A device and method for treating wastewater having a high concentration of free ammonia and ammonium salts

Abstract

The application relates to a high-concentration wastewater treatment device and method containing free ammonia and ammonium salt, and relates to the technical field of wastewater treatment. The method comprises the following steps: feeding wastewater into an MVR evaporation crystallization system for preheating, feeding the preheated wastewater into a forced circulation heater for heating to obtain a feed liquid with high solid content, and feeding the feed liquid with qualified solid content into a crystallizer for crystallization; feeding ammonia-containing condensate water into the top of a rectifying tower, performing vapor-liquid exchange heat transfer on the ammonia-containing condensate water in the rectifying tower; rectifying the ammonia-containing condensate water, and discharging the feed liquid in the rectifying tower through a kettle liquid pump when the ammonia content of the ammonia-containing condensate water is less than a certain value. When the feed liquid in the rectifying tower is discharged, only a trace amount of ammonia is contained, and the ammonia-containing condensate water is less harmful when recycled.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a wastewater treatment device and method for high-concentration wastewater containing free ammonia and ammonium salts. Background Technology

[0002] High-salinity wastewater is recognized in the wastewater treatment industry as a highly challenging type of wastewater to treat. Due to the high concentration of salt ions in the wastewater, chloride ions are highly corrosive, calcium and magnesium ions are highly scaling, and sodium salts are highly soluble. At the same time, they also have inhibitory and toxic effects on microorganisms. Therefore, conventional treatment technologies cannot be used to treat high-salinity wastewater. Evaporation crystallization technology is required to separate the dissolved salts in the water into solid and liquid components, recycle the condensed clean water, and landfill or recycle the solidified crystallized salts to ultimately achieve zero discharge.

[0003] Currently, many high-salt wastewaters contain a large amount of free ammonia. The condensate produced by evaporation crystallization technology also contains a large amount of free ammonia, making it impossible to directly treat it biologically. Furthermore, improper treatment can pollute the atmosphere and harm people.

[0004] The traditional evaporation and crystallization process for high-salt wastewater containing free ammonia involves first passing the wastewater into a distillation column to remove ammonia. After the ammonia evaporates from the top of the distillation column, it enters an ammonia recovery unit. The ammonia-free ammonium chloride solution flows out from the bottom of the column and is then pumped by a bottom pump to an evaporation and crystallization unit for further evaporation and crystallization.

[0005] Currently, free ammonia still exists in the ammonium chloride solution after ammonia removal, and some ammonia gas will still be dissolved in the condensate evaporated from the evaporation crystallization device. This poses a significant hazard when the condensate containing ammonia is subsequently recycled. Summary of the Invention

[0006] In order to reduce free ammonia in condensate, this application provides a wastewater treatment device and method for high concentrations of free ammonia and ammonium salts.

[0007] In a first aspect, this application provides a method for treating wastewater containing high concentrations of free ammonia and ammonium salts, employing the following technical solution:

[0008] A method for treating wastewater containing high concentrations of free ammonia and ammonium salts includes the following steps:

[0009] S1: The wastewater raw liquid is fed into the MVR evaporation crystallization system for preheating. The preheated wastewater raw liquid is then fed into the forced circulation heater for heating to obtain a liquid with a high solid content. The liquid with the required solid content is then fed into the crystallizer for crystallization.

[0010] S2: The MVR evaporation crystallization system generates ammonia-containing condensate during the heating of the wastewater raw liquid. The ammonia-containing condensate is then introduced into the top of the distillation column, where vapor-liquid heat exchange occurs.

[0011] S3: The ammonia-containing condensate is distilled. The ammonia-containing condensate is heated in the distillation column, and ammonia gas is obtained after evaporation. The ammonia gas is then passed into a reboiler for heat exchange and liquefaction to obtain ammonia water. The ammonia water is then cooled by heat exchange and introduced into an ammonia water tank. If a portion of the ammonia water reaches a certain concentration, it is discharged from the ammonia water tank; if a portion of the ammonia water does not reach a certain concentration, it is refluxed back to the distillation column.

[0012] S4: The ammonia water that has not reached a certain concentration continues to evaporate in the distillation column. When the ammonia content of the ammonia-containing condensate is less than a certain value, the liquid in the distillation column is discharged by the bottom liquid pump.

[0013] Optionally, step S1 further includes: circulating and heating the feed solution whose concentration does not meet the standard in the MVR evaporation crystallization system.

