JP2019108835A - Steam turbine plant and its operation method - Google Patents

Abstract

To provide a steam turbine plant and its operation method capable of shortening a start time of a steam turbine.SOLUTION: A steam turbine plant includes a boiler generating steam from water. The plant further includes a first steam turbine rotated and driven by steam generated by the boiler, and heated or not heated by a reheater. Furthermore the plant includes a separation mechanism for separating first steam generated by the boiler and heated or not heated by the reheater into second steam of a temperature lower than the first steam and third steam of a temperature higher than the first steam, supplying the second steam to the neighborhood of a surface of a shaft rotor in the first steam turbine, and cooling the shaft rotor by the second steam.SELECTED DRAWING: Figure 1

Description

  Embodiments of the present invention relate to a steam turbine plant and its method of operation.

  As a prior art, the steam turbine plant which comprises a non-reheat cycle is demonstrated using FIG.

  FIG. 11 is a cross-sectional view showing a configuration example of a conventional steam turbine plant. The steam turbine plant of FIG. 11 includes a boiler 1, a steam turbine 2, a condenser 3, and a pump 4.

  The water 101 is conveyed by the pump 4 and flows into the boiler 1. The water 101 is heated by the boiler 1 and changes to high pressure steam 102. The heat source of the boiler 1 is, for example, fossil fuel or gas turbine exhaust gas. The high-pressure steam 102 generated from the water 101 in the boiler 1 flows into the steam turbine 2 and the high-pressure high-temperature steam expands while flowing to a low-pressure low-temperature steam, thereby rotationally driving an expander, which is an impeller.

  The steam turbine exhaust 103 flowing out of the steam turbine 2 is cooled by the condenser 3 and condensed into water 101. The cooling source of the condenser 3 is, for example, seawater. A generator (not shown) is connected to the rotating shaft (not shown) of the steam turbine 2 and the generator generates power using the shaft power generated by the expander. A regeneration cycle may be configured in which the water 101 is heated by a feed water heater using the bleed steam from the steam turbine 2.

  As another prior art, a steam turbine plant that constitutes a reheat cycle will be described with reference to FIG.

  FIG. 12 is a cross-sectional view showing another configuration example of a conventional steam turbine plant. The steam turbine plant of FIG. 12 includes a boiler 1, a condenser 3, a pump 4, a high pressure turbine 5, an intermediate pressure turbine 6, a low pressure turbine 7, and a reheater 8.

  The water 101 is conveyed by the pump 4 and flows into the boiler 1. The water 101 is heated by the boiler 1 and changes to high pressure steam 102. The heat source of the boiler 1 is, for example, fossil fuel or gas turbine exhaust gas. The high-pressure steam 102 generated from the water 101 in the boiler 1 flows into the high-pressure turbine 5, and the high-pressure high-temperature steam expands while flowing to a low-pressure low-temperature steam to rotationally drive an expander, which is an impeller.

  The high pressure turbine exhaust 104 flowing out of the high pressure turbine 5 flows into the reheater 8. The high pressure turbine exhaust 104 is heated by the reheater 8 and becomes the medium pressure steam 105. The heat source of the reheater 8 is, for example, fossil fuel or gas turbine exhaust. The medium pressure steam 105 flows into the medium pressure turbine 6, and the high-pressure and high-temperature steam is expanded to a low-pressure and low-temperature steam to circulate, thereby rotating an expander, which is an impeller.

  The medium pressure turbine exhaust 106 flowing out of the medium pressure turbine 6 flows into the low pressure turbine 7. The low pressure turbine 7 in FIG. 12 is a double flow turbine, and the inflowing medium pressure turbine exhaust 106 is branched in two opposite directions, and the high pressure and high temperature steam is expanded while flowing to a lower pressure and low temperature steam. Rotate certain 2 expanders.

  The two steams flowing out of the low pressure turbine 7 join together to form a low pressure turbine exhaust 107, which flows into the condenser 3, is cooled and condensed, and changes to water 101. The cooling source of the condenser 3 is, for example, seawater. A generator (not shown) is connected to a common rotating shaft (not shown) of the high pressure turbine 5, the intermediate pressure turbine 6 and the low pressure turbine 7, and power generation is carried out using the shaft power generated by the expander. The machine generates electricity.

  The rotating shafts of the high pressure turbine 5 and the medium pressure turbine 6 and the rotating shaft of the low pressure turbine 7 may be separated, and these rotating shafts may be connected to different generators to generate electric power. Further, although the high pressure turbine 5 and the intermediate pressure turbine 6 are integrated in FIG. 12, they may be separated. Also, a regeneration cycle may be configured to heat the water 101 with a feed water heater using the extracted steam from the high pressure turbine 5, the intermediate pressure turbine 6, and the low pressure turbine 7.

  Next, the high pressure turbine 5 and the intermediate pressure turbine 6 of FIG. 12 will be described with reference to FIGS. 13 and 14.

  FIG. 13 is a cross-sectional view showing the structure of a conventional steam turbine. The steam turbine of FIG. 13 is a high / medium pressure integrated steam turbine configured by a high pressure turbine 5 and an intermediate pressure turbine 6, and includes a shaft rotor 11, a high pressure inner casing 13, an outer casing 14 and a high pressure exhaust chamber 15. The medium pressure exhaust chamber 16, the main steam pipe 17, the reheat steam pipe 18, and the nozzle box 19 are provided. Although in FIG. 13 the shaft rotor 11 is not provided with a shaft hole, there is also a shaft rotor 11 provided with a shaft hole. FIG. 13 further shows a high-pressure first-stage rotor blade 21 which constitutes this high and medium-pressure turbine, an intermediate-pressure first-stage stator blade 22 and an intermediate-pressure first-stage rotor blade 23. The shaft rotor 11, high-pressure first-stage moving blades 21, medium-pressure first-stage moving blades 23, etc. constitute the rotor (rotating portion) of the steam turbine, and the high-pressure inner casing 13, outer casing 14, middle-pressure first-stage stator blades 22 etc. Constitute the stator (stationary part) of the steam turbine. The stator is provided to surround the rotor.

