Diluted ammonia water concentration device

Abstract

The utility model discloses a dilute ammonia water concentration device which comprises a stripping tower, a stripping tower condenser positioned at the top of the stripping tower and communicated with the stripping tower, and an absorption tower connected with the stripping tower condenser, the stripping tower condenser comprises a gas phase outlet arranged at the top and a liquid phase outlet arranged at the bottom, the liquid-phase outlet is connected with a liquid-phase inlet in the upper part of the absorption tower through a pipeline; and a gas phase outlet at the top of the stripping tower condenser is connected with a gas phase inlet at the lower part of the absorption tower sequentially through a vacuum buffer tank and a vacuum pump by virtue of a pipeline. The device is short in process, simple in equipment structure, green, energy-saving, safe, environment-friendly and wide in practicability; the height difference between the outlet of the condenser of the stripping tower and the inlet of the absorbent of the absorption tower is utilized, so that the absorbent can flow into the absorption tower from the condenser through gravity flow, the arrangement of a pump is reduced, and the total energy consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the field of resource utilization of ammonia-containing wastewater, in particular to a device for concentrating dilute ammonia water. Background Art

[0002] Ammonia is an inorganic compound with the chemical formula NH3 and a molecular weight of 17.031. Under standard conditions, the density is 0.771 g / L and the relative density is 0.5971 (air = 1.00). It is a colorless gas with a strong pungent odor. Ammonia is easily soluble in water and can produce a small amount of hydroxide ions in water, which is weakly alkaline. Ammonia is widely used in chemical production processes. Many chemical processes involve ammonia and ammonia water. For example, in the production of ammonium chloride, the evaporation and crystallization of ammonium chloride solution not only produces ammonium chloride products, but also produces a large amount of ammonia-containing evaporated condensed water. Since the evaporated condensed water contains 3-4 g / L of ammonia (in the form of free ammonia), it affects the subsequent comprehensive utilization and cannot be discharged directly.

[0003] In the traditional process, the water vapor and ammonia mixed gas evaporated from the top of the stripping tower is condensed in the condenser, and the condensate is fully refluxed. The ammonia containing a small amount of water is sent from the top of the condenser to the downstream absorption tower to be absorbed by fresh water to produce qualified concentrated ammonia product.

[0004] Although the traditional process can solve the demand for ammonia recovery, it has the following technical problems:

[0005] 1) Ammonia evaporation process, a commonly used process requires the addition of alkali (such as sodium hydroxide). Since the water after ammonia extraction is to be recycled as recycled water, other substances cannot be introduced into the system. Therefore, the process of adding alkali to evaporate ammonia is not applicable.

[0006] 2) The traditional ammonia concentration process without adding alkali first separates ammonia from dilute ammonia by steam stripping, and then uses fresh water to absorb the separated ammonia. Ammonia undergoes a process of first concentration and then dilution, resulting in a waste of energy.

[0007] 3) Traditional processes require fresh water to produce concentrated ammonia products, but there is a large amount of available water in the dilute ammonia used as raw material. Adding fresh water during the ammonia production process will increase water consumption and wastewater discharge.

[0008] 4) In the traditional process, the liquid material in the absorption tower needs to be fed by a pump, which consumes electricity. Utility Model Content

[0009] The utility model aims to develop a dilute ammonia water concentration device with a short process flow, simple equipment structure, green energy saving, safety and environmental protection, wide practicability, and can use various heat sources such as hot water and steam. The utility model can be applied to various occasions where clean dilute ammonia water needs to be concentrated to produce ammonia water above 20%wt.

[0010] The utility model discloses a dilute ammonia water concentration device, which comprises a stripping tower, a stripping tower condenser located at the top of the stripping tower and connected to the stripping tower, and an absorption tower connected to the stripping tower condenser. The stripping tower condenser comprises a gas phase outlet arranged at the top and a liquid phase outlet arranged at the bottom, and the liquid phase outlet is connected to a liquid phase inlet at the upper part of the absorption tower through a pipeline; the gas phase outlet at the top of the stripping tower condenser is connected to the gas phase inlet at the lower part of the absorption tower through a pipeline in sequence through a vacuum buffer tank and a vacuum pump, the liquid phase outlet of the stripping tower condenser is higher than the liquid phase inlet at the top of the absorption tower, the absorption tower kettle is connected to an absorption tower circulating pump, the absorption tower circulating pump outlet is connected to an absorption tower cooler, one outlet of the absorption tower cooler is divided into two streams, one stream is connected to the absorption tower, and the other stream is used as a concentrated ammonia water finished product out-of-bounds area, the stripping tower kettle is connected to a recycled water pump, and a tail gas fan is arranged at the top of the absorption tower.

