A treatment device for electroplating wastewater by evaporation separation

Abstract

This invention discloses a treatment device for evaporating and separating electroplating wastewater, which can improve the heat and mass transfer performance of high-concentration electroplating wastewater in the lower part of the evaporation separation tower. The treatment device includes a hot air assembly, an evaporation separation tower, an electroplating wastewater assembly, and an exhaust assembly. The evaporation separation tower includes a top, a tower body, and a base connected sequentially from top to bottom. The hot air assembly is connected to the top of the evaporation separation tower, the electroplating wastewater assembly is connected to the top of the evaporation separation tower, and the exhaust assembly is connected to the lower part of the tower body. From top to bottom, the tower body of the evaporation separation tower gradually decreases in size.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, and specifically relates to a treatment device for evaporating and separating electroplating wastewater. Background Technology

[0002] Electroplating wastewater is a type of wastewater generated during industrial production that contains harmful substances such as heavy metals and high levels of acidity and alkalinity, posing a significant threat to the environment and human health. Therefore, effective treatment technology for electroplating wastewater is crucial for reducing environmental pollution.

[0003] Evaporation separation technology is a common method for treating electroplating wastewater. This technology utilizes the principle of evaporation to remove water from the wastewater, concentrating and separating harmful substances, thereby achieving wastewater treatment and resource recycling. The concentration of electroplating wastewater generated in enterprises or factories is approximately below 15%. Currently, among traditional treatment methods, only evaporation separation technology can effectively achieve zero discharge of electroplating wastewater.

[0004] In current evaporation separation systems for electroplating wastewater treatment, the concentration of electroplating wastewater increases continuously from top to bottom within the evaporation separation tower. The high-concentration electroplating wastewater in the lower part of the tower often exhibits poor heat and mass transfer performance, requiring a higher-temperature separation medium, thus increasing the energy consumption of the evaporation separation process. How to improve the heat and mass transfer performance of the high-concentration electroplating wastewater in the lower part of the evaporation separation tower without increasing energy consumption has become a technical challenge for those skilled in the art. Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing technologies, this invention provides a treatment device for evaporation separation of electroplating wastewater, effectively solving the problem of increasingly high concentrations of electroplating wastewater in the later stages of evaporation treatment, making it difficult to handle.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A treatment device for evaporating and separating electroplating wastewater is characterized in that the treatment device includes a hot air assembly, an evaporation and separation tower, an electroplating wastewater assembly, and an exhaust assembly. The evaporation and separation tower includes a top, a tower body, and a base connected sequentially from top to bottom. The hot air assembly is connected to the top of the evaporation and separation tower, the electroplating wastewater assembly is connected to the top of the evaporation and separation tower, and the exhaust assembly is connected to the lower part of the tower body of the evaporation and separation tower. The tower body of the evaporation and separation tower gradually decreases in size from top to bottom.

[0008] As a preferred example, the hot air assembly includes a vortex fan and an electric heater, the vortex fan being connected to the top of the evaporation separation tower via a first pipe, and the electric heater being connected in the first pipe.

[0009] As a preferred example, the electroplating wastewater assembly includes a flow calibration column, a storage tank, a diaphragm pump, and a pressure nozzle. The outlet of the storage tank is connected to the first port of a three-way pipe via a first valve. The flow calibration column is connected to the second port of the three-way pipe via a second valve. The inlet of the diaphragm pump is connected to the third port of the three-way pipe. The outlet of the diaphragm pump is connected to the pressure nozzle via a second pipe. The second pipe passes through the top of the evaporation separation tower, and the pressure nozzle is located in the upper part of the inner cavity of the evaporation separation tower.

[0010] As a preferred example, the electroplating wastewater assembly further includes a safety valve, which is connected to a third pipe and a second pipe; the outlet end of the third pipe is located above the storage tank.

[0011] As a preferred example, the electroplating wastewater assembly further includes a pulse damper located outside the evaporation separation tower, the pulse damper being connected to the top of the branch, and the bottom of the branch being connected to the top of the second pipe.

[0012] As a preferred example, the exhaust assembly includes a fourth pipe and a bag filter located outside the evaporation separation tower. The fourth pipe passes through the evaporation separation tower, the inlet of the fourth pipe is located in the lower part of the inner cavity of the evaporation separation tower, the bag filter is connected in the fourth pipe, and the outlet of the fourth pipe is located outside the evaporation separation tower.

[0013] As a preferred example, the angle of the evaporation separation tower is 5 to 15°.

