Direct contact coolers (DCC) for combined cycle power plants and methods for treating exhaust gases

Abstract

A direct contact cooler (DCC) includes a housing including an inlet section in flow communication with a heat recovery steam generator (HRSG). The inlet section is oriented to receive exhaust gases generated in the HRSG. The DCC also includes at least one sprayer array within the housing, adjacent to, and downstream from, the inlet section. The at least one sprayer array is configured to spray a cooling fluid within the housing. Additionally, the DCC also includes at least one packed bed within the housing and adjacent to the at least one sprayer array, and a wet electrostatic precipitator (WESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

Description

(17851-1506)DIRECT CONTACT COOLERS (DCC) FOR COMBINED CYCLE POWER PLANTS AND METHODS FOR TREATING EXHAUST GASESTECHNICAL FIELD

[0001] The disclosure relates generally to combined cycle power plants, and more particularly, to direct contact coolers (DCC) used in combined cycle power plants, and methods for treating exhaust gases using the DCCs.BACKGROUND

[0002] Combined cycle power plants typically include a heat recovery steam generator (HRSG) coupled in communication with a gas turbine system. The HRSG recovers or receives waste heat from exhaust gases produced by the gas turbine system, converts a portion of the waste heat to steam, and subsequently channels 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 to 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 gases may also increase operational problems with the gas turbine system and power plant. 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 include 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 creating an increased scheduled cleaning and / or(17851-1506) maintenance of the gas turbine system.

[0004] Furthermore, conventional exhaust gas recirculation assemblies include multiple, distinct components for treating the exhaust gases prior to recirculation. For example, a conventional recirculation assembly can include a cooler apparatus for cooling the exhaust gases, and a distinct contaminant removal apparatus downstream from the cooler apparatus. Because these apparatuses are distinct, each apparatus requires an amount of physical space, i.e., a footprint, within the power plant system. Additionally, each apparatus must be fluidly coupled to enable the exhaust gases to be shared or routed between the apparatuses during the treatment process. Often, the conduits coupling these apparatuses are long and / or include multiple turns or bends. As a result, the flow rate of the exhaust gases can undesirably decrease as it flow s between the various apparatuses of conventional gas recirculation assemblies.

[0005] Accordingly, it would be desirable to implement an exhaust gas recirculation system for use with a combined cycle power plant that can treat the exhaust gases before recirculation, maintain a desired flow rate without the need for additional components, and that has a reduced footprint within the powder plant.BRIEF DESCRIPTION

[0006] A first aspect of the disclosure provides a direct contact cooler (DCC), including a housing including an inlet section in flow communication with a heat recovery steam generator (HRSG). The inlet section is oriented to receive exhaust gases generated in the HRSG. The DCC also includes at least one sprayer array within the housing, adjacent to. and downstream from, the inlet section. The at least one sprayer array is configured to spray a cooling fluid within the housing. Additionally, the DCC also includes at least one packed bed within the housing and adjacent to the at least one sprayer array, and a wet electrostatic precipitator (WESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

[0007] A second aspect of the disclosure provides a combined cycle power plant, including a heat recover}' steam generator (HRSG) in flow' communication with a gas turbine system. The HRSG is configured to generate exhaust gases. The combined cycle power plant also includes an exhaust gas recirculation (EGR) assembly downstream from and in flow communication with the HRSG for receiving at least a portion of the exhaust gases. The(17851-1506)EGR assembly includes a direct contact cooler (DCC) in flow communication with and upstream from the gas turbine system. The DCC includes a housing including an inlet section in flow communication with the HRSG. The inlet section oriented to receive at least the portion of the exhaust gases generated in the HRSG. The DCC also includes at least one sprayer array within the housing, adjacent to, and downstream from, the inlet section. The at least one sprayer array is configured to spray a cooling fluid within the housing. Additionally, the DCC also includes at least one packed bed within the housing and adjacent to the at least one sprayer array, and a wet electrostatic precipitator (WESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

[0008] A third aspect of the disclosure provides a method for treating exhaust gases generated by a heat recovery’ steam generator (HRSG). The method includes channeling exhaust gases generated by the HRSG through a housing of a direct contact cooler (DCC) and cooling the exhaust gases within the housing using a cooling fluid provided by at least one sprayer array within the housing of the DCC. The method also includes removing a contaminant entrained within the exhaust gases using the cooling fluid provided by the at least one sprayer array within the housing of the DCC. Additionally, the method includes removing at least one of a distinct contaminant or moisture from the exhaust gases using a wet electrostatic precipitator (WESP) within the housing of the DCC. The WESP being downstream from the at least one sprayer array of the DCC.

[0009] 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

[0010] 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:

[0011] 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 (EGR) assembly, and a computing device(s).

[0012] FIG. 2 is a schematic illustration of the exhaust gas recirculation (EGR) assembly(17851-1506) including a portion of the combined cycle power plant of FIG. 1.

[0013] FIG. 3 is a schematic illustration of another embodiment of the exhaust gas recirculation (EGR) assembly including a portion of the combined cycle power plant of FIG. 1.

[0014] FIG. 4 is a schematic illustration of an additional embodiment of the exhaust gas recirculation (EGR) assembly including a portion of the combined cycle power plant of FIG. 1.

[0015] FIG. 5 is a flowchart illustrating an exemplary process for treating exhaust gas generated by a heat recovery steam generator (HRSG).

