Carbon dioxide removal device and carbon dioxide removal method

Abstract

The present invention provides a carbon dioxide removal device and a carbon dioxide removal method that can remove carbon dioxide without requiring a water supply. [Solution] The carbon dioxide removal device 100 is characterized by comprising a plasma treatment passage 10 for generating plasma in the gas to be treated flowing through the flow path, and an adsorption treatment passage 20 for introducing the gas to be treated with generated plasma and passing it through the steel slag layer 24. Furthermore, the carbon dioxide removal method is characterized by performing plasma treatment, in which plasma is generated in the gas to be treated while the gas containing carbon dioxide is flowing, and adsorption treatment, in which the gas to be treated with generated plasma by the plasma treatment is passed through the steel slag layer 24. With this configuration, it is possible to remove carbon dioxide without requiring the supply of moisture.

Description

Technical Field

[0001] The present invention relates to a carbon dioxide removal apparatus and a carbon dioxide removal method for removing carbon dioxide contained in a gas to be treated.

Background Art

[0002] As a measure against global warming, efforts have been made to reduce carbon dioxide emissions in various industries. As a carbon dioxide removal technology for this purpose, there has been one disclosed in Non-Patent Document 1. The carbon dioxide removal technology disclosed in the same document is to form steel slag powder mainly composed of calcium oxide into a porous body, pour moisture onto this formed body, and advance the reaction between carbon dioxide and calcium oxide, thereby precipitating calcium carbonate between slag particles of the formed body.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, with the conventional carbon dioxide removal technologies described above, it is necessary to continuously add sufficient moisture to the porous molded body of steel slag powder that comes into contact with the gas to be treated in order to promote the reaction between calcium oxide and carbon dioxide. In cases where such moisture supply is not permitted, for example, in sites where a moisture supply system cannot be installed, or in sites where high humidity of the gas to be treated is undesirable, these technologies cannot be applied. Furthermore, when using steel slag powder, the content of silicon dioxide and other elements in the steel slag powder is high, and the calcium oxide content is only about 40%, which poses a problem as this low calcium oxide content is disadvantageous for carbon dioxide removal.

[0005] Therefore, the present invention has been made in view of these problems, and its objective is to provide a novel and improved carbon dioxide removal device and carbon dioxide removal method that can remove carbon dioxide without requiring a water supply. [Means for solving the problem]

[0006] To solve the above problems, according to a first aspect of the present invention, a carbon dioxide removal device is provided, characterized by comprising a plasma treatment path for generating plasma in a gas to be treated flowing through a channel, and an adsorption treatment path for introducing the gas to be treated, which has generated plasma, and passing it through a steel slag layer.

[0007] In this configuration, when a gas containing carbon dioxide is introduced into the plasma processing path, plasma is generated in the gas, causing carbon dioxide to be ionized or excited. The gas containing the cations generated by the ionization of carbon dioxide and the excited carbon dioxide is then passed through the steel slag layer in the adsorption processing path. As a result, carbon dioxide can be removed without the need for water supply.

[0008] Various applications of the present invention are conceivable. For example, the system may comprise a plurality of plasma processing paths and a plurality of adsorption processing paths, with the plasma processing paths and adsorption processing paths alternately arranged from upstream to downstream. With such a configuration, carbon dioxide can be removed multiple times between the time the gas to be processed is sent to the upstream plasma processing path and discharged from the downstream adsorption processing path. This allows for gradual removal of carbon dioxide from the gas to be processed, resulting in a particularly high final carbon dioxide removal rate.

[0009] Furthermore, the flow path of the plasma processing path is formed between a cylindrical electrode and an axial electrode coaxially arranged inside the cylindrical electrode, and plasma is generated in the gas to be processed by applying a voltage between the cylindrical electrode and the axial electrode, and the adsorption processing path may be connected to the downstream side of the flow path of the plasma processing path. With this configuration, plasma is generated in the gas to be processed by applying a voltage throughout the entire flow path between the cylindrical electrode and the axial electrode, and it can be immediately sent to the adsorption processing path, making it easy to ionize and excite the carbon dioxide contained in the gas to be processed before it reaches the quicklime layer.

