Non-condensable gas reduction system

Abstract

The present disclosure provides a non-condensable gas reduction system that is easy to maintain and returns non-condensable gas contained in geothermal fluid to a reduction well. [Solution] A non-condensable gas reduction system for use in a geothermal power plant, comprising a gas-liquid separator that separates geothermal fluid flowing from a production well into a first gas and a first liquid, a turbine that rotates by the first gas, and a condenser that cools the first gas that rotates the turbine and condenses the steam contained in the first gas into a second liquid, the non-condensable gas reduction system also comprising a pump that pressurizes a third liquid to be sent to a reinjection well, and an ejector that is driven by the third liquid, attracts non-condensable gas contained in the first gas that remains uncondensed in the condenser, and discharges a fourth liquid which is a mixture of the third liquid and the non-condensable gas, in which the first liquid and the fourth liquid are mixed and sent to the reinjection well.

Description

[Technical field]

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

[0002] Patent Document 1 discloses a method for disposing of non-condensable gases generated in geothermal power generation facilities, in which the non-condensable gases generated in a condenser installed downstream of a steam turbine are injected into a reinjection well for hot water reinjection, thereby reducing the gas underground together with the reduced hot water.

[0003] Patent Document 2 discloses a geothermal power plant that includes a reduced water flow path that transports reduced water to a reduced well, a gas extraction device that extracts gas from a condenser, and a gas flow path that supplies the gas extracted from the condenser to the reduced water flow path and mixes it with the reduced water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-177507 [Patent Document 2] JP 2018-017188 A Summary of the Invention [Problem to be solved by the invention]

[0005] In geothermal power generation, if non-condensable gases such as carbon dioxide or hydrogen sulfide are present, the gas accumulates in the upper part of the condenser or evaporator immediately below the turbine, causing a decrease in the degree of vacuum and a decrease in the heat exchange efficiency. In order to prevent a decrease in the degree of vacuum and a decrease in the heat exchange efficiency, the non-condensable gases are removed using an extractor or the like. The extracted non-condensable gases are sent from the condenser or evaporator to a cooling tower, for example, where they are mixed with air and released into the atmosphere.

[0006] The present disclosure provides a non-condensable gas reduction system that is easy to maintain and returns non-condensable gas contained in geothermal fluid to a reduction well. [Means for solving the problem]

[0007] The present disclosure provides a non-condensable gas reduction system for use in a geothermal power plant including a gas-liquid separator that separates a geothermal fluid flowing from a production well into a first gas and a first liquid, a turbine that rotates by the first gas, and a condenser that cools the first gas that rotates the turbine and condenses the steam contained in the first gas into a second liquid, the non-condensable gas reduction system including: a pump that pressurizes a third liquid to be sent to a reinjection well; and an ejector that is driven by the third liquid, attracts non-condensable gas contained in the first gas and remains uncondensed in the condenser, and discharges a fourth liquid that is a mixture of the third liquid and the non-condensable gas, in which the first liquid and the fourth liquid are mixed and sent to the reinjection well. Effect of the Invention

[0008] The present disclosure provides a non-condensable gas reduction system that is easy to maintain and returns non-condensable gas contained in geothermal fluid to a reduction well. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the first embodiment. [Diagram 2] FIG. 2 is a diagram showing an outline of the configuration of the ejector included in the non-condensable gas reduction system according to the first embodiment. [Diagram 3] FIG. 3 is a diagram showing an outline of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the second embodiment. [Figure 4] FIG. 4 is a diagram showing an outline of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the third embodiment. [Diagram 5] FIG. 5 is a diagram illustrating the dissolution determination of non-condensable gas in the non-condensable gas reduction system according to the embodiment of the present disclosure. [Figure 6]FIG. 6 is a diagram illustrating the determination of dissolution of non-condensable gas in the non-condensable gas reduction system according to the embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram illustrating a first example of a process performed in a non-condensable gas reduction system according to an embodiment of the present disclosure when the non-condensable gas is not dissolved. [Figure 8] FIG. 8 is a diagram illustrating a second example of processing in a case where the non-condensable gas is not dissolved in the non-condensable gas reduction system according to the embodiment of the present disclosure. [Figure 9] FIG. 9 is a diagram illustrating a third example of a process when the non-condensable gas is not dissolved in the non-condensable gas reduction system according to the embodiment of the present disclosure. [Figure 10] FIG. 10 is a diagram showing an outline of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the fourth embodiment. [Figure 11] FIG. 11 is a diagram showing an outline of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the fifth embodiment. [Figure 12] FIG. 12 is a diagram showing an outline of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments will be described with reference to the accompanying drawings. Note 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 of the claims.

