Plasma reactor
The plasma reactor addresses the adhesion issue of CO2 adsorption materials by using layered or pellet-shaped adsorption members with specific surface area ratios, enhancing bonding and adsorption properties for efficient CO2 conversion to CO.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- DAIHATSU MOTOR CO LTD
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
AI Technical Summary
Carbon dioxide adsorption materials used in plasma reactors for converting CO2 to CO2 have poor adhesion to electrodes, leading to inferior durability.
A plasma reactor design with a carbon dioxide adsorption member comprising a first adsorption member made of CeO2, ZrO2, or their oxides with a smaller specific surface area, and a second adsorption member made of zeolite, CeO2, ZrO2, or Al2O3 with a larger specific surface area, both layered or pellet-shaped, enhancing bonding and adsorption properties.
The reactor achieves excellent bonding between the adsorption member and dielectric layer, and efficient CO2 adsorption, resulting in improved durability and CO2 conversion to CO.
Smart Images
Figure 2026113873000001_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to a plasma reactor. [Background technology]
[0002] In recent years, from a carbon neutrality perspective, the conversion of carbon dioxide to carbon monoxide has been considered. Carbon dioxide is found, for example, in factory exhaust gases. Carbon monoxide is used, for example, as a raw material for resins and fuels.
[0003] One known method for converting carbon dioxide to carbon monoxide is plasma treatment of carbon dioxide. More specifically, the following carbon monoxide production method has been proposed. This carbon monoxide production method includes the steps of generating plasma particles from a plasma particle generating source gas and generating a gas containing carbon monoxide by contacting the plasma particles with a carbon dioxide-containing source gas (see, for example, Patent Document 1 below). [Prior art documents] [Patent Documents]
[0004] [Patent Document 1] Japanese Patent Publication No. 2013-252987 [Overview of the Initiative] [Problems that the invention aims to solve]
[0005] Furthermore, in the carbon monoxide production system described above, a plasma reactor equipped with a carbon dioxide adsorption material is proposed as a method for efficiently converting carbon dioxide into carbon monoxide.
[0006] Specifically, a proposed solution involves installing the carbon dioxide adsorption material on an electrode consisting of a conductive layer and a dielectric layer.
[0007] On the other hand, carbon dioxide adsorption materials, while possessing excellent adsorption properties, have poor adhesion to electrodes (especially the dielectric layer), resulting in inferior durability.
[0008] The present invention relates to a plasma reactor that exhibits excellent bonding properties between the carbon dioxide adsorption member and the dielectric layer, as well as excellent carbon dioxide adsorption properties. [Means for solving the problem]
[0009] The present invention [1] is a plasma reactor that converts carbon dioxide to carbon monoxide, comprising a casing through which a gas containing carbon dioxide and / or carbon monoxide passes, and an electrode panel and a carbon dioxide adsorption member arranged in the casing in a direction perpendicular to the direction of gas passage, wherein the electrode panel comprises a conductive layer and a ceramic substrate disposed on the conductive layer, and the carbon dioxide adsorption member comprises a first adsorption member disposed on the electrode panel and a second adsorption member disposed on the first adsorption member, wherein the raw material of the first adsorption member contains at least one selected from the group consisting of CeO2, ZrO2, and oxides made of Ce and Zr, and the raw material of the second adsorption member contains at least one selected from the group consisting of zeolite, CeO2, ZrO2, Al2O3, and oxides made of Ce and Zr, and the specific surface area of the raw material of the first adsorption member is smaller than the specific surface area of the raw material of the second adsorption member.
[0010] In the plasma reactor described above, the carbon dioxide adsorption member comprises a first adsorption member placed on the electrode panel and a second adsorption member placed on the first adsorption member. Furthermore, the raw materials for the first adsorption member and the second adsorption member are made of predetermined materials. In addition, the specific surface area of the raw material for the first adsorption member is smaller than the specific surface area of the raw material for the second adsorption member. Therefore, the first adsorption member has excellent binding properties, and the second adsorption member has excellent adsorption properties. Moreover, the first adsorption member also has adsorption properties. Therefore, the carbon dioxide adsorption member has excellent binding properties with the dielectric layer and also excellent carbon dioxide adsorption properties.
[0011] The present invention [2] is such that the specific surface area of the raw material of the first adsorption member is 50 m 2 / g or less, and the specific surface area of the raw material of the second adsorption member is 100 m 2 / g or more, and includes the plasma reactor described in the above [1].
[0012] In the above plasma reactor, the specific surface area of the raw material of the first adsorption member is a predetermined value or less. Therefore, the first adsorption member is further excellent in binding property. Also, the specific surface area of the raw material of the second adsorption member is a predetermined value or more. Therefore, the second adsorption member is further excellent in adsorption property. Thereby, the carbon dioxide adsorption member is further excellent in the binding property with the dielectric layer and is also further excellent in carbon dioxide adsorption property.
[0013] The present invention [3] includes the plasma reactor according to any one of the above [1] and [2], in which the first adsorption member is formed in a layered shape and the second adsorption member is formed in a pellet shape.