  The high-pressure steam 102 flows into the high-pressure turbine 5 from the main steam pipe 17 and reduces the pressure and the temperature to expand, and rotationally drives an impeller composed of the shaft rotor 11 and the moving blades. The high pressure steam 102 flows in the axial direction in the high pressure turbine 5, flows out from the high pressure exhaust chamber 15, flows into the reheater 8, and becomes the reheated steam 105.

  The reheated steam 105 flows from the reheated steam pipe 18 into the intermediate pressure turbine 6 and reduces the pressure and the temperature to expand, and rotationally drives an impeller composed of the shaft rotor 11 and the moving blades. The reheated steam 105 flows axially in the intermediate pressure turbine 6, flows out of the intermediate pressure exhaust chamber 16, and flows into the low pressure turbine 7.

  FIG. 14 is an enlarged cross-sectional view showing a structure of a conventional steam turbine, and more specifically, a cross-sectional view showing the vicinity of a steam inflow portion of the high / medium pressure turbine of FIG. FIG. 14 shows, in addition to the components shown in FIG. 13, a temperature sensor (thermocouple) 20, a high-pressure two-stage vane 24, and a high-pressure two-stage vane inner ring 25.

  Hereinafter, the steam flow in the high pressure turbine 5 will be described. The high pressure steam 102 in the nozzle box 19 is blown out and flows through the high pressure first stage moving blades 21 and then flows into the high pressure two stage stationary blades 24. Several teeth are provided in the part facing the axial rotor 11 of the high-pressure two-stage stationary blade inner ring 25, and although it has a sealing function, it is not illustrated here. In FIG. 14, the teeth are not shown in the same manner for all the vane inner rings.

  During the start-up operation (start-up time) before the above-described steam turbine shifts to the normal operation, the amount of inflowing steam is gradually increased, but at that time, the shaft rotor 11 is heated by the flowing steam. First, the temperature in the vicinity of the surface of the shaft rotor 11 rises, and the temperature in the vicinity of the center is heated by heat conduction from the vicinity of the surface and the temperature rises, so the temperature rise in the vicinity of the center is slower.

  The axial rotor 11 generates thermal stresses of compression and tension near the surface and near the center, respectively. The rotor surface thermal stress may be approximated to be proportional to the difference between the rotor surface temperature and the rotor volume average temperature, but the absolute value of the rotor surface thermal stress is a stress value related to the life determined by the rotor material May be higher than the value. At the start of the turbine, the absolute value of the rotor surface thermal stress once becomes higher than the predetermined stress value, and then the behavior which becomes lower than the predetermined stress value is indicated one or more times. There is a possibility. The same applies to the absolute value of the rotor center thermal stress, which may exceed the predetermined stress value one or more times when the turbine is started. As the total number of times when the absolute value of each of the rotor surface thermal stress and the rotor central thermal stress exceeds a predetermined stress value increases, the strength of the rotor material can not be ensured, that is, the remaining life of the rotor becomes short.

  Therefore, at the time of starting the steam turbine, the increase of the amount of inflowing steam is temporarily stopped for a certain time while the amount of inflowing steam is gradually increased to increase the turbine rotational speed from zero. During this time, the temperature rise near the rotor center continues, but the temperature drops near the surface because the amount of heat of outflow is larger than the amount of heat inflow. Then, the temperature difference between the vicinity of the surface and the vicinity of the center becomes smaller and the difference between the rotor surface temperature and the rotor volume average temperature also becomes smaller, the absolute value of the rotor surface thermal stress generated decreases, and the absolute value of the rotor central thermal stress generated The same goes for the same. When the absolute value of each of the rotor surface thermal stress and the rotor central thermal stress decreases without exceeding the predetermined stress value, the increase of the amount of inflowing steam is resumed to increase the turbine rotational speed.

  As the next step, after the steam turbine is connected to the generator, the amount of incoming steam is gradually increased to increase the turbine load from zero. Also at this time, the temperature in the vicinity of the surface of the shaft rotor 11 rises first, and the temperature in the vicinity of the center is heated by heat conduction from the vicinity of the surface and the temperature rises. Here, the increase of the amount of inflowing steam is temporarily stopped for a fixed time. During this time, the temperature in the vicinity of the rotor center continues but the temperature in the vicinity of the rotor surface decreases, so the absolute value of the rotor surface thermal stress decreases and the absolute value of the rotor central thermal stress decreases as well as the rotational speed increases. When the absolute value of each of the rotor surface thermal stress and the rotor central thermal stress decreases without exceeding the predetermined stress value, the increase of the amount of inflowing steam is resumed to increase the turbine load.

  In the steam turbine shown in FIG. 13 and FIG. 14, since the place having the highest temperature as the rotor surface temperature is immediately after the high pressure first stage moving blade 21 of the high pressure turbine 5, the place having the largest thermal stress is present.

  In addition, when steam is introduced into the steam turbine at startup of the steam turbine, the temperature of the rotating portion (such as the shaft rotor 11) having a small heat capacity rises faster than the stationary portion (such as the high pressure inner casing 13) having a large heat capacity. The amount of thermal elongation of is larger than the amount of thermal elongation of the stationary part. If the thermal expansion difference between the stationary portion and the rotating portion is large, the possibility that the stationary portion and the rotating portion come into contact increases. Therefore, while the increase of the amount of inflowing steam is stopped for a certain period of time, the temperature increase of the stationary portion is advanced to suppress the thermal elongation difference and to prevent the contact.

