Carbon monoxide production system

Abstract

To provide a carbon monoxide production system which can produce carbon monoxide from carbon dioxide more efficiently.SOLUTION: A carbon monoxide production system 1 converts carbon dioxide into carbon monoxide. The carbon monoxide production system 1 includes: a plasma reactor 3; a carbon dioxide supply line 4 for supplying the carbon dioxide to the plasma reactor 3; and a carbon monoxide discharge line 5 for discharging the carbon monoxide from the plasma reactor 3. The plasma reactor 3 includes: a casing 30; and a plurality of electrode panels 31 and a carbon dioxide adsorption member 35 disposed in the casing 30. The carbon dioxide adsorption member contains at least one selected from the group consisting of CeO2, CeO2 having strontium supported thereon, and Al2O3 having an alkali metal supported thereon.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a carbon monoxide production system. [Background technology]

[0002] In recent years, from the viewpoint of carbon neutrality, conversion of carbon dioxide to carbon monoxide has been studied. Carbon dioxide is contained in, for example, exhaust gas from factories. Carbon monoxide is used, for example, as 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 plasma treating carbon dioxide is known. More specifically, the following carbon monoxide production method has been proposed. This carbon monoxide production method includes a step of generating plasma particles from a plasma particle-generating raw material gas, and a step of contacting the plasma particles with a carbon dioxide-containing raw material 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 Patent Application Laid-Open 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, it is required to efficiently convert carbon dioxide into carbon monoxide.

[0006] The present invention is a carbon monoxide production system that can more efficiently produce carbon monoxide from carbon dioxide. [Means for solving the problem]

[0007] The present invention [1] is a carbon monoxide production system that converts carbon dioxide into carbon monoxide, and includes 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, the plasma reactor including a casing and a plurality of electrode panels and a carbon dioxide adsorption member disposed within the casing, the carbon dioxide adsorption member containing at least one selected from the group consisting of CeO2, strontium-loaded CeO2, and alkali metal-loaded Al2O3.

[0008] In the carbon monoxide production system, carbon dioxide is first adsorbed onto the carbon dioxide adsorption member in the plasma reactor. The fully adsorbed carbon dioxide is then converted into carbon monoxide. Therefore, the carbon monoxide production system can convert carbon dioxide into carbon monoxide with excellent efficiency through plasma treatment. As a result, the carbon monoxide production system can produce carbon monoxide more efficiently.

[0009] In particular, in the carbon monoxide production system, the carbon dioxide adsorption member contains at least one selected from the group consisting of CeO, strontium-loaded CeO, and alkali metal-loaded AlO. Such a carbon dioxide adsorption member has particularly excellent carbon dioxide adsorption ability. As a result, the carbon monoxide production system can produce carbon monoxide particularly efficiently. [Effects of the Invention]

[0010] According to the carbon monoxide production system of the present invention, carbon monoxide can be produced more efficiently. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing a first embodiment of a carbon monoxide producing system according to the present invention. [Figure 2]FIG. 2 is a graph showing the carbon monoxide production efficiency versus time. [Figure 3] FIG. 3 is a schematic diagram showing a second embodiment of the carbon monoxide producing system of the present invention. [Figure 4] FIG. 4 is a graph showing the relationship between the carbon dioxide adsorption materials of Examples 1 to 4 and Comparative Examples 1 to 3 and the amount of carbon monoxide produced. DETAILED DESCRIPTION OF THE INVENTION

[0012] 1. First embodiment (1) Overall structure The carbon monoxide production system converts carbon dioxide into carbon monoxide. More specifically, the carbon monoxide production system passes a gas containing carbon dioxide (untreated gas) in a predetermined direction and plasma-treats the carbon dioxide to produce a gas containing carbon monoxide (treated gas). Note that, hereinafter, the flow directions of the untreated gas and the treated gas are referred to as the gas flow directions.

[0013] A first embodiment of a carbon monoxide producing system will be described in detail with reference to FIG.

[0014] In FIG. 1, a carbon monoxide producing 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 .

[0015] The 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 disposed within the casing 30.

[0016] The casing 30 has a hollow cylindrical shape. The casing 30 is arranged so that its longitudinal direction is along the gas flow direction. A gas supply port is formed in the side wall of the casing 30 on the upstream side in the gas flow direction (right side in the drawing). The gas supply port is connected to a carbon dioxide supply line 4. A gas exhaust port is formed in the side wall of the casing 30 on the downstream side in the gas flow direction (left side in the drawing). The gas exhaust port is connected to a carbon monoxide exhaust line 5.

[0017] The plurality of electrode panels 31 are arranged inside the casing 30 along the longitudinal direction (gas flow direction) of the casing 30. The plurality of electrode panels 31 are also arranged at intervals from one another along a direction perpendicular to the longitudinal direction (gas flow direction) of the casing 30. The number of electrode panels 31 is not particularly limited. In FIG. 1, three electrode panels 31 are arranged inside the casing 30.

[0018] Each electrode panel 31 has a thin plate shape and includes a conductor 33 and a dielectric 34, as shown in the enlarged view of FIG.

[0019] The conductor 33 includes a metal material, and is preferably made of a metal material. An example of the metal material is 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 set appropriately depending on the purpose and application. The conductor 33 is electrically connected to the power supply unit 8 (described later) (see the dashed line in FIG. 1). This allows the conductor 33 to receive power from the power supply unit 8 (described later).

