KR101216112B1 - Apparatus of low-temperature geothermal power generation and method thereof - Google Patents

Abstract

The low temperature geothermal power generation apparatus of the present invention includes a superheater 20, a post pressure pump 40, and a preheater 60 for geothermal power generation using geothermal water of 100 ° C. or less. By driving the preheater 60 by using the residual heat of geothermal water from the vaporizer 4, the temperature and enthalpy of the secondary fluid are raised to some extent to increase the efficiency of the vaporizer 4, and the superheater 20 By raising the temperature of the secondary fluid vaporized by), the pressure is consequently increased, and the pressure of the secondary fluid flowing into the turbine 6 by the after-pressure pump 40 is increased while the vaporizer 4 and the superheater 20 are increased. By reducing the pressure of), the efficiency of the vaporizer 4 can be increased and the flow rate of the superheater 20 can be maintained, so that even if a relatively low temperature geothermal water is used, efficient power generation can be performed.

Description

Low temperature geothermal power generation apparatus and method {APPARATUS OF LOW-TEMPERATURE GEOTHERMAL POWER GENERATION AND METHOD THEREOF}

The present invention relates to low-temperature geothermal power generation, and more particularly, by applying a preheater, a superheater and a post-pressure pump, by using the residual heat of geothermal water from the vaporizer to drive the preheater to reduce the temperature and enthalpy of the secondary fluid. To increase the efficiency of the vaporizer by increasing the temperature of the vaporized secondary fluid by installing a superheater at the rear end of the vaporizer, and to increase the pressure by installing a back pressure pump at the rear of the superheater. The present invention relates to a low-temperature geothermal power generation apparatus and method capable of increasing the pressure and reducing the pressure of the vaporizer and the superheater, thereby improving the efficiency of the vaporizer and maintaining the flow rate of the superheater.

As is well known, geothermal power generation is the generation of heat in the form of steam or hydrothermal heat in the underground hot layer, where geothermal heat is hot water (hot spring) several kilometers deep from the shallow surface of the earth. And rocks (magma) are the energy that they have. In general, the geothermal temperature in the natural state increases the average 3 ~ 4 ℃ the deeper 100m underground. Depending on the area and the way it is developed, wells can be dug a few hundred meters to several kilometers deep.

When hot steam is obtained from the well, it is led to a steam turbine and the turbine is rotated at high speed to produce power by a generator directly connected to it. If the steam spouted from the well contains little moisture, it can be sent to the turbine as it is.However, if spouted as hot water, the heat is sent to a heat exchanger to evaporate the water and sent to the turbine. The lower liquid can also be evaporated and sent to the turbine.

This geothermal power generation, in principle, does not require fuel, so clean energy is free from environmental pollution caused by the combustion of fuel. However, a small amount of hydrogen sulfide is contained in the non-condensable gas ejected from the geothermal point. At present, there is no problem because the concentration is lower than the environmental standard, but if it is ejected in large quantities in the future, a desulfurization device will be required. In addition, although a small amount of arsenic is contained in the hot water, all of it is reduced back to the basement after power generation. However, if economical dearsenic technology is established, this hot water can also be used as a valuable low-temperature heat energy source.

In addition, most of geothermal power costs are due to the construction cost of geothermal power plants and the excavation cost of geothermal wells, which also depend on the quality of geothermal resources and the way of power generation. It is a strength and has the feature of a small, decentralized local energy resource.

In this way, since geothermal power is using the energy of the earth itself, the potential is almost infinite depending on the depth of excavation. Thus, heat-producing areas are widespread throughout the world, increasing in number, and increasing in the future.

FIG. 1 shows the configuration of a typical geothermal power generation apparatus that is performed in a volcanic zone that can secure geothermal water of 120 ° C. or higher at a relatively high temperature. As shown in FIG. 1, the geothermal power generation device is constructed by supplying geothermal water to a vaporizer 4 through a supply pump 2, that is, by evaporating a secondary fluid having a low boiling point through a heat exchanger corresponding to a boiler. By driving 6), the geothermal water passed through the vaporizer 4 is reduced. After the turbine 6 generates power in the generator 8 and drives the turbine 6, the secondary fluid vapor is condensed into water through the condenser 10 to which the cooling water is supplied, and then the circulation pump 12 is Is supplied again to the vaporizer 4 as a secondary fluid.

