Carbon monoxide production system

Abstract

To provide a carbon monoxide production system capable of more efficiently producing carbon monoxide from carbon dioxide.SOLUTION: A carbon monoxide production system 1 converts carbon dioxide to carbon monoxide. The carbon monoxide production system 1 comprises a plasma reactor 3, a carbon dioxide feed line 4 for feeding carbon dioxide to the plasma reactor 3, and a carbon monoxide discharge line 5 for discharging carbon monoxide from the plasma reactor 3. The plasma reactor 3 comprises a casing 30, and a plurality of electrode panels 31 and carbon dioxide adsorption members 35 disposed in the casing 30.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD

[0001] The present invention relates to a carbon monoxide production system. BACKGROUND ART

[0002] In recent years, from the perspective of carbon neutrality, conversion of carbon dioxide to carbon monoxide has been investigated. Carbon dioxide is contained in, for example, exhaust gas from factories. Carbon monoxide is used as, for example, a resin raw material and a fuel raw material.

[0003] As a method for converting carbon dioxide to carbon monoxide, for example, a method of subjecting carbon dioxide to plasma treatment is known. More specifically, the following method for producing carbon monoxide has been proposed. This method for producing carbon monoxide includes a step of generating plasma particles from a plasma particle generating source gas, and a step of bringing the plasma particles into contact with a carbon dioxide-containing source gas to generate a gas containing carbon monoxide (see, for example, Patent Document 1 below). PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] PATENT DOCUMENT 1 Japanese Unexamined Patent Publication No. 2013-252987 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0005] On the other hand, in the production of carbon monoxide, efficient conversion of carbon dioxide to carbon monoxide is required.

[0006] The present invention is a carbon monoxide production system that can produce carbon monoxide from carbon dioxide more efficiently. MEANS FOR SOLVING THE PROBLEM

[0007] The present invention [1] is a carbon monoxide production system that converts carbon dioxide into carbon monoxide, comprising a plasma reactor, a carbon dioxide supply line for supplying carbon dioxide to the plasma reactor, and a carbon monoxide discharge line for discharging carbon monoxide from the plasma reactor, wherein the plasma reactor comprises a casing, and a plurality of electrode panels and carbon dioxide adsorption members disposed within the casing, the carbon monoxide production system.

[0008] In the carbon monoxide production system described above, carbon dioxide is first adsorbed onto a carbon dioxide adsorption material in the plasma reactor. Then, the sufficiently adsorbed carbon dioxide is converted into carbon monoxide. Therefore, according to the carbon monoxide production system described above, carbon dioxide can be converted into carbon monoxide with excellent efficiency through plasma processing. As a result, carbon monoxide can be produced more efficiently according to the carbon monoxide production system described above.

[0009] The present invention [2] includes the carbon monoxide production system described in [1] above, wherein the carbon monoxide production system comprises a control unit, the control unit controls the power frequency of the plasma reactor to 20 kHz or less.

[0010] In the carbon monoxide production system described above, the power frequency of the plasma reactor is relatively low. When the power frequency is relatively low, the current value per pulse is larger, even if the magnitude of the applied power is the same, compared to when the power frequency is relatively high. Therefore, carbon monoxide can be produced more efficiently with such a carbon monoxide production system.

[0011] The present invention [3] includes the carbon monoxide production system according to [1] or [2] above, wherein the carbon monoxide production system comprises a control unit, the control unit stops the plasma reactor according to the carbon monoxide production efficiency.

[0012] In the carbon monoxide production system described above, the shutdown of the plasma reactor is adjusted according to the carbon monoxide production efficiency. Therefore, carbon monoxide can be produced more efficiently using this system.

[0013] The present invention [4] provides a carbon monoxide production system comprising a control unit, the plasma reactor comprising a first plasma reactor and a second plasma reactor, the first plasma reactor comprising a first casing and a plurality of first electrode panels and a first carbon dioxide adsorption member disposed within the first casing, the second plasma reactor comprising a second casing and a plurality of second electrode panels and a second carbon dioxide adsorption member disposed within the second casing, the control unit selectively controls a first mode or a second mode, the first mode is used to produce carbon dioxide, the first plasma reactor The second mode includes a carbon monoxide production system according to any one of the above [1] to [3], wherein carbon dioxide is supplied to a plasma reactor to adsorb carbon dioxide onto the first carbon dioxide adsorption member, and the carbon dioxide adsorbed on the second carbon dioxide adsorption member is converted into carbon monoxide in the second plasma reactor, and the carbon dioxide adsorbed on the first carbon dioxide adsorption member is converted into carbon monoxide in the first plasma reactor.

