Geothermal power generation system

Abstract

A geothermal power generation system according to one embodiment of the present invention comprises: a gas-liquid separator; a first pipe; a first valve that opens and closes the flow path of the first pipe; a second pipe; an analysis device; a control device that performs control for determining at least one chemical agent from among a plurality of chemical agent candidates on the basis of the result of analysis performed by the analysis device, and for supplying the chemical agent; a chemical agent supply port which is provided to the first pipe and through which the chemical agent is supplied; a third pipe that branches off the second pipe; a chemical agent recovery line that branches off the second pipe and is connected to the second pipe; a waste liquid recovery part, a scale separation part, a first chemical agent recovery part, an impurity separation part, a second chemical agent recovery part, a chemical agent purification part, and a regenerated chemical agent tank, which are provided in midcourse of the chemical agent recovery line sequentially from the upstream side; and a waste liquid adjustment device. The waste liquid adjustment device is connected to the scale separation part, the impurity separation part, and the chemical agent purification part.

Description

Geothermal Power Generation System

[0001] The present invention relates to a geothermal power generation system.

[0002] Geothermal power generation systems extract high-temperature geothermal fluids (geothermal water and geothermal steam) from production wells and generate electricity using the geothermal water or geothermal steam separated from the geothermal fluid. Geothermal fluids extracted from production wells contain more calcium and dissolved silica than well water or river water.

[0003] Dissolved silica in geothermal water collected from production wells is concentrated by reducing pressure in geothermal power generation systems, and is cooled as it flows through the pipes, reducing its solubility. When the silica and dissolved silica contained in the geothermal water become supersaturated, they polymerize to form amorphous silica, which precipitates as scale. The scale adheres to the inner walls of the pipes, potentially causing blockages and other problems, making scale deposition a problem in geothermal power generation systems.

[0004] Conventionally, studies have been conducted on removing scale in geothermal power generation systems by supplying chemicals to piping. For example, Patent Document 1 discloses a geothermal power generation system in which hydrogen peroxide solution is supplied as an oxidizing agent to geothermal water to prevent the buildup of silica scale in the geothermal water system.

[0005] JP 2015-90147 A

[0006] However, in conventional geothermal power generation systems, even after cleaning, scale may remain inside the geothermal power generation system, and there was a problem that the amount of chemicals used for cleaning increased in order to sufficiently remove the remaining scale.

[0007] One aspect of the present invention provides a geothermal power generation system that can sufficiently remove scale and recover the chemicals used for cleaning.

[0008] One aspect of the present invention is a geothermal power generation system including a binary power generation device having a media evaporator, the system comprising: a gas-liquid separator that separates geothermal water from geothermal fluid spouted from a production well; a first pipe that sends the geothermal water separated by the gas-liquid separator to the media evaporator; a first valve that is provided in the first pipe and opens and closes a flow path of the first pipe; a second pipe that sends the geothermal water that has been heat recovered by the binary power generation device from the media evaporator to an injection well; an analyzer that receives the geothermal water flowing through the second pipe and analyzes the components of scale contained in the geothermal water that has flowed in; a control device that determines at least one chemical agent from a plurality of candidate chemical agents based on the analysis results of the analyzer and controls the supply of the chemical agent; a chemical supply port that is provided in the first pipe downstream of the first valve and through which the chemical agent is supplied; a third pipe that branches off from the second pipe; and a chemical recovery line that branches off from the second pipe downstream of the third pipe and is connected to the second pipe. The geothermal power generation system is provided with the following components arranged in the chemical recovery line, from upstream to downstream: a waste liquid recovery section that stores the waste liquid after cleaning the first pipe and the second pipe; a scale separation section that separates the waste liquid into scale-containing matter and primary chemical-containing matter; a first chemical recovery section that stores the primary chemical-containing matter; an impurity separation section that separates the primary chemical-containing matter into primary impurities and secondary chemical-containing matter; a second chemical recovery section that stores the secondary chemical-containing matter; a chemical purification section that purifies the secondary chemical-containing matter and separates it into secondary impurities and regenerated chemical; and a waste liquid adjustment device that supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid stored in the scale separation section, the impurity separation section, and the chemical purification section, wherein the waste liquid adjustment device is connected to the scale separation section, the impurity separation section, and the chemical purification section.

[0009] Another aspect of the present invention is a system comprising: a gas-liquid separator that separates geothermal water and geothermal steam from geothermal fluids ejected from a production well; a power generation device that generates power using the geothermal water or the geothermal steam separated by the gas-liquid separator as a heat source; a retention tank that stores the geothermal water whose heat has been recovered by the power generation device; a return line that connects an outlet of the retention tank to a return well; a return pump that is provided in the return line and returns the geothermal water discharged from the return tank to the return well; an agent injection port that is provided in the return line between the retention tank and the return pump; a first agent addition device that injects an agent into the agent injection port; a branch section that is provided in the return line downstream of the return pump and vertically above the return well and that branches the flow of the geothermal water; and a first liquid analyzer that is connected vertically above the branch section. a scale chip collector connected horizontally to the branching section and having a residue inlet, a dissolving agent inlet, and a residue outlet; a dissolving agent addition device that injects a dissolving agent into the dissolving agent inlet; a control device that switches between injecting the chemical by the first chemical addition device and stopping injection, and switches between injecting the chemical by the dissolving agent addition device and stopping injection, based on the analysis results of the first liquid analyzer; a chemical recovery line that branches off from the pipe connecting the dissolving agent inlet and the dissolving agent addition device, and is connected to the pipe connecting the branching section and the reinjection well; The geothermal power generation system is provided with the following components arranged in the chemical recovery line, from upstream to downstream: a waste liquid recovery section that stores the waste liquid after cleaning the reduction line; a scale separation section that separates the waste liquid into scale-containing matter and primary chemical-containing matter; a first chemical recovery section that stores the primary chemical-containing matter; an impurity separation section that separates the primary chemical-containing matter into primary impurities and secondary chemical-containing matter; a second chemical recovery section that stores the secondary chemical-containing matter; a chemical purification section that purifies the secondary chemical-containing matter and separates it into secondary impurities and regenerated chemicals; and a waste liquid adjustment device that supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid stored in the scale separation section, the impurity separation section, and the chemical purification section, wherein the waste liquid adjustment device is connected to the scale separation section, the impurity separation section, and the chemical purification section.

[0010] Another aspect of the present invention is a system comprising: a gas-liquid separator that separates geothermal water and geothermal steam from geothermal fluids ejected from a production well; a power generation device that generates power using the geothermal water or the geothermal steam separated by the gas-liquid separator as a heat source; a retention tank that stores the geothermal water whose heat has been recovered by the power generation device; a return line that connects an outlet of the retention tank to a return well; a return pump that is provided in the return line and returns the geothermal water discharged from the return tank to the return well; an agent injection port that is provided in the return line between the retention tank and the return pump; a first agent addition device that injects an agent into the agent injection port; a branch section that is provided in the return line downstream of the return pump and vertically above the return well and that branches the flow of the geothermal water; and a first liquid analyzer that is connected vertically above the branch section. a scale chip collector connected horizontally to the branching portion and having a residue inlet, a dissolving agent inlet, and a residue outlet; a dissolving agent addition device that injects a dissolving agent into the dissolving agent inlet; a control device that switches between an injection operation and a stop of injection of the chemical by the first chemical addition device and an injection operation and a stop of injection of the dissolving agent by the dissolving agent addition device based on the analysis results of the first liquid analyzer; a first bypass pipe that branches off from the reduction line downstream of the reduction pump and is connected to the reduction line; a second bypass pipe that branches off from the reduction line downstream of the first bypass pipe and is connected to the reduction line; a first switching valve that is provided midway along the reduction line and can switch the flow path of the reduction line to the first bypass pipe; and a second switching valve that is provided midway along the reduction line and can switch the flow path of the reduction line to the second bypass pipe. a drug preparation unit provided in the first bypass piping, a first gate valve provided in the first bypass piping upstream of the drug preparation unit, and a second gate valve provided in the first bypass piping downstream of the drug preparation unit; a second drug addition device that injects a drug into the drug preparation unit; and an air introduction device that supplies air to the drug in the drug preparation unit.a chemical collection section provided on the second bypass piping, a third gate valve provided on the second bypass piping upstream of the chemical collection section, and a fourth gate valve provided on the second bypass piping downstream of the chemical collection section; a second liquid analyzer connected to the chemical collection section; a chemical recovery line branching off from the second bypass piping and connected to a pipe connecting the branching section to the reinjection well; and a waste liquid recovery section provided in the chemical recovery line, in this order from upstream, for collecting waste liquid after cleaning the reinjection line, a scale separation section for separating the waste liquid into scale-containing matter and primary chemical-containing matter, a first chemical recovery section for collecting the primary chemical-containing matter, an impurity separation section for separating the primary chemical-containing matter into primary impurities and secondary chemical-containing matter, a second chemical recovery section for collecting the secondary chemical-containing matter, a chemical purification section for purifying the secondary chemical-containing matter and separating it into secondary impurities and regenerated chemical, and a regenerated chemical tank for containing the regenerated chemical. a waste liquid adjustment device that supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid contained in the scale separation unit, the impurity separation unit, and the chemical purification unit, wherein the waste liquid adjustment device is connected to the scale separation unit, the impurity separation unit, and the chemical purification unit, and the control device switches between injecting the chemical using the second chemical addition device and stopping the injection, and switches between introducing air using the air introduction device and stopping the introduction, based on the analysis results of the second liquid analyzer, and controls the first switching valve, the second switching valve, and the first to fourth gate valves.

[0011] According to a geothermal power generation system according to one aspect of the present invention, scale can be sufficiently removed and the chemicals used for cleaning can be recovered.

[0012] 1 is a schematic configuration diagram of a geothermal power generation system according to a first embodiment; FIG. 2 is a schematic diagram of a separation vessel; FIG. 3 is a flow diagram for explaining a cleaning method according to the first embodiment; FIG. 4 is a schematic configuration diagram of a chemical recovery line in the geothermal power generation system according to the first embodiment; FIG. 5 is a schematic configuration diagram of a geothermal power generation system according to a second embodiment; FIG. 6 is a time chart showing the cleaning operation in the geothermal power generation system according to the second embodiment; FIG. 7 is a schematic configuration diagram of a geothermal power generation system according to a third embodiment; FIG. 8 is an enlarged view of a main part of FIG. 8 for explaining the cleaning operation in the geothermal power generation system according to the third embodiment; FIG. 9 is an enlarged view of a main part of FIG. 8 for explaining the cleaning operation in the geothermal power generation system according to the third embodiment; FIG. 10 is an enlarged view of a main part of FIG. 8 for explaining the cleaning operation in the geothermal power generation system according to the third embodiment; FIG. 11 is an enlarged view of a main part of FIG. 8 for explaining the cleaning operation in the geothermal power generation system according to the third embodiment;

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0014] First Embodiment A geothermal power generation system 1 according to a first embodiment will be described. First, a configuration for cleaning in the geothermal power generation system 1 will be described.

[0015] Fig. 1 is a schematic diagram of a geothermal power generation system according to a first embodiment, and Fig. 2 is a schematic diagram of a separation vessel. As shown in Fig. 1, the geothermal power generation system 1 includes a binary power generation unit 20 having a medium evaporator 21. The geothermal power generation system 1 also includes a gas-liquid separator 3, a first pipe L1 that sends geothermal water separated in the gas-liquid separator 3 to the medium evaporator 21, a first valve V1 that is provided in the first pipe L1 and that opens and closes the flow path of the first pipe L1, and a second pipe L2 that sends geothermal water that has been heat recovered in the binary power generation unit 20 from the medium evaporator 21 to a reinjection well 4. The geothermal power generation system 1 also includes an analyzer 30, a controller 40, and a chemical supply port 5 that is provided in the first pipe L1 downstream of the first valve and through which a chemical (cleaning agent) is supplied.

[0016] The geothermal power generation system 1 performs binary power generation in a binary power generation device 20 by utilizing the heat of the geothermal water separated in the gas-liquid separator 3. In the geothermal power generation system 1, geothermal fluid collected from the production well 2 is sent to the gas-liquid separator 3. The gas-liquid separator 3 separates the geothermal water from the geothermal fluid spouted from the production well 2. The geothermal water separated in the gas-liquid separator 3 is sent to the medium evaporator 21 via the first pipe L1, where heat exchange is performed to evaporate the low-boiling-point heat medium, and then the geothermal water is returned to the reinjection well 4 via the second pipe L2. When a chemical agent is supplied from the chemical agent supply port 5, the chemical-containing geothermal water (waste liquid after cleaning) flowing through the first pipe L1 and the second pipe L2 is returned to the reinjection well 4 via the chemical agent recovery line L14, which will be described later.

[0017] The heat medium vaporized in the medium evaporator 21 is sent to a turbine 22 via a pipe, and electricity is generated by a generator 23. Furthermore, the heat medium that has passed through the turbine 22 is sent to a medium condenser 24 via a pipe, where it becomes a condensed liquid, and is returned to the medium evaporator 21 via a pipe having a pump 25 provided midway.

[0018] The heat medium used in the binary power generation device 20 is a low-boiling-point heat medium that can be vaporized using the heat of the geothermal water separated in the gas-liquid separator 3. The heat medium is not particularly limited, but examples thereof include normal heptane, isoheptane, normal pentane, isopentane, normal butane, isobutane, hydrofluoroether, 1,1,1,3,3-pentafluoropropane (R245fa), 1,1,1,2-tetrafluoroethane (R134a), chlorodifluoromethane (R22), difluoromethane, a mixture of 1,1,1,2-pentafluoroethane, and 1,1,1,2-tetrafluoroethane (R407c), and the like.

[0019] On the other hand, the geothermal steam separated by the gas-liquid separator 3 may be sent to a turbine (not shown) and electricity may be generated by a generator connected to the turbine. In this case, the gas-liquid separator 3 functions as a flasher that reduces the pressure of the geothermal water to extract geothermal steam. In other words, the geothermal power generation system 1 may include a flash power generation device (not shown) connected to the gas-liquid separator 3 and a binary power generation device 20.

[0020] The geothermal power generation system 1 may include a thirteenth pipe L13 that branches off from the first pipe L1 and connects to the reinjection well 4, and a bypass valve V11 provided midway between the thirteenth pipe L13 and the reinjection well 4.

[0021] The geothermal power generation system 1 may include a second valve V2 provided in the second pipe L2 for opening and closing the flow path of the second pipe L2, a third pipe L3 connected to the second pipe L2 upstream of the second valve V2, and a branching unit 6 capable of branching the flow of geothermal water or chemicals flowing through the third pipe L3 into an analysis line L11 connected to the analysis device 30 and a chemical supply line L12 connected to the chemical supply port 5. The geothermal power generation system 1 may also include a chemical addition device 50 that adds a chemical to the geothermal water flowing through the third pipe L3. Note that FIG. 1 shows a state in which the first valve V1 and the second valve V2 are closed.

[0022] The inner diameter of the analytical line L11 is smaller than the inner diameter of the chemical supply line L12. This allows geothermal water at a flow rate appropriate for analysis, which is smaller than the flow rate of geothermal water flowing into the analytical line L11, to be introduced into the analytical device 30 via the analytical line L11, and allows chemicals at a flow rate necessary for cleaning to be introduced into the chemical supply line L12.

[0023] The geothermal power generation system 1 may include a circulation pump 12 provided in the first pipe L1 downstream of the chemical supply port 5. The circulation pump 12 has a function of sending the geothermal water separated in the gas-liquid separator 3 to the second pipe L2 during normal operation (during power generation), and has a function of circulating the chemical supplied from the chemical supply port 5 together with the geothermal water through a flow path consisting of the first pipe L1, the second pipe L2, the third pipe L3, and the chemical supply line L12 when cleaning is performed after normal operation is stopped (after power generation is stopped).

[0024] Preferably, geothermal power generation system 1 further includes a third valve V3 provided in chemical supply line L12 for opening and closing the flow path of chemical supply line L12. Specifically, chemical supply line L12 includes a first chemical supply line L12a branching from branch portion 6, and a second chemical supply line L12b having one end connected to first chemical supply line L12a and the other end connected to chemical supply port 5. Third valve V3 is provided in first chemical supply line L12a.

[0025] The geothermal power generation system 1 may be provided with a fourth pipe L4, one end of which is connected to the first outlet 34 of the analysis device 30 and the other end of which is connected to the second chemical supply line L12b, for circulating the geothermal water discharged from the analysis device 30.

[0026] The analysis device 30 receives the geothermal water flowing through the second pipe L2 and analyzes the scale components contained in the geothermal water that has flowed in. Examples of scale components contained in the geothermal water include amorphous silica, calcium carbonate, soft mud containing organic matter, and iron rust.

[0027] As shown in Figure 2, the analysis device 30 may have a separation container 31 that separates the geothermal water that flows into the analysis device 30 into solids, liquids, or gases, a gas analyzer 32 that analyzes the gas separated from the separation container 31, and a liquid analyzer 33 that analyzes the liquid separated from the separation container 31.

[0028] The separation vessel 31 may generate a swirling flow therein to separate solids, liquids, or gases contained in the geothermal water. In Figure 2, the flow of solids, liquids, or gases contained in the geothermal water is indicated by arrows. Specifically, the separation vessel 31 may have a cylindrical shape and include a housing 311 arranged so that its axis 310 is at an angle of 0° or more and less than 90° with respect to the vertical direction, a geothermal water inlet 312 provided on the side of the housing 311 through which the geothermal water flows in, and a geothermal water outlet 313 through which the geothermal water is discharged.

[0029] The geothermal water inlet 312 is connected to the analytical line L11, and the geothermal water outlet 313 is connected to the fourth pipe L4. The geothermal power generation system 1 may include a fifth valve V5 provided in the analytical line L11 to open and close the flow path of the analytical line L11, and a sixth valve V6 provided in the fourth pipe L4 to open and close the flow path of the fourth pipe L4.

