JPS6010162B2 - combined plant - Google Patents

Description

Detailed Description of the Invention The present invention combines a gas turbine, a scarlet heat recovery boiler that uses gas turbine exhaust gas as a heat source, and a steam turbine that uses steam generated in this boiler as a driving medium and is equipped with a deaerator. This is related to the combined prasotho.

Traditionally, this type of combined plant 'was equipped with a scarlet heat recovery boiler to obtain steam to drive a steam turbine using the exhaust gas of the gas turbine. Trying to recover heat.

For example, in the invention described in Tokukan Sho 49-127148, a water supply line from a deaerator is connected to a low-pressure economizer of a boiler, and a water supply line from a low-pressure heater is connected to an intermediate-pressure section of a steam turbine. Thermal efficiency has been improved by connecting the low-pressure steam line that leads the heated steam to the deaerator. However, in this method, although it is possible to increase the amount of heat recovered in the scarlet heat recovery boiler, the structure becomes complicated, which is disadvantageous from an economical and technical point of view.

An object of the present invention is to provide a combined plant consisting of a combination of a gas turbine and a steam turbine, which has a simple structure and can improve thermal efficiency. A heat exchanger, a pipeline that supplies the water extracted from between the poller water pump and the booster pump to the heat exchanger, and hot water heated by the gas turbine exhaust gas in the heat exchanger that supplies it to the deaerator. It is characterized by the provision of a conduit.

An embodiment of the present invention will be described below with reference to FIG.

A gas turbine power generation device 1 includes a compressor 2 and a gas turbine 3.
, a generator 4 and a combustor 5, the air pressurized by the compressor 2 is sent to the combustor 5, where fuel is blown into the pressurized air and combusted, and the generated gas is fed to the gas turbine 3. 7 is a scarlet heat recovery boiler connected to the gas turbine 3 through a duct 6. In this boiler, the exhaust gas discharged from the gas turbine 3 recovers its retained heat. After being collected, it is released into the atmosphere from the chimney 13.

A superheater 8, an evaporator 9 having a high-pressure boiler 9a, a high-pressure heat exchanger 10, and a low-pressure heat exchanger 11 are sequentially arranged in the scarlet heat recovery boiler 7 from the exhaust gas upstream side of the gas turbine 3, and the superheater 8. Evaporator 9 and high pressure heat exchanger 10'
Well, they are set up consecutively.

The inlet side and outlet side of the low-pressure heat exchanger 11 are connected to the outlet side of a water supply pump booster pump 22 and a deaerator 21, respectively, which will be described later. 14 is the steam turbine 1
5 and ``The generator 16 driven by this steam turbine 15 and the high pressure steam from the superheater 8 are supplied to the steam turbine 1.
5, which is installed in the high pressure steam pipe 17 and connected to the steam turbine 1.
a steam valve 18 for controlling the amount of steam flowing into the steam valve 5;
It consists of a condenser 19 that condenses the steam that has worked in the bin 15.

20 is a condensate pump, 21 is a deaerator, 22 is a booster pump for the water supply pump, 23 is a water supply pump, and these devices 20 to 23 are the condenser 19 and the high pressure heat exchanger of the scarlet heat recovery boiler 7 It is provided in the water supply piping 24 that connects.

Further, the deaerator 21 is connected to the intermediate stage of the steam turbine 15 via a bleed pipe 25 and to the outlet side of the low pressure heat exchanger 11 of the noble E heat recovery boiler 7 via a high temperature water pipe 27 having a control valve 28, respectively. has been done. Since this embodiment is configured as described above, the structure can be simplified, and the high temperature water recovered by the low pressure heat exchanger 11 provided in the scarlet heat recovery boiler 7 is used as a heat source for the deaerator 21. By this,
It is possible to reduce the amount of evaporation of the citrus gas that is evaporated from the steam turbine 15 and introduced into the two deaerators.

Therefore, the output of the steam turbine 5 can be increased by the amount of the decrease. Furthermore, since the low-pressure heat exchanger 11 of the scarlet heat recovery boiler 7 is installed at the rear end of the exhaust gas flow path of the gas turbine 3, the amount of steam generated by the superheater 8 is not affected by the provision of the low-pressure heat exchanger 1.