[0011] In addition, in the description of the specification and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals to avoid redundant explanation. In addition, in order to facilitate understanding, the scale of each part in the drawings may differ from the actual scale.

[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 a geothermal fluid emerging from a production well into a first gas and a first liquid, and a turbine that rotates with the first gas. The geothermal power plant in which the non-condensable gas reduction system according to the first embodiment is used also includes a condenser that cools the first gas that rotates the turbine and condenses the steam contained in the first gas into a second liquid. The non-condensable gas reduction system according to the first embodiment includes a pump that pressurizes a third liquid sent to a 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 that is not condensed in the condenser, and discharges a fourth liquid in which the third liquid and the non-condensable gas are mixed. Then, 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. In the non-condensable gas reduction system according to the first embodiment, the third liquid is a part of the cooling liquid sent to the condenser.

[0013] Next, the non-condensable gas reduction system according to the first embodiment will be described in detail with reference to the drawings. Fig. 1 is a diagram showing an outline of the configuration of a geothermal power plant 1 equipped with 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, a cooling unit 40, a non-condensable gas reduction system 50, and a control unit 60. The geothermal power plant 1 is a so-called flash type geothermal power generation type geothermal power plant. The geothermal power plant 1 also includes a valve 81, a valve 82, and a pump 91.

[0015] [Gas-liquid separator 10] The gas-liquid separator 10 separates the geothermal fluid GF spouting from the production well PWL into steam ST and hot water HW. The geothermal fluid GF spouting from the production well PWL is allowed to flow or blocked by a valve 81. The steam ST discharged from the gas-liquid separator 10 is sent to the power generation section 20. The hot water HW discharged from the gas-liquid separator 10 is discharged to the reinjection well RWL. A pressure gauge 71, described later, measures the pressure of the hot water HW.

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

[0017] [Power Generation Section 20] The power generation unit 20 generates power by using the steam ST. The power generation unit 20 includes a turbine 21 and a generator 22. The turbine 21 is rotated by the steam ST. More specifically, the turbine 21 rotates by the pressure difference between the pressure of the steam ST and the pressure reduced by condensation of the water vapor contained in the steam ST in the condenser 30. The generator 22 is connected to the turbine 21. When the turbine 21 rotates, the rotating shaft of the generator 22 rotates to generate power. The power generated by the generator 22 is supplied to the outside.

[0018] [Condenser 30] The condenser 30 cools the steam ST discharged from the turbine 21 with the cooling liquid CW, more specifically, the cooling liquid CW1, supplied from the cooling section 40. The condenser 30 is a so-called surface contact type condenser. The condenser 30 exchanges heat between the cooling liquid CW1 and the steam ST. The steam ST is cooled by exchanging heat between the cooling liquid CW1 and the steam ST. The steam ST is cooled in the condenser 30, and condenses into water (second liquid). In the condenser 30, which is a surface contact type condenser, for example, the cooling liquid CW1 flows inside the piping of the heat exchanger, so that the cooling liquid CW1 does not come into direct contact with the steam ST.

[0019] Non-condensable gas NCG such as carbon dioxide and hydrogen sulfide contained in the steam ST accumulates in the upper part of the condenser 30. When the non-condensable gas NCG accumulates, the pressure in the condenser 30 increases. When the pressure in the condenser 30 increases, the driving force for rotating the turbine 21 decreases. When the driving force for rotating the turbine 21 decreases, the power generation efficiency in the power generation unit 20 decreases. Therefore, it is desirable to discharge the non-condensable gas NCG accumulated in the condenser 30 from the condenser 30.

[0020] In the geothermal power plant 1, the non-condensable gas NCG accumulated in the condenser 30 is attracted by the non-condensable gas reduction system 50 and discharged to the reduction well RWL.

[0021] [Cooling section 40] The cooling unit 40 supplies a cooling liquid CW to cool the steam ST in the condenser 30. The cooling unit 40 is, for example, a cooling tower. The cooling liquid CW1 cooled in the cooling unit 40 is sent to the condenser 30 by a pump 91. The cooling liquid CW2 whose temperature has increased by heat exchange with the steam ST in the condenser 30 is returned to the cooling unit 40 and cooled.

