JP3524939B2 - Exhaust-reburn combined cycle power plant - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention introduces gas turbine exhaust gas into a boiler of a steam turbine plant,
The present invention relates to an exhaust gas re-combustion combined cycle power plant in which exhaust gas of a steam boiler is supplied as a heating medium to an exhaust gas cooler connected in parallel with a feed water heater, and particularly to a water filling system of an exhaust gas cooler system.

[0002]

2. Description of the Related Art FIG. 3 is a schematic system diagram of an exhaust gas re-combustion combined cycle power plant in which the above gas turbine and steam turbine plant are combined, in which high-pressure, high-temperature steam generated in a boiler 1 is a main steam pipe 2 Is introduced into the high pressure steam turbine 3 via the intermediate pressure steam turbine 4 and the low pressure steam turbine 5.
Were introduced to each of them, where work was carried out, and the generator 6
Power is obtained by.

The steam that has worked in the low-pressure steam turbine is condensed in the condenser 7 to become condensate, and the condensate pump 8 condensate demineralizer 9, condensate booster pump 10, gland steam condenser 11 and Degasser 13 through low-pressure feed water heater 12
Sent to. The feed water degassed by the steam deaerator 13 is pressurized by the water feed pump 14 and is returned to the boiler 1 via the high pressure feed water heater 15.

On the other hand, the exhaust gas from the gas turbine equipment is introduced into the boiler 1. That is, the gas turbine equipment includes a compressor 16, a gas turbine 17, and a combustor 18.
And a generator 19 that is rotationally driven by the gas turbine 17, and the exhaust gas from the gas turbine 17 is introduced into the boiler 1 and unburned oxygen is used for combustion in the boiler 1.

Exhaust heat of the boiler exhaust gas after combustion in the boiler 1 is recovered by an air preheater (not shown) into combustion air and used for heating high-pressure feed water and low-pressure feed water. That is, a high-pressure exhaust gas cooler 20 is provided in parallel with the high-pressure feed water heater 15, and a low-pressure exhaust gas cooler 21 is provided in parallel with the low-pressure feed water heater 12 from the air preheater that preheats the combustion air. The exhaust gas is sequentially introduced into the high-pressure exhaust gas cooler 20 and the low-pressure exhaust gas cooler 21, where heat is exchanged with the high-pressure feed water and the low-pressure feed water to recover heat. Then, the heat-exchanged boiler exhaust gas is attracted by an induction ventilator (not shown) installed in the vicinity of the flue inlet, and is discharged to the atmosphere from the chimney 22 through the flue.

[0006]

By the way, the exhaust gas re-combustion combined cycle power plant is intended to perform a highly efficient operation by a combined operation of a gas turbine and a steam turbine. The waste heat of the exhaust gas generated in the boiler is recovered as much as possible for the water supply. Further, in the exhaust gas re-combustion combined power generation system, it is possible to operate the gas turbine power generation and the steam turbine power generation individually and in combined operation from high load to low load.

Therefore, in response to such various operations, it is necessary to perform water filling of the exhaust gas cooler system after maintenance and clean up of the system during the independent operation of the steam turbine plant.

However, when the water supply of the exhaust gas cooler is conventionally filled with water and the system is cleaned up, especially in a high-pressure exhaust gas cooler, the supplied water has a high temperature and high pressure, so that it must be supplied. Since it is impossible, the operation of the steam turbine plant must be stopped, and there is a problem that it is difficult to independently operate the gas turbine power generation and the steam turbine power generation, which are advantages of the exhaust gas re-combustion combined power generation system.

In view of the above points, the present invention enables the water supply of the exhaust gas cooler system to be filled with water and the system to be cleaned up even during the independent operation of the steam turbine plant of the exhaust gas re-combustion combined cycle power plant. It is intended to obtain an exhaust gas re-combustion combined power plant that can improve the operability of

[0010]

A first aspect of the present invention introduces exhaust gas from a gas turbine into a boiler of a steam turbine plant, and heats exhaust gas from the steam boiler into an exhaust gas cooler connected in parallel with a feed water heater. In the exhaust gas re-combustion combined cycle power plant, the condensate booster is connected to each water supply system of the high pressure exhaust gas cooler connected in parallel with the high pressure feed water heater and the low pressure exhaust gas cooler connected in parallel with the low pressure feed water heater. The water-filled pipes branched from the discharge side of the pump are connected through water-filled valves, respectively.

According to a second aspect of the invention, in the first aspect of the invention, a relief pipe for discharging the feed water to a condenser or a blow tank is connected to the outlet side of each water supply system of the high pressure exhaust gas cooler and the low pressure exhaust gas cooler. It is characterized by

A third invention is a high-pressure exhaust gas branched from an outlet side of a low-pressure exhaust gas cooler connected in parallel with a low-pressure feed water heater and having a water-filled pipe having a water-filling valve connected in parallel with the high-pressure feed water heater. It is characterized by being connected to the water supply system of the cooler.