[0014] Such a carbon monoxide production system selectively controls either a first mode or a second mode. As a result, when the first carbon dioxide adsorption member of the first plasma reactor adsorbs carbon dioxide, the second plasma reactor converts the carbon dioxide into carbon monoxide. Similarly, when the second carbon dioxide adsorption member of the second plasma reactor adsorbs carbon dioxide, the first plasma reactor converts the carbon dioxide into carbon monoxide. Therefore, according to the above carbon monoxide production system 1, continuously supplied carbon dioxide can be converted into carbon monoxide. Consequently, according to the above carbon monoxide production system 1, carbon monoxide can be continuously produced with excellent efficiency. Effects of the Invention

[0015] According to the carbon monoxide production system of the present invention, carbon monoxide can be produced more efficiently. Brief Description of the Drawings

[0016] [Figure 1] Figure 1 is a schematic diagram showing the first embodiment (reference embodiment) of the carbon monoxide production system of the present invention. [Figure 2] Figure 2 is a graph showing the change in carbon monoxide production efficiency over time. [Figure 3] Figure 3 is a schematic diagram showing the second embodiment of the carbon monoxide production system of the present invention. [Figure 4] Figure 4 is a graph showing the relationship between the production amount of carbon monoxide and time in Reference Examples 1 to 4. Modes for Carrying Out the Invention

[0017] 1. First Embodiment (1) Overall Configuration The carbon monoxide production system converts carbon dioxide into carbon monoxide. More specifically, the carbon monoxide production system allows a gas containing carbon dioxide (untreated gas) to pass in a predetermined direction, subjects the carbon dioxide to plasma treatment, and produces a gas containing carbon monoxide (treated gas). In the following description, the flow direction of the untreated gas and the treated gas is referred to as the gas flow direction.

[0018] The first embodiment of the carbon monoxide production system will be described in detail with reference to Figure 1.

[0019] In Figure 1, the carbon monoxide production system 1 includes a plasma reactor 3, a carbon dioxide supply line 4, a carbon monoxide discharge line 5, a power supply unit 8, and a control unit 9.

[0020] Plasma reactor 3 is a device that generates plasma. The plasma reactor 3 includes a casing 30, and a plurality of electrode panels 31 and a carbon dioxide adsorption member 35 that are arranged inside the casing 30.

[0021] The casing 30 has a hollow cylindrical shape. The casing 30 is arranged such that its longitudinal direction extends along the gas flow direction. A gas supply port is formed on the side wall of the casing 30 on the upstream side in the gas flow direction (the right side of the drawing sheet). The gas supply port is connected to a carbon dioxide supply line 4. A gas discharge port is formed on the side wall of the casing 30 on the downstream side in the gas flow direction (the left side of the drawing sheet). The gas discharge port is connected to a carbon monoxide discharge line 5.

[0022] The plurality of electrode panels 31 are arranged inside the casing 30 along the longitudinal direction (gas flow direction) of the casing 30. Further, the plurality of electrode panels 31 are arranged at intervals from each other along the direction perpendicular to the longitudinal direction (gas flow direction) of the casing 30. The number of the electrode panels 31 is not particularly limited. In FIG. 1, three electrode panels 31 are arranged inside the casing 30.

[0023] Each electrode panel 31 has a thin plate shape. The electrode panel 31 includes a conductor 33 and a dielectric 34, as shown in the enlarged view of FIG. 1.

[0024] The conductor 33 contains a metal material, and is preferably made of a metal material. Examples of the metal material include tungsten. The shape of the conductor 33 is not particularly limited. For example, the conductor 33 has a thin plate shape. The size of the conductor 33 is not particularly limited, and is appropriately set according to the purpose and application. The conductor 33 is electrically connected to a power supply unit 8 (described later) (refer to the broken line in FIG. 1). As a result, power is supplied to the conductor 33 from the power supply unit 8 (described later).

[0025] The dielectric 34 covers the conductor 33. For example, when the conductor 33 has a thin plate shape, the dielectric 34 covers both the front surface and the back surface of the conductor 33.

[0026] The dielectric 34 includes, for example, a dielectric material, and preferably consists of a dielectric material. Alumina is an example of a dielectric material. The size of the dielectric 34 is not particularly limited and can be set as appropriate depending on the purpose and application.

[0027] The carbon dioxide adsorption member 35 covers the surface of the electrode panel 31. More specifically, the carbon dioxide adsorption member 35 is laminated on the dielectric 34 on both the front and back surfaces of the electrode panel 31.

[0028] The carbon dioxide adsorption member 35 includes, for example, a carbon dioxide adsorption material, and preferably consists of a carbon dioxide adsorption material. Examples of carbon dioxide adsorption materials include alumina, zeolite, Ba / CeO2, Ca / CeO2, or combinations thereof. From the viewpoint of availability, alumina, zeolite, or combinations thereof are preferred.

[0029] The carbon dioxide adsorption member 35 is formed, for example, by applying a slurry containing a carbon dioxide adsorption material to the dielectric 34, and then firing the slurry coating. This places the carbon dioxide adsorption member 35 inside the casing 30. The size (thickness) of the carbon dioxide adsorption member 35 is not particularly limited and can be set appropriately according to the purpose and application.

