Ammonia-nitrogen wastewater treatment device and ammonia-nitrogen wastewater treatment method

Abstract

The invention relates to the technical field of wastewater treatment, and discloses an ammonia-nitrogen wastewater treatment device and an ammonia-nitrogen wastewater treatment method. According to the embodiment of the invention, the deamination tower, the compression mechanism, the evaporation mechanism, the condenser and the reboiler are matched to construct an efficient steam circulation system, so that the steam can be fully recycled in the ammonia-nitrogen wastewater treatment device, and the use amount of circulating cooling water is reduced; the problem of high ammonia-nitrogen wastewater treatment cost caused by huge live steam consumption in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and specifically relates to an ammonia nitrogen wastewater treatment device and an ammonia nitrogen wastewater treatment method. Background Art

[0002] In the ammonia nitrogen wastewater treatment industry, the ammonia-containing and salt-containing wastewater has complex components and is difficult to treat. The conventional deammonification tower and evaporator in the prior art are separately set up, and although they can produce ammonia water and finished salt respectively, the one-time investment and operating costs are very high. In addition, when the above method is used to treat ammonia nitrogen wastewater, the steam heating consumption is huge, and ammonia condensation requires a large amount of circulating cooling water, which increases the equipment investment of the evaporation system and the overall water treatment cost. Summary of the invention

[0003] The purpose of the present invention is to provide an ammonia nitrogen wastewater treatment device and an ammonia nitrogen wastewater treatment method to solve the problem of high treatment cost caused by excessive use of steam in the ammonia nitrogen wastewater treatment device.

[0004] In order to achieve the above-mentioned object, an embodiment of the present invention provides an ammonia nitrogen wastewater treatment device, the ammonia nitrogen wastewater treatment device comprising: A deamination tower, wherein the top of the deamination tower is provided with an outlet for ammonia-containing steam, and the bottom is provided with an outlet for deamination liquid and an inlet for circulating heating liquid; The evaporation mechanism comprises a primary evaporator, the primary evaporator comprises a hot medium cavity I and a cold medium cavity I, the hot medium cavity I of the primary evaporator comprises a hot medium cavity I inlet, a first hot medium cavity I outlet, and a second hot medium cavity I outlet, the cold medium cavity I of the primary evaporator comprises a cold medium cavity I inlet, a first cold medium cavity I outlet, and a second cold medium cavity I outlet, the hot medium cavity I inlet of the primary evaporator is connected to the ammonia-containing steam outlet of the deamination tower, and the cold medium cavity I inlet of the primary evaporator is connected to the deammoniation liquid outlet of the deamination tower; A condenser, the condenser comprises a hot medium cavity II and a cold medium cavity II, the hot medium cavity II of the condenser comprises a first inlet of the hot medium cavity II, a second inlet of the hot medium cavity II, and a concentrated ammonia outlet, the cold medium cavity II of the condenser comprises an inlet of the cold medium cavity II and an outlet of the cold medium cavity II, the first inlet of the hot medium cavity II of the condenser is connected to the first outlet of the hot medium cavity I of the primary evaporator, and the second inlet of the hot medium cavity II of the condenser is connected to the second outlet of the hot medium cavity I of the primary evaporator; A reboiler, the reboiler comprises a hot medium cavity III and a cold medium cavity III, the hot medium cavity III of the reboiler comprises a hot medium cavity III inlet and a hot medium cavity III outlet, the cold medium cavity III of the reboiler comprises a cold medium cavity III inlet and a cold medium cavity III outlet, the hot medium cavity III inlet of the reboiler is connected to the deammoniation liquid outlet of the deammoniation tower, and the cold medium cavity III outlet of the reboiler is connected to the circulating heating liquid inlet of the deammoniation tower; The compression mechanism comprises a secondary steam inlet and a heating steam outlet, the secondary steam inlet of the compression mechanism is connected to the first outlet of the cold medium cavity I of the primary evaporator, and the heating steam outlet of the compression mechanism is connected to the inlet of the hot medium cavity III of the reboiler.

[0005] In some embodiments, the evaporation mechanism also includes a multi-effect evaporation group, which is used to evaporate and concentrate the liquid after the first-stage evaporation and generate secondary steam II. The multi-effect evaporation group includes a first inlet, a second inlet, a first outlet, a second outlet, and a condensed water outlet. The first inlet of the multi-effect evaporation group is connected to the heating steam outlet of the compression mechanism, the second inlet of the multi-effect evaporation group is connected to the second outlet of the cold medium cavity I of the first-stage evaporator, and the first outlet of the multi-effect evaporation group is connected to the secondary steam inlet of the compression mechanism.

[0006] In some embodiments, the ammonia nitrogen wastewater treatment device also includes a crystallization evaporator, which includes a first inlet, a second inlet, a first outlet, a second outlet, and a condensed water outlet. The first inlet of the crystallization evaporator is connected to the heating steam outlet of the compression mechanism, the second inlet of the crystallization evaporator is connected to the second outlet of the multi-effect evaporation group, and the first outlet of the crystallization evaporator is connected to the secondary steam inlet of the compression mechanism.

[0007] In some embodiments, the compression mechanism includes a primary compressor and a secondary compressor, the primary compressor is provided with a secondary steam inlet and a first heated steam outlet, and the secondary compressor is provided with a steam inlet and a second heated steam outlet; The secondary steam inlet of the primary compressor is connected to at least one of the first outlet of the cold medium cavity I of the primary evaporator, the first outlet of the multi-effect evaporation group, and the first outlet of the crystallization evaporator; The first heating steam outlet of the primary compressor is connected to the steam inlet of the secondary compressor, the first inlet of the multi-effect evaporation group, and the first inlet of the crystallization evaporator; The second heating port of the secondary compressor is connected to the inlet of the heat medium cavity III of the reboiler.

[0008] In some embodiments, the multi-effect evaporation group includes a first-effect evaporator and a second-effect evaporator connected in series.

