JPS599186A - Electrolytic cell of vertical cell and electrolyzing method - Google Patents

Abstract

PURPOSE:To expell quickly cathodic gas and to decrease electrolytic voltage in the stage of electrolyzing an aq. soln. of an alkali halide metal by an electrolytic cell of an ion exchange membrane method by using a non-porous cathode plate. CONSTITUTION:A generation chamber 7a for cathodic gas wherein the a cation exchange membrane 4 and a cathode plate 1 is spaced as narrow as <=2mm. and a non- porous cathode manufactured of Fe, Ni, etc. is used for the cathode 1 in an electrolytic cell of an ion exchange membrane type for an aq. soln. of an alkali halide metal such as NaCl. The cathode gas of hydrogen or the like generated on the surface 1a of the cathode 1 facing to the membrane 4 is like small foam, ascends quickly in the chamber 7a; at the same time, the electrolyte ascends as well and both enter through an opening 2 into the gas sepn. chamber 7b on the opposite side of the plate 1. The gas is discharged through an outlet 11, and the electrolyte enters the chamber 7a through an opening 3 and circulates. Since the gas foam in the electrolyte is quickly moved upward and separated, the electric resistance of the electrolyte is small and electrolysis is accomplished with high power efficiency by the reduced voltage during the electrolysis.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel electrolytic cell divided into a cathode chamber and a cathode chamber by an ion exchange membrane, and an electrolysis method. More specifically,
Negative (the cargo compartment is separated by a gas generation chamber and gas compartment I by a non-porous cathode plate)
By generating a circulating flow due to the gas rifling effect in the electrolytic cell divided into an IF chamber, a gas generation chamber, and a gas distribution chamber, the shaving gas generated on the cathode plate is substantially completely removed. Concerning a method of electrolyzing from the sinus.

Conventionally, for example, in electrolytic cells in which aqueous halogenated alkali solutions are electrolyzed using a cation exchange membrane, porous cathodes have been used most often. Metal sheets or wire mesh are typical.

When performing electrolysis using such a porous cathode, part of the cathode gas generated on the surface of the cathode rises between the cation exchange membrane and the cathode, and the other part rises from the pores to the cathode. Pass through the back and rise.

By the way, the presence of cathode gas generated in the anion or the cathode retreat, particularly between the cathode and the cation exchange membrane, leads to an increase in liquid resistance, resulting in an increase in the electrolytic pressure.

As a method for preventing gas bubbles from accumulating in the shade of birch, for example, Japanese Patent Application Laid-Open No. 52-1z571 uses an expanded metal for the cathode, and the axis of the opening is vertical/3 directions and a specific 61 degree angle ( 0 to 45 degrees) is disclosed. However, even if this method is used, the rough cutting between the anode and the negative surface with the cation exchange membrane sandwiched is about 2 mm, or especially about I
When Inm becomes 'T', the cathode gas remains in the minute gap formed between the negative electrode 17m and the membrane, and the electrolytic voltage increases as shown in FIG.

In order to solve this problem, Japanese Patent Application Laid-open No. 53-56193,
No. 53-46483 and No. 53-814988 disclose a method in which a flow path partition plate is installed behind the electrode and electrolysis is performed while generating i-waste reflux or forcibly generated by forced circulation, and A liquid supply port is installed in the 7F electrode chamber using pump pressure to generate a downward flow, and the cathode gas generated in the porous cathode is extracted from the bottom of the partition wall to the back of the partition wall instead of being extracted behind the cathode. An electrolytic cell has been proposed in which a porous electrode having horizontal bars with an upward slope toward the surface of the cell and the diaphragm is used to allow a liquid flow to flow from behind the electrode to generate a circulating flow. However, even if these proposed techniques are used, if electrolysis is carried out at a distance of about 2 am or less between the anode and cathode with an ion exchange membrane interposed therebetween, or especially about 1 mm or less, circulation will occur in the minute gap between the cathode and the membrane. The effect of removing bubbles (gas) by the flow becomes difficult to achieve, and therefore, the circulating flow is guided only to the rear of the porous cathode, and a large amount of bubbles accumulates between the membrane and the cathode. For this reason, the amount of bubbles attached to the membrane and electrodes inevitably increases, resulting in a voltage rise curve as shown in FIG.