[0016] 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

[0017] The embodiments described herein relate to exhaust gas recirculation assembly of a combined cycle power plant that processes and recirculates exhaust gases 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 devices and systems described herein include the necessary components for treating the exhaust gases in preparation for recirculation in a single direct contact cooler (DCC) housing. Combining or including all requirement components necessary to treat the exhaust gases prior to recirculation improves the flow rate of the exhaust gases, as the gases are not required to move through various conduits, including multiple turns, to be treated by distinct systems, as is common in conventional designs. Additionally, combining all components in a single housing facilitates significantly reducing the overall size of the exhaust gas recirculation assembly responsible for treating the exhaust gases before recirculating the gases back to the gas turbine system of the power plant.

[0018] At least some benefits of the system including an exhaust gas recirculation assembly include: a) providing altered exhaust gases that have fewer contaminants and other optimal characteristic(s) (e.g., temperature, pressure, pH level); b) improved(17851-1506) operation of the gas turbine system of the power plant as a result of using the altered exhaust gas recirculated therein; c) reduced or an eliminated risk of creating undesirable conditions within the gas turbine system by altering the exhaust gases before recirculation; d) more easily maintaining a desired flow rate for the exhaust gases while being treated within the exhaust gas recirculation assembly; and (e) reducing the overall space or footprint required for the exhaust gas recirculation system by including all exhaust gases treatment components within a single housing. 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.

[0019] 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 ordinary skill 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.

[0020] 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 “forward” and “aft,” without any further specificity, 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(17851-1506) 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 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.

[0021] FIG. 1 is a schematic illustration of an exemplary an exemplary system 10. 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 work and / or to drive an additional component of ST system 18. Moreover, and 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.

[0022] Power plant 12 can also 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 w'ith a pressurized flow7of 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, w'hich typically includes a plurality of turbine blades (not shown). The flow(17851-1506) of combustion gases 46 drives turbine component 48 to produce mechanical work. The mechanical work 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. Bearing 52 supports shaft 50 and enables the rotation of shaft 50 during operation of GT system 30, as discussed herein.

[0023] 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 nonlimiting 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 plurality of ST systems 18 and / or GT system(s) 30 that generate an operational load and / or power output.

[0024] 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 nonlimiting 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.

[0025] 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(17851-1506) 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.

[0026] 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 via a conduit 66. 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 power 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, via recirculation conduit 68, 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. Although discussed herein as a combination of a blower and a dampener, it is understood that blower dampener component 64 can also be formed as only a blower component, or alternatively, only a dampener component.

[0027] Power 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, and receives exhaust gases 36 from blower-dampener component 64. That is, blower-dampener component 64 is upstream from EGR assembly 100 and downstream from HRSG 54, and blow er-dampener component 64 is in flow communication with both HRSG 54 and EGR assembly 100 via conduit 66. 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(17851-1506) compressor 32 via recirculation conduit 68 to facilitate the recirculation and / or the return of treated 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 treatment (e.g., adjusting, altering, and / or changing of characteristics) of exhaust gases 36 prior to recirculating exhaust gases 36 back to compressor 32 via recirculation conduit 68. Treating exhaust gases 36 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, such as moisture and / or contaminants.

[0028] As shown in FIG. 1, system 10 can include at least one computing device 104 programmed to control power plant 12. Computing device(s) 104 can be hard-wired and / or wirelessly connected to and / or in communication with power plant 12, and distinct components of pow er plant 12 via any suitable electronic and / or mechanical communication component or technique. In the exemplary' embodiment, computing device(s) 104 can be electrically coupled, operably coupled, and / or in electronic communication with blower-dampener 64. Computing device(s) 104, and its various components discussed herein, are a single stand-alone system that functions separately from another pow er plant control system (e.g.. computing device) (not shoyvn) that facilitates the control of power plant 12 and / or the adjustment of operational parameters for power plant 12 and its various components (e.g., blower-dampener 64, etc.). Alternatively, computing device(s) 104 and its components can be integrally-formed within, in communication w ith, 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 power plant 12 and its various components, as discussed herein.

[0029] In various embodiments, computing device(s) 104 can include a control system 106 and at least one sensor 108 for controlling power plant 12 and / or adjusting operational parameters of power plant 12. As discussed herein, control system 106 can control pow er 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, etc.), when treating exhaust(17851-1506) gases 36 prior to recirculating exhaust gases 36 back to compressor 32. As shown in FIG. 1 , computing device(s) 104 includes and / or is electrical coupled, operably coupled, and / or in electronic communication with at least one sensor 108 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. It is understood that all sensors 108 included in system 10 are in communication with and / or are capable of providing detected or measured data or characteristics relating to exhaust gases 36 of power plant 12 to computing device(s) 104, as discussed herein.

[0030] As shown in the non-limiting example of FIG. 1, a sensor 108A of and / or connected to computing device(s) 104 is upstream from EGR assembly 100 / DCC 102, and downstream from blower-dampener component 64. Additionally, a distinct sensor 108B (shown in phantom as optional) is included within recirculation conduit 68, downstream from EGR assembly 100 / DCC 102 and upstream from GT system 30. It is to be understood that system 10 can include a plurality of sensors 108 positioned in various portions of power plant 12 and / or EGR 10 for measuring or detecting data or characteristics relating to exhaust gas 36.