[0030] The plasma reactor 3 is further equipped with a carbon dioxide adsorption amount sensor 32, if necessary.

[0031] The carbon dioxide adsorption amount sensor 32 is, for example, placed inside the casing 30 and detects the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35.

[0032] The carbon dioxide adsorption sensor 32 is not particularly limited, and any known sensor can be used. The carbon dioxide adsorption amount sensor 32 is electrically connected to the control unit 9 (described later) (see dashed line in Figure 1). This allows the carbon dioxide adsorption amount sensor 32 to input the amount of carbon dioxide adsorbed as an electrical signal to the control unit 9 (described later).

[0033] The carbon dioxide supply line 4 is provided to supply carbon dioxide to the plasma reactor 3. The carbon dioxide supply line 4 includes, for example, a carbon dioxide supply pipe 40.

[0034] The carbon dioxide supply pipe 40 is a pipe for supplying carbon dioxide to the plasma reactor 3. The upstream end (right side of the page) of the carbon dioxide supply pipe 40 in the gas flow 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 40 in the gas flow direction is connected to the gas supply port on the upstream side (right side of the page) of the casing 30 in the gas flow direction.

[0035] 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.

[0036] The carbon dioxide supply line 4 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 40 in the flow direction.

[0037] The carbon monoxide emission line 5 is provided for the purpose of emitting carbon monoxide from the plasma reactor 3. The carbon monoxide emission line 5 includes, for example, a carbon monoxide emission pipe 50.

[0038] The carbon monoxide exhaust pipe 50 is a pipe for discharging carbon monoxide from the plasma reactor 3. The upstream side of the carbon monoxide exhaust pipe 50 in the gas flow direction (right side of the paper) is connected to the gas outlet on the downstream side of the casing 30 in the gas flow direction (left side of the paper). The downstream end of the carbon monoxide exhaust pipe 50 in the gas flow direction (left side of the paper) is connected to the carbon monoxide supply destination (not shown).

[0039] 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.

[0040] The carbon monoxide discharge line 5 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 monoxide discharge pipe 50 in the flow direction.

[0041] The power supply unit 8 is a unit that supplies (applies) power (voltage) to the plasma reactor 3. Examples of the power supply unit 8 include a DC power supply unit, an AC power supply unit, and a pulse power supply unit. The power supply unit 8 is preferably a pulse power supply unit.

[0042] The power supply unit 8 is electrically connected to the electrode panel 31 of the plasma reactor 3 (see dashed line in Figure 1). This allows the power supply unit 8 to supply power to the plasma reactor 3 and generate plasma between the electrode panels 31.

[0043] Furthermore, the power supply unit 8 is electrically connected to the control unit 9 (see dashed line in Figure 1). As a result, the operation and shutdown of the power supply unit 8 are electrically controlled by the control unit 9.

[0044] The control unit 9 is a unit that electrically controls the power supply unit 8. The control unit 9 is, for example, a microcomputer. The control unit 9 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 8 based on various programs. In this way, the control unit 9 controls the plasma reactor 3.

[0045] Furthermore, the control unit 9 is electrically connected to the carbon dioxide adsorption amount sensor 32 (see dashed line in Figure 1). This allows the control unit 9 to control the plasma reactor 3 according to the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35.

[0046] (2) Operation of the plasma reactor In the carbon monoxide production system 1 described above, carbon dioxide is first supplied to the plasma reactor 3. More specifically, 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 3 via the carbon dioxide supply line 4.

[0047] 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.

[0048] The supply flow rate of the untreated gas is set according to the size and performance of the plasma reactor 3. 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.

[0049] Carbon dioxide in the untreated gas is adsorbed onto the carbon dioxide adsorption member 35 within the plasma reactor 3. The carbon dioxide adsorbed onto the carbon dioxide adsorption member 35 is then plasma-treated in the carbon monoxide production system 1.

[0050] More specifically, in this method, the power supply unit 8 is activated by the control unit 9, and power is supplied to the plasma reactor 3. This generates plasma between the electrode panels 31. Then, the carbon dioxide adsorbed on the carbon dioxide adsorption member 35 is decomposed by the plasma, producing carbon monoxide.

[0051] Carbon monoxide is discharged from the plasma reactor 3 via the carbon monoxide discharge line 5. More specifically, the gas to be treated, which includes carbon monoxide and a carrier (such as air), is discharged from the plasma reactor 3. After being discharged from the plasma reactor 3, the gas to be treated is supplied to a carbon monoxide supply destination (not shown) via the carbon monoxide discharge line 5.

[0052] 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.

[0053] As described above, the carbon monoxide production system 1 can efficiently convert carbon dioxide into carbon monoxide by adsorbing it onto the carbon dioxide adsorption member 35.

[0054] In other words, in the carbon monoxide production system 1 described above, carbon dioxide is first adsorbed onto the carbon dioxide adsorption member 35 in the plasma reactor 3. Then, the sufficiently adsorbed carbon dioxide is converted into carbon monoxide. Therefore, according to the carbon monoxide production system 1 described above, carbon dioxide can be converted into carbon monoxide with excellent efficiency by plasma processing. As a result, carbon monoxide can be produced more efficiently according to the carbon monoxide production system 1 described above.

