Ammonium sulfate wastewater treatment system and method

Abstract

The invention discloses an ammonium sulfate wastewater treatment system and method, and the system comprises an ammonium sulfate wastewater storage pool which is used for collecting ammonium sulfate wastewater; the calcium hydroxide preparation system is used for preparing a calcium hydroxide solution, an evaporator and a first circulating heater and is used for reacting ammonium sulfate wastewater and calcium hydroxide and heating and evaporating; the first crystallizer and the second circulating heater as well as the second crystallizer and the third circulating heater are used for two times of evaporative crystallization, a final concentrated solution is filtered by the filter and then flows into the mother liquor collecting tank to facilitate wastewater treatment, and evaporated ammonia gas is absorbed by the cooling absorption tower and the condensate collecting tank to form ammonia water; and condensate water of the second heat exchanger, the first circulating heater, the second circulating heater and the third circulating heater also flows back to the condensate collecting pool. According to the wastewater treatment system and method, the ammonium sulfate wastewater and the calcium hydroxide solution are distilled and crystallized, so that calcium sulfate and ammonia water can be recovered, and waste utilization is realized.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to an ammonium sulfate wastewater treatment system and a method thereof. Background Art

[0002] When ammonium sulfate is produced and used industrially, a large amount of ammonium sulfate wastewater will be generated, and ammonium sulfate wastewater is likely to cause water environment deterioration. Therefore, the discharge of ammonium sulfate wastewater is strictly restricted. Therefore, how to treat ammonium sulfate wastewater is a technical problem that technicians in this field need to solve urgently. At present, ammonium sulfate wastewater is generally directly mixed with other wastewaters, and then treated by activated sludge method or biochemical method, but this will cause the ammonia nitrogen in the wastewater to exceed the standard, thereby increasing the difficulty of sewage treatment. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an ammonium sulfate wastewater treatment system, which distills and crystallizes ammonium sulfate wastewater and calcium hydroxide solution, so as to recover calcium sulfate and ammonia water, thereby realizing waste utilization.

[0004] In addition, another technical problem to be solved by the present invention is to provide a method for treating ammonium sulfate wastewater, which uses the above-mentioned ammonium sulfate wastewater treatment system to recover calcium sulfate and ammonia water, thereby realizing waste utilization.

[0005] In order to solve the above technical problems, the technical solution of the present invention is: an ammonium sulfate wastewater treatment system, comprising

[0006] An ammonium sulfate wastewater storage tank is used to collect the ammonium sulfate wastewater storage tank, the ammonium sulfate wastewater storage tank is connected to the wastewater inlet of the first heat exchanger through a first wastewater delivery pipeline, the wastewater outlet of the first heat exchanger is connected to the wastewater inlet of the second heat exchanger, the wastewater outlet on the second heat exchanger is connected to the wastewater inlet of the evaporator through a first liquid inlet pipeline, and the second heat exchanger is also provided with a steam inlet, a steam outlet and a condensed water outlet; the bottom of the evaporator is provided with a first bottom circulation pipeline, the first bottom circulation pipeline is connected to the bottom of the tube side of the first circulation heater, the top of the evaporator is provided to be connected to the steam inlet of the second heat exchanger through a steam recycling pipeline, and the steam outlet of the second heat exchanger is connected to the steam reflux main pipe; the top of the tube side of the first circulation heater is connected to the top of the evaporator through the first top circulation pipeline, and the shell side inlet of the first circulation heater is connected to the steam supply system; the shell side outlet of the first circulation heater is connected to the steam reflux main pipe;

[0007] A first crystallizer and a second circulation heater, wherein the bottom of the first crystallizer is connected to the bottom tube side of the second circulation heater through a second bottom circulation pipeline, the concentrated liquid outlet on the evaporator is connected to the second bottom circulation pipeline through a first concentrated liquid outflow pipeline, the tube side top of the second circulation heater is connected to the top of the first crystallizer through a second top circulation pipeline, the shell side inlet of the second circulation heater is connected to a steam supply system; and the shell side outlet of the second circulation heater is connected to a steam reflux main pipe;