[0022] [Non-condensable gas reduction system 50] The non-condensable gas reduction system 50 induces and discharges the non-condensable gas NCG from the condenser 30. 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 coolant CW, more specifically, the coolant CWa which is a part of the coolant CW1. The coolant CWa is pumped by the pump 92. The ejector 54 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the coolant CWa.

[0023] The mixed liquid MW discharged from the ejector 54 is mixed with the hot water HW and sent to the reinjection well RWL. The mixed liquid MW and the hot water HW sent to the reinjection well RWL are allowed to flow or blocked by a valve 82.

[0024] The following describes the structure of the ejector 54. 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.

[0025] The ejector 54 includes an induction section 51, a drive nozzle 52, and an expansion section 53. The induction section 51 has an induction port 51a. Non-condensable gas NCG is sucked in from the induction port 51a. The drive nozzle 52 is inserted into the induction section 51. The drive port 52a of the drive nozzle 52 is supplied with pressurized cooling liquid CWa by the pump 92. The high-speed cooling liquid CWa is discharged from the tip of the drive nozzle 52, and the non-condensable gas NCG present in the induction section 51 is discharged while being mixed with the cooling liquid CWa. As the non-condensable gas NCG is discharged, the ejector 54 sucks in the non-condensable gas NCG.

[0026] The ejector 54 mixes the non-condensable gas NCG with the cooling liquid CWa, and discharges the mixed liquid MW through the expanded tube portion 53.

[0027] The non-condensable gas NCG and the coolant CWa are mixed in the ejector 54 and the mixed liquid MW discharged is mixed with the hot water HW and sent to the reinjection well RWL.

[0028] The ejector 54 is provided on the ground. By providing the ejector 54 on the ground, maintenance of the ejector 54 can be facilitated.

[0029] The control device 58 is mainly configured with 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 central processing unit (CPU), a graphics processing unit (GPU), or a micro processing unit (MPU). The control device 58 may be, for example, a programmable logic controller (PLC).

[0030] When pressure P1 on pressure gauge 71 becomes higher than pressure P2 on pressure gauge 73 during power generation, control device 58 controls valve 83 to close in order to prevent hot water HW from flowing to the condenser 30. Valve 83 is provided in a flow path through which non-condensable gas NCG flows between the condenser 30 and ejector 54. Note that pressure P1 on pressure gauge 71 is the pressure of the hot water HW, and pressure P2 on pressure gauge 73 is the discharge pressure of pump 92.

[0031] The controller 58 may also use a pressure gauge 72 to monitor the pressure of the non-condensable gas NCG.

[0032] [Control unit 60] The control unit 60 controls the entire geothermal power plant 1. The control unit 60 is mainly configured with 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.

[0033] The control unit 60 controls the pump 91. When generating power, the control unit 60 controls the pump 91 to start up. When stopping power generation, the control unit 60 controls the pump 91 to stop.

[0034] Geothermal power generation emits mainly carbon dioxide as a non-condensable gas, although the amount is far less than that of thermal power generation. For example, 90% of the non-condensable gas contained in the geothermal fluid discharged from production wells is carbon dioxide. Overseas, for example, New Zealand already imposes a carbon tax on carbon dioxide emitted from geothermal power generation. Similarly, in Japan, the cost of geothermal power generation may increase due to the carbon dioxide contained in non-condensable gas.

[0035] According to the non-condensable gas reduction system of the first embodiment, by returning non-condensable gas to the reinjection well, it is possible to reduce non-condensable gas such as carbon dioxide emitted into the atmosphere from geothermal power generation.

[0036] Furthermore, the non-condensable gas reduction system according to the first embodiment uses an ejector that is driven by a cooling liquid and attracts non-condensable gas, thereby reducing the impact on the natural environment, such as the toxicity of hydrogen sulfide contained in the non-condensable gas to the human body and the contamination of surrounding plants and soil.

[0037] The pressure gauge 71 is an example of a first pressure gauge, and the pressure gauge 73 is an example of a second pressure gauge.

