A device for purifying ammonia tail gas to produce ultra-pure ammonia

Abstract

The utility model discloses a kind of device for purifying ammonia-containing tail gas to prepare ultra-pure ammonia, comprising: ammonia water section device, industrial ammonia section device and 7N ultra-pure ammonia section device;Ammonia water section device is converted into 3%-22% ammonia water solution by two-stage ammonia absorption tower and buffer tank system, with ammonia tail gas;Industrial ammonia section device adopts ammonia distillation tower and condensing system, to realize the preparation of industrial grade ammonia;7N ultra-pure ammonia section device is cooperated with precision filtration device through the synergistic effect of light removal tower and heavy removal tower, and finally output 7N grade ultra-pure ammonia with purity ≥99.99999%。The utility model adopts heat coupling technology, and the waste heat of ammonia distillation tower wastewater is used for raw material preheating, which significantly reduces energy consumption;The utility model has the advantages of high ammonia recovery rate, high product purity (metal impurities <1 ppb), low energy consumption and green environmental protection, and can be widely applied in high-end manufacturing fields such as semiconductor, photovoltaic, LED, etc., to realize the high-value utilization of ammonia-containing tail gas.

Description

Technical Field

[0001] This utility model relates to the technical field of gas purification devices, specifically to a device for purifying ammonia-containing tail gas to produce ultrapure ammonia. Background Technology

[0002] With the rapid development of high-end manufacturing industries such as semiconductors, LEDs, and photovoltaics, ultra-high purity ammonia (≥7N, i.e., purity ≥99.99999%) is widely used as a key electronic specialty gas in processes such as epitaxial growth and silicon nitride deposition. However, traditional ultra-pure ammonia production mainly relies on high-purity liquid ammonia distillation, which suffers from high energy consumption, strong dependence on raw materials, and expensive purification costs. Meanwhile, ammonia-containing tail gases emitted by industries such as chemicals, electronics, and metallurgy (such as synthetic ammonia off-gas and semiconductor etching waste gas) are typically treated only through simple absorption to recover low-value-added ammonia water or industrial-grade ammonia (99%–99.9%), failing to achieve high-value utilization and resulting in resource waste and environmental pressure.

[0003] Currently, industrial treatment of ammonia-containing tail gas mainly includes absorption, adsorption, membrane separation, and distillation, but each has its limitations. Ammonia water absorption involves absorbing ammonia-containing tail gas through water spraying to form 10%–20% ammonia water, which is usually used directly as industrial raw material or wastewater. While simple, this method results in low added value and cannot be further purified to high-purity ammonia. Furthermore, the absorption process easily carries impurities such as CO2 and H2S, affecting subsequent refining. Industrial ammonia distillation involves some companies using ammonia stripping towers to distill ammonia water, obtaining approximately 99.9% industrial ammonia. However, this process typically uses conventional packed or plate towers, resulting in low separation efficiency and high energy consumption (large steam consumption). It is also difficult to effectively remove light components (H2, N2, CO, etc.) and heavy metal impurities (Fe, Ni, etc.), failing to meet the purity requirements for electronic-grade ammonia. The traditional ultrapure ammonia production process mainly relies on high-purity liquid ammonia (5N-6N) as raw material, which is further purified to 7N through low-temperature adsorption and precision distillation. However, this technology requires high purity of raw ammonia, relies on imports, and is expensive. During the distillation process, it is necessary to strictly control trace amounts of water, oxygen (≤0.1ppm) and metal impurities (≤0.1ppb), which is technically challenging. The existing light removal tower (removing H2, N2, etc.) and heavy removal tower (removing metal impurities) have low coupling efficiency, and the product yield is usually less than 70%.

