Ammonia-nitrogen wastewater treatment and ammonia water resource recycling device

Abstract

The utility model provides an ammonia-nitrogen wastewater treatment and ammonia water resource recycling device, which is applied to the technical field of wastewater treatment and is characterized in that ammonia-containing steam formed by wastewater in a rectification deamination tower is conveyed into a falling-film evaporator, and kettle liquid is conveyed into a kettle liquid flash tank; the kettle liquid flash tank is connected with the feeding heat exchanger and the steam ejector, the feeding heat exchanger is connected with the rectification deamination tower, the steam ejector is connected with the reboiler and the rectification deamination tower, and the reboiler is respectively connected with the rectification deamination tower and the condensate water tank; the falling film evaporator is respectively connected with the first treatment module, the second treatment module and the third treatment module, and circulating matching treatment of ammonia-containing materials is realized through the first treatment module, the second treatment module and the third treatment module. Latent heat of ammonia-containing steam in the rectification deamination tower is utilized, an efficient falling-film evaporator is adopted, ammonia-containing materials generated by the falling-film evaporator are circularly treated, heat cyclic utilization of secondary steam of the falling-film evaporator is particularly facilitated, and steam consumption and energy consumption are reduced while working efficiency is improved.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to an ammonia nitrogen wastewater treatment and ammonia water resource recovery device. Background Technology

[0002] With the rapid development of my country's economy, many industries such as coking, coal chemical industry, pesticides, fertilizers, light industry, and new energy batteries have discharged a large amount of high-concentration nitrogen-containing wastewater. Excessive nitrogen discharge is an important factor leading to eutrophication of water bodies and water pollution. Wastewater pollution problems also seriously restrict the sustainable development of related industries.

[0003] Treatment methods for ammonia nitrogen wastewater fall into two main categories: ammonia nitrogen transformation treatment and ammonia nitrogen decomposition treatment. Ammonia nitrogen transformation treatment involves converting the ammonia nitrogen in the wastewater into a different form, separating it from the wastewater. These methods mainly include stripping, chemical precipitation, ion exchange, and membrane separation. Ammonia nitrogen decomposition treatment, as the name suggests, destroys the ammonia nitrogen in the wastewater, eliminating its harmful effects. These methods mainly include biological methods and breakpoint chlorination.

[0004] Chemical precipitation is incomplete in removing ammonia nitrogen, and the large amount of reagents required leads to high costs. Excessive reagents can also cause secondary pollution. Ion exchange, membrane separation, and traditional biological methods are not suitable for treating high-ammonia nitrogen wastewater. Breakpoint chlorination is costly to treat high-concentration ammonia nitrogen wastewater, and the organic matter in the water, as well as the formation of chloroform with chlorine, require pretreatment or advanced treatment. Furthermore, the storage and transportation of Cl2 and sodium hypochlorite are inconvenient.

[0005] Stripping methods are divided into air stripping and steam stripping. Air stripping requires a large amount of air, and when the wastewater temperature is low, the ammonia nitrogen removal rate is not high and cannot meet the emission standards. Steam stripping, on the other hand, can increase the wastewater temperature and has a higher ammonia nitrogen removal rate. When there is sufficient separation height, the ammonia nitrogen concentration in the wastewater can reach 5 mg / L or below. However, the traditional stripping method requires a large amount of steam, which is costly. Most of the steam is generated from coal-fired boilers, which belong to a high-carbon industry and do not meet the national energy conservation and carbon reduction policy requirements. Utility Model Content

[0006] In view of the above-mentioned problems in the existing technology, the purpose of this utility model is to provide an ammonia nitrogen wastewater treatment and ammonia water resource recovery device. It utilizes the latent heat of ammonia-containing vapor at the top of the distillation deammoniation tower, adopts a high-efficiency falling film evaporator, and circulates the ammonia-containing materials generated separately. It is particularly beneficial to realize the heat recycling of its secondary steam, improves working efficiency, reduces steam consumption, and reduces energy consumption.

[0007] A device for treating ammonia nitrogen wastewater and recovering ammonia resources includes a distillation deammoniation tower and a falling film evaporator. After pretreatment, the wastewater is fed into the distillation deammoniation tower. The ammonia-containing vapor formed in the distillation deammoniation tower is transferred to the falling film evaporator, and the bottom liquid of the distillation deammoniation tower is transferred to the bottom liquid flash tank.

