System and method for exhaust gas recirculation and injection in a gas turbine

Abstract

To provide a system and method for exhaust gas recirculation and injection in a gas turbine.SOLUTION: The system includes a gas turbine system having a gas turbine engine including a compressor, a combustor, and a turbine. The gas turbine system further includes an exhaust gas recirculation (EGR) system configured to recirculate a first portion of an exhaust flow from the gas turbine engine to an air intake of the gas turbine engine. The system further includes an exhaust gas injection system including a multistage compressor including a plurality of stages, wherein the multistage compressor is configured to compress a second portion of the exhaust stream. The exhaust gas injection system further includes an intercooler coupled to the multistage compressor. The exhaust gas injection system is configured to inject a second portion of the exhaust stream into the gas turbine engine at one or more exhaust injection locations other than the air intake to provide power augmentation of the gas turbine engine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates generally to systems and methods for exhaust gas recirculation and injection in gas turbine systems. [Background technology]

[0002] Industrial plants, such as combustion-driven power plants, may produce various gases, such as exhaust gases from a combustion system. The combustion system may include a gas turbine engine. These exhaust gases may include one or more undesirable gases, such as carbon-containing gases. Due to various regulations and environmental concerns regarding global warming, it is desirable to reduce the release of undesirable gases into the atmosphere. Unfortunately, exhaust gas treatments, such as gas capture (e.g., carbon capture), can reduce the efficiency and power output of industrial plants. Therefore, there is a need to reduce the undesirable gases while offsetting the efficiency and power output losses associated with exhaust gas treatments. Summary of the Invention

[0003] Certain embodiments commensurate in scope with the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed embodiments; rather, these embodiments are intended only to provide a brief outline of possible forms of the present subject matter. Indeed, the embodiments claimed herein may encompass a variety of forms that may be similar to or different from the embodiments set forth below.

[0004] The system includes a gas turbine system having a gas turbine engine including a compressor, a combustor, and a turbine. The gas turbine system further includes an exhaust gas recirculation (EGR) system configured to recirculate a first portion of an exhaust flow from the gas turbine engine to an intake of the gas turbine engine. The gas turbine system further includes an exhaust gas injection system including a multi-stage compressor including a plurality of stages, the multi-stage compressor configured to compress a second portion of the exhaust flow. The exhaust gas injection system further includes an intercooler coupled to the multi-stage compressor. The exhaust gas injection system is configured to inject the second portion of the exhaust flow into the gas turbine engine at one or more exhaust injection locations to provide power augmentation for the gas turbine engine, the one or more exhaust injection locations being axially spaced from the intake of the gas turbine engine.

[0005] The system includes a controller having a memory, a processor, and instructions stored in the memory and executable by the processor to control a first portion of an exhaust flow from a gas turbine engine through an exhaust gas recirculation (EGR) system to an intake of the gas turbine engine, the gas turbine engine including a compressor, a combustor, and a turbine. The controller is further configured to control a second portion of the exhaust flow from the gas turbine engine through an exhaust gas injection system to one or more exhaust injection locations axially spaced from the intake of the gas turbine engine to provide power augmentation for the gas turbine engine.

[0006] 1. A method comprising: controlling a first portion of an exhaust flow from a gas turbine engine through an exhaust gas recirculation (EGR) system to an intake of the gas turbine engine, the gas turbine engine including a compressor, a combustor, and a turbine. The method further comprises controlling a second portion of the exhaust flow from the gas turbine engine through an exhaust gas injection system to one or more exhaust injection locations, the one or more exhaust injection locations being axially spaced from the intake of the gas turbine engine, to provide power augmentation for the gas turbine engine.

[0007] These and other features, aspects, and advantages of the techniques disclosed herein will be better understood when the following detailed description is read in conjunction with the accompanying drawings, in which like reference numerals represent like parts throughout. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram of an embodiment of a system having a gas turbine system, one or more gas capture systems, and an exhaust gas recirculation (EGR) system. [Figure 2] 2 is a schematic diagram of an embodiment of the system of FIG. 1 further showing an exhaust gas injection system configured to inject exhaust gases from the EGR system into one or more locations on the gas turbine system. [Figure 3] 3 is a flow diagram of an exemplary process for operating the exhaust gas injection system of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0009] One or more specific embodiments of the systems and methods disclosed herein are described below. In an effort to provide a concise description of these embodiments, not all features of an actual implementation are described herein. It should be understood that the development of such an actual implementation, like any engineering or design project, will require numerous implementation-specific decisions to achieve the developer's particular goals, including, for example, compliance with system-related and business-related constraints, which may vary from implementation to implementation. Moreover, it should be understood that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill in the art having the benefit of this disclosure.

[0010] When introducing elements of various embodiments of the presently disclosed embodiments, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0011] Embodiments of the present disclosure include systems and methods for improving the power output and efficiency of a gas turbine system by injecting a portion of the exhaust gas from an EGR system of the gas turbine system into a compressor discharge casing of a gas turbine engine of the gas turbine system. Prior to injection into the compressor discharge casing, the portion of the exhaust gas is compressed through a compressor powered by a reciprocating engine. In certain embodiments, the compressor is a multi-stage compressor having multiple compression stages with intercoolers between the compression stages. Additionally, the reciprocating engine may provide waste heat to thermally regulate the temperature of the exhaust gas injected into the compressor discharge casing. The injected exhaust gas can help improve the efficiency and power output of the gas turbine system. In systems with a gas capture system (e.g., a carbon capture system), the improved efficiency and power output achieved by the injected exhaust gas helps offset efficiency and power losses associated with the gas capture system. Various aspects of the EGR system and exhaust injection are described in further detail below.

[0012] 1 is a block diagram of an embodiment of a system 10 including a gas turbine system 12 (e.g., a gas turbine engine), a steam turbine system 14, a heat recovery steam generator (HRSG) 16, a gas processing system 18 having one or more gas capture systems 20, and a controller 22 coupled to each of the systems 12, 14, 16, and 18. As described below, the one or more gas capture systems 20 of the gas processing system 18 are configured to capture undesirable gases (e.g., CO) from exhaust gases and / or air (e.g., via direct or indirect air capture). In the illustrated embodiment, the system 10 is a combined cycle system including the gas turbine system 12, the steam turbine system 14, and the HRSG 16. However, in some embodiments, the system 10 may be a simple cycle system including the gas turbine system 12 without the steam turbine system 14 and the HRSG 16. In either case, the system 10 includes a gas treatment system 18 having one or more gas capture systems 20 and an exhaust gas recirculation (EGR) system 60 having exhaust injection at various exhaust injection locations 59. The exhaust injection helps to improve the efficiency and power output of the gas turbine system 12, thereby helping to offset efficiency and power losses associated with the one or more gas capture systems 20.

