JP7320271B2 - Geothermal heat exchangers and geothermal generators - Google Patents

Description

TECHNICAL FIELD The present invention relates to a geothermal heat exchanger and a geothermal power generation device capable of efficiently extracting geothermal energy.

Geothermal power generation, which uses geothermal energy to generate electricity, uses a high-temperature magma layer as a heat source. It has been attracting attention in recent years as an alternative means of fuel. In addition, due to the accident at the nuclear power plant, Japan's energy policy, which relied heavily on nuclear power, has been forced to be fundamentally reviewed, raising expectations for the utilization of geothermal energy.

In conventional geothermal power generation, the geotropical area is drilled, and natural steam and hot water existing in the geotropical area are extracted using natural pressure to generate power. Therefore, the extracted steam and hot water contain a large amount of sulfur and other impurities specific to geotropics. This impurity becomes scale and adheres to thermal wells, pipes, turbines, and the like. If scale adheres, the power generation output will decrease over time, making long-term use difficult.

In order to solve the problem caused by this scale, geothermal heat exchangers that employ a method of sending water from the ground and extracting energy are described in Patent Documents 1 and 2. Further, Patent Document 3 describes an invention relating to a geothermal heat exchanger provided with means for improving the flash rate underground for the purpose of effectively extracting geothermal energy.

Japanese Patent No. 4927136 Japanese Patent No. 5731051 Japanese Patent No. 6176890

All of the methods disclosed in Patent Documents 1, 2, and 3 use a double-tube geothermal heat exchanger buried underground, and the common drawback caused by this is that the temperature of the extracted geothermal energy is There are things that are not constant. In particular, in geothermal development, it is important to develop a geothermal power generation system targeting medium-low temperature zones of approximately 180°C or less, which exist overwhelmingly throughout the country. problems due to the temperature instability of geothermal energy become prominent. Therefore, there arises a problem that the temperature and flow rate of the produced steam are not stable, and the power generation output is not stable. In addition, the fact that geothermal fluid flows in the geotropical zone also causes the geothermal temperature to not stabilize.

It is difficult to find a geothermal fluid that can flow underground and continuously exchange heat, which increases the cost of drilling. In addition, since the temperature of the well decreases after heat exchange, it is necessary to be able to cope with temperature changes in the well when using the well as a heat source.

The present invention has been made in consideration of such circumstances, and even under the condition that the temperature of the extracted geothermal energy is not stable, it is possible to cope with the temperature change of the well, and the It is possible to stabilize the temperature and flow rate of the steam that is used for geothermal development. , a geothermal heat exchanger that enables an increase in the amount of geothermal energy to be extracted, and a geothermal power generation system that uses this geothermal heat exchanger to efficiently generate large-capacity power and effectively utilize the geothermal resources in the power generation area. intended to provide

In order to solve the above problems, the geothermal heat exchanger of the present invention includes an outer pipe that is provided in the ground and is supplied with pressurized water from the ground; and an inner pipe in which hot water generated by supplying heat from the geotropical zone rises in a state where the hot water is generated without containing steam against the pressured water descending to the geotropical zone in the inside, and the pressure water taken out from the inner pipe. is sent to a steam generator and taken out as steam in the steam generator, the geothermal heat exchanger comprising a first flash rate improving means, the first flash rate improving means being the pressure taken out to the ground It is composed of a pressure water heater that heats water, and the heating by the pressure water heater is performed by an external heat source other than the heat source obtained from the geotropical zone, and the pressure water taken out from the inner pipe is heated by the pressure water heater. It is characterized in that it is sent to a steam generator after being processed.

The temperature of the extracted geothermal energy is stabilized by heating the pressurized water taken out to the ground with a pressurized water heater, and heating by the pressurized water heater is done by an external heat source other than the heat source obtained from the geotropical zone. Even if it is not possible, by setting the degree of heating by the pressure water heater according to the temperature of the geothermal energy, the flash rate can be improved and the amount of steam generated can be increased.

Since the pressurized water taken out to the ground has a larger heat capacity than steam, the energy required for heating is greater than when steam is heated. step up. In addition, since the energy required for heating is provided by an external heat source other than the heat source obtained from the geotropics, there is no problem in obtaining thermal energy from the geotropics. Improving the flash rate has a large effect of reducing the amount of circulating water, and the capacity of the well circulation pump can be reduced, greatly improving the power generation efficiency. Further, when the amount of circulating water is kept constant, an improvement in the flash rate directly leads to an increase in the amount of steam, resulting in an increase in power generation output.

Therefore, even when using a medium-low temperature geotropical zone of about 180°C or less, the temperature and flow rate of the high-temperature hot water to be produced can be stabilized, and heat can be efficiently exchanged. By increasing the number, it becomes possible to increase the geothermal energy extraction.

The geothermal heat exchanger of the present invention comprises a booster pump that raises the pressure water taken out from the inner pipe to the ground to increase the pressure, and a well circulation pump that injects circulating water into the outer pipe. can be

The well circulation pump takes charge of the head loss of the double pipe and the head loss of the above-ground pipe, and the booster pump takes charge of the boiling pressure of the pressure water taken out from the double pipe. to prevent cavitation. Smooth control becomes possible by sharing the role of injecting water into and taking out water from the double pipe with two pumps, the well circulation pump and the booster pump, respectively.

In the geothermal heat exchanger of the present invention, a pressure water tank for storing the pressure water taken out from the inner pipe, a pressure water pump for sending the pressure water from the pressure water tank to the pressure water heater, and the pressure water in the pressure water tank Equipped with a pressure water tank pressure water temperature measurement unit that measures the temperature and a pressure water flow rate measurement unit that measures the flow rate of the pressure water. The water flow rate can be controlled and the temperature of the pressure water in the pressure water bath can be controlled.

This makes it possible to control the temperature of the pressurized water, and even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to temperature changes in the geothermal heat and stabilize the temperature and flow rate of the produced steam.

The geothermal heat exchanger of the present invention comprises a first circulating water tank to which condensate obtained by cooling the steam at the turbine outlet and pressurized water excluding the steam boiled under reduced pressure from the steam generator are introduced. , a third flash rate improving means is provided, the third flash rate improving means is constituted by a circulating water heater that heats the water stored in the first circulating water tank, and the heating by the circulating water heater is It can be made by an external heat source other than that obtained from the tropics.

The water stored in the first circulating water tank is heated by the circulating water heater, and the heating by the circulating water heater is performed by an external heat source other than the heat source obtained from the geotropical zone, thereby extracting geothermal energy. Even under conditions where the temperature is not stable, it is possible to improve the flash rate and increase the amount of steam generated by setting the degree of heating by the circulating water heater according to the temperature of the geothermal energy. can.

