Chemical reaction apparatus

Abstract

To provide a chemical reaction apparatus to make the flow of an electrolyte uniform.SOLUTION: A chemical reaction apparatus 100 comprises a container 110 and a rectifying plate 106 for rectifying the flow of an electrolyte 108 on the reaction surfaces of an oxidation electrode 102 and a reduction electrode 104. In the container, one or more outlets 110b are provided for discharging the electrolyte 108 aside from an exhaust port 110c for exhausting gas generated by reaction. The outlet 110b is provided in a lower position than the exhaust port 110c in the vertical direction. The liquid level of the electrolyte 108 is arranged in a lower position than the exhaust port 110c. The maximum value of an angle θ, which is the angle between the vertical line and a line connecting each point of the top edge on the reaction surface in the vertical direction to the rim of the outlet 110b positioned in the shortest distance from the point, is 30 degrees or larger and 84 degrees or smaller. The height from the top edge of the reaction surface to the rim of the outlet 110b is the diameter of the outlet 110b of more.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a chemical reaction apparatus.

Background Art

[0002] A chemical reaction apparatus is disclosed in which a reduction reaction electrode and an oxidation reaction electrode are spaced apart and opposed in a container, and a substance (reaction substrate) contained in an electrolytic solution is chemically reacted by allowing the electrolytic solution to flow between the reduction reaction electrode and the oxidation reaction electrode (Patent Document 1). Further, a configuration in which units of a plurality of photoelectrochemical reaction cells are connected in series and in parallel is disclosed (Patent Document 2).

[0003] By the way, in order to improve the reaction efficiency in a chemical reaction apparatus, it is required to prevent the backflow of the electrolytic solution between the opposed reduction reaction electrode and oxidation reaction electrode, and to make the flow of the electrolytic solution as uniform as possible. Therefore, in such a chemical reaction apparatus, in order to make the flow of the electrolytic solution uniform, it is provided with an exhaust port for discharging the gas generated by the reaction from the container, and an overflow port for discharging the liquid from the container separately from the exhaust port, and the overflow port is arranged at a position lower than the exhaust port along the vertical direction (Patent Document 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the prior art, no configuration has been shown that sufficiently considers the influence of the number and arrangement of the electrolyte discharge ports on the flow of the electrolyte. Therefore, it is required to uniformize the flow by providing a plurality of discharge ports at appropriate positions.

[0006] In addition, when the number of the electrolyte discharge ports increases, the number of peripheral components such as pipes connected to each discharge port also increases, and the manufacturing cost of the chemical reaction device increases. Therefore, it is preferable to minimize the number of the discharge ports.

[0007] Furthermore, in order to increase the reaction area of the reduction reaction electrode and the oxidation reaction electrode, it is necessary to ensure sufficient height of the chemical reaction device. However, if the height is increased more than necessary, it will lead to an increase in the size of the device. In order to avoid an increase in the size of the chemical reaction device, it is preferable to bring the electrolyte discharge port closer to the upper ends of the reduction reaction electrode and the oxidation reaction electrode. However, in the prior art, the influence of the number and arrangement of the electrolyte discharge ports on the flow of the electrolyte has not been sufficiently considered, and the optimization of how close the electrolyte discharge port can be to the upper ends of the reduction reaction electrode and the oxidation reaction electrode has not been carried out.

Means for Solving the Problems

[0008] One aspect of the present invention is a chemical reaction device that supplies a liquid between electrodes disposed in a container and reacts substances contained in the liquid, wherein the container is provided with one or more discharge ports for discharging the liquid separately from an exhaust port for discharging a gas generated by the reaction, the discharge port is provided at a position lower than the exhaust port in the vertical direction, the liquid level of the liquid is at a position lower than the exhaust port, and a rectifying plate for adjusting the flow of the liquid is provided on the reaction surface of the electrode, and the maximum value of the angle formed by a line connecting each position at the upper end of the reaction surface in the vertical direction and the edge of the discharge port at the shortest distance from each position and a line along the vertical direction is 30° or more and 84° or less, and the height from the upper end of the reaction surface to the edge of the discharge port is equal to or greater than the diameter of the discharge port.

