Hydraulic drive type rotating cathode electrochemical seawater chlorine production device and application method thereof

Abstract

The invention discloses a hydraulic drive type rotating cathode electrochemical seawater chlorine production device and an application method thereof.The device comprises a shell, a hydraulic impeller and an electrode set, the shell is provided with a water inlet, a water outlet and a sewage draining exit, a rotating shaft conductive connecting rod is installed in the center of the shell, and the hydraulic impeller and a disc cathode are fixed to the rotating shaft conductive connecting rod; the fixed anodes are distributed on the two sides of the rotary disc cathode at intervals, the end angles of the fixed anodes penetrate through the shell through fixed conductive connecting rods and are connected with the positive electrode and the negative electrode of an external direct-current electrolysis power source, a water inlet of the shell right faces the hydraulic impeller, and the hydraulic impeller is driven by water inlet kinetic energy to drive the coaxial disc cathode to rotate. And the disc cathode and the fixed scraper form relative motion so as to remove a surface scale layer. The water power impeller can be driven to rotate through water inlet kinetic energy to achieve removal of cathode surface scale, the efficiency and operation stability of an electrolysis system are improved, and the electrode surface scale can be removed in time without additionally arranging a rotating motor.

Description

Technical Field

[0001] The invention relates to a hydraulically driven rotating cathode electrochemical seawater chlorine production device and an application method thereof, belonging to the field of environmental protection equipment. Background Art

[0002] At present, the design of coastal power stations adopts seawater direct cooling circulating water system as the cold source of power stations, and simultaneously designs the electrolytic seawater chlorination system to prepare biocides to inhibit marine organisms from attaching to the circulating water heat exchange system equipment. However, due to the presence of high hardness ions in seawater, the electrolytic seawater chlorination device that has been put into practical application is prone to calcium and magnesium precipitation scaling on the cathode surface after a period of operation. The growing scaling will affect the normal ion separation of the cathode plate, thereby reducing the chemical reaction effect. At present, the main methods for cathode descaling are the following manual cleaning method, acid cleaning method, pulse current method or ultrasonic method, and reversal method. However, these methods have many problems. Frequent shutdown and cleaning have a certain impact on the normal operation of production. The use of chemical reagents is prone to secondary pollution, which damages the normal service life of the equipment and also increases maintenance costs and equipment investment.

[0003] As an important physical method of the electrochemical treatment descaling device, the scraper mainly forms a relative motion with the cathode to timely remove the scale on the electrode surface, and can complete the cleaning of the cathode surface without stopping the equipment, thereby improving the cleaning effect and work efficiency as a whole. CN201480028280 discloses a water electrolysis system with a rotating disc cathode and an automatic cathode cleaner, wherein a fixed cathode cleaning assembly is deployed between the rotating cathodes, and the fixed cathode cleaning assembly is in contact with each surface of the rotating cathode. When the electrolysis device is working, the fixed cathode cleaning assembly and the rotating disc cathode are in continuous contact, thereby fully removing the scale deposited on the cathode surface during the electrolysis process. However, the system continuously consumes electricity to drive the working electrode to rotate during operation, which increases the operation and maintenance cost investment. CN202111307567 discloses an electrochemical water treatment device with a descaling function, in which the rotating shaft in the cylinder is driven to rotate by an electrode, a cathode is fixed at the center of the extended circular plate of the rotating shaft, the cathode is symmetrically arranged at the edge of the extended circular plate, and an electrode scraper is fixed on the inner wall of the cylinder. The electrode drives the cathode and the fixed scraper to form a relative movement, thereby completing the descaling of the cathode surface. However, the system is limited by the extended disc, the number of cathodes and the working area design are limited, and it is impossible to complete the double-sided descaling of the cathode surface. Summary of the invention

[0004] In view of the above-mentioned technical problems existing in the prior art, the purpose of the present application is to provide a hydraulically driven rotating cathode electrochemical seawater chlorine production device and an application method thereof.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A hydraulically driven rotating cathode electrochemical seawater chlorine production device comprises a shell, a hydraulic impeller and an electrode group, wherein the electrode group is arranged inside the shell, the electrode group comprises a fixed anode and a disk cathode, the fixed anode is connected to a fixed conductive connecting rod and the fixed conductive connecting rod extends outside the shell, the center of the disk cathode is fixedly connected to a rotating shaft conductive connecting rod and the rotating shaft conductive connecting rod extends outside the shell, and is connected to the positive and negative electrodes of an external DC power supply by wires respectively; fixed scrapers are arranged on both sides of the disk cathode, the hydraulic impeller is coaxially arranged with the disk cathode and fixedly arranged on the rotating shaft conductive connecting rod, the shell is provided with a water inlet, a water outlet and a sewage outlet, and the water outlet and the sewage outlet are arranged at the upper part and the lower part of the shell respectively. The installation position of the hydraulic impeller is directly opposite to the water inlet, so that the hydraulic impeller can be directional rotated around the rotating shaft conductive connecting rod under the impact of the kinetic energy of the incoming water, and drive the coaxial disk cathode to rotate together, and the disk cathode rotates relative to the fixed scraper, so that the dirt on the electrode surface can be cleaned in time while the electrolysis chlorine is produced.

