JP2016075189A - Steam chest of geothermal turbine, geothermal turbine with steam chest and geothermal turbine steam supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce occurrence of repeated load for a row of rotor blades of an initial stage turbine by a method in which steam can be supplied uniformly from both initial stage nozzle ports at a main steam chest and a sub-steam chest along a peripheral direction of the initial stage turbine when the sub steam chest is operated.SOLUTION: A steam chest 21 of a geothermal turbine 1 comprises an annular steam chest casing 4 enclosing a turbine rotor 3 and formed with first stage nozzle ports 8a along its peripheral direction; partition walls 11, 12 for defining an inside part of the steam chest casing 4 into a main steam chest 14 and a sub-steam chest 15 having a smaller volume than that of the main steam chest 14; a main steam pipe 18 for supplying geothermal steam to the steam chest casing 14; a sub-steam pipe 19 connecting the main steam chest 14 with the sub-steam chest 15 and distributing a part of the geothermal steam supplied to the main steam chest 14 to the sub-steam chest 15; and on-off valve 20 arranged at the sub-steam pipe 19. The partition walls 11, 12 can change their fixing positions at a peripheral direction of the steam chest casing 4.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steam chamber of a geothermal turbine, a geothermal turbine including the same, and a steam supply method of the geothermal turbine.

In geothermal turbines, impurities such as scale contained in geothermal steam collected from geothermal wells are likely to adhere to and accumulate on the first stage nozzle port without being removed by a separator etc. If left untreated, the opening area of the first stage nozzle port However, there is a problem that the turbine output and the turbine efficiency are significantly reduced.
In order to compensate for this difficulty, as disclosed in Patent Documents 1 and 2, the inside of the annular steam chamber provided with the first stage nozzle port is partitioned by a plurality of partition walls, one main steam chamber having a large volume, There is known a nozzle-regulated geothermal turbine in which one or a plurality of sub steam chambers having a small volume are defined and the sub steam chambers can be individually opened and closed.

  In this nozzle-controlled geothermal turbine, the rated output can be obtained only by the amount of steam supplied from the main steam chamber to the turbine before the impurities accumulate at the first stage nozzle port. When the pressure decreases, the sub steam chambers are sequentially opened to compensate for the decrease in the amount of steam supplied to the turbine to recover the decrease in turbine output. Thereby, it is possible to extend the time of maintenance performed by opening and disassembling the turbine, and the operating rate of the geothermal turbine plant can be increased.

JP-A-6-221106 JP2013-204469A

In the nozzle-regulated geothermal turbine disclosed in Patent Documents 1 and 2, the sub-steam pipe that supplies steam to the sub-steam chamber is branched from the main steam pipe that supplies steam to the main steam chamber. Steam of the same pressure is supplied to the steam chamber and the sub-steam chamber.
As described above, when the output of the turbine is reduced and the sub steam chamber is operated, the opening area of the first stage nozzle port of the main steam chamber where impurities are accumulated is narrowed, and the sub steam chamber where impurities are not accumulated is narrowed. The opening area of the first stage nozzle opening is large.
Since the same-pressure steam is supplied to the first-stage nozzle ports of the main steam chamber and the sub-steam chamber having different opening areas in this way, the amount (pressure) of steam flowing into the first-stage turbine is limited to the position of the sub-steam chamber. growing. In other words, there is a concern that uniform steam supply cannot be performed along the circumferential direction of the first stage turbine, and a repeated load that causes metal fatigue is applied to the rotor blade row of the first stage turbine.

  In addition, since the sub-steam piping for supplying steam to the sub-steam chamber is connected to the steam chamber casing from a position away from the steam chamber casing, the sub-steam piping is arranged separately from the installation work of the steam chamber casing. It was also necessary to perform construction work, which increased the construction period and costs.

  Furthermore, drain water in which steam is condensed may accumulate in the sub steam pipe, and it is necessary to drain the drain water before opening the sub steam chamber.

The present invention has been made in view of such circumstances, and when the sub-steam chamber is in operation, the first-stage nozzle ports of both the main steam chamber and the sub-steam chamber are uniformly distributed along the circumferential direction of the first-stage turbine. An object of the present invention is to provide a steam chamber of a geothermal turbine capable of supplying steam and reducing the occurrence of repetitive loads on the rotor blade row of the first stage turbine, a geothermal turbine provided with the same, and a steam supply method of the geothermal turbine And
A further object of the present invention is to facilitate installation work and piping work, to avoid a decrease in output due to installation of a sub-steam chamber, and to simplify the work of draining drain water.

