Electrolysis chlorine production system

Abstract

The present invention provides an electrolytic chlorine production system, comprising a water softener, a salt dissolving tank, a descaling device, a concentrated brine tank, a filter, a first mixer, a dilute brine tank, an electrolytic cell and a sodium hypochlorite storage tank; the inlet of the water softener is used to connect to a water inlet pipe, and the outlet of the water softener is divided into two routes, one outlet of the water softener is communicated with the inlet of the first mixer, the other outlet of the water softener is communicated with the inlet of the salt dissolving tank, the outlet of the salt dissolving tank is communicated with the inlet of the concentrated brine tank, the outlet of the concentrated brine tank is communicated with the inlet of the filter, and the outlet of the filter is communicated with the inlet of the first mixer; the outlet of the first mixer is communicated with the inlet of the dilute brine tank, the outlet of the dilute brine tank is communicated with the inlet of the electrolytic cell, and the outlet of the electrolytic cell is communicated with the inlet of the sodium hypochlorite storage tank; the descaling device is arranged on a pipeline between the outlet of the salt dissolving tank and the inlet of the concentrated brine tank and / or on a pipeline between the outlet of the concentrated brine tank and the inlet of the filter.

Description

Technical Field

[0001] The present invention relates to the technical field of electrolytic chlorine production, in particular to an electrolytic chlorine production system. Background Art

[0002] Electrochlorination is a method of producing chlorine gas by electrolyzing water containing chloride ions. It is widely used to electrolyze seawater and salt water for anti-fouling treatment in coastal power plants and nuclear power plants, as well as for deactivating ship ballast water. In recent years, with the continued expansion of the application of electrochlorination equipment and the intensification of seawater pollution, the hardness of the water treated by electrochlorination has increased, and scaling of the electrochlorination plates has become increasingly serious, resulting in a significant increase in equipment energy consumption and maintenance costs.

[0003] Existing electrolytic salt water systems for producing sodium hypochlorite use only use a scale prevention method that softens the raw water without removing the hardness of the brine. Whether the electrolytic cell will scale depends on the quality of the salt. When using high-quality salt with high sodium chloride purity and low calcium and magnesium content, the electrolytic cell exhibits relatively good scaling. However, when using coarse salt with high impurities, particularly salt with high calcium and magnesium content, scaling becomes more severe, severely impacting normal cell operation, shortening the cell's cleaning cycle, and increasing the cell's maintenance workload. Summary of the Invention

[0004] The object of the present invention is to provide an electrolytic chlorine production system that can reduce the calcium and magnesium ion content in brine, reduce or avoid scaling of the electrolytic cell, thereby extending the cleaning cycle of the electrolytic cell and reducing the maintenance workload of the electrolytic cell.

[0005] The present invention provides an electrolytic chlorine production system, comprising a water softener, a salt dissolving tank, a descaling device, a concentrated brine tank, a filter, a first mixer, a diluted brine tank, an electrolytic cell and a sodium hypochlorite storage tank;

[0006] The inlet of the water softener is used to connect to the water inlet pipe, and the outlet of the water softener is divided into two routes, one outlet of the water softener is communicated with the inlet of the first mixer, and the other outlet of the water softener is communicated with the inlet of the salt dissolving tank, the outlet of the salt dissolving tank is communicated with the inlet of the concentrated brine tank, the outlet of the concentrated brine tank is communicated with the inlet of the filter, and the outlet of the filter is communicated with the inlet of the first mixer; the outlet of the first mixer is communicated with the inlet of the dilute brine tank, the outlet of the dilute brine tank is communicated with the inlet of the electrolytic cell, and the outlet of the electrolytic cell is communicated with the inlet of the sodium hypochlorite storage tank; the descaling device is arranged on the pipeline between the outlet of the salt dissolving tank and the inlet of the concentrated brine tank and / or on the pipeline between the outlet of the concentrated brine tank and the inlet of the filter.

[0007] Furthermore, the descaling device includes a second mixer, which is arranged on the pipeline between the outlet of the salt dissolving tank and the inlet of the concentrated brine tank; the electrolytic chlorine production system also includes a return pipeline, the two ends of which are respectively connected to the outlet of the sodium hypochlorite storage tank and the inlet of the second mixer.

[0008] Furthermore, the descaling device includes an electrochemical descaler, which is arranged on a pipeline between the outlet of the salt dissolving tank and the inlet of the concentrated brine tank.

