JP2008238054A - Underground storage system of carbon dioxide gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To feed carbon dioxide gas into an aquifer under pressure in a state that the carbon dioxide gas is dissolved in a solvent (seawater or water) at a high concentration near the saturated concentration to stably store and isolate the carbon dioxide gas in the aquifer for a long time. <P>SOLUTION: An underground storage system of carbon dioxide gas comprises a carbon oxide gas compression device 2 for compressing carbon oxide gas into a liquid or a supercritical state, a pressure pump 3 for compressing and carrying the solvent comprising seawater and/or water, one or more dissolving tanks 4 for receiving injection of the compressed carbon dioxide gas and solvent and dissolving the carbon dioxide gas in the solvent to generate carbon dioxide gas dissolved water, and an injection well 5 penetrating from the ground surface to the aquifer to feed the generated carbon dioxide gas dissolved water into the underground aquifer under pressure. In the dissolving tank 4, a carbon dioxide gas injection port 11 through which the carbon dioxide gas fed from the carbon oxide gas compression device 2 is injected, and a solvent injection port 12 through which the solvent fed from the solvent pressure pump 3 is injected are formed in the bottom of a closed container 10, and a granular filler 16 is filled into the container 10. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In order to contribute to the reduction of carbon dioxide, which is one of the greenhouse gases that cause global warming, the present invention presses carbon dioxide separated and recovered from a large-scale emission source of carbon dioxide into the ground. And a carbon dioxide underground storage system for long-term and stable storage and sequestration.

  Conventionally, when storing carbon dioxide separated and recovered from exhaust gas in an oil field, gas field, or aquifer that is depleted in the ground, as described in Non-Patent Documents 1 and 2 below, Attempts have been made to compress it into a liquid or supercritical state and press it into the ground through an injection well. Generally, this carbon dioxide gas is injected into a reservoir with a depth of 800m or more to maintain the supercritical state of carbon dioxide gas (in the case of carbon dioxide, the temperature is 31 ° C or higher and the pressure is 7.4MPa or higher), and the carbon dioxide gas density is increased. And efficient storage.

  However, since the carbon dioxide in the supercritical state has a lower specific gravity than the surrounding groundwater and moves upward by buoyancy, the shape of the aquifer that stores the carbon dioxide gas is a dome shape, and the carbon dioxide that floats in the upper center is It was necessary that a sealing layer (cap lock) to be trapped was formed. However, in oil fields and gas fields, it is generally confirmed that the reservoir has a trap structure that is a combination of the seal layer and the dome shape, but it is possible to find an aquifer that meets the conditions in nature. It has become a challenge. For this reason, there has been a demand for a method for expanding the applicable conditions and storing and isolating carbon dioxide gas in the ground in a stable manner over a long period of time.

On the other hand, as a method of pressurizing carbon dioxide into the ground, carbon dioxide boosted by a CO ₂ booster and water pressurized by a pump are introduced into the pipe from the top of the pipe penetrating from the ground surface into the ground. Including the method described in Patent Document 1 described below, which is injected while being mixed and mixed, and the method described in Patent Document 2 described below, wherein carbon dioxide is dissolved in water by a mixer in the underground layer of a gas field or oil field, including carbon dioxide gas There exists the method of the following patent document 3, etc. which make gas microbubble and disperse | distribute it in water or seawater, and isolate | separate the carbon dioxide gas made into microbubble on the ground. In any of these methods, a seawater or water solvent and carbon dioxide are injected into the aquifer, and the carbon dioxide is dissolved in the solvent and stored in the aquifer.
IPCC, “IPCC Special Report on Carbon Dioxide Capture and Storage”, Chapter 5, 2005, Cambridge University Press Shinichi Ozeki, Koji Kano, “Towards the realization of“ CO2 underground storage ”business-Expectations for upstream technology of oil and natural gas”, “Oil and natural gas review”, Petroleum natural gas and metal minerals Resource Organization, 2006.7, vol.40 No.4, p57-70 JP-A-6-170215 JP-A-3-258340 JP 2004-50167 A

