Systems and methods of operation to improve power plant start-up operations

Abstract

A combined cycle (CC) power plant includes a gas turbine, heat recovery steam generator (HRSG), steam turbine, and a controller assembly. The gas turbine configured to discharge exhaust gases. The HRSG configured to receive exhaust gases. The HRSG configured to discharge a steam flow. The steam turbine configured to receive the steam flow from the HRSG. The controller assembly downstream from the HRSG includes a flow divider cooperating with a set of control valves. The set of control valves includes at least a first valve to facilitate controlling steam flow to the steam turbine, and at least a second valve to facilitate controlling steam flow to the external consumer. The flow divider is orientated to variably direct a first portion of steam discharged from the HRSG towards an external consumer, and a second portion of steam towards the steam turbine during start-up or normal operations of the CC power plant.

Description

700623 -WO- 1(17851-1499)SYSTEMS AND METHODS OF OPERATION TO IMPROVE POWER PLANT START-UP OPERATIONSFIELD OF THE INVENTION

[0001] The present application relates generally to steam generation systems, and more particularly, to systems and methods for exporting steam from power generation systems during start-up operating conditions.BACKGROUND

[0002] At least some power generation systems include a gas generation system and / or a steam generation system. The gas generation system generally includes a gas turbine engine that is powered by the combustion of a fuel such as hydrocarbons. Within the steam generation system, a steam turbine is often powered by steam supplied by a steam generator. A condenser is used to convert steam received into condensate for use in the steam generation system.

[0003] The start-up operations of at least some known power generations systems may be a lengthy and relatively inefficient process as compared to normal operating conditions. During start-up operations, often the condensate and power generation components require controlled heating to raise the operating temperature to a normal operating range. In particular, during start-up operations, the combustion process is not fully optimized which may lead to inefficient and / or incomplete burning of fuel, and / or increased emissions per unit energy produced. To facilitate improving the start-up operations, at least some known generations systems include an auxiliary boiler to provide auxiliary steam for heating during start up. Furthermore, during start-up operations, CO2 capture rates are typically far less than are possible during normal operations.

[0004] Accordingly, it is desirable to have systems and methods of operation that can facilitate improving start-up operations in a cost-effective and reliable manner.700623 -WO- 1(17851-1499)BRIEF SUMMARY

[0005] In one aspect, a combined cycle (CC) power plant includes a gas turbine, heat recovery steam generator (HRSG), steam turbine, and a controller assembly. The gas turbine is configured to discharge exhaust gases. The HRSG is downstream from the gas turbine for receiving the exhaust gases discharged from the gas turbine. The HRSG is configured to discharge a steam flow and an exhaust gas flow. The steam turbine is configured to receive the steam flow from the HRSG. The controller assembly is downstream from the HRSG including a flow divider cooperating with a set of control valves. The set of control valves includes at least a first valve to facilitate controlling steam flow to the steam turbine, and at least a second valve to facilitate controlling steam flow to the external consumer. The flow divider is orientated to variably direct a first portion of steam discharged from the HRSG towards an external consumer, and a second portion of steam towards the steam turbine during start-up or normal operations of the CC power plant.

[0006] In another aspect, a method of operating a power generation system during start-up operations is provided. The method includes generating a steam flow within a power generation system, directing the steam flow to a controller assembly, variably dividing the steam flow into a first portion and a second portion, directing the first portion of the steam flow towards a steam turbine; and directing the second portion of the steam flow towards an external consumer during start-up operations.

[0007] Advantages will become more apparent to those skilled in the art from the following description of the preferred embodiments which have been shown and described by way of illustration. As will be realized, the present embodiments may be capable of other and different embodiments, and their details are capable of modification in various respects. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The Figures described below depict various aspects of the systems and methods disclosed therein. It should be understood that each Figure depicts an exemplary embodiment of a particular aspect of the disclosed systems and methods, and that each of the700623 -WO- 1(17851-1499)Figures is intended to accord with a possible embodiment thereof. Further, wherever possible, the following description refers to the reference numerals included in the following Figures, in which features depicted in multiple Figures are designated with consistent reference numerals.

