006] According to the following document, the iron concentration of feed water is 2.3p
It is described to be about pb [HGHEITMANN et
al; Initiial experience gained with a high pH value
inthe secondary system of PWRs, BNES LONDON Water
Chemistry Nuclear systems, 1983].

On the other hand, in thermal power plants, CWT 10 years ago
(Combined Water Treatment) type corrosion control technology is being developed. This is done by injecting chemicals into the entire surface,
By injecting oxygen, erosion and corrosion are suppressed.

[0008]

In a nuclear power plant with a steam generator, even if AVT is adopted, the iron concentration of the feedwater is several pp.
b, the amount of iron oxide deposited on the steam generator has increased over time at the steam generator-attached nuclear power plant,
There is a problem that intergranular corrosion damage (IGA) occurs on the secondary side of the steam generator heat transfer tube due to concentration of impurities there.

[0009] On the other hand, in a thermal power plant, in the AVT, a phenomenon occurs in which iron oxide is deposited in the boiler and the heat exchange rate of the boiler is reduced, and at the same time, erosion and corrosion are performed at a location where the dissolved oxygen concentration is too low. There is a problem that the pipe is worn out.

Even if a high AVT is used in a recent steam generator-attached nuclear power plant or a CWT method is used in a thermal power plant, the amount of chemicals used is enormous, and the cost of chemical management is high. Concerns about pollution are also high. Further, there is a problem that the frequency of chemical regeneration of the resin in the condensate desalination apparatus is high, the amount of the regenerated chemical generated is large, and the management thereof is costly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to reduce the concentration of iron supply water at a low management cost without using chemicals, and to maintain and improve the soundness of materials. It is intended to provide a turbine device for use.

[0012]

According to a first aspect of the present invention, steam generated from a steam generator or a boiler is guided to a turbine system through a main steam pipe, and a turbine of the turbine system is rotated to drive a generator. The steam that has completed its work in the turbine system is condensed and condensed in a condenser in the condenser system, and the condensate is purified in the condensate purification system and heated in the feedwater heater in the water supply system. In the power generation turbine facility for returning the feedwater to the steam generator or the boiler, the feedwater is adjusted to a concentration of 7 ppb or more with neutral pure water, and from the steam generator or the boiler to the feedwater system. It is characterized by incorporating a corrosion-resistant material into a part of the equipment and piping.

[0013] The invention corresponding to claim 2 is characterized in that the iron concentration in the water supply system is 1 ppb or less. The invention corresponding to claim 3 is characterized in that an oxygen gas supply pipe is connected to an upstream pipe of the main steam pipe and a low-pressure feedwater heater of the feedwater system.

[0014] The invention corresponding to claim 4 is characterized in that the corrosion-resistant material is made of weathering steel, low alloy steel or stainless steel. According to a fifth aspect of the present invention, the condensate purification system has at least one of a condensate filter and a condensate desalination device, and the condensate filter is a hollow fiber membrane filter, a non-precoated filter, or a powder ion exchange filter. It is characterized by being made of any one of the resin filters.

According to a sixth aspect of the present invention, a low-pressure heater drain pipe, a low-pressure heater drain pump, and a hollow fiber membrane are formed by connecting a discharge pipe of the condensate condensate pump and a low-pressure heater drain of the low-pressure feedwater heater of the water supply system. It is connected by a filter upstream return pipe, and the upstream return pipe and downstream return pipe of the condensate demineralizer are connected to the hollow fiber membrane filter upstream return pipe and the downstream pipe of the low-pressure feed water heater. .

A seventh aspect of the present invention is characterized in that a noble metal injection device is connected to the steam generator or the boiler. The invention corresponding to claim 8 connects a hydrogen gas supply device to a downstream water supply pipe of the condensate desalination device,
The corrosion potential on the secondary side of the steam generator or boiler is -20
It is characterized by being maintained at an amount of 0 mV or less.

According to the present invention, in order to maintain and improve the material integrity of turbine equipment, without using chemicals,
The purpose of the present invention is to reduce the concentration of iron supplied under neutral pure water conditions.
FIG. 3 shows that the presence of dissolved oxygen suppresses the corrosion of carbon steel. It is known that the corrosion inhibition is due to the formation of a stable oxide film of Fe ₂ O ₃ when dissolved oxygen is present.

