Methods, and system for recirculating exhaust gases within combined cycle power plant

Abstract

A system, for recirculating exhaust gas includes a combined cycle power plant including a heat recovery steam generator (HRSG), a gas turbine system, and an exhaust gas recirculation assembly downstream from the HRSG for receiving the exhaust gas. The exhaust gas recirculation assembly includes a direct contact cooler (DCC) in flow communication with the gas turbine system. The system also includes a computing device(s) in communication with the power plant. The computing device(s) is configured to control the combined cycle power plant by performing processes including measuring a characteristic of the exhaust gas downstream from the exhaust gas recirculation assembly and comparing the measured characteristic of the exhaust gas to a predefined characteristic threshold or a predefined characteristic range for the exhaust gas. The computing device(s) also performs processes including adjusting operational parameters of the exhaust gas recirculation assembly, and / or a distinct portion of the combined cycle power plant.

Description

(17851-1457)METHODS, AND SYSTEM FOR RECIRCULATING EXHAUST GASES WITHINCOMBINED CYCLE POWER PLANTTECHNICAL FIELD

[0001] The disclosure relates generally to combined cycle power plants, and more particularly, to systems for recirculating exhaust gases into a turbine system of a combined cycle power plant.BACKGROUND

[0002] Combined cycle power plants typically include a heat recovery steam generator (HRSG) in in communication with a gas turbine system. The HRSG recovers or receives waste heat from the exhaust gases produced by the gas turbine system, converts a portion the heat to steam, and subsequently provides that steam to a steam turbine system of the power plant. In some systems, exhaust gases are released into the ambient environment after passing through the HRSG.

[0003] To address at least some of the inefficiencies associated with releasing the exhaust gases into the ambient environment, some power systems have incorporated exhaust gas recirculation. These conventional systems recirculate at least a portion of the exhaust gases back into the system for further processing. By recirculating the exhaust gas, such systems attempt to improve overall plant efficiency by utilizing the waste heat more effectively. However, while recirculating exhaust gas directly from the HRSG can improve efficiencies in the gas turbine system, the recirculated exhaust gas may also increase operational problems with the gas turbine system and power plant, in general. For example, exhaust gases recirculated directly from the HRSG can include a high moisture concentration or saturation level. Such an increased moisture concentration can increase a risk of moisture or condensate build-up within the compressor that over time can erode and / or corrode internal components of the compressor. Additionally, exhaust gases recirculated directly from the HRSG may include a concentration of impurities or contaminants, such as, for example, nitrogen oxides (NOx) or sulfur oxides (SOx). If exhaust gases recirculated into the compressor of the gas turbine system includes high levels of contaminants, the chemical compounds or contaminants can ‘“build-up” within the system overtime, causing erosion and / or mechanical failures, as well as an increase in(17851-1457) scheduled cleaning and / or maintenance of the gas turbine system. Accordingly, it would be desirable to implement an exhaust gas recirculation system for use with a combined cycle power plant that adjusts the characteristics of the exhaust gases before being recirculated to facilitate reducing or eliminating the risk of imparting undesirable conditions into the combined cycle power plant.BRIEF DESCRIPTION

[0004] A first aspect of the disclosure provides a system, including: a combined cycle power plant that includes a heat recovery steam generator (HRSG) in flow communication with a gas turbine system, and at least one computing device in communication with the combined cycle power plant. The HRSG generates an exhaust gas, and an exhaust gas recirculation assembly downstream from and in flow communication with the HRSG receives at least a portion of the exhaust gas. The exhaust gas recirculation assembly includes a direct contact cooler (DCC) in flow communication with and upstream from the gas turbine system. The at least one computing device is configured to control the combined cycle power plant by performing processes including: measuring a characteristic of the exhaust gas downstream from the exhaust gas recirculation assembly; and comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas, the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic. The at least one computing device is further configured to adjust operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

[0005] A second aspect of the disclosure provides a method for controlling a combined cycle power plant. The method includes measuring a characteristic of an exhaust gas downstream from an exhaust gas recirculation assembly of the combined cycle power plant. The exhaust gas recirculation assembly includes a direct contact cooler (DCC) in flow communication with a gas turbine system of the combined cycle power plant. The method also includes comparing the measured characteristic of the exhaust gas to one of a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range(17851-1457) for the exhaust gas. The predefined characteristic threshold and the predefined characteristic range are based on the measured characteristic of the exhaust gas. Additionally, the method can include adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

[0006] A third aspect of the disclosure provides a computer program product stored on a non-transitory computer-readable storage medium. When the computer program product is executed by at least one computing device, the program product controls a combined cycle power plant. The computer program product includes program code for measuring a characteristic of an exhaust gas downstream from an exhaust gas recirculation assembly of the combined cycle power plant. The exhaust gas recirculation assembly includes a direct contact cooler (DCC). The computer program product also includes program code for comparing the measured characteristic of the exhaust gas to one of a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas. The predefined characteristic threshold and the predefined characteristic range are based on the measured characteristic of the exhaust gas. Additionally, the computer program product includes program code for adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

[0007] The illustrative aspects of the present disclosure are designed to solve the problems herein described and / or other problems not discussed.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features of this disclosure will be more readily understood from the following detailed description of the various aspects of the disclosure taken in conjunction with the accompanying drawings that depict various embodiments of the disclosure, in which:

[0009] FIG. 1 is a schematic illustration of an exemplary combined cycle power plant including a gas turbine system, a steam turbine system, an exhaust gas recirculation(17851-1457)(EGR) assembly, and a computing device(s).

[0010] FIG. 2 is a schematic illustration of the exhaust gas recirculation (EGR) assembly including a portion of the combined cycle power plant of FIG. 1.

[0011] FIG. 3 is a flowchart illustrating an exemplary process for controlling a combined cycle power plant to recirculate exhaust gas from a heat recover steam generator (HRSG).

[0012] FIG. 4 is a schematic illustration of an exemplary environment including a control system for controlling the system of FIG. 1 including the combined cycle power plant, the exhaust gas recirculation assembly, and the computing device(s).

[0013] It is noted that the drawings of the disclosure are not to scale. The drawings are intended to depict only typical aspects of the disclosure, and therefore should not be considered as limiting the scope of the disclosure. In the drawings, like numbering represents like elements between the drawings.DETAILED DESCRIPTION

[0014] The embodiments described herein relate to exhaust gas recirculation assembly of a combined cycle power plant that processes and recirculates the exhaust gas back to a gas turbine system of the power plant. Typically, exhaust gases generated by heat recover stream generators are either exhausted from the power plant or are recirculated within the power plant as is (e.g., including contaminants, high moisture content / saturation levels, etc.). The systems described herein measure characteristics of the exhaust gases and adjust operational parameters of distinct portions of the power plant to alter undesirable characteristics, before recirculating the exhaust gases back to the gas turbine system. Adjusting operational characteristic(s) of the exhaust gases as such can facilitate improving the operational performance of the gas turbine system. Additionally, adjusting the characteristics of the exhaust gas before recirculation can facilitate reducing or eliminating a risk of imparting undesirable conditions (e.g., erosive contaminants) within the gas turbine system via the recirculated exhaust gas.

[0015] At least some benefits of the system including an exhaust gas recirculation assembly include: a) altered exhaust gases having fewer contaminants and other optimal characteristic(s) (e.g., temperature, pressure. pH level); b) improved operation of the gas turbine system of the power plant because of the altered exhaust gas recirculated therein;(17851-1457) and c) reduced or an eliminated risk of creating undesirable conditions within the gas turbine system by altering the exhaust gases before recirculation. Additional benefits realized by the system may include reducing an amount of potentially harmful exhaust gases being released into the ambient environment and / or reducing the demand of ambient air used by the compressor of the gas turbine system.

[0016] Unless otherwise indicated, approximating language, such as ‘'generally,” “substantially,” and “about,” as used herein indicates that the term so modified may apply to only an approximate degree, as would be recognized by one of ordinary7skill in the art, rather than to an absolute or perfect degree. Accordingly, a value modified by a term or terms such as “about,” “approximately,” and “substantially” is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Additionally, unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to, for example, a “second” item does not require or preclude the existence of, for example, a “first” or lower-numbered item or a “third” or higher-numbered item.

[0017] In addition, several descriptive terms may be used regularly herein, and it should prove helpful to define these terms at the onset of this section. These terms and their definitions, unless stated otherwise, are as follows. As used herein, "dow nstream" and “upstream” are terms that indicate a direction relative to the flow of a fluid, such as the working fluid through the turbine engine or, for example, the flow of air through the combustor or coolant through one of the turbine's component systems. The term "downstream" corresponds to the direction of flow of the fluid, and the term “upstream” refers to the direction opposite to the flow. The terms “forw ard” and “aft,” without any further specificity7, refer to directions, with “forward” referring to the front or compressor end of the engine, and “aft” referring to the rearward or turbine end of the engine. It is often required to describe parts that are at differing radial positions with regard to a center axis. The term “radial” refers to movement or position perpendicular to an axis. In cases such as this, if a first component resides closer to the axis than a second component, it will be stated herein that the first component is “radially inward” or “inboard” of the second component. If, on the other hand, the first component resides further from the axis than the(17851-1457) second component it may be stated herein that the first component is “radially outward” or “outboard” of the second component. The term “axial” refers to movement or position parallel to an axis. Finally, the term “circumferential” refers to movement or position around an axis. It will be appreciated that such terms may be applied in relation to the center axis of the turbine.

[0018] FIG. 1 shows a schematic depiction of an exemplary system 10 according to various embodiments of the disclosure. As shown, system 10 can include a combined cycle power plant 12 (hereafter, “power plant 12”) including a steam turbine (ST) system 18, which in the illustration shown, can include a high pressure (HP) portion 20, an intermediate pressure (IP) portion 22 and a low pressure (LP) portion 24. HP portion 20. IP portion 22 and LP portion 24 of ST system 18 are all coupled together, and / or positioned on, and / or rotate a shaft 26 to produce mechanical w ork and / or to drive an additional component of ST system 18. As shown in FIG. 1, shaft 26 of ST system 18 is coupled to and / or drives an external component, and more specifically, a generator 28 configured to generate power and / or produce a load.

[0019] Pow er plant 12 can further include a gas turbine (GT) system 30. In the exemplary embodiment, GT system 30 includes a compressor 32 that compresses an incoming flow of fluid 34 (e.g., air) as it flows therethrough. In a non-limiting example, fluid 34 includes ambient air surrounding GT system 30 / power plant 12 that is drawn directly into compressor 32. Additionally, and as discussed herein, fluid 34 can include a mixture of the ambient air surrounding GT system 30, and exhaust gases 36 provided directly to compressor 32 via an exhaust gas recirculation assembly (not shown in FIG. 1). Compressor 32 delivers a flow of compressed fluid 38 (e.g.. compressed fluid 34 / exhaust gases 36) to a combustor 40 that mixes the flow of compressed fluid 38 with a pressurized flow of fuel 42 provided by a fuel supply 44 and ignites the mixture to create a flow of combustion gases 46. The flow- of combustion gases 46 is in turn delivered to a turbine component 48, which typically includes a plurality of turbine blades (not shown). The flow of combustion gases 46 drives turbine component 48 to produce mechanical work. The mechanical w ork produced in turbine component 48 drives compressor 32 via a shaft 50 and is used to drive a generator 51 (e.g., external component) that generates power and / or produces a load. Rotating shaft 50 is supported by a rotor bearing 52 (hereafter, “bearing 52”) positioned within a bearing housing (not shown), adjacent turbine component 48.(17851-1457)Bearing 52 supports shaft 50 and enables the rotation of shaft 50 during operation of GT system 30, as discussed herein.

