Multifunctional electrochemical wastewater treatment device

Abstract

The utility model provides a kind of multifunctional electrochemical wastewater treatment device, under the action of additional electric field, synchronous utilization anode reaction of electrode group generates flocculating agent in situ to remove impurity quickly, using cathode reaction produces strong alkaline environment and precipitates water into scale ion, while through sustained ultrasonic cleaning and regular compressed air purging automatic descaling, the scale precipitate falls off under the action of gravity and enters the settlement zone and settles and separates, the utility model can remove high concentration suspended solids, petroleum and calcium-magnesium ions in water quickly and efficiently in one electrochemical reactor, reduce total hardness, and ensure that reactor can keep efficient and continuous operation through combined descaling means.

Description

Technical Field

[0001] This utility model belongs to the technical field of electrochemical softening treatment, specifically relating to a multifunctional electrochemical wastewater treatment device. Background Technology

[0002] Domestically and internationally, wastewater treatment primarily relies on the addition of chemical agents such as scale inhibitors and disinfectants. While effective, this method is costly, and scale inhibitors contain high levels of phosphorus, which can easily lead to eutrophication of natural water bodies and environmental pollution. In recent years, electrochemical methods have become increasingly prevalent in wastewater treatment. This method utilizes direct current to induce electrolysis of water on the cathode surface. The resulting large amount of OH- reacts with hardness and alkalinity ions in the water to form CaCO3 and Mg(OH)2 precipitates, which are deposited on the cathode surface, effectively removing hardness and alkalinity ions. Simultaneously, H+ generated from the oxygen evolution reaction at the DSA electrode further reduces alkalinity, and hypochlorite disinfectant produced by the chlorine evolution side reaction sterilizes and kills algae in the circulating cooling water. Compared to chemical agent addition methods, electrochemical methods offer advantages such as high treatment efficiency, environmental friendliness, low operating costs, wide applicability, and ease of operation.

[0003] While electrochemical softening has many advantages, it still has some drawbacks in cathode descaling. Currently, commonly used descaling methods both domestically and internationally include mechanical descaling, acid washing descaling, electrode reversal descaling, and alternating current descaling. Mechanical descaling is simple to operate and widely used, but the installation of mechanical scrapers between the anode and cathode inevitably increases the distance between the electrodes, increasing energy consumption and affecting hardness removal efficiency due to the limited total area of ​​the cathode plate. Furthermore, the efficiency of mechanical descaling decreases significantly after long-term use. Acid washing descaling, while highly efficient, requires chemical reagents and generates acidic wastewater. Electrode reversal descaling also has high efficiency, but frequent reversals significantly shorten electrode life. Alternating current descaling requires periodic, rapid increases in operating current; while it offers high descaling efficiency, it also exacerbates electrode wear and significantly shortens electrode life, with a more severe impact on the lifespan of soluble anodes. Therefore, improvements should be made to current electrochemical wastewater treatment devices to achieve automated and efficient descaling while maintaining high-efficiency descaling, and to improve the utilization rate of the anode reaction, thereby increasing its application potential in industrial wastewater with high salt, high hardness, and high suspended solids. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a multifunctional electrochemical wastewater treatment device that combines coagulation and impurity removal, softening and descaling, and automatic descaling. It can significantly improve electrolysis efficiency, reduce treatment costs, ensure long-term stable operation of the system, and eliminate safety hazards.

[0005] The embodiments of this application are implemented as follows:

[0006] This application provides a multifunctional electrochemical wastewater treatment device, characterized in that it includes an electrochemical reactor, with an inlet and an outlet respectively provided on the upper sides of both sides of the electrochemical reactor, and multiple baffles spaced apart on the upper part, with electrode groups provided in the gaps, the electrode groups being electrically connected to an external power source, and multiple inclined plates evenly spaced in the middle of the electrochemical reactor, with a conical hopper corresponding to the bottom of the inclined plates, the bottom of the conical hopper being connected to a sludge discharge port.

