System for reheating steam temperature down-regulation control in heat recovery steam generator

Abstract

A heat recovery steam generator (HRSG) is disclosed. The HRSG includes: a high temperature section including a first reheater coupled with at least one high pressure superheater in a parallel orientation, the first reheater separated from the at least one superheater by at least one barrier wall; an evaporator coupled downstream of the high temperature section, the evaporator configured to extract heat from the gas exiting the high temperature section; and a damper system upstream of the evaporator, the damper system configured to divert gases exiting from an outlet of the first reheater and an outlet of the at least one superheater.

Description

BACKGROUND OF THE DISCLOSURE

[0001] The field of the present disclosure generally relates to heat recovery steam generators for gas turbine engine exhaust. More specifically, the present disclosure relates to systems for implementing steam temperature reduction control in a heat recovery steam generator.

[0002] In various industries, heat exchangers are used to transfer heat from one medium to another. A heat recovery steam generator (HRSG) is an example of a heat exchanger that can be used in combined cycle power plants and similar facilities to generate steam and additional power from exhaust gases. The HRSG can use gas turbine engine exhaust to heat a fluid flowing through a heat exchanger in the HRSG, such as, for example, to convert water into steam for supply to a steam turbine. In some configurations, the fluid can be steam generated at multiple pressure levels and conducted to any of the high-pressure, medium-pressure, and / or low-pressure sections of the steam turbine. HRSGs typically include spray desuperheaters (desuperheaters) to reduce the temperature of the high pressure and reheat the outlet steam by combining the superheated steam with water such that the steam is cooled as the water evaporates.

[0003] Some combined cycle systems are configured with steam turbine extractions to provide process steam to support industrial, carbon capture, or district heating systems. These steam extractions are typically pressure controlled to maintain the process steam supply pressure over a steam flow or facility load operating range. If the facility load or process steam demand exceeds the allowable operating range for extracting steam from the turbine, there are typically measures to extract steam from a high-pressure steam source and subsequent pressure and temperature reduction to meet the process requirements. This fallback mode is much less efficient because the process steam no longer expands first to do work in the steam turbine. Operation is most efficient when the process steam is available from steam extraction because it has already done work while expanding to the (lower) pressure required for the process. The minimum steam turbine load at which process steam extraction is technically feasible is limited because as the load decreases, the extraction steam temperature gradually increases until the steam turbine components at the extraction point become overheated. This occurs due to a decrease in the pressure ratio of steam expansion across the turbine between the steam inlet (whose pressure decreases as the flow rate decreases) and the steam extraction (which is controlled to a fixed pressure by a valve, as required for supply to a process steam user). The ideal location for steam extraction is often downstream of the medium-pressure (IP) turbine inlet. This results in a need for medium-pressure (IP) turbine inlet (reheat) steam temperature reduction control to manage the temperature of the steam exiting the steam turbine extraction. However, reheat steam temperature control using conventional steam temperature control means may be limited. Expanding the operation of steam extraction activities is desirable because it is more efficient than diverting the process steam supply to a higher pressure and temperature source since such steam no longer has the opportunity to do work by first expanding through the steam turbine.

[0004] A conventional reheater steam temperature control system with water spray attemperation between the reheater sections is limited by the amount of water that can be safely injected and vaporized within the HRSG. This is also inherently inefficient as a high level of energy is used to vaporize the water spray within the HRSG. A more efficient approach is to use cold steam instead of water to reduce the temperature of the steam entering the reheater. However, this approach is also limited in terms of temperature control authority by how much the outlet steam temperature can be reduced.

