Ammonia stripping column ammonia water vapor recovery device

Abstract

This application discloses an ammonia stripping tower ammonia-containing water vapor recovery device to solve the problems of high energy consumption, energy waste, and easy ammonia pollution in existing ammonia stripping tower ammonia-containing water vapor recovery methods. This application includes a pure water atomization device, a waste heat recovery unit, a primary cooler, a deep cooler, and a tail gas capture device. These components can be flexibly combined and configured according to the composition of the ammonia-containing vapor and the required concentration of ammonia water to be recovered. Under the premise of energy saving, environmental protection, stability, and a wide processing range, it achieves the recovery of high-purity, high-concentration ammonia water from ammonia stripping tower ammonia-containing water vapor. It can achieve energy saving, saving of circulating cooling water, compliance of ammonia tail gas, recovery of high-concentration ammonia water, and is applicable to the recovery and treatment of ammonia-containing vapor from ammonia stripping towers with various gas phase compositions. The entire system has great operational flexibility and extremely high stability. By configuring the waste heat recovery unit and the pure water atomization device, significant energy consumption and circulating cooling water consumption are saved during the operation of the ammonia stripping tower, avoiding energy waste.

Description

Technical Field

[0001] This application relates to the field of ammonia-containing wastewater technology, specifically to an ammonia stripping tower ammonia-containing water steam recovery device. Background Technology

[0002] Ammonia nitrogen wastewater has a wide range of sources, with large quantities generated from coal chemical, pharmaceutical, metallurgical, and landfill industries. This wastewater causes severe pollution and numerous environmental problems. A relatively economical ammonia removal technology for ammonia nitrogen wastewater is the stripping distillation method. The basic principle of stripping distillation is to directly or indirectly introduce high-temperature steam into the ammonia stripping tower. Ammonia nitrogen is recovered from the top of the tower as ammonia-containing water vapor, which mainly consists of ammonia gas, water vapor, and a small amount of non-condensable air.

[0003] Chinese patent CN219009958U (A Distillation Ammonia Removal System) proposes a two-stage condensation method for recovering ammonia-containing water vapor from a stripping tower. It uses a condenser to directly condense the ammonia-containing vapor, and the non-condensable tail gas is sent to a waste gas treatment system. The specific steps of condensation-absorption involve the ammonia-containing vapor passing through a two-stage condenser and an ammonia tail gas treatment device. This patent includes a top reflux tank and an ammonia water storage tank. The main disadvantages are: 1. The heat load released from the condensation of ammonia-containing vapor and the dissolution of ammonia is too high to be economically efficient when using chilled water for cooling. When using circulating cooling water, it is greatly affected by the local wet-bulb temperature. In southern regions with higher wet-bulb temperatures, this can easily lead to low ammonia absorption efficiency and secondary pollution; 2. The heat of the ammonia-containing water vapor is carried away by the circulating water, resulting in a significant waste of energy; 3. It is not suitable for treating high-concentration ammonia.

[0004] The ammonia recovery method proposed in Chinese patent CN104926009A (An Ammonia Nitrogen Wastewater Treatment System) involves condensation followed by absorption. First, a condenser directly cools the ammonia-containing vapor, then an absorption tower with an external cooler absorbs the ammonia, producing finished ammonia water from the absorption tower. Its main disadvantages are: 1. The absorption tower produces high-concentration ammonia water, resulting in high ammonia partial pressure and potential ammonia pollution; 2. The heat from the ammonia-containing vapor is carried away by circulating water, wasting a large amount of energy; 3. It is not suitable for treating high-concentration ammonia.

[0005] Both of the above-mentioned methods for recovering ammonia-containing steam in ammonia stripping towers have disadvantages such as high energy consumption, energy waste, easy generation of ammonia pollution, low operational flexibility, and inability to handle high-concentration ammonia. Summary of the Invention

[0006] Therefore, this application provides an ammonia stripping tower ammonia-containing water vapor recovery device to solve the problems of high energy consumption, energy waste and easy generation of ammonia pollution in existing ammonia stripping tower ammonia-containing water vapor recovery.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] An ammonia stripping tower ammonia-containing water vapor recovery device includes:

[0009] Ammonia vapor pipeline, its first end is connected to ammonia water vapor;

[0010] A waste heat recovery unit is provided with a waste heat recovery medium for recovering the heat of the ammonia vapor.

