Resource recycling method and system for ammonia-containing gas

Abstract

The invention discloses a resource recycling method and system for ammonia-containing gas, and the method comprises the following steps: firstly, introducing the ammonia-containing gas into a gas-liquid separation pretreatment area at the bottom of a device, and carrying out step-by-step gas-liquid separation and impurity purification through a horizontal spiral channel disc, a wire mesh demister and an iron oxide absorption layer; the purified gas enters an ammonia gas absorption reaction area in the middle and is subjected to countercurrent contact reaction with absorption liquid in a filler layer; the generated ammonium salt recovery liquid is pumped into an ammonium salt crystallization area at the top under the regulation and control of an automatic control system, and an ammonium salt crystal product is finally obtained through evaporation concentration, gradient crystallization and vibration screening; the method is realized by a system integrating three functional areas of gas-liquid separation, ammonia gas absorption and evaporative crystallization. According to the invention, efficient absorption of ammonia components in ammonia-containing gas and resource recovery of ammonium salt products are realized, and the method has the advantages of compact process and high operation automation degree.

Description

Technical Field

[0001] This invention belongs to the field of industrial waste gas treatment and resource recovery technology, specifically relating to a method and system for the resource recovery of ammonia-containing gas. Background Technology

[0002] Large quantities of high-concentration ammonia nitrogen wastewater or ammonia-containing waste gas are generated during fertilizer production, livestock farming, landfill leachate treatment, and certain chemical production processes. Direct discharge of ammonia nitrogen will lead to eutrophication of water bodies or air pollution, posing a serious threat to ecosystems. Meanwhile, ammonia itself is also a valuable resource. Therefore, the efficient treatment and resource recovery of ammonia-containing waste is of great significance.

[0003] For high-concentration ammonia nitrogen wastewater, stripping is a widely used pretreatment technology. This method separates the wastewater by adjusting the pH and converting ammonium salts into ammonia gas. The ammonia-containing stripping gas generated in this process, which is high-temperature, high-humidity, and often contains impurities such as hydrogen sulfide, is a typical and challenging type of waste gas to be treated in this invention. However, the stripping process only achieves the transfer of pollutants from the liquid phase to the gas phase. If this gas is not properly treated, it will cause secondary pollution and waste of resources.

[0004] To recover ammonia from ammonia-containing gases (taking stripping gas as an example), absorption is a common post-treatment method. Traditional absorption processes typically employ a multi-tower series configuration, where the gas first passes through pretreatment towers such as gas-liquid separation and washing towers before entering the absorption tower to react with absorbents such as sulfuric acid to generate an ammonium sulfate solution. This multi-tower series process is lengthy, requires a large equipment footprint, and incurs high initial investment and operating costs. Furthermore, the resulting ammonium sulfate solution has a low concentration; further resource recovery to produce solid ammonium sulfate products necessitates the introduction of an additional, energy-intensive evaporation and crystallization system.

[0005] Chinese patent publication CN217025649U discloses a novel stripping device. The system includes multiple independent components such as a water collection tank, regulating tank, sand filter, oil-water separator, steam riser, stripping tower, extraction pump, tail gas absorption tower, and reagent pump, all connected sequentially via pipelines. While this solution achieves stripping and absorption, the system is large, the process is complex, and the equipment is dispersed. Furthermore, its product is an ammonium sulfate solution, failing to address the high energy consumption issue of subsequent conversion of the solution into a solid product. Another patent, CN102060406A, discloses an integrated process for efficient stripping and tail gas ammonia resource recovery. It achieves process enhancement and integration through optimization of tower internals and absorbent liquid. However, its resource recovery product is concentrated ammonia water with a concentration of 10wt%~25wt%, failing to extend to directly usable solid ammonium sulfate crystals. The resource recovery depth is insufficient, and crystallization still relies on an external system.