As a method to solve these problems, JP-A-57-2
No. 3076 discloses that a gas and liquid permeable conductive 1'L porous layer is arranged on the surface of the membrane to prevent gas from entering the membrane. are taught how to do so. However, with this method, it is difficult to apply it to large-scale electrolyzers such as industrial electrolyzers (used for cars). Forming layers is never easy.

Not only -1-Kiwaki 1rlV? [No results can be expected from the problem of rapidly removing the gas on the extreme surface.

Furthermore, JP-A-56-! According to Publication No. 1.16891,
Prevents gas from adhering to the membrane by roughening the surface of the membrane.1
1. However, the same problems as mentioned above remain with the hydraulic method.

In view of the above circumstances, the inventors of the present invention have arrived at the present invention as a result of intensive investigation in an attempt to solve the problems of these conventional techniques.

That is, the first aspect of the present invention is that an electrolytic cell is divided into an anode chamber and a negative electrode chamber by an ion exchange membrane. The content of the electrolytic cell is characterized in that the electrolytic cell is connected by an opening 1-1 provided in substantially the most part and the most part, and the electrolytic cell is characterized in that the electrolytic cell is Divided into U and Yin (゛), the cathode is surrounded by the ion exchange membrane of the non-porous cathode plate and the side wall of the cathode chamber frame. A gas generation chamber and No. 1
When electrolyzing the electrolyte using an electrolytic cell divided into two parts, gas generation chamber is generated in the gas separation chamber surrounded by the back of the porous fJtg negative plate and the cathode chamber frame. Due to the gas lift effect of the cathode gas, a flow is caused in the catholyte, and the cathode gas and catholyte are mixed into the gas distribution chamber 1 through the opening 11, which is also provided at the top of the cathode. The cathode gas is separated from the catholyte in the gas separation chamber, and the liquid in the gas separation chamber is made smaller than the mixed flow in the gas generation chamber. ] By introducing and flowing the gas into the gas generation chamber again through the opening 1.1 provided in a part, a negative 1!il is introduced into the cathode gas generation chamber and the gas separation chamber.
The electrolytic JJ method is characterized by generating (16 reflux) through some open parts.

The features of the present invention are as follows: First, in the non-porous IY 11°C 1□ (in the minute gap between the handle and the ion exchange membrane, all the myopic gas generated in the pupil is directed only in the 1-yi force direction). , by generating a high-speed 1xfi flow, air bubbles on the cathode surface and membrane surface are quickly removed, and from the 14 part opening 1 part the back of the non-porous + <1 negative M plate [it was shattered gas separation chamber Then, the l'AC'i' (air bubbles are separated between the plate and the ion exchange membrane in a gas separation chamber from 1 part to 11 parts)) containing ( An electrolytic film with a small I rate f〈 is supplied.The cross-sectional area perpendicular to the membrane of the gas portion Hill chamber can be the gas portion #t゛1 min + 1r-Vi, and the gas-containing T-i:' 713 with small r<: IQ
It has been decided that the 11th edition of the JkV division will be able to supply the complete version.

That is, it is desirable that the cross section of the gas chamber 1411 (at least gas generation) 1: the cross section of the chamber be approximately twice L-1°, vf or yarn -J5 times commi. ·Power,
Although there is no particular limitation regarding the amount of water, for example, increasing the white product by more than 500 times or more than 1000 times may have disadvantages such as increasing the installation cost of electrolytic T'F+. It is best to take these disadvantages into consideration when making a decision. Thus, according to the present invention, there is no stagnation of cathode gas, there is no accumulation of gas on the surface of the cathode and membrane, and the advantage is that the degregnating L1- is always low and the electric power consumption can be made small. .Furthermore, it is similar to expanded metal sheet.

When a porous cathode is used, the part of the membrane close to the metal part has a high electric density, and the part of the membrane that is in contact with the void part has a low electric density, and the microcurrent (11 is non-uniform) Therefore, the electrolytic voltage is 1.5%. However, since the cathode in the present invention is a non-porous material, there are no voids in the %qB itself, and therefore, a uniform current distribution can be obtained. The current +li is also uniform, and a low electrolytic voltage can be obtained, which is extremely advantageous.

Next, embodiments of the present invention will be described in detail based on the attached drawings.

In the explanation below, the electrolysis of chlorinated triunium and water bath liquid will be taken as an example, but it goes without saying that the present invention is not limited to these. It can be immediately applied to electrolysis accompanied by gas generation.