[0014] As a preferred example, the top of the evaporation separation tower includes a first expansion section, a middle section, a second expansion section, and a connecting section connected sequentially from top to bottom; the diameter of the first expansion section gradually increases from top to bottom, the diameter of the second expansion section gradually increases from top to bottom, the middle section and the connecting section are both cylindrical, the bottom diameter of the first expansion section, the top diameter of the second expansion section, and the diameter of the middle section are all equal, and the bottom diameter of the second expansion section and the diameter of the connecting section are equal.

[0015] As a preferred example, the height of the evaporation separation tower is calculated according to formula (1):

[0016]

[0017] Among them, v d The value represents the droplet velocity in m / s; H represents the height of the tower in m; and g represents the acceleration due to gravity in m / s². 2 ;ρ a This indicates the air density in the evaporation separation tower, with units of kg / m³. 3 ;ρ d This indicates the density of droplets ejected from the pressure nozzle, expressed in kg / m³. 3 ;r dThe radius of the droplets ejected from the pressure nozzle is expressed in meters (m); ψ represents the resistance coefficient of the droplets within the evaporation separation tower, which is dimensionless; v a This indicates the speed of air within the tower, measured in m / s.

[0018] As a preferred example, the temperature inside the evaporation separation tower is 100–150°C during operation.

[0019] Compared with existing technologies, the electroplating wastewater treatment device of the present invention effectively solves the problem of increasingly high concentrations of electroplating wastewater in the later stages of evaporation treatment, making it difficult to handle. High-concentration electroplating wastewater exhibits high thermal resistance to heat and mass transfer with hot air, resulting in poor heat and mass transfer efficiency. The present invention, by designing a tower with a gradually tapering shape from top to bottom, gradually reduces the pressure of the high-concentration electroplating wastewater located in the lower part of the evaporation separation tower, thereby increasing the driving force for heat and mass transfer and enhancing the heat and mass transfer effect between the high-concentration electroplating wastewater and hot air. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the evaporation separation tower in an embodiment of the present invention.

[0022] In the diagram: 1. Vortex fan; 2. Electric heater; 3. Evaporation separation tower; 31. Top; 311. First expansion section; 312. Middle section; 313. Second expansion section; 314. Connecting section; 32. Tower body; 33. Base; 4. Flow calibration column; 5. Liquid storage tank; 6. Diaphragm pump; 7. Safety valve; 8. Pulse damper; 9. Pressure nozzle; 10. Bag filter; 11. First valve; 12. Second valve. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0024] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a treatment device for evaporating and separating electroplating wastewater, comprising a hot air assembly, an evaporation separation tower 3, an electroplating wastewater assembly, and an exhaust assembly. The evaporation separation tower 3 includes a top 31, a tower body 32, and a base 33 connected sequentially from top to bottom. The hot air assembly is connected to the top 31 of the evaporation separation tower, the electroplating wastewater assembly is connected to the top 31 of the evaporation separation tower, and the exhaust assembly is connected to the lower part of the tower body 32 of the evaporation separation tower; the tower body 32 of the evaporation separation tower gradually decreases in size from top to bottom.

[0025] In the processing apparatus of the above embodiment, the hot air assembly is used to input hot air at a set temperature into the evaporation separation tower 3. The electroplating wastewater assembly is used to input electroplating wastewater into the evaporation separation tower 3. The electroplating wastewater and hot air fall from top to bottom in the evaporation separation tower 3, and heat exchange occurs during the fall, causing the water in the electroplating wastewater to evaporate. At the bottom of the evaporation separation tower 3, exhaust gas is discharged from the exhaust assembly, and the water in the electroplating wastewater evaporates, forming solid recovery. The electroplating wastewater flows from top to bottom in the tower body 32 of the evaporation separation tower, with its concentration increasing. Compared to the electroplating wastewater located in the upper part of the tower body 32, the electroplating wastewater located in the lower part of the tower body 32 is high-concentration electroplating wastewater. The high-concentration electroplating wastewater in the lower part of the evaporation separation tower 3 has a large thermal resistance to heat and mass transfer with the hot air, resulting in poor heat and mass transfer effect. In this embodiment, the tower body 32 of the evaporation separation tower gradually decreases in size, rather than being a cylindrical shape with a uniform diameter. The evaporation separation tower 3 gradually shrinks in size. After reducing the pressure of the high-concentration electroplating wastewater, the driving force for heat and mass transfer can be improved, thereby enhancing the heat and mass transfer between the high-concentration electroplating wastewater and the hot air.

