KR101996281B1

KR101996281B1 - Generating Capacity Augmentation System For Power Plant Using Combined Cycle

Info

Publication number: KR101996281B1
Application number: KR1020120158282A
Authority: KR
Inventors: 유창열; 김현진; 최정호; 박대훈
Original assignee: 대우조선해양 주식회사
Priority date: 2012-12-31
Filing date: 2012-12-31
Publication date: 2019-07-04
Also published as: KR20140087708A

Abstract

An output augmentation system of a gas combined power generation plant is disclosed. The present invention relates to an output augmentation system of a gas combined-cycle power plant, comprising: a gas turbine section for generating electricity by burning gas fuel with compressed air to drive the gas turbine; And an exhaust heat recovery unit that generates steam by driving steam generated from the exhaust gas discharged from the gas turbine as a heat source. In the gas turbine unit, the output of the gas turbine is increased by cooling the air with seawater.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a power generation system,

More particularly, the present invention relates to a gas turbine unit that generates electricity by driving a gas turbine, and a steam turbine that drives exhaust gas discharged from the gas turbine unit by a steam generated from a heat source And an output increasing system of a gas turbine combined cycle power plant that can increase the output by supplying air to the compressor of the gas turbine section by cooling the air with seawater.

Methods for converting energy from combustion to electric energy through a prime mover such as a turbine include a power generation method using a boiler and a steam turbine, a power generation method using a gas turbine, and a combined cycle power generation method combining these methods .

The power generation method by the boiler and the steam turbine uses the heavy oil, the crude oil, the residual oil or the coal as the fuel and drives the turbine by the high temperature and the high pressure steam generated in the boiler. However, the thermal efficiency is 38-40% / HHV (HHV: high calorific value).

Also, the gas turbine uses natural gas such as liquefied natural gas, kerosene, light oil or the like as fuel and burns the fuel with compressed air or compressed air as combustion heat and drives the turbine by the generated high temperature and high pressure gas. The power generation efficiency is 20 to 35%, but the exhaust gas of the gas turbine is high at 450 to 700 ° C., so that such heat can be utilized.

In an air-cooled turbine or the like, the temperature can be increased to about 1300 to 1500 ° C, so that the power generation efficiency can be improved and the exhaust gas can be used more effectively.

In a combined cycle power generation system using these, a liquefied natural gas is used as fuel, a fuel is combusted with compressed air, a gas turbine is driven by the high-temperature high-pressure gas, and the exhaust gas is supplied to a waste heat recovery boiler to generate steam And a method of generating electricity by a steam turbine is carried out, and the thermal efficiency is as high as 46 to 47%. Therefore, when new equipment is installed due to aging of power generation facilities or when power generation using existing facilities is enhanced, conversion to a combined cycle power generation having high thermal efficiency is proceeding.

However, in combined-cycle power generation by liquefied natural gas, the cost of storing LNG as a fuel is required and may cause problems in supply.

In Gumi, there is a good track record of using crude oil and residues as fuel for gas turbines in addition to LNG and diesel. However, due to the impurities contained in these products, many problems arise and the maintenance cost is higher than when diesel or LNG is used .

Especially, as the environmental regulation condition is strengthened recently, the construction of a combined-cycle power plant having high performance and reliability with less emission of pollution compared to coal thermal power and nuclear power generation (apparatus) is rapidly increasing.

Such a combined-cycle power plant (device) basically consists of a gas turbine, a heat recovery steam generator, and a steam turbine. In order to increase the efficiency of the system, the combined-cycle power plant generates electricity by rotating the gas turbine with the high-temperature combustion gas generated by burning the fossil fuel, and then the high-temperature combustion gas discharged from the gas turbine Gas) to produce steam from the batch recovery boiler, which in turn produces a secondary power by turning the steam turbine.