[0011] As a further improvement, the stripping tower condenser described in the utility model is directly connected to the stripping tower through an equipment flange, the dilute ammonia water feed port of the stripping tower is located in the middle of the tower, the heat source feed port is connected to the tower kettle, the dilute ammonia water feed port is above the distillation section, and the feed port is below the stripping section. The packing type of the stripping tower is random packing or structured packing, the packing height of the distillation section is 0.3-1.5m, the packing height of the stripping section is 4-10m, the skirt height is 5-8m, and the whole tower height is 17-25m. According to the concentration of the feed dilute ammonia water, the ratio of the stripping section to the distillation section tower diameter of the stripping tower is between 3.0 and 0.9.

[0012] As a further improvement, a liquid collecting weir is provided at the bottom of the lower part of the stripping tower condenser described in the utility model, and the liquid phase outlet of the stripping tower condenser is arranged on the side of the liquid collecting weir. The height of the liquid phase outlet is lower than the weir height of the liquid collecting weir. Part of the condensate condensed by the stripping tower condenser is discharged from the liquid phase discharge port to the absorption tower, and the other part overflows from the top of the collecting weir and refluxes into the stripping tower.

[0013] As a further improvement, the absorption tower described in the utility model is a packed tower, and its packing type is random packing or structured packing, the packing height is 1 to 4 meters, the whole tower height is 5 to 9 meters, and the height difference between the liquid phase outlet of the stripping tower condenser and the liquid phase inlet of the absorption tower is 8 to 20 meters. The liquid phase condensed by the stripping tower condenser can enter the liquid phase inlet at the top of the stripping tower through the gravity flow.

[0014] As a further improvement, the temperature of the dilute ammonia water to be treated sent from the upstream device instead of circulating water in the cold side of the absorption tower cooler described in the utility model is lower than or equal to 32°C, and the dilute ammonia water after heat exchange still enters the middle part of the stripping tower.

[0015] The beneficial effects of the utility model are as follows:

[0016] 1) In the process of manufacturing finished ammonia water, the utility model device utilizes the condensate of the stripping tower condenser to absorb the stripping tower condenser. No fresh water needs to be added during the entire process, which reduces water consumption and wastewater discharge.

[0017] 2) The utility model device makes full use of the height difference between the outlet of the stripping tower condenser and the inlet of the absorbent in the absorption tower, so that the absorbent can flow from the condenser into the absorption tower through gravity flow, reducing the setting of the machine pump and reducing the overall energy consumption. The utility model adopts vacuum stripping to extract ammonia gas and low-concentration ammonia water, and vacuum stripping is more efficient than atmospheric pressure stripping in extracting ammonia.

[0018] Since the utility model needs to process an ammonia-water system, the utility model uses steam and hot water to directly exchange heat with the stripping tower feed, thereby saving the equipment investment of the heat exchanger.

[0019] Further technical features of the utility model

[0020] (1) A direct-connected condenser is used at the top of the stripping tower, which fully utilizes the height of the stripping tower so that the liquid phase discharge from the stripping tower can enter the absorption tower through gravity flow, saving the investment in equipment such as pumps and intermediate tanks. On the other hand, since the stripping tower adopts a direct-connected condenser, all equipment in this embodiment can be arranged in the ±0 plane, eliminating the investment in building a steel platform. The equipment layout of this embodiment occupies a small area of ​​only 11×5m.

[0021] (2) Since the device needs to treat an ammonia-water system, the present embodiment uses steam and hot water to directly exchange heat with the stripping tower feed, thus eliminating the equipment investment in a heat exchanger.

[0022] (3) This embodiment has a small number of equipment and a short process flow. It is estimated that the total equipment investment is only about 600,000 yuan.

[0023] (4) The utility steam and other engineering consumption in this embodiment is low. It is estimated that the operating cost of the device is about 830.9 yuan per ton of concentrated ammonia water, which is basically the same as the selling price of ammonia water. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is the utility model of dilute ammonia water concentration device and process diagram:

[0025] Figure 2It is a relationship diagram between the "reflux ratio" of the stripping tower in the utility model and the "sum of the ammonia content in the non-condensable vapor phase discharge and the condensate liquid phase discharge at the top of the stripping tower".

