KR101303811B1 - Combined cycle power plant utilizing waste heat - Google Patents

Abstract

PURPOSE: A combined cycle thermal power generation system utilizing waste heat is provided to increase generating efficiency since a steam turbine is operated by an ammonia refrigerant which uses the exit latent heat in the steam turbine. CONSTITUTION: A combined cycle thermal power generation system utilizing waste heat includes a heat exchanging unit (110), a vacuum pump (120), a booster pump (130), a second generator (150), a second steam turbine (140), and a condenser (160). The heat exchanging unit is prepared in between a steam turbine (30) and a steam condenser (40) to circulate a part of a saturated refrigerant which is delivered to the steam condenser. The vacuum pump is equipped on a first pipe (L1) which is provided in between the steam turbine and the heat exchanging unit to flow the saturated refrigerant of the outlet side of the steam turbine. The booster pump is equipped on a second pipe (L2) which is prepared between the heat exchanging unit and the condenser so that the saturated refrigerant, which exchanges heat in the heat exchanging unit, streams down to the condenser. The second steam turbine is driven by ammonia vapor which is generated in the heat exchanging unit. The second steam turbine drives the second power generator for power generation. The condenser enables the ammonia refrigerant to circulate in the heat exchanging unit by condensing the ammonia vapor which is used in the second turbine. [Reference numerals] (120) Vacuum pump; (130) Booster pump; (160) Condenser; (170) Pump control module; (AA) 35-36°C ammonia water (liquid); (BB) Local heating source; (CC) Natural gas; (DD) Compressed air

Description

Combined cycle power plant utilizing waste heat

The present invention relates to a combined cycle power generation system that can improve the power generation efficiency, and more particularly, to a combined cycle power generation system that can increase the power generation efficiency by recycling the waste heat generated from the latent heat of the steam turbine or the condenser.

Combined cycle power generation is the second generation of the energy produced from the primary power generation through fuel, and the primary gas turbine is generated by using fuel such as natural gas or diesel fuel, and the exhaust gas heat from the gas turbine is recovered again. The steam is passed through the boiler to produce steam, and the steam turbine is secondarily generated.

Since the combined-cycle power develops twice, the thermal efficiency is higher than the existing thermal power, the pollution is less and the time to restart after the shutdown is short. In the construction period, it is only about 1/3 of the coal burning power It is also built for an urgent power system.

1 is a view showing a general combined cycle power generation system.

As illustrated in FIG. 1, a general combined cycle power generation system includes a heat recovery steam (HRSG) that generates steam by using the gas turbine 10 and an arrangement of exhaust gases generated from the gas turbine 10. Generator 20 and a steam turbine 30 driven by the steam generated in the heat recovery boiler (20).

In the gas turbine 10, the air is compressed and supplied through the compressor 11, and is sent to the combustor as a natural gas of a high temperature state heated by a heater to burn and rotate the turbine 12, and by the power of the generator Primary power generation is performed by driving (13).

The heat recovery boiler 20 is discharged through the main stone 23 after the heat discharged from the gas turbine 10 is supplied and used as a heat source, and the high pressure and low pressure drum 21 of the heat recovery boiler 20 ( The fluid stored in 22 is heated by the arrangement discharged from the gas turbine 10 and converted into a vapor state, and then supplied to the steam turbine 30 at each stage through a steam pipe by a feed water pump.

The steam turbine 30 is rotated by the working fluid in the steam state to drive the generator 31 to generate a second generation, the steam discharged from the steam turbine 30 is condensed in the condenser 40, the plurality of pumps By 50, the high pressure drum 21 and the low pressure drum 22 of the heat recovery boiler 20 are supplied again.

Such conventional combined cycle power generation system has a high efficiency of about 50 to 60%, but waste heat that cannot be recycled, such as exhaust heat discharged through the main stone 23 from the heat recovery boiler 20, is generated. The further improvement of power generation efficiency by utilizing waste heat that is discarded is a big issue and task in the power plant industry.

The present invention is to solve the problems of the prior art, in the combined cycle power generation system, in particular, a composite that can improve the power generation efficiency by further power generation by recycling the latent heat of latent outlet heat in the steam turbine or waste heat generated in the condenser To provide thermal power generation system.

