Combined cycle power plant with exhaust gas recirculation intercooling

Abstract

A combined cycle power plant (100) includes a gas turbine engine (102) including a compressor (106) having a compressor inlet (168), a compressor outlet (170), and an inter-stage inlet (172) defined between the compressor inlet and the compressor outlet. The turbine (110) also includes a turbine outlet configured to discharge the first exhaust gas stream (112) therefrom. The heat recovery steam generator (114) is configured to receive the first exhaust gas stream (112), extract heat from the first exhaust gas stream (112), and discharge the second exhaust gas stream (120) therefrom. The recirculation compressor (404) pressurizes a first portion of the second exhaust gas flow (120) for recirculation toward the compressor interstage inlet (172), or the intake compressor (174) pressurizes the air flow directed toward the compressor interstage inlet (172). The first cooler (148) cools a flow directed to the compressor (106), thereby defining a cooling flow (180), where the first cooler (148) provides the cooling flow (180) to an inter-stage inlet (172) of the compressor (106).

Description

Background Art

[0001] The present disclosure relates generally to power generation systems and, more particularly, to systems that use cooling air or recirculated exhaust gas for compressor intercooling.

[0002] Gas turbine systems are used to generate power and typically include a compressor, a combustor, and a turbine. Operation of gas turbine systems at higher operating temperatures typically improves performance, efficiency, and power output. Therefore, during operation, various gas path components in the system may be subjected to high temperature flows. Over time, continued exposure to high temperature flows may over-strain the components and / or reduce their service life. Therefore, at least some known gas turbine components that are subjected to high temperature flows are cooled so that the gas turbine system can continue to operate at elevated temperatures. For example, some components may be provided with compressor exhaust, etc., for cooling purposes. However, any air that is compressed in the compressor and not used to generate combustion gases typically reduces the overall efficiency of the gas turbine system. Summary of the invention

[0003] In one aspect, a combined cycle power plant is provided, the combined cycle power plant including a gas turbine engine, the gas turbine engine including: a compressor having a compressor inlet, a compressor outlet, and an interstage inlet defined between the compressor inlet and the compressor outlet; and a turbine outlet, the turbine outlet being oriented to discharge a first exhaust gas stream therefrom. A heat recovery steam generator receives the first exhaust gas stream therein, extracts heat from the first exhaust gas stream, and discharges a second exhaust gas stream therefrom. A recirculation compressor pressurizes a first portion of the second exhaust gas stream for recirculation toward the compressor, and a first cooler cools a first portion of the second exhaust gas stream after compression, thereby defining a cooled exhaust gas stream, wherein the first cooler discharges the cooled exhaust gas stream to the interstage inlet of the compressor.

[0004] In another aspect, a gas turbine assembly is provided, the gas turbine assembly comprising a gas turbine engine. The gas turbine engine comprises a compressor having a compressor inlet, a compressor outlet, and an interstage inlet defined between the compressor inlet and the compressor outlet, the gas turbine engine further comprising a turbine outlet oriented to discharge a first exhaust gas stream therefrom. The intake compressor pressurizes the stream directed toward the compressor. A first cooler cools the compressed stream discharged from the intake compressor, thereby defining a pressurized cooling stream, wherein the first cooler discharges the pressurized cooling stream to the interstage inlet of the compressor.

[0005] In another aspect, a combined cycle power plant is provided, the combined cycle power plant including a gas turbine engine, the gas turbine engine including: a compressor having a compressor inlet, a compressor outlet, and an interstage inlet defined between the compressor inlet and the compressor outlet; and a turbine outlet, the turbine outlet being configured to discharge a first exhaust gas stream therefrom. A heat recovery steam generator receives the first exhaust gas stream therein, extracts heat from the first exhaust gas stream, and discharges a second exhaust gas stream therefrom. At least one of a recirculation compressor and an intake compressor, the recirculation compressor pressurizing a first portion of the second exhaust gas stream for recirculation toward the compressor, and the intake compressor pressurizing an ambient air stream toward the compressor. A first cooler cools at least one of the ambient air stream or the first portion of the second exhaust gas stream, thereby defining a cooled exhaust gas stream, wherein the first cooler discharges the cooled exhaust gas stream to the interstage inlet of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a schematic diagram of an exemplary combined cycle power plant including an exemplary gas turbine assembly.

[0007] Figure 2 It is available with Figure 1 Schematic diagram of an alternative gas turbine assembly for use with a combined cycle power plant shown in .

[0008] Figure 3 It is available with Figure 1 A schematic diagram of another alternative gas turbine assembly for use with a combined cycle power plant is shown in .

[0009] Figure 4 is a schematic diagram of an alternative combined cycle power generation plant including a gas turbine assembly.

[0010] Figure 5 is a schematic diagram of another alternative combined cycle power plant including a gas turbine assembly.

[0011] Figure 6 is a schematic diagram of another alternative combined cycle power plant including a gas turbine assembly. DETAILED DESCRIPTION

[0012] Embodiments described herein relate to power generation systems that use injected cooling air or recirculated exhaust gas for compressor intercooling. Although exhaust gas recirculation is traditionally provided to the inlet of the gas turbine, the system described herein compresses the recirculated exhaust gas so that it can be directed to the interstage compressor intake after the gas has been cooled. This effectively converts a simple Brayton cycle engine into an intercooled engine. Alternatively, pressurized and cooled ambient air can be provided to the compressor interstage intake.