[0009] FIG. 1 is a schematic illustration of an exemplary power generation system start¬ up steam export apparatus;

[0010] FIG. 2 is a schematic illustration of an exemplary power generation system startup steam export apparatus of FIG. 1 and coupled to a controller, a temperature regulator, and a pressure regulator;

[0011] FIG. 3 is a schematic illustration of the start-up steam export apparatus of FIG. 2 and coupled to a gas turbine and to a heat recovery steam generator;

[0012] FIG. 4 is a schematic illustration of the start-up steam export apparatus of FIG. 3 with a multiple steam turbine configuration;

[0013] FIG. 5 is a flow chart of an exemplary method of operating a power generation system including a start-up steam export apparatus.

[0014] Unless otherwise indicated, the drawings provided herein are meant to illustrate exemplary features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.DETAILED DESCRIPTION OF THE DRAWINGS

[0015] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.

[0016] The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otheiwise.700623 -WO- 1(17851-1499)

[0017] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0018] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and / or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

[0019] As used herein, the term “database” may refer to either a body of data, a relational database management system (RDBMS), or to both, and may include a collection of data including hierarchical databases, relational databases, flat file databases, object-relational databases, object oriented databases, and / or another structured collection of records or data that is stored in a computer system. The above examples are not intended to limit in any way the definition and / or meaning of the term database. Examples of RDBMS’s include, but are not limited to, Oracle® Database, MySQL, IBM® DB2, Microsoft® SQL Server, Sybase®, and PostgreSQL. However, any database may be used that enables the systems and methods described herein. (Oracle is a registered trademark of Oracle Corporation, Redwood Shores, California; IBM is a registered trademark of International Business Machines Corporation, Armonk, New York; Microsoft is a registered trademark of Microsoft Corporation, Redmond, Washington; and Sybase is a registered trademark of Sybase, Dublin, California.)

[0020] A computer program of one embodiment is embodied on a computer-readable medium. In an example, the system is executed on a single computer system, without requiring a connection to a server computer. In a further example embodiment, the system is being run in a Windows® environment (Windows is a registered trademark of Microsoft Corporation, Redmond, Washington). In yet another embodiment, the system is run on a mainframe environment and a UNIX® server environment (UNIX is a registered trademark of X / Open Company Limited located in Reading, Berkshire, United Kingdom). In a further700623 -WO- 1(17851-1499)embodiment, the system is run on an iOS® environment (iOS is a registered trademark of Cisco Systems, Inc. located in San Jose, CA). In yet a further embodiment, the system is run on a Mac OS® environment (Mac OS is a registered trademark of Apple Inc. located in Cupertino, CA). In still yet a further embodiment, the system is run on Android® OS (Android is a registered trademark of Google, Inc. of Mountain View, CA). In another embodiment, the system is run on Linux® OS (Linux is a registered trademark of Linus Torvalds of Boston, MA). The application is flexible and designed to run in different environments without compromising any major functionality. In some embodiments, the system includes multiple components distributed among a plurality of computer devices. One or more components may be in the form of computer-executable instructions embodied in a computer-readable medium. The systems and processes are not limited to the specific embodiments described herein. In addition, components of each system and each process can be practiced independently and separately from other components and processes described herein. Each component and process can also be used in combination with other assembly packages and processes.