[0030] The geothermal power generation system 1 may include a flow meter 9 provided in the analysis line L11 to measure the flow rate of the geothermal water flowing into the analysis device 30.

[0031] The interior of the separation container 31 may be divided into three chambers. For example, the separation container 31 may have a first chamber R1, a second chamber R2, and a third chamber R3, which are arranged adjacent to each other in this order from the top in the vertical direction. The first chamber R1, the second chamber R2, and the third chamber R3 are connected at the center. Specifically, the separation container 31 includes two partitions 318 each having an opening 317 at the center, and the partitions 318 may be arranged spaced apart along an axis 310 inside the housing 311. The central axis of the opening 317 coincides with the axis 310 of the housing 311. The partitions 318 may be, for example, a baffle.

[0032] The first chamber R1 is provided on the top surface and has a gas outlet 314 for discharging separated gas. The second chamber R2 is provided on the side surface and has a first solid outlet 315 for discharging separated solids. The third chamber R3 is provided on the bottom surface of the separation vessel 31 and has a second solid outlet 319 for discharging separated solids and a liquid outlet 316 on the side surface and for discharging liquid.

[0033] The solids discharged from the first solid discharge outlet 315 are solids with a relatively large mass, such as rock fragments and iron rust, while the solids discharged from the second solid discharge outlet 319 are solids with a smaller mass than the solids discharged from the first solid discharge outlet 315, such as soft mud and colloids.

[0034] The geothermal water inlet 312 and the geothermal water outlet 313 are provided on the side of the second chamber R2, and the geothermal water inlet 312 is positioned vertically lower than the geothermal water outlet 313. With the above configuration, the separation vessel 31 can generate a swirling flow inside to separate solids, liquids, or gases contained in the geothermal water.

[0035] The gas analyzer 32 is connected to the gas outlet 314 of the separation vessel 31. The gas analyzer 32 measures, for example, the concentration of oxygen and the concentration of carbon dioxide.

[0036] The liquid analyzer 33 is connected to the liquid outlet 316 of the separation container 31. The liquid analyzer 33 measures, for example, pH, dielectric constant, and dissolved ion concentration.

[0037] As described above, the separation vessel 31 has the function of separating solids, liquids, or gases contained in the geothermal water, and also has the function of collecting or depositing scale for analysis within the separation vessel 31. Therefore, the separation vessel 31 may have a metal mesh, ceramic beads, or the like inside in order to accelerate the collection or deposition of scale within the separation vessel 31.

[0038] As shown in FIG. 1, the geothermal power generation system 1 may include a recovery tank 10 connected to the first solids outlet 315 (see FIG. 2) and the second solids outlet 319 (see FIG. 2) of the analysis device 30, and configured to store solids discharged from the first solids outlet 315 and the second solids outlet 319.

[0039] The geothermal power generation system 1 may include a fourth valve V4 provided in a flow path between the first solids discharge outlet 315 and the second solids discharge outlet 319 and the collection tank 10. Specifically, the geothermal power generation system 1 may include a fifth pipe L5 that connects the first solids discharge outlet 315 and the second solids discharge outlet 319 to an inlet of the collection tank 10, and a fourth valve V4 that is provided midway along the fifth pipe L5 and opens and closes the flow path of the fifth pipe L5. The solids discharged from the first solids discharge outlet 315 and the second solids discharge outlet 319 flow into the collection tank 10 via the fifth pipe L5 and are stored therein.

[0040] The recovery tank 10 may have a water level meter 11. This allows the amount of solids contained in the recovery tank 10 to be detected, and when the water level meter 11 reaches a specified value, the solids in the recovery tank 10 can be discarded.

[0041] The control device 40 determines at least one type of chemical (cleaning agent) from among multiple candidate chemicals (cleaning agents) based on the analysis results of the analysis device 30, and controls the supply of the chemical (cleaning agent). The multiple candidate chemicals may include, for example, chemicals including two or more selected from an acidic chemical, a basic chemical, a chelating agent, a hydrogen peroxide-based chemical, a dispersant, and a catalase-based chemical.

[0042] Acidic agents can be used to dissolve calcium-based scale. Examples of acidic agents include sulfuric acid, hydrochloric acid, acetic acid, and citric acid. Basic agents can be used to dissolve silica-based scale (amorphous silica). Examples of basic agents include sodium hydroxide, potassium hydroxide, and ammonium salts. Chelating agents can be used to mask dissolved metals in geothermal water by adjusting the pH before using other agents, thereby preventing waste of other agents. Examples of chelating agents include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), trimethanolamine, and sodium gluconate. Hydrogen peroxide-based agents can be used to dissolve soft mud. Examples of hydrogen peroxide-based agents include hydrogen peroxide solution. Dispersants can be used to disperse and remove scale adhering to the inner walls of pipes, etc. Examples of dispersants include sodium polyacrylate, various surfactants, etc. Catalase-based agents can be used to decompose hydrogen peroxide-based agents remaining in geothermal water after the use of hydrogen peroxide-based agents.

[0043] Specifically, the control device 40 determines at least one chemical agent from among a plurality of candidate chemical agents based on the gas analysis results of the analysis device 30, and controls the supply of the chemical agent. For example, the control device 40 introduces a hydrogen peroxide-based chemical agent into the separation container 31 of the analysis device 30, and after reacting the hydrogen peroxide-based chemical agent with the scale accumulated in the separation container 31, determines that the main component of the scale is sludge if the oxygen concentration detected by the gas analyzer 32 is equal to or greater than a specified value, and determines that the main component of the scale is calcium carbonate or amorphous silica if the oxygen concentration detected by the gas analyzer 32 is equal to or less than the specified value or zero. If it is determined that the main component of the scale is calcium carbonate or amorphous silica, an acidic agent is introduced into the separation container 31, and after the acidic agent is reacted with the scale accumulated in the separation container 31, if the concentration of carbon dioxide detected by the gas analyzer 32 is equal to or higher than a specified value, it is determined that the main component of the scale is calcium carbonate, and if the concentration of carbon dioxide detected by the gas analyzer 32 is equal to or lower than a specified value or is zero, it is determined that the main component of the scale is amorphous silica or iron rust. At least one optimal agent is selected from multiple candidate agents for the main component of the scale determined as described above.

[0044] Before determining the chemical, the control device 40 may introduce geothermal water into the analysis line L11 and the analysis device 30 with the fourth valve V4 closed, collect the separated solids in the separation container 31, and then close the first valve V1, the second valve V2, and the third valve V3. Then, the chemical addition device 50 may supply an acidic chemical or a hydrogen peroxide-based chemical to the analysis line L11. The analysis device 30 may analyze the gas generated by the chemical reaction between the solids and the acidic chemical or the hydrogen peroxide-based chemical. Furthermore, if the control device 40 determines that the main component of the scale is sludge, it may select a hydrogen peroxide-based chemical as the first chemical to be used and a chemical other than a hydrogen peroxide-based chemical as the second chemical to be used. Furthermore, if the control device 40 determines that the main component of the scale is calcium carbonate, it may select an acidic chemical as the first chemical to be used and a chemical other than an acidic chemical as the second chemical to be used.

[0045] The chemical addition device 50 may include a plurality of chemical tanks 51 a, 51 b, and 51 c each containing a plurality of chemical candidate drugs, a chemical injection pump 52 for introducing the chemicals into the third pipe L3, a water tank 53 for containing water and disposed upstream of the chemical tanks 51 a, 51 b, and 51 c, and a liquid supply pump 54 for introducing water into the third pipe L3. The number of chemical tanks 51 a, 51 b, and 51 c is three in the example shown in FIG. 1 , but is not limited thereto and may be four or more depending on the number of chemical candidate drugs.

[0046] The water stored in the water tank 53 is water used to wash away any previous chemicals remaining in the sixth pipe L6 when changing the type of chemical introduced into the third pipe L3, and may be, for example, one type selected from tap water, river water, and distilled water.

[0047] The chemical addition device 50 may have a sixth pipe L6 connecting the discharge port of the liquid feed pump 54 and the suction port of the chemical injection pump 52, a seventh pipe L7 branching from the sixth pipe L6 and connecting to the discharge port of the chemical tank 51 a, an eighth pipe L8 branching from the sixth pipe L6 and connecting to the discharge port of the chemical tank 51 b, and a ninth pipe L9 branching from the sixth pipe L6 and connecting to the discharge port of the chemical tank 51 c. The chemical addition device 50 may also have a valve V8a provided in the seventh pipe L7 for opening and closing the flow path of the seventh pipe L7, a valve V8b provided in the eighth pipe L8 for opening and closing the flow path of the eighth pipe L8, and a valve V8c provided in the ninth pipe L9 for opening and closing the flow path of the ninth pipe L9.

[0048] The chemical addition device 50 may include a tenth pipe L10 connected to the chemical inlet of the recovery tank 10 downstream of the seventh pipe L7, the eighth pipe L8, and the ninth pipe L9, and a seventh valve V7 provided midway through the tenth pipe L10 and opening and closing the flow path of the tenth pipe L10. The chemical addition device 50 can introduce a chemical into the chemical inlet of the recovery tank 10 via the tenth pipe L10. By introducing a chemical into the chemical inlet of the recovery tank 10, solids contained in the recovery tank 10 can be dissolved. The chemical introduced into the chemical inlet of the recovery tank 10 is preferably a chemical capable of dissolving solids such as ooze and colloids, and examples thereof include hydrogen peroxide-based chemicals, basic chemicals, fluoride-based chemicals, and mixtures of chelating agents and basic chemicals. Basic chemicals and fluoride-based chemicals can be used to dissolve silica-based colloids. The basic chemicals can be the same as the candidate chemicals described above. Examples of fluoride-based drugs include hydrofluoric acid. A mixture of a chelating agent and a basic drug can be used to dissolve calcium-based colloids. The chelating agent can be the same as the drug candidates mentioned above.

[0049] The recovery tank 10 may have a function for adjusting pressure. Specifically, when excessive pressure exceeding a specified value is applied to the chemical injection pump 52 by the chemical or water flowing through the sixth pipe L6, the control device 40 sends a signal to the seventh valve V7 to open the seventh valve V7. This allows the chemical or water flowing through the sixth pipe L6 to flow into the recovery tank 10 via the tenth pipe L10, thereby reducing the pressure on the chemical injection pump 52.

[0050] The geothermal power generation system 1 preferably includes a heater or heat exchanger to increase the temperature of the fluid and improve the effectiveness of the chemical agent when the temperature of the geothermal water to which the chemical agent is added drops, etc. The heater or heat exchanger may be provided, for example, midway along the first pipe L1 downstream of the chemical agent supply port 5.

[0051] The control device 40 may be capable of determining the cleaning state based on the analysis results of the components contained in the fluid analyzed by the analysis device 30 after the fluid, in which a chemical agent has been added to geothermal water flowing through the third pipe L3 by the chemical agent addition device 50, is circulated through the chemical supply line L12, the first pipe L1, the second pipe L2, and the third pipe L3. As cleaning progresses, the inner walls of the pipes become more exposed, and iron constituting the pipes dissolves into the fluid, increasing the concentration of iron ions contained in the fluid. Therefore, the analysis results of the components contained in the fluid analyzed by the analysis device 30 may be the concentration of iron ions. For example, the control device 40 may determine that cleaning is complete when the concentration of iron ions reaches 100 ppm. The analysis results of the components contained in the fluid analyzed by the analysis device 30 may be the dielectric constant.

[0052] The geothermal power generation system 1 includes a pressure gauge 14 installed in the second chemical supply line L12b and a pressure gauge 15 installed in the third pipe L3, and the control device 40 may determine that cleaning is complete when the differential pressure between the pressure detected by the pressure gauge 14 and the pressure detected by the pressure gauge 15 becomes equal to or less than a specified value. When scale adheres to the inner walls of the first pipe L1 and the second pipe L2, the cross-sectional area of ​​the flow path of the first pipe L1 and the second pipe L2 decreases. Therefore, the cleaning status can be determined based on the differential pressure detected by the pressure gauge 14 located upstream of the first pipe L1 and the second pipe L2 and the pressure gauge 15 located downstream of the first pipe L1 and the second pipe L2.

[0053] The geothermal power generation system 1 is equipped with a flow meter 13 installed in the first pipe L1 downstream of the circulation pump 12, and the control device 40 may determine that cleaning is complete when the flow rate detected by the flow meter 13 reaches the flow rate at the start of operation (start of power generation) or a specified flow rate.

[0054] The geothermal power generation system 1 may include a ninth valve V9 provided in the second chemical supply line L12b and a tenth valve V10 provided in the third pipe L3. The ninth valve V9 and the tenth valve V10 may be flow control valves.

[0055] The control device 40 is capable of controlling each of the first to seventh valves V1 to V7, valve V8a, valve V8b, valve V8c, ninth valve V9, tenth valve V10, and bypass valve V11, and can switch the flow paths in the geothermal power generation system 1 or control the flow rate of the fluid flowing through the flow paths.

[0056] 3 is a flow diagram illustrating the cleaning method according to the first embodiment. As shown in Fig. 3, the method for cleaning scale in the geothermal power generation system 1 includes a step of performing normal operation (step S1), a step of introducing geothermal water into the analyzer 30 after the normal operation (step S2), a step of analyzing the scale components contained in the introduced geothermal water in the analyzer 30 (step S3), a step of determining at least one chemical (cleaning agent) from among multiple candidate chemicals (cleaning agents) based on the analysis results of the analyzer 30 (step S4), and a step of supplying the determined chemical from the chemical supply port 5 to clean the first pipe L1 and the second pipe L2 (step S5).

[0057] In the method of cleaning scale in the geothermal power generation system 1, it is preferable to start step S3 two to three weeks after the start of step S2, in order to collect or deposit the scale required for analysis in step S3 inside the analysis device 30.

[0058] The method for cleaning scale in the geothermal power generation system 1 further includes a step (step S6) of introducing the fluid (including geothermal water and chemicals) after cleaning the first pipe L1 and the second pipe L2 into the analysis device 30, analyzing the components contained in the introduced fluid in the analysis device 30, and determining whether or not the cleaning is complete (cleaning status) based on the analysis results of the analysis device 30.If it is determined that the cleaning is complete (step S6: YES), a step (step S7) of performing residue and wastewater treatment is carried out, and the process returns to the step of performing normal operation (step S1).If it is determined that the cleaning is not complete (step S6: NO), the process returns to step S5 again, and steps S5 and S6 may be repeated until it is determined that the cleaning is complete.

[0059] In the process of treating residue and wastewater, the geothermal power generation system 1 recovers chemicals from the wastewater after cleaning, and then treats impurities and other substances generated in the process of refining the chemicals before returning them to the reinjection well 4. The geothermal power generation system 1 also recovers residues that cannot be returned to the reinjection well 4 and disposes of them as industrial waste.

[0060] Next, the configuration for recovering chemicals in the geothermal power generation system 1 will be described. Figure 4 is a schematic diagram of the chemical recovery line L14 in the geothermal power generation system 1 according to the first embodiment. As shown in Figure 4, the geothermal power generation system 1 includes a chemical recovery line L14 that branches off from the second pipe L2 downstream of the third pipe L3 and is connected to the second pipe L2. The geothermal power generation system 1 also includes, in order from upstream, a waste liquid recovery section 61, a scale separation section 62, a first chemical recovery section 63, an impurity separation section 64, a second chemical recovery section 65, a chemical purification section 66, and a regenerated chemical tank 69, as well as a waste liquid adjustment device 67, provided along the chemical recovery line L14.

[0061] The chemical recovery line L14 may include a first chemical recovery line L14a connecting the waste liquid recovery section 61, the scale separation section 62, the first chemical recovery section 63, the impurity separation section 64, the second chemical recovery section 65, the chemical purification section 66, and the regenerated chemical tank 69, and a second chemical recovery line L14b branching off from the first chemical recovery line L14a between the chemical purification section 66 and the regenerated chemical tank 69. The chemical recovery line L14 may also include a third chemical recovery line L14c branching off from the second chemical recovery line L14b and connecting to the chemical purification section 66, a fourth chemical recovery line L14d branching off from the second chemical recovery line L14b and connecting to the impurity separation section 64, and a fifth chemical recovery line L14e branching off from the second chemical recovery line L14b and connecting to the chemical purification section 66.

[0062] The post-cleaning waste liquid that flows into the chemical recovery line L14 is purified as it passes through the waste liquid recovery section 61, scale separation section 62, first chemical recovery section 63, impurity separation section 64, second chemical recovery section 65, and chemical purification section 66, and the regenerated chemical purified from the waste liquid is stored in the regenerated chemical tank 69. In addition, impurities and the like generated in the process of refining the waste liquid into the regenerated chemical are adjusted and then returned to the reinjection well 4 from the second chemical recovery line L14b via the third chemical recovery line L14c, fourth chemical recovery line L14d, and fifth chemical recovery line L14e.

[0063] The waste liquid recovery section 61 stores the waste liquid after cleaning the first pipe L1 and the second pipe L2.

[0064] The scale separation unit 62 separates the waste liquid into scale-containing material and primary chemical-containing material. The scale-containing material is a solid or liquid, and the primary chemical-containing material is a liquid containing the chemical supplied from the chemical supply port 5. That is, the scale separation unit 62 may separate into solid and liquid, or into liquid and liquid. The scale separation unit 62 may be, for example, a filtration device, a retention tank, a centrifuge, or a reactor. The retention tank stores the waste liquid, promotes the polymerization reaction of silica in the waste liquid, and retains the waste liquid until the silica-based insoluble components have sufficiently coagulated and precipitated. The reactor is a container for chemically reacting the waste liquid.

[0065] The first drug recovery section 63 contains the primary drug-containing material separated in the scale separation section 62 .

[0066] Impurity separation section 64 separates the primary drug-containing material discharged from first drug recovery section 63 into primary impurities and secondary drug-containing material. The secondary drug-containing material is a liquid containing the drug supplied from drug supply port 5, and the drug concentration in the secondary drug-containing material is higher than the drug concentration in the primary drug-containing material. Impurity separation section 64 may be, for example, a reactor, a distillation device such as a fractional distillation device, an extraction device, or the like.