[0011] The primary cooler is connected to the waste heat recovery unit via a first pipe and to the deep cooler via a second pipe;

[0012] A pure water atomizing device, with one end connected to pure water and the other end connected to the first pipeline, is used to spray ammonia-containing vapor in the ammonia vapor pipeline and form an ammonia gas-liquid mixture.

[0013] The exhaust gas trap is connected to the deep cooler via a third pipe and is used to absorb non-condensable gases within the deep cooler.

[0014] Optionally, the waste heat recovery unit is a shell-and-tube heat exchanger or a plate heat exchanger.

[0015] Optionally, the waste heat recovery medium is the effluent from the ammonia stripping tower or saturated pure water.

[0016] Optionally, the pure water atomizing device includes a filtration module, a pressurization module, and an atomizing nozzle, wherein the atomizing nozzle is disposed inside the first pipe; the filtration module and the pressurization module are disposed outside the first pipe and located between the atomizing nozzle and the pure water, and the filtration module is used to filter the pure water.

[0017] Optionally, the booster module is a water pump; the filter module is a filter.

[0018] Optionally, the primary cooler is a shell-and-tube condenser or a shell-and-tube condenser with a liquid storage space, and its cooling medium is cooling water.

[0019] Optionally, the deep cooler is a shell-and-tube heat exchanger with a liquid storage space, and its cooling medium is cooling water or chilled water.

[0020] Optionally, the exhaust gas trap is a packed tower or a plate tower;

[0021] The exhaust gas capture device is divided into an upper tower and a lower tower. The diameter of the upper tower is smaller than that of the lower tower. The upper tower uses fresh pure water as the absorption medium, while the lower tower uses the upper pure water and the cooled bottom liquid as the absorption medium.

[0022] Optionally, the ratio of the diameter of the upper tower section to the diameter of the lower tower section is 1:1.1 to 1:2.

[0023] Optionally, the exhaust gas capture device is externally equipped with a spray pump and a cooling heat exchanger. The spray pump and the cooling heat exchanger are respectively connected to the upper and lower parts of the lower section tower, and the spray pump, the cooling heat exchanger and the lower section tower are connected by corresponding pipes to form a spray circulation, and a cold insulation layer is provided outside the corresponding pipes.

[0024] A fourth pipe is also connected to the pipe between the spray pump and the cooling heat exchanger, and the other end of the fourth pipe is connected to the pure water atomizing device.

[0025] Compared with the prior art, this application has at least the following beneficial effects:

[0026] 1. Based on further analysis and research of existing technical problems, this application recognizes that existing ammonia stripping tower ammonia-containing water vapor recovery methods suffer from high energy consumption, energy waste, and easy ammonia pollution. Therefore, it provides an ammonia stripping tower ammonia-containing water vapor recovery device, including a pure water atomizer, waste heat recovery unit, primary cooler, deep cooler, and tail gas capture unit. This device can be flexibly combined and configured according to the composition of the ammonia-containing steam and the required concentration of ammonia water to be recovered. Under the premise of energy saving, environmental protection, stability, and a wide processing range, it achieves the recovery of high-purity, high-concentration ammonia water from ammonia stripping tower ammonia-containing water vapor. It can achieve energy saving, saving of circulating cooling water, compliance of ammonia tail gas standards, recovery of high-concentration ammonia water, and is applicable to various applications. The ammonia stripping tower, composed of gaseous components, recovers and processes ammonia vapor. By configuring a waste heat recovery unit and a pure water atomization device, significant energy consumption and circulating cooling water consumption are saved during the operation of the ammonia stripping tower. Specifically, the pure water atomization device is suitable for situations with high ammonia concentrations (>20%). By introducing additional pure water to absorb ammonia, it reduces the ammonia concentration in the primary cooler and deep cooler, thereby reducing the partial pressure of ammonia in the gas phase. This also reduces ammonia escape during the discharge of non-condensable gases and alleviates the processing load on the tail gas capture device. The waste heat recovery unit is suitable for situations with high waste heat in the ammonia vapor. It can recover most of the heat from the ammonia vapor and then effectively utilize it, avoiding energy waste.