[0055] (3) Applied power and power frequency In the carbon monoxide production system 1 described above, the amount of power supplied to the plasma reactor 3 (applied power) is controlled by the control unit 9. The amount of power supplied to the plasma reactor 3 (applied power) is not particularly limited as long as it is possible to generate plasma between the electrode panels 31, and is set according to the purpose and application.

[0056] More specifically, the power applied to the plasma reactor 3 is, for example, 10W or more, preferably 20W or more. Alternatively, the power applied to the plasma reactor 3 may be, for example, 200W or less, preferably 100W or less.

[0057] Furthermore, in the carbon monoxide production system 1 described above, the frequency (power frequency) of the power supplied to the plasma reactor 3 is controlled by the control unit 9.

[0058] More specifically, the power frequency of the plasma reactor 3 is, for example, 0.01 kHz or higher, preferably 0.1 kHz or higher, and more preferably 1 kHz or higher. Alternatively, the power frequency of the plasma reactor 3 is, for example, 100 kHz or lower, preferably 60 kHz or lower, and more preferably 40 kHz or lower.

[0059] From the viewpoint of carbon monoxide production efficiency, the power frequency of the plasma reactor 3 is preferably adjusted to a relatively low level. More preferably, the power frequency of the plasma reactor 3 is 20 kHz or less, even more preferably 10 kHz or less, and particularly preferably 5 kHz or less.

[0060] In the carbon monoxide production system 1 described above, the power frequency of the plasma reactor 3 is relatively low. When the power frequency is relatively low, the current value per pulse is larger, even if the magnitude of the applied power is the same, compared to when the power frequency is relatively high. Therefore, carbon monoxide can be produced more efficiently with this carbon monoxide production system 1.

[0061] (4) Timing of operation and shutdown In the carbon monoxide production system 1 described above, the timing of operation and shutdown of the plasma reactor 3 is set appropriately according to the purpose and application.

[0062] For example, the plasma reactor 3 may be kept running continuously while the carbon monoxide production system 1 is in operation. Alternatively, for example, the plasma reactor 3 may be operated at appropriate intervals while the carbon monoxide production system 1 is in operation, and the plasma reactor 3 may be stopped at appropriate intervals.

[0063] From the viewpoint of carbon monoxide production efficiency, it is preferable to operate the plasma reactor 3 at appropriate timings while the carbon monoxide production system 1 is in operation, and to stop the plasma reactor 3 at appropriate timings.

[0064] The timing for activating and stopping the plasma reactor 3 is not particularly limited. For example, the plasma reactor 3 may be activated and stopped at predetermined time intervals set in advance.

[0065] Furthermore, for example, the plasma reactor 3 may be operated according to the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35.

[0066] More specifically, in this method, a threshold for the amount of carbon dioxide adsorbed in order to activate the plasma reactor 3 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 3.

[0067] 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 35.

[0068] In this method, the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35 is detected by the carbon dioxide adsorption amount sensor 32. The amount of carbon dioxide adsorbed is also input as an electrical signal to the control unit 9.

[0069] The control unit 9 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 3 is stopped. On the other hand, when the amount of carbon dioxide adsorbed is above the predetermined threshold, the power supply unit 8 is activated by the control unit 9, and power is supplied to the plasma reactor 3. Operating the plasma reactor 3 in this way allows for more efficient production of carbon monoxide.

[0070] In such cases, the plasma reactor 3 may be stopped depending on the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35.

[0071] In other words, if the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35 is less than a predetermined threshold, the power supply to the plasma reactor 3 may be stopped.

[0072] Alternatively, for example, the carbon monoxide generation efficiency in the plasma reactor 3 may be measured, and the plasma reactor 3 may be stopped according to that carbon monoxide generation efficiency.

[0073] The carbon monoxide production efficiency is the ratio of the power used to produce carbon monoxide to the total power applied to the plasma reactor 3 (applied power). More specifically, the carbon monoxide production efficiency is calculated according to the following formula.

[0074] Carbon monoxide generation efficiency (%) = Amount of carbon monoxide produced (mol) × Enthalpy of carbon monoxide generation (279.8 kJ / mol) / Power applied to the plasma reactor (kJ)

[0075] In the above formula, the amount of carbon monoxide produced (mol) is the amount of carbon monoxide emitted from the plasma reactor 3. Normally, the amount of carbon monoxide produced (mol) increases over time when the plasma reactor 3 is in operation. Also, as carbon monoxide is produced, the amount of carbon dioxide adsorbed decreases. Therefore, if the plasma reactor 3 is kept in operation, the amount of carbon monoxide produced (mol) will increase over time and then decrease.

