Deodorization system with ammonia recovery for a compost reactor

Abstract

This utility model discloses a deodorization system with ammonia recovery for a composting reactor, including a deodorization unit and an ammonia recovery unit. The air inlet of the deodorization unit is connected to the air outlet of the composting reactor, and the air outlet of the deodorization unit is connected to a chimney. The deodorization unit is used to treat the odorous gas generated by the composting reactor. The ammonia recovery unit is connected to the deodorization unit and is used to recover ammonia from the deodorized wastewater generated by the deodorization unit. The ammonia recovery unit includes a water collection tank, a preheater, a distillation column, a cooling device, and an ammonia tank. The water collection tank is used to collect the deodorized wastewater generated by the deodorization unit. The outlet of the water collection tank is connected to the first inlet of the preheater. The outlet of the preheater is connected to the middle inlet of the distillation column. The bottom outlet of the distillation column is connected to the second inlet of the preheater. The top outlet of the distillation column is connected to the inlet of the cooling device. This deodorization system has a good deodorization effect and can simultaneously realize ammonia recovery and wastewater purification.

Description

Technical Field

[0001] This utility model relates to the field of composting technology, and in particular to a deodorization system with ammonia recovery for a composting reactor. Background Technology

[0002] Vertical closed composting reactors have become the mainstream technology for treating livestock and poultry manure both domestically and internationally due to their advantages such as small footprint and high processing efficiency. Closed composting reactors are sealed tanks with high processing efficiency, but the odor they produce is characterized by high temperature, high humidity, and high concentration (ammonia accounts for 98.70% of the compost odor, with a concentration as high as 1713.92 mg / m³). 3 It has the characteristics of centralized emission.

[0003] Currently, odorous gases from closed composting reactors are typically treated using end-of-pipe deodorization equipment such as multi-stage spray towers and biological filters. While this ensures effective deodorization, it also generates large quantities of high-concentration deodorized wastewater. Ammonia is the main component of the odorous gases from composting reactors, resulting in wastewater characterized by low carbon (500 mg / L) and high ammonia nitrogen concentration (6000 mg / L). This severe imbalance in the carbon-to-nitrogen ratio necessitates the addition of sufficient carbon sources before biological denitrification processes (such as single-stage or two-stage A / O, SBR, short-cut nitrification-denitrification, and anaerobic ammonia oxidation) can be used, leading to high treatment costs per ton of wastewater (>20 RMB / ton). Furthermore, biological denitrification focuses on ammonia removal rather than recovery, resulting in a waste of ammonia nitrogen resources.

[0004] Numerous studies have shown that the most economical and feasible ammonia reduction or recovery technologies are permeable membrane stripping, aeration stripping, and thermal vacuum stripping, all of which are physical methods. Among these, steam stripping of ammonia has been widely used in recent years due to its advantages such as no secondary pollution, simple treatment process, and resource recovery of ammonia water. Distillation technology is a type of steam stripping of ammonia. Research reports indicate that, excluding depreciation costs, distillation technology can be used to strip ammonia from a daily production of 2400 m³ / h. 3 The treatment cost for recovering ammonia from high-ammonia nitrogen wastewater (8000 mg / L / day) is 21.3 yuan per ton of wastewater. The revenue from the recovered ammonia is 27.97 yuan per ton of wastewater, equivalent to 1 m³ of wastewater treated. 3High-ammonia nitrogen wastewater can generate a profit of 6.67 yuan, showing significant economic benefits and even offsetting some deodorization costs. However, directly using distillation equipment to recover ammonia from high-temperature fermentation odors often affects the normal exhaust of the composting reactor and may even affect the fermentation effect and processing capacity of the materials within the reactor. Therefore, without affecting the fermentation of materials in the composting reactor, this invention innovatively integrates distillation technology into the deodorization wastewater purification process for high-temperature, high-humidity, and high-ammonia odors generated during the treatment of livestock and poultry manure in a closed composting reactor. This constructs a closed-loop system of "ammonia recovery—wastewater treatment—resource recycling." The recovered high-concentration ammonia water generates revenue and can further reduce the deodorization costs of the composting reactor, achieving multiple benefits. Utility Model Content

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a deodorization system with ammonia recovery for composting reactors, which effectively solves the problems of difficult treatment and high treatment cost of deodorization wastewater generated at the end of composting reactors in the prior art.

[0006] According to one aspect of the present invention, a deodorization system with ammonia recovery for a composting reactor is provided, comprising:

[0007] The deodorization unit has an air inlet connected to the air outlet of the composting reactor and an air outlet connected to the chimney. The deodorization unit is used to treat the odor generated by the composting reactor.