[0067] The second drug recovery section 65 contains the secondary drug-containing material separated in the impurity separation section 64 .

[0068] The chemical purification unit 66 purifies the secondary chemical-containing material discharged from the second chemical recovery unit 65 and separates it into secondary impurities and a regenerated chemical. The regenerated chemical is a liquid containing the chemical supplied from the chemical supply port 5, and the concentration of the regenerated chemical is higher than the concentration of the chemical in the secondary chemical-containing material. The chemical purification unit 66 may be, for example, a reactor, a distillation device such as a fractional distillation device, an extraction device, or the like.

[0069] The regenerative chemical tank 69 stores the regenerative chemical. The regenerative chemical tank 69 may be connected to the sixth pipe L6 upstream of the chemical injection pump 52. This allows the geothermal power generation system 1 to supply the regenerative chemical from the chemical supply port 5, thereby enabling the chemical to be reused.

[0070] The waste liquid adjustment device 67 supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid contained in the scale separation unit 62, the impurity separation unit 64, and the chemical purification unit 66. The waste liquid adjustment device 67 may include multiple tanks each containing a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, multiple pumps connected to the tanks and discharging the silica concentration adjuster, the pH adjuster, or the ion concentration adjuster, respectively, and flow meters provided downstream of the pumps. The waste liquid adjustment device 67 may also include a heating / cooling device. The waste liquid adjustment device 67 can, for example, lower the temperature of the fluid to precipitate dissolved silica as silica scale and separate the silica scale. The geothermal power generation system 1 may include multiple control devices 40, and the waste liquid adjustment device 67 may include a control device 40.

[0071] Examples of silica concentration adjusters include water glass, or silicates such as sodium silicate and sodium silicate hexahydrate. Examples of pH adjusters include sulfuric acid, hydrochloric acid, nitric acid, sodium hydroxide, sodium carbonate, and sodium bicarbonate. Examples of ion concentration adjusters include sodium carbonate, sodium bicarbonate, sodium sulfate, sodium chloride, and sodium hydroxide. The waste liquid adjuster 67 may also include, for example, an ion separation membrane, an ion exchange resin, or the like.

[0072] The waste liquid adjustment device 67 is connected to the scale separation section 62, the impurity separation section 64, and the chemical refining section 66. In the example shown in FIG. 4, there are multiple waste liquid adjustment devices 67, but there may be only one. The waste liquid adjustment device 67 supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the scale separation section 62, or adjusts the temperature of the fluid contained in the scale separation section 62. The waste liquid adjustment device 67 also supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the impurity separation section 64, or adjusts the temperature of the primary chemical-containing material contained in the impurity separation section 64. The waste liquid adjustment device 67 also supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the chemical refining section 66, or adjusts the temperature of the secondary chemical-containing material contained in the chemical refining section 66.

[0073] The geothermal power generation system 1 may include a first analyzer 68a connected to the waste liquid recovery unit 61 and configured to measure the temperature, pH, dielectric constant, or dissolved ion concentration of the waste liquid stored in the waste liquid recovery unit 61. Based on the measurement results of the first analyzer 68a, the control device 40 may supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster from the waste liquid adjustment device 67 to the scale separation unit 62, or may cause the waste liquid adjustment device 67 to adjust the temperature of the waste liquid stored in the scale separation unit 62. For example, based on the measurement results of the first analyzer 68a, the control device 40 may calculate the concentration of the silica concentration adjuster, pH adjuster, or ion concentration adjuster required to separate the waste liquid into scale-containing matter and primary chemical-containing matter, convert this into a flow rate, and send a command to the pump of the waste liquid adjustment device 67 to discharge the predetermined flow rate. The control device 40 calculates the temperature required to separate the scale-containing material and the primary drug-containing material, for example, based on the measurement results of the first analyzer 68a, and sends a command to the heating and cooling device of the waste liquid adjustment device 67 to achieve the specified temperature.

[0074] The geothermal power generation system 1 may include a flocculant tank 70a connected to the scale separation unit 62 and containing a flocculant, a flocculant pump 71a that introduces the flocculant into the scale separation unit 62, a flow meter 72a that measures the flow rate of the flocculant, and an eleventh valve V13 that is provided downstream of the flocculant tank 70a, the flocculant pump 71a, and the flow meter 72a and opens and closes a flow path through which the flocculant flows. The control device 40 may send a command to the flocculant pump 71a to discharge the flocculant based on the measurement results of the first analyzer 68a. Examples of flocculants include solutions containing silica, calcium, aluminum, iron, or the like.

[0075] The geothermal power generation system 1 may include a second analyzer 68b connected to the first chemical recovery unit 63 and configured to measure the temperature, pH, dielectric constant, or dissolved ion concentration of the primary chemical-containing material contained in the first chemical recovery unit 63. Based on the measurement results of the second analyzer 68b, the control device 40 may supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster from the waste liquid adjustment device 67 to the impurity separation unit 64, or may adjust the temperature of the primary chemical-containing material contained in the impurity separation unit 64 using the waste liquid adjustment device 67. For example, based on the measurement results of the second analyzer 68b, the control device 40 may calculate the concentration of the silica concentration adjuster, pH adjuster, or ion concentration adjuster required to separate the primary chemical-containing material into primary impurities and secondary chemical-containing material, convert this into a flow rate, and send a command to the pump of the waste liquid adjustment device 67 to discharge a predetermined flow rate.

[0076] The geothermal power generation system 1 may include a dispersant tank 70b connected to the impurity separation unit 64 and containing a dispersant, a dispersant pump 71b that introduces the dispersant into the impurity separation unit 64, a flow meter 72b that measures the flow rate of the dispersant, and a twelfth valve V14 that is provided downstream of the dispersant tank 70b, the dispersant pump 71b, and the flow meter 72b and opens and closes a flow path through which the dispersant flows. The control device 40 may send a command to the dispersant pump 71b to discharge the dispersant based on the measurement results of the second analyzer 68b. Examples of dispersants include sodium polyacrylate and various surfactants.

[0077] The geothermal power generation system 1 may include a third analyzer 68c connected to the second chemical recovery unit 65 and configured to measure the temperature, pH, dielectric constant, or dissolved ion concentration of the secondary chemical-containing material contained in the second chemical recovery unit 65. Based on the measurement results of the third analyzer 68c, the control device 40 may supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster from the waste liquid adjustment device 67 to the chemical purification unit 66, or may adjust the temperature of the secondary chemical-containing material contained in the chemical purification unit 66 using the waste liquid adjustment device 67.

[0078] The geothermal power generation system 1 may include a fourth analyzer 68d connected to the chemical purification unit 66 and configured to measure the concentration of the purified regenerated chemical in the chemical purification unit 66. The geothermal power generation system 1 may also include a first three-way valve V12 provided at the branch point between the first chemical recovery line L14a and the second chemical recovery line L14b and configured to switch between a state in which the chemical purification unit 66 communicates with the regenerated chemical tank 69 and a state in which the chemical purification unit 66 communicates with the second chemical recovery line L14b. When the concentration of the regenerated chemical measured by the fourth analyzer 68d reaches a specified value and the control device 40 determines that purification is complete, the control device 40 may control the first three-way valve V12 to communicate between the chemical purification unit 66 and the regenerated chemical tank 69. Specifically, when the concentration of the regenerated drug measured by the fourth analyzer 68d reaches the same concentration as the concentration of the drug when it was stored in the drug tank 51a, 51b, 51c before use, the control device 40 may control the first three-way valve V12 to connect the drug purification unit 66 and the regenerated drug tank 69.

[0079] The geothermal power generation system 1 may include a scale-containing material recovery tank 73, a first adjustment liquid tank 74, and a fifth analyzer 68e connected to the scale-containing material recovery tank 73, which are provided midway along the third chemical recovery line L14c. The first adjustment liquid tank 74 is provided downstream of the scale-containing material recovery tank 73. The waste liquid adjustment device 67 may be connected to the third chemical recovery line L14c between the scale-containing material recovery tank 73 and the first adjustment liquid tank 74.

[0080] The scale-containing material recovery tank 73 stores the scale-containing material.

[0081] The first adjusting liquid tank 74 contains the scale-containing material after the silica concentration, pH, or ion concentration has been adjusted (adjusted scale-containing material).

[0082] The fifth analyzer 68e measures the temperature, pH, dielectric constant, or dissolved ion concentration of the scale-containing material contained in the scale-containing material recovery tank 73. Then, based on the measurement results of the fifth analyzer 68e, the control device 40 may cause the waste liquid adjustment device 67 to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid (scale-containing material) flowing through the third chemical recovery line L14c between the scale-containing material recovery tank 73 and the first adjustment liquid tank 74. For example, based on the measurement results of the fifth analyzer 68e, the control device 40 calculates the concentration of the silica concentration adjuster, pH adjuster, or ion concentration adjuster required to return to the reinjection well 4, converts this into a flow rate, and sends a command to a pump of the waste liquid adjustment device 67 that discharges the silica concentration adjuster, pH adjuster, or ion concentration adjuster so as to discharge a predetermined flow rate.

[0083] The geothermal power generation system 1 may include a primary impurity recovery tank 76, a second adjustment liquid tank 77, and a sixth analyzer 68f connected to the primary impurity recovery tank 76, which are provided midway along the fourth chemical recovery line L14d. The second adjustment liquid tank 77 is provided downstream of the primary impurity recovery tank 76. The waste liquid adjustment device 67 may be connected to the fourth chemical recovery line L14d between the primary impurity recovery tank 76 and the second adjustment liquid tank 77.

[0084] The primary impurities recovery tank 76 contains the primary impurities.

[0085] The second adjusting liquid tank 77 stores the primary impurities (adjusted primary impurities) after the silica concentration, pH, or ion concentration has been adjusted.

[0086] The sixth analyzer 68f measures the temperature, pH, dielectric constant, or dissolved ion concentration of the primary impurities contained in the primary impurity recovery tank 76. Based on the measurement results of the sixth analyzer 68f, the control device 40 may cause the waste liquid adjustment device 67 to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid (primary impurities) flowing through the fourth chemical recovery line L14d between the primary impurity recovery tank 76 and the second adjustment liquid tank 77. For example, based on the measurement results of the sixth analyzer 68f, the control device 40 calculates the concentration of the silica concentration adjuster, pH adjuster, or ion concentration adjuster required to return to the reinjection well 4, converts this into a flow rate, and sends a command to a pump of the waste liquid adjustment device 67 that discharges the silica concentration adjuster, pH adjuster, or ion concentration adjuster so as to discharge a predetermined flow rate.

[0087] The geothermal power generation system 1 may include a secondary impurity recovery tank 78, a third adjustment liquid tank 79, and a seventh analyzer 68g connected to the secondary impurity recovery tank 78, which are provided midway along the fifth chemical recovery line L14e. The third adjustment liquid tank 79 is provided downstream of the secondary impurity recovery tank 78. The waste liquid adjustment device 67 may be connected to the fifth chemical recovery line L14e between the secondary impurity recovery tank 78 and the third adjustment liquid tank 79.

[0088] The secondary impurities recovery tank 78 contains the secondary impurities.

[0089] The third adjusting liquid tank 79 contains secondary impurities (adjusted secondary impurities) after the silica concentration, pH, or ion concentration has been adjusted.

[0090] The seventh analyzer 68g measures the temperature, pH, dielectric constant, or dissolved ion concentration of the secondary impurities contained in the secondary impurity recovery tank 78. Then, based on the measurement results of the seventh analyzer 68g, the control device 40 may cause the waste liquid adjustment device 67 to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid (secondary impurities) flowing through the fourth chemical recovery line L14d between the secondary impurity recovery tank 78 and the second adjustment liquid tank 77. For example, based on the measurement results of the seventh analyzer 68g, the control device 40 calculates the concentration of the silica concentration adjuster, pH adjuster, or ion concentration adjuster required to return to the reinjection well 4, converts this into a flow rate, and sends a command to a pump of the waste liquid adjustment device 67 that discharges the silica concentration adjuster, pH adjuster, or ion concentration adjuster so as to discharge a predetermined flow rate.

[0091] The geothermal power generation system 1 may include a residue recovery tank 75 provided midway along the second chemical recovery line L14b.

[0092] The residue recovery tank 75 is located upstream of the branch point between the fifth chemical recovery line L14e and the second chemical recovery line L14b. The residue recovery tank 75 stores residue discharged from the first adjustment liquid tank 74, the second adjustment liquid tank 77, and the third adjustment liquid tank 79. Here, residue refers to adjusted scale-containing materials, adjusted primary impurities, and adjusted secondary impurities that cannot be returned to the reinjection well 4 because their silica concentration, pH, or ion concentration are outside the specified range. The residue recovery tank 75 may also store the regenerating chemical when the regenerating chemical tank 69 is full. In this case, the control device 40 switches the first three-way valve V12 to a state that connects the regenerating chemical tank 69 and the second chemical recovery line L14b.

[0093] The geothermal power generation system 1 may be provided with an eighth analyzer 68h connected to the first adjustment liquid tank 74 and a second three-way valve V15 provided at the branch point between the third chemical recovery line L14c and the second chemical recovery line L14b.

[0094] The eighth analyzer 68 h measures the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted scale-containing material contained in the first adjusting liquid tank 74 .

[0095] The second three-way valve V15 is a valve that can be switched between a state in which the first adjustment liquid tank 74 and the reinjection well 4 are in communication with each other and a state in which the first adjustment liquid tank 74 and the residue recovery tank 75 are in communication with each other. When the concentration of the scale-containing material after adjustment measured by the eighth analyzer 68h reaches a specified value, the control device 40 may control the second three-way valve V15 to be in a state in which the first adjustment liquid tank 74 and the reinjection well 4 are in communication with each other.

[0096] The geothermal power generation system 1 may be equipped with a ninth analyzer 68i connected to the second adjustment liquid tank 77 and a third three-way valve V16 provided at the branch point between the fourth chemical recovery line L14d and the second chemical recovery line L14b.

[0097] The ninth analyzer 68 i measures the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted primary impurities contained in the second adjustment liquid tank 77 .

[0098] The third three-way valve V16 is a valve that can be switched between a state in which the second adjustment liquid tank 77 and the reinjection well 4 are in communication with each other and a state in which the second adjustment liquid tank 77 and the residue recovery tank 75 are in communication with each other. When the concentration of the adjusted primary impurities measured by the ninth analyzer 68i reaches a specified value, the control device 40 may control the third three-way valve V16 to be in a state in which the second adjustment liquid tank 77 and the reinjection well 4 are in communication with each other.

[0099] The geothermal power generation system 1 may be equipped with a tenth analyzer 68j connected to the third adjustment liquid tank 79 and a fourth three-way valve V17 provided at the branch point between the fifth chemical recovery line L14e and the second chemical recovery line L14b.

[0100] The tenth analyzer 68 j measures the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted secondary impurities contained in the third adjustment liquid tank 79 .

[0101] The fourth three-way valve V17 is a valve that can be switched between a state in which the third adjustment liquid tank 79 communicates with the reinjection well 4 and a state in which the third adjustment liquid tank 79 communicates with the residue recovery tank 75. When the concentration of the adjusted secondary impurities measured by the tenth analyzer 68j reaches a specified value, the control device 40 may control the fourth three-way valve V17 to communicate with the third adjustment liquid tank 79 and the reinjection well 4.

[0102] The geothermal power generation system 1 is a geothermal power generation system equipped with a binary power generation device 20 having a medium evaporator 21, and is equipped with a gas-liquid separator 3, a first pipe L1, a first valve V1, a second pipe L2, an analytical device 30, a control device 40, a chemical supply port 5, a third pipe L3, a chemical recovery line L14, a waste liquid recovery section 61, a scale separation section 62, a first chemical recovery section 63, an impurity separation section 64, a second chemical recovery section 65, a chemical purification section 66, a regenerated chemical tank 69, and a waste liquid adjustment device 67, and the waste liquid adjustment device 67 is connected to the scale separation section 62, the impurity separation section 64, and the chemical purification section 66.

[0103] With this configuration, the geothermal power generation system 1 can supply an optimal chemical agent for the scale components through the chemical supply port 5 and circulate the chemical agent through the first pipe L1 and the second pipe L2, which are particularly prone to scale buildup, while the first valve V1 is closed to stop power generation and the geothermal power generation system 1 is in a closed state without being opened or disassembled. Therefore, the geothermal power generation system 1 can remove scale regardless of the scale components. Furthermore, the geothermal power generation system 1 can add chemical agents to geothermal water at relatively high temperatures after power generation is stopped and circulate the water through the first pipe L1 and the second pipe L2, thereby improving the effectiveness of the chemical agent. Furthermore, the wastewater after cleaning the first pipe L1 and the second pipe L2 is adjusted by the wastewater adjustment device 67 in the wastewater collection unit 61, the scale separation unit 62, the first chemical recovery unit 63, the impurity separation unit 64, the second chemical recovery unit 65, and the chemical purification unit 66. As the wastewater flows from the wastewater collection unit 61 to the chemical purification unit 66, scale-containing materials and impurities are sequentially separated and removed, and the resulting regenerating chemical is stored in the regenerating chemical tank 69. Therefore, the geothermal power generation system 1 can recover the regenerated chemicals refined from the waste liquid. As a result, the geothermal power generation system 1 can sufficiently remove scale and recover the chemicals used for cleaning.

[0104] The geothermal power generation system 1 is equipped with a first analyzer 68a, and the control device 40 supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster from the waste liquid adjustment device 67 to the scale separation section 62 based on the measurement results of the first analyzer 68a, or adjusts the temperature of the waste liquid contained in the scale separation section 62 using the waste liquid adjustment device 67.

