Electrolytic cells for chlor-alkali electrolysis, electrolytic equipment, and use of electrolytic cells for chlor-alkali electrolysis

Abstract

The present invention relates to an electrolytic cell (1) for chloralkali electrolysis comprising an anode chamber (2) for accommodating an anode (4) and for accommodating an electrolyte, the anode chamber (2) comprising a circulation structure (5) for improving the circulation of the electrolyte and at least one baffle plate (6) for improving the horizontal uniformity of the electrolyte, as well as to an electrolysis device comprising such an electrolytic cell (1) and to the use of the electrolytic cell (1) for chloralkali electrolysis.

Description

[Technical field]

[0001] The present invention relates to an electrolytic cell and an electrolytic device for chloralkali electrolysis and to their use for chloralkali electrolysis. [Background technology]

[0002] Chloralkali electrolysis is a process that uses electrical energy and an electrolytic cell to produce chlorine gas, hydrogen, and hydroxide gas from an aqueous solution of an alkali chloride. The alkali chloride is generally sodium chloride or potassium chloride. The reaction equation for the electrolysis of an aqueous solution of sodium chloride is as follows:

[0003] 2NaCl+2H 2 O→Cl 2 +H 2 +2NaOH

[0004] The general configuration of electrolysis cells and electrolysis devices for chloralkali electrolysis is known from the prior art, for example US 6,282,774, WO 2009 / 007366, WO 2004 / 040040 and WO 2010 / 055152 relate to electrolysis cells and electrolysis devices for chloralkali electrolysis.

[0005] During the electrolysis process, the electrolyte is consumed at the electrode surface, and gas is produced at the electrode surface. In other words, the density, temperature and composition of the electrolyte at the electrode surface change, and gas bubbles are generated at the electrode surface. The presence of gas bubbles or the uneven distribution of electrolyte, density and temperature in the electrolyte are not favorable for a stable and efficient electrolysis process.

[0006] DE 44 15 146 A1 aims to improve the efficiency of chloralkali electrolysis by preventing gas accumulation using specially shaped electrodes. Such electrolysis cells have a low specific current consumption and an even distribution of the current over the electrode and membrane surfaces, which has a beneficial effect on the service life of the membrane and electrodes.

[0007] US Patent No. 6,503,377 also aims to more efficiently remove gas bubbles from an electrode, which is specially shaped to accumulate and remove the generated gas bubbles, which creates a circulation around the surface of the electrode.

[0008] US 2006 / 0042935 describes the use of vertical baffle plates or cylindrical ducts to provide a more uniform distribution of electrolyte within the electrolyte solution.

[0009] US Patent Application Publication No. 2017 / 0306513 discloses an ion exchange membrane electrolysis cell having a circulation path, which is formed by one or more circulation plates provided on the base plate of the anode chamber and / or the cathode chamber. When the circulation plate has a specially shaped plate structure, not only the circulation in the vertical direction of the electrolysis cell but also the circulation in the depth direction of the electrolysis cell can be promoted.

[0010] US Patent No. 6,200,435 describes an electrolytic cell comprising a vertical cell unit having a partition wall with a concave and convex surface that overlaps and merges with the partition wall, and an electrode plate is connected to the convex part of the partition wall.

[0011] U.S. Pat. No. 6,773,561 discloses a unit cell including an anode compartment with a baffle plate disposed on top of the anode compartment, the baffle plate being arranged such that an upward flow path is formed between the baffle plate and the anode, and a downward flow path is formed between the baffle plate and the back inner wall of the anode compartment. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] U.S. Patent No. 6,282,774 [Patent Document 2] International Publication No. 2009 / 007366 [Patent Document 3] International Publication No. 2004 / 040040 [Patent Document 4] International Publication No. 2010 / 055152 [Patent Document 5] DE 4415146 A1 [Patent Document 6] U.S. Patent No. 6,503,377 [Patent Document 7] US Patent Application Publication No. 2006 / 0042935 [Patent Document 8] US Patent Application Publication No. 2017 / 0306513 [Patent Document 9] U.S. Patent No. 6,200,435 [Patent Document 10] U.S. Patent No. 6,773,561 Summary of the Invention [Problem to be solved by the invention]

