JP2019143517A - Geothermal exchange system and geothermal power generation system - Google Patents

Abstract

To provide a geothermal exchange system capable of efficiently exchanging heat even using a middle/low temperature geothermal region having a temperature of about 180°C or less.SOLUTION: The geothermal exchange system comprises: a geothermal heat exchanger 5 disposed in such a manner that a lower region of a pipe 3 provided in the ground comes into contact with a geothermal region 4; a pressure regulating device 8 monitoring and controlling pressure inside the geothermal heat exchanger 5; and a pressure regulating valve 7 connected to the pressure regulating device 8. In an operation preparation stage, the inside of the geothermal heat exchanger 5 is pressurized to a saturated pressure of a working fluid determined by a temperature of the geothermal region 4, the working fluid is injected into the geothermal heat exchanger 5, the working fluid of high temperature and high pressure is produced without boiling the working fluid, and stored in a fixed amount, and then the inside of the geothermal heat exchanger 5 is decompressed to a steam pressure necessary for a turbine to produce steam.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a geothermal exchange system and a geothermal power generation system that can efficiently extract geothermal energy.

  Geothermal power generation using geothermal energy uses a high-temperature magma layer as a heat source and can be made into semi-permanent thermal energy and does not generate greenhouse gases in the process of power generation. In recent years, it has attracted attention as a fuel alternative. In addition, due to the accident at the nuclear power plant, Japan's energy policy, which relied heavily on nuclear power, has been reevaluated from the ground up, and expectations for the use of geothermal energy are increasing.

  Conventional geothermal power generation generates electricity by boring the geotropics and using natural pressure to extract natural steam and hot water that exist in the geotropics. Therefore, the extracted steam and hot water contain a large amount of sulfur and other impurities peculiar to the earth and tropics. This impurity becomes a scale and adheres to a heat well, piping, a turbine, or the like. If the scale adheres, the power generation output decreases over time, making long-term use difficult.

  In order to solve the problem due to the scale, Patent Literature 1 and Patent Literature 2 describe a geothermal exchanger that employs a method of sending water from the ground and collecting energy. Moreover, regarding geothermal energy recovery, Patent Document 3 discloses a geothermal exchanger that employs a method of repairing a delay in heat conduction in the geotropics.

Japanese Patent No. 4927136 Japanese Patent No. 6176890 Japanese Patent No. 5839528

  In Patent Document 1, the single-phase flow of high-pressure hot water taken out by a geothermal exchanger installed underground is taken out as steam by a steam separator, but the working water circulating in the double pipe Since the head loss is increased, the overall efficiency of the pressurizing pump is increased due to the increased capacity. Also, in the process of boring work for installing a double pipe, it is difficult to construct a double pipe in a straight line in the case of a hard rock layer at a high depth, which causes an increase in the cost of boring work. There is a problem of becoming.

  Moreover, although what was described in patent document 2 is made to boil under reduced pressure in the geothermal exchanger installed in the underground, and takes out a gas-liquid two-phase flow on the ground, also in this case, a double pipe is used. In the process of boring work for installing, it is difficult to construct a double pipe in the case of a hard rock layer at a high depth, which causes an increase in the cost of boring work.

  Furthermore, what is described in Patent Document 3 is to apply a heater to the bottom of a geothermal exchanger installed in the basement to compensate for a temperature drop due to a time delay during heat conduction from the geotropics. This power source uses a part of the power generation output, so that there is a drawback that the overall power generation efficiency is lowered.

  Thus, when it is difficult to construct a double pipe in a straight line, it is necessary to perform oblique digging or non-linear boring. In addition, the main geothermal areas in Japan are often hot spring areas, and in order to obtain the consent of the areas concerned about hot spring depletion, in addition to not taking out geothermal fluid, it can also be applied to hot spring production It is important to develop a highly efficient geothermal exchange system. In geothermal development, the temperature of the geotropy often changes due to the shallow depth of the geotropy in the medium and low temperature zone of about 180 ° C. or less, which is overwhelmingly present throughout the country. Development of a small-capacity geothermal power generation system that can cope with such time delays in geothermal conduction is important.

