Electrolytic bath

Abstract

An electrolytic cell capable of ensuring stable operation of the electrolytic cell while avoiding an increase in electrolytic voltage is provided with: a cathode housing to which a cathode plate is fixed on the inner surface; an anode housing to which an anode plate is fixed on the inner surface; and an ion exchange membrane disposed between the cathode housing and the anode housing. A cathode-side fluid supply path for supplying a cathode-side fluid to a cathode chamber defined between the cathode housing and the ion exchange membrane; a cathode-side fluid discharge path for discharging the cathode-side fluid from the cathode chamber; and an anode-side fluid supply path for supplying an anode-side fluid to an anode chamber defined between the anode housing and the ion exchange membrane. And an anode-side fluid discharge path for discharging the anode-side fluid from the anode chamber. The effective flow path cross-sectional area CD of the cathode-side fluid discharge path is larger than the effective flow path cross-sectional area CS of the cathode-side fluid supply path, and the effective flow path cross-sectional area AD of the anode-side fluid discharge path is larger than the effective flow path cross-sectional area AS of the anode-side fluid supply path.

Description

Technical Field

[0001] The present invention relates to an electrolytic cell, and more particularly to an electrolytic cell suitable for producing a quaternary ammonium hydroxide aqueous solution using a quaternary ammonium salt aqueous solution as a raw material, but is not limited thereto. Background Art

[0002] The following patent documents 1 to 4 disclose a method for producing a quaternary ammonium hydroxide aqueous solution using a quaternary ammonium salt aqueous solution as a raw material. Such a manufacturing method is implemented using an electrolytic cell, which includes a cathode frame, a cathode plate fixed to the inner surface of the cathode frame, an anode frame, and an anode plate fixed to the inner surface of the anode frame. At least one cation exchange membrane is arranged between the cathode plate and the anode plate, a cathode chamber is defined between the cathode frame and the cation exchange membrane, and an anode chamber is defined between the anode frame and the cation exchange membrane. In addition, a cathode side fluid supply path for supplying a cathode side fluid to the cathode chamber and a cathode side fluid discharge path for discharging a cathode side fluid from the cathode chamber, as well as an anode side fluid supply path for supplying an anode side fluid to the anode chamber and an anode side fluid discharge path for discharging an anode side fluid from the anode chamber are arranged. In more detail, the cathode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at intervals in the width direction and a plurality of lower flow paths extending from a plurality of lower openings arranged at intervals in the width direction, one of the upper flow paths and the lower flow paths constitutes the cathode side fluid discharge path, and the other of the upper flow paths and the lower flow paths constitutes the cathode side fluid supply path. Similarly, the anode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at intervals in the width direction and a plurality of lower flow paths extending from a plurality of lower openings arranged at intervals in the width direction, one of the upper flow paths and the lower flow paths constitutes the anode side fluid discharge path, and the other of the upper flow paths and the lower flow paths constitutes the anode side fluid supply path. The cathode side fluid, i.e., the quaternary ammonium hydroxide aqueous solution, circulates via the cathode side fluid supply path, the cathode chamber, and the cathode side fluid discharge path, and the anode side fluid, i.e., the quaternary ammonium salt aqueous solution, circulates via the anode side fluid supply path, the anode chamber, and the anode side fluid discharge path.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 62-142792

[0006] Patent Document 2: Japanese Patent Publication No. 8-16274

[0007] Patent Document 3: Japanese Patent Publication No. 8-19539

[0008] Patent Document 4: Japanese Patent Application Publication No. 2009-13477 Summary of the invention

[0009] Problem that the invention aims to solve

[0010] In this way, in the electrolytic cell as described above, the effective flow cross-sectional area of ​​the cathode side fluid supply path and the effective flow cross-sectional area of ​​the cathode side fluid discharge path are set to be substantially the same, and the effective flow cross-sectional area of ​​the anode side fluid supply path and the effective flow cross-sectional area of ​​the anode side fluid discharge path are set to be substantially the same. Moreover, in particular, in the electrolytic cell of the method proposed by the inventors of the present invention in Japanese Patent Application No. 2022-33651 (i.e., an electrolytic cell of the following method: at least one upper through opening connected to the upper opening of the cathode frame is formed at the upper end of the cathode plate, at least one lower through opening connected to the lower opening of the cathode frame is formed at the lower end of the cathode plate, at least one upper through opening connected to the upper opening of the anode frame is formed at the upper end of the anode plate, at least one lower through opening connected to the lower opening of the anode frame is formed at the lower end of the anode plate, and the upper through opening and the lower through opening formed in the cathode plate, and the upper through opening and the lower through opening formed in the anode plate define the effective flow path cross-sectional area of ​​the fluid flow path), in order to achieve maximum electric field efficiency, the effective flow path area is set to the necessary minimum. However, the inventors of the present invention have repeatedly conducted intensive research and experiments on the operation of the electrolytic cell, and as a result, they have come to realize that gas is generated by electrolysis in the cathode chamber and the anode chamber, and since the generated gas also flows in the cathode side fluid discharge path and the anode side fluid discharge path in addition to the cathode side fluid and the anode side fluid, the flow rate in the cathode side fluid discharge path and the anode side fluid discharge path is increased compared to the cathode side fluid supply path and the anode side fluid supply path, thereby generating back pressure, thereby causing the electrolysis voltage to rise and hindering the stable operation of the electrolytic cell.

[0011] The present invention has been accomplished in view of the above circumstances, and a main technical object of the present invention is to provide a novel and improved electrolytic cell that avoids an increase in electrolytic voltage and ensures stable operation of the electrolytic cell.

[0012] Solutions for solving problems

[0013] Based on the above facts recognized by the inventors of the present invention, it was discovered that the above-mentioned main technical issues can be achieved by setting the effective flow cross-sectional area CD of the cathode side fluid discharge path to be larger than the effective flow cross-sectional area CS of the cathode side fluid supply path, and setting the effective flow cross-sectional area AD of the anode side fluid discharge path to be larger than the effective flow cross-sectional area AS of the anode side fluid supply path.