Therefore, the amount of heat recovery can be increased by the increase in the amount of heat of the high-temperature water extracted from the low-pressure heat exchanger 11 to the outside of the 9E heat recovery boiler 7, so that the exhaust gas released from the 9E heat recovery boiler 7 into the atmosphere Temperature can be lowered.
As described above, the output of the steam turbine 16 can be increased by increasing the amount of heat recovered in the low-pressure heat exchanger 11.

For example, in a combined cycle power plant with a total output of 265,000 kW that combines three gas turbine generators with an output of 61,000 kW and one steam turbine generator with an output of 8,200 kW, the same number of exhaust heat recovery boilers as the gas turbine generators are installed. ~9E Booster pump outlet water for the boiler feed water pump was supplied to the low pressure heat exchanger installed in the heat recovery boiler at 680 n'hr per exhaust heat recovery boiler,
The output of the steam turbine can be increased by 1750KW. In this case, the amount of water supplied by the booster pump for the boiler water supply pump increases by the amount of circulation to the low-pressure heat exchanger, resulting in a loss of 9 trays W corresponding to the increase in pump shaft power.

If this loss is subtracted from the steam turbine output increase of 1,750 kW, the power transmission end output can be increased by 1,660 kW. This increase in output will result in a relative increase in combined cycle power plant and transmitter efficiency of 0.6%. Also, when comparing the above low-pressure heat exchanger circulation method and the conventional method of extracting a portion of the high-temperature water at the outlet of the high-pressure heat exchanger and recovering heat to the deaerator, if the amount of heat recovered to the deaerator is the same, , the output of the steam turbine similarly increases by 175 W, but since the feed water is circulated by a high-pressure boiler feed water pump, the increase in shaft power of the boiler feed water pump increases by 50 W.
The total power transmission output will increase by 1250KW.

Therefore, the output at the sending end is 4
Generates 10KW more. In this implementation, when the deaerator is installed directly at a higher level than the required pushing pressure of the water pump, a booster pump for the water pump is not provided.

In this case, it is possible to extract low-pressure feed water from the middle stage of the boiler feed pump and send it to the low-pressure heat exchanger.
You can get the same effect as in this example. In this way, with a simple structure such as providing a separate system for supplying hot water from the outlet side of the booster pump for the water supply pump to the deaerator in the Enoki E heat recovery boiler, separate from the system for the steam turbine, it was possible to recover sufficient heat with the 9E heat recovery boiler. At this time, the feed water sent to the low-pressure heat exchanger from the outlet side of the booster pump for the water pump is low temperature, and hot water rather than steam can be sent to the sharp air tank, so it can be used for steam turbines. The remaining heat from the exhaust gas is sufficient.As explained above, according to the present invention, the amount of heat recovered by the scarlet heat recovery boiler can be increased with a simple structure. By being able to reduce the amount of steam flowing into the steam turbine, the output of the steam turbine can be increased, and the thermal efficiency of the combined plant can be improved.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the combined plant of the present invention. 3...Gas turbine, 7...9E heat recovery boiler, 1
1...Low pressure heat exchanger, 15...Steam turbine, 21
...Deaerator, 22...Booster pump, 23...Boiler water pump. younger brother's figure

Claims (1)

[Claims] 1. A gas turbine, an exhaust heat recovery boiler including a economizer, an evaporator, and a superheater placed in the exhaust gas flow path to generate steam using the heat contained in the gas turbine exhaust gas, and a A steam turbine as driving steam, a condenser for condensing the exhaust gas of the steam turbine, a deaerator for deaerating the condenser, a booster pump and water supply for supplying the deaerated condensate to the boiler. In a plant equipped with a pump, a low-pressure heat exchanger provided in the exhaust heat recovery boiler on the most downstream side with respect to the exhaust gas flow, and a pipe that supplies feed water extracted from between a boiler feed water pump and a booster pump to the heat exchanger. and a pipe line for supplying hot water heated by the exhaust gas of the gas turbine in the heat exchanger to the deaerator.