JPS5920757B2 - Multipolar electrolyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a filter press type bipolar diaphragm electrolytic cell.

More specifically, in a filter press type bipolar diaphragm method electrolyzer, the electrolytic sliding voltage is reduced by bringing the anode and cathode as close to the diaphragm as possible, or by bringing them into substantial contact, thereby improving power efficiency. Along with letting. An object of the present invention is to provide an electrolytic cell that can greatly reduce the manufacturing cost of the electrolytic cell.

Traditionally, 6 electrolytic cells have been used to produce chlorine gas, caustic alkali, and hydrogen by electrolyzing an aqueous alkali chloride salt solution. It is also used to electrolyze water to produce oxygen and hydrogen.

Electrolysis methods for aqueous alkali chloride solutions include mercury electrolyzers that use mercury as a cathode and diaphragm electrolyzers that do not use mercury.

In mercury method electrolyzers, mercury is used in the cathode, so mercury is contained in the product caustic soda and in the waste water that has come into contact with the mercury. Due to the problem of environmental pollution, there is a trend around the world to adopt non-mercury processes.

In addition, in the 6-mercury method, the electrolytic power consumption per unit area is on average 3200KW1{
/t・Poor power efficiency due to caustic soda. Asbestos diaphragm electrolyzers do not use mercury, so there is no problem of environmental pollution caused by mercury. The problem of environmental pollution caused by asbestos remains. In addition, the average electrolytic power consumption is 25
00KW11/t caustic soda has high power efficiency, but the concentration of the generated caustic soda is low at 10-12%, so it takes about 2.5 t/t caustic soda steam to concentrate it to 650%. It is done. In terms of overall energy efficiency, it is worse than the mercury method. on the other hand. In the ion-exchange membrane electrolyzer, which uses a cation-exchange membrane as the diaphragm, which has been developed and commercialized in recent years. Since neither mercury nor asbestos is used, there is no problem of environmental pollution. The concentration of the caustic soda produced is also high at 20-40%. 6 The electrolysis power consumption is on average 2500
KWH/t・With caustic soda. Approximately 0.4 t/T° of caustic soda vapor is required to concentrate to 50%. Overall energy efficiency is the best.

The diaphragm method electrolytic cell includes a box-shaped monopolar cell type electrolytic cell as described in JP-A No. 51-63371 and 6 JP-A-52-6.
There is a bipolar electrolytic cell as described in 8075.
) 6 Small and medium-sized caustic powder manufacturing plants mainly use monopolar electrolytic cells, and large-scale plants mainly use bipolar electrolytic cells.

The reason for this is thought to be that bipolar electrolytic cells are more economical due to their larger current capacity than monopolar electrolytic cells. Also, for ion exchange membrane electrolyzers, JP-A-53-28
A monopolar electrolytic cell as described in 573 and JP-A-5
There is a bipolar electrolytic cell as described in No. 1-43377, in which six filter press types are adopted.

Unipolar electrolytic cells and bipolar electrolytic cells each have their own advantages and disadvantages, and the two-filter press type monopolar electrolytic cell allows you to freely select the current capacity according to the production scale. When converting, the substation equipment can be used as is. It also has the advantage that stable operation is possible with little fluctuation in production when the electrolytic cell is stopped or started for maintenance. On the other hand, the 6-filter press bipolar electrolytic cell has the advantage of being able to reduce the electrical resistance of the metal conductors between the unit electrolytic cells and reducing the power loss of the metal conductors. This method has the disadvantage that the production volume fluctuates greatly when the electrolytic cell is stopped or started for maintenance. Another drawback is that the manufacturing cost of the electrolytic cell is relatively high compared to a monopolar electrolytic cell. As a result of various studies and experiments to develop an energy-saving and low-cost electrolytic cell, the inventors of the present invention discovered that a filter press type bipolar electrolyzer in which a diaphragm is interposed between the anode and the cathode has been developed. In the tank. An anode-side conductive metal plate with a protrusion on the anode side that can withstand anodic electrolysis conditions, and a cathode-side conductive metal plate with a protrusion on the cathode side that can withstand cathode electrolysis conditions. By using electrically and mechanically bonded separators, the electrical resistance between the 6 units of electrolytic cells does not increase.
We have discovered an electrolytic cell that is inexpensive to produce. In addition, by adopting a suitably flexible wire mesh or mesh anode and/or cathode, the diaphragm and the anode and/or cathode can be brought into substantial contact, reducing the electrolytic sliding voltage. I found out that it can be done. That is. In a bipolar electrolytic cell that is divided into an anode chamber and a cathode chamber by a diaphragm, and each anode and cathode chamber has an anode and a cathode that are electrically connected to a separator, the separator has a protrusion that is resistant to anodic electrolysis conditions. A conductive metal plate on the anode side having a section and an electrically conductive metal plate on the anode side. A mechanically connected cathode consists of a cathode-side conductive metal plate having protrusions resistant to electrolytic conditions. Each anode and cathode are connected to a cathode-side conductive metal plate having protrusions that are resistant to electrolytic conditions. The gist of this invention is a bipolar electrolytic cell characterized by being electrically connected to a protrusion of a metal plate.