[0020] The dielectric 34 covers the conductor 33. For example, if the conductor 33 has a thin plate shape, the dielectric 34 covers both the front and rear surfaces of the conductor 33.

[0021] The dielectric 34 includes, for example, a dielectric material, and is preferably made of, a dielectric material such as alumina. The size of the dielectric 34 is not particularly limited and may be set appropriately depending on the purpose and application.

[0022] The carbon dioxide adsorbing member 35 covers the surface of the electrode panel 31. More specifically, the carbon dioxide adsorbing member 35 is laminated on the dielectric 34 on both the front and rear surfaces of the electrode panel 31.

[0023] The carbon dioxide adsorbing member 35 contains at least one selected from the group consisting of CeO2 (that is, CeO2 not supporting a metal), CeO2 supporting strontium, and Al2O3 supporting an alkali metal.

[0024] More specifically, the carbon dioxide adsorption member 35 is a molded product obtained by molding a carbon dioxide adsorption material. The carbon dioxide adsorption material contains at least one selected from the group consisting of CeO2 with no metal supported thereon, CeO2 with strontium supported thereon (Sr / CeO2), and Al2O3 with an alkali metal supported thereon.

[0025] The method for obtaining metal-free CeO2 is not particularly limited, and known methods can be used. CeO2 can also be obtained as a commercially available product.

[0026] As a method for producing strontium-supported CeO2 (Sr / CeO2), for example, the following method can be mentioned.

[0027] For example, first, a metal salt containing strontium (e.g., nitrate) is dissolved in distilled water to obtain a solution containing strontium. Next, CeO2 is added to the solution containing strontium, and the mixture is heated while being mixed to evaporate and dry. The resulting dried product is then calcined. The calcination temperature is, for example, 400 to 800°C, preferably 500 to 700°C. The calcination time is, for example, 0.5 to 6 hours, preferably 1 to 4 hours. By the above method, strontium can be supported on CeO2. As a result, CeO2 supported with strontium (Sr / CeO2) is produced.

[0028] In the strontium-supported CeO2, the amount of strontium supported is appropriately set. For example, the ratio of strontium to the total moles of strontium (Sr) and CeO2 is, for example, 5 to 30 mol%, preferably 10 to 30 mol%, more preferably 10 to 25 mol%, and even more preferably 15 to 20 mol%. That is, the ratio of CeO2 to the total moles of strontium (Sr) and CeO2 is, for example, 70 to 95 mol%, preferably 70 to 90 mol%, more preferably 75 to 90 mol%, and even more preferably 80 to 85 mol%.

[0029] In the alkali metal-supported Al2O3, examples of Al2O3 include α-Al2O3, θ-Al2O3, and γ-Al2O3. These can be used alone or in combination of two or more. γ-Al2O3 is preferred as Al2O3.

[0030] The method for obtaining Al2O3 is not particularly limited, and known methods can be used. Al2O3 can also be obtained as a commercially available product.

[0031] In the case of Al2O3 carrying an alkali metal, examples of the alkali metal include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). These can be used alone or in combination of two or more. Preferred examples of the alkali metal include lithium (Li), sodium (Na), and potassium (K), more preferably sodium (Na) and potassium (K), and even more preferably sodium (Na).

[0032] More specifically, examples of alkali metal-supported Al2O3 include lithium-supported Al2O3 (Li / Al2O3), sodium-supported Al2O3 (Na / Al2O3), potassium-supported Al2O3K / Al2O3, rubidium-supported Al2O3 (Rb / Al2O3), and cesium-supported Al2O3 (Cs / Al2O3). These can be used alone or in combination of two or more. Examples of Al2O3 carrying an alkali metal include preferably lithium-loaded Al2O3 (Li / Al2O3), sodium-loaded Al2O3 (Na / Al2O3), and potassium-loaded Al2O3 (K / Al2O3), more preferably sodium-loaded Al2O3 (Na / Al2O3) and potassium-loaded Al2O3 (K / Al2O3), and even more preferably sodium-loaded Al2O3 (Na / Al2O3).

[0033] Examples of methods for producing Al2O3 carrying an alkali metal include the following methods.

[0034] For example, first, a metal salt (e.g., nitrate) containing an alkali metal is dissolved in distilled water to obtain a solution containing the alkali metal. Next, Al2O3 is added to the solution containing the alkali metal, and the mixture is heated while being mixed to evaporate and dry. The resulting dried product is then calcined. The calcination temperature is, for example, 400 to 800°C, preferably 500 to 700°C. The calcination time is, for example, 0.5 to 6 hours, preferably 1 to 4 hours. By the above method, the alkali metal can be supported on Al2O3. As a result, Al2O3 supported with the alkali metal is produced.

[0035] In the alkali metal-supported Al2O3, the amount of alkali metal supported is appropriately set. For example, the ratio of the alkali metal to the total moles of the alkali metal and Al2O3 is, for example, 5 to 30 mol%, preferably 10 to 30 mol%, more preferably 10 to 25 mol%, and even more preferably 15 to 20 mol%. That is, the ratio of Al2O3 to the total moles of the alkali metal and Al2O3 is, for example, 70 to 95 mol%, preferably 70 to 90 mol%, more preferably 75 to 90 mol%, and even more preferably 80 to 85 mol%.

