Evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid

Abstract

The utility model discloses an evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid. Circulating outlets and circulating inlets of a third-effect separator and a second-effect separator are connected through a third-effect material circulating pipe, a second-effect material circulating pipe, a third-effect circulating pump, a second-effect circulating pump, a third-effect forced evaporator and a second-effect forced evaporator; a circulating outlet and a circulating inlet of the first-effect crystallizer are connected through a first-effect material circulating pipe, a first-effect circulating pump and a first-effect forced evaporator; an outlet of the ammonium sulfate wastewater pipe is connected with a triple-effect material circulating pipe through the cold sides of a product condensate water preheater and a product non-condensable gas preheater; an outlet of a triple-effect forced evaporator is connected with a double-effect material circulating pipe through a material transfer pipe; an outlet of the second-effect forced evaporator is connected with a first-effect material circulating pipe through a material transferring pipe; and a product crystal mush outlet of the first-effect crystallizer is connected with the mother liquor drying unit through a product crystal mush pipe. The system realizes effective separation of ammonium sulfate and carnallite, improves the utilization rate and output efficiency of ammonium sulfate, and improves the purity of the product ammonium sulfate.

Description

Technical Field

[0001] The utility model relates to a salt separation system, in particular to an evaporation concentration salt separation system for ammonium sulfate wastewater containing sulfuric acid, belonging to the technical field of comprehensive resource utilization. Background Art

[0002] Ammonium sulfate is an excellent nitrogen fertilizer (commonly known as fertilizer powder), suitable for general soil and crops. It can make branches and leaves grow vigorously, improve fruit quality and yield, and enhance the resistance of crops to disasters. It can be used as base fertilizer, topdressing and seed fertilizer. It is also a catalyst for food color, a nitrogen source for yeast cultivation in fresh yeast production, an auxiliary dye for acid dyeing, and a leather deashing agent. In addition, it is also used in beer brewing, chemical reagents and battery production. Another important role of ammonium sulfate is the mining of rare earths. Ammonium sulfate is used as a raw material for mining. The rare earth elements in the ore are exchanged in the form of ion exchange, and the leaching liquid is collected, impurities are removed, precipitated, pressed, and burned to form rare earth ore. About 5 tons of ammonium sulfate are required for each ton of rare earth ore produced. Ammonium sulfate plays an important role in my country's agricultural production and industrial modernization. How to separate qualified ammonium sulfate from industrial wastewater has become a research hotspot.

[0003] In industry, ammonium sulfate can be obtained by directly neutralizing ammonia and sulfuric acid. It is mainly used to absorb by-products or waste gases emitted in industrial production with sulfuric acid or ammonia water, such as sulfuric acid absorbing ammonia in coke oven gas, ammonia absorbing sulfur dioxide in smelter flue gas, ammonia in capron production or sulfuric acid waste liquid in sulfuric acid titanium dioxide production. When ammonium sulfate is produced industrially or sulfuric acid is used to remove toxic ammonia, ammonium sulfate wastewater containing sulfuric acid will be generated, which will cause great waste and pollute the surrounding environment. How to harmlessly treat the wastewater and generate economic benefits has become a difficult problem.

[0004] The Chinese invention patent application with publication number "CN114832424A" discloses a forced circulation ammonium sulfate evaporation crystallization device, which includes a concentration evaporation unit, an evaporation crystallization unit and a drying unit connected in sequence. An evaporator and a crystallizer are used to evaporate and crystallize the ammonium sulfate solution, and the ammonium sulfate crystals are centrifuged and dried.

[0005] However, the above technical solutions and the prior art have the following defects:

[0006] 1. The ammonium sulfate evaporation and crystallization system adopts single-effect evaporation concentration and single-effect crystallization process. Ammonium sulfate uses heat exchange medium to provide heat for evaporation and crystallization. The main heat exchange medium of the device is raw steam, and two shell-and-tube heat exchangers are used for heat exchange respectively. The raw steam has a large consumption without recycling design, and the economic efficiency of the device running the secondary steam between the two heat exchangers separately is poor.

[0007] 2. The mother liquor of ammonium sulfate crystal slurry after separation by centrifuge is not recycled, resulting in large loss of ammonium sulfate product and lack of economy and environmental protection.

[0008] 3. As evaporation proceeds, the non-precipitated ions in the mother liquor are continuously enriched, increasing the boiling point temperature rise of the mother liquor, greatly affecting the normal crystallization of ammonium sulfate, resulting in high energy consumption and low ammonium sulfate crystallization efficiency.

[0009] 4. The crystallization solution was not pretreated and the pH value was not adjusted before concentration. Impurities such as silicon, calcium and sludge would be caked on the inner wall of the heat exchange tube of the shell-and-tube heat exchanger, greatly affecting the heat exchange efficiency.