[0076] The amount of carbon monoxide produced (mol) is measured by a known method. For example, a known carbon monoxide sensor is placed in the carbon monoxide exhaust pipe 50. The carbon monoxide sensor detects the amount of carbon monoxide in the carbon monoxide exhaust pipe 50 as the amount of carbon monoxide produced (mol). The amount of carbon monoxide produced (mol) is input as an electrical signal to the control unit 9.

[0077] In the above equation, the enthalpy of carbon monoxide production (279.8 kJ / mol) is a fixed coefficient.

[0078] In the above formula, the power applied to the plasma reactor (kJ) is the integrated (total) amount of power supplied to the plasma reactor 3 from the time the plasma reactor 3 starts operating until the time the amount of carbon monoxide produced (mol) is measured. In other words, the power applied to the plasma reactor (integrated value) increases over time.

[0079] The power applied to the plasma reactor (kJ) is measured as the plasma reactor 3 operates. Furthermore, the power applied to the plasma reactor (kJ) is reset when the plasma reactor 3 stops. In other words, the power applied to the plasma reactor (kJ) is the integrated (total) amount of power supplied to the plasma reactor 3 during one operation cycle.

[0080] The control unit 9 then calculates the carbon monoxide generation efficiency according to the above formula, based on the amount of carbon monoxide produced (mol), the enthalpy of carbon monoxide production (279.8 kJ / mol), and the integrated value (kJ) of the power applied to the plasma reactor 3.

[0081] The carbon monoxide generation efficiency typically increases over time when the plasma reactor 3 is in operation, as shown in Figure 2. On the other hand, if the plasma reactor 3 is kept running, the applied power (integrated value) to the plasma reactor 3 increases over time. Also, the amount of carbon monoxide generated decreases. Therefore, the carbon monoxide generation efficiency increases over time and then decreases.

[0082] Therefore, preferably, the timing of stopping the plasma reactor 3 is controlled according to the carbon monoxide generation efficiency.

[0083] More specifically, an increase in carbon monoxide production efficiency is detected by control unit 9. Subsequently, a decrease in carbon monoxide production efficiency is detected by control unit 9. As a result, the peak of carbon monoxide production efficiency (arrow A in Figure 2) is detected by control unit 9.

[0084] Then, when the carbon monoxide generation efficiency reaches its peak (arrow A in Figure 2), the power supply to the plasma reactor 3 is stopped by the control unit 9. In other words, the control unit 9 stops the power supply to the plasma reactor 3 when the carbon monoxide generation efficiency begins to decrease.

[0085] In the carbon monoxide production system 1 described above, the stopping of the plasma reactor 3 is adjusted according to the carbon monoxide production efficiency. Therefore, carbon monoxide can be produced more efficiently according to the carbon monoxide production system 1 described above.

[0086] Furthermore, the power supply to the plasma reactor 3 is stopped and then restarted in the same manner as described above. More specifically, the power supply to the plasma reactor 3 is started when the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35 exceeds a predetermined threshold. This operation is repeated by the control unit 9. As a result, carbon dioxide is intermittently converted into carbon monoxide by the carbon monoxide production system 1 described above.

[0087] According to this carbon monoxide production system 1, carbon monoxide can be produced more efficiently.

[0088] 2. Second Embodiment The carbon monoxide production system 1 described above may be equipped with two or more plasma reactors 3. Furthermore, the carbon monoxide production system 1 may selectively use any of the two or more plasma reactors 3.

[0089] (1) Overall structure The second embodiment of the carbon monoxide production system will be described in detail below with reference to Figure 3.

[0090] In Figure 3, the carbon monoxide production system 1 comprises a plasma reactor 3, a carbon dioxide supply line 4, a carbon monoxide emission line 5, the power supply unit 8, and the control unit 9.

[0091] The plasma reactor 3 comprises a first plasma reactor 3A and a second plasma reactor 3B.

[0092] The first plasma reactor 3A and the second plasma reactor 3B each have the same configuration as the plasma reactor 3 shown in Figure 1.

[0093] Specifically, as shown in Figure 1, the first plasma reactor 3A comprises a casing 30 (hereinafter referred to as the first casing 30A), a plurality of electrode panels 31 (hereinafter referred to as the first electrode panel 31A), and a carbon dioxide adsorption member 35 (hereinafter referred to as the first carbon dioxide adsorption member 35A). The first electrode panel 31A comprises a conductor 33 (hereinafter referred to as the first conductor 33A) and a dielectric 34 (hereinafter referred to as the first dielectric 34A), as shown in the enlarged view of Figure 1. Furthermore, the first plasma reactor 3A also comprises a carbon dioxide adsorption amount sensor 32 (hereinafter referred to as the first carbon dioxide adsorption amount sensor 32A).