[0105] With this configuration, the control device 40 controls the waste liquid conditioner 67 to supply an appropriate amount of silica concentration adjuster, pH adjuster, or ion concentration adjuster depending on the silica concentration, pH, or ion concentration of the waste liquid, or controls the waste liquid conditioner 67 to adjust the temperature to a predetermined level depending on the temperature of the fluid. Therefore, the scale separation unit 62 can sufficiently separate scale-containing matter from primary chemical-containing matter, and the chemical used in cleaning can be efficiently recovered.

[0106] The geothermal power generation system 1 is equipped with a second analyzer 68b, and the control device 40 supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster from the waste liquid adjustment device 67 to the impurity separation section 64 based on the measurement results of the second analyzer 68b, or causes the waste liquid adjustment device 67 to adjust the temperature of the primary drug-containing material contained in the impurity separation section 64.

[0107] With this configuration, the control device 40 supplies an appropriate amount of silica concentration adjuster, pH adjuster, or ion concentration adjuster from the waste liquid adjustment device 67 depending on the silica concentration, pH, or ion concentration of the primary chemical-containing material, or adjusts the temperature of the primary chemical-containing material to a predetermined value depending on the temperature of the primary chemical-containing material by the waste liquid adjustment device 67. Therefore, the impurity separation unit 64 can sufficiently separate the scale-containing material from the primary chemical-containing material, and the chemical used for cleaning can be efficiently recovered.

[0108] The geothermal power generation system 1 is equipped with a third analyzer 68c, and the control device 40 supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the chemical purification section 66 from the waste liquid adjustment device 67 based on the measurement results of the third analyzer 68c, or adjusts the temperature of the secondary chemical-containing material contained in the chemical purification section 66 using the waste liquid adjustment device 67.

[0109] With this configuration, the control device 40 supplies an appropriate amount of silica concentration adjuster, pH adjuster, or ion concentration adjuster from the waste liquid adjustment device 67 depending on the silica concentration, pH, or ion concentration of the secondary chemical-containing material, or adjusts the temperature of the secondary chemical-containing material to a predetermined value depending on the temperature of the secondary chemical-containing material by the waste liquid adjustment device 67. Therefore, the scale-containing material and the secondary chemical-containing material can be sufficiently separated in the chemical purification unit 66, and the chemical used for cleaning can be efficiently recovered.

[0110] In the geothermal power generation system 1, the chemical recovery line L14 has a first chemical recovery line L14a, a second chemical recovery line L14b, a third chemical recovery line L14c, a fourth chemical recovery line L14d, and a fifth chemical recovery line L14e.

[0111] With this configuration, the regenerating agent purified from the waste liquid is stored in the regenerating agent tank 69 via the first agent recovery line L14a, and the scale-containing matter, primary impurities, and secondary impurities separated during the purification process are adjusted and then returned from the second agent recovery line L14b to the reinjection well 4 via the third agent recovery line L14c, the fourth agent recovery line L14d, and the fifth agent recovery line L14e. Thus, the agent used for cleaning can be efficiently recovered, and the scale-containing matter, primary impurities, and secondary impurities can be returned to the reinjection well 4.

[0112] The geothermal power generation system 1 is equipped with a fourth analyzer 68d and a first three-way valve V12, and when the control device 40 determines that the concentration of the regenerated chemical measured by the fourth analyzer 68d has reached a specified value and purification has been completed, it controls the first three-way valve V12 to connect the chemical purification section 66 and the regenerated chemical tank 69.

[0113] With this configuration, the geothermal power generation system 1 can sufficiently remove scale even when a regenerative agent is used for cleaning.

[0114] The geothermal power generation system 1 includes a scale-containing material recovery tank 73, a first adjustment liquid tank 74, and a fifth analyzer 68e, and the control device 40 controls the waste liquid adjustment device 67 to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid flowing through the third chemical recovery line L14c between the scale-containing material recovery tank 73 and the first adjustment liquid tank 74 based on the measurement results of the fifth analyzer 68e.

[0115] With this configuration, the control device 40 can supply an appropriate amount of silica concentration adjuster, pH adjuster, or ion concentration adjuster from the waste liquid adjustment device 67 depending on the silica concentration, pH, or ion concentration in the scale-containing material recovery tank 73. Therefore, the geothermal power generation system 1 can return the scale-containing material to the reinjection well 4 after sufficiently adjusting it.

[0116] The geothermal power generation system 1 includes a primary impurity recovery tank 76, a second adjustment liquid tank 77, and a sixth analyzer 68f, and the control device 40 controls the waste liquid adjustment device 67 to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid flowing through the fourth chemical recovery line L14d between the primary impurity recovery tank 76 and the second adjustment liquid tank 77 based on the measurement results of the sixth analyzer 68f.

[0117] With this configuration, the control device 40 can supply an appropriate amount of silica concentration adjuster, pH adjuster, or ion concentration adjuster from the wastewater adjustment device 67 depending on the silica concentration, pH, or ion concentration in the primary impurity recovery tank 76. Therefore, the geothermal power generation system 1 can return the primary impurities to the reinjection well 4 after adequately adjusting them.

[0118] The geothermal power generation system 1 includes a secondary impurity recovery tank 78, a third adjustment liquid tank 79, and a seventh analyzer 68g, and the control device 40 controls the waste liquid adjustment device 67 to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid flowing through the fifth chemical recovery line L14e between the secondary impurity recovery tank 78 and the third adjustment liquid tank 79 based on the measurement results of the seventh analyzer 68g.

[0119] With this configuration, the control device 40 can supply an appropriate amount of silica concentration adjuster, pH adjuster, or ion concentration adjuster from the wastewater adjustment device 67 depending on the silica concentration, pH, or ion concentration in the secondary impurity recovery tank 78. Therefore, the geothermal power generation system 1 can return the secondary impurities to the reinjection well 4 after sufficiently adjusting them.

[0120] The geothermal power generation system 1 is equipped with an eighth analyzer 68h, a residue recovery tank 75, and a second three-way valve V15, and the control device 40 controls the second three-way valve V15 so that the first adjustment liquid tank 74 and the reduction well 4 are connected to each other when the concentration of adjusted scale-containing material measured by the eighth analyzer 68h is within a specified range.

[0121] With this configuration, the geothermal power generation system 1 can return the adjusted scale-containing material to the reinjection well 4 only if the concentration of the adjusted scale-containing material is within the specified range, and if the concentration of the adjusted scale-containing material is outside the specified range, it can be stored in the residue recovery tank 75.

[0122] The geothermal power generation system 1 is equipped with a ninth analyzer 68i and a third three-way valve V16, and the control device 40 controls the third three-way valve V16 so that the second adjustment liquid tank 77 and the reduction well 4 are connected when the concentration of adjusted scale-containing matter measured by the ninth analyzer 68i is within a specified range.

[0123] With this configuration, the geothermal power generation system 1 can return the adjusted primary impurities to the reinjection well 4 only if the concentration of the adjusted primary impurities is within the specified range, and if the concentration of the adjusted primary impurities is outside the specified range, it can be stored in the residue recovery tank 75.

[0124] The geothermal power generation system 1 is equipped with a tenth analyzer 68j and a fourth three-way valve V17, and the control device 40 controls the fourth three-way valve V17 so that the third adjustment liquid tank 79 and the reduction well 4 are connected when the concentration of adjusted scale-containing matter measured by the tenth analyzer 68j is within a specified range.

[0125] With this configuration, the geothermal power generation system 1 can return the adjusted secondary impurities to the reinjection well 4 only if the concentration of the adjusted secondary impurities is within the specified range, and if the concentration of the adjusted secondary impurities is outside the specified range, it can be stored in the residue recovery tank 75.

[0126] The geothermal power generation system 1 includes a second valve V2, a third pipe L3, a branching section 6 that can branch into an analysis line L11 and a chemical supply line L12, and a chemical addition device 50.

[0127] With this configuration, the geothermal power generation system 1 can introduce the geothermal water flowing through the second pipe L2 into the analysis device 30 via the analysis line L11 while maintaining a closed system without opening or disassembling the geothermal power generation system 1. Furthermore, by closing the first valve V1 and the second valve V2, an optimal chemical agent according to the components of the scale can be added to the geothermal water flowing through the third pipe L3, and the chemical agent can be circulated from the chemical supply port 5 through the chemical supply line L12 to the first pipe L1 and the second pipe L2, thereby cleaning the first pipe L1 and the second pipe L2.

[0128] The geothermal power generation system 1 includes a third valve, which allows the third valve V3 to be closed and the geothermal water or chemicals flowing through the third pipe L3 to flow only through the analytical line L11, allowing the analyzer 30 to analyze the scale components contained in the geothermal water before the chemicals are circulated through the chemical supply line L12.

[0129] The geothermal power generation system 1 includes a fourth pipe L4. This allows geothermal water discharged from the first outlet 34 of the analyzer 30 to be supplied to the first pipe L1 from the chemical supply port 5 via the chemical supply line L12, and used for binary power generation.

[0130] The geothermal power generation system 1 includes a flow meter 9, and the analysis device 30 includes a separation vessel 31, a gas analyzer 32, and a liquid analyzer 33. This allows the geothermal power generation system 1 to adjust the flow rate of geothermal water flowing into the analysis line L11 so that it is smaller than the flow rate of geothermal water flowing into the chemical supply line L12, separate the geothermal water into solids, liquids, or gases in the separation vessel 31, and analyze the separated gases or liquids using the gas analyzer 32 or liquid analyzer 33, respectively. Thus, the analysis device 30 can determine the optimal chemical depending on the scale components contained in the geothermal water.

[0131] In the geothermal power generation system 1, the control device 40 determines at least one chemical agent from among multiple candidate chemical agents based on the gas analysis results of the analyzer 30, and controls the supply of the chemical agent. With this configuration, the chemical agent is introduced into the separation vessel 31 of the analyzer 30, and the chemical agent is allowed to react with the scale accumulated in the separation vessel 31. Then, the components contained in the scale can be determined based on the analysis results of the generated gas. Thus, the analyzer 30 can determine the optimal chemical agent according to the components of the scale contained in the geothermal water.

[0132] In the geothermal power generation system 1, the gas analyzer 32 measures the oxygen concentration and the carbon dioxide concentration. This allows the control device 40 to introduce a hydrogen peroxide-based chemical or an acidic chemical into the separation vessel 31 of the analysis device 30, react the hydrogen peroxide-based chemical or the acidic chemical with the scale accumulated in the separation vessel 31, and then determine whether the components contained in the scale are ooze, calcium carbonate, amorphous silica, or iron rust based on the concentrations of oxygen and carbon dioxide generated. Thus, the control device 40 can determine the optimal chemical depending on the components of the scale contained in the geothermal water.

[0133] In the geothermal power generation system 1, the liquid analyzer 33 measures pH, dielectric constant, and dissolved ion concentration. The control device 40 then controls the liquid analyzer 33 to detect the pH of the fluid introduced into the analyzer 30 and, based on the detected pH, controls the supply of an acidic or basic chemical to the fluid to achieve a pH necessary for dissolving the scale, thereby removing the scale. When a chelating agent is used as the chemical, the liquid analyzer 33 detects the pH and controls the supply of an acidic or basic chemical to the fluid to achieve an appropriate pH based on the detected pH, thereby adjusting the pH of the fluid. The control device 40 also controls the liquid analyzer 33 to detect the dielectric constant or ion concentration of the fluid introduced into the analyzer 30 and can determine the cleaning state based on the detected dielectric constant or dissolved ion concentration. As described above, the geothermal power generation system 1 is able to sufficiently remove scale regardless of the scale's components.

[0134] In the geothermal power generation system 1, the separation vessel 31 generates a swirling flow inside to separate the solid, liquid, or gas contained in the geothermal water, thereby enabling the analysis device 30 in the geothermal power generation system 1 to efficiently analyze the scale components contained in the geothermal water.

[0135] In the geothermal power generation system 1, the separation vessel 31 has a cylindrical shape and includes a housing 311, a geothermal water inlet 312, a geothermal water outlet 313, a first chamber R1, a second chamber R2, and a third chamber R3. The first chamber R1, the second chamber R2, and the third chamber R3 are connected at the center, the first chamber R1 has a gas outlet 314, the second chamber R2 has a first solid outlet 315, and the third chamber R3 has a second solid outlet 319 and a liquid outlet 316. The geothermal water inlet 312 is positioned vertically below the geothermal water outlet 313.

[0136] With the above configuration, the separation vessel 31 generates a swirling flow inside, allowing the separation vessel 31 to efficiently separate the solid, liquid, or gas contained in the geothermal water. Therefore, the geothermal power generation system 1 can efficiently analyze the scale components contained in the geothermal water using the analysis device 30.

[0137] The geothermal power generation system 1 includes a collection tank 10. This allows the geothermal power generation system 1 to remove solids that are not required for analysis by the analysis device 30.

[0138] In the geothermal power generation system 1, the chemical addition device 50 has multiple chemical tanks 51a, 51b, and 51c, a chemical injection pump 52, a water tank 53, and a liquid supply pump 54. Therefore, the geothermal power generation system 1 can supply the optimal chemical from multiple candidate chemicals according to the components of the scale through the chemical supply port 5. Therefore, the geothermal power generation system 1 can remove scale regardless of the components of the scale.

[0139] In the geothermal power generation system 1, the multiple types of chemical candidate include two or more selected from an acidic chemical, a basic chemical, a chelating agent, a hydrogen peroxide-based chemical, a dispersant, and a catalase-based chemical, which allows the geothermal power generation system 1 to supply from the chemical supply port 5 the chemical that is optimal for each of the soft mud, calcium carbonate, amorphous silica, and iron rust contained in the scale.

[0140] The geothermal power generation system 1 is equipped with a fourth valve V4, and before determining the chemical, the control device 40 closes the fourth valve V4 and introduces geothermal water into the analytical line L11 and the analytical device 30, collects the separated solids in the separation container 31, and then closes the first valve V1, the second valve V2, and the third valve V3, and supplies an acidic chemical or a hydrogen peroxide-based chemical to the analytical line L11 using the chemical addition device 50, and the analytical device 30 analyzes the gas generated by the chemical reaction between the solids and the acidic chemical or the hydrogen peroxide-based chemical.

[0141] In the geothermal power generation system 1, the control device 40 circulates a fluid in which a chemical has been added to geothermal water flowing through the third pipe L3 by the chemical addition device 50 through the chemical supply line L12, the first pipe L1, the second pipe L2, and the third pipe L3, and then can determine the cleaning state based on the analysis results of the components contained in the fluid analyzed by the analysis device 30. Therefore, the geothermal power generation system 1 can sufficiently remove scale regardless of the scale components.

[0142] In the geothermal power generation system 1, the water stored in the water tank is one type selected from tap water, river water, and distilled water. As a result, even if the geothermal water in the first pipe L1 and the second pipe L2 is drained before cleaning, the geothermal power generation system 1 can introduce the water stored in the water tank together with the chemical into the third pipe L3 and supply it to the first pipe L1 from the chemical supply port 5 via the chemical supply line L12.

[0143] Second Embodiment A geothermal power generation system 100 according to a second embodiment will be described. In the geothermal power generation system 100 according to the second embodiment, normal operation (power generation) is stopped to clean the reduction line L100. First, the configuration for cleaning in the geothermal power generation system 100 will be described.

[0144] Figure 5 is a schematic diagram of a geothermal power generation system according to the second embodiment. As shown in Figure 5, the geothermal power generation system 100 includes a gas-liquid separator 3, a power generation device 101, a retention tank 102, a return line L100, a return pump 103, an agent injection port 104, a first agent addition device 130, and a control device 140. In Figure 5, arrows indicate the flow of fluid.

[0145] In the geothermal power generation system 100, geothermal fluid extracted from the production well 2 is sent to the gas-liquid separator 3. The gas-liquid separator 3 separates geothermal water and geothermal steam from the geothermal fluid ejected from the production well 2. The geothermal water and geothermal steam separated in the gas-liquid separator 3 are sent via piping to the power generation device 101, which generates power using the geothermal water or geothermal steam separated in the gas-liquid separator 3 as a heat source. The geothermal water whose heat has been recovered in the power generation device 101 is introduced into the retention tank 102 via piping.

[0146] In the example shown in Figure 5, the geothermal steam separated in the gas-liquid separator 3 is sent to a flash power generation system 101a, which generates electricity using the geothermal steam separated in the gas-liquid separator 3 as a heat source, and the geothermal water separated in the gas-liquid separator 3 is sent to a binary power generation system 101b, which generates electricity using the geothermal water separated in the gas-liquid separator 3 as a heat source.

[0147] The power generation device 101 is not particularly limited, and may include a flash power generation device 101a and a binary power generation device 101b, or may include either the flash power generation device 101a or the binary power generation device 101b.

[0148] The flash power generation system 101a includes a turbine that rotates when supplied with geothermal steam separated in the gas-liquid separator 3, a generator connected to the turbine, a condenser that condenses the geothermal steam discharged from the turbine, a cooling tower that cools the condensed water condensed in the condenser, etc. The binary power generation system 101b includes a medium evaporator that evaporates a low-boiling-point heat medium through heat exchange, a turbine that rotates when supplied with the vaporized heat medium, a generator, a medium condenser, etc.

[0149] The retention tank 102 stores the geothermal water whose heat has been recovered by the power generation device 101. The geothermal water is retained until a polymerization reaction of silica in the geothermal water progresses and the silica-based insoluble components are sufficiently coagulated and precipitated.

[0150] The reinjection line L100 is a line that connects the outlet of the retention tank 102 to the reinjection well 4.

[0151] The reduction pump 103 is provided midway along the reduction line L100 and returns the geothermal water discharged from the retention tank 102 to the reduction well 4. The geothermal water discharged from the retention tank 102 is returned to the reduction well 4 via the reduction line L100 by the reduction pump 103.

[0152] The chemical injection port 104 is provided in the reduction line L100 between the retention tank 102 and the reduction pump 103.