The output of a gas turbine typically occupies more than 60% of the output in a combined-cycle power generation system, the output of which is inversely proportional to the temperature of the air entering the compressor. For example, in Korea, the compressor temperature rises due to the influence of high atmospheric temperature during the summer, when supply stability is very important in case of peak load, so that the gas turbine output may not reach the rated output. The characteristics of the gas turbine according to the atmospheric temperature vary depending on the characteristics of the turbine, but usually show a power reduction of 1% at an atmospheric temperature rise of 1 ° C and a similar increase at ambient temperature Energy Engg, J (1999), Vol.8, No. 1, pp.159 ~ 165), which is a study on the performance improvement of hybrid power plant using LNG cold heat. In case of a power plant in the East Coast of Korea, the summer and summer seawater temperatures are 37 ℃ and 26 ℃, respectively. In other words, the difference between the summer air temperature and the seawater temperature is about 9 ° C.

As a method for increasing the output of the system, there is a method of spraying water or steam to lower the temperature of the air, or a method of providing a cooler for cooling the air introduced into the compressor. Conventionally, Which requires separate power.

The present invention relates to a method for cooling air at the inlet of a compressor in a conventional method for cooling air in a compression process and for increasing the output of a gas turbine without a separate power source, It is possible to cool the air using the seawater and supply it to the gas turbine unit, so that there is no separate heat source, and the seawater system installed in the combined power generation plant is utilized for the power use We propose a system that can increase the output of a combined power plant while reducing costs.

According to an aspect of the present invention, there is provided a system for increasing the output of a gas turbine,

A gas turbine section for generating electricity by burning gas fuel with compressed air to drive the gas turbine; And

And an exhaust heat recovery unit configured to exhaust steam discharged from the gas turbine by driving the steam turbine using steam generated from a heat source,

Wherein the gas turbine unit is configured to increase the density by cooling the air with seawater.

The gas turbine section may include a compression cooling section for compressing the air and cooling it with seawater, a combustor for receiving the air from the compression cooling section to combust the gaseous fuel, and a gas turbine power generation section provided at a rear stage of the combustor.

The compressor and cooling unit may include at least one compressor for compressing air, a cooler for cooling the air introduced into the compressor by heat exchange with seawater, and a flow rate control valve for regulating the flow rate of seawater supplied to the cooler.

The compression cooling unit may further include a controller for controlling the opening and closing of the flow rate control valve by measuring the temperature of the air at the cooler outlet.

The exhaust heat recovery unit includes an exhaust heat recovery boiler for generating steam by evaporating water using exhaust gas discharged from the gas turbine as a heat source, a steam turbine generator for generating electricity by driving the steam turbine supplied from the exhaust heat recovery boiler, A condenser for condensing the steam discharged from the steam turbine generator by heat exchange with seawater and a water feed pump for supplying water collected in the condenser to the arrangement recovery boiler, At least a part of the seawater is supplied to the air to cool the air to increase the density of the air.

The array recovery power generation unit may include a seawater pump for introducing seawater introduced into the condenser, a recirculation pipe connected to a front end of the seawater pump at a rear end of the seawater pump, and a recirculation valve provided in the recirculation pipe.

According to another aspect of the present invention, there is provided a method for increasing the output of a gas turbine,

The steam generator generates steam by driving the gas turbine by burning the gaseous fuel with compressed air and generates steam by using the exhaust gas discharged from the gas turbine as a heat source to drive the steam turbine,

Wherein the compressed air for burning the gaseous fuel is cooled by heat exchange with seawater and then compressed and supplied.

The compressed air can be cooled by separating at least a part of the seawater introduced to drive the steam turbine and vibrate the discharged steam.

An output increasing system of a gas combined-cycle power generation plant of the present invention comprises a gas turbine section for generating electricity by driving a gas turbine, and an arrangement recovery power generation section for generating steam by driving the steam turbine with exhaust gas discharged from the gas turbine section as a heat source By increasing the output of the gas turbine by utilizing a part of the cooling seawater supplied to the condenser of the heat recovery power generation section for cooling the air to be introduced into the compressor of the gas turbine section to increase the output of the combined power generation plant .

