JP2010201330A - Underground storage system for carbon dioxide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently dissolve carbon dioxide in a solvent and to suppress an increase in the transport cost of carbon dioxide. <P>SOLUTION: This underground storage system for carbon dioxide is constituted by providing a carbon dioxide compressor 2 for compressing carbon dioxide up to a liquid or supercritical state and a pressure sending pump 3 for compressing the solvent to feed the same and installing not only a carbon dioxide dissolving device 40, which is composed of a fine bubble forming device 7 for mixing carbon dioxide with the solvent while converting carbon dioxide to fine bubbles by the shearing force of the solvent flowing through a main flow pipeline and the dissolving tank 4 installed on the rear stage of the fine bubble forming device 7 and dissolving carbon dioxide in the solvent to produce carbon dioxide dissolved water, but also the injection well 5 piercing through the ground up to an aquifer to introduce the formed carbon dioxide dissolved water into the aquifer in the ground under pressure. The carbon dioxide compressor 2 and the solvent pressure sending pump 3 are arranged on the ground separated from the aquifer while the carbon dioxide dissolving device 40 is arranged in the vicinity of the injection well 5, and the carbon dioxide compressor 2, the solvent pressure sending pump 3 and the carbon dioxide dissolving device 40 are each connected by pipelines 41 and 42. <P>COPYRIGHT: (C)2010,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. In general, this carbon dioxide gas is injected into a reservoir with a depth of 800 m or more to maintain the supercritical state of carbon dioxide gas (in the case of carbon dioxide, the temperature is 31 ° C or higher, the pressure is 7.4 MPa or higher), and the density of the carbon dioxide gas is increased. And efficient storage.

  However, supercritical carbon dioxide has a lower specific gravity than the surrounding groundwater and moves upward by buoyancy, so the shape of the aquifer that stores carbon dioxide is dome-shaped, and the carbon dioxide that has floated in the upper center is It was necessary to form a sealing layer (cap lock) to be trapped. However, in oil 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 in the ground for a long term and stably without rising.

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.

  However, in the methods described in Patent Documents 1 to 3 below, 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. 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 concentration of carbon dioxide gas The level was considered insufficient, and there was a risk 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.

  In view of this, the present applicant, in Patent Document 4 below, is a carbon dioxide underground storage system for press-fitting into a groundwater aquifer in a state in which carbon dioxide is dissolved in a solvent, and storing and isolating the system. A carbon dioxide gas compression device that compresses the gas to a liquid or supercritical state, a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, the compressed carbon dioxide gas and the solvent are injected, and the carbonic acid is injected into the solvent. From one or a plurality of dissolution tanks that dissolve gas to form carbon dioxide-dissolved water, and an injection well that penetrates the generated carbon dioxide-dissolved water into the aquifer in the ground through the aquifer The dissolution tank is configured such that a carbon dioxide gas injection port into which carbon dioxide gas sent from the carbon dioxide gas compression device is injected and a solvent sent from the solvent pressure pump are injected into a lower portion of a sealed container. Solvent inlet and formed Together, wherein the carbon dioxide gas dissolved water on top of the container discharge port that is formed ejected, filler particulate in the container is proposed underground storage system carbon dioxide formed is filled.

  According to the following Patent Document 4, carbon dioxide gas can be dissolved in a solvent at a high concentration near the saturation concentration level in the dissolution tank, and the specific gravity of the carbon dioxide-dissolved water becomes larger than that of the surrounding groundwater. Effects such as being able to store and sequester gas in the aquifer for a long time and stably have come to be demonstrated.

JP-A-6-170215 JP-A-3-258340 JP 2004-50167 A JP 2008-238054 A

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

  However, in the case of the dissolution tank in Patent Document 4, in order to promote sufficient dissolution of carbon dioxide gas and to efficiently process a large amount of carbon dioxide gas, there is a problem that the volume of the dissolution tank becomes large, and in the dissolution tank There is a problem that the flow path length of the dissolution tank, that is, the height dimension of the dissolution tank becomes long in order to ensure the residence time.

  In order to solve the above-mentioned problems, the present inventors have made extensive studies, and as a result, have found that it is effective to increase the contact area with the solvent by making carbon dioxide fine. As the microbubble generator, for example, the microbubble generator has been developed. However, since the dissolution of carbon dioxide gas is performed under a high pressure state (8 to 20 MPa) of 8 MPa or more, Those with pressure relief cannot be adopted in principle. In addition, ejector type and swirl type types have not been proven under high pressure conditions, and the mechanism is complicated to apply to high pressure conditions, and reliability and durability have not been proven. is there.

  On the other hand, in the underground storage system described in Patent Document 4, there is no problem when the carbon dioxide emission source and the aquifer are at a short distance. If the dissolution tank is installed in the vicinity of the carbon dioxide emission source, when transporting the carbon dioxide dissolved water generated in the dissolution tank to the injection well, friction due to long-distance transportation in a pipeline, etc. There is a possibility that transportation costs will increase and economic efficiency will deteriorate due to increased loss and increased strength of pipeline facilities by handling high-pressure gas.

  Therefore, as a first problem of the present invention, in a state where carbon dioxide gas is dissolved in a solvent (seawater or water) at a high concentration near the saturation concentration level, the carbon dioxide-dissolved water is pressed into the aquifer and stored / isolated. An object of the present invention is to provide a carbon dioxide underground storage system.

  A second problem is to provide a carbon dioxide underground storage system in which carbon dioxide is efficiently dissolved in a solvent and an increase in transportation cost is suppressed.

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, and a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water,
The carbon dioxide gas supply line is disposed inside the main flow line through which the solvent flows at a predetermined high flow rate, or the carbon dioxide gas supply line that externally fits the main flow line is disposed, A high-pressure carbon dioxide gas refining device that forms pores in the wall surface of the pipe line that partitions the solvent and carbon dioxide gas, and mixes the carbon dioxide gas while making the carbon dioxide gas fine by the shearing force of the solvent flowing through the main flow line, and the high pressure An inlet for the solvent mixed with the carbon dioxide gas is formed in the lower part of the sealed container installed in the latter stage of the carbon dioxide gas bubbler for the use, and the solvent is formed in the upper part of the container. A carbon dioxide gas dissolving device including one or a plurality of dissolution tanks formed with a discharge port through which carbon dioxide dissolved water in which the carbon dioxide gas is dissolved is discharged, and filled with a granular filler in the container Install
It is constructed by installing an injection well penetrating from the ground surface to the aquifer in order to press-fit carbon dioxide dissolved water discharged from the dissolution tank into the underground aquifer,
The carbon dioxide compression device and the solvent pressure pump are disposed on land apart from the aquifer, and the carbon dioxide dissolution device is disposed in the vicinity of the injection well. The carbon dioxide compression device, the solvent pressure pump, and carbon dioxide A carbon dioxide underground storage system is provided in which a melting apparatus is connected to each other by a pipeline.

