System and method having an oxidant supply unit for a duct burner of a heat recovery steam generator

Abstract

The system includes a duct burner configured to add combustion heat to exhaust gases led through a heat recovery steam generator (HRSG), a fuel supply unit configured to supply fuel to the duct burner, and an oxidizer supply unit configured to supply an oxidizer to the duct burner. The system also includes a control device having a memory, a processor, and instructions stored in the memory, which are executable by the processor, to control the fuel supply unit to supply fuel to the duct burner, and to control the oxidizer supply unit to supply an oxidizer to the duct burner, the control of the oxidizer supply unit being based on a comparison of the oxygen content in the exhaust gas with an oxygen threshold.

Description

[Technical Field]

[0001] This application relates to a system and method for supplying an oxidizer to a duct burner of a heat recovery steam generator (HRSG) located downstream of a combustion system (e.g., a gas turbine system), generally during exhaust gas recirculation (EGR) mode. [Background technology]

[0002] Industrial plants, such as combustion-driven power plants, may include HRSGs for generating steam using heat from exhaust gases produced by the combustion system. The combustion system may include gas turbine engines, reciprocating piston cylinder engines, furnaces, or other industrial equipment. The exhaust gases may include one or more undesirable gases, such as acidic gases and / or greenhouse gases. For example, undesirable gases include carbon oxides such as carbon dioxide (CO2) and carbon monoxide (CO2) X ), nitrogen oxides such as nitrogen dioxide (NO2) (NO X ), as well as sulfur oxides such as sulfur dioxide (SO2) (SO2) X ) may contain. CO2 is both an acidic gas and a greenhouse gas. Therefore, the use of gas treatment systems and / or exhaust gas recirculation (EGR) systems can help reduce the emission of undesirable gases. For example, an EGR system reduces the oxygen content in the exhaust gas by replacing a portion of the intake air with recirculated exhaust gas. x This reduces the problem. Unfortunately, low oxygen content can complicate the steam generation process in the HRSG. As a result, heat must be applied to the HRSG while addressing the low oxygen content in the exhaust gas (e.g., insufficient oxygen for the duct burner). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] European Patent Application Publication No. 3287612 [Overview of the project]

[0004] The following is a summary of specific embodiments corresponding to the scope of the subject matter originally claimed. These embodiments are not intended to limit the scope of the claimed embodiments, but rather to provide a brief overview of possible forms of the subject matter. In fact, the embodiments claimed herein may include a variety of forms that may be similar to or different from the embodiments described below.

[0005] The system includes a duct burner configured to add combustion heat to exhaust gases led through a heat recovery steam generator (HRSG), a fuel supply unit configured to supply fuel to the duct burner, and an oxidizer supply unit configured to supply an oxidizer to the duct burner. The system also includes a control device having a memory, a processor, and instructions stored in the memory, which are executable by the processor, to control the fuel supply unit to supply fuel to the duct burner, and to control the oxidizer supply unit to supply an oxidizer to the duct burner, the control of the oxidizer supply unit being based on a comparison of the oxygen content in the exhaust gas with an oxygen threshold.

[0006] The system includes a control device having memory, a processor, and instructions stored in memory, which are executable by the processor and control a fuel supply unit to supply fuel to a duct burner of a heat recovery steam generator (HRSG), the duct burner being configured to add combustion heat to the exhaust gases led through the HRSG. The control device is also configured to control an oxidizer supply unit to supply an oxidizer to the duct burner, the control of which is based on a comparison of the oxygen content in the exhaust gases with an oxygen threshold.

[0007] The method includes controlling a fuel supply unit via a control device to supply fuel to a duct burner of a heat recovery steam generator (HRSG), wherein the duct burner is configured to add combustion heat to the exhaust gases guided through the HRSG. The method further includes controlling an oxidizer supply unit via a control device to supply an oxidizer to the duct burner, wherein the control of the oxidizer supply unit is based on a comparison of the oxygen content in the exhaust gases with an oxygen threshold.

[0008] These, as well as other features, aspects, and advantages of the technology disclosed herein will be better understood by reading the following detailed description with reference to the accompanying drawings, in which, throughout the drawings, similar reference numerals represent similar parts. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram of one embodiment of a combined cycle system comprising a gas turbine system, a steam turbine system, a heat recovery steam generator (HRSG), a gas processing system having one or more gas capture systems, and a thermal control system having a duct burner coupled to the HRSG. [Figure 2] Figure 1 is a schematic diagram of one embodiment of a combined cycle system, showing one embodiment of a thermal control system having multiple oxidizer supply units and fuel supply units coupled to a duct burner. [Figure 3] Figures 1 and 2 are flowcharts of one embodiment of the process for operating the combined cycle system, and show the control logic for operating the thermal control system. [Figure 4] Figures 1 and 2 are flowcharts of one embodiment of the process for operating the combined cycle system, and show the control logic for operating the thermal control system. [Modes for carrying out the invention]

[0010] The following describes one or more specific embodiments of the systems and methods disclosed herein. For the sake of brevity, not all features of the actual embodiments may be described herein. It should be understood that, as with any engineering or design project, in developing such actual embodiments, numerous embodiment-specific decisions must be made to achieve the developer's specific objectives, such as compliance with system-related and business-related constraints, and these constraints may differ from embodiment to embodiment. Furthermore, while such development work can be complex and time-consuming, it should be understood that for those skilled in the art who benefit from this disclosure, it is still a routine design, fabrication, and manufacturing effort.

[0011] When introducing elements of various embodiments relating to the embodiments disclosed herein, “a,” “an,” “the,” and “said” mean that there are one or more elements. The terms “equip,” “include,” and “have” are comprehensive and mean that there may be additional elements other than those listed.

[0012] The disclosed embodiments include a system and method for applying heat to a heat recovery steam generator (HRSG) using a duct burner, wherein the exhaust gas flowing into the HRSG has a low oxygen content. In particular, the disclosed embodiments allow an oxidizer supply unit to directly or indirectly supply an oxidizer (e.g., air, oxygen, oxygen-enriched air, oxygen-reduced air, or other oxygen-containing gas) to the duct burner based on a comparison of the oxygen content in the exhaust gas with an oxygen threshold (e.g., a lower oxygen threshold, or both a lower and upper oxygen threshold). For example, the disclosed embodiments may monitor the temperature and oxygen content of the exhaust gas, compare the temperature to a temperature threshold, compare the oxygen content to an oxygen threshold, and control both the fuel supply unit and the oxygen supply unit based on the comparison. If the temperature exceeds a temperature threshold (e.g., a lower temperature threshold), the duct burner does not need to operate to apply heat to the exhaust gas. If the temperature falls below a temperature threshold (e.g., a lower temperature threshold), heat may be added to the exhaust gas by operating the duct burner and controlling the fuel supply unit to supply fuel, and (if necessary) facilitating combustion by controlling the oxidizer supply unit to supply oxidizer. While the duct burner is operating, if the oxygen content in the exhaust gas falls below an oxygen threshold (e.g., a lower oxygen threshold) due to exhaust gas recirculation (EGR) in a combustion system upstream of the HRSG (e.g., a gas turbine system), the oxidizer supply unit may operate to supply enough oxidizer (e.g., oxidizer increase or oxidizer enrichment) to raise the oxygen content to at least meet or exceed the oxygen threshold. In certain embodiments, the lower oxygen threshold may be about 10, 11, or 12 (plus or minus 0.5) volume percent of oxygen in the exhaust gas. In some embodiments, the lower oxygen threshold may be about 10.5 (plus or minus 0.1, 0.2, 0.3, 0.4, or 0.5) volume percent of oxygen in the exhaust gas. Instead, if the oxygen content in the exhaust gas is above the oxygen threshold, the oxidizer supply unit may reduce or stop the supply of oxidizer to maintain the oxygen content at least above the oxygen threshold.

[0013] In certain embodiments, the oxidizer supply unit may include an ejector (e.g., a variable ejector) and / or a compressor. For example, the oxidizer supply unit may include a compressor driven by a steam turbine, a compressor driven by an electric drive unit (e.g., an electric motor), a compressor driven by a reciprocating engine, a compressor driven by a gas turbine, and / or another suitable oxidizer supply unit. The ejector may be configured to take the oxidizer into a power fluid (e.g., EGR gas) to provide an oxidizer-fluid mixture, which is then supplied to the duct burner. The compressor may include an axial flow compressor, a centrifugal compressor, a rotary screw compressor, a rotary vane compressor, a reciprocating piston compressor, or any combination thereof. Thus, the oxidizer supply unit allows the duct burner to operate to apply the necessary heat to the HRSG, particularly in systems having an EGR and a gas treatment system (e.g., a gas capture system), as will be described in more detail below.

[0014] Accordingly, in combination with the duct burner enhanced by the oxidizer supply unit, the disclosed embodiments are configured to reduce carbon dioxide emissions from combustion systems, such as combustion-driven power plants and / or combined-cycle power plants, using a gas treatment system having one or more gas capture systems. The gas capture systems are configured to remove undesirable gases (e.g., CO2) from the intake air and / or exhaust gases of the combustion system. The gas capture systems may include adsorbent-based gas capture systems, solvent-based gas capture systems, cryogenic gas capture systems, or combinations thereof. For example, a gas capture system (e.g., an adsorbent-based gas capture system) may include one or more temperature swing adsorption (TSA) units or adsorbents that adsorb undesirable gases at a first temperature (e.g., low temperature) and desorb undesirable gases at a second temperature (e.g., high temperature) depending on the temperature swing. For example, an adsorbent-based gas capture system is configured to adsorb undesirable gases onto an adsorbent material and then desorb the undesirable gases from the adsorbent material using a heat source (e.g., steam from an HRSG, steam from a steam turbine system, or another steam source). Adsorption processes are exothermic, while desorption processes are endothermic. As a further example, a solvent-based gas capture system may include an absorber configured to absorb unwanted gases into a solvent, and a stripper configured to remove the unwanted gases from the solvent using vapor (e.g., vapor from an HRSG, vapor from a vapor turbine system, or other vapor source). While solvent-based gas capture systems are described as using a solvent as the absorption fluid, disclosed embodiments may use any suitable absorption fluid to capture unwanted gases. Thus, solvent-based gas capture systems may also be described as fluid-absorbing gas capture systems.

[0015] As described below, duct burners enhanced with an oxidizer supply can be used in various configurations with HRSG. Specific examples are provided below, but duct burners enhanced with an oxidizer supply can be used in any suitable way with or without an exhaust gas recirculation (EGR) system, with or without various gas capture systems, and with various combustion systems.

[0016] Figure 1 is a block diagram of one embodiment of a combined cycle system 10 having a gas turbine system 12, a steam turbine system 14, a heat recovery steam generator (HRSG) 16, and a gas processing system 18 having one or more gas capture systems 20. As will be described in more detail below, the combined cycle system 10 includes a thermal control system 22 coupled to the HRSG 16, the thermal control system 22 being configured to regulate the temperature of the exhaust gas flow through the HRSG 16. In the illustrated embodiment, the thermal control system 22 includes one or more duct burners 24 coupled to a fluid supply system 25, the duct burners 24 being located inside the HRSG 16 along the exhaust flow path. The fluid supply system 25 includes an oxidizer supply unit or oxidizer supply system 26 and a fuel supply unit or fuel supply system 28, coupled to the duct burners 24. The oxidizer supply unit 26 may also be described as an oxidizer augmentation or enrichment system, such as an oxygen and / or air augmentation system. The oxidizer supply unit 26 may be part of the original thermal control system 22, or it may be added to the existing duct burner 24 as part of a modification kit. In some embodiments, the entire thermal control system 22 may be a modification kit for an existing HRSG 16 and combined cycle system 10.

