Power generation system and power generation method

Abstract

To provide a power generation system and a power generation method that can convert the kinetic energy at the time of discharging sediment deposited in a dam reservoir into electric energy and effectively utilize the energy at the time of sediment discharge.SOLUTION: A system 20 for generating electricity using sediment S deposited on a water bottom comprises: a sand discharge path 21 for discharging the sediment S deposited on the water bottom to an opposite side to the water bottom with an embankment body 7 interposed between them as a sand discharge flow S1; and a power generation device 22 provided in the sand discharge path 21 and converting the kinetic energy of the sand discharge flow S1 into electrical energy.SELECTED DRAWING: Figure 3

Description

Technical Field

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[0003]

[0001] The present disclosure relates to a power generation system and a power generation method.

Background Art

[0002] Conventionally, dams for power generation, flood control (flood regulation), irrigation, water supply, industrial use, etc. form a reservoir (water storage area including a water storage lake) in the upper reaches of the dam by blocking the river channel with a dam body. As a result, sediment such as sand accumulates on the bottom of the reservoir.

[0003] Sediments such as sand, gravel, stones (rocks), and driftwood deposited on the bottom, which are called "sand deposits", cause a decrease in the water storage capacity of the dam. In addition, they gradually develop upstream from near the dam body, leading to an increase in the water level in the upper reaches during floods and can be a factor in flooding damage. In recent years, in many dams, the amount of sand deposits tends to increase due to heavy rain frequently occurring due to abnormal weather, exceeding the planned amount at the time of dam construction.

[0004] On the other hand, if the supply of sediment from the upstream to the downstream is completely blocked by the dam, many adverse effects will occur, such as scouring of the riverbed in the downstream of the dam, retreat of the coastline, disappearance of the sandy beach, collapse of the revetment, changes in ocean currents and river flows, increase in flood damage, and impact on the ecosystem.

[0005] Therefore, it is important to discharge a certain amount of sand deposits in the upper reaches of the dam to the lower reaches of the dam. Many techniques have been proposed and put into practical use as sediment discharge methods (for example, see Patent Document 1). For example, a method of dredging sand deposits using a dredger equipped with a grab bucket, a backhoe, a pump, etc., and transporting and discharging them from the upper reaches of the dam to the lower reaches of the dam; a method of providing a sediment discharge path by penetrating or bypassing the dam body, and further providing a sediment discharge gate in the sediment discharge path, and discharging the sand deposits to the lower reaches of the dam through the sediment discharge path as appropriate when they have accumulated to a certain thickness and height, etc. have been put into practical use.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-201083 [Overview of the project] [Problems that the invention aims to solve]

[0007] In power generation dams, as is well known, water is taken from the reservoir, which is held back and stored by the dam body, through an intake, and is also sent and released downstream of the dam by gravity flow utilizing the head difference (potential energy). The kinetic energy during this sending and releasing of water is used to rotate a turbine and generate electricity.

[0008] In contrast, sediment accumulates at the bottom of reservoirs, resulting in low potential energy. Furthermore, it is difficult to allow it to flow naturally at high flow rates and velocities like water. Moreover, the frequency of sediment removal is low, depending on the progression of sediment accumulation. Generally, it is done only every few months at most, usually every few years, and in some cases every several decades. Consequently, there is little thought given to effectively utilizing the kinetic energy of sediment removal and release. As a result, the potential energy of sediment removal, which requires considerable labor and equipment costs, is wasted.

[0009] In view of the above circumstances, this disclosure aims to provide a power generation system and power generation method that convert the kinetic energy of removing sediment accumulated in a dam reservoir into electrical energy, thereby enabling the effective utilization of the energy used during sediment removal. [Means for solving the problem]

[0010] (1) One aspect of the power generation system of the present disclosure is a power generation system for generating electricity using sediment deposited at the bottom of a dam reservoir, comprising: a sediment discharge channel for discharging the sediment deposited at the bottom of the reservoir as a sediment discharge flow to the downstream side of the dam body; and a power generation device provided in the sediment discharge channel for converting the kinetic energy of the sediment discharge flow into electrical energy.

[0011] In this case, the force of the water stored in the reservoir to carry sediment (scalding force) is used to discharge the accumulated sediment along with the water as a sediment discharge flow through a sediment discharge channel, and a power generation device installed in the sediment discharge channel can convert the kinetic energy of the sediment discharge flow into electrical energy.

[0012] In this case, even if the potential energy of the sediment is small, the mass of the sediment and, consequently, the sediment discharge flow is greater than that of water, resulting in greater kinetic energy for the sediment discharge flow. Therefore, even when using sediment with low potential energy, it is possible to achieve power generation efficiency equivalent to, or even higher than, that of hydroelectric power generation.

[0013] Therefore, according to one embodiment of the power generation system of this disclosure, it becomes possible to generate electricity by effectively utilizing the kinetic energy (latent energy of the sediment) during the removal of sediment that would otherwise be wasted by simply being discharged into the downstream area of ​​the dam. Furthermore, by combining hydroelectric power generation with power generation using dam sediment, the value of hydroelectric dams and multi-purpose dams can be increased.

[0014] (2) Another aspect of the power generation system of the present disclosure is that, in (1) above, the power generation device includes an impact power generation plate for causing the sand discharge flow to collide and converting the impact energy into power generation energy.

[0015] In this case, simply guiding the sediment discharge flow to collide with the impact generator plate makes it possible to achieve power generation that effectively utilizes the accumulated sediment. This makes it possible to generate electricity using sediment without incurring significant costs, resulting in a highly cost-effective solution and greatly increasing the applicability of the power generation system.

[0016] (3) Another embodiment of the power generation system of the present disclosure, in (2) above, the sediment discharge channel includes a sediment discharge pipe penetrating the dam body and a guide wall provided on the front of the dam body, which forms a sediment discharge channel that guides the sediment discharged from the outlet of the sediment discharge pipe to the downstream side of the dam body, wherein the impact power generation plate is attached to at least a portion of the wall surface of the guide wall.

[0017] In this case, it becomes possible to easily generate electricity using accumulated sediment simply by installing impact generator plates on the wall surface of the existing sediment removal facility's guide wall at the dam. This will make the system even more cost-effective and further enhance the applicability of power generation systems using dam sediment.

[0018] (4) Another embodiment of the power generation system of the present disclosure, in (1) above, comprises an impeller device that receives the sand discharge flow and rotates around an axis, and a power generation device body that generates electricity by the rotation of the impeller device.

[0019] In this case, similar to hydroelectric power generation, the kinetic energy of the sediment discharge flow can be used to rotate the impeller, and this rotational energy of the impeller can be converted into electrical energy by the power generation device itself to generate electricity.

[0020] (5) Another embodiment of the power generation system of the present disclosure is that, in (4) above, the power generation device comprises a crusher.

[0021] In this case, for example, a crusher is used as a power generation device, which comprises a rotating shaft that rotates around an axis by an electric motor, a blade that is coaxially connected to the rotating shaft and has a rotating blade (crushing blade) for crushing materials such as rocks as it rotates, and a robust housing that houses the rotating shaft and blade, has an input port for receiving the materials to be crushed, and an output port for discharging the crushed material as the blade rotates.

[0022] Specifically, for example, the inlet of the crusher becomes the outlet, and the outlet becomes the inlet. The sand flow is introduced into the housing from the inlet corresponding to the outlet of the crusher, and this is received by the impeller of the impeller device corresponding to the blades and rotating blades (crushing blades), which rotates the rotating shaft and, consequently, the main body of the power generation device corresponding to the electric motor of the crusher, thereby generating electricity.

[0023] This makes it unnecessary to newly research and develop a power generation device that has sufficient durability against the sand discharge flow from the beginning. Also, when discharging the deposited sand, by diverting / using the crusher of the crushing equipment that is previously provided as a dam facility, or by simply preparing a power generation device with specifications substantially equivalent to those of a crusher, a power generation device for dam deposited sand and thus a power generation system can be realized.

[0024] (6) Another aspect of the power generation system of the present disclosure is, in the above (1), the power generation device includes an endless belt that travels receiving the sand discharge flow, a rotating body that rotates by the travel of the endless belt, and a power generation device main body that generates electricity by the rotation of the rotating body.

[0025] In this case, the kinetic energy of the sand discharge flow can be used to run the endless belt and rotate the rotating body, and the rotational energy of the rotating body can be converted into electrical energy by the power generation device main body to generate electricity.

[0026] (7) Another aspect of the power generation system of the present disclosure is, in any of the above (4) to (6), the power generation device is arranged on the downstream side of the dam body.

[0027] In this case, for example, when installing a power generation system using dam deposited sand in an existing dam, the modification work on the existing dam, such as providing a sand discharge path in the existing dam body, is relatively less. Therefore, for example, it is relatively easy to install a power generation system using dam deposited sand in an existing dam.