  The present invention has been made in consideration of such circumstances, and provides a geothermal exchange system capable of efficiently exchanging heat even when using a medium and low temperature geotropy of about 180 ° C. or less. The purpose of this project is to provide a geothermal power generation system that can generate electricity well, increase the number of geothermal development sites, and increase the amount of geothermal energy collected.

  In order to solve the above-mentioned problems, a geothermal heat exchange system according to the present invention includes a geothermal exchanger formed so that a lower region of a pipe provided in the ground is in contact with the geotropics, and a geothermal exchanger. It is equipped with a pressure regulator that monitors and controls the internal pressure, and a pressure regulator that is connected to the pressure regulator and installed at the top of the geothermal exchanger. The inside of the geothermal exchanger is pressurized until the working fluid saturation pressure determined by the tropical temperature is reached, the working fluid is injected into the geothermal exchanger, and the working fluid does not boil in the geothermal exchanger. After the working fluid is generated and stored in a certain amount, a part of the high-temperature and high-pressure working fluid is reduced by reducing the pressure inside the heat exchanger installed on the ground or the steam pressure required by the turbine. Boil and produce steam Characterized in that it.

  In the operation preparation stage, the working fluid injected into the geothermal exchanger is vaporized by pressurizing the geothermal exchanger until the pressure in the geothermal exchanger reaches the saturation pressure of the working fluid determined by the temperature of the geotropics. In addition, a certain amount can be stored in the bottom of the geothermal exchanger in the state of pressure fluid, and a large heat capacity can be provided. Therefore, geothermal heat can be recovered stably even in the middle and low temperature geotropics of about 180 ° C. or less where the temperature change is large. On the other hand, if such pressurization is not performed in the operation preparation stage, the working fluid injected into the geothermal exchanger is immediately vaporized, and a certain amount is placed at the bottom of the geothermal exchanger in the state of the pressure fluid. It cannot be stored, and geothermal heat cannot be stably recovered as a medium to low temperature geotrophic target of about 180 ° C. or lower.

  In the geothermal exchange system of the present invention, pressurization in the geothermal exchanger in the operation preparation stage is performed by press-fitting compressed air into the geothermal exchanger via a pressure regulating valve. Can do.

  During operation, in the deepest part of the geothermal exchanger, when the working fluid is water, from the total value of the saturation pressure of the pressure water that is supplied with heat from the geotropics, the pressure of the pressure water and the loss head of the circulating water, Pressurize by subtracting the water pressure proportional to the depth of the well. In this case, in the mid-low-temperature tropics, it is advantageous that the saturation pressure determined by the temperature of the tropics is low, so that the capacity of the pressure pump can be reduced and the efficiency of the system can be increased.

  In the geothermal exchange system of the present invention, the extracted steam is liquefied after being introduced into a heat exchanger installed on the ground or a turbine and exchanging heat, and descends in the pipe to be stored at the bottom of the geothermal exchanger. The amount of steam produced by circulating the working fluid and setting and controlling the pressure of the geothermal exchanger to the steam pressure required by the heat exchanger or turbine Can be controlled.

  Since the pressure water stored at the bottom of the geothermal exchanger can be stored with sufficient heat capacity stored at the bottom of the geothermal exchanger, it can have a heat capacity that can respond to changes in well temperature over time. Geothermal energy can be recovered, and when applied to power generation, power generation output can be stabilized.

  In the geothermal exchange system of the present invention, when the inner pipe for lowering the working fluid into the geothermal exchanger is inserted into the outer pipe constituting the geothermal exchanger, the inner pipe is inserted into the outer pipe. In this cross section, the inner tube can be configured to be non-concentric with the outer tube.

  Since the inner tube is non-concentric with the outer tube, the inner tube can be easily inserted into the outer tube formed in advance to constitute a geothermal exchanger.