[0094] The second plasma reactor 3B also comprises a casing 30 (hereinafter referred to as the second casing 30B), a plurality of electrode panels 31 (hereinafter referred to as the second electrode panel 31B), and a carbon dioxide adsorption member 35 (hereinafter referred to as the second carbon dioxide adsorption member 35B), as shown in Figure 1. The second electrode panel 31B comprises a conductor 33 (hereinafter referred to as the second conductor 33B) and a dielectric 34 (hereinafter referred to as the second dielectric 34B), as shown in the enlarged view of Figure 1. The second plasma reactor 3B also further comprises a carbon dioxide adsorption amount sensor 32 (hereinafter referred to as the second carbon dioxide adsorption amount sensor 32B).

[0095] In Figure 3, the carbon dioxide supply line 4 comprises a supply-side main pipe 45, a supply-side first pipe 41, a supply-side second pipe 42, and a supply-side three-way valve 43.

[0096] The supply-side main pipe 45 is a pipe for supplying carbon dioxide to the supply-side first pipe 41 or the supply-side second pipe 42. The upstream end (right side of the page) of the supply-side main pipe 45 in the direction of gas flow is connected to a carbon dioxide supply source (not shown). The downstream end (left side of the page) of the supply-side main pipe 45 in the direction of gas flow is connected to the supply-side three-way valve 43.

[0097] The supply-side first pipe 41 is a pipe for supplying carbon dioxide to the first plasma reactor 3A. The upstream end (right side of the page) of the supply-side first pipe 41 in the gas flow direction is connected to the supply-side three-way valve 43. The downstream end (left side of the page) of the supply-side first pipe 41 in the gas flow direction is connected to the first plasma reactor 3A.

[0098] The supply-side second pipe 42 is a pipe for supplying carbon dioxide to the first plasma reactor 3B. The upstream end (right side of the page) of the supply-side second pipe 42 in the gas flow direction is connected to the supply-side three-way valve 43. The downstream end (left side of the page) of the supply-side second pipe 42 in the gas flow direction is connected to the second plasma reactor 3B.

[0099] The supply-side three-way valve 43 connects the downstream end of the supply-side main pipe 45 in the direction of gas flow, the upstream end of the supply-side first pipe 41 in the direction of gas flow, and the upstream end of the supply-side second pipe 42 in the direction of gas flow.

[0100] Furthermore, the supply-side three-way valve 43 is electrically connected to the control unit 9 (described later). As a result, the opening and closing of the supply-side three-way valve 43 is controlled by the control unit 9 (described later).

[0101] In Figure 3, the carbon monoxide emission line 5 comprises an emission-side first pipe 51, an emission-side second pipe 52, and an emission-side main pipe 55.

[0102] The first discharge pipe 51 is a pipe for discharging carbon monoxide from the first plasma reactor 3A. The upstream end (right side of the page) of the first discharge pipe 51 in the gas flow direction is connected to the first plasma reactor 3A. The downstream end (left side of the page) of the first discharge pipe 51 in the gas flow direction is connected to the main discharge pipe 55.

[0103] The second discharge pipe 52 is a pipe for discharging carbon monoxide from the second plasma reactor 3B. The upstream end (right side of the page) of the second discharge pipe 52 in the gas flow direction is connected to the second plasma reactor 3. The downstream end (left side of the page) of the second discharge pipe 52 in the gas flow direction is connected to the main discharge pipe 55.

[0104] The main discharge pipe 55 is a pipe for discharging carbon monoxide from the first discharge pipe 51 and the second discharge pipe 52. The upstream end of the main discharge pipe 55 in the direction of gas flow (right side of the page) is connected to the first discharge pipe 51 and the second discharge pipe 52, and they are combined. The downstream end of the main discharge pipe 55 in the direction of gas flow (left side of the page) is connected to the carbon monoxide supply destination (not shown).

[0105] (2) Operation of the plasma reactor In the carbon monoxide production system 1 described above, the opening and closing of the supply-side three-way valve 43 is controlled by the control unit 9, and carbon dioxide is selectively supplied to either the first plasma reactor 3A or the second plasma reactor 3B.

[0106] For example, first, the supply-side three-way valve 43 is controlled by the control unit 9, and the supply-side main pipe 45 and the supply-side first pipe 41 are connected. Also, the supply-side second pipe 42 is closed by the supply-side three-way valve 43.

[0107] As a result, carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) to the first casing 30A of the first plasma reactor 3A via the supply main pipe 45 and the supply first pipe 41. Inside the first casing 30A, the carbon dioxide is adsorbed by the first carbon dioxide adsorption member 35A.

[0108] In the carbon monoxide production system 1 described above, the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is detected by the first carbon dioxide adsorption amount sensor 32A and input as an electrical signal to the control unit 9.

[0109] The control unit 9 determines whether the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is above a predetermined threshold.

[0110] When the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is below a predetermined threshold, the above state is maintained by the control unit 9. That is, carbon dioxide is supplied to the first plasma reactor 3A and adsorbed by the first carbon dioxide adsorption member 35A. At this time, as will be described later, power is supplied to the second plasma reactor 3B (first mode).

