US20110146276A1 - Method of starting a steam turbine - Google Patents

Abstract

The present invention has the technical effect of reducing the start-up time associated with starting a steam turbine. Embodiments of the present invention provide a new methodology for reducing the steam-to-metal temperature mismatch present during the start-up of a steam turbine. Essentially, embodiments of the invention may raise the pressure of the steam upstream of an admission valve associated with a High Pressure (HP) section of a steam turbine. The initial high pressure of the steam may reduce the enthalpy of steam, reducing temperature of the steam admitted to the HP section.

Description

BACKGROUND OF THE INVENTION
• The present invention relates generally to the operation of a turbomachine, and more particularly, to a method of reducing the start-up time of a steam turbine.
• The start-up and loading process of some known steam turbines, typically involves a plurality phases occurring at different load ranges. One reason for this method of starting and loading the steam turbine is rotor stress control. A rotor of the steam turbine can experience an overstress event during the start-up and the initial loading phases. Overstressing can degrade the material properties of the rotor. A rotor stress control may stage the loading of the steam turbine with the goal of maintaining the rotor stress within an allowable range.
• Known methods of reducing the likelihood of an overstress event involve maintaining the temperature of the steam exiting a boiler, such as, but not limiting of, a Heat Recovery Steam Generator (HRSG) at a relative low temperature. For example, but not limiting of, on a combined cycle powerplant the gas turbine is held at a low load spinning reserve, or the like, to ensure that the temperature of the steam generated within the HRSG is acceptable to the steam turbine. For a cold start, this temperature may around 700 degrees Fahrenheit. A cold start may be considered the start-up of the steam turbine after a period on in operation.
• On combined cycle applications, the steam pressure is typically related to gas turbine load. On a cold start, the gas turbine may limited to operate at a load equivalent to approximately 40% of rated pressure prior to steam turbine start. Due to the relatively low initial upstream pressure, when steam is admitted to the steam turbine, the upstream steam enthalpy is also relatively high. In addition, when steam is admitted to the steam turbine, the pressure ratio across the upstream and downstream admission valves is relatively high. These operational factors may result in steam temperature inside a section of the steam turbine, at the turbine bowl, to be roughly 40-50 degrees Fahrenheit lower than the upstream temperature of the steam. During a cold start of the steam turbine, this reduction in steam temperature may be insufficient to prevent an overstressing event on the turbine rotor.
• Therefore, there is a desire for an improved method of starting a steam turbine. The method should reduce the start-up time. This method should also eliminate or reduce or the level of overstressing experienced by the rotor.
BRIEF DESCRIPTION OF THE INVENTION
• In an embodiment of the present invention, a method of starting a powerplant machine, the method comprising: providing a steam turbine configured for converting steam to a mechanical torque; wherein the steam turbine comprises an HP section; and increasing a pressure of steam upstream of an admission valve to a pressure matching range, wherein the admission valve is located upstream of the HP section; wherein the step of increasing the pressure of the steam decreases a temperature of the steam prior to admission into the HP section.
• In an alternate embodiment of the present invention, a method of starting a powerplant comprising a steam turbine, the method comprising: providing a steam turbine configured for converting steam to a mechanical torque; wherein the steam turbine comprises an HP section and a bypass system; determining whether a cold start of the steam turbine is requested; increasing a pressure the steam upstream of an admission valve to a pressure matching range, wherein the admission valve is located upstream of the HP section; determining whether the steam upstream of the admission valve is within the pressure matching range; initiating a start-up of the steam turbine if a start-up permissive is satisfied; and modulating the admission valve such that allow the steam flows into the HP section; wherein the step of increasing the pressure of the steam decreases a temperature of the steam before steams flows into the HP section.
• In an another alternate embodiment of the present invention, a system configured for starting a steam turbine, the system comprising: a steam turbine configured for converting steam to a mechanical torque; wherein the steam turbine comprises an HP section; and a control system configured for starting the steam turbine, wherein the control system performs the steps of determining whether a cold start of the steam turbine is requested; increasing a pressure the steam upstream of an admission valve to a pressure matching range, before the steam flows into the HP section, wherein an admission valve is located upstream of the HP section; determining whether the steam upstream of the admission valve is within the pressure matching range; initiating a start-up of the steam turbine if a start-up permissive is satisfied; and opening the admission valve to allow the steam to flow into the HP section; wherein the step of increasing the pressure of the steam decreases a temperature of the steam prior to admission into the HP section.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a schematic illustrating a HP section of a steam turbine representing an environment within which an embodiment of the present invention may operate.