[0014] In the above plasma reactor, the first adsorption member is formed in a layered shape and the second adsorption member is formed in a pellet shape. Therefore, the first adsorption member is further excellent in binding property, while the second adsorption member can have a large specific surface area and is further excellent in adsorption property. Thereby, the carbon dioxide adsorption member is further excellent in the binding property with the dielectric layer and is also further excellent in carbon dioxide adsorption property.
Advantages of the Invention
[0015] The plasma reactor of the present invention is excellent in the binding property between the carbon dioxide adsorption member and the dielectric layer and is also excellent in carbon dioxide adsorption property.
Brief Description of the Drawings
[0016] [Figure 1] FIG. 1 is a schematic diagram showing an embodiment of a plasma reactor device including the plasma reactor of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing an embodiment of the electrode unit shown in FIG. 1. [Figure 3]FIG. 3 is a schematic diagram showing a modified example of the electrode unit shown in FIG. 2. [Figure 4] FIG. 4 is a schematic diagram showing a modified example of the plasma reactor device including the plasma reactor shown in FIG. 1.
Embodiments for Carrying Out the Invention
[0017] Hereinafter, an embodiment of the present invention will be described in detail.
[0018] 1. Plasma Reactor Device (1) Overall Configuration The plasma reactor device converts carbon dioxide into carbon monoxide. More specifically, the plasma reactor device passes a gas containing carbon dioxide (untreated gas) in a predetermined direction, subjects the carbon dioxide to plasma treatment, and produces a gas containing carbon monoxide (treated gas). Hereinafter, the passing directions of the untreated gas and the treated gas will be referred to as the gas passing direction.
[0019] An embodiment of the plasma reactor device will be described in detail with reference to FIG. 1.
[0020] In FIG. 1, the plasma reactor device 1 includes a plasma reactor 2, a carbon dioxide supply line 3, a carbon monoxide discharge line 4, a power supply unit 5, and a control unit 6.
[0021] The plasma reactor 2 is a device that generates plasma and converts carbon dioxide into carbon monoxide. The plasma reactor 2 includes a casing 20 and a plurality of electrode units 21 disposed within the casing 20.
[0022] The casing 20 has a hollow cylindrical shape. The casing 20 is positioned so that its longitudinal direction is aligned with the gas passage direction. A gas supply port is formed in the side wall of the casing 20 on the upstream side (right side of the page) in the gas passage direction. The gas supply port is connected to the carbon dioxide supply line 3. A gas outlet is formed in the side wall of the casing 20 on the downstream side (left side of the page) in the gas passage direction. The gas outlet is connected to the carbon monoxide discharge line 4. In other words, gas containing carbon dioxide and / or carbon monoxide passes through the casing 20.
[0023] Each of the multiple electrode units 21 is arranged at intervals from one another along a direction perpendicular to the longitudinal direction (gas passage direction) of the casing 20. Furthermore, each of the multiple electrode units 21 is arranged within the casing 20 along the longitudinal direction (gas passage direction) of the casing 20. The number of electrode units 21 is not particularly limited. In Figure 1, three electrode units 21 are arranged within the casing 20.
[0024] Each of the multiple electrode units 21 comprises an electrode panel 22 and a carbon dioxide adsorption member 25, as shown in Figure 2. In other words, the electrode panel 22 and the carbon dioxide adsorption member 25 are arranged within the casing 20 in a direction perpendicular to the gas passage direction.
[0025] The electrode panel 22 has a thin plate shape. The electrode panel 22 comprises a conductor layer 23 and a dielectric layer 24.
[0026] The conductor layer 23 contains a metallic material, preferably a metallic material. Examples of metallic materials include tungsten. The shape of the conductor layer 23 is not particularly limited. For example, the conductor layer 23 may have a thin plate shape. The size of the conductor layer 23 is also not particularly limited and can be set appropriately according to the purpose and application. The conductor layer 23 is electrically connected to the power supply unit 5 (described later) (see dashed line in Figure 1). As a result, the conductor layer 23 receives power from the power supply unit 5 (described later).
[0027] The dielectric layer 24 is placed on top of the conductive layer 23. Specifically, the dielectric layer 24 covers the conductive layer 23. For example, if the conductive layer 23 has a thin plate shape, the dielectric layer 24 covers both the front and back surfaces of the conductive layer 23.
[0028] The dielectric layer 24 includes, for example, a dielectric material, and preferably consists of a dielectric material. Examples of dielectric materials include plastics, glass, and ceramics, with ceramics being preferred. In other words, the dielectric layer 24 is preferably a ceramic substrate. Examples of ceramics include barium titanate, forsterite, aluminum oxide, and titanium oxide. The size of the dielectric layer 24 is not particularly limited and can be set appropriately according to the purpose and application.
[0029] The carbon dioxide adsorption member 25 covers the electrode panel 22. More specifically, the carbon dioxide adsorption member 25 is laminated on both the front and back surfaces of the electrode panel 22.
[0030] The carbon dioxide adsorption member 25 comprises a first adsorption member 26 and a second adsorption member 27.
[0031] The first adsorption member 26 is placed on the electrode panel 22. More specifically, the first adsorption member 26 is laminated on the front and back surfaces of the electrode panel 22.
