KR102329750B1 - Combined cycle power generation system using seasonal thermal energy storage - Google Patents

Abstract

The present invention relates to a combined cycle power generation system using seasonal thermal energy storage, and according to one aspect of the present invention, provided is a combined cycle power generation system comprising a gas turbine unit including one or more gas turbines that rotate a turbine using fuel gas generated by burning fuel, and a gas turbine generator connected to the gas turbine to produce electric power; a heat exchanger for lowering the temperature of the outside air when the temperature of the outside air supplied to the gas turbine is above a certain level; and a heat storage tank for storing cold air to supply the cold air to the heat exchanger in order to lower the temperature of the outside air in the heat exchanger. Accordingly, the combined cycle power generation system of the present invention can supply low-temperature air to the gas turbine even when the temperature of the outside air increases.

Description

Combined cycle power generation system using quarterly heat storage {COMBINED CYCLE POWER GENERATION SYSTEM USING SEASONAL THERMAL ENERGY STORAGE}

The present invention relates to a combined cycle power generation system using quarterly heat storage, and is an invention for a combined cycle power generation system using quarterly heat storage that can improve the efficiency of power generation facilities.

Representative examples of generating electricity using fuel include a gas turbine system and a steam turbine system. A gas turbine burns fuel using fuel and air, and drives a turbine using the generated high-temperature and high-pressure combustion gas. A steam turbine uses a steam generator to heat feed water and supplies the generated steam to the turbine to drive it. Electric power is generated through a generator connected to the gas turbine and steam turbine.

Since the development of such gas turbines and steam turbines, efforts to improve energy efficiency have been continued. In particular, the combined cycle power generation system, which produces energy from a gas turbine and uses the heat of the exhaust gas emitted from the gas turbine to heat the feedwater of the steam turbine cycle by using a Heat Recovery Steam Generator (HRSG), is not suitable for using only a steam turbine or a gas turbine. It is a system with significantly improved power generation efficiency.

At this time, in the gas turbine, when the temperature of the air flowing into the air compression unit is high, the specific volume of the air increases and the absolute amount (absolute flow rate) of the air flowing into the combustion chamber of the gas turbine decreases while the energy for compressing the air is excessively consumed. Accordingly, there is a problem in that the efficiency and output of the gas turbine are reduced.

Therefore, in order to solve this problem, conventionally, a method of supplying the cooled air to the gas turbine after lowering the temperature of the outside air by using a cooling system such as an absorption chiller or an electric chiller is used.

At this time, when an absorption chiller is used, a separate heat source (about 100° C. or higher) is required, and there is a problem in that the output of the steam turbine decreases during operation. This is because some of the steam generally used in steam turbines is added and used as a heat source for absorption chillers.

In addition, in the case of using an electric refrigerator, power required to drive the electric refrigerator is consumed, and in particular, since it is necessary to consume power during the peak period when the temperature in summer is high, the amount of electricity used in the power plant of the combined cycle power generation system increases, so that the total power consumption of the power plant is increased. There may be problems that reduce efficiency.

Republic of Korea Patent Registration No. 10-1531931 (2015.06.22.)

Embodiments of the present invention were invented against the background as described above, and an object of the present invention is to provide a combined cycle power generation system using quarterly heat storage capable of supplying low-temperature air to a gas turbine even when the outside temperature rises.

According to an aspect of the present invention, there is provided a gas turbine unit comprising: a gas turbine unit including one or more gas turbines rotating a turbine using fuel gas generated by burning fuel and a gas turbine generator connected to the gas turbine to generate electric power; a heat exchanger for cooling the temperature of the outside air when the temperature of the outside air supplied to the gas turbine is above a certain level; and a heat storage tank for storing the cold air to supply cold air to the heat exchanger in order to cool the temperature of the outside air in the heat exchanger, it is possible to provide a combined cycle power generation system.

It may further include a refrigerator for producing the cold air so that the cold air is stored in the heat storage tank.

The refrigerator may not be driven when the heat storage capacity of the cold air stored in the heat storage tank is equal to or greater than a certain level.

When the temperature of the outside air supplied to the gas turbine is below a certain level, the refrigerator may be driven to store the cold air in the heat storage tank.

The refrigerator may be driven so that, when the heat storage capacity of the cold air stored in the heat storage tank is less than a predetermined temperature, the cold air supplied to the heat exchanger is less than or equal to a predetermined temperature.