[0010] Furthermore, the steel slag layer may be constructed by stacking multiple layers of steel slag. With such a configuration, the steel slag layer can be easily constructed.

[0011] Furthermore, according to a second aspect of the present invention, a method for removing carbon dioxide is provided, characterized by performing a plasma treatment in which plasma is generated in a gas to be treated while the gas containing carbon dioxide is flowing through the gas, and an adsorption treatment in which the gas to be treated, from which plasma has been generated by the plasma treatment, is passed through a steel slag layer.

[0012] With this configuration, when plasma is generated in a gas to be treated that contains carbon dioxide, the carbon dioxide can be ionized or excited. When the gas to be treated, which contains the cations generated by the ionization of carbon dioxide and the excited carbon dioxide, is passed through a steel slag layer, the aforementioned cations and excited carbon dioxide can be adsorbed onto the steel slag. Therefore, carbon dioxide can be removed without the need for water supply.

[0013] Furthermore, the plasma treatment and the adsorption treatment may be repeated alternately multiple times from the upstream side to the downstream side. With this configuration, the removal of carbon dioxide from the gas to be treated is gradually advanced, and the final carbon dioxide removal rate can be made particularly high.

[0014] Furthermore, the plasma treatment is a process in which the gas to be treated is flowed through a channel between a cylindrical electrode and an axial electrode coaxially arranged inside the cylindrical electrode, and a voltage is applied between the cylindrical electrode and the axial electrode, and the adsorption treatment may be a process in which the gas to be treated, which has generated plasma, is passed through the steel slag layer in a pipeline connected to the downstream side of the channel. With such a configuration, it becomes easy to reach the steel slag layer in an ionized and excited state with the carbon dioxide contained in the gas to be treated.

[0015] Furthermore, the steel slag layer may be constructed by stacking multiple layers of steel slag. With such a configuration, the steel slag layer can be easily constructed. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a novel and improved carbon dioxide removal device and carbon dioxide removal method that can remove carbon dioxide without requiring a water supply. Other effects of the present invention will be explained in the embodiments for carrying out the invention described later. [Brief explanation of the drawing]

[0017] [Figure 1]It is a longitudinal front view showing a carbon dioxide removal device 100 according to the first embodiment. [Figure 2] It is a front view showing a carbon dioxide removal device 200 according to the second embodiment.

Mode for Carrying Out the Invention

[0018] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and duplicate description is omitted.

[0019] (First Embodiment) The carbon dioxide removal device 100 according to the first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a longitudinal front view showing the carbon dioxide removal device 100 according to the first embodiment. As shown in FIG. 1, the carbon dioxide removal device 100 is composed of a single plasma treatment path 10 and a single adsorption treatment path 20 continuous on the downstream side of the plasma treatment path 10. Hereinafter, each component will be described in detail.

[0020] As shown in FIG. 1, the plasma treatment path 10 includes a cylindrical electrode 11, an axial electrode 12 arranged coaxially with the cylindrical electrode 11 inside the cylindrical electrode 11, a plurality of insulating spacers 13 for holding the axial electrode 12 coaxially with the cylindrical electrode 11, and an introduction path 15 for introducing the gas to be treated into the flow path 14 formed by the cylindrical electrode 11 and the axial electrode 12.

[0021] The plasma treatment path 10 allows the gas to be treated to flow from the introduction path 15 into the flow path 14, and gives electrical energy to the gas to be treated flowing through the flow path 14 by an electric field generated between the cylindrical electrode 11 and the axial electrode 12. Thereby, it becomes an atmospheric pressure plasma generator that stably generates plasma in the gas to be treated under atmospheric pressure and allows the gas to be treated in which plasma has been generated to flow out from the flow path 14.

[0022] The cylindrical electrode 11 of the plasma processing path 10 has a long straight tubular shape and serves as a cathode with an inner circumference formed in a cylindrical surface shape. Hereinafter, the direction along the tube axis of the cylindrical electrode 11 is referred to as the axial direction, the direction perpendicular to the tube axis is referred to as the radial direction, and the circumferential direction around the tube axis is referred to as the circumferential direction.