FIG. 3 shows Gordon et al., “Hydrogen wat
er chemistry for BWRs "EPRI NP-3935M (1985), cited from the literature, 200-300 ° C (392-572F °)
The corrosion rate and elution rate of carbon steel exposed to different oxygen concentrations for 1000 hours in the temperature range above are shown in relation to the dissolved oxygen concentration.

According to FIG. 4, when the dissolved oxygen is 7 ppb or more, the corrosion promoted by the flow velocity, so-called erosion,
Corrosion (FAC: Flow-Accelerated Corrosion)
Has been shown to be suppressed.

FIG. 4 shows the effect of dissolved oxygen on the corrosive wear accelerated by the flow velocity. The vertical axis indicates the increase in the corrosion wear rate accelerated by the flow velocity, and the horizontal axis indicates the dissolved oxygen (ppb). I have.

5 to 7 show "Thermal and Nuclear Power Generation: Corrosion of Power Plant and Its Prevention, Corrosion Forms and Countermeasures 2" vol.47
No. 6 p677-Jun. 1996, it is clear that low carbon steel has extremely high erosion and corrosion resistance compared to carbon steel.

FIG. 5 shows carbon steel, Ni—Cr—C
FIG. 6 shows the effect of steam wetness on the erosion and corrosion reduction of the u-steel and the Cr-Mo steel, and FIG. 6 shows the effect of the steam wetness similarly. This shows the effect of humidity.

In the present invention, when the heater drain system is a cascade system, the concentration of dissolved oxygen in steam and water is increased by injecting oxygen gas or air into the steam system, and dense oxidation is performed on the equipment and the pipe inner surface. By forming a film, corrosion of the inner surface of equipment and piping is suppressed. Also, in the condensate purification system, iron brought in from the upstream is almost completely removed, and oxygen gas is injected to suppress the generation of iron from the water supply system and reduce the amount of iron brought in from the water supply system to 1 ppb or less. be able to.

On the other hand, when a forward drain system is used, oxygen gas or air is injected into the steam system to increase the concentration of dissolved oxygen in the steam and water to form a dense oxide film on the inner surfaces of equipment and piping. In addition to further suppressing corrosion of equipment and the inner surface of piping by using anticorrosive materials, the concentration of supplied iron is reduced to 1 ppb by installing a condensate purification system and suppressing the generation of iron from the water supply system by injecting oxygen gas. The following is assumed. When the iron concentration of LPPD is high, LPPD can be collected at the upstream of the condensate purification system to remove iron almost completely, so that the iron concentration of feedwater can be reduced to 1 ppb or less.

Further, in the steam generator-attached nuclear power plant, the corrosion potential on the secondary side of the heat transfer tube of the steam generator is reduced to -200 mV or less by injection of feed water hydrogen gas, thereby suppressing the generation of IGA. In order to reduce the injection amount of hydrogen gas in the feed water, the noble metal is plated or coated on the secondary side surface of the steam generator heat transfer tube, or a noble metal solution is injected under high temperature conditions to obtain IG.
Generation of A can be suppressed.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a steam generator-attached power generation turbine facility according to the present invention will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a steam generator, for example, a boiling water reactor. The steam generator 1 incorporates, for example, a core as a heat transfer tube 27, and the main steam tube 2 is connected to the steam generator 1. The main steam pipe 2 is connected to a high-pressure turbine 3 of a turbine system, and a moisture separator 4, a reheater 5, and a low-pressure turbine 6 are sequentially connected downstream of the high-pressure turbine 3.

The low-pressure turbine 6 is provided with a main condenser 7 of a condensing system, a condensing pump 8 is connected downstream of the main condenser 7, and a discharge side of the condensing pump 8 serves as a filtering device. It is connected to a condensate hollow fiber membrane filter (hereinafter, referred to as HFF) 9. A low-pressure feedwater heater 10, a feedwater pump 11, and a high-pressure feedwater heater 12 are sequentially connected to the downstream feedwater system of the HFF 9, and the downstream side of the high-pressure feedwater heater 12 is connected to the steam generator 1 by a feedwater pipe 13. .

