Non-condensable gas reduction system

Abstract

The present disclosure provides a non-condensable gas reduction system that returns non-condensable gas contained in highly maintainable geothermal fluid to a reinjection well. 【Solution means】A gas-liquid separator that separates geothermal fluid gushing out from a production well into a first gas and a first liquid, an evaporator that exchanges heat between the first gas and a working medium, a turbine that is rotated by the working medium discharged from the evaporator, and a condenser that cools the working medium that has rotated the turbine and condenses the working medium into a liquid. A non-condensable gas reduction system used in a geothermal power plant, comprising a pump that pressurizes a third liquid sent to a reinjection well, a plurality of ejectors that are driven by the third liquid, attract non-condensable gas contained in the first gas and remaining uncondensed in the evaporator, and discharge a fourth liquid in which the third liquid and the non-condensable gas are mixed, and a plurality of ejectors including any one of the plurality of ejectors. A non-condensable gas reduction system provided in parallel, in which the first liquid and the fourth liquid are mixed and sent to a reinjection well.

Description

Technical Field

[0001] The present disclosure relates to a non-condensable gas reduction system.

Background Art

[0002] Patent Document 1 discloses a method for disposing of non-condensable gas generated in a geothermal power generation facility, in which the non-condensable gas generated in a condenser provided downstream of a steam turbine is injected into a reduction well for hot water reduction, and is reduced underground together with the reduction hot water.

[0003] Patent Document 2 discloses a geothermal power generation plant including a reduction water flow path for transporting reduction water to a reduction well, a gas extraction device for extracting gas from a condenser, and a gas flow path for supplying the gas extracted from the condenser to the reduction water flow path and mixing it into the reduction water.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In geothermal power generation, when non-condensable gas such as carbon dioxide or hydrogen sulfide is contained, gas accumulates at the upper part of the evaporator, the liquid-gas contact area in the evaporator decreases, and the heat exchange efficiency decreases. To prevent the decrease in heat exchange efficiency, the non-condensable gas is removed by an extraction path or an extractor using its own pressure. For example, it is sent from the evaporator to the cooling tower, mixed with air, and released into the atmosphere.

[0006] The present disclosure provides a non-condensable gas reduction system that returns non-condensable gas contained in geothermal fluid with high maintainability to a reduction well.

Means for Solving the Problems

[0007] The present disclosure relates to a non-condensable gas reduction system for a geothermal power plant, which includes a gas-liquid separator that separates geothermal fluid gushing out from a production well into a first gas and a first liquid, an evaporator that performs heat exchange between the first gas and a working medium, a turbine that is rotated by the working medium discharged from the evaporator, and a condenser that cools the working medium that has rotated the turbine and condenses the working medium into a liquid. The non-condensable gas reduction system includes a pump that pressurizes a third liquid sent to a reduction well, and an ejector that is driven by the third liquid, attracts non-condensable gas contained in the first gas and remaining uncondensed in the evaporator, and discharges a fourth liquid in which the third liquid and the non-condensable gas are mixed. The non-condensable gas reduction system is provided in which the first liquid and the fourth liquid are mixed and sent to the reduction well.

Advantages of the Invention

[0008] The present disclosure provides a non-condensable gas reduction system that returns non-condensable gas contained in geothermal fluid with high maintainability to a reduction well.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0010] Hereinafter, embodiments will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0011] Regarding the descriptions in the specifications and drawings according to each embodiment, for components having substantially the same or corresponding functional configurations, the same reference numerals may be given to omit redundant explanations. Also, for ease of understanding, the scales of each part in the drawings may be different from the actual ones.

[0012] <<First Embodiment>> The non-condensable gas reduction system according to the first embodiment will be described. The non-condensable gas reduction system according to the first embodiment is used in a geothermal power plant. The geothermal power plant in which the non-condensable gas reduction system according to the first embodiment is used includes a gas-liquid separator that separates the geothermal fluid gushing out from the production well into a first gas and a first liquid, and an evaporator that performs heat exchange between the first gas and the working medium. Further, the geothermal power plant in which the non-condensable gas reduction system according to the first embodiment is used includes a turbine rotated by the working medium discharged from the evaporator, and a condenser that cools the working medium that has rotated the turbine and condenses the working medium into a liquid. And the non-condensable gas reduction system according to the first embodiment includes a pump that pressurizes a third liquid sent to the reinjection well, and an ejector. The ejector in the non-condensable gas reduction system according to the first embodiment is driven by the third liquid, attracts the non-condensable gas contained in the first gas and remaining uncondensed in the evaporator, and discharges a fourth liquid in which the third liquid and the non-condensable gas are mixed. Further, in the non-condensable gas reduction system according to the first embodiment, the first liquid and the fourth liquid are mixed and sent to the reinjection well. Also, in the non-condensable gas reduction system according to the first embodiment, the third liquid is the condensate in which the first gas has condensed in the evaporator.

