Treatment system and method for acid mist and distillate water generated by acid concentration and evaporation

Abstract

The invention discloses a treatment system and method for acid mist and distillate water generated by acid concentration and evaporation, and belongs to the technical field of green chemical industry. The method comprises the following steps: carrying out reduced pressure distillation on dilute acid in an acid concentration kettle, forming fraction water from fraction through a condenser, and feeding the fraction water into an alkalization kettle; uncondensed acid mist is pumped into the water tank through the water-ring vacuum pump; liquid alkali is added into the alkalization kettle and pumped into a water tank through a centrifugal pump, acid mist is retained in the water tank and absorbed by dilute alkali liquor, when a water phase in the water tank overflows into the alkalization kettle and high-concentration acid is completely discharged, dilute acid continues to be fed into an acid concentration kettle, the content of sodium sulfate and alkali in liquid in the alkalization kettle is detected regularly in the continuous concentration process, and the liquid alkali is added regularly; liquid in the alkalization kettle is discharged from the bottom of the kettle. The whole set of process for treating distilled water and acid mist generated in the acid concentration process realizes cyclic utilization and continuous treatment, conforms to the concept of green sustainable development, is good in acid concentration effect and sufficient in tail gas emission and absorption, and does not cause environmental pollution.

Description

Technical Field

[0001] The invention relates to the technical field of green chemical industry, and more particularly to a system and method for treating acid mist and distillate water generated by acid concentration and evaporation. Background Art

[0002] In the chemical production process, acid concentration and evaporation process is an important means of purifying acid, but the acid concentration and evaporation operation will produce a large amount of acid mist and distillate water mixture, which pollutes the ecological environment and cannot be discharged directly, but needs to be purified. The commonly used purification process now adopts intermittent collection and treatment device, which is not only not environmentally friendly, but also greatly increases production costs.

[0003] Therefore, how to develop a system and method for treating acid mist and distillate water produced by acid concentration and evaporation is an urgent problem to be solved by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides a system and method for treating acid mist and distillate water generated by acid concentration and evaporation.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A treatment system for acid mist and distillate water generated by acid concentration and evaporation, comprising an acid concentration kettle, a condenser, an alkalization kettle, a water ring vacuum pump, a water tank and a centrifugal pump, wherein the top of the acid concentration kettle is provided with a distillate outlet, one end of the condenser is provided with a distillate inlet, the other end of the condenser is provided with an acid mist outlet and a condensate outlet, an overflow port is provided at the upper part of the side wall of the water tank, an alkalization liquid inlet is provided at the bottom of the water tank, a neutralization liquid inlet and a condensate water inlet are provided at the top of the alkalization kettle, and an alkalization liquid outlet and a discharge and renewal port are provided at the bottom of the alkalization kettle;

[0007] The distillate outlet of the acid concentration kettle is connected to the distillate inlet of the condenser via a pipeline, the acid mist outlet of the condenser is connected to the air inlet of the water ring vacuum pump via a pipeline, the bottom of the water ring vacuum pump is sealed and connected to the top opening of the water tank, and the air outlet of the water ring vacuum pump is arranged in the water phase in the water tank, the overflow port of the water tank is connected to the neutralization liquid inlet of the alkalization kettle via a pipeline, and the alkalized liquid outlet of the alkalization kettle, the centrifugal pump and the alkalized liquid inlet of the water tank are connected in sequence via a pipeline;

[0008] The condensate outlet of the condenser is connected to the condensate inlet of the alkalization kettle via a pipeline.

[0009] Beneficial effects of the present invention: the acid concentration kettle of the present invention serves as an acid concentration production device, the condenser serves to liquefy the distilled fraction in the acid concentration kettle, the water ring vacuum pump serves to reduce the vacuum degree in the acid concentration kettle, the water tank serves to absorb the acid mist distilled out by reduced pressure in the acid concentration kettle, and at the same time provides circulating water for the water pump, and the alkalization kettle serves to receive the condensate liquefied by the condenser and the overflow liquid of the water tank. In order to absorb the acid mist, liquid alkali needs to be added to adjust the liquid in the alkalization kettle to be weakly alkaline, the bottom of the water ring vacuum pump is sealed and connected to the top opening of the water tank, and the air outlet of the water ring vacuum pump is arranged in the water phase in the water tank, which can prevent the leakage of the acid mist, and the centrifugal pump serves to pump the neutralization liquid in the alkalization kettle into the water tank, continuously replace the water in the water tank, and prevent the pH value in the water tank from being too low or affecting the absorption rate of the acid mist.