The secondary inlet of the high-pressure feed water heater 12 is connected with a bleed pipe 14 connected to the high-pressure turbine 3, a moisture separator drain pipe 15, and a reheater drain pipe 16 connected to the reheater 5. A water supply pump is provided at the secondary outlet of the high pressure feed water heater 12.
A high-pressure heater drain pipe 17 connected to the suction side of 11 is connected via a high-pressure heater drain pump 18.

The low pressure turbine 6 and the secondary side inlet of the low pressure feed water heater 10 are connected by a bleed pipe 19. A low-pressure heater drain bypass pipe (hereinafter, referred to as LPPD) 20 connects the secondary-side outlet of the low-pressure feed water heater 10 to the discharge-side pipe of the HFF 9 via a low-pressure heater drain pump 21.

In FIG. 1, reference numeral 22 denotes an oxygen gas or air supply device 22. This supply device 22 is connected to the upstream side of the main steam pipe 2 via a main steam pressurizing pump 23 and connected to a pipe. , A low pressure feed water heater 10 through a feed water pressurizing pump 24
The piping is also connected to the inlet side water supply system piping. Also, the sign
Reference numeral 25 denotes a hydrogen gas supply device. The hydrogen gas supply device 25 is connected to a downstream water supply pipe of the HFF 9 via a hydrogen gas pressurizing pump 26.

Reference numeral 28 denotes an erosion potentiometer which is connected to the steam generator 1 and the liquid in the steam generator 1 is pumped by the erosion potentiometer.
It flows into 28 and is measured. Reference numeral 29 denotes a noble metal injection device, which is connected to a lower portion of the steam generator 1 via a pump. Reference numeral 30 denotes an exhaust gas system, which is connected to the main condenser 7 via a pump, and the exhaust gas system 30 is provided with an exhaust gas recombiner 31;
The downstream side is connected to an exhaust stack (stack).

Here, the steam generated by the steam generator 1 is passed through the main steam pipe 2 to the high-pressure turbine 3, and then the moisture is separated by the moisture separator 4. Thereafter, it is reheated by the reheater 5, flows into the low-pressure turbine 6, rotates the low-pressure turbine 6, and drives a generator (not shown). The steam after the work is condensed by the main condenser 7 having a built-in cooling pipe made of titanium, for example, to be condensed.

The condensate is sent from the main condenser 7 to the HFF 9 having a condensed water purification capacity of 100% by the condensate pump 8, and the condensate condensate is almost removed. Condensate purified by HFF9 is
The feed water is heated by the low-pressure feed water heater 10 and the high-pressure feed water heater 12 and supplied to the steam generator 1 by the feed water pump 11 through the feed pipe 13. Thus, the steam generator 1
The steam generated in the tank repeats the cycle of the turbine system, condensate system, and water supply system.

During this cycle, the bleed air of the high-pressure turbine 3 used as a heat source of the high-pressure feed water heater 12 flows into the high-pressure feed water heater 12 through the bleed pipe 14. In addition, the moisture separator 4
Drain flows into the high-pressure feed water heater 12 through the drain pipe 15. Further, the drain of the reheater 5 flows into the high-pressure feed water heater 12 through the drain pipe 16. The drain 17 condensed by exchanging heat with the water supply pipe in the high pressure feed water heater 12 is collected upstream of the water supply pump 11 by the high pressure heater drain pump 18 in order to improve heat recovery.

On the other hand, the bleed air of the low-pressure turbine 6 serving as a heat source of the low-pressure feed water heater 10 passes through the bleed pipe 19 to be supplied to the low-pressure feed water heater 10.
After being supplied to the drain, the heat-exchanged drain 20 is recovered downstream of the HFF 9 by the low-pressure heater drain pump 21 through the LPPD 20 in order to improve heat recovery.

Corrosion inhibition downstream of HFF9 and HF
In order to suppress corrosion of turbine equipment flowing downstream of F9, oxygen gas or air supplied from the oxygen gas or air supply device 22 is supplied to the main steam pipe 2 immediately after flowing out of the steam generator 1 by the pressurizing pump 23. Main steam, bleed air and heater drain are supplied so that the dissolved oxygen concentration becomes appropriate.