[0014] That is, according to the present invention, as an electrolytic cell for achieving the above-mentioned main technical problems, there is provided the following electrolytic cell:

[0015] An electrolytic cell, comprising a cathode frame having a cathode plate fixed on its inner surface, an anode frame having an anode plate fixed on its inner surface, an ion exchange membrane disposed between the cathode frame and the anode frame, a cathode side fluid supply path for supplying a cathode side fluid to a cathode chamber defined between the cathode frame and the ion exchange membrane, a cathode side fluid discharge path for discharging the cathode side fluid from the cathode chamber, an anode side fluid supply path for supplying an anode side fluid to an anode chamber defined between the anode frame and the ion exchange membrane, and an anode side fluid discharge path for discharging the anode side fluid from the anode chamber,

[0016] The electrolytic cell is characterized in that

[0017] The effective flow cross-sectional area CD of the cathode side fluid discharge path is larger than the effective flow cross-sectional area CS of the cathode side fluid supply path, and the effective flow cross-sectional area AD of the anode side fluid discharge path is larger than the effective flow cross-sectional area AS of the anode side fluid supply path.

[0018] The effective flow path cross-sectional area CD is 1.1 to 3.0 times (CD=1.1 to 3.0CS) of the effective flow path cross-sectional area CS, and the effective flow path cross-sectional area AD is 1.1 to 3.0 times (AD=1.1 to 3.0AS) of the effective flow path cross-sectional area AS. Particularly preferably, the effective flow path cross-sectional area CD is 1.5 to 2.5 times (CD=1.5 to 2.5CS) of the effective flow path cross-sectional area CS, and the effective flow path cross-sectional area AD is 1.5 to 2.5 times (AD=1.5 to 2.5AS) of the effective flow path cross-sectional area AS.

[0019] In a preferred embodiment,

[0020] The cathode frame is provided with at least one upper flow path extending from an upper opening located at an upper end of the inner surface and at least one lower flow path extending from a lower opening located at a lower end of the inner surface.

[0021] The anode frame is provided with at least one upper flow path extending from an upper opening located at an upper end of the inner surface and at least one lower flow path extending from a lower opening located at a lower end of the inner surface.

[0022] The cathode plate continuously extends from a position above the upper opening of the cathode frame to a position below the lower opening of the cathode frame.

[0023] At least one upper through opening communicating with the upper opening of the cathode frame is formed at the upper end of the cathode plate, and at least one lower through opening communicating with the lower opening of the cathode frame is formed at the lower end of the cathode plate.

[0024] The anode plate continuously extends from a position above the upper opening of the anode frame to a position below the lower opening of the anode frame.

[0025] At least one upper through opening communicating with the upper opening of the anode frame is formed at the upper end of the anode plate, and at least one lower through opening communicating with the lower opening of the anode frame is formed at the lower end of the anode plate.

[0026] The upper through opening of the cathode plate and the upper flow path of the cathode frame constitute one of the cathode side fluid discharge path and the cathode side fluid supply path, and the lower through opening of the cathode plate and the lower flow path of the cathode frame constitute the other of the cathode side fluid discharge path and the cathode side fluid supply path.

[0027] The upper through opening of the anode plate and the upper flow path of the anode frame constitute one of the anode side fluid discharge path and the anode side fluid supply path, and the lower through opening of the anode plate and the lower flow path of the anode frame constitute the other of the anode side fluid discharge path and the anode side fluid supply path.

[0028] Preferably, the cathode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at intervals in the width direction at the upper end of the inner surface, and a plurality of lower flow paths extending from a plurality of lower openings arranged at intervals in the width direction at the lower end of the inner surface.

[0029] The anode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at intervals in the width direction at the upper end of the inner surface, and a plurality of lower flow paths extending from a plurality of lower openings arranged at intervals in the width direction at the lower end of the inner surface.

[0030] A plurality of upper through openings are formed at the upper end of the cathode plate and are respectively connected to each of the plurality of upper openings of the cathode frame, and a plurality of lower through openings are formed at the lower end of the cathode plate and are respectively connected to each of the plurality of lower openings of the cathode frame.

[0031] A plurality of upper through openings are formed at the upper end of the anode plate and are respectively connected to each of the plurality of upper openings of the anode frame, and a plurality of lower through openings are formed at the lower end of the anode plate and are respectively connected to each of the plurality of lower openings of the anode frame.

[0032] The number of the upper through opening of the cathode plate and the upper flow path of the cathode frame or the lower through opening of the cathode plate and the lower flow path of the cathode frame constituting the cathode side fluid discharge path is greater than the number of the lower through opening of the cathode plate and the lower flow path of the cathode frame or the upper through opening of the cathode plate and the upper flow path of the cathode frame constituting the cathode side fluid supply path,

[0033] The number of the upper through openings of the anode plate and the upper flow path of the anode frame or the lower through openings of the anode plate and the lower flow path of the anode frame constituting the anode side fluid discharge path is greater than the number of the lower through openings of the anode plate and the lower flow path of the anode frame or the upper through openings of the anode plate and the upper flow path of the anode frame constituting the anode side fluid supply path.

[0034] Preferably, the upper opening and the lower opening of the cathode frame, and the upper through opening and the lower through opening of the cathode plate have a circular cross-sectional shape, and the upper opening and the lower opening of the anode frame, and the upper through opening and the lower through opening of the anode plate have a circular cross-sectional shape. The cathode plate and the anode plate are preferably composed of rectangular plates.

[0035] In a preferred embodiment of the present invention, in the electrolytic cell as described above, at least one cation exchange membrane is arranged between the cathode plate and the anode plate, and such an electrolytic cell is used to produce a quaternary ammonium hydroxide aqueous solution using a quaternary ammonium salt aqueous solution as a raw material.

[0036] Effects of the Invention

[0037] In the electrolytic cell of the present invention, since the effective flow cross-sectional area CD of the cathode side fluid discharge path is larger than the effective flow cross-sectional area CS of the cathode side fluid supply path, and the effective flow cross-sectional area AD of the anode side fluid discharge path is larger than the effective flow cross-sectional area AS of the anode side fluid supply path, as can be clearly understood based on the embodiments described later, the increase in electrolysis voltage can be avoided and the stable operation of the electrolytic cell can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic cross-sectional view showing a preferred embodiment of an electrolytic cell constructed according to the present invention.

