JPH0355762Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a geothermal power generation plant, and in particular to a geothermal power generation plant in a total flow system suitable for converting the thermal energy of a geothermal two-phase flow into shaft power to generate electricity. Regarding power plants.

[Conventional technology]

Conventionally, the power generation system of a geothermal power plant uses a steam separator to separate the geothermal two-phase flow extracted from a production well into hot water and steam, and then feeds this steam to a steam turbine to drive the steam turbine. Therefore, as shown in FIG. 2, a total flow turbine 14 is provided between the steam separator 10 and the steam turbine 12 to reduce the amount of water discharged from the steam separator 10. The hot water introduced through the nozzle 16 is depressurized and expanded to be accelerated, converting the thermal energy of the hot water into kinetic energy of a two-phase flow, and further increasing the kinetic energy of this two-phase flow. A device that converts energy into shaft power and drives the rotating shaft 18 is known. According to the system using this total flow turbine 14,
The steam turbine 12 is rotated by high-pressure steam from the steam separator 10 and low-pressure steam from the total flow turbine 14, and is also rotated by the driving force from the rotating shaft 18, so that the steam turbine 12 is rotated by only steam. It is possible to increase the output of the plant compared to the one that drives it.

[Problem that the invention attempts to solve]

However, in the system shown in FIG. 2, the hot water supplied to the nozzle 16 is a single-phase flow, so if the thermal energy of this hot water is relatively small, it will not be possible to Even if the hot water was expanded under reduced pressure, the speed of the gas-liquid two-phase flow injected from the nozzle 16 could not be sufficiently increased, and this was not sufficient to increase the shaft power conversion efficiency of the total flow turbine 14. For this reason, there has been a problem in that the output of the total flow turbine 14 cannot be sufficiently increased when the thermal energy of the hot water is relatively small.

In order to supply the geothermal two-phase flow to the nozzle 16, a portion of the high-pressure steam from the steam-water separator 10 is supplied to the nozzle 16 to sufficiently increase the speed of the gas-liquid two-phase flow injected from the nozzle 16. It is also possible to increase the shaft power conversion efficiency of the total flow turbine 14, but in this case, even if the shaft power conversion efficiency of the total flow turbine 14 becomes high, the amount of high-pressure steam supplied to the steam turbine 12 decreases, and the steam turbine 1
Since the output of No. 2 decreases, it is not possible to increase the conversion efficiency of the shaft power as a whole.

The present invention was developed in view of the above-mentioned conventional problems, and its purpose is to convert the hot water separated from the geothermal two-phase flow into a gas-liquid two-phase flow using the thermal energy of this hot water, and to convert this into a gas-liquid two-phase flow. It is an object of the present invention to provide a geothermal power generation plant capable of converting thermal energy possessed by a gas-liquid two-phase flow into shaft power using a total flow turbine.

[Means for solving problems]

In order to achieve the above object, the present invention includes a steam-water separator that takes in geothermal two-phase flow and separates it into steam and hot water, and a steam-water separator that introduces hot water from the steam-water separator to reduce pressure and
An expansion valve that expands, an evaporator that takes in the hot water that has been depressurized and expanded by the expansion valve and converts a part of the hot water into steam, and introduces the evaporated residual hot water and steam from the evaporator and mixes it to generate heat. It has a mixer that generates a gas-liquid two-phase flow of water and steam, and a nozzle that introduces the gas-liquid two-phase flow from the mixer and converts the thermal energy of the gas-liquid two-phase flow into kinetic energy. A total flow turbine that converts the kinetic energy of the fluid to be injected into shaft power, and a steam turbine that is rotated by the shaft power of the total flow turbine and also rotated by at least steam from a steam separator, and this rotation drives a generator. and geothermal power plants, including.

[Effect]

The geothermal two-phase flow extracted from the production well is separated into steam and hot water by a steam separator, and the steam is supplied as high-pressure steam to a steam turbine, and the hot water is sent to an evaporator via an expansion valve. Supplied. When the hot water that has been depressurized and expanded by the expansion valve is supplied to the evaporator,
Expanding in the evaporator, the hot water boils and some of it evaporates. Then, the hot water and steam flowing out from the evaporator are mixed in a mixer as a gas-liquid two-phase flow, and the mixture is supplied to the nozzle of the total flow turbine. The gas-liquid two-phase flow introduced into the nozzle is expanded under reduced pressure within the nozzle and accelerated, and the thermal energy of the gas-liquid two-phase flow is converted into kinetic energy. Then, the kinetic energy of the gas-liquid two-phase flow injected from the nozzle is converted into shaft power and transmitted to the steam turbine. The steam turbine drives a generator using the shaft power transmitted from the total flow turbine and the shaft power generated by converting at least the thermal energy of the steam from the steam/water separator in the steam turbine.