[0007] In the above scheme, the hydraulic impeller is made of 316L stainless steel, high-density plastic or nylon, etc. The hydraulic impeller includes a water-receiving impeller blade and a turntable. The water-receiving impeller blade is centrally symmetrically located on the turntable, and the water-receiving impeller blade forms an acute angle with the turntable plane.

[0008] In the above scheme, the rotating disk is fixed by a conductive connecting rod passing through the rotating shaft, and the rotating disk drives the coaxial circular cathode to rotate through the conductive connecting rod.

[0009] In the above scheme, the fixed anode is a boron-doped diamond film (BDD) electrode, a shape-stable anode (DSA), a PbO2 electrode or a Ti4O7 electrode, etc., the disc cathode material is pure nickel, titanium plate or 316L stainless steel, the fixed conductive connecting rod and the rotating shaft conductive connecting rod are made of carbon steel or stainless steel, and the fixed scraper is made of 316L stainless steel.

[0010] Furthermore, the number of the fixed anodes and the disc cathodes are both multiple, and the multiple disc cathodes are coaxially and evenly distributed on the shaft conductive connecting rod, and the fixed anodes and the disc cathodes are alternately arranged one by one.

[0011] Furthermore, the spacing between the fixed anode and the disk cathode is 10-50 mm, preferably 15-20 mm. The spacing between the cathode and anode will affect the electrolysis efficiency. If the electrode spacing is too small, it will easily lead to electrode breakdown. If the electrode spacing is too large, the current efficiency will be relatively low.

[0012] Furthermore, the fixed anode is composed of two symmetrical half-sheet structures with a gap in the middle, and the two half-sheet structures are arranged correspondingly in the semicircular areas on both sides of the disc cathode, and the half-sheet structure and the disc cathode are parallel to each other. The fixed anode of the present application is provided with two half-sheet structures, which has the advantage of convenient disassembly and installation. If the structure of the fixed anode is a whole piece, then each time the anode or cathode is replaced, the entire electrode group needs to be removed, and the disassembly and installation is relatively complicated.

[0013] Furthermore, two end corners of the half-piece structure are respectively connected to fixed conductive connecting rods, which are then penetrated and fixed on the shell.

[0014] Furthermore, an impeller chamber is docked on the outer side of the shell side, the water inlet is tangentially arranged on the impeller chamber, one end of the shaft conductive connecting rod passes through the outside of the shell and a rotary seal is arranged on the side wall of the impeller chamber, and the hydraulic impeller is arranged on the shaft conductive connecting rod in the impeller chamber.

[0015] Furthermore, the fixed scraper is fixedly mounted on the inner wall of the shell, and the spacing between the fixed scraper and the disc cathode is 0.2-0.8 mm.

[0016] Furthermore, the size of the hydraulic impeller and the arrangement of the impeller can be adjusted according to the hydraulic conditions of the water inlet and the water quality.

[0017] The present invention also provides an application method of the hydraulically driven rotating cathode electrochemical seawater chlorine production device, comprising: seawater or seawater dilution enters the shell from the water inlet, impacts the hydraulic impeller to rotate, drives the coaxially connected disc cathode to rotate accordingly, after the external DC power supply is started, the current is transmitted to the disc cathode and the fixed anode surface respectively through the shaft conductive connecting rod and the fixed conductive connecting rod to trigger reduction and oxidation reactions, wherein the fixed anode activates the chloride ions and water molecules in the water to generate active oxidizing species, the disc cathode activates the water molecules to generate hydrogen, and at the same time, a local alkaline environment is formed on the surface of the disc cathode, which reacts with the hardness ions in the seawater, and gradually nucleates and precipitates near the surface of the disc cathode to become scale; through the relative movement between the disc cathode and the fixed scraper, the scale layer on the surface of the disc cathode is continuously removed, the fallen scale stains are scraped off and deposited on the bottom of the shell, and discharged through the sewage outlet, and the seawater after the electrolysis reaction is discharged through the water outlet to the downstream storage tank for use.

