TW201721019A - Device and method of heat retrieval under geothermal well in which hot water is caused to accelerate and circulate around an underground terminal of a heat retrieval tube - Google Patents

Abstract

A device of heat retrieval under geothermal well comprises a heat retrieval tube, wherein the heat retrieval tube has an underground terminal that is mounted with a vortex flow generation unit for generating an outward vortex effect in the underground terminal of the heat retrieval tube to induce accelerated circulation of hot water around the underground terminal of the heat retrieval tube. A method of heat retrieval under geothermal well comprises the following steps: providing a heat retrieval tube, which has an underground terminal and a surface terminal; and generating an outward vortex effect at the underground terminal of the heat retrieval tube to cause accelerated circulation of hot water around the underground terminal of the heat retrieval tube.

Description

Geothermal downhole heat taking device and method

The invention relates to a heat extraction device and a method, in particular to a geothermal underground heat extraction device and method.

Geothermal heat comes from the interior of the Earth. The heat emitted by the Earth's core is transmitted to the Earth's crust through the high-temperature magma of the Earth's name. This heat energy is called Geothermal Energy. The easiest and most cost-effective way to apply geothermal energy is to take these heat sources directly and extract their energy. The utilization of geothermal energy can be divided into two categories: direct utilization and geothermal power generation.

The direct use of geothermal energy, for example, can use hot springs as bathing and medical treatment, or use underground hot water as a temperature regulation for crop greenhouses, aquaculture and dried grains.

According to the current technical literature on the use of geothermal power generation in Taiwan, according to the development of countries and regions in the world over the past two decades, the design of geothermal power plants is distinguished by the temperature of geothermal fluids. The temperature and water vapor state of the geothermal heat source Designed for power generation facilities, there are generally technologies such as dry steam power generation, flash steam power generation, and dual-cycle power generation.

As shown in FIG. 1 , it is a schematic structural diagram of a conventional two-cycle geothermal generating set. The so-called double-cycle power generation is a geothermal fluid (hot water or steam) obtained by using the geothermal "Production Well" as a heat source for heating a working fluid having a very low boiling point. It is also necessary to input hot water of a slightly high temperature (about 130 degrees Celsius or more) from the ground to the heat exchange evaporator 90 to heat the working fluid, vaporize the working fluid, and then guide the vaporized working fluid to the turbine 91 via the pipeline. To drive the generator 92 to generate electricity, and to push the working fluid of the turbine 91 to be discharged to the recharge Inject wells or do other reuse. Because this type of power generation uses dual fluids and uses two sets of circulating fluids, it is called "double cycle" power generation.

The production well will provide an appropriate amount of geothermal fluid, and whether the geothermal fluid is geothermal water or steam, it will be directed to an evaporator 90. Inside the evaporator 90, there is a working fluid that actually pushes the turbine to generate electricity. As mentioned earlier, this working fluid has a lower temperature boiling point, so when we introduce a geothermal fluid of about 100 to 150 degrees Celsius, the working fluid will transform into a high pressure gaseous form in the evaporator 90. This high pressure gaseous working fluid will be directed to a Turbine 91 to propel the vanes to drive the generator 92.

These gaseous working fluids are then recovered by a Condenser 93, causing the working fluid to phase again into a liquid state. Finally, this liquid working fluid is brought back to the evaporator 90 by the Fluid Circulation Pump 94 for reuse.

Also, notice the path of the geothermal fluid. It is premised that the geothermal fluid in the dual-cycle power generation system is not used to directly drive the turbine generator, but is used to heat the low-boiling working fluid. Therefore, in Fig. 1, after the geothermal fluid is exothermic through the evaporator 90, these low-temperature geothermal fluids are introduced into the re-injection Well and reintroduced into the ground to restore the groundwater resources. This supplemental geothermal fluid cycle is known as the "Enhanced Geothermal System" (EGS).

