Radioactive waste water-based gas hydrate generator, storage system, and storage method

Abstract

The present invention relates to a radioactive wastewater-based gas hydrate generating device, a storage system, and a storage method, and more specifically, to a radioactive wastewater-based gas hydrate generating device, a storage system, and a storage method comprising a reactor disposed on the seabed and in which gas hydrate is generated, wherein radioactive wastewater is disposed on the lower side inside the reactor and liquefied gas is disposed on the upper side of the radioactive wastewater, and gas hydrate is generated at the interface between the radioactive wastewater and the liquefied gas.

Description

Technology Field

[0001] The present invention relates to a radioactive wastewater-based gas hydrate generating device, a storage system, and a storage method, and more specifically, to a radioactive wastewater-based gas hydrate generating device, a storage system, and a storage method capable of simultaneously sequestering radioactive wastewater, such as deuterium water or tritium water, and greenhouse gases such as carbon dioxide. Background Technology

[0002] Gas hydrates are crystalline solid materials formed when water and gas meet in a low-temperature, high-pressure environment. They can stably store large amounts of gas molecules, and natural gas is deposited in the form of hydrates in the deep sea and permafrost. The thermodynamic stability range and selectivity vary depending on the type of gas molecule, and active research is being conducted on this topic as it can be utilized in the fields of gas separation and storage.

[0003] Meanwhile, greenhouse gas emission regulations have been strengthened since the Kyoto Protocol, which stipulates greenhouse gas reduction obligations to solve the problem of global warming, entered into force in 2005.

[0004] Accordingly, while numerous technologies for reducing greenhouse gases have been proposed, there is a problem in that it is difficult to achieve short- to medium-term reduction targets solely through the development of alternative energy and increased energy efficiency, given the domestic industrial structure characterized by energy consumption.

[0005] As a result, carbon capture and storage (CCS) technology is being developed. Carbon capture and storage technology is expected to contribute to reducing 20 to 28% of the global carbon dioxide reduction (32 Gt).

[0006] One carbon dioxide storage technology that has recently garnered attention is the method using carbon dioxide hydrate.

[0007] Carbon dioxide hydrate is a stable crystal formed when carbon dioxide molecules are physically trapped within a cavity formed by water molecules under high pressure of about 10 bar or more and low temperature of about 10°C or less. It is formed when gas molecules, which are hydrate-forming or guest molecules, are trapped within the solid lattice of water molecules, which are the host molecules that form hydrogen bonds. Although it looks similar to ice, its crystal structure is known to have three main forms depending on the size and shape of the object: structure I (46 H2O), structure II (136 H2O), and structure H (34 H2O).

[0008] Hydrate structures are characterized by their ability to store target molecules at extremely high densities. For reference, in the case of carbon dioxide hydrate, 1 m 3 Approximately 180 m of hydrate at room temperature and pressure 3 , 330 kg of carbon dioxide can be captured. Therefore, technology can be utilized to inject and sequester large amounts of carbon dioxide into the ocean floor in a low-temperature environment using carbon dioxide hydrate.

[0009] Meanwhile, tritium is a radioactive substance that emits beta rays with a half-life of 12.5 years and exists in forms such as T2O; it is not removed at nuclear power plants but is released in a diluted form. It is the only radioactive substance that was not removed and was stored after the Fukushima nuclear accident.

[0010] Since tritium, a radioactive substance that emits low-energy beta rays, exists in the air in a vapor (moisture) state, it can enter the body through the respiration of workers or via the skin. As tritium absorbed into the human body in this manner can have fatal effects on workers, research is urgently needed on measures to isolate radioactive wastewater, such as tritium water. The problem to be solved

[0011] The technical problem that the present invention aims to solve is to provide a radioactive wastewater-based gas hydrate generating device capable of generating gas hydrate using radioactive wastewater containing tritium.

[0012] In addition, the technical problem that the present invention aims to solve is to provide a radioactive wastewater-based gas hydrate storage system and a storage method that can safely store gas hydrates generated using radioactive wastewater in the marine subsurface.

[0013] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by a person skilled in the art from the description below. means of solving the problem

[0014] According to embodiments of the present invention for achieving the above-mentioned objectives, a radioactive wastewater-based gas hydrate generating device is provided, comprising a reactor disposed on the seabed and in which gas hydrate is generated, wherein radioactive wastewater is disposed on the lower side inside the reactor and liquefied gas is disposed on the upper side of the radioactive wastewater, and gas hydrate is generated at the interface between the radioactive wastewater and the liquefied gas.