  However, in the methods described in Patent Documents 1 to 3, carbon dioxide gas is dissolved in a solvent at a high concentration level, so that the specific gravity is heavier than that of the surrounding groundwater. It can be stably stored and sequestered, but if the solvent is only water or the dissolution means is “Merging”, “Mixer”, “Microbubble generator”, depending on the dissolution conditions, the dissolution of carbon dioxide gas The concentration level was considered insufficient, and there was a possibility that the specific gravity could not be increased more than the surrounding groundwater. In addition, depending on the position of dissolution, the amount of carbon dioxide dissolved may not be confirmed.

  Therefore, the main problem of the present invention is to press-fit carbon dioxide-dissolved water into an aquifer and store / isolate it in a state where carbon dioxide is dissolved in a solvent (seawater or water) at a high concentration near the saturation concentration level. It is to provide a carbon dioxide underground storage system.

In order to solve the above-mentioned problem, the present invention according to claim 1 is a carbon dioxide underground storage system for press-fitting into a groundwater aquifer in a state where carbon dioxide gas is dissolved in a solvent, and storing and isolating it. There,
A carbon dioxide gas compression device that compresses carbon dioxide gas to a liquid or supercritical state, a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and the compressed carbon dioxide gas and solvent are injected, and the solvent is One or a plurality of dissolution tanks that dissolve carbon dioxide to form carbon dioxide-dissolved water, and an injection well that penetrates the generated carbon dioxide-dissolved water from the ground surface into the aquifer through the ground. Consisting of
The dissolution tank includes a carbon dioxide gas inlet through which a carbon dioxide gas sent from the carbon dioxide compressor is injected into a lower part of a sealed container, and a solvent inlet through which a solvent sent from the solvent pump is injected. And a discharge port through which the carbon dioxide-dissolved water is discharged is formed in an upper portion of the container, and the container is filled with a granular filler. A geological storage system is provided.

  In the first aspect of the present invention, the dissolution tank is fed into a lower part of a hermetically sealed container from a carbon dioxide gas inlet through which the carbon dioxide gas sent from the carbon dioxide gas compressor is injected, and from the solvent pressure pump. A solvent injection port for injecting the solvent is formed, and a discharge port for discharging the carbon dioxide-dissolved water is formed in the upper part of the container, and the container is filled with a granular filler As a result, carbon dioxide gas (liquid or supercritical state) can be dissolved in the solvent (seawater or water) at a high concentration near the saturation concentration level in this dissolution tank. Since it becomes larger than the surrounding groundwater, carbon dioxide can be stored and isolated in the aquifer for a long time and stably.

  According to a second aspect of the present invention, there is provided the carbon dioxide underground storage system according to the first aspect, wherein the granular filler is any one or a combination of sand, crushed stone, Raschig ring, and saddle.

  In the second aspect of the present invention, as the granular filler to be filled in the dissolution tank, for example, any one of sand, crushed stone, Raschig ring, and saddle or a combination thereof is used.

  As the present invention according to claim 3, the granular filler is, for each type of filler, the amount of carbon dioxide dissolved based on the flow rate of carbon dioxide and solvent and the shape of the dissolution tank, and the pressure in the dissolution tank. The underground storage system for carbon dioxide according to any one of claims 1 and 2, wherein an optimum average particle diameter determined from the loss is provided.

  In the invention of claim 3, the granular filler is, for each type of filler, the amount of carbon dioxide dissolved based on the flow rate of carbon dioxide and solvent and the shape of the dissolution tank, and the pressure loss in the dissolution tank. The average particle size determined from the above is used, and when the average particle size is the above-mentioned optimal average particle size, the dissolution efficiency is excellent.

  According to a fourth aspect of the present invention, in the melting tank, one or a plurality of rectifying plates having a plurality of apertures formed so as to partition the flow path are provided in the filling region of the filler. The underground storage system of the carbon dioxide gas in any one of -3 is provided. In the invention according to claim 4, by providing the current plate, dissolution of carbon dioxide gas in the dissolution tank is promoted.

