Steam turbine cleaning method

Abstract

This invention provides a method for cleaning a steam turbine that allows the steam turbine to be cleaned without opening the casing of the steam turbine. [Solution] A method for cleaning a steam turbine, comprising a turbine rotor and a turbine casing having a chamber for rotatably housing the turbine rotor, comprises a cleaning fluid supply step of supplying cleaning fluid to the chamber to a predetermined height or higher so that a portion of the turbine rotor is submerged; a cleaning step of cleaning the inside of the chamber with the cleaning fluid; and a cleaning fluid discharge step of discharging the cleaning fluid used to clean the inside of the chamber to the outside of the chamber.

Description

Technical Field

[0001] The present disclosure relates to a method for cleaning a steam turbine.

Background Art

[0002] For a condenser for condensing steam discharged from a steam turbine, when seawater is used for cooling the steam, if damage such as holes occurs in the cooling pipes due to long-term operation, seawater may mix into the condensate line through which the condensate condensed in the condenser flows. And when using the condensate that has flowed through the condensate line as the gland steam of the steam turbine to spray and cool the steam, components of seawater such as chlorine and sodium that may be contained in the gland steam may mix into the passenger compartment through the gland. As a result, the turbine rotor housed inside the passenger compartment may be contaminated by the components of seawater.

Prior Art Documents

Patent Documents

[0003] [[ID=...]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the invention described in Patent Document 1, the turbine rotor is taken out from the steam turbine and immersed in a cleaning tank in which a cleaning solution is stored to clean the turbine rotor. In this case, not only the transfer operation of transferring the turbine rotor between the steam turbine and the cleaning tank is required, but also the operation of opening the passenger compartment of the steam turbine and the operation of closing the opened passenger compartment are required. A cleaning method that can clean the turbine rotor without performing these operations is desired.

[0005] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a method for cleaning a steam turbine that can clean the steam turbine without opening the passenger compartment of the steam turbine. [Means for solving the problem]

[0006] A steam turbine cleaning method according to at least one embodiment of the present disclosure is: A method for cleaning a steam turbine comprising a turbine rotor and a turbine casing having a chamber for rotatably housing the turbine rotor, A cleaning fluid supply step includes supplying cleaning fluid to the vehicle compartment to a predetermined height or higher so that a portion of the turbine rotor is submerged, A cleaning step of cleaning the inside of the vehicle compartment with the cleaning solution, The system includes a cleaning fluid discharge step, which involves discharging the cleaning fluid used to clean the inside of the vehicle compartment to the outside of the vehicle compartment. [Effects of the Invention]

[0007] According to at least one embodiment of the present disclosure, a method for cleaning a steam turbine is provided that allows the steam turbine to be cleaned without opening the casing of the steam turbine. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a turbine system equipped with a steam turbine, which is the target of cleaning in a steam turbine cleaning method according to one embodiment of the present disclosure. [Figure 2] This is a schematic cross-sectional view along the axial direction of a steam turbine that is the target of cleaning in a steam turbine cleaning method according to one embodiment of the present disclosure. [Figure 3] This is a flowchart showing an example of a steam turbine cleaning method according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described or shown in the drawings as embodiments are not intended to limit the scope of this disclosure, but are merely illustrative examples.

[0010] (Turbine system) Figure 1 is a schematic diagram of a turbine system 10 comprising a steam turbine 1, which is the target of a steam turbine 1 cleaning method according to one embodiment of the present disclosure. As shown in Figure 1, the turbine system 10 comprises a high-pressure turbine 11 configured to receive high-pressure steam, an intermediate-pressure turbine 12 configured to receive intermediate-pressure steam, a low-pressure turbine 13 configured to receive low-pressure steam, a condenser 14 configured to cool the steam discharged from the low-pressure turbine 13 and return it to water, and a drum 15 for separating water and saturated steam. Intermediate-pressure steam has a lower pressure than high-pressure steam, and low-pressure steam has a lower pressure than intermediate-pressure steam.

[0011] The condenser 14 has a cooling pipe 141 through which seawater SW flows. The condenser 14 is configured to exchange heat between the seawater SW flowing through the cooling pipe 141 located inside the condenser 14 and the steam introduced into the condenser 14. The condenser 14 cools and condenses the steam introduced into the condenser 14 with the seawater SW flowing through the cooling pipe 141, thereby returning it to water. The turbine system 10 includes a condensate line 100 through which the water (condensate) condensed in the condenser 14 flows.

[0012] The drum 15 includes a high-pressure side drum 151 for separating water from high-pressure steam, an intermediate-pressure side drum 152 for separating water from intermediate-pressure steam, and a low-pressure side drum 153 for separating water from low-pressure steam. These drums 15 (151, 152, 153) are connected to the condensate line 100.

[0013] The turbine system 10 includes a high-pressure steam introduction line 16 for guiding high-pressure steam from the high-pressure drum 151 to the high-pressure steam inlet 111 of the high-pressure turbine 11, an intermediate-pressure steam introduction line 17 for guiding intermediate-pressure steam from the intermediate-pressure drum 152 to the intermediate-pressure steam inlet 121 of the intermediate-pressure turbine 12, and a low-pressure steam introduction line 18 for guiding low-pressure steam from the low-pressure drum 153 to the low-pressure steam inlet 131 of the low-pressure turbine 13. Heaters (not shown) for heating the steam may be provided in the high-pressure steam introduction line 16, the intermediate-pressure steam introduction line 17, and the low-pressure steam introduction line 18.

[0014] In the illustrated embodiment, the turbine system 10 includes a crossover pipe 19 that leads a steam outlet 122 for discharging steam that has rotated the intermediate-pressure turbine 12 to the outside of the intermediate-pressure turbine 12 to a low-pressure steam inlet 131 of the low-pressure turbine 13.