The conventional geothermal power generation as described above is a structure that drives the turbine by vaporizing the secondary fluid having a low boiling point in the vaporizer by supplying geothermal water, such a simple structure is very advantageous in terms of economic efficiency in the situation where abundant geothermal water is supplied above 100 ℃ However, even if heat exchange is carried out with the vaporizer 4 which is designed to be highly efficient, since the temperature of the geothermal water discharged after use is considerably higher than the secondary fluid in which pluralization is performed, the heat exchanger using one vaporizer 4 has been conventionally used. As it is difficult to expect high heat transfer efficiency from geothermal water to secondary fluid, the conventional geothermal power generator shown in FIG. There is a problem that it is difficult to expect.

However, in Korea, there is no high temperature geothermal energy related to volcanic activity, but in some regions, it is possible to secure abundant geothermal water of about 90 ℃, so it is a wasteful condition to give up geothermal power in these regions. Since the existing geothermal power generation method is insufficient economic feasibility, there is an urgent need for advanced technology to solve this problem.

The present invention has been made to meet the above situation, the object of the present invention is to provide a low-temperature geothermal power generation apparatus and method that can perform an effective geothermal power generation using a relatively low temperature geothermal water.

In order to achieve the above object, a low-temperature geothermal power generation apparatus according to an aspect of the present invention includes a vaporizer for vaporizing secondary fluid into secondary fluid vapor by geothermal water, and the secondary fluid vapor vaporized through the vaporizer. A superheater for increasing the steam pressure by raising the temperature to a temperature; a post pressure pump for further increasing the steam pressure raised by the superheater; a turbine driven by the steam pressure further increased by the postpressure pump; And a condenser for condensing the secondary fluid vapor after driving the turbine with water, and condensed water from the condenser to a predetermined temperature to be supplied as the secondary fluid to the vaporizer from the vaporizer. It includes a preheater supplied with the residual heat of geothermal water.

The steam pressure raised by the after pressure pump is higher than the critical pressure, and the temperature of the secondary fluid steam raised by the superheater is preferably 80 ° C. or higher.

In the present invention, geothermal water having a temperature of 100 ° C. or lower is used.

According to another aspect of the present invention, a low-temperature geothermal power generation method includes supplying geothermal water of 100 ° C. or lower to a vaporizer to vaporize a secondary fluid to secondary fluid vapor, and superheating the secondary fluid vapor vaporized through the vaporizer. Increasing the steam pressure by increasing the temperature to a predetermined temperature in the step of increasing the steam pressure increased by the superheater by a after-pressure pump, and driving the turbine at a further elevated steam pressure by the after-pressure pump. Operating the turbine, condensing the secondary fluid vapor from the condenser into water in the condenser, and the remaining heat of the geothermal water from the vaporizer is supplied to a preheater to bring the condensed water from the condenser to a predetermined temperature. Raising the feed to the vaporizer as the secondary fluid.

According to an embodiment of the present invention, by driving the preheater using the residual heat of the geothermal water from the vaporizer, the temperature and enthalpy of the secondary fluid are raised to some extent to increase the efficiency of the vaporizer, and the vaporized by the superheater. Increasing the temperature of the secondary fluid increases the pressure and, consequently, increases the pressure of the secondary fluid introduced into the turbine by the after-pressure pump and at the same time reduces the pressure of the vaporizer and the superheater, thereby increasing the efficiency of the vaporizer and maintaining the flow rate of the superheater. Therefore, even when using a relatively low-temperature geothermal water has an effect that can perform an effective power generation.

