A heat exchanger comprising a heat exchange tube movable between an aligned position and a misaligned position

Abstract

To provide a heat exchanger with adjustability of the positions of heat exchange tubes.SOLUTION: A heat exchanger 108 includes a plurality of heat exchange tubes arranged in a first row of tubes 180A, 180C and a second row of tubes 180B. A fixed mount 182 fixedly positions the first row of tubes 180A, 180C, and a movable mount 190 makes the second row of tubes 180B movable between an aligned position, in which the tubes 180B in the second row are aligned with the tubes 180A, 180C in the first row thereby creating a linear flow path 196 for a fluid 142 passing through the tubes 180A, 180B, 180C, and a non-aligned position, in which the tubes 180B in the second row are not aligned with the heat tubes 180A, 180C in the first row thereby creating a curvilinear flow path for the fluid 142 passing through the plurality of tubes 180A, 180B, 180C. Heat is exchanged between the first fluid 142 and a second fluid that pass through the plurality of heat exchange tubes.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure generally relates to heat exchangers, and more specifically, to heat exchangers including tubes in a row that can be aligned or misaligned with heat exchange tubes in another row, and including heat exchange tubes that form linear or curved flow paths for fluids passing through the heat exchanger.

Background Art

[0002] Convection heat exchangers include multiple rows of heat exchange tubes fixed in either a staggered or non-aligned configuration, or an in-line or aligned configuration. Managing the operation of a heat exchanger with a fixed arrangement of heat exchange tubes presents numerous challenges. Although applicable to any heat exchanger, for purposes of explaining the problems and advantages of embodiments of the present disclosure, the present disclosure considers heat exchangers in the form of heat recovery steam generators (HRSGs) in combined cycle power plants (CCPPs) including gas turbine (GT) systems and steam turbine (ST) systems. In this setting, the effectiveness of the HRSG varies depending on a number of operating parameters. In the example of a CCPP, the incoming heat may vary depending on operating parameters such as, but not limited to, the load of the GT system, the ambient temperature, the degradation of the GT system, the modification / upgrade of the GT system, the load of the duct burner, and the deviation between the expected and actual operation. Similarly, the heat exchange efficiency within the HRSG can vary depending on operating parameters of the HRSG such as its cleanliness.

[0003] A heat exchanger with a fixed arrangement of its heat exchange tubes cannot be adjusted to cope with the above variations. Second, in a CCPP, during startup of the ST system, it is typically necessary to reduce the steam temperature to reduce thermal fatigue that may affect the average life of the equipment. With a fixed heat exchange tube arrangement, complex control, such as controlling the steam temperature through control of the exhaust temperature or flow rate input of the GT system, steam / water flow, etc., is required. Third, cleaning of the heat exchange tubes in an HRSG can be difficult. For example, a staggered heat exchange tube arrangement is often desirable because it is more compact, but as a result, access to the heat exchange tubes positioned inside is lost, making cleaning of such an arrangement very difficult. Finally, a fixed heat exchange tube arrangement can result in unwanted noise due to resonance of the vortex shedding frequency. SUMMARY OF THE INVENTION

[0004] A first aspect of the present disclosure is a casing configured to pass a first fluid, a plurality of heat exchange tubes fluidly coupled to a header and positioned within the casing, the plurality of heat exchange tubes including a plurality of heat exchange tubes arranged in a first row of tubes and a second row of tubes, a fixed mount fixedly positioning the first row of tubes relative to the casing, and a movable mount operably coupled to the second row of tubes, the movable mount being in an aligned position where the heat exchange tubes in the second row of tubes are aligned with the heat exchange tubes in the first row of tubes and forming a linear flow path for the first fluid passing through the plurality of heat exchange tubes, and a non-aligned position where the heat exchange tubes in the second row of tubes are not aligned with the heat exchange tubes in the first row of tubes and forming a curved flow path for the first fluid passing through the plurality of heat exchange tubes, and being movable between the two positions, and heat is exchanged between the first fluid passing through the plurality of heat exchange tubes and a second fluid, providing a heat exchanger.

[0005] A second aspect of the present disclosure provides a combined cycle power plant comprising a gas turbine system, a steam turbine system, and a heat recovery steam generator (HRSG) coupled to the gas turbine system and configured to use the exhaust of the gas turbine system to generate steam for the steam turbine system. The HRSG includes a casing configured to pass exhaust therethrough, and a plurality of heat exchange tubes fluidly coupled to a water / steam header and positioned within the casing. The plurality of heat exchange tubes includes a plurality of heat exchange tubes arranged in a first row of tubes and a second row of tubes, a fixed mount fixedly positioning the first row of tubes relative to the casing, and a movable mount operatively coupled to the second row of tubes. The movable mount is movable between an aligned position in which the heat exchange tubes in the second row of tubes are aligned with the heat exchange tubes in the first row of tubes, forming a linear flow path for the exhaust passing through the plurality of heat exchange tubes, and a misaligned position in which the heat exchange tubes in the second row of tubes are not aligned with the heat exchange tubes in the first row of tubes, forming a curved flow path for the exhaust passing through the plurality of heat exchange tubes. Heat is exchanged between the exhaust passing through the plurality of heat exchange tubes and a water / steam flow.