  In the geothermal exchange system of the present invention, the geothermal exchanger includes a lower region that functions as a heat collection / storage zone to which heat is supplied from the geotropics, and heat for moving the heat obtained in the lower region upward. It is comprised by the intermediate area | region used as a movement zone, and the upper area | region connected to the heat exchanger installed on the ground, The said intermediate | middle area | region can be set as the structure formed with the flexible pipe | tube.

  By using a flexible tube, even in the case of oblique boring, the geothermal exchanger can be easily formed in the ground, so the difficulty of boring can be reduced, The difficulty of inserting into a well is reduced, which can contribute to well recycling.

  In the geothermal exchange system of the present invention, the working fluid can be injected into the geothermal exchanger by press-fitting the working fluid into the geothermal exchanger with a pressurizing pump.

  In the geothermal exchange system of the present invention, the output sides of a plurality of geothermal exchangers are connected in parallel, and the steam obtained by using the respective geothermal exchangers can be collected in total.

  By collecting the total steam obtained by the geothermal exchanger, the capacity of the turbine, condenser, generator, transformer, etc. can be designed to be large.

  The geothermal power generation system of the present invention is characterized in that power generation is performed using the geothermal exchange system of the present invention.

  Steam can be produced using mid-low temperature geotropics, which are overwhelmingly distributed throughout the country, so the number of geotropics to be used increases and a large number of geothermal power generation can be realized.

  According to the present invention, it is possible to stably produce steam by using mid-low temperature geotropics of about 180 ° C or less, which are overwhelmingly distributed nationwide, and therefore increase the number of geotropics to be used. Is possible. Therefore, geothermal power generation can be realized at many points. Furthermore, it is possible to regenerate power wells that are not in operation, and to regenerate hot springs that use hot spring wells, and can also be applied to wells such as oblique boring.

It is a figure which shows the structure of the geothermal exchange system which concerns on embodiment of this invention. It is AA sectional drawing in FIG. It is a figure which shows the shape of the geothermal exchanger at the time of carrying out diagonal boring. It is a figure which shows the structure of the geothermal power generation system which concerns on embodiment of this invention. It is a figure explaining the example of reduction of the head of a pressurization pump.

Below, the geothermal exchange system and geothermal power generation system of this invention are demonstrated based on the embodiment.
In FIG. 1, the structure of the geothermal exchange system which concerns on embodiment of this invention is shown.
The geothermal exchange system 1 includes a geothermal exchanger 5 that is formed so that a lower region of a pipe 3 installed in a casing 2 provided in the ground is in contact with the geotrophic region 4. A temperature / pressure / flow meter 6 is connected to the geothermal exchanger 5 on the ground, and a pressure adjusting device 8 is connected via a pressure adjusting valve 7. The pressure adjusting device 8 has a function of monitoring and controlling the pressure inside the geothermal exchanger 5. In addition, a heat exchanger 10 is connected to the geothermal exchanger 5 via a steam valve 9. A pressure pump 11 is connected to the heat exchanger 10, and a working fluid supply tank 12 is connected to the pressure pump 11.

  In the operation preparation stage, the inside of the geothermal exchanger 5 is pressurized until the pressure inside the geothermal exchanger 5 becomes the saturated pressure of the working fluid determined by the temperature of the geotrophic zone 4. The pressurization in the geothermal exchanger 5 at the operation preparation stage can be performed by press-fitting compressed air into the geothermal exchanger 5 via the pressure regulating valve 7. Specifically, using the temperature / pressure / flow meter 6, the compressed air from the pressure regulating valve 7 is pressed into the geothermal exchanger 5 until the saturated pressure of the working fluid determined by the temperature of the geotrophic 4 is reached. .

