JPS5928583A - Electrolytic tank - Google Patents

Abstract

PURPOSE:To reduce electrolytic power consumption and to enhance current efficiency, by a method wherein a cathode and an anode having an elastic structure is integrated with a cation exchange membrane and both electrodes are connected to the frames of each electrode chambers to specify the ratio of the gas contact part and the liquid contact part in each electrode chamber. CONSTITUTION:In an ion exchange membrane method applied filter press type electrolytic tank for the electrolysis of an aqueous alkali chloride solution, an anode 1 and a cathode 2 are formed into corrugated loopers with highly elastic structures to be respectively connected to conductive members 3, 4 and supported by support members 7, 8 to be integrated with a cation exchange membrane 6 in a substantially contact state by surface pressure. An anode frame 13 accommodating the anode 1 has a hole 9 for an anode liquid supply header, a hole 11 for supplying and dispersing the anode liquid, a hole 10 for an anode liquid gas exhaust header and a hole 12 for gathering and exhausting the anode liquid gas and the ratio of the gas contact part and the liquid contact part of the anode is brought to 0.05 or less. In addition, a similar structure is formed with respect to the cathode frame of the cathode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to an electrolytic cell for an aqueous cation exchange alkali chloride salt solution.

More specifically, in an electrolytic cell for an aqueous alkali chloride salt solution using a cation exchange method, an anode and a cathode are installed in a cation exchange membrane so that they are substantially closely integrated, reducing electrolytic power during electrolysis and improving current efficiency. Moreover, it is an object of the present invention to provide an electrolytic cell that can operate stably for a long period of time.

Conventional methods for electrolyzing an aqueous alkali chloride solution include a mercury electrolysis method that uses mercury at the cathode, and a diaphragm method that does not use mercury (asbestos diaphragm method).

In the mercury method, since mercury is used in the cathode, mercury is contained in the product caustic soda and in the wastewater that has come into contact with the mercury.Therefore, due to environmental pollution issues, non-mercury processes are being adopted worldwide. . In addition, the mercury method has poor power efficiency, with an average electrolytic power consumption of 200 KwVt/caustic soda.

In the asbestos diaphragm method, since mercury is not used, there is no problem of environmental pollution due to mercury, but the problem of environmental pollution due to asbestos remains.

In addition, the average electrolytic power unit is 2.500 xwH/l. Although the power efficiency is high with caustic soda, the concentration of the generated caustic soda is low at 10 to 12%, so it is difficult to concentrate it to 50%. Approximately Z5 t/ of caustic powder steam is required, which is worse than the water pot method in terms of overall energy efficiency.

On the other hand, in the ion exchange membrane method that uses a cation exchange membrane as a diaphragm, which has been developed and commercialized in recent years, neither mercury nor asbestos is used, so there is no problem of environmental pollution, and the concentration of caustic powder produced is 20 to 40. % and high (, the average electrolytic power consumption is 2,500 KWV't, caustic soda, 50%
Approximately 41/1 caustic soda vapor is required to concentrate up to 100%, but the overall energy efficiency is the best.

In order to further reduce the electrolytic power and maintain long-term stable operation in the cation exchange membrane method, the inventor of the present invention has conducted extensive studies and experiments, and as a result, has provided a cation exchange membrane that is closely integrated with the anode and cathode. In an electrolytic cell, the cation exchange membrane, anode, and cathode are not separated due to liquid pressure fluctuations, gas pressure fluctuations, liquid pressure differences, and gas pressure differences in the anode and cathode chambers (they are operated in a substantially integrated state). Invented an electrolytic cell that can

It has been found that by electrolyzing an aqueous alkali chloride salt solution using this electrolytic cell, it is possible to reduce the electrical M/sliding voltage without impairing the current efficiency, and at the same time, it is possible to operate stably for a long period of time.

Conventionally, a leaf spring was provided on the opposite side of the anode facing the cation exchange membrane to make it movable, and a leaf spring was provided on the opposite side of the cathode facing the cation exchange membrane to make it movable. A method of assembling an electrolytic cell by interposing a cation exchange membrane between these anodes and cathodes, and bringing the O7 electrode into close contact with the cation exchange membrane is described in a special article [5i1
It is shown. However, in this method, under the pressure difference due to pressure fluctuation liquid fluctuation, the contact pressure by the leaf spring is reduced to [LO
O3x10-f/ctn2~6 Q X i O-”
fh", it is not possible to obtain sufficiently stable adhesion, and the electrolytic voltage increases in the long term compared to the initial electrolytic voltage. It cannot be expected to be reduced.