[0013] Next, with reference to the drawings, the non-condensable gas reduction system according to the first embodiment will be described in detail. FIG. 1 is a diagram showing an outline of the configuration of a geothermal power plant 1 including a non-condensable gas reduction system 50 which is an example of the non-condensable gas reduction system according to the first embodiment.

[0014] The geothermal power plant 1 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, an evaporator 35, a cooling unit 40, a non-condensable gas reduction system 50, and a control unit 60. The geothermal power plant 1 is a geothermal power plant using a so-called binary geothermal power generation method. Further, the geothermal power plant 1 includes a valve 81 and a valve 82, and a pump 91 and a pump 93.

[0015] [Gas-liquid separator 10] The gas-liquid separator 10 separates the geothermal fluid GF ejected from the production well PWL into steam ST and hot water HW. The geothermal fluid GF ejected from the production well PWL is passed or blocked by the valve 81. The steam ST discharged from the gas-liquid separator 10 is sent to the evaporator 35. The hot water HW discharged from the gas-liquid separator 10 is discharged to the reinjection well RWL. The pressure gauge 71 described later measures the pressure of the hot water HW.

[0016] Here, the steam ST is not pure steam but contains gases discharged from the production well PWL, such as carbon dioxide, hydrogen sulfide, etc.

[0017] [Power generation unit 20] The power generation unit 20 generates electricity using the working medium RF that has been heated by the steam ST and turned into a gas. The power generation unit 20 includes a turbine 21 and a generator 22. The turbine 21 is rotated by the working medium RF. More specifically, the turbine 21 rotates due to the pressure difference between the working medium RF that has exchanged heat with the steam ST in the evaporator 35 and turned from a liquid to a gas, and the working medium RF that has been cooled by the coolant CW1 in the condenser 30 and turned from a gas to a liquid. The generator 22 is connected to the turbine 21. When the turbine 21 rotates, the rotating shaft of the generator 22 rotates to generate electricity. The electricity generated by the generator 22 is supplied to the outside.

[0018] The working medium RF is a medium with a boiling point lower than that of water, such as ammonia, pentane, alternative Freon, etc. The working medium RF condenses from a gas to a liquid when cooled in the condenser 30. Also, the working medium RF evaporates from a liquid to a gas when heated in the evaporator 35. The working medium RF is circulated in the order of the evaporator 35, the turbine 21, and the condenser 30 by the pump 91.

[0019] [Condenser 30] The condenser 30 cools the working medium RF discharged from the turbine 21 with the coolant CW1 supplied from the cooling unit 40. The working medium RF is condensed and changes from a gas to a liquid by being cooled in the condenser 30. The condenser 30 is, for example, a multi-tube heat exchanger, a plate heat exchanger, or the like.

[0020] [Evaporator 35] The evaporator 35 heats the working medium RF with the steam ST supplied from the gas-liquid separator 10. When the evaporator 35 heats the working medium RF, the working medium RF evaporates and changes from a liquid to a gas. The evaporator 35 is, for example, a multi-tube heat exchanger or the like. In the evaporator 35, by performing heat exchange between the steam ST and the working medium RF, the steam ST is cooled. When the steam ST is cooled, the steam ST condenses into the condensate Hwa.

[0021] Non-condensable gases NCG such as carbon dioxide and hydrogen sulfide contained in the steam ST accumulate in the upper part of the evaporator 35. When the non-condensable gas NCG accumulates, the liquid level of the condensate Hwa in which the steam ST has condensed in the evaporator 35 drops. When the liquid level of the condensate Hwa in which the steam ST has condensed in the evaporator 35 drops, the heat exchange efficiency between the steam ST and the working medium RF in the evaporator 35 decreases. Therefore, it is desirable to discharge the non-condensable gas NCG accumulated in the evaporator 35 from the evaporator 35.