  By the way, in recent years, there is a demand to start up the stopped steam turbine rapidly, that is, to shorten the start-up time of the steam turbine, in order to cope with the power generation fluctuation in the whole area. For example, with the spread of solar power generation in recent years, cases where the amount of power generation in the entire region greatly fluctuates are increasing, and the need for coping with the fluctuations in amount of power generation is increasing.

Japanese Examined Patent Publication 7-122403 Patent 5634869 JP-A-59-134307 JP, 2014-163652, A JP, 2005-90771, A

  An embodiment of the present invention has an object of providing a steam turbine plant capable of shortening the startup time of the steam turbine and a method of operating the same.

  According to one embodiment, a steam turbine plant comprises a boiler for generating steam from water. The plant further comprises a first steam turbine generated in the boiler and rotationally driven by the reheated or unheated steam in the reheater. The plant may further generate a first steam generated in the boiler and heated or unheated in the reheater, a second steam having a temperature lower than the first steam, and a temperature higher than the first steam. A separation mechanism is provided to separate into the third steam, supply the second steam to the vicinity of the surface of the shaft rotor in the first steam turbine, and cool the shaft rotor with the second steam.

It is a schematic diagram which shows the structure of the steam turbine plant of 1st Embodiment. It is a schematic diagram which shows the structure of the steam turbine plant of 2nd Embodiment. It is a schematic diagram which shows the structure of the steam turbine plant of 5th Embodiment. It is a schematic diagram which shows the structure of the steam turbine plant of 6th Embodiment. It is a schematic diagram which shows the structure of the steam turbine plant of 7th Embodiment. It is a sectional view showing the structure of the steam turbine of a 1st embodiment. It is sectional drawing which shows the structure of the steam turbine of 2nd Embodiment. It is sectional drawing which shows the structure of the steam turbine of 3rd Embodiment. It is sectional drawing which shows the structure of the steam turbine of 4th Embodiment. It is sectional drawing which shows the structure of the steam turbine of 5th Embodiment. It is a sectional view showing an example of composition of the conventional steam turbine plant. It is sectional drawing which shows another structural example of the conventional steam turbine plant. It is sectional drawing which shows the structure of the conventional steam turbine. It is an expanded sectional view showing the structure of the conventional steam turbine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First Embodiment
FIG. 1 is a schematic view showing a configuration of a steam turbine plant of the first embodiment. FIG. 6 is a cross-sectional view showing the structure of the steam turbine of the first embodiment. The same reference numerals are given to the same parts as the parts shown in the previous figures, and the explanation will be omitted.

  The steam turbine plant of FIG. 1 constitutes a reheat cycle, and comprises, in addition to the components shown in FIG. 12, a vortex tube 31, a flow control valve 32, a main steam valve 33 and a bypass steam valve 34. doing. The steam turbine of FIG. 6 is a high pressure turbine 5 and includes a low temperature pipe 35 in addition to the components shown in FIGS. 13 and 14. The high pressure turbine 5 and the intermediate pressure turbine 6 according to the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31 and the cold tube 35 of the present embodiment are examples of the separation mechanism.

  In the present embodiment, the high-pressure steam 102 is branched into a first branch steam 201 which is a branch and a second branch steam 202 which is a main stream. The first branched steam 201 flows into the vortex tube 31 via the flow rate control valve 32. The flow control valve 32 is opened when using the vortex tube 31 and used for adjusting the flow rate of the first branched vapor 201, and is closed when the vortex tube 31 is not used.

  The vortex tube 31 is a widely used technology mainly for cooling applications, and for example, an atmosphere of 21 ° C. can be introduced to be separated into a gas of −47 ° C. and a gas of 35 ° C. The vortex tube 31 of the present embodiment has a function of separating the first branched steam 201 into low temperature steam 203 having a temperature lower than that of the first branched steam 201 and high temperature steam 204 having a temperature higher than that of the first branched steam 201. . The first branched steam 201, the low temperature steam 203, and the high temperature steam 204 are examples of the first steam, the second steam, and the third steam, respectively. The temperature of the first branched steam 201 is referred to as a first temperature, the temperature of the low temperature steam 203 as a second temperature, and the temperature of the high temperature steam 204 as a third temperature. The vortex tube 31 can produce low temperature steam 203 as high temperature steam 204 without using energy consuming heaters or coolers.

  The vortex tube 31 has an inlet common to the two tubes, a first outlet provided to one tube, and a second outlet provided to the other tube. The first branched steam 201 flows into the vortex tube 31 from this inlet, and the low temperature steam 203 and the high temperature steam 204 are discharged from the first outlet and the second outlet, respectively.

  The low temperature steam 203 flows into a low temperature pipe 35 (FIG. 6) provided in the high pressure turbine 5. The low temperature pipe 35 is disposed in a hole provided in the stator (the vane 24 and the vane inner ring 25 etc.) of the high pressure turbine 5, and the hole is from the surface of the high pressure turbine 5 to near the surface of the axial rotor 11. It has reached the point. In the vicinity of the outlet of the low temperature tube 35, a seal is appropriately provided near the outlet of the low temperature tube 35 so that the steam in the high pressure turbine 5 and the low temperature steam 203 do not flow between the low temperature tube 35 and the high pressure inner casing 13. Is desirable. The low temperature steam 203 flows out from the low temperature tube 35 near the surface of the shaft rotor 11.

  On the other hand, the flow path of the second branched steam 202 is branched into a flow path for transferring the main steam 206 and a flow path for transferring the bypass steam 207. A main steam valve 33 is provided in the former flow path, and a bypass valve 34 is provided in the latter flow path. The main steam 206 flows into the high pressure turbine 5, and the bypass steam 207 bypasses the high pressure turbine 5. Normally, the main steam valve 33 is fully opened and the bypass valve 34 is fully closed, but before starting the high pressure turbine 5, the main steam valve 33 is closed and the bypass valve 34 is opened.