[0026] By utilizing the principle of a converging nozzle, the pressure of the electroplating wastewater in the evaporation separation tower 3 is gradually reduced, effectively treating the electroplating wastewater with a higher concentration in the lower part of the tower body 32, thus achieving the evaporation and separation of the high-concentration electroplating wastewater in the lower part of the tower body 32. If the high-concentration electroplating wastewater is not treated in this way, it may be difficult for the electroplating wastewater in the lower part of the evaporation separation tower 3 to transfer heat and mass with the hot air, and the water content of the electroplating wastewater hydrate separated by the evaporation separation tower (3) may be too high.

[0027] The electroplating wastewater to be treated has a mass concentration of 20-40%, and the crystallization concentration varies depending on the solute composition. As the water in the electroplating wastewater is evaporated and separated, the concentration of the wastewater continuously increases until crystallization occurs.

[0028] Preferably, the hot air assembly includes a vortex blower 1 and an electric heater 2. The vortex blower 1 is connected to the top 31 of the evaporation separation tower via a first duct, and the electric heater 2 is connected to the first duct. The vortex blower 1 is used to draw in ambient air. The electric heater 2 is used to heat the ambient air to the required temperature. The ambient air is heated to the required temperature by the vortex blower 1 and the electric heater 2, forming hot air, which is then delivered to the inner cavity of the top 31 of the evaporation separation tower. The temperature of the hot air is 110–150°C. The ambient air is at room temperature, for example, 18–22°C.

[0029] Preferably, the electroplating wastewater assembly includes a flow calibration column 4, a storage tank 5, a diaphragm pump 6, and a pressure nozzle 9. The outlet of the storage tank 5 is connected to the first port of a three-way pipe through a first valve 11. The flow calibration column 4 is connected to the second port of the three-way pipe through a second valve 12. The inlet of the diaphragm pump 6 is connected to the third port of the three-way pipe. The outlet of the diaphragm pump 6 is connected to the pressure nozzle 9 through a second pipe. The second pipe passes through the top 31 of the evaporation separation tower, and the pressure nozzle 9 is located in the upper part of the inner cavity of the evaporation separation tower 3.

[0030] In the preferred embodiment described above, the flow calibration column 4 is used to measure the flow rate of the electroplating wastewater. The storage tank 5 is used to store the electroplating wastewater. The diaphragm pump 6 is used to pressurize the electroplating wastewater. The pressure nozzle 9 is used to atomize the electroplating wastewater into a spray. During operation, the first valve 11 and the second valve 12 are opened, and the electroplating wastewater in the storage tank 5 flows into the diaphragm pump 6. After being pressurized by the diaphragm pump 6, the electroplating wastewater flows to the pressure nozzle 9. The pressure nozzle 9 atomizes the electroplating wastewater into a spray within the inner cavity of the top 31 of the evaporation separation tower. During this process, the flow rate of the electroplating wastewater in the storage tank 5 is measured by the flow calibration column 4. Atomizing the electroplating wastewater into a spray through the pressure nozzle 9 facilitates heat exchange between the electroplating wastewater and the hot air supplied from the hot air assembly, making it easier for the water in the atomized electroplating wastewater to evaporate. The atomized electroplating wastewater and the hot air converge at the top 31 of the evaporation separation tower and flow downwards. During this flow, the atomized electroplating wastewater and the hot air further exchange heat.

[0031] The diaphragm pump 6 can regulate the flow rate and pressure of the electroplating wastewater. The electric heater 2 can regulate the air temperature. Depending on the composition of the electroplating wastewater or the operating conditions, the heat and mass transfer processes within the evaporation separation tower 3 are enhanced by adjusting the flow rate and pressure of the electroplating wastewater and the air temperature.

[0032] Preferably, the electroplating wastewater assembly also includes a safety valve 7, which is connected to a third pipe and a second pipe; the outlet of the third pipe is located above the storage tank 5. The safety valve 7 is used to prevent excessive pressure in the second pipe from causing the electroplating wastewater to burst. The safety valve has a pressure threshold. When the pressure of the electroplating wastewater in the second pipe exceeds the pressure threshold, the safety valve 7 opens, allowing some of the wastewater in the second pipe to flow from the third pipe into the storage tank 5, thus relieving pressure. When the pressure of the electroplating wastewater in the second pipe is lower than the pressure threshold, the safety valve 7 closes.

[0033] Preferably, the electroplating wastewater assembly also includes a pulse damper 8 located outside the evaporation separation tower 3. The pulse damper 8 is connected to the top of the branch, and the bottom of the branch is connected to the top of the second pipe. The pulse damper 8 is used to eliminate liquid pressure pulsations or flow pulsations in the second pipe and prevent the second pipe from vibrating. Excessive vibration can cause metal material loss.