[0013] As described above, several attempts have been made to improve the stability and efficiency of the electrolysis process. However, there is a need to further improve the stability and efficiency of the electrolysis process. The present invention has been made in view of this problem, and has an object to improve the uniformity of the electrolyte in order to improve the stability and efficiency of the electrolysis process. [Means for solving the problem]

[0014] In a first aspect of the invention, the inventors propose an electrolytic cell for chloralkali electrolysis comprising an anode compartment for accommodating an anode and for accommodating an electrolyte, characterized in that the anode compartment comprises a circulation structure for improving electrolyte circulation and at least one baffle plate for improving electrolyte uniformity, preferably for improving electrolyte horizontal uniformity.

[0015] The circulation structure and at least one baffle plate are different structures. The inventors have found that by using these structures, the uniformity of the electrolyte with respect to the concentration of chemical molecules in the electrolyte is improved in an unexpected way. The demonstrated effect can also be envisaged for the uniformity of density and temperature in the electrolyte.

[0016] The electrolytic solution may refer to the anolyte. The electrolytic solution preferably contains an aqueous sodium chloride solution or an aqueous potassium chloride solution. The electrolytic solution preferably contains 100 to 400 g / L, more preferably 150 to 300 g / L, and even more preferably 180 to 280 g / L of sodium chloride or potassium chloride and water. The anode chamber preferably contains the electrolytic solution.

[0017] The term "homogeneity of the electrolyte" means that the density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte is uniform or similar at various points in the anode chamber.

[0018] The term "improving the uniformity of the electrolyte" means making the density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte more uniform or similar at various locations in the anode chamber. In other words, the term "improving the uniformity of the electrolyte" means approximating / aligning / synchronizing / equalizing the density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte at various locations in the anode chamber.

[0019] The term "improving the horizontal uniformity of the electrolyte" means making the density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte more uniform or similar at various points in the anode chamber, where the electrolyte is considered as a stack of horizontal layers and the density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte more uniform or similar within at least one horizontal layer. Preferably, this at least one horizontal layer is at the lower end (towards the centre of gravity) of the anode chamber and / or near the inlet of the anode chamber.

[0020] The term "similar density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte" means a maximum difference of 5, 10, 15, 20, 25, 30, or 35% between various points within the anode chamber and / or horizontal layer.

[0021] The anode chamber comprises an anode. Preferably, the anode is disposed essentially vertically within the anode chamber. Preferably, the anode chamber has its longest dimension / expansion in the vertical direction.

[0022] The anode may be a single structural element or may comprise several structural elements. The anode may have the form of a mesh.

[0023] The electrolytic cell for chloralkali electrolysis may include further elements known to those skilled in the art and useful for conducting chloralkali electrolysis.

[0024] Such an element is for example a cathode compartment for housing the cathode and for housing the catholyte. In one embodiment, the electrolytic cell comprises a cathode compartment for housing the cathode and for housing the catholyte. In one embodiment, the cathode compartment comprises the cathode and the catholyte. The cathode may be a single structural element or may comprise several structural elements. The cathode may have the form of a mesh.

[0025] Preferably, the anode and cathode compartments are separated by an ion exchange membrane. Preferably, said membrane is semi-permeable. In other words, said membrane preferably allows the exchange of sodium and / or potassium ions between the anode and cathode compartments. In other words, the electrolysis cell preferably comprises an ion exchange membrane.

[0026] The circulation structure described above improves the circulation of the electrolyte in the anode chamber, but this also benefits the cathode reaction by increasing the flow rate of alkali through the ion exchange membrane.

[0027] The electrolysis cell may further comprise elements known to those skilled in the art, such as a gas and liquid separator, a current distributor, an inlet, a product outlet, etc. For example, the anode chamber may have at least one inlet for a stream comprising 150-450 g / L, preferably 200-400 g / L, more preferably 250-350 g / L, most preferably about 300 g / L sodium chloride and / or potassium chloride and water. Furthermore, the anode chamber may have one product outlet for chlorine gas, preferably at the upper end of the anode chamber (away from the center of gravity). Furthermore, the anode chamber may have one outlet for a stream comprising an aqueous sodium chloride solution and / or an aqueous potassium chloride solution.