[0018] In the above scheme, the electrolysis current density of the device is 1000-3000A / m 2 , the chloride concentration required for electrolysis of seawater by the device is at least 3000 mg / L;

[0019] In the above scheme, the flow rate of electrolyzing seawater by the device is 500-2000 L / h, and the effective chlorine concentration in the seawater after electrolysis is 5-300 mg / L.

[0020] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: the present invention provides a hydraulically driven rotating cathode electrochemical seawater chlorine production device, in which a hydraulic impeller and a disc cathode are coaxially arranged in parallel, and the kinetic energy of the incoming water is used to drive the rotating disc cathode and the fixed scraper to move relative to each other, thereby achieving low-energy consumption and timely removal of dirt on the cathode surface, and effectively improving the working efficiency and stability of the system device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front view half-section structure schematic diagram of the hydraulic driven rotating cathode electrochemical seawater chlorine production device of the present invention;

[0022] Figure 2 It is a schematic diagram of the top view of the structure of the hydraulically driven rotating cathode electrochemical seawater chlorine production device of the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0024] Example: Control Figure 1-Figure 2

[0025] A hydraulically driven rotating cathode electrochemical seawater chlorine production device comprises a housing 1, a hydraulic impeller 7 and an electrode group, wherein the electrode group is arranged inside the housing 1, and the electrode group comprises a fixed anode 6 and a disk cathode 5, wherein the fixed anode 6 is connected to a fixed conductive connecting rod 8 and the fixed conductive connecting rod 8 extends outside the housing, and the center of the disk cathode 5 is fixedly connected to a rotating shaft conductive connecting rod 9 and the rotating shaft conductive connecting rod 9 extends outside the housing, and is connected to the positive and negative electrodes of an external DC power supply by wires, respectively. The hydraulic impeller 7 is coaxially arranged with the disk cathode 5 and fixedly arranged on the rotating shaft conductive connecting rod 9, and the housing 1 is provided with a water inlet 2, a water outlet 3 and a sewage outlet 4, and the water outlet 3 and the sewage outlet 4 are arranged at the upper part and the lower part of the housing 1, respectively.

[0026] The number of the fixed anode 6 and the disc cathode 5 is multiple, and the multiple disc cathodes 5 are coaxially and evenly spaced on the rotating shaft conductive connecting rod 9, and the fixed anode 6 and the disc cathode 5 are alternately arranged one by one, and the interval between the fixed anode 6 and the disc cathode 5 is 10-50mm. The fixed anode 6 is composed of two symmetrical half-sheet structures with a gap in the middle, and the two half-sheet structures are correspondingly arranged in the semicircular areas on both sides of the disc cathode, and the half-sheet structures and the disc cathode 5 are parallel to each other.

[0027] Comparison Figure 1 The two end corners of the half-piece structure are respectively connected to fixed conductive connecting rods 8, and the fixed conductive connecting rods 8 are then penetrated and fixed on the shell 1.

[0028] Fixed scrapers 10 are provided on both sides of the disk cathode 5. The fixed scrapers 10 are fixedly mounted on the inner wall of the housing 1. The spacing between the fixed scrapers 10 and the disk cathode 5 is 0.2-0.8 mm.

[0029] Comparison Figure 2 The outer side of the shell 1 is butt-jointed with an impeller chamber, the water inlet 2 is tangentially arranged on the impeller chamber, one end of the shaft conductive connecting rod 9 passes through the outside of the shell and is then rotatably sealed on the side wall of the impeller chamber, and the hydraulic impeller 7 is arranged on the shaft conductive connecting rod 9 in the impeller chamber. The installation position of the hydraulic impeller 7 is directly opposite to the water inlet 2, so that the hydraulic impeller 7 can be directional rotated around the shaft conductive connecting rod 9 under the impact of the kinetic energy of the incoming water, and drive the coaxial disc cathode 5 to rotate together. When the disc cathode 5 rotates, it moves relative to the fixed scraper 10, so that the dirt on the electrode surface can be cleaned in time while the electrolysis chlorine is produced.