Furthermore, the present invention can also be applied to bipolar or single-pole filter press type electrolyzers and box type electrolyzers.

FIG. 2 is a schematic vertical cross-sectional view of the cathode chamber according to the present invention, and FIG. 3 is a cross-sectional view taken along the line AA in FIG.

In FIG. 2, the cathode chamber is surrounded by a non-porous cathode plate 1, a cation exchange membrane 4, a side wall of the cathode chamber frame (not shown), and a surface H+ of the cathode plate 1 facing the membrane 4. It is divided into two parts: a gas generation chamber 72] and a gas #I chamber 7b formed by the back surface 1b of the cathode plate 1, the cathode chamber frame 5 and the same side wall (not shown), The painting room is -1 of the Yinyuan board 1
Due to the opening 2.3 provided in the part and part 1.
It has been contacted.

Examples of cation exchange membranes suitable for the present invention include membranes made of perfluorocarbon polymers having cation exchange groups.

A membrane made of a perfluorocarbon polymer having a total exchange group of sulfonic acid groups was manufactured by E.I.Teubon Te Nimores An1-Company (pj,j',1) II in the United States.
11"(L(iernl1l(11l"TH&,C
It is commercially available from 0fT A (JJl, Y) under the trade name (Nafuigin 1), and its chemical composition (1 to 1) is as shown in the following formula.

The appropriate θf of such a cation exchange membrane is fdl, 00
0 to total 2,000, preferably I, 100 to 1°50
0, where the equivalent weight is the weight (g) of the dry film per exchange weight. In addition, the present invention also applies to cation exchange membranes in which part or all of the sulfonic acid and 11 (f?' of the exchange membrane 1) is replaced with a carboxylic acid group and other commonly used cation exchange membranes. These cation exchange membranes have extremely low water permeability and only allow 3 to 4 water molecules to pass through the thorium ions without allowing any hydraulic flow to pass through.

The non-porous outer surface (a curved surface with a value of 1, that is, the surface la facing the cation exchange membrane 4 is substantially flat).

The non-porous cathode plate 1 is preferably made of stainless steel or nickel, and the front surface of the cathode non-porous plate made of these materials is coated with platinum group metals, conductive oxides thereof, etc. in order to reduce the hydrogen overvoltage. It is more preferable to apply a coating of oxtails, buttons, group metals, etc. Fourth, the back surface of the non-porous cathode plate, that is, the surface 1b that does not face the cation exchange membrane, can be lined with rubber or heat-resistant plastic, or nickel-plated, in order to prevent corrosion by the cathode. , nickel spraying, etc. can also be suitably applied.

The distance between the non-porous cathode plate 1 and the cation exchange membrane 4 is not particularly limited, but is preferably about 5 mm or less, particularly about 2πm or more. The narrower the distance between the two, the more high-speed upward flow can be generated.

In the gas generation chamber 7F3, the negative gas generated on the front surface 1a of the cathode plate 1 forms a mixed flow with the nearby '1E solution, and becomes a high-speed laminar flow due to the so-called gas reflux 1-effect, and flows into the L section. The overflowing gas-liquid multiphase flow is separated from the gas and liquid at the gas opening (Figure 7) and falls as an electrolyte with a low gas content. Part 1 3
The gas is supplied to the gas generation chamber 7+-i. In addition, if necessary, forced circulation using a bomb etc. can also be suitably applied to the present invention. That is, "the electrolytic solution is forcibly sent from the part 11 part 3 to the gas generation chamber 7ε], and the electrolyte is forced into the gas generation chamber 72].
It is possible to accelerate the upward flow velocity at . The shapes of the upper and lower openings 2.3 are not particularly limited, and examples thereof include a horizontal tanzag shape and a shape in which round holes are arranged horizontally in a row. still,
Non-porous raw cathode plate 1 has a gas lift effect. - As long as it does not slow down or disturb the eyebrow flow, minute holes and slits 1
-1 The double-edged edge of the cathode plate A1 - The clearance may include a slight gap etc. that occurs at the part. History of cathode gas generation of non-porous VL cathode plate according to the present invention/'', Uside surface iF]
For example, it is sufficient to have a cathode plate made by thermally spraying N1 powder of about 10 μm, which can be viewed macroscopically as a flat surface, and which has convex grooves in the direction of the straight force when it is broken. It may have a structure. It may have small protrusions at appropriate intervals.