[0022] In the geothermal power plant 1, the non-condensable gas NCG accumulated in the evaporator 35 is attracted by the non-condensable gas reduction system 50 and discharged to the reduction well RWL.

[0023] A level meter 84 is provided in the evaporator 35. The level meter 84 measures the liquid level of the condensate Hwa condensed in the evaporator 35. For example, when non-condensable gas NCG accumulates in the evaporator 35, the liquid level measured by the level meter 84 drops.

[0024] [Cooling unit 40] The cooling unit 40 supplies the coolant CW to cool the working medium RF in the condenser 30. The cooling unit 40 is, for example, a cooling tower. The coolant CW1 cooled in the cooling unit 40 is sent to the condenser 30 by the pump 93. In the condenser 30, the coolant CW2 whose temperature has risen by heat exchange with the vapor ST returns to the cooling unit 40 to be cooled.

[0025] [Non-condensable gas reduction system 50] The non-condensable gas reduction system 50 attracts and discharges the non-condensable gas NCG from the evaporator 35. The non-condensable gas reduction system 50 includes an ejector 54, a control device 58, pressure gauges 71, 72 and 73, a valve 83, and a pump 92. The ejector 54 is driven by the condensate Hwa condensed in the evaporator 35. The condensate Hwa is pressure-fed by the pump 92. The ejector 54 discharges a mixed liquid MW in which the non-condensable gas NCG and the condensate Hwa are mixed.

[0026] The mixed liquid MW discharged from the ejector 54 is mixed with the hot water HW and sent to the reduction well RWL. The mixed liquid MW and the hot water HW sent to the reduction well RWL are passed or blocked by the valve 82.

[0027] The structure of the ejector 54 will be described. FIG. 2 is a diagram showing an outline of the configuration of the ejector 54 included in the non-condensable gas reduction system 50 which is an example of the non-condensable gas reduction system according to the first embodiment.

[0028] The ejector 54 includes an induction part 51, a drive nozzle 52, and a diffuser part 53. The induction part 51 has an induction port 51a. The non-condensable gas NCG is sucked from the induction port 51a. Also, the drive nozzle 52 is inserted into the induction part 51. The condensate Hwa pressurized by the pump 92 is supplied to the drive port 52a of the drive nozzle 52. By discharging the high-speed condensate Hwa from the tip of the drive nozzle 52, the non-condensable gas NCG existing in the induction part 51 is discharged while being mixed with the condensate Hwa. By discharging the non-condensable gas NCG, the ejector 54 sucks the non-condensable gas NCG.

[0029] The ejector 54 mixes the non-condensable gas NCG and the condensate Hwa, and discharges the mixed liquid MW through the diffuser section 53.

[0030] In the ejector 54, the mixed liquid MW in which the non-condensable gas NCG and the condensate Hwa are mixed and discharged is mixed with the hot water HW and sent to the reduction well RWL.

[0031] The ejector 54 is provided on the ground. By providing the ejector 54 on the ground, the maintenance of the ejector 54 can be facilitated.

[0032] The control device 58 is mainly composed of a computer including, for example, a processor, a storage device such as a memory, an auxiliary storage device, and an input / output interface device with the outside. The processor is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an MPU (Micro Processing Unit), etc. The control device 58 may be, for example, a programmable logic controller (PLC:Programmable Logic Controller).

[0033] When the liquid level measured by the level meter 84 drops, assuming that the non-condensable gas NCG has accumulated in the evaporator 35, the control device 58 opens the valve 83, operates the pump 92, and discharges the non-condensable gas NCG from the ejector 54.

[0034] Specifically, the level meter 84 measures the liquid level of the condensate HWa in which the vapor ST has condensed in the evaporator 35. Then, the control device 58 controls the opening and closing of the valve 83 according to the level measured by the level meter 84. More specifically, when the liquid level of the condensate HWa in the evaporator 35 measured by the level meter 84 becomes lower than a predetermined liquid level, the control device 58 opens the valve 83 and starts the pump 92. By opening the valve 83 and starting the pump 92, the non-condensable gas NCG is discharged from the evaporator 35 by the ejector 54. Further, when the liquid level of the condensate HWa in the evaporator 35 measured by the level meter 84 becomes higher than a predetermined liquid level, the control device 58 closes the valve 83 and stops the pump 92. By closing the valve 83 and stopping the pump 92, the discharge of the non-condensable gas NCG from the evaporator 35 is stopped.