[0023] The axial electrode 12 of the plasma processing path 10 serves as an anode with the outer circumference of a straight shaft body extending in the axial direction formed in a cylindrical surface shape. The axial electrode 12 faces the cylindrical electrode 11 in the radial direction.

[0024] As the cylindrical electrode 11 and the axial electrode 12, it is preferable to use a seamless pipe without joints, and the material thereof is not particularly limited. For example, it may be a stainless steel pipe, or a conductive resin (CFRP: Carbon Fiber Reinforced Plastics) pipe reinforced with carbon such as graphite or carbon nanotubes. Alternatively, it may be a pipe with a resin layer containing carbon such as graphite or carbon nanotubes coated on the inner peripheral surface or the outer peripheral surface of a stainless steel pipe. Note that a seamless stainless steel pipe is expensive, heavy, difficult to withstand high temperatures of 400 °C or higher, and may be corroded by strong acids and strong alkalis, so a conductive resin pipe is more preferable.

[0025] The insulating spacer 13 is formed of, for example, a fluorine-based resin and has excellent chemical resistance and heat resistance. The insulating spacer 13 is preferably, for example, substantially X-shaped or substantially Y-shaped when viewed from the axial direction in order to coaxialize the core. In addition, the insulating spacer 13 is preferably composed of a frame as thin as possible so as not to obstruct the flow of the processing gas.

[0026] The flow path 14 of the plasma processing path 10 is formed between the inner circumference of the cylindrical electrode 11 and the outer circumference of the axial electrode 12 and extends in the axial direction with an annular flow path cross section.

[0027] When a voltage of 13,000 to 25,000 V is applied between the cylindrical electrode 11 and the axial electrode 12 by an electrical circuit connected to the axial electrode 12, a discharge occurs between the cylindrical electrode 11 and the axial electrode 12. Electrical energy is supplied to the gas being processed as it flows through the electric field of this discharge, causing plasma to be generated in the gas being processed. When plasma is generated in a gas being processed that contains carbon dioxide, the carbon dioxide is ionized or excited. Adding gases to the gas being processed to facilitate plasma generation is unnecessary and, considering operating costs, is preferable not to do so. For example, adding noble gases such as argon (Ar) gas or helium (He) gas to the gas being processed and sending it into the flow path 14 will facilitate plasma generation, but this would involve using expensive gases, which is undesirable.

[0028] The discharge between the cylindrical surfaces of the cylindrical electrode 11 and the axial electrode 12 generates plasma throughout the entire flow channel 14. Therefore, it is possible to continuously process the gas to be processed by supplying it to the flow channel 14, converting it into plasma up to the downstream end of the flow channel 14, and then quickly sending it from the flow channel 14 to the adsorption processing channel 20.

[0029] Here, if there are irregularities on the cylindrical electrode 11 and the axial electrode 12, spark discharge will occur at those locations. When spark discharge, such as corona discharge or glow discharge, occurs, plasma is generated only in the vicinity of the spark discharge, making it difficult to achieve the effects of plasma treatment. Also, if the voltage applied between the cylindrical electrode 11 and the axial electrode 12 is too high, or if the distance between the cylindrical electrode 11 and the axial electrode 12 is too short, spark discharge may occur. A voltage of 23,000V is the upper limit to prevent spark discharge when the distance between the cylindrical electrode 11 and the axial electrode 12 is 40mm. The voltage applied between the cylindrical electrode 11 and the axial electrode 12 should be adjusted appropriately according to the dimensions of the cylindrical electrode 11 and the axial electrode 12 so that spark discharge does not occur. Note that if the applied voltage is 30,000V or less, the amount of nitrogen oxide (NOx) generated can be suppressed to a negligible level. The positions of the cylindrical electrode 11 and the axial electrode 12 and the electrical circuit are not particularly limited, but in the example shown in Figure 1, they are located near the axial center of the cylindrical electrode 11 and the axial electrode 12.