• FIG. 2 is a chart illustrating operating curves in accordance with a known method of starting a steam turbine.
• FIG. 3 is a block diagram illustrating a method used to start-up a turbomachine, in accordance with an embodiment of the present invention.
• FIG. 4 is a block diagram illustrating a method used to start-up a turbomachine, in accordance with an alternate embodiment of the present invention.
• FIG. 5 is a chart illustrating operating curves in accordance with a method of starting a steam turbine in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• The present invention has the technical effect of reducing the start-up time associated with starting a steam turbine. Embodiments of the present invention provide a new methodology for reducing the steam-to-metal temperature mismatch present during the start-up of a steam turbine. Essentially, embodiments of the invention may raise the pressure of the steam upstream of an admission valve associated with a High Pressure (HP) section of a steam turbine. The initial high pressure of the steam may reduce the enthalpy of steam, thus reducing temperature of the steam admitted to the HP section.
• Detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms, and should not be construed as limited to only the embodiments set forth herein.
• Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are illustrated by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments.
• It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any, and all, combinations of one or more of the associated listed items.
• The terminology used herein is for describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including”, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
• It should also be noted that in some alternative implementations, the functions/acts noted might occur out of the order noted in the FIGS. Two successive FIGS., for example, may be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/operations involved.
• Referring now to the FIGS., where the various numbers represent like parts throughout the several views.FIG. 1 is a schematic illustrating a HPsection120 of asteam turbine100 representing an environment within which an embodiment of the present invention may operate. Typically, asteam turbine100 typically comprises multiple sections, such as, but not limiting of, a High-Pressure (HP), an Intermediate-Pressure (IP), and a Low-Pressure (LP). Embodiments of the present invention may control the steam flow into the HPsection120. Therefore,FIG. 1 and the following discussion focus on the HPsection120 which is integrated with acondensor140. For simplicity, the IP drum and IP section, the LP drum and LP section, and reheat components are not illustrated inFIG. 1. However, embodiments of the present invention may apply to asteam turbine100 comprising some or all of those sections and components, or the like.
• Acontrol system190 applying known methods of starting up thesteam turbine100 may perform the following steps. Steam from an IP drum may be admitted to the IP section of thesteam turbine100. Next, thesteam turbine100 may accelerate to full-speed-no-load (FSNL). Next, thesteam turbine100 may synchronize with a grid system, or the like. Next, turbine transfer of the steam from the IP section to full flow to the HPsection120 may occur. Here, anadmission valve115 may begin to open, allowing steam to from the HPdrum105 to the HPsection120. Concurrently, thecontrol system190 monitors the rotor stress. If the rotor stresses exceed an allowable range then thecontrol system190 may hold or reduce the steam flow into the HPsection120, for a predetermined waiting period. After, the rotor stresses decrease to an allowable range, thecontrol system190 may continue to admit steam into the HPsection120 via theadmission valve115 until full steam flow is achieved or the steam turbine load meets a load set point.
• FIG. 2 is achart200 illustrating operating curves in accordance with a known method of starting asteam turbine100, as described inFIG. 1. A first vertical axis represents Temperature (in deg. F.) and Pressure (in psia). A second vertical axis represents stress (in percentage). The first and second vertical axes are versus the start-up time (in minutes) on the horizontal axis.Data series205 represents the actual HP rotor stress anddata series210 represents the allowable stress limit.Data series215 and220 represent HP upstream pressure and temperature respectively. The upstream area is illustrated as theupstream location130 inFIG. 1.Data series225 may represent the HP bowl temperature, illustrated asHP bowl125 inFIG. 1.
• Theupstream area130 may be considered a region upstream and adjacent to theadmission valve115. Thedownstream area135 may be considered a region downstream and adjacent to the admission valve115:
• FIG. 2 illustrated that from approximately 8 minutes to approximately 24 minutes, theHP rotor stress205 exceeded theallowable stress limit210. To correct this situation thecontrol system190 may modulate theadmission valve115 towards a closed position for a predetermined waiting period. As illustrated inFIG. 2, at approximately 25 minutes, the rotor stresses decreases to an allowable range. Here, thecontrol system190 may modulate theadmission valve115 towards an open position to continue to admit steam into theHP section120, as described. The period that theHP rotor stress205 exceeded theallowable stress210, approximately 16 minutes, prevented thesteam turbine100 from completing the start-up process.