[0038] Second Embodiment A non-condensable gas reduction system according to the second embodiment will be described. In the non-condensable gas reduction system according to the second embodiment, the third liquid is a part of the first liquid, instead of being a part of the cooling liquid sent to the condenser in the non-condensable gas reduction system according to the first embodiment.

[0039] Next, the non-condensable gas reduction system according to the second embodiment will be described in detail with reference to the drawings. Fig. 3 is a diagram showing an outline of the configuration of a geothermal power plant 2 equipped with a non-condensable gas reduction system 150, which is an example of the non-condensable gas reduction system according to the second embodiment.

[0040] The geothermal power plant 2 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, 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, a valve 82, and a pump 91. The control unit 160 has the same functions as the control unit 60.

[0041] Regarding the configuration of geothermal power plant 2 that is common to geothermal power plant 1, the description of geothermal power plant 1 should be referred to, and detailed description thereof will be omitted here.

[0042] The non-condensable gas reduction system 150 pressurizes hot water HWa, which is a part of the hot water HW discharged from the gas-liquid separator 10, using a pump 92, and supplies the hot water HWa to an ejector 154. The non-condensable gas reduction system 150 includes an ejector 154, a control device 158, pressure gauges 71, 72, and 73, a valve 83, and a pump 92. The ejector 154 has the same configuration as the ejector 54. The control device 158 has the same function and configuration as the control device 58.

[0043] The ejector 154 is driven by hot water HWa which is a part of the hot water HW discharged from the gas-liquid separator 10. The hot water HWa is pumped by the pump 92. The ejector 154 discharges a mixed liquid MW which is a mixture of the non-condensable gas NCG and the hot water HWa.

[0044] The ejector 154 mixes the non-condensable gas NCG and the hot water HWa and discharges the mixed liquid MW. The mixed liquid MW, which is the mixture of the non-condensable gas NCG and the hot water HWa and discharged in the ejector 154, is mixed with the hot water HW and sent to the reinjection well RWL.

[0045] According to the non-condensable gas reduction system of the second embodiment, as in the non-condensable gas reduction system of the first embodiment, non-condensable gases such as carbon dioxide emitted into the atmosphere from geothermal power generation can be reduced by returning the non-condensable gas to the reduction well.

[0046] Third Embodiment A non-condensable gas reduction system according to the third embodiment will be described. A geothermal power plant equipped with the non-condensable gas reduction system according to the third embodiment further includes a reduction pit for storing the first liquid. In the non-condensable gas reduction system according to the third embodiment, the third liquid is a part of the first liquid stored in the reduction pit, instead of being a part of the cooling liquid sent to the condenser in the non-condensable gas reduction system according to the first embodiment.

[0047] Next, the non-condensable gas reduction system according to the third embodiment will be described in detail with reference to the drawings. Fig. 4 is a diagram showing an outline of the configuration of a geothermal power plant 3 equipped with a non-condensable gas reduction system 250, which is an example of the non-condensable gas reduction system according to the third embodiment.

[0048] The geothermal power plant 3 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, a cooling unit 40, a non-condensable gas reduction system 250, and a control unit 260. The geothermal power plant 3 also includes valves 81 and 82, pumps 91 and 293, and a reduction pit 211. The control unit 260 has the same functions as the control unit 60.

[0049] Regarding the configuration of geothermal power plant 3 that is common to geothermal power plant 1, the description of geothermal power plant 1 should be referred to, and detailed description thereof will be omitted here.

[0050] The geothermal power plant 3 includes a reduction pit 211 that stores the hot water HW discharged from the gas-liquid separator 10. The hot water HW stored in the reduction pit 211 is sent to the reduction well RWL by a pump 293. In addition, hot water HWb, which is a part of the hot water HW stored in the reduction pit 211, is pressurized by a pump 92 and supplied to the ejector 254. The reduction pit 211 may be a tank or a pool.

[0051] The non-condensable gas reduction system 250 includes an ejector 254, a control device 258, a pressure gauge 271, a pressure gauge 72, and a pressure gauge 73, a valve 83, and a pump 92. The non-condensable gas reduction system 250 measures the pressure P1 of the hot water HW by a pressure gauge 271 instead of the pressure gauge 71 in the non-condensable gas reduction system 50. The ejector 254 has the same configuration as the ejector 54. The control device 258 has the same function and configuration as the control device 58. The non-condensable gas reduction system 250 pressurizes hot water HWb, which is a part of the hot water HW stored in the reduction pit 211, by a pump 92 and supplies the hot water HWb to the ejector 254.