[0013] Before describing the details of the gas processing system 18, various aspects of the system 10 will be described in more detail. For purposes of direction in the drawings, reference may be made to an axial direction or axis 40, a radial direction or axis 42 extending radially away from the axial direction or axis 40, and a circumferential direction or axis 44 extending circumferentially around the axial direction or axis 40. The directions or axes 40, 42, and 44 may be referenced to the axis of rotation of the gas turbine system 12, for example.

[0014] The gas turbine system 12 includes an air intake 50, a compressor 52 having one or more compressor stages, one or more combustors 54, a compressor discharge casing 55, a turbine 56 (e.g., an expansion turbine) having one or more turbine stages, and a load 58 (e.g., a generator) driven by the turbine 56. As described above, the gas turbine system 12 includes an EGR system 60 configured to recirculate exhaust gases 61 to the air intake 50. In certain embodiments, the EGR system 60 includes one or more cooling and scrubbing modules 63 configured to receive the exhaust gases 61 from the gas turbine system 12 and / or the HRSG 16. The cooling and scrubbing module 60 may include one or more condensers and / or one or more filters configured to cool and scrub the exhaust gases 61 received from the gas turbine system 12 and / or the HRSG 16. The recirculated exhaust gas 61 serves to reduce the temperature of the exhaust gas 61 and to reduce certain emissions associated with combustion in the combustor 54, such as nitrogen oxides (NO X During operation, the compressor 52 receives air from the intake 50 (and exhaust gases 61 if the EGR system 60 is activated) and compresses the air and / or exhaust gases 61 in one or more compressor stages (e.g., stages of rotating compressor blades). The compressed air travels from the last compressor stage through a compressor diffuser and into a compressor discharge casing 55, which surrounds at least a downstream portion of the combustor 54. The combustor 54 includes one or more fuel nozzles (or burners) that generate hot combustion gases by combusting fuel from a fuel supply system with compressed air and / or exhaust gases (i.e., fluid from the compressor discharge casing 55 that may have previously been used to cool the combustor 54). The hot combustion gases expand and drive one or more turbine stages (e.g., stages of rotating turbine blades) in the turbine 56, which in turn drives the rotation of the compressor 52 and a load 58 via a shaft. Turbine 56 then outputs the energy-depleted combustion gases as exhaust gases 61 .

[0015] In the combined cycle configuration of system 10, HRSG 16 recovers waste heat from exhaust gas 61 and generates steam to drive steam turbine system 14. HRSG 16 includes an HP steam section 70, an IP steam section 72, and an LP steam section 74 configured to generate high-pressure (HP) steam 76, intermediate-pressure (IP) steam 78, and low-pressure (LP) steam 80. Steam turbine system 14 may include an HP steam turbine 82 driven by HP steam 76, an IP steam turbine 84 driven by IP steam 78, and an LP steam turbine 86 driven by LP steam 80. In addition to the steam provided by HRSG 16, HP steam turbine 82 supplies IP steam to IP steam turbine 84, which supplies LP steam to LP steam turbine 86. LP steam turbine 86 then outputs the remaining steam / water to a condensate line 88 coupled to LP steam section 74 of HRSG 16. The condensate line 88 may include a condenser 90 configured to condense the remaining steam to form a condensate, and a pump 92 configured to pump the condensate back to the LP steam section 74. During operation, the steam turbine system 14 drives a load 94 (e.g., a generator) via a shaft.

[0016] In certain embodiments, the steam turbine system 14 and / or the HRSG 16 may supply heated water and / or steam (e.g., HP steam 76, IP steam 78, and / or LP steam 80) to the gas processing system 18 to support the desorption mode of one or more gas capture systems 20. For example, the gas capture system 20 may accept heated water and / or steam at a temperature range of 100-150 degrees Celsius, 110-150 degrees Celsius, 120-150 degrees Celsius, or 130-150 degrees Celsius. In a simple cycle configuration of the system 10, the steam turbine system 14 and the HRSG 16 are excluded from the system 10.

[0017] Exhaust gases 61 flow from the gas turbine system 12 and / or the HRSG 16 to an EGR system 60 having a cooling and cleaning module 63. In the illustrated embodiment, the EGR system 60 is configured to control the flow of the exhaust gases 61 through an exhaust gas circuit 118 (e.g., fluid conduits and a manifold) having a valve 128, the exhaust gas circuit 118 including an exhaust gas circuit 130 extending to the intake 50, an exhaust gas circuit 132 extending through the exhaust gas injection system 97 to one or more exhaust injection locations 59 downstream of the compressor 52 (e.g., the compressor discharge casing 55, the combustor 54, and / or the turbine 56), and an exhaust gas circuit 134 extending to the gas treatment system 18. The exhaust gas circuit 130 includes valves 128, 131 configured to selectively control the amount or percentage of exhaust gases 61 (e.g., the intake portion 95) that are directed to the intake 50. The exhaust gas circuit 132 includes valves 128, 133 configured to selectively control the amount or percentage of the exhaust gases 61 (e.g., injection portion 99) that is directed through the exhaust gas injection system 97 to one or more exhaust injection locations 59. The exhaust gas circuit 134 includes valves 128, 135 configured to selectively control the amount or percentage of the exhaust gases 61 (e.g., gas trap portion 107) that is directed to the gas treatment system 18. As shown, the exhaust gas circuit 130 routes the inlet portion 95 of the exhaust gases 61 to the inlet 50 of the gas turbine system 12. In certain embodiments, a fan or blower may aid in forcing the flow of the exhaust gases 61 from the inlet portion 95 to the inlet 50.

[0018] In the illustrated embodiment, the exhaust gas circuit 132 routes an injected portion 99 (e.g., a partial extraction) of the exhaust gas 61 to an exhaust gas injection system 97. As shown, the exhaust gas injection system 97 includes an exhaust gas compressor, such as a multi-stage compressor 93 having a plurality of stages 98. The plurality of stages 98 is configured to compress the injected portion 99 of the exhaust gas 61 in the compression stages. The multi-stage compressor 93 is configured to receive the injected portion 99 of the exhaust gas 61 from the EGR system 60. The exhaust gas injection system 97 also includes an intercooler 101 fluidly coupled to each of the plurality of stages 98 of the multi-stage compressor 93. The intercooler 101 is configured to cool the injected portion 99 of the exhaust gas 61 between the stages 98 of compression by the multi-stage compressor 93. As shown, the exhaust gas injection system 97 also includes an engine 103 (e.g., a reciprocating piston-cylinder engine) configured to drive the multi-stage compressor 93. The engine 103 may include 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 piston-cylinder assemblies powered by combustion of a fuel such as natural gas, diesel, gasoline, or biofuel.

