JPH0588319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a filter press type ion exchange membrane method electrolytic cell in which electrolysis is carried out while circulating an electrolytic solution.

(Prior art) Ion-exchange membrane electrolysis that uses an ion-exchange membrane with high ion selectivity in place of the conventional mercury method and diaphragm method as an electrolytic cell for producing a high-purity caustic aqueous solution from salt water. A tank is proposed. As one type of ion-exchange membrane electrolytic cell, a filter press type ion-exchange membrane electrolytic cell has been developed in which an anode unit and a cathode unit are separated by a planar ion-exchange membrane. In the so-called overflow type electrolytic cell (Utility Model Publication No. 153376/1983), in which the electrolytic solution is supplied from the bottom of the electrolytic cell and the liquid is extracted from the top of the electrolytic cell, the supplied electrolytic solution does not circulate. Since the electrolyte solution is taken out from the electrode chamber at the same time, the residence time of the electrolyte solution is short and a high concentration caustic alkaline aqueous solution cannot be produced. If the electrolytic solution once taken out from the electrolytic cell is supplied again to the electrolytic cell, a highly concentrated caustic alkaline aqueous solution can be produced, but this is not preferable because the operation becomes complicated and new piping needs to be installed.

(Problems to be Solved by the Invention) The present invention provides a filter press type ion exchange membrane method electrolytic cell that enables sufficient circulation of the electrolytic solution in the electrolytic cell to produce a highly concentrated caustic alkaline aqueous solution. This is what we are trying to provide.

[Structure of the invention]

The present invention provides a filter press type ion exchange membrane method in which frame-shaped electrode gaskets constituting an anode chamber and a cathode chamber are laminated with a flat ion exchange membrane interposed therebetween to divide the electrolytic cell body into an anode chamber and a cathode chamber. In an electrolytic cell, an electrode chamber of an anode chamber or a cathode chamber and a manifold having an inner tube for supplying an electrolyte therein and having an electrolyte circulation passage hole and an electrolyte supply passage hole at the bottom are connected to the electrode gasket and the manifold. At least the connecting edge of the electrode gasket with the connecting tube is formed of a hollow pipe, and the inner circumferential surface of the connecting tube on the connecting tube side of the hollow pipe and the circumferential surface of the electrode side are One or more circular holes are bored in each hole to communicate the electrode chamber and the manifold, connect the electrolyte supply pipe to the electrolyte supply passage hole, and connect the inside of the connecting pipe and the hollow pipe. This is a filter press type ion exchange membrane method electrolytic cell characterized by being installed so as to penetrate and reach the lower part of the electrolytic chamber to supply and circulate an electrolytic solution.

The present invention will be specifically explained below.

The anode chamber gasket and the cathode chamber gasket are frame-shaped in order to form an anode chamber and a cathode chamber inside, respectively.These gaskets have at least the connecting edge with the connecting tube formed by a hollow pipe, and the other edges are The portion may be formed of a hollow pipe or the like, but may also be formed of a rigid body. The flat ion exchange membrane has almost the same shape as both gaskets, and has cation exchange groups such as sulfonic acid groups and carboxylic acid groups to prevent anions such as halogen ions from permeating from the anode chamber to the cathode chamber. It is preferable to use perfluorocarbon resin which has high durability against generated halogen gas and high concentration caustic alkali aqueous solution. Furthermore, the electrode may be in the form of a flat plate, mesh, or the like without any limitation.

When assembling the electrolytic cell body using these members, the anode chamber gasket, the flat ion exchange membrane, the cathode chamber gasket, the flat ion exchange membrane, and the anode chamber gasket are laminated in this order and tightened from both sides. As a result, an anode chamber and a cathode chamber are formed in the anode chamber gasket and the cathode chamber gasket, respectively, which are sandwiched between the two ion exchange membranes. The anode and the cathode can be fitted into the inner edges of the anode chamber gasket and the cathode chamber gasket, respectively, or can have the same shape as the flat ion exchange membrane and can be interposed between the electrode chamber gasket and the flat ion exchange membrane. . A set of electrolytic cell bodies assembled in this manner may be used alone, or may be used by connecting a plurality of electrolytic cell bodies in the horizontal direction.

The gasket of the present invention has a hollow pipe in the part connected to the connecting pipe, usually the upper edge of the frame-shaped electrode gasket, and on the peripheral surfaces of both the connecting pipe side and the electrode chamber side. One or more circular holes, usually a plurality of circular holes, are bored to communicate the inside of the connecting tube and the electrode chamber, and at the same time, communicate with the connecting tube, and have an electrolyte circulation passage hole and a supply passage hole. The manifold and the electrode chamber are communicated through a connecting pipe and an electrode gasket.

The manifold is installed over the entire length of the electrolytic cell body, and is provided with an electrolyte supply inner tube for supplying electrolyte to the manifold. This manifold is for supplying liquid to either the anode chamber or the cathode chamber of one set of electrolytic cells. Two manifolds are required for each main body.