[0030] To process a large amount of gas in the plasma processing path 10, for example, the inner diameter of the cylindrical electrode 11 is 100 mm, the outer diameter of the axial electrode 12 is 20 mm, and the axial length of the region where the cylindrical electrode 11 and the axial electrode 12 face each other radially is 1600 mm. These dimensions are just an example and are not limited to them. The outer diameter of the axial electrode 12 should be 10 mm or more. On the other hand, if the inner diameter of the cylindrical electrode 11 is made too large, the distance between the cylindrical electrode 11 and the axial electrode 12 becomes long, making it difficult for discharge to occur. For this reason, it is preferable to satisfy 3 ≤ (inner diameter of cylindrical electrode 11 / outer diameter of axial electrode 12) ≤ 6, (inner diameter of cylindrical electrode 11 - outer diameter of axial electrode 12) ≥ 20 mm, and the outer diameter of the axial electrode 12 ≥ 10 mm.

[0031] Furthermore, if the cylindrical electrode 11 and the axial electrode 12 are made too long in the axial direction, it becomes difficult to hold the cylindrical electrode 11 and the axial electrode 12 concentrically in the flow path 14 with the insulating spacer 13. For this reason, it is preferable that the axial length of the flow path 14 be between 500 mm and 2000 mm.

[0032] The introduction passage 15 of the plasma processing passage 10 has a guide vane section that changes the flow of the gas to be processed toward the flow path 14 into a helical flow, and two or more obstruction sections that generate wake vortices in the aforementioned helical flow in the intermediate flow path between the guide vane section and the flow path 14. A plasma processing passage having such an introduction passage is disclosed in detail in Japanese Patent Application Publication No. 2021-126633.

[0033] The gas to be treated, introduced into the introduction channel 15, changes into a spiral flow (helical flow) that swirls in one direction downstream in the axial direction as it passes through the guide vane section, and further changes into a spiral flow including wake vortices upon hitting an obstacle. Subsequently, the gas to be treated flows into the upstream inlet of the channel 14 and passes through the channel 14 in a spiral flow state that swirls in one direction downstream in the axial direction. Due to this spiral flow and the generation of wake vortices, the gas to be treated flows along a long path in the channel 14, and the probability of the molecules of the gas to be treated being affected by the plasma is higher compared to when it flows straight in the axial direction.

[0034] While it is not essential to employ helical flow or wake vortex formation for the gas being treated, it is preferable to do so in order to increase the probability of ionization and excitation of carbon dioxide (CO2 molecules) contained in the gas being treated. The axial length of the flow path 14 is preferably 1000 mm or more in order to increase the travel distance of the helical flow of the gas being treated.

[0035] The adsorption processing path 20 is a pipeline formed by a connecting path 21 connected to the downstream side of the flow path 14 of the plasma processing path 10, an adsorption pipeline 22 connected to the downstream side of the connecting path 21, and an exhaust path 23 connected to the downstream side of the adsorption pipeline 22.

[0036] The connecting passage 21 introduces the gas to be treated, which has flowed out from the downstream side of the flow path 14 of the plasma processing passage 10, to the upstream side of the adsorption pipeline 22. The adsorption pipeline 22 has a steel slag layer 24 arranged inside a straight tube and permeable barriers 22a arranged on the upstream and downstream sides of the steel slag layer 24, respectively. The exhaust passage 23 causes the gas to be treated, which has flowed out from the downstream side of the adsorption pipeline 22, to flow out of the adsorption processing passage 20.

[0037] The steel slag layer 24 is formed by randomly packing numerous steel slags 24a inside the adsorption pipeline 22, and randomly forming gaps 24b between the layered steel slags 24a to allow the gas to be treated to pass through. The steel slag layer 24 is maintained in this state by an upstream permeable barrier 22a and a downstream permeable barrier 22a. The permeable barrier 22a is a member that restricts the movement of the steel slags 24a while allowing the gas to be treated to pass through, and is, for example, a mesh member that does not allow the steel slags 24a to pass through.

