Combined cycle power plant that performs exhaust gas recirculation

Abstract

A combined cycle power plant (100) including a gas turbine engine (102) having a compressor inlet (106) and a turbine outlet (110) configured to discharge a first exhaust gas stream (120). The heat recovery steam generator (112) is configured to receive the first exhaust gas stream (120), extract heat from the first exhaust gas stream (120) to generate steam, and discharge a second exhaust gas stream (122). The steam turbine (104) is configured to discharge a steam stream (128), the carbon recovery system (134) is configured to receive the steam stream (128), the recirculation blower (170) is configured to pressurize a portion of the second exhaust gas stream (122) and recirculate it towards the compressor inlet (106), and the air inlet blower (168) is configured to pressurize an air stream (174) flowing towards the compressor inlet (106) such that a pressurized mixed stream formed from a portion of the second exhaust gas stream (122) and the air stream (174) is received at the compressor inlet (106).

Description

Technical Field

[0001] The present disclosure generally relates to power generation systems, and more specifically to systems that recirculate pressurized exhaust gas to improve plant output.

Background Art

[0002] At least some known power plants generate energy by burning fuels containing carbon and hydrogen (such as coal, oil, peat, waste, biofuels, natural gas, etc.). Such fuels may contain oxygen, moisture, and / or contaminants in addition to carbon and hydrogen. Therefore, the combustion of such fuels may generate a gas stream containing contaminants in the form of ash, carbon dioxide (CO2), sulfur compounds (often in the form of sulfur oxides called "SOx"), nitrogen compounds (often in the form of nitrogen oxides called "NOx"), chlorine, mercury, and / or trace elements.

[0003] To remove contaminants from the gas stream, at least some known power plants may use a capture system that attempts to capture the contaminants before the exhaust stream is released into the atmosphere. For example, some known power plants may use a carbon capture system that recovers carbon dioxide (CO2) after combustion and stores the recovered CO2 underground to reduce the amount of CO2 released into the atmosphere. However, since the carbon capture process requires power, the overall efficiency of the power plant may be reduced by the process of capturing carbon, and / or the power generation capacity of the power plant may be limited. Therefore, at least some of such power plant systems are operated with a reduced power generation efficiency.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] In one aspect, a combined cycle power plant is provided that includes a gas turbine engine having a compressor inlet and a turbine outlet that discharges a first exhaust gas stream. A heat recovery steam generator is disposed downstream of the turbine engine, and the heat recovery steam generator is configured to receive the first exhaust gas stream, extract heat from the first exhaust gas stream, and discharge a second exhaust gas stream. A steam turbine is configured to discharge a steam flow. A carbon recovery system is disposed downstream of the steam turbine and is arranged to receive the steam flow. A recirculation blower is coupled downstream of the heat recovery steam generator and pressurizes a portion of the second exhaust gas stream for recirculation toward the compressor inlet. An air inlet blower is configured to pressurize an air flow flowing toward the compressor inlet, and a pressurized mixed flow is formed from a portion of the second exhaust gas stream and the air flow, and then the mixture flows into the compressor inlet. The air inlet blower is configured to pressurize an air flow flowing toward the compressor inlet, and a pressurized mixed flow is formed from a portion of the second exhaust gas stream and the air flow, and then the mixture flows into the compressor inlet.