In the geothermal heat exchanger of the present invention, a transfer water pump that sends pressure water from the steam generator after removing the steam boiled under reduced pressure to the first circulating water tank as transfer water, and a transfer that measures the amount of transfer water a water volume measuring unit, a steam generator pressure water temperature measuring unit that measures the temperature of the pressure water in the steam generator, and a first circulating water temperature that measures the temperature of the circulating water in the first circulating water tank and a measurement unit for controlling the flow rate of the transferred water by controlling the rotation speed of the transferred water pump, and controlling the temperature of the pressure water in the steam generator and the temperature of the circulating water in the first circulating water tank. can be done.

This makes it possible to control the temperature of pressurized water and circulating water, and even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to changes in geothermal temperature and stabilize the temperature and flow rate of produced steam. can.

In the geothermal heat exchanger of the present invention, a second circulating water tank that stores circulating water heated by the circulating water heater, and a second circulating water that measures the temperature of the circulating water in the second circulating water tank A temperature measuring unit and a circulating water amount measuring unit for measuring the amount of circulating water sent from the second circulating water tank to the outer pipe via the well circulating pump. The flow rate of the circulating water sent to the outer pipe can be controlled, and the temperature of the circulating water in the second circulating water tank can be controlled.

This makes it possible to control the temperature of the circulating water, and even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to temperature changes in the geothermal heat and stabilize the temperature and flow rate of the steam produced.

The geothermal heat exchanger of the present invention includes a return water pump that sends return water from the second circulating water tank to the pressure water tank, and a return water amount measuring unit that measures the amount of return water. The flow rate of the return water is controlled by controlling the number, and the temperature of the pressure water in the pressure water tank and the temperature of the circulating water in the second circulating water tank can be controlled.

This makes it possible to control the temperature of pressurized water and circulating water, and even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to changes in geothermal temperature and stabilize the temperature and flow rate of produced steam. can.

Further, the geothermal heat exchanger of the present invention has a double-pipe structure including an outer pipe that is provided underground and is supplied with water from the ground, and an inner pipe that is arranged inside the outer pipe. Equipped with a pressure valve provided inside it, heat is supplied from the geotropical zone to the water in the outer pipe to form a high pressure area where high pressure hot water is generated without boiling, and the pressure valve is installed The pressure valve opens when the pressure difference between the pressure of the high-pressure hot water in the high-pressure area and the decompression area in the inner pipe exceeds the set reference value, and when the pressure valve opens, the high-pressure hot water in the high-pressure area is released. A geothermal heat exchanger that flows into the inner pipe and converts the pressure in the decompression area in the inner pipe to a pressure close to the pressure required by the turbine and converts it into a gas-liquid two-phase flow, and is equipped with a second flash rate improving means. , The second flash rate improving means is composed of a pressure water heater that heats the pressure water obtained by separating steam from the gas-liquid two-phase flow taken above ground, and the heating by the pressure water heater is The pressure water obtained by separating the steam from the gas-liquid two-phase flow by an external heat source other than a heat source obtained from the tropics shall be heated by the pressure water heater and then sent to the steam generator. Characterized by

The pressure water obtained by separating the steam from the gas-liquid two-phase flow taken to the ground is heated by a pressure water heater, and the heating by the pressure water heater is performed by an external heat source other than the heat source obtained from the geotropical zone By doing so, the flash rate can be improved by setting the degree of heating by the pressure water heater according to the temperature of the geothermal energy even under the condition that the temperature of the extracted geothermal energy is not stable. It is possible to increase the amount of steam generation.

Since the gas-liquid two-phase flow extracted above ground has a larger heat capacity than steam, the energy required for heating is greater than when steam is heated. By heating the pressurized water obtained by separation, the flash rate is improved in each step. In addition, since the energy required for heating is provided by an external heat source other than the heat source obtained from the geotropics, there is no problem in obtaining thermal energy from the geotropics. Improving the flash rate has a large effect of reducing the amount of circulating water, and the capacity of the well circulation pump can be reduced, greatly improving the power generation efficiency. Further, when the amount of circulating water is kept constant, an improvement in the flash rate directly leads to an increase in the amount of steam, resulting in an increase in power generation output.

Therefore, even when using a medium-low temperature geotropical zone of about 180°C or less, the temperature and flow rate of the high-temperature hot water to be produced can be stabilized, and heat can be efficiently exchanged. By increasing the number, it becomes possible to increase the geothermal energy extraction.

In the geothermal heat exchanger of the present invention, the gas-liquid two-phase flow tank for storing the gas-liquid two-phase flow taken out from the inner pipe and the pressure water obtained by separating the steam from the gas-liquid two-phase flow are stored in the gas-liquid two-phase flow. a pressurized water pump for sending from the liquid two-phase flow tank to the pressurized water heater; a gas-liquid two-phase flow tank internal pressure water temperature measuring unit for measuring the temperature of the pressurized water in the gas-liquid two-phase flow tank; A pressure water flow rate measuring unit for measuring the flow rate is provided, the flow rate of the pressure water is controlled by controlling the rotation speed of the pressure water pump, and the temperature of the pressure water in the gas-liquid two-phase flow tank is controlled. can be done.

This makes it possible to control the temperature of the pressurized water obtained by separating the steam from the gas-liquid two-phase flow. Steam temperature and flow rate can be stabilized.

The geothermal heat exchanger of the present invention comprises a first circulating water tank to which condensate obtained by cooling the steam at the turbine outlet and pressurized water excluding the steam boiled under reduced pressure from the steam generator are introduced. , a fourth flash rate improving means is provided, the fourth flash rate improving means is constituted by a circulating water heater that heats the water stored in the first circulating water tank, and the heating by the circulating water heater is It can be made by an external heat source other than that obtained from the tropics.

The water stored in the first circulating water tank is heated by the circulating water heater, and the heating by the circulating water heater is performed by an external heat source other than the heat source obtained from the geotropical zone, thereby extracting geothermal energy. Even under conditions where the temperature is not stable, it is possible to improve the flash rate and increase the amount of steam generated by setting the degree of heating by the circulating water heater according to the temperature of the geothermal energy. can.

In the geothermal heat exchanger of the present invention, a transfer water pump that sends pressure water from the steam generator after removing the steam boiled under reduced pressure to the first circulating water tank as transfer water, and a transfer that measures the amount of transfer water a water volume measuring unit, a steam generator pressure water temperature measuring unit that measures the temperature of the pressure water in the steam generator, and a first circulating water temperature that measures the temperature of the circulating water in the first circulating water tank and a measurement unit for controlling the flow rate of the transferred water by controlling the rotation speed of the transferred water pump, and controlling the temperature of the pressure water in the steam generator and the temperature of the circulating water in the first circulating water tank. can be done.