  The main steam 206 flows into the high pressure turbine 5 and flows in the axial direction, and the low temperature steam 203 merges with the main steam 206 in the high pressure turbine 5. The pressure of the main steam 206 is reduced in the high pressure turbine 5 due to passage of a moving blade or the like. On the other hand, the pressure of the low temperature steam 203 is reduced due to the pressure drop of the vortex tube 31. In this embodiment, the vortex tube 31 is used such that the pressure of the low temperature steam 203 at the outlet of the cold tube 35 is higher than the pressure of the main steam 206 at the outlet at least when the flow control valve 32 is fully open.

  In FIG. 1, the high temperature steam 204 merges with the high pressure turbine exhaust 104, and the steam after merging is the first merged steam 205. However, the hot steam 204 may merge with the steam in the steam turbine plant elsewhere. For example, the high temperature steam 204 may flow into the outlet steam of the reheater 8, and the combined steam may be used as the medium pressure steam 105.

  Further, in FIG. 1, the bypass steam 207 joins the first combined steam 205, and the steam after the joining is the second combined steam 208. As described above, the high pressure turbine exhaust gas 104 of the present embodiment becomes a part of the first combined steam 205 and further becomes a part of the second combined steam 208 and flows into the reheater 8. The second combined steam 208 is heated by the reheater 8 and becomes the medium pressure steam 105.

  The low temperature steam 203 is supplied near the surface of the shaft rotor 11, and the surface of the shaft rotor 11 is cooled by the low temperature steam 203. As shown in FIG. 6, when the low temperature steam 203 is sprayed to the shaft rotor 11, the cooling effect of the shaft rotor 11 is increased. Since the shaft rotor 11 is rotating, only a part in the circumferential direction is cooled, and all the circuit is cooled uniformly, so that the rotation shaft of the shaft rotor 11 does not deform or remains axisymmetric. A plurality of low temperature tubes 35 may be provided.

  In FIG. 6, since the exit of the low temperature pipe 35 is located immediately after the high pressure first stage moving blade 21 of the high pressure turbine 5, the portion of the shaft rotor 11 where the thermal stress is maximum is cooled. Therefore, the inflow amount increase stop time at the time of start can be shortened by this cooling, and the start time of the plant can be shortened. The above-mentioned cooling place is an example of the first place. In the present embodiment, the flow control valve 32 is opened when the surface of the shaft rotor 11 is cooled, such as when the high pressure turbine 5 is started. On the other hand, when the surface of the shaft rotor 11 is not cooled, the flow control valve 32 is closed.

  In the present embodiment, steam may be extracted from the inside of the boiler 1 and flowed into the vortex tube 31. Further, the low temperature pipe 35 may be provided to the steam turbine 2 of FIG. 11 instead of being provided to the high pressure turbine 5. The same applies to the second to eighth embodiments described later.

  In FIG. 1, the flow path of the second branched steam 202 is branched into a flow path for transferring the main steam 206 and a flow path for transferring the bypass steam 207. This configuration may be applied to FIGS. 2 to 5 described later.

Second Embodiment
FIG. 2 is a schematic view showing the configuration of the steam turbine plant of the second embodiment. FIG. 7 is a cross-sectional view showing the structure of the steam turbine of the second embodiment. The same reference numerals are given to the same parts as the parts shown in the above-mentioned figures, and the explanation will be omitted.

  The steam turbine plant of FIG. 2 constitutes a reheat cycle in the same manner as the steam turbine plant of FIG. The steam turbine of FIG. 7 is a high pressure turbine 5 and comprises a high temperature pipe 36 in addition to the components shown in FIG. The high pressure turbine 5 and the intermediate pressure turbine 6 according to the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31, the low temperature tube 35, and the high temperature tube 36 according to the present embodiment are examples of the separation mechanism.

  In the first embodiment, the high temperature steam 204 is made to flow into the high pressure turbine exhaust 104, but the steam for driving the impeller of the high pressure turbine 5 is reduced in flow rate. I would like to introduce 204 and increase the steam that drives the impeller. In the second embodiment, the high temperature steam 204 is made to flow in the vicinity of the flow passage side wall surface of a stator (stationary component) that constitutes a part of the flow passage of the steam that drives the impeller. The stationary component is the high pressure inner casing 13 in FIG. 6, but depending on the component configuration, the stationary blade outer ring 12 or the stationary blade inner ring may be used.

  The high temperature steam 204 flows into a high temperature pipe 36 provided in the high pressure turbine 5. From the discharge flow path of the high temperature steam 204 from the vortex tube 31 to the surface of the shaft rotor 11, a hole is provided in each component such as the high pressure inner casing 13 and the outer casing 14 and a high temperature tube 36 is installed. It is desirable that a seal be appropriately applied near the high temperature steam 204 so that the steam or the high temperature steam 204 at the outflow point (outlet of the high temperature tube 36) does not flow between the high temperature tube 36 and the high pressure inner casing 13.

  The high temperature steam 204 flows out near the inner surface of the high pressure inner casing 13 and merges with the second branch steam 202 flowing into the high pressure turbine 5. The pressure of the second branched steam 202 decreases in the high pressure turbine 5 due to passage of a moving blade or the like. On the other hand, the pressure of the high temperature steam 204 decreases due to the pressure loss of the vortex tube 31. In this embodiment, the vortex tube 31 is used such that the pressure of the high temperature steam 204 at the outlet of the high temperature tube 36 is higher than the pressure of the second branched steam 202 at the outlet, at least when the flow control valve 32 is fully open.