[0006] In summary, existing ammonia-containing gas (especially stripping gas) recovery systems generally suffer from problems such as dispersed equipment, lengthy processes, low integration, incomplete resource recovery due to the inability to integrate low-energy crystallization units, and poor economic efficiency for small- and medium-scale applications. Therefore, developing an integrated system that can highly integrate the purification, absorption, and crystallization processes of ammonia-containing gas to achieve efficient and low-cost ammonia resource recovery is particularly urgent, and this is precisely the technical problem that this invention aims to solve. Summary of the Invention

[0007] The purpose of this invention is to provide a method and system for the resource recovery of ammonia-containing gas, so as to solve the problems of incomplete resource recovery caused by the dispersed equipment, lengthy process, low integration and high energy consumption of crystallization in existing ammonia recovery technologies.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: According to one aspect of the present invention, a method for resource recovery of ammonia-containing gas is provided, the method comprising the following steps: Step (1): Ammonia-containing gas first enters the gas-liquid separation pretreatment zone, undergoes centrifugal separation through a horizontally set spiral channel disk, then undergoes deep demisting through a wire mesh demister, and finally passes through an impurity gas absorption layer to remove hydrogen sulfide impurity gas, thus completing the gas purification.

[0009] Step (2): The purified gas enters the ammonia absorption reaction zone and reacts countercurrently with the absorbent sprayed from top to bottom in the packing layer to generate ammonium salt recovery liquid. Step (3): The absorbent stored in the storage tank of the ammonia absorption reaction zone is automatically controlled by a pH meter and a level gauge, which links the circulation pump, crystallization pump and acid replenishment pump to realize the circulation absorption of the absorbent, the automatic delivery of qualified product liquid and the precise replenishment of absorbent.

[0010] Step (4): The ammonium salt recovery liquid from step (3) is transported to the evaporation crystallization zone. It is first concentrated by evaporation on a rotating conical surface, then crystals grow and are graded on a multi-temperature annular crystallization surface. After that, solid-liquid separation is carried out by a vibrating sieve drying unit to finally obtain ammonium sulfate crystal products. The separated mother liquor is returned to the system for circulation and concentration. When the density of the solution in the mother liquor tank is detected to be greater than the upper limit, the mother liquor return pump is started to return the mother liquor to the absorption zone to prevent excessive accumulation of crystals in the mother liquor tank.

[0011] In one embodiment, in step (1), the ammonia-containing gas undergoes preliminary gas-liquid separation through a horizontally arranged spiral channel disk, which, combined with deep separation by a two-layer wire mesh demister, can further improve the gas-liquid separation efficiency while saving energy.

[0012] In one embodiment, the gas-liquid flow direction is opposite in step (2), which accelerates the absorption liquid and mass transfer process, thereby improving the ammonia absorption efficiency. The packing layer packing can be reused.

[0013] In one embodiment, the linkage logic of the circulation pump, crystallization pump, and acid replenishment pump in step (3) is as follows: When the liquid level in the storage tank reaches 70% of its volume, the circulation pump starts to transport the liquid in the storage tank to the absorbent distribution pipe above the packing layer for spraying. When the pH value is greater than 5 and lasts for more than 30 seconds, and the liquid level is higher than 65% of its volume, the crystallization pump starts to send the liquid in the storage tank to the evaporation and crystallization zone until the liquid level drops to 40%. If the pH value fluctuates beyond 5.8 while the crystallization pump is running, the acid replenishment pump will be activated to replenish a small amount of acid. After the crystallization pump stops running, the acid replenishment pump will be activated to fill the storage tank to 70% capacity. This multi-stage equipment linkage reduces excessive process steps and further improves the level of integration.

[0014] In one embodiment, the rotary concentration unit described in step (4) operates at a temperature range of 30-60°C. The multi-temperature zone annular crystallization surface is divided into three temperature zones along the material flow direction: a primary temperature zone connected to the conical surface, with a temperature range of 35-50°C; a secondary temperature zone in the middle, with a temperature range of 30-45°C; and a tertiary temperature zone at the outlet, with a temperature range of 25-35°C. The starting logic of the mother liquor reflux pump is as follows: when the density of the mother liquor in the mother liquor tank is greater than 1.2 g / cm³... 3 At that time, the reflux pump starts to transport the liquid in the mother liquor tank to the storage tank in the ammonia absorption reaction zone.

[0015] According to another aspect of the present invention, a resource recovery system for ammonia-containing gas is provided, the system comprising, from bottom to top, a gas-liquid separation pretreatment zone, an ammonia absorption reaction zone, and an evaporation crystallization zone.

[0016] The gas-liquid separation pretreatment zone includes an air inlet on the outer wall, a horizontally arranged spiral channel disc and a gas distributor on top of it, a wire mesh demister above it, an impurity gas absorption layer, and an air outlet on the top side.