[0039] Figure 2 Yes means Figure 1 The cathode frame and cathode plate in the electrolytic cell shown in FIG. Figure 1 A simplified cross-sectional view along line II-II.

[0040] Figure 3 Yes means Figure 1A partially enlarged cross-sectional view of an upper opening of a cathode frame, an upper through opening formed in a cathode plate, and an upper communicating opening formed in a gasket of an electrolytic cell is shown.

[0041] Figure 4 The cathode frame and cathode plate in a modified example of the electrolytic cell according to the present invention are shown. Figure 2 Same simplified cross-section view. DETAILED DESCRIPTION

[0042] Hereinafter, the electrolytic cell constructed according to the present invention will be described in more detail with reference to the accompanying drawings showing preferred embodiments thereof.

[0043] The following reference Figure 1 and Figure 2 The electrolytic cell shown in the figure according to the present invention comprises a cathode frame 4 ( Figure 1 )、Anode frame 6( Figure 1 )、Cathode side upper wall member 8、Anode side upper wall member 10、Cathode side lower wall member 12、Anode side lower wall member 14、Cathode side front wall member 16( Figure 2 ), anode side front wall member (not shown), cathode side rear wall member 18 ( Figure 2 ) and an anode side rear wall member (not shown) are formed into a hollow cubic shell 2. The cathode frame 4, the anode frame 6, the cathode side front wall member 16, the anode side front wall member, the cathode side rear wall member 18 and the anode side rear wall member extend substantially vertically, and the cathode side upper wall member 8, the anode side upper wall member 10, the cathode side lower wall member 12 and the anode side lower wall member 14 extend substantially horizontally. The base end surface of the cathode side upper wall member 8 (at Figure 1 The right end face in the middle) is connected to the inner surface of the cathode frame 4 by a suitable connecting member such as a fastening screw or an adhesive, and the base end face of the cathode side lower wall member 12 (at Figure 1 The right end face in the middle) is connected to the lower edge of the inner surface of the cathode frame 4 by using an appropriate connecting member. Similarly, the base end face of the anode side upper wall member 10 (at Figure 1 The left end face in the middle) is connected to the inner surface of the anode frame 6 by using appropriate connecting parts, and the base end face of the anode side lower wall member 14 (at Figure 1The cathode side front wall member 16 is connected to the front surface of the cathode frame 4 by an appropriate connecting member, the anode side front wall member is connected to the front surface of the anode frame 6 by an appropriate connecting member, the cathode side rear wall member 18 is connected to the rear surface of the cathode frame 4 by an appropriate connecting member, and the anode side rear wall member is connected to the rear surface of the anode frame 6 by an appropriate connecting member. As for the cathode side upper wall member 8 and the anode side upper wall member 10, the cathode side lower wall member 12 and the anode side lower wall member 14, and the cathode side front wall member 16 and the cathode side rear wall member 18, these wall members can also be formed integrally in advance and connected to the cathode frame 4 or the anode frame 6, instead of being connected to the cathode frame 4 or the anode frame 6 as described above. In addition, the wall portion can also be formed integrally with the cathode frame 4 or the anode frame 6. Furthermore, when the upper wall members 8 and 10, the lower wall members 12 and 14, and the front wall member 16 and the rear wall member 18 are integrally formed, they can also be fixed to the cathode frame 4 or the anode frame 6 via the sealing member. As the sealing member, the gasket 38 described later can also be extended from the size corresponding to the cathode plate 32 or the anode plate 56 to the size corresponding to the cathode frame 4 or the anode frame 6 by using the extension portion. The cathode frame 4, the anode frame 6, the cathode side upper wall member 8, the anode side upper wall member 10, the cathode side lower wall member 12, the anode side lower wall member 14, the cathode side front wall member 16, the anode side front wall member, the cathode side rear wall member 18 and the anode side rear wall member can be in the form of a solid block or plate, except for the opening and flow path described later, and can be formed of an olefin resin such as polypropylene and polyethylene, a vinyl chloride resin, and an appropriate synthetic resin such as a fluororesin. Appropriate sealing members (not shown) such as gaskets are sandwiched between the cathode frame 4, the anode frame 6, the cathode side upper wall member 8, the anode side upper wall member 10, the cathode side lower wall member 12, the anode side lower wall member 14, the cathode side front wall member 16, the anode side front wall member, the cathode side rear wall member 18 and the mutually connected parts of the anode side rear wall member.

[0044] The following reference Figure 1 , Figure 2 as well as Figure 3 Continuing the description, on the inner surface of the cathode frame 4 (at Figure 1 The upper end portion of the left side in the middle) is along the width direction (in Figure 1 is the direction perpendicular to the paper surface, Figure 2 A plurality of upper openings 20 (six in the case shown) are formed at equal intervals (in the left and right directions) Figure 1 and Figure 3In the figure, one of them is shown by a dotted line and a solid line respectively), and the cathode frame 4 is formed with a plurality of (six in the case of the figure) upper flow paths 22 (in the figure) extending substantially horizontally from each upper opening 20 through the cathode frame 4. Figure 1 and Figure 3 In the figure, one of them is shown by a dotted line and a solid line respectively). Similarly, on the inner surface of the cathode frame 4 (at Figure 1 The lower end portion of the left side in the width direction (in Figure 1 is the direction perpendicular to the paper surface, Figure 2 A plurality of lower openings 24 (in the left and right directions) are formed at equal intervals (three in the case of the figure) (in the left and right directions). Figure 1 In the figure, one of them is shown by a dotted line), and the cathode frame 4 is formed with a plurality of (three in the case of the figure) lower flow paths 26 (in the figure) extending substantially horizontally from each lower opening 24 through the cathode frame 4. Figure 1 In the figure, one of them is shown by a dotted line. The upper opening 20 and the lower opening 24 may be circular, and the cross-sectional shape of the upper flow path 22 and the cross-sectional shape of the lower flow path 26 may be circular in accordance with the circular shape of the upper opening 20 and the lower opening 24. The upstream flow path 22 and the downstream flow path 26 are connected by an outer flow path (not shown) provided on the outer side of the housing 2. Figure 2 The outer flow path and the structural elements as described above arranged in the outer flow path are well known to those skilled in the art, and therefore their detailed description is omitted in this specification.