[0028] (8) Another aspect of the power generation system of the present disclosure is, in any of the above (4) to (6), at least a part of the power generation device is arranged inside the dam body.

[0029] In this case, it is relatively easy to secure an installation space for the power generation device.

[0030] (9) One embodiment of the power generation method of the present disclosure is a power generation method that generates electricity using the power generation system described above, comprising: a sediment agitation step of loosening the sediment accumulated on the seabed at the seabed; a sediment discharge step of discharging the sediment loosened in the sediment agitation step as a sediment discharge flow in the sediment discharge channel together with the stored water; and a power generation step of converting the kinetic energy of the sediment discharge flow into electrical energy with the power generation device.

[0031] In this case, the effects of the above-mentioned power generation system can be obtained.

[0032] Furthermore, by incorporating a sediment agitation process to loosen the sediment accumulated at the bottom of the reservoir, the water pressure and flow force (scalding force) of the water stored in the reservoir can be used to effectively remove sediment over a wide area as a sediment discharge flow. Therefore, it becomes possible to eliminate dam operation processes during sediment discharge, such as lowering and restoring the reservoir water level, which require a great deal of time, observation, and management effort. This makes it possible to perform sediment discharge efficiently and effectively and generate electricity with the discharge flow. Thus, it becomes possible to achieve even more remarkable effects. [Effects of the Invention]

[0033] According to the power generation system and method disclosed herein, the kinetic energy generated when removing sediment accumulated in a dam reservoir is converted into electrical energy, making it possible to effectively utilize the energy generated during sediment removal. [Brief explanation of the drawing]

[0034] [Figure 1] This figure shows an example of a dam according to the first and second embodiments. [Figure 2] This figure shows an example of a hydroelectric power generation facility for a dam according to the first and second embodiments. [Figure 3] This figure shows an example of a power generation system using dam sediment according to the first embodiment. [Figure 4] This figure shows an example of a power generation system using dam sediment according to the first embodiment. [Figure 5]This figure shows an example of a power generation method using dam sediment according to the first and second embodiments, and is a diagram showing the sediment stirring process. [Figure 6] This figure shows an example of a power generation method using dam sediment according to the first and second embodiments, and is a diagram showing the sediment removal process. [Figure 7] This figure shows an example of a power generation system using dam sediment according to the second embodiment. [Figure 8] This is a semi-cross-sectional view showing an example of a crusher. [Figure 9] This is a semi-cross-sectional view showing an example of using a crusher as a power generation device. [Figure 10A] This diagram schematically shows the power generation system immediately before opening the sediment discharge gate in the sediment discharge process of the power generation method using dam sediment according to the second embodiment. [Figure 10B] This diagram schematically shows the power generation system when the sediment discharge flow begins during the sediment discharge process of the power generation method using dam sediment according to the second embodiment. [Figure 10C] This diagram schematically shows the power generation system when the sediment discharge flow begins to be discharged into the downstream area of ​​the dam during the sediment discharge process of the power generation method using dam sediment according to the second embodiment. [Figure 11] This figure shows an example of a power generation system using dam sediment according to the third embodiment. [Figure 12] This figure schematically shows the cross-section in the direction of arrow AA in Figure 11. [Figure 13] This figure shows an example of a power generation system using dam sediment according to the fourth embodiment. [Figure 14] This figure shows an example of a power generation system using dam sediment according to the fifth embodiment. [Figure 15] This figure shows a modified example of the power generation system using dam sediment according to the fifth embodiment. [Modes for carrying out the invention]

[0035] (First Embodiment) The following describes a power generation system using dam sediment and a power generation method using dam sediment according to one embodiment, with reference to Figures 1 to 6.

[0036] Firstly, as shown in Figures 1, 2, and 3, the dam 1 of this embodiment is, for example, a multi-purpose dam and is equipped with a hydroelectric power generation facility 2, a water discharge facility 3, and a sediment removal facility 4, which is a component of the power generation system using dam sediment of this embodiment. Here, "sediment removal" refers to the discharge of sediment and other materials accumulated at the bottom (bottom) 6 of the dam reservoir 5. However, "sediment removal" in this disclosure also includes so-called "sediment passage," which is the passage of sediment and other materials flowing into the dam reservoir 5. Furthermore, "sediment removal" in this disclosure includes not only soil and sand, but also gravel, stones (rocks), driftwood, and other materials.

[0037] As shown in Figures 1 and 2, the hydroelectric power generation facility 2 is configured to include, for example, an intake 8 for taking in water W from the reservoir 5 in the upstream area R1 of the dam, which is dammed by the embankment 7 of the dam 1; a water conduit 9 for sending the water W taken in at the intake 8; a water conduit gate 10 for opening and closing the water conduit 9; a turbine (impeller) 11 that rotates using the kinetic energy of the water W conduit 9; a generator 12 for converting the rotational energy of the turbine 11 into electrical energy; a transformer 13 for boosting the power generated by the generator 12; power transmission equipment 14 such as power lines and high-voltage towers for transmitting the power boosted by the transformer 13; and a discharge channel 15 for discharging the water W that has rotated the turbine 11 into the downstream area R2 of the dam.

[0038] The water conduit 9 does not need to be particularly limited in its configuration, as long as it can transport water W from the upstream area R1 of the dam to the downstream area R2 of the dam and allow it to flow naturally at the desired head. For example, the water conduit 9 is configured to include, as appropriate and selectively, a water conduit 16 that penetrates the dam body 7 from the front 7a to the back 7b and extends from the front 7a to the downstream area R2 of the dam, a water conduit that straddles the crest (top) 7c of the dam body 7 and extends to the downstream area R2 of the dam, a water conduit that bypasses the dam body 7 and extends to the downstream area R2 of the dam, or a water conduit (water conduit tunnel) that extends to the downstream area R2 of the dam through the ground G below the dam body 7.

[0039] As shown in Figures 1, 2, and 3, the discharge facility 3 is equipped with a discharge channel 17 for discharging water W from the upstream R1 side of the dam body 7, penetrating from the back surface 7b on the upstream R1 side to the front surface 7a on the downstream R2 side. The discharge channel 17 is appropriately and selectively provided with an emergency spillway (overflow spillway) located on the crest 7c side, a regular spillway located on the lower side of the dam body equipped with a conduit gate, and an emergency spillway located in the middle of the dam body equipped with an orifice gate. The discharge channel 17 is also equipped with a guide wall 18 for guiding the water W discharged from the spillway outlet, and an energy dissipator 19 for reducing the force of the discharged water W.

[0040] (Power generation system using dam sediment) As shown in Figures 1, 2, 3, and 4, the sediment removal facility 4 is equipped with a dam sediment power generation system 20 for generating electricity using the sediment S accumulated at the bottom 6 of the dam reservoir 5.

[0041] The power generation system 20 using dam sediment in this embodiment comprises a sediment discharge channel 21 for discharging sediment S accumulated on the bottom 6 of the dam reservoir 5 as a sediment discharge flow S1 to the downstream side (R2) of the dam body 7, and a power generation device 22 provided in the sediment discharge channel 21 for converting the kinetic energy of the sediment discharge flow S1 into electrical energy. The sediment S also includes sediment such as soil that flows into the dam reservoir 5.

[0042] The sediment discharge channel 21 of this embodiment is provided on the lower side of the dam body 7, for example, penetrating from the back surface 7b to the front surface 7a of the dam body 7, and includes a sediment discharge pipe (sediment discharge outlet) 21a for sending sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam, and a sediment discharge channel 21c for guiding the sediment discharge flow S1, which includes water W and sediment S discharged from the outlet 21b of the sediment discharge pipe 21a, to the downstream area R2 of the dam.

[0043] Furthermore, in this embodiment, the sediment discharge channel 21c is formed with a guide wall 21d.

[0044] In the power generation system 20 using dam sediment of this embodiment, a power generation device 22 for sediment discharge power generation, which converts the kinetic energy of the discharged sediment flow S1 into electrical energy, is provided in the sediment discharge channel 21c, and this power generation device 22 is configured to include a vibration power generation device (impact power generation plate) 23 for converting the fluid energy of the discharged sediment flow S1 into power generation energy.

[0045] Furthermore, the power generation device 22 for sand removal power generation is equipped with a transformer 13 for boosting the power generated by the vibration power generation device 23, and power transmission equipment 14 such as power lines and high-voltage towers for transmitting the power boosted by the transformer 13. These transformer 13 and power transmission equipment 14 may, of course, be provided in a manner that is also used for hydroelectric power generation equipment 2.

[0046] Furthermore, the power generated by the dam sediment power generation system 20 of this embodiment may be configured to be used within the dam facility.