[Example of idea]

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows the configuration of a preferred embodiment of the present invention. In FIG. 1, a geothermal two-phase flow taken out from a production well is supplied to a steam-water separator and separated into high-pressure steam and high-pressure/high-temperature hot water. The high pressure steam is fed to the steam turbine 12, and the hot water is fed to the pipe 2.
0, evaporator (flashure) 2 via expansion valve 22
4 is now being sent. Expansion valve 22
is designed to reduce the pressure and expand the hot water from the steam-water separator 10, and then feed it to the evaporator 24.

The evaporator 24 takes in the hot water that has been depressurized and expanded by the expansion valve 22, stores the hot water, and converts a portion of the hot water into steam before flowing out. That is, the hot water introduced into the evaporator 24 expands within the evaporator 24, the hot water boils, and a portion of the hot water evaporates. The evaporated water is sent to the mixer 26 via the pipe 24, and the residual hot water from the evaporation is sent to the mixer 26 via the pipe 28. The mixer 26 is adapted to introduce and mix steam and hot water to produce a gas-liquid two-phase flow of hot water and steam. Then, the gas-liquid two-phase flow flows through the nozzle 1 of the total flow turbine 14.
6.

The gas-liquid two-phase flow introduced into the nozzle 16 is expanded under reduced pressure within the nozzle 16, accelerated, and injected into the total flow turbine 14. At this time, the thermal energy of the gas-liquid two-phase flow is converted into the kinetic energy of the gas-liquid two-phase flow. The kinetic energy of this gas-liquid two-phase flow is converted into shaft power within the total flow turbine 14 and transmitted to the steam turbine 12 via the rotating shaft 18. On the other hand, the gas-liquid two-phase flow converted into shaft power is separated within the total flow turbine 14 and flows out, and the low pressure steam that flows out is sent to the steam turbine 12.

The steam turbine 12 converts the thermal energy of high-pressure steam from the steam separator 10 and low-pressure steam from the total flow turbine 14 into shaft power, and this shaft power and the shaft power from the rotating shaft 18 drive a generator. be done.

As described above, in this embodiment, hot water flowing out from the steam separator 10 is converted into a gas-liquid two-phase flow of hot water and steam, and this gas-liquid two-phase flow is sent to the nozzle 16. Therefore, even if the flow path of the nozzle 16 is short, the mist particle size of the gas-liquid two-phase flow can be made smaller and accelerated more easily than when a single-phase flow is introduced into the nozzle 16. The speed of the gas-liquid two-phase flow injected from the nozzle 16 can be increased. As a result, even when the thermal energy of the hot water is relatively small, it is possible to increase the energy conversion efficiency of converting the thermal energy of the two-phase flow introduced into the nozzle 16 into kinetic energy,
It is possible to increase the output of the total flow turbine 14 without causing a decrease in the output of the steam turbine 12.

[Effect of idea]

As explained above, according to the present invention, hot water separated from a geothermal two-phase flow is converted into a gas-liquid two-phase flow of steam and hot water, and this gas-liquid two-phase flow is sent to the nozzle of a total flow turbine. This makes it possible to increase the speed of the two-phase flow injected from the nozzle, increasing the energy conversion efficiency of the total flow turbine even when the thermal energy of the hot water is relatively small. This can contribute to increasing the overall output of the total flow turbine and steam turbine.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing one embodiment of the present invention;
The figure is a configuration diagram of a conventional example. 10... Steam water separator, 12... Steam turbine,
14... Total flow turbine, 16... Nozzle, 22... Expansion valve, 24... Evaporator, 26...
mixer.

Claims (1)

[Scope of utility model registration request] A steam-water separator that takes in geothermal two-phase flow and separates it into steam and hot water; an expansion valve that introduces hot water from the steam-water separator to reduce pressure and expand;
An evaporator that takes in the expanded hot water and converts a part of the hot water into steam; and an evaporator that introduces and mixes the evaporated residual hot water and steam to generate a gas-liquid two-phase flow of hot water and steam. It has a mixer that introduces a gas-liquid two-phase flow from the mixer and a nozzle that converts the thermal energy of the gas-liquid two-phase flow into kinetic energy, and converts the kinetic energy of the fluid injected from the nozzle into shaft power. A geothermal power generation system characterized by comprising: a total flow turbine that rotates by shaft power of the total flow turbine, and a steam turbine that is rotated by at least steam from a steam separator and drives a generator by this rotation. plant.