[0026] In the figure: 1-stripping tower; 2-stripping tower condenser; 3-vacuum buffer tank; 4-vacuum pump; 5-absorption tower; 6-exhaust gas fan; 7-absorption tower circulation pump; 8-absorption tower cooler; 9-recycled water pump. DETAILED DESCRIPTION

[0027] The technical solution of the utility model is further described below by means of specific embodiments in conjunction with the accompanying drawings of the specification:

[0028] Figure 1 The utility model discloses a dilute ammonia water concentration device and a process diagram. The utility model discloses a dilute ammonia water concentration device, which comprises a stripping tower 1, a stripping tower condenser 2 located at the top of the stripping tower 1 and connected to the stripping tower 1, and an absorption tower 5 connected to the stripping tower condenser 2. The stripping tower condenser 2 comprises a gas phase outlet arranged at the top and a liquid phase outlet arranged at the bottom, and the liquid phase outlet is connected to the liquid phase inlet at the upper part of the absorption tower 5 through a pipeline; the gas phase outlet at the top of the stripping tower condenser 2 is connected to the gas phase inlet at the lower part of the absorption tower 5 through a pipeline in sequence through a vacuum buffer tank 3 and a vacuum pump 4, the liquid phase outlet of the stripping tower condenser 2 is higher than the liquid phase inlet at the top of the absorption tower 5, the tower kettle of the absorption tower 5 is connected to an absorption tower circulating pump 7, the outlet of the absorption tower circulating pump 7 is connected to an absorption tower cooler 8, one outlet of the absorption tower cooler 8 is divided into two streams, one stream is connected to the absorption tower 5, and the other stream is connected to the out-of-bounds area, the tower kettle of the stripping tower 1 is connected to a recycled water pump 9, and a tail gas fan 6 is arranged at the top of the absorption tower 5. The stripping tower condenser 2 is directly connected to the stripping tower 1 through an equipment flange. The dilute ammonia water feed port of the stripping tower 1 is located in the middle of the tower, and the heat source feed port is connected to the tower kettle. The dilute ammonia water feed port is located above the distillation section, and the distillation section is located below the feed port. The packing type of the stripping tower 1 is a random packing or a structured packing. The packing height of the distillation section is 0.3 to 1.5 m, the packing height of the stripping section is 4 to 10 m, the skirt height is 5 to 8 m, and the height of the entire tower is 17 to 25 m. According to the concentration of the feed dilute ammonia water, the ratio of the stripping section to the distillation section tower diameter of the stripping tower 1 is between 3.0 and 0.9.

[0029] A liquid collecting weir is provided at the bottom of the lower part of the stripping tower condenser 2. The liquid phase outlet of the stripping tower condenser 2 is arranged on the side of the liquid collecting weir. The height of the liquid phase outlet is lower than the weir height of the liquid collecting weir. A part of the condensate condensed by the stripping tower condenser 2 is discharged from the liquid phase discharge port to the absorption tower 5, and the other part overflows from the top of the collecting weir and flows back into the stripping tower 1.

[0030] The absorption tower 5 is a packed tower, and its packing type is random packing or structured packing, the packing height is 1 to 4 meters, the whole tower height is 5 to 9 meters, and the height difference between the liquid phase outlet of the stripping tower condenser 2 and the liquid phase inlet of the absorption tower 5 is 8 to 20 meters. The liquid phase condensed by the stripping tower condenser 2 can enter the liquid phase inlet at the top of the stripping tower 1 through the gravity flow.

[0031] The temperature of the dilute ammonia water to be treated sent from the upstream device instead of circulating water in the cold side of the absorber cooler 8 is less than or equal to 32°C, and the dilute ammonia water after heat exchange still enters the middle part of the stripping tower 1.

[0032] The utility model provides a method for concentrating dilute ammonia water, comprising the following steps:

[0033] 1) The dilute ammonia water as a raw material from the upstream is sent to the middle part of the stripping tower 1, and the saturated low-pressure steam and hot water are directly added to the tower kettle as a heat source. After stripping, the qualified recycled water is discharged from the tower kettle through the recycled water pump 9; the concentration of the raw material dilute ammonia water is greater than or equal to 1500ppmwt, the concentration of the qualified recycled water after stripping is between 30 and 600pmmwt, the pressure of the saturated low-pressure steam as a heat source is greater than 0.1MPaG, the temperature of the hot water as a heat source is greater than 130°C, the saturated low-pressure steam and hot water as heat sources are used separately or mixed, and the stripping tower 1 is a packed tower operated in vacuum, and the operating pressure is 30 to 60kPaA.