Because of the deep geothermal heat, it is difficult to grasp the flow direction and source replenishment of groundwater resources. Generally speaking, the geothermal fluid after power generation is re-introduced into the ground to replenish groundwater resources and ensure the removal of geothermal heat.

As shown in FIG. 2, it is a schematic structural diagram of a conventional flash-type geothermal power generation system. The so-called flash steam power generation is to expand the slightly hot water (about 150 degrees Celsius) obtained from the ground through a single or multiple sections. There is a certain amount of steam of hot water, and the separator is used to remove the hot water to take out the steam therein, and the steam is guided to the steam turbine generator via the pipeline to drive the steam turbine generator to generate electricity.

Flash-type geothermal generator set for timing when it comes to high-density supercritical fluids. This type of generator set is designed to be encountered when deep geothermal power generation. Mainly because of deep geothermal power generation, the depth of the exploration well will exceed 3000~4000 meters below the surface, so the general expected geothermal source: its underground rock layer should belong to a high temperature gradient heat source such as igneous rock, which may reach more than 300 Celsius. The high temperature. If the above-mentioned high-temperature geothermal fluid is successfully obtained, and the geothermal fluid is smoothly taken to the surface by an excellent insulation and insulation method, in the thermodynamic viewpoint of the power generation facility, the fluid encountered in the pretreatment is near-critical water and steam. The existing mixed phase flow.

In this system, because the temperature of the geothermal fluid itself is high enough, in this system, it is not necessary to use another low-boiling working fluid, and the geothermal fluid can be directly integrated with the turbine to generate electricity. The geothermal fluid obtained in the production well in Figure 2 is a miscible water vapor of more than 375 degrees Celsius. This kind of supercritical fluid geothermal power generation, similar to the double-cycle geothermal power generation, is the same as entering the flash tank 95. The only fluid in the flasher 95 is supercritical geothermal steam. Because the flasher 95 has a large low pressure space, the high temperature and high pressure supercritical water vapor will rapidly depressurize in this space, and the flash will form a separation of water and water vapor.

Therefore, the flasher 95 is sometimes referred to in the literature as a separator, that is, the saturated water vapor is separated into hot water and high pressure unsaturated water vapor. The separated unsaturated high pressure water vapor in the figure is the working fluid required for power generation in the system. Therefore, this high pressure steam is introduced into the turbine 96 to drive the generator 97 to generate electricity. This water vapor is then condensed back into water using a condenser 98 at the rear end of the turbine 96. The hot water separated by the flasher 95 can be reinjected into the re-injection well together with the aforementioned condensed water if its temperature is already low.

A related patent document or technical literature for geothermal heat extraction is as follows: For example, Taiwan Patent Publication No. TW201534817 discloses a geothermal wet steam power generation system, as shown in FIG. 3, which includes a working fluid supply module 10, a steam power generation module 20, and a working fluid. The switching module 30, the heat exchange evaporator 40, and the condenser 50 are switched.

The working fluid supply module 10 is for supplying natural hot water, hot water steam and low boiling point artificial working fluid from a geothermal heat source production well 60. The steam power module 20 includes a turbine assembly 20a. The working fluid switching module 30 is configured to switch the natural hot water steam in the geothermal heat source production well 60 to the steam power generation module 20, drive the turbine assembly to operate with the hot water steam, and cause the generator 21 to generate electricity, and switch the selection. The gaseous artificial working fluid is input to the steam power generation module 20 to drive the turbine assembly to operate to cause the generator 21 to generate electricity. The heat exchange evaporator 40 is used to heat the liquid artificial working fluid to a gaseous state. The condensing machine 50 is configured to cool the steam and the artificial working fluid which have been outputted by the steam power generation module 20 into a liquid for recycling, and can respond to the change of the heat source state of the geothermal heat to fully utilize the geothermal heat source. The purpose of power generation performance.