[0027] 2. This application has strong adaptability to fluctuations in the composition of ammonia vapor and the concentration of recovered ammonia water, and the entire system has great operational flexibility and extremely high stability.

[0028] 3. This application takes into account the new standards for exhaust gas absorption, strictly controls the leakage of ammonia in non-condensable gas, absorbs ammonia in non-condensable gas through circulating spraying, and installs a cold insulation layer outside the connecting pipe of the exhaust gas capture device to ensure that the operating temperature is <20℃ and the ammonia leakage is less than 0.6kg / h. Attached Figure Description

[0029] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0030] Figure 1 This is a schematic diagram of the structure of an ammonia stripping tower ammonia-containing water vapor recovery device provided in one embodiment of this application;

[0031] Figure 2 for Figure 1 A schematic diagram of the structure of the pure water atomization equipment.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Waste heat recovery unit; 2. Pure water atomization equipment; 201. Filter module; 202. Pressurization module; 203. Atomizing nozzle; 3. Primary cooler; 4. Deep cooler; 401. Ammonia water outlet; 402. Non-condensable gas outlet; 5. Tail gas capture device; 6. Spray pump; 7. Cooling heat exchanger; 8. Ammonia vapor pipeline; 9. First pipeline; 10. Second pipeline; 11. Third pipeline; 12. Fourth pipeline. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] In the description of this application: unless otherwise stated, "a plurality of" means two or more. The terms "first," "second," "third," etc., in this application are intended to distinguish the objects referred to and do not have any special meaning in terms of technical connotation (e.g., they should not be construed as an emphasis on importance or order). Expressions such as "comprising," "including," and "having" also mean "not limited to" (certain units, components, materials, steps, etc.).

[0036] The terms used in this application, such as "upper," "lower," "left," "right," and "middle," are generally used to indicate the general relative positional relationship for the purpose of intuitive understanding by referring to the accompanying drawings, and are not absolute limitations on the positional relationship in the actual product.

[0037] Example

[0038] An ammonia stripping tower ammonia-containing water vapor recovery device, such as Figure 1 , Figure 2 As shown, it includes: a pure water atomizing device 2, a waste heat recovery unit 1, a primary cooler 3, a deep cooler 4, a tail gas capture unit 5, and an ammonia vapor pipeline 8.

[0039] The first end of the ammonia vapor pipeline 8 is connected to ammonia water vapor (a mixture of ammonia, water vapor and air), and the last end is connected to the waste heat recovery unit 1; the total pressure of the ammonia water vapor in the ammonia stripping tower is 50-200 kPa (absolute pressure), the mole fraction of ammonia is 0-1, the mole fraction of water vapor is 0-0.99, and the mole fraction of air is 0-0.5.

[0040] The waste heat recovery unit 1 is equipped with a waste heat recovery medium, which recovers the heat of the ammonia vapor entering it.

[0041] The primary cooler 3 is connected to the waste heat recovery unit 1 through the first pipe 9, and is also connected to the deep cooler 4 through the second pipe 10;

[0042] One end of the pure water atomizing device 2 is connected to pure water, and the other end is connected to the first pipe 9. It is used to spray ammonia-containing vapor in the ammonia vapor pipe 8 and form an ammonia gas-liquid mixture.

[0043] The exhaust gas trap 5 is connected to the deep cooler 4 through the third pipe 11 and is used to absorb the non-condensable gas in the deep cooler 4. After the non-condensable gas is absorbed by the exhaust gas trap 5, it meets the standard and is then discharged.

[0044] In this embodiment, the waste heat recovery unit 1 includes a first inlet, a first outlet, a second inlet, and a second outlet. The first inlet is connected to the end of the ammonia-containing vapor pipeline 8, the second inlet is the waste heat recovery medium inlet, and the second outlet is the waste heat recovery medium outlet.