[0035] During power generation, when the pressure P1 in the pressure gauge 71 becomes higher than the pressure P2 in the pressure gauge 73, the control device 58 controls to close the valve 83 in order to prevent the hot water HW from flowing into the evaporator 35. The valve 83 is provided in the flow path through which the non-condensable gas NCG between the evaporator 35 and the ejector 54 flows. Note that the pressure P1 in the pressure gauge 71 is the pressure of the hot water HW, and the pressure P2 in the pressure gauge 73 is the discharge pressure of the pump 92.

[0036] Further, the control device 58 may monitor the pressure of the non-condensable gas NCG using the pressure gauge 72.

[0037] [Control Unit 60] The control unit 60 controls the entire geothermal power plant 1. The control unit 60 is mainly configured by a computer including, for example, a processor, a storage device such as a memory, an auxiliary storage device, and an input / output interface device with the outside. The processor is, for example, a CPU, a GPU, or an MPU. The control unit 60 may be, for example, a programmable logic controller.

[0038] The control unit 60 controls each of the pumps 91 and 93. When generating electricity, the control unit 60 controls to start each of the pumps 91 and 93. When stopping the power generation, the control unit 60 controls to stop each of the pumps 91 and 93.

[0039] In geothermal power generation, although much less than that by thermal power generation, carbon dioxide is mainly emitted as a non-condensable gas. For example, 90% of the non-condensable gas contained in the geothermal fluid discharged from the production well is carbon dioxide. Overseas, for example, in New Zealand, a carbon tax burden has already occurred for the carbon dioxide discharged from geothermal power generation. Similarly in Japan, the cost of geothermal power generation may increase due to the carbon dioxide contained in the non-condensable gas.

[0040] According to the non-condensable gas reduction system according to the first embodiment, by returning the non-condensable gas to the reinjection well, the non-condensable gas such as carbon dioxide discharged from the geothermal power generation to the atmosphere can be reduced.

[0041] Also, according to the non-condensable gas reduction system according to the first embodiment, by using an ejector that is driven by the condensate in which the first gas has condensed in the evaporator to attract the non-condensable gas, for example, the toxicity of hydrogen sulfide contained in the non-condensable gas to the human body and the impact on the natural environment such as the pollution of surrounding plants and soil can be reduced.

[0042] Note that the pressure gauge 71 is an example of the first pressure gauge, the pressure gauge 73 is an example of the second pressure gauge, and the level gauge 84 is an example of the second level gauge.

[0043] ≪Second Embodiment≫ The non-condensable gas reduction system according to the second embodiment will be described. The non-condensable gas reduction system according to the second embodiment is different from the non-condensable gas reduction system according to the first embodiment in that the third liquid is a part of the coolant sent to the condenser instead of being the condensate in which the first gas has condensed in the evaporator.

[0044] Next, with reference to the drawings, the non-condensable gas reduction system according to the second embodiment will be described in detail. FIG. 3 is a diagram showing an outline of the configuration of a geothermal power plant 2 including a non-condensable gas reduction system 150 which is an example of the non-condensable gas reduction system according to the second embodiment.

[0045] The geothermal power plant 2 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, an evaporator 35, a cooling unit 40, a non-condensable gas reduction system 150, and a control unit 160. The geothermal power plant 2 also includes a valve 81 and a valve 82, and a pump 91 and a pump 93. The control unit 160 has the same functions as the control unit 60.

[0046] Regarding the configurations common to the geothermal power plant 2 and the geothermal power plant 1, the description of the geothermal power plant 1 will be referred to, and detailed descriptions will be omitted here.

[0047] The non-condensable gas reduction system 150 pressurizes a part of the coolant CW, namely the coolant CWa, by a pump 92 and supplies it to an ejector 154. The non-condensable gas reduction system 150 includes an ejector 154, a control device 158, a pressure gauge 71, a pressure gauge 72, and a pressure gauge 73, a valve 83, and a pump 92. The ejector 154 has the same configuration as the ejector 54. Also, the control device 158 has the same functions and configurations as the control device 58.

[0048] The ejector 154 is driven by a part of the coolant CW, namely the coolant CWa. The coolant CWa is pumped by a pump 92. The ejector 154 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the coolant CWa.