Furthermore, a fourth invention is characterized in that, in the above-mentioned third invention, a relief pipe for discharging the water supply to a condenser or a blow tank is connected to the outlet side of the water supply system of the high-pressure exhaust gas cooler. To do.

[0014]

In the first aspect of the present invention, after the maintenance of each exhaust gas cooler system during the independent operation of the turbine plant, the water filling valve is opened to open the water filling pipe through the water filling pipe branched from the discharge side of the condensate booster pump. Part of the water supply is supplied to each exhaust gas cooler, and each exhaust gas cooler is filled with water.

Further, in the second aspect of the invention, the feed water supplied to each exhaust gas cooler through the water filling pipe as described above is discharged to the condenser or blow tank to clean up each exhaust gas cooler system. Done.

According to the third aspect of the invention, the water supplied through the low-pressure exhaust gas cooler is also supplied to the high-pressure exhaust gas cooler via the water filling pipe, so that both exhaust gas coolers can be filled with water.

Further, a fourth aspect of the invention is that the feed water introduced into the high-pressure exhaust gas cooler is discharged to a condenser or a blow tank via a relief pipe, and the feed water flowing in both the exhaust gas coolers is used to feed the two exhaust gas cooler systems. Cleanup is done.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a system diagram showing a schematic configuration of one embodiment of an exhaust gas re-combustion combined cycle power plant of the present invention,
One end of the water supply pipe 23 of the high-pressure exhaust gas cooler 20 is connected to the downstream side of the water supply pump 14 via the stop valve 24, and the other end is connected to the water supply system on the outlet side of the high-pressure water heater 15 via the stop valve 25. ing. Further, one end of the water supply pipe 26 of the low-pressure exhaust gas cooler 21 is connected to the upstream side of a control valve 27 provided at the inlet side of the low-pressure water supply heater 12 via a stop valve 28, and The other end is connected to a water supply system on the outlet side of the low-pressure water supply heater 12 via a control valve 29 and a stop valve 30. These points are the same as those shown in FIG.

A high pressure exhaust gas cooler water filling pipe 31 is branched from the discharge side of the condensate booster pump 10, and this high pressure exhaust gas cooler water filling pipe 31 is connected to the water filling valve 3.
2 to the downstream side of the stop valve 24. In addition, the water supply pipe 23 on the outlet side of the high-pressure exhaust gas cooler 20
Has a blow valve 33 on the upstream side of the stop valve 25.
Alternatively, the escape pipe 34 communicating with a blow tank (not shown)
Are connected.

On the other hand, a water filling valve 35 is connected in parallel with a stop valve 28 provided upstream of the low pressure exhaust gas cooler 21 by a low pressure exhaust gas cooler water filling pipe 36, and water supply at the outlet side of the low pressure exhaust gas cooler 21 is performed. A relief pipe 38 having a probe valve 37 and communicating with the condenser 7 or a blow tank (not shown) is connected to the pipe 26 on the upstream side of the control valve 29.

FIG. 1 shows the turbine plant in an isolated operation, in which the stop valves 24 and 25 on the inlet side and the outlet side of the high-pressure exhaust gas cooler 20 provided in parallel with the high-pressure feed water heater 15 are closed. ing. Then, when water is supplied to the water supply system after the maintenance of the high-pressure exhaust gas cooler 20 is completed, by opening the water filling valve 32, a part of the condensed water discharged from the condensate booster pump 10 has a high pressure. It is supplied to the high-pressure exhaust gas cooler 20 through the exhaust gas cooler water filling pipe 31, and the water supply system is filled with water.

Further, when the blow valve 33 is opened, the feed water flowing from the high pressure exhaust gas cooler water filling pipe 31 is recovered via the high pressure exhaust gas cooler 20 into the condenser 7 or the blow tank, and while the steam turbine plant is operating, It is possible to clean up the water supply system of the high-pressure exhaust gas cooler.

On the other hand, also in the low pressure exhaust gas cooler 21,
When the water filling valve 35 is opened, the low pressure exhaust gas cooler water filling pipe 3
After 6, a part of the water supply flows into the low-pressure exhaust gas cooler 21, and the water supply system is filled with water.

Further, by simultaneously opening the blow valve 37, the feed water flowing into the low pressure exhaust gas cooler 21 through the low pressure exhaust gas cooler water filling pipe 36 is recovered in the condenser 7 or the blow tank, and the low pressure exhaust gas cooler is cooled. It is possible to clean up the water supply system.

FIG. 2 is a view showing another embodiment of the present invention, in which a high-pressure exhaust gas cooler water-filled pipe 40 is branched from the water supply pipe 26 at the outlet side of the low-pressure exhaust gas cooler 21, and the tip of the high-pressure exhaust gas cooler 20. A water filling valve 41 is provided in the high pressure exhaust gas cooler water filling pipe 40 connected to the downstream side of the stop valve 24 on the inlet side. At the outlet side of the high-pressure exhaust gas cooler 20, the stop valve 2 is provided as in the first embodiment.
A relief pipe 34 having a blow valve 33 is connected on the upstream side of 5.