[0031] Sensor(s) 108 in communication with computing device(s) 104 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 power plant 12 during operation. For example, sensors 108 positioned within power plant 12 may be any suitable sensor configured to detect, determine, and / or measure physical, thermal, fluid-dynamic, and / or chemical characteristics of exhaust gases 36. The characteristic(s) of exhaust gases 36 measured by sensor(s) 108 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, a pH level of exhaust gases 36, a concentration of chemicals or contaminants / impurities within exhaust gases 36 (e.g., oxygen (O2), carbon dioxide (CO2), etc.), and the like. In non-limiting examples where sensor(s) 108 measures a concentration of a contaminant or impurity within exhaust gases 36, sensor(s) 108 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(17851-1506) deposition / build-up) if the exhaust gases 36 were 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) 108, 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 could negatively impact or effect GT system 30 / compressor 32, as discussed herein.

[0032] Sensors 108 provide computing device(s) 104, and specifically control system 106, with measured characteristics for exhaust gases 36 flowing through power plant 12, to determine if operational parameters of components of power plant 12 and / or EGR assembly 100 require adjustment. For example, where sensor 108A measures and determines if the flow rate or velocity of the exhaust gases 36 is below a predetermined, desired flow rate, control system 106 can adjust operational parameters of blowerdampener 64 to increase the flow rate of exhaust gases 36 prior to being provided to EGR assembly 100. Additionally, or alternatively, where sensor 108B measures and determines if the temperature of the exhaust gases 36 flowing through recirculation conduit 68 is above a desired temperature, control system 106 can adjust operational parameters of DCC 102 to decrease the temperature of exhaust gases 36 being treated within DCC 102.

[0033] FIG. 2 illustrates 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.

[0034] 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 via conduit 66 (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 via recirculation conduit 68. In a non-limiting example, and as discussed herein, DCC 102 receives exhaust gases 36 from conduit 66 and subsequently treats exhaust gases 36 before routing exhaust gases 36 to recirculation conduit 68.

[0035] DCC 102 includes a single housing 110 that includes a plurality of sections and / or components oriented to treat exhaust gases 36. For example, in the exemplary embodiment, housing 110 of DCC 102 includes an inlet section 1 12 in flow communication with HRSG(17851-1506)54 of power plant 12. More specifically, inlet section 112 is in flow communication and / or fluidly coupled to blower-dampener component 64, via conduit 66, and receives exhaust gases 36 generated in HRSG 54 and channeled to DCC 102 via conduit 66. As shown in FIG. 2, exhaust gases 36 enter DCC 102 via inlet section 112 and flow in a direction (D) based on. at least in part, thermal properties of exhaust gases 36, flow rate and / or velocity of exhaust gases 36, and / or the configuration of inlet section 112 of housing 110 for DCC 102.

[0036] DCC 102 also includes at least one sprayer array 118 within housing 110. As shown in the non-limiting example of FIG. 2, two sprayer arrays 118A, 118B are within housing 110, adjacent to and downstream from, inlet section 1 12. More specifically, a first sprayer array 118A is directly adjacent to, and immediately downstream from, inlet section 112 of housing 110. Additionally, a second sprayer array 118B is also positioned within housing 110 and is downstream from first sprayer array 118 A. As discussed herein, sprayer array (s) 118 are oriented to spray a cooling fluid 120 within housing 110 to facilitate reducing a temperature of the exhaust gases 36 and / or to facilitate removing chemicals, contaminants, and / or impurities entrained within exhaust gases 36. Sprayer array (s) 118 are oriented in any suitable spray configuration or using any known mist device that is capable of supplying cooling fluid 120 within housing 110 of DCC 102 to treat exhaust gases 36, as described herein. Additionally, and as discussed herein the cooling fluid 120 is any suitable fluid (e.g., water) that facilitates cooling and / or reducing the temperature of exhaust gases 36 flowing through housing 110 of DCC 102. For example, cooling fluid 120 includes denim and / or pure-water with non-alkaline, and with the combination of pH reagent(s) prevents and / or substantially reduces the risk of adding trace amounts of elements and / or impurities in exhaust gases 36 during processing, as discussed herein.

[0037] In the non-limiting example, DCC 102 also includes at least one packed bed 122 within housing 110. In the exemplary embodiment, packed bed 122 is within housing 110, adjacent to sprayer array(s) 118, and downstream from inlet section 112. As shown in FIG. 2, packed bed 122 is between first spray array 118A and second spray array 118B, and / or downstream from first spray array 118A and upstream from second spray array 118B. Packed bed 122 may be any suitable filtration device or assembly and can be formed from any suitable material that aids in treating exhaust gases 36. That is, and as discussed herein, packed bed 122 of DCC 102 can facilitate cooling or reducing the temperature of exhaust(17851-1506) gases 36 flowing therethrough. In non-limiting examples, packed bed 122 can include a packing material (not shown) including, but not limited to, polymer materials (e g., polypropylene), metals, ceramics, and / or any combination thereof.

[0038] In the exemplary embodiment, each of the spray arrays 118A, 118B may represent and / or define a distinct zone for DCC 102. More specifically, first spray array 118A may define an “adiabatic cooling zone” where exhaust gases 36 are cooled to a predetermined temperature. For example, first spray array 118A may facilitate cooling exhaust gases 36 to its wet bulb temperature (WBT). Additionally, second spray array 118B may represent and / or define a “packed bed zone.” Second spray array 118B, in conjunction with packed bed 122, may facilitate the heat transfer with exhaust gases 36, such that exhaust gases 36 exits DCC 102 at the desired and / or predetermined to be recirculated within EGR assembly 100, as discussed herein.