[0010] The present invention is a complete system for treating distilled water and acid mist generated in the acid concentration process, which can realize the recycling and continuous treatment of acid mist and distillate water generated by acid concentration evaporation, conforms to the concept of green and sustainable development, has good acid concentration effect, fully absorbs tail gas emissions, and will not cause environmental pollution.

[0011] Furthermore, an emptying port is provided at the bottom of the water tank, and a liquid inlet is provided at the upper part of the side wall of the alkalization kettle. The emptying port of the water tank is connected to the liquid inlet of the alkalization kettle via a pipeline. The water ring vacuum pump includes a motor, a paddle and a pump casing. The motor in the pump casing drives the paddle to rotate reciprocatingly. The water phase in the water tank provides circulating water for the water ring vacuum pump.

[0012] The beneficial effect of adopting the above-mentioned further technical solution is: this liquid inlet is connected to the bottom of the water ring vacuum pump water tank, and this pipe is an emptying pipe. When the device is out of use or repaired, the water ring vacuum pump water tank needs to be completely emptied and this pipe is used. It is not needed during normal operation.

[0013] Furthermore, it also includes a finished product tank, a feed port is provided on one side of the acid concentration kettle, a discharge port is provided at the bottom of the acid concentration kettle, and the discharge port of the acid concentration kettle is connected to the finished product tank via a pipeline.

[0014] The beneficial effect of adopting the above further technical solution is: the feed inlet on one side of the acid concentration kettle is the inlet for the raw material dilute acid, and the bottom discharge port is connected to the finished product tank for discharging the material after reaching the concentration.

[0015] Furthermore, the inner lining of the acid concentration kettle is made of enamel material, with a jacket structure in the middle, and heat transfer oil exists inside the jacket.

[0016] Beneficial effects of adopting the above further technical solution: Since the acid concentration kettle needs to contact the acidic liquid, the inner lining is made of enamel material. Since the acid concentration kettle needs to control the temperature to evaporate the water, heat transfer oil is used for heat conduction. The reason for not using high-temperature water for heating is that the oil temperature is higher than the water temperature.

[0017] Furthermore, the condenser has a jacket structure inside, and there is 0-2°C condensed water inside the jacket.

[0018] The beneficial effects of adopting the above further technical solution are: the temperature cannot be less than 0°C, because water will freeze, and too high a temperature will cause poor condensation effect.

[0019] The present invention also provides a method for treating acid mist and distillate water generated by acid concentration and evaporation, comprising the following steps:

[0020] (1) using the above-mentioned acid concentration and evaporation to produce acid mist and distillate water treatment system, the dilute acid is sent to the acid concentration kettle for vacuum distillation, the distillate is condensed by the condenser to form distillate water, and the distillate water enters the alkalization kettle;

[0021] (2) The uncondensed gas phase in the condenser forms acid mist and is pumped into the water tank through a water ring vacuum pump. At the same time, the water phase in the water tank provides circulating water for the water ring vacuum pump.

[0022] (3) adding dilute alkali to the alkalization kettle, pumping the dilute alkali in the alkalization kettle into the water tank of the water ring vacuum pump through a centrifugal pump, and the acid mist is retained in the water tank and absorbed by the dilute alkali. When the water level in the water tank reaches the overflow level, the water phase overflows and flows back to the alkalization kettle, and the high-concentration acid is discharged from the bottom of the acid concentration kettle and sent to the finished product tank. After the high-concentration acid is discharged, the dilute acid continues to be sent to the acid concentration kettle to achieve continuous concentration;

[0023] (4) During the continuous concentration process, the sodium sulfate and alkali content in the alkalization kettle liquid is regularly detected, and liquid alkali is regularly added. When the liquid in the alkalization kettle reaches 80-90% of the maximum liquid level and the salt reaches the saturated concentration, the liquid in the alkalization kettle is discharged from the bottom of the kettle.

[0024] Beneficial effects of the invention: The invention provides a complete process for treating distilled water and acid mist generated during the acid concentration process, which realizes recycling and continuous treatment process from the entry of dilute acid into the acid concentration kettle to the treatment of distilled water and acid mist, conforms to the concept of green and sustainable development, has good acid concentration effect, fully absorbs tail gas emissions, and does not cause environmental pollution.