However, the patent document TW201534817 only discloses that the working fluid switching module 30 can switch to select different working fluids to be supplied to the same steam power generation module 20 in response to changes in the state of the heat source, thereby achieving the technology of fully utilizing the heat generation efficiency of the geothermal heat source. This patent document does not disclose that the hot water around the bottom end of the heat pipe is accelerated to increase the heat extraction efficiency of the geothermal well.

For example, Taiwan Patent Publication No. TW201305512 discloses a double-casing hot heating circulation system, as shown in FIG. 4, which is a source of hot water extracted from a geothermal well 120, and can be recharged after use of waste heat tail water or cold water. A preferred embodiment of the geothermal heating circulation system to the geothermal well 120 (where the geothermal water source is located) comprises a first water pipe 101 and a second water pipe 102 disposed in the first water pipe 101, wherein: A water pipe 101 is a metal pipe, and the first end 111 of the first water pipe is directly penetrated into the geothermal well 120. The geothermal water source, the second end 112 of the opposite first water pipe extends to the ground and is connected to a device 110, such as a geothermal generator set or a water storage tank, and forms a first between the first water pipe 101 and the second water pipe 102. The passage 113 is such that the first passage 113 is used to extract a geothermal water source. The second water pipe 102 is also a metal pipe, and the first end 121 of the second water pipe extends in the first water pipe 101 to the geothermal water source, and the second end 122 of the opposite second water pipe extends to the ground. Connected to the device 110, and a second passage 123 is formed in the second water pipe 102, so that the second passage 123 can be used to recharge the used waste heat tail water to the geothermal water source. Thereby, the double-casing hot heat circulation system disclosed in the patent document TW201305512 is constructed.

A preferred embodiment of the first water pipe 101 includes a plurality of first through holes 114 in the wall of the first end of the first water pipe 111. The first through hole 114 is configured to facilitate the extraction of hot water under the ground. Then unified from the first through hole 114 to the ground. When the dual-casing hot heating circulation system of the patent document is used, the first channel 113 of the first water pipe 101 can be used to extract the geothermal water source, and the geothermal water can be sent to the geothermal generator set or the water storage tank on the ground to utilize the geothermal heat. The heat of water is used for power generation or for other purposes.

However, the plurality of first through holes disclosed in the patent document TW201305512 cannot accelerate the circulation of hot water around the bottom end of the first water pipe (heat take-up pipe) to increase the heat extraction efficiency of the geothermal well.

In view of this, there is a need to provide a geothermal downhole heat extraction device and method to effectively solve the aforementioned problems.

The main object of the present invention is to provide a geothermal downhole heat take-up device and method. The geothermal downhole heat take-up device of the first embodiment of the present invention utilizes a plurality of valves (ie, eddy current generating units) to enable the bottom end of the outer tube to be The hot water accelerates the cycle and increases the heat efficiency of the geothermal well. The geothermal downhole heat take-up device of the second embodiment of the present invention can utilize a propulsion turbine (ie, a vortex generating unit) The hot water around the bottom end of the heat pipe accelerates the cycle, increasing the heat efficiency of the geothermal well.

In order to achieve the above object, a first embodiment of the present invention provides a geothermal downhole heat extraction device, comprising: a heat extraction tube, comprising a double tube having an inner tube and an outer tube, the inner tube being located inside the outer tube, and The bottom end of the inner tube is connected to the bottom end of the outer tube; wherein the bottom end of the outer tube is provided with a plurality of valves (that is, a vortex generating unit), when the working fluid reaches the gas flashing point, and the generated When the pressure of a large amount of gas is greater than the pressure of the geothermal water source, the pressure difference will push the valves outward to open, generating an outward vortex effect, causing the hot water around the bottom end of the outer tube to accelerate; and when the working fluid is under pressure When the pressure is lower than the source of the geothermal water source, there is no pressure difference to push the valves outward to open, so that the working fluid can be prevented from contacting the hot water source.