  The inflow of the low temperature steam 203 cools the surface of the shaft rotor 11, and the inflow of the high temperature steam 204 heats the inner surface of the high pressure inner casing 13. That is, since the rotating part is cooled and the stationary part is heated, the thermal expansion difference between the stationary part and the rotating part becomes smaller, and the possibility of contact between the stationary part and the rotating part becomes lower.

  Therefore, although the thermal expansion difference was conventionally suppressed by advancing the temperature rise of the stationary portion while stopping the increase of the inflow vapor amount for a certain time, this time can be shortened according to the present embodiment. According to this embodiment, it is possible to shorten the increase stop time of the inflowing steam amount at the time of startup of the high pressure turbine 5, and to shorten the startup time of the plant. The second embodiment also has the effect of the first embodiment, and strengthens the effect of the first embodiment. Moreover, the flow rate of the steam which drives an impeller is increasing from 1st Embodiment.

  If only one high temperature pipe 36 is used, heating of the stationary portion is uneven in the circumferential direction, and the temperature rise is likely to be uneven, so it is desirable to provide a plurality of high temperature pipes 36. In the present embodiment, the flow control valve 32 is opened when the surface of the shaft rotor 11 is cooled, such as at start-up, and the flow control valve 32 is closed when the surface of the shaft rotor 11 is not cooled. The supply and the stop of the supply of the high temperature steam 204 are also controlled by the opening and closing of the flow control valve 32.

  The low temperature pipe 35 and the high temperature pipe 36 may be provided in the steam turbine 2 of FIG. 11 instead of being provided in the high pressure turbine 5. This is the same as in the third and fourth embodiments described later.

Third Embodiment
FIG. 8 is a cross-sectional view showing the structure of the steam turbine of the third embodiment. The steam turbine of FIG. 8 is installed in the steam turbine plant of FIG. The same reference numerals are given to the same parts as the parts shown in the above-mentioned figures, and the explanation will be omitted, and only differences from the prior art and the first and second embodiments will be explained.

  The steam turbine of FIG. 8 is a high pressure turbine 5 similar to the steam turbine of FIG. 7. The high pressure turbine 5 and the intermediate pressure turbine 6 according to the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31, the low temperature tube 35, and the high temperature tube 36 according to the present embodiment are examples of the separation mechanism.

  In the second embodiment, the high temperature steam 204 is made to flow into the vicinity of the flow passage side wall surface of the stationary component that constitutes a part of the flow passage of the steam that drives the impeller. However, since this part is heated by the flowing steam, the temperature rise of the stationary part is faster if the unheated area is heated using the high temperature steam 204. Therefore, the high temperature steam 204 is made to flow into the region between the high pressure inner casing 13 and the outer casing 14 (intermediate region R).

  The high pressure inner casing 13 of FIG. 13 is shaped such that the high pressure inner casing 13 and the outer casing 14 are fitted. However, since this is not divided in the axial vertical plane around the circumference in the axial direction, the inter-region R may be any region sandwiched between the high-pressure inner casing 13 and the outer casing 14. Moreover, although the high temperature steam 204 is made to flow out near the outer surface of the high voltage | pressure internal casing 13 in FIG. When the high temperature steam 204 flows into the space R, the temperature of the steam in the space R thereby rises, and the high-pressure inner casing 13 and the outer casing 14 are heated. In addition, since the inter-region R communicates with the high pressure exhaust chamber 15, it is not a dead end, and the steam in the inter-region R has the same pressure as the high-pressure turbine final stage outlet steam.

  The high temperature steam 204 flows into a high temperature pipe 36 provided in the high pressure turbine 5. A hole is provided in the outer casing 14 and a high temperature pipe 36 is installed from the discharge flow path of the high temperature steam 204 from the vortex tube 31 to the vicinity of the outer surface of the high pressure inner casing 13. It is desirable that a seal be appropriately applied near the high temperature steam 204 so that the steam at the outflow point of the high temperature steam 204 and the high temperature steam 204 do not flow between the high temperature tube 36 and the outer casing 14.

  The high temperature steam 204 flows out into the interregion R, and merges with the vapor in the interregion R. Since the pressure of the steam in the intermediate region R is sufficiently low, the pressure of the high temperature steam 204 is higher than the pressure of the second branched steam 202 at the outflow point even if the vortex tube 31 has some pressure drop.

  The inflow of the low temperature steam 203 cools the surface of the shaft rotor 11, and the inflow of the high temperature steam 204 heats the outer surface of the high pressure inner casing 13. That is, since the rotating part is cooled and the stationary part is heated, the thermal expansion difference between the stationary part and the rotating part becomes smaller, and the possibility of contact between the stationary part and the rotating part becomes lower.

  Therefore, although the thermal expansion difference was conventionally suppressed by advancing the temperature rise of the stationary portion while stopping the increase of the inflow vapor amount for a certain time, this time can be shortened according to the present embodiment. According to this embodiment, it is possible to shorten the increase stop time of the inflowing steam amount at the time of startup of the high pressure turbine 5, and to shorten the startup time of the plant. According to the present embodiment, more efficient temperature rise can be realized than the second embodiment in which the inner surface of the high pressure inner casing 13 is heated. The third embodiment also has the effect of the first embodiment, and strengthens the effect of the first embodiment.

  If only one high temperature pipe 36 is used, the heating of the stationary portion is uneven in the circumferential direction, and the temperature rise is likely to be uneven, so it is desirable to provide a plurality of high temperature pipes 36. In the present embodiment, the flow control valve 32 is opened when the surface of the shaft rotor 11 is cooled, such as at start-up, and the flow control valve 32 is closed when the surface of the shaft rotor 11 is not cooled. The supply and the stop of the supply of the high temperature steam 204 are also controlled by the opening and closing of the flow control valve 32.