[0020] Although power plant 12 is shown in FIG. 1 to include a dual-shaft configuration, where two separate generators 28, 51 are utilized, it should be understood that in other non-limiting examples, ST system 18 and GT system 30 share a single shaft and in turn, share a single generator. Additionally, although power plant 12 is shown as only including a single ST system 18 and single GT system 30, it is understood that power plant 12 may include a plurality7of ST systems 18 and / or GT system(s) 30 that generate an operational load and / or power output.

[0021] Power plant 12 can also include a heat recovery steam generator (HRSG) 54 fluidly coupled and / or in flow communication with the ST system 18 (e.g., with HP portion 20, IP portion 22 and / or LP portion 24) and GT system 30. As shown in the non-limiting example of FIG. 1, HRSG 54 is coupled in flow communication with ST system 18 via exhaust conduit(s) 56 to receive exhaust fluid (e.g., steam) from ST system 18. as well as to provide steam to the portions of ST system 18 via supply conduits 58. Additionally in the non-limiting example, HRSG 54 is in flow communication with GT system 30 via an exhaust channel 60 coupled to and / or in fluid communication with turbine component 48. Exhaust channel 60 provides exhaust fluid (e.g.. gas) from GT system 30 to HRSG 54 to be utilized in generating and / or heating steam for ST system 18. A stack 61 of HRSG 54 exhausts or releases at least a portion of the exhaust gases 36 from HRSG 54 into the atmosphere and / or from power plant 12.

[0022] Power plant 12 can further include a carbon capture system 62 downstream from and in flow communication with HRSG 54. During operation of power plant 12, carbon capture system 62 produces a carbon dioxide stream from at least a portion of exhaust gases 36 expelled from HRSG 54. For example, at least a portion of exhaust gases 36 are exhausted or released from HRSG 54 and flow to carbon capture system 62. Carbon capture system 62 can process the portion of exhaust gases 36 to separate and / or to remove the carbon dioxide and / or to form a carbon dioxide stream. Gases free from carbon dioxide are released or expelled from carbon capture system 62 (e.g., into ambient), and the carbon dioxide stream is further processed (e.g., increased to supercritical pressure) for subsequent transportation and / or storage.(17851-1457)

[0023] In the exemplary embodiment shown in FIG. 1, power plant 12 also includes a blower-dampener component 64. In the exemplary' embodiment, blower-dampener component 64 is downstream from HRSG 54. More specifically, blower-dampener component 64 is downstream from and in flow- communication with HRSG 54 to receive at least a portion of the exhaust gases 36 exhausted and / or released from HRSG 54. As discussed herein, blower-dampener component 64 is also upstream from an exhaust gas recirculation assembly, and facilities channeling exhaust gases 36 from HRSG 54 to the exhaust gas recirculation assembly. Blower-dampener component 64 can be formed as any suitable component, or series of components, that facilitates the movement of the exhaust gases 36 within power plant 12, and that is capable of increasing and / or decreasing the pressure of the exhaust gases 36 and / or the flow' rate or velocity of the exhaust gases 36 as the gases 36 move through the pow er plant 12 (e.g., via exhaust gas recirculation assembly). As discussed herein, when exhaust gases 36 are recirculated back to compressor 32 of GT system 30, blower-dampener component 64 can adjust and / or alter (e.g., increase, decrease) the pressure and / or flow velocity of exhaust gases 36 within power plant 12 to facilitate improving / optimizing the operation of GT system 30 / power plant 12.

[0024] Pow er plant 12, in the exemplary embodiment, includes an exhaust gas recirculation (EGR) assembly 100 (hereafter, "EGR assembly 100”). EGR assembly 100 is downstream from and in flow communication with HRSG 54 and the blower-dampener component 64 of power plant 12 to facilitate receiving exhaust gases 36 from blow erdampener component 64. That is, blow er-dampener component 64 is upstream from EGR assembly 100 and downstream from HRSG 54, and blower-dampener component 64 is in flow communication with both HRSG 54 and EGR assembly 100. EGR assembly 100 is also upstream from and in flow communication with GT system 30. More specifically, and as shown in FIG. 1, EGR assembly 100 is in flow' communication with compressor 32to facilitate the recirculation and / or the supplying of exhaust gases 36 back to compressor 32 during operation of GT system 30 / power plant 12. as discussed herein. In the exemplary embodiment, EGR assembly 100 includes a direct contact cooler (DCC) 102 (hereafter, “DCC 102”). As discussed herein (see, FIG. 2), DCC 102 of EGR assembly 100 is in flow' communication with blower-dampener component 64 and compressor 32 of GT system 30. Additionally, as discussed herein, EGR assembly 100, and more specifically DCC 102, facilitates the adjusting, altering, and / or changing of measured characteristics of exhaust(17851-1457) gases 36 prior to recirculating exhaust gases 36 back to compressor 32. Altering the measured characteristics of exhaust gases 36 can facilitate improving / optimizing the operation of GT system 30 / power plant 12, and / or reducing / eliminating the risk of imparting undesirable conditions within GT system 30 / power plant 12, such as moisture and / or contaminants.

[0025] In the non-limiting example shown in FIG. 1, power plant 12 also includes a valve 104 downstream from EGR assembly 100. Specifically, valve 104 is downstream from EGR assembly 100 and upstream from compressor 32 of GT system 30. Valve 104 is also in flow communication with EGR assembly 100 (e.g., DCC 102) and compressor 32. During operation of power plant 12. valve 104 facilitates the recirculation exhaust gases 36 to compressor 32 of GT system 30. That is, and as discussed herein, valve 104, between EGR assembly 100 and compressor 32, controls whether exhaust gases 36 is supplied / recirculated to or closed-off from compressor 32, based on the measured characteristics of exhaust gases flowing through power plant 12.

[0026] As shown in FIG. 1, system 10 can include at least one computing device 108 configured to control power plant 12. Computing device(s) 108 can be hard-wired and / or wirelessly connected to and / or in communication with pow er plant 12, and distinct components of power plant 12 via any suitable electronic and / or mechanical communication component or technique. In the exemplary embodiment, computing device(s) 108 can be electrical coupled, operably coupled, and / or in electronic communication with blower-dampener 64 and valve 104. Computing device(s) 108, and its various components discussed herein, are a single stand-alone system that functions separate from another power plant control system (e.g., computing device)(not shown) that facilitates the control of pow er plant 12 and / or the adjustment of operational parameters for power plant 12 and its various components (e.g., blower-dampener 64, valve 104, and so on). Alternatively, computing device(s) 108 and its components can be integrally formed within, in communication with and / or formed as a part of a larger power plant control system (e.g., computing device) (not shown) that controls power plant 12 and / or adjusts operational parameters of pow er plant 12 and its various components, as discussed herein.

[0027] In various embodiments, computing device(s) 108 can include a control system 110 and a plurality of sensors 112 for controlling power plant 12 and / or adjusting operational parameters of power plant 12. As discussed herein, control system 110 can(17851-1457) control power plant 12 and / or adjust operational parameters of power plant 12. and of various components (e.g., blower-dampener 64, EGR assembly 100 / DCC 102, valve 104), to adjust, alter, and / or change measured characteristics of exhaust gases 36 prior to recirculating exhaust gases 36 back to compressor 32. Altering the measured characteristics of exhaust gases 36 can facilitate improving / optimizing the operation of GT system 30 / power plant 12, and / or reducing / eliminating the risk of imparting undesirable conditions within GT system 30 / power plant 12, such as moisture and / or contaminants.

[0028] As show n in FIG. 1, computing device(s) 108 includes and / or is electrical coupled, operably coupled, and / or in electronic communication with a plurality of sensors 112 positioned throughout, within, adjacent to and / or around system 10 to detect, determine, and / or measure characteristic(s) of exhaust gases 36 flowing through power plant 12, as discussed herein. Although a portion of the plurality of sensors 112 (e.g., sensor 112C upstream from blower-dampener component 64) are not depicted to be in communication with computing device(s) 108, it is understood that all sensors 112 of system 10 are in communication with and / or are capable of providing detected or measured data (e.g., characteristics) relating to exhaust gases 36 of pow er plant 12 to computing device(s) 108, as discussed herein. As shown in the non-limiting example of FIG. 1, a first sensor 112A of and / or connected to computing device(s) 108 is downstream from EGR assembly 100 / DCC 102 and upstream from GT system 30. Additionally, first sensor 112 is upstream from valve 104 of pow er plant 12. A second sensor 112B is upstream from EGR assembly 100 / DCC 102, and downstream from blow er-dampener component 64. In the exemplary embodiment, system 10 also includes a third sensor 112C upstream from blower-dampener component 64, and downstream from HRSG 54. A fourth sensor 112D is downstream from HRSG 54 and upstream from or positioned within stack 61 of HRSG 54. As discussed herein with respect to FIG. 2, system 10 and / or computing device(s) 108 includes a plurality of distinct sensors (e.g., sensors 112E - 112H) included within EGR assembly 100.

[0029] Sensor(s) 112 in communication with computing device(s) 108 of system 10 are formed as any suitable sensor or device configured to detect, determine, and / or measure data, information, and / or characteristics of exhaust gases 36 flowing through pow er plant 12 during operation. For example, sensors 112 positioned within power plant 12 may be any suitable sensor configured to detect, determine, and / or measure physical, thermal,(17851-1457) fluid-dynamic, and / or chemical characteristics of exhaust gases 36. The characteristic(s) of exhaust gases 36 measured by sensor(s) 112 include, but are not limited to, a temperature of exhaust gases 36, a pressure of exhaust gases 36, a flow rate or velocity of exhaust gases 36, a moisture content / saturation percentage of exhaust gases 36, an opacity of exhaust gases 36, a pH level of exhaust gases 36, a concentration of chemicals within exhaust gases 36 (e.g., oxygen (O2), carbon dioxide (CO2), etc.), a concentration of a contaminant or impurity within exhaust gases 36, and the like. In non-limiting examples where sensor(s) 112 is measuring a concentration of a contaminant or impurity within exhaust gases 36, sensor(s) 112 is capable of determining the concentration within a parts per million (ppm) or parts per billion (ppb) weight ratio. Contaminants or impurities included within exhaust gases 36 include any measurable chemical that can negatively impact or effect GT system 30 / compressor 32 (e.g., cause corrosion, erosion, and / or material deposition / build-up) if the exhaust gases 36 was flowed, supplied, and / or recirculated to compressor 32 during operation of power plant 12. For example, contaminants or impurities included within exhaust gases 36, and measured by sensor(s) 112, may include, but are not limited to only including, sodium (Na), nitrogen oxides (NOx), sulfur oxides (SOx), carbon dioxide (CO2), carbon monoxide (CO), or any other chemical that can negatively impact or effect GT system 30 / compressor 32, as discussed herein.