[0008] The liquid phase from the flash tank is transferred to the feed heat exchanger, and the flash vapor from the flash tank is transferred to the steam ejector. The feed heat exchanger is used to preheat the wastewater and transfer it to the distillation deammoniation tower. The steam ejector is used to generate low-pressure steam to provide a heat source for the reboiler and the distillation deammoniation tower. The reboiler is connected to the distillation deammoniation tower and the condensate tank, respectively. The condensate tank is used to provide condensate for the falling film evaporator.

[0009] The condensate containing ammonia vapor in the falling film evaporator is transferred to the first processing module, the evaporated water vapor in the falling film evaporator is transferred to the second processing module, and the uncondensed ammonia vapor in the falling film evaporator is transferred to the third processing module. The ammonia-containing material is circulated and processed in a coordinated manner through the first, second, and third processing modules.

[0010] Preferably, the first processing module includes a dilute ammonia tank, the condensate containing ammonia vapor in the falling film evaporator is transferred to the dilute ammonia tank, the dilute ammonia tank is connected to the distillation deammoniation tower via a dilute ammonia pump, and the dilute ammonia tank is also connected to an ammonia tank via the dilute ammonia pump.

[0011] Preferably, the second processing module includes a falling film separator and a steam compressor. The evaporated water vapor in the falling film evaporator is transferred to the falling film separator. The falling film separator is connected to the steam compressor. The output end of the steam compressor is connected to a reboiler and a distillation deammoniation tower, respectively.

[0012] Preferably, the third processing module includes an ammonia water injection absorber, an ammonia water condenser, an ammonia water tank, and a tail gas absorption tower. The uncondensed ammonia-containing vapor in the falling film evaporator is transferred to the ammonia water injection absorber. The ammonia water injection absorber is connected to the ammonia water condenser. The ammonia water condenser is connected to the ammonia water tank and the tail gas absorption tower, respectively. The ammonia water tank is connected to the ammonia water injection absorber through an ammonia water circulation pump. The ammonia water tank outputs qualified ammonia water through the ammonia water circulation pump.

[0013] Preferably, the tail gas absorption tower is equipped with an absorption tower circulation pump, and the tail gas absorption tower is connected to a dilute ammonia water tank through the absorption tower circulation pump, and demineralized water is introduced into the absorption tower circulation pump.

[0014] Preferably, the wastewater is stored in a feed tank, which is connected to a pipeline mixer via a feed pump. The pipeline mixer is connected to an alkaline solution to adjust the pH value of the wastewater.

[0015] Preferably, the falling film evaporator is equipped with a falling film circulation pump to realize the material circulation within the falling film evaporator.

[0016] Preferably, the distillation deammoniation tower is connected to the bottom liquid flash tank via a bottom liquid pump, and the bottom liquid flash tank is connected to the feed heat exchanger via a discharge pump.

[0017] Preferably, the condensate tank is connected to the falling film evaporator via a condensate pump.

[0018] The beneficial effects of this utility model are: the ammonia nitrogen wastewater treatment and ammonia water resource recovery device utilizes the latent heat of ammonia-containing vapor at the top of the distillation deammoniation tower, adopts a high-efficiency falling film evaporator, and separately circulates the ammonia-containing materials generated, which is particularly beneficial for the heat recycling of its secondary steam, improving working efficiency while reducing steam consumption and energy consumption.

[0019] By employing a steam ejector, when the quality of fresh steam is high, more low-pressure secondary steam is generated by absorbing the flash steam from the flash tank of the autoclave liquid. This reduces the energy consumption of fresh steam and lowers the operating conditions of the reboiler, achieving economic efficiency.

[0020] The secondary steam, after being heated and pressurized by the steam compressor, can directly enter the distillation deammoniation tower, which can meet the requirement of low temperature rise of a single compressor under a certain ammonia nitrogen influent concentration. However, when using multi-stage compression, the secondary steam can also enter the reboiler to provide heat to the distillation deammoniation tower.