[0008] An ammonia recovery unit is connected to a deodorization unit and is used to recover ammonia from the deodorization wastewater generated by the deodorization unit. The ammonia recovery unit includes a water collection tank, a preheater, a distillation column, a cooling device, and an ammonia tank. The water collection tank is used to collect the deodorization wastewater generated by the deodorization unit. The outlet of the water collection tank is connected to the first inlet of the preheater. The outlet of the preheater is connected to the middle inlet of the distillation column. The bottom outlet of the distillation column is connected to the second inlet of the preheater. The top outlet of the distillation column is connected to the inlet of the cooling device. The outlet of the cooling device is connected to the ammonia tank.

[0009] In this invention, the fermentation odor from the composting reactor is purified by the deodorization unit and then discharged from the chimney in compliance with standards. The deodorized wastewater generated by the deodorization unit enters the collection tank in the ammonia recovery unit. After being preheated by the preheater, the deodorized wastewater enters the middle of the distillation tower. The distillation tower distills the deodorized wastewater to efficiently distill out the ammonia. The ammonia is then condensed into high-concentration ammonia water by the cooling device and stored in the ammonia water tank.

[0010] In some embodiments, the cooling device includes a first-stage cooler, a reflux tank, and a second-stage cooler. The inlet of the first-stage cooler is connected to the top outlet of the distillation column, the first outlet of the first-stage cooler is connected to the top inlet of the reflux tank, the bottom outlet of the reflux tank is connected to the upper inlet of the distillation column, the second outlet of the first-stage cooler is connected to the inlet of the second-stage cooler, and the outlet of the second-stage cooler is connected to an ammonia tank. The high-ammonia gas distilled from the distillation column enters the first-stage cooler from the top outlet of the distillation column for condensation. The temperature of the ammonia vapor at the outlet of the first-stage cooler is adjusted by regulating the amount and temperature of the cooling water used, thus controlling the concentration of ammonia entering the reflux tank. The ammonia water cooled by the first stage in the reflux tank is sprayed from the bottom outlet of the reflux tank through nozzles powered by a reflux pump and re-enters the upper part of the distillation column for further distillation and concentration of ammonia. The ammonia gas that is not condensed in the first-stage cooler continues to enter the second-stage condenser, where it is condensed into qualified ammonia water, which is then stored in the ammonia tank.

[0011] In some embodiments, the ammonia recovery unit further includes a reboiler located adjacent to the distillation column. The reboiler provides a heat source to the distillation column from the bottom, maintaining the liquid inside at 100°C. The reboiler electrically heats the heat transfer oil within it, which is continuously circulated internally by a pump connected to the heat transfer oil on the outer surface of the bottom of the distillation column. This maintains a consistently high-temperature environment for ammonia distillation within the distillation column and ensures low ammonia levels in the purified water at the bottom. By installing a reboiler, a consistently high-temperature environment at the bottom of the distillation column can be maintained, ensuring that the deodorized wastewater and ammonia in the reflux tank are distilled off during the spraying process into the distillation column, achieving further concentration of ammonia and purification of the deodorized wastewater.

[0012] In some embodiments, the ammonia recovery unit further includes a purified water tank, the inlet of which is connected to the bottom outlet of the distillation column. The purified water from the bottom of the distillation column after ammonia stripping is periodically discharged into the purified water tank for storage.

[0013] In some embodiments, the deodorization unit includes a three-stage spray deodorization device, a heat exchange device, and a fan. The three-stage spray deodorization device includes a first-stage spray tower, a second-stage spray tower, and a third-stage spray tower connected sequentially by pipes. The heat exchange device is connected to the first-stage spray tower by a pipe. The air outlet at the top of the composting reactor is connected to the air inlet at the bottom of the first-stage spray tower by a pipe equipped with a fan. The air outlet at the top of the third-stage spray tower is connected to a chimney by a pipe. The three spray towers are connected in series. The fan is connected to the bottom of the first-stage spray tower by a pipe. The top of the first-stage spray tower is connected to the bottom of the second-stage spray tower by a pipe. The top of the second-stage spray tower is connected to the bottom of the third-stage spray tower by a pipe. The fan provides power to purify the odorous gas in the composting reactor by passing it sequentially through the three spray towers before it is discharged through the chimney in compliance with emission standards.

[0014] In some embodiments, the first-stage, second-stage, and third-stage spray towers are equipped with a spraying mechanism, a packing layer, and a bottom water tank, arranged sequentially from top to bottom. Water in the bottom water tank of the third-stage spray tower is sprayed out through the spraying mechanism, making full contact with the odorous gases in the packing layer of the spray tower through countercurrent flow, thus absorbing the odorous gases such as ammonia.