  As the present invention according to claim 5, undissolved carbon dioxide gas and carbon dioxide gas at a saturated concentration with respect to the total amount of carbon dioxide dissolved water fed in the middle of the flow path from the dissolution tank to the injection well. A separation tank for separating the dissolved carbon dioxide-dissolved water is disposed, and a carbon dioxide pressure feeding device for returning the separated undissolved carbon dioxide to an intermediate flow path between the carbon dioxide compression apparatus and the dissolution tank. The underground storage system of the carbon dioxide gas in any one of Claims 1-4 arrange | positioned is provided.

  The invention of claim 5 is directed to separating the undissolved carbon dioxide in the separation tank for the total amount of carbon dioxide-dissolved water produced in the dissolution tank, and returning the undissolved carbon dioxide to the dissolution tank. By making it, it becomes possible to press-fit into the ground in a state where carbon dioxide gas is dissolved in a solvent (seawater or water) at a saturated concentration level. This carbon dioxide-dissolved water has a greater specific gravity than the groundwater around the aquifer, and even when injected into the aquifer, carbon dioxide does not rise and is stored and sequestered in the aquifer in a long-term and stable manner. To be able to.

  As the present invention according to claim 6, a plurality of the dissolution tanks are arranged, and some of these dissolution tanks are fed into the carbon dioxide dissolved water fed in the middle of the flow path from the dissolution tank to the injection well. On the other hand, a separation tank for separating undissolved carbon dioxide and carbon dioxide-dissolved water in which carbon dioxide is dissolved at a saturated concentration is provided, and the separated undissolved carbon dioxide is compressed by the carbon dioxide gas. The carbon dioxide gas pressure feeding apparatus which returns to the intermediate flow path of an apparatus and a dissolution tank is arrange | positioned, and about the remaining dissolution tank, the flow path is connected to the downstream of the said separation tank. A carbon dioxide underground storage system is provided.

  In the invention according to claim 6, the carbon dioxide gas is dissolved in the groundwater, and is injected into the underground aquifer in a state containing some undissolved carbon dioxide gas (up to 5% of the solvent weight). The undissolved carbon dioxide gas is controlled to be dissolved in the groundwater. In addition, as a melt | dissolution period of the carbon dioxide gas with respect to groundwater, only the period when the injection of a carbon dioxide gas is performed and the flow of the carbon dioxide gas within the aquifer is considered. In contrast to the invention described in claim 5, the invention described in claim 6 can reduce the amount of seawater or water used and the energy used for the treatment per unit weight of carbon dioxide gas.

  The present invention according to claim 7 is configured such that the carbon dioxide dissolved water discharged from the dissolution tank is press-fitted into an underground aquifer while containing undissolved carbon dioxide. 4. A carbon dioxide underground storage system according to any one of 4 is provided.

  The invention of claim 7 further promotes the reduction of the amount of seawater or water used and the energy used for the treatment per unit weight of carbon dioxide. In the dissolution tank, by adjusting the amount of carbon dioxide introduced into the dissolution tank so that there is no undissolved carbon dioxide in the aquifer after the injection period into the aquifer, a separation device becomes unnecessary, It is possible to reduce the amount of seawater or water used and the energy used.

  As described above in detail, according to the present invention, carbon dioxide can be stored and isolated in the aquifer for a long time and stably in a state where carbon dioxide gas is dissolved in a solvent at a high concentration near the saturation concentration level.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The carbon dioxide underground storage system 1 according to the present invention dissolves carbon dioxide separated and recovered from a large-scale emission source of carbon dioxide in a solvent (seawater or water) at a high concentration near the saturation concentration level. It is for containment in the underground aquifer in a state, and for long-term and stable storage and isolation.

