A pre-alkalization vacuum stripping ammonia removal system

Abstract

The present application relates to the technical field of ammonia-containing waste liquid treatment, and specifically discloses a pre-alkalization negative pressure stripping ammonia removal system, which comprises a pipeline mixer configured to input ammonia-containing waste liquid and liquid alkali; a pH adjusting tank, an inlet of which is communicated with an outlet of the pipeline mixer; a heat exchanger, a first inlet of which is communicated with an outlet of the pH adjusting tank, and a first outlet of the heat exchanger is used for discharging ammonia removal tail liquid; a negative pressure stripping ammonia removal tower, a first inlet of which is communicated with a second outlet of the heat exchanger, and a first outlet of the negative pressure stripping ammonia removal tower is communicated with a second inlet of the heat exchanger; a gas-liquid separator, an inlet of which is communicated with a second outlet of the negative pressure stripping ammonia removal tower, and a first outlet of the gas-liquid separator is communicated with a second inlet of the negative pressure stripping ammonia removal tower; and a circulating unit, an inlet of which is communicated with a second outlet of the gas-liquid separator. The pre-alkalization negative pressure stripping ammonia removal system of the present application reduces the energy consumption of treatment and obtains ammonia water with higher purity.

Description

Technical Field

[0001] This invention relates to the field of ammonia-containing wastewater treatment technology, and in particular to a pre-alkalization negative pressure stripping ammonia removal system. Background Technology

[0002] Chemical production processes generate ammonia nitrogen wastewater. Direct discharge not only exacerbates eutrophication of water bodies but also increases the difficulty and cost of water treatment, and may even have toxic effects on organisms and human health. Therefore, effective treatment is necessary before discharge. Currently, steam stripping deammoniation technology is widely used in the treatment of medium- and high-concentration ammonia nitrogen wastewater.

[0003] However, existing stripping ammonia removal systems generally suffer from high energy consumption. Taking, for example, a stripping ammonia removal system for ammonia nitrogen wastewater treatment described in Chinese invention patent CN119750688A, requires a continuous supply of fresh steam during the stripping process, supplemented by a steam compressor to recover some secondary steam. However, due to the temperature difference between the fresh steam and the recovered steam, if they are not fully mixed before being introduced into the distillation column, it easily leads to uneven temperature distribution within the column. This not only affects mass transfer efficiency but also forces the rising steam to travel a long distance within the column to heat the trays and preheat the wastewater, resulting in a significant increase in steam heat consumption. This necessitates increasing the initial steam supply to maintain the final ammonia removal effect, thus keeping overall energy consumption high. Furthermore, under conditions of uneven steam mixing and temperature gradients, existing stripping ammonia removal systems often carry a large amount of water vapor and impurities in the tail gas after ammonia removal, resulting in low purity of the recovered ammonia water. This makes it difficult to directly reuse or utilize it at higher values, reducing the economic added value of the byproduct. Summary of the Invention

[0004] The purpose of this invention is to provide a pre-alkalization negative pressure stripping ammonia removal system that reduces processing energy consumption and obtains higher purity ammonia water.

[0005] To achieve the above objectives, the present invention provides a pre-alkalization negative pressure stripping ammonia removal system, comprising: The pipeline mixer is configured to receive ammonia-containing waste liquid and liquid alkali; pH adjustment tank, the inlet of which is connected to the outlet of the pipeline mixer; A heat exchanger, the first inlet of which is connected to the outlet of the pH adjustment tank, and the first outlet of the heat exchanger is used to discharge the deammoniation tail liquid; The negative pressure stripping ammonia removal tower has its first inlet connected to the second outlet of the heat exchanger, and the first outlet of the negative pressure stripping ammonia removal tower is connected to the second inlet of the heat exchanger. A gas-liquid separator, the inlet of which is connected to the second outlet of the negative pressure stripping ammonia removal tower, and the first outlet of the gas-liquid separator being connected to the second inlet of the negative pressure stripping ammonia removal tower; and The circulation unit has its inlet connected to the second outlet of the gas-liquid separator.