[0005] Accordingly, there is a need in the art for improved control of the reduction of reheater steam temperature in a heat recovery steam generator system. SUMMARY OF THE INVENTION

[0006] In one embodiment, a heat recovery steam generator is provided. The heat recovery steam generator includes: a high temperature section including a first reheater coupled in a parallel orientation with at least one high pressure superheater, the first reheater being separated from the at least one superheater by at least one baffle wall; an evaporator coupled downstream of the high temperature section, the evaporator being configured to extract heat from the gas exiting the high temperature section; and a damper system upstream of the evaporator, the damper system being configured to redirect the gas exiting the outlet of the first reheater and the outlet of the at least one superheater.

[0007] In another aspect, a power generation system is provided. The power generation system includes: a gas turbine configured to generate electricity and discharge exhaust gas through an exhaust port; and a heat recovery steam generator having a gas inlet in communication with the exhaust port of the gas turbine. The heat recovery steam generator includes: a high temperature section including a first reheater coupled in a parallel orientation with at least one high pressure superheater, the first reheater being separated from the at least one superheater by at least one baffle wall; an evaporator coupled downstream of the high temperature section, the evaporator being configured to extract heat from the gas exiting the high temperature section; and a damper system upstream of the evaporator, the damper system being configured to redirect the gas exiting the outlet of the first reheater and the outlet of the at least one superheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic view of a high temperature element of an exemplary prior art power generation system;

[0009] Figure 2 is a schematic view of an exemplary heat recovery steam generator including a damper system, the exemplary heat recovery steam generator being an improvement over the Figure 1 power generation system shown;

[0010] Figure 3A is a schematic view of the Figure 2 damper system in an open state;

[0011] Figure 3B is in a closed state Figure 2 schematic diagram of the damper system;

[0012] Figure 4 is a schematic diagram of an alternative heat recovery steam generator including a damper system; and,

[0013] Figure 5 is a schematic diagram of an alternative heat recovery steam generator including a damper system.

[0014] The reference numerals used in the drawings and their meanings are listed in a reference numeral list in a general form. In principle, the same components have the same reference numerals in the drawings. Detailed Description

[0015] In the following specification and claims, a number of terms will be used which are to be defined as having the following meanings.

[0016] As used herein, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" include plural references. The terms "comprising", "including", and "having" are intended to be inclusive and mean that there may be additional elements in addition to the listed elements. The term "optional" or "optionally" means that the subsequent described event or circumstance may or may not occur, and the description includes instances where the event occurs and instances where the event does not occur.

[0017] Unless otherwise indicated, approximate language, such as "substantially", "essentially", and "about", as used herein, indicates that, as would be recognized by one of ordinary skill in the art, the so-modified term may apply only to an approximate degree, and not an absolute or perfect degree. Thus, a value modified by one or more terms, such as "about", "approximately", and "substantially", is not limited to the specified exact value. In at least some instances, the approximate language may correspond to the precision of the instrument used to measure the value. Range limitations may be identified herein as well as throughout the specification and claims. Unless the context or language indicates otherwise, these ranges may be combined and / or interchanged and include all subranges subsumed therein.

[0018] In addition, unless otherwise indicated, the terms "first", "second", etc. are used herein only as labels and are not intended to impose an order, position, or hierarchical requirement on the items to which these terms refer. Further, for example, a reference to 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.

[0019] Embodiments of the present disclosure relate to a heat recovery steam generator (HRSG) system that utilizes gas to expand control authority and maintain the efficiency of steam temperature control. The systems described herein include an evaporator, a reheater, and a superheater. The system also includes a damper system or an air diversion system to redirect, reduce, or divert the airflow to the reheater, thereby facilitating a reduction in the reheated steam temperature leaving the HRSG.

[0020] Figure 1 is a block diagram of the high-temperature portion of an exemplary power generation system 10 that includes a gas turbine 20, an HRSG 100, a high-pressure steam turbine 165, and an intermediate-temperature steam turbine 175. Note that the elements shown and labeled in the HRSG 100 are only the frontmost sections of interest in the present disclosure. The HRSG 100 includes an inlet section 102 and an outlet interface 104 that directs the warm gas 40 into downstream components of the HRSG 100, which include economizers, evaporators, and superheaters for HP, IP, and typically LP steam generation modules (not shown). In some embodiments, the HRSG 100 also includes a downstream emission reduction catalyst (not shown).

