JPS62255506A - Combined type geothermal power plant - Google Patents

Abstract

PURPOSE:To improve the heat efficiency and reduce the wetness at the outlet side of a steam turbine, by overheating a high-pressure saturated steam and a hot water to be discharged from a steam separator, so as to convert the same to an overheated steam, and feeding the overheated steam to the steam turbine. CONSTITUTION:A geothermal two-phase flow blown out from the underground is inducted to a steam separator 10, and is separated into a hot water and a high-pressure saturated steam. Then, the high-pressure saturated steam is fed to an overheated high-pressure steam generator in a boiler 24, and is converted to an overheated high-pressure steam. On the other hand, the hot water is fed to an overheated low-pressure steam generator in the boiler 24 by a pump 26, and is converted to an overheated low-pressure steam. Both the overheated high-pressure steam and the overheated low-pressure steam are fed to a steam turbine 14 to drive a generator 18. Accordingly, the steam temperature at the inlet side of the steam turbine 14 is increased, thereby improving the heat efficiency. At the same time, as the steam having a reduced wetness is discharged from the outlet side of the steam turbine 14, a turbine blade may be prevented from being eroded or corroded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a combined geothermal power generation plant, and particularly to a combined geothermal power generation plant suitable for converting geothermal energy into electric power using both a steam turbine and a gas turbine. Regarding plants.

[Conventional technology]

Geothermal energy extracted from underground can take the form of natural steam or two-phase fluid containing steam and hot water. A two-stage flash geothermal power generation plant, as shown in FIG. 7, is known as a power generation plant using two-phase fluid among such geothermal energy.

In the power plant shown in FIG. 7, a geothermal two-phase flow extracted from underground is introduced into a steam separator 10 to be separated into high pressure saturated steam and hot water, and the high pressure saturated steam is passed through a mist separator 12. The high-pressure steam is converted into high-pressure steam and sent to a steam turbine 14, while the hot water is sent to a flasher (evaporator) 16.
The low-pressure steam is converted into low-pressure steam, and the low-pressure steam is sent to the steam turbine 14. steam turbine 1
4 introduces low pressure steam and high pressure steam to drive the generator 18. Note that the steam discharged from the steam turbine 14 is supplied to the condenser 20. The steam fed to the condenser 20 is converted into water and circulated between the condenser 20 and the cooling tower 22. Further, a part of the hot water fed to the flasher 16 is discharged as reduced water. According to the plant with the above configuration,
Geothermal energy can be effectively converted into electricity.

[Problem that the invention seeks to solve]

However, in the geothermal power plant shown in FIG. 7, both high-pressure steam and low-pressure steam supplied to the steam turbine 14 are saturated steam, resulting in poor thermal efficiency and high humidity on the exit side of the steam turbine 14. However, there was a problem that the turbine blades were easily eroded or corroded.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a combined geothermal power plant that can improve thermal efficiency and reduce humidity on the steam turbine outlet side.

Means for Solving Problem C] To achieve the above object, the present invention provides a steam separator that separates a geothermal two-phase flow into hot water and high-pressure saturated steam, and a high-pressure saturated steam from the steam separator. a heating high-pressure steam generator that superheats saturated steam and converts it into superheated high-pressure steam; a superheated low-pressure steam generator that converts hot water from a steam-water separator into superheated low-pressure steam; and the superheated high-pressure steam and superheated low-pressure steam. This is a combined geothermal power plant with a steam turbine that drives a generator.

[Effect]

Geothermal two-phase flow erupted from underground is introduced into a steam-water separator to separate it into hot water and high-pressure saturated steam, and the high-pressure saturated steam is sent to a superheated high-pressure steam generator to be converted into superheated high-pressure steam. On the other hand, hot water is sent to a superheated low pressure steam generator and converted into superheated low pressure steam. These heated high-pressure steam and superheated low-pressure steam are then respectively sent to a steam turbine to drive a generator.

[Embodiments of the invention]

EMBODIMENT OF THE INVENTION Below, one embodiment 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 this embodiment, as shown in FIG. 1, a boiler 24 is inserted between a mist separator 12 and a steam turbine 14, and a pump 26 and a boiler 24 are inserted between a steam separator 10 and a flasher 16. Since the other configurations are the same as those shown in FIG. 7, the same components are given the same reference numerals and their explanation will be omitted.