[0006] In some embodiments, the circulation unit includes a circulation tower, a vacuum pump, a cooler, and a circulation pump. The first inlet of the vacuum pump is connected to the second outlet of the gas-liquid separator, the second inlet of the vacuum pump is connected to the outlet of the cooler, the outlet of the vacuum pump is connected to the first inlet of the circulation tower, and the inlet of the cooler is connected to the first outlet of the circulation tower.

[0007] In some embodiments, the circulation unit further includes a pure water pipeline and a pure water valve installed on the pure water pipeline, the outlet of the pure water pipeline being connected to the second inlet of the circulation tower.

[0008] In some embodiments, the circulation unit further includes an ammonia water pipeline, an ammonia water pump, an ammonia water concentration meter, and an ammonia water valve sequentially installed on the ammonia water pipeline, wherein the inlet of the ammonia water pipeline is connected to the second outlet of the circulation tower.

[0009] In some embodiments, the circulation unit further includes a reflux pipeline and a reflux valve installed on the reflux pipeline, the outlet of the reflux pipeline being connected to the third inlet of the circulation tower, and the outlet of the reflux pipeline being connected to the ammonia pipeline between the ammonia concentration meter and the ammonia valve.

[0010] In some embodiments, the system includes a wastewater transfer pump, a first flow meter, a liquid alkali transfer pump, and a second flow meter. The wastewater transfer pump is connected to a first inlet of the pipeline mixer via the first flow meter, and the liquid alkali transfer pump is connected to a second inlet of the pipeline mixer via the second flow meter.

[0011] In some embodiments, the pH adjusting tank is equipped with a pH sensor.

[0012] In some embodiments, the pre-alkalization negative pressure stripping ammonia removal system further includes a reboiler for heating the negative pressure stripping ammonia removal tower.

[0013] In some embodiments, the reboiler inlet is provided with a steam regulating valve, and the negative pressure stripping ammonia removal tower is provided with a temperature sensor and a liquid level sensor.

[0014] In some embodiments, the second outlet of the gas-liquid separator is provided with an ammonia temperature sensor and an ammonia pressure gauge.

[0015] This invention provides a pre-alkalization negative pressure stripping ammonia removal system, which has the following advantages compared with the prior art: By combining a pipeline mixer with a pH adjustment tank, pre-alkalization treatment is completed before the ammonia-containing waste liquid enters the negative pressure stripping ammonia removal tower, which fully converts ammonium ions in the ammonia-containing waste liquid into free ammonia molecules, which is beneficial for subsequent ammonia removal. The gas-liquid separator separates the ammonia-containing gas output from the negative pressure stripping ammonia removal tower into gas and liquid. The separated ammonia gas is recovered by the circulation unit, avoiding water vapor and impurities from mixing into the ammonia water, thereby obtaining ammonia water with higher purity and improving the resource utilization value. At the same time, the first outlet of the gas-liquid separator returns the separated liquid to the negative pressure stripping ammonia removal tower, realizing a closed-loop circulation of materials within the system and improving utilization rate. The negative pressure stripping ammonia removal tower lowers the boiling point of the liquid under negative pressure conditions, which can effectively utilize low-grade heat sources, thereby reducing processing energy consumption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a pre-alkalization negative pressure stripping ammonia removal system provided for some embodiments of the present invention.

[0017] In the diagram: 100. Pre-alkalization negative pressure stripping ammonia removal system; 1. Pipeline mixer; 2. pH adjustment tank; 21. pH sensor; 3. Heat exchanger; 4. Negative pressure stripping ammonia removal tower; 41. Temperature sensor; 42. Liquid level sensor; 5. Gas-liquid separator; 51. Ammonia temperature sensor; 52. Ammonia pressure gauge; 6. Circulation unit; 61. Circulation tower; 62. Vacuum pump; 63. Cooler; 64. Circulation pump; 65. Pure water pipeline; 66. Pure water valve; 67. Ammonia pipeline; 671. Ammonia pump; 672. Ammonia concentration meter; 673. Ammonia valve; 68. Return pipeline; 681. Return valve; 7. Wastewater transfer pump; 71. First flow meter; 8. Liquid alkali transfer pump; 81. Second flow meter; 9. Reboiler; 91. Steam regulating valve. Detailed Implementation

[0018] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0019] It should be understood that in the description of this application, the terms "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. That is, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, unless otherwise stated, "a plurality of" means two or more.