[0015] In the illustrated embodiment, the turbine system 10 includes a high- and intermediate-pressure turbine 1A, which integrates the casings 4 of a high-pressure turbine 11 and an intermediate-pressure turbine 12. In the illustrated embodiment, the turbine system 10 also integrates the casings of a low-pressure turbine 13 and a condenser 14. Hereinafter, the high- and intermediate-pressure turbine 1A will be described as the steam turbine 1 to be cleaned in the steam turbine cleaning method for steam turbine 1, but the steam turbine cleaning method for steam turbine 1 of this disclosure is applicable not only to the high- and intermediate-pressure turbine 1A but also to other steam turbines and single-configuration steam turbines that are not integrated with a condenser.

[0016] In the illustrated embodiment, the rotating shaft portion 21 of the turbine rotor 2 passes through the high- and intermediate-pressure turbine 1A and the low-pressure turbine 13 along the axial direction. Glands 5 (5A, 5B) are formed at each of the shaft ends of the high- and intermediate-pressure turbine 1A. Glands 5C, 5D are formed at each of the shaft ends of the low-pressure turbine 13. Here, the glands are shaft seal mechanisms that suppress steam leakage and atmospheric inflow through the radial gap between the casing and the turbine rotor 2, which is formed in the portion of the steam turbine casing that the turbine rotor 2 penetrates. Seal steam (gland steam) is supplied to this shaft seal mechanism.

[0017] In the illustrated embodiment, the gland steam supplied to glands 5A and 5B is steam whose temperature has been reduced by spraying water extracted from the condensate line 100 onto the high-pressure steam extracted from the high-pressure steam introduction line 16 in the spraying section 101. The gland steam supplied to glands 5C and 5D is steam whose temperature has been reduced even further than the gland steam supplied to glands 5A and 5B by spraying water extracted from the condensate line 100 onto the steam whose temperature has been reduced in the spraying section 101 in the spraying section 102. The turbine system 10 has steam lines for leading steam from the spraying section 101 to glands 5A and 5B, respectively, and steam lines for leading steam from the spraying section 102 to glands 5C and 5D, respectively.

[0018] When seawater SW is used to cool the steam in the condenser 14, if damage such as holes occurs in the cooling pipe 141 due to long-term operation, there is a risk that seawater may enter the condensate line 100 through which the condensed condensate in the condenser 14 flows. Furthermore, when steam that has been cooled by spraying the condensate flowing through the condensate line 100 is used as gland steam, there is a risk that components of seawater, such as chlorine and sodium, that may be contained in the gland steam may enter the casing 3 of the steam turbine 1 through the gland 5. As a result, there is a risk that the turbine rotor 2 housed inside the casing 3 may be contaminated by the components of seawater.

[0019] FIG. 2 is a schematic cross-sectional view along the axial direction of a steam turbine 1 (high and intermediate pressure turbine 1A) which is a cleaning target of a cleaning method of a steam turbine 1 according to an embodiment of the present disclosure. As shown in FIG. 2, the steam turbine 1 (high and intermediate pressure turbine 1A) includes a turbine rotor 2 and a turbine casing 4 having a chamber 3 that rotatably houses the turbine rotor 2.

[0020] Hereinafter, the direction in which the central axis CA of the turbine rotor 2 extends is defined as the axial direction of the turbine rotor 2 (steam turbine 1). One side in the axial direction of the turbine rotor 2 on the side where the high-pressure turbine 11 is located with respect to the intermediate-pressure turbine 12 is defined as the first side, and the other side in the axial direction of the turbine rotor 2 is defined as the second side. Above the central axis CA of the turbine casing 4 is defined as the upper half of the turbine casing 4, and below the central axis CA of the turbine casing 4 is defined as the lower half of the turbine casing 4. Sometimes, the upper side of the central axis CA is referred to as the upper half side, and the lower side of the central axis CA is referred to as the lower half side.

[0021] In the embodiment shown in FIG. 2, the turbine rotor 2 includes a rotating shaft portion 21, a high-pressure side disk portion 22 that supports the high-pressure side turbine moving blades 11A, and an intermediate-pressure side disk portion 23 that supports the intermediate-pressure side turbine moving blades 12A. The rotating shaft portion 21 includes a high-pressure side insertion portion 24 that passes through a shaft hole 420 formed in an end portion (wall portion) 42 on the first side of the turbine casing 4, and an intermediate-pressure side insertion portion 25 that passes through a shaft hole 430 formed in an end portion (wall portion) 43 on the second side of the turbine casing 4. The high-pressure side insertion portion 24 is formed to have a smaller diameter than the high-pressure side disk portion 22. The intermediate-pressure side insertion portion 25 is formed to have a smaller diameter than the intermediate-pressure side disk portion 23.

[0022] As shown in Figure 2, the turbine casing 4 has the high-pressure steam inlet 111, the medium-pressure steam inlet 121, and the steam outlet 122 described above. The turbine casing 4 also has a steam outlet 112 for discharging the steam that has rotated the turbine rotor 2 in the high-pressure turbine 11 to the outside of the high-pressure turbine 11. In the embodiment shown in Figure 2, of the steam outlet 112, high-pressure steam inlet 111, medium-pressure steam inlet 121, and steam outlet 122, the steam outlet 112 is formed on the first side, and the steam outlet 122 is formed on the second side. The high-pressure steam inlet 111 is formed on the first side, further than the medium-pressure steam inlet 121.

[0023] In the embodiment shown in Figure 2, the high-pressure steam inlet 111, the steam outlet 112, and the medium-pressure steam inlet 121 are each formed in the lower half of the turbine casing 4 and open in a direction oriented vertically downward. In contrast, the steam outlet 122 connected to the crossover pipe 19 is formed in the upper half of the turbine casing 4 and opens in a direction oriented vertically upward.