[0006] A third aspect of the present disclosure is a method for operating a heat recovery steam generator (HRSG) of a combined cycle power plant (CCPP), the HRSG including a plurality of heat exchange tubes arranged in columns, the HRSG being part of a system including a gas turbine (GT) system and a steam turbine (ST) system, the method comprising measuring at least one operating parameter of at least one of the HRSG, the gas turbine (GT) system of the CCPP, and the steam turbine (ST) system of the CCPP, and in response to at least one operating parameter not meeting a threshold value, moving a row of a first plurality of heat exchange tubes relative to a fixed row of a second plurality of heat exchange tubes between an aligned position where heat exchange tubes in the row of the second plurality of heat exchange tubes are aligned with heat exchange tubes in the row of the first plurality of heat exchange tubes and form a linear flow path for a first fluid passing through the plurality of heat exchange tubes, and a non-aligned position where heat exchange tubes in the row of the second plurality of heat exchange tubes are not aligned with heat exchange tubes in the row of the first plurality of heat exchange tubes and form a curved flow path for the first fluid passing through the plurality of heat exchange tubes, wherein heat is exchanged between the first fluid and a second fluid passing through the plurality of heat exchange tubes, and providing the method.

[0007] Exemplary aspects of the present disclosure are designed to solve the problems described herein and / or other problems not considered.

[0008] These and other features of the present disclosure will be more readily understood from the following detailed description of the various aspects of the present disclosure in conjunction with the accompanying drawings that illustrate various embodiments of the present disclosure.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

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Figure 10

MODE FOR CARRYING OUT THE INVENTION

[0010] It should be noted that the drawings of the present disclosure are not necessarily drawn to scale. The drawings are intended to illustrate only typical aspects of the present disclosure and should not be considered as limiting the scope of the present disclosure. In the drawings, like reference numerals represent like elements among the drawings.

[0011] As a first issue, when referring to and describing components in exemplary applications in the form of a combined cycle power plant and its components to clearly explain the current technology, it is necessary to select certain specialized terms. To the extent possible, general industrial specialized terms are used and utilized in the same meaning as their accepted meaning. Unless otherwise stated, such specialized terms should be given a broad interpretation consistent with the context of this application and the appended claims. One of ordinary skill in the art will, in many cases, understand that a particular component may be referred to using several different or overlapping terms. What may be described herein as a single component may include other contexts as consisting of a plurality of components and may be referred to in another context. Alternatively, what may be described herein as including a plurality of components may be referred to elsewhere as a single component.

[0012] In addition, several descriptive terms can be used regularly in this specification, and it can be seen that it is useful to define these terms at the beginning of this section. These terms and their definitions are as follows, unless otherwise stated. As used herein, "downstream" and "upstream" are terms indicating directions with respect to the flow of a fluid, such as the working fluid passing through a turbine engine, or, for example, the flow of hot gas passing through a heat exchanger. The term "downstream" corresponds to the direction of the fluid flow, and the term "upstream" refers to the opposite direction of the flow. The terms "front" and "rear" refer to directions, unless otherwise specified, where "front" refers to the front of the engine or the compressor end, and "rear" refers to the rear of the engine or the turbine end.

[0013] Often, it is required to describe components located at different radial positions with respect to a central axis. The term "radial" refers to movement or position perpendicular to the axis. In such cases, if a first component is located closer to the axis than a second component, then in this specification, it is stated that the first component is "radially inward" or "inner" of the second component. On the other hand, if a first component is located farther from the axis than a second component, then in this specification, it can be stated that the first component is "radially outward" or "outer" of the second component. The term "axial" refers to movement or position parallel to the axis. Finally, the term "circumferential" refers to movement or position around the axis. It will be understood that such terms can be applied in relation to the central axis of a turbine.

[0014] In addition, as described below, several descriptive terms can be used regularly in this specification. The terms "first", "second", and "third" can be used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0015] The technical terms used in this specification are merely for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless specifically stated otherwise. The terms "comprise" and / or "comprising", as used herein, specify the presence of the described 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 combinations thereof. "Optional" or "optionally" means that the event or circumstance described later may or may not occur, and this description means that it includes cases where the event occurs and cases where it does not occur.

[0016] When an element or layer is referred to as being "on," "engaged with," "connected to," or "coupled to" another element or layer, it may be directly on, engaged with, connected to, or coupled to the other element or layer, or intervening elements or layers may be present. Conversely, when an element is referred to as being "directly on," "directly engaged with," "directly connected to," or "directly coupled to" another element or layer, intervening elements or layers may not be present. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., "directly between" for "between," "directly adjacent to" for "adjacent to," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0017] As shown above, the present disclosure provides a heat exchanger having adjustability in the position of heat exchange tubes. The heat exchanger may include a plurality of heat exchange tubes arranged in a row of tubes. A fixed mount fixedly positions a fixed row of tubes, and a movable mount enables another row of tubes to be movable between an aligned position and a misaligned position. In the aligned position, the tubes in the movable row are aligned or in a row with the tubes in the fixed row of tubes, forming a linear flow path for the fluid passing through the tubes. In the misaligned position, the tubes in the movable row are not aligned or are staggered with the tubes in the fixed row, forming a curved flow path for the fluid passing through the plurality of tubes. Heat can be exchanged between a first fluid and a second fluid passing through the plurality of heat exchange tubes regardless of the position.