[0009] Furthermore, the descaling device includes a second mixer and an electrochemical descaling device, and the second mixer and the electrochemical descaling device are both arranged on the pipeline between the outlet of the salt dissolving tank and the inlet of the concentrated brine tank; the electrolytic chlorine production system also includes a return pipeline, and the two ends of the return pipeline are respectively connected to the outlet of the sodium hypochlorite storage tank and the inlet of the second mixer.

[0010] Furthermore, the second mixer and the electrochemical descaler are arranged in series.

[0011] Furthermore, the second mixer and the electrochemical descaling device are arranged in parallel, and a switch valve is provided on the branch where the second mixer is located and the branch where the electrochemical descaling device is located.

[0012] Furthermore, a flow regulating valve is provided on the reflux pipeline, a calcium and magnesium ion concentration detector is provided on the pipeline between the outlet of the dilute brine tank and the inlet of the electrolytic cell, and the flow regulating valve is signal-connected to the calcium and magnesium ion concentration detector.

[0013] Furthermore, the electrochemical descaler and the electrolytic cell share the same power supply.

[0014] Furthermore, the descaling device includes a hydrocyclone, which is arranged on a pipeline between the outlet of the concentrated brine tank and the inlet of the filter.

[0015] Furthermore, the filter is a PP cotton security filter.

[0016] The electrolytic chlorine production system provided by the present invention divides the outlet of a water softener into two routes, one of which is connected to a salt dissolving tank, thereby dissolving the solid salt in the salt dissolving tank. The highly concentrated brine produced after dissolution is descaled by a descaling device and a filter, and then mixed with softened water output from the other outlet of the water softener in a first mixer to form a dilute brine solution. The dilute brine solution then enters the electrolytic cell for electrolytic chlorine production. Because the calcium and magnesium ions in the brine are removed by the descaling device and the filter, the calcium and magnesium ion content in the brine electrolyzed by the electrolytic cell can be reduced, reducing or avoiding the occurrence of scaling in the electrolytic cell, thereby extending the cleaning cycle of the electrolytic cell, reducing the maintenance workload of the electrolytic cell, and even making the electrolytic cell cleaning and maintenance-free during the life cycle of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the electrolytic chlorine production system in the first embodiment of the present invention.

[0018] Figure 2 Schematic diagram of the structure of the electrolytic chlorine production system in the second embodiment of the present invention.

[0019] Figure 3 Schematic diagram of the structure of the electrolytic chlorine production system in the third embodiment of the present invention.

[0020] Figure 4 Schematic diagram of the structure of the electrolytic chlorine production system in the fourth embodiment of the present invention.

[0021] Figure 5 Schematic diagram of the structure of the electrolytic chlorine production system in the fifth embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0023] The terms "first", "second", "third", "fourth", etc. in the description and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0024] like Figure 1 As shown, the electrolytic chlorine production system provided by the embodiment of the present invention includes a water softener 1, a salt dissolving tank 2, a descaling device 3, a concentrated brine tank 4, a filter 5, a first mixer 6, a diluted brine tank 7, an electrolytic cell 8 and a sodium hypochlorite storage tank 9;

[0025] The inlet of the water softener 1 is used to connect to the water inlet pipe 10, and the outlet of the water softener 1 is divided into two routes. One outlet of the water softener 1 is communicated with the inlet of the first mixer 6, and the other outlet of the water softener 1 is communicated with the inlet of the salt dissolving tank 2, the outlet of the salt dissolving tank 2 is communicated with the inlet of the concentrated brine tank 4, the outlet of the concentrated brine tank 4 is communicated with the inlet of the filter 5, and the outlet of the filter 5 is communicated with the inlet of the first mixer 6; the outlet of the first mixer 6 is communicated with the inlet of the dilute brine tank 7, the outlet of the dilute brine tank 7 is communicated with the inlet of the electrolytic cell 8, and the outlet of the electrolytic cell 8 is communicated with the inlet of the sodium hypochlorite storage tank 9; the descaling device 3 is arranged on the pipeline between the outlet of the salt dissolving tank 2 and the inlet of the concentrated brine tank 4 and / or on the pipeline between the outlet of the concentrated brine tank 4 and the inlet of the filter 5.