  Thus, the working fluid is injected into the geothermal exchanger 5 from the working fluid supply tank 12 by pressurizing the inside of the geothermal exchanger 5 to be in a high pressure state. At this time, the working fluid can be pressed into the geothermal exchanger 5 from the working fluid supply tank 12 using the pressurizing pump 11. Further, the pressurization in the geothermal exchanger 5 in the operation preparation stage is performed by closing the pressure regulating valve 7 and the steam valve 9 to seal the geothermal exchanger 5 and operating from the working fluid supply tank 12 into the geothermal exchanger 5. It can also be achieved by injecting fluid.

  Since the pressure in the heat exchanger 5 is the saturation pressure of the working fluid determined by the temperature of the geotropy 4, the working fluid is not boiled in the geothermal exchanger 5, and a high-temperature and high-pressure working fluid is generated. Then, a certain amount is retained in the lower region of the geothermal exchanger 5.

  At the next operation start stage, the pressure regulating valve 7 is closed and the steam valve 9 is gradually opened, whereby the pressure in the geothermal exchanger 5 is gradually reduced. The pressure in the geothermal exchanger 5 is reduced until the steam pressure required by the heat exchanger 10 is reached, and the working fluid heated by the geotropy 4 rises as steam and is introduced into the heat exchanger 10. The The steam exchanged by the heat exchanger 10 is liquefied by the cooling water, injected into the geothermal exchanger 5 by the pressurizing pump 11, descends, is superheated at the deepest part of the pipe 3, and is again operated at high temperature and high pressure. A fluid is generated. In this cycle, the heat capacity of the geothermal heat supplied is balanced by the amount of steam at which the amount of heat on the load side on the consumption side is the same. By repeating this, geothermal energy can be taken out continuously.

  The working fluid circulated to the deepest part of the geothermal exchanger 5 during operation is determined from the sum of the saturation pressure of the pressure water supplied with heat from the geotrophic zone 4, the pressure of the pressure water, and the head loss of the circulating water. Pressurize by subtracting the water pressure proportional to the depth. In this case, the low saturation pressure determined by the temperature of the geotropy 4 works effectively in the middle and low temperature tropics, and the efficiency of the system can be increased by reducing the capacity of the pressurizing pump 11 in the present invention. .

  During the above-described operation, the pressure in the geothermal exchanger 5 is constantly monitored by the pressure adjusting device 8 to the steam pressure required by the heat exchanger 10 that is a load, and the working fluid is contained in the geothermal exchange system 1. By controlling the pressure, which is proportional to the saturation temperature of the working fluid, by monitoring the temperature, pressure and flow rate of the steam, and controlling the opening of the steam valve 9 at the required timing, It is possible to construct a system that stably controls the amount of steam that can be produced and compensates for the time delay of heat conduction from the geotropics 4.

  As described above, when the pressure is gradually reduced by the pressure regulating valve 7 at the start of operation, the inside of the geothermal exchanger 5 is also reduced, so that the pressurized high-temperature working fluid is vaporized and rises as steam, The heat exchanger 10 is introduced. The heat-exchanged steam is liquefied and then press-fitted by the pressurizing pump 11 and heated again by the earth and tropics 4 to continuously produce steam.

  By using highly treated pure water as the working fluid, the inside of the geothermal exchange system 1 can be operated for a long time without any scale adhering. The working fluid is basically made of water or an optimal material other than water that matches the temperature of the geothermal zone that supplies heat and the temperature of the steam to be extracted.

  An emergency release valve 13 is attached to the top of the geothermal exchanger 5. In this system, the pressure in the geothermal exchanger 5 may rise suddenly due to a sudden change in load, a sudden change in well temperature, etc., but when such a situation occurs, the emergency release valve 13 The pressure in the geothermal exchanger 5 can be adjusted.

  When the heat exchanger 10 is replaced with a turbine, it can function as a power generation system. Furthermore, if heat is exchanged with the working fluid of the binary power generation system in the heat exchanger 10, it can function as binary power generation.