[0025] Furthermore, in step (1), the dilute acid is dilute sulfuric acid, and the concentration of the dilute acid is 40-60%.

[0026] Furthermore, in step (1), the operating temperature of the reduced pressure distillation in the acid concentration kettle is 100 to 150° C., and the pressure in the kettle is -0.07 to -0.1 MPa.

[0027] The beneficial effect of adopting the above further technical solution is that when the pressure is between -0.07 and -0.1 MPa and the temperature is between 100 and 150° C., the organic matter and water in the dilute acid can be effectively evaporated.

[0028] Furthermore, in step (1), the temperature of the condenser is controlled at 0-2°C.

[0029] The beneficial effects of adopting the above further technical solution are: it cannot be less than 0°C, the water will freeze. If the condenser temperature is too high, the condensation effect will be poor.

[0030] Furthermore, in step (2), the vacuum degree of the water ring vacuum pump is -0.07 to -0.1 MPa.

[0031] The beneficial effect of adopting the above further technical solution is: the water ring vacuum pump is a vacuum pump in the kettle, which ensures that the vacuum pressure in the acid concentration kettle is -0.07 to -0.1 MPa. This vacuum degree is conducive to the evaporation of organic matter and water.

[0032] Furthermore, in step (3), the above-mentioned dilute alkali solution is a NaOH solution with a concentration of 3 to 8 wt%.

[0033] The beneficial effects of adopting the above further technical solution are: the liquid alkali content cannot be too high, because if the content is too high, after absorbing organic matter and acid mist for a long time, the viscosity will be too high, which is not conducive to circulation. If the content is too low, the absorption effect will be poor and the frequency of water change will increase.

[0034] Further, in step (3), the flow rate of the centrifugal pump is 1 to 3 m 3 / h.

[0035] The beneficial effect of adopting the above further technical solution: control the flow rate at 1-3m 3 / h, the time for the acid mist to be absorbed by the dilute alkali in the water tank can be controlled to 1-2h to ensure that the acid mist is completely absorbed.

[0036] Furthermore, in step (3), the acid mist is absorbed by the dilute alkali solution in the water tank for 1 to 2 hours.

[0037] The beneficial effect of adopting the above further technical solution is: controlling the flow rate can regulate the absorption time of the acid mist in water, and 1-2 hours can ensure that the acid mist is completely absorbed. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention is a schematic structural diagram of a system for treating acid mist and distillate water produced by acid concentration and evaporation.

[0039] Figure 2 It is a schematic structural diagram of the water ring vacuum pump and water tank of the present invention.

[0040] Among them, 1-acid concentration kettle, 2-condenser, 3-alkalization kettle, 4-water ring vacuum pump, 5-water tank, 6-centrifugal pump, 7-finished product tank, 8-water phase, 9-air inlet end, 10-air outlet end, 11-motor, 12-blade, 13-pump casing. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] A system for treating acid mist and distillate water generated by acid concentration and evaporation, comprising an acid concentration kettle 1, a condenser 2, an alkalization kettle 3, a water ring vacuum pump 4, a water tank 5 and a centrifugal pump 6, wherein the top of the acid concentration kettle 1 is provided with a distillate outlet, one end of the condenser 2 is provided with a distillate inlet, the other end of the condenser 2 is provided with an acid mist outlet and a condensate outlet, an overflow port is provided at the upper part of the side wall of the water tank 5, an alkalization liquid inlet is provided at the bottom of the water tank 5, a neutralization liquid inlet and a condensate water inlet are provided at the top of the alkalization kettle 3, and an alkalization liquid outlet and a discharge and renewal port are provided at the bottom of the alkalization kettle 3;

[0043] The fraction outlet of the acid concentration kettle 1 is connected to the fraction inlet of the condenser 2 via a pipeline, the acid mist outlet of the condenser 2 is connected to the air inlet end 9 of the water ring vacuum pump 4 via a pipeline, the bottom of the water ring vacuum pump 4 is sealed and connected to the top opening of the water tank 5, and the air outlet 10 of the water ring vacuum pump 4 is arranged in the water phase 8 in the water tank 5, the overflow port of the water tank 5 is connected to the neutralization liquid inlet of the alkalization kettle 3 via a pipeline, and the alkalized liquid outlet of the alkalization kettle 3, the centrifugal pump 6 and the alkalized liquid inlet of the water tank 5 are connected in sequence via a pipeline;

[0044] The condensate outlet of the condenser 2 is connected to the condensate inlet of the alkalization kettle 3 via a pipeline.