[0017] When the temperature of the exhaust gas flow drops below a temperature threshold (e.g., a lower temperature threshold), the thermal control system 22 may selectively operate the duct burner 24 to burn the fuel from the fuel supply unit 28 with oxygen in the exhaust gas flow and / or an oxidant from the oxidant supply unit 26. When the temperature of the exhaust gas flow is above the temperature threshold, the duct burner 24 may not be operated (or the heat output of the duct burner 24 may be reduced). Additionally or alternatively, when the gas turbine system 12 is operating in an exhaust gas recirculation (EGR) mode, the thermal control system 22 may selectively operate the duct burner 24 to burn the fuel from the fuel supply unit 28 with oxygen in the exhaust gas flow and / or an oxidant from the oxidant supply unit 26. When the gas turbine system 12 is not operating in the EGR mode, the duct burner 24 may not be operated (or the heat output of the duct burner 24 may be reduced). Various aspects of the thermal control system 22 will be described in more detail below.

[0018] In certain embodiments, the gas treatment system 18 includes one or more gas capture systems 20 for capturing undesirable gases (e.g., CO2) from gases such as exhaust gas and / or air. The gas capture system 20 may include an adsorbent-based gas capture system, a solvent-based gas capture system, a cryogenic gas capture system, or any combination thereof. Before describing the details of the gas treatment system 18, various aspects of the combined cycle system 10 will be described in more detail. For purposes of orientation in the drawings, reference may be made to an axial or axis 30, a radial or axis 32 extending radially away from the axial or axis 30, and a circumferential or axis 34 extending circumferentially around the axial or axis 30. The directions or axes 30, 32, and 34 may be based, for example, on the rotational axis 36 of the gas turbine system 12.

[0019] The gas turbine system 12 may include an intake section 40, a compressor or compressor section 42, a combustor section 44, a gas turbine or turbine section 46, and an exhaust section 48. The compressor section 42 may include at least one shaft 50 disposed along a rotating shaft 36, a casing 52 (e.g., an annular casing) disposed circumferentially around the at least one shaft 50, a plurality of rotary compressor blades 54 extending radially outward from the at least one shaft 50, and a plurality of stationary compressor vanes 56 extending radially inward from the casing 52 toward the at least one shaft 50. In the illustrated embodiment, the compressor section 42 may include a plurality of compressor stages 58, each having a plurality of compressor vanes 56 arranged circumferentially spaced around at least one shaft 50 in an axial position, and a plurality of compressor blades 54 arranged circumferentially spaced around at least one shaft 50 in different axial positions (i.e., the compressor vanes 56 and compressor blades 54 are spaced apart in the axial direction). Thus, the compressor section 42 is configured to receive a flow of intake gas 60 from the intake section 40 and gradually compress the intake gas 60 through the plurality of compressor stages 58. As will be described in more detail below, the intake gas 60 may include intake air, exhaust gas recirculation (EGR) flow or recirculated exhaust gas, or a combination thereof.

[0020] The combustor section 44 may include one or more combustors 62, such as a single annular combustor circumferentially disposed around the axis of rotation 36 or a plurality of combustors 62 circumferentially spaced around the axis of rotation 36. In the illustrated embodiment, each combustor 62 includes a head end portion 64 coupled to a combustion portion 66. The combustion portion 66 includes a combustion chamber 68, a combustor liner 70 circumferentially disposed around the combustion chamber 68, a flow sleeve 72 circumferentially disposed around the combustor liner 70, and a passage 74 extending between the combustor liner 70 and the flow sleeve 72. The passage 74 is configured to direct a compressed gas flow in the upstream direction 76 toward a head end chamber 78 disposed in the head end portion 64. The head end chamber 78 and the combustion chamber 68 of the combustor 62 are separated or divided from each other by an intermediate plate 80. In the head end chamber 78, a plurality of fuel nozzles 82 are coupled to the intermediate plate 80 and an end plate 84 of the head end portion 64. During operation, each combustor 62 receives compressed gas 86 (e.g., air, EGR, etc.) from the compressor section 42, sends the compressed gas 86 along the passage 74 toward the head end chamber 78 as indicated by arrow 76, and sends the compressed gas from the fuel nozzles 82 into the combustion chamber 68.

[0021] In certain embodiments, each combustor 62 may receive one or more fuel flows from a fuel system 88 coupled to a fuel nozzle 82, the fuel system 88 including a fuel supply system 90 coupled to one or more fuel circuits 92. For example, the fuel circuits 92 may include fuel circuits 94, 96, and 98 coupled to different sets of fuel nozzles 82. The fuel circuits 92 (e.g., 94, 96, and 98) may include fuel conduits, fuel manifolds, fuel valves, pressure regulators, and other flow control units. The fuel system 88 is configured to supply one or more fuels, such as liquid and / or gaseous fuels, to each of the fuel nozzles 82 for injection into the combustion chamber 68. The fuels may include natural gas, synthesis gas produced from a gasifier, methane, hydrogen, biofuels, fuel oil, or any combination thereof. In certain embodiments, the combined cycle system 10 may be a natural gas combined cycle system. The fuel supply system 90 may include a plurality of components for controlling the flow of various fluids to the combustor 62. For example, the fuel supply system 90 may include one or more components 100. In a particular embodiment, the components 100 may include one or more fuel tanks, fuel pumps, valves, pressure regulators, flow regulators, filters, water removal units, particulate removal units, manifolds, flow control devices, or any combination thereof.

[0022] The fuel nozzle 82 is configured to inject one or more fuels from the fuel system 88 and compressed gas 86 from the compressor section 42. In certain embodiments, the fuel nozzle 82 is configured to inject compressed air 104 from a compressor system 106 having an air compressor 108 coupled to a drive unit 110 such as an electric motor, a combustion engine, a shaft coupled to the gas turbine system 12, or another suitable drive unit. Additionally or alternatively, in certain embodiments, the compressor system 106 is configured to supply the compressed air 104 to the combustor section 44 via a compressor discharge casing of the compressor section 42 for delivery to the combustor section 44. However, any suitable air supply configuration may be used for the gas turbine system 12. For example, in certain embodiments of the gas turbine system 12 having exhaust gas recirculation (EGR), the compressor section 42 supplies compressed gas 86 (e.g., compressed exhaust gas) to each combustor 62, while the compressor system 106 supplies compressed air 104 to each combustor 62.

[0023] In a further example, in a particular embodiment of a gas turbine system 12 without exhaust gas recirculation (EGR), the compressor section 42 supplies compressed gas 86 (e.g., compressed air) to each combustor 62 without requiring an additional air supply. Thus, the compressor system 106 may optionally supply compressed air 104 to each combustor 62. During operation, fuel is combusted with air in the combustion chamber 68 of each combustor 62, thereby producing high-temperature combustion gas 112 which can be delivered from the combustion chamber 68 to the turbine section 46.

[0024] The turbine section 46 includes at least one shaft 114 arranged along the rotation axis 36, a casing 116 (e.g., an annular casing) circumferentially arranged around the at least one shaft 114, a plurality of rotating turbine blades 118 extending radially outward from the at least one shaft 114, and a plurality of stationary turbine vanes 120 extending radially inward from the casing 116 toward the at least one shaft 114. The turbine section 46 may also include a plurality of turbine stages 122, each having a plurality of turbine vanes 120 circumferentially spaced around the at least one shaft 114 in an axial position, and a plurality of turbine blades 118 circumferentially spaced around the at least one shaft 114 in different axial positions (i.e., the turbine vanes 120 and turbine blades 118 are spaced apart in the axial direction). The at least one shaft 114 may also be coupled to at least one shaft 50 of the compressor section 42 via at least one intermediate shaft 124. Furthermore, at least one shaft 114 may be coupled to a load 126 via a shaft 128. In certain embodiments, the load 126 may include a generator, machinery, a vehicle propulsion system, or any other suitable load. In the illustrated embodiment, the load 126 may be a generator, so the combined cycle system 10 becomes a combined cycle power plant. During operation, combustion gases 112 flow from the combustor 62 to the turbine section 46, and the combustion gases 112 gradually expand, driving the rotation of turbine blades 118 coupled to at least one shaft 114 of each turbine stage 122. In this way, the combustion gases 112 drive the turbine section 46, which in turn drives the compressor section 42 and the load 126 via interconnected shafts 50, 124, 114, and 128.

[0025] In certain embodiments, the gas turbine system 12 may be configured such that the shafts 50, 114, 124, and 128 and the connected compressor blades 54 and turbine blades 118 share a common direction of rotation. The shafts 50, 114, 124, and 128 may be removably coupled with shaft connectors such as flange joints. In some embodiments, some of the shafts may be combined to reduce the number of shafts. For example, all of the illustrated shafts 50, 114, and 124 may represent a common shaft that rotates in a common direction of rotation, such as clockwise or counterclockwise.

[0026] The gas turbine system 12 may be configured with or without a compressor system 106 and an exhaust gas recirculation (EGR) system 150. The EGR system 150 is configured to recirculate the exhaust gases 152, 184 output from the turbine section 46, after passing them through the HRSG 16, back to the compressor section 42 (e.g., via the intake section 40) for compression and delivery to the combustor section 44. However, the gas turbine system 12 may omit the EGR system 150 and only draw an airflow into the intake section 40 for compression by the compressor section 42.

[0027] In a particular embodiment of the gas turbine system 12 having an EGR system 150, recirculated exhaust gases 152, 184 flow through the intake section 40 and the compressor stages 58 of the compressor section 42, thereby compressing the recirculated exhaust gases as compressed gas 86 and delivering them to the combustor section 44. Furthermore, the combustor section 44 may receive compressed air 104 from the air compressor 108 of the compressor system 106 via fuel nozzles 82. The combustor section 44 also receives fuel from the fuel system 88 via fuel nozzles 82, etc. The fuel from the fuel system 88 then burns with air from the compressor system 106 to produce combustion gases 112, which then flow through the turbine section 46 and drive the rotation of the turbine blades 118 of each turbine stage 122. The recirculated exhaust gases reduce the oxygen content of the combustor section 44 by replacing the intake air, thereby reducing certain emissions associated with combustion in the combustor section 44 (e.g., nitrogen oxides (NOx)). X This helps reduce the generation of )). In this way, the recirculated exhaust gas reduces the oxygen content in the exhaust gas 152 delivered to HRSG16.