This makes it possible to control the temperature of the pressurized water and circulating water obtained by separating the steam from the gas-liquid two-phase flow. The temperature and flow rate of the produced steam can be stabilized.

In the geothermal heat exchanger of the present invention, a second circulating water tank that stores circulating water heated by the circulating water heater, and a second circulating water that measures the temperature of the circulating water in the second circulating water tank a temperature measuring unit, and a circulating water amount measuring unit for measuring the amount of circulating water sent from the second circulating water tank to the outer pipe via the well circulating pump, and controlling the rotation speed of the well circulating pump can control the flow rate of the circulating water sent to the outer tube, and can control the temperature of the circulating water in the second circulating water tank.

This makes it possible to control the temperature of the circulating water, and even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to temperature changes in the geothermal heat and stabilize the temperature and flow rate of the steam produced.

The geothermal heat exchanger of the present invention includes a return water pump that sends return water from the second circulation water tank to the gas-liquid two-phase flow tank, and a return water amount measuring unit that measures the amount of return water. The flow rate of the return water is controlled by controlling the rotation speed of the water pump, and the temperature of the pressure water in the gas-liquid two-phase flow tank and the temperature of the circulating water in the second circulation water tank are controlled. can be done.

This makes it possible to control the temperature of pressurized water and circulating water, and even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to changes in geothermal temperature and stabilize the temperature and flow rate of produced steam. can.

In the geothermal heat exchanger of the present invention, a steam heater that heats the steam produced by the steam generator, a steam tank that stores the heated steam, and a steam temperature measurement that measures the temperature of the steam in the steam tank and a steam flow rate measuring unit that measures the flow rate of steam. can be used to control the steam temperature and steam flow rate.

This makes it possible to control the temperature of the steam, and even if the geothermal heat is insufficient as a heat source, it is possible to quickly respond to temperature changes in the geothermal heat and stabilize the temperature and flow rate of the produced steam.

In the geothermal heat exchanger of the present invention, the external heat source may be surplus heat from biomass power generation.

In the geothermal heat exchanger of the present invention, the external heat source may be LPG combustion gas.

A geothermal power generation device of the present invention is characterized by generating power using the geothermal heat exchanger of the present invention.

Since the geothermal heat exchanger of the present invention can improve the flash rate, large-capacity power generation is possible. In addition, even when geothermal heat is insufficient as a heat source, it is possible to quickly respond to changes in geothermal temperature, thereby stabilizing power generation output.

According to the present invention, even under conditions where the temperature of the extracted geothermal energy is not stable, it is possible to cope with changes in the temperature of the well, thereby stabilizing the temperature and flow rate of the produced steam. Efficient heat exchange is possible even when using medium-low temperature geotropics of about 180°C or less, making it possible to increase the number of locations subject to geothermal development and increase the amount of geothermal energy harvested. It is possible to realize a geothermal power generator that can efficiently generate large-capacity power using the geothermal heat exchanger and effectively utilize the geothermal resources in the power generation area.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the geothermal exchanger and geothermal power generation apparatus which concern on 1st embodiment of this invention. FIG. 4 is a diagram showing the configuration of a geothermal heat exchanger and a geothermal power generation device according to a second embodiment of the present invention; FIG. 3 is a diagram showing the configuration of a geothermal heat exchanger and a geothermal power generation device according to a third embodiment of the present invention; FIG. 5 is a diagram showing the configuration of a geothermal heat exchanger and a geothermal power generation device according to a fourth embodiment of the present invention;

A geothermal heat exchanger and a geothermal power generation device according to the present invention will be described below based on embodiments thereof.
FIG. 1 shows the configuration of a geothermal heat exchanger and a geothermal power generator according to the first embodiment of the present invention.

The geothermal heat exchanger 1 is arranged in an outer pipe 2 that is provided in the ground and supplied with water pressurized by a well circulation pump 9, and is arranged inside the outer pipe 2, and extends through the outer pipe 2 to the geotropical zone. It has an inner pipe 3 in which hot water generated by supplying heat from the geotropical zone to the descending pressure water rises without steam. The pressure water extracted from the inner pipe 3 is sent to the steam generator 10 and extracted as steam within the steam generator 10 . A heat insulating portion 20 is formed at a location where the outer tube 2 contacts a low-temperature zone near the ground surface.

The geothermal heat exchanger 1 is provided with a first flash rate improving means. The first flash rate improving means is composed of a pressure water heater 14 for heating the pressure water taken to the ground, and the heating by the pressure water heater 14 is performed by an external heat source other than the heat source obtained from the geotropical zone. . Therefore, the pressure water taken out from the inner pipe 3 is heated by the pressure water heater 14 and then sent to the steam generator 10 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used. The steam generated by the steam generator 10 passes through the separator 11 and is introduced into the high pressure section of the turbine 12 to drive the turbine 12 and generate electricity by the generator.

The steam exiting the turbine 12 is then cooled back to water in the condenser 18 by cooling water. Condensate obtained by cooling the steam at the outlet of the turbine 12 is led to the first circulation water tank 16 . Moreover, pressure water from which steam boiled under reduced pressure is removed from the steam generator 10 is led to the first circulation water tank 16 through the separator 11 .

The geothermal heat exchanger 1 is provided with a third flash rate improving means, and the third flash rate improving means is composed of a circulating water heater 17 that heats the water stored in the first circulating water tank 16, Heating by the circulating water heater 17 is performed by an external heat source other than the heat source obtained from the geotropics. As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used.

The water in the first circulating water tank 16 heated by the circulating water heater 17 is pressurized by the well circulation pump 9 and supplied to the outer tube 2 again. By repeating this process, geothermal heat is extracted continuously.

FIG. 2 shows the configuration of a geothermal heat exchanger and a geothermal power generator according to a second embodiment of the present invention.
The geothermal heat exchanger 1 has a double-pipe structure including an outer pipe 2 that is provided underground and is supplied with water from the ground, and an inner pipe 3 that is arranged inside the outer pipe 2. The inner pipe 3 is It has a pressure valve 6 provided therein. A high-pressure area 5 is formed in which heat is supplied from the geotropical zone to the water in the outer tube 2 to generate high-pressure hot water without boiling. When the pressure difference between the pressure of the high-pressure hot water and the pressure reduction area 8 in the inner pipe 3 exceeds a set reference value, the pressure valve 6 is opened, and when the pressure valve 6 is opened, the high-pressure hot water is introduced from the high-pressure area 5. Entering the tube 3, the upper portion of the reduced pressure area 8 of the inner tube 3 is decompressed to near the pressure required by the turbine and converted to a gas-liquid two-phase flow. The pressure valve 6 is opened by setting the pressure for pressurizing the water injected into the outer tube 2 by the well circulation pump 9 . A heat insulating portion 20 is formed at a location where the outer tube 2 contacts a low-temperature zone near the ground surface.