[0009] In some embodiments, the ammonia nitrogen wastewater treatment device also includes a condensate tank, the multiple-effect evaporation group is provided with a condensate outlet, and the condensate tank is connected to at least one of the condensate outlet of the multiple-effect evaporation group, the heat medium cavity III outlet of the reboiler, and the condensate outlet of the crystallization evaporator.

[0010] In some embodiments, the ammonia nitrogen wastewater treatment device further includes a filter disposed between the primary evaporator and the multiple-effect evaporation group.

[0011] In some embodiments, the ammonia nitrogen wastewater treatment device also includes a preheating system.

[0012] In some embodiments, a method for treating ammonia nitrogen wastewater is proposed, which is applied to the above ammonia nitrogen wastewater treatment device, and the method for treating ammonia nitrogen wastewater includes: S100: passing the ammonia nitrogen wastewater into a deammonification tower for gas-liquid separation pretreatment to obtain deammonified liquid and ammonia-containing steam; S200: passing ammonia-containing steam into the heat medium cavity I of the primary evaporator for preliminary condensation to obtain high-ammonia steam and condensed water; Passing a portion of the deammoniation liquid into the cold medium cavity I of the primary evaporator for primary evaporation to obtain the primary evaporated liquid and secondary steam I; Passing the secondary steam I into the compression mechanism, compressing and pressurizing the secondary steam I to obtain heating steam; The other part of the liquid after deammoniation is passed into the cold medium cavity III of the reboiler, and the heating steam is passed into the hot medium cavity III of the reboiler to obtain condensed water; S300: The high ammonia vapor is passed into the heat medium cavity II of the condenser and is secondary condensed with cooling water to obtain concentrated ammonia water.

[0013] In some embodiments, the method for treating ammonia nitrogen wastewater further comprises: S400: passing the heating steam and the liquid after the primary evaporation into the multi-effect evaporation group to obtain concentrated liquid, secondary steam II and condensed water; S500: passing the heating steam and the concentrated liquid into a crystallization evaporator for evaporation and crystallization to obtain crystal slurry, secondary steam III and condensed water; Passing secondary steam II and secondary steam III into the compression mechanism; S600: The crystal slurry is passed into a centrifugal salt outlet system for processing to obtain finished salt.

[0014] Through the above technical scheme, the ammonia nitrogen wastewater treatment device and ammonia nitrogen wastewater treatment method provided by the embodiments of the present invention have the following beneficial effects: This embodiment can construct an efficient steam circulation system through the coordination of a deammonification tower, a compression mechanism, an evaporation mechanism, a condenser and a reboiler, ensuring that the steam can be fully recycled in the ammonia nitrogen wastewater treatment device, reducing the use of circulating cooling water, and solving the problem of high ammonia nitrogen wastewater treatment cost caused by huge steam consumption in the prior art.

[0015] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative work. In the accompanying drawings: Figure 1 is a flow chart of an ammonia nitrogen wastewater treatment device according to some embodiments of the present invention; Figure 2 Schematic diagram of the structure of an ammonia nitrogen wastewater treatment device according to some embodiments of the present invention; Figure 3 The present invention is a flowchart of a method for treating ammonia nitrogen wastewater according to some embodiments of the present invention.

[0017] Description of Reference Numerals 1. Deamination tower; 2. Reboiler; 31. Primary evaporator; 321. Primary heater; 322. Primary gas-liquid separator; 323. Secondary heater; 324. Secondary gas-liquid separator; 41. Primary compressor; 42. Secondary compressor; 5. Condenser; 6. Filter; 7. Centrifugal salt removal system; 81. Triple heater; 82. Crystallizer; 9. Vacuum system; 10. Preheating system. DETAILED DESCRIPTION

[0018] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0019] The following describes the ammonia nitrogen wastewater treatment device and the ammonia nitrogen wastewater treatment method according to the present invention with reference to the accompanying drawings.

[0020] like Figure 1 or Figure 2 As shown, in this embodiment, an ammonia nitrogen wastewater treatment device is proposed, which includes a deammoniation tower 1, an evaporation mechanism, a reboiler 2, a compression mechanism and a condenser 5.

[0021] The deammoniation tower 1 is used to treat ammonia nitrogen wastewater and obtain deammoniation liquid and ammonia-containing steam. The top of the deammoniation tower 1 is provided with an ammonia-containing steam outlet, and the bottom is provided with a deammoniation liquid outlet and a circulating heating liquid inlet.

[0022] The evaporation mechanism includes a primary evaporator 31, which is used to evaporate and concentrate the deammonified liquid, partially condense the ammonia-containing steam, and generate secondary steam I. The primary evaporator 31 includes a hot medium cavity I and a cold medium cavity I. The hot medium cavity I of the primary evaporator 31 includes a hot medium cavity I inlet, a first hot medium cavity I outlet, and a second hot medium cavity I outlet. The cold medium cavity I of the primary evaporator 31 includes a cold medium cavity I inlet, a first cold medium cavity I outlet, and a second cold medium cavity I outlet. The hot medium cavity I inlet of the primary evaporator 31 is connected to the ammonia-containing steam outlet of the deammonification tower 1 to pass the ammonia-containing steam from the deammonification tower 1 into the hot medium cavity I of the primary evaporator. The cold medium cavity I inlet of the primary evaporator 31 is connected to the deammonified liquid outlet of the deammonification tower 1 to pass the deammonified liquid from the deammonification tower 1 into the cold medium cavity I of the primary evaporator 31. In this way, the ammonia-containing steam is partially condensed to obtain high-ammonia steam.

[0023] The condenser 5 is used to condense high-ammonia steam. The condenser 5 includes a hot medium cavity II and a cold medium cavity II. The hot medium cavity II of the condenser 5 includes a first inlet of the hot medium cavity II, a second inlet of the hot medium cavity II, and a concentrated ammonia water outlet. The cold medium cavity II of the condenser 5 includes an inlet of the cold medium cavity II and an outlet of the cold medium cavity II. The first inlet of the hot medium cavity II of the condenser 5 is connected to the first outlet of the hot medium cavity I of the primary evaporator 31 to pass the high-ammonia steam and into the hot medium cavity II of the condenser 5. The second inlet of the hot medium cavity II of the condenser 5 is connected to the second outlet of the hot medium cavity I of the primary evaporator 31 to pass cooling water into the cold medium cavity. In this way, the high-ammonia steam and can be converted into concentrated ammonia water and discharged.