[0014] Optionally, after step S1, the method further includes: passing the cooled and crystallized material into a centrifuge to separate the crystals from the liquid, and then transferring the liquid back into the wastewater stock solution, mixing it with the wastewater stock solution, and then re-entering the system for circulating evaporation.

[0015] Optionally, the specific construction steps of step S2 include: separating secondary steam from the crystallizer, introducing the secondary steam into the steam compressor for compression, and then introducing the secondary steam into the forced circulation heater to exchange heat with the feed liquid to form ammonia-containing condensate.

[0016] Optionally, the specific construction steps of step S4 include: the feed liquid in the distillation column is discharged from the bottom of the distillation column and enters the separator for gas-liquid separation. Then, the feed liquid is circulated by a forced circulation pump. The feed liquid with the required concentration is discharged from the system after heat exchange by the bottom liquid pump. The feed liquid with the required concentration is transported back to the wastewater raw liquid, mixed with the wastewater raw liquid, and then re-enter the system for circulation evaporation.

[0017] Optionally, after step S4, the method further includes: obtaining secondary steam through gas-liquid separation in a separator, passing the secondary steam into a steam compressor to reach the heat exchange temperature, and then passing the secondary steam into a distillation column, where the secondary steam exchanges heat with the ammonia-containing liquid in the distillation column to form ammonia-containing condensate.

[0018] Secondly, this application provides a wastewater treatment device for high concentrations of free ammonia and ammonium salts, employing the following technical solution:

[0019] A wastewater treatment device for high concentrations of free ammonia and ammonium salts includes an evaporation crystallization system and a distillation ammonia stripping system. The distillation ammonia stripping system includes a distillation column, which is connected to a reboiler. The reboiler is connected to a liquid preheater, which is connected to an ammonia water cooler. The ammonia water cooler is connected to an ammonia water tank, which is connected to a discharge pump and a reflux pump. The reflux pump is connected to the distillation column.

[0020] Optionally, the lower end of the distillation column is connected to a separator, the separator is connected to a forced circulation pump, the forced circulation pump is connected to a reboiler, the forced circulation pump is connected to a bottom liquid pump, and the bottom liquid pump is connected to a bottom liquid heat exchanger.

[0021] Optionally, the evaporation crystallization system includes a feed pump connected to a kettle liquid heat exchanger, which is connected to a liquid preheater, which is connected to a steam preheater, which is connected to a forced circulation heater, which is connected to a crystallizer, which is connected to a cooling tank, which is connected to a centrifuge, which is connected to a mother liquor tank, and the mother liquor tank is connected to a mother liquor reflux pump.

[0022] Optionally, the upper end of the crystallizer is connected to a steam compressor, which is connected to a forced circulation heater.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. Before the feed liquid is introduced into the distillation column, the feed liquid with the required solid content has already been introduced into the crystallizer for crystallization. Therefore, when the distillation column is running, the content of crystals inside is extremely low, which can effectively reduce the occurrence of crystallization and scaling during the ammonia stripping process in the distillation column. When the feed liquid in the distillation column is discharged, it contains only trace amounts of ammonia, so the harm is minimal when the condensate containing ammonia is recycled.

[0025] 2. Ammonia-containing condensate is introduced into the top of the distillation column, flowing downwards and exchanging heat with the secondary steam inside. During the heating of the condensate, ammonia gas evaporates, exiting from the top of the column and then entering the shell side of the reboiler for heat exchange. After passing through a liquid preheater and an ammonia cooler for further cooling, it enters the ammonia tank. A portion of the ammonia solution reaching a certain concentration is discharged from the system as product via a discharge pump. Another portion, also reaching a certain concentration, is returned to the distillation column. Some of this returned ammonia solution is used as compressor spray water to reduce the compressor's operating temperature, prevent overheating, protect the equipment, and extend its service life. The remaining portion is returned to the distillation column, allowing for more thorough contact and mass transfer with the materials inside, further improving the purity and quality of subsequent products.

[0026] 3. Gas-liquid separation is performed by a separator. The separated secondary steam is compressed by a steam compressor to reach the heat exchange temperature, thereby improving the steam quality. During the heat exchange process, the latent heat of the steam can be utilized more fully, reducing energy loss and improving the energy efficiency of the entire system. The steam is then fed into a distillation column, where it exchanges heat with the ammonia-containing liquid to form condensate. The bottom liquid is discharged from the bottom of the distillation column and enters the separator for gas-liquid separation. It is then circulated by a forced circulation pump. The bottom liquid that meets the concentration standard is pumped through the bottom liquid preheater for heat exchange before being discharged from the system. The bottom liquid that does not meet the concentration standard continues to circulate and evaporate within the system. This helps reduce the generation of wastewater and waste gas, meeting the requirements of environmental protection and sustainable development.