[0030] Embodiment 1:

[0031] A hydraulically driven rotating cathode electrochemical seawater chlorine production device, the structure of which is shown in Figure 1-2 , including a housing 1 made of carbon steel, a hydraulic impeller 7 and an anode and cathode electrode group embedded in the housing, the side, upper part and lower part of the housing are respectively provided with a water inlet 2, a water outlet 3 and a sewage outlet 4, the anode and cathode electrode group includes 15 fixed anodes 6, 14 disc cathodes 5 and 15 fixed scrapers 10, each fixed anode 6 is composed of two symmetrical half-sheet structures with a gap in the middle, and the two half-sheet structures are arranged correspondingly on the two sides of the semicircular area of ​​the same surface of the disc cathode 5. The interval between the fixed anode 6 and the disc cathode 5 is 20mm, the interval between the fixed scraper 10 and the disc cathode 5 is 0.2mm, the hydraulic impeller 7 is connected to the front of the water inlet 2, the fixed scraper 10 is close to the surface of the disc cathode 5, the disc cathode 5 is a 316L stainless steel electrode, the fixed anode 6 is a DSA electrode purchased from Baoji Qixin Titanium Co., Ltd., the electrode composition is Ti / IrO2-RuO2 electrode, and the hydraulic impeller 7 is made of high-density plastic.

[0032] Embodiment 2:

[0033] A water scraper type electrochemical seawater chlorine production and descaling device, the structure of which is the same as that of Example 1, and the difference is only in the following features:

[0034] The cathode and cathode electrode group includes 10 fixed anodes 6, 9 disc cathodes 5 and 10 fixed scrapers 10. Each fixed anode 6 is composed of two symmetrical half-sheet structures with a gap in the middle, and the two half-sheet structures are arranged correspondingly on the two semicircular areas on the same side of the disc cathode 5. The interval between the fixed anode 6 and the disc cathode 5 is 15 mm, and the interval between the fixed scraper 10 and the disc cathode 5 is 0.4 mm.

[0035] The disk cathode 5 is a titanium plate electrode, and the fixed anode 6 is a BDD electrode, which are purchased from Baoji Qixin Titanium Co., Ltd.

[0036] The working principle of the above technical solution is:

[0037] When seawater or seawater dilution enters the housing 1 from the water inlet, the hydraulic impeller 7 is impacted to rotate, driving the coaxially connected disc cathode 5 to rotate accordingly. After the DC power supply is started, the current is transmitted to the fixed anode 6 and the surface of the disc cathode 5 to trigger reduction and oxidation reactions, wherein the fixed anode 6 activates chloride ions and water molecules in the water to generate active oxidative species, such as hypochlorite ions (ClO - ), active oxygen molecules (·OH), etc., the disk cathode 5 activates water molecules to produce hydrogen. At the same time, a local alkaline environment is formed on the surface of the disk cathode 5, which reacts with hardness ions such as calcium and magnesium in seawater, and gradually nucleates and precipitates into scale near the cathode surface. The disk cathode 5 is relatively moved with the fixed scraper 10, so that the scale layer on the surface of the disk cathode 5 is continuously removed, and the fallen scale stains are scraped off and deposited to the bottom of the device shell. After a period of time, the dirt deposited at the bottom of the device shell is emptied, and the seawater after the electrolysis reaction is discharged to the downstream storage tank through the top drain port 3 for use. This set of devices can effectively ensure the long-term stable operation of the electrolysis system and extend the cycle required for dirt cleaning and equipment maintenance and downtime.

[0038] Application Example 1:

[0039] The device structure described in Example 1 or Example 2 was used to perform a seawater electrolysis experiment. The conditions for producing chlorine by electrolysis of seawater were: seawater temperature 30°C, chloride concentration 15822 mg / L, current density 1000 A / m 2 The water inlet flow rate is 1500L / h. Water quality detection meters are designed at the inlet and outlet to measure the active chlorine and TDS before and after treatment. The electrolysis reaction time is 12h. The energy consumption electrolysis voltage value is read to calculate the energy consumption. The scale deposited at the bottom of the device is collected, and the TDS removal rate and scale removal rate are calculated.

[0040] Example 1 Example 2 Active chlorine concentration in effluent mg / L 236.8 175.2 <![CDATA[Chlorine production energy consumption (kW·h·g -1 )]]> 6.33 8.56 TDS removal rate % 45.6 40.7 Scale removal rate % 87.2 81.1

[0041] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as being limited to the specific forms described in the embodiments.