[0008] A second crystallizer and a third circulation heater, the bottom of the second crystallizer is connected to the bottom tube side of the third circulation heater through a third bottom circulation pipeline, the concentrated liquid outlet of the first crystallizer is connected to the third bottom circulation pipeline through a second concentrated liquid outflow pipe, the tube side top of the third circulation heater is connected to the top of the second crystallizer through a third top circulation pipeline, the shell side inlet of the third circulation heater is connected to the steam outlet at the top of the first crystallizer; the shell side outlet of the third circulation heater and the top steam outlet of the second crystallizer are both connected to the steam reflux main pipe; the steam reflux main pipe is connected to the steam inlet of the first heat exchanger, and the gas outlet of the first heat exchanger is connected to the negative pressure system; the third bottom circulation pipeline is connected to a concentrated liquid drain pipe, and the concentrated liquid drain pipe is connected to a filter and a mother liquor collection tank;

[0009] A cooling absorption tower and a condensate collection pool, wherein the steam reflux main pipe is connected to the cooling absorption tower, the bottom of the cooling absorption tower is connected to the condensate collection pool via a condensate outlet pipe, and the condensate collection pool is connected to the top spray port of the cooling absorption tower via a condensate circulation pipeline;

[0010] The condensate outlet of the second heat exchanger is connected to the liquid inlet of the third circulation heater through the condensate outlet pipe, the liquid outlet of the first circulation heater is connected to the liquid inlet of the second circulation heater through the first liquid outlet pipe, the liquid outlet of the second circulation heater is connected to the liquid inlet of the third circulation heater through the second liquid outlet pipe, and the liquid outlet of the third circulation heater is connected to the cooling tank through the third liquid outlet pipe;

[0011] The calcium hydroxide configuration system is used for configuring the calcium hydroxide solution, and the calcium hydroxide configuration system is respectively connected to the evaporator, the first crystallizer and the second crystallizer.

[0012] Preferably, the treatment system also includes a third heat exchanger, the wastewater inlet of the third heat exchanger is connected to the wastewater outlet of the first heat exchanger, the wastewater outlet of the third heat exchanger is connected to the wastewater inlet of the second heat exchanger, and the liquid inlet and liquid outlet of the third heat exchanger are connected to the third liquid outlet pipe. Therefore, the third heat exchanger can fully utilize the heat energy in the condensate, further enhance the heat exchange of ammonium sulfate wastewater, and improve the utilization efficiency of heat energy.

[0013] Preferably, the wastewater outlet on the second heat exchanger is connected to the top of the first crystallizer through a second liquid inlet pipeline. Therefore, part of the wastewater after heat exchange in the second heat exchanger can also enter the first crystallizer and be evaporated and crystallized in the first crystallizer, thereby improving the efficiency of evaporation and crystallization.

[0014] Preferably, the top of the evaporator is also connected to the shell side inlet of the first circulation heater through a steam recycling pipeline, so that the energy in the steam evaporated by the evaporator is reused to further improve the energy utilization rate.

[0015] Preferably, the calcium hydroxide configuration system includes a calcium hydroxide preparation tank, a stirring device is provided in the calcium hydroxide preparation tank, an outlet of the calcium hydroxide preparation tank is communicated with a calcium hydroxide solution storage tank through a calcium hydroxide delivery pipeline, an aeration device is provided in the calcium hydroxide solution storage tank, the calcium hydroxide solution storage tank is communicated with an evaporator, a first crystallizer and a second crystallizer respectively through a calcium hydroxide solution supply branch pipeline, a flow meter is provided on each calcium hydroxide solution supply branch pipeline, the calcium hydroxide is sent to the calcium hydroxide solution storage tank after being configured and stirred, aeration and stirring in the calcium hydroxide solution storage tank avoids precipitation, and then saturation can be easily and conveniently sent to the evaporator, the first crystallizer and the second crystallizer, and the flow rate entering can be accurately controlled by the flow meter to accurately control the pH value.