In the electrolytic cell of the present invention, the protrusions of the anode-side conductive metal plate and the cathode-side conductive metal plate may be provided at the same corresponding position, or may be provided at different positions. . Also 6
A reinforcing member can be provided on one or both of the protrusions. Also, by making this reinforcing member conductive. Mechanical relationship between the conductive metal plate on the anode side and the conductive metal plate on the cathode side. It can also be used for electrical connections. Generally, it is preferable to use a conductive connecting member to ensure electrical connection between the anode-side conductive metal plate and the cathode-side conductive metal plate.

This conductive connecting member can also be provided between the flat plate portions of both metal plates. Provided on the protruding part of the metal plate.
It is also possible to use this as a reinforcing member. The anode chamber frame and/or cathode chamber frame of such an electrolytic cell are manufactured in a free shape separately from the separator, and the manufacturing cost is 1/2 to 2 times that of conventional filter press type bipolar electrolysis. /3. Further, a clad plate made of titanium (or titanium alloy), copper, iron (or stainless steel) is used as the 6 conductive connecting member.
A flexible 6-wire mesh or mesh-like body can be used for the electrode. The distance between the electrodes (the distance between the anode and the cathode with the diaphragm narrowed) can be reduced to substantially the thickness of the diaphragm, and the electrolytic sliding voltage can be significantly reduced.

In order to further deepen the understanding of the present invention, the present invention will be explained with reference to the accompanying drawings, but the present invention is not limited to the drawings.

FIG. 1 is a plan view of the separator of the present invention, and FIG. 2 is a partially assembled view of the electrolytic cell of the present invention.

FIG. 3 is a sectional view of the separator of the present invention, and FIG. 4 is a sectional view of the attachment of the conductive member. 5 and 6 are drawings of the separator of the present invention in which the reinforcing member is omitted and the conductive connecting member also serves as the reinforcing member. 7 and 8 are cross-sectional views of the separator of the present invention when the protrusions of the anode-side conductive metal plate and the cathode-side conductive metal plate are arranged at different positions. In the description of the present invention based on the following drawings. As a preferred embodiment, a conductive connecting member is interposed between the anode side conductive metal plate and the cathode side conductive metal plate, but the anode side conductive metal plate and the cathode side conductive metal plate are connected without intervening a conductive connecting member. Needless to say, the present application also includes a case where the metal plate is directly connected to the metal plate by a known explosive crimping method or the like.

In FIG. 1, reference numeral 61 denotes a separator, which is composed of an anode-side conductive metal plate and a cathode-side conductive metal plate that can withstand the anode electrode solution.

4 or 5 is an anode or a cathode.

8 or 9 is a protrusion of the anode-side conductive metal plate or a cathode-side conductive metal plate.

Reference numeral 10 denotes conductive connecting members, the number of which is determined from the electrolytic surface (size of anode and cathode) and current density.

Reference numeral 11 denotes reinforcing members, which are provided in a number equal to the number of protrusions on the anode-side conductive metal plate or the total number of protrusions on the anode-side conductive metal plate and the number of protrusions on the cathode-side conductive metal plate.

In Figure 2, 64 is an anode. 5 is the cathode. 15 is a diaphragm.

Assembling the electrolytic cell consists of 6 electrolytic cell anode end plates (not shown)/
Gasket (not listed) / Anode chamber frame 16 / Gasket (
(No description) / Diaphragm 15 / Gasket (No description) / Cathode chamber frame 17 / Gasket (No description) / Separation plate 1 / Gasket (No description) / Anode chamber frame 16 / Gasket (No description) / Diaphragm 15 /...・・・・・・・・・/Cathode chamber frame 17/
Gasket (no description) / Separation plate 1 / Gasket (no description) / Anode chamber frame 16 / Gasket (no description) / Diaphragm 15 / Gasket (no description) / Cathode chamber frame 17 / Gasket (no description) / Electrolytic cell cathode Assembled in order of side end plates (not shown). The anode chamber frame 16 is made of metal. Alternatively, it is made of synthetic resin and is equipped with an anode electrolyte supply nozzle 18 and an anode electrolyte/gas discharge nozzle 19.

The cathode chamber frame 17 is made of metal or synthetic resin and includes six cathode electrolyte or water supply nozzles 20 and cathode electrolyte/gas discharge nozzles 21. In Figure 3, 6 separators 1
is composed of an anode-side conductive metal plate 2 having a protrusion 8 protruding toward the anode and a cathode-side conductive metal plate 3 having a protrusion 9 protruding toward the cathode.

A conductive connecting member 10 is electrically and mechanically attached between the flat part 6 of the anode-side conductive metal plate 2 and the flat part 7 of the cathode-side conductive metal plate 3 by resistance welding. Also, when the anode 4 and cathode 5 are attached between the protrusion 8 of the anode-side conductive metal plate 2 and the protrusion 9 of the cathode-side conductive metal plate 3 by resistance welding. If the respective protrusions 8 and 9 are deformed}, the reinforcing member 11 is attached. As the material of the anode-side conductive metal plate 2, metals such as titanium-6-tantalum and niobium, and alloy plates such as titanium-palladium alloy can be used.

The thickness of the metal plate is 0.1111! 1 to 5 m can be used, but preferably 0.1 to 2 m. Also, the height of the protrusion of the metal plate is 1! It7! L~5
It should be 0m71L. In order to make the rise of the anode electrolyte and gas smooth, it is preferably 51Em to 3Em.
It is 0mm. As the material of the cathode-side conductive metal plate 3, a metal such as iron or stainless steel, or a metal plate can be used. The thickness of the metal plate may be 1 mm to 10 mm, preferably 1 mm to 5 mm. Also, the height of the protrusion of the metal plate is 1! Although it can be set to 50 mm to 50 mm, it is preferably 5 m to 30 mm for manufacturing reasons and to ensure smooth rise of the catholyte and gas. The reinforcing member 11 is made of a rigid metal plate made of iron or stainless steel. The thickness used is 1 mm to 5 m71 L. The conductive connecting member 10 is a clad plate made of titanium (or titanium alloy) 12, copper 13, iron (or stainless steel) 14 as shown in FIG. and the plane portion 7 of the cathode-side conductive metal plate 3, and are electrically and mechanically connected using an electric resistance welder.

The thickness of the conductive connecting member 10 is preferably 61 m7 in order to reduce the electrical resistance of this part! L to 5 dragons are adopted, and the size depends on the magnitude of the current flowing through the connecting member. 1cr! i to 25 cd are used. The anode 4 is made of a known material such as a wire mesh made of titanium or titanium alloy or a valve metal made of expanded metal coated with oxide of ruthenium oxide and palladium hexaoxide, or coated with an alloy of platinum-iridium. used.

In addition, a flexible wire mesh or expanded metal is used for the flexible metal of the anode 4. 1-5j on the diaphragm side
By attaching the diaphragm so that it protrudes, the distance between the diaphragm and the anode can be reduced or the diaphragm and the anode can be substantially brought into contact with each other, thereby making it possible to reduce the electrolytic sliding voltage. For the cathode 5, iron or stainless steel wire mesh or expanded metal can be used. Furthermore, it is also possible to employ a cathode made of iron or stainless steel wire mesh or expanded metal with nickel plating applied to the surface.

In addition, a flexible wire mesh or expanded metal is used for the cathode 5, and the distance from the diaphragm side to 1j1 to 5m7! l By attaching it so that it sticks out. The distance between the diaphragm and the cathode can be reduced or the diaphragm and the cathode can be brought into substantial contact. In FIG. 5, the reinforcing member 11 in FIG. 3 is omitted. The conductive connecting member 10 also serves as a reinforcing member.

As shown in FIG. 6, the conductive connecting member which also serves as a reinforcing member is disposed between the protruding part 8 of the cathode-side conductive metal plate 2 and the protruding part 9 of the cathode-side conductive metal plate 3, and increases the electrical resistance. Electrical by welding. Mechanically connected. By doing so, the length of the path through which the current flows is shortened, so the electrical resistance is reduced. 7 and 8 show a state in which the protrusion 8 of the anode-side conductive metal plate 2 and the protrusion 9 of the cathode-side conductive metal plate 3 are arranged at different positions, and the anode 4 and/or Alternatively, the cathode 5 may be made of flexible wire mesh or expanded plastic. The top of the protruding part 8 of the anode-side conductive metal plate 2 and/or the protrusion part 9 of the cathode-side conductive metal plate 3 is 0 to 5 m.
7IL. Preferably, the diaphragm is narrowed by 0.511tm to 3mm and assembled so as to bite into the other electrode.
Complete contact between the anode and the diaphragm and between the cathode and the diaphragm can be achieved. Electrolytic sliding voltage can be significantly reduced.

Example 1 The height of the electrode is 1000 mm. A separator plate with a width of 500 mm as shown in Figure 3 was manufactured and an electrolytic cell was assembled.

The conductive metal plate on the anode side is 1m7 thick! With L's china board,
The height of the protrusion is 8 degrees and the base is 201 degrees! T7! Two rows of triangular protrusions are provided in the height direction of the separator.

The conductive metal plate on the cathode side is also an iron plate with a thickness of 1 inch, and the height of the protruding part is 8! ! Tm has a base of 20! Two rows of triangular protrusions of Nm were provided in the height direction of the separator. The conductive connecting member is a clad plate made of copper or iron, and the thickness of the chip is 0.5 m TIL. The thickness of copper is 1m7! L. The thickness of the iron was 1 mm, and the thickness of the 6-clad plate was 2.5 mm.

Also, the size of the clad board is 20 dragons x 20 I177! The size is 5 pieces, 4 pieces with a pitch of 200 m and 71 L in the height direction.
The rows were placed as close as possible to the protrusion and were electrically and mechanically connected by electrical resistance welding. The reinforcing member has a thickness of 5
mm. An iron plate with a height of 18.5 mm was used. The anode has a longitudinal opening dimension (LW) of 12.7rILm. An expanded mesh made by Chi-chan with a widthwise dimension (SW) of 6.3 mTI1 and a thickness of 1.57 mm coated with ruthenium oxide was used, and the anode was attached to the protrusion of the conductive metal plate on the anode side. At the top, a cathode was electrically and mechanically connected to the top of the protrusion of the conductive metal plate on the cathode side by electric resistance welding.

Using the separator to which the electrodes manufactured in this manner are attached, the electrolytic cell anode end plate (only the conductive metal plate on the anode side is attached) / gasket / anode chamber frame / gasket / cation exchange membrane / gasket are assembled. /Cathode chamber frame/Gasket/Separator/
Gasket/Anode chamber frame/Gasket/Cation exchange membrane/
The electrolytic cell was assembled by tightening the gasket/cathode chamber frame/gasket/electrolytic cell cathode side end plate (only the cathode side conductive metal plate was attached) with tie rods.

The gasket is made of natural rubber and has a diameter of 1mm. The anode chamber frame and cathode chamber frame are made of heat-resistant vinyl chloride and are 10m thick.
m, and the distance between the electrodes (the distance between the anode and the cathode when the diaphragm is narrowed) was approximately 4 mm. While supplying saturated saline at a rate of 15 t/h to each anode chamber of such an electrolytic cell and water at a rate of 1.6 t/h to each cathode chamber, the commercial flow density was 20 Vdm2,
The results of operation for 25 days at a caustic soda concentration of 35% and an operating temperature of 90°C were as follows.

Example 2 The height of the electrode is 1000 mm. A separator plate with a width of 500 mm as shown in FIG. 7 was manufactured and an electrolytic cell was assembled.

The anode side conductive metal plate and the cathode side conductive metal plate are Example 1
A similar device was used, but each protrusion was placed in a different position.

The protruding parts of the anode side conductive metal plate are provided in three rows in the height direction.6 The protruding parts of the cathode side conductive metal plate are provided in two rows in the height direction, and the same conductive connecting member as in Example 1 is used. 6200m
m pitch in six rows in the height direction, arranged at the center of the protrusion of the conductive metal plate on the anode side and the protrusion of the conductive metal plate on the cathode side. Mechanically attached by electrical resistance welding. Further, as for reinforcing members, iron plates with a thickness of 5 mm and a height of 10.5 mm were placed and attached to each protrusion. The anode has a longitudinal dimension (LW) of 5 mm and a width dimension (
SW) A 2.5 mm and 0.5 mm thick titanium expanded mesh coated with ruthenium oxide is used on the surface, and an iron expanded mesh with the same openings as the anode is used for the cathode. Six anodes were electrically and mechanically connected to the top of the protrusion of the conductive metal plate on the anode side and six cathodes to the top of the protrusion of the conductive metal plate on the cathode side by electric resistance welding.

Using the separator thus produced, an electrolytic cell was assembled in the same manner as in Example 1, and the anode chamber frame and cathode chamber frame were made of heat-resistant vinyl chloride, 7 mm thick, and conductive on the anode side. The protrusion of the metal plate digs into the cathode by approximately 0.6 mm, and the protrusion of the conductive metal plate on the cathode side bites into the anode almost 0.
．． It was 6mm.

The gasket at this time had a thickness of 1 mm and was made of natural rubber. Saturated salt water is supplied to each anode chamber of such an electrolytic cell at a rate of 15 t/h, and water is supplied to each cathode chamber at a rate of 1.6 t/h.
The results were as follows after 25 days of operation at a current density of 20 A//Dm, a caustic soda concentration of 35%, and an operating temperature of 90°C.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a separator used in the present invention. FIG. 2 is a partial assembly diagram of the electrolytic cell of the present invention. FIG. 3 is a sectional view of a separator used in the present invention. FIG. 4 is a sectional view showing the installation of the conductive member. FIG. 5 is a sectional view showing another embodiment of the separator used in the present invention.

Claims (1)

[Claims] 1. In a bipolar electrolytic cell that is divided into an anode chamber and a cathode chamber by a diaphragm, and each anode and cathode chamber has an anode and a cathode electrically connected to a separator, the separator is It consists of an anode-side conductive metal plate having a protrusion resistant to anodic electrolysis conditions and a cathode-side conductive metal plate electrically and mechanically connected to the anode side conductive metal plate having a protrusion resistant to cathode electrolysis conditions. A bipolar electrolytic cell characterized in that each of the cathodes is electrically connected to a protrusion of a conductive metal plate on the anode side and a protrusion of the conductive metal plate on the cathode side. 2. The bipolar electrolytic cell according to claim 1, wherein the protruding portion of the anode-side conductive metal plate and the protruding portion of the cathode-side conductive metal plate are provided at the same position. 3. Electrical and mechanical connection between the anode-side conductive metal plate and the cathode-side conductive metal plate is achieved by a conductive connecting member provided between the anode-side conductive metal plate and the cathode-side conductive metal plate. A bipolar electrolytic cell according to claim 1 or 2. 4. The bipolar electrolytic cell according to claim 3, wherein the conductive connecting member is provided between the protrusion of the anode-side conductive metal plate and the cathode-side conductive metal plate. 5. Claim 1 in which the protrusion of the anode-side conductive metal plate and the protrusion of the cathode-side conductive metal plate are provided at different positions.
bipolar electrolytic cell. 6 The electrical and mechanical connection between the anode-side conductive metal plate and the cathode-side conductive metal plate is established by a conductive connecting member provided between the anode-side conductive metal plate and the cathode-side conductive metal plate. A bipolar electrolytic cell according to claim 1 or 5. 7. The bipolar cell according to claim 6, wherein the conductive connecting member is provided on the protrusion of the anode-side conductive metal plate and/or the cathode-side conductive metal plate. 8. The bipolar electrolytic cell according to claim 2 or 5, wherein a reinforcing member is provided on the protrusion of the anode-side conductive metal plate and/or the cathode-side conductive metal plate. 9. The bipolar electrolytic cell according to any one of claims 1 to 8, wherein the anode-side conductive metal plate is made of titanium or an alloy of titanium and palladium. 10. The bipolar electrolytic cell according to any one of claims 1 to 8, wherein the anode side conductive metal plate is made of iron or stainless steel. 11. Claim 1, wherein the conductive connecting member is a clad plate composed of titanium-copper-iron, titanium palladium alloy-copper-iron, titanium-copper-stainless steel, or titanium palladium alloy-copper-stainless steel. A bipolar electrolytic cell according to any one of items 1 to 10. 12. The bipolar electrolytic cell according to any one of claims 1 to 11, wherein the diaphragm is an asbestos diaphragm or a synthetic diaphragm. 13. The bipolar electrolytic cell according to claim 12, wherein the synthetic diaphragm is a cation exchange membrane. 14. The bipolar electrolytic cell according to claim 1, wherein the anodic electrolysis conditions are based on an aqueous alkali chloride salt solution and/or an electrolyzed product thereof, and the cathodic electrolysis conditions are based on caustic alkali and/or hydrogen.