[0017] The ammonia absorption reaction zone includes a storage tank, an air inlet located on the side wall of the storage tank, which is connected to the air outlet of the pretreatment zone via a pipe, a packing layer above the storage tank, a circulation pump for transporting the liquid in the storage tank to the absorbent distribution pipe above the packing layer, the system also includes a pH and liquid level monitoring device for the storage tank, a crystallization device for pumping the liquid to the evaporation crystallization zone, an acid replenishment pump for replenishing the storage tank, an exhaust port on the top side, and a reflux inlet.

[0018] The evaporation crystallization zone includes a rotary concentration unit, a multi-temperature zone annular crystallization surface connected to the rotary concentration unit, a vibrating sieve drying unit located below the annular crystallization surface, and a mother liquor tank and a crystal collection box located below it. The mother liquor tank is connected to a mother liquor circulation pump, a mother liquor reflux pump, and a crystallization pump in the ammonia absorption reaction zone via pipelines. A density meter is installed in the mother liquor tank.

[0019] In one embodiment, the bottom of the spiral channel disk of the gas-liquid separation pretreatment zone is an upwardly convex curved surface, and a gas distributor is installed at the center of its top sealing cap.

[0020] In one embodiment, the packing layer of the ammonia absorption reaction zone includes, but is not limited to, Raschig rings, Pall rings, stepped rings, arc saddle packing, rectangular saddle packing, ring-rectangular saddle, and spherical packing.

[0021] In one embodiment, the rotary concentration unit of the evaporation crystallization zone is a conical surface with dotted protrusions. The surface of its multi-temperature zone annular crystallization surface is provided with square grooves. The grooves are 2 mm deep and 2.4-3 mm wide, and the annular crystallization surface is generally inclined at an angle of 3-5°. The vibrating sieve drying unit (303) is equipped with a horizontal reciprocating vibration mechanism and a fan.

[0022] In one embodiment, the system is further equipped with a cleaning system, which is connected in parallel with the circulation pump via an externally heated water pump and pipes, for rinsing the equipment surface within the evaporation and crystallization zone.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. High integration and miniaturization: The gas-liquid separation, chemical absorption, evaporation and crystallization processes are integrated into a single tower body. The equipment is compact and occupies a small area, making it particularly suitable for small and medium-sized application scenarios.

[0024] 2. Full-process automation: Through the intelligent linkage between the pump set and online monitoring instruments, the entire process from absorption reaction to crystal production is automatically controlled, which is simple to operate and stable in operation.

[0025] 3. Thorough resource utilization and low energy consumption: It realizes the direct conversion from waste gas to high-purity solid products, with a high degree of resource utilization; the integrated crystallization process adopted significantly reduces energy consumption compared with traditional MVR and other systems.

[0026] The system operates stably and reliably: by monitoring the concentration of the mother liquor with a densitometer and controlling the reflux, crystal enrichment is effectively prevented, ensuring the long-term stable operation of the crystallization process. Attached Figure Description

[0027] Figure 1 This is a process flow diagram of the resource recovery method for ammonia-containing gas in an embodiment of the present invention; Figure 2 This is a schematic diagram of an ammonia-containing gas resource recovery system in an embodiment of the present invention; In the diagram: 1-Gas-liquid separation pretreatment zone; 2-Ammonia absorption reaction zone; 3-Evaporation and crystallization zone; 101-Outer wall gas inlet. 102-Spiral channel plate; 103-Gas distributor; 104-Wire mesh demister; 105-Impurity gas absorption layer; 106-Gas outlet; 201-Liquid storage tank; 202-Air inlet; 203-Packaging layer; 204-Absorbent liquid distribution pipe; 205-Circulation pump; 206-pH meter; 207-Level gauge; 208-Crystallization pump; 209-Acid replenishment pump; 210-Reflux liquid inlet; 211-Tail gas outlet; 301-Rotary concentration unit; 302-Multi-temperature zone annular crystallization surface; 303-Vibrating sieve drying unit; 304-Mother liquor tank; 305-Crystal collection box; 306-Mother liquor circulation pump; 307-Mother liquor reflux pump; 308-Density meter; 30-Liquid inlet; 310-Gas pore. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. This embodiment takes the treatment of ammonia-containing stripping gas from a landfill leachate treatment plant as an example to specifically illustrate the implementation process of the present invention.