Therefore, when the exhaust gas coolers 20 and 21 are filled with water and cleaned up during the turbine plant alone operation, if the stop valve 28 is opened with the stop valves 24, 25 and 30 closed, Part of the condensate discharged from the booth pump 10 is introduced into the low-pressure exhaust gas cooler 21 via the stop valve 28, and water filling is performed. Therefore, when the water filling valve 41 is opened, the water flowing into the low pressure exhaust gas cooler 21 flows into the high pressure exhaust gas cooler 20 via the high pressure exhaust gas cooler water filling pipe 40, and the water supply system of the high pressure exhaust gas cooler 20 is filled with water.

When the blow valve 33 is opened at that time, the feed water that has passed through the low-pressure exhaust gas cooler 21 and the high-pressure exhaust gas cooler 20 passes through the blow valve 33 and the escape pipe 34, and then the condenser 7
Alternatively, the water is collected in the blow tank and the water supply system of the first and low pressure exhaust gas coolers can be cleaned up.

By the way, since the condensate booster pump 10 is used to fill and clean up the high pressure exhaust gas cooler 20 and the low pressure exhaust gas cooler 21 during the independent operation of the steam turbine plant as described above, the low pressure and high pressure feed water is supplied. In order not to affect the flow rate of water supplied to the heater, it is possible to secure the flow rate for water filling and cleanup by activating the standby unit 43 of the condensate booster pump. Thus, it is possible to perform water filling and cleanup by minimizing the change in the flow rate of the water supply system during the independent operation of the steam turbine plant.

[0029]

Since the present invention is configured as described above,
Despite the high temperature and high pressure of the feed water during the independent operation of the steam turbine plant, the low temperature and low pressure feed water discharged from the condensate booster pump can be supplied to the high pressure and low pressure exhaust gas coolers. The system can be cleaned up. Therefore, the exhaust gas cooler can be filled with water and the system can be cleaned up during the independent operation of the steam turbine plant, the transition to the combined operation can be performed in a short time, and the operability of the plant can be improved. There is an effect that the equipment of can be effectively used.

[Brief description of drawings]

FIG. 1 is a schematic system diagram of an embodiment of an exhaust gas re-combustion combined cycle power plant of the present invention.

FIG. 2 is a schematic system diagram of another embodiment of the present invention.

FIG. 3 is a schematic system diagram of a conventional exhaust gas re-combustion combined cycle power plant.

[Explanation of symbols] 1 boiler 3 High-pressure steam turbine 4 Medium pressure steam turbine 5 Low pressure steam turbine 7 condenser 10 Condensate booster pump 12 Low-pressure water heater 13 deaerator 15 High pressure water heater 17 gas turbine 20 High-pressure exhaust gas cooler 21 Low pressure exhaust gas cooler 24, 25, 28, 30 Stop valve 31,40 High-pressure exhaust gas cooler Water-filled pipe 32,35,41 Water valve 33,37 blow valve

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F01K 23/10 F22D 1/00

Claims (4)

(57) [Claims] 1. An exhaust gas re-combustion type composite system in which exhaust gas of a gas turbine is introduced into a boiler of a steam turbine plant, and exhaust gas from the boiler is supplied as a heating medium to an exhaust gas cooler connected in parallel with a feed water heater. In a power plant, the high pressure exhaust gas cooler connected in parallel with the high pressure feed water heater and the low pressure exhaust gas cooler connected in parallel with the low pressure feed water heater are branched from the discharge side of the condensate booster pump to the water supply system. An exhaust gas re-combustion combined cycle power plant characterized by connecting water-filled pipes each having a valve. 2. A relief pipe for discharging the feed water to a condenser or a blow tank is connected to the outlet side of each water supply system of the high-pressure exhaust gas cooler and the low-pressure exhaust gas cooler, respectively. Exhaust reburn type combined cycle power plant. 3. An exhaust gas re-combustion type composite system in which exhaust gas of a gas turbine is introduced into a boiler of a steam turbine plant, and exhaust gas from the boiler is supplied as a heating medium to an exhaust gas cooler connected in parallel with a feed water heater. In a power plant, a water-filled pipe branched from the outlet side of the low-pressure exhaust gas cooler connected in parallel with the low-pressure feed water heater and having a water filling valve was connected to the water supply system of the high-pressure exhaust gas cooler connected in parallel with the high-pressure feed water heater. An exhaust gas re-combustion combined cycle power plant characterized by the above. 4. An outlet side of a high pressure exhaust gas cooler water supply system,
The exhaust gas re-combustion combined power plant according to claim 3, wherein an escape pipe for discharging the feed water is connected to the condenser or the blow tank.