Combined cycle power generation system according to the present invention for achieving this object, the gas turbine for driving using natural gas as fuel; An array recovery boiler for generating steam by using an array of exhaust gases generated from the gas turbine; A steam turbine driven by steam generated by the heat recovery boiler; A generator that is generated by the power of the gas turbine and the steam turbine; A condenser for condensing the steam used in the steam turbine; A combined cycle power generation system comprising a plurality of pumps for circulating a plurality of the plurality of condensers to the heat recovery boiler, comprising: a heat exchange unit provided between the steam turbine and the condenser to circulate a portion of the saturated refrigerant delivered to the condenser; A vacuum pump provided in a first pipe provided between the steam turbine and the heat exchange part so that the saturated refrigerant at the outlet side of the steam turbine flows to the heat exchange part; A pressurizing pump provided in the second pipe (L2) provided between the heat exchanger and the condenser such that the saturated refrigerant heat-exchanged in the heat exchanger flows to the condenser side; A second steam turbine driven by ammonia vapor generated in the heat exchange unit; A second generator for generating power by the second steam turbine; It is achieved by a condenser to condense the ammonia vapor used in the second steam turbine to circulate the ammonia refrigerant to the heat exchange unit.

Preferably, in the present invention, the saturated refrigerant supplied to the heat exchange unit is characterized in that 30 ~ 40 ℃.

Preferably, in the present invention, the saturated refrigerant discharged from the pressure pump is characterized in that the pipe is provided to be delivered directly to the condenser side.

Preferably, in the present invention, the first pressure detection unit provided in the first pipe for detecting the outlet pressure of the steam turbine; A second pressure detector provided on the discharge side of the vacuum pump to detect pressure; And a pump control module for controlling the vacuum pump to induce a forward flow of saturated refrigerant by compensating the differential pressure by using the pressure signal detected by the first and second pressure detectors as an input signal.

More preferably, the present invention comprises: a third pressure detecting unit provided on the discharge side of the pressure pump for detecting pressure; And a fourth pressure detector for detecting the pressure of the condenser, wherein the pump control module compensates the differential pressure by using the pressure signals detected by the third and fourth pressure detectors as input signals, and forward flows of the saturated refrigerant in which heat exchange is performed. It characterized in that for controlling the pressure pump to induce.

In accordance with another aspect of the present invention, a combined cycle power generation system includes: a gas turbine driven by using natural gas as a fuel; An array recovery boiler for generating steam by using an array of exhaust gases generated from the gas turbine; A steam turbine driven by steam generated by the heat recovery boiler; A generator that is generated by the power of the gas turbine and the steam turbine; A condenser for condensing the steam used in the steam turbine; A plurality of pumps for circulating the plurality of the plurality of condensers to the array recovery boiler; In a combined cycle power generation system including a cooling source for circulating and supplying a refrigerant for condensing the steam of the condenser through heat exchange, a portion of the refrigerant provided between the condenser and the cooling source and transferred to the cooling source from the condenser is circulated Heat exchanger is made; A second steam turbine driven by ammonia vapor generated in the heat exchange unit; A second generator for generating power by the second steam turbine; It can be achieved by a condenser to condense the ammonia vapor used in the second steam turbine to circulate the ammonia refrigerant to the heat exchange unit.

Preferably, the present invention further includes a circulation pump for circulation of the refrigerant between the condenser and the heat exchanger.

In the combined cycle power generation system according to the present invention, the steam turbine can be driven by the ammonia refrigerant by using the latent heat of the outlet in the steam turbine, thereby increasing the power generation efficiency.

In addition, the combined cycle power generation system according to the present invention, by utilizing the waste heat of the refrigerant delivered from the condenser to the cooling source can be driven by the steam turbine by ammonia refrigerant to improve the power generation efficiency, in particular provided between the condenser and the cooling source By minimizing the impact on the refrigerant cycle circulating in the combined cycle power generation system, it is possible to provide a stable generation system without acting as a heavy load on the combined cycle power generation system according to the operation of the low-temperature closed loop power generation system. have.

1 is a view showing a general combined cycle power generation system,
2 is a configuration diagram showing a first embodiment of a combined cycle power generation system according to the present invention;
Figure 3 is a block diagram showing a second embodiment of the combined cycle power generation system according to the present invention.