[0020] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0021] like Figure 1 As shown, the pre-alkalization negative pressure stripping ammonia removal system 100 provided in this embodiment of the invention includes a pipeline mixer 1, a pH adjustment tank 2, a heat exchanger 3, a negative pressure stripping ammonia removal tower 4, a gas-liquid separator 5, and a circulation unit 6.

[0022] Pipeline mixer 1 is configured to receive ammonia-containing waste liquid and liquid alkali. After initial mixing within pipeline mixer 1, the mixture is discharged from the outlet of pipeline mixer 1.

[0023] The inlet of pH adjusting tank 2 is connected to the outlet of pipeline mixer 1. The mixed liquid enters pH adjusting tank 2 to adjust the pH value, so that the ammonium ions in the ammonia-containing waste liquid are fully converted into free ammonia molecules, providing favorable chemical conditions for subsequent stripping and deammoniation.

[0024] The first inlet of heat exchanger 3 is connected to the outlet of pH adjustment tank 2. The waste liquid after pH adjustment tank 2 enters heat exchanger 3 for preheating. The first outlet of heat exchanger 3 is used to discharge the deammoniation tail liquid. The tail liquid after deammoniation treatment is discharged from the system after heat exchanger 3 for heat exchange and cooling.

[0025] The first inlet of the negative pressure stripping ammonia removal tower 4 is connected to the second outlet of the heat exchanger 3. The waste liquid, after being preheated by the heat exchanger 3, enters the negative pressure stripping ammonia removal tower 4 for negative pressure stripping ammonia removal treatment. The first outlet of the negative pressure stripping ammonia removal tower 4 is connected to the second inlet of the heat exchanger 3. The ammonia-containing hot gas output from the negative pressure stripping ammonia removal tower 4 exchanges heat with the cold waste liquid entering the heat exchanger 3, realizing the cascade recovery and utilization of heat in the negative pressure stripping ammonia removal tower 4.

[0026] The inlet of the gas-liquid separator 5 is connected to the second outlet of the negative pressure stripping ammonia removal tower 4. The ammonia-containing gas output from the negative pressure stripping ammonia removal tower 4 enters the gas-liquid separator 5 for gas-liquid separation. The first outlet of the gas-liquid separator 5 is connected to the second inlet of the negative pressure stripping ammonia removal tower 4. The liquid separated in the gas-liquid separator 5 flows back to the negative pressure stripping ammonia removal tower 4 through the first outlet, realizing a closed-loop circulation of materials within the system and improving material utilization.

[0027] The inlet of the circulation unit 6 is connected to the second outlet of the gas-liquid separator 5. The ammonia-containing gas separated by the gas-liquid separator 5 enters the circulation unit 6 through the second outlet for recycling to obtain ammonia water with higher purity.

[0028] Based on the above structural setup, the pre-alkalization treatment is completed before the ammonia-containing waste liquid enters the negative pressure stripping ammonia removal tower 4 through the cooperation of the pipeline mixer 1 and the pH adjustment tank 2. This ensures that the ammonium ions in the ammonia-containing waste liquid are fully converted into free ammonia molecules, which is beneficial for subsequent ammonia removal. The gas-liquid separator 5 separates the ammonia-containing gas output from the negative pressure stripping ammonia removal tower 4. The separated ammonia gas is recovered by the circulation unit 6, avoiding the mixing of water vapor and impurities into the ammonia water, thereby obtaining ammonia water with higher purity and improving the resource utilization value. At the same time, the first outlet of the gas-liquid separator 5 returns the separated liquid to the negative pressure stripping ammonia removal tower 4, realizing a closed-loop circulation of materials within the system and improving utilization rate. The negative pressure stripping ammonia removal tower 4 lowers the boiling point of the liquid under negative pressure conditions, which can effectively utilize low-grade heat sources, thereby reducing processing energy consumption.