[0045] In one embodiment, a drain port is provided at the bottom of the water tank 5, and a liquid inlet is provided at the upper part of the side wall of the alkalization kettle 3. The drain port of the water tank 5 is connected to the liquid inlet of the alkalization kettle 3 via a pipeline. The water ring vacuum pump 4 includes a motor 11, a paddle 12 and a pump casing 13. The motor 11 in the pump casing 13 drives the paddle 12 to rotate reciprocatingly. The water phase 8 in the water tank 5 provides circulating water for the water ring vacuum pump 4.

[0046] In one embodiment, a finished product tank 7 is further included. A feed port is provided on one side of the acid concentration kettle 1, and a discharge port is provided at the bottom of the acid concentration kettle 1. The discharge port of the acid concentration kettle 1 is connected to the finished product tank 7 via a pipeline.

[0047] In one embodiment, the inner lining of the acid concentration kettle 1 is made of enamel material, with a jacket structure in the middle, and heat transfer oil exists inside the jacket.

[0048] In one embodiment, the condenser 2 has a jacket structure inside, and there is 0-2° C. condensed water inside the jacket.

[0049] Example 1

[0050] The method for treating acid mist and distillate water generated by acid concentration and evaporation comprises the following steps:

[0051] (1) A system for treating acid mist and distillate water produced by acid concentration and evaporation of the present invention is used, wherein dilute sulfuric acid with a concentration of 40 wt% is fed into an acid concentration kettle 1 for vacuum distillation, the working temperature is 100° C., the pressure in the kettle is -0.1 MPa, the distillate is condensed by a condenser 2 to form distillate water, the temperature of the condenser 2 is controlled at 0-2° C., and the distillate water enters an alkalization kettle 3;

[0052] (2) The uncondensed gas phase in the condenser 2 forms acid mist and is pumped into the water phase 8 in the water tank 5 by the water ring vacuum pump 4. Meanwhile, the water phase 8 in the water tank 5 provides circulating water for the water ring vacuum pump 4. The vacuum degree of the water ring vacuum pump 4 is -0.1 MPa.

[0053] (3) Add 8 wt% NaOH solution to the alkalization kettle 3, and pump the dilute alkali solution in the alkalization kettle 3 into the water tank 5 of the water ring vacuum pump 4 through the centrifugal pump 6. The flow rate of the centrifugal pump 6 is 1m 3 / h, the acid mist is retained in the water tank 5 and absorbed by the dilute alkali solution. The time for the acid mist to be absorbed by the dilute alkali solution in the water tank 5 is 2h. When the water level in the water tank 5 reaches the overflow level, the aqueous phase 8 overflows and flows back to the alkalization kettle 3 to realize the recycling of the dilute alkali solution. The high-concentration acid is discharged from the bottom of the acid concentration kettle 1 and sent to the finished product tank 7. After the high-concentration acid is discharged, the dilute acid continues to be sent to the acid concentration kettle 1 to realize continuous concentration;

[0054] (4) During the continuous concentration process, the sodium sulfate and alkali contents in the liquid in the alkalization kettle 3 are regularly detected, and liquid alkali is regularly added. After 6 months, when the liquid in the alkalization kettle 3 reaches 80% of the maximum liquid level and the sodium sulfate concentration reaches 8wt% and has no ability to absorb acid mist, the liquid in the alkalization kettle 3 is discharged from the bottom of the kettle.

[0055] Example 2

[0056] The method for treating acid mist and distillate water generated by acid concentration and evaporation comprises the following steps:

[0057] (1) A system for treating acid mist and distillate water produced by acid concentration and evaporation of the present invention is used, wherein 50 wt% dilute sulfuric acid is fed into an acid concentration kettle 1 for vacuum distillation, the working temperature is 100° C., the pressure in the kettle is -0.1 MPa, the distillate is condensed by a condenser 2 to form distillate water, the temperature of the condenser 2 is controlled at 0-2° C., and the distillate water enters an alkalization kettle 3;

[0058] (2) The uncondensed gas phase in the condenser 2 forms acid mist and is pumped into the water phase 8 in the water tank 5 by the water ring vacuum pump 4. Meanwhile, the water phase 8 in the water tank 5 provides circulating water for the water ring vacuum pump 4. The vacuum degree of the water ring vacuum pump 4 is -0.1 MPa.