[0024] The low-pressure steam inlet 131 of the low-pressure turbine 13, which is connected to the crossover pipe 19, is located above the central axis CA of the turbine casing 4. The crossover pipe 19 is located above the central axis CA from one end connected to the steam outlet 112 to the other end connected to the low-pressure steam inlet 131. In the embodiment shown in Figure 1, the low-pressure steam inlet 131 is located above the steam outlet 112. The crossover pipe 19 is located above the steam outlet 112 from one end connected to the steam outlet 112 to the other end connected to the low-pressure steam inlet 131.

[0025] In the embodiment shown in Figure 2, the vehicle compartment 3 includes a high-pressure side annular passage 113, a high-pressure side steam introduction passage 114, a high-pressure side steam discharge passage 115, a high-pressure side leak passage 116, an intermediate-pressure side annular passage 123, an intermediate-pressure side steam introduction passage 124, an intermediate-pressure side steam discharge passage 125, and an intermediate-pressure side leak passage 126.

[0026] The high-pressure side annular passage 113 and the medium-pressure side annular passage 123 are annular spaces formed between the inner surface of the turbine casing 4 and the outer surfaces of the disk portions 22 and 23 of the turbine rotor 2, extending along the axial direction of the turbine rotor 2. In the high-pressure side annular passage 113, high-pressure side turbine rotor blades 11A and high-pressure side turbine stator blades 11B, which are located upstream (second side) of the high-pressure steam flow direction from the high-pressure side turbine rotor blades 11A, are alternately arranged at intervals along the axial direction of the turbine rotor 2. The high-pressure side turbine rotor blades 11A are supported on the outer surface of the disk portion 22 of the turbine rotor 2 that defines the high-pressure side annular passage 113, and the high-pressure side turbine stator blades 11B are supported on the inner surface of the turbine casing 4 that defines the high-pressure side annular passage 113.

[0027] In the intermediate-pressure annular flow path 123, intermediate-pressure turbine rotor blades 12A and intermediate-pressure turbine stator blades 12B, which are located upstream (first side) of the intermediate-pressure steam flow direction relative to the intermediate-pressure turbine rotor blades 12A, are alternately arranged at intervals in the axial direction of the turbine rotor 2. The intermediate-pressure turbine rotor blades 12A are supported on the outer surface of the disk portion 23 of the turbine rotor 2 that defines the intermediate-pressure annular flow path 123, and the intermediate-pressure turbine stator blades 12B are supported on the inner surface of the turbine casing 4 that defines the intermediate-pressure annular flow path 123.

[0028] The high-pressure steam introduction channel 114 is a channel for guiding high-pressure steam from the high-pressure steam inlet 111 to the high-pressure annular channel 113. One side of the high-pressure steam introduction channel 114 is connected to the high-pressure steam inlet 111, and the other side is connected to the second end of the high-pressure annular channel 113. The high-pressure steam discharge channel 115 is a channel for guiding steam that has passed through the high-pressure turbine blades 11A to the steam discharge port 112. One side of the high-pressure steam discharge channel 115 is connected to the first end of the high-pressure annular channel 113, and the other side is connected to the steam discharge port 112.

[0029] The high-pressure side leak passage 116 is a passage through which steam leaking from the high-pressure side steam inlet passage 114 or the high-pressure side steam outlet passage 115 (high-pressure side steam outlet passage 115 in the illustrated example) flows in. The high-pressure side steam outlet passage 115 is in communication with the gland (high-pressure side gland) 5A formed at the first end of the steam turbine 1.

[0030] The intermediate-pressure steam introduction channel 124 is a channel for guiding intermediate-pressure steam from the intermediate-pressure steam inlet 121 to the intermediate-pressure annular channel 123. One side of the intermediate-pressure steam introduction channel 124 is connected to the intermediate-pressure steam inlet 121, and the other side is connected to the first end of the intermediate-pressure annular channel 123. The intermediate-pressure steam discharge channel 125 is a channel for guiding steam that has passed through the intermediate-pressure turbine blades 12A to the steam discharge port 122. One side of the intermediate-pressure steam discharge channel 125 is connected to the second end of the intermediate-pressure annular channel 123, and the other side is connected to the steam discharge port 122.

[0031] The intermediate-pressure side leak passage 126 is a passage through which steam leaking from the intermediate-pressure side steam inlet passage 124 or the intermediate-pressure side steam outlet passage 125 (in the illustrated example, the intermediate-pressure side steam inlet passage 124) flows in. The intermediate-pressure side steam outlet passage 125 is in communication with the gland (intermediate-pressure side gland) 5B formed at the second end of the steam turbine 1.

[0032] The high-pressure side gland 5A is a portion of the axial radial gap formed between the high-pressure side insertion portion 24 and the shaft hole 420, and its radial gap is larger than the shaft seal portions formed on both sides of the high-pressure side gland 5A in the axial direction. The medium-pressure side gland 5B is a portion of the axial radial gap formed between the medium-pressure side insertion portion 25 and the shaft hole 430, and its radial gap is larger than the shaft seal portions formed on both sides of the medium-pressure side gland 5B in the axial direction.