[0045] The primary cooler 3 includes a third inlet, a third outlet, a fourth inlet, and a fourth outlet. The third inlet is connected to the first outlet through the first pipe 9. The fourth inlet is a cooling water inlet, and the fourth outlet is a cooling water outlet.

[0046] The deep cooler 4 includes a fifth inlet, a fifth outlet, a sixth inlet, a sixth outlet and a non-condensable gas outlet 402. The fifth inlet is connected to the third outlet through the second pipe 10. The fifth outlet serves as an ammonia water outlet 401. The sixth inlet is a chilled water or cooling water inlet and the sixth outlet is a chilled water or cooling water outlet.

[0047] The exhaust gas capture device 5 includes a seventh inlet, an eighth inlet, a ninth inlet, and a seventh outlet. The seventh inlet is connected to the non-condensable gas outlet 402 through the aforementioned third pipe 11. The eighth inlet is connected to pure water. The ninth inlet is connected to the cooling heat exchanger 7 through a corresponding pipe. The seventh outlet is connected to the spray pump 6 through a corresponding pipe.

[0048] Preferably, the waste heat recovery unit 1 is a shell-and-tube heat exchanger or a plate heat exchanger.

[0049] More preferably, the waste heat recovery medium is the effluent from the ammonia stripping tower or saturated pure water.

[0050] The waste heat recovery medium recovers most of the heat from the ammonia-containing steam by exchanging heat with the ammonia stripping tower. The waste heat recovery medium can be the effluent from the ammonia stripping tower, saturated pure water, etc. The waste heat recovered by the waste heat recovery medium flows out of the system as secondary steam through a flash evaporator. Its quality can be improved by a compression or absorption heat pump for use in this system or other systems. The waste heat recovery rate is 40%-90% (relative to the ammonia-containing steam).

[0051] Preferably, the pure water atomizing device 2 includes a filtration module 201, a pressurizing module 202, and an atomizing nozzle 203. The atomizing nozzle 203 is disposed inside the first pipe 9. The filtration module 201 and the pressurizing module 202 are disposed outside the first pipe 9 and located between the atomizing nozzle 203 and the pure water. The filtration module 201 is used to filter the pure water.

[0052] The order in which the booster module 202 and the filter module 201 are arranged is as follows: One arrangement is to place the filter module 201 between the booster module 202 and the atomizing nozzle 203, such as... Figure 1 , Figure 2 As shown;

[0053] Another method involves placing a booster module 202 between the filter module 201 and the atomizing nozzle 203. The booster module 202 delivers filtered pure water to the atomizing nozzle 203, where it is compressed to form atomized particles. After passing through the filter module 201, the pure water enters the booster module 202, where it is compressed by the nozzle to form atomized particles, which are then sprayed onto the ammonia vapor.

[0054] More preferably, the booster module is a booster, such as a water pump; and the filter module is a filter.

[0055] The pure water entering the filter module 201 can be introduced from the boundary area or absorbed by the exhaust gas capture device 5. The main purpose of the pure water atomization device 2 is to reduce the partial pressure of the terminal condensed ammonia gas and reduce the ammonia emissions in the exhaust gas under the condition of high concentration of ammonia vapor. At the same time, the higher ammonia concentration helps to save the heat load of the stripping deammoniation tower, reduce the steam consumption of the stripping tower, and realize energy saving of the deammoniation stripping tower.

[0056] Preferably, the primary cooler 3 is a shell-and-tube condenser or a shell-and-tube condenser with a liquid storage space, and uses ordinary circulating cooling water as the cooling medium; the primary cooler 3 is connected to the waste heat recovery unit 1 through the first pipe 9 mentioned above, and the ammonia vapor and ammonia water in the waste heat recovery unit 1 enter the primary cooler 3.