[0028] The anode chamber has an upper end (away from the center of gravity) and a lower end (towards the center of gravity).

[0029] The electrolytic cell may be a zero gap cell.

[0030] The verbs "comprise" and "include" and their conjugations include the verb "consist of" and its conjugations.

[0031] The term "at least one" is inclusive of the term "one." The term "one" is inclusive of the term "at least one."

[0032] The claims include preferred embodiments.

[0033] Preferably, the circulation structure is a structure for circulating the electrolyte around the circulation structure, in other words, the circulation of the electrolyte around the circulation structure is preferably in the form of a loop, which, if the circulation structure is appropriately designed, increases the uniformity throughout the anode chamber.

[0034] Preferably, the circulation structure is a structure for essentially vertical circulation of the electrolyte.

[0035] The anode in the anode chamber generates chlorine gas bubbles from the electrolyte. These gas bubbles are less dense than the surrounding electrolyte and flow to the top of the anode chamber (away from the center of gravity). The rising gas bubbles attract more electrolyte from the lower part of the anode chamber. This "gas lift effect" is used in the present invention. By locating a circulation structure adjacent to the anode area, the gas lift effect creates a high degree of vertical circulation. The high degree of circulation mixes the electrolyte and improves the uniformity of the electrolyte. Thus, the circulation structure is preferably a structure for improving the vertical uniformity of the electrolyte.

[0036] The term "improving the vertical uniformity of the electrolyte" means making the density and / or temperature and / or concentration of sodium chloride and / or potassium chloride in the electrolyte more uniform or similar at various vertical points within the anode chamber.

[0037] Preferably, the circulation structure forms at least one downcomer in the anode chamber. The term "downcomer" is intended to denote an at least partially defined area of ​​the anode chamber that extends vertically and is open at its upper end and at its lower end. More preferably, the circulation structure forms a plurality of downcomers in the anode chamber. The shape of the downcomers allows particularly good vertical circulation to improve vertical uniformity.

[0038] Preferably, the circulation structure and / or the at least one downcomer are arranged essentially parallel to the anode.

[0039] The circulation structure divides the anode chamber into an upflow section and a downflow section, each containing electrolyte. The upflow section is characterized by gas bubbles flowing from the anode (away from the center of gravity) to the top of the anode chamber.

[0040] Preferably, the upflow section is located between the anode and the circulation structure.

[0041] In one embodiment, the upflow section is located between the anode and a surface of the circulating structure facing the anode, and the downflow section is located on a surface of the circulating structure opposite the anode.

[0042] Preferably, the ratio of the cross section of the upflow section to the cross section of the downflow section is 1 or less, preferably 0.8 to 0.3, more preferably 0.6 to 0.4, and most preferably about 0.43. This ratio allows a certain homogeneous electrolyte solution to be obtained.

[0043] Preferably, the cross section of the upflow section plus the cross section of the downflow section is between 5 and 100 cm 2 , more preferably 7 to 50 cm 2 It is.

[0044] In one embodiment, at least one downcomer has / forms a V-shape (when viewed from above). In another embodiment, at least one downcomer has / forms the shape of a trough (when viewed from above). In another embodiment, at least one downcomer has / forms the shape of one half of a regular hexagon (when viewed from above). Each of the above shapes allows for good circulation. Preferably, the apex of the V faces towards the anode. Preferably, the trough opens towards the anode.

[0045] The anode and circulation structure extend along the height of the anode chamber.

[0046] Preferably, the circulation structure and / or at least one downcomer has a height of 50-100%, preferably 60-98%, more preferably 70-96% of the height of the anode. This height allows a specific uniform electrolyte to be obtained. In one embodiment, 92-99% is preferred, and 93-98% is even more preferred. In another embodiment, 60-85% is preferred, and 65-80% is even more preferred.

