JPS5920756B2 - Diaphragm type electrolytic cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diaphragm type electrolytic cell for electrolyzing alkali metal halides.

Diaphragm electrolysers have been widely used for many years as electrolysers for the production of chlorine, caustic and hydrogen.

Over the years, these electrolytic cells have been improved successively, and it has become possible to obtain high operating efficiency based on the electrical energy consumed, but it is still not sufficient, and in recent years, the production capacity of individual cells has been increased. Many developments are currently underway. Most of these conventional electrolytic cells have a structure in which only the cathode porous plate or mesh body forming the electrolytic surface is used as a direct conductor.
For this reason, the current distribution and the concentration distribution of the electrode chamber liquid cannot be sufficiently uniformized, and furthermore, it is inconvenient to assemble and disassemble the diaphragm and the electrodes.

In the present invention, a plurality of cathode conductors are surrounded by a conductive porous plate or a mesh body to form a cathode chamber inside to form a unit cathode, and a plurality of these conductors form a cathode chamber.
It eliminates the drawbacks of the conventional electrolytic cell, makes it easy to replace the electrolytic diaphragm and cathode, has high current efficiency, and is extremely efficient with good convection in the anode chamber of the aqueous alkali metal/logenide solution. A diaphragm type electrolytic cell is provided.

That is, the present invention provides a diaphragm type electrolytic cell in which a cathode chamber and an anode chamber are formed by interposing a diaphragm between cathode and anode electrodes arranged alternately in parallel, in which a conductive bottom plate of the electrolytic cell is placed at a constant distance from each other. By providing a group of conductors standing upright in parallel in each row, and using the conductor group in each row as a support, a conductive perforated plate or net-like material is attached to the conductor group in contact with it, enclosing each row. A unit cathode is formed with the cathode chamber as a cathode chamber, and a common cathode chamber is formed at the lower part of the electrolytic cell to communicate the cathode chamber liquids of these unit cathode groups arranged in parallel, and the upper end is connected to the cathode chamber of each of the unit cathodes. Each unit cathode has a built-in hydrogen outflow tube that opens above the liquid level and into a hydrogen outflow groove whose lower end is isolated in the common cathode chamber, and furthermore, one end is fixed to the side wall of the electrolytic cell and the other end is placed opposite. An anode supported by a support rod fixed to the side wall of the electrolytic cell is installed between each unit cathode, and there is a gap sufficient for convection of the electrolyte between the side wall on the side where the support rod is attached and the ends of the anode and negative electrodes. A diaphragm type electrolytic cell characterized by the presence of.

'', and the present invention will be described in detail below with reference to the drawings. The present invention is a diaphragm type electrolytic cell having a combination of a cathode structure and an anode structure having a specific structure, and first, the cathode structure has a structure as shown in FIGS. 1 to 3.

That is, a conductive cathode bottom plate 1 having a cathode busbar attachment part 4;
Perforated plates or net-like plates 1' are formed above the bottom plate 1 at regular intervals, and bottom plates 1VC of the box 8 in which both are connected by four peripheral walls are formed at regular intervals through the perforated plates or net-like plates 1'. A large number of conductors 2 are provided that stand upright in parallel, and each row of these conductors is used as a support, and a conductive perforated plate or net-like body 3 is attached to each row, preferably by welding, to enclose them all at once. As a result, a large number of unit cathodes 5 each having a cathode chamber inside are arranged in parallel to each other to form a unit cathode group, and the opening at the bottom of each of these unit cathode groups is located at the bottom of the electrolytic cell. A common cathode chamber 8 (designated with the same drawing number as box 8 for convenience) is communicated with the box.

The square 18 is a diaphragm attached to the surface of the unit cathode 5 and the perforated plate or mesh plate 1'. Further, inside the cathode chamber 5 of each unit cathode (for convenience, the same drawing number as the unit cathode) is provided with a hydrogen outflow tube 6 whose upper end is opened above the cathode liquid surface. As shown in the figure, the lower end opens into a hydrogen outflow groove 7 provided separately inside the common cathode chamber 8, and the hydrogen generated in each cathode chamber by the electrolytic reaction is transferred to the hydrogen outflow groove 7 through a hydrogen outflow pipe 6. The hydrogen is collected and taken out of the tank through a hydrogen outlet pipe 9Vc shown in FIG. The configuration of the hydrogen outflow groove shown in Figure 4 is shown below.