[0029] like Figure 1 As shown, in some embodiments, the circulation unit 6 includes a circulation tower 61, a vacuum pump 62, a cooler 63, and a circulation pump 64. The first inlet of the vacuum pump 62 is connected to the second outlet of the gas-liquid separator 5, the second inlet of the vacuum pump 62 is connected to the outlet of the cooler 63, the outlet of the vacuum pump 62 is connected to the first inlet of the circulation tower 61, and the inlet of the cooler 63 is connected to the first outlet of the circulation tower 61. The ammonia-containing gas separated by the gas-liquid separator 5 is pumped to the circulation tower 61 by the vacuum pump 62. After being cooled by the cooler 63, part of the ammonia-containing gas in the circulation tower 61 flows back to the second inlet of the vacuum pump 62, mixes with the ammonia-containing gas output from the gas-liquid separator 5, and then re-enters the circulation tower 61, forming a circulating absorption loop and improving the ammonia absorption efficiency.

[0030] like Figure 1 As shown, in some embodiments, the circulation unit 6 further includes a pure water pipeline 65 and a pure water valve 66 installed on the pure water pipeline 65. The outlet of the pure water pipeline 65 is connected to the second inlet of the circulation tower 61. Pure water is supplied to the circulation tower 61 through the pure water pipeline 65 to absorb ammonia-containing gas and form ammonia water. The pure water valve 66 is used to control the supply of pure water.

[0031] like Figure 1As shown, in some embodiments, the circulation unit 6 further includes an ammonia water pipeline 67, an ammonia water pump 671, an ammonia water concentration meter 672, and an ammonia water valve 673 sequentially installed on the ammonia water pipeline 67. The inlet of the ammonia water pipeline 67 is connected to the second outlet of the circulation tower 61. The ammonia water formed in the circulation tower 61 is discharged through the ammonia water pipeline 67. The ammonia water pump 671 provides power for the ammonia water output, the ammonia water concentration meter 672 monitors the concentration of the output ammonia water in real time, and the ammonia water valve 673 is used to control the on / off state of the ammonia water output.

[0032] like Figure 1 As shown, in some embodiments, the circulation unit 6 further includes a reflux pipeline 68 and a reflux valve 681 installed on the reflux pipeline 68. The outlet of the reflux pipeline 68 is connected to the third inlet of the circulation tower 61, and the outlet of the reflux pipeline 68 is connected to the ammonia pipeline 67 between the ammonia concentration meter 672 and the ammonia valve 673. When the ammonia concentration meter 672 detects that the ammonia concentration has not reached the set value, the reflux valve 681 can be opened to allow the substandard ammonia to return to the circulation tower 61 through the reflux pipeline 68 for continued circulation and absorption until the ammonia concentration reaches the required level. Then, the ammonia valve 673 is opened to discharge the ammonia, thereby ensuring the purity of the output ammonia.

[0033] like Figure 1 As shown, in some embodiments, the system includes a wastewater transfer pump 7, a first flow meter 71, a liquid alkali transfer pump 8, and a second flow meter 81. The wastewater transfer pump 7 is connected to the first inlet of the pipeline mixer 1 via the first flow meter 71, and the liquid alkali transfer pump 8 is connected to the second inlet of the pipeline mixer 1 via the second flow meter 81. The wastewater transfer pump 7 is used to transport ammonia-containing wastewater to the pipeline mixer 1, and the first flow meter 71 is used to monitor the input flow rate of the ammonia-containing wastewater in real time. The liquid alkali transfer pump 8 is used to transport liquid alkali to the pipeline mixer 1, and the second flow meter 81 is used to monitor the input flow rate of the liquid alkali in real time. Through the cooperation of the first flow meter 71 and the second flow meter 81, the mixing ratio of ammonia-containing wastewater and liquid alkali can be precisely controlled, ensuring the stability of the pre-alkalization effect.