As described above, in the present invention, carbon dioxide is dissolved in a solvent at a high saturation concentration level so that the specific gravity is heavier than that of the surrounding groundwater, and carbon dioxide is stored and sequestered in the aquifer in a long-term and stable manner. Therefore, the amount of carbon dioxide dissolved is 40 to 50 kg, preferably 45 to 50 kg per 1 m ³ of the solvent.

  The pressure in the system is such that the carbon dioxide is dissolved in a liquid or supercritical state, and the carbon dioxide dissolved water is injected into the underground aquifer. Considering the injection pressure and the pressure loss of the piping system, a high pressure state of 8 MPa or more is maintained.

[First configuration pattern]
FIG. 1 is a conceptual diagram showing a first configuration pattern of a carbon dioxide underground storage system 1 according to the present invention.
As shown in FIG. 1, the underground storage system 1 includes a carbon dioxide gas compression device 2 that compresses carbon dioxide gas to a liquid or supercritical state, and a pressure feed pump 3 that compresses and conveys seawater and / or a solvent composed of water. The compressed carbon dioxide gas and solvent are injected, the carbon dioxide gas is dissolved in the solvent to form carbon dioxide-dissolved water, and the generated carbon dioxide-dissolved water is submerged in the ground. It consists mainly of an injection well 5 penetrating from the ground surface pressed into the aquifer to the aquifer.

  In the present embodiment, a plurality of the dissolution tanks 4 are installed in order to promote the dissolution of carbon dioxide gas. However, a single unit may be used as necessary.

  As shown in FIG. 2, the dissolution tank 4 includes a carbon dioxide gas inlet 11 into which a carbon dioxide gas sent from the carbon dioxide gas compression device 2 is injected into a lower portion of a sealed container 10, and the solvent pressure pump. 3 is formed, and a discharge port 13 for discharging the carbon dioxide-dissolved water is formed in the upper portion of the container 10. The perforated plates 14 and 15 for partitioning the inside of the container 10 in the vertical direction are respectively arranged on the upper side, and a granular filler 16 is filled between the perforated plates 14 and 15.

  The filler 16 is for accelerating the stirring of the solvent and the carbon dioxide gas and improving the efficiency of the dissolution of the carbon dioxide gas. For example, the filler 16 may be any one or a combination of sand, crushed stone, Raschig ring, and saddle. it can. The Raschig ring is a cylinder-shaped packing made of ceramic, plastic, metal, carbon, etc., which is used in packed towers and can be used in general. The saddle is a horseshoe-shaped packing made of ceramic or the like, and is generally formed so that the pressure loss is smaller than that of the Raschig ring.

Moreover, the said filler 16 is the optimal average determined from the amount of carbon dioxide dissolution determined based on the flow volume of a carbon dioxide gas and a solvent, and the shape of the said dissolution tank, and the pressure loss in the said dissolution tank for every kind of filler. It is preferable to use a particle size. Specifically, for each type of filler, after experimentally obtaining the following two relationships with respect to the average particle diameter of the filler, the pressure loss allowed in the dissolution tank (inlet and outlet of the dissolution tank) For the difference in pressure between the two, an average particle size with the largest amount of dissolution is selected as the optimum average particle size.
(1) The relationship of the amount of carbon dioxide dissolved with respect to the average particle diameter of the filler in the predetermined flow rate of carbon dioxide and solvent and the shape of the dissolution tank.
(2) Relationship between dissolution tank pressure loss and average filler particle size.

  Generally, the properties of the filler with respect to the average particle size are as follows: (1) Given the flow rate of carbon dioxide gas and solvent and the shape of the dissolution tank, the smaller the average particle size of the filler, the more the amount of carbon dioxide dissolved To increase. (2) On the other hand, as the average particle size of the filler becomes finer, the pressure loss due to the flow of carbon dioxide and solvent in the dissolution tank increases, and the energy used to secure a constant flow rate tends to increase. There is. Therefore, the average particle size of the filler is selected after comprehensively considering the flow rates of the carbon dioxide gas and the solvent and the shape of the dissolution tank. In addition, when the required amount of carbon dioxide dissolution cannot be determined, it is also considered to take measures such as increasing the size of the dissolution tank.

