JP2014173481A - Steam turbine system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam turbine system capable of stably performing overload operation.SOLUTION: A main steam pipe is supplied with steam from a boiler and allows the supplied steam to flow therein. A main steam regulator valve is installed on the main steam pipe and regulates a flow rate of the steam flowing therein. An overload steam pipe, where a portion of the steam diverging from the steam flowing from the boiler in the main steam pipe flows into the overload steam pipe at an upstream side of the main steam pipe closer to the boiler than an installation position of the main steam regulator valve, allows the diverged steam to flow in the overload steam pipe. An overload valve is installed on the overload steam pipe and regulates the flow rate of the steam flowing therein. One end of a warming pipe is connected to a section downstream of the main steam pipe closer to the steam turbine than the installation position of the main steam regulator valve and the other end of the warming pipe is connected to the section downstream of the overload steam pipe closer to the steam turbine than the installation position of the overload valve.

Description

  Embodiments of the invention relate to a steam turbine system.

  In a steam turbine system of a thermal power plant, power is generated by generating steam by heat generated by burning fossil fuel and supplying the steam as a working fluid to drive the steam turbine.

  In the steam turbine system as described above, what performs “overload operation” exceeding the rated load in addition to “normal operation” below the rated load is known. In this steam turbine system, an overload steam pipe provided with an overload valve is installed in addition to a main steam pipe provided with a main steam control valve. When performing “overload operation”, the steam flowing through the main steam pipe is supplied to the first stage of the steam turbine via the main steam control valve, and the steam flowing through the main steam pipe bypasses the main steam control valve and is overheated. It flows into the load steam pipe and is supplied to the middle stage of the steam turbine through the overload valve (see, for example, Patent Documents 1 and 2).

JP 2006-161698 A JP 2010-14114 A

  In the steam turbine system, when the “overload operation” is performed, the overload valve that was fully closed during the “normal operation” is opened. For this reason, the portion of the overload steam pipe downstream from the position where the overload valve is installed has a large temperature difference from the high-temperature steam that has flowed in. is there.

  In addition, a hammer phenomenon may occur due to the large temperature difference. In addition, the steam may be cooled by a pipe and condensed (liquefied), and the condensed water may flow into the steam turbine.

  Due to such circumstances, in the above steam turbine system, it may be difficult to stably perform the overload operation.

  Therefore, the problem to be solved by the present invention is to provide a steam turbine system that can easily realize stable overload operation.

  The steam turbine system of the present embodiment includes a main steam pipe, a main steam control valve, an overload steam pipe, an overload valve, a steam turbine, and a warming pipe. The main steam pipe is supplied with steam from the boiler, and the supplied steam flows inside. The main steam control valve is installed in the main steam pipe, and adjusts the flow rate of the steam flowing through the main steam pipe. In the overload steam pipe, the steam that flows from the boiler through the main steam pipe branches and flows in the upstream part closer to the boiler than the position where the main steam control valve is installed in the main steam pipe. The inflowing steam flows inside. The overload valve is installed in the overload steam pipe and adjusts the flow rate of the steam flowing through the overload steam pipe. In the steam turbine, the steam flowing through the main steam pipe flows in as a working fluid from the first stage inlet via the main steam control valve, and the steam flowing through the overload steam pipe passes through the overload valve to the middle stage inlet. Flows in as working fluid. One end of the warming pipe is connected to the downstream side of the steam turbine from the position where the main steam control valve is installed in the main steam pipe, and the overload valve is installed in the overload steam pipe The other end is connected to a portion on the downstream side closer to the steam turbine than the formed position.

FIG. 1 is a system diagram schematically showing main parts of the steam turbine system according to the first embodiment. FIG. 2 is a system diagram schematically showing main parts of the steam turbine system according to the first embodiment. FIG. 3 is a system diagram schematically showing a main part of the steam turbine system according to the second embodiment.

  Embodiments will be described with reference to the drawings.

<First Embodiment>
[A] Configuration FIGS. 1 and 2 are system diagrams schematically showing the steam turbine system according to the first embodiment.

  In FIG. 1, the fluid that flows when performing “normal operation” of a rated load or less in the steam turbine system is also indicated by arrows. In FIG. 2, the fluid that flows when performing “overload operation” exceeding the rated load in the steam turbine system is also shown by arrows. In FIGS. 1 and 2, a part where a part of the symbol of the valve is filled indicates that the opening degree of the valve is fully closed.