[0052] The ejector 254 is driven by hot water HWb, which is a part of the hot water HW stored in the reduction pit 211. The hot water HWb is pumped by a pump 92. The ejector 254 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the hot water HWb.

[0053] The ejector 254 mixes the non-condensable gas NCG and the hot water HWb and discharges the mixed liquid MW. The mixed liquid MW, which is the mixture of the non-condensable gas NCG and the hot water HWb and discharged in the ejector 254, is mixed with the hot water HW and sent to the reinjection well RWL.

[0054] According to the non-condensable gas reduction system of the third embodiment, as in the non-condensable gas reduction system of the first embodiment, non-condensable gases such as carbon dioxide emitted into the atmosphere from geothermal power generation can be reduced by returning the non-condensable gas to the reduction well.

[0055] <Determination of dissolution of non-condensable gas in a non-condensable gas reduction system according to an embodiment of the present disclosure> In the non-condensable gas reduction system according to the embodiment of the present disclosure, a method for determining whether the non-condensable gas is dissolved 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.

[0056] 5 and 6 are diagrams for explaining dissolution determination of non-condensable gas in the non-condensable gas reduction system according to the embodiment of the present disclosure. In the following explanation, the ejector 54 is used. The same applies when the ejector 154 or the ejector 254 is used instead of the ejector 54.

[0057] A tank 355 is provided downstream of the ejector 54. A level gauge 374 is provided in the tank 355. The level gauge 374 measures the level of the liquid stored in the tank 355. The measurement result is output to the control device 358. The control device 358 executes a dissolution determination of the non-condensable gas NCG.

[0058] As shown in FIG. 6(A), if the non-condensable gas NCG is completely dissolved in the mixed liquid MW, the inside of the tank 355 is filled with the mixed liquid MW. On the other hand, as shown in FIG. 6(B), if the non-condensable gas NCG is not completely dissolved in the mixed liquid MW, the non-condensable gas NCG accumulates at the top of the tank. Therefore, when the non-condensable gas NCG accumulates, the height measured by the level meter 374 decreases by a height ΔL. Therefore, by measuring the level of the mixed liquid MW in the tank 355 using the level meter 374, it is possible to determine whether the non-condensable gas NCG has dissolved in the mixed liquid MW.

[0059] Here, a process when the non-condensable gas NCG is not dissolved will be described. FIG. 7 is a diagram for explaining a first example of a process 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 458 determines that the non-condensable gas NCG is not dissolved based on the level measurement result of the level meter 374, the control device 458 opens the valve 356 provided in the pipe connecting the tank 355 and the ejector 54. By opening the valve 356, the non-condensable gas NCG is sucked from the ejector 54.

[0060] Another example will be described. FIG. 8 is a diagram for describing a second example of the process 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 550 is further provided. And, a pump 557 that supplies a driving flow to the ejector 550 is provided. The non-condensable gas NCG accumulated in the tank 355 is discharged from an ejector 550 other than the ejector 54. When the control device 558 determines that the non-condensable gas NCG is not dissolved based on the level measurement result of the level meter 374, it opens the valve 556, starts the pump 557, and uses the ejector 550 to suck the non-condensable gas NCG in the tank 355. The ejector 550 discharges the mixed liquid MW mixed with the non-condensable gas NCG into the reduction well RWL.

[0061] Further, another example will be described. FIG. 9 is a diagram for explaining a third example of a process 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 third example, a tank 656 for storing a chemical is provided. The chemical is, for example, an alkaline agent. When the control device 658 determines that the non-condensable gas NCG is not dissolved based on the level measurement result of the level meter 374, the control device 658 opens the valve 659 between the tank 355 and the tank 656, and injects the chemical into the tank 355. The chemical is injected, for example, by spraying or pouring from the top of the tank 355.

[0062] The above-mentioned examples may be appropriately combined in each of the non-condensable gas reduction systems according to the first to third embodiments.

[0063] The controller 358, the controller 458, the controller 558, and the controller 658 have the functions of the controllers in the noncondensable gas reduction systems according to the first to third embodiments.

[0064] Fourth Embodiment A non-condensable gas reduction system according to the fourth embodiment will be described below. The non-condensable gas reduction system according to the fourth embodiment includes a plurality of ejectors in the non-condensable gas reduction system according to the first embodiment.