It may further include one or more valves disposed between the heat exchanger, the refrigerator, and the heat storage tank, and controlling the movement of water between the heat exchanger, the refrigerator, and the heat storage tank.

One or more of the valves may be configured to use at least one of a temperature of the outside air supplied to the gas turbine, a temperature of the cold air supplied to the heat exchanger, and a temperature of the cold air discharged from the heat storage tank, the heat exchanger, the refrigerator, and the heat storage tank. You can control the movement of water between them.

According to embodiments of the present invention, it is possible to lower the temperature of the air supplied to the gas turbine by using the quarterly heat storage, so that the annual power production can be increased compared to the case of using the conventional absorption chiller or electric chiller.

In addition, it can be operated in a constant output range throughout the year, and in particular, it can be operated so that low power consumption is achieved even during a time when power consumption is peak in summer.

Moreover, since the underground temperature before cold-heat input is low at about 10°C throughout the year, this has the effect of efficiently storing heat due to shortening of the stabilization period of the underground temperature and low heat loss.

1 is a schematic diagram illustrating a combined cycle power generation system according to an embodiment of the present invention.
2 is a view for explaining the configuration of the electric refrigerator of the combined cycle power generation system according to an embodiment of the present invention.
3 is a view for explaining a state in which the configuration of the heat exchanger is added in the combined cycle power generation system according to an embodiment of the present invention.
4 is a view for explaining a state in which the configuration of the quarterly heat storage tank is added in the combined cycle power generation system according to an embodiment of the present invention.
5 is a view for explaining that the combined cycle power generation system according to an embodiment of the present invention is driven at a lower atmospheric temperature than a predetermined temperature.
6 is a view for explaining that the combined cycle power generation system according to an embodiment of the present invention is driven at a higher atmospheric temperature than a predetermined temperature.
7 is a view for explaining that the combined cycle power generation system according to an embodiment of the present invention is driven when the atmospheric temperature higher than a predetermined temperature or the amount of heat storage is insufficient.

Hereinafter, specific embodiments for implementing the present invention will be described in detail with reference to the drawings.

In addition, in the description of the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, when it is mentioned that a component is 'connected', 'supported', 'connected', 'supplied', 'transferred', or 'contacted' to another component, it is directly connected, supported, connected, It should be understood that supply, delivery, and contact may occur, but other components may exist in between.

The terminology used herein is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In addition, in this specification, the expression of the upper side, the lower side, the side, etc. is described with reference to the drawings in the drawings, and it is clarified in advance that if the direction of the object is changed, it may be expressed differently. For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings, and the size of each component does not fully reflect the actual size.

Also, terms including an ordinal number such as 1st, 2nd, etc. may be used to describe various components, but the components are not limited by these terms. These terms are used only for the purpose of distinguishing one component from another.

The meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and other specific characteristic, region, integer, step, operation, element, component, and/or group. It does not exclude the existence or addition of

1 to 4, a combined cycle power generation system 10 according to an embodiment of the present invention will be described. The combined cycle power generation system 10 drives the gas turbine 102 using gas generated when fuel is burned, and steam is generated in the waste heat recovery boiler using the exhaust gas generated by the driving of the gas turbine 102 . It is a system that generates and uses the generated steam to generate electricity as a steam turbine.

The combined cycle power generation system 10 includes a gas turbine unit 100 , a refrigerator 200 , a heat exchanger 300 , a heat storage tank 400 , a steam turbine unit 500 , an HRGS unit and a cooling tower 700 . do.

The gas turbine unit 100 rotates a turbine using fuel gas generated by burning fuel. The gas turbine unit 100 may include one or more gas turbines 102, and the gas turbine 102 includes an air compressor, a turbine, and a combustion chamber. Air compressed in the air compressor is mixed with fuel and combusted in a combustion chamber. . Accordingly, the high-temperature, high-pressure gas is expanded in the combustion chamber, and the turbine is driven by the expanded force. At this time, the energy generated by the driving of the turbine is transmitted to the gas turbine generator 110 through the turbine shaft to rotate the rotor of the gas turbine generator 110 to produce electricity.

