Geothermal power generation system

Abstract

A geothermal power generation system according to one aspect of the present invention comprises: a gas-liquid separator; a power generation device; a retention tank; a reinjection line; a reinjection pump; a chemical injection port provided in the reinjection line between the retention tank and the reinjection pump; a first chemical addition device that injects a chemical into the chemical injection port; a branch part that is provided in the middle of the reinjection line on the downstream side of the reinjection pump and above a reinjection well in the vertical direction, and branches a flow of the geothermal water; a first liquid analyzer; a scale piece collector; a dissolving agent addition device; and a control device that, on the basis of the analysis result of the first liquid analyzer, switches between injecting of the chemical and stopping of injection by the first chemical addition device, and switches between injecting of the dissolving agent and stopping of injection by the dissolving agent addition device.

Description

Technical Field

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

Background Art

[0002] A geothermal power generation system extracts high-temperature geothermal fluid (geothermal water and geothermal steam) from production wells and generates electricity using the geothermal water or geothermal steam separated from the geothermal fluid. The geothermal fluid extracted from production wells contains more calcium, dissolved silica, etc. than well water or river water.

[0003] Calcium and dissolved silica in the geothermal water extracted from production wells are concentrated by being depressurized in the geothermal power generation system, cooled while flowing through the pipes, and the solubility decreases. When silica and dissolved silica in the geothermal water become supersaturated, they polymerize to form calcium carbonate and amorphous silica, which precipitate as scale. Scale may adhere to the inner walls of pipes, etc., causing problems such as pipe blockage. Therefore, in geothermal power generation systems, scale adhesion is a problem.

[0004] In particular, in a geothermal power generation system, scale easily adheres to the reduction line for returning geothermal water to the reinjection well, and it is required to thoroughly clean the scale adhering to the reduction line. For example, in the geothermal power generation system described in Patent Document 1, on the downstream side of the steam-water separator, hydrogen peroxide water is supplied to the separated hot water as an oxidizing agent to prevent scale adhesion of silica components in the geothermal water system.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in typical geothermal power generation systems, the reduction line is laid over long distances, and the cleaning agent supplied upstream of the reduction line becomes diluted as it moves downstream. This leads to insufficient cleaning of scale adhering to the downstream piping, resulting in a cleaning failure.

[0007] One aspect of the present invention provides a geothermal power generation system that can sufficiently remove scale from the reduction line. [Means for solving the problem]

[0008] A geothermal power generation system according to one aspect of the present invention includes: a gas-liquid separator for separating geothermal water and geothermal steam from geothermal fluid ejected from a production well; a power generation device that generates electricity using the geothermal water or geothermal steam separated by the gas-liquid separator as a heat source; a retention tank for storing the geothermal water recovered by the power generation device; a reinjection line connecting the outlet of the retention tank and a reinjection well; a reinjection pump provided in the middle of the reinjection line for returning the geothermal water discharged from the retention tank to the reinjection well; a chemical injection port provided in the reinjection line between the retention tank and the reinjection pump; a first chemical addition device for injecting chemicals into the chemical injection port; and the reinjection The system includes a branching section located downstream of the pump and vertically above the reinjection well, in the middle of the reinjection line, which branches off the flow of the geothermal water; a first liquid analyzer connected vertically upward from the branching section; a scale fragment collector connected horizontally from the branching section, which has a residue inlet, a solvent inlet, and a residue outlet; a solvent addition device for injecting a solvent into the solvent inlet; and a control device that switches the injection operation and injection stop of the solvent by the first solvent addition device, and switches the injection operation and injection stop of the solvent by the solvent addition device, based on the analysis results of the first liquid analyzer. [Effects of the Invention]

[0009] According to one aspect of the present invention, the geothermal power generation system can sufficiently remove scale from the reduction line. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of a geothermal power generation system according to one embodiment. [Figure 2] This is a time chart showing the cleaning operation in a geothermal power generation system according to one embodiment. [Figure 3] This is a schematic diagram showing another example of a geothermal power generation system according to one embodiment. [Figure 4] This is an enlarged view of the main part of Figure 3. [Figure 5A] This is an enlarged view (part 1) of the main part of Figure 3 to illustrate the cleaning operation in another example of a geothermal power generation system according to one embodiment. [Figure 5B] This is a magnified view (part 2) of the main part of Figure 3 to illustrate the cleaning operation in another example of a geothermal power generation system according to one embodiment. [Figure 5C] This is a magnified view (part 3) of the main part of Figure 3 to illustrate the cleaning operation in another example of a geothermal power generation system according to one embodiment. [Figure 5D] This is a close-up view (part 4) of the main part of Figure 3 to illustrate the cleaning operation in another example of a geothermal power generation system according to one embodiment. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. First, an embodiment of the geothermal power generation system 100 in which normal operation (power generation) is stopped and the reduction line L100 is cleaned will be described.

[0012] Figure 1 is a schematic diagram of a geothermal power generation system 100 according to one embodiment. As shown in Figure 1, the geothermal power generation system 100 includes 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, a first chemical addition device 130, and a control device 140. In Figure 1, arrows indicate the flow of fluid.

[0013] In the geothermal power generation system 100, the 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 by the gas-liquid separator 3 are sent to the power generation device 101 via pipes, and the power generation device 101 generates electricity using the geothermal water or geothermal steam separated by the gas-liquid separator 3 as a heat source. The geothermal water from which heat has been recovered by the power generation device 101 is introduced into the retention tank 102 via pipes.

[0014] In the example shown in FIG. 1, the geothermal steam separated by the gas-liquid separator 3 is sent to the flash power generation device 101a, and the flash power generation device 101a generates electricity using the geothermal steam separated by the gas-liquid separator 3 as a heat source. The geothermal water separated by the gas-liquid separator 3 is sent to the binary power generation device 101b, and the binary power generation device 101b generates electricity using the geothermal water separated by the gas-liquid separator 3 as a heat source.