[0016] After adopting the above technical scheme, the effect of the present invention is as follows: in the treatment system, wastewater and calcium hydroxide solution enter the evaporator according to the ratio, and the evaporator and the first circulation heater are cyclically heated and evaporated, so that hot ammonia will be discharged, and the calcium sulfate obtained by the reaction will flow into the first crystallizer with the concentrated liquid, and the condensed water will flow into the condensate collection pool to be collected and used for cyclic absorption of ammonia to form ammonia water, and the concentrated liquid will be concentrated and crystallized again in the first crystallizer and the second crystallizer; and the P value during evaporation and crystallization is accurately controlled to facilitate the generation of ammonia, and finally the ammonia is absorbed by spraying to form ammonia water, which can be used for desulfurization and denitrification in power plants; and the calcium sulfate in the concentrated liquid can be used for the production of gypsum after filtering, and the liquid can enter the conventional sewage treatment system again, so that the ammonia in the ammonium sulfate is separated, the difficulty of subsequent sewage treatment is reduced, and the calcium sulfate and ammonia water can be recovered at the same time.

[0017] To solve the above second technical problem, the solution of the present invention is: a method for treating ammonium sulfate wastewater, which uses the above ammonium sulfate wastewater treatment system and comprises the following steps:

[0018] S1. Collecting sodium sulfate wastewater into an ammonium sulfate wastewater storage tank; the calcium hydroxide preparation system prepares calcium hydroxide solution;

[0019] S2, the ammonium sulfate wastewater is first subjected to a first heat exchange with the steam in the steam reflux main pipe in the first heat exchanger, and then enters the second heat exchanger to conduct a second heat exchange with the steam discharged from the top of the evaporator, and finally enters the evaporator quantitatively; the calcium hydroxide solution is quantitatively introduced into the evaporator to react with the ammonium sulfate wastewater, and the pH value in the evaporator is monitored to control the pH value between 9 and 10; the concentrated solution after the reaction is circulated between the tube side of the first circulation heater and the evaporator; a part of the steam evaporated from the evaporator enters the shell side of the second circulation heater, and the other part enters the second heat exchanger;

[0020] S3, the concentrated liquid after evaporation enters the circulating evaporation crystallization process between the first crystallizer and the second circulating heater through the second bottom circulating pipeline, the calcium hydroxide solution is added to the first crystallizer as needed to control the pH value to be between 9-10, and the shell side of the second circulating heater is also heated by the steam supply system; the concentrated liquid of the tube side of the second circulating heater is sent to the first crystallizer; the condensed liquid of the first circulating heater enters the second circulating heater through the first liquid outlet pipe;

[0021] S4, the steam at the top of the first crystallizer is supplied to the shell side of the third circulation heater; the concentrated liquid from the first crystallizer enters the circulating evaporation crystallization process between the second crystallizer and the third circulation heater through the third bottom circulation pipeline, and the calcium hydroxide solution is added to the second crystallizer as needed to control the pH value to be between 9 and 10; the condensed liquid from the second circulation heater enters the third circulation heater through the second liquid outlet pipe, and the condensed water from the second heat exchanger also enters the third circulation heater through the condensed water outlet pipe;

[0022] S5, the steam at the top of the second crystallizer, the steam of the first circulation heater, the second circulation heater and the third circulation heater are introduced into the steam reflux main pipe and finally enter the cooling absorption tower to be cooled and collected in the condensate collection pool; the concentrated liquid at the bottom of the second crystallizer is filtered by the filter and the liquid is collected in the mother liquid collection pool; the liquid outlet of the third circulation heater is connected to the cooling pool through the third liquid outlet pipe.

[0023] Preferably, the ammonium sulfate wastewater is subjected to enhanced heat exchange after the first heat exchange and before the second heat exchange. After the first heat exchange, the ammonium sulfate wastewater enters the third heat exchanger for enhanced heat exchange with the condensed water discharged from the third circulation heater; the cooling water after heat exchange in the third heat exchanger flows into the cooling pool; and the condensed water from the first heat exchanger also flows into the third heat exchanger.