[0034] Preferably, the exhaust assembly includes a fourth duct and a bag filter 10 located outside the evaporation separation tower 3. The fourth duct passes through the evaporation separation tower 3, with its inlet located in the lower part of the inner cavity of the tower 3. The bag filter 10 is connected to the fourth duct, and its outlet is located outside the tower 3. In the evaporation separation tower 3, hot air and electroplating wastewater exchange heat, causing the water in the wastewater to evaporate. The airflow exits the evaporation separation tower 3 through the fourth duct. During the airflow process, some solid waste may be carried along. Therefore, by installing the bag filter 10 in the fourth duct, the solid waste in the airflow is filtered and collected.

[0035] Preferably, the angle of the evaporation separation tower 32 is 5-15°. During operation, the temperature inside the evaporation separation tower 3 is 100-150℃.

[0036] In a preferred embodiment, the top 31 of the evaporation separation tower includes a first expansion section 311, a middle section 312, a second expansion section 313, and a connecting section 314 connected sequentially from top to bottom. The diameter of the first expansion section 311 gradually increases from top to bottom, the diameter of the second expansion section 313 gradually increases from top to bottom, the middle section 312 and the connecting section 314 are both cylindrical, and the bottom diameter of the first expansion section 311, the top diameter of the second expansion section 313, and the diameter of the middle section 312 are all equal. The bottom diameter of the second expansion section 313 and the diameter of the connecting section 314 are equal. More preferably, the first expansion section 311, the middle section 312, the second expansion section 313, and the connecting section 314 are integrally formed into a single piece. The diameter of the first expansion section 311 gradually increases from top to bottom. The diameter of the second expansion section 313 gradually increases from top to bottom. The middle section 312 and the connecting section 314 are cylindrical. The cylindrical middle section 312 is provided to allow the second pipe to pass through the evaporation separation tower 3, facilitating its installation. The cylindrical connecting section 314 is provided to connect the top 31 of the evaporation separation tower to the tower body 32. Figure 2 The top 31 of the evaporation separation tower can be connected to the tower body 32 via a connecting flange. Both the first expansion section 311 and the second expansion section 313 are funnel-shaped, wider at the bottom than the top, to reduce the airflow velocity, allowing the hot air to mix more thoroughly with the mist-like electroplating wastewater, thus accelerating the evaporation of water in the wastewater. The airflow passing through the vortex fan 1 and the electric heater 2 has a relatively high velocity after entering the top 31 of the evaporation separation tower. The first expansion section 311 and the second expansion section 313 reduce the airflow velocity.

[0037] Preferably, the height 32 of the evaporation separation tower is calculated according to formula (1):

[0038]

[0039] Among them, v dThe value represents the droplet velocity in m / s; H represents the height of the tower (32 m); g represents the acceleration due to gravity in m / s². 2 ;ρ a This indicates the air density in evaporation separation tower 3, in kg / m³. 3 ;ρ d This indicates the density of the liquid droplets ejected from pressure nozzle 9, in kg / m³. 3 ;r d The radius of the droplet ejected from pressure nozzle 9 is expressed in meters (m); ψ represents the resistance coefficient of the droplet within the evaporation separation tower 3, which is dimensionless; v a The velocity of air within tower 32 is expressed in m / s. ψ is calculated according to equation (2):

[0040]

[0041] Where Re is the Reynolds number of electroplating wastewater, and is a dimensionless coefficient.

[0042] The height of the evaporation separation tower 32 is calculated according to formula (1), so that after the electroplating wastewater enters the evaporation separation tower 3, it flows from top to bottom in the tower body 32 to achieve complete evaporation and separation of the electroplating wastewater in the tower body.

[0043] In this embodiment of the invention, the treatment device can be divided into two processes: an electroplating wastewater process and a hot air process. The hot air process is as follows: ambient air drawn in by the vortex blower 1 enters the electric heater 2. After the temperature rises to the required level, the hot air enters the evaporation separation tower 3. The hot air entering the evaporation separation tower 3 first passes through the first expansion section and the second expansion section to reduce its flow velocity, so as to exchange heat more evenly with the electroplating wastewater spray. It then flows through the tapered tower body 32, where the pressure is reduced. After completing the heat exchange, it is guided upwards through the fourth pipe at the bottom of the tower body 32. Through the physical structure, the waste gas and metal salt particles are initially separated, and the waste gas flows out of the evaporation separation tower 3. The electroplating wastewater process is as follows: the electroplating wastewater first passes through the flow calibration column 4 to determine its flow rate, then is pressurized by the diaphragm pump 6 and reaches the pressure nozzle 9. After atomization into a spray, it exchanges heat with the incoming hot air above, causing the water in the electroplating wastewater to gradually evaporate. After evaporation and separation, metal salt particles are formed and fall to the bottom of the tower.

