JP7120839B2 - STEAM TURBINE PLANT AND START-UP METHOD THEREOF - Google Patents

Description

The present invention relates to a steam turbine plant comprising a boiler, a steam turbine driven by steam from the boiler, and a condenser for returning the steam exhausted from the steam turbine to water, and a start-up method thereof.

A steam turbine plant comprises a boiler, a steam turbine driven by steam from the boiler, and a condenser for converting the steam exhausted from the steam turbine back to water. Steam turbine plants may also include gas turbines. In this case, the aforementioned boiler is an exhaust heat recovery boiler that generates steam with the heat of the exhaust gas discharged from the gas turbine. Such steam turbine plants are commonly referred to as combined cycle plants.

In a combined cycle plant, steam is not generated from the heat recovery steam generator before the gas turbine is started. For this reason, when steam is required during the start-up process of the plant, an auxiliary boiler may be provided in addition to the heat recovery boiler.

Providing an auxiliary boiler increases the equipment cost of the combined cycle plant. For this reason, Patent Document 1 below discloses a technique for avoiding dependency on steam from an auxiliary boiler in the plant start-up process.

JP-A-11-022419

The following methods are conceivable as a method of starting the plant without using the auxiliary boiler.

First, the gas turbine is started, and the heat of the exhaust gas from the gas turbine is used to generate steam from the heat recovery boiler. When steam begins to be generated from the heat recovery boiler, part of this steam is supplied to the shaft seal portion of the steam turbine, and this steam seals the gap between the turbine rotor and the casing covering it. Next, after the inside of the condenser casing is sucked to increase the degree of vacuum inside the condenser casing, the steam from the heat recovery boiler is supplied to the steam turbine to drive the steam turbine. If there is an auxiliary boiler, steam can be supplied to the shaft seal portion of the steam turbine before the gas turbine is started, and this steam can seal the gap between the turbine rotor and the casing. Therefore, if there is an auxiliary boiler, the inside of the condenser casing can be sucked before the gas turbine is started.

Suppose that after the gas turbine is started and before the inside of the condenser casing is sucked in, gas-phase or liquid-phase high-temperature fluid (water or steam) is generated, and it becomes necessary to cool this high-temperature fluid. . In this case, it is not preferable to introduce the high-temperature fluid into the condenser casing and cool the high-temperature fluid with the condenser for the following reasons, so the high-temperature fluid is discharged outside the system.

When the inside of the condenser casing is not sucked, the heat transfer coefficient between the medium to be cooled and the heat transfer tubes inside the condenser casing is low. For this reason, in this state, the heat exchange efficiency between the gas-phase or liquid-phase high-temperature fluid and the cooling medium in the heat transfer tubes is low, and the gas-phase or liquid-phase high-temperature fluid cannot be efficiently cooled. As a result, the temperature inside the condenser casing rises, and the time required to increase the degree of vacuum inside the condenser casing becomes longer. Further, when the liquid-phase high-temperature fluid flows into the condenser casing, part of the liquid-phase high-temperature fluid flashes and becomes steam. When the inside of the condenser casing is not sucked, as described above, the heat exchange efficiency between the high-temperature fluid in the gas or liquid phase and the cooling medium in the heat transfer tubes is low. Gas phase water cannot be efficiently converted to liquid phase water. As a result, the pressure inside the condenser casing increases, and the rupture disk that protects the condenser casing or the steam turbine casing may be damaged.

Again, for the above reasons, when it becomes necessary to cool the high-temperature fluid in the gas or liquid phase before sucking it into the condenser casing, the high-temperature fluid is discharged outside the system. . For this reason, a discharge device such as a flush pipe or a silencer is required to discharge the high-temperature fluid to the outside of the system, which raises the problem of increased equipment costs.

Therefore, the present invention avoids discharging the high-temperature fluid to the outside of the system even when it becomes necessary to cool the high-temperature fluid in the gas or liquid phase before sucking it into the condenser casing, thereby reducing the facility cost. It is an object of the present invention to provide a steam turbine plant and a method for starting the same that can suppress the

A steam turbine plant according to an aspect of the invention for solving the above problems includes:
A boiler that generates steam, a steam turbine that is driven by the steam from the boiler, a main steam valve that adjusts the flow rate of steam flowing from the boiler to the steam turbine, and heat exchange with the steam exhausted from the steam turbine. a plurality of heat transfer tubes through which a cooling medium flows, a condenser casing covering the plurality of heat transfer tubes, a condenser for returning the steam to water, a makeup water tank for storing makeup water, and the makeup A make-up water control valve for adjusting the flow rate of make-up water supplied from a water tank into the condenser casing, a vacuum pump for sucking the inside of the condenser casing, and saturation under the environment inside the condenser casing. A hot fluid line that guides a hot fluid having a temperature higher than the temperature into the condenser, a hot fluid control valve that adjusts the flow rate of the hot fluid flowing through the hot fluid line, and a control device. The control device sends an open instruction to the high-temperature fluid control valve to cause the high-temperature fluid to flow into the condenser casing from the high-temperature fluid line; a suction step of sending a drive instruction to a pump to suck the inside of the condenser casing; and after the suction step, sending an opening instruction to the main steam valve to supply steam from the boiler to the steam turbine. By adjusting the opening degree of the make-up water control valve before the steam turbine start-up process, the high-temperature fluid supply process, the suction process, and the steam turbine start-up process, the water accumulated in the condenser casing is removed. a water-heat transfer tube contacting step of controlling the amount of water accumulated in the condenser casing to contact at least some of the plurality of heat transfer tubes through which the cooling medium flows; Run.

In this aspect, the water-heat transfer tube contacting step is performed before the hot fluid supplying step, the suction step and the steam turbine starting step. When the water-heat transfer tube contact step is performed, at least some of the heat transfer tubes in which the cooling medium is flowing and the water (hereinafter referred to as condensate) accumulated in the condenser casing is in contact with The heat transfer coefficient between the liquid-phase medium to be cooled and the heat transfer tubes is much higher than the heat transfer rate between the gas-phase medium to be cooled and the heat transfer tubes. Therefore, in at least some of the heat transfer tubes, the heat exchange efficiency between the condensate containing the high-temperature fluid and the cooling medium in the heat transfer tubes is increased.

Therefore, in this aspect, even if the high-temperature fluid is caused to flow into the condenser casing, the high-temperature fluid can be effectively cooled. Therefore, in this aspect, even if the high-temperature fluid is allowed to flow into the condenser casing, it is possible to suppress the temperature rise in the condenser casing and the temperature rise of the condensate containing the high-temperature fluid. Furthermore, in this aspect, the pressure rise in the condenser casing can be suppressed.

Here, in the steam turbine plant of the aspect, the control device may cause the water accumulated in the condenser casing to come into contact with all of the plurality of heat transfer tubes in the water-heat transfer tube contact step. good.

In this aspect, the high-temperature fluid can be cooled more effectively than when some of the plurality of heat transfer tubes through which the cooling medium flows are in contact with the condensate.

Further, in the steam turbine plant of any one of the above aspects, the control device, in the water-heat transfer tube contact step, adjusts the water level of the water accumulated in the condenser casing to The water level in the condenser casing may be brought into contact with the at least part of the heat transfer tubes by raising the level of the water in the condenser casing to be higher than the level of the water accumulated in the condenser casing.

In the steam turbine plant of any one of the above aspects, a drainage facility for receiving water accumulated in the condenser casing, a drainage line for guiding water accumulated in the condenser casing to the drainage facility, and a drain valve for regulating the flow of water through the drain line. In this case, when the pressure in the condenser casing drops below a predetermined pressure during the execution of the suction process, the control device adjusts the opening degree of the drain valve so that the condenser By controlling the amount of water accumulated in the casing, the water accumulated in the condenser casing is kept in non-contact with at least some of the plurality of heat transfer tubes through which the cooling medium flows. Water-heat transfer tube non-contact process is carried out.

