Non-condensable gas reduction system

Abstract

This disclosure provides a technology for preventing ejector clogging when reducing noncondensable gases using an ejector in a geothermal power plant. [Solution] A non-condensable gas reduction system comprising: a pump that pressurizes a first liquid sent to a reduction well; a first pressure gauge that measures the pressure of the first liquid discharged from the pump; a first flow meter that measures the flow rate of the first liquid discharged from the pump; a second pressure gauge that measures the pressure of a non-condensable gas; a second flow meter that measures the flow rate of a non-condensable gas; an ejector driven by the first liquid supplied from a first port, which induces non-condensable gas from a second port and discharges a second liquid, a mixture of the first liquid and the non-condensable gas, from a third port; a third pressure gauge that measures the pressure of the second liquid; and a control device that diagnoses blockages in the first, second, and third ports based on the measurement results of the first pressure gauge, first flow meter, second pressure gauge, second flow meter, and third pressure gauge, respectively.

Description

Technical Field

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

Background Art

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

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

[0004] ; Patent Document 3 discloses a non-condensable gas reduction system used in a so-called binary geothermal power plant, in which non-condensable gas remaining uncondensed in an evaporator is sent to a reduction well.

[0005] Patent Document 4 discloses a non-condensable gas reduction system used in a so-called flash geothermal power plant, in which non-condensable gas remaining uncondensed in a condenser is sent to a reduction well. Each of Patent Document 3 and Patent Document 4 discloses that the non-condensable gas reduction system includes an ejector that attracts non-condensable gas and discharges a liquid mixed with a pressurized liquid, and returns the liquid discharged by the ejector to the reduction well, thereby returning the non-condensable gas to the reduction well.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] As disclosed in Patent Documents 1 and 2, it has been proposed that non-condensable gases such as carbon dioxide or hydrogen sulfide be returned to a reinjection well along with reinjecting hot water in geothermal power generation. For example, when returning non-condensable gases to a reinjection well, there is a need to return them efficiently to the reinjection well. For example, in the non-condensable gas reduction systems disclosed in Patent Documents 3 and 4, respectively, it is disclosed that non-condensable gases are returned to a reinjection well by an ejector.

[0008] The nozzle inside the ejector has a structure that makes it prone to clogging. Therefore, impurities can adhere to the ejector and cause it to become clogged.

[0009] This disclosure provides a technology for preventing ejector clogging when reducing noncondensable gases using an ejector in a geothermal power plant. [Means for solving the problem]

[0010] This disclosure provides a non-condensable gas reduction system for a geothermal power plant, which returns non-condensable gas, which remains uncondensed when cooled in a first gas contained in geothermal fluid flowing from a production well, to a reinjection well, comprising: a pump for pressurizing a first liquid sent to the reinjection well; a first pressure gauge for measuring the pressure of the first liquid discharged from the pump; a first flow meter for measuring the flow rate of the first liquid discharged from the pump; a second pressure gauge for measuring the pressure of the non-condensable gas; a second flow meter for measuring the flow rate of the non-condensable gas; an ejector driven by the first liquid supplied from a first port, which draws the non-condensable gas from a second port and discharges a second liquid, a mixture of the first liquid and the non-condensable gas, from a third port; a third pressure gauge for measuring the pressure of the second liquid; and a control device for diagnosing blockages in the first, second, and third ports based on the measurement results of the first pressure gauge, first flow meter, second pressure gauge, second flow meter, and third pressure gauge. [Effects of the Invention]

[0011] According to this disclosure, when reducing non-condensable gases using an ejector in a geothermal power plant, measures can be taken to prevent the ejector from becoming clogged. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram of the configuration of a geothermal power plant equipped with a non-condensable gas reduction system according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram showing the configuration of the ejector in the non-condensable gas reduction system according to the first embodiment. [Figure 3] Figure 3 is a flowchart illustrating the processing of the non-condensable gas reduction system according to the first embodiment. [Figure 4] Figure 4 illustrates the cleaning process in the non-condensable gas reduction system according to the first embodiment. [Figure 5] Figure 5 illustrates the determination of the completion of the cleaning process in the non-condensable gas reduction system according to the first embodiment. [Figure 6] FIG. 6 is a diagram for explaining the end determination of the cleaning process in the non-condensable gas reduction system according to the first embodiment. [Figure 7] FIG. 7 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the first embodiment. [Figure 8] FIG. 8 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the second embodiment. [Figure 9] FIG. 9 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the third embodiment. [Figure 10] FIG. 10 is a diagram showing an outline of the configuration of an ejector included in the non-condensable gas reduction system according to the fourth embodiment. [Figure 11] FIG. 11 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the fourth embodiment. [Figure 12] FIG. 12 is a diagram showing an outline of the configuration of an ejector included in the non-condensable gas reduction system according to the fifth embodiment. [Figure 13] FIG. 13 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the fifth embodiment. [Figure 14] FIG. 14 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the sixth embodiment. [Figure 15] FIG. 15 is a diagram for explaining the cleaning process in the non-condensable gas reduction system according to the seventh embodiment. MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0014] In addition, regarding the descriptions and drawings of each embodiment, components having substantially the same or corresponding functional configurations may be denoted by the same reference numerals, thereby omitting redundant explanations. Furthermore, for ease of understanding, the scale of each part in the drawings may differ from that of the actual parts.