[0026] Specifically, the electrolytic chlorine production system provided in this embodiment divides the outlet of the water softener 1 into two routes, one of which is connected to the salt dissolving tank 2, thereby dissolving the solid salt in the salt dissolving tank 2. The highly concentrated brine produced after the dissolution is descaled by the descaling device 3 and the filter 5, and then mixed with the softened water output from the other outlet of the water softener 1 in the first mixer 6 to form a dilute brine solution. The dilute brine solution then enters the electrolytic cell 8 for electrolytic chlorine production. Since the calcium and magnesium ions in the brine are removed by the descaling device 3 and the filter 5, the calcium and magnesium ion content in the electrolytic brine of the electrolytic cell 8 can be reduced, reducing or avoiding the occurrence of scaling in the electrolytic cell 8, thereby extending the cleaning cycle of the electrolytic cell 8, reducing the maintenance workload of the electrolytic cell 8, and even making the electrolytic cell 8 free of cleaning and maintenance during the life cycle of the electrode.

[0027] like Figure 1 As shown, as an embodiment, the descaling device 3 includes a second mixer 31, which is arranged on the pipeline between the outlet of the salt dissolving tank 2 and the inlet of the concentrated brine tank 4; the electrolytic chlorine production system also includes a return pipeline 11, and the two ends of the return pipeline 11 are respectively connected to the outlet of the sodium hypochlorite storage tank 9 and the inlet of the second mixer 31.

[0028] Specifically, the electrolytic chlorine production system operates as follows: industrial water or domestic water enters the water softener 1 through the water inlet pipe 10. The softener 1 removes calcium and magnesium ions from the water to produce softened water. The resulting softened water is divided into two paths, one of which enters the salt dissolving tank 2 to dissolve the solid salt in the salt dissolving tank 2 into a saturated brine solution. Because the solid salt contains some soluble calcium and magnesium ions, the saturated brine solution will contain calcium and magnesium ions. The sodium hypochlorite solution produced by electrolysis contains OH -ions, sodium hypochlorite solution is alkaline, so after the sodium hypochlorite solution generated by electrolysis is refluxed to the second mixer 31 through the reflux pipe 11, the saturated brine solution can be mixed with the refluxed sodium hypochlorite solution in the second mixer 31, and the mixed solution enters the concentrated brine tank 4 for full reaction. - Ions can be combined with Mg 2+ The reaction generates Mg(OH)2 precipitation, which can also make HCO3 in the solution - Converted to CO3 2- , thereby generating CaCO3 precipitation, thereby removing calcium and magnesium ions from the saturated brine solution. The concentrated brine after mixing and fully reacting is filtered through a filter 5 to filter the generated precipitate, thereby achieving the purpose of removing calcium and magnesium ions from the solution. The concentrated brine from which calcium and magnesium ions have been removed is mixed with softened water in a first mixer 6 in a proportion to form a dilute brine solution, which then enters an electrolytic cell 8 to produce a sodium hypochlorite solution through electrolysis. The generated sodium hypochlorite solution is stored in a sodium hypochlorite storage tank 9, a portion of which is added to the dosing point where sodium hypochlorite is required, and the remaining portion is mixed with the saturated brine as described above to precipitate calcium and magnesium ions.

[0029] This embodiment utilizes the sodium hypochlorite solution generated by electrolysis to react with the saturated brine solution to remove calcium and magnesium ions from the saturated brine solution. This not only has a simple structure but also does not require the addition of additional reagents, thereby saving equipment costs and equipment space.

[0030] like Figure 1 As shown, as an embodiment, a flow regulating valve 34 is provided on the reflux pipeline 11, a calcium and magnesium ion concentration detector 35 is provided on the pipeline between the outlet of the dilute brine tank 7 and the inlet of the electrolytic cell 8, and the flow regulating valve 34 is signal-connected to the calcium and magnesium ion concentration detector 35.

[0031] Specifically, since different types of solid salts may be added to the salt dissolving tank 2, and the content of calcium and magnesium ions in different types of solid salts will also be different, the concentration of calcium and magnesium ions in the saturated brine solution formed by the dissolution will also be different. The calcium and magnesium ion concentration detector 35 is used to detect the concentration of calcium and magnesium ions in the brine entering the electrolytic cell 8. When the concentration of calcium and magnesium ions in the brine entering the electrolytic cell 8 is high, the flow regulating valve 34 is controlled to increase the valve opening so that more sodium hypochlorite solution flows back to the second mixer 31, thereby more completely removing the calcium and magnesium ions in the saturated brine solution; conversely, when the concentration of calcium and magnesium ions in the brine entering the electrolytic cell 8 is very low, the flow regulating valve 34 can be controlled to decrease the valve opening, thereby reducing the reflux amount of sodium hypochlorite solution, thereby increasing the output of sodium hypochlorite solution.