[0024] Reboiler 2, reboiler 2 includes a hot medium cavity III and a cold medium cavity III, the hot medium cavity III of the reboiler 2 includes a hot medium cavity III inlet and a hot medium cavity III outlet, the cold medium cavity III of the reboiler 2 includes a cold medium cavity III inlet and a cold medium cavity III outlet, the hot medium cavity III inlet of the reboiler 2 is connected to the deaminated liquid outlet of the deaminated tower 1, and the cold medium cavity III outlet of the reboiler 2 is connected to the circulating heating liquid inlet of the deaminated tower 1, so that part of the deaminated liquid discharged from the deaminated tower 1 is passed into the reboiler 2 for heating and then circulated back to the deaminated tower 1.

[0025] The compression mechanism is used to convert the secondary steam into heating steam for recycling. The compression mechanism includes a secondary steam inlet and a heating steam outlet. The secondary steam inlet of the compression mechanism is connected to the first outlet of the cold medium cavity I of the primary evaporator 31, and the heating steam outlet of the compression mechanism is connected to the inlet of the hot medium cavity III of the reboiler 2, so as to obtain the secondary steam I. The secondary steam I enters the compression mechanism from the first outlet of the cold medium cavity I of the primary evaporator 31, and is converted into heating steam and then transported to the hot medium cavity III of the reboiler 2 as the heat source of the reboiler 2. The heating steam is converted into condensed water in the hot medium cavity III of the reboiler 2 and discharged. The discharged condensed water can be used as cooling water in the condenser 5. It can be seen that the consumption of raw steam and cooling water is effectively reduced through the arrangement of the deamination tower 1, the evaporation mechanism, the condenser 5, and the reboiler 2 in this embodiment.

[0026] It should be noted that the live steam in the embodiment of the present invention refers to fresh saturated water vapor, which is usually used as a heating source in the evaporation operation. The hot medium cavity and the cold medium cavity can be cavities in the pipeline of the device, or cavities formed between the pipeline and the device shell.

[0027] In some embodiments, the outlet of the deammoniation tower 1 and the inlet of the cold medium cavity I of the primary evaporator 31 are connected through a first deammoniation liquid pipeline, and a second deammoniation liquid pipeline as a branch pipeline is provided on the first deammoniation liquid pipeline, one end of the second deammoniation liquid pipeline is connected to the inlet of the cold medium cavity III of the reboiler 2, and the other end is connected to the first deammoniation liquid pipeline. In this way, a part of the deammoniation liquid can be passed into the primary evaporator 31 for treatment, and a part of the deammoniation liquid can be passed into the reboiler 2 for treatment.

[0028] In some embodiments, the cold medium cavity I of the primary evaporator 31 is further provided with a reflux port, and the second outlet of the cold medium cavity I of the primary evaporator 31 is connected to the reflux port of the cold medium cavity I of the primary evaporator 31 through a primary evaporation liquid pipeline. A primary evaporation liquid pipeline is provided with a primary evaporation liquid reflux branch, one end of which is connected to the second outlet of the cold medium cavity I of the primary evaporator 31, and the other end is connected to the primary evaporation liquid pipeline.

[0029] In some embodiments, the cold medium cavity I of the primary evaporator 31 is also provided with a sprayer, which is connected to the return port of the cold medium cavity I of the primary evaporator 31 to improve the heat exchange effect with the ammonia vapor contained in the hot medium cavity I and promote the formation of secondary steam I.

[0030] It can be understood that, through the configuration of the above embodiment, the gas volume of secondary steam in the system can be effectively increased, thereby improving the utilization rate of heat and the output of condensed water, reducing the consumption of raw steam and cooling water, and reducing the requirements of the rear-end evaporation system such as the multi-effect evaporation group for the output of secondary steam, effectively reducing the investment and operating costs of the rear-end evaporation system. In the above embodiment, illustratively, the deammoniated liquid is passed into the cold medium cavity I of the primary evaporator 31, and the ammonia-containing steam is passed into the hot medium cavity I of the primary evaporator 31 for heat exchange. In this process, about 5%-10% of the water will evaporate, and the water evaporation range of the deammoniated liquid itself by flash evaporation is 2%-5%.

[0031] In some embodiments, the deamination tower 1 is further provided with a reflux port, and the second outlet of the heat medium cavity I of the primary evaporator 31 is connected to the second inlet of the heat medium cavity II of the condenser 5 through a pipeline. A reflux branch is provided on the pipeline, one end of the reflux branch is connected to the reflux port of the deamination tower 1, and the other end is connected to the pipeline to partially reflux to the deamination tower 1 to supplement the ammonia concentration in the deamination tower 1.

[0032] In some embodiments, a reflux port is provided on the heat medium cavity II of the condenser 5, and a concentrated ammonia water pipeline is connected to the second outlet of the heat medium cavity II of the condenser 5, and a concentrated ammonia water reflux branch is provided on the concentrated ammonia water pipeline. One end of the concentrated ammonia water reflux branch is connected to the reflux port of the condenser 5, and the other end is connected to the concentrated ammonia water pipeline. The concentration of the output concentrated ammonia water can be adjusted by controlling the reflux ratio of the concentrated ammonia water to obtain a preset concentrated ammonia water concentration.

