Electrolytic cell

Abstract

To provide an electrolyzer that avoids electrolytic voltage rise and ensures stable electrolyzer operation.SOLUTION: An electrolyzer includes a cathode frame body with a cathode plate fixed on the inner surface, an anode frame body with an anode plate fixed on the inner surface, an ion-exchange membrane located between the cathode frame body and the anode frame body, a cathode side fluid supply passage for supplying cathode side fluid to a cathode chamber defined between the cathode frame body and the ion-exchange membrane, a cathode side fluid discharge passage for discharging cathode side fluid from the cathode chamber, an anode side fluid supply passage for supplying anode side fluid to an anode chamber defined between the anode frame body and the ion-exchange membrane, and an anode side fluid discharge passage for discharging the anode side fluid from the anode chamber. An effective flow passage cross-sectional area CD of the cathode side fluid discharge passage is larger than an effective channel cross-sectional area CS of the cathode side fluid supply flow passage, and an effective flow passage cross-sectional area AD of the anode side fluid discharge passage is larger than an effective flow passage cross-sectional area AS of the anode side fluid supply passage.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electrolytic cell, and more particularly, but not exclusively, to an electrolytic cell that can be suitably used for producing an aqueous solution of quaternary ammonium hydroxide using an aqueous solution of a quaternary ammonium salt as a raw material. [Background technology]

[0002] The following Patent Documents 1 to 4 disclose methods for producing a quaternary ammonium hydroxide aqueous solution using a quaternary ammonium salt aqueous solution as a raw material. To carry out such a production method, an electrolytic cell is used that 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 disposed 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. A cathode side fluid supply passage for supplying a cathode side fluid to the cathode chamber, a cathode side fluid discharge passage for discharging the cathode side fluid from the cathode chamber, an anode side fluid supply passage for supplying an anode side fluid to the anode chamber, and an anode side fluid discharge passage for discharging the anode side fluid from the anode chamber are provided. YangThe cathode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings spaced apart in the width direction and a plurality of lower flow paths extending from a plurality of lower openings spaced apart in the width direction, one of the upper flow paths and the lower flow paths configuring the cathode side fluid discharge path and the other of the upper flow paths and the lower flow paths configuring 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 spaced apart in the width direction and a plurality of lower flow paths extending from a plurality of lower openings spaced apart in the width direction, one of the upper flow paths and the lower flow paths configuring the anode side fluid discharge path and the other of the upper flow paths and the lower flow paths configuring the anode side fluid supply path. A cathode side fluid, i.e., a quaternary ammonium hydroxide aqueous solution, is circulated through the cathode side fluid supply channel, the cathode chamber, and the cathode side fluid discharge channel, and an anode side fluid, i.e., a quaternary ammonium salt aqueous solution, is circulated through the anode side fluid supply channel, the anode chamber, and the anode side fluid discharge channel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 62-142792 [Patent Document 2] Special Publication No. 8-16274 [Patent Document 3] Special Publication No. 8-19539 [Patent Document 4] JP 2009-13477 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the electrolytic cell as described above, the effective flow path cross-sectional area of ​​the cathode side fluid supply path and the effective flow path cross-sectional area of ​​the cathode side fluid discharge path are set to be substantially the same, and the effective flow path cross-sectional area of ​​the anode side fluid supply path and the effective flow path cross-sectional area of ​​the anode side fluid discharge path are set to be substantially the same. In particular, in an electrolytic cell of the configuration proposed by the present inventors in Patent Application No. 2022-33651 (i.e., an electrolytic cell in which the upper end of the cathode plate has at least one upper through opening formed therein that aligns with the upper opening of the cathode frame, the lower end of the cathode plate has at least one lower through opening formed therein that aligns with the lower opening of the cathode frame, the upper end of the anode plate has at least one upper through opening formed therein that aligns with the upper opening of the anode frame, and the lower end of the anode plate has at least one lower through opening formed therein that aligns with the lower opening of the anode frame, and the upper and lower through openings formed in the cathode plate and the upper and lower through openings formed in the anode plate define the effective flow path cross-sectional area of ​​the fluid flow path), the effective flow path area is set to the minimum necessary to achieve maximum electric field efficiency. However, as a result of extensive investigation and experimentation into the operation of the electrolytic cell, the inventors have recognized that gas is generated in the cathode chamber and the anode chamber due to electrolytic action, and that in addition to the cathode side fluid and the anode side fluid, the generated gas also flows in the cathode side fluid discharge channel and the anode side fluid discharge channel, resulting in an increased flow rate in the cathode side fluid discharge channel and the anode side fluid discharge channel compared to the cathode side fluid supply channel and the anode side fluid supply channel, generating back pressure, which tends to increase the electrolytic voltage and hinder stable operation of the electrolytic cell.

[0005] The present invention has been made in view of the above-mentioned circumstances, and its main technical object is to provide a new and improved electrolytic cell in which an increase in electrolysis voltage is avoided and stable operation of the electrolytic cell is ensured. [Means for solving the problem]

[0006] In light of the above facts recognized by the inventors, the present inventors have determined that the effective flow passage cross-sectional area CD of the cathode side fluid discharge passage is larger than the effective flow passage cross-sectional area CS of the cathode side fluid supply passage, and that the effective flow passage cross-sectional area CD of the anode side fluid supply passage is larger than the effective flow passage cross-sectional area CS of the cathode side fluid supply passage. ExcretionIt has been found that the above-mentioned main technical object can be achieved by making the effective flow passage cross-sectional area AD of the outlet passage larger than the effective flow passage cross-sectional area AS of the anode-side fluid supply passage.