  The invention described in claim 1 is the case 1 of the underground storage system according to the present invention, and defines the first configuration pattern of the carbon dioxide dissolving apparatus used therefor. Specifically, in case 1 of the underground storage system, the carbon dioxide gas compression device and the solvent pressure pump are arranged on land far from the aquifer, and the carbon dioxide gas dissolving device is arranged in the vicinity of the injection well. The compression device, the solvent pressure pump, and the carbon dioxide gas dissolving device were each connected by a pipeline.

  Further, as a first configuration pattern of the carbon dioxide gas dissolving apparatus used for this, the carbon dioxide gas supply pipe is disposed in the main stream pipe through which the solvent is flowed at a predetermined high flow rate, or the main stream is provided. The carbon dioxide gas supply pipe line that externally fits the pipe line is disposed, pores are formed on the wall surface of the pipe line that partitions the solvent and the carbon dioxide gas, and the carbon dioxide gas is generated by the shearing force of the solvent flowing through the main flow line. A high-pressure carbon dioxide gas bubbler that mixes while making the gas bubbles fine, and the high-pressure carbon dioxide gas bubbler is installed at the rear stage of the high-pressure carbon dioxide gas bubbler. And an outlet for discharging carbon dioxide-dissolved water in which the carbon dioxide gas is dissolved in the solvent is formed at the upper portion of the container, and a granular filler is formed in the container. One or more dissolution tanks configured to be filled. It was configured to be. In this carbon dioxide gas dissolving device, it is possible to send a certain amount of finely bubbled undissolved carbon dioxide gas to the injection well by appropriately selecting the number of carbon dioxide gas thinning devices and the number of dissolution tanks.

  In the carbon dioxide gas dissolving apparatus, first, the dissolution tank is configured by filling a granular container in a sealed container, so that carbon dioxide gas (liquid or supercritical state) at a high concentration near the saturated concentration level in this dissolution tank. ) Can be dissolved in a solvent (seawater or water), and the specific gravity of carbon dioxide-dissolved water is greater than that of the surrounding groundwater, so that carbon dioxide can be stored and sequestered in the aquifer in a long-term and stable manner. Will be able to.

  In addition, by installing a high-pressure carbon dioxide gas bubbler in the previous stage of the dissolution tank, as shown in Example 2-1 described later, a high dissolution efficiency is realized by a synergistic effect with the dissolution tank. Is possible. As a result, the dissolution tank can be made compact and has a high processing capacity.

  On the other hand, in the underground storage system according to Case 1, even when the aquifer is located in the formation below the sea bottom away from the coastal area, the carbon dioxide dissolved water generated by the carbon dioxide dissolving device is supplied by a pipeline or the like. Since there is no need for long-distance transportation, it is possible to solve the problem that transportation costs increase due to friction loss during transportation and the economic efficiency deteriorates. Moreover, although the pipeline which conveys a carbon dioxide dissolved water receives the handling of a high pressure gas, since the pipeline for solvents does not receive this handling, the increase in transportation cost can be suppressed.

  In addition, since the carbon dioxide dissolving device is installed in the vicinity of the injection well, and the solvent pressure pump and the carbon dioxide dissolving device are connected by a pipeline, the aquifer is separated from the coastal area. When located in a subsurface formation, the temperature of the carbon dioxide gas dissolving apparatus and pipeline installed on the sea bottom is low temperature around 10 ° C., which is advantageous in dissolving carbon dioxide in a solvent. In other words, the amount of carbon dioxide dissolved in the solvent tends to increase at low temperatures, and the experiment reveals that the amount of carbon dioxide dissolved in the solvent is low. Therefore, the carbon dioxide gas dissolving apparatus can efficiently dissolve the carbon dioxide gas in the solvent.

  As the present invention according to claim 2, in the carbon dioxide gas dissolving device, undissolved carbon dioxide gas 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. And a carbon dioxide gas that separates the undissolved carbon dioxide gas separated into the intermediate flow path between the carbon dioxide gas compression device and the dissolution tank. A carbon dioxide underground storage system according to claim 1, which includes a pumping device.

  The invention described in claim 2 incorporates a separation tank as a modification of the first structural pattern of the carbon dioxide gas dissolving apparatus. As a result, for the total amount of carbon dioxide-dissolved water generated in the dissolution tank, the undissolved carbon dioxide content is separated in the separation tank, and the undissolved carbon dioxide content is returned to the dissolution tank to ensure that 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 3, is a carbon dioxide underground storage system for press-fitting into a groundwater aquifer in a state in which carbon dioxide gas is dissolved in a solvent, for storage and isolation,
A carbon dioxide gas compression device that compresses carbon dioxide gas to a liquid or supercritical state, and a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water,
A carbon dioxide gas inlet for injecting carbon dioxide gas sent from the carbon dioxide gas compressor and a solvent inlet for injecting a solvent sent from the solvent pressure pump are formed at the bottom of the sealed container. In addition, one or a plurality of discharge ports for discharging carbon dioxide-dissolved water in which the carbon dioxide gas is dissolved in the solvent are formed in the upper part of the container, and the container is filled with a granular filler. Separating the dissolution tank and the carbon dioxide dissolved water in a state where the dissolved carbon dioxide and carbon dioxide are dissolved at a saturated concentration with respect to the total amount of the carbon dioxide dissolved water installed and fed after the dissolution tank A separation tank, a carbon dioxide pumping apparatus for pumping the carbon dioxide separated in the separation tank, and an inside of a main flow line in which the carbon dioxide-dissolved water is flowed at a predetermined high flow rate after the carbon dioxide pump. In addition, pumping from the carbon dioxide pump A carbon dioxide gas supply line, or a carbon dioxide gas supply line pumped from the carbon dioxide gas pressure device so as to fit the mainstream pipe line, Including a high-pressure carbon dioxide gas refining device that forms pores on a wall surface of a pipe partitioning carbon dioxide gas and mixes the carbon dioxide gas while making the carbon dioxide gas fine by a shearing force generated by carbon dioxide-dissolved water flowing in the mainstream pipe. Install a carbon dioxide dissolving device,
In order to inject the generated carbon dioxide-dissolved water into the underground aquifer, it is configured by installing an injection well penetrating from the ground surface to the aquifer,
The carbon dioxide compression device and the solvent pressure pump are disposed on land apart from the aquifer, and the carbon dioxide dissolution device is disposed in the vicinity of the injection well. The carbon dioxide compression device, the solvent pressure pump, and carbon dioxide A carbon dioxide underground storage system is provided in which a melting apparatus is connected to each other by a pipeline.