  In order to solve the above problems, the present invention employs the following means.

  That is, the steam chamber of the geothermal turbine according to the present invention has an annular shape surrounding the turbine rotor, and the steam chamber casing in which the first stage nozzle port is formed along the circumferential direction of the steam chamber and the interior of the steam chamber casing are connected to the main steam. A partition that is divided into a chamber, a sub-steam chamber having a smaller volume than the main steam chamber, a main steam pipe that supplies geothermal steam to the main steam chamber, and the main steam chamber and the sub-steam chamber are connected to each other. And a sub-steam pipe for distributing a part of the geothermal steam supplied to the main steam chamber to the sub-steam chamber, and a valve provided in the sub-steam pipe.

  In the above structure, part of the geothermal steam supplied from the main steam pipe to the main steam chamber is distributed to the sub steam chamber via the sub steam pipe. For this reason, the amount (pressure) of the geothermal steam supplied to the sub steam chamber is smaller than the geothermal steam supplied to the main steam chamber due to the pressure loss in the sub steam pipe.

  When the turbine output is lowered and the sub steam chamber is operated, that is, when the on-off valve provided in the sub steam pipe is opened, the opening area of the first stage nozzle port of the main steam chamber where impurities are accumulated is narrowed. The opening area of the first stage nozzle port of the sub vapor chamber where no impurities are deposited remains large.

  Therefore, during operation of the sub steam chamber, the difference between the amount of steam ejected from the narrow first stage nozzle port of the main steam chamber and the amount of steam ejected from the wide first stage nozzle port of the sub steam chamber is reduced, and Steam can be uniformly supplied from both first stage nozzle ports of the steam chamber along the circumferential direction of the first stage turbine, and the occurrence of repeated loads on the rotor blade rows of the first stage turbine can be reduced.

  Moreover, since the sub-steam pipe for supplying steam to the sub-steam chamber extends from the steam chamber casing and is connected to the steam chamber casing again, the steam chamber casing and the sub-steam pipe are integrated (modularized). This can facilitate the transportation and installation work to the installation site and the piping work of the sub-steam pipe.

  In the above configuration, the partition wall has an axial center in a rotational direction and an opposite direction of the turbine rotor with a vertical center line passing through the axial center line of the turbine rotor as a base point when viewed in the axial direction of the turbine rotor. The steam chamber casing is fixed at a predetermined position in the circumferential direction so as to form a sandwiching angle centered on a line, and the partition wall is fixed at a fixed position so that the sandwiching angle changes. It may be changeable in the circumferential direction.

  According to this configuration, the volume ratio between the main steam chamber and the sub steam chamber can be appropriately set and changed according to the specifications of the geothermal turbine. Further, the position of the partition wall can be adjusted in accordance with the positions of the plurality of first stage nozzle ports formed in the steam chamber casing, thereby avoiding a decrease in output due to the installation of the sub steam chamber.

  In the above configuration, the partition may be bent or curved so as to follow a blade shape of a moving blade row of a first stage turbine provided in the turbine rotor.

  According to this configuration, the shape of the partition wall can be aligned with the rotor blade shape of the first stage turbine and the arrangement thereof, and the flow of steam ejected from the nozzle of the first stage can be aligned with the shape and arrangement of the blades of the first stage turbine. it can. That is, the flow of the steam injected from the first stage nozzle port to the first stage turbine side is not hindered by the partition walls, thereby avoiding a decrease in turbine output due to the installation of the sub steam chamber (partition wall).

  In the above configuration, the sub steam chamber is provided in the vicinity of the uppermost vertical portion of the steam chamber casing, and the sub steam pipe extends from the main steam chamber from a position vertically higher than the axis of the turbine rotor. It is preferable that the sub steam chamber is connected to the sub steam chamber from above, and the valve is provided in the vicinity of the uppermost vertical portion of the sub steam pipe.

  According to this configuration, since the drain water in which the steam is condensed does not accumulate in the sub steam pipe, the operation of draining the drain water before opening the sub steam chamber can be simplified.