[0010] 5. For the separation of ammonium sulfate wastewater containing toxic and harmful substances such as sulfuric acid, the system does not have emergency accident handling measures. This scheme is not applicable to the extraction of ammonium sulfate from sulfuric acid-containing wastewater and has poor practicality. Utility Model Content

[0011] The purpose of this section is to summarize some aspects of the embodiments of the utility model and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and utility model name of this application to avoid blurring the purpose of this section, specification abstract and utility model name, and such simplifications or omissions cannot be used to limit the scope of the utility model.

[0012] In view of the above problems and / or problems existing in the prior art, the present utility model is proposed.

[0013] The purpose of the utility model is to overcome the problems existing in the prior art and provide an evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid, so as to achieve effective separation of sulfuric acid-containing wastewater, ammonium sulfate and miscellaneous salts, improve the utilization rate and output efficiency of ammonium sulfate, and improve the purity of the product ammonium sulfate.

[0014] In order to solve the above technical problems, the utility model provides an evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid, comprising a triple-effect separator, a second-effect separator and a first-effect crystallizer, wherein the circulation outlet of the triple-effect separator is connected to the inlet of a triple-effect circulation pump through a triple-effect material circulation pipe, and the outlet of the triple-effect circulation pump is connected to the circulation inlet of the triple-effect separator through a triple-effect forced evaporator;

[0015] The circulation outlet of the second-effect separator is connected to the inlet of the second-effect circulation pump through the second-effect material circulation pipe, and the outlet of the second-effect circulation pump is connected to the circulation inlet of the second-effect separator through the second-effect forced evaporator;

[0016] The circulation outlet of the first-effect crystallizer is connected to the inlet of the first-effect circulation pump through the first-effect material circulation pipe, and the outlet of the first-effect circulation pump is connected to the circulation inlet of the first-effect crystallizer through the first-effect forced evaporator;

[0017] The outlet of the ammonium sulfate wastewater pipe is connected to the cold side inlet of the product condensate water preheater, the cold side outlet of the product condensate water preheater is connected to the cold side inlet of the product non-condensable gas preheater, the cold side outlet of the product non-condensable gas preheater is connected to the three-effect material circulation pipe, the outlet of the three-effect forced evaporator is connected to the two-effect material circulation pipe through the three-effect to two-effect transfer pipe; the outlet of the two-effect forced evaporator is connected to the first-effect material circulation pipe through the second-effect to first-effect transfer pipe; the product slurry outlet of the first-effect crystallizer is connected to the mother liquor drying unit through the product slurry pipe.

[0018] As an improvement of the present utility model, the top air outlet of the triple-effect separator is connected to the inlet of the scrubbing tower, the outlet of the scrubbing tower is connected to the inlet of the steam compressor, the outlet of the steam compressor is connected to the upper inlet of the shell side of the single-effect forced evaporator through a secondary steam circulation pipe, the top air outlet of the single-effect crystallizer is connected to the upper inlet of the shell side of the double-effect forced evaporator, and the top air outlet of the double-effect separator is connected to the upper inlet of the shell side of the triple-effect forced evaporator.

[0019] As a further improvement of the utility model, the lower shell outlet of the first-effect forced evaporator is connected to the first-effect condensate water tank, the lower shell outlet of the second-effect forced evaporator is connected to the second-effect condensate water tank, the lower shell outlet of the triple-effect forced evaporator is connected to the triple-effect condensate water tank, the outlets of the first-effect condensate water tank, the second-effect condensate water tank and the triple-effect condensate water tank are all connected to the inlet of the product condensate water pump, the outlet of the product condensate water pump is connected to the hot side inlet of the product condensate water preheater, and the hot side outlet of the product condensate water preheater is connected to the triple-effect crystallization flushing pipe.

[0020] As a further improvement of the present utility model, the shell-side non-condensable gas outlets of the first-effect forced evaporator, the second-effect forced evaporator and the third-effect forced evaporator are all connected to the hot side inlet of the product non-condensable gas preheater through the product non-condensable gas pipe, the hot side outlet of the product non-condensable gas preheater is connected to the hot side inlet of the product surface cooler, the hot side outlet of the product surface cooler is connected to the product vacuum pump, the cooling water replenishment pipe is connected to the cold side inlet of the product surface cooler, and the cold side outlet of the product surface cooler is connected to the circulation pipe of the scrubbing tower.

[0021] As a further improvement of the utility model, in the mother liquor drying unit: the outlet of the product slurry tube is connected to the product thickening tank, the bottom flow outlet of the product thickening tank is connected to the inlet of the product centrifuge, the solid phase outlet of the product centrifuge is connected to the inlet of the vibrating fluidized bed, and the outlet of the vibrating fluidized bed is connected to the dry product external transport pipe.

[0022] As a further improvement of the utility model, the overflow outlet of the product thickening tank is connected to the secondary sedimentation tank, the underflow outlet of the secondary sedimentation tank and the liquid phase outlet of the product centrifuge are respectively connected to the mother liquid tank, and the outlet of the mother liquid tank is connected to the tube reflux port of the first-effect forced evaporator through a mother liquid reflux pump; the outlet of the mother liquid reflux pump is connected to the accident pool through a material emergency discharge pipe.