  The steam turbine system is installed in a thermal power plant, and includes a boiler 11, a steam turbine 21, a condenser 31, and a pump 41 as shown in FIGS. In the steam turbine system, a main steam pipe P11A (main steam reed pipe), an overload steam pipe P12, a warming pipe P13, a low temperature reheat steam pipe P21A, a high temperature reheat steam pipe P11B, A water pipe P31 and a water supply pipe P41 are provided.

  The main part which comprises the steam turbine system of this embodiment is demonstrated in detail.

[A-1] Steam turbine 21
In the steam turbine system, the steam turbine 21 includes a first turbine 21A (high pressure turbine) and a second turbine 21B (intermediate pressure turbine).

  In each of the first turbine 21A and the second turbine 21B, a turbine rotor (not shown) is accommodated in a casing (not shown). Each of the first turbine 21A and the second turbine 21B is a multi-stage axial flow turbine, and a turbine stage composed of stationary blades (not shown) and moving blades (not shown) rotates the turbine rotor. A plurality of stages are provided along the axis. Then, the steam that has flowed into the casing as a working medium expands and performs work in each turbine stage, whereby the turbine rotor rotates.

  Between the first turbine 21 </ b> A and the second turbine 21 </ b> B, the turbine rotors are coaxial and connected to each other, and the turbine rotor is connected to the rotating shaft of the generator 22. For this reason, the generator 22 is driven by the rotation of the turbine rotor to generate power.

  In each of the first turbine 21A and the second turbine 21B, the steam that has flowed in as the working medium decreases in pressure and temperature as it flows from one end side to the other end side, and is the final stage turbine stage located on the other end side. After passing through, it is discharged from the exit.

  Although details will be described later, in this embodiment, the steam turbine 21 is a reheat turbine, and after the steam F21A discharged from the first turbine 21A is reheated, the reheated steam F11B is 2 flows into the turbine 21B.

[A-2] Main steam pipe P11A
One end of the main steam pipe P11A is connected to the outlet of the heating unit (heater) of the boiler 11. At the same time, the other end of the main steam pipe P11A is connected to the inlet located at the first stage in the first turbine 21A.

  The main steam pipe P11A is provided with a main steam stop valve V11a (MSV) and a main steam control valve V11b (CV).

[A-3] Overload steam pipe P12
One end of the overload steam pipe P12 is connected to the upstream portion P111 closer to the boiler 11 than the position where the main steam control valve V11b is installed in the main steam pipe P11A. At the same time, the other end of the overload steam pipe P12 is connected to the inlet located in the middle stage in the first turbine 21A.

  An overload valve V12 is provided in the overload steam pipe P12.

[A-4] Warming tube P13
One end of the warming pipe P13 is connected to a portion P112 on the downstream side closer to the first turbine 21A than the position where the main steam control valve V11b is installed in the main steam pipe P11A. At the same time, the other end of the warming pipe P13 is connected to a portion P122 (overload valve downstream piping) closer to the first turbine 21A than the position where the overload valve V12 is installed in the overload steam pipe P12. ing.

  Here, the other end of the warming pipe P13 is installed in a portion close to the overload valve V12 in the downstream portion P122 of the overload steam pipe P12.

  A flow rate adjustment unit V13 is installed in the warming pipe P13.

  The flow rate adjusting unit V13 is, for example, an orifice and restricts the flow path to be narrower than other portions so that the steam F13 (warming steam) flowing through the warming pipe P13 is less likely to flow.

  The flow rate adjusting unit V13 may be configured by using a valve in addition to the orifice. In this case, the flow F13 (warming steam) flowing through the warming pipe P13 is adjusted by adjusting the opening of the valve. ) Adjust the flow rate.

[A-5] Other detailed configuration One end of the low-temperature reheat steam pipe P21A is connected to the outlet of the first turbine F21A, and the other end is connected to the inlet of the reheat section (reheater) provided in the boiler 11. Has been. One end of the high-temperature reheat steam pipe P11B is connected to the outlet of the reheat section provided in the boiler 11, and the other end is connected to the inlet of the second turbine 21B. The condensate pipe P31 has one end connected to the outlet of the condenser 31 and the other end connected to the inlet of the pump 41. One end of the water supply pipe P41 is connected to the outlet of the pump 41, and the other end is connected to the inlet of the heating unit (heater) of the boiler 11.

[B] Operation The main operation when the steam turbine system is operated will be described.

  Here, the description will be made separately for the case of performing “normal operation” below the rated load and the case of performing “overload operation” exceeding the rated load.