[0013] The benefits of the resulting compressor interstage inlet or recirculated exhaust gas inlet of cooled ambient air to the gas turbine include: a) increased power by reducing the working fluid temperature of the cooling flow inlet, and reducing the compressor outlet temperature, the combination of which enables more fuel to be burned; b) reduced physical size of the exhaust gas recirculation line / piping system compared to recirculation to the compressor inlet, thereby reducing cost and facilitating exhaust line routing; c) reduced gas temperature within the compressor and at the compressor discharge, thereby reducing rotor temperatures and extending the service life of the gas turbine rotors and hot gas path components; and d) suitable for use in conventional gas turbine combined cycle systems without exhaust gas recirculation by directing after-cooled ambient air rather than exhaust gas into the boost compressor, particularly suitable for any engine with compressor emission limitations and / or any turbine operating in an environment where hot weather output is valuable.

[0014] Unless otherwise indicated, approximate language as used herein, such as "substantially", "substantially" and "about" indicate that as will be recognized by those of ordinary skill in the art, the terms so modified may apply only to approximate degrees, rather than absolute or perfect degrees. Therefore, the values ​​modified by one or more terms (such as "about", "approximately" and "substantially") are not limited to the specified precise values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. In addition, unless otherwise indicated, the terms "first", "second", etc. are used only as tags in this article, and are not intended to impose order, position or hierarchical requirements on the items to which these terms are related. In addition, for example, a reference to a "second" item does not require or exclude the existence of, for example, a "first" or lower numbered item or a "third" or higher numbered item.

[0015] Figure 1 1 is a schematic diagram of an exemplary combined cycle power plant 100. In an exemplary embodiment, the power plant 100 includes a gas turbine assembly 102 and a steam turbine 104. The gas turbine assembly 102 includes a compressor 106, a combustor 108, and a turbine 110 coupled together in a series flow relationship. In operation, the combustor 108 receives air from the compressor section 106 and receives fuel from the fuel supply, and mixes the fuel and air to form a fuel-air mixture, which is burned to generate combustion gases. The combustion gases are directed through the turbine 110 and discharged from the turbine 110 as a first exhaust gas stream 112. In an exemplary embodiment, the power plant 100 also includes a steam cycle arrangement, which includes a heat recovery steam generator (HRSG) 114 and the steam turbine 104. In some embodiments, the steam cycle arrangement may also include other components, including a condenser 116 and at least one circulating pump 117. In addition, in other embodiments, the steam cycle arrangement may also include at least one additional HRSG 114.

[0016] In an exemplary embodiment, the HRSG 114 includes an inlet 118 that receives a first exhaust gas stream 112 from the gas turbine assembly 102. Heat is extracted from the first exhaust gas stream 112, and a second exhaust gas stream 120 is discharged from a first outlet 122. The temperature of the second exhaust gas stream 120 is lower than the temperature of the first exhaust gas stream 112 entering the inlet 118. The HRSG 114 also includes a second outlet 124 that discharges a first steam stream 126. The steam turbine 104 receives the first steam stream 126 and then discharges an interstage extraction stream 128 therefrom. Any steam that is not extracted using stream 128 continues to expand to condensation in the condenser 116. In some embodiments, the steam turbine 104 may include an additional steam inlet from the HRSG 114. In an exemplary embodiment, both the gas turbine assembly 102 and the steam turbine 104 are coupled to a generator 132 that generates electricity using a working fluid flowing through each. Alternatively, the turbine assembly 102 and the steam turbine 104 may be located on separate shafts, each of which is coupled to a separate generator.

[0017] In an exemplary embodiment, the power generation device 100 also includes a carbon capture system 134. During operation, the carbon capture system 134 produces a carbon dioxide stream 138. The carbon capture system 134 may include one or more separators, which are used either alone or in combination with other separation processes (such as carbon dioxide selective membrane technology, absorption processes, diaphragms, etc.). The waste gas stream or carbon-depleted waste gas stream 140 can be discharged from the carbon capture system 134 into the surrounding environment. The waste gas stream 140 can also be further processed before being discharged to the environment or elsewhere. For example, at least a portion of the carbon dioxide stream 138 can be increased to a supercritical pressure for transportation and / or storage.

[0018] The carbon capture system 134 typically includes an absorber 142, a stripper 144, and a stripper reboiler 146. In operation, the second exhaust gas stream 120 discharged from the HRSG 114 is directed toward the absorber 142. The exhaust gas can be pre-treated to remove particles and impurities, such as SOx and NOx, before entering the absorber 142. In addition, in an exemplary embodiment, a first cooler 148 is connected between the HRSG 114 and the carbon capture system 134. Alternatively, the carbon capture system 134 may include at least one booster blower (not shown) to pressurize the flow directed toward the carbon capture system 134. The first cooler 148 can be, but is not limited to, a quench tower. The first cooler 148 cools a portion of the second exhaust gas stream 120 that will be directed toward the carbon capture system 134. A solvent 152 rich in carbon dioxide is discharged from the absorber 142 and then directed to the stripper 144 via a pump 154. The solvent 156 lean in carbon dioxide is discharged from the stripper 144 and is directed back to the upper portion of the absorber 142 via a reboiler 146, a pump 166 and a heat exchanger 158. The absorber 142 can be any typical configuration for providing gas-liquid contact and absorption. The absorber 142 and the stripper 144 can, for example, be combined with a variety of internal components, such as trays, fillers and / or carriers. In one embodiment, the absorber 142 absorbs carbon dioxide via a countercurrent from the incoming exhaust gas. The stripper 144 removes carbon dioxide from the solvent 152. The absorber 142 and the stripper 144 can be variably sized based on the amount of carbon dioxide to be removed, and can be sized according to various engineering design formulas. In addition, a single stripper 144 can be used to be connected in parallel to multiple absorbers 142.

