Condenser, geothermal power plant, and condenser operation method

Abstract

To provide a condenser which is less likely to overturn and enables reduction of the weight, and to provide a geothermal power plant and an operation method of the condenser.SOLUTION: Steam discharged from an axial flow turbine, which is rotationally driven around a rotation axis R extending in a predetermined direction by steam jetted from a geothermal well, is supplied to a condenser 10 through a steam duct 31. The condenser 10 includes: a body part 10a in which an outer shape of a cross section cut on a horizontal surface is circular and which is connected with the steam duct 31 and supplied with the steam discharged from the axial flow turbine through the steam duct 31 and cools the steam therein to condense the steam; and fixing parts 10b which fix the body part 10a.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a condenser, a geothermal power plant, and a method of operating a condenser. [Background technology]

[0002] In geothermal power plants, steam separated from geothermal fluid (mainly a mixture of steam and hot water) spewing from a well is introduced into a steam turbine to generate electricity. After the steam has completed its work in the steam turbine, it is guided to a condenser. The steam guided to the condenser is condensed by heat exchange with cooling water. For example, the one described in Patent Document 1 is known as a steam turbine and a condenser provided in a power plant.

[0003] Patent Document 1 describes a condenser having a condenser shell and an intermediate shell. The condenser shell and intermediate shell are arranged parallel to the turbine rotation axis direction along the turbine rotation axis direction. A steam turbine installed on a foundation is connected to a turbine connection opening of the intermediate shell. The condenser shell condenses turbine exhaust gas flowing in from the steam turbine. The condenser shell has a shape such that the cross section when cut horizontally is rectangular. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-223309 A Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, in geothermal power plants, the outer shape of the condenser is selected depending on the exhaust direction of the steam turbine. When an axial flow turbine is used, in which the exhaust direction is parallel to the turbine axis, a condenser with a rectangular cross section when cut on a horizontal plane, such as the condenser described in Patent Document 1 (hereinafter referred to as a "rectangular condenser"), is selected.

[0006] During operation of an axial flow turbine, a horizontal tensile stress (vacuum load) acts on the connection part with the steam turbine due to the vacuum load generated by the rotation drive. Because of this, an overturning moment occurs on the entire condenser, so a rectangular condenser with a structure and sturdy reinforcement capable of withstanding this overturning moment was adopted.

[0007] However, because of its sturdy structure, the rectangular condenser is about twice as heavy as a round condenser (a condenser whose cross section when cut horizontally is circular), which increases the costs of manufacturing in the factory, materials, transportation, and on-site installation. On the other hand, the circular condenser has the advantage of being lighter because it requires less reinforcement against the vacuum during operation compared to the rectangular condenser, but it has the problem that it is prone to tipping over when an overturning moment is applied because of its light weight. For this reason, it has been difficult to connect a circular condenser to an axial turbine.

[0008] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a condenser, a geothermal power plant, and a method for operating a condenser that can be made lighter. Another object of the present invention is to provide a condenser, a geothermal power plant, and a method for operating a condenser that are less likely to tip over. [Means for solving the problem]

[0009] In order to solve the above problems, the condenser, geothermal power plant, and condenser operation method of the present disclosure employ the following measures. A condenser according to one embodiment of the present disclosure is a condenser to which steam discharged from an axial flow turbine that is driven to rotate around a rotation axis extending in a predetermined direction by steam ejected from a geothermal well is supplied via a steam duct, the condenser having a circular cross-sectional outline when cut on a horizontal plane, and comprising: a main body to which the steam duct is connected and to which the steam discharged from the axial flow turbine is supplied via the steam duct, and which condenses the steam by cooling the steam inside, and a fixing part for fixing the main body.

[0010] A method of operating a condenser according to one embodiment of the present disclosure is a method of operating a condenser to which steam discharged from an axial flow turbine that is driven to rotate about a rotation axis extending in a predetermined direction by steam ejected from a geothermal well is supplied via a steam duct, the condenser having a circular cross-sectional outline when cut on a horizontal plane, and comprising: a main body to which the steam duct is connected and to which the steam discharged from the axial flow turbine is supplied via the steam duct, and a fixing part for fixing the main body, and comprising a step of condensing the steam by cooling the steam inside the main body. Effect of the Invention

[0011] According to the present disclosure, the weight of the condenser can be reduced and the condenser can be made less likely to tip over. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a geothermal power plant according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a diagram showing a schematic configuration of a condensate system according to an embodiment of the present disclosure. [Diagram 3] FIG. 1 is a schematic front view illustrating a steam turbine and a condenser according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a schematic perspective view illustrating a condenser and a gas cooler according to an embodiment of the present disclosure. [Diagram 5] FIG. 2 is a cross-sectional view of a condenser according to an embodiment of the present disclosure. [Figure 6]6 is a view of the reinforcing leg in FIG. 5 as viewed from the direction of arrow B. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments of a condenser, a geothermal power plant, and a condenser operation method according to the present disclosure will be described with reference to the drawings. The condenser 10 can be widely applied to a geothermal power plant 1 that generates power using geothermal fluid fume from a borehole 2, and is not limited to application to a geothermal power plant 1 having the configuration described below.

