JP2023038547A - Power generating system - Google Patents

Abstract

To provide a power generating system allowing hydraulic power generation through circulation of underground water without using a siphon pipe.SOLUTION: A power generation system 100 comprises: a production well 110 fluidly connected with a position 112 of a large amount of underground water W where a relatively large amount of the underground water W is stored in a pressured layer; a returning well 120 fluidly connected to a position 122 where a relatively small amount of the ground water W exists; a water passage 130 guiding at least a part of the underground water W from the production well 110 to the returning well 120; and a power generator 150 generating electric power through receiving kinetic energy of the underground water W. The underground water W supplied to the returning well 120 is returned to the position 122 of the large amount of the underground water W by pumping up the underground water from the production well 110 to lower a water level at the position 112 of the large amount of the underground water as well as by supplying at least a part of the underground water to the returning well 120 to increase a water level at the position 122 of the small amount of the ground water.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power generation system that produces relatively small-scale hydroelectric power production.

Conventionally, as disclosed in US Pat. A system has been developed in which pipes are used to allow underground water to flow, and this underground water flow is used to generate electricity.

JP 2011-185778 A

However, in the case of a system such as the power generation system disclosed in Patent Document 1, the groundwater of a pumping well is temporarily lifted to a high position with a siphon pipe and then returned to an injection well located at a lower position. If the water level drops and the end of the siphon pipe on the injection well side is exposed from the groundwater and air enters the siphon pipe, the flow of groundwater in the siphon pipe will stop, and power generation will also stop. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and an object of the present invention is to provide a power generation system that generates hydroelectric power by circulating groundwater without using a siphon pipe.

According to one aspect of the invention,
a production well fluidly connected to a groundwater abundance location in the confined formation in which a relatively large amount of groundwater is present;
a reinjection well formed at a position lower in altitude than the production well, which is fluidly connected to a groundwater small amount position in the confined layer where the amount of groundwater is relatively small;
a channel for guiding at least part of the groundwater pumped from the production well to the return well;
A power generation system comprising a generator that is arranged in the waterway and receives the kinetic energy of the groundwater to generate power,
The thickness from the upper end of the confined layer to the ground surface at the low groundwater position where the return well is provided is greater than the thickness from the upper end of the confined layer to the ground surface at the high groundwater position where the production well is provided. and the low groundwater position and the high groundwater position are aligned horizontally, so that the pressure in the stratum at the low groundwater position is higher than the pressure in the stratum at the high groundwater position,
lowering the water level at the high groundwater location to reduce the pressure in the stratum at the high groundwater location by pumping the groundwater from the production well and the low groundwater location by supplying at least a portion of the groundwater to the reinjection well; By raising the water level of the groundwater and increasing the pressure in the stratum at the position of the small amount of groundwater,
The groundwater supplied to the return well is returned to the large amount of groundwater position where the water level is lowered due to the difference between the pressure in the stratum at the large amount of groundwater position and the pressure in the stratum at the small amount of groundwater position. A power generation system is provided.

Preferably,
The production well and the return well are formed on mountain slopes, respectively,
The ground surface position of the return well is set at a position lower in altitude than the ground surface position of the production well.

According to the power generation system according to the present invention, in the confined layer, a boundary layer is formed between a large amount of groundwater position where a relatively large amount of groundwater exists and a small amount of groundwater position where a relatively small amount of groundwater exists. and the thickness from the top of the confined layer to the ground surface at the location of the small amount of groundwater where the reinjection well is established is the distance from the top of the confined layer to the surface of the ground at the location of the large amount of groundwater where the production well is established. It is set so that it is thicker than the thickness, and the low groundwater volume position and the high groundwater volume position are horizontally aligned with each other. As a result, due to the difference in thickness from the upper end of the confined layer to the surface, the pressure at the low groundwater position is higher than the pressure at the high groundwater position, resulting in an equilibrium pressure. The groundwater levels at the large groundwater level and the small groundwater level in the equilibrium pressure state are referred to as respective equilibrium water levels.