When the inside of the condenser casing is sucked, the heat transfer coefficient between the medium to be cooled such as steam and the heat transfer tubes is higher than when the inside of the condenser casing is not sucked. Therefore, in this state, the heat exchange rate between the medium to be cooled and the cooling medium in the heat transfer tubes is high. Further, if a portion of the heat transfer tubes are in contact with the condensate in the condenser casing, as described above, the heat exchange rate between the condensate and the cooling medium in the portion of the heat transfer tubes increases. . Therefore, in a state where the inside of the condenser casing is sucked, the medium to be cooled is excessively cooled, and the temperature of the condensate, which is the result of cooling the medium to be cooled, drops. As the temperature of the condensate drops, the temperature of the feed water supplied to the boiler drops, increasing the thermal energy required to turn this feed water into steam. That is, when the temperature of the condensate drops, the efficiency of steam generation in the boiler drops. Therefore, in this aspect, after the inside of the condenser casing starts to be sucked, at least some of the heat transfer tubes are kept out of contact with the condensate, thereby suppressing the temperature drop of the condensate.

A steam turbine plant according to another aspect of the invention for solving the above problems includes:
A boiler that generates steam, a steam turbine that is driven by the steam from the boiler, a main steam valve that adjusts the flow rate of steam flowing from the boiler to the steam turbine, and heat exchange with the steam exhausted from the steam turbine. a plurality of heat transfer tubes through which a cooling medium flows, a condenser casing covering the plurality of heat transfer tubes, the condenser returning the steam to water, and some of the plurality of heat transfer tubes a switching device for switching a medium supply state between a first state in which the cooling medium is sent to and a second state in which the cooling medium is not sent to the part of the heat transfer tubes; a vacuum pump, a high-temperature fluid line for guiding into the condenser a high-temperature fluid having a temperature higher than the saturation temperature in the environment in the condenser casing, and a flow rate of the high-temperature fluid flowing through the high-temperature fluid line. A regulating hot fluid control valve and a controller. The control device sends an open instruction to the high-temperature fluid control valve to cause the high-temperature fluid to flow into the condenser casing from the high-temperature fluid line; a suction step of sending a drive instruction to a pump to suck the inside of the condenser casing; and after the suction step, sending an opening instruction to the main steam valve to supply steam from the boiler to the steam turbine. before the steam turbine start-up step, the high-temperature fluid supply step, the suction step, and the steam turbine start-up step, an instruction is sent to the switch to enter the first state, and the condenser casing is a water-heat-transfer-tube contacting step of contacting the part of the heat transfer tubes through which the cooling medium flows with the water accumulated in the cooling medium.

In this aspect, as in the above-described one aspect, a water-heat transfer tube contacting step is performed in which condensate is brought into contact with some of the plurality of heat transfer tubes in which the cooling medium is flowing. Therefore, in some heat transfer tubes, the heat exchange rate between the condensate containing the high-temperature fluid and the cooling medium in the heat transfer tubes increases. Therefore, in this aspect, even if the high-temperature fluid is allowed to flow into the condenser casing, the high-temperature fluid can be effectively cooled as in the above-described one aspect.

In the steam turbine plant of the aspect including the switching machine, the second state is not sending the cooling medium to the part of the heat transfer tubes among the plurality of heat transfer tubes and sending the cooling medium to the other heat transfer tubes. state. The other heat transfer tubes are positioned higher than the part of the heat transfer tubes among the plurality of heat transfer tubes, and remain in the condenser casing when the steam turbine is in rated operation. It is a heat transfer tube that does not submerge in water. Some of the heat transfer tubes are submerged in water that has accumulated in the condenser casing when the steam turbine is in rated operation.

In the steam turbine plant of the above aspect, in which the cooling medium is sent to the other heat transfer tubes in the second state, the control device controls that the pressure in the condenser casing is equal to or lower than a predetermined pressure in the execution of the suction step. , the switching device is instructed to enter the second state, and the water accumulated in the condenser casing is made non-contact with the other heat transfer pipe through which the cooling medium flows. A water-tube non-contact process may be performed.

In this aspect, as in the above-described aspect in which the water-heat transfer tube non-contact step is performed, when the pressure in the condenser casing drops below a predetermined pressure in the execution of the suction step, the condenser casing A water-heat-transfer-tube non-contact process is performed to make contact between the water accumulated inside and some of the heat-transfer tubes through which the cooling medium flows. Therefore, in this aspect, similarly to the above-described aspect in which the water-heat transfer tube non-contact step is performed, it is possible to suppress the temperature drop of the condensate (feed water) sent to the boiler.

Further, in the steam turbine plant of any one of the aspects described above, the steam turbine includes a steam turbine rotor that rotates about an axis, a steam turbine casing that covers the steam turbine rotor, and a steam turbine rotor that uses steam to rotate the steam turbine rotor. and a shaft seal device for sealing a gap between the end of the steam turbine casing and the steam turbine casing. In this case, the steam turbine plant further includes a seal steam line that guides part of the steam generated from the boiler to the shaft seal device, and a seal steam valve that adjusts the flow rate of the steam flowing through the seal steam line. . Further, the control device sends an opening instruction to the sealing steam valve to perform a shaft sealing step of supplying steam to the shaft sealing device before performing the suction step.

Further, in the steam turbine plant of any of the above aspects, the condenser has a water sprayer that sprays water from a position within the condenser casing above the plurality of heat transfer tubes. may In this case, the control device executes a water spraying step of spraying water from the water sprayer during the high-temperature fluid supplying step.

When water is sprayed from a position above the heat transfer tubes, the high-temperature fluid exchanges heat with the cooling medium in the heat transfer tubes and also with the sprayed water. Therefore, the high-temperature fluid can be cooled more effectively by executing the water spray process.

In the steam turbine plant according to any one of the above aspects, a compressor that compresses air, a combustor that burns fuel in the air compressed by the compressor to generate combustion gas, and a combustor that is driven by the combustion gas a gas turbine having a turbine; a fuel valve for adjusting the flow rate of fuel supplied to the combustor; a bleed line for bleeding a portion of the air compressed by the compressor; a cooling water line through which a portion of water flows; an air cooler for exchanging heat between air from the bleed line and water from the cooling water line to cool the air and heat the water; and a cooling air line for directing the air cooled by the air cooler to hot components in contact with the combustion gases in the gas turbine. In this case, the boiler is an exhaust heat recovery boiler that generates steam from the heat of the exhaust gas discharged from the gas turbine. Also, the high-temperature fluid line is a line that allows the water heated by the air cooler to flow into the condenser casing as the high-temperature fluid. Also, the high-temperature fluid control valve is a control valve for adjusting the flow rate of water flowing through the cooling water line or water flowing through the high-temperature fluid line.

In this aspect, the high-temperature fluid, which is water heated by the air cooler, can be effectively cooled by the condenser before the inside of the condenser casing is sucked.

In the steam turbine plant according to any one of the above aspects, which includes the gas turbine, the control device instructs the fuel valve to open after the water-heat transfer tube contact step and before the suction step. to perform a gas turbine start-up step to initiate delivery of the fuel to the combustor.

A start-up method for a steam turbine plant according to one aspect of the invention for solving the above problems includes:
a boiler that generates steam, a steam turbine that is driven by the steam from the boiler, a plurality of heat transfer tubes through which a cooling medium that exchanges heat with the steam exhausted from the steam turbine flows, and a recovery that covers the plurality of heat transfer tubes. and a condenser having a water vessel casing for converting said steam back to water. In this start-up method, a high-temperature fluid supply step of flowing into the condenser casing a high-temperature fluid having a temperature higher than the saturation temperature of the environment in the condenser casing; a suction step of sucking the inside of the water container casing; a steam turbine starting step of supplying steam from the boiler to the steam turbine after the suction step; and a hot fluid supplying step, the suction step and the steam turbine starting step a water-heat transfer tube contact step of bringing the water accumulated in the condenser casing into contact with at least some of the plurality of heat transfer tubes through which the cooling medium flows.