The gas turbine 102 may receive fuel, such as natural gas, from a fuel supplier, and may receive external air from an outdoor air supplier. At this time, the outdoor air supplied through the outdoor air may be supplied to the gas turbine 102 after being cooled by the refrigerator 200 . When the temperature of the outside air flowing into the gas turbine 102 is high, the volume of the air increases and the absolute amount (absolute flow rate) of the incoming air decreases, and at the same time, the energy for compressing the air is excessively consumed, so that the efficiency of the gas turbine 102 is increased. and output may be reduced. Therefore, in order to prevent the efficiency and output of the gas turbine 102 from being reduced, the outside air is cooled through the refrigerator 200 and supplied to the gas turbine 102 . At this time, the cooled outdoor air may contain moisture, so that moisture contained in the outdoor air may be removed through the moisture separator.

The high-temperature combustion gas discharged from the gas turbine 102 may be used as a heat source for generating steam supplied to the steam turbine, and the combustion gas may be supplied to the HRSG unit 600 .

The refrigerator 200 is provided to lower the temperature of the outside air supplied to the gas turbine 102 . In this embodiment, the refrigerator 200 may be an electric refrigerator. The refrigerator 200 includes an evaporator 210 , a condenser 220 , an expansion valve 230 , and a compressor 240 .

The evaporator 210 is one of the devices for exchanging heat, and includes a plurality of pipes for heat exchange with the refrigerant, and the refrigerant may circulate through the plurality of pipes. And it has a structure in which air to be cooled is disposed outside the plurality of pipes to be cooled. For example, the temperature of the air at about 32°C may be lowered to about 10°C through the evaporator 210 .

The evaporator 210 as shown in FIG. 2 may be used as a structure for cooling air using water. In this embodiment, the evaporator 210 may be used as a structure for cooling water using water.

In this way, when the evaporator 210 is used as a structure for cooling water, as shown in FIG. 3 , a heat exchanger 300 may be provided. The heat exchanger 300 is provided to reduce the temperature of the outside air supplied to the gas turbine 102 by receiving water having a lowered temperature from the refrigerator 200 .

For example, the heat exchanger 300 is supplied with water at about 7°C and air at about 35°C from the refrigerator 200 . Accordingly, the heat exchanger 300 may supply air at about 35° C. to about 20° C. and supply it to the gas turbine 102 . And as the temperature of the air is lowered, the heat exchanger 300 may discharge water at about 15° C. toward the refrigerator 200 .

In addition, when the heat storage tank 400 is added, as shown in FIG. 4 , the heat storage tank 400 may be disposed through the valve V disposed between the heat exchanger 300 and the refrigerator 200 . In this case, the valve V may be a switching valve. And the heat storage tank 400 may be a quarterly heat storage tank for storing cold air.

The heat storage tank 400 stores cold air therein, and may store cold air using water. This heat storage tank 400 can store the cold air produced through other renewable energy power generation facilities and commercial systems, including solar power generation, and can supplement the power demand through solar power generation in summer or winter when the power demand is high. . In addition, cold air can be produced with the power produced through solar power generation during the season when the power demand is low and stored in the heat storage tank 400 . The cold air stored in the heat storage tank 400 may be used when the temperature of the outside air supplied to the gas turbine 102 in summer is above a certain level.

In addition, the heat storage tank 400 may be installed underground as cold air is stored.

The steam turbine unit 500 receives high-temperature steam from the HRSG unit 600 and blows it to the blades through the nozzle to obtain rotational force, and uses the obtained rotational force to rotate the rotor of the steam turbine generator 510 to produce electricity do.

The steam turbine receives high-temperature, high-pressure steam from the HRSG unit 600 to rotate the blades, and the discharged steam is supplied to the condenser 220 to be condensed into water. And the condensed water may be supplied back to the HRSG unit 600 to be converted into steam. To this end, the condenser 220 may be connected to the cooling tower 700 , and may be supplied with cooling water for vapor condensation, and the cooling water having an increased temperature after heat exchange with the steam may be transferred back to the cooling tower 700 to be cooled.

The HRSG unit 600 may include a superheater, an evaporator, and an economizer. The superheater receives water from the condenser and heats the water supplied by the heat of the combustion gas discharged from the gas turbine 102 . The evaporator generates steam by reheating the water heated in the superheater with the heat discharged from the gas turbine 102 . The economizer is heated to an appropriate temperature with the heat of the combustion gas discharged from the gas turbine 102 to which the steam generated by the evaporator is delivered. At this time, when the amount of water supplied to the HRSG unit 600 is insufficient, the water supplied through the replenisher may be replenished. Steam generated in the HRSG unit 600 may be supplied to the steam turbine unit 500 .