[0033] In some embodiments, the evaporation mechanism further includes a multi-effect evaporation group, which is used to evaporate and concentrate the first-stage evaporation liquid and generate secondary steam II. The multi-effect evaporation group includes a first inlet, a second inlet, a first outlet, a second outlet, and a condensed water outlet. The first inlet of the multi-effect evaporation group is connected to the heating steam outlet of the compression mechanism, the second inlet of the multi-effect evaporation group is connected to the second outlet of the cold medium cavity I of the first evaporator, and the first outlet of the multi-effect evaporation group is connected to the secondary steam inlet of the compression mechanism. In this embodiment, the first-stage evaporation liquid obtained by the first-stage evaporator 31 is introduced from the second inlet of the multi-effect evaporation group, and evaporated and concentrated using the heating steam discharged from the compression mechanism to obtain concentrated liquid, secondary steam II and condensed water. The concentrated liquid is discharged from the second outlet of the multi-effect evaporation group; the secondary steam II is discharged from the first outlet of the multi-effect evaporation group and introduced into the compression mechanism to be converted into heating steam; the condensed water is discharged from the condensed water outlet of the multi-effect evaporation group.

[0034] It can be understood that the multiple-effect evaporation group includes a plurality of evaporators connected in series, such as Figure 1 As shown in , it can be represented as a 1-N effect evaporator. The number of evaporators can be adjusted according to actual needs.

[0035] In some embodiments, the ammonia nitrogen wastewater treatment device also includes a crystallization evaporator, the crystallization evaporator includes a first inlet, a second inlet, a first outlet, a second outlet, and a condensed water outlet, the first inlet of the crystallization evaporator is connected to the heating steam outlet of the compression mechanism, the second inlet of the crystallization evaporator is connected to the second outlet of the multi-effect evaporation group, and the first outlet of the crystallization evaporator is connected to the secondary steam inlet of the compression mechanism. In this embodiment, the heating steam is introduced from the first inlet of the crystallization evaporator, the concentrated liquid is introduced from the second inlet of the crystallization evaporator, the crystal slurry and secondary steam III are obtained in the crystallization evaporator, the secondary steam III is discharged from the first outlet of the crystallization evaporator, and is introduced into the compression mechanism from the secondary steam inlet of the compression mechanism, so that the secondary steam III is converted into heating steam; the crystal slurry is discharged from the second outlet of the crystallization evaporator.

[0036] It can be understood that in the above embodiment, the secondary steam produced in the primary evaporator 31, the multi-effect evaporation group, and the crystallization evaporator is passed into the compression mechanism, which can not only effectively increase the overall secondary steam volume in the system, but also indirectly improve the operating efficiency of the compression mechanism, making the selection range of the compression mechanism wider. Exemplarily, the compression mechanism adopts a steam compressor.

[0037] In some embodiments, the ammonia nitrogen wastewater treatment device also includes a centrifugal salt extraction system 7, and the centrifugal salt extraction device is connected to the crystallization evaporator to centrifugally treat the slurry obtained by the crystallization evaporator to obtain an industrial salt product.

[0038] In some embodiments, the compression mechanism includes a primary compressor 41 and a secondary compressor 42, the primary compressor 41 is provided with a secondary steam inlet and a first heating steam outlet, and the secondary compressor 42 is provided with a first heating steam inlet and a second heating steam outlet. The secondary steam inlet of the primary compressor 41 is connected to at least one of the first outlet of the cold medium cavity I of the primary evaporator 31, the first outlet of the multi-effect evaporation group, and the first outlet of the crystallization evaporator, so as to convert the secondary steam I, secondary steam II, and secondary steam III obtained in the primary evaporator 31, the multi-effect evaporation group, and the crystallization evaporator into heating steam. The first heating steam outlet of the primary compressor 41 is connected to at least one of the first heating steam inlet of the secondary compressor 42, the first inlet of the multi-effect evaporation group, and the first inlet of the crystallization evaporator, and the second heating outlet of the secondary compressor 42 is connected to the inlet of the hot medium cavity III of the reboiler 2, so as to further compress and pressurize the first heating steam obtained in the primary compressor 41 to obtain the second heating steam, and serve as the heat source of the primary evaporator 31, the multi-effect evaporation group, and the crystallization evaporator.

[0039] In some embodiments, the multi-effect evaporation group includes a first-effect evaporator and a second-effect evaporator connected in series to fully utilize the secondary steam generated in the system and ensure that the amount of heating steam produced by the compression mechanism is sufficient. If more evaporators are provided, the working efficiency of the compressor needs to be increased accordingly, which may easily lead to an increase in the capital investment in the ammonia nitrogen wastewater treatment device.

[0040] In some embodiments, the first-effect evaporator is provided with a first inlet for introducing heating steam, and a second inlet for introducing liquid after primary evaporation. The liquid after primary evaporation is subjected to first-effect evaporation in the first-effect evaporator to obtain secondary steam and liquid after primary evaporation; the second-effect evaporator is provided with a second inlet for introducing liquid after primary evaporation, and a first inlet for introducing secondary steam generated in the first-effect evaporator as a heat source, and concentrated liquid and secondary steam II are obtained in the second-effect evaporator; the second-effect evaporator is also provided with a first outlet, which is connected to the secondary steam inlet of the compression mechanism, so that the secondary steam II is introduced into the compression mechanism to be converted into heating steam for recycling, and is also provided with a second outlet, which is connected to the crystallization evaporator.

[0041] Furthermore, a reflux port is provided on the top of the first-effect evaporator and the second-effect evaporator, the second outlet of the first-effect evaporator is connected to the second inlet of the second-effect evaporator through a first-effect evaporation liquid rear pipe, a first-effect evaporation liquid rear reflux branch is provided on the first-effect evaporation liquid rear pipe, one end of the first-effect evaporation liquid rear reflux branch is connected to the reflux port of the first-effect evaporator, and the other end is communicated with the first-effect evaporation liquid rear pipe; the second outlet of the second-effect evaporator is connected to the crystallization evaporator through a second-effect evaporation liquid rear pipe, a second-effect evaporation liquid rear reflux branch is provided on the second-effect evaporation liquid rear pipe, one end of the second-effect evaporation liquid rear reflux branch is connected to the reflux port of the second-effect evaporator, and the other end is communicated with the second-effect evaporation liquid rear pipe.

[0042] In some embodiments, the first-effect evaporator includes a first-effect heater 321 and a first-effect gas-liquid separator 322 , and the second-effect evaporator includes a second-effect heater 323 and a second-effect gas-liquid separator 324 .