In this state, by pumping up groundwater from the production well, the water level at the location of the large amount of groundwater is lowered below the equilibrium water level at the location of the large amount of groundwater, and the pressure at the location of the large amount of groundwater is lowered below the equilibrium pressure (at the location of the large amount of groundwater). , by supplying at least part of the groundwater pumped up from the production well to the reinjection well to raise the water level at the low groundwater position to raise the pressure at the low groundwater position above the equilibrium pressure (at the low groundwater position) The difference between the pressure at the location and the pressure at the low groundwater location and the equilibrium pressure at each location allows the groundwater supplied to the reinjection well to be returned to the high groundwater location via the boundary layer. It is possible to cause the groundwater to circulate to and from the low volume position.

The term "water level" here means "groundwater level", and "groundwater level" means "underground pressure received by the confined aquifer".

As a result, hydroelectric power can be generated by circulating groundwater without using a siphon pipe.

In addition, unlike hydroelectric power generation, which simply discharges water from high-lying reservoirs and dams into low-lying rivers and seas to generate power, groundwater pumped up from production wells is returned to reinjection wells. It is possible to supply a power generation system that can maintain the water content of the entire mountain or the like on which the power generation system is installed and that does not greatly change the geological strata and the local environment.

It is a figure showing an example of power generation system 100 concerning an embodiment to which the present invention was applied.

(Configuration of power generation system 100)
A power generation system 100 according to an embodiment to which the present invention is applied, as shown in FIG. there is

The production well 110 is a well drilled from a relatively high altitude point on a slope in a mountainous area, etc., and is a location of a large amount of groundwater W in the confined layer of the underground stratum where a relatively large amount of groundwater W is present. 112 is fluidly connected. Note that the production well 110 is a self-flowing well in which the natural water level is confirmed to near the ground.

The return well 120 is a well drilled from a point lower in altitude than the production well 110 on a slope of a mountainous area, etc., and the amount of groundwater W in the confined layer of the underground stratum is relatively small. It is fluidly connected to the groundwater low volume location 122, which is a highly absorbent stratum that absorbs a small amount of externally supplied water.

In other words, the ground surface position 121 of the return well 120 is set at a lower altitude than the ground surface position 111 of the production well 110 . Also, the bottom 123 of the reinjection well 120 is set at a lower elevation than the bottom 113 of the production well 110 .

The waterway 130 guides at least part of the groundwater W pumped up from the production well 110 to the return well 120, and is a depression formed in the ground surface such as a mountainous area where the production well 110 and the return well 120 are provided. It may be a water pipe provided at a predetermined height from the ground surface, or a culvert formed at a position slightly lower than the ground surface.

The generator 140 is arranged in the waterway 130, and is a machine that receives kinetic energy when the groundwater W pumped up from the production well 110 flows toward the return well 120 to generate electricity. machine is in use.

The pump 150 is arranged in the vicinity of the production well 110, and is intended to pump up the groundwater W from the production well 110 and lower the water level of the large amount of groundwater position 112 when starting the power generation system 100 according to the present embodiment. used as After the circulation of the groundwater W from the return well 120 to the production well 110 is established, the operation of the pump 150 is stopped because the operation of pumping up the groundwater W by the pump 150 becomes unnecessary.

In addition, if the motive power of the water pump 150 is electric power, commercial electric power or electric power generated by solar power generation can be used. Of course, it is conceivable to use a pump that uses power such as an internal combustion engine as the water pump 150 in addition to electric power.

(Circulation of Groundwater W from Reinjection Well 120 to Production Well 110)
Next, the circulation mechanism of the groundwater W from the reinjection well 120 to the production well 110 will be explained using FIG.

The basic principle is that, in a confined layer B closed by a pressurized layer (impermeable layer) C, a large amount of groundwater W is present in a relatively large amount of groundwater W, and a large amount of groundwater W is present. A small amount of groundwater position 122 where the amount of groundwater is relatively small is set at an appropriate distance through the boundary layer D (actually, a mountain or the like that satisfies such conditions is searched for by investigation).

