Non-condensable gas reduction system

Abstract

The present disclosure provides a non-condensable gas reduction system that reduces the effects of atmospheric components contained in gas that is reduced in the reduction well. [Solution] A non-condensable gas reduction system in a geothermal power plant returns non-condensable gas that remains uncondensed when cooled from a first gas contained in geothermal fluid that springs from a production well to a reinjection well. The non-condensable gas reduction system comprises: a pump that pressurizes the first liquid sent to the reinjection well; an ejector that is driven by the first liquid, attracts the non-condensable gas, and discharges a second liquid that is a mixture of the first liquid and the non-condensable gas; and a gas separator connected downstream of the ejector that separates the second gas containing atmospheric components that has been mixed into the second liquid, and discharges the second gas into the atmosphere while discharging the second liquid into 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 being returned underground together with the reinjection 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] Japanese Patent Application Publication No. 2018-017188 Summary of the Invention [Problem to be solved by the invention]

[0005] When non-condensable gases such as carbon dioxide or hydrogen sulfide are injected into a reinjection well in geothermal power generation, if the geothermal water being injected into the reinjection well (reinjection water) contains atmospheric components such as nitrogen and oxygen in addition to the non-condensable gases, corrosion due to oxygen and gas retention in the pipelines and wellhead may occur.If corrosion due to oxygen and gas retention in the pipelines and wellhead occur, poor flow of the geothermal water being injected into the reinjection well (reinjection water) may occur.

[0006] The present disclosure provides a non-condensable gas reduction system that reduces the effects of atmospheric components contained in gases that are reduced in the reinjection well. [Means for solving the problem]

[0007] The present disclosure provides a non-condensable gas reduction system in a geothermal power plant that returns to a reinjection well non-condensable gas that remains uncondensed when cooled in a first gas contained in a geothermal fluid that springs from a production well, the non-condensable gas reduction system comprising: a pump that pressurizes a first liquid sent to the reinjection well; an ejector that is driven by the first liquid, attracts the non-condensable gas, and discharges a second liquid that is a mixture of the first liquid and the non-condensable gas; and a gas separator that is connected downstream of the ejector, separates a second gas containing atmospheric components that has been mixed into the second liquid, and discharges the second gas into the atmosphere while discharging the second liquid into the reinjection well. [Effects of the Invention]

[0008] According to the non-condensable gas reduction system of the present disclosure, the atmospheric components contained in the gas reduced to the reduction well can be reduced, thereby suppressing the effects of the atmospheric components. [Brief explanation 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. [Figure 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. [Figure 3] FIG. 3 is a diagram showing an outline of the configuration of a gas separator included in the noncondensable gas reduction system according to the first embodiment. [Figure 4] FIG. 4 is a flow diagram illustrating the process of the non-condensable gas reduction system according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing an outline of the configuration of a gas separator included in the noncondensable gas reduction system according to the second embodiment. [Figure 6] FIG. 6 is a diagram showing an outline of the configuration of a gas separator included in the noncondensable gas reduction system according to the second embodiment. [Figure 7] FIG. 7 is a diagram showing an outline of the configuration of a gas separator included in the noncondensable gas reduction system according to the third embodiment. [Figure 8] FIG. 8 is a flow diagram illustrating the process of the non-condensable gas reduction system according to the third embodiment. [Figure 9] FIG. 9 is a diagram showing an outline of the configuration of a gas separator included in a noncondensable gas reduction system according to the fourth embodiment. [Figure 10] FIG. 10 is a diagram showing an outline of the configuration of a gas separator included in the noncondensable gas reduction system according to the fifth embodiment. [Figure 11] FIG. 11 is a flow diagram illustrating the process of the 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 gas separator included in a noncondensable gas reduction system according to the sixth embodiment. [Figure 13] FIG. 13 is a flow diagram illustrating the process of the non-condensable gas reduction system according to the sixth embodiment. [Figure 14] FIG. 14 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 seventh embodiment. [Figure 15] FIG. 15 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 eighth embodiment. [Figure 16] FIG. 16 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 ninth embodiment. DETAILED DESCRIPTION OF THE INVENTION

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

[0012] First Embodiment A non-condensable gas reduction system according to a first embodiment will be described. The non-condensable gas reduction system according to the first embodiment is a non-condensable gas reduction system that returns to a reinjection well the non-condensable gas that remains uncondensed when cooled in a first gas contained in geothermal fluid that flows from a production well in a geothermal power plant. The non-condensable gas reduction system according to the first embodiment includes a pump that pressurizes the first liquid sent to the reinjection well, and an ejector that is driven by the first liquid, attracts the non-condensable gas, and discharges a second liquid that is a mixture of the first liquid and the non-condensable gas. The non-condensable gas reduction system according to the first embodiment also includes a gas separator connected downstream of the ejector that separates the second gas containing atmospheric components that has been mixed into the second liquid, discharges the second gas into the atmosphere, and discharges the second liquid into the reinjection well.

[0013] The gas separator according to the first embodiment is a baffle-type gas separator.

[0014] 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.

[0015] 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 geothermal power generation type geothermal power plant. The geothermal power plant 1 also includes a valve 81, a valve 82, and a pump 91.

[0016] [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 is 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.

[0017] Here, the steam ST is not pure steam, but contains gases discharged from the production well PWL, such as carbon dioxide and hydrogen sulfide.

[0018] [Power Generation Unit 20] The power generation unit 20 generates electricity 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 due to the pressure difference between the pressure of the steam ST and the pressure reduced by condensation of 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, generating electricity. The electricity generated by the generator 22 is supplied to the outside.

[0019] [Condenser 30] The condenser 30 cools the steam ST discharged from the turbine 21 with the coolant CW, more specifically the coolant CW1, supplied from the cooling unit 40. The condenser 30 is a so-called surface contact condenser. The condenser 30 exchanges heat between the coolant CW1 and the steam ST. The steam ST is cooled by exchanging heat between the coolant CW1 and the steam ST. The steam ST is cooled in the condenser 30, and condenses into water. In the condenser 30, which is a surface contact condenser, for example, the coolant CW1 flows inside the piping of the heat exchanger, so that the coolant CW1 does not come into direct contact with the steam ST.

[0020] Non-condensable gases NCG such as carbon dioxide and hydrogen sulfide contained in the steam ST accumulate 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.

[0021] In the geothermal power plant 1, 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.

[0022] [Cooling section 40] The cooling unit 40 supplies a coolant CW to cool the steam ST 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 a pump 91. The coolant CW2, whose temperature has increased through heat exchange with the steam ST in the condenser 30, is returned to the cooling unit 40 and cooled.

[0023] For example, if the cooling unit 40 is a cooling tower, the coolant CW2 is cooled by exchanging heat with the atmosphere. When the coolant CW2 is cooled by exchanging heat with the atmosphere, atmospheric components such as nitrogen and oxygen contained in the atmosphere are mixed into the coolant CW. The atmospheric components mixed into the coolant CW are mixed into the coolant CW1 and the coolant CWa described below.

[0024] [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 a coolant CW, more specifically, a coolant CWa that 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.

[0025] The mixed liquid MW discharged from the ejector 54 is sent to the gas separator 55. The mixed liquid MW and hot water HW sent to the reinjection well RWL are allowed to flow or are blocked by a valve 82.

[0026] (Ejector 54) The following describes the structure of the ejector 54. Fig. 2 is a diagram showing an outline of the configuration of the ejector 54 provided in the non-condensable gas reduction system 50, which is an example of the non-condensable gas reduction system according to the first embodiment.

[0027] The ejector 54 includes an induction section 51, a drive nozzle 52, and an expanded section 53. The induction section 51 has an induction port 51a. Non-condensable gas NCG is sucked in through the induction port 51a. The drive nozzle 52 is inserted into the induction section 51. Coolant CWa pressurized by a pump 92 is supplied to the drive port 52a of the drive nozzle 52. The coolant CWa is discharged at high speed from the tip of the drive nozzle 52, thereby discharging the non-condensable gas NCG present in the induction section 51 while mixing with the coolant CWa. As the non-condensable gas NCG is discharged, the ejector 54 sucks in the non-condensable gas NCG.