[0006] In yet another aspect, a combined cycle power plant is provided that includes a gas turbine engine having a compressor inlet and a turbine outlet that discharges a first exhaust gas stream. A heat recovery steam generator is disposed downstream of the turbine and is configured to receive the first exhaust gas stream, extract heat from the first exhaust gas stream, and discharge a second exhaust gas stream. A steam turbine is configured to discharge a steam stream. A carbon recovery system is disposed downstream of the steam turbine and is arranged to receive the steam stream. A first cooler is disposed between the heat recovery steam generator and the carbon recovery system. The first cooler is configured to cool the second exhaust gas stream flowing toward the carbon recovery system, thereby forming a third exhaust gas stream. A recirculation blower pressurizes a portion of the third exhaust gas stream and recirculates it toward the compressor inlet. An air inlet blower is configured to pressurize an air stream flowing toward the compressor inlet, and a pressurized mixed stream is formed from a portion of the third exhaust gas stream and the air stream, and then the mixture flows into the compressor inlet.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0008] The embodiments described herein relate to a power generation system that utilizes pressurized exhaust gas recirculation to improve plant output. The basic concept is to increase (i.e., supercharge) the inlet pressure of a gas turbine compressor using both pressurized inlet air and recirculation of pressurized exhaust gas. The boost provided to the compressor increases the output of the gas turbine to a level sufficient to at least offset both the power consumption of the blower fan and the steam cycle losses due to steam transport to the carbon capture system. In one embodiment, only a fan that pressurizes the inlet air and the exhaust gas recirculation is used, thus minimizing the need for additional blower fans to pressurize the gas turbine exhaust and the heat recovery steam generator (HRSG) exhaust and the feed to the absorption tower downstream of the HRSG. In an alternative embodiment, an additional fan or a third fan may be used to pressurize the feed to the carbon capture system, or the additional fan or third fan may be used as an induced draft fan in the exhaust section. Thus, the system described herein is capable of recovering plant output lost due to exhaust gas being recirculated to the gas turbine inlet.

[0009] Unless otherwise specified, words used herein to represent approximations (such as “substantially,” “essentially,” and “approximately”) are intended to indicate that the term so modified is not intended to be absolute or complete in degree, but rather only approximate, as would be recognized by one of ordinary skill in the art. Thus, a value modified by one or more of the terms “approximately,” “about,” “substantially,” etc. should not be limited to the specific precise value. In at least some instances, the words representing approximations may correspond to the accuracy of the equipment used to measure the value. Further, unless otherwise specified, in this specification, terms such as “first,” “second,” etc. are used merely as labels and are not intended to impose sequential, positional, or hierarchical requirements on the items they refer to. Further, for example, a reference to a “second” item does not require, nor does it exclude, the presence of a “first” (i.e., lower numbered) or a “third” (i.e., higher numbered) item.

[0010] FIG. 1 is a schematic view of an exemplary combined cycle power plant 100. In an exemplary embodiment, the power plant 100 includes a gas turbine 102 and a steam turbine 104. The gas turbine 102 includes a compressor 106, a combustor 108, and a turbine 110, which are in fluid series relationship. In operation, the combustor 108 receives air from the compressor section 106 and fuel from a fuel supply section, uses the fuel and air to create a fuel-air mixture, and the fuel-air mixture burns to generate combustion gases. The combustion gases flow through the turbine 110 and are discharged from the turbine 110. In an exemplary embodiment, the power plant 100 also includes a steam cycle configuration including a heat recovery steam generator (HRSG) 112 and a steam turbine 104. In some embodiments, the steam cycle configuration can also include other components including a condenser 114 and at least one circulation pump 116.

[0011] The HRSG 112 is oriented to receive a first exhaust gas stream 120 from the gas turbine 102 and includes an inlet 118 sized accordingly. Heat is extracted from the first exhaust gas stream 120, and a second exhaust gas stream 122 flows out and is discharged through a first outlet 124 at a temperature lower than the temperature of the first exhaust gas stream 120. The HRSG 112 also includes a second outlet 126 that discharges a first steam stream 128. The steam turbine 104 receives the first steam stream 128 and then discharges a circulation stream 130. In some embodiments, the steam turbine 104 can include an additional pressure steam turbine downstream. In an exemplary embodiment, each of the gas turbine 102 and the steam turbine 104 is coupled to a generator 132 used to generate electricity.

[0012] In an exemplary embodiment, the power plant 100 also includes a carbon capture system 134. During operation, the carbon capture system 134 generates an exhaust stream 140 with reduced carbon and a carbon dioxide stream 138. The carbon capture system 134 can include one or more separators, which may be used alone or in combination with other separation processes (such as carbon dioxide selective membrane technology, absorption method, diaphragm, etc.). The exhaust stream 140 can be discharged from the carbon capture system 134 to the ambient environment. In some other embodiments, the exhaust stream 140 is discharged to the environment or other locations after further treatment. At least a portion of the carbon dioxide stream 138 can be brought to a supercritical pressure state, for example, for transportation and / or storage.