[0019] Additionally, the exhaust gas injection system 97 includes one or more valves 105 configured to adjust a proportion (e.g., amount) of the injection portion 99 of the exhaust gases 61 through the exhaust gas circuit 132 to various exhaust injection locations 59 (e.g., the compressor discharge casing 55, the combustor 54, and the turbine 56 of the gas turbine system 12). Each of the exhaust injection locations 59 is generally downstream of compression (e.g., a compression stage of the compressor blades) of the compressor 52. During operation, the injection portion 99 of the exhaust gases 61 is configured to increase or augment the power of the gas turbine system 12, such as by providing additional fluid energy (i.e., additional mass flow) to drive the turbine 56. The exhaust gases 61 delivered to the compressor discharge casing 55 may be used to cool the combustor 54 or may then be directed to fuel nozzles to participate in the combustion of fuel to generate additional combustion gases. Alternatively, or additionally, the exhaust gas 61 supplied to the combustor 54 may be supplied directly to the fuel nozzle for introduction into the combustor 54 (e.g., used as a diluent or as a barrier fluid between the fuel flow and the air flow).

[0020] In certain embodiments, the exhaust gas injection system 97 includes a heat exchanger 109 for selectively transferring heat (e.g., heating or cooling) with the injection portions 99 of the exhaust gases 61 through the exhaust gas circuit 132 to the various exhaust injection locations 59 such that the temperature of the injection portions 99 may be controlled to approximately match the temperature of the exhaust injection locations 59. For example, the heat exchanger 109 may be configured to transfer heat between the engine 103 and the injection portions 99, such as by circulating a heat transfer medium (e.g., lubricant, coolant, water, etc.) between the engine 103 and the heat exchanger 109.

[0021] In the illustrated embodiment, the exhaust gas circuit 134 and valve 135 selectively route the gas-trapped portion 107 of the exhaust gas 61 through one or more gas trapping systems 20 configured to trap undesired gases. The undesired gases include carbon oxides (CO X ) (e.g., carbon dioxide (CO2) and carbon monoxide (CO)), nitrogen oxides (NO X) (e.g., nitrogen dioxide (NO2)), sulfur oxides (SO X ) (e.g., sulfur dioxide (SO2)), or any combination thereof. In the following description, CO2 may be used as an example of an undesired gas, but gas capture system 20 may be designed to capture any of the aforementioned undesired gases. For example, gas capture system 20 includes one or more carbon capture systems 100 (e.g., CO2 capture systems). Gas capture system 20 (e.g., carbon capture system 100) may include a sorbent-based gas capture system, a solvent-based gas capture system, a cryogenic gas capture system, or any combination thereof configured to remove and capture undesired gases. Carbon capture system 100 may include components 102, 104, 106, and 108 configured to enable gas capture of undesired gases (e.g., CO2) from exhaust gas 61, thereby outputting process gas 110 and captured gas 112 (e.g., CO2). Process gas 110 may be substantially free of undesired gases (e.g., CO2) and may be discharged through an exhaust stack. The captured gas 112 (e.g., CO2) may be compressed by a compression system 114 and stored and / or transported by a storage and / or pipeline system 116.

[0022] In certain embodiments, carbon capture system 100 is a sorbent-based carbon capture system, and components 102, 104, 106, and / or 108 include multiple sorbent-based carbon capture units (e.g., adsorber). For example, the sorbent-based carbon capture units may include temperature swing adsorption (TSA) units or adsorber, which use temperature swings or temperature changes to operate sequentially in adsorption, desorption, and cooling modes at various temperatures. In the adsorption mode, the adsorber is configured to adsorb undesired gases (e.g., CO) onto the adsorbent material at a first temperature. In the desorption mode, the adsorber is configured to desorb undesired gases (e.g., CO) from the adsorbent material, for example, by heating the adsorbent material from a first temperature to a second, higher temperature using a heat source. The heat source may include a heated fluid, such as a heated gas and / or a liquid (e.g., steam). In the cooling mode, the adsorber is cooled in preparation for the next adsorption mode.

[0023] In certain embodiments, carbon capture system 100 is a solvent-based carbon capture system, and components 102, 104, 106, and / or 108 include one or more absorbers, strippers, and associated equipment. For example, the absorber is configured to absorb undesired gases (e.g., CO) into a solvent, thereby passing treated gas 110 through an exhaust stack and outputting a CO2-rich solvent to the stripper. The stripper is configured to apply heat to the CO2-rich solvent, thereby stripping the undesired gases (e.g., CO2) from the solvent to produce captured gas 112 and a CO2-lean solvent. The stripper may receive heat via a heat source, such as a heated gas and / or liquid (e.g., steam). The stripper returns the CO2-lean solvent to the absorber to repeat the cycle.

[0024] In the illustrated embodiment, the controller 22 is configured to control all aspects of the system 10. The controller 22 includes one or more processors 120, a memory 122, instructions 124 stored in the memory 122 and executable by the processor 120, and communication circuitry 126 configured to communicate with sensors and various devices of the system 10. For example, the controller 22 is configured to receive sensor feedback from sensors coupled to the gas turbine system 12, the steam turbine system 14, the HRSG 16, and the gas processing system 18 (e.g., the gas capture system 20) and control those devices based on the sensor feedback, an operating mode, a user input, a computer model, or any combination thereof. The sensors (e.g., sensors 180, 182 in FIG. 2 ) may include temperature sensors, pressure sensors, flow sensors, gas composition sensors, or any combination thereof. In certain embodiments, the controller 22 is configured to control the operation of the gas capture system 20 (e.g., the carbon capture system 100), such as by controlling a mode of operation (e.g., an adsorption mode, a desorption mode, and a cooling mode), by controlling a heat source for supplying a heated fluid (e.g., a vapor) to the gas capture system 20, by controlling a cooling source for supplying a cooled fluid to the gas capture system 20, or any combination thereof.

[0025] In certain embodiments, controller 22 may be configured to control flow through each of exhaust gas circuits 118 (e.g., 130, 132, and 134), such as by controlling valves 128 (e.g., 131, 133, and 135) and valve 105, to selectively vary (e.g., increase or decrease) exhaust flow to intake 50, exhaust injection locations 59 (e.g., compressor discharge casing 55, combustor 54, and turbine 56), and gas processing system 18. Collectively, valves 128 (e.g., 131, 133, and 135) and valve 105 may be identified as valve 136, which may include a passive valve (e.g., a check valve responsive to a pressure differential), an active valve (e.g., an actuator-controlled valve responsive to control by controller 22), or any combination thereof. Additionally, the controller 22 may be configured to control one or more components of the exhaust gas injection system 97, such as the multi-stage compressor 93, the intercooler 101, the engine 103, the valves 105, and the heat exchanger 109.