  By using the filler 16 having the optimum average particle diameter, the carbon dioxide gas is efficiently dissolved.

  As shown in FIG. 2, the container 10 is preferably a sealed vertically long tube. Thereby, it becomes possible to ensure the residence time of the carbon dioxide gas and the solvent in the dissolution tank 4. Moreover, it can be set as the structure which has pressure | voltage resistance with respect to the said setting pressure in a system, and the production | generation of a carbon dioxide dissolved water can be continuously and stably in a short time.

  Here, the flow in the dissolution tank 4 will be described with reference to FIG. 2. The carbon dioxide gas and the solvent pumped into the container 10 from the carbon dioxide inlet 11 and the solvent inlet 12 are mixed in the lower hopper 17. And enters the filling region of the filler 16 from the lower perforated plate 14 evenly. In the filling region of the filler 16, the solvent and carbon dioxide are sufficiently stirred together with the flow between the fillers 16 to dissolve the carbon dioxide in the solvent and flow upward. Due to this action, when the upper porous plate 15 is reached, carbon dioxide-dissolved water in which carbon dioxide is substantially dissolved in the solvent is generated, and reaches the saturated dissolution level of the solvent. Thereafter, the carbon dioxide-dissolved water that has entered the upper hopper 18 from the upper porous plate 15 is discharged from the discharge port 13.

  In the dissolution tank 4, it is desirable to provide one or a plurality of rectifying plates 19 in which a large number of openings are formed so as to partition the flow path in the filling region of the filler 16. By providing the rectifying plate 19, the flow of the carbon dioxide gas and the solvent by the filler 16 is made uniform, and the dissolution of the carbon dioxide gas in the dissolution tank 4 is improved by increasing the chance of contact between them. The residence time in the dissolution tank 4 and the carbon dioxide gas dissolution amount are in a generally proportional relationship up to the saturation concentration level. Therefore, the apparatus scale is set so that the residence time according to the target dissolution amount is obtained under predetermined operating conditions. It is desirable to set.

  Further, in this first configuration pattern, undissolved carbon dioxide and carbon dioxide are saturated with respect to the total amount of carbon dioxide dissolved water fed in the middle of the flow path from the dissolution tank 4 to the injection well 5. A separation tank 6 that separates the dissolved carbon dioxide dissolved water at a concentration is disposed, and the separated undissolved carbon dioxide is returned to an intermediate flow path between the carbon dioxide compression apparatus 2 and the dissolution tank 4. A carbon dioxide pressure feeding device 7 is provided.

  In this first configuration pattern, the undissolved carbon dioxide content is separated in the separation tank 6 with respect to the total amount of carbon dioxide dissolved water generated in the dissolution tank 4, and this undissolved carbon dioxide content is separated into the dissolution tank 4. By returning, it becomes possible to press-fit into the ground in a state where carbon dioxide gas is dissolved in a solvent (seawater or water) at a saturated concentration level. This carbon dioxide-dissolved water has a greater specific gravity than the groundwater around the aquifer, and even when injected into the aquifer, carbon dioxide does not rise and is stored and sequestered in the aquifer in a long-term and stable manner. To be able to.

  As shown in FIG. 3, the separation tank 6 is erected in a sealed container 20 at a predetermined height from the lower surface and connected to a flow path of carbon dioxide dissolved water that has passed through the dissolution tank 4. A tube 21 is provided, and the inside of the container 20 is substantially filled with the carbon dioxide-dissolved water so that the undissolved carbon dioxide is gravity separated upward, and the undissolved carbon dioxide gas is discharged to the upper part of the container 20. An undissolved carbon dioxide gas discharge port 22 is formed, and a carbon dioxide gas-dissolved water discharge port 23 for discharging the carbon dioxide-dissolved water after the undissolved carbon dioxide gas is separated is formed below the container 20. Yes.