[0007] In some optional implementations, the electrode assembly consists of multiple anode plates and multiple cathode plates arranged alternately and at equal intervals in parallel, and connected and fixed by fasteners. The top of each of the multiple anode plates is connected to an anode connecting plate, and the top of each of the multiple cathode plates is connected to a cathode connecting plate. The anode interface of the power supply is connected to the anode connecting plate interface through a terminal block, and the cathode interface is connected to the cathode connecting plate interface through a terminal block. All connections are fixed with metal nuts.

[0008] In some alternative implementations, the electrode assembly is surrounded by an ultrasonic transducer plate, which is connected to an ultrasonic generator outside the electrochemical reactor; each electrode plate of the electrode assembly is provided with a flushing gas pipe, which is evenly distributed with gas holes, and each flushing gas pipe is connected to an air compressor outside the electrochemical reactor through a main air inlet pipe, which is equipped with a solenoid valve.

[0009] In some alternative embodiments, the anode plate is a soluble metal electrode, the cathode plate is a mirror-finished metal or alloy electrode, the terminal block is a titanium-plated copper busbar, and the metal nut is a titanium nut or a titanium-plated copper nut.

[0010] In some alternative embodiments, the fastener includes a fixing rod that passes through the electrode assembly, with each end of the fixing rod secured by a washer nut.

[0011] In some alternative embodiments, the vents are arranged on the side of the flushing duct facing the cathode plate.

[0012] In some alternative embodiments, the fastener is made of one of polytetrafluoroethylene, perfluoroethylene, nylon, or epoxy resin.

[0013] In some alternative embodiments, the number of anode plates is one less than the number of cathode plates; the total area ratio of cathode plates to anode plates is 1.5-2.0:1.0, and the distance between cathode plates and anode plates is 4.0-5.0 cm.

[0014] In some alternative embodiments, the ultrasonic transducer is made of titanium; the flushing air tube is an aluminum-plastic tube, the distance between it and the cathode plate is 1.5-2.0 cm, the outer diameter of the flushing air tube is 13-15 mm, the pore diameter is 2-4 mm, and the blowing angle of the pore is 30-60°.

[0015] In some optional implementations, the ultrasonic generator, air compressor, air intake pipe and solenoid valve are each in two sets, respectively located on both sides of the electrochemical reactor; the electrode group consists of four sets divided into left and right groups; and the power supply consists of two sets, respectively electrically connected to the left and right electrode groups.

[0016] The beneficial effects of this application are: the multifunctional electrochemical wastewater treatment device provided by this application combines coagulation and impurity removal, softening and descaling, and automatic descaling, which can significantly improve electrolysis efficiency, reduce treatment costs, ensure long-term stable operation of the system and eliminate safety hazards; in addition to being suitable for softening and impurity removal of produced water and fracturing flowback fluid from oil and gas fields. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the multifunctional electrochemical wastewater treatment device in the embodiments of this application;

[0019] Figure 2 This is a schematic diagram of the electrode assembly installation in an embodiment of this application;

[0020] Figure 3 This is a top view of the electrode assembly in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of the flushing air pipe in an embodiment of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be understood that the sequence number of each step in the embodiment does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0025] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0026] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0027] like Figure 1 As shown, the present application provides a multifunctional electrochemical wastewater treatment device, including an electrochemical reactor 1. The upper parts of both sides of the electrochemical reactor are respectively provided with an inlet 2 and an outlet 3. Multiple baffles 4 are spaced apart on the upper part, and an electrode group is provided in the gap. The electrode group is electrically connected to an external power supply 5. Multiple inclined plates 6 are evenly spaced in the middle of the electrochemical reactor. A conical hopper 7 is provided corresponding to the bottom of the inclined plate, and the bottom of the conical hopper is connected to a sludge discharge port.

[0028] like Figure 2 , Figure 3 As shown, the electrode assembly consists of multiple anode plates 8 and multiple cathode plates 9 arranged alternately and at equal intervals in parallel, and connected and fixed by fasteners. The tops of the multiple anode plates are all connected to the anode connecting plate 10, and the tops of the multiple cathode plates are all connected to the cathode connecting plate 11. The anode interface of the power supply is connected to the anode connecting plate interface through the terminal block 12, and the cathode interface is connected to the cathode connecting plate interface through the terminal block. All connections are fixed with metal nuts. The fasteners include a fixing rod 13 that passes through the electrode assembly, and the two ends of the fixing rod are respectively fastened with washers and nuts.

