Underground storage system and underground storage method

Abstract

This system provides an underground storage system that can effectively utilize the hot water generated during CCS (Carbon Capture and Storage) operations. [Solution] The underground storage system 1 comprises an injection well 10 for injecting carbon dioxide from the surface into an aquifer 2, a production well 20 for pumping up hot water from the aquifer 2, a transport vehicle 40 equipped with a heat-insulating storage tank 41, and a water supply facility 50 for supplying the hot water pumped up from the production well 20 to the storage tank 41.

Description

Technical Field

[0001] The present invention relates to a subsurface storage system and a subsurface storage method.

Background Art

[0002] As a countermeasure against global warming, there is CCS (Carbon dioxide Capture and Storage) that separates and recovers carbon dioxide (CO2) from exhaust gas discharged from steel mills, power plants, etc., and stores the carbon dioxide underground. In CCS, carbon dioxide is injected from the ground into an aquifer underground through an injection well. When carbon dioxide is injected into the aquifer, the pressure in the aquifer rises, but the pressure rise in the aquifer can be suppressed by pumping up the groundwater in the aquifer to the ground through a production well (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the production well in the above-mentioned CCS, in order to lower the pressure in the aquifer that rises as the amount of carbon dioxide processed increases, a considerable amount of groundwater (hot water) is pumped up, so the amount of hot water discarded also increases.

[0005] Therefore, an object of the present invention is to provide a subsurface storage system and a subsurface storage method that can effectively utilize the hot water generated during the execution of CCS.

Means for Solving the Problems

[0007] To solve the aforementioned problems, the second invention is an underground storage method comprising injecting carbon dioxide from the surface into an underground aquifer through an injection well, pumping up the hot water from the aquifer to the surface through a production well, and supplying the hot water to a heat-insulating storage tank provided on a transport vehicle.

[0008] To solve the aforementioned problems, the third invention is an underground storage system comprising: an injection well for injecting carbon dioxide from the surface into an underground aquifer; a production well for pumping hot water from the aquifer to the surface; a transport vehicle equipped with a water storage tank; and a water supply facility for supplying the hot water pumped from the production well or room temperature water obtained by lowering the temperature of the hot water to the water storage tank, wherein the water supply facility purifies the hot water or room temperature water and supplies it to the water storage tank of the transport vehicle.

[0009] To solve the aforementioned problems, the fourth invention is an underground storage method comprising injecting carbon dioxide from the surface into an underground aquifer through an injection well, pumping up hot water from the aquifer to the surface through a production well, purifying the hot water or room-temperature water obtained by lowering the temperature of the hot water, and then supplying it to a storage tank provided on a transport vehicle.

[0010] In this invention, carbon dioxide recovered from exhaust gases and the atmosphere can be stored in underground aquifers to reduce the amount of carbon dioxide in the atmosphere. Furthermore, in this invention, hot water can be pumped up from within the aquifer to prevent pressure increases within the aquifer.

[0011] Furthermore, in the first and second inventions, hot water pumped from the aquifer is transported to its destination by a transport vehicle while maintaining its temperature. At the destination, the hot water can then be effectively used as hot water for bathing facilities, heated swimming pools, and water supply, or as heating.

[0012] Furthermore, in the third and fourth inventions, hot or room-temperature water pumped from the aquifer is purified and transported to the destination by a transport vehicle. At the destination, the hot or room-temperature water can then be effectively used as drinking water.

[0013] In the aforementioned underground storage system, it is preferable to form the production well at a depth greater than the bottom of the injection well to prevent carbon dioxide from being incorporated into the hot water. Furthermore, pumping up hot water from a deep underground location has the advantage of increasing the temperature of the hot water. In addition, it is preferable to sufficiently separate the injection well and the production well laterally to further prevent carbon dioxide from being incorporated into the hot water.