[0023] As a further improvement of the utility model, the overflow outlet of the secondary sedimentation tank is connected to the cold side inlet of the single-effect condensate preheater through a clear liquid discharge pump, the cold side outlet of the single-effect condensate preheater is connected to the single-effect circulation pipe, the outlet of the single-effect circulation pipe is connected to the circulation inlet of the single-effect crystallizer, the circulation outlet of the single-effect crystallizer is connected to the tube side inlet of the single-effect forced evaporator, the tube side outlet of the single-effect forced evaporator is connected to the inlet of the single-effect circulation pump, and the outlet of the single-effect circulation pump is connected to the single-effect circulation pipe.

[0024] As a further improvement of the utility model, the mixed salt slurry outlet of the single-effect crystallizer is connected to the mixed salt thickening tank through a mixed salt slurry pump, the bottom flow outlet of the mixed salt thickening tank is connected to the inlet of the mixed salt centrifuge, and the solid phase outlet of the mixed salt centrifuge is connected to the mixed salt outlet pipe.

[0025] As a further improvement of the utility model, the liquid phase outlet of the impure salt centrifuge is connected to the inlet of the drum dryer, and the outlet of the drum dryer is connected to the dry impure salt outlet pipe.

[0026] As a further improvement of the utility model, the top air outlet of the single-effect crystallizer is connected to the injection port of the steam jet pump, the main inlet of the steam jet pump is connected to the raw steam replenishment pipe, the outlet of the steam jet pump is connected to the shell side inlet of the single-effect forced evaporator, the shell side outlet of the single-effect forced evaporator is connected to the single-effect condensate water tank, the outlet of the single-effect condensate water tank is connected to the hot side inlet of the single-effect condensate water preheater through the single-effect condensate water pump, and the hot side outlet of the single-effect condensate water preheater is connected to the single-effect flushing pipe.

[0027] Compared with the prior art, the utility model has achieved the following beneficial effects: 1. The utility model separates ammonium sulfate and impurities from sulfuric acid-containing wastewater, solves the effective separation of sulfuric acid-containing wastewater and ammonium sulfate, and the nitrogen content of the product is ≥20.5%, and the sulfur content is ≥24.0%. The ammonium sulfate product meets the fertilizer-grade ammonium sulfate type I index in GB / T535-2020 and reaches the sales grade.

[0028] 2. This system is equipped with a secondary preheating unit, an MVR product evaporation crystallization unit, a single-effect TVR salt crystallization unit, a mother liquor drying unit, and an accident material collection and transmission system. It rationally utilizes the latent heat of secondary steam, the heat of condensed water, and the general law of ammonium sulfate solubility, effectively avoids the influence of phosphate enrichment on the increase of the boiling point of wastewater, improves the utilization efficiency of raw steam and the output efficiency and cleanliness of ammonium sulfate, and saves more energy than traditional evaporation crystallization.

[0029] 3. The utility model adds a secondary precipitation system. The ammonium sulfate dilute material in the product thickening tank is transported to the secondary precipitation tank through the overflow pipe. The cannula in the secondary precipitation tank is inserted into the bottom of the precipitation tank to precipitate the raw crystals. The clear water on the upper layer of the secondary precipitation tank is transported out through the overflow port, so as to effectively separate the unprecipitated mother liquor in the ammonium sulfate solution.

[0030] 4. The utility model adds a mixed salt TVR single-effect crystallization system, which discharges the phosphate-rich ammonium sulfate wastewater from the overflow port of the secondary sedimentation tank to the TVR evaporation crystallization unit, effectively avoiding the enrichment of mixed salts and raising the boiling point of the material, thereby reducing the load of the steam compressor and improving the efficiency of ammonium sulfate evaporation and crystallization; the discharged phosphate-rich mother liquor enters the single-effect TVR system for further evaporation and crystallization, and then the mixed salt is separated from the solid by the mixed salt centrifuge, and the liquid mother liquor outlet of the mixed salt centrifuge enters the drum dryer for forced drying.

[0031] 5. The output of ammonium sulfate products of the utility model mainly relies on a set of three-effect evaporation crystallization system. The heat exchange mode of this system is countercurrent heat exchange. The flow direction of the material and the heating steam is opposite. The temperature difference of the two heat exchange fluids gradually increases, thereby ensuring the heat transfer efficiency; at the same time, it has the advantages of small heat exchange loss and high efficiency, effectively reducing the heat exchange area of ​​the three forced evaporators and reducing equipment costs.