Said structure WHEREIN: It is preferable that the said valve is a flow regulating valve.
As a result, when operating the sub-steam chamber as the rated output of the geothermal turbine decreases, the geothermal turbine can be operated by gradually opening the flow rate adjustment valve provided in the sub-steam pipe. Since the steam can be introduced into the sub steam chamber while continuing, it is not necessary to stop the operation of the geothermal turbine, and the operability can be improved. Further, the amount of steam flowing into the sub steam chamber from the sub steam pipe can be appropriately adjusted according to the operation state of the geothermal turbine.

Moreover, the geothermal turbine according to the present invention is characterized by including the steam chamber of any one of the above aspects.
As a result, during operation of the sub-steam chamber, steam can be uniformly supplied from the first-stage nozzle ports of both the main steam chamber and the sub-steam chamber along the circumferential direction of the first-stage turbine, and repeated to the rotor blade row of the first-stage turbine. Generation of load can be reduced, installation work and piping work can be facilitated, output reduction due to the installation of the sub-steam chamber can be avoided, and the operation of draining drain water can be simplified.

  Further, the geothermal turbine steam supply method according to the present invention is an annular shape surrounding the turbine rotor, and the interior of the steam chamber casing provided with the first stage nozzle port along the circumferential direction is connected to the main steam chamber and the main steam chamber. A sub-steam chamber having a smaller volume than the steam chamber is partitioned, and a part of the geothermal steam supplied to the main steam chamber is distributed to the sub-steam chamber.

According to this steam supply method, since a part of the steam supplied to the main steam chamber is distributed to the sub steam chamber, the amount (pressure) of steam supplied to the sub steam chamber due to the pressure loss in the sub steam piping. Becomes smaller than the steam supplied to the main steam chamber.
For this reason, when the output of the turbine is reduced and the sub-steam chamber is operated, the amount of steam ejected from the first stage nozzle port of the main steam chamber where impurities are deposited and the opening area is narrowed, and impurities are not deposited. The difference between the amount of steam ejected from the first stage nozzle port of the sub-steam chamber with a large opening area is reduced, and the steam is supplied uniformly along the circumferential direction of the first stage turbine to the moving blade row of the first stage turbine. The occurrence of repeated load can be reduced.

  In the steam supply method of the geothermal turbine, when the geothermal turbine starts to operate, the geothermal steam is supplied from only the main steam chamber to the turbine rotor side, and when a predetermined operation time has elapsed from the start of operation, or It is preferable that a part of the geothermal steam supplied to the main steam chamber is distributed to the sub-steam chamber when the output of the geothermal turbine is reduced by a predetermined amount.

  According to this steam supply method, when impurities such as scale are deposited at the first stage nozzle port of the main steam chamber and the opening area is narrowed and the turbine output is reduced, the sub steam chamber is operated, whereby the main steam chamber is operated. The total opening area of the first-stage nozzle port of the sub-steam chamber and the sub-steam chamber can be approximated to the opening area of the first-stage nozzle port in the main steam chamber before the output is reduced, and the output reduction can be recovered. As a result, the period from the start of operation of the geothermal turbine until it must be opened and disassembled for maintenance can be extended, and the operating rate of the geothermal turbine plant can be increased.

  As described above, according to the steam chamber of the geothermal turbine according to the present invention, the geothermal turbine including the same, and the steam supply method of the geothermal turbine, both the main steam chamber and the sub steam chamber are operated during the operation of the sub steam chamber. Steam can be supplied uniformly from the first stage nozzle port along the circumferential direction of the first stage turbine, and the occurrence of repeated loads on the rotor blade row of the first stage turbine can be reduced. In addition, the installation work and the piping work can be facilitated, the output reduction due to the installation of the sub steam chamber can be avoided, and the work of draining the drain water can be simplified.

It is a longitudinal cross-sectional view which shows an example of the geothermal turbine which can apply the steam chamber of the geothermal turbine which concerns on this invention. It is a longitudinal cross-sectional view of the steam chamber casing which shows 1st Embodiment of this invention by the longitudinal cross-section in alignment with the II-II line of FIG. It is a graph which shows the change of the operation time of a geothermal turbine when operating a sub steam room, and an output. It is a longitudinal cross-sectional view of the steam chamber casing which shows 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the steam chamber casing which shows 3rd Embodiment of this invention.