[0030] Each sensor 1 12A, 112B, 1 12C, 112D can measure each one of these characteristics of exhaust gases 36, or alternatively, each sensor 112A, 112B, 112C, 112D may be configured to only measure one or more predetermined characteristics of exhaust gases 36. For example, first sensor 112A can be configured to measure each characteristic of exhaust gases 36 (e.g., temperature, pressure, flow velocity, moisture, opacity. pH level, concentration of chemicals / contaminants, etc ), while second sensor 112B only measures the temperature, pressure, flow' velocity', and moisture content / saturation percentages. Additionally, third sensor 112C may also measure a predetermined number of characteristic(s) for exhaust gases 36. For example, third sensor 112C can be configured or capable of only measuring temperature, pressure, and flow velocity of exhaust gases 36. The characteristic measured by each sensor 112 can be predetermined based on the positioned or location of sensor within power plant 12. Additionally, the characteristic(s) measured by each sensor 112 can be dependent, at least in part, on the operational parameter to be adjusted in EGR assembly 100 / DCC 102 and / or power plant 12, as(17851-1457) discussed herein. For example, and as discussed herein, first sensor 112A and third sensor 1 12C can both be configured to measure the flow velocity of exhaust gases 36, and computing device(s) 108 operably coupled and / or in electronic communication with blower-dampener component 64 can adjust operational parameters of blower-dampener component 64.

[0031] Although four sensors 112A, 1 12B, 112C, 112D are illustrated, it is understood that in another non-limiting example, system 10 can include only one sensor 112, so long as sensor 112 is configured to provide computing device(s) 108, and specifically control system 110, with measured characteristics of exhaust gases 36, as discussed herein. The number of sensors 1 12 shown in FIG. 1 is exemplary and nonlimiting. As such, system 10 can include more or less sensors 112 than what is depicted in the Figures.

[0032] Sensors 112 provide computing device(s) 108, and specifically control system 110, with measured characteristics for exhaust gases 36 flowing through power plant 12, to determine if exhaust gases 36 can be recirculated back to GT system 30 during operation. That is, and as discussed herein, sensor(s) 112 of system 10 provides computing device(s) 108 and / or control system 110 with measured characteristics of exhaust gases 36, at least at a point downstream from EGR assembly 100 (e.g., sensor 112A). Additionally, and as discussed herein, computing device(s) 108 and / or control system 110 can compare the measured characteristics of exhaust gases 36 to predefined characteristic thresholds / predefined characteristic ranges for exhaust gases 36. Where the measured characteristic differ from the predefined characteristic thresholds / predefined characteristic ranges (e.g., exceed predefined characteristic thresholds, are outside of predefined characteristic ranges), computing device(s) 108 and / or control system 110 can adjust operational parameters for EGR assembly 100 (e.g., DCC 102) and / or distinct portions of power plant 12 (e.g., blower-dampener component 64, valve 104). Adjusting operational parameters of EGR assembly 100 and / or distinct portions of power plant 12 in turn can alter the measured characteristics of exhaust gases 36, which facilitates improving / optimizing the operation of GT system 30 / power plant 12, and / or reducing / eliminating the risk of imparting undesirable conditions within GT system 30 / power plant 12.(17851-1457)

[0033] Predefined characteristic thresholds for exhaust gases 36 define and / or represent upper limits of each measured characteristic of exhaust gases 36 that are acceptable and / or desired for operation of power plant 12. That is, the predefined characteristic thresholds define an upper limit of the measured characteristic of exhaust gases 36, such that exhaust gases 36 including measured characteristics at or below the predefined characteristic threshold can be recirculated to GT system 30. The recirculated exhaust gases 36, having a measured characteristic at or below the predefined characteristic threshold, facilitates improving / optimizing operational performance of GT system 30 and / or reducing / eliminating the risk of imparting undesirable conditions within GT system 30. For example, where exhaust gases 36 include a moisture content or saturation percentage below a predefined moisture content threshold, exhaust gases 36 can be recirculated to GT system 30 during operation. In this example, the risk of an undesirable level of moisture or saturation being present within GT system 30 / compressor 32 receiving exhaust gases 36 is facilitated to be reduced or eliminated. This in turn facilitates reducing or eliminating the risk to components of compressor 32 (e.g., stator vanes, rotor blades) of experiencing corrosion.

[0034] In another non-limiting example, the measured characteristic of exhaust gases 36 include a concentration of sulfur oxides (SOx) (e.g., contaminant). Additionally, the predefined characteristic threshold represents a maximum concentration of sulfur oxides (SOx) that can be present within exhaust gases 36, where exhaust gases can be recirculated to GT system 30. Where the measured concentration of sulfur oxides (SOx) in exhaust gases 36 is below the predefined concentration threshold for sulfur oxides (SOx), exhaust gases 36 can be recirculated to GT system 30 during operation. In the non-hmiting example, the risk of an undesirable concentration of sulfur oxides (Sox) being present within GT system 30 / compressor 32 via receiving exhaust gases 36 is facilitated to be reduced or eliminated. Recirculating exhaust gases 36 with a concentration of sulfur oxides (SOx) below the predefined concentration threshold facilitates reducing or eliminating the risk erosion and / or material deposition and / or build-up with GT system 30.

[0035] Predefined characteristic ranges for exhaust gases 36 define and / or represent an acceptable or desirable range for each measured characteristic of exhaust gases 36 to facilitate recirculation to GT system 30 during operation of power plant 12. That is, the predefined characteristic ranges define acceptable or desired ranges for the measured(17851-1457) characteristic of exhaust gases 36, such that exhaust gases 36 including measured characteristics within the predefined characteristic range can be recirculated to GT system 30. The recirculated exhaust gases 36, having a measured characteristic within the predefined characteristic range, facilitates improving / optimizing operational performance of GT system 30 and / or reducing / eliminating the risk of imparting undesirable conditions within GT system 30.

[0036] For example, where exhaust gases 36 includes a measured temperature within a predefined temperature range, exhaust gases 36 can be recirculated to GT system 30 during operation. In this example, exhaust gases that are flowed, supplied, and / or recirculated to GT system at the temperature within the predefined temperature range can facilitate improving / optimizing performance of GT system 30, and more specifically, the compression of exhaust gases 36 and fluid 34 within compressor 32. Additionally, recirculating exhaust gases 36 with a temperature within the predefined temperature range can ensure exhaust gases 36 have a temperature above a dew point temperature for exhaust gases 36, fluid 34, and / or the ambient environment surrounding compressor 32. Maintaining exhaust gases 36 at a temperature above the dew point temperature (e.g., within predefined temperature range) facilitates reducing / eliminating the risk of undesirable evaporative cooling taking place upstream from and / or within compressor 32 during operation of power plant 12.

[0037] In exemplary embodiments, predefined characteristic thresholds and / or predefined characteristic ranges are also based on, at least in part, additional aspects or factors relating to power plant 12 and / or the operation of power plant 12. For example, and continuing the example above, the predefined temperature range is dependent and / or based on, at least in part, the temperature of the ambient environment surrounding compressor 32 of GT system 30 and / or the temperature of fluid 34 mixing with exhaust gases 36 and drawn into compressor 32. In the example, the predefined temperature range defining an acceptable and / or desired temperature for exhaust gases 36 can change based upon an increase or decrease in temperature for the ambient environment surrounding compressor 32 and / or fluids 34. In another non-limiting example, the predefined a moisture content or saturation percentage threshold for exhaust gases 36 can be dependent and / or based on, at least in part, an amount of moisture contained in the ambient environment surrounding compressor 32 and / or fluids 34 flowing into compressor 32 during operation. Where(17851-1457) additional aspects are considered for defining the predefined characteristic thresholds and / or ranges, an additional sensor (not shown) positioned in the ambient environment, adjacent power plant 12, can detect, determine, and / or measure the applicable aspects. In another non-limiting example, computing device(s) 108 and / or control system 110 can obtain these additional aspects or factors from any other suitable source and / or system (e.g., weather reports).

[0038] As discussed herein, computing device(s) 108 and / or control system 110 of system 10 controls power plant 12, and more specifically, can adjust operational parameters of EGR assembly 100 and / or distinct portions of power plant 12. In an exemplary embodiment, computing device(s) 108, and more specifically control system 110, facilitates the measurement of a characteristic of exhaust gases 36 downstream from EGR assembly 100. The characteristic of exhaust gases 36 is measured by sensor 112A. As discussed herein, that characteristic can include a plurality of physical, thermal, fluiddynamic. and / or chemical characteristics of exhaust gases 36 (e.g., temperature, pressure, concentration of contaminants, etc.).

[0039] Once measured, the computing device(s) 108 / control system 110 compares the measured characteristics of exhaust gases 36 to a predefined characteristic threshold and / or a predefined characteristic range for exhaust gases 36. As discussed herein, the predefined characteristic threshold and predefined characteristic range is based on, at least in part, the measured characteristic, and additional aspects or factors relating to power plant 12 (e.g., ambient environment moisture / humidity). That is, the predefined characteristic threshold and predefined characteristic range corresponds to and / or includes similar measurement types (e.g.. temperature, pressure, concentration of contaminants, etc.) as the characteristic of exhaust gases 36 measured by sensor 1 12A.

[0040] Where computing device(s) 108, and more specifically control system 110, determines the measured characteristic of exhaust gases 36 exceeds the predefined characteristic threshold, or alternatively is outside the predefined characteristic range, operational parameters of power plant 12 are adjusted. That is, computing device(s) 108 / control system 110 can adjust operational parameters of EGR assembly 100 and / or distinct portions of power plant 12 when the measured characteristics of exhaust gases 36 differ from the predetermined characteristic threshold and / or the predetermined characteristic range. The adjusted operational parameters are specific to the EGR assembly(17851-1457)100 and / or distinct portions of power plant 12. Additionally, whether to adjust operational parameters of EGR assembly 100 or portions of power plant 12 is dependent on, at least in part, the measured characteristic that exceeds the predefined characteristic threshold, or is outside the predefined characteristic range. For example, where the measured characteristic includes the temperature of exhaust gases 36, operational parameters of EGR assembly 100 are adjusted to increase or decrease the temperature of exhaust gases 36 in DCC 102 to be within the predefined characteristic range, as discussed herein. In another non-limiting example where the measured characteristic includes a pressure or flow velocity of exhaust gases 36, operational parameters of power plant 12, and more specifically, blowerdampener component 64 are adjusted to increase or decrease the pressure / flow velocity of exhaust gases 36 in DCC 102 to be below the predefined characteristic threshold and / or within the predefined characteristic range. In an additional exemplary' embodiment, and as discussed herein with respect to FIG. 2, where the measured characteristic includes a concentration of contaminant(s) of exhaust gases 36, operational parameters of EGR assembly 100 / DCC 102 are adjusted to decrease the concentration of contaminants in exhaust gases 36 to be below the predefined characteristic threshold.