[0029] Device startup and operation: The ammonia-containing gas resource recovery system is put into operation. First, the acid replenishment pump (209) is turned on to deliver a 10-15% concentration of dilute sulfuric acid solution to the storage tank (201) in the ammonia absorption reaction zone (2). When the level gauge (207) detects that the liquid level in the storage tank reaches 70% of the total volume, the acid replenishment pump (209) automatically stops. Then, the circulation pump (205) is started to pump the dilute sulfuric acid in the storage tank into the absorbent distribution pipe (204) above the packing layer, so that it is sprayed down evenly.

[0030] At this time, the ammonia-containing stripping gas, with a temperature of 50-60℃ and containing water vapor and trace amounts of hydrogen sulfide, enters the gas-liquid separation pretreatment zone (1) from the outer wall inlet (101) at the bottom of the device at a certain flow rate. The gas first enters the horizontally arranged spiral channel disk (102) tangentially. Under the action of centrifugal force, most of the liquid droplets are thrown to the channel wall. Since the bottom of the disk is a slightly upward convex curved surface, the separated liquid is collected along the wall to the outermost circle of the spiral channel under the action of gravity, and is finally discharged from the system as waste liquid. The gas after preliminary dehydration flows upward, first passing through the double-layer wire mesh demister (104) for deep demisting, and then passing through the impurity gas absorption layer (105) to remove hydrogen sulfide impurities, completing the purification of the gas and flowing out from the top outlet.

[0031] The purified gas flows out from the outlet (106) and enters through a pipe connected to the inlet (202) of the ammonia absorption reaction zone (2). It then undergoes a full countercurrent reaction in the packing layer (203) with the absorption liquid, which is pumped into the distribution pipe (204) by the circulating pump (205) and flows downwards, to generate an ammonium sulfate solution. Excess gas is discharged through the tail gas port (211) on the top side of this area, and the liquid after absorption flows back to the storage tank (201) by gravity. As the reaction proceeds, the concentration of the ammonium sulfate solution in the storage tank continuously increases, and the pH value of the solution rises accordingly.

[0032] When the pH meter (206) in the storage tank detects a pH value greater than 5 for more than 30 seconds, and the level gauge (207) shows a level higher than 65% of the volume, the crystallization pump (208) automatically starts, pumping the qualified ammonium salt recovery solution into the top evaporation crystallization zone (3) through the inlet (309). The pumping process continues until the storage tank level drops to 40%. During the operation of the crystallization pump, the circulation pump (205) continues to work to ensure the absorption reaction proceeds. If the pH rises above 5.8 due to violent reaction fluctuations, the acid replenishment pump (209) will start slightly to precisely replenish the acid. After the crystallization pump stops, the acid replenishment pump (209) will restart to replenish the storage tank level to 70% to prepare for the next absorption-transport cycle.

[0033] After entering the evaporation crystallization zone, the ammonium sulfate solution is first conveyed to the conical surface of the rotary concentration unit (301). This conical surface is heated to 50°C, and the solution forms a thin layer under the action of centrifugal force, rapidly evaporating the water and achieving initial concentration. Water vapor is discharged through the pores (310) at the top of the crystallization zone, and then the solution flows into the multi-temperature zone annular crystallization surface (302) below it. This annular surface is radially divided into three temperature zones: the outer ring inlet zone has a temperature of 42°C, the middle ring growth zone has a temperature of 37°C, and the inner ring outlet zone has a temperature of 32°C. During the flow of the solution through this gradient temperature zone, supersaturation is precisely controlled, and ammonium sulfate crystals continuously precipitate and grow. The annular crystallization surface is provided with square grooves 2 mm deep and 3 mm wide, with a 3° tilt angle, which can both briefly trap tiny seed crystals and ensure the smooth sliding out of mature crystals.

[0034] The mother liquor carrying the crystals eventually falls into the vibrating sieve drying unit (303). This unit, through the combined action of a horizontal reciprocating vibration mechanism and a side fan, achieves the separation of crystals from the mother liquor and the initial drying of the crystal surface. The dried ammonium sulfate crystals fall into a crystal collection box (305) for collection. The separated mother liquor enters a mother liquor tank (304). As a preferred embodiment, a movable rigid filter basket can be placed inside the crystal collection box (305) and the mother liquor tank (304). This filter basket, acting as a liftable "inner liner," effectively intercepts crystals, facilitating their centralized removal and cleaning, while preventing crystal accumulation at the bottom of the tank.

