JP2001140606A - Turbine gland leak-off steam recovering system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid such a problem that moisture is mixed with turbine bearing oil by actively recovering turbine gland leak-off steam instead of a gland steam condenser at the time of such emergency that an external power supply is eliminated. SOLUTION: In a steam turbine device provided with a gland steam condenser 8 for recovering stem leaked from turbine gland parts G1 to G6 in a drain condition as well as supplying gland steam for sealing the turbine gland parts G1 to G6, a steam ejector 30 and the like are interposed in a leak line 7 of the leak-off steam as an emergency recovering means, and the leak-off steam is actively discharged or recovered instead of the gland steam condenser 8 when the external power supply is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recovering steam leaked from a turbine gland of a steam turbine in a thermal or nuclear power plant.

[0002]

2. Description of the Related Art In this type of steam turbine device, a portion where a turbine rotating shaft penetrates a turbine casing is referred to as a ground, and a labyrinth fin structure is provided to prevent leakage of air from the outside or outflow of steam to the outside. The ground steam is supplied from the outside to seal the portion, and the steam leaking from the gland is drained and collected to drain the steam. It is well known that a capacitor is provided.

For example, as shown in FIG. 5, in addition to the high-pressure turbine 1 and the low-pressure turbine 2, each of the glands G1 to G6 of the feed pump driving turbine 3 is provided with a boiler or a nuclear power plant (pressurized water type) in a thermal power plant. Main steam (e.g., equivalent to about 60 kg / cm ² ) from a steam generator or the like (not shown) in a primary reactor (having a nuclear reactor) is supplied to a primary pressure reducing valve (pressure control valve) 5 and 2 provided in a feed line 4. Next, the pressure is reduced to a predetermined pressure (for example, about 0.3 kg / cm ² ) through the pressure reducing valves 6a to 6d and supplied.

On the other hand, each of the ground portions G1 to G6 is connected to a ground steam condenser 8 via a leak line 7, and under the negative pressure of about -400 to -600 mmAq due to the rotation of the exhaust fan 9, the ground portions G1 to G6 are connected. Leakage vapor from G6 is sucked.

[0005] The ground steam condenser 8 is usually provided with a condenser (not shown) for condensing and recovering steam discharged from the high-pressure turbine 1, the low-pressure turbine 2 and the feed pump driving turbine 3 as cooling water. And is supplied by a condensate pump 10.

In the figure, reference numeral 11 denotes an auxiliary for supplying auxiliary steam from an auxiliary steam supply source (not shown) to each of the ground sections G1 to G6 at the time of plant startup, instead of the main steam from the steam generation source during warming. Steam supply line, 12
Is a control valve that is opened to recover spillover steam when the high-pressure turbine 1 is under a high load to the low-pressure heater.

In this way, the gland steam is supplied to the gland portions G1 to G6 of the high-pressure turbine 1, the low-pressure turbine 2 and the feed water pump driving turbine 3, so that a good sealing function is exhibited. As a result, a low-temperature atmosphere flows into the turbine, the turbine is rapidly cooled, and the rotating part and the stationary part come into contact with each other, thereby avoiding problems such as damage to the turbine, thereby maintaining normal operation of the turbine.

[0008]

By the way, the exhaust fan 9 and the condensing pump 10 in the above-mentioned gland leakage steam recovery apparatus are usually driven by electric power from an external power supply. Therefore, when the external power supply is lost during the operation of the plant (due to a power failure, etc.), the exhaust fan 9 and the condensate pump 10 are stopped, and the function of the ground leakage steam recovery device (gland steam condenser 8) may be lost. become.

As a result, the ground steam supplied to each of the ground portions G1 to G6 has no recovery destination, and leaks out of each of the ground portions G1 to G6 to the outside and the inside of the turbine. Then, the leaked steam is blown to the bearings adjacent to the respective glands G1 to G6, and moisture is mixed into the bearing oil (see FIG. 3B). However, there is a problem that the number of work steps and costs are increased.

Since the exhaust fan 9 consumes a small amount of power, some plants can supply power from an emergency power supply system. In this case, the exhaust fan 9 continues even if external power is lost. And can be driven. However,
Since the cooling water is not supplied due to the stoppage of the condensate pump 10, the function of the gland leakage steam recovery device (gland steam condensate 8) cannot be said to be sufficient, and the possibility that moisture is mixed in the above-described bearing oil cannot be denied. This is the current situation.