[0047] Preferably, the circulation structure and / or at least one downcomer extends along 50-100%, preferably 60-98%, more preferably 70-96% of the height of the anode. This height allows a certain homogeneity of the electrolyte. In one embodiment, 92-99% is preferred, and 93-98% is even more preferred. In another embodiment, 60-85% is preferred, and 65-80% is even more preferred.

[0048] Preferably, the anode has a length of from 100 to 160 cm, more preferably from 120 to 140 cm.

[0049] Preferably, the circulation structure and / or the at least one downcomer has a length of between 50 and 160 cm, more preferably between 60 and 140 cm.

[0050] In particular in zero gap cells, where the ion exchange membrane is generally pressed against the anode by pressure from the cathode compartment, it is preferred to mechanically stabilize the anode. Preferably, the circulation structure and / or the at least one downcomer are structures for (mechanically) supporting the anode. Preferably, the circulation structure and / or the at least one downcomer support (mechanically) the anode, in particular against pressure from the cathode compartment.

[0051] In one embodiment, one baffle plate is preferred.

[0052] At least one baffle plate is arranged horizontally or essentially horizontally. The term "essentially horizontal" means "horizontal" or "having an inclination of less than 45°, particularly less than 30, 20, 10, or 5°, relative to a horizontal line." Horizontal baffle plates are particularly useful for improving uniformity in combination with vertical circulation provided by the circulation structure.

[0053] Preferably, each baffle plate has a length of from 10 to 235 cm, preferably from 26 to 235 cm, and / or a width of from 5 to 20 cm, preferably from 7 to 15 cm.

[0054] Preferably, the baffle plate is horizontal and / or has a horizontal surface.

[0055] The baffle plate may have perforations to create perturbations, which improves electrolyte uniformity in the anode compartment.

[0056] At least one baffle plate is positioned such that the flow from at least one inlet of the anode chamber impinges on the baffle plate. In other words, the flow from at least one inlet of the anode chamber is directed to the baffle plate. Preferably, the at least one inlet of the anode chamber is at the lower end (in the direction of the center of gravity) of the anode chamber. The flow comprises 150-450 g / L, preferably 200-400 g / L, more preferably 250-350 g / L, most preferably about 300 g / L of sodium chloride and / or potassium chloride and water. The baffle plate creates a perturbation, which improves mixing with the electrolyte in the anode chamber and improves the uniformity of the electrolyte in the anode chamber.

[0057] The at least one baffle plate is positioned such that the electrolyte flow from the circulation structure and / or the at least one downcomer (i.e., from the downflow region) impinges on the baffle plate. In other words, the electrolyte flow from the circulation structure and / or the at least one downcomer (i.e., from the downflow region) is directed towards the baffle plate. This improves the electrolyte uniformity in the anode chamber.

[0058] The at least one baffle plate is arranged such that the flow from the at least one inlet of the anode chamber impinges on the baffle plate and the flow of electrolyte from the circulation structure and / or the at least one downcomer (i.e. from the downflow section) impinges on the baffle plate. This improves, among other things, the mixing of the electrolyte in the anode chamber and improves the homogeneity of the electrolyte in the anode chamber. In one embodiment, the flow from the at least one inlet of the anode chamber impinges on the bottom surface of the at least one baffle plate and the flow of electrolyte from the lower end of the circulation structure and / or the at least one downcomer (i.e. from the downflow section) impinges on the upper surface of the baffle plate. Preferably, the at least one inlet of the anode chamber is at the lower end (in the direction of the center of gravity) of the anode chamber.

[0059] In a second aspect, the invention relates to an electrolysis device for chloralkali electrolysis comprising at least one electrolysis cell according to the invention.

[0060] Such an electrolytic device may represent an electrolytic cell.

[0061] The electrolysis apparatus comprises a plurality of electrolysis cells according to the invention.

[0062] The electrolyser may be a filter press electrolyser and / or a bipolar ion exchange membrane process electrolyser.

[0063] The electrolysis apparatus for chloralkali electrolysis may comprise further elements known to those skilled in the art and useful for carrying out chloralkali electrolysis.