In this aspect, the water-heat transfer tube contacting step is performed before the hot fluid supplying step, the suction step and the steam turbine starting step. When the water-heat transfer tube contact step is performed, at least some of the plurality of heat transfer tubes through which the cooling medium flows are in contact with the condensate, which is the water accumulated in the condenser casing. The heat transfer coefficient between the liquid-phase medium to be cooled and the heat transfer tubes is much higher than the heat transfer rate between the gas-phase medium to be cooled and the heat transfer tubes. Therefore, in at least some of the heat transfer tubes, the heat exchange efficiency between the condensate containing the high-temperature fluid and the cooling medium in the heat transfer tubes is increased.

Therefore, in this aspect, even if the high-temperature fluid is caused to flow into the condenser casing, the high-temperature fluid can be effectively cooled. Therefore, in this aspect, even if the high-temperature fluid is allowed to flow into the condenser casing, it is possible to suppress the temperature rise in the condenser casing and the temperature rise of the condensate containing the high-temperature fluid. Furthermore, in this aspect, the pressure rise in the condenser casing can be suppressed.

Here, in the method for starting a steam turbine plant according to the aspect, in the water-heat transfer tube contacting step, the water level of water accumulated in the condenser casing is set to The water level in the condenser casing may be brought into contact with the at least part of the heat transfer tubes by raising the water level higher than the water level in the condenser casing.

Further, in the steam turbine plant start-up method of any of the above aspects, in the water-heat transfer tube contacting step, the water accumulated in the condenser casing is brought into contact with all of the plurality of heat transfer tubes. good too.

In any of the above aspects of the steam turbine plant start-up method, when the pressure in the condenser casing drops below a predetermined pressure in the execution of the suction step, the A water-heat transfer tube non-contact step may be performed in which the water in the heat transfer tubes and at least some of the plurality of heat transfer tubes through which the cooling medium flows are brought out of contact with each other.

In the steam turbine plant start-up method of the above aspect, in which the water-heat transfer tube non-contact process is executed, in the water-heat transfer tube non-contact process, the water level of the water accumulated in the condenser casing is It may be lower than the water level in the contacting step.

Further, in the steam turbine plant start-up method of the aspect, in the water-heat transfer tube contact step, the medium supply state of the cooling medium is changed to the one in contact with the water accumulated in the condenser casing. A first state may be set in which the cooling medium is sent into the heat transfer tubes of the part. In this case, when the pressure in the condenser casing drops below a predetermined pressure in the execution of the suction step, the medium supply state of the cooling medium is changed to the one of the plurality of heat transfer tubes. By setting the second state in which the cooling medium is not sent into the other heat transfer tubes and the cooling medium is sent into the other heat transfer tubes, the water accumulated in the condenser casing and the cooling medium flow A water-heat transfer tube non-contact step may be performed to bring the other heat transfer tubes out of contact with each other.

In any one of the above aspects of the method for starting a steam turbine plant, the steam turbine includes a steam turbine rotor that rotates about an axis, a steam turbine casing that covers the steam turbine rotor, and the steam turbine using steam. and a shaft seal device for sealing a gap between an end of the rotor and the steam turbine casing. In this case, a shaft sealing step of supplying steam to the shaft sealing device may be performed before performing the suction step.

In any one of the above aspects of the steam turbine plant start-up method, a water spraying step of spraying water from a position above the plurality of heat transfer tubes within the condenser casing during the high-temperature fluid supply step. may be executed.

In the steam turbine plant start-up method according to any of the above aspects, the steam turbine plant further includes a compressor for compressing air, and combustion of fuel in the air compressed by the compressor to generate combustion gas. and a gas turbine having a combustor and a turbine driven by said combustion gases. In this case, the boiler is an exhaust heat recovery boiler that generates steam from the heat of the exhaust gas discharged from the gas turbine.

In the start-up method for a steam turbine plant having the gas turbine, part of the air compressed by the compressor is extracted, and the air and part of the water accumulated in the condenser casing are extracted. and a hot component for directing the air cooled by the air cooling step to a hot component in the gas turbine in contact with the combustion gases. and a cooling step. In this case, in the high-temperature fluid supply step, the water heated in the air cooling step is caused to flow into the condenser casing as the high-temperature fluid.

In any one of the above aspects of the method for starting a steam turbine plant comprising the gas turbine, after the water-heat transfer tube contact step and before the suction step, the gas is supplied to the combustor as the fuel. A turbine start-up process may be performed.

In one aspect of the present invention, even if the hot fluid in gas or liquid phase needs to be cooled before being sucked into the condenser casing, the hot fluid can be cooled in the condenser. Therefore, according to one aspect of the present invention, a discharge device such as a flush pipe or a silencer for discharging the high-temperature fluid to the outside of the system becomes unnecessary, and equipment costs can be suppressed.

1 is a system diagram of a steam turbine plant in a first embodiment according to the present invention; FIG. It is a flowchart which shows the starting procedure of the steam turbine plant in 1st embodiment which concerns on this invention. It is a system diagram of a steam turbine plant in a second embodiment according to the present invention.

Various embodiments of the steam turbine plant according to the present invention will be described below with reference to the drawings.

"First Embodiment"
A first embodiment of a steam turbine plant according to the present invention will be described with reference to FIGS. 1 and 2. FIG.

As shown in FIG. 1, the steam turbine plant of this embodiment includes a gas turbine 10, an exhaust heat recovery boiler 20 that generates steam from the heat of the exhaust gas EG from the gas turbine 10, and a steam turbine 30 driven by steam; a condenser 40 that converts the steam from the steam turbine 30 back to water; Prepare. Therefore, the steam turbine plant of this embodiment is a combined cycle plant.

The gas turbine 10 includes a compressor 11 that compresses air A, a combustor 15 that burns fuel F in the air compressed by the compressor 11 to generate combustion gas, and a turbine driven by high-temperature and high-pressure combustion gas. 16 and an intermediate casing 14 . The compressor 11 has a compressor rotor 12 that rotates about the axis Ar, and a compressor casing 13 that covers the compressor rotor 12 . The turbine 16 has a turbine rotor 17 that rotates about an axis Ar, a turbine casing 18 that covers the turbine rotor 17, and a plurality of stationary blade rows 18b. The turbine rotor 17 has a rotor shaft 17a that rotates around the axis Ar, and a plurality of rotor blade rows 17b attached to the rotor shaft 17a. The multiple rotor blade rows 17b are arranged in the axial direction along which the axis Ar extends. Each rotor blade row 17b has a plurality of rotor blades arranged in a circumferential direction with respect to the axis Ar. A plurality of stator blade rows 18 b are fixed to the turbine casing 18 . Each of the plurality of stator blade rows 18b is arranged on the axial upstream side of any one of the plurality of rotor blade rows 17b. Note that the upstream side of the axis here is the side on which the compressor 11 is arranged with respect to the turbine 16, of the two sides in the axial direction. The compressor rotor 12 and the turbine rotor 17 rotate about the same axis Ar and are connected to each other to form a gas turbine rotor 19 . The intermediate casing 14 is arranged between the compressor casing 13 and the turbine casing 18 and connects both casings 13 and 18 . A combustor 15 is provided in this intermediate casing 14 . A fuel supply line 50 that supplies fuel F to the combustor 15 is connected to the combustor 15 . The fuel supply line 50 is provided with a fuel valve 51 for adjusting the flow rate of fuel supplied to the combustor 15 .

The steam turbine 30 has a steam turbine rotor 31 that rotates about an axis Ar, a steam turbine casing 32 that covers the steam turbine rotor 31, and a shaft seal device 33. The shaft seal device 33 is a device that seals a gap between the end of the steam turbine rotor 31 and the steam turbine casing 32 with steam from the outside. Note that the steam turbine 30 shown in FIG. 1 is a two-branch exhaust type steam turbine that splits incoming steam into two directions. However, the steam turbine of the present embodiment may be a steam turbine that does not split the inflowing steam.