  When operating in the steam turbine system, the opening degree of each valve is adjusted in accordance with the opening degree command output from the control unit (regulator) (not shown) of the steam turbine system. .

[B-1] “Normal Operation” As shown in FIG. 1, when performing “normal operation” below the rated load, the overload valve V12 is fully closed. Then, with the main steam stop valve V11a fully opened, the opening degree of the main steam control valve V11b is adjusted according to the load.

  Specifically, in the “normal operation”, the steam F11A (main steam) flows from the boiler 11 into the main steam pipe P11A and flows inside the main steam pipe P11A. The steam F11A (main steam) enters the inlet located at the first stage in the first turbine 21A through the main steam stop valve V11a and the main steam control valve V11b in sequence. Here, after the steam F11A (main steam) passes through the main steam stop valve V11a, the flow rate is adjusted by the main steam control valve V11b, and flows into the first turbine 21A as a working medium.

  At this time, a part of the steam F11A (main steam) branches after passing through the main steam stop valve V11a in the main steam pipe P11A and before passing through the main steam control valve V11b, and the overload steam pipe P12 is reached. Flow into. In “normal operation”, since the overload valve V12 is fully closed, the flow of the steam F12 flowing into the overload steam pipe P12 is stopped by the overload valve V12. That is, the steam F12 flowing into the overload steam pipe P12 flows through the portion P121 (overload valve upstream pipe) upstream of the position where the overload valve V12 is installed in the overload steam pipe P12. The portion P122 (overload valve downstream piping) on the downstream side of the position where V12 is installed does not flow.

  In addition, the steam F11A (main steam) branches sequentially after passing through the main steam stop valve V11a and the main steam control valve V11b in the main steam pipe P11A, and flows into the warming pipe P13.

  The steam F13 (warming steam) that has flowed into the warming pipe P13 flows to a portion P122 (overload valve downstream pipe) downstream of the position where the overload valve V12 is installed in the overload steam pipe P12. Here, the flow rate of the steam F13 (warming steam) flowing through the warming pipe P13 is adjusted by the flow rate adjusting unit V13, and flows out to the downstream portion P122 (overload valve downstream pipe) of the overload steam pipe P12. .

  The steam F13 (warming steam) flows in the downstream portion P122 (overload valve downstream piping) of the overload steam pipe P12, so that the downstream portion P122 (overload valve downstream piping) of the overload steam pipe P12. Is warmed up. Thereafter, the steam F13 (warming steam) enters the inlet located in the middle stage in the first turbine 21A from the downstream portion P122 (overload valve downstream piping) of the overload steam pipe P12.

  The steams F11A and F13 that have flowed into the first turbine 21A are discharged from the outlet after being expanded by the first turbine 21A and performing work. The steam F21A (exhaust steam) discharged from the outlet of the first turbine 21A flows into the reheat part (reheater) of the boiler 11 through the low-temperature reheat steam pipe P21A and is reheated. Thereafter, the reheated steam F11B (reheated steam) flows as an operating medium into the inlet of the second turbine 21B via the high-temperature reheated steam pipe P11B.

  The steam F11B (reheated steam) flowing into the second turbine 21B expands in the second turbine 21B and performs work, and is then discharged from the outlet. The steam F21B (exhaust steam) discharged from the outlet of the second turbine 21B flows into the condenser 31, and is then cooled and condensed (condensed) in the condenser 31. And the condensed water F31 (condensate) flows into the pump 41, and is pressurized and transferred by the pump 41. And the condensed water F41 (water supply) transferred with the pump 41 flows into the boiler 11, and is heated by the heating part (heater) of the boiler 11. Then, the steam F11A generated by the heating flows into the first turbine 21A as the working medium as described above.

[B-2] “Overload operation” As shown in FIG. 2, when performing “overload operation” exceeding the rated load, the opening degree of the main steam stop valve V11a and the main steam control valve V11b is fully opened. To. In this state, the opening of the overload valve V12 is adjusted from fully closed to an opening corresponding to the load.

  Specifically, in the “overload operation”, similarly to the “normal operation”, the steam F11A (main steam) generated in the boiler 11 sequentially passes through the main steam stop valve V11a and the main steam control valve V11b. And flows through the main steam pipe P11A. Then, the steam F11A (main steam) flows as an operating medium into the inlet located at the first stage in the first turbine 21A.

