JPH03115706A - Grand steam condensing device - Google Patents

Abstract

PURPOSE:To raise a condensation temperature, and improve reliability of facility by applying a second grand steam condenser communicating with a grand steam condensor, in a system provided a condensing system with the grand steam condenser for condensing while recovering sealed steam supplied to a steam turbine. CONSTITUTION:In a steam turbine 1, steam having different pressure is leaked from high and low pressure grands 2, 3, and leaking steam 4 of lowest pressure in the respective grands 2, 3 are recovered into a grand steam condenser 5 so as to condense by heat-exchanging with condensation 6 from a condenser 9 or cooled water, and the steam are recovered into the condenser 9. Steam 7 having a slightly higher pressure than atmosphere pressure in the steam leaked from the high pressure grand 2, is supplied to the low pressure grand 3 through an adjustor 8. In this state, a second grand steam condensor 11 is provided in order to lead excess steam 10 which is not applied to the low pressure grand 3 of steam 7, through adjustor 8, so that heat-exchange between the condensor 11 and condensation 6 is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a grand steam condensing device attached to a steam turbine plant or a combined cycle power plant having a steam turbine.

(Conventional technology) A conventional power generation plant configuration will be explained with reference to FIG.

The steam turbine 1 has a high-pressure gland 2 and a low-pressure gland 3, and has a structure in which steam of different pressures leaks from each. Of these, leak steam (hereinafter referred to as SPE) 4 with the lowest pressure in each gland is in the gland steam condenser 5.
is collected and condensed by exchanging heat with condensate 6 or cooling water,
It is collected again in the cycle. Here, among the steam leaking from the high-pressure gland 2, steam (hereinafter referred to as SSH) 7 with a pressure slightly higher than atmospheric pressure is supplied to the low-pressure gland 3, and air enters the low-pressure section of the steam turbine 1, which is under negative pressure. The low pressure gland 3 is sealed to prevent this. The steam recovered from the low-pressure gland 3 to the gland steam condenser 5 is leaked steam supplied from the high-pressure gland 2. Generally, in a plant operating at rated load, the amount of steam supplied from the high pressure gland 2 to the low pressure gland 3 is greater than the amount of steam required to seal the low pressure gland 3, and the amount of steam supplied from the high pressure gland 2 to the low pressure gland 3 is larger than the amount of steam required to seal the low pressure gland 3.
0 is diverted to the condenser 9 by the action of the grand steam regulator 8 when there is no bleed air from the steam turbine 1 connected to it at an appropriate pressure.

(Problems to be Solved by the Invention) As described above, the amount of steam supplied from the high pressure gland 2 to the low pressure gland 3 is greater than the amount of steam required to seal the low pressure gland 3, and the amount of steam equivalent to 5PU10 is It's wasted.

In addition, there are times when it is necessary to use water of low purity as cooling water for the grand steam condenser 5.

In such a case, there is a high possibility that the tubes of the grand steam condenser 5 will become clogged, but a failure of the only grand steam condenser 5 will cause the steam turbine 1 to trip and stop power generation. This often leads to serious situations.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a gland steam condensing device in which even if surplus steam is generated in a part of the steam sealing a low-pressure gland, the surplus steam is guided to a heat exchanger and heat is recovered to a medium on the cycle side. It's about doing.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention collects seal steam supplied to the gland section of the steam turbine into a condensate system of a combined cycle plant or a steam turbine plant having a steam turbine. The apparatus is provided with a first gland steam condenser for condensing water, and is characterized in that a second gland steam condenser connected to the first gland steam condenser is provided.

(Function) If a second grand steam condenser is installed as in the present invention, steam that was conventionally discarded to the condenser can be recovered, and the temperature of the condensate can be prevented from rising. It is possible.

Furthermore, even if one of the first and second grand steam condensers fails, there is no need to operate the other one and stop the steam turbine plant.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG. In the configuration shown in FIG. 1, the same components as those shown in FIG. Furthermore, in the present invention, the grand steam condenser 5 is referred to as a first grand steam condenser.

In Figure 12, 5PUIO is the grand steam regulator 8
is recovered to the second gland steam condenser 11, and the condensate 6
Heat exchange takes place between the As a result, the inlet temperature of the feed water heater 12 also increases and the amount of bleed air 13 decreases. If the amount of extracted air decreases, the amount of steam flowing through the steam turbine 1 will increase, and the generator output will also increase. Although the feed water heater 12 may be a deaerator, this embodiment is effective when the extraction pressure is below atmospheric pressure. (If there is oil with a pressure below atmospheric pressure, the rest of the low-pressure gland supply steam can be connected to this oil.) The invention shown in Figure 1 aims to improve the efficiency of steam turbine plants. However, an embodiment of the invention that combines improvements in reliability will be described with reference to FIG. 2nd @
Components in the structure that are the same as those shown in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted.