[0044] The treatment apparatus described in the above embodiments or preferred examples can operate at medium and low temperatures (below 150°C), requires no special equipment, has low sealing requirements, consumes few consumables, has low material requirements, is simple and convenient, and has low operating costs. This treatment apparatus uses air as a separation carrier to treat electroplating wastewater; the separation carrier is readily available and is largely unrestricted by environmental factors.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A treatment device for evaporating and separating electroplating wastewater, characterized in that, The treatment device includes a hot air assembly, an evaporation separation tower (3), an electroplating wastewater assembly, and an exhaust assembly, wherein... The evaporation separation tower (3) includes a top (31), a tower body (32), and a base (33) connected from top to bottom; the hot air assembly is connected to the top (31) of the evaporation separation tower, the electroplating wastewater assembly is connected to the top (31) of the evaporation separation tower, and the exhaust assembly is connected to the lower part of the tower body (32) of the evaporation separation tower; from top to bottom, the tower body (32) of the evaporation separation tower gradually decreases in size; The top (31) of the evaporation separation tower includes a first expansion section (311), a middle section (312), a second expansion section (313), and a connecting section (314) connected from top to bottom. The diameter of the first expansion section (311) gradually increases from top to bottom, the diameter of the second expansion section (313) gradually increases from top to bottom, the middle section (312) and the connecting section (314) are both cylindrical, the bottom diameter of the first expansion section (311), the top diameter of the second expansion section (313) and the diameter of the middle section (312) are all equal, and the bottom diameter of the second expansion section (313) and the diameter of the connecting section (314) are equal.

2. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 1, characterized in that, The hot air assembly includes a vortex fan (1) and an electric heater (2), the vortex fan (1) being connected to the top (31) of the evaporation separation tower via a first pipe, and the electric heater (2) being connected in the first pipe.

3. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 1, characterized in that, The electroplating wastewater assembly includes a flow calibration column (4), a storage tank (5), a diaphragm pump (6), and a pressure nozzle (9). The outlet of the storage tank (5) is connected to the first port of the three-way pipe through a first valve (11). The flow calibration column (4) is connected to the second port of the three-way pipe through a second valve (12). The inlet of the diaphragm pump (6) is connected to the third port of the three-way pipe. The outlet of the diaphragm pump (6) is connected to the pressure nozzle (9) through a second pipe. The second pipe passes through the top (31) of the evaporation separation tower. The pressure nozzle (9) is located in the upper part of the inner cavity of the evaporation separation tower (3).

4. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 3, characterized in that, The electroplating wastewater assembly also includes a safety valve (7), which is connected to a third pipe and a second pipe; the outlet end of the third pipe is located above the storage tank (5).

5. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 3, characterized in that, The electroplating wastewater assembly also includes a pulse damper (8) located outside the evaporation separation tower (3), the pulse damper (8) being connected to the top of the branch, and the bottom of the branch being connected to the top of the second pipe.

6. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 1, characterized in that, The exhaust assembly includes a fourth pipe and a bag filter (10) located outside the evaporation separation tower (3). The fourth pipe passes through the evaporation separation tower (3), the inlet of the fourth pipe is located in the lower part of the inner cavity of the evaporation separation tower (3), the bag filter (10) is connected in the fourth pipe, and the outlet of the fourth pipe is located outside the evaporation separation tower (3).

7. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 1, characterized in that, The angle of the tower body (32) of the evaporation separation tower is 5 to 15°.

8. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 1, characterized in that, The height of the evaporation separation tower (32) is calculated according to formula (1): Equation (1) in, The value represents the droplet velocity in m / s; H represents the height of the tower (32) in m; g represents the gravitational acceleration in m / s². 2 ; This indicates the air density in the evaporation separator (3), expressed in kg / m³. 3 ; This indicates the density of the liquid droplets ejected by the pressure nozzle (9), in kg / m³. 3 ; The radius of the droplet ejected by the pressure nozzle (9) is expressed in meters. The resistance coefficient of the droplets in the evaporation separation tower (3) is dimensionless; The velocity of air in the tower body (32) is expressed in m / s.

9. The treatment apparatus for evaporation separation of electroplating wastewater according to claim 1, characterized in that, During operation, the temperature inside the evaporation separation tower (3) is 100-150℃.

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