[0004] Therefore, in response to the above problems, this utility model proposes an apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia, which sequentially converts the ammonia-containing tail gas into ammonia water → industrial ammonia → 7N ultrapure ammonia, thereby improving the purity and recovery rate of ammonia. Utility Model Content

[0005] The purpose of this utility model is to provide an apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia, so as to realize the recovery and purification of ultrapure ammonia.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] An apparatus for purifying ammonia tail gas to produce ultrapure ammonia includes: an ammonia water section apparatus, an industrial ammonia section apparatus, and a 7N ultrapure ammonia section apparatus; the ammonia water section apparatus includes: a blower (31), a buffer tank I (6), a buffer tank II (7), a heat exchanger (8), an ammonia water tank (9), a primary ammonia absorption tower (1), an ammonia water pump I (34), an ammonia water storage tank (12), a secondary ammonia absorption tower (2), a dilute ammonia water tank (10), an ammonia water pump II (35), a water tank (11), an ammonia water pump III (36), and an ammonia water filling pump (38);

[0008] The industrial ammonia section equipment includes: an ammonia water feed pump (32), an ammonia water filter (17), a preheater (21), an ammonia stripping tower (3), an ammonia stripping tower condenser (22), an ammonia stripping tower reboiler (27), a receiving tank (14), a reflux pump (30), an industrial ammonia buffer tank (13), a liquid ammonia feed pump (33), and a liquid ammonia filter (18);

[0009] The 7N ultrapure ammonia section includes: a light-removal tower (4), a light-removal tower condenser (23), a light-removal tower reboiler (28), a light-removal tower reflux tank (15), a heavy-removal tower (5), a heavy-removal tower condenser (24), a heavy-removal tower reboiler (29), a heavy-removal tower reflux tank (16), a residual liquid vaporizer (37), a product cooler (25), a finished product filter (19), a finished product tank (20), and a booster vaporizer (26).

[0010] Furthermore, the input end of the heat exchanger (8) is connected to the top gas phase outlet of buffer tank I (6) and buffer tank II (7), and the output end of the heat exchanger (8) is connected to the ammonia tank (9); the top gas phase outlet of the ammonia tank (9) is connected to the first-stage ammonia absorption tower (1), and the bottom liquid phase outlet of the ammonia tank (9) is connected to the ammonia storage tank (12) through the ammonia pump I (34).

[0011] Furthermore, the vapor phase outlet at the top of the ammonia stripping tower (3) is connected to the ammonia stripping tower condenser (22), the vapor phase outlet of the ammonia stripping tower condenser (22) is connected to the buffer tank II (7), and the liquid phase outlet is connected to the receiving tank (14); the receiving tank (14) is connected to the top of the ammonia stripping tower (3) via a reflux pump (30), and the liquid phase outlet at the bottom of the receiving tank (14) is connected to the industrial ammonia buffer tank (13) on one side and to the light-duty removal tower (4) on the other side.

[0012] Furthermore, the gas phase outlet at the top of the light-removing tower (4) is connected to the light-removing tower condenser (23), the gas phase outlet of the light-removing tower condenser (23) is connected to the buffer tank II (7), and the liquid phase outlet of the light-removing tower condenser (23) is connected to the light-removing tower reflux tank (15); the light-removing tower reflux tank (15) is connected to the top of the light-removing tower (4) via a gravity flow pipe, and the liquid phase outlet at the bottom of the light-removing tower (4) is connected to the heavy-removing tower (5) via a pressure differential.

[0013] Furthermore, the gas phase outlet at the top of the deweight removal tower (5) is connected to the deweight removal tower condenser (24), the gas phase outlet of the deweight removal tower condenser (24) is connected to the buffer tank II (7), and the liquid phase outlet of the deweight removal tower condenser (24) is connected to the deweight removal tower reflux tank (16); the deweight removal tower reflux tank (16) is connected to the top of the deweight removal tower (5) through a gravity flow pipe; the upper side of the deweight removal tower (5) is provided with an ultrapure ammonia collection outlet, which is connected to the product cooler (25).