[0033] (Method for cleaning steam turbines) Figure 3 is a flow chart showing an example of a cleaning method for a steam turbine 1 according to one embodiment of the present disclosure. A cleaning method for a steam turbine 1 according to several embodiments comprises a cleaning fluid supply step S1, a cleaning step S2, and a cleaning fluid discharge step S3, as shown in Figure 3. In the cleaning fluid supply step S1, cleaning fluid is supplied to the casing 3 to a predetermined height (PH, see Figure 2) or higher, where a portion of the turbine rotor 2 is submerged. In the cleaning step S2, the inside of the casing 3 is cleaned with the cleaning fluid. In the cleaning fluid discharge step S3, the cleaning fluid used to clean the inside of the casing 3 is discharged to the outside of the casing 3. Here, the predetermined height where a portion of the turbine rotor 2 is submerged is preferably a height that allows at least the high-pressure side turbine blade 11A and the intermediate-pressure side turbine blade 12A, located vertically downward (at the 6 o'clock position), to be submerged in the cleaning fluid. The cleaning fluid is preferably water that does not contain salt (fresh water).

[0034] According to the method for cleaning the steam turbine 1, cleaning fluid is supplied to a predetermined height or higher so that a portion of the turbine rotor 2 in the casing 3 is submerged (cleaning fluid supply step S1), and the inside of the casing 3 and the turbine rotor 2 can be cleaned by immersing them in the cleaning fluid (cleaning step S2). The cleaning fluid that has cleaned the inside of the casing 3 is then discharged to the outside of the casing 3 (cleaning fluid discharge step S3). According to the method for cleaning the steam turbine 1, the series of steps S1 to S3 for cleaning the steam turbine 1 can be performed without opening the casing 3, thus making the cleaning work of the steam turbine 1 easier.

[0035] (Vehicle interior side opening / closing valve) In the cleaning fluid supply step S1 and cleaning step S2 of the steam turbine 1 cleaning method according to some embodiments, the cabin-side on-off valves 7 (7A to 7E) connected to the cabin-side cleaning fluid discharge lines 6 (6A to 6E) that can discharge the cleaning fluid from the cabin 3 are closed. The cleaning fluid discharge step S3 described above is performed by opening the cabin-side on-off valves 7 (7A to 7E). Each of the cabin-side on-off valves 7 (7A to 7E) is connected to the cabin-side cleaning fluid discharge line 6 (6A to 6E) to which the cabin-side on-off valve 7 corresponds.

[0036] The cabin-side cleaning fluid discharge lines 6 (6A to 6E) are configured to be positioned lower as they move away from one end connected to the lower half of the cabin 3 (towards the other end), so that the cleaning fluid flowing in from the cabin (lower half cabin) 3 defined by the lower half of the turbine casing 4 can flow down. The cabin-side on-off valves 7 (7A to 7E) only need to have a valve body capable of opening and closing the cabin-side cleaning fluid discharge lines 6 (6A to 6E), and may also be flow control valves.

[0037] In the illustrated embodiment, one end of the cabin-side cleaning fluid discharge line 6A is connected to the intermediate-pressure side steam discharge channel 125. One end of the cabin-side cleaning fluid discharge line 6B is connected to the intermediate-pressure side steam introduction channel 124 (in the illustrated example, the intermediate-pressure steam inlet 121, which is the end of the intermediate-pressure side steam introduction channel 124). One end of the cabin-side cleaning fluid discharge line 6C is connected to the intermediate-pressure side leak channel 126. One end of the cabin-side cleaning fluid discharge line 6D is connected to the high-pressure side steam discharge channel 115 (in the illustrated example, the steam outlet 112, which is the end of the high-pressure side steam discharge channel 115). One end of the cabin-side cleaning fluid discharge line 6E is connected to the high-pressure side leak channel 116. Note that the cabin-side cleaning fluid discharge line 6 may also include one end connected to the high-pressure side steam introduction channel 114 (in the illustrated example, the high-pressure steam inlet 111, which is the end of the high-pressure side steam introduction channel 114).

[0038] By closing the cabin-side shut-off valves 7 (7A-7E) in the cleaning fluid supply step S1 and the cleaning step S2, the outflow of cleaning fluid from the cabin 3 via the cabin-side cleaning fluid discharge line 6 (6A-6E) can be suppressed, and the cleaning fluid can be accumulated inside the cabin 3. In this case, the work of accumulating cleaning fluid in the cabin 3 to a predetermined height or higher becomes easier, thus simplifying the cleaning of the steam turbine 1.

[0039] In the cleaning fluid discharge step S3, by opening the cabin-side on-off valves 7 (7A-7E), the cleaning fluid used to clean the inside of cabin 3 can be discharged to the outside of cabin 3 through the cabin-side cleaning fluid discharge lines 6 (6A-6E). The cleaning fluid flows down the cabin-side cleaning fluid discharge lines 6 (6A-6E). In this case, the operation of discharging the cleaning fluid from cabin 3 becomes easier, and thus the cleaning operation of the steam turbine 1 becomes easier.

[0040] Furthermore, the cabin-side cleaning fluid discharge line 6 is preferably an internal flow path in the turbine casing 4 configured for the flow of steam, drain water, etc., or existing piping in the steam turbine 1. The cabin-side on-off valve 7 is preferably an existing device installed in the existing piping. Also, when cleaning a part of the steam turbine 1, for example, either the high-pressure turbine 11 or the intermediate-pressure turbine 12, it is sufficient for the cleaning fluid to accumulate in the area of ​​the cabin 3 that is to be cleaned. The cabin-side on-off valve 7 that opens and closes the cabin-side cleaning fluid discharge line 6 connected to the area of ​​the cabin 3 that is to be cleaned does not have to be the object to be opened and closed in the steam turbine 1 cleaning method.

[0041] (Gland-side shut-off valve) In the cleaning fluid supply step S1 of a steam turbine cleaning method according to several embodiments, cleaning fluid is supplied until it leaks from at least one gland 5 (5A, 5B) formed between the rotating shaft portion 21 of the turbine rotor 2 and the turbine casing 4, and configured to introduce gland steam. Here, until the cleaning fluid leaks from the gland 5 (5A, 5B) includes not only direct leakage of the cleaning fluid from the gland 5 (5A, 5B) to the outside of the turbine casing 4, but also leakage via the gland-side cleaning fluid discharge lines 8 (8A, 8B).