[0028] The ejector 54 mixes the non-condensable gas NCG with the coolant CWa, and discharges the mixed liquid MW through the expanded tube portion 53.

[0029] The non-condensable gas NCG and the coolant CWa are mixed in the ejector 54 and discharged as a mixed liquid MW, which is sent to the gas separator 55.

[0030] The ejector 54 is provided on the ground. Providing the ejector 54 on the ground facilitates maintenance of the ejector 54. Furthermore, by installing multiple ejectors, maintenance can be performed without stopping the system.

[0031] (Gas separator 55) The gas separator 55 separates atmospheric components AP contained in the mixed liquid MW and discharges it into the atmosphere. The gas separator 55 also discharges the remaining mixed liquid MWa from which the atmospheric components AP contained in the mixed liquid MW have been separated. The discharged mixed liquid MWa is mixed with hot water HW and sent to the reinjection well RWL. The gas separator 55 is connected downstream of the ejector 54.

[0032] The following describes in detail the gas separator 55. Fig. 3 is a diagram showing an outline of the configuration of the gas separator 55 provided in the non-condensable gas reduction system 50, which is an example of the non-condensable gas reduction system according to the first embodiment.

[0033] The gas separator 55 is a baffle-type gas separator. The gas separator 55 includes a tank 56, pipes 57a, 57b, 57c, and 57d, a level gauge 59a, and a gas purge valve 59b. The gas separator 55 is used in a state where there is a large amount of atmospheric components (gas-rich state). For example, the gas separator 55 is used when the Reynolds number calculated from the average flow velocity in the tank 56, the representative lateral length (e.g., diameter) of the tank 56, and the kinematic viscosity of the mixed liquid MW is 4000 or more.

[0034] The tank 56 separates and discharges the atmospheric component AP contained in the mixed liquid MW, and also discharges the mixed liquid MWe from which the atmospheric component AP has been reduced. The tank 56 is provided with a plurality of baffle plates 56e.

[0035] The multiple baffle plates 56e are arranged vertically side by side and alternately arranged horizontally inside the tank 56. By arranging the baffle plates 56e vertically side by side and alternately arranged horizontally inside the tank 56, the residence time of the mixed liquid MW that flows in from the inlet 56a inside the tank 56 is increased. Increasing the residence time of the mixed liquid MW that flows in from the inlet 56a inside the tank 56 can promote the growth of the bubble diameter of the bubbles BBL in the mixed liquid MW. When the bubble diameter of the bubbles BBL in the mixed liquid MW grows, the buoyancy of the bubbles BBL increases, and the mixed liquid MWa and the atmospheric component AP can be separated.

[0036] The separated atmospheric components AP are exhausted from the exhaust port 56b through the pipe 57a to the atmosphere. The gas separator 55 is provided with a gas purge valve 59b on the pipe 57a.

[0037] The mixed liquor MWe, in which the atmospheric components AP have been separated and the atmospheric components have been reduced, is discharged from the outlet 56c through the pipes 57c and 57d to the reinjection well RWL. The mixed liquor MWe is mixed with the hot water HW and discharged to the reinjection well RWL.

[0038] The pipe 57b is connected to the pipes 57a and 57c, thereby connecting the exhaust port 56b and the outlet port 56c. The pipe 57b connects the exhaust port 56b and the outlet port 56c, thereby equalizing the pressure in the drain line that discharges the mixed liquid MWa.

[0039] The level gauge 59a measures the liquid level of the mixed liquid MW inside the tank 56. The gas purge valve 59b is controlled in accordance with the liquid level measured by the level gauge 59a. The gas purge valve 59b opens or closes based on the liquid level measured by the level gauge 59a.

[0040] 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 external input / output interface device. The processor is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an MPU (Micro Processing Unit). The control device 58 may be, for example, a programmable logic controller (PLC).

[0041] During power generation, when the pressure P1 on the pressure gauge 71 becomes higher than the pressure P2 on the pressure gauge 73, the control device 58 controls the valve 83 to close so as to prevent the hot water HW from flowing to the condenser 30. The valve 83 is provided in the flow path through which the non-condensable gas NCG flows between the condenser 30 and the ejector 54. The pressure P1 on the pressure gauge 71 is the pressure of the hot water HW, and the pressure P2 on the pressure gauge 73 is the discharge pressure of the pump 92.

[0042] The control device 58 may also use a pressure gauge 72 to monitor the pressure of the non-condensable gas NCG.

[0043] The following describes the processing of the gas separator 55 executed by the control device 58. Fig. 4 is a flow diagram illustrating the processing of the noncondensable gas reduction system 50, which is an example of the noncondensable gas reduction system according to the first embodiment.

[0044] (Step S11) First, the control device 58 determines whether the liquid level measured by the level gauge 59a is lower than a threshold value. The control device 58 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is lower than the threshold value (YES in step S11), the control device 58 proceeds to the process of step S12. If the liquid level measured by the level gauge 59a is higher than or equal to the threshold value (NO in step S11), the control device 58 repeats the process of step S11.

[0045] (Step S12) If the liquid level measured by the liquid level gauge 59a is lower than the threshold value (YES in step S11), the control device 58 controls the gas purge valve 59b to open. When the gas purge valve 59b is opened, the atmospheric component AP passes through the gas purge valve 59b and is discharged into the atmosphere. When the atmospheric component AP is discharged, the liquid level of the mixed liquid MW in the tank 56 rises.

[0046] (Step S13) Next, the control device 58 determines whether the liquid level measured by the level gauge 59a is higher than a threshold value. The control device 58 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the threshold value (YES in step S13), the control device 58 proceeds to the process of step S14. If the liquid level measured by the level gauge 59a is lower than or equal to the threshold value (NO in step S13), the control device 58 returns to step S12 and repeats the process. Note that the threshold value in step S13 may be equal to or different from the threshold value in step S11.

[0047] (Step S14) If the liquid level measured by the liquid level gauge 59a is higher than the threshold value (YES in step S13), the control device 58 controls the gas purge valve 59b to close.

[0048] (Step S15) Next, the control device 58 determines whether or not to repeat the process. If the process is to be repeated (YES in step S15), the control device 58 returns to step S11 and repeats the process. If the process is not to be repeated, in other words, if the process is to be ended (NO in step S15), the control device 58 ends the process.

[0049] [Control unit 60] The control unit 60 controls the entire geothermal power plant 1. The control unit 60 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, a GPU, or an MPU. The control unit 60 may be, for example, a programmable logic controller.

[0050] 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 it.

[0051] According to the non-condensable gas reduction system of the first embodiment, by providing a gas separator downstream of the ejector, the atmospheric components contained in the gas reduced to the reduction well can be reduced, thereby suppressing the effects of the atmospheric components.

[0052] Second Embodiment A 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 configured such that a cyclone gas separator is used as the gas separator instead of the baffle gas separator in the non-condensable gas reduction system according to the first embodiment.

[0053] The configuration of the gas separator included in the noncondensable gas reduction system according to the second embodiment will be described. FIGS. 5 and 6 are diagrams showing an outline of the configuration of a gas separator 155, which is an example of a gas separator included in the noncondensable gas reduction system according to the second embodiment. FIG. 6 is a diagram showing the flow of the mixed liquid MW inside the tank 156 as viewed from above. Note that, apart from the gas separator 155, the configuration is common to the noncondensable gas reduction system according to the first embodiment, and therefore the description thereof will be omitted here and reference should be made to the description of the noncondensable gas reduction system according to the first embodiment.

[0054] (Gas separator 155) The gas separator 155 separates the atmospheric components AP contained in the mixed liquid MW and discharges it into the atmosphere. The gas separator 155 also discharges the remaining mixed liquid MWa from which the atmospheric components AP contained in the mixed liquid MW have been separated. The discharged mixed liquid MWa is mixed with hot water HW and sent to the reinjection well RWL. The gas separator 155 is connected downstream of the ejector 54.