[0014] FIG. 1 is a diagram showing a schematic configuration of a geothermal power plant 1 according to a first embodiment of the present disclosure. In this embodiment, a case where one borewell 2 and one reinjection well 3 are provided will be described, but a plurality of borewells 2 and a plurality of reinjection wells 3 may be provided. Note that the geothermal power plant 1 shown in FIG. 1 is a flash cycle type geothermal power plant, but the condenser 10 can be similarly applied to geothermal power plants of other configurations, such as a binary cycle type. In addition, the condenser 10 can be similarly applied not only to geothermal power plants, but also to cases where heat is utilized from high-temperature fluids containing sulfur sulfide, such as geothermal steam.

[0015] As shown in FIG. 1, the geothermal power plant 1 of this embodiment mainly comprises a geothermal fluid transport pipe (gas-liquid two-phase fluid transport pipe) 5, a steam flow control valve (hereinafter simply referred to as the "flow control valve") 4, a steam-water separator (hereinafter referred to as the "separator 6") 6, a hot water pipe 7, a steam pipe 8, a steam turbine (axial flow turbine) 9, and a condensate system 20.

[0016] Geothermal fluid transport pipe 5 is a pipe that guides geothermal fluid spouted from borehole (geothermal well, production well) 2 to separator 6. A magma reservoir is formed underground below borehole 2, and rainwater that seeps underground and groundwater that flows in are heated by the heat of the magma reservoir to form a geothermal reservoir. Geothermal fluid is stored in the geothermal reservoir and is extracted to the surface by borehole 2. Geothermal fluid transport pipe 5 transports geothermal fluid from the geothermal reservoir to separator 6 via borehole 2. Note that geothermal fluid is a gas-liquid two-phase mixture fluid that is mainly composed of steam and hot water.

[0017] A flow control valve (fumarole flow control valve) 4 is provided on a geothermal fluid transport pipe 5 and adjusts the total flow rate (fumarole volume, total flow rate of steam and hot water) of the geothermal fluid flowing from the well 2 to the separator 6. The wellhead pressure of the well 2 can also be adjusted by adjusting the flow control valve 4.

[0018] In addition, an on-off valve (not shown) may be provided on the upstream side of the geothermal fluid flow on the geothermal fluid transport pipe 5 (near the outlet of the borehole 2) to control the flow state (flowing state or non-flowing state) of the geothermal fluid.

[0019] The separator 6 is a device that separates the geothermal fluid, which is a gas-liquid two-phase mixture fluid supplied through the geothermal fluid transport pipe 5, into steam and hot water. The hot water separated by the separator 6 is guided to a hot water pipe 7, and the steam separated by the separator 6 is guided to a steam pipe 8.

[0020] The hot water pipe 7 is a pipe that guides the hot water separated by the separator 6 to the reinjection well 3. By returning the hot water to the underground geothermal reservoir via the reinjection well 3, depletion of geothermal fluid in the underground geothermal reservoir is suppressed. The hot water separated by the separator 6 is pumped to the reinjection well 3 via the hot water pipe 7, for example, a pump (not shown). A plurality of reinjection wells 3 may be provided.

[0021] The steam pipe 8 is a pipe that guides the steam separated by the separator 6 to the steam turbine 9. When multiple separators 6 are provided, the steam separated by each separator 6 is joined in the steam pipe 8 and supplied to the steam turbine 9.

[0022] The steam turbine 9 is rotationally driven by the geothermal fluid spouted from the borehole 2 performing work on the turbine blades. Specifically, the turbine blades (not shown) are rotationally driven about a rotating shaft (not shown) by the energy of the steam separated from the hot water by the separator 6 and supplied through the steam pipe 8, and a generator (not shown) connected to the rotating shaft of the turbine blades is rotationally driven to generate electricity.

[0023] The condensation system 20 is a system for condensing the steam that has completed its work in the steam turbine 9. Fig. 2 is a diagram showing a schematic configuration of the condensation system 20. As shown in Fig. 2, the condensation system 20 includes a condenser 10, a cooling tower 16, a gas cooler (gas cooler) 11, an intercondenser (middle stage cooler) 13, and an after-condenser (rear stage cooler) 15. Note that the gas cooler 11 may be configured integrally as a part of the condenser 10. The condenser 10, the gas cooler 11, the intercondenser 13, and the after-condenser 15 function as heat exchangers.

[0024] In Fig. 2, the system through which the cooling water flows is the cooling water system. Since cooling water is used in the condensation system 20, the system through which the cooling water flows in the condensation system 20 is the cooling water system. More specifically, the cooling water system is made up of the condenser 10, the cooling tower 16, the gas cooler 11, the intercondenser 13, the after-condenser 15, the circulation system 17, and the supply system 18 (including other piping through which the cooling water flows). Note that in this embodiment, the cooling water system has the configuration shown in Fig. 2, but the configuration of the cooling water system is not limited to that in Fig. 2, and the system through which the cooling water flows is the cooling water system.