[0021] As used herein, the terms “processor” and “computer” and related terms, e.g., “processing device,” “computer device,” and “controller” are not limited to just those integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit (ASIC), and other programmable circuits, and these terms are used interchangeably herein. In the embodiments described herein, memory may include, but is not limited to, a computer-readable medium, such as a random-access memory (RAM), and a computer-readable non-volatile medium, such as flash memory. Alternatively, a floppy disk, a compact disc - read only memory (CD-ROM), a magneto-optical disk (MOD), and / or a digital versatile disc (DVD) may also be used. Also, in the embodiments described herein, additional input channels may be, but are not limited to, computer peripherals associated with an operator interface such as a mouse and a keyboard. Alternatively, other computer peripherals may also be used that may include, for example, but not be limited to, a scanner. Furthermore, in the exemplary embodiment, additional output channels may include, but not be limited to, an operator interface monitor.700623 -WO- 1(17851-1499)

[0022] Further, as used herein, the terms “software” and “firmware” are interchangeable and include any computer program storage in memory for execution by personal computers, workstations, clients, servers, and respective processing elements thereof.

[0023] As used herein, the term “non-transitory computer-readable media” is intended to be representative of any tangible computer-based device implemented in any method or technology for short-term and long-term storage of infomiation, such as, computer-readable instructions, data structures, program modules and sub-modules, or other data in any device. Therefore, the methods described herein may be encoded as executable instructions embodied in a tangible, non-transitory, computer readable medium, including, without limitation, a storage device, and a memory device. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein. Moreover, as used herein, the term “non-transitory computer-readable media” includes all tangible, computer-readable media, including, without limitation, non-transitory computer storage devices, including, without limitation, volatile and nonvolatile media, and removable and non-removable media such as a firmware, physical and virtual storage, CD-ROMs, DVDs, and any other digital source such as a network or the Internet, as well as yet to be developed digital means, with the sole exception being a transitory, propagating signal.

[0024] Furthermore, as used herein, the term “real-time” refers to at least one of: the time of occurrence of the associated events, the time of measurement and collection of predetermined data, the time for a computer device (e.g., a processor) to process the data, and / or the time of a system response to the events and the environment. In the embodiments described herein, these activities and events may be considered to occur substantially instantaneously.

[0025] The embodiments described herein relate generally to systems and methods for operating a power generation system. More specifically, at least some of the systems and methods described herein describe methods and systems that facilitate exporting steam from a power generation system to an external consumer during start-up operations. In the exemplary embodiments, a steam exportation apparatus selectively divides a steam flow during start-up operations of the power generation system. More specifically, in the exemplary embodiments, the power generation system includes a steam generator that discharges a steam flow, and a steam turbine that is downstream from the steam generator700623 -WO- 1(17851-1499)and that creates mechanical motion using the steam flow received from the steam generator. A controller assembly downstream from the steam generator includes a flow divider that is orientated to direct a first portion of steam discharged from the steam generator to the steam turbine and a second portion of the steam discharged from the steam generator to an external consumer during start-up operations.

[0026] In the exemplary embodiment the power generation system includes a thermal energy regulator that selectively adjusts the thermal energy of the second steam flow upstream from the external consumer. More specifically, in the exemplary embodiment, the second steam flow may be routed through a device, such as a steam attemperator, steam extraction valve, or desuperheater, to facilitate reducing the second steam flow to a desired temperature and / or to a desired quality prior to the second steam flow reaching the external consumer. The thermal energy regulator may be manually or automatically operated to enable the desired temperature and / or quality to be satisfied. Moreover, the desired temperature and / or quality may be predefined or may be continuously adjusted to satisfy the requirements of the specific external consumer. The power generation system may also include a pressure regulator to enable the pressure of the second steam flow upstream from the external consumer to be selectively varied. More specifically, in the exemplary embodiment, the second steam flow may be routed through a device, such as a butterfly pressure control valve, to enable the pressure of the second steam flow to be variably adjusted, manually and / or automatically, to satisfy the requirements of the specific external consumer.

[0027] The exemplary embodiments described herein enable the export of steam from a power generation system during start-up operations while overcoming several technical challenges associated with the same. Exporting steam from a power generation system during start-up operations, as described herein, utilizes excess steam and thus facilitates improving the overall efficiency of the power generation system, while providing a supplemental steam flow required for an external consumer. Moreover, exporting steam to an external consumer, facilitates reducing an amount of steam potentially required by an external consumer, such as an onsite carbon capture unit used to facilitate reducing emissions generated by the power generation system, for example.700623 -WO- 1(17851-1499)

[0028] The present embodiments may relate to, inter alia, steam exportation systems and methods that may be implemented during start-up conditions of a power generation system to facilitate improving the overall efficiency of the system.