[0032] 6. In the utility model, both vacuum pumps are water ring vacuum pumps, the temperature rise is kept within 14°C, and the working fluid is produced water, which greatly reduces the pollution of the system to the environment; and the water seal effect of the water ring vacuum pump is used to adsorb sulfuric acid or ammonia water that may leak from the upstream to prevent pollution of the atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. The drawings are only provided for reference and explanation, not for limiting the present utility model. Among them:

[0034] Figure 1 This is a flow chart of the evaporation concentration separation system in the utility model;

[0035] In the figure: 16. Product condensate preheater; 17. Product non-condensable gas preheater; 18. Three-effect forced evaporator; 19. Three-effect separator; 20. Three-effect condensate tank; 21. Two-effect forced evaporator; 22. Two-effect separator; 23. Two-effect condensate tank; 24. One-effect forced evaporator; 25. One-effect crystallizer; 26. One-effect condensate tank; 27. Product surface cooler; 28. Scrubber; 29. ​​Steam compressor; 30. Product thickening tank; 31. Product centrifuge; 32. Vibrating fluidized bed; 33. Mother liquor tank; 34. Secondary precipitation tank; 35. Single-effect condensate preheater; 36. Single-effect forced evaporator; 37. Single-effect crystallizer; 38. Single-effect condensate tank; 39. Steam jet pump; 40. Single-effect surface cooler; 41. Miscellaneous salt thickening tank; 42. Miscellaneous salt centrifuge; 43. Drum dryer;

[0036] B7. Triple-effect circulation pump; B8. Double-effect circulation pump; B9. Single-effect circulation pump; B10. Washing water circulation pump; B11. Product vacuum pump; B12. Product condensate pump; B13. Product slurry pump; B14. Mother liquor reflux pump; B15. Clear liquor effluent pump; B16. Single-effect circulation pump; B17. Single-effect condensate pump; B18. Miscellaneous salt slurry pump; B19. Single-effect vacuum pump;

[0037] G3. Ammonium sulfate wastewater pipe; G11. Material emergency discharge pipe; G13. Three-effect material circulation pipe; G14. Three-effect to two-effect transfer pipe; G15. Two-effect material circulation pipe; G16. Two-effect to one-effect transfer pipe; G17. One-effect material circulation pipe; G18. Product condensate pipe; G19. Three-effect crystallization flushing pipe; G20. Product non-condensable gas pipe; G21. Product non-condensable gas external discharge pipe; G22. Cooling water replenishment pipe; G23. Washing water circulation pipe; G24. Terminal secondary steam delivery pipe; G25. Secondary steam circulation pipe; G26. One-effect to two-effect secondary steam pipe; G27. Two-effect to three-effect secondary steam pipe; G28. Product slurry pipe; G29. Product Thick pipe; G30. Viscous material pipe; G31. Dry product external transmission pipe; G32. Thick overflow pipe; G33. Sedimentation overflow pipe; G34. Sedimentation mother liquor pipe; G35. Product centrifuge liquid phase pipe; G36. Mother liquor collection pipe; G37. Mother liquor reflux pipe; G38. Single-effect circulation pipe; G39. Single-effect condensate pipe; G40. Single-effect flushing pipe; G41. Single-effect secondary steam circulation pipe; G42. Raw steam supplement pipe; G43. Single-effect slurry pipe; G44. Single-effect thick material discharge pipe; G45. Miscellaneous salt outlet pipe; G46. Mother liquor drying pipe; G47. Dry miscellaneous salt outlet pipe; G48. Single-effect non-condensable gas pipe; G49. Single-effect non-condensable gas external discharge pipe. DETAILED DESCRIPTION

[0038] In the following description of the utility model, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the utility model and simplifying the description, and do not mean that the device must have a specific direction.

[0039] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0041] like Figure 1 As shown, the evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid in the utility model is provided with a secondary preheating unit, an MVR product evaporation crystallization unit, a single-effect TVR miscellaneous salt crystallization unit, a mother liquor drying unit and an accident material collection and transmission system according to the material characteristics and industrial production requirements for the ammonium sulfate material.

[0042] The secondary preheating unit includes a product condensate preheater 16 and a product non-condensable gas preheater 17. The MVR product evaporation and crystallization unit includes a three-effect forced evaporator 18, a three-effect separator 19, a three-effect condensate tank 20, a two-effect forced evaporator 21, a two-effect separator 22, a two-effect condensate tank 23, a first-effect forced evaporator 24, a first-effect crystallizer 25, a first-effect condensate tank 26, a product surface cooler 27, a scrubber 28 and a steam compressor 29.

[0043] The single-effect TVR mixed salt crystallization unit includes a single-effect condensate preheater 35 , a single-effect forced evaporator 36 , a single-effect crystallizer 37 , a single-effect condensate tank 38 , a steam jet pump 39 and a single-effect surface cooler 40 .

[0044] The mother liquor drying unit includes a product thickening tank 30 , a product centrifuge 31 , a vibrating fluidized bed 32 , a mother liquor tank 33 , a secondary sedimentation tank 34 , a miscellaneous salt thickening tank 41 , a miscellaneous salt centrifuge 42 and a drum dryer 43 .

[0045] The clean ammonium sulfate-containing wastewater is sent to the cold side of the product condensate preheater 16 through the ammonium sulfate wastewater pipe G3, and then enters the cold side of the product non-condensable gas preheater 17. After being preheated in the product condensate preheater 16 and the product non-condensable gas preheater 17, the temperature rises by about 5°C and enters the three-effect material circulation pipe G13.

