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CN-224212436-U - Evaporation crystallization salt separation treatment system for ammonium sulfate and monoammonium phosphate mixed solution

CN224212436UCN 224212436 UCN224212436 UCN 224212436UCN-224212436-U

Abstract

The utility model discloses an ammonium sulfate and monoammonium phosphate mixed solution evaporation crystallization salt separation treatment system which comprises a preheating unit, an ammonium sulfate evaporation concentration unit, an ammonium sulfate evaporation crystallization unit, a recovery heat exchange unit, an ammonium sulfate post-treatment unit, a monoammonium phosphate cooling crystallization unit, a monoammonium phosphate post-treatment unit and a salt impurity treatment unit. The technical scheme adopted by the utility model aims at carrying out combination treatment on the mixed solution containing ammonium sulfate and monoammonium phosphate, so that qualified ammonium sulfate crystal salt, monoammonium phosphate crystal salt and mixed salt can be obtained, and the byproduct benefit of a wastewater treatment system can be effectively improved.

Inventors

  • WANG XU
  • HAN XIAOTAO

Assignees

  • 湖北博睿鑫科技有限公司

Dates

Publication Date
20260508
Application Date
20250331

Claims (10)

  1. 1. An evaporative crystallization salt separation treatment system for a mixed solution of ammonium sulfate and monoammonium phosphate, which is characterized by comprising the following components: A preheating unit (1) for carrying out preheating treatment on raw water containing a mixed solution of ammonium sulfate and monoammonium phosphate; The ammonium sulfate evaporation concentration unit (2) is used for carrying out evaporation concentration treatment on raw water to obtain concentrated solution, and the TDS value of the concentrated solution is 450mg/L-500mg/L; The ammonium sulfate evaporation crystallization unit (3) is used for performing evaporation crystallization treatment on the concentrated solution to obtain concentrated salt slurry, wherein the solid content of the concentrated salt slurry is 5% -15%; The recovery heat exchange unit (4) is used for pressurizing and heating the steam discharged by the ammonium sulfate evaporation concentration unit (2) and the ammonium sulfate evaporation crystallization unit (3), and conveying the steam subjected to the pressurizing and heating treatment to the ammonium sulfate evaporation concentration unit (2) and the ammonium sulfate evaporation crystallization unit (3); The system comprises an ammonium sulfate post-treatment unit (5) for carrying out centrifugal treatment on concentrated salt slurry to obtain ammonium sulfate and ammonium sulfate mother liquor, wherein an ammonium sulfate mother liquor reflux pipe is arranged between the ammonium sulfate post-treatment unit (5) and the ammonium sulfate evaporation crystallization unit (3) and is used for refluxing the ammonium sulfate mother liquor to the ammonium sulfate evaporation crystallization unit (3); A monoammonium phosphate cooling crystallization unit (6) for cooling and crystallizing the ammonium sulfate mother liquor to obtain salt slurry; The system comprises a monoammonium phosphate post-treatment unit (7) for carrying out centrifugal treatment on salt slurry to obtain monoammonium phosphate and monoammonium phosphate mother liquor, wherein a monoammonium phosphate mother liquor reflux pipe is arranged between the monoammonium phosphate post-treatment unit (7) and a monoammonium phosphate cooling crystallization unit (6), and the monoammonium phosphate mother liquor reflux pipe is used for refluxing the monoammonium phosphate mother liquor to the monoammonium phosphate cooling crystallization unit (6); and the mixed salt treatment unit (8) is used for drying the ammonium phosphate mother liquor conveyed by the monoammonium phosphate post-treatment unit (7) to obtain mixed salt.
  2. 2. The evaporation, crystallization and salt separation treatment system for mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the preheating unit (1) comprises a feeding box (11), a feed pump (12), a distilled water preheater (13) and a steam preheater (14) which are sequentially connected, the feeding box (11) is used for storing raw water, the distilled water preheater (13) is provided with a first heat exchange cavity, the first heat exchange cavity is used for inputting distilled water to perform primary preheating on the raw water, and the steam preheater (14) is provided with a second heat exchange cavity, and the second heat exchange cavity is used for inputting steam to perform secondary preheating on the raw water.
  3. 3. The system for evaporating, crystallizing and salt separating treatment of mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 2, wherein the distilled water preheater (13) and the steam preheater (14) are both plate heat exchangers.
  4. 4. The system for evaporating, crystallizing and separating salt from mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the ammonium sulfate evaporating and concentrating unit (2) comprises a falling film evaporator (21), a falling film circulating pump (22), a falling film separator (23) and a falling film transfer pump (24), the falling film circulating pump (22) is used for carrying out circulating treatment on raw water of the falling film evaporator (21) to obtain concentrated liquor in the falling film evaporator (21), the falling film separator (23) is used for carrying out gas separation on gas generated by the falling film evaporator (21), the separated liquid is returned to the falling film evaporator (21), the separated steam is conveyed to the recovery heat exchange unit (4), and the falling film transfer pump (24) is used for conveying the concentrated liquor to the ammonium sulfate post-treatment unit (5).