[0019] The solvent may be a solution or dispersion of one or more absorbent compounds, typically in water. More specifically, the solvent may be any compound that, when mixed with water, produces an absorbent fluid that enhances the ability of the fluid to preferentially remove carbon dioxide from the exhaust gas compared to water alone. For example, the solvent may be, but is not limited to, monoethanolamine (MEA). An inhibitor may be included in the solvent to inhibit degradation of the solvent.

[0020] In an exemplary embodiment, the solvent 152 is preheated relative to the solvent 156 in a countercurrent heat exchanger 158 and then directed to the stripper 144. The stripper 144 is a pressurized unit in which carbon dioxide is recovered from the solvent 152. The stripper 144 typically includes a reboiler 146 that receives a portion of the solvent 156 exiting the stripper 144. The reboiler 146 evaporates the solvent 156 and directs the solvent vapor 160 back to the stripper 144 to facilitate increased carbon dioxide separation. A single stripper may be coupled to more than one reboiler 146. The reboiler 146 receives steam, such as steam from the steam turbine 104 via stream 128, to provide a heat duty in the reboiler 146.

[0021] The vapor 162 exiting the stripper 144 is partially condensed in the condenser 136. The condensed portion of the vapor 162 is returned to the stripper 144 as reflux 164. The reflux 164 may be diverted through an accumulator (not shown) and a pump (not shown) prior to entering the stripper 144. A carbon dioxide stream 138 is removed from the condenser 136 for transport and / or storage after compression.

[0022] In an exemplary embodiment, the compressor 106 includes an inlet 168, an outlet 170, and an interstage inlet 172 defined between the inlet and the outlet. The power generation device 100 includes an intake compressor 174 and a controller 176. Depending on the use in the device 100, the intake compressor 174 can be configured to be used as a recirculation compressor. In an exemplary embodiment, a cooler 178 (also referred to as an aftercooler) is coupled between the intake compressor 174 and the interstage inlet 172. The cooler 178 cools the pressurized air discharged from the compressor 174 to define a cooled intake air flow 180. More specifically, the cooler 178 discharges the cooling flow 180 toward the interstage inlet 172 to facilitate improving the performance of the device 100, as described herein.

[0023] However, the power consumption from the operation of any boost blower and / or compressor 174 will reduce the plant output. The interstage cooling provided to compressor 106 by compressor 106 and its aftercooler 178 facilitates improving the output of power plant 100 by reducing the compression work in compressor 174 and by enabling more fuel to be burned in combustor 108.

[0024] For example, the controller 176 can monitor the power consumption of any booster blower and / or compressor 174 (and any large auxiliary equipment in a particular device), and can also determine, for example, the steam cycle losses caused by discharging the steam flow 128 toward the carbon capture system 134. The controller 176 can also dynamically determine the power consumption and steam cycle losses, and adjust the operation of the power generation device 100 accordingly. Therefore, in one embodiment, the operation of any booster blower and / or compressor 174 (and / or any other large auxiliary load) is adjusted by the controller 176 so as to increase the device output to a level that overcomes the power consumption and steam cycle losses. That is, the controller 176 can selectively adjust the flow of any stream directed to the compressor 106 as described herein to provide an improvement in the output of the power generation device. In an exemplary embodiment, the use of cooling injection should increase the device output boost by at least about 5% to about 10% compared to providing approximately the same exhaust gas flow recirculation to the gas turbine inlet. Additionally, because the temperature of the compressor exhaust discharge may be more easily controlled, greater performance improvements may be achieved during hot weather periods that may typically be limited in at least some known power generation systems.

[0025] An exemplary gas turbine parameter that can be monitored to determine improvements in gas turbine output is the compressor discharge temperature. In an exemplary embodiment, the power plant 100 includes a sensor (not shown) coupled to the outlet 170 for monitoring the temperature of the compressed gas discharged therefrom. The controller 176 then adjusts the cooling flow 180 provided to the interstage inlet 172 to maintain the compressor discharge temperature within a predetermined temperature range. The controller 176 facilitates extending the service life of components within the power plant 100. Thus, flow regulation provides the operator of the power plant 100 with options to use when determining how to optimize the performance of the power plant 100.

[0026] It should be noted that the gas turbine assembly 102 may be used independently of the HRSG 114 and the carbon capture system 134. In other words, the turbine assembly 102 may be operated as a simple gas turbine assembly 102 that uses a cooled interstage air inlet provided via the inlet compressor 174 and the cooler 178. More specifically, in the exemplary embodiment, when the turbine assembly 102 is used as a stand-alone simple cycle gas turbine, the assembly 102 operates with a cooled interstage air inlet without inlet pressurization (at Figure 2 and Figure 3 shown above).