[0028] In a particular embodiment of the gas turbine system 12 without an EGR system 150, the compressor section 42 receives an airflow from the intake section 40, gradually compresses the airflow through the compressor stage 58, and delivers the compressed airflow as compressed gas 86 to the combustor section 44. The compressed airflow then facilitates the combustion of fuel from the fuel system 88, thereby producing hot combustion gas 112, which is delivered to the turbine section 46. In such an embodiment, the compressor system 106 may be excluded or included to supply additional compressed air 104 to the combustor section 44. Regardless of the configuration, the combustion gas 112 drives the rotation of the turbine blades 118 of the turbine stage 122, thereby rotating at least one shaft 114 coupled to at least one shaft 50 of the compressor section 42 and a shaft 128 that drives the load 126.

[0029] The exhaust gas 152 output by the turbine section 46 then passes through the HRSG 16, where heat can be transferred from the exhaust gas to water to generate steam for the steam turbine system 14. For example, the HRSG 16 may include a high-pressure section 160, an intermediate-pressure section 162, and a low-pressure section 164 in series, thereby generating high-pressure steam 166, intermediate-pressure steam 168, and low-pressure steam 170. The HRSG 16 may include multiple components in each section 160, 162, and 164, such as economizers, evaporators, superheaters, or any combination thereof. The components of the HRSG 16 may be connected to each other via various conduits and headers. In certain embodiments, the components of the HRSG16 include a finish high-pressure superheater, a secondary reheater, a primary reheater, a primary high-pressure superheater, an interstage overheat prevention device, an interstage overheat prevention device, a high-pressure evaporator, a high-pressure economizer, an intermediate-pressure evaporator, an intermediate-pressure economizer, a low-pressure evaporator, and a low-pressure economizer. The heat recovery steam generator 16 can supply high-pressure steam 166 to the high-pressure steam turbine 172, intermediate-pressure steam 168 to the intermediate-pressure steam turbine 174, and low-pressure steam 170 to the low-pressure steam turbine 176 of the steam turbine system 14. The steam drives the rotation of the blades in each steam turbine 172, 174, and 176, thereby driving a shaft 178 coupled to a load 180 such as a generator. The low-pressure steam turbine 176 can also return condensate 182 to the low-pressure section 164 of the HRSG16. Next, the HRSG16 can output the exhaust gas 152 as partially cooled exhaust gas 184, which can then pass through the gas treatment system 18.

[0030] As described above, the gas processing system 18 includes one or more gas capture systems 20. For example, the gas capture system 20 may include one or any combination of the gas capture systems 190, 192, and 194, each having multiple components (e.g., components 196, 198, 200, and 202). The gas capture systems 20 (e.g., 190, 192, and 194) are configured to acquire a capture gas 204 from the intake gas 60 and / or exhaust gases 152, 184. In the illustrated embodiment, the gas capture systems 20 (e.g., 190, 192, and 194) may capture and output carbon dioxide (CO2) as the capture gas 204, and the capture gas 204 may be further led to a compression system 206. For example, the compression system 206 may include one or more compressors configured to compress the capture gas 204 (e.g., CO2) and deliver the capture gas to a storage unit and / or pipeline 208.

[0031] Gas capture system 190 is located in, within, or upstream of the intake section 40 to capture undesirable gases from the intake air. Gas capture systems 192 and 194 are located downstream of the gas turbine system 12 and / or HRSG 16 to capture undesirable gases from the exhaust gases 152 and 184. Gas capture systems 20 (e.g., 190, 192, and 194) may include adsorbent-based gas capture systems, solvent-based gas capture systems, cryogenic gas capture systems, or any combination thereof, configured to remove and capture undesirable gases. In certain embodiments, gas capture systems 20 (e.g., 190, 192, and 194) may include carbon oxides (CO X The gas capture system 20 may be configured to remove and capture undesirable gases such as (e.g., carbon dioxide (CO2) and carbon monoxide (CO)), and therefore the gas capture system 20 may be described as a carbon capture system. In certain embodiments, the gas capture system 20 (e.g., 190, 192, and 194) may capture nitrogen oxides (NO2). X)(For example, undesirable gases such as nitrogen dioxide (NO2)) may be configured to be removed and captured, and for this reason, the gas capture system 20 is NO X The capture system may be described. In certain embodiments, the gas capture system 20 (e.g., 190, 192, and 194) is sulfur oxide (SO X )(For example, sulfur dioxide (SO2)) may be configured to be removed and captured, and for this reason, the gas capture system 20 is SO X The capture system may be described. In the following description, the gas capture system 20 (e.g., 190, 192, and 194) may be described as, by way of example, an adsorbent-based carbon capture system using an adsorbent material and / or, by way of example, a solvent-based carbon capture system using a liquid absorbent (e.g., a solvent). However, the embodiments disclosed herein may use any type or configuration of gas capture system 20 (e.g., 190, 192, and 194) as described above.

[0032] Each gas capture system 20 (e.g., 190, 192, and 194) may include components 196, 198, 200, and 202. Additionally, one or more components 210, 212, and 214 may be located upstream of the gas capture systems 192 and 194. In the case of adsorbent gas capture systems 20 (e.g., 190, 192, and 194), components 196, 198, 200, and 202 may include adsorbent material located on or within ducts (e.g., adsorption ducts, desorption ducts, and cooling ducts), contactors, cartridges, moving floors, rotating wheels, cartridges, or any combination thereof, along the flow paths of the intake gas 60 and / or exhaust gases 152, 184. The adsorbent gas capture system 20 is configured to adsorb undesirable gases (e.g., CO2) onto the adsorbent material in adsorption mode and to desorb undesirable gases from the adsorbent material in desorption mode. Components 196, 198, 200, and 202 may include cooling systems such as heat exchangers (e.g., fin and tube heat exchangers), heat pipes, and other thermal control systems coupled to the adsorbent material to help control the temperature of the adsorbent material during the adsorption mode (e.g., maintaining the adsorbent temperature between an upper and lower temperature threshold). Components 196, 198, 200, and 202 may also include heating systems such as heating fluid systems (e.g., steam systems, electric heaters, waste heat systems, etc.) configured to apply heat to the adsorbent material to desorb unwanted gases from the adsorbent material during the desorption mode. The adsorbent gas capture system 20 may also include other suitable components 196, 198, 200, and 202 supporting the adsorbent material.

[0033] In the case of the solvent-based gas capture system 20 (e.g., 190, 192, and 194), components 196, 198, 200, and 202 may include one or more absorbers, one or more strippers, and a solvent circuit passing through the absorbers and strippers. The absorbers are configured in absorption mode to absorb unwanted gases (e.g., CO2) into the solvent, thereby outputting a treated gas (e.g., treated air or treated exhaust gas) and a gas-rich solvent (e.g., CO2-rich solvent). The strippers are configured in desorption mode to remove unwanted gases from the gas-rich solvent, thereby outputting a gas-dilute solvent (e.g., CO2-dilute solvent) back into the absorber, and outputting the captured gas 204. Components 196, 198, 200, and 202 may include one or more cooling systems, such as heat exchangers (e.g., finned and tubular heat exchangers), heat pipes, and other thermal control systems coupled to the absorber to help control the solvent temperature (e.g., maintain the solvent temperature within upper and lower temperature thresholds) in order to improve the efficiency of the absorption mode. In certain embodiments, the cooling system may be arranged with multiple cooling circuits, each having a heat exchanger, heat pipe, or other cooler, and the gas capture system 20 may selectively use each cooling circuit depending on the solvent temperature and the need for cooling. Components 196, 198, 200, and 202 may also include a heating system, such as a heating fluid system (e.g., a steam system, an electric heater, a waste heat system, etc.) coupled to the stripper, the heating system being configured to add heat to the gas-rich solvent in order to desorb unwanted gases from the gas-rich solvent during the desorption mode. Components 196, 198, 200, and 202 may also include a reboiler coupled to the stripper, pumps and valves for controlling the flow of solvent through the solvent circuit between the absorber and the stripper, and a heat exchanger for cooling the gas-dilute solvent supplied to the absorber and heating the gas-rich solvent supplied to the stripper. The solvent system gas capture system 20 may also include other suitable components 196, 198, 200, and 202 supporting the absorber and stripper.

[0034] In certain embodiments, components 196, 198, 200, and 202 of the gas capture system 20, and / or components 210, 212, and 214 upstream from the gas capture systems 192 and 194, may include one or more of the following: a dryer or moisture removal system (e.g., a water-gas separator), a particulate removal system (e.g., a filter and / or a solid-gas separator), one or more booster fans configured to boost the flow of the gas being processed, one or more valves for controlling the flow of gas to the gas capture system 20, a bypass system configured to bypass the gas capture system 20, or any combination thereof. For example, components 210, 212, and 214 may include a water removal unit, a booster fan, and a valve, respectively. The separator may include a gravity separator, a centrifuge, or a combination thereof. In some embodiments, the gas capture system 20 (e.g., 190, 192, and 194) may be described as multiple gas capture stages. However, in some embodiments, the gas processing system 18 may include only a single stage and / or gas capture system 20. For example, the gas capture system 20 may include just one, two, or all three of the gas capture systems 190, 192, and / or 194.

[0035] In certain embodiments, the exhaust gas 184 may flow to the EGR system 150, partially or entirely bypassing the gas treatment system 18, and / or the exhaust gas 184 may flow partially or entirely through the gas treatment system 18 before flowing to the EGR system 150. The EGR system 150 may include various conduits, valves, and flow control units configured to supply at least a portion of the exhaust gas 152, 184 (e.g., the EGR flow) to the intake section 40 and recirculate it through the compressor section 42. In certain embodiments, the EGR system 150 includes one or more exhaust gas purification systems, treatment systems, and / or cooling systems.

[0036] In the illustrated embodiment, the combined cycle system 10 also includes a control device 220 coupled to a gas turbine system 12, a steam turbine system 14, an HRSG 16, a gas processing system 18, a thermal control system 22, a fuel system 88, an EGR system 150, a compression system 242, and various sensors 222 distributed throughout the combined cycle system 10. In the illustrated embodiment, the control device 220 includes one or more processors 224, a memory 226, instructions 228 stored in the memory 226 and executable by the processors 224, and a communication circuit 230 configured to communicate with the sensors 222 and various devices throughout the combined cycle system 10. For example, the control device 220 is configured to control the delivery and distribution of fuel from the fuel system 88 to the fuel nozzles 82 of the combustor section 44. In certain embodiments, the control device 220 is configured to control the operation of the gas capture system 20 (e.g., 190, 192, and 194) by controlling the operating mode (e.g., adsorption mode and desorption mode), controlling cooling and heating, controlling the flow of various fluids (e.g., cooling and heating fluids) through the gas capture system 20, or any combination thereof. In certain embodiments, the control device 220 is configured to control the operation of the thermal control system 22, for example, by controlling combustion by the duct burner 24 by controlling the oxidizer supply unit 26 and fuel supply unit 28 of the fluid supply system 25. For example, the control device 220 may monitor sensor feedback (e.g., temperature sensor, oxygen sensor) indicating the temperature and oxygen content of the exhaust gas 152 and control the oxidizer supply unit 26 and fuel supply unit 28 based on a comparison of the temperature with a temperature threshold (e.g., a lower temperature threshold, or both a lower and upper temperature threshold), and a comparison of the oxygen content with an oxygen threshold (e.g., a lower oxygen threshold, or both a lower and upper oxygen threshold).The control device 220 can also control the oxidizer supply unit 26 and the fuel supply unit 28 based on the operating modes of the combined cycle system 10, such as the EGR mode in which the EGR system 150 provides EGR flow to the gas turbine system 12, and the non-EGR mode in which the EGR system does not provide EGR flow to the gas turbine system 12. Additional control modes of the thermal control system 22 are described below.