[0032] The second suction member 27 is placed on the first suction member 26. More specifically, the second suction member 27 is laminated on the front and back surfaces of the first suction member 26.
[0033] In other words, each of the multiple electrode units 21 has a dielectric layer 24, a first adsorption member 26, and a second adsorption member 27 arranged in order on the front and back surfaces of the conductor layer 23, respectively.
[0034] The first adsorption member 26 and the second adsorption member 27 are molded articles obtained by firing a raw material in layers. That is, the first adsorption member 26 and the second adsorption member 27 are fired bodies and are molded in layers.
[0035] If the first adsorption member 26 and the second adsorption member 27 are fired bodies, the first adsorption member 26 is further excellent in binding property, and the second adsorption member 27 is further excellent in adsorption property. Thereby, the carbon dioxide adsorption member 25 is further excellent in binding property with the dielectric layer 24 and is also further excellent in carbon dioxide adsorption property. Also, even if the first adsorption member 26 and the second adsorption member 27 are layered, the first adsorption member 26 is further excellent in binding property, and the second adsorption member 27 is further excellent in adsorption property. Thereby, the carbon dioxide adsorption member 25 is further excellent in binding property with the dielectric layer 24 and is also further excellent in carbon dioxide adsorption property.
[0036] The raw material of the first adsorption member 26 contains at least one selected from the group consisting of CeO2, ZrO2, and an oxide composed of Ce and Zr. The raw material of the first adsorption member 26 preferably consists of CeO2.
[0037] The specific surface area of the raw material of the first adsorption member 26 is, for example, 70 m 2 / g or less, preferably 60 m 2 / g or less, more preferably 50 m 2 / g or less, and particularly preferably 40 m 2 / g or less. The specific surface area of the raw material of the first adsorption member 26 is, for example, 10 m 2 / g or more, preferably 20 m 2 / g or more, more preferably 30 m 2 / g or more. The specific surface area can be measured by the BET-SSA method (the same applies hereinafter).
[0038] If the specific surface area of the raw material of the first adsorption member 26 is below the above upper limit, the carbon dioxide adsorption member 25 is excellent in binding property with the dielectric layer 24.
[0039] The raw material for the second adsorbent member 27 contains at least one selected from the group consisting of zeolite, CeO2, ZrO2, Al2O3, and oxides composed of Ce and Zr. Examples of zeolites include natural zeolites and artificial zeolites. Examples of natural zeolites include borolite, mordenite, and clinoptilolite. Examples of artificial zeolites include hydrophilic zeolites with a low silica content and hydrophobic zeolites with a high silica content. Examples of hydrophilic zeolites include X-type (13X) zeolite and A-type zeolite. Preferably, hydrophilic zeolites are used, and more preferably, X-type zeolites are used. The raw material for the second adsorbent member preferably consists of zeolites.
[0040] The specific surface area of the raw material of the second adsorption member 27 is, for example, 80 m². 2 It is 100m or more / g, preferably 100m 2 It is 300m or more, and more preferably 300m 2 It is 1 / g or more, and more preferably 600m 2 It is 1 / g or more, and particularly preferably 800m 2 It is 1500 m² or more. The specific surface area of the raw material of the second adsorption member 27 is, for example, 1500 m². 2 It is less than or equal to / g, preferably 1200m 2 It is less than or equal to / g, and more preferably 900m 2 It is less than / g.
[0041] If the specific surface area of the raw material of the second adsorption member 27 is equal to or greater than the above lower limit, the carbon dioxide adsorption member 25 exhibits excellent carbon dioxide adsorption properties.
[0042] In other words, if the specific surface area of the raw material of the first adsorption member 26 is less than or equal to the upper limit, and the specific surface area of the raw material of the second adsorption member 27 is greater than or equal to the lower limit, the carbon dioxide adsorption member 25 will have even better bonding properties with the dielectric layer 24 and even better carbon dioxide adsorption properties.
[0043] The specific surface area of the raw material of the first adsorption member 26 is smaller than the specific surface area of the raw material of the second adsorption member 27. If the specific surface area of the raw material of the first adsorption member 26 is smaller than the specific surface area of the raw material of the second adsorption member 27, the carbon dioxide adsorption member 25 will have excellent bonding properties with the dielectric layer 24 and also excellent carbon dioxide adsorption properties.
[0044] Conversely, if the specific surface area of the raw material of the first adsorption member 26 is larger than the specific surface area of the raw material of the second adsorption member 27, the carbon dioxide adsorption member 25 will have poor bonding properties with the dielectric layer 24.
[0045] The ratio of the specific surface area of the raw material of the second adsorbent member 27 to the specific surface area of the raw material of the first adsorbent member 26 (specific surface area of the raw material of the second adsorbent member 27 / specific surface area of the raw material of the first adsorbent member 26) is, for example, 2 or more, preferably 5 or more, more preferably 10 or more, and particularly preferably 15 or more. The ratio of the specific surface area of the raw material of the second adsorbent member 27 to the specific surface area of the raw material of the first adsorbent member 26 (specific surface area of the raw material of the second adsorbent member 27 / specific surface area of the raw material of the first adsorbent member 26) is, for example, 150 or less, preferably 60 or less, more preferably 40 or less, and particularly preferably 25 or less.
