JP2782986B2 - Combined cycle equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined cycle facility.

[0002]

2. Description of the Related Art In recent years, with the aim of increasing the efficiency of thermal power generation,
Research and development of combined cycle equipment such as combined power generation equipment using a pressurized fluidized bed boiler has been conducted.

[0003] An example of a pressurized fluidized bed combined cycle power plant will be described below with reference to FIG.

A pressurized fluidized-bed boiler 18 in a combined pressurized fluidized-bed power plant includes a cell 3 containing an evaporator 5, a superheater 1 and a reheater 2, and a pressure vessel 7 containing the cell 3. A predetermined amount of bed material 4 is loaded in the cell 3.

[0005] The upstream end of the superheater 1 in the steam flow direction is connected to the feed pump 9 via a water supply line 19 via the evaporator 5, and the downstream end is connected to the steam of the high-pressure turbine 11 of the steam turbine facility 10 via a line 20. An upstream end of the reheater 2 in the steam flow direction is connected to a steam outlet of the high-pressure turbine 11 of the steam turbine facility 10 via a pipe 21, and a downstream end is connected to a steam outlet of the steam turbine facility 10 via a pipe 22. Medium and low pressure turbine 1
2 and a steam outlet of the medium-to-low pressure turbine 12 is connected to the feed pump 9 via a condenser 13 through a conduit 23.

A low-pressure water heater 29 and a deaerator 8 are provided in the water supply line 19 between the water supply pump 9 and the condenser 13, and are provided in the water supply line 19 downstream of the water supply pump 9. Includes a high-pressure water heater 30 and a gas turbine 2 described later.
An exhaust gas cooler 32 for cooling exhaust gas flowing through the pipe line 31 on the downstream side is provided.

In the pressurized fluidized bed combined cycle power generation system described above, compressed air obtained by compressing the atmosphere 15 by the compressor 14 is supplied to the pressure vessel 7 from the compressed air supply line 16, and the fluidized bed 17 And a fluidized bed 1
The fuel (coal) 6 is supplied to 7 and burned in the fluidized bed 17.

When the fuel 6 burns, its thermal energy is transmitted to the bed material 4 in a fluidized state, and the bed material 4 comes into contact with the evaporator 5, the superheater 1 and the reheater 2, whereby the heat energy is transferred. Energy is transmitted to the evaporator 5, the superheater 1, and the reheater 2.

The boiler water that has exited the condenser 13 is heated by the low-pressure water heater 29, passes through the deaerator 8 and is supplied to the evaporator 5 by the water pump 9, and is heated by the high-pressure water heater 30 while being supplied to the evaporator 5. After heat exchange with the exhaust gas to be described later in the exhaust gas cooler 32, the gas flows into the evaporator 5 and is vaporized by the thermal energy. The vapor is superheated by the superheater 1, and the superheated steam is supplied to the high-pressure turbine 11 of the steam turbine facility 10. The high pressure turbine 11 is driven by the inflow.

The steam after driving the high-pressure turbine 11 is:
The steam which flows into the reheater 2 and is reheated by the reheater 2 flows into the medium / low pressure turbine 12 and
The steam after driving the turbine 2 and further driving the medium-to-low pressure turbine 12 is returned to the boiler water by the condenser 13 and is again supplied to the evaporator 5 by the feed water pump 9.

In this manner, the steam turbine facility 10 is driven by the steam, and the power is generated by the steam turbine generator 24 connected to the steam turbine facility 10.

On the other hand, the exhaust gas of the fuel 6 burned in the cell 3 is supplied to a gas turbine 26 by a pipe 25, flows through a pipe 31 and is cooled by an exhaust gas cooler 32, and is discharged from a chimney 28. Electric power is generated by a gas turbine generator 27 connected to a turbine 26, and
At the same time, the compressor 1 is
4 is driven.

As shown in FIG. 3, in addition to the type in which the exhaust gas cooler 32 is provided in series with the high-pressure water heater 30,
Conventionally, as shown in FIG. 5, a bypass line 33 branches from a water supply line 19 between the water supply pump 9 and the high-pressure water heater 30 and is connected to the water supply line 19 downstream of the high-pressure water heater 30. There is also a type in which an exhaust gas cooler 34 is provided.

[0014]

In the case of the in-line type shown in FIG. 3, since the boiler water at the full flow rate heated by the high-pressure water heater 30 is supplied to the exhaust gas cooler 32, as shown in FIG. The temperature of the exhaust gas at the outlet of the exhaust gas cooler 32 must be equal to or higher than the temperature of the feed water at the outlet of the high-pressure water heater 30, so that the amount of temperature decrease of the exhaust gas in the exhaust gas cooler 32 becomes small, It becomes smaller and exits the exhaust gas cooler 32 and
The temperature of the boiler water supplied to the furnace was low, and the thermal efficiency was poor.

In the case of the parallel type shown in FIG.
Since a part of the boiler water before being heated by the high-pressure water heater 30 branches to the bypass pipe 33 and is supplied to the exhaust gas cooler 34, and the remaining boiler water is supplied to the high-pressure water heater 30, it is shown in FIG. Exhaust gas cooler 3
4, the amount of heat received from the exhaust gas of the boiler water increases in proportion to the temperature difference, and the boiler exits the exhaust gas cooler 34 and is heated by the high-pressure water heater 30. Merge with water and evaporator 5
The temperature of the boiler water supplied to the furnace is higher than that of the in-line type, and the heat efficiency is good, but the heat transfer area proportional to the amount of heat received has to be increased, leading to an increase in cost. In FIG. 6, the temperature of the boiler water after being heated by the high-pressure water heater 30 is lower than the temperature of the boiler water after leaving the exhaust gas cooler 34, and when the two merge again, the temperature of the boiler water is reduced. Indicates a case where the required amount decreases.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a combined cycle facility having good thermal efficiency, a small heat transfer area of an exhaust gas cooler, and cost reduction.