[0037] Sensor 222 (indicated as "S") is configured to monitor various operating parameters of the combined cycle system 10. In certain embodiments, sensor 222 includes a temperature sensor, a pressure sensor, a flow rate sensor, a fluid composition sensor (e.g., a gas composition sensor), a vibration sensor, a clearance sensor, a speed sensor, a humidity and / or moisture sensor, or any combination thereof. Sensor 222 may monitor parameters (e.g., temperature, pressure, flow rate, and fluid composition) at one or more locations in the compressor section 42, the combustor section 44, the turbine section 46, the gas processing system 18, the steam turbine system 14, the HRSG 16, the thermal control system 22, or any combination thereof.

[0038] For example, sensor 222 may monitor compressor parameters (e.g., pressure ratio between the inlet and outlet of compressor section 42), combustion gas parameters (e.g., firing temperature and combustion dynamics), turbine parameters (e.g., temperature and pressure at each turbine stage, turbine inlet, and turbine exhaust), and exhaust gas emissions. As a further example, the exhaust gas emissions monitored by sensor 222 may include carbon oxides such as carbon dioxide (CO2) and carbon monoxide (CO2). X ), nitrogen oxides such as nitrogen dioxide (NO2) (NO X ), sulfur oxides such as sulfur dioxide (SO2) (SO XThis may include unburned hydrocarbons, particulate matter, and other undesirable exhaust emissions. As a further example, sensor 222 may monitor the temperature of the gas capture system 20, such as the temperature of the adsorbent material in an adsorbent gas capture system, the temperature of the solvent in a solvent gas capture system, or any combination thereof. In response to feedback from sensor 222, control device 220 may adjust the operating mode, fluid flow, heating, cooling, or any combination thereof in the gas capture system 20. As a further example, sensor 222 may monitor the temperature, pressure, flow rate, and oxygen content of exhaust gas 152 flowing into and / or through HRSG 16, thereby facilitating the control of a thermal control system 22 that adjusts the temperature of exhaust gas 152 via the operation of a duct burner 24.

[0039] The control device 220 is configured to control the thermal control system 22 to selectively heat the exhaust gas 152 supplied to the HRSG 16, maintaining the exhaust gas temperature between an upper and lower temperature threshold. The thermal control system 22 (e.g., controlled by the control device 220) is configured to selectively heat the exhaust gas via a duct burner 24 (or a plurality of duct burners 24). Thus, one or more sensors 222 (e.g., temperature sensors) are coupled to the HRSG 16 and / or the upstream duct piping of the HRSG 16, the upstream side of the duct burner 24, the duct burner 24, and / or the downstream side of the duct burner 24 to monitor the temperature of the exhaust gas 152. For example, at least one sensor 222 (e.g., temperature sensor) may be located downstream of the duct burner 24 to monitor the temperature of the exhaust gas 152, including any temperature adjustments achieved by the duct burner 24. If the temperature of the exhaust gas 152 falls below a temperature threshold, the thermal control system 22 (e.g., controlled by the control device 220) is configured to increase the temperature of the exhaust gas 152 by supplying fuel from the fuel supply unit 28 and (if necessary) oxidizer from the oxidizer supply unit 26 to the duct burner 24, thereby providing combustion in or upstream of the HRSG 16. If the temperature of the exhaust gas 152 is above the temperature threshold, the thermal control system 22 (e.g., controlled by the control device 220) is configured to stop or reduce the supply of fuel from the fuel supply unit 28 and (if necessary) oxidizer from the oxidizer supply unit 26 to the duct burner 24, thereby stopping or reducing combustion in or upstream of the HRSG 16. Generally, the thermal control system 22 (e.g., controlled by the control device 220) is configured to change the flow of fuel and oxidizer (if necessary) to increase or decrease combustion and heat addition to the exhaust gas so that the temperature of the exhaust gas is maintained at or above the temperature threshold (or between the upper and lower temperature thresholds). The thermal control system 22 (for example, controlled by the control device 220) may also include sensor feedback and control based on the oxygen content of the exhaust gas 152, the operation of the EGR system 150, and the operation of the gas treatment system 18.

[0040] While the duct burner 24 is operating (for example, when fuel is supplied from the fuel supply unit 28 for temperature control), the thermal control system 22 (for example, controlled by the control device 220) may selectively operate the oxidizer supply unit 26 (if necessary) to promote the combustion of the fuel supplied by the fuel supply unit 28. In certain embodiments, one or more sensors 222 (for example, oxygen sensors) are coupled to the HRSG 16 and / or the upstream duct piping of the HRSG 16, the duct burner 24 or its upstream side, or any combination thereof, to monitor the oxygen content of the exhaust gas 152. While the duct burner 24 is operating, if the oxygen content of the exhaust gas 152 falls below an oxygen threshold (for example, a lower oxygen threshold), the thermal control system 22 (for example, controlled by the control device 220) is configured to supply oxidizer from the oxidizer supply unit 26 to increase the oxygen content of the exhaust gas 152. If the oxygen content of the exhaust gas 152 is greater than or equal to an oxygen threshold (e.g., a lower oxygen threshold) or between the upper and lower oxygen thresholds, the thermal control system 22 (e.g., controlled by a control device 220) is configured to stop or reduce the supply of oxidizer from the oxidizer supply unit 26 to reduce the oxygen content of the exhaust gas 152. In certain embodiments, the lower oxygen threshold may be about 10, 11, or 12 (plus or minus 0.5) volume percent of oxygen in the exhaust gas 152. In some embodiments, the lower oxygen threshold may be about 10.5 (plus or minus 0.1, 0.2, 0.3, 0.4, or 0.5) volume percent of oxygen in the exhaust gas 152. In some embodiments, the lower and upper oxygen thresholds may define 10-11, 10-12, 10-13, 10-14, or 10-15 volume percent of oxygen in the exhaust gas 152. Sensor 222 (e.g., an oxygen sensor) can monitor changes in the oxygen content of the exhaust gas 152 in response to adjustments to the oxidizer supply unit 26, and as a result, the thermal control system 22 can increase or decrease the flow of oxidizer from the oxidizer supply unit 26 based on oxygen thresholds (e.g., a lower oxygen threshold, or both an upper and lower oxygen threshold).For example, the thermal control system 22 (controlled by, for example, the control device 220) may continuously or periodically (for example, in seconds or minutes) adjust the oxidizer supply unit 26 to increase or decrease the flow of oxidizer from the oxidizer supply unit 26 so that the oxygen content is at or slightly above an oxygen threshold (e.g., a lower oxygen threshold) or between an upper and lower oxygen threshold. In certain embodiments, the oxygen threshold may be a preset (e.g., fixed) oxygen threshold, such as a preset lower oxygen threshold or preset upper and lower oxygen thresholds. In some embodiments, the oxygen threshold may be variable based on operating conditions such as fuel characteristics, variable fuel flow rate, or a combination thereof. For example, the oxygen threshold may be variable based on a desired oxidizer-fuel ratio (e.g., air-fuel ratio) and fuel flow rate, and the thermal control system 22 may be configured to change both the fuel flow and the oxidizer flow based on the desired oxidizer-fuel ratio. However, the thermal control system 22 is configured to adjust the oxidizer supply unit 26 and the fuel supply unit 28 in various ways based on the oxygen content, one or more oxygen thresholds, the exhaust gas temperature, and other operating conditions for providing the desired heat addition to the exhaust gas 152.

[0041] Additionally or alternatively, the thermal control system 22 (e.g., controlled by the control device 220) may be configured to start, increase, stop, and / or decrease the flow of fuel and oxidizer (if necessary) to increase or decrease combustion and heat addition to the exhaust gas, depending on the operating mode of the gas turbine system 12, such as EGR mode in which the EGR system 150 recirculates the exhaust gas to the gas turbine system 12, or non-EGR mode in which the EGR system 150 does not recirculate the exhaust gas to the gas turbine system 12. In EGR mode, the oxygen content of the exhaust gas 152 is generally lower compared to non-EGR mode. In addition, in EGR mode, the rate of EGR recirculation affects the oxygen content in the exhaust gas 152. In certain embodiments, the rate of EGR recirculation may vary in the range of 5-50% or 10-40%. During EGR mode, if the temperature of the exhaust gas 152 falls below a lower temperature threshold, the thermal control system 22 (e.g., controlled by the control device 220) may be configured to operate the duct burner 24 to add heat and adjust the flow of fuel and oxidizer, at least partially based on the rate of EGR recirculation, to help raise the temperature of the exhaust gas 152. For example, if the EGR system 150 increases the rate of EGR flow through the gas turbine system 12 (e.g., the rate of EGR relative to the total output of exhaust gas 152) while the duct burner 24 is operating, the thermal control system 22 may selectively start and / or increase the flow of oxidizer from the oxidizer supply unit 26 to the duct burner 24, thereby increasing the oxygen content of the exhaust gas 152 and compensating for the decrease in the oxygen content of the exhaust gas 152 that occurs with the increase in EGR. As another example, if the EGR system 150 reduces the proportion of EGR flowing through the gas turbine system 12 (e.g., the proportion of EGR to the total output of exhaust gas 152) while the duct burner 24 is operating, the thermal control system 22 can selectively stop and / or reduce the flow of oxidizer from the oxidizer supply unit 26 to the duct burner 24, thereby reducing the oxygen content of the exhaust gas 152 and compensating for the increase in the oxygen content of the exhaust gas 152 that occurs with the reduction in EGR.As described above, the thermal control system 22 may be configured to adjust the oxidizer supply unit 26 to achieve an oxygen content at or above an oxygen threshold (e.g., a lower oxygen threshold) or between an upper and lower oxygen threshold. For example, if the EGR results in a volume percentage reduction of at least 1, 2, 3, 4, 5, 6, 7 or more (or at least a percentage below the lower oxygen threshold) of oxygen in the exhaust gas 152, the oxidizer supply unit 26 increases the oxygen content in the exhaust gas 152 by adding 1, 2, 3, 4, 5, 6, 7 or more volume percentages (or more) of oxygen to the exhaust gas 152. In some embodiments, the adjustment to the oxidizer supply unit 26 may be based on the EGR rate and / or other operating conditions. For example, the thermal control system 22 (e.g., via the control device 220) may use a lookup table, a computer model of the combined cycle system 10, or another correlation between the EGR rate and the oxidizer flow to determine an appropriate flow rate of oxidizer from the oxidizer supply unit 26 to the duct burner 24.