[0015] The power generation device 101 is not particularly limited and may have a flash power generation device 101a and a binary power generation device 101b, or may have either one of the flash power generation device 101a and the binary power generation device 101b.

[0016] The flash power generation device 101a includes a turbine that rotates by supplying the geothermal steam separated by 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 by the condenser, and the like. The binary power generation device 101b includes a medium evaporator that evaporates a low-boiling heat medium by heat exchange, a turbine that rotates by supplying the vaporized heat medium, a generator, a medium condenser, and the like.

[0017] The retention tank 102 stores the geothermal water from which heat has been recovered by the power generation device 101. Then, the polymerization reaction of silica in the geothermal water is allowed to proceed, and the geothermal water is retained until the silica-based insoluble components are sufficiently aggregated and precipitated.

[0018] The reduction line L100 is a line that connects the outlet of the retention tank 102 and the injection well 4.

[0019] The reduction pump 103 is provided in the middle of 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.

[0020] The chemical injection port 104 is provided in the reduction line L100 between the retention tank 102 and the reduction pump 103.

[0021] The first chemical addition device 130 is a device that injects chemicals into the chemical injection port, and may include a plurality of chemical tanks 131a, 131b, 131c for storing chemicals, and a plurality of chemical injection pumps 132a, 132b, 132c connected to each of the plurality of chemical tanks 131a, 131b, 131c and discharging the chemicals toward the chemical injection port 104. The number of chemical tanks 131a, 131b, 131c is three in the example shown in FIG. 1, but is not limited thereto, and can be selected according to the number of chemical species to be used, and may be four or more. The number of chemical injection pumps 132a, 132b, 132c can be selected according to the number of chemical tanks 131a, 131b, 131c.

[0022] The plurality of chemical tanks 131a, 131b, 131c may each contain a tracer reagent, a cleaning agent, and a corrosive agent that is corrosive to the metal constituting the reduction line L100. 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.

[0023] The tracer reagent is a chemical used to confirm that the washing 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-naphthylamine disulfonic acid (amino G acid), metal indicators, and benzoic acid. Among these, aromatic sulfonates are preferred as the tracer reagent.

[0024] The cleaning agent is a chemical used to remove and clean scale adhering to the inside of the piping of the reduction line L100. The cleaning agent may be a chemical containing one or more selected from, for example, acidic agents, basic agents, chelating agents, hydrogen peroxide-based agents, dispersants, and catalase-based agents.

[0025] 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 under pH adjustment before using other cleaning agents, thereby reducing 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. Hydrogen peroxide-based agents can be used to dissolve soft sludge. 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 and various surfactants. Catalase-based agents can be used to decompose hydrogen peroxide-based agents remaining in geothermal water after their use.

[0026] The corrosive agent is a chemical that is circulated through the reduction line L100 after cleaning to dissolve the metals that make up the piping of the reduction line L100, and the cleaning status is determined by the concentration of the dissolved metal ions. The corrosive agent can be one selected from, for example, sulfuric acid, hydrochloric acid, acetic acid, and citric acid.

[0027] 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 in the middle of the fourth pipe L104 to open and close the flow path of the fourth pipe L104. The first chemical addition device 130 may also include a sixth pipe L106 branching off from the fourth pipe L104 and connected to the discharge port of the chemical injection pump 132a, a seventh pipe L107 branching off from the fourth pipe L104 and connected to the discharge port of the chemical injection pump 132b, and an eighth pipe L108 branching off from the fourth pipe L104 and connected to the discharge port of the chemical injection pump 132c.

[0028] The geothermal power generation system 100 may be equipped with a temporary fifth pipe L105 that branches off from the fourth pipe L104 and extends to the inlet of the retention tank 102, depending on the distance between the retention tank 102 and the reduction pump 103, as needed. In this case, the chemical supplied from the first chemical addition device 130 is supplied together with the geothermal water in the retention tank 102 to the reduction line L100 from the outlet of the retention tank 102.

[0029] The geothermal power generation system 100 includes a branching section 110 located downstream of the reduction pump 103 and vertically above the reduction well 4, in the middle of the reduction line L100, which branches the flow of geothermal water; a first liquid analyzer 111 connected vertically upward from the branching section 110; and a scale fragment collector 113 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 also include a first valve V101 (reduction valve) located in the reduction line L100 between the branching section 110 and the reduction well 4, which opens and closes the flow path between the branching section 110 and the reduction well 4.

[0030] The first liquid analyzer 111 is connected to the third pipe L103, which branches off from the branch section 110. The first liquid analyzer 111 analyzes and detects components contained in the fluid. The first liquid analyzer 111 detects at least tracer reagents. 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.

[0031] The geothermal power generation system 100 may include a liquid transfer pump 112 installed in the middle of 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 installed in the third pipe L103 upstream of the liquid transfer pump 112 and opening and closing the flow path of the third pipe L103.

[0032] The scale fragment collector 113 has a residue inlet 113a, a dissolving agent inlet 113b, and a residue discharge inlet 113c, and collects scale fragments flowing through the reduction line L100 with a delay after the cleaning of the reduction line L100 is completed. The geothermal power generation system 100 may include a first pipe L101 connecting the branch section 110 and the residue inlet 113a, and a second valve V102 provided in the first pipe L101 for opening and closing the flow path of the first pipe L101.