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

[First Embodiment]
FIG. 1 is a longitudinal sectional view showing an example of a geothermal turbine to which a steam chamber according to the present invention can be applied, and FIG. 2 is a longitudinal sectional view taken along line II-II in FIG.
The geothermal turbine 1 is, for example, for rotationally driving a generator (not shown) in a power plant. A turbine rotor 3 is pivotally supported inside a truncated cone-shaped turbine casing 2, and a steam chamber is provided at one end of the turbine casing 2. A casing 4 is installed.

  The turbine rotor 3 has a configuration in which multi-stage turbine blades 7 a to 7 f are rotatably integrated with the turbine shaft 6, and the turbine blade 7 a closest to the steam chamber casing 4 is the first stage turbine. The outer diameters of the turbine blades 7a to 7f are increased in the order of 7a → 7f.

  On the other hand, on the inner peripheral surface of the turbine casing 2, multi-stage nozzle ports 8 a to 8 f that overlap each other in front of the turbine blades 7 a to 7 f are provided, and the nozzle port 8 a positioned closest to the steam chamber casing 4 is the first stage. Nozzle opening. The opening areas of the nozzle ports 8a to 8f increase in the order of 8a → 8f, and overlap the upstream sides of the blade portions of the turbine blades 7a to 7f, respectively.

  As shown in FIG. 2, the steam chamber casing 4 has an annular shape surrounding the turbine rotor 3 (turbine shaft 6), and a first stage nozzle port 8a is formed along the circumferential direction thereof. In addition, the rotation direction of the turbine rotor 3 (turbine shaft 6) is clockwise toward FIG.

  The inside of the steam chamber casing 4 is partitioned by, for example, two flat partition walls 11 and 12, whereby a main steam chamber 14 having a large volume and a sub steam chamber 15 having a smaller volume than the main steam chamber 14. Is defined. The sub-steam chamber 15 having a small volume is provided near the uppermost portion in the vertical direction of the steam chamber casing 4.

  The partition walls 11 and 12 are viewed in the axial direction of the turbine rotor (see FIG. 2), and the rotation direction of the turbine rotor 3 (toward FIG. 2) is based on the vertical center line C passing through the axis O of the turbine shaft 6, respectively. It is fixed at a predetermined position in the circumferential direction of the steam chamber casing so as to form a sandwiching angle θ centered on the axis O in both the clockwise direction and the reverse direction (counterclockwise toward FIG. 2). ing. Then, the fixed positions of the partition walls 11 and 12 can be changed at the design stage of the geothermal turbine 1 in the circumferential direction of the steam chamber casing 4 so that the sandwiching angle θ changes. Thereby, the volume ratio between the main steam chamber 14 and the sub steam chamber 15 can be appropriately set and changed according to the specifications of the geothermal turbine 1.

  The volume of the main steam chamber 14 (the angle excluding the sandwiching angle θ × 2 times) is such that the output of the geothermal turbine 1 due to the provision of the sub-steam chamber 15 is not greatly reduced, and the main steam chamber 14 is connected to the turbine casing. 2 is set so that a rated output of 100% can be obtained only by the amount of geothermal steam supplied to 2.

Furthermore, since the amount of geothermal steam ejected from the first stage nozzle port 8a is different in the circumferential direction, it causes repetitive load on the moving blade row of the first stage turbine 7a, but the repetitive load is sufficiently allowable. Possible values are:
The volume of the sub-steam chamber 15 (the sandwich angle θ × 2 times the angle) is set. In the present embodiment, the sandwiching angle θ is preferably 15 ° to 25 °, and more preferably 15 ° to 20 °.

  On the other hand, for example, two main steam pipes 18 for supplying geothermal steam are connected to the main steam chamber 14 from below. The main steam pipe 18 is a pipe (not shown) that is equally branched into two at the upstream portion, and the main steam chamber is sandwiched between the turbine shaft 6 when viewed in the axial direction of the turbine shaft 6 (see FIG. 2). 14 on both sides. Further, the main steam pipe 18 has a vertical center line passing through the axial center line O so that geothermal steam is supplied as uniformly as possible to each first stage nozzle port 8 a provided along the circumferential direction of the main steam chamber 14. It is installed so as to be an axis object centering on C. In the present embodiment, the two main steam pipes 18 are connected. However, for example, the main steam pipe 18 may be one according to the specifications of the geothermal turbine 1.