[0032] like Figure 2As shown, as another embodiment, the descaling device 3 includes an electrochemical descaling device 32 , which is arranged on a pipeline between the outlet of the salt dissolving tank 2 and the inlet of the concentrated brine tank 4 .

[0033] Specifically, the electrochemical descaling device 32 is a device that generates OH by electrolyzing salt water. - ions to remove calcium and magnesium ions. When working, the cathode electrolysis of the electrochemical descaling device 32 produces OH - Ions, the anode of the electrochemical descaling device 32 electrolyzes to produce chlorine (the working principle of the electrochemical descaling device 32 is similar to that of the electrolytic cell 8), and the cathode produces OH - Ions can be combined with Mg 2+ The reaction generates Mg(OH)2 precipitation, which can also make HCO3 in the solution - Converted to CO3 2- , thereby generating CaCO3 precipitation, thereby removing calcium and magnesium ions from the saturated brine solution (calcium and magnesium ions will be adsorbed on the cathode of the electrochemical descaling device 32). Since the electrolytic medium of the electrochemical descaling device 32 is saturated brine, its electrical conductivity is high, and thus the energy consumption of the electrochemical descaling device 32 can be reduced. Moreover, since the anode of the electrochemical descaling device 32 undergoes a chlorine evolution reaction, which is coupled with the chlorine evolution process of the electrolytic cell 8, it can increase the output of the sodium hypochlorite solution and improve the efficiency of electrolytic chlorine production.

[0034] As an embodiment, the electrochemical descaling device 32 and the electrolytic cell 8 share the same power supply. Since both the electrochemical descaling device 32 and the electrolytic cell 8 are electrolytic devices and both use a DC power supply, they can use the same power supply. By sharing the same power supply for the electrochemical descaling device 32 and the electrolytic cell 8, the use of equipment such as rectifiers and power distribution cabinets can be reduced, thereby reducing the number of equipment, cost, and occupied space.

[0035] As an embodiment, the scale deposited on the cathode of the electrochemical descaler 32 can be removed by a reversal method or a mechanical method.

[0036] like Figure 4 As shown, as another embodiment, the descaling device 3 includes a second mixer 31 and an electrochemical descaling device 32, and the second mixer 31 and the electrochemical descaling device 32 are both arranged on the pipeline between the outlet of the salt dissolving tank 2 and the inlet of the concentrated brine tank 4; the electrolytic chlorine production system also includes a return pipeline 11, and the two ends of the return pipeline 11 are respectively connected to the outlet of the sodium hypochlorite storage tank 9 and the inlet of the second mixer 31.

[0037] like Figure 4As shown, as an embodiment, the second mixer 31 and the electrochemical descaling device 32 are arranged in series; wherein, the second mixer 31 can be arranged upstream of the electrochemical descaling device 32, or downstream of the electrochemical descaling device 32. By combining the effects of the electrochemical descaling device 32 and the reflux of the sodium hypochlorite solution, the removal efficiency of calcium and magnesium ions is further improved.

[0038] like Figure 5 As shown, as another embodiment, the second mixer 31 and the electrochemical descaling device 32 are arranged in parallel, and a switch valve 33 is provided on the branch where the second mixer 31 is located and the branch where the electrochemical descaling device 32 is located. Specifically, by arranging the second mixer 31 and the electrochemical descaling device 32 in parallel, and providing the switch valves 33 on the branch where the second mixer 31 is located and the branch where the electrochemical descaling device 32 is located, by controlling the opening and closing of each switch valve 33, the second mixer 31 and the electrochemical descaling device 32 can work simultaneously or separately, so that different working modes can be used according to different working conditions to improve working efficiency.

[0039] like Figure 3 As shown, as another embodiment, the descaling device 3 includes a hydrocyclone 36 , which is arranged on the pipeline between the outlet of the brine tank 4 and the inlet of the filter 5 .

[0040] Specifically, the hydrocyclone 36 is a grading device that uses centrifugal force to accelerate the sedimentation of impurities. By arranging the hydrocyclone 36 on the pipeline between the outlet of the brine tank 4 and the inlet of the filter 5, the sedimentation rate of the calcium and magnesium precipitates can be further increased, thereby further improving the removal efficiency of calcium and magnesium ions.

[0041] As an embodiment, the filter 5 is a PP cotton security filter.