[0038] As steel slag 24a, general steel slag is used. Steel slag is a by-product generated in the steel manufacturing process and includes blast furnace slag and steelmaking slag. Steel slag is mainly composed of lime and silica. Other components include alumina, magnesium oxide, and small amounts of sulfur in blast furnace slag, and iron oxide and magnesium oxide in steelmaking slag. In the case of steelmaking slag, metal elements are incorporated into the slag in the form of oxides, but because the refining time is short and the lime content is high, some of the lime used as a secondary raw material remains undissolved as free lime. These components exist in nature, such as in the earth's crust, natural rocks, and minerals, and their chemical composition is similar to that of Borland cement. The shape and physical properties of steel slag are similar to those of general rubble or sand, but differences in chemical composition and cooling processes can give it a wide range of properties unique to slag.

[0039] For forming the adsorption treatment channel 20, it is preferable to use a resin pipe such as a polyvinyl chloride pipe, as it has poor reactivity with the gas to be treated and excellent insulating properties. In the example shown in Figure 1, the plasma treatment channel 10 and the adsorption treatment channel 20 are arranged in parallel to make the overall axial length of the carbon dioxide removal device 100 compact, and a curved connecting channel 21 is used as a relay. However, the shape of the connecting channel can be changed as appropriate, such as to a straight pipe. In order to allow the plasma-treated gas to reach the adsorption treatment channel as quickly as possible, it is preferable to shorten the path length from the flow path of the plasma treatment channel 10 to the steel slag layer 24 as much as possible. In addition, although the adsorption treatment channel 20 is connected to the plasma treatment channel 10 by a connecting channel 21 that is separate from the adsorption pipeline 22, the pipeline for the adsorption treatment channel may be formed with a single, seamless pipe.

[0040] A blower (not shown) that sends the gas to be treated into the introduction passage 15 of the plasma treatment passage 10 and discharges it out through the exhaust passage 23 of the adsorption treatment passage 20 may be positioned either upstream or downstream of the carbon dioxide removal device 100. The carbon dioxide removal device 100 cannot be anticipated in terms of the situations in which it will be used, and it may be used in sites where the gas to be treated contains harmful substances such as strongly acidic or strongly alkaline substances. Considering the adverse effects of these harmful substances on the surface of the blower blades, etc., it is preferable to position the blower downstream of the carbon dioxide removal device 100, as decomposition of harmful substances can be expected as the gas to be treated is plasma-treated in the plasma treatment passage 10.

[0041] The flow velocity of the gas to be treated in channel 14 affects the performance of plasma generation of the gas to be treated, and the flow velocity of the gas to be treated in the steel slag layer 24 affects the adsorption performance by the steel slag 24a. Therefore, the flow velocity of the gas to be treated in channel 14 should be set considering the required degree of ionization and the required carbon dioxide removal rate of the gas to be treated, and controlled by the output of the blower.

[0042] Furthermore, when a gas to be treated containing water vapor is fed into the plasma processing path 10, the higher the humidity of the gas to be treated, the more likely spark discharge is to occur between the cylindrical electrode 11 and the axial electrode 12 in the flow path 14. Frequent spark discharge in the flow path 14 is undesirable because it easily generates nitrogen oxides due to the excitation of nitrogen and oxygen contained in the gas to be treated. For this reason, the lower the humidity of the gas to be treated fed into the plasma processing path 10, the better, and there is no problem if a dry gas to be treated is fed in. However, if the humidity of the gas to be treated is a problem, it is advisable to place a steam-water separator (not shown) upstream of the carbon dioxide removal device 100 to maintain the humidity of the gas to be treated fed into the plasma processing path 10 below a predetermined level, for example, below 50%. Even with such a dry gas to be treated, if the gas to be treated is plasma-treated, it is possible to remove carbon dioxide through the adsorption effect of the steel slag 24a.

[0043] The carbon dioxide removal device 100 is as described above and includes a plasma treatment path 10 for generating plasma in the gas to be treated flowing through the flow path 14, and an adsorption treatment path 20 for introducing the gas to be treated with generated plasma and passing it through the steel slag layer 24.