[0007] That is, according to the present invention, an electrolytic cell that achieves the above-mentioned main technical object is an anode frame having an anode plate fixed to its inner surface; an ion exchange membrane disposed between the cathode frame and the anode frame; a cathode side fluid supply passage 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 passage for discharging the cathode side fluid from the cathode chamber; an anode side fluid supply passage 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 passage for discharging the anode side fluid from the anode chamber, an effective flow path cross-sectional area CD of the cathode side fluid discharge path is larger than an effective flow path cross-sectional area CS of the cathode side fluid supply path, and an effective flow path cross-sectional area AD of the anode side fluid discharge path is larger than an effective flow path cross-sectional area AS of the anode side fluid supply path; An electrolytic cell is provided.

[0008] The effective channel cross-sectional area CD is the effective channel cross-sectional area. product 1.1 to 3.0 times CS (CD=1.1 to 3.0CS), and the effective flow passage cross-sectional area AD is the effective flow passage cross-sectional area product AD=1.1 to 3.0 times AS (AD=1.1 to 3.0AS). In particular, the effective flow area CD is the effective flow area product CD=1.5 to 2.5 times CS (CD=1.5 to 2.5CS), and the effective flow passage cross-sectional area AD is the effective flow passage cross-sectional area product It is preferably 1.5 to 2.5 times AS (AD=1.5 to 2.5 AS).

[0009] In a preferred embodiment, the cathode frame is provided with at least one upper flow passage extending from an upper opening located at an upper end of the inner surface and at least one lower flow passage 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 passage extending from an upper opening located at an upper end of the inner surface and at least one lower flow passage extending from a lower opening located at a lower end of the inner surface; the cathode plate extends continuously from above the upper opening of the cathode frame to below the lower opening of the cathode frame, an upper end of the cathode plate is formed with at least one upper through-opening that aligns with the upper opening of the cathode frame, and a lower end of the cathode plate is formed with at least one lower through-opening that aligns with the lower opening of the cathode frame; the anode plate extends continuously from above the upper opening of the anode frame to below the lower opening of the anode frame, At least one upper through-opening is formed in an upper end of the anode plate, the upper through-opening being aligned with the upper opening of the anode frame, and at least one lower through-opening is formed in a lower end of the anode plate, the lower through-opening being aligned with the lower opening of the anode frame; The upper through opening of the cathode plate and the upper flow passage of the cathode frame are connected to the cathode side fluid discharge passage and the cathode side fluid The cathode plate has a lower through opening and the lower flow passage of the cathode frame is connected to the cathode side fluid discharge passage and the cathode side fluid supply passage. fluid Constituting the other of the supply channel, The upper through opening of the anode plate and the upper flow passage of the anode frame are connected to the anode side fluid discharge passage and the anode side fluid The anode side fluid discharge path and the anode side fluid supply path are connected to each other by the lower through opening of the anode plate and the lower flow path of the anode frame. fluid It constitutes the other of the supply paths.

[0010] Preferably, the cathode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at an upper end of the inner surface at intervals in the width direction, and a plurality of lower flow paths extending from a plurality of lower openings arranged at a lower end of the inner surface at intervals in the width direction, the anode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at an upper end of the inner surface at intervals in the width direction, and a plurality of lower flow paths extending from a plurality of lower openings arranged at a lower end of the inner surface at intervals in the width direction, a plurality of upper through-openings are formed at an upper end of the cathode plate, each of which is aligned with one of the plurality of upper openings of the cathode frame; and a plurality of lower through-openings are formed at a lower end of the cathode plate, each of which is aligned with one of the plurality of lower openings of the cathode frame; a plurality of upper through-openings are formed at an upper end of the anode plate, each of which is aligned with one of the plurality of upper openings of the anode frame; and a plurality of lower through-openings are formed at a lower end of the anode plate, each of which is aligned with one of the plurality of lower openings of the anode frame; The cathode side fluid The number of the upper through openings of the cathode plate and the upper flow passages of the cathode frame, or the number of the lower through openings of the cathode plate and the lower flow passages of the cathode frame, which constitute the discharge passage, is determined based on the number of the upper through openings of the cathode plate and the upper flow passages of the cathode frame. fluid the number of the lower through openings of the cathode plate and the lower flow paths of the cathode frame constituting the supply path, or the number of the upper through openings of the cathode plate and the upper flow paths of the cathode frame constituting the supply path, The anode side fluid The number of the upper through openings of the anode plate and the upper flow passages of the anode frame constituting the discharge passage or the number of the lower through openings of the anode plate and the lower flow passages of the anode frame is determined based on the anode side. fluid The number of the supply passages is greater than the number of the lower through openings of the anode plate and the lower flow passages of the anode frame or the number of the upper through openings of the anode plate and the upper flow passages of the anode frame that constitute the supply passages.