[0153] The first chemical addition device 130 is a device that injects a chemical into a chemical injection port, and may include multiple chemical tanks 131a, 131b, and 131c that store chemicals, and multiple chemical injection pumps 132a, 132b, and 132c that are connected to the multiple chemical tanks 131a, 131b, and 131c, respectively, and that discharge the chemicals toward the chemical injection port 104. The number of chemical tanks 131a, 131b, and 131c is three in the example shown in FIG. 5 , but is not limited to this and may be selected depending on the number of chemical types used, and may be four or more. The number of chemical injection pumps 132a, 132b, and 132c can be selected depending on the number of chemical tanks 131a, 131b, and 131c.

[0154] The multiple chemical tanks 131a, 131b, and 131c may contain a tracer reagent, a cleaning agent, and a corrosive agent that is corrosive to the metals that make up the reduction line L100, respectively. For example, the chemical tank 131a contains a tracer reagent, the chemical tank 131b contains a cleaning agent, and the chemical tank 131c contains a corrosive agent. Hereinafter, in this specification, the chemical injection pump connected to the chemical tank 131a containing the tracer reagent may be referred to as the tracer reagent injection pump 132a, the chemical injection pump connected to the chemical tank 131b containing the cleaning agent may be referred to as the cleaning agent injection pump 132b, and the chemical injection pump connected to the chemical tank 131c containing the corrosive agent may be referred to as the corrosive agent injection pump 132c.

[0155] The tracer reagent is an agent used to confirm that the cleaning agent has reached the downstream side of the reduction line L100. Examples of tracer reagents include halogens such as iodine and bromine, radioactive isotopes such as iodine-131, bromine-82, and tritium, aromatic sulfonates such as sodium benzoate, sodium toluenesulfonate, sodium xylenesulfonate, sodium benzenesulfonate, 1-naphthalenesulfonic acid, and 1,5-naphthalenedisulfonic acid, fluorescent dyes such as sodium fluorescein, rhodamine WT, and 2,6,8-naphthylaminedisulfonic acid (amino G acid), and metal indicators. Among these, the tracer reagent is preferably an aromatic sulfonate.

[0156] The cleaning agent is a chemical agent for removing and cleaning scale adhering to the inside of the piping of the reduction line L100. The cleaning agent may be, for example, a chemical agent containing one or more selected from an acidic chemical agent, a basic chemical agent, a chelating agent, a hydrogen peroxide-based chemical agent, a dispersant, and a catalase-based chemical agent.

[0157] Acidic agents can be used to dissolve calcium-based scale, and examples of acidic agents include sulfuric acid, hydrochloric acid, acetic acid, and citric acid.

[0158] A basic agent can be used to dissolve silica-based scale (amorphous silica). Examples of basic agents include sodium hydroxide, potassium hydroxide, and ammonium salts.

[0159] Chelating agents can be used to mask dissolved metals in geothermal water under pH adjustment before using other cleaning agents, thereby preventing the waste of other cleaning agents. Examples of chelating agents include ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), hydroxyethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), trimethanolamine, and sodium gluconate.

[0160] Hydrogen peroxide-based agents can be used to dissolve the ooze, such as aqueous hydrogen peroxide.

[0161] The dispersant can be used to disperse and remove scale adhering to the inner wall of a pipe, etc. Examples of the dispersant include sodium polyacrylate and various surfactants.

[0162] The catalase-based agent can be used to decompose the hydrogen peroxide-based agent remaining in the geothermal water after the hydrogen peroxide-based agent has been used.

[0163] The corrosive agent is a chemical that is passed through the reduction line L100 after cleaning to elute metals constituting the piping of the reduction line L100, and the cleaning state is determined based on the concentration of the eluted metal ions. The corrosive agent may be, for example, one selected from sulfuric acid, hydrochloric acid, acetic acid, and citric acid.

[0164] The geothermal power generation system 100 may include a fourth pipe L104 connected to the chemical injection port 104 of the reduction line L100, and a fifth valve V105 provided midway along the fourth pipe L104 for opening and closing the flow path of the fourth pipe L104. The first chemical addition device 130 may also include a sixth pipe L106 branching from the fourth pipe L104 and connected to the outlet of the chemical injection pump 132a, a seventh pipe L107 branching from the fourth pipe L104 and connected to the outlet of the chemical injection pump 132b, and an eighth pipe L108 branching from the fourth pipe L104 and connected to the outlet of the chemical injection pump 132c.

[0165] Depending on the distance between the retention tank 102 and the reduction pump 103, etc., the geothermal power generation system 100 may include a temporary fifth pipe L105 that branches off from the fourth pipe L104 and extends to the inlet of the retention tank 102, as necessary. In this case, the chemical agent supplied from the first chemical addition device 130 is supplied to the reduction line L100 from the outlet of the retention tank 102 together with the geothermal water in the retention tank 102.

[0166] The geothermal power generation system 100 includes a branching section 110 that is provided midway along the reinjection line L100, downstream of the reinjection pump 103 and vertically above the reinjection well 4, and that branches the flow of geothermal water; a first liquid analyzer 111 that is connected vertically upward from the branching section 110; and a scale debris collector 113 that is connected horizontally from the branching section 110. The branching section 110 branches the flow of geothermal water in four directions and may be, for example, a four-way valve. The geothermal power generation system 100 may include a first valve (reinjection valve) V101 that is provided on the reinjection line L100 between the branching section 110 and the reinjection well 4 and that opens and closes the flow path between the branching section 110 and the reinjection well 4.

[0167] The first liquid analyzer 111 is connected to the third pipe L103 branching from the branching section 110. The first liquid analyzer 111 analyzes and detects components contained in the fluid. The first liquid analyzer 111 detects at least a tracer reagent. The first liquid analyzer 111 also measures pH, dielectric constant, or dissolved ion concentration. The first liquid analyzer 111 may be, for example, a high-performance liquid chromatograph.

[0168] The geothermal power generation system 100 may include a liquid delivery pump 112 provided midway along the third pipe L103 and discharging the fluid flowing through the reduction line L100 toward the inlet of the first liquid analyzer 111, and a fourth valve V104 provided in the third pipe L103 upstream of the liquid delivery pump 112 and opening and closing the flow path of the third pipe L103.

[0169] The scale debris collector 113 has a residue inlet 113a, a solvent inlet 113b, and a residue outlet 113c, and collects scale debris that flows through the return line L100 with a delay after cleaning of the return line L100 is completed. The geothermal power generation system 100 may include a first pipe L101 that connects the branching section 110 and the residue inlet 113a, and a second valve V102 that is provided in the first pipe L101 and opens and closes the flow path of the first pipe L101.

[0170] The geothermal power generation system 100 includes a dissolving agent addition device 150 that injects a dissolving agent into the dissolving agent inlet 113b of the scale fragment collector 113. The dissolving agent addition device 150 may include a dissolving agent tank 151 that stores the dissolving agent, and a dissolving agent injection pump 152 that is connected to the dissolving agent tank 151 and discharges the dissolving agent toward the dissolving agent inlet 113b. The dissolving agent is a chemical that dissolves the scale collected in the scale fragment collector 113, and may be, for example, one selected from a basic chemical, a fluoride-based chemical, and an acidic chemical.

[0171] The basic and acidic agents may be the same as those used in the cleaning agents described above. Examples of fluoride-based agents include hydrofluoric acid, hexafluorophosphoric acid, and ammonium fluoride.

[0172] The geothermal power generation system 100 may include a second pipe L102 that connects the solvent injection port 113b and the discharge port of the solvent injection pump 152, and a third valve V103 that is provided in the second pipe L102 and opens and closes the flow path of the second pipe L102.

[0173] Based on the analysis results of first liquid analyzer 111, control device 140 switches between injecting and stopping the drug by first drug addition device 130, and between injecting and stopping the dissolving agent by dissolving agent addition device 150. Specifically, based on the analysis results of first liquid analyzer 111, control device 140 controls multiple drug injection pumps 132a, 132b, 132c, dissolving agent injection pump 152, and first valve V101.

[0174] 6 is a time chart showing the cleaning operation in the geothermal power generation system according to the second embodiment. The control device 140 may execute the cleaning operation by causing the first chemical addition device 130 to supply the cleaning agent and simultaneously supplying the tracer reagent two or more times at intervals of five minutes or more, and then stopping the supply of the cleaning agent and closing the first valve (reducing valve) V101 after the first liquid analyzer 111 detects the tracer reagent the same number of times as the number of times the tracer reagent was supplied.

[0175] As shown in FIG. 6 , at time t0, the control device 140, with the first valve (reducing valve) V101 open, sends a command to the tracer reagent injection pump 132a to discharge the tracer reagent at least twice with an interval of at least five minutes between each supply, and sends a command to the cleaning agent injection pump 132b to continuously discharge the tracer reagent. After receiving a signal from the first liquid analyzer 111 indicating that the tracer reagent has been detected the same number of times as the supply, the control device 140 sends a command to the cleaning agent injection pump 132b to stop discharging the tracer reagent at time t1, and simultaneously sends a command to the first valve V101 to close the tracer reagent injection pump 132b. By receiving the signal indicating that the tracer reagent has been detected the same number of times as the supply, the control device 140 can confirm that the cleaning agent has reached the downstream side of the reducing line L100. Time T1 is the time required for the cleaning agent to reach the downstream side of the reducing line L100.

[0176] The control device 140 opens the first valve (reduction valve) V101 two to three hours after the first valve V101 is closed, and while the first valve V101 is open, causes the first chemical addition device 130 to supply a corrosive agent, and then determines the cleaning state based on the concentration of metal ions detected by the first liquid analyzer 111.

[0177] At time t2, two to three hours (time T2) after time t1, when the cleaning agent injection pump 132b stops and the first valve (reduction valve) V101 closes, the control device 140 simultaneously sends a command to the corrosive agent injection pump 132c to discharge and a command to the first valve V101 to open. Time T2 is the time required for the cleaning agent to be in sufficient contact with the inner wall of the piping of the reduction line L100. Then, after receiving the measured value of the metal ion concentration from the first liquid analyzer 111, the control device 140 determines the cleaning state at time t3, after time T3 has elapsed. Time T3 is the time required to confirm the cleaning state.

[0178] As cleaning progresses, the inner wall of the pipe becomes more exposed and the metal constituting the pipe dissolves into the fluid, increasing the concentration of metal ions contained in the fluid. The concentration of metal ions detected by the first liquid analyzer 111 may be the concentration of iron ions. For example, the control device 140 may determine that cleaning is complete when the concentration of iron ions reaches 100 ppm. The analysis result obtained by the first liquid analyzer 111 may be a dielectric constant.

[0179] If the concentration of metal ions detected by the first liquid analyzer 111 is less than the specified value, the control device 140 determines that cleaning is not complete and performs the cleaning operation again from time T1 to T3, repeating the cleaning operation from time T1 to T3 until the concentration of metal ions detected by the first liquid analyzer 111 reaches the specified value. Time T4 is the time for repeating the cleaning operation from time T1 to T3. The time chart showing the cleaning operation at time T4 is the same as that for times T1 to T3, and is therefore omitted from FIG. 6.

[0180] When the concentration of metal ions detected by the first liquid analyzer 111 reaches a specified value, the control device 140 determines that cleaning is complete at time t5, terminates the cleaning operation, and returns to normal operation. The time T5 from time t4 to time t5 is the final time of the time T3 for checking the cleaning state multiple times.

[0181] When the control device 140 determines that the concentration of metal ions detected by the first liquid analyzer 111 has reached a specified value and cleaning is complete, the control device 140 causes geothermal water to flow into the residue inlet 113a, causes the scale collector 113 to collect the scale, and then causes the solubilizing agent adding device 150 to inject a solubilizing agent into the solubilizing agent inlet 113b and closes the second valve V102 and the third valve V103. Specifically, when the control device 140 determines that the concentration of metal ions detected by the first liquid analyzer 111 has reached a specified value and cleaning is complete, it preferably first controls the control device 140 to open the second valve V102 and allow geothermal water to flow into the residue inlet 113a for one week or more. This allows the geothermal power generation system 100 to sufficiently collect the scale that flows through the reduction line L100 with a delay after cleaning in the scale collector 113. Next, the control device 140 injects a dissolving agent into the dissolving agent inlet 113b using the dissolving agent adding device 150, and if the dissolving agent is a basic chemical, closes the second valve V102 and the third valve V103 when the pH of the fluid in the scale debris collector 113 reaches a specified value. The pH of the fluid in the scale debris collector 113 can be detected, for example, by a pH meter (not shown) provided in the scale debris collector 113, and the control device 140 receives the measured pH value from the pH meter.

[0182] The scale fragment collector 113 is maintained at a high temperature by the sensible heat of the reinjection well 4, which improves the effect of the dissolving agent in the scale fragment collector 113 and promotes the dissolution of the scale fragments. From the viewpoint of promoting the dissolution of the scale fragments, it is preferable to position the scale fragment collector 113 so that the temperature inside the scale fragment collector 113 is maintained at 80°C or higher.

[0183] The control device 140 closes the second valve V102 and the third valve V103, leaves them as they are for 48 hours or more, and then opens the second valve V102, thereby controlling the sending of the fluid containing the dissolved scale particles in the scale particle collector 113 to the reinjection well 4 via the second pipe L102. Specifically, the control device 140 applies pressure to the inside of the scale particle collector 113 using a pressure device (not shown), thereby pushing back the geothermal water flowing in from the residue inlet 113a via the opened second valve V102, and controls the sending of the fluid containing the dissolved scale particles in the scale particle collector 113 to the reinjection well 4 via the second pipe L102.

[0184] The control device 140 then controls the discharge of scale particles, rock fragments, iron rust, etc. remaining in the scale particle collector 113 to the outside through the residue discharge port 113c.

[0185] The control device 140 may further control the reduction pump 103, the liquid feed pump 112, the fourth valve V104, the fifth valve V105, and the sixth valve V106.

[0186] Next, the configuration for recovering chemicals in the geothermal power generation system 100 will be described. FIG. 7 is a schematic diagram of the chemical recovery line L130 in the geothermal power generation system 100 according to the second embodiment. As shown in FIG. 7 , the geothermal power generation system 100 includes a chemical recovery line L130 that branches off from a pipe connecting the dissolving agent injection port 113b and the dissolving agent addition device 150 and is connected to a pipe connecting the branch section 110 and the reinjection well 4. Also, as shown in FIG. 7 , the geothermal power generation system 100 includes, in order from upstream to downstream, a waste liquid recovery section 61, a scale separation section 62, a first chemical recovery section 63, an impurity separation section 64, a second chemical recovery section 65, a chemical purification section 66, and a regenerated chemical tank 69, as well as a waste liquid adjustment device 67. The waste liquid adjustment device 67 is connected to the scale separation section 62, the impurity separation section 64, and the chemical purification section 66.

[0187] The chemical recovery line L130 may include a first chemical recovery line L130a connecting the waste liquid recovery section 61, the scale separation section 62, the first chemical recovery section 63, the impurity separation section 64, the second chemical recovery section 65, the chemical purification section 66, and the regenerated chemical tank 69, and a second chemical recovery line L130b branching from the first chemical recovery line L130a between the chemical purification section 66 and the regenerated chemical tank 69. The chemical recovery line L130 may also include a third chemical recovery line L130c branching from the second chemical recovery line L130b and connecting to the scale separation section 62, a fourth chemical recovery line L130d branching from the second chemical recovery line L130b and connecting to the impurity separation section 64, and a fifth chemical recovery line L130e branching from the second chemical recovery line L130b and connecting to the chemical purification section 66.

[0188] The waste liquid that has passed through the scale debris collector 113 flows into the chemical recovery line L130 and is purified as it passes through the waste liquid recovery section 61, scale separation section 62, first chemical recovery section 63, impurity separation section 64, second chemical recovery section 65, and chemical purification section 66, and the regenerated chemical purified from the waste liquid is stored in the regenerated chemical tank 69. In addition, impurities and the like generated in the process of refining the waste liquid into the regenerated chemical are adjusted and then returned to the reinjection well 4 from the second chemical recovery line L130b via the third chemical recovery line L130c, fourth chemical recovery line L130d, and fifth chemical recovery line L130e.

[0189] The geothermal power generation system 100 may include a heat exchanger 80 that exchanges heat between the waste liquid in the waste liquid recovery section 61 and the refrigerant, and a heat pump 81 that supplies the heat recovered by the heat exchanger 80 to the scale chip collector 113. The configuration for recovering the chemical agent in the geothermal power generation system 100 differs from the configuration for recovering the chemical agent in the geothermal power generation system 1 of the first embodiment in that the geothermal power generation system 100 may include the heat exchanger 80 and the heat pump 81. The configuration for recovering the chemical agent in the geothermal power generation system 100 other than the heat exchanger 80 and the heat pump 81 is the same as the configuration for recovering the chemical agent in the geothermal power generation system 1 of the first embodiment, and therefore a description thereof will be omitted.

[0190] The heat exchanger 80 may be connected to the waste liquid recovery section 61 or to the impurity separation section 64. The heat exchanger 80 may be connected to the chemical recovery line L130 between the waste liquid recovery section 61 and the scale separation section 62, the chemical recovery line L130 between the scale separation section 62 and the first chemical recovery section 63, the chemical recovery line L130 between the first chemical recovery section 63 and the impurity separation section 64, or the chemical recovery line L130 between the impurity separation section 64 and the second chemical recovery section 65.

[0191] The geothermal power generation system 100 comprises a gas-liquid separator 3, a power generation device 101, a retention tank 102, a reduction line L100, a reduction pump 103, a chemical injection port 104 provided in the reduction line L100 between the retention tank 102 and the reduction pump 103, and a first chemical addition device 130. The geothermal power generation system 100 also includes a branching section 110, a first liquid analyzer 111, a scale fragment collector 113 having a residue inlet 113a, a dissolving agent inlet 113b, and a residue outlet 113c, a dissolving agent addition device 150, a control device 140 that switches between the injection operation and the stop of injection of chemicals by the first chemical addition device 130, and switches between the injection operation and the stop of injection of chemicals by the dissolving agent addition device 150 based on the analysis results of the first liquid analyzer 111, a chemical recovery line L130, a waste liquid recovery section 61, a scale separation section 62, a first chemical recovery section 63, an impurity separation section 64, a second chemical recovery section 65, a chemical purification section 66, a regenerated chemical tank 69, and a waste liquid adjustment device 67, and the waste liquid adjustment device 67 is connected to the scale separation section 62, the impurity separation section 64, and the chemical purification section 66.