[0045] A cathode plate 32 is fixed to the inner surface of the cathode frame 4. In the illustrated embodiment, the cathode plate 32 extends continuously from a position above the upper opening 20 formed in the cathode frame 4 to a position below the lower opening 24 formed in the cathode frame 4. The cathode plate 32 is composed of a rectangular plate formed of a suitable conductive metal such as nickel, the upper end surface of the cathode plate 32 abuts or approaches the inner surface (i.e., the lower surface) of the cathode side upper wall member 8, the lower end surface of the cathode plate 32 abuts or approaches the inner surface (i.e., the upper surface) of the cathode side lower wall member 12, the front side surface of the cathode plate 32 abuts or approaches the inner surface (i.e., the rear surface) of the front wall member 16, and the rear side surface of the cathode plate 32 abuts or approaches the inner surface (i.e., the front surface) of the rear wall member 18. The cathode plate 32 can be fixed to the cathode frame 4 by, for example, passing fastening screws (not shown) through the four corners of the cathode plate 32 and threading them into the cathode frame 4. Figure 1 In the direction perpendicular to the paper, Figure 2A plurality of (six in the case shown) upper through openings 34 are formed at equal intervals at the lower end of the cathode plate 32 in the width direction (in the left-right direction). Figure 1 In the direction perpendicular to the paper, Figure 2 A plurality of (three in the case of the figure) lower through openings 36 are formed at equal intervals (in the left-right direction) apart from each other (see below for the upper through openings 34 and the lower through openings 36). Each of the upper through openings 34 formed on the cathode plate 32 is located at a position that is respectively connected to each of the above-mentioned upper openings 20 formed at the upper end of the cathode frame 4. In the illustrated embodiment, each of the upper through openings 34 is the same shape (thus circular) and the same size as each of the above-mentioned upper openings 20. It is also important that each of the lower through openings 36 formed on the cathode plate 32 is located at a position that is respectively connected to each of the above-mentioned lower openings 24 formed at the lower end of the cathode frame 4. In the illustrated embodiment, each of the lower through openings 36 is the same shape (thus circular) and the same size as each of the above-mentioned lower openings 24. The upper through opening 34 (and the upper opening 20 ) is preferably located near the upper end of the cathode plate 32 , and the lower through opening 36 (and the lower opening 24 ) is preferably located near the lower end of the cathode plate 32 .

[0046] The following reference Figure 1 and Figure 3 Continuing to explain, preferably between the cathode frame 4 and the cathode plate 32, a gasket 38 is sandwiched. The cathode plate 32 can be stably fixed to the cathode frame 4 by the gasket 38, and corrosion caused by the penetration of liquid into the interface of the cathode frame 4 and the cathode plate 32 can be prevented. The gasket 38 can be a rectangular plate of substantially the same size as the cathode plate 32 (as mentioned above, the gasket 38 can also be set to a size corresponding to the cathode frame 4), and can be formed by a suitable elastomer, such as silicone rubber, ethylene propylene rubber, chloroprene rubber, soft vinyl chloride, butyl rubber, butadiene rubber or fluororubber. When the gasket 38 is sandwiched between the cathode frame 4 and the cathode plate 32, a fastening screw (not shown) can be threadedly connected to the cathode frame 4 by passing through the cathode plate 32 and the gasket 38 at the four corners of the cathode plate 32. A plurality of (six in the illustrated case) upper communicating openings 40 are formed at the upper end of the gasket 38 to communicate each of the upper through openings 34 formed in the cathode plate 32 with each of the upper openings 20 formed in the cathode frame 4, and a plurality of (three in the illustrated case) lower communicating openings 42 are formed at the lower end of the gasket 38 to communicate each of the lower through openings 36 formed in the cathode plate 32 with each of the lower openings 24 formed in the cathode frame 4. Figure 3As can be clearly understood, the upper communication opening 40 and the lower communication opening 42 formed in the gasket 38 are preferably larger than the upper through-opening 34 and the upper opening 20, and the lower through-opening 36 and the lower opening 24. When the upper communication opening 40 and the lower communication opening 42 formed in the gasket 38 are substantially the same size as the upper through-opening 34 and the upper opening 20, and the lower through-opening 36 and the lower opening 24, if the electrolytic cell is continuously operated, the gasket 38 expands slightly, and the upper communication opening 40 and the lower communication opening 42 shrink and shift, thereby causing the communication between the upper through-opening 34 and the upper opening 20, and the communication between the lower through-opening 36 and the lower opening 24 to be insufficient or damaged. The upper communication opening 40 and the lower communication opening 42 may be circular with a diameter larger than the diameter of the upper through-opening 34 and the upper opening 20, and the lower through-opening 36 and the lower opening 24 by a predetermined length. The upper communication opening 40 and the lower communication opening 42 do not need to be concentric with the upper through opening 34 and the upper opening 20 and the lower through opening 36 and the lower opening 24, respectively, and can be eccentric. The diameters of the upper communication opening 40 and the lower communication opening 42 and the degree of eccentricity relative to the upper through opening 34 and the upper opening 20 and the lower through opening 36 and the lower opening 24 can be experimentally set based on the expansion and displacement of the gasket 38 caused by the continuous operation of the electrolytic cell. The larger the upper communication opening 40 and the lower communication opening 42 formed in the gasket 38, the lower the possibility of insufficient connection or damage, but as described later, the area of ​​contact between the liquid and the back of the cathode plate 32 increases, thereby causing electrocorrosion or corrosion, and the electrode metal mixed in the liquid increases. Therefore, the preferred dimensions of the upper connecting opening 40 and the lower connecting opening 42 formed in the gasket 38 are the dimensions of the upper through-opening 34 and the upper opening 20 and the lower through-opening 36 and the lower opening 24 + 30 mm or less, preferably + 20 mm or less, and more preferably + 10 mm or less. In addition, if the gasket 38 is made of a material that is not easy to expand, even if the dimensions of the upper connecting opening 40 and the lower connecting opening 42 are close to the dimensions of the upper through-opening 34 and the upper opening 20 and the lower through-opening 36 and the lower opening 24, the possibility of insufficient connection or damage will be reduced. Therefore, as the material used for the gasket 38, the linear expansion coefficient is preferably 3×10 -4 (1 / °C) or less, more preferably 1.5×10 -4 (1 / °C) or less, and most preferably 1×10 -4 (1 / ℃) or less.