[0018] Referring to FIG. 1, a heat exchanger according to an embodiment of the present disclosure is described in relation to an exemplary application in the form of a combined cycle power plant (CCPP) 100. FIG. 1 shows a schematic diagram of the CCPP 100. It is emphasized that the teachings of the present disclosure are applicable to any heat exchanger. The CCPP 100 may include a gas turbine (GT) system 102 operably connected to a generator 104 and a steam turbine (ST) system 110 operably coupled to another generator 112. The generator 104 and the GT system 102 can be mechanically coupled by a shaft 106, and the shaft 106 can transmit energy between a drive shaft (not shown) of the GT system 102 and the generator 104. In an exemplary application, the CCPP 100 is a single-shaft system with two generators, but those skilled in the art will readily understand that the teachings of the present disclosure are applicable to any variety of combined cycle power generation systems.

[0019] Also, as shown in FIG. 1, the heat exchanger 108 is operably connected to the GT system 102 and the ST system 110. As will be described in more detail herein, the heat exchanger 108 may include a heat recovery steam generator (HRSG) including adjustable positioning of heat exchange tubes according to an embodiment of the present disclosure. The heat exchanger 108 can be fluidly connected to both the GT system 102 and the ST system 110 via conventional conduits (reference numerals are omitted).

[0020] It is understood that the generators 104, 112 and the shaft 106 may be of any size or type known in the art and may vary depending on their application or the system to which they are connected. The common reference numerals for the generators and the shaft are for clarity and do not necessarily imply that these generators or shafts are the same.

[0021] The GT system 102 can include a compressor 120 and a combustor 124. The combustor 124 includes a combustion region 126 and a fuel nozzle assembly 128. The GT system 102 also includes a gas turbine 130 coupled to a common compressor / turbine shaft 106. In one embodiment, the GT system 102 can be an MS7001FB engine, sometimes referred to as a 9FB engine, commercially available from General Electric of Greenville, South Carolina. The present disclosure is not limited to any particular GT system and can be implemented in connection with other engines, including, for example, General Electric's MS7001FA (7FA) and MS9001FA (9FA) engine models.

[0022] During operation, air enters the inlet of the compressor 120, is compressed and discharged into the combustor 124, where fuel such as gas, e.g., natural gas, or a fluid, e.g., oil, is burned to provide high-energy combustion gases that drive the gas turbine 130. In the gas turbine 130, the energy of the hot gas is converted into work, a portion of which is used to drive the compressor 120 through the rotating shaft 106, and the remainder is available for useful work to drive a load, such as a generator 104 for generating electricity, through the shaft 106.

[0023] FIG. 1 also depicts the CCPP 100 in its simplest form in which the energy in the exhaust gas exiting the gas turbine 130 is converted into further useful work. The exhaust gas enters a heat exchanger 108 in the form of a HRSG, where water is converted into steam in a boiler fashion. The heat exchanger 108 can also use energy to produce high-temperature feed water having a temperature in the range of, for example, 95° C. to 99° C.

[0024] The ST system 110 may include one or more steam turbines. For example, the ST system 110 may include a high pressure (HP) turbine 132, an intermediate pressure (IP) turbine 134, and a low pressure (LP) turbine 136, each of which is coupled to the shaft 106. Each steam turbine 132, 134, 136 includes a plurality of rotating blades (not shown) mechanically coupled to the shaft 106. During operation, the heat exchanger 108, and often steam from other sources, enters the inlets of the HP turbine 132, IP turbine 134, and / or LP turbine 136 and is directed to exert force on their blades to rotate the shaft 106. As will be appreciated, steam from an upstream turbine can be used later in a downstream turbine. In this way, the steam generated by the heat exchanger 108 drives at least a portion of the ST system 110, additional work is extracted to drive the shaft 106, and then a further load such as a second generator 112 generates additional power. In some configurations, the turbines 130, 132, 134, 136 drive a common generator.

[0025] FIG. 1 also shows a CCPP control system 138 operably coupled to the GT system 102, the heat exchanger (i.e., HRSG) 108, and the ST system 110. The control system 138 may include any currently known or later developed computerized controller for providing automatic control of the CCPP 100. As will be explained, the control system 138 can execute the methods according to embodiments of the present disclosure.

[0026] Figures 2 and 3 show partial transparent perspective views of an embodiment of the heat exchanger 108. The heat exchanger 108 is shown as a HRSG coupled to the GT system 102 (FIG. 1) and configured to deliver steam, for example, to the ST system 110 (FIG. 1) and / or heated water to other parts of the CCPP 100 (FIG. 1). As shown, the heat exchanger 108 includes a heat-insulating casing 140 (hereinafter, “casing 140”) configured to contain a fluid 142. The casing 140 can be housed in the HRSG enclosure 148. The casing 140 may include any presently known or later-developed heat-insulating duct configured to contain the fluid 142, for example, with an inner liner of carbon steel or stainless steel, a heat-insulating layer, and an outer carbon steel layer.

[0027] The fluid 142 can be any form of gas having a heat difference with the fluid 144 (shown only by the arrow) passing through a plurality of heat exchange tubes 146 of the heat exchanger 108. Heat is exchanged between the fluid 142 and the fluid 144. The fluid 142 can be combustion gas exhaust from the GT system 102 (FIG. 1), and the fluid 144 can be a liquid, for example, water, and / or a gas, for example, steam. The fluid 142 passes around the outside of the plurality of heat exchange tubes 146 and exits the casing 140 via an exhaust system 150, for example, a stack and / or a scrubber, etc., while the fluid 144 passes through the interior of the plurality of heat exchange tubes 146. The enclosure 148 can include any presently known or later-developed structural protection, for example, a building or other physical protection.