[0021] The ammonia water jet absorber has functions such as vacuuming, condensation, and drainage. Because the ammonia vapor and the jet water flow are in direct contact and exchange heat, most of the ammonia vapor can be condensed into ammonia water and a vacuum environment is formed. The ammonia water condensation and absorption effect is good. At the same time, under vacuum operation conditions, less ammonia gas is released into the environment, making the site environment friendly. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a structural block diagram of the present invention.

[0024] The following are labeled in the diagram: 1. Feed tank; 2. Feed pump; 3. Pipeline mixer; 4. Feed heat exchanger; 5. Steam ejector; 6. Reboiler; 7. Distillation and ammonia removal tower; 8. Boiler liquid pump; 9. Boiler liquid flash tank; 10. Discharge pump; 11. Condensate tank; 12. Condensate pump; 13. Falling film circulation pump; 14. Falling film evaporator; 15. Falling film separator; 16. Steam compressor; 17. Dilute ammonia tank; 18. Dilute ammonia pump; 19. Ammonia tank; 20. Ammonia circulation pump; 21. Ammonia injection absorber; 22. Ammonia condenser; 23. Tail gas absorption tower; 24. Absorption tower circulation pump. Detailed Implementation

[0025] Example 1

[0026] like Figure 1 As shown, an ammonia nitrogen wastewater treatment and ammonia water resource recovery device includes a distillation deammoniation tower 7 and a falling film evaporator 14.

[0027] The distillation deammoniation tower 7 is connected to the feed heat exchanger 4, which in turn is connected to the pipeline mixer 3. The pipeline mixer 3 is connected to the feed tank 1 via the feed pump 2, and the feed heat exchanger 4 is also connected to the flash evaporator 9 via the discharge pump 10. The feed tank 1 stores ammonia nitrogen wastewater, and the pipeline mixer 3 is also connected to an alkaline solution to adjust the pH value of the ammonia nitrogen wastewater. The flash evaporator 9 stores high-temperature materials for heat exchange of the wastewater.

[0028] The distillation deammoniation column 7 is connected to the falling film evaporator 14, which receives ammonia-containing vapor from the top of the column. The falling film evaporator 14 is also connected to a dilute ammonia water tank 17, which transfers the condensate containing the ammonia vapor. The dilute ammonia water tank 17 is connected to the distillation deammoniation column 7 via a dilute ammonia water pump 18, which is also connected to an ammonia water tank 19. A portion of the dilute ammonia water entering the tank 17 is refluxed back to the top of the distillation deammoniation column 7 via the dilute ammonia water pump 18, while the other portion enters the ammonia water tank 19, thus circulating the ammonia water separately.

[0029] In addition, the distillation deammoniation tower 7 is connected to the bottom liquid flash tank 9 via the bottom liquid pump 8 for transferring the bottom liquid. The bottom liquid flash tank 9 is connected to the steam ejector 5, and the steam ejector 5 is connected to the reboiler 6 and the distillation deammoniation tower 7 respectively. A bypass is provided between the reboiler 6 and the distillation deammoniation tower 7.

[0030] The flash evaporator 9 is connected to the feed heat exchanger 4 for heat exchange to pre-treat the ammonia nitrogen wastewater, achieving a preheating effect. Simultaneously, it generates low-pressure steam via the steam ejector 5, providing a heat source for the reboiler 6 and the distillation and ammonia removal tower 7. This circulating heat source effectively improves the efficiency of the recovery unit while also reducing energy consumption.

[0031] Furthermore, the reboiler 6 is also connected to the condensate tank 11, which is also connected to external condensate. The condensate tank 11 is connected to the falling film evaporator 14 via the condensate pump 12 to transfer condensate to it. Furthermore, the falling film evaporator 14 is also connected to a falling film circulation pump 13 to realize the circulation of materials inside the falling film evaporator 14.

[0032] The falling film evaporator 14 is connected to the falling film separator 15, the falling film separator 15 is connected to the input end of the steam compressor 16, and the output end of the steam compressor 16 is connected to the reboiler 6 and the distillation and deammoniation tower 7, respectively.