[0009] Another aspect of the present invention is a chemical reaction apparatus that supplies a liquid between electrodes disposed in a container and reacts substances contained in the liquid. The container is provided with one or more outlets for discharging the liquid separately from an exhaust port for discharging a gas generated by the reaction. The outlet is provided at a position lower than the exhaust port in the vertical direction, the liquid level of the liquid is at a position lower than the exhaust port, and the reaction surface of the electrode is provided with a flow rectifying plate for rectifying the flow of the liquid. The maximum value of the angle formed by a line connecting each location at the upper end of the reaction surface in the vertical direction and the edge of the outlet at the shortest distance from each location and a line along the vertical direction is 30° or more and 70° or less, and the height from the upper end of the reaction surface to the edge of the outlet is 1.6 times or more the diameter of the outlet. This is a chemical reaction apparatus characterized by this.

[0010] Here, the electrodes are an electrode for reduction reaction and an electrode for oxidation reaction, and it is preferable that the electrode for reduction reaction and the electrode for oxidation reaction are arranged at positions where they are separated and opposed to each other.

[0011] Further, the liquid is an electrolytic solution, and it is preferable that the gas is generated along with the reaction at at least one of the electrode for reduction reaction and the electrode for oxidation reaction. Further, the substance is carbon dioxide (CO2), and it is preferable that carbon dioxide (CO2) is reduced at the electrode for reduction reaction and oxygen (O2) is generated at the electrode for oxidation reaction.

[0012] Further, it is preferable that a plurality of the electrodes for reduction reaction and a plurality of the electrodes for oxidation reaction are alternately laminated.

Effects of the Invention

[0013] According to the present invention, a chemical reaction apparatus with a uniform flow of electrolytic solution can be provided.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0015] As shown in the perspective schematic view of FIG. 1 and the cross-sectional schematic view of FIG. 2, the chemical reaction apparatus 100 in the embodiment of the present invention includes an electrode 102 for oxidation reaction, an electrode 104 for reduction reaction, a rectifying plate 106, an electrolytic solution 108, a container 110, and an orifice plate 112.

[0016] The chemical reaction apparatus 100 is arranged and used such that the Z direction in the figure is the vertical direction. Note that FIG. 2 shows a cross-sectional view of the chemical reaction apparatus 100 in a state where the electrolytic solution 108 is supplied, cut along the Y-Z plane.

[0017] The container 110 is a member that supports the oxidation reaction electrode 102, the reduction reaction electrode 104, and the rectifying plate 106, and forms a flow path through which the electrolytic solution 108 flows. The container 110 is made of a material having the mechanical strength necessary to configure the chemical reaction apparatus 100 as a cell. For example, the container 110 can be made of metal, plastic, or the like.

[0018] The container 110 is provided with a supply port 110a for supplying the electrolytic solution 108 into the container 110. Further, a discharge port 110b for discharging the electrolytic solution 108 from the container 110 is provided. That is, the electrolytic solution 108 containing the reaction substrate is supplied into the container 110 through the supply port 110a, the electrolytic solution 108 is circulated through the reaction region between the oxidation reaction electrode 102 and the reduction reaction electrode 104, and then the electrolytic solution 108 is discharged from the discharge port 110b to the outside of the container 110.

[0019] In addition, the container 110 is provided with an exhaust port 110c for discharging the gas generated by the reaction in the chemical reaction device 100 from the container 110. The supply port 110a is preferably arranged below the reaction region where the oxidation reaction electrode 102 and the reduction reaction electrode 104 are arranged in the container 110 along the vertical direction. Further, the exhaust port 110c is preferably arranged above the reaction region where the oxidation reaction electrode 102 and the reduction reaction electrode 104 are arranged in the container 110 along the vertical direction.

[0020] The discharge port 110b of the electrolytic solution 108 is preferably arranged above the upper ends of the oxidation reaction electrode 102 and the reduction reaction electrode 104 in the vertical direction (Z direction) so that the oxidation reaction electrode 102 and the reduction reaction electrode 104 can sufficiently contribute to the reaction with respect to the electrolytic solution 108 supplied into the container 110. Thereby, the electrolytic solution 108 can be discharged from the discharge port 110b while the entire oxidation reaction electrode 102 and reduction reaction electrode 104 are immersed in the electrolytic solution 108. The exhaust port 110c is preferably provided at a position higher than the discharge port 110b along the vertical direction (Z direction).