[0026] In certain embodiments, the controller 22 is configured to cooperatively control the EGR system 60, the exhaust gas injection system 97, the gas turbine system 12, and the gas processing system 18 (e.g., the carbon capture system 100) based on sensor feedback indicative of the operating conditions and / or load of the gas turbine system 12, the power demand by the gas processing system 18 (e.g., the carbon capture system 100), the sensed exhaust emissions versus a threshold, or any combination thereof. For example, the load of the gas turbine system 12 may include a part-load condition or a full-load condition, and the load may include a load for driving a generator or other equipment, a power demand on the power grid, a power demand by the gas processing system 18 (e.g., the carbon capture system 100), or any combination thereof. The operating conditions of the gas turbine system 12 may include a transient condition (e.g., a start-up condition, a shutdown condition, or a variable demand condition), a steady-state condition, or any combination thereof. In a further example, the power demand by the gas processing system 18 (e.g., carbon capture system 100) may vary depending on the concentration of undesirable gases (e.g., CO) in the exhaust gas, the flow rate of the exhaust gas, the fuel composition (e.g., dirty fuel vs. clean fuel) used in the gas turbine system 12, the target level (e.g., percentage) of carbon capture, the number of stages of carbon capture, or any combination thereof. Similarly, the sensed emissions may vary depending on the concentration of undesirable gases (e.g., CO) in the exhaust gas, the flow rate of the exhaust gas, the fuel composition (e.g., dirty fuel vs. clean fuel) used in the gas turbine system 12, the target level (e.g., percentage) of carbon capture, the number of stages of carbon capture, or any combination thereof. X (CO and / or CO2), NO X , SO X The detected emissions may include detected emission levels of undesirable gases such as, for example, , , or any combination thereof, and the detected emissions are compared to threshold values ​​based on regulatory requirements, gas turbine controls, and controls by the gas processing system 18.

[0027] During operation, the controller 22 adjusts the emissions controls (e.g., NO XThe controller 22 may vary the flow of exhaust gas 61 through the intake 50 for power augmentation (e.g., exhaust gas injection system 97 to one or more exhaust injection locations 59 for power augmentation), and through the exhaust gas treatment system 18 (e.g., carbon capture system 100) for emissions control and carbon capture. In certain embodiments, the controller 22 is configured to increase the flow of exhaust gas 61 through the exhaust gas injection system 97 to one or more exhaust injection locations 59 to increase the power augmentation and offset an increase in power demand by the exhaust gas treatment system 18 (e.g., carbon capture system 100), and the controller 22 is configured to decrease the flow of exhaust gas 61 through the exhaust gas injection system 97 to one or more exhaust injection locations 59 to decrease the power augmentation in response to a decrease in power demand by the exhaust gas treatment system 18 (e.g., carbon capture system 100). Additionally, the controller 22 may be configured to increase or decrease the flow of exhaust gas 61 through the exhaust gas treatment system 18 (e.g., carbon capture system 100) to increase or decrease the amount of carbon capture. Thus, the controller 22 is configured to cooperatively control the emission levels, the amount of carbon capture, and the output to the power grid.

[0028] 2 is a schematic diagram of one embodiment of the system 10, further illustrating features of the exhaust gas injection system 97 of the EGR system 60. In the illustrated embodiment, the EGR system 60 recirculates at least a portion of the exhaust gas 61 generated by the gas turbine system 12, and the EGR system 60 may receive the exhaust gas 61 directly from the gas turbine system 12 and / or indirectly via the HRSG 16. The EGR system 60 cools and cleans the exhaust gas 61 via a cooling and cleaning module 63. The EGR system 60 selectively routes the exhaust gas 61 through an exhaust gas circuit 118 (e.g., 130, 132, and 134) to the intake 50, the exhaust gas injection system 97, or the gas treatment system 18 having a carbon capture system 100, such as by controlling valves 131, 133, and 135 via the controller 22. In certain embodiments, a majority of the exhaust gas 61 is diverted to the gas treatment system 18. For example, 60%, 65%, 70%, 75%, 80%, or more than 85% of the exhaust gas 61 (e.g., gas trapping portion 107) may be diverted along exhaust gas circuit 134 to gas treatment system 18.

[0029] As shown, the remaining portion 140 of the exhaust gases 61 is diverted to the inlet 50 of the gas turbine system 12 (e.g., inlet portion 95) via the exhaust gas circuit 130 or to the exhaust gas injection system 97 (e.g., injection portion 99) via the exhaust gas circuit 132. In certain embodiments, the injection portion 99 of the remaining portion 140 of the exhaust gases 61 may comprise less than 15, 12, 9, 6, or 3% of the remaining portion 140 of the exhaust gases 61. That is, a majority of the remaining portion 140 is fed back to the inlet 50 of the gas turbine system 12. However, any suitable percentage or proportion of the exhaust gases 61 may be routed through the exhaust gas circuit 118 (e.g., 130, 132, and 134) to the inlet 50, the exhaust gas injection system 97, or the gas treatment system 18. Additionally, any suitable proportion or ratio of the exhaust gases 61 may be routed through exhaust gas circuits 118, 132 with exhaust gas injection system 97 to one or more of the exhaust injection locations 59 downstream of the compressor 52 (e.g., compressor discharge casing 55, combustor 54, and / or turbine 56). The aforementioned exhaust gas proportions or ratios may be achieved with valves 128 (e.g., 131, 133, and 135) and valve 105.

[0030] As shown, the exhaust gas injection system 97 includes a multi-stage compressor 93 having multiple stages 98 (e.g., stages 142, 144, and 146). While the illustrated embodiment shows the multi-stage compressor 93 having three stages 98, it should be appreciated that the multi-stage compressor 93 may include two or more stages 98. For example, the multi-stage compressor 93 may include two, four, five, six, seven, eight, or more stages 98. The multi-stage compressor 93 is driven by an engine 103 (e.g., a reciprocating piston-cylinder engine) that receives air 148 and fuel 150 (e.g., natural gas, diesel fuel, biofuel, gasoline, etc.) and produces engine exhaust gas 152. It can be appreciated that the multi-stage compressor 93 is configured to compress the exhaust gas 61 to produce compressed exhaust gas 156 having a pressure that substantially matches the pressure of an exhaust injection location 59, such as the compressor discharge casing 55 of the gas turbine system 12.

[0031] The exhaust gas injection system 97 also includes an intercooler 101. In the illustrated embodiment, the intercooler 101 is fluidly coupled to multiple stages 98 of the multi-stage compressor 93. As shown, the intercooler 101 is bidirectionally fluidly coupled to stages 142 and 144 and unidirectionally fluidly coupled to stage 146 such that exhaust gases 61 flow from the intercooler 101 to stage 146. In certain embodiments, both the first stage (e.g., stage 142) and the last stage (e.g., stage 146) of the multi-stage compressor 93 may be unidirectionally fluidly coupled to the intercooler 101. In certain embodiments, the intercooler 101 may be fluidly coupled to any combination of the stages 98 of the multi-stage compressor 93. As shown, the intercooler 101 may receive a coolant 153 (e.g., water) from an external coolant source.

[0032] In the illustrated embodiment, the exhaust gas injection system 97 also includes at least one heat exchanger 109, such as a heat exchanger 154 (e.g., a waste heat recovery system, heat exchanger, or recuperator). The heat exchanger 154 is fluidly coupled to the multi-stage compressor 93 and the engine 103 and configured to receive the compressed exhaust gas 156 output by the multi-stage compressor 93 and the engine exhaust gas 152 output by the engine 103. The heat exchanger 154 is configured to transfer heat from the engine exhaust gas 152 to the compressed exhaust gas 156. After passing through the heat exchanger 154, the compressed exhaust gas 156 may be injected into the compressor discharge casing 55 of the gas turbine system 12. In certain embodiments, the heat exchanger 154 may be configured to heat the compressed exhaust gas 156 until the temperature of the compressed exhaust gas 156 substantially matches (e.g., within ±5°C, 10°C, 15°C, 20°C, or 25°C) the temperature of the high-pressure air in the compressor discharge casing 55. In certain embodiments, after the engine exhaust gases 152 pass through the heat exchanger 154, the engine exhaust gases 152 may be vented to the atmosphere.