The uneven structure can be obtained by, for example, scraping out parallel miso on a flat plate, attaching a thin rod-shaped body such as a round bar or a square stick to the flat plate by welding, or by integrally kneading it. It is also possible to make a pupil plate using corrugated plate. The waveform has no particular control waveform, and is rectangular waveform.
A vertical shape, a sinusoidal shape, a circular shape, a cycloidal shape, etc. can be used alone or in combination. Further, the unevenness does not necessarily have to be continuous in the vertical direction, and may be broken in the middle. When using a non-porous cathode plate having an uneven structure, it is a preferred embodiment that the protrusions and the ion exchange membrane are adjacent to or in contact with each other. In this case, the convex stripes function as a kind of kite rail when the cathode gas rises.

The liquid level in the gas chamber 7b may be lower than the upper opening 2, or may be higher than the upper opening without any problem.

Removal of the cathode gas and electrolyte can be carried out using conventional techniques.

The anode serving as the counter electrode of the non-porous cathode plate 1 is a conventionally used anode, i.e., an expanded metal sheet made of a valve metal such as titanium, niobium, or tal, or an expanded metal sheet made of an alloy thereof, or a conductive oxide thereof, or a conductive oxide thereof. A material coated with a reducing oxide or the like can be used. Furthermore, an anode of the present invention having a structure in which a plate made of a non-porous valve metal is coated with the above coating can also be suitably used.

FIG. 4 is a schematic diagram of an electrolyte illustrating an example of an embodiment of the present invention. FIG. 5 is a sectional view taken along line B-B.

The cation exchange membrane 4 is tightly fitted between the electrode chamber frames 5 and 18 by a corrosion-resistant gasket 15, and a cathode chamber 7 and an anode chamber 17 are formed via the protective membrane 4. The non-porous cathode plate 10 and the porous anode 16 are fixed by conductive rods 6 and 8 so as to face each other with the cation exchange membrane 4 sandwiched between them.

Thus, the aqueous sodium chloride solution is supplied from the inlet 10 and electrolyzed by the anode 6, and the generated chlorine gas is taken out from the outlet 14.

On the other hand, the electrolyzed dilute anolyte is taken out from the outlet 12. On the other hand, water strainer or a dilute caustic soda aqueous solution is introduced into the cathode chamber 7 through the inlet 9, and the niJ
Then, it is electrolyzed on the first side B, and hydrogen gas is generated. departure 41
Raw gas is taken out from outlet 1113, and concentrated caustic soda is taken out from outlet 11.

Although the present invention has been described in detail in accordance with the illustrated embodiments, it is not limited thereto, and many modifications can be made by those skilled in the art without departing from the spirit and spirit of the present invention. It goes without saying that there is nothing that can be done,
Variations thereof are also within the scope of the present invention.

Example 1 DuPont's "Nafion 9" was used as a cation exchange membrane.
011 was used, and an electrolytic vessel having an effective electrolytic surface IQOmmXt1 700 mm was used. As a non-porous raw cathode, S1. A flat plate of JS304 (7) with a thickness of amm was used. The front surface of the cathode is coated with nickel particles.
・One low hydrogen overvoltage was used. The distance between the back surface of the cathode and the C chamber plate was 30 mm. The anode is a solid solution of titanium oxidized metal, ruthenium oxide, and titanium oxide? Ju overturned was used.

The distance between the membrane and the cathode plate was set to 5 mm, and the membrane and anode were set so that they were in contact with each other, and while supplying 5N lNace aqueous solution to the anode chamber and water to the cathode chamber, the sodium chloride concentration in the anode chamber was increased to 3 mm.
Electrolysis was carried out at 80° C. while maintaining the caustic soda solution at 32 mm% and the following results were obtained.

The caustic current efficiency was 96% at a current density of 30 A/dm2 and a voltage of 3.09 V. Furthermore, 1 at 235△/(u)f
The electrolysis continued, but the cell voltage remained constant.

Example 2 The distance between the back side of the non-porous negative milking board and the electric milking chamber is set to 1mm, 5mm, 15mm, and 7mm. Electrolysis was carried out in the same manner as in Example 1 except that ff and kaibaku were set respectively. The electrolytic voltages are 8.65V, 3, and 14V, respectively.
It was 3.09\l.

Comparative Example 1 Electrolysis was performed in the same manner as in Example 1, with the lower opening sealed, and the current density was 3.8 at a current density of 23.5 Ay·+m'.
A result of 5V was obtained.