[0042] Specifically, the PP cotton security filter is a precision filter, which not only has high filtration accuracy, small filtration resistance, strong pollution interception ability and long service life, but also is low in price and low in cost, which can reduce operation and maintenance costs.

[0043] The electrolytic chlorine production system provided in an embodiment of the present invention divides the outlet of the water softener 1 into two routes, one of which is connected to the salt dissolving tank 2, thereby dissolving the solid salt in the salt dissolving tank 2. The highly concentrated brine produced after the dissolution is descaled by the descaling device 3 and the filter 5, and then mixed with the softened water output from the other outlet of the water softener 1 in the first mixer 6 to form a dilute brine solution. The dilute brine solution then enters the electrolytic cell 8 for electrolytic chlorine production. Since the calcium and magnesium ions in the brine are removed by the descaling device 3 and the filter 5, the calcium and magnesium ion content in the brine electrolyzed by the electrolytic cell 8 can be reduced, reducing or avoiding the occurrence of scaling in the electrolytic cell 8, thereby extending the cleaning cycle of the electrolytic cell 8, reducing the maintenance workload of the electrolytic cell 8, and even making the electrolytic cell 8 free of cleaning and maintenance during the life cycle of the electrode.

[0044] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A chlorine electrolysis system, characterized in that: It comprises a water softener (1), a salt dissolving tank (2), a descaling device (3), a concentrated brine tank (4), a filter (5), a first mixer (6), a diluted brine tank (7), an electrolytic cell (8) and a sodium hypochlorite storage tank (9); The inlet of the water softener (1) is used to connect to the water inlet pipe (10), and the outlet of the water softener (1) is divided into two ways, one outlet of the water softener (1) is communicated with the inlet of the first mixer (6), and the other outlet of the water softener (1) is communicated with the inlet of the salt dissolving tank (2), the outlet of the salt dissolving tank (2) is communicated with the inlet of the concentrated brine tank (4), the outlet of the concentrated brine tank (4) is communicated with the inlet of the filter (5), and the outlet of the filter (5) is communicated with the inlet of the first mixer (6). The inlet of the first mixer (6) is communicated with the inlet of the dilute brine tank (7), the outlet of the dilute brine tank (7) is communicated with the inlet of the electrolytic cell (8), and the outlet of the electrolytic cell (8) is communicated with the inlet of the sodium hypochlorite storage tank (9); the descaling device (3) is arranged on the pipeline between the outlet of the salt dissolving tank (2) and the inlet of the concentrated brine tank (4) and / or on the pipeline between the outlet of the concentrated brine tank (4) and the inlet of the filter (5); The descaling device (3) includes a second mixer (31), which is arranged on the pipeline between the outlet of the salt dissolving tank (2) and the inlet of the concentrated brine tank (4); the electrolytic chlorine production system also includes a return pipeline (11), the two ends of which are respectively connected to the outlet of the sodium hypochlorite storage tank (9) and the inlet of the second mixer (31); the return pipeline (11) is provided with a flow regulating valve (34), and the pipeline between the outlet of the diluted brine tank (7) and the inlet of the electrolytic cell (8) is provided with a calcium and magnesium ion concentration detector (35), and the flow regulating valve (34) is connected to the calcium and magnesium ion concentration detector (35) for signal connection.

2. The electrolytic chlorine production system according to claim 1, characterized in that: The descaling device (3) comprises an electrochemical descaling device (32), and the electrochemical descaling device (32) is arranged on a pipeline between the outlet of the salt dissolving tank (2) and the inlet of the concentrated brine tank (4).

3. The electrolytic chlorine production system according to claim 2, characterized in that: The second mixer (31) and the electrochemical descaling device (32) are arranged in series.

4. The electrolytic chlorine production system according to claim 2, characterized in that: The second mixer (31) and the electrochemical descaling device (32) are arranged in parallel, and a switch valve (33) is provided on the branch where the second mixer (31) is located and the branch where the electrochemical descaling device (32) is located.

5. The electrolytic chlorine production system according to any one of claims 2 to 4, characterized in that: The electrochemical descaler (32) and the electrolytic cell (8) share the same power supply.

6. The electrolytic chlorine production system according to claim 1, characterized in that: The descaling device (3) comprises a hydrocyclone (36), and the hydrocyclone (36) is arranged on a pipeline between the outlet of the concentrated brine tank (4) and the inlet of the filter (5).

7. The electrolytic chlorine production system according to claim 1, characterized in that: The filter (5) is a PP cotton security filter.

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