[0033] The geothermal power generation system 100 includes a solvent addition device 150 that injects a solvent into the solvent inlet 113b of the scale fragment collector 113. The solvent addition device 150 may have a solvent tank 151 for containing the solvent and a solvent injection pump 152 connected to the solvent tank 151 for discharging the solvent towards the solvent inlet 113b. The solvent is an agent that dissolves the scale collected in the scale fragment collector 113, and can be, for example, one selected from basic agents, fluoride-based agents, and acidic agents.

[0034] For basic and acidic agents, the same agents as those used for the cleaning agents described above can be used. Examples of fluoride-based agents include hydrofluoric acid, hexafluorophosphate, and ammonium fluoride.

[0035] The geothermal power generation system 100 may include a second pipe L102 connecting the solvent inlet 113b and the discharge port of the solvent injection pump 152, and a third valve V103 provided in the second pipe L102 for opening and closing the flow path of the second pipe L102.

[0036] Based on the analysis results from the first liquid analyzer 111, the control device 140 switches between injecting and stopping the drug by the first drug addition device 130, and also switches between injecting and stopping the solvent by the solvent addition device 150. Specifically, based on the analysis results from the first liquid analyzer 111, the control device 140 controls multiple drug injection pumps 132a, 132b, 132c, the solvent injection pump 152, and the first valve V101.

[0037] Figure 2 is a time chart showing the cleaning operation in a geothermal power generation system 100 according to one embodiment. The control device 140 may perform the cleaning operation by having the first chemical addition device 130 supply the cleaning agent and at the same time supply the tracer reagent two or more times with an interval of 5 minutes or more between each supply, and after the first liquid analyzer 111 has detected the tracer reagent the same number of times as the supply, stopping the supply of the cleaning agent and closing the first valve V101 (reduction valve).

[0038] As shown in Figure 2, at time t0, the control device 140 opens the first valve V101 (reduction valve) and sends a command to the tracer reagent injection pump 132a to dispense at least two times with an interval of 5 minutes or more, and also sends a command to the detergent injection pump 132b to continue dispensing. 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, at time t1, the control device 140 sends a command to the detergent injection pump 132b to stop dispensing and simultaneously sends a command to the first valve V101 to close. 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 detergent has reached the downstream side of the reduction line L100. Time T1 is the time required for the detergent to reach the downstream side of the reduction line L100.

[0039] The control device 140 opens the first valve V101 (reduction valve) 2 to 3 hours after it has been closed, and while the first valve V101 is open, it supplies a corrosive agent using the first chemical additive device 130, and then determines the cleaning status based on the concentration of metal ions detected by the first liquid analyzer 111.

[0040] The control device 140, two to three hours (time T2) after the detergent injection pump 132b has stopped and the first valve V101 (reduction valve) has closed (time t1), sends a command to the corrosive agent injection pump 132c to discharge and simultaneously sends a command to the first valve V101 to open (time t2). Time T2 is the time required to allow the detergent to come into sufficient contact with the inner wall of the reduction line L100 piping. Then, after receiving the measured value of the metal ion concentration from the first liquid analyzer 111, the control device 140 determines the cleaning status at time t3, after time T3 has elapsed. Time T3 is the time required to confirm the cleaning status.

[0041] As the cleaning progresses, the inner walls of the pipes are exposed, and the metals that make up the pipes dissolve into the fluid, causing the concentration of metal ions in the fluid to increase. 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 iron ion concentration reaches 100 ppm. The analytical result analyzed by the first liquid analyzer 111 may also be the dielectric constant.

[0042] If the concentration of metal ions detected by the first liquid analyzer 111 is below a specified value, the control device 140 determines that the 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 a 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 time T1 to T3, so it is omitted from Figure 2.

[0043] When the concentration of metal ions detected by the first liquid analyzer 111 reaches a specified value, the control device 140 determines at time t5 that the cleaning is complete, terminates the cleaning operation, and returns to normal operation. The time T5 from time t4 to time t5 is the time of the final of the multiple cleaning status checks T3.

[0044] 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 that cleaning is complete, it flows geothermal water into the residue inlet 113a, collects scale fragments in the scale fragment collector 113, then injects the solvent into the solvent inlet 113b using the solvent addition device 150, and closes the second valve V102 and the third valve V103. Specifically, it is preferable that the control device 140 first opens the second valve V102 for a period of one week or more and flows geothermal water into the residue inlet 113a when it determines that the concentration of metal ions detected by the first liquid analyzer 111 has reached a specified value and that cleaning is complete. This allows the geothermal power generation system 100 to sufficiently collect scale fragments flowing through the reduction line L100 with a delay after cleaning in the scale fragment collector 113. Next, the control device 140 injects the solvent into the solvent inlet 113b using the solvent addition device 150. If the solvent is a basic agent, the control device 140 closes the second valve V102 and the third valve V103 when the pH of the fluid in the scale fragment collector 113 reaches a specified value. The pH of the fluid in the scale fragment collector 113 can be detected, for example, by a pH meter (not shown) provided in the scale fragment collector 113, and the control device 140 receives the pH measurement value from the pH meter.

[0045] Since the scale fragment collector 113 is maintained at a high temperature by the sensible heat of the reduction well 4, the effect of the dissolving agent inside the scale fragment collector 113 is improved, and the dissolution of scale fragments can be promoted. From the viewpoint of promoting the dissolution of scale fragments, it is preferable to position the scale fragment collector 113 so as to maintain the temperature inside the scale fragment collector 113 at 80°C or higher.

[0046] The control device 140 closes the second valve V102 and the third valve V103, leaves them for 48 hours or more, and then opens the second valve V102 to control the fluid containing the dissolved scale fragments in the scale fragment collector 113 to be sent to the injection well 4 via the second pipe L102. Specifically, the control device 140 applies pressure to the scale fragment collector 113 using a pressurizing device (not shown) to push back the geothermal water flowing in from the residue inlet 113a through the opened second valve V102, thereby controlling the fluid containing the dissolved scale fragments in the scale fragment collector 113 to be sent to the injection well 4 via the second pipe L102.