[0043] In some embodiments, the first-effect heater 321 is provided with a hot medium cavity IV and a cold medium cavity IV, and the second-effect heater 323 is provided with a hot medium cavity V and a cold medium cavity V. In addition, the hot medium cavity IV of the first-effect heater 321 is provided with a heating steam inlet and a condensed water outlet, and the hot medium cavity V of the second-effect heater 323 is also provided with a mixed steam inlet and a condensed water outlet. The cold medium cavity IV of the first-effect heater 321 is provided with a first-stage evaporation liquid inlet, a mixed steam outlet, and a reflux port, and the cold medium cavity V of the second-effect heater 323 is also provided with a first-stage evaporation liquid inlet, a mixed steam outlet, and a reflux port. The cold medium cavity IV of the first-effect heater 321 is provided with a first-effect evaporation liquid outlet, and the cold medium cavity V of the second-effect heater 323 is provided with a second-effect evaporation liquid outlet. The first-effect gas-liquid separator 322 and the second-effect gas-liquid separator 324 are both provided with a mixed steam inlet on the side, a first outlet on the top, and a second outlet on the bottom.

[0044] The heating steam inlet of the first-effect heater 321 is connected to the first heating steam outlet of the first-stage compressor 41 so that the heating steam is passed into the first-effect heater 321 as a heat source. The heating steam exchanges heat with the solution in the cold medium cavity IV of the first-effect heater 321 to obtain condensed water, which is discharged from the condensed water outlet of the first-effect heater 321.

[0045] The first-stage evaporated liquid inlet of the first-effect heater 321 is connected to the second outlet of the cold medium cavity I of the first-stage evaporator 31, so that the first-stage evaporated liquid is passed into the first-effect heater 321, and evaporated and concentrated in the first-effect evaporator to obtain the first-effect evaporated liquid and mixed steam.

[0046] The mixed steam outlet of the first-effect heater 321 is connected to the mixed steam inlet of the first-effect gas-liquid separator 322, and the secondary steam and the first-effect evaporation liquid in the mixed steam generated by the first-effect heater are separated by the first-effect gas-liquid separator 322. The first-effect evaporation liquid outlet of the first-effect heater 321 and the second outlet of the first-effect gas-liquid separator 322 are both connected to the first-stage evaporation liquid inlet of the second-effect heater 323 through the first-effect evaporation liquid pipeline, so that the first-effect evaporation liquid is passed into the heat medium cavity V of the second-effect heater 323.

[0047] The first outlet of the first-effect gas-liquid separator 322 is connected to the mixed steam inlet of the second-effect heater 323, so that the secondary steam generated in the first-effect evaporator is used as the heat source for the second-effect evaporation, and is discharged from the condensed water outlet after being converted into condensed water in the second-effect heater 323. The liquid after the first-effect evaporation is converted into the liquid after the second-effect evaporation and mixed steam in the second-effect heater 323.

[0048] The mixed steam outlet of the second-effect heater 323 is connected to the mixed steam inlet of the second-effect gas-liquid separator 324, so that the second-effect gas-liquid separator is used to separate the secondary steam II and the second-effect evaporation liquid in the mixed steam obtained in the second-effect heater 323. The first outlet of the second-effect gas-liquid separator 324 is connected to the secondary steam inlet of the primary compressor 41, and the second-effect evaporation liquid outlet of the second-effect heater 323 and the second outlet of the second-effect gas-liquid separator are both connected to the crystallization evaporator through the second-effect evaporation liquid pipeline, so that the second-effect evaporation liquid is passed into the crystallization evaporator.

[0049] A first-effect evaporation liquid reflux branch is also provided on the first-effect evaporation liquid pipeline, one end of which is connected to the reflux port of the first-effect heater 321, and the other end is connected to the first-effect evaporation liquid pipeline to reflux the first-effect evaporation liquid to the first-effect heater 321.

[0050] A second-effect evaporation liquid reflux branch is also provided on the second-effect evaporation liquid pipeline, one end of which is connected to the reflux port of the second-effect heater 323, and the other end is connected to the second-effect evaporation liquid pipeline to reflux the second-effect evaporation liquid to the second-effect heater 323.

[0051] In some embodiments, the ammonia nitrogen wastewater treatment device also includes a condensate tank, which is provided with a water inlet and a water outlet, and the multiple-effect evaporation group is provided with a condensate outlet, and the water inlet of the condensate tank is connected to at least one of the condensate outlet of the multiple-effect evaporation group, the outlet of the heat medium cavity III of the reboiler 2, and the condensate outlet of the crystallization evaporator.

[0052] In some embodiments, the ammonia nitrogen wastewater treatment device further includes a filter 6 disposed between the primary evaporator 31 and the multiple-effect evaporation group. The filter 6 is used to filter the primary evaporation liquid to reduce the influence of solid particles such as metal foreign matter on subsequent evaporation concentration. Further, the inlet of the filter 6 is connected to the second outlet of the primary evaporator 31, the outlet of the filter 6 is connected to the second inlet of the multiple-effect evaporation group, or the outlet of the filter 6 is connected to the primary evaporation liquid inlet of the primary effect heater 321.

[0053] In some embodiments, the crystallization evaporator includes a triple effect heater 81 and a crystallization separator 82 .

[0054] The triple-effect heater 81 includes a hot medium cavity VI and a cold medium cavity VI. A heating steam inlet and a condensed water outlet are provided in the hot medium cavity VI, and an inlet and an outlet are provided in the cold medium cavity VI.

[0055] The crystal separator 82 is provided with a circulating heating liquid inlet and a third outlet, and a second inlet and a first outlet are provided at the top of the crystal separator 82, and a second outlet is provided at the bottom.

[0056] The heating steam inlet of the triple-effect heater 81 is connected to the first heating steam outlet of the primary compressor 41, so that the heating steam is passed into the triple-effect heater 81. The heating steam is converted into condensed water in the triple-effect heater 81 and discharged from the condensed water outlet. The inlet of the cold medium cavity VI of the triple-effect heater 81 is connected to the third outlet of the crystal separator 82, and the outlet of the cold medium cavity VI of the triple-effect heater 81 is connected to the circulating heating liquid inlet of the crystal separator 82, so as to circulate and heat the feed liquid in the crystal separator.