[0064] In a third aspect, the present invention relates to the use of an electrolysis cell according to the invention or an electrolysis device according to the invention for chloralkali electrolysis.

[0065] The embodiments described herein for each aspect of the invention may be combined in any manner. Furthermore, the embodiments described for the three aspects of the invention may be combined in any manner.

[0066] Selected embodiments of the invention will now be described with the aid of the following figures. [Brief description of the drawings]

[0067] [Figure 1] 1 shows an electrolytic cell according to the invention for chloralkali electrolysis. [Diagram 2] One baffle plate is shown, which is positioned so that the flow from the two inlets of the anode chamber impinges on the baffle plate. [Figure 3A] 1 shows a downcomer supporting the anode. [Figure 3B] 1 shows a downcomer supporting the anode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] An electrolytic cell 1 according to the invention for chloralkali electrolysis is shown in FIG.

[0069] The electrolysis cell 1 comprises an anode chamber 2 and a cathode chamber 3. The anode chamber 2 comprises an anode 4, an electrolyte (not shown), a circulation structure 5, and one baffle plate 6. The electrolyte contains water and about 180 to 280 g / L of sodium chloride. The anode 4 and the circulation structure 5 extend along the height section of the anode chamber 2.

[0070] The circulation structure 5 divides the anode chamber 2 into an upflow section 7 and a downflow section 8. The ratio of the cross section of the upflow section 7 to the cross section of the downflow section 8 is less than 1. The circulation structure 5 provides a gas lift effect, resulting in a high degree of electrolyte circulation, essentially vertical, around the periphery of the circulation structure 5.

[0071] The anode 4 generates chlorine gas bubbles from the electrolyte. The gas bubbles are less dense than the surrounding electrolyte and flow to the top end of the anode chamber 2, defining the upflow zone 7. The rising gas bubbles attract electrolyte from the lower part of the anode chamber 2. At the same time, electrolyte is entrained and / or expelled by the gas bubbles from the top end of the anode chamber 2, creating the downflow zone 8. The electrolyte flow from the downflow zone 8 impacts the upper surface of the baffle plate 6. A high degree of vertical circulation mixes the electrolyte, improving electrolyte uniformity.

[0072] The electrolysis device according to the invention comprises at least one electrolysis cell 1, preferably several electrolysis cells 1, according to the invention.

[0073] 1, the baffle plate 6 and the inlet 9 are located at the lower end (in the direction of the centre of gravity) of the anode chamber 2. The horizontal baffle plate 6 is shown in more detail in FIG.

[0074] The baffle plate 6 is positioned so that the flow from the two inlets 9 of the anode chamber 2 impinges on the baffle plate 6. The flow contains water and about 300 g / L of sodium chloride. The baffle plate 6 creates a perturbation that forces the flow to mix with the electrolyte, which contains water and about 180-280 g / L of sodium chloride. This improves the uniformity of the electrolyte in the anode chamber 2, especially in the horizontal direction.

[0075] 1, the electrolyte flow from the downflow section 8 also impinges on the baffle plate 6. This results in a specific uniform electrolyte in the anode chamber 2.

[0076] 3A and 3B show a preferred embodiment of the downcomer in top view. The circulation structure 5 forms the downcomer. It mechanically supports the anode 4 against the ion exchange membrane, which may be pressed against the anode 4 by the pressure from the cathode compartment. In FIG. 3A, the downcomer has the shape of a trough. The trough opens towards the anode 4. In FIG. 3B, the downcomer has the shape of half a regular hexagon. In FIGS. 3A and 3B, the downcomer forms a V-shape. The apex of the V points towards the anode 4.

[0077] The effects achieved by selected embodiments of the present invention will now be described using experiments.

[0078] To test the effect of the ratio of the cross section of the upflow section 7 to the cross section of the downflow section 8, the following Experiments 1 and 2 were carried out.

[0079] In accordance with the present invention and shown in FIG. 1, an electrolysis cell 1 was constructed.

[0080] The circulation structure 5 divided the anode chamber 2 into an upflow section 7 and a downflow section 8. In experiment 1, the ratio of the cross section of the upflow section 7 to the cross section of the downflow section 8 was 1.