[0047] In the illustrated embodiment, the anode frame 6 is substantially the same as the cathode frame 4 described above. More specifically, a gap is formed between the cathode frame 4 and the anode frame 6. Figure 1The imaginary plane extending perpendicularly to the paper surface is symmetrical in the plane of symmetry. Therefore, the anode frame 6 is provided with an upper opening 44, an upper flow path 46, a lower opening 48 and a lower flow path 50. In order to avoid repeated description, the detailed description of the upper opening 44, the upper flow path 46, the lower opening 48 and the lower flow path 50 is omitted. The upper flow path 46 and the lower flow path 50 are connected by an outer flow path (not shown) arranged on the outer side of the shell 2, and a circulation pump, a raw material storage tank and a plurality of valve components for flow control are also provided in the outer flow path (the outer flow path and the structural elements as described above arranged on the outer flow path are well known to those skilled in the art, so the detailed description thereof is omitted in this specification).

[0048] An anode plate 56 is fixed to the inner surface of the anode frame 6. In the illustrated embodiment, the anode plate 56 is substantially the same as the above-mentioned cathode plate 32 except that it is formed of a suitable conductive metal suitable for the anode, for example, titanium plated with indium oxide on the surface. More specifically, a gap is formed between the cathode plate 32 and the anode plate 56. Figure 1 The anode plate 56 is symmetrical with respect to the imaginary plane extending perpendicularly to the paper surface as the symmetric plane. Therefore, the anode plate 56 is a rectangular shape that continuously extends from a position above the upper opening 44 formed in the anode frame 6 to a position below the lower opening 48 formed in the anode frame 6. In addition, the anode plate 56 is formed with an upper through opening 58 and a lower through opening 60 located at positions that are respectively connected to the upper opening 44 and the lower opening 48 formed in the anode frame 6. In order to avoid repeated description, the detailed description of the anode plate 56 is omitted.

[0049] In the illustrated embodiment, a gasket 62 is also interposed between the anode frame 6 and the anode plate 56. The gasket 62 is also substantially the same as the gasket 38 interposed between the cathode frame 4 and the cathode plate 32. More specifically, a gasket 38 and a gasket 62 are formed between the two. Figure 1 Therefore, the gasket 62 is formed with an upper communication opening 64 that connects the upper opening 44 formed in the anode frame 6 with the upper through opening 58 formed in the anode plate 56, and a lower communication opening 66 that connects the lower opening 48 formed in the anode frame 6 with the lower through opening 60 formed in the anode plate 56. In order to avoid repeated description, detailed description of the gasket 62, the upper communication opening 64, and the lower communication opening 66 is omitted.

[0050] As reference Figure 1As can be clearly understood, in the illustrated embodiment, a cation exchange membrane 68 is provided between the cathode plate 32 and the anode plate 56. The cation exchange membrane 68, which can be a known form, is in the shape of a rectangular plate, and its upper end edge is held between the cathode side upper wall member 8 and the anode side upper wall member 10, and its lower end edge is held between the cathode side lower wall member 12 and the anode side lower wall member 14, and the front surface side edge of the cathode frame 4 and the anode frame 6 is held between the cathode side front wall member 16 and the anode side front wall member, and the rear surface side edge of the cathode frame 4 and the anode frame 6 is held between the cathode side rear wall member 18 and the anode side rear wall member. Appropriate sealing components (not shown) can be clamped between the cation exchange membrane 68 and the cathode side upper wall component 8 and the anode side upper wall component 10, between the cation exchange membrane 68 and the cathode side lower wall component 12 and the anode side lower wall component 14, between the cation exchange membrane 68 and the cathode side front wall component 16 and the anode side front wall component, and between the cation exchange membrane 68 and the cathode side rear wall component 18 and the anode side rear wall component.

[0051] In the electrolytic cell as described above, a cathode chamber or a product chamber 70 is defined between the cathode plate 32 and the cation exchange membrane 68, and an anode chamber, i.e., a raw material chamber 72, is defined between the anode plate 56 and the cation exchange membrane 68. Moreover, the initially diluted quaternary ammonium hydroxide aqueous solution (or pure water) circulates via the product chamber 70, more specifically, flows into the product chamber 70 via one of the lower flow path 26 and the upper flow path 22 formed in the cathode frame 4, and flows out from the product chamber 70 via the other. Meanwhile, the quaternary ammonium salt aqueous solution circulates via the raw material chamber 72, more specifically, flows into the raw material chamber 72 via one of the lower flow path 50 and the upper flow path 46 formed in the anode frame 6, and flows out via the other. An electrolysis voltage is applied between the cathode plate 32 and the anode plate 56. In this way, the concentration of the quaternary ammonium hydroxide aqueous solution circulating in the product chamber 70 gradually increases. Such electrolysis is well known to those skilled in the art, and therefore its detailed description is omitted in this specification. Thus, in the illustrated embodiment of the electrolytic cell according to the present invention, the cathode plate 32 is in the form of continuously extending from a position above the upper opening 20 formed in the cathode frame 4 to a position below the lower opening 24 formed in the cathode frame 4, and the anode plate 56 is in the form of continuously extending from a position above the upper opening 44 formed in the anode frame 6 to a position below the lower opening 48 formed in the anode frame 6, and a portion of the cathode plate 32 is formed with the upper opening 20 and the lower opening 24 formed in the cathode frame 4. An upper through opening 34 and a lower through opening 36 connected to the lower opening 24 are formed on the anode plate 56, and an upper through opening 58 and a lower through opening 60 connected to the upper opening 44 and the lower opening 48 are formed. Therefore, the cathode plate 32 and the anode plate 56 extend substantially entirely across the inner surfaces of the cathode frame 4 and the anode frame 6, respectively. Therefore, the relative current-carrying area of ​​the cathode plate 32 and the anode plate 56 is larger than the size of the electrolytic cell, and electrolysis is carried out by utilizing the improved electrolysis efficiency.