[0057] The second-effect evaporation liquid outlet of the second-effect heater 323 and the second outlet of the second-effect gas-liquid separator 324 are both connected to the second inlet of the crystallizer 82, so that the second-effect evaporation liquid is passed into the crystallizer 82. The first outlet of the crystallizer 82 is connected to the secondary steam inlet of the primary compressor 41. The second-effect evaporation liquid is further processed in the crystallizer 82 to obtain crystal slurry and secondary steam III. The crystal slurry is discharged from the second outlet of the crystallizer 82, and the secondary steam III is discharged from the first outlet of the crystallizer 82 and passed into the primary compressor 41.

[0058] In some embodiments, a reflux port is further provided at the top of the crystal separator 82, and the second outlet of the crystal separator 82 is connected to the centrifugal salt outlet system 7 through a slurry pipeline. A slurry reflux branch is provided on the slurry pipeline, one end of the slurry reflux branch is connected to the reflux port of the crystal separator 82, and the other end is connected to the slurry pipeline.

[0059] In some embodiments, the ammonia nitrogen wastewater treatment device further includes a feed tank and a preheating system 10. The feed tank is used to store ammonia nitrogen wastewater. The preheating system 10 is arranged between the feed tank and the deamination tower 1, and is used to heat the ammonia nitrogen wastewater. The ammonia nitrogen wastewater is heated by passing through the preheating system from the feed tank, and then passed through the deamination tower 1 for treatment.

[0060] In some embodiments, the preheating system 10 includes a condensate preheater and an exhaust gas preheater. The condensate preheater is provided with a hot medium cavity VII and a cold medium cavity VII, and the exhaust gas preheater is provided with a hot medium cavity VIII and a cold medium cavity VIII; the condenser 5, the primary evaporator 31, the first-effect evaporator, the second-effect evaporator, and the crystallization evaporator are also provided with an exhaust gas outlet, which is connected to the hot medium cavity VIII of the exhaust gas preheater; the condensate tank outlet is connected to the hot medium cavity VII of the condensate preheater; the feed tank is connected to the cold medium cavity VII of the condensate preheater and the cold medium cavity VIII of the exhaust gas preheater in sequence.

[0061] In some embodiments, the ammonia nitrogen wastewater treatment device further includes a vacuum system 9 and a tail gas tower. The tail gas produced by the condenser 5, the primary evaporator 31, the first effect evaporator, the second effect evaporator and the crystallization evaporator is extracted by the vacuum system 9 and sent to the tail gas tower for treatment.

[0062] like Figure 3 As shown, in this embodiment, a method for treating ammonia nitrogen wastewater is also proposed, which is applied to the above ammonia nitrogen wastewater treatment device. The method for treating ammonia nitrogen wastewater includes: S100: passing the ammonia nitrogen wastewater into a deammonification tower 1 for gas-liquid separation pretreatment to obtain deammonified liquid and ammonia-containing steam; S200: passing ammonia-containing steam into the heat medium cavity I of the primary evaporator 31 for preliminary condensation to obtain high-ammonia steam and; A portion of the deammoniation liquid is passed into the cold medium cavity I of the primary evaporator 31 to perform primary evaporation to obtain the primary evaporated liquid and secondary steam I; The other part of the deammoniation liquid is passed into the cold medium cavity III of the reboiler 2, and returned to the deammoniation tower 1 after heating, and the heating steam is passed into the hot medium cavity III of the reboiler 2 to obtain condensed water; Passing the secondary steam I into the compression mechanism, compressing and pressurizing the secondary steam I to obtain heating steam; S300: The high ammonia vapor is passed into the heat medium cavity II of the condenser 5 and is secondary condensed with cooling water to obtain concentrated ammonia water.

[0063] In some embodiments, the method for treating ammonia nitrogen wastewater further comprises: S400: passing the heating steam and the liquid after the primary evaporation into the multi-effect evaporation group for evaporation and concentration to obtain concentrated liquid, secondary steam II and condensed water; S500: passing the heated steam and the concentrated liquid into a crystallization evaporator for evaporation and crystallization to obtain crystal slurry, secondary steam III and condensed water, and centrifuging the crystal slurry to obtain finished salt; Passing secondary steam II and secondary steam III into the compression mechanism; S600: The crystal slurry is passed into the centrifugal salt outlet system 7 for treatment to obtain finished salt.

[0064] In some embodiments, step S200 further includes S210: refluxing a portion of the solution to the deamination tower 1 to adjust the concentration of the concentrated ammonia solution; S220: returning a portion of the liquid after primary evaporation to the cold medium cavity I of the primary evaporator; Step S300 also includes S310 returning a portion of the concentrated ammonia water to the heat medium cavity II of the condenser 5 .

[0065] In the above embodiment, the concentration of the concentrated ammonia water finally produced can be adjusted by controlling the amount of the concentrated ammonia water reflux.

[0066] In some embodiments, the compression and pressurization of secondary steam I, secondary steam II, and secondary steam III include a first compression and pressurization performed in a primary compressor 41 and a second compression and pressurization performed in a secondary compressor 42; the heating steam obtained by the primary compressor 41 is passed into a multi-effect evaporation group and a crystallization evaporator as a heat source, and the heating steam obtained by the secondary compressor 42 is passed into a reboiler 2 as a heat source.

[0067] In some embodiments, the ammonia nitrogen wastewater treatment method also includes preheating: the ammonia nitrogen wastewater is preheated before passing into the deammonification tower, and the preheating heat source includes condensed water and tail gas; the condensed water is generated from the reboiler 2, the multiple-effect evaporation group, and the crystallization evaporator, and the tail gas is generated from the primary evaporator 31, the condenser 5, the reboiler 2, the multiple-effect evaporation group, and the crystallization evaporator.

[0068] In some embodiments, step S400 further includes filtering the primary evaporated liquid before passing through the multi-effect evaporation group.