[0024] After adopting the above technical scheme, the effect of the present invention is as follows: the treatment method uses the above treatment system to react ammonium sulfate wastewater with calcium hydroxide, and separates and recovers ammonia and calcium sulfate by heating evaporation and crystallization, and fully utilizes thermal energy while controlling the pH value of the evaporation and crystallization of the reaction, which is more conducive to the generation of ammonia and the crystallization and dehydration of calcium sulfate. The ammonia content in the concentrated liquid finally treated is low, so that the subsequent sewage treatment is not affected. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 It is a system diagram of a part of the system in the embodiment of the present invention;

[0027] Figure 2 is a system diagram of the remaining parts of the system in an embodiment of the present invention;

[0028] In the attached drawings: 1. calcium hydroxide preparation tank; 2. stirring device; 3. calcium hydroxide solution storage tank; 4. aeration device; 5. ammonium sulfate wastewater storage tank; 6. first wastewater delivery pipeline; 7. wastewater delivery pump; 8. first heat exchanger; 9. second heat exchanger; 10. first liquid inlet pipeline; 11. evaporator; 12. first bottom circulation pipeline; 13. first circulation heater; 14. first top circulation pipeline; 15. steam supply system; 16. steam recycling pipeline; 17. steam reflux main pipe; 18. second liquid inlet pipeline; 19. first crystallizer; 20. second circulation heater; 21. second bottom circulation pipeline; 22. first concentrated 1. The condensate outflow pipeline; 23. The second top circulation pipeline; 24. The second concentrated liquid outflow pipeline; 25. The third bottom circulation pipeline; 26. The third top circulation pipeline; 27. The vacuum pump; 28. The concentrated liquid discharge pipe; 29. ​​The filter; 30. The mother liquor collection tank; 31. The condensate collection tank; 32. The third heat exchanger; 33. The cooling absorption tower; 34. The condensate outlet pipe; 35. The first outlet pipe; 36. The second outlet pipe; 37. The third outlet pipe; 38. The wastewater flow meter; 39. The calcium hydroxide supply main; 40. The second crystallizer; 41. The third circulation heater; 42. The condensate outlet pipe; 43. The condensate circulation pipeline. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below through specific examples.

[0030] like Figure 1 and Figure 2 As shown, Figure 1 and Figure 2 An ammonium sulfate wastewater treatment system is shown.

[0031] Among them, because the system is relatively complex, the system is divided into Figure 1 and Figure 2 ,in Figure 1 and Figure 2 The same letters in the figure represent the same pipe, where a1 and a2, b1 and b2, c1 and c2, d1 and d21, e1 and e2, f1 and f2, g1 and g2, h1 and h2, i1 and i2 are the two ends cut off from a pipe respectively. The actual system is interconnected.

[0032] The ammonium sulfate wastewater storage tank 5 is used to collect the ammonium sulfate wastewater storage tank 5. The ammonium sulfate wastewater storage tank 5 is connected to the wastewater inlet of the first heat exchanger 8 through the first wastewater delivery pipeline 6. The first wastewater delivery pipeline 6 is provided with a wastewater flowmeter 38 and a wastewater delivery pump 7. The wastewater outlet of the first heat exchanger 8 is connected to the wastewater inlet of the second heat exchanger 9. The wastewater outlet on the second heat exchanger 9 is connected to the wastewater inlet of the evaporator 11 through the first liquid inlet pipeline 10. The second heat exchanger 9 is also provided with a steam inlet, a steam outlet and a condensed water outlet; the first heat exchanger 8 and the second heat exchanger 9 are currently conventional tube-type heat exchangers.

[0033] The bottom of the evaporator 11 is provided with a first bottom circulation pipeline 12, which is connected to the bottom of the tube side of the first circulation heater 13. The top of the evaporator 11 is connected to the steam inlet of the second heat exchanger 9 through a steam recycling pipeline 16, and the steam outlet of the second heat exchanger 9 is connected to the steam reflux main pipe 17; the top of the tube side of the first circulation heater 13 is connected to the top of the evaporator 11 through the first top circulation pipeline 14, and the shell side inlet of the first circulation heater 13 is connected to the steam supply system 15; the shell side outlet of the first circulation heater 13 is connected to the steam reflux main pipe 17;