[0029] Referring now to the drawings, FIG. 1 is a schematic illustration of an exemplary power generation system including a start-up steam export apparatus 100. In the exemplary embodiment, the start-up steam export apparatus 100 includes a steam generator 102 that discharges a steam flow 104. A flow divider 106, downstream from the steam generator 102, enables the steam flow 104 to be variably split into at least two steam streams 108 and 112, for example. At least one of the streams 108 is channeled towards a steam turbine 110, and at least one of the streams 112 is channeled to an external process or external consumer 114.

[0030] The steam generator 102 may be any device that facilitates increasing the thermal energy of a liquid aqueous solution beyond its boiling point, such that the liquid aqueous solution is converted to a gas. Exemplary steam generators may include, but are not limited to only including, benson boilers, and / or heat recovery steam generators (HRSG). Additives such as scale inhibitors, oxygen scavengers, amines, and alkalinity builders may be added to the liquid or gas aqueous solution to facilitate improving desired qualities of the steam. In some embodiments, the external process 114 can be a carbon capture plant or any other process that uses steam as a working fluid, heat transfer medium, or precursor.

[0031] Although the exemplary embodiment includes flow divider 106, alternatively, the start-up steam export apparatus 100 may be coupled to any other device that enables an incoming flow approaching the apparatus 100 to be split or divided into multiple outgoing flows downstream from the apparatus 100. For example, in alternative embodiments, instead of, or in addition to, the flow divider 106, at least one channel restrictor, at least one flow regulator, and / or a series of selectively openable and closeable valving may be used. The composition of each flow downstream from the flow divider 106 are substantially homogenous, and in the exemplary embodiment, the flow divider 106 can be variably positioned to enable a desired proportion or division of the steam flow.

[0032] FIG. 2 is a schematic illustration of an exemplary power generation system startup steam export apparatus 200 that may be used with the power generation system shown in FIG. 1. In the exemplary embodiment, start-up apparatus 200 includes a controller 120, a700623 -WO- 1(17851-1499)temperature or thermal energy regulator 202, and a pressure regulator 204. In the exemplary embodiment, the thermal energy regulator 202 selectively adjusts the thermal energy of the second steam flow 112 upstream from the external consumer 114 to ensure that steam having desired qualities is provided to the external consumer 114. More specifically, in some embodiments, the second steam flow 112 may be channeled through a device such as, but not limited to only being, a steam attemperator or desuperheater, to facilitate tempering the second steam flow 112 to a desired temperature and / or quality prior to the external consumer 114 receiving the second steam flow 112. The thermal energy regulator 202 may be manually and / or automatically operated to ensure the steam satisfies the desired temperature and / or quality. In some embodiments, the thermal regulator 202 may be adjusted with predetermined or predefined adjustments, and / or may be continuously automatically adjusted to satisfy the requirements of the external consumer 114.

[0033] In some embodiments, the start-up steam export apparatus 200 described herein may also include a pressure regulator 204 to enable the operating pressure of the second steam flow 112 to be variably adjusted upstream from the external consumer 114. More specifically, in some embodiments, the second steam flow 112 may be channeled through any other regulating device that enables the operating pressure of the second steam flow 112 to be variably adjusted to satisfy the requirements of the specific external consumer 114. In the exemplary embodiment, the pressure regulator 204 may be manually or automatically operated, and / or to satisfy the desired pressure that may be predetermined or continuously adjusted in real-time.