• As will be appreciated, the present invention may be embodied as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit”, “module,” or “system”. Furthermore, the present invention may take the form of a computer program product on a computer-usable storage medium having computer-usable program code embodied in the medium. As used herein, the terms “software” and “firmware” are interchangeable, and include any computer program stored in memory for execution by a processor, including RAM memory, ROM memory, EPROM memory, EEPROM memory, and non-volatile RAM (NVRAM) memory. The above memory types are exemplary only, and are thus not limiting as to the types of memory usable for storage of a computer program.
• Any suitable computer readable medium may be utilized. The computer-usable or computer-readable medium may be, for example but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, device, or propagation medium. More specific examples (a non exhaustive list) of the computer-readable medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a transmission media such as those supporting the Internet or an intranet, or a magnetic storage device. Note that the computer-usable or computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via, for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. In the context of this document, a computer-usable or computer-readable medium may be any medium that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
• The term processor, as used herein, refers to central processing units, microprocessors, microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASIC), logic circuits, and any other circuit or processor capable of executing the functions described herein.
• Computer program code for carrying out operations of the present invention may be written in an object oriented programming language such as Java7, Smalltalk or C++, or the like. However, the computer program code for carrying out operations of the present invention may also be written in conventional procedural programming languages, such as the “C” programming language, or a similar language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
• The present invention is described below with reference to flowchart illustrations and/or block diagrams of methods, apparatuses (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a public purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
• These computer program instructions may also be stored in a computer-readable memory. These instructions can direct a computer or other programmable data processing apparatus to function in a particular manner. The such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus. These instructions may cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process. Here, the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions/acts specified in the flowchart and/or block diagram blocks.
• Embodiments of the present invention provide a new start-up methodology. As described below, embodiments of this methodology may increase the pressure of the steam upstream of theHP section120. This may reduce the temperature of the steam prior to admission into theHP section120; which may reduce the rotor stresses. Then, during initial steam turbine loading, the methodology may reduce the upstream steam pressure. This may increase the temperature of the steam flowing into theHP section120 to a normal operating range at theHP bowl125.
• Referring again to the Figures,FIG. 3 is a block diagram illustrating amethod300 used to start-up asteam turbine100, in accordance with an embodiment of the present invention. Themethod300 may be operated by thecontrol system190, as illustrated inFIG. 1. Thecontrol system190 may provide a graphical user interface (GUI), or the like, that allows an operator to interact with themethod300.
• Instep305, themethod300 may determine the initial steam turbine metal temperatures. Here, thecontrol system190 may receive data on the metal temperatures from a temperature sensing devices integrated with the rotor of thesteam turbine100.
• Instep310, themethod300 may determine if a cold start of thesteam turbine100 is required. A cold start may be considered a start-up of asteam turbine100 that has been idle for a certain period. Components of thesteam turbine100 typically require longer warming periods when operating under a cold start. Thecontrol system190 may comprise an operating timer, or the like, which determines when a cold start is required. If a cold start is required, then themethod300 may proceed to step315; otherwise themethod300 may proceed to step325.
• Instep315, themethod300 may increase the pressure of the HP steam at theupstream location130 to a matching pressure range. Referring again toFIG. 1, embodiments of the present invention may modulate thebypass valve110 to a position allowing for the matching pressure range. In an embodiment of the present invention, the pressure range may be from approximately 1200 deg. F. to approximately 1500 deg. F.
• Instep320, themethod300 may determine whether the pressure of the steam at theupstream location130 is within the matching pressure range. If the pressure of the steam is within the matching pressure range, then themethod300 may proceed to step325; otherwise themethod300 may revert to step315.
• Instep325, themethod300 may determine whether a start-up permissive is satisfied. Here, thecontrol system190 may include start-up permissives that serve to ensure that various systems of thesteam turbine100 are ready and/or enable for the start-up process. If the start-up permissive is satisfied, then themethod300 may proceed to step330; otherwise themethod300 may revert to step325 until the start-up permissive is satisfied.
• Instep330, themethod300 may initiate the start-up process of thesteam turbine100. Here, steam from an IP drum may be admitted to the IP section of thesteam turbine100. Next, thesteam turbine100 may accelerate to full-speed-no-load (FSNL).
• In step335, themethod300 may synchronize thesteam turbine100. Here, thesteam turbine100 may be electrically connected with a grid system, or the like.