The condenser 40 has a plurality of heat transfer tubes 42 through which a cooling medium such as water flows, and a condenser casing 41 covering the plurality of heat transfer tubes 42 . Steam from the steam turbine 30 flows into the condenser casing 41 and is cooled by heat exchange with the cooling medium in the plurality of heat transfer tubes 42 to become water. The condenser casing 41 is provided with an exhaust line 60 for discharging the gas inside the condenser casing 41 to the outside to reduce the pressure inside the condenser casing 41 . The exhaust line 60 is provided with a vacuum pump 61 for sucking the gas inside the condenser casing 41 . The condenser casing 41 is further provided with a water meter 43 for detecting the amount of condensed water accumulated in the condenser casing 41 and a pressure gauge 44 for detecting the pressure inside the condenser casing 41. , is provided.

A rotor of a generator 49 is mechanically connected to the steam turbine rotor 31 and the gas turbine rotor 19 . The generator 49 generates power from the rotation of the steam turbine rotor 31 and the gas turbine rotor 19 . Here, the rotor of one generator 49 is connected to the steam turbine rotor 31 and the rotor of the generator 49, but the rotor of the first generator is mechanically connected to the steam turbine rotor 31, A rotor of a second generator may be mechanically connected to the turbine rotor 19 . Also, the steam turbine rotor 31 and the gas turbine rotor 19 may be connected to other rotating machines other than the generator 49 .

In addition to the above, the steam turbine plant of the present embodiment includes a feedwater line 70, a main steam line 72, a main steam valve 73, a bypass line 74, a bypass valve 75, a seal steam line 76, a seal steam valve 77 , flow meter 78, air cooler 52, boost compressor 53, bleed air line 54, cooling air line 55, cooling water line 56, cooling water control valve (high temperature fluid control valve) 57, high temperature A fluid line 58 , a make-up water tank 66 , a make-up water line 67 , a make-up water control valve 68 , a drain facility 80 , a drain line 81 , a drain valve 82 , and a control device 100 .

The water supply line 70 connects the condenser casing 41 and the heat recovery boiler 20 and guides the condensate in the condenser casing 41 to the heat recovery boiler 20 . The aforementioned water supply pump 71b is provided in this water supply line 70 . Further, in the water supply line 70, a condensate pump 71a is provided at a position closer to the condenser 40 than the water supply pump 71b. The main steam line 72 connects the steam outlet of the heat recovery boiler 20 and the steam inlet of the steam turbine casing 32 and guides the steam generated by the heat recovery boiler 20 into the steam turbine casing 32 . A main steam valve 73 is provided in the main steam line 72 and adjusts the flow rate of steam flowing into the steam turbine casing 32 . The bypass line 74 is a line branched from a position closer to the heat recovery boiler 20 than the main steam valve 73 in the main steam line 72 . This bypass line 74 is connected to the condenser casing 41 . A bypass valve 75 is provided in this bypass line 74 and adjusts the flow rate of steam flowing through this bypass line 74 .

A portion of the steam generated by the heat recovery boiler 20 flows into the seal steam line 76 . The seal steam line 76 may be directly connected to the main steam line 72 or may be indirectly connected to the main steam line 72, for example, through other equipment. If the seal steam line 76 is directly connected to the main steam line 72, an attemperator is provided in the seal steam line 76 to reduce the temperature of the steam flowing through the seal steam line 76. This seal steam line 76 is connected to the shaft seal device 33 of the steam turbine 30 . A gap between the end of the steam turbine rotor 31 and the steam turbine casing 32 is sealed with steam supplied to the shaft seal device 33 . A flow meter 78 is provided in this seal steam line 76 to detect the flow rate of steam flowing through this seal steam line 76 . A seal steam valve 77 is provided in this seal steam line 76 . The seal steam valve 77 adjusts the flow rate of steam flowing through the seal steam line 76 so that the flow rate detected by the flow meter 78 becomes a predetermined flow rate. The flow meter 78 is an instrument for measuring the flow rate of steam supplied to the shaft seal device 33 . Therefore, if it is possible to measure the flow rate of steam supplied to the shaft seal device 33, this instrument does not directly measure the flow rate of steam, but indirectly measures the flow rate of steam such as a pressure gauge. It may be something to do.

A bleed line 54 connects the intermediate casing 14 of the gas turbine 10 and the air inlet of the air cooler 52 . This bleed line 54 bleeds the air that has been compressed by the compressor 11 and has reached the intermediate casing 14 from the intermediate casing 14 and guides it to the air cooler 52 . Cooling air line 55 connects the air outlet of air cooler 52 and the hot components of gas turbine 10 and directs air from air cooler 52 to the hot components. Hot components are those components in the gas turbine 10 that are in contact with the hot combustion gases. For example, they are stator blades and rotor blades of the turbine 16, parts of the combustor 15, and the like. A cooling air line 55 is provided with a boost compressor 53 that boosts the air from the air cooler 52 and delivers it to the hot components. The cooling water line 56 is a line branched from a position closer to the exhaust heat recovery boiler 20 than the water supply pump 71b in the water supply line 70 . This cooling water line 56 is connected to the water inlet of the air cooler 52 . The cooling water line 56 is provided with a cooling water control valve (high-temperature fluid control valve) 57 for adjusting the flow rate of water flowing through the cooling water line 56 . A hot fluid line 58 connects the water outlet of the air cooler 52 and the condenser casing 41 and directs the water from the air cooler 52 into the condenser casing 41 . The air cooler 52 heat-exchanges the air compressed by the compressor 11 with water, cooling the air and heating the water. The air cooled by the air cooler 52 is pressurized by the boost compressor 53 and sent to the high temperature parts to cool the high temperature parts. The water heated by the air cooler 52 flows into the condenser casing 41 via the hot fluid line 58 as hot fluid.

The make-up water tank 66 stores pure water as make-up water. The make-up water line 67 connects the make-up water tank 66 and the condenser casing 41 and guides make-up water into the make-up water tank 66 into the condenser casing 41 . A make-up water control valve 68 is provided in this make-up water line 67 and regulates the flow rate of make-up water flowing into the condenser casing 41 .

The drainage facility 80 is a facility for receiving and treating condensate accumulated in the condenser casing 41 . The drain line 81 branches from a position between the condensate pump 71 a and the water supply pump 71 b in the water supply line 70 and is connected to the drainage facility 80 . A drain valve 82 is provided in the drain line 81 to adjust the flow rate of water flowing through the drain line 81 .

The control device 100 controls operations of the condensate pump 71a, the water supply pump 71b, the vacuum pump 61, and the valves described above.

Next, according to the flowchart shown in FIG. 2, a procedure for restarting the steam turbine plant after stopping the steam turbine plant will be described.

After stopping the steam turbine plant, condensate is accumulated in the condenser casing 41 before starting the steam turbine plant again. All the heat transfer tubes 42 inside the condenser casing 41 are not submerged in the condensate. Also, before starting the steam turbine plant, the fuel valve 51, the main steam valve 73, the cooling water control valve 57, the seal steam valve 77, the make-up water control valve 68, and the drain valve 82 are closed. On the other hand, before starting up the steam turbine plant, the bypass valve 75 is open. Also, before starting the steam turbine plant, the condensate pump 71a, the feedwater pump 71b and the vacuum pump 61 are stopped. Since the vacuum pump 61 is stopped before starting the steam turbine plant, the pressure in the condenser casing 41 is approximately atmospheric pressure.

In the start-up process of the steam turbine plant, the control device 100 first sends an open instruction to the make-up water control valve 68 so that the amount of condensate in the condenser casing 41 reaches a predetermined start-up water amount Ls. . The start-up water amount Ls is the amount of water in which a part of the heat transfer tubes 42p located on the lower side of the plurality of heat transfer tubes 42 can be submerged in the condensed water. Upon receipt of this instruction, the make-up water control valve 68 allows make-up water in the make-up water tank 66 to flow into the condenser casing 41 so that the amount of water detected by the water meter 43 becomes the amount of water at startup Ls. As a result, of the heat transfer tubes 42, some of the lower heat transfer tubes 42p come into contact with the condensate (S1: water-heat transfer tube contact step).