Accordingly, an object of the present invention is to solve the problem that water leaks into turbine bearing oil by actively recovering steam leaked from the turbine ground in place of a ground steam condenser in the event of an emergency such as loss of external power. Another object of the present invention is to provide a turbine gland leakage steam recovery device that can be avoided.

[0012]

According to the present invention, there is provided a turbine gland leakage steam recovery apparatus for solving the above-mentioned problems.
In a steam turbine device provided with a gland steam condenser for supplying gland steam for sealing a turbine gland portion and draining and collecting leaked steam leaking from the gland portion, a leak line for the leaked steam is provided. An emergency recovery means for actively collecting the leaked steam in place of the ground steam condenser in an emergency is provided.

[0013] The emergency recovery means discharges the leaked steam to the atmosphere via suction means.

Further, the suction means is an ejector for ejecting a pressurized fluid from a nozzle to suck and discharge surrounding leaked steam.

[0015] The suction means is a steam ejector driven by main steam from a steam generation source of the steam turbine device, and has an on-off valve interposed in a main steam line to the steam ejector and the same steam as an on-off valve. The on-off valve interposed in the steam line leaking to the ejector is opened when external power is lost.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A turbine gland leaking steam recovery device according to the present invention will be described in detail below with reference to the drawings by way of an embodiment.

[Embodiment] FIG. 1 is a schematic configuration diagram of a turbine gland leakage steam recovery apparatus showing one embodiment of the present invention, and FIG.
3 is a half sectional view of a high-pressure turbine, etc., and FIG. 3 is an explanatory view of an operation in a gland portion. FIG. 3A shows an operation state in a normal operation, and FIG. 4A and 4B are explanatory views of the operation of the water seal valve, wherein FIG. 4A shows the valve closed state, and FIG. 4B shows the valve open state. In these figures, the same members and portions as those in FIG. 5 used as a conventional example are denoted by the same reference numerals, and detailed description will be omitted.

As shown in FIG. 1, steam generation in a nuclear power plant (having a pressurized water reactor) is provided in each of the glands G1 to G6 of the feed water pump driving turbine 3 in addition to the high pressure turbine 1 and the low pressure turbine 2. Main steam from a steam generation source (not shown) such as a vessel is reduced to a predetermined pressure and supplied through a primary pressure reducing valve 5 and secondary pressure reducing valves 6 a to 6 d provided in a feed line 4.

On the other hand, each of the ground sections G1 to G6 is connected to a ground steam condenser 8 via a leak line 7, and is connected to the ground section G1 to G6 under a negative pressure caused by rotation of an exhaust fan 9 driven by an external power supply. Leakage vapor is sucked.

The ground steam condenser 8 is provided with a condenser (not shown) for condensing and recovering steam discharged from the high-pressure turbine 1, the low-pressure turbine 2 and the feed water pump driving turbine 3 as cooling water. Condensate is used and supplied by a condensate pump 10 driven by an external power supply.

The high-pressure turbine 1 and the low-pressure turbine 2
As shown in FIG. 2, a double flow type is used.
That is, in FIG. 2, reference numeral 20 denotes an outer casing, 21 denotes an inner casing, and 22 denotes a steam supply port, which is disposed upstream through a steam generating source (when the turbine is the high-pressure turbine 1) and a crossover pipe. Steam supplied from the high-pressure turbine 1 (when the turbine is the low-pressure turbine 2) is taken in from this position. Therefore, the steam supplied from the steam supply port 22 is divided into two parts from the left and right, and is sent to the downstream side through each of the symmetrically arranged paragraphs.

Reference numeral 23 denotes a blade ring, which is divided into a plurality of sections so as to support a plurality of stages of stationary blades 24. In addition, each stationary blade 2
A plurality of rotor blades 25 are arranged downstream of each of the plurality of blades 25 corresponding to each of the four blades. The rotor blades 25 are provided on a rotor 27 supported by left and right bearings 26, and form a basic form as the high-pressure or low-pressure turbines 1, 2. still,
Reference numeral 28 denotes an atmospheric discharge plate as a safety device for preventing the complete collapse of the turbine, and reference numeral 29 denotes an exhaust port which communicates with the condenser (not shown). On the other hand, the feed pump driving turbine 3
A pressure double turbine (multi-stage turbine) or the like is used.