[0015] A non-condensable gas reduction system according to an embodiment of this disclosure will now be described. The non-condensable gas reduction system according to an embodiment of this disclosure is a system used in a geothermal power plant to return non-condensable gas, which remains uncondensed when cooled in a first gas contained in the geothermal fluid that springs from a production well, back to an injection well. The non-condensable gas reduction system according to an embodiment of this disclosure includes a pump that pressurizes a first liquid sent to an injection well, a first pressure gauge that measures the pressure of the first liquid discharged from the pump, and a first flow meter that measures the flow rate of the first liquid discharged from the pump. The non-condensable gas reduction system according to an embodiment of this disclosure also includes a second pressure gauge that measures the pressure of the non-condensable gas and a second flow meter that measures the flow rate of the non-condensable gas. Furthermore, the non-condensable gas reduction system according to an embodiment of this disclosure includes an ejector that is driven by a first liquid supplied from a first port, induces non-condensable gas from a second port, and discharges a second liquid, which is a mixture of the first liquid and the non-condensable gas, from a third port. The non-condensable gas reduction system according to an embodiment of this disclosure also includes a third pressure gauge that measures the pressure of the second liquid. Furthermore, the non-condensable gas reduction system according to the embodiment of this disclosure includes a control device that diagnoses blockages in the first port, second port, and third port based on the measurement results of the first pressure gauge, first flow meter, second pressure gauge, second flow meter, and third pressure gauge, respectively.

[0016] As an underground reduction system for non-condensable gas (NCG) in geothermal power plants, a non-condensable underground reduction system has been disclosed that, through ingenuity in the configuration and structure of above-ground equipment, induces and dissolves non-condensable gas using an ejector driven by reduced water (reduced hot water, excess cooling water, reduced pit storage water, etc.) without releasing it into the atmosphere (for example, Patent Documents 3 and 4).

[0017] The nozzles inside the ejector are prone to clogging. Over time, if the nozzles become partially blocked, the ability to draw in non-condensable gases weakens, potentially leading to poor dissolution of these gases. Furthermore, complete blockage of the ejector can reduce power generation efficiency due to insufficient extraction of non-condensable gases. Additionally, there are risks such as environmental impact from the emergency release of non-condensable gases into the atmosphere and backflow of reduced water.

[0018] This disclosure proposes a method for detecting when the nozzle of an ejector is about to become blocked, as well as countermeasures and control methods for such a situation. Specifically, the non-condensable gas reduction system according to the embodiment of this disclosure detects the blockage of the nozzle of the ejector by monitoring and detecting the pressure in the pump-ejector gas line. Furthermore, as a countermeasure when the non-condensable gas reduction system according to the embodiment of this disclosure detects the blockage of the nozzle of the ejector, the nozzle is cleaned with alkali or acid.

[0019] Furthermore, the non-condensable gas reduction system according to the disclosed embodiment can be applied in common to non-condensable gas underground reduction systems using ejectors in so-called flash-type geothermal power plants and binary-type geothermal power plants.

[0020] ≪First Embodiment≫ The non-condensable gas reduction system according to the first embodiment will be described in detail with reference to the drawings. Figure 1 is a schematic diagram of the configuration of a geothermal power plant 1 equipped with a non-condensable gas reduction system 50, which is an example of a non-condensable gas reduction system according to the first embodiment.

[0021] Geothermal power plant 1 comprises 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. Geothermal power plant 1 is a so-called flash-type geothermal power plant. Geothermal power plant 1 also comprises valves 81 and 82 and a pump 91.

[0022] [Gas-liquid separator 10] The gas-liquid separator 10 separates the geothermal fluid GF ejected from the production well PWL into steam ST and hot water HW. The geothermal fluid GF ejected from the production well PWL is either allowed to flow or blocked by the valve 81. The steam ST discharged from the gas-liquid separator 10 is sent to the power generation unit 20. The hot water HW discharged from the gas-liquid separator 10 is discharged into the reinjection well RWL. The pressure gauge 71, described later, measures the pressure of the hot water HW.

[0023] Here, steam ST is not pure water vapor, but includes gases emitted from the production well PWL, such as carbon dioxide and hydrogen sulfide.

[0024] [Power generation unit 20] The power generation unit 20 generates electricity using steam ST. The power generation unit 20 comprises 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 from the steam ST and the pressure reduced by the 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 and generates electricity. The electricity generated by the generator 22 is supplied to the outside.

[0025] [Condenser 30] The condenser 30 cools the steam ST discharged from the turbine 21 with coolant CW supplied from the cooling unit 40, more specifically, coolant CW1. The condenser 30 is a so-called surface contact condenser. The condenser 30 performs heat exchange between the coolant CW1 and the steam ST. By performing heat exchange between the coolant CW1 and the steam ST, the steam ST is cooled. As the steam ST is cooled in the condenser 30, it condenses into water. In the surface contact condenser 30, for example, the coolant CW1 cools the steam ST by flowing inside the piping of the heat exchanger, and the coolant CW1 does not come into direct contact with the steam ST.

[0026] Non-condensable gases (NCGs) such as carbon dioxide and hydrogen sulfide contained in the steam ST accumulate at the top of the condenser 30. When non-condensable gases NCG accumulate, 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 of the power generation unit 20 decreases. Therefore, it is desirable to discharge the non-condensable gases NCG accumulated in the condenser 30 from the condenser 30.

[0027] In geothermal power plant 1, the non-condensable gas (NCG) that accumulates in the condenser 30 is drawn in by the non-condensable gas reduction system 50 and discharged into the reinjection well (RWL).

[0028] [Cooling section 40] The cooling unit 40 supplies 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 the pump 91. In the condenser 30, the coolant CW2 whose temperature has risen due to heat exchange with the steam ST returns to the cooling unit 40 to be cooled.

[0029] [Non-condensable gas reduction system 50] The non-condensable gas reduction system 50 induces and discharges 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, 73, 74, and 75, flow meters 76, 77, and 78, and valves 83, 84, 85, and 86. The non-condensable gas reduction system 50 also includes a pump 55 and a strainer 56. Furthermore, the non-condensable gas reduction system 50 includes a chemical injection pump 87 and a chemical tank 88. The chemical injection pump 87 and the chemical tank 88 together are referred to as the chemical injection unit 89.

[0030] The non-condensable gas reduction system 50 is equipped with a strainer 56 upstream of the pump 55. The strainer 56 collects particles larger than the minimum diameter inside the ejector 54 and the pump 55. By providing the strainer 56, at least leaves, pebbles, sand, etc. will not flow into the ejector 54.

[0031] The ejector 54 is driven by coolant CW, more specifically coolant CWa, which is part of coolant CW1. Coolant CWa is pumped by pump 55. The ejector 54 discharges a mixture MW, which is a mixture of noncondensable gas NCG and coolant CWa.

[0032] Pressure gauge 71 measures the pressure of the hot water HW discharged from the gas-liquid separator 10. Pressure gauge 72 measures the pressure of the non-condensable gas NCG discharged from the condenser 30. Pressure gauge 73 measures the pressure of the coolant CWa discharged from the pump 55. Pressure gauge 74 measures the pressure of the chemical discharged from the chemical injection pump 87. Pressure gauge 75 measures the pressure of the mixed liquid MW discharged from the ejector 54.

[0033] Flow meter 76 measures the flow rate of non-condensable gas (NCG) discharged from the condenser 30. Flow meter 77 measures the flow rate of coolant (CWa) discharged from the pump 55. Flow meter 78 measures the flow rate of chemical discharged from the chemical injection pump 87.

[0034] Each of the flow meters 76, 77, and 78 is, for example, a differential pressure flow meter, a vortex flow meter, an ultrasonic flow meter, a wet gas meter, or a dry gas meter.

[0035] Valve 83 is located in the flow path of non-condensable gas (NCG) between the condenser 30 and the ejector 54. Valve 84 is located in the flow path of chemical between the chemical injection pump 87 and the ejector 54. Valve 85 is located in the flow path between the ejector 54 and the drain port DR. When valve 85 is opened, coolant (CWa) is drained from the ejector 54. Valve 86 is located between the ejector 54 and the reinjection well (RWL).

[0036] In the diagram, valves 83, 84, 85, and 86 that are outlined in white indicate that the valve is open. In the diagram, valves 83, 84, 85, and 86 that are outlined in black indicate that the valve is closed. Figure 1 shows the normal state of processing noncondensable gas (NCG).

[0037] The drug injection pump 87 pressurizes the drug to inject it into the piping. The drug is injected, for example, from the drive port 52a of the ejector 54.

[0038] The chemical tank 88 stores chemicals for cleaning scale. The chemicals are alkalis, such as inorganic alkalis or organic alkalis. More specifically, the chemicals are alkalis such as sodium hydroxide, potassium hydroxide, or ammonium salts. Alternatively, the chemicals may be inorganic acids or organic acids. More specifically, the chemicals may be acids such as sulfuric acid, hydrochloric acid, acetic acid, or citric acid.

[0039] (Ejector 54) The structure of the ejector 54 will now be described. Figure 2 is a schematic diagram of the configuration of the ejector 54 provided in the noncondensable gas reduction system 50, which is an example of a noncondensable gas reduction system according to the first embodiment.

[0040] The ejector 54 comprises 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 drawn in from the induction port 51a. The drive nozzle 52 is inserted into the induction section 51. Pressurized coolant CWa is supplied to the drive port 52a of the drive nozzle 52 by the pump 55. As the high-speed coolant CWa is discharged from the tip of the drive nozzle 52, a pressure drop occurs inside the ejector, the induction section 51 becomes a vacuum space, and non-condensable gas NCG is drawn in.

[0041] The ejector 54 mixes the non-condensable gas NCG and the coolant CWa and discharges the mixed liquid MW through the expanded pipe section 53.

[0042] In ejector 54, the non-condensable gas NCG and coolant CWa are mixed and discharged, and the resulting mixture MW is sent to the reinjection well RWL.

[0043] The ejector 54 is installed on the ground. Installing the ejector 54 on the ground facilitates maintenance of the ejector 54. Multiple ejectors may also be installed. Installing multiple ejectors allows maintenance to be performed without shutting down the system.

[0044] As shown in Figure 2, in the ejector 54, clogging may occur in the discharge port 53a, indicated as range A1, the induction port 51a, indicated as range A2, or the drive port 52a, indicated as range A3.

[0045] As described above, since the non-condensable gas reduction system 50 is equipped with a strainer 56, leaves, pebbles, sand, etc. do not flow into the ejector 54. For example, the cause of clogging (blockage) of the drive port 52a or discharge port 53a in the ejector 54 is thought to be silica-based scale precipitated from components of the coolant CWa, which is the driving water that drives the ejector 54. Also, the cause of clogging (blockage) of the induction port 51a is thought to be sulfur scale generated by pressure changes from hydrogen sulfide and sulfur dioxide contained in the high-temperature non-condensable gas NCG. In addition to silica-based scale and sulfur scale, the properties of geothermal hydrothermal water vary depending on the land, so the types of scale that are easily generated also differ depending on the location. Other types of scale besides silica-based scale and sulfur scale include, for example, calcium-based scale and metal ion complex scale. Furthermore, other types of scale besides silica-based scale and sulfur scale include, for example, corrosion products (oxides or sulfides) from the corrosion of pipes, etc.

[0046] (Control device 58) The control device 58 is primarily composed of a computer, including, for example, a processor, memory or other storage devices, auxiliary storage devices, 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 also be, for example, a programmable logic controller (PLC).

[0047] During power generation, if the pressure at pressure gauge 71 becomes higher than the pressure at pressure gauge 73, the control device 58 controls the valve 83 to close in order to prevent hot water HW from flowing into the condenser 30. The pressure at pressure gauge 71 is the pressure of the hot water HW, and the pressure at pressure gauge 73 is the discharge pressure of the pump 55.

[0048] The control device 58 may also monitor the pressure of the non-condensable gas NCG using the pressure gauge 72.

[0049] The control device 58 diagnoses blockages in the induction port 51a, drive port 52a, and discharge port 53a of the ejector 54 based on the measurement results of the pressure gauge 73, flow meter 77, pressure gauge 72, flow meter 76, and pressure gauge 75, respectively.

[0050] The non-condensable gas reduction system 50 detects and diagnoses blockage (occlusion) of the ejector 54. Furthermore, when the non-condensable gas reduction system 50 detects blockage (occlusion) of the ejector 54, it controls the system to resolve the blockage. Specifically, the non-condensable gas reduction system 50 detects blockage of the ejector 54 by monitoring the pressure and flow rate of the liquid or gas flowing through the piping connected to the ejector 54. Then, when the non-condensable gas reduction system 50 detects blockage in the ejector 54, it performs alkaline or acid cleaning on the ejector 54.

[0051] The non-condensable gas reduction system 50 can continuously process non-condensable gas (NCG) by eliminating clogging of the ejector 54. Furthermore, by eliminating clogging of the ejector 54, the non-condensable gas reduction system 50 can reduce maintenance costs by reducing the frequency of maintenance of the ejector 54 and preventing malfunctions.

[0052] The specific processing of the control device 58 will now be described. Figure 3 is a flowchart illustrating the processing of a non-condensable gas reduction system 50, which is an example of a non-condensable gas reduction system according to the first embodiment.

[0053] Furthermore, regarding the valve in the non-condensable gas reduction system 50, it is assumed that it is initially in the state shown in Figure 1.

[0054] (Step S1) First, the control device 58 controls the measurement of the pressure (P1) and flow rate (F1) of the driving water, the pressure (P2) and flow rate (F2) of the non-condensable gas, and the discharge pressure (P3) of the ejector.

[0055] Specifically, the control device 58 obtains the pressure (P1) of the coolant CWa, which is the driving water, from the pressure gauge 73. The control device 58 obtains the flow rate (F1) of the coolant CWa, which is the driving water, from the flow meter 77. The control device 58 also obtains the pressure (P2) of the non-condensable gas NCG from the pressure gauge 72. The control device 58 obtains the flow rate (F2) of the non-condensable gas NCG from the flow meter 76. Furthermore, the control device 58 obtains the discharge pressure (P3) of the ejector 54 from the pressure gauge 75.

[0056] (Step S2) Next, the control device 58 determines that the pressure (P1) has increased and the flow rate (F1) has decreased, the pressure of the non-condensable gas (P2) has increased from negative to positive, the flow rate of the non-condensable gas (F2) has decreased, and the discharge pressure (P3) of the ejector 54 has decreased (Condition 1). Note that the increase or decrease in pressure is performed, for example, by threshold processing by comparing it with a predetermined pressure. Similarly, the increase or decrease in flow rate is also performed, for example, by threshold processing by comparing it with a predetermined flow rate. The same applies in the following explanation.

[0057] If condition 1 is met (YES in step S2), the control device 58 determines that the drive port 52a or the discharge port 53a is becoming clogged and proceeds to step S3. If condition 1 is not met (NO in step S2), the control device 58 proceeds to step S4.

[0058] (Step S3) The control device 58 controls the non-condensable gas reduction system 50 to perform a cleaning process (cleaning of the drive port and discharge port) in order to clear blockages in the drive port 52a or the discharge port 53a. Figure 4 is a diagram illustrating the cleaning process in the non-condensable gas reduction system 50, which is an example of a non-condensable gas reduction system according to the first embodiment. The control device 58 controls the injection of chemical from the chemical injection unit 89. Specifically, the control device 58 controls the valve 83 to close in order to prevent backflow of chemical into the condenser 30. The control device 58 also controls the activation of the chemical injection pump 87 to open the valve 84.

[0059] When the chemical is injected from the induction port 51a, the chemical can remove blockages in the nozzles of the drive port 52a or discharge port 53a. Once the blockages in the nozzles of the drive port 52a or discharge port 53a are removed, a change occurs in the pressure measured in step S1. The method for determining the blockage removal (determination of the end of the cleaning process) based on the pressure change will be explained below.

[0060] Figure 5 illustrates the determination of the completion of the cleaning process in a non-condensable gas reduction system 50, which is an example of a non-condensable gas reduction system according to the first embodiment.

[0061] In Figure 5, the horizontal axis represents time T, and the vertical axis represents pressure P. As shown by line L1 in Figure 5, pressure P gradually increases from the initial pressure P0 to time T0 due to the blockage. When cleaning is started at time T0, pressure P decreases rapidly. Then, at time T1, when pressure P becomes approximately equal to the initial pressure P0, the blockage is considered to have been cleared, and the cleaning process is terminated. In other words, the control device 58 may determine that cleaning is complete.

[0062] For example, during the drive port cleaning process, the control device 58 determines whether the pressure of the coolant CWa (P1), the pressure of the non-condensable gas NCG (P2), and the discharge pressure of the ejector 54 (P3) have all recovered to their initial pressures. When the pressure of the coolant CWa (P1), the pressure of the non-condensable gas NCG (P2), and the discharge pressure of the ejector 54 (P3) have all recovered to their initial pressures, the control device 58 terminates the drive port cleaning process. The control device 58 then proceeds to step S6.

[0063] Note that the determination of the end of the process is not limited to the example in Figure 5. Another example will be described. Figure 6 is a diagram illustrating another example of the determination of the end of the cleaning process in a non-condensable gas reduction system 50, which is an example of a non-condensable gas reduction system according to the first embodiment.

[0064] In Figure 6, the horizontal axis represents time T, and the vertical axis represents pressure P. As shown by line L2 in Figure 6, pressure P gradually increases from the initial pressure P0 to time T0 due to the blockage. When cleaning is started at time T0, pressure P decreases rapidly. The cleaning process may then be terminated at time T11, when the rate of change of pressure P with respect to time T ΔP / Δt (pressure recovery rate) is approximately equal to 0, indicating that the blockage has been cleared. In other words, the control device 58 may determine that cleaning is complete.

[0065] Alternatively, the discharge port 53a may be cleaned by flowing coolant CWa from the drive port 52a to the discharge port 53a without injecting any chemical. When cleaning by flowing coolant CWa from the drive port 52a to the discharge port 53a, the output of the pump 55 may be increased, for example.

[0066] (Step S4) If condition 1 is not met (NO in step S2), the control device 58 determines that the pressure of the noncondensable gas (P2) has changed from negative to positive and that the flow rate of the noncondensable gas (F2) is 0 or decreasing (condition 2).

[0067] If condition 2 is met (YES in step S4), the control device 58 determines that the induction port 51a is becoming clogged and proceeds to step S5. If condition 2 is not met (NO in step S4), the control device 58 proceeds to step S6.

[0068] (Step S5) The control device 58 controls the non-condensable gas reduction system 50 to perform a cleaning process (cleaning of the induction port) in order to clear any blockage in the induction port 51a. Figure 7 is a diagram illustrating the cleaning process in the non-condensable gas reduction system 50, which is an example of a non-condensable gas reduction system according to the first embodiment. The control device 58 controls the system to allow the drive water (coolant CWa) to flow back into the induction port 51a. Specifically, the control device 58 controls valves 83, 84, and 86 to close. The control device 58 also controls valve 85 to open.

[0069] When valve 85 is opened, the coolant CWa flows back through the induction port 51a and is drained. When the coolant CWa flows back through the induction port 51a and is drained, the sulfur scale that had adhered to the induction port 51a is removed.

[0070] The completion of the induction port cleaning process is determined by the pressure of the non-condensable gas (P2), in the same manner as in step S3.

[0071] Furthermore, if a blockage is diagnosed in the attraction port 51a, the chemical agent may also be injected through the attraction port 51a during the attraction port cleaning process.

[0072] Then, the control device 58 proceeds to step S6.

[0073] (Step S6) The control device 58 determines whether to terminate the process. If the process is to be terminated (YES in step S6), the control device 58 terminates the process. If the process is not to be terminated, in other words, if the process is to be continued (NO in step S6), the control device 58 returns to step S1 and repeats the process.

[0074] According to the non-condensable gas reduction system of the first embodiment, measures can be taken against ejector clogging.

[0075] ≪Second Embodiment≫ The non-condensable gas reduction system according to the second embodiment will be described in detail with reference to the drawings. Figure 8 is a diagram illustrating the cleaning process in the non-condensable gas reduction system 150, which is an example of the non-condensable gas reduction system according to the second embodiment.

[0076] In the non-condensable gas reduction system 150, instead of supplying the agent to the ejector 54 as in the non-condensable gas reduction system 50, the agent is injected from the upstream side of the pump 55. In other words, in the non-condensable gas reduction system 150, the agent is injected from the suction side of the pump 55.

[0077] The non-condensable gas reduction system 150 is equipped with a control device 158 in place of the control device 58 in the non-condensable gas reduction system 50.

[0078] The control device 158 opens valve 83 during the cleaning process of the discharge port or drive port. By opening valve 83, the ejector 54 can be cleaned while simultaneously processing the non-condensable gas NCG.

[0079] ≪Third Embodiment≫ The non-condensable gas reduction system according to the third embodiment will be described in detail with reference to the drawings. Figure 9 is a diagram illustrating the cleaning process in the non-condensable gas reduction system 250, which is an example of the non-condensable gas reduction system according to the third embodiment.

[0080] In the non-condensable gas reduction system 250, instead of injecting the agent from upstream of the pump 55 as in the non-condensable gas reduction system 150, the agent is injected from downstream of the pump 55. In other words, in the non-condensable gas reduction system 250, the agent is injected from the discharge side of the pump 55.

[0081] The non-condensable gas reduction system 250 is equipped with a control device 258 in place of the control device 158 in the non-condensable gas reduction system 150.

[0082] The control device 258 opens valve 83 during the cleaning process of the discharge port or drive port. By opening valve 83, the ejector 54 can be cleaned while simultaneously processing the non-condensable gas NCG.

[0083] ≪Fourth Embodiment≫ The non-condensable gas reduction system according to the fourth embodiment will be described in detail with reference to the drawings. Figure 10 is a schematic diagram of the configuration of the ejector 354 included in the non-condensable gas reduction system 350, which is an example of the non-condensable gas reduction system according to the fourth embodiment. Figure 11 is a diagram illustrating the cleaning process in the non-condensable gas reduction system 350, which is an example of the non-condensable gas reduction system according to the fourth embodiment.

[0084] The non-condensable gas reduction system 350 is equipped with an ejector 354 in place of the ejector 54 in the non-condensable gas reduction system 50. Furthermore, the non-condensable gas reduction system 350 is equipped with a control device 358 in place of the control device 58 in the non-condensable gas reduction system 50.

[0085] The ejector 354 comprises a body 351 and a nozzle 352. The ejector 354 has an induction port 351a, a discharge port 351b, and a drug injection port 351c on the body 351. The ejector 354 has a drive port 352a on the nozzle 352.

[0086] As shown in Figures 10 and 11, the drug CS is supplied from the drug injection unit 89 to the drug injection port 351c of the ejector 354.

[0087] The control device 358 opens valve 83 during the cleaning process of the discharge port or drive port. By opening valve 83, the ejector 354 can be cleaned while simultaneously processing the non-condensable gas NCG.

[0088] ≪Fifth Embodiment≫ The non-condensable gas reduction system according to the fifth embodiment will be described in detail with reference to the drawings. Figure 12 is a schematic diagram of the configuration of the ejector 454 included in the non-condensable gas reduction system 450, which is an example of the non-condensable gas reduction system according to the fifth embodiment. Figure 13 is a diagram illustrating the cleaning process in the non-condensable gas reduction system 450, which is an example of the non-condensable gas reduction system according to the fifth embodiment.

[0089] The non-condensable gas reduction system 450 is equipped with an ejector 454 in place of the ejector 54 in the non-condensable gas reduction system 50. Furthermore, the non-condensable gas reduction system 450 is equipped with a control device 458 in place of the control device 58 in the non-condensable gas reduction system 50.

[0090] Ejector 454 is formed by connecting a first ejector 455 and a second ejector 465.

[0091] The first ejector 455 comprises a body 451 and a nozzle 452. The first ejector 455 has an induction port 451a and a discharge port 451b on the body 451. Coolant CWa discharged from the second ejector 465 is supplied to the nozzle 452 of the first ejector 455.

[0092] The second ejector 465 comprises a body 461 and a nozzle 462. The second ejector 465 has a drug injection port 461a in the body 461. Coolant CWa is supplied to the nozzle 462 of the second ejector 465.

[0093] As shown in Figure 13, the drug CS is supplied from the drug injection unit 89 to the drug injection port 461a of the second ejector 465.

[0094] The control device 458 opens valve 83 during the cleaning process of the discharge port or drive port. By opening valve 83, the cleaning process of the ejector 454 can be performed while processing the non-condensable gas NCG.

[0095] ≪Sixth Embodiment≫ The non-condensable gas reduction system according to the sixth embodiment will be described in detail with reference to the drawings. Figure 14 is a diagram illustrating the cleaning process in a non-condensable gas reduction system 550, which is an example of a non-condensable gas reduction system according to the sixth embodiment.

[0096] The non-condensable gas reduction system 550 replaces the chemical injection pump 87 in the non-condensable gas reduction system 450 with a valve 584 in place of the valve 84. The valve 584 is, for example, a control valve. Furthermore, the non-condensable gas reduction system 550 replaces the control device 458 in the non-condensable gas reduction system 450 with a control device 558.

[0097] The ejector 454 is capable of attracting the drug. Therefore, the drug can be injected by controlling the flow rate using the valve 584, without using the drug injection pump 87.

[0098] ≪Seventh Embodiment≫ The non-condensable gas reduction system according to the seventh embodiment will be described in detail with reference to the drawings. Figure 15 is a diagram illustrating the cleaning process in a non-condensable gas reduction system 650, which is an example of a non-condensable gas reduction system according to the seventh embodiment.

[0099] The non-condensable gas reduction system 650 includes an ejector 654 in addition to the ejector 54 in the non-condensable gas reduction system 50. Furthermore, the non-condensable gas reduction system 650 includes a control device 658 in place of the control device 58 in the non-condensable gas reduction system 50. In addition, the non-condensable gas reduction system 650 includes a valve 683.

[0100] The control device 658 controls the valve 683 to open and the valve 83 to close when cleaning the ejector 54. Then, the control device 658 performs the cleaning process.

[0101] The control device 658 opens valve 683 during the cleaning process of the discharge port or drive port. By opening valve 683, the ejector 54 can be cleaned while simultaneously processing the non-condensable gas NCG.

[0102] Note that the drive port 52a is an example of the first port, the induction port 51a is an example of the second port, and the discharge port 53a is an example of the third port.

[0103] The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims. [Explanation of Symbols]

[0104] 1. Geothermal power plant 30 Condenser 50, 150, 250, 350, 450, 550, 650 Non-condensable gas reduction system 51a, 351a, 451a Attraction Port 52a, 352a drive ports 53a, 351b, 451b Discharge Ports 351c, 461a Drug infusion port 54, 354, 454, 654 ejectors 55 pumps 56 Strainer 58, 158, 258, 358, 458, 558, 658 control devices 71, 72, 73, 74, 75 Pressure gauges 76, 77, 78 flowmeter 81, 82, 83, 84, 85, 86, 584, 683 valves CS medication CW, CW1, CW2, CWa Coolant DR drain GF geothermal fluid HW hot water MW mixture NCG (Non-condensable gas) PWL production well RWL Reinforcement Well ST Steam

Claims

1. In a geothermal power plant, a non-condensable gas reduction system returns the non-condensable gas that remains after cooling in the first gas contained in the geothermal fluid that springs from the production well to the reduction well. A pump for pressurizing the first liquid sent to the injection well, A first pressure gauge for measuring the pressure of the first liquid discharged from the pump, A first flow meter for measuring the flow rate of the first liquid discharged from the pump, A second pressure gauge for measuring the pressure of the noncondensable gas, A second flow meter for measuring the flow rate of the non-condensable gas, An ejector is driven by the first liquid supplied from the first port, which draws the non-condensable gas from the second port and discharges the second liquid, which is a mixture of the first liquid and the non-condensable gas, from the third port. A third pressure gauge for measuring the pressure of the second liquid, A control device that diagnoses blockages in the first port, second port, and third port based on the measurement results of the first pressure gauge, first flow meter, second pressure gauge, second flow meter, and third pressure gauge, Equipped with, Non-condensable gas reduction system.

2. It further includes a drug injection section for injecting drugs, The control device, when it diagnoses that there is a blockage in any of the first port, the second port, or the third port, controls the drug injection unit to inject the drug from the drug injection unit. The non-condensable gas reduction system according to claim 1.

3. The aforementioned agent is an alkali or an acid. The non-condensable gas reduction system according to claim 2.

4. The alkali is either an inorganic alkali or an organic alkali. The non-condensable gas reduction system according to claim 3.

5. The alkali is sodium hydroxide, potassium hydroxide, or an ammonium salt. The non-condensable gas reduction system according to claim 3.

6. The aforementioned acid is either an inorganic acid or an organic acid. The non-condensable gas reduction system according to claim 3.

7. The acid comprises at least one of sulfuric acid, hydrochloric acid, acetic acid, or citric acid. The non-condensable gas reduction system according to claim 3.

8. The aforementioned drug is injected from the suction side of the pump, the discharge side of the pump, or the first port. The non-condensable gas reduction system according to claim 2.

9. The first liquid is flowed from the first port to the second port. The non-condensable gas reduction system according to claim 1.

10. The first liquid is flowed from the first port to the third port. The non-condensable gas reduction system according to claim 1.

11. The control device determines the completion of cleaning based on the initial pressure and pressure recovery rate of each part. The non-condensable gas reduction system according to claim 1.

12. The second flow meter is one of the following: a differential pressure flow meter, a vortex flow meter, an ultrasonic flow meter, a wet gas meter, or a dry gas meter. A non-condensable gas reduction system according to any one of claims 1 to 11.

13. It also has a valve, The valve is controlled by the control device. A non-condensable gas reduction system according to any one of claims 1 to 11.

14. The scales that cause clogging include silica-based scale, calcium-based scale, metal-containing ion complex scale, and sulfur scale as corrosion products or gaseous products. A non-condensable gas reduction system according to any one of claims 1 to 11.

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