JPH0230446Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention is a filter press type for seawater electrolysis that prevents calcium, magnesium, etc. in seawater from depositing on the cathode. Regarding electrolytic cells.

(Prior art) In an electrolytic cell for seawater electrolysis, precipitates such as magnesium hydroxide and calcium carbonate accumulate on the cathode plate and cause interelectrode blockage, resulting in a decrease in flow rate, an increase in cell voltage, and There was a problem in that the current efficiency decreased, and in order to remove the above-mentioned precipitates, the operation had to be frequently interrupted to carry out treatments such as backwashing and pickling.

In many conventional seawater electrolytic cells, electrolysis is performed by supplying seawater from below to an electrolytic cell that accommodates vertical electrodes. Therefore, it was inevitable that seawater would come into contact with the lower end corner of the cathode, and magnesium and calcium in the seawater would precipitate and accumulate.
To overcome this drawback, it has been proposed to make the lower end of the cathode round or wedge-shaped to prevent the formation of precipitates (Utility Model Publication No. 54-143361).
Publication No.). Although this method can fairly effectively prevent the precipitation of magnesium and calcium in seawater, it may not be possible to completely prevent precipitation depending on the metal content of the seawater and the electrolysis time.

On the other hand, a seawater electrolytic cell consisting of horizontally stacked electrolytic chambers having an anode and a cathode is known (Japanese Patent Application Laid-Open No. 58-1999).
Publication No. 171587). However, in this electrolytic cell, no consideration is given to the precipitation of metals in seawater or the flow path of the electrolyte.

(Problem to be solved by the invention) The inventors of the present invention focused on the fact that metal is deposited on the cathode in conventional seawater electrolyzers because the electrolyte comes into contact with the lower end of the cathode. The present invention has been developed to have a structure in which the electrolyte solution does not come into contact with the lower end of the cathode, and the purpose of this invention is to prevent metals such as magnesium and calcium from being deposited on the cathode. be.

[Structure of the idea]

This invention consists of a plurality of unit electrolytic chambers having vertical anodes and cathodes stacked horizontally via spacers, and each unit electrolytic chamber has an electrolyte inlet at the bottom of one end and an electrolyte inlet at the top of the other end. A filter press type electrolytic cell for seawater electrolysis, in which each spacer is provided with a communication passage connecting the electrolytic solution outlet of a unit electrolytic cell and the electrolytic solution inlet of an adjacent unit electrolytic cell. .

The present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings, but the present invention is not limited thereto.

FIG. 1 is a longitudinal sectional view showing an embodiment of a filter press type electrolytic cell for seawater electrolysis according to the present invention, and FIG. 2 is an exploded perspective view of the same.

The electrolytic cell 1 includes a pair of left and right end frames 2,
2', and four unit electrolytic chambers 4 stacked laterally with three spacers 3 interposed between both end frames 2, 2'. Each unit electrolysis chamber 4
is a plate-shaped anode 5 and 1 present on both sides of the anode 5.
A pair of plate-shaped anodes 6, 6', the anode 5 and the anode 6,
6', cathodes 6, 6', and four gaskets 7 held between the spacer 3, and the outermost cathodes 6, 6' are in contact with the end frames 2, 2', respectively. An electrolyte supply port 8 is provided facing outward in the lower part of the end frame 2 on the left side of FIG. 1, and an electrolyte solution outlet 9 is provided facing outward in the upper part of the end frame 2' on the right side. There is. Of the pair of anodes 6, 6' of each unit electrolytic cell 4, an electrolyte inlet 10 is bored at a location corresponding to the electrolyte supply port 8 at the bottom of the left cathode 6, and the right cathode 6' An electrolyte outlet 11 is provided at a location corresponding to the electrolyte outlet 9 in the upper part of the electrolyte outlet. Further, in the upper and lower portions of the anode 5, at locations corresponding to the electrolyte solution inlet 10 and the electrolyte solution outlet 11, there are lateral oblong holes 12.
are drilled in each. The spacer 3 that partitions each unit electrolytic chamber 4 has an oval upper flow hole 13 that aligns with the electrolyte outlet 11 of the cathode 6', and an oval lower flow hole 14 that aligns with the electrolyte inlet 10 of the cathode 6. is bored, and both communication holes 13 and 14 are communicated with each other by a communication path 15 that extends in the vertical direction. Each cathode 6, 6' is provided with one or two laterally directed projections 16, which are connected to the busbar 1.
7, it is connected to the projection 18 of the anode 5 of the adjacent unit electrolytic chamber 4.