[0047] The control device 140 then controls the discharge of scale fragments, rock fragments, iron rust, etc. remaining in the scale fragment collector 113 to the outside through the residue discharge port 113c.

[0048] The control device 140 may further control the reduction pump 103, the liquid transfer pump 112, the fourth valve V104, the fifth valve V105, and the sixth valve V106.

[0049] Next, another example of the geothermal power generation system 100 will be described. Another example of the geothermal power generation system 100 is an embodiment of the geothermal power generation system 100 in which the reduction line L100 is cleaned during normal operation (power generation). Figure 3 is a schematic configuration diagram showing another example of the geothermal power generation system 100 according to one embodiment, and Figure 4 is an enlarged view of the main part of Figure 3. In Figures 3 and 4, arrows indicate fluid flow.

[0050] In addition to the configuration shown in Figures 1 and 2, the geothermal power generation system 100 may also include, as shown in Figures 3 and 4, a first bypass pipe L121 branching from the reduction line L100 and connected to the reduction line L100 downstream of the reduction pump 103, and a second bypass pipe L122 branching from the reduction line L100 and connected to the reduction line L100 downstream of the first bypass pipe L121. Furthermore, the geothermal power generation system 100 may also include a first switching valve V121 located in the middle of the reduction line L100 and capable of switching the flow path of the reduction line L100 to the first bypass pipe L121, and a second switching valve V122 located in the middle of the reduction line L100 and capable of switching the flow path of the reduction line L100 to the second bypass pipe L122.

[0051] Furthermore, as shown in Figure 4, the geothermal power generation system 100 may include a chemical adjustment unit 115 provided in the first bypass pipe L121, a first gate valve V123 provided in the first bypass pipe L121 upstream of the chemical adjustment unit 115, a second gate valve V124 provided in the first bypass pipe L121 downstream of the chemical adjustment unit 115, a second chemical addition device 170, and an air introduction device 116.

[0052] The chemical adjustment section 115 is the first bypass piping L121 between the first gate valve V123 and the second gate valve V124, and is the part that introduces air into the chemical within the chemical adjustment section 115 and adjusts the chemical supplied to the reduction line L100.

[0053] The second drug dispensing device 170 injects the drug into the drug adjustment unit 115. The second drug dispensing device 170 may have a drug tank 171 for containing the drug and a drug injection pump 172 connected to the drug tank 171 for discharging the drug towards the drug adjustment unit 115. In the example shown in Figure 4, there is one drug tank 171, but the number is not limited to this and can be selected according to the number of drug types used, and there may be multiple drug tanks. The number of drug injection pumps 172 can be selected according to the number of drug tanks 171.

[0054] The chemicals contained in the chemical tank 171 may be a cleaning agent, or a corrosive agent that is corrosive to the metal constituting the cleaning agent and the reduction line L100. There may be multiple chemical tanks 171, and if the chemicals are a cleaning agent and a corrosive agent, the cleaning agent and the corrosive agent are contained in separate chemical tanks 171.

[0055] The cleaning agent is a chemical used to remove scale adhering to the inside of the piping of the reduction line L100 and to clean it. A cleaning agent similar to that used in the embodiment shown in Figure 1 can be used.

[0056] The corrosive agent is a chemical that is circulated through the reduction line L100 after cleaning to dissolve the metals that make up the piping of the reduction line L100, and the cleaning status is determined by the concentration of the dissolved metal ions. As the corrosive agent, the same corrosive agent as in the embodiment shown in Figure 1 can be used.

[0057] The air introduction device 116 supplies air to the chemicals 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 also include an air filter 117 located upstream of the air introduction device 116 and a drainage pump 118 for draining the geothermal water in the chemical preparation unit 115.

[0058] The geothermal power generation system 100 may include a ninth pipe L123 connected to the chemical adjustment 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 middle of the eleventh pipe L125 and connected to the discharge port of the chemical injection pump 172. The drainage pump 118 is located in the middle of the tenth pipe L124.

[0059] The ninth pipe L123 extends vertically downward from the chemical adjustment section 115. The ninth pipe L123 sends cleaning agent and air to the chemical adjustment section 115 and also sends geothermal water discharged from the chemical adjustment section 115 to the tenth pipe L124. The geothermal power generation system 100 may include a thirteenth pipe L127 connected to the chemical adjustment section 115 and extending vertically upward from the chemical adjustment section 115. The thirteenth pipe L127 discharges air from inside the chemical adjustment section 115 to the outside and also introduces air into the chemical adjustment section 115. The geothermal power generation system 100 may include a fifteenth valve V130 located in the middle of the thirteenth pipe L127, which opens and closes the flow path of the thirteenth pipe L127.

[0060] The geothermal power generation system 100 may include a seventh valve V125 located in the middle of the ninth pipe L123 and opening and closing the flow path of the ninth pipe L123; an eighth valve V126 located 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 located in the middle of the eleventh pipe L125 and opening and closing the flow path downstream of the branching point to the twelfth pipe L126 in the eleventh pipe L125; a tenth valve V129 located upstream of the branching point to the twelfth pipe L126; and an eleventh valve V128 located downstream of the chemical injection pump 172 in the twelfth pipe L126 and opening and closing the flow path of the twelfth pipe L126.

[0061] The geothermal power generation system 100 may include an air separation unit 120 provided in the second bypass pipe L122, a third gate valve V131 provided in the second bypass pipe L122 upstream of the air separation unit 120, a fourth gate valve V132 provided in the second bypass pipe L122 downstream of the air separation unit 120, and a second liquid analyzer 121 connected to the air separation unit 120.