[0046] The liquid circulation outlet of the triple-effect separator 19 is connected to the inlet of the triple-effect circulation pump B7 through the triple-effect material circulation pipe G13, the outlet of the triple-effect circulation pump B7 is connected to the lower inlet of the tube side of the triple-effect forced evaporator 18, and the upper outlet of the tube side of the triple-effect forced evaporator 18 is connected to the liquid circulation inlet of the triple-effect separator 19. The liquid concentrated by the triple-effect separator 19 is transferred to the second-effect material circulation pipe G15 through the three-effect to second-effect transfer pipe G14.

[0047] Similarly, the liquid circulation outlet of the second-effect separator 22 is connected to the inlet of the second-effect circulation pump B8 through the second-effect material circulation pipe G15, the outlet of the second-effect circulation pump B8 is connected to the lower inlet of the tube side of the second-effect forced evaporator 21, and the upper outlet of the tube side of the second-effect forced evaporator 21 is connected to the liquid circulation inlet of the second-effect separator 22. The upper outlet of the tube side of the second-effect forced evaporator 21 is also connected to the first-effect material circulation pipe G17 through the second-effect to first-effect transfer pipe G16. The liquid concentrated by the second-effect separator 22 is transferred to the first-effect material circulation pipe G17 through the second-effect to first-effect transfer pipe G16.

[0048] Similarly, the liquid circulation outlet of the first-effect crystallizer 25 is connected to the inlet of the first-effect circulation pump B9 through the first-effect material circulation pipe G17, the outlet of the first-effect circulation pump B9 is connected to the lower inlet of the tube side of the first-effect forced evaporator 24, and the upper outlet of the tube side of the first-effect forced evaporator 24 is connected to the liquid circulation inlet of the first-effect crystallizer 25.

[0049] The slurry outlet of the first-effect crystallizer 25 is connected to the inlet of the product slurry pump B13 through the product slurry pipe G28, and the outlet of the product slurry pump B13 is connected to the top inlet of the product thickening tank 30. The slurry discharged from the first-effect crystallizer 25 is sent into the product thickening tank 30 through the product slurry pump B13, and the bottom flow outlet of the product thickening tank 30 is connected to the inlet of the product centrifuge 31 through the product thickening pipe G29, and the solid phase outlet of the product centrifuge 31 is connected to the inlet of the vibrating fluidized bed 32 through the viscous material pipe G30; after vibration drying in the vibrating fluidized bed 32, the qualified ammonium sulfate product is output through the dry product output pipe G31.

[0050] The liquid phase outlet of the product centrifuge 31 is connected to the inlet of the mother liquid tank 33 through the product centrifuge liquid phase pipe G35, the overflow port of the product thickening tank 30 is connected to the inlet of the secondary sedimentation tank 34 through the thickening overflow pipe G32, the bottom flow outlet of the secondary sedimentation tank 34 is connected to the inlet of the mother liquid tank 33 through the sedimentation mother liquid pipe G34, the outlet of the mother liquid tank 33 is connected to the inlet of the mother liquid reflux pump B14 through the mother liquid collecting pipe G36, and the outlet of the mother liquid reflux pump B14 is connected to the tube side reflux port of the first-effect forced evaporator 24 through the mother liquid reflux pipe G37.

[0051] The shell-side non-condensable gas outlets of the first-effect forced evaporator 24, the second-effect forced evaporator 21 and the third-effect forced evaporator 18 are all connected to the hot side inlet of the product non-condensable gas preheater 17 through the product non-condensable gas pipe G20, the hot side outlet of the product non-condensable gas preheater 17 is connected to the hot side inlet of the product surface cooler 27, the hot side outlet of the product surface cooler 27 is connected to the exhaust port of the product vacuum pump B11, and the exhaust port of the product vacuum pump B11 is connected to the atmosphere through the product non-condensable gas external exhaust pipe G21.

[0052] The cooling water replenishment pipe G22 is connected to the cold side inlet of the product surface cooler 27, the cold side outlet of the product surface cooler 27 is connected to the outlet pipe of the washing water circulation pump B10, the washing water circulation pipe G23 is connected to the upper spray port of the washing tower 28, and the bottom outlet of the washing tower 28 is connected to the inlet of the washing water circulation pump B10.

[0053] The shell-side condensate outlets of the first-effect forced evaporator 24, the second-effect forced evaporator 21 and the third-effect forced evaporator 18 are respectively connected to the inlets of the first-effect condensate tank 26, the second-effect condensate tank 23 and the third-effect condensate tank 20 through the product condensate pipe G18, the outlets of the first-effect condensate tank 26, the second-effect condensate tank 23 and the third-effect condensate tank 20 are connected to the inlet of the product condensate pump B12 through the product condensate pipe G18, the outlet of the product condensate pump B12 is connected to the hot side inlet of the product condensate preheater 16, and the hot side outlet of the product condensate preheater 16 is connected to the third-effect crystallization flushing pipe G19.