The hydrogen outflow groove is formed by the side wall of the box 8, the side wall of a flat plate facing parallel to the side wall of the box with an interval that allows the hydrogen outflow pipe 6 to be inserted, and the cathode bottom plate, and furthermore, the hydrogen outflow groove is formed by the side wall of the box 8, the side wall of a flat plate facing parallel to the side wall of the box with an interval that allows the hydrogen outflow tube 6 to be inserted, and the cathode bottom plate. In order to prevent liquid from entering, the box 8 is closed by a flat plate provided below a perforated plate or a mesh plate provided above the box 8. Therefore, the hydrogen gas generated from each unit cathode body is collected in the outflow groove 7 through the hydrogen outflow pipe 6 and then discharged to the outside. As shown in FIGS. 5 and 6, in the - direction anode chamber, an anode fixture 17 having a bus bar attachment part 10 is attached to one side wall of the electrolytic cell body 12 formed by the four peripheral walls, and a large number of anode fixtures 17 are attached to this side wall. One end of the anode 11 is fixed, and the other end of the anode 11 is fixed by an anode fixing rod fixture 15VC fixed to the opposite side wall.

These anodes are spaced apart from each other so that they can be inserted and arranged parallel to each other between the unit cathodes of the cathode structure, and are mounted facing each other with a predetermined space between each unit cathode. Diaphragm 1
8, an F diaphragm such as an asbestos diaphragm or a dense diaphragm such as an ion exchange membrane is attached in contact between each anode and the unit cathode, preferably along the outer surface of the unit cathode and the surface of the perforated plate or mesh plate 1', and the electrolysis is carried out. By installing the tank lid 14,
The electrolytic cell is constituted by a cathode chamber formed by a cathode chamber inside each unit cathode 5 and a common cathode chamber 8, and an anode 1 via a diaphragm.
The part containing 1 becomes the anode chamber.

In addition, 13 is a packing for improving the tension of the electrolytic cell lid 14, 20 is an outlet for the cathode chamber product liquid produced by electrolysis, 21 is a supply liquid inlet to the anode chamber, and 2
2 is an outlet for gas (for example, chlorine gas) generated in the anode chamber. In the electrolytic cell using the cathode structure and the anode structure of the present invention as described above, the cathode bottom plate 1 is made of a material that is conductive and has high alkali resistance, such as iron, stainless steel, or a cladding of iron and copper. It is preferable that the upper surface is flat.

The conductor is fixed upright to this bottom plate, but the method of fixing is not particularly limited; for example, welding to the cathode bottom plate, bolting, fitting, soldering, etc. may be used, but bolting and fitting methods are acceptable. When adopting such a device, sufficient consideration must be given to ensure that the catholyte does not leak from that part. As mentioned above, a conductive perforated plate or net-like body is attached to the conductor in contact with the conductor, and if the material is a good conductive material and the same metal as the bottom plate mentioned above is used. good.

Furthermore, similar metals are used for the conductor material, but in terms of electrical resistance, alkali resistance, economic efficiency, etc., it is better to use a copper-iron clad product with a copper interior and iron exterior. is preferred. Furthermore, the spacing between each conductor used in a unit cathode is not particularly limited, but if it is too wide, the electrical resistance will increase and the power efficiency will be reduced, and if it is too narrow, a large amount of material will be used for the conductor, which is uneconomical. This will not only affect the permeation of the electrolyte, but also the permeation of the electrolyte. A cathode structure having a unit cathode having such a structure can greatly reduce electrical resistance compared to a conventional cathode in which only a conductive perforated plate or a mesh body is used as a conductor. Further, in the present invention, a hydrogen outflow tube is erected inside the unit cathode, and the upper end of the tube is placed above the liquid level of the electrolytically produced liquid, for example, the liquid in the cathode chamber which is mainly composed of caustic soda generated during electrolysis, and the lower end is placed inside the cathode chamber. The material of the hydrogen outflow pipe is not particularly limited, but high temperature resistant, alkali resistant resin, iron, stainless steel, etc. may be used. When using metal, care must be taken to avoid contact with the conductor and its surrounding body.