[0062] The air separation unit 120 is the part that separates (degasses) air from the fluid (geothermal water and chemicals) inside the air separation unit 120. The second liquid analyzer 121 measures, for example, pH, dielectric constant, or dissolved ion concentration.

[0063] The geothermal power generation system 100 may include a 14th pipe L128 connected to the air separation unit 120 and extending vertically upward, and a 15th pipe L129 connected to the air separation unit 120 and extending vertically downward. The 14th pipe L128 discharges the air separated in the air separation unit 120 to the outside. The geothermal power generation system 100 may also include an air vent valve V133 provided in the middle of the 14th pipe L128. The air vent valve V133 automatically discharges the air accumulated in the air separation unit 120. The 15th pipe L129 connects the air separation unit 120 to the second liquid analyzer 121 and sends the fluid in the air separation unit 120 to the second liquid analyzer 121. The geothermal power generation system 100 may include a liquid transfer pump 122 installed in the middle of the 15th pipe L129 and discharging the fluid flowing through the 15th pipe L129 toward the inlet of the second liquid analyzer 121, and a 12th valve V134 installed in the 15th pipe L129 upstream of the liquid transfer pump 122 and opening and closing the flow path of the 15th pipe L129.

[0064] The control device 140 may, based on the analysis results of the second liquid analyzer 121, switch the injection operation and stop of injection by the second drug addition device 170, and switch the introduction operation and stop of introduction of air by the air introduction device 116, as well as control the first switching valve V121, the second switching valve V122, and the first to fourth gate valves V123, V124, V131, and V132.

[0065] Next, the cleaning operation in another example of the geothermal power generation system 100 will be described in detail. Figures 5A to 5D are enlarged views of the main parts of Figure 3 to illustrate the cleaning operation in another example of the geothermal power generation system 100 according to one embodiment. In Figures 5A to 5D, open valves are shown in white, closed valves are shown in black, and arrows indicate fluid flow.

[0066] The control device 140 may repeatedly perform normal operation, a drainage operation to discharge geothermal water from the chemical preparation unit 115 after 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, and 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 and perform cleaning.

[0067] As shown in Figure 5A, the control device 140 opens the first switching valve V121 and the second switching valve V122, and closes the first to fourth gate valves V123, V124, V131, and V132 during normal operation. During normal operation, geothermal water flows through the reduction line L100 and does not flow through the first bypass pipe L121 and the second bypass pipe L122.

[0068] Next, as shown in Figure 5B, the control device 140, in a drainage operation to discharge geothermal water from the chemical adjustment unit 115, opens the seventh valve V125 and the eighth valve V126, activates the drainage pump 118, and discharges the geothermal water accumulated in the chemical adjustment unit 115, sending 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, which drains the geothermal water accumulated in the chemical adjustment unit 115 and introduces air into the chemical adjustment unit 115 via the thirteenth pipe L127.

[0069] Next, as shown in Figure 5C, the control device 140 closes the eighth valve V126, opens the ninth valve V127 and the eleventh valve V128 in addition to the seventh valve V125, activates the drug injection pump 172, and starts the drug injection operation by the second drug additive device 170. At this time, the drug is injected into the drug adjustment unit 115, and the air inside the drug adjustment unit 115 is discharged to the outside via the thirteenth pipe L127.

[0070] Next, as shown in Figure 5D, the control device 140 closes the 11th valve V128 and the 15th valve V130 during the air introduction operation to introduce air into the drug, and opens the 10th valve V129 in addition to the 7th valve V125 and the 9th valve V127. The control device 140 also stops the drug injection pump 172, stops the injection of drug by the second drug addition device 170, and activates the air introduction device 116 to supply air to the drug in the drug adjustment unit 115 via the 9th pipe L123 and the 11th pipe L125.

[0071] Then, in a line switching operation to start cleaning by switching the flow path of the reduction line L100 to the first bypass pipe L121 and the second bypass pipe L122, 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 flow of the chemical containing air in the chemical adjustment unit 115 to the reduction line L100 and the second bypass pipe L122.

[0072] The air introduced into the chemical in the chemical adjustment section 115 is discharged to the outside via the air vent valve V133 and the 14th pipe L128 in the air separation section 120. That is, the geothermal power generation system 100 separates the air from the fluid (fluid containing geothermal water, chemicals, and air) in the air separation section 120, and then circulates the fluid from which the air has been separated to the reduction line L100 downstream of the second bypass pipe L122.

[0073] After the line switching operation, the control device 140 repeats the normal operation, drainage operation, chemical injection operation, air introduction operation, and line switching operation after a predetermined time has elapsed.

[0074] After the cleaning operation is performed, the control device 140 may close the first switching valve V121 and the second switching valve V122, and with the first to fourth gate valves V123, V124, V131, and V132 open, stop the injection of chemicals by the second chemical additive device 170, and then, after the corrosive agent is supplied by the second chemical additive device 170, determine the cleaning status 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 analytical result analyzed by the first liquid analyzer 111 may be the dielectric constant.

[0075] If the concentration of metal ions detected by the second liquid analyzer 121 is below a specified value, the control device 140 may determine that the cleaning is not complete and repeat the normal operation, drainage operation, chemical injection operation, air introduction operation, and cleaning operation.

[0076] When the concentration of metal ions detected by the second liquid analyzer 121 reaches a specified value, the control device 140 may determine that cleaning is complete, perform normal operation, and terminate subsequent chemical injection, air introduction, and cleaning operations.

[0077] The geothermal power generation system 100 includes 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 additive 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 solvent inlet 113b, and a residue outlet 113c, a solvent additive device 150, and a control device 140 that switches the injection operation and injection stop of chemicals by the first chemical additive device 130, and the injection operation and injection stop of solvents by the solvent additive device 150, based on the analysis results of the first liquid analyzer 111.