[0192] With this configuration, the control device 140 confirms the arrival of the chemical agent based on the analysis results of the first liquid analyzer 111 provided downstream of the return line L100 and switches between injecting and stopping the chemical agent using the first chemical agent adding device 130. Therefore, the geothermal power generation system 100 can distribute the chemical agent throughout the entire return line L100 from the upstream side to the downstream side and clean the return line L100 without opening or disassembling the geothermal power generation system 100. Furthermore, even if scale particles flow through the return line L100 after cleaning the geothermal power generation system 100, the scale particles are collected using the scale particle collector 113, and the control device 140 switches between injecting and stopping the dissolving agent using the dissolving agent adding device 150. Therefore, the geothermal power generation system 100 can dissolve and remove scale particles flowing through the return line L100 after cleaning without opening or disassembling the geothermal power generation system 100. As a result, the geothermal power generation system 100 can sufficiently remove scale from the reduction line L100.

[0193] Furthermore, the waste liquid after cleaning the return line L100 is adjusted by the waste liquid adjustment device 67 in the waste liquid recovery section 61, scale separation section 62, first chemical recovery section 63, impurity separation section 64, second chemical recovery section 65, and chemical purification section 66, where scale-containing substances and impurities are separated and removed in order, and the waste liquid is purified. Thus, the geothermal power generation system 1 can obtain a purified regenerating chemical from the waste liquid, and the regenerating chemical is stored in the regenerating chemical tank 69. As described above, the geothermal power generation system 100 can sufficiently remove scale and recover the chemical used for cleaning.

[0194] The geothermal power generation system 100 includes a heat exchanger 80 and a heat pump 81 that supplies heat recovered by the heat exchanger 80 to a scale debris collector 113. With this configuration, when the scale separation section 62 lowers the temperature of the fluid to precipitate silica scale and separates the silica scale, the exhaust heat generated by lowering the temperature of the fluid can be used as heat to promote the dissolution of the scale debris in the scale debris collector 113.

[0195] Specifically, geothermal power generation system 100 includes first valve V101, first chemical addition device 130 includes multiple chemical tanks 131a, 131b, and 131c and multiple chemical injection pumps 132a, 132b, and 132c, and dissolving agent addition device 150 includes dissolving agent tank 151 and dissolving agent injection pump 152. Furthermore, control device 140 controls multiple chemical injection pumps 132a, 132b, and 132c, dissolving agent injection pump 152, and first valve V101 based on the analysis results of first liquid analyzer 111.

[0196] With this configuration, the control device 140 selects a chemical appropriate for the purpose from among multiple chemicals based on the analysis results of the first liquid analyzer 111 and controls the chemical injection pump that discharges the selected chemical, thereby allowing the geothermal power generation system 100 to supply the chemical appropriate for the purpose to the return line L100. After the control device 140 distributes the chemical throughout the return line L100, the control device 140 closes the first valve V101, allowing the geothermal power generation system 100 to thoroughly contact the chemical with the inner wall of the return line L100 piping and enhance the cleaning effect. Furthermore, the control device 140 controls the solvent injection pump 152 based on the analysis results of the first liquid analyzer 111, allowing the geothermal power generation system 100 to thoroughly dissolve and remove scale particles circulating through the return line L100 after cleaning. As a result, the geothermal power generation system 100 can more thoroughly remove scale from the return line L100.

[0197] In the geothermal power generation system 100, multiple chemical tanks 131a, 131b, and 131c contain a tracer reagent, a cleaning agent, and a corrosive agent that is corrosive to the metals that make up the return line L100. By simultaneously supplying the tracer reagent and the cleaning agent to the return line L100, the geothermal power generation system 100 can confirm the arrival of the cleaning agent using the first liquid analyzer 111, and can spread the cleaning agent throughout the return line L100 from the upstream to downstream sides, thereby cleaning the return line L100. Furthermore, by supplying the corrosive agent to the return line L100, the geothermal power generation system 100 can dissolve metals that make up the piping of the return line L100 and determine the cleaning state based on the concentration of the eluted metal ions. Therefore, the geothermal power generation system 100 can more thoroughly remove scale from the return line L100.

[0198] In the geothermal power generation system 100, the tracer reagent is preferably an aromatic sulfonate. In the geothermal power generation system 100, by supplying the aromatic sulfonate as the tracer reagent to the reduction line L100 simultaneously with the cleaning agent, the tracer reagent can be easily detected by the first liquid analyzer 111, and the arrival of the cleaning agent can be easily confirmed.

[0199] In the geothermal power generation system 100, the cleaning agent includes one or more selected from an acidic agent, a basic agent, a chelating agent, a hydrogen peroxide-based agent, a dispersant, and a catalase-based agent. This allows the geothermal power generation system 100 to supply to the reduction line L100 the cleaning agent that is optimal for each of the soft mud, calcium carbonate, amorphous silica, iron rust, and the like contained in the scale.

[0200] In the geothermal power generation system 100, the corrosive agent is one selected from sulfuric acid, hydrochloric acid, acetic acid, and citric acid. The geothermal power generation system 100 supplies one selected from sulfuric acid, hydrochloric acid, acetic acid, and citric acid as the corrosive agent to the reduction line L100, thereby eluting iron constituting the piping of the reduction line L100, and the cleaning state can be determined based on the concentration of the eluted iron ions.

[0201] In the geothermal power generation system 100, the dissolving agent is one selected from a basic agent, a fluoride-based agent, and an acidic agent, thereby enabling the geothermal power generation system 100 to supply the scale fragment collector 113 with the most suitable dissolving agent for each of calcium carbonate, amorphous silica, and the like contained in the scale.

[0202] In the geothermal power generation system 100, the control device 140 causes the first chemical addition device 130 to supply the cleaning agent and at the same time supply the tracer reagent two or more times with an interval of five minutes or more between each supply, and after the first liquid analyzer 111 detects the tracer reagent the same number of times as the number of supplies, stops the supply of the cleaning agent and closes the first valve V101, thereby performing the cleaning operation.

[0203] As a result, the control device 140 confirms the arrival of the cleaning agent using the first liquid analyzer 111, and after the cleaning agent has spread throughout the entire return line L100, closes the first valve V101, allowing the geothermal power generation system 100 to bring the cleaning agent into sufficient contact with the inner wall of the piping of the return line L100, thereby improving the cleaning effect. Thus, the geothermal power generation system 100 can more sufficiently remove scale from the return line L100.

[0204] In the geothermal power generation system 100, the control device 140 opens the first valve V101 two to three hours after the first valve V101 is closed, causes the first chemical agent addition device 130 to supply a corrosive agent, and then determines the cleaning state based on the concentration of metal ions detected by the first liquid analyzer 111. This allows the geothermal power generation system 100 to clean the return line L100 according to the cleaning state, and more sufficiently removes scale from the return line L100.

[0205] In the geothermal power generation system 100, if the concentration of metal ions detected by the first liquid analyzer 111 is less than a specified value, the control device 140 determines that cleaning is not complete and performs the cleaning operation again, repeating the cleaning operation until the concentration of metal ions detected by the first liquid analyzer 111 reaches the specified value. This allows the geothermal power generation system 100 to prevent poor cleaning of the return line L100 and more thoroughly remove scale from the return line L100.

[0206] The geothermal power generation system 100 includes a second valve V102 and a third valve V103. When the control device 140 determines that the metal ion concentration detected by the first liquid analyzer 111 has reached a specified value and cleaning is complete, the control device 140 causes geothermal water to flow into the residue inlet 113a, causes the scale collector 113 to collect scale, and then causes the dissolving agent adding device 150 to inject a dissolving agent into the dissolving agent inlet 113b, and closes the second valve V102 and the third valve V103. As a result, when scale flows through the return line L100 after cleaning of the return line L100 is completed, the geothermal power generation system 100 can collect, dissolve, and remove the scale using the scale collector 113. Therefore, the geothermal power generation system 100 can sufficiently remove scale from the return line L100.

[0207] In the geothermal power generation system 100, the control device 140 closes the second valve V102 and the third valve V103, leaves them open for 48 hours or more, and then opens the second valve V102, thereby controlling the sending of a fluid containing dissolved scale particles in the scale particle collector to the reinjection well 4 via the second pipe L102. The control device 140 immerses the scale particles collected in the scale particle collector 113 in a dissolving agent in an environment maintained at a high temperature by receiving sensible heat from the reinjection well 4, thereby allowing the geothermal power generation system 100 to thoroughly dissolve and remove the scale particles. Thus, the geothermal power generation system 100 can more thoroughly remove scale from the reinjection line L100.

[0208] In the geothermal power generation system 100, the control device 140 controls the discharge of scale particles remaining in the scale particle collector 113 to the outside through the residue discharge port 113c, thereby enabling the control device 140 to remove the sparingly soluble scale particles that could not be dissolved by the solvent in the scale particle collector 113.

[0209] Third Embodiment A geothermal power generation system 100 according to a third embodiment will be described. The geothermal power generation system 100 according to the third embodiment cleans the reduction line L100 during normal operation (during power generation). First, the configuration for cleaning in the geothermal power generation system 100 will be described.

[0210] FIG. 8 is a schematic diagram showing a geothermal power generation system according to a third embodiment, and FIG. 9 is an enlarged view of a main portion of FIG. 8 . In FIGS. 8 and 9 , arrows indicate fluid flow. As shown in FIGS. 8 and 9 , the geothermal power generation system 100 may include a first bypass pipe L121 branching from the return line L100 downstream of the return pump 103 and connected to the return line L100, and a second bypass pipe L122 branching from the return line L100 downstream of the first bypass pipe L121 and connected to the return line L100. The geothermal power generation system 100 may also include a first switching valve V121 provided in the return line L100 and capable of switching the flow path of the return line L100 to the first bypass pipe L121, and a second switching valve V122 provided in the return line L100 and capable of switching the flow path of the return line L100 to the second bypass pipe L122.

[0211] Furthermore, as shown in Figure 9, the geothermal power generation system 100 may be equipped with a chemical adjustment section 115 provided in the first bypass piping L121, a first gate valve V123 provided in the first bypass piping L121 upstream of the chemical adjustment section 115, a second gate valve V124 provided in the first bypass piping L121 downstream of the chemical adjustment section 115, a second chemical addition device 170, and an air introduction device 116.

[0212] The drug adjustment section 115 is the first bypass pipe L121 between the first gate valve V123 and the second gate valve V124, and is a part for introducing air into the drug in the drug adjustment section 115 and adjusting the drug to be supplied to the return line L100.

[0213] The second chemical addition device 170 injects a chemical into the chemical preparation unit 115. The second chemical addition device 170 may include a chemical tank 171 that stores the chemical, and a chemical injection pump 172 that is connected to the chemical tank 171 and ejects the chemical toward the chemical preparation unit 115. While the number of chemical tanks 171 is one in the example shown in FIG. 9 , this is not limited to one, and may be selected according to the number of chemical types used, and may be multiple. The number of chemical injection pumps 172 may be selected according to the number of chemical tanks 171.

[0214] The chemical stored in the chemical tank 171 may be a cleaning agent, or a cleaning agent and a corrosive agent that is corrosive to the metal that constitutes the reduction line L100. There may be multiple chemical tanks 171, and when the chemical is a cleaning agent and a corrosive agent, the cleaning agent and the corrosive agent are stored in separate chemical tanks 171.

[0215] The cleaning agent is a chemical agent for removing and cleaning scale adhering to the inside of the piping of the reduction line L100. As the cleaning agent, the same cleaning agent as that used in the geothermal power generation system 1 of the first embodiment shown in FIG. 1 can be used.

[0216] The corrosive agent is a chemical that is passed through the reduction line L100 after cleaning to dissolve metals that constitute the piping of the reduction line L100, and the cleaning state is determined based on the concentration of the dissolved metal ions. As the corrosive agent, the same corrosive agent as in the embodiment shown in FIG. 1 can be used.

[0217] The air introduction device 116 supplies air to the chemical in the chemical preparation unit 115. Examples of the air introduction device 116 include an air compressor and a blower. The geothermal power generation system 100 may include an air filter 117 provided upstream of the air introduction device 116 and a drainage pump 118 that drains the geothermal water in the chemical preparation unit 115.

[0218] The geothermal power generation system 100 may include a ninth pipe L123 connected to the chemical preparation unit 115, a tenth pipe L124 branching from the ninth pipe L123 and connected to the first bypass pipe L121 downstream of the second gate valve V124, an eleventh pipe L125 branching from the ninth pipe L123 and connected to the outlet of the air introduction device 116, and a twelfth pipe L126 branching from the eleventh pipe L125 and connected to the outlet of the chemical injection pump 172. The drainage pump 118 is provided in the tenth pipe L124.

[0219] The ninth pipe L123 extends vertically downward from the chemical preparation unit 115. The ninth pipe L123 sends geothermal water discharged from the chemical preparation unit 115 to the tenth pipe L124, and also sends a cleaning agent and air to the chemical preparation unit 115. The geothermal power generation system 100 may include a thirteenth pipe L127 connected to the chemical preparation unit 115 and extending vertically upward from the chemical preparation unit 115. The thirteenth pipe L127 exhausts air from the chemical preparation unit 115 to the outside and introduces air into the chemical preparation unit 115. The geothermal power generation system 100 may include a fifteenth valve V130 provided midway along the thirteenth pipe L127 and opening and closing the flow path of the thirteenth pipe L127.

[0220] The geothermal power generation system 100 may include a seventh valve V125 provided midway along the ninth pipe L123 and opening and closing the flow path of the ninth pipe L123, an eighth valve V126 provided downstream of the drainage pump 118 in the tenth pipe L124 and opening and closing the flow path of the tenth pipe L124, a ninth valve V127 provided midway along the eleventh pipe L125 and opening and closing the flow path in the eleventh pipe L125 downstream of the branch point to the twelfth pipe L126, a tenth valve V129 that opens and closes the flow path upstream of the branch point to the twelfth pipe L126, and an eleventh valve V128 provided downstream of the chemical injection pump 172 in the twelfth pipe L126 and opening and closing the flow path of the twelfth pipe L126.

[0221] The geothermal power generation system 100 may include a chemical collector 120 provided in the second bypass pipe L122, a third gate valve V131 provided in the second bypass pipe L122 upstream of the chemical collector 120, a fourth gate valve V132 provided in the second bypass pipe L122 downstream of the chemical collector 120, and a second liquid analyzer 121 connected to the chemical collector 120.

[0222] The chemical collector 120 is a part for collecting waste liquid containing the chemical after cleaning. The second liquid analyzer 121 may be any device capable of detecting air introduced into the chemical, such as an ultrasonic flowmeter, a pressure gauge, a thermometer, or an air bubble sensor. The second liquid analyzer 121 may further measure pH, dielectric constant, or dissolved ion concentration.

[0223] The geothermal power generation system 100 may include a fourteenth pipe L128 connected to the chemical collecting unit 120 and extending vertically upward, and a fifteenth pipe L129 connected to the chemical collecting unit 120 and extending vertically downward. The fourteenth pipe L128 discharges air separated in the chemical collecting unit 120 to the outside. The geothermal power generation system 100 may include an air vent valve V133 provided midway along the fourteenth pipe L128. The air vent valve V133 automatically discharges air accumulated in the chemical collecting unit 120. The fifteenth pipe L129 connects the chemical collecting unit 120 to the second liquid analyzer 121 and sends the fluid in the chemical collecting unit 120 to the second liquid analyzer 121. The geothermal power generation system 100 may include a liquid delivery pump 122 that is provided midway along the 15th pipe L129 and discharges the fluid flowing through the 15th pipe L129 toward the inlet of the second liquid analyzer 121, and a 12th valve V134 that is provided on the 15th pipe L129 upstream of the liquid delivery pump 122 and opens and closes the flow path of the 15th pipe L129.

[0224] The geothermal power generation system 100 may further include a chemical recovery line L130 branching from the second bypass piping and connected to a piping connecting the branch section 110 and the reinjection well 4. Similarly to the example shown in FIG. 7 , the geothermal power generation system 100 may include, in order from upstream, a waste liquid recovery section 61, a scale separation section 62, a first chemical recovery section 63, an impurity separation section 64, a second chemical recovery section 65, a chemical purification section 66, and a regenerated chemical tank 69, as well as a waste liquid adjustment device 67, along the chemical recovery line L130. The waste liquid adjustment device 67 is connected to the scale separation section 62, the impurity separation section 64, and the chemical purification section 66. The configuration for recovering chemicals in the geothermal power generation system 100 of the third embodiment includes all of the configuration for recovering chemicals in the geothermal power generation system 100 of the second embodiment, and therefore a description of the common configuration will be omitted. Hereinafter, only the differences between the configuration for recovering the agent in the geothermal power generation system 100 of the second embodiment will be described.

[0225] As shown in Figure 9, the geothermal power generation system 100 may be equipped with a chemical recovery valve V135 located upstream of the waste liquid recovery section 61, midway along the chemical recovery line L130 branching off from the second bypass pipe L122, for opening and closing the flow path between the chemical collection section 120 and the waste liquid recovery section 61, and a thirteenth valve V136 located midway along the chemical recovery line L130, at the most downstream position of the chemical recovery line L130.

[0226] The geothermal power generation system 100 may include a 16th pipe L131 branching from the 12th pipe L126, and the regenerative agent tank 69 may be connected to the 16th pipe L131. The geothermal power generation system 100 may include a regenerative agent injection pump 123 that is provided midway along the 16th pipe L131 and discharges the regenerative agent, and a 14th valve V137 that is provided midway along the 16th pipe L131 downstream of the regenerative agent injection pump 123 and opens and closes the flow path of the 16th pipe L131.