[0046] The ratio of the second adsorption member 27 to the total amount of the first adsorption member 26 and the second adsorption member 27 is, for example, 65% by mass or more, preferably 70% by mass or more, more preferably 75% by mass or more, and particularly preferably 80% by mass or more. The ratio of the second adsorption member 27 to the total amount of the first adsorption member 26 and the second adsorption member 27 is, for example, 85% by mass or less.
[0047] If the ratio of the second adsorbent member 27 to the total amount of the first adsorbent member 26 and the second adsorbent member 27 is within the above range, the balance between the bonding properties with the dielectric layer 24 and the carbon dioxide adsorption properties of the carbon dioxide adsorbent member 25 can be appropriately maintained.
[0048] The raw materials for the first adsorption member 26 and the second adsorption member 27 may support metals. Examples of metals that can be supported include alkali metals and alkaline earth metals. Examples of alkali metals include Li, Na, K, Rb, and Cs, with Na and K being preferred. Examples of alkaline earth metals include Be, Mg, Ca, Sr, and Ba, with Sr being preferred. It is preferable to support the metal in the raw material of the second adsorption member 27, and further, if the raw material of the second adsorption member 27 is made of CeO2, it is preferable to support an alkaline earth metal, and if the raw material of the second adsorption member 27 is made of Al2O3, it is preferable to support an alkali metal. Known methods can be used for supporting the metal. The amount of metal supported can be adjusted as appropriate.
[0049] The raw materials for the carbon dioxide adsorption member 25 may contain zeolite and raw materials other than CeO2, ZrO2, Al2O3, and oxides composed of Ce and Zr (hereinafter referred to as "other raw materials"). The other raw materials can be used alone or in combination of two or more types. The content ratio of the other raw materials is set appropriately within a range that does not hinder the excellent effects of the present invention.
[0050] Preferably, the raw material for the carbon dioxide adsorption member 25 does not contain any other raw materials. That is, the raw material for the first adsorption member 26 consists of at least one selected from the group consisting of CeO2, ZrO2, and oxides made of Ce and Zr, and the raw material for the second adsorption member 27 consists of at least one selected from the group consisting of zeolite, CeO2, ZrO2, Al2O3, and oxides made of Ce and Zr. The raw material for the first adsorption member 26 is more preferably CeO2. The raw material for the second adsorption member 27 is more preferably zeolite.
[0051] The first adsorption member 26 and the second adsorption member 27 are manufactured, for example, by the following method. A slurry containing the raw materials for the first adsorption member 26 (CeO2, ZrO2, and oxides composed of Ce and Zr) is applied to the electrode panel 22 (dielectric layer 24) and dried. Then, a slurry containing the raw materials for the second adsorption member 27 (zeolite, CeO2, ZrO2, Al2O3, and oxides composed of Ce and Zr) is applied and dried. Finally, the coating film is fired. As a result, layered first adsorption member 26 and second adsorption member 27, made of the above raw materials, are sequentially formed on the surface of the electrode panel 22 as fired coating films. The size (thickness) of the carbon dioxide adsorption member 25 is not particularly limited and can be set appropriately according to the purpose and application.
[0052] The plasma reactor 2 is further equipped with a carbon dioxide adsorption amount sensor 28, if necessary.
[0053] The carbon dioxide adsorption amount sensor 28 is, for example, placed inside the casing 20 and detects the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 25.
[0054] The carbon dioxide adsorption amount sensor 28 is not particularly limited, and any known sensor can be used. The carbon dioxide adsorption amount sensor 28 is electrically connected to the control unit 6 (described later) (see dashed line in Figure 1). This allows the carbon dioxide adsorption amount sensor 28 to input the amount of carbon dioxide adsorbed as an electrical signal to the control unit 6 (described later).
[0055] The carbon dioxide supply line 3 is provided to supply carbon dioxide to the plasma reactor 2. The carbon dioxide supply line 3 includes, for example, a carbon dioxide supply pipe 30.
[0056] The carbon dioxide supply pipe 30 is a pipe for supplying carbon dioxide to the plasma reactor 2. The upstream end (right side of the page) of the carbon dioxide supply pipe 30 in the gas passage direction is connected to a carbon dioxide supply source (not shown). The downstream end (left side of the page) of the carbon dioxide supply pipe 30 in the gas passage direction is connected to the gas supply port on the upstream side (right side of the page) of the casing 20 in the gas passage direction.
[0057] The sources of carbon dioxide (not shown) are not particularly limited. Examples of carbon dioxide sources include various factory equipment and carbon dioxide storage tanks.
[0058] The carbon dioxide supply line 3 may be equipped with an on-off valve (not shown) and / or a pump (not shown) as needed. The on-off valve (not shown) and / or pump (not shown) may be interposed, for example, in a portion of the carbon dioxide supply pipe 30 in the direction of passage.
[0059] The carbon monoxide exhaust line 4 is provided to discharge carbon monoxide from the plasma reactor 2. The carbon monoxide exhaust line 4 includes, for example, a carbon monoxide exhaust pipe 40.