  Each flow rate of the solvent and carbon dioxide gas per dissolution tank is the weight of the injected carbon dioxide gas and solvent with respect to the total flow rate determined by the volume of the dissolution tank 4 and the residence time of the carbon dioxide gas and solvent in the dissolution tank 4. It can be determined from the ratio (carbon dioxide weight / solvent weight). At this time, the weight ratio between the carbon dioxide gas and the solvent is determined based on the desired amount of carbon dioxide dissolved. The relationship between the weight ratio of the carbon dioxide gas and the solvent and the dissolved amount of the carbon dioxide gas is determined by a water flow test performed in advance.

  As will be described in detail in an example at a later stage, the dissolution concentration in the dissolution tank 4 affects the weight ratio of the injected carbon dioxide gas to the solvent (carbon dioxide weight / solvent weight). Specifically, as the weight ratio to be injected increases, the dissolution concentration in the dissolution tank 4 tends to increase. For the purpose of promoting the dissolution of carbon dioxide, the injection weight ratio of carbon dioxide and solvent is: It is preferable to set it larger than the target value of the carbon dioxide gas dissolution concentration.

  In the first configuration pattern, as described above, the carbon dioxide dissolved water discharged from all the dissolution tanks 4, 4... Is injected into the separation tank 6. Undissolved carbon dioxide contained in the discharged carbon dioxide-dissolved water is completely separated, and carbon dioxide-dissolved water in a state where the carbon dioxide is completely dissolved in the solvent is injected into the injection well 5.

[Second configuration pattern]
The second configuration pattern is the same as the first configuration pattern in the main configuration of the underground storage system 1 except for the following points. That is, as shown in FIG. 4, a plurality of the dissolution tanks 4 are arranged, and some of these dissolution tanks 4, 4... Are sent in the middle of the flow path from the dissolution tank 4 to the injection well 5. A separation tank 6 for separating undissolved carbon dioxide gas and carbon dioxide-dissolved water in a state where the carbon dioxide gas is dissolved at a saturated concentration is disposed with respect to the supplied carbon dioxide-dissolved water, and the separated tank 6 is separated. A carbon dioxide pressure feeding device 7 for returning undissolved carbon dioxide gas to the intermediate flow path between the carbon dioxide compression apparatus 2 and the dissolution tank 4 is disposed, and the remaining dissolution tank is connected to the downstream side of the separation tank 6. It becomes the composition which is done.

  In this second configuration pattern, in order to dissolve carbon dioxide in groundwater, it is injected into the underground aquifer with some undissolved carbon dioxide (up to 5% of the solvent weight). Control is performed so that undissolved carbon dioxide is dissolved in groundwater. In addition, as a melt | dissolution period of the carbon dioxide gas with respect to groundwater, only the period when the injection of a carbon dioxide gas is performed and the flow of the carbon dioxide gas within the aquifer is considered.

  Compared with the first configuration pattern, the second configuration pattern can reduce the amount of seawater or water used and energy used for processing per unit weight of carbon dioxide gas.

[Third configuration pattern]
As shown in FIG. 5, the third configuration pattern is the same as the first configuration pattern in that the carbon dioxide-dissolved water discharged from the dissolution tank 4 is left in the state containing undissolved carbon dioxide, It is different in that it is pressed into the aquifer inside.

  In the third configuration pattern, the amount of seawater or water required for processing per unit weight of carbon dioxide or water and the energy used are further reduced. In this third configuration pattern, in order to dissolve carbon dioxide in groundwater, undissolved carbon dioxide (up to 5% of the solvent weight) is dissolved in groundwater in the underground aquifer. It is something to control. As a dissolution period of carbon dioxide gas in the groundwater, only a period in which undissolved carbon dioxide gas is injected and carbon dioxide flows in the aquifer is considered. In the dissolution tank 4, by adjusting the amount of carbon dioxide introduced into the dissolution tank so that there is no undissolved carbon dioxide in the aquifer after the above period, a separation device becomes unnecessary, and seawater or It is possible to reduce water consumption and energy consumption.