[0042] By supplying cleaning fluid to the ground 5 to a height above which it leaks, some of the cleaning fluid can flow from the vehicle compartment 3 into the ground 5, immersing the inside of the ground 5 in the cleaning fluid. In other words, the cleaning fluid can also clean the inside of the ground 5, which is highly likely to be severely contaminated with seawater.

[0043] In the cleaning step S1 and cleaning step S2 of the steam turbine 1 cleaning method according to some embodiments, the gland-side on-off valves 9 (9A, 9B) connected to the gland-side cleaning fluid discharge lines 8 (8A, 8B) that can discharge the cleaning fluid from the gland 5 are open.

[0044] The gland-side cleaning fluid discharge lines 8 (8A, 8B) are configured to be positioned lower as they move away from one end connected to the gland 5 (towards the other end), so that the cleaning fluid flowing in from the lower half of the gland 5 (5A, 5B), which is defined by the lower half of the turbine casing 4, can flow down. The gland-side on-off valves 9 (9A, 9B) only need to have a valve body capable of opening and closing the gland-side cleaning fluid discharge lines 8 (8A, 8B), and may also be flow control valves.

[0045] The gland-side cleaning fluid discharge line 8A has one end connected to the lower half of gland 5A, and the other end connected to the gland-side on-off valve 9A. The gland-side cleaning fluid discharge line 8B has one end connected to the lower half of gland 5B, and the other end connected to the gland-side on-off valve 9B.

[0046] In the cleaning fluid supply step S1 and the cleaning step S2, by opening the gland-side shut-off valves 9 (9A, 9B), the cleaning fluid that has flowed from the casing 3 into the gland 5 can be discharged to the outside of the steam turbine 1 through the gland-side cleaning fluid discharge lines 8 (8A, 8B). The cleaning fluid flows down the gland-side cleaning fluid discharge lines 8 (8A, 8B). In this case, the discharge of cleaning fluid from the gland 5 becomes easier, thus simplifying the cleaning of the steam turbine 1. Here, by setting the flow direction of the cleaning fluid in the cleaning fluid supply step S1 and the cleaning step S2 to flow from the casing 3 towards the gland 5, the inflow of seawater components from the gland 5 into the casing 3 during the cleaning of the steam turbine 1 can be suppressed.

[0047] Furthermore, the gland-side cleaning fluid discharge line 8 is preferably an internal flow path of the turbine casing 4 configured for the flow of drain water, etc., or existing piping in the steam turbine 1. The gland-side on-off valve 9 is preferably an existing device installed in the existing piping.

[0048] (Turbine rotor rotation)

[0049] In the cleaning step S2 of a steam turbine 1 cleaning method according to several embodiments, the turbine rotor 2 is rotated to change the portion of the turbine rotor 2 immersed in the cleaning fluid. For example, in cleaning step S2, the turbine rotor 2 is rotated by a predetermined angle at regular intervals to change the circumferential position of the turbine rotor 2. The rotation of the turbine rotor 2 in cleaning step S2 is continued until the turbine rotor 2 has completed at least one full rotation. By rotating the turbine rotor 2 in this way and changing the portion of the turbine rotor 2 immersed in the cleaning fluid, the entire circumference of the turbine rotor 2 can be cleaned with the cleaning fluid.

[0050] In the cleaning step S2 of the steam turbine 1 cleaning method according to several embodiments, cleaning fluid is supplied to the casing 3, and the cleaning fluid used to clean the inside of the casing 3 is discharged to the outside of the casing 3 (step S20). Here, it is preferable that the cleaning fluid discharge in cleaning step S2 is carried out through the gland side cleaning fluid discharge line 8 described above. It is preferable that the cleaning fluid discharge from the inside to the outside of the casing 3 in cleaning step S2 be carried out continuously, but it may also be carried out intermittently.

[0051] In cleaning step S2, cleaning fluid is supplied to the casing 3 and drained from the casing 3, replacing the cleaning fluid inside the casing 3. This prevents an increase in the concentration of seawater components in the cleaning fluid inside the casing 3, which would reduce the cleaning effect. As a result, the cleaning effect of the cleaning fluid in cleaning step S2 can be maintained, allowing for effective cleaning of the inside of the casing 3 and the turbine rotor 2.

[0052] In a cleaning method for a steam turbine 1 according to several embodiments, cleaning step S2 includes a salinity acquisition step S21 and a rotor rotation step S22. In the salinity acquisition step S21, the salinity of the cleaning fluid discharged to the outside of the casing 3 is acquired using a salinity meter or the like. Here, the cleaning fluid from which the salinity is acquired is preferably the cleaning fluid discharged through the ground-side cleaning fluid discharge line 8 described above. The acquisition of the salinity of the cleaning fluid may be repeated at regular intervals, or the changes in salinity as they change moment by moment may be acquired continuously.

[0053] In the rotor rotation step S22, when the salt concentration obtained in the salt concentration acquisition step S21 falls below a predetermined concentration, the turbine rotor 2 is rotated to change the portion of the turbine rotor 2 immersed in the cleaning fluid. The rotor rotation step S22 is performed until the turbine rotor 2 has completed at least one rotation.

[0054] When the salt concentration of the cleaning fluid discharged to the outside of the casing 3 falls below a predetermined concentration, the portion of the turbine rotor 2 immersed in the cleaning fluid can be considered to have been sufficiently cleaned. When the salt concentration of the cleaning fluid discharged to the outside of the casing 3 falls below a predetermined concentration, the turbine rotor 2 is rotated, changing the portion of the turbine rotor 2 immersed in the cleaning fluid, thereby ensuring that the entire circumference of the turbine rotor 2 is thoroughly cleaned with the cleaning fluid. The salt concentration acquisition step S21 and the rotor rotation step S22 are preferably performed in combination with step S20.