[0060] The carbon monoxide exhaust pipe 40 is a pipe for exhausting carbon monoxide from the plasma reactor 2. The upstream side of the carbon monoxide exhaust pipe 40 in the gas passage direction (right side of the paper) is connected to the gas outlet on the downstream side of the casing 20 in the gas passage direction (left side of the paper). The downstream end of the carbon monoxide exhaust pipe 40 in the gas passage direction (left side of the paper) is connected to a carbon monoxide supply destination (not shown).
[0061] The destination of the carbon monoxide (not shown) is not particularly limited. Examples of carbon monoxide destinations include resin manufacturing facilities, fuel manufacturing facilities, and carbon monoxide storage tanks.
[0062] The carbon monoxide discharge line 4 may be equipped with a shut-off valve (not shown) and / or a pump (not shown) as needed. The shut-off valve (not shown) and / or pump (not shown) may be interposed, for example, in a portion of the carbon monoxide discharge pipe 40 in the direction of passage.
[0063] The power supply unit 5 is a unit that supplies (applies) power (voltage) to the plasma reactor 2. Examples of the power supply unit 5 include a DC power supply unit, an AC power supply unit, and a pulse power supply unit. The power supply unit 5 is preferably a pulse power supply unit.
[0064] The power supply unit 5 is electrically connected to each of the multiple electrode units 21 of the plasma reactor 2 (see dashed lines in Figure 1). This allows the power supply unit 5 to supply power to the plasma reactor 2 and generate plasma between the electrode units 21.
[0065] Furthermore, the power supply unit 5 is electrically connected to the control unit 6 (see dashed line in Figure 1). As a result, the operation and shutdown of the power supply unit 5 are electrically controlled by the control unit 6.
[0066] The control unit 6 is a unit that electrically controls the power supply unit 5. The control unit 6 is, for example, a microcomputer. The control unit 6 includes, for example, memory and a central processing unit (CPU). The memory includes ROM and RAM. The ROM stores various programs and fixed data. The RAM stores temporary input data. The central processing unit (CPU) operates and stops the power supply unit 5 based on various programs. In this way, the control unit 6 controls the plasma reactor 2.
[0067] Furthermore, the control unit 6 is electrically connected to the carbon dioxide adsorption amount sensor 28 (see dashed line in Figure 1). This allows the control unit 6 to control the plasma reactor 2 according to the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 25.
[0068] (2) Operation of the plasma reactor In the plasma reactor apparatus 1 described above, carbon dioxide is first supplied to the plasma reactor 2. More specifically, an untreated gas containing carbon dioxide and a carrier (such as air) is discharged from a carbon dioxide supply source (not shown). The untreated gas is supplied to the plasma reactor 2 via the carbon dioxide supply line 3.
[0069] The carbon dioxide concentration in the untreated gas is, for example, 100 ppm or more, preferably 300 ppm or more. Alternatively, the carbon dioxide concentration in the untreated gas is, for example, 10,000 ppm or less, preferably 5,000 ppm or less.
[0070] The supply flow rate of the untreated gas is set according to the size and performance of the plasma reactor 2. The supply flow rate of the untreated gas is, for example, 0.1 L / min, preferably 0.5 L / min. The supply flow rate of carbon dioxide is, for example, 20 L / min, preferably 10 L / min.
[0071] Carbon dioxide in the untreated gas is adsorbed onto the carbon dioxide adsorption member 25 within the plasma reactor 2. Then, the carbon dioxide adsorbed onto the carbon dioxide adsorption member 25 is subjected to plasma treatment in the plasma reactor device 1.
[0072] More specifically, in this method, the power supply unit 5 is operated by the control unit 6, and power is supplied to the plasma reactor 2. This generates plasma between the electrode units 21. Then, the carbon dioxide adsorbed on the carbon dioxide adsorption member 25 is decomposed by the plasma, producing carbon monoxide. The magnitude of the power supplied to the plasma reactor 2 (applied power) and the power frequency of the plasma reactor 2 are not particularly limited and are set according to the purpose and application.
[0073] Carbon monoxide is discharged from the plasma reactor 2 via the carbon monoxide discharge line 4. More specifically, the gas to be treated, which includes carbon monoxide and a carrier (such as air), is discharged from the plasma reactor 2. After being discharged from the plasma reactor 2, the gas to be treated is supplied to a carbon monoxide supply destination (not shown) via the carbon monoxide discharge line 4.
[0074] The carbon monoxide concentration in the gas to be treated is, for example, 100 ppm or more, preferably 300 ppm or more. Alternatively, the carbon monoxide concentration in the gas to be treated is, for example, 10,000 ppm or less, preferably 5,000 ppm or less.
[0075] As described above, the plasma reactor device 1 can convert carbon dioxide into carbon monoxide by adsorbing carbon dioxide onto the carbon dioxide adsorption member 25.
[0076] In the plasma reactor device 1 described above, the timing of operation and shutdown of the plasma reactor 2 is set appropriately according to the purpose and application.