[0027] 4. The raw liquid is preheated sequentially through a feed pump, passing through a kettle preheater, a liquid preheater, and a steam preheater. This multi-stage preheating ensures the raw liquid is sufficiently preheated before entering the forced circulation evaporator, reducing the heat required by the evaporator and thus improving energy efficiency and reducing energy consumption. The raw liquid is then fed into the forced circulation evaporator for heating before entering the crystallizer. Liquids that do not meet the concentration requirements circulate and evaporate within the system, while liquids that meet the concentration requirements are discharged into a cooling crystallization tank. After cooling and crystallization, the liquid enters a centrifuge, where the crystals are separated and discharged from the system. The mother liquor from the centrifugation process enters a mother liquor tank. The mother liquor is then transported back to the raw liquid via a mother liquor return pump, where it mixes with the raw liquid and re-enters the system. This process enables resource recycling and achieves energy conservation and emission reduction. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a process for treating wastewater containing high concentrations of free ammonia and ammonium salts.

[0029] Figure 2 This is a schematic diagram of the S101 step in a wastewater treatment method for high concentrations of free ammonia and ammonium salts.

[0030] Figure 3 This is a schematic diagram of step S401 in a wastewater treatment method for high concentrations of free ammonia and ammonium salts.

[0031] Figure 4 This is a schematic diagram of a wastewater treatment device containing high concentrations of free ammonia and ammonium salts.

[0032] Explanation of reference numerals in the attached diagram: 1. Feed pump; 11. Boiler liquid heat exchanger; 12. Liquid preheater; 13. Steam preheater; 14. Forced circulation heater; 141. Condensate tank; 142. Spray pump; 15. Crystallizer; 151. Steam compressor; 16. Cooling tank; 17. Centrifuge; 18. Mother liquor tank; 19. Mother liquor reflux pump; 2. Distillation column; 21. Reboiler; 22. Ammonia water cooler; 23. Ammonia water tank; 24. Discharge pump; 25. Ammonia water reflux pump; 26. Separator; 27. Forced circulation pump; 28. Boiler liquid pump; 3. Storage tank; 31. Non-condensable gas condenser; 4. Compressor; 5. Condensate pump. Detailed Implementation

[0033] The present application will be further described in detail below with reference to all the accompanying drawings.

[0034] In one aspect, embodiments of this application disclose a method for treating wastewater containing high concentrations of free ammonia and ammonium salts.

[0035] A method for treating wastewater containing high concentrations of free ammonia and ammonium salts includes the following steps.

[0036] S1: The wastewater raw solution is fed into the MVR evaporation crystallization system for preheating. The preheated wastewater raw solution is then fed into a forced circulation heater for heating to obtain a liquid with a high solid content. The liquid with a solid content concentration of 30% or more is fed into a crystallizer for crystallization to obtain crystals with a water content of less than 6%. The liquid with a concentration of less than 30% continues to be circulated and heated in the MVR evaporation crystallization system. This ensures product quality and improves resource utilization and production efficiency.

[0037] S101: The cooled and crystallized material is fed into a centrifuge to separate the crystals from the liquid. The liquid is then transported back to the wastewater stock solution, mixed with the wastewater stock solution, and then re-entered into the system for circulation and evaporation. By achieving precise separation of the material, the purity of the subsequent products is improved.

[0038] S2: The crystallizer separates secondary steam, which is then introduced into the steam compressor for compression. The secondary steam is then introduced into the forced circulation heater to exchange heat with the feed liquid to form ammonia-containing condensate. The condensate with an ammonia content of 6% is introduced into the top of the distillation column, where the ammonia-containing condensate undergoes vapor-liquid heat exchange.

[0039] S3: The ammonia-containing condensate is distilled. The ammonia-containing condensate is heated in the distillation column, and ammonia gas is obtained after evaporation. The ammonia gas is then passed into a reboiler for heat exchange and liquefaction to obtain ammonia water. The ammonia water is then cooled by heat exchange and introduced into an ammonia water tank. If the ammonia content of some of the ammonia water reaches 24%, it is discharged from the ammonia water tank; if the ammonia content of some of the ammonia water does not reach 24%, it is refluxed back to the distillation column.