[0033] In certain embodiments, the exhaust gas injection system 97 includes a turbocharger 158. In certain embodiments, the engine 103 is fluidly coupled to the turbocharger 158 such that engine exhaust gases 152 are channeled from the engine 103 to the turbocharger 158, thereby at least partially powering the turbocharger 158. The turbocharger 158 may include a turbine driven by the engine exhaust gases 152. The turbocharger 158 may also include a compressor driven by the turbine that compresses air 148 received by the engine 103. In the illustrated embodiment, the engine 103 is fluidly coupled to the HRSG 16 such that the engine exhaust gases 152 are received by the HRSG 16 from the engine 103. In certain embodiments, the engine 103 may be fluidly coupled to the compressor discharge casing 55 such that the engine exhaust gases 152 are injected into the compressor discharge casing 55. In certain embodiments, the engine exhaust gases 152 may be directed to the HRSG 16, the compressor discharge casing 55, a turbocharger 158, or a combination thereof.

[0034] In the illustrated embodiment, the exhaust gas injection system 97 is configured to inject the compressed exhaust gas 156 (e.g., injection portion 99) from the EGR system 60 to one or more exhaust injection locations 59 of the gas turbine system 12. As shown, the heat exchanger 154 may be fluidly coupled to the compressor discharge casing 55 and / or a last stage portion 160 of the compressor 52 of the gas turbine system 12 (e.g., downstream of compression by the compressor blades of the compressor 52). In certain embodiments, the compressed exhaust gas 156 may be channeled from the heat exchanger 154 to the last stage portion 160 of the compressor 52, the compressor discharge casing 55, or a combination.

[0035] Additionally or alternatively, the exhaust gas injection system 97 may be configured to inject a turbine portion 161 of the exhaust gases 61 into a turbine 56 (e.g., an expansion turbine) of the gas turbine system. The exhaust gas injection system 97 may be fluidly coupled to one or more exhaust injection locations 59 (e.g., turbine location 162) through an outer casing 164 of the turbine 56 and into an exhaust flow path through the turbine 56. As shown, the final stage 146 of the multi-stage compressor 93 is fluidly coupled to a first axial location 165 of the one or more turbine locations 162, and the middle stage 144 of the multi-stage compressor 93 is fluidly coupled to a second axial location 166 of the one or more turbine locations 162. The first axial location 165 and the second axial location 166 are different from one another. That is, the first axial location 165 and the second axial location 166 have different positions along the axial direction 40. As shown, the first axial location 165 is upstream (i.e., forward) of the second axial location 166. The turbine portion 161 of the exhaust gases 61 may include an upstream portion 168 that is injected from a stage 146 of the multi-stage compressor 93 to the first axial location 165 of the turbine 56. Additionally, the turbine portion 161 of the exhaust gases 61 may include a downstream portion 170 that is injected from a stage 144 of the multi-stage compressor 93 to the second axial location 166 of the turbine 56. It will be appreciated that the stages 98 of the multi-stage compressor 93 compress the exhaust gases 61 in discrete stages (e.g., steps), thereby enabling the pressure of the exhaust gases 61 at each stage 68 to substantially match the pressure of the air flowing through the gas turbine system 12.

[0036] While the illustrated embodiment shows two stages 98 of the multi-stage compressor 93 fluidly coupled to two turbine locations 162 of the turbine 56 of the gas turbine system 12, it should be understood that fewer or more stages 98 of the multi-stage compressor 93 may be fluidly coupled to the turbine 56. For example, one stage of the multi-stage compressor 93 may be fluidly coupled to the turbine 56. In another example, an extract from one or more stages of a multi-stage compressor 93 having three, four, five, six, seven, eight, or more stages 98 may be fluidly coupled to one or more stages of the turbine 56. Additionally or alternatively, the coupling of the stages 98 of the multi-stage compressor 93 to the turbine 56 may be combined with the coupling of the heat exchanger 154 to the compressor 52 and / or the compressor discharge casing 55.

[0037] In the illustrated embodiment, the EGR system 60 and / or the exhaust gas injection system 97 include one or more valves 136, including valves 128 (e.g., 131, 133, and 135) and valves 105 (e.g., valves 172, 174, 176, 178, 179, and 181). The controller 22 may be communicatively coupled to any combination of the one or more valves 136. As shown, the valve 172 is disposed between the heat exchanger 154 and the engine 103. The valve 172 may be configured to regulate the flow of engine exhaust gases 152 from the engine 103 to the heat exchanger 154, thereby regulating the amount of heat transfer from the engine exhaust gases 152 to the compressed exhaust gases 156 in the heat exchanger 154.

[0038] As shown, the one or more valves 105 also include a valve 174 disposed between the heat exchanger 154 and the intercooler 101 such that the heat exchanger 154 is fluidly coupled to the intercooler 101. Additionally, the valve 174 may be fluidly coupled to the engine 103 and configured to adjust the flow rate of engine exhaust gases 152 discharged by the heat exchanger 154 that enters the intercooler 101. In certain embodiments, the valve 174 may be configured to receive a signal from the controller 22 to adjust the proportion of engine exhaust gases 152 entering the intercooler 101 relative to ventilation with air (venting not shown in FIG. 2 ).

[0039] Additionally, an exhaust gas circuit 175 extends between the heat exchanger 154 and the gas turbine 12. Specifically, the one or more valves 105 described above may include a valve 176 disposed along the exhaust gas circuit 175 between the heat exchanger 154 and a final stage of the compressor 52 (i.e., feeding the compressor discharge casing 55), and a valve 178 disposed along an exhaust gas circuit 177 between the heat exchanger 154 and the combustor 54 (e.g., directing the compressed exhaust gas 156 to the fuel nozzles), which may be fluidly coupled to the exhaust gas circuit 175. In certain embodiments, the valve 176 may be configured to receive a signal from the controller 22 to adjust the flow rate of the compressed exhaust gas 156 injected from the heat exchanger 154 into the compressor discharge casing 55. Similarly, the valve 178 may be configured to receive a signal from the controller 22 to adjust the flow rate of the compressed exhaust gas 156 injected from the heat exchanger 154 into the combustor 54. For example, in certain embodiments, the controller 22 may command the valves 176 and / or 178 to reduce the flow of compressed exhaust gas 156 to the compressor discharge casing 55 and / or combustor 54 when the turbine 56 is operating at part load.