  Further, a sub-steam pipe 19 that connects between the main steam chamber 14 and the sub-steam chamber 15 is provided. The sub-steam pipe 19 is a pipe that distributes a part of the geothermal steam supplied from the main steam pipe 18 to the main steam chamber 14 to the sub-steam chamber 15, and an opening / closing valve 20 is provided at an intermediate portion thereof. It is preferable that the on-off valve 20 can be reliably opened and closed with a simple and simple structure as much as possible so as not to hinder the opening and closing operation due to the influence of the scale in the geothermal steam.

  The auxiliary steam pipe 19 extends from the main steam chamber 14 at a position higher than the axial center line O of the turbine shaft 6 and is curved along the rotation direction of the turbine rotor 3 (clockwise toward FIG. 2). It extends upward and is connected to the sub-steam chamber 15 provided near the uppermost portion of the steam chamber casing 4 from above. The on-off valve 20 is provided in the vicinity of the uppermost vertical portion of the auxiliary steam pipe 19.

  As described above, the position where the sub steam pipe 19 extends from the main steam chamber 14 is set to a position higher than the axis O of the turbine shaft 6, and the sub steam pipe 19 is set along the rotational direction of the turbine rotor 3. Of the plurality of first-stage nozzle ports 8 a along the circumferential direction of the main steam chamber 14, the steam on the upstream side of the main steam chamber 14 having a higher pressure is easily supplied to the sub steam chamber 15. For this reason, the influence of the pressure loss by the steam flow of the sub steam piping 19 can be reduced.

  The steam chamber 21 includes the steam chamber casing 4, the partition walls 11 and 12, the main steam chamber 14, the sub steam chamber 15, the main steam pipe 18, the sub steam pipe 19, and the valve 20. ing.

The geothermal turbine 1 including the steam chamber 21 configured as described above is operated as follows.
In FIG. 3, the geothermal turbine 1 can obtain a rated output of 100% shown on the vertical axis of FIG. 3 only by the amount of geothermal steam supplied from the main steam chamber 14 to the turbine casing 2. For this reason, the on-off valve 20 is kept closed until a predetermined operation time, for example, 12 months elapses from the start of operation (point A), and geothermal steam does not flow from the main steam chamber 14 to the sub steam chamber 15. Thus, driving is performed.

  After the operation is started, impurities such as scale contained in the geothermal steam begin to accumulate in the first stage nozzle port 8a of the main steam chamber 14, so that the opening area of the first stage nozzle port 8a of the main steam chamber 14 becomes narrower in FIG. As indicated by line B and line B ′, the output of the geothermal turbine 1 decreases. For example, when the operation period is 12 months, the output of the geothermal turbine 1 decreases by about 15% and decreases to about 85% of the rated output (point C).

  Generally, in a geothermal turbine power plant, if the output of the geothermal turbine 1 is reduced to about 80% of the rated output, it will hinder the maintenance of the total power generation considering the load change operation. The on-off valve 20 is opened at a point in time (for example, when it drops to about 85% of the rated output). As a result, part of the geothermal steam supplied to the main steam chamber 14 is distributed to the sub-steam chamber 15 and the sub-steam chamber 15 is operated, and the geothermal steam is also supplied from the first stage nozzle port 8a of the sub-steam chamber 15 to the turbine casing 2. To be supplied. It is preferable to stop the operation of the geothermal turbine 1 when the on-off valve 20 is opened.

  When the sub steam chamber 15 operates, the output of the geothermal turbine 1 rises and recovers to the rated output (point D in FIG. 3). After that, the output again decreases as shown by line E, but the opening / closing valve 20 is opened when the first stage nozzle port 8a of the sub-steam chamber 15 narrows due to the accumulation of impurities and the output decreases to 85% of the rated output. For example, about 12 months later. In other words, from the start of operation up to 24 months (F point), it is not necessary to open and disassemble the geothermal turbine 1 and perform maintenance, thereby increasing the operating rate of the geothermal turbine plant (such as a geothermal power plant). it can.

  In the steam chamber 21 of the geothermal turbine 1, a part of the geothermal steam supplied from the main steam pipe 18 to the main steam chamber 14 is distributed to the sub steam chamber 15 via the sub steam pipe 19. For this reason, a pressure loss occurs in the sub-steam pipe 19, and due to this pressure loss, the amount (pressure) of geothermal steam supplied to the sub-steam chamber 15 becomes smaller than the geothermal steam supplied to the main steam chamber 14.