The reference value for opening the pressure valve 6 is set by setting the pressure of the high-pressure hot water in the high-pressure area 5 at the position where the pressure valve 6 is installed as the saturation pressure at the water saturation temperature determined from the temperature conditions of the geotropical zone. , the pressure valve 6 can be opened beyond a set reference value of the pressure difference.

Further, the reference value for opening the pressure valve 6 is set by setting the pressure of the high-pressure hot water in the high-pressure area 5 at the position where the pressure valve 6 is installed to the vicinity of the critical pressure of the water, and setting the reference value for the pressure difference. It is also possible for the pressure valve 6 to open beyond.

The geothermal heat exchanger 1 is equipped with a second flash rate improving means. The second flash rate improving means is composed of a pressure water heater 15 that heats the pressure water obtained by separating steam from the gas-liquid two-phase flow taken to the ground, and the heating by the pressure water heater 15 is by an external heat source other than heat derived from the geotropics. Therefore, the pressure water obtained by separating the steam from the gas-liquid two-phase flow is heated by the pressure water heater 15 and then sent to the steam generator 10 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used. The steam generated by the steam generator 10 is introduced into the high pressure section of the turbine 12, drives the turbine 12, and the generator generates electricity.

The steam exiting the turbine 12 is then cooled back to water in the condenser 18 by cooling water. Condensate obtained by cooling the steam at the outlet of the turbine 12 is led to the first circulation water tank 16 . Moreover, pressure water from which steam boiled under reduced pressure is removed from the steam generator 10 is led to the first circulation water tank 16 through the separator 11 .

The geothermal heat exchanger 1 is provided with a fourth flash rate improving means, and the fourth flash rate improving means is composed of a circulating water heater 17 that heats the water stored in the first circulating water tank 16, Heating by the circulating water heater 17 is performed by an external heat source other than the heat source obtained from the geotropics. As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used.

The water in the first circulating water tank 16 heated by the circulating water heater 17 is pressurized by the well circulation pump 9 and supplied to the outer tube 2 again. By repeating this process, geothermal heat is extracted continuously.

Specific examples are shown below.
As a conventional example, the pressure water temperature in Patent Document 1 (Patent No. 4927136) is 160 ° C. and the generated steam temperature is 130 ° C., and the pressure water in the first embodiment of the present invention Example 1 is that the temperature is heated by the pressure water heater 14 to 180° C. and the generated steam temperature is 130° C. In the first embodiment of the present invention, the circulating water temperature is set to the circulating water heater 17 was heated to 180.degree.

In the present invention, since steam production utilizes the physical phenomenon of boiling under reduced pressure, it is important to increase the temperature difference between pressure water and steam to increase the flash rate.
Table 1 shows a saturated steam table, and Table 2 shows a flash rate table in the temperature range in the present invention. The flash rate is displayed in %. The formula is
(High temperature saturated water h″−Low temperature saturated water h″)/Low temperature latent heat of vaporization is used.

Under atmospheric pressure, water turns into steam at 100° C., but in a region pressurized above atmospheric pressure, it can exist as pressure water up to a temperature that matches the pressure. When the pressure in the region of pressure water is lowered, the pressure water releases part of the enthalpy, lowers the temperature to a level corresponding to the pressure reduction, and equilibrates. This physical phenomenon is called decompression boiling, and it is a mechanism that generates steam corresponding to the decompression. Many geothermal power plants in geothermal fields take natural pressurized water and boil it under reduced pressure to produce steam. When pressurized water is boiled under reduced pressure, not only steam but also pressurized hot water are produced at the same time, and the ratio of this steam is called flash rate. To produce steam by boiling under reduced pressure, there is a method of raising the temperature of the pressure water or lowering the temperature of the steam. Since lowering the steam temperature is not suitable for power generation, it is rational to raise the temperature of the pressurized water to increase the flash rate and increase the steam production.

From the above point of view, the present invention aims to improve the flash rate.
Based on the flash rate formula,
(Latent heat of high-temperature pressure water - latent heat of low-temperature pressure water) / When high-temperature pressure water of 160 ° C. is boiled under reduced pressure (flash) at 140 ° C. using the latent heat of evaporation of low-temperature pressure water, the flash rate is 4.0%. becomes.

If the flash rate can be increased, the amount of circulating water can be reduced when the amount of steam required by the turbine is constant, and the amount of steam produced can be increased when the amount of circulating water is constant. can be done. In the present invention, the flash rate can be increased by using an external heat source other than geothermal heat to raise the temperature of the pressure water or circulating water. In the following, consideration will be given from these two viewpoints. In the following description, circulating water may be referred to as circulating water including pressurized water from the meaning of water circulating in the geothermal heat exchanger, and the amount of water is defined as the amount of circulating water.

First, the case where the amount of steam required by the turbine is fixed will be described.
Table 3 shows the steam conditions.

Table 4 shows the flash rate, the amount of circulating water, and the capacity required for heating for the conventional example, Example 1, and Example 2.

Table 5 shows the calculation of the amount of heat required to heat the pressurized water at 160°C to 180°C.

The required capacity of the pressure water heater is
(circulating water volume x ((latent heat of high temperature pressure water) - (latent heat of low temperature pressure))
is sought by The temperatures of the circulating water and the pressure water are assumed to be in a constant proportional relationship, and the steam temperature is kept constant.

Since the amount of circulating water changes depending on the flush rate, the capacity of the well circulation pump is calculated.
Table 6 shows each numerical value of the double tube to be used.

As conditions, the boiling pressure was increased and the pump efficiency was 80%. The well depth is 500m, and the inner pipe adds 10% of head loss above ground. Darcy-Weisbach's formula was adopted as the formula for the head loss. The calculated head loss values are shown in Table 7.

Table 8 shows the calculated pump capacity.

Since the amount of circulating water can be reduced in this way, the capacity of the well circulation pump used for pressurization can be reduced.

Next, a case where the amount of circulating water is kept constant will be described.
The steam conditions shown in Table 3, the capacities required for heating shown in Tables 4 and 5 are the same here, and Table 9 shows the calculation of the power output.

Here, the power generation value is assumed to be proportional to the amount of steam. It has been shown to be effective, with power generation figures exceeding those required for heating.

Table 10 summarizes data showing the effects of the present invention.

According to the present invention, since the flash rate is greatly improved, the effect of reducing the pump capacity is large and exceeds the capacity required for heating. Therefore, it can be said that the effect of the present invention is very large. It is preferably applied to power generation of 500 kW or more.