On the other hand, an oxygen gas supply device is provided downstream of the HFF 9.
Oxygen gas or air supplied from 22 is supplied by a pressurizing pump 24 so that condensed water and supplied water have an appropriate dissolved oxygen concentration. Furthermore, in order to reduce the absolute amount of corrosion, steam and drain equipment and piping flowing downstream of the HFF 9 except for the condensing pipe and the water supply pipe are formed of low alloy steel, and the reheater 5 and the feed water heater are formed. The heat transfer tubes 10 and 12 are made of stainless steel.

As a result, all the turbine systems that flow into the downstream side of the HFF 9 and serve as water supply form a dense oxide film and suppress corrosion, so that the concentration of iron supply water can be maintained at a low level of 1 ppb or less.

Further, the corrosion potential of the steam generator heat transfer tube 27 is reduced by a pressure pump 26 from the hydrogen gas supplied from the hydrogen gas supply device 25 to −200 mV as an indication value of the corrosion potential meter 28 branched from the steam generator 1. It is supplied to the downstream side of the HFF 9 as follows.

Further, a noble metal is injected into the steam generator 1 by a noble metal solution injection device 29, and the noble metal is adhered to the surface of the steam generator heat transfer tube 27, thereby promoting the reaction between the supplied oxygen gas and the supplied hydrogen gas. The gas supply can be saved. On the other hand, by providing an exhaust gas recombiner 31 that reacts hydrogen gas and oxygen gas into water in the exhaust gas system 30, the supplied hydrogen gas and oxygen gas can be safely processed.

According to the present embodiment, the steam generator heat transfer tube
In addition to maintaining and improving the material soundness of No. 28, the use of no chemicals is not only advantageous in economics, but also has a favorable effect on the human body and the environment.

A second embodiment according to the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in that a condensate desalination device 32 is connected downstream of the HFF 9, and a condensate desalination device bypass pipe 33 is provided before and after this condensate desalination device 32. In addition, an HFF upstream return pipe 34 is provided between the LPPD 20 connected to the secondary side of the low-pressure feed water heater 10 and the discharge pipe of the condensate pump 8.

The HFF upstream return pipe 34 is connected to a condensate desalination device upstream return pipe 35 via an upstream return valve 38 to the downstream pipe of the HFF 9.
Are connected via the downstream return valve 39.

In this embodiment, the condensate desalination unit 32 installed downstream of the HFF 9 is a mixed-bed type condensate desalination unit using a granular ion exchange resin. This condensate desalination device 32 can remove impurities mixed during the shutdown of the power generation turbine plant during condensate and feedwater purification before starting the plant, can suppress deterioration of reactor water quality at the initial stage of plant startup, and maintain extremely high purity. it can. It is also possible to deal with seawater leaks. Furthermore, rational operation can be performed by bypassing the condensate desalination device 32 using the bypass line 33.

The iron concentration of the LPPD 20 increases depending on the start-up of the plant. If the iron concentration of the feed water can exceed 1 ppb, the return of the LPPD 20 is performed upstream of the HFF 9 or upstream of the HFF 9 and the condensate desalination unit 32. Valves 37, 38, and 39 are installed so that they can be returned anywhere during the period 35 or downstream of the condensate desalination unit 32, and these valves are switched to operate rationally so that the iron supply water concentration is 1 ppb or less. be able to.

The HFF upstream return pipes 34, HFF9, the condensate desalination unit upstream return pipe 35, and the condensate desalination unit downstream return pipe 36 may be configured with a minimum combination for streamlining the plant. .

[0047]

According to the present invention, the concentration of iron feedwater can be maintained at a low level of 1 ppb or less without using a chemical, and the corrosion potential on the secondary side of the steam generator heat transfer tube can be reduced by -200 m.
V or less, which not only can maintain and improve the material integrity of the steam generator heat transfer tubes, but also improve the economics of using no chemicals and make the adverse effects on the human body and the environment gentle. Can be.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of a power generation turbine facility according to the present invention.

FIG. 2 is a system diagram showing a second embodiment of the power generation turbine equipment according to the present invention.

FIG. 3 is a curve diagram showing the effect of inhibiting the corrosion of dissolved oxygen material to compare the operation of the present invention with the conventional example.

FIG. 4 is a curve diagram showing the effect of dissolved oxygen on corrosive wear overspeeded at a flow rate.