Next, the controller 100 drives the condensate pump 71a and the feedwater pump 71b to supply the condensate in the condenser casing 41 as feedwater to the exhaust heat recovery boiler 20 (S2: feedwater step). Subsequently, the control device 100 sends an opening instruction to the cooling water control valve (high-temperature fluid control valve) 57 . As a result, the cooling water control valve 57 is opened, and part of the condensate in the condenser casing 41 is supplied as cooling water to the air cooler 52 via the cooling water line 56 . This cooling water returns to the condenser casing 41 via the high-temperature fluid line 58 (S3: water supply/water recovery step).

When water is accumulated in the evaporation drum of the heat recovery boiler 20 by driving the condensate pump 71a and the feedwater pump 71b, the control device 100 sends a drive instruction to an activation device (not shown) and An open instruction is sent to the valve 51 (S4: gas turbine startup step). As a result, the starting device starts rotating the gas turbine rotor 19 and supplying the fuel F to the combustor 15 . As the gas turbine rotor 19 rotates, air is compressed in the compressor 11 . This air is sent from the compressor 11 to the combustor 15 . In the combustor 15, the fuel F is combusted in this air to generate combustion gas. This combustion gas flows into the turbine casing 18 and imparts rotational force to the turbine rotor 17 . The combustion gases also heat hot components of the gas turbine 10 . When the rotation speed of the gas turbine rotor 19 reaches or exceeds a predetermined rotation speed, the control device 100 sends a stop instruction to the starting device. Further, the control device 100 sends a valve opening instruction to the fuel valve 51 so that the flow rate of the fuel supplied to the combustor 15 increases until the generator output reaches, for example, the rated output.

A portion of the air compressed by compressor 11 is sent to air cooler 52 via bleed line 54 . In the air cooler 52, heat is exchanged between the air and the cooling water, and the air is cooled, while the cooling water is heated to become a high-temperature fluid (S5: air cooling step). The air cooled by the air cooler 52 is sent to the high temperature components of the gas turbine 10 via the cooling air line 55 to cool the high temperature components (S6: high temperature component cooling step). The water heated by the air cooler 52 flows through the high temperature fluid line 58 into the condenser casing 41 as high temperature fluid (S7: high temperature fluid supply step).

Note that the high-temperature fluid supply step (S7) does not include the control device 100 sending an opening instruction to the cooling water control valve (high-temperature fluid control valve) 57, and the water supply/water recovery step ( In S3), the control device 100 sends an opening instruction to the cooling water control valve (high-temperature fluid control valve) 57 . However, this high-temperature fluid supply step (S7) is a high-temperature fluid supply step in a narrow sense. 57 to send an open indication.

The temperature of the hot fluid from air cooler 52 is, for example, 150°C. At this time, the pressure inside the condenser casing 41 is substantially the atmospheric pressure as described above. Therefore, water in the liquid phase, which is higher than the saturation temperature (approximately 100° C.) under the environment (approximately atmospheric pressure) in the condenser casing 41 , flows into the condenser casing 41 . When the liquid-phase high-temperature fluid flows into the condenser casing 41, part of it flashes to become vapor (gas-phase water) at approximately 100°C, and part of it becomes liquid-phase water at 100°C. . Both of these gas phase water and liquid phase water are cooled by exchanging heat with the cooling medium flowing through the plurality of heat transfer tubes 42 in the condenser casing 41 . The vapor-phase water becomes liquid-phase water as a result of heat exchange with the cooling medium.

Here, when the inside of the condenser casing 41 is not sucked and all the heat transfer tubes 42 in the condenser casing 41 are not in contact with the condensate, the high-temperature fluid in the condenser casing 41 is will be described. When the steam turbine 30 is in rated operation, the amount of condensed water in the condenser casing 41 corresponding to the rated operation is defined as the water amount Lr during rated operation. This water amount Lr during rated operation is a water amount at which all the heat transfer tubes 42 in the condenser casing 41 do not come into contact with condensate, like the water amount in the above-described state.

The heat transfer coefficient between the gas-phase high-temperature fluid and the heat transfer tubes 42 is lower than the heat transfer coefficient between the liquid-phase high-temperature fluid and the heat transfer tubes 42 . Moreover, the liquid-phase high-temperature fluid does not contact the entire surfaces of the plurality of heat transfer tubes 42 , but only part of the surfaces of the plurality of heat transfer tubes 42 . Moreover, when the inside of the condenser casing 41 is not sucked, the heat transfer coefficient between the high-temperature fluid in the gas phase or the liquid phase and the heat transfer tube 42 is low. For this reason, the heat exchange efficiency between the gas-phase or liquid-phase high-temperature fluid and the cooling medium in the heat transfer tubes 42 is low, and the gas-phase or liquid-phase high-temperature fluid cannot be efficiently cooled. As a result, the temperature inside the condenser casing 41 rises, and the temperature of the condensate containing the liquid-phase high-temperature fluid also rises.

When the temperature of the condensate containing the liquid-phase high-temperature fluid also rises, the temperature of the cooling water supplied to the air cooler 52 also rises. Therefore, the cooling efficiency of the air in the air cooler 52 is lowered. Furthermore, the temperature of the high-temperature fluid, which is water heated by heat exchange with the air in the air cooler 52, also rises. This results in a vicious cycle in which the temperature inside the condenser casing 41 and the temperature of the condensate containing the liquid-phase high-temperature fluid further increase. Moreover, when the temperature inside the condenser casing 41 rises, the time required to increase the degree of vacuum inside the condenser casing 41 becomes longer. In addition, since the vapor-phase water cannot be efficiently turned into liquid-phase water within the condenser casing 41, the pressure within the condenser casing 41 increases, and the condenser casing 41 or the steam turbine casing 32 is protected. rupture disc may be damaged.

Therefore, when the inside of the condenser casing 41 is not sucked and all the heat transfer tubes 42 in the condenser casing 41 are not in contact with the condensate, the high-temperature fluid is introduced into the condenser casing 41. I don't like to let it flow. Therefore, in this state, the high-temperature fluid must not flow into the condenser casing 41 and must be discharged to the outside.

Also in this embodiment, the heat exchange rate between the cooling medium in the heat transfer tubes 42 that are not submerged in the condensate and the high-temperature fluid in the gas phase or liquid phase is the same as in the above-described case. to low. Therefore, when the high-temperature fluid flows into the condenser casing 41, the high-temperature fluid acts to raise the temperature of the condensate. In the present embodiment, as described above, some of the heat transfer tubes 42p are submerged in the condensed water, and the entire surfaces of these some of the heat transfer tubes 42p are in contact with liquid phase water. Therefore, the heat transfer coefficient between this water and some of the heat transfer tubes 42p is higher than the heat transfer coefficient between the high temperature fluid and the heat transfer tubes 42 that are not submerged in the condensate. Moreover, since this heat transfer coefficient is the heat transfer coefficient in the condensed water, it is substantially constant regardless of whether or not the condenser casing 41 is sucked into the condenser casing 41 . Therefore, the heat exchange rate between the condensate containing the liquid-phase high-temperature fluid and some of the heat transfer tubes 42p is high. As a result, in this embodiment, even if the high-temperature fluid in the gas phase or the liquid phase flows into the condenser casing 41, the high-temperature fluid can be effectively cooled. Therefore, in the present embodiment, even if the gas-phase or liquid-phase high-temperature fluid is allowed to flow into the condenser casing 41, the temperature inside the condenser casing 41 rises and the condensed water containing the liquid-phase high-temperature fluid increases. Temperature rise can be suppressed. Furthermore, in this embodiment, the pressure rise in the condenser casing 41 can be suppressed.

When the gas turbine 10 is started, high-temperature exhaust gas from the gas turbine 10 flows through the heat recovery boiler 20 . In the exhaust heat recovery boiler 20, the water from the condenser 40 and the exhaust gas are heat-exchanged to heat the water into steam. When steam starts to be generated in the heat recovery boiler 20, the liquid existing in the water circulation system comprising the condenser 40, the feed water line 70, the heat recovery boiler 20, the main steam line 72, and the steam turbine 30 The amount of phase water is reduced. Therefore, immediately after the gas turbine 10 is started, the make-up water control valve 68 is open in order to maintain the amount of condensate in the condenser casing 41, and the make-up water from the make-up water tank 66 is supplied to the condenser. It flows into the casing 41 . Before starting the gas turbine 10, the make-up water control valve 68 is opened to increase the water level in the condenser casing 41, and when the gas turbine 10 starts, the make-up water control valve 68 is closed. good too.