  The invention according to claim 3 defines the second configuration pattern of the carbon dioxide dissolving apparatus used in the underground storage system according to case 1. In the second configuration pattern of the carbon dioxide gas dissolving device, the high-pressure carbon dioxide gas bubble forming device is incorporated in a pipe line extending from the dissolving tank to the injection well.

  As a fourth aspect of the present invention, a branching device for branching the carbon dioxide gas fed from the carbon dioxide pressure feeding device is disposed between the carbon dioxide pressure feeding device and the supply pipe, and The amount of the carbon dioxide gas that can be dissolved in the path from the fine foaming device to the aquifer is branched and pumped to the supply pipe, and the remaining amount of the carbon dioxide gas is returned to the dissolution tank. Thus, a carbon dioxide underground storage system according to claim 3 is provided.

  In the second aspect of the present invention, the carbon dioxide gas is reliably returned to the solvent (seawater or seawater) at the saturation concentration level by returning the undissolved carbon dioxide content to the dissolution tank with respect to the second configuration pattern of the carbon dioxide gas dissolving apparatus. It is possible to press into the ground in a state dissolved in water. In this carbon dioxide gas dissolving device, a certain amount of finely bubbled undissolved carbon dioxide gas is sent to the injection well by appropriately selecting the amount of undissolved carbon dioxide gas fed from the branching device to the fine bubble producing device. Is possible.

  As a fifth aspect of the present invention, the solvent pressure pump disposed on land far from the aquifer is for low pressure, and a high pressure pressure increasing pump is disposed in the front stage in the vicinity of the carbon dioxide gas dissolving device. The underground storage system of the carbon dioxide gas in any one of 1-4 is provided.

  The invention according to claim 5 defines the case 2 of the underground storage system according to the present invention. Specifically, a solvent compression pump installed on land far from the aquifer is used for low pressure, and a high pressure booster pump is disposed in the front stage near the carbon dioxide gas dissolving device. As a result, a low-pressure pipeline can be used as the solvent pipeline up to the vicinity of the carbon dioxide dissolving apparatus, and the equipment cost can be reduced. In the underground storage system according to case 2, both the first configuration pattern and the second configuration pattern of the carbon dioxide gas dissolving apparatus can be used.

  As the present invention according to claim 6, in place of disposing the solvent pump on land far from the aquifer, the solvent pump is installed in the vicinity of the carbon dioxide dissolving device, and the carbon dioxide compressor and the solvent pump are installed. The underground storage system of the carbon dioxide gas in any one of Claims 1-4 which connected the carbon dioxide gas dissolving device and the carbon dioxide melt | dissolution apparatus with the pipeline, respectively is provided.

  The invention described in claim 6 is the case 3 of the underground storage system according to the present invention. Specifically, the carbon dioxide compression device is installed on land far from the aquifer, the carbon dioxide dissolution device is located near the injection well, and the solvent pump is located near the carbon dioxide dissolution device. These carbon dioxide compression devices, solvent pressure pumps, and carbon dioxide dissolution devices are respectively connected by pipelines. As a result, the solvent pipeline can be shortened, and when the aquifer is located in the formation below the seabed away from the coastal area, the seawater is taken up at a low temperature around the solvent pump and used as a solvent. Thus, the carbon dioxide gas can be efficiently dissolved in the solvent in the carbon dioxide gas dissolving apparatus. In addition, in the case 3 of the underground storage system, both the first configuration pattern and the second configuration pattern of the carbon dioxide dissolving apparatus can be used.

  In the present invention according to claim 7, when the aquifer is located in a formation below the seabed, an offshore platform is constructed on the ocean near the aquifer, and at least the carbon dioxide gas dissolving device is installed on the offshore platform. A carbon dioxide underground storage system according to any one of claims 1 to 6 is provided.

  The invention described in claim 7 is the case 4 of the underground storage system according to the present invention. In Case 4, when the aquifer is located in the formation below the sea bottom, an offshore platform is constructed on the ocean near the aquifer, and at least a carbon dioxide gas dissolving device is disposed on the offshore platform. Thereby, maintenance management of a carbon dioxide gas dissolving device can be facilitated. In addition, in the case 4 of the underground storage system, both the first configuration pattern and the second configuration pattern of the carbon dioxide gas dissolving apparatus can be used.

In the present invention according to claim 8, the flow rate of the solvent and the pore diameter are set so that the Weber number (We) obtained by the following formula (1) is 10 or more. A carbon dioxide underground storage system according to any one of the above is provided.

  In the invention described in claim 8, according to Example 2-3 described later, when setting the flow rate of the solvent and the pore diameter of the pores, the Weber number (We) is set to 10 or more, whereby efficient and high throughput is achieved. It becomes possible to produce a high foaming efficiency with a fine foam.

  The present invention according to claim 9 is the carbon dioxide underground storage system according to any one of claims 1 to 8, wherein the granular filler is sand, crushed stone, Raschig ring, or saddle. Provided.

  In the invention according to the ninth aspect, as the granular filler 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 10, 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 of carbon dioxide gas according to any one of claims 1 to 9, wherein an optimum average particle diameter determined from the loss is provided.

  In the invention of claim 10, the granular filler is, for each type of filler, the amount of carbon dioxide dissolved based on the flow rates 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.

  As the present invention according to claim 11, in the melting tank, one or a plurality of rectifying plates in which a large number of apertures are 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 -10 is provided.

  In the invention described in claim 11, by providing the current plate, dissolution of carbon dioxide gas in the dissolution tank is promoted.

  As described above in detail, according to the present invention, in a state where carbon dioxide gas is dissolved in a solvent (seawater or water) at a high concentration near the saturation concentration level, carbon dioxide-dissolved water is injected into the aquifer and stored / isolated. A carbon dioxide underground storage system can be provided. Furthermore, carbon dioxide gas can be efficiently dissolved in a solvent, and a carbon dioxide underground storage system that suppresses an increase in transportation costs can be provided.