[0028] Figures 2 and 3 differ in that in FIG. 2, the tubes 146 extend in a vertical or vertical arrangement and the fluid 142 passes generally horizontally around them, whereas in FIG. 3, the tubes 146 extend in a horizontal or horizontal arrangement and the fluid 142 passes generally vertically around them. As used herein, “generally” when applied to the flow direction of the fluid 142 indicates that the fluid, when passing over or around the tubes 146 that may impede its path, typically proceeds in the specified direction with some or temporary deviation.

[0029] The tube 146 can have any currently known or later-developed form of heat exchange tube and can be made of any material capable of providing the desired heat transfer characteristics, flexibility, and ability to withstand the exposed environment. The tube 146 can vary in size depending on the application. For example, in some applications, the outer diameter can vary from 1.25 inches to 2.0 inches. In one embodiment, the tube 146 can take any form described in co-pending U.S. Patent Application No. 16 / 230,736, filed on December 14, 2018, which is incorporated herein by reference.

[0030] FIG. 4 shows a perspective view of one embodiment of a finned tube from the foregoing application. As shown, the tube 146 can include a plurality of disks 152 disposed around a central tube 154 aligned in the longitudinal direction 156. Each disk 152 can be substantially planar and can be stacked so as to be longitudinally disposed above and / or below at least one adjacent disk 152. The central tube 154 can include any currently known or later-developed tubular member configured to allow fluid 144 to pass through, for example, by pumping or other forces. Each disk 152 can include a plurality of fin segments 158 extending radially outward from a disk central portion 160, and thus the fin segments 158 extend outward from the central tube 154. The disk central portion 160 extends circumferentially around the outer periphery of the central tube 154. Each of the fin segments 158 is separated from an adjacent fin segment 158 by a serration 163. The fin segments 158 of adjacent disks can be aligned or offset in the circumferential and / or longitudinal directions. The fin segments 158 can be arranged in a helical configuration, an alternating pattern, and / or a random configuration with respect to one another longitudinally above and / or below them.

[0031] The disk 152 can be at least partially composed of aluminum and / or other thermally conductive materials such as beryllium, copper, gold, magnesium, iridium, molybdenum, rhodium, silver, tungsten, and / or other suitable materials, as well as alloys thereof. The central tube 154 can be at least partially composed of carbon steel, alloy steel, stainless steel, ferritic stainless steel, austenitic stainless steel, and / or other materials having sufficient thermal conductivity, stress resistance, and heat resistance.

[0032] In some embodiments, the HRSG may include the central tube 154 within a superheater and / or an evaporation section (not labeled) composed of materials resistant to high temperatures (e.g., 1100°F). The HRSG may also include the central tube 154 within an economizer and / or an evaporation section (not labeled) composed of materials having lower heat resistance and higher thermal conductivity. Although an example of the tube 146 has been described, it is understood that the heat exchanger tubes can take various alternative forms.

[0033] Figures 5 and 7 show schematic front views of a plurality of heat exchange tubes 146 (hereinafter, one or more "tubes" 146), and Figures 6 and 8 show schematic plan views of the tubes 146. Figures 5 - 8 have tubes 146 arranged vertically as in the embodiment of Figure 2. Figures 5 and 6 show tubes 146 in a row or aligned arrangement, and Figures 7 and 8 show tubes 146 in a non-aligned or staggered arrangement. As used herein, when applied to the tube 146, the term "aligned" or "aligned position" indicates that the rows 180 of adjacent tubes are in a row with respect to the flow direction of the fluid 142 through the heat exchanger 108. That is, the centers of the tubes 146 in all rows are on the same line or approximately on the same line, whereby the fluid 142 can flow through the tubes following the first row it encounters, and there is little or no flow affecting the portions of the tubes in subsequent rows. The aligned arrangement forms a linear flow path 196 (Figure 6).

[0034] In contrast, the term "misaligned" or "misaligned position" indicates that the rows 180 of adjacent tubes are not in a row with respect to the flow direction of the fluid 142. That is, the centers of the tubes 146 in different rows are not closely adjacent on the same line, whereby the fluid 142 affects at least a part of the tubes in the first row it encounters and at least a part of the tubes in most, if not all, subsequent rows. The misaligned arrangement forms a curved flow path 198 (FIG. 8). The extent to which the fluid 142 affects each row of tubes in the misaligned position depends on the degree of misalignment or stagger, that is, there are a number of misaligned positions.

[0035] Each tube 146 is positioned within the casing 140 and fixedly positioned at its opposite ends 162 and 164. The ends 162, 164 of the tube can have different structures. In one embodiment, each tube 146 can be fluidly coupled to headers 166, 170 at its ends 162, 164. Although not shown, it is understood that the various headers 166, 170 supplying a number of tubes 146 can each be coupled to a larger manifold. In the examples of FIGS. 5 and 7, the upper end 162 is coupled to the header 166. The other end 164 of each tube 146 can include a U-turn 168 that redirects the fluid 144 in the opposite direction or can be fluidly coupled to another header 170. The headers 166, 170 can fluidly couple the various tubes 146 and can allow the fluid 144 to enter and exit the heat exchanger 108. The tubes 146 can be supported by a support 172 in any currently known or later developed manner, as further described. In FIGS. 5 and 7, examples of the support 172 (partially shown in phantom lines) can include lugs attached to the header 166, lugs attached to a manifold (not shown) above the header 166, and / or supports on a floor 174 extending through the casing 140. The tubes 146 and the headers 166, 170 can be joined in any known manner, such as by welding, fasteners, etc.