[0057] More preferably, the deep cooler 4 is a shell-and-tube heat exchanger with a liquid storage space, using ordinary circulating cooling water or chilled water (-20℃–20℃) as the cooling medium; the deep cooler 4 is connected to the primary cooler 3 through the aforementioned second pipe 10, and the deep cooler 4 is usually arranged below the primary cooler 3. When the wet-bulb temperature is less than 20℃, the deep cooler 4 uses ordinary circulating cooling water as the cooling medium, and when the wet-bulb temperature is greater than 20℃, the deep cooler 4 uses chilled water as the cooling medium.

[0058] Preferably, the exhaust gas trap 5 is a packed tower or a plate tower; the exhaust gas trap 5 is divided into an upper tower and a lower tower, and the diameter of the upper tower is smaller than that of the lower tower.

[0059] More preferably, the ratio of the diameter of the upper tower section to the diameter of the lower tower section is 1:1.1-1:2; more preferably, it is 1:1.4.

[0060] More preferably, the exhaust gas capture device 5 uses a circulating spray method to absorb ammonia in the non-condensable gas. Specifically, the exhaust gas capture device 5 is equipped with a spray pump 6 and a cooling heat exchanger 7 on its exterior. The spray pump 6 and the cooling heat exchanger 7 are respectively connected to the upper and lower parts of the lower section tower. The spray pump 6, the cooling heat exchanger 7, and the lower section tower are connected by corresponding pipes to form a spray circulation, and a cold insulation layer is installed outside the corresponding pipes.

[0061] A fourth pipe 12 is also connected to the pipe between the spray pump 6 and the cooling heat exchanger 7. The other end of the fourth pipe 12 is connected to the pure water atomizing device 2.

[0062] The upper section of the tower uses fresh pure water as the absorption medium, while the lower section uses the upper section pure water and the cooled bottom liquid as the absorption medium. When the wet-bulb temperature of the external cooling heat exchanger 7 is less than 15°C, the deep cooler 4 uses ordinary circulating cooling water as the cooling medium. When the wet-bulb temperature is greater than 15°C, the deep cooler 4 uses chilled water as the cooling medium. The pipes connected to the exhaust gas trap 5 are equipped with a cold insulation layer to ensure that the operating temperature is <20°C and the ammonia leakage is less than 0.6 kg / h.

[0063] This ammonia stripping tower ammonia-containing steam recovery unit can be flexibly configured according to the composition of the ammonia-containing steam and the required concentration of recovered ammonia water; including but not limited to the following combinations:

[0064] The first combination is a combination of waste heat recovery unit 1, pure water atomization equipment 2, primary cooler 3, deep cooler 4, and exhaust gas capture unit 5; this combination is suitable for recovering waste heat with ≥30% heat, ammonia mass concentration >25%, and recovering ammonia water with >18% heat.

[0065] The second combination consists of a waste heat recovery unit 1, a pure water atomization device 2, a primary cooler 3, and a tail gas capture device 5. This combination is suitable for recovering waste heat with a heat content of ≥30% and ammonia concentration >25%, and recovering ammonia water with a heat content of ≤18%.

[0066] The third combination: a combination of pure water atomizer 2, primary cooler 3, and exhaust gas capture device 5; this combination is suitable for water with no waste heat recovery, ammonia mass concentration >25%, and ammonia recovery ≤18%;

[0067] The fourth combination is a combination of waste heat recovery unit 1, primary cooler 3, deep cooler 4, and exhaust gas capture unit 5. This combination is suitable for recovering waste heat with a heat content of ≥30% and ammonia concentration of ≤25%, and for recovering ammonia water with a heat content of >18%.

[0068] The fifth combination is a combined equipment consisting of a waste heat recovery unit 1, a primary cooler 3, and a tail gas capture unit 5. This combined equipment is suitable for recovering waste heat with a heat content of ≥30%, ammonia mass concentration ≤25%, and ammonia water with a heat content of ≤18%.

[0069] The sixth combination is a combination of primary cooler 3, deep cooler 4, and exhaust gas capture device 5. This combination is suitable for applications where waste heat is not recovered, ammonia concentration is ≤25%, and ammonia water with a concentration >18% is recovered.