[0040] S4: Continue to evaporate the ammonia water with an ammonia content of less than 24% in the distillation column. When the ammonia content of the ammonia condensate is less than 24%, the liquid in the distillation column is discharged through the bottom liquid pump.

[0041] S401: The feed liquid in the distillation column is discharged from the bottom of the distillation column and enters the separator for gas-liquid separation. Then the feed liquid is circulated by a forced circulation pump. The feed liquid with an ammonia concentration of less than or equal to 10 ppm is discharged from the system after heat exchange by the bottom liquid pump. The feed liquid with an ammonia concentration greater than 10 ppm is transported back to the wastewater raw liquid, mixed with the wastewater raw liquid, and then re-enters the system for circulation evaporation.

[0042] The condensate discharged from the distillation column contains only trace amounts of ammonia, and the harm is minimal when the ammonia-containing condensate is recycled.

[0043] After gas-liquid separation in the separator, secondary steam is obtained. The secondary steam is then fed into the steam compressor to reach the heat exchange temperature. The secondary steam is then fed into the distillation column, where it exchanges heat with the ammonia-containing liquid to form ammonia-containing condensate. Step S3 is then repeated to feed the ammonia-containing condensate into the distillation column for further distillation, thereby improving resource utilization and production efficiency.

[0044] The working principle of the wastewater treatment method for high-concentration wastewater containing free ammonia and ammonium salts in this application embodiment is as follows: High-salt wastewater containing free ammonia first enters an MVR system for evaporation. After evaporation, the liquid with a solid content of 30% is discharged into a cooling tank for cooling and crystallization. Then, it is separated by a centrifuge, ultimately obtaining crystals with a water content of less than 6%. The condensate with an ammonia content of 6% generated during the evaporation process in the MVR system is used as raw material in a distillation column for distillation. Through distillation, ammonia water with an ammonia content of 24% is discharged from the top of the column. After heat exchange and cooling, part of it is discharged from the system as product, and the other part is returned to the distillation column as reflux. The bottom liquid in the column continuously circulates and evaporates within the system. When the ammonia content is less than 10 ppm, it is discharged from the system by a bottom liquid pump. The condensate discharged from the distillation column contains only trace amounts of ammonia, and the hazard of recycling the ammonia-containing condensate is minimal.

[0045] Secondly, this application discloses a wastewater treatment device for high concentrations of free ammonia and ammonium salts.

[0046] Reference Figure 4A wastewater treatment device for high concentrations of free ammonia and ammonium salts includes an evaporation crystallization system and a distillation ammonia stripping system. The evaporation crystallization system includes a feed pump 1, which is connected to a bottom liquid heat exchanger 11. The bottom liquid heat exchanger 11 is connected to a liquid preheater 12, which is connected to a steam preheater 13. The steam preheater 13 is connected to a forced circulation heater 14, which is connected to a crystallizer 15. The crystallizer 15 is connected to a cooling tank 16, which is connected to a centrifuge 17. The centrifuge 17 is connected to a mother liquor tank 18, which is connected to a mother liquor reflux pump 19. The raw liquid passes through the bottom liquid preheater, the liquid preheater, and the steam preheater 19 sequentially via the feed pump 1. The preheater 13 preheats the raw liquid through multi-stage preheating, ensuring it is fully preheated before entering the forced circulation evaporator. This reduces the heat required by the evaporator, thereby improving energy efficiency and reducing energy consumption. The raw liquid is then fed into the forced circulation evaporator for heating before entering the crystallizer 15. Liquids with insufficient concentration are circulated and evaporated within the system, while liquids with sufficient concentration are discharged into a cooling crystallization tank. After cooling and crystallization, the liquid enters the centrifuge 17, where the crystals are separated and discharged from the system. The mother liquor after centrifugation enters the mother liquor tank 18. The mother liquor is then transported to the raw liquid via the mother liquor return pump 19, where it is mixed with the raw liquid and re-enters the evaporation and crystallization system. This process enables resource recycling and achieves energy conservation and emission reduction.