[0034] 2) The non-condensable steam from the top of the stripping tower 1 after condensation through the stripping tower condenser 2 is high-concentration ammonia gas, and the non-condensable gas is sent to the bottom of the absorption tower 5 through the gas phase outlet through the interconnected vacuum buffer tank 3 and vacuum pump 4 for absorption; the reflux ratio of the stripping tower 1 is 0.3-3.0, and the concentration of the non-condensable high-concentration ammonia gas after condensation through the stripping tower condenser 2 is 40-90%, which is higher than the concentration of the concentrated ammonia solution product. By adjusting the reflux ratio of the stripping tower 1, the ratio of the sum of the ammonia content in the non-condensable steam gas phase discharge and the condensate liquid phase discharge at the top of the stripping tower condenser 2 to the sum of the total mass of the gas and liquid phase discharges is controlled to be greater than or equal to 20%wt, and fresh water can be added in the downstream absorption tower 5 for absorbing ammonia gas, and only the liquid phase discharge of the stripping tower 1 is used to absorb the gas phase discharge of the stripping tower 1 to obtain a concentrated ammonia solution product with a concentration greater than or equal to 20%wt. The reflux ratio of the stripping tower is adjusted to control the ratio of the sum of the ammonia content in the non-condensable vapor phase discharge and the condensate liquid phase discharge from the top of the stripping tower to the sum of the total mass to be greater than or equal to 20%wt. In the downstream absorption tower, no fresh water is required to be added to absorb the ammonia gas, and only the liquid phase discharge from the stripping tower is used to absorb the gas phase discharge from the stripping tower to produce a finished ammonia solution with a concentration greater than or equal to 20%wt.

[0035] 3) The condensate of the stripping tower condenser 2 is dilute ammonia water, which is collected at the liquid collection weir. By utilizing the potential difference between the stripping tower 1 and the absorption tower 5, the condensate flows into the upper part of the absorption tower 5 through the gas phase outlet by gravity flow as an absorbent; the condensate is ammonia water, and its concentration is 6-15%, which is lower than the concentration of the concentrated ammonia product. The operating pressure is normal pressure, the operating temperature is 38-45°C, and the operating pressure difference between the stripping tower 1 and the absorption tower 5 is 40-70kPa. The height difference between the stripping tower 1 and the absorption tower 5 is sufficient to overcome the pressure difference between the two towers, so that the condensate of the stripping tower 1 can flow into the top of the absorption tower 5 as an absorption liquid by gravity alone, reducing the use of pumps.

[0036] 4) After the bottom liquid is cooled by the absorber cooler 8, part of it is refluxed to the top of the absorber 5, and part of it is discharged as a concentrated ammonia finished product; the concentrated ammonia finished product discharged from the bottom of the absorber 5 has a concentration greater than or equal to 20%wt, and the recovery rate of ammonia in the finished concentrated ammonia is greater than or equal to 84%, and the remaining ammonia is free in the water discharged from the bottom of the stripping tower 1 and the tail gas discharged from the absorber 5; the bottom of the absorber 5 is cooled by the absorber cooler 8 and is divided into two streams, one of which is connected to the reflux port at the top of the absorber 5, and the other is sent out of the boundary area as a concentrated ammonia finished product, and the mass ratio of the reflux stream to the concentrated ammonia finished product discharge stream ranges from 0.5 to 2.5.

[0037] 5) A tail gas fan 6 is arranged on the top of the absorption tower 5 to prevent the pressure drop generated by the absorption tower 5 from causing back pressure at the outlet of the vacuum pump 4 to affect its normal operation. The outlet of the tail gas fan 6 is connected to the ammonia tail gas absorption system.

[0038] like Figure 1 As shown, a method for concentrating dilute ammonia water is provided in the utility model.

[0039] Technical Keywords

[0040] The technical keywords of this embodiment are: vacuum stripping, direct-connected stripping tower condenser 2, absorption liquid gravity flow, short process flow, small footprint, and simple equipment.

[0041] Device scale

[0042] The design capacity of this embodiment is to process 45 tons of ammonia-containing condensed water per hour and produce 516 kg of 22.4% ammonia water per hour.