• Instep340, themethod300 may begin to modulate theadmission valve115. This may allow steam from theHP drum105 to fill and warm the piping adjacent theHP section120.
• Instep345, themethod300 may transfer to full flow of the steam from the IP section to theHP section120. Here, theadmission valve115 may further open, allowing steam to enter theHP section120.
• Instep350, themethod300 may determine if the rotor stress level is allowable. Here, thecontrol system190 may monitor the rotor stress in real-time and compare the actual rotor stress to the allowable stress limit. If the rotor stresses are not in the allowable range, then themethod300 may proceed to step355; otherwise themethod300 may proceed to step360.
• Instep355, themethod300 may maintain or reduce the steam flow into theHP section120, for a predetermined waiting period. After, the rotor stresses decrease to the allowable range; thecontrol system190 may continue to admit steam into theHP section120 via theadmission valve115.
• Instep360, themethod300 may increase the temperature of the steam at theupstream location130 to approximately a rated temperature. Here, thecontrol system190 may modulate thebypass valve110 to a position allowing for decreasing the pressure of the steam, allowing for an increasing the steam temperature, as described.
• Instep365, themethod300 may increase the temperature of the steam in theHP bowl125. Here, thecontrol system190 may modulate thebypass valve110 to a position allowing for decreasing the pressure of the steam, allowing for an increasing the steam temperature, as described.
• Instep370, themethod300 may increase the load to a base load, or other load setpoint. Here, thecontrol system190 may continue to admit steam into theHP section120 via theadmission valve115 until the desired load is reached.
• Instep375, themethod300 may maintain the load setpoint. Here, themethod300 may modulate theadmission valve115 as needed to maintain the load.
• FIG. 4 is a block diagram illustrating amethod400 used to start-up a turbomachine, in accordance with an alternate embodiment of the present invention. The majority of the steps described inFIG. 3 may be repeated. Therefore, the discussion ofFIG. 4 will focus on the differences between themethods300 and400.Steps360 and365 of themethod300 are swapped in themethod400. Here, themethod400 prioritizes the step of increasing the temperature of the steam in theHP bowl125, instep460, over the step of increasing the temperature of the steam at theupstream location130. This approach in themethod400 is opposite to the approach used in themethod300; and may be used to further mitigate the rotor stress level.
• Embodiments of the present invention reduce the enthalpy of the steam upstream of theadmission valve115. In addition, the pressure ratio across theadmission valve115 may be reduced. Together, these actions may collectively reduce the temperature inside theHP bowl125. In an embodiment of the present invention, the temperature reduction across theadmission valve115 may range from approximately 125 deg. F. to approximately 150 deg. F. In comparison, the method described in conjunction withFIG. 2, may merely provide a temperate reduction of up to approximately 50 deg. F. The increased temperature reduction that may be provided by an embodiment of the present invention may reduce the steam-metal temperature mismatch and, thus mitigate rotor stress.
• FIG. 5 is achart500 illustrating operating curves in accordance withmethod300 ofFIG. 3 and 400 ofFIG. 4 in accordance with embodiments of the present invention. A first vertical axis represents Temperature (in deg. F.) and Pressure (in psia). A second vertical axis represents stress (in percentage). The first and second vertical axes are versus the start-up time (in minutes) on the horizontal axis.Data series505 represents the actual HP rotor stress anddata series510 represents the allowable stress limit.Data series515 and520 represent HP upstream pressure and temperature respectively. The upstream area may be adjacent the upstream location130 (illustrated inFIG. 1).Data series525 may represent the HP bowl temperature, illustrated asHP bowl125 inFIG. 1.
• FIG. 5 illustrates that throughout the start-up of thesteam turbine100, theHP rotor stress505 did not exceed theallowable stress limit510. Here, thebypass valve110 was modulated to increase the pressure at theupstream location130 to approximately 1400 psig. InFIG. 5 theHP bowl temperature525 is approximately 575 deg. F. In contrast, the HP bowl temperature ofFIG. 2 is approximately 725 deg. F.FIG. 5 also illustrates increases in the HP upstream pressure and temperature,520,525 respectively as theupstream pressure515 is decreased, as described.
• As one of ordinary skill in the art will appreciate, the many varying features and configurations described above in relation to the several exemplary embodiments may be further selectively applied to form the other possible embodiments of the present invention. Those in the art will further understand that all possible iterations of the present invention are not provided or discussed in detail, even though all combinations and possible embodiments embraced by the several claims below or otherwise are intended to be part of the instant application. In addition, from the above description of several exemplary embodiments of the invention, those skilled in the art will perceive improvements, changes, and modifications. Such improvements, changes, and modifications within the skill of the art are also intended to be covered by the appended claims. Further, it should be apparent that the foregoing relates only to the described embodiments of the present application and that numerous changes and modifications may be made herein without departing from the spirit and scope of the application as defined by the following claims and the equivalents thereof.