[0065] Next, the non-condensable gas reduction system according to the fourth embodiment will be described in detail with reference to the drawings. Fig. 10 is a diagram showing an outline of the configuration of a geothermal power plant 4 equipped with a non-condensable gas reduction system 750, which is an example of the non-condensable gas reduction system according to the fourth embodiment.

[0066] The geothermal power plant 4 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, a cooling unit 40, a non-condensable gas reduction system 750, a control unit 760, and a pump 91.

[0067] Regarding the configuration of geothermal power plant 4 that is common to geothermal power plant 1, the description of geothermal power plant 1 should be referred to, and detailed description thereof will be omitted here.

[0068] The non-condensable gas reduction system 750 includes a plurality of ejectors 54, a control device 758, a pressure gauge 71, a pressure gauge 72, and a pressure gauge 73, a valve 83, and a pump 92. The non-condensable gas reduction system 750 includes a plurality of ejectors 54, and thus includes a plurality of parallel lines including the ejectors 54. The non-condensable gas reduction system 750 includes a plurality of parallel lines including the ejectors 54, and thus can perform maintenance on the ejectors 54 by operating some of the lines without stopping the entire non-condensable gas reduction system 750.

[0069] According to the non-condensable gas reduction system of the fourth embodiment, as in the non-condensable gas reduction system of the first embodiment, it is possible to reduce non-condensable gases such as carbon dioxide emitted into the atmosphere from geothermal power generation by returning the non-condensable gas to the reinjection well. Furthermore, according to the non-condensable gas reduction system of the fourth embodiment, by providing a plurality of ejectors, it is possible to improve maintainability, for example by switching between them during operation.

[0070] In the example of FIG. 10, a geothermal power plant 4 having a similar configuration to the geothermal power plant 1 equipped with the noncondensable gas reduction system 50, which is an example of the noncondensable gas reduction system according to the first embodiment, has been used as an example for explanation, but is not limited to the noncondensable gas reduction system according to the first embodiment. A geothermal power plant equipped with the noncondensable gas reduction system according to the second or third embodiment may also be provided with a plurality of lines including ejectors. In addition, in the noncondensable gas reduction system according to the fourth embodiment, the above-mentioned process for when the noncondensable gas is not dissolved may be performed. The same applies to the following embodiments.

[0071] Fifth embodiment A non-condensable gas reduction system according to the fifth embodiment will be described. In the non-condensable gas reduction system according to the fifth embodiment, the third liquid is a liquid containing the second liquid, instead of being a part of the cooling liquid sent to the condenser in the non-condensable gas reduction system according to the first embodiment.

[0072] Next, the non-condensable gas reduction system according to the fifth embodiment will be described in detail with reference to the drawings. Fig. 11 is a diagram showing an outline of the configuration of a geothermal power plant 5 equipped with a non-condensable gas reduction system 850, which is an example of the non-condensable gas reduction system according to the fifth embodiment.

[0073] The geothermal power plant 5 includes a gas-liquid separator 10, a power generation unit 20, a condenser 30, a cooling unit 40, a non-condensable gas reduction system 850, and a control unit 860. The geothermal power plant 5 also includes a valve 81, a valve 82, and a pump 91. The control unit 860 has the same functions as the control unit 60.

[0074] Regarding the configuration of geothermal power plant 5 that is common to geothermal power plant 1, the description of geothermal power plant 1 should be referred to, and detailed description thereof will be omitted here.

[0075] The non-condensable gas reduction system 850 pressurizes the condensate HWc (second liquid) of the steam ST in the condenser 30 using a pump 92, and supplies the pressurized liquid to an ejector 854. The non-condensable gas reduction system 850 includes an ejector 854, a control device 858, pressure gauges 71, 72, and 73, a valve 83, and a pump 92. The ejector 854 has the same configuration as the ejector 54. The control device 858 has the same function and configuration as the control device 58.

[0076] The ejector 854 is driven by the condensate HWc of the steam ST in the condenser 30. The condensate HWc is pumped by the pump 92. The ejector 854 discharges a mixed liquid MW in which the non-condensable gas NCG and the condensate HWc are mixed.