1 is a schematic view showing the configuration of a typical geothermal power generation apparatus that is carried out in a volcanic zone that can secure geothermal water of 120 ° C. or higher at a relatively high temperature.
2 is a schematic view showing the configuration of a low-temperature geothermal power generation device according to the present invention,
3 is a graph showing the relationship between gas pressure and turbine efficiency,
4 is a process chart showing a low-temperature geothermal power generation method according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in the following description of the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof is omitted. In the drawings, the same components as in the related art are denoted by the same reference numerals, and detailed descriptions thereof are omitted for convenience of description.

2 shows a configuration of a low temperature geothermal power generation device according to the present invention. As shown, the low temperature geothermal power generation apparatus of the present invention is a superheater 20, a post pressure pump 40 and a preheater for geothermal power generation using geothermal water of 100 ℃ or less It includes 60, in particular, the geothermal water is directly supplied to the vaporizer 4 through the circulation pump 12 is the same as the existing, geothermal water discharged after heat-exchanging the geothermal water supplied to the vaporizer 4 By applying the residual heat of the preheater 60, the second heat exchange process of raising the secondary fluid to a certain temperature is applied. The preheater 60 raises the temperature and enthalpy of the secondary fluid to some extent to increase the efficiency of the vaporizer 4.

By the way, the turbine 6 for power generation has a correlation as can be seen from the graph of FIG. 3 between the pressure of the gas or steam flowing into the turbine 6 and the turbine efficiency. In other words, when the pressure of the gas flowing into the turbine 6 exceeds a certain threshold, the efficiency is improved in proportion to the pressure, and below the threshold, the efficiency is drastically reduced. Therefore, maintaining the pressure above the threshold is an important condition, it is difficult to maintain the critical pressure required for economic development with relatively low temperature geothermal water of less than 100 ℃.

Accordingly, in the low temperature geothermal power generation apparatus of the present invention, the superheater 20 is connected to a steam pipe connecting the vaporizer 4 and the turbine 6 to raise the temperature of the steam flowing into the turbine 6 and consequently increase the pressure. The pressure of the vaporizer 4 is reduced, the pressure of the secondary fluid flowing into the turbine 6 is increased, and the pressure of the vaporizer 4 and the superheater 20 is reduced. In order to increase the efficiency and maintain the flow rate of the superheater 20, a pressure pump 40 was installed at the rear end of the superheater 20 to maintain a pressure higher than the critical pressure on the steam flowing into the turbine 6.

The superheater 20 may increase the pressure by giving a temperature rise to the already vaporized secondary fluid. In general, the temperature after the vaporization of the secondary fluid used for geothermal power generation is about 60 ℃ degree, the superheater 20 can raise it to more than 80 ℃. Vaporized secondary fluids have a low specific heat and do not require much energy consumption in this process.

In addition, the back pressure pump 40 increases the pressure applied to the turbine 6 and at the same time reduces the pressure of the vaporizer 4, thereby further increasing the efficiency of the vaporizer 4.

On the other hand, since the superheater 20 and the after-pressure pump 40 is electrically operated, if the turbine efficiency according to the pressure is constant, its role does not have meaning according to the law of energy conservation, but as can be seen from FIG. If the pressure of the fluid is below the critical pressure, it is very important considering the efficiency of the turbine, that is, economical, even if it consumes a certain amount of energy, the present invention uses relatively low geothermal water. In the low temperature geothermal power generator of, it is evident that the application of the superheater 20 and the after pressure pump 40 is considerably advantageous in terms of overall power generation efficiency compared to the energy consumed for its operation.
That is, the geothermal power generation apparatus of the present invention, as can be seen through Figure 2, after the secondary fluid steam driving the turbine 6 is condensed into water through the condenser 10, the preheater through the circulation pump 12 It is supplied to 60, and is supplied again to the vaporizer | carburetor 4 again.
As such, as the condensed water is raised to a predetermined temperature through the preheater 60 and supplied to the vaporizer 4, an effective power generation can be performed even when using low temperature water having a relatively low temperature, and the vaporizer through the preheater 60. The condensed water supplied to (4) is reduced again through the preheater (60).