[0014] In the aforementioned underground storage system, it is preferable that the transport vehicle is equipped with a carbon dioxide tank. In this configuration, carbon dioxide is filled into a carbon dioxide tank on a transport vehicle and transported to the injection well. Then, the transport vehicle is moved to the production well, where hot water or ambient water is stored in a storage tank, and the hot water or ambient water can be transported to the destination by the transport vehicle. By transporting carbon dioxide and hot water using the same transport vehicle in this way, transportation costs can be reduced. [Effects of the Invention]

[0015] This invention can reduce carbon dioxide in the atmosphere and, furthermore, effectively utilize the hot water generated during CCS (Carbon Capture and Storage) operations. For example, the hot water and room-temperature water generated during CCS operations can be transported to areas with aging water pipes and effectively utilized as hot water or tap water for daily life. [Brief explanation of the drawing]

[0016] [Figure 1]It is a configuration diagram showing a subsurface storage system according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0017] Embodiments of the present invention will be described in detail with appropriate reference to the drawings. FIG. 1 is a configuration diagram showing a subsurface storage system according to an embodiment of the present invention. As shown in FIG. 1, the subsurface storage system 1 includes an injection well 10, a production well 20, a supply facility 30, a transport vehicle 40, and a water supply facility 50. The subsurface storage system 1 of the present embodiment is used for CCS that stores carbon dioxide (CO2) separated and recovered from exhaust gas discharged from a steel mill, a power plant, etc. in the aquifer 2 underground. The aquifer 2 is a deep underground formation composed of sandstone or the like. The aquifer 2 has an impermeable layer where water hardly flows laminated on the upper side, and the aquifer 2 is filled with groundwater. The subsurface storage system 1 of the present embodiment is installed in an area where the geothermal temperature is high and the inside of the aquifer 2 is filled with hot water (groundwater) at about 60 to 90 degrees. [[ID=2(]]

[0018] The injection well 10 is a well for injecting carbon dioxide into the aquifer 2 and reaches the aquifer 2 from the ground. The supply facility 30 includes an air (liquid) supply pipe for sending carbon dioxide into the injection well 10. One end of the supply pipe 31 is connected to the upper end of the injection well 10. Also, the other end of the supply pipe 31 is connected to the carbon dioxide tank 42 of the transport vehicle 40 described later. Carbon dioxide in the carbon dioxide tank 42 is sent into the injection well 10 through the supply pipe 31 by a pump (not shown) provided in the supply pipe 31. The carbon dioxide supplied from the supply facility 30 into the injection well 10 is injected into the aquifer 2 from the perforation formed at the lower end of the injection well 10.

[0019] <000-091>Production well 20 is a well for pumping hot water in the aquifer 2 to the ground and reaches the aquifer 2 from the ground. The hot water in the aquifer 2 flows into the production well 20 through the perforation formed at the lower end of the production well 20. In this embodiment, in order to suppress the temperature drop of the hot water in the production well 20, a heat insulating material is provided on the peripheral wall of the production well 20.

[0020] In this embodiment, the injection well 10 and the production well 20 are arranged at a lateral interval. Also, the production well 20 is formed to a position deeper than the bottom of the injection well 10. The hole at the lower end of the production well 20 is formed below the hole at the lower end of the injection well 10. The lateral interval between the injection well 10 and the production well 20 and the depth of the production well 20 relative to the injection well 10 are set so that the carbon dioxide injected from the injection well 10 into the aquifer 2 is difficult to be contained in the hot water flowing into the production well 20.

[0021] The transport vehicle 40 is a goods vehicle (tank truck) equipped with a water storage tank 41 and a carbon dioxide tank 42. The water storage tank 41 is a tank for storing hot water and normal temperature water. The water storage tank 41 of this embodiment has heat preservation by providing a heat insulating layer. The carbon dioxide tank 42 is a tank for storing liquefied carbon dioxide.