Claims (20)

1. A method of starting a powerplant machine, the method comprising:

providing a steam turbine configured for converting steam to a mechanical torque; wherein the steam turbine comprises an HP section; and

increasing a pressure of steam upstream of an admission valve to a pressure matching range, wherein the admission valve is located upstream of the HP section;

wherein the step of increasing the pressure of the steam decreases a temperature of the steam prior to admission into the HP section.

2. The method ofclaim 1 further comprising the step of initiating a start-up of the steam turbine if a start-up permissive is satisfied.

3. The method of claim further comprising the step of opening the admission valve to allow the steam to enter the HP section.

4. The method ofclaim 2 further comprising the step of determining whether a rotor stress is within an acceptable range.

5. The method ofclaim 4 further comprising the step of maintaining a current load on the steam turbine until the rotor stress is within the acceptable range.

6. The method ofclaim 5 further comprising the step of decreasing the pressure of the steam upstream of the admission valve.

7. The method ofclaim 6 further comprising the step of increasing a temperature of the steam in an HP bowl region of the HP section.

8. The method ofclaim 5 further comprising the step of increasing a temperature of the steam in an HP bowl region of the HP section.

9. The method ofclaim 8 further comprising the step of decreasing the pressure of the steam upstream of the admission valve.

10. A method of starting a powerplant comprising a steam turbine, the method comprising:

providing a steam turbine configured for converting steam to a mechanical torque; wherein the steam turbine comprises an HP section and a bypass system;

determining whether a cold start of the steam turbine is requested;

increasing a pressure the steam upstream of an admission valve to a pressure matching range, wherein the admission valve is located upstream of the HP section;

determining whether the steam upstream of the admission valve is within the pressure matching range;

initiating a start-up of the steam turbine if a start-up permissive is satisfied; and

modulating the admission valve such that allow the steam flows into the HP section;

wherein the step of increasing the pressure of the steam decreases a temperature of the steam before steams flows into the HP section.

11. The method ofclaim 10, wherein the step of increasing the pressure of the steam upstream of the admission valve to a pressure matching range, further comprises the step of modulating a bypass valve of the bypass system.

12. The method ofclaim 11 further comprising the step of determining whether a rotor stress is within an acceptable range.

13. The method ofclaim 12 further comprising the step of adjusting a loading rate of the steam turbine until the rotor stress is within the acceptable range.

14. The method ofclaim 13 further comprising the step of modulating the bypass valve to decrease the pressure of the steam upstream of the admission valve.

15. The method ofclaim 14 further comprising the step of increasing a temperature of the steam in an HP bowl region of the HP section.

16. The method ofclaim 13 further comprising the step of increasing a temperature of the steam in an HP bowl region of the HP section.

17. The method ofclaim 16 further comprising the step of modulating the bypass valve to decrease the pressure of the steam upstream of the admission valve.

18. A system configured for starting a steam turbine, the system comprising:

a steam turbine configured for converting steam to a mechanical torque;

wherein the steam turbine comprises an HP section; and

a control system configured for starting the steam turbine, wherein the control system performs the steps of:

determining whether a cold start of the steam turbine is requested;

increasing a pressure the steam upstream of an admission valve to a pressure matching range, before the steam flows into the HP section, wherein an admission valve is located upstream of the HP section;

determining whether the steam upstream of the admission valve is within the pressure matching range;

initiating a start-up of the steam turbine if a start-up permissive is satisfied; and

opening the admission valve to allow the steam to flow into the HP section;

wherein the step of increasing the pressure of the steam decreases a temperature of the steam prior to admission into the HP section.

19. The system ofclaim 18, wherein the control system performs the step of modulating a bypass valve of the bypass system to increase the pressure of the steam upstream of the admission valve.

20. The system ofclaim 19, wherein the control system further performs the steps of:

modulating the bypass valve to decrease the pressure of the steam upstream of the admission valve in order to increase a temperature of the steam in an HP bowl region of the HP section.

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