[0047] Furthermore, the sediment discharge pipe 21a for sending sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam is not limited to a sediment discharge pipe 21a that penetrates the dam body 7. It may also be a sediment discharge pipe extending to the downstream area R2 of the dam by crossing the dam crest 7c, a sediment discharge pipe extending to the downstream area R2 of the dam by bypassing the dam body 7, or a sediment discharge pipe extending to the downstream area R2 of the dam through the ground G below the dam body 7, and these may be provided selectively as appropriate.

[0048] The vibration power generation device 23 does not need to be particularly limited in its configuration, as long as it is capable of converting the fluid energy of the sediment discharge flow S1 into power generation energy, or in other words, as long as it is capable of generating energy from the vibrations caused by the sediment discharge flow S1.

[0049] On the other hand, the vibration power generation device 23 of this embodiment is, for example, an impact power generation plate 24 attached to the wall surface of the guide wall 21d that forms the sediment discharge channel 21c, which collides with the sediment discharge flow S1 and converts the impact energy (fluid energy and vibration energy of the sediment discharge flow S1) into power generation energy.

[0050] Examples of vibration power generation devices for the shock power generation plate 24 include piezoelectric types that use piezoelectric elements to generate voltage when force is applied, magnetic types that generate voltage when a coil and magnet move relative to each other when force is applied, permanent charge types that generate voltage when an electrode plate with an attached charge moves when force is applied, and magnetostrictive types, which are known to be the main research and development being conducted by the Vibration Power Generation Laboratory, Department of Electronics, Information and Communication Engineering, Faculty of Science and Engineering, Kanazawa University, and in which magnetization (magnetic field lines) changes significantly when force is applied, and a voltage is generated by the magnetostrictive effect (inverse magnetostrictive effect).

[0051] (Power generation method using dam sediment) When generating electricity using the dam sediment power generation system 20 of this embodiment (in the dam sediment power generation method of this embodiment), first, as shown in Figure 5, the sediment S accumulated on the bottom 6 of the dam reservoir 5 is loosened at the bottom 6 (sediment stirring process).

[0052] Here, "loosening the sediment S" in this disclosure means reducing the load-bearing capacity of the solidified sediment layer and making it possible to remove the sediment S as a discharged sediment flow S1 in the discharge channel 21 by utilizing the force of the water flow (scouring force) in the subsequent sediment discharge process. For this reason, in the sediment agitation process, any means can be applied to reduce the load-bearing capacity of the sediment layer, such as drilling holes in the sediment layer and agitating it, or applying vibration to break it down.

[0053] More specific examples of loosening the sediment S (sediment agitation process) include mounting work equipment such as earth drills 27, deep mechanical agitators for ground improvement and pile driving, grab buckets, backhoes and other dredging equipment, and other work equipment with similar configurations or uses on floating bodies such as barges 25 and dredgers, or on fixed scaffolding installed and constructed at a designated location in the reservoir 5, and using these work equipment to agitate, drill, or break up the sediment S (sediment layer) on the bottom 6.

[0054] Then, as shown in Figures 3, 4, and 5 (Figure 1), the sediment discharge gate 26 is opened, and the water pressure of the water W stored in the reservoir 5 and the scavenging force of the water W carrying sediment are used to discharge the sediment S loosened in the sediment agitation process together with the water W as a sediment discharge flow S1 through the sediment discharge channel 21, and the sediment discharge flow S1 is discharged into the sediment discharge channel 21c (sediment discharge process). At the same time, the kinetic energy of the sediment discharge flow S1 flowing through the sediment discharge channel 21c is converted into electrical energy by the vibration power generation device 23 (impact power generation plate 24) (power generation process).

[0055] Therefore, according to the power generation system 20 using dam sediment and the power generation method using dam sediment of this embodiment, it becomes possible to generate electricity by effectively utilizing the kinetic energy (potential energy of sediment S) during the discharge of sediment S, which would otherwise be wasted by simply being discharged into the downstream area R2 of the dam.

[0056] Furthermore, it is possible to use both hydroelectric power generation and power generation using dam sediment, thereby increasing the value of dam 1 for hydroelectric power generation.

[0057] In the past, the kinetic energy of sediment removal was not utilized in sediment deposits S because they accumulated at the bottom 6 of the reservoir 5, resulting in low potential energy, and they could not be easily and freely flowed down at high flow rates and velocities like water W.

[0058] However, while the density of water W is 1 (ton / m³), the density of sand (sediment S) is, for example, 2-3 (ton / m³), and the density of the sediment discharge flow S1 containing sediment S and water W is also much larger than that of water W. Furthermore, when the mass is m (kg) and the velocity is v (m / s), the kinetic energy K can be expressed as K = 1 / 2 × m × v².

[0059] As a result, while hydroelectric power generation relies on the potential energy of water W to secure kinetic energy, in the power generation using sediment S in this embodiment, kinetic energy can be secured by the mass of the sediment S and, consequently, the sediment discharge flow S1, even if the potential energy is small. Therefore, in the power generation system 20 using dam sediment and power generation using dam sediment of this embodiment, even when using sediment S with low potential energy, it is possible to secure kinetic energy equivalent to that of hydroelectric power generation and to secure power generation efficiency equivalent to that of hydroelectric power generation.

[0060] Furthermore, in the power generation system 20 using dam sediment of this embodiment, the power generation device 22 is configured to include an impact power generation plate 24 that collides with the discharged sediment flow S1 and converts the impact energy into power generation energy. Therefore, by simply guiding the sediment discharge flow S1 to collide with the impact power generation plate 24, it becomes possible to realize power generation that effectively utilizes the accumulated sediment S.

[0061] Furthermore, in the power generation system 20 using dam sediment of this embodiment, the sediment discharge channel 21 comprises a sediment discharge pipe 21a that penetrates the dam body 7, and a guide wall 21d provided on the front surface 7a of the dam body 7, which forms a sediment discharge channel 21c that guides the sediment discharge flow S1 discharged from the outlet 21b of the sediment discharge pipe 21a to the downstream side R2 of the dam body 7, and is configured by attaching an impact power generation plate 24 to at least a part of the wall surface of the guide wall 21d. This makes it possible to easily realize power generation using sediment S simply by installing impact power generation plates 24 on the wall surface of the guide wall 21d of the existing sediment removal facility 4 of Dam 1. In other words, power generation using sediment S can be carried out without incurring significant costs, resulting in a very high cost-effectiveness and greatly increasing the applicability of the dam sediment power generation system 20.

[0062] Furthermore, when removing (clearing) sediment from a dam, it is usually necessary to carry out five dam operation steps in stages: (a) measures taken during flooding, (b) lowering the water level of reservoir 5, (c) natural flow of sediment S, (d) restoration of the water level of reservoir 5, and (e) measures taken after sediment removal. In contrast, the power generation method using dam sediment of this embodiment involves loosening the sediment S beforehand and using the water pressure and scouring force of the water flow stored in the reservoir W to remove the sediment. Therefore, it is possible to eliminate the two conventional dam operation processes of (b) lowering the water level of the reservoir 5 and (d) restoring the water level of the reservoir 5, which require a great deal of time and effort for observation and management. This makes it possible to remove sediment efficiently and effectively, and to generate electricity with the removed sediment flow S1. Thus, it becomes possible to achieve even more remarkable effects. In addition, in the power generation method using dam sediment of this embodiment, it is also possible to perform dam operation steps such as (b) lowering the water level of reservoir 5 and (d) restoring the water level of reservoir 5.

[0063] Furthermore, by loosening the accumulated sediment S beforehand, the range of influence of the scouring force on the sediment S, and consequently the range from which sediment can be removed, can be greatly expanded. Therefore, by simply taking the extra step of loosening the accumulated sediment S beforehand, it is possible to significantly improve the sediment removal efficiency and, consequently, the power generation efficiency.

[0064] In the power generation system 20 and power generation method using dam sediment of this embodiment, it is preferable to determine the timing of each process, etc., in order to suitably carry out sediment removal and power generation using sediment, taking into consideration the season (time of year), the state of sedimentation, the reservoir water level, the scouring force, the effect of sediment agitation, etc., as shown in Table 1.

[0065] [Table 1]

[0066] (Second Embodiment) Next, with reference to Figures 7, 8, and 9 (and Figures 1, 2, 5, and 6), a power generation system using dam sediment and a power generation method using dam sediment according to the second embodiment will be described. In this embodiment, some of the configurations of the sediment removal equipment 4 differ from those of the first embodiment. Therefore, the same reference numerals are used for components similar to those in the first embodiment, and detailed explanations are omitted.

[0067] (Power generation system using dam sediment) The sediment removal equipment 4 of this embodiment, like the first embodiment, includes a power generation system 20 that uses dam sediment to generate electricity using the sediment S accumulated at the bottom 6 of the dam reservoir 5.