[0025] The condenser 10 condenses the steam discharged from the steam turbine 9 by bringing it into contact with cooling water. Specifically, the condenser 10 is a device that sprays cooling water onto steam (turbine exhaust steam) that has completed its work of rotating turbine blades (not shown) in the steam turbine 9, thereby cooling and condensing the steam to condense it. That is, the condenser 10 is of a direct contact type. Since the steam discharged from the steam turbine 9 contains non-condensable gases (carbon dioxide, hydrogen sulfide, etc.), in the following description, the fluid discharged from the steam turbine 9 will be referred to as "gas" or "steam (gas)". The condensed water is supplied to the cooling tower 16 by the condensation pump 19 via the circulation system 17. The steam (gas) containing the non-condensable gases that have not been condensed is supplied to the gas cooler 11.

[0026] The cooling tower 16 is a device that evaporates and cools the water condensed in the condenser 10. Specifically, water supplied to the cooling tower 16 is sprayed from the top of the cooling tower 16. A part of the sprayed water evaporates when it comes into contact with air circulated by the blower 21 of the cooling tower 16, and the latent heat associated with this evaporation cools the remaining water. The cooled water is stored in a water tank of the cooling tower 16 as cooling tower water. The cooling tower water stored in the water tank is supplied to the condenser 10 as cooling water via a supply system 18. The supply system 18 is also connected to the gas cooler 11, the intercondenser 13, and the after-condenser 15, and supplies cooling water to each device.

[0027] The gas cooler (other device) 11 is provided downstream of the gas flow with respect to the condenser 10. A supply system 18 that supplies cooling water to the upper part of the gas cooler 11 is connected to the gas cooler 11. The gas cooler 11 cools and condenses the gas using the cooling water. The gas cooler 11 is of a tray type as shown in FIG. 2. Note that FIG. 2 shows a structure of three trays (upper tray, middle tray, lower tray) as an example of the tray type, but the number of trays is not limited to three trays as long as there is at least one tray. Note that it is also possible to apply a gas cooler 11 of another configuration, such as a packed bed type. In the gas cooler 11, cooling water is supplied from the upper part of the housing of the gas cooler 11, and the cooling water accumulates in the upper tray (first tray) T1 (liquid phase). The cooling water is dispersed like rain and falls from a plurality of holes provided in the upper tray T1 to the lower side of the upper tray T1. The cooling water that falls collects in the middle tray (second tray) T2, and similarly to the upper tray T1, the cooling water is dispersed and falls from multiple holes provided in the middle tray T2. The cooling water that falls then collects in the lower tray (third tray) T3, and similarly to the upper tray T1 and middle tray T2, the cooling water is dispersed and falls from multiple holes provided in the tray T3.

[0028] In this way, the gas is cooled by contacting the cooling water falling inside the gas cooler 11. The cooling water and water produced by condensation accumulate at the bottom of the gas cooler 11 and are supplied to the cooling tower 16 by the circulation system 17.

[0029] The intercondenser 13 is provided downstream of the gas flow with respect to the gas cooler 11. The gas discharged from the gas cooler 11 is pressure-fed to the intercondenser 13 by the ejector 12. As shown in FIG. 1, steam is partially supplied to the ejector 12 through a pipe branched from the steam pipe 8, and the gas is pressure-fed using the steam. In the intercondenser 13, cooling water is sprayed from the top and comes into contact with the gas to cool it. The cooling water and water generated by condensation of the steam are accumulated in the lower part of the intercondenser 13 and are discharged from the intercondenser 13 as drain. The drain discharged from the intercondenser 13 may be supplied to a cooling tower 16 by a circulation system 17. The gas is discharged from the intercondenser 13 to an after-condenser 15 described later.

[0030] The after-condenser 15 is provided downstream of the inter-condenser 13 in the gas flow. The gas discharged from the inter-condenser 13 is pressure-fed to the after-condenser 15 by the ejector 14. As shown in FIG. 1, steam is partially supplied to the ejector 14 through a pipe branched from the steam pipe 8, and the gas is pressure-fed using the steam. In the after-condenser 15, cooling water is sprayed from the top and comes into contact with the gas to cool it. The cooling water and water generated by condensation of the steam and the gas accumulate in the lower part of the after-condenser 15 and are discharged from the after-condenser 15 as drain. The drain discharged from the after-condenser 15 may be supplied to a cooling tower 16 by a circulation system 17. The gas is discharged from the after-condenser 15 to the atmosphere. The ejector 14 may be replaced with, for example, a water-sealed vacuum pump, in which case the after-condenser 15 becomes a seal water separator.

[0031] The gas discharged from the after-condenser 15 has a high ratio of non-condensable gas components because water vapor has been removed by each device. The gas discharged from the after-condenser 15 may be released into the atmosphere together with the air used for cooling in the cooling tower 16, or may be subjected to other treatments.