  When the output of the turbine is lowered and the sub steam chamber 15 is operated, that is, when the on-off valve 20 provided in the sub steam pipe 19 is opened, the opening of the first stage nozzle port 8a of the main steam chamber 14 where impurities are accumulated. The area is narrow, and the opening area of the first stage nozzle port 8a of the sub-vapor chamber 15 where no impurities are deposited remains large.

  Here, the amount of steam ejected from the first stage nozzle port 8a of the main steam chamber 14 during operation of the sub steam chamber 15 (or the amount of steam per moving blade row) and the steam ejected from the first stage nozzle port 8a of the sub steam chamber 15 When comparing the amount (or the amount of steam per moving blade row), it is desirable that both are as much as possible.

  In the initial stage of the operation start of the geothermal turbine 1, the opening area of the first stage nozzle port 8 a of the main steam chamber 14 is in a wide state, and the sub steam chamber 15 is not in operation, that is, the geothermal steam from the first stage nozzle port 8 a of the sub steam chamber 15. Has not erupted. For this reason, there is a difference between the amount of steam ejected from the first stage nozzle port 8a of the main steam chamber 14 and the amount of steam ejected from the first stage nozzle port 8a of the sub steam chamber 15 (= 0). It causes repetitive load on the rotor blade row. However, the volume of the sub-steam chamber 15 (the sandwich angle θ × 2 times the angle), that is, the volume ratio with respect to the main steam chamber 14 is set so that this repeated load can be sufficiently tolerated.

  As time elapses after the geothermal turbine 1 starts operation, impurities such as scale gradually accumulate in the first stage nozzle port 8a of the main steam chamber 14, the opening area becomes narrower, and the amount of steam ejected from here (( Alternatively, the steam amount per moving blade row) decreases, and the output of the geothermal turbine 1 decreases. Therefore, as described above, the on-off valve 20 is opened and the sub-steam chamber 15 is operated, and geothermal steam is also supplied from the first stage nozzle port 8a of the sub-steam chamber 15 to the turbine casing 2 side to recover the output of the geothermal turbine 1. Is planned.

  At this time, the opening area of the first stage nozzle port 8 a of the sub steam chamber 15 is larger than the opening area of the first stage nozzle port 8 a where the scale of the main steam chamber 14 is deposited, but the geothermal steam flowing into the sub steam chamber 15. Is lower than the pressure in the main steam chamber 14 due to the pressure loss due to the passage resistance between the sub steam pipe 19 and the on-off valve 20.

  Therefore, the amount of steam ejected from the first stage nozzle port 8a of the main steam chamber 14 (or the amount of steam per moving blade row) and the amount of steam ejected from the first stage nozzle port 8a of the sub steam chamber 15 (or per moving blade row). The amount of steam) is approximately the same, and the geothermal turbine 1 is in a well-balanced state. For this reason, steam is uniformly supplied from the first stage nozzle ports 8a of both the main steam chamber 14 and the sub steam chamber 15 along the circumferential direction of the first stage turbine 7a, and the repeated load on the rotor blade row of the first stage turbine 7a is generated. Generation can be reduced. That is, it is preferable that the generation of repeated loads on the rotor blade row of the first stage turbine 7a does not increase rather than the initial stage of the operation start of the geothermal turbine 1, but rather decreases.

  In addition, since the auxiliary steam pipe 19 for supplying the steam to the sub steam chamber 15 extends from the steam chamber casing 4 and is connected to the steam chamber casing 4 again, the length of the auxiliary steam pipe 19 is shortened. Therefore, the steam chamber casing 4 and the sub-steam pipe 19 can be integrated (modularized), thereby transporting and installing to the installation site, and sub-steam pipes. 19 piping works can be made easy.

  Further, the steam chamber 21 of the geothermal turbine 1 changes the fixing position of the partition walls 11, 12 defining the sub steam chamber 15 in the circumferential direction, so that the sandwiching angle θ of the sub steam chamber 15, that is, the main steam chamber 14 is changed. The capacity of the sub steam chamber 15 can be changed and set. For this reason, the positions of the partition walls 11 and 12 can be set in accordance with the positions of the plurality of first-stage nozzle ports 8a formed in the steam chamber casing 4, thereby reducing the output due to the installation of the sub steam chamber 15 (partition walls 11 and 12). Can be avoided.