[0013] The carbon capture system 134 generally includes an absorber 142, a stripper 144, and a reboiler 146. In operation, the second exhaust gas stream 122 discharged from the HRSG 112 flows towards the absorber 142. The exhaust gas 122 can be pretreated for the removal of particulates and impurities (such as SOx and NOx) before entering the absorber 142. Further, in an exemplary embodiment, a first cooler 148 and a booster blower 150 are coupled between the HRSG 112 and the carbon capture system 134. The first cooler 148 (e.g., a quench tower) cools a portion of the exhaust gas stream 122 and supplies it to the carbon capture system 134. The booster blower 150 pressurizes the portion of the exhaust gas stream 122 before the portion is supplied to the carbon capture system 134, making it easier to control the pressure within the carbon capture system 134.

[0014] From the bottom of the absorber 142, a solvent 152 rich in carbon dioxide is discharged and sent to the stripper 144 via the pump 154. Also, from the bottom of the stripper 144, a solvent 156 low in carbon dioxide is discharged and returned to the upper part of the absorber 142 via the reboiler 146, the pump 166, and the heat exchanger 158. The absorber 142 can have a typical structure for gas-liquid contact and gas-liquid absorption. The absorber 142 and the stripper 144 can incorporate various internal components (e.g., trays, packings, and / or supports, etc.). In one embodiment, the absorber 142 absorbs carbon dioxide by countercurrent flow of the incoming exhaust gas. The stripper 144 removes carbon dioxide from the solvent 152. The absorber 142 and the stripper 144 can have various sizes based on the amount of carbon dioxide to be removed and can be sized based on various engineering design equations. Further, a single stripper 144 may also serve as a plurality of absorbers 142.

[0015] In an exemplary example, this solvent can typically be a solution or dispersion (typically water) of one or more absorbent compounds, i.e., this absorbent compound is a compound that forms an absorbent fluid in water and can enhance the ability to preferentially remove carbon dioxide from the exhaust gas compared to water alone. For example, the solvent can be, but is not limited to, monoethanolamine (MEA). To suppress the degradation of the solvent, an inhibitor can be included in the solvent.

[0016] In an exemplary embodiment, the solvent 152 is preheated by heat exchange with the solvent 156 in the countercurrent heat exchanger 158 and then supplied to the upper part of the stripper 144. The stripper 144 is a pressurizing unit in which carbon dioxide is recovered from the solvent 152. The stripper 144 generally incorporates a reboiler 146 that receives a portion of the solvent 156 flowing out from the lower part of the stripper 144. The reboiler 146 evaporates the solvent 156 and supplies the solvent vapor 160 to the stripper 144 to facilitate the separation of carbon dioxide. A single stripper may include a plurality of reboilers 146. The reboiler 146 receives the steam (such as steam from a circulation stream) supplied from the steam turbine 104, and a heat load is applied to the reboiler 146.

[0017] The steam 162 exiting from the upper part of the stripper 144 is partially condensed in the overhead condenser 165. The condensed portion of the steam 162 is returned to the stripper 144 as reflux 164. The reflux 164 can flow into the stripper 144 via an accumulator (not shown) and a pump (not shown). The carbon dioxide gas stream 138 is taken out from the condenser 165 and can be transported and / or stored.

[0018] In an exemplary embodiment, the power plant 100 also includes an air inlet blower 168, a recirculation blower 170, and a controller 172. The air inlet blower 168 pressurizes the air stream 174 flowing towards the inlet 176 of the compressor 106. In this embodiment, a portion of the second exhaust gas stream 122 is also recirculated towards the inlet 176 as an exhaust gas recirculation stream 178. The recirculation blower 170 pressurizes the exhaust gas recirculation stream 178 before it flows into the inlet 118 of the compressor 106. In some embodiments, the air stream 174 and the exhaust gas recirculation stream 178 are mixed to form a pressurized mixed stream vapor (not shown), and then the mixture flows into the compressor inlet. Thus, the boost at the compressor inlet promotes an increase in the power density of the power plant 100.

[0019] However, the power consumption due to the operation of the blowers 150, 168, and 170 may also reduce the efficiency of the power plant. Without being bound by a particular theory, it is believed that due to the pressurization received at the inlet 118, the output of the power plant 100 can be improved to be greater than the efficiency reduction caused by the power consumption of the blowers during the operation of the power plant 100 and the steam cycle losses.