[0055] The gas separator 155 is a cyclone gas separator. The gas separator 155 includes a tank 156, pipes 157a and 157b, a liquid level gauge 159a, and a gas purge valve 159b. The gas separator 155 is used in a state where the atmospheric components are low (liquid-rich state). For example, the gas separator 155 is used when the Reynolds number calculated from the average flow velocity in the tank 156, the representative lateral length (e.g., diameter) of the tank 156, and the kinematic viscosity of the mixed liquid MW is less than 4000.

[0056] The tank 156 separates and discharges the atmospheric component AP contained in the mixed solution MW, and also discharges the mixed solution MWa in which the atmospheric component AP has been reduced from the mixed solution MW. The tank 156 is provided therein with a rotation stopper 156e.

[0057] The swirl stopper 156e is provided at the bottom of the tank 156. The swirl stopper 156e is provided so that the generated vortex does not reach the bottom of the tank 156. The swirl stopper 156e may be formed, for example, by arranging plate members in a grid pattern, or by arranging a plurality of cylinders.

[0058] As shown in Fig. 6, in the tank 156, the mixed liquid MW that flows in from the inlet 156a swirls inside the tank 156 along the arrow B1. When the mixed liquid MW swirls inside the tank 156 along the arrow B1, the low-density gas components contained in the mixed liquid MW move toward the center as shown by the arrow A1. Furthermore, when the mixed liquid MW swirls inside the tank 156 along the arrow B1, the high-density liquid components contained in the mixed liquid MW move toward the outside as shown by the arrow A2. As shown by the arrows A1 and A2, the gas and liquid move in different directions when swirling inside the tank 156, and therefore the gas separator 155 can separate the atmospheric component AP from the mixed liquid MWa, which is the mixed liquid MW with the atmospheric component AP reduced.

[0059] The separated atmospheric components AP are exhausted from the exhaust port 156b through the pipe 157a into the atmosphere. The gas separator 155 is provided with a gas purge valve 159b on the pipe 157a.

[0060] The mixed solution MWa, in which the atmospheric components AP have been separated and the atmospheric components have been reduced, is discharged from the outlet 156c through the pipe 157b to the reinjection well RWL. The mixed solution MWa is mixed with the hot water HW and discharged to the reinjection well RWL.

[0061] The liquid level gauge 159a measures the liquid level of the mixed liquid MW inside the tank 156. The liquid level gauge 159a controls the gas purge valve 159b in accordance with the liquid level. The gas purge valve 159b opens or closes based on the liquid level measured by the liquid level gauge 159a.

[0062] In the control device 158 in the non-condensable gas reduction system equipped with the gas separator 155, a liquid level gauge 159a is connected to the control device 58 instead of the liquid level gauge 59a. The control device 158 also controls the gas purge valve 159b instead of the gas purge valve 59b. Other than the above, the control device 158 has the same functions and configuration as the control device 58, and therefore, for detailed explanation, please refer to the explanation of the control device 58, and detailed explanation will be omitted here.

[0063] According to the non-condensable gas reduction system of the second embodiment, by providing a gas separator downstream of the ejector, the atmospheric components contained in the gas reduced to the reduction well can be reduced, thereby suppressing the effects of the atmospheric components.

[0064] Third Embodiment A non-condensable gas reduction system according to a third embodiment will be described. For example, in the non-condensable gas reduction system according to the first embodiment, the gas separated in the gas separator may contain non-condensable gases such as carbon dioxide or hydrogen sulfide. The non-condensable gas reduction system according to the third embodiment performs alkali spraying and alkali scrubbing to purify acidic gases when the gas separated in the gas separator is released into the atmosphere in the non-condensable gas reduction system according to the first embodiment.

[0065] The configuration of the gas separator included in the noncondensable gas reduction system according to the third embodiment will be described. Fig. 7 is a diagram showing an outline of the configuration of a gas separator 255, which is an example of a gas separator included in the noncondensable gas reduction system according to the third embodiment. Note that, except for the gas separator 255, the configuration is common to the noncondensable gas reduction system according to the first embodiment, and therefore the description of the noncondensable gas reduction system according to the first embodiment should be referred to, and the description will be omitted here.

[0066] (Gas separator 255) The gas separator 255 further includes a chemical tank 260, a chemical injection pump 261, and a nozzle 262 in addition to the components of the gas separator 55. The non-condensable gas reduction system including the gas separator 255 also includes a control device 258 instead of the control device 58.

[0067] The chemical tank 260 stores an alkaline liquid to be sprayed, such as an aqueous sodium chloride solution. The chemical tank 260 is a so-called alkaline tank.

[0068] The chemical feed pump 261 supplies the alkaline solution from the chemical solution tank 260 to the nozzle 262. The chemical feed pump 261 is controlled based on the result of measurement of the liquid level by the liquid level gauge 59a.

[0069] The nozzle 262 sprays the alkaline liquid supplied from the chemical tank 260 onto the gas exhausted from the exhaust port 56b. The nozzle 262 is provided on the pipe 57a.

[0070] The following describes the processing of the gas separator 255 executed by the control device 258. Fig. 8 is a flow diagram illustrating the processing of the control device 258 in the non-condensable gas reduction system, which is an example of the non-condensable gas reduction system according to the third embodiment.

[0071] (Step S21) First, the control device 258 determines whether the liquid level measured by the level gauge 59a is lower than a threshold value. The control device 258 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is lower than the threshold value (YES in step S21), the control device 258 proceeds to the process in step S22. If the liquid level measured by the level gauge 59a is higher than or equal to the threshold value (NO in step S21), the control device 258 returns to step S21 and repeats the process.

[0072] (Step S22) If the liquid level measured by the level gauge 59a is lower than the threshold value (YES in step S21), the control device 258 controls the gas purge valve 59b to open. The control device 258 also controls the chemical feed pump 261 to start. When the chemical feed pump 261 is started, non-condensable gases such as carbon dioxide and hydrogen sulfide contained in the gas discharged from the tank 56 are cleaned. Then, when the gas purge valve 59b is opened, the atmospheric component AP is discharged into the atmosphere through the gas purge valve 59b. When the atmospheric component AP is discharged, the liquid level of the mixed liquid MW in the tank 56 rises.

[0073] (Step S23) Next, the control device 258 determines whether the liquid level measured by the level gauge 59a is higher than a threshold value. The control device 258 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the threshold value (YES in step S23), the control device 258 proceeds to the process of step S24. If the liquid level measured by the level gauge 59a is lower than or equal to the threshold value (NO in step S23), the control device 258 returns to step S22 and repeats the process. Note that the threshold value in step S23 may be equal to or different from the threshold value in step S21.

[0074] (Step S24) If the liquid level measured by the level gauge 59a is higher than the threshold value (YES in step S23), the control device 258 controls the gas purge valve 59b to close. Also, if the liquid level measured by the level gauge 59a is higher than the threshold value (YES in step S23), the control device 258 controls the chemical injection pump 261 to stop.

[0075] (Step S25) Next, the control device 258 determines whether or not to repeat the process. If the process is to be repeated (YES in step S25), the control device 258 returns to step S21 and repeats the process. If the process is not to be repeated, in other words, if the process is to be ended (NO in step S25), the control device 258 ends the process.

[0076] According to the non-condensable gas reduction system of the third embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce the atmospheric components contained in the gas reduced to the reduction well and suppress the effects of the atmospheric components. Furthermore, according to the non-condensable gas reduction system of the third embodiment, if non-condensable gas is contained in the gas separated by the gas separator, the non-condensable gas can be reduced.

[0077] The chemical tank 260, the chemical injection pump 261, and the nozzle 262 are an example of a chemical spraying unit.

[0078] Fourth Embodiment A non-condensable gas reduction system according to a fourth embodiment will be described. For example, in the non-condensable gas reduction system according to the second embodiment, the gas separated in the gas separator may contain non-condensable gases such as carbon dioxide or hydrogen sulfide. The non-condensable gas reduction system according to the fourth embodiment performs alkali spraying and alkali scrubbing to purify acidic gases when the gas separated in the gas separator is released into the atmosphere in the non-condensable gas reduction system according to the second embodiment.