[0047] Reference Figure 4 The distillation and ammonia stripping system includes a distillation column 2, which is connected to a compressor 4 and a reboiler 21. The reboiler 21 is connected to a liquid preheater 12, which is connected to an ammonia water cooler 22. The ammonia water cooler 22 is connected to an ammonia water tank 23, which is connected to a discharge pump 24 and an ammonia water reflux pump 25. The ammonia water reflux pump 25 is connected to the distillation column 2. The MVR evaporation and crystallization system generates ammonia-containing condensate during the heating of the wastewater raw liquid. This ammonia-containing condensate is introduced into the top of the distillation column 2 and flows downward within the column, exchanging heat with the secondary steam inside the column. The heating process of the ammonia-containing condensate... During the process, ammonia gas evaporates from the top of the column and then enters the shell side of the reboiler 21 for heat exchange. After passing through the liquid preheater 12 and the ammonia water cooler 22 for heat exchange and cooling, it enters the ammonia water tank 23. A portion of the ammonia water that reaches a certain concentration is discharged from the system as a product through the discharge pump 24. Another portion of the ammonia water that reaches a certain concentration is discharged through the ammonia water return pump 25. Some of it is used as water spray for the compressor 4 to reduce the operating temperature of the compressor 4, prevent the compressor 4 from overheating, and thus protect the equipment and extend its service life. The rest is returned to the distillation column 2 to allow it to have more sufficient contact and mass transfer with the material in the column, thereby further improving the purity and quality of the subsequent products.

[0048] Reference Figure 4The lower end of the distillation column 2 is connected to a separator 26, which is connected to a forced circulation pump 27. The forced circulation pump 27 is connected to a reboiler 21 and a bottom liquid pump 28, which is connected to a bottom liquid heat exchanger 11. Gas-liquid separation is performed through the separator 26. The separated secondary steam enters the steam compressor 151 for compression, reaching the heat exchange temperature and thus improving the quality of the steam. During the heat exchange process, the latent heat of the steam can be utilized more fully, reducing energy loss and improving the energy efficiency of the entire system. Then, the steam is fed into the distillation column 2, where it exchanges heat with the ammonia-containing liquid to form condensate. The bottom liquid is discharged from the bottom of the distillation column 2 and enters the separator 26 for gas-liquid separation. It is then circulated by the forced circulation pump 27. The bottom liquid with the required concentration flows through the bottom liquid pump 28 and passes through the bottom liquid preheater for heat exchange before being discharged from the system. The bottom liquid with the required concentration continues to circulate and evaporate within the system. This helps reduce the generation of wastewater and waste gas, meeting the requirements of environmental protection and sustainable development.

[0049] Reference Figure 4 The upper end of the crystallizer 15 is connected to a steam compressor 151, which is connected to a forced circulation heater 14. The crystallizer 15 separates secondary steam, which is then introduced into the steam compressor 151 for compression. The secondary steam is then introduced into the forced circulation heater 14 to exchange heat with the liquid to form ammonia-containing condensate.

[0050] Reference Figure 4 The forced circulation heater 14 is connected to a condensate tank 141, which is connected to a water spray pump 142. The condensate tank 141 is also connected to the distillation column 2. Part of the condensate is sprayed to the inlet of the steam compressor 151 through the water spray pump 142 to reduce the temperature of the steam compressor 151. The other part is sent to the distillation column 2 for distillation through the condensate pump 5. This can realize the recycling of resources and achieve the effect of energy saving and emission reduction.

[0051] Reference Figure 4 The wastewater treatment device also includes a storage tank 3 for storing non-condensable gases. The upper ends of the forced circulation heater 14 and the reboiler 21 are equipped with exhaust valves for discharging non-condensable gases. The upper end of the storage tank 3 is connected to a non-condensable gas condenser 31, and both the forced circulation heater 14 and the reboiler 21 are connected to the non-condensable gas condenser 31. The non-condensable gases generated by the MVR system are discharged through the forced circulation heater 14, and the non-condensable gases generated by the distillation system are discharged through the reboiler 21. After the two types of non-condensable gases are collected and mixed, they are cooled by cooling water through a cooling plate heat exchanger. The resulting liquid is stored in the storage tank 3, which is connected to a tail gas treatment device. The gas is discharged into the tail gas treatment device for treatment.