[0011] Advantageously, the upper and lower openings of the cathode frame and the upper and lower openings of the cathode plate have a circular cross-sectional shape, and the upper and lower openings of the anode frame and the upper and lower openings of the anode plate have a circular cross-sectional shape. The cathode plate and the anode plate are preferably constructed from rectangular plates.

[0012] In a preferred embodiment of the present invention, at least one cation exchange membrane is disposed between the cathode plate and the anode plate in the electrolytic cell as described above, and an aqueous solution of a quaternary ammonium salt is prepared by using the electrolytic cell. and This produces an aqueous solution of quaternary ammonium hydroxide. Effect of the Invention

[0013] In the electrolytic cell of the present invention, the effective flow passage cross-sectional area CD of the cathode side fluid discharge passage is larger than the effective flow passage cross-sectional area CS of the cathode side fluid supply passage, discharge Since the effective flow path cross-sectional area AD of the anode side fluid supply path is larger than the effective flow path cross-sectional area AS of the anode side fluid supply path, as will be clearly understood from the examples described later, an increase in electrolysis voltage is avoided and stable operation of the electrolytic cell is ensured. [Brief description of the drawings]

[0014] [Figure 1] 1 is a simplified cross-sectional view of a preferred embodiment of an electrolytic cell constructed in accordance with the present invention; [Diagram 2] 2 is a simplified cross-sectional view taken along line II-II in FIG. 1, showing a cathode frame and a cathode plate in the electrolytic cell shown in FIG. 1; [Diagram 3] 2 is a partially enlarged cross-sectional view showing an upper opening of a cathode frame, an upper through-opening formed in a cathode plate, and an upper communication opening formed in a gasket in the electrolytic cell shown in FIG. [Figure 4] 3 is a simplified cross-sectional view similar to that of FIG. 2, showing a cathode frame and a cathode plate in a modified electrolytic cell constructed in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will now be described in further detail with reference to the accompanying drawings, which show preferred embodiments of an electrolytic cell constructed in accordance with the present invention.

[0016] 1 and 2, the illustrated electrolytic cell constructed according to the present invention includes a hollow rectangular parallelepiped housing 2 constituted by a cathode frame 4 (FIG. 1), an anode frame 6 (FIG. 1), a cathode side upper wall member 8, an anode side upper wall member 10, a cathode side lower wall member 12, an anode side lower wall member 14, a cathode side front wall member 16 (FIG. 2), an anode side front wall member (not shown), a cathode side rear wall member 18 (FIG. 2), and an anode side rear wall member (not shown). 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 (the right end surface in Fig. 1 ) of the cathode side upper wall member 8 is connected to the inner upper edge portion of the cathode frame 4 by an appropriate connecting means such as a fastening screw or an adhesive, and the base end surface (the right end surface in Fig. 1 ) of the cathode side lower wall member 12 is connected to the inner lower edge portion of the cathode frame 4 by an appropriate connecting means. Similarly, the base end surface (the left end surface in Fig. 1 ) of the anode side upper wall member 10 is connected to the inner upper edge portion of the anode frame 6 by an appropriate connecting means, and the base end surface (the left end surface in Fig. 1 ) of the anode side lower wall member 14 is connected to the inner lower edge portion of the anode frame 6 by an appropriate connecting means. The cathode side front wall member 16 is connected to the front surface of the cathode frame 4, and the anode side front wall member is connected to the front surface of the anode frame 6 by an appropriate connecting means, while the cathode side rear wall member 18 is connected to the rear surface of the cathode frame 4, and the anode side rear wall member is connected to the rear surface of the anode frame 6 by an appropriate connecting means. Instead of connecting the cathode side and anode side 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 to the cathode frame 4 or the anode frame 6 as described above, these wall members can be formed integrally in advance and connected to the cathode frame 4 or the anode frame 6. Also, the wall portions can 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 through a sealing member. As the sealing member, an extension portion of a gasket 38 described below can be used by extending the gasket 38 from a size corresponding to the cathode plate 32 or the anode plate 56 to a size corresponding to the cathode frame 4 or the anode frame 6.The cathode frame 4, anode frame 6, 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, anode side front wall member, cathode side rear wall member 18, and anode side rear wall member may be in the form of a solid block or plate except for the openings and flow paths described below, and may be formed from an appropriate synthetic resin such as an olefin-based resin such as polypropylene and polyethylene, a vinyl chloride-based resin, or a fluorine-based resin. An appropriate sealing member (not shown) such as a gasket is provided between mutually connecting portions of the cathode frame 4, anode frame 6, 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, anode side front wall member, cathode side rear wall member 18, and anode side rear wall member. intervention It can be done.