[0227] The control device 140 may switch between injecting and stopping the chemical by the second chemical addition device 170 and between introducing and stopping the air by the air introduction device 116 based on the analysis results of the second liquid analyzer 121, and may also control the first switching valve V121, the second switching valve V122, and the first to fourth gate valves V123, V124, V131, and V132. The control device 140 may also control the regenerated chemical injection pump 123, the fourteenth valve V137, the chemical recovery valve V135, and the thirteenth valve V136.

[0228] Next, a detailed description will be given of the cleaning operation in another example of the geothermal power generation system 100 according to the third embodiment. Figures 10A to 10E are enlarged views of the main parts of Figure 8 for explaining the cleaning operation in another example of the geothermal power generation system 100 according to the third embodiment. In Figures 10A to 10E, open valves are shown in white, closed valves are shown in black, and arrows indicate the flow of fluid.

[0229] The control device 140 may repeat normal operation, a drainage operation to discharge the geothermal water in the chemical preparation unit 115 after the normal operation, a chemical injection operation to inject chemicals into the chemical preparation unit 115 from which the geothermal water has been discharged, an air introduction operation to introduce air into the chemicals injected into the chemical preparation unit 115, a cleaning operation to switch the flow path of the reduction line L100 to the first bypass pipe L121 and the second bypass pipe L122 to perform cleaning, and a chemical recovery operation to circulate the waste liquid in the second bypass pipe to the chemical recovery line L130 after the line switching operation to recover the chemicals.

[0230] 10A, in normal operation, the control device 140 opens the first selector valve V121 and the second selector valve V122 and closes the first to fourth gate valves V123, V124, V131, and V132. In normal operation, the geothermal water flows through the reduction line L100, but does not flow through the first bypass pipe L121 or the second bypass pipe L122.

[0231] 10B , in a drainage operation to drain the geothermal water from the chemical preparation unit 115, the control device 140 opens the seventh valve V125 and the eighth valve V126 and operates the drain pump 118 to drain the geothermal water accumulated in the chemical preparation unit 115 and send it via the ninth pipe L123 and the tenth pipe L124 to the first bypass pipe L121 downstream of the second gate valve V124. At this time, the control device 140 opens the fifteenth valve V130, thereby draining the geothermal water accumulated in the chemical preparation unit 115 and introducing air into the chemical preparation unit 115 via the thirteenth pipe L127.

[0232] Next, as shown in FIG. 10C , in the chemical injection operation for injecting a chemical into the chemical preparation unit 115, the control device 140 closes the eighth valve V126, opens the seventh valve V125, the ninth valve V127, and the eleventh valve V128, operates the chemical injection pump 172, and starts the chemical injection operation by the second chemical addition device 170. At this time, the chemical is injected into the chemical preparation unit 115, and air inside the chemical preparation unit 115 is discharged to the outside via the thirteenth pipe L127. At the same time, in the chemical injection operation for injecting a chemical into the chemical preparation unit 115, the control device 140 opens the fourteenth valve V137, operates the regenerated chemical injection pump 123, and starts the injection operation of the regenerated chemical stored in the regenerated chemical tank 69.

[0233] Next, as shown in FIG. 10D, in a line switching operation in which the flow path of the reduction line L100 is switched to the first bypass pipe L121 and the second bypass pipe L122 to start cleaning, the control device 140 opens the first to fourth gate valves V123, V124, V131, and V132, switches the flow path of the reduction line L100 to the first bypass pipe L121 and the second bypass pipe L122, and controls the drug in the drug preparation unit 115 to circulate to the reduction line L100 and the second bypass pipe L122.

[0234] Then, in the air introduction operation for introducing air into the medicine, the control device 140 closes the eleventh valve V128, the fourteenth valve V137, and the fifteenth valve V130, and opens the seventh valve V125, the ninth valve V127, and the tenth valve V129. The control device 140 also stops the medicine injection pump 172 to stop the injection of the medicine by the second medicine addition device 170, and activates the air introduction device 116 to supply air to the medicine in the medicine preparation unit 115 via the ninth pipe L123 and the eleventh pipe L125.

[0235] Next, as shown in FIG. 10E , during the chemical recovery operation, the control device 140 causes the second liquid analyzer 121 to detect the concentration of air contained in the waste liquid in the chemical collector 120. When the detected concentration reaches a predetermined value, the control device 140 closes the third gate valve V131 and the fourth gate valve V132, opens the chemical recovery valve V135, and allows the waste liquid to flow through the chemical recovery line L130. By detecting air using the second liquid analyzer 121, the geothermal power generation system 100 can confirm that the chemical has reached the second bypass pipe L122. Furthermore, during the chemical recovery operation, the control device 140 opens the first selector valve V121 and the second selector valve V122.

[0236] When the air introduced into the chemical agent in the chemical agent preparation unit 115 accumulates in the chemical agent collection unit 120 to a predetermined level or more, it is discharged to the outside via the air vent valve V133 and the 14th pipe L128. The geothermal power generation system 100 may also include a degassing device (not shown) installed along the chemical agent recovery line L130. Examples of degassing devices include an ultrasonic degassing device, a vacuum decompression degassing device, and a centrifugal degassing device. Even if the air accumulated in the chemical agent collection unit 120 cannot be completely discharged to the outside via the air vent valve V133 and the 14th pipe L128, the geothermal power generation system 100 can sufficiently separate the air from the wastewater and return the degassed geothermal water to the reinjection well 4 via the chemical agent recovery line L130. Therefore, the geothermal power generation system 100 can maintain the permeability of the geothermal water returned to the reinjection well 4.

[0237] After the line switching operation, the control device 140 repeats the normal operation, the drainage operation, the chemical injection operation, the air introduction operation, the line switching operation, and the chemical recovery operation again after a predetermined time has elapsed.

[0238] After performing the cleaning operation, the control device 140 may close the first selector valve V121 and the second selector valve V122 and open the first to fourth gate valves V123, V124, V131, and V132. After stopping the injection of chemicals by the second chemical addition device 170 and supplying a corrosive agent by the second chemical addition device 170, the control device 140 may determine the cleaning state based on the concentration of metal ions detected by the second liquid analyzer 121. The concentration of metal ions detected by the second liquid analyzer 121 may be the concentration of iron ions. For example, the control device 140 may determine that cleaning is complete when the concentration of iron ions reaches 100 ppm. The analysis result by the second liquid analyzer 121 may be a dielectric constant.

[0239] If the concentration of metal ions detected by the second liquid analyzer 121 is less than a specified value, the control device 140 determines that cleaning is not complete and may repeat normal operation, drainage operation, chemical injection operation, air introduction operation, and cleaning operation again.

[0240] When the concentration of metal ions detected by the second liquid analyzer 121 reaches a specified value, the control device 140 determines that cleaning is complete, performs normal operation, and terminates the subsequent chemical injection operation, air introduction operation, and cleaning operation.

[0241] 11 is a time chart showing the cleaning operation in the geothermal power generation system 100 according to the third embodiment. Time t0 is the start time of the chemical injection operation in which the chemical is injected into the chemical preparation unit 115. At time t0, the control device 140 operates the chemical injection pump 172 with the first switching valve V121 and the second switching valve V122 open to start the chemical injection operation by the second chemical addition device 170, and simultaneously operates the regenerated chemical injection pump 123 to start the injection operation of the regenerated chemical stored in the regenerated chemical tank 69. Time T1 is the time required for the chemical injection operation in which the chemical and regenerated chemical are injected into the chemical preparation unit 115.

[0242] After the chemical injection operation, at time t1, the control device 140 gradually closes the first switching valve V121 and the second switching valve V122 and gradually opens the third gate valve V131 and the fourth gate valve V132. Time T2 is the time for the line switching operation to switch the flow path of the reduction line L100 to the first bypass pipe L121 and the second bypass pipe L122 and start cleaning.

[0243] Time t2 is the start time of the air introduction operation for introducing air into the medicine. At time t2, the control device 140 activates the air introduction device 116. This starts cleaning the return line L100. Time T3 is the time for the air introduction operation and the time for cleaning the return line L1000.

[0244] The control device 140 causes the second liquid analyzer 121 to detect the concentration of air contained in the waste liquid in the drug collection unit 120, and when the detected concentration reaches a specified value, stops the air introduction device 116 at time t3. At the same time, the control device 140 opens the drug collection valve V135 and gradually opens the first switching valve V121 and the second switching valve V122. If the amount of air accumulated in the drug collection unit 120 reaches or exceeds a specified value, the air vent valve V133 automatically opens, and the air is discharged to the outside via the fourteenth pipe L128. Time T4 is the time required for the drug collection operation to collect the drug.

[0245] The control device 140 executes normal operation at time t4 when the cleaning is completed. Time T4 is the time for normal operation.

[0246] The geothermal power generation system 100 includes a first bypass pipe L121, a second bypass pipe L122, a first switching valve V121, a second switching valve V122, a chemical preparation section 115, a first gate valve V123, a second gate valve V124, a second chemical addition device 170, an air introduction device 116, a chemical collection section 120, a third gate valve V131, a fourth gate valve V132, a second liquid analyzer 121, a chemical recovery line L130, a waste liquid recovery section 61, a scale separation section 62, a first chemical recovery section 63, an impurity separation section 64, a second chemical recovery section 65, a chemical purification section 66, a regenerated chemical tank 69, and a waste liquid adjustment device 67, and the waste liquid adjustment device 67 is connected to the scale separation section 62, the impurity separation section 64, and the chemical purification section 66. In addition, based on the analysis results of the second liquid analyzer 121, the control device 140 switches between injecting and stopping the drug using the second drug addition device 170, and between introducing and stopping the air using the air introduction device 116, and also controls the first switching valve V121, the second switching valve V122, and the first to fourth check valves V123, V124, V131, and V132.

[0247] This configuration allows the geothermal power generation system 100 to clean the return line L100 even during normal operation (power generation). The control device 140 controls the air introduction device 116 to introduce air into the chemical agent supplied by the second chemical agent addition device 170. The control device 140 then controls the first selector valve V121, the second selector valve V122, and the first through fourth gate valves V123, V124, V131, and V132 to switch the flow path of the return line L100 to the first bypass pipe L121 and the second bypass pipe L122, allowing the chemical agent with the introduced air to flow through the return line L100. This reduces the contact area between the chemical agent and the geothermal water and prevents dilution of the chemical agent while it flows through the return line L100. Furthermore, the control device 140 controls the second chemical agent addition device 170 to supply a corrosive agent, allowing the control device 140 to determine the cleaning state based on the concentration of metal ions detected by the second liquid analyzer 121. Therefore, the geothermal power generation system 100 can continue cleaning until the return line L100 is sufficiently cleaned. As described above, the geothermal power generation system 100 can sufficiently remove scale from the return line L100 even during normal operation.

[0248] Furthermore, the waste liquid after cleaning the return line L100 is adjusted by the waste liquid adjustment device 67 in the waste liquid recovery section 61, scale separation section 62, first chemical recovery section 63, impurity separation section 64, second chemical recovery section 65, and chemical purification section 66, where scale-containing substances and impurities are separated and removed in order, and the waste liquid is purified. Thus, the geothermal power generation system 1 can obtain a purified regenerating chemical from the waste liquid, and the regenerating chemical is stored in the regenerating chemical tank 69. As described above, the geothermal power generation system 100 can sufficiently remove scale and recover the chemical used for cleaning.

[0249] In the geothermal power generation system 100, the control device 140 repeats the following operations: normal operation; after the normal operation, a drainage operation in which the geothermal water in the chemical preparation unit 115 is drained; a chemical injection operation in which a chemical is injected into the chemical preparation unit 115 from which the geothermal water has been drained; an air introduction operation in which air is introduced into the chemical injected into the chemical preparation unit 115; a line switching operation in which the flow path of the return line L100 is switched to the first bypass pipe L121 and the second bypass pipe L122 to begin cleaning; and a chemical recovery operation in which, after the line switching operation, the wastewater in the second bypass pipe is circulated to the chemical recovery line L14 to recover the chemical. As a result, the chemical containing air is repeatedly supplied to the geothermal water in the return line L100, and the air surrounding the chemical acts as a barrier, making it difficult for the chemical to diffuse into the geothermal water. This allows the geothermal power generation system 100 to further suppress dilution of the chemical while it flows through the return line L100.

[0250] Geothermal power generation system 100 is equipped with chemical recovery valve V135, and control device 40 causes second liquid analyzer 121 to detect the concentration of air contained in the waste liquid in chemical collection unit 120, and opens chemical recovery valve V135 when the detected concentration reaches a specified value. By detecting air using second liquid analyzer 121, geothermal power generation system 100 can confirm that the chemical has reached chemical collection unit 120, and can therefore send the waste liquid containing the chemical to chemical recovery line L130.

[0251] Although the embodiments have been described above, they are presented as examples and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

[0252] This international application claims priority to Japanese Patent Application No. 2023-117851, filed on July 19, 2023, the entire contents of which are incorporated herein by reference.

[0253] REFERENCE SIGNS LIST 1, 100 Geothermal power generation system 2 Production well 3 Gas-liquid separator 4 Reinjection well 5 Chemical supply port 6 Branch section 9 Flow meter 10 Recovery tank 20 Binary power generation device 21 Media evaporator 30 Analysis device 31 Separation vessel 310 Shaft 311 Housing 312 Geothermal water inlet 313 Geothermal water outlet 314 Gas outlet 315 First solid outlet 319 Second solid outlet 32 ​​Gas analyzer 33 Liquid analyzer 34 First outlet 40 Control device 50 Chemical addition device 51a, 51b, 51c Chemical tank 52 Chemical injection pump 53 Water tank 54 Liquid transfer pump 61 Waste liquid recovery section 62 Scale separation section 63 First chemical recovery section 64 Impurity separation section 65 Second chemical recovery section 66 Chemical purification section 67 Waste liquid adjustment device 68a First analyzer 68b Second analyzer 68c Third analyzer 68d Fourth analyzer 68e Fifth analyzer 68f Sixth analyzer 68g Seventh analyzer 68h Eighth analyzer 68i Ninth analyzer 68j Tenth analyzer 68k Eleventh analyzer 69 Regenerated chemical tank 70a Flocculant tank 70b Dispersant tank 71a Flocculant pump 71b Dispersant pump 72a, 72b Flow meters 73 Scale-containing material recovery tank 74 First adjustment liquid tank 75 Residue recovery tank 76 Primary impurity recovery tank 77 Second adjustment liquid tank 78 Secondary impurity recovery tank 79 Third adjustment liquid tank 80 Heat exchanger 81 Heat pump 101 Power generation device 102 Retention tank 103 Reduction pump 104 Chemical injection port 110 Branching section 111 First liquid analyzer 113 Scale piece collector 113a Residue inlet 113b Dissolving agent injection port 113c Residue discharge port 115 Chemical preparation section 116 Air introduction device 120 Chemical collection section 121 Second liquid analyzer 130 First chemical addition device 131a, 131b, 131c Chemical tank 132a, 132b, 132c Chemical injection pump 140 Control device 150 Dissolving agent addition device 151 Dissolving agent tank 152 Dissolving agent injection pump 170 Second chemical addition device L1 First pipe L2 Second pipe L3 Third pipe L4 Fourth pipeL11 Analysis line L12 Drug supply line L14, L130 Drug recovery lines L14a, L130a First drug recovery line L14b, L130b Second drug recovery line L14c, L130c Third drug recovery line L14d, L130d Fourth drug recovery line L14e, L130e Fifth drug recovery line L100 Return line L101 First piping L102 Second piping L121 First bypass piping L122 Second bypass piping V1 First valve V2 Second valve V3 Third valve V4 Fourth valve V12 First three-way valve V15 Second three-way valve V16 Third three-way valve V17 Fourth three-way valve V101 First valve V102 Second valve V103 Third valve V121 First switching valve V122 Second switching valve V123 First gate valve V124 Second gate valve V131 Third gate valve V132 Fourth gate valve V135 Drug recovery valve R1 First chamber R2 Second chamber R3 Third chamber

Claims

1. A geothermal power generation system equipped with a binary power generation device having a media evaporator, comprising: a gas-liquid separator that separates geothermal water from geothermal fluid spouted from a production well; a first pipe that sends the geothermal water separated by the gas-liquid separator to the media evaporator; a first valve provided in the first pipe for opening and closing a flow path of the first pipe; a second pipe that sends the geothermal water whose heat has been recovered by the binary power generation device from the media evaporator to a reinjection well; an analyzer that introduces the geothermal water flowing through the second pipe and analyzes the components of scale contained in the geothermal water that has flowed in; a control device that determines at least one type of chemical from a plurality of candidate chemicals based on the analysis results of the analyzer and controls the supply of the chemical; a chemical supply port provided in the first pipe downstream of the first valve and through which the chemical is supplied; a third pipe branching off from the second pipe; and a chemical recovery line branching off from the second pipe downstream of the third pipe and connected to the second pipe. A geothermal power generation system comprising: a waste liquid recovery section that accommodates waste liquid after cleaning the first piping and the second piping, a scale separation section that separates the waste liquid into scale-containing matter and primary chemical-containing matter, a first chemical recovery section that accommodates the primary chemical-containing matter, an impurity separation section that separates the primary chemical-containing matter into primary impurities and secondary chemical-containing matter, a second chemical recovery section that accommodates the secondary chemical-containing matter, a chemical purification section that purifies the secondary chemical-containing matter and separates it into secondary impurities and regenerated chemicals, and a regenerated chemical tank that accommodates the regenerated chemical; and a waste liquid adjustment device that supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid accommodated in the scale separation section, the impurity separation section, and the chemical purification section, wherein the waste liquid adjustment device is connected to the scale separation section, the impurity separation section, and the chemical purification section.

2. A geothermal power generation system as described in claim 1, further comprising a first analyzer connected to the waste liquid recovery section for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the fluid contained in the waste liquid recovery section, and the control device causes the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the scale separation section based on the measurement results of the first analyzer, or causes the waste liquid adjustment device to adjust the temperature of the fluid contained in the scale separation section.