[0041] Although the non-limiting examples discussed herein describe only adjusting operational parameters of EGR assembly 100 or portions of power plant 12, it is understood that operational parameters of EGR assembly 100 and portions of power plant 12 can be adjusted simultaneously in response to the measured characteristic of exhaust gases 36 differing from the thresholds / ranges. For example, in addition to adjusting operational parameters of EGR assembly 100 / DCC 102 to adjust the temperature of exhaust gases 36. operational parameters of blower-dampener 64 can also be adjusted to aid in increasing or decreasing the temperature of exhaust gases 36. Additionally, it is understood that computing device(s) 108 / control system 110 can be operably coupled and / or in electronic communication with other portions of power plant 12 (e.g.. HRSG 54) to adjust operational parameters in response to the measured characteristic of exhaust gases 36 differing from the thresholds / ranges.

[0042] In an exemplary' embodiment, exhaust gases 36 can be recirculated, supplied, and / or flowed to GT system 30, even when the measured characteristic of exhaust gases 36 exceeds the predefined characteristic threshold, or alternatively is outside the predefined characteristic range. Exhaust gases 36 are recirculated while operational(17851-1457) parameters of EGR assembly 100 and / or portions of power plant 12 are adjusted. After operational parameters are adjusted, the measured characteristics of exhaust gases 36 recirculated back to GT system 30 will no longer exceed the predefined characteristic threshold and / or will be within the predefined threshold. For example, when the measured concentration of contaminants or impurities exceeds the predefined characteristic threshold, exhaust gases 36 can continue to be recirculated and / or flowed to GT system 30, as operational parameters of EGR assembly 100 are adjusted to lower the concentration of contaminants or impurities within exhaust gases 36. Overtime, and based on the adjusted operation parameters of EGR assembly 100. the concentration of contaminants or impurities measured within exhaust gases 36 may be reduced below the predefined characteristic threshold.

[0043] In another non-limiting example, exhaust gases 36 are prevented from flowing and / or recirculating to GT system 30. More specifically, exhaust gases 36 is not recirculated to compressor 32 of GT system 30 and / or EGR assembly 100 may temporarily become inactive (e g., no longer receive exhaust gases 36 from HRSG 54) in response to the measured characteristic exceeding the predefined characteristic threshold, or alternatively being outside the predefined characteristic range. In the non-limiting example where exhaust gases 36 is not supplied or recirculated to GT system 30, valve 104 may be completely closed to prevent the flow of exhaust gases 36 therethrough. Additionally, or alternatively, EGR assembly 100 may be temporarily deactivating and / or may temporarily prevent exhaust gases 36 from flowing through EGR assembly 100 for processing and / or recirculation. In exemplary embodiments, blower-dampener component 64 may be shut, closed, and / or inoperable to prevent exhaust gases 36 from flowing to EGR assembly 100. Rather, all exhaust gases 36 flow' from FIRSG 54 to carbon capture system 62. During the temporary' shut down and / or prevention of flowing exhaust gases 36 to GT system 30, operational parameters of EGR assembly 100 may be adjusted until the measured characteristics of exhaust gases 36 no longer exceed the predefined characteristic threshold and / or will be within the predefined threshold. For example, when the measured temperature of exhaust gases exceeds the predefined characteristic threshold, exhaust gases 36 is prevented from being recirculated and / or flowed to GT system 30 by adjusting valve 104 and / or EGR assembly 100. Operational parameters of EGR assembly 100 may subsequently be adjusted to ensure that the temperature of exhaust gases 36 is lowered(17851-1457) below the predefined characteristic threshold once exhaust gases 36 are flowed to GT system again and / or when EGR assembly 100 becomes operational again. Preventing exhaust gases 36 from flowing to GT system 30 can facilitate reducing / eliminating the risk of imparting undesirable conditions within GT system 30 / power plant 12, and / or facilitate preventing a reduction in operational performance by GT system 30, as discussed herein.

[0044] In additional exemplary embodiments, the amount of exhaust gases 36 flowing and / or recirculating to GT system 30 may be reduced. More specifically, exhaust gases 36 is not recirculated to compressor 32 of GT system 30 in response to the measured characteristic exceeding the predefined characteristic threshold, or alternatively being outside the predefined characteristic range. In the non-limiting example where the amount of exhaust gases 36 supplied or recirculated to GT system 30 is reduced, valve 104 may be adjusted and / or partially closed to reduce the amount of exhaust gases 36 flowed to GT system 30. Additionally, or alternatively, operational parameters of EGR assembly 100 may temporarily be adjusted to receive and / or intake less exhaust gases 36 from HRSG 54. In non-limiting examples, operational characteristics of blower-dampener component 64 may be adjusted (e.g., less blower power, partially closing dampener) to reduce the amount of exhaust gases 36 flowing to EGR assembly 100. During the temporary reduction in the amount of exhaust gases 36 flowed to GT system 30, operational parameters of EGR assembly 100 may be adjusted until the measured characteristics of exhaust gases 36 no longer exceed the predefined characteristic threshold and / or will be within the predefined threshold. In exemplar}' embodiments when the measured temperature of exhaust gases exceeds the predefined characteristic threshold, the amount of exhaust gases 36 recirculated and / or flowed to GT system 30 is reduced by adjusting valve 104 and / or operational parameters of EGR assembly 100. Operational parameters of EGR assembly 100 may subsequently be adjusted to ensure that the temperature of exhaust gases 36 is lowered below the predefined characteristic threshold before the amount of exhaust gases 36 flowed to GT system again is subsequently increased. Reducing the amount of exhaust gases 36 flowed to GT system 30 can facilitate reducing / eliminating the risk of imparting undesirable conditions within GT system 30 / power plant 12, and / or facilitate preventing a reduction in operational performance by GT system 30, as discussed herein.(17851-1457)

[0045] In response to the measured characteristic of exhaust gases 36 not exceeding the predefined characteristic threshold, or alternatively being within the predefined characteristic range, computing device(s) 108, and more specifically control system 110, determines exhaust gases 36 can be recirculated back to GT system 30. Exhaust gases 36 can be recirculated, supplied, and / or flowed from EGR assembly 100, through valve 104, and back to GT system 30 / compressor 32, as shown in FIG. 1. Additionally, where it is determined exhaust gases 36 can be recirculated back to GT system 30 based on the comparison, computing device(s) 108 / control system 110 also determines that the operational parameters of EGR assembly 100 and / or power plant 12 can remain the same. As discussed herein, recirculating exhaust gases 36 within power plant 12 can facilitate improving / optimizing the operation of GT system 30 / power plant 12, and / or reducing / eliminating the risk of imparting undesirable conditions within GT system 30 / power plant 12.

[0046] As discussed herein, one or more characteristics of exhaust gases 36 can be measured by sensors 112. As such, computing device(s) 108, and more specifically control system 110, can control power plant 12 based on multiple, measured characteristics of exhaust gases 36. For example, and while measuring a first characteristic of exhaust gases 36 (e.g., temperature) as discussed above, device(s) 108 / control system 110 can also measure a distinct characteristic of exhaust gases 36 (e.g., opacity). The characteristic can be measured downstream from EGR assembly 100 using sensor 112A, or upstream from EGR assembly 100 using sensor(s) 112B and / or 112C. Computing device(s) 108 / control system 110 can then compare the distinct, measured characteristic of exhaust gases 36 to a distinct, predefined characteristic threshold and / or a distinct, predefined charactenstic range. As similarly discussed herein, where the distinct, measured characteristic of exhaust gases 36 does not differ (e.g., exceed, outside) from the distinct, predefined characteristic threshold / range, no operational parameters of EGR assembly 100 and / or power plant 12 are adjusted. Conversely, operational parameters of EGR assembly 100 and / or portions of power plant 12 are adjusted in response to the distinct, measured characteristic of exhaust gases 36 differing from the distinct, predefined characteristic threshold / range. One or more operational parameter of a single component or portions (e.g., EGR assembly 100, blowerdampener component 64) of power plant 12 can be adjusted in view of the measured characteristic and the distinct, measured characteristic. Alternatively, or one or more(17851-1457) operational parameters of multiple components of power plant 12 can be adjusted based on the measured characteristic and the distinct, measured characteristic.

[0047] Additionally, and in support of controlling power plant 12 and adjusting operational parameters, computing device(s) 108 / control system 110 can also compare measured characteristics to determine if operational parameters should be adjusted. For example, computing device(s) 108, and more specifically control system 110, can measure a characteristic of exhaust gases 36 both downstream from EGR assembly 100 (e.g., sensor 112A) and upstream from EGR assembly 100 (e.g., sensor(s) 112B, 112C). Computing device device(s) 108 / control system 110 can then compare the downstream measured characteristic with the upstream measure characteristic. In response to the downstream measured characteristic being the same or substantially similar (e g., within a range) to the upstream measure characteristic, operational parameters of EGR assembly 100 and / or power plant 12 are maintained or unchanged. Conversely, the operational parameters of EGR assembly 100 / portions of power plant 12 are adjusted by computing device(s) 108 / control system 110 in response to the downstream measured characteristic differing from the upstream measure characteristic. Alternatively, operational parameters can be adjusted where the downstream measured characteristic are substantially similar to the upstream measure characteristic, and operational parameters can be maintained where the downstream measured characteristic differs from the upstream measure characteristic.

[0048] Continuing the example above, the pressure of exhaust gases 36 can be measured downstream from EGR assembly 100 using sensor 112A. The pressure of exhaust gases 36 can be within the predefined characteristic / temperature range for recirculating exhaust gases 36 to GT system 30 and / or maintaining operational parameters of EGR assembly 100 / DCC 102. However, the pressure is close to a lower limit of the predefined characteristic range. The pressure of exhaust gases 36 can also be measured upstream from EGR assembly 100 by sensor 112B, and subsequently compared to the downstream pressure measurement. In comparing the upstream and downstream pressures, computing device(s) 108, and more specifically control system 110, can determine whether the two measured pressures differ from one another, such as, for example, whether the upstream measured pressure is minimally greater than the downstream pressure. How ever, a minimal drop (e.g.. 1%) in pressure in the upstream measured pressure for the exhaust gases 36 will result in the downstream measured pressure of exhaust gases 36 being outside(17851-1457) of the predefined characteristic range. As such, computing device(s) 108 / control system 1 10 determines that operational parameters of blower-dampener component 64 should be adjusted to facilitate an increase in the pressure of exhaust gases 36 upstream from EGR assembly 100.

[0049] FIG. 2 shows a schematic view of EGR assembly 100 including DCC 102 and a portion of power plant 12. It is understood that similarly numbered and / or named components may function in a substantially similar fashion. Redundant explanation of these components has been omitted for clarity.

[0050] As shown in FIG. 2, DCC 102 of EGR assembly 100 is in flow communication with and downstream from blower-dampener component 64 for receiving exhaust gases 36 from HRSG 54 (see, FIG. 1). Additionally, DCC 102 is upstream from and in flow communication with compressor 32 of GT system 30 (see, FIG. 1), for recirculating exhaust gases 36 to compressor 32. In a non-limiting example, DCC 102 receives exhaust gases 36 from blower-dampener component 64 and subsequently cools and / or adjusts the temperature of exhaust gases 36 before flowing exhaust gases 36 to valve 104. DCC 102 cools and / or adjusts the temperature of exhaust gases 36 using heat exchanger 118. Heat exchanger 118 of EGR assembly 100 is in flow communication with DCC 102. Specifically, an inlet conduit 120 and an outlet conduit 122 fluidly couple and / or facilitate flow communication between DCC 102 and heat exchanger 118. During operation, heat exchanger 118 provides a working fluid 124 to DCC 102. Working fluid 124 provided to DCC 102 absorbs at least a portion of the heat from exhaust gases 36 and subsequently is flowed back to heat exchanger 118, where working fluid 124 is re-cooled in preparation for additional heat exchanges within DCC 102.