[0049] The ejector 154 mixes the non-condensable gas NCG and the coolant CWa and discharges the mixed liquid MW. The mixed liquid MW in which the non-condensable gas NCG and the coolant CWa are mixed and discharged in the ejector 154 is mixed with the hot water HW and the condensate HWa and sent to the reduction well RWL.

[0050] According to the non-condensable gas reduction system according to the second embodiment, similar to the non-condensable gas reduction system according to the first embodiment, by returning the non-condensable gas to the reinjection well, non-condensable gases such as carbon dioxide discharged from geothermal power generation to the atmosphere can be reduced.

[0051] <<Third Embodiment>> The non-condensable gas reduction system according to the third embodiment will be described. In the non-condensable gas reduction system according to the third embodiment, in the non-condensable gas reduction system according to the first embodiment, instead of the third liquid being the condensate in which the first gas condenses in the evaporator, the third liquid is a part of the first liquid.

[0052] Next, with reference to the drawings, the non-condensable gas reduction system according to the third embodiment will be described in detail. FIG. 4 is a diagram showing an outline of the configuration of a geothermal power plant 3 including a non-condensable gas reduction system 250 which is an example of the non-condensable gas reduction system according to the third embodiment.

[0053] The geothermal power plant 3 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, an evaporator 35, a cooling unit 40, a non-condensable gas reduction system 250, and a control unit 260. The geothermal power plant 3 also includes a valve 81 and a valve 82, and a pump 91 and a pump 93. The control unit 260 has the same functions as the control unit 60.

[0054] In the geothermal power plant 3, for the components common to the geothermal power plant 1, the description of the geothermal power plant 1 will be referred to, and here, detailed description will be omitted.

[0055] The non-condensable gas reduction system 250 pressurizes a part of the hot water HW, i.e., hot water HWb, discharged from the gas-liquid separator 10 by a pump 92 and supplies it to an ejector 254. The non-condensable gas reduction system 250 includes an ejector 254, a control device 258, a pressure gauge 71, a pressure gauge 72, and a pressure gauge 73, a valve 83, and a pump 92. The ejector 254 has the same configuration as the ejector 54. The control device 258 has the same functions and configuration as the control device 58.

[0056] The ejector 254 is driven by the hot water HWb which is a part of the hot water HW discharged from the gas-liquid separator 10. The hot water HWb is pumped by the pump 92. The ejector 254 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the hot water HWb.

[0057] The ejector 254 mixes the non-condensable gas NCG and the hot water HWb and discharges the mixed liquid MW. The mixed liquid MW in which the non-condensable gas NCG and the hot water HWb are mixed and discharged in the ejector 254 is mixed with the hot water HW and the condensate HWa and sent to the reinjection well RWL.

[0058] According to the non-condensable gas reduction system according to the third embodiment, similar to the non-condensable gas reduction system according to the first embodiment, by returning the non-condensable gas to the reinjection well, non-condensable gases such as carbon dioxide discharged from geothermal power generation to the atmosphere can be reduced.

[0059] <<Fourth Embodiment>> The non-condensable gas reduction system according to the fourth embodiment will be described. The geothermal power plant equipped with the non-condensable gas reduction system according to the fourth embodiment further includes a reduction pit for storing the first liquid. And, in the non-condensable gas reduction system according to the fourth embodiment, in the non-condensable gas reduction system according to the first embodiment, instead of the third liquid being the condensate in which the first gas is condensed in the evaporator, the third liquid is a part of the first liquid stored in the reduction pit.

[0060] Next, with reference to the drawings, the non-condensable gas reduction system according to the fourth embodiment will be described in detail. FIG. 5 is a diagram showing an outline of the configuration of a geothermal power plant 4 including a non-condensable gas reduction system 350 which is an example of the non-condensable gas reduction system according to the fourth embodiment.

[0061] The geothermal power plant 4 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, an evaporator 35, a cooling unit 40, a non-condensable gas reduction system 350, and a control unit 360. The geothermal power plant 4 also includes a valve 81 and a valve 82, a pump 91 and a pump 93. Furthermore, the geothermal power plant 4 includes a reduction pit 311 and a pump 393. The control unit 360 has the same functions as the control unit 60.

[0062] In the geothermal power plant 4, for the components common to the geothermal power plant 1, the description of the geothermal power plant 1 shall be referred to, and the detailed description is omitted here.