[0015] Here, the reactor may be cylindrical in shape having a specific length and diameter, with one end positioned toward the ocean surface and the other end positioned toward the ocean depth.

[0016] And, the above liquefied gas may include liquefied carbon dioxide, and the above gas hydrate may include carbon dioxide hydrate.

[0017] In addition, the above radioactive wastewater may be tritium water.

[0018] And, it may further include a heat exchanger that raises the temperature of the radioactive wastewater.

[0019] At this time, the heat exchanger may be a coil-type heat exchanger that raises the temperature of the radioactive wastewater by utilizing geothermal heat from the seabed.

[0020] In addition, the reactor may further contain an anti-agglomerant (AA).

[0021] Meanwhile, according to another embodiment of the present invention, a radioactive wastewater-based gas hydrate storage system is provided, comprising: a radioactive wastewater-based gas hydrate generating device according to the present invention as described above; and a discharge pipe for discharging the generated gas hydrate into the marine subsurface.

[0022] Meanwhile, according to another embodiment of the present invention, a method for storing gas hydrate based on radioactive wastewater is provided, comprising: (S10) a step of arranging one end of a cylindrical reactor having a specific length and diameter in the direction of the ocean surface and the other end in the direction of the ocean deep to induce a temperature difference inside the reactor; (S20) a step of injecting gaseous gas and radioactive wastewater into the reactor, wherein the radioactive wastewater is placed in the lower part of the reactor and the gaseous gas is placed in the upper part of the radioactive wastewater; (S30) a step of applying pressure inside the reactor to convert the gaseous gas into liquefied gas; and (S40) a step of applying heat to the radioactive wastewater so that the liquefied gas boils and gas hydrate is generated.

[0023] At this time, the step (S40) is performed after the above step and may further include the step (S50) of discharging the generated gas hydrate into the ocean ground. Effects of the invention

[0024] According to one embodiment of the present invention, by generating gas hydrate using radioactive wastewater, tritium, a radioactive material, can be stably solidified.

[0025] In addition, radioactive materials can be safely isolated from nature by storing stably solidified radioactive wastewater-based gas hydrates in the ocean ground.

[0026] In addition, it is possible to contribute to preventing global warming by forming and sequestering gas hydrates using greenhouse gases such as carbon dioxide.

[0027] Meanwhile, the effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention. Brief explanation of the drawing

[0028] FIG. 1 is a schematic diagram showing a radioactive wastewater-based gas hydrate generating device according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing a radioactive wastewater-based gas hydrate generating device according to another embodiment of the present invention. FIGS. 3 to 5 are drawings illustrating the operation of a radioactive wastewater-based gas hydrate generating device according to one embodiment of the present invention. FIG. 6 is a schematic diagram showing a radioactive wastewater-based gas hydrate storage system according to one embodiment of the present invention. Specific details for implementing the invention

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention.

[0030] The embodiments of the present invention described below are provided to more clearly explain the present invention to those skilled in the art, and the scope of the present invention is not limited by the following embodiments, and the following embodiments may be modified in various other forms.

[0031] The terms used herein are for describing specific embodiments and are not intended to limit the invention. Terms used herein in the singular form may include plural forms unless the context clearly indicates otherwise. Additionally, the terms “comprise” and / or “comprising” used herein specify the presence of the mentioned features, steps, numbers, actions, components, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, steps, numbers, actions, components, elements, and / or groups thereof. Furthermore, the term “connected” used herein means not only that components are directly connected, but also includes the concept of indirectly connecting components through the interposition of additional components between them.

[0032] Furthermore, when a component is described in this specification as being located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components. The term "and / or" as used in this specification includes any one of the listed items and all combinations of one or more thereof. Additionally, terms of degree such as "about" and "substantially" as used in this specification are used to mean a range of numerical values ​​or degrees or approximate values, taking into account inherent manufacturing and material tolerances, and are used to prevent an infringer from unfairly exploiting the disclosures in which precise or absolute figures provided to aid in understanding this specification are mentioned.

[0034] FIG. 1 is a schematic diagram showing a radioactive wastewater-based gas hydrate generating device according to one embodiment of the present invention. FIG. 2 is a schematic diagram showing a radioactive wastewater-based gas hydrate generating device according to another embodiment of the present invention.

[0035] Also, FIGS. 3 to 5 are drawings illustrating the operation of a radioactive wastewater-based gas hydrate generating device according to one embodiment of the present invention.