[0055] (Method of supplying cleaning solution)

[0056] In the cleaning fluid supply step S1 of a steam turbine 1 cleaning method according to some embodiments, the cleaning fluid W (see Figure 2) is supplied through the balance hole 41 (41A or 41B) of the steam turbine 1, or by removing at least a portion of the crossover pipe 19.

[0057] By supplying cleaning fluid to the steam turbine 1 through the existing balance hole 41 and crossover pipe 19, cleaning fluid can be supplied to the casing 3 without having to perform time-consuming tasks such as opening the casing 3 in the cleaning fluid supply step S1, thus simplifying the cleaning operation of the steam turbine 1.

[0058] The balance holes 41 are formed in the wall surfaces 421 and 431 that face the end faces 221 and 231 of the disc portions 22 and 23 that support the turbine blades 11A and 11B of the turbine rotor 2, with an axial gap in between. The balance holes 41 penetrate the wall portions 42 and 43 of the turbine casing 4 having the wall surfaces 421 and 431 in the axial direction, and are through holes that connect the axial gap to the outside of the wall portions 42 and 43. Balance hole 41A is formed in the first end (wall portion) 42 of the turbine casing 4 where the gland 5A is formed. Balance hole 41B is formed in the second end (wall portion) 43 of the turbine casing 4 where the gland 5B is formed. Either balance hole 41A or balance hole 41B may be used to supply cleaning fluid to the casing 3, or both balance holes 41A and balance hole 41B may be used. The cleaning fluid is supplied to the casing 3 using a balance hole 41 (41A or 41B) formed in the upper half of the turbine casing 4.

[0059] Since the balance hole 41 opens near the ground 5 in the vehicle compartment 3, the cleaning fluid supplied to the interior of the vehicle compartment 3 through the balance hole 41 easily flows from the vehicle compartment 3 to the ground 5. By supplying the cleaning fluid through the balance hole 41, the ground 5 can be effectively cleaned with the cleaning fluid.

[0060] By removing at least a portion of the crossover pipe 19, the cleaning fluid can be supplied through the steam outlet 122 or the remaining portion of the crossover pipe 19 connected to the steam outlet 122. Since the crossover pipe 19 and the opening connected to it (steam outlet 122) have a larger diameter than the balance hole 41, it is possible to increase the flow rate of the cleaning fluid supplied to the inside of the casing 3 compared to the balance hole 41. The cleaning fluid supplied to the inside of the casing 3 through the crossover pipe 19 flows easily toward the turbine rotor 2 located in the steam path within the casing 3. By supplying the cleaning fluid through the crossover pipe 19, the turbine rotor 2 can be effectively cleaned with the cleaning fluid.

[0061] In this specification, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" shall not only describe such arrangements strictly, but also describe states of relative displacement with tolerances or angles or distances that allow for the same function to be achieved. For example, expressions such as "identical," "equal," and "homogeneous" that describe things being in an equal state not only describe a state of being strictly equal, but also describe a state in which there is a tolerance or a difference that is sufficient to achieve the same function. Furthermore, in this specification, expressions describing shapes such as quadrilaterals and cylindrical shapes shall not only represent geometrically precise quadrilaterals and cylindrical shapes, but also shapes that include uneven surfaces, chamfered surfaces, etc., to the extent that the same effect can be achieved. Furthermore, in this specification, the expressions “equipment,” “includes,” or “possess” of a component are not exclusive expressions that exclude the existence of other components.

[0062] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0063] The contents described in some of the embodiments above can be understood, for example, as follows:

[0064] 1) A method for cleaning a steam turbine (1) according to at least one embodiment of the present disclosure is: A method for cleaning a steam turbine (1) comprising a turbine rotor (2) and a turbine casing (4) having a chamber (3) that rotatably houses the turbine rotor (2), A cleaning fluid supply step (S1) is to supply cleaning fluid to the casing (3) to a predetermined height or higher so that a portion of the turbine rotor (2) is submerged, A cleaning step (S2) is performed to clean the inside of the vehicle compartment (3) with the cleaning solution, The system includes a cleaning fluid discharge step (S3) in which the cleaning fluid used to clean the inside of the vehicle compartment (3) is discharged to the outside of the vehicle compartment (3).

[0065] According to method 1) above, the cleaning fluid is supplied to a predetermined height or higher so that a portion of the turbine rotor (2) in the casing (3) is submerged, and the inside of the casing (3) and the turbine rotor (2) can be cleaned by immersing them in the cleaning fluid. The cleaning fluid that has cleaned the inside of the casing (3) is then discharged to the outside of the casing (3). According to method 1) above, the series of steps for cleaning the steam turbine (1) can be carried out without opening the casing (3), making the cleaning work of the steam turbine (1) easier.

[0066] 2) In some embodiments, the method for cleaning the steam turbine (1) described in 1) above, The cleaning fluid discharge step (S3) is performed as follows: This is done by opening the on-off valve on the passenger compartment side, which is connected to the passenger compartment side cleaning fluid discharge line that can discharge the cleaning fluid from the passenger compartment (3).

[0067] According to the method described in 2) above, by opening the cabin-side shut-off valve in the cleaning fluid discharge step (S3), the cleaning fluid used to clean the inside of the cabin (3) can be discharged to the outside of the cabin (3) through the cabin-side cleaning fluid discharge line. In this case, the operation of discharging the cleaning fluid from the cabin (3) becomes easier, and thus the cleaning operation of the steam turbine (1) becomes easier.