[0077] The ejector 854 mixes the non-condensable gas NCG and the condensate HWc and discharges the mixed liquid MW. The mixed liquid MW, which is the mixture of the non-condensable gas NCG and the condensate HWc and discharged in the ejector 854, is mixed with hot water HW and sent to the reinjection well RWL.

[0078] According to the non-condensable gas reduction system of the fifth embodiment, as in the non-condensable gas reduction system of the first embodiment, non-condensable gases such as carbon dioxide emitted into the atmosphere from geothermal power generation can be reduced by returning the non-condensable gas to the reduction well.

[0079] Sixth Embodiment A non-condensable gas reduction system according to a sixth embodiment will be described. In the non-condensable gas reduction system according to the sixth embodiment, the third liquid contains the second liquid and is part of the cooling liquid sent to the condenser, instead of the third liquid being part of the cooling liquid sent to the condenser in the non-condensable gas reduction system according to the first embodiment.

[0080] Next, the non-condensable gas reduction system according to the sixth embodiment will be described in detail with reference to the drawings. Fig. 12 is a diagram showing an outline of the configuration of a geothermal power plant 6 equipped with a non-condensable gas reduction system 950, which is an example of the non-condensable gas reduction system according to the sixth embodiment.

[0081] The geothermal power plant 6 includes a gas-liquid separator 10, a power generation unit 20, a condenser 930, a cooling unit 940, a non-condensable gas reduction system 950, and a control unit 960. The geothermal power plant 6 also includes valves 81 and 82, and pumps 91 and 932. The control unit 960 has the same functions as the control unit 60.

[0082] Regarding the configuration of the geothermal power plant 6 that is common to the geothermal power plant 1, the description of the geothermal power plant 1 should be referred to, and detailed description thereof will be omitted here.

[0083] [Condenser 930] The condenser 930 cools the steam ST discharged from the turbine 21 with the cooling liquid CWA, more specifically, the cooling liquid CWA1, supplied from the cooling unit 940. The condenser 930 is a so-called direct contact condenser. The condenser 930 includes a nozzle unit 931. The nozzle unit 931 includes a plurality of nozzles that spray the cooling liquid CWA1 as a mist. The nozzle unit 931 may include only one nozzle. The condenser 930 performs heat exchange with the steam ST by spraying the cooling liquid CWA1 onto the steam ST and bringing the cooling liquid CWA1 into direct contact with the steam ST. The steam ST is cooled by the heat exchange between the cooling liquid CWA1 and the steam ST. The steam ST is cooled in the condenser 930, and condenses into water (second liquid). In the condenser 930, which is a direct contact condenser, the cooling liquid CWA1 comes into direct contact with the steam ST. The coolant CWA2 contains water (second liquid) that is condensed from the steam ST.

[0084] [Cooling section 940] The cooling unit 940 supplies the cooling liquid CWA to cool the steam ST in the condenser 930. The cooling unit 940 is a cooling tower. The pump 932 sends the cooling liquid CWA2, which has been cooled by cooling the steam ST in the condenser 930 and is at a high temperature, to the cooling unit 940. The cooling unit 940 cools the cooling liquid CWA2. The cooling liquid CWA cooled in the cooling unit 940 is sent to the condenser 930 by the pump 91. The cooling liquid CWA2, whose temperature has increased through heat exchange with the steam ST in the condenser 930, is returned to the cooling unit 40 and cooled.

[0085] The cooling unit 940 is a forced draft type wet cooling tower. The cooling unit 940 brings the cooling liquid CWA2 into direct contact with the air. The cooling unit 940 cools the cooling liquid CWA2 by the transfer of latent heat of evaporation and sensible heat of the cooling liquid CWA2 when the cooling liquid CWA2 comes into direct contact with the air. The cooling unit 940 is a suction type counterflow cooling tower.

[0086] The cooling unit 940 includes a fan 941, a nozzle unit 942, and a filler 943. The fan 941 exhausts outside air taken in from an opening 940h. The nozzle unit 942 includes a plurality of nozzles that spray the cooling liquid CWA2 sent from the condenser 930 as a mist onto the filler 943. Note that the nozzle unit 942 may include only one nozzle.

[0087] As the air passes through the filler 943, the coolant CWA2 sprayed from the nozzle portion 942 exchanges heat with the air.

[0088] The coolant CWA cooled in the cooling section 940 is supplied to the condenser 930 by the pump 91 .