[0052] In the electrolytic cell constructed according to the present invention, it is important that the effective flow path cross-sectional area CD of the cathode side fluid discharge path is larger than the effective flow path cross-sectional area CS of the cathode side fluid supply path, and similarly, the effective flow path cross-sectional area AD of the anode side fluid discharge path is larger than the effective flow path cross-sectional area AS of the anode side fluid supply path. The term "effective flow path cross-sectional area" means the minimum cross-sectional area in the flow path. In the illustrated embodiment, the cathode side fluid discharge path CD is defined by the six upper through openings 34 formed in the cathode plate 32, the upper communication openings 40 continuous with the upper through openings 34, the upper openings 20, the upper flow path 22, and a portion of the outer flow path 31. The cross-sectional areas of the upper communication openings 34, the upper openings 20, the upper flow path 22, and a portion of the outer flow path 31 are the same as or larger than the cross-sectional area of ​​the upper through openings 34. Therefore, the effective flow path cross-sectional area CD of the cathode side fluid discharge path is defined by the total cross-sectional area of ​​the six upper through openings 34. In addition, the effective flow path cross-sectional area CS of the cathode side fluid supply path is defined by the three lower through openings 36 formed in the cathode plate 32, the lower communication openings 42 continuous with the lower through openings 36, the lower openings 24, the lower flow path 26, and a portion of the outer flow path 31. The cross-sectional areas of the lower communication openings 42, the lower openings 24, the lower flow path 26, and a portion of the outer flow path 31 are equal to or larger than the cross-sectional area of ​​the lower through openings 36. Therefore, the effective flow path cross-sectional area CD of the cathode side fluid discharge path is defined by the total cross-sectional area of ​​the three lower through openings 36. In particular, from the viewpoint of suppressing the increase in back pressure caused by the discharged fluid, the cross-sectional area of ​​a portion of the outer flow path 31 is preferably larger than the cross-sectional area of ​​the upper through opening 34 or the lower through opening 36. Specifically, the cross-sectional area of ​​a portion of the outer flow path 31 is preferably 1.0 times or more, and more preferably 1.5 times or more, the cross-sectional area of ​​the upper through opening 34 or the lower through opening 36. The cross-sectional area of ​​a portion of the outer flow path 31 with respect to the upper through-opening 34 or the lower through-opening 36 is appropriately determined in consideration of the effective flow path cross-sectional area and the supply amount of the fluid.

[0053] In the illustrated embodiment, as described above, the upper through opening 34 is Figure 1 is the direction perpendicular to the paper surface, Figure 2 In the left-right direction, six openings are formed at equal intervals in the upper and lower sides. In contrast, the lower through openings 36 are arranged in the width direction (in the left-right direction). Figure 1 is the direction perpendicular to the paper surface, Figure 2Three of the six upper through openings 34 are formed at equal intervals on the cathode side (in the left-right direction), and the cross-sectional area of ​​each of the six upper through openings 34 is the same as the cross-sectional area of ​​each of the three lower through openings 36. Therefore, the effective flow path cross-sectional area CD of the cathode side fluid discharge path is twice the effective flow path cross-sectional area CS of the cathode side fluid supply path. As can be understood from the embodiments described later, the effective flow path cross-sectional area CD of the cathode side fluid discharge path is 1.1 to 3.0 times (CD = 1.1 to 3.0 CS) of the effective flow path cross-sectional area CS of the cathode side fluid supply path, and is particularly preferably 1.5 to 2.5 times (CD = 1.5 to 2.5 CS).

[0054] In order to achieve the maximum electric field efficiency, the cross-sectional area of ​​the upper through opening 34 and the lower through opening 36 formed in the cathode plate 32 is preferably set to the minimum necessary limit. However, the inventors of the present invention have repeatedly conducted intensive research and experiments on the operation of the electrolytic cell, and as a result, gas is generated in the cathode chamber or the product chamber 70 due to electrolysis, and in addition to the cathode side fluid, the generated gas also flows in the cathode side fluid discharge path. Therefore, if the effective flow path cross-sectional area CD of the cathode side fluid discharge path is set to be the same as the effective flow path cross-sectional area CS of the cathode side fluid supply path, the flow rate in the cathode side fluid discharge path increases compared to the cathode side fluid supply path, generating back pressure, thereby there is a tendency that the electrolysis voltage rises and the stable operation of the electrolytic cell is hindered. However, in the electrolytic cell constructed according to the present invention, since the effective flow path cross-sectional area CD of the cathode side fluid discharge path is set to be larger than the effective flow path cross-sectional area CS of the cathode side fluid supply path, the rise of the electrolysis voltage can be avoided and the stable operation of the electrolytic cell can be ensured, as can be clearly understood from the embodiments described later.

[0055] exist Figure 1 to Figure 3 In the above-described embodiment shown in , the number of upper through openings 34 (6) is set to be greater than the number of lower through openings 36 (3), and the effective flow path cross-sectional area CD of the cathode side fluid discharge path is set to be larger than the effective flow path cross-sectional area CS of the cathode side fluid supply path. However, if desired, the number of upper through openings 34 and the number of lower through openings 36 can be set to be the same, the cross-sectional area of ​​each upper through opening 34 can be set to be larger than the cross-sectional area of ​​each lower through opening 36, and the effective flow path cross-sectional area CD of the cathode side fluid discharge path can be set to be larger than the effective flow path cross-sectional area CS of the cathode side fluid supply path. Figure 4 In the modified example shown, the upper end of the cathode plate 32 is Figure 4 The cathode plate 32 has three upper through openings 34 spaced at equal intervals (therefore, the upper communicating opening 40, the upper opening 20, and the upper flow path 22 are also formed with three each), and the cathode plate 32 has three upper through openings 34 spaced at equal intervals (therefore, the upper communicating opening 40, the upper opening 20, and the upper flow path 22 are also formed with three each). Figure 4Three lower through openings 36 are formed at equal intervals (in the left-right direction), and the cross-sectional area of ​​each upper through opening 34 is set to be twice the cross-sectional area of ​​each lower through opening 36. However, according to the experience of the inventors of the present invention, compared with setting the cross-sectional area of ​​each upper through opening 34 larger than the cross-sectional area of ​​each lower through opening 36, setting the number of upper through openings 34 to be greater than the number of lower through openings 36 tends to make the discharge flow smoother.

