JPS59127378A - Leak current preventing method in electrode reaction equipment - Google Patents

Abstract

PURPOSE:To increase electric resistance in a passage and prevent leak current by mixing bubbles to a liquid in an electrolyte path connecting between cells. CONSTITUTION:An electrolytic bath is constructed with a positive chamber 1 and a negative chamber 2 which are stacked in series with a separator interposed, a main pipe 4 which supplies electrolyte 3 to the positive and negative chambers, and a branch pipe 12 and a branch pipe 5A which are branched from the main pipe 4. Bubbles are fed to the main pipe 4 in such a way that a gas supply pipe 8A which is connected to a gas cylinder 8 is inserted into a electrolyte path (main pipe) 4, or a set of electrodes 11 are faced in a path 10 of the electrolyte 3 and gas is directly generated and mixed to the electrolyte. The main pipe 4 is arranged above an electrolyte inlet of a unit cell. When electrolyte is supplied through U-shaped pipe which connects the main pipe 4 to the unit cell, bubbles are trapped with the U-shaped pipe to prevent entering to the unit cell.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing leakage current in an electrode reaction device, and more specifically to a structure in which an electrolytic solution is introduced from the outside into a positive electrode chamber and a negative electrode chamber, and flows out after an electrode reaction. The present invention relates to a method for preventing leakage current in an electrode reaction device such as a liquid flow type electrolytic cell or battery.

Conventionally, this type of electrode reaction device, as shown in FIG.
A single cell group in which a positive electrode chamber 1 and a negative electrode chamber 2 are stacked in series with a diaphragm in between, branch pipes 5A and 7A for allowing the liquid to flow out from the electrode chamber into the single cell group, and these. It is mainly composed of a main pipe 5 and a main pipe 5 to which are connected.

In the above-mentioned conventional device, when the electrolyte is fed into and out of each single cell column and 2 in parallel, the current flows through the diaphragm provided between the positive electrode chamber and the negative electrode chamber, and is consumed in the electrode reaction. However, in addition to this, there are also electrolyte flow paths connecting the positive electrode chamber and the negative electrode chamber, that is, main pipes 4, 6, 5 and 7, and branch pipe 4.
It also flows into the electrolytes in A, 6A, 5A, and 7A, and most of them flow out of the system and become leakage current. Such current is usually unrelated to the electrochemical reactions that occur within the positive and negative electrode chambers, and often results in power loss as it is.

The rate of such leakage current increases to 10 when the number of single cells is increased.
%, but it has been largely ignored in the past. As a countermeasure to this problem, attempts have been made to reduce the leakage current by increasing the length of the electrolyte flow path or decreasing its diameter to increase the electrical resistance at that portion. Therefore, with such measures, it is difficult to significantly reduce the leakage current, and when operating for a long period of time, the energy loss becomes enormous.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the prior art described above and to provide a method for effectively reducing leakage current in a simple manner.

In order to achieve the above object, the present inventors discovered that when air bubbles are mixed into the electrolyte flow path of an electrode reaction device, the electrical resistance within the flow path increases and leakage current is prevented. has been reached.

That is, the present invention provides an apparatus in which a plurality of single cells each having a positive electrode chamber and a negative electrode chamber are arranged via a diaphragm, and an electrolytic solution is passed through the cells to perform an electrode reaction. It is characterized by mixing gas and liquid into at least part of the liquid in the passage.

In the present invention, the smaller the bubbles and the larger the amount of bubbles generated in the electrolyte flow path, the stronger the effect of cutting off the electrolyte, and the more difficult it is for leakage current to flow. Furthermore, if the flow path is relatively small in diameter, it is also effective to cover the entire cross section of the flow path with a single bubble. The bubbles mixed into the electrolyte only need to be mixed in at least a part of the electrolyte flow path, and preferably the bubbles are generated or introduced from the inflow side of the electrolyte and allowed to exist for a long time in the subsequent flow path. preferable. In addition, in order to prevent air bubbles from entering the single cell, that is, the positive electrode chamber and the negative electrode chamber, the piping structure is designed to prevent air bubbles from entering the electrode chamber as much as possible by utilizing the difference in specific gravity between the electrolyte and the air bubbles, that is, the buoyancy of the air bubbles. It is preferable to do so.