[0059] (3) Add 8 wt% NaOH solution to the alkalization kettle 3, and pump the dilute alkali solution in the alkalization kettle 3 into the water tank 5 of the water ring vacuum pump 4 through the centrifugal pump 6. The flow rate of the centrifugal pump 6 is 1m 3 / h, the acid mist is retained in the water tank 5 and absorbed by the dilute alkali solution. The time for the acid mist to be absorbed by the dilute alkali solution in the water tank 5 is 2h. When the water level in the water tank 5 reaches the overflow level, the aqueous phase 8 overflows and flows back to the alkalization kettle 3 to realize the recycling of the dilute alkali solution. The high-concentration acid is discharged from the bottom of the acid concentration kettle 1 and sent to the finished product tank 7. After the high-concentration acid is discharged, the dilute acid continues to be sent to the acid concentration kettle 1 to realize continuous concentration;

[0060] (4) During the continuous concentration process, the sodium sulfate and alkali contents in the alkalization kettle 3 are regularly detected, and liquid alkali is regularly added. After 5 months, when the liquid in the alkalization kettle 3 reaches 80% of the maximum liquid level and the sodium sulfate concentration reaches 8wt% and has no ability to absorb acid mist, the liquid in the alkalization kettle 3 is discharged from the bottom of the kettle.

[0061] Example 3

[0062] The method for treating acid mist and distillate water generated by acid concentration and evaporation comprises the following steps:

[0063] (1) A system for treating acid mist and distillate water produced by acid concentration and evaporation of the present invention is used, wherein dilute sulfuric acid with a concentration of 60% is sent into an acid concentration kettle 1 for vacuum distillation, the working temperature is 100° C., the pressure in the kettle is -0.1 MPa, the distillate is condensed by a condenser 2 to form distillate water, the temperature of the condenser 2 is controlled at 0-2° C., and the distillate water enters an alkalization kettle 3;

[0064] (2) The uncondensed gas phase in the condenser 2 forms acid mist and is pumped into the water phase 8 in the water tank 5 by the water ring vacuum pump 4. Meanwhile, the water phase 8 in the water tank 5 provides circulating water for the water ring vacuum pump 4. The vacuum degree of the water ring vacuum pump 4 is -0.1 MPa.

[0065] (3) Add 8 wt% NaOH solution to the alkalization kettle 3, and pump the dilute alkali solution in the alkalization kettle 3 into the water tank 5 of the water ring vacuum pump 4 through the centrifugal pump 6. The flow rate of the centrifugal pump 6 is 1m 3 / h, the acid mist is retained in the water tank 5 and absorbed by the dilute alkali solution. The time for the acid mist to be absorbed by the dilute alkali solution in the water tank 5 is 2h. When the water level in the water tank 5 reaches the overflow level, the aqueous phase 8 overflows and flows back to the alkalization kettle 3 to realize the recycling of the dilute alkali solution. The high-concentration acid is discharged from the bottom of the acid concentration kettle 1 and sent to the finished product tank 7. After the high-concentration acid is discharged, the dilute acid continues to be sent to the acid concentration kettle 1 to realize continuous concentration;

[0066] (4) During the continuous concentration process, the sodium sulfate and alkali contents in the liquid in the alkalization kettle 3 are regularly detected, and liquid alkali is regularly added. After 4 months, when the liquid in the alkalization kettle 3 reaches 80% of the maximum liquid level and the salt reaches the saturated concentration and has no ability to absorb the acidic condensate, the liquid in the alkalization kettle 3 is discharged from the bottom of the kettle.