Here, the HRSG unit 600 may include a plurality of superheaters, evaporators, and economizers, respectively. A superheater, an evaporator, and an economizer for producing high-pressure steam may be disposed on the upstream side based on the flow of gas transferred from the gas turbine 102 , and a superheater, an evaporator and economizer for low-pressure steam production on the downstream side. flags may be placed.

Referring to the drawing shown in FIG. 5 , when the temperature of the atmosphere is less than or equal to a predetermined temperature (eg, about 20° C.), in the combined cycle power generation system 10 , the heat exchanger 300 , the refrigerator 200 and the heat storage tank 400 . ) will be described for heat exchange.

In this way, when the ambient temperature is below a predetermined temperature, the temperature of the outside air supplied to the gas turbine 102 may be directly supplied to the gas turbine 102 without having to go through the heat exchanger 300 . This period can be operated during the inter-season or winter season of the year. However, in the case of the winter season, since the power demand is large, the power supplied to the refrigerator 200 can be cut off to reduce the power consumption.

In addition, when the power demand is small at night or the like, the chiller 200 may be driven to store water cooled in the heat storage tank 400 . At this time, even when the refrigerator 200 is driven, since the outside air supplied to the gas turbine 102 does not go through the heat exchanger 300 , the cold air produced in the refrigerator 200 may not go through the heat exchanger 300 . The valve V may be switched so that water moves only between the refrigerator 200 and the heat storage tank 400 so that cold air moves between the refrigerator 200 and the heat storage tank 400 .

Referring to the drawing shown in FIG. 6 , when the temperature of the atmosphere is higher than a predetermined temperature (eg, 20° C.) and the refrigerator 200 is not used, in the combined cycle power generation system 10 , the heat exchanger 300 , the heat exchange in the refrigerator 200 and the heat storage tank 400 will be described.

When the ambient temperature is higher than or equal to a predetermined temperature, since the temperature of the outside air supplied to the gas turbine 102 is high, the air may be supplied to the gas turbine 102 after the temperature is lowered through the heat exchanger 300 . For example, air having an atmospheric temperature of 35° C. may be lowered to about 20° C. through the heat exchanger 300 .

At this time, when using the cold air stored in the heat storage tank 400 without using the refrigerator 200 , the heat exchanger 300 may receive water stored in the heat storage tank 400 to cool the atmosphere. For example, the heat exchanger 300 receives water at about 12° C. from the heat storage tank 400, cools the air at about 35° C. to about 20° C., and discharges the water that has been raised to about 20° C. to the heat storage tank 400 side. .

To this end, the valve V may be switched to move water between the heat exchanger 300 and the heat storage tank 400 without going through the refrigerator 200 .

Here, it is necessary to check the temperature of the inlet of the gas turbine 102 and the temperature of the outlet of the heat storage tank 400, and through this, it is possible to check whether the outside air supplied to the gas turbine 102 is cooled and the amount of heat available in the heat storage tank 400. have. In this case, the outlet temperature of the heat storage tank 400 may be the same as the inlet temperature of the heat exchanger 300 .

Referring to the drawing shown in FIG. 7 , the air temperature is higher than a predetermined temperature (about 20° C.), and the heat storage amount of the cold air stored in the heat storage tank 400 is insufficient, so that the inlet temperature of the gas turbine 102 is a predetermined temperature. may not be cooled down to In this case, in the combined cycle power generation system 10 , the heat exchange in the heat exchanger 300 , the refrigerator 200 and the heat storage tank 400 will be described.

As the ambient temperature is higher than or equal to a predetermined temperature, an attempt is made to lower the temperature of the outside air supplied to the gas turbine 102 by using the cold air stored in the heat storage tank 400, but the heat storage amount of the cold air stored in the heat storage tank 400 is insufficient. can In this case, the refrigerator 200 may be driven to lower the temperature of the water supplied to the heat exchanger 300 to a predetermined temperature or less.

Accordingly, the heat exchanger 300 may receive the water cooled in the refrigerator 200 and the water stored in the heat storage tank 400 together. Accordingly, by cooling the temperature of the atmosphere in the heat exchanger 300 , external air having a low temperature may be supplied to the gas turbine 102 . In addition, water discharged from the heat exchanger 300 may be discharged to the refrigerator 200 and the heat storage tank 400 .