[0021] The oxidation reaction electrode 102 and the reduction reaction electrode 104 are each plate-shaped members extending in the X and Z directions, and are arranged side by side so as to face each other along the Y direction. In the present embodiment, two oxidation reaction electrodes 102 with the catalyst supported on one side, three oxidation reaction electrodes 102 with the catalyst supported on both sides, four reduction reaction electrodes 104 with the catalyst supported on both sides, and reaction surfaces extending in the X-Z plane direction on which the oxidation catalyst and the reduction catalyst are supported are arranged so as to face each other. That is, along the Y direction in FIG. 2, from the left side, the oxidation reaction electrode 102 with the catalyst supported on one side, the rectifying plate 106, and the reduction reaction electrode 104 with the catalyst supported on both sides, the rectifying plate 106, and the oxidation reaction electrode 102 with the catalyst supported on both sides, the rectifying plate 106, and the reduction reaction electrode 104 with the catalyst supported on both sides, the rectifying plate 106, and the oxidation reaction electrode 102 with the catalyst supported on both sides... The oxidation reaction electrode 102 with the catalyst supported on one side is arranged. Thus, a plurality of oxidation reaction electrodes 102, a plurality of rectifying plates 106, and a plurality of reduction reaction electrodes 104 are laminated along the Y direction.

[0022] The reduction reaction electrode 104 is an electrode used to reduce a substance by a reduction reaction. The reduction reaction electrode 104 is formed on the substrate 114 as shown in the cross-sectional view of FIG. 3. The reduction reaction electrode 104 includes a conductive layer 10 and a reduction catalyst layer 12.

[0023] The substrate 114 is a member that structurally supports the reduction reaction electrode 104. The material of the substrate 114 is not particularly limited, but for example, it is a glass substrate or the like. Further, the substrate 114 may contain, for example, a metal or a semiconductor. The metal used as the substrate 114 is not particularly limited, but it is preferably one containing titanium (Ti), silver (Ag), gold (Au), copper (Cu), zinc (Zn), indium (In), cadmium (Cd), tin (Sn), palladium (Pd), lead (Pb). The semiconductor used as the substrate 114 is not particularly limited, but it is preferably one such as titanium dioxide (TiO2), tin dioxide (SnO2), silicon (Si), strontium titanate (SrTiO3), zinc oxide (ZnO), tantalum pentoxide (Ta2O5).

[0024] When the substrate 114 is an insulator, a conductive layer 10 is provided between the substrate 114 and the reduction catalyst layer 12. The conductive layer 10 is provided to apply a voltage to the reduction catalyst layer 12 of the reduction reaction electrode 104. The conductive layer 10 is not particularly limited, but it is preferably a transparent conductive layer such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), or zinc oxide (ZnO). In particular, considering thermal and chemical stability, it is preferable to use fluorine-doped tin oxide (FTO).

[0025] The reduction catalyst layer 12 is composed of a material having a reduction catalyst function. The reduction catalyst layer 12 preferably contains a complex catalyst. The reduction catalyst layer 12 is preferably a ruthenium complex, for example. The complex catalyst can be, for example, [Ru{4,4’-di(1-H-1-pyrrolypropyl carbonate)-2,2’-bipyridine}(CO)(MeCN)Cl2], [Ru{4,4’-di(1-H-1-pyrrolypropyl carbonate)-2,2’-bipyridine}(CO)2Cl2], [Ru{4,4’-di(1-H-1-pyrrolypropyl carbonate)-2,2’-bipyridine}(CO)2] n , [Ru{4,4’-di(1-H-1-pyrrolypropyl carbonate)-2,2’-bipyridine}(CO)(CH3CN)Cl2], etc.