Fourth Embodiment
FIG. 9 is a cross-sectional view showing the structure of the steam turbine of the fourth embodiment. The steam turbine of FIG. 9 is installed in the steam turbine plant of FIG. The same reference numerals are given to the same parts as the parts shown in the above-mentioned figures, and the description will be omitted, and only differences from the prior art and the first to third embodiments will be described.

  The steam turbine of FIG. 9 is a high pressure turbine 5 similar to the steam turbine of FIG. The high pressure turbine 5 and the intermediate pressure turbine 6 according to the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31, the low temperature tube 35, and the high temperature tube 36 according to the present embodiment are examples of the separation mechanism.

  In the third embodiment, the high temperature steam 204 is caused to flow into the vicinity of the outer surface of the high pressure inner casing 13. In the fourth embodiment, the high temperature steam 204 is caused to flow into the vicinity of the inner surface of the outer casing 14 to heat the outer casing 14. As shown in FIG. 8, when the high temperature steam 204 is blown to the inner surface of the outer casing 14, its heating effect is enhanced. In the case of a turbine in which the volume of the outer casing 14 is sufficiently large, the temperature rise of the stationary portion is difficult to advance because the heat capacity of the outer casing 14 is sufficiently large, but the temperature rise proceeds by this heating. Therefore, the thermal expansion difference between the stationary portion and the rotating portion is further reduced, and the same effect as that of the third embodiment is sufficiently obtained.

  If only one high temperature pipe 36 is used, heating of the stationary portion is uneven in the circumferential direction, and the temperature rise is likely to be uneven, so it is desirable to provide a plurality of high temperature pipes 36. Also, in order to make the high temperature steam 204 more easily sprayed by the inner surface of the outer casing 14, for example, the shape of the high temperature tube 36 is U-shaped near the outlet or keeps the high temperature steam 204 in front of the outlet of the high temperature tube 36. You may set up a baffle for this purpose.

Fifth Embodiment
FIG. 3 is a schematic view showing the configuration of the steam turbine plant of the fifth embodiment. FIG. 10 is a cross-sectional view showing the structure of the steam turbine of the fifth embodiment. The same parts as the parts shown in the above-mentioned drawings are given the same reference numerals, and the description thereof will be omitted. Only differences from the prior art and the first to fourth embodiments will be described.

  The steam turbine plant of FIG. 3 constitutes a reheat cycle in the same manner as the steam turbine plant of FIGS. 1 and 2. The steam turbine of FIG. 10 is an intermediate pressure turbine 6 and includes an intermediate pressure inner casing 37 in addition to the components shown in FIGS. 13, 14 and 5 to 9. The medium pressure turbine 6 and the high pressure turbine 5 of the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31 and the cold tube 35 of the present embodiment are examples of the separation mechanism.

  The low temperature steam 203 flows into a low temperature pipe 35 provided in the intermediate pressure turbine 6. From the discharge flow path of the low temperature steam 203 from the vortex tube 31 to the surface of the shaft rotor 11, a hole is provided in each component such as a stationary blade and a low temperature tube 35 is installed. It is desirable that a seal be appropriately provided near this point so that the steam at the outflow point of the cold vapor 203 and the low temperature steam 203 do not flow between the low temperature tube 35 and the medium pressure inner casing 37 and the outer casing 14.

  The low temperature steam 203 flows out near the surface of the shaft rotor 11. And although it joins with the medium pressure steam 105, the pressure of the medium pressure steam 105 is sufficiently lower than that of the high pressure steam 102, so even if the vortex tube 31 has some pressure loss, the pressure of the low temperature steam 203 is It is higher than the pressure of the medium pressure steam 105. However, since it is desirable that the temperature of the low-temperature steam 203 be lower than the condensation point so that no water droplets are generated, the vortex tube 31 which does not cause a drastic temperature decrease is used. The remaining second branched steam 202 obtained by branching the first branched steam 201 from the high pressure steam 102 flows into the high pressure turbine 5.

  The high temperature steam 204 flows into the inside of the intermediate pressure turbine 6 in FIG. 3, but is not shown in FIG. 10 for convenience of illustration. The outflow point of the high temperature steam 204 may be in the vicinity of the flow passage side wall surface of a stationary part which constitutes a part of the flow passage for driving the impeller in the same manner as in the second embodiment. Third and fourth embodiments Similarly, it may be in the region between the medium pressure inner casing 37 and the outer casing 14. Further, the outflow point of the high temperature steam 204 may be the high pressure turbine exhaust 104 as in the first embodiment different from that of FIG. 3 or the outflow steam of the reheater 8.

  The inflow of the low temperature steam 203 cools the surface of the shaft rotor 11. As shown in FIG. 10, when the low temperature steam 203 is sprayed, the cooling effect is enhanced. Since the shaft rotor 11 is rotating, only a part in the circumferential direction is not cooled but is cooled equally all around, so that the rotation shaft of the shaft rotor 11 does not deform or remains axisymmetric.

  Depending on the conditions of the Rankine cycle, the medium pressure first stage stator blade 22 to the medium pressure first stage rotor blade 23 in front of the axial position from the first stage stator blade of the high pressure turbine 5 to the front of the second stage rotor blade The axial position of the rotor may be higher or equal to the rotor surface temperature. In FIG. 10, the point is cooled. Therefore, the inflow steam volume increase stop time at the time of starting of the intermediate pressure turbine 6 can be shortened, and the starting time of the plant can be shortened. Here, the first stage vane front of the high pressure turbine 5 means the upstream side of the first stage vane, and the two stage vane front of the high pressure turbine 5 means the upstream side of the two stage vane. The same applies to the medium pressure first stage stationary blades 22 of the medium pressure turbine 6 and the medium pressure first stage rotor blades 23 before.