[0034] like Figure 1 As shown, in some embodiments, the pH adjusting tank 2 is equipped with a pH sensor 21. The pH sensor 21 is used to monitor the pH value of the mixture in the pH adjusting tank 2 in real time, so as to adjust the dosage of liquid alkali in a timely manner according to the monitoring results, and ensure that the pH value of the mixture is maintained within the set range, thus creating conditions for subsequent negative pressure stripping and ammonia removal.

[0035] like Figure 1 As shown, in some embodiments, the pre-alkalization negative pressure stripping ammonia removal system 100 further includes a reboiler 9, which is used to heat the negative pressure stripping ammonia removal tower 4. The reboiler 9 provides heat to the negative pressure stripping ammonia removal tower 4, maintains the temperature conditions required for negative pressure stripping within the negative pressure stripping ammonia removal tower 4, and ensures the continuous progress of the stripping ammonia removal reaction.

[0036] like Figure 1 As shown, in some embodiments, a steam regulating valve 91 is installed at the inlet of the reboiler 9, and a temperature sensor 41 and a liquid level sensor 42 are installed in the negative pressure stripping ammonia removal tower 4. The steam regulating valve 91 is used to regulate the amount of heating steam entering the reboiler 9, the temperature sensor 41 is used to monitor the temperature inside the negative pressure stripping ammonia removal tower 4 in real time, and the liquid level sensor 42 is used to monitor the liquid level inside the negative pressure stripping ammonia removal tower 4 in real time. Through the cooperation of the temperature sensor 41 and the steam regulating valve 91, precise control of the temperature inside the negative pressure stripping ammonia removal tower 4 can be achieved; through the liquid level sensor 42, the liquid level inside the negative pressure stripping ammonia removal tower 4 can be monitored in real time, ensuring the stability and safety of the system operation.

[0037] like Figure 1 As shown, in some embodiments, the second outlet of the gas-liquid separator 5 is equipped with an ammonia temperature sensor 51 and an ammonia pressure gauge 52. The ammonia temperature sensor 51 is used to monitor the temperature of the ammonia output from the gas-liquid separator 5 in real time, and the ammonia pressure gauge 52 is used to monitor the pressure of the ammonia output from the gas-liquid separator 5 in real time, providing a basis for the adjustment of the operating parameters of the circulation unit 6.

[0038] Based on the above embodiments, the control flow of the pre-alkalization negative pressure stripping ammonia removal system 100 of the present invention is as follows: I. Parameter Initialization and Proportion Calculation: Before system operation, the operator enters the ammonium concentration of the ammonia-containing waste liquid and the mass percentage concentration of the added liquid alkali into the control system. Based on the stoichiometric formula for the neutralization reaction of diammonium salts, the control system automatically calculates the standard flow ratio coefficient of the waste liquid and liquid alkali, which serves as the benchmark value for subsequent adjustments.

[0039] II. Ammonia-containing wastewater flow rate acquisition and dynamic alkali mixing: The ammonia-containing wastewater is delivered at a constant rate by a wastewater transfer pump, and the first flow meter collects the fluctuation data of the ammonia-containing wastewater flow rate in real time. The control system calculates the real-time flow rate with the preset mixing ratio coefficient, dynamically generates the set flow rate value of the alkali solution, and controls the alkali transfer pump to adaptively adjust the frequency and add alkali, ensuring that the mixing ratio of the two media is accurately locked.

[0040] 3. Liquid alkali flow rate PID closed-loop correction: The second flow meter feeds back the actual alkali flow rate to the control system in real time. The PID controller dynamically compares the deviation between the set value and the actual value and makes a slight correction to the frequency of the liquid alkali delivery pump. It accurately compensates for the mixing error caused by factors such as pipeline resistance, pump efficiency and power frequency fluctuation, ensuring accurate mixing without oscillation.