Thus, increasing the flash rate has a large effect of reducing the amount of circulating water, significantly reducing the capacity of the well circulation pump, and greatly improving the power generation efficiency. Further, if the circulating water volume is kept constant, an increase in the flash rate directly leads to an increase in the amount of steam, resulting in an increase in power generation output. As a means for raising the temperature of circulating water or pressure water, it is effective to use an external heat source, the most prominent example of which is the use of surplus heat from biomass power generation.

In the above explanation, the case of heating pressurized water is studied, but the same principle can be used to improve the flash rate even when heating a gas-liquid two-phase flow, and the same effect can be obtained. can be done.

The geothermal heat exchanger and the geothermal power generator of the present invention will be described below with respect to a third embodiment and a fourth embodiment, which are provided with temperature control means.
FIG. 3 shows the configuration of a geothermal heat exchanger and a geothermal power generator according to a third embodiment of the present invention.
The geothermal heat exchanger 1 is arranged in an outer pipe 2 that is provided in the ground and supplied with water pressurized by a well circulation pump 9, and is arranged inside the outer pipe 2, and extends through the outer pipe 2 to the geotropical zone. It has an inner pipe 3 in which hot water generated by supplying heat from the geotropical zone to the descending pressure water rises without steam. The pressure water extracted from the inner pipe 3 is sent to the steam generator 10 and extracted as steam within the steam generator 10 . A heat insulating portion 20 is formed at a location where the outer tube 2 contacts a low-temperature zone near the ground surface.

The pressure water taken out from the inner pipe 3 via the booster pump 45 is stored in the pressure water tank 22 and sent to the pressure water heater 14 by the pressure water pump 21 . A pressure water tank pressure water temperature measurement unit 32 for measuring the temperature of the pressure water in the pressure water tank 22 and a pressure water flow rate measurement unit 31 for measuring the flow rate of the pressure water are provided. According to the temperature, the flow rate of the pressure water is controlled by controlling the rotation speed of the pressure booster pump 45 and the rotation speed of the pressure water pump 21, and the pressure in the pressure water tank 22 is adjusted so that the pressure water temperature reaches the set value. Water temperature is controlled.

Sufficient volume is stored in pressure water tank 22 to accommodate temperature variations in the well. The pressure water stored in the pressure water tank 22 is taken out by the pressure water pump 21 in an amount determined by the flash rate calculated based on the steam flow rate, steam temperature and steam pressure.

The geothermal heat exchanger 1 is provided with a first flash rate improving means. The first flash rate improving means is composed of a pressure water heater 14 that heats the pressure water taken to the ground, and the heating by the pressure water heater 14 is performed by an external heat source other than the heat source obtained from the geotropical zone, by the combustion gas stream obtained from the combustion furnace 30; As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used. Therefore, the pressure water taken out from the inner pipe 3 is heated by the pressure water heater 14 and then sent to the steam generator 10 . The steam generated by the steam generator 10 passes through the separator 11 and is introduced into the high pressure section of the turbine 12 to drive the turbine 12 and generate electricity by the generator 13 . A generator output measuring unit 35 is attached to the generator 13, and the voltage, current, power factor, etc. of the generator 13 are measured, monitored, and recorded.

The steam that has passed through the separator 11 can be converted from saturated steam to superheated steam by the steam heater 23 , thereby improving the efficiency of the turbine 12 . The superheated steam sets the steam pressure below the critical pressure, which allows the employment of high temperature turbines, which is not the case in conventional geothermal power generation.

Heating by the steam heater 23 is provided by an external heat source other than the heat source obtained from the geothermal heat and is provided by the combustion gas stream obtained from the combustion furnace 30 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used. The superheated steam is introduced into the turbine 12 through the steam tank 24 and the steam valve 26 to drive the turbine 12 and generate electricity by the generator 13 . A steam flow rate measuring unit 25 for measuring the steam flow rate is attached to the steam flow path, and a steam temperature measuring unit 34 for measuring the temperature of the steam in the steam bath 24 is attached to the steam bath 24 . The steam temperature and steam flow rate are controlled according to the steam temperature and steam flow rate in the steam bath 24 .

The steam exiting the turbine 12 is then cooled back to water in the condenser 18 by cooling water. A supplementary water tank 29 is connected to the condenser 18, and treated water is supplied to the supplementary water tank 29 from the water treatment apparatus. A condensate temperature measuring unit 40 for measuring the temperature of condensate and a condensate flow rate measuring unit 41 for measuring the flow rate of condensate are attached. Condensate obtained by cooling the steam at the outlet of the turbine 12 is led to the first circulation water tank 16 . Moreover, pressure water from which steam boiled under reduced pressure is removed from the steam generator 10 is led to the first circulation water tank 16 through the separator 11 .

The geothermal heat exchanger 1 is provided with a third flash rate improving means, and the third flash rate improving means is composed of a circulating water heater 17 that heats the water stored in the first circulating water tank 16, Heating by the circulating water heater 17 is performed by an external heat source other than the heat source obtained from the geothermal heat, and is performed by the combustion gas flow obtained from the combustion furnace 30 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used.

The pressurized water from the steam generator 10 excluding the steam boiled under reduced pressure is sent to the first circulation water tank 16 as transfer water by the transfer water pump 27 . A transferred water amount measuring unit 37 for measuring the amount of transferred water, a steam generator internal pressure water temperature measuring unit 33 for measuring the temperature of the pressure water in the steam generator 10, and the circulating water in the first circulating water tank 16. A first circulating water temperature measuring unit 36 for measuring the temperature is provided, and according to the temperature of the pressure water in the steam generator 10 and the temperature of the circulating water in the first circulating water tank 16, The flow rate of transferred water is controlled by controlling the rotation speed of 27 so that the temperature of the pressure water in the steam generator 10 and the temperature of the circulating water in the first circulating water tank 16 are set to the set values. The temperature of the pressurized water in the generator 10 and the temperature of the circulating water in the first circulating water tank 16 are controlled.

The circulating water heated by the circulating water heater 17 is stored in the second circulating water tank 19 , and the return water from the second circulating water tank 19 is sent to the pressure water tank 22 by the return water pump 28 . A return water amount measuring unit 38 for measuring the amount of returned water and a second circulating water temperature measuring unit 39 for measuring the temperature of the circulating water in the second circulating water tank 19 are provided. The flow rate of the return water is controlled by controlling the rotation speed of the return water pump 28 according to the temperature of the water and the temperature of the circulating water in the second circulating water tank 19, and the temperature of the pressure water in the pressure water tank 22 and the , the temperature of the pressurized water in the pressure water tank 22 and the temperature of the circulating water in the second circulating water tank 19 are controlled so that the temperature of the circulating water in the second circulating water tank 19 becomes the set value. The return water pump 28 forms a closed circuit bypassing to the pressure water tank 22, and is effective as a means of dealing with reduced well capacity.

