Treatment device for evaporating and separating electroplating wastewater

Abstract

The 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 at the middle lower part of an evaporation and separation tower. The treatment device comprises a hot air assembly, an evaporation separation tower, an electroplating wastewater assembly and an exhaust assembly, wherein the evaporation separation tower comprises a top, a tower body and a base which are sequentially connected from top to bottom; the hot air assembly is connected with the top of the evaporation separation tower, the electroplating wastewater assembly is connected with the top of the evaporation separation tower, and the exhaust assembly is connected with the lower part of a tower body of the evaporation separation tower; and the tower body of the evaporation separation tower is gradually reduced from top to bottom.

Description

Technical Field

[0001] The invention belongs to the field of sewage treatment, and in particular relates to a treatment device for evaporating and separating electroplating wastewater. Background Art

[0002] Electroplating wastewater is a kind of wastewater produced in industrial production that contains heavy metals, high pH and other harmful substances, which is very harmful to the environment and human health. In order to effectively treat electroplating wastewater and reduce pollution to the environment, electroplating wastewater treatment technology is particularly important.

[0003] Evaporation separation technology is a common method for treating electroplating wastewater. This technology uses the principle of evaporation to evaporate water from wastewater, concentrate and separate harmful substances in wastewater, thereby achieving wastewater treatment and resource recycling. The concentration of electroplating wastewater generated in the production of enterprises or factories is about 15%. At present, among the traditional treatment methods, only evaporation separation technology can effectively achieve zero discharge of electroplating wastewater and waste liquid.

[0004] In the current evaporation separation electroplating wastewater treatment system, the concentration of electroplating wastewater increases continuously from top to bottom in the evaporation separation tower. The high-concentration electroplating wastewater in the lower part of the evaporation separation tower often has poor heat and mass transfer performance. At this time, a higher temperature separation medium is required, thereby increasing the energy consumption of evaporation separation treatment. How to improve the heat and mass transfer performance of high-concentration electroplating wastewater in the lower part of the evaporation separation tower without increasing energy consumption has become a technical problem faced by those skilled in the art. Summary of the invention

[0005] In order to solve the shortcomings and deficiencies of the prior art, the present invention provides a treatment device for evaporating and separating electroplating wastewater, which effectively solves the problem that the concentration of electroplating wastewater becomes increasingly high and difficult to treat in the later stage of electroplating wastewater evaporation treatment.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A treatment device for evaporating and separating electroplating wastewater, characterized in that the treatment device comprises a hot air component, an evaporation separation tower, an electroplating wastewater component, and an exhaust component; the evaporation separation tower comprises a top, a tower body, and a base which are sequentially connected from top to bottom; the hot air component is connected to the top of the evaporation separation tower, the electroplating wastewater component is connected to the top of the evaporation separation tower, and the exhaust component is connected to the lower part of the tower body of the evaporation separation tower; from top to bottom, the tower body of the evaporation separation tower gradually shrinks.

[0008] As a preferred example, the hot air component includes a vortex fan and an electric heater. The vortex fan is connected to the top of the evaporative separation tower through a first pipeline, and the electric heater is connected in the first pipeline.

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

[0010] As a preferred example, the electroplating wastewater component also includes a safety valve, which is connected to the second pipeline through a third pipeline; the liquid outlet end of the third pipeline is located above the liquid storage tank.

[0011] As a preferred example, the electroplating wastewater component also includes a pulse damper located outside the evaporation separation tower, the pulse damper is connected to the top end of the branch, and the bottom end of the branch is connected to the top end of the second pipeline.

[0012] As a preferred example, the exhaust assembly includes a fourth pipe and a bag dust collector located outside the evaporative separation tower, the fourth pipe passes through the evaporative separation tower, the air inlet of the fourth pipe is located at the lower part of the inner cavity of the evaporative separation tower, the bag dust collector is connected to the fourth pipe, and the air outlet of the fourth pipe is located outside the evaporative separation tower.