[0017]

SUMMARY OF THE INVENTION The present invention comprises a gas turbine and steam turbine equipment, and a low-pressure water heater, a water supply pump, and a high-pressure water heater are provided in a water supply line downstream of a condenser of the steam turbine equipment. In a combined cycle facility in which a water supply heater and a water supply heater are sequentially provided from an upstream side, in a bypass line that branches off from a water supply line between the water supply pump and the high-pressure water supply heater and is connected to a water supply line on the downstream side of the high-pressure water supply heater. A first exhaust gas cooler for cooling the exhaust gas of the gas turbine is provided, and the exhaust gas on the downstream side of the gas turbine is provided in the middle of the water supply line downstream from a connection portion of the bypass line to the water supply line. A second exhaust gas cooler for cooling is provided.

[0018]

Therefore, heat exchange between boiler water and exhaust gas is performed by the first exhaust gas cooler provided in parallel with the high-pressure water heater and the second exhaust gas cooler provided in series with the high-pressure water heater. The temperature of the boiler water that has passed through the second exhaust gas cooler does not decrease, the thermal efficiency is good, and the respective heat transfer areas of the first exhaust gas cooler and the second exhaust gas cooler can each be reduced, so that the cost can be reduced.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, the portions denoted by the same reference numerals as those in FIGS. 3 and 5 represent the same components, and the basic configuration is the same as that shown in FIGS. However, as shown in FIG. 1, the present embodiment is characterized in that it branches off from the water supply line 19 between the water supply pump 9 and the high-pressure water heater 30 and is located downstream of the high-pressure water heater 30. A first exhaust gas cooler 35 for cooling exhaust gas on the downstream side of the gas turbine 26 is provided in parallel with the high-pressure water heater 30 in the middle of the bypass line 33 connected to the water supply line 19. A second exhaust gas cooler 36 for cooling exhaust gas on the downstream side of the gas turbine 26 is provided in series with the high-pressure water heater 30 in the middle of the water supply line 19 on the downstream side of the connection portion to the water supply line 19. is there.

In this embodiment, the high-pressure water heater 30
A part of the boiler water before being heated by the air is branched to the bypass pipe 33 and supplied to the first exhaust gas cooler 35 to be supplied to the pipe 31.
While removing heat from the exhaust gas flowing through the heater, the remaining boiler water is supplied to the high-pressure water heater 30 and heated, and the boiler water exiting the first exhaust gas cooler 35 is discharged from the high-pressure water heater 30.
And the boiler water after being heated again, the combined boiler water is supplied to the second exhaust gas cooler 36 to remove heat from the exhaust gas, and the boiler water passing through the second exhaust gas cooler 36 is transferred to the evaporator 5. Supplied.

As a result, as shown in FIG. 2, the temperature of the boiler water supplied to the evaporator 5 is higher than that of the in-line type shown in FIG. Each heat transfer area can be reduced, and cost can be reduced.

The combined cycle equipment of the present invention is not limited to the above-described embodiment, and is not limited to the pressurized fluidized bed combined cycle power equipment, but is also applicable to combined cycle equipment such as an exhaust gas reburning combined cycle. Needless to say, various changes can be made without departing from the spirit of the present invention.

[0024]

As described above, according to the combined cycle equipment of the present invention, it is possible to obtain an excellent effect that the thermal efficiency is good, the heat transfer area of the exhaust gas cooler is reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of one embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between exhaust gas temperature and feedwater temperature in one embodiment of the present invention.

FIG. 3 is a conceptual diagram of a conventional example.

FIG. 4 is a diagram showing a relationship between exhaust gas temperature and feedwater temperature in the conventional example of FIG. 3;

FIG. 5 is a conceptual diagram of another conventional example.

6 is a diagram showing the relationship between the exhaust gas temperature and the feedwater temperature in the conventional example of FIG.

[Explanation of symbols]

 Reference Signs List 9 water supply pump 10 steam turbine equipment 13 condenser 19 water supply line 24 steam turbine generator 26 gas turbine 27 gas turbine generator 29 low pressure water heater 30 high pressure water heater 33 bypass line 35 first exhaust gas cooler 36 second exhaust gas cooler

Claims (1)

(57) [Claims] 1. A steam turbine system comprising a gas turbine, a low-pressure water heater, a water supply pump, and a high-pressure water heater in the middle of a water supply pipe downstream of a condenser of the steam turbine equipment. In the combined cycle equipment that is provided, the exhaust gas of the gas turbine is discharged from a water supply line between the water supply pump and the high-pressure water heater, in the middle of a bypass line connected to a water supply line downstream of the high-pressure water heater. A second exhaust gas cooler for cooling the exhaust gas downstream of the gas turbine in the middle of a water supply line downstream from a connection portion of the bypass line to the water supply line while providing a first exhaust gas cooler for cooling. Combined cycle equipment characterized by the following.