The circulating water in the second circulating water tank 19 is sent to the outer pipe 2 by the well circulation pump 9 . By repeating this process, geothermal heat is extracted continuously. A discharge valve 46 is attached between the well circulation pump 9 and the outer pipe 2 . Equipped with a circulating water amount measuring unit 43 that measures the amount of circulating water sent to the outer tube 2, and according to the temperature of the circulating water in the second circulating water tank 19, by controlling the rotation speed of the well circulation pump 9 The flow rate of the circulating water sent to the outer tube 2 is controlled, and the temperature of the circulating water in the second circulating water tank 19 is controlled so that the temperature of the circulating water in the second circulating water tank 19 reaches the set value. .

The well circulation pump 9 takes charge of the head loss of the double pipe and the head loss of the aboveground pipe. By combining PID (Proportional Integral Control) control incorporated in the measurement system and rotational speed control by an inverter, the well circulation pump 9 can guarantee the time delay of the control. Similar control is possible for other pumps used in the present invention.

A booster pump 45 for increasing the pressure of the pressure water taken out from the inner pipe 3 prevents cavitation of the well circulation pump 45 by taking charge of the boiling pressure of the pressure water taken out from the double pipe. Smooth control becomes possible by sharing the role of injecting water into and taking out water from the double pipe by two pumps, the well circulation pump 9 and the booster pump 45, respectively.

With the temperature control described above, even when geothermal heat is insufficient as a heat source, changes in geothermal temperature can be quickly dealt with, and power output is stabilized. In addition, the operation of the pump is stabilized, and long-term operation becomes possible. Therefore, it is possible to select a large-capacity device for both steam temperature and pressure, and to perform large-capacity and stable power generation.

FIG. 4 shows the configuration of a geothermal heat exchanger and a geothermal power generator according to a fourth embodiment of the present invention.
The geothermal heat exchanger 1 has a double-pipe structure including an outer pipe 2 that is provided underground and is supplied with water from the ground, and an inner pipe 3 that is arranged inside the outer pipe 2. The inner pipe 3 is It has a pressure valve 6 provided therein. A high-pressure area 5 is formed in which heat is supplied from the geotropical zone to the water in the outer tube 2 to generate high-pressure hot water without boiling. When the pressure difference between the pressure of the high-pressure hot water and the pressure reduction area 8 in the inner pipe 3 exceeds a set reference value, the pressure valve 6 is opened, and when the pressure valve 6 is opened, the high-pressure hot water is introduced from the high-pressure area 5. Entering the tube 3, the upper portion of the reduced pressure area 8 of the inner tube 3 is decompressed to near the pressure required by the turbine and converted to a gas-liquid two-phase flow. The pressure valve 6 is opened by setting the pressure for pressurizing the water injected into the outer tube 2 by the well circulation pump 9 . A heat insulating portion 20 is formed at a location where the outer tube 2 contacts a low-temperature zone near the ground surface.

The reference value for opening the pressure valve 6 is set by setting the pressure of the high-pressure hot water in the high-pressure area 5 at the position where the pressure valve 6 is installed as the saturation pressure at the water saturation temperature determined from the temperature conditions of the geotropical zone. , the pressure valve 6 can be opened beyond a set reference value of the pressure difference.

Further, the reference value for opening the pressure valve 6 is set by setting the pressure of the high-pressure hot water in the high-pressure area 5 at the position where the pressure valve 6 is installed to the vicinity of the critical pressure of the water, and setting the reference value for the pressure difference. It is also possible for the pressure valve 6 to open beyond.

The gas-liquid two-phase flow taken out from the inner tube 3 is stored in a gas-liquid two-phase flow tank 50, and the pressure water obtained by separating steam from the gas-liquid two-phase flow is pumped by a pressure water pump 52. It is sent to the water heater 15 . A gas-liquid two-phase flow tank pressure water temperature measurement unit 51 for measuring the temperature of the pressure water in the gas-liquid two-phase flow tank 50, and a pressure water flow rate measurement unit 53 for measuring the flow rate of the pressure water, According to the temperature of the pressure water in the gas-liquid two-phase flow tank 50, the flow rate of the pressure water is controlled by controlling the rotation speed of the pressure water pump 52, and the gas-liquid two-phase flow is controlled so that the pressure water temperature reaches the set value. The temperature of the pressurized water in flow bath 50 is controlled. The steam separated from the gas-liquid two-phase flow is sent to the steam heater 23 .

The geothermal heat exchanger 1 is equipped with a second flash rate improving means. The second flash rate improving means is composed of a pressure water heater 15 that heats the pressure water obtained by separating steam from the gas-liquid two-phase flow taken to the ground, and the heating by the pressure water heater 15 is It is provided by an external heat source other than the heat source obtained from the geotropical zone and by the combustion gas stream obtained from the combustion furnace 30 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used. Therefore, the pressure water obtained by separating the steam from the gas-liquid two-phase flow is heated by the pressure water heater 15 and then sent to the steam generator 10 . The steam generated by the steam generator 10 passes through the separator 11 and is introduced into the high pressure section of the turbine 12 to drive the turbine 12 and generate electricity by the generator 13 . A generator output measuring unit 35 is attached to the generator 13 .

The steam that has passed through the separator 11 can be converted from saturated steam to superheated steam by the steam heater 23 , thereby improving the efficiency of the turbine 12 . Heating by the steam heater 23 is provided by an external heat source other than the heat source obtained from the geothermal heat and is provided by the combustion gas stream obtained from the combustion furnace 30 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used.

The superheated steam is introduced into the turbine 12 through the steam tank 24 and the steam valve 26 to drive the turbine 12 and generate electricity by the generator 13 . A steam flow rate measuring unit 25 for measuring the steam flow rate is attached to the steam flow path, and a steam temperature measuring unit 34 for measuring the temperature of the steam in the steam bath 24 is attached to the steam bath 24 . The steam temperature and steam flow rate are controlled according to the steam temperature and steam flow rate in the steam bath 24 .

The steam exiting the turbine 12 is then cooled back to water in the condenser 18 by cooling water. A supplementary water tank 29 is connected to the condenser 18, and treated water is supplied to the supplementary water tank 29 from the water treatment apparatus. A condensate temperature measuring unit 40 for measuring the temperature of condensate and a condensate flow rate measuring unit 41 for measuring the flow rate of condensate are attached. Condensate obtained by cooling the steam at the outlet of the turbine 12 is led to the first circulation water tank 16 . Moreover, pressure water from which steam boiled under reduced pressure is removed from the steam generator 10 is led to the first circulation water tank 16 through the separator 11 .