FIG. 1 schematically shows an output augmentation system of a gas combined-cycle power plant according to an embodiment of the present invention.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings.

As shown in Fig. 1, in the system for increasing the output of the gas turbine, the output increasing system of the gas turbine of the present embodiment is a system for combusting the gaseous fuel with compressed air to drive the gas turbine A gas turbine section 100 and an exhaust heat recovery section 200 for generating electricity by driving a steam turbine with steam generated from a heat source exhausted from the gas turbine section 100. In the gas turbine section 100, The output of the gas turbine can be increased by cooling the air with seawater.

In the combined-cycle power generation plant, the fuel is burned by compressed air to drive the gas turbine to generate electricity. The exhaust gas discharged from the gas turbine is supplied to the array recovery power generation unit 200 and the steam is generated . As in the summer of Korea, the atmospheric temperature introduced into the compressor 112 of the gas turbine section 100 may increase due to geographical factors such as seasonal factors or low latitude regions near the equator. In order to compensate for the increase in the atmospheric temperature, the compressed air is cooled. In this embodiment, a system using seawater for air cooling is proposed.

The gas turbine section 100 includes a compression cooling section 110 for compressing air and cooling it with seawater, a combustor 120 for supplying air from the compression cooling section 110 to burn the gaseous fuel, And a gas turbine power generation unit 130 provided at the rear stage.

The compressor cooling unit 110 includes at least one compressor 112 for compressing air, a cooler 113 for cooling the air introduced into the compressor 112 by heat exchange with seawater, And a flow control valve 111 for controlling the flow rate.

In the case where a plurality of compressors are provided, the cooler 113 may be connected to the compressor at the inlet side of each compressor, Air can be cooled with seawater.

Although the temperature of seawater differs depending on latitude and season, the highest temperature in summer is around 26 ℃ in the eastern coast of Korea and the low temperature in the low latitude region near the equator is relatively low temperature. Is sufficient to cool the air introduced into the compressor 112 of the gas turbine section 100, taking into account the fact that it reaches about 37 DEG C and about 40 DEG C, respectively.

The compression cooling unit 110 may further include a control unit 114 for controlling the opening and closing of the flow rate control valve 111 by measuring the temperature of the air at the cooler outlet. The control unit may be, for example, a Temperature Indication Transmitter (TIT) that measures the temperature of the air cooled by seawater at the downstream of the cooler and sends a signal to the flow control valve 111 to adjust the valve opening rate.

The arrangement recovery power generation unit 200 includes an arrangement recovery boiler 210 for generating steam by evaporating water using exhaust gas discharged from the gas turbine unit 100 as a heat source, A condenser 230 for condensing the steam discharged from the steam turbine generator 220 by exchanging heat with seawater and a condenser 230 for collecting the water collected in the condenser 230 from the heat recovery boiler 210 And at least a portion of the seawater introduced into the condenser 230 from the gas turbine section 100 is supplied to cool the air to increase the output of the gas turbine.

The arrangement recovery power generation unit 200 includes a seawater pump 250 for introducing seawater introduced into the condenser 230, a recirculation pipe 260 connected to the front end of the seawater pump 250 at a rear end of the seawater pump 250, And a recirculation valve 261 provided in the recirculation pipe 260.

1, in the present embodiment, a part of the seawater introduced into the condenser 230 of the array recovery power generator 200 as cooling water is supplied from the rear end of the seawater pump 250 and is used in the cooler, Can be configured. Thereby, there is no need to provide a separate pump for supplying seawater to the cooler, so that an economical and efficient system configuration is possible.