[0036] The carbon dioxide adsorbing material can contain carbon dioxide adsorbing materials other than CeO2, CeO2 supporting strontium (Sr / CeO2), and Al2O3 supporting an alkali metal (hereinafter, other carbon dioxide adsorbing materials).

[0037] Other carbon dioxide adsorption materials include, for example, zeolite, barium-loaded CeO2 (Ba / CeO2), and calcium-loaded CeO2 (Ca / CeO2). These can be used alone or in combination of two or more. The content of the other carbon dioxide adsorption materials is appropriately set within a range that does not impair the excellent effects of the present invention.

[0038] Preferably, the carbon dioxide adsorption material does not contain any other carbon dioxide adsorption material. That is, the carbon dioxide adsorption material preferably comprises at least one selected from the group consisting of CeO2, strontium-supported CeO2 (Sr / CeO2), and alkali metal-supported Al2O3. The carbon dioxide adsorption material more preferably comprises alkali metal-supported Al2O3. The carbon dioxide adsorption material further preferably comprises sodium-supported Al2O3.

[0039] There are no particular limitations on the method for manufacturing the carbon dioxide adsorption member 35. For example, a slurry containing a carbon dioxide adsorption material is applied to the dielectric 34, and the resulting coating is fired. As a result, the carbon dioxide adsorption member 35 made of the carbon dioxide adsorption material is formed on the surface of the dielectric 34 as a fired body of the coating. As a result, the carbon dioxide adsorption member 35 is disposed inside the casing 30. There are no particular limitations on the size (thickness) of the carbon dioxide adsorption member 35, and it may be set appropriately depending on the purpose and application.

[0040] The plasma reactor 3 further includes a carbon dioxide adsorption amount sensor 32 as required.

[0041] The carbon dioxide adsorption amount sensor 32 is disposed, for example, inside the casing 30 and detects the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member .

[0042] There are no particular limitations on the carbon dioxide adsorption sensor 32, and a known sensor may be used. The carbon dioxide adsorption amount sensor 32 is electrically connected to a control unit 9 (described later) (see the dashed line in FIG. 1). This allows the carbon dioxide adsorption amount sensor 32 to input the amount of carbon dioxide adsorption to the control unit 9 (described later) as an electrical signal.

[0043] 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.

[0044] 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 drawing) 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 drawing) of the carbon dioxide supply pipe 40 in the gas flow direction is connected to a gas supply port on the upstream side (right side of the drawing) of the casing 30 in the gas flow direction.

[0045] The carbon dioxide supply source (not shown) is not particularly limited, and examples of the carbon dioxide supply source include various factory facilities and carbon dioxide storage tanks.

[0046] The carbon dioxide supply line 4 may be provided with an on-off valve (not shown) and / or a pump (not shown) as needed. The on-off valve (not shown) and / or the pump (not shown) are interposed, for example, in the middle of the carbon dioxide supply pipe 40 in the flow direction.

[0047] The carbon monoxide exhaust line 5 is provided to exhaust carbon monoxide from the plasma reactor 3. The carbon monoxide exhaust line 5 includes, for example, a carbon monoxide exhaust pipe 50.

[0048] The carbon monoxide exhaust pipe 50 is a pipe for exhausting carbon monoxide from the plasma reactor 3. The upstream side (right side of the drawing) of the carbon monoxide exhaust pipe 50 in the gas flow direction is connected to a gas exhaust port on the downstream side (left side of the drawing) of the casing 30 in the gas flow direction. The downstream end (left side of the drawing) of the carbon monoxide exhaust pipe 50 in the gas flow direction is connected to a carbon monoxide supply destination (not shown).

[0049] The destination of the carbon monoxide (not shown) is not particularly limited, and examples of the destination of the carbon monoxide include a resin production facility, a fuel production facility, and a carbon monoxide storage tank.

[0050] The carbon monoxide discharge line 5 may be provided with an on-off valve (not shown) and / or a pump (not shown) as necessary. The on-off valve (not shown) and / or the pump (not shown) are interposed, for example, in the middle of the carbon monoxide discharge pipe 50 in the flow direction.

[0051] 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.

[0052] The power supply unit 8 is electrically connected to the electrode panels 31 of the plasma reactor 3 (see dashed lines in FIG. 1). As a result, the power supply unit 8 supplies power to the plasma reactor 3 and generates plasma between the electrode panels 31.

[0053] Furthermore, the power supply unit 8 is electrically connected to the control unit 9 (see the broken line in FIG. 1). As a result, the activation and deactivation of the power supply unit 8 is electrically controlled by the control unit 9.

[0054] 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, a memory and a central processing unit (CPU). The memory includes a ROM and a RAM. The ROM stores various programs and fixed data. The RAM stores temporary input data. The central processing unit (CPU) activates and stops the power supply unit 8 based on the various programs. In this way, the control unit 9 controls the plasma reactor 3.

[0055] The control unit 9 is also electrically connected to the carbon dioxide adsorption amount sensor 32 (see the dashed line in FIG. 1). This allows the control unit 9 to control the plasma reactor 3 in accordance with the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35.

[0056] (2) Plasma reactor operation In the carbon monoxide producing system 1, first, carbon dioxide is supplied to the plasma reactor 3. 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 3 via a carbon dioxide supply line 4.

[0057] The carbon dioxide concentration in the untreated gas is, for example, 100 ppm or more, or preferably 300 ppm or more, and, for example, 10,000 ppm or less, or preferably 5,000 ppm or less.