[0021] The HRSG 100 receives hot exhaust gas 30 from the gas turbine 20, and this hot exhaust gas flows through a high-pressure superheater and reheater section (referred to as the high-temperature section 110) and an evaporator 150. The HRSG 100 is an indirect heat exchanger where water or steam is provided to the evaporator 150 of the HRSG 100 to enable heat extraction from the hot exhaust gas 30 within the HRSG 100.

[0022] The high-temperature section 110 includes a configuration of a reheater 130 and a high-temperature superheater 120 that are typically arranged in series. As the exhaust gas 30 passes through the HRSG 100, the high-pressure (HP) steam generated in the evaporator 150 is superheated by the exhaust gas, and this high-pressure (HP) steam cools the exhaust gas 30 as the exhaust gas provides heat to the steam. The superheater 120 may include a steam outlet 128, where the HP steam supply leaving the superheater 120 is connected to the HP steam turbine 165 at the steam outlet 128 of the superheater 120. The HP steam turbine expands the steam to an intermediate pressure (IP) for reheating before entering the IP steam turbine 175. The reheater 130 includes a steam outlet 138 that supplies the IP steam turbine 175. Additional IP steam 131 may be added to the HP turbine exhaust steam leaving the HP steam turbine 165 and entering the reheater 130. The HP steam temperature at the steam outlet 128 of the superheater 120 and the IP steam temperature at the steam outlet 138 of the reheater 130 are each controlled by injecting water into the steam at a desuperheater (126 or 136), respectively. The steam at the steam outlet 184 leaving the IP turbine 175 proceeds to a low-pressure turbine and / or process users (not shown).

[0023] The evaporator 150 is downstream of the high-temperature section 110 and extracts heat from the exhaust gas 30 leaving the high-temperature section 110. The evaporator 150 includes a series of fluid tubes (not shown) that extract heat from the exhaust gas 30 leaving the high-temperature section 110. The fluid tubes of the evaporator 150 are connected by a fluid conduit 152 to an HP feedwater system (not shown) and are connected by an economizer section (not shown) to a feed pump system (not shown) that circulates fluid within the system. As the exhaust gas 30 flows through the evaporator 150 and downstream HP economizer, IP, and possibly LP steam generation loops, the exhaust gas is further cooled before being discharged to a chimney or a downstream process such as a carbon capture system (CCS).

[0024] Figure 2 is a schematic diagram of an exemplary embodiment of the high-temperature portion of the HRSG 100. In this exemplary embodiment, the HRSG 100 includes a high-temperature section 110 and an evaporator 150 downstream of the high-temperature section 110. The HRSG 100 has an enclosure wall 106 that defines a heating gas duct through which the exhaust gas 30 from the gas turbine 20 flows (in the direction shown by the arrow 30).

[0025] In this exemplary embodiment, the high-temperature section 110 includes at least two high-pressure superheaters 120 connected in a parallel orientation to at least one reheater 130. Each of the superheaters 120 includes an inlet 122 and an outlet 124, and the reheater 130 includes an inlet 132 and an outlet 134. As used herein, the term "parallel" configuration refers to the arrangement of heat transfer sections where the superheaters 120 and the reheater 130 are adjacent to each other with respect to the gas flow passing through them, the inlets (122, 132) are upstream of the outlets (124, 134), and the inlets (122, 132) of the superheaters 120 and the reheater 130 are substantially aligned along a plane P. Each of the superheaters 120 and the reheater 130 is separated by a baffle wall 108 such that only the exhaust gas 30 can enter and leave the corresponding inlets (122, 132) and outlets (124, 134) of the superheaters 120 and the reheater 130. The baffle wall 108 separating the superheaters 120 and the reheater 130 is rated temperature and is selected based on the normal / operating gas temperature of the exhaust gas 30 cooled by steam. In some embodiments, the baffle wall 108 is rated at approximately 900 degrees Fahrenheit to approximately 1300 degrees Fahrenheit.