[0079] The configuration of the gas separator included in the noncondensable gas reduction system according to the fourth embodiment will be described. FIG. 9 is a diagram showing an outline of the configuration of gas separator 355, which is an example of a gas separator included in the noncondensable gas reduction system according to the fourth embodiment. The gas separator 355, which is an example of a gas separator included in the noncondensable gas reduction system according to the fourth embodiment, will be used for the description. Since the configurations other than the gas separator 355 are common to the noncondensable gas reduction system according to the second embodiment, the description of the noncondensable gas reduction system according to the second embodiment can be referred to and the description thereof will be omitted here.

[0080] (Gas Separator 355) The gas separator 355 further includes a chemical tank 360, a chemical injection pump 361, and a nozzle 362 in addition to the components of the gas separator 155. The non-condensable gas reduction system including the gas separator 355 also includes a control device 358 instead of the control device 158.

[0081] The gas separator 355 differs from the gas separator 255 in that it is a cyclone type gas separator while the gas separator 255 is a baffle type gas separator. For details of the gas separator 355, please refer to the descriptions of the gas separator 55, the gas separator 155 and the gas separator 255.

[0082] According to the non-condensable gas reduction system of the fourth embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce atmospheric components contained in the gas reduced to the reduction well and suppress the effects of atmospheric components. Furthermore, according to the non-condensable gas reduction system of the fourth embodiment, if non-condensable gas is contained in the gas separated by the gas separator, the non-condensable gas can be reduced.

[0083] The chemical tank 360, the chemical injection pump 361, and the nozzle 362 are an example of a chemical spraying unit.

[0084] 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 third embodiment, the gas separated in the gas separator is returned to the ejector according to the concentration of carbon dioxide, which is a non-condensable gas.

[0085] The configuration of the gas separator included in the noncondensable gas reduction system according to the fifth embodiment will be described. FIG. 10 is a diagram showing an outline of the configuration of a gas separator 455, which is an example of a gas separator included in the noncondensable gas reduction system according to the fifth embodiment. Note that, since the configurations other than the gas separator 455 are common to those of the noncondensable gas reduction system according to the first embodiment, the description of the noncondensable gas reduction system according to the first embodiment should be referred to and a description thereof will be omitted here. Furthermore, in the noncondensable gas reduction system according to the fifth embodiment, a baffle-type gas separator will be used as the gas separator, but a cyclone-type gas separator may also be used.

[0086] (Gas separator 455) The gas separator 455 further includes a gas recycle valve 463 in addition to the gas separator 255. The gas recycle valve 463 is connected to the ejector 54 via a check valve 464. The gas EG2 that has passed through the gas recycle valve 463 is combined with the non-condensable gas NCG and is again sucked into the ejector 54. In order to prevent backflow, a check valve 465 is provided in the piping through which the non-condensable gas NCG flows. The gas separator 455 includes a carbon dioxide concentration analyzer 466.

[0087] The processing of the gas separator 455 executed by the control device 458 will be described. Fig. 11 is a flow diagram illustrating the processing of the control device 458 in a noncondensable gas reduction system, which is an example of a noncondensable gas reduction system according to the fifth embodiment. In the following description, it is assumed that the first threshold value is the lowest, the second threshold value is the highest, and the third threshold value is a value between the first threshold value and the second threshold value.

[0088] (Step S101) First, the control device 458 determines whether the liquid level measured by the level gauge 59a is lower than a first threshold value. The control device 458 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is lower than the first threshold value (YES in step S101), the control device 458 proceeds to the process in step S102. If the liquid level measured by the level gauge 59a is higher than or equal to the first threshold value (NO in step S101), the control device 458 returns to step S101 and repeats the process. If the liquid level measured by the level gauge 59a is higher than or equal to the first threshold value (NO in step S101), it is considered to be in a stable state.

[0089] (Step S102) If the liquid level measured by the liquid level gauge 59a is lower than the first threshold value (YES in step S101), the control device 458 determines whether the carbon dioxide concentration is low. The control device 458 acquires the carbon dioxide concentration measured by the carbon dioxide concentration analyzer 466. If the acquired carbon dioxide concentration is low (YES in step S102), for example, if the acquired carbon dioxide concentration is lower than a predetermined threshold value, the control device 458 proceeds to step S103. If the acquired carbon dioxide concentration is higher or equal (NO in step S102), the control device 458 proceeds to step S111.

[0090] (Step S103) The control device 458 controls the gas purge valve 59b to open. The control device 458 also controls the chemical feed pump 261 to start. When the chemical feed pump 261 is started, non-condensable gases such as carbon dioxide and hydrogen sulfide contained in the gas discharged from the tank 56 are cleaned. Then, when the gas purge valve 59b is opened, the atmospheric component AP is discharged into the atmosphere through the gas purge valve 59b. When the atmospheric component AP is discharged, the liquid level of the mixed liquid MW in the tank 56 rises.

[0091] (Step S104) Next, the control device 458 determines whether the liquid level measured by the level gauge 59a is higher than a second threshold value. The control device 458 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S104), the control device 458 proceeds to the process in step S105. If the liquid level measured by the level gauge 59a is lower than or equal to the second threshold value (NO in step S104), the control device 458 returns to step S104 and repeats the process.

[0092] (Step S105) If the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S104), the control device 458 controls the gas purge valve 59b to close. Also, if the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S104), the control device 458 controls the chemical injection pump 261 to stop.

[0093] (Step S106) Next, the control device 458 determines whether to repeat the process. If the process is to be repeated (YES in step S106), the control device 458 returns to step S101 and repeats the process. If the process is not to be repeated, in other words, if the process is to be ended (NO in step S106), the control device 458 ends the process.

[0094] (Step S111) In step S102, if the acquired carbon dioxide concentration is higher or equal (NO in step S102), it is considered that the carbon dioxide is not fully dissolved. In step S102, if the acquired carbon dioxide concentration is higher or equal (NO in step S102), the control device 458 controls the gas recycle valve 463 to open.

[0095] (Step S112) Next, the control device 458 determines whether the liquid level measured by the level gauge 59a is higher than a third threshold value. The control device 458 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the third threshold value (YES in step S112), the control device 458 proceeds to the process of step S113. If the liquid level measured by the level gauge 59a is lower than or equal to the third threshold value (NO in step S112), the control device 458 proceeds to the process of step S121.

[0096] (Step S113) In step S112, if the liquid level measured by the liquid level gauge 59a is higher than the third threshold value (YES in step S112), the control device 458 controls to close the gas recycle valve 463. Then, the control device 458 advances the process to step S106.

[0097] (Step S121) In step S112, if the liquid level measured by the liquid level gauge 59a is lower than or equal to the third threshold value (NO in step S112), it is considered that the dissolution promotion effect is weak and it is highly likely that carbon dioxide has not dissolved. In step S112, if the liquid level measured by the liquid level gauge 59a is lower than or equal to the third threshold value (NO in step S112), the control device 458 determines whether the carbon dioxide concentration is low. The control device 458 acquires the carbon dioxide concentration measured by the carbon dioxide concentration analyzer 466. If the acquired carbon dioxide concentration is low (YES in step S121), for example, if the acquired carbon dioxide concentration is lower than a predetermined threshold value, the control device 458 proceeds to step S122. If the acquired carbon dioxide concentration is higher than or equal to the third threshold value (NO in step S121), the control device 458 proceeds to step S131.

[0098] (Step S122) In step S121, if the carbon dioxide concentration is low (YES in step S121), the control device 458 controls to close the gas recycle valve 463. Then, the control device 458 advances the process to step S106.

[0099] (Step S131) In step S121, if the carbon dioxide concentration is higher or equal (NO in step S121), it is considered that the promotion of dissolution cannot be confirmed. In step S121, if the carbon dioxide concentration is higher or equal (NO in step S121), the control device 458 controls the chemical injection pump 261 to start.