[0051] In anon-limiting example, EGR assembly 100 also includes a bypass valve 126 formed on a bypass conduit 128. Bypass conduit 128 extends between and facilitates flow communication between inlet conduit 120 and outlet conduit 122 of EGR assembly 100. In a non-limiting example where exhaust gases 36 does not require substantially cooling to be within the predefined characteristic range relating to temperature, bypass valve 126 allows at least a portion of working fluid 124 to bypass heat exchanger 118, before being flowed back to DCC 102. In the example, bypassed working fluid 124 can have a higher temperature than working fluid 124 flowed from heat exchanger 118. Working fluid 124 flowed from outlet conduit 122 to inlet conduit 120 via bypass conduit(17851-1457)128 can mix with working fluid 124 flowed directly from heat exchanger 118 to inlet conduit 120 and increase the overall temperature of working fluid 124 in inlet conduit 120 prior to it reaching DCC 102. This process can ensure exhaust gases 36 is not overcooled and / or the temperature is decreased such that exhaust gases 36 includes a temperature measured by sensor 112A that is below the predefined characteristic range, as discussed herein. As such, and as discussed herein, adjusting the operational parameters for EGR assembly 100 can include altering, adjusting, and / or changing a temperature of working fluid 124 provided to DCC 102 via heat exchanger 118 to cool, change, and / or decrease the temperature of exhaust gases 36 flowing through DCC 102.

[0052] In an exemplary embodiment, EGR assembly 100 utilizes a reagent 130 for adjusting measured characteristics of exhaust gases 36 flowing through EGR assembly 100. That is, EGR assembly 100 of power plant 12 can utilize reagent 130 to facilitate the removal of contaminants found within exhaust gases 36, the altering of the opacity of exhaust gases 36, and / or the changing of a pH level of exhaust gases 36 prior to exhaust gases 36 being recirculated to GT system 30. As shown in FIG. 2, reagent 130 can be introduced into heat exchanger 118 and combined with and / or flow to DCC 102 along with working fluid 124. Additionally, or alternatively, reagent 130 can be supplied directly to DCC 102 of EGR assembly 100 from a reagent reservoir (not shown). In either example, reagent 130 supplied to DCC 102 is combined with, mixed with, and / or is expelled from DCC 102 along with working fluid 124 of EGR assembly 100.

[0053] As discussed herein, reagent 130 facilitates the removal of contaminants found within exhaust gases 36, the altering of the opacity of exhaust gases 36, and / or the changing of a pH level of exhaust gases 36. As such, adjusting operational parameters of EGR assembly 100 can include exposing exhaust gases 36 to reagent 130 within DCC 102 of EGR assembly 100, and / or altering the amount and / or type of reagent 130 supplied to DCC 102 during operation of power plant 12. Reagent 130 can be formed from any suitable material or chemical composition that can remove contaminants from exhaust gases 36, alter the opacity of exhaust gases 36, and / or change the pH level of exhaust gases 36. For example, reagent 130 can be formed from any suitable chelating agent including sulfides and / or sulfites. Additionally, or alternatively, reagent 130 can include, but is not limited to, hydrogen peroxide, and / or plasma. Moreover, reagent 130 can include, but is not limited to, sodium hydroxide (NaOH), and / or ammonium hydroxide (NH4OH).(17851-1457)

[0054] To ensure exhaust gases 36 can be recirculated from EGR assembly 100 to GT system 30, EGR assembly 100 also includes additional sensors 1 12. For example, sensor 112E is downstream from DCC 102 and / or in flow communication with DCC 102 and heat exchanger 118. Sensor 112E also positioned within and / or in flow communication with outlet conduit 122. Sensor 112F is upstream from DCC 102 and downstream heat exchanger 118. Additionally, sensor 112F is positioned within and / or in flow communication within inlet conduit 120, and downstream from bypass conduit 128 within inlet conduit 120. Sensor 112G is positioned within and / or in flow' communication with a blowdown conduit 132. In the non-limiting example shown in FIG. 2, EGR assembly 100 include blowdown conduit 132 in flow' communication with outlet conduit 122, upstream from bypass conduit 128. Blowdown conduit 132 facilitates the removal of large particles, contaminants, and / or byproducts generated when exposing exhaust gases 36 to reagent(s) 130, as discussed herein. Sensor 112H is downstream from heat exchanger 118 and upstream from sensor 112F. Additionally as shown, sensor 112H is also upstream from bypass conduit 128.

[0055] Similar to sensors 112A-112D discussed herein with respect to FIG. 1, sensors 112E, 112F, 112G, 11214 of EGR assembly 100 also measure characteristics of working fluid 124 flowing through EGR assembly 100. For example, sensors 112E, 112F, 112G, 112H can measure a temperature of working fluid 124, a pressure of w orking fluid 124, a flow' rate or velocity of working fluid 124, a pH level of working fluid 124, a concentration of chemicals w ithin working fluid 124 (e.g., sodium (Na), silicon dioxide (SiCh)), and the like. Additionally, sensors 112E, 112F, 112G, 112H can measure other characteristics relating to working fluid 124 including, but not limited to. a conductivity of w orking fluid 124, and / or a total suspended solid (TSS) within working fluid 124.

[0056] Each sensor 112E, 112F, 112G, 112H of EGR assembly 100 can measure each one of these characteristics of working fluid 124, or alternatively, each sensor 112E, 112F, 112G, 112H may only measure one or more predetermined characteristics of w orking fluid 124. For example, sensor 112E can measure each characteristic of working fluid 124 (e.g., temperature, pressure, flow' velocity, conductivity, pH level, concentration of chemicals / contaminants, etc.), while sensor 112 only measures temperature, pressure, and flow velocity of working fluid 124. Additionally, sensor 112G can also measure a predetermined number of characteristic(s) for exhaust gases 36. For example, sensor 112G(17851-1457) of EGR assembly 100 can be configured to or capable of only measuring temperature, pressure, flow velocity, conductivity, pH levels, and the TSS of working fluid 124. The characteristic measured by each sensor 112E-112H can be predetermined based on the positioned or location of sensor within EGR assembly 100. Additionally, the characteristic(s) measured by each sensor 112E-112H of EGR assembly 100 can be dependent, at least in part, on the operational parameter to be adjusted in EGR assembly 100 / DCC 102, as discussed herein.

[0057] Although four sensors 112E, 112F, 112G, 112H are illustrated, it is understood that in another non-limiting example, EGR assembly 100 can include only one sensor 112. so long as sensor 112 is configured to provide computing device(s) 108, and specifically control system 110, with measured characteristics of working fluid 124, as discussed herein. The number of sensors 112 shown in FIG. 2 is exemplary and nonlimiting. As such, EGR assembly 100 can include more or less sensors 112 than what is depicted in the Figures. Additionally, although not shown in FIG. 2, it is understood that each sensor 112E-112H of EGR assembly 100 is operably coupled and / or in electronic communication with computing device(s) 108, as similarly discussed and shown herein with respect to sensors 112A-112D in FIG. 1.

[0058] As similarly discussed herein, computing device(s) 108, and more specifically control system 110, can analyze the measured characteristics of working fluid 124 and adjust operational parameters of EGR assembly 100 to facilitate the recirculation of exhaust gases 36 to GT system 30. For example, and as discussed herein, sensor 112E and / or sensor 112G measure the pH level of working fluid 124 flowing through outlet conduit 122 / blowdown conduit 132. respectively. Additionally, computing device(s) 108 / control system 110 knows a pH level of exhaust gases 36 provided to DCC 102 (e.g., via sensor 112B), and can determine or calculate a pH level of working fluid 124 flowed from heat exchanger 118 and / or flowing through inlet conduit 120. Utilizing and / or comparing the measured characteristics / pH levels for exhaust gases 36 and working fluid 124, computing device(s) 108, and more specifically control system 110, can determine that the pH level of exhaust gases 36 is not within the predefined characteristic range. This in turn facilitates computing device(s) 108 / control system 110 determining that that operational parameters for EGR assembly 100 should be adjusted. In the example, device(s) 108 / control system 1 10 can adjust the amount of reagent 130 being supplied to(17851-1457)DCC 102 during operation to ensure exhaust gases 36 exits DCC 102 within a desired pH level and / or a pH level that is within the predefined characteristic range, as discussed herein.

[0059] FIG. 3 illustrates an exemplary process for controlling a combined cycle power plant system. Specifically, FIG. 3 is a flowchart depicting an exemplary process for controlling a power plant system to facilitate the recirculation of exhaust gases from a heat recover steam generator (HRSG) back to a compressor of a gas turbine system of the power plant. In some cases, the processes can be performed using system 10, power plant 12, and EGR assembly 100, as discussed above with respect to FIGs. 1 and 2.

[0060] In process Pl, at least one characteristic of the exhaust gases is measured. More specifically, at least one characteristic(s) of the exhaust gases expelled from a heat recovery steam generator (HRSG) of a combined cycle power plant is measured, detected, and / or determined. The characteristic(s) is measured downstream from an exhaust gas recirculation (EGR) assembly of the power plant. The EGR assembly includes a direct contact cooler (DCC) downstream from the HRSG, wherein the DCC is in flow communication with the HRSG and the gas turbine system of the combined cycle power plant. The measured characteristic(s) include, but are not limited to only including, a temperature of the exhaust gases, a pressure of the exhaust gases, a flow velocity of the exhaust gases, a moisture content of the exhaust gases, an opacity of the exhaust gases, a pH level of the exhaust gases, and / or a concentration of a contaminant of the exhaust gases. In non-limiting examples, one characteristic of the exhaust gases can be measured downstream from the EGR assembly, or alternatively, a plurality of distinct characteristics can be measured downstream from the EGR assembly.

[0061] In process P2, show n in phantom as optional, the characteristic(s) of the exhaust gases is measured upstream from the EGR assembly of the power plant. More specifically, the same characteristic(s) of the exhaust gases measured in process Pl, are also measured upstream from the EGR assembly and downstream from the HRSG providing the exhaust gases. In non-limiting examples, one characteristic of the exhaust gases can be measured upstream from the EGR assembly, or alternatively, a plurality' of distinct characteristics can be measured upstream from the EGR assembly.(17851-1457)

[0062] In process P3, shown in phantom as optional, the characteristic(s) of the exhaust gases measured downstream from the EGR assembly are compared to the characteristic(s) of the exhaust gases measured upstream from the EGR assembly. More specifically, the downstream measurement and the upstream measurement of the characteristic(s) of the exhaust gases are compared to determine if the downstream, measured characteristic(s) differs from the upstream, measured characteristic(s). In a nonlimiting example where the downstream measured characteristic(s) differs from the upstream measure characteristic (e.g., “YES” at process P3), the process of controlling the power plant continues at process P6. Alternatively in the non-limiting example, where the downstream measured characteristic(s) is the same or substantially similar (e.g., within a range) to the upstream measure character! stic(s) (e.g., “NO” at process P3), the process of controlling the pow er plant continues to process P4. In another non-limiting example, the process of controlling the power plant continues at process P6 when the downstream measured characteristic(s) is substantially similar to the upstream measure character! stic(s). Additionally in the non-limiting example, the process of controlling the power plant continues at process P4 when the downstream measured characteristic(s) differ from the upstream measure characteristic(s).