Claims

1. A hydraulically driven rotating cathode electrochemical seawater chlorine production device, characterized in that: The invention comprises a housing (1), a hydraulic impeller (7) and an electrode group, wherein the electrode group is arranged inside the housing (1), the electrode group comprising a fixed anode (6) and a disc cathode (5), the fixed anode (6) being connected to a fixed conductive connecting rod (8) and the fixed conductive connecting rod (8) extending outside the housing, the center of the disc cathode (5) being fixedly connected to a rotating shaft conductive connecting rod (9) and the rotating shaft conductive connecting rod (9) extending outside the housing, and being connected to the positive and negative electrodes of an external DC power supply by wires respectively; fixed scrapers (10) are provided on both sides of the disc cathode (5), and the hydraulic impeller (7) is provided with a fixed scraper (10) on both sides of the disc cathode (5). (7) is coaxially arranged with the disk cathode (5) and fixedly arranged on the rotating shaft conductive connecting rod (9), the housing (1) is provided with a water inlet (2), a water outlet (3) and a sewage outlet (4), the installation position of the hydraulic impeller (7) is directly opposite to the water inlet (2), so that the hydraulic impeller (7) can rotate around the rotating shaft conductive connecting rod (9) in a directional manner under the impact of the kinetic energy of the incoming water, and drive the coaxial disk cathode (5) to rotate together, and when the disk cathode (5) rotates, it moves relative to the fixed scraper (10), so that the dirt on the electrode surface can be cleaned in time while the electrolysis chlorine is produced.

2. A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in claim 1, characterized in that: The number of the fixed anode (6) and the disc cathode (5) are both multiple, and the multiple disc cathodes (5) are coaxially evenly spaced and distributed on the rotating shaft conductive connecting rod (9), and the fixed anode (6) and the disc cathode (5) are alternately spaced and arranged one by one.

3. A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in claim 2, characterized in that: The spacing between the fixed anode (6) and the disk cathode (5) is 10-50 mm, preferably 15-20 mm.

4. A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in claim 1, characterized in that: The fixed anode (6) is composed of two symmetrical half-sheet structures with a gap in between, the two half-sheet structures being arranged correspondingly in the semicircular regions on both sides of the disk cathode, and the half-sheet structures and the disk cathode (5) are parallel to each other.

5. A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in claim 4, characterized in that: The two end corners of the half-piece structure are respectively connected to fixed conductive connecting rods (8), and the fixed conductive connecting rods (8) are then penetrated and fixed on the housing (1).

6. A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in claim 1, characterized in that: An impeller chamber is butt-jointedly arranged on the outer side of the side of the shell (1); the water inlet (2) is tangentially arranged on the impeller chamber; one end of the rotating shaft conductive connecting rod (9) passes through the outside of the shell and is then rotary sealed on the side wall of the impeller chamber; and the hydraulic impeller (7) is arranged on the rotating shaft conductive connecting rod (9) in the impeller chamber.

7. A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in claim 1, characterized in that: The water outlet (3) and the sewage outlet (4) are respectively arranged at the upper part and the lower part of the shell (1).

8. The hydraulically driven rotating cathode electrochemical seawater chlorine production device according to claim 1, characterized in that: The fixed scraper (10) is fixedly mounted on the inner wall of the housing (1), and the spacing between the fixed scraper (10) and the disc cathode (5) is 0.2-0.8 mm.

9. An application method of a hydraulically driven rotating cathode electrochemical seawater chlorine production device, characterized in that A hydraulically driven rotating cathode electrochemical seawater chlorine production device as claimed in any one of claims 1 to 8, comprising: Seawater or seawater dilution enters the housing (1) from the water inlet (2), impacts the hydraulic impeller (7) to rotate, and drives the coaxially connected disc cathode (5) to rotate accordingly. After the external DC power supply is started, the current is transmitted to the surfaces of the disc cathode (5) and the fixed anode (6) through the rotating shaft conductive connecting rod (9) and the fixed conductive connecting rod (8), respectively, to trigger reduction and oxidation reactions. The fixed anode (6) activates the chloride ions and water molecules in the water to generate active oxidizing species, and the disc cathode (5) activates the water molecules to generate hydrogen. At the same time, a local alkaline environment is formed on the surface of the disc cathode (5), which reacts with the hardness ions in the seawater to generate precipitation, and gradually forms nuclei and precipitates near the surface of the disc cathode (5) to become scale. The relative movement between the disc cathode (5) and the fixed scraper (10) allows the scale layer on the surface of the disc cathode (5) to be continuously removed, and the detached scale is scraped off and deposited on the bottom of the housing (1) and discharged through the sewage outlet (4). The seawater after the electrolysis reaction is discharged through the water outlet (3) to the downstream storage tank for use.

10. The use according to claim 9, characterized in that The electrolysis current density of the device is 1000-3000 A / m 2 The device requires a chloride concentration of at least 3000 mg / L for electrolyzing seawater.

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