[0017] Continuing the explanation with reference to FIG. 3 as well as FIG. 1 and FIG. 2, a plurality of (six in the illustrated case) upper openings 20 (one of which is shown by a dashed line and one of which is shown by a solid line in FIG. 1 and FIG. 3, respectively) are formed at equal intervals in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIG. 2) at the upper end of the inner surface of the cathode frame 4 (the upper end of the inner surface of the cathode frame 4 is shown in FIG. 1 and FIG. 3, respectively) and a plurality of (six in the illustrated case) upper flow paths 22 (one of which is shown by a dashed line and one of which is shown by a solid line in FIG. 1 and FIG. 3, respectively) are formed in the cathode frame 4, extending substantially horizontally from each of the upper openings 20 and penetrating the cathode frame 4. Similarly, a plurality of (three in the illustrated case) lower openings 24 (one of which is shown by a broken line in FIG. 1) are formed at equal intervals in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIG. 2) at the lower end of the inner surface (the left side surface in FIG. 1) of the cathode frame 4, and a plurality of (three in the illustrated case) lower flow paths 26 (one of which is shown by a broken line in FIG. 1) are formed in the cathode frame 4, extending substantially horizontally from each of the lower openings 24 and penetrating the cathode frame 4. 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 matching the circular shapes 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) arranged on the outside of the housing 2, and the outer flow path 31 (part of which is shown in FIG. 2) is also provided with a circulation pump, a product storage tank, and multiple valve members for flow control (the outer flow path and the above-mentioned components arranged therein are well known to those skilled in the art, so a detailed description thereof will be omitted in this specification).

[0018] 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 above the upper opening 20 formed in the cathode frame 4 to below the lower opening 24 formed in the cathode frame 4. The cathode plate 32 is a rectangular plate made of a suitable conductive metal such as nickel, and its upper end surface abuts or is close to the inner surface (i.e., the lower surface) of the cathode side upper wall member 8, its lower end surface abuts or is close to the inner surface (i.e., the upper surface) of the cathode side lower wall member 12, its front side surface abuts or is close to the inner surface (i.e., the rear surface) of the front wall member 16, and its rear side surface abuts or is close to the inner surface (i.e., the front surface) of the rear wall member 18. The cathode plate 32 can be conveniently fixed to the cathode frame 4 by, for example, screwing fastening screws (not shown) through the cathode plate 32 to the cathode frame 4 at the four corners of the cathode plate 32. A plurality of (six in the illustrated case) upper through openings 34 are formed at the upper end of the cathode plate 32 at equal intervals in the width direction (direction perpendicular to the paper surface in FIG. 1, left-right direction in FIG. 2), and a plurality of (three in the illustrated case) lower through openings 36 are formed at the lower end of the cathode plate 32 at equal intervals in the width direction (direction perpendicular to the paper surface in FIG. 1, left-right direction in FIG. 2) (the upper through openings 34 and the lower through openings 36 will be further mentioned later). Each of the upper through openings 34 formed in the cathode plate 32 is positioned in alignment with each of the upper openings 20 formed in the upper end of the cathode frame 4. of In the embodiment, each of the upper through openings 34 has the same shape (hence, circular) and the same dimensions as each of the upper openings 20. Similarly, it is important that each of the lower through openings 36 formed in the cathode plate 32 is positioned in registration with each of the lower openings 24 formed in the lower end of the cathode frame 4. In the illustrated embodiment, each of the lower through openings 36 has the same shape (hence, circular) and the same dimensions as each of the lower openings 24. It is preferable that the upper through openings 34 (and the upper openings 20) are positioned close to the upper end of the cathode plate 32, and the lower through openings 36 (and the lower openings 24) are positioned close to the lower end of the cathode plate 32.

[0019] Continuing the explanation with reference to Figure 3 in addition to Figure 1, it is preferable to interpose a gasket 38 between the cathode frame 4 and the cathode plate 32. The gasket 38 enables the cathode plate 32 to be stably fixed to the cathode frame 4, and also prevents corrosion and the like caused by the penetration of liquid into the interface between the cathode frame 4 and the cathode plate 32. This gasket 38 may be a rectangular plate having substantially the same dimensions as the cathode plate 32 (as mentioned above, the gasket 38 can also be sized to correspond to the cathode frame 4), and may be made of an appropriate elastomer, for example, silicone rubber, ethylene propylene rubber, chloroform rubber, or the like. PThe gasket 38 may be made of polyethylene rubber, soft polyvinyl chloride, butyl rubber, butadiene rubber or fluororubber. When the gasket 38 is interposed between the cathode frame 4 and the cathode plate 32, fastening screws (not shown) can be screwed into the cathode frame 4 through the gasket 38 together with the cathode plate 32 at the four corners of the cathode plate 32. The upper end of the gasket 38 is formed with a plurality of upper communication openings 40 (six in the illustrated case) that communicate with each of the upper through openings 34 formed in the cathode plate 32 and each of the upper openings 20 formed in the cathode frame 4, and the lower end of the gasket 38 is formed with a plurality of lower communication openings 42 (three in the illustrated case) that communicate with each of the lower through openings 36 formed in the cathode plate 32 and each of the lower openings 24 formed in the cathode frame 4. See FIG. 3. As will be clearly understood from the above, it is desirable that the upper communication opening 40 and the lower communication opening 42 formed in the gasket 38 are 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, the electrolytic cell is operated continuously, and the gas The skirt 38 expands somewhat, causing the upper communication opening 40 and the lower communication opening 42 to shrink and be displaced, which tends to cause 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 become insufficient or to be damaged. The upper communication opening 40 and the lower communication opening 42 may be circular, having a diameter greater than the diameters 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 openings 40 and the lower communication openings 42 do not necessarily have to be concentric with the upper through openings 34 and the upper openings 20, and the lower through openings 36 and the lower openings 24, but may be eccentric. The diameters of the upper communication openings 40 and the lower communication openings 42 and the degree of eccentricity with respect to the upper through openings 34 and the upper openings 20, and the lower through openings 36 and the lower openings 24 can be set experimentally based on the expansion and displacement of the gasket 38 due to the continuous operation of the electrolytic cell.The larger the upper and lower communication openings 40 and 42 formed in the gasket 38 are, the less likely the communication will be insufficient or damaged. However, as described below, the area of ​​the back surface of the cathode plate 32 that comes into contact with the liquid increases, which causes electrolytic corrosion and corrosion, and increases the amount of electrode metal mixed into the liquid. For this reason, the preferred sizes of the upper and lower communication openings 40 and 42 formed in the gasket 38 are +30 mm or less, preferably +20 mm or less, and more preferably +10 mm or less, of the upper through openings 34 and the upper openings 20 and the lower through openings 36 and the lower openings 24. If a material that does not expand easily is used for the gasket 38, the possibility of the communication being insufficient or damaged is low even if the size of the upper and lower communication openings 40 and 42 is close to the size of the upper through openings 34 and the upper openings 20 and the lower through openings 36 and the lower openings 24. For this reason, the material used for the gasket 38 should have a linear expansion coefficient of . I like Preferably 3 x 10 -4 (1 / ℃) or less, more preferably 1.5×10 -4 (1 / ℃) or less, most preferably 1×10 -4 (1 / ℃) or less.