[0069] In addition, in order to facilitate the understanding of the treatment process of ammonia nitrogen wastewater, the entire process of ammonia nitrogen wastewater treatment is further explained as follows: Preheating: The ammonia nitrogen wastewater is preheated by passing through the condenser preheater and the tail gas preheater in sequence; Specifically, the heat source for preheating includes condensed water and tail gas; the condensed water is generated from the reboiler 2, the multi-effect evaporation group, and the crystallization evaporator, and the tail gas is generated from the primary evaporator 31, the condenser 5, the reboiler 2, the multi-effect evaporation group, and the crystallization evaporator.

[0070] S100: passing the ammonia nitrogen wastewater into a deammonification tower 1 for gas-liquid separation pretreatment to obtain deammonified liquid and ammonia-containing steam; S200: passing ammonia-containing steam into the heat medium cavity I of the primary evaporator 31 for preliminary condensation to obtain high-ammonia steam and; A portion of the deammoniation liquid is passed into the cold medium cavity I of the primary evaporator 31 to perform primary evaporation to obtain the primary evaporated liquid and secondary steam I; The other part of the deammoniation liquid is passed into the cold medium cavity III of the reboiler 2, and returned to the deammoniation tower 1 after heating, and the heating steam is passed into the hot medium cavity III of the reboiler 2 to obtain condensed water; specifically, the heating steam passed into the reboiler is the heating steam generated by the secondary compressor 42; Passing the secondary steam I into the compression mechanism, compressing and pressurizing the secondary steam I to obtain heating steam; Specifically, the compression and pressurization includes a first compression and pressurization and a second compression and pressurization performed in sequence by a primary compressor 41 and a secondary compressor 42. S210: reflux a portion of the water to the deamination tower 1 to adjust the concentration of concentrated ammonia water; S220: returning a portion of the liquid after primary evaporation to the cold medium cavity I of the primary evaporator; S300: The high ammonia vapor is passed into the heat medium cavity II of the condenser 5 and is subjected to secondary condensation with cooling water to obtain concentrated ammonia water; specifically, the cooling water is passed into the cold medium cavity II of the condenser 5 for secondary condensation; S310: reflux a portion of the concentrated aqueous ammonia to the heat medium cavity II of the condenser 5; Control the reflux rate of concentrated ammonia water to adjust the concentration of the final concentrated ammonia water output; S400: passing the heating steam and the liquid after the primary evaporation into the multi-effect evaporation group for evaporation and concentration to obtain concentrated liquid, secondary steam II and condensed water; Before the primary evaporation liquid is passed into the multi-effect evaporation group, the primary evaporation liquid is passed into the filter 6 for filtration; Specifically, the liquid after the first-stage evaporation is passed into the first-effect evaporator for first-effect evaporation to obtain the liquid after the first-effect evaporation and raw steam; the liquid after the first-effect evaporation is passed into the second-effect evaporator for second-effect evaporation to obtain concentrated liquid and secondary steam II; the heat source of the first-effect evaporation process is the heating steam generated by the first-effect compressor 41, which is converted into condensed water in the first-effect evaporation; the heat source of the second-effect evaporation process is the secondary steam generated in the first-effect evaporation, which is converted into condensed water in the second-effect evaporation; the secondary steam II is passed into the first-effect compressor 41 for compression and pressurization; S500: passing the heating steam and the concentrated liquid into a crystallization evaporator for evaporation and crystallization to obtain crystal slurry, secondary steam III and condensed water; Passing secondary steam II and secondary steam III into the compression mechanism; Specifically, the heating steam in the evaporation crystallization is the heating steam generated by the primary compressor 41, and the raw steam III is passed into the primary compressor 41 for compression and pressurization; S600: The crystal slurry is passed into the centrifugal salt outlet system 7 for treatment to obtain finished salt.

[0071] In summary, the ammonia nitrogen wastewater treatment method in the embodiment of the present invention is applied to the ammonia nitrogen wastewater treatment device, and an efficient steam circulation system can be constructed through the cooperation of the compression mechanism, the evaporation mechanism and the reboiler, ensuring that the steam can be efficiently recycled in the ammonia nitrogen wastewater treatment device, optimizing the process flow of ammonia nitrogen wastewater treatment, reducing the heat exchange frequency of the ammonia nitrogen wastewater treatment device, and improving the thermal energy utilization rate. At the same time, it also reduces the use of cooling water, reduces investment costs and electricity consumption, and solves the technical problems of the high cost of ammonia nitrogen wastewater treatment caused by the low efficiency of steam recycling in the prior art. And the ammonia nitrogen wastewater treatment device of this embodiment can operate normally whether it is in the case of large-flow wastewater treatment or small-flow wastewater treatment, with few restrictions and good applicability.

[0072] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0075] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. An ammonia nitrogen wastewater treatment device, characterized in that: The ammonia nitrogen wastewater treatment device comprises: A deammoniation tower (1), wherein the top of the deammoniation tower (1) is provided with an ammonia-containing steam outlet, and the bottom is provided with a deammoniation liquid outlet and a circulating heating liquid inlet; An evaporation mechanism, the evaporation mechanism comprising a primary evaporator (31), the primary evaporator (31) comprising a hot medium cavity I and a cold medium cavity I, the hot medium cavity I of the primary evaporator (31) comprising a hot medium cavity I inlet, a first hot medium cavity I outlet, and a second hot medium cavity I outlet, the cold medium cavity I of the primary evaporator (31) comprising a cold medium cavity I inlet, a first cold medium cavity I outlet, and a second cold medium cavity I outlet, the hot medium cavity I inlet of the primary evaporator (31) being connected to the ammonia-containing steam outlet of the deammonification tower (1), and the cold medium cavity I inlet of the primary evaporator (31) being connected to the deammoniation liquid outlet of the deammonification tower (1); A condenser (5), the condenser (5) comprising a hot medium cavity II and a cold medium cavity II, the hot medium cavity II of the condenser (5) comprising a first inlet of the hot medium cavity II, a second inlet of the hot medium cavity II, and a concentrated ammonia outlet, the cold medium cavity II of the condenser (5) comprising a cold medium cavity II inlet and a cold medium cavity II outlet, the first inlet of the hot medium cavity II of the condenser (5) being connected to the first outlet of the hot medium cavity I of the primary evaporator (31), and the second inlet of the hot medium cavity II of the condenser (5) being connected to the second outlet of the hot medium cavity I of the primary evaporator (31); A reboiler (2), the reboiler (2) comprising a hot medium cavity III and a cold medium cavity III, the hot medium cavity III of the reboiler (2) comprising a hot medium cavity III inlet and a hot medium cavity III outlet, the cold medium cavity III of the reboiler (2) comprising a cold medium cavity III inlet and a cold medium cavity III outlet, the hot medium cavity III inlet of the reboiler (2) being connected to the deammoniation liquid outlet of the deammoniation tower (1), and the cold medium cavity III outlet of the reboiler (2) being connected to the circulating heating liquid inlet of the deammoniation tower (1); A compression mechanism, the compression mechanism comprising a secondary steam inlet and a heating steam outlet, the secondary steam inlet of the compression mechanism being connected to the first outlet of the cold medium cavity I of the primary evaporator (31), and the heating steam outlet of the compression mechanism being connected to the inlet of the hot medium cavity III of the reboiler (2).