[0058] 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 the carbon dioxide is, for example, 20 L / min, preferably 10 L / min.

[0059] The carbon dioxide in the untreated gas is adsorbed by the carbon dioxide adsorption member 35 in the plasma reactor 3. Then, the carbon dioxide adsorbed by the carbon dioxide adsorption member 35 is subjected to plasma treatment in the carbon monoxide production system 1.

[0060] More specifically, in this method, the power supply unit 8 is operated under the control of 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 to the carbon dioxide adsorption member 35 is decomposed by the plasma, producing carbon monoxide.

[0061] Carbon monoxide is discharged from the plasma reactor 3 via a carbon monoxide discharge line 5. More specifically, the gas to be treated containing 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.

[0062] The carbon monoxide concentration in the gas to be treated is, for example, 100 ppm or more, preferably 300 ppm or more, and for example, 10,000 ppm or less, preferably 5,000 ppm or less.

[0063] As described above, according to the carbon monoxide producing system 1, by having carbon dioxide adsorbed by the carbon dioxide adsorption member 35, carbon dioxide can be efficiently converted into carbon monoxide.

[0064] That is, in the carbon monoxide producing system 1, carbon dioxide is first adsorbed by the carbon dioxide adsorption member 35 in the plasma reactor 3. Then, the sufficiently adsorbed carbon dioxide is converted into carbon monoxide. Therefore, the carbon monoxide producing system 1 can convert carbon dioxide into carbon monoxide with excellent efficiency through plasma treatment. As a result, the carbon monoxide producing system 1 can produce carbon monoxide more efficiently.

[0065] In particular, in the carbon monoxide production system 1, the carbon dioxide adsorption member 35 contains at least one selected from the group consisting of CeO, strontium-supported CeO, and alkali metal-supported AlO. Such carbon dioxide adsorption member 35 has particularly excellent carbon dioxide adsorption ability. As a result, the carbon monoxide production system 1 can produce carbon monoxide particularly efficiently.

[0066] (3) Applied power and power frequency In the carbon monoxide production system 1, the magnitude of the power (applied power) supplied to the plasma reactor 3 is controlled by the control unit 9. The magnitude of the power (applied power) supplied to the plasma reactor 3 is not particularly limited as long as it can generate plasma between the electrode panels 31, and is set according to the purpose and application.

[0067] In the carbon monoxide producing system 1, the frequency of the power supplied to the plasma reactor 3 (power frequency) is controlled by the control unit 9. There are no particular limitations on the power frequency of the plasma reactor 3. Preferably, the power frequency of the plasma reactor 3 is set according to the type and amount of the carbon dioxide adsorption member.

[0068] (4) Timing of activation and deactivation In the carbon monoxide production system 1, the timing of activation and deactivation of the plasma reactor 3 is set appropriately depending on the purpose and application.

[0069] For example, the plasma reactor 3 may be operated continuously during operation of the carbon monoxide production system 1. Furthermore, for example, during operation of the carbon monoxide production system 1, the plasma reactor 3 may be operated at an appropriate timing, and the plasma reactor 3 may be stopped at an appropriate timing.

[0070] From the viewpoint of carbon monoxide production efficiency, it is preferable that the plasma reactor 3 be operated at an appropriate timing while the carbon monoxide production system 1 is in operation, and that the plasma reactor 3 be stopped at an appropriate timing.

[0071] There are no particular limitations on the timing at which the plasma reactor 3 is activated and stopped. For example, the plasma reactor 3 may be activated and stopped at predetermined time intervals.

[0072] Furthermore, for example, the plasma reactor 3 may be operated in accordance with the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member .

[0073] More specifically, in this method, a threshold value for the amount of carbon dioxide adsorption is set in advance for operating the plasma reactor 3. The threshold value for the amount of carbon dioxide adsorption is set appropriately depending on the size and performance of the plasma reactor 3.

[0074] The threshold value of the amount of carbon dioxide adsorption is, for example, a value of 50 to 100% of the maximum value (limit value) of the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35.

[0075] 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 adsorption is input to the control unit 9 as an electric signal.

[0076] The control unit 9 determines whether the amount of adsorbed carbon dioxide is equal to or greater than the predetermined threshold. Then, while the amount of adsorbed carbon dioxide is less than the predetermined threshold, the plasma reactor 3 is stopped. On the other hand, when the amount of adsorbed carbon dioxide is equal to or greater than the predetermined threshold, the power supply unit 8 is operated under the control of the control unit 9, and power is supplied to the plasma reactor 3. Operating the plasma reactor 3 in this manner allows for more efficient production of carbon monoxide.

[0077] In such a case, the plasma reactor 3 may be stopped depending on the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member .

[0078] That is, when the amount of carbon dioxide adsorbed by the carbon dioxide adsorption member 35 is less than a predetermined threshold value that has been set in advance, the supply of power to the plasma reactor 3 may be stopped.

[0079] Furthermore, for example, the carbon monoxide generation efficiency in the plasma reactor 3 may be measured, and the plasma reactor 3 may be stopped depending on the carbon monoxide generation efficiency.

[0080] The carbon monoxide generation efficiency is the ratio of the power used to produce carbon monoxide to the amount of power applied to the plasma reactor 3 (applied power amount). More specifically, the carbon monoxide generation efficiency is calculated according to the following formula.