[0068] Furthermore, as shown in Figure 7, the power generation system 20 using dam sediment in this embodiment is configured to include a sediment discharge channel 21 for discharging the sediment S accumulated on the bottom 6 of the dam reservoir 5 as a sediment discharge flow S1 to the downstream side R2 of the dam body 7, and a power generation device 22 provided in the sediment discharge channel 21 for converting the kinetic energy of the sediment discharge flow S1 into electrical energy.

[0069] On the other hand, the sediment discharge channel 21 in this embodiment is provided on the lower side of the dam body 7, for example, penetrating from the back surface 7b to the front surface 7a of the dam body 7, and is equipped with a sediment discharge pipe (sediment discharge outlet) 21a for sending sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam, and the outlet 21b of this sediment discharge pipe 21a is connected to the power generation device 22.

[0070] Furthermore, the sediment discharge pipe 21a for sending the sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam is not limited to a discharge pipe that penetrates the dam body 7, but is sufficient as long as it is capable of sending the sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam, and further to the power generation equipment 22. For example, it may be a discharge pipe that extends to the downstream area R2 of the dam by straddling the crest 7c of the dam body 7, a discharge pipe that extends to the downstream area R2 of the dam by bypassing the dam body 7, or a discharge pipe that extends to the downstream area R2 of the dam through the ground G below the dam body 7. In addition, the discharge pipe may be laid to send the dredged sediment S to the power generation equipment 22. Furthermore, these discharge pipes may be provided selectively as appropriate.

[0071] Next, the power generation device 22 of this embodiment is configured to include an impeller device 30 having an impeller 30a that rotates around its axis in response to the sand discharge flow S1, and a power generation device body 31 that generates electricity by the rotation of the impeller device 30. The power generation device body 31 can be a generator that generates electricity by the rotation of the impeller device 30, similar to the hydroelectric power generation equipment 2.

[0072] On the other hand, since the fluid that rotates the impeller device 30 is not water W, but sand, gravel, and in some cases a discharge flow S1 containing rocks with a diameter of, for example, 20-30 cm, there is a risk of damage, breakage, wear, etc., if the component configuration is the same as that of the hydroelectric power generation equipment 2, that is, there is a risk of durability problems.

[0073] Therefore, the power generation device 22 of this embodiment needs to be constructed using robust materials, particularly for the impeller device 30 and the housing that takes in the sediment discharge flow S1. However, researching and developing a power generation device 22 that has sufficient durability against the sediment discharge flow S1 from scratch requires considerable effort and cost.

[0074] In response to this, the inventor of the present application has diligently continued research as a dam engineer regarding the application of a crusher 40 as a power generation device 22, which comprises a rotating shaft 32 that rotates around axis O1 by an electric motor, a blade 34 that is coaxially connected to the rotating shaft 32 and has a rotating blade (crushing blade) 33 for crushing the object to be crushed M1 such as rock as it rotates, an impact plate 35 that impacts the object to be crushed M1 and crushes it together with the rotating blade 33, and a robust housing 38 that houses the rotating shaft 32, the blade 34 and the impact plate 35 and has an input port 36 for receiving the object to be crushed M1 and an output port 37 for discharging the processed material M2 after crushing as the blade 34 rotates. He has found that this crusher 40 is fully applicable and beneficial for a power generation system 20 using dam sediment.

[0075] Specifically, in dams such as multi-purpose dams (dam 1), there are many cases where rocks M1 flow from the upper reaches of the river into the dam reservoir (reservoir 5) due to heavy rain, typhoons, and the resulting flash floods and debris flows. Then, for example, when the water level in reservoir 5 is low or during a drought, the rocks M1 are recovered by sediment removal or dredging, and the recovered rocks M1 are crushed in a crusher (crusher 40) and used as aggregate for other construction work.

[0076] Furthermore, during dam construction, crushing equipment including a crusher 40 is installed to secure concrete aggregate, and this equipment is removed upon completion of dam construction. In addition, local aggregate plants are equipped with crushers 40. Therefore, dam engineers already possess knowledge and information regarding the specifications of a suitable crusher 40 for crushing the sediment S flowing into the reservoir 5.

[0077] The inventors of this invention focused on this point and invented a power generation system 20 and power generation method using dam sediment of this embodiment, which converts the kinetic energy of the discharged sediment flow S1 into electrical energy by repurposing (reusing) the crusher 40 of the crushing equipment or by preparing a new power generation device with specifications substantially equivalent to the crusher 40 when the sediment S is discharged, at most every few months, usually every few years, and in some cases every several decades.

[0078] A power generator 41 that repurposes the crusher 40 of the crushing equipment, or a power generator 41 with specifications roughly equivalent to those of the crusher 40, is configured such that, as shown in Figure 9, the inlet 36 of the crusher 40 shown in Figure 8 becomes the outlet 42, and the outlet 37 becomes the inlet 43 (a configuration similar to that of the crusher 40). Then, the discharged sand flow S1 is introduced into the housing 44 through the discharge pipe 21a from the inlet 43, which corresponds to the outlet 37 of the crusher 40, and is received by the impeller 46 of the impeller device 45, which corresponds to the blades 34 and the crushing blades (rotating blades) 33, and rotates the rotating shaft 47 (32), and consequently the power generator body (not shown), which corresponds to the electric motor of the crusher 40, to generate electricity.

[0079] Furthermore, it is preferable to control the rotational speed of the impeller device 45 with a speed governor to keep it as constant as possible, thereby enabling the generation of electricity with a stable frequency.

[0080] Furthermore, the main components of the power generation device (not shown) are, for example, an armature with windings, a stator with magnets and a yoke, a rotating shaft connected to the armature, bearings and a commutator, and terminals for extracting power. Such a power generation device is a generator, in which an impeller 46 and a rotating shaft 47 are connected to the rotating shaft or armature, and it is configured to convert the rotational energy of the impeller 46 and the rotating shaft 47 into electrical energy.

[0081] The sediment discharge flow S1 after the impeller device 45 has been rotated is then discharged from the outlet 42, which corresponds to the inlet 36 of the crusher 40, and released into the downstream area R2 of the dam.

[0082] (Power generation method using dam sediment) Furthermore, when generating electricity using the dam sediment power generation system 20 of this embodiment and the kinetic energy of the sediment discharge flow S1 (in the power generation method using dam sediment of this embodiment), as in the first embodiment, the sediment S accumulated on the bottom 6 of the dam reservoir 5 is first loosened at the bottom 6 (sediment stirring process: see Figure 5).

[0083] Then, the sediment discharge gate 26 is opened, and the water pressure W of the water stored in the reservoir 5 and the scavenging force of the water flow carrying sediment are used to discharge the sediment S loosened in the sediment agitation process, along with the stored water W, as a sediment discharge flow S1 through the sediment discharge pipe 21a (sediment discharge process). The sediment discharge flow S1 sent from the sediment discharge pipe 21a is received by the generator body (generator) of the power generation device 22, and the kinetic energy of this sediment discharge flow S1 is used to rotate the impeller device 45 to generate electricity, and the sediment discharge flow S1 is discharged into the downstream area R2 of the dam (power generation process: see Figure 6).

[0084] Here, for example, it is preferable that the power generation device body is configured such that the power generation device body 31 or the power generation device body 41 (not shown) can function as an electric motor by supplying power to the power generation device body from an external source. Then, in the sand removal process, it is preferable that the impeller devices 30 and 45 are rotated by supplying power to the power generation device body from an external source to drive the power generation device body. In other words, in the power generation system using dam sediment according to the second embodiment, the power generation device 22 is preferably configured to convert electrical energy into kinetic energy of the sediment discharge flow S1 by receiving a power supply. The following explanation of how to drive the power generation device by supplying power from an external source during the sand removal process will be given with reference to Figures 10A, 10B, and 10C.

[0085] Figure 10A is a schematic diagram showing the power generation system 20 immediately before opening the sediment discharge gate 26 in the sediment discharge process of the power generation method using dam sediment according to this embodiment. Figure 10B schematically shows the power generation system 20 when the sediment discharge flow S1 begins to flow during the sediment discharge process of the power generation method using dam sediment in this embodiment. Figure 10C schematically shows the power generation system 20 when the sediment discharge flow S1 begins to be discharged into the downstream area R2 of the dam during the sediment discharge process of the power generation method using dam sediment in this embodiment.

[0086] Figures 10A, 10B, and 10C illustrate the case where there is almost no sediment S in the sediment discharge channel 21 downstream of the sediment discharge gate 26 before the start of the sediment discharge process, that is, when the water W in the reservoir 5 has completely washed away the sediment S in the sediment discharge channel 21 in the previous power generation process, or when the sediment discharge process is being performed for the first time in the power generation system 20 of this embodiment. However, there may be sediment S remaining in the sediment discharge channel 21 downstream of the sediment discharge gate 26 before the start of the sediment discharge process.

