JP2691064B2 - Steam turbine power plant - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a steam turbine power generation plant, and more particularly to a steam turbine power generation plant equipped with a steam turbine for driving a feed water pump.

[Prior Art] In a conventional thermal power and nuclear power plant having a main steam turbine for power generation, a condenser for main steam turbine, and a steam turbine for driving a water supply pump, exhaust steam of a steam turbine for driving a water supply pump is As disclosed in Japanese Patent Laid-Open No. 61-250595, it is configured to be guided to a condenser for a main steam turbine using a complicated exhaust pipe and condensed by the condenser. The details will be described with reference to FIGS. 4 to 7. 4th
The drawing is an explanatory view showing a connection state of a water feed pump driving steam turbine and an exhaust pipe whose other end is connected to a main steam turbine condenser, and FIG. 5 is a view taken along the line I-I of FIG. FIG. 6 is a detailed view of a portion A of FIG. 4, and FIG. 7 is a plan view of FIG. In these figures, 22 is a steam turbine for driving a water supply pump, 41 is a turbine casing, 42 is a rectangular pipe, 43 is a pipe with a pressure balancing expansion joint, and 44 is an exhaust pipe connected to a condenser for the main steam turbine. , 45 are a plurality of vertical and horizontal reinforcing ribs, and 46 is a flange for connection. As can be seen from FIGS. 4 and 5, the square pipe 42 connected and fixed to the square opening of the feed-water-pump driving steam turbine 22 has a side wall of a pipe 43 with a pressure balancing expansion joint whose other end has a circular cross section. It is connected and fixed to. At that time, as shown in FIG. 6 and FIG.
42 has many reinforcing ribs inside and outside to maintain rigidity, and pressure balance type expansion joint tube 43 has bellows on both sides of T tube or elbow, and both sides are fixedly connected by tie rods. It has a pressure balanced expansion joint structure. The pressure-balance type expansion joint tube 43 absorbs the thermal expansion of the exhaust pipe, absorbs the axial force and the fluid force applied to the exhaust pipe, and reduces the force applied to the nozzle of the steam turbine for driving the water supply pump. To fulfill.

Further, in case that it is necessary to raise the degree of vacuum in the condenser for the main steam turbine, the exhaust pipe of the steam turbine for driving the feed water pump is separated from the exhaust pipe for the condenser for the main steam turbine. It has a complicated structure such as a bypass pipe to prevent a sudden drop in the degree of vacuum in the condenser for the main steam turbine due to the sudden opening of the butterfly valve.

[Problems to be solved by the invention]

As described above, conventionally, an exhaust pipe having a complicated structure has been used as a means for condensing the exhaust steam of the steam turbine for driving the water supply pump, but this exhaust pipe is a process pipe for a power plant. The large diameter of the condensate next to the circulating water piping that is sent to the boiler or reactor (for example,
1650 mm). Therefore, the layout of the exhaust pipe is uniquely determined due to the space limitation, and the use of the space around the exhaust pipe is also limited. Therefore, the layout plan of the entire building is also restricted, and there is a drawback that it is difficult to reduce the size and rationalize the building.

An object of the present invention is to eliminate the large-diameter and complicated structure of the exhaust pipe for the feed water pump driving steam turbine as described above without deteriorating the performance of the feed water pump driving steam turbine. It is to remove the restriction of.

[Means for solving the problem]

 Each of the above objects can be achieved as follows.

(1) In a steam turbine power plant having a main steam turbine, a condenser for the main steam turbine, and a steam turbine for driving a feed water pump, the steam turbine for driving the feed water pump is provided separately from the condenser for the main steam turbine. Attach a dedicated condenser.

(2) Arrange a pipe for circulating the drain and the non-condensable gas condensed by the dedicated condenser described above to the condenser for the main steam turbine.

(3) Connect the water pipes of the high / low pressure steam stop valve seat drain, casing drain and seal return steam drain attached around the dedicated ascites device to the dedicated condenser described above.

(4) Connect the water supply / drainage ends of the cooling water pipe of the dedicated condenser described above to the condensate pipe of the main steam turbine described above.