[0015] In some embodiments, the spraying mechanism includes a spray pipe and a nozzle, the nozzle being disposed on the spray pipe. The nozzle sprays water to facilitate a thorough gas-liquid exchange with the odor.

[0016] In some embodiments, the heat exchange device includes a plate heat exchanger and an air-cooled tower. The plate heat exchanger is equipped with a first hot water pipe, a second hot water pipe, a first cold water pipe, and a second cold water pipe. Hot water from the water tank at the bottom of the first-stage spray tower enters the first hot water pipe. The plate heat exchanger and the air-cooled tower are connected via the second hot water pipe. Cooling water from the air-cooled tower enters the second cold water pipe. The first cold water pipe is connected to the spray pipes of the first-stage spray tower. The heat exchange device is used to cool the liquid in the first-stage spray tower, which can improve the efficiency of odor absorption such as ammonia during the counter-current gas-liquid exchange between odorous gases and spray water in the packing layer of the first-stage spray tower.

[0017] In some embodiments, the bottom water tank of the first-stage spray tower is connected to a plate heat exchanger via a first hot water pipe. After exchanging heat with the plate heat exchanger, the first cold water pipe on the plate heat exchanger is connected to the spray pipe of the first-stage spray tower. The spray pipes of the second-stage and third-stage spray towers are respectively connected to the bottom water tanks of the second-stage and third-stage spray towers via pipes.

[0018] In some embodiments, the bottom water tanks of the first-stage, second-stage, and third-stage spray towers are connected to the inlet of a collection pool via pipelines, and the outlet of the purified water pool is connected to the bottom water tanks of the first-stage, second-stage, and third-stage spray towers via pipelines. When the spray water in the three spray towers reaches saturation from absorbing ammonia and other odors, it is replaced. This saturated, heated deodorized wastewater is pumped into the collection pool for storage, to be used for distillation to recover ammonia water, thus purifying the deodorized wastewater. The purified water in the purification pool is then partially reused in the spray towers to continue absorbing ammonia from the compost odors.

[0019] The beneficial effects of this utility model are as follows:

[0020] 1. This utility model provides a deodorization system with ammonia recovery for composting reactors. It recovers ammonia from the high-temperature, high-humidity odorous gases in a closed composting reactor, combining distillation technology with the purification of deodorized wastewater generated from odor treatment. This deodorization system addresses the pain point of ammonia emission reduction in the livestock and poultry farming industry. Without affecting the composting reactor's harmless treatment of livestock and poultry manure or its normal exhaust gas requirements, it achieves simultaneous and coordinated "solid waste treatment—odor control—resource recovery," breaking through the traditional industry approach of "biological denitrification + end-of-pipe treatment." From the low-carbon, high-ammonia deodorized wastewater derived from the odor treatment stage of the composting reactor, ammonia is simultaneously recovered (converted into ammonia water) and purified using distillation technology, avoiding the high cost of traditional biological denitrification processes. It constructs a complete resource recycling system of "harmless treatment of livestock and poultry manure → high-ammonia odor purification → ammonia recovery from deodorized wastewater → ammonia water value-added utilization," achieving "zero nitrogen emissions" and full nutrient recovery, completely eliminating secondary pollution.

[0021] 2. This utility model has broad applicability and can be extended to nitrogen-containing solid wastes treated by various closed composting reactors such as garbage, covering multiple fields such as livestock and poultry breeding and municipal solid waste, with broad market demand.

[0022] 3. This utility model has environmental benefits such as reducing ammonia emissions from livestock and poultry farming, reducing air pollution and greenhouse gas emissions, and helping to achieve the "dual carbon" goal; moreover, the recovered ammonia water products can be used as agricultural fertilizer or industrial raw materials, generating benefits to reduce deodorization costs, improve the profitability of composting projects, and form an economic closed loop.

[0023] 4. This utility model conforms to the national policy of "pollution reduction and carbon reduction, and resource recycling", therefore, the deodorization system has significant social, economic and environmental benefits. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of this utility model.