[0081] Chloralkali electrolysis was started in the electrolysis cell. An aqueous sodium chloride solution containing 300 g / L of sodium chloride was fed into the cell. The concentration of sodium chloride in the electrolyte was measured at 18 different points at six different heights of the electrolysis cell. The results are shown in Table 1.

[0082] [Table 1]

[0083] Table 1: Concentration of sodium chloride in the electrolyte at 18 different points of the electrolytic cell (values ​​in g / L).

[0084] The highest detected concentration difference among the 18 sites was 30 g / L (232 g / L-202 g / L).

[0085] Experiment 2 was carried out in a similar manner. In experiment 2, the ratio of the cross section of the upflow section 7 to the cross section of the downflow section 8 was 0.43. The results are shown in Table 2.

[0086] [Table 2]

[0087] Table 2: Concentration of sodium chloride in the electrolyte at 18 different points of the electrolytic cell (values ​​in g / L).

[0088] The highest detected concentration difference among the 18 sites was 22 g / L (222 g / L-200 g / L).

[0089] The maximum difference among the 18 sites was lower in experiment 2. Furthermore, the concentration difference in experiment 2 was lower along the height of the cell.

[0090] Therefore, to have a homogeneous electrolyte, it is advantageous for the ratio of the cross section of the upflow section 7 to the cross section of the downflow section 8 to be less than 1.

[0091] In order to test the effect of the height of the circulation structure 5 relative to the height of the anode 4, the following Experiments 3 to 5 were carried out.

[0092] In accordance with the present invention and shown in FIG. 1, an electrolysis cell 1 was constructed.

[0093] In experiment 3, the height of the circulation structure 5 was 71% of the height of the anode 4 .

[0094] Chloralkali electrolysis was started in the electrolysis cell. An aqueous sodium chloride solution containing 300 g / L of sodium chloride was supplied to the cell. The concentration of sodium chloride in the electrolyte was measured at six different points at six different heights of the electrolysis cell in two different runs (i.e., n=2). The results are shown in Table 3.

[0095] [Table 3]

[0096] Table 3: Concentration of sodium chloride in the electrolyte (values ​​in g / L) at six different points at six different heights of the electrolytic cell for two different runs.

[0097] The highest mean concentration difference was 17 g / L.

[0098] Experiment 4 was carried out in a similar manner. In experiment 4, the height of the circulation structure 5 was 91% of the height of the anode 4. The results are shown in Table 4.

[0099] [Table 4]

[0100] Table 4: Concentration of sodium chloride in the electrolyte (values ​​in g / L) at six different points at six different heights of the electrolytic cell for two different runs.

[0101] The highest mean concentration difference was 21 g / L.

[0102] Run 5 was carried out in a similar manner. In run 5, the height of the downcomer was 96% of the height of the anode 4.

[0103] Chloralkali electrolysis was started in the electrolysis cell. An aqueous sodium chloride solution containing 300 g / L of sodium chloride was supplied to the cell. The concentration of sodium chloride in the electrolyte was measured at five different points at five different heights of the electrolysis cell in three different runs (i.e., n=3). The results are shown in Table 5.

[0104] [Table 5]

[0105] Table 5: Concentration of sodium chloride in the electrolyte (values ​​in g / L) at five different points at five different heights of the electrolytic cell for three different runs.

[0106] The highest mean concentration difference was 14 g / L.

[0107] To test the effect of the baffle plate 6, the following Experiments 6 and 7 were carried out.

[0108] An electrolysis cell 1 was constructed in accordance with the present invention and shown in Figures 1 and 2. A horizontal baffle plate 6 was placed horizontally. The baffle plate was positioned so that the flows from the two inlets 9 of the anode chamber 2 impinged on the baffle plate 6.

[0109] Chloralkali electrolysis was started in the electrolytic cell. An aqueous sodium chloride solution containing 300 g / L of sodium chloride was supplied to the cell. The sodium chloride concentration in the electrolyte was measured at three different points at the same height at the bottom of the electrolytic cell. The results are shown in Table 6.