[0042] The oxidizer supply unit 26 may include one or more oxidizer supply units, which may be the same or different from each other. For example, the oxidizer supply unit 26 may include one or more of the ejector systems 240 and compression systems 242 configured to supply an oxidizer 244 to the duct burner 24. The oxidizer 244 may include any suitable oxidizer, such as air, oxygen, oxygen-enriched air, oxygen-reduced air, oxygen-containing gas, or any combination thereof. Each ejector system 240 may include an ejector 246 coupled to a drive unit 248, which takes the flow of oxidizer 244 into a power fluid 250 (e.g., power gas), such as a compressor extraction gas (e.g., EGR gas) 252. Each compression system 242 may include a compressor 254 coupled to a drive unit 256. The control device 220 is coupled to the drive units 248 and 256 to change the flow of oxidizer 244 to the duct burner 24 based on various operating parameters such as the temperature of the exhaust gas 152, the oxygen content in the exhaust gas 152, the operating mode of the combined cycle system 10 (e.g., EGR mode or non-EGR mode), and / or other operating parameters as described above.

[0043] In the illustrated embodiment, the ejector 246 is a variable ejector (e.g., a variable shape ejector or variable flow ejector) configured to change one or more flow paths (e.g., cross-sectional flow regions) through the ejector 246 via control of a drive unit 248. For example, the drive unit 248 may be configured to move a valve to partially open and close the flow path of the oxidizer 244, and / or the drive unit 248 may be configured to move a valve to partially open and close the flow path of the power fluid 250. Thus, the ejector 246 provides a variable flow of the oxidizer 244 via control of the drive unit 248 by the control device 220. In certain embodiments, the drive unit 248 may include an electric drive (e.g., an electric motor) and / or a fluid drive (e.g., a hydraulic drive and / or a pneumatic drive). In some embodiments, the ejector 246 may omit the drive unit 248, and the ejector 246 may have a fixed shape (e.g., an invariant flow path) for the oxidizer 244 and the power fluid 250.

[0044] During operation, the ejector 246 is configured to draw the oxidizer 244 into the power fluid 250 (e.g., power gas), and the ejector 246 outputs the oxidizer fluid mixture for supply to the duct burner 24. The power fluid 250 has a higher pressure and / or flow rate than the oxidizer 244, thereby providing energy for drawing in the oxidizer 244. For example, the power fluid 250 may be compressed to a pressure well above atmospheric pressure, while the oxidizer 244 may be approximately at atmospheric pressure. In certain embodiments, the power fluid 250 includes compressed gas from the compressor section 42 of the gas turbine system 12, compressed gas from the compressor system 106, compressed gas from the compression system 206 (e.g., capture gas 204), compressed gas from another compressor, high-pressure gas from another combustion system (e.g., exhaust gas, EGR gas), or any combination thereof. For example, the power fluid 250 may include compressor extraction gas as compressed gas from one or more of the above compressors. The compressor bleed gas may include compressed exhaust gas, such as compressed EGR gas. In the illustrated embodiment, the power fluid 250 may include compressor bleed gas (e.g., EGR gas) 252 from the compressor section 42. As described above, the compressor section 42 may include a plurality of compressor stages 58, and the compressor bleed gas 252 is extracted from one or more compressor bleed ports between the compressor stages 58. For example, in an embodiment having at least 10, 20, or 30 compressor stages 58, the compressor bleed gas 252 may be extracted from any one or more compressor bleed ports of each compressor stage 58 or downstream thereof, or of one or more selected compressor stages 58.

[0045] In certain embodiments, the power fluid 250 may or may not contain oxygen, air, or other oxygen-containing gases. For example, the power fluid 250 may have an oxygen content of 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 volume percent or less. In some embodiments, the power fluid 250 includes an inert gas and / or captured gas 204 (e.g., CO2) from the gas capture system 20. The power fluid 250 (e.g., EGR gas) has a higher pressure than the oxidizer 244, which may contain atmospheric air. In some embodiments, the power fluid 250 includes EGR gas (e.g., recirculated from exhaust gas 152) resulting from stoichiometric combustion, fuel-rich combustion, or fuel-lean combustion in the combustor section 44 of the gas turbine system 12. One measure of stoichiometric combustion is the equivalence ratio or phi (φ), which is the ratio of the actual fuel / oxidizer ratio to the stoichiometric fuel / oxidizer ratio. When the equivalence ratio exceeds 1.0, fuel-rich combustion of the fuel and oxidizer occurs, and when the equivalence ratio is less than 1.0, fuel-lean combustion of the fuel and oxidizer occurs. In contrast, at an equivalence ratio of 1.0, combustion occurs that is neither fuel-rich nor fuel-lean, thereby consuming substantially all of the fuel and oxidizer in the combustion reaction. In the context of the disclosed embodiments, the terms stoichiometric or substantially stoichiometric may refer to equivalence ratios of about 0.95 to about 1.05. However, the disclosed embodiments may also include equivalence ratios of 1.0 plus or minus 0.01, 0.02, 0.03, 0.04, 0.05 or greater. Again, stoichiometric combustion of the fuel and oxidizer in the combustor section 44 may produce combustion or exhaust gas 152 products with substantially no unburned fuel or oxidizer remaining. For example, exhaust gas 152 may contain less than 1, 2, 3, 4, or 5 percent of oxidizer (e.g., oxygen) and / or unburned fuel relative to the volume of exhaust gas 152, or exhaust gas 152 may contain less than approximately 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500, 1000, 2000, 3000, 4000, or 5000 volume ppm (ppmv) of oxidizer (e.g., oxygen) and / or unburned fuel in the exhaust gas 152.In some embodiments, the exhaust gas 152 (and therefore the EGR gas used in the power fluid 250) may contain some residual oxidants by having an equivalent ratio of less than 1 (e.g., less than 0.95), or the exhaust gas 152 (and therefore the EGR gas used in the power fluid 250) may contain some unburned fuel by having an equivalent ratio greater than 1 (e.g., greater than 1.05).

[0046] The oxidizer supply unit 26 may include one or more components of a compression system 242 having a compressor 254 coupled to a drive unit 256. The compressor 254 may include an axial flow compressor, a centrifugal compressor, a rotary screw compressor, a rotary vane compressor, a reciprocating piston compressor, or any combination thereof. The drive unit 256 may include a steam turbine, an electric drive unit (e.g., an electric motor), a reciprocating engine (e.g., a reciprocating piston cylinder internal combustion engine), a gas turbine, a hydraulic turbine, a wind turbine, or any combination thereof. For example, a steam turbine may include a steam turbine system 14 and / or an independent steam turbine. As a further example, a gas turbine may include a gas turbine system 12 and / or an independent gas turbine. In some embodiments, the drive unit 256 includes a waste heat recovery turbine driven by a heating fluid having waste heat from another heat system in the combined cycle system 10.

[0047] As described above, the duct burner 24 selectively heats the exhaust gas 152 flowing through the HRSG 16 by combustion to regulate its temperature. When in operation, the duct burner 24 receives fuel from the fuel supply unit 28 and, if necessary, oxidizer from the oxidizer supply unit 26, including one of the examples of the oxidizer supply unit 26 described above (e.g., the ejector system 240 and / or the compression system 242). In addition, the fuel supply unit 28 may include one or more of the following: a fuel tank, a fuel pump, a fuel valve, a fuel pressure regulator, a fuel filter, a fuel supply conduit, or any combination thereof. The duct burner 24 may be positioned at any suitable location relative to sections 160, 162, and 164 of the HRSG 16, such as upstream of one or more of the sections 160, 162, and 164 (e.g., all of them). In certain embodiments, the duct burner 24 may be positioned downstream of one or more components 258 and 260 of the HRSG 16. For example, components 258 and 260 may include a reheater and a superheater (e.g., a high-pressure superheater), respectively. Thus, in certain embodiments, the duct burners 24 may be partially positioned between components and / or sections of the HRSG 16. In some embodiments, multiple duct burners 24 may be distributed throughout the HRSG 16 and / or at various locations or sections upstream of the HRSG 16.

[0048] Figure 2 is a schematic diagram of one embodiment of the combined cycle system 10 of Figure 1, showing one embodiment of a thermal control system 22 having a plurality of oxidizer supply units 26 coupled to a duct burner 24 in the HRSG 16 and a fuel supply unit 28 of a fluid supply system 25. The thermal control system 22 is substantially the same as that described in detail above with reference to Figure 1. Accordingly, the components and functions of the thermal control system 22, including control by the control device 220, are the same as those described above unless otherwise specified. In the illustrated embodiment, the duct burner 24 is located in the HRSG 16 (e.g., in the housing or duct 280 of the HRSG 16) between components 258 and 260 (e.g., reheater and superheater) and sections 160, 162, and 164; however, the duct burner 24 may be located at any suitable location within the duct 280 of the HRSG 16. The duct burner 24 is fluidly coupled to the fuel supply unit 28 via a fuel circuit 282 and to the oxidizer supply unit 26 via one or more oxidizer circuits 284. Circuits 282 and 284 include one or more fluid conduits, manifolds, valves, and flow distribution networks. In the illustrated embodiment, the oxidizer supply unit 26 includes an ejector system 240 and a plurality of compression systems 242, including compression systems 286 and 288. However, the illustrated oxidizer supply unit 26 is merely an example of the oxidizer supply unit 26 described above with reference to Figure 1, and therefore any number and configuration of ejector systems 240 and compression systems 242 can be part of the thermal control system 22.

[0049] The duct burner 24 may include various configurations for burning fuel from the fuel supply unit 28 with oxygen in the exhaust gas 152 and / or oxidizer (if necessary) from the oxidizer supply unit 26. In some embodiments, the duct burner 24 includes separate injection grids for the oxidizer and fuel from the respective oxidizer supply unit 26 and fuel supply unit 28. For example, the duct burner 24 may include an oxidizer injection grid located axially upstream and separate from the fuel injection grid. However, in some embodiments, the duct burner 24 may integrate the oxidizer and fuel injection grids into a single injection structure. For example, as shown in Figure 2, the duct burner 24 may include an injection grid 290 having a plurality of injection conduits 292 that extend across the duct 24 along the longitudinal axis of the duct 24, intersecting (e.g., perpendicular to) the exhaust passage 294. The injection grid 290 may include conduits 292 arranged parallel to each other, intersecting each other, or in a combination thereof. The conduit 292 may also include a plurality of oxidizer ports 296 and a plurality of fuel ports 298 distributed across the duct 280 within the injection grid 290. In some embodiments, the oxidizer ports 296 are located upstream of the fuel ports 298, on their own, and / or downstream. In addition, in some embodiments, the oxidizer ports 296 and fuel ports 298 may be arranged side by side, coaxially or concentrically with respect to each other, or in any combination thereof. In some embodiments, the oxidizer supply unit 26 and the fuel supply unit 28 may mix the fuel and oxidizer at least partially or completely inside the injection grid 290 (e.g., within the conduit 292), in the mixing chamber, or in any combination thereof. However, in the illustrated embodiment, the oxidizer and fuel are injected separately through their respective oxidizer ports 296 and fuel ports 298. The conduit 292 may include cylindrical conduits, wing-shaped conduits, tapered conduits, or any combination thereof.