[0025] In the diagram: 1. Compost reactor; 2. Blower; 3. First-stage spray tower; 4. Second-stage spray tower; 5. Third-stage spray tower; 6. Chimney; 7. Spray pipe; 8. Nozzle; 9. Packing layer; 10. Bottom water tank; 11. Plate heat exchanger; 12. Air-cooled tower; 13. First hot water pipe; 14. Second hot water pipe; 15. First cold water pipe; 16. Second cold water pipe; 17. Water collection tank; 18. Preheater; 19. Distillation column; 20. Reboiler; 21. Purified water tank; 22. First-stage cooler; 23. Reflux tank; 24. Second-stage cooler; 25. Ammonia tank; 26. Circulating water pump; 27. Drain pump; 28. Inlet pump; 29. ​​Reclaimed water pump; 30. Reflux pump. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] The present invention and its embodiments are described below. This description is not restrictive, and the actual embodiments are not limited thereto. In short, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

[0028] Currently, common end-of-pipe deodorization equipment for odorous gases generated by closed composting reactors includes spray towers, filters, and trickling filters. However, both filters and spray towers use clean water or chemical agents to achieve rapid ammonia reduction and deodorization. While this ensures effective deodorization, it generates a large amount of deodorization wastewater. Given that ammonia is the main component of the odorous gases from composting reactors, the deodorization wastewater is characterized by low carbon and high ammonia nitrogen. This severe imbalance in the carbon-to-nitrogen ratio makes commonly used biological denitrification wastewater treatment processes extremely difficult, requiring the addition of sufficient carbon sources and adequate retention time, resulting in very high investment and operating costs for wastewater treatment facilities. Considering the high temperature and high ammonia nitrogen characteristics of this deodorization wastewater, distillation technology for ammonia recovery is particularly suitable.

[0029] To address the aforementioned shortcomings of existing technologies, this utility model provides a deodorization system with ammonia recovery for composting reactors, effectively solving the problems of high investment, difficult treatment of deodorized wastewater, and excessively high treatment costs associated with existing end-of-pipe deodorization methods for composting reactors.

[0030] refer to Figure 1This utility model provides a deodorization system with ammonia recovery for a composting reactor, including a deodorization unit and an ammonia recovery unit. The air inlet of the deodorization unit is connected to the air outlet of the composting reactor 1, and the air outlet of the deodorization unit is connected to the chimney 6. The deodorization unit is used to treat the odor generated by the composting reactor 1. The ammonia recovery unit is connected to the deodorization unit and is used to recover ammonia from the deodorized wastewater generated by the deodorization unit.

[0031] The deodorization unit includes a three-stage spray deodorization device, a heat exchange device, and a blower 2. The three-stage spray deodorization device includes a first-stage spray tower 3, a second-stage spray tower 4, and a third-stage spray tower 5 connected sequentially by pipes. The air outlet at the top of the composting reactor 1 is connected to the air inlet at the bottom of the first-stage spray tower 3 via a pipe equipped with the blower 2. The air outlet at the top of the third-stage spray tower 5 is connected to a chimney 6 via a pipe. Specifically, the composting reactor 1 is a vertical closed composting reactor, and the blower 2 is a centrifugal blower. The top of the composting reactor 1 is equipped with an odor emission pipe, which is connected to the air inlet of the blower 2. The air outlet of the blower 2 is connected to the bottom of the first-stage spray tower 3 via a pipe. The top of the first-stage spray tower 3 is connected to the bottom of the second-stage spray tower 4 via a pipe. The top of the second-stage spray tower 4 is connected to the bottom of the third-stage spray tower 5 via a pipe. The purified gas is then discharged from the top of the third-stage spray tower 5 through the chimney 6. The multi-stage spray tower consists of three stages connected in series. The fan 2 provides power, and the odorous gas is purified by passing through the three spray towers in sequence before being discharged from the top of the third spray tower 5 through the chimney 6 in compliance with standards.

[0032] The first-stage spray tower 3, the second-stage spray tower 4, and the third-stage spray tower 5 are equipped with a spraying mechanism, a packing layer 9, and a bottom water tank 10, arranged sequentially from top to bottom. The spraying mechanism includes spray pipes 7 and nozzles 8, with the nozzles 8 mounted on the spray pipes 7. Specifically, there are two layers of packing layer 9, with a spraying mechanism installed above each layer. The multi-stage spray towers are connected in series. Odors sequentially enter the first, second, and third-stage spray towers, where ammonia and other odors are absorbed and then enter the spray water. The water in the bottom water tank 10 of the three-stage spray towers comes into full contact with the odors in the packing layer 9 through counter-current flow, absorbing the ammonia and other odors.

