JPS6237646A - Taking geothermal energy out of earth through heat siphon - Google Patents

Abstract

PURPOSE:To take geothermal energy out of earth efficiently and contrive long service life of the heat siphon by a method wherein water, containing acid- neutralizing agent, is poured into the hole of boring and the heat receiving section of the heat siphon is provided so as to be located in poured water. CONSTITUTION:The boring hole 10 is formed in a high-temperature rock body 7. Next, a boring gun is hung down into the tip end of the boring hole 10 to pour the water 12, containing acid-neutralizing agent, into the tip end of the boring hole 10. In this case,the amount of water is determined to a degree of dipping the heat receiving section of heat siphon sufficiently while the amount of acid-neutralizing agent is determined properly in accordance with the amount of acidic substance such as SO2 or the like which is generated out of the high- temperature rock body 7. Subsequently, the finned heat siphon 13 is installed. In this case, the heat receiving section 13a of the heat siphon 13 is installed so as to be dipped into the poured water 12 while the heat dissipating section 13b thereof is installed at a requested position on the earth.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method of highly efficiently extracting geothermal energy possessed by a high-temperature rock body that does not generate hydrothermal water using a heat siphon.

"Prior Art" Prior to the present application, the inventor provided a heat siphon that made it possible to extract geothermal energy even from high-temperature rock bodies that do not generate hydrothermal water (Utility Application No. 188247-1982).
. This heat siphon is composed of a heat siphon 'ltl and a protective bone 2, as shown in FIG.

The heat siphon tube 1 is composed of a large number of bone gauges connected (welded) in series, and the tube body (heat receiving part) 3a at the lower end and the tube body (heat dissipation III) 3b at the upper end are The tip is closed, and fins for receiving and dissipating heat are formed on the outer periphery. The interior of the heat siphon tube 1 formed in this manner is filled with a working fluid 4.

The protective tube 2 is made up of a tube body 3 of a larger diameter that constitutes the heat siphon tube 1, and a tube body 5 with a larger diameter. The tube bodies 5b #52 are welded to the tube bodies 3b and 3aK, respectively.

The space between the heat siphon tube 1 and the protection tube 2 is kept in a reduced pressure vacuum state, forming a vacuum heat insulating layer 6.

In order to apply the heat siphon device having the above configuration to, for example, heat extraction from a high-temperature rock body, first, boring is performed in the rock mass 7, and the tube bodies 3 are connected one after another by welding the tube bodies 3aK at the lower end. There is also a pipe body 5 on the outside.
Welded ... and descended into the high humidity coalescence. and,
When the heat receiving portion 11ffi3a at the lower end reaches the target location, the tube bodies 3b and 5b at the upper end are welded to make the inside airtight. Next, a vacuum pump is connected to the upper end of the tube body 3b to create a vacuum inside the heat siphon tube 1, and then a working fluid is injected into the vacuumed inside of the heat siphon tube 1 to fill the inside with only the working fluid. . moreover,
A vacuum pump is connected to the pipe body 5b at the upper end of the haze protection pipe 2, and the
92 and the heat siphon bone 1'fjr: A vacuum state is created and the space is sealed with plug stop pulp 8 or the like to form a vacuum insulation/16. Note that the reference numeral 9 in the figure indicates a plug stop valve provided in the tube body 3b.

According to the above configuration, heat is extracted from the working fluid 41C sealed in the heat siphon tube 11, so heat can be easily extracted from a high-temperature rock body without hot water. Since there is no need to return the recovered hot water, boring is only required once, reducing initial costs.

"Problems to be Solved by the Invention" The inventor of the present invention has investigated a method for extracting geothermal energy from a high-temperature rock body using a heat siphon having the above configuration, and found that it is possible to extract geothermal energy more efficiently, and that the heat siphon We have now established a method that can extend the lifespan of.

"Means for Solving the Problem" The method for extracting geothermal energy using a heat siphon according to the present invention involves forming a large number of small holes or cracks in the inner wall portion of the tip of a borehole in order to increase heat release from a high-temperature rock body. At the same time, in order to improve the efficiency of heat transfer from the high-temperature rock body to the heat receiving part of the heat siphon, water is injected into the tip of the borehole, and the heat receiving part of the heat siphon is generated from the high-temperature rock body, such as 801. This method is characterized in that a Km neutralizer is added in advance to the injection water to prevent it from being deteriorated by the acid substance.