[0100] (Step S132) The control device 458 determines whether the carbon dioxide concentration is low. The control device 458 acquires the carbon dioxide concentration measured by the carbon dioxide concentration analyzer 466. If the acquired carbon dioxide concentration is low (YES in step S132), the control device 458 proceeds to the process in step S133. If the acquired carbon dioxide concentration is higher or equal (NO in step S132), the control device 458 repeats the process in step S132 to forcibly dissolve the carbon dioxide.

[0101] (Step S133) In step S132, if the carbon dioxide concentration is low (YES in step S132), the control device 458 controls the chemical injection pump 261 to stop.

[0102] (Step S134) Next, the control device 458 determines whether the liquid level measured by the level gauge 59a is higher than a third threshold value. The control device 458 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the third threshold value (YES in step S134), the control device 458 proceeds to the process of step S135. If the liquid level measured by the level gauge 59a is lower than or equal to the third threshold value (NO in step S134), the control device 458 proceeds to the process of step S136.

[0103] (Step S135) In step S134, if the liquid level measured by the liquid level gauge 59a is higher than the third threshold value (YES in step S134), the control device 458 controls to close the gas recycle valve 463. Then, the control device 458 advances the process to step S106.

[0104] (Step S136) In step S134, if the liquid level measured by level gauge 59a is lower than or equal to the third threshold value (NO in step S134), control device 458 controls to close gas recycle valve 463. Then, control device 458 advances the process to step S103.

[0105] According to the non-condensable gas reduction system of the fifth embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce atmospheric components contained in the gas reduced to the reduction well and suppress the effects of atmospheric components. Furthermore, according to the non-condensable gas reduction system of the fifth embodiment, if the gas separated by the gas separator contains non-condensable gas, the non-condensable gas can be reduced. Furthermore, according to the non-condensable gas reduction system of the fifth embodiment, if the gas separated by the gas separator contains non-condensable gas, the non-condensable gas can be recycled.

[0106] The carbon dioxide concentration analyzer 466 is an example of a measurement unit, and the chemical tank 260, the chemical injection pump 261, and the nozzle 262 are an example of a chemical spray unit.

[0107] Sixth Embodiment A non-condensable gas reduction system according to a sixth embodiment will be described. The non-condensable gas reduction system according to the sixth embodiment is the same as the non-condensable gas reduction system according to the fifth embodiment, except that the gas separated in the gas separator is returned to the ejector according to the concentration of hydrogen sulfide, which is a non-condensable gas.

[0108] The configuration of the gas separator included in the non-condensable gas reduction system according to the sixth embodiment will be described. FIG. 12 is a diagram showing an outline of the configuration of gas separator 555, which is an example of a gas separator included in the non-condensable gas reduction system according to the sixth embodiment. Note that, since the configurations other than gas separator 555 are common to those of the non-condensable gas reduction system according to the first embodiment, the description of the non-condensable gas reduction system according to the first embodiment should be referred to and the description will be omitted here. Furthermore, in the non-condensable gas reduction system according to the sixth embodiment, a baffle-type gas separator will be used as the gas separator, but a cyclone-type gas separator may also be used.

[0109] (Gas Separator 555) The gas separator 455 further includes a hydrogen sulfide concentration analyzer 565. The gas recycle valve 463 is connected to the ejector 54 via a check valve 464. The gas EG2 that has passed through the gas recycle valve 463 merges with the non-condensable gas NCG and is sucked into the ejector 54. In order to prevent backflow, a check valve 465 is provided in the piping through which the non-condensable gas NCG flows. The gas separator 455 includes a carbon dioxide concentration analyzer 466.

[0110] The processing of the gas separator 555 executed by the control device 558 will be described. Fig. 13 is a flow diagram illustrating the processing of the control device 558 in the noncondensable gas reduction system, which is an example of the noncondensable gas reduction system according to the sixth embodiment. In the following description, it is assumed that the first threshold value is the lowest, the second threshold value is the highest, and the third threshold value is between the first threshold value and the second threshold value.

[0111] (Step S201) First, the control device 558 determines whether the liquid level measured by the level gauge 59a is lower than a first threshold value. The control device 558 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is lower than the first threshold value (YES in step S201), the control device 558 proceeds to the process of step S202. If the liquid level measured by the level gauge 59a is higher than or equal to the first threshold value (NO in step S201), the control device 558 repeats the process of step S201. If the liquid level measured by the level gauge 59a is higher than or equal to the first threshold value (NO in step S201), it is considered to be in a stable state.

[0112] (Step S202) If the liquid level measured by the liquid level gauge 59a is lower than the first threshold value (YES in step S201), the control device 558 determines whether the carbon dioxide concentration is low. The control device 558 acquires the carbon dioxide concentration measured by the carbon dioxide concentration analyzer 466. If the acquired carbon dioxide concentration is low (YES in step S202), for example, if the acquired carbon dioxide concentration is lower than a predetermined threshold value, the control device 558 proceeds to step S203. If the acquired carbon dioxide concentration is higher or equal (NO in step S202), the control device 558 proceeds to step S211.

[0113] (Step S203) If the acquired carbon dioxide concentration is low (YES in step S202), the control device 558 determines whether the hydrogen sulfide concentration is low. The control device 558 acquires the hydrogen sulfide concentration measured from the hydrogen sulfide concentration analyzer 565. If the acquired hydrogen sulfide concentration is low (YES in step S203), for example, if the acquired hydrogen sulfide concentration is lower than a predetermined threshold, the control device 558 proceeds to step S204. If the acquired hydrogen sulfide concentration is higher or equal (NO in step S203), the control device 558 proceeds to step S241.

[0114] (Step S204) The control device 558 controls the gas purge valve 59b to open. When the gas purge valve 59b is opened, the atmospheric component AP is discharged into the atmosphere through the gas purge valve 59b. When the atmospheric component AP is discharged, the liquid level of the mixed liquid MW in the tank 56 rises.

[0115] (Step S205) Next, the control device 558 determines whether the liquid level measured by the level gauge 59a is higher than a second threshold value. The control device 558 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S205), the control device 558 proceeds to the process of step S206. If the liquid level measured by the level gauge 59a is lower than or equal to the second threshold value (NO in step S205), the control device 558 repeats the process of step S205.

[0116] (Step S206) If the liquid level measured by the liquid level gauge 59a is higher than the second threshold value (YES in step S205), the control device 558 controls the gas purge valve 59b to close.

[0117] (Step S207) Next, the control device 558 determines whether or not to repeat the process. If the process is to be repeated (YES in step S207), the control device 558 returns to step S201 and repeats the process. If the process is not to be repeated, in other words, if the process is to be ended (NO in step S207), the control device 558 ends the process.

[0118] (Step S211) In step S202, if the acquired carbon dioxide concentration is higher or equal (NO in step S202), it is considered that the carbon dioxide is not fully dissolved. In step S202, if the acquired carbon dioxide concentration is higher or equal (NO in step S202), the control device 558 controls the gas recycle valve 463 to open.

[0119] (Step S212) Next, the control device 558 determines whether the liquid level measured by the level gauge 59a is higher than a third threshold value. The control device 558 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the third threshold value (YES in step S212), the control device 558 proceeds to the process of step S213. If the liquid level measured by the level gauge 59a is lower than or equal to the third threshold value (NO in step S212), the control device 558 proceeds to the process of step S221.

[0120] (Step S213) In step S212, if the liquid level measured by the liquid level gauge 59a is higher than the third threshold value (YES in step S212), the control device 558 controls to close the gas recycle valve 463. Then, the control device 558 advances the process to step S207.

[0121] (Step S221) In step S212, if the liquid level measured by the liquid level gauge 59a is lower than or equal to the third threshold value (NO in step S212), it is considered that the dissolution promotion effect is weak and it is highly likely that carbon dioxide has not dissolved. In step S212, if the liquid level measured by the liquid level gauge 59a is lower than or equal to the third threshold value (NO in step S212), the control device 558 determines whether the carbon dioxide concentration is low. The control device 558 acquires the carbon dioxide concentration measured by the carbon dioxide concentration analyzer 466. If the acquired carbon dioxide concentration is low (YES in step S221), for example, if the acquired carbon dioxide concentration is lower than a predetermined threshold value, the control device 558 proceeds to step S222. If the acquired carbon dioxide concentration is higher than or equal to the third threshold value (NO in step S221), the control device 558 proceeds to step S231.