  In the present embodiment, the flow control valve 32 is opened when the surface of the shaft rotor 11 is cooled, such as at start-up, and the flow control valve 32 is closed when the surface of the shaft rotor 11 is not cooled. The supply and the stop of the supply of the high temperature steam 204 are also controlled by the opening and closing of the flow control valve 32.

Sixth Embodiment
FIG. 4 is a schematic view showing the configuration of the steam turbine plant of the sixth embodiment. The same reference numerals are given to the same parts as the parts shown in the above-mentioned figure, and the explanation will be omitted, and only differences from the prior art and the first to fifth embodiments will be explained.

  The steam turbine plant of FIG. 4 constitutes a reheat cycle in the same manner as the steam turbine plant of FIGS. 1 to 3. The sixth embodiment will be described with reference to FIGS. 4 and 10. The medium pressure turbine 6 and the high pressure turbine 5 of the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31 and the cold tube 35 of the present embodiment are examples of the separation mechanism.

  In the reheat cycle shown in FIG. 12, the third branch steam 211 is branched from the high pressure turbine exhaust gas 104 and flows into the vortex tube 31 through the flow rate control valve 32. The third branch steam 211 flowing into the vortex tube 31 is separated into the high temperature steam 204 and the low temperature steam 203, and the low temperature steam 203 flows into the low temperature pipe 35 provided in the intermediate pressure turbine 5. From the discharge flow path of the low temperature steam 203 from the vortex tube 31 to the surface of the shaft rotor 11, a hole is provided in each component such as the medium pressure first stage stator blade 22 and a low temperature tube 35 is installed. It is desirable that a seal be appropriately provided near this point so that the steam at the outflow point of the cold steam 203 and the low temperature steam 203 do not flow between the low temperature tube 35 and the medium pressure inner casing 11 and the outer casing 14.

  The low temperature steam 203 flows out near the surface of the shaft rotor 11. And although the low temperature steam 20 merges with the medium pressure steam 105, since the pressure of the medium pressure steam 105 is sufficiently lower than the high pressure turbine exhaust 104, even if the vortex tube 31 has some pressure loss, the low temperature steam 203 Is higher than the pressure of the medium pressure steam 105 at the outflow point. The remaining fourth branch steam 212 obtained by branching the third branch steam 211 from the high pressure turbine exhaust 104 flows into the reheater 8.

  The high temperature steam 204 flows into the inside of the intermediate pressure turbine 6 in FIG. 3, but is not shown in FIG. 10 for convenience of illustration. The outflow point of the high temperature steam 204 may be in the vicinity of the flow passage side wall surface of a stationary part which constitutes a part of the flow passage for driving the impeller in the same manner as in the second embodiment. Third and fourth embodiments Similarly, it may be in the region between the medium pressure inner casing 37 and the outer casing 14. Further, the outflow point of the high temperature steam 204 may be the fourth branched steam 212 as in the first embodiment, which is different from FIG. 3, or may be the outflow steam of the reheater 8.

  The configuration of the sixth embodiment has the same effect as the configuration of the fifth embodiment. Furthermore, as compared with the fifth embodiment, in the sixth embodiment, since the steam flowing into the vortex tube 31 is low temperature, the low temperature steam 203 also becomes lower temperature, and the cooling action becomes stronger. The same configuration as that of the first and second embodiments can be applied to the sixth embodiment.

Seventh Embodiment
FIG. 5 is a schematic view showing a configuration of a steam turbine plant of a seventh embodiment. The same parts as the parts shown in the above-mentioned drawings are given the same reference numerals, and the description thereof will be omitted. Only differences from the prior art and the first to sixth embodiments will be described.

  The steam turbine plant of FIG. 5 constitutes a reheat cycle in the same manner as the steam turbine plant of FIGS. The seventh embodiment will be described with reference to FIGS. 5 and 10. The medium pressure turbine 6 and the high pressure turbine 5 of the present embodiment are examples of first and second steam turbines, respectively. The vortex tube 31 and the cold tube 35 of the present embodiment are examples of the separation mechanism.

  In the reheating cycle shown in FIG. 12, the medium pressure steam 105 to the fifth branch steam 213 are branched and flow into the vortex tube 31 through the flow rate control valve 32. The fifth branch steam 213 flowing into the vortex tube 31 is separated into the high temperature steam 204 and the low temperature steam 203, and the low temperature steam 203 flows into the low temperature pipe 35 provided in the intermediate pressure turbine 5. From the discharge flow path of the low temperature steam 203 from the vortex tube 31 to the surface of the shaft rotor 11, a hole is provided in each component such as the medium pressure first stage stator blade 22 and a low temperature tube 35 is installed. It is desirable that a seal be appropriately provided near this point so that the steam at the outflow point of the cold steam 203 and the low temperature steam 203 do not flow between the low temperature tube 35 and the medium pressure inner casing 11 and the outer casing 14.

  The low temperature steam 203 flows out near the surface of the shaft rotor 11. The remaining sixth branch steam 214 obtained by branching the medium pressure steam 105 to the fifth branch steam 213 flows into the medium pressure turbine 6 and then merges with the low temperature steam 203. The pressure of the sixth branch steam 214 is reduced in the intermediate pressure turbine 6 due to the blade passing and the like. On the other hand, the pressure of the low temperature steam 203 is reduced due to the pressure drop of the vortex tube 31. In this embodiment, the vortex tube 31 is used such that the pressure of the low temperature steam 203 at the outlet of the cold tube 35 is higher than the pressure of the sixth branched steam 214 at the outlet, at least when the flow control valve 32 is fully open. The details of the high temperature steam 204 are the same as in the sixth embodiment.

  The configuration of the seventh embodiment has the same effect as the configuration of the fifth embodiment. The same configuration as that of the first and second embodiments can be applied to the seventh embodiment.