[0020] In an exemplary embodiment, the power plant 100 also includes a controller 172 that monitors and / or controls the operation of the power plant 100. For example, the controller 172 can monitor the power consumption of the blowers 150, 168, and / or 170, and can also determine, for example, the steam cycle losses due to the exhaust stream 130 going to the carbon capture system 134. The controller 172 can dynamically determine the power consumption and the steam cycle losses and adjust the operation of the power plant 100 accordingly. Thus, in one embodiment, the controller 172 variably adjusts the operation of the blowers 150, 168, and / or 170 to improve the plant output to the extent that it can accommodate the power consumption and the steam cycle losses as a result of the compressor 106 being boosted. That is, the controller 172 can adjust the flow rate of the exhaust gas recirculation flow 178 and / or the air flow 174 going to the compressor inlet to improve the output of the power plant 100 such that it is greater than the losses incurred by the power consumption of the blowers and the steam cycle losses. In an exemplary embodiment, the size of the blowers 150, 168, and / or 170, and / or the overall size of the recirculation line is variably selected such that a predetermined desired mixture can be supplied with minimal control operation at base load (i.e., full boost). By modulating the blower speed and / or changing the position of the blower guide vanes (not shown), the flow rate when the power is reduced can be managed and the boost can be reduced. At least at some of the reduced loads and at reduced loads lower than at least some of the reduced loads, the power supply to at least one of the blowers 168, 170, 175 (shown in FIG. 5) and / or optionally the blower 190 (shown in FIG. 6) can be stopped and the recirculation flow control can be implemented by the damper of the EGR duct. In an exemplary embodiment, the plant output is generally proportional to the total amount of fuel burned, which is constrained by the gas flow rate at the compressor inlet. When the EGR and the inlet blower 168 and / or blower 170 or blower 175 cause the inlet pressure to be greater than atmospheric pressure, the gas flow increases substantially linearly from the compressor to the combustor, and as a result, the power output increases linearly.More generally, such an effect is similar to operating a power plant at a physically low altitude where the air density is higher than the air density at sea level or higher than the actual density at the location of the power plant.

[0021] FIG. 2 is a schematic diagram of another exemplary combined cycle power plant 100. In the exemplary embodiment, the power plant 100 includes an air inlet blower 168 and a recirculation blower 170, but does not include a booster blower 150 (the blower 150 shown in FIG. 1). In the embodiment shown in FIG. 1, whether to include the blower 150 is related to the design internal pressure capacity of the HRSG, the GT exhaust duct, and the absorber 142, and the draft loss until these facilities discharge clean exhaust to the atmosphere. In FIG. 2, the exhaust system of the power plant 100 is designed to operate at a slightly increased pressure compared to the power plant 100 shown in FIG. 1, and thus, the blower 150 can be eliminated to simplify the system and improve reliability. In the embodiment shown in FIG. 2, the performance should also generally improve to some extent. This is because the power lost in the turbine expander 110 should be less than the power that would be consumed by including the blower 150. As a result, in the embodiment of FIG. 2, it is easier to increase the output power as a result of the compressor boost.

[0022] Figures 3 and 4 are schematic diagrams of another exemplary combined cycle power plant 100. In an exemplary embodiment, the power plant 100 includes a second cooler 180 (such as a quench tower) that promotes cooling of the exhaust gas recirculation flow 178 before the exhaust gas recirculation flow 178 enters the compressor inlet. By independently controlling the temperature of the EGR gas at the inlet 176 by the cooler 180 and the temperature of the EGR gas in the absorber 142 by the cooler 148, the temperature of each stream can be easily optimized. The second cooler 180 may be disposed between the HRSG 112 and the recirculation blower 170 as shown in FIG. 3, or may be disposed between the recirculation blower 170 and the compressor inlet as shown in FIG. 4. By disposing the second cooler 180 between the recirculation blower 170 and the compressor inlet, the temperature rise of the exhaust gas recirculation flow 178 caused by the pressurization induced by the recirculation blower 170 can be suppressed. Although adding equipment increases the cost and complexity of the power plant 100, the advantages of incorporating the cooler 180 before or after the blower 170 are greater than these costs, because the temperature of the cooled mixed inlet gas being applied to the compressor 106 is beneficial to the power output (for example, the density of the gas increases and the boost pressure required to obtain the same plant output is reduced). Cooling can also reduce the moisture content of the EGR stream by condensation.