[0050] The ejector system 240 includes an ejector 246 coupled to a drive unit 248, the ejector 246 configured to take in an oxidizer 244 into the power fluid 250 using compressor bleed gas (e.g., EGR gas) 252 from the gas turbine system 12. As described above, the compressor bleed gas 252 may include EGR gas if the gas turbine system 12 is operating in EGR mode. The gas turbine system 12 operates in EGR mode via the EGR system 150, recirculating a portion of the exhaust gas 152 as EGR gas 300. The EGR gas 300 flows throughout the gas turbine system 12, including the compressor section 42, the combustor section 44, and the turbine section 46, as described above. However, a portion of the EGR gas 300 may be extracted or bled from the gas turbine system 12, for example, through one or more ports 302 (e.g., extraction ports or bleed ports). The illustrated port 302 is coupled to the compressor section 42; however, port 302 may be coupled to the compressor discharge casing or to another location in the gas turbine system 12. Thus, port 302 allows a portion of the EGR gas 300 that has passed through one or more compression stages 58 in the compressor section 42 to be extracted as compressor bleed gas (e.g., EGR gas) 252 and used as the power fluid 250 for the ejector system 240. Port 302 may also be coupled to the ejector system 240 via a compressor bleed circuit 304, which may include one or more fluid conduits, valves, manifolds, and flow distribution devices.

[0051] In the illustrated embodiment, the ejector 246 includes an ejector body 306 having a fluid intake body portion 308 and a fluid mixing body portion 310. The fluid intake body portion 308 includes a power fluid intake passage 312, an oxidizer intake passage 314, a wall 316 separating the power fluid intake passage 312 and the oxidizer intake passage 314, and a power fluid nozzle 318 that penetrates the wall 316 and protrudes into the oxidizer intake passage 314 toward the fluid mixing body portion 310. For example, the power fluid nozzle 318 may be coaxial with the longitudinal axis 320 of the ejector 246 and the fluid mixing body portion 310. In the illustrated embodiment, the power fluid intake passage 312 and the oxidizer intake passage 314 are oriented intersecting the longitudinal axis 320 of the ejector 246. The fluid mixing body portion 310 includes a mixing flow passage 322 from the fluid intake body portion 308 of the ejector 246 to the fluid outlet 324, the cross-sectional area of ​​which changes. The mixing flow passage 322 and the fluid outlet 324 may be coaxial with the longitudinal axis 320. In certain embodiments, the mixing flow passage 322 includes a converging flow passage 326, a throat 328, and a diffusion flow passage 330 in the flow direction from the fluid intake body portion 308 through the ejector 246 to the fluid outlet 324 of the ejector 246. In the illustrated embodiments, the mixing flow passage 322 is an annular flow passage, the converging flow passage 326 is a converging annular flow passage (e.g., a frustoconical or curved annular flow passage), the throat 328 is a cylindrical flow passage, and the diffusion flow passage 330 is a diffusion annular flow passage (e.g., a frustoconical or curved annular flow passage).

[0052] During operation, the ejector system 240 delivers power fluid 250 (e.g., compressor extraction gas 252) from the power fluid intake passage 312 through the power fluid nozzle 318 to the oxidizer intake passage 314, thereby drawing in, drawing in, or taking in the oxidizer 244 along with the power fluid 250 from the oxidizer intake passage 314 to the ejector 246. The oxidizer 244 and power fluid 250 are mixed in the mixing flow passage 322 and discharged as a mixed fluid (e.g., oxidizer-power fluid mixture) from the ejector 246 through the outlet 324. Again, the power fluid 250 has a higher pressure, higher flow rate, higher velocity, or a combination thereof relative to the oxidizer 244, thereby taking in the oxidizer 244 into the power fluid 250. The ejector 246 may include a fixed configuration, but the illustrated embodiment allows for variable flow via a drive unit 248 coupled to a valve 332. The valve 332 is coupled to a shaft 334 that passes through an annular seal 336, and the shaft 334 is coupled to a drive unit 248.

[0053] During operation, the control device 220 is configured to control the drive device 248 to move the valve 332 axially toward or away from the power fluid nozzle 318, thereby increasing or decreasing the flow cross-sectional area through the power fluid nozzle 318. For example, the drive device 248 may be configured to rotate the shaft 334 along a screw interface, thereby driving the shaft 334 and the valve 332 to move axially along the longitudinal axis 320. As a further example, the drive device 248 may be configured to translate the shaft 334 (e.g., axial movement without rotation), thereby driving the shaft 334 and the valve 332 to move axially along the longitudinal axis 320. The valve 332 may include an annular valve tip (e.g., a frustoconical valve tip) configured to partially extend into the mixing fluid nozzle 318, thereby partially blocking the flow path through the mixing fluid nozzle 318 and reducing the flow of power fluid 250 through the ejector 246. The change in the flow of the power fluid 250 then changes the flow of the oxidizer 244 through the ejector 246. Therefore, the control device 220 is configured to control the drive device 248 to change the flow of the oxidizer 244 for use in the duct burner 24, as described above.

[0054] The compression system 286 includes a compressor 340 coupled to a turbine 342 via a shaft 344. The compressor 340 and turbine 342 are examples of the compressor 254 and drive unit 256 of the compression system 242 described above with reference to Figure 1. The compressor 340 may include an axial flow compressor, a centrifugal compressor, a rotary screw compressor, a rotary vane compressor, or any combination thereof. The turbine 342 may include any type of fluid-driven turbine, such as a steam turbine, a gas turbine, a hydraulic turbine, a wind turbine, or any combination thereof. In the illustrated embodiment, the turbine 342 is a steam turbine driven by steam 346 from a steam supply unit 348. The steam 346 flows through the turbine 342 and expands, thereby forcing the turbine blades to rotate the shaft coupled to the shaft 344. The turbine 342 then discharges steam 350 into a steam circuit 352, which may include valves 354 that control the flow of steam 350 to other downstream equipment 356. In certain embodiments, the turbine 342 may be a back-pressure steam turbine configured to expand steam 346 to a pressure suitable for downstream equipment 356. The steam supply unit 348 may include a boiler or a steam generator. The steam supply unit 348 may include, or exclude, a heat recovery steam generator such as an HRSG 16. A compressor 340 driven by the turbine 342 receives and compresses the oxidizer 244 and outputs compressed oxidizer 358 for use in the duct burner 24. For example, the compressor 340 may be coupled to the duct burner 24 via the oxidizer circuit portion 360 of the oxidizer circuit 284. In certain embodiments, the turbine 342 may also be coupled to another load such as a generator 362 via a shaft 364. During operation, the thermal control system 22 (e.g., via a control device 220) may be configured to control the supply of compressed oxidizer 358 to the duct burner 24 via control of the steam supply unit 348, valves along the oxidizer circuit portion 360, or another flow control unit.The thermal control system 22 is configured to selectively supply the compressed oxidizer 358 to the duct burner 24 based on the temperature of the exhaust gas 152, the oxygen content in the exhaust gas 152, the operating mode of the combined cycle system 10 (e.g., EGR mode or non-EGR mode), the generation of the desired steam by the HRSG 16, the supply of the desired steam to the steam turbine system 14, or any combination thereof.

[0055] The compression system 288 includes a compressor 370 coupled to an electric drive unit 372 via a shaft 374. The compressor 370 and electric drive unit 372 are examples of the compressor 254 and drive unit 256 of the compression system 242 described above with reference to Figure 1. The compressor 370 may include an axial flow compressor, a centrifugal compressor, a rotary screw compressor, a rotary vane compressor, or any combination thereof. The electric drive unit 372 may include an electric motor such as an AC motor or a DC motor. Driven by the electric drive unit 372, the compressor 370 receives and compresses the oxidizer 244 and outputs a compressed oxidizer 376 for use in the duct burner 24. For example, the compressor 370 may be coupled to the duct burner 24 via the oxidizer circuit portion 378 of the oxidizer circuit 284. During operation, the thermal control system 22 (e.g., via the control device 220) may be configured to control the supply of compressed oxidant 376 to the duct burner 24 via the electric drive 372. The thermal control system 22 is configured to selectively supply compressed oxidant 376 to the duct burner 24 based on the temperature of the exhaust gas 152, the oxygen content in the exhaust gas 152, the operating mode of the combined cycle system 10 (e.g., EGR mode or non-EGR mode), the generation of desired steam by the HRSG 16, the supply of desired steam to the steam turbine system 14, or any combination thereof.

[0056] Figure 3 is a flowchart of one embodiment of process 400 for operating the combined cycle system 10 of Figures 1-2, and shows the control logic for operating the thermal control system 22. Process 400 may be performed by the processor 224 of the control unit 220 and / or one or more additional control units, processors, and / or computers. Process 400 includes operating a heat recovery steam generator (HRSG) 16 downstream of the gas turbine system 12 (block 402). Process 400 includes controlling the gas turbine system 12 in exhaust gas recirculation (EGR) mode or non-EGR mode as an operating mode (block 404). EGR mode includes controlling an EGR system 150 to recirculate at least a portion of the exhaust gas 152 as an EGR flow to the compressor section 42. In non-EGR mode, process 400 may selectively disable the EGR system 150, or the EGR system 150 may be excluded from the gas turbine system 12. When operating in EGR mode, process 400 may include adjusting the EGR flow via an EGR system 150 coupled to the gas turbine system 12 (block 406). Adjusting the EGR flow (block 406) includes increasing or decreasing the rate or ratio of exhaust gas 152 recirculated to the compressor section 42. As described above, increasing the EGR flow may result in a decrease in the oxygen content in the exhaust gas 152. Conversely, decreasing the EGR flow may result in an increase in the oxygen content in the exhaust gas 152. Therefore, process 400 may also include monitoring the EGR flow, the temperature of the exhaust gas 152 into the HRSG 16, and the oxygen content of the exhaust gas 152 into the HRSG 16 via one or more sensors 222 (block 408). Process 400 then uses the monitored information to control the thermal control system 22.

[0057] For example, process 400 includes comparing the temperature of exhaust gas 152 against one or more temperature thresholds for the operation of HRSG 16 (e.g., a lower temperature threshold, or both an upper and lower temperature threshold) and obtaining a temperature comparison (block 410). The lower temperature threshold may be the lowest temperature suitable for obtaining the desired heat transfer and steam generation in HRSG 16. Similarly, the upper and lower temperature thresholds may be set to achieve the desired steam generation by HRSG 16, and the upper and lower temperature thresholds may be based on the operating thresholds of the steam turbine system 14. Process 400 may also include comparing the oxidizer content of exhaust gas 152 against one or more oxygen thresholds for the operation of duct burner 24 (e.g., a lower oxygen threshold, or both an upper and lower oxygen threshold) and obtaining an oxygen comparison (block 412). The lower oxygen threshold may be the minimum oxygen content suitable for burning fuel from fuel supply unit 28. In certain embodiments, the upper and lower oxygen thresholds may be fixed or variable depending on the type of fuel, the desired oxidizer-fuel ratio (e.g., air-fuel ratio), and the fuel flow rate. Process 400 may also include comparing the EGR flow through the EGR system 150 to the correlation between the EGR flow and oxidizer increase in the duct burner 24 to obtain an EGR comparison (block 414). The correlation between the EGR flow and oxidizer increase may be defined by a lookup table, a computer model, an equation, a control curve, or any combination thereof, and any particular EGR flow value and corresponding oxidizer supply value may be determined by process 400. Each of the comparisons described above in blocks 410, 412, and 414 can be used by process 400 for the control of the thermal control system 22.