[0027] Operation of the gas turbine assembly 102 as a simple gas turbine facilitates elimination of the need for higher cost rotor alloys or additional cooling air, instead enabling the use of steel compressor wheels, particularly in operating conditions such as hot weather, where compressor outlet air temperatures tend to be highest. Additionally, the physical size and cost of the cooler 178 is relatively modest compared to known power plant systems for cooling the air flow to the gas turbine inlet, since the air flow entering the cooler 178 is lower and the operating temperature of the flow is higher relative to the radiator (ambient). Furthermore, the air intake facilitates power augmentation, since the air intake facilitates reducing the work required of the compressor 106, while still reducing the compressor exhaust discharge temperature.

[0028] Figure 2 It can be used with the combined cycle power generation device 100 ( Figure 1 Schematic diagram of an alternative gas turbine assembly 102 for use with Figure 1 Unlike the embodiment of FIG. 1 (which shows an unpressurized gas turbine assembly 102), in Figure 2 in Figure 2 In the exemplary embodiment of the present invention, the gas turbine assembly 102 utilizes an external inlet boost blower 182. More specifically, in the exemplary embodiment, the external air boost blower 182 pressurizes the air flow 188 that is directed into the inlet 168 of the compressor 106. The boost blower 182 can be used to boost the gas turbine assembly 102 so as to facilitate enhanced or improved gas turbine output. In addition, the combination of the boost blower 182 and the cooled intake air flow 180 supplied to the compressor 106 enables the controller 176 ( Figure 1 ) can provide enhanced control of the discharge temperature of the compressor 106, thereby increasing the power increase potential from the turbine assembly 102.

[0029] Figure 3 It can be used with the combined cycle power generation device 100 ( Figure 1 Schematic diagram of another alternative gas turbine assembly 102 for use with Figure 1 (which shows an unpressurized gas turbine assembly 102) and Figure 2 Unlike the embodiment (which shows an external boost blower), Figure 3 In the exemplary embodiment of the present invention, the gas turbine assembly utilizes a shaft-driven boost compressor 190. More specifically, in the exemplary embodiment, the turbine assembly includes a shaft-driven inlet boost compressor 190 that pressurizes an ambient air flow 194 directed toward the interstage inlet 172 of the compressor 106. Similar to the boost blower 182 ( Figure 2), compressor 190 may be used to boost gas turbine assembly 102. However, compressor 190 is capable of providing increased boost flow to gas turbine assembly 102 compared to boost blower 182. The increased boost helps increase gas turbine output, even exceeding the output of boost blower 182. The combination of compressor 190 and the cooled intake air flow 180 supplied to compressor 106 enables controller 176 ( Figure 1 ) can provide enhanced control of the discharge temperature of the compressor 106, thereby increasing the power increase potential from the turbine assembly 102.

[0030] It should be noted that Figures 1 to 3 Any of the gas turbine assemblies shown in 102 may or may not be used with the carbon capture system 134. Furthermore, in some embodiments, any of the gas turbine assemblies 102 described herein may be used with a recirculated exhaust gas intake, i.e., a compressed aftercooled exhaust gas stream, instead of being used with the compressed aftercooled intake gas stream 180. In such embodiments, the recirculated exhaust gas may be routed from downstream or upstream of the first cooler.

[0031] Figure 4 An alternative combined cycle power plant 100 ( Figure 1 Schematic diagram of ). Figure 4 The implementation shown in is similar to Figure 1 The embodiments shown in , with the differences noted herein below, therefore, Figure 4 The reference numerals used in Figure 1 The same reference numerals are used in Figure 4 In FIG. 1 , the apparatus 100 utilizes an exhaust gas recirculation 402 with the post-combustion carbon capture system 134 . The exhaust gas recirculation flow 402 is extracted from downstream of the first cooler 148 and directed toward an exhaust gas recirculation compressor 404 .

[0032] Cooler 406 is coupled between recirculation compressor 404 and interstage inlet 172. Cooler 406 cools the pressurized air discharged from compressor 404 to define a cooled intake airflow 180. More specifically, cooler 406 discharges cooling flow 180 toward interstage inlet 172 to facilitate improved performance of device 100, as described herein. In the exemplary embodiment, since flow 402 is extracted downstream from cooler 148, the exhaust gas flow has been purified and cooled, and thus facilitates reducing the compression power of recirculation compressor 404, as well as performing the aftercooling required to facilitate control of the compressor discharge temperature.

[0033] In an exemplary embodiment, where compressed aftercooling air is supplied to the interstage inlet 172, the pressurized air flow 180 is clean, and therefore the cooler 406 and the intake compressor 404 can be physically located relatively close to the cooler 148, so as to promote the reduction of the pipe diameter and device cost for the steam 180. In an embodiment of retrofitting an existing device, the compressor 106 can be configured to use the exhaust gas discharged from the compressor 404. In such an embodiment, the assembly 102 not only obtains the above-mentioned benefits, but also obtains those performance benefits generally associated with exhaust gas recirculation, including but not limited to, for example, dirty combustion, higher exhaust carbon dioxide emissions, and lower nitrous oxide emissions. In addition, in an exemplary embodiment, the combination of the operation and pressurization of the gas turbine assembly 102 and the HRSG system 114 helps to overcome the airflow losses through the cooler (i.e., the quench tower 148) and the carbon capture system 134. In other alternative embodiments, according to equipment and device design constraints and economic considerations, a booster fan can be used in the carbon capture system 134.