When steam starts to be generated from the heat recovery boiler 20 , the control device 100 sends an open instruction to the seal steam valve 77 . Note that the control device 100 recognizes that the exhaust heat recovery boiler 20 has started to generate steam from the pressure in the main steam line 72 or the like. When the seal steam valve 77 receives this open instruction, the seal steam valve 77 opens and steam is supplied to the shaft seal device 33 of the steam turbine 30 via the seal steam line 76 . When the flow rate of steam detected by a flow meter 78 provided in the seal steam line 76 reaches a predetermined flow rate, the gap between the end of the steam turbine rotor 31 and the steam turbine casing 32 is sealed with steam. (S8: shaft sealing step).

When the steam flow rate detected by the flow meter 78 reaches a predetermined flow rate, the control device 100 sends a drive instruction to the vacuum pump 61 . Upon receiving this instruction, the vacuum pump 61 starts to drive and sucks the inside of the condenser casing 41 (S9: suction step).

When the degree of vacuum detected by the pressure gauge 44 provided in the condenser casing 41 reaches or exceeds a predetermined degree of vacuum, the control device 100 sends an open instruction to the drain valve 82 . Also, the control device 100 sends a close instruction to the make-up water control valve 68 before sending an open instruction to the drain valve 82 . As a result, condensate flows into the condenser casing 41 through the drainage line 81 into the drainage facility 80, and the amount of water in the condenser casing 41 decreases. When the amount of water in the condenser casing 41 detected by the water meter 43 reaches the predetermined rated operating water amount Lr, the control device 100 sends a close instruction to the drain valve 82 . Note that, as described above, the water amount Lr during rated operation is the amount of water that prevents all the heat transfer tubes 42 in the condenser casing 41 from coming into contact with the condensate, in other words, the amount of water that prevents all the heat transfer tubes 42 from being submerged in the condensate. is. As a result, of the plurality of heat transfer tubes 42, some of the heat transfer tubes 42p submerged in the condensate are no longer in contact with the condensate (S10: water-heat transfer tube non-contact step).

After the water-heat transfer tube non-contact step (S10) is executed, when the conditions for steam from the heat recovery boiler 20 to be supplied to the steam turbine 30 are met, the control device 100 sends an open instruction to the main steam valve 73 and simultaneously sends an open instruction to the main steam valve 73. , sends a close command to the bypass valve 75 . As a result, the steam from the heat recovery boiler 20 begins to be supplied to the steam turbine 30, and the steam turbine 30 starts to operate (S11: steam turbine starting step). Execution of the steam turbine start-up step (S11) completes the start-up step of the steam turbine plant.

The steam exhausted from the steam turbine 30 flows into the condenser casing 41, exchanges heat with the cooling medium flowing through the plurality of heat transfer tubes 42, and is cooled to become condensed water. This condensed water is sent as feed water to the heat recovery boiler 20 via the feed water line 70 and becomes steam.

When the inside of the condenser casing 41 is sucked, the heat transfer coefficient between the medium to be cooled such as steam and the heat transfer tubes 42 is higher than when the inside of the condenser casing 41 is not sucked. Therefore, in this state, the heat exchange rate between the medium to be cooled and the cooling medium in the heat transfer tubes 42 is high. Further, if a portion of the heat transfer tubes 42p are submerged in the condensate in the condenser casing 41, as described above, heat exchange between the condensate and the cooling medium in the portion of the heat transfer tubes 42p higher rate. Therefore, in a state where the inside of the condenser casing 41 is sucked, the medium to be cooled is excessively cooled, and the temperature of the condensate, which is the product of cooling of the medium to be cooled, drops. When the temperature of the condensate drops, the temperature of the feed water supplied to the heat recovery boiler 20 also drops, so the thermal energy for converting this feed water into steam increases. That is, when the temperature of the condensate drops, the efficiency of steam generation in the heat recovery boiler 20 drops. Therefore, in this embodiment, after the inside of the condenser casing 41 starts to be sucked, the amount of water inside the condenser casing 41 is reduced so that all the heat transfer tubes 42 are not in contact with the condensate.

As described above, in the present embodiment, even if it is necessary to cool the gas-phase or liquid-phase high-temperature fluid before sucking it into the condenser casing 41, the high-temperature fluid is cooled by the condenser 40. can do. Therefore, in this embodiment, a discharge device such as a flush pipe or a silencer for discharging the high-temperature fluid to the outside of the system becomes unnecessary, and the facility cost can be suppressed.

In the water-heat transfer tube contact step (S1) described above, only the lower heat transfer tubes 42p of the plurality of heat transfer tubes 42 are brought into contact with condensate. However, when the temperature of the high-temperature fluid is high or when the flow rate of the high-temperature fluid is large, heat exchange between the high-temperature fluid and the cooling medium in the heat transfer tubes 42 is performed by bringing all the heat transfer tubes 42 into contact with the condensate. rate can be increased.

Further, as shown in FIG. 2, during the high-temperature fluid supply step (S7), a water spraying step (S12) of spraying water from a position above the plurality of heat transfer tubes 42 within the condenser casing 41 is executed. You may When water is sprayed from a position above the plurality of heat transfer tubes 42, the high-temperature fluid exchanges heat with the cooling medium inside the heat transfer tubes 42 and also with the sprayed water. Therefore, the high-temperature fluid can be cooled more effectively by executing the water spray step (S12). In executing this water spray step (S12), as shown in FIG. Furthermore, a spray water line 62 and a spray water control valve 63 are added to the steam turbine plant of the embodiment described above. The spray water line 62 is a line branching from a position between the condensate pump 71a and the water supply pump 71b in the water supply line 70. As shown in FIG. This spray water line 62 is connected to the water sprayer 45 . A spray water control valve 63 is provided in the spray water line 62 to adjust the flow rate of water flowing through the spray water line 62 . In this case, the control device 100 sends an open instruction to the spray water control valve 63 at substantially the same timing as the start of the high-temperature fluid supply step (S7). The control device 100 starts executing the suction step ( S9 ), and when the heat transfer coefficient between the medium to be cooled and the heat transfer tube 42 increases, sends a close instruction to the spray water control valve 63 .

"Second embodiment"
A second embodiment of a steam turbine plant according to the present invention will be described with reference to FIG.

The start-up procedure of the steam turbine plant of this embodiment is the same as the start-up procedure of the first embodiment. However, during this startup procedure, the configuration for executing the water-heat transfer tube contact step (S1) and the water-heat transfer tube non-contact step (S10) differs from that of the first embodiment.

Like the condenser 40 of the first embodiment, the condenser 40 of the present embodiment also includes a plurality of heat transfer tubes 42 through which a cooling medium such as water flows, and a condenser casing 41 covering the plurality of heat transfer tubes 42. , have In the present embodiment, a group of some heat transfer tubes 42 among the plurality of heat transfer tubes 42 is defined as a first heat transfer tube group 42a, and a group of the remaining heat transfer tubes 42 is defined as a second heat transfer tube group 42b. All the heat transfer tubes 42 forming the first heat transfer tube group 42 a are located above all the heat transfer tubes 42 forming the second heat transfer tube group 42 b among the plurality of heat transfer tubes 42 . All the heat transfer tubes 42 constituting the first heat transfer tube group 42a are not submerged in the condensed water of the rated operating water amount Lr described above. Further, all the heat transfer tubes 42 constituting the second heat transfer tube group 42b are submerged in the condensed water of the rated operating water amount Lr described above.