  5. 5. The system for evaporating, crystallizing and separating salt of mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the ammonium sulfate evaporating and crystallizing unit (3) comprises a forced circulation crystallizing separator (31), a forced circulation evaporator (32), a forced circulation pump (33) and an ammonium sulfate discharging pump (34), the forced circulation crystallizing separator (31) and the forced circulation evaporator (32) are communicated through the forced circulation pump (33), the forced circulation pump (33) is used for carrying out circulation treatment on concentrated liquor of the forced circulation crystallizing separator (31), so that the concentrated liquor forms ammonium sulfate crystals in the forced circulation evaporator (32) and returns the ammonium sulfate crystals to the forced circulation crystallizing separator (31) to obtain concentrated salt slurry, steam generated by the forced circulation crystallizing separator (31) is used for being conveyed to the recovery heat exchange unit (4), and the ammonium sulfate discharging pump (34) is used for conveying the concentrated salt slurry to the ammonium sulfate post-treatment unit (5).
  6. 6. The system for evaporating, crystallizing and salt separating mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 2, wherein the recovery heat exchange unit (4) comprises a compressor (41), a gas washing tower (42), a condensate water tank (43) and a condensate water pump (44), the gas washing tower (42) is used for receiving steam discharged by the ammonium sulfate evaporating, concentrating unit (2) and the ammonium sulfate evaporating, crystallizing unit (3), the compressor (41) is used for pressurizing and heating gas conveyed by the gas washing tower (42) and conveying the pressurized and heated steam into the ammonium sulfate evaporating, concentrating unit (2) and the ammonium sulfate evaporating, crystallizing unit (3), the condensate water tank (43) is used for receiving condensate water discharged by the ammonium sulfate evaporating, concentrating unit (2) and the ammonium sulfate evaporating, crystallizing unit (3), and the condensate water pump (44) is used for conveying condensate water of the condensate water tank (43) into a first heat exchange cavity of the distilled water heater (13).
  7. 7. The system for evaporating, crystallizing and separating salt of mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the ammonium sulfate post-treatment unit (5) comprises an ammonium sulfate thickener (51), an ammonium sulfate centrifuge (52), an ammonium sulfate mother liquor tank (53) and an ammonium sulfate mother liquor pump (54), the ammonium sulfate thickener (51), the ammonium sulfate centrifuge (52) and the ammonium sulfate mother liquor tank (53) are sequentially communicated, the ammonium sulfate centrifuge (52) is used for carrying out centrifugal treatment on concentrated salt slurry and obtaining ammonium sulfate and ammonium sulfate mother liquor, the ammonium sulfate mother liquor tank (53) is used for storing ammonium sulfate mother liquor, the input end of the ammonium sulfate mother liquor pump (54) is communicated with the ammonium sulfate mother liquor tank (53), one output end of the ammonium sulfate mother liquor pump (54) is communicated with the ammonium sulfate evaporating and crystallizing unit (3) through an ammonium sulfate mother liquor return pipe, and the other output end of the ammonium sulfate mother liquor pump (54) is communicated with the monoammonium phosphate cooling and crystallizing unit (6).
  8. 8. The evaporation, crystallization and salt separation system for mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the monoammonium phosphate cooling and crystallizing unit (6) comprises a low-temperature flash evaporation crystallizer (61), a flash evaporation circulating pump (62), a steam condenser (63), a vacuum pump (64) and an ammonium phosphate discharging pump (65), the vacuum pump (64) is used for pumping negative pressure to the low-temperature flash evaporation crystallizer (61) so as to enable ammonium sulfate mother liquor in the low-temperature flash evaporation crystallizer (61) to be subjected to flash evaporation crystallization under the negative pressure condition to obtain salt slurry, the flash evaporation circulating pump (62) is used for circulating the ammonium sulfate mother liquor in the low-temperature flash evaporation crystallizer (61) so as to enable the ammonium sulfate mother liquor to be subjected to flash evaporation cooling, the steam condenser (63) is used for cooling steam generated by the low-temperature flash evaporation crystallizer (61), and the ammonium phosphate discharging pump (65) is used for conveying the salt slurry in the low-temperature flash evaporation crystallizer (61) to the monoammonium phosphate aftertreatment unit (7).
  9. 9. The evaporation, crystallization and salt separation treatment system for mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the monoammonium phosphate after-treatment unit (7) comprises a monoammonium phosphate thickener (71), an ammonium phosphate centrifugal machine (72), an ammonium phosphate mother liquor tank (73) and an ammonium phosphate mother liquor pump (74), the ammonium phosphate thickener (71), the ammonium phosphate centrifugal machine (72) and the ammonium phosphate mother liquor tank (73) are sequentially communicated, the ammonium phosphate centrifugal machine (72) is used for carrying out centrifugal treatment on salt slurry to obtain monoammonium phosphate and ammonium phosphate mother liquor, the ammonium phosphate mother liquor tank (73) is used for storing the ammonium phosphate mother liquor, the input end of the ammonium phosphate mother liquor pump (74) is communicated with the ammonium phosphate mother liquor tank (73), one output end of the ammonium phosphate mother liquor pump (74) is communicated with the monoammonium phosphate cooling and crystallizing unit (6) through an ammonium phosphate mother liquor backflow pipe, and the other output end of the ammonium phosphate mother liquor pump (74) is communicated with the mixed salt treatment unit (8).
  10. 10. The system for evaporating, crystallizing and separating salt from mixed liquor of ammonium sulfate and monoammonium phosphate according to claim 1, wherein the salt impurity treatment unit (8) comprises a mother liquor drier (81), the mother liquor drier (81) is a scraper drum drier or a rake drier, and the mother liquor drier (81) is used for drying ammonium phosphate mother liquor and outputting salt impurities.