[0034] In some embodiments, the proportion of each steam flow 108 and 112, for example, exiting the flow divider 106 can be variably adjusted by a controller 120 that includes a processor (not shown). The controller 120, may continuously monitor the power generation system in real-time to determine the proportion of each stream 108 and 112 exiting the flow divider 106 based on the steam turbine 110 temperature, i.e., detected steam turbine rotor temperature, speed, i.e., detected steam turbine acceleration and / or loading, and / or based on detected and / or predefined stress limits, such as steam turbine allowable stress limitations, for example. In each embodiment, the controller 120 facilitates maintaining optimal steam flow through the steam turbine required during various stages of start-up, such that windage issues, and / or overloading of the latter stage blades is facilitated to be prevented.700623 -WO- 1(17851-1499)

[0035] FIG. 3 is a schematic illustration of an exemplary system start-up steam export apparatus 300 that may be used with the power generation system shown in FIG. 1 and FIG.2. In the exemplary embodiment, the steam export apparatus 300 includes at least one gas turbine 302 and at least one heat recovery steam generator (HRSG) 304. In the exemplary embodiment, the gas turbine 302 produces hot exhaust gases by combusting a fuel mixture within. The hot exhaust gases are channeled from the turbine 302 towards the HRSG 304 wherein steam is generated by transferring the thermal energy from the hot exhaust gases to the liquid aqueous solution. In some embodiments the proportion of each flow exiting the flow divider 106 can be variably adjusted in real-time via a controller 120 including a processor. The controller 120, may continuously monitor the power generation system 300 to determine the proportion of each stream 108 and 112, for example, exiting the flow divider 106 based on the operating variables of the gas turbine 302, steam turbine 110, and / or the HRSG 304 including the temperature, speed, and / or stress of each component.

[0036] In some exemplary embodiments, the controller 120 may also determine the steam extraction from the steam turbine 110. For example, in one embodiment, start-up steam export apparatus 100 initially directs all of the steam generated from steam generator 102 towards the external consumer 114 via the flow divider 106 and steam flow 112. In such an embodiment, flow divider 106 directs a portion of steam flow to steam turbine 110 via steam flow 108, to enable the steam turbine 110 to be started. Incrementally, the proportion of steam being directed to the steam turbine 110 is increased until all of the steam generated from steam generator 102 is directed to steam turbine 110 via steam flow 108.

[0037] FIG. 4 is a schematic illustration of an exemplary start-up steam export apparatus 400 that may be used with the power generation system shown in FIGs. 1-3. In the exemplary embodiment, the power generation system includes a multiple steam turbine configuration 110 including a high-pressure steam turbine 110A, an intermediate pressure steam turbine HOB, and pair of low-pressure steam turbines HOC. Moreover, in the exemplary embodiment, the start-up steam export apparatus 400 includes a plurality of flow dividers 106B and 106C, thermal energy regulators 202B and 202C, and pressure regulators 204B and 204C. Additionally, within the exemplary embodiment, a plurality of steam flows 104B and 104C, first steam flows fO8B and fO8C, and second steam flows 112B and 112C are generated and channeled to various locations. Moreover, a steam flow 402 is channeled700623-WO-l(17851-1499)from the intermediate pressure steam turbine HOB towards the first steam flows 108B and 108C.

[0038] In the exemplary embodiment, the HRSG 304 discharges steam flows 104B and 104C such that flow 104B is directed towards flow divider 106B and steam flow 104C is directed towards flow divider 106C. Flow dividers 106B and 106C are each downstream from the steam generator 102 and are each oriented to split their respective steam flows 104B and 104C into at least two streams each. More specifically, a first steam flow 108B is directed towards the intermediate pressure steam turbine HOB. The steam flow 402 exiting the intermediate pressure steam turbine 110B is combined with the first steam flow 108C downstream from flow divider 106C. The first steam flow' 108C is directed tow ards the pair of low-pressure steam turbines HOC. Moreover, the second steam flow 112B from flow divider 106B is directed towards the pressure regulator 204B and subsequently through the thermal energy regulator 202B before being channeled towards the second steam flow' 112C. The second steam flow' 112C from flow' divider 106C is directed downstream tow ards the pressure regulator 204C prior to being combined with steam flow' 112B. The combined steam flow of H2B and 112C is channeled through the thermal energy regulator 202C prior to the combined flow' 112B and 112C channeled towards the external process 114.