[0026] In some embodiments, the high-temperature section 110 includes a plurality of high-pressure superheaters 120 and a plurality of reheaters 130 connected in a parallel configuration such that each reheater 130 is located between the plurality of superheaters 120, and the plurality of superheaters 120 are separated from the reheater 130 by a baffle wall 108.

[0027] The evaporator 150 is located downstream of the high-temperature section 110 to extract additional heat from the exhaust gas 32 leaving the high-temperature section 110 (as Figure 3A and Figure 3B indicated by the dashed arrows in). In some embodiments, the evaporator 150 is a once-through high-pressure evaporator through which feed water from a fluid conduit 152 of an HP feed water system (not shown) is directed.

[0028] In an exemplary embodiment, a damper system 160 is used to control the steam temperature. The damper system 160 is located downstream of the high-temperature section 110 (superheater 120 and reheater 130) such that the gas leaving the outlets (124, 134) of the superheater 120 and reheater 130 is directed through the damper system 160. Thus, in the exemplary embodiment, the damper system 160 is located between the high-temperature section 110 and the evaporator 150 so that the exhaust gas leaving the outlets (124, 134) of the superheater 120 and reheater 130 can be diverted. In addition, the damper system 160 enables the reduction of the reheated steam temperature and the regulation of the reheated steam temperature leaving the high-temperature section 110 in order to keep the steam turbine extraction temperature at the steam turbine outlet 184 within the material limits of the components within the power generation system 10 in the case of effective steam turbine extraction under pressure control.

[0029] The damper system 160 includes independently controlled dampers that are selectively movable at the outlets (124, 134) of the superheater 120 and reheater 130. In other words, the superheater 120 is located upstream of the superheater damper 162, and the reheater 130 is located upstream of the reheater damper 163. The dampers (162, 163) can be independently and selectively moved to a fully open position / state ( Figure 3A shown in), a fully closed position / state ( Figure 3B shown in), or an intermediate state positioned between the fully open and closed positions (hereinafter referred to as the "partially open position"). The adjustment of the reheater damper 163 between the fully open position and the fully closed position provides closed-loop temperature control of the reheated steam entering the IP steam turbine 175 over a very large operating range because in the fully closed position, no gas flows through the reheater 130, as Figure 3B shown. In a similar manner, the HP steam temperature can be controlled by adjusting a portion of the superheater damper 162 and / or coordinated with additional HP steam temperature control measures (not shown).

[0030] By way of example, in Figure 3AIn [this situation], all the air dampers (162, 163) are in the fully open position, and the gas (indicated by the vector showing the air flow pattern) continuously flows through the superheater 120 and the reheater 130. In some embodiments, the air dampers (162, 163) are louvers. In other embodiments, the air dampers (162, 163) are flap diverters. In other embodiments, the air dampers (162, 163) are diverter dampers. In some embodiments, the air dampers (162, 163) are series diverters. In some embodiments, the air dampers (162, 163) are butterfly dampers. In an alternative embodiment, any other type of air damper that enables the air damper system 160 to function as described herein can be used.

[0031] As Figure 3B shown, the reheater damper 163 is in the fully closed position, and the superheater damper 162 is in the fully open position. In this configuration, the reheater damper 163 diverts the gas towards the superheater 120 (indicated by the vector showing the air flow pattern). In some embodiments, the reheater damper 163 moves to a partially open position while the superheater damper 162 is in the fully open position, thereby creating a gas-side pressure difference between the reheater 130 and the superheater 120 and reducing the air flow to the reheater 130. This pressure difference causes an increase in the velocity of the gas directed to the superheater 120 when the gas is diverted from the reheater 130. This helps to improve heat transfer in the superheater 120. In some embodiments, the air damper system 160 includes only the reheater damper 163.