[0110] [Table 6]

[0111] Table 6: Concentration of sodium chloride in the electrolyte (values ​​in g / L) at three different points of the same height at the bottom end of the electrolytic cell.

[0112] The highest detected concentration difference among the three sites was 4 g / L (227 g / L-223 g / L).

[0113] Run 7 was carried out in a similar manner. In this control run, not according to the invention, baffle plate 6 was omitted. The results are shown in Table 7.

[0114] [Table 7]

[0115] Table 7: Concentration of sodium chloride in the electrolyte (values ​​in g / L) at three different points of the same height at the bottom end of the electrolytic cell.

[0116] The highest detected concentration difference among the three sites was 16 g / L (228 g / L-212 g / L).

[0117] From this experiment, it is clear that the baffle plate 6 improves the horizontal uniformity of the electrolyte. [Explanation of symbols]

[0118] 1 Electrolysis cell 2 Anode chamber 3. Cathode chamber 4 Anode 5 Circulation structure 6 Baffle Plate 7 Upward flow area 8 Downdraft area 9 Entrance

Claims

1. An electrolytic cell (1) for chloralkali electrolysis, said electrolytic cell (1) comprising an anode chamber (2) containing an anode (4) and for containing an electrolyte, The anode chamber (2) comprises a circulation structure (5) for improving the circulation of the electrolyte, and at least one baffle plate (6) for improving the horizontal uniformity of the concentration, density or temperature of chemical molecules in the electrolyte, The circulation structure (5) and the at least one baffle plate (6) are different structures; the anode (4) and the circulation structure (5) extend along a height section of the anode chamber, The circulation structure (5) divides the anode chamber (2) into an upflow section (7) and a downflow section (8); The at least one baffle plate (6) is arranged horizontally or at an angle of less than 45° to a horizontal line; the at least one baffle plate (6) is arranged such that a flow from at least one inlet (9) of the anode chamber (2) impinges on a bottom surface of the baffle plate (6); The at least one baffle plate (6) is arranged so that a flow of the electrolyte from the lower end of the circulation structure (5) impinges on an upper surface of the baffle plate (6). Electrolysis cell (1).

2. Electrolysis cell (1) according to claim 1, characterized in that the circulation structure (5) is arranged parallel to the anode (4).

3. 3. Electrolysis cell (1) according to claim 1 or 2, characterized in that the ratio of the cross section of the upflow section (7) to the cross section of the downflow section (8) is 1 or less than 1.

4. 3. Electrolysis cell (1) according to claim 1 or 2, characterized in that the ratio of the cross section of the upflow section (7) to the cross section of the downflow section (8) is between 0.8 and 0.

3.

5. 3. Electrolysis cell (1) according to claim 1 or 2, characterized in that the ratio of the cross section of the upflow section (7) to the cross section of the downflow section (8) is 0.

43.

6. Electrolysis cell (1) according to any one of claims 1 to 5, characterized in that the circulation structure (5) has a height between 50 and 100% of the height of the anode (4).

7. Electrolysis cell (1) according to any one of claims 1 to 5, characterized in that the circulation structure (5) has a height between 60 and 98% of the height of the anode (4).

8. Electrolysis cell (1) according to any one of claims 1 to 5, characterized in that the circulation structure (5) has a height between 70 and 96% of the height of the anode (4).

9. Electrolysis cell (1) according to any one of claims 1 to 8, characterized in that the circulation structure (5) is a structure for supporting the anode (4) and / or supports the anode (4).

10. 10. Electrolysis cell (1) according to any one of the preceding claims, characterized in that the circulation structure (5) forms at least one downcomer in the anode chamber (2).

11. Electrolysis cell (1) according to claim 10, characterized in that said at least one downcomer has a V-shape.

12. Electrolysis device for chlor-alkali electrolysis, comprising a plurality of electrolysis cells (1) according to any one of claims 1 to 11.

13. Use of an electrolytic cell (1) according to any one of claims 1 to 11 or an electrolytic device according to claim 12 for chloralkali electrolysis.

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