[0036] Referring to FIGS. 1 to 5, a radioactive wastewater-based gas hydrate generating device (10) according to one aspect of the present invention comprises a reactor (1) that is disposed on the seabed and generates gas hydrate, wherein radioactive wastewater is disposed on the lower side inside the reactor (1), liquefied gas is disposed on the upper side of the radioactive wastewater, and gas hydrate is generated at the interface between the radioactive wastewater and the liquefied gas.

[0037] The reactor (1) liquefies gaseous gas supplied from the outside to produce liquefied gas and stores the produced liquefied gas.

[0038] The above reactor (1) may be formed in a cylindrical shape having a specific length and diameter, and provides a space inside where gaseous gas is converted into a liquid state.

[0039] At this time, the diameter of the reactor (1) can be set to a predetermined value according to the user's needs. Also, one end of the reactor (1) can be positioned toward the ocean surface, and the other end can be positioned toward the ocean depth. Accordingly, the length of the reactor (1) can be a length corresponding to the depth of the sea, and can be 100 m or more.

[0040] Also, the other end of the reactor (1) may be formed in a tapered shape, and in this case, when connected to the discharge pipe (20) described later, gas hydrate discharge may be made more easily.

[0041] Here, the liquefied gas may include liquefied greenhouse gas, and the gas hydrate may include greenhouse gas hydrate; more specifically, the liquefied gas may include carbon dioxide and / or a mixed gas containing carbon dioxide. In this case, the carbon dioxide may be carbon dioxide emitted from a factory that uses a large amount of fuel, such as a steel mill. Accordingly, the reactor (1) is connected to a carbon dioxide source (not shown), such as a factory that uses a large amount of fuel, such as a steel mill, by a supply pipe connecting the reactor (1), and a supply pump may be placed on the supply pipe to facilitate the flow of carbon dioxide.

[0042] In addition, the above radioactive wastewater may be tritium water containing tritium.

[0043] In this way, by forming gas hydrates using radioactive wastewater and greenhouse gases such as carbon dioxide, it is possible to simultaneously achieve the sequestration of radioactive materials and greenhouse gases.

[0044] In particular, gas hydrates formed from water containing deuterium or tritium have superior thermodynamic stability because the temperature at which they are formed is higher than when formed from ordinary water. Therefore, when forming gas hydrates using radioactive wastewater, T2O molecules containing tritium have a large driving force, so there is an advantage in that they can be stably solidified and stored.

[0045] In addition, the radioactive wastewater-based gas hydrate generating device (10) according to the present invention may further include a heat exchanger (2) that raises the temperature of the radioactive wastewater.

[0046] At this time, the heat exchanger (2) may be a coil-type heat exchanger that raises the temperature of the radioactive wastewater using geothermal heat from the seabed. In this case, only geothermal heat from the seabed can be transferred to the radioactive wastewater inside the reactor without the inflow of additional materials such as surface seawater.

[0047] In addition, an anti-agglomerant (AA) may be further included in the reactor (1), and due to the anti-agglomerant, the formed gas hydrate may have the form of a slurry. This ensures the fluidity of the gas hydrate. As a result, the gas hydrate can be smoothly discharged into the marine subsurface through the discharge pipe (20) described later.

[0048] Here, the anti-coagulation agent may be a surfactant such as span80, tween80, or rhamnolipid, or a quaternary ammonium salt surfactant such as n-dodecyl-tri(n-butyl)-ammonium chloride, but is not limited thereto.

[0049] Meanwhile, a method for storing gas hydrate based on radioactive wastewater according to another aspect of the present invention comprises: (S10) a step of inducing a temperature difference inside the reactor by positioning one end of a cylindrical reactor having a specific length and diameter toward the ocean surface and the other end toward the ocean depth; (S20) a step of injecting gaseous gas and radioactive wastewater into the reactor, wherein the radioactive wastewater is positioned at the lower end of the reactor and the gaseous gas is positioned at the upper end of the radioactive wastewater; (S30) a step of converting the gaseous gas into liquefied gas by applying pressure inside the reactor; and (S40) a step of applying heat to the radioactive wastewater so that the liquefied gas boils and gas hydrate is generated.

[0050] First, regarding step (S10), the reactor (1) is the same as the one used in the aforementioned radioactive wastewater-based gas hydrate generating device, so a detailed description thereof is omitted.