Here, the "boundary layer D" is located between the large amount of groundwater position 112 and the small amount of groundwater position 122 as described above. 112 and the small amount of groundwater position 122 are layers having properties such that the equilibrium pressures are different from each other.

For example, in a mountainous area, the thickness from the top of the confined layer B (that is, the position of the pressurized layer C) to the ground surface (that is, the thickness of the unconsolidated layer A) increases from the summit to the foot of the mountain. Therefore, by forming the ground surface position 121 of the return well 120 at a position lower in altitude than the ground surface position 111 of the production well 110, the distance from the upper end of the confined layer B to the ground surface at the groundwater small amount position 122 where the return well 120 is provided is The thickness H1 is thicker than the thickness H2 from the upper end of the confined layer B to the ground surface at the location 112 where the production well 110 is provided. Of course, as long as the conditions for the thickness from the upper end of the pressure layer to the ground surface are met, the area may not be a mountainous area. It is assumed that the confined layer B at the large amount of groundwater position 112 and the confined layer B at the small amount of groundwater position 122 are horizontally aligned with each other.

Due to the difference in thickness from the upper end of the confined layer B to the ground surface, the pressure at the low groundwater position 122 is higher than the pressure at the high groundwater position 112, and is in equilibrium pressure.

In addition, the water levels of the groundwater W at the large amount of groundwater position and the small amount of groundwater position in the state of this equilibrium pressure are referred to as respective equilibrium water levels.

In such a state, if the water level at the large groundwater position 112 (underground pressure received by the groundwater W at the large groundwater position 112) is lowered below the equilibrium water level at the large groundwater position 112 by pumping the groundwater W from the production well 110, The pressure at the groundwater abundance location 112 in the confined layer B, which is closed by the consolidation layer C, drops below the equilibrium pressure.

At least part of the groundwater W pumped up from the production well 110 is supplied to the reinjection well 120 . As a result, when the water level at the small amount of groundwater position 122 (underground pressure received by the groundwater W at the small amount of groundwater position 122) is raised above the equilibrium water level at the small amount of groundwater position 122, the pressure layer B closed by the pressurized layer C is reached. The pressure at the low groundwater location 122 will rise above the equilibrium pressure.

As a result, due to the difference between the pressure at the large amount of groundwater position 112 and the pressure at the small amount of groundwater position 122 and the equilibrium pressure at each position, the groundwater W supplied to the injection well 120 is released from the small amount of groundwater position 122 in a state where the pressure is higher than the equilibrium pressure. It is returned through the boundary layer D to the groundwater abundance location 112 in a state of less than equilibrium pressure. In this way, it is possible to cause the groundwater W to circulate between the large amount of groundwater position 112 and the small amount of groundwater position 122 .

In the power generation system 100 according to the present embodiment, the thickness from the upper end of the confined layer B (that is, the position of the pressurized layer C) to the ground surface at each position between the high groundwater position 112 and the low groundwater position 122 The difference in equilibrium pressure due to the thickness (i.e., the thickness of the unconfined layer A) and the pumping of the groundwater W at the high groundwater location 112 and the return of the groundwater W at the low groundwater location 122, respectively. Using the pressure difference from the equilibrium pressure (the pressure at the groundwater abundance location 112 is lower than the equilibrium pressure, and the pressure at the groundwater abundance location 122 is higher than the equilibrium pressure), the groundwater abundance location 122 to the groundwater abundance location 112 The point is to create a flow of groundwater W to and circulate the groundwater W.

It should be noted that the amount of groundwater W pumped up from the production well 110 is not returned to 100% of the groundwater W pumped up from the production well 110, but the groundwater W pumped up from the production well 110 using the flow of the groundwater W as described above. 60% to 70% of the water is returned to the reinjection well 120. The groundwater W that remains without being returned to the reinjection well 120 is reinjected underground (for example, to the unpressurized layer A) in the same manner as other surface water.