  The inner pipe 14 for lowering the working fluid may be inserted into the pipe 3 functioning as the outer pipe 15 constituting the geothermal exchanger 5, and the inner pipe 14 is the outer pipe. As shown in FIG. 2, the inner tube 14 may be non-concentric with the outer tube 15 in a cross section when inserted into the tube 15. If it is non-concentric, when the inner pipe 14 is installed later on the existing pipe 3, the degree of freedom of installation is increased and the installation can be performed easily. Depending on the situation, the inner tube 14 and the outer tube 15 may have a concentric structure in a cross section when the inner tube 14 is inserted into the outer tube 15, and may be a single tube instead of being a double tube. It is good also as a structure. In FIG. 2, the casing 2 is omitted.

  The geothermal exchanger 5 includes a lower region 16 that functions as a heat collection / storage zone to which heat is supplied from the geotrophic region 4, and an intermediate region that serves as a heat transfer zone for the heat obtained in the lower region 16 to move upward. 17 and an upper region 18 connected to the heat exchanger 10 installed on the ground, and the intermediate region 17 is formed by a flexible tube. A cementing 19 is applied to the upper region 18.

FIG. 3 shows the shape of the geothermal exchanger when oblique boring is performed.
In FIG. 3, the intermediate region 17 of the geothermal exchanger 5 is formed by a flexible tube. In the case of diagonal boring, the straight pipe-type geothermal exchanger 5 cannot be inserted into the ground, but by using a flexible pipe, the geothermal exchanger 5 can be easily inserted into the ground even in the case of diagonal boring. Can be formed. In this way, the difficulty of boring can be reduced, and in particular, the difficulty of inserting into existing thermal wells can be reduced, contributing to well recycling. Moreover, the fracture | rupture risk at the time of disasters, such as an earthquake of the geothermal exchanger 5, can be reduced.

  By closing the lower part of the casing 2 installed at the time of boring, it can be set as the outer pipe | tube 15 of the geothermal exchanger 5, Thereby, a casing can be used as the geothermal exchanger 5 as it is. This greatly contributes to the reduction of construction costs.

  It can be set as the structure by which the output side of the some geothermal exchanger 5 is connected in parallel, and the steam obtained using each geothermal exchanger 5 is collected in total.

  By collecting the steam obtained by the geothermal exchanger 5 in total, the capacity of the turbine, condenser, generator, transformer, etc. can be designed to be large. Also, efficient energy collection is possible by averaging output changes caused by individual temperature changes of a plurality of geothermal wells.

  In the geothermal system 1 of the present invention, the capacity of the pressurizing pump 11 can be designed very small. In principle, the working fluid that circulates in the geothermal exchange system 1 only needs to circulate as much as the load required by the turbine 20 or the heat exchanger 10, and the loss head can be designed small.

  The pump capacity represented by P = 9.8QH / η (H = total pump head, Q = circulated water volume, η = efficiency) is proportional to the circulating amount of working fluid, and most of the pump head is Therefore, the pump capacity of the system can be drastically reduced, and the efficiency of the system can be designed high.

  As described above, the geothermal exchange system 1 creates and stores a high-temperature pressurized working fluid corresponding to the temperature of the geothermal supply source in the geothermal exchanger 5 that reaches the high-temperature part of the geotrophic region 4, and stores the high-temperature pressurized A part of the working fluid is boiled and taken out as a steam by the difference between the high-temperature and high-pressure working fluid and the steam pressure required by the heat exchanger 5 or the turbine 20, and is vaporized into steam. The fluid is liquefied by heat exchange and returned to the storage tank by the pressurizing pump 11 and circulated.

  On the other hand, the amount of heat corresponding to the amount vaporized from the hot-pressurized working fluid stored and taken out as steam is replenished from the geothermal supply source, so that the thermal balance of the entire system is balanced. Since the temperature change of the well is large in the medium and low temperature geothermal zone of about 180 ° C or less, the heat balance of the entire system is higher at the high temperature and pressure working fluid, and the higher the storage volume, the more stable the heat balance. It is a system that produces a certain amount of high-temperature stored fluid before the start of operation.