[0054] The upper overflow port of the secondary sedimentation tank 34 is connected to the inlet of the clear liquid effluent pump B15 through the sedimentation overflow pipe G33, the outlet of the clear liquid effluent pump B15 is connected to the cold side inlet of the single-effect condensate preheater 35, the cold side outlet of the single-effect condensate preheater 35 is connected to the outlet pipe of the single-effect circulation pump B16, and then they are connected together to the circulating liquid inlet of the single-effect crystallizer 37; the circulating liquid outlet of the single-effect crystallizer 37 is connected to the upper inlet of the tube side of the single-effect forced evaporator 36, the lower outlet of the tube side of the single-effect forced evaporator 36 is connected to the inlet of the single-effect circulation pump B16 through the single-effect circulation pipe G38, and the outlet of the single-effect circulation pump B16 is connected to the circulating liquid inlet of the single-effect crystallizer 37 through the single-effect circulation pipe G38.

[0055] The slurry outlet of the single-effect crystallizer 37 is connected to the inlet of the impure salt slurry pump B18 through the single-effect slurry pipe G43, and the outlet of the impure salt slurry pump B18 is connected to the inlet of the impure salt thickening tank 41. The bottom flow outlet of the impure salt thickening tank 41 is connected to the inlet of the impure salt centrifuge 42 through the single-effect thickening discharge pipe G44, and the solid phase outlet of the impure salt centrifuge 42 is connected to the impure salt outlet pipe G45. The liquid phase outlet of the impure salt centrifuge 42 is connected to the inlet of the drum dryer 43 through the mother liquor drying pipe G46, and the outlet of the drum dryer 43 is connected to the dry impure salt outlet pipe G47.

[0056] The secondary steam outlet of the single-effect crystallizer 37 is connected to the suction port of the steam jet pump 39, the main power port of the steam jet pump 39 is connected to the raw steam supplement pipe G42, the outlet of the steam jet pump 39 is connected to the shell-side steam inlet of the single-effect forced evaporator 36 through the single-effect secondary steam circulation pipe G41, and the shell-side condensate outlet of the single-effect forced evaporator 36 is connected to the inlet of the single-effect condensate tank 38 through the single-effect condensate pipe G39. The outlet of the single-effect condensate tank 38 is connected to the inlet of the single-effect condensate pump B17 through the single-effect condensate pipe G39, and the outlet of the single-effect condensate pump B17 is connected to the hot side inlet of the single-effect condensate preheater 35. The hot side outlet of the single-effect condensate preheater 35 flushes the TVR device area with materials through the single-effect flushing pipe G40.

[0057] The top exhaust port of the triple-effect separator 19 is connected to the secondary steam inlet of the scrubbing tower 28 through the terminal secondary steam delivery pipe G24, the secondary steam outlet of the scrubbing tower 28 is connected to the inlet of the steam compressor 29 through the terminal secondary steam delivery pipe G24, and the outlet of the steam compressor 29 is connected to the shell side steam inlet of the single-effect forced evaporator 24 through the secondary steam circulation pipe G25.

[0058] The secondary steam outlet of the first-effect crystallizer 25 is transported to the secondary steam inlet of the second-effect forced evaporator 21 through the first-effect to second-effect secondary steam pipe G26; similarly, the secondary steam outlet of the second-effect separator 22 is transported to the secondary steam inlet of the third-effect forced evaporator 18 through the second-effect to third-effect secondary steam pipe G27.

[0059] The non-condensable gas outlet of the single-effect forced evaporator 36 is connected to the hot side inlet of the single-effect surface cooler 40 through the single-effect non-condensable gas pipe G48, the hot side outlet of the single-effect surface cooler 40 is connected to the inlet of the single-effect vacuum pump B19, and the outlet of the single-effect vacuum pump B19 is connected to the single-effect non-condensable gas exhaust pipe G49, which discharges the non-condensable gas directly into the atmosphere.

[0060] The inlet material pipeline of the single-effect circulation pump B16 and the bottom outlet of the mother liquid tank 33 are connected to the inlet of the mother liquid reflux pump B14 through the mother liquid collection pipe G36. The outlet of the mother liquid reflux pump B14 is also connected to the accident pool inlet and the pipe reflux port of the first-effect forced evaporator 24 through the material emergency discharge pipe G11.

[0061] The pretreated ammonium sulfate wastewater is preheated by non-condensable gas and condensed water in two stages and then enters the three-effect heater for evaporation and crystallization. When the solid-liquid ratio of ammonium sulfate at the bottom of the cone of the first-effect crystallizer 25 reaches about 20%, the crystal slurry material is output.