[0087] In the sand removal process in this embodiment, when the sand removal gate 26 is opened from the state shown in Figure 10A, the water pressure of the water W stored in the reservoir 5 and the scavenging force of the water W carrying sediment and other materials cause the loosened sand S from the sand agitation process to begin flowing through the sand removal channel 21 (sand removal pipe 21a) as a sand removal flow S1 together with the stored water W. As shown in Figure 10B, it reaches the impeller device 30 or the crusher 40 and then flows further downstream through the sand removal channel 21 (sand discharge channel 21c). Furthermore, in the sand removal process in this embodiment, the supply of external power to the power generation device body 31 or power generation device 41 (not shown) is started at approximately the same time as the opening of the sand removal gate 26. As a result, the power generation device body is driven by the external power to rotate the impeller device 30 or the crusher 40. Therefore, even if the flow velocity of the sand removal flow S1 is relatively low in the initial stage of the sand removal process, kinetic energy is imparted to the sand removal flow S1 by the rotation of the impellers 30a and 46, making it easier for the sand removal flow S1 to flow within the sand removal channel 21. Furthermore, in order to prevent the impellers 30a and 46 from obstructing the flow of the sand discharge flow S1, the timing for starting the operation of the power generation device body by external power should be before the sand discharge flow S1 reaches the impeller device 30 or the crusher 40, that is, before the state shown in Figure 10B is reached.

[0088] Thus, in the power generation system using dam sediment according to the second embodiment, the power generation device body 31 or the power generation device 41 (not shown) is preferably configured to rotate the impeller devices 30 and 45 when it receives a power supply. Furthermore, in the power generation method using dam sediment in this embodiment, during the sediment discharge process, it is preferable to supply power to the power generation device 22 for a specified period after the start of sediment discharge (after opening the sediment discharge gate 26) to convert electrical energy into kinetic energy of the discharged sediment flow S1. In other words, in the power generation method using dam sediment in this embodiment, during the sediment removal process, power is supplied to the power generation device body 31 or power generation device 41 (not shown) for a specified period after the start of sediment removal to drive the generator body and rotate the impeller devices 30 and 45. Here, the specified period mentioned above may be, for example, the period until the flow velocity of the sediment flow S1 in the sediment removal channel 21 exceeds a specified value, as will be described later.

[0089] As the sediment discharge flow S1 flows through the sediment discharge channel 21, it begins to be discharged into the downstream area R2 of the dam, as shown in Figure 10C. When the sediment discharge flow S1 begins to be discharged into the downstream area R2 of the dam, the siphon principle comes into play due to the difference in height between the upstream end of the sediment discharge pipe 21a and the downstream end of the sediment discharge channel 21c. Even if there are places in the path of the sediment discharge channel 21 that are higher than the upstream end of the sediment discharge pipe 21a, the sediment discharge flow S1 will continue to flow through the sediment discharge channel 21.

[0090] In the sand removal process of this embodiment, if the flow velocity of the sand removal flow S1 in the sand removal channel 21 exceeds a specified value, the supply of external power to the power generation device body is stopped, and power generation is started by the rotation of the impeller devices 30 and 45. For this purpose, it is advisable to measure the flow velocity of the sand removal flow S1 in the sand removal channel 21 using a flow meter or the like. In other words, in the sand removal process in this embodiment, after the start of sand removal, if the flow velocity of the sand removal flow S1 in the sand removal channel 21 is below a specified value, power is supplied to the power generation device 22 to convert electrical energy into kinetic energy of the sand removal flow S1. If the flow velocity of the sand removal flow S1 in the sand removal channel 21 exceeds a specified value, the power supply to the power generation device 22 is stopped, and the power generation device 22 converts the kinetic energy of the sand removal flow into electrical energy (starts the power generation process). Specifically, in the sand removal process in this embodiment, after the start of sand removal, if the flow velocity of the sand removal flow S1 in the sand removal channel 21 is below a specified value, power may be supplied to the main body of the power generator to drive the generator body and rotate the impeller devices 30 and 45. If the flow velocity of the sand removal flow S1 in the sand removal channel 21 exceeds the specified value, the power supply to the main body of the power generator may be stopped, and a power generation process may be carried out in which the kinetic energy of the sand removal flow S1 is converted into electrical energy by the power generator 22.

[0091] In the power generation method using dam sediment in this embodiment, the switching operation to stop the supply of external power to the power generation device and start power generation by the power generation device may be performed manually by an operator, or it may be performed automatically based on the measurement results of the flow meter as described above.

[0092] In addition, a separate electric motor may be provided in addition to the main power generation device, so that the impeller devices 30 and 45 can be rotated by the electric motor.

[0093] Furthermore, the electricity generated by the power generation system 20 and power generation method using dam sediment in this embodiment may be transmitted in the same way as the hydroelectric power generation equipment 2, or, for example, if a sediment discharge pipe is laid to span the crest 7c of the dam, and electric equipment such as a pump (vacuum pump, etc.) is installed to transport the sediment S in the sediment discharge pipe, it may be used as the power to drive the electric equipment as appropriate within the dam facility.

[0094] Therefore, according to the power generation system 20 using dam sediment and the power generation method using dam sediment of this embodiment, it becomes possible to generate electricity by effectively utilizing the kinetic energy (potential energy of sediment S) during the discharge of sediment S, which would otherwise be wasted by simply being discharged into the downstream area R2 of the dam, just as in the first embodiment.

[0095] Furthermore, in the power generation system 20 using dam sediment and power generation using dam sediment of this embodiment, even when using sediment S with low potential energy, it is possible to secure kinetic energy equivalent to that of hydroelectric power generation and to secure power generation efficiency equivalent to that of hydroelectric power generation.

[0096] Furthermore, it is possible to use hydroelectric power generation and power generation using dam sediment in combination, thereby increasing the value of dam 1 for hydroelectric power generation.

[0097] Furthermore, in the power generation system 20 using dam sediment and power generation using dam sediment of this embodiment, the power generation devices 22 and 41 include impeller devices 30 and 45 that receive the discharged sediment flow S1 and rotate around the axis O1, and a power generation device body (31) that generates electricity by the rotation of the impeller devices 30 and 45. Using power generation devices 22 and 41 similar to those in hydroelectric power generation facility 2, it becomes possible to perform sediment-based power generation.

[0098] Furthermore, a crusher 40 may be used as the power generation device 22, or a configuration similar to that of the crusher 40 may be adopted. This eliminates the need to research and develop a new power generation device 22 with sufficient durability against the sediment discharge flow S1 from scratch. Furthermore, when discharging the accumulated sediment S, it becomes possible to repurpose the crusher 40 of the pre-installed crushing equipment, or to prepare a new power generation device with specifications approximately the same as the crusher 40, thereby converting the kinetic energy of the sediment discharge flow S1 into electrical energy to generate electricity.

[0099] Furthermore, in this embodiment, since the power generation device 22 of the power generation system 20 using dam sediment is located downstream of the dam body 7, it can be added to an existing dam 1 relatively easily compared to the power generation systems 20 according to the fourth and fifth embodiments described later. That is, for example, when installing the power generation system 20 using dam sediment of this embodiment in an existing dam 1, the amount of modification required to the existing dam 1 is relatively small, such as installing a sediment discharge channel 21 in the existing dam body 7. Therefore, it becomes relatively easy to install the power generation system using dam sediment of this embodiment in an existing dam 1.

[0100] Furthermore, it is possible to achieve the same effects and advantages as in the first embodiment. For example, in the power generation method using dam sediment of this embodiment, the sediment S is loosened in advance, and the sediment is removed using the water pressure and scavenging force of the water W stored in the reservoir 5. Therefore, it is possible to eliminate the two conventional dam operation processes of (b) lowering the water level of the reservoir 5 and (d) restoring the water level of the reservoir 5, which require a great deal of time and effort for observation and management. Thus, it becomes possible to remove sediment efficiently and effectively, and to generate electricity with the removed sediment flow S1. In other words, it becomes possible to achieve even more remarkable effects.

[0101] Furthermore, by loosening the accumulated sediment S beforehand, the range of influence of the scouring force on the sediment S, and consequently the range from which sediment can be removed, can be greatly expanded. Therefore, by simply taking the extra step of loosening the accumulated sediment S beforehand, it is possible to significantly improve the sediment removal efficiency and, consequently, the power generation efficiency.

[0102] (Third embodiment) The following description will refer to Figures 11 and 12 to explain the power generation system and power generation method using dam sediment according to the third embodiment. In this embodiment, some of the configurations of the sediment removal equipment 4 differ from those of the second embodiment. Therefore, the same reference numerals are used for components similar to those in the second embodiment, and detailed explanations are omitted. Figure 11 is a schematic diagram showing an example of a power generation system using dam sediment according to the third embodiment. Figure 12 is a schematic diagram showing the cross-section in the direction of arrow AA in Figure 11.