[0034] A first crystallizer 19 and a second circulation heater 20, wherein the bottom of the first crystallizer 19 is connected to the bottom tube side of the second circulation heater 20 through a second bottom circulation pipeline 21, the concentrate outlet on the evaporator 11 is connected to the second bottom circulation pipeline 21 through a first concentrate outflow pipeline 22, the tube side top of the second circulation heater 20 is connected to the top of the first crystallizer 19 through a second top circulation pipeline 23, the shell side inlet of the second circulation heater 20 is connected to the steam supply system 15; the shell side outlet of the second circulation heater 20 is connected to the steam reflux main pipe 17;

[0035] A second crystallizer 40 and a third circulation heater 41, wherein the bottom of the second crystallizer 40 is connected to the bottom tube side of the third circulation heater 41 through a third bottom circulation pipeline 25, the concentrated liquid outlet of the first crystallizer 19 is connected to the third bottom circulation pipeline 25 through a second concentrated liquid outflow pipe 24, the tube side top of the third circulation heater 41 is connected to the top of the second crystallizer 40 through a third top circulation pipeline 26, and the shell side inlet of the third circulation heater 41 is connected to the steam outlet at the top of the first crystallizer 19; the shell side outlet of the third circulation heater 41 and the top steam outlet of the second crystallizer 40 are both connected to the steam reflux main pipe 17; the steam reflux main pipe 17 is connected to the steam inlet of the first heat exchanger 8, and the gas outlet of the first heat exchanger 8 is connected to the negative pressure system; the third bottom circulation pipeline 25 is connected to a concentrated liquid drain pipe 28, and the concentrated liquid drain pipe 28 is connected to a filter 29 and a mother liquor collection tank 30;

[0036] A cooling absorption tower 33 and a condensate collecting pool 31, the steam reflux main pipe 17 is connected to the cooling absorption tower 33, the bottom of the cooling absorption tower 33 is connected to the condensate collecting pool 31 through a condensate outlet pipe 42, and the condensate collecting pool 31 is connected to the top spray port of the cooling absorption tower 33 through a condensate circulation pipeline 43; the negative pressure system includes a vacuum pump 27, and a gas-liquid separator is also connected to the negative pressure absorption tower, the gas phase pipe port of the gas-liquid separator is connected to the vacuum pump 27, and the liquid phase pipe port is connected to the condensate outlet pipe 42.

[0037] The condensate outlet of the second heat exchanger 9 is connected to the liquid inlet of the third circulation heater through the condensate outlet pipe 34, the liquid outlet of the first circulation heater 13 is connected to the liquid inlet of the second circulation heater 20 through the first liquid outlet pipe 35, the liquid outlet of the second circulation heater 20 is connected to the liquid inlet of the third circulation heater 41 through the second liquid outlet pipe 36, and the liquid outlet of the third circulation heater 41 is connected to the cooling tank through the third liquid outlet pipe 37;

[0038] A calcium hydroxide configuration system is used to configure a calcium hydroxide solution, and the calcium hydroxide configuration system is respectively connected to an evaporator 11, a first crystallizer 19, and a second crystallizer 40. The calcium hydroxide configuration system includes a calcium hydroxide preparation tank 1, a stirring device 2 is provided in the calcium hydroxide preparation tank 1, the outlet of the calcium hydroxide preparation tank 1 is connected to a calcium hydroxide solution storage tank 3 through a calcium hydroxide delivery pipeline, an aeration device 4 is provided in the calcium hydroxide solution storage tank 3, the calcium hydroxide solution storage tank 3 is respectively connected to the evaporator 11, the first crystallizer 19, and the second crystallizer 40 through a calcium hydroxide supply main pipe 39 and a calcium hydroxide solution supply branch pipeline, and a flow meter is provided on each calcium hydroxide solution supply branch pipeline, the calcium hydroxide is sent to the calcium hydroxide solution storage tank 3 after being configured and stirred, aeration and stirring in the calcium hydroxide solution storage tank 3 avoids precipitation, and then saturation can be easily and conveniently sent to the evaporator 11, the first crystallizer 19, and the second crystallizer 40, and the flow rate entering can be accurately controlled by the flow meter to accurately control the pH value.