  At this time, a part of the steam F11A (main steam) is branched after passing through the main steam stop valve V11a in the main steam pipe P11A and before flowing into the main steam control valve V11b, and the overload steam pipe P12. Flow into. As described above, during the “overload operation”, unlike the “normal operation”, the overload valve V12 is not fully closed but is adjusted to an opening degree corresponding to the load. For this reason, the flow of the steam F12 (overload steam) that has branched and flowed into the overload steam pipe P12 is adjusted by adjusting the opening of the overload valve V12, and the inlet located in the middle stage in the first turbine 21A. Into the working medium. That is, the steam F12 flowing into the overload steam pipe P12 flows through the portion P121 (overload valve upstream pipe) upstream of the position where the overload valve V12 is installed in the overload steam pipe P12, and then overloads. It flows through a portion P122 (overload valve downstream piping) on the downstream side of the position where the valve V12 is installed.

  Similarly to the “normal operation”, the first turbine 21A is driven by the steams F11A and F12 flowing into the first turbine 21A, and the second turbine 21B is driven by the steam F11B flowing into the second turbine 21B. Power generation.

  Before performing the “overload operation”, the downstream portion of the overload steam pipe P12 is caused by the steam F13 (warming steam (bypass main steam)) flowing through the warming pipe P13 during the “normal operation” described above. P122 is warmed. Then, after the portion P122 (overload valve downstream piping) on the downstream side of the overload steam pipe P12 is warmed, the “overload operation” is performed as described above.

  For this reason, when performing the “overload operation” in the present embodiment, the steam flowing into the portion P122 (overload valve downstream piping) on the downstream side of the overload steam pipe P12 and the portion P122 (overload valve downstream piping). The temperature difference from F12 (overload steam) is reduced.

[C] Summary As described above, the warming pipe P13 is provided in the steam turbine system of the present embodiment. In this embodiment, during the “normal operation” before performing the “overload operation”, the downstream portion P122 (overload valve downstream pipe) of the overload steam pipe P12 is moved from the main steam pipe P11A to the warp. Warming is performed by steam F13 (warming steam) flowing through the ming pipe P13.

  For this reason, in the present embodiment, as described above, during the “overload operation”, the portion P122 (overload valve downstream piping) on the downstream side of the overload steam pipe P12 and the steam flowing into the portion P122. The temperature difference with F12 (overload steam) is reduced.

  And in connection with this, since it can suppress that a big thermal stress is added to the part P122 (overload valve downstream piping), damage can be prevented effectively. Moreover, the occurrence of the hammer phenomenon can be prevented by reducing the temperature difference. Furthermore, since it can suppress that the vapor | steam F12 is cooled and condensed in the part P122 (overload valve downstream piping), it can prevent that condensed water flows in into the 1st turbine 21A.

  Therefore, in the steam turbine system of the present embodiment, it is possible to easily realize “overload operation” stably.

  Moreover, in this embodiment, the flow volume adjustment part V13 is installed in the warming pipe | tube P13. The flow rate adjusting unit V13 restricts and adjusts the flow rate of the steam F13 (warming steam) branched from the main steam pipe P11A and flowing through the warming pipe P13. For this reason, in this embodiment, the fall of power generation efficiency can be prevented.

  In the present embodiment, the warming pipe P13 is connected to the overload valve V12 in the portion P122 (overload valve downstream pipe) on the downstream side of the position where the overload valve V12 is installed in the overload steam pipe P12. It is installed in a close part. For this reason, in this embodiment, the downstream part P122 (overload valve downstream piping) of the overload steam pipe P12 can be warmed effectively. In particular, it is preferable to connect the warming pipe P13 to the overload steam pipe P12 in the vicinity of the outlet of the overload valve V12.

[D] Modified Example As described above, in the present embodiment, the steam turbine 21 includes the first turbine 21A and the second turbine 21B and is configured by two vehicle compartments, but is not limited thereto. It may be composed of a single compartment, or may be composed of three or more compartments. In addition, the steam turbine 21 may have various types.

Second Embodiment
[A] Configuration FIG. 3 is a system diagram schematically showing main parts of a steam turbine system according to the second embodiment.

  In FIG. 3, the fluid that flows during “turbine warming” of the steam turbine system is also indicated by a one-dot chain line arrow.

  In the present embodiment, as shown in FIG. 3, an auxiliary steam system 51 and a drain pipe P113 are provided. The present embodiment is the same as the first embodiment except for this point and related points. For this reason, in this embodiment, the description which overlaps with this embodiment is abbreviate | omitted suitably.