[0035] The mother liquor circulation pump (306) pumps the mother liquor in the mother liquor tank back into the rotary concentration unit (301) for circulation concentration, so as to continuously increase the supersaturation of the mother liquor, promote the continuous precipitation of ammonium sulfate crystals, and thus increase the crystal yield.

[0036] When the densitometer (308) installed in the mother liquor tank detects that the solution density has reached the preset upper limit (1.2 g / cm³), the mother liquor return pump (307) automatically starts. At the same time, the hot water pump connected in parallel with the mother liquor circulation pump (306) starts synchronously to clean the entire circulation system. The mother liquor return pump (307) pumps this high-concentration mother liquor back to the storage tank (201) in the ammonia absorption reaction zone (2). The core purpose of this operation is to actively reduce the concentration of the mother liquor in the crystallization system, fundamentally preventing the spontaneous precipitation and blockage of crystals in pipes, pumps, etc. due to excessive supersaturation, thereby ensuring that the device can achieve long-term, stable, and continuous operation. The external hot water pump pumps hot water into the evaporation crystallization zone (3) to circulate and rinse the rotating cone surface, the annular crystallization surface, and the vibrating screen. This process lasts for about 2 cycles, aiming to thoroughly prevent crystals from scaling and clogging the equipment surface. Finally, the liquid in the mother liquor tank (304) is completely drained, completing a complete cleaning and reset cycle.

[0037] As a preferred embodiment, in order to obtain crystal products with more uniform particle size, after the system is running stably, a small amount (e.g., 0.1%-0.5% of the feed amount) of seed solution containing ammonium sulfate microcrystals with a particle size of 100-200 mesh can be continuously added to the system by means of a parallel pipe connected to the mother liquor circulation pump (306).

[0038] The above description of the embodiments is provided to enable those skilled in the art to understand the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for the resource recovery of ammonia-containing gas, characterized in that, Includes the following steps: (1) The ammonia-containing gas first enters the gas-liquid separation pretreatment zone, and after centrifugal separation by a horizontally set spiral channel disk, it undergoes deep demisting by a wire mesh demister, and finally the impurity gas absorption layer removes the impurities, thus completing the gas purification. (2) The purified gas enters the ammonia absorption reaction zone and reacts with the absorption liquid that is pumped from the storage tank into the absorption liquid distribution pipe by the circulating pump in the packing layer to the ammonium salt recovery liquid. (3) When the ammonium salt recovery liquid stored in the storage tank of the ammonia absorption reaction zone reaches a certain pH value and liquid level and lasts for a certain period of time, it is transported to the evaporation crystallization zone by the crystallization pump through the pipeline. When the liquid level of the storage tank drops to a certain range, the acid replenishment pump is started to replenish acid. (4) In the evaporation and crystallization zone, the ammonium salt recovery liquid is concentrated by evaporation on a rotating conical surface, and then crystals are grown and graded on a multi-temperature zone annular crystallization surface. After solid-liquid separation by a vibrating sieve drying unit, the liquid falls into a crystal collection box and finally ammonium salt crystal products are obtained. When the mother liquor in the mother liquor tank reaches a certain density, it is transported to the storage tank of the ammonia absorption reaction zone by a mother liquor return pump through a pipeline.

2. The method for resource recovery of ammonia-containing gas according to claim 1, characterized in that, The ammonia-containing gas mentioned in step (1) enters the gas-liquid separation pretreatment zone through the air inlet on the outer wall, and the finally purified gas enters the ammonia absorption reaction zone through the air outlet at the top along the pipeline.

3. The method for resource recovery of ammonia-containing gas according to claim 1, characterized in that, In step (2), the gas flows from bottom to top, while the absorbent flows from top to bottom. The absorbent includes sulfuric acid solution, boric acid solution, water, sodium hypochlorite and sulfuric acid mixed solution. When the liquid level in the storage tank reaches 70% of its volume, the circulation pump is started to transport the liquid in the storage tank to the absorbent distribution pipe above the packing layer for spraying.

4. The method for resource recovery of ammonia-containing gas according to claim 1, characterized in that, When the pH value is greater than 5 for more than 30 seconds and the liquid level is higher than 65% of the volume, the crystallization pump and the acid replenishment pump mentioned in step (3) start to send the liquid in the storage tank to the evaporation crystallization zone until the liquid level drops to 40%; when the crystallization pump is running, if the pH value fluctuates to greater than 5.8, the acid replenishment pump is started to replenish a small amount of acid; when the crystallization pump stops running, the acid replenishment pump is started to replenish the liquid level in the storage tank to 70% of the volume.