[0039] In some embodiments, the proportion of each flow 108B, 108C, 112B and / or 112C exiting the flow divider 106B and / or 106C can be variably adjusted by a controller 120 including a processor. The controller 120, may continuously monitor the power generation system in real-time to determine the proportion of each steam flow 108B, 108C, 112B and / or 112C exiting each flow' divider 106B and / or 106C based on the operating variables associated with any of the high-pressure steam turbine 110A, the intermediate pressure steam turbine HOB, the pair of low-pressure steamturbines HOC, gas turbine 302, steam demand of the external consumer 114, and / or the heat recovery steam generator 304 temperature, speed, or stress.

[0040] FIG. 5 is a flow' chart of an exemplary method that may be implemented to operate a power generation system during start-up operations, such as power generation system (shown in FIGs. 1-4). In the exemplary' embodiment, the method 500 includes generating 502 a steam flow within a power generation system and directing 504 the steam flow downstream towards a controller assembly. Method 500 also includes variably dividing 506700623-WO-l(17851-1499)the steam flow into at least a first portion and a second portion. The first portion of the steam flow is directed 510 towards to a steam turbine, and the second portion of the steam flow is directed 510 towards an external process or consumer during start-up operations of the power generation system.

[0041] In each embodiment, the inclusion of a start-up steam export apparatus facilitates utilizing excess steam produced by a steam generator during start-up operations and channeling the excess steam towards an external consumer. Utilization of the excess steam produced during the power generation systems start-up operations can facilitate reducing supplemental steam generation requirements of the external consumer during start-up operations. As a result, the exportation facilitates reducing the physical size of an auxiliary7steam generator needed during power generation start up operations. Moreover, the exportation of the excess steam facilities reducing the overall costs associated with operation of the power generation system, while facilitating improving the overall efficiency of operation of the power generation system. Overall, the exportation system described herein facilitates improving the efficiency of the power generation system reducing the initial capital expenditures and long-term operating costs associated with the power generation systems.

[0042] Further aspects of the present disclosure are provided by the subject matter of the following clauses:

[0043] A combined cycle (CC) power plant including a gas turbine configured to discharge exhaust gases, a heat recovery steam generator (HRSG) downstream from the gas turbine for receiving the exhaust gases discharged from the gas turbine, the HRSG configured to discharge a steam flow and an exhaust gas flow, a steam turbine configured to receive the steam flow7from the HRSG, and a controller assembly downstream from the HRSG comprising a flow divider cooperating with a set of control valves including at least a first valve to facilitate controlling steam flow to the steam turbine, and at least a second valve to facilitate controlling steam flow to the external consumer, wherein the flow divider is orientated to variably direct a first portion of steam discharged from the HRSG towards an external consumer, and a second portion of steam tow ards the steam turbine during start-up or normal operations of the CC power plant.700623-WO-l(17851-1499)

[0044] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly set of control valves include at least one of a butterfly pressure control valve, and a steam extraction control valve.

[0045] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly further comprises a thermal energy' regulator configured to variably adjust the thermal energy of the first steam flow upstream of the external consumer.

[0046] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly further comprises, a first pressure regulator configured to variably adjust the pressure of the first steam flow to the external consumer, and a second pressure regular configured to variably adjust the pressure of the second steam flow to steam turbine

[0047] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly is configured to direct the first portion of the steam from the steam generator towards a carbon capture system.

[0048] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly is configured to variably adjust the proportion of the second steam flow based on a detected steam turbine rotor temperature.

[0049] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly is configured to variably adjust the proportion of the first and second steam flows based on a detected steam turbine acceleration and loading.

[0050] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly is configured to variably adjust the proportion of the first and second steam flow based on detected steam turbine allowable stress limitations.