[0014] Furthermore, the top gas phase outlet of the finished product tank (20) is connected to the client, and the bottom liquid phase outlet is connected to the filling system; the finished product tank (20) is also connected to a booster vaporizer (26), the gas phase outlet of the booster vaporizer (26) is connected to the top of the finished product tank (20), and the liquid phase outlet is connected to the bottom of the finished product tank (20).

[0015] Furthermore, the ammonia stripping tower reboiler (27) is heated by heat transfer oil with a heat source temperature of 250-300℃; the light-light-removal tower reboiler (28) and the heavy-removal tower reboiler (29) are heated by hot water at 50-90℃.

[0016] Furthermore, the ammonia filter (17) has a pore size of 1 to 10 micrometers, the liquid ammonia filter (18) has a pore size of 1 to 10 micrometers, and the finished product filter (19) has a pore size of 0.001 to 0.01 micrometers.

[0017] Furthermore, the operating pressure of the light removal tower (4) is 1.85 to 1.95 MPa, and the operating pressure of the heavy removal tower (5) is 1.65 to 1.75 MPa.

[0018] Furthermore, the bottom of the ammonia stripping tower (3) is provided with a heavy component impurity discharge port with a discharge temperature of 35-50°C. The heavy component impurity is wastewater with an ammonia content of less than 20 ppm, which serves as the heat source for the preheater (21).

[0019] Furthermore, the gas phase that is purified by this utility model device and finally sent to the client is controlled by a pressure booster vaporizer to deliver to the client at a pressure of about 100 PSI; the gas phase pipeline delivered to the client is kept at a temperature of 35-40°C by a high-temperature heat tracing cable; the heat tracing cable is used to prevent the product from liquefying and affecting the client's use.

[0020] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:

[0021] 1. This utility model achieves efficient utilization of resources and realizes the cascade utilization of ammonia-containing tail gas, converting low-value-added tail gas into high-value-added 7N-grade ultrapure ammonia products. The ammonia recovery rate is as high as 99% or more, which is far higher than the recovery rate of about 70% of the traditional process. Through the buffer tank system and multi-stage reflux design, the unreacted gas is recycled.

[0022] 2. This utility model product has high purity. It adopts a dual-tower distillation process (light component removal tower + heavy component removal tower), which can effectively remove light components (H2, N2, etc.) and heavy components (metal impurities). It is equipped with a 0.001~0.01μm precision filter to ensure that the metal impurity content in the product is <1ppb. The final product purity reaches 7N grade (≥99.99999%), which meets the stringent requirements of the semiconductor industry.

[0023] 3. This utility model is energy-saving and environmentally friendly. It uses the waste heat from the ammonia stripping tower to preheat the raw materials, reducing energy consumption by more than 30%. It uses hot water at 50-90℃ as the heat source for the reboiler, which saves 40% energy compared to traditional steam heating. The entire system achieves closed-loop operation with no wastewater or exhaust gas discharge, resulting in excellent environmental performance. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of this utility model. For those skilled in the art, other drawings can be made based on these drawings without creative effort.

[0025] Figure 1 This is a process flow diagram of Embodiment 1 of this utility model;

[0026] Among them, 1- Primary ammonia absorption tower; 2- Secondary ammonia absorption tower; 3- Ammonia stripping tower; 4- Light ammonia removal tower; 5- Heavy ammonia removal tower; 6- Buffer tank I; 7- Buffer tank II; 8- Heat exchanger; 9- Ammonia water tank; 10- Dilute ammonia water tank; 11- Water tank; 12- Ammonia water storage tank; 13- Industrial ammonia buffer tank; 14- Receiving tank; 15- Light ammonia removal tower reflux tank; 16- Heavy ammonia removal tower reflux tank; 17- Ammonia water filter; 18- Liquid ammonia filter; 19- Finished product filter; 20- Finished product tank; 2 1-Preheater; 22-Ammonia stripping tower condenser; 23-Light precipitator removal tower condenser; 24-Heavy precipitator removal tower condenser; 25-Product cooler; 26-Pressure booster vaporizer; 27-Ammonia stripping tower reboiler; 28-Light precipitator removal tower reboiler; 29-Heavy precipitator removal tower reboiler; 30-Reflux pump; 31-Blower; 32-Ammonia water feed pump; 33-Liquid ammonia feed pump; 34-Ammonia water pump I; 35-Ammonia water pump II; 36-Ammonia water pump III; 37-Residual liquid vaporizer; 38-Ammonia water filling pump. Detailed Implementation