[0026] The modification by the complex catalyst can be made by applying a solution in which the complex is dissolved in an acetonitrile (MeCN) solution onto the conductive layer 10. Also, the modification by the complex catalyst can be performed by an electrolytic polymerization method. Using the electrode of the conductive layer 10 as the working electrode, a glass substrate coated with fluorine-containing tin oxide (FTO) as the counter electrode, and an Ag / Ag + electrode, and flowing a cathodic current so as to be a negative voltage with respect to the Ag / Ag + electrode in an electrolytic solution containing the complex catalyst, and then Ag / Ag +By flowing an anodic current so as to make it a positive potential with respect to the electrode, the surface of the conductive layer 10 can be modified with a complex catalyst. As the solution of the electrolyte, acetonitrile (MeCN) can be used, and as the electrolyte, Tetrabutylammonium perchlorate (TBAP) can be used.

[0027] Further, the reduction catalyst layer 12 can be configured to include a conductor containing a carbon material (C). It is preferable that the size of the single structure of the carbon material is 1 nm or more and 1 μm or less. The carbon material preferably includes at least one of, for example, carbon nanotubes, graphene, and graphite. In the case of graphene and graphite, it is preferable that the size is 1 nm or more and 1 μm or less. In the case of carbon nanotubes, it is preferable that the diameter is 1 nm or more and 40 nm or less. The conductor can be formed by spraying a carbon material mixed in a liquid such as ethanol and heating it. Instead of spraying, it may be applied by spin coating. Further, without using spin coating, the solution may be directly dropped and dried for coating.

[0028] As a method for supporting the reduction catalyst in the reduction catalyst layer 12, for example, a solution in which a metal complex (catalyst) is dissolved in an acetonitrile (MeCN) solution (for example, an Ru complex polymer solution) is applied onto a carbon-based material such as carbon paper or carbon cloth and dried, whereby it can be produced. Further, the reduction catalyst can also be supported by an electropolymerization method. For example, using a carbon-based material electrode as the working electrode, a glass substrate coated with fluorine-doped tin oxide (FTO) as the counter electrode, and an Ag / Ag + electrode, in an electrolytic solution containing a reduction catalyst, after flowing a cathodic current so as to make it a negative voltage with respect to the Ag / Ag + electrode, and then flowing an anodic current so as to make it a positive potential with respect to the Ag / Ag + electrode, the carbon-based material can be supported with a reduction catalyst. As the solution of the electrolyte, for example, acetonitrile (MeCN) can be used, and as the electrolyte, for example, Tetrabutylammonium perchlorate (TBAP) can be used.

[0029] In FIG. 3, an example in which the conductive layer 10 and the reduction catalyst layer 12 are formed only on one surface of the substrate 114 is shown. However, the conductive layer 10 and the reduction catalyst layer 12 may be formed on both surfaces of the substrate 114.

[0030] The oxidation reaction electrode 102 is an electrode used to oxidize a substance by an oxidation reaction. As shown in the cross-sectional view of FIG. 4, the oxidation reaction electrode 102 is formed on a substrate 116. The oxidation reaction electrode 102 includes a conductive layer 14 and an oxidation catalyst layer 16.

[0031] The substrate 116 is a member that structurally supports the oxidation reaction electrode 102. The substrate 116 can be made of the same material as the substrate 114 used for the reduction reaction electrode 104.

[0032] The conductive layer 14 is provided to effectively collect electricity in the oxidation reaction electrode 102. The conductive layer 14 is not particularly limited, but it is preferably indium tin oxide (ITO), fluorine-doped tin oxide (FTO), zinc oxide (ZnO), or the like. In particular, considering thermal and chemical stability, it is preferable to use fluorine-doped tin oxide (FTO).

[0033] The oxidation catalyst layer 16 is composed of a material having an oxidation catalyst function. The material having an oxidation catalyst function can be, for example, a material containing iridium oxide (IrOx). Iridium oxide can be supported on the surface of the conductive layer 14 as a nanocolloid solution (T. Arai et.al, Energy Environ. Sci 8, 1998 (2015)).

