JPH11257021A - Power-generation plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the heat transmission performance of a gas cooler from lowering and to improve the thermal efficiency of a power-generating plant. SOLUTION: This power-generation plant 10 has a steam turbine 16, a condenser 20 that cools the exhaust of the steam turbine for condensation, and a gas cooling turbine generator 18 that is connected with the steam turbine. A gas cooler 34 is provided for cooling the gas supplied to the gas cooling turbine generator 18 with cooling water. This gas cooler 34 uses the condensate of the steam turbine as cooling water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power plant, and more particularly, to a steam turbine, a condenser for cooling and condensing exhaust gas from the steam turbine, and a gas-cooled turbine generator connected to the steam turbine. And a power plant comprising:

[0002]

2. Description of the Related Art A gas-cooled turbine generator used in a power plant is cooled by hydrogen gas. Conventionally, as shown in FIG. 2, hydrogen gas cooled by cooling water in a hydrogen gas cooler 2 is supplied to a gas-cooled turbine generator 1 through a gas supply path 3 to cool the inside of the generator, The heated hydrogen gas returns to the hydrogen gas cooler 2 through the gas return path 4, is cooled by the cooling water, and is again used for cooling the generator. On the other hand, the heated cooling water is cooled by the cooling tower 5. The cooling tower 5 is connected to the hydrogen cooler 2 by a cooling water circulation path 6, and the cooling water is forcibly circulated by a cooling water pump 7 provided in the cooling water circulation path 6. The cooling tower 5 sprays the heated cooling water from the cooling water circulation path 6 from above, and
, The air is sucked, and the air is forced into contact with the cooling water to cool the cooling water. The cooled cooling water is supplied to the hydrogen gas cooler 2 by the cooling water pump 7 and is used for cooling the hydrogen gas.

[0003] However, if the air sucked into the cooling tower 5 contains dust and toxic gas, the circulating cooling water is contaminated and polluted by them, and as a result, the performance of the hydrogen gas cooler 2 is reduced and cooling is performed. The service life of the piping of the tower 5 and the cooling water circulation path 6 is shortened. To solve this,
Contaminated or polluted cooling water is continuously drained and clean water is replenished to dilute the cooling water so that the concentration of impurities is below a certain level. All of the water was drained and replaced with fresh water. However, it has been found that this method requires a great deal of expense and does not actually provide the expected effect. Therefore, conventionally, contamination of the cooling water or the like has been prevented by injecting a chemical into the cooling water and performing water quality control. More specifically, for example, when the cooling water contains an inorganic substance such as calcium carbonate and magnesium carbonate as hard water, or by adding soda water to precipitate,
Inorganic substances were removed by softening with an ion exchange resin.

[0004]

However, as described above, the cooling water of the hydrogen gas cooler 2 has an open cycle in which the cooling tower 5 comes into contact with atmospheric air.
Even if water quality is controlled by injecting chemicals, in reality,
Due to the corrosive environment caused by atmospheric air pollution,
The scale is deposited and deposited in the cooling water circulation path 6, the piping inside the hydrogen gas cooler 2, and the inside of the cooling tower 5, and as a result, problems such as a decrease in the heat transfer performance of the hydrogen gas cooler 2 occur. . SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and prevents a decrease in heat transfer performance of a gas cooler and omits water quality management by injecting a difficult chemical for the gas cooler. The purpose of the present invention is to provide a power plant capable of performing the above.

Further, the present invention provides a power plant in which the heat efficiency of the entire plant is improved by utilizing the calorific value of the cooling gas of the gas-cooled turbine generator to increase the temperature of the condensate of the steam turbine to recover heat. It is intended to be.