[0039] Additionally, DCC 102 includes a wet electrostatic precipitator (WESP) 124 within housing 110. In the exemplary embodiment. WESP 124 is downstream from sprayer array(s) 118 and / or packed bed 122. As shown, WESP 124 is downstream from second sprayer array 118B. Additionally as shown in FIG. 2, WESP 124 is spaced a distance from and / or is separated from second sprayer array 118B within housing 110 such that a maintenance access area 126 (shown in phantom) is formed or defined therebetween. Maintenance access area 126 provides an operator of DCC 102 with access to WESP 124 from wi thin housing 110. That is, a door or access ingress (not shown) can be defined in housing 110 of DCC 102 that is sized to enable an operator to enter and / or access maintenance access area 126, and in turn be provided access to WESP 124 to perform, for example, maintenance, inspection, and the like on WESP 124, as well as additional components of DCC 102 (e g., sprayer array(s) 118, packed bed 122, etc.). WESP 124 is formed as any suitable filterless device or system that facilitates removing and / or reducing aerosol, mist, moisture, CMAS (calcium-magnesium-alumino-silicate), and / or other fine particles or particulates within exhaust gases 36 flowing through DCC 102 using electrostatic charges, as described herein. In other non-limiting examples, WESP 124 is formed as a two-stage electrostatic precipitator.

[0040] DCC 102 can also include a mist eliminator 128 downstream from WESP 124. In the exemplary embodiment, mist eliminator 128 is within housing 110 of DCC 102, directly adjacent to, and downstream from, WESP 124. In other non-limiting examples(17851-1506)(see, FIG. 4). mist eliminator 128 is adjacent to DCC 102 and / or is a distinct component, positioned external to housing 1 10 of DCC 102. Mist eliminator 128 is formed from any suitable device or assembly that facilitates removing liquid droplets and / or moisture from exhaust gases 36 flowing through DCC 102. As described herein, mist eliminator 128 of DCC 102 is a passive or fail-safe component that only become operational if WESP 124 becomes inoperable.

[0041] A fluid collection section 130 of housing 110 is opposite WESP 124. More specifically, in the exemplary' embodiment, housing 110 of DCC 102 also includes fluid collection section 130 positioned adjacent to inlet section 112 of housing 110, and opposite WESP 124 and / or mist eliminator 128. Fluid collection section 130 of housing 110 receives cooling fluid 120 that is sprayed and / or misted over exhaust gases 36 via sprayer array(s) 118 during operation of DCC 102. As discussed herein cooling fluid 120 collected and / or received within fluid collection section 130 of housing 110 is recirculated back to sprayer array(s) 118. Additionally, cooling fluid 120 used to treat exhaust gases 36 flowing through DCC 102 can absorb contaminants, impurities, and / or chemicals removed from exhaust gases 36. As such, a contaminant correction reservoir 132 (hereafter, “CC reservoir 132”) is fluidly coupled and / or in flow communication with fluid collection section 130 of housing 110. CC reservoir 132 can provide any suitable material that facilitates adjusting characteristics of cooling fluid 120 and / or remove undesirable contaminants or impurities imparted to cooling fluid 120 while fluid treated exhaust gases 36 within DCC 102. For example, CC reservoir 132 can include a material or reagent configured to be mixed with cooling fluid 120 received in fluid collection section 130 to facilitate adjusting or correcting the pH level of cooling fluid 120. pnor to cooling fluid 120 being recirculated back to sprayer array(s) 118, as described herein. In another non-limiting example, CC reservoir 132 may include a reagent that facilitates the removal of contaminants or impurities absorbed by cooling fluid 120 utilized within DCC 102. In non-limiting examples, the reagent included within CC reservoir 132 and provided to fluid collection section 130 of housing 110 for DCC 102 can be formed from any suitable chelating agent including sulfides and / or sulfites. Additionally, or alternatively, the reagent can include, but is not limited to only including, hydrogen peroxide, plasma, sodium hydroxide (NaOH), and / or ammonium hydroxide (NH4OH).(17851-1506)

[0042] As described herein, cooling fluid 120 is continuously collected and / or received within fluid collection section 130 and resupplied to sprayer array(s) 118 positioned within housing 110 of DCC 102 to facilitate treating exhaust gases 36. In the exemplary embodiment, EGR assembly 100 / DCC 102 includes fluid recirculation system including a return conduit 134 in flow communication with fluid collection section 130 of housing 110, a heat exchanger 136 in flow communication with return conduit 134, and a supply conduit 138 in flow communication with heat exchanger 136 and sprayer array(s) 118, respectively. Return conduit 134 and supply conduit 138 fluidly couple and / or facilitate flow communication between DCC 102 and heat exchanger 136. During operation, heat exchanger 136 facilitates the flowing of re-cooled cooling fluid 120 to DCC 102. That is, cooling fluid 120 is utilized within housing 110 of DCC 102 to facilitate the treating of exhaust gases 36, where cooling fluid 120 absorbs at least a portion of the heat from exhaust gases 36, and is subsequently collected or received within fluid collection section 130 of housing 110. Return conduit 134. in flow communication with fluid collection section 130 of housing 110, flows received cooling fluid 120 back to heat exchanger 136, where cooling fluid 120 is re-cooled in preparation for additional supply to sprayer array(s) 118 positioned within housing 110. A recirculation pump 140, in flow communication with return conduit 134. facilitates the flowing and / or providing of cooling fluid 120 from fluid collection section 130 of housing 110 back to heat exchanger 136.