[0078] 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 located downstream of the reduction line L100, and switches between injecting and stopping the chemical agent using the first chemical agent addition device 130. Therefore, the geothermal power generation system 100 can clean the reduction line L100 by distributing the chemical agent throughout the entire reduction line L100 from upstream to downstream without opening or disassembling the geothermal power generation system 100 in a closed system state. Furthermore, even if scale fragments flow through the reduction line L100 after cleaning, the geothermal power generation system 100 collects the scale fragments with the scale fragment collector 113, and the control device 140 switches between injecting and stopping the solvent using the solvent addition device 150. Therefore, the geothermal power generation system 100 can dissolve and remove scale fragments flowing through the reduction line L100 after cleaning while maintaining a closed system state 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.

[0079] Specifically, the geothermal power generation system 100 is equipped with a first valve V101, the first chemical addition device 130 has multiple chemical tanks 131a, 131b, 131c and multiple chemical injection pumps 132a, 132b, 132c, and the solvent addition device 150 has a solvent tank 151 and a solvent injection pump 152. Furthermore, the control device 140 controls the multiple chemical injection pumps 132a, 132b, 132c, the solvent injection pump 152, and the first valve V101 based on the analysis results of the first liquid analyzer 111.

[0080] With this configuration, the control device 140 selects a suitable chemical from among several chemicals based on the analysis results of the first liquid analyzer 111, and controls the chemical injection pump that discharges the chemical, thereby enabling the geothermal power generation system 100 to supply the appropriate chemical to the reduction line L100. After the control device 140 has distributed the chemical throughout the entire reduction line L100, it closes the first valve V101, allowing the geothermal power generation system 100 to ensure sufficient contact between the chemical and the inner walls of the piping in the reduction line L100, thereby enhancing the cleaning effect. Furthermore, by controlling the dissolving agent injection pump 152 based on the analysis results of the first liquid analyzer 111, the geothermal power generation system 100 can sufficiently dissolve and remove scale fragments flowing through the reduction line L100 after cleaning. As a result, the geothermal power generation system 100 can more effectively remove scale from the reduction line L100.

[0081] 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 metal constituting the reduction line L100, respectively. This allows the geothermal power generation system 100 to supply the tracer reagent to the reduction line L100 simultaneously with the cleaning agent, enabling the arrival of the cleaning agent to be confirmed by the first liquid analyzer 111, ensuring the cleaning agent reaches the entire reduction line L100 from upstream to downstream, thereby cleaning the reduction line L100. Furthermore, by supplying the corrosive agent to the reduction line L100, the geothermal power generation system 100 can dissolve the metal constituting the piping of the reduction line L100, and the cleaning status can be determined by the concentration of the dissolved metal ions. Therefore, the geothermal power generation system 100 can more effectively remove scale from the reduction line L100.

[0082] In the geothermal power generation system 100, the tracer reagent is preferably an aromatic sulfonate. In the geothermal power generation system 100, by supplying an aromatic sulfonate as a 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.

[0083] In the geothermal power generation system 100, the cleaning agent includes one or more selected from acidic agents, basic agents, chelating agents, hydrogen peroxide-based agents, dispersants, and catalase-based agents. This allows the geothermal power generation system 100 to supply the optimal cleaning agent for each of the soft mud, calcium carbonate, amorphous silica, and iron rust contained in the scale to the reduction line L100.

[0084] 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 a corrosive agent to the reduction line L100, thereby dissolving the iron constituting the piping of the reduction line L100, and the cleaning state can be determined by the concentration of dissolved iron ions.

[0085] In the geothermal power generation system 100, the dissolving agent is selected from basic agents, fluoride-based agents, and acidic agents. This allows the geothermal power generation system 100 to supply the scale fragment collector 113 with the most suitable dissolving agent for each of the calcium carbonate, amorphous silica, etc., contained in the scale.

[0086] In the geothermal power generation system 100, the control device 140 causes the first chemical addition device 130 to supply a cleaning agent, and at the same time, causes the tracer reagent to be supplied two or more times with an interval of 5 minutes or more between each supply. After the first liquid analyzer 111 detects the tracer reagent the same number of times as the supply, the control device 140 stops supplying the cleaning agent and closes the first valve V101 to perform the cleaning operation.

[0087] As a result, the control device 140 confirms the arrival of the cleaning agent using the first liquid analyzer 111, and after distributing the cleaning agent throughout the reduction line L100, closes the first valve V101. This allows the geothermal power generation system 100 to ensure sufficient contact between the cleaning agent and the inner walls of the piping in the reduction line L100, thereby enhancing the cleaning effect. Consequently, the geothermal power generation system 100 can more effectively remove scale from the reduction line L100.

[0088] In the geothermal power generation system 100, the control device 140 opens the first valve V101 2 to 3 hours after closing it, supplies a corrosive agent via the first chemical additive device 130, and then determines the cleaning status based on the concentration of metal ions detected by the first liquid analyzer 111. As a result, the geothermal power generation system 100 can clean the reduction line L100 according to the cleaning status, and can more effectively remove scale from the reduction line L100.

[0089] In the geothermal power generation system 100, the control device 140 determines that cleaning is not complete if the concentration of metal ions detected by the first liquid analyzer 111 is below a specified value, and performs the cleaning operation again, repeating the cleaning operation until the concentration of metal ions detected by the first liquid analyzer 111 reaches a specified value. As a result, the geothermal power generation system 100 can suppress the occurrence of cleaning defects in the reduction line L100 and remove scale from the reduction line L100 more thoroughly.