[0063] As shown and discussed herein, processes P2 and P3 are illustrated as optional. In the exemplary embodiment where process P2 is not performed, process P3 is also not performed. As such, the processes for controlling the power plant as shown in FIG. 3 starts at process Pl and proceeds immediately to process P4.

[0064] In process P4, the measured characteristic(s) of the exhaust gases are compared to predefined characteristic(s) thresholds for the exhaust gases and / or predefined characteristic(s) ranges for the exhaust gases. The predefined characteristic(s) thresholds and the predefined characteristic(s) ranges are based on, at least in part, the measured characteristic(s) (e.g., process Pl). Additionally, the predefined characteristic(s) thresholds and the predefined characteristic(s) ranges are based on, at least in part, additional aspects or factors relating to the pow er plant and / or the operation of power plant (e.g., ambient environment). Where a plurality of characteristics are measured in process Pl, each characteristic can be compared to a corresponding predefined characteristic threshold and / or predefined characteristic range. In a non-limiting example where the measured characteristic(s) differs (e.g., exceeds threshold, outside of range) from the predefined(17851-1457) characteristic(s) threshold / range (e.g., "YES ’ at process P4), the process of controlling the power plant continues at process P6. Alternatively in the non-limiting example, where the measured characteristic(s) is the same or substantially similar (e.g., equal to / less than threshold, within range) to the predefined characteristic(s) threshold / range (e.g., “NO” at process P4), the process of controlling the power plant continues to process P5.

[0065] In process P5, the exhaust gases are recirculated to the gas turbine system of the power plant. More specifically, and as a result of determining that the measured characteristic(s) is the same or substantially similar to the predefined characteristic(s) threshold / range (e.g.. “NO” at process P4), the exhaust gases are recirculated from the EGR assembly to the compressor of the gas turbine system, to be reused within the power plant. Recirculating the exhaust gases from the EGR assembly to the gas turbine system can facilitate improving / optimizing the operation of the gas turbine system 30 and / or the power plant 12. Additionally, ensuring that the exhaust gases include measured characteristic(s) that do not exceed predefined characteristic(s) thresholds and / or are within the predefined characteristic(s) range (e.g., “NO” at process P4) before recirculation facilitates reducing / eliminating the risk of imparting undesirable conditions (e.g., contaminants, moisture) within the gas system and / or the power plant.

[0066] In process P6, operational parameters of the power plant are adjusted. More specifically, and in response to determining that the exhaust gases include measured characteristic(s) that exceed predefined characteristic(s) thresholds and / or are outside of the predefined characteristic(s) range (e.g., “YES” at process P4), operational parameters for the EGR assembly and / or distinct portions of the power plant are adjusted, altered, and / or changed. Adjust the operational parameters of the EGR assembly / distinct portions of the power plant aid in altering the measured characteristic(s) of the exhaust gas, such that subsequent to the adjustment of the operational parameters, the measured characteristic(s) of the exhaust gases become the same or substantially similar to the predefined characteristic(s) threshold / range (e.g., “NO” at process P4). This in turn facilitates the recirculation of the exhaust gases from the EGR assembly to the gas turbine system, as discussed herein.

[0067] The adjusting of the operational parameters and / or the portion of the power plant (e.g., the EGR assembly, etc.) that requires adjusted operational parameters is dependent, at least in part, on the measured characteristic(s) of the exhaust gas. For(17851-1457) example, where the measured characteristic includes a temperature of the exhaust gas, adjusting the operational parameter can include altering a temperature of a working fluid provided to the DCC of the EGR assembly to change (e.g., cool) the temperature of the exhaust gas. In the example, the temperature of the working fluid can be changed or altered using a heat exchanger of the EGR assembly that is in flow communication with the DCC. In another non-limiting example, where the measured characteristic includes a pressure and / or a flow velocity of the exhaust gas, adjusting the operational parameter can include adjusting operational parameters of a blower-dampener component of the power plant to increase or decrease the pressure and / or flow velocity of the exhaust gases as it flows to the EGR assembly. In the non-limiting example, the blower-dampener component is upstream from the EGR assembly of the power plant, and downstream from the HRSG. In an additional non-limiting example, where the measured characteristic includes a concentration of a contaminant and / or a pH level of the exhaust gas, adjusting the operational parameter can include exposing the exhaust gases to a reagent within the DCC and / or adjusting the amount of reagent supplied to the DCC during operation. Exposing the exhaust gases to the reagent or reagents can reduce the concentration of the contaminants including in the exhaust gases and / or can alter the pH level of the exhaust gas.

[0068] In some embodiments, and in response to determining that the exhaust gases include measured characteristic(s) that exceed predefined characteristic(s) thresholds and / or are outside of the predefined characteristic(s) range (e.g., “YES” at process P4), the exhaust gases may still be recirculated to the gas turbine system (e.g., process P5). That is, subsequent to or during the adjusting of the operational parameters of the EGR assembly and / or components of the combined cycle power plant in process P6. exhaust gases may still be recirculated to gas turbine system. For example, where a concentration of a contaminant or impurity exceeds a predefined characteristic threshold, the exhaust gases may still be recirculated to the gas turbine system. Operational parameters of the EGR assembly and / or components of the combined cycle power plant may also be adjusted to reduce the concentration of the contaminant or impurity in the exhaust gases. In other nonlimiting examples, additional processes (e.g., processes P7 and P8) may be performed to prevent and / or reduce the amount of exhaust gases being recirculated, as discussed herein.(17851-1457)

[0069] In process P7, shown in phantom as optional, the exhaust gases are prevented from being flowed to the gas turbine system of the power plant. More specifically, and after determining that the measured characteristic(s) differs from the predefined characteristic(s) threshold / range (e g., ‘‘YES” at process P4) and operational parameters of the EGR assembly and / or components of the combined cycle power plant are adjusted (e.g., process P6), the exhaust gases are prevented from and / or not supplied to the gas turbine system. In exemplar}' embodiments, the exhaust gas may be prevented from flowing to the gas turbine system by closing a supply valve of the EGR assembly upstream of the gas turbine system, and / or temporarily deactivating EGR assembly within the combined cycle power plant. Preventing exhaust gases that includes measured characteristic(s) that exceed predefined characteristic(s) thresholds and / or are outside of the predefined characteristic(s) range (e.g., “YES” at process P4) from flowing to the gas turbine system facilitates reducing / eliminating the risk of imparting undesirable conditions (e.g., contaminants, moisture) within the gas system and / or the power plant. In process P8. shown in phantom as optional, the amount of exhaust gases being flowed to the gas turbine system of the power plant is reduced. More specifically, and after determining that the measured characteristic(s) differs from the predefined characteristic(s) threshold / range (e.g., “YES” at process P4) and operational parameters of the EGR assembly and / or components of the power plant are adjusted (e.g., process P6), the amount of exhaust gases flowed and / or supplied to the gas turbine system is reduced. In exemplar}' embodiments, the amount of exhaust gas flowing to the gas turbine system may be reduced by adjusting a supply valve of the EGR assembly upstream of the gas turbine system, and / or temporarily adjusting operational parameters of the EGR assembly to reduce the amount exhaust gas drawn into the EGR assembly. Reducing the amount of exhaust gases flowing to the gas turbine system facilitates reducing / eliminating the risk of imparting undesirable conditions (e.g., contaminants, moisture) within the gas system and / or the power plant.

[0070] FIG. 4 shows an illustrative environment 140. To this extent, environment 140 includes computer infrastructure 142 that can perform the various process steps described herein for controlling combined cycle power plant 12. In particular, computer infrastructure 142 is shown including a computing device 108 that includes control system 110, which enables computing device 108 to control power plant 12 by performing one or more of the process steps of the disclosure.(17851-1457)

[0071] Computing device 108 is shown including a storage component 144, a processing component 146, an input / output (I / O) component 148, and a bus 150. Further, computing device 108 is shown in communication with power plant 12 and / or sensors 112. In general, processing component 146 executes computer program code, such as control system 110, that is stored in storage component 144 or an external storage component (not shown). While executing computer program code, processing component 146 can read and / or write data, such as control system 110, to / from storage component 144 and / or I / O component 148. Bus 150 provides a communications link between each of the components in computing device 108. I / O component 148 can comprise any device that enables a user 152 to interact with computing device 108 or any device that enables computing device 108 to communicate with one or more other computing devices. Input / output devices (including but not limited to keyboards, displays, pointing devices, etc.) can be coupled to the system either directly or through intervening 1 / 0 component 148.

[0072] Computing device 108 can include any general -purpose computing article of manufacture capable of executing computer program code installed by a user 152 (e.g., a personal computer, server, handheld device, etc.). However, it is understood that computing device 108 and control system 110 are only representative of various possible equivalent computing devices that performs the various process steps of the disclosure. To this extent, in other embodiments, computing device 108 can include any specific purpose computing article of manufacture comprising hardw are and / or computer program code for performing specific functions, any computing article of manufacture that comprises a combination of specific purpose and general-purpose hardware / software, or the like. In each case, the program code and hardware can be created using standard programming and engineering techniques, respectively.

[0073] Similarly, computer infrastructure 142 is only illustrative of various types of computer infrastructures for implementing the disclosure. For example, in one embodiment, computer infrastructure 142 comprises two or more computing devices (e.g., a server cluster) that communicate over any type of wired and / or wireless communications link, such as a network, a shared memory, or the like, to perform the various process steps of the disclosure. When the communications link comprises a netw ork, the network can comprise any combination of one or more types of networks (e.g., the Internet, a wide area network, a local area network, a virtual private network, etc.). Netw ork adapters is also(17851-1457) coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Modems, cable modem and Ethernet cards are just a few of the currently available types of network adapters. Regardless, communications between the computing devices utilizes any combination of various types of transmission techniques.

[0074] As previously discussed herein, control system 1 10 enables computing infrastructure 142 to control power plant 12 and recirculate exhaust gases 36 (see, FIG. 1) within power plant 12. To this extent, control system 110 is shown including exhaust gas characteristic(s) data 154, predefined characteristic(s) threshold / range data 156, exhaust gas recirculation assembly operational parameter(s) data 158. and combined cycle power plant operational parameter(s) data 160. Operation of each of these data is discussed further herein, for example, with respect to processes P1-P8 as shown in FIG. 3. However, it is understood that some of the various data shown in FIG. 4 can be implemented independently, combined, and / or stored in memory for one or more separate computing devices that are included in computer infrastructure 142. Further, it is understood that some of the data and / or functionality may not be implemented, or additional data and / or functionality can be included as part of environment 140.

