JP3184016B2 - Long-term storage of turbine cycle equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long-term storage method for turbine cycle equipment.

[0002]

2. Description of the Related Art Generally, the term "long-term storage of a power plant" refers to stopping the operation of a power plant for a long period of time and preparing for the next start of operation while preventing generation of rust and the like. Among the power plants, the turbine cycle equipment, namely the condenser,
Conventional methods for long-term storage of condensate pumps, feed water heaters, deaerators, feed pumps, and piping connecting these devices include (1) nitrogen seal storage, (2) natural drying storage,
(3) There is full storage.

[0003] Among the above, (1) nitrogen-sealed storage is to perform long-term storage by enclosing nitrogen in equipment and piping of a turbine cycle that can be isolated from the atmosphere. Then, nitrogen seal pipes are connected to some parts of the equipment and the pipes via stop valves, and each nitrogen seal pipe is connected to a nitrogen gas supply source.

[0004] After the plant is stopped, water such as feed water and condensate remaining in the turbine cycle system is drained, and a stop valve is opened to fill the turbine cycle system with nitrogen gas. However, pumps such as feed water pumps and condensate pumps have a gland, from which nitrogen gas leaks to the atmosphere, close the front and rear valves of each pump to prevent nitrogen gas from leaking to the atmosphere through the pumps Like that.

[0005] Further, (2) natural drying storage is applied to equipment and places where isolation from the atmosphere is difficult and (1) nitrogen sealed storage cannot be performed. In this case, the equipment is completely drained and stored for a long time as it is. (3) Full-water storage is applied to equipment that cannot completely drain water. That is, the apparatus is intended for equipment such as a condensate pump and a condensate desalination apparatus, and performs long-term storage by filling with water whose pH has been adjusted by a chemical such as hydrazine or water charged with a rust preventive inhibitor. .

[0006] In practice, long-term storage of a turbine cycle consists of (1) nitrogen sealed storage, (2) natural drying storage, and (3)
It is done by a combination of full storage.

FIG. 4 is a system diagram of this kind of turbine cycle equipment provided with long-term storage means.

In the figure, turbine cycle equipment includes a high-pressure turbine 1, an intermediate-pressure turbine 2, a low-pressure turbine 3, a condenser 4,
Condensate pump 5, ground steam condenser 6, low pressure feed water heater 7, deaerator 8, deaerator storage tank 9, feed pump 10,
It is composed of a high-pressure feedwater heater 11, and a turbine cycle system is formed by these turbine cycle devices.

In this turbine cycle system, a nitrogen seal pipe 51a is connected to the inlet side of the main steam stop valve 13 of the high-pressure reheat steam pipe 12 through a stop valve 52a as shown by a chain line in FIG. A nitrogen seal pipe 51b is connected to the condenser pipe 14 of the condenser 6 and the low-pressure feed water heater 7 via a stop valve 52b.

Further, a nitrogen seal pipe 51c is connected to a water supply pipe 15 between the water supply pump 10 and the high-pressure water heater 11 via a stop valve 52c. The nitrogen seal pipes 51 a, 51 b, and 51 c merge to connect the main nitrogen seal pipe 51 to a nitrogen gas supply cylinder 54 via a pressure adjusting valve 53.

When the plant is stored for a long time after the shutdown, water such as feed water and condensate remaining in the turbine cycle system is drained. Subsequently, the stop valves 24a, 24
b, 24c and 24d are closed, and the check valve 16 is also closed. And each stop valve 52a, 52b, 52c
Is opened, and the pressure regulating valve 53 is gradually opened. This allows
Nitrogen is supplied to a part of the high-pressure turbine 1 with a nitrogen seal pipe 51a.
And the nitrogen is supplied to the low-pressure feed water heater 7 and the condensate pipe 14.
And the nitrogen is supplied to the water supply pipe 15 and the high-pressure water heater 11 by the stop valve 52c.

In this case, the pressure of the nitrogen gas is maintained at an appropriate value by the pressure regulating valve 53. In addition, pumps, such as a condensate pump 5 and a water supply pump 10, have a gland part,
Since nitrogen gas leaks into the atmosphere, the first and second half of each pump is closed to prevent nitrogen gas from leaking into the atmosphere via the pumps.