The specific structure or functional description presented in the embodiment of the present invention is merely illustrative for the purpose of illustrating an embodiment according to the concept of the present invention, and embodiments according to the concept of the present invention can be implemented in various forms. And should not be construed as limited to the embodiments described herein, but should be understood to include all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Meanwhile, in the present invention, the terms first and / or second etc. may be used to describe various components, but the components are not limited to the terms. The terms may be referred to as a second element only for the purpose of distinguishing one element from another, for example, to the extent that it does not depart from the scope of the invention in accordance with the concept of the present invention, Similarly, the second component may also be referred to as the first component.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but it should be understood that there may be other elements in between something to do. On the other hand, when it is mentioned that an element is "directly connected" or "directly contacted" to another element, it should be understood that there are no other elements in between. Other expressions for describing the relationship between components, such as "between" and "between" or "adjacent to" and "directly adjacent to" should also be interpreted.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. It will be further understood that the terms " comprises ", or "having ", and the like in the specification are intended to specify the presence of stated features, integers, But do not preclude the presence or addition of steps, operations, elements, parts, or combinations thereof.

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

First Embodiment

Referring to FIG. 2, in this embodiment, the gas turbine 10, the heat recovery boiler 20, the steam turbine 30, the generator 13, 31, the condenser 40, and the condenser pump 50 are included. The combined cycle power generation system is the same as the prior art, and thus a detailed description thereof will be omitted.

On the other hand, according to the first embodiment of the combined cycle power generation system according to the present invention, the power generation is generated by the ammonia refrigerant using a saturated refrigerant provided between the steam turbine 30 and the condenser 40 and delivered to the condenser 40 as a heat source. It is characterized in that the medium-low temperature closed loop power generation system 100 is added.

The refrigerant used as the working fluid in the low-temperature closed loop power generation system of the present invention uses ammonia water, and the ammonia water has a boiling point of about 36 ° C., which is vaporized by low temperature saturated steam in the range of 30 to 40 ° C. exiting the steam turbine 30 outlet. Further developments can be made.

The low-temperature closed loop power generation system 100, the heat exchange unit 110, the vacuum pump 120, the pressure pump 130, the second steam turbine 140, the second generator 150 and the condenser 160 Include.

The heat exchanger 110 is provided between the steam turbine 30 and the condenser 40, and a portion of the saturated refrigerant used in the steam turbine 30 and delivered to the condenser 40 is supplied to the heat exchanger 110 to supply ammonia. After the heat exchange with the refrigerant is condensed in the condenser 40.

The vacuum pump 120 is provided in the first pipe L1 provided so that the saturated refrigerant at the outlet side of the steam turbine 30 flows to the heat exchange part 110 side.

In the piping system connecting the steam turbine 30 and the condenser 40, the discharge end of the steam turbine 30 is maintained at or below atmospheric pressure (about 0.8 to 0.9 bar) in order to increase the power generation efficiency of the steam turbine 30. A vacuum pump 120 is provided in the first pipe L1 so that the wet steam of 30 to 40 ° C. discharged from the steam turbine 30 may be circulated along the heat exchange unit 110.

The pressure pump 130 is provided in the second pipe L2 provided so that the saturation refrigerant having undergone heat exchange in the heat exchanger 110 flows to the condenser 40.

The pressure pump 130 maintains the pressure of the second pipe L2 at an appropriate level so that the saturated refrigerant flowing along the second pipe L2 can be smoothly transferred to the condenser 40.

In particular, in the present invention, the second pipe (L2) is connected to the pipe connected to the steam turbine 30 and the condenser (40) through the saturated refrigerant and heat exchanger 110 discharged directly from the steam turbine (30). The saturated refrigerant may be introduced into the condenser 40, but separately from the saturated refrigerant pipe L0 that is directly transmitted to the condenser 40 from the steam turbine 30, as illustrated in FIG. 2, the pressure pump 130. Saturated refrigerant discharged from the) is provided with a separate pipe (L2 ') to be delivered to the pluralizer 40 directly from the pressure pump 130, the flow of saturated refrigerant can be made more smoothly.

The second steam turbine 140 is driven by the ammonia vapor generated in the heat exchange unit 110, the second generator 150 is driven by the second steam turbine 140 to generate power.