The steam turbine plant of this embodiment includes a cooling medium line 64 that guides a cooling medium such as water to the plurality of heat transfer tubes 42 and a switch 65 . The cooling medium line 64 includes a cooling medium main line 64m, a first cooling medium line 64a branching from the cooling medium main line 64m, and a second cooling medium line 64b branching from the cooling medium main line 64m. and have The first cooling medium line 64a is connected to the plurality of heat transfer tubes 42 forming the first heat transfer tube group 42a. The second cooling medium line 64b is connected to the plurality of heat transfer tubes 42 forming the second heat transfer tube group 42b. The switching device 65 has a first cooling medium valve 65a and a second cooling medium valve 65b. The first cooling medium valve 65a is provided in the first cooling medium line 64a and adjusts the flow rate of the cooling medium flowing through the first cooling medium line 64a. The second cooling medium valve 65b is provided in the second cooling medium line 64b and adjusts the flow rate of the cooling medium flowing through the second cooling medium line 64b.

In this embodiment, in the water-heat transfer tube contact step (S1), the control device 100 sends an open instruction to the first cooling medium valve 65a and the second cooling medium valve 65b. As a result, the first cooling medium valve 65a and the second cooling medium valve 65b are opened, and the cooling medium is supplied to both the first heat transfer tube group 42a that is not in contact with the condensate and the second heat transfer tube group 42b that is in contact with the condensate. is supplied. That is, the medium supply state to the plurality of heat transfer tubes 42 becomes the second state. This second state is a state obtained by executing the water-heat transfer tube contact step (S1) in the first embodiment, that is, some of the heat transfer tubes 42 are submerged in condensed water. It is basically the same as the current state.

Therefore, in the present embodiment, even if the high-temperature fluid flows into the condenser casing 41 in the high-temperature fluid supply step (S7), the water-heat transfer tube contact step (S1) is performed. Fluids can be effectively cooled.

During this water-heat transfer tube contact step (S1), when the amount of condensed water in the condenser casing 41 decreases due to an increase in the amount of steam generated from the heat recovery boiler 20, Similarly, make-up water may be supplied from the make-up water tank 66 into the condenser casing 41 .

In the present embodiment, in the water-heat transfer tube non-contact step (S10), the control device 100 continues to send an open instruction to the first cooling medium valve 65a and send a close instruction to the second cooling medium valve 65b. . As a result, the first cooling medium valve 65a is kept open, the second cooling medium valve 65b is closed, and the cooling medium is supplied only to the first heat transfer tube group 42a that is not in contact with the condensate. That is, the medium supply state to the plurality of heat transfer tubes 42 becomes the first state. This first state is the state obtained by executing the water-heat transfer tube non-contact step (S10) in the first embodiment, that is, the state in which all the heat transfer tubes 42 through which the cooling medium flows are not submerged in the condensed water. is basically in the same state.

Therefore, also in this embodiment, it is possible to suppress the temperature drop of the condensate by executing the water-heat transfer tube contact step (S10).

In the present embodiment, from after the gas turbine start-up step (S4) to the suction step (S8), due to an increase in the amount of steam generated from the heat recovery boiler 20, the condensate in the condenser casing 41 When the amount of water decreases, it is preferable to supply makeup water from the makeup water tank 66 into the condenser casing 41 .

Also, in this embodiment, as illustrated in the first embodiment, the water sprayer 45 is provided in the condenser casing 41, the spray water line 62 and the spray water control valve 63 are added, and the high-temperature fluid supply process ( The water spraying step (S12) may be performed in parallel with the execution of S7).

"Variation"
Each of the above embodiments is an example in which the liquid-phase water heated by the air cooler 52 is made to flow into the condenser casing 41 as a high-temperature fluid. However, if it becomes necessary to cool gas-phase or liquid-phase high-temperature fluid other than the high-temperature fluid from the air cooler 52 before sucking the inside of the condenser casing 41, this high-temperature fluid is 41.

Each of the steam turbine plants of the above embodiments is an example in which the gas turbine 10 is provided, and the boiler is the exhaust heat recovery boiler 20 that utilizes the heat of the exhaust gas from the gas turbine 10 to generate steam. However, the steam turbine plant may not include the gas turbine 10 and the boiler may be a conventional boiler having a furnace. Also, the steam turbine plant of each embodiment may include a high-pressure steam turbine, an intermediate-pressure steam turbine, a low-pressure steam turbine, and the like.

10: Gas Turbine 11: Compressor 12: Compressor Rotor 13: Compressor Casing 14: Intermediate Casing 15: Combustor 16: Turbine 17: Turbine Rotor 17a: Rotor Shaft 17b: Rotor Blade Row 18: Turbine Casing 18b: Stator Blade Row 19: Gas turbine rotor 20: Heat recovery boiler (or boiler)
30: Steam turbine 31: Steam turbine rotor 32: Steam turbine casing 33: Shaft seal device 40: Condenser 41: Condenser casing 42: Heat transfer tube 42p: Partial heat transfer tube 42a: First heat transfer tube group 42b: Second heat transfer tube group 43: Water gauge 44: Pressure gauge 45: Water sprayer 49: Generator 50: Fuel supply line 51: Fuel valve 52: Air cooler 53: Boost compressor 54: Bleed air line 55: Cooling air line 56 : Cooling water line 57: Cooling water control valve (high-temperature fluid control valve)
58: Hot fluid line 60: Exhaust line 61: Vacuum pump 62: Spray water line 63: Spray water control valve 64: Cooling medium line 64m: Cooling medium main line 64a: First cooling medium line 64b: Second cooling medium line 65 : Switching device 65a: First cooling medium valve 65b: Second cooling medium valve 66: Make-up water tank 67: Make-up water line 68: Make-up water control valve 69: Make-up water pump 70: Water supply line 71a: Condensate pump 71b: Water supply Pump 72: Main steam line 73: Main steam valve 74: Bypass line 75: Bypass valve 76: Seal steam line 77: Seal steam valve 78: Flow meter 80: Drainage facility 81: Drain line 82: Drain valve 100: Controller A : Air EG: Exhaust gas F: Fuel Ar: Axis line Lr: Water volume at rated operation Ls: Water volume at startup

Claims (16)