  Further, the steam chamber 21 has a sub-steam chamber 15 provided near the uppermost portion of the steam chamber casing 4, and the sub-steam pipe 19 extends from the main steam chamber 14 at a position higher than the axis O of the turbine shaft 6. The sub-steam chamber 15 is connected to the sub-steam chamber 15 from above by extending and making a U-turn, and the on-off valve 20 is connected to the vicinity of the uppermost part of the sub-steam pipe 19. Because of this layout, even when steam condenses inside the sub-steam pipe 19, drain water does not accumulate, thereby simplifying the work of draining the drain water in the sub-steam pipe 19 before opening the sub-steam chamber 15 ( Or can be omitted).

[Second Embodiment]
FIG. 4 is a longitudinal sectional view of the steam chamber casing 4 showing the second embodiment of the present invention.
In the configuration in this figure, the configuration of the first embodiment shown in FIG. 2 is different from that in the steam chamber casing 4 of the steam chamber 21 among the partition walls 111 and 112 that define the sub steam chamber 15. The only difference is that the partition wall 111 positioned on the advance side in the rotational direction of the rotor 3 (the turbine shaft 6) is bent or curved, and the rest of the configuration is the same as that of FIG. The reference numerals are attached and the description is omitted.

  The partition wall 111 is bent so that the sandwiching angle of the sub steam chamber 15 around the axis O of the turbine rotor 3 is different between the outer peripheral side and the inner peripheral side of the partition wall 111. Specifically, the partition wall 111 is bent in a step shape (stepped shape) so that the radially inner portion 111b of the partition wall 111 is located on the more advanced side in the rotational direction of the turbine rotor 3 than the radially outer portion 111a. Thus, the sandwiching angle θ2 of the radially inner portion 111b is larger than the sandwiching angle θ1 of the radially outer portion 111a. It is conceivable that the same type of molding is performed not only on the partition wall 111 but also on the partition wall 112.

  As described above, by setting the sandwiching angle θ2 of the radially inner portion 111b of the partition wall 111 to be larger than the sandwiching angle θ1 of the radially outer portion 111a, the shape of the partition 111 is changed to the shape of the moving blade of the first-stage turbine 7a and the arrangement thereof. Accordingly, the flow of steam ejected from the first stage nozzle port 8a can be adapted to the moving blade shape and arrangement of the first stage turbine 7a. That is, the flow of the steam injected from the first stage nozzle port 8a to the first stage turbine 7a side is not hindered by the partition wall 111 (112), thereby reducing the turbine output due to the installation of the sub steam chamber 15 (partition wall 111 (112)). It can be avoided.

In particular, by forming the partition wall 111 in a step shape or by setting the sandwich angle to θ1 <θ2, the shape of the partition wall 111 can be easily added to the rotor blade shape of the first stage turbine 7a, and the above-described effect Can help.
The shape and arrangement of the rotor blades of the first stage turbine 7a differ depending on the specifications of the geothermal turbine 1 and do not necessarily have the same design. However, it is appropriate to provide the partition wall 111 (112) with bent shapes and sandwiching angles θ1 and θ2. It can correspond to.

[Third Embodiment]
FIG. 5 is a longitudinal sectional view of the steam chamber casing 4 showing the third embodiment of the present invention.
In the configuration in this figure, the configuration of the first embodiment shown in FIG. 2 is different from that of the first embodiment in that an on-off valve 20 is provided in an intermediate portion of a sub-steam pipe 19 connecting the main steam chamber 14 and the sub-steam chamber 15. Instead, only the flow rate adjustment valve 22 is provided, and the other configuration is the same as the configuration of FIG.

  When a part of the geothermal steam supplied to the main steam chamber 14 is distributed from the sub-steam pipe 19 to the sub-steam chamber 15 and the sub-steam chamber 15 is operated as the rated output of the geothermal turbine 1 decreases, the sub-steam chamber 15 is opened and closed. The opening degree of the flow rate adjusting valve 22 provided instead of the valve 20 is gradually opened. This makes it possible to introduce steam into the sub-steam chamber 15 while continuing the operation of the geothermal turbine 1, so that it is not necessary to stop the operation of the geothermal turbine 1, and the operability is improved, which is preferable.