[0122] (Step S222) In step S221, if the carbon dioxide concentration is low (YES in step S221), the control device 558 controls to close the gas recycle valve 463. Then, the control device 558 advances the process to step S203.

[0123] (Step S231) In step S221, if the carbon dioxide concentration is higher or equal (NO in step S221), it is considered that the promotion of dissolution cannot be confirmed. In step S221, if the carbon dioxide concentration is higher or equal (NO in step S221), the control device 558 controls the chemical injection pump 261 to start.

[0124] (Step S232) The control device 558 determines whether the carbon dioxide concentration is low. The control device 558 acquires the carbon dioxide concentration measured by the carbon dioxide concentration analyzer 466. If the acquired carbon dioxide concentration is low (YES in step S232), the control device 558 proceeds to step S233. If the acquired carbon dioxide concentration is higher or equal (NO in step S232), the control device 558 repeats the process of step S232 to forcibly dissolve the carbon dioxide.

[0125] (Step S233) In step S232, if the carbon dioxide concentration is low (YES in step S232), the control device 558 controls the chemical injection pump 261 to stop.

[0126] (Step S234) Next, the control device 558 determines whether the liquid level measured by the level gauge 59a is higher than a third threshold value. The control device 558 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the third threshold value (YES in step S234), the control device 558 proceeds to step S235. If the liquid level measured by the level gauge 59a is lower than or equal to the third threshold value (NO in step S234), the control device 558 proceeds to step S236.

[0127] (Step S235) In step S234, if the liquid level measured by the liquid level gauge 59a is higher than the third threshold value (YES in step S234), the control device 558 controls to close the gas recycle valve 463. Then, the control device 558 advances the process to step S207.

[0128] (Step S236) In step S234, if the liquid level measured by level gauge 59a is lower than or equal to the third threshold value (NO in step S234), control device 558 controls to close gas recycle valve 463. Then, the process proceeds to step S203.

[0129] (Step S241) In step S203, if the hydrogen sulfide concentration is higher or equal (NO in step S203), the control device 558 controls the gas purge valve 59b to open. The control device 558 also controls the chemical feed pump 261 to start. When the chemical feed pump 261 is started, non-condensable gases such as carbon dioxide and hydrogen sulfide contained in the gas discharged from the tank 56 are cleaned. Then, when the gas purge valve 59b is opened, the atmospheric component AP is discharged into the atmosphere through the gas purge valve 59b. When the atmospheric component AP is discharged, the liquid level of the mixed solution MW in the tank 56 rises.

[0130] (Step S242) Next, the control device 558 determines whether the liquid level measured by the level gauge 59a is higher than a second threshold value. The control device 558 acquires the measurement result of the liquid level of the mixed liquid MW in the tank 56 from the level gauge 59a. Then, if the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S242), the control device 558 proceeds to the process of step S243. If the liquid level measured by the level gauge 59a is lower than or equal to the second threshold value (NO in step S242), the control device 558 repeats the process of step S242.

[0131] (Step S243) If the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S242), the control device 558 controls the gas purge valve 59b to close. Also, if the liquid level measured by the level gauge 59a is higher than the second threshold value (YES in step S242), the control device 558 controls the chemical injection pump 261 to stop. Then, the control device 558 advances the process to step S207.

[0132] According to the non-condensable gas reduction system of the sixth embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce atmospheric components contained in the gas reduced to the reduction well and suppress the effects of atmospheric components. Furthermore, according to the non-condensable gas reduction system of the sixth embodiment, if the gas separated by the gas separator contains non-condensable gas, the non-condensable gas can be reduced. Furthermore, according to the non-condensable gas reduction system of the sixth embodiment, if the gas separated by the gas separator contains non-condensable gas, the non-condensable gas can be recycled.

[0133] The carbon dioxide concentration analyzer 466 or the hydrogen sulfide concentration analyzer 565 is an example of a measurement unit, and the chemical tank 260, the chemical injection pump 261, and the nozzle 262 are an example of a chemical spray unit.

[0134] Seventh Embodiment A non-condensable gas reduction system according to the seventh embodiment will now be described. A geothermal power plant equipped with the non-condensable gas reduction system according to the seventh embodiment further includes a reduction pit for storing a first liquid. In the non-condensable gas reduction system according to the seventh embodiment, the liquid stored in the reduction pit is supplied to the ejector.

[0135] Next, the non-condensable gas reduction system according to the seventh embodiment will be described in detail with reference to the drawings. Fig. 14 is a diagram showing an outline of the configuration of a geothermal power plant 2 equipped with a non-condensable gas reduction system 650, which is an example of the non-condensable gas reduction system according to the seventh embodiment.

[0136] Geothermal power plant 2 includes gas-liquid separator 10, power generation unit 20, condenser 30, cooling unit 40, non-condensable gas reduction system 650, and control unit 660. Geothermal power plant 2 also includes valves 81 and 82, pumps 91 and 693, and reduction pit 611. Control unit 660 has the same functions as control unit 60.

[0137] Regarding the configuration of the geothermal power plant 2 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.

[0138] The geothermal power plant 2 includes a reduction pit 611 that stores the hot water HW discharged from the gas-liquid separator 10. The hot water HW stored in the reduction pit 611 is sent to the reduction well RWL by a pump 693. In addition, hot water HWb, which is a portion of the hot water HW stored in the reduction pit 611, is pressurized by a pump 692 and supplied to the ejector 54. The reduction pit 611 may be a tank or a pool.

[0139] The non-condensable gas reduction system 650 includes an ejector 54, a gas separator 55, a control device 658, a pressure gauge 671, a pressure gauge 72, and a pressure gauge 73, a valve 83, and a pump 692. The non-condensable gas reduction system 650 measures the pressure P1 of the hot water HW using a pressure gauge 671 instead of the pressure gauge 71 in the non-condensable gas reduction system 50. The control device 658 has the same function and configuration as the control device 58. The non-condensable gas reduction system 650 pressurizes hot water HWb, which is part of the hot water HW stored in the reduction pit 611, using a pump 692 and supplies the pressurized water to the ejector 54.

[0140] The ejector 54 is driven by hot water HWb, which is a part of the hot water HW stored in the reduction pit 611. The hot water HWb is pumped by a pump 692. The ejector 54 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the hot water HWb.

[0141] The gas separator 55 separates the atmospheric components AP from the mixed liquid MW and discharges it into the atmosphere. Then, a mixed liquid MWa with the atmospheric components reduced from the mixed liquid MW is discharged. The discharged mixed liquid MWa is mixed with hot water HW and sent to the reinjection well RWL.

[0142] Atmospheric components may be mixed into the hot water HWb in the reduction pit 611. According to the non-condensable gas reduction system of the seventh embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce the atmospheric components contained in the gas reduced to the reduction well and suppress the effects of the atmospheric components.

[0143] It should be noted that the gas separators in the noncondensable gas reduction systems according to the second to sixth embodiments may be applied to the noncondensable gas reduction system according to the seventh embodiment.

[0144] Eighth Embodiment A non-condensable gas reduction system according to the eighth embodiment will be described. In the non-condensable gas reduction system according to the eighth embodiment, the condenser in the non-condensable gas reduction system according to the first embodiment is a direct contact condenser.

[0145] Next, the non-condensable gas reduction system according to the eighth embodiment will be described in detail with reference to the drawings. Fig. 15 is a diagram showing an outline of the configuration of a geothermal power plant 3 equipped with a non-condensable gas reduction system 850, which is an example of the non-condensable gas reduction system according to the eighth embodiment.