[0056] In the above-mentioned embodiments and variations, a plurality of upper through openings 34 and lower through openings 36 are formed at equal intervals in the width direction on the cathode plate 32. However, if desired, an upper through opening and a lower through opening extending slenderly in the width direction can be formed on the cathode plate 32, and the cross-sectional area of ​​the upper through opening 34 is set to be larger than the cross-sectional area of ​​the lower through opening 36.

[0057] Furthermore, in the above-mentioned embodiment and modification, the cathode plate 32 is in a form that continuously extends from a position above the upper opening 20 formed in the cathode frame 4 to a position below the lower opening 24 formed in the cathode frame 4, and the upper end of the cathode plate 32 is provided with a plurality of holes in the width direction (in the middle of the cathode plate 32). Figure 1 is the direction perpendicular to the paper surface, Figure 2 and Figure 4 A plurality of upper through openings 34 are formed at equal intervals in the width direction (in the left and right direction) at the lower end of the cathode plate 32. Figure 1 is the direction perpendicular to the paper surface, Figure 2 and Figure 4 In the cathode plate 32, a plurality of lower through openings 36 are formed at equal intervals (in the left and right directions), but if desired, for example, the cathode plate 32 can be set to extend from a position lower than the upper opening 20 formed in the cathode frame 4 to a position higher than the lower opening 24 formed in the cathode frame 4, and the upper through opening 34 and the lower through opening 36 are not formed in the cathode plate 32, but the upstream end of the cathode side fluid discharge path is defined by the upper opening 20 formed in the cathode frame 4, and the downstream side of the cathode side fluid supply path is defined by the lower opening 24 formed in the cathode frame 4. In this case, the effective flow path cross-sectional area of ​​the cathode side fluid discharge path is defined by the total cross-sectional area of ​​the upper opening 20, and the effective flow path cross-sectional area of ​​the cathode side fluid supply path is defined by the total cross-sectional area of ​​the lower opening 24.

[0058] The above specifically describes the relationship between the effective flow path cross-sectional area CD of the cathode side fluid discharge path and the effective flow path cross-sectional area CS of the cathode side fluid supply path, and the relationship between the effective flow path cross-sectional area AD of the anode side fluid discharge path and the effective flow path cross-sectional area AS of the anode side fluid supply path is exactly the same. In order to avoid repeated description, the specific description of the relationship between the effective flow path cross-sectional area AD of the anode side fluid discharge path and the effective flow path cross-sectional area AS of the anode side fluid supply path is omitted.

[0059] Examples 1 to 3 and Comparative Example 1

[0060] Make as Figure 1 to Figure 3 or Figure 4 The electrolytic cell of the form shown is operated in a constant current control mode, and the average value of the battery voltage (the voltage between the anode plate and the cathode plate) during the operating time is detected. In Examples 1 to 3, the effective flow path cross-sectional area CD of the cathode side fluid discharge path is larger than the effective flow path cross-sectional area CS of the cathode side fluid supply path. Similarly, the effective flow path cross-sectional area AD of the anode side fluid discharge path is larger than the effective flow path cross-sectional area AS of the anode side fluid supply path. On the other hand, in Comparative Example 1, the effective flow path cross-sectional area CD of the cathode side fluid discharge path is the same as the effective flow path cross-sectional area CS of the cathode side fluid supply path. Similarly, the effective flow path cross-sectional area AD of the anode side fluid discharge path is the same as the effective flow path cross-sectional area AS of the anode side fluid supply path. The average value of the battery voltage is shown in Table 1.

[0061] The details of the structural elements of the electrolytic cell and its working state are as follows.

[0062] Working time: 30 days

[0063] Cathode: Nickel plate (thickness 2mm, surface size 1m×1m)

[0064] Anode: Titanium plate with indium oxide on the surface (thickness 2mm, surface size 1m×1m)

[0065] Cation exchange membrane: a membrane sold by the Chemours Company under the product name "N324" (thickness 1 mm)

[0066] Gasket: EPDM (the diameter of the upper connecting opening and the lower connecting opening is 2 mm larger than the diameter of the corresponding upper through-opening and the lower through-opening respectively)

[0067] Raw material (anode side fluid): methylammonium chloride aqueous solution

[0068] Product (cathode side fluid): methylammonium hydroxide aqueous solution

[0069] Current: 1000A (10A / dm 2 )

[0070] Working temperature: 70℃

[0071] Electrolyzer assembly temperature: 20°C

[0072] Raw material (anode side fluid) flow rate: 20L / min

[0073] Product (cathode side fluid) flow rate: 20L / min

[0074] [Table 1]

[0075]

[0076] The preferred embodiment of the present invention is described in detail with reference to the accompanying drawings, but the present invention is not limited to such an embodiment, and various deformations or modifications can be made without departing from the technical scope of the present invention, which is self-evident. For example, in the illustrated embodiment, a cation exchange membrane 68 is provided between the cathode plate 32 and the anode plate 56, but the present invention can also be applied to an electrolytic cell in which a plurality of exchange membranes (cation exchange membranes and anion exchange membranes) are provided between the cathode plate 32 and the anode plate 56.

[0077] Description of Reference Numerals

[0078] 2. Shell of electrolytic cell; 4. Cathode frame; 6. Anode frame; 8. Cathode upper wall member; 10. Anode upper wall member; 12. Cathode lower wall member; 14. Anode lower wall member; 16. Cathode front wall member; 18. Cathode rear wall member; 20. Upper opening; 22. Upper flow path; 24. Lower opening; 26. Lower flow path; 31. Outer flow path; 32. Cathode plate; 34. Upper through opening; 36. Lower Through opening; 38, gasket; 40, upper connecting opening; 42, lower connecting opening; 44, upper opening; 46, upper flow path; 48, lower opening; 50, lower flow path; 56, anode plate; 58, upper through opening; 60, lower through opening; 62, gasket; 64, upper connecting opening; 66, lower connecting opening; 68, cation exchange membrane; 70, product chamber (cathode chamber); 72, raw material chamber (anode chamber).