[0070] The circulating cooling water is prepared by either an open or closed cooling tower, with an initial water temperature of 10℃–35℃ and a temperature difference of 5℃–20℃. The chilled water is prepared by a heat pump refrigeration unit, with an initial water temperature of -20℃–20℃ and a temperature difference of 3℃–20℃. High-purity, high-concentration ammonia water can be extracted from the deep cooler 4 in this device. The purity of the ammonia water meets the industrial ammonia water standard HG / T 5353-2018, with a mass concentration of 5%–50%.

[0071] Taking the first combination as an example, the process flow of this ammonia stripping tower ammonia steam recovery device is as follows: After being collected by ammonia steam pipeline 8, the ammonia steam first enters the waste heat recovery unit 1. The waste heat recovery unit 1 recovers the heat of the ammonia steam through the waste heat recovery medium. The heat recovered by the waste heat recovery medium can be output and reused in the stripping ammonia removal tower or other hot spots in the plant area. The ammonia steam enters the primary cooler 3 after being cooled. At the same time, pure water atomization equipment 2 passes through the first pipeline 9 between the waste heat recovery unit 1 and the primary cooler 3. Pure water is sprayed to form an ammonia gas-liquid mixture, which then enters the primary cooler 3. After being cooled by the primary cooler 3, it enters the deep cooler 4. After being cooled by the deep cooler 4, ammonia water is extracted. Non-condensable gas and a small amount of ammonia gas enter the tail gas capture device 5. The tail gas capture device 5 absorbs the ammonia gas through a circulating spray, and the non-condensable gas that meets the standards is finally discharged. At the same time, the absorbed liquid of the tail gas capture device 5 can be transported to the pure water atomization device 2 through the fourth pipeline 12 to spray the ammonia water vapor in the first pipeline 9.

[0072] Application example:

[0073] Example 1

[0074] The ammonia-containing steam from the ammonia stripping tower has a total mass flow rate of 10.1 t / h (ammonia gas mass flow rate 1.5 t / h, steam mass flow rate 8.5 t / h, air mass flow rate 0.1 t / h). It enters waste heat recovery unit 1 to recover heat, using 82°C saturated water as the waste heat recovery medium. The heat recovered by the waste heat recovery medium is output to the system as 82°C secondary steam. After compression by a two-stage centrifugal compressor, it yields 118°C steam, which can be reused in the stripping ammonia removal tower or other hot spots in the plant. The ammonia-containing steam is 10.1 t / h. After being cooled to 87℃, the ammonia gas flows into the primary cooler 3. 5t / h of pure water is sprayed through a pure water atomization energy-saving device on the pipeline between the waste heat recovery unit 1 and the primary cooler 3. The cooling outlet temperature of the primary cooler 3 is 50℃. Further, 15.1t / h of the ammonia gas-liquid mixture enters the deep cooler 4 to be cooled to 30℃, and the ammonia water is collected as the product. Non-condensable gas and a small amount of ammonia gas enter the tail gas trap 5. The tail gas trap 5 operates at 19℃, the pure water temperature is 15℃, the pure water inflow rate is 0.2t / h, and the tail gas ammonia leakage rate is 0.13kg / h.

[0075] Example 2

[0076] The ammonia-containing steam from the ammonia stripping tower has a total mass flow rate of 10.05 t / h (ammonia mass flow rate 1.5 t / h, steam mass flow rate 8.5 t / h, and air mass flow rate 0.05 t / h). This 10.05 t / h of ammonia-containing steam enters the waste heat recovery unit 1 through pipelines to recover heat. Saturated water at 80°C is used as the waste heat recovery medium. The heat recovered by the medium is output to the system as 80°C secondary steam. After compression by a twin-screw steam compressor, it yields 115°C steam. It can be reused in the stripping ammonia removal tower or other hot spots in the plant area; 10.05 t / h of ammonia gas-liquid mixture is cooled to 85°C and then enters the primary cooler 3. The outlet temperature of the primary cooler 3 is 45°C. The further 10.05 t / h of ammonia gas-liquid mixture enters the deep cooler 4 and is cooled to 30°C. Ammonia water is collected as a product; non-condensable gas and a small amount of ammonia gas enter the tail gas capture device 5. The operating temperature of the tail gas capture device 5 is 19°C, the pure water temperature is 15°C, the pure water inflow rate is 0.1 t / h, and the tail gas ammonia leakage rate is 0.08 kg / h.