[0023] FIGS. 5 and 6 are schematic diagrams of another exemplary combined cycle power plant 100. More specifically, in the exemplary embodiment shown in FIG. 5, the power plant 100 pressurizes the exhaust gas recirculation flow 178 and the inlet air flow 174 in a single boost blower or compressor 175, and after this pressurization, the combined flow 179 flows into the compressor inlet. By using the blower 175, the net plant output can be increased. In the exemplary embodiment, the inlet air flow 174 merges with the exhaust gas recirculation flow 178 after flowing through the inlet filter 181. Although adding equipment may increase the complexity of the power plant 100, the advantage that the number of blowers used by the power plant 100 is reduced is greater than this loss. Further, in the case of a single blower 175, there is flexibility in arrangement regarding the position of the single blower relative to the compressor inlet. For example, additional inlet adjustment can be made before the recirculation flow 178 flows into the compressor inlet. Further, depending on the operating conditions of the power plant 100, the single blower 175 can reduce costs, facilitate maintenance, and / or provide easy access. Further, the blower 175 can stop supplying power according to the requirements of the load of the power plant, similar to other blowers used in the power plant 100 of each embodiment described herein. In this embodiment, the exhaust recirculation supply connection downstream of the cooler 148 can promote the cooling of the exhaust flow 148 before the exhaust flow flows into the absorber 142 and / or before the exhaust flow flows into the turbine inlet by the steam 178. Such an arrangement can reduce and / or simplify the complexity of the exhaust system of the power plant 100.

[0024] In the embodiment shown in FIG. 6, the blower 175 (shown in FIG. 5) is removed, and a compressor having a shaft drive type boost blower 190 is included to pressurize the flow 179. In one embodiment, the blower 190 includes a gear for reducing the speed of the blower 190 with respect to the power train. Although the blower 190 reduces the options for inlet gas treatment after passing through the blower, since the blower 190 is coupled to the main compressor inlet 106 near the main compressor inlet 106, the blower 190 makes the power plant 100 more compact compared to other embodiments. Further, the axial shaft drive type compressor improves the overall efficiency of the power plant by reducing motor losses, and since the design of the axial shaft drive type compressor is generally expected to be more efficient compared to known stand-alone blowers. Further, a dedicated shaft drive type booster can improve the design flexibility to optimize the boost pressure so that the overall output of the power plant increases, but it is more difficult to stop the power supply of such a booster at low plant loads where power boosting is not required.

[0025] The embodiments described herein relate to a power generation system that utilizes recirculation of pressurized exhaust gas to enhance plant output. By the boost provided to the gas turbine compressor inlet pressure by both pressurized inlet air and recirculation of pressurized exhaust gas, it is possible to increase the gas turbine output sufficient to at least offset both the power consumption of the blower fan and the steam cycle losses due to steam transport to the carbon capture system. For example, the boost increases the output density of the power plant, which is believed to be improvable on a $ / kW basis. Accordingly, by adjusting the boost provided by the blowers described herein, a regulating valve is provided that can be used to improve part load performance.