In the present invention, during normal operation, the three-way valves 14 and 15 are opened in the direction shown in FIG. 2, and the first and second grand steam condensers 5 and 11 are operated in two-way mode to improve plant efficiency. If the first grand steam condenser 5 becomes inoperable, the three-way valve 14.1.5 is switched and the steam of 5PE4 is recovered to the second grand steam condenser 11.
PUIO flows into the condenser 9 and the steam turbine 1 is operated continuously. The first gland steam condenser 5 has a bypass valve 1
6 is opened, the condenser valve 18 is closed, and the condenser vent valve 19 is closed to cut off condensate, thereby making it possible to carry out repair work during turbine operation. If the second grand steam condenser 11 becomes inoperable, only the three-way valve 15 is switched, and the 5PU10
In this case as well, the bypass valve 17 is opened, the condenser previous valve 20 and the condenser vent valve 21 are closed, and the second grand steam condenser 11 is repaired during turbine operation. is possible. In this embodiment, if one of the gland steam condensers fails, 5 PUIO must be discarded to condenser 9, which reduces plant efficiency, but even if one of the gland steam condensers fails, FIG. 3 shows an example in which the plant efficiency can be maintained at a high level. Components in the configuration shown in FIG. 3 that are the same as those shown in FIG. 2 are given the same reference numerals, and their explanations will be omitted. In this embodiment, both the first and second grand steam condensers S and 11 have a capacity capable of condensing 5PE4 and 5PU1.0, and the second grand steam condenser 1. 1 is out of order, switch the three-way valve 22, open the bypass valve 17, condenser valve 18, and condenser vent valve 19, and open the bypass valve 16,
When the condenser valve 20 and the condenser vent valve 21 are opened, operation is switched to the first grand steam condenser 5. At this time, since the pressures of 5PE4 and 5SH7 are different, the pressures are controlled by the pressure regulating valve 23.

The invention will be explained below by way of specific examples. In a combined cycle plant consisting of a gas turbine, an exhaust heat recovery heat exchanger, and a steam turbine, 720 kg/h of steam is recovered to the ground steam condenser as SPE in a steam turbine cycle with a rating of 110 M1il, and is discarded to the condenser as SPU. Steam is 960 kg/h. This 960k
When the SPU of g/h is exchanged with condensate using the second grand steam condenser 11, the temperature of the condensate increases by 1.7° C., and the amount of oil in the deaerator decreases by 1070 kg/h. This 1.07
The steam at 0 kg/h is expanded in the steam turbine 1 to increase the output to 180 kg/h. This increases the efficiency of the steam turbine plant by 0.516%. In this example, the heat loads, or cooling areas, of the first and second gland steam condensers 5゜11 were different, but it is also possible to make them completely the same to increase compatibility in operation, maintenance, and inspection. can. In this case, the first and second gland steam condensers 5, 11
If these are connected in series, the inlet temperatures of each gland steam condenser will be different and the heat exchangers will not be the same, so it is necessary to connect them in parallel. FIG. 4 shows a condensate system when the first and second grand steam condensers 5.11 are connected in parallel. Components in FIG. 4 that are the same as those in FIG. 3 are given the same reference numerals, and their explanations will be omitted. When they are connected in parallel, there is an advantage that only one bypass valve can be used.

〔Effect of the invention〕

As described above, according to the present invention, conventionally, during normal operation,
By recovering the thermal energy of the steam that was wasted in the condenser into condensate, it is possible to reduce the amount of air extracted from the turbine, and therefore to increase the generator output. In addition, by having two ground steam condensers, 1
Even if one unit fails, the steam turbine plant can continue to operate with the remaining one, contributing to improved plant reliability.

2 and 3 are configuration diagrams showing other embodiments of the present invention, and FIG. 4 is a diagram showing the structure of the vehicle, and FIG. 5.11... Grand steam condenser 8... Grand steam regulator 9... Condenser 14, 15.22... Three-way valve 1.6.1.7... Bypass valve 18, 20... Condenser valve 19, 21... Condenser vent valve 23... Pressure regulating valve

Claims (1)

[Claims] A first system for collecting and condensing seal steam supplied to a gland section of a steam turbine in a condensing system of a combined cycle plant or a steam turbine plant having a steam turbine.
1. A grand steam condensing device characterized in that a second grand steam condenser connected to the first grand steam condenser is provided.