[0032] Next, the steam turbine 9, the condenser 10, and the gas cooler 11 will be described in detail with reference to FIGS.

[0033] As shown in Fig. 3, the steam turbine 9 is provided on a foundation 30 formed on the ground 100. The steam turbine 9 is driven to rotate about a rotation axis R extending in a predetermined direction by steam (gas) ejected from a geothermal well. The steam turbine 9 discharges steam so that it flows parallel to the rotation axis R. The steam turbine 9 is a so-called axial flow turbine.

[0034] An upstream end of a steam duct 31 is connected to the downstream side of the steam turbine 9. Steam (gas) discharged from the steam turbine 9 flows inside the steam duct 31. As shown in Figs. 3 and 4, the steam duct 31 is a duct having a flow passage cross section of a substantially circular shape. The steam duct 31 extends linearly along the rotation axis R. That is, the steam duct 31 is disposed such that the central axis of the steam duct 31 is coaxial with the rotation axis R. 4, an atmosphere relief plate 32 (safety valve) is provided in the middle of the steam duct 31. When the pressure inside the steam duct 31 rises excessively, the atmosphere relief plate 32 is opened to reduce the pressure inside. The downstream end of the steam duct 31 is connected to the main body 10a of the condenser 10. In detail, a duct opening (not shown) is formed in the lower part of the downstream end of the steam duct 31, and this duct opening is connected to a condenser opening (not shown) formed in the upper end of the main body 10a of the condenser 10.

[0035] 3, the steam (gas) discharged from the steam turbine 9 flows through the steam duct 31 along the rotation axis R. The steam (gas) that has flowed through the steam duct 31 changes its flow direction downward as shown by the arrow G2, passes through the duct opening and the condenser opening, and flows into the condenser 10 from above. In this way, the steam (gas) discharged from the steam turbine 9 is supplied to the condenser 10 via the steam duct 31.

[0036] As shown in Fig. 3, the condenser 10 is installed upright on the ground 100. As shown in Fig. 4, the condenser 10 has a main body 10a that condenses the steam (gas) by cooling the steam (gas) therein, and a plurality of fixing legs (fixing portions) 10b that fix the main body 10a to the ground 100.

[0037] As shown in FIG. 5, the main body 10a has a circular cross-sectional shape when cut on a horizontal plane. As shown in FIG. 3 and FIG. 4, the main body 10a is a cylindrical member with a central axis C extending vertically. A space is formed inside the main body 10a. As shown in FIG. 2, the main body 10a sprays cooling water onto steam (gas) inside. This cools the steam (gas) to condense it and generate condensate. In this way, the condenser 10 according to this embodiment is a so-called round condenser in which the main body 10a that generates condensate has a circular cross-sectional shape when cut on a horizontal plane. The main body 10a has three ribs 10c protruding from the outer circumferential surface. Each rib 10c is provided over substantially the entire circumferential area. The three ribs 10c are arranged vertically at substantially equal intervals. Each rib 10c reinforces the main body 10a.

[0038] A steam duct 31 is connected to the upper end of the main body 10a. As shown in Fig. 5, the main body 10a and the steam duct 31 are arranged such that the central axis (i.e., the rotation axis R) of the steam duct 31 overlaps with the center point P of the main body 10a in a plan view. Also, as shown in Fig. 4, a notch is formed at the upper end of the main body 10a so as to be recessed downward from the upper end. The steam duct 31 fits into this notch. The main body 10a and the steam duct 31 are fixed by welding or the like so that no gap is generated between them.

[0039] As shown in FIG. 4, two supply systems 18 are connected to the side of the upper part of the main body 10a. As shown in FIG. 2, cooling water is supplied to the main body 10a by the supply system 18. Also, as shown in FIG. 4, two circulation systems 17 are connected to the side of the lower part of the main body 10a. As shown in FIG. 2, the circulation system 17 guides the condensate generated in the main body 10a to the cooling tower 16. Also, a non-condensing gas duct (connection part) 33 is connected to the side of the lower part of the main body 10a. In detail, the non-condensing gas duct 33 is connected to the side of the main body 10a opposite to the side where the steam turbine 9 is present. Also, the non-condensing gas duct 33 is arranged so that the central axis is coaxial with the central axis of the steam duct 31 (i.e., the rotation axis R) when the main body 10a is viewed in a plane. The non-condensing gas duct 33 connects the condenser 10 and the gas cooler 11. The non-condensed gas duct 33 guides the steam (gas) that is not condensed in the condenser 10 to the gas cooler 11.

[0040] The fixed legs 10b are provided on the lower part of the outer circumferential surface of the main body 10a, as shown in Fig. 4 and Fig. 5. The fixed legs 10b (10 in this embodiment, for example) are arranged side by side in the circumferential direction. The fixed legs 10b are arranged at unequal intervals. As shown in Fig. 5, the fixed legs 10b are arranged symmetrically with respect to the rotation axis R. The fixed legs 10b are also arranged symmetrically with respect to the intersection line L. The intersection line L is a virtual line that passes through the center point P and is perpendicular to the rotation axis R.