[0034] For example, synthesize iridium oxide (IrOx) nanoparticles. First, add a 10 wt% aqueous sodium hydroxide (NaOH) solution to 50 ml of a 2 mM aqueous potassium hexachloroiridate(IV) (K2IrCl6) solution to adjust the pH to 13, obtaining a yellow solution. Heat this yellow solution at 90 °C for 20 minutes using a hot stirrer. Cool the resulting blue solution in ice water for 1 hour. Then, add 3 M nitric acid (HNO3) dropwise to the cooled solution (20 ml) to adjust the pH to 1, stir for 80 minutes, and obtain an aqueous solution of iridium oxide (IrOx) nanoparticles. Further, add a 1.5 wt% NaOH aqueous solution (1 - 2 ml) dropwise to this solution to adjust the pH to 12. The thus-obtained aqueous solution of iridium oxide (IrOx) nanoparticles is applied onto the conductive layer 14 at pH 12 and held in a drying oven at 60 °C for 40 minutes to dry. After drying, wash the precipitated salt with ultrapure water to form the oxidation reaction electrode 102. Note that the application and drying of the aqueous solution of iridium oxide (IrOx) nanoparticles may be repeated a plurality of times.

[0035] Note that in FIG. 4, an example is shown in which the conductive layer 14 and the oxidation catalyst layer 16 are formed only on one surface of the substrate 116, but the conductive layer 14 and the oxidation catalyst layer 16 may be formed on both surfaces of the substrate 116.

[0036] The rectifying plate 106 is a member that partitions the space between the oxidation reaction electrode 102 and the reduction reaction electrode 104 to regulate the flow of the electrolyte 108. The rectifying plate 106 is a plate-like member extending along the direction (Z direction) from the supply port 110a of the electrolyte to the discharge port 110b. The rectifying plates 106 are arranged in a plurality along the X direction such that the plate surface is along the Y direction. Thereby, the flow of the electrolyte 108 along the direction (X direction) intersecting the Y direction is restricted, and the flow of the electrolyte 108 can be regulated in the direction (Z direction) from the supply port 110a to the discharge port 110b.

[0037] The chemical reaction device 100 functions by introducing an electrolytic solution 108 between the reduction reaction electrode 104 and the oxidation reaction electrode 102. That is, the reduction reaction electrode 104 and the oxidation reaction electrode 102 are housed in a container 110, and the electrolytic solution 108 in which the reaction substrate is dissolved is supplied to the surfaces of the reduction reaction electrode 104 and the oxidation reaction electrode 102.

[0038] The reaction substrate can be a carbon compound, for example, it can be carbon dioxide (CO2). Also, the electrolytic solution 108 is preferably a phosphate buffer aqueous solution or a borate buffer aqueous solution. In a specific configuration example, a tank of carbon dioxide (CO2) saturated phosphate buffer is provided, and the electrolytic solution 108 is supplied from the supply port 110a to the surfaces of the reduction reaction electrode 104 and the oxidation reaction electrode 102 by a pump. The formic acid (HCOOH) generated by the reduction reaction is recovered from the discharge port 110b to an external fuel tank together with the electrolytic solution 108, and at the same time, the oxygen (O2) generated by the oxidation reaction is discharged from the exhaust port 110c.

[0039] A bias power supply may be provided between the oxidation reaction electrode 102 and the reduction reaction electrode 104 to apply a potential difference between the oxidation reaction electrode 102 and the reduction reaction electrode 104. The bias power supply can be, for example, a solar cell. When a solar cell is adopted as the bias power supply, the solar cell can be arranged adjacent to the container 110. For example, a solar cell can be arranged on the back surface of the container 110, the positive electrode of the solar cell can be connected to the oxidation reaction electrode 102, and the negative electrode can be connected to the reduction reaction electrode 104.

[0040] When synthesizing formic acid (HCOOH) etc. from carbon dioxide (CO2), water (H2O) is oxidized to supply electrons and protons to carbon dioxide (CO2). At around pH 7, the oxidation potential of water (H2O) is 0.82V and the reduction potential is -0.41V (both are NHE). Also, the reduction potentials from carbon dioxide (CO2) to carbon monoxide (CO), formic acid (HCOOH), and methyl alcohol (CH3OH) are -0.53V, -0.61V, and -0.38V respectively. Therefore, the potential difference between the oxidation potential and the reduction potential is 1.20 - 1.43V.