[0036] As shown in the plan views of FIGS. 6 and 8, the tube 146 is arranged in any number of tube rows 180. FIG. 6 is taken along the line of sight A-A of FIG. 5, and FIG. 8 is taken along the line of sight B-B of FIG. 7. The line of sight A-A or B-B can be at one or more locations along the length of the tube 146 and at a sufficient distance from the fixed ends 162, 164 of the tube, but the tube can move despite those fixed ends. For purposes of illustration, three tube rows 180A, 180B, 180C are shown, but any number of rows may be used as observed in FIGS. 2-3. As described, one or more of the tube rows 180B are movable.

[0037] The heat exchanger 108 may include, for example, a fixed mount 182 that fixedly positions the tube rows 180A, 180C relative to the casing 140. (Hereinafter, the tubes are collectively referred to by reference numeral 146, the movable tubes are referred to as 146M, and the fixed tubes are referred to as 146F). The fixed mount 182 may include any structure capable of fixing the position of the tubes 146F in the fixed rows 180A, 180C of tubes. In the example shown, the fixed mount 182 includes an attachment member 184 that includes a sheet 186 for each heat exchange tube 146F in the fixed rows 180A, 180C of tubes. The attachment member 184 is fixed to the casing 140, for example, by fasteners, welding, etc.

[0038] The heat exchanger 108 also includes a movable mount 190 operatively coupled to each movable row 180B of tubes. The movable mount 190 includes a second attachment member 192 that includes a sheet 194 for each heat exchange tube 146M in the movable row 180B of tubes. In contrast to the fixed mount 182, the movable mount 190 is movable between two or more positions. As shown in FIG. 6, in the first alignment position, the heat exchange tubes 146M in the tube row 180B can be aligned with the heat exchange tubes 146F in the fixed tube rows 180A, 180C. As shown in FIG. 6, the alignment position forms a linear flow path 196 for the fluid 142 through the plurality of heat exchange tubes 146.

[0039] As shown in FIG. 8, due to the second misaligned position, the heat exchange tubes 146M in the movable row 180B of tubes cannot be aligned with the heat exchange tubes 146F in the tube rows 180A, 180C. As shown in FIG. 8, the misaligned or staggered positions form a curved flow path 198 for the fluid 142 passing through the heat exchange tubes 146.

[0040] As can be observed by comparing FIGS. 6 and 8, the attachment member 192 of the movable mount 190 is movable relative to the casing 140 (FIGS. 2-3), moving the tube row 180B between positions, i.e., the movable attachment member 192 and the tube row 180B are both movable. In FIG. 8, the attachment member 192 is, for example, in an offset position to the right, and in FIG. 6, the attachment member 192 is slid to one side, for example, to the left as indicated by arrow C. The movable mount 190 (attachment member 192) and / or the casing 140 may include any form of bearing necessary to enable movement.

[0041] Although one movable mount 190 is shown, any number of movable mounts 190 may be used between the fixed opposing ends 162, 164 of the tubes 146. That is, any number of movable mounts 190 can be used to move the tube row 180B between the aligned position (FIGS. 5 and 6) and the misaligned position (FIGS. 7 and 8) at one or more locations between the opposing ends 162, 164 of the tubes 146M in the tube row 180B. The movable mount 190 can move the tube row 180B from the aligned position to any misaligned position and from any misaligned position to the aligned position. The tubes 146 provide sufficient flexibility to allow movement along their lengths.

[0042] In one embodiment, the movable mount 190 can be manually moved between an aligned position and a misaligned position. In another embodiment, the heat exchanger 108 can also include an actuator 200 operably coupled to the movable mount 190 to move the tube row 180B between an aligned position (Figs. 5 and 6) and a misaligned position (Figs. 7 and 8). The actuator 200 can include any currently known or later developed controllable linear actuator, such as an electric motor, a hydraulic ram, a pneumatic ram, etc. Any form of transmission may also be used. Any number of actuators 200 can be used with any respective number of movable tube rows 180B. The movable tube rows 180B can also share an actuator 200.

[0043] In some embodiments, a control system 138 can be provided to operate the actuator 200. The control system 138 can be configured to operate the actuator 200 to move the tube row 180B between an aligned position and a misaligned position. In the example of the CCPP 100, the control system 138 can move the tube row 180B based on at least one operating parameter of the heat exchanger 108, the GT system 102 (Fig. 1), and / or the ST system 110 (Fig. 1), or any other machine to which the heat exchanger is operably coupled, via the actuator 200. It is understood that in other applications of the heat exchanger 108, the operating parameters can vary depending on the machine to which the heat exchanger is operably coupled.

[0044] In the example of the CCPP100, in the case of the GT system 102 (FIG. 1), the operating parameters may include, but are not limited to, exhaust temperature, volume, enthalpy, pressure, flow rate, GT exhaust velocity and Strouhal number, the load of the GT system, ambient temperature, degradation of the GT system, modification / upgrade of the GT system, and the deviation between the expected operation and the actual operation. In the case of the heat exchanger 108, the operating parameters may include, but are not limited to, heat transfer amount, duct burner load, steam or water temperature, flow rate, and resonance frequency adjustment. In the case of the ST system 110 (FIG. 1), the operating parameters may include, but are not limited to, steam temperature, volume, enthalpy, pressure, and flow rate.