[0058] Process 400 may include controlling a fuel supply unit 28 coupled to a duct burner 24 based on a temperature comparison (block 416). For example, if the temperature comparison indicates that the temperature of the exhaust gas 152 is below a temperature threshold (e.g., a lower temperature threshold), process 400 may start and / or increase the fuel flow from the fuel supply unit 28 to the duct burner 24 to help raise the temperature of the exhaust gas 152. If the temperature comparison indicates that the temperature of the exhaust gas 152 is above a temperature threshold (e.g., a lower temperature threshold), process 400 may stop and / or decrease the fuel flow from the fuel supply unit 28 to the duct burner 24 to help lower the temperature of the exhaust gas 152. If upper and lower temperature thresholds are used for control, process 400 may adjust (e.g., start, stop, increase, or decrease) the fuel flow from the fuel supply unit 28 to the duct burner 24 to change the temperature of the exhaust gas 152 to help maintain the temperature between the upper and lower temperature thresholds.

[0059] Process 400 may also include controlling the oxidizer supply unit 26 coupled to the duct burner 24 based on oxygen comparison and / or EGR comparison (block 418). For example, if the oxygen comparison indicates that the oxygen content of the exhaust gas 152 is below an oxygen threshold (e.g., a lower oxygen threshold), process 400 may start and / or increase the flow of oxidizer from the oxidizer supply unit 26 to the duct burner 24 to help increase the oxygen content of the exhaust gas 152. If the oxygen comparison indicates that the oxygen content of the exhaust gas 152 is above an oxygen threshold (e.g., a lower oxygen threshold), process 400 may stop and / or decrease the flow of oxidizer from the oxidizer supply unit 26 to the duct burner 24 to help decrease the oxygen content of the exhaust gas 152. When upper and lower oxygen thresholds are used for control, process 400 may adjust (e.g., start, stop, increase, or decrease) the flow of oxidant from the oxidant supply unit 26 to the duct burner 24 to change the oxygen content of the exhaust gas 152, thereby helping to maintain the oxygen content between the upper and lower oxygen thresholds. As a further example, if a specific oxidant supply target is indicated by an EGR comparison, process 400 may control (e.g., start, stop, increase, or decrease) the oxidant supply unit 26 to supply the corresponding flow of oxidant to the duct burner 24. Process 400 may control the oxidant supply unit 26 based on oxygen comparison only, EGR comparison only, both oxygen comparison and EGR comparison, and / or other control parameters.

[0060] Process 400 further controls a gas processing system 18, which includes one or more gas capture systems 20, to acquire captured gas 204 downstream of the HRSG 16. Process 400 coordinates the control of the gas turbine system 12, the steam turbine system 14, the HRSG 16, the gas processing system 18 (and gas capture systems 20), and the thermal control system 22. Thus, the oxidizer supply unit 26 is selectively controlled in conjunction with the control of the fuel supply unit 28, thereby supplying any additional heat required via the duct burner 24. Thus, the oxidizer supply unit 26 can provide increased oxidizer when needed for the operation of the duct burner 24.

[0061] Figure 4 is a flowchart of one embodiment of process 430 for operating the combined cycle system 10 of Figures 1-2, and shows the control logic for operating the thermal control system 22. Process 430 may be performed by the processor 224 of the control unit 220 and / or one or more additional control units, processors, and / or computers. Process 430 includes monitoring the oxygen (O2) content of the exhaust gas 152 via one or more sensors 222 (block 432). Process 430 then uses the monitored information to control the thermal control system 22. For example, process 430 includes monitoring the EGR state of the EGR system 150, in particular whether the EGR system 150 is on or operating in EGR mode, or off or in non-EGR mode (block 434). If the EGR system 150 is off (i.e., in non-EGR mode), process 430 may not perform any further operations (block 436). In other words, process 430 does not need to operate the oxidizer supply unit 26 when the EGR system 150 is off (i.e., in non-EGR mode). When the EGR system 150 is on (i.e., in EGR mode), process 430 may monitor the state of the duct burner 24, i.e., whether the duct burner 24 is on or off (block 438).

[0062] If the duct burner 24 is in the off state, process 430 does not need to perform any further operations (block 436). In other words, process 430 does not need to operate the oxidizer supply unit 26 when the duct burner 24 is off (i.e., in the off state). However, if the duct burner 24 is on (i.e., in the on state), process 430 may evaluate the oxygen content (O2%) relative to a threshold, for example, a lower oxygen threshold (block 440). In some embodiments, the lower oxygen threshold may be 10.5 volume percent of oxygen in the exhaust gas. However, the lower oxygen threshold may be any value from 10 to 15 in units of 0.1, and the lower oxygen threshold represents the volume percentage of oxygen in the exhaust gas. If the oxygen content (O2%) is greater than the oxygen threshold, process 430 does not need to perform any further operations (block 436). In other words, the oxidizer supply unit 26 is not necessary for oxygen increase. However, if the oxygen content (O2%) is below the oxygen threshold, process 430 may activate the oxidizer supply unit 26 to increase the oxygen content (block 442). Process 430 continuously loops through blocks 432 to 442, thereby continuously adjusting the oxygen content necessary to facilitate the operation of the duct burner 24 when operating the EGR and when operating the duct burner 24. Thus, the oxidizer supply unit 26 provides increased oxidizer (e.g., increased O2) as needed during the operation of the EGR and duct burner.

[0063] The technical effects of the invention include a system and method for thermal control in an HRSG 16 using a duct burner 24 coupled to an oxidizer supply unit 26 and a fuel supply unit 28 of a thermal control system 22, the HRSG 16 receiving exhaust gas 152 which may have an insufficient oxygen content for the operation of the duct burner 24. For example, the operation of the EGR system 150 may result in an insufficient oxygen content, and as a result, the duct burner 24 cannot operate without an increase in oxidizer by the oxidizer supply unit 26. The oxidizer supply unit 26 may include an ejector system 240 and / or a compression system 242 for selectively supplying oxidizer into the duct burner 24. The ejector system 240 is advantageous in that it uses an existing fluid, such as compressor extraction gas (e.g., EGR flow) 252 from a compression section 42, thereby supplying oxidizer into the duct burner 24 using an existing energy source. The ejector system 240 has a relatively small footprint and has minimal or no moving parts. The compression system 242 may use an existing power source and / or an independent system within the combined cycle system 10 as the drive unit 256 for the compressor 254. In certain embodiments, the drive unit 256 may include a steam turbine, an electric motor, or another suitable drive unit. The thermal control system 22 may selectively use one or more of the ejector system 240 and the compression system 242 to supply oxidant to the duct burner 24. As a result, the duct burner 24 can support the HRSG 16 by adding heat when needed, even when the oxygen content of the exhaust gas 152 falls below the oxygen threshold due to the EGR flow.

[0064] The subject matter described in detail above may be defined by one or more clauses, as described below.

[0065] The system includes a duct burner configured to add combustion heat to exhaust gases led through a heat recovery steam generator (HRSG), a fuel supply unit configured to supply fuel to the duct burner, and an oxidizer supply unit configured to supply an oxidizer to the duct burner. The system also includes a control device having a memory, a processor, and instructions stored in the memory, which are executable by the processor, to control the fuel supply unit to supply fuel to the duct burner, and to control the oxidizer supply unit to supply an oxidizer to the duct burner, the control of the oxidizer supply unit being based on a comparison of the oxygen content in the exhaust gas with an oxygen threshold.

[0066] The control device is configured to receive feedback indicating the oxygen content in the exhaust gas, compare the oxygen content to an oxygen threshold to obtain a comparison, and if the oxygen content is less than the oxygen threshold, to increase the oxygen content by starting or increasing the flow of oxidizer from the oxidizer supply unit.

[0067] A control device configured to reduce the oxygen content by stopping or reducing the flow of oxidizer from an oxidizer supply unit when the oxygen content is above an oxygen threshold, as per any preceding clause.

[0068] A control device configured to control an oxidizer supply unit in at least a first control mode to initiate or increase the flow of oxidizer to a duct burner, wherein the first control mode includes an exhaust gas recirculation (EGR) control mode, as per any preceding clause.

[0069] A control device configured to control the oxidizer supply unit in at least a second control mode to stop or reduce the flow of oxidizer to the duct burner, wherein the second control mode includes a non-EGR control mode, as per any preceding clause.

[0070] A system of any prior clause, comprising an HRSG, a gas turbine system located upstream of the HRSG, and an exhaust gas recirculation (EGR) system configured to recirculate at least a portion of the exhaust gas to the gas turbine system.

[0071] A system of any prior clause, including a gas treatment system configured to treat exhaust gases, wherein the gas treatment system includes a gas capture system configured to capture gases from the exhaust gases.

[0072] The gas capture system includes a carbon capture system, and the gas includes carbon dioxide (CO2), as per any prior clause.

[0073] The oxidizer supply unit is a system of any prior clauses, including an ejector configured to supply an oxidizer via a power fluid.

[0074] The ejector includes a variable ejector having a drive unit coupled to a variable nozzle, the drive unit being configured to adjust the cross-section of the variable nozzle, and the variable nozzle being configured to flow a power fluid, as a system of any preceding clause.

[0075] The ejector is a system of any prior clauses including an oxidizer inlet, a power fluid inlet, a convergence passage, a throat, and a diffusion passage.

[0076] The power fluid includes a compressor bleed flow from a compressor of a gas turbine system configured to output exhaust gases, the compressor bleed flow includes exhaust gas recirculation (EGR) compressed by the compressor, and the oxidizer includes air, as per any preceding clause.

[0077] The oxidizer supply unit is a system of any prior clauses, including a compressor driven by a steam turbine.

[0078] The oxidizer supply unit is a system of any prior clauses, including a compressor driven by an electric motor.

[0079] A duct burner is a system of any prior clauses including an injection grid having multiple fuel ports and multiple oxidizer ports.

[0080] The system includes a control device having memory, a processor, and instructions stored in memory, which are executable by the processor and control a fuel supply unit to supply fuel to a duct burner of a heat recovery steam generator (HRSG), the duct burner being configured to add combustion heat to the exhaust gases led through the HRSG. The control device is also configured to control an oxidizer supply unit to supply an oxidizer to the duct burner, the control of which is based on a comparison of the oxygen content in the exhaust gases with an oxygen threshold.

[0081] The control device is configured to receive feedback indicating the oxygen content in the exhaust gas, compare the oxygen content to an oxygen threshold to obtain a comparison, and if the oxygen content is less than the oxygen threshold, to start or increase the flow of oxidizer from the oxidizer supply unit to increase the oxygen content, and if the oxygen content is equal to or greater than the oxygen threshold, to stop or decrease the flow of oxidizer from the oxidizer supply unit to decrease the oxygen content, as described in the preceding clause.

[0082] The control device is configured to control the oxidizer supply unit in at least a first control mode to start or increase the flow of oxidizer to the duct burner, the first control mode including an exhaust gas recirculation (EGR) control mode, as per any preceding clause. The control device is also configured to control the oxidizer supply unit in at least a second control mode to stop or reduce the flow of oxidizer to the duct burner, the second control mode including a non-EGR control mode.