[0034] Figure 5 is a schematic diagram of another alternative combined cycle power plant 100 including a gas turbine assembly 102 . Figure 6 is a schematic diagram of another alternative combined cycle power plant 100 including a gas turbine assembly 102. Each alternative embodiment is similar to Figure 1 The embodiments shown in , with the differences noted below, therefore, Figure 5 and Figure 6 The reference numerals used in Figure 1 The same reference numerals are used in the drawings.

[0035] exist Figure 5 In the embodiment, the device 100 utilizes exhaust gas recirculation 402 with a post carbon capture system 134. In addition, in Figure 5 In the exemplary embodiment shown, generally the device 100 uses a compressed exhaust gas recirculation intake air directed to the aftercooling of the main gas turbine, combined with exhaust gas recirculation to the gas turbine inlet. More specifically, the exhaust gas recirculation flow 402 is extracted from the downstream of the first cooler 148, and a portion 502 is directed toward the exhaust gas recirculation compressor 404. The cooler 406 is coupled between the recirculation compressor 404 and the interstage inlet 172. The cooler 406 cools the pressurized air discharged from the compressor 404 to define a cooled intake air flow 180. More specifically, the cooler 406 discharges the cooling flow 180 toward the interstage inlet 172 to facilitate improving the performance of the device 100, as described herein.

[0036] The remaining portion 504 of the exhaust gas recirculation flow 402 extracted downstream from the cooler 148 is directed toward the exhaust gas boost blower 506. The boost blower 506 discharges the pressurized and cooled flow 510 toward the compressor inlet 168. In the exemplary embodiment, because the flow 402 is extracted downstream from the cooler 148, the exhaust gas flow has been cleaned and cooled. The combination of the exhaust gas recirculation compressor 404 and the exhaust gas blower 506 helps to maximize the total exhaust gas recirculation flow by using the existing gas turbine within the device 100. More specifically, in Figure 5 In the exemplary embodiment of , because the exhaust boost blower 506 is combined or paired with the inlet air boost blower 182 , the gas turbine compressor 106 may be operated at an inlet pressure greater than ambient or atmospheric pressure, thereby facilitating optimization of plant power output.

[0037] also, Figure 5 The embodiment shown in also enables overcoming any losses associated with the extraction of streams to the carbon capture system 134. More specifically, in Figure 5 In the illustrated plant embodiment, the plant 100 is sufficiently pressurized so that any plant output losses associated with operating the carbon capture system 134 are overcome.

[0038] Figure 6 The implementation shown in is similar to Figure 5 , however, the exhaust gas recirculation compressor is located downstream of the exhaust gas boost blower 506 rather than as Figure 5 506 , the exhaust gas recirculation 502 is extracted before the flow 402 enters the blower 506 . Such an embodiment may facilitate simplifying the exhaust gas recirculation flow control and, therefore, facilitate reducing the overall device cost because the compressor 404 and its associated ducting may be physically located closer to the turbine assembly 102 .

[0039] Embodiments described herein relate to providing cooled ambient air or recirculated exhaust gas intake to the gas turbine compressor intake. Conventional exhaust gas recirculation heats the gas turbine inlet, thereby reducing the density of the working fluid flow entering the compressor, and thus reducing the gas turbine and device output. The cooled interstage intake and control scheme described herein can also be used to limit and / or control the compressor outlet temperature. Therefore, the embodiments described herein facilitate increasing power, reducing the physical size of the exhaust gas recirculation line / pipe, and reducing the gas temperature in the compressor and at the compressor discharge.

[0040] Other aspects of the disclosure are provided by the subject matter of the following clauses:

[0041] 1. A combined cycle power generation device, the combined cycle power generation device comprising: a gas turbine engine, the gas turbine engine comprising a compressor, the compressor having a compressor inlet, a compressor outlet, and an interstage inlet defined between the compressor inlet and the compressor outlet, the gas turbine engine further comprising a turbine outlet, the turbine outlet being configured to discharge a first exhaust gas stream from the turbine outlet; a heat recovery steam generator, the heat recovery steam generator being configured to: receive the first exhaust gas stream in the heat recovery steam generator; extract heat from the first exhaust gas stream; and

[0042] a second exhaust gas stream discharged from the heat recovery steam generator; a recirculation compressor configured to selectively pressurize a first portion of the second exhaust gas stream for recirculation toward the compressor; and a first cooler configured to cool the first portion of the second exhaust gas stream after compression, thereby defining a cooled exhaust gas stream, wherein the first cooler discharges the cooled exhaust gas stream to the interstage inlet of the compressor.

[0043] 2. A combined cycle power generation device according to the preceding clause, further comprising: a steam turbine configured to discharge a steam flow from the steam turbine; a carbon capture system configured to receive the steam flow; and a controller configured to: monitor the power consumption of the recirculation compressor; determine the steam cycle losses caused by directing the steam flow toward the carbon capture system; and adjust the flow rate and temperature of the first portion of the second exhaust gas flow recirculated toward the compressor to facilitate increasing the output of the combined cycle power generation device.