[0020] In the illustrated embodiment, the anode frame 6 is substantially the same as the cathode frame 4 described above. More specifically, the cathode frame 4 and the anode frame 6 are symmetrical with respect to a virtual plane extending perpendicular to the paper surface in FIG. 1. Thus, the anode frame 6 is provided with an upper opening 44, an upper flow passage 46, a lower opening 48, and a lower flow passage 50. To avoid repetition, detailed descriptions of the upper opening 44, the upper flow passage 46, the lower opening 48, and the lower flow passage 50 are omitted. The upper flow passage 46 and the lower flow passage 50 are connected by an outer flow passage (not shown) provided outside the housing 2, and the outer flow passage is provided with a circulation pump, a raw material storage tank, a plurality of valve members for flow control, and the like (the outer flow passage and the above-mentioned components provided therein are well known to those skilled in the art, and detailed descriptions thereof are omitted in this specification).

[0021] An anode plate 56 is fixed to the inside surface of the anode frame 6. In the illustrated embodiment, the anode plate 56 is substantially the same as the cathode plate 32 described above, except that it is made of any suitable conductive metal suitable for an anode, such as titanium with an indium oxide plated surface. pole plate 1. The anode plate 56 and the anode 32 are symmetrical with respect to a virtual plane extending perpendicularly to the paper surface in FIG. 1. Therefore, the anode plate 56 extends continuously from above the upper opening 44 formed in the anode frame 6 to below the lower opening 48 formed in the anode frame 6. exists The anode plate 56 has a rectangular shape. An upper through-opening 58 and a lower through-opening 60 are formed in the anode plate 56, which are aligned with the upper opening 44 and the lower opening 48, respectively, formed in the anode frame 6. To avoid duplication, a detailed description of the anode plate 56 will be omitted.

[0022] In the illustrated embodiment, a gasket 62 is also interposed between the anode frame 6 and the anode plate 56. This gasket 62 is also substantially the same as the gasket 38 interposed between the cathode frame 4 and the cathode plate 32. More specifically, the gasket 38 and the gasket 62 are symmetrical with respect to a virtual plane extending perpendicular to the paper surface in FIG. 1. Therefore, the gasket 62 has an upper communicating opening 64 that communicates the upper opening 44 formed in the anode frame 6 with the upper through opening 58 formed in the anode plate 56, as well as a lower opening 48 that communicates with the lower through opening 60 formed in the anode frame 6 with the lower through opening 60 formed in the anode plate 56. Below In order to avoid duplication of explanation, detailed explanation of the gasket 62 and the upper and lower communication openings 64 and 66 will be omitted.

[0023] 1, in the illustrated embodiment, a cation exchange membrane 68 is disposed between the cathode plate 32 and the anode plate 56. The cation exchange membrane 68, which may be of a known form, has a rectangular plate shape, with its upper edge being held between the cathode side upper wall member 8 and the anode side upper wall member 10, and its lower edge being held between the cathode side lower wall member 12 and the anode side lower wall member 14. ToThe front edge portions of the cathode frame 4 and the anode frame 6 are held between the cathode side front wall member 16 and the anode side front wall member, and the rear edge portions of the cathode frame 4 and the anode frame 6 are held between the cathode side rear wall member 18 and the anode side rear wall member. To Appropriate seal members (not shown) are interposed between the cation exchange membrane 68 and each of 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, the cathode side front wall member 16 and the anode side front wall member, and the cathode side rear wall member 18 and the anode side rear wall member. But Cut.