[0081] Carbon monoxide production efficiency (%) = carbon monoxide production amount (mol) × carbon monoxide production enthalpy (279.8 kJ / mol) / applied power of plasma reactor (kJ)

[0082] In the above formula, the amount of carbon monoxide produced (mol) is the amount of carbon monoxide discharged from the plasma reactor 3. Normally, when the plasma reactor 3 is operated, the amount of carbon monoxide produced (mol) increases over time. Furthermore, as carbon monoxide is produced, the amount of carbon dioxide adsorbed decreases. Therefore, when the plasma reactor 3 is continuously operated, the amount of carbon monoxide produced (mol) increases over time and then decreases.

[0083] The amount of carbon monoxide produced (mol) is measured by a known method. For example, a known carbon monoxide sensor is disposed 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 to the control unit 9 as an electrical signal.

[0084] In the above equation, the enthalpy of formation of carbon monoxide (279.8 kJ / mol) is a fixed coefficient.

[0085] In the above formula, the applied power (kJ) of the plasma reactor 3 is the integrated value (total value) of the amount of power supplied to the plasma reactor 3 from the start of operation of the plasma reactor 3 until the time when the amount of carbon monoxide produced (mol) is measured. In other words, the applied power (integrated value) of the plasma reactor increases over time.

[0086] The applied power (kJ) of the plasma reactor 3 is measured while the plasma reactor 3 is operating. The applied power (kJ) of the plasma reactor 3 is reset when the plasma reactor 3 is stopped. In other words, the applied power (kJ) of the plasma reactor 3 is the integrated value (total value) of the amount of power supplied to the plasma reactor 3 during one operation of the plasma reactor 3.

[0087] Then, the control unit 9 calculates the carbon monoxide generation efficiency from the amount of carbon monoxide generated (mol), the enthalpy of carbon monoxide generation (279.8 kJ / mol), and the integrated value (kJ) of the power applied to the plasma reactor 3 according to the above formula.

[0088] As shown in Figure 2, the carbon monoxide generation efficiency usually increases over time when the plasma reactor 3 is operated. On the other hand, if the plasma reactor 3 is continuously operated, the applied power (integrated value) of 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.

[0089] Therefore, it is preferable that the timing of stopping the plasma reactor 3 is controlled in accordance with the carbon monoxide generation efficiency.

[0090] More specifically, an increase in carbon monoxide generation efficiency is confirmed by the control unit 9. Thereafter, a decrease in carbon monoxide generation efficiency is confirmed by the control unit 9. As a result, a peak in carbon monoxide generation efficiency (arrow A in FIG. 2) is confirmed by the control unit 9.

[0091] Then, when the carbon monoxide generation efficiency reaches its peak (arrow A in FIG. 2), the control unit 9 stops the supply of power to the plasma reactor 3. In other words, the control unit 9 stops the supply of power to the plasma reactor 3 when the carbon monoxide generation efficiency begins to decrease.

[0092] In the carbon monoxide producing system 1, the stop of the plasma reactor 3 is adjusted according to the carbon monoxide production efficiency. Therefore, the carbon monoxide producing system 1 can produce carbon monoxide more efficiently.

[0093] Furthermore, the supply of power to the plasma reactor 3 is stopped by the above-described method and then resumed by the above-described method. More specifically, when the amount of carbon dioxide adsorbed in the carbon dioxide adsorption member 35 is equal to or greater than a predetermined threshold, the supply of power to the plasma reactor 3 is started. Furthermore, such an operation is repeated by the control unit 9. As a result, carbon dioxide is intermittently converted into carbon monoxide by the carbon monoxide producing system 1.

[0094] According to such a carbon monoxide producing system 1, carbon monoxide can be produced more efficiently.

[0095] 2. Second embodiment The carbon monoxide producing system 1 can include two or more plasma reactors 3. Furthermore, the carbon monoxide producing system 1 can selectively use any one of the two or more plasma reactors 3.

[0096] (1) Overall structure Hereinafter, the second embodiment of the carbon monoxide producing system will be described in detail with reference to FIG.

[0097] In FIG. 3, the carbon monoxide producing system 1 includes a plasma reactor 3, a carbon dioxide supply line 4, a carbon monoxide discharge line 5, the power supply unit 8, and the control unit 9.

[0098] The plasma reactor 3 includes a first plasma reactor 3A and a second plasma reactor 3B.

[0099] The first plasma reactor 3A and the second plasma reactor 3B each have the same configuration as the plasma reactor 3 shown in FIG.

[0100] 1, the first plasma reactor 3A includes a casing 30 (hereinafter referred to as the first casing 30A), a plurality of electrode panels 31 (hereinafter referred to as the first electrode panels 31A), and a carbon dioxide adsorption member 35 (hereinafter referred to as the first carbon dioxide adsorption member 35A). As shown in the enlarged view of FIG. 1, the first electrode panel 31A includes a conductor 33 (hereinafter referred to as the first conductor 33A) and a dielectric 34 (hereinafter referred to as the first dielectric 34A). The first plasma reactor 3A further includes a carbon dioxide adsorption amount sensor 32 (hereinafter referred to as the first carbon dioxide adsorption amount sensor 32A).