[0043] In a non-limiting example, EGR assembly 100 also includes a bypass valve 142 formed on a bypass conduit 144. Bypass conduit 144 extends between and facilitates the flow communication between return conduit 134 and supply conduit 138 of EGR assembly 100. In a non-limiting example where exhaust gases 36 does not require substantially cooling and / or sprayer array(s) 118 of DCC 102 do not require cooling fluid 120 to be substantially cooled before being sprayed within housing 110, bypass valve 142 allows at least a portion of cooling fluid 120 to bypass heat exchanger 136, before being flowed back to DCC 102. In the example, bypassed cooling fluid 120 can have a higher temperature than cooling fluid 120 flowed from heat exchanger 136. Cooling fluid 120 flowed from return conduit 134 to supply conduit 138 via bypass conduit 144 can mix with cooling fluid 120 flowed directly from heat exchanger 136 to supply conduit 138 and increase the overall temperature of cooling fluid 120 in supply conduit 138, prior to cooling fluid 120 reaching DCC 102. This process can ensure exhaust gases 36 channeled through DCC 102 are not(17851-1506) overcooled and / or the temperature is decreased such that exhaust gases 36 includes a temperature that is below a desired temperature for recirculation, as described herein.

[0044] EGR assembly 100 also includes a blowdown conduit 146. In the non-limiting example shown in FIG. 2, blowdown conduit 146 is in flow communication with return conduit 134, and upstream from heat exchanger 136 and bypass conduit 144, respectively. Blow dow n conduit 146 facilitates the removal of large particles, contaminants, and / or byproducts generated and / or removed from exhaust gases 36 when treating exhaust gases 36 within housing 110 of DCC 102.

[0045] Once treated within DCC 102, exhaust gases 36 are recirculated back to GT system 30 of power plant 12. More specifically, after being cooled to a desired temperature and / or having contaminants and impurities removed using the various components included within single housing 110 of DCC 102, exhaust gases 36 are channeled from DCC 102 to recirculation conduit 68, and subsequently are supplied to compressor 32 of GT system 30. As described herein, the recirculation of exhaust gases 36 treated within housing 110 of DCC 102 back to compressor 32 facilitates improving and / or optimizing the operation of GT system 30 and / or powder plant 12.

[0046] In addition, or alternative, to CC reservoir 132, EGR assembly 100 may also include a pH correction reservoir 148. In a non-limiting example, pH correction reservoir 148 is fluidly coupled and / or in flow- communication with return conduit 134. In other exemplary embodiments, pH correction reserv oir 148 is fluidly coupled and / or in flow communication with heat exchanger 136, and / or supply conduit 138. PH correction reserv oir 138 can provide any suitable material that facilitates adjusting the pH level of cooling fluid 120 for treating exhaust gases 36 within DCC 102. For example, pH correction reservoir 148 can include a reagent configured to be mixed with cooling fluid 120 to facilitate adjusting or correcting the pH level of cooling fluid 120, prior to cooling fluid 120 being recirculated back to sprayer array(s) 118, as described herein. In nonlimiting examples, the reagent included within pH correction reservoir 148 and provided to cooling fluid 120 within EGR assembly 100 can include, but is not limited to, sodium hydroxide (NaOH), magnesium hydroxide (Mg(OH)2), and / or ammonium hydroxide (NH4OH).(17851-1506)

[0047] FIGs. 3 and 4 show non-limiting examples 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.

[0048] In the non-limiting example shown in FIG. 3, DCC 102 includes a plurality of packed beds 122A, 122B. Packed bed 122A is within housing 1 10 between first sprayer array 118A and second sprayer array 118B, respectively. Additionally, a distinct packed bed 122B is also within housing 110, adjacent first sprayer array 118A. More specifically, distinct packed bed 122B is within housing 110. upstream from first sprayer array 118A and downstream from inlet section 112 of housing 1 10. In the non-limiting example shown in FIG. 3, exhaust gases 36 may pass or flow through both packed beds 122A, 122B within housing 110 of DCC 102 to facilitate the cooling of exhaust gases 36, as similarly described herein.

[0049] FIG. 4 shows a non-limiting example of EGR assembly 100, where mist eliminator 128 is independent of DCC 102. That is, mist eliminator 128 is not included within housing 110 of DCC 102, but rather is on recirculation conduit 68 of power plant 12. More specifically, and as shown in FIG. 4, mist eliminator 128 is on and in direct flow communication with recirculation conduit 68, separate from housing 110 of DCC 102.Additionally in the non-limiting example, mist eliminator 128 is between DCC 102 of EGR assembly 100 and compressor 32 of GT system 30, and / or is dow nstream from DCC 102 and upstream from compressor 32, respectively. As described herein, mist eliminator 128 is a passive component and / or failsafe component for EGR assembly 100, and may only be activated when it is determined that WESP 124 is inoperable during operation of EFR assembly 100.

[0050] FIG. 5 illustrates an exemplary' process for treating exhaust gases. Specifically, FIG. 5 is a flow chart depicting an exemplary' process for treating exhaust gases generated by a heat recover steam generator (HRSG) of a combined cycle power plant system using a direct contact cooler (DCC) included in an exhaust gas recirculation (EGR) assembly. In some cases, the processes can be performed using system 10, powder plant 12, and EGR assembly 100 including DCC 102, as described above w ith respect to FIGs. 1-4.(17851-1506)

[0051] In process Pl, exhaust gas(es) are channeled through DCC. More specifically, exhaust gas(es) generated by HRSG of a power plant are channeled through a housing of the DCC for the ERG assembly. In a non-limiting example, the exhaust gas(es) are routed into the housing of the DCC via an inlet section of the housing.