[0077] For example, the plasma reactor 2 may be activated according to the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 25.
[0078] More specifically, in this method, a threshold for the amount of carbon dioxide adsorbed to activate the plasma reactor 2 is set in advance. The threshold for the amount of carbon dioxide adsorbed is set appropriately according to the size and performance of the plasma reactor 2.
[0079] The threshold for carbon dioxide adsorption is, for example, 50-100% of the maximum (limit) amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 25.
[0080] In this method, the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 25 is detected by the carbon dioxide adsorption amount sensor 28. The amount of carbon dioxide adsorbed is also input as an electrical signal to the control unit 6.
[0081] The control unit 6 determines whether the amount of carbon dioxide adsorbed is above a predetermined threshold. As long as the amount of carbon dioxide adsorbed is below the predetermined threshold, the plasma reactor 2 is stopped. On the other hand, when the amount of carbon dioxide adsorbed is above the predetermined threshold, the power supply unit 5 is activated by the control unit 6, and power is supplied to the plasma reactor 2. Operating the plasma reactor 2 in this way allows for more efficient production of carbon monoxide.
[0082] <Effects of this embodiment> In the plasma reactor 2 described above, the carbon dioxide adsorption member 25 comprises a first adsorption member 26 and a second adsorption member 27. The first adsorption member 26 has excellent binding properties as well as adsorption properties. The second adsorption member 27 also has excellent adsorption properties. Therefore, the plasma reactor 2 described above has excellent binding properties between the carbon dioxide adsorption member 25 and the dielectric layer 24, as well as excellent carbon dioxide adsorption properties.
[0083] In particular, in the plasma reactor 2 described above, the specific surface area of the raw material for the first adsorption member 26 is smaller than the specific surface area of the raw material for the second adsorption member 27. Therefore, the first adsorption member 26 has better bonding properties with the dielectric layer 24 than the second adsorption member 27. Furthermore, the raw material for the first adsorption member 26 contains at least one selected from the group consisting of CeO2, ZrO2, and oxides composed of Ce and Zr. Therefore, the first adsorption member 26 also has carbon dioxide adsorption properties. In addition, the specific surface area of the raw material for the second adsorption member 27 is larger than the specific surface area of the raw material for the first adsorption member 26. Therefore, the second adsorption member 27 has better carbon dioxide adsorption properties than the first adsorption member 26. Furthermore, the raw material for the second adsorption member 27 contains at least one selected from the group consisting of zeolite, CeO2, ZrO2, Al2O3, and oxides composed of Ce and Zr. Therefore, the second adsorption member 27 has excellent carbon dioxide adsorption properties. The carbon dioxide adsorption member 25, consisting of the first adsorption member 26 and the second adsorption member 27, exhibits excellent bonding properties with the dielectric layer 24, as well as excellent carbon dioxide adsorption properties. As a result, the plasma reactor 2 exhibits excellent bonding properties between the carbon dioxide adsorption member 25 and the dielectric layer 24, as well as excellent carbon dioxide adsorption properties.
[0084] 2. Variation 1 Although the carbon dioxide adsorption member 25 described above covers both sides of the electrode panel 22, it may also cover only the surface of the electrode panel 22. More specifically, the carbon dioxide adsorption member 25 may be laminated on the dielectric layer 24 only on the surface of the electrode panel 22.
[0085] 3. Variation 2 The second adsorption member 27 described above may be molded into a pellet shape, as shown in Figure 3. That is, the first adsorption member 26 may be molded in layers, and the second adsorption member 27 may be molded into a pellet shape.
[0086] In this case, the first adsorption member 26 and the second adsorption member 27 are manufactured, for example, by the following method. A slurry containing the raw materials for the first adsorption member 26 (CeO2, ZrO2, and oxides consisting of Ce and Zr) is applied to the electrode panel 22 (dielectric layer 24). Then, the raw materials for the second adsorption member 27 (zeolite, CeO2, ZrO2, Al2O3, and oxides consisting of Ce and Zr), which have been formed into pellets, are attached to the coating. After that, the coating and pellets are fired. As a result, a layered first adsorption member 26 and a pellet-shaped second adsorption member 27, made of the above raw materials, are sequentially formed on the surface of the dielectric layer 24 as a fired body of the coating and pellets.
[0087] The method for obtaining the raw material for the pelletized second adsorption member 27 is not particularly limited, and known methods can be employed. The raw material for the second adsorption member 27 can also be obtained as a commercially available product.
[0088] If the first adsorption member 26 is in a layered form, it exhibits superior bonding properties with the dielectric layer 24. Furthermore, if the second adsorption member 27 is in a pellet form, its specific surface area can be increased, resulting in even greater adsorption properties. As a result, the carbon dioxide adsorption member 25 exhibits even greater bonding properties with the dielectric layer 24, as well as even greater carbon dioxide adsorption properties.
[0089] 4. Variation 3 The plasma reactor device 1 described above may be equipped with two or more plasma reactors 2. Furthermore, the plasma reactor device 1 may selectively use any of the two or more plasma reactors 2.
[0090] (1) Overall structure A modified example of the plasma reactor device 1 will be described in detail below with reference to Figure 4.