[0041] The fixed legs 10b include a fixed leg (fixed portion) 10bA on the rotation axis side closest to the rotation axis R, a fixed leg (fixed portion) 10bB on the crossing line side closest to the crossing line L, and an intermediate fixed leg (intermediate fixed portion) 10bC provided between the fixed leg 10bA on the rotation axis side and the fixed leg 10bB on the crossing line side. In this embodiment, the fixed leg 10bB on the crossing line side is provided so as to overlap with the crossing line L, for example. In each fixed leg 10b, the intermediate fixed leg 10bC is disposed closer to the fixed leg 10bA on the rotation axis side than the fixed leg 10bB on the crossing line side. That is, the circumferential distance between the intermediate fixed leg 10bC and the fixed leg 10bA on the rotation axis side is shorter than the circumferential distance between the intermediate fixed leg 10bC and the fixed leg 10bB on the crossing line side. In other words, the intervals at which the fixed legs 10b are provided are shorter in the region on the rotation axis R side (region closer to the rotation axis R than the intersecting line L). Note that it is preferable to provide a plurality of fixed legs 10b so as not to interfere with the circulation system 17, the gas cooler 11, and other components disposed on the outer circumferential surface of the condenser 10. The intersecting line side fixed legs 10bB do not necessarily need to be provided so as to overlap the intersecting line L, and the rotation axis side fixed legs 10bA may be provided including on the rotation axis R.

[0042] Since each of the fixed legs 10b has the same structure, the following description will be given of one of the fixed legs 10b as a representative example. As shown in Figures 4 and 6, the fixed leg 10b integrally has two vertical plate portions 10ba extending in the vertical direction, a bottom surface portion 10bb connecting the lower ends of the two vertical plate portions 10ba, and an upper surface portion 10bc connecting the upper ends of the two vertical plate portions 10ba.

[0043] The two vertical plate portions 10ba are arranged at a predetermined distance apart in the circumferential direction of the condenser 10. Each vertical plate portion 10ba is a plate-shaped member that protrudes radially outward from the outer circumferential surface of the main body portion 10a. Each vertical plate portion 10ba is arranged so that its plate surface is a vertical plane. The inner end of each vertical plate portion 10ba is fixed to the outer circumferential surface of the main body portion 10a. As shown in FIG. 6, each vertical plate portion 10ba has a trapezoidal shape in which the radial length of the upper edge is shorter than the radial length of the lower edge in a side view. The lower end of each vertical plate portion 10ba is fixed to the upper surface of the bottom surface portion 10bb. The upper end of each vertical plate portion 10ba is fixed to the lower surface of the upper surface portion 10bc.

[0044] The bottom surface portion 10bb is a plate-shaped member that protrudes radially outward from the outer circumferential surface of the main body portion 10a. The bottom surface portion 10bb is disposed so that the plate surface is a horizontal plane. The bottom surface portion 10bb is disposed so that the lower surface thereof contacts the ground 100. The bottom surface portion 10bb is fixed to the ground 100 by a plurality of bolts (not shown) that penetrate in the vertical direction.

[0045] The top surface portion 10bc is a plate-like member that protrudes radially outward from the outer circumferential surface of the main body portion 10a. The top surface portion 10bc is disposed so that the plate surface is a horizontal plane.

[0046] 4, the gas cooler 11 is disposed and fixed on the side opposite to the side on which the steam turbine 9 is present, across the condenser 10. That is, the gas cooler 11 is provided on the radially outer side of the condenser 10.

[0047] A non-condensed gas duct 33 is connected to the gas cooler 11 on the side facing the condenser 10. The non-condensed gas duct 33 is disposed and fixed on the side opposite to the side where the steam turbine 9 is present, sandwiching the condenser 10 therebetween. The gas cooler 11 has a circular cross-sectional outer shape when cut on a horizontal plane. The gas cooler 11 is a cylindrical member whose central axis extends along the up-down direction. The upper end of the gas cooler 11 is closed by the ceiling surface portion 11b. A closed space is formed inside the gas cooler 11. The ceiling surface portion 11b has a rib 11c provided on its upper surface. The rib 11c is erected on the upper surface of the ceiling surface portion 11b. The rib 11c is a plate-shaped rib arranged in a lattice pattern. The rib 11c reinforces the ceiling surface portion 11b. Since the gas cooler 11 or the non-condensing gas duct 33 is disposed radially outside the condenser 10, the main body 10a is less likely to tip over due to its weight. In addition, since the gas cooler 11 or the non-condensing gas duct 33 is disposed and fixed on the opposite side of the condenser 10 from the side where the steam turbine 9 is located, tip-over can be prevented more effectively.

[0048] Two ribs 11a protruding from the outer peripheral surface of the gas cooler 11 are provided on the outer peripheral surface. Each rib 11a is provided over substantially the entire circumferential area. The two ribs 11a are arranged next to each other in the up-down direction at a predetermined interval. Each rib 11a reinforces the gas cooler 11.