[0052] In process P2, the exhaust gas(es) are cooled. That is, exhaust gas(es) flowing through and / or within the housing of the DCC are facilitated to be cooled and / or reduced in temperature. The exhaust gas(es) are cooled using a cooling fluid. In a non-limiting example, cooling the exhaust gas(es) can include spraying the exhaust gas(es) with the cooling fluid using a first sprayer array within the housing DCC, attached to and downstream from the inlet section of the housing. Additionally, cooling the exhaust gas(es) can include spraying the exhaust gas(es) with the cooling fluid using a second sprayer array within the housing the DCC. In the non-limiting example, the second sprayer array is downstream from the first sprayer array.

[0053] Additionally, cooling the exhaust gas(es) flowing through and / or within the housing of the DCC is facilitated using at least one packed bed within the DCC. The temperature of the exhaust gas(es) is lowered and / or reduced as it flows through the packed bed. The at least one packed bed is adjacent to the at least one sprayer array. In a non-limiting example a packed bed is between the first sprayer array and the second sprayer array, and / or is downstream from the first sprayer array and upstream from the second sprayer array. Additionally, or alternatively, a distinct packed bed can be within the housing, adjacent to and upstream from, the first sprayer array.

[0054] In process P3, at least one contaminant is removed from the exhaust gas(es). More specifically, at least one contaminant entrained within the exhaust gas(es) is removed using the at least one sprayer array within the housing the DCC. The contaminants are removed from the exhaust gas(es) as it flows through the DCC, and is sprayed and / or saturated with the cooling fluid. In the non-limiting example, the contaminants included within the exhaust gas(es) are removed from the exhaust gas(es) and / or trapped within the cooling fluid.

[0055] In process P4, at least one distinct contaminant is removed from the exhaust gas(es). More specifically, at least one distinct contaminant included within the exhaust gas(es) is removed using a wet electrostatic precipitator (WESP) within the housing of the DCC. The contaminants are removed from the exhaust gas(es) as it flows through the(17851-1506)WESP and are trapped therein. In non-limiting examples, the WESP is within the housing of the DCC. More specifically, the WESP is downstream from the at least one sprayer array and the at least one packed bed within the DCC.

[0056] Although shown and discussed herein as being performed in order (e.g., processes P1-P4). it is understood that at least two of the processes can be performed in any order and / or can be performed concurrently. For example, spraying the exhaust gas(es) with the cooling fluid using the second sprayer array, (e.g., process P2) may simultaneously cool the exhaust gas(es) and remove the contaminant included within the exhaust gas(es) (e.g., process P3). Subsequently, the exhaust gas(es) can continue to be cooled using the second sprayer array and / or at least one packed bed, as discussed herein.

[0057] At least one technical effect is to provide a combined cycle power plant that includes an exhaust gas recirculation assembly that includes a direct contact cooler (DCC) that combines multiple components for cooling and removing contaminants from exhaust gas(es) and requires less space or foot print than conventional DCCs.

[0058] 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.

[0059] 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.(17851-1506)

[0060] 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,” 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).

[0061] 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.

[0062] Exemplary direct contact coolers (DCCs), exhaust gas recirculation assemblies, system, and methods for treating and recirculating exhaust gas within the power plant are described herein. Moreover, the devices, assemblies, systems, and methods 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, while also reducing the space and / or footprint required for DCCs within the power plant. The exemplary' devices, assemblies, systems, and methods, as described herein, provide several advantages over conventional designs and processes, including increasing the operational efficiency and performance of a gas turbine(17851-1506) 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 devices, assemblies, systems, and methods facilitate treating (e g., cooling, removing contaminants) the exhaust gases within a single housing DCC that includes all required components for treatment, before recirculating the treated, exhaust gases back to the gas turbine system of the power plant. 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. Additionally, by combining multiple components for treating exhaust gases into a single housing of the DCCs, physical space i.e., the footprint, required for the DCC within the EGR assemblies and / or overall power plant is facilitated to be reduced. Furthermore, the use of a single housing DCC for treating the exhaust gases also aids in maintaining flow rates of the exhaust gases, as the exhaust gases are not flowed through multiple, distinct components and / or systems and pass through multiple conduits including turns, to be treated by the multiple, distinct components, as is understood in conventional systems and designs.

[0063] 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.

[0064] 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 wi th 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.(17851-1506)

[0065] Further aspects of the invention are provided by the subject matter of the following clauses: A direct contact cooler (DCC), comprising a housing including an inlet section in flow communication with a heat recovery steam generator (HRSG), the inlet section oriented to receive exhaust gases generated in the HRSG; at least one sprayer array within the housing, adjacent to, and downstream from, the inlet section, the at least one sprayer array configured to spray a cooling fluid within the housing; at least one packed bed within the housing and adjacent to the at least one sprayer array; and a wet electrostatic precipitator (WESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

[0066] The DCC in accordance with any of the preceding clauses, further comprising a mist eliminator within the housing, adjacent to, and downstream from, the WESP.

[0067] The DCC in accordance with any of the preceding clauses, wherein the at least one sprayer array further includes: a first sprayer array within the housing, adjacent to, and downstream from, the inlet section of the housing; and a second sprayer array positioned within the housing and downstream from the first sprayer array.

[0068] The DCC in accordance with any of the preceding clauses, wherein the at least one packed bed is between the first sprayer array and the second sprayer array.

[0069] The DCC in accordance with any of the preceding clauses, further comprising a distinct packed bed within the housing, the distinct packed bed upstream from the first sprayer array and downstream from the inlet section of the housing.