A part of the seawater introduced into the seawater pump 250 is supplied to the cooler through the piping and the seawater is supplied to the cooler 113 from the rear end of the seawater pump 250 through the recirculation pipe 260, It is possible to recycle it by an amount. Accordingly, the seawater can be supplied to the cooler without increasing the capacity of the seawater pump 250 provided for supplying the seawater to the condenser 230, and the flow rate of the seawater to be supplied to the condenser 230 can be secured. It is necessary to lock both the flow control valve 111 and the recirculation valve 261 and to discharge the entire amount of seawater from the seawater pump 250 to the condenser 230, .

The steam generator generates steam by burning the gaseous fuel with the compressed air to drive the gas turbine to generate electricity. The exhaust gas discharged from the gas turbine is used as a heat source to generate steam,

And the compressed air for burning the gaseous fuel is cooled by the heat exchange with seawater and then compressed and supplied.

At least a portion of the seawater introduced to drive the steam turbine and to vent the discharged steam may be separated to cool the compressed air.

As described above, the output increasing system of the gas combined power generation plant of the present embodiment reduces the power consumption cost by supplying the compressed air having the increased density by cooling the air to sea water to the gas turbine unit 100, Can be increased. Particularly, in the case of designing to receive a part of the seawater from the seawater pump 250 that introduces the seawater into the cooling water of the condenser 230 of the array recovery power generator 200, the air can be cooled and supplied effectively without providing a separate pump do.

As described above, the system of the present embodiment can reduce the cost, and economically, can lower the temperature of the air introduced into the compressor of the gas turbine section, thereby increasing the output of the gas turbine, and thus, a combined power generation plant system capable of increasing the power generation amount can be constructed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Accordingly, such modifications or variations are intended to fall within the scope of the appended claims.

100: gas turbine section
110:
111: Flow control valve
112: compressor
113: Cooler
114:
120: Combustor
130: Gas turbine power generation section
200: Array recovery power generation section
210: Sequence recovery boiler
220: Steam turbine generator
230:
240: Feed pump
250: Sea water pump
260: Recirculation piping
261: Recirculation valve

Claims

A system for increasing the output of a combined-cycle power plant,
A gas turbine section for generating electricity by burning gas fuel with compressed air to drive the gas turbine; And
And an exhaust heat recovery unit configured to exhaust steam discharged from the gas turbine by driving the steam turbine using steam generated from a heat source,
The exhaust heat recovery unit includes a condenser for driving the steam turbine and heat-exchanging the steam discharged from the steam turbine by heat exchange with sea water; A seawater pump for introducing seawater introduced into the condenser; A recirculation pipe connected from a rear end of the seawater pump to a front end of the seawater pump; And a recirculation valve provided in the recirculation pipe,
Wherein a pipe for supplying a part of the seawater introduced into the condenser from the rear end of the seawater pump is diverged and the gas turbine part is introduced into the seawater pump to receive a part of seawater introduced into the condenser, And the output of the gas turbine is increased by increasing the density of the air.

The gas turbine engine of claim 1, wherein the gas turbine section
A compression cooling section for compressing the air and cooling it with seawater;
A combustor that receives air from the compression cooling unit and burns the gaseous fuel; And
And a gas turbine generator provided at a rear stage of the combustor.

The refrigeration system according to claim 2, wherein the compression cooling unit
At least one compressor for compressing air;
A cooler for cooling the air introduced into the compressor by heat exchange with seawater; And
And a flow control valve for controlling the flow rate of the seawater supplied to the cooler.

The refrigeration system according to claim 3, wherein the compression cooling unit
And a control unit for controlling the opening and closing of the flow rate control valve by measuring the temperature of the air at the cooler outlet.

2. The apparatus as claimed in claim 1,
An arrangement recovery boiler for generating steam by evaporating water using exhaust gas discharged from the gas turbine as a heat source;
A steam turbine generator for generating steam by driving the steam turbine supplied from the arrangement recovery boiler; And
Further comprising a water supply pump for supplying the water collected in the condenser to the arrangement recovery boiler.

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