[0103] (Power generation system using dam sediment) The sediment removal equipment 4 of this embodiment, like the first and second embodiments, includes a power generation system 20 that uses sediment S accumulated at the bottom 6 of the dam reservoir 5 to generate electricity.

[0104] Furthermore, the power generation system 20 using dam sediment in this embodiment, as in the second embodiment, is configured as shown in Figure 11, to include a sediment discharge channel 21 for discharging the sediment S accumulated on the bottom 6 of the dam reservoir 5 as a sediment discharge flow S1 to the downstream side R2 of the dam body 7, and a power generation device 22 provided in the sediment discharge channel 21 for converting the kinetic energy of the sediment discharge flow S1 into electrical energy.

[0105] The sediment discharge channel 21 in this embodiment, like the second embodiment, is provided on the lower side of the dam body 7, for example, penetrating from the back surface 7b to the front surface 7a of the dam body 7, and includes a sediment discharge pipe (sediment discharge outlet) 21a for sending sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam, and the outlet 21b of this sediment discharge pipe 21a is connected to the flow path 61 of the power generation device 22, which will be described later.

[0106] Furthermore, the sediment discharge pipe 21a for sending the sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam does not need to be limited to a sediment discharge pipe that penetrates the dam body 7, as in the second embodiment. It is sufficient if it is possible to send the sediment S from the upstream area R1 of the dam to the downstream area R2 of the dam, and further to the power generation device 22 of this embodiment. For example, it may be a sediment discharge pipe that extends to the downstream area R2 of the dam by straddling the crest 7c of the dam body 7, a sediment discharge pipe that extends to the downstream area R2 of the dam by bypassing the dam body 7, or a sediment discharge pipe that extends to the downstream area R2 of the dam through the ground G below the dam body 7. In addition, the sediment discharge pipe may be laid to send the dredged sediment S to the power generation device 22 of this embodiment. Furthermore, these sediment discharge pipes may be provided selectively as appropriate.

[0107] The power generation device 22 of this embodiment is configured to include a converter 50 that includes an endless belt 52 that travels in response to the sand discharge flow S1 and a rotating body 53 that rotates due to the movement of the endless belt 52, and a power generation device body 51 that generates electricity by the rotation of the rotating body 53 in the converter 50. The power generation device body 51 can be a generator that generates electricity by the rotation of the rotating body 53, similar to the generator 12 of the hydroelectric power generation facility 2. In addition, in the power generation device 22 of this embodiment, a speed increaser (not shown) may be used to rotate the power generation device body 51 at a rotational speed greater than the rotational speed of the rotating body 53.

[0108] The structure of the power generation device 22 of this embodiment will be described further below. As shown in Figures 12 and 13, in the power generation device 22 of this embodiment, the converter 50 and the power generation device body 51 are arranged inside, for example, a concrete structure 60. A flow path 61 for circulating the sediment discharge flow S1 is formed inside the structure 60. In other words, the sediment discharge channel 21 of this embodiment includes the flow path 61 inside the structure 60.

[0109] The flow path 61 in this embodiment may be provided so as to be horizontal from the upstream side to the downstream side (from left to right in the illustration in Figure 11), or it may be provided so as to be inclined so that its height decreases from the upstream side to the downstream side. The same applies to the power generation device 22 in the second embodiment described above, and in the structure in which the impeller device 30 and power generation device 41 in the second embodiment are arranged, the flow path for circulating the sediment discharge flow S1 may be provided so as to be inclined.

[0110] The conversion device 50 in this embodiment is installed in the flow path 61 and is a device for converting the kinetic energy of the sand discharge flow S1 into the kinetic energy of the rotating body 53, and has a structure that mimics, for example, a belt conveyor. That is, in the power generation device 22 of this embodiment, the conversion device 50 has, as the rotating body 53, two pulleys 53A arranged spaced apart along the direction of the sand discharge flow S1, and as the endless belt body 52, a belt 52A wrapped around these two pulleys 53A.

[0111] In the conversion device 50 of this embodiment, multiple crossbars 54 are provided at intervals along the longitudinal direction of the belt 52A, with the crossbars 54 erected on the surface of the belt 52A and extending in the width direction of the belt 52A.

[0112] In this embodiment, the conversion device 50 is positioned above the flow path 61, but it may also be positioned below or to the side of the flow path 61. Positioning the conversion device 50 above the flow path 61 makes it easier to prevent leakage of the sediment discharge flow S1 towards the conversion device 50.

[0113] In the conversion device 50 of this embodiment, among the multiple crossbars 54, the crossbars 54 on the belt 52A that are located below the two pulleys 53A are immersed in the sediment discharge flow S1 in the flow path 61. Therefore, when the sediment discharge flow S1 flows downstream in the flow path 61, it presses the crossbars 54 that are immersed in the sediment discharge flow S1 downstream. As a result, the belt 52A located below the two pulleys 53A travels downstream, rotating the two pulleys 53A and, consequently, the power generation device body 51.

[0114] In this embodiment, the converter 50 is configured to receive force from the sediment discharge flow S1 in the flow path 61 by a plurality of crossbars 54 extending in the width direction and thickness direction of the belt 52A. Therefore, compared to the impeller device 30 and power generator 41 in the second embodiment described above, the surface area that receives force from the sediment discharge flow S1 can be increased, and the load on the converter 50 can be reduced. In the conversion device 50 of this embodiment, each of the multiple horizontal bars 54 may be a plate-shaped member, or it may have a shape that can hold the accumulated sand S and water W in the sand discharge flow S1, for example, like a bucket in a bucket elevator. Furthermore, in the conversion device 50 of this embodiment, the endless band 52 is not limited to a belt 52A, but may be a chain or the like. If the endless band 52 is a chain, the rotating body 53 should be a sprocket that can mesh with the chain.

[0115] (Power generation method using dam sediment) Furthermore, when generating electricity using the dam sediment power generation system 20 of this embodiment and the kinetic energy of the sediment discharge flow S1 (in the power generation method using dam sediment of this embodiment), as in the first and second embodiments, the sediment S accumulated on the bottom 6 of the dam reservoir 5 is first loosened at the bottom 6 (sediment stirring process: see Figure 5).

[0116] Then, the sediment discharge gate 26 is opened, and the water pressure W of the water stored in the reservoir 5 and the scavenging force of the water flow that carries sediment are used to discharge the sediment S loosened in the sediment agitation process, along with the stored water W, as a sediment discharge flow S1 through the sediment discharge pipe 21a (sediment discharge process). The sediment discharge flow S1 sent from the sediment discharge pipe 21a is received by the generator body (generator) of the power generation device 22, and the kinetic energy of this sediment discharge flow S1 is used to rotate the converter 50 to generate electricity, and the sediment discharge flow S1 is discharged into the downstream area R2 of the dam (power generation process: see Figure 6).

[0117] Here, for example, the power generation device body 51 is configured such that it can function as an electric motor by supplying power to the power generation device body 51 from an external source. Then, in the sand removal process, the belt 52A is driven by supplying power to the power generation device body 51 from an external source. Alternatively, an electric motor may be provided separately from the power generation device body 51, and the belt 52A may be driven by this electric motor. This makes it easier for the sediment discharge flow S1 to circulate within the channel 61. In other words, in the power generation system using dam sediment according to the third embodiment, similar to the power generation system using dam sediment according to the second embodiment, the power generation device 22 is preferably configured to convert electrical energy into kinetic energy of the sediment discharge flow S1 by receiving a power supply. The following describes how, in the sand removal process, the power generation device body 51 is driven by supplying power from an external source.

[0118] In the sediment removal process in this embodiment, when the sediment removal gate 26 is opened, the water pressure of the water W stored in the reservoir 5 and the scavenging force of the water W carrying sediment and other materials cause the sediment S loosened in the sediment agitation process to begin flowing through the sediment removal channel 21 (sediment removal pipe 21a) as sediment removal flow S1 together with the stored water W, reaching the conversion device 50, and then flowing further downstream through the sediment removal channel 21 (flow channel 61). Furthermore, in the sand removal process in this embodiment, the supply of external power to the power generation device body 51 is started at approximately the same time as the opening of the sand removal gate 26. As a result, the power generation device body 51 is driven by the external power to rotate the pulley 53A and drive the belt 52A. Therefore, even if the flow velocity of the sand removal flow S1 is relatively low in the initial stage of the sand removal process, kinetic energy is imparted to the sand removal flow S1 by the movement of the belt 52A, making it easier for the sand removal flow S1 to flow within the sand removal channel 21. Furthermore, in order to prevent the crossbar 54 from obstructing the flow of the sediment discharge flow S1, the timing for starting the operation of the power generation device body 51 by external power should be before the sediment discharge flow S1 reaches the converter 50.