[0040] Additionally, a valve 133 is disposed between the EGR system 60 and the multi-stage compressor 93. The valve 133 may be configured to receive a signal from the controller 22 to control the proportion of the remaining portion 140 of the exhaust gas 61 (e.g., the injected portion 99) that is diverted to the exhaust gas injection system 97. For example, the controller 22 may be configured to instruct the valve 133 to reduce the proportion of the injected portion 99 in response to detecting that the turbine 56 is operating at part load or has stopped operating. In certain embodiments, the controller 22 may instruct the valve 133 to stop extracting the injected portion 99 from the exhaust gas 61 discharged from the EGR system 60 in response to the turbine 56 operating at part load. It should be appreciated that the EGR system 60 can continue to operate regardless of whether the turbine 56 is operating at part load or full load.

[0041] Additionally, the one or more valves 105 may include valves 179 and 181 that separately control the flow of the injection portion 99 of the exhaust gases 61 from the multi-stage compressor 93 to the turbine 56. That is, the valve 179 may be communicatively coupled to the controller 22 and configured to adjust the flow of the exhaust gases 61 from the final stage 146 of the multi-stage compressor 93 to the first axial location 165 of the turbine 56. Additionally, or alternatively, the valve 181 may be communicatively coupled to the controller 22 and configured to adjust the flow of the exhaust gases 61 from the middle stage 144 of the multi-stage compressor 93 to the second axial location 166 of the turbine 56. The controller 22 may be configured to control the valves 179 and 181 synchronously (e.g., together) or separately in certain embodiments.

[0042] It may be appreciated that exhaust gas injection system 97 may include a combination of one or more valves 105 in combination with valves 128 (e.g., 131, 133, and 135). Additionally, in certain embodiments, one or more valves 105 may include valves located at other locations throughout exhaust gas injection system 97. In certain embodiments, at least one of one or more valves 105 may include a redundant valve and / or a check valve in case of blockage.

[0043] In certain embodiments, the controller 22 may be configured to control a combination of the plurality of valves 136 (e.g., 105 and 128) based on one or more operating conditions of the system 10. For example, the controller 22 may be configured to receive a signal indicative of a load of the gas turbine system 12. In certain embodiments, the controller 22 may be configured to receive a signal from a sensor 180 configured to output a signal indicative of a load of the gas turbine system 12. The controller 22 may then determine an estimated load of the gas turbine system 12 based on the signal. For example, the controller 22 may be configured to determine whether the gas turbine system 12 is operating at a partial load or a full load based on the received signal. The controller 22 may be configured to compare the estimated load of the gas turbine system 12 to a threshold load. For example, the threshold load may be a percentage of a full load of the gas turbine system 12. Based on the comparison result, the controller 22 may be configured to control a combination of the plurality of valves 136 (e.g., 105 and 128). For example, the controller 22 may be configured to control the valve 133 to divert the injection portion 99 of the exhaust gas 61 to the multi-stage compressor 93 in response to the estimated load of the gas turbine system 12 exceeding a threshold load.

[0044] In certain embodiments, the controller 22 may be configured to adjust at least one of the one or more valves 105 to adjust the temperature of the injection portion 99 of the exhaust gases 61. For example, the controller 22 may be configured to receive a signal indicative of the temperature of the injection portion 99 of the exhaust gases 61 from the sensor 182. The controller 22 may then determine an estimated temperature of the injection portion 99 of the exhaust gases 61 based on the signal. The controller 22 may be configured to compare the estimated temperature of the injection portion 99 to a threshold temperature. Based on the comparison, the controller 22 may be configured to control a combination of the plurality of valves 105. For example, the controller 22 may be configured to control the valve 172 to adjust the amount of engine exhaust gases 152 that the heat exchanger 154 accepts, thereby adjusting the amount that the compressed exhaust gases 156 are heated before being injected into the compressor discharge casing 55. In certain embodiments, the controller 22 may be configured to control the valve 174 to adjust the amount of engine exhaust gas 152 that the intercooler 101 accepts, thereby adjusting the amount that the compressed exhaust gas 156 is cooled while flowing through the multi-stage compressor 93 and the intercooler 101. In certain embodiments, the controller 22 may be configured to control a combination of the valves 172 and 174 to adjust the temperature of the injection portion 99. Additionally or alternatively, the controller 22 may be configured to control a combination of the valves 133, 176, 178 to adjust the amount of exhaust gas 61 that is injected into the compressor discharge casing 55 and the combustor 54.

[0045] 3 is a flow diagram of an exemplary process 200 for operating the exhaust gas injection system 97 of the EGR system 60. The process 200 may be performed by a computing device or controller disclosed above with reference to FIGS. 1 and 2, or any other suitable computing device or controller. Furthermore, the blocks of the process 200 may be performed in the order disclosed herein or in any other suitable order. For example, certain blocks of the process 200 may be performed simultaneously. Additionally, in certain embodiments, at least one of the blocks of the process 200 may be omitted.

[0046] In block 202 of process 200, a processor (e.g., a controller) receives a signal indicative of a load on a gas turbine engine of gas turbine system 12. For example, the processor may receive a signal from a sensor, the signal indicative of the load on the gas turbine engine. The sensor may include an encoder, a torque sensor, an oxygen sensor, a fuel flow meter, or a combination thereof.

[0047] At block 204 of process 200, the processor determines an estimated load of gas turbine engine 12 based on the signal. In certain embodiments, the load of gas turbine engine 12 may be determined by comparing the flow rate of fuel at a given speed of gas turbine engine 12 and comparing that flow rate to a maximum flow rate of fuel at the same speed and full throttle. In some embodiments, the processor determines the estimated load based on directly measuring the load using a torque sensor, an encoder, or a combination thereof.

[0048] In block 206 of process 200, the processor compares the estimated load of the gas turbine engine to a first threshold load. In certain embodiments, the first threshold load is less than a full load (e.g., a maximum load) of the gas turbine engine 12. For example, the threshold load may be less than 50, 60, 70, 80, or 90% of a full load of the gas turbine engine 12.

[0049] In block 208 of process 200, the processor, based on the comparison, commands an actuator (e.g., a valve) to divert a portion of the exhaust stream output by the exhaust gas recirculation (EGR) system 60 of the gas turbine engine 12 to the multi-stage compressor 93. In certain embodiments, the processor commands the multi-stage compressor 93 to compress the exhaust stream and / or to inject the exhaust stream into the compressor discharge casing 55 of the gas turbine engine 12. In certain embodiments, the processor commands the multi-stage compressor 93 to compress the exhaust stream and / or to inject the exhaust stream into one or more exhaust injection locations 59 downstream of compression by the compressor 52.