It is a key map of underground storage system 1A concerning case 1 of the present invention. It is a conceptual diagram (the 1) of the carbon dioxide dissolving apparatus 40A which concerns on a 1st structure pattern. It is a conceptual diagram (the 2) of the carbon dioxide dissolving apparatus 40A which concerns on a 1st structure pattern. It is a longitudinal cross-sectional view of the dissolution tank 4. It is a longitudinal cross-sectional view of the fine foaming apparatus 7A which concerns on a 1st form example. It is a longitudinal cross-sectional view of the fine foaming apparatus 7B which concerns on a 2nd example (the 1). It is a longitudinal cross-sectional view of the fine foaming apparatus 7C which concerns on a 2nd example (the 2). 3 is a longitudinal sectional view of a separation tank 6. FIG. It is a conceptual diagram of the carbon dioxide gas dissolving device 40B which concerns on a 2nd structure pattern. It is a longitudinal cross-sectional view of the dissolution tank 4. It is a conceptual diagram of the underground storage system 1B which concerns on the case 2. FIG. It is a conceptual diagram of 1 C of underground storage systems which concern on the case 3. FIG. It is a key map of underground storage system 1D concerning case 4. It is a conceptual diagram of the underground storage system 1E which concerns on case 5. FIG. It is a conceptual diagram of an experimental apparatus. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the particle size and salt water flow rate in the temperature of 29 degreeC in Example 1, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the particle size and salt water flow rate in the temperature of 33 degreeC in Example 1, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the pressure in 25 degreeC in Example 1, and the flow rate of salt water, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio and the amount of carbon dioxide dissolved when the pressure at a temperature of 29 ° C. and the salt water flow rate in Example 1 are changed. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the pressure in 33 degreeC in Example 1, and the flow rate of salt water, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the temperature in Example 1, and a carbon dioxide gas dissolution amount. 2 is a graph showing the relationship between the average particle diameter of fillers in Example 1 and the amount of carbon dioxide dissolved. It is a graph which shows a verification experiment result quantitatively about the melt | dissolution effect in the fine foaming apparatus 7 in Example 2-1, and the melt | dissolution effect in the dissolution tank 4. Graph showing the relationship between the overall capacity coefficient K _{x a} water cross section molar flow rate in Example 2-2; FIG. It is a graph (part 2) showing the relationship between overall capacity coefficient K _{x a} water cross section molar flow rate in Example 2-2. Graph showing the relationship between the overall capacity coefficient K _{x a} water cross section molar flow rate in Example 2-2 is a third. Is a graph showing the relationship between the overall capacity coefficient ratio _{K x a (B) / K} x a (NB) and Weber number We in Example 2-3.

  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 into a solvent (seawater and / or water) at a high concentration near the saturation concentration level. In this state, it is contained in the underground aquifer, and it is for long-term and stable storage and isolation.

  In particular, in the present invention, when the aquifer is located in a stratum below the sea bottom away from the coastal area, when the carbon dioxide emission source and the ground surface immediately above the aquifer are long distance, etc. An underground storage system advantageous in dissolving carbon dioxide gas is provided.

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, it is desirable to maintain a high pressure state of 8 MPa or more. In general, in an aquifer, if a groundwater pressure of 5 MPa or more can be secured, it can be efficiently stored.

  The underground storage system 1 according to the present invention can be classified into the following cases 1 to 4 depending on conditions of the local site to be applied.

[Case 1]
As shown in FIG. 1, the underground storage system 1 </ b> A according to the case 1 compresses and conveys a carbon dioxide gas compression device 2 that compresses carbon dioxide gas to a liquid or supercritical state, and seawater and / or a solvent composed of water. The pumping pump 3, the compressed carbon dioxide gas and the solvent are injected, the carbon dioxide gas dissolving device 40 that dissolves the carbon dioxide gas in the solvent to form carbon dioxide-dissolved water, and the generated carbon dioxide-dissolved water is underground. And the injection well 5 penetrating from the ground surface pressed into the aquifer to the aquifer.

  In this case 1, the carbon dioxide gas compressing device 2 and the solvent pumping pump 3 are disposed on land apart from the aquifer, and the carbon dioxide dissolving device 40 is disposed in the vicinity of the injection well 5. Further, the carbon dioxide compression device 2 and the carbon dioxide dissolving device 40 are connected by a carbon dioxide pipeline 41, and the solvent pump 3 and the carbon dioxide dissolving device 40 are connected by a solvent pipeline 42. Yes. FIG. 1 is a diagram showing a case where the aquifer storage site is located in a formation below the sea bottom. In this case, the carbon dioxide gas dissolving device 40 is installed on the sea bottom near the injection well 5. The carbon dioxide pipeline 41 and the solvent pipeline 42 are disposed on the sea bottom and connected to the carbon dioxide dissolving device 40.

  The carbon dioxide gas dissolving device 40 can be either the following first configuration pattern 40A or second configuration pattern 40B.

(Carbon dioxide dissolution apparatus 40A according to the first configuration pattern)
As shown in FIG. 2, the carbon dioxide gas dissolving device 40 </ b> A according to the first configuration pattern is a high-pressure carbon dioxide gas foaming device in which the liquid or the carbon dioxide gas compressed to the supercritical state is foamed and mixed into the solvent. A device 7 (hereinafter simply referred to as a fine foaming device) and a solvent mixed with carbon dioxide gas that has been made fine by the fine foaming device 7 are injected, and the carbon dioxide gas is dissolved in the solvent to dissolve the carbon dioxide gas. A plurality of dissolution tanks 4 as water are arranged side by side. In the present embodiment, a plurality of the dissolution tanks 4 and the fine foaming devices 7 are installed in order to promote the dissolution of carbon dioxide gas, but the number may be set according to the processing capacity.

  As shown in FIG. 5 to FIG. 7, the fine foaming device 7 makes carbon dioxide gas by increasing the contact area by finely foaming carbon dioxide gas compressed into a liquid or supercritical state and mixing it into a solvent. It is for promoting dissolution of the. This foaming device 7 is used alone or preferably in combination with the dissolution tank 4 as in the examples described later. The said fine foaming apparatus 7 can be made into the following 1st example 7A or 2nd example 7B, 7C.

  As shown in FIG. 5, in the case of the carbon dioxide gas dissolving apparatus 40A according to the first configuration pattern, the fine foaming device 7A according to the first embodiment uses seawater and / or water as a solvent, and a second configuration described later. In the case of the carbon dioxide gas dissolving device 40B according to the pattern, carbon dioxide gas dissolved water is used as a solvent, and the carbon dioxide gas supply pipe 31 for fitting the solvent to the main flow line 30 in which these solvents are flowed at a predetermined high flow rate Is formed on the wall surface of the pipe line that divides and separates the solvent and carbon dioxide gas, in the illustrated example, the pipe wall face of the main flow pipe line 30, and shearing of the solvent flowing through the main flow pipe line 30 is formed. The carbon dioxide gas compressed to a liquid or supercritical state by force is mixed while being finely bubbled.

  When a plurality of the pores 30a are arranged, as shown in the figure, it is desirable that the pores 30a are arranged on the wall surface of the mainstream pipe 30 in a uniform manner in the circumferential direction and in a multistage arrangement with an interval in the axial direction. .

The flow rate of the solvent and the pore diameter of the pores 30a are preferably set so that the Weber number (We) obtained by the following formula (1) is 10 or more according to Example 2-3 described later. However, the flow rate of the carbon dioxide gas from the pore is required to be 8 × 10 ⁻² m / s or more.

  The diameter of the fine carbon dioxide gas is about 0.05 to 0.2 mm, and it is not necessary to make it fine up to the micro level (10 to several tens of μm).