The second embodiment of the present invention provides a geothermal downhole heat extraction device, comprising: a heat extraction pipe, the bottom end of the heat pipe is connected to a geothermal water source; wherein the bottom end of the heat pipe is mounted to drive a turbine (that is, a vortex generating unit), When the pusher turbine is activated, an outward vortex effect is created, causing the hot water around the bottom end of the heat take-up tube to accelerate.

In addition, the geothermal heat extraction method of the present invention comprises the steps of: providing a heat extraction tube having a bottom end and a ground end; and generating an outward vortex effect at the bottom end of the heat extraction tube, causing the bottom of the heat extraction tube The hot water around the end accelerates the cycle.

The invention is characterized in that the geothermal downhole heating device utilizes a plurality of valves (that is, a vortex generating unit) to accelerate the circulation of hot water around the bottom end of the outer tube, increase the heat extraction efficiency of the geothermal well; or take heat in the geothermal well. The device utilizes a propulsion turbine (ie, a vortex generating unit) to accelerate the circulation of hot water around the bottom end of the heat extraction tube, thereby increasing the heat extraction efficiency of the geothermal well.

The above and other objects, features, and advantages of the present invention will become more apparent from the accompanying drawings.

10‧‧‧Working fluid supply module

20‧‧‧Steam Power Module

20a‧‧‧ Turbine components

21‧‧‧ Generator

30‧‧‧Working fluid switching module

40‧‧‧Heat exchange evaporator

50‧‧‧Condenser

60‧‧‧ production wells

90‧‧‧Evaporator

91‧‧‧ turbine

92‧‧‧Generator

93‧‧‧Condenser

94‧‧‧Reflow pump

95‧‧‧flasher

96‧‧‧ turbine

97‧‧‧Generator

98‧‧‧Condenser

101‧‧‧First water pipe

102‧‧‧Second water pipe

110‧‧‧ Equipment

111‧‧‧ First end of the first water pipe

112‧‧‧The second end of the first water pipe

113‧‧‧First Passage

114‧‧‧First through hole

120‧‧‧Geothermal well

121‧‧‧The first end of the second water pipe

122‧‧‧ second end of the second water pipe

123‧‧‧second channel

200‧‧‧ heat pipe

210‧‧‧Inside

210a‧‧‧ ground end of the inner tube

210b‧‧‧ bottom end of the inner tube

220‧‧‧External management

220a‧‧‧ ground end of the outer tube

220b‧‧‧The bottom end of the outer tube

230‧‧‧ cold water source

240‧‧‧Power generator

250‧‧‧Working fluid

260‧‧‧ valve

270‧‧ eddy current

280‧‧‧Outer casing

310‧‧‧ heat pipe

310a‧‧‧ Take the ground end of the heat pipe

310b‧‧‧ Take the bottom end of the heat pipe

320‧‧‧Refill tube

320a‧‧‧Returning the ground end of the pipe

320b‧‧‧ bottom of the reinjection tube

330‧‧‧Power generator

330a‧‧‧Importation of power generation units

330b‧‧‧Exports of power generation units

340‧‧‧ Geothermal fluid

350‧‧‧Promoting the turbine

360‧‧‧ screen

370‧‧‧ eddy current

380a‧‧‧Outer casing

380b‧‧‧Outer casing

A‧‧‧Geothermal downhole heating device

B‧‧‧Geothermal downhole heating device

1 is a schematic structural view of a conventional double-circulating geothermal generating set; FIG. 2 is a schematic structural view of a conventional flash-type geothermal power generating system; FIG. 3 is a schematic structural view of a conventional hot-humid steam generating system; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 5 is a schematic cross-sectional view of a geothermal downhole heat take-up device according to a first embodiment of the present invention; FIG. 6 is a schematic view of a geothermal downhole heat take-up device according to a first embodiment of the present invention; Figure 7 is a schematic cross-sectional view of a geothermal downhole heat take-up device according to a second embodiment of the present invention; and Figure 8 is a partially enlarged cross-sectional view of the geothermal downhole heat take-up device of the second embodiment of the present invention.