[0041] IV. Independent pH Monitoring and Traceability: A pH sensor installed on the pH adjustment tank continuously monitors the pH value of the mixed solution. This pH data is used only for operation recording and abnormal operating condition alarms, and does not participate in the real-time adjustment of the alkali addition amount, thereby avoiding the control defects caused by lag adjustment and ensuring rapid response.

[0042] V. Closed-loop flow stabilization before the tower: Before the ammonia-containing waste liquid enters the negative pressure stripping ammonia removal tower, a flow meter and an electric regulating valve are installed before the tower to form a PID closed-loop control loop, which eliminates disturbances in the feed flow in real time, ensures that the feed load entering the negative pressure stripping ammonia removal tower is constant, and creates stable feed conditions for subsequent negative pressure stripping.

[0043] VI. Tower Temperature and Dual-Level PID Steady-State Control: The PID controller precisely adjusts the opening of the reboiler inlet steam regulating valve according to the set value, stably controlling the bottom temperature of the tower at 80℃ and the top temperature at 60℃, maintaining constant temperature ammonia removal conditions; at the same time, the dual-level PID linkage control of the negative pressure stripping ammonia removal tower and the gas-liquid separator balances the distillation reflux flow rate and the gas-liquid separation rate, comprehensively ensuring the steady-state operation of the working conditions.

[0044] VII. Top-of-Column Total Reflux Distillation Purification and Tail Gas Absorption: High-concentration ammonia vapor output from the top of the negative pressure stripping ammonia removal column is collected in the gas-liquid separator. Considering the potential for liquid entrainment and high impurity levels in the ammonia solution formed during the initial condensation, all the low-quality ammonia solution in the gas-liquid separator is refluxed to the top of the negative pressure stripping ammonia removal column as distillation reflux liquid to enhance the mass transfer purification process, continuously enrich ammonia gas, and remove impurities. The uncondensed residual ammonia gas is extracted under negative pressure by a vacuum pump and sent to a circulating column for absorption by pure water circulation spraying to prepare high-purity ammonia solution.

[0045] 8. Ammonia Concentration Judgment and Adaptive External Discharge Water Replenishment: After multiple reflux purification processes, the ammonia water in the circulating tower undergoes normal circulation and homogenization through ammonia water pipelines, reflux pipelines, and ammonia water pumps. An ammonia concentration meter installed on the ammonia water pipelines monitors the concentration in real time. When the detected concentration reaches the set qualified threshold, the control system automatically switches valve groups, closing the reflux valve and opening the ammonia water valve to complete the external discharge and collection of qualified ammonia water. When the liquid level in the circulating tower drops to the shutdown threshold, the control system automatically shuts down the ammonia water pump and resets the reflux operation. Simultaneously, it opens the pure water valve, replenishing water to the circulating tower through the pure water pipeline until the normal operating level is reached before resetting and shutting down, achieving fully automatic circulating purification, sorting, and recovery.

[0046] The process flow of the pre-alkalization negative pressure stripping ammonia removal system 100 of the present invention is as follows: After the pre-alkalization negative pressure stripping ammonia removal system is fully automated and continuous after commissioning, it achieves 100% commissioning. Taking high-salt wastewater containing ammonium nitrate and ammonium chloride as an example, the ammonia-containing wastewater is delivered at a constant flow rate by the wastewater transfer pump. Based on real-time flow and concentration parameters, the liquid alkali transfer pump precisely controls the addition of 48% liquid alkali according to the stoichiometric ratio. After the two media are homogenized and mixed by the pipeline mixer, the pH value of the wastewater is raised to above 12, ensuring that ammonium ions are fully converted into free ammonia. The mixed liquid enters the pH adjustment tank for buffering and pressure stabilization, and after completing the operating condition monitoring, it is sent to the negative pressure stripping ammonia removal tower at a constant flow rate.