Next, the condenser water chamber 4a, the condensate booster pump and the water supply booster pump (not shown), and the water supply pump 10 perform the natural drying storage of (2), and completely drainage of the equipment is stored for a long period of time. .

The condensate pump 5 and a condensate desalination apparatus (not shown) perform the full storage of (3) and fill the water adjusted to pH with a chemical such as hydrazine, or charged with a rust inhibitor inhibitor. To

[0015]

However, the conventional methods of long-term storage, namely, nitrogen sealed storage, naturally dried storage, and full water storage have the following various problems.

First, in the case of nitrogen sealed storage, a) there are not so many devices and pipes in the turbine cycle that can be completely isolated from the atmosphere, and the application range is limited. b) Since the isolation is performed by closing the valve, nitrogen gas is consumed by leakage from the valve gland and the seat. In long-term storage, the consumption of this nitrogen gas is not negligible. c) If moisture remains in the system and equipment, there is local rust on that part.

In the case of natural drying storage, a) there is a high possibility that dew condensation will occur inside the device due to a change in atmospheric temperature.
There is local rust on the condensation part. b) If moisture remains in the system and equipment, there is local rust on that part. c) Rust prevention effect is clearly inferior to nitrogen sealed storage.

[0018] In the full storage, a) there is a possibility of freezing due to the atmospheric temperature and destruction of the equipment. b) It is difficult to control the concentration of hydrazine. If the concentration is low, the rust prevention effect is insufficient, and if the concentration is high, the generation of ammonia causes corrosion of the copper alloy.
c) Drainage treatment of hydrazine water after storage is necessary and difficult.

Due to the above problems. It is difficult to store the turbine cycle inexpensively and without significant rust for a long period of time.

An object of the present invention is to provide a method for long-term storage of turbine cycle equipment, which eliminates the above-mentioned problems and enables low-cost storage of the turbine cycle without rusting.

[0021]

SUMMARY OF THE INVENTION The present invention divides turbine cycle equipment, which is systemized by connecting pipes to various devices, into a plurality of small systems each including a device, and one end of each of the divided small systems. Is connected to a temporary dry air supply pipe that supplies dry air from an air drying blower,
At the other end of each of the small systems, a temporary dry air return pipe for returning the dry air to the air drying blower is connected, and while the dry air is circulated and supplied from the air drying blower to the small system, the outside air humidity The air drying blower is automatically operated and stopped according to

[0022]

[0023]

[0024]

According to the above configuration, dry air circulates in each small system dividing the turbine cycle equipment. At this time, even if there is a part communicating with the inside of the system and the outside air,
While the dry air is circulating, the dry air does not leak out of the system, so that the outside air does not enter the system and raise the internal humidity. On the other hand, when the outside air humidity is low, the outside air may enter the system by stopping the air drying blower. This keeps the inside of the system dry at all times, preventing rusting,
By appropriately stopping the air drying blower, energy saving and long life can be achieved.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram of a long-term storage device for turbine cycle equipment according to an embodiment of the present invention. The same reference numerals as in FIG. 4 in which FIG. 1 shows a conventional example indicate the same or corresponding parts, and the turbine cycle equipment is the same as in FIG. In the figure, there are provided means divided into four blocks from a first block long-term storage means 60 to a fourth block long-term storage means 63 corresponding to the turbine cycle equipment.

The first block long-term storage means 60 has an air drying blower 60a comprising an air dryer and a blower,
The temporary dry air supply pipe 60b is connected to the reheat steam valve 22 provided in the high temperature reheat steam pipe 21, and the temporary dry air return pipe 60c is connected to the low pressure feed water heater 7.

The second block long-term storage means 61 has an air drying blower 61a, a temporary drying air supply pipe 61b is connected to the main steam stop valve 13 provided in the high pressure reheat steam pipe 12, and a temporary drying air return pipe is provided. 61 c is connected to the check valve 16.

The third block long-term storage means 62 has an air drying blower 62a, a temporary drying air supply pipe 62b is connected to the high pressure water heater 11, and a temporary drying air return pipe 62c is connected to the deaerator storage tank 9. It is connected to a water supply pipe 15 between the water supply pump 10.

The fourth block long-term storage means 63 has a temporary dry air supply pipe 63a.
3b is connected to the check valve 17 and the temporary dry air return pipe 6
3c is connected to the check valve 18.