[0032] Figure 4 Shown is ( Figure 2 as shown in) an alternative embodiment air damper system 260 of the air damper system 160. In Figure 4 the exemplary embodiment of, the air damper system 260 includes a single reheater damper 263 located upstream of the inlet 132 of the reheater 130. The reheater damper 263 can be moved to the fully open position, the fully closed position, or any intermediate position (hereinafter referred to as "partially open position") between the fully open position and the fully closed position. Similar to Figure 2 the air damper system 160 of, the reheater damper 263 selectively reduces the exhaust air flow to the reheater 130, and the reheater damper 263 diverts the gas towards the superheater 120 (indicated by the vector showing the gas pattern) by selectively moving the reheater damper 263 to one of the fully open, fully closed, or partially open positions.

[0033] In some embodiments, the baffle wall 108 that separates the reheater 130 from the superheater 120 can be porous such that gas can partially enter the reheater 130. In some embodiments, one or both of the baffle walls 108 are formed with a gap (not shown) that enables gas to partially enter the reheater 130. The gap can extend along the entire length of one or both of the baffle walls 108 or can extend only partially along the length of the baffle wall 108 toward the outlets (124, 134) of the reheater 130 and the superheater 120. The partial or porous baffle wall 108 allows for limiting the maximum authority of reheated steam temperature control and also reduces the smoothness of the gas temperature profile entering the downstream evaporator 150. By way of example, the end 264 of one of the baffle walls 208 is at a distance D from the outlets (124, 134) such that gas is partially diverted from the superheater 120 adjacent the baffle wall 208. The baffle wall 208 is made of a material selected to be rated for and withstand the isothermal temperature difference. The damper system 260 effects a reduction in the reheated steam temperature and the regulation of the reheated steam temperature to maintain the steam turbine extraction temperature within the material limits of the components of the power generation system 10 in the case of an effective steam turbine extraction under pressure control.

[0034] Figure 5 A schematic illustration of an alternative embodiment of the HRSG 100 and the damper system 160 (shown in Figure 2 is presented. In an Figure 5 exemplary embodiment, the HRSG 300 includes a high temperature section 310 having a first reheater 330 and a second reheater 340 in a series configuration, and a superheater 320 arranged in a parallel configuration with the first reheater 330 and the second reheater 340, similar to those Figure 1 shown in. As used herein, the term series configuration refers to the arrangement of the reheaters (330, 340) where the outlet 334 of the first reheater 330 is in line and upstream of the inlet 342 of the adjacent second reheater 340.

[0035] The first reheater 330 and the second reheater 340 are separated by an embedded damper 360 that is used to facilitate control of the air flow between the first reheater 330 and the second reheater 340. In the exemplary embodiment, the damper 360 can be, but is not limited to, merely a louver, a flap deflector, and / or a butterfly damper. Alternatively, any other type of damper that enables the damper system to function as described herein can be used. Similar to the damper system 260 (as Figure 4As shown, the damper 360 can be selectively moved to a fully open position, a fully closed position, or any intermediate position (hereinafter referred to as "partially open position") between the fully open position and the fully closed position. The damper 360 selectively reduces the airflow between the first reheater 330 and the second reheater 340, and deflects the gas towards the superheater 320 due to the pressure difference between the parallelly arranged second reheater 340 and the superheater 320 (shown by the vectors indicating the airflow pattern). The baffle wall 308 separating the superheater 320 from the second reheater 340 is at the rated temperature and is selected based on the maximum temperature of the steam-cooled exhaust gas 30 seen at the damper 360 position. The damper 360 achieves a reduction and regulation of the reheated steam temperature leaving the high-temperature section 310 so as to keep the steam turbine extraction temperature within the material limits of the components within the power generation system 10 in the case of effective pressure-controlled steam turbine extraction.