[0045] Referring again to FIG. 3, in another embodiment, the tube 146 is arranged in a horizontal arrangement, and the fluid 142 passes generally vertically through the horizontal arrangement. That is, the plurality of heat exchange tubes 146 are arranged to extend substantially horizontally within the casing 140, and the fluid 142, for example, GT exhaust, flows generally in the vertical direction. The opposing ends 262, 264 (FIG. 3) of the tube 146 are arranged in the same manner as shown in FIGS. 5 and 7, that is, the header 166 is provided at the opposing ends 262, 264 of the tube 146 that are horizontally separated.

[0046] FIGS. 9 and 10 show cross-sectional side views of the heat exchange tube 146 and the fixed mount and movable mount according to an embodiment of the present disclosure applicable to the arrangement of FIG. 3. Here, the heat exchanger 108 includes a fixed mount 282. The fixed mount 282 is fixedly coupled to the support 172, for example, by fasteners and / or welding, and supports the weight of the tube 146. The fixed mount 282 includes a first opening 204 for each respective heat exchange tube 146F in the fixed rows 180A, 180C of the tubes. Each first opening 204 is configured to position the respective tube 146F in a fixed position. For example, each first opening 204 has an inner diameter sized to allow thermal expansion but not to permit other movement of the tube 146F therein.

[0047] The fixed mount 282 also includes a second opening 206 for each respective tube 146M in the movable row 180B of tubes. The lines of the second openings 206 can be provided for the tubes 146M in the movable row 180B of tubes. Each second opening 206 is configured to allow movement of the respective heat exchange tube 146M between an aligned position as shown in FIG. 9 and a misaligned position as shown in FIG. 10. For example, the second opening 206 is configured with a first range 208 configured to position the respective heat exchange tubes 146M of the movable row 180B of tubes in an aligned position, as best shown in FIG. 9, and a second adjacent range 210 configured to position the respective heat exchange tubes 146M in a misaligned position, as best shown in FIG. 10. Each second opening 206 has a vertical dimension sized to allow thermal expansion but not to permit other vertical movement of the tube 146M therein. The adjacent ranges 208, 210 allow lateral, horizontal movement of the movable tube 146M.

[0048] The heat exchanger 108 also includes a movable mount 290 operably coupled to each heat exchange tube 146M of the movable row 180B of tubes and configured to move the row of tubes within the second opening 206 between an aligned position and a misaligned position. The movable mount 290 is separated from the fixed mount 282 and can move independently of the fixed mount 282. The distance between the movable mount 290 and each respective fixed mount 282, and the number of movable mounts 290 suitable to achieve the desired movement, can vary depending on, for example, the number of tubes, the size and / or length of the tubes, and the specific dimensions of the other heat exchanger components.

[0049] The movable mount 290 includes an attachment member 292 that includes a sheet 294 for each heat exchange tube 146M of the second row 180B of tubes. In contrast to the fixed mount 282, the movable mount 290 is movable between an aligned position in which the heat exchange tubes 146M in the movable row 180B of tubes are aligned with the heat exchange tubes 146F in the fixed rows 180A, 180C of tubes, as shown in FIG. 9, and a misaligned position (in a staggered pattern) in which the heat exchange tubes 146M in the movable row 180B of tubes are not aligned with the heat exchange tubes 146F in the fixed rows 180A, 180C of tubes, as shown in FIG. 10.

[0050] As shown in FIG. 9, the first alignment position forms a linear flow path 196 for the fluid 142 passing through the plurality of heat exchange tubes 146. In contrast, as shown in FIG. 10, the second misaligned or staggered position forms a curved flow path 198 for the fluid 142 passing through the heat exchange tubes 146. As observed by comparing FIGS. 9 and 10, the attachment member 292 of the movable mount 290 is movable relative to the casing 140 (FIGS. 2-3) and moves the tube row 180B between the alignment position and the misaligned position. In FIG. 9, the attachment member 292 is, for example, in an offset position to the left, and the tube 146M is within the range 208 of the second opening 206 in the fixed mount 282. And in FIG. 10, the attachment member 292 is slid to one side, for example, to the left as indicated by arrow C, and is present at a position where the tube 146M is within the adjacent range 210 of the second opening 206 of the fixed mount 282. The movable mount 290 (attachment member 292) and the support 172 can include any form of bearing suitable to enable the desired movement.

[0051] Although one movable mount 290 is shown, any number of movable mounts 290 may be used between the fixed opposing ends 162, 164 (FIG. 3) of the tubes 146. That is, any number of movable mounts 290 can be used to move the tube row 180B between the first alignment position (FIG. 9) and the second misaligned position (FIG. 10) at one or more locations between the opposing ends of the tubes 146M in the tube row 180B. The movable mount 290 can move the tube row 180B from the alignment position to the misaligned position, from the misaligned position to the alignment position, and to any location between the two positions.

[0052] In one embodiment, the movable mount 290 can be manually moved between positions. In another embodiment, the heat exchanger 108 can also include an actuator 200 operably coupled to the movable mount 290 to move the tube row 180B between an aligned position (FIG. 9) and a misaligned position (FIG. 10). The actuator 200 can include any currently known or later developed controllable linear actuator, such as an electric motor, a hydraulic ram, a pneumatic ram, etc. Any form of transmission may also be used. Any number of actuators 200 can be used with any respective number of movable tube rows 180B. In some embodiments, a control system 138 can be provided to operate the actuator 200. As previously described herein, the control system 138 can be configured to operate the actuator 200 to move the tube row 180B between positions based on at least one operating parameter of the heat exchanger 108, the GT system 102 (FIG. 1), and / or the ST system 110 (FIG. 1), and / or any other machine to which the heat exchanger is operably coupled.