"Function" According to the above method, the amount of heat released from the high-temperature rock body can be increased by increasing the surface area of the inner wall of the coalescence due to the formation of small holes or cracks, and this heat can be absorbed by injected water to reduce heat loss. The 80. As a result, geothermal energy can be extracted with high yield, and the life of the heat siphon can also be extended.

Next, this invention will be explained in more detail with reference to Examples.

"Example" In carrying out the present invention, a borehole 10 is first formed in a high-temperature rock body 7 as shown in FIG.
(rating gun) and lower the
As shown in FIG. 2, a large number of small holes or cracks 11 are formed in the inner wall portion of the tip of the borehole 10.

The perforation gun used at this time consists of a thick walled tube with many small holes drilled around its outer periphery and filled with explosives.
It is a device that can create many small holes or cracks in the surrounding area by detonating this km. In this way, a large number of small holes or cracks 1 are formed in the inner wall portion at the tip of the borehole 10.
1... is formed, as shown in Figure 1 (C1), water 12 containing an acid neutralizer is injected into the 1° tip of this borehole. In addition, the amount of acid neutralizing agent is determined appropriately depending on the layer of acidic substances such as SOl generated from the high-temperature rock body 7.After the injection of water 12 is completed, as shown in FIG. (d
As shown in FIG. 1, a heat siphon 13 with fins is installed in the borehole 10.

In this installation, the heat receiving part 13a is immersed in the injection water 12, and the heat radiating part 13b is installed at a desired position on the ground surface. It is preferable that the heat siphon 13 is the heat siphon formed with the previously proposed vacuum heat insulating layer, but it may also be one in which a heat insulating material 14 is simply wrapped around the heat siphon 13 as shown in the figure.

According to the above method, the heat of the high-temperature rock body 7 is transferred to the water 12 through a large contact area through the small holes or cracks,
The heat is supplied to the heat receiving section 13a of the heat siphon 13 with very little heat loss. Therefore, by bringing cold air, cold water, etc. into contact with the heat dissipation part 13b of the heat siphon 13, heat can be extracted very efficiently (several hundred times that of the conventional method).
becomes possible. Also, at this time, there is enough light in the water 12 to neutralize acid substances such as SOl generated from the high-temperature rock body 7.
Since the acid neutralizer is added, heat siphon 1
Al” minilam, which is commonly used for 3’.

Even when made of materials such as copper, iron, and stainless steel, the heat siphon 13 will not deteriorate, and the lifespan 6j of the heat siphon 13 can be extended.

Note that it is desirable to use a neutralizing agent such as NaU)J as the acid neutralizer to adjust the pH of the water after injection to about 11 to treat the silica eluted into the water 12. In this way, the silica content in the water 12 changes to sodium silicate as shown in the following formula, becomes stable in the water 12, and does not adhere to the heat receiving N 15a of the heat siphon 13 as scale. In addition, water 12 is heated by the heat of the plaster 7.
If the silica is concentrated, blow it appropriately and remove the silica IA.
It is important to prevent the temperature from rising.

HISIOI + 2Na (JH→Na, 8+U, +2
H.

"Effects of the Invention" As explained above, according to the method of the present invention, it is possible to increase the heat release period of high-temperature rock bodies by increasing the surface area of coalescence and distal portions due to the formation of small holes or cracks, and this can be transported to the heat-receiving part of the heat siphon with the heat loss reduced by injected water, and the produced additive can neutralize acid substances such as SOl generated from high-temperature rock bodies. As a result, it is possible to extract geothermal energy with high yield, and it is also possible to improve the hemorrhoid life of the heat siphon.

[Brief explanation of the drawing]

Figures 1 (al to d) are explanatory diagrams showing one embodiment of the method of the present invention, and Figure 2 is a block diagram to explain an example of the conventional method.7... ...High temperature rock body, 10...Borehole, 11...Small hole or crack, 12...
・Water containing acid neutralizer. 13...Heat siphon, 13a...Mountain/heat receiving part, 13b...Heat radiation part.

Claims (1)

[Claims] A heat siphon is used to extract the geothermal energy possessed by a high-temperature rock body that does not generate hydrothermal water.In the method of extracting geothermal energy using a heat siphon, a small hole or crack is drilled into the inner wall of the tip of a borehole made in a high-temperature rock body using a drilling gun. After that, a predetermined amount of water containing an acid neutralizer is injected into this borehole, and a heat siphon is installed in this borehole so that its heat receiving part is located in the injected water to extract heat. A method for extracting geothermal energy using a heat siphon, which is characterized by performing the following.