[0089] In the above example, the cooling unit 940 is a suction-type counterflow cooling tower, but the cooling unit of the noncondensable gas reduction system according to this embodiment is not limited to a suction-type counterflow cooling tower. For example, the cooling unit of the noncondensable gas reduction system according to this embodiment may be a forced-type counterflow cooling tower, a suction-type crossflow cooling tower, or a forced-type crossflow cooling tower. In addition, the cooling unit of the noncondensable gas reduction system according to this embodiment may be a natural draft cooling tower.

[0090] [Non-condensable gas reduction system 950] The non-condensable gas reduction system 950 attracts and discharges the non-condensable gas NCG from the condenser 930. The non-condensable gas reduction system 950 is driven by the coolant CWA, more specifically, the coolant CWAa which is a part of the coolant CWA1. The coolant CWAa is pumped by the pump 92. The ejector 954 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the coolant CWAa. The non-condensable gas reduction system 950 includes the ejector 954, a control device 958, a pressure gauge 71, a pressure gauge 72, and a pressure gauge 73, a valve 83, and a pump 92. The ejector 954 has the same configuration as the ejector 54. The control device 958 has the same function and configuration as the control device 58.

[0091] The ejector 954 is driven by a cooling liquid CWAa that is a part of the cooling liquid CWA1. The cooling liquid CWAa includes water (second liquid) that is condensed from the steam ST in the condenser 930. The cooling liquid CWAa is pumped by the pump 92. The ejector 954 discharges a mixed liquid MW that is a mixture of the non-condensable gas NCG and the cooling liquid CWAa.

[0092] The ejector 954 mixes the non-condensable gas NCG and the cooling liquid CWAa and discharges the mixed liquid MW. The mixed liquid MW, which is the mixture of the non-condensable gas NCG and the cooling liquid CWAa and discharged in the ejector 954, is mixed with the hot water HW and sent to the reinjection well RWL.

[0093] According to the non-condensable gas reduction system of the sixth embodiment, as in the non-condensable gas reduction system of the first embodiment, non-condensable gases such as carbon dioxide emitted into the atmosphere from geothermal power generation can be reduced by returning the non-condensable gas to the reduction well.

[0094] The embodiments disclosed herein should be considered as illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0095] 1, 2, 3, 4, 5, 6 Geothermal power plant 10 Gas-liquid separator 20 Power Generation Division 21 Turbine 22 Generator 30, 930 Condenser 40, 940 Cooling section 50, 150, 250, 750, 850, 950 Non-condensable gas reduction system 51 Attraction Section 51a Attraction Port 52 Driving Nozzle 52a Drive port 53 Expanded section 54, 154, 254, 550, 854, 954 Ejector 58, 158, 258, 358, 458, 558, 658, 758, 858, 958 Control device 60, 160, 260, 760, 860, 960 Control unit 71, 72, 73, 271 Pressure gauge 81, 82, 83, 356, 556, 659 Valves 91, 92, 293, 557, 932 Pumps 211 Reduction Pit 355, 656 Tank 374 Level Gauge CW, CW1, CW2, CWa, CWA, CWA1, CWA2, CWAa Coolant GF geothermal fluid HW, HWa, HWb Hot water HWc condensate MW mixture NCG Non-condensable gas PWL Production well RWL Reinjection 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; a turbine that is rotated by the first gas; and a condenser that cools the first gas that rotates the turbine and condenses steam contained in the first gas into a second liquid, A pump for pressurizing the third liquid sent to the reinjection well; an ejector that is driven by the third liquid, attracts non-condensable gas that is contained in the first gas and remains uncondensed in the condenser, and ejects a fourth liquid that is a mixture of the third liquid and the non-condensable gas; 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 portion of the cooling liquid sent to the condenser. The noncondensable gas reduction system of claim 1 .

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

4. 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 .

5. The third liquid includes the second liquid. The noncondensable gas reduction system of claim 1 .

6. The third liquid is a portion of the cooling liquid sent to the condenser which contains the second liquid. The noncondensable gas reduction system of claim 1 .

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

8. a tank connected downstream of the ejector; a level meter for measuring the level of the 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 level meter. The non-condensable gas reduction system according to any one of claims 1 to 6.

9. 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 8.

10. 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 8.

11. 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 8.

12. 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 condenser 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 6.

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