5 and FIG. 6 are schematic diagrams of a geothermal heat extraction device according to a first embodiment of the present invention. In the present embodiment, the geothermal downhole heat taking device A is described as an example of indirect heat taking (the working fluid 250 of the geothermal heat collecting device does not contact the geothermal source of the hot water source).

The geothermal downhole heat removal device A of the present embodiment includes a heat extraction tube 200. The heat pipe 200 includes a double tube having an inner tube 210 and an outer tube 220, and the inner tube 210 is located inside the outer tube 220. The geothermal downhole heat take-up device A further includes an outer sleeve 280 for first extending into the hard formation, and then the heat take-up tube 200 is reinserted into the outer sleeve 280.

In this embodiment, the ground end 210a of the inner tube is connected to a cold water source 230. The bottom end 210b of the inner tube communicates with the bottom end 220b of the outer tube, and the ground end 220a of the outer tube communicates with a power generating device. 240. The cold water source 230 provides a working fluid 250 to absorb geothermal heat, the working fluid 250 (eg, For example, cold water will reach the bottom end 210b of the inner tube from the ground end 210a of the inner tube, and then the working fluid 250 (for example, hot water) is switched from the bottom end 210b of the inner tube to the bottom end 220b of the outer tube, and finally The working fluid 250 (e.g., water vapor and hot water) is returned to the ground end 220a of the outer tube from the bottom end 220b of the outer tube and enters the power generating unit 240 for power generation or for other uses.

Referring to FIG. 6 again, the bottom end 220b of the outer tube of the embodiment is provided with a plurality of valves 260. When the working fluid 250 reaches the gas flash point, the generated gas (water vapor) pressure is greater than the geothermal water source. The pressure difference causes the valves 260 to open outwardly, creating an outward vortex 270 effect, causing the hot water around the bottom end 220b of the outer tube to accelerate; and when the pressure of the working fluid 250 is less than the geothermal source When the pressure is applied, there is no pressure difference to push the valves 260 outward to open, so that the working fluid 250 can be prevented from contacting the hot water source. The geothermal downhole heat take-up device A of the present invention utilizes a plurality of valves 260 to accelerate the circulation of hot water around the bottom end 220b of the outer tube, thereby increasing the heat extraction efficiency of the geothermal well. The valves 260 can be viewed as a vortex generating unit.

Referring to FIG. 7 and FIG. 8 , a schematic diagram of a geothermal heat extraction device according to a second embodiment of the present invention is shown. In the present embodiment, the geothermal downhole heat take-up device B is exemplified by taking water directly (the working fluid of the geothermal heat take-up device B is the geothermal fluid source 340).

The geothermal downhole heat removal device B of this embodiment includes a heat extraction tube 310 and a reinjection tube 320. The geothermal downhole heat taking device B further comprises two outer sleeves, an outer sleeve 380a and an outer sleeve 380b, respectively for extending into the hard formation, and then the heat extraction tube 310 and the reinjection tube 320 are respectively inserted into the outer casing. , in the outer sleeve 380a and the outer sleeve 380b, respectively,

In this embodiment, the ground end 310a of the heat extraction tube is connected to the inlet 330a of a power generating device, and the bottom end 310b of the heat extraction tube is connected to the geothermal water source, and the ground end 320a of the reinjection tube is connected to the outlet 330b of the power generating device. The bottom end 320b of the refill pipe is connected to the geothermal water source. The geothermal fluid 340 (hot water or water vapor) of the geothermal water source will be from the bottom end 310b of the heat extraction tube Upon reaching the ground end 310a of the heat take-up tube, the geothermal fluid 340 of the geothermal source then enters the power generating unit 330 for power generation or for other uses. After the geothermal fluid 340 passes through the power generating device 330, these low temperature geothermal fluids 340 are introduced into the reinjection pipe 320 and reinjected into the ground to restore the resources of the groundwater.