  Furthermore, the mechanism of heat transfer in the stored fluid in the deepest part of the geothermal exchanger 5 is to supply heat by the “convection” of the working fluid in the stored fluid from the heat loss due to vaporization in the upper part of the geothermal exchanger 5. Therefore, it is desirable that the high-temperature pressurized working fluid stirs greatly in the lower part of the geothermal exchanger 5 that is a storage tank. Therefore, the position where the working fluid is returned to the storage tank by the pressurizing pump 11 is the deepest part of the well. It is also important to eliminate the time difference in heat supply by making the lower region 16 of the outer tube 15 that receives heat supply from the geothermal supply source, a material having excellent heat conduction.

  Moreover, in the deepest part of the geothermal exchanger 5, the water pressure proportional to the depth of the well is obtained from the sum of the saturation pressure of the pressure water that receives heat supply from the geotrophic zone 4, the pressure water pressure, and the loss head of the circulating water. In many cases, the efficiency of the entire system can be increased by reducing the capacity of the pressure pump 11. Moreover, the system which guaranteed the time delay of geothermal conduction can be constructed | assembled by enlarging the quantity of the pressure water stored at the bottom part of the geothermal exchanger 5. FIG.

In FIG. 4, the structure of the geothermal power generation system which concerns on embodiment of this invention is shown.
The configuration of the geothermal exchanger 5 is the same as that shown in FIG. 1, and in the operation preparation stage, the geothermal exchange is performed until the pressure in the geothermal exchanger 5 becomes the saturated pressure of the working fluid determined by the temperature of the geotrophic zone 4. The inside of the vessel 5 is pressurized. The pressurization in the geothermal exchanger 5 at the operation preparation stage can be performed by press-fitting compressed air into the geothermal exchanger 5 via the pressure regulating valve 7. Further, the pressurization in the geothermal exchanger 5 in the operation preparation stage is performed by closing the pressure regulating valve 7 and the steam valve 9 and sealing the geothermal exchanger, and from the working fluid supply tank 12 in the next step to the geothermal exchanger. This can be implemented by injecting a working fluid into 5.

  Thus, the working fluid is injected into the geothermal exchanger 5 from the working fluid supply tank 12 by pressurizing the inside of the geothermal exchanger 5 to be in a high pressure state. At this time, the working fluid can be pressed into the geothermal exchanger 5 from the working fluid supply tank 12 using the pressurizing pump 11.

  Since the pressure in the heat exchanger 5 is the saturation pressure of the working fluid determined by the temperature of the geotropy 4, the working fluid is not boiled in the geothermal exchanger 5, and a high-temperature and high-pressure working fluid is generated. Then, it stays in the lower region of the geothermal exchanger 5.

  At the next operation start stage, the pressure regulating valve 7 is closed and the steam valve 9 is gradually opened, whereby the pressure in the geothermal exchanger 5 is gradually reduced. The pressure in the geothermal exchanger 5 is reduced until the steam pressure required by the turbine 20 is reached, and the working fluid heated by the geotropy 4 rises as steam and is introduced into the turbine 20.

  Thus, steam is continuously produced by balancing the heat supply and the pressure of the turbine 20 with the pressure of the high-temperature and high-pressure working fluid and the steam pressure required by the turbine 20. After moving the turbine 20, the steam is introduced into the condenser 21, liquefied by the condenser 21, then pressed into the geothermal exchanger 5 by the pressurizing pump 11, heated again by the geotrophic 4, and continuously Steam is produced.

  Table 1 shows a steam table when the working fluid is water.

  As shown in this steam table, when the pressure in the geothermal exchanger 5 is atmospheric pressure (0.101 MPa), steam at 100 ° C. and 130 ° C. when the pressure is 0.270 MPa can be taken out. When the working fluid has a lighter mass than water, heat energy can be taken out as steam to a lower temperature range. In this case, it can be used for binary power generation, hot spring production, and the like.