[0029] The principle of coagulation, impurity removal, softening, and descaling in an electrochemical reactor is as follows:

[0030] Under the influence of an applied electric field, the metal ions produced by the oxidation reaction at the anode are further hydrolyzed to form colloidal hydroxides. These hydroxides remove high concentrations of suspended solids, petroleum hydrocarbons, and some COD from the water through charge neutralization and adsorption bridging. Simultaneously, a hydrogen evolution reaction occurs at the cathode, producing H2 and creating a locally strongly alkaline environment around it, which reacts with calcium in the water. 2+ Mg 2+ and HCO3 -The reaction produces CaCO3 and Mg(OH)2 precipitates, which are gradually deposited on the cathode surface in the form of precipitates, thus completing the softening and descaling process.

[0031] Example 1

[0032] The electrode assembly is surrounded by an ultrasonic transducer 14, which is connected to an ultrasonic generator 15 outside the electrochemical reactor; each electrode plate in the electrode assembly is equipped with a flushing gas pipe 16 (see...). Figure 4 The flushing pipes have evenly distributed air holes 17 on the side facing the cathode plate. The flushing pipes are all connected to the air compressor 18 outside the electrochemical reactor through the main air inlet pipe. The main air inlet pipe is equipped with a solenoid valve 19.

[0033] Furthermore, the anode plate is a soluble metal electrode, such as an iron plate or an aluminum plate; the cathode plate is a mirror-finish corrosion-resistant metal or alloy electrode, such as mirror-finish stainless steel, mirror-finish titanium alloy, or mirror-finish nickel alloy; the terminal block is a titanium-plated copper busbar; the metal nut is a corrosion-resistant titanium nut or a titanium-plated copper nut; and the fastener is one of polytetrafluoroethylene, polytetrafluoroethylene propylene, nylon, or epoxy resin.

[0034] During the operation of the electrochemical reactor, the smooth surface of the mirror-finished corrosion-resistant cathode plate can effectively reduce the adhesion between the scale deposit and the cathode, allowing most of the generated scale deposit to fall off directly, thus preventing the formation of a large amount of scale on the cathode surface from the source.

[0035] Furthermore, the number of anode plates is one less than that of cathode plates; the total area ratio of cathode plates to anode plates is 1.5-2.0:1.0, and the distance between cathode plates and anode plates is 4.0-5.0 cm. Having a larger cathode plate area than anode plates ensures more surface area for scale deposition.

[0036] Furthermore, the ultrasonic transducer is made of titanium; the purging tube is made of aluminum-plastic composite material, with a distance of 1.5-2.0 cm from the cathode plate, an outer diameter of 13-15 mm, an air hole diameter of 2-4 mm, and a purging angle of 30-60°.

[0037] By combining continuous ultrasonic output, the cavitation and shearing effects of ultrasound prevent the scale continuously generated by the reaction from stably adhering to the cathode surface. Finally, periodic descaling using compressed air flushing utilizes the high-speed airflow and bubble collapse to generate shearing force, directly impacting the scale layer on the cathode surface and breaking down the stable scale layer that has gradually accumulated over long-term operation. The combination of multiple descaling methods ensures that the electrochemical reactor maintains efficient and continuous operation.

[0038] Example 2

[0039] In this embodiment, there are two sets of ultrasonic generator, air compressor, air intake pipe and solenoid valve, which are respectively set on both sides of the electrochemical reactor; there are four sets of electrode groups divided into left and right groups; and there are two sets of power supplies, which are electrically connected to the left and right sets of electrode groups respectively.

[0040] The method using the above-mentioned multifunctional electrochemical wastewater treatment device includes the following steps:

[0041] 1. Wastewater enters the electrochemical reactor through the inlet until the electrode group is submerged. Two power supplies are turned on. The anode reaction generates flocculant in situ to quickly remove impurities, while the cathode reaction produces a strongly alkaline environment to precipitate scale-forming ions in the water. The wastewater passes through multiple electrode groups in sequence under the guidance of multiple baffles to improve the impurity and scale removal effect. At the same time, two ultrasonic generators are turned on to inhibit scale formation on the cathode plate surface and enhance mass transfer efficiency, thereby improving the impurity and scale removal effect.