Claims

1. An electrolytic cell, comprising a cathode frame having a cathode plate fixed on its inner surface, an anode frame having an anode plate fixed on its inner surface, an ion exchange membrane disposed between the cathode frame and the anode frame, a cathode side fluid supply path for supplying a cathode side fluid to a cathode chamber defined between the cathode frame and the ion exchange membrane, a cathode side fluid discharge path for discharging the cathode side fluid from the cathode chamber, an anode side fluid supply path for supplying an anode side fluid to an anode chamber defined between the anode frame and the ion exchange membrane, and an anode side fluid discharge path for discharging the anode side fluid from the anode chamber, The electrolytic cell is characterized in that The effective flow cross-sectional area CD of the cathode side fluid discharge path is larger than the effective flow cross-sectional area CS of the cathode side fluid supply path, and the effective flow cross-sectional area AD of the anode side fluid discharge path is larger than the effective flow cross-sectional area AS of the anode side fluid supply path.

2. The electrolytic cell according to claim 1, wherein The effective flow path cross-sectional area CD is 1.1 to 3.0 times the effective flow path cross-sectional area CS, that is, CD=1.1 to 3.0CS, and the effective flow path cross-sectional area AD is 1.1 to 3.0 times the effective flow path cross-sectional area AS, that is, AD=1.1 to 3.0AS.

3. The electrolytic cell according to claim 2, wherein: The effective flow path cross-sectional area CD is 1.5 to 2.5 times the effective flow path cross-sectional area CS, that is, CD=1.5 to 2.5CS, and the effective flow path cross-sectional area AD is 1.5 to 2.5 times the effective flow path cross-sectional area AS, that is, AD=1.5 to 2.5AS.

4. The electrolytic cell according to any one of claims 1 to 3, wherein The cathode frame is provided with at least one upper flow path extending from an upper opening located at an upper end of the inner surface and at least one lower flow path extending from a lower opening located at a lower end of the inner surface. The anode frame is provided with at least one upper flow path extending from an upper opening located at an upper end of the inner surface and at least one lower flow path extending from a lower opening located at a lower end of the inner surface. The cathode plate continuously extends from a position above the upper opening of the cathode frame to a position below the lower opening of the cathode frame. At least one upper through opening communicating with the upper opening of the cathode frame is formed at the upper end of the cathode plate, and at least one lower through opening communicating with the lower opening of the cathode frame is formed at the lower end of the cathode plate. The anode plate continuously extends from a position above the upper opening of the anode frame to a position below the lower opening of the anode frame. At least one upper through opening communicating with the upper opening of the anode frame is formed at the upper end of the anode plate, and at least one lower through opening communicating with the lower opening of the anode frame is formed at the lower end of the anode plate. The upper through opening of the cathode plate and the upper flow path of the cathode frame constitute one of the cathode side fluid discharge path and the cathode side fluid supply path, and the lower through opening of the cathode plate and the lower flow path of the cathode frame constitute the other of the cathode side fluid discharge path and the cathode side fluid supply path. The upper through opening of the anode plate and the upper flow path of the anode frame constitute one of the anode side fluid discharge path and the anode side fluid supply path, and the lower through opening of the anode plate and the lower flow path of the anode frame constitute the other of the anode side fluid discharge path and the anode side fluid supply path.

5. The electrolytic cell according to claim 4, wherein The cathode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at intervals in the width direction at the upper end of the inner surface, and a plurality of lower flow paths extending from a plurality of lower openings arranged at intervals in the width direction at the lower end of the inner surface. The anode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at intervals in the width direction at the upper end of the inner surface, and a plurality of lower flow paths extending from a plurality of lower openings arranged at intervals in the width direction at the lower end of the inner surface. A plurality of upper through openings are formed at the upper end of the cathode plate and are respectively connected to each of the plurality of upper openings of the cathode frame, and a plurality of lower through openings are formed at the lower end of the cathode plate and are respectively connected to each of the plurality of lower openings of the cathode frame. A plurality of upper through openings are formed at the upper end of the anode plate and are respectively connected to each of the plurality of upper openings of the anode frame, and a plurality of lower through openings are formed at the lower end of the anode plate and are respectively connected to each of the plurality of lower openings of the anode frame. The number of the upper through opening of the cathode plate and the upper flow path of the cathode frame or the lower through opening of the cathode plate and the lower flow path of the cathode frame constituting the cathode side fluid discharge path is greater than the number of the lower through opening of the cathode plate and the lower flow path of the cathode frame or the upper through opening of the cathode plate and the upper flow path of the cathode frame constituting the cathode side fluid supply path, The number of the upper through openings of the anode plate and the upper flow path of the anode frame or the lower through openings of the anode plate and the lower flow path of the anode frame constituting the anode side fluid discharge path is greater than the number of the lower through openings of the anode plate and the lower flow path of the anode frame or the upper through openings of the anode plate and the upper flow path of the anode frame constituting the anode side fluid supply path.

6. The electrolytic cell according to claim 5, wherein: The upper opening and the lower opening of the cathode frame, and the upper through opening and the lower through opening of the cathode plate have a circular cross-sectional shape, The upper opening and the lower opening of the anode frame, and the upper through-opening and the lower through-opening of the anode plate have circular cross-sectional shapes.

7. The electrolytic cell according to claim 4, wherein: The cathode plate and the anode plate are composed of rectangular plates.

8. A method for producing an aqueous solution of quaternary ammonium hydroxide, wherein: The method uses the electrolytic cell according to any one of claims 1 to 3, wherein at least one cation exchange membrane is disposed between the cathode plate and the anode plate, and produces a quaternary ammonium hydroxide aqueous solution using a quaternary ammonium salt aqueous solution as a raw material.

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