[0027] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present utility model in a schematic manner. Therefore, they only show the components related to the present utility model. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0029] Example 1

[0030] See appendix Figure 1 This embodiment provides an apparatus for purifying ammonia tail gas to produce ultrapure ammonia, including: an ammonia water section apparatus, an industrial ammonia section apparatus, and a 7N ultrapure ammonia section apparatus; the ammonia water section apparatus includes: a blower (31), a buffer tank I (6), a buffer tank II (7), a heat exchanger (8), an ammonia water tank (9), a primary ammonia absorption tower (1), an ammonia water pump I (34), an ammonia water storage tank (12), a secondary ammonia absorption tower (2), a dilute ammonia water tank (10), an ammonia water pump II (35), a water tank (11), an ammonia water pump III (36), and an ammonia water filling pump (38);

[0031] The industrial ammonia section equipment includes: an ammonia water feed pump (32), an ammonia water filter (17), a preheater (21), an ammonia stripping tower (3), an ammonia stripping tower condenser (22), an ammonia stripping tower reboiler (27), a receiving tank (14), a reflux pump (30), an industrial ammonia buffer tank (13), a liquid ammonia feed pump (33), and a liquid ammonia filter (18);

[0032] The 7N ultrapure ammonia section includes: a light-removal tower (4), a light-removal tower condenser (23), a light-removal tower reboiler (28), a light-removal tower reflux tank (15), a heavy-removal tower (5), a heavy-removal tower condenser (24), a heavy-removal tower reboiler (29), a heavy-removal tower reflux tank (16), a residual liquid vaporizer (37), a product cooler (25), a finished product filter (19), a finished product tank (20), and a booster vaporizer (26);

[0033] Furthermore, the input end of the heat exchanger (8) is connected to the top gas phase outlet of buffer tank I (6) and buffer tank II (7), and the output end of the heat exchanger (8) is connected to the ammonia tank (9); the top gas phase outlet of the ammonia tank (9) is connected to the first-stage ammonia absorption tower (1), and the bottom liquid phase outlet of the ammonia tank (9) is connected to the ammonia storage tank (12) through the ammonia pump I (34);

[0034] Furthermore, the vapor phase outlet at the top of the ammonia stripping tower (3) is connected to the ammonia stripping tower condenser (22), the vapor phase outlet of the ammonia stripping tower condenser (22) is connected to the buffer tank II (7), and the liquid phase outlet is connected to the receiving tank (14); the receiving tank (14) is connected to the top of the ammonia stripping tower (3) via a reflux pump (30), and the liquid phase outlet at the bottom of the receiving tank (14) is connected in one way to the industrial ammonia buffer tank (13) and in the other way to the light-duty removal tower (4);

[0035] Furthermore, the gas phase outlet at the top of the light-weight removal tower (4) is connected to the light-weight removal tower condenser (23), the gas phase outlet of the light-weight removal tower condenser (23) is connected to the buffer tank II (7), and the liquid phase outlet of the light-weight removal tower condenser (23) is connected to the light-weight removal tower reflux tank (15); the light-weight removal tower reflux tank (15) is connected to the top of the light-weight removal tower (4) via a gravity flow pipe, and the liquid phase outlet at the bottom of the light-weight removal tower (4) is connected to the heavy-weight removal tower (5) via a pressure differential;