One method of introducing bubbles in the present invention is to directly introduce gas into the electrolyte flow path using a compressor;
A method of supplying gas generated in an electrolytic tank for gas generation, a method of placing an electrode for gas generation directly in the electrolyte flow path to generate bubbles, a method of adding base metals to an aqueous electrolyte, etc. to generate hydrogen gas A method of mixing air bubbles using a chemical reaction such as generating , a method of using the vapor of the solvent itself as bubbles as in the electrolyte of high-temperature electrolysis, a method of sending a low-boiling point solvent into the electrolyte flow path A method is used in which a small capillary or the like is placed and the solvent is vaporized and introduced therein.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 2 shows an embodiment of the bubble introduction device used in the present invention, in which a gas introduction pipe 8A connected to a gas cylinder (for example, nitrogen gas) 8 is inserted into the electrolyte flow path (main pipe) 4. It is something. In this case, the structure is simple because it is only necessary to insert the gas introduction pipe 8A into the snow melt flow path 4, and there is an advantage that it can be provided at any location. In addition, the second
In the illustrated embodiment, when the inside of the electrolyte flow path (piping) 4 is in a reduced pressure state compared to the outside air, outside air may be mixed into the flow path through the regulating valve.

Next, FIG. 3 shows another embodiment of the present invention, in which when a single cell group is divided into an upper cell 92 and a lower cell 91, the lower cell 91 uses a side reaction etc. to perform the present invention. Sufficient gas is generated by electrolysis to carry out this process, and the generated gas is sent to the upper group of cells 92 through the connecting pipe 9A. In this embodiment, leakage current from the connecting pipe 9A onward is prevented, but
The generation of leakage current in the piping group of the T membrane cell 91 is unavoidable.

Furthermore, in the embodiment shown in FIG. 4, a pair of electrodes 11 are arranged to face each other in the flow path IQ of the electrolytic solution 3, and gas is directly generated here and mixed into the electrolytic solution. The embodiment described above can be easily implemented at low cost because it is sufficient to simply dispose the electrode in a protruding manner within the electrolyte flow path.

Further, FIG. 5 shows a preferred arrangement of electrolyte distribution piping in an electrolytic cell in which single cell groups are arranged in series. In the figure, this device consists of a positive electrode chamber 1 and a negative electrode chamber 2, which are stacked in series with a partition or a membrane in between, and the positive electrode chamber and the negative electrode chamber (
A main pipe 4 for feeding electrolyte 3 into the single cell, a U-shaped branch pipe 12 branching from the main pipe 4 and connected to the single cell, and a U-shaped branch pipe 12 provided upright above the single cell. Mainly composed of branch pipes 5A, main pipes 5 connected to these branch pipes, and a communication pipe 13 that bypasses the main pipe 4 on the inflow side and the main pipe 5 on the outlet side at one end of the single cell group. be done.

In this case, the main pipe 4 is arranged above the electrolyte inlet of the single cell, and when the liquid flows through the U-shaped pipe connecting the main pipe 4 and the single cell, air bubbles are trapped in the U-shaped pipe, It is designed not to enter a single cell. In other words, the difference in specific gravity between the electrolyte and the bubbles (the buoyancy of the bubbles) causes the bubbles to rise and separate while passing through the JUU tube and reaching the electrolyte inlet. Main pipe 4, connecting pipe 1
3 and the main pipe 5 on the outlet side to be discharged to the outside of the system. In this case, in order to enhance the current blocking effect, it is desirable to reduce the diameter of the portion 13A of the communication pipe 13.

According to the above embodiment, the main pipe 3 through which the electrolyte flows through the bubbles;
By mixing only the connecting pipe 13 and the main pipe 5, the stain flow blocking effect is greatly improved, and leakage current can be effectively prevented. Also, the air bubble is single cell 1-! Since it does not enter the tank 2, the operation of the electrolytic cell can also be stabilized.

In the above embodiments, the U-shaped tube 12 was used as a gas-liquid separation means between the main pipe 4 and the single cell 1 or 20, but other gas-liquid separation means, such as a liquid reservoir provided with a gas vent hole in the communication pipe 12A, were used. can be provided.

As described above, according to the present invention, leakage current in electrode reaction devices such as electrolytic layers and batteries can be effectively prevented, and energy saving of these devices can be achieved.

Examples and specific examples of the present invention will be described below.

Example A platinum mesh was placed at both ends of a polyvinyl chloride tube having a length of 1 m and an inner diameter of -1011111 mm, and the resistance between the platinum meshes was measured using an AC bridge method and a circuit tester.

A 1N sulfuric acid aqueous solution was flowed through the tube as an electrolyte at a flow rate of 100 d/min. Gas (air) shown in Figure 2
When bubbles were created in a polysulfuric acid aqueous solution using a method of introducing gas, the measured resistance value was about 50 times that before gas introduction. Next, when bubbles were created in the sulfuric acid aqueous solution using the electrolytic method shown in FIG. 4, the measured resistance value was about 30 times that before the gas was introduced. These results revealed that the electrical resistance of the electrolyte flow path increased significantly and was effective in reducing leakage current.

Example 1 An electrolytic cell consisting of 20 single cells having the electrolyte flow path shown in FIG. 5 was constructed, and electrolysis experiments using acidic hydrochloric acid, iron chloride, and aqueous solutions were conducted. Both positive and negative electrode liquids are 1N hydrochloric acid acidic 1 mol/2
25% of ferrous chloride and 1 mol/b ferric chloride aqueous solution
oMl is sent to the single cell group of this electrolytic cell at a flow rate of 1 minute, and 4
Electrolysis was performed at a constant current of A, and the proportions of divalent and trivalent iron in the electrolytic solution at the inlet and outlet of the electrolytic cell were measured by portammetry. Furthermore, no phenomena considered to be side reactions such as gas generation were observed during electrolysis. The ratio of the required current value calculated from the amount of current applied and the amount of iron subjected to electrolysis is approximately 1:0.97,
The leakage current flowing through the electrolyte channel was thought to be about 3%.

Next, during an electrolysis experiment under the same conditions, a nitrogen gas was introduced into the electrolytic tank inlet side flow path 4 for the positive and negative electrode liquids using a nitrogen cylinder. As a result, the leakage current was reduced to 0.5% or less.

In addition, as a method of generating gas by electrolysis, a platinum wire wound around the electrolyte flow path is placed as a cathode, while
A counter electrode chamber (anode chamber) was provided outside the electrolyte flow path via a diaphragm, and electricity was applied to generate hydrogen gas from the cathode. Iron (trivalent) itself and reaction with hydrogen gas and iron (trivalent) by platinum cathode
It was difficult to accurately detect the reduction in leakage current because it is thought that a reaction with As a result, it was found that at least the leakage current was 1% or less.

Example 2 A platinum mesh was placed at both ends of a resin tube having a length of ltn and an inner diameter of -Lo+tn++, and the resistance between the platinum meshes was measured using an AC bridge method and a circuit tester. The above tube contains 1 mol/1. sulfuric acid) IJ
Aqueous solution of aluminum was poured into the chamber at a flow rate of 100 mg/min. A nichrome wire was installed on the inlet side of the aqueous solution tube, and electricity was applied to partially boil the aqueous solution near the nichrome wire to create water vapor bubbles, which were mixed into the aqueous solution. The resistance between the platinum wire mesh after energizing the nichrome wire is approximately 20% compared to the value after energizing.
It was found that the resistance value doubled and the leakage current decreased significantly.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional electrode reaction device consisting of a group of single cells in which a positive electrode chamber and a negative electrode chamber are electrically stacked in series, and FIGS. 2, 3, and 4 are illustrations of the present invention, respectively. FIG. 5 is an explanatory diagram of an electrode reaction apparatus showing still another embodiment of the present invention. 1...Positive electrode chamber (single cell), 2...Negative electrode chamber (single cell), 3...Flow of electrolyte solution, 4...
... Electrolyte flow path, 8 ... Gas cylinder, 11 ...
...Gas generation electrode. Agent Patent Attorney Takeshi Kawakita

Claims (1)

[Scope of Claims] (1) In an apparatus in which a plurality of single cells each having a positive electrode chamber and a negative electrode chamber are arranged with a diaphragm interposed therebetween, and an electrolytic solution is caused to flow through the cells to perform an electrode reaction, a connection between the single cells is provided. 4? Is it possible to mix air bubbles into at least a part of the electrolyte liquid passage that communicates with it? A method for preventing leakage current in an electrode reaction device. (2. A method for preventing leakage current in an electrode reaction device according to claim 1, characterized in that the bubbles mixed into the electrolytic solution are generated by an electrolytic method. (3) Claim 1 2. A method for preventing leakage current in an electrode reaction device, which falls within the scope of item 1 and 2, and includes separating air bubbles at a cell inlet and mixing the air bubbles into an electrolyte passage so as to prevent air bubbles from entering the cell.