(5) As another means in the case of (4), the water supply / drain ends of the cooling water pipes of the above-mentioned dedicated condenser are respectively connected to the cooling water pipes of the above-mentioned condenser for main steam turbine.

[Action]

Since the present invention uses a condenser exclusively for condensing the feed water pump driving steam turbine, it can be arranged at any position near the feed water pump driving steam turbine. In this way, the exhaust steam from this pump drive turbine is drained at an arbitrary position near this turbine by a dedicated condenser, so the amount of drained water is compared to the exhaust steam amount of the steam turbine. Remarkably small amount.

The drain has a pipe for introducing these together with the non-condensable gas discharged at the same time as the steam into the condenser for the main steam turbine. Flow into.

In addition, the high and low pressure steam stop valve seat drains, casing drains and seal return steam drains attached around the dedicated condenser are connected to the dedicated condenser, so these drains are Can flow into a dedicated condenser.

Furthermore, since the water supply and drain ends of the cooling water pipe of the dedicated condenser are connected to the condensate pipe of the main steam turbine, the exhaust heat of the steam discharged from the steam turbine for driving the water supply pump is Is absorbed and used by.

On the other hand, when the water supply and drain ends of the cooling water pipe of the dedicated condenser are connected to the cooling water pipes of the condenser for the main steam turbine, respectively, the exhaust heat of the steam discharged from the steam turbine for driving the water supply pump is It is absorbed and used in the cooling water of the steam turbine ascites device.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

FIG. 1 is a schematic system diagram of a steam turbine apparatus for a BWR1100MW power generation plant to which the present invention is applied, and FIG. 2 is a detailed system diagram around a turbine for driving a feed water pump of FIG. Fig. 3 shows a specific example of the layout of the dedicated condenser.

In FIG. 1, Toku is a reactor vessel, 3 is a high-pressure steam turbine, 5 is a moisture separator, 6A, 6B and 6C are low-pressure steam turbines, 7 is a condenser for a main steam turbine, 8 is a condenser pipe, and 9 is a condenser pipe. Is a condensate first pump, 12 is a condensate second pump, 14 to 17 are feed water heaters, 18 is a feed pump, and 22 is a feed pump driving turbine.

Further, 25 is a dedicated condenser according to the present invention, 26 is a cooling water feed pipe to the dedicated condenser 25, and 27 is a cooling water return pipe.
On the other hand, 28 is a drain pipe for discharging the condensed water from the dedicated condenser 25, and 29 is a vent pipe for discharging the non-condensable gas. In addition, the steam extracted from the middle of the main steam turbine is used as a heat source of the feed water heaters 14 to 17, 20, and 21, and the steam turbines 3, 6A, 6B, 6C and the feed water heaters 14 to 1 required for that are used.
The piping connecting 7, 20 and 21 is omitted because it has no relation to the present invention.

In the power plant of this embodiment, the steam generated in the reactor vessel 1 is sent to the high-pressure steam turbine 3 by the main steam pipe 2 in FIG. The steam discharged from the high-pressure steam turbine 3 is sent to the low-pressure steam turbines 6A, 6B, 6c through the moisture separator 5 by the crossaround pipes 4A, 4B. The steam discharged from the low-pressure steam turbines 6A, 6B, 6C is condensed by the main steam turbine condenser 7 to be condensed water. The condensate passes through the condensate pipe 8, is pressurized by the condensate first pump 9, and is purified by the condensate filtration desalination device 10 and the condensate deionization device 11. Further, the pressure is increased by the condensate second pump 12, and the first-stage low-pressure feed water drain cooler 13, the first-stage low-pressure feed water heater 14, the second-stage low-pressure feed water heater 15, the third-stage low-pressure feed water heater 16 , Is heated by the fourth-stage low-pressure feed water heater 17, boosted by the feed-water pump 18, and is fed by the feed pipe 19 to the first-stage high-pressure feed water heater 20 and the second-stage high-pressure feed water heater 21.
After being heated in, it is returned to the boiler in the reactor vessel 1,
It forms a circulation cycle.