[0041] Furthermore, an orifice plate 112 is provided in the chemical reaction apparatus 100. The orifice plate 112 is a plate-like member provided with orifice holes which are through-holes for restricting the flow of the electrolytic solution 108 introduced from the supply port 110a into the container 110. The orifice plate 112 is disposed on the flow path in the container 110 leading to the region where the oxidation reaction electrode 102 and the reduction reaction electrode 104 are provided from the supply port 110a. The orifice plate 112 is made of a material having necessary mechanical strength. For example, the orifice plate 112 can be made of metal, plastic, or the like.

[0042] In the chemical reaction apparatus 100, the space formed by the oxidation reaction electrode 102, the reduction reaction electrode 104, and the rectifying plate 106 serves as a flow path for the electrolytic solution 108 to flow. The orifice plate 112 is disposed between the supply port 110a and these flow paths. The orifice plate 112 is provided with orifice holes connecting the flow path formed by the oxidation reaction electrode 102, the reduction reaction electrode 104, and the rectifying plate 106 and the supply port 110a. The diameter of the orifice holes may be, for example, 0.5 mm, and the interval may be, for example, 10 mm.

[0043] Therefore, the electrolytic solution 108 supplied from the supply port 110a is stored in the space from the supply port 110a to the orifice plate 112, and then is ejected through the orifice holes of the orifice plate 112 into the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104. When the electrolytic solution 108 flows into the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104, the flow path is filled with the electrolytic solution 108. Furthermore, the electrolytic solution 108 is discharged from the container 110 through the discharge port 110b.

[0044] In this embodiment, a separator may be further provided. The separator is a member that partitions between the oxidation reaction electrode 102 and the reduction reaction electrode 104. The separator can be constituted by a proton-conducting film which is a porous body capable of transmitting protons in the electrolytic solution 108. The separator can be constituted by, for example, a rayon nonwoven fabric, a vinylon nonwoven fabric, a hydrophilized ultrahigh molecular weight polyethylene porous film, a hydrophilized polypropylene mesh, or a hydrophilized ultrahigh molecular weight polyethylene porous film. Further, the separator may be integrated with the rectifying plate 106.

[0045] <Example> An example of the chemical reaction apparatus 100 in the embodiment of the present invention will be described below. In the example, an oxidation reaction electrode 102 and a reduction reaction electrode 104 were provided, and nine rectifying plates 106 were arranged between the respective oxidation reaction electrodes 102 and reduction reaction electrodes 104. Further, in the chemical reaction apparatus 100, an orifice plate 112 was provided between the supply port 110a of the electrolytic solution 108 and the oxidation reaction electrode 102 and the reduction reaction electrode 104.

[0046] The sizes of the oxidation reaction electrode 102 and the reduction reaction electrode 104 were 1 m square. Note that the inner dimension W in the lateral direction (X direction) of the container 110 was 1078 mm, the inner dimension T2 in the thickness direction (Y direction) was 166 mm, and the size was such that a maximum of 14 pairs of the oxidation reaction electrode 102 and the reduction reaction electrode 104 could be installed.

[0047] For the oxidation reaction electrode 102, a Ti plate coated with IrOx colloid and dried was used. For the reduction reaction electrode 104, a carbon paper / multi-walled carbon nanotube supporting a Ru complex polymer and attached to a titanium substrate using a carbon-based adhesive was used.

[0048] The oxidation reaction electrode 102 and the reduction reaction electrode 104 were arranged in the container 110 with their reaction surfaces carrying a catalyst facing each other. The electrolytic solution 108 was a 0.4 M phosphate buffer solution in which CO2 was saturated and dissolved by bubbling in a separate container. A crystalline silicon solar cell was connected to the oxidation reaction electrode 102 and the reduction reaction electrode 104 as a DC power source, and light was irradiated to apply a voltage.

[0049] FIG. 5 is a diagram for explaining the arrangement of the discharge port 110b in the examples. In the examples and comparative examples, the discharge port 110b was circular.