[0039] Among them, Figure 2 As shown, the treatment system also includes a third heat exchanger 32, the wastewater inlet of the third heat exchanger 32 is connected to the wastewater outlet of the first heat exchanger 8, the wastewater outlet of the third heat exchanger 32 is connected to the wastewater inlet of the second heat exchanger 9, and the liquid inlet and liquid outlet of the third heat exchanger 32 are connected to the third liquid outlet pipe 37. Therefore, the third heat exchanger 32 can fully utilize the heat energy in the condensate in the third liquid outlet pipe 37, further enhance the heat exchange of ammonium sulfate wastewater, and improve the utilization efficiency of thermal energy.

[0040] The wastewater outlet on the second heat exchanger 9 is connected to the top of the first crystallizer 19 through the second liquid inlet pipeline 18. In this way, a part of the ammonium sulfate wastewater can flow into the first crystallizer 19 after heat exchange in the second heat exchanger 9, thereby sharing the evaporation and crystallization pressure of the evaporator 11.

[0041] The top of the evaporator 11 is also connected to the shell side inlet of the first circulation heater 13 through the steam recycling pipeline 16, so that the energy in the steam evaporated by the evaporator 11 is reused to further improve the energy utilization rate.

[0042] In addition, the present invention also discloses a method for treating ammonium sulfate wastewater, which uses the above-mentioned ammonium sulfate wastewater treatment system and comprises the following steps:

[0043] S1, collecting sodium sulfate wastewater into ammonium sulfate wastewater storage tank 5; calcium hydroxide preparation system prepares calcium hydroxide solution;

[0044] S2, the ammonium sulfate wastewater is first subjected to a first heat exchange with the steam in the steam reflux main pipe 17 in the first heat exchanger 8, and then enters the second heat exchanger 9 to conduct a second heat exchange with the steam discharged from the top of the evaporator 11, and finally enters the evaporator 11 quantitatively; the calcium hydroxide solution is quantitatively introduced into the evaporator 11 to react with the ammonium sulfate wastewater, and the pH value in the evaporator 11 is monitored to control the pH value between 9 and 10; the concentrated solution after the reaction is circulated between the tube side of the first circulation heater 13 and the evaporator 11; a part of the steam evaporated from the evaporator 11 enters the shell side of the second circulation heater 20, and the other part enters the second heat exchanger 9;

[0045] S3, the concentrated liquid after being concentrated in the evaporator 11 enters the circulating evaporation crystallization process between the first crystallizer 19 and the second circulating heater 20 through the second bottom circulating pipeline 21, the calcium hydroxide solution is added to the first crystallizer 19 as needed to control the pH value to be between 9 and 10, and the shell side of the second circulating heater 20 is also supplemented with steam in the steam supply system 15 for heating; the concentrated liquid of the tube side of the second circulating heater 20 is sent to the first crystallizer 19; the condensed liquid of the first circulating heater 13 enters the second circulating heater 20 through the first liquid outlet pipe 35;

[0046] S4, the steam at the top of the first crystallizer 19 is supplied to the shell side of the third circulation heater 41; the concentrated liquid from the first crystallizer 19 enters the circulating evaporation crystallization process between the second crystallizer 40 and the third circulation heater 41 through the third bottom circulation pipeline 25, and the calcium hydroxide solution is added to the second crystallizer 40 as needed to control the pH value to be between 9 and 10; the condensed liquid from the second circulation heater 20 enters the shell side of the third circulation heater 41 through the second liquid outlet pipe 36, and the condensed water from the second heat exchanger 9 also enters the shell side of the third circulation heater 41 through the condensed water outlet pipe 34;

[0047] S5, the steam at the top of the second crystallizer 40, the steam of the first circulation heater 13, the second circulation heater 20 and the third circulation heater 41 are introduced into the steam reflux main pipe 17 and finally enter the cooling absorption tower 33 for cooling and then collected by the condensate collection pool 31; the concentrated liquid at the bottom of the second crystallizer 40 is filtered by the filter 29 and the liquid is collected by the mother liquid collection pool 30; the liquid outlet of the third circulation heater 41 is connected to the cooling pool through the third liquid outlet pipe 37. The ammonium sulfate wastewater is further enhanced in heat exchange after the first heat exchange and before the second heat exchange. After the first heat exchange, the ammonium sulfate wastewater enters the third heat exchanger 32 and performs enhanced heat exchange with the condensed water discharged from the third circulation heater 41; the cooling water after heat exchange in the third heat exchanger 32 flows into the cooling pool; the condensed water of the first heat exchanger 8 also flows into the third heat exchanger 32.