[0070] The DCC in accordance with any of the preceding clauses, wherein the housing further includes a fluid collection section adjacent to the inlet section and opposite the WESP. the fluid collection section oriented to receive the cooling fluid sprayed by the at least one sprayer array within the housing.

[0071] The DCC in accordance with any of the preceding clauses, further comprising: a return conduit in flow communication with the fluid collection section of the housing, the return conduit oriented to receive the cooling fluid from the fluid collection section; a heat exchanger in flow communication with the return conduit, the heat exchanger oriented to receive the cooling fluid from the return conduit; and a supply conduit in flow communication with the heat exchanger and the at least one sprayer array, the supplyconduit oriented to supply the cooling fluid to the at least one sprayer array.(17851-1506)

[0072] The DCC in accordance with any of the preceding clauses, wherein the housing further includes a maintenance access area defined between the at least one sprayer array and the WESP, the maintenance access area sized to provide access to the WESP from within the housing.

[0073] A combined cycle power plant, comprising a heat recovery steam generator (HRSG) in flow communication with a gas turbine system, the HRSG configured to generate exhaust gases; and an exhaust gas recirculation (EGR) assembly downstream from and in flow communication with the HRSG for receiving at least a portion of the exhaust gases, the EGR assembly including: a direct contact cooler (DCC) in flow communication with and upstream from the gas turbine system, the DCC including: a housing including an inlet section in flow communication with the HRSG, the inlet section oriented to receive at least the portion of the exhaust gases generated in the HRSG; at least one sprayer array within the housing, adjacent to, and downstream from the inlet section, the at least one sprayer array configured to spray a cooling fluid within the housing; at least one packed bed within the housing and adjacent to the at least one sprayer array; and an electrostatic precipitator (ESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

[0074] The combined cycle power plant in accordance with any of the preceding clauses, further comprising a recirculation conduit in flow communication with and fluidly coupling the DCC and the gas turbine system.

[0075] The combined cycle power plant in accordance with any of the preceding clauses, wherein the DCC further includes a mist eliminator downstream from the WESP and one of: within the housing of the DCC. or on and in direct flow communication with the recirculation conduit, separate from the housing of the DCC.

[0076] The combined cycle power plant in accordance with any of the preceding clauses, wherein the at least one sprayer array of the DCC further includes: a first sprayer array within the housing, adjacent to, and downstream from, the inlet section of the housing; and a second sprayer array within the housing and downstream from the first sprayer array.

[0077] The combined cycle pow er plant in accordance with any of the preceding clauses, wherein the at least one packed bed of the DCC is between the first sprayer array and the second sprayer array.(17851-1506)

[0078] The combined cycle power plant in accordance with any of the preceding clauses, wherein the DCC further includes a distinct packed bed within the housing, the distinct packed bed upstream from the first sprayer array and downstream from the inlet section of the housing.

[0079] The combined cycle power plant in accordance with any of the preceding clauses, wherein the housing of the DCC further includes a fluid collection section adjacent to the inlet section and opposite the WESP, the fluid collection section oriented to receive the cooling fluid sprayed by the at least one sprayer array within the housing.

[0080] The combined cycle power plant in accordance with any of the preceding clauses, wherein the DCC further includes: a return conduit in flow communication with the fluid collection section of the housing, the return conduit oriented to receive the cooling fluid from the fluid collection section; a heat exchanger in flow communication with the return conduit, the heat exchanger oriented to receive the cooling fluid from the return conduit; and a supply conduit in flow communication with the heat exchanger and the at least one sprayer array, the supply conduit oriented to supply the cooling fluid to the at least one sprayer array.

[0081] The combined cycle power plant in accordance with any of the preceding clauses, wherein the housing of the DCC further includes a maintenance access area defined between the at least one sprayer array and the WESP, the maintenance access area sized to provide access to the WESP from within the housing.

[0082] A method for treating exhaust gases generated by a heat recovery steam generator (EIRSG), comprising channeling exhaust gases generated by the EIRSG through a housing of a direct contact cooler (DCC); cooling the exhaust gases within the housing using a cooling fluid provided by at least one sprayer array within the housing of the DCC; removing a contaminant entrained within the exhaust gases using the cooling fluid provided by the at least one sprayer array within the housing of the DCC ; and removing at least one of a distinct contaminant or moisture from the exhaust gases using a wet electrostatic precipitator (WESP) within the housing of the DCC, the WESP being downstream from the at least one sprayer array of the DCC.

[0083] The method in accordance with any of the preceding clauses, wherein the cooling of the exhaust gases within the housing further includes: spraying the exhaust gases with cooling fluid using a first sprayer array within the housing of the DCC; and spraying the700673-WO-l(17851-1506) exhaust gases with the cooling fluid using a second sprayer array within the housing of the DCC. the second sprayer array downstream from the first sprayer array and upstream from the WESP.

[0084] The method in accordance with any of the preceding clauses, wherein prior to spraying the exhaust gases with the cooling fluid using the second sprayer array, reducing a temperature of the exhaust gases using a packed bed within the housing, the packed bed between the first sprayer array and the second sprayer array.

Claims

(17851-1506)CLAIMSWhat is claimed is:

1. A direct contact cooler (DCC), comprising: a housing including an inlet section in flow communication with a heat recovery steam generator (HRSG), the inlet section oriented to receive exhaust gases generated in the HRSG; at least one sprayer array within the housing, adjacent to, and downstream from, the inlet section, the at least one sprayer array configured to spray a cooling fluid within the housing; at least one packed bed within the housing and adjacent to the at least one sprayer array; and a wet electrostatic precipitator (WESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

2. The DCC of claim 1, further comprising a mist eliminator within the housing, adjacent to. and downstream from, the WESP.