Eighth Embodiment
The eighth embodiment will be described with reference to FIG. In the eighth embodiment, the surface temperature of the shaft rotor 11 is measured using the technique for noncontact measurement of the surface temperature of the shaft rotor 11 in the first to seventh embodiments. Such non-contact measurement can be performed using, for example, a radiation thermometer.

  In the present embodiment, the measurement result of the surface temperature of the shaft rotor 11 is input from the radiation thermometer to a control device (not shown) that controls the operation of the steam turbine plant. The controller opens and closes the flow control valve 32 and adjusts the opening degree so that the measured value of the surface temperature of the shaft rotor 11 does not exceed a predetermined allowable temperature, and the flow rate of the steam flowing into the vortex tube 31 Control.

  According to the present embodiment, the cooling of the rotor by the low temperature steam 203 and the heating of the casing by the high temperature steam 204 can be appropriately controlled, and the start of the steam turbine can be favorably performed.

  While certain embodiments have been described above, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. The novel plants and methods described herein may be implemented in various other forms. In addition, various omissions, substitutions, and modifications can be made to the forms of the plant and the method described in the present specification without departing from the scope of the invention. The appended claims and their equivalents are intended to cover such forms and modifications as would fall within the scope and spirit of the invention.

1: Boiler, 2: Steam turbine, 3: Condenser, 4: Pump,
5: high pressure turbine, 6: medium pressure turbine, 7: low pressure turbine, 8: reheater,
11: axial rotor, 12: stator outer ring, 13: high pressure inner casing,
14: outer casing, 15: high pressure exhaust chamber, 16: medium pressure exhaust chamber,
17: main steam pipe, 18: reheat steam pipe, 19: nozzle box,
20: temperature sensor (thermocouple), 21: high pressure first stage rotor blade, 22: medium pressure first stage stator blade,
23: Medium pressure first stage rotor blade, 24: high pressure two stage stator blade, 25: two stage stator blade inner ring,
31: Vortex tube, 32: Flow control valve, 33: Main steam valve,
34: bypass steam valve, 35: low temperature pipe, 36: high temperature pipe, 37: medium pressure inner casing,
101: water, 102: high pressure steam, 103: steam turbine exhaust,
104: high pressure turbine exhaust, 105: medium pressure steam, 106: medium pressure turbine exhaust,
107: low pressure turbine exhaust, 201: first branch steam, 202: second branch steam,
203: low temperature steam, 204: high temperature steam, 205: first combined steam, 206: main steam,
207: bypass steam, 208: second combined steam, 211: third branch steam,
212: 4th branch steam, 213: 5th branch steam, 214: 6th branch steam

Claims (11)

A boiler that generates steam from water;
A first steam turbine generated in the boiler and rotated by steam heated or unheated in a reheater;
The first steam generated in the boiler and heated or not heated in the reheater is converted into a second steam having a temperature lower than the first steam and a third steam having a temperature higher than the first steam. A separation mechanism that separates and supplies the second steam near the surface of the shaft rotor in the first steam turbine to cool the shaft rotor with the second steam;
Steam turbine plant characterized by having. The reheater which heats the steam discharged from the first steam turbine;
And a second steam turbine which is generated by the boiler, flows through the first steam turbine, and is rotationally driven by the steam heated by the reheater,
The separation mechanism separates the first steam extracted from the steam flow path between the boiler and the first steam turbine into the second steam and the third steam. The steam turbine plant according to claim 1. A second steam turbine that is rotationally driven by steam generated by the boiler;
The reheater heating the steam discharged from the second steam turbine;
Further equipped,
The said 1st steam turbine generate | occur | produces in the said boiler, distribute | circulates the said 2nd steam turbine, It is rotationally driven by the steam heated by the said reheater, It is characterized by the above-mentioned. Steam turbine plant.   The separation mechanism is a steam flow passage between the boiler and the second steam turbine, a steam flow passage between the second steam turbine and the reheater, or the reheater and the first steam turbine The steam turbine plant according to claim 3, characterized in that the first steam extracted from the steam flow path between them is separated into the second steam and the third steam. The separation mechanism supplies the second steam to a first location of the shaft rotor,
The axial position of the first location is a position in front of the first stage stator blade of the first steam turbine, or a position from the front of the first stage stator blade of the first steam turbine to a second stage rotor blade. The steam turbine plant according to any one of claims 1 to 4.   The steam turbine plant according to any one of claims 1 to 5, wherein the separation mechanism supplies the third steam to the first steam turbine.   The steam turbine plant according to claim 6, wherein the separation mechanism heats a stationary portion in the first steam turbine with the third steam. The casing surrounding the rotating portion of the first steam turbine has a double configuration of an inner casing and an outer casing,
The separation mechanism is characterized in that the third vapor is supplied to a region between the inner casing and the outer casing, near an outer surface of the inner casing, or near an inner surface of the outer casing. 8. A steam turbine plant according to item 6 or 7.   The steam turbine plant according to any one of claims 1 to 8, wherein the separation mechanism comprises a vortex tube. Generate steam from water in the boiler,
Driving the first steam turbine by the steam generated in the boiler and heated or not in the reheater;
The first steam generated in the boiler and heated or not heated in the reheater is separated by a separation mechanism with a second steam having a temperature lower than the first temperature, and a first steam having a temperature higher than the first temperature. Three steams are separated, the second steam is supplied from the separation mechanism to the shaft rotor in the first steam turbine, and the shaft rotor is cooled by the second steam.
What is claimed is: 1. A method of operating a steam turbine plant comprising:   The steam according to claim 10, wherein the surface temperature of the shaft rotor is measured, and the flow rate of the first steam is controlled so that the measured temperature of the surface temperature does not exceed a predetermined allowable temperature. How to operate a turbine plant.

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