[0024] In the electrolytic cell as described above, a cathode chamber or product chamber 70 is defined between the cathode plate 32 and the cation exchange membrane 68, and an anode chamber or raw material chamber 72 is defined between the anode plate 56 and the cation exchange membrane 68. Initially, a diluted aqueous solution of quaternary ammonium hydroxide (or pure water) is circulated through the product chamber 70, more specifically, it flows into the product chamber 70 through one of the lower flow passage 26 and the upper flow passage 22 formed in the cathode frame 4, and flows out of the product chamber 70 through the other. At the same time, an aqueous solution of quaternary ammonium salt is circulated through the raw material chamber 72, more specifically, it flows into the raw material chamber 72 through one of the lower flow passage 50 and the upper flow passage 46 formed in the anode frame 6, and flows out through the other. An electrolytic voltage is applied between the cathode plate 32 and the anode plate 56. Thus, the concentration of the aqueous solution of quaternary ammonium hydroxide circulating through the product chamber 70 is gradually increased. Such electrolytic action is well known to those skilled in the art, so a detailed description thereof is omitted in this specification. In the illustrated embodiment of the electrolytic cell constructed according to the present invention, the cathode plate 32 and the anode plate 56 each extend continuously from above the upper openings 20 and 44 formed in the cathode frame 4 and the anode frame 6 to below the lower openings 24 and 48, and upper through-openings 34 and 58 and lower through-openings 36 and 60 aligned with the upper openings 20 and 44 and the lower openings 24 and 48 are formed in the cathode plate 32 and the anode plate 56, respectively. Therefore, the cathode plate 32 and the anode plate 56 extend over almost the entire inner surface of the cathode frame 4 and the anode frame 6, respectively. Therefore, the relative current-carrying areas of the cathode plate 32 and the anode plate 56 with respect to the size of the electrolytic cell are large, and thus electrolysis is performed with improved electrolysis efficiency.

[0025] In electrolytic cells constructed in accordance with the present invention, it is important that the effective cross-sectional area CD of the cathode fluid outlet is greater than the effective cross-sectional area CS of the cathode fluid supply, and similarly, the effective cross-sectional area AD of the anode fluid outlet is greater than the effective cross-sectional area AS of the anode fluid supply. The term "effective cross-sectional area" refers to the smallest cross-sectional area in a flow path. In the illustrated embodiment, the cathode fluid outlet is Effective flow area ofCD is defined by the six upper through openings 34 formed in the cathode plate 32, as well as the upper communication openings 40 continuing from the upper through openings 34, the upper openings 20, the upper flow passages 22 and a portion of the outer flow passage 31, and the cross-sectional areas of the upper communication openings 34, the upper openings 20, the upper flow passages 22 and a portion of the outer flow passage 31 are the same as or larger than the cross-sectional area of ​​the upper through openings 34. Therefore, the effective flow passage 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 passage cross-sectional area CS of the cathode-side fluid supply passage is determined by the three lower through-openings 36 formed in the cathode plate 32, as well as the lower communication openings 42, the lower openings 24, the lower flow passages 26, and a part of the outer flow passage 31 that are continuous with the lower through-openings 36. The cross-sectional areas of the lower communication openings 42, the lower openings 24, the lower flow passages 26, and the part of the outer flow passage 31 are equal to or larger than the cross-sectional area of ​​the lower through-openings 36. supply Effective flow area C of the channel S is determined by the total cross-sectional area of ​​the three lower through openings 36. In particular, from the viewpoint of suppressing an increase in back pressure due to the discharged fluid, it is preferable that the cross-sectional area of ​​the portion of the outer flow passage 31 is larger than the cross-sectional area of ​​the upper through opening 34 to the lower through opening 36. Specifically, the cross-sectional area of ​​the portion of the outer flow passage 31 is preferably 1.0 times or more, and more preferably 1.5 times or more, of the cross-sectional area of ​​the upper through opening 34 to the lower through opening 36. The cross-sectional area of ​​the portion of the outer flow passage 31 relative to the upper through opening 34 to the lower through opening 36 is appropriately determined taking into consideration the effective flow passage cross-sectional area and the supply amount of fluid.

[0026] In the illustrated embodiment, as described above, six upper through openings 34 are formed at equal intervals in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIG. 2), whereas three lower through openings 36 are formed at equal intervals in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIG. 2). penetrationThe cross-sectional areas of the openings 36 are all the same. 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 will be understood from the examples described later, the effective flow path cross-sectional area CD of the cathode-side fluid discharge path is preferably 1.1 to 3.0 times (CD = 1.1 to 3.0CS) and particularly 1.5 to 2.5 times (CD = 1.5 to 2.5CS) the effective flow path cross-sectional area CS of the cathode-side fluid supply path.

[0027] It is desirable to set the cross-sectional area of ​​the upper through-opening 34 and the lower through-opening 36 formed in the cathode plate 32 to the minimum necessary to achieve maximum electric field efficiency. ~Product room 70 In the cathode-side fluid discharge channel, gas is generated due to electrolysis, and in addition to the cathode-side fluid, the generated gas also flows in the cathode-side fluid discharge channel. Therefore, if the effective flow cross-sectional area CD of the cathode-side fluid discharge channel is set to be the same as the effective flow cross-sectional area CS of the cathode-side fluid supply channel, the flow rate in the cathode-side fluid discharge channel is increased compared to the cathode-side fluid supply channel, generating back pressure, which tends to increase the electrolysis voltage and hinder stable operation of the electrolytic cell. However, in the electrolytic cell constructed according to the present invention, the effective flow cross-sectional area CD of the cathode-side fluid discharge channel is set to be larger than the effective flow cross-sectional area CS of the cathode-side fluid supply channel, and therefore, as will be clearly understood from the examples described later, an increase in the electrolysis voltage is avoided and stable operation of the electrolytic cell is ensured.