3. A geothermal power generation system as described in claim 2, further comprising a second analyzer connected to the first chemical recovery section for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the fluid contained in the first chemical recovery section, and the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the impurity separation section based on the measurement results of the second analyzer, or controls the waste liquid adjustment device to adjust the temperature of the primary chemical-containing material contained in the impurity separation section.

4. A geothermal power generation system as described in claim 3, further comprising a third analyzer connected to the second chemical recovery section for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the fluid contained in the second chemical recovery section, and the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the chemical purification section based on the measurement results of the third analyzer, or controls the waste liquid adjustment device to adjust the temperature of the secondary chemical-containing material contained in the chemical purification section.

5. The geothermal power generation system described in claim 4, wherein the chemical recovery line includes a first chemical recovery line connecting the waste liquid recovery section, the scale separation section, the first chemical recovery section, the impurity separation section, the second chemical recovery section, the chemical purification section, and the regenerated chemical tank, a second chemical recovery line branching off from the first chemical recovery line between the chemical purification section and the regenerated chemical tank, a third chemical recovery line branching off from the second chemical recovery line and connecting to the chemical purification section, a fourth chemical recovery line branching off from the second chemical recovery line and connecting to the impurity separation section, and a fifth chemical recovery line branching off from the second chemical recovery line and connecting to the chemical purification section.

6. A geothermal power generation system as described in claim 5, comprising: a fourth analyzer connected to the chemical purification unit and measuring the concentration of the regenerated chemical purified in the chemical purification unit; and a first three-way valve provided at the branching point between the first chemical recovery line and the second chemical recovery line and switching between a state in which the chemical purification unit communicates with the regenerated chemical tank and a state in which the chemical purification unit communicates with the second chemical recovery line, wherein the control device controls the first three-way valve to communicate between the chemical purification unit and the regenerated chemical tank when the concentration of the regenerated chemical measured by the fourth analyzer reaches a specified value and it is determined that purification is complete.

7. A geothermal power generation system as described in claim 6, comprising: a scale-containing material recovery tank provided in the third chemical recovery line and storing the scale-containing material; a first adjustment liquid tank provided in the third chemical recovery line downstream of the scale-containing material recovery tank and storing adjusted scale-containing material after adjusting the silica concentration, pH or ion concentration; and a fifth analyzer connected to the scale-containing material recovery tank and measuring the temperature, pH, dielectric constant or dissolved ion concentration of the scale-containing material stored in the scale-containing material recovery tank, wherein the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, pH adjuster or ion concentration adjuster to the scale-containing material flowing through the third chemical recovery line between the scale-containing material recovery tank and the first adjustment liquid tank based on the measurement results of the fifth analyzer.

8. A geothermal power generation system as described in claim 7, comprising: a primary impurity recovery tank provided in the fourth chemical recovery line for storing the primary impurities; a second adjustment liquid tank provided in the fourth chemical recovery line downstream of the primary impurity recovery tank for storing adjusted primary impurities after adjusting the silica concentration, pH, or ion concentration; and a sixth analyzer connected to the primary impurity recovery tank for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the primary impurities stored in the primary impurity recovery tank, wherein the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, pH adjuster, or ion concentration adjuster to the primary impurities flowing through the fourth chemical recovery line between the primary impurity recovery tank and the second adjustment liquid tank based on the measurement results of the sixth analyzer.

9. A geothermal power generation system as described in claim 8, comprising: a secondary impurity recovery tank provided in the fifth chemical recovery line for storing the secondary impurities; a third adjustment liquid tank provided in the fifth chemical recovery line downstream of the secondary impurity recovery tank for storing adjusted secondary impurities after adjusting the silica concentration, pH, or ion concentration; and a seventh analyzer connected to the secondary impurity recovery tank for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the secondary impurities stored in the secondary impurity recovery tank, wherein the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, pH adjuster, or ion concentration adjuster to the secondary impurities flowing through the fifth chemical recovery line between the secondary impurity recovery tank and the third adjustment liquid tank based on the measurement results of the seventh analyzer.

10. A geothermal power generation system as described in claim 9, comprising: an eighth analyzer connected to the first adjustment liquid tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted scale-containing material contained in the first adjustment liquid tank; a residue recovery tank provided in the second chemical recovery line upstream of the branching point between the fifth chemical recovery line and the second chemical recovery line; and a second three-way valve provided at the branching point between the third chemical recovery line and the second chemical recovery line, switching between a state in which the first adjustment liquid tank is connected to the reinjection well and a state in which the first adjustment liquid tank is connected to the residue recovery tank; and wherein the control device controls the second three-way valve so that the first adjustment liquid tank is connected to the reinjection well when the concentration of the adjusted scale-containing material measured by the eighth analyzer is within a specified range.

11. A geothermal power generation system as described in claim 10, comprising: a ninth analyzer connected to the second adjustment liquid tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted primary impurities contained in the second adjustment liquid tank; and a third three-way valve provided at the branching point of the fourth chemical recovery line and the second chemical recovery line and switched between a state in which the second adjustment liquid tank is connected to the reinjection well and a state in which the second adjustment liquid tank is connected to the residue recovery tank, wherein the control device controls the third three-way valve to connect the second adjustment liquid tank to the reinjection well when the concentration of the adjusted primary impurities measured by the ninth analyzer is within a specified range.

12. A geothermal power generation system as described in claim 11, comprising: a tenth analyzer connected to the third adjustment liquid tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted secondary impurities contained in the third adjustment liquid tank; and a fourth three-way valve provided at the branching point of the fifth chemical recovery line and the second chemical recovery line and switched between a state in which the third adjustment liquid tank is connected to the reinjection well and a state in which the third adjustment liquid tank is connected to the residue recovery tank, wherein the control device controls the fourth three-way valve to connect the third adjustment liquid tank to the reinjection well when the concentration of the adjusted secondary impurities measured by the tenth analyzer is within a specified range.

13. A gas-liquid separator that separates geothermal water and geothermal steam from geothermal fluid spouted from a production well; a power generation device that generates power using the geothermal water or the geothermal steam separated by the gas-liquid separator as a heat source; a retention tank that stores the geothermal water whose heat has been recovered by the power generation device; a reduction line that connects the outlet of the retention tank to a reduction well; a reduction pump that is provided midway along the reduction line and returns the geothermal water discharged from the retention tank to the reduction well; a chemical injection port that is provided on the reduction line between the retention tank and the reduction pump; a first chemical addition device that injects chemicals into the chemical injection port; a branching section that is provided midway along the reduction line downstream of the reduction pump and vertically above the reduction well and that branches the flow of the geothermal water; and a first liquid analyzer that is connected vertically upward from the branching section. a scale chip collector connected horizontally to the branching portion and having a residue inlet, a dissolving agent inlet, and a residue outlet; a dissolving agent addition device that injects a dissolving agent into the dissolving agent inlet; a control device that switches between an injection operation and a stop of injection of the dissolving agent by the first chemical addition device and between an injection operation and a stop of injection of the dissolving agent by the dissolving agent addition device based on the analysis results of the first liquid analyzer; a chemical recovery line that branches off from a pipe that connects the dissolving agent inlet and the dissolving agent addition device, and is connected to a pipe that connects the branching portion and the reinjection well; A geothermal power generation system comprising: a waste liquid recovery section that accommodates waste liquid after cleaning the reduction line, a scale separation section that separates the waste liquid into scale-containing matter and primary chemical-containing matter, a first chemical recovery section that accommodates the primary chemical-containing matter, an impurity separation section that separates the primary chemical-containing matter into primary impurities and secondary chemical-containing matter, a second chemical recovery section that accommodates the secondary chemical-containing matter, a chemical purification section that purifies the secondary chemical-containing matter and separates it into secondary impurities and regenerative chemicals, and a regenerative chemical tank that accommodates the regenerative chemical; and a waste liquid adjustment device that supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid accommodated in the scale separation section, the impurity separation section, and the chemical purification section, wherein the waste liquid adjustment device is connected to the scale separation section, the impurity separation section, and the chemical purification section.

14. A geothermal power generation system as described in claim 13, comprising a heat exchanger for exchanging heat between the waste liquid and a refrigerant in the scale separation section, and a heat pump for supplying heat recovered by the heat exchanger to the scale debris collector.

15. A geothermal power generation system as described in claim 14, further comprising a second analyzer connected to the first chemical recovery section for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the fluid contained in the first chemical recovery section, and the control device causes the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the scale separation section based on the measurement results of the second analyzer, or causes the waste liquid adjustment device to adjust the temperature of the fluid contained in the scale separation section.

16. A geothermal power generation system as described in claim 15, further comprising a third analyzer connected to the second chemical recovery section for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the fluid contained in the second chemical recovery section, and the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the chemical purification section based on the measurement results of the third analyzer, or controls the waste liquid adjustment device to adjust the temperature of the fluid contained in the chemical purification section.

17. The geothermal power generation system described in claim 16, wherein the chemical recovery line includes a first chemical recovery line connecting the waste liquid recovery section, the scale separation section, the first chemical recovery section, the impurity separation section, the second chemical recovery section, the chemical purification section, and the regenerated chemical tank, a second chemical recovery line branching off from the first chemical recovery line between the chemical purification section and the regenerated chemical tank, a third chemical recovery line branching off from the second chemical recovery line and connecting to the chemical purification section, a fourth chemical recovery line branching off from the second chemical recovery line and connecting to the impurity separation section, and a fifth chemical recovery line branching off from the second chemical recovery line and connecting to the chemical purification section.

18. A geothermal power generation system as described in claim 17, comprising: a fourth analyzer connected to the chemical purification unit and measuring the concentration of the regenerated chemical purified in the chemical purification unit; and a first three-way valve provided at the branching point between the first chemical recovery line and the second chemical recovery line and switching between a state in which the chemical purification unit communicates with the regenerated chemical tank and a state in which the chemical purification unit communicates with the second chemical recovery line, wherein when the concentration of the regenerated chemical measured by the fourth analyzer reaches a specified value and it is determined that purification is completed, the control device controls the first three-way valve to communicate between the chemical purification unit and the regenerated chemical tank.

19. A geothermal power generation system as described in claim 18, comprising: a scale-containing material recovery tank provided in the third chemical recovery line and storing the scale-containing material; a first adjustment liquid tank provided in the third chemical recovery line downstream of the scale-containing material recovery tank and storing the adjusted scale-containing material; and a fifth analyzer connected to the scale-containing material recovery tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the scale-containing material stored in the scale-containing material recovery tank, wherein the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid flowing through the third chemical recovery line between the scale-containing material recovery tank and the first adjustment liquid tank based on the measurement results of the fifth analyzer.

20. A geothermal power generation system as described in claim 19, comprising: a primary impurity recovery tank provided in the fourth chemical recovery line for storing the primary impurities; a second adjustment liquid tank provided in the fourth chemical recovery line downstream of the primary impurity recovery tank for storing the adjusted primary impurities; and a sixth analyzer connected to the primary impurity recovery tank for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the primary impurities stored in the primary impurity recovery tank, wherein the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid flowing through the fourth chemical recovery line between the primary impurity recovery tank and the second adjustment liquid tank based on the measurement results of the sixth analyzer.

21. A geothermal power generation system as described in claim 20, comprising: a secondary impurity recovery tank provided in the fifth chemical recovery line for storing the secondary impurities; a third adjustment liquid tank provided in the fifth chemical recovery line downstream of the secondary impurity recovery tank for storing the adjusted secondary impurities; and a seventh analyzer connected to the secondary impurity recovery tank for measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the secondary impurities stored in the secondary impurity recovery tank, wherein the control device controls the waste liquid adjustment device to supply a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster to the fluid flowing through the fifth chemical recovery line between the secondary impurity recovery tank and the third adjustment liquid tank based on the measurement results of the seventh analyzer.

22. A geothermal power generation system as described in claim 21, comprising: an eighth analyzer connected to the first adjustment liquid tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the scale-containing material after adjustment contained in the first adjustment liquid tank; a residue recovery tank provided in the second chemical recovery line upstream of the branching point between the fifth chemical recovery line and the second chemical recovery line; and a second three-way valve provided at the branching point between the third chemical recovery line and the second chemical recovery line, switching between a state in which the first adjustment liquid tank is connected to the reinjection well and a state in which the first adjustment liquid tank is connected to the residue recovery tank; and the control device controls the second three-way valve to a state in which the first adjustment liquid tank is connected to the reinjection well when the concentration of the scale-containing material after adjustment measured by the eighth analyzer is within a specified range.

23. A geothermal power generation system as described in claim 22, comprising: a ninth analyzer connected to the second adjustment liquid tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted primary impurities contained in the second adjustment liquid tank; and a third three-way valve provided at the branching point of the fourth chemical recovery line and the second chemical recovery line and switching between a state in which the second adjustment liquid tank communicates with the reinjection well and a state in which the second adjustment liquid tank communicates with the residue recovery tank; and wherein the control device controls the third three-way valve to communicate with the second adjustment liquid tank and the reinjection well when the concentration of the adjusted primary impurities measured by the ninth analyzer is within a specified range.

24. A geothermal power generation system as described in claim 23, comprising: a tenth analyzer connected to the third adjustment liquid tank and measuring the temperature, pH, dielectric constant, or dissolved ion concentration of the adjusted secondary impurities contained in the third adjustment liquid tank; and a fourth three-way valve provided at the branching point of the fifth chemical recovery line and the second chemical recovery line and switched between a state in which the third adjustment liquid tank is connected to the reinjection well and a state in which the third adjustment liquid tank is connected to the residue recovery tank; and wherein the control device controls the fourth three-way valve to connect the third adjustment liquid tank to the reinjection well when the concentration of the adjusted secondary impurities measured by the tenth analyzer is within a specified range.

25. A gas-liquid separator that separates geothermal water and geothermal steam from geothermal fluid spouted from a production well; a power generation device that generates power using the geothermal water or the geothermal steam separated by the gas-liquid separator as a heat source; a retention tank that stores the geothermal water whose heat has been recovered by the power generation device; a reduction line that connects the outlet of the retention tank to a reduction well; a reduction pump that is provided in the reduction line and returns the geothermal water discharged from the retention tank to the reduction well; a chemical injection port that is provided in the reduction line between the retention tank and the reduction pump; a first chemical addition device that injects chemicals into the chemical injection port; a branching section that is provided in the reduction line downstream of the reduction pump and vertically above the reduction well and branches the flow of the geothermal water; and a first liquid analyzer that is connected vertically upward from the branching section. a scale chip collector connected horizontally to the branching portion and having a residue inlet, a dissolving agent inlet, and a residue outlet; a dissolving agent addition device for injecting a dissolving agent into the dissolving agent inlet; a control device for switching between an injection operation and a stop of injection of the chemical by the first chemical addition device and switching between an injection operation and a stop of injection of the dissolving agent by the dissolving agent addition device based on an analysis result of the first liquid analyzer; a first bypass pipe branching off from the reduction line downstream of the reduction pump and connected to the reduction line; a second bypass pipe branching off from the reduction line downstream of the first bypass pipe and connected to the reduction line; a first switching valve provided in the reduction line and capable of switching the flow path of the reduction line to the first bypass pipe; and a second switching valve provided in the reduction line and capable of switching the flow path of the reduction line to the second bypass pipe. a drug preparation unit provided in the first bypass piping, a first gate valve provided in the first bypass piping upstream of the drug preparation unit, and a second gate valve provided in the first bypass piping downstream of the drug preparation unit; a second drug addition device that injects a drug into the drug preparation unit; and an air introduction device that supplies air to the drug in the drug preparation unit.a chemical collecting section provided on the second bypass piping, a third gate valve provided on the second bypass piping upstream of the chemical collecting section, and a fourth gate valve provided on the second bypass piping downstream of the chemical collecting section; a second liquid analyzer connected to the chemical collecting section; a chemical recovery line branching off from the second bypass piping and connected to a pipe connecting the branching section and the reinjection well; and a waste liquid recovery section for storing waste liquid after cleaning the reinjection line, a scale separation section for separating the waste liquid into scale-containing matter and primary chemical-containing matter, a first chemical recovery section for storing the primary chemical-containing matter, an impurity separation section for separating the primary chemical-containing matter into primary impurities and secondary chemical-containing matter, a second chemical recovery section for storing the secondary chemical-containing matter, a chemical purification section for purifying the secondary chemical-containing matter and separating it into secondary impurities and regenerated chemical, and a regenerated chemical tank for storing the regenerated chemical. a waste liquid adjustment device that supplies a silica concentration adjuster, a pH adjuster, or an ion concentration adjuster, or adjusts the temperature of the fluid contained in the scale separation unit, the impurity separation unit, and the chemical purification unit, wherein the waste liquid adjustment device is connected to the scale separation unit, the impurity separation unit, and the chemical purification unit, and the control device switches between an injection operation and a stop of injection of the chemical by the second chemical addition device, and switches between an introduction operation and a stop of introduction of air by the air introduction device, based on the analysis results of the second liquid analyzer, and controls the first changeover valve, the second changeover valve, and the first to fourth gate valves.

26. The geothermal power generation system described in claim 25, wherein the control device repeats the following operations: normal operation, after the normal operation, a drainage operation for discharging the geothermal water in the chemical preparation section, a chemical injection operation for injecting the chemical into the chemical preparation section from which the geothermal water has been discharged, an air introduction operation for introducing air into the chemical injected into the chemical preparation section, a line switching operation for switching the flow path of the reduction line to the first bypass piping and the second bypass piping to begin cleaning, and a chemical recovery operation for circulating the waste liquid in the second bypass piping to the chemical recovery line after the line switching operation to recover the chemical.

27. A geothermal power generation system as described in claim 26, further comprising a chemical recovery valve provided in the chemical recovery line upstream of the waste liquid recovery section for opening and closing the flow path between the chemical collection section and the waste liquid recovery section, wherein the control device causes the second liquid analyzer to detect the concentration of air contained in the waste liquid in the second bypass piping, and opens the chemical recovery valve when the detected concentration reaches a specified value.

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