  As shown in FIGS. 6 and 7, the fine foaming devices 7 </ b> B and 7 </ b> C according to the second embodiment include a carbon dioxide gas supply line 31 inside the main flow line 30 in which the solvent is flowed at a predetermined high flow rate. Is formed on the wall surface of the pipe line that divides and separates the solvent and the carbon dioxide gas, in the illustrated example, the pipe wall surface of the carbon dioxide supply pipe line 31, and the solvent flowing through the main flow line 30. The carbon dioxide gas compressed to a liquid or supercritical state by the shearing force is mixed while being finely bubbled.

  The foaming device 7 shown in FIG. 4 is the foaming device according to the second embodiment, and is installed in the lower part of each dissolution tank 4 to transfer the solvent pumped from the solvent pumping pump 3 to a predetermined height. A carbon dioxide gas supply pipe 31 for supplying the carbon dioxide gas compressed by the carbon dioxide gas compression device 2 is disposed inside the main flow pipe 30 that flows at a flow velocity, and the carbon dioxide gas supply for partitioning the solvent and the carbon dioxide gas is provided. Fine pores 31a, 31a ... are formed on the pipeline wall surface of the pipeline 31 and mixed with carbon dioxide gas compressed to a liquid or supercritical state by the shearing force of the solvent flowing through the mainstream pipeline 30 while making it fine. .

  As shown in FIG. 4, the dissolution tank 4 has an injection port 9 into which a solvent mixed with carbon dioxide gas finely bubbled by the fine bubbler 7 is injected at the bottom of a sealed container 10. A discharge port 13 through which the carbon dioxide dissolved water is discharged is formed in the upper part of the container 10, and a perforated plate 14 that partitions the inside of the container 10 vertically in the lower and upper parts of the container 10, respectively. , 14 are disposed, and a granular filler 16 is filled between the perforated plates 14, 14. A mesh plate 15 is installed at the inlet 9.

  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, the following two relations (1) and (2) with respect to the average particle size of the filler were experimentally obtained, and then the pressure loss allowed in the dissolution tank (dissolution tank) The difference in pressure between the injection port and the discharge port) is selected as the optimum average particle size with an average particle size that maximizes the amount of dissolution.
(1) The relationship of the amount of carbon dioxide dissolved with respect to the average particle diameter of the filler in the predetermined carbon dioxide and solvent flow rates 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 dissolved amount of carbon dioxide gas. 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. By using the filler 16 having the optimum average particle diameter, the carbon dioxide gas is efficiently dissolved.

  As shown in FIG. 4, 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. The carbon dioxide gas and the solvent pumped into the container 10 from the injection port 9 enter the filling region of the filler 16 evenly from the mesh plate 15. 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. By this action, when the upper porous plate 14 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 14 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.

  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 addition, as a modification of the first configuration pattern, as shown in FIG. 3, 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 is provided for separating undissolved carbon dioxide gas and carbon dioxide-dissolved water in a state where carbon dioxide gas is dissolved at a saturated concentration, and the separated undissolved carbon dioxide gas is separated from the former stage of the fine foaming device 7. A configuration in which a carbon dioxide gas feeding device 8 for returning to the carbon dioxide pipeline 41 can be provided.

  Saturation is achieved by separating undissolved carbon dioxide in the separation tank 6 and returning the undissolved carbon dioxide to the dissolution tank 4 for the total amount of carbon dioxide dissolved water discharged from the dissolution tank 4. It becomes possible to press-fit into the ground with carbon dioxide gas dissolved in a solvent (seawater or water) at a concentration level. Therefore, this carbon dioxide-dissolved water does not contain undissolved carbon dioxide, and has a higher specific gravity than the groundwater around the aquifer. In addition, it can be stably stored and isolated in the aquifer.

  As shown in FIG. 8, the separation tank 6 is an inflow connected to a flow path of carbon dioxide dissolved water passing through the dissolution tank 4, standing in a sealed container 20 at a predetermined height from the lower surface. 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.

  In the modification of 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. The undissolved carbon dioxide contained in the carbon dioxide-dissolved water discharged from 4... 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.

(Carbon dioxide melting device 40B according to the second configuration pattern)
Next, based on FIG.9 and FIG.10, the carbon dioxide melt | dissolution apparatus 40B which concerns on a 2nd structure pattern is described.

  As shown in FIG. 9, the present carbon dioxide dissolving device 40 </ b> B is composed of carbon dioxide compressed to a liquid or supercritical state by the carbon dioxide compression device 2 and seawater and / or water compressed and conveyed by the pressure pump 3. A plurality of dissolution tanks 4, 4..., In which a solvent is injected and the carbon dioxide gas is dissolved in the solvent to form carbon dioxide-dissolved water, and the carbon dioxide gas that is installed and fed after the dissolution tanks 4, 4. Separation tank 6 that separates undissolved carbon dioxide gas and carbon dioxide-dissolved water in a state in which carbon dioxide gas is dissolved at a saturated concentration, and carbon dioxide gas separated in the separation tank 6 by pressure with respect to the total amount of dissolved water The carbon dioxide pumping device 8 and the carbon dioxide pumped from the carbon dioxide pumping device 8 into the main stream line 30 in which the carbon dioxide-dissolved water is flowed at a predetermined high flow rate after the carbon dioxide pumping device 8. Supply line 31 to which gas is supplied Or a main pipe line 30 and a supply pipe line 31 to which the carbon dioxide gas fed from the carbon dioxide gas feeding device 8 is supplied, and the carbon dioxide-dissolved water, the carbon dioxide gas, Is mainly composed of a fine foaming device 7 which forms pores on the wall surface of the pipe line partitioning the gas and mixes the carbon dioxide gas while making it fine by the shearing force of the carbon dioxide dissolved water flowing through the main flow line 30 It is.

  As shown in FIG. 10, the dissolution tank 4 includes a carbon dioxide gas inlet 11 through which the 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.

  Further, in the present carbon dioxide gas dissolving device 40B, as shown in FIG. 9, the carbon dioxide gas fed from the carbon dioxide gas feeding device 8 is branched between the carbon dioxide gas feeding device 8 and the supply conduit 30. A branching device 32 is arranged, and the branching device 32 branches an amount of the carbon dioxide gas that can be dissolved in the path from the fine foaming device 7 to the aquifer and pumps it to the supply pipe 30. However, the remaining amount of the carbon dioxide gas may be returned to the dissolution tanks 4, 4.