[0050] FIG. 6 shows the configuration and test results of the chemical reaction apparatus 100 in Examples 1 to 13 and Comparative Example 1. Here, at the upper end of the reaction surfaces of the oxidation reaction electrode 102 and the reduction reaction electrode 104, an angle θ formed between a line Q connecting the point P farthest from the discharge port 110b and the edge of the discharge port 110b and the vertical direction (Z direction) (the maximum angle θ formed between a line connecting each location at the upper end of the reaction surfaces of the oxidation reaction electrode 102 and the reduction reaction electrode 104 and the edge of the discharge port 110b at the shortest distance therefrom and the vertical direction (Z direction)), the diameter D of the discharge port 110b, and the distance L from the upper end of the reaction surfaces of the oxidation reaction electrode 102 and the reduction reaction electrode 104 to the edge of the discharge port 110b are defined. Also, the discharge port 110b was arranged evenly with respect to the lateral width of the reaction surfaces of the oxidation reaction electrode 102 and the reduction reaction electrode 104.

[0051] For example, in Example 1, eight pairs of oxidation reaction electrodes 102 and reduction reaction electrodes 104 were arranged in the container 110. The total thickness (thickness T1 in FIG. 2) of the oxidation reaction electrode 102 and the reduction reaction electrode 104 was 94 mm. Also, the number of discharge ports 110b was 10, the angle θ was 29°, and the ratio L / D of the distance L to the diameter D was 9.29.

[0052] FIG. 7 shows the result of fluid analysis of the flow velocity distribution of the electrolytic solution 108 for Example 1. The chemical reaction apparatus 100 shown in FIG. 1 has a size of 1 m square, and two discharge ports 110b are provided. Since it has a symmetric structure, in Examples 1 to 13 and Comparative Example 1, a configuration was used in which one discharge port 110b was provided at the upper left side with a size of 50 cm square divided into four parts. Assuming that the flow velocity distribution is uniform at the lower end of the 50 cm square size, the analysis was performed.

[0053] In the flow path between the stacked oxidation reaction electrode 102 and reduction reaction electrode 104, the standard deviation of the flow velocity at a position 10 mm below the upper end of the reaction surface (the position of the broken line in FIG. 7) was 2.30×10 -3 L / min to 2.91×10 -3 L / min. Also, the value obtained by dividing the average of the standard deviation of the flow velocity of the electrolytic solution 108 by the flow rate was 7.14×10 -5 . That is, in Example 1, the flow velocity of the electrolytic solution 108 was substantially uniform in the container 110. Also, no phenomenon of backflow of the electrolytic solution 108 was observed in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104 closest to the discharge port 110b.

[0054] Similarly, as shown in FIG. 8, in Examples 2 to 13 as well, the value obtained by dividing the average of the standard deviation of the flow velocity of the electrolytic solution 108 by the flow rate was on the order of 10 -5 . That is, in Examples 2 to 13, the flow velocity of the electrolytic solution 108 was substantially uniform in the container 110. Also, no phenomenon of backflow of the electrolytic solution 108 was observed in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104 closest to the discharge port 110b.

[0055] From the analysis results of Examples 1 to 13, if the angle θ is 30° or more and 70° or less, and the distance L is 1.6 times or more the diameter D, then the value obtained by dividing the average of the standard deviation of the flow velocity of the electrolytic solution 108 by the flow rate in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104 can be kept at 7.73×10 -5 or less. Also, in this case, no backflow of the electrolytic solution 108 occurs in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104.

[0056] Furthermore, from the analysis results of Examples 1 to 8, if the angle θ is 30° or more and 84° or less, and the distance L is 1.0 times or more the diameter D, the average of the standard deviation of the flow velocity of the electrolytic solution 108 in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104 is divided by the flow rate. The value can be kept below 1.03×10 -4 In addition, in this case, reverse flow of the electrolytic solution 108 does not occur in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104.

[0057] On the other hand, when the angle θ is 88° and the distance L is 0.03 times the diameter D as in Comparative Example 1, the value obtained by dividing the average of the standard deviation of the flow velocity of the electrolytic solution 108 in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104 by the flow rate is 2.72×10 -4 resulting in a value of 1.03×10 -4 or more. That is, in Comparative Example 1, the flow velocity of the electrolytic solution 108 in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104 became non-uniform compared to Examples 1 to 13. Also, in this case, reverse flow of the electrolytic solution 108 was observed in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104.