The geothermal heat exchanger 1 is provided with a fourth flash rate improving means, and the fourth flash rate improving means is composed of a circulating water heater 17 that heats the water stored in the first circulating water tank 16, Heating by the circulating water heater 17 is performed by an external heat source other than the heat source obtained from the geothermal heat, and is performed by the combustion gas flow obtained from the combustion furnace 30 . As an external heat source, the surplus heat of biomass power generation can be used, in addition the combustion gas stream from LPG can be used.

The pressurized water from the steam generator 10 excluding the steam boiled under reduced pressure is sent to the first circulation water tank 16 as transfer water by the transfer water pump 27 . A transferred water amount measuring unit 37 for measuring the amount of transferred water, a steam generator pressure water temperature measuring unit 54 for measuring the temperature of the pressure water in the steam generator 10, and the circulating water in the first circulating water tank 16. A first circulating water temperature measuring unit 36 for measuring the temperature is provided, and according to the temperature of the pressure water in the steam generator 10 and the temperature of the circulating water in the first circulating water tank 16, The flow rate of transferred water is controlled by controlling the rotation speed of 27 so that the temperature of the pressure water in the steam generator 10 and the temperature of the circulating water in the first circulating water tank 16 are set to the set values. The temperature of the pressurized water in the generator 10 and the temperature of the circulating water in the first circulating water tank 16 are controlled.

The circulating water heated by the circulating water heater 17 is stored in the second circulating water tank 19, and the return water from the second circulating water tank 19 is sent to the gas-liquid two-phase flow tank 50 by the return water pump 28. . The gas-liquid two-phase flow tank is provided with a returned water amount measuring unit 38 for measuring the amount of returned water and a second circulating water temperature measuring unit 39 for measuring the temperature of the circulating water in the second circulating water tank 19. The flow rate of the return water is controlled by controlling the rotation speed of the return water pump 28 according to the temperature of the pressure water in 50 and the temperature of the circulating water in the second circulating water tank 19, and the gas-liquid two-phase flow tank The temperature of the pressure water in the gas-liquid two-phase flow tank 50 and the temperature of the pressure water in the second circulation water tank 19 are adjusted so that the temperature of the pressure water in the gas-liquid two-phase flow tank 50 and the temperature of the pressure water in the second circulation water tank 19 are equal to the set values. The temperature of the circulating water inside is controlled. The return water pump 28 forms a closed circuit that bypasses the gas-liquid two-phase flow tank 50, and is effective as a means for dealing with reduced well capacity.

The circulating water in the second circulating water tank 19 is sent to the outer pipe 2 by the well circulation pump 9 . By repeating this process, geothermal heat is extracted continuously. A discharge valve 46 is attached between the well circulation pump 9 and the outer pipe 2 . Equipped with a circulating water amount measuring unit 43 that measures the amount of circulating water sent to the outer tube 2, and according to the temperature of the circulating water in the second circulating water tank 19, by controlling the rotation speed of the well circulation pump 9 The flow rate of the circulating water sent to the outer tube 2 is controlled, and the temperature of the circulating water in the second circulating water tank 19 is controlled so that the temperature of the circulating water in the second circulating water tank 19 reaches the set value. . The discharge valve 46 is closed at the beginning of operation and is controlled to be fully open during operation, thereby preventing cavitation of the well circulation pump 9 .

Also in this embodiment, due to the above-described temperature control, even if geothermal heat is insufficient as a heat source, it is possible to quickly respond to changes in geothermal temperature, and the power output is stabilized. In addition, the operation of the pump is stabilized, and long-term operation becomes possible. Therefore, it is possible to select a large-capacity device for both steam temperature and pressure, and to perform large-capacity and stable power generation.

Information collected by various temperature measurement units, flow rate measurement units, and generator output measurement units used in the above-described third and fourth embodiments is transmitted to the control unit of the control center via the network, Temperature and flow are controlled and managed. By controlling and managing the temperature and the flow rate in this way, even under conditions where the well temperature is not stable, it is possible to improve the flash rate in response to changes in the temperature of the well.

The present invention makes it possible to cope with temperature changes in wells even when the temperature of the extracted geothermal energy is not stable, and stabilizes the temperature and flow rate of the produced steam. Geothermal heat that can efficiently exchange heat even in a medium-low temperature geotropical zone of about 180°C or less, and that can increase the amount of geothermal energy extraction by increasing the number of locations subject to geothermal development. It can be widely used as a geothermal power generator capable of efficiently using the geothermal heat exchanger to generate large-capacity power and making effective use of the geothermal resources in the power generation area.

1 geothermal heat exchanger 2 outer tube 3 inner tube 5 high pressure area 6 pressure valve 8 pressure reduction area 9 well circulation pump 10 steam generator 11 separator 12 turbine 13 generator 14 pressure water heater 15 pressure water heater 16 first circulation Water tank 17 Circulating water heater 18 Condenser 19 Second circulating water tank 20 Heat insulating part 21 Pressure water pump 22 Pressure water tank 23 Steam heater 24 Steam tank 25 Steam flow rate measuring part 26 Steam valve 27 Transfer water pump 28 Return water pump 29 Make-up water tank 30 Combustion furnace 31 Pressure water flow rate measurement unit 32 Pressure water water temperature measurement unit in pressure water tank 33 Pressure water temperature measurement unit in steam generator 34 Steam temperature measurement unit in steam tank 35 Generator output measurement unit 36 First circulating water Temperature measurement unit 37 Transfer water amount measurement unit 38 Return water amount measurement unit 39 Second circulating water temperature measurement unit 40 Condensate temperature measurement unit 41 Condensate flow rate measurement unit 43 Circulation water amount measurement unit 45 Booster pump 46 Discharge valve 50 Gas-liquid 2 Phase flow tank 51 Pressure water temperature measurement unit in gas-liquid two-phase flow tank 52 Pressure water pump 53 Pressure water flow rate measurement unit 54 Pressure water temperature measurement unit in steam generator