[0051] As water temperature gradually decreases from the ocean surface to the ocean depths, and pressure gradually increases. Therefore, by positioning one end of the reactor (1) toward the ocean surface and the other end toward the ocean depths, the lower side of the reactor (1) becomes relatively colder and the upper side becomes relatively hotter, so a temperature difference inside the reactor (1) can be naturally induced.

[0052] Here, the gas may include a greenhouse gas, and the gas hydrate may include a greenhouse gas hydrate; more specifically, the gas may include carbon dioxide and / or a mixed gas containing carbon dioxide.

[0053] Next, in relation to step (S20), when gaseous gas and radioactive wastewater are injected into the reactor (1), the radioactive wastewater with a relatively high density is placed at the lower side inside the reactor (1), and gaseous gas with a relatively low density is placed at the upper side of the radioactive wastewater.

[0054] At this time, an anti-agglomerant (AA) may be additionally injected into the reactor (1). Due to the anti-agglomerant, the gas hydrate subsequently formed may take the form of a slurry. This ensures the fluidity of the gas hydrate. As a result, the gas hydrate can be smoothly discharged into the marine subsurface through the discharge pipe (20) described later. The specific type of the anti-agglomerant is as described above.

[0055] Next, in relation to step (S30), pressure is applied within the reactor (1) to convert the gaseous gas into liquefied gas.

[0056] At this time, as the pressure gradually increases from the ocean surface to the ocean depth, the water pressure of the ocean depth is applied to the gaseous gas stored in the reactor (1), thereby liquefying the gaseous gas supplied into the reactor (1) and generating liquefied gas.

[0057] Next, in relation to step (S40), heat is applied to the radioactive wastewater so that the liquefied gas boils and gas hydrate is produced.

[0058] Here, the heat applied to the radioactive wastewater may be geothermal heat from the seabed, and such geothermal heat may be transferred to the radioactive wastewater through a coil-type heat exchanger.

[0059] In this way, geothermal heat transferred to the radioactive wastewater raises the temperature of the radioactive wastewater. As a result, vaporization occurs at the bottom of the liquefied gas due to the high temperature of the radioactive wastewater, causing boiling. The liquefied gas and the radioactive wastewater are agitated by the boiling liquefied gas, and gas hydrate is rapidly formed.

[0060] Here, since the liquefied gas and radioactive wastewater are agitated as the gas-liquid contact area increases due to boiling, a separate agitation device may not be required. Accordingly, the cost and energy required for the installation and operation of the agitation device can be reduced.

[0061] Meanwhile, during the process of boiling the liquefied gas, some of the liquefied gas is converted into a gaseous state and moves to the upper part of the reactor (1), but is liquefied again by the pressure inside the reactor (1) and then descends to the lower part of the reactor (1), and can then be used again to produce gas hydrate.

[0062] And, according to another embodiment of the present invention, the step (S40) is performed after the above step (S50), and may further include the step of discharging the generated gas hydrate into the ocean ground.

[0064] FIG. 6 is a schematic diagram showing a radioactive wastewater-based gas hydrate storage system according to one embodiment of the present invention.

[0065] Referring to FIG. 6, a radioactive wastewater-based gas hydrate storage system (100) according to another aspect of the present invention comprises a radioactive wastewater-based gas hydrate generating device (10) according to one aspect of the present invention described above; and a discharge pipe (20) for discharging the generated gas hydrate into the ocean ground.

[0066] When a certain amount of gas hydrate is produced inside the reactor (1) by the radioactive wastewater-based gas hydrate generating device (10), the produced gas hydrate can be stored in the ocean ground.

[0067] Here, the marine subsurface where gas hydrate is stored may be a seafloor cavity formed by the mining of minerals such as oil or a naturally formed seafloor cavity.

[0068] A discharge pipe (20) is used for storing gas hydrate. One end of the discharge pipe (20) is connected to the lower part of the reactor (1), and the other end can be connected to the marine underground where the gas hydrate is stored.

[0069] According to the present invention, by generating gas hydrate using radioactive wastewater, tritium, a radioactive material, can be stably solidified, and by storing the stably solidified radioactive wastewater-based gas hydrate in the ocean ground, radioactive materials can be safely isolated from nature.

[0070] And, a reactor (1) in which a gas hydrate generation reaction takes place is placed on the seabed, and gaseous gas is liquefied through water pressure and the liquefied gas is produced into gas hydrate, thereby reducing the energy required in the gas hydrate generation process.