  Further, since the flow rate adjusting valve 22 can adjust the flow rate, the amount of steam flowing from the sub steam pipe 19 into the sub steam chamber 15 is determined according to the performance degradation state from the rating of the geothermal turbine 1 and the required output load state. Can be adjusted appropriately.

  As described above, according to the steam chamber 21 of the geothermal turbine, the geothermal turbine 1 having the geothermal turbine, and the steam supply method of the geothermal turbine according to the present invention, the main steam chamber 14 and the sub steam chamber 15 are operated when the sub steam chamber 15 is in operation. It is possible to supply steam uniformly from both the first stage nozzle ports 8a of the steam chamber 15 along the circumferential direction of the first stage turbine 7a, thereby reducing the occurrence of repeated loads on the moving blade row of the first stage turbine 7a. Moreover, the installation work and piping work of the geothermal turbine 1 can be facilitated, the output reduction due to the installation of the sub-steam chamber 15 can be avoided, and the work of draining drain water can be simplified.

  It should be noted that the present invention is not limited to the configuration of the above-described embodiment, and can be appropriately modified or improved within a scope not departing from the gist of the present invention. Are also included in the scope of rights of the present invention.

DESCRIPTION OF SYMBOLS 1 Geothermal turbine 3 Turbine rotor 4 Steam chamber casing 7a First stage turbine 8a First stage nozzle port 11, 12, 111, 112 Partition 14 Main steam chamber 15 Sub steam chamber 18 Main steam pipe 19 Sub steam pipe 20 On-off valve (valve)
21 Steam chamber 22 Flow control valve (valve)
C Vertical center line passing through axis of turbine rotor O Center axis of turbine rotor θ Angle of sub steam chamber

Claims (8)

A steam chamber casing which is an annular shape surrounding the turbine rotor and in which a first stage nozzle port is formed along the circumferential direction;
A partition that divides the interior of the steam chamber casing into a main steam chamber and a sub steam chamber having a smaller volume than the main steam chamber;
A main steam pipe for supplying geothermal steam to the main steam chamber;
A sub-steam pipe connecting the main steam chamber and the sub-steam chamber, and distributing a part of the geothermal steam supplied to the main steam chamber to the sub-steam chamber;
A valve provided in the auxiliary steam pipe;
A steam chamber of a geothermal turbine characterized by comprising:   The partition wall is centered on the axial center line in the rotational direction of the turbine rotor and in the opposite direction with respect to a vertical center line passing through the axial center line of the turbine rotor as viewed in the axial direction of the turbine rotor. It is fixed at a predetermined position in the circumferential direction of the steam chamber casing so as to form a sandwich angle, and the fixed position of the partition wall can be changed in the circumferential direction of the steam chamber casing so that the sandwich angle changes. The steam chamber of the geothermal turbine according to claim 1.   The steam chamber of the geothermal turbine according to claim 2, wherein the partition wall is bent or curved so as to follow a blade shape of a moving blade row of a first stage turbine provided in the turbine rotor. The sub steam chamber is provided near the uppermost vertical portion of the steam chamber casing,
The sub steam pipe extends from the main steam chamber from a position higher in the vertical direction than the axial center line of the turbine rotor, and is connected to the sub steam chamber from vertically above,
4. The steam chamber of the geothermal turbine according to claim 1, wherein the valve is provided in the vicinity of a vertical uppermost portion of the sub-steam pipe.   The steam valve of the geothermal turbine according to any one of claims 1 to 4, wherein the valve is a flow rate adjusting valve.   A geothermal turbine comprising the steam chamber of the geothermal turbine according to any one of claims 1 to 5.   The interior of the steam chamber casing, which is an annular shape surrounding the turbine rotor and provided with the first stage nozzle ports along the circumferential direction thereof, is divided into a main steam chamber and a sub steam chamber having a smaller volume than the main steam chamber. A steam supply method for a geothermal turbine, wherein a part of the geothermal steam supplied to the main steam chamber is distributed to the sub steam chamber.   At the start of operation of the geothermal turbine, the geothermal steam is supplied from only the main steam chamber to the turbine rotor side, and when a predetermined operation time has elapsed from the start of operation or when the output of the geothermal turbine has decreased by a predetermined amount The steam supply method for a geothermal turbine according to claim 7, wherein a part of the geothermal steam supplied to the main steam chamber is distributed to the sub-steam chamber.

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