[0033] The heat exchange device is connected to the first-stage spray tower 3 via a pipeline. Specifically, the water tank 10 at the bottom of the first-stage spray tower 3 is connected to the heat exchange device via a pipeline. After exchanging with the odorous gas, the first-stage spray tower 3 becomes hot water that has absorbed odorous gases such as ammonia. This hot water enters the heat exchange device through a pipeline. The heat exchange device is used to cool the water in the first-stage spray tower 3. Only the first-stage spray tower 3 has the highest heat exchange efficiency. By setting up the heat exchange device, the absorption of odorous gases such as ammonia can be more efficient when the odorous gas and water exchange countercurrently in the packing layer 9 of the spray tower, that is, ammonia can be fully and efficiently absorbed from the odorous gas.

[0034] The heat exchange device includes a plate heat exchanger 11 and an air-cooled tower 12. The plate heat exchanger 11 is equipped with a first hot water pipe 13, a second hot water pipe 14, a first cold water pipe 15, and a second cold water pipe 16. Hot water from the water tank 10 at the bottom of the first-stage spray tower 3 enters the hot water plate of the plate heat exchanger 11 through the first hot water pipe 13. The plate heat exchanger 11 and the air-cooled tower 12 are connected through the second hot water pipe 14 and the second cold water pipe 16. Cooling water from the air-cooled tower 12 enters the cold water plate of the plate heat exchanger 11 through the second cold water pipe 16. Hot water and cooling water exchange heat in the plate heat exchanger 11 in a non-direct contact manner between the hot water plate and the cold water plate. The cooled hot water enters the first cold water pipe 15, which is connected to the spray pipe 7 of the first-stage spray tower 3. The heated cooling water enters the second hot water pipe 14 and flows back into the air-cooled tower 12.

[0035] The bottom water tank 10 of the first-stage spray tower 3 is connected to the plate heat exchanger 11 through the first hot water pipe 13. After non-contact heat exchange with the cooling water in the plate heat exchanger 11, the first cold water pipe 15 on the plate heat exchanger 11 is connected to the spray pipe 7 of the first-stage spray tower 3. The spray pipes 7 of the second-stage spray tower 4 and the third-stage spray tower 5 are respectively connected to the bottom water tank 10 of the second-stage spray tower 4 and the third-stage spray tower 5 through pipes. Specifically, the hot water from the bottom water tank 10 of the first-stage spray tower 3 enters the first hot water pipe 13 of the plate heat exchanger 11, and the cooling water from the bottom of the air-cooled tower 12 enters the second cold water pipe 16 of the plate heat exchanger 11. The hot water and cooling water exchange heat through non-contact heat exchange. The heated cooling water returns to the air-cooled tower 12 for air cooling, and the cooled spray water returns to the first-stage spray tower 3 to continue to efficiently and fully absorb ammonia from the compost odor. This cycle continues until the spray water is saturated with ammonia. Only then is the water in the bottom water tank 10 of the third-stage spray tower pumped into the ammonia recovery unit, and the water in the bottom water tank 10 of the third-stage spray tower replaced with new tap water or purified water.

[0036] The ammonia recovery unit includes a water collection tank 17, a preheater 18, a distillation column 19, a cooling device, and an ammonia tank 25. The water collection tank 17 collects deodorization wastewater generated by the deodorization unit. The outlet of the water collection tank 17 is connected to the first inlet of the preheater 18. The outlet of the preheater 18 is connected to the middle inlet of the distillation column 19. The bottom outlet of the distillation column 19 is connected to the second inlet of the preheater 18. The top outlet of the distillation column 19 is connected to the inlet of the cooling device, and the outlet of the cooling device is connected to the ammonia tank 25. The ammonia recovery unit also includes a reboiler 20, which is located next to the distillation column 19 and connected to it. The reboiler 20 provides a heat source for the distillation column 19. The ammonia recovery unit also includes a purified water tank 21, whose inlet is connected to the bottom outlet of the distillation column 19. Specifically, the cooling device includes a first-stage cooler 22, a reflux tank 23, and a second-stage cooler 24. The inlet of the first-stage cooler 22 is connected to the top outlet of the distillation column 19, the first outlet of the first-stage cooler 22 is connected to the top inlet of the reflux tank 23, the bottom outlet of the reflux tank 23 is connected to the upper inlet of the distillation column 19, the second outlet of the first-stage cooler 22 is connected to the inlet of the second-stage cooler 24, and the outlet of the second-stage cooler 24 is connected to the ammonia tank 25.