  The pressure inside the geothermal exchanger 5 is constantly monitored and controlled by a pressure regulating device 8 connected to the pressure regulating valve 7 in accordance with the steam pressure required by the turbine 20. 4 is supplied with heat and becomes high-temperature pressure water (for example, a temperature of about 180 ° C. and a pressure of 1.002 MPa). In a region lower than the pressure water pressure, the working water is vaporized into steam. Therefore, a temperature lower than the high-temperature pressure water (for example, a saturation pressure of 0.27 Mpa corresponding to a temperature of 130 ° C.) is set as the pressure of the turbine 20.

  When the temperature of the steam capable of driving the turbine is 130 ° C., the boiling pressure is 0.27 Mpa. When hot water (1.002 Mpa) at 180 ° C. is obtained at the bottom of the well, which is a heat source, if the pressure in the tube 3 is set to 0.27 Mpa, the enclosed water (working fluid) is It vaporizes instantly and becomes steam. The working fluid that has been vaporized into vapor rapidly rises in the pipe 3, is cooled by the heat exchanger 10 provided in the upper part, returns to water, is lowered in the pipe 3, and is heated again. It becomes steam.

  Table 2 shows a comparison between the present invention and Japanese Patent No. 4927136, Japanese Patent No. 6176890, and Japanese Patent No. 5839528.

Based on FIG. 5 and Table 3, an example of reducing the head of the pressurizing pump will be described.
Table 3 shows data on hot spring wells in Kuju district, Kuju-cho, Oita, owned by the joint applicant of this application.

The pressures at the points (1) to (5) shown in FIG. 5 are as follows.
(1) Pressure required by the pressure pump (2) Water pressure proportional to the depth of the well at the circulating water pressure inlet (3) Saturation pressure of the pressure water (4) Water pressure due to the water level of the pressure water at the pressure water pressure inlet ( 5) Head loss of circulating water

The pressure P required by the pressure pump is
(1) = (3) + (4) + (5) − (2) (unit: MPa)
Capacity of pressure pump (kW)
= 9.8 × circulated water volume (t / s) × pump head (m) × 100 ÷ efficiency, so most of the required head of the pump that is press-fitted into the 180 ° C pressure water zone can be covered with water pressure .

In cases where the well depth is deep and the well temperature is low as shown in Table 4, the pressurization pump can be dispensed with when the following calculation is satisfied.
0> (3) + (4) + (5)-(2) = − 6.1595

  The calculation conditions here ignore the loss head of circulating water, and the height from the deepest part of the pressure water is 200 m. In general wells, the water pressure obtained at a depth where pressure water can be obtained is a numerical value that is an order of magnitude greater than the saturated vapor pressure, and therefore a pressurizing pump is often unnecessary.

A comparison between the “heat pipe” technology already in practical use and the present invention will be described below.
What is put into practical use as a heat pipe system is a method in which the working fluid is sealed after reducing the boiling point of the working fluid after reducing the boiling point of the working fluid. Take out as. After the heat exchange, the working fluid returns to the liquid and circulates in the pipe. Since heat is exchanged between the working fluid of the descending working fluid and the rising liquid, the efficiency is deteriorated.

  On the other hand, the present invention generates a high-temperature working fluid by pressurizing the working fluid with a pressurizing pump or sealing the inside of the geothermal exchanger after pressurizing the inside of the pipe in the operation preparation stage. Yes, this point is very different from the heat pipe method. When a high-pressure / high-temperature working fluid stays at the bottom of the pipe and a load is applied by opening the steam valve in the initial stage of operation, the high-pressure / high-temperature working fluid is balanced between the geothermal capacity and the load. By making a pipe line of the working fluid to be pressed in, heat exchange between the rising steam and the descending liquid working fluid is prevented, and the efficiency is improved. Furthermore, by pressing the working fluid into the lowermost part of the pipe, the working fluid is convected in the reservoir at the bottom of the heat exchanger, and heat exchange is performed smoothly. Equilibrium temperature and pressure are determined by the geotropical capacity and load pressure, but if kept constant, steam can be produced stably for a long time.

