Co2 Electrolysis Device

Priority is claimed on Japanese Patent Application No. 2024-046463, filed Mar. 22, 2024, the content of which is incorporated herein by reference.

The present invention relates to a COelectrolysis device.

Efforts aimed at mitigating or reducing the impact of climate change have been ongoing in the related art, and research and development into reducing COemissions is being carried out to achieve this goal.

The technology of recovering COfrom exhaust gas or the atmosphere and obtaining valuable products through electrochemical reduction is a promising technology with the potential to achieve carbon neutrality, but the biggest challenge is economic efficiency. In order to improve the economic efficiency, it is important to increase the energy efficiency and reduce the loss of COin the recovery and reduction of CO.

As the technique of recovering CO, for example, Japanese Unexamined Patent Application, First Publication No. 2022-151866 discloses that, by making the pH of a cathode-side electrolyte used in an electrochemical reactor higher than that of the anode-side electrolyte and suppressing hydrogen generation at the cathode, compared to the case where COis adsorbed onto an adsorbent and then desorbed and reduced by heating, the energy required to desorb COcan be reduced, energy efficiency can be improved, and COloss can also be reduced.

Incidentally, in order to reduce COemissions, it is necessary to further increase the size of COrecovery devices in order to further increase the recovery efficiency of CO.

As shown inand, an electrochemical reactor (a COelectrolytic laminate) disclosed in Japanese Unexamined Patent Application, First Publication No. 2022-151866 includes end platesprovided on both ends in a lamination direction, boltsinserted through a plurality of bolt holesand nuts, constituting a COelectrolysis device. By fastening the boltsand the nuts, the end platescome into contact with the COelectrolytic laminate, and a pressure is applied to the COelectrolytic laminate.

When the pressure is applied to the COelectrolytic laminate, current flows in a COelectrolysis cell, and a chemical reaction can be promoted. However, when the COelectrolysis deviceis increased in size, since only end portions of the end platesare fastened by the boltsand the nuts, as emphasized by the two-dot chain line in, central portions of the end platesmay bend outward in a lamination direction, making it impossible to apply sufficient pressure to the COelectrolytic laminate. When there are any parts of the COelectrolytic laminatethat do not receive sufficient pressure, sufficient current may not flow through those parts, and reaction efficiency in the COelectrolysis cellmay decrease.

One way to solve this problem is to use thicker end platesto increase rigidity and reduce deflection in the central portion. However, this will result in problems such as increased costs due to the increased amount of material used for the end platesand an increase in the weight of the COelectrolysis device, including the COelectrolytic laminate.

An aspect of the present invention is directed to providing a COelectrolysis device with improved recovery efficiency of CO. The aspect of the present invention contributes to mitigating or reducing the impact of climate change.

The summary of the present invention is as follows.

According to the aspect of the present invention, it is possible to provide a COelectrolysis device with improved recovery efficiency of CO.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Further, dimensions of the drawings illustrated in the following description are merely examples, and the present invention is not necessarily limited to them, and can be modified as appropriate within the scope that does not change the scope of the invention.

As shown inand, a COelectrolysis deviceaccording to the embodiment includes a COelectrolytic laminateconstituted by a plurality of COelectrolysis cells, which are laminated, end platesprovided on both ends of the COelectrolytic laminatein a lamination direction, and collarsprovided on both ends in a first direction perpendicular to the lamination direction of the COelectrolytic laminateand disposed between the end plates.

Here, the lamination direction in the embodiment is a direction perpendicular to the paper surface inand, and an upward/downward direction parallel to the paper surface in. In addition, the first direction perpendicular to the lamination direction is a leftward/rightward direction parallel to the paper sheet ofand. In an example shown into, the first direction coincides with a longitudinal direction of the COelectrolytic laminate.

The collarsare longer in the lamination direction than the COelectrolytic laminate. For this reason, for example, when boltsand nutsare fastened in sequence as shown in, the end platesare bent inward in the lamination direction at the central portion in the first direction of the COelectrolytic laminate, as emphasized by the two-dot chain line in. Accordingly, a pressure stronger than that applied to both end portions of the COelectrolytic laminatein the first direction can be applied to the COelectrolytic laminate. Here, it is preferable to use the end plateswith low rigidity so that the central portion of the COelectrolytic laminatein the first direction can bend inward in the lamination direction.