[0037] In this embodiment, the bottom water tanks 10 of the first-stage spray tower 3, the second-stage spray tower 4, and the third-stage spray tower 5 are connected to the inlet of the water collection tank 17 via pipes. The outlet of the purified water tank 21 is connected to the bottom water tanks 10 of the first-stage spray tower 3, the second-stage spray tower 4, and the third-stage spray tower 5 via pipes. The collection tank 17 is used to collect and store the hot deodorizing wastewater that has absorbed ammonia from the three-stage spray tower. The deodorizing wastewater in the collection tank 17 is first pumped into the preheater 18 by a water pump. The preheater 18 is used to preheat the deodorizing wastewater in the collection tank 17 to 80-90℃. The heat source of the preheater 18 comes from the hot water at the bottom of the distillation column 19 after ammonia stripping. The deodorizing wastewater and the hot water at the bottom of the distillation column 19 undergo non-contact heat exchange in the preheater 18 to achieve the preheating of the deodorizing wastewater. The preheated deodorizing wastewater is then sprayed into the middle of the distillation column 19 by a pump to ensure the temperature balance inside the distillation column 19. A reboiler 20 is located next to the bottom of the distillation column 19. The reboiler 20 is used to heat the distillation column 19. The heat transfer oil inside the reboiler 20 is connected to the heat transfer oil pipeline outside the distillation column 19 and circulates continuously, keeping the temperature inside the distillation column 19 at the set temperature (100℃). The continuous high temperature environment ensures that ammonia is efficiently distilled from the wastewater as the deodorizing wastewater is sprayed into the distillation column 19 from the middle. The distilled high ammonia gas enters the top of the distillation column 19 with the hot steam and continues to enter the first-stage cooler 22 for condensation. The purified water after the ammonia is distilled flows back to the bottom of the distillation column 19 and is periodically pumped into the purified water pool 21 by the water pump at the bottom of the distillation column 19. Part of it is used for the deodorization water of the three-stage spray tower, and part of it is discharged in compliance with standards or used for resource utilization. The first-stage cooler 22 uses a water pump to supply external low-temperature water and ammonia vapor for non-contact gas-liquid heat exchange to achieve first-stage condensation. The condensed liquid containing ammonia water enters the reflux tank 23, which is then pumped back to the top of the distillation column 19 by the reflux pump 30 for further ammonia distillation and concentration. The high-concentration ammonia gas that is not condensed continues to enter the second-stage cooler 24, where it undergoes non-contact heat exchange with external low-temperature water. The condensed ammonia water reaches the set concentration and is stored in the ammonia water tank 25.

[0038] The working principle of this deodorization unit is as follows: The odor emission pipe at the top of the composting reactor 1 is connected to one end of the blower 2. The blower 2 collects the odor emitted from the composting reactor 1. The other end of the blower 2 is connected to the lower part of the first-stage spray tower 3 (above the water level of the bottom water tank 10) through a pipe, concentrating the odor to be transported to the third-stage spray tower. In the two layers of packing 9 of the third-stage spray tower, the odor undergoes counter-current gas-liquid exchange and heat exchange with the spray water, and is then discharged from the top pipe of the first-stage spray tower 3. The third-stage spray tower consists of three spray towers connected in series. The blower 2 provides power, and the gas enters the second and third-stage spray towers through the pipes to fully absorb the ammonia and other odors and heat into the spray water. The deodorized gas is discharged through the top of the third-stage spray tower 5, meeting the emission standards. The spray water then becomes hot water that has absorbed the odor. The deodorized hot water in the bottom water tank 10 of the first-stage spray tower 3 is then discharged through the first heat tank 5. Water pipe 13 is connected to plate heat exchanger 11, and plate heat exchanger 11 is connected to air-cooled tower 12 through second cold water pipe 16. The deodorizing hot water of first-stage spray tower 3 and the cold water of air-cooled tower 12 undergo non-contact heat exchange in plate heat exchanger 11, realizing the cooling of deodorizing hot water and the heating of cooling water in first-stage spray tower 3. The heated cooling water returns to air-cooled tower 12 through second hot water pipe 14 for continuous cooling, while the cooled spray water is powered by circulating water pump 26 to return to first-stage spray tower 3 through first cold water pipe 15 to continuously absorb odors such as ammonia into the spray water until the spray water is saturated with ammonia. Then, the deodorizing wastewater in the bottom water tank 10 of the third-stage spray tower is pumped into the collection pool 17 in the ammonia recovery unit for treatment through drainage pump 27. At the same time, the water in the bottom water tanks 10 of the three spray towers is replaced with new tap water or purified water for reuse.