[0071] In addition, the present invention stores the gas hydrate generated in the reactor (1) placed on the seabed in the ocean ground, so the path for transporting the gas hydrate to the ocean ground is shortened, and accordingly, leakage of gas that may occur during the transport of greenhouse gases such as carbon dioxide can be prevented.

[0072] Furthermore, the present invention forms gas hydrate by boiling liquefied gas using seabed geothermal heat applied to radioactive wastewater, so gas hydrate can be formed quickly without using a separate stirring device.

[0074] This specification discloses preferred embodiments of the present invention. Although specific terms have been used, they are used merely in a general sense to facilitate the explanation of the technical content of the invention and to aid in understanding the invention, and are not intended to limit the scope of the invention. It is obvious to those skilled in the art that, in addition to the embodiments disclosed herein, other variations based on the technical concept of the present invention are possible. For example, those skilled in the art will understand that the radioactive wastewater-based gas hydrate generating device, storage system, and storage method according to the embodiments can be varied in many ways. Therefore, the scope of the invention should not be determined by the described embodiments but by the technical concept described in the claims. Explanation of the symbols

[0075] 1: Reactor 2: Heat exchanger 10: Radioactive Wastewater-Based Gas Hydrate Generator 20: Discharge pipe 100: Radioactive Wastewater-Based Gas Hydrate Storage System

Claims

Claim 1 A radioactive wastewater-based gas hydrate generating device comprising a reactor disposed on the seabed and generating gas hydrate, wherein radioactive wastewater containing deuterium or tritium is disposed in the lower part inside the reactor, liquefied gas is disposed in the upper part of the radioactive wastewater, and gas hydrate is generated at the interface between the radioactive wastewater and the liquefied gas. Claim 2 A radioactive wastewater-based gas hydrate generating device according to claim 1, wherein the reactor is cylindrical having a specific length and diameter, with one end positioned toward the ocean surface and the other end positioned toward the ocean depth. Claim 3 A radioactive wastewater-based gas hydrate generating device according to claim 1, wherein the liquefied gas comprises liquefied carbon dioxide and the gas hydrate comprises carbon dioxide hydrate. Claim 4 A radioactive wastewater-based gas hydrate generating device according to claim 1, wherein the radioactive wastewater contains tritium water. Claim 5 A radioactive wastewater-based gas hydrate generating device according to claim 1, further comprising a heat exchanger that raises the temperature of the radioactive wastewater. Claim 6 A radioactive wastewater-based gas hydrate generating device according to claim 5, wherein the heat exchanger is a coil-type heat exchanger that raises the temperature of the radioactive wastewater using geothermal heat from the seabed. Claim 7 A radioactive wastewater-based gas hydrate generating device according to claim 1, wherein the reactor further comprises an anti-agglomerant (AA). Claim 8 A radioactive wastewater-based gas hydrate generating device according to any one of claims 1 to 7; and a radioactive wastewater-based gas hydrate storage system comprising a discharge pipe for discharging the generated gas hydrate into the marine subsurface. Claim 9 (S10) a step of positioning one end of a cylindrical reactor having a specific length and diameter toward the ocean surface and the other end toward the ocean depth to induce a temperature difference inside the reactor; (S20) a step of injecting radioactive wastewater containing gaseous gas and deuterium or tritium into the reactor, wherein the radioactive wastewater is positioned at the lower end of the reactor and the gaseous gas is positioned at the upper end of the radioactive wastewater; (S30) a step of applying pressure inside the reactor to convert the gaseous gas into liquefied gas; and (S40) a step of applying heat to the radioactive wastewater to cause the liquefied gas to boil and generate gas hydrate, comprising a method for storing gas hydrate based on radioactive wastewater. Claim 10 A radioactive wastewater-based gas hydrate storage method according to claim 9, wherein the gas comprises carbon dioxide and the gas hydrate comprises carbon dioxide hydrate. Claim 11 A method for storing gas hydrates based on radioactive wastewater according to claim 9, wherein the heat applied to the radioactive wastewater is seafloor geothermal heat. Claim 12 A radioactive wastewater-based gas hydrate storage method according to claim 11, wherein the geothermal heat from the seabed is transferred to the radioactive wastewater through a coiled heat exchanger. Claim 13 A radioactive wastewater-based gas hydrate storage method according to claim 9, wherein step (S20) further injects an anti-agglomerant (AA) into the reactor. Claim 14 A radioactive wastewater-based gas hydrate storage method according to claim 9, further comprising the step (S50) of discharging the generated gas hydrate into the ocean ground, which is performed after the step (S40).

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