Reference numerals 60d, 61d, 62d, 63d denote atmospheric suction valves, 60e, 61e, 62e, 63e denote orifices, 9a a stopper at the bottom of the deaerator storage tank 9, and 23 a ground steam regulating valve. It is.

The first block long-term storage means 60 will be specifically described with reference to FIG.
The temporary dry air supply pipe 60b is connected to the main steam stop valve 2 and the reheat steam valve 22 from the discharge section a. Further, the temporary drying air return pipe 60c is connected from the water chamber of the low pressure feed water heater 7 to the suction part of the air drying blower 60a.

The temporary dry air return pipe 60c is provided with an orifice 60e for adjusting pressure and an atmospheric suction valve 60d. The relative humidity switch 60f is installed at an appropriate position in a small system, and an air drying blower 60a is set at an arbitrary relative humidity.
Can be automatically operated and stopped.

The equipment to be dried and stored by the first block long-term storage means 60 is the medium pressure turbine 2, the low pressure turbine 3, the low pressure feed water heater 7, the body side of the condenser 4, the condensate pump 5, and the like. Sealing with other small systems is performed by closing an appropriate stop valve or shutting off with a temporary jig. Here, a temporary jig is provided on the reheat steam valve 22, and the stop valve 24a on the water supply pipe to the deaerator is closed to isolate the small system.

Next, the operation of this embodiment will be described for the first block long-term storage means 60.

First, the air is sucked by the air drying blower 60a, the moisture in the air is removed, and the air whose relative humidity is sufficiently reduced at the discharge portion passes through the temporary dry air supply pipe 60b and the reheat steam valve 22 Main steam stop valve 13
It is sent into the system.

This dry air passes through the medium pressure turbine 2, the low pressure turbine 3, the body side of the condenser 4, the condensate pump 5, and the low pressure feed water heater 7, and temporarily goes from the water chamber of the final low pressure feed water heater 7. It is discharged to the dry air return pipe 60c. During this time, the dry air absorbs the moisture remaining in the system, and its relative humidity gradually increases, but returns to the air drying blower 60a to remove the absorbed moisture to the outside of the system. Thereafter, the above cycle storage period is repeated.

Here, the air drying blower 60a can always be operated, but when the relative humidity of the outside air is low, the relative humidity in the small system is maintained at 30% or less even if the air drying blower 60a is stopped. can do. Therefore,
Set the relative humidity switch 60 to an appropriate relative humidity value of about 20%.
f is set, and when the relative humidity rises beyond the set value, the air drying blower 60a is automatically started to reduce the increased relative humidity. Similarly, when the relative humidity is sufficiently reduced, the air drying blower 60a is automatically stopped.

In storage with this configuration, the most rust-producing materials constituting the turbine cycle system are carbon steel and copper alloy, and these materials are generally in the atmosphere when the relative humidity exceeds 50%. Paying attention to the point that rust easily occurs, the content can be suppressed to 30% or less. Therefore, the relative humidity of the air in the turbine cycle system is reduced by 30%.
It is always kept below and can be stored for a long time with almost no occurrence of rust.

Incidentally, the turbine cycle system is not completely sealed, and communicates with the outside air through a pump, a turbine, a gland of a valve, and the like. In order to prevent external air from entering the system and increasing the relative humidity of the air in the system, the pressure in the system needs to be higher than the atmospheric pressure in all places.

The air drying blower 60a has a built-in blower therein, whereby the dry air is circulated through the small system, so that the pressure distribution in the system is as shown in FIG.

That is, near the air suction valve 60d on the inlet side of the air drying blower 60a sucks air at a pressure P1 lower than the atmospheric pressure, and on the outlet side of the air drying blower 60a, the dry air is temporarily dried by the high pressure P2. Supply piping 60b
At the outlet side of the turbine cycle device, the pressure P decreases to a pressure P3, and the temporary dry air return pipe 60c causes the orifice 60 to pass through.
Return via e. At this time, since the air is throttled by the orifice 60e, the air maintains a high atmospheric pressure P4 on the upstream side, and the pressure becomes P5 near the atmospheric suction valve 60d and returns to the pressure P1 of the air drying blower 60a.