[0048] The above-described embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Various modifications and alterations to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An ammonium sulfate wastewater treatment system, characterized in that: include An ammonium sulfate wastewater storage tank is used to collect the ammonium sulfate wastewater storage tank, the ammonium sulfate wastewater storage tank is connected to the wastewater inlet of the first heat exchanger through a first wastewater delivery pipeline, the wastewater outlet of the first heat exchanger is connected to the wastewater inlet of the second heat exchanger, the wastewater outlet on the second heat exchanger is connected to the wastewater inlet of the evaporator through a first liquid inlet pipeline, and the second heat exchanger is also provided with a steam inlet, a steam outlet and a condensed water outlet; the bottom of the evaporator is provided with a first bottom circulation pipeline, the first bottom circulation pipeline is connected to the bottom of the tube side of the first circulation heater, the top of the evaporator is provided to be connected to the steam inlet of the second heat exchanger through a steam recycling pipeline, and the steam outlet of the second heat exchanger is connected to the steam reflux main pipe; the top of the tube side of the first circulation heater is connected to the top of the evaporator through the first top circulation pipeline, and the shell side inlet of the first circulation heater is connected to the steam supply system; the shell side outlet of the first circulation heater is connected to the steam reflux main pipe; A first crystallizer and a second circulation heater, wherein the bottom of the first crystallizer is connected to the bottom tube side of the second circulation heater through a second bottom circulation pipeline, the concentrated liquid outlet on the evaporator is connected to the second bottom circulation pipeline through a first concentrated liquid outflow pipeline, the tube side top of the second circulation heater is connected to the top of the first crystallizer through a second top circulation pipeline, the shell side inlet of the second circulation heater is connected to a steam supply system; and the shell side outlet of the second circulation heater is connected to a steam reflux main pipe; A second crystallizer and a third circulation heater, the bottom of the second crystallizer is connected to the bottom tube side of the third circulation heater through a third bottom circulation pipeline, the concentrated liquid outlet of the first crystallizer is connected to the third bottom circulation pipeline through a second concentrated liquid outflow pipe, the tube side top of the third circulation heater is connected to the top of the second crystallizer through a third top circulation pipeline, the shell side inlet of the third circulation heater is connected to the steam outlet at the top of the first crystallizer; the shell side outlet of the third circulation heater and the top steam outlet of the second crystallizer are both connected to the steam reflux main pipe; the steam reflux main pipe is connected to the steam inlet of the first heat exchanger, and the gas outlet of the first heat exchanger is connected to the negative pressure system; the third bottom circulation pipeline is connected to a concentrated liquid drain pipe, and the concentrated liquid drain pipe is connected to a filter and a mother liquor collection tank; A cooling absorption tower and a condensate collection pool, wherein the steam reflux main pipe is connected to the cooling absorption tower, the bottom of the cooling absorption tower is connected to the condensate collection pool via a condensate outlet pipe, and the condensate collection pool is connected to the top spray port of the cooling absorption tower via a condensate circulation pipeline; The condensate outlet of the second heat exchanger is connected to the liquid inlet of the third circulation heater through the condensate outlet pipe, the liquid outlet of the first circulation heater is connected to the liquid inlet of the second circulation heater through the first liquid outlet pipe, the liquid outlet of the second circulation heater is connected to the liquid inlet of the third circulation heater through the second liquid outlet pipe, and the liquid outlet of the third circulation heater is connected to the cooling tank through the third liquid outlet pipe; The calcium hydroxide configuration system is used for configuring the calcium hydroxide solution, and the calcium hydroxide configuration system is respectively connected to the evaporator, the first crystallizer and the second crystallizer.

2. An ammonium sulfate wastewater treatment system as claimed in claim 1, characterized in that: The treatment system also includes a third heat exchanger, the wastewater inlet of the third heat exchanger is connected to the wastewater outlet of the first heat exchanger, the wastewater outlet of the third heat exchanger is connected to the wastewater inlet of the second heat exchanger, and the liquid inlet and liquid outlet of the third heat exchanger are connected to the third liquid outlet pipe.