a boiler that produces steam;
a steam turbine driven by steam from the boiler;
a main steam valve that regulates a flow rate of steam flowing from the boiler to the steam turbine;
a condenser having a plurality of heat transfer tubes through which a cooling medium that exchanges heat with the steam exhausted from the steam turbine flows, and a condenser casing covering the plurality of heat transfer tubes, the condenser returning the steam to water;
a supply water tank in which supply water is stored;
a make-up water control valve that adjusts the flow rate of make-up water supplied from the make-up water tank into the condenser casing;
a vacuum pump for sucking the inside of the condenser casing;
a high-temperature fluid line that guides into the condenser a high-temperature fluid having a temperature higher than the saturation temperature of the environment in the condenser casing;
a hot fluid control valve that adjusts the flow rate of the hot fluid flowing through the hot fluid line;
a controller;
with
The control device is
a hot fluid supply step of sending an open instruction to the hot fluid control valve to allow the hot fluid to flow from the hot fluid line into the condenser casing;
a suction step of sending a drive instruction to the vacuum pump to suck the inside of the condenser casing after the high-temperature fluid supply step;
a steam turbine start-up step of sending an open instruction to the main steam valve to supply steam from the boiler to the steam turbine after the suction step;
Before the high-temperature fluid supply step, the suction step, and the steam turbine start-up step, the amount of water accumulated in the condenser casing is controlled by adjusting the opening degree of the make-up water control valve. a water-heat transfer tube contacting step of bringing water accumulated in the condenser casing into contact with at least some of the plurality of heat transfer tubes through which the cooling medium flows;
run the
steam turbine plant. In the steam turbine plant of claim 1,
In the water-heat transfer tube contact step, the control device controls the water level of the water accumulated in the condenser casing to be lower than the water level of the water accumulated in the condenser casing during rated operation of the steam turbine. By increasing the height of the
steam turbine plant. In the steam turbine plant according to claim 1 or 2,
a drainage facility for receiving water accumulated in the condenser casing;
a drainage line for guiding water accumulated in the condenser casing to the drainage facility;
a drain valve for adjusting the flow rate of water flowing through the drain line;
with
The control device is
When the pressure in the condenser casing drops below a predetermined pressure in the execution of the suction step, the amount of water accumulated in the condenser casing is reduced by adjusting the opening of the drain valve. Water-heat-transfer-tube non-contact by controlling to make the water accumulated in the condenser casing out of contact with at least a part of the plurality of heat transfer tubes through which the cooling medium flows. carry out the process,
steam turbine plant. a boiler that produces steam;
a steam turbine driven by steam from the boiler;
a main steam valve that regulates a flow rate of steam flowing from the boiler to the steam turbine;
a condenser having a plurality of heat transfer tubes through which a cooling medium that exchanges heat with the steam exhausted from the steam turbine flows, and a condenser casing covering the plurality of heat transfer tubes, the condenser returning the steam to water;
Switching the medium supply state between a first state in which the cooling medium is sent to some of the plurality of heat transfer tubes and a second state in which the cooling medium is not sent to some of the heat transfer tubes. machine and
a vacuum pump for sucking the inside of the condenser casing;
a high-temperature fluid line that guides into the condenser a high-temperature fluid having a temperature higher than the saturation temperature of the environment in the condenser casing;
a hot fluid control valve that adjusts the flow rate of the hot fluid flowing through the hot fluid line;
a controller;
with
The control device is
a hot fluid supply step of sending an open instruction to the hot fluid control valve to allow the hot fluid to flow from the hot fluid line into the condenser casing;
a suction step of sending a drive instruction to the vacuum pump to suck the inside of the condenser casing after the high-temperature fluid supply step;
a steam turbine start-up step of sending an open instruction to the main steam valve to supply steam from the boiler to the steam turbine after the suction step;
Before the high-temperature fluid supply step, the suction step, and the steam turbine start-up step, an instruction is sent to the switching device to switch to the first state, and the water accumulated in the condenser casing and the water a water-heat transfer tube contacting step of contacting the part of the heat transfer tubes through which the cooling medium flows;
run the
steam turbine plant. In the steam turbine plant according to claim 4,
The second state is a state in which the cooling medium is not sent to the part of the plurality of heat transfer tubes and the cooling medium is sent to the other heat transfer tubes,
The other heat transfer tubes are positioned higher than the part of the heat transfer tubes among the plurality of heat transfer tubes, and remain in the condenser casing when the steam turbine is in rated operation. It is a heat transfer tube that does not submerge in water,
Some of the heat transfer tubes are heat transfer tubes that are submerged in water that has accumulated in the condenser casing when the steam turbine is in rated operation.
steam turbine plant. In the steam turbine plant according to claim 5,
The control device is
In the execution of the suction step, when the pressure in the condenser casing drops below a predetermined pressure, an instruction is sent to the switching device to switch to the second state, and the pressure in the condenser casing is performing a water-heat transfer tube non-contact step in which the water accumulated in the cooling medium is not in contact with the other heat transfer tube through which the cooling medium flows;
steam turbine plant. In the steam turbine plant according to any one of claims 1 to 6,
The steam turbine includes a steam turbine rotor that rotates about an axis, a steam turbine casing that covers the steam turbine rotor, and a shaft that uses steam to seal a gap between the end of the steam turbine rotor and the steam turbine casing. a sealing device;
a seal steam line that guides part of the steam generated from the boiler to the shaft seal device;
a seal steam valve that regulates the flow rate of steam flowing through the seal steam line;
with
The control device sends an open instruction to the seal steam valve to perform a shaft sealing step of supplying steam to the shaft sealing device before performing the suction step.
steam turbine plant. In the steam turbine plant according to any one of claims 1 to 7,
The condenser is
a water sprayer that sprays water from a position above the plurality of heat transfer tubes within the condenser casing;
The control device executes a water spraying step of spraying water from the water sprayer during the hot fluid supply step.
steam turbine plant. In the steam turbine plant according to any one of claims 1 to 8,
a gas turbine having a compressor for compressing air, a combustor for burning fuel in the air compressed by the compressor to generate combustion gases, and a turbine driven by the combustion gases;
a fuel valve for adjusting the flow rate of fuel supplied to the combustor;
an air extraction line for extracting a portion of the air compressed by the compressor;
a cooling water line through which part of the water accumulated in the condenser casing flows;
an air cooler for exchanging heat between air from the bleed line and water from the cooling water line to cool the air while heating the water;
a cooling air line directing the air cooled by the air cooler to hot components in the gas turbine in contact with the combustion gases;
with
The boiler is an exhaust heat recovery boiler that generates steam from the heat of the exhaust gas discharged from the gas turbine,
The high-temperature fluid line is a line that allows the water heated by the air cooler to flow into the condenser casing as the high-temperature fluid,
The high-temperature fluid control valve is a control valve that regulates the flow rate of water flowing through the cooling water line or water flowing through the high-temperature fluid line.
steam turbine plant. In the steam turbine plant of claim 9,
The control device is
After the water-heat transfer tube contact step and before the suction step, a gas turbine start-up step of sending an open instruction to the fuel valve to start supplying the fuel to the combustor is executed.
steam turbine plant. a boiler that produces steam;
a steam turbine driven by steam from the boiler;
a condenser having a plurality of heat transfer tubes through which a cooling medium that exchanges heat with the steam exhausted from the steam turbine flows, and a condenser casing covering the plurality of heat transfer tubes, the condenser returning the steam to water;
A method for starting a steam turbine plant comprising:
a high-temperature fluid supply step of flowing into the condenser casing a high-temperature fluid having a temperature higher than the saturation temperature of the environment in the condenser casing;
a suction step of sucking the inside of the condenser casing after the high-temperature fluid supply step;
a steam turbine start-up step of supplying steam from the boiler to the steam turbine after the suction step;
Prior to the high-temperature fluid supply step, the suction step, and the steam turbine start-up step, the water accumulated in the condenser casing is removed from at least a portion of the plurality of heat transfer tubes through which the cooling medium flows. A water-heat transfer tube contacting step in contact with the heat tube;
run the
A method for starting a steam turbine plant. A method for starting a steam turbine plant according to claim 11,
In the water-heat transfer tube contact step, the water level of the water accumulated in the condenser casing is made higher than the water level of the water accumulated in the condenser casing during rated operation of the steam turbine. Bringing the water accumulated in the condenser casing into contact with the at least part of the heat transfer tubes;
A method for starting a steam turbine plant. A method for starting a steam turbine plant according to claim 11 or 12,
When the pressure in the condenser casing drops below a predetermined pressure in the execution of the suction step, the water remaining in the condenser casing and the cooling medium among the plurality of heat transfer tubes performing a water-tube non-contact step that brings out of contact with at least a portion of the heat transfer tubes through which
A method for starting a steam turbine plant. A method for starting a steam turbine plant according to claim 13, comprising:
In the water-heat transfer tube non-contact step, the water level of the water accumulated in the condenser casing is made lower than the water level in the water-heat transfer tube contact step,
A method for starting a steam turbine plant. A method for starting a steam turbine plant according to claim 11,
In the water-heat transfer tube contact step, the medium supply state of the cooling medium is changed to the first state of sending the cooling medium into the part of the heat transfer tubes that are in contact with the water accumulated in the condenser casing. west,
In the execution of the suction step, when the pressure in the condenser casing decreases to a predetermined pressure or less, the medium supply state of the cooling medium is changed to the heat transfer state of the part of the plurality of heat transfer tubes. By setting the second state in which the cooling medium is not sent into the pipes and the cooling medium is sent to other heat transfer tubes, the water accumulated in the condenser casing and the water in which the cooling medium is flowing Execute a water-heat transfer tube non-contact process that makes contact with other heat transfer tubes,
A method for starting a steam turbine plant. In the method for starting a steam turbine plant according to any one of claims 11 to 15,
The steam turbine plant further comprises:
a gas turbine having a compressor for compressing air, a combustor for burning fuel in the air compressed by the compressor to generate combustion gases, and a turbine driven by the combustion gases;
The boiler is an exhaust heat recovery boiler that generates steam from the heat of the exhaust gas discharged from the gas turbine,
performing a gas turbine start-up step of supplying the fuel to the combustor before the suction step;
A method for starting a steam turbine plant.

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