[A-1] Auxiliary steam system 51
As shown in FIG. 3, the auxiliary steam system 51 is provided with a pipe P51 between the low-temperature reheat steam pipe P21A, and one end of the pipe P51 is connected to the auxiliary steam system 51. The end is connected to the middle of the low temperature reheat steam pipe P21A.

[A-2] Drain pipe P113
The drain pipe P113 is, for example, a post-valve drain pipe of the main steam control valve V11b. As shown in FIG. 3, the drain pipe P113 is provided with a drain valve V113 (post-valve drain valve).

  In addition, the drain pipe P113 may be branched from the main steam pipe P11A and installed other than the post-valve drain pipe of the main steam control valve V11b. In this case, one end of the drain pipe P113 is connected to a part P112 (overload valve downstream pipe) downstream of the installation position of the main steam control valve V11b in the main steam pipe P11A. Here, the drain pipe P113 has one end at a position closer to the main steam control valve V11b than a position where the warming pipe P13 is connected in a portion P112 (overload valve downstream pipe) on the downstream side of the main steam pipe P11A. They are connected (see FIG. 3).

[B] Operation The main operation when the steam turbine system is operated will be described.

  Here, the operation at the time of “turbine warming” will be described. That is, the operation in the warming (starting) stage before performing load operation such as “normal operation” and “overload operation” will be described.

  In “turbine warming”, the steam S51 (turbine warming steam) discharged from the auxiliary steam system 51 passes through the pipe P51 and the low-temperature reheat steam pipe P21A sequentially from the outlet of the first turbine 21A. To supply. Thereby, warming is performed about the 1st turbine 21A.

  At this time, the steam S51 (turbine warming steam) that flows into the first turbine 21A from the auxiliary steam system 51 flows out from the first-stage inlet to the main steam pipe P11A in the first turbine 21A, and flows back through the main steam pipe P11A. That is, the steam S51 (turbine warming steam) is in a direction opposite to the steam F11A (main steam) (see FIG. 1 and the like) that flows from the boiler 11 to the first turbine 21A during an operation such as “normal operation”. Toward the main steam pipe P11A. The main steam pipe P11A is warmed by the steam S21a that flows back through the main steam pipe P11A.

  At the same time, the steam S51 (turbine warming steam) supplied from the auxiliary steam system 51 to the first turbine 21A flows out from the middle inlet in the first turbine 21A and flows back through the overload steam pipe P12. Warming is performed on the portion P122 on the downstream side of the overload steam pipe P12 by the steam S21b flowing backward through the overload steam pipe P12.

  In addition, as shown in FIG. 3, during the “turbine warming”, the overload valve V <b> 12 is opened. For example, the overload valve V12 is fully opened. For this reason, the steam S21b that flows back through the overload steam pipe P12 flows from the portion P122 (overload valve downstream pipe) located downstream in the overload steam pipe P12 via the overload valve V12 to the overload steam pipe P12. Flows in a portion P121 (overload valve upstream piping) located upstream. As a result, warming is performed on the overload valve V12 and the upstream portion P121 of the overload steam pipe P12 by the steam S21b (turbine warming steam) that flows back through the overload steam pipe P12.

  In addition, when the steam S21b flowing backward through the overload steam pipe P12 warms the portion P122 on the downstream side of the overload steam pipe P12 during “turbine warming”, the steam S21b is cooled and condensed. Drain S13 (drain water) is generated. The drain S13 flows into the drain pipe P113 through the warming pipe P13 and the main steam pipe P11A. Then, the drain S13 that has flowed into the drain pipe P113 is discharged to the outside from the drain pipe P113 via the drain valve V113.

[C] Summary As described above, the steam turbine system of the present embodiment is provided with the auxiliary steam system 51. The auxiliary steam system 51 warms the first turbine 21A by supplying steam S51 (turbine warming steam) from the outlet of the first turbine 21A to the inside during “turbine warming”.

  The steam S51 (turbine warming steam) flows back through the main steam pipe P11A from the first stage inlet in the first turbine 21A and warms the main steam pipe P11A. At the same time, the steam S51 (turbine warming steam) flows back through the overload steam pipe P12 from the middle inlet in the first turbine 21A, and the downstream portion P122 (overload valve downstream piping) of the overload steam pipe P12. Warm). Further, in the present embodiment, the “overload valve V12” is opened during “turbine warming”. For this reason, each of the overload valve V12 and the upstream portion P121 (overload valve upstream pipe) of the overload steam pipe P12 is warmed by the steam S21b that flows back through the overload steam pipe P12.