[0033] The falling film evaporator 14 is also connected to the ammonia water injection absorber 21, which is connected to the ammonia water circulation pump 20 and the ammonia water condenser 22. The ammonia water condenser 22 is connected to the tail gas absorption tower 23 and the ammonia water tank 19, respectively. The ammonia water circulation pump 20 is connected to the ammonia water tank 19. The ammonia water tank 19, the ammonia water circulation pump 20, the ammonia water injection absorber 21, and the ammonia water condenser 22 enable material circulation. Specifically, the ammonia water circulation pump 20 is also connected to an ammonia water delivery pipeline. When the ammonia water concentration reaches the required level, qualified ammonia water is delivered externally through the ammonia water delivery pipeline.

[0034] In addition, an absorption tower circulation pump 24 is connected to the tail gas absorption tower 23. The absorption tower circulation pump 24 is connected to the dilute ammonia water tank 17. An external demineralized water is also connected to the tail gas absorption tower 23. Ammonia gas is absorbed through the absorption tower circulation pump 24, and dilute ammonia water of a certain concentration is sent into the dilute ammonia water tank 17. Qualified non-condensable steam is discharged at high altitude.

[0035] Working principle: In use, the ammonia nitrogen wastewater treatment and ammonia water resource recovery device is operated by pumping the ammonia nitrogen wastewater stored in the feed tank 1 to the pipeline mixer 3 via the feed pump 2. The pH of the wastewater is adjusted by the alkaline solution introduced into the pipeline mixer 3 to make the pH value of the ammonia nitrogen wastewater reach about 12. Then, it is sent to the feed heat exchanger 4 to exchange heat with the high-temperature material feed heat exchanger 4 in the flash tank 9, which is transmitted by the discharge pump 10. After preheating, the wastewater enters the distillation and ammonia removal tower 7.

[0036] The ammonia-containing vapor at the top of the distillation deammoniation column 7 enters the shell side of the falling film evaporator 14. After releasing the latent heat of condensation through evaporation, the ammonia-containing vapor at the top of the distillation deammoniation column 7 is condensed in the falling film evaporator 14. The condensate enters the dilute ammonia water tank 17 and is then refluxed back into the distillation deammoniation column 7 by the dilute ammonia water pump 18.

[0037] The ammonia-removed residue in the distillation stripping column 7 is pumped by the residue pump 8 into the residue flash tank 9. The secondary steam generated by flash evaporation is drawn into the steam ejector 5 by the fresh steam to produce low-pressure steam. This low-pressure steam enters the reboiler 6 to release latent heat or enters the distillation stripping column 7 as a stripping heat source. It should be noted that the reboiler 6 is equipped with a bypass that is directly connected to the distillation stripping column 7 to meet the conditions where the temperature rise is insufficient when using a single compressor, and to meet the conditions when the reboiler 6 needs maintenance.

[0038] The condensate in the reboiler 6 enters the condensate tank 11, and the condensate tank 11 is also connected to external makeup condensate. Then, it is transported to the liquid storage area of ​​the falling film evaporator 14 by the condensate pump 12, and then transported to the top of the falling film evaporator 14 by the falling film circulation pump 13 to enter the distributor for material distribution, and then enter the tube side of the falling film evaporator 14.

[0039] The shell side of the falling film evaporator 14 is connected to the ammonia-containing vapor at the top of the distillation deammoniation column 7. After exchanging heat and condensing, the ammonia-containing vapor at the top of the column enters the dilute ammonia water tank 17. Part of the dilute ammonia water entering the dilute ammonia water tank 17 is refluxed into the top of the distillation deammoniation column 7 through the dilute ammonia water pump 18, and the other part enters the ammonia water tank 19.

[0040] The condensate in the tube side of the falling film evaporator 14 absorbs the latent heat of the ammonia-containing vapor at the top of the column and evaporates and vaporizes before entering the falling film separator 15. After separation, the secondary steam enters the steam compressor 16, is heated and pressurized, and then enters the reboiler 6 or the distillation and ammonia removal tower 7 as a stripping heat source.

[0041] Uncondensed ammonia-containing vapor in the shell side of the falling film evaporator 14 enters the ammonia water injection absorber 21 and the ammonia water circulation pump 20 for injection absorption. The generated ammonia water and uncondensed vapor enter the ammonia water condenser 22 and are condensed and cooled by circulating water before entering the ammonia water tank 19. A qualified ammonia water delivery pipeline is set after the ammonia water circulation pump 20. When the concentration reaches the requirement, qualified ammonia water is sent out.