[0028] In the embodiment illustrated in FIGS. 1 to 3 as described above, the number of the upper through openings 34 (six) is greater than the number of the lower through openings 36 (three) to make the effective flow path cross-sectional area CD of the cathode-side fluid discharge path greater than the effective flow path cross-sectional area CS of the cathode-side fluid supply path; however, if desired, the numbers of the upper through openings 34 and the lower through openings 36 can be made the same and the cross-sectional area of ​​each of the upper through openings 34 can be set greater than the cross-sectional area of ​​each of the lower through openings 36 to make the effective flow path cross-sectional area CD of the cathode-side fluid discharge path greater than the effective flow path cross-sectional area CS of the cathode-side fluid supply path. In the modification shown in FIG. 4, three upper through openings 34 are formed at the upper end of the cathode plate 32 at equal intervals in the width direction (left-right direction in FIG. 4) (thus, three upper communication openings 40, three upper openings 20, and three upper flow paths 22 are also formed), and three lower through openings 36 are formed at the lower end of the cathode plate 32 at equal intervals in the width direction (left-right direction in FIG. 4). The cross-sectional area of ​​each of the upper through openings 34 is product However, according to the experience of the present inventors, the discharge flow tends to be smoother when the number of the upper through openings 34 is made greater than the number of the lower through openings 36, rather than when the cross-sectional area of ​​each of the upper through openings 34 is set greater than the cross-sectional area of ​​each of the lower through openings 36.

[0029] In the above-described embodiment and modified example, a plurality of upper through openings 34 and lower through openings 36 are formed in the cathode plate 32 at equal intervals in the width direction. However, if desired, a single upper through opening and a single lower through opening extending elongatedly in the width direction can be formed in the cathode plate 32, and the cross-sectional area of ​​the upper through opening 34 can be made larger than the cross-sectional area of ​​the lower through opening 36.

[0030] Furthermore, the above-mentioned implementation formIn the modified example, the cathode plate 32 extends continuously from above the upper opening 20 formed in the cathode frame 4 to below the lower opening 24 formed in the cathode frame 4, and a plurality of upper through-openings 34 are formed at the upper end of the cathode plate 32 at equal intervals in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIGS. 2 and 4), and a plurality of lower through-openings 34 are formed at the lower end of the cathode plate 32 at equal intervals in the width direction (the direction perpendicular to the paper surface in FIG. 1, the left-right direction in FIGS. 2 and 4). However, if desired, for example, the cathode plate 32 may be shaped to extend from below the upper opening 20 formed in the cathode frame 4 to above the lower opening 24 formed in the cathode frame 4, without forming the upper through opening 34 and the lower through opening 36 in the cathode plate 32, and the upstream end of the cathode-side fluid discharge path may be defined by the upper opening 20 formed in the cathode frame 4, and the downstream side of the cathode-side fluid supply path may be defined by the lower opening 24 formed in the cathode frame 4. In such a 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 openings 20, and the effective flow path cross-sectional area of ​​the cathode-side fluid supply path may be defined by the total cross-sectional area of ​​the upper openings 20. valid The flow cross-sectional area is defined by the total cross-sectional area of ​​the lower openings 24 .

[0031] 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 has been specifically described, but 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, and therefore, to avoid redundancy, a 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 will be omitted.

[0032] Examples 1 to 3 and Comparative Example 1 An electrolytic cell having the configuration shown in FIG. 1 to FIG. 3 or FIG. 4 was prepared, operated in a constant current control mode, and the average value of the cell voltage (voltage between the anode plate and the cathode plate) during operation was detected. In Examples 1 to 3, the effective flow path cross-sectional area CD of the cathode side fluid discharge path was 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 was 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 and the effective flow path cross-sectional area CS of the cathode side fluid supply path were the same, and similarly, 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 were the same. The average value of the cell voltage was as shown in Table 1.

[0033] The details of the components of the electrolytic cell and their operating conditions are as follows: Operating time: 30 days Cathode: Nickel plate (thickness 2 mm, surface dimensions 1 m x 1 m) Anode: Titanium plate with indium oxide plating on the surface (thickness 2 mm, Surface dimensions: 1m x 1m Cation exchange membrane: product name from Chemours Company Replacement membrane (1mm thick) sold as "N324" Gasket: EPDM (The diameter of the upper and lower communication openings is the corresponding upper Diameter of side through opening and lower through opening Rifu (2mm larger) Raw material (anode fluid): Methylammonium chloride aqueous solution Product (cathode fluid): Methylammonium hydroxide solution Current: 1000A(10A / dm 2 ) Operating temperature: 70℃ Electrolytic cell assembly temperature: 20℃ Raw material (anode side fluid) flow rate: 20L / min Product (cathode side fluid) flow rate: 20L / min

[0034] [Table 1]

[0035] Although the present invention has been described in detail with reference to the attached drawings illustrating preferred embodiments thereof, it goes without saying that the present invention is not limited to such embodiments, and various modifications and alterations are possible without departing from the technical scope of the present invention. For example, in the illustrated embodiment, one cation exchange membrane 68 is disposed 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 disposed between the cathode plate 32 and the anode plate 56. [Explanation of symbols]