Comparative Example 2 Electrolysis was carried out in the same manner as in Example 1, except that an iron Exband 1 metal (minor diameter 3 mm, major diameter 8 mm) subjected to low hydrogen overvoltage treatment was used as the cathode plate.

Current density 23.5A, 3.17\'(17]l',
The result of I? ! )Ta.

[Brief explanation of drawings]

Figure 1 shows the relationship between pole distance and voltage.
3 is a schematic vertical cross-sectional view showing an example of the pupil chamber of the present invention, FIG. 3 is a cross-sectional view taken along the second line A-A, and FIG. , FIG. 5 is a sectional view taken along line B-B in FIG. 4. l... Non-porous cathode plate 2... Upper opening 3... Lower opening 4... Membrane 5... Cathode chamber frame 6... Conductive rod 7... Cathode chamber 7...・Gas generation chamber 1)...Gas separation chamber 8...Conductive rod 9...Catholyte inlet 10...Anolyte inlet 11...Catholyte outlet 12...
・Anolyte outlet 13...Cathode gas outlet 14...Anode gas outlet 15...Gas 'rtsu!・16...Porous hole 1 Shoyoan 17...Yang (1υ(chamber 18...Yang 1i < chamber frame 1st
Figure 13 1bA, J'=,, -15 ゛ro 52 ゛ro 5th [t8'ぢ5 . 4. Kana, 7. I3

Claims (1)

[Claims] ■ In an electrolytic cell divided into a positive electrode chamber and a cathode chamber by an ion exchange membrane, the cathode chamber is divided into two chambers, a negative electrode gas generation chamber and a gas separation chamber, by a non-porous negative electrode. A vertical electrolytic cell characterized in that the two chambers are separated and communicated by openings provided substantially at the top and bottom of the shade plate. 2. The electrolytic cell according to claim 1, wherein the non-porous cathode plate is made of an alkali-resistant material. 3. The electrolytic cell according to claim 1, in which an alkali-resistant material is corrugated on the back surface of the non-porous cathode plate. 4. The electrolytic cell according to claim 1, wherein the surface of the cathode gas generation chamber side of the non-porous chamber cathode plate is coated with a material having a low hydrogen overvoltage. 5. The electrolytic cell according to claim 1, wherein the surface of the non-porous cathode plate facing the cathode gas generation chamber is macroscopically flat. 6. The electrolytic cell according to claim 1, wherein the surface of the non-porous cathode plate on the cathode gas generation chamber side has an uneven shape with longitudinal convex striations. 7. Claim 6, in which a thin bar-like body made of a round bar, square bar, etc. is fixed to or protrudes from the body of a plate having a macroscopically V-shaped convex striation in the longitudinal direction. Electrolytic cell described in section. 8. The electrolytic cell according to claim 6, wherein the uneven shape having longitudinal convex striations is wavy. Claim 8, wherein the nine waveforms are any one of rectangular, trapezoidal, sinusoidal, circular, and cycloidal, or a combination thereof, or a waveform obtained by partially deforming these waveforms. The electrolyzer of war. The electrolytic cell according to claim 6, wherein the tip of the IO longitudinal convex stripes is in contact with the ion exchange membrane. Cathode gas generation is divided into a cathode chamber and a cathode chamber by a pressure ion exchange membrane, and the cathode chamber is surrounded by the surface of the non-porous cathode plate facing the ion exchange membrane, the ion exchange membrane and the side wall of the cathode chamber frame. When electrolyzing an electrolyte using a vertical electrolytic cell divided into two chambers: a chamber and a gas separation chamber surrounded by the back surface of the temporary non-porous cathode and a cathode chamber frame, the cathode gas generation The gas lift effect of the cathode gas generated in the chamber causes an upward flow in the cathode armpit, and a mixed flow of cathode gas and catholyte is guided into the gas separation chamber through an opening provided at the top of the cathode plate, thereby forming a gas separation chamber. The cathode gas is separated from the catholyte, and the catholyte in the gas separation chamber, which has a lower bubble content than the mixed flow in the gas generation chamber, is reintroduced into the gas generation chamber through an opening provided at the bottom of the cathode plate. An electrolytic method characterized by generating a circulating flow in a cathode gas generation chamber and a gas separation chamber through open portions above and below the cathode by stirring the cathode.