[0043] Raw materials and product specifications

[0044] The raw material of this embodiment is water containing 3000 ppmwt of ammonia, and the product is 22.4%wt of ammonia water.

[0045] Brief description of process

[0046] Ammonia-containing condensed water from the upstream is sent to the middle of the stripping tower 1. The operating pressure of the stripping tower 1 is -0.06MPaG, and low-pressure steam and hot water are directly added to the bottom of the tower as a heat source. In the retention section, the ammonia content in the water is reduced to below 500ppmwt, and is sent out of the boundary area from the bottom of the tower through the recycling water pump 9. A direct-connected condenser is used at the top of the stripping tower 1, and the non-condensable gas extracted from the top of the tower is sent to the bottom of the absorption tower 5 through the vacuum pump 4. The condensate of the stripping tower condenser 2 is about 12%wt of dilute ammonia water. By utilizing the potential difference between the stripping tower 1 and the absorption tower 5, it can flow into the top of the absorption tower 5 as an absorbent by gravity. Since the process of ammonia dissolving in water is an exothermic process, an absorption liquid tower cooler is set at the bottom of the absorption tower 5 to remove the heat of dissolution. In order to make the ammonia concentration in the bottom of the absorption tower 5 meet the standard (>20%wt), the absorption liquid in the bottom of the tower is set to circulate back to the top of the tower. The tail gas blower 6 is arranged at the top of the absorption tower 5 to prevent the pressure drop caused by a series of equipment after the vacuum pump 4 from causing back pressure at the outlet of the vacuum pump 4 to affect its normal operation. The outlet of the tail gas blower 6 is sent to the ammonia tail gas absorption device outside the boundary area for treatment. In this embodiment, by controlling the reflux ratio of the stripping tower 1, the ratio of the sum of the ammonia content in the non-condensable vapor phase discharge and the condensate liquid phase discharge at the top of the stripping tower 1 to the sum of the total mass is greater than or equal to 20%wt, so that fresh water can be added to the top of the absorption tower 5 for absorbing ammonia.

[0047] Public works consumption

[0048] Power (water, electricity, steam, gas) consumption quota and consumption table

[0049]

[0050]

[0051] Note: The consumption quota of ammonia condensed water is calculated based on the treatment of one ton of ammonia condensed water, which is 45 tons per hour.

[0052] The consumption quota of ammonia water product is calculated based on the production of 22.4%wt ammonia water per ton, which means 0.516 tons are produced per hour.

[0053] Three Waste Discharge

[0054] 1) Exhaust gas

[0055] In this device, almost all ammonia gas is absorbed in the absorption tower 5 to form 22.4% ammonia water, and a small amount of ammonia overflows from the top of the absorption tower 5 and is sent to the ammonia tail gas absorption device for absorption. Therefore, in this embodiment, no exhaust gas is discharged.

[0056] 2) Wastewater

[0057] The free ammonia content of the ammonia-containing condensed water treated by the stripping tower 1 of the device can be reduced to below 500 ppmwt.

[0058] According to material balance, the ammonia gas discharged from absorption tower 5 is about 0.02kg / h. Assuming that the ammonia concentration in the tail gas water seal tank reaches 3%, it will be discharged and replaced with fresh water. This project will produce 5.3 tons of 3% dilute ammonia water per year (8,000 hours), which will be discharged to the sewage treatment plant.

[0059] Through energy-saving design ideas, by vacuum operating the stripping tower and setting a reasonable stripping tower condensation temperature, only 50kg of steam and 100kg of hot water (both refer to the unit consumption for treating each ton of ammonia-containing condensed water) are used to achieve an ammonia recovery rate of more than 85%, ensuring that the ammonia content at the bottom of the tower is less than 500ppmwt.

[0060] Equipment investment estimate and operating cost estimate

[0061] Equipment Investment Estimation Table

[0062]

[0063]

[0064] Operating cost estimate table

[0065]

[0066] Note: The consumption quota is calculated based on the production of 22.4%wt ammonia water per ton, which is 0.516 tons per hour.