[0146] The geothermal power plant 3 includes a gas-liquid separator 10, a power generation unit 20, a condenser 830, a cooling unit 840, a non-condensable gas reduction system 850, and a control unit 860. The geothermal power plant 3 also includes a valve 81, a valve 82, a pump 91, and a pump 832. The control unit 860 has the same functions as the control unit 60.

[0147] Regarding the configuration of the geothermal power plant 3 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.

[0148] [Condenser 830] The condenser 830 cools the steam ST discharged from the turbine 21 with the coolant CWA, more specifically the coolant CWA1, supplied from the cooling unit 840. The condenser 830 is a so-called direct contact condenser. The condenser 830 includes a nozzle unit 831. The nozzle unit 831 includes a plurality of nozzles that spray the coolant CWA1 as a mist. Note that the nozzle unit 831 may include only one nozzle. The condenser 830 performs heat exchange with the steam ST by spraying the coolant CWA1 onto the steam ST and bringing it into direct contact. The steam ST is cooled by the heat exchange between the coolant CWA1 and the steam ST. The steam ST is cooled in the condenser 830, and condenses into water. In the condenser 830, which is a direct contact condenser, the coolant CWA1 comes into direct contact with the steam ST. The coolant CWA2 contains water condensed from the steam ST.

[0149] [Cooling section 840] The cooling unit 840 supplies coolant CWA to cool the steam ST in the condenser 830. The cooling unit 840 is a cooling tower. The pump 832 sends the coolant CWA2, which has been heated to a high temperature by cooling the steam ST in the condenser 830, to the cooling unit 840. The cooling unit 840 cools the coolant CWA2. The coolant CWA cooled in the cooling unit 840 is sent to the condenser 830 by the pump 91. The coolant CWA2, whose temperature has increased due to heat exchange with the steam ST in the condenser 830, returns to the cooling unit 840 and is cooled.

[0150] The cooling unit 840 is a forced draft wet cooling tower. The cooling unit 840 is a so-called wet cooler. The cooling unit 840 brings the coolant CWA2 into direct contact with the air. The cooling unit 840 cools the coolant CWA2 by the transfer of latent heat of evaporation and sensible heat of the coolant CWA2 when the coolant CWA2 comes into direct contact with the air. The cooling unit 840 is a suction counterflow cooling tower.

[0151] Cooling unit 840 includes fan 841, nozzle unit 842, and filler 843. Fan 841 exhausts outside air taken in through opening 840h. Nozzle unit 842 includes a plurality of nozzles that spray coolant CWA2 sent from condenser 830 onto filler 843 as a mist. Note that nozzle unit 842 may include only one nozzle.

[0152] As air passes through the filler 843, the coolant CWA2 sprayed from the nozzle portion 842 exchanges heat with the air.

[0153] The coolant CWA cooled in the cooling section 840 is supplied to the condenser 830 by a pump 91 .

[0154] In the above example, the cooling unit 840 is a suction-type counterflow cooling tower. However, the cooling unit of the non-condensable gas reduction system according to this embodiment is not limited to a suction-type counterflow cooling tower. For example, the cooling unit of the non-condensable gas reduction system according to this embodiment may be a forced draft counterflow cooling tower, a suction-type crossflow cooling tower, or a forced draft crossflow cooling tower. Furthermore, the cooling unit of the non-condensable gas reduction system according to this embodiment may be a natural draft cooling tower.

[0155] [Non-condensable gas reduction system 850] The non-condensable gas reduction system 850 attracts and discharges the non-condensable gas NCG from the condenser 830. The non-condensable gas reduction system 850 is driven by the coolant CWA, more specifically, by the coolant CWAa, which is a part of the coolant CWA1. The coolant CWAa is pressure-fed by the pump 92. The ejector 54 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the coolant CWAa. The non-condensable gas reduction system 850 includes the ejector 54, a control device 858, a pressure gauge 71, a pressure gauge 72, a pressure gauge 73, a valve 83, and a pump 92. The control device 858 has the same function and configuration as the control device 58.

[0156] The ejector 54 is driven by a coolant CWAa, which is a part of the coolant CWA1. The coolant CWAa contains water (second liquid) obtained by condensing steam ST in the condenser 830. The coolant CWAa is pumped by a pump 92. The ejector 54 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the coolant CWAa.

[0157] The ejector 54 mixes the non-condensable gas NCG with the coolant CWAa and discharges the mixed liquid MW.

[0158] The gas separator 55 separates the atmospheric components AP from the mixed liquid MW and discharges it into the atmosphere. Then, a mixed liquid MWa with the atmospheric components reduced from the mixed liquid MW is discharged. The discharged mixed liquid MWa is mixed with hot water HW and sent to the reinjection well RWL.

[0159] Atmospheric components may be mixed into the non-condensable gas NCG in the condenser 830. Also, atmospheric components may be mixed into the coolant CWA in the cooling section 840. According to the non-condensable gas reduction system of the eighth embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce the atmospheric components contained in the gas reduced to the reduction well and suppress the effects of the atmospheric components.

[0160] It should be noted that the gas separators in the noncondensable gas reduction systems according to the second to sixth embodiments may be applied to the noncondensable gas reduction system according to the eighth embodiment.

[0161] Ninth Embodiment A non-condensable gas reduction system according to a ninth embodiment will be described. The non-condensable gas reduction system according to a ninth embodiment is a non-condensable gas reduction system for use in a geothermal power plant that employs a so-called binary geothermal power generation system.

[0162] Next, the non-condensable gas reduction system according to the ninth embodiment will be described in detail with reference to the drawings. Fig. 16 is a diagram showing an outline of the configuration of a geothermal power plant 4 equipped with a non-condensable gas reduction system 950, which is an example of the non-condensable gas reduction system according to the ninth embodiment.

[0163] The geothermal power plant 4 includes a gas-liquid separator 10, a power generation unit 20, a condenser 930, an evaporator 35, a cooling unit 940, a non-condensable gas reduction system 950, and a control unit 960. The geothermal power plant 4 is a so-called binary geothermal power generation type geothermal power plant. The geothermal power plant 4 also includes a valve 81, a valve 82, a pump 91, and a pump 93.

[0164] Regarding the configuration of the geothermal power plant 4 that is common to the geothermal power plant 3, the description of the geothermal power plant 3 etc. should be referred to, and detailed description thereof will be omitted here.

[0165] [Power Generation Unit 20] The power generation unit 20 generates power 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 is rotated by the pressure difference between the working medium RF that has been turned from a liquid to a gas through heat exchange with the steam ST in the evaporator 35, and the working medium RF that has been cooled by the coolant CW1 in the condenser 930 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, generating power. The power generated by the generator 22 is supplied to the outside.

[0166] The working medium RF is a medium having a boiling point lower than that of water, such as ammonia, pentane, or a chlorofluorocarbon alternative. The working medium RF is condensed from a gas state into a liquid state by being cooled in the condenser 930. The working medium RF is evaporated from a liquid state into a gas state by being heated in the evaporator 35. The working medium RF is circulated by the pump 93 through the evaporator 35, the turbine 21, and the condenser 930 in this order.

[0167] [Condenser 930] The condenser 930 cools the working medium RF discharged from the turbine 21 with the coolant CWA supplied from the cooling unit 940. The working medium RF is condensed and changes from a gas state to a liquid state by being cooled in the condenser 930. The condenser 930 is, for example, a shell-and-tube heat exchanger, a plate-type heat exchanger, or the like.

[0168] [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. In the evaporator 35, heat is exchanged between the steam ST and the working medium RF, so that the steam ST is cooled. When the steam ST is cooled, the steam ST condenses into a condensed liquid HWa.

[0169] 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 condensed liquid HWa formed by condensing the steam ST in the evaporator 35 drops. When the liquid level of the condensed liquid HWa formed by condensing the steam ST drops in the evaporator 35, 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.

[0170] In the geothermal power plant 4, the non-condensable gas NCG accumulated in the evaporator 35 is attracted by the non-condensable gas reduction system 950 and discharged to the reinjection well RWL.