[0006]

In order to achieve the above object, the present invention provides a steam turbine, a condenser for cooling and condensing exhaust gas from the steam turbine, and a gas connected to the steam turbine. In a power plant including a cooling turbine generator, a gas cooler for cooling gas supplied to the gas cooling turbine generator using cooling water is provided, and the gas cooler serves as cooling water for the steam turbine. It is characterized by using water. In the present invention thus configured, the gas supplied to the gas-cooled turbine generator by the gas cooler is cooled using cooling water, and the condensate of the steam turbine is used as the cooling water used here. ing. The condensate of the steam turbine has already been controlled for water quality by chemical injection, so that scale does not settle or accumulate on the piping inside the gas cooler, thereby reducing the heat transfer performance of the gas cooler. Reduction is prevented. Also,
Since the steam turbine condensate which has been sufficiently treated with chemicals is used as the cooling water for the gas cooler, the conventional water quality control by chemical injection for the cooling water can be omitted.
Further, since the heat generation of the cooling gas of the gas-cooled turbine generator is used to raise the temperature of the condensate of the steam turbine to recover heat, the thermal efficiency of the entire power generation plant is also improved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power plant according to the present invention will be described below with reference to the accompanying drawings. FIG.
1 is a schematic overall configuration diagram showing one embodiment of a power plant according to the present invention. As shown in FIG. 1, reference numeral 10 denotes an entire power plant. The power plant 10 includes a boiler 12 that heats feed water to produce steam and a boiler 12.
Superheater 14 that is provided in the heater and heats the steam to produce superheated steam.
And the steam turbine 1 which is supplied with the superheated steam and rotates.
6, a hydrogen gas cooling turbine generator 18 directly connected to the steam turbine 16, a condenser 20 for cooling the exhaust gas of the steam turbine 16 to condense water, and a condenser for circulating condensed water (supply water). A water pump 22 and a water supply pump 24, and a water supply heater 26 for heating the water supply are provided.

[0008] Each of these devices except the hydrogen gas cooled turbine generator 16 is connected by a circulation path 28 for circulating superheated steam, steam, and water in a state of feed water (saturated water). Further, the intermediate portion of the steam turbine 16 and the feed water heater 2
Numeral 6 is connected by an intermediate connection path 30 to heat the boiler feed water using steam heat. Circuit 28
Water in the steam turbine is superheated steam in a circulation path 28a connecting the superheater 14 and the steam turbine 16, and the steam turbine 1
In the circulation path 28 b connecting the condenser 6 and the condenser 20, steam is generated, and the circulation path 28 connecting the condenser 20 and the boiler 12 is formed.
In (c), water is supplied (condensed). In the present embodiment, a bypass passage 32 that bypasses the circulation passage 28c is provided in a circulation passage 28c between the condenser 20 and the feed water heater 26, and the hydrogen gas cooler 3 is provided in the bypass passage 32.
4 are provided. The hydrogen gas cooler 34 is connected to the hydrogen gas cooled turbine generator 18 via a gas supply path 36 and a gas return path 38. The hydrogen gas cooler 34
As described above, the hydrogen gas-cooled turbine generator 18 is cooled to cool the heated hydrogen gas and supply the hydrogen gas to the hydrogen gas-cooled turbine generator 18 again. More specifically, the hydrogen gas cooler 34 is a surface heat exchanger provided with a finned tube (not shown), in which cooling water flows through the tube and hydrogen gas passes through the outer surface of the tube. Heat exchange is performed, and hydrogen gas is cooled by cooling water.

In this embodiment, the hydrogen gas cooler 34 is provided in the bypass passage 32 which bypasses the circulation passage 28c between the condenser 20 and the feed water heater 26 as described above. Steam turbine 1 as cooling water for
6 condensate is used. On the other hand, the water supply (condensed water) circulating in the circulation path 28 is a closed cycle,
Water quality control by chemical injection is inherently sufficient. For this reason, condensed water having a closed cycle as described above and whose water quality has been sufficiently controlled by chemical injection can be used as the cooling water for the hydrogen gas cooler 34.
Next, the operation and effect of the above embodiment will be described. The condensate from the condenser 20 flows to the feed water heater 26 via the condensate pump 22, and a predetermined amount of the condensate flows into the bypass 32 and flows through the hydrogen gas cooler 34. In the hydrogen gas cooler 34, the condensate flows in the finned tube, while the hydrogen gas passes through the outer surface of the tube, and heat exchange between the two is performed. That is, the hydrogen gas cooled inside the hydrogen gas-cooled turbine generator 18 and raised in temperature flows into the hydrogen gas cooler 34 through the gas return path 38 and is cooled by heat exchange with condensate as cooling water. Then, it is supplied again to the hydrogen gas cooled turbine generator 18 through the gas supply path 36.