[0049] A gas pipe 35 is connected to the side of the upper part of the gas cooler 11. As shown in Fig. 2, the gas pipe 35 guides steam (gas) that is not condensed even in the gas cooler 11 to the ejector 12. In addition, a supply system 18 is connected to a ceiling surface portion 11b of the gas cooler 11. As shown in Fig. 2, cooling water is supplied to the gas cooler 11 by the supply system 18.

[0050] According to this embodiment, the following advantageous effects are obtained. Hereinafter, a condenser having a main body 10a whose horizontal cross section has a circular outer shape will be referred to as a "round condenser." Also, a condenser having a main body whose horizontal cross section has a rectangular outer shape will be referred to as a "rectangular condenser."

[0051] In this embodiment, the condenser 10 is a round condenser. This can improve the strength of the main body 10a against the internal and external pressure difference, for example, compared to a case where a rectangular condenser is used as the condenser 10. Therefore, it is not necessary to provide a structure (for example, an increase in plate thickness or a reinforcing material) for improving the strength against the internal and external pressure difference, and the weight of the main body 10a can be reduced. In addition, the manufacturing cost of the main body 10a can be reduced. As a result, the weight of the condenser can be reduced, and the manufacturing cost of the condenser and the installation cost of the geothermal power plant 1 can be reduced.

[0052] Furthermore, when the steam turbine 9, which is an axial flow turbine, is rotated, a tensile load (see arrow A1 in FIG. 3) acts on the steam duct 31 due to the influence of a vacuum load generated by the rotation of the steam turbine 9. As a result, a tensile load also acts on the main body 10a to which the steam duct 31 is connected, via the steam duct 31. Due to this tensile load, an overturning moment (see arrow A2 in FIG. 3) acts on the main body 10a, but in this embodiment, the main body 10a is fixed to the ground 100 by a plurality of fixing legs 10b, so that the main body 10a is less likely to overturn.

[0053] As described above, generally, a round condenser is prone to tipping over due to the tipping moment when connected to an axial turbine due to its light weight, etc., but in this embodiment, the condenser 10, which is a round condenser, is fixed to the ground 100 by the fixing legs 10b, so that the condenser 10 is less likely to tip over even when connected to the steam turbine 9, which is an axial turbine. In this manner, in this embodiment, a structure is provided that suppresses the tipping over of the condenser 10, so that a round condenser can be adopted as the condenser 10 connected to the steam turbine 9, which is an axial turbine, and the weight and manufacturing cost of the condenser 10 can be reduced. In addition, the installation cost of the geothermal power plant 1 can be reduced.

[0054] In this embodiment, the multiple fixing legs 10b are arranged in a line along the circumferential direction on the outer circumferential surface of the main body 10a, and are arranged symmetrically with respect to the rotation axis R. This makes the load acting on each fixing leg 10b uniform. This makes it possible to suppress localized concentration of the load, and therefore the main body 10a can be fixed more firmly.

[0055] In this embodiment, the intermediate fixed legs 10bC are disposed closer to the rotation axis side fixed legs 10bA than the intersection line side fixed legs 10bB. That is, the intervals at which the fixed legs 10b are provided are shorter in the region on the rotation axis R side (the region closer to the rotation axis R than the intersection line L). This increases the number of fixed legs 10b near the rotation axis R where a large overturning moment acts. This allows the main body 10a to be fixed more firmly.

[0056] In this embodiment, the gas cooler 11 provided radially outside the main body 10a is connected to the main body 10a by the non-condensing gas duct 33. This makes it possible to prevent the main body 10a from tipping over due to the weight of the gas cooler 11.

[0057] The present disclosure is not limited to the invention according to the above-described embodiments, and various modifications are possible without departing from the spirit and scope of the present disclosure.

[0058] For example, in the above embodiment, the steam duct 31 is connected to the upper end of 10a, and steam is supplied from above to the main body 10a of the condenser 10, but the present disclosure is not limited to this. For example, the steam duct 31 may be connected to a side of the main body 10a, and steam may be supplied from the side to the main body 10a of the condenser 10.

[0059] In addition, for example, in the above embodiment, the main body 10a has a cross-sectional shape that is circular when cut on a horizontal plane, but the present disclosure is not limited to this. For example, the main body 10a may have a cross-sectional shape that is elliptical, oval, or rectangular when cut on a horizontal plane.

[0060] Also, for example, in the above embodiment, the number of fixing legs 10b is 10, but the present disclosure is not limited to this. For example, the number may be 9 or less, or 11 or more. In order to fix the condenser 10, which is a round condenser, it is preferable to provide 8 or more fixing legs 10b so that the condenser 10 can be suitably fixed to the ground 100.