Referring again to FIG. 8, the bottom end 310b of the heat extraction tube of the present embodiment (eg, above the screen 360 of the heat extraction tube) is mounted with a push turbine 350 (eg, a turbine blade) that is generated when the push turbine 350 is activated. The outward vortex 370 effect causes the hot water around the bottom end 310b of the heat take-up tube to accelerate. The geothermal downhole heat take-up device B of the present invention utilizes the push turbine 350 to accelerate the circulation of hot water around the bottom end 310b of the heat take-up tube, thereby increasing the heat extraction efficiency of the geothermal well. The push turbine 350 can be viewed as a vortex generating unit.

Accordingly, the geothermal heat extraction method of the present invention comprises the steps of: providing a heat extraction tube having a bottom end and a ground end; and generating an outward vortex effect at a bottom end of the heat extraction tube by a vortex generating unit , causing the hot water around the bottom end of the heat pipe to accelerate the cycle.

In the above, it is merely described that the present invention is an embodiment or an embodiment of the technical means for solving the problem, and is not intended to limit the scope of implementation of the present invention. That is, the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or the scope of the invention are covered by the scope of the invention.

200‧‧‧ heat pipe

210‧‧‧Inside

210b‧‧‧ bottom end of the inner tube

220‧‧‧External management

220b‧‧‧The bottom end of the outer tube

260‧‧‧ valve

270‧‧ eddy current

280‧‧‧Outer casing

Claims (10)

A geothermal downhole heating device comprises: a heat extraction tube, wherein a bottom of the heat extraction tube is mounted with a vortex generating unit for generating an outward vortex effect at a bottom end of the heat extraction tube, causing a bottom end of the heat extraction tube The hot water accelerates the cycle. The geothermal downhole heat removal device of claim 1, wherein: the heat extraction tube comprises a double tube with an inner tube and an outer tube, the inner tube is located inside the outer tube, and the bottom end of the inner tube is connected to The bottom end of the outer tube; the vortex generating unit is a plurality of valves, the bottom end of the outer tube is provided with the valves, when the working fluid reaches the gas flashing point, and the pressure of the generated large amount of gas is greater than the geothermal water source During the pressure, the pressure difference will push the valves outward to open, creating an outward vortex effect, causing the hot water around the bottom end of the outer tube to accelerate; and when the pressure of the working fluid is less than the pressure of the geothermal source, There is no pressure difference to push the valves outward to open, thus avoiding the working fluid from contacting the hot water source. The geothermal downhole heat removal device of claim 2, wherein the ground end of the inner tube is connected to a cold water source. The geothermal downhole heat removal device of claim 2, wherein the ground end of the outer tube is connected to a power generating device. The geothermal downhole heat removal device of claim 2, wherein the working fluid of the geothermal downhole heat receiving device does not contact the geothermal fluid of the geothermal water source. The geothermal downhole heat removal device of claim 1, wherein the vortex generating unit is a propulsion turbine, and the bottom end of the heat extraction tube is connected to a geothermal water source, and when the propulsion turbine is activated, an outward vortex effect is generated. , causing the hot water around the bottom end of the heat pipe to accelerate the cycle. The geothermal downhole heat removal device of claim 6, wherein the ground end of the heat extraction tube is connected to an inlet of a power generation device. The geothermal downhole heat removal device of claim 6, wherein the geothermal downhole heat removal device further comprises a reinjection pipe, the ground end of the reinjection pipe is connected to the outlet of the power generation device, and the bottom end of the reinjection pipe Connected to geothermal water source. The geothermal downhole heat removal device of claim 6, wherein the heat extraction tube comprises a screen tube, the screen tube is located at a bottom end of the heat extraction tube, and the push turbine is mounted above the screen tube. A geothermal downhole heat extraction method comprising the steps of: providing a heat extraction tube having a bottom end and a ground end; and generating an outward vortex effect at a bottom end of the heat extraction tube, causing heat around the bottom end of the heat extraction tube The water accelerates the cycle.