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

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

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

[0016]

[0017] Among them, v d represents the droplet velocity in m / s; H represents the tower height in m; g represents the gravitational acceleration in m / s 2 ρ a Indicates the air density in the evaporation separation tower, in kg / m 3 ρ d Indicates the density of droplets sprayed from a pressure nozzle in kg / m 3 ; r drepresents the radius of the droplets sprayed from the pressure nozzle, in meters; ψ represents the resistance coefficient of the droplets in the evaporation separation tower, dimensionless; v a Indicates the speed of air in the tower, in m / s.

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

[0019] Compared with the prior art, the device for treating electroplating wastewater by evaporation and separation of the present invention effectively solves the problem that the concentration of electroplating wastewater becomes increasingly high and difficult to treat in the later stage of electroplating wastewater evaporation treatment. The heat and mass transfer resistance between high-concentration electroplating wastewater and hot air is large, resulting in poor heat and mass transfer effect. The present invention gradually reduces the pressure of high-concentration electroplating wastewater located in the middle and lower part of the evaporation and separation tower by setting a tower body that tapers from top to bottom, thereby improving the driving force of heat and mass transfer, and enhancing the effect of heat and mass transfer between high-concentration electroplating wastewater and hot air. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0022] In the figure: vortex fan 1, electric heater 2, evaporation separation tower 3, top 31, first expansion part 311, middle part 312, second expansion part 313, connecting part 314, tower body 32, base 33, flow calibration column 4, liquid storage tank 5, diaphragm pump 6, safety valve 7, pulse damper 8, pressure nozzle 9, bag filter 10, first valve 11, second valve 12. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] like Figure 1 and Figure 2 As shown, a treatment device for evaporation separation of electroplating wastewater according to an embodiment of the present invention comprises a hot air component, an evaporation separation tower 3, an electroplating wastewater component and an exhaust component. The evaporation separation tower 3 comprises a top 31, a tower body 32 and a base 33 which are connected in sequence from top to bottom. The hot air component is connected to the top 31 of the evaporation separation tower, the electroplating wastewater component is connected to the top 31 of the evaporation separation tower, and the exhaust component 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 shrinks.

[0025] In the treatment device of the above embodiment, the hot air component is used to input hot air of a set temperature into the evaporation separation tower 3. The electroplating wastewater component 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 is achieved during the falling process, and the water in the electroplating wastewater evaporates. At the bottom of the evaporation separation tower 3, the exhaust gas is discharged from the exhaust component, and the water in the electroplating wastewater evaporates to form solid recovery. The electroplating wastewater flows from top to bottom in the tower body 32 of the evaporation separation tower, and the concentration becomes higher and higher. Compared with the electroplating wastewater located at the upper part of the tower body 32, the electroplating wastewater located in the middle and lower part of the tower body 32 is high-concentration electroplating wastewater. The high-concentration electroplating wastewater in the middle and lower part of the evaporation separation tower 3 has a large thermal resistance to heat and mass transfer with hot air, resulting in poor heat and mass transfer effects. In this embodiment, the tower body 32 of the evaporation separation tower gradually shrinks, rather than being cylindrical with equal diameters. The tower body of the evaporation separation tower 3 is gradually reduced, and the driving force of heat and mass transfer can be increased after reducing the pressure of high-concentration electroplating wastewater, thereby enhancing the effect of heat and mass transfer between high-concentration electroplating wastewater and hot air.

[0026] By using the principle of the converging nozzle, the pressure of the electroplating wastewater in the evaporation separation tower 3 is gradually reduced, and the electroplating wastewater with higher concentration in the middle and lower part of the tower body 32 is effectively treated, that is, the high-concentration electroplating wastewater in the middle and lower part of the tower body 32 is evaporated and separated. If the high-concentration electroplating wastewater is not treated in this way, it may cause the electroplating wastewater in the middle and lower part of the evaporation separation tower 3 to be difficult 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) is too high.

[0027] The mass concentration of the electroplating wastewater to be treated is 20-40%, and the crystallization concentration of electroplating wastewater solutions with different solute components is different. As the water in the electroplating wastewater solution is evaporated and separated, the concentration of the electroplating wastewater has been increasing until crystallization.