3. The DCC of claim 1, wherein the at least one sprayer array further includes: a first sprayer array within the housing, adjacent to, and downstream from, the inlet section of the housing; and a second sprayer array positioned within the housing and downstream from the first sprayer array.

4. The DCC of claim 3, wherein the at least one packed bed is between the first sprayer array and the second sprayer array.

5. The DCC of claim 4, further comprising a distinct packed bed within the housing, the distinct packed bed upstream from the first sprayer array and downstream from the inlet section of the housing.(17851-1506)6. The DCC of claim 1. wherein the housing further includes a fluid collection section adjacent to the inlet section and opposite the WESP, the fluid collection section oriented to receive the cooling fluid sprayed by the at least one sprayer array within the housing.

7. The DCC of claim 6, further comprising: a return conduit in flow communication with the fluid collection section of the housing, the return conduit oriented to receive the cooling fluid from the fluid collection section; a heat exchanger in flow communication with the return conduit, the heat exchanger oriented to receive the cooling fluid from the return conduit; and a supply conduit in flow communication with the heat exchanger and the at least one sprayer array, the supply conduit oriented to supply the cooling fluid to the at least one sprayer array.

8. The DCC of claim 1, wherein the housing further includes a maintenance access area defined between the at least one sprayer array and the WESP, the maintenance access area sized to provide access to the WESP from within the housing.

9. A combined cycle power plant, comprising: a heat recovery steam generator (HRSG) in flow communication with a gas turbine system, the HRSG configured to generate exhaust gases; and an exhaust gas recirculation (EGR) assembly downstream from and in flow communication with the HRSG for receiving at least a portion of the exhaust gases, the EGR assembly including: a direct contact cooler (DCC) in flow' communication with and upstream from the gas turbine system, the DCC including: a housing including an inlet section in flow communication with the HRSG, the inlet section oriented to receive at least the portion of the exhaust gases generated in the HRSG; at least one sprayer array within the housing, adjacent to, and downstream from the inlet section, the at least one sprayer array configured to spray a cooling fluid within the housing;(17851-1506) at least one packed bed within the housing and adjacent to the at least one sprayer array; and a wet electrostatic precipitator (WESP) within the housing, downstream from the at least one sprayer array and the at least one packed bed.

10. The combined cycle power plant of claim 9, further comprising a recirculation conduit in flow communication with and fluidly coupling the DCC and the gas turbine system.

11. The combined cycle power plant of claim 10, wherein the DCC further includes a mist eliminator downstream from the WESP and one of: within the housing of the DCC, or on and in direct flow communication with the recirculation conduit, separate from the housing of the DCC.

12. The combined cycle power plant of claim 9, wherein the at least one sprayer array of the DCC further includes: a first sprayer array within the housing, adjacent to, and downstream from, the inlet section of the housing; and a second sprayer array within the housing and downstream from the first sprayer array.

13. The combined cycle pow er plant of claim 12, wherein the at least one packed bed of the DCC is between the first sprayer array and the second sprayer array.

14. The combined cycle power plant of claim 13, wherein the DCC further includes a distinct packed bed within the housing, the distinct packed bed upstream from the first sprayer array and downstream from the inlet section of the housing.(17851-1506)15. The combined cycle power plant of claim 9. wherein the housing of the DCC further includes a fluid collection section adjacent to the inlet section and opposite the WESP, the fluid collection section oriented to receive the cooling fluid sprayed by the at least one sprayer array within the housing.

16. The combined cycle power plant of claim 15, wherein the DCC further includes: a return conduit in flow communication with the fluid collection section of the housing, the return conduit oriented to receive the cooling fluid from the fluid collection section; a heat exchanger in flow communication with the return conduit, the heat exchanger oriented to receive the cooling fluid from the return conduit; and a supply conduit in flow communication with the heat exchanger and the at least one sprayer array, the supply conduit oriented to supply the cooling fluid to the at least one sprayer array.

17. The combined cycle power plant of claim 9, wherein the housing of the DCC further includes a maintenance access area defined between the at least one sprayer array and the WESP. the maintenance access area sized to provide access to the WESP from within the housing.

18. A method for treating exhaust gases generated by a heat recovery steam generator (HRSG), the method comprising: channeling exhaust gases generated by the HRSG through a housing of a direct contact cooler (DCC); cooling the exhaust gases within the housing using a cooling fluid provided by at least one sprayer array within the housing of the DCC; removing a contaminant entrained within the exhaust gases using the cooling fluid provided by the at least one sprayer array within the housing of the DCC ; and removing at least one of a distinct contaminant or moisture from the exhaust gases using a wet electrostatic precipitator (WESP) within the housing of the DCC, the WESP being downstream from the at least one sprayer array of the DCC.-SO-PCT700673-WO-l(17851-1506)19. The method of claim 18, wherein the cooling of the exhaust gases within the housing further includes: spraying the exhaust gases with cooling fluid using a first sprayer array within the housing of the DCC; and spraying the exhaust gases with the cooling fluid using a second sprayer array within the housing of the DCC, the second sprayer array downstream from the first sprayer array and upstream from the WESP.

20. The method of claim 19, wherein prior to spraying the exhaust gases with the cooling fluid using the second sprayer array, reducing a temperature of the exhaust gases using a packed bed within the housing, the packed bed between the first sprayer array and the second sprayer array.

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