Claims (14)

an outer pipe provided in the ground to which water pressurized from the ground is supplied; and heat from the geotropical zone disposed inside the outer pipe to the pressure water descending in the outer pipe to the geotropical zone. and an inner pipe that rises in a state in which hot water generated by being supplied does not contain steam, and pressure water taken out from the inner pipe is sent to a steam generator and taken out as steam in the steam generator. A geothermal heat exchanger that is equipped with a first flash rate improving means, the first flash rate improving means is composed of a pressure water heater that heats the pressure water taken out to the ground, and the pressure water heater Heating is performed by an external heat source other than the heat source obtained from the geotropical zone, and the pressure water taken out from the inner pipe is heated by the pressure water heater and then sent to the steam generator,
A booster pump that raises the pressure water taken out from the inner pipe to the ground to increase the pressure, and a well circulation pump that injects circulating water into the outer pipe,
A pressure water tank for storing the pressure water taken out from the inner pipe, a pressure water pump for sending the pressure water from the pressure water tank to the pressure water heater, and pressure water in the pressure water tank for measuring the temperature of the pressure water in the pressure water tank. Equipped with a temperature measurement unit and a pressure water flow rate measurement unit that measures the flow rate of pressure water. A geothermal heat exchanger, wherein the temperature of the pressure water is controlled . A first circulating water tank to which condensate obtained by cooling the steam at the turbine outlet and pressure water obtained by removing the steam boiled under reduced pressure from the steam generator are introduced, and a third flash rate improving means. The third flash rate improving means is composed of a circulating water heater that heats the water stored in the first circulating water tank, and the heating by the circulating water heater is an external heat source other than the heat source obtained from the geotropical zone. The geothermal heat exchanger according to claim 1 , characterized in that it is made by a transfer water pump for sending pressurized water from the steam generator excluding steam boiled under reduced pressure to the first circulating water tank as transfer water; a transfer water amount measuring unit for measuring the amount of transfer water; and the steam generator. a steam generator internal pressure water temperature measuring unit for measuring the temperature of the pressure water inside the steam generator; and a first circulating water temperature measuring unit for measuring the temperature of the circulating water in the first circulating water tank; The flow rate of transferred water is controlled by controlling the rotational speed of the steam generator, and the temperature of the pressure water in the steam generator and the temperature of the circulating water in the first circulating water tank are controlled. geothermal heat exchanger. a second circulating water tank for storing the circulating water heated by the circulating water heater; a second circulating water temperature measuring unit for measuring the temperature of the circulating water in the second circulating water tank; and a well circulation pump a circulating water amount measuring unit for measuring the amount of circulating water sent from the second circulating water tank to the outer pipe via the is controlled to control the temperature of the circulating water in the second circulating water tank. A return water pump that sends return water from the second circulating water tank to the pressure water tank, and a return water amount measuring unit that measures the amount of return water, and the flow rate of the return water is controlled by controlling the rotation speed of the return water pump. 5. The geothermal heat exchanger according to claim 4 , wherein the temperature of the pressure water in the pressure water tank and the temperature of the circulating water in the second circulating water tank are controlled. It has a double-pipe structure comprising an outer pipe provided underground to which water is supplied from the ground, and an inner pipe disposed inside the outer pipe, the inner pipe having a pressure valve provided therein. A high-pressure area is formed in which heat is supplied from the geotropical zone to the water in the outer pipe to generate high-pressure hot water without boiling, and high-pressure hot water in the high-pressure area at the position where the pressure valve is installed. When the pressure difference between the pressure in the inner pipe and the decompression area in the inner pipe exceeds the set reference value, the pressure valve opens. A geothermal heat exchanger in which the pressure in the area is reduced to a pressure close to that required by the turbine and converted to a gas-liquid two-phase flow, the geothermal heat exchanger comprising a second flash rate enhancing means, the second flash rate enhancing means comprising: It consists of a pressurized water heater that heats pressurized water obtained by separating steam from the gas-liquid two-phase flow taken above ground. The pressure water obtained by separating the steam from the gas-liquid two-phase flow is heated by the pressure water heater and then sent to the steam generator ,
a gas-liquid two-phase flow tank for storing the gas-liquid two-phase flow extracted from the inner tube; and pressurized water obtained by separating steam from the gas-liquid two-phase flow. A pressure water pump to send to the heater, a pressure water temperature measurement unit for measuring the temperature of the pressure water in the gas-liquid two-phase flow tank, and a pressure water flow measurement unit for measuring the flow rate of the pressure water. wherein the flow rate of the pressure water is controlled by controlling the rotation speed of the pressure water pump, and the temperature of the pressure water in the gas-liquid two-phase flow tank is controlled. A first circulating water tank to which condensate obtained by cooling the steam at the turbine outlet and pressure water obtained by removing the steam boiled under reduced pressure from the steam generator are introduced, and a fourth flash rate improving means. The fourth flash rate improving means is composed of a circulating water heater that heats the water stored in the first circulating water tank, and the heating by the circulating water heater is an external heat source other than the heat source obtained from the geotropical zone. The geothermal heat exchanger according to claim 6 , characterized in that it is made by a transfer water pump for sending pressurized water from the steam generator excluding steam boiled under reduced pressure to the first circulating water tank as transfer water; a transfer water amount measuring unit for measuring the amount of transfer water; and the steam generator. a steam generator internal pressure water temperature measuring unit for measuring the temperature of the pressure water inside the steam generator; and a first circulating water temperature measuring unit for measuring the temperature of the circulating water in the first circulating water tank; 8. The temperature of the pressure water in the steam generator and the temperature of the circulating water in the first circulating water tank are controlled by controlling the rotation speed of the steam generator. geothermal heat exchanger. a second circulating water tank for storing the circulating water heated by the circulating water heater; a second circulating water temperature measuring unit for measuring the temperature of the circulating water in the second circulating water tank; and a well circulation pump a circulating water amount measuring unit for measuring the amount of circulating water sent from the inside of the second circulating water tank to the outer pipe through the 9. The geothermal heat exchanger according to claim 7, wherein the flow rate of is controlled, and the temperature of the circulating water in the second circulating water tank is controlled. A return water pump that sends return water from the second circulating water tank to the gas-liquid two-phase flow tank, and a return water amount measuring unit that measures the amount of return water. 10. The geothermal heat exchanger according to claim 9 , characterized in that the flow rate of water is controlled, and the temperature of the pressure water in the gas-liquid two-phase flow tank and the temperature of the circulating water in the second circulating water tank are controlled. . A steam heater that heats the steam produced by the steam generator, a steam tank that stores the heated steam, a steam temperature measuring unit that measures the temperature of the steam in the steam tank, and a steam flow rate that measures the flow rate of the steam. Heating by the steam heater is performed by an external heat source other than the heat source obtained from the geotropical zone, and the steam temperature and steam flow rate are controlled according to the steam temperature and steam flow rate in the steam bath. The geothermal heat exchanger according to any one of claims 1 to 10 , characterized in that: The geothermal heat exchanger according to any one of claims 1 to 11 , wherein the external heat source is surplus heat from biomass power generation. 13. The geothermal heat exchanger according to any one of claims 1 to 12 , wherein the external heat source is LPG combustion gas. A geothermal power generation system for generating power using the geothermal heat exchanger according to any one of claims 1 to 13 .

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