[0052] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for treating wastewater containing high concentrations of free ammonia and ammonium salts, comprising the following steps: S1: The wastewater raw liquid is fed into the MVR evaporation crystallization system for preheating. The preheated wastewater raw liquid is then fed into the forced circulation heater for heating to obtain a liquid with a high solid content. The liquid with a solid content of more than 30% is then fed into the crystallizer for crystallization. S2: The MVR evaporation crystallization system generates ammonia-containing condensate during the heating of the wastewater raw liquid. The ammonia-containing condensate is then introduced into the top of the distillation column, where vapor-liquid heat exchange occurs. S3: The ammonia-containing condensate is distilled. The ammonia-containing condensate is heated in the distillation column, and ammonia gas is obtained after evaporation. The ammonia gas is then passed into a reboiler for heat exchange and liquefaction to obtain ammonia water. The ammonia water is then cooled by heat exchange and introduced into an ammonia water tank. If part of the ammonia water reaches an ammonia content of 24%, it is discharged from the ammonia water tank; if part of the ammonia water does not reach an ammonia content of 24%, it is refluxed back to the distillation column. S4: The ammonia water with an ammonia content of less than 24% continues to evaporate in the distillation column. The liquid in the distillation column is discharged from the bottom of the distillation column and enters the separator for gas-liquid separation. Then the liquid is circulated by a forced circulation pump. The liquid with an ammonia concentration of less than or equal to 10 ppm is discharged from the system after heat exchange by the bottom liquid pump. The liquid with an ammonia concentration greater than 10 ppm is transported back to the wastewater raw liquid, mixed with the wastewater raw liquid, and then re-enters the system for circulation and evaporation. After step S1, there is also included: The cooled and crystallized material is fed into a centrifuge to separate the crystals from the liquid. The liquid is then fed back into the wastewater stock solution, mixed with the wastewater stock solution, and then re-enter the system for circulation and evaporation. The specific construction steps of step S2 include: separating secondary steam from the crystallizer, introducing the secondary steam into the steam compressor for compression, and then introducing the secondary steam into the forced circulation heater to exchange heat with the feed liquid to form ammonia-containing condensate. A wastewater treatment device for high concentrations of free ammonia and ammonium salts includes an evaporation crystallization system and a distillation ammonia stripping system, characterized in that: the distillation ammonia stripping system includes a distillation column (2), the distillation column (2) is connected to a reboiler (21), the reboiler (21) is connected to a liquid preheater (12), the liquid preheater (12) is connected to an ammonia water cooler (22), the ammonia water cooler (22) is connected to an ammonia water tank (23), the ammonia water tank (23) is connected to a discharge pump (24) and an ammonia water reflux pump (25), and the ammonia water reflux pump (25) is connected to the distillation column (2).

2. A process for the treatment of wastewater containing high concentrations of free ammonia and ammonium salts according to claim 1, characterized in that: Step S1 also includes: circulating and heating the feed solution with a concentration of less than 30% in the MVR evaporation crystallization system.

3. The method for treating high-concentration wastewater containing free ammonia and ammonium salts according to claim 1, characterized in that: After step S4, the process further includes: obtaining secondary steam through gas-liquid separation in a separator, passing the secondary steam into a steam compressor to reach the heat exchange temperature, and then passing the secondary steam into a distillation column. After the secondary steam exchanges heat with the ammonia-containing liquid in the distillation column, ammonia-containing condensate is formed.

4. The wastewater treatment method for high concentrations of free ammonia and ammonium salts according to claim 1, characterized in that: The lower end of the distillation column (2) is connected to a separator (26), the separator (26) is connected to a forced circulation pump (27), the forced circulation pump (27) is connected to a reboiler (21), the forced circulation pump (27) is connected to a bottom liquid pump (28), and the bottom liquid pump (28) is connected to a bottom liquid heat exchanger (11).

5. The wastewater treatment method for high concentrations of free ammonia and ammonium salts according to claim 4, characterized in that: The evaporation crystallization system includes a feed pump (1), which is connected to a kettle liquid heat exchanger (11). The kettle liquid heat exchanger (11) is connected to a liquid preheater (12), which is connected to a steam preheater (13). The steam preheater (13) is connected to a forced circulation heater (14), which is connected to a crystallizer (15). The crystallizer (15) is connected to a cooling tank (16), which is connected to a centrifuge (17). The centrifuge (17) is connected to a mother liquor tank (18), which is connected to a mother liquor reflux pump (19).

6. The wastewater treatment method for high concentrations of free ammonia and ammonium salts according to claim 5, characterized in that: The upper end of the crystallizer (15) is connected to a steam compressor (151), which is connected to a forced circulation heater (14).

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