JPS5831894Y2 - Conductive pin for filter press type electrolytic cell - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a conductive pin for a filter press type electrolytic cell suitable for performing seal welding between the titanium lining and the conductive pin of a partition wall having a titanium lining on the inner surface of the anode chamber.

In recent years, cations have been developed that use resins made from fluorinated or fluorine-substituted vinyl compound monomers as a base material and have ion exchange groups such as sulfonic acid or carboxylic acid added to the side chain via perfluorovinyl ether. Exchange membranes were developed.

For this reason, in the field of producing chlorine and caustic alkali by electrolyzing aqueous alkali chloride solutions, ion-exchange membrane method is used as an electrolysis method to correct the drawbacks of water pollution, air pollution, and low energy efficiency of the conventional mercury method and diaphragm method. is being developed.

Conventionally, cation exchange membranes have had to be made thinner in order to simplify manufacturing, ease of handling, and lower electrical resistance as much as possible.

For this reason, ion exchange membranes have hitherto been provided in the form of sheets, and in particular, fluorine-based cation exchange membranes such as those mentioned above are mostly in the form of sheets.

There are two types of electrolytic cells that perform electrolytic operations using such sheet-like cation exchange membranes: finger-type electrolytic cells in which the cation exchange membrane is processed into a bag shape and installed, and electrode chambers formed by the outer frame. There is a filter press type electrolytic cell in which a cation exchange membrane is placed between hollowed out plates and assembled using a pressure wave method.

Finger-type electrolytic cells have the advantage of being able to use conventional diaphragm-type electrolytic cells as is, but the technology to process them into a bag shape has not yet been perfected, and the mechanically complex surface along the electrode fingers needs to be sealed. However, it has not been put into practical use because it is very difficult to do so and the electrode chamber liquid tends to leak easily.

On the other hand, the filter press type electrolytic cell has the following advantages: (1) The electrolytic cell is compact, so the factory site area is small; (2)
It is very easy to assemble by sandwiching the sheet-like cation exchange membrane, and (3) the electrode chamber frame and the external sealing surface of the cation exchange membrane have a simple structure, so there is little leakage of the electrode chamber liquid. (4) In addition, it has many advantages, such as the fact that leaks can be detected quickly and countermeasures can be easily taken.

The general characteristics of such a filter press type electrolytic cell have been known for a long time, and a fluorine-based cation exchange membrane was developed for alkaline chloride electrolysis and applied as an electrolytic cell type, but the electrode chamber frame material.

There were many imperfections in the structure of the power supply section, and it was not possible to guarantee satisfactory operation as an electrolytic cell.

As the material of the electrode chamber frame has a galvanic protection effect on the cathode chamber side, there is no need to use special materials if care is taken to prevent leakage current, but the anode chamber is exposed to oxidation conditions, so special care must be taken. It is necessary and a lot of effort is being made.

For example, attempts have been made to use polypropylene filled with asbestos, mica, calcium silicate, talc, etc., and oxidation-resistant plastics such as vinyl chloride and Teflon as electrode chamber frames; methods for lining electrode chamber frame structural members such as iron; Efforts have been made to develop methods such as forming the bottom of the mold.

However, since plastic has a large elongation at an electrolysis temperature of 80 to 100° C., the former peels and cracks due to the difference in elongation with the electrode chamber frame structural member, and does not have a sufficient life as a commercial electrolytic cell.

In addition, in order to satisfy the mechanical strength of the latter, the thickness of the frame portion and the partition wall portion is thick, which tends to cause distortion and leakage of the polar chamber liquid.

This becomes an even more serious problem especially when the size of the commercial electrolyzer increases.

It is necessary to use oxidation-resistant metal as the material constituting the electrode chamber frame.

Valve metals such as titanium, zirconium, tantalum, tungsten, and niobium are commonly used as metals for this oxidation-resistant material, but titanium is particularly expensive, but it is used in the electrode chamber frame of commercial electrolyzers. It is suitable as a material constituting the.

When titanium is used as a material for forming the electrode chamber frame of commercial electrolyzers,
It has been considered to make the anode chamber frame only from titanium, but titanium is expensive, and in order to provide sufficient mechanical strength for a large electrolytic cell, a large amount of even more expensive titanium must be used. The production costs were high.

For this reason, a common method is to provide expensive titanium with only chemical corrosion resistance, and compensate for mechanical strength, which is a problem when increasing size, by using inexpensive metal structural materials such as iron, which does not have chemical durability. has been adopted.

These methods include using steel or titanium clad plates for the frame of the unit electrode chamber frame and partition walls, using iron or titanium clad plates for part of the partition walls, and lining titanium plates on the iron partition walls.

However, these methods have the following obstacles and problems.