5. The method for resource recovery of ammonia-containing gas according to claim 1, characterized in that, The rotary concentration unit described in step (4) operates at a temperature range of 30-60℃; the multi-temperature zone annular crystallization surface is divided into three temperature zones along the material flow direction: the primary temperature zone connected to the conical surface, with a temperature range of 35-50℃; the secondary temperature zone in the middle, with a temperature range of 30-45℃; and the tertiary temperature zone at the outlet, with a temperature range of 25-35℃. The starting logic of the mother liquor reflux pump is as follows: when the density of the mother liquor in the mother liquor tank is greater than 1.2 g / cm³... 3 At that time, the reflux pump starts to transport the liquid in the mother liquor tank to the storage tank in the ammonia absorption reaction zone.

6. A resource recovery system for ammonia-containing gas, characterized in that, The system includes, from bottom to top, a gas-liquid separation pretreatment zone (1), an ammonia absorption reaction zone (2), and an evaporation crystallization zone (3); the gas-liquid separation pretreatment zone (1) includes an outer wall air inlet (101), a horizontally arranged spiral channel disk (102) and a gas distributor (103) at its top, a wire mesh demister (104) above it, an impurity gas absorption layer (105), and an air outlet (106) on the top side; the ammonia absorption reaction zone (2) includes a liquid storage tank (201) and an air inlet (206) located on the side wall of the liquid storage tank. 02) The air inlet is connected to the air outlet (106) of zone (1) through a pipe. The packing layer (203) above the storage tank, the circulation pump (205) for transporting the liquid in the storage tank to the absorption liquid distribution pipe (204) above the packing layer, the system also includes a pH meter (206) and a level gauge (207) for monitoring the storage tank, a crystallization pump (208) for pumping the liquid to the evaporation crystallization zone, an acid replenishment pump (209) for replenishing the storage tank, an exhaust port (210) on the top side and a return liquid inlet (211); The evaporation crystallization zone (3) includes a rotary concentration unit (301), a multi-temperature zone annular crystallization surface (302) connected to the rotary concentration unit, and a vibrating sieve drying unit (303) located below the annular crystallization surface. A mother liquor tank (304) and a crystal collection box (305) are provided below the vibrating sieve drying unit (303). The mother liquor tank (304) is connected to a mother liquor circulation pump (306) and a mother liquor return pump (307) through pipes. The mother liquor circulation pump (306) is used to pump the mother liquor back into the rotary concentration unit (301). The mother liquor return pump (307) is used to pump the mother liquor in the mother liquor tank (304) back to the storage tank (201) of the ammonia absorption reaction zone (2). A densitometer (308) is provided in the mother liquor tank (304), and there is an inlet (309) on the side wall, which is connected to the crystallization pump (208) through a pipe. The steam outlet (310) is located at the top of the zone (3).

7. The resource recovery system for ammonia-containing gas according to claim 6, characterized in that, The bottom of the spiral channel disk in the gas-liquid separation pretreatment zone (1) is an upwardly convex curved surface. The impurity gas absorption layer (105) is filled with, but is not limited to, activated carbon, supported metal oxides, zeolite molecular sieves, and ceramic filter membranes. A gas distributor is installed in the center of its top sealing cap.

8. The resource recovery system for ammonia-containing gas according to claim 6, characterized in that, The packing material in the ammonia absorption reaction zone (2) includes, but is not limited to, Raschig rings, Pall rings, step rings, arc saddle packing, rectangular saddle packing, ring rectangular saddle, and spherical packing.

9. The resource recovery system for ammonia-containing gas according to claim 6, characterized in that, The rotary concentration unit (301) of the evaporation crystallization zone (3) is a conical surface with dotted protrusions. The surface of its multi-temperature zone annular crystallization surface (302) is provided with square grooves. The grooves are 2 mm deep and 2.4-3 mm wide. The annular crystallization surface is inclined at an angle of 3-5°. The vibrating sieve drying unit (303) is equipped with a horizontal reciprocating vibration mechanism and a fan.

10. The resource recovery system for ammonia-containing gas according to claim 6, characterized in that, The system is also equipped with a cleaning system, which is connected in parallel with the circulation pump (306) via an external hot water pump and pipes, and is used to rinse the equipment surface in the evaporation crystallization zone (3).

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