[0039] The working principle of this ammonia recovery unit is as follows: The deodorized wastewater from the bottom water tank 10 of the three-stage spray tower is pumped into the collection tank 17 via the drain pump 27. The wastewater in the collection tank 17 is then pumped into the preheater 18 via the inlet pump 28. The heat source for the preheater 18 is the heated purified water at the bottom of the distillation column 19. The deodorized wastewater and the hot water pumped from the bottom of the distillation column 19 undergo non-contact heat exchange within the preheater 18. The deodorized wastewater is preheated to 80-90℃ in the preheater 18, and then sprayed into the middle of the distillation column 19 through pipes and nozzles. Next to the bottom of the distillation column 19 is a reboiler 20, which is used to heat the distillation column 19. The heat transfer oil inside the reboiler 20 is connected to the heat transfer oil outside the distillation column 19. The system continuously circulates internally, maintaining the temperature inside the distillation column 19 at the set temperature (100℃). The consistently high temperature environment inside the distillation column 19 ensures that ammonia is efficiently distilled from the wastewater as the deodorizing wastewater is sprayed down from the middle of the distillation column 19. The distilled high-ammonia gas enters the top of the distillation column 19 with the hot steam and continues to enter the first-stage cooler 22 for condensation. The purified water after the ammonia has been distilled flows back to the bottom of the distillation column 19 and is periodically discharged into the purified water tank 21 through a valve at the bottom of the distillation column 19. The purified water in the purified water tank 21 can be partially used for deodorization water in the third-stage spray tower (pumped back to the bottom water tank 10 of the third-stage spray tower by the return water pump 29 through the pipeline), partially discharged in compliance with standards, or used for resource utilization. The first-stage cooler 22 is connected to the top of the distillation column 19. The first-stage cooler 22 uses a water pump to provide external low-temperature water for non-contact heat exchange with the distilled ammonia vapor to achieve first-stage condensation. Some of the ammonia vapor is condensed into a liquid containing ammonia water and enters the reflux tank 23. The reflux tank 23 then uses the reflux pump 30 to pump it back to the top of the distillation column 19 to continue distilling ammonia and further concentrate the ammonia. The high-concentration ammonia vapor that is not condensed continues to enter the second-stage cooler 24 and undergoes non-contact heat exchange with external low-temperature water in the second-stage cooler 24, so that the ammonia water that reaches the set concentration is condensed and stored in the ammonia water tank 25.

[0040] In summary, this utility model provides an ammonia recovery deodorization system for composting reactors. It recovers ammonia from the high-temperature, high-humidity odorous gases in a closed composting reactor, combining distillation technology with the purification of deodorized wastewater generated from odor treatment. This deodorization system addresses the pain point of ammonia emission reduction in the livestock and poultry farming industry, breaking through the industry's conventional approach of "biological denitrification—nitrogen treatment—no environmental pollution." Without affecting the normal operation of the composting reactor's harmless treatment of livestock and poultry manure, it applies distillation technology to the purification of deodorized wastewater, simultaneously recovering ammonia from the odorous gases as ammonia water, generating revenue that subsequently reduces the deodorization costs of the composting reactor. Composting reactors produce high-ammonia odor during the harmless treatment of livestock and poultry manure, necessitating odor control. This odor purification process inevitably generates deodorization wastewater, which is characterized by low carbon content and high ammonia levels. Direct biological denitrification for ammonia removal is costly due to high equipment investment and processing fees. Therefore, this paper introduces distillation technology to recover ammonia from the deodorization wastewater, simultaneously purifying the wastewater. This fully embodies the technical characteristics of synergistic treatment, achieving "harmless solid waste treatment—odor gas removal—purification of deodorization-derived wastewater—ammonia recovery and reuse." The recovered ammonia water is used for added value, reducing deodorization costs, achieving full resource recycling of nutrients, and completely eliminating secondary pollution problems. Most importantly, this technology can be extended to all solid wastes, such as garbage, treated harmlessly using closed composting reactors, with a very broad market application prospect and demand. Meanwhile, the high ammonia water with a concentration greater than 12% after distillation and condensation can be used as a raw material for liquid fertilizer or directly as a chemical raw material. Selling it can generate certain revenue, which in turn greatly reduces the deodorization cost of the reactor. This deodorization system has great social, environmental and even economic benefits, and is in line with the national concepts of pollution reduction, carbon reduction and resource recycling.