3. An ammonium sulfate wastewater treatment system as claimed in claim 2, characterized in that: The wastewater outlet on the second heat exchanger is connected to the top of the first crystallizer through a second liquid inlet pipeline.

4. An ammonium sulfate wastewater treatment system as claimed in claim 3, characterized in that: The top of the evaporator is also connected to the shell side inlet of the first circulation heater through a steam recycling pipeline.

5. An ammonium sulfate wastewater treatment system as claimed in claim 4, characterized in that: The calcium hydroxide configuration system comprises a calcium hydroxide preparation tank, wherein a stirring device is arranged in the calcium hydroxide preparation tank, an outlet of the calcium hydroxide preparation tank is connected with a calcium hydroxide solution storage tank through a calcium hydroxide delivery pipeline, an aeration device is arranged in the calcium hydroxide solution storage tank, and the calcium hydroxide solution storage tank is respectively connected with an evaporator, a first crystallizer and a second crystallizer through a calcium hydroxide solution supply branch pipeline, and a flow meter is arranged on each calcium hydroxide solution supply branch pipeline.

6. A method for treating ammonium sulfate wastewater, characterized in that: The treatment method uses an ammonium sulfate wastewater treatment system as described in any one of claims 1 to 5, comprising the following steps: S1. Collecting sodium sulfate wastewater into an ammonium sulfate wastewater storage tank; the calcium hydroxide preparation system prepares calcium hydroxide solution; S2, the ammonium sulfate wastewater is first subjected to a first heat exchange with the steam in the steam reflux main pipe in the first heat exchanger, and then enters the second heat exchanger to conduct a second heat exchange with the steam discharged from the top of the evaporator, and finally enters the evaporator quantitatively; the calcium hydroxide solution is quantitatively introduced into the evaporator to react with the ammonium sulfate wastewater, and the pH value in the evaporator is monitored to control the pH value between 9 and 10; the concentrated solution after the reaction is circulated between the tube side of the first circulation heater and the evaporator; a part of the steam evaporated from the evaporator enters the shell side of the second circulation heater, and the other part enters the second heat exchanger; S3, the concentrated liquid after evaporation enters the circulating evaporation crystallization process between the first crystallizer and the second circulating heater through the second bottom circulating pipeline, the calcium hydroxide solution is added to the first crystallizer as needed to control the pH value to be between 9-10, and the shell side of the second circulating heater is also heated by the steam supply system; the concentrated liquid of the tube side of the second circulating heater is sent to the first crystallizer; the condensed liquid of the first circulating heater enters the second circulating heater through the first liquid outlet pipe; S4, the steam at the top of the first crystallizer is supplied to the shell side of the third circulation heater; the concentrated liquid from the first crystallizer enters the circulating evaporation crystallization process between the second crystallizer and the third circulation heater through the third bottom circulation pipeline, and the calcium hydroxide solution is added to the second crystallizer as needed to control the pH value to be between 9 and 10; the condensed liquid from the second circulation heater enters the third circulation heater through the second liquid outlet pipe, and the condensed water from the second heat exchanger also enters the third circulation heater through the condensed water outlet pipe; S5, the steam at the top of the second crystallizer, the steam of the first circulation heater, the second circulation heater and the third circulation heater are introduced into the steam reflux main pipe and finally enter the cooling absorption tower to be cooled and collected in the condensate collection pool; the concentrated liquid at the bottom of the second crystallizer is filtered by the filter and the liquid is collected in the mother liquid collection pool; the liquid outlet of the third circulation heater is connected to the cooling pool through the third liquid outlet pipe.

7. A method for treating ammonium sulfate wastewater as claimed in claim 6, characterized in that: The ammonium sulfate wastewater is further subjected to enhanced heat exchange after the first heat exchange and before the second heat exchange. After the first heat exchange, the ammonium sulfate wastewater enters the third heat exchanger for enhanced heat exchange with the condensed water discharged from the third circulation heater; the cooling water after heat exchange in the third heat exchanger flows into the cooling pool; the condensed water from the first heat exchanger also flows into the third heat exchanger.

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