  In the underground storage system 1A according to the case 1 having the above-described configuration, the carbon dioxide is compressed by the on-shore carbon dioxide compression device 2 and pressurized to a required pressure, and then the aquifer is formed by the carbon dioxide pipeline 41. It is transported to a nearby carbon dioxide gas dissolving device 40. In addition, a solvent such as seawater and / or water is boosted to a required pressure by the solvent pump 3 on land, and then transported to the carbon dioxide gas dissolving device 40 by the solvent pipeline 42. Thereafter, the carbon dioxide gas and the solvent are converted into carbon dioxide-dissolved water by the dissolution tank 4 and the fine foaming device 7 incorporated in the carbon dioxide-dissolving device 40, and then stored in the aquifer through the injection well 5. .

  In this case 1, since it is not necessary to transport the carbon dioxide-dissolved water generated by the carbon dioxide-dissolving device 40 over a long distance by a pipeline, the transportation cost does not increase due to friction loss during transportation. In the case of a pipeline that transports carbon dioxide-dissolved water, the high-pressure gas is handled. However, the solvent pipeline 42 does not receive this handling, so that an increase in transportation cost can be suppressed.

  Further, the carbon dioxide gas dissolving device 40 is installed on the sea bottom, and the carbon dioxide gas pipeline 41 and the solvent pipeline 42 connected to the carbon dioxide gas dissolving apparatus 40 are disposed in the vicinity of the sea bottom. Carbon dioxide is stable at around 10 ° C, which is equivalent to seawater temperature. Here, the amount of carbon dioxide dissolved in the solvent tends to increase as the temperature decreases as a result of the dissolution experiment described in detail later (see the relative low temperature conditions of 15 ° C. to 20 ° C. in FIG. 21). Therefore, in this case 1, since the pipelines 41 and 42 and the carbon dioxide gas dissolving device 40 are arranged in a low-temperature atmosphere, it is advantageous for dissolving the carbon dioxide gas.

  In addition, since the carbon dioxide gas compression device 2 and the solvent pressure pump 3 are provided on land, it is not necessary to install a power supply cable in the sea, and the equipment cost and maintenance / inspection cost can be reduced.

[Case 2]
As shown in FIG. 11, the underground storage system 1 </ b> B according to Case 2 uses a low pressure solvent pump pump 3 </ b> A installed on land far from the aquifer, and has a high pressure in the front stage in the vicinity of the carbon dioxide gas dissolving device 40. The pressure increasing pump 3B is disposed, and the solvent pressure pump 3A and the pressure increasing pump 3B are connected by a low pressure solvent pipeline 42A, and the pressure increasing pump 3B and the carbon dioxide gas dissolving device 40 are connected to each other. They are different from the above case 1 in that they are connected by a high-pressure solvent pipeline 42B.

  The low pressure solvent pressure pump 3A only needs to generate a pressure sufficient to pump the solvent to the pressure increasing pump 3B, and the high pressure pressure increasing pump 3B generates carbon dioxide dissolved water in the carbon dioxide dissolving device 40. It is for pressurizing to the pressure required for this.

  When the aquifer is located in the formation below the bottom of the sea as in the illustrated example, it is preferable that the booster pump 3B is installed on the bottom of the sea like the carbon dioxide gas dissolving device 40. In addition, a power supply cable is provided from the land to the pressure increasing pump 3B installed on the sea bottom.

  In the underground storage system 1B, the carbon dioxide gas is compressed by the on-shore carbon dioxide gas compressing device 2 and pressurized to a required pressure, and then passes through the carbon dioxide pipeline 41 to the carbon dioxide dissolving device 40 near the aquifer. Transported. Also, a solvent such as seawater and / or water is supplied to the pressure increasing pump 3B installed in the vicinity of the carbon dioxide gas dissolving device 40 by the low-pressure solvent pipeline 42A under the low-pressure condition by the low-pressure solvent pressure-feeding pump 3A on land. Transported. Thereafter, the pressure is increased to a required pressure by a pressure increasing pump, and transported to the carbon dioxide gas dissolving device 40 through the high-pressure solvent pipeline 42B. Thereafter, the carbon dioxide gas and the solvent are converted into carbon dioxide-dissolved water by the dissolution tank 4 and the fine foaming device 7 incorporated in the carbon dioxide dissolution apparatus 40, and then stored in the aquifer through the injection well 5. . The carbon dioxide gas dissolving device 40 can be either the first configuration pattern 40A or the second configuration pattern 40B, similarly to the underground storage system 1A according to the case 1.

  In this case 2, since the low-pressure solvent pipeline 42A can be used up to the pressure increasing pump 3B in the vicinity of the carbon dioxide gas dissolving device 40, the equipment cost can be reduced.

[Case 3]
As shown in FIG. 12, the underground storage system 1 </ b> C according to the case 3 is installed in the vicinity of the carbon dioxide dissolving device 40 instead of disposing the solvent pump 3 on the land far from the aquifer. This is different from Case 1 above. Here, when the aquifer is located in the formation below the sea bottom as in the illustrated example, seawater around the sea bottom where the solvent pump 3 is installed can be taken as a solvent. In addition, the solvent may be used by pumping up groundwater or receiving supply of groundwater pumped up in other projects. In addition, a cable for supplying power from the land is provided for the solvent pump 3 installed on the bottom of the sea.

  In the underground storage system 1C, the carbon dioxide gas is compressed by the on-shore carbon dioxide gas compressing device 2 and pressurized to a required pressure, and then passes through the carbon dioxide pipeline 41 to the carbon dioxide dissolving device 40 near the aquifer. Transported. The solvent sucked in by taking seawater in the vicinity is raised to a required pressure by the solvent pressure pump 3, and then sent to the adjacent carbon dioxide dissolving device 40 through the solvent pipeline 42. Thereafter, the carbon dioxide gas and the solvent are converted into carbon dioxide-dissolved water by the dissolution tank 4 and the fine foaming device 7 incorporated in the carbon dioxide-dissolving device 40, and then stored in the aquifer through the injection well 5. .

  In this case 3, the solvent pipeline 42 can be shortened, and when the aquifer is located under the sea bottom away from the coastal area, the solvent pump 3 can take in stable seawater at a low temperature in the surrounding area. Therefore, carbon dioxide gas can be efficiently dissolved in the carbon dioxide gas dissolving device 40.

[Case 4]
In the underground storage system 1D according to the case 4, as shown in FIG. 13, when the aquifer is located in the formation below the sea floor, the offshore platform 43 is constructed on the ocean near the aquifer, The case 1 is different from the case 1 in that at least the carbon dioxide dissolving device 40 is disposed on the offshore platform 43. Further, in the illustrated example, the solvent pressure pump 3 is disposed in the sea near the carbon dioxide gas dissolving device 40, and is different from the case 1 in that the surrounding sea water is taken as a solvent and is pumped to the carbon dioxide gas dissolving device 40. To do. The solvent pump 3 may be installed on the offshore platform 43, and groundwater or the like may be used as a solvent.