[0171] A level gauge 84 is provided in the evaporator 35. The level gauge 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 gauge 84 drops. Furthermore, in the evaporator 35, the condensate formed by condensing steam ST is discharged to the reinjection well RWL.

[0172] [Cooling section 940] The cooling unit 940 has the same configuration as the cooling unit 840, and therefore, for the configuration of the cooling unit 940, the description of the cooling unit 840 should be referred to, and a detailed description thereof will be omitted.

[0173] [Non-condensable gas reduction system 950] The non-condensable gas reduction system 950 attracts and discharges the non-condensable gas NCG from the evaporator 35. The non-condensable gas reduction system 950 is driven by the coolant CWA, more specifically, the coolant CWa, which is a part of the coolant CWA1. The coolant CWa is pressure-fed by the pump 92. The ejector 54 discharges a mixed liquid MW obtained by mixing the non-condensable gas NCG and the coolant CWa. The non-condensable gas reduction system 950 includes the ejector 54, a control device 958, a pressure gauge 71, a pressure gauge 72, a pressure gauge 73, a valve 83, and a pump 92. The control device 958 has the same function and configuration as the control device 58.

[0174] The ejector 54 is driven by the coolant CWa, which is a part of the coolant CWA1. Atmospheric components are mixed into the coolant CWa in the cooling section 940.

[0175] The gas separator 55 separates the atmospheric components AP from the mixed liquid MW and discharges it into the atmosphere. Then, a mixed liquid MWa with the atmospheric components reduced from the mixed liquid MW is discharged. The discharged mixed liquid MWa is mixed with hot water HW and sent to the reinjection well RWL.

[0176] Atmospheric components may become mixed into the cooling liquid CWA in the cooling section 940. According to the non-condensable gas reduction system of the ninth embodiment, by providing a gas separator downstream of the ejector, it is possible to reduce the atmospheric components contained in the gas reduced to the reduction well and suppress the effects of the atmospheric components.

[0177] It should be noted that the gas separators in the noncondensable gas reduction systems according to the second to sixth embodiments may be applied to the noncondensable gas reduction system according to the ninth embodiment.

[0178] [Relationship between bubble diameter and buoyancy] In a baffle-type gas separator, when the buoyancy of non-condensable gas bubbles exceeds the hot water flow velocity, the bubbles rise, coalesce, and accumulate at the top of the pipe as a gas phase. In the case of a gas separator, it is important to allow the bubbles to grow sufficiently and separate them using buoyancy. On the other hand, in vertical pipes such as reinjection wells, it is necessary to avoid problems caused by gas retention by designing the bubble diameter so that the bubble rising speed (terminal velocity of the bubbles) is smaller than the hot water flow velocity in the pipe.

[0179] Here, the allowable bubble diameter was investigated. The assumptions were that gas was injected into the injection line, the temperature of the injection hot water was 80°C, the pressure was 0.2 MPa (A), the bubble shape was spherical, and the liquid phase fluid flow velocity was 1 m / s.

[0180] The bubble diameter at which the terminal velocity of the bubble is 1 m / s or less was determined. The terminal velocity of the bubble as it sinks through the fluid was calculated using Stokes' equation from the buoyancy, gravity, and resistance forces acting on the bubble. Terminal velocity is the velocity at which the buoyancy force acting on the particle upward and the downward gravity force are balanced.

[0181] <Calculating terminal velocity ~ Stokes' equation> The physical properties and letter notations used in the calculation are shown below.

[0182] Water density [ρl]:971.84701383[kg / m 3 ] Water viscosity [η]: 0.00036 [kg / m s = Pa s] (atmospheric pressure value) Carbon dioxide density [ρg]: 3.014668 [kg / m 3 ] Vs: Terminal velocity [m / s] Φ: Particle diameter [mm] r: bubble radius [m] V: Bubble volume [m 3 ] g: Gravitational acceleration [m / s 2 ]: 9.80665 Fg:Gravity [N] Fb: Buoyancy [N]

[0183] When a bubble flows through a fluid, it is subjected to buoyancy, gravity, and drag. The drag force acting on a sphere falling through a fluid is shown in Equation 1.

[0184]

number

[0185] Since the bubble is spherical, the volume V is given by Equation 2.

[0186]

number

[0187] Therefore, the buoyancy force Fb satisfies Equation 3.

[0188]

number

[0189] Moreover, the gravity Fg satisfies Equation 4.

[0190]

number

[0191] When a particle falls through a fluid with terminal velocity vs, these forces balance. That is, drag force + buoyancy force = gravity, so terminal velocity v is given by Equation 5.

[0192]

number

[0193] When the bubble radius r was 0.0004 m, i.e., the bubble diameter Φ was 0.8 mm, the terminal velocity v was -0.94 m / s. Therefore, it was determined that the threshold value of the bubble diameter Φ at which the bubble rising velocity (buoyancy) is less than the hot water flow velocity in the pipe is 0.8 mm.

[0194] Furthermore, if the bubbles start to rise from the end of the baffle and grow so that they can escape to the top of the outlet within the distance from the end to the water outlet, the bubbles can be separated. Therefore, in a gas separator, gas can be separated by adjusting the residence time with the baffle.

[0195] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive, and the above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0196] 1, 2, 3, 4 Geothermal Power Plant 10 Gas-liquid separator 20 Power Generation Department 30 Condenser 35 Evaporator 40 Cooling section 50, 650, 850, 950 Non-condensable gas reduction system 54 Ejector 55, 155, 255, 355, 455, 555 Gas separator 59a, 159a Liquid level gauge 59b, 159b Gas purge valve 260, 360 chemical tank 261, 361 Chemical injection pump 262, 362 nozzles 463 Gas recycle valve 466 Carbon Dioxide Concentration Analyzer 565 Hydrogen Sulfide Concentration Analyzer 611 Reduction Pit 830 Condenser 840 Cooling section 858 Control Device 860 Control Unit 930 Condenser 940 Cooling section 958 Control Device 960 Control Unit CW, CW1, CW2, CWa, CWA, CWA1, CWA2, CWAa Coolant EG2 Gas GF geothermal fluid NCG Non-condensable gas PWL production well RF working medium RWL Reinjection Well ST Steam

Claims

1. A non-condensable gas reduction system in a geothermal power plant, which returns non-condensable gas that remains in a first gas contained in a geothermal fluid that springs from a production well and is not condensed when cooled to a reduction well, a pump that pressurizes the first liquid sent to the reinjection well; an ejector driven by the first liquid, attracting the non-condensable gas, and discharging a second liquid that is a mixture of the first liquid and the non-condensable gas; a gas separator connected downstream of the ejector, which separates a second gas containing atmospheric components mixed in the second liquid, and discharges the second gas into the atmosphere and the second liquid into the reinjection well; Equipped with Non-condensable gas reduction system.

2. the geothermal power plant includes a direct contact condenser that cools the first gas; The ejector draws the non-condensable gas remaining in the condenser without being condensed. The noncondensable gas reduction system of claim 1 .

3. The first liquid exchanges heat with the atmosphere in a wet cooler. The noncondensable gas reduction system of claim 1 .

4. The gas separator is a baffle-type gas separator or a cyclone-type gas separator; The non-condensable gas reduction system according to any one of claims 1 to 3.

5. The gas separator is provided with a level gauge for measuring the liquid level. The non-condensable gas reduction system according to any one of claims 1 to 3.

6. a valve that allows or blocks the second gas to flow based on the liquid level measured by the liquid level gauge; The noncondensable gas reduction system of claim 5 .

7. A chemical solution spraying unit that sprays an alkaline solution into the separated second gas is provided. The non-condensable gas reduction system according to any one of claims 1 to 3.

8. a measuring unit that measures the non-condensable gas contained in the second gas, The chemical solution spraying unit sprays the alkaline solution based on the measurement result of the measurement unit. The noncondensable gas reduction system of claim 7.

9. a measuring unit that measures the non-condensable gas contained in the second gas, The second gas is sucked into the ejector again based on the measurement result of the measurement unit. The non-condensable gas reduction system according to any one of claims 1 to 3.

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