(Procedure for power generation by power generation system 100)
Next, a procedure for generating power using the power generation system 100 described above will be briefly described. After the production wells 110 and the return wells 120 are first placed in place, the channel 130 is provided between the production wells 110 and the return wells 120 . After that, the generator 140 is arranged in the water channel 130 and the water pump 150 is arranged near the production well 110 to complete the power generation system 100 .

Then, first, the groundwater W is pumped up from the production well 110 by operating the water pump 150 . Then, the water level of the groundwater W at the high-volume groundwater position 112 where the production well 110 is provided begins to drop.

Further, the pumped groundwater W is caused to flow through the waterway 130 , and the kinetic energy of the groundwater W is used to operate the generator 140 to generate power, and at least part of the groundwater W is returned to the return well 120 .

Then, as described above, the water level at the large amount of groundwater position 112 is lowered by pumping up the groundwater W from the production well 110, and at least a portion of the groundwater W is returned to the return well 120 to lower the level of the small amount of groundwater W. As the water level rises, the groundwater W supplied to the return well 120 returns from the low-volume groundwater position 122 to the high-volume groundwater position 112, and the circulation of the groundwater W starts.

When the groundwater W starts to circulate and the pumping operation of the groundwater W by the pump 150 becomes unnecessary, the operation of the pump 150 is stopped.

Thereafter, due to the circulation of the groundwater W, the groundwater W continues to flow through the waterway 130 from the production well 110 to the return well 120, so that power generation by the power generator 140 can be continued.

Thus, according to the power generation system 100 according to this embodiment, hydroelectric power generation can be performed by circulating the groundwater W without using a siphon pipe.

In addition, unlike hydroelectric power generation in which water is simply discharged from a reservoir, dam, or the like in a high position to a river, sea, or the like in a low position to generate power, the groundwater W pumped up from the production well 110 is returned to the return well 120. As a result, the water content of the entire mountain or the like on which the power generation system 100 is installed can be maintained, and the power generation system 100 can be supplied without significantly changing the geological strata or the local environment.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 100... Power generation system 110... Production well, 112... Groundwater large amount position 120... Reduction well, 122... Groundwater small amount position 130... Water channel 140... Generator 150... Lifting pump W... Groundwater, A... Unconfined layer, B... Confined layer , C... Pressure layer, D... Boundary layer

Claims (2)

a production well fluidly connected to a groundwater abundance location in the confined formation in which a relatively large amount of groundwater is present;
a reinjection well formed at a position lower in altitude than the production well, which is fluidly connected to a groundwater small amount position in the confined layer where the amount of groundwater is relatively small;
a channel for guiding at least part of the groundwater pumped from the production well to the return well;
A power generation system comprising a generator that is arranged in the waterway and receives the kinetic energy of the groundwater to generate power,
The thickness from the upper end of the confined layer to the ground surface at the low groundwater position where the return well is provided is greater than the thickness from the upper end of the confined layer to the ground surface at the high groundwater position where the production well is provided. and the low groundwater position and the high groundwater position are aligned horizontally, so that the pressure in the stratum at the low groundwater position is higher than the pressure in the stratum at the high groundwater position,
lowering the water level at the high groundwater location to reduce the pressure in the stratum at the high groundwater location by pumping the groundwater from the production well and the low groundwater location by supplying at least a portion of the groundwater to the reinjection well; By raising the water level of the groundwater and increasing the pressure in the stratum at the position of the small amount of groundwater,
The groundwater supplied to the return well is returned to the large amount of groundwater position where the water level is lowered due to the difference between the pressure in the stratum at the large amount of groundwater position and the pressure in the stratum at the small amount of groundwater position. and power generation system. The production well and the return well are formed on mountain slopes, respectively,
The power generation system according to claim 1, wherein the ground surface position of the return well is set at a position lower in altitude than the ground surface position of the production well.

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