  The construction of the offshore platform 43 in the present case 4 and the disposition of the carbon dioxide dissolving device 40 on the offshore platform 43 can be similarly applied to the underground storage system 1 of the above cases 1 to 3.

  In the underground storage system 1D, the carbon dioxide gas is compressed by the on-shore carbon dioxide gas compression device 2 and pressurized to a required pressure, and then passed through the carbon dioxide gas pipeline 41 to the carbon dioxide gas dissolving device 40 near the aquifer. Transported. In addition, the solvent sucked in, for example, by taking in the surrounding seawater is increased to a required pressure by the solvent pressure pump 3 installed in the sea, and then sent to the carbon dioxide dissolving device 40 through the solvent pipeline 42. It is done. Thereafter, the carbon dioxide gas and the solvent are converted into carbon dioxide-dissolved water by the dissolution tank 4 and the fine foaming device 7 incorporated in the carbon dioxide-dissolving device 40, and then stored in the aquifer through the injection well 5. .

  In the case 4, at least the carbon dioxide gas dissolving device 40 is disposed on the offshore platform 43, so that the maintenance and management of the carbon dioxide gas dissolving device 40 can be facilitated. Further, by taking water from a water depth that is optimal for dissolving carbon dioxide gas, the dissolution concentration and dissolution rate of carbon dioxide gas can be increased.

[Case 5]
In the underground storage system 1E according to the case 5, as shown in FIG. 14, when the carbon dioxide emission source and the carbon dioxide aquifer are separated on land, The storage system 1 is adopted. In the case of the illustrated example, the carbon dioxide gas is compressed by the carbon dioxide compression device 2 installed near the discharge source, and after being pressurized to the required pressure, is installed on land near the aquifer through the carbon dioxide pipeline 41. The carbon dioxide gas dissolving device 40 is transported. The solvent is secured by taking the river water in the vicinity of the storage site, pumping the ground water or receiving the supply of ground water pumped by another project, etc., and is required by the solvent pump 3 installed near the storage site. And then sent to the carbon dioxide dissolving device 40 through the solvent pipeline 42. Thereafter, the carbon dioxide gas fed through each pipeline is dissolved in the solvent by the dissolution tank 4 and the fine foaming device 7 incorporated in the carbon dioxide gas dissolving device 40, and then the aquifer from the land surface on land. It is stored in the aquifer through the injection well 5 penetrating to the formation.

  In order to verify the state of carbon dioxide dissolution by the underground storage system 1, a carbon dioxide dissolution experiment was performed using the experimental apparatus shown in FIG. In addition, the fine foaming apparatus 7 was installed in the case with the fine foaming apparatus of Example 2 mentioned later.

  The experimental apparatus pressurizes the carbon dioxide gas in the carbon dioxide gas cylinder 45 by the carbon dioxide compression apparatus 2 and injects it into the dissolution tank 4, and pressurizes the salt water in the salt water tank 46 by the solvent pump 3 and injects it into the dissolution tank 4 for dissolution. Carbon dioxide dissolved in the tank 4 is sampled, and the carbon dioxide dissolved water after the carbon dioxide dissolved water is separated from the undissolved carbon dioxide in the separation tank 6 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.

  16 and 17 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 flow rate of salt water at each temperature and the particle size of the filler 16 are changed. 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.

  18 to 20 are graphs showing the relationship between the weight ratio and the amount of dissolved carbon dioxide gas when the brine 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. 21 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. Further, it was confirmed that the dissolution of carbon dioxide gas was promoted at a relatively low temperature condition of 15 ° C. to 20 ° C.

  FIG. 22 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.

(Example 2-1)
In Example 2-1, an experiment for quantitatively verifying the dissolution effect in the fine foaming device 7 and the dissolution effect in the dissolution tank 4 by the underground storage system 1 was performed.

  Experiments are as follows: condition 1: no filler in dissolution tank 4 and no finer 7, condition 2: no filler in dissolution tank 4 and finer 7, condition 3: with filler in dissolution tank 4 and (1) Test pressure: 15 MPa, test temperature: 29 ° C., (carbon dioxide / brine water) weight ratio: about 8%, (2) Test pressure: 15 MPa, test temperature: 33 A dissolution test was conducted on two types of C, and (carbon dioxide / salt water) weight ratio: about 8%.

  The result is shown in FIG. From FIG. 23, it can be seen that the dissolution of carbon dioxide gas is considerably promoted by the fine foaming device 7 alone, and further that the dissolution is further promoted by combining the fine foaming device 7 and the dissolution tank 4. I was able to prove.

(Example 2-2)
In the present Example 2-2, verification experiment of the melt | dissolution promotion effect by the said bubble reduction apparatus 7 was conducted.

In general, it has been found that the relationship of the following equation (2) holds between the amount of carbon dioxide dissolved and the container height Z of the dissolution tank.

The height Z of the container required for dissolution is dependent on overall capacity coefficient K _{X a,} and the overall capacity coefficient K _{X a} as an index representing the dissolution efficiency. The experiment is for each case without a foaming device and with a foaming device. (1) Test pressure: 15 MPa, Test temperature: 29 ° C, (Carbon dioxide / salt water) Weight ratio: About 8%, (2) Test Pressure: 15 MPa, test temperature: 29 ° C., (carbon dioxide / salt water) weight ratio: about 10%, (3) test pressure: 15 MPa, test temperature: 33 ° C., (carbon dioxide / salt water) weight ratio: about 8% As shown in FIGS. 24 to 26, three types of tests were conducted. The vertical axis represents the overall capacity coefficient K _x a (mol / m ³ s), and the horizontal axis represents the cross-sectional molar flow velocity (mol / (m ² ) of water.・ The graph of s)) was obtained. According to the graphs of FIGS. 24 to 26, in the region where the cross-sectional molar flow velocity of water (mol / (m ² · s)) is high, the case with the foaming device is compared with the case without the foaming device. Thus, it has been found that the overall capacity coefficient K _x a is 1.5 times or more.

(Example 2-3)
The experimental results of Example 2-2 were rearranged using the Weber number We shown in the following formula (1), and as shown in FIG. 27, the vertical axis represents the overall capacity coefficient ratio K _x a (B) / K _x a (NB) [where K _x a (B): overall capacity coefficient with a finer, K _x a (NB): overall capacity without a finer], the horizontal axis is the Weber coefficient A graph of We was obtained.

From FIG. 27, it was found that the dissolution efficiency due to fine foaming was high in the region where the Weber number We was 10 or more. Therefore, in the fine foaming device 7, the solvent flow rate and the pore diameter of the pores 30a (31a) are preferably set so that the Weber number (We) is 10 or more. However, according to the same experiment, the flow rate of carbon dioxide from the pores is 8 × 10 ⁻² m / s or more.