[0111] On the other hand, if the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A exceeds a predetermined threshold, the supply-side three-way valve 43 is switched by the control unit 9. At the same time, power is supplied to the first plasma reactor 3A, and the power supply to the second plasma reactor 3B is stopped.

[0112] More specifically, if the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A exceeds a predetermined threshold, the control unit 9 changes the opening and closing of the supply-side three-way valve 43, and the supply-side first pipe 41 is closed by the supply-side three-way valve 43.

[0113] As a result, the supply of carbon dioxide to the first plasma reactor 3A is stopped. With the supply of carbon dioxide stopped, power is supplied to the first plasma reactor 3A, and plasma is generated between the first electrode panels 31A of the first plasma reactor 3A. The carbon dioxide adsorbed on the first carbon dioxide adsorption member 35A is then decomposed by the plasma, and carbon monoxide is produced.

[0114] Carbon monoxide is discharged from the first plasma reactor 3A. More specifically, the gas to be treated, which includes carbon monoxide and a carrier (such as air), is discharged from the first plasma reactor 3A. After being discharged from the first plasma reactor 3A, the gas to be treated is supplied to a carbon monoxide supply destination (not shown) via the discharge-side first pipe 51 and the discharge-side main pipe 55.

[0115] In addition, the opening and closing of the supply-side three-way valve 43 is changed by the control unit 9, and the supply-side main pipe 45 and the supply-side second pipe 42 are connected.

[0116] As a result, carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) to the second casing 30B of the second plasma reactor 3B via the supply main pipe 45 and the supply second pipe 42. The carbon dioxide is then adsorbed by the second carbon dioxide adsorption member 35B within the second casing 30B.

[0117] In other words, the control unit 9 supplies carbon dioxide to the second plasma reactor 3B, causing the carbon dioxide to be adsorbed onto the second carbon dioxide adsorption member 35, and the first plasma reactor 3A converts the carbon dioxide adsorbed onto the first carbon dioxide adsorption member 35 into carbon monoxide (second mode).

[0118] The amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B is detected by the second carbon dioxide adsorption amount sensor 32B and input as an electrical signal to the control unit 9.

[0119] The control unit 9 determines whether the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B is above a predetermined threshold.

[0120] When the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B is below a predetermined threshold, the control unit 9 maintains the above state. That is, carbon dioxide is supplied to the second plasma reactor 3B and adsorbed by the second carbon dioxide adsorption member 35B. At this time, as described above, power is supplied to the first plasma reactor 3A (second mode).

[0121] On the other hand, if the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B exceeds a predetermined threshold, the supply-side three-way valve 43 is switched by the control unit 9. At the same time, power is supplied to the second plasma reactor 3B, and the power supply to the first plasma reactor 3A is stopped.

[0122] More specifically, if the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B exceeds a predetermined threshold, the control unit 9 changes the opening and closing of the supply-side three-way valve 43, and the supply-side second pipe 42 is closed by the supply-side three-way valve 43.

[0123] This stops the supply of carbon dioxide to the second plasma reactor 3B. Then, with the supply of carbon dioxide stopped, power is supplied to the second plasma reactor 3B. As a result, plasma is generated between the second electrode panels 31B of the second plasma reactor 3B. The carbon dioxide adsorbed on the second carbon dioxide adsorption member 35B is then decomposed by the plasma, generating carbon monoxide.

[0124] Carbon monoxide is discharged from the second plasma reactor 3B. More specifically, the gas to be treated, which includes carbon monoxide and a carrier (such as air), is discharged from the second plasma reactor 3B. After being discharged from the second plasma reactor 3B, the gas to be treated is supplied to a carbon monoxide supply destination (not shown) via the discharge-side second pipe 52 and the discharge-side main pipe 55.

[0125] In addition, the opening and closing of the supply-side three-way valve 43 is changed by the control unit 9. The supply side main pipe 45 and the supply side first pipe 41 are connected.

[0126] As a result, carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) to the first casing 30A of the first plasma reactor 3A via the supply main pipe 45 and the supply first pipe 41. The carbon dioxide is then adsorbed by the first carbon dioxide adsorption member 35A within the first casing 30A.

[0127] In other words, the control unit 9 supplies carbon dioxide to the first plasma reactor 3A, causing the carbon dioxide to be adsorbed onto the first carbon dioxide adsorption member 35, and the second plasma reactor 3B converts the carbon dioxide adsorbed onto the second carbon dioxide adsorption member 35 into carbon monoxide (first mode).

[0128] The amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is detected by the first carbon dioxide adsorption amount sensor 32A and input as an electrical signal to the control unit 9.

[0129] The control unit 9 determines whether the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is above a predetermined threshold. If the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is above the predetermined threshold, the second mode described above is performed.

[0130] In this manner, the switching between the first mode and the second mode is repeated while the carbon monoxide production system 1 is in operation.

[0131] In other words, in the carbon monoxide production system 1 described above, the control unit 9 selectively controls either the first mode or the second mode.