[0119] Thus, in the power generation system using dam sediment according to the third embodiment, the power generation device body 51 is preferably configured to move along the belt 52A when it receives a power supply. Furthermore, in the power generation method using dam sediment in this embodiment, during the sediment discharge process, it is preferable to supply power to the power generation device 22 for a specified period after the start of sediment discharge (after opening the sediment discharge gate 26) to convert electrical energy into kinetic energy of the discharged sediment flow S1. In other words, in the power generation method using dam sediment in this embodiment, during the sediment removal process, power is supplied to the power generation device body 51 for a specified period after the start of sediment removal to drive the power generation device body 51, thereby rotating the pulley 53A and driving the belt 52A. Here, the specified period mentioned above may be, for example, the period until the flow velocity of the sediment flow S1 in the sediment removal channel 21 exceeds a specified value, as will be described later.

[0120] As the sediment discharge flow S1 circulates within the sediment discharge channel 21, it begins to be discharged into the downstream area R2 of the dam.

[0121] In the sand removal process of this embodiment, if the flow velocity of the sand removal flow S1 in the sand removal channel 21 exceeds a specified value, the supply of external power to the power generation device body 51 is stopped, and power generation is started by the movement of the belt 52A, i.e., the rotation of the pulley 53A. For this purpose, it is advisable to measure the flow velocity of the sand removal flow S1 in the sand removal channel 21 using a flow meter or the like. In other words, in the sand removal process in this embodiment, after the start of sand removal, if the flow velocity of the sand removal flow S1 in the sand removal channel 21 is below a specified value, power is supplied to the power generation device 22 to convert electrical energy into kinetic energy of the sand removal flow S1. If the flow velocity of the sand removal flow S1 in the sand removal channel 21 exceeds a specified value, the power supply to the power generation device 22 is stopped, and the power generation device 22 converts the kinetic energy of the sand removal flow into electrical energy (starts the power generation process). Specifically, in the sand removal process in this embodiment, after the start of sand removal, if the flow velocity of the sand removal flow S1 in the sand removal channel 21 is below a specified value, power is supplied to the power generation device body 51 to drive the power generation device body 51 and rotate the pulley 53A. If the flow velocity of the sand removal flow S1 in the sand removal channel 21 exceeds the specified value, the power supply to the power generation device body 51 is stopped, and a power generation process is carried out in which the kinetic energy of the sand removal flow S1 is converted into electrical energy by the power generation device 22.

[0122] In the power generation method using dam sediment in this embodiment, the switching operation to stop the supply of external power to the power generation device body 51 and start power generation by the power generation device body 51 may be performed manually by an operator, or it may be set up to switch automatically based on the measurement results of the flow meter as described above.

[0123] In addition, a motor may be provided separately from the main power generation device 51, so that at least one of the two pulleys 53A on the upstream and downstream sides can be rotated by the motor.

[0124] Furthermore, the electricity generated by the power generation system 20 and power generation method using dam sediment in this embodiment may be transmitted in the same way as the hydroelectric power generation equipment 2, or, for example, if a sediment discharge pipe is laid to span the crest 7c of the dam, and electric equipment such as a pump (vacuum pump, etc.) is installed to transport the sediment S in the sediment discharge pipe, it may be used as the power to drive the electric equipment as appropriate within the dam facility.

[0125] Therefore, according to the power generation system 20 using dam sediment and the power generation method using dam sediment of this embodiment, it becomes possible to generate electricity by effectively utilizing the kinetic energy (potential energy of sediment S) during the discharge of sediment S, which would otherwise be wasted by simply being discharged into the downstream area R2 of the dam, just as in the first and second embodiments.

[0126] Furthermore, in the power generation system 20 using dam sediment and power generation using dam sediment of this embodiment, even when using sediment S with low potential energy, it is possible to secure kinetic energy equivalent to that of hydroelectric power generation and to secure power generation efficiency equivalent to that of hydroelectric power generation.

[0127] Furthermore, it is possible to use hydroelectric power generation and power generation using dam sediment in combination, thereby increasing the value of dam 1 for hydroelectric power generation.

[0128] Furthermore, in the power generation system 20 using dam sediment and power generation using dam sediment of this embodiment, the power generation device 22 comprises an endless belt 52 that travels in response to the discharged sediment flow S1, a rotating body 53 that rotates due to the movement of the endless belt 52, and a power generation device body 51 that generates electricity through the rotation of the rotating body 53. This allows the kinetic energy of the sand discharge flow S1 to drive the endless belt 52, which in turn rotates the rotating body 53. The rotational energy of the rotating body 53 is then converted into electrical energy by the power generation device body 51 to generate electricity.

[0129] Furthermore, in the power generation system 20 using dam sediment of this embodiment, the power generation device 22 is located downstream of the dam body 7. Therefore, compared to the power generation systems 20 according to the fourth and fifth embodiments described later, it is relatively easy to add the power generation system 20 using dam sediment to an existing dam 1. That is, for example, if the power generation system 20 using dam sediment of this embodiment is installed in an existing dam 1, the modifications to the existing dam 1 are relatively minimal, such as installing a sediment discharge channel 21 in the existing dam body 7. For this reason, it is relatively easy to install the power generation system using dam sediment of this embodiment in an existing dam 1.

[0130] Furthermore, it is possible to achieve the same effects and advantages as in the first and second embodiments. For example, in the power generation method using dam sediment of this embodiment, the sediment S is loosened in advance, and the sediment is removed using the water pressure and scavenging force of the water W stored in the reservoir 5. Therefore, it is possible to eliminate the two conventional dam operation processes of (b) lowering the water level of the reservoir 5 and (d) restoring the water level of the reservoir 5, which require a great deal of time and effort for observation and management. Thus, it becomes possible to remove sediment efficiently and effectively, and to generate electricity with the removed sediment flow S1. In other words, it becomes possible to achieve even more remarkable effects.

[0131] Furthermore, by loosening the accumulated sediment S beforehand, the range of influence of the scouring force on the sediment S, and consequently the range from which sediment can be removed, can be greatly expanded. Therefore, by simply taking the extra step of loosening the accumulated sediment S beforehand, it is possible to significantly improve the sediment removal efficiency and, consequently, the power generation efficiency.

[0132] (Fourth Embodiment) The following description will refer to Figure 13 and explain the power generation system and power generation method using dam sediment according to the fourth embodiment. In this embodiment, some of the configurations of the sediment removal equipment 4 differ from those of the second embodiment. Specifically, this embodiment differs from the power generation system 20 of the second embodiment in that the power generation device 22 according to the second embodiment is located inside the dam body 7. Therefore, the same reference numerals are used for components similar to those in the second embodiment, and detailed explanations are omitted. Figure 13 is a schematic diagram showing an example of a power generation system using dam sediment according to the fourth embodiment.

[0133] (Power generation system using dam sediment) The sediment removal equipment 4 of this embodiment, like the first to third embodiments, includes a power generation system 20 using dam sediment for generating electricity using the sediment S accumulated at the bottom 6 of the dam reservoir 5.

[0134] Furthermore, the power generation system 20 using dam sediment in this embodiment, as in the second embodiment, is configured as shown in Figure 13, to include a sediment discharge channel 21 for discharging the sediment S accumulated on the bottom 6 of the dam reservoir 5 as a sediment discharge flow S1 to the downstream side R2 of the dam body 7, and a power generation device 22 provided in the sediment discharge channel 21 for converting the kinetic energy of the sediment discharge flow S1 into electrical energy.

[0135] The power generation device 22 of this embodiment is located inside the dam body 7. Specifically, the power generation device 22 of this embodiment includes an impeller device 30 having an impeller 30a that rotates around its axis in response to the sediment discharge flow S1, and a power generation device body 31 that generates electricity by the rotation of the impeller device 30, both located inside the dam body 7. In this embodiment, a power generation device 41 that repurposes a crusher 40 from a crushing facility similar to that of the second embodiment, or a power generation device 41 with specifications substantially equivalent to those of the crusher 40, may also be located inside the dam body 7.

[0136] (Power generation method using dam sediment) In the power generation method using the dam sediment power generation system 20 of this embodiment, power can be generated by performing a sediment agitation step (see Figure 5) and a power generation step (see Figure 6), similar to the first to third embodiments.

[0137] In the power generation system 20 using dam sediment of this embodiment, the power generation device 22 is located inside the dam body 7, making it relatively easy to secure space for the installation of the power generation device 22. Furthermore, in the power generation system 20 using dam sediment of this embodiment, the power generation device 22 can be placed inside the dam body 7 relatively easily when the dam 1 is newly constructed.

[0138] (Fifth embodiment) The power generation system and power generation method using dam sediment according to the fifth embodiment will be described below with reference to Figure 14. In this embodiment, some of the configurations of the sediment removal equipment 4 differ from those of the third embodiment. Specifically, this embodiment differs from the power generation system 20 of the third embodiment in that the power generation device 22 according to the third embodiment is located inside the dam body 7. Therefore, the same reference numerals are used for components similar to those in the third embodiment, and detailed explanations are omitted. Figure 14 is a schematic diagram showing an example of a power generation system using dam sediment according to the fifth embodiment.