The configuration of the ordinary steam turbine apparatus has been described so far. The feature of this embodiment is, as shown in FIG. 1, that the leaked steam is supplied to the aforementioned leak line 7 when the external power supply is lost (emergency). The point is that an emergency recovery means for positively recovering is provided instead of the ground steam condenser 8.

More specifically, a steam ejector 30 is provided as suction means for leaking steam, and a main steam line branched from a feed line 4 upstream of the primary pressure reducing valve 5 from a nozzle (not shown) of the steam ejector 30. The main steam (drive steam) is jetted through the steam ejector 31 while the steam ejector 30
In the bleed air chamber (not shown), the ground steam condenser 8 is provided.
Leaked steam line 32 branched from leak line 7 in front
The leaked steam flows through the outlet steam, and the leaked steam is sucked and mixed into the jet steam and is safely discharged to the atmosphere through the silencer 33.

The main steam line 31 is provided with an on-off valve 34 which is an electric valve and a pressure control valve 35 which is an air-operated valve located downstream thereof. An on-off valve 36 serving as an air-operated valve is interposed.

The on-off valve 34 is connected to the controller 3
7, when the external power supply is lost, the controller 37 detects this and the on-off valve 34 is opened.

With this configuration, during normal operation of the plant where external power is not lost, the on-off valve 34 is kept closed by the controller 37, so that the steam ejector 3
While 0 does not work, the exhaust fan 9 and the condensate pump 10 of the ground steam condenser 8 function normally by being driven by an external power supply.

As a result, as shown in FIG.
Main steam from a steam generation source is supplied to the gland sections G1 to G6 of the high-pressure turbine 1, the low-pressure turbine 2, and the feedwater pump driving turbine 3 via the feed line 4, while the gland sections G1 to G6 are provided. The steam leaked from is sucked into the ground steam condenser 8 through the leak line 7, where it is condensed and drained and collected.

Thus, each of the ground portions G1 to G6
In the, while the ground steam is supplied, a good sealing function is exhibited, and leakage of air from the outside is prevented,
The outflow of steam to the outside is prevented.

On the other hand, when an external power supply is lost due to a power failure or the like, the exhaust fan 9 and the condensate pump 10 driven by the external power supply are stopped, and the function of the ground steam condenser 8 is lost. Thereby, the on-off valve 34 of the main steam line 31 is opened, and the main steam from the feed line 4 is supplied to the steam ejector 30 as the driving steam.

At this time, the driving steam is always supplied to the steam ejector 30 while being controlled at a constant pressure (for example, about 10 kg / cm ² ) by the pressure control valve 35. The pressure control by the pressure control valve 35 is particularly necessary. is not.

By the operation of the steam ejector 30, the on-off valve 36 of the leaked steam line 32 is automatically opened. still,
The on-off valve 36 may be opened by a signal from the controller 37.

As a result, each of the ground sections G1 to G1
The leaked steam from the G6 is sucked into the steam ejector 30 instead of the ground steam condenser 8, and is safely discharged and collected from here to the atmosphere via the silencer 33.

As a result, even at the time of the abnormality, as shown in FIG. 3A, the ground steam is supplied to each of the ground portions G1 to G6 so that the sealing function can be effectively performed.

In other words, when there is no backup by the steam ejector 30, as shown in FIG. 3 (b), due to the loss of the function of the ground steam condenser 8, the steam is supplied to each of the ground sections G1 to G6. Since the collected ground steam has no recovery destination, it leaks out of each of the glands G1 to G6 to the outside and the inside of the turbine, and the leaked steam is blown to the bearing 26 adjacent to each of the glands G1 to G6. As a result, water is mixed into the bearing oil.

As described above, in the present embodiment, even in the case of the abnormality, each of the ground portions G1 to G5 can be effectively used by effectively utilizing the steam supply capability of the steam generator or the like by the residual heat of the steam generation source.
G6 can be continuously supplied to G6, and problems such as mixing of water in bearing oil can be avoided.

In the above embodiment, the on-off valve 36 interposed in the leaked steam line 32 may be replaced with a water seal valve 40 shown in FIG. That is, in the water seal valve 40, when the steam ejector 30 to which the driving steam is not supplied is not operated, the leaked steam line 32 is sealed (see FIG. 4A), and the driving steam is supplied on the contrary. When the steam ejector 30 operates, the water seal of the leaked steam line 432 is opened, and the leaked steam is sucked into the steam ejector 30.