[0026] Other aspects of the present disclosure are provided by the subject matter of the following embodiments. [Embodiment 1] A combined cycle power plant comprising a gas turbine engine including a compressor inlet and a turbine outlet for discharging a first exhaust gas stream, a heat recovery steam generator disposed downstream of the turbine, the heat recovery steam generator being configured to receive the first exhaust gas stream, extract heat from the first exhaust gas stream to generate steam, and discharge a second exhaust gas stream, a steam turbine configured to receive steam from the heat recovery steam generator and discharge a steam stream, a carbon recovery system disposed downstream of the steam turbine and configured to receive the steam stream, a recirculation blower coupled downstream of the heat recovery steam generator for pressurizing a portion of the second exhaust gas stream and recirculating it toward the compressor inlet, and an air inlet blower configured to pressurize an air stream flowing toward the compressor inlet, wherein a pressurized mixed stream is formed from a portion of the second exhaust gas stream and the air stream, and then the mixture flows into the compressor inlet, the combined cycle power plant including the air inlet blower. [Embodiment 2] The combined cycle power plant of Embodiment 1 further includes a controller configured to monitor power consumption of the recirculation blower and the air inlet blower, determine steam cycle losses resulting from discharging the steam stream toward the carbon recovery system, and adjust the flow rate of the exhaust gas stream flowing and recirculating toward the compressor inlet to improve operation of the combined cycle power plant. [Embodiment 3] The combined cycle power plant of Embodiment 1 or 2 further includes a first cooler coupled between the heat recovery steam generator and the carbon recovery system, the first cooler being configured to cool the second exhaust gas stream flowing toward the carbon recovery system. [Embodiment 4] The combined cycle power plant further includes a booster blower in fluid communication with the first cooler, and the booster blower is configured to pressurize the second exhaust gas flow flowing toward the carbon recovery system, the combined cycle power plant according to any one of Embodiments 1 to 3. [Embodiment 5] The combined cycle power plant further includes a second cooler configured to cool a part of the second exhaust gas flow that flows and recirculates toward the compressor inlet, the combined cycle power plant according to any one of Embodiments 1 to 4. [Embodiment 6] The second cooler is present between the heat recovery steam generator and the recirculation blower, the combined cycle power plant according to any one of Embodiments 1 to 5. [Embodiment 7] The second cooler is present between the recirculation blower and the compressor inlet, the combined cycle power plant according to any one of Embodiments 1 to 6. [Embodiment 8] A combined cycle power plant, comprising a gas turbine engine including a compressor inlet and a turbine outlet arranged to discharge a first exhaust gas flow, a heat recovery steam generator arranged downstream of the gas turbine engine, the heat recovery steam generator being configured to receive the first exhaust gas flow, extract heat from the first exhaust gas flow to generate steam, and discharge a second exhaust gas flow, a recirculation blower arranged downstream of the heat recovery steam generator for pressurizing a part of the second exhaust gas flow and recirculating it toward the compressor inlet, and an air inlet blower configured to pressurize an air flow toward the compressor inlet, wherein a pressurized mixed flow is formed from a part of the second exhaust gas flow path and the air flow, and then the mixture flows into the compressor inlet, the combined cycle power plant including the air inlet blower. [Embodiment 9] A combined cycle power plant according to any one of Embodiments 1 to 8, including a steam turbine arranged to discharge a steam flow, and a carbon recovery system arranged downstream of the steam turbine and arranged to receive the steam flow. [Embodiment 10] The combined cycle power plant further includes a controller, and the controller is configured to monitor power consumption of a recirculation blower and an air inlet blower, determine steam cycle losses caused by discharging the steam flow toward the carbon recovery system, and adjust at least one of a flow rate and a temperature of the exhaust gas flow flowing in recirculation toward the compressor inlet to improve operation of the combined cycle power plant, a combined cycle power plant according to any one of Embodiments 1 to 9. [Embodiment 11] The combined cycle power plant further includes a first cooler coupled between the heat recovery steam generator and the carbon recovery system, and the first cooler is configured to cool the second exhaust gas flow toward the carbon recovery system, a combined cycle power plant according to any one of Embodiments 1 to 10. [Embodiment 12] The combined cycle power plant further includes a booster blower in fluid communication with the first cooler, and the booster blower is configured to pressurize the second exhaust gas flow flowing toward the carbon recovery system, a combined cycle power plant according to any one of Embodiments 1 to 11. [Embodiment 13] The combined cycle power plant further includes a second cooler configured to cool a part of the second exhaust gas flow flowing in recirculation toward the compressor inlet, a combined cycle power plant according to any one of Embodiments 1 to 12. [Embodiment 14] The second cooler exists between the heat recovery steam generator and the recirculation blower, a combined cycle power plant according to any one of Embodiments 1 to 13. [Embodiment 15] The second cooler is a combined cycle power plant according to any one of Embodiments 1 to 14, which exists between the recirculation blower and the compressor inlet. [Embodiment 16] A combined cycle power plant, comprising a gas turbine engine including a compressor inlet and a turbine outlet for discharging a first exhaust gas stream, a heat recovery steam generator disposed downstream of the turbine, the heat recovery steam generator being configured to receive the first exhaust gas stream, extract heat from the first exhaust gas stream to generate steam, and discharge a second exhaust gas stream, a steam turbine disposed to discharge a steam stream, a carbon recovery system disposed downstream of the steam turbine and configured to receive the steam stream, a first cooler disposed between the heat recovery steam generator and the carbon recovery system, the first cooler being configured to cool a first portion of the second exhaust gas stream flowing toward the carbon recovery system, thereby forming a third exhaust gas stream, a recirculation blower coupled downstream of the heat recovery steam generator and configured to pressurize a second portion of the second exhaust gas stream and recirculate it toward the compressor inlet, and an air inlet blower configured to pressurize an air stream flowing toward the compressor inlet, wherein a pressurized mixed stream is formed from the second portion of the second exhaust gas stream and the air stream, and then the mixture flows into the compressor inlet. [Embodiment 17] The combined cycle power plant further includes a controller, the controller being configured to monitor the power consumption of the recirculation blower and the air inlet blower, determine a steam cycle loss caused by discharging the steam stream toward the carbon recovery system, and adjust at least one of the flow rate and temperature of the exhaust gas stream flowing and recirculating toward the compressor inlet to increase the net output of the combined cycle power plant so as to exceed the power consumption of the blower and the steam cycle loss. [Embodiment 18] The composite cycle power plant according to any one of Embodiments 1 to 17 further includes a second cooler configured to cool a second portion of the second exhaust gas stream that flows and recirculates toward the compressor inlet. [Embodiment 19] The composite cycle power plant according to any one of Embodiments 1 to 18, wherein the second cooler is present between the heat recovery steam generator and the recirculation blower. [Embodiment 20] The composite cycle power plant according to any one of Embodiments 1 to 19, wherein the second cooler is present between the recirculation blower and the compressor inlet.