Here, in the conventional apparatus using the cooling tower shown in FIG. 1, the temperature of the cooling water flowing into the hydrogen gas cooler is about 30 ° C. to about 35 ° C. On the other hand, in the present embodiment, The temperature of condensate used as cooling water is about 3
Since the temperature is 0 ° C. to about 45 ° C., condensed water can be used as cooling water. As described above, in the present embodiment, condensed water having a closed cycle and sufficiently controlled water quality by chemical injection is used as the cooling water for the hydrogen gas cooler 34. As a result, according to the present embodiment, since the condensate used as the cooling water is a closed cycle, the hydrogen gas cooling from the corrosive environment due to the contamination of the atmospheric air, in which the conventional technology using the open cycle cooling water has been placed, is used. The vessel 34 can be isolated. Further, the condensate used as the cooling water is sufficiently controlled for water quality by injecting a chemical, and the chemical treatment is sufficiently performed. Therefore, the scale in the piping (including the tube with the fin) in the hydrogen gas cooler 34 is aging. As a result, it is possible to prevent the heat transfer performance of the hydrogen gas cooler 34 from deteriorating due to scale adhesion.

[0011] Further, when cooling water other than condensed water is used for the hydrogen gas cooler, it is necessary to control the quality of the cooling water by injecting the chemical as described above. Since the condensed water that has already been subjected to the chemical treatment is used as the cooling water, it is possible to omit such water quality control by injecting the chemical. Further, when the cooling tower equipment dedicated for cooling the hydrogen gas cooler is used, the cooling tower equipment becomes unnecessary, and the equipment cost can be reduced. Further, according to the present embodiment, in the hydrogen gas cooler 34, the condensate recovers the calorific value of the hydrogen gas and raises the temperature. More specifically, in the hydrogen gas cooler 34, the condensate cools the hydrogen gas so that the condensate temperature becomes, for example, 3%.
The temperature was raised from 3.1 ° C to 36.4 ° C. Therefore, the thermal efficiency of the entire power plant is improved by the amount of the temperature rise (3.3 ° C. temperature rise) of the condensate in the hydrogen gas cooler 34 in this manner.

[0012]

As described above, according to the power plant of the present invention, it is possible to prevent the heat transfer performance of the gas cooler from deteriorating and to omit water quality control by injecting difficult chemicals for the gas cooler. I can do it. Furthermore, according to the present invention,
By utilizing the calorific value of the cooling gas of the gas-cooled turbine generator to increase the temperature of the condensate of the steam turbine to recover heat, the thermal efficiency of the entire power plant can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram showing an embodiment of a power plant according to the present invention.

FIG. 2 is a configuration diagram showing a cooling device of a hydrogen gas cooler of a hydrogen gas cooling turbine generator in a conventional power plant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Power generation plant 12 Boiler 14 Superheater 16 Steam turbine 18 Hydrogen gas cooling turbine generator 20 Condenser 22 Condensate pump 24 Feedwater pump 26 Feedwater heater 28 Circulation path 30 Intermediate part connection path 32 Bypass path 34 Hydrogen gas cooler 36 Gas supply path 38 Gas return path

Claims (1)

[Claims] 1. A power plant comprising a steam turbine, a condenser for cooling and condensing exhaust of the steam turbine, and a gas-cooled turbine generator connected to the steam turbine, wherein the gas-cooled turbine A power plant, comprising: a gas cooler for cooling gas supplied to a generator using cooling water, wherein the gas cooler uses condensate of the steam turbine as the cooling water.