[0063] The geothermal power plant 4 includes a reduction pit 311 for storing the hot water HW discharged from the gas-liquid separator 10. The hot water HW stored in the reduction pit 311 is sent to the reduction well RWL by the pump 393. Also, a part of the hot water HW stored in the reduction pit 311, namely the hot water HWc, is pressurized by the pump 92 and supplied to the ejector 354. The reduction pit 311 may be a tank or a pool.

[0064] The ejector 354 mixes the non-condensable gas NCG and the hot water HWc and discharges a mixed liquid MW. The mixed liquid MW in which the non-condensable gas NCG and the hot water HWc are mixed and discharged in the ejector 354 is mixed with the hot water HW and sent to the reduction well RWL.

[0065] The non-condensable gas reduction system 350 pressurizes a part of the hot water HW stored in the reduction pit 311, namely the hot water HWc, by the pump 92 and supplies it to the ejector 354. The non-condensable gas reduction system 350 includes an ejector 354, a control device 358, pressure gauges 371, 72 and 73, a valve 83, and a pump 92. The non-condensable gas reduction system 350 measures the pressure P1 of the hot water HW by the pressure gauge 371 instead of the pressure gauge 71 in the non-condensable gas reduction system 50. The ejector 354 has the same configuration as the ejector 54. Also, the control device 358 has the same functions and configuration as the control device 58.

[0066] The ejector 354 is driven by the hot water HWc, which is a part of the hot water HW stored in the reduction pit 311. The hot water HWc is pumped by the pump 92. The ejector 354 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the hot water HWc.

[0067] The ejector 354 mixes the non-condensable gas NCG and the hot water HWc and discharges the mixed liquid MW. In the ejector 354, the mixed liquid MW in which the non-condensable gas NCG and the hot water HWc are mixed and discharged is mixed with the hot water HW and sent to the reduction well RWL.

[0068] According to the non-condensable gas reduction system according to the fourth embodiment, similar to the non-condensable gas reduction system according to the first embodiment, by returning the non-condensable gas to the reduction well, non-condensable gases such as carbon dioxide discharged from geothermal power generation into the atmosphere can be reduced.

[0069] ≪Determination of Dissolution of Non-Condensable Gas in Non-Condensable Gas Reduction System According to Embodiment of Present Disclosure≫ In the non-condensable gas reduction system according to the embodiment of the present disclosure, the determination of the dissolution of the non-condensable gas in the mixed liquid discharged by the ejector will be described. In the mixed liquid discharged from the ejector, it is desirable that the non-condensable gas is completely dissolved in the third liquid. Therefore, a method for determining whether the non-condensable gas is dissolved in the third liquid will be described.

[0070] Each of FIGS. 6 and 7 is a diagram for explaining the determination of the dissolution of the non-condensable gas in the non-condensable gas reduction system according to the embodiment of the present disclosure. In the following description, the ejector 54 will be used for explanation. The same applies when using any one of the ejectors 154, 254, or 354 instead of the ejector 54.

[0071] A tank 455 is provided downstream of the ejector 54. A level meter 474 is installed in the tank 455. The level meter 474 measures the level of the liquid stored in the tank 455. The measured result is output to the control device 458. The control device 458 executes the determination of the dissolution of the non-condensable gas NCG.

[0072] As shown in FIG. 7(A), in the mixed liquid MW, when the non-condensable gas NCG is completely dissolved, the inside of the tank 455 is filled with the mixed liquid MW. On the other hand, as shown in FIG. 7(B), in the mixed liquid MW, when the non-condensable gas NCG is not completely dissolved, the non-condensable gas NCG accumulates in the upper part of the tank. Therefore, when the non-condensable gas NCG accumulates, the height measured by the level gauge 474 becomes lower by the height ΔL. Therefore, by measuring the level of the mixed liquid MW in the tank 455 using the level gauge 474, it is possible to determine whether the non-condensable gas NCG is dissolved in the mixed liquid MW.

[0073] Here, the processing when the non-condensable gas NCG is not dissolved will be described. FIG. 8 is a diagram for explaining a first example of the processing when the non-condensable gas is not dissolved in the non-condensable gas reduction system according to the embodiment of the present disclosure. When the control device 558 determines that the non-condensable gas NCG is not dissolved based on the measurement result of the level in the level gauge 474, the control device 558 opens the valve 556 provided in the pipe connecting the tank 455 and the ejector 54. By opening the valve 556, the non-condensable gas NCG is sucked from the ejector 54.