The inventor of the present invention aims to always obtain stable adhesion by minimizing pressure fluctuations in the anode and cathode chambers, and by making the anode and cathode themselves extremely elastic structures. We have discovered a method to reduce cell voltage without reducing current efficiency, which is the original objective.

That is, in the 'rtt, M tank, which is divided into an anode chamber and a negative chamber by a cation exchange membrane, a method for reducing pressure fluctuations is to minimize fluctuations in the liquid level in the electrode chamber.

The volume of the gas in the electrode chamber changes greatly depending on the relationship between the discharge rate of generated gas and the discharge rate of the electrode chamber liquid, and this change appears as a waving phenomenon in the electrode chamber liquid level. Changes in the volume of the gas layer in the electrode chamber appear as pressure fluctuations, and during operation of the electrolytic cell, a change in differential pressure occurs between the pressure in the anode chamber and the pressure in the cathode chamber.

Due to the differential pressure, the anode, cation exchange membrane, and cathode are brought into contact with each other, and the cation exchange membrane is in contact with one electrode but separated from the other electrode, causing cation Air bubbles remain between the exchange membrane and the peeled electrode, causing TfU41! ! This results in an increase in voltage.

As a method to eliminate the above-mentioned inconvenient factors, the anode and cathode are firmly fixed, and the film surface has a density of 10 K9/(1n2~1
For high blood pressure such as 00Ky/crn2, there is a method to integrate the anode and cathode on both sides of the cation exchange membrane with VJ tape! It is disclosed in Samurai Kaisho 56-9381. However, when the electrode is tightly attached to the membrane at high blood pressure, separation of the cation exchange membrane and electrode due to pressure fluctuations within the polar chamber does not occur, but the cation exchange membrane The cation exchange membrane is damaged by the intrusion K, and even if the cell voltage reaches its initial purpose, the current efficiency is significantly reduced and the electrolytic power is ineffective.

According to the present invention, the above-mentioned problems are avoided (and stable current efficiency and target cell voltage can be achieved over a long period of time).

Although the reason is unknown, by making the ratio of the gas-contacting part to the liquid-contacting part of the electrode in the electrode chamber 005 or less, it is possible to achieve an extremely stable cation exchange membrane, cathode, and anode. This is a completed electrolytic cell that can be operated in a completely integrated state.

Further, for better understanding, details A' will be explained with reference to the accompanying drawings.

FIG. 1 is an explanatory cross-sectional view of an example of assembled anode chamber frame and cathode chamber frame of the present invention.

Reference numeral 1 uses a titanium anode whose surface is coated with metal such as ruthenium, platinum, iridium, palladium, or an oxide thereof. 2 uses a cathode made of nickel, stainless steel, or iron whose surface has been treated with nickel plating or nickel spraying. 3 is a conductive member that supplies electricity to the anode, and is made of copper having low electrical resistance.

4 is a conductive member that cuts off electricity from the cathode, and is made of copper, aluminum, or the like having low electrical resistance.

5 is a gasket made of a rubber material having alkali resistance and chlorine resistance.

Although the cross-sectional shape may be a flat gasket to ensure sufficient sealing performance, it is preferable to use a convex gasket or a concave gasket. Also, the thickness of the gasket is a factor that determines the electrode chamber size and should be 5 to 20%, but it should be 8 to 12'.
It is preferable to adopt X.

6 is a cation exchange membrane having a carboxylic acid group on the cathode side and a sulfonic acid group on the anode side.

Reference numeral 7 denotes a spring-shaped support member for supporting the anode having an extremely highly elastic structure. Any chlorine-resistant material can be used, but titanium springs are preferably used.

Reference numeral 8 denotes a spring-shaped support member for supporting the cathode having extremely high elasticity.

Any caustic-resistant material can be used, but nickel springs are preferably used.