Claims

1. A deodorization system with ammonia recovery for a composting reactor, characterized in that, include: The deodorization unit has an air inlet connected to the air outlet of the composting reactor (1) and an air outlet connected to the chimney (6). The deodorization unit is used to treat the odor generated by the composting reactor (1). An ammonia recovery unit is connected to a deodorization unit. The ammonia recovery unit is used to recover ammonia from the deodorization wastewater generated by the deodorization unit. The ammonia recovery unit includes a water collection tank (17), a preheater (18), a distillation column (19), a cooling device, and an ammonia tank (25). The water collection tank (17) is used to collect the deodorization wastewater generated by the deodorization unit. The outlet of the water collection tank (17) is connected to the first inlet of the preheater (18). The outlet of the preheater (18) is connected to the middle inlet of the distillation column (19). The bottom outlet of the distillation column (19) is connected to the second inlet of the preheater (18). The top outlet of the distillation column (19) is connected to the inlet of the cooling device. The outlet of the cooling device is connected to the ammonia tank (25).

2. The deodorization system with ammonia recovery for a compost reactor according to claim 1, characterized in that, The cooling device includes a first-stage cooler (22), a reflux tank (23), and a second-stage cooler (24). The inlet of the first-stage cooler (22) is connected to the top outlet of the distillation column (19). The first outlet of the first-stage cooler (22) is connected to the top inlet of the reflux tank (23). The bottom outlet of the reflux tank (23) is connected to the upper inlet of the distillation column (19). The second outlet of the first-stage cooler (22) is connected to the inlet of the second-stage cooler (24). The outlet of the second-stage cooler (24) is connected to the ammonia tank (25).

3. The deodorization system with ammonia recovery for a compost reactor according to claim 1, characterized in that, The ammonia recovery unit also includes a reboiler (20), which is located next to the distillation column (19) and is used to provide a heat source for the distillation column (19).

4. The deodorization system with ammonia recovery for a compost reactor according to claim 1, characterized in that, The ammonia recovery unit also includes a purification water tank (21), the inlet of which is connected to the bottom outlet of the distillation column (19).

5. The deodorization system with ammonia recovery for a compost reactor according to claim 4, characterized in that, The deodorization unit includes a three-stage spray deodorization device, a heat exchange device, and a fan (2). The three-stage spray deodorization device includes a first-stage spray tower (3), a second-stage spray tower (4), and a third-stage spray tower (5) connected in sequence by pipes. The heat exchange device is connected to the first-stage spray tower (3) by a pipe. The air outlet at the top of the composting reactor (1) is connected to the air inlet at the bottom of the first-stage spray tower (3) by a pipe equipped with a fan (2). The air outlet at the top of the third-stage spray tower (5) is connected to the chimney (6) by a pipe.

6. The deodorization system with ammonia recovery for a compost reactor according to claim 5, characterized in that, The first-stage spray tower (3), the second-stage spray tower (4) and the third-stage spray tower (5) are equipped with a spraying mechanism, a packing layer (9) and a bottom water tank (10) from top to bottom.

7. The deodorization system with ammonia recovery for a compost reactor according to claim 6, characterized in that, The spraying mechanism includes a spray pipe (7) and a nozzle (8), with the nozzle (8) disposed on the spray pipe (7).

8. The deodorization system with ammonia recovery for a compost reactor according to claim 7, characterized in that, The heat exchange device includes a plate heat exchanger (11) and an air-cooled tower (12). The plate heat exchanger (11) is provided with a first hot water pipe (13), a second hot water pipe (14), a first cold water pipe (15), and a second cold water pipe (16). Hot water from the water tank (10) at the bottom of the first-stage spray tower (3) enters the first hot water pipe (13). The plate heat exchanger (11) and the air-cooled tower (12) are connected through the second hot water pipe (14). Cooling water from the air-cooled tower (12) enters the second cold water pipe (16). The first cold water pipe (15) is connected to the spray pipe (7) of the first-stage spray tower (3).

9. The deodorization system with ammonia recovery for a compost reactor according to claim 8, characterized in that, The bottom water tank (10) of the first-stage spray tower (3) is connected to the plate heat exchanger (11) through the first hot water pipe (13). After exchanging heat with the plate heat exchanger (11), the first cold water pipe (15) on the plate heat exchanger (11) is connected to the spray pipe (7) of the first-stage spray tower (3). The spray pipes (7) of the second-stage spray tower (4) and the third-stage spray tower (5) are respectively connected to the bottom water tank (10) of the second-stage spray tower (4) and the third-stage spray tower (5) through pipes.

10. The deodorization system with ammonia recovery for a compost reactor according to claim 6, characterized in that, The bottom water tanks (10) of the first-stage spray tower (3), the second-stage spray tower (4) and the third-stage spray tower (5) are connected to the inlet of the water collection pool (17) through pipes, and the outlet of the purification pool (21) is connected to the bottom water tanks (10) of the first-stage spray tower (3), the second-stage spray tower (4) and the third-stage spray tower (5) through pipes.

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