[0061] The condenser, the geothermal power plant, and the method of operating the condenser described in the above-described embodiments can be understood, for example, as follows. A condenser according to one embodiment of the present disclosure is a condenser (10) to which steam discharged from an axial flow turbine (9) which is driven to rotate about a rotation axis (R) extending in a predetermined direction by steam ejected from a geothermal well (2) is supplied via a steam duct (31), the condenser having a circular cross-sectional outline when cut on a horizontal plane, and comprising: a main body portion (10a) to which the steam duct (31) is connected and to which the steam discharged from the axial flow turbine (9) is supplied via the steam duct (31), and which condenses the steam by cooling the steam inside, and a fixing portion (10b) for fixing the main body portion (10a).

[0062] In the above configuration, the cross section of the main body when cut on a horizontal plane (hereinafter referred to as the "horizontal cross section") has a circular outer shape. This improves the strength of the main body against the internal and external pressure difference, for example, compared to when the horizontal cross section has a rectangular outer shape. Therefore, the main body can be made lighter by not needing to provide a structure for improving the strength against the internal and external pressure difference (for example, an increased plate thickness or a reinforcing material). In addition, the manufacturing cost of the main body can be reduced. As a result, the condenser can be made lighter and its manufacturing cost can be reduced. When the axial flow turbine rotates, a tensile load acts on the steam duct due to the vacuum load generated by the rotation of the axial flow turbine. Therefore, the tensile load also acts on the main body to which the steam duct is connected via the steam duct. This tensile load causes an overturning moment to act on the main body, but in the above configuration, the main body is fixed by the fixing part, making it difficult for the main body to overturn. As described above, a main body having a circular outer shape in horizontal cross section is prone to tipping over due to an overturning moment when connected to an axial turbine due to reasons such as its light weight, but in the above configuration, the main body is fixed by the fixing part, so that the main body is less likely to tip over even when connected to an axial turbine. In this manner, in the above configuration, by making the main body less likely to tip over, it is possible to employ a main body having a circular outer shape in horizontal cross section as a condenser to be connected to an axial turbine, thereby making it possible to reduce the weight and manufacturing costs of the condenser. An axial flow turbine is a device in which steam flowing in parallel to the axis of rotation collides with the turbine blades, transferring the energy of the steam to the rotor and being discharged in a direction parallel to the axis.

[0063] In the condenser according to the aspect of the present disclosure, the fixing portion (10b) fixes the main body to the ground. In the above-described configuration, the main body can be fixed to the ground. This makes it possible to fix the main body firmly, and makes it more difficult for the main body to tip over.

[0064] In addition, in the condenser according to one embodiment of the present disclosure, the fixed portions (10b) are provided in plurality, the main body portion (10a) is arranged so that the rotation axis (R) overlaps on a center point (P) in a plan view, and the fixed portions (10b) are arranged along the circumferential direction on the outer circumferential surface of the main body portion (10a) and are arranged symmetrically with respect to the rotation axis (R).

[0065] In the above configuration, the multiple fixing parts are arranged in a line along the circumferential direction on the outer circumferential surface of the main body, and are arranged symmetrically with respect to the rotation axis. This makes it possible to equalize the load acting on each fixing part. This makes it possible to suppress localized concentration of the load, and therefore to more firmly fix the main body. The rotation axis includes both the rotation axis included in the axial flow turbine and a line extending from the rotation axis included in the axial flow turbine.

[0066] In addition, in a condenser according to one embodiment of the present disclosure, the fixed portions (10b) are provided in plurality, the main body portion (10a) is arranged so that the rotation axis (R) overlaps on a center point (P) when viewed in a plane, and the multiple fixed portions (10b) are provided along the circumferential direction on the outer circumferential surface of the main body portion (10a), and have a rotation axis side fixed portion (10bA) closest to the rotation axis (R), a cross line side fixed portion (10bB) closest to a cross line (L) perpendicular to the rotation axis (R), and an intermediate fixed portion (10bC) provided between the rotation axis side fixed portion (10bA) and the cross line side fixed portion (10bB), and the intermediate fixed portion (10bC) is arranged closer to the rotation axis side fixed portion (10bA) than the cross line side fixed portion (10bB).

[0067] In the above configuration, the intermediate fixing portion is disposed closer to the rotation axis side fixing portion than the intersection line side fixing portion. That is, the intervals at which the fixing portions are provided are shorter in the region on the rotation axis side (the region closer to the rotation axis than the intersection line). This results in a greater number of fixing portions in the vicinity of the rotation axis where a large overturning moment acts. Therefore, the main body can be fixed more firmly.

[0068] In the condenser according to one aspect of the present disclosure, another device (11) is fixed to the main body (10a) and is provided radially outward of the main body (10a).

[0069] In the above-described configuration, the main body is fixed to the other device provided radially outward from the main body, thereby making it difficult for the main body to tip over due to the weight of the other device. One example of such other device is a gas cooler that cools steam containing non-condensable gases that were not condensed in the condenser.

[0070] In addition, in the condenser according to one embodiment of the present disclosure, the other device (11) is fixed to the main body portion (10a) via a connection portion (33), and the connection portion (33) is connected to an outer circumferential surface of the main body portion on a side opposite to the axial flow turbine (9).