[0074] Also, another example will be described. FIG. 9 is a diagram for explaining a second example of the processing when the non-condensable gas is not dissolved in the non-condensable gas reduction system according to the embodiment of the present disclosure. In the second example, an additional ejector 650 is further provided. And a pump 657 for supplying a driving flow to the ejector 650 is provided. The non-condensable gas NCG accumulated in the tank 455 is discharged from an ejector 650 different from the ejector 54. When the control device 658 determines that the non-condensable gas NCG is not dissolved based on the measurement result of the level in the level gauge 474, the control device 658 opens the valve 656, starts the pump 657, and uses the ejector 650 to suck the non-condensable gas NCG in the tank 455. The ejector 650 discharges the mixed liquid MW in which the non-condensable gas NCG is mixed into the reduction well RWL.

[0075] Furthermore, another example will be described. FIG. 10 is a diagram for explaining a third example of processing when non-condensable gas is not dissolved in the non-condensable gas reduction system according to an embodiment of the present disclosure. In the third example, a tank 756 for storing a chemical agent is provided. The chemical agent is, for example, an alkaline agent. When the control device 758 determines that the non-condensable gas NCG is not dissolved based on the measurement result of the level in the level meter 474, the control device 758 opens the valve 759 between the tank 455 and the tank 756 to inject the chemical agent into the tank 455. The chemical agent is, for example, sprayed or introduced from the upper part of the tank 455.

[0076] The above examples may be appropriately combined in each of the non-condensable gas reduction systems according to the first to fourth embodiments.

[0077] Also, the control devices 458, 558, 658, and 758 have the functions of the control device in the non-condensable gas reduction system according to the first to fourth embodiments.

[0078] Note that the level meter 474 is an example of the first level meter.

[0079] ≪Fifth Embodiment≫ The non-condensable gas reduction system according to the fifth embodiment will be described. The non-condensable gas reduction system according to the fifth embodiment includes a plurality of ejectors in the non-condensable gas reduction system according to the first embodiment.

[0080] Next, with reference to the drawings, the non-condensable gas reduction system according to the fifth embodiment will be described in detail. FIG. 11 is a diagram showing a schematic configuration of a geothermal power plant 5 including a non-condensable gas reduction system 850 which is an example of the non-condensable gas reduction system according to the fifth embodiment.

[0081] The geothermal power plant 5 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, an evaporator 35, a cooling unit 40, a non-condensable gas reduction system 850, and a control unit 860. The geothermal power plant 5 also includes a pump 91 and a pump 93.

[0082] In the geothermal power plant 5, for the components common to the geothermal power plant 1, the description of the geothermal power plant 1 shall be referred to, and the detailed description will be omitted here.

[0083] The non-condensable gas reduction system 850 includes a plurality of ejectors 54, a control device 858, pressure gauges 71, 72, and 73, a valve 83, and a pump 92. The non-condensable gas reduction system 850 includes a plurality of ejectors 54, and thus includes a plurality of lines including the ejectors 54 in parallel. By including a plurality of lines including the ejectors 54 in parallel, the non-condensable gas reduction system 850 can perform maintenance of the ejectors 54 without stopping the entire non-condensable gas reduction system 850 by operating some of the lines.

[0084] According to the non-condensable gas reduction system according to the fifth embodiment, similar to the non-condensable gas reduction system according to the first embodiment, by returning the non-condensable gas to the reinjection well, non-condensable gases such as carbon dioxide discharged from the geothermal power generation to the atmosphere can be reduced. Further, according to the non-condensable gas reduction system according to the fifth embodiment, by providing a plurality of ejectors, for example, by switching and operating, the maintainability can be improved.

[0085] In the example of FIG. 11, the geothermal power plant 5 having the same configuration as the geothermal power plant 1 including the non-condensable gas reduction system 50 which is an example of the non-condensable gas reduction system according to the first embodiment is used as an example for description, but it is not limited to the non-condensable gas reduction system according to the first embodiment. In a geothermal power plant including the non-condensable gas reduction system according to any one of the second to fourth embodiments, a plurality of lines including ejectors may be provided in the same manner. Further, in the non-condensable gas reduction system according to the fifth embodiment, the above-described processing in the case where the non-condensable gas is not dissolved may be performed.