The condenser 160 condenses the ammonia vapor used in the second steam turbine 140, and the ammonia refrigerant condensed in the condenser 160 is converted into ammonia vapor by heat exchange with a saturated refrigerant in the heat exchange unit 110. Power generation is achieved through repetition of cycles.

More preferably, the pump control module for controlling the vacuum pump 120 or the pressurized pump 130 so that the saturation refrigerant used in the steam turbine 30 can be circulated more smoothly along the heat exchange unit 110 ( 170) may be added.

To this end, the first pressure detection unit (P1) for detecting the outlet pressure of the steam turbine 30; A second pressure detector P2 is provided on the discharge side of the vacuum pump 120 to detect the pressure.

The pump control module 170 compares and determines the pressure values detected by the first and second pressure detectors P1 and P2 to compensate for the differential pressure generated at the input and output ends of the vacuum pump 120 so that the forward flow can be performed. The vacuum pump 120 can be controlled.

For example, the pump control module determines the differential pressure by using the detected pressure value of the first and second pressure detectors P1 and P2 as an input signal, and the forward flow P1 ?? P2 of the saturated refrigerant can be made. The vacuum pump 120 may be controlled in real time.

More preferably, a third pressure detection unit P3 provided on the discharge side of the pressure pump 130 for detecting pressure and a fourth pressure detection unit P4 for detecting the pressure of the condenser 40 may be further added. have.

The pump control module 170 receives the pressure values detected by the third and fourth pressure detectors P3 and P4, and the saturated refrigerant flows smoothly from the heat exchanger 110 to the condenser 40 in the forward flow (P3? Real-time control may be made to the pressure pump 130 so that? P4) can be achieved.

In the present embodiment, the fourth pressure detecting unit P4 is illustrated as being provided on the outlet side of the condenser 40, but may be installed in the condenser 40 to detect the pressure inside the condenser 40.

Second Embodiment

In the present embodiment, the gas turbine 10, the heat recovery boiler 20, the steam turbine 30, the generator 13, 31, the condenser 40, and the condenser pump 50 constituting the combined cycle power generation system are conventionally manufactured. The description is the same as the description, and thus a detailed description thereof will be omitted.

In the second embodiment of the present invention, a medium or low temperature is generated between the condenser 40 and the cooling source 60 to generate power by the ammonia refrigerant by utilizing about 40 ° C. of refrigerant delivered to the cooling source 60 as a heat source. The closed loop power generation system 200 is included.

As illustrated in FIG. 3, in the combined cycle power generation system according to the present embodiment, a portion of the refrigerant provided between the condenser 40 and the cooling source 60 and delivered from the condenser 40 to the cooling source 60 is circulated. A heat exchanger 210 to be made; A second steam turbine 220 driven by ammonia vapor generated in the heat exchange part 210; A second generator 230 in which power is generated by the second steam turbine 220; Condenser 240 to condense the ammonia vapor used in the second steam turbine 240 to circulate the ammonia refrigerant to the heat exchange unit 210.

In this embodiment, the cooling source 60 is illustrated as a cooling tower, but is not limited thereto, and sea water may be used, and well-known sea water pumps may be added to use sea water as a heat source.

In the heat exchanger 210, a portion of the refrigerant having a temperature of about 40 ° C., which is transmitted from the condenser 40 to the cooling source 60, is circulated. In this process, the refrigerant passes through the condenser 250 and exchanges ammonia vapor through heat exchange with condensed ammonia. Generates.

A circulation pump 251 may be added to the condenser 40 and the heat exchanger 210 to circulate the refrigerant.

In addition, between the condenser 40 and the heat exchanger 210, a pressure detector (not shown) such as a pressure gauge capable of detecting a pressure on the refrigerant flow, and a circulation pump 251 according to the detected pressure of the pressure detector. Pump control module (not shown) for controlling the may be added. The pump control module controls the driving of the circulation pump so that the refrigerant can be circulated smoothly according to the pressure signal detected by the pressure detector.

The second steam turbine 220, the second generator 230, and the condenser 240 are substantially the same as in the first embodiment, and the ammonia vapor drives the second steam turbine 220 to operate the second generator 230. Power generation is made through, and the ammonia vapor discharged from the second steam turbine 220 is a cycle passing through the heat exchange unit 210 after the condensation is made while passing through the condenser 240.