[0022] The water supply facility 50 includes a water supply pipe 51 into which hot water is sent from the production well 20. One end of the water supply pipe 51 is connected to the upper end of the production well 20. Also, the other end of the water supply pipe 51 is connected to the water storage tank 41 of the transport vehicle 40. The hot water in the production well 20 is supplied to the water storage tank 41 through the water supply pipe 51 by a pump (not shown) provided in the water supply pipe 51. In addition, a cooling tank (not shown) for cooling the hot water pumped up from the production well 20 to normal temperature may be provided in the middle of the water supply pipe 51, and normal temperature water may be supplied from the water supply pipe 51 to the water storage tank 41.

[0023] In this embodiment, the water supply system 50 includes a water purification device 52 installed in the middle of the water supply pipe 51 to purify hot water or room temperature water. As a result, hot water or room temperature water is supplied from the water supply pipe 51 to the water storage tank 41 as tap water.

[0024] Next, a method for underground storage using the underground storage system 1 of this embodiment will be described. Carbon dioxide, separated and recovered from exhaust gases emitted from steel mills, power plants, and other sources, as well as from the atmosphere, is liquefied and stored in the carbon dioxide tank 42 of the transport vehicle 40. At this time, the water storage tank 41 of the transport vehicle 40 is empty.

[0025] The transport vehicle 40 is moved from the carbon dioxide recovery location to the injection well 10, and the supply pipe 31 of the supply equipment 30 is connected to the carbon dioxide tank 42. Then, the carbon dioxide in the carbon dioxide tank 42 is sent to the injection well 10 through the supply pipe 31. The carbon dioxide in the injection well 10 is injected into the aquifer 2 from the lower end of the injection well 10.

[0026] Once the carbon dioxide in the carbon dioxide tank 42 has been supplied to the injection well 10, the supply pipe 31 is removed from the carbon dioxide tank 42, and the transport vehicle 40 is moved from the injection well 10 to the production well 20.

[0027] At the production well 20, the water supply pipe 51 of the water supply equipment 50 is connected to the water storage tank 41 of the transport vehicle 40, and the hot water in the aquifer 2 is pumped up from the production well 20 by the water supply equipment 50. Furthermore, the hot water is purified by the water purification device 52. Alternatively, a cooling tank may be installed in the middle of the water supply pipe 51 to bring the hot water to room temperature.

[0028] Hot water is supplied to the storage tank 41 of the transport vehicle 40 via the water supply pipe 51. Then, the transport vehicle 40 is moved to its destination. At the destination, the hot water in the storage tank 41 can be used as hot water for bathing facilities, heated swimming pools, and tap water. If room temperature water is transported to the destination by the transport vehicle 40, the room temperature water can be used as tap water at the destination.

[0029] In the underground storage system 1 and underground storage method described above, carbon dioxide recovered from exhaust gases and the atmosphere is stored in an underground aquifer 2, thereby reducing carbon dioxide in the atmosphere. In this way, reducing greenhouse gases can help prevent global warming. Furthermore, in this embodiment, by pumping up hot water from within the aquifer 2, it is possible to prevent a pressure increase within the aquifer 2. This prevents the impact on the ground due to a pressure increase within the aquifer 2.

[0030] Furthermore, in this embodiment, the hot water pumped from the aquifer 2 is transported to the destination by the transport vehicle 40 while maintaining its temperature. At the destination, the hot water can be effectively used as hot water for bathing facilities, heated swimming pools, water supply, etc. Alternatively, the hot water may be used for heating.

[0031] Furthermore, when hot water pumped from within the aquifer 2, or room-temperature water obtained by lowering the temperature of hot water, is transported to the destination by transport vehicle 40 in a purified state, the hot water or room-temperature water can be effectively utilized as drinking water in areas where water distribution pipes are deteriorated.