With the configuration described above, in the COelectrolysis deviceaccording to this embodiment, even if the device is enlarged, the central portions of the end platesare prevented from bending outward in the lamination direction, and a sufficient pressure can be applied to the COelectrolytic laminate. For this reason, it is possible to prevent a decrease in reaction efficiency in the COelectrolysis cells.

In addition, since it is not necessary to use thick end platesto increase rigidity, an increase in the amount of material required for the end platescan be prevented. Further, when the end plateswith lower rigidity are used, the material amount and weight of the end platescan be reduced.

Further, the collarsare preferably several um units longer than the COelectrolytic laminateso that a sufficient pressure is applied to both end portions of the COelectrolytic laminatein the first direction. By making the length of the collarsnot too long, but by making them longer by a few um units, it is possible to prevent the pressure from being applied to the COelectrolytic laminateat both end portions in the first direction.

As shown inand, the COelectrolysis devicemay be a rectangular parallelepiped with a longitudinal direction or may be a cube. When the COelectrolysis deviceis a rectangular parallelepiped, for example, the dimensions may be approximately 300 mm in the longitudinal direction and 100 mm in the lateral direction.

In the COelectrolysis deviceaccording to the embodiment, as shown inand, the end platesmay have a plurality of bolt holesand when the boltsinserted into the bolt holesare fastened to the nuts, the end platesmay have a shape that is bent inward in the lamination direction.

As described above, by tightening the boltsand the nutsin the order shown in, the end platescan be preferably bent inward in the lamination direction.

Further, in, a distinction is shown between bolt holeswhich do not have the collarsdisposed between them, and bolt holeswhich have the collarsdisposed between them. In addition, in, only some of the boltsand the nutsare shown.

In addition, in the COelectrolysis deviceaccording to the embodiment, as shown in, it is preferable that an electrolyte inletof the COelectrolytic laminateis positioned closer to the center in the lamination direction and in the second direction perpendicular to the first direction than an electrolyte outlet.

Further, in the embodiment, the lamination direction and the second direction perpendicular to the first direction are an upward/downward direction parallel to the paper sheet of. In, the second direction coincides with a short direction of the COelectrolytic laminate.

In the COelectrolytic laminate, in general, raw materials for at least one of the cathode and the anode are solutions, and products are gases. For this reason, in the COelectrolytic laminate, from the viewpoint of product discharge, and with the aim of utilizing gas buoyancy, the entrance for the raw materials is located below the lamination direction, and the outlet is located above the lamination direction. In addition, in the COelectrolytic laminate, chemical reactions are more likely to occur near the electrolyte inlet(a cathode inletan anode inlet) where the raw materials concentration is high, and hydrogen as a by-product is more likely to be produced near the electrolyte outlet(a cathode outletan anode outlet) where the raw materials concentration is low.

In the COelectrolysis deviceaccording to the embodiment, the highest pressure is applied to an area indicated by the two-dot chain line in. Here, as shown in, by disposing the electrolyte inletof the COelectrolytic laminatenear the center in the second direction (short direction), a higher pressure can be applied to the vicinity of the electrolyte inlet. Accordingly, a current can preferably flow near the electrolyte inlet, and the chemical reaction can be further promoted. In addition, since the pressure is lower near the electrolyte outletthan near the electrolyte inlet, the current flow is inhibited, which suppresses the generation of hydrogen that is a by-product. These effects can further increase the COrecovery efficiency of the COelectrolysis device.

In addition, as shown in, the COelectrolytic laminateis preferably disposed such that a distance of a flow path(a cathode flow pathan anode flow path) is shortened. Accordingly, for example, in comparison with the case in which the COelectrolytic laminateis disposed such that the flow pathis disposed in the leftward/rightward direction (the longitudinal direction of the COelectrolytic laminate) parallel to the drawing of, pressure loss in the end portions in the longitudinal direction can be suppressed, and COrecovery efficiency can be further improved.

While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.