Thus, the low-temperature closed loop power generation system 200 provided between the condenser 40 and the cooling source 60 may utilize the low-temperature waste heat source generated in the condenser 40, in particular, the condenser 40 and the cooling source. It is provided between (60) to minimize the impact on the refrigerant cycle circulating in the combined cycle power generation system, the advantage that does not generate a large load in the operation of the combined cycle power generation system according to the operation of the low-temperature closed-loop power generation system have.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

10 gas turbine 11 compressor
12 turbine 13, 31 generator
20: heat recovery boiler 30: steam turbine
40: multiplier 50: multiple pump
60: cooling source
100, 200: Low temperature closed loop power generation system
110, 210: heat exchanger 120: vacuum pump
130: pressurized pump 140, 220: second steam turbine
150, 230: second generator 160, 240: condenser
170: pump control module 251: circulation pump
L1: First piping L2: Second piping
P1: first pressure detector P2: second pressure detector
P3: third pressure detector P4: fourth pressure detector

Claims (7)

A gas turbine driven by using natural gas as a fuel; An array recovery boiler for generating steam by using an array of exhaust gases generated from the gas turbine; A steam turbine driven by steam generated by the heat recovery boiler; A generator that is generated by the power of the gas turbine and the steam turbine; A condenser for condensing the steam used in the steam turbine; In the combined cycle power generation system comprising a plurality of pumps for circulating a plurality of the plurality of plural units to the heat recovery boiler,
A heat exchanger provided between the steam turbine and the condenser to circulate a portion of the saturated refrigerant delivered to the condenser;
A vacuum pump provided in a first pipe provided between the steam turbine and the heat exchange part so that the saturated refrigerant at the outlet side of the steam turbine flows to the heat exchange part;
A pressurizing pump provided in a second pipe provided between the heat exchanger and the condenser such that the saturated refrigerant heat-exchanged in the heat exchanger flows to the condenser side;
A second steam turbine driven by ammonia vapor generated in the heat exchange unit;
A second generator for generating power by the second steam turbine;
And a condenser for condensing the ammonia vapor used in the second steam turbine to circulate the ammonia refrigerant to the heat exchange unit. The combined cycle power generation system according to claim 1, wherein the saturated refrigerant supplied to the heat exchange part is 30 to 40 ° C. The combined cycle power generation system according to claim 1, wherein the saturated refrigerant discharged from the pressure pump is provided with a pipe so as to be directly transmitted to the condenser side. According to claim 1, A first pressure detector for detecting the outlet pressure of the steam turbine is provided in the first pipe; A second pressure detector provided on the discharge side of the vacuum pump to detect pressure; And a pump control module for controlling the vacuum pump to induce a forward flow of saturated refrigerant by compensating the differential pressure by using the pressure signal detected by the first and second pressure detectors as an input signal. 5. The apparatus of claim 4, further comprising: a third pressure detector provided on the discharge side of the pressure pump to detect pressure; Further comprising a fourth pressure detector for detecting the pressure of the condenser,
The pump control module uses the pressure signal detected by the third and fourth pressure detectors as an input signal to compensate for the differential pressure to control the pressure pump to induce the forward flow of the saturation refrigerant heat exchange is performed Power generation system. A gas turbine driven by using natural gas as a fuel; An array recovery boiler for generating steam by using an array of exhaust gases generated from the gas turbine; A steam turbine driven by steam generated by the heat recovery boiler; A generator that is generated by the power of the gas turbine and the steam turbine; A condenser for condensing the steam used in the steam turbine; A plurality of pumps for circulating the plurality of the plurality of condensers to the array recovery boiler; In the combined cycle power generation system comprising a cooling source for circulating supply of a refrigerant for condensing the steam of the condenser through heat exchange,
A heat exchanger provided between the condenser and a cooling source to circulate a portion of the refrigerant transferred from the condenser to the cooling source;
A second steam turbine driven by ammonia vapor generated in the heat exchange unit;
A second generator for generating power by the second steam turbine;
And a condenser for condensing the ammonia vapor used in the second steam turbine to circulate the ammonia refrigerant to the heat exchange unit. The combined cycle power generation system according to claim 6, further comprising a circulation pump for circulation of the refrigerant between the condenser and the heat exchanger.

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