Next, the procedure for seawater electrolysis using the apparatus of this embodiment will be explained.

When electricity is supplied from the anode 5 of the leftmost unit electrolytic chamber 4 and seawater is supplied as an electrolyte from the electrolyte supply port 8 into the electrolytic cell 1, the electrolyte flows between the anode 5 and the anode 5.
It is electrolyzed while rising between the cathode 6' that sandwiches the
The partially electrolyzed electrolyte is transferred to the electrolyte outlet 1 of the cathode 6'.
1 through the communication path 15 of the spacer 3, and from the electrolyte inlet 10 of the cathode 6 to the adjacent unit electrolytic chamber 4.
The electrolyte is then electrolyzed in the same manner, and is taken out of the electrolytic cell 1 from the electrolytic solution outlet 9 of the unit electrolytic chamber 4 at the right end. In this case, the current flows from the anode 5 of the leftmost unit electrolytic chamber 4 to the left and right cathodes 6, 6' that sandwich the anode 5, and further passes through the bus bar 17.
It flows to the anode 5 of the adjacent unit electrolytic chamber 4, and then similarly flows inside the electrolytic cell 1 to electrolyze the sodium chloride in the electrolytic solution to produce sodium hypochlorite.

In this embodiment, seawater, which is an electrolyte, is supplied from the side to the electrolytic cell 1, and the lower end of the cathode is held between gaskets 7.
There is no contact with the lower end corners of the cathodes 6, 6'.
Therefore, metals such as magnesium and calcium contained in seawater do not precipitate on the cathode. Moreover, since the electrolytic solution flows from the lower part to the upper part of the unit electrolytic chamber 4 as before, the electrolytic solution is sufficiently electrolyzed within the unit electrolytic chamber 4, and the electrolysis efficiency does not decrease.

(Example 1) One dimensionally stable anode with a length of 50 cm, a width of 25 cm, and a thickness of 3 mm, and a pair of stainless steel plate cathodes of the same shape,
A unit electrolytic chamber is constructed by stacking them through a frame-shaped gasket with a thickness of 3 mm, and a total of four unit electrolytic chambers are stacked through three spacers that form vertical communication passages. The electrolytic cell for seawater electrolysis shown in Fig. 2 was prepared.

While passing a current of 300A through this electrolytic cell, 900l/
When seawater was supplied and electrolyzed at hr, the effective chlorine concentration in the electrolytic solution after electrolysis was about 1600 mg/l, and the current efficiency was 85 to 94%.

After 9 months of operation, the electrolytic cell was disassembled and the inside was observed, but no precipitation of magnesium hydroxide, calcium hydroxide, etc. was observed on the reaction surface.

(Example 2) The sizes of the anode, cathode, and frame-shaped gasket are
An electrolytic cell was assembled under the same conditions as in Example 1, except that the size was 100 cm and the width was 50 cm, the thickness of the frame-shaped gasket was 2 mm, and the number of unit electrolytic chambers was two.

While passing a current of 1300A through this electrolytic cell,
When seawater was supplied and electrolyzed at a rate of 3200 l/hr, the effective chlorine concentration in the electrolytic solution after electrolysis was approximately 1000 mg/l, and the current efficiency was 85 to 95%.

After 8 months of operation, the inside was inspected, but no precipitates were found on the reaction surface.

[Effect of idea]

In this invention, the electrolytic solution supplied into the electrolytic cell is
The structure is such that the metal in the electrolytic solution does not come into contact with the corners of the electrode where it is likely to be deposited, and the electrolytic solution itself flows from the bottom to the top within the unit electrolytic chamber as before. Therefore, according to the device of the present invention, seawater can be electrolyzed with conventional efficiency without depositing metal compounds or the like on the electrode reaction surface.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a filter press type electrolytic cell for seawater electrolysis according to the present invention, and FIG. 2 is an exploded perspective view of the same. 1... Electrolytic cell, 2, 2'... End frame,
3... Spacer, 4... Unit electrolytic chamber, 5... Anode, 6, 6'... Cathode, 10... Electrolyte inlet, 1
1... Electrolyte outlet, 15... Communication path.

Claims (1)

[Scope of utility model registration request] A plurality of unit electrolytic chambers having vertical anodes and cathodes are stacked horizontally via spacers, and each unit electrolytic chamber has an electrolyte inlet at the bottom of one end and an electrolyte outlet at the top of the other end. A filter press type electrolytic cell for seawater electrolysis, characterized in that each spacer is provided with a communication passage connecting the electrolytic solution outlet of a unit electrolytic cell and the electrolytic solution inlet of an adjacent unit electrolytic cell.