For example, the heat exchanger 300 may receive water having a temperature of about 12° C. as the water supplied from the heat storage tank 400 and the water cooled from the refrigerator 200 are supplied together. Therefore, even if the temperature of the water in the heat storage tank 400 does not fall below a certain level, it can be cooled to about 12° C. by the water cooled through the refrigerator 200 .

To this end, the valve V may be switched so that the water cooled in the refrigerator 200 and the water discharged from the heat storage tank 400 are combined and supplied to the heat exchanger 300 , and also the water discharged from the heat exchanger 300 . It may be switched to be discharged to the refrigerator 200 and the heat storage tank 400 .

Here, it is necessary to check the atmospheric temperature, the temperature of the inlet of the gas turbine 102, and the temperature of the inlet of the heat exchanger 300, and through this, it is possible to check whether the outdoor air supplied to the gas turbine 102 is cooled, and also, The amount of heat available in the heat storage tank 400 may be checked. In this case, the temperature of the inlet of the heat exchanger 300 may be a temperature at which the discharge temperature of the refrigerator 200 and the temperature of the outlet of the heat storage tank 400 achieve thermal equilibrium.

Although the embodiments of the present invention have been described as specific embodiments, these are merely examples, and the present invention is not limited thereto, and should be construed as having the widest scope according to the embodiments disclosed herein. A person skilled in the art may implement a pattern of a shape not indicated by combining/substituting the disclosed embodiments, but this also does not depart from the scope of the present invention. In addition, those skilled in the art can easily change or modify the disclosed embodiments based on the present specification, and it is clear that such changes or modifications also fall within the scope of the present invention.

10: Combined Cycle Power Generation System
100: gas turbine unit 102: gas turbine
110: gas turbine generator
200: freezer
210: evaporator 220: condenser
230: expansion valve 240: compressor
300: heat exchanger 400: heat storage tank
500: steam turbine unit 510: steam turbine generator
600: HRSG unit 700: cooling tower
V: valve

Claims (7)

a gas turbine unit including one or more gas turbines for rotating a turbine using fuel gas generated by burning fuel and a gas turbine generator connected to the gas turbine to generate electric power;
a steam turbine unit that generates electricity by receiving high-pressure steam;
a heat exchanger for cooling the temperature of the outside air when the temperature of the outside air supplied to the gas turbine is above a certain level;
a heat storage tank for storing the cold air to supply the cold air to the heat exchanger to cool the temperature of the outside air in the heat exchanger; and
and a refrigerator that is electrically driven to store the cold air in the heat storage tank to produce the cold air,
The refrigerator is
an evaporator for supplying cooled water so that the temperature of the outside air in the heat exchanger is cooled;
a condenser connected to the evaporator to circulate the refrigerant, and condensing the refrigerant;
an expansion valve disposed between the evaporator and the condenser to expand the refrigerant moving from the condenser to the evaporator;
It is disposed between the evaporator and the condenser, and comprises a compressor for compressing the refrigerant moving to the condenser in the evaporation,
The condenser receives and condenses the steam discharged from the steam turbine unit,
The refrigerator is driven to store the cold air in the heat storage tank when the temperature of the outside air supplied to the gas turbine is below a certain level,
The refrigerator is driven so that when the heat storage capacity of the cold air stored in the heat storage tank is less than a predetermined temperature, the cold air supplied to the heat exchanger is below a predetermined temperature,
combined cycle power generation system. delete The method of claim 1,
The refrigerator is not driven when the heat storage capacity of the cold air stored in the heat storage tank is above a certain level,
combined cycle power generation system. delete delete The method of claim 1,
and one or more valves disposed between the heat exchanger, the refrigerator, and the heat storage tank to control movement of water between the heat exchanger, the refrigerator and the heat storage tank.
combined cycle power generation system. 7. The method of claim 6,
One or more of the valves may be configured to use at least one of a temperature of the outside air supplied to the gas turbine, a temperature of the cold air supplied to the heat exchanger, and a temperature of the cold air discharged from the heat storage tank, the heat exchanger, the refrigerator, and the heat storage tank. controlling the movement of water between
Combined Cycle Power Generation System

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