[0075] The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flowchart illustration, and combinations of blocks in the block diagrams and / or flow chart illustration, can be implemented by special purpose hardw arebased systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.(17851-1457)

[0076] As discussed herein, various systems and components are described as “obtaining’’ data (e.g., obtaining characterise c(s) of exhaust gases 36, etc ). It is understood that the corresponding data can be obtained using any solution. For example, the corresponding system / component can generate and / or be used to generate the data, retrieve the data from one or more data stores (e.g., a database), receive the data from another system / component, and / or the like. When the data is not generated by the particular system / component, it is understood that another system / component can be implemented apart from the system / component shown, which generates the data and provides it to the system / component and / or stores the data for access by the system / component.

[0077] As will be appreciated, the present disclosure can be embodied as a system, method or computer program product. Accordingly, the present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmw are, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, the present disclosure can take the form of a computer program product embodied in any tangible medium of expression having computer-usable program code embodied in the medium.

[0078] Any combination of one or more computer usable or computer readable medium(s) is utilized. The computer-usable or computer-readable medium can be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory ), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a transmission media such as those supporting the Internet or an intranet, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of this document, a computer-usable or computer-readable medium(17851-1457) can be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-usable medium includes a propagated data signal with the computer- usable program code embodied therewith, either in baseband or as part of a carrier wave. The computer usable program code is transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc. Computer program code for carrying out operations of the present disclosure is written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code is executed entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer is connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection is made to an external computer (for example, through the Internet using an Internet Service Provider).

[0079] The present disclosure is described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus / systems and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions are provided to a processor of a general- purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0080] These computer program instructions are also stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instruction means which implement the function / act specified in the flowchart and / or block diagram block or blocks.(17851-1457)

[0081] The computer program instructions are also loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

[0082] At least one technical effect is to provide a combined cycle power plant that includes an exhaust gas recirculation assembly that measures characteristic(s) of the exhaust gases and adjusts operational parameters of the power plant before recirculating the exhaust gases back to a gas turbine of the power plant.

[0083] The foregoing drawings show some of the processing associated according to several embodiments of this disclosure. In this regard, each drawing or block within a flow diagram of the drawings represents a process associated with embodiments of the method described. It should also be noted that in some alternative implementations, the acts noted in the drawings or blocks can occur out of the order noted in the figure or, for example, may in fact be executed substantially concurrently or in the reverse order, depending upon the act involved. Also, one of ordinary skill in the art will recognize that additional blocks that describe the processing can be added.

[0084] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0085] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately” and “substantially,”(17851-1457) are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and / or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. “Approximately” and / or “substantially” as applied to a particular value of a range applies to both values, and unless otherwise dependent on the precision of the instrument measuring the value, may indicate + / - 10% of the stated value(s).

[0086] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiment was chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

[0087] Exemplary systems, methods, and computer program products that use an exhaust gas(es) recirculation assembly within a combined cycle power plant for recirculating exhaust gas within the power plant are described herein. Moreover, the systems, methods, and computer program products described herein facilitate improving / optimizing operations of the power plant, and / or reducing / eliminating the risk of imparting undesirable conditions (e.g., impurities, moisture) within the power plant. The exemplary systems, methods, and program products as described herein provide several advantages over conventional designs and processes, including increasing the operational efficiency and performance of a gas turbine system of the power plant by recirculating exhaust gas, while simultaneously reducing or eliminating the risk of introducing undesirable conditions back into the gas turbine system with the recirculated exhaust gas. For example, the above-described systems, methods, and program products facilitate adjusting operational parameters of portions of the power plant system (e.g., exhaust gas(17851-1457) recirculation assembly, blower-dampener components) to ensure the exhaust gas is recirculated back to the compressor of the gas turbine system at an optimum temperature, pressure, and / or flow velocity. This in turn increases the efficiency and performance of the gas turbine system when compared to conventional designs that only utilize ambient air in the compressor. Moreover, the above-described systems, methods, and program products facilitate adjusting operational parameters of portions of the power plant system (e.g., exhaust gas recirculation assembly, blower-dampener components) to alter characteristic(s) of the exhaust gases including concentrations of chemi cals / contaminants included therein, moisture concentration / saturation levels, pH levels, and the like, before recirculating the exhaust gases back to the gas turbine system. Similar to the temperature / pressure / flow velocity, adjusting characteristics such as the moisture concentration can also increase the efficiency and performance of the gas turbine system. Additionally, altering characteristics of the exhaust gas, like removing contaminants and changing the pH level, can reduce or eliminate the risk of imparting undesirable conditions within the gas turbine system. These undesirable conditions can reduce operation of the gas turbine system and degrade or negatively affect the gas turbine system over its operational life.

[0088] The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Modifications, which fall within the scope of the present invention, will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims. The systems described herein are not limited to the specific embodiments described herein, but rather portions of the various systems may be utilized independently and separately from other systems described herein.

[0089] Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. Moreover, references to “one embodiment” in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. In accordance with the principles of the invention, any feature of a drawing may be referenced and / or claimed in combination with any feature of any other drawing.(17851-1457)

[0090] Further aspects of the invention are provided by the subject matter of the following clauses: A system, comprising a combined cycle power plant including: a heat recovery steam generator (HRSG) in flow communication with a gas turbine system, the HRSG configured to generate an exhaust gas; and an exhaust gas recirculation assembly downstream from and in flow communication with the HRSG for receiving at least a portion of the exhaust gas, the exhaust gas recirculation assembly including a direct contact cooler (DCC) in flow communication with and upstream from the gas turbine system; and at least one computing device in communication with the combined cycle power plant, the at least one computing device configured to control the combined cycle power plant by performing at least one process: measuring a characteristic of the exhaust gas downstream from the exhaust gas recirculation assembly; comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas, the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

[0091] The system in accordance with any of the preceding clauses, wherein the processes performed by the at least one computing device to control the combined cycle power plant further includes: one of preventing the exhaust gas from flowing to the gas turbine system or reducing an amount of the exhaust gas flowing to the gas turbine system in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range; and recirculating the exhaust gas from the exhaust gas recirculation assembly to the gas turbine system in response to the measured characteristic of the exhaust gas: not exceeding the predefined characteristic threshold, or being within the predefined characteristic range.

[0092] The system in accordance with any of the preceding clauses, wherein the at least one characteristic of the exhaust gas includes at least one of: a temperature of the exhaust gas, a pressure of the exhaust gas, a flow velocity of the exhaust gas, a moisture content of the exhaust gas, an opacity of the exhaust gas, a pH level of the exhaust gas. and a concentration of a contaminant of the exhaust gas.(17851-1457)

[0093] The system in accordance with any of the preceding clauses, wherein the combined cycle power plant further includes a blower-dampener component upstream from the exhaust gas recirculation assembly, and wherein the at least one computing device is configured to adjust the operational parameters of the distinct portion of the combined cycle power plant by performing processes including: adjusting operational parameters of the blower-dampener component to increase or decrease at least one of the pressure of the exhaust gas or the flow velocity of the exhaust gas.

[0094] The system in accordance with any of the preceding clauses, wherein the at least one computing device is configured to adjust the operational parameters of the exhaust gas recirculation assembly by performing processes including: exposing the exhaust gas to a reagent within the DCC to reduce the concentration of the contaminant of the exhaust gas.

[0095] The system in accordance with any of the preceding clauses, wherein the exhaust gas recirculation assembly further includes a heat exchanger in flow communication with the DCC, and wherein the at least one computing device is configured to adjust the operational parameters of the exhaust gas recirculation assembly by performing processes including: altering a temperature of a working fluid provided to the DCC via the heat exchanger to change the temperature of the exhaust gas.

[0096] The system in accordance with any of the preceding clauses, further comprising a first sensor downstream from the DCC and upstream from the gas turbine system, the first sensor operably coupled to the at least one computing device; and a second sensor upstream from the DCC of the exhaust gas recirculation assembly, the second sensor operably coupled to the at least one computing device.

[0097] The system in accordance with any of the preceding clauses, further comprising a third sensor positioned upstream from the second sensor, the third sensor operably coupled to the at least one computing device.

[0098] The system in accordance with any of the preceding clauses, wherein the processes performed by the at least one computing device to control the combined cycle power plant further includes: measuring a distinct characteristic of the exhaust gas one of downstream or upstream from the exhaust gas recirculation assembly; comparing the distinct, measured characteristic of the exhaust gas to one of: a distinct, predefined characteristic threshold for the exhaust gas, or a distinct, predefined characteristic range for(17851-1457) the exhaust gas, the distinct, predefined characteristic threshold and the distinct, predefined characteristic range based on the distinct, measured characteristic; and adjusting distinct, operational parameters of at least one of the exhaust gas recirculation assembly, or the combined cycle power plant in response to the distinct, measured characteristic of the exhaust gas: exceeding the distinct, predefined characteristic threshold, or being outside of the distinct, predefined characteristic range.

[0099] The system in accordance with any of the preceding clauses, wherein the processes performed by the at least one computing device to control the combined cycle power plant further includes: measuring the characteristic of the exhaust gas upstream from the exhaust gas recirculation assembly; comparing the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly to the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly; and adjusting the operational parameters of at least one of the exhaust gas recirculation assembly, or the combined cycle power plant in response to the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly differing from the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly.

[0100] A method for controlling a combined cycle power plant, the method comprising measuring a characteristic of an exhaust gas downstream from an exhaust gas recirculation assembly of the combined cycle power plant, the exhaust gas recirculation assembly including a direct contact cooler (DCC) in flow communication with a gas turbine system of the combined cycle power plant; comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas. or a predefined characteristic range for the exhaust gas, the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

[0101] The method in accordance with any of the preceding clauses, further comprising one of preventing the exhaust gas from flowing to the gas turbine system or reducing an amount of the exhaust gas flowing to the gas turbine system in response to the(17851-1457) measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range; and recirculating the exhaust gas from the exhaust gas recirculation assembly to the gas turbine system in response to the measured characteristic of the exhaust gas: not exceeding the predefined characteristic threshold, or being within the predefined characteristic range.

[0102] The method in accordance with any of the preceding clauses, wherein the at least one characteristic of the exhaust gas includes at least one of: a temperature of the exhaust gas, a pressure of the exhaust gas, a flow velocity of the exhaust gas, a moisture content of the exhaust gas, an opacity of the exhaust gas, a pH level of the exhaust gas. and a concentration of a contaminant of the exhaust gas.

[0103] The method in accordance with any of the preceding clauses, wherein the adjusting of the operational parameters of the distinct portion of the combined cycle power plant further includes: adjusting operational parameters of a blower-dampener component of the combined cycle power plant to increase or decrease at least one of the pressure of the exhaust gas or the flow velocity of the exhaust gas, the blower-dampener component upstream from the exhaust gas recirculation assembly.

[0104] The method in accordance with any of the preceding clauses, wherein the adjusting of the operational parameters of the exhaust gas recirculation assembly of the combined cycle power plant further includes: exposing the exhaust gas to a reagent within the DCC to reduce the concentration of the contaminant of the exhaust gas.