[0036] The systems described herein facilitate a reduction or redirection of the airflow to the reheater, or directly control the gas temperature entering the reheater, resulting in a controlled reheated steam temperature leaving the high-temperature section of the HRSG. Specifically, the damper system regulates the hotter and colder gases leaving the high-temperature section while controlling the steam temperature leaving the reheater, such that the evaporator receives gases at substantially the same average temperature. Additionally, the damper system promotes enhanced operational flexibility and control of the superheater and reheater loads by deflecting the gas through selectively opened and closed dampers, without relying on desuperheaters to mix spray water or steam midway through the reheater and superheater. Neither spray water nor steam mixing for steam temperature control has the necessary control authority to substantially extend the steam extraction to low-load process operations in the case of effective pressure-controlled steam turbine extraction.

[0037] The methods, systems, and compositions disclosed herein are not limited to the specific embodiments described herein, but rather the steps of the methods, the elements of the systems, and / or the elements of the compositions can be used independently and separately from the other steps and / or elements described herein. For example, the methods, systems, and compositions are not limited to being practiced only with the rotating machines as described herein. Instead, the methods, systems, and compositions can be implemented and used in conjunction with many other applications.

[0038] Although the specific features of various embodiments may be shown in some figures and not in others, this is merely for convenience. Additionally, the reference to "one embodiment" in the above description is not intended to be construed as excluding the existence of additional embodiments that also incorporate the described features. Any feature of the figures can be referenced and / or claimed in combination with any feature of any other figure according to the principles of the present disclosure.

[0039] This written description uses examples, including the best mode, to enable any person skilled in the art to practice the present disclosure, including making and using any device or system and performing any combined method. The patentable scope of the present disclosure is defined by the claims and may include other examples that occur to those skilled in the art. If such other examples have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ materially from the literal language of the claims, then such other examples are intended to be within the scope of the claims.

[0040] Although the invention has been described in accordance with various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the claims.

[0041] Other aspects of the invention are provided by the subject matter of the following clauses:

[0042] A heat recovery steam generator, comprising: a high temperature section including a first reheater coupled to at least one high pressure superheater in a parallel orientation, the first reheater being separated from the at least one superheater by at least one baffle wall; an evaporator coupled downstream of the high temperature section, the evaporator being configured to extract heat from the gas exiting the high temperature section; and a damper system upstream of the evaporator, the damper system being configured to divert the gas exiting from the outlet of the first reheater and the outlet of the at least one superheater.

[0043] The heat recovery steam generator according to any one of the preceding clauses, wherein the damper system includes a superheater damper coupled to the outlet of the at least one superheater and a reheater damper coupled to the outlet of the first reheater.

[0044] The heat recovery steam generator according to any one of the preceding clauses, wherein each of the superheater damper and the reheater damper is selectively movable from a fully open position to a closed position and any position between the fully open position and the fully closed position.

[0045] The heat recovery steam generator according to any one of the preceding clauses, wherein when moved to the fully open position, gas flows uninterruptedly through the at least one superheater and the first reheater.

[0046] The heat recovery steam generator according to any one of the preceding clauses, wherein placing the reheater damper in the closed position causes the exhaust gas to be diverted towards the superheater.

[0047] The heat recovery steam generator according to any one of the preceding clauses, wherein placing the reheater damper in a partially open position creates a pressure difference between the first reheater and the at least one superheater, such that the airflow through the first reheater is reduced.

[0048] The heat recovery steam generator according to any one of the preceding clauses, wherein the reheater damper and the superheater damper are each at least one of a louver, a flap deflector damper, a series damper, and a butterfly damper.

[0049] The heat recovery steam generator according to any one of the preceding clauses, wherein the damper system includes a reheater damper connected to the inlet of the first reheater, and the reheater damper is selectively movable from a fully open position to a fully closed position and any intermediate position between the fully open position and the fully closed position.