[0062] The ammonium sulfate slurry material is pumped from the product slurry pipe G28 to the product thickening tank 30 through the product slurry pump B13 for thickening. When the particle size of the ammonium sulfate crystals at the bottom of the thickening tank exceeds 0.5 mm, they enter the product centrifuge 31 for solid-liquid separation. The separated viscous ammonium sulfate crystal salt enters the vibrating fluidized bed 32, and the dry qualified ammonium sulfate product is output.

[0063] The materials in the first-effect crystallizer 25, the second-effect separator 22 and the third-effect separator 19 that are not transported to the next stage can be returned to the forced evaporator through the forced circulation pump for circulation heat exchange, and evaporated and concentrated in the separator or crystallizer, effectively avoiding the adhesion and scaling of the materials in the forced evaporator tubes to affect the heat exchange efficiency.

[0064] The dilute ammonium sulfate material at the top of the product thickening tank 30 enters the secondary sedimentation tank 34 from the side through the thickening overflow pipe G32 for precipitation, and the heavy phase material settles to the bottom in the sedimentation tank and enters the mother liquor tank 33 through the sedimentation mother liquor pipe G34; the clear liquid rich in soluble phosphates at the top of the secondary sedimentation tank 34 enters the single-effect condensate preheater 35 through the sedimentation overflow pipe G33 and the clear liquid discharge pump B15 for preheating, and the preheated material enters the single-effect circulation pipe G38, and is added to the circulating crystallization process of the feed liquid to effectively remove the soluble impurities in the solution.

[0065] The phosphate-rich material is heated by the single-effect forced evaporator 36 and then enters the single-effect crystallizer 37 for evaporation and crystallization. When the solid-liquid ratio of the material at the bottom of the cone of the single-effect crystallizer 37 reaches about 16%, it is sent to the mixed salt thickening tank 41 through the single-effect slurry pipe G43 and the mixed salt slurry pump B18. The thickened material enters the mixed salt centrifuge 42 through the single-effect thickening discharge pipe G44 for solid-liquid separation. The solid phase mixed salt in the mixed salt centrifuge 42 is packaged and transported out through the mixed salt outlet pipe G45, and the mixed salt is initially separated.

[0066] A trench is set up in the device area of ​​the system for separating ammonium sulfate and miscellaneous salts from sulfuric acid wastewater, and the trench is sealed and discharged to the accident pool to avoid leakage of dangerous sulfuric acid in the wastewater, to ensure that toxic materials will not flow out once a leak occurs in the system, to ensure that the environment around the device area is not polluted and to ensure the personal safety of operators.

[0067] The above description is only the preferred feasible embodiment of the utility model, which shows and describes the basic principle, main features and advantages of the utility model, but does not limit the scope of patent protection of the utility model. The technicians in this industry should understand that the utility model is not limited by the above embodiments. In addition to the above embodiments, the utility model can also have other implementation modes without departing from the spirit and scope of the utility model. The utility model will also have various changes and improvements. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the utility model. The scope of protection required by the utility model is defined by the attached claims and their equivalents. The technical features not described in the utility model can be achieved by or using existing technologies, which will not be repeated here.

Claims

1. A system for evaporating, concentrating and salting ammonium sulfate wastewater containing sulfuric acid, comprising a triple-effect separator (19), a secondary-effect separator (22) and a primary-effect crystallizer (25), characterized in that: The circulation outlet of the triple-effect separator (19) is connected to the inlet of the triple-effect circulation pump (B7) through the triple-effect material circulation pipe (G13), and the outlet of the triple-effect circulation pump (B7) is connected to the circulation inlet of the triple-effect separator (19) through the triple-effect forced evaporator (18); The circulation outlet of the second-effect separator (22) is connected to the inlet of the second-effect circulation pump (B8) through the second-effect material circulation pipe (G15), and the outlet of the second-effect circulation pump (B8) is connected to the circulation inlet of the second-effect separator (22) through the second-effect forced evaporator (21); The circulation outlet of the first-effect crystallizer (25) is connected to the inlet of the first-effect circulation pump (B9) through the first-effect material circulation pipe (G17), and the outlet of the first-effect circulation pump (B9) is connected to the circulation inlet of the first-effect crystallizer (25) through the first-effect forced evaporator (24); The outlet of the ammonium sulfate wastewater pipe (G3) is connected to the cold side inlet of the product condensate preheater (16), the cold side outlet of the product condensate preheater (16) is connected to the cold side inlet of the product non-condensable gas preheater (17), the cold side outlet of the product non-condensable gas preheater (17) is connected to the three-effect material circulation pipe (G13), the outlet of the three-effect forced evaporator (18) is connected to the two-effect material circulation pipe (G15) through the three-effect to two-effect transfer pipe (G14); the outlet of the two-effect forced evaporator (21) is connected to the first-effect material circulation pipe (G17) through the second-effect to first-effect transfer pipe (G16); the product slurry outlet of the first-effect crystallizer (25) is connected to the mother liquor drying unit through the product slurry pipe (G28).

2. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 1, characterized in that: The top gas outlet of the triple-effect separator (19) is connected to the inlet of the scrubbing tower (28), the outlet of the scrubbing tower (28) is connected to the inlet of the steam compressor (29), the outlet of the steam compressor (29) is connected to the upper shell inlet of the first-effect forced evaporator (24) through the secondary steam circulation pipe (G25), the top gas outlet of the first-effect crystallizer (25) is connected to the upper shell inlet of the second-effect forced evaporator (21), and the top gas outlet of the second-effect separator (22) is connected to the upper shell inlet of the triple-effect forced evaporator (18).

3. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 2, characterized in that: The lower shell outlet of the first-effect forced evaporator (24) is connected to the first-effect condensate tank (26), the lower shell outlet of the second-effect forced evaporator (21) is connected to the second-effect condensate tank (23), the lower shell outlet of the third-effect forced evaporator (18) is connected to the third-effect condensate tank (20), the outlets of the first-effect condensate tank (26), the second-effect condensate tank (23) and the third-effect condensate tank (20) are all connected to the inlet of the product condensate pump (B12), the outlet of the product condensate pump (B12) is connected to the hot side inlet of the product condensate preheater (16), and the hot side outlet of the product condensate preheater (16) is connected to the third-effect crystallization flushing pipe (G19).

4. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 2, characterized in that: The shell-side non-condensable gas outlets of the first-effect forced evaporator (24), the second-effect forced evaporator (21), and the third-effect forced evaporator (18) are all connected to the hot side inlet of the product non-condensable gas preheater (17) through the product non-condensable gas pipe (G20), the hot side outlet of the product non-condensable gas preheater (17) is connected to the hot side inlet of the product surface cooler (27), the hot side outlet of the product surface cooler (27) is connected to the product vacuum pump (B11), the cooling water replenishment pipe (G22) is connected to the cold side inlet of the product surface cooler (27), and the cold side outlet of the product surface cooler (27) is connected to the circulation pipe of the scrubbing tower (28).

5. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 1, characterized in that: In the mother liquor drying unit: the outlet of the product slurry pipe (G28) is connected to the product thickening tank (30), the bottom flow outlet of the product thickening tank (30) is connected to the inlet of the product centrifuge (31), the solid phase outlet of the product centrifuge (31) is connected to the inlet of the vibrating fluidized bed (32), and the outlet of the vibrating fluidized bed (32) is connected to the dry product external transmission pipe (G31).

6. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 5, characterized in that: The overflow outlet of the product thickening tank (30) is connected to the secondary sedimentation tank (34), the underflow outlet of the secondary sedimentation tank (34) and the liquid phase outlet of the product centrifuge (31) are respectively connected to the mother liquid tank (33), and the outlet of the mother liquid tank (33) is connected to the tube side reflux port of the first-effect forced evaporator (24) through a mother liquid reflux pump (B14); the outlet of the mother liquid reflux pump (B14) is connected to the accident pool through a material emergency discharge pipe (G11).

7. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 6, characterized in that: The overflow outlet of the secondary precipitation tank (34) is connected to the cold side inlet of the single-effect condensate preheater (35) through a clear liquid effluent pump (B15), the cold side outlet of the single-effect condensate preheater (35) is connected to a single-effect circulation pipe (G38), the outlet of the single-effect circulation pipe (G38) is connected to the circulation inlet of the single-effect crystallizer (37), the circulation outlet of the single-effect crystallizer (37) is connected to the tube side inlet of the single-effect forced evaporator (36), the tube side outlet of the single-effect forced evaporator (36) is connected to the inlet of a single-effect circulation pump (B16), and the outlet of the single-effect circulation pump (B16) is connected to the single-effect circulation pipe (G38).

8. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 7, characterized in that: The impure salt slurry outlet of the single-effect crystallizer (37) is connected to the impure salt thickening tank (41) through the impure salt slurry pump (B18), the bottom flow outlet of the impure salt thickening tank (41) is connected to the inlet of the impure salt centrifuge (42), and the solid phase outlet of the impure salt centrifuge (42) is connected to the impure salt outlet pipe (G45).

9. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 8, characterized in that: The liquid phase outlet of the impure salt centrifuge (42) is connected to the inlet of the drum dryer (43), and the outlet of the drum dryer (43) is connected to the dry impure salt outlet pipe (G47).

10. The evaporation, concentration and salt separation system for ammonium sulfate wastewater containing sulfuric acid according to claim 8, characterized in that: The top air outlet of the single-effect crystallizer (37) is connected to the injection port of the steam jet pump (39), the main inlet of the steam jet pump (39) is connected to the raw steam replenishment pipe (G42), the outlet of the steam jet pump (39) is connected to the shell side inlet of the single-effect forced evaporator (36), the shell side outlet of the single-effect forced evaporator (36) is connected to the single-effect condensate tank (38), the outlet of the single-effect condensate tank (38) is connected to the hot side inlet of the single-effect condensate preheater (35) through the single-effect condensate pump (B17), and the hot side outlet of the single-effect condensate preheater (35) is connected to the single-effect flushing pipe (G40).

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