In such a circulation system, the feed water pump driving steam turbine 22 is operated under a plurality of different driving steam conditions.
That is, the low-pressure exhaust steam of the high-pressure steam turbine 3 by the extraction pipe 23 branched from the cross-around pipe 4B during the normal operation, and the auxiliary steam pipe 24 branched from the main steam pipe 2 at the time of starting.
When the high-pressure steam turbine 3 is under low-load operation or over-load operation, the high-pressure steam is operated by using steam obtained by adding high-pressure steam to low-pressure steam.

A dedicated condenser 25 is directly connected to the exhaust end of the steam turbine 22 for driving the water supply pump. For this cooling water, the first
The cooling water feed pipe 26 branching from the condensate pipe 8 upstream of the stage low-pressure feed water heater drain cooler 13 is attached, and the cooling return pipe 27 is located at the downstream of the cooling water feed pipe attachment point. 8 is connected. Further, a drain pipe 28 for discharging the condensed water of the dedicated condenser 25 and a vent pipe 29 for discharging the non-condensable gas are connected to the condenser 7 for the main steam turbine.

Here, the design exhaust vacuum degree of the steam turbine 22 for driving the feed water pump is a vacuum of about 714 mmHg, and the condensate temperature in the condensate pipe 8 upstream of the first stage low pressure feed water heater drain cooler 13 is about 33 ° C.
Since the saturated vapor pressure at that time is about 722.3 mmHg in vacuum, the required vacuum degree of the dedicated condenser 25 can be secured. That is, the steam discharged from the steam turbine 22 for driving the feed water pump is condensed by the heat exchange of the condensed water in the condensate pipe 8 as a cooling source to become condensed water. The diameter of the drain pipe 28 for discharging the condensate can be reduced to about 200 mm, and the diameter of the bend pipe 29 can be reduced to about 100 mm. Further, the capacity of the dedicated condenser 25 is about 20 m ³ , and can be a rectangular parallelepiped having a length of 2 m, a width of 2.5 m, and a height of 4 m, for example.

The details of the vicinity of the steam turbine 22 for driving the water supply pump will be described with reference to FIG. 2. The low-pressure steam stop valve 30 and the low-pressure control valve 31
The seat drain pipes 34A and 34B, the high-pressure steam stop valve 32, and the seat drain pipes 35A and 35B of the high-pressure steam control valve 33 are guided to the dedicated condenser 25. Further, the casing drain pipes (four) 36 and the seal return steam pipes 37 of the steam turbine 22 for driving the water supply pump are also guided to the dedicated condenser 25. That is, by connecting all of the above-mentioned small-diameter pipes that have been conventionally guided to the main steam turbine condenser 7 to the dedicated condenser 25, these pipes are rationalized and simplified.

FIG. 3 shows the arrangement of a steam turbine device for driving a water feed pump according to an embodiment of the present invention. In FIG.
The exhaust port of the steam turbine 22 for driving the water supply pump has a rectangular shape as in the conventional case shown in FIG. 5, and a rectangular parallelepiped dedicated condenser 25 is arranged directly below this exhaust port in a direct-integrated integrated structure. A cooling pipe group (39) and an expansion joint (38) for absorbing vibration are attached. Cooling water feed pipes on both sides of the dedicated condenser 25
26 and water chambers 40A and 40B for connecting the cooling water return pipe 27,
It is connected to the cooling pipe group 39. (The water chambers 40A and 40B can also be housed inside the dedicated condenser 25.) Further, a drain pipe 28 is provided from the lowermost end of the dedicated condenser 25, and a vent pipe 29 is provided from the center of the cooling pipe group 39. It branches and leads to the condenser 7 for the main steam turbine. In the present embodiment, the drain pipe 28 and the vent pipe 29 are connected to the lower shell of the main steam turbine condenser 7, but the diameter of these pipes is about 1/6 of the conventional exhaust pipe diameter.
Since it is miniaturized, it can be connected to the upper shell of the main steam turbine condenser 7 and in any direction. Specifically, the low pressure feed water heater of the first stage to the fourth stage in the past
Since 14 to 17 are built in the upper body of the condenser 7, the exhaust pipe of the feed water pump driving steam turbine 22 can be connected to only the lower body of the condenser 7 for the main steam turbine and a certain surface. There wasn't. Therefore, you can arrange the exhaust pipe,
Alternatively, it is no exaggeration to say that the position at which the feed water pump driving steam turbine 22 is disposed is determined by the position at which the exhaust pipe is connected to the main steam turbine condenser 7.
In the present invention, contrary to the above case, after the rational arrangement of the steam turbine 22 for driving the feed pump is determined, the drain pipe is
28 and the vent pipe 29 can be freely laid out. Furthermore, it is possible to significantly expand the space that can be used for other projects. Further, the sheet drain pipes 34A, 34B, 35A, 35B, the casing drain pipe 36 and the seal return steam pipe 37 shown in FIG. 2 are guided to the dedicated condenser 25 (the casing drain pipe 36 may be an internal pipe. By this, the connection of these pipes to the condenser 7 for the main steam turbine, which has been conventionally performed, is not necessary, and this can also contribute to the expansion of the above-mentioned usable space.