[0042] 2. After the electrochemical reactor has been running for a period of time, turn on the two air compressors and control the opening time and flow rate of compressed air through the solenoid valves to periodically purge the surface of the cathode plate, breaking down the scale layer that has formed on the electrode surface and causing it to peel off; after purging, close the solenoid valves and wait for the next cycle to start them again.

[0043] 3. The scale deposits that detach in the electrochemical reactor settle under gravity, and the settling rate is accelerated with the assistance of inclined plates. After entering the cone hopper, they are periodically discharged through the sludge discharge port.

[0044] During the electrochemical reaction, the working cathode current density of a power source is 20-30 A / m. 2 The other power supply operates with a cathode current density of 10⁻¹⁵ A / m. 2 Both ultrasonic generators operate at a frequency of 40 kHz ± 5%, with one generator having a power density of 1.5-2.5 kW / m². 3 The other ultrasonic generator has a power density of 0.5-1.0 kW / m². 3 .

[0045] Both air compressors operate at compressed air pressures of 0.3-0.5 MPa; one of the air compressors controls a compressed air flushing cycle of 20-40 minutes, a flushing time of 2-4 minutes, and a gas volume of 6-9 m³ per flush. 3 / m 2 Cathode plate; another set of compressed air compressors controls the scouring cycle to 60-80 min, with a scouring time of 1-2 min and a gas volume of 2-4 m³ per scouring cycle. 3 / m 2 Cathode plate.

[0046] When wastewater passes through the first two sets of electrode groups under the action of baffles, suspended solids, petroleum and total hardness in the water are significantly removed; when it passes through the last two sets of electrode groups, the concentration of pollutants in the water is significantly reduced, and the cathode current density for electrochemical reaction, as well as the ultrasonic power density, gas flushing cycle and flushing time during automatic descaling, can all be significantly reduced or shortened.

[0047] In this embodiment, the power supply is a DC regulated power supply. Two sets of power supply, ultrasonic generator and air compressor are set up. The cathode current density, power density and rinsing time of the latter two sets of electrode groups are significantly lower than those of the former two sets of electrode groups. The rinsing cycle is significantly longer than that of the former two sets of electrode groups. This ensures the operating effect while greatly saving operating costs.

[0048] Example 3

[0049] Taking shale gas wastewater from a certain block in Fuling as the treatment target, a multifunctional electrochemical wastewater treatment device and method were used to treat it. The influent water quality was as follows: pH value 7.42, suspended solids 485 mg / L, petroleum hydrocarbons 63.4 mg / L, total hardness 1650 mg / L, ammonia nitrogen 62 mg / L, and COD 2880 mg / L.

[0050] In the following embodiment, the anode plate of the multifunctional electrochemical wastewater treatment device is an aluminum plate, the cathode plate is a mirror-finished titanium alloy, the area ratio of the cathode plate to the anode plate is 1.8:1.0, and the plate spacing is 5.0 cm. The distance between the flushing air pipe and the cathode plate is 2.0 cm, the outer diameter of the flushing air pipe is 15 mm, the pore diameter is 3 mm, and the purging angle of the pore is 45°.

[0051] During the electrochemical reaction, the cathode current density of the first power source is 30 A / m. 2 The other power supply operates with a cathode current density of 12 A / m. 2 Both ultrasonic generators operate at a frequency of 40 kHz, with one generator having a power density of 2.0 kW / m². 3 The other ultrasonic generator has a power density of 0.75 kW / m². 3 Both air compressors operate at a compressed air pressure of 0.4 MPa. One air compressor controls a compressed air flushing cycle of 30 minutes, with a flushing time of 4 minutes and a gas volume of 8 m³ per flush. 3 / m 2 Cathode plate; another set of compressed air compressors controls the rinsing cycle to 80 min, with a rinsing time of 1 min and a gas volume of 3 m³ per cycle. 3 / m 2 Cathode plate.

[0052] Under the above conditions, the suspended solids, petroleum hydrocarbons, total hardness, ammonia nitrogen, and COD in the effluent from the device were 65 mg / L, 16.3 mg / L, 72 mg / L, 52.5 mg / L, and 1420 mg / L, respectively.