[0051] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly is configured to variably adjust the proportion of the first and steam extraction flows from the steam turbine based on a predetermined steam turbine acceleration and loading.700623-WO-l(17851-1499)

[0052] The combined cycle power plant in accordance with any of the preceding clauses, wherein the controller assembly is configured to variably adjust the proportion of the first and second steam flow based on predetermined steam turbine allowable stress limitations.

[0053] A method of operating a power generation system during start-up operations, the method including, generating a steam flow within a power generation system, directing the steam flow to a controller assembly, variably dividing the steam flow into a first portion and a second portion, directing the first portion of the steam flow towards a steam turbine, and directing the second portion of the steam flow towards an external consumer during start-up operations.

[0054] The method in accordance with any of the preceding clauses further including directing a first portion of steam discharged from the HRSG towards an external consumer, and a second portion of steam towards the steam turbine during start-up operations of the CC power plant.

[0055] The method in accordance with any of the preceding clauses further including regulating the thermal energy of the second portion of the steam flow prior to directing the second portion of the steam flow towards the external consumer.

[0056] The method in accordance with any of the preceding clauses further including regulating the pressure of the second portion of the steam flow prior to directing the second portion of the steam flow towards the external consumer.

[0057] The method in accordance with any of the preceding clauses further including directing the first portion of the steam from the steam generator towards a carbon capture system.

[0058] The method in accordance with any of the preceding clauses further including variably adjusting the proportion of the second steam flow based on a detected steam turbine rotor temperature.

[0059] The method in accordance with any of the preceding clauses further including variably adjusting the proportion of the first and second steam flows based on a detected steam turbine acceleration and loading.700623-WO-l(17851-1499)

[0060] The method in accordance with any of the preceding clauses further including variably adjusting the proportion of the first and second steam flow based on detected steam turbine allowable stress limitations.

[0061] The method in accordance with any of the preceding clauses further including variably adjusting the proportion of the first and steam extraction flows from the steam turbine based on a predetermined steam turbine acceleration and loading.

[0062] The method in accordance with any of the preceding clauses further including variably adjusting the proportion of the first and second steam flow based on predetermined steam turbine allowable stress limitations.

[0063] The exemplary systems and methods described and illustrated herein therefore significantly improves the start-up operations of power generation systems by channeling excess steam generation to an external process, thus reducing the steam requirements of the external consumer. Moreover, the systems and methods described herein facilitate reducing the physical size of an auxiliary boiler that may be required, as well as reducing the cost of the power generation system while improving the efficiency of the power generation system as compared to conventional power generation systems.

[0064] Exemplary embodiments of systems and methods for extracting steam during power generation start-up operations are described above in detail. The systems and methods of this disclosure though, are not limited to only the specific embodiments described herein, but rather, the components and / or steps of their implementation may be utilized independently and separately from other components and / or steps described herein.

[0065] Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the systems and methods described herein, any feature of a drawing may be referenced or claimed in combination with any feature of any other drawing.

[0066] Some embodiments involve the use of one or more electronic or computer devices. Such devices typically include a processor, processing device, or controller, such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an application specific integrated700623-WO-l(17851-1499)circuit (ASIC), a programmable logic circuit (PLC), a programmable logic unit (PLU), a field programmable gate array (FPGA), a digital signal processing (DSP) device, and / or any other circuit or processing device capable of executing the functions described herein. The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and / or a memory device. Such instructions, when executed by a processing device, cause the processing device to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and / or meaning of the term processor and processing device.

[0067] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

[0068] The above description is meant to be exemplary' only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the disclosure. Modifications, which fall within the scope of the present disclosure, will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims. The systems and methods described herein are not limited to the specific embodiments described herein, but rather components of the various systems may be utilized independently and separately from other systems and components described herein. For example, the steam exportation apparatus can be implemented and utilized in connection with any application where steam exportation is desired to be used with any start-up operation.