[0042] Non-condensable steam and a small amount of volatilized ammonia in ammonia water condenser 22 enter tail gas absorption tower 23. Tail gas absorption tower 23 is equipped with absorption tower circulation pump 24, which absorbs ammonia through external replenishment of demineralized water circulation, and sends dilute ammonia water of a certain concentration into dilute ammonia water tank 17, and discharges qualified non-condensable steam at high altitude.

[0043] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An apparatus for treating ammonia-nitrogen wastewater and recycling ammonia water resources, characterized in that, The wastewater is pre-treated and then introduced into the rectification ammonia removal tower (7), ammonia-containing steam formed in the rectification ammonia removal tower (7) is transferred to the falling film evaporator (14), and kettle liquid of the rectification ammonia removal tower (7) is transferred to the kettle liquid flash tank (9); The liquid phase of the kettle liquid flash tank (9) is transferred to the feed heat exchanger (4) for preheating the wastewater and transferring the wastewater to the rectification ammonia removal tower (7), and the flash steam of the kettle liquid flash tank (9) is transferred to the steam ejector (5) for generating low-pressure steam to provide heat sources for the reboiler (6) and the rectification ammonia removal tower (7), the reboiler (6) is connected with the rectification ammonia removal tower (7) and the condensed water tank (11) respectively, and the condensed water tank (11) is used for providing condensed water for the falling film evaporator (14). The condensed water of the ammonia-containing steam in the falling film evaporator (14) is transferred to the first treatment module, the evaporated water vapor in the falling film evaporator (14) is transferred to the second treatment module, and the uncondensed ammonia-containing steam in the falling film evaporator (14) is transferred to the third treatment module, and the first treatment module, the second treatment module and the third treatment module are used for realizing the cyclic and cooperative treatment of the ammonia-containing material.

2. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The first treatment module comprises a dilute ammonia water tank (17), the condensed water of the ammonia-containing steam in the falling film evaporator (14) is transferred to the dilute ammonia water tank (17), the dilute ammonia water tank (17) is connected with the rectification ammonia removal tower (7) through a dilute ammonia water pump (18), and the dilute ammonia water tank (17) is also connected with an ammonia water tank (19) through the dilute ammonia water pump (18).

3. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The second treatment module comprises a falling film separator (15) and a steam compressor (16), the evaporated water vapor in the falling film evaporator (14) is transferred to the falling film separator (15), the falling film separator (15) is connected with the steam compressor (16), and the output end of the steam compressor (16) is connected with the reboiler (6) and the rectification ammonia removal tower (7) respectively.

4. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The third treatment module comprises an ammonia water jet absorber (21), an ammonia water condenser (22), the ammonia water tank (19) and a tail gas absorption tower (23), the uncondensed ammonia-containing steam in the falling film evaporator (14) is transferred to the ammonia water jet absorber (21), the ammonia water jet absorber (21) is connected with the ammonia water condenser (22), the ammonia water condenser (22) is connected with the ammonia water tank (19) and the tail gas absorption tower (23) respectively, the ammonia water tank (19) is connected with the ammonia water jet absorber (21) through an ammonia water circulating pump (20), and the ammonia water tank (19) outputs qualified ammonia water through the ammonia water circulating pump (20).

5. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 4, characterized in that, The tail gas absorption tower (23) is provided with an absorption tower circulating pump (24), the tail gas absorption tower (23) is connected with the dilute ammonia water tank (17) through the absorption tower circulating pump (24), and desalted water is introduced into the absorption tower circulating pump (24).

6. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The wastewater is stored in a feed tank (1), the feed tank (1) is connected with a pipeline mixer (3) through a feed pump (2), the pipeline mixer (3) is connected with lye for adjusting the PH value of the wastewater.

7. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The falling film evaporator (14) is provided with a falling film circulating pump (13) for realizing material circulation in the falling film evaporator (14).

8. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The rectification ammonia removal tower (7) is connected with a kettle liquid flash tank (9) through a kettle liquid pump (8), and the kettle liquid flash tank (9) is connected with the feed heat exchanger (4) through a discharge pump (10).

9. The device for treating ammonia-nitrogen wastewater and recycling ammonia water according to claim 1, characterized in that, The condensate tank (11) is connected with the falling film evaporator (14) through a condensate pump (12).

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