2. The ammonia nitrogen wastewater treatment device according to claim 1, characterized in that: The evaporation mechanism also includes a multi-effect evaporation group, which is used to evaporate and concentrate the liquid after the first-stage evaporation and generate secondary steam II. The multi-effect evaporation group includes a first inlet, a second inlet, a first outlet, a second outlet, and a condensed water outlet. The first inlet of the multi-effect evaporation group is connected to the heating steam outlet of the compression mechanism, the second inlet of the multi-effect evaporation group is connected to the second outlet of the cold medium cavity I of the first-stage evaporator, and the first outlet of the multi-effect evaporation group is connected to the secondary steam inlet of the compression mechanism.

3. The ammonia nitrogen wastewater treatment device according to claim 2, characterized in that: The ammonia nitrogen wastewater treatment device also includes a crystallization evaporator, which includes a first inlet, a second inlet, a first outlet, a second outlet, and a condensed water outlet. The first inlet of the crystallization evaporator is connected to the heating steam outlet of the compression mechanism, the second inlet of the crystallization evaporator is connected to the second outlet of the multi-effect evaporation group, and the first outlet of the crystallization evaporator is connected to the secondary steam inlet of the compression mechanism.

4. The ammonia nitrogen wastewater treatment device according to claim 3, characterized in that: The compression mechanism comprises a primary compressor (41) and a secondary compressor (42), wherein the primary compressor (41) is provided with a secondary steam inlet and a first heating steam outlet, and the secondary compressor (42) is provided with a steam inlet and a second heating steam outlet; The secondary steam inlet of the primary compressor (41) is connected to at least one of the first outlet of the cold medium cavity I of the primary evaporator (31), the first outlet of the multi-effect evaporation group, and the first outlet of the crystallization evaporator; The first heating steam outlet of the primary compressor (41) is connected to the steam inlet of the secondary compressor (42), the first inlet of the multi-effect evaporation group, and the first inlet of the crystallization evaporator; The second heating port of the secondary compressor (42) is connected to the inlet of the heat medium cavity III of the reboiler (2).

5. The ammonia nitrogen wastewater treatment device according to claim 2, characterized in that: The multi-effect evaporation group comprises a first-effect evaporator and a second-effect evaporator connected in series.

6. The ammonia nitrogen wastewater treatment device according to claim 4, characterized in that: The ammonia nitrogen wastewater treatment device also includes a condensate tank, the multiple-effect evaporation group is provided with a condensate outlet, and the condensate tank is connected to at least one of the condensate outlet of the multiple-effect evaporation group, the outlet of the heat medium cavity III of the reboiler (2), and the condensate outlet of the crystallization evaporator.

7. The ammonia nitrogen wastewater treatment device according to claim 3, characterized in that: The ammonia nitrogen wastewater treatment device further comprises a filter (6) arranged between the primary evaporator (31) and the multiple-effect evaporation group.

8. The ammonia nitrogen wastewater treatment device according to claim 1, characterized in that: The ammonia nitrogen wastewater treatment device also includes a preheating system (10).

9. A method for treating ammonia nitrogen wastewater, characterized in that: Applicable to the ammonia nitrogen wastewater treatment device according to any one of claims 1 to 8, the ammonia nitrogen wastewater treatment method comprises: S100: passing the ammonia nitrogen wastewater into the deammoniation tower (1) for gas-liquid separation pretreatment to obtain deammoniation liquid and ammonia-containing vapor; S200: passing the ammonia-containing steam into the heat medium cavity I of the primary evaporator (31) for preliminary condensation to obtain high-ammonia steam and condensed water; Passing a portion of the deammoniation liquid into the cold medium cavity I of the primary evaporator (31) to perform primary evaporation to obtain primary evaporated liquid and secondary steam I; Passing the secondary steam I into the compression mechanism to compress and pressurize the secondary steam I to obtain heating steam; Passing another portion of the deammoniation liquid into the cold medium cavity III of the reboiler (2), and passing heating steam into the hot medium cavity III of the reboiler (2) to obtain condensed water; S300: The high ammonia vapor is passed into the heat medium cavity II of the condenser (5) and subjected to secondary condensation with cooling water to obtain concentrated ammonia water.

10. The method for treating ammonia nitrogen wastewater according to claim 9, characterized in that: The ammonia nitrogen wastewater treatment method also includes: S400: passing the heating steam and the liquid after the primary evaporation into a multiple-effect evaporation group to obtain a concentrated liquid, secondary steam II and condensed water; S500: passing the heating steam and the concentrated liquid into a crystallization evaporator for evaporation and crystallization to obtain crystal slurry, secondary steam III and condensed water; Passing the secondary steam II and the secondary steam III into the compression mechanism; S600: The slurry is passed into a centrifugal salt extraction system (7) for processing to obtain finished salt.

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