〔The invention's effect〕

According to the present invention described above, the following effects can be obtained.

(1) By installing a dedicated condenser at an arbitrary position near the steam turbine for driving the water supply pump, it is not necessary to install a large-diameter exhaust pipe for the steam turbine for driving the water supply pump, which allows steam turbine power generation. The space requirement of the plant can be reduced.

(2) Since the diameters of the dedicated condenser drain and vent pipes can be made smaller, and by introducing small-diameter pipes such as high / low pressure steam stop valve seat drains to the dedicated condenser, the degree of freedom in building layout is increased. It is possible to improve, rational arrangement of the whole building and downsizing of the building. (3) By adopting the condensate of the main steam turbine as the cooling water for the dedicated condenser, it becomes possible to recover the exhaust heat from the steam turbine for driving the feed water pump, and improve the thermal efficiency of the entire power plant. it can.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram of a BWR power generation plant to which an embodiment of the present invention is applied, FIG. 2 is a detailed system diagram around a steam turbine for driving a feed water pump of FIG. 1, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a vertical cross-sectional view of a connection portion of a conventional exhaust pipe showing the arrangement of a steam turbine for driving a feed water pump and a condenser for a main steam turbine, FIG. Of I
-I line arrow view, FIG. 6 is the A section enlarged view of FIG. 4, FIG. 7 is a top view of FIG. 3 ... High-pressure steam turbine, 6A, 6B, 6C ... Low-pressure steam turbine, 7 ... Condenser for main steam turbine, 8 ... Condenser pipe,
22 …… Steam turbine for water supply pump drive, 25 …… Dedicated condenser, 26 …… Cooling water feed pipe, 27 …… Cooling water return pipe, 28 ……
Drain pipe, 29 …… Vent pipe, 34A, 34B, 35A, 35B …… Seat drain pipe, 36 …… Casing drain pipe, 37 …… Seal return steam pipe.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Isao Tanaka 3-1-1, Saiwaicho, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor Hiroshi Kitakata 3-1-1, Saiwaicho, Hitachi, Ibaraki No. 1 Hitachi, Ltd., Hitachi Plant (56) References JP-A-49-38116 (JP, A)

Claims (5)

(57) [Claims] 1. A steam turbine power plant having a main steam turbine, a condenser for the main steam turbine, and a steam turbine for driving a water supply pump, wherein the steam turbine for driving the water supply pump has a condenser for the main steam turbine. A steam turbine power plant characterized in that a separate dedicated condenser is attached. 2. The pipe according to claim 1, wherein a pipe is provided for circulating the drain and the non-condensable gas condensed from the dedicated condenser to the condenser for the main steam turbine. A characteristic steam turbine power plant. 3. The high / low pressure steam stop valve seat drain, casing drain and seal return steam drain attached to the dedicated condenser around the dedicated condenser according to claim 1 or 2. A steam turbine power plant characterized in that each of the water supply pipes is connected. 4. The steam turbine power plant according to claim 1, wherein the water supply / drainage ends of the cooling water pipe of the dedicated condenser are connected to the condensate pipe of the main steam turbine, respectively. 5. The steam according to claim 1, wherein the water supply / drain ends of the cooling water pipe of the dedicated condenser are connected to the cooling water pipe of the condenser for the main steam turbine, respectively. Turbine power plant.