[0028] Preferably, the hot air assembly includes a vortex fan 1 and an electric heater 2, the vortex fan 1 is connected to the top 31 of the evaporative separation tower through a first pipeline, and the electric heater 2 is connected in the first pipeline. The vortex fan 1 is used to extract external ambient air. The electric heater 2 is used to heat the external ambient air to a desired temperature. The external ambient air is heated to a desired temperature by the vortex fan 1 and the electric heater 2 to form hot air, which is then transported to the inner cavity of the top 31 of the evaporative separation tower. The temperature of the hot air is 110 to 150°C. The external ambient air is normal temperature air, for example, air at 18 to 22°C.

[0029] Preferably, the electroplating wastewater component includes a flow calibration column 4, a liquid storage tank 5, a diaphragm pump 6 and a pressure nozzle 9, the outlet of the liquid 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, and the pressure nozzle 9 is located at the upper part of the inner cavity of the evaporation separation tower 3.

[0030] In the above preferred example, the flow calibration column 4 is used to measure the flow rate of electroplating wastewater. The liquid storage tank 5 is used to store 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 liquid 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 electroplating wastewater is atomized into a spray in the inner cavity of the top 31 of the evaporation separation tower through the pressure nozzle 9. In this process, the flow rate of the electroplating wastewater in the liquid storage tank 5 is measured by the flow calibration column 4. Atomizing the electroplating wastewater into a spray through the pressure nozzle 9 is more conducive to the heat exchange between the electroplating wastewater and the hot air transported from the hot air component, so that the water in the mist electroplating wastewater is easier to evaporate. The mist electroplating wastewater and the hot air converge at the top 31 of the evaporation separation tower and flow from top to bottom. During the flow process, the mist electroplating wastewater and the hot air further exchange heat.

[0031] The diaphragm pump 6 can adjust the flow rate and pressure of the electroplating wastewater. The electric heater 2 can adjust the air temperature. According to different electroplating wastewater components or working conditions, the heat and mass transfer process in the evaporation separation tower 3 is enhanced by adjusting the flow rate and pressure of the electroplating wastewater and the air temperature.

[0032] Preferably, the electroplating wastewater component further includes a safety valve 7, which is connected to the second pipeline through a third pipeline; the liquid outlet end of the third pipeline is located above the liquid storage tank 5. The safety valve 7 is used to prevent the second pipeline through which the electroplating wastewater flows from being over-pressured and causing the pipe to burst. A pressure threshold is provided in the safety valve. When the pressure of the electroplating wastewater in the second pipeline exceeds the pressure threshold, the safety valve 7 is opened, so that part of the electroplating wastewater in the second pipeline flows from the third pipeline to the liquid storage tank 5, thereby realizing the pressure relief function. When the pressure of the electroplating wastewater in the second pipeline is lower than the pressure threshold, the safety valve 7 is closed.

[0033] Preferably, the electroplating wastewater component further 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 pipeline. The pulse damper 8 is used to eliminate the pressure pulsation or flow pulsation of the liquid in the second pipeline and prevent the second pipeline from vibrating. Excessive vibration may cause metal material loss.

[0034] Preferably, 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 air inlet of the fourth pipe is located at the lower part of the inner cavity of the evaporation separation tower 3, the bag filter 10 is connected to the fourth pipe, and the air outlet of the fourth pipe is located outside the evaporation separation tower 3. In the evaporation separation tower 3, hot air and electroplating wastewater exchange heat, and the water in the electroplating wastewater evaporates. The airflow is discharged from the evaporation separation tower 3 from the fourth pipe. During the flow of the airflow, some solid waste may be carried. Therefore, by arranging the bag filter 10 in the fourth pipe, the solid waste in the airflow is filtered and collected.

[0035] Preferably, the tower body 32 of the evaporation separation tower has a contraction angle of 5 to 15°. During operation, the temperature inside the evaporation separation tower 3 is 100 to 150°C.