[0071] In the above configuration, the other device is connected to the side opposite to the axial flow turbine via the connection part, which makes it possible to make the main body less likely to tip over against the tipping moment acting due to the tensile load from the axial flow turbine.

[0072] In addition, a geothermal power plant according to one embodiment of the present disclosure includes the axial flow turbine (9) that is rotationally driven by the steam ejected from a geothermal well (2), a generator connected to the axial flow turbine (9) and generating electricity using the driving force of the axial flow turbine (9), and a condenser (10) described in any one of the above that generates condensate by cooling the steam discharged from the axial flow turbine (9).

[0073] Furthermore, a method for operating a condenser according to one embodiment of the present disclosure is a method for operating a condenser (10) in which steam discharged from an axial flow turbine (9) that is driven to rotate about a rotation axis (R) extending in a predetermined direction by steam ejected from a geothermal well (2) is supplied to the condenser (10) via a steam duct (31), the condenser (10) having a cross-sectional shape that is circular when cut on a horizontal plane, the condenser (10) comprising: a main body (10a) to which the steam duct (31) is connected and to which the steam discharged from the axial flow turbine (9) is supplied via the steam duct (31); and a fixing part (10b) that fixes the main body (10a), and the method for operating a condenser (10) comprises a step of condensing the steam by cooling the steam inside the main body (10a). [Explanation of symbols]

[0074] 1: Geothermal power plant 2: Well 3: Reinjection well 4: Flow control valve 5: Geothermal fluid transport pipe 6: Separator 7:Hot water pipe 8: Steam pipe 9: Steam turbine (axial flow turbine) 10: Condenser 10a: Main body 10b: Fixed leg (fixed part) 10bA: Rotation axis side fixed leg (rotation axis side fixed part) 10bB: Cross line side fixed leg (cross line side fixed part) 10bC: Intermediate fixed leg (intermediate fixed part) 10ba: Vertical plate section 10bb: Bottom part 10bc:Top part 10c: Rib 11: Gas cooler (other equipment) 11a: Rib 11b:Ceiling surface part 11c: Rib 12: Ejector 13: Inter-capacitor 14: Ejector 15: After-condenser 16: Cooling tower 17: Circulatory system 18: Supply system 19: Condensate pump 20: Condensate system 21: Blower 30: Basics 31: Steam duct 32: Air release plate 33: Non-condensing gas duct 35: Gas piping 100: Ground T1: Top tray T2: Middle tray T3: Lower tray

Claims

1. A condenser to which steam discharged from an axial flow turbine that is driven to rotate about a rotation axis extending in a predetermined direction by steam ejected from a geothermal well is supplied via a steam duct, a main body having a circular cross section when cut on a horizontal plane, the main body being connected to the steam duct, the steam discharged from the axial flow turbine being supplied thereto via the steam duct, and the main body cooling the steam therein to condense the steam; A fixing portion that fixes the main body portion, The fixing portion is provided in plurality, A condenser, wherein the fixing portions are arranged along a circumferential direction on an outer circumferential surface of the main body.

2. The condenser according to claim 1 , wherein the fixing portion fixes the main body to the ground.

3. The main body is arranged so that the rotation axis overlaps a center point when viewed in a plane, 3. The condenser according to claim 1, wherein the plurality of fixing portions are arranged symmetrically with respect to the rotation axis.

4. The main body is arranged so that the axis of rotation overlaps a center point when viewed in a plane, the plurality of fixing portions include a rotation axis side fixing portion closest to the rotation axis, a cross line side fixing portion closest to a cross line perpendicular to the rotation axis, and an intermediate fixing portion provided between the rotation axis side fixing portion and the cross line side fixing portion, 4. The condenser according to claim 1, wherein the intermediate fixed portion is disposed closer to the rotation axis side fixed portion than the intersecting line side fixed portion.

5. The condenser according to claim 1 , wherein another device is fixed to the main body portion radially outward of the main body portion.

6. the other device is fixed to the main body via a connection part, The condenser according to claim 5 , wherein the connection portion is connected to an outer circumferential surface of the main body portion on an opposite side to the axial flow turbine.

7. the axial flow turbine that is rotationally driven by the steam ejected from the geothermal well; a generator connected to the axial flow turbine and configured to generate electricity using a driving force of the axial flow turbine; 7. A geothermal power plant comprising: the condenser according to claim 1, which generates condensate by cooling the steam discharged from the axial flow turbine.

8. A method for operating a condenser in which steam discharged from an axial flow turbine that is driven to rotate about a rotation axis extending in a predetermined direction by steam ejected from a geothermal well is supplied to the condenser through a steam duct, the method comprising the steps of: The condenser is a main body having a circular cross section when cut on a horizontal plane, the main body being connected to the steam duct and receiving the steam discharged from the axial flow turbine via the steam duct; A fixing portion that fixes the main body portion, The fixing portion is provided in plurality, The fixing portions are arranged along a circumferential direction on an outer circumferential surface of the main body portion, A method of operating a condenser comprising the step of condensing the steam by cooling the steam inside the main body.

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