  Since the present invention can produce steam by using mid-low temperature geotropics of about 180 ° C. or less distributed overwhelmingly nationwide, geothermal exchange that can increase the geotropics to be used Can be widely used as a system. In addition, geothermal power generation can be realized at many points. In particular, since many power generations at a low pressure with a power generation output of 50 kW or less can be applied, it is not necessary to apply for a cooperative connection with an electric power company and to perform a procedure, thereby contributing to the development of geothermal power generation. In addition, it can be used as a compact geothermal power generation system for areas where transmission lines and distribution lines do not pass.

DESCRIPTION OF SYMBOLS 1 Geothermal exchange system 2 Casing 3 Tube 4 Geotropics 5 Geothermal exchanger 6 Temperature, pressure, flow meter 7 Pressure regulating valve 8 Pressure regulating device 9 Steam valve 10 Heat exchanger 11 Pressurizing pump 12 Working fluid replenishment tank 13 Emergency release valve 14 inner pipe 15 outer pipe 16 lower area 17 middle area 18 upper area 19 cementing 20 turbine 21 condenser

Claims (8)

A geothermal exchanger formed by placing a lower region of a pipe provided in the ground so as to contact the geotropics, a pressure regulator for monitoring and controlling the pressure inside the geothermal exchanger, and a pressure regulator And a pressure regulating valve installed at the top of the geothermal exchanger.
In the operation preparation stage, the geothermal exchanger is pressurized until the pressure in the geothermal exchanger reaches the saturation pressure of the working fluid determined by the temperature of the geotropics, and the working fluid is injected into the geothermal exchanger to exchange geothermal heat. After a high-temperature and high-pressure working fluid is generated and stored in a certain amount without boiling in the vessel, the inside of the geothermal exchanger is depressurized to the heat pressure installed on the ground or the steam pressure required by the turbine A geothermal exchange system characterized in that steam is produced by boiling a part of the high-temperature and high-pressure working fluid.   The geothermal heat exchange system according to claim 1, wherein the pressurization in the geothermal exchanger in the operation preparation stage is performed by press-fitting compressed air into the geothermal exchanger via a pressure regulating valve. .   The taken-out steam is liquefied after being introduced into a heat exchanger installed on the ground or a turbine and exchanging heat, is stored in the bottom of the geothermal exchanger and is heated by the geotropics. Thus, the amount of steam produced is controlled by circulating the working fluid and setting and controlling the pressure of the geothermal exchanger to the steam pressure required by the heat exchanger or turbine. Item 3. A geothermal exchange system according to item 1 or 2.   The inner pipe for lowering the working fluid inside the geothermal exchanger is inserted into the outer pipe constituting the geothermal exchanger, and the inner pipe is the outer pipe in the cross section when the inner pipe is inserted into the outer pipe. The geothermal heat exchange system according to any one of 1 to 3, wherein the geothermal heat exchange system is non-concentric.   The geothermal exchanger includes a lower region that functions as a heat collection / storage zone to which heat is supplied from the earth, an intermediate region that serves as a heat transfer zone for moving the heat obtained in the lower region upward, 5. The geothermal heat exchange system according to claim 1, wherein the intermediate region is formed by a flexible pipe. 5. The geothermal heat exchange system according to claim 1, wherein the intermediate region is formed by a flexible pipe.   The geothermal heat exchange according to any one of claims 1 to 5, wherein the working fluid is injected into the geothermal exchanger by press-fitting the working fluid into the geothermal exchanger with a pressurizing pump. system.   The output side of a plurality of geothermal exchangers is configured to be connected in parallel, and the steam obtained by using each geothermal exchanger is collected in total and collected according to any one of claims 1 to 6. Geothermal exchange system.   A geothermal power generation system that performs power generation using the geothermal exchange system according to any one of claims 1 to 7.

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