[0132] As a result, when the first carbon dioxide adsorption member 35 of the first plasma reactor 3A adsorbs carbon dioxide, the second plasma reactor 3B converts the carbon dioxide into carbon monoxide. Also, when the second carbon dioxide adsorption member 35 of the second plasma reactor 3B adsorbs carbon dioxide, the first plasma reactor 3A converts the carbon dioxide into carbon monoxide. Therefore, according to the carbon monoxide production system 1 described above, continuously supplied carbon dioxide can be converted into carbon monoxide. As a result, according to the carbon monoxide production system 1 described above, carbon monoxide can be continuously produced with excellent efficiency.

[0133] The number of plasma reactors 3 is not particularly limited; for example, there may be three or more.

[0134] Furthermore, in the second embodiment described above, the control unit 9 controls the first and second modes based on the amount of carbon dioxide adsorbed, but it is also possible to control the first and second modes based on a preset time interval, for example.

[0135] Furthermore, in the second embodiment described above, the control unit 9 selectively controls either the first mode or the second mode by switching the supply-side three-way valve 43. However, for example, the control unit 9 can also selectively control either the first mode or the second mode by using a known rotating member to swap the position of the first plasma reactor 3A and the position of the second plasma reactor 3B. [Examples]

[0136] 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.

[0137] Reference example 1 A mixed powder of zeolite and alumina (zeolite:alumina = 7:3 (mass ratio)) was prepared as a carbon dioxide adsorption material. A slurry of this mixed powder was applied to the surface of the electrode panel of the plasma reactor and fired at 500°C. This created a layer of carbon dioxide adsorption material on the electrode panel of the plasma reactor.

[0138] The electrode panel described above was set in the plasma reactor. A mixed gas of carbon dioxide and air (CO2 + carrier air) was then supplied to the plasma reactor casing at a rate of 1 L / min. This caused carbon dioxide to be adsorbed onto the carbon dioxide adsorption material. The CO2 concentration of the mixed gas was 600 ppm.

[0139] Furthermore, a high-voltage pulse power supply was connected to the plasma reactor, and a high-voltage pulse (power 30W, power frequency 5kHz) was applied to the electrode panel. This generated plasma between the electrode panels, converting carbon dioxide into carbon monoxide.

[0140] Then, at the outlet of the plasma reactor, the treated gas was collected, and the carbon monoxide content (ppm) was measured using a gas analyzer (NDIR; non-dispersive infrared absorption). This was defined as the amount of carbon monoxide produced. The relationship between the amount of carbon monoxide produced and time is shown in Figure 4.

[0141] Reference example2-4 The power of the high-voltage pulse was maintained at 30W. On the other hand, the power frequency was changed as follows. Otherwise, carbon dioxide was converted to carbon monoxide in the same manner as in Example 1.

[0142] Reference example In version 2, the power frequency was changed to 10 kHz. Also, Reference example In version 3, the power frequency was changed to 15kHz. Also, Reference example In version 4, the power frequency was changed to 20 kHz.

[0143] and, Reference example Using the same method as in 1, the amount of carbon monoxide produced at the outlet of the plasma reactor was measured. The relationship between the amount of carbon monoxide produced and time is shown in Figure 4. [Explanation of Symbols]

[0144] 1. Carbon monoxide production system 3 Plasma Reactor 4. Carbon dioxide supply lines 5. Carbon monoxide emission line 30 Casing 31 Electrode Panel 35 Carbon dioxide adsorption material

Claims

1. This is a carbon monoxide production system that converts carbon dioxide into carbon monoxide. Plasma reactor and A carbon dioxide supply line for supplying carbon dioxide to the plasma reactor, A carbon monoxide discharge line for discharging carbon monoxide from the plasma reactor, Control unit and Equipped with, The plasma reactor comprises a first plasma reactor and a second plasma reactor. The first plasma reactor is First casing and, A plurality of first electrode panels and a first carbon dioxide adsorption member are arranged within the first casing. Equipped with, The second plasma reactor is The second casing and A plurality of second electrode panels and a second carbon dioxide adsorption member are arranged within the second casing. Equipped with, The control unit selectively controls either the first mode or the second mode. The first mode involves supplying carbon dioxide to the first plasma reactor to adsorb carbon dioxide onto the first carbon dioxide adsorption member, and in the second plasma reactor, converting the carbon dioxide adsorbed onto the second carbon dioxide adsorption member into carbon monoxide. The second mode is a carbon monoxide production system that supplies carbon dioxide to the second plasma reactor to adsorb carbon dioxide onto the second carbon dioxide adsorption member, and converts the carbon dioxide adsorbed on the first carbon dioxide adsorption member into carbon monoxide in the first plasma reactor.

2. The carbon monoxide production system according to claim 1, wherein the control unit controls the power frequency of the plasma reactor to 20 kHz or less.

3. The carbon monoxide production system according to claim 1, wherein the control unit stops the plasma reactor according to the carbon monoxide production efficiency.

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