[0067] 1) No new substances are added during the treatment of ammonia condensate, and the goal is achieved purely by distillation and absorption processes;

[0068] 2) 140°C hot water is used as one of the heat sources in this embodiment;

[0069] 3) The concentration of the recovered ammonia water is 22.4%wt, and the tail gas discharged after absorption by the tail gas absorption device (the tail gas absorption device is not included in this embodiment) does not contain ammonia, which fully meets the emission index requirements for ammonia in GB 14554-1993 "Odor Pollution Emission Standard";

[0070] 4) The ammonia concentration in the recycled water after gas stripping is less than 500 ppmwt;

[0071] 5) To treat 1 ton of water, 50 kg of steam is consumed, 0.31 kWh of electricity is used, and the operating cost is estimated to be 830.9 yuan per ton of ammonia water, which is the same as the price of ammonia water;

[0072] 6) The equipment investment for this embodiment is about 600,000 yuan, and the fixed asset investment for the entire project is expected to be no more than 1 million yuan;

[0073] 7) This embodiment is designed for continuous production. As long as the raw water flow is stable, combined with a simple automatic control embodiment, the device can achieve automatic operation. No human supervision is required during operation, only regular inspections are required.

[0074] Those skilled in the art can understand that the above are only preferred examples of the utility model and are not intended to limit the utility model. Although the utility model is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A dilute ammonia water concentration device, characterized in that: The device comprises a stripping tower (1), a stripping tower condenser (2) located at the top of the stripping tower (1) and connected to the stripping tower (1), and an absorption tower (5) connected to the stripping tower condenser (2), wherein the stripping tower condenser (2) comprises a gas phase outlet arranged at the top and a liquid phase outlet arranged at the bottom, and the liquid phase outlet is connected to the liquid phase inlet at the top of the absorption tower (5) through a pipeline; the gas phase outlet at the top of the stripping tower condenser (2) passes through a vacuum buffer tank (3), a vacuum pump (4) and a liquid phase inlet at the bottom of the absorption tower (5) in sequence through a pipeline. The gas phase inlet is connected, the liquid phase outlet of the stripping tower condenser (2) is higher than the liquid phase inlet at the top of the absorption tower (5), the tower kettle of the absorption tower (5) is connected to the absorption tower circulation pump (7), the outlet of the absorption tower circulation pump (7) is connected to the absorption tower cooler (8), one outlet of the absorption tower cooler (8) is divided into two streams, one stream is connected to the absorption tower (5), and the other stream is sent out of the boundary area as a concentrated ammonia product, the tower kettle of the stripping tower (1) is connected to a recycling water pump (9), and the tower top of the absorption tower (5) is provided with an exhaust fan (6).

2. The dilute ammonia water concentration device according to claim 1, characterized in that: The stripping tower condenser (2) is directly connected to the stripping tower (1) through an equipment flange. The dilute ammonia water feed port of the stripping tower (1) is located in the middle of the tower, and the heat source feed port is connected to the tower kettle. The dilute ammonia water feed port is located above the dilute ammonia water feed port, and the stripping section is located below the feed port. The packing type of the stripping tower (1) is a random packing or a structured packing. The packing height of the distillation section is 0.3 to 1.5 m, the packing height of the stripping section is 4 to 10 m, the skirt height is 5 to 8 m, the whole tower height is 17 to 25 m, and the ratio of the stripping section to the distillation section diameter of the stripping tower (1) is between 3.0 and 0.

9.

3. The dilute ammonia water concentration device according to claim 1 or 2, characterized in that: A liquid collecting weir is provided at the bottom of the lower part of the stripping tower condenser (2). The liquid phase outlet of the stripping tower condenser (2) is arranged on the side of the liquid collecting weir. The height of the liquid phase outlet is lower than the height of the liquid collecting weir. A part of the condensate condensed by the stripping tower condenser (2) is discharged from the liquid phase outlet to the absorption tower (5), and the other part overflows from the top of the collecting weir and flows back into the stripping tower (1).

4. The dilute ammonia water concentration device according to claim 3, characterized in that: The absorption tower (5) is a packed tower, and its packing type is random packing or structured packing. The packing height is 1 to 4 meters, and the height of the whole tower is 5 to 9 meters. The height difference between the liquid phase outlet of the stripping tower condenser (2) and the liquid phase inlet of the absorption tower (5) is 8 to 20 meters.

5. The dilute ammonia water concentration device according to claim 1, characterized in that: The cold side of the absorber cooler (8) uses the treated alternative dilute ammonia water sent from the upstream device instead of the circulating water. The temperature of the alternative dilute ammonia water is less than or equal to 32°C. After heat exchange, the dilute ammonia water still enters the middle part of the stripping tower.

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