[0053] FIGS. 6, 8, 9, and 10 show an alternating arrangement of fixed tubes 146F and movable tubes 146M, with the row 180B of movable tubes following the row 180A of fixed tubes, but it should be noted that such a pattern is not necessary. Rather, different numbers of fixed rows 180A, 180C and different numbers of movable rows 180B can be used in various combinations to achieve the desired flow paths 196, 198.

[0054] Embodiments of the present disclosure may also include a method for operating the HRSG of the CCPP100 (FIG. 1). It will be understood that the method may be executed by the CCPP control system 138 (FIG. 1). The HRSG may include a heat exchanger 108 including a plurality of heat exchange tubes 146 disposed in tube rows 180A, 180B, 180C as described herein. During operation, at least one operating parameter of the HRSG, the GT system 102 (FIG. 1) of the CCPP100 (FIG. 1), and / or the ST system 110 (FIG. 1) of the CCPP100 (FIG. 1) is measured. Each operating parameter may be any of the aforementioned parameters and may be measured in any suitable manner, such as by a sensor, gauge, etc., and digitally communicated to the control system 138 (FIG. 1).

[0055] The control system 138 can determine, for example, by comparing the measured value with a threshold, whether at least one operating parameter fails to meet the threshold. In response to at least one operating parameter that does not meet the threshold, the control system 138 (FIG. 1) can move the tube row 180B relative to the tube rows 180A, 180C. In one example, the control system 138 can actuate the actuator 200 and move the tube row 180B between an aligned position and a misaligned position based on at least one operating parameter that does not meet the threshold, as described herein. This process can be repeated to determine whether / how the change in the tube position affected the operating parameter.

[0056] The positioning of the adjustable heat exchange tubes according to embodiments of the present disclosure provides a number of advantages. By adjustment, the heat exchanger can be adjusted, for example, for the heat input variation of the exhaust from the GT system to the HRSG. The heat exchanger enables the control of the steam temperature, that is, it facilitates better control of the startup of the ST system in the CCPP arrangement compared to the output control of a complex GT system. For example, during the startup of the ST system, placing the tubes of the superheater and reheater of the HRSG in the aligned position generates low-temperature steam, and gradually moving to the misaligned position causes the steam temperature to gradually rise. The CCPP efficiency can also be improved when heat transfer reduction is required (in the aligned arrangement) due to a decrease in the spray water of the superheat reducer and a reduction in the draft loss of the HRSG. Using a staggered arrangement can result in, for example, an increase in heat transfer, an increase in draft loss, an increase in steam temperature in the superheater and reheater, an increase in the generated steam in the evaporator, and an increase in the water temperature in the economizer.

[0057] The tube 146M within the heat exchanger 108 can be adjusted to provide better access to a cleaning tool (such as a brush, power washer, etc.) by opening a linear path through a row of tubes in the aligned position or another path through a row of tubes in the misaligned position, such as a diagonal. The different positions enable deeper access to different rows of tubes.

[0058] Furthermore, during the operation of the heat exchanger 108, the positioning of the heat exchange tubes can be adjusted to address unexpected noise caused by resonance of the vortex shedding frequency. For example, for a given heat input to the HRSG, the exhaust velocity of the GT and the Strouhal number (i.e., a dimensionless number representing the mechanism of the oscillating flow) can be varied by adjusting the tube arrangement, eliminating the resonance of the vortex shedding frequency, and in some cases eliminating the need for a baffle to address the problem.

[0059] As used throughout this specification and the claims, the language representing approximation can be applied to modify any quantitative expression that can vary within a reasonable range without causing a change in the relevant basic function. Thus, values modified by terms such as "about," "approximately," and "substantially" are not limited to the precisely stated value. In at least some instances, the language representing approximation can correspond to the accuracy of the equipment used to measure the value. Here, as well as throughout this specification and the claims, limitations of a range are combinable and / or replaceable, and such ranges are identified and include all sub-ranges subsumed therein, unless the context and language specifically dictate otherwise. "About" applied to a particular value of a range applies to both values and can indicate + / - 10% of the stated value, unless specifically dependent on the accuracy of the equipment used to measure the value.

[0060] All corresponding structures, materials, acts, and equivalents of means-plus-function or step-plus-function elements in the following claims are intended to include any structure, material, or act for performing the recited 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 and is not intended to be exhaustive or to limit the disclosure to the forms 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 present disclosure. The embodiments were chosen and described in order to best explain the principles of the disclosure and its practical application and to enable others of ordinary skill in the art to understand the disclosure in various embodiments with various modifications as are suited to the particular use contemplated.