[0044] When the gas to be treated, which contains carbon dioxide, is introduced into the plasma processing channel 10, plasma is generated in the gas flowing through the channel 14. During this process, carbon dioxide is ionized or excited. The gas to be treated, which contains the cations generated by the ionization of carbon dioxide and the excited carbon dioxide, flows from the channel 14 to the adsorption processing channel 20 and passes through the steel slag layer 24. During this passage, the cations generated by the ionization of carbon dioxide and the excited carbon dioxide are adsorbed onto the steel slag 24a. Thus, carbon dioxide can be removed.

[0045] Furthermore, in the carbon dioxide removal device 100, the flow path 14 of the plasma processing path 10 is formed between a cylindrical electrode 11 and an axial electrode 12 coaxially arranged inside the cylindrical electrode 11. Plasma is generated in the gas to be treated by applying a voltage between the cylindrical electrode 11 and the axial electrode 12. In addition, the adsorption processing path 20 is connected to the downstream side of the flow path 14 of the plasma processing path 10. Therefore, plasma is generated in the gas to be treated by applying a voltage throughout the entire flow path 14 between the cylindrical electrode 11 and the axial electrode 12, and it can be immediately sent to the adsorption processing path 20. As a result, the carbon dioxide removal device 100 makes it easy to deliver the carbon dioxide contained in the gas to be treated in an ionized and excited state to the steel slag layer 24.

[0046] Furthermore, the carbon dioxide removal method according to this embodiment includes a plasma treatment in which plasma is generated in the gas to be treated while the gas containing carbon dioxide is flowing, and an adsorption treatment in which the gas to be treated, from which the plasma has been generated by the plasma treatment, is passed through a steel slag layer 24. Therefore, when plasma is generated in the gas to be treated containing carbon dioxide, the carbon dioxide can be ionized or excited. When the gas to be treated, which contains cations generated by the ionization of carbon dioxide or excited carbon dioxide, is passed through the steel slag layer 24, the aforementioned cations and excited carbon dioxide can be adsorbed.

[0047] Furthermore, the plasma treatment of the carbon dioxide removal method according to this embodiment involves flowing the gas to be treated through a flow path 14 between a cylindrical electrode 11 and an axial electrode 12 coaxially arranged inside the cylindrical electrode 11, and applying a voltage between the cylindrical electrode 11 and the axial electrode 12. The adsorption treatment involves passing the gas to be treated, which has generated the plasma, through a steel slag layer 24 in a pipeline (adsorption treatment channel 20) connected to the downstream side of the flow path 14. This makes it easy to deliver the carbon dioxide contained in the gas to be treated to the steel slag layer 24 in an ionized and excited state.

[0048] (Examples) Using a test unit of the carbon dioxide removal device 100 according to this embodiment, as shown in Figure 1, we conducted tests to evaluate the carbon dioxide removal performance.

[0049] The main specifications of the test machine are as follows: • Electrical circuit specifications: 3A, 12V (power consumption: 36W), converter input 100V: output 12kV • Fan specifications: 30 m³ / hour • Cylindrical electrode 11: Made of carbon pipe with a diameter of 45 mm and a length of 500 mm. • Axial electrode 12: Made of carbon pipe with a diameter of 10 mm and a length of 500 mm. • Adsorption pipeline 22: Made of PVC pipe with a diameter of 45mm and a length of 500mm.

[0050] An aluminum flexible duct is connected to the introduction passage 15, and a blower (fan) is attached to the aluminum flexible duct. Air from the test room where the test machine is installed is drawn into the aluminum flexible duct and supplied to the introduction passage 15. Carbon dioxide, adjusted by a flow regulator from a carbon dioxide cylinder (manufactured by Iwatani Gas), is introduced into the aluminum flexible duct, and the carbon dioxide concentration of the raw gas (the gas to be treated sent to the introduction passage 15) is adjusted using a CO2 meter (HORIBA model VA-3000) to reach the set concentration. Once the carbon dioxide concentration stabilizes, the carbon dioxide concentration of the treated gas (the gas to be treated exhausted from the exhaust passage 23) is measured using the aforementioned CO2 meter, and the carbon dioxide removal rate is determined.

[0051] When air with a carbon dioxide concentration of 10,000 ppm was supplied to the intake passage 15, air with a carbon dioxide concentration of 2,770 ppm was discharged from the exhaust passage 23. Therefore, the reduction rate of carbon dioxide was 72%.