[0077] Example 3

[0078] The ammonia-containing steam from the ammonia stripping tower has a total mass flow rate of 10.07 t / h (ammonia gas mass flow rate 1.5 t / h, steam mass flow rate 8.5 t / h, air mass flow rate 0.07 t / h). This 10.07 t / h of ammonia-containing steam enters the waste heat recovery unit 1 through a pipeline to recover heat. A gas-liquid mixture of 100 t / h stripping tower bottom water (reduced pressure, 52 kPa) is used as the waste heat recovery medium. The heat recovered by the waste heat recovery medium is output as secondary steam at 78°C. The system, after being compressed by a single-screw steam compressor, produces 115°C steam, which can be reused in the stripping ammonia removal tower or other hot spots in the plant area; the ammonia gas-liquid mixture of 10.07 t / h is cooled to 83.5°C and then enters the primary cooler 3. The cooling outlet temperature of the primary cooler 3 is 30°C, and the ammonia water is collected as the product; the non-condensable gas and a small amount of ammonia gas enter the tail gas capture device 5. The tail gas capture device 5 operates at a temperature of 19°C, the pure water temperature is 15°C, the pure water inflow rate is 0.1 t / h, and the tail gas ammonia leakage rate is 0.1 kg / h.

[0079] Example 4

[0080] The ammonia-containing steam from the ammonia stripping tower has a total mass flow rate of 1.005 t / h (ammonia gas mass flow rate 0.3 t / h, steam mass flow rate 0.7 t / h, and air mass flow rate 0.005 t / h). The ammonia-containing steam enters waste heat recovery unit 1 through pipelines to recover heat. Saturated water at 75°C is used as the waste heat recovery medium. The heat recovered by the waste heat recovery medium is output to the system as 75°C secondary steam. After passing through a lithium bromide absorption heat pump, 110°C steam is obtained, which can be reused in the stripping and ammonia removal process. The tower or other hot spots in the plant area; 1 t / h of pure water is sprayed through a pure water atomization energy-saving device on the pipeline between the waste heat recovery unit 1 and the primary cooler 3; 2.005 t / h of ammonia gas-liquid mixture is cooled to 80°C and then enters the primary cooler 3. The cooling outlet temperature of the primary cooler 3 is 30°C, and ammonia water is extracted as a product; non-condensable gas and a small amount of ammonia gas enter the tail gas capture unit 5. The operating temperature of the tail gas capture unit 5 is 19°C, the pure water temperature is 15°C, the pure water inflow rate is 0.05 t / h, and the tail gas ammonia leakage rate is 0.05 kg / h.

[0081] In summary, this application has at least the following advantages:

[0082] 1. Includes pure water atomization equipment; 2. waste heat recovery unit; 3. primary cooler; 4. deep cooler; 5. exhaust gas capture unit. These components can be flexibly combined and configured according to the composition of ammonia-containing vapor and the required concentration of ammonia water to be recovered. Under the premise of energy saving, environmental protection, stability, and a wide processing range, it enables the recovery of high-purity, high-concentration ammonia water from ammonia-containing vapor in an ammonia stripping tower. It achieves energy savings, savings in circulating cooling water, compliance of ammonia exhaust gas, recovery of high-concentration ammonia water, and is suitable for the recovery and treatment of ammonia-containing vapor in ammonia stripping towers with various gas phase compositions.