Each manifold is connected to a connecting tube that leads to the anode chamber or the cathode chamber via a frame-shaped electrode gasket. A liquid supply pipe is provided. Further, a circulation passageway is provided in the connecting pipe for circulating the electrolyte in the anode chamber or the cathode chamber to the manifold.

In the present invention, the electrolyte supplied to the manifold by the manifold inner tube is supplied to the anode chamber or the cathode chamber by the electrolyte supply tube, electrolyzed in each electrode chamber, and then circulated to the manifold through the circulation passage, The electrolyte is again supplied to the anode chamber or cathode chamber by the electrolyte supply pipe.

Hereinafter, the present invention will be explained in more detail based on one embodiment shown in the accompanying drawings. In this example, one manifold is installed for one set of electrolytic cell bodies,
Although only the catholyte is circulated, the present invention is not limited to this embodiment; for example, only the anolyte may be circulated, or
Two manifolds may be provided to circulate both the anolyte and the catholyte, and other members may be modified as appropriate within the scope of the present invention.

FIG. 1 is a front view showing an embodiment of a filter press type ion exchange membrane method electrolytic cell according to the present invention, FIG. 2 is a vertical sectional view taken along the line -- in FIG.
2, FIG. 4 is a cross-sectional view taken along the line -- in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line -- in FIG.

A frame-shaped cathode chamber gasket 1 is formed of a hollow pipe, and a plurality of circular holes 2 and 3 are bored in the upper and lower surfaces of the upper hollow pipe of the cathode chamber gasket 1. The anode chamber gasket 4 has the same shape as the cathode chamber gasket 1, but in this embodiment no holes are formed in the vertical direction. Between the cathode chamber gasket 1 and the anode chamber gasket 4, a frame-shaped gasket 5, a mesh-shaped cathode 6, a flat ion exchange membrane 7, and a mesh-shaped anode are arranged from the cathode chamber gasket 1 side so that their outer edges are aligned with each other. 8 and a frame-shaped gasket 5 are laminated in this order. In this embodiment, four cathode chamber gaskets 1 and 3 are used.
The anode chamber gaskets 4 are stacked with the ion exchange membrane 7 interposed therebetween as described above, and a pair of end plates 9 are disposed at both ends.
In this embodiment, the first electrolytic cell body 10 is
Three sets of electrolytic cell bodies 10 are arranged in parallel in the left-right direction in the figure.

In FIG. 5, one end of the cathode 6 of one set of electrolytic cell bodies 10 projects laterally beyond the cathode chamber gasket 1, and this protrusion extends into the anode chamber of the adjacent electrolytic cell main bodies 10 of another set. It is joined by welding or the like to the anode 8 housed therein and whose one end protrudes laterally beyond the anode chamber gasket 4 to electrically connect the two adjacent sets of electrolytic cell bodies 10, and furthermore, the joint part includes:
A through hole 11 is bored. A connecting rod 12 is inserted through the through hole 11 at the joint between the cathode 6 and the anode 8, and both ends of the connecting rod 12 are fastened to each of the pair of end plates 9 by a fastening material 13. .

A box-shaped manifold 14 whose total length is approximately equal to the total length of the electrolytic cell body 10 is installed above each electrolytic cell body 10, and the bottom plate 1 of the manifold 14 is
At the location corresponding to each cathode chamber gasket 1 in 8,
The same number of circular holes 15 as the cathode chamber gasket 1 are bored. The upper end of a cylindrical electrolyte supply pipe 16 is fitted into this circular hole 15 .
passes through a hollow pipe in the upper part of the cathode chamber gasket 1, and its lower end reaches the lower part of the cathode chamber. In this case, the hollow pipe is usually passed through the circular holes 2 and 3 bored on the upper and lower peripheral surfaces of the hollow pipe. Between the upper peripheral surface of the hollow pipe in the upper part of the cathode chamber gasket 1 and the lower surface of the manifold 14, there is a hollow pipe that surrounds the electrolyte supply pipe 16 and forms the upper edge of the cathode chamber gasket 1. A connecting pipe 17 is provided so as to cover all of the plurality of circular holes 2 bored in the upper circumferential surface.

A communication hole 19 is bored in the vicinity of the electrolyte supply pipe 16 on the bottom plate 18 of the manifold 14, and the communication hole 19, together with the circular holes 2 and 3 of the cathode chamber gasket 1, provides a circulation path for the electrolyte. is forming. Inside the manifold 14 is a cylindrical liquid supply inner tube 20 with one end closed and the other end open.
The inner tube 20 is installed so that its open end side passes through the manifold side wall and reaches the outside, and a plurality of supply holes 21 are bored in the inner tube 20 at locations corresponding to the upper part of each cathode chamber gasket 1. Manifold bottom plate 1
At the closed end side of the inner tube 20 of No. 8, an electrolytic solution outlet hole 22 is provided facing downward. On the manifold bottom plate 18 between each electrolyte supply pipe 16 and each communication hole 19 and between the electrolyte supply pipe 16 at the end and the electrolyte extraction hole 22, there is a partition plate 23 having a T-shape in plan view. are installed, and a notch 24 is bored at a portion of the partition plate 23 corresponding to each electrolyte supply pipe 16. In addition, in FIG. 1, 25 is a base frame that supports each electrolytic cell body 10.