  In order to verify the dissolution state of carbon dioxide gas by the underground storage system 1, a carbon dioxide dissolution experiment was conducted using the experimental apparatus shown in FIG.

  As shown in FIG. 6, the experimental apparatus pressurizes the carbon dioxide in the carbon dioxide cylinder 30 by the carbon dioxide compressor 2 and injects it into the dissolution tank 4, and pressurizes the salt water in the salt water tank 31 by the solvent pump 3. The carbon dioxide is dissolved in the dissolution tank 4, the carbon dioxide is dissolved in the dissolution tank 4, and the carbon dioxide dissolved water after the carbon dioxide dissolved water is separated from the undissolved carbon dioxide in the separation tank is sampled. Here, the volume of the dissolution tank 4 was 850 ml, and the filler 16 used was a sand-like material having an average particle size of 0.18 mm (particle size 1), 0.63 mm (particle size 2), and 1.32 mm (particle size 3). In the experiment, when the temperature, pressure, salt water flow rate, particle size of the filler 16 and the weight ratio of carbon dioxide and salt water (carbon dioxide weight / salt water weight) were changed, the amount of carbon dioxide dissolved in the sampled carbon dioxide dissolved water was changed. It was measured.

  FIGS. 7 and 8 show the weight ratio of carbon dioxide and salt water (carbon dioxide weight / salt water weight) and carbon dioxide dissolution when injected into the dissolution tank 4 when the salt water flow rate and the particle size of the filler 16 are changed at each temperature. It is a graph which shows the relationship with quantity. As a result, at any of the test temperatures of 29 ° C. and 33 ° C., the amount of carbon dioxide dissolved tends to increase as the weight ratio of carbon dioxide to salt water increases and the particle size of the filler 16 decreases.

  9 to 11 are graphs showing the relationship between the weight ratio and the amount of dissolved carbon dioxide gas when the salt water flow rate and pressure at each temperature are changed. As a result, as described above, as the weight ratio of carbon dioxide and salt water increases, the amount of dissolved carbon dioxide tends to increase, but at a certain weight ratio or more, the amount of dissolved carbon dioxide becomes a substantially constant saturation concentration level, The effectiveness of the underground storage system was confirmed.

  FIG. 12 is a graph showing the relationship between the temperature at each pressure and the amount of carbon dioxide dissolved. As a result, it was confirmed that, under general temperature conditions in the range of 25 ° C. to 40 ° C., the carbon dioxide dissolution amount was not greatly affected.

  FIG. 13 is a graph showing the relationship between the average particle diameter of the filler and the amount of carbon dioxide dissolved at each salt water flow rate. As a result, in this example, the average particle size of the filler is excellent in the dissolution efficiency of carbon dioxide gas by setting the average particle size to 1.0 mm or less.

It is a conceptual diagram of the underground storage system 1 (1st structure pattern) of the carbon dioxide gas concerning this invention. 3 is a longitudinal sectional view of the dissolution tank 4. FIG. 3 is a longitudinal sectional view of a separation tank 6. FIG. It is a conceptual diagram of the carbon dioxide underground storage system 1 (2nd structure pattern) concerning this invention. It is a conceptual diagram of the underground storage system 1 (3rd structure pattern) of the carbon dioxide gas concerning this invention. It is a conceptual diagram of an experimental apparatus. It is a graph which shows the relationship between the weight ratio with respect to the salt water flow rate in a temperature of 29 degreeC, and a particle size, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the weight ratio with respect to the salt water flow rate and particle size at the temperature of 33 degreeC, and a carbon dioxide gas dissolution amount. It is a graph which shows the relationship between the weight ratio with respect to the salt water flow rate in the temperature of 25 degreeC, and a pressure, and a carbon dioxide gas dissolution amount. It is a graph which shows the relationship between the weight ratio with respect to the salt water flow rate and pressure in the temperature of 29 degreeC, and a carbon dioxide gas dissolution amount. It is a graph which shows the relationship between the weight ratio with respect to the salt water flow rate and pressure in the temperature of 33 degreeC, and a carbon dioxide gas dissolution amount. It is a graph which shows the relationship between temperature and the amount of carbon dioxide dissolution. It is a graph which shows the relationship between the average particle diameter of a filler, and the relationship between a carbon dioxide gas dissolution amount.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Underground storage system, 2 ... Carbon dioxide compression apparatus, 3 ... Solvent pump, 4 ... Dissolution tank, 5 ... Injection well, 6 ... Separation tank, 7 ... Carbon dioxide pump, 10 ... Container, 11 ... Carbon dioxide Inlet 12, 12 Solvent inlet, 13 Discharge port 14, 15 ... Perforated plate, 16 ... Filler, 19 ... Rectifier plate, 20 ... Container, 21 ... Inflow pipe, 22 ... Undissolved carbon dioxide discharge port, 23 ... CO2 outlet