FIG. 5 is a curve diagram showing the effect of the steam flow rate on the erosion and corrosion reduction of the corrosion-resistant material.

FIG. 6 is a curve diagram showing the effect of steam wetness on the erosion and corrosion loss of a corrosion-resistant material.

FIG. 7 is a curve diagram showing the effect of steam humidity on the erosion and corrosion loss of a corrosion-resistant material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Steam generator, 2 ... Main steam pipe, 3 ... High pressure turbine, 4
... Moisture separator, 5 ... Reheater, 6 ... Low pressure turbine, 7 ... Main condenser, 8 ... Condenser pump, 9 ... Condensed hollow fiber membrane filter (HFF), 10 ... Low pressure feed water heater, 11 ... water pump, 12
… High pressure feed water heater, 13… feed water pipe, 14… bleed pipe, 15… moisture separator drain pipe, 16… reheater drain pipe, 17… high pressure heater drain pipe, 18… high pressure heater drain pump, 19… bleed pipe , 20… Low pressure heater drain bypass pipe (LPPD), 21
... Low pressure heater drain pump, 22 ... Oxygen gas or air supply device, 23 ... Main steam pressurization pump, 24 ... Water supply system, 25 ... Hydrogen gas supply device, 26 ... Hydrogen gas pressurization pump, 27 ... Heat transfer tube, 28 ... Corrosion potentiometer, 29 ... Precious metal injection device, 30 ... Exhaust gas system, 31 ... Exhaust gas recombiner, 32 ... Condensate desalination device, 33 ... Condensate desalination device bypass pipe, 34 ... HFF upstream return pipe, 35 ... Condensate desalination unit upstream return pipe, 36 ... condensate desalination unit downstream return pipe, 37 ... HFF upstream return valve, 38 ... condensate desalination unit upstream return valve, 39 ... condensate desalination unit downstream return valve.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FIG21D 1/00 S

Claims (8)

[Claims] 1. A steam generated from a steam generator or a boiler is guided to a turbine system through a main steam pipe, and a turbine of the turbine system is rotated to drive a generator to generate electric power, thereby completing work in the turbine system. The steam is condensed and condensed by a condenser of a condensing system, the condensed water is purified by a condensate purifying system, and heated by a feed water heater of a water supply system to supply water, and the supplied water is the steam generator or the boiler. In the turbine facility for power generation, the feed water is adjusted to a concentration of 7 ppb or more with neutral pure water, and corrosion-resistant materials are incorporated in some of the equipment and piping from the steam generator or boiler to the feed water system. Turbine equipment for power generation characterized by the following. 2. The turbine facility for power generation according to claim 1, wherein the iron concentration of the water supply in the water supply system is 1 ppb or less. 3. The turbine equipment for power generation according to claim 1, wherein an oxygen gas supply pipe is connected to an upstream pipe of the main steam pipe and a low-pressure feedwater heater of the feedwater system. 4. The turbine facility for power generation according to claim 1, wherein said corrosion-resistant material is made of weather-resistant steel, low-alloy steel or stainless steel. 5. The condensate purification system has at least one of a condensate filter and a condensate desalination device, and the condensate filter is any one of a hollow fiber membrane filter, a non-precoated filter and a powder ion exchange resin filter. The turbine equipment for power generation according to claim 1, wherein the turbine equipment comprises one of the following. 6. A discharge side pipe of the condensate condensate pump and a low pressure heater drain side of the low pressure feed water heater of the water supply system are connected by a low pressure heater drain pipe, a low pressure heater drain pump, and an upstream return pipe of a hollow fiber membrane filter. 2. The power generation system according to claim 1, wherein an upstream return pipe and a downstream return pipe of a condensate desalination apparatus are connected to the upstream return pipe of the hollow fiber membrane filter and the downstream pipe of the low-pressure feedwater heater. Turbine equipment. 7. The turbine plant for power generation according to claim 1, wherein a noble metal injection device is connected to the steam generator or the boiler. 8. A hydrogen gas supply device is connected to a downstream water supply system pipe of the condensate desalination device to maintain a corrosion potential on the secondary side of the steam generator or the boiler at an amount of -200 mV or less. The turbine equipment for power generation according to claim 1, wherein the turbine equipment comprises: