Geothermal power generation equipment

Abstract

To provide a geothermal power generator which enables stable power generation regardless of a temperature of a geothermal fluid and can resolve a problem of CO2 emission.SOLUTION: A geothermal power generator utilizes geothermal steam to rotate a turbine (103) and generate electric power and includes: a heating part (101) which heats geothermal steam; a turbine (103) which utilizes the steam heated by the heating part (101) to rotate; and a power generator (104) which is connected to the turbine (103) and generates electric power through rotation of the turbine. The turbine may be rotated by utilizing geothermal steam to generate low-boiling medium steam with a heat exchanger.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a geothermal power generation system that uses geothermal fluid to drive a steam turbine. [Background technology]

[0002] In a typical geothermal power generation system, geothermal fluid extracted from underground is separated into steam and hot water using a steam separator, and the separated steam is used to rotate a turbine to generate electricity. In the field of geothermal power generation, how to increase power generation efficiency is an important issue, and various technologies have been proposed to achieve this.

[0003] For example, Patent Document 1 employs a system in which a turbine is rotated using geothermal steam, and then a portion of the exhaust steam is pressurized using the geothermal steam to rotate another turbine through heat exchange, thereby making effective use of the exhaust steam. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-053738 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the above-mentioned background art is based on the assumption that the temperature of the geothermal fluid is high enough to operate the geothermal power generation system as is, and cannot be adopted when the temperature of the geothermal fluid is low, because a low temperature of the geothermal fluid not only reduces the efficiency of geothermal power generation, but may even make geothermal power generation impossible.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a geothermal power generation device that is capable of generating stable power regardless of the temperature of the geothermal fluid. [Means for solving the problem]

[0007] According to one aspect of the present invention, a geothermal power generation system for generating electricity using geothermal steam comprises a heating unit for heating the geothermal steam, a turbine that rotates using the steam heated by the heating unit, and a generator connected to the turbine and generating electricity by the rotation of the turbine. This enables stable power generation even when the temperature of the geothermal fluid is relatively low. According to another aspect of the present invention, the steam generating system further comprises a heat exchanger for exchanging heat between the steam heated by the heating unit and a low-boiling-point medium, and the turbine is rotated by the low-boiling-point medium vapor generated by the heat exchanger, thereby enabling power generation using a desired low-boiling-point medium. According to another aspect of the present invention, there is provided a geothermal power generation system for generating electricity using geothermal steam, comprising: a first heating section for heating the geothermal steam; a first turbine rotated by the steam heated by the first heating section; a second heating section for heating steam discharged from the first turbine; a heat exchanger for exchanging heat between the steam heated by the second heating section and a low-boiling-point medium; a second turbine rotated by the low-boiling-point medium vapor generated by the heat exchanger; a first generator connected to the first turbine; and a second generator connected to the second turbine. This improves power generation efficiency and enables stable power generation even when the temperature of the geothermal fluid is relatively low. According to another aspect of the present invention, the heating unit comprises a reactor made of a heat-resistant, corrosion-resistant, and conductive material that radiates multiple types of first electromagnetic waves with different frequencies from its wall when heated, an amplifier made of at least one alkali metal housed in the reactor that interacts with the first electromagnetic waves to increase their energy and radiate second electromagnetic waves, and a device that heats the reactor to vaporize the amplifier and radiates the first electromagnetic waves from the wall of the reactor to form a plasma space within the reactor. This allows the heating unit to heat the geothermal steam more effectively, enabling more stable power generation even when the temperature of the geothermal fluid is relatively low. In the heating unit, the reactor may be made of stainless steel or iron, and the amplification material may be at least one alkali metal plus stainless steel powder, Fe powder, or zinc powder. The heating unit may include an internal heating cylinder disposed within the reactor, to which hydrogen generated within the reactor is fed and heated by a burner. A graphite film may be attached to the inner wall of the reactor. The heating unit may include an internal heating cylinder disposed within the reactor, with multiple replaceable cassette cylinders containing amplification materials disposed between the internal heating cylinder and the inner wall of the reactor body, and a gas passage for the gas to be treated formed within these cassette cylinders. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a geothermal power generation device that is capable of generating stable power regardless of the temperature of the geothermal fluid. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing a first example of a geothermal power generation device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a second example of a geothermal power generation device according to this embodiment. [Figure 3] FIG. 3 is a schematic diagram showing a third example of a geothermal power generation device according to this embodiment. [Figure 4] FIG. 4 is a schematic diagram of the heating section of the geothermal power generation system according to this embodiment. [Figure 5] FIG. 5 is a configuration diagram showing an example of a hydrogen generating device employed in the geothermal power generation system according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the components described in the following embodiments are merely examples and are not intended to limit the technical scope of the present invention.

[0011] As illustrated in Figure 1, a geothermal power generation system according to one embodiment of the present invention has a heating section 101 that heats geothermal steam, and the high-temperature steam heated by the heating section 101 is supplied to a turbine 103. The heating section 101 has a heating device 102 that generates energy using the geothermal steam. The geothermal steam may be geothermal steam sent from a production well, or steam obtained after separating water from steam in a geothermal fluid from a production well may be used. In either case, this embodiment is capable of generating electricity even if the temperature of the geothermal steam obtained from the production well is not high enough to rotate a turbine and generate sufficient electricity.

[0012] High-temperature steam enters the turbine 103 from the heating section 101, rotating the rotor of the turbine 103, which then rotates the generator 104 connected to the rotor to generate electricity. The steam discharged from the turbine 103 is cooled in the condenser 105, and is returned to the injection well as geothermal water.

[0013] It is desirable that the heating device 102 does not use a method that burns fossil fuels, and a method that emits as little CO2 as possible should be adopted. The heating unit 101 uses geothermal steam to heat the geothermal steam, thereby increasing the pressure to a level that rotates the turbine 103. For example, a burner may be provided in the heating unit 101, and gas obtained from the geothermal steam may be burned to increase the pressure of the geothermal steam.

[0014] One embodiment of the present invention can also be applied to the geothermal power generation system shown in Fig. 2 or 3. Note that blocks having the same functions as those in Fig. 1 are given the same reference numerals and will not be described again.

[0015] The geothermal power generation system illustrated in Fig. 2 has a configuration in which a low-boiling-point medium is circulated through a heat exchanger 201, a turbine 202, and a condenser 203 in addition to the heating unit 101 described above. Steam pressurized by the heating unit 101 enters the heat exchanger 201, where the low-boiling-point medium becomes steam, rotating the turbine 202 and generating electricity through a generator 204 connected to the turbine 202. The steam discharged from the turbine 202 is liquefied by the condenser 203 and returned to the heat exchanger 201, and the circulation process continues in the same manner. Furthermore, the geothermal steam that has passed through the heat exchanger 201 is returned to the reinjection well through the condenser 105, as described above.

[0016] The geothermal power generation system shown in Figure 3 has two heating sections 101 and 101a, and has a configuration in which the systems in Figures 1 and 2 are connected. First, geothermal steam is heated by the first heating section 101, and the high-temperature steam enters the turbine 103, rotating the generator 104 connected to the turbine 103 to generate electricity. The steam discharged from the turbine 103 enters the second heating section 101a and is heated by the heating device 102a of the second heating section 101a.

[0017] The steam heated by the second heating unit 101a enters the heat exchanger 201, where the low boiling point medium turns into steam, which rotates the turbine 202, and electricity is generated by the generator 204 connected to the turbine 202. The steam discharged from the turbine 202 is liquefied by the condenser 203 and returns to the heat exchanger 201, and is circulated in the same manner thereafter.

[0018] In this way, the geothermal steam is heated to rotate the turbine 103, and the exhaust steam is further heated and exchanged with the turbine 202 to rotate the turbine 202, thereby enabling efficient power generation.

[0019] The heating units 101 and 101a heat low-temperature steam, but as a method for doing so, it is also possible to directly use high-temperature steam to heat geothermal steam, as shown in the example of FIG.

[0020] 4, the heating section 101 or 101a is composed of a heating device 301 and an ejector 302. The high-temperature steam generated by the heating device 301 is supplied to the ejector 302, where it is combined with geothermal steam to output the desired high-temperature steam.

[0021] As mentioned above, the heating devices 102, 102a, and 301 preferably use a heating method that minimizes CO2 emissions. Various methods, such as those using hydrogen, can be employed. For example, a method (Patent No. 5911980) can be used in which sodium hydroxide or potassium hydroxide is stored as a reactant in a fine particle generator, and fine particles are generated while the reactant is heated and metal elements are supplied from a metal element supplier. These fine particles are then sent to a heated reactor separate from the generator, and water is supplied to the reactor, after which hydrogen is generated (see, for example, Japanese Patent Publication No. 2017-222550). Other methods that may be used include generating hydrogen using sodium hydride (NaH) (see, for example, Japanese Patent Publication No. 2018-080071), generating a sodium carbonate aqueous solution from exhaust gas from a combustion device and a caustic soda aqueous solution, supplying the resulting solution to a heated reactor, and then contacting the resulting solution with a stainless steel catalyst in a stainless steel container to generate hydrogen (see, for example, Japanese Patent Publication No. 2018-080071). The following describes the preferred method disclosed in Japanese Patent Publication No. 2020-163377. However, these methods are merely examples, and the present invention is not limited to these, and other methods may also be used.

[0022] In FIG. 5, the heating device 102 preferably has a stainless steel reactor 401, the inner wall of which is coated with a graphite film 402 to prevent oxidation of the stainless steel and to enhance electromagnetic wave radiation (cavity radiation). A heater 403 is provided around the outer periphery of the lower half of the reactor 401, allowing the interior of the reactor 401 to be heated to approximately 400 to 700°C. A supply pipe 404 for introducing gas obtained from geothermal steam is provided on the upper surface of the reactor 401, and this supply pipe 404 is positioned so as to open into a plasma space 405 formed in the upper half of the reactor 401. An exhaust pipe 406 for discharging gas generated by reaction in the plasma space 405 is provided on the upper surface of the reactor 401. A radiation auxiliary body 407 consisting of multiple radiation plates 407a, 407b, etc. is placed on the bottom of the reactor 401 to increase the electromagnetic wave radiation area, and an electromagnetic wave amplification material 408 is housed together with this radiation auxiliary body 407. The auxiliary radiation body 407 may be made of the same material as the reactor 401 or may be powder of the same material, for example, iron or stainless steel powder of about 70 μm.

[0023] The electromagnetic wave amplifying material 408 is at least one of an alkali metal element (lithium (Li), sodium (Na), or potassium (K)), or alternatively, a fluoride of an alkali metal element (LiF, NaF, KF). Adding stainless steel powder, iron powder, or zinc powder to these alkali metals in a 1:1 ratio improves the reaction efficiency. The electromagnetic wave amplifying material 408 has a single outermost electron and is a highly chemically active metal, and the inner electron easily jumps to the outer orbit when heated. Furthermore, these metal elements and their fluorides have relatively low melting points (Li: 180°C, Na: 98°C, K: 64°C, LiF: 460°C), and when heated, they melt easily and become liquid. For example, when heated to 400°C or higher, the energy amplification effect of the amplifying material causes the temperature to rise, and the thermal vibration of the molecules causes them to fly out as fine particles, filling the plasma space 405.

[0024] Nitrogen gas, carbon dioxide gas, etc. separated from the air are introduced into the supply pipe 404 of such a reactor 401, and by heating it to a predetermined temperature with a heater 403, the reactor becomes filled with fine particles of electromagnetic wave amplifying material 408, which act as a laser medium to amplify the electromagnetic waves from the vessel wall, thereby converting part of the nitrogen gas, carbon dioxide gas, etc. inside the reactor into hydrogen and discharging it from an exhaust pipe 406. Only hydrogen can be collected from the gas discharged from the exhaust pipe 406, for example, by a hydrogen-nitrogen separator 409.

[0025] The geothermal power generation system according to this embodiment can be applied to production wells where the geothermal fluid is relatively low in temperature, but can also be applied to production wells where the temperature of the geothermal fluid changes. That is, the temperature of the geothermal fluid is detected, and if the temperature drops, the heating device 102 is operated to increase the pressure. This enables stable geothermal power generation. [Industrial Applicability]

[0026] The present invention is particularly applicable to geothermal power plants where the geothermal fluid is relatively cold. [Explanation of symbols]

[0027] 101, 101a Heating section 102, 102a, 301 heating device 103 Turbine 104 Generator 105 Condenser 201 Heat exchanger 202 Turbine 203 Condenser 204 Generator

Claims

1. A geothermal power generation device that generates electricity using geothermal steam, a heating unit that heats the geothermal steam; a turbine that rotates using steam heated by the heating unit; a generator connected to the turbine and generating electricity by rotation of the turbine; It consists of A geothermal power generation device characterized in that the heating method of the heating unit utilizes hydrogen generated in a reactor provided in the heating unit.

2. The apparatus further includes a heat exchanger that performs heat exchange between the vapor heated by the heating unit and a low-boiling-point medium, 2. The geothermal power generation system according to claim 1, wherein the turbine is rotated by the low boiling point medium vapor generated in the heat exchanger.

3. A geothermal power generation device that generates electricity using geothermal steam, a first heating section that heats the geothermal steam; a first turbine that is rotated by steam heated by the first heating section; a second heating section that heats exhaust steam from the first turbine; a heat exchanger that performs heat exchange between the vapor heated by the second heating unit and a low-boiling-point medium; a second turbine rotated by the low boiling point medium vapor generated in the heat exchanger; a first generator coupled to the first turbine; a second generator coupled to the second turbine; It consists of A geothermal power generation device characterized in that the heating method of the first heating unit and the second heating unit utilizes hydrogen generated in reactors provided in the first heating unit and the second heating unit.

4. The reactor radiates a plurality of types of first electromagnetic waves with different frequencies from the wall surface of the reactor when heated, and an amplifying material is stored in the reactor that interacts with the first electromagnetic waves to increase the energy of the first electromagnetic waves and radiate second electromagnetic waves, and when the reactor is heated, the amplifying material is vaporized and the first electromagnetic waves are radiated from the wall surface of the reactor, forming a plasma space in the reactor, The gas generated by the reaction in the plasma space is discharged from an exhaust pipe provided in the reactor, The hydrogen is collected from the gas discharged from the discharge pipe.

4. The geothermal power generation device according to claim 1, wherein the first and second electrodes are connected to the first and second electrodes.

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