[0027] The above description is for illustrative purposes only, and those skilled in the art will recognize that the described embodiments can be modified without departing from the scope of the disclosed invention. Those skilled in the art will appreciate, in view of the present disclosure, that variations within the scope of the present invention are obvious and are intended to be included within the scope of the claims.

[0028] Specific features of various embodiments of the present invention may be shown in some drawings and not in others, but this is for convenience only. Further, reference to the above "one embodiment" is not intended to exclude the existence of additional embodiments that also incorporate the recited features. In accordance with the principles of the present invention, any feature in one drawing can be referenced and / or claimed in combination with any feature in another drawing.

[0029] The present invention has been described with respect to various specific embodiments, but those skilled in the art will recognize the spirit of the claims and that modifications can be made within the scope thereof.

Description of Reference Numerals

[0030] 102 Gas turbine 104 Steam turbine 108 Combustor 112 Heat Recovery Steam Generator (HRSG) 114 Condenser 116 Circulation Pump 118 Inlet 120 First Exhaust Gas Stream 124 First Outlet 126 Second Outlet 128 First Steam Stream 132 Generator 134 Carbon Recovery System 140 Exhaust Stream 142 Absorber 144 Stripper 146 Reboiler 152 Solvent 154 Pump 160 Solvent Vapor 162 Steam 164 Reflux 166 Pump 172 Controller 176 Inlet 181 Inlet Filter

Claims

1. A combined cycle power plant (100), A gas turbine engine (102) including a compressor inlet (106) and a turbine outlet (110) that discharges a first exhaust gas flow (120), A heat recovery steam generator (112) is located downstream of the gas turbine engine (102), and the heat recovery steam generator (112) is Receiving the first exhaust gas flow (120), To extract heat from the first exhaust gas flow (120) and generate steam, To discharge a second exhaust gas flow (122) A heat recovery steam generator (112) configured to perform the following: A steam turbine (104) is arranged to receive steam from the heat recovery steam generator (112) and discharge a steam flow (128). A carbon capture system (134) is positioned downstream of the steam turbine (104) and is configured to receive the steam flow (128). A recirculation fan (170) is coupled downstream of the heat recovery steam generator (112) to pressurize a portion of the second exhaust gas flow (122) and recirculate it toward the compressor inlet (106), and An air inlet blower (168) configured to pressurize an airflow (174) flowing toward the compressor inlet (106), wherein a pressurized mixed flow is formed from a portion of the second exhaust gas flow (122) and the airflow (174), and the mixture then flows into the compressor inlet (106). A combined cycle power plant (100), including a combined cycle power plant.