[0105] The method in accordance with any of the preceding clauses, wherein the adjusting of the operational parameters of the exhaust gas recirculation assembly of the combined cycle power plant further includes: altering a temperature of a working fluid provided to the DCC via a heat exchanger to change the temperature of the exhaust gas, the heat exchanger in flow communication with the DCC.

[0106] The method in accordance with any of the preceding clauses, further comprising measuring a distinct characteristic of the exhaust gas one of downstream or upstream from the exhaust gas recirculation assembly; comparing the distinct, measured characteristic of the exhaust gas to one of: a distinct, predefined characteristic threshold for the exhaust gas, or a distinct, predefined characteristic range for the exhaust gas, the distinct, predefined characteristic threshold and the distinct, predefined characteristic range based on the distinct, measured characteristic; and adjusting distinct, operational(17851-1457) parameters of at least one of the exhaust gas recirculation assembly, or the distinct portion of the combined cycle power plant in response to the distinct, measured characteristic of the exhaust gas: exceeding the distinct, predefined characteristic threshold, or being outside of the distinct, predefined characteristic range.

[0107] The method in accordance with any of the preceding clauses, further comprising measuring the characteristic of the exhaust gas upstream from the exhaust gas recirculation assembly; comparing the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly to the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly; and adjusting the operational parameters of at least one of the exhaust gas recirculation assembly, or the portion of the combined cycle power plant in response to the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly differing from the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly.

[0108] A computer program product stored on a non-transitory computer-readable storage medium, which when executed by at least one computing device, controls a combined cycle power plant, the computer program product comprising program code for measuring a characteristic of an exhaust gas downstream from an exhaust gas recirculation assembly of the combined cycle power plant, the exhaust gas recirculation assembly including a direct contact cooler (DCC); comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas, the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

[0109] The computer program product in accordance with any of the preceding clauses, wherein the program code causes the at least one computing device to control the combined cycle power plant by performing processes including: measuring a distinct characteristic of the exhaust gas one of downstream or upstream from the exhaust gas recirculation assembly; comparing the distinct, measured characteristic of the exhaust gas700674-WO-l(17851-1457) to one of: a distinct, predefined characteristic threshold for the exhaust gas. or a distinct, predefined characteristic range for the exhaust gas, the distinct, predefined characteristic threshold and the distinct, predefined characteristic range based on the distinct, measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or the distinct portion of the combined cycle power plant in response to the distinct, measured characteristic of the exhaust gas: exceeding the distinct, predefined characteristic threshold, or being outside of the distinct, predefined characteristic range.

Claims

(17851-1457)CLAIMSWhat is claimed is:

1. A system, comprising: a combined cycle power plant including: a heat recovery steam generator (HRSG) in flow communication with a gas turbine system, the HRSG configured to generate an exhaust gas; and an exhaust gas recirculation assembly downstream from and in flow communication with the HRSG for receiving at least a portion of the exhaust gas, the exhaust gas recirculation assembly including a direct contact cooler (DCC) in flow communication with and upstream from the gas turbine system; and at least one computing device in communication with the combined cycle power plant, the at least one computing device configured to control the combined cycle power plant by performing at least one process : measuring a characteristic of the exhaust gas downstream from the exhaust gas recirculation assembly; comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas, the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

2. The system of claim 1, w herein the processes performed by the at least one computing device to control the combined cycle powder plant further includes: one of preventing the exhaust gas from flowing to the gas turbine system or reducing an amount of the exhaust gas flowing to the gas turbine system in response to the measured characteristic of the exhaust gas:(17851-1457) exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range; and recirculating the exhaust gas from the exhaust gas recirculation assembly to the gas turbine system in response to the measured characteristic of the exhaust gas: not exceeding the predefined characteristic threshold, or being within the predefined characteristic range.

3. The system of claim 1, wherein the at least one characteristic of the exhaust gas includes at least one of: a temperature of the exhaust gas. a pressure of the exhaust gas, a flow velocity of the exhaust gas, a moisture content of the exhaust gas, an opacity of the exhaust gas, a pH level of the exhaust gas, and a concentration of a contaminant of the exhaust gas.

4. The system of claim 3, wherein the combined cycle power plant further includes a blower-dampener component upstream from the exhaust gas recirculation assembly, and wherein the at least one computing device is configured to adjust the operational parameters of the distinct portion of the combined cycle power plant by performing processes including: adjusting operational parameters of the blower-dampener component to increase or decrease at least one of the pressure of the exhaust gas or the flow velocity of the exhaust gas.

5. The system of claim 3, wherein the at least one computing device is configured to adjust the operational parameters of the exhaust gas recirculation assembly by performing processes including: exposing the exhaust gas to a reagent within the DCC to reduce the concentration of the contaminant of the exhaust gas.(17851-1457)6. The system of claim 3. wherein the exhaust gas recirculation assembly further includes a heat exchanger in flow communication with the DCC, and wherein the at least one computing device is configured to adjust the operational parameters of the exhaust gas recirculation assembly by performing processes including: altering a temperature of a working fluid provided to the DCC via the heat exchanger to change the temperature of the exhaust gas.

7. The system of claim 1, further comprising: a first sensor downstream from the DCC and upstream from the gas turbine system, the first sensor operably coupled to the at least one computing device; and a second sensor upstream from the DCC of the exhaust gas recirculation assembly, the second sensor operably coupled to the at least one computing device.

8. The system of claim 7. further comprising: a third sensor positioned upstream from the second sensor, the third sensor operably coupled to the at least one computing device.

9. The system of claim 1, wherein the processes performed by the at least one computing device to control the combined cycle power plant further includes: measuring a distinct characteristic of the exhaust gas one of downstream or upstream from the exhaust gas recirculation assembly; comparing the distinct, measured characteristic of the exhaust gas to one of: a distinct, predefined characteristic threshold for the exhaust gas, or a distinct, predefined characteristic range for the exhaust gas, the distinct, predefined characteristic threshold and the distinct, predefined characteristic range based on the distinct, measured characteristic; and adjusting distinct, operational parameters of at least one of the exhaust gas recirculation assembly, or the combined cycle power plant in response to the distinct, measured characteristic of the exhaust gas: exceeding the distinct, predefined characteristic threshold, or being outside of the distinct, predefined characteristic range.(17851-1457)10. The system of claim 1. wherein the processes performed by the at least one computing device to control the combined cycle power plant further includes: measuring the characteristic of the exhaust gas upstream from the exhaust gas recirculation assembly; comparing the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly to the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly; and adjusting the operational parameters of at least one of the exhaust gas recirculation assembly, or the combined cycle power plant in response to the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly differing from the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly.

11. A method for controlling a combined cycle power plant, the method comprising: measuring a characteristic of an exhaust gas downstream from an exhaust gas recirculation assembly of the combined cycle power plant, the exhaust gas recirculation assembly including a direct contact cooler (DCC) in flow communication with a gas turbine system of the combined cycle power plant; comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas, the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

12. The method of claim 11, further comprising: one of preventing the exhaust gas from flowing to the gas turbine system or reducing an amount of the exhaust gas flowing to the gas turbine systemin response to the(17851-1457) measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range; and recirculating the exhaust gas from the exhaust gas recirculation assembly to the gas turbine system in response to the measured characteristic of the exhaust gas: not exceeding the predefined characteristic threshold, or being within the predefined characteristic range.

13. The method of claim 11, wherein the at least one characteristic of the exhaust gas includes at least one of: a temperature of the exhaust gas, a pressure of the exhaust gas, a flow velocity of the exhaust gas, a moisture content of the exhaust gas, an opacity of the exhaust gas, a pH level of the exhaust gas, and a concentration of a contaminant of the exhaust gas.

14. The method of claim 13, wherein the adjusting of the operational parameters of the distinct portion of the combined cycle power plant further includes: adjusting operational parameters of a blower-dampener component of the combined cycle power plant to increase or decrease at least one of the pressure of the exhaust gas or the flow velocity of the exhaust gas. the blower-dampener component upstream from the exhaust gas recirculation assembly.

15. The method of claim 13, wherein the adjusting of the operational parameters of the exhaust gas recirculation assembly of the combined cycle power plant further includes: exposing the exhaust gas to a reagent within the DCC to reduce the concentration of the contaminant of the exhaust gas.(17851-1457)16. The method of claim 13, wherein the adjusting of the operational parameters of the exhaust gas recirculation assembly of the combined cycle power plant further includes: altering a temperature of a working fluid provided to the DCC via a heat exchanger to change the temperature of the exhaust gas, the heat exchanger in flow communication with the DCC.

17. The method of claim 11, further comprising: measuring a distinct characteristic of the exhaust gas one of dow nstream or upstream from the exhaust gas recirculation assembly; comparing the distinct, measured characteristic of the exhaust gas to one of: a distinct, predefined characteristic threshold for the exhaust gas, or a distinct, predefined characteristic range for the exhaust gas, the distinct, predefined characteristic threshold and the distinct, predefined characteristic range based on the distinct, measured characteristic; and adjusting distinct, operational parameters of at least one of the exhaust gas recirculation assembly, or the distinct portion of the combined cycle power plant in response to the distinct, measured characteristic of the exhaust gas: exceeding the distinct, predefined characteristic threshold, or being outside of the distinct, predefined characteristic range.

18. The method of claim 11 , further comprising: measuring the characteristic of the exhaust gas upstream from the exhaust gas recirculation assembly; comparing the characteristic of the exhaust gas measured dow nstream from the exhaust gas recirculation assembly to the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly; and adjusting the operational parameters of at least one of the exhaust gas recirculation assembly, or the portion of the combined cycle power plant in response to the characteristic of the exhaust gas measured downstream from the exhaust gas recirculation assembly differing from the characteristic of the exhaust gas measured upstream from the exhaust gas recirculation assembly.(17851-1457)19. A computer program product stored on a non-transitory computer-readable storage medium, which when executed by at least one computing device, controls a combined cycle power plant, the computer program product comprising program code for: measuring a characteristic of an exhaust gas downstream from an exhaust gas recirculation assembly of the combined cycle power plant, the exhaust gas recirculation assembly including a direct contact cooler (DCC); comparing the measured characteristic of the exhaust gas to one of: a predefined characteristic threshold for the exhaust gas, or a predefined characteristic range for the exhaust gas. the predefined characteristic threshold and the predefined characteristic range based on the measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or a distinct portion of the combined cycle power plant in response to the measured characteristic of the exhaust gas: exceeding the predefined characteristic threshold, or being outside of the predefined characteristic range.

20. The computer program product of claim 19, wherein the program code causes the at least one computing device to control the combined cycle power plant by performing processes including: measuring a distinct characteristic of the exhaust gas one of dow nstream or upstream from the exhaust gas recirculation assembly; comparing the distinct, measured characteristic of the exhaust gas to one of: a distinct, predefined characteristic threshold for the exhaust gas, or a distinct, predefined characteristic range for the exhaust gas, the distinct, predefined characteristic threshold and the distinct, predefined characteristic range based on the distinct, measured characteristic; and adjusting operational parameters of at least one of the exhaust gas recirculation assembly, or the distinct portion of the combined cycle power plant in response to the distinct, measured characteristic of the exhaust gas: exceeding the distinct, predefined characteristic threshold, or being outside of the distinct, predefined characteristic range.

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