Claims

700623-WO-l(17851-1499)WE CLAIM:

1. A combined cycle (CC) power plant comprising:a gas turbine configured to discharge exhaust gases;a heat recovery steam generator (HRSG) downstream from the gas turbine for receiving the exhaust gases discharged from the gas turbine, the HRSG configured to discharge a steam flow and an exhaust gas flow;a steam turbine configured to receive the steam flow from the HRSG; and a controller assembly downstream from the HRSG comprising a flow divider cooperating with a set of control valves including at least a first valve to facilitate controlling steam flow to the steam turbine, and at least a second valve to facilitate controlling steam flow to the external consumer, wherein the flow divider is orientated to variably direct a first portion of steam discharged from the HRSG towards an external consumer, and a second portion of steam towards the steam turbine during start-up or normal operations of the CC power plant.

2. The CC power plant of claim 1 , w herein the controller assembly set of control valves include at least one of a butterfly pressure control valve, and a steam extraction control valve.

3. The CC power plant of claim 1, wherein the controller assembly further comprises athermal energy regulator configured to variably adjust the thermal energy of the first steam flow' upstream of the external consumer.

4. The CC power plant of claim 1, wherein the controller assembly further comprises:a first pressure regulator configured to variably adjust the pressure of the first steam flow to the external consumer; anda second pressure regular configured to variably adjust the pressure of the second steam flow to steam turbine.

5. The CC power plant of claim 1, wherein the controller700623-WO-l(17851-1499)assembly is configured to direct the first portion of the steam from the steam generator towards a carbon capture system.

6. The CC power plant of claim 1. wherein the controller assembly is configured to variably adjust the proportion of the second steam flow based on a detected steam turbine rotor temperature.

7. The CC power plant of claim 1. wherein the controller assembly is configured to variably adjust the proportion of the first and second steam flows based on a detected steam turbine acceleration and loading.

8. The CC power plant of claim 1. wherein the controller assembly is configured to variably adjust the proportion of the first and second steam flow based on detected steam turbine allowable stress limitations.

9. The CC power plant of claim 1. wherein the controller assembly is configured to variably adjust the proportion of the first and steam extraction flows from the steam turbine based on a predetermined steam turbine acceleration and loading.

10. The CC power plant of claim 1. wherein the controller assembly is configured to variably adjust the proportion of the first and second steam flow based on predetermined steam turbine allowable stress limitations.

11. A method of operating a power generation system during start-up operations, the method comprising:generating a steam flow' within a power generation system;directing the steam flow to a controller assembly;variably dividing the steam flow into a first portion and a second portion; directing the first portion of the steam flow' towards a steam turbine; and directing the second portion of the steam flow towards an external consumer during start-up operations.700623-WO-l(17851-1499)12. The method of claim 11 further comprising directing a first portion of steam discharged from the HRSG towards an external consumer, and a second portion of steam towards the steam turbine during start-up operations of the CC power plant.

13. The method of claim 11 further comprising regulating the thermal energy of the second portion of the steam flow prior to directing the second portion of the steam flow towards the external consumer.

14. The method of claim 11 further comprising regulating the pressure of the second portion of the steam flow prior to directing the second portion of the steam flow towards the external consumer.

15. The method of claim 11 further comprising directing the first portion of the steam from the steam generator towards a carbon capture system.

16. The method of claim 11 further comprising variably adjusting the proportion of the second steam flow based on a detected steam turbine rotor temperature.

17. The method of claim 11 further comprising variably adjusting the proportion of the first and second steam flows based on a detected steam turbine acceleration and loading.

18. The method of claim 11 further comprising variably adjusting the proportion of the first and second steam flow based on detected steam turbine allowable stress limitations.

19. The method of claim 11 further comprising variably adjusting the proportion of the first and steam extraction flows from the steam turbine based on a predetermined steam turbine acceleration and loading.

20. The method of claim 11 further comprising variably adjusting the proportion of the first and second steam flow based on predetermined steam turbine allowable stress limitations.

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