[0101] 1, the second plasma reactor 3B also includes a casing 30 (hereinafter referred to as the second casing 30B), a plurality of electrode panels 31 (hereinafter referred to as the second electrode panels 31B), and a carbon dioxide adsorption member 35 (hereinafter referred to as the second carbon dioxide adsorption member 35B). As shown in the enlarged view of FIG. 1, the second electrode panel 31B includes a conductor 33 (hereinafter referred to as the second conductor 33B) and a dielectric 34 (hereinafter referred to as the second dielectric 34B). The second plasma reactor 3B also includes a carbon dioxide adsorption amount sensor 32 (hereinafter referred to as the second carbon dioxide adsorption amount sensor 32B).

[0102] In FIG. 3, the carbon dioxide supply line 4 includes 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.

[0103] The supply-side main pipe 45 is a pipe for supplying carbon dioxide to the first supply-side pipe 41 or the second supply-side pipe 42. The upstream end (right side of the drawing) of the supply-side main pipe 45 in the gas flow direction is connected to a carbon dioxide supply source (not shown). The downstream end (left side of the drawing) of the supply-side main pipe 45 in the gas flow direction is connected to the supply-side three-way valve 43.

[0104] 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 drawing) 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 drawing) of the supply-side first pipe 41 in the gas flow direction is connected to the first plasma reactor 3A.

[0105] The second supply-side pipe 42 is a pipe for supplying carbon dioxide to the first plasma reactor 3B. The upstream end (right side of the drawing) of the second supply-side pipe 42 in the gas flow direction is connected to the supply-side three-way valve 43. The downstream end (left side of the drawing) of the second supply-side pipe 42 in the gas flow direction is connected to the second plasma reactor 3B.

[0106] The supply side three-way valve 43 connects the downstream end of the supply side main pipe 45 in the gas flow direction, the upstream end of the supply side first pipe 41 in the gas flow direction, and the upstream end of the supply side second pipe 42 in the gas flow direction.

[0107] Furthermore, the supply-side three-way valve 43 is electrically connected to a 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).

[0108] In FIG. 3, the carbon monoxide discharge line 5 includes a first discharge pipe 51, a second discharge pipe 52, and a main discharge pipe 55.

[0109] The discharge-side first pipe 51 is a pipe for discharging carbon monoxide from the first plasma reactor 3A. The upstream end (right side of the drawing) of the discharge-side first pipe 51 in the gas flow direction is connected to the first plasma reactor 3A. The downstream end (left side of the drawing) of the discharge-side first pipe 51 in the gas flow direction is connected to the discharge-side main pipe 55.

[0110] The discharge-side second pipe 52 is a pipe for discharging carbon monoxide from the second plasma reactor 3B. The upstream end (right side of the drawing) of the discharge-side second pipe 52 in the gas flow direction is connected to the second plasma reactor 3. The downstream end (left side of the drawing) of the discharge-side second pipe 52 in the gas flow direction is connected to the discharge-side main pipe 55.

[0111] The discharge side main pipe 55 is a pipe for discharging carbon monoxide from the first discharge side pipe 51 and the second discharge side pipe 52. The upstream end (right side of the drawing) of the discharge side main pipe 55 in the gas flow direction is connected to the first discharge side pipe 51 and the second discharge side pipe 52 and joins them together. The downstream end (left side of the drawing) of the discharge side main pipe 55 in the gas flow direction is connected to a carbon monoxide supply destination (not shown).

[0112] (2) Plasma reactor operation In the carbon monoxide production system 1, 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.

[0113] 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 to each other. Also, the supply-side second pipe 42 is closed by the supply-side three-way valve 43.

[0114] As a result, carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) into the first casing 30A of the first plasma reactor 3A via the supply-side main pipe 45 and the first supply-side pipe 41. In the first casing 30A, the carbon dioxide is adsorbed by the first carbon dioxide adsorption member 35A.

[0115] In the carbon monoxide generating system 1, 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 is input to the control unit 9 as an electric signal.

[0116] The control unit 9 determines whether the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is equal to or greater than a predetermined threshold value.

[0117] When the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is less than a predetermined threshold, the above state is maintained under the control of 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).

[0118] On the other hand, when the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is equal to or greater than the predetermined threshold, the supply-side three-way valve 43 is switched under the control of the control unit 9. At the same time, power is supplied to the first plasma reactor 3A, and the supply of power to the second plasma reactor 3B is stopped.

[0119] More specifically, when the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is greater than or equal to a predetermined threshold, the opening and closing of the supply side three-way valve 43 is changed by the control unit 9, and the supply side first pipe 41 is blocked by the supply side three-way valve 43.

[0120] This stops the supply of carbon dioxide to the first plasma reactor 3A. Then, with the supply of carbon dioxide stopped, power is supplied to the first plasma reactor 3A, and plasma is generated between the first electrode panel 31A of the first plasma reactor 3A. Then, the carbon dioxide adsorbed to the first carbon dioxide adsorption member 35A is decomposed by the plasma, and carbon monoxide is produced.

[0121] Carbon monoxide is discharged from the first plasma reactor 3 A. More specifically, the gas to be treated containing carbon monoxide and a carrier (such as air) is discharged from the first plasma reactor 3 A. After being discharged from the first plasma reactor 3 A, 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.

[0122] At the same time, the control unit 9 changes the opening and closing state of the supply-side three-way valve 43, so that the supply-side main pipe 45 and the supply-side second pipe 42 communicate with each other.