[0058] As described above, since the analysis was performed on a 50 cm square size for the 1 m square sized chemical reaction apparatus 100, in the case of a 1 m square size, even if the analysis results shown in FIG. 7 are arranged side by side and there are two discharge ports 110b, the same results can be obtained. Furthermore, when the size is 1.5 m square, the analysis results shown in FIG. 7 may be further arranged and there may be three discharge ports 110b. That is, if the angle θ and the distance L satisfy predetermined conditions, the flow velocity of the fluid can be made uniform, so the number of discharge ports 110b can be selected according to the allowable range of the distance L defined by the width of the container 110 or the oxidation reaction electrode 102, the reduction reaction electrode 104, and the size of the chemical reaction apparatus 100. For example, if the width is narrow and the allowable value of the distance L is large, the number of discharge ports 110b can be set to one, and if the width is wide and the allowable range of the distance L is small, the number of discharge ports 110b can be increased.

[0059] As described above, according to the present embodiment, in the chemical reaction apparatus 100, while suppressing the height of the container 110, it is possible to make the flow velocity of the fluid uniform in the flow path between the oxidation reaction electrode 102 and the reduction reaction electrode 104.

Explanation of symbols

[0060] 10 Conductive layer, 12 Reduction catalyst layer, 14 Conductive layer, 16 Oxidation catalyst layer, 100 Chemical reaction apparatus, 102 Oxidation reaction electrode, 104 Reduction reaction electrode, 106 Rectifying plate, 108 Electrolyte, 110 Container, 110a Supply port, 110b Discharge port, 110c Exhaust port, 112 Orifice plate, 114 Substrate, 116 Substrate.

Claims

1. A chemical reaction apparatus for supplying a liquid between electrodes disposed in a container and reacting substances contained in the liquid, wherein the container is provided with one or more circular discharge ports for discharging the liquid separately from an exhaust port for discharging a gas generated by the reaction, the discharge port is provided at a position lower than the exhaust port in the vertical direction, and the liquid level of the liquid is at a position lower than the exhaust port, the reaction surface of the electrode is provided with a rectifying plate for rectifying the flow of the liquid, the maximum value of the angle formed by a line connecting each location at the upper end of the reaction surface in the vertical direction and the edge of the discharge port at the shortest distance from each location and a line along the vertical direction is 30° or more and 84° or less, a chemical reaction apparatus, characterized in that the height from the upper end of the reaction surface to the edge of the discharge port is equal to or greater than the diameter of the discharge port.

2. A chemical reaction apparatus for supplying a liquid between electrodes disposed in a container and reacting substances contained in the liquid, wherein the container is provided with one or more circular discharge ports for discharging the liquid separately from an exhaust port for discharging a gas generated by the reaction, the discharge port is provided at a position lower than the exhaust port in the vertical direction, and the liquid level of the liquid is at a position lower than the exhaust port, the reaction surface of the electrode is provided with a rectifying plate for rectifying the flow of the liquid, the maximum value of the angle formed by a line connecting each location at the upper end of the reaction surface in the vertical direction and the edge of the discharge port at the shortest distance from each location and a line along the vertical direction is 30° or more and 70° or less, a chemical reaction apparatus, characterized in that the height from the upper end of the reaction surface to the edge of the discharge port is 1.6 times or more the diameter of the discharge port.

3. The chemical reaction apparatus according to claim 1 or 2, wherein the electrodes are a reduction reaction electrode and an oxidation reaction electrode, a chemical reaction apparatus, characterized in that the reduction reaction electrode and the oxidation reaction electrode are disposed at positions facing each other with a gap therebetween.

4. The chemical reaction apparatus according to claim 3, wherein the liquid is an electrolytic solution, a chemical reaction apparatus, characterized in that the gas is generated by a reaction in at least one of the reduction reaction electrode and the oxidation reaction electrode.

5. The chemical reaction apparatus according to claim 4, The substance is carbon dioxide (CO ２ ), and In the electrode for the reduction reaction, carbon dioxide (CO ２ ) is reduced, and in the electrode for the oxidation reaction, oxygen (O ２ ) is generated. A chemical reaction apparatus characterized by this.

6. The chemical reaction apparatus according to any one of claims 3 to 5, a chemical reaction apparatus, characterized in that a plurality of the reduction reaction electrodes and a plurality of the oxidation reaction electrodes are alternately laminated.

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