Description

Evaporation crystallization salt separation treatment system for ammonium sulfate and monoammonium phosphate mixed solution Technical Field The utility model belongs to the technical field of high-salt wastewater evaporation and salt separation treatment, and particularly relates to an ammonium sulfate and monoammonium phosphate mixed solution evaporation, crystallization and salt separation treatment system. Background The production process of the lithium iron phosphate battery can be simplified to produce ferric phosphate firstly, then the ferric phosphate is sintered with lithium carbonate, glucose and the like to produce lithium iron phosphate, a large amount of wastewater can be produced in the production process of the ferric phosphate, the production process of the ferric phosphate can be roughly divided into an ammonia method and a sodium method according to different used raw materials, the main difference is that ammonia water is used in the ammonia process of the ferric phosphate, sodium hydroxide is used in the sodium process of the ferric phosphate, and various ferric phosphate manufacturers tend to produce ammonia process with lower production cost due to the aggravation of the competition of the ferric phosphate industry in recent years. The ammonia ferric phosphate production process can produce mother liquor and washing water containing ammonium sulfate, wherein the mother liquor and washing water contain a small amount of monoammonium phosphate, and the ammonium sulfate byproducts are sold, the produced distilled water is recycled and the mixed salt is sent out after the pretreatment and the membrane concentration are carried out in an evaporation crystallization system. At present, the process mainly adopted for treating the ammonium iron phosphate wastewater is pretreatment, reverse osmosis and evaporative crystallization, and the general reverse osmosis process can concentrate the TDS (total dissolved solids) of the wastewater to about 15 percent, and the wastewater is removed from an evaporative crystallization system. The conventional evaporative crystallization system is used for evaporating and crystallizing the ammonium sulfate byproducts, but the monoammonium phosphate can be separated from the salt, so that when the content of phosphate radical in the wastewater is increased, the quality of the ammonium sulfate byproducts cannot meet the outsourcing standard, the quantity of the mixed salt is increased, the byproduct benefits of ferric phosphate manufacturers are reduced, and the method is relatively unacceptable in the current economic environment. Therefore, the process for realizing evaporation, crystallization and salt separation of ammonium sulfate and monoammonium phosphate is a problem to be solved in the prior art. Disclosure of utility model The utility model aims to provide an evaporation crystallization salt separation treatment system for mixed liquor of ammonium sulfate and monoammonium phosphate, which is used for solving the problems in the prior art. In order to achieve the purpose, the utility model adopts the following technical scheme that the evaporation crystallization salt separation treatment system for the mixed solution of ammonium sulfate and monoammonium phosphate comprises: A preheating unit for preheating raw water containing a mixed solution of ammonium sulfate and monoammonium phosphate; The ammonium sulfate evaporation concentration unit is used for carrying out evaporation concentration treatment on raw water to obtain concentrated solution, and the TDS value of the concentrated solution is 450mg/L-500mg/L; the ammonium sulfate evaporation crystallization unit is used for performing evaporation crystallization treatment on the concentrated solution to obtain concentrated salt slurry, wherein the solid content of the concentrated salt slurry is 5% -15%; The recovery heat exchange unit is used for pressurizing and heating the steam discharged by the ammonium sulfate evaporation concentration unit and the ammonium sulfate evaporation crystallization unit, and conveying the pressurized and heated steam to the ammonium sulfate evaporation concentration unit and the ammonium sulfate evaporation crystallization unit; The system comprises an ammonium sulfate post-treatment unit, an ammonium sulfate evaporation crystallization unit, an ammonium sulfate mother liquor recycling pipe, an ammonium sulfate evaporation crystallization unit and an ammonium sulfate concentration unit, wherein the ammonium sulfate post-treatment unit is used for carrying out centrifugal treatment on concentrated salt slurry to obtain ammonium sulfate and ammonium sulfate mother liquor; the monoammonium phosphate cooling crystallization unit is used for performing cooling crystallization treatment on the ammonium sulfate mother liquor to obtain salt slurry; The system comprises a monoammonium phosphate post-treatment unit, a monoammonium phosphate cooling crystallization unit and a