[Other examples]
(1) In the above embodiment, seawater and / or water is used as a solvent as it is, but when the groundwater is pumped up as a solvent or the groundwater pumped by another project is supplied, the temperature of the groundwater is Expected to be high. For this reason, when using such groundwater as a solvent, it is possible to perform heat exchange with relatively low-temperature seawater at the bottom of the sea to lower the temperature of the groundwater.

  1. 1A to 1E: underground storage system, 2 ... carbon dioxide compression device, 3 ... solvent pump, 4 ... dissolution tank, 5 ... injection well, 6 ... separation tank, 7 ... fine foaming device, 8 ... carbon dioxide gas Pressure feeding device, 10 ... container, 11 ... carbon dioxide gas inlet, 12 ... solvent inlet, 13 ... outlet, 14 ... perforated plate, 15 ... mesh plate, 16 ... filler, 19 ... current plate, 20 ... container, 21 Inflow pipe, 22 ... Undissolved carbon dioxide gas outlet, 23 ... Carbon dioxide gas dissolved water outlet, 30 ... Mainstream pipe, 31 ... Carbon dioxide supply pipe, 30a, 31a ... Fine pore, 32 ... Branching device, 40 40A and 40B ... carbon dioxide gas dissolving device, 41 ... carbon dioxide pipeline, 42 ... solvent pipeline, 43 ... offshore platform

Claims (11)

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, and a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water,
The carbon dioxide gas supply line is disposed inside the main flow line through which the solvent flows at a predetermined high flow rate, or the carbon dioxide gas supply line that externally fits the main flow line is disposed, A high-pressure carbon dioxide gas refining device that forms pores in the wall surface of the pipe line that partitions the solvent and carbon dioxide gas, and mixes the carbon dioxide gas while making the carbon dioxide gas fine by the shearing force of the solvent flowing through the main flow line, and the high pressure An inlet for the solvent mixed with the carbon dioxide gas is formed in the lower part of the sealed container installed in the latter stage of the carbon dioxide gas bubbler for the use, and the solvent is formed in the upper part of the container. A carbon dioxide gas dissolving device including one or a plurality of dissolution tanks formed with a discharge port through which carbon dioxide dissolved water in which the carbon dioxide gas is dissolved is discharged, and filled with a granular filler in the container Install
It is constructed by installing an injection well penetrating from the ground surface to the aquifer in order to press-fit carbon dioxide dissolved water discharged from the dissolution tank into the underground aquifer,
The carbon dioxide compression device and the solvent pressure pump are disposed on land apart from the aquifer, and the carbon dioxide dissolution device is disposed in the vicinity of the injection well. The carbon dioxide compression device, the solvent pressure pump, and carbon dioxide A carbon dioxide underground storage system, characterized in that each melting apparatus is connected by a pipeline.   In the carbon dioxide gas dissolving device, undissolved carbon dioxide and carbon dioxide dissolve 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. 2. A separation tank for separating the carbon dioxide-dissolved water in a state in which the carbon dioxide gas is dissolved, and a carbon dioxide pressure feeding device for returning the separated undissolved carbon dioxide gas to an intermediate flow path between the carbon dioxide compression apparatus and the dissolution tank. The carbon dioxide underground storage system described. 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, and a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water,
A carbon dioxide gas inlet for injecting carbon dioxide gas sent from the carbon dioxide gas compressor and a solvent inlet for injecting a solvent sent from the solvent pressure pump are formed at the bottom of the sealed container. In addition, one or a plurality of discharge ports for discharging carbon dioxide-dissolved water in which the carbon dioxide gas is dissolved in the solvent are formed in the upper part of the container, and the container is filled with a granular filler. Separating the dissolution tank and the carbon dioxide dissolved water in a state where the dissolved carbon dioxide and carbon dioxide are dissolved at a saturated concentration with respect to the total amount of the carbon dioxide dissolved water installed and fed after the dissolution tank A separation tank, a carbon dioxide pumping apparatus for pumping the carbon dioxide separated in the separation tank, and an inside of a main flow line in which the carbon dioxide-dissolved water is flowed at a predetermined high flow rate after the carbon dioxide pump. In addition, pumping from the carbon dioxide pump A carbon dioxide gas supply line, or a carbon dioxide gas supply line pumped from the carbon dioxide gas pressure device so as to fit the mainstream pipe line, Including a high-pressure carbon dioxide gas refining device that forms pores on a wall surface of a pipe partitioning carbon dioxide gas and mixes the carbon dioxide gas while making the carbon dioxide gas fine by a shearing force generated by carbon dioxide-dissolved water flowing in the mainstream pipe Install a carbon dioxide dissolving device,
In order to inject the generated carbon dioxide-dissolved water into the underground aquifer, it is configured by installing an injection well penetrating from the ground surface to the aquifer,
The carbon dioxide compression device and the solvent pressure pump are disposed on land apart from the aquifer, and the carbon dioxide dissolution device is disposed in the vicinity of the injection well. The carbon dioxide compression device, the solvent pressure pump, and carbon dioxide A carbon dioxide underground storage system, characterized in that each melting apparatus is connected by a pipeline.   A branching device for branching the carbon dioxide pumped from the carbon dioxide pumping device is disposed between the carbon dioxide pumping device and the supply pipe line, and the fine bubbles of the carbon dioxide gas in the branching device are arranged. The amount which can be melt | dissolved by the path | route from a gasification apparatus to the aquifer is branched and pumped to the supply pipe line, and the remaining amount of the carbon dioxide gas is returned to the dissolution tank. Carbon dioxide underground storage system.   5. The carbonic acid pump according to claim 1, wherein a solvent pressure pump disposed on land far from the aquifer is for low pressure, and a high pressure pressure increasing pump is disposed in a front stage near the carbon dioxide dissolving device. Gas underground storage system.   Instead of placing the solvent pressure pump on land far from the aquifer, the solvent pressure pump is installed in the vicinity of the carbon dioxide gas dissolving device, and the carbon dioxide gas compression device, the solvent pressure pump, and the carbon dioxide gas dissolving device are piped respectively. The underground storage system of the carbon dioxide gas in any one of Claims 1-4 connected with the line.   In the case where the aquifer is located in a formation below the seabed, an offshore platform is constructed on the ocean near the aquifer, and at least the carbon dioxide dissolving device is disposed on the offshore platform. 6. The underground storage system for carbon dioxide gas according to any one of 6 above. The carbon dioxide gas ground according to any one of claims 1 to 7, wherein the flow rate of the solvent and the pore diameter of the pores are set so that the Weber number (We) obtained by the following formula (1) is 10 or more. Medium storage system.

  The carbon dioxide underground storage system according to any one of claims 1 to 8, 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 carbon dioxide underground storage system according to any one of claims 1 to 9, wherein the particle size is a particle size.   The carbon dioxide gas according to any one of claims 1 to 10, 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.

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