Claims (7)

A carbon dioxide underground storage system for pressurizing, storing, and isolating carbon dioxide into a groundwater aquifer in a state of being dissolved in a solvent,
A carbon dioxide gas compression device that compresses carbon dioxide gas to a liquid or supercritical state, a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and the compressed carbon dioxide gas and solvent are injected, and the solvent is One or a plurality of dissolution tanks that dissolve carbon dioxide to form carbon dioxide-dissolved water, and an injection well that penetrates the generated carbon dioxide-dissolved water from the ground surface into the aquifer through the ground. Consisting of
The dissolution tank includes a carbon dioxide gas inlet through which a carbon dioxide gas sent from the carbon dioxide compressor is injected into a lower part of a sealed container, and a solvent inlet through which a solvent sent from the solvent pump is injected. And a discharge port through which the carbon dioxide-dissolved water is discharged is formed in an upper portion of the container, and the container is filled with a granular filler. Underground storage system.   The underground storage system for carbon dioxide gas according to claim 1, wherein the granular filler is any one or a combination of sand, crushed stone, Raschig ring, and saddle.   The granular filler is an optimum average determined from the amount of carbon dioxide dissolved based on the flow rate of carbon dioxide and solvent and the shape of the dissolution tank and the pressure loss in the dissolution tank for each type of filler. The underground storage system for carbon dioxide gas according to claim 1, wherein the particle size is a particle size.   The carbon dioxide gas according to any one of claims 1 to 3, wherein in the dissolution tank, one or a plurality of rectifying plates in which a large number of openings are formed so as to partition the flow path are provided in the filling region of the filler. Underground storage system.   In the middle of the flow path from the dissolution tank to the injection well, undissolved carbon dioxide gas and carbon dioxide dissolved water in a state where the carbon dioxide gas is dissolved at a saturated concentration with respect to the total amount of carbon dioxide dissolved water fed. And a carbon dioxide gas pressure feeding device for returning the separated undissolved carbon dioxide gas to an intermediate flow path between the carbon dioxide gas compression device and the dissolution vessel. The carbon dioxide underground storage system according to any one of the above.   A plurality of the dissolution tanks are arranged, and a part of these dissolution tanks is in the middle of the flow path from the dissolution tank to the injection well, with the undissolved carbon dioxide gas supplied to the carbon dioxide dissolved water supplied. A separation tank that separates the carbon dioxide-dissolved water in a state where the carbon dioxide gas is dissolved at a saturated concentration, and an intermediate flow path between the undissolved carbon dioxide separated by the carbon dioxide compression apparatus and the dissolution tank. A carbon dioxide gas underground storage system according to any one of claims 1 to 4, wherein a carbon dioxide gas pressure feeding device is disposed to return to the remaining dissolution tank, and a flow path is connected to the downstream side of the separation tank.   The carbon dioxide dissolved water discharged from the dissolution tank is pressed into a groundwater aquifer in a state containing undissolved carbon dioxide as it is. Underground storage system.

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