In other words, the method of using steel or titanium clad frames for the unit electrode chamber frame and partition walls requires advanced technology to manufacture the clad plates, and there are problems with adhesion, and explosive cladding causes noise during manufacture. Chirasu.

The method of using iron or titanium cladding for part of the bulkhead is a cost reduction method compared to the method of cladding the entire surface.
This does not solve other essential problems, and new problems such as the uniformity of the cladding portion and a decrease in the strength of the iron partition wall arise.

The method of lining steel bulkheads with titanium plates does not require very advanced technology, so it has the advantage of being cheaper than the method of using clad plates, but it takes time and effort to fix the lining, and the lining tends to float. It has the following disadvantages.

On the other hand, the structure of the power supply part and the power supply method are important factors to sufficiently guarantee the operation of the electrolytic cell.

For this reason, an external power feeding method, as typified by JP-A No. 51-72973, is proposed, in which a power feeding part extending from the electrode surface is brought out outside the electrode chamber frame and connected to a power supply or another power feeding part, and Japanese Patent Publication No. 53-558
A screw-in method for sealing the power supply part that penetrates the polar chamber frame, such as No.
A clad plate bulkhead method is adopted in which an iron or titanium clad plate bulkhead as typified by No. 32880 is used as the main power supply part, and electricity is supplied to the electrodes by ribs serving as auxiliary power feed parts extending from the bulkhead.

However, with the external power supply method, the power supply part becomes a shield inside the electrode chamber, creating a dead space, which accelerates the deterioration of the performance of the cation exchange membrane, and makes it difficult to seal with the outside, causing liquid leakage.
Furthermore, when setting the electrodes, the electrode surfaces may shift, damaging the cation exchange membrane or making it impossible to maintain an appropriate distance between the electrodes.

In addition, with the screw-in method, the power supply part generates heat during electrolysis and reaches a high temperature, so special care is required for the packing, which may last several months to a year.
The gaskets must be replaced every year, and electrode sets require a lot of work, requiring a large number of maintenance personnel.

The clad plate partition system has problems such as it takes time and effort to weld the auxiliary power supply part to the clad plate, and the auxiliary power supply part acts as a shield inside the electrode chamber, and countermeasures and improvements to these problems are desired.

The object of the present invention is to provide a conductive pin for a filter press type electrolytic cell that does not require advanced and complicated technology and allows effective use of expensive titanium.

The present invention maximizes the performance of the cation exchange membrane and ultimately provides an electrolytic cell having a simple structure and a maintenance-free power supply section.

The present invention uses the minimum amount of titanium as a lining material for a filter press type electrolytic cell, avoids any inconvenience during construction, and provides a highly reliable structure for the power supply part of the electrolytic cell. It has been discovered that by doing so, all of the above objectives can be met and the drawbacks of the conventional methods can be solved at once.

That is, in the present invention, in order to properly perform seal welding between the titanium lining and the conductive pin of the partition wall in which the titanium lining is provided on the inside of the anode chamber, the conductive portion substantially made of titanium on the anode side is connected to the anode. A conductive pin for a filter press type electrolytic cell has a shape cut to a thickness equal to or more than the thickness of the titanium lining of a partition wall whose interior surface is lined with titanium.

Conventionally, when applying titanium as a lining material, plug lining method and strip lining method are known, but these methods expose titanium plates to high temperatures when TIG welding, so it is difficult to use titanium plates with a thickness of 3 m/m or less. If the thickness is too thick, there will be problems such as melting, blow holes in the welded parts of the lining, and loss of corrosion resistance of titanium, making it impossible to continue functioning as an electrolytic cell for a long period of time.

According to the present invention, a titanium plate having a thickness of 3 m/m or less and about 0.2 m/m can be used without causing the above-mentioned problems, and the economical effect is extremely large.

In particular, in the electrolysis process where a cation exchange membrane is attached to a filter press type electrolytic cell, the area of the cation exchange membrane and the lining area of the unit multi-chamber frame partition are equal, so the effect is large and the chlorine and caustic The production cost of alkali can be significantly reduced.

According to the present invention, since the conductive pin (power feeding part) becomes a fixed part of the lining, the lining does not float, and heat generated by resistance loss in the conductive pin is quickly transmitted to the lining part, so the lining has a fin effect. This increases heat dissipation and eliminates the risk of overheating.

As described above, the filter press type electrolytic cell conductive pin of the present invention can solve at once the problems that occur especially when increasing the size of the electrolytic cell.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a sectional view of a unit bipolar chamber frame of a filter press type electrolytic cell showing a typical embodiment used to electrolyze an aqueous alkali chloride solution using an ion exchange membrane using conductive pins of the present invention. be.

FIG. 2 is a partially enlarged sectional view taken along the line AA' in FIG. 1.

3 is a partial cutaway view of a large unit electrode chamber frame having the basic structure shown in FIG. 1, viewed from the anode side.

In FIG. 1, the unit bipolar chamber frame 3 forms an anode chamber space 1 and a cathode chamber space 2 by joining an iron frame 33 and an iron partition wall 32 by welding 36.

A titanium lining 31 is provided on the anode chamber side of the iron partition wall 32.

The iron used for the frame 3 and the partition wall 32 includes not only iron but also an alloy containing one or more of carbon, manganese, silica, nickel, chromium, molybdenum, etc.

In addition, the titanium 31 used for the lining is not only titanium metal but also includes titanium alloys containing palladium etc. JIS-TP 35, which maintains mechanical strength even when the lining is thinned to 1 m/m or less. is preferred.

The anode chamber space 1 and the cathode chamber space 2 are respectively provided with a supply nozzle 16 and a drain nozzle 17 for the anode chamber liquid, and a supply nozzle 26 and a drain nozzle 27 for the cathode chamber liquid. A cation exchange membrane 5 is sandwiched between an anode chamber packing 51 and a cathode chamber packing 52 in a filter press type.

In bipolar electrolytic cells, in order to prevent electrical short-circuiting between opposing unit electrode chamber frames due to bridges of alkali chloride, etc. that precipitate due to liquid leakage, a cation exchange membrane is placed on the outer layer of the electrode chamber frame as shown in Figure 1. It is preferable to make it protrude further.

The anode chamber space 1 is completely protected from the anode chamber liquid by the titanium lining 31 of the partition wall 32 and the flange lining 34 of the iron frame, and the anode 11 is accommodated therein.

Further, a cathode 21 is accommodated in the cathode chamber space 2, and the anode 11 and the cathode 21 are electrically connected by a conductive pin 4, which is a conductive portion.

In FIG. 2, the electricity collected on the cathode 21 is collected on the cathode dispersion plate 22, and then on the steel frame 43 of the conductive pin 4.

In this figure, the conductive pin 4 is connected to a titanium portion 41 via a substance 42 that prevents atomic hydrogen generated at the cathode from diffusing toward the anode, and electricity is transmitted to the titanium portion.

The material 42 includes chromium, molybutin, silver, copper, etc., and the means for constructing such a conductive pin include screws, screws, etc.
Examples include crimping, welding, cladding, etc.

Friction welding disclosed in JP-A-49-82588 and JP-A-51-11078 is a preferred means of implementation.

The conductive pin 4 thus constructed is welded 37 to the iron partition wall.
is fixed.

Although the conductive pin can be fixed to the partition wall with screws, the cathode chamber liquid leaks and enters between the partition wall and the titanium lining and corrodes the titanium, so it is preferable to completely seal it with welding 37. In general, a conductive part made of titanium is defined as a case where the entire conductive pin is made of titanium, as shown in Figure 4, or a case where the anode side of the conductive pin is made of titanium and the other parts are made of titanium, as shown in Figure 2. Regardless of the material it is made of, it basically refers to the part of the conductive pin on the titanium lining side of the partition wall in which the inner surface of the anode chamber is lined with titanium.

In FIG. 2, the titanium portion 41 of the conductive pin of the present invention is cut from the iron partition wall 32 to a thickness greater than the thickness of the titanium lining 31, and the titanium parts are welded together for sealing 35.

The current in the titanium portion passes through the welded portion 14 with the anode boss 15 and reaches the anode 11 through the anode boss, the anode conductive plate 13°, and the anode current distribution plate 12.

These anode constituent members are effective in uniformly distributing current to the anode 11 and in controlling the degree of parallelism of the anode to the cation exchange membrane.

In FIG. 2, a hole 19 is made in the anode for attaching the welding part 14, but it is preferable to close it after attaching it.

FIG. 6 shows a titanium lining method for a unit electrode chamber frame of a conventional filter press type electrolytic cell, and FIG. 7 shows a lining method for a filter press type electrolytic cell according to the present invention.

In FIG. 6, a titanium lining 101 having a thickness of hl is welded to a steel partition wall 102 by seal welding 10 with a titanium pin 104.
3 at a distance of hl from the iron partition wall 105.

In FIG. 7, a titanium lining 101 having a thickness of h2 is fixed to an iron partition wall 102 by a conductive pin 108 cut by a distance h3 by a seal weld 103 at a distance of h4+h3.

In FIG. 6, since the distance from the chain part is only the thickness of the titanium lining, the heat during seal welding is transmitted to the chain part, forming an alloy with titanium, significantly reducing corrosion resistance, and causing pinholes during electrolytic operation.

Especially when the thickness of the titanium lining is 3m/m or less,
Since the welding penetration spreads throughout the thickness, it is easy to form an alloy with iron, increasing the danger.

On the other hand, in Fig. 7 of the present invention, the distance from the chain part is more than twice that of the conventional one, so the heat of seal welding is not transmitted, and the heating part is covered with titanium, so the heat transfer Radiation increases, the chain part is not heated, and titanium and iron alloys are not generated.

This effect becomes even greater when the thickness of the titanium lining is reduced to 3 m/m or less, and even if the thickness of the titanium lining is 0.2 m/m and the melt penetration spreads over the entire thickness h4, the heat is transferred to the iron partition wall 105 due to the cut h3 portion. You can prevent it from being transmitted.

According to the present invention, since the conductive pin is welded to the titanium lining, even if the conductive pin generates heat due to resistance loss during electrolysis, the fin effect of the lining sufficiently precedes the residual heat and the temperature becomes almost the same as the electrolysis temperature. Unlike conventional conductive pins, there are no problems such as burning, and the product has a long life.

The cutting shape of the conductive pin of the present invention needs to be at least as thick as the titanium lining, but cutting too much is undesirable because it reduces the cross-sectional area of the conductive pin and increases resistance loss more than necessary. 100 times or less is better.

The cutting rate range is 3m/m, where the effect of this invention is remarkable.
When performing the following titanium lining, the value obtained by dividing the cutting distance h3 by the thickness h4 of the titanium lining is 1.1 to 2.
Preferably, it is 0.

In order to show the relationship between the conductive pin 41 and the anode 11, FIG. This is an example of a unit bipolar chamber frame of 1,200 m/m x 2,400 m/m with the pin spacing clearly indicated.

When performing such a wide lining, conventional technology requires that the pitch at which the lining is stopped is 250 m/m or less, but the present invention fixes the lining using the cut-shaped conductive pin portion. This shows that the floating of the lining is suppressed by the pitch of 600 m/m.

This reduces the number of seal welds at the fixed portion of the lining, which greatly contributes to shortening the process and reducing manufacturing costs.

Of course, the pitch of fixing the lining with conductive pins cannot be extreme; it should be determined based on the manufacturing process and allowable float, and is preferably 200 to 600 m.
/m.

FIG. 4 is an enlarged view of a conductive pin portion of a unit anode chamber frame of a filter press type electrolytic cell showing another embodiment of the present invention.

FIG. 5 is a partial cutaway view of a large unit anode chamber frame having the basic structure shown in FIG. 4, viewed from the anode side.

In FIG. 4, the titanium lining 81 on the iron partition wall, which is mechanically and electrically connected to the threaded part 83 of the iron partition wall 82 through the threaded part 92 to the titanium conductive pin 91, is formed by cutting the conductive pin of the present invention. It extends to the shaped portion 93 and is fixed by a conductive pin and seal welding 85.

An anode current distribution plate 6 to which an anode 61 is connected from the conductive pin
2 is growing.

Figure 5 shows a 1200 m x 2400 m grid with 7 rows of conductive pins to uniformly distribute the current to the anode.
This is an example of a unit anode chamber frame for /, and the current enters from a terminal 88 which is an extension of the partition wall.

The partition wall mixing hole 87 is used to equalize the electrolyte concentration in the two anode chambers separated by the partition wall.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a unit bipolar chamber frame of a filter press type electrolytic cell showing a typical embodiment using conductive pins used to electrolyze an aqueous alkali chloride solution using the ion exchange membrane of the present invention. be. FIG. 2 is a partially enlarged sectional view taken along the line AA' in FIG. 1. FIG. 3 is a partial cutaway diagram of a large unit electrode chamber frame having the basic structural diagram of FIG. 1. FIG. FIG. 4 is an enlarged view of the conductive pin portion of the unit anode chamber frame of the filter press type electrolytic cell. FIG. 5 is a partial diagram of a large unit anode chamber frame having the basic structure shown in FIG. 4. FIG. 6 is a diagram showing a titanium lining method for a unit electrode chamber frame of a conventional filter press type electrolytic cell. FIG. 7 is a diagram illustrating a method of lining a filter press type electrolytic cell according to the present invention. In the figure, 1-anode chamber space, 4,91.108-conductive pin,
5 Cation exchange membrane, 31.81.101-Titanium lining, 32.82,102-Iron partition, 33-Iron frame, 35,85,103-Titanium seal weld, 93
．． h3 - cutting shape part of conductive pin, 104 - titanium pin, h, h4 - thickness of titanium lining, respectively.

Claims (1)

[Scope of utility model registration request] A conductive pin for a filter press type electrolytic cell having a shape in which a conductive portion on the anode side substantially made of titanium is cut to a thickness equal to or more than the thickness of the titanium lining of a partition wall in which the inner surface of the anode chamber is lined with titanium.