[0044] 3. A combined cycle power generation device according to any of the preceding clauses, further comprising a controller configured to: monitor the temperature of the compressor discharge flow at the compressor outlet; and regulate the flow of cooled exhaust gas provided to the interstage inlet to facilitate maintaining the temperature of the compressor discharge flow within a predetermined temperature range.

[0045] 4. A combined cycle power plant according to any preceding clause, further comprising an exhaust gas recirculation line configured to direct a second portion of the second exhaust gas flow towards the compressor inlet.

[0046] 5. A combined cycle power generation device according to any of the preceding clauses, wherein the combined cycle power generation device also includes a separator, wherein the separator is configured to separate the second exhaust gas flow into the first part, the second part and the third part, and the size of the separator is set to limit the first part to between about 5% and about 10% from the second exhaust gas system, the second part to less than about 40% from the second exhaust gas flow, and the third part to the remainder measured by mass of the second exhaust gas flow.

[0047] 6. A combined cycle power plant according to any preceding clause, further comprising a carbon capture system configured to receive the third portion of the second exhaust gas stream.

[0048] 7. A combined cycle power generation device according to any of the preceding clauses, further comprising a second cooler located between the heat recovery steam generator and the carbon capture system, the second cooler being configured to cool the third portion of the second exhaust gas flow directed toward the carbon capture system.

[0049] 8. A combined cycle power generation device according to any of the preceding clauses, further comprising: an exhaust gas boost blower configured to direct the second exhaust gas flow toward a recirculation compressor; and a separator configured to separate the second exhaust gas flow discharged from the exhaust gas boost blower into the first part directed toward the recirculation compressor and the second part directed toward the compressor inlet.

[0050] 9. A gas turbine assembly, the gas turbine assembly comprising: a gas turbine engine, the gas turbine engine including a compressor, the compressor having a compressor inlet, a compressor outlet and an interstage inlet defined between the compressor inlet and the compressor outlet, the gas turbine engine also including a turbine outlet, the turbine outlet being configured to discharge a first exhaust gas flow from the turbine outlet; an intake compressor, the intake compressor being configured to pressurize one of an exhaust gas flow for recirculation toward the compressor and an ambient air flow directed toward the compressor; a first cooler, the first cooler being configured to cool a compressed flow discharged from the intake compressor, thereby defining a pressurized cooling flow, wherein the first cooler discharges the pressurized cooling flow to the interstage inlet of the compressor.

[0051] 10. The gas turbine assembly according to the preceding clause, further comprising an external inlet boost blower configured to selectively pressurize the ambient air flow before it is discharged towards the compressor inlet.

[0052] 11. A gas turbine assembly according to any preceding clause, further comprising an inlet boost compressor rotatably coupled to the compressor, the inlet boost compressor being configured to pressurize a flow of ambient air discharged towards an inlet of the compressor.

[0053] 12. A combined cycle power generation device according to any of the preceding clauses, further comprising a controller configured to: monitor the temperature of the compressor discharge flow at the compressor outlet; and adjust at least one of the flow rate and temperature of the cooling flow provided to the compressor interstage inlet to facilitate maintaining the temperature of the compressor discharge flow within a predetermined temperature range.

[0054] 13. A gas turbine assembly according to any preceding clause, further comprising one of an external inlet boost blower configured to selectively boost the gas turbine assembly and a shaft-driven inlet boost compressor configured to selectively boost the gas turbine assembly.

[0055] 14. A combined cycle power generation device, the combined cycle power generation device comprising: a gas turbine engine, the gas turbine engine comprising a compressor, the compressor having a compressor inlet, a compressor outlet, and an interstage inlet defined between the compressor inlet and the compressor outlet, the gas turbine engine further comprising a turbine outlet, the turbine outlet being configured to discharge a first exhaust gas stream from the turbine outlet; a heat recovery steam generator, the heat recovery steam generator being configured to: receive the first exhaust gas stream in the heat recovery steam generator; extract heat from the first exhaust gas stream; and

[0056] a second exhaust gas stream discharged from the heat recovery steam generator; at least one of: a recirculation compressor configured to selectively pressurize a first portion of the second exhaust gas stream for recirculation toward the compressor; and an intake compressor configured to pressurize an ambient air flow toward the compressor; and a first cooler configured to cool at least one of the ambient air flow or the first portion of the second exhaust gas stream after compression, thereby defining a cooled exhaust gas stream, wherein the first cooler discharges the cooled exhaust gas stream to the interstage inlet of the compressor.

[0057] 15. A combined cycle power generation device according to the preceding clause, the combined cycle power generation device further comprising: an ambient air flow blower, the ambient air flow blower being configured to pressurize the ambient air flow directed toward the compressor inlet; a steam turbine, the steam turbine being configured to discharge a steam flow from the steam turbine; a carbon capture system, the carbon capture system being configured to receive the steam flow; a controller, the controller being configured to: monitor the power consumption of one of the recirculation compressor and the intake compressor; determine the steam cycle loss caused by discharging the steam flow toward the carbon capture system; and adjust the flow rate of at least one of the first part of the ambient air flow or the second exhaust gas flow directed toward the compressor or the ambient air flow blower to facilitate increasing the output of the combined cycle power generation device, the ambient air flow blower pressurizing the ambient air flow toward the compressor.