[0032] As an example of the present invention, the lateral distance between the injection well 10 and the production well 20 is set to 1000m. Furthermore, the bottom depth of the injection well 10 is set to 1000~1200m, and the bottom depth of the production well 20 is set to 1300~1500m, so that the production well 20 is formed to a position deeper than the bottom of the injection well 10. In this case, if the ground temperature gradient is 3℃ / 100m, the ground temperature around the lower end of the production well 20 will be 55~65℃. Under the aforementioned conditions, if 1 million tons of carbon dioxide are injected annually into the aquifer 2 from the injection well 10, approximately 16,000 to 19,000 m³ of hot water at 60°C will be produced per day over 25 years. 3 This amount of water can be pumped from production well 20. This is based on the average household water usage of 0.3 m³ per day. 3 Considering this, it is equivalent to the daily water usage of approximately 60,000 households.

[0033] In this embodiment, the injection well 10 and the production well 20 are positioned sufficiently far apart laterally, and the production well 20 is formed to a depth greater than the bottom of the injection well 10. This makes it less likely for carbon dioxide to be contained in the hot water in the production well 20. Another advantage is that the temperature of the hot water is higher because it is pumped up from a deep underground position.

[0034] The transport vehicle 40 in this embodiment is equipped with a water storage tank 41 and a carbon dioxide tank 42. In this configuration, carbon dioxide is filled into the carbon dioxide tank 42 of the transport vehicle 40 and transported to the injection well 10. Then, the transport vehicle 40 is moved to the production well 20, where hot water or ambient water is stored in the water storage tank 41, and the hot water or ambient water can be transported to the destination by the transport vehicle 40. By transporting carbon dioxide and hot water by the same transport vehicle 40 in this way, transportation costs can be reduced.

[0035] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from its spirit. The transport vehicle 40 in this embodiment is equipped with a water storage tank 41 and a carbon dioxide tank 42. However, carbon dioxide may be transported to the injection well 10 by a transport vehicle 40 equipped only with a water storage tank 41, and hot water may be transported from the production well 20 to the destination by a transport vehicle 40 equipped only with a carbon dioxide tank 42.

[0036] In this embodiment, the hot water pumped from the production well 20 is purified by the water purification device 52. However, if there are no problems with the quality of the hot water, the hot water pumped from the production well 20 may be supplied to the storage tank 41 of the transport vehicle 40 without purification. [Explanation of symbols]

[0037] 1. Underground Storage System 2 Aquifer 10. Injection well 20 production wells 30 Supply equipment 31 Supply pipe 40 Transport Vehicles 41 Water storage tank 42 Carbon dioxide tanks 50 Water supply equipment 51 Water pipe 52 Water purification system

Claims

1. An injection well for injecting carbon dioxide from the surface into an underground aquifer, A production well for pumping hot water from the aquifer to the surface, A transport vehicle equipped with a water storage tank that has heat retention properties, An underground storage system characterized by comprising a water supply facility that supplies the hot water pumped from the production well to the storage tank.

2. An injection well for injecting carbon dioxide from the surface into an underground aquifer, A production well for pumping hot water from the aquifer to the surface, A transport vehicle equipped with a water storage tank, The facility includes a water supply system that supplies the hot water pumped from the production well or room-temperature water obtained by lowering the temperature of the hot water to the storage tank, The underground storage system is characterized in that the water supply equipment purifies the hot water or the room temperature water and supplies it to the storage tank of the transport vehicle.

3. The underground storage system according to claim 1 or 2, characterized in that the production well is formed to a depth greater than the bottom of the injection well.

4. The underground storage system according to claim 1 or 2, characterized in that the transport vehicle is equipped with a carbon dioxide tank.

5. An underground storage method characterized by injecting carbon dioxide into an underground aquifer from the surface through an injection well, pumping up hot water from the aquifer to the surface through a production well, and supplying the hot water to a heat-insulating storage tank provided on a transport vehicle.

6. An underground storage method characterized by injecting carbon dioxide into an underground aquifer from the surface through an injection well, pumping hot water from the aquifer to the surface through a production well, purifying the hot water or room-temperature water obtained by lowering the temperature of the hot water, and then supplying it to a storage tank equipped on a transport vehicle.

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