[0050] The heat recovery steam generator according to any one of the preceding clauses, wherein the reheater damper selectively reduces the airflow to the first reheater, and the reheater damper selectively redirects the exhaust gas toward the at least one superheater by selectively moving the reheater damper to any position from the fully open position to the fully closed position.

[0051] The heat recovery steam generator according to any one of the preceding clauses, wherein the at least one baffle wall positioned between the first reheater and the at least one superheater is porous, such that gas can partially enter the first reheater from the at least one superheater.

[0052] The heat recovery steam generator according to any one of the preceding clauses, wherein the at least one baffle wall positioned between the first reheater and the at least one superheater includes an opening, such that gas can partially enter the first reheater from the at least one superheater.

[0053] The heat recovery steam generator according to any one of the preceding clauses, wherein the at least one baffle wall positioned between the first reheater and the at least one superheater extends a certain distance from the outlet of the first reheater, such that gas can partially enter the first reheater from the at least one superheater.

[0054] The heat recovery steam generator according to any one of the preceding clauses, wherein the high temperature section includes a second reheater in series orientation with the first reheater, and a baffle wall between the second reheater and the adjacent superheater.

[0055] A heat recovery steam generator according to any one of the preceding clauses, wherein the first reheater and the second reheater are separated by an embedded air damper, and the embedded air damper is positioned to control the air flow between the first reheater and the second reheater.

[0056] A heat recovery steam generator according to any one of the preceding clauses, wherein the embedded air damper selectively reduces the air flow to the second reheater, and the embedded air damper selectively redirects the exhaust gas towards the at least one superheater, such that the embedded air damper in a partially closed position creates a pressure differential between the at least one superheater and the second reheater in a parallel arrangement.

[0057] A heat recovery steam generator according to any one of the preceding clauses, wherein the embedded air damper is at least one of a louver, a flap deflector, a series air damper, and a butterfly air damper.

[0058] A power generation system, comprising: a gas turbine configured to generate electricity and discharge exhaust gas through an exhaust port; and a heat recovery steam generator having a gas inlet in communication with the exhaust port of the gas turbine, the heat recovery steam generator comprising: a high temperature section including a first reheater coupled to at least one high pressure superheater in a parallel orientation, the first reheater being separated from the at least one superheater by at least one partition wall; an evaporator coupled downstream of the high temperature section, the evaporator being configured to extract heat from the gas leaving the high temperature section; and an air damper system upstream of the evaporator, the air damper system being configured to redirect the gas exiting from the outlet of the first reheater and the outlet of the at least one superheater.

[0059] A power generation system according to any one of the preceding clauses, wherein the air damper system includes a reheater air damper coupled to the inlet of the first reheater, the reheater air damper being selectively movable from a fully open position to a fully closed position and any intermediate position therebetween.

[0060] A power generation system according to any one of the preceding clauses, wherein the high temperature section includes a second reheater in a series orientation with the first reheater, wherein the first reheater and the second reheater are separated by an embedded air damper, and the embedded air damper is positioned to control the air flow between the first reheater and the second reheater.

Claims

1. A heat recovery steam generator, comprising: High temperature section, the high temperature section includes a first reheater connected to at least one high-pressure superheater in a parallel orientation, and the first reheater is separated from the at least one superheater by at least one baffle wall; Evaporator, the evaporator is connected downstream of the high temperature section, and the evaporator is configured to extract heat from the gas leaving the high temperature section; and Damper system, the damper system is upstream of the evaporator, and the damper system is configured to deflect the gas leaving the outlet of the first reheater and the outlet of the at least one superheater.

2. The heat recovery steam generator according to claim 1, wherein the damper system includes a superheater damper connected to the outlet of the at least one superheater and a reheater damper connected to the outlet of the first reheater.

3. The heat recovery steam generator according to claim 2, wherein each of the superheater damper and the reheater damper is capable of selectively moving from a fully open position to a closed position and any position between the fully open position and the fully closed position.