[0090] The geothermal power generation system 100 is equipped with a second valve V102 and a third valve V103. 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 that cleaning is complete, it flows geothermal water into the residue inlet 113a, collects scale fragments in the scale fragment collector 113, then injects a solvent into the solvent inlet 113b using the solvent addition device 150, and closes the second valve V102 and the third valve V103. As a result, after cleaning the reduction line L100 is complete, if scale fragments flow through the reduction line L100, the geothermal power generation system 100 can collect, dissolve, and remove the scale fragments using the scale fragment collector 113. Therefore, the geothermal power generation system 100 can sufficiently remove scale from the reduction line L100.

[0091] In the geothermal power generation system 100, the control device 140 closes the second valve V102 and the third valve V103, leaves them for 48 hours or more, and then opens the second valve V102 to control the fluid containing the dissolved scale fragments in the scale fragment collector to be sent to the injection well 4 via the second pipe L102. By immersing the scale fragments collected in the scale fragment collector 113 in a solvent in an environment maintained at a high temperature by the sensible heat of the injection well 4, the geothermal power generation system 100 can sufficiently dissolve and remove the scale fragments. Therefore, the geothermal power generation system 100 can more effectively remove scale from the injection line L100.

[0092] In the geothermal power generation system 100, the control device 140 controls the discharge of scale fragments remaining in the scale fragment collector to the outside through the residue discharge port 113c. This allows the control device 140 to remove poorly soluble scale fragments that could not be dissolved by the solvent in the scale fragment collector 113.

[0093] 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 adjustment unit 115, a first gate valve V123, and a second gate valve V124, a second chemical additive device 170, an air introduction device 116, an air separation unit 120, a third gate valve V131, a fourth gate valve V132, and a second liquid analyzer 121. The control device 140 switches the chemical injection operation and injection stop of the second chemical additive device 170, and the air introduction operation and introduction stop of the air introduction device 116 based on the analysis results of the second liquid analyzer 121, and controls the first switching valve V121, the second switching valve V122, and the first to fourth gate valves V123, V124, V131, and V132.

[0094] This configuration allows the geothermal power generation system 100 to clean the reduction line L100 even during normal operation (power generation). The control device 140 introduces air via the air introduction device 116 into the chemical supplied by the second chemical addition device 170. The control device 140 then controls the first switching valve V121, the second switching valve V122, and the first to fourth gate valves V123, V124, V131, and V132 to switch the flow path of the reduction line L100 to the first bypass pipe L121 and the second bypass pipe L122, allowing the chemical with introduced air to flow through the reduction line L100. This reduces the contact area between the chemical and geothermal water, suppressing dilution of the chemical as it flows through the reduction line L100. In addition, the control device 140 can determine the cleaning status based on the concentration of metal ions detected by the second liquid analyzer 121 by supplying a corrosive agent via the second chemical addition device 170. Therefore, the geothermal power generation system 100 can perform cleaning until the reduction line L100 is thoroughly cleaned. As a result, the geothermal power generation system 100 can sufficiently remove scale from the reduction line L100 even during normal operation.

[0095] In the geothermal power generation system 100, the control device 140 repeatedly performs normal operation, a drainage operation to discharge geothermal water from the chemical preparation unit 115 after 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, and a 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. As a result, chemicals containing air are repeatedly supplied into the geothermal water in the reduction line L100, and the air surrounding the chemicals acts as a barrier, making it difficult for the chemicals to diffuse into the geothermal water. Therefore, the geothermal power generation system 100 can further suppress the dilution of the chemicals as they flow through the reduction line L100.

[0096] The geothermal power generation system 100 separates air from the fluid in the air separation section 120, and then flows the fluid from which the air has been separated to the reinjection line L100 downstream of the second bypass pipe L122. This allows the geothermal power generation system 100 to maintain the permeability of the geothermal water that is returned to the reinjection well 4 via the reinjection line L100 downstream of the second bypass pipe L122.

[0097] As described above, embodiments have been explained, but these embodiments are presented as examples only, and the present invention is not limited by these embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, substitutions, and modifications are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0098] This international application claims priority under Japanese Patent Application No. 2023-117850, filed on 19 July 2023, which is incorporated herein by reference in its entirety. [Explanation of Symbols]

[0099] 100 Geothermal power generation systems 2 Production wells 3 Gas-liquid separator 4 Reinforcement well 101 Power generation equipment 102 Retention tank 103 Reduction pump 104 Drug injection port 110 Branching point 111 1st liquid analyzer 113 Scale fragment collector 113a Residue inlet 113b Solvent Inlet 113c Residue outlet 115 Drug Preparation Department 116 Air Inlet Device 120 Air separation unit 121 2nd liquid analyzer 130 First drug dispensing device 131a, 131b, 131c Chemical tanks 132a, 132b, 132c Drug injection pump 140 Control device 150 Solvent Adding Apparatus 151 Dissolving agent tank 152 Solvent injection pump 170 Second drug dispensing device L100 Reduction Line L101 First Piping L102 Second Piping V101 First valve V102 Second valve V103 Third valve L121 First Bypass Piping L122 Second Bypass Piping V121 First switching valve V122 Second switching valve V123 First gate valve V124 Second gate valve V131 Third Gate Valve V132 4th gate valve

Claims

1. A gas-liquid separator separates geothermal water and geothermal steam from the geothermal fluid ejected from the production well, A power generation device that generates electricity using the geothermal water or geothermal steam separated by the gas-liquid separator as a heat source, A retention tank for storing the geothermal water whose heat has been recovered by the power generation device, A reduction line connecting the outlet of the aforementioned retention tank and the reduction well, A reduction pump is installed in the middle of the reduction line and returns the geothermal water discharged from the retention tank to the reduction well, A chemical inlet is provided in the reduction line between the retention tank and the reduction pump, A first drug injection device for injecting the drug into the drug injection port, A branching section is provided in the middle of the reduction line, located downstream of the reduction pump and vertically above the reduction well, which branches the flow of the geothermal water, A first liquid analyzer is connected vertically upward from the aforementioned branching section, A scale fragment collector is connected horizontally from the aforementioned branching section and has a residue inlet, a dissolving agent inlet, and a residue discharge outlet. A dissolving agent adding device for injecting a dissolving agent into the aforementioned dissolving agent inlet, A geothermal power generation system comprising a control device that switches between injecting and stopping the injection of the chemical by the first chemical addition device, and switches between injecting and stopping the injection of the solvent by the solvent addition device, based on the analysis results of the first liquid analyzer.