E11 When assembling the electrolytic cell of the present invention, the electrolytic cell of the present invention is used for the following: end clamping frame (not described) / cathode gasket / end cathode chamber frame (not described) /
Cathode gasket / cation exchange membrane / anode gasket / anode chamber frame / anode gasket / cation exchange membrane / anode gasket / cation exchange membrane / cathode gasket / cathode chamber frame / cathode gasket / cation exchange membrane / old... /Cation exchange membrane/Anode gasket/Anode chamber frame/Anode gasket/@
The ion exchange membrane/cathode gasket/end cathode chamber frame (not shown)/LJ pole gasket/end clamping frame (not shown) are assembled in this order, and the tie rods (not shown) or hydraulic system (
(not specified).

By adjusting the oil pressure of the hydraulic system or the tightening pressure of the tie rod, the distance N11 between the protrusion of the titanium anode 1 and the cathode 2 can be changed from 0 to 3'X. . The distance between the protrusions can be selected depending on the properties of the cation exchange membrane.

In the case of a cation exchange membrane in which both surfaces of the cathode side and the anode side of the cation exchange membrane have been subjected to hydrophilic treatment by metal plating, blast treatment, application of a paste having ion exchange ability, etc., the content is preferably 0 to 1%. Furthermore, it is a particularly preferable embodiment to set it to 0 to 0.2X or less.

FIG. 2 is an explanatory front view of the anode chamber frame.

Reference numeral 1 denotes an anode having an extremely elastic structure, and the shape is a wave-shaped louver. The pitch of the waves can be 5-15%, preferably 7-9%. Further, the dimension of the uneven portion of the wave-shaped louver can be 6 to 10%, but preferably 4 to 6 mm. In addition, the width of the louver is selected depending on the properties of the cation exchange membrane, but if the positive 411 of cation exchange ++p,
It is preferable to set it to 6 to 4% if water is being treated.Also, the center line of the vertical cross section of the corrugated louver is curved convexly to the cation exchange llI41!11I,
Preferably, the radius of the curved portion is greater than or equal to the single wave louver tJ'J, the longitudinal dimension of the pole.

3 is an anode electric power supply member. 7 is an electrode support. 9 is a hole for an anolyte supply header, and 1o is a hole for an anolyte gas discharge header.

11 is a hole for anolyte supply and distribution, 12 is a hole for collecting and discharging anolyte gas, the upper end of the hole is aligned with the upper part of the electrode chamber, and the vertical dimension of the hole is 1/20 of the height of the electrolytic surface of the electrode chamber. It is. Reference numeral 13 designates this anode chamber frame, which is manufactured by punching out a titanium or alloy plate by pressing or the like.

The thickness of the titanium or titanium alloy plate used is 0.5 to 5%, preferably 1 to 2%. Further, the height of the electrolytic surface can be set to 100 to 1 sooz, but (t
In order to reduce the per-air resistance, it is preferable to set it to 200 to 400 volumes. The width of the electrolytic surface can be arbitrarily selected, and is preferably 600 to 1500%.

FIG. 5 is an explanatory front view of the cathode chamber frame.

2 is a cathode having an extremely elastic structure, and the shape is a wave-shaped louver. The pitch of the waves can be 5-15%, preferably 7-9%. Further, the size of the uneven portion of the corrugated louver can be 5 to 10%, but preferably 4 to 6'X. The width of the louver varies depending on the properties of the cation exchange membrane, but if the anode side, cathode side, or both electrode sides of the cation exchange membrane are subjected to some kind of hydrophilic treatment, it should be 73 to 4%. is preferred. Further, it is preferable that the center line of the vertical section of the corrugated louver is curved convexly toward the cation exchange membrane side, and the radius of the curved portion is equal to or larger than the longitudinal dimension of the single corrugated louver electrode.

4 is a cathode electrical cutoff member. 8 is an electrode zabot. 14 is a hole for a catholyte supply header, and 15 is a hole for a ladder to catholyte gas discharge.

16 is a hole for supplying and distributing catholyte, and 17 is a hole for collecting and discharging catholyte gas. This is number 1.

Reference numeral 18 designates this cathode chamber frame, which is manufactured by punching out a nickel, iron, or stainless steel Mj field plate by pressing or the like.

The thickness of the nickel, iron or stainless steel plate is 0.5-5
% is used, preferably 1 to 2%.

In addition, the height of the electrolytic m1 can be set to 100 to 15"00%, but in order to reduce the electrical resistance, it can be set to 200 to 40".
It is preferable to set it to 0%. The width of the electrolytic surface can be arbitrarily selected, and is preferably 600 to 1500%.

Next, embodiments of the present invention will be explained in more detail.
It goes without saying that the present invention is not limited to this explanation.

Example electrolytic surface J7 whose height is 300% 1 width is 1000%
(At 30 dJ, 180 O
An electrolytic cell of the present invention was assembled to which an amount of electricity A was applied.

The anode has an 8X pitch with a convex and concave dimension of 5%.

A corrugated louver with a width of s% and a thickness of 1'X was coated with ruthenium oxide on the A side.

The electrode support is made of titanium wire with an outer diameter of 1%.
0% coiled material was used.

The cathode has an 8% pitch of 5% between the convex and four parts, and a width of 3'.
/¥n, 1% thick corrugated louver was used.

A nickel wire with a diameter of 1% and a coiled shape with an outer diameter of 10% was used as the electrode support.

Gaskets made of 12% natural rubber were used on both the anode and cathode sides to assemble the electrolytic cell. In addition, the cation exchange membrane is a fluorine-based membrane (about 20 mm thick) that has carboxylic acid groups on the cathode side and sulfonic acid groups on the anode side.
0μ) was used.

In both the anode chamber and the cathode chamber, the upper ends of the holes for collecting and discharging liquid gas in the electrode chambers were aligned with the upper part of the electrode chambers, and the dimensions of the holes in the height direction were set to 15%. The distance □ between the anode and cathode after the battery case is assembled is substantially the thickness of the film, and the anode and the film, and the cathode and the film are always tightly integrated.

The anode chamber frame of the above electrolytic cell was saturated at 62.21/H.
"Saline solution was supplied, and the current density was 30 A/dm while circulating caustic soda at 111.81/H in the cathode chamber."

Caustic sorter: Concentration 32w%, operating temperature 60F1 at 90℃
As a result of repeated operation, the following stable values were obtained.

tlL angle 1'Ft Soak voltage 150V Current efficiency (Naon standard) 95.5% Comparative example 1 Using the same electrode as in the example, the upper end of the hole for collecting and discharging liquid gas in both the anode chamber and the cathode chamber was The height dimension of the hole was 30'X to match the upper part of the electrode chamber.

After assembly, the anode and cathode were placed in close contact with each other in the same position as in the example. As a result of operating under the same operating conditions as in the example, the following initial values were obtained.

Electrolysis voltage 155V Current efficiency (NaO) i standard) 95.0% Comparative Example 2 Continuous operation for 30 days under the same conditions as Comparative Example 1 resulted in the following values.

It is clear from the examples that the electrolytic cell of the present invention greatly contributes to the reduction of electrolytic power, as shown in the electrolysis voltage: 550V'+ [f, flow rate (NaOH standard): 94.0%. Further, although the present invention has been explained using a monopolar electrolysis method, it can also be applied to a bipolar electrolysis method.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view of the assembled electrolytic cell of the present invention. 2 and 3 are front explanatory views of the anode chamber frame and the cathode chamber frame of the electrolytic cell of the present invention. 1 Anode 2 Cathode 5.4 Supply/discharge electrically conductive member 5 Gasket 6 Cation y exchange j]:'S 7.8 Electrode sabote member 15.18 Pole chamber frame patent applicant Toyo Soda Kogyo Co., Ltd.

Claims (2)

[Claims] (1) In an ion exchange membrane method filter press type electrolytic cell for an aqueous alkali chloride salt solution, the anode chamber in which the anode is installed and the cathode chamber in which the cathode is installed are separated by a cation conversion membrane. When electrolyzing an aqueous alkali chloride solution with both cathode electrodes substantially in contact and integrated due to blood pressure, an anode and a cathode having an elastic structure are installed, the electrode is electrically connected to the electrode chamber frame, and the electrode A 1L disassembly tank characterized in that the ratio of the gas-contacted part to the liquid-contacted part in the electrode chamber is Q,05 or less. (2) The electrolytic cell according to claim (1), wherein the electrode having an elastic structure is curved in a vertical section, and the radius thereof is equal to or larger than the longitudinal dimension of the electrode.