[0058] 16. A combined cycle power generation device according to any of the preceding clauses, the combined cycle power generation device also includes a controller configured to: monitor the compressor discharge temperature at the compressor outlet; and adjust at least one of the flow rate and temperature of the cooled recirculated exhaust gas provided to the compressor interstage inlet or the cooled ambient air flow provided to the interstage inlet to facilitate maintaining the compressor discharge temperature within a predetermined temperature range.

[0059] 17. A combined cycle power plant according to any preceding clause, further comprising an exhaust gas recirculation line configured to direct the second exhaust gas flow towards the compressor inlet.

[0060] 18. A combined cycle power plant according to any preceding clause, further comprising a separator configured to separate the second exhaust gas stream into the first portion, the second portion and a third portion, the separator being sized to limit the first portion to about 5% to about 10% of the second exhaust gas stream.

[0061] The second portion is from less than about 40% of the second exhaust gas stream and the third portion is from the remainder, by mass, of the second exhaust gas stream.

[0062] 19. A combined cycle power plant according to any preceding clause, further comprising a carbon capture system configured to receive the third portion of the second exhaust gas stream.

[0063] 20. A combined cycle power plant according to any preceding clause, further comprising a second cooler located upstream of the separator.

[0064] The above description is intended to be exemplary only, and those skilled in the art will recognize that changes may be made to the described embodiments without departing from the scope of the disclosed invention. Modifications falling within the scope of the invention will be apparent to those skilled in the art in view of a review of the present disclosure, and such modifications are intended to fall within the appended claims. The systems and methods described herein are not limited to the specific embodiments described herein, but rather components of the various systems may be utilized independently and separately from other systems and components described herein. For example, a cooled interstage inlet may be implemented and utilized in conjunction with any application where enhanced output is desired.

[0065] Although specific features of various embodiments of the present invention may be shown in some drawings and not in others, this is for convenience only. In addition, reference to "one embodiment" in the above description is not intended to be interpreted as excluding the existence of additional embodiments that also include the described features. In accordance with the principles of the present invention, any feature of a drawing may be referenced and / or claimed in conjunction with any feature of any other drawing.

[0066] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

Claims

1. A combined cycle power generation device (100), comprising: A gas turbine engine (102) comprising a compressor (106) having a compressor inlet (168), a compressor outlet (170), and an interstage inlet (172) defined between the compressor inlet and the compressor outlet, the gas turbine engine (102) further comprising a turbine (110) outlet configured to discharge a first exhaust gas stream (112) therefrom; A heat recovery steam generator (114), the heat recovery steam generator being configured to: receiving the first exhaust gas stream (112) in the heat recovery steam generator; extracting heat from the first exhaust gas stream (112); and discharging a second exhaust gas stream (120) from the heat recovery steam generator; a recirculation compressor (404) configured to selectively pressurize a first portion of the second exhaust gas flow (120) for recirculation toward the compressor (106); and A first cooler (148) configured to cool the first portion of the second exhaust gas stream (120) after compression to define a cooled exhaust gas stream (18), wherein the first cooler (148) discharges the cooled exhaust gas stream (180) to the interstage inlet (172) of the compressor (106).

2. The combined cycle power generation device (100) according to claim 1, further comprising: a steam turbine (104) configured to discharge a steam flow (128) therefrom; a carbon capture system (134) configured to receive the steam flow (128); and A controller (176), the controller being configured to: monitoring power consumption of the recirculation compressor (404); determining steam cycle losses resulting from directing the steam flow (128) toward the carbon capture system (134); and The flow rate and temperature of the first portion of the second exhaust gas stream (120) recirculated toward the compressor (106) are adjusted to facilitate increasing the output of the combined cycle power plant (100).

3. The combined cycle power generation device (100) according to claim 1, further comprising a controller (176), wherein the controller is configured to: monitoring a temperature of a compressor discharge flow at an outlet (170) of the compressor; and A flow rate of cooled exhaust gas (180) provided to the interstage inlet (172) is adjusted to facilitate maintaining the temperature of the compressor discharge stream within a predetermined temperature range.

4. The combined cycle power plant (100) according to claim 1, further comprising an exhaust gas recirculation (402) line configured to direct a second portion of the second exhaust gas flow (120) toward the compressor inlet (168).

5. The combined cycle power generation device (100) according to claim 4 further comprises a separator, wherein the separator is configured to separate the second exhaust gas flow (120) into the first part, the second part and the third part, the size of the separator being set to limit the first part to between about 5% and about 10% from the second exhaust gas system, the second part to less than about 40% from the second exhaust gas flow (120), and the third part to the remaining part measured by mass of the second exhaust gas flow (120).

6. The combined cycle power plant (100) of claim 5, further comprising a carbon capture system (134) configured to receive the third portion of the second exhaust gas stream (120).

7. The combined cycle power generation device (100) according to claim 6, further comprising a second cooler (178) located between the heat recovery steam generator (114) and the carbon capture system (134), the second cooler (178) being configured to cool the third portion of the second exhaust gas flow (120) directed toward the carbon capture system (134).

8. The combined cycle power generation device (100) according to claim 1, further comprising: an exhaust gas boost blower (506) configured to direct the second exhaust gas flow (120) toward a recirculation compressor (404); and A separator configured to separate the second exhaust gas flow (120) discharged from the exhaust gas boost blower (506) into the first portion directed toward the recirculation compressor (404) and the second portion directed toward the compressor inlet (168).