[0086] The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The above embodiments may be omitted, replaced, or changed in various forms without departing from the scope and gist of the appended claims.

Explanation of Reference Numerals

[0087] 1, 2, 3, 4, 5 Geothermal power plants 10 Gas-liquid separator 20 Power generation unit 21 Turbine 22 Generator 30 Condenser 35 Evaporator 40 Cooling unit 50, 150, 250, 350, 850 Non-condensable gas reduction system 51 Suction part 51a Suction port 52 Driving nozzle 52a Driving port 53 Diverging section 54, 154, 254, 354, 650 Ejector 58, 158, 258, 358, 458, 558, 658, 758, 858 Control device 60, 160, 260, 360, 860 Control section 71, 72, 73, 371 Pressure gauge 81, 82, 83, 556, 656, 759 Valve 91, 92, 93, 393, 657 Pump 311 Reduction pit 455, 756 Tank 84, 474 Level gauge CW, CW1, CW2, CWa Cooling liquid GF Geothermal fluid HWa Condensate HW, HWb, HWc Hot water MW Mixed liquid NCG Non-condensable gas PWL Production well RWL Reduction well ST Steam

Claims

1. A non-condensable gas reduction system for use in a geothermal power plant, comprising: a gas-liquid separator that separates a geothermal fluid emerging from a production well into a first gas and a first liquid; an evaporator that performs heat exchange between the first gas and a working medium; a turbine that is rotated by the working medium discharged from the evaporator; and a condenser that cools the working medium that has rotated the turbine and condenses the working medium into a liquid, A pump for pressurizing the third liquid sent to the reinjection well; a plurality of ejectors driven by the third liquid, which attract non-condensable gas contained in the first gas and remaining in the evaporator without being condensed, and which eject a fourth liquid which is a mixture of the third liquid and the non-condensable gas; A plurality of lines including any one of the plurality of ejectors and arranged in parallel; Equipped with The first liquid and the fourth liquid are mixed and sent to the injection well. Non-condensable gas reduction system.

2. The third liquid is a condensed liquid obtained by condensing the first gas in the evaporator. The noncondensable gas reduction system of claim 1 .

3. The third liquid is a portion of the cooling liquid sent to the condenser. The noncondensable gas reduction system of claim 1 .

4. The third liquid is a part of the first liquid. The noncondensable gas reduction system of claim 1 .

5. The geothermal power plant further comprises a reduction pit for storing the first liquid; The third liquid is a portion of the first liquid stored in the reduction pit. The noncondensable gas reduction system of claim 1 .

6. The ejector is installed on the ground. The non-condensable gas reduction system according to any one of claims 1 to 5.

7. a tank connected downstream of the ejector; a first level meter for measuring the level of a liquid stored in the tank; A control device, The control device performs a determination of dissolution of the non-condensable gas in the fourth liquid according to the level measured by the first level meter. The non-condensable gas reduction system according to any one of claims 1 to 5.

8. When the control device determines that the non-condensable gas is not dissolved in the fourth liquid, the control device controls the ejector to discharge the non-condensable gas accumulated in the tank. The noncondensable gas reduction system of claim 7.

9. When the control device determines that the non-condensable gas is not dissolved in the fourth liquid, the control device controls the non-condensable gas accumulated in the tank to be discharged from another ejector different from the ejector to the reinjection well. The noncondensable gas reduction system of claim 7.

10. When the control device determines that the non-condensable gas is not dissolved in the fourth liquid, the control device controls to inject a chemical into the tank. The noncondensable gas reduction system of claim 7.

11. a first pressure gauge that measures a pressure of the first liquid; a second pressure gauge that measures the pressure of the third liquid; a valve provided in a flow path between the evaporator and the ejector; A control device, The control device closes the valve when a pressure of the first liquid measured by the first pressure gauge is higher than a pressure of the third liquid measured by the second pressure gauge. The non-condensable gas reduction system according to any one of claims 1 to 5.

12. a second level meter that measures a liquid level of a condensate formed by condensing the first gas in the evaporator; a valve provided in a flow path between the evaporator and the ejector; A control device, The control device controls opening and closing of the valve according to the level measured by the second level gauge. The non-condensable gas reduction system according to any one of claims 1 to 5.

Images