The boiler 24 is supplied with high-temperature waste gas from the drive of the gas turbine 28, and when this high-temperature exhaust gas is discharged from the boiler 24 as low-temperature exhaust gas, high-pressure steam is superheated and output as superheated high-pressure steam. Ru. moreover,
The hot water discharged by the pump 26 is superheated and output as high temperature hot water. That is, the boiler 24 constitutes a part of a superheated high pressure steam generator and a superheated low pressure steam generator. The superheated high pressure steam is then transferred to the steam turbine 1.
The high-temperature hot water is converted into low-pressure steam by a flasher 16 and is then fed to the low-pressure side of the steam turbine 14. In this way, in this embodiment, superheated high-pressure steam and low-pressure steam are introduced into the steam turbine 14, so the temperature of the steam on the artificial side of the steam turbine 14 becomes higher, and the thermal efficiency is improved compared to the conventional one. can be achieved. Furthermore, since steam with significantly reduced humidity is discharged to the outlet side of the steam turbine 14, erosion or corrosion of the turbine blades of the steam turbine 14 can be suppressed.

Note that the gas turbine 28 drives the generator 34 using thermal energy generated when a mixture of compressed air and fuel supplied from the air compressor 30 is combusted in the combustor 32.

FIG. 2 shows the configuration of another embodiment of the invention.

In this embodiment, a rotary separation type two-phase flow turbine 36 is used in place of the flasher 16 shown in FIG. 1, and the other configurations are the same as those in FIG. are given the same reference numerals and their explanation will be omitted.

In this embodiment, when high-temperature hot water discharged from the boiler 24 is converted into low-pressure steam, the flasher 16 in FIG.
However, with the two-phase flow turbine 36, the kinetic energy loss due to pressure reduction when converting high-temperature hot water into low-pressure steam can be recovered. It is possible to improve thermal efficiency.

Furthermore, according to this embodiment, similar to the plant shown in FIG.
As shown in Figure 3, the temperature of high-temperature hot water is given by characteristic A.
In addition, the temperature of the high-pressure steam can be made to have the characteristic shown by characteristic B, and the thermal efficiency can be improved and the humidity on the exit side of the steam turbine 14 can be significantly reduced compared to conventional ones. can. Note that characteristic C indicates a process in which high-temperature gas introduced into the boiler 24 is discharged as low-temperature exhaust gas.

FIG. 4 shows the configuration of another embodiment of the present invention.

In this embodiment, as shown in FIG.
The hot water discharged from the flasher 16 is guided to the flasher 16, the low pressure steam discharged from the flasher 16 is sent to the boiler 24 via the mist separator 38, and the heated low pressure steam generated from the boiler 24 is sent to the boiler 14. The other configuration is the same as that in Figure 1, so
Identical components are given the same reference numerals and their descriptions will be omitted.

In this embodiment, hot water is converted into low-pressure steam by the flasher 16, and the low-pressure steam is supplied to the boiler 24 via the mist separator 38, so the temperature of the geothermal two-phase flow is high, and the flasher 16 converts the hot water into low-pressure steam. This is suitable when the temperature of the generated low-pressure steam can be set high enough to prevent sulfuric acid corrosion in the boiler 24. In this case, as shown in FIG. 6, the low pressure steam can be superheated to the temperature of superheated low pressure steam as shown by characteristic A. Furthermore, characteristic B
, C have characteristics similar to those in FIG.

Furthermore, in this embodiment as well, the temperatures of the low-pressure steam and high-pressure steam introduced into the steam turbine 14 can be increased, as in the previous embodiments, thereby improving thermal efficiency and significantly reducing the humidity on the output side of the turbine 14. can be done.

FIG. 5 shows the configuration of yet another embodiment of the present invention.

In this embodiment, a rotary separation type two-phase flow turbine 36 is used in place of the flasher 16 shown in FIG. 4, and the other configurations are the same as those in FIG. are given the same reference numerals and their explanation will be omitted.