[0067] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for treating acid mist and distillate water produced by acid concentration and evaporation, characterized in that: The invention comprises an acid concentration kettle, a condenser, an alkalization kettle, a water ring vacuum pump, a water tank and a centrifugal pump, wherein the top of the acid concentration kettle is provided with a distillate outlet, one end of the condenser is provided with a distillate inlet, the other end of the condenser is provided with an acid mist outlet and a condensed water outlet, the upper part of the side wall of the water tank is provided with an overflow port, the bottom of the water tank is provided with an alkalization liquid inlet, the top of the alkalization kettle is provided with a neutralization liquid inlet and a condensed water inlet, and the bottom of the alkalization kettle is provided with an alkalization liquid outlet and a discharge and renewal port; The distillate outlet of the acid concentration kettle is connected to the distillate inlet of the condenser via a pipeline, the acid mist outlet of the condenser is connected to the air inlet of the water ring vacuum pump via a pipeline, the bottom of the water ring vacuum pump is sealed and connected to the top opening of the water tank, and the air outlet of the water ring vacuum pump is arranged in the water phase in the water tank, the overflow port of the water tank is connected to the neutralization liquid inlet of the alkalization kettle via a pipeline, and the alkalized liquid outlet of the alkalization kettle, the centrifugal pump and the alkalized liquid inlet of the water tank are connected in sequence via a pipeline; The condensate outlet of the condenser is connected to the condensate inlet of the alkalization kettle via a pipeline.

2. A system for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 1, characterized in that: The bottom of the water tank is provided with an emptying port, the upper part of the side wall of the alkalization kettle is provided with a liquid inlet, the emptying port of the water tank is connected to the liquid inlet of the alkalization kettle through a pipeline, the water ring vacuum pump comprises a motor, a blade and a pump casing, the motor in the pump casing drives the blade to rotate reciprocatingly, and the water phase in the water tank provides circulating water for the water ring vacuum pump.

3. A system for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 1, characterized in that: It also comprises a finished product tank, a feed port is arranged on one side of the acid concentration kettle, a discharge port is arranged at the bottom of the acid concentration kettle, and the discharge port of the acid concentration kettle is connected with the finished product tank via a pipeline.

4. A method for treating acid mist and distillate water produced by acid concentration and evaporation, characterized in that: The following steps are involved: (1) using the acid mist and distillate water treatment system produced by acid concentration and evaporation according to any one of claims 1 to 3, sending the dilute acid into an acid concentration kettle for vacuum distillation, condensing the distillate through a condenser to form distillate water, and the distillate water entering an alkalization kettle; (2) The uncondensed gas phase in the condenser forms acid mist and is pumped into the water tank through a water ring vacuum pump. At the same time, the water phase in the water tank provides circulating water for the water ring vacuum pump. (3) adding dilute alkali to the alkalization kettle, pumping the dilute alkali in the alkalization kettle into the water tank of the water ring vacuum pump through a centrifugal pump, and the acid mist is retained in the water tank and absorbed by the dilute alkali. When the water level in the water tank reaches the overflow level, the water phase overflows and flows back to the alkalization kettle, and the high-concentration acid is discharged from the bottom of the acid concentration kettle and sent to the finished product tank. After the high-concentration acid is discharged, the dilute acid continues to be sent to the acid concentration kettle to achieve continuous concentration; (4) During the continuous concentration process, the sodium sulfate and alkali content in the alkalization kettle liquid is regularly detected, and liquid alkali is regularly added. When the liquid in the alkalization kettle reaches 80-90% of the maximum liquid level and the salt reaches the saturated concentration, the liquid in the alkalization kettle is discharged from the bottom of the kettle.

5. The method for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 4, characterized in that: In step (1), the dilute acid is dilute sulfuric acid, and the concentration of the dilute acid is 40-60%.

6. The method for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 4, characterized in that: In step (1), the operating temperature of the acid concentration kettle for vacuum distillation is 100 to 150°C, the pressure in the kettle is -0.07 to -0.1 MPa; and the condenser is controlled at a temperature of 0 to 2°C.

7. The method for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 4, characterized in that: In step (2), the vacuum degree of the water ring vacuum pump is -0.07 to -0.1 MPa.

8. The method for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 4, characterized in that: In step (3), the dilute alkali solution is a NaOH solution with a concentration of 3 to 8 wt%.

9. The method for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 4, characterized in that: In step (3), the centrifugal pump flow rate is 1 to 3 m 3 / h.

10. The method for treating acid mist and distillate water produced by acid concentration and evaporation according to claim 4, characterized in that: In step (3), the acid mist is absorbed by the dilute alkali solution in the water tank for 1 to 2 hours.

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