[0083] The method includes controlling a fuel supply unit via a control device to supply fuel to a duct burner of a heat recovery steam generator (HRSG), wherein the duct burner is configured to add combustion heat to the exhaust gases guided through the HRSG. The method further includes controlling an oxidizer supply unit via a control device to supply an oxidizer to the duct burner, wherein the control of the oxidizer supply unit is based on a comparison of the oxygen content in the exhaust gases with an oxygen threshold.

[0084] The method of the preceding clause, which controls the oxidizer supply unit, includes receiving feedback indicating the oxygen content in the exhaust gas, comparing the oxygen content to an oxygen threshold and obtaining a comparison, increasing the oxygen content by starting or increasing the flow of oxidizer from the oxidizer supply unit if the oxygen content is less than the oxygen threshold, and decreasing the oxygen content by stopping or decreasing the flow of oxidizer from the oxidizer supply unit if the oxygen content is equal to or greater than the oxygen threshold.

[0085] This specification uses examples to disclose the invention in its best mode and to enable anyone skilled in the art to carry out the invention, including constructing and using any device or system and performing any incorporated method. The patentable scope of the invention is defined by the claims and may include other examples that a person skilled in the art could conceive. Such other examples are intended to be included in the claims if their structural elements are no different from the language of the claims, or if their structural elements are substantially equivalent and indistinguishable from the language of the claims. [Explanation of Symbols]

[0086] 10 Combined cycle system 12 Gas Turbine Systems 14 Steam Turbine System 16. Heat Recovery Steam Generator (HRSG) 18 Gas Processing System 20 Gas Capture Systems 22 Thermal control systems 24 Duct Burner 26 Oxidizing agent supply unit 28 Fuel supply section 30 axes 32 axes 34 axes 36 Rotation axis 40 Inhalation Sections 42 Compressor or compressor section 44 Combustor Section 46 Turbine Section 48 Exhaust Section 50 shaft 52 Casing 54 Rotary Compressor Blades 56 Fixed compressor vanes 58 Compressor Stages 60 Inhalation gas 62 Combustor 64 Head end section 66 Combustion section 68 Combustion Chamber 70 Combustor Liner 72 Flow Sleeve 74 aisles 76 Arrows 78 Head End Chamber 80 Intermediate Plate 82 Fuel Nozzle 84 End Plates 86 Compressed gas 88 Fuel System 90 Fuel supply system 92 Fuel circuit 94 Fuel circuit 96 Fuel circuit 98 Fuel circuit 100 components 104 Compressed air 106 Compressor System 108 Air compressor 110 Drive unit 112 High-temperature combustion gases 114 shaft 116 Casing 118 Rotary Turbine Blades 120 Fixed Turbine Vane 122 Turbine Stages 124 Intermediate shaft 126 load 128 shaft 150 EGR system 152 Exhaust gas 160 High-voltage section 162 Intermediate Pressure Section 164 Low-pressure section 166 High-pressure steam 168 Medium-pressure steam 170 Low-pressure steam 172 High-pressure steam turbine 174 Medium-pressure steam turbine 176 Low-pressure steam turbine 178 Shaft 180 load 182 Condensates 184 Exhaust gas 190 Gas Capture System 192 Gas Capture System 194 Gas Capture System 196 Components 198 Components 200 components 202 Components 204 Captured gas 206 Compression System 208 Storage / Pipeline 210 Components 212 Components 214 Components 220 Control device 222 Sensors 224 processors 226 memory 228 Command 230 Communication Circuit 240 Ejector System 242 Compression System 244 Oxidizing agent 246 Ejector 248 Drive unit 250 Power fluid 252 Compressor Extracted Gas 254 Compressor 256 Drive unit 258 components 260 components 280 duct 282 Fuel circuit 284 Oxidizer Cycle 286 Compression System 288 Compression System 290 injection grid 292 Injection conduit 294 Exhaust passage 296 Oxidizer Port 298 Fuel Ports 300 EGR gas Port 302 304 Compressor extraction circuit 306 Ejector Unit 308 Fluid suction main body part 310 Fluid mixing body part 312 Power fluid intake passage 314 Oxidizing agent inhalation passage 316 Wall 318 Power Fluid Nozzle 320 Longitudinal axis 322 Mixing flow passage 324 Fluid outlet 326 Converging flow path 328 Throat 330 Diffusion flow channel 332 Valves 334 shaft 336 Ring seal 340 Compressor 342 Turbine 344 shaft 346 Steam 348 Steam supply unit 350 steam 352 Steam Circuit 354 Valves 356 Equipment 358 Oxidizing agent 360 Oxidizer circuit section 362 Generators 364 shaft 370 Compressor 372 Electric drive system 374 shaft 376 Oxidizing agent 378 Oxidizer circuit section 400 processes 430 processes

Claims

1. It is a system, A duct burner (24) is configured to add heat from combustion to exhaust gas (184) that is guided through a heat recovery steam generator (HRSG) (16), A fuel supply unit (28) configured to supply fuel to the duct burner (24), An oxidizing agent supply unit (26) is configured to supply an oxidizing agent (244) to the duct burner (24), A control device (220), comprising a memory (226), a processor (224), and instructions stored in the memory (226), The fuel supply unit (28) is controlled to supply the fuel to the duct burner (24), The oxidant supply unit (26) is controlled to supply the oxidant (244) to the duct burner (24), and the control of the oxidant supply unit (26) is based on a comparison of the oxygen content in the exhaust gas (184) and the oxygen threshold. A control device (220) having instructions (228) that can be executed by the processor (224), A system that includes these features.

2. The control device (220) is Upon receiving feedback indicating the oxygen content in the exhaust gas (184), The comparison is obtained by comparing the oxygen content with respect to the oxygen threshold. If the oxygen content is less than the oxygen threshold, the flow of the oxidizing agent (244) from the oxidizing agent supply unit (26) is started or increased to increase the oxygen content. The system according to claim 1, configured as follows.

3. The control device (220) is If the oxygen content is above the oxygen threshold, the flow of the oxidizing agent (244) from the oxidizing agent supply unit (26) is stopped or reduced to reduce the oxygen content. The system according to claim 2, configured as follows.

4. The control device (220) is The oxidizer supply unit (26) is controlled in at least a first control mode to start or increase the flow of the oxidizer (244) to the duct burner (24), and the first control mode includes an exhaust gas recirculation (EGR) control mode. The system according to claim 1, configured as follows.

5. The control device (220) is The oxidizer supply unit (26) is controlled in at least a second control mode to stop or reduce the flow of the oxidizer (244) to the duct burner (24), the second control mode including a non-EGR control mode. The system according to claim 4, configured as described above.

6. The system according to claim 1, comprising: the HRSG (16); a gas turbine system (12) disposed upstream of the HRSG (16); and an exhaust gas recirculation (EGR) system configured to recirculate at least a portion of the exhaust gas (184) to the gas turbine system (12).

7. The system according to claim 6, comprising a gas treatment system (18) configured to treat the exhaust gas (184), wherein the gas treatment system (18) comprises a gas capture system (20) configured to capture gas from the exhaust gas (184).

8. The gas capture system (20) includes a carbon capture system, and the gas is carbon dioxide (CO2). ２ The system according to claim 7, including ).

9. The system according to claim 1, wherein the oxidizing agent supply unit (26) comprises an ejector (246) configured to supply the oxidizing agent (244) via a power fluid (250).

10. The system according to claim 9, wherein the ejector (246) comprises a variable ejector having a drive device coupled to a variable nozzle, the drive device being configured to adjust the cross-section of the variable nozzle, and the variable nozzle being configured to flow the power fluid (250).

11. The system according to claim 9, wherein the ejector (246) comprises an oxidizer inlet, a power fluid inlet, a convergence passage (326), a throat (328), and a diffusion passage (330).

12. The system according to claim 9, wherein the power fluid (250) includes a compressor bleed flow from a compressor (254) of a gas turbine system (12) configured to output the exhaust gas (184), the compressor bleed flow includes exhaust gas recirculation (EGR) compressed by the compressor (254), and the oxidizer (244) includes air.

13. The system according to claim 1, wherein the oxidizer supply unit (26) comprises a compressor (254) driven by a steam turbine.

14. The system according to claim 1, wherein the oxidizing agent supply unit (26) comprises a compressor (254) driven by an electric motor.

15. The system according to claim 1, wherein the duct burner (24) comprises an injection grid (290) having a plurality of fuel ports (298) and a plurality of oxidizer ports (296).

16. It is a system, A control device (220), comprising a memory (226), a processor (224), and instructions stored in the memory (226), The fuel supply unit (28) is controlled to supply fuel to the duct burner (24) of the heat recovery steam generator (HRSG) (16), and the duct burner (24) is configured to add heat from combustion to the exhaust gas (184) that is guided through the HRSG (16). The oxidizer supply unit (26) is controlled to supply the oxidizer (244) to the duct burner (24), and the control of the oxidizer supply unit (26) is based on a comparison of the oxygen content in the exhaust gas (184) and the oxygen threshold. A control device (220) having instructions (228) that can be executed by the processor (224), A system that includes these features.

17. The control device (220) is Upon receiving feedback indicating the oxygen content in the exhaust gas (184), The comparison is obtained by comparing the oxygen content with respect to the oxygen threshold. If the oxygen content is less than the oxygen threshold, the flow of the oxidizing agent (244) from the oxidizing agent supply unit (26) is started or increased to increase the oxygen content. If the oxygen content is above the oxygen threshold, the flow of the oxidizing agent (244) from the oxidizing agent supply unit (26) is stopped or reduced to reduce the oxygen content. The system according to claim 16, configured as described above.

18. The control device (220) is The oxidizer supply unit (26) is controlled in at least a first control mode to start or increase the flow of the oxidizer (244) to the duct burner (24), and the first control mode includes an exhaust gas recirculation (EGR) control mode. The oxidizer supply unit (26) is controlled in at least a second control mode to stop or reduce the flow of the oxidizer (244) to the duct burner (24), and the second control mode includes a non-EGR control mode. The system according to claim 16, configured as described above.

19. It is a method, The control device (220) controls the fuel supply unit (28) to supply fuel to the duct burner (24) of the heat recovery steam generator (HRSG) (16), wherein the duct burner (24) is configured to add heat from combustion to the exhaust gas (184) guided through the HRSG (16), The control device (220) controls the oxidizer supply unit (26) to supply the oxidizer (244) to the duct burner (24), wherein the control of the oxidizer supply unit (26) is based on a comparison between the oxygen content in the exhaust gas (184) and an oxygen threshold. Methods that include...

20. Controlling the oxidizing agent supply unit (26) means Receiving feedback indicating the oxygen content in the exhaust gas (184), The comparison is obtained by comparing the oxygen content with respect to the oxygen threshold, If the oxygen content is less than the oxygen threshold, the flow of the oxidizing agent (244) from the oxidizing agent supply unit (26) is started or increased to increase the oxygen content. If the oxygen content is above the oxygen threshold, the flow of the oxidizing agent (244) from the oxidizing agent supply unit (26) is stopped or reduced to decrease the oxygen content. The method according to claim 19, including the method described in claim 19.

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