[0083] 2. The configuration of waste heat recovery unit 1 and pure water atomization equipment 2 saves a significant amount of energy and circulating cooling water consumption during the operation of the ammonia stripping tower. Specifically, the pure water atomization equipment 2 is suitable for situations with high ammonia concentrations (>20%). By introducing additional pure water to absorb ammonia, it reduces the ammonia concentration in the primary cooler 3 and the deep cooler 4, thereby reducing the partial pressure of ammonia in the gas phase. This also reduces ammonia escape during the discharge of non-condensable gases and alleviates the processing load on the tail gas capture device 5. The waste heat recovery unit 1 is suitable for situations with high waste heat in the ammonia vapor. It can recover most of the heat from the ammonia vapor and then effectively utilize it, avoiding energy waste.

[0084] 3. In view of the new standards for exhaust gas absorption, strictly control the leakage of ammonia in non-condensable gases, with the leakage rate of ammonia less than 0.6 kg / h;

[0085] 4. It has strong adaptability to fluctuations in the composition of ammonia vapor and the concentration of recovered ammonia water, and the whole system has great operational flexibility and extremely high stability.

[0086] The technical features of the above embodiments can be combined in any way (as long as there is no contradiction in the combination of these technical features). For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; these embodiments not explicitly written should also be considered to be within the scope of this specification.

Claims

1. An ammonia stripping tower ammonia-containing steam recovery device, characterized in that, include: Ammonia vapor pipeline, its first end is connected to ammonia water vapor; A waste heat recovery unit is provided with a waste heat recovery medium for recovering the heat of the ammonia vapor. The primary cooler is connected to the waste heat recovery unit via a first pipe and to the deep cooler via a second pipe; A pure water atomizing device, with one end connected to pure water and the other end connected to the first pipeline, is used to spray ammonia-containing vapor in the ammonia vapor pipeline to form an ammonia gas-liquid mixture. The pure water atomizing device includes a filtration module, a pressurization module, and an atomizing nozzle. The atomizing nozzle is disposed inside the first pipeline. The filtration module and the pressurization module are disposed outside the first pipeline and located between the atomizing nozzle and the pure water. The filtration module is used to filter the pure water. The exhaust gas trap is connected to the deep cooler via a third pipe and is used to absorb non-condensable gases within the deep cooler. The exhaust gas trap is divided into an upper tower and a lower tower. A spray pump and a cooling heat exchanger are installed outside the exhaust gas trap. The spray pump and the cooling heat exchanger are connected to the upper and lower parts of the lower tower, respectively, and a spray circulation is formed between the spray pump, the cooling heat exchanger, and the lower tower through corresponding pipes. A cold insulation layer is installed outside the corresponding pipes. A fourth pipe is also connected to the pipe between the spray pump and the cooling heat exchanger, and the other end of the fourth pipe is connected to the pure water atomizing device.

2. The ammonia stripping tower ammonia-containing steam recovery device according to claim 1, characterized in that, The waste heat recovery unit is a shell-and-tube heat exchanger or a plate heat exchanger.

3. The ammonia stripping tower ammonia-containing steam recovery device according to claim 2, characterized in that, The waste heat recovery medium is the effluent from the ammonia stripping tower or saturated pure water.

4. The ammonia stripping tower ammonia-containing steam recovery device according to claim 1, characterized in that, The booster module is a water pump; the filter module is a filter.

5. The ammonia stripping tower ammonia-containing steam recovery device according to claim 1, characterized in that, The primary cooler is a shell-and-tube condenser or a shell-and-tube condenser with a liquid storage space, and its cooling medium is cooling water.

6. The ammonia stripping tower ammonia-containing steam recovery device according to claim 1 or 5, characterized in that, The deep cooler is a shell-and-tube heat exchanger with a liquid storage space, and its cooling medium is cooling water or chilled water.

7. The ammonia stripping tower ammonia-containing steam recovery device according to claim 1, characterized in that, The exhaust gas capture device is a packed tower or a plate tower; The diameter of the upper column is smaller than that of the lower column; the upper column uses fresh pure water as the absorption medium, and the lower column uses the upper column pure water and the cooled bottom liquid as the absorption medium.

8. The ammonia stripping tower ammonia-containing steam recovery device according to claim 7, characterized in that, The ratio of the diameter of the upper tower section to the diameter of the lower tower section is 1:1.1-1:2.

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