Next, the operation of the device of this embodiment will be explained.

When a catholyte such as water or a dilute caustic alkali solution is supplied to the manifold inner tube 20, the catholyte is guided into the manifold 14 through the supply hole 21, and then supplied to the lower part of the cathode chamber through the electrolyte supply tube 16. Ru. When electrolysis is performed, sodium ions or potassium ions in the aqueous alkali chloride solution supplied to the anode chamber pass through the ion exchange membrane and move to the cathode chamber, producing a caustic aqueous solution. The catholyte in the cathode chamber whose concentration has increased due to electrolysis contains hydrogen gas generated on the cathode surface, and is supplied from the electrolyte supply pipe 16 and recirculated from the circular hole 3 on the lower circumferential surface of the electrode gasket hollow pipe, as described later. The catholyte increases due to the difference in specific gravity between the catholyte and the catholyte, and self-circulation of the catholyte occurs within the cathode chamber. Circular hole 2 drilled in the surface and lower peripheral surface
and 3, and the circulation hole 19 in the manifold bottom plate. In this case, since the cathode chamber gasket is formed by a hollow pipe, some of the catholyte
It flows through a hollow pipe at the upper edge of the cathode chamber gasket 1, and is supplied to the lower part of the cathode chamber from a circular hole 3 on the lower peripheral surface.

After the catholyte that has circulated to the manifold 14 is gas-separated there, a portion of the catholyte is passed through the electrolyte outlet hole 22.
Most of the remaining catholyte is taken out from the partition plate 23
It passes through the notch 24 and flows to the electrolyte supply pipe 16 side, and is recirculated from the electrolyte supply pipe 16 to the cathode chamber together with the catholyte supplied from the supply hole 21 of the electrolyte supply inner pipe 20. .

In this example, the catholyte is recirculated to the cathode chamber through the manifold and the hollow pipe of the cathode chamber gasket, and the catholyte remains in the cathode chamber for a long time to be sufficiently electrolyzed, thereby producing a highly concentrated caustic alkaline aqueous solution. Furthermore, since the amount of electrolyte supplied to the entire electrolytic cell is reduced, more economical operation is possible.

In this embodiment, for example, the cathode chamber gasket was formed with a hollow pipe, and a partition plate was provided in the manifold, but the present invention is not limited to these. It is also possible to form it with a rigid body or to operate it without providing a partition plate.

〔Effect of the invention〕

In the present invention, the manifold and the anode chamber or the cathode chamber are connected, and an electrolyte supply pipe and a circulation passage are used to connect the manifold and the anode chamber or the cathode chamber.
The electrolyte can be circulated. Therefore, the time the electrolyte stays in the anode chamber or the cathode chamber increases, increasing efficiency, and reducing the amount of electrolyte supplied to the electrolytic cell, resulting in a reduction in the number of tanks, etc. It becomes economical. Particularly when the catholyte is circulated, it is advantageous because a highly concentrated caustic aqueous solution can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a filter press type ion exchange membrane method electrolytic cell according to the present invention;
Figure 2 is a vertical sectional view taken along the - line in Figure 1, Figure 3 is a vertical sectional view taken along the - line in Figure 2, and Figure 4 is a vertical sectional view taken along the - line in Figure 1.
Figure 5 is a - line cross-sectional view of Figure 2.
FIG. 1... Cathode chamber gasket, 4... Anode chamber gasket, 6... Cathode, 7... Ion exchange membrane, 8...
Anode, 10... Electrolytic cell body, 14... Manifold, 16... Electrolyte supply pipe, 17... Connecting pipe, 1
9... Distribution hole, 20... Inner pipe, 23... Partition plate.

Claims (1)

[Claims] 1. In a filter press type ion exchange membrane method electrolytic cell in which the electrolytic cell body is divided into an anode chamber and a cathode chamber by laminating frame-shaped electrode gaskets constituting an anode chamber and a cathode chamber with a flat ion exchange membrane interposed therebetween. ,
The electrode chamber of the anode chamber or the cathode chamber and the manifold, which has an internal tube for supplying electrolyte therein and has an electrolyte circulation passage hole and an electrolyte supply passage hole at the bottom, are connected through the electrode gasket and the connecting tube. connected,
At least the connecting edge of the electrode gasket with the connecting pipe is formed of a hollow pipe, and one or more circular holes are formed on the inner peripheral surface of the connecting pipe on the connecting pipe side of the hollow pipe and on the peripheral surface on the electrode side, respectively. A hole is drilled to connect the electrode chamber and the manifold, connect an electrolyte supply pipe to the electrolyte supply passage hole, and pass through the connecting pipe and the hollow pipe to reach the lower part of the electrolyte chamber. 1. A filter press type ion exchange membrane method electrolytic cell, which is installed in a tank to supply and circulate an electrolytic solution.