  And in this embodiment, after each part is warmed at the time of “turbine warming”, operations such as “normal operation” and “overload operation” are performed to generate power.

  For this reason, in this embodiment, when performing operations such as “normal operation” and “overload operation”, there is a temperature difference between each part warmed as described above and the steam flowing into each part. Reduced.

  As a result, since it can suppress that a big thermal stress is added to each part, damage can be prevented effectively. Moreover, the occurrence of the hammer phenomenon can be prevented by reducing the temperature difference. Furthermore, since it can suppress that a vapor | steam is cooled and condensed in each part, the condensed water can be prevented from flowing into the first turbine 21A.

  In addition, a drain pipe P113 is installed in the steam turbine system of the present embodiment. As described above, the drain pipe P113 is formed so that the drain S13 generated when warming the portion P122 on the downstream side of the overload steam pipe P12 during the “turbine warming” is connected to the warming pipe P13 and the main steam pipe P11A. The drain S13 that has flowed in is discharged to the outside. For this reason, in this embodiment, drain S13 can be prevented from flowing into the first turbine 21A. Moreover, since drain S13 can be discharged | emitted by the existing installation, the addition of an apparatus is unnecessary and it can suppress the increase in installation cost.

<Others>
Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 11 ... Boiler, 21 ... Steam turbine, 21A ... 1st turbine, 21B ... 2nd turbine, 22 ... Generator, 31 ... Condenser, 41 ... Pump, 51 ... Auxiliary steam system, P113 ... Drain pipe, P11A ... Main Steam pipe, P11B ... High temperature reheat steam pipe, P12 ... Overload steam pipe, P13 ... Warming pipe, V11b ... Main steam control valve, V12 ... Overload valve, V13 ... Flow rate adjuster

Claims (7)

Steam is supplied from the boiler, and the supplied steam flows through the main steam pipe,
A main steam control valve that is installed in the main steam pipe and adjusts the flow rate of the steam flowing through the main steam pipe;
In the upstream portion closer to the boiler than the position where the main steam control valve is installed in the main steam pipe, the steam flowing through the main steam pipe branches from the boiler and flows in. An overloaded steam pipe through which the steam flows
An overload valve which is installed in the overload steam pipe and adjusts the flow rate of the steam flowing through the overload steam pipe;
The steam flowing through the main steam pipe flows as a working fluid from the first stage inlet through the main steam control valve, and the steam flowing through the overload steam pipe passes through the overload valve to the middle stage inlet. A steam turbine flowing in as a working fluid from
One end of the main steam pipe is connected to the downstream side closer to the steam turbine than the position where the main steam control valve is installed, and the overload valve is installed in the overload steam pipe. And a warming pipe having the other end connected to a downstream portion closer to the steam turbine than the position where the steam turbine is provided. Before the overload operation exceeding the rated load is performed, a portion of the overload steam pipe closer to the steam turbine than the position where the overload valve is installed is connected from the main steam pipe to the warming pipe. Warmed by steam flowing through,
The steam turbine system according to claim 1. A flow rate adjusting unit for adjusting the flow rate of the steam flowing through the warming pipe is installed in the warming pipe.
The steam turbine system according to claim 1 or 2. The warming pipe is installed in a portion near the overload valve in a portion on the downstream side closer to the steam turbine than a position where the overload valve is installed in the overload steam pipe.
The steam turbine system according to any one of claims 1 to 3. An auxiliary steam system for warming the steam turbine by supplying steam to the inside from the outlet of the steam turbine during turbine warming;
The steam supplied from the auxiliary steam system to the steam turbine during the turbine warming warms the main steam pipe by flowing back the main steam pipe from the first stage inlet in the steam turbine, and in the steam turbine Warming a portion of the overload steam pipe closer to the steam turbine than the position where the overload valve is installed in the overload steam pipe by backflowing the overload steam pipe from a middle inlet,
The steam turbine system according to any one of claims 1 to 4. The overload valve is opened during the turbine warming,
Each of the overload valve and the upstream portion of the overload steam pipe closer to the boiler than the position where the overload valve is installed is warmed by the steam flowing back through the overload steam pipe. The
The steam turbine system according to claim 5. During the turbine warming, the drain that is generated when warming the downstream portion of the overload steam pipe closer to the steam turbine than the position where the overload valve is installed is the warming pipe and the main steam. A drain pipe that flows in through the pipe and discharges the drained drain to the outside.
The steam turbine system according to claim 5 or 6.

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