[0050] A technical effect of an embodiment of the present disclosure includes extracting a portion of exhaust gas from an EGR system 60 of a gas turbine system 12 and injecting the portion of the exhaust gas into one or more exhaust injection locations 59 (e.g., the compressor discharge casing 55, the combustor 54, and / or the turbine 56 of the gas turbine system) to improve the efficiency and power output of the gas turbine system 12. By injecting a portion of the exhaust gas from the EGR system 60 into the one or more exhaust injection locations 59, the power output and efficiency of the gas turbine system 12 are increased sufficiently to offset power and efficiency losses due to the operation of the gas processing system 18, particularly the carbon capture system 100. It may be appreciated that using a multi-stage centrifugal compressor 93 to compress the exhaust gas prior to injection into the one or more exhaust injection locations 59 may be 40% more efficient at producing compressed exhaust gas than the axial compressor 52 of the gas turbine system 12. Additionally, it may be recognized that injecting exhaust gases output by the EGR system 60 into one or more exhaust injection locations 59 (e.g., the compressor discharge casing 55, the combustor 54, and / or the turbine 56) can increase the power output (e.g., capacity) of the gas turbine system by up to 10%, regardless of ambient conditions. Again, a significant advantage of the disclosed embodiments includes the system 10 recovering a portion of the efficiency and power lost due to the carbon capture system 100, without substantially reducing the efficiency and power output of the system 10, such that the carbon footprint is relatively low, zero, or negative.

[0051] The subject matter described in detail above may be defined by one or more of the clauses set forth below.

[0052] The system includes a gas turbine engine including a compressor, a combustor, and a turbine; and an exhaust gas recirculation (EGR) system configured to recirculate a first portion of an exhaust flow from the gas turbine engine to an intake of the gas turbine engine; and an exhaust gas injection system including a multi-stage compressor including a plurality of stages, the multi-stage compressor configured to compress a second portion of the exhaust flow, and an intercooler coupled to the multi-stage compressor, wherein the exhaust gas injection system is configured to inject the second portion of the exhaust flow into the gas turbine engine at one or more exhaust injection locations to provide power augmentation for the gas turbine engine, the one or more exhaust injection locations being axially spaced from the intake of the gas turbine engine.

[0053] The system of the preceding clause, including a controller having a memory, a processor, and instructions stored in the memory and executable by the processor to control the exhaust gas injection system to adjust the power augmentation based on the load of the gas turbine engine, the power demand by the carbon capture system, or a combination thereof.

[0054] The system of any preceding clause, including a carbon capture system configured to capture carbon from an exhaust stream from the gas turbine engine, wherein the power augmentation is configured to compensate for power and / or efficiency losses caused by operation of the carbon capture system.

[0055] The system of any preceding clause, wherein the carbon capture system comprises a sorbent-based carbon capture system, a solvent-based carbon capture system, a cryogenic carbon capture system, or a combination thereof, and wherein the carbon capture system is configured to capture at least carbon dioxide (CO2) from the exhaust stream.

[0056] The system of any preceding clause, including a controller having a memory, a processor, and instructions stored in the memory and executable by the processor to control the exhaust gas injection system to adjust the power boost based on operation of the carbon capture system.

[0057] The system of any preceding clause, wherein the controller is configured to control the exhaust gas injection system to regulate the second portion of the exhaust flow to one or more exhaust injection locations, the one or more exhaust injection locations including a final stage of the compressor, a compressor discharge casing of the compressor, a combustor, a turbine, or a combination thereof.

[0058] The system of any preceding clause, wherein one or more exhaust injection locations include a final stage of the compressor.

[0059] The system of any preceding clause, wherein the one or more exhaust injection locations include a compressor discharge casing of the compressor.

[0060] The system of any preceding clause, wherein the one or more exhaust injection locations include a turbine.

[0061] 10. The system of any preceding clause, wherein the one or more exhaust injection locations include a plurality of turbine injection locations into a turbine of a gas turbine engine, and wherein a plurality of stages of a multi-stage compressor are coupled to a plurality of turbine injection locations.

[0062] The system of any preceding clause, wherein the exhaust gas injection system includes an engine configured to drive the multi-stage compressor, the engine producing engine exhaust gases, and the heat exchanger configured to transfer heat from the engine exhaust gases to a second portion of the exhaust stream compressed by the multi-stage compressor.

[0063] The system of any preceding clause, wherein the engine includes a reciprocating piston-cylinder engine having a turbocharger powered by at least a portion of the engine exhaust gases.

[0064] The system of any preceding clause, wherein the gas turbine system includes a heat recovery steam generator (HRSG) configured to receive at least a portion of the engine exhaust gas from the engine and at least a portion of the exhaust stream from the gas turbine engine.

[0065] The system of any preceding clause, wherein the exhaust gas injection system includes a plurality of valves, the plurality of valves including a first valve disposed between the heat exchanger and the engine, a second valve disposed between the heat exchanger and an intercooler, a third valve disposed between the heat exchanger and a compressor discharge casing of a compressor of the gas turbine engine, a fourth valve disposed between the EGR system and the multi-stage compressor, or a combination thereof.

[0066] 10. The system of any preceding clause, including a controller having a memory; a processor; and instructions stored in the memory and executable by the processor to receive a signal indicative of a load of the gas turbine engine, determine an estimated load of the gas turbine engine based on the signal, compare the estimated load of the gas turbine engine to a threshold load, and, in response to the estimated load exceeding the threshold load, control the fourth valve to bypass a second portion of the exhaust flow to the multi-stage compressor.

[0067] The system includes a controller having a memory, a processor, and instructions stored in the memory and executable by the processor to control a first portion of an exhaust flow from a gas turbine engine through an exhaust gas recirculation (EGR) system to an intake of the gas turbine engine, the gas turbine engine including a compressor, a combustor, and a turbine. The controller is further configured to control a second portion of the exhaust flow from the gas turbine engine through an exhaust gas injection system to one or more exhaust injection locations axially spaced from the intake of the gas turbine engine to provide power augmentation for the gas turbine engine.

[0068] The system of the preceding clause, wherein the controller is configured to adjust the power augmentation based on a load on the gas turbine engine, a power demand by the carbon capture system, or a combination thereof.

[0069] The system of any preceding clause, wherein the exhaust gas injection system includes a multi-stage compressor having a plurality of stages; and an intercooler coupled to the multi-stage compressor.

[0070] 1. A method comprising: controlling a first portion of an exhaust flow from a gas turbine engine through an exhaust gas recirculation (EGR) system to an intake of the gas turbine engine, the gas turbine engine including a compressor, a combustor, and a turbine. The method further comprises controlling a second portion of the exhaust flow from the gas turbine engine through an exhaust gas injection system to one or more exhaust injection locations, the one or more exhaust injection locations being axially spaced from the intake of the gas turbine engine, to provide power augmentation for the gas turbine engine.

[0071] The method of the preceding clause, wherein controlling the second portion of the exhaust stream includes adjusting the power boost based on a load of the gas turbine engine, a power demand by the carbon capture system, or a combination thereof.