[0053] Comparative Example 1:

[0054] Under the operating parameters of the above embodiments, the main pollutants in the effluent from the device are shown in Table 1 below, when only the ultrasonic generator, only the air compressor, and both are turned off. After both descaling methods are turned off, the voltage of the programmable DC regulated power supply tank rises sharply (4.4 V) after the device has been running continuously for 23 hours. To avoid the possibility of electrode breakdown due to excessive voltage and short circuits, the device needs to be shut down for descaling treatment. At this time, a large amount of deposits are attached to the electrode surface.

[0055] Table 1. Main pollutants in effluent after shutting down some equipment.

[0056] .

Claims

1. A multifunctional electrochemical wastewater treatment device, characterized in that, The device includes an electrochemical reactor, with an inlet and an outlet on the upper sides of both sides. Multiple baffles are spaced apart on the upper part, and electrode groups are installed in the gaps. The electrode groups are electrically connected to an external power source. Multiple inclined plates are evenly spaced in the middle of the electrochemical reactor, and a conical hopper is provided at the bottom of the inclined plates. The bottom of the conical hopper is connected to a sludge discharge port.

2. The multifunctional electrochemical wastewater treatment device according to claim 1, characterized in that, The electrode assembly consists of multiple anode plates and multiple cathode plates arranged alternately and at equal intervals in parallel, and connected and fixed by fasteners. The top of each anode plate is connected to an anode connecting plate, and the top of each cathode plate is connected to a cathode connecting plate. The anode interface of the power supply is connected to the anode connecting plate interface through a terminal block, and the cathode interface is connected to the cathode connecting plate interface through a terminal block. All connections are fixed with metal nuts.

3. The multifunctional electrochemical wastewater treatment device according to claim 2, characterized in that, The electrode assembly is surrounded by an ultrasonic transducer plate, which is connected to an ultrasonic generator outside the electrochemical reactor. Each electrode plate of the electrode assembly is provided with a flushing gas pipe, which is evenly distributed with gas holes. The flushing gas pipe is connected to an air compressor outside the electrochemical reactor through a main air inlet pipe, and a solenoid valve is provided on the main air inlet pipe.

4. The multifunctional electrochemical wastewater treatment device according to claim 3, characterized in that, The anode plate is a soluble metal electrode, the cathode plate is a mirror-finished metal or alloy electrode, the terminal block is a titanium-plated copper busbar, and the metal nut is a titanium nut or a titanium-plated copper nut.

5. A multifunctional electrochemical wastewater treatment device according to claim 2 or 4, characterized in that, The fixing component includes a fixing rod that passes through the electrode assembly, and the two ends of the fixing rod are respectively fastened by washers and nuts.

6. A multifunctional electrochemical wastewater treatment device according to claim 3 or 4, characterized in that, The air holes are arranged on the side of the flushing air pipe facing the cathode plate.

7. The multifunctional electrochemical wastewater treatment device according to claim 5, characterized in that, The fastener is made of one of polytetrafluoroethylene, perfluoroethylene, nylon, or epoxy resin.

8. A multifunctional electrochemical wastewater treatment device according to claim 4, characterized in that, The number of anode plates is one less than the number of cathode plates; the total area ratio of cathode plates to anode plates is 1.5-2.0:1.0, and the distance between cathode plates and anode plates is 4.0-5.0 cm.

9. A multifunctional electrochemical wastewater treatment device according to claim 4, characterized in that, The ultrasonic transducer plate is made of titanium; the flushing air pipe is an aluminum-plastic pipe, the distance between it and the cathode plate is 1.5-2.0 cm, the outer diameter of the flushing air pipe is 13-15 mm, the diameter of the air hole is 2-4 mm, and the blowing angle of the air hole is 30-60°.

10. A multifunctional electrochemical wastewater treatment device according to claim 4, characterized in that, The ultrasonic generator, air compressor, air intake pipe and solenoid valve are each in two sets, respectively set on both sides of the electrochemical reactor; the electrode group consists of four sets divided into left and right groups; the power supply consists of two sets, which are electrically connected to the left and right electrode groups respectively.

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