Description of Reference Numerals

[0061] 100 Combined Cycle Power Plant (CCPP) 102 Gas Turbine (GT) System 104 Generator 106 Shaft 108 Heat Exchanger 110 Steam Turbine (ST) System 112 Generator 120 Compressor 124 Combustor 126 Combustion region 128 Fuel nozzle assembly 130 Gas turbine 132 High pressure (HP) turbine 134 Intermediate pressure (IP) turbine 136 Low pressure (LP) turbine 138 CCPP control system 140 Casing 142 Fluid 144 Fluid 146 Heat exchange tube 146F Fixed heat exchange tube 146M Movable heat exchange tube 148 HRSG enclosure 150 Exhaust system 152 Disk 154 Central tube 156 Longitudinal direction 158 Fin segment 160 Disk central portion 162 End 163 Serration 164 End 166 Header 168 U-turn 170 Header 172 Support 174 Floor 180 Tube row 180A Fixed tube row 180B Movable tube row 180C Fixed tube row 182 Fixed mount 184 Attachment member 186 Sheet 190 Movable mount 192 Attachment member 194 Sheet 196 Linear flow path 198 Curved flow path 200 Actuator 204 First opening 206 Second opening 208 First range 210 Second adjacent range 262 End 264 End 282 Fixed mount 290 Movable mount 292 Attachment member 294 Sheet A - A line of sight B - B line of sight C Arrow

Claims

1. A heat exchanger (108), wherein the heat exchanger (108) includes a casing (140) configured to allow a first fluid (142) to pass therethrough; a plurality of heat exchange tubes (146) fluidly coupled to headers (166, 170) and positioned within the casing (140), the plurality of heat exchange tubes (146) being arranged in a first row of tubes (180, 180A, 180B, 180C) and a second row of tubes (180, 180A, 180B, 180C); a fixed mount (182, 282) that fixedly positions the first row of tubes (180, 180A, 180B, 180C) relative to the casing (140); a movable mount (190, 290) operably coupled to the second row of tubes (180, 180A, 180B, 180C), the movable mount (190, 290) being movable between an aligned position where the heat exchange tubes (146) in the second row of tubes (180, 180A, 180B, 180C) are aligned with the heat exchange tubes (146) in the first row of tubes (180, 180A, 180B, 180C) to form a linear flow path (196) for the first fluid (142) passing through the plurality of heat exchange tubes (146) and a non-aligned position where the heat exchange tubes (146) in the second row of tubes (180, 180A, 180B, 180C) are not aligned with the heat exchange tubes (146) in the first row of tubes (180, 180A, 180B, 180C) to form a curved flow path (198) for the first fluid (142) passing through the plurality of heat exchange tubes (146); and heat is exchanged between the first fluid (142) passing through the plurality of heat exchange tubes (146) and a second fluid (144); the fixed mount (182, 282) A first opening (204) for each respective heat exchange tube (146) in the row of the first tubes (180, 180A, 180B, 180C), each first opening (204) being configured to position the respective first heat exchange tube (146) in a fixed position. A second opening (206) for each respective heat exchange tube (146) in the row of the second tubes (180, 180A, 180B, 180C), each second opening (206) being configured to enable movement of the respective heat exchange tube (146) between the aligned position and the misaligned position. Including The movable mount (190, 290) is operably coupled to each heat exchange tube (146) of the row of the second tubes (180, 180A, 180B, 180C), and moves the row of the second tubes (180, 180A, 180B, 180C) within the second opening (206) between the aligned position and the misaligned position, a heat exchanger (108). **Claim 2** Each of the plurality of heat exchange tubes (146) includes a central tube (154) and a plurality of disks (152) extending outwardly from the central tube (154), the heat exchanger (108) according to claim 1. **Claim 3** Each second opening (206) has a first range (208) configured to position the respective heat exchange tube (146) of the row of the second tubes (180, 180A, 180B, 180C) in the aligned position, and an adjacent second range (210) configured to position the respective heat exchange tube (146) of the row of the second tubes (180, 180A, 180B, 180C) in the misaligned position, the heat exchanger (108) according to claim 1. **Claim 4** The plurality of heat exchange tubes (146) are arranged to extend substantially horizontally within the casing (140), and the first fluid (142) flows generally in a vertical direction, the heat exchanger (108) according to claim 1. **Claim 5** The fixed mounts (182, 282) are first mounting members (184, 192, 292) that include sheets (186, 194, 294) for each heat exchange tube (146) of the first row of tubes (180, 180A, 180B, 180C), and the first mounting members (184, 192, 292) include first mounting members (184, 192, 292) fixed to the casing (140). The movable mounts (190, 290) are second mounting members (192) that include sheets (186, 194, 294) for each heat exchange tube (146) of the second row of tubes (180, 180A, 180B, 180C), the second mounting members (192) are movable relative to the casing (140), and the heat exchanger (108) according to claim 1, wherein the second mounting members (192) include second mounting members (192) that move the second row of tubes (180, 180A, 180B, 180C) between the aligned position and the misaligned position.

6. The heat exchanger (108) according to claim 5, wherein the plurality of heat exchange tubes (146) are arranged to extend substantially vertically within the casing (140), and the first fluid (142) flows generally horizontally.

7. Each of the plurality of heat exchange tubes (146) is fixed to its opposing ends (262, 264), and the movable mounts (190, 290) move the second row of tubes (180, 180A, 180B, 180C) between the aligned position and the misaligned position at a location between the opposing ends (262, 264) of the heat exchange tubes (146) in the second row of tubes (180, 180A, 180B, 180C). The heat exchanger (108) according to claim 1.

8. The heat exchanger (108) according to claim 1, further comprising an actuator (200) operably coupled to the movable mounts (190, 290) to move the second row of tubes (180, 180A, 180B, 180C) between the aligned position and the misaligned position.

9. The heat exchanger (108) according to claim 8, further comprising a control system (138) configured to operate the actuator (200) and move the second tube row (180, 180A, 180B, 180C) between the aligned position and the misaligned position based on at least one operating parameter of at least one of the heat exchanger (108) and a machine to which the heat exchanger (108) is operatively coupled).

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