JP2010126769A - Composite electrolytic bath - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic bath which continuously produces a new material by electrolysis, and can reduce a ratio of a remaining unelectrolyzed substance while suppressing the production of by-product, without sacrificing production efficiency. <P>SOLUTION: In continuous electrolysis with the use of one unit of an electrolytic bath, only one type of the combination of voltage and current can be set in the electrolytic bath, and accordingly a substance to be electrolyzed can be electrolyzed only on an electrolytic condition corresponding to the average of the compositions of the substance to be electrolyzed in the inlet and outlet of the electrolytic bath at the most. Accordingly, in order to obtain an electrolytic condition which has further progressed than the outlet composition, there is no other method than that of using a plurality of electrolytic units in combination, in which an electrolytic condition can be set independently. Accordingly, an electrolytic bath which can reduce the ratio of the unelectrolyzed substance in the continuous electrolysis is the composite electrolytic bath that includes two or more of the electrolytic bathes 1 and 2, which are arranged so as to constitute flow channels 8 and 9 in a fixed direction of the substance to be electrolyzed, and in which at least voltages between counter electrodes in the respective electrolytic bathes are independently set. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a technique for continuous electrolysis in a composite electrolytic cell composed of a plurality of electrolytic cells in electrolysis of a substance.

Methods for producing substances by electrolysis (electrolysis) have been performed over a wide range of fields since ancient times. The main reasons are that electrolysis can proceed with low energy compared to means such as heating and pressurization, and that the reaction can be selected to some extent by selecting the electrolysis voltage. It is.

However, there are drawbacks in electrolysis, one of which is that the voltage and current values depend on the concentration of the electrolytic raw material (ion). Therefore, it means that the production purity and electrolysis efficiency depend on the raw material concentration. When performing continuous electrolysis, it is necessary to fix the current and voltage ranges to be constant in order to maintain the production efficiency of the substance, so electrolysis cannot be performed below the ion concentration where the lower limit condition of the set electrolysis cannot be maintained. . This means that a certain level of untreated substance is included in the raw material after the treatment, and depending on the purpose, a treatment step such as separation by physicochemical treatment may be required after the electrolysis. Also, if post-treatment itself is technically difficult or costly that is not suitable for practical use, the efficiency must be sacrificed by reducing the processing speed until the concentration of unelectrolytes is not problematic. It may not be possible.

On the other hand, in the case of batch electrolysis, the selection of electrolysis conditions and electrolysis time can be freely set, so this problem may be solved, but the production efficiency must be greatly sacrificed. Therefore, it is inevitable that the generation cost will rise significantly.

Therefore, various devices for advancing the electrolytic reaction have been made. Patent Document 1 describes a multistage electrolytic ionic water generator. It is said that a strongly acidic ionic water is efficiently generated by adding a halide to the acidic electrolytic ionic water produced in the first electrolytic cell, sending it to the electrolytic cell in the next stage, and performing electrolysis. On the other hand, Patent Document 2 describes a water treatment method and a processing apparatus in which a plurality of electrolytic cell units are accommodated in one electrolytic cell container. It is said that treated water having good properties can be obtained from the last electrolytic cell unit by transferring the internal liquid of the cylindrical electrolytic cell to the adjacent electrolytic cell units one after another and performing electrolysis.

Japanese Patent Laid-Open No. 7-3987 Japanese Patent Laid-Open No. 9-314145

The present inventor has studied for the purpose of obtaining a method of reducing the residual rate of unelectrolyzed substances to the limit while proceeding with the intended electrolytic reaction and suppressing the formation of by-products. The above-mentioned multi-stage electrolytic ionic water generator is a method of electrolysis by adding a new raw material to the electrolyte, so it is considered possible to increase the product concentration. Since it has not been done, the impurity concentration due to undecomposition should be high. It can be seen that such a method cannot achieve the original purpose because the use of the product may be limited.

Moreover, in the apparatus which accommodated the several electrolytic cell unit in the above-mentioned one electrolytic cell, it is the same as the state which slowed down the flow rate in order to lengthen residence time in continuous production | generation, and production | generation efficiency worsens. Furthermore, the operating conditions of each electrolytic cell unit are not mentioned, but if they are the same, it is difficult to change the ratio of unelectrolyzed substances.

Accordingly, the present inventor has solved the problem that the present invention provides an electrolytic cell capable of dramatically reducing the remaining ratio of unelectrolyzed material while suppressing the production of by-products without sacrificing the production efficiency. It was a challenge to try.

In continuous electrolysis, since only one type of voltage and current combination can be set in one set of electrolytic cells, electrolysis can be performed only at the electrolysis conditions corresponding to the average of the composition of the electrolyzed substance at the electrolytic cell inlet and the composition of the outlet. I confirmed that I couldn't. Therefore, in order to obtain an electrolysis state further advanced than the outlet composition, it was confirmed that there was no method other than using a plurality of electrolysis units that can set electrolysis conditions independently, and based on each of the following each An embodiment was provided.

First, in continuous electrolysis, as an electrolytic cell capable of reducing the ratio of unelectrolyzed substances, at least the voltage between the counter electrodes is set independently between the electrolytic cells to constitute a flow path in a certain direction of the object to be electrolyzed. A composite electrolytic cell composed of two or more electrolytic cells arranged as described above was defined as the first aspect of the problem solving means.

In the first aspect, among the electrolytic cells constituting the composite electrolytic cell, at least one of the electrolytic cells having a different electrode configuration from the other electrolytic cells is defined as the second aspect of the problem solving means.

Furthermore, in the first or second aspect, a composite electrolytic cell including at least one monopolar electrolytic cell and at least one bipolar electrolytic cell is defined as a third aspect of the problem solving means.

Furthermore, in any one of the first to third aspects, the combined electrolytic cell is a constant voltage electrolytic cell, and the voltage between the counter electrodes is different between the combined electrolytic cells. The fourth aspect of the present problem solving means is provided.

Furthermore, in any one of the first to fourth aspects, a composite electrolytic cell in which the electrolytic treatment in each of the combined electrolytic cells is performed in close contact with each other in a continuous manner. It was set as the aspect.

Furthermore, in any one of the first to fifth aspects, in the electrolytic treatment performed in close time and continuously, the composite electrolytic cell in which the voltage between the counter electrodes is lower in the electrolytic cell that is earlier in time. Is the sixth aspect of the problem solving means.

And finally, in any one of the first to sixth aspects, the difference in the voltage between the counter electrodes between the combined electrolytic cells is 0. A composite electrolytic cell having a voltage of 1 to 3 volts was used as the seventh aspect of the problem-solving means, thereby completing the present invention.

The effects of the present invention are as follows. First, a composite electrolytic cell composed of two or more electrolytic cells in which at least the voltage between the counter electrodes is set independently between the electrolytic cells and arranged to form a flow path in a certain direction of the object to be electrolyzed. The following effects can be obtained. Since it is possible to perform electrolysis at a voltage different from the electrolysis voltage in the first electrolytic cell, it becomes possible to change the electrolysis conditions essentially, and even in continuous electrolysis, the ratio of unelectrolyzed substances can be reduced. Became easier.

In addition, at least one of the electrolytic cells constituting the composite electrolytic cell is a composite electrolytic cell having a different electrode configuration from the other electrolytic cells, so that the set electrolytic conditions, that is, the electrolytic voltage, the electrolytic current, and the retention of the object to be electrolyzed. Time and the like can be set freely, and the setting of electrolysis conditions for further reducing the ratio of unelectrolyzed materials has become easier.

Furthermore, the use of a composite electrolytic cell including at least one monopolar electrolytic cell and at least one bipolar electrolytic cell makes it easier to set the electrolysis conditions and to select a power source.

Furthermore, all the combined electrolytic cells are constant voltage electrolytic cells, and the voltage between the opposing electrodes is different among the combined electrolytic cells. It was possible to fix and set differently from the others, and it became easier to set the electrolysis conditions to further reduce the ratio of undecomposed matter.

Furthermore, since the electrolytic treatment in each of the combined electrolytic cells is made in time, and the composite electrolytic cells are continuously performed, the incompletely electrolyzed substances are retained and the side reaction proceeds. The possibility could be minimized.

Furthermore, in the electrolytic treatment performed in close time and continuously, the electrolytic cell which is earlier in time is a composite electrolytic cell in which the voltage between the counter electrodes is lower as the electrolytic cell is earlier in time. Electrolytes can be electrolyzed efficiently.

And finally, a composite electrolytic cell in which the voltage difference between the counter electrodes between the combined electrolytic cells is 0.1 volts or more and 3 volts or less between the electrolytic cells that are in close contact with each other immediately before or immediately in time. As a result, it became possible to efficiently perform electrolysis of unelectrolyzed materials while suppressing electrolytic side reactions.

Next, the best mode for carrying out the present invention will be described and explained for an accurate understanding of the present invention.
The composite electrolytic cell in the present invention refers to an electrolytic cell composed of a plurality of electrolytic cells functioning independently or semi-independently. Each of the electrolytic cells constituting them may be arranged so as to constitute one flow path of the electrolyte solution, or may be arranged so as to constitute a plurality of flow paths of the electrolyte solution branched in the middle. . A counter electrode is an electrode that directly faces the electrolyte solution, regardless of whether it is a bipolar or monopolar type, and the calculated or theoretical voltage between the facing electrodes is the voltage between the opposing electrodes. . With two or more electrolytic cells in which the voltage between the counter electrodes is set independently, the voltage between the counter electrodes of the individual cell forming the composite electric hierarchy is always set independently of each other. Must have been.

Bipolar and monopolar types can be used properly depending on the purpose and scale of electrolysis. When the product reaction and efficiency depend on a narrow range of electrolysis voltage, a finer voltage setting is desirable, and therefore a monopolar type is preferred. This is because in the bipolar type, the actual voltage distribution may slightly change depending on the concentration distribution of the electrolyte solution between the electrodes and the state of the electrode surface. However, a bipolar type is suitable for a high-capacity electrolytic cell from the viewpoint of construction technology of the electrolytic cell. Therefore, a method of arranging a bipolar type in the former stage electrolysis that will be responsible for electrolysis of more substances in a unit time and arranging a single pole type in the latter stage is considered preferable.

The electrolysis method is often selected from the two methods of constant voltage and constant current, but constant current is convenient when priority is given only to the amount of substance produced, while the complete purpose of raw materials is the main purpose. Is preferably a constant voltage. Moreover, when aiming at complete conversion of a substance, the process by the several voltage of the range which does not raise | generate a side reaction is suitable for control of an electrolysis grade.

As the electrolysis progresses, the concentration of the raw material substance in the electrolyte solution decreases. Accordingly, the electrolytic reaction cannot be maintained unless the voltage corresponding to the increase in electrolytic resistance is increased as the subsequent electrolytic cell is formed. However, the upper limit of the voltage is a voltage at which impurity generation due to side reactions does not occur. In many electrolysis reactions such as chlorine production reaction, the limit voltage of side reaction is about 5V. Therefore, the voltage increase between the electrolyzers is 0.1% so that the voltage across the counter electrode in the subsequent electrolyzer does not exceed it. From 3 to 3 volts, and in some cases, from 0.1 to 1 bolt are suitable.

Next, the present invention will be described in more detail with reference to examples. FIG. 1 is a schematic vertical sectional view of a composite electrolytic cell that electrolytically oxidizes chlorine ions to produce a chlorine solution. This composite electrolytic cell is composed of two electrolytic cells, a two-cell bipolar electrolytic cell (1) and a single-cell single-electrode electrolytic cell (2). The electrode plates are all the same size and 100 × 150 mm, and the anode side is coated with iridium oxide and the cathode side is coated with platinum (Tanaka Kikinzoku Co., Ltd.). The electrode plate is fixed to a groove provided in the resin frame (5, 6, 7), and the frame is fixed to the outer casing (15). Hydrochloric acid, which is the substance to be electrolyzed, is stored in the raw material tank (11), and is first supplied to the main electrolytic cell (1) and electrolyzed by the pump (10) and then supplied to the secondary electrolytic cell (2). The broken line arrow (9) indicates the flow direction of the electrolyte solution. There is a flow of water for cooling and chlorine dissolution (8, solid line arrow) around the electrolytic cell, which is mixed with the electrolyte to be discharged from the electrolytic cell at the outlet of the composite electrolytic cell, and the chlorine solution (12) And discharged. As a power source (13) for the main electrolytic cell, LPS62 manufactured by ASTEC was used, and as a power source for the secondary electrolytic cell (14), PBA75F-3R3 manufactured by Cosel was used. The voltage between the counter electrodes of each electrolytic cell was 2.2 V and 2.8 V, respectively. Using this combined electrolytic cell, a 6% hydrochloric acid solution is supplied as a raw material at a flow rate of 220 ml / h, the amount of dilution water is made to flow at 300 L / h, the main electrolytic cell is set to 8A, and the auxiliary electrolytic cell is set to 8A for electrolysis. did. The obtained chlorine solution was 41 ppm, and the conversion rate from chlorine ions to chlorine by electrolysis was about 98%.

Cross-sectional schematic diagram of a composite electrolytic cell

Explanation of symbols

3 Main electrolytic cell electrode plate 4 Sub electrolytic cell electrode plate

Claims (7)

A composite electrolytic cell composed of two or more electrolytic cells in which at least the voltage between the counter electrodes is set independently between the electrolytic cells and arranged to form a flow path in a certain direction of the object to be electrolyzed 2. The composite electrolytic cell according to claim 1, wherein at least one of the electrolytic cells is different in electrode configuration from the other electrolytic cells. The composite electrolytic cell according to claim 1, comprising at least one monopolar electrolytic cell and at least one bipolar electrolytic cell. 4. The composite electrolysis according to claim 1, wherein all of the combined electrolytic cells are constant voltage electrolytic cells, and the voltage between the counter electrodes is different among the combined electrolytic cells. 5. Tank 5. The composite electrolytic cell according to claim 1, wherein the electrolytic treatment in each of the composite electrolytic cells is performed in close contact with each other and continuously. 6. The electrolytic treatment performed closely in time and continuously, the voltage between the counter electrodes is lower in an electrolytic cell in which the treatment is earlier in time. Composite electrolytic cell The voltage difference between the counter electrodes between the combined electrolytic cells is 0.1 to 3 volts between the electrolytic cells that are in close contact with each other immediately before or after time, Item 7. The composite electrolytic cell according to any one of Items 1 to 6