[0052] (Effects of the first embodiment) As described above, according to this embodiment, when a gas to be treated containing carbon dioxide is sent into the plasma processing path 10, plasma is generated in the gas to be treated, and at this time, carbon dioxide is ionized or excited. The gas to be treated, which contains the cations generated by the ionization of carbon dioxide and the excited carbon dioxide, is passed through the steel slag layer 24 of the adsorption processing path 20. Therefore, carbon dioxide can be removed without the need to supply moisture.

[0053] Furthermore, by applying voltage throughout the entire flow path between the cylindrical electrode 11 and the axial electrode 12, the gas to be processed can be turned into plasma and immediately sent to the adsorption processing path 20. This makes it easier to deliver the carbon dioxide contained in the gas to be processed to the steel slag layer in an ionized and excited state.

[0054] Furthermore, since the steel slag layer 24 is constructed by stacking multiple steel slags 24a, the steel slag layer 24 can be easily constructed.

[0055] (Second embodiment) The configuration of the carbon dioxide removal device 200 according to the second embodiment will be described with reference to Figure 2. Figure 2 is a front view showing the carbon dioxide removal device 200 according to the second embodiment. This embodiment differs from the first embodiment in the number of plasma processing paths 10 and adsorption processing paths 20, and this embodiment will be described focusing on the differences from the first embodiment. Components having substantially the same functional configuration are denoted by the same reference numerals, and redundant explanations will be omitted.

[0056] As shown in Figure 2, the carbon dioxide removal device 200 is configured by providing multiple sets of plasma processing paths 10 and adsorption processing paths 20 in series. In other words, multiple carbon dioxide removal devices 100 of the first embodiment are connected in series. The carbon dioxide removal device 200 consists of four carbon dioxide removal devices 100, with the processing path from the introduction path 31 of the upstream carbon dioxide removal device 100 to the exhaust path 32 of the downstream carbon dioxide removal device 100. These multiple carbon dioxide removal devices 100 are supported by a machine frame 33. Due to the series connection of these four carbon dioxide removal devices 100, the carbon dioxide removal device 200 is equipped with four plasma processing paths 10 and adsorption processing paths 20, with these plasma processing paths 10 and adsorption processing paths 20 arranged alternately from upstream to downstream. Therefore, carbon dioxide removal can be repeatedly performed multiple times (four times in the example shown in Figure 2) from the introduction path 31 of the upstream plasma processing path 10 to the exhaust path 32 of the downstream adsorption processing path 20.

[0057] The carbon dioxide removal method in the carbon dioxide removal device 200 involves repeatedly performing plasma treatment in the plasma treatment path 10 and adsorption treatment in the adsorption treatment path 20 alternately from upstream to downstream, gradually removing carbon dioxide from the gas to be treated. Therefore, a particularly high final carbon dioxide removal rate can be achieved.

[0058] Furthermore, the carbon dioxide concentration of the gas to be treated is highest when it is fed into the inlet path 31 of the upstream carbon dioxide removal device 100, and decreases as you move further downstream in the carbon dioxide removal device 100. Therefore, the further downstream in the carbon dioxide removal device 100 the probability of carbon dioxide being ionized and excited in the plasma treatment path 10 decreases, and the adsorption efficiency in the steel slag layer 24 of the adsorption treatment path 20 decreases. For this reason, if there are too many sets of plasma treatment paths 10 and adsorption treatment paths 20 connected in series, the increase in operating costs will not justify the improvement in the carbon dioxide removal rate. From an efficiency standpoint for improving the carbon dioxide removal rate, the number of sets of plasma treatment paths 10 and adsorption treatment paths 20 is preferably 3 to 4, and it is preferable to limit the number of sets to a saturation point where the carbon dioxide removal rate hardly improves.

[0059] (Effects of the second embodiment) As described above, according to this embodiment, the plasma treatment in the plasma treatment path 10 and the adsorption treatment in the adsorption treatment path 20 are repeated alternately multiple times from the upstream side to the downstream side, gradually removing carbon dioxide from the gas to be treated, thereby making it possible to achieve a particularly high final carbon dioxide removal rate.