[0072] Examples are used herein to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using the devices or systems and practicing the incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims. [Explanation of symbols]

[0073] 10 Systems 12 Gas turbine systems, gas turbine engines 14 Steam Turbine System 16. Heat recovery steam generator (HRSG) 18 Gas Treatment System 20 Gas capture system, carbon capture system 22 Controller 40 Axial or Axial 42 Radial or axial 44 Circumferential or axial 50 Air intake 52 Compressor 54 Combustion Machine 55 Compressor discharge casing 56 Turbine 58 Load 59 Exhaust injection position 60 Exhaust Gas Recirculation (EGR) System 61 Exhaust gas 63 Cooling and cleaning module 68 steps 70 High Pressure (HP) Steam Section 72 Intermediate Steam (IP) Section 74 Low Pressure (LP) Steam Section 76 HP Steam 78 IP Steam 80 LP steam 82 HP steam turbine 84 IP steam turbine 86 LP steam turbine 88 Condensate Line 90 Condenser 92 Pump 93 Multi-stage compressor 94 Load 95 Air intake part 97 Exhaust Gas Injection System 98 steps 99 Injection part 100 Carbon Capture System 101 Intercooler 102 Components 103 Engine 104 Components 105 valves 106 Components 107 Gas trapping part 109 Heat exchanger 110 Processed gas 112 Trapped Gas 114 Compression System 116 Storage and / or Pipeline Systems 118 Exhaust gas circuit 120 processors 122 memory 124 Command 126 Communication Circuit 128 valves 130 Exhaust gas circuit 131 Valve 132 Exhaust gas circuit 133 Fourth Valve 134 Exhaust gas circuit 135 Valve 136 Valve 140 Rest 142 steps 144 steps 146 steps 148 Air 150 fuel 152 Engine exhaust gas 153 Coolant 154 Heat exchanger 156 Compressed Exhaust Gas 158 Turbocharger 160 Final stage part 161 Turbine part 162 Turbine position 164 outer casing 165 first axial position 166 Second Axial Position 168 Upstream part 170 downstream part 172 First Valve 174 Second Valve 175 Exhaust gas circuit 176 Third Valve 178 Third Valve 179 Valve 180 sensors 181 Valve 182 Sensors

Claims

1. A system (10), comprising: a gas turbine engine including a compressor (52), a combustor (54), and a turbine (56); an exhaust gas recirculation (EGR) system (60) configured to recirculate a first portion of the exhaust flow from the gas turbine engine (12) to an intake (50) of the gas turbine engine (12); a gas turbine system (12) comprising: a multi-stage compressor (93) comprising a plurality of stages (98), the multi-stage compressor (93) configured to compress a second portion of the exhaust stream; an intercooler (101) coupled to the multi-stage compressor (93); an exhaust gas injection system (97) comprising: the exhaust gas injection system (97) is configured to inject the second portion of the exhaust flow into the gas turbine engine (12) at one or more exhaust injection locations (59) to provide power augmentation for the gas turbine engine (12), the one or more exhaust injection locations (59) being axially spaced from the intake (50) of the gas turbine engine (12).

2. 10. The system of claim 1, comprising a controller having a memory, a processor, and instructions stored in the memory and executable by the processor to control the exhaust gas injection system to adjust the power boost based on a load on the gas turbine engine, a power demand by a carbon capture system, or a combination thereof.

3. 2. The system (10) of claim 1, comprising a carbon capture system (20, 100) configured to capture carbon from the exhaust stream from the gas turbine engine (12), and wherein the power augmentation is configured to compensate for power and / or efficiency losses caused by operation of the carbon capture system (20, 100).

4. The carbon capture system (20, 100) comprises a sorbent-based carbon capture system, a solvent-based carbon capture system, a cryogenic carbon capture system, or a combination thereof, and the carbon capture system (20, 100) captures at least carbon dioxide (CO ) from the exhaust stream. ２ 4. The system (10) of claim 3, configured to capture:

5. 4. The system (10) of claim 3, comprising a controller (22) having a memory (122), a processor (120), and instructions (124) stored in the memory (122) and executable by the processor (120) to control the exhaust gas injection system (97) to adjust the power boost based on the operation of the carbon capture system (20, 100).

6. 6. The system of claim 5, wherein the controller is configured to control the exhaust gas injection system to regulate the second portion of the exhaust flow to the one or more exhaust injection locations, the one or more exhaust injection locations comprising a final stage of the compressor, a compressor discharge casing of the compressor, the combustor, the turbine, or a combination thereof.

7. 2. The system of claim 1, wherein the one or more exhaust injection locations include a plurality of turbine injection locations for the turbine of the gas turbine engine, and wherein the plurality of stages of the multi-stage compressor are coupled to the plurality of turbine injection locations.

8. 2. The system of claim 1, wherein the exhaust gas injection system comprises an engine configured to drive the multi-stage compressor, the engine producing engine exhaust gases, and a heat exchanger configured to transfer heat from the engine exhaust gases to the second portion of the exhaust stream compressed by the multi-stage compressor.

9. 9. The system (10) of claim 8, wherein the engine (103) comprises a reciprocating piston-cylinder engine having a turbocharger (158) driven by at least a portion of the engine exhaust gases (152).

10. 10. The system (10) of claim 8, wherein the gas turbine system (12) comprises a heat recovery steam generator (HRSG, 16) configured to receive at least a portion of the engine exhaust gas (152) from the engine (103) and at least a portion of the exhaust stream from the gas turbine engine (12).

11. The exhaust gas injection system (97) comprises a plurality of valves (128), the plurality of valves (128) comprising: a first valve (172) disposed between the heat exchanger (109) and the engine (103); a second valve (174) disposed between the heat exchanger (109) and the intercooler (101); a third valve (176, 178) disposed between the heat exchanger (109) and a compressor discharge casing (55) of the compressor (52) of the gas turbine engine (12); a fourth valve (133) disposed between the EGR system (60) and the multi-stage compressor (93); or 9. The system (10) of claim 8, comprising:

12. A memory (122), a processor (120), and a method stored in the memory (122), receiving a signal indicative of a load on the gas turbine engine; determining an estimated load on the gas turbine engine (12) based on the signal; comparing the estimated load of the gas turbine engine (12) to a threshold load; and instructions executable by the processor to control the fourth valve to divert the second portion of the exhaust flow to the multi-stage compressor in response to the estimated load exceeding the threshold load.

13. 13. A method of augmenting power output from a gas turbine engine (12) using a system according to any one of claims 1 to 12, said method comprising: controlling a first portion of an exhaust flow from a gas turbine engine (12) through an exhaust gas recirculation (EGR) system (60) to an intake (50) of the gas turbine engine (12), the gas turbine engine (12) comprising a compressor (52), a combustor (54), and a turbine (56); controlling a second portion of the exhaust flow from the gas turbine engine (12) through an exhaust gas injection system (97) to one or more exhaust injection locations (59) to provide power augmentation for the gas turbine engine (12), the one or more exhaust injection locations (59) being axially spaced from the intake (50) of the gas turbine engine (12); A method comprising:

14. 14. The method of claim 13, wherein controlling the second portion of the exhaust flow comprises adjusting the power boost based on a load on the gas turbine engine, a power demand by a carbon capture system, or a combination thereof.

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