[0036] 2: Electrolyzer housing 4: Cathode frame 6:Anode frame 8: Cathode side upper wall member 10: Anode side upper wall member 12: Cathode side lower wall member 14: Anode side lower wall member 16: Cathode side front wall member 18: Cathode side rear wall member 20: Upper opening 22: Upper channel 24: Lower opening 26:Lower channel 31:Outer channel 32: Cathode plate 34: Upper through opening 36: Lower through opening 38: Gasket 40: Upper communication opening 42: Lower communication opening 44: Upper opening 46: Upper channel 48: Lower opening 50: Lower flow path 56: Anode plate 58: Upper through opening 60: Lower through opening 62: Gasket 64: Upper communication opening 66: Lower communication opening 68: Cation exchange membrane 70: Product room (cathode room) 72: Raw material room (anode room)

Claims

1. An electrolytic cell for producing an aqueous solution of quaternary ammonium hydroxide from an aqueous solution of a quaternary ammonium salt, comprising: the cathode frame having a cathode plate fixed to its inner surface, an anode frame having an anode plate fixed to its inner surface, an ion exchange membrane disposed between the cathode frame and the anode frame, a cathode side fluid supply passage 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 passage for discharging the cathode side fluid from the cathode chamber, an anode side fluid supply passage 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 passage for discharging the anode side fluid from the anode chamber, an effective flow path cross-sectional area CD of the cathode side fluid discharge path is larger than an effective flow path cross-sectional area CS of the cathode side fluid supply path, and an effective flow path cross-sectional area AD of the anode side fluid discharge path is larger than an effective flow path cross-sectional area AS of the anode side fluid supply path, the cathode frame is provided with at least one upper flow passage extending from an upper opening located at an upper end of the inner surface and at least one lower flow passage 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 passage extending from an upper opening located at an upper end of the inner surface and at least one lower flow passage extending from a lower opening located at a lower end of the inner surface; the cathode plate extends continuously within the cathode chamber from above the upper opening of the cathode frame to below the lower opening of the cathode frame, At least one upper through-opening is formed in an upper end of the cathode plate, the upper through-opening being aligned with the upper opening of the cathode frame, and at least one lower through-opening is formed in a lower end of the cathode plate, the lower through-opening being aligned with the lower opening of the cathode frame; the anode plate extends continuously within the anode chamber from above the upper opening of the anode frame to below the lower opening of the anode frame, At least one upper through-opening is formed in an upper end of the anode plate, the upper through-opening being aligned with the upper opening of the anode frame, and at least one lower through-opening is formed in a lower end of the anode plate, the lower through-opening being aligned with the lower opening of the anode frame; 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. Electrolytic cell characterized in that

2. 2. The electrolytic cell of claim 1, wherein said effective cross-sectional area CD is 1.1 to 3.0 times said effective cross-sectional area CS (CD=1.1 to 3.0CS) and said effective cross-sectional area AD is 1.1 to 3.0 times said effective cross-sectional area AS (AD=1.1 to 3.0AS).

3. 3. An electrolytic cell according to claim 2, wherein said effective cross-sectional area CD is 1.5 to 2.5 times said effective cross-sectional area CS (CD=1.5 to 2.5CS) and said effective cross-sectional area AD is 1.5 to 2.5 times said effective cross-sectional area AS (AD=1.5 to 2.5AS).

4. the cathode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at an upper end of the inner surface at intervals in the width direction, and a plurality of lower flow paths extending from a plurality of lower openings arranged at a lower end of the inner surface at intervals in the width direction, the anode frame is provided with a plurality of upper flow paths extending from a plurality of upper openings arranged at an upper end of the inner surface at intervals in the width direction, and a plurality of lower flow paths extending from a plurality of lower openings arranged at a lower end of the inner surface at intervals in the width direction, a plurality of upper through-openings are formed at an upper end of the cathode plate, each of which is aligned with one of the plurality of upper openings of the cathode frame; and a plurality of lower through-openings are formed at a lower end of the cathode plate, each of which is aligned with one of the plurality of lower openings of the cathode frame; a plurality of upper through-openings are formed at an upper end of the anode plate, each of which is aligned with one of the plurality of upper openings of the anode frame; and a plurality of lower through-openings are formed at a lower end of the anode plate, each of which is aligned with one of the plurality of lower openings of the anode frame; the number of the upper through openings of the cathode plate and the upper flow paths of the cathode frame or the lower through openings of the cathode plate and the lower flow paths of the cathode frame constituting the cathode side fluid discharge path is greater than the number of the lower through openings of the cathode plate and the lower flow paths of the cathode frame or the upper through openings of the cathode plate and the upper flow paths 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 paths of the anode frame or the lower through openings of the anode plate and the lower flow paths 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 paths of the anode frame or the upper through openings of the anode plate and the upper flow paths of the anode frame constituting the anode-side fluid supply path.

2. The electrolytic cell of claim 1.

5. 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 a circular cross-sectional shape; 5. The electrolytic cell of claim 4.

6. 2. The electrolytic cell of claim 1, wherein said cathode plate and said anode plate comprise rectangular plates.

7. 4. A method for producing an aqueous solution of quaternary ammonium hydroxide from an aqueous solution of a quaternary ammonium salt as a raw material, using the electrolytic cell according to claim 1, wherein at least one cation exchange membrane is disposed between the cathode plate and the anode plate.

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