[0091] In Figure 4, the plasma reactor device 1 comprises a plasma reactor 2, a carbon dioxide supply line 3, a carbon monoxide emission line 4, the power supply unit 5 described above, and the control unit 6 described above.
[0092] The plasma reactor 2 comprises a first plasma reactor 2A and a second plasma reactor 2B.
[0093] The first plasma reactor 2A and the second plasma reactor 2B each have the same configuration as the plasma reactor 2 shown in Figure 1.
[0094] In Figure 4, the carbon dioxide supply line 3 comprises a supply-side main pipe 35, a supply-side first pipe 31, a supply-side second pipe 32, and a supply-side three-way valve 33.
[0095] In Figure 4, the carbon monoxide discharge line 4 comprises a first discharge pipe 41, a second discharge pipe 42, and a main discharge pipe 45.
[0096] (2) Operation of the plasma reactor In the plasma reactor device 1 described above, the opening and closing of the supply-side three-way valve 33 is controlled by the control unit 6, and carbon dioxide is selectively supplied to either the first plasma reactor 2A or the second plasma reactor 2B.
[0097] For example, first, the supply-side three-way valve 33 is controlled by the control unit 6, and carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) to the first plasma reactor 2A via the supply-side main pipe 35 and the supply-side first pipe 31. The supplied carbon dioxide is then adsorbed by the carbon dioxide adsorption member in the first plasma reactor 2A.
[0098] Then, if the amount of carbon dioxide adsorbed by the first plasma reactor 2A exceeds a predetermined value, the supply-side three-way valve 33 is switched. At the same time, power is supplied to the first plasma reactor 2A, and the power supply to the second plasma reactor 2B is stopped.
[0099] As a result, plasma is generated between the electrode units of the first plasma reactor 2A. Then, the carbon dioxide adsorbed on the first plasma reactor 2A is decomposed by the plasma, producing carbon monoxide.
[0100] Carbon monoxide is discharged from the first plasma reactor 2A. After being discharged from the first plasma reactor 2A, the carbon monoxide is supplied to a carbon monoxide supply destination (not shown) via the discharge-side first pipe 41 and the discharge-side main pipe 45.
[0101] In addition, carbon dioxide is supplied to the second plasma reactor 2B from a carbon dioxide supply source (not shown) via the supply-side main pipe 35 and the supply-side second pipe 32. The carbon dioxide is then adsorbed onto the carbon dioxide adsorption member inside the second plasma reactor 2B.
[0102] Subsequently, the same operation as described above is performed in the second plasma reactor 2B to generate carbon monoxide. After being discharged from the second plasma reactor 2B, the carbon monoxide is supplied to a carbon monoxide supply destination (not shown) via the discharge-side second pipe 42 and the discharge-side main pipe 45.
[0103] In this manner, when the first plasma reactor 2A adsorbs carbon dioxide, the second plasma reactor 2B converts the carbon dioxide into carbon monoxide. Conversely, when the second plasma reactor 2B adsorbs carbon dioxide, the first plasma reactor 2A converts the carbon dioxide into carbon monoxide. Therefore, according to the plasma reactor apparatus 1 described above, a continuously supplied supply of carbon dioxide can be converted into carbon monoxide. As a result, according to the plasma reactor apparatus 1 described above, carbon monoxide can be continuously produced with excellent efficiency.
[0104] The number of plasma reactors 2 is not particularly limited; for example, there may be three or more.
[0105] Furthermore, in the above modified example, the control unit 6 controls based on the amount of carbon dioxide adsorbed, but it can also control based on a preset time interval, for example.
[0106] Furthermore, in the above modified example, the control unit 6 selectively controls the first plasma reactor 2A and the second plasma reactor 2B by switching the supply-side three-way valve 33. However, for example, the control unit 6 can also selectively control the first plasma reactor 2A and the second plasma reactor 2B by swapping their positions using a known rotating member. [Examples]
[0107] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass. Furthermore, specific numerical values such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values defined as "less than or equal to" or "less than") or lower limits (numerical values defined as "greater than or equal to" or "greater than") of the blending ratios (content), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.
[0108] Preparation of raw materials for carbon dioxide adsorption materials Preparation Example 1 (CeO2) Commercially available CeO2 (specific surface area: 38 m²) 2 / g, or 110m 2 We prepared ( / g, manufactured by Anan Kasei Co., Ltd.).
[0109] Preparation Example 2 (Zeolite) Commercially available powdered X-type zeolite (specific surface area: 819 m²) 2 I prepared a / g (model number F-9, manufactured by Tosoh Corporation).
[0110] Preparation Example 3 (Zeolite) Commercially available pelletized zeolite (specific surface area: 819 m²) 2 I prepared a / g (model number F-9HA, manufactured by Tosoh Corporation).