4. The heat recovery steam generator according to claim 3, wherein when moved to the fully open position, gas flows continuously through the at least one superheater and the first reheater.

5. The heat recovery steam generator according to claim 3, wherein placing the reheater damper in the closed position causes the exhaust gas to turn towards the at least one superheater.

6. The heat recovery steam generator according to claim 3, wherein placing the reheater damper in a partially open position creates a pressure difference between the first reheater and the at least one superheater, causing the airflow through the first reheater to decrease.

7. The heat recovery steam generator according to claim 2, wherein each of the reheater damper and the superheater damper is at least one of a louver, a flap deflector damper, a series damper, and a butterfly damper.

8. The heat recovery steam generator according to claim 1, wherein the damper system includes a reheater damper connected to the inlet of the first reheater, and the reheater damper is capable of selectively moving from a fully open position to a fully closed position and any intermediate position between the fully open position and the fully closed position.

9. The heat recovery steam generator according to claim 8, wherein the reheater damper selectively reduces the airflow to the first reheater, and the reheater damper selectively turns the exhaust gas towards the at least one superheater by selectively moving the reheater damper to any position from the fully open position to the fully closed position.

10. The heat recovery steam generator according to claim 8, wherein the at least one partition wall located between the first reheater and the at least one superheater is porous, such that gas can partially enter the first reheater from the at least one superheater.

11. The heat recovery steam generator according to claim 8, wherein the at least one baffle wall positioned between the first reheater and the at least one superheater includes an opening such that gas can partially enter the first reheater from the at least one superheater.

12. The heat recovery steam generator according to claim 8, wherein the at least one baffle wall positioned between the first reheater and the at least one superheater extends a certain distance from the outlet of the first reheater such that gas can partially enter the first reheater from the at least one superheater.

13. The heat recovery steam generator according to claim 1, wherein the high temperature section includes a second reheater in a series orientation with the first reheater.

14. The heat recovery steam generator according to claim 13, wherein the first reheater and the second reheater are separated by an embedded air damper, and the embedded air damper is positioned to control the air flow between the first reheater and the second reheater.

15. The heat recovery steam generator according to claim 14, wherein the embedded air damper selectively reduces the air flow to the second reheater, and the embedded air damper selectively redirects the exhaust gas towards the at least one superheater such that the embedded air damper in a partially closed position creates a pressure difference between the at least one superheater and the second reheater in a parallel arrangement.

16. The heat recovery steam generator according to claim 14, wherein the embedded air damper is at least one of a louver, a flap deflector, a series air damper, and a butterfly air damper.

17. A power generation system, comprising: Gas turbine, the gas turbine is configured to generate electricity and discharge exhaust gas through an exhaust port; And Heat recovery steam generator, the heat recovery steam generator has a gas inlet communicating with the exhaust port of the gas turbine, and the heat recovery steam generator includes: High temperature section, the high temperature section includes a first reheater connected to at least one high-pressure superheater in a parallel orientation, and the first reheater is separated from the at least one superheater by at least one baffle wall; Evaporator, the evaporator is connected downstream of the high temperature section, and the evaporator is configured to extract heat from the gas leaving the high temperature section; and Damper system, the damper system is upstream of the evaporator, and the damper system is configured to deflect the gas leaving the outlet of the first reheater and the outlet of the at least one superheater.

18. The power generation system according to claim 17, wherein the air damper system includes a reheater air damper coupled to the inlet of the first reheater, and the reheater air damper is capable of selectively moving from a fully open position to a fully closed position and any intermediate position between the fully open position and the fully closed position.

19. The power generation system according to claim 17, wherein the high temperature section includes a second reheater in a series orientation with the first reheater, wherein the first reheater and the second reheater are separated by an embedded air damper, and the embedded air damper is positioned to control the air flow between the first reheater and the second reheater.

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