The low-temperature geothermal power generation device of the present invention configured as described above can increase the efficiency of the vaporizer by preheating the secondary fluid by the preheater 60 using the residual heat of geothermal water, the superheater 40 and the after-pressure pump 60 By increasing the pressure of the secondary fluid flowing into the turbine and reducing the pressure of the carburetor and superheater, it is possible to increase the efficiency of the carburetor and maintain the flow rate of the superheater. Can be done.

The geothermal power generation method according to the low temperature geothermal power generation apparatus according to the present invention configured as described above will be described with reference to FIG. 4.

First, geothermal water of 100 ° C. or less is supplied to the vaporizer 4 to vaporize the secondary fluid to secondary fluid steam (S10).

Subsequently, the secondary fluid vapor vaporized through the vaporizer 4 is raised to a temperature of about 80 ° C. or more in the superheater 20 to increase the vapor pressure (S20), and the vapor pressure increased by the superheater 20 is then back pressured. Further increase through the pump 40 (S30).

Next, the generator 8 is operated by driving the turbine 6 at a further elevated steam pressure through the after pressure pump 40 (S40).

After the turbine 6 is driven, the secondary fluid steam is condensed with water through the condenser 10 (S50), and the remaining heat of geothermal water from the vaporizer 4 is supplied to the preheater 60 to condense the condenser 10. The condensed water from) is raised to a predetermined temperature and supplied to the vaporizer 4 as a secondary fluid (S60). Accordingly, the present invention can perform an effective power generation using geothermal water of a relatively low temperature, this technology can be applied to the waste heat recovery power generation from incinerators, gas turbines and the like.

Although the low-temperature geothermal power generation apparatus and method of the present invention have been described as specific embodiments in the foregoing detailed description, it should be interpreted that the technical elements disclosed in the present specification have the widest scope, and those skilled in the art will appreciate the materials, sizes, and the like of each component. It can be easily changed depending on the application. It is also possible to adopt a structure not shown by combining / substituting the disclosed embodiments, which again does not depart from the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be readily made without departing from the spirit and scope of the invention as defined by the appended claims.

2: supply pump 4: vaporizer
6: turbine 8: generator
10: condenser 12: circulation pump
20: superheater 40: after-pressure pump
60: preheater

Claims (5)

A vaporizer which vaporizes the secondary fluid into secondary fluid steam by geothermal water,
A superheater for raising the vapor pressure by raising the secondary fluid vapor vaporized through the vaporizer to a predetermined temperature;
A after-pressure pump for further raising the vapor pressure raised by the superheater;
A turbine driven at a higher steam pressure by the after pressure pump;
A generator operated by driving of the turbine,
A condenser for condensing the secondary fluid vapor after driving the turbine with water;
And a preheater supplied with residual heat of geothermal water from the vaporizer so that the condensed water from the condenser is raised to a predetermined temperature and supplied to the vaporizer as the secondary fluid.
Low temperature geothermal power generation device.
The method of claim 1,
The steam pressure further increased by the after pressure pump is equal to or greater than the critical pressure.
Low temperature geothermal power generation device.
The method of claim 1,
The temperature of the secondary fluid vapor raised by the superheater is 80 ℃ or more
Low temperature geothermal power generation device.
The method according to any one of claims 1 to 3,
The geothermal water is less than 100 ℃
Low temperature geothermal power generation device.
Supplying geothermal water to the vaporizer to vaporize the secondary fluid to the secondary fluid vapor;
Raising the vapor pressure by raising the secondary fluid vapor vaporized through the vaporizer to a predetermined temperature through a superheater;
Further raising the vapor pressure raised by the superheater through a after pressure pump;
Operating a generator by driving a turbine at a higher steam pressure by the after pressure pump;
Condensing the secondary fluid vapor after driving the turbine with water in a condenser;
Residual heat of geothermal water from the vaporizer is supplied to the preheater to raise the condensed water from the condenser to a predetermined temperature and supplied to the vaporizer as the secondary fluid
Low temperature geothermal power generation method.

Images