[0068] 3) In some embodiments, the method for cleaning the steam turbine (1) described in 2) above, In the cleaning fluid supply step (S1) and the cleaning step (S2), The aforementioned vehicle compartment-side opening / closing valve is closed.

[0069] According to method 3) above, by closing the on-off valve on the casing side in the cleaning fluid supply step (S1) and the cleaning step (S2), the outflow of cleaning fluid from the casing (3) via the cleaning fluid discharge line on the casing side can be suppressed, and the cleaning fluid can be accumulated inside the casing (3). In this case, the work of accumulating cleaning fluid in the casing (3) to a predetermined height or higher becomes easier, thus making the cleaning work of the steam turbine (1) easier.

[0070] 4) In some embodiments, a method for cleaning a steam turbine (1) as described in any of 1) to 3) above, In the cleaning fluid supply step (S1), The cleaning fluid is supplied until it leaks from at least one gland (5) formed between the rotating shaft portion (21) of the turbine rotor (2) and the turbine casing (4), which is configured to allow gland steam to be introduced.

[0071] When seawater is used to cool the steam in the condenser (14), if damage such as holes occurs in the cooling pipes due to long-term operation, there is a risk that seawater may enter the condensate line (100) through which the condensed condensate in the condenser (14) flows. Furthermore, when steam that has been cooled by spraying the condensate flowing through the condensate line (100) is used as gland steam, there is a risk that components of seawater that may be contained in the gland steam may enter the casing (3) through the gland (5). According to the method of 4) above, by supplying the cleaning solution to a height above the height at which the cleaning solution leaks from the gland (5), some of the cleaning solution can flow from the casing (3) into the gland (5), and the inside of the gland (5) can also be immersed in the cleaning solution. In other words, the inside of the gland (5), which is highly likely to be seriously contaminated with seawater, can also be cleaned with the cleaning solution.

[0072] 5) In some embodiments, the method for cleaning the steam turbine (1) described in 4) above, In the cleaning fluid supply step (S1) and the cleaning step (S2), The gland-side on / off valve (9), which is connected to the gland-side cleaning fluid discharge line (8) that can discharge the cleaning fluid from the gland (5), is open.

[0073] According to the method described in 5) above, by opening the gland-side shut-off valve (9) in the cleaning fluid supply step (S1) and the cleaning step (S2), the cleaning fluid that has flowed from the casing (3) into the gland (5) can be discharged to the outside of the steam turbine (1) through the gland-side cleaning fluid discharge line (8). In this case, the operation of discharging the cleaning fluid from the gland (5) becomes easier, and thus the cleaning operation of the steam turbine (1) becomes easier. Here, by setting the flow direction of the cleaning fluid in the cleaning fluid supply step (S1) and the cleaning step (S2) to be from the casing (3) to the gland (5), the inflow of seawater components from the gland (5) into the casing (3) during the cleaning of the steam turbine (1) can be suppressed.

[0074] 6) In some embodiments, a method for cleaning a steam turbine (1) as described in any of 1) to 5) above, In the cleaning step (S2), the turbine rotor (2) is rotated to change the portion of the turbine rotor (2) that is immersed in the cleaning fluid.

[0075] According to the method described in 6) above, the entire circumference of the turbine rotor (2) can be cleaned with the cleaning solution by rotating the turbine rotor (2) and changing the part of the turbine rotor (2) that is immersed in the cleaning solution.

[0076] 7) In some embodiments, a method for cleaning a steam turbine (1) as described in any of 1) to 6) above, In the aforementioned cleaning step (S2), The cleaning solution is supplied to the vehicle compartment (3), and the cleaning solution used to clean the inside of the vehicle compartment (3) is then discharged to the outside of the vehicle compartment (3).

[0077] According to the method described in 7) above, in the cleaning step (S2), cleaning fluid is supplied to the casing (3) and the cleaning fluid is discharged from the casing (3), and by replacing the cleaning fluid inside the casing (3), it is possible to suppress the increase in the concentration of seawater components in the cleaning fluid inside the casing (3) and the decrease in cleaning effect. As a result, the cleaning effect of the cleaning fluid in the cleaning step (S2) can be maintained, and the inside of the casing (3) and the turbine rotor (2) can be effectively cleaned.

[0078] 8) In some embodiments, the method for cleaning the steam turbine (1) described in 7) above, The aforementioned cleaning step (S2) is, A salt concentration acquisition step (S21) is performed to acquire the salt concentration of the cleaning solution discharged to the outside of the vehicle compartment (3), The process includes, when the salt concentration obtained in the salt concentration acquisition step (S21) falls below a predetermined concentration, a rotor rotation step (S22) in which the turbine rotor (2) is rotated to change the portion of the turbine rotor (2) that is immersed in the cleaning liquid.

[0079] According to the method described in 8) above, when the salt concentration of the cleaning fluid discharged outside the casing (3) falls below a predetermined concentration, the portion of the turbine rotor (2) immersed in the cleaning fluid can be considered to have been sufficiently cleaned. When the salt concentration of the cleaning fluid discharged outside the casing (3) falls below a predetermined concentration, the turbine rotor (2) is rotated to change the portion of the turbine rotor (2) immersed in the cleaning fluid, thereby ensuring that the entire circumference of the turbine rotor (2) is thoroughly cleaned with the cleaning fluid.

[0080] 9) In some embodiments, a method for cleaning a steam turbine (1) as described in any of 1) to 8) above, In the cleaning fluid supply step (S1), The cleaning fluid is supplied through the balance hole (41) of the steam turbine (1) or by removing at least a portion of the crossover pipe (19).