[0139] (Power generation system using dam sediment) The sediment removal equipment 4 of this embodiment, like the first to fourth embodiments, includes a power generation system 20 using dam sediment for generating electricity using the sediment S accumulated at the bottom 6 of the dam reservoir 5.

[0140] Furthermore, the power generation system 20 using dam sediment in this embodiment, as in the third embodiment, is configured as shown in Figure 13, to include a sediment discharge channel 21 for discharging the sediment S accumulated on the bottom 6 of the dam reservoir 5 as a sediment discharge flow S1 to the downstream side R2 of the dam body 7, and a power generation device 22 provided in the sediment discharge channel 21 for converting the kinetic energy of the sediment discharge flow S1 into electrical energy.

[0141] The power generation device 22 of this embodiment is located inside the dam body 7. Specifically, the power generation device 22 of this embodiment includes a converter 50 which includes an endless belt 52 that travels in response to the sediment discharge flow S1 and a rotating body 53 that rotates due to the movement of the endless belt 52, and a power generation device body 51 which generates electricity by the rotation of the rotating body 53 in the converter 50, all located inside the dam body 7. In the power generation device 22 of this embodiment, as shown in Figure 14, the converter 50 is arranged so that the belt 52A runs along the sediment removal channel 21 that penetrates from the back surface 7b to the front surface 7a of the dam body 7. Although not shown, if a part of the sediment removal channel 21 extends within the dam body 7, for example in the depth direction of the paper in Figure 14, the converter 50 may be arranged so that the belt 52A runs along the depth direction of the paper in Figure 14.

[0142] (Power generation method using dam sediment) In the power generation method using the dam sediment power generation system 20 of this embodiment, power can be generated by performing a sediment stirring step (see Figure 5) and a power generation step (see Figure 6), similar to the first to fourth embodiments.

[0143] In the power generation system 20 using dam sediment of this embodiment, the power generation device 22 is located inside the dam body 7, making it relatively easy to secure space for the power generation device 22. In other words, the power generation device 22 can be installed without having to secure space for it in the downstream area R2 of the dam. Furthermore, in the power generation system 20 using dam sediment of this embodiment, if the dam 1 is newly constructed, it is relatively easy to place the power generation device 22 inside the dam body 7.

[0144] Figure 15 schematically shows a modified example of the power generation system using dam sediment according to the fifth embodiment. As shown in Figure 15, a portion of the power generation device 22 in this embodiment may protrude downstream from the front surface 7a of the dam body 7. In other words, at least a portion of the power generation device 22 in this embodiment may be located inside the dam body 7. Although not shown in the figures, a portion of the power generation device 22 according to the fourth embodiment may protrude downstream from the front surface 7a of the dam body 7. Since at least a portion of the power generation device 22 is located inside the dam body 7, it becomes relatively easy to secure space for the installation of the power generation device 22.

[0145] Although several embodiments of the power generation system and power generation method using dam sediment described herein have been explained above, the invention is not limited to the above embodiments and can be modified as appropriate without departing from its spirit.

[0146] For example, in each embodiment, the dam described herein is assumed to be a multi-purpose dam, but it does not necessarily have to be a multi-purpose dam. In other words, the dam according to this disclosure is a dam 1 that includes a dam body 7, is capable of storing water W in the upstream area R1 of the dam by the dam body 7, and generates sediment S at the bottom 6 as a result of water storage, and requires the discharge of this sediment S, and is equipped with a power generation system 20 (sediment removal equipment 4) using dam sediment of the above-described embodiments, there is no need to limit other configurations in particular to the above-described embodiments.

[0147] Furthermore, of course, the configurations and modifications of each embodiment may be combined.

[0148] Furthermore, in each embodiment, the sediment S accumulated on the bottom 6 of the reservoir 5 is loosened in a sediment stirring process and then discharged as a discharged sediment flow S1 through a discharge channel and discharge pipe. However, if the sediment S can be discharged without using the sediment stirring process, the sediment stirring process does not necessarily have to be performed. For example, if the sediment removal efficiency and, consequently, the power generation efficiency can be suitably ensured by providing equipment to control the area where the sediment S is generated, changing the position of the intake port of the discharge pipe that sucks in the sediment S, or providing multiple intake ports, the sediment stirring process does not have to be performed.

[0149] Furthermore, it is perfectly acceptable to install the sediment discharge channels, sediment removal channels, sediment discharge pipes, and even the power generation equipment in locations where a large drop in the sediment discharge flow S1 can be achieved, or to extend them to locations where a large drop in the sediment discharge flow S1 can be achieved. [Explanation of Symbols]

[0150] 1 dam 2. Hydroelectric power generation facilities 3. Water discharge equipment 4 Sand removal equipment 5 Dam Reservoirs 6 Underwater 7 Embankment body 7a front 7b Back 7c Embankment top 13 Transformer 14 Power transmission equipment 15 Spillway 20. Power generation system using dam sediment 21 Sand drainage path 21a Sand discharge pipe (sand discharge pipe) 21b Outlet 21c Sand road 21d Direction wall 22 Power generation equipment 23. Vibration power generation device 24 Impact-generating plate 30 Impeller device 30a Impeller 31 Power generation unit 40 Crusher 41 Power generation equipment 42 Outlet 43 Inlet 44 Housing 45 Impeller device 46 Impeller 47 Rotation axis 50 Conversion device 51 Power generation unit 52 Endless band 52A belt 53. Solids of revolution 53A Pulley 54 horizontal bars 61 Flow channels G Ground R1 Upstream side of the dam R2 Dam downstream side S Sediment S1 Sand flow W Water (Water Storage)

Claims

1. A power generation system for generating electricity using sediment accumulated at the bottom of a sea, A sediment discharge channel for transporting the sediment accumulated on the seabed as a sediment discharge flow to the opposite side of the seabed, across the dam body, The system includes a power generation device installed in the aforementioned sediment discharge channel, which converts the kinetic energy of the sediment discharge flow into electrical energy, The aforementioned sediment discharge channel includes at least one of the following: a first sediment discharge pipe penetrating the dam body; a second sediment discharge pipe extending to the opposite side by bypassing the dam body and not straddling the dam crest; or a third sediment discharge pipe extending to the opposite side through the ground below the dam body. Power generation system.

2. The aforementioned power generation device is Includes an impact power generation plate for causing the aforementioned sand discharge flow to collide and converting the impact energy into power generation energy, The power generation system according to claim 1.

3. A power generation system for generating electricity using sediment accumulated at the bottom of a sea, A sediment discharge channel for transporting the sediment accumulated on the seabed as a sediment discharge flow to the opposite side of the seabed, across the dam body, The system includes a power generation device installed in the aforementioned sediment discharge channel, which converts the kinetic energy of the sediment discharge flow into electrical energy, The power generation device includes an impact power generation plate for causing the sand discharge flow to collide and converting the impact energy into power generation energy. The aforementioned sand discharge channel is A sediment discharge pipe that penetrates the aforementioned dam body, The dam body includes a guide wall provided on the front surface of the dam body, which forms a sediment discharge channel that guides the sediment discharged from the discharge port of the sediment discharge pipe to the opposite side, The impact generating plate is attached to at least a portion of the wall surface of the flow guide wall. Power generation system.

4. A power generation system for generating electricity using sediment accumulated at the bottom of a sea, A sediment discharge channel for transporting the sediment accumulated on the seabed as a sediment discharge flow to the opposite side of the seabed, across the dam body, The system includes a power generation device installed in the aforementioned sediment discharge channel, which converts the kinetic energy of the sediment discharge flow into electrical energy. The aforementioned power generation device is An impeller device that rotates around its axis in response to the aforementioned sand discharge flow, The system comprises a power generation device body that generates electricity by the rotation of the impeller device, The aforementioned power generation device can be used as a crusher, The aforementioned crusher is configured such that the direction of rotation of the rotating shaft is different during power generation and during crushing. Power generation system.

5. At least a portion of the power generation equipment is located inside the dam body. The power generation system according to claim 4.

6. A method for generating electricity using a power generation system described in any one of claims 1 to 5, A sediment agitation step in which the sediment accumulated on the seabed is loosened on the seabed, A sand removal step is performed in which the sand loosened in the sand agitation step is discharged as a sand discharge flow through the sand discharge channel together with the stored water, The system includes a power generation step, which converts the kinetic energy of the sediment discharge flow into electrical energy using the power generation device. Method of generating electricity.

7. In the aforementioned sediment removal process, during the first period, the power generation device converts the electrical energy of external power into the kinetic energy of the sediment removal flow, and after the elapsed time of the first period, the supply of external power to the power generation device is stopped. The power generation process is carried out after the first period in the sand removal process has elapsed. The power generation method according to claim 6.

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