[0060] Preferred embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these examples. It will be obvious to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0061] For example, in the first embodiment described above, the steel slag layer 24 was configured by stacking a plurality of steel slags 24a, but the present invention is not limited to this example. For example, the steel slag layer may be configured integrally in layers to match the shape of the adsorption processing path. The same applies to the second embodiment described above.

[0062] Furthermore, in the first embodiment described above, an example was shown in which the carbon dioxide removal device 100 is equipped with one plasma processing path 10 and one adsorption processing path 20, connected in series. However, the present invention is not limited to this example. It is not essential that the number of plasma processing paths and adsorption processing paths be the same; it is also possible to connect one or more plasma processing paths with multiple or one adsorption processing paths. The flow velocity preferred for plasma generation and the flow velocity preferred for adsorption in the steel slag layer do not necessarily coincide. If there is a large difference in these flow velocities, a difference in the number of plasma processing paths and adsorption processing paths can be provided to obtain an appropriate flow velocity in each processing path.

[0063] Furthermore, although the first embodiment described above shows an example in which the carbon dioxide removal device 100 is composed of one set of plasma processing paths 10 and adsorption processing paths 20, the present invention is not limited to this example. The carbon dioxide removal device may be configured to have multiple sets of plasma processing paths and adsorption processing paths in parallel to increase the processing capacity per unit time in a single carbon dioxide removal device.

[0064] The above embodiments, application examples, and modifications can be implemented in any combination. [Explanation of symbols]

[0065] 100, 200 carbon dioxide removal devices 10 Plasma processing path 11. Cylindrical electrode 12 Axial electrode 13 Insulating Spacer 14 channels 15, 31 Introductory path 20 Adsorption processing path 21 connecting routes 22 Adsorption pipe line 22a Breathable barrier 23, 32 Exhaust passages 24. Steel slag layer 24a Steel slag 24b Gap 33 machine frame

Claims

1. A plasma processing path that generates plasma in the gas to be processed flowing through the channel, An adsorption treatment path through which the gas to be treated, which has generated plasma, is introduced and passed through the steel slag layer, A carbon dioxide removal device characterized by comprising the following features.

2. The system comprises a plurality of plasma processing paths and a plurality of adsorption processing paths, The carbon dioxide removal apparatus according to claim 1, characterized in that the plasma processing path and the adsorption processing path are arranged alternately from the upstream side to the downstream side.

3. The flow path of the plasma processing path is formed between a cylindrical electrode and an axial electrode arranged coaxially inside the cylindrical electrode. A voltage is applied between the cylindrical electrode and the axial electrode, thereby generating plasma in the gas to be processed. The carbon dioxide removal apparatus according to claim 1 or 2, characterized in that the adsorption processing path is connected to the downstream side of the flow path of the plasma processing path.

4. The carbon dioxide removal apparatus according to claim 1 or 2, characterized in that the steel slag layer is formed by stacking a plurality of steel slags.

5. Plasma treatment involves generating plasma in a gas to be treated while flowing a gas containing carbon dioxide through it, The aforementioned plasma treatment generates plasma from the gas to be treated, which is then passed through the steel slag layer in an adsorption treatment. A method for removing carbon dioxide, characterized by performing the following.

6. The carbon dioxide removal method according to claim 5, characterized in that the plasma treatment and the adsorption treatment are repeated alternately multiple times from the upstream side to the downstream side.

7. The plasma treatment involves flowing the gas to be treated through a channel between a cylindrical electrode and an axial electrode coaxially arranged inside the cylindrical electrode, and applying a voltage between the cylindrical electrode and the axial electrode. The carbon dioxide removal method according to claim 5 or 6, characterized in that the adsorption treatment is a process of passing the gas to be treated, which has generated plasma, through the steel slag layer in a pipeline connected to the downstream side of the flow path.

8. The carbon dioxide removal method according to claim 5 or 6, characterized in that the steel slag layer is formed by stacking a plurality of steel slags.

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