It is necessary that the hydrogen outflow groove provided in the cathode chamber be isolated from the cathode chamber, but as shown in FIG. A common cathode chamber for collecting the liquid and taking it out of the electrolytic cell is provided on the bottom plate of the electrolytic cell, and as shown in Figures 2 and 4.
As shown in the figure, if the hydrogen outflow grooves 7VC provided separately in this common cathode chamber are opened all at once and installed, the structure becomes simple.
Repairs are also easier.

Furthermore, as described above, the anode of the electrolytic cell of the present invention is mounted between each unit cathode with one end fixed to the side wall of the electrolytic cell and the other end supported by a support rod fixed to the opposite side surface of the electrolytic cell. be. Therefore, the gap between the side wall of the electrolytic cell and the negative and anode electrodes should be sufficient for convection of the electrolytic solution, and furthermore, if the saline solution flows into this gap, the diaphragm covering the unit cathode will not be damaged. Furthermore, it is convenient for attaching the anode to the electrolytic cell.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing a cathode structure of a diaphragm type electrolytic cell according to the present invention, and FIG. 2 is a vertical cross section of a unit cathode block and a common cathode chamber. Further, FIG. 3 shows a sectional view taken along line A-A' in FIG. or,
Fig. 4 is a perspective view showing the hydrogen outflow pipe and hydrogen outflow groove installed in the unit cathode, Fig. 5 is a perspective view of the assembled electrolytic cell, and Fig. 6 is a perspective view with the lid opened to show the inside of the electrolytic cell. It is a diagram. 1: Cathode bottom plate, ``: Perforated plate or mesh plate on top of box, 2: Conductor, 3: Perforated plate or mesh attached to the conductor, 4: Cathode busbar mounting part, 5: Unit cathode square and unit cathode. Chamber, 6: Hydrogen outflow pipe, 7: Hydrogen outflow groove, 8
：Box} and common cathode chamber, 9: Hydrogen outlet pipe, 10:
Anode busbar mounting part, 11: anode, 12: electrolytic cell body,
13: packing, 14: electrolytic tank lid, 15: anode fixing rod fixture, 16: gap, 17: anode fixture, 18: diaphragm,
19: Anolyte liquid level, 20: Outlet of cathode chamber generated liquid, 21
: Supply liquid inlet to the anode chamber, 22: Anode chamber generated gas outlet.

Claims (1)

[Claims] 1. In a diaphragm type electrolytic cell in which a cathode chamber and an anode chamber are formed by interposing a diaphragm between negative and anode electrodes arranged in parallel alternately, two electrodes are placed upright in parallel to each other at a constant distance from each other on the conductive bottom plate of the electrolytic cell. A unit cathode with a cathode chamber inside can be created by providing a conductor group in each row and using the conductor group in each row as a support and attaching a conductive perforated plate or net-like body in contact with it to surround each row. A common cathode chamber is formed at the lower part of the electrolytic cell to communicate the cathode chamber liquids of these unit cathode groups arranged in parallel, and the upper end is placed above the liquid level in the cathode chamber of each of the unit cathodes, and the lower end is Each unit cathode was equipped with a hydrogen outflow tube that opened into a hydrogen outflow groove provided separately in the common cathode chamber, and one end was fixed to the side wall of the electrolytic cell, and the other end was fixed to the opposite side wall of the electrolytic cell. An anode supported by a support rod is installed between each of the unit cathodes, and there is a sufficient gap for convection of the electrolyte between the side wall on the side where the support rod is attached and the ends of the negative and anode electrodes. A diaphragm type electrolytic cell.