[0081] According to the method described in 9) above, by supplying cleaning fluid to the steam turbine (1) through the existing balance hole (41) and crossover pipe (19), cleaning fluid can be supplied to the casing (3) without having to perform time-consuming tasks such as opening the casing (3) in the cleaning fluid supply step (S1), thus simplifying the cleaning operation of the steam turbine (1).

[0082] 10) In some embodiments, the method for cleaning the steam turbine (1) described in 9) above, In the cleaning fluid supply step (S1), The cleaning fluid is supplied through the balance hole (41).

[0083] According to the method described in 10) above, since the balance hole (41) opens near the ground (5) in the vehicle compartment (3), the cleaning fluid supplied to the interior of the vehicle compartment (3) through the balance hole (41) can easily flow from the vehicle compartment (3) to the ground (5). By supplying the cleaning fluid through the balance hole (41), the ground (5) can be effectively cleaned with the cleaning fluid.

[0084] 11) In some embodiments, the method for cleaning the steam turbine (1) described in 9) above, In the cleaning fluid supply step (S1), The cleaning fluid is supplied by removing at least a portion of the crossover pipe (19).

[0085] According to the method described in 11) above, the crossover pipe (19) and the opening connected to the crossover pipe (19) (steam outlet 122) have a larger diameter than the balance hole (41), making it possible to increase the flow rate of the cleaning fluid supplied to the inside of the casing (3) compared to the balance hole (41). The cleaning fluid supplied to the inside of the casing (3) through the crossover pipe (19) flows more easily toward the turbine rotor (2) located in the steam path inside the casing (3). By supplying the cleaning fluid through the crossover pipe (19), the turbine rotor (2) can be effectively cleaned with the cleaning fluid. [Explanation of symbols]

[0086] 1. Steam Turbine 2 Turbine rotors 3 Cabin 4. Turbine casing 5 Grand 6. Washing fluid discharge line on the passenger compartment side 7. On / off valve on the passenger compartment side 8. Gland side cleaning fluid discharge line 9. Gland-side shut-off valve 10 Turbine Systems 11. High-pressure turbine 11A High-pressure side turbine blades 11B High-pressure side turbine stator blades 12. Intermediate pressure turbine 12A Intermediate-pressure side turbine blades 12B Intermediate pressure side turbine stator blades 13 Low-pressure turbine 14 Condenser 15 Drums 16. High-pressure steam introduction line 17. Medium-pressure steam introduction line 18 Low-pressure steam introduction line 19 Crossover tubes 21 Rotating shaft section 41 Balance Hole 100 Condensate Line 111 High-pressure steam inlet 112,122 Steam outlet 121 Medium-pressure steam inlet 131 Low-pressure steam inlet 141 Cooling pipe CA center axis S1 Cleaning solution supply step S2 Cleaning Step S21 Salt concentration acquisition step S22 Rotor rotation step S3 Cleaning solution discharge step

Claims

1. A method for cleaning a steam turbine comprising a turbine rotor and a turbine casing having a chamber for rotatably housing the turbine rotor, A cleaning fluid supply step includes supplying cleaning fluid to the vehicle compartment to a predetermined height or higher so that a portion of the turbine rotor is submerged, A cleaning step of cleaning the inside of the vehicle compartment with the cleaning solution, The system includes a cleaning fluid discharge step, which involves discharging the cleaning fluid used to clean the inside of the vehicle compartment to the outside of the vehicle compartment. A method for cleaning a steam turbine.

2. The cleaning liquid discharge step is, This is done by opening a vehicle compartment-side on / off valve connected to a vehicle compartment-side cleaning fluid discharge line that can discharge the cleaning fluid from the vehicle compartment. A method for cleaning a steam turbine according to claim 1.

3. In the above cleaning fluid supply step and the cleaning step, The aforementioned vehicle compartment side opening / closing valve is closed. The method for cleaning a steam turbine according to claim 2.

4. In the cleaning solution supply step, The cleaning fluid is supplied until it leaks from at least one gland formed between the rotating shaft portion of the turbine rotor and the turbine casing, which is configured to introduce gland steam. A method for cleaning a steam turbine according to any one of claims 1 to 3.

5. In the above cleaning fluid supply step and the cleaning step, The gland-side on / off valve connected to the gland-side cleaning fluid discharge line, which can discharge the cleaning fluid from the gland, is open. The method for cleaning a steam turbine according to claim 4.

6. In the cleaning step, the turbine rotor is rotated to change the portion of the turbine rotor that is immersed in the cleaning fluid. A method for cleaning a steam turbine according to any one of claims 1 to 3.

7. In the aforementioned cleaning step, The cleaning solution is supplied to the vehicle compartment, and the cleaning solution used to clean the inside of the vehicle compartment is discharged to the outside of the vehicle compartment. A method for cleaning a steam turbine according to any one of claims 1 to 3.

8. The aforementioned cleaning step is A salt concentration acquisition step to acquire the salt concentration of the cleaning solution discharged to the outside of the vehicle compartment, The method includes, when the salt concentration obtained in the salt concentration acquisition step falls below a predetermined concentration, a rotor rotation step in which the turbine rotor is rotated to change the portion of the turbine rotor immersed in the cleaning liquid, The method for cleaning a steam turbine according to claim 7.

9. In the cleaning solution supply step, The cleaning fluid is supplied through the balance hole of the steam turbine or by removing at least a portion of the crossover pipe. A method for cleaning a steam turbine according to any one of claims 1 to 3.

10. In the cleaning solution supply step, The cleaning fluid is supplied through the balance hole. The method for cleaning a steam turbine according to claim 9.

11. In the cleaning solution supply step, The cleaning fluid is supplied by removing at least a portion of the crossover pipe. The method for cleaning a steam turbine according to claim 9.

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