2. The reduction line between the branching section and the reduction well is provided with a first valve that opens and closes the flow path between the branching section and the reduction well, The first drug dispensing device comprises a plurality of drug tanks for containing the drug, and a plurality of drug injection pumps connected to each of the plurality of drug tanks for discharging the drug toward the drug inlet, The solvent addition device comprises a solvent tank for containing the solvent and a solvent injection pump connected to the solvent tank for discharging the solvent toward the solvent inlet. The geothermal power generation system according to claim 1, wherein the control device controls the plurality of chemical injection pumps, the solvent injection pump, and the first valve based on the analysis results of the first liquid analyzer.

3. The geothermal power generation system according to claim 2, wherein each of the plurality of chemical tanks contains a tracer reagent, a cleaning agent, and a corrosive agent that is corrosive to the metal constituting the reduction line.

4. The geothermal power generation system according to claim 3, wherein the tracer reagent is an aromatic sulfonate.

5. The geothermal power generation system according to claim 3, wherein the cleaning agent comprises 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.

6. The geothermal power generation system according to claim 3, wherein the corrosive agent is one selected from sulfuric acid, hydrochloric acid, acetic acid, and citric acid.

7. The geothermal power generation system according to claim 1, wherein the solvent is one selected from a basic agent, a fluoride-based agent, and an acidic agent.

8. The geothermal power generation system according to claim 3, wherein the control device causes the first chemical addition device to supply the cleaning agent and, at the same time, supplies the tracer reagent two or more times with an interval of five minutes or more between each supply, and after the first liquid analyzer detects the tracer reagent the same number of times as the supply, stops the supply of the cleaning agent and closes the first valve to perform the cleaning operation.

9. The geothermal power generation system according to claim 8, wherein the control device opens the first valve 2 to 3 hours after closing the first valve, supplies the corrosive agent by the first chemical additive device, and then determines the cleaning state based on the concentration of metal ions detected by the first liquid analyzer.

10. The geothermal power generation system according to claim 9, wherein the control device determines that cleaning is not complete if the concentration of the metal ions detected by the first liquid analyzer is less than a specified value, and performs the cleaning operation again, repeating the cleaning operation until the concentration of the metal ions detected by the first liquid analyzer reaches a specified value.

11. A second valve is provided in the first piping that connects the branch section and the residue inlet, and opens and closes the flow path of the first piping. A third valve is provided in the second piping connecting the solvent inlet and the discharge port of the solvent injection pump, and the valve opens and closes the flow path of the second piping. The geothermal power generation system according to claim 10, wherein when the control device determines that the concentration of the metal ions detected by the first liquid analyzer has reached a specified value and that cleaning is complete, it flows the geothermal water into the residue inlet, collects the scale fragments in the scale fragment collector, then injects the solvent into the solvent inlet using the solvent addition device, and closes the second valve and the third valve.

12. The geothermal power generation system according to claim 11, wherein the control device closes the second valve and the third valve, leaves them for 48 hours or more, and then opens the second valve to control the fluid containing the dissolved scale fragments in the scale fragment collector to be sent to the injection well via the second pipe.

13. The geothermal power generation system according to claim 12, wherein the control device controls the discharge of scale fragments remaining in the scale fragment collector to the outside through the residue discharge port.

14. Downstream of the reduction pump, a first bypass pipe branches off from the reduction line and is connected to the reduction line, Downstream of the first bypass piping, a second bypass piping branches off from the reduction line and is connected to the reduction line, A first switching valve is provided in the middle of the reduction line and capable of switching the flow path of the reduction line to the first bypass piping, A second switching valve is provided in the middle of the reduction line and capable of switching the flow path of the reduction line to the second bypass piping, A chemical adjustment unit provided in the first bypass piping, a first gate valve provided in the first bypass piping upstream of the chemical adjustment unit, and a second gate valve provided in the first bypass piping downstream of the chemical adjustment unit, A second drug addition device for injecting the drug into the drug preparation section, An air introduction device that supplies air to the chemical in the chemical preparation section, An air separation unit provided in the second bypass piping, a third gate valve provided in the second bypass piping upstream of the air separation unit, and a fourth gate valve provided in the second bypass piping downstream of the air separation unit, The system includes a second liquid analyzer connected to the air separation unit, The geothermal power generation system according to claim 1, wherein the control device switches between injecting and stopping the injection of the chemical by the second chemical addition device and switching between introducing and stopping the introduction of air by the air introduction device, 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.

15. The geothermal power generation system according to claim 14, wherein the control device repeats normal operation, a drainage operation to discharge the geothermal water in the chemical preparation section after the normal operation, a chemical injection operation to inject the chemical into the chemical preparation section from which the geothermal water has been discharged, an air introduction operation to introduce air into the chemical injected into the chemical preparation section, and a line switching operation to switch the flow path of the reduction line to the first bypass pipe and the second bypass pipe and start cleaning.

16. The geothermal power generation system according to claim 15, wherein after separating air from the fluid in the air separation section, the fluid from which the air has been separated is circulated to the reduction line downstream of the second bypass pipe.

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