2. The combined cycle power plant (100) further includes a controller (172), and the controller (172) To monitor the power consumption of the recirculation fan (170) and the air inlet fan (168), To determine the steam cycle loss resulting from the discharge of the steam flow (128) toward the carbon recovery system (134), and To improve the operation of the combined cycle power plant (100) by adjusting the flow rate of the exhaust gas flow that flows toward the compressor inlet (106) and is recirculated. A combined cycle power plant (100) according to claim 1, configured to perform the following:

3. The combined cycle power plant (100) according to claim 1, further comprising a first cooler (148) coupled between the heat recovery steam generator (112) and the carbon recovery system (134), wherein the first cooler (148) is configured to cool the second exhaust gas flow (122) toward the carbon recovery system (134).

4. The combined cycle power plant (100) according to claim 3, further comprising a booster blower (150) in fluid communication with the first cooler (148), wherein the booster blower (150) is configured to pressurize the second exhaust gas flow (122) flowing toward the carbon capture system (134).

5. The combined cycle power plant (100) according to claim 1, further comprising a second cooler (180) configured to cool a portion of the second exhaust gas flow (122) that flows toward and recirculates toward the compressor inlet (106).

6. The combined cycle power plant (100) according to claim 5, wherein the second cooler (180) is located between the heat recovery steam generator (112) and the recirculation blower (170).

7. The combined cycle power plant (100) according to claim 5, wherein the second cooler (180) is located between the recirculation fan (170) and the compressor inlet (106).

8. A combined cycle power plant (100), A gas turbine engine (102) including a compressor inlet (106) and a turbine outlet (110) arranged to discharge a first exhaust gas flow (120), A heat recovery steam generator (112) is located downstream of the gas turbine engine (102), and the heat recovery steam generator (112) is Receiving the first exhaust gas flow (120), To extract heat from the first exhaust gas flow (120) and generate steam, To discharge a second exhaust gas flow (122) A heat recovery steam generator (112) configured to perform the following: A recirculation fan (170) is positioned downstream of the heat recovery steam generator (112) to pressurize a portion of the second exhaust gas flow (122) and recirculate it toward the compressor inlet (106), and An air inlet blower (168) configured to pressurize the airflow (174) directed toward the compressor inlet (106), wherein a pressurized mixed flow is formed from a part of the second exhaust gas passage (122) and the airflow (174), and the mixture then flows into the compressor inlet (106). A combined cycle power plant (100), including a combined cycle power plant.

9. A steam turbine (104) is positioned to discharge a steam flow (128), and A carbon capture system (134) is positioned downstream of the steam turbine (104) and is configured to receive the steam flow (128). A combined cycle power plant (100) according to claim 8, including the above.

10. The combined cycle power plant (100) further includes a controller (172), and the controller (172) To monitor the power consumption of the recirculation fan (170) and the air inlet fan (168), To determine the steam cycle loss resulting from the discharge of the steam flow (128) toward the carbon recovery system (134), and To improve the operation of the combined cycle power plant (100) by adjusting at least one of the flow rate and temperature of the exhaust gas flow that flows toward and recirculates towards the compressor inlet (106). A combined cycle power plant (100) according to claim 9, configured to perform the following:

11. The combined cycle power plant (100) according to claim 10, further comprising a first cooler (148) coupled between the heat recovery steam generator (112) and the carbon recovery system (134), wherein the first cooler (148) is configured to cool the second exhaust gas flow (122) toward the carbon recovery system (134).

12. The combined cycle power plant (100) according to claim 11, further comprising a booster blower (150) in fluid communication with the first cooler (148), wherein the booster blower (150) is configured to pressurize the second exhaust gas flow (122) flowing toward the carbon capture system (134).

13. The combined cycle power plant (100) according to claim 10, further comprising a second cooler (180) configured to cool a portion of the second exhaust gas flow (122) that flows toward and recirculates toward the compressor inlet (106).

14. The combined cycle power plant (100) according to claim 13, wherein the second cooler (180) is located between the heat recovery steam generator (112) and the recirculation blower (170).

15. The combined cycle power plant (100) according to claim 13, wherein the second cooler (180) is located between the recirculation fan (170) and the compressor inlet (106).

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