[0111] Example 1 The electrode unit was manufactured using the following method. First, 1.0 g of powdered CeO2 was dispersed in 1-2 g of a 0.1% by mass aqueous solution of a thickening agent to obtain a CeO2 slurry. The CeO2 slurry was applied to the surface of the electrode panel and dried at 100°C for 10 minutes. Next, 2.0 g of powdered zeolite was dispersed in 1-2 g of a 0.1% by mass aqueous solution of a thickening agent to obtain a zeolite slurry. The zeolite slurry was applied on top of the CeO2 coating film and dried at 100°C for 10 minutes, then fired at 500°C for 2 hours. As a result, a first adsorbent made of layered CeO2 and a second adsorbent made of layered zeolite were sequentially laminated on the electrode panel.
[0112] In Example 1, the ratio of the second adsorbent to the total amount of the first adsorbent and the second adsorbent (the mixing ratio of the first adsorbent and the second adsorbent) was 80% by mass (20:80).
[0113] Next, multiple electrode units were fabricated and set in the plasma reactor shown in Figure 1. Thus, the plasma reactor shown in Figure 1 was prepared.
[0114] Example 2 The electrode unit was manufactured using the following method. First, 1.0 g of powdered CeO2 was dispersed in 1-2 g of a 0.1% by mass thickening agent aqueous solution to obtain a CeO2 slurry. After applying the CeO2 slurry to the surface of the electrode panel, 2.0 g of pelletized zeolite was attached to the CeO2 coating. Next, the coating and pellets were dried at 100°C for 10 minutes, and then fired at 500°C for 2 hours. As a result, a first adsorbent made of CeO2 formed in layers and a second adsorbent made of zeolite formed in pellet form were laminated on the electrode panel.
[0115] In Example 2, the ratio of the second adsorbent to the total amount of the first adsorbent and the second adsorbent (the mixing ratio of the first adsorbent and the second adsorbent) was set to 70% by mass (30:70).
[0116] Next, multiple electrode units were fabricated and set in the plasma reactor shown in Figure 1. Thus, the plasma reactor shown in Figure 1 was prepared.
[0117] Comparative Examples 1-3 1.0 g of powdered CeO2 or 1.0 g of zeolite was dispersed in 1-2 g of a 0.1% by mass aqueous solution of a thickening agent to obtain a CeO2 or zeolite slurry. Next, the CeO2 or zeolite slurry was applied to the surface of an electrode panel, dried at 100°C for 10 minutes, and then calcined at 500°C for 2 hours.
[0118] The following aspects were evaluated in each example and comparative example. The results are shown in Table 1.
[0119] <Bonding properties between electrode panels and carbon dioxide adsorption material> The ability to maintain adhesion between the electrode panel (ceramic substrate) and the carbon dioxide adsorption member in each example and comparative example was evaluated. Specifically, after fabricating the carbon dioxide adsorption members for each example and comparative example on the ceramic substrate, the following three operations were performed: (1) rotating the electrode panel up, down, left, and right; (2) lightly flicking the electrode panel with a finger to apply impact; and (3) tracing the surface of the electrode panel with a finger. A circle (○) was used if the carbon dioxide adsorption member maintained adhesion to the electrode panel (ceramic substrate), and a cross (×) was used if it did not.
[0120] <Carbon dioxide adsorption amount> Based on the amount of carbon dioxide adsorbed by the raw materials of the following carbon dioxide adsorbent materials, as measured by thermogravimetric analysis, the amount of carbon dioxide adsorbed by each carbon dioxide adsorbent material was calculated from the mixing ratio of the first adsorbent material and the second adsorbent material of each carbon dioxide adsorbent material. Zeolite: 4 mmol / g CeO2 (specific surface area: 110m2 ( / g): 0.63 mmol / g CeO2 (specific surface area: 38m 2 ( / g): 0.23 mmol / g
[0121] [Table 1] [Explanation of Symbols]
[0122] 2 Plasma Reactor 20 Casing 22-electrode panel 23 Conductor layer 24 Dielectric layer 25 Carbon dioxide adsorption material 26 First adsorption member 27 Second Adsorption Member
Claims
1. This is a plasma reactor that converts carbon dioxide into carbon monoxide. A casing through which a gas containing carbon dioxide and / or carbon monoxide passes, Within the casing, the casing comprises electrode panels and carbon dioxide adsorption members arranged in a direction perpendicular to the gas passage direction, The electrode panel is Conductor layer, The conductor layer comprises a ceramic substrate disposed on the conductor layer, The carbon dioxide adsorption member is A first adsorption member is placed on the electrode panel, The device comprises a second adsorption member disposed on the first adsorption member, The raw material for the first adsorption member is CeO ２ And, ZrO ２ It contains at least one selected from the group consisting of an oxide made of Ce and Zr, The raw materials for the second adsorbent are zeolite and CeO ２ And, ZrO ２ And, Al ２ O ３ It contains at least one selected from the group consisting of an oxide made of Ce and Zr, A plasma reactor in which the specific surface area of the raw material of the first adsorption member is smaller than the specific surface area of the raw material of the second adsorption member.
2. The specific surface area of the raw material of the first adsorption member is 50 m². ２ / g or less, The specific surface area of the raw material of the second adsorption member is 100 m². ２ The plasma reactor according to claim 1, wherein the amount is 1g or more.
3. The first adsorption member is formed in layers, The plasma reactor according to claim 1, wherein the second adsorption member is formed into a pellet shape.