The first block long-term storage means 60 has been described above.
The same applies to the block long-term storage means 63.

As described above, this embodiment has the following effects on long-term storage of turbine cycle equipment.

(1) Since dry air having a sufficiently low relative humidity always circulates in the turbine cycle, even if non-dischargeable drain water remains in the system before long-term storage, immediately after long-term storage is started. These residual drain waters evaporate and are dried.

(2) Even if there is a place that cannot be sealed with the outside air, such as a gland, the dry air always leaks from the inside of the turbine cycle to the outside air by maintaining the inside of the turbine cycle at atmospheric pressure or higher. Therefore, the outside air does not enter the turbine cycle and does not increase the relative humidity of the air in the turbine cycle. Air flowing out to the outside air is air, which is very inexpensive compared to nitrogen gas and so on. Applicable.

(3) It is possible to perform automatic operation such that the relative humidity is always kept below an arbitrary value, and long-term storage of the turbine cycle can be performed at low operation cost.

(4) Difficult adjustment of pH and the like at the time of full storage is unnecessary, and management during long-term storage becomes easy. Further, there is no problem such as drain water treatment after storage.

(5) Since dry air is used, the inside of the device can be inspected during long-term storage, and recovery is extremely simple. Also, since nitrogen gas is not used, there is no danger such as oxygen deficiency during inspection.

In the present embodiment, the turbine cycle equipment is divided into four parts, but various ways of dividing the turbine cycle into a plurality of small systems are conceivable. It should be selected so that the flow of dry air is not interrupted as much as possible. Also,
These small systems are divided into stop valves and the like. If opening and closing are easy, the pattern of the flow of dry air can be changed by opening and closing the stop valves periodically.

[0051]

As described above, according to the present invention, the turbine cycle equipment is divided into a plurality of small systems, each of which is provided with an air drying blower to circulate the dry air. As a result, there is no place where the air stagnates, and the entire inside of the equipment is always kept in a dry state to prevent rusting, and long-term storage of the turbine cycle equipment can be economically realized. Further, when the outside air humidity is low, each air drying blower is automatically stopped, so that energy saving and long life of the air drying blower can be achieved.

[Brief description of the drawings]

FIG. 1 is a system diagram including a long-term storage means in a turbine cycle facility of a power plant showing an embodiment of the present invention.

FIG. 2 is a system diagram of a first block long-term storage means of FIG. 1;

FIG. 3 is an explanatory diagram showing a pressure distribution of dry air in a first block long-term storage means of FIG. 1;

FIG. 4 is a system diagram including a long-term storage means for a turbine cycle device of a power plant showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 High-pressure turbine 2 Medium-pressure turbine 3 Low-pressure turbine 4 Condenser 5 Condenser pump 7 Low-pressure feedwater heater 8 Deaerator 9 Deaerator storage tank 10 Feedwater pump 11 High-pressure feedwater heater 12 High-pressure reheat steam pipe 13 Main steam Stop valve 14 Condensate pipe 15 Water supply pipe 21 High temperature reheat steam pipe 22 Reheat steam valve 60 First block long-term storage means 61 Second block long-term storage means 62 Third block long-term storage means 63 Fourth block long-term storage means 60a, 61a, 62a, 63a Air drying blower 60b, 61b, 62b, 63b Temporary dry air supply pipe 60c, 61c, 62c, 63c Temporary dry air return pipe 60d, 61d, 62d, 63d Atmospheric suction valve 60e, 61e, 62e, 63e Orifice 60f, 61f, 62f, 63f relative humidity switch

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01K 13/00 F01D 25/00

Claims (1)

(57) [Claims] 1. A long-term storage method for a turbine cycle facility in which operation of a power plant is stopped and operation is resumed after a long-term stoppage, wherein pipes are connected to various devices, and the systemized turbine cycle devices are individually installed. Divided into multiple small systems,
At one end of each of the divided small systems, a temporary dry air supply pipe for supplying dry air from an air drying blower is connected, and at the other end of each of the small systems, dry air is supplied to the air drying blower. A temporary dry air return pipe is connected to return dry air from the air dry blower to the small system in a circulating manner, and the air dry blower is automatically operated and stopped according to outside air humidity. A long-term storage method for turbine cycle equipment, characterized in that: