DE1956441A1 - Chlorine cell - Google Patents

Description

D 1658

Dow Chemical Company, Midland / Michigan / USA

"Chlorine cell ^»

The invention relates to chlorine cells and, more particularly, to diaphragm-type electrolysis cells which are used in used in the production of chlorine. For electrolysis cells of the diaphragm type with a Electrode higher than 91 »4 cm in which a gas generated at either the anode or the cathode or both has been practiced It has long been believed that when larger cells are built there are serious limitations on cell height occur due to the clogging of the electrode area in the upper portion a cell by the cell evacuated gas, resulting in poor power distribution and occurring ineffective operation of the cell.

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Motonobu Minagawa came to such conclusions and Tadas üeda in their publication "Studies on Electrolysis in Diaphragm Cells" (Part III), Denki Kagalcu (Electro-Chem., Japan) 25, 210-215 (1967).

According to the invention there is an electrolysis cell of the diaphragm type with an effective anode height 1.07 m or more with a redistribution facility for the Anolyte flow is provided, thereby allowing the circulation of the anolyte between between the bottom and top of the anode (s) in a given compartment of the electrolyzer 18.9 and 37.9 liters / min. Kilo lamps * re applied by the compartment. The redistribution facility for the anolyte can be outside or inside the electrolyzer structure be arranged.

The invention is explained in more detail below with reference to the accompanying drawings.

In the drawings show:

lig.l a partially broken away and.in section shown side view of a device according to the invention,

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Pig. 2 a center view according to line 2-2 in Pig. 1, Pig. 3 a sectional view along line 3-3 in Pig. 1, and

Pig.4 a partial section, similar to Pig.2, with the external device for redistributing the anolyte is shown.

With reference to particularly Pig. 1, 2 and 3, a diaphragm-type chlorine cell 10 is shown, which an electrolyzer housing 12 with a bottom 14, cover 16, sides 19, 20 and ends 18a, 18b, which each consist of conventional cement structures as is known in the art.

Inside the housing there is an anode back wall, usually made of graphite, with which anodes 30, for example made of rigid graphite, are mechanically and electrically coupled, wherein the anodes 30 are arranged substantially perpendicular to the wall plate 28, which against the side wall 19 rests. The οcere wall 16 has a passage 22 through which chlorine is withdrawn from the line. The electrolyzer

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Unit is supplied with a saline solution through a passage 24 in the lid 16, and catholyte is discharged through passage 26 at the bottom of the cell. A separator not shown is used to adjust the level 60 of catholyte in the cell. The mirror 34 of the anolyte is during operation of the cell above the level 60 of the Catholyte held.

A bundle of cathode pockets 32 extending upward from a rear screen 34, form the cathode-diaphragm structure of the cell. As can be seen in Figure 2, extend from the cement sidewall 20 lugs 36, which means forming the cathode-diaphragm-ochirmstruktur less subject to bending.

Lines 40, 42 are used to direct current of the anode BEZW. to feed the cathode.

The upper end of the screen 34 is before the attack protected by chlorine by a cereal spine 62 within which the screen 34 adheres. The back extends below the level 34 of the anolyte in the cell.

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As shown in Pig. 3, there is a larger than normal space between the outer ends of the Pockets 32 and the rear panel 28 are provided. The area generally designated 48, which of the ends of the pockets 32, the end plate 28 and the portion of the adjacent Anodes 30 is limited, forms a device for redistributing the anolyte in In accordance with the invention.

There can also be an increased space between the outer ends 64 of each anode and the rear screen 34 may be provided to provide an enlarged redistribution facility of the devices described above can be used in a single electrolyzer cell.

It is desirable that the redistribution of the anolyte be relatively free of electrolyte shear activity, and in order to achieve this, as shown at 46 and / or 66, a Layer of insulating material such as phenol formaldehyde can be applied.

The invention is based on the knowledge that in the formation of electrolysis cells of the diaphragm type, in which the effective electrode height

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taller than 1.07 m, it is essential for effective operation of the cells are necessary both in terms of power consumption and distribution is that between the bottom and the upper ends of the anode (s) there are circulating amounts of anolyte / saline used so that the ratio of the anolyte-saline flow in a given compartment of the electrolyzer to the amount of that flowing through the compartment Flows in the range of 18.9 to 37.9 (preferably 26.5 liters / min kiloampore) through the compartment is. The preferred method of achieving this circulation is by providing a facility to redistribute the electrolyte close to and at right angles to the electrode surfaces achieved whose cross-sectional area, measured in a horizontal plane, through the

ρ relationship is determined: The area in cm is equal to or greater than the kiloampe're load in this compartment of the electrolyzer. This preferential circulation can also be obtained by that the anolyte saline solution is pumped from the outside to the cell. If the redistribution facility is arranged next to the electrodes, it is preferably prevented from Conduct electricity.

A hydrogen vent 61, which is shown in Pig.2

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is provided at the upper end of the compartment of the catholyte.

While the throughput of the salt solution in an electrolysis unit is only a few Liters / «in can be the circulation in the electrolyzer more than a few 100 liters /

min because of the gas lift pump effect between the λ

Anodes and the cathodes. Provided that the required circulation paths are in compliance with the discovery of a massive flow of liquid between the anodes and cathodes allow, which allows the removal of chlorine from the area while sufficient Maintain supply of liquid even at the upper parts of the anodes and cathodes effective operation of the cells is ensured, with the electrodes up to can be 2.4, 3, 3.6m and more high.

A modified facility to achieve the (

Saline circulation in a series type chlorine cell is shown in Fig. 4.

A tubular circulation line 48 with a pump 58, which is provided therein, extends through bores 50, 56 in the upper and lower Sections of wall 19a and through graphite plate 28a. The hole 50 is above and the Bore 58 is provided below the anode 30a.

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Chlorine exits through outlet 22a and is collected in cap 44. The bottom 14a is equal to the bottom 14, which is shown in Fig.l and 2.

Outer redistribution lines 48, which are arranged along the electrolyzer body, complement the limited internal return path for the circulation of the anolyte opposite the well-known chlorine cells.

In this way, the device for circulating the anolyte according to the invention designed inside, outside or as a combination in relation to the housing of the electrolyzer be.

Patent claims:

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BATH ORIGINAL

Claims (11)

Patent claims : ·;1. Electrolytic manufacturing process of chlorine, characterized in that a salt solution is passed through an electrolysis unit which has a bundle of interspersed anodes and cathodes that the anodes and cathodes a direct current is supplied and then the chlorine from the upper part of this electrolysis unit is withdrawn with the saline solution up between each adjacent anode and The cathode is circulated in an amount of 18.9 to 37.9 liters / min / 1000 amperes of the current, which flows between the anode and the cathode. 2. The method according to claim 1, characterized in that said amount is 26.5 l / min amounts to. 3. Diaphragm-type chlorine cell characterized by a surrounding case, a bundle Layered anode and cathode elements, which have a height of at least 1.07 m and are distributed within the housing, - 10 - 009832/1806 - ίο - through inlet and outlet means for circulating the saline solution through the I-housing means for supplying direct current to the anode and cathode elements, through a Means for removing the chlorine above the anode elements and by means of a device for circulating the saline solution upward between each adjacent anode and cathode element with an amount of 18.9 to 37.9 liters / min / 1000 Ampe * re of the current, which between the adjacent anode and cathode element is applied. 4. Chlorine cell according to claim 3, characterized in that that the device for circulating the saline solution also removes sodium hydroxide serves. 5. Chlorine cell according to claim 3, characterized in that the height of the anode and cathode is between 1.07 m and 4.57 m. 6. chlorine cell according to claim 3, characterized in that the device for circulating the Saline solution inside the housing and next to each - 11 G09832 / 1806 - li - a return channel to the anode and cathode element for the saline solution, whose effective cross-sectional area (in square inches) is equal to or greater than the number of kiloamps with which each adjacent anode and cathode element is applied. 7. Chlorine cell according to claim 6, characterized by J shows that the return channel for the saline solution is essentially electrolytically inactive. 8. chlorine cell according to claim b, characterized in that that the return channel for the saline solution is arranged between a pair of anode elements and that the end of a cathode element is provided between the anaenous elements, 9. Chlorine cell according to claim b, characterized in that the return channel for the salt solution is provided between the end of an anode element and the adjacent cathode assembly. - 12 - 009832/1806 Ί956441 10. Chlorine cell according to claim 3, characterized in that at least part of the device for upward circulation of the saline solution between each adjacent anode and Cathode element comprises a flow tube outside the housing, one end of which in the vicinity of the upper portion of the adjacent anode and cathode elements and the other End near the bottom of each adjacent anode and cathode element is. 11. Chlorine cell according to claim 10, characterized in that that the flow line has a pump device. 009832/1806 Blank page