[0047] The negative pressure stripping ammonia removal tower completes ammonia removal under constant temperature conditions. Ammonia vapor at the top of the tower is condensed and purified by total reflux distillation, and high-quality ammonia water is produced through vacuum tail gas absorption. The entire process is automatically controlled, including the discharge of qualified ammonia water, the recirculation of unqualified ammonia water, and water replenishment linked to liquid level, based on concentration discrimination. The ammonia nitrogen concentration at the bottom of the tower is consistently below 10 mg / L. The ammonia removal tail liquid is discharged through the first outlet of the heat exchanger and can be adjusted to neutral with mixed acid as needed before being sent to the evaporation and crystallization unit for salt separation and reuse of production water.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A pre-alkalization negative pressure stripping ammonia removal system, characterized in that, include: The pipeline mixer is configured to receive ammonia-containing waste liquid and liquid alkali; pH adjustment tank, the inlet of which is connected to the outlet of the pipeline mixer; A heat exchanger, the first inlet of which is connected to the outlet of the pH adjustment tank, and the first outlet of the heat exchanger is used to discharge the deammoniation tail liquid; The negative pressure stripping ammonia removal tower has its first inlet connected to the second outlet of the heat exchanger, and the first outlet of the negative pressure stripping ammonia removal tower is connected to the second inlet of the heat exchanger. A gas-liquid separator, the inlet of which is connected to the second outlet of the negative pressure stripping ammonia removal tower, and the first outlet of the gas-liquid separator being connected to the second inlet of the negative pressure stripping ammonia removal tower; and The circulation unit has its inlet connected to the second outlet of the gas-liquid separator.

2. The pre-alkalization negative pressure stripping ammonia removal system according to claim 1, characterized in that, The circulation unit includes a circulation tower, a vacuum pump, a cooler, and a circulation pump. The first inlet of the vacuum pump is connected to the second outlet of the gas-liquid separator, the second inlet of the vacuum pump is connected to the outlet of the cooler, the outlet of the vacuum pump is connected to the first inlet of the circulation tower, and the inlet of the cooler is connected to the first outlet of the circulation tower.

3. The pre-alkalization negative pressure stripping ammonia removal system according to claim 2, characterized in that, The circulation unit also includes a pure water pipeline and a pure water valve installed on the pure water pipeline, and the outlet of the pure water pipeline is connected to the second inlet of the circulation tower.

4. The pre-alkalization negative pressure stripping ammonia removal system according to claim 2, characterized in that, The circulation unit also includes an ammonia water pipeline, an ammonia water pump, an ammonia water concentration meter, and an ammonia water valve installed sequentially on the ammonia water pipeline, and the inlet of the ammonia water pipeline is connected to the second outlet of the circulation tower.

5. The pre-alkalization negative pressure stripping ammonia removal system according to claim 4, characterized in that, The circulation unit further includes a reflux pipeline and a reflux valve installed on the reflux pipeline. The outlet of the reflux pipeline is connected to the third inlet of the circulation tower, and the outlet of the reflux pipeline is connected to the ammonia pipeline between the ammonia concentration meter and the ammonia valve.

6. The pre-alkalization negative pressure stripping ammonia removal system according to claim 1, characterized in that, It includes a wastewater transfer pump, a first flow meter, a liquid alkali transfer pump, and a second flow meter. The wastewater transfer pump is connected to the first inlet of the pipeline mixer through the first flow meter, and the liquid alkali transfer pump is connected to the second inlet of the pipeline mixer through the second flow meter.

7. The pre-alkalization negative pressure stripping ammonia removal system according to claim 1, characterized in that, The pH adjustment tank is equipped with a pH sensor.

8. The pre-alkalization negative pressure stripping ammonia removal system according to claim 1, characterized in that, The pre-alkalization negative pressure stripping ammonia removal system also includes a reboiler, which is used to heat the negative pressure stripping ammonia removal tower.

9. The pre-alkalization negative pressure stripping ammonia removal system according to claim 8, characterized in that, The reboiler inlet is equipped with a steam regulating valve, and the negative pressure stripping ammonia removal tower is equipped with a temperature sensor and a liquid level sensor.

10. The pre-alkalization negative pressure stripping ammonia removal system according to claim 1, characterized in that, The second outlet of the gas-liquid separator is equipped with an ammonia temperature sensor and an ammonia pressure gauge.

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