[0036] As a preferred example, the top 31 of the evaporation separation tower includes a first expansion portion 311, a middle portion 312, a second expansion portion 313 and a connecting portion 314 connected sequentially from top to bottom; the diameter of the first expansion portion 311 gradually increases from top to bottom, the diameter of the second expansion portion 313 gradually increases from top to bottom, the middle portion 312 and the connecting portion 314 are both cylindrical, the bottom diameter of the first expansion portion 311, the top diameter of the second expansion portion 313, and the diameter of the middle portion 312 are all equal, and the bottom diameter of the second expansion portion 313 and the diameter of the connecting portion 314 are equal. More preferably, the first expansion portion 311, the middle portion 312, the second expansion portion 313 and the connecting portion 314 are integrally formed to form a whole piece. The diameter of the first expansion portion 311 gradually increases from top to bottom. The diameter of the second expansion portion 313 gradually increases from top to bottom. The middle portion 312 and the connecting portion 314 are cylindrical. The cylindrical middle portion 312 is provided to allow the second pipe to pass through the evaporation separation tower 3, so as to facilitate the installation of the second pipe. The cylindrical connecting portion 314 is provided to connect the top 31 of the evaporation separation tower with the tower body 32. Figure 2 As described, the top 31 of the evaporation separation tower can be connected to the tower body 32 by a connecting flange. The first expansion portion 311 and the second expansion portion 313 are both in the shape of a trumpet with a small top and a large bottom, in order to reduce the speed of the airflow, so that the hot air can be more fully mixed with the mist electroplating wastewater, so that the water in the mist electroplating wastewater evaporates faster. The airflow flowing through the vortex fan 1 and the electric heater 2 has a faster speed after entering the top 31 of the evaporation separation tower. The airflow velocity is reduced by the first expansion portion 311 and the second expansion portion 313.

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

[0038]

[0039] Among them, v drepresents the droplet velocity in m / s; H represents the height of the tower body 32 in m; g represents the gravitational acceleration in m / s 2 ρ a Indicates the air density in the evaporation separation tower 3, in kg / m 3 ρ d Indicates the density of the droplets sprayed from the pressure nozzle 9, in kg / m 3 ; r d represents the radius of the droplets sprayed by the pressure nozzle 9, in m; ψ represents the resistance coefficient of the droplets in the evaporation separation tower 3, dimensionless; v a represents the speed of air in the tower body 32, in m / s. Wherein, ψ is calculated according to formula (2):

[0040]

[0041] Among them, Re is the Reynolds number of electroplating wastewater, which is a dimensionless coefficient.

[0042] By calculating the height of the tower body 32 of the evaporation separation tower according to formula (1), the electroplating wastewater can flow from top to bottom in the tower body 32 to the bottom of the tower body after entering the evaporation separation tower 3, thereby achieving complete evaporation and separation of the electroplating wastewater in the tower body.

[0043] In the embodiment of the present invention, the treatment device can be divided into two processes: the electroplating wastewater process and the hot air process. Among them, the hot air process is: the external ambient air extracted by the vortex fan 1 enters the electric heater 2, and after the temperature rises to the required temperature, the hot air enters the evaporation separation tower 3; the hot air entering the evaporation separation tower 3 first passes through the first expansion part and the second expansion part to reduce the flow speed, so as to exchange heat more evenly with the electroplating wastewater spray; flows through the tapered tower body 32, reduces the pressure, and after completing the heat exchange, it is directed upward by the fourth pipeline at the bottom of the tower body 32, and the waste gas and the metal salt particles are initially separated by the physical structure, and the waste gas flows out of the evaporation separation tower 3. The electroplating wastewater process is: the electroplating wastewater first passes through the flow calibration column 4 to measure the flow rate, and then is pressurized by the diaphragm pump 6 and reaches the pressure nozzle 9, and after being atomized into a spray, it exchanges heat with the hot air flowing from above, so that the water in the electroplating wastewater is gradually evaporated, and metal salt particles are formed after evaporation and separation, and fall into the bottom of the tower.

[0044] The treatment device of the above embodiment or preferred example can operate at medium and low temperature (within 150°C), does not require special equipment, has low sealing requirements, few consumables, low material requirements, is simple and convenient, and has low operating costs. The treatment device uses air as a separation carrier to treat electroplating wastewater, and the separation carrier is easy to obtain and is basically not restricted by the environment.

[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 in the protection scope of the present invention.