In this embodiment, like the one in FIG. 2, a two-phase flow turbine 36 is used in place of the flasher 16, so that the kinetic energy lost when converting hot water into low-pressure steam can be recovered. , the thermal efficiency can be improved more than that shown in FIG.

Further, as shown in FIG. 8, the gas turbine combined power generation plant includes a steam turbine 14, a generator 18, a condenser 20, a cooling tower 22, a boiler 24, a pump 26, a gas turbine 28. Air compressor 30, combustor 32
, a generator 34 is known, but in this power generation plant system, the exhaust gas of the gas turbine 28 contains sulfur, so in order to avoid sulfuric acid corrosion, the inlet temperature of the boiler 24 is lowered. It is set at around 130 to 140"C. Therefore, in the power generation plant system shown in Figure 8, preheating is required to raise the temperature of the condensate introduced into the boiler 24, as shown in Figure 9. In addition, it was difficult to maintain the temperature of the exhaust gas discharged from the boiler 24 at 150° C. or lower.

On the other hand, in each of the above embodiments according to the present invention,
As shown in FIGS. 3 and 6, there is no need to preheat the steam, and the high temperature exhaust gas (
500"C) to superheat high-pressure steam,
Since hot water is used to superheat the exhaust gas and the exhaust gas is lowered to around 150°C and then discharged as low-temperature exhaust gas, it is possible to improve the heat absorption efficiency compared to that of a gas turbine combined power generation plant.

〔Effect of the invention〕

As explained above, according to the present invention, high-pressure saturated steam and hot water discharged from a steam-water separator are respectively superheated and converted into superheated high-pressure steam and superheated low-pressure steam, and these steams are sent to a steam turbine. This increases the temperature at the inlet side of the steam turbine and reduces the humidity at the outlet side of the steam turbine, which not only improves the thermal efficiency of the steam turbine drive, but also contributes to improving the durability of the steam turbine. You can get excellent results.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the first embodiment of the present invention, Fig. 2 is a block diagram showing the second embodiment of the present invention, and Fig. 3 is the amount of heat and temperature of the plant shown in Figs. 1 and 2. Fig. 4 is a diagram showing the configuration of the third embodiment of the present invention, Fig. 5 is a block diagram showing the fourth embodiment of the invention, and Fig. 6 is a diagram showing the plant shown in Fig. 4. A diagram showing the relationship between the amount of heat and temperature, Figure 7 is a configuration diagram of a conventional geothermal power generation plant, Figure 8 is a configuration diagram of a conventional gas turbine combined power generation plant, and Figure 9 is shown in Figure 8. It is a diagram showing the relationship between the amount of heat and temperature of a plant. 1o... Steam water separator, 12.38... Mist separator, 14... Steam turbine, 16... Flasher, 18.34... Generator, 24... Boiler, 28...
...Gas turbine, 36...Rotation separation type two-phase flow turbine.

Claims (5)

[Claims] (1) A steam-water separator that separates geothermal two-phase flow into hot water and high-pressure saturated steam; and a superheated high-pressure steam generator that heats the high-pressure saturated steam from the steam-water separator and converts it into superheated high-pressure steam; It is characterized by having a superheated low pressure steam generator that converts hot water from a steam water separator into superheated low pressure steam, and a steam turbine that introduces the superheated high pressure steam and superheated low pressure steam to drive a generator. A combined geothermal power plant. (2) The superheated low-pressure steam generator includes a boiler that superheats hot water and an evaporator that converts the hot water superheated by the boiler into superheated low-pressure steam. The combined geothermal power plant described in Section 1. (3) A patent characterized in that the superheated low-pressure steam generator includes a boiler that superheats hot water and a rotary separation type two-phase flow turbine that converts the hot water superheated by the boiler into superheated low-pressure steam. A combined geothermal power plant according to claim 1. (4) The superheated low-pressure steam generator includes an evaporator that converts hot water into low-pressure steam, and a boiler that superheats the low-pressure steam from the evaporator. combined geothermal power plant. (5) The heated low-pressure steam generator includes a rotary separation type two-phase flow turbine that converts hot water into low-pressure steam, and a boiler that heats the low-pressure steam from the turbine. A combined geothermal power plant according to scope 1.