A plurality of steam ejectors 30 may be provided in parallel.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the spirit of the present invention. For example, an ejector using air, nitrogen, or the like as a driving source may be used instead of the steam ejector 30. Of course, the steam from the emergency steam generation source may be used as the driving steam for the steam ejector 30 instead of the main steam from the steam generation source such as the steam generator described above.

Further, as a means for sucking the leaked steam, an exhaust pump or an exhaust fan driven by an emergency steam turbine or the like may be used instead of the steam ejector.

Instead of discharging the leaked steam to the atmosphere through the steam ejector 30, the leaked steam line 32 is connected to the high-pressure turbine 1, the low-pressure turbine 2, and the steam discharged from the feed water pump driving turbine 3 to condense and recover the steam. Alternatively, the on-off valve 36 may be opened in an emergency and collected in the condenser for a predetermined period of time.

[0042]

As described above, according to the first aspect of the present invention, a gland for supplying gland steam for sealing a turbine gland and for draining and collecting leaked steam leaking from the gland. In the steam turbine device provided with the steam condenser, the leak line of the leaked steam is provided with emergency recovery means for actively collecting the leaked steam instead of the ground steam condenser in an emergency. The function of recovering steam leaked from the turbine gland can be maintained in an emergency such as loss, and the steam sealing function of the gland can be maintained well to avoid problems such as mixing of water into turbine bearing oil. .

According to the second aspect of the present invention, the emergency recovery means discharges the leaked steam to the atmosphere via the suction means. There is an advantage that various structures can be used.

According to the third aspect of the present invention, the suction means is an ejector for ejecting a pressurized fluid from a nozzle to suction and discharge surrounding leaked steam. Therefore, there is an advantage that various things can be used as a drive source of the ejector.

According to a fourth aspect of the present invention, the suction means is a steam ejector driven by main steam from a steam generation source of the steam turbine device, and is interposed in a main steam line to the steam ejector. The opened / closed valve and the on / off valve interposed in the steam line leaking to the steam ejector are opened when the external power supply is lost, so that in addition to the actions and effects of claim 1, the remaining steam generation source such as a steam generator is provided. There is an advantage that the steam supply capability by heat can be effectively used as a drive source of the steam ejector.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a turbine gland leaking steam recovery device showing one embodiment of the present invention.

FIG. 2 is a half sectional view of a high-pressure turbine and the like.

FIGS. 3A and 3B are explanatory diagrams of the operation in the ground portion, wherein FIG. 3A shows the operation state during normal operation, and FIG.

4 (a) and 4 (b) are views for explaining the operation of the water seal valve, wherein FIG. 4 (a) shows the valve closed state and FIG. 4 (b) shows the valve open state.

FIG. 5 is a schematic configuration diagram of a conventional turbine gland leaking steam recovery device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 high-pressure turbine 2 low-pressure turbine 3 feedwater pump driving turbine 4 feed line 5 primary pressure reducing valve 6 a to 6 d secondary pressure reducing valve 7 leak line 8 ground steam condenser 9 exhaust fan 10 condensate pump 11 auxiliary steam supply line 12 control valve REFERENCE SIGNS LIST 20 outer casing 21 inner casing 22 steam supply port 23 blade ring 24 stationary blade 25 moving blade 26 bearing 27 rotor 28 atmospheric discharge plate 29 exhaust port 30 steam ejector 31 main steam line 32 leaking steam line 33 silencer 34 on-off valve 35 pressure control Valve 36 On-off valve 37 Controller G1-G6 Ground

Claims (4)

[Claims] 1. A steam turbine apparatus comprising: a ground steam condenser for supplying ground steam for sealing a turbine ground portion and draining and collecting leaked steam leaking from the ground portion. A turbine gland leak steam recovery device, wherein an emergency recovery means for actively collecting the leak steam in place of the ground steam condenser in an emergency in the steam leak line is provided. 2. The turbine gland leakage steam recovery device according to claim 1, wherein the emergency recovery means discharges the leaked steam to the atmosphere via a suction means. 3. The turbine gland leakage steam recovery device according to claim 2, wherein said suction means is an ejector for ejecting a pressurized fluid from a nozzle to suck and discharge surrounding leakage steam. 4. A steam ejector driven by main steam from a steam generation source of the steam turbine device, and an on-off valve interposed in a main steam line to the steam ejector. 4. The turbine gland leakage steam recovery device according to claim 2, wherein an on-off valve disposed in a leakage steam line to the ejector is opened when the external power supply is lost.