[0123] As a result, carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) into the second casing 30B of the second plasma reactor 3B via the supply-side main pipe 45 and the second supply-side pipe 42. Then, the carbon dioxide is adsorbed by the second carbon dioxide adsorption member 35B in the second casing 30B.

[0124] That is, the control unit 9 supplies carbon dioxide to the second plasma reactor 3B, thereby causing the carbon dioxide to be adsorbed by the second carbon dioxide adsorption member 35, and also converts the carbon dioxide adsorbed by the first carbon dioxide adsorption member 35 into carbon monoxide in the first plasma reactor 3A (second mode).

[0125] 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 is input to the control unit 9 as an electrical signal.

[0126] The control unit 9 determines whether the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B is equal to or greater than a predetermined threshold value.

[0127] When the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B is less than a predetermined threshold, the above state is maintained under the control of the control unit 9. 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).

[0128] On the other hand, when the amount of carbon dioxide adsorbed by the second carbon dioxide adsorption member 35B is equal to or greater than the predetermined threshold, the supply-side three-way valve 43 is switched under the control of the control unit 9. At the same time, power is supplied to the second plasma reactor 3B, and the supply of power to the first plasma reactor 3A is stopped.

[0129] More specifically, when the amount of carbon dioxide adsorption by the second carbon dioxide adsorption member 35B is greater than or equal to a predetermined threshold, the opening and closing of the supply side three-way valve 43 is changed by the control unit 9, and the supply side second pipe 42 is blocked by the supply side three-way valve 43.

[0130] As a result, the supply of carbon dioxide to the second plasma reactor 3B is stopped. 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 panel 31B of the second plasma reactor 3B. Then, the carbon dioxide adsorbed to the second carbon dioxide adsorption member 35B is decomposed by the plasma, and carbon monoxide is produced.

[0131] Carbon monoxide is discharged from the second plasma reactor 3B. More specifically, the gas to be treated containing 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.

[0132] At the same time, the control unit 9 changes the opening and closing of the supply-side three-way valve 43. The supply-side main pipe 45 and the supply-side first pipe 41 are in communication with each other.

[0133] As a result, carbon dioxide is continuously supplied from a carbon dioxide supply source (not shown) into the first casing 30A of the first plasma reactor 3A via the supply-side main pipe 45 and the first supply-side pipe 41. Then, the carbon dioxide is adsorbed by the first carbon dioxide adsorption member 35A in the first casing 30A.

[0134] That is, the control unit 9 supplies carbon dioxide to the first plasma reactor 3A, thereby causing the carbon dioxide to be adsorbed by the first carbon dioxide adsorption member 35, and in the second plasma reactor 3B, converts the carbon dioxide adsorbed by the second carbon dioxide adsorption member 35 into carbon monoxide (first mode).

[0135] The amount of carbon dioxide adsorbed by first carbon dioxide adsorption member 35A is detected by first carbon dioxide adsorption amount sensor 32A, and is input to control unit 9 as an electrical signal.

[0136] The control unit 9 determines whether the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is equal to or greater than a predetermined threshold value. If the amount of carbon dioxide adsorbed by the first carbon dioxide adsorption member 35A is equal to or greater than the predetermined threshold value, the second mode is implemented.

[0137] In this manner, switching between the first mode and the second mode is repeated during operation of the carbon monoxide producing system 1.

[0138] In other words, in the carbon monoxide producing system 1, the control unit 9 selectively controls the first mode or the second mode.

[0139] 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, the carbon monoxide producing system 1 can convert continuously supplied carbon dioxide into carbon monoxide. As a result, the carbon monoxide producing system 1 can continuously produce carbon monoxide with excellent efficiency.

[0140] The number of plasma reactors 3 is not particularly limited, and may be, for example, three or more.

[0141] In addition, in the above second embodiment, the control unit 9 controls the first mode and the second mode based on the amount of carbon dioxide adsorption, but it can also control the first mode and the second mode based on, for example, a preset time interval.

[0142] In addition, in the above-described second embodiment, the control unit 9 selectively controls 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 use a known rotating member to interchange the positions of the first plasma reactor 3A and the second plasma reactor 3B, thereby selectively controlling the first mode or the second mode. [Example]

[0143] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Note that "parts" and "%" are by mass unless otherwise specified. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical property values, and parameters used in the following description can be substituted with the corresponding upper limit values ​​(numeric values ​​defined as "equal to or less than") or lower limit values ​​(numeric values ​​defined as "equal to or more than" or "exceeding") of the blending ratios (content ratios), physical property values, parameters, etc. described in the above "Form for Carrying Out the Invention."

[0144] 1. Preparation of Carbon Dioxide Adsorbent Material Preparation example 1 (CeO2) Commercially available CeO2 (model number JRC-CEO-6, manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) was prepared.

[0145] Preparation example 2 (Sr / CeO2) Strontium-loaded CeO2 (Sr / CeO2) was produced by the following method. Strontium nitrate was dissolved in distilled water to obtain a solution containing strontium. CeO2 was then added to the solution containing strontium, and the mixture was heated to 100°C while being mixed, and evaporated to dryness. The resulting dried product was then calcined. The calcination temperature was 600°C, and the calcination time was 2 hours.

[0146] In this way, strontium-loaded CeO2 (Sr / CeO2) was produced. The proportion of strontium relative to the total moles of strontium and CeO2 was 17.8 mol%.