Claims

1. A treatment device for evaporating and separating electroplating wastewater, characterized in that: The treatment device comprises a hot air component, an evaporation separation tower (3), an electroplating wastewater component, and an exhaust component, wherein: The evaporation separation tower (3) comprises a top (31), a tower body (32) and a base (33) which are connected in sequence from top to bottom; the hot air component is connected to the top (31) of the evaporation separation tower, the electroplating wastewater component is connected to the top (31) of the evaporation separation tower, and the exhaust component is connected to the lower part of the tower body (32) of the evaporation separation tower; and the tower body (32) of the evaporation separation tower gradually shrinks from top to bottom.

2. The device for treating electroplating wastewater by evaporation separation according to claim 1, characterized in that: The hot air component comprises a vortex fan (1) and an electric heater (2); the vortex fan (1) is connected to the top (31) of the evaporation separation tower through a first pipeline, and the electric heater (2) is connected in the first pipeline.

3. The device for treating electroplating wastewater by evaporation and separation according to claim 1, characterized in that: The electroplating wastewater component comprises a flow calibration column (4), a liquid storage tank (5), a diaphragm pump (6) and a pressure nozzle (9); the outlet of the liquid 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 pipeline; the second pipeline passes through the top (31) of the evaporation separation tower; and the pressure nozzle (9) is located at the upper part of the inner cavity of the evaporation separation tower (3).

4. The device for treating electroplating wastewater by evaporation separation according to claim 3, characterized in that: The electroplating wastewater component further comprises a safety valve (7), wherein the safety valve (7) is connected to the second pipeline via a third pipeline; the liquid outlet end of the third pipeline is located above the liquid storage tank (5).

5. The device for treating electroplating wastewater by evaporation separation according to claim 3, characterized in that: The electroplating wastewater component also includes a pulse damper (8) located outside the evaporation separation tower (3), and the pulse damper (8) is connected to the top end of the branch, and the bottom end of the branch is connected to the top end of the second pipeline.

6. The device for treating electroplating wastewater by evaporation separation according to claim 1, characterized in that: The exhaust assembly comprises a fourth pipe and a bag filter (10) located outside the evaporative separation tower (3); the fourth pipe passes through the evaporative separation tower (3); an air inlet of the fourth pipe is located at the lower part of the inner cavity of the evaporative separation tower (3); the bag filter (10) is connected to the fourth pipe; and an air outlet of the fourth pipe is located outside the evaporative separation tower (3).

7. The device for treating electroplating wastewater by evaporation and separation according to claim 1, characterized in that: The tower body (32) of the evaporation separation tower has a contraction angle of 5 to 15 degrees.

8. The device for treating electroplating wastewater by evaporation and separation according to claim 1, characterized in that: The top (31) of the evaporation separation tower comprises a first expansion portion (311), a middle portion (312), a second expansion portion (313) and a connecting portion (314) which are sequentially connected from top to bottom; the diameter of the first expansion portion (311) gradually increases from top to bottom, the diameter of the second expansion portion (313) gradually increases from top to bottom, the middle portion (312) and the connecting portion (314) are both cylindrical, the bottom diameter of the first expansion portion (311), the top diameter of the second expansion portion (313) and the diameter of the middle portion (312) are all equal, and the bottom diameter of the second expansion portion (313) and the diameter of the connecting portion (314) are equal.

9. The device for treating electroplating wastewater by evaporation and separation according to claim 1, characterized in that: The height of the tower body (32) of the evaporation separation tower is calculated according to formula (1): Among them, v d represents the droplet velocity, in m / s; H represents the height of the tower body (32), in m; g represents the gravitational acceleration, in m / s 2 ρ a It represents the air density in the evaporation separation tower (3), in kg / m 3 ρ d It indicates the density of the droplets sprayed by the pressure nozzle (9), in kg / m 3 ; r d represents the radius of the droplets sprayed by the pressure nozzle (9), in meters; ψ represents the resistance coefficient of the droplets in the evaporation separation tower (3), dimensionless; v a It represents the speed of air in the tower body (32), in m / s.

10. The device for treating electroplating wastewater by evaporation and separation according to claim 1, characterized in that: During operation, the temperature inside the evaporation separation tower (3) is 100-150°C.

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