9. A gas turbine assembly (102), comprising: A gas turbine engine (102) comprising a compressor (106) having a compressor inlet (168), a compressor outlet (170), and an interstage inlet (172) defined between the compressor inlet and the compressor outlet, the gas turbine engine (102) further comprising a turbine (110) outlet configured to discharge a first exhaust gas stream (112) therefrom; an intake compressor (174) configured to pressurize one of an exhaust gas flow (402) for recirculation toward the compressor (106) and an ambient air flow (194) directed toward the compressor (106); and A first cooler (148) is configured to cool a compressed flow discharged from the intake compressor (174) to define a pressurized cooling flow (180), wherein the first cooler (148) discharges the pressurized cooling flow (180) to the interstage inlet (172) of the compressor (106).

10. The gas turbine assembly of claim 9, further comprising an external inlet boost blower (182) configured to selectively pressurize an ambient air flow (194) before the air flow (194) is discharged toward the compressor inlet (168).

11. The gas turbine assembly of claim 9, further comprising an inlet boost compressor (190) rotatably coupled to the compressor (106), the inlet boost compressor (190) being configured to pressurize a flow of ambient air (194) discharged toward the compressor inlet (168).

12. The combined cycle power generation device (100) according to claim 9, further comprising a controller (176), wherein the controller is configured to: monitoring a temperature of a compressor discharge flow at an outlet (170) of the compressor; and At least one of a flow rate and a temperature of the cooling stream (180) provided to the compressor interstage inlet (172) is adjusted to facilitate maintaining the temperature of the compressor discharge stream within a predetermined temperature range.

13. The gas turbine assembly of claim 9, further comprising one of an external inlet boost blower (182) configured to selectively boost the gas turbine assembly (102) and a shaft-driven inlet boost compressor (190) configured to selectively boost the gas turbine assembly (102).

14. A combined cycle power generation device (100), comprising: A gas turbine engine (102) comprising a compressor (106) having a compressor inlet (168), a compressor outlet (170), and an interstage inlet (172) defined between the compressor inlet and the compressor outlet, the gas turbine engine (102) further comprising a turbine (110) outlet configured to discharge a first exhaust gas stream (112) therefrom; A heat recovery steam generator (114), the heat recovery steam generator being configured to: receiving the first exhaust gas stream (112) in the heat recovery steam generator; extracting heat from the first exhaust gas stream (112); and discharging a second exhaust gas stream (120) from the heat recovery steam generator; At least one of the following: a recirculation compressor (404) configured to selectively pressurize a first portion of the second exhaust gas flow (120) for recirculation toward the compressor (106); and an intake compressor (174) configured to pressurize a flow of ambient air (194) toward the compressor (106); and A first cooler (148) configured to cool at least one of the ambient air flow (194) or the first portion of the second exhaust gas flow (120) after compression to define a cooled exhaust gas flow (180), wherein the first cooler (148) discharges the cooled exhaust gas flow (180) to the interstage inlet (172) of the compressor (106).

15. The combined cycle power generation device (100) according to claim 14, further comprising: an ambient air flow blower (182) configured to pressurize an ambient air flow (194) directed toward the compressor inlet (168); a steam turbine (104) configured to discharge a steam flow (128) therefrom; a carbon capture system (134) configured to receive the steam flow (128); A controller (176), the controller being configured to: monitoring power consumption of one of the recirculation compressor (404) and the intake compressor (174); determining steam cycle losses resulting from venting the steam stream (128) toward the carbon capture system (134); as well as The flow rate of at least one of the ambient air flow (194) or the first portion of the second exhaust gas flow (120) directed toward the compressor (106) or the ambient air flow blower (182) is adjusted to facilitate increasing the output of the combined cycle power plant (100), the ambient air flow blower pressurizing the ambient air flow (194) toward the compressor (106).

16. The combined cycle power generation device (100) according to claim 14, further comprising a controller (176), wherein the controller is configured to: monitoring a compressor (106) discharge temperature at the compressor outlet (170); and At least one of a flow rate and a temperature of one of the cooled recirculated exhaust gas (180) provided to the compressor interstage inlet (172) or the cooled ambient air flow (194) provided to the interstage inlet (172) is adjusted to facilitate maintaining the compressor discharge temperature within a predetermined temperature range.

17. The combined cycle power plant (100) of claim 14, further comprising an exhaust gas recirculation (402) line configured to direct the second exhaust gas flow (120) toward the compressor inlet (168).

18. The combined cycle power generation device (100) according to claim 17, further comprising a separator, wherein the separator is configured to separate the second exhaust gas flow (120) into the first part, the second part and the third part, the size of the separator being set to limit the first part to be between about 5% and about 10% from the second exhaust gas flow (120), the second part to be less than about 40% from the second exhaust gas flow (120), and the third part to be the remaining part measured by mass of the second exhaust gas flow (120).

19. The combined cycle power plant (100) of claim 18, further comprising a carbon capture system (134) configured to receive the third portion of the second exhaust gas stream (120).

20. The combined cycle power plant (100) according to claim 19, further comprising a second cooler (178) located upstream of the separator.

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