[0147] Preparation example 3 (Al2O3) Commercially available Al2O3 (model number JRC-ALO-7, manufactured by Nikki Universal Co., Ltd.) was prepared.

[0148] Preparation Example 4 (Na / Al2O3) Al2O3 carrying sodium as an alkali metal (Na / Al2O3) was produced by the following method. Sodium nitrate was dissolved in distilled water to obtain a solution containing sodium. Next, Al2O3 was added to the sodium-containing solution, and the mixture was heated to 100°C while being mixed, and evaporated to dryness. The resulting dried product was then calcined. The calcination temperature was 600°C, and the calcination time was 2 hours.

[0149] In this way, sodium-loaded Al2O3 (Na / Al2O3) was produced. The ratio of sodium to the total moles of sodium and Al2O3 was 15 mol %.

[0150] Preparation example 5 (K / Al2O3) Al2O3 carrying potassium as an alkali metal (K / Al2O3) was produced by the following method. Specifically, potassium nitrate was dissolved in distilled water to obtain a solution containing potassium. Next, Al2O3 was added to the solution containing potassium, and the mixture was heated to 100°C while being mixed, and evaporated to dryness. The resulting dried product was then calcined. The calcination temperature was 600°C, and the calcination time was 2 hours.

[0151] In this way, potassium-loaded Al2O3 (K / Al2O3) was produced. The ratio of potassium to the total moles of potassium and Al2O3 was 15 mol %.

[0152] Preparation example 6 (Sr / Al2O3) Strontium-loaded Al2O3 (Sr / Al2O3) was produced by the following method. Strontium nitrate was dissolved in distilled water to obtain a solution containing strontium. Next, Al2O3 was added to the solution containing strontium, and the mixture was heated to 100°C while being mixed, and evaporated to dryness. The resulting dried product was then calcined. The calcination temperature was 600°C, and the calcination time was 2 hours.

[0153] In this way, strontium-loaded Al2O3 (Sr / Al2O3) was produced. The proportion of strontium relative to the total amount of strontium and Al2O3 was 11.5 mol %.

[0154] Preparation Example 7 (Zeolite) A commercially available zeolite (trade name Molecular Sieve 13X POWDER, manufactured by Union Showa Co., Ltd.) was prepared.

[0155] Examples 1 to 4 and Comparative Examples 1 to 3 According to Table 1, a carbon monoxide production system was manufactured using the carbon dioxide adsorbent material of each preparation example.

[0156] [Table 1]

[0157] More specifically, the carbon dioxide adsorption material was dispersed in water to obtain a slurry of the carbon dioxide adsorption material. The slurry of the carbon dioxide adsorption material was applied to the surface of each of the three electrode panels of the plasma reactor and then fired at 500°C. In this way, a carbon dioxide adsorption member made of the carbon dioxide adsorption material was laminated on each of the three electrode panels of the plasma reactor.

[0158] The total amount of carbon dioxide adsorption member on each opposing surface of each electrode panel was 0.33 g, which means that the total amount of carbon dioxide adsorption member on the two opposing surfaces of the three electrode panels was 0.66 g.

[0159] Next, the electrode panel was set in the plasma reactor, and the plasma reactor shown in FIG.

[0160] Then, the test gas was supplied to the casing of the plasma reactor, thereby causing carbon dioxide to be adsorbed by the carbon dioxide adsorption member. The supply of the test gas was continued until the amount of adsorbed carbon dioxide reached saturation.

[0161] The test gas used was a mixed gas of carbon dioxide and argon (Ar) (CO2+Ar, CO2 concentration 600 ppm). The supply rate of the mixed gas was 1 L / min.

[0162] Air was used as another test gas at a supply rate of 3 L / min.

[0163] Next, 100% Ar gas was supplied to the plasma reactor at a rate of 1 L / min, and a high-voltage pulse (power 30 W, power frequency 20 kHz) was applied to the electrode panels of the plasma reactor, generating plasma between the electrode panels and converting carbon dioxide to carbon monoxide.

[0164] Next, the gas to be treated was sampled at the outlet of the plasma reactor, and the carbon monoxide content was measured using a gas analyzer (NDIR; non-dispersive infrared absorption method). From this, the amount of carbon monoxide produced (mmol) was calculated.

[0165] The amount of carbon monoxide produced (mmol / g) per 1 g of the carbon dioxide adsorbing material was then calculated. The relationship between the carbon dioxide adsorbing material and the amount of carbon monoxide produced is shown in Figure 4. [Explanation of symbols]

[0166] 1 Carbon monoxide production system 3. Plasma reactor 4 Carbon dioxide supply line 5 Carbon monoxide exhaust line 30 Casing 31 Electrode Panel 35 Carbon dioxide adsorption material

Claims

[Claim 1] It is a carbon monoxide production system that converts carbon dioxide into carbon monoxide. a plasma reactor; a carbon dioxide supply line for supplying carbon dioxide to the plasma reactor; a carbon monoxide exhaust line for exhausting carbon monoxide from the plasma reactor; The plasma reactor comprises: A casing; a plurality of electrode panels and a carbon dioxide adsorption member disposed within the casing; Equipped with The carbon dioxide adsorption member is CeO ２ and, Strontium-loaded CeO ２ and, Alkali metal-supported Al ２ O ３ and A carbon monoxide production system comprising at least one selected from the group consisting of:

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