[0036] Furthermore, the gas phase outlet at the top of the deweight removal tower (5) is connected to the deweight removal tower condenser (24), the gas phase outlet of the deweight removal tower condenser (24) is connected to the buffer tank II (7), and the liquid phase outlet of the deweight removal tower condenser (24) is connected to the deweight removal tower reflux tank (16); the deweight removal tower reflux tank (16) is connected to the top of the deweight removal tower (5) through a gravity flow pipe; the upper side of the deweight removal tower (5) is provided with an ultrapure ammonia collection outlet, which is connected to the product cooler (25);

[0037] Furthermore, the top gas phase outlet of the finished product tank (20) is connected to the client, and the bottom liquid phase outlet is connected to the filling system; the finished product tank (20) is also connected to a booster vaporizer (26), the gas phase outlet of the booster vaporizer (26) is connected to the top of the finished product tank (20), and the liquid phase outlet is connected to the bottom of the finished product tank (20);

[0038] Furthermore, the ammonia stripping tower reboiler (27) is heated by heat transfer oil with a heat source temperature of 250-300℃; the light-weight removal tower reboiler (28) and the heavy-weight removal tower reboiler (29) are heated by hot water at 50-90℃.

[0039] Furthermore, the ammonia filter (17) has a pore size of 1 to 10 micrometers, the liquid ammonia filter (18) has a pore size of 1 to 10 micrometers, and the finished product filter (19) has a pore size of 0.001 to 0.01 micrometers;

[0040] Furthermore, the operating pressure of the light-weight removal tower (4) is 1.85–1.95 MPa, and the operating pressure of the heavy-weight removal tower (5) is 1.65–1.75 MPa;

[0041] Furthermore, the bottom of the ammonia stripping tower (3) is provided with a heavy component impurity discharge port with a discharge temperature of 35-50°C. The heavy component impurity is wastewater with an ammonia content of less than 20 ppm, which serves as the heat source for the preheater (21).

[0042] Specifically, in the ammonia section: the low-pressure ammonia-containing tail gas from the client is pressurized by a blower (31) and combined with the high-pressure ammonia-containing tail gas from the client before being sent to buffer tank I (6). The tail gas emitted under subsequent operating conditions is sent to buffer tank II (7). The top gas phase outlets of buffer tank I and buffer tank II are connected to the ammonia absorption device. The raw materials from buffer tank I and buffer tank II are sent to the heat exchanger (8) in the ammonia absorption device through the top gas phase outlet, and then sent to the ammonia tank (9) through the heat exchanger. The gas phase part enters the first-stage ammonia absorption tower (1) through the top gas phase outlet of the ammonia tank, and the liquid phase part is sent to the ammonia storage tank through ammonia pump I (34). 12); The gas phase separated by the first-stage ammonia absorption tower enters the second-stage ammonia absorption tower (2) through the top outlet of the tower, and the liquid phase enters the dilute ammonia water tank (10). The liquid phase in the dilute ammonia water tank is then sent to the ammonia water tank by ammonia water pump II (35). The gas phase separated by the second-stage ammonia absorption tower meets the emission standards and is discharged. The liquid phase enters the water tank (11). The liquid phase in the water tank is then sent to the dilute ammonia water tank by ammonia water pump III (36). Finally, the liquid phase entering the ammonia water storage tank from the ammonia water tank is ammonia water with a concentration of 18%. A portion of the ammonia water in the ammonia water storage tank is used as raw material for subsequent industrial ammonia, and a portion can be sold externally through the ammonia water filling pump (38).

[0043] Industrial ammonia section: Ammonia water from the ammonia water storage tank is pressurized to 2.0 MPa by the ammonia water feed pump (32), and then sent to the preheater (21) through the ammonia water filter (17). After being preheated to 130°C by the preheater, it enters the middle of the ammonia stripping tower (3). The gas phase of the material in the ammonia stripping tower is condensed by the ammonia stripping tower condenser (22) at the top of the tower and then sent to the receiving tank (14). The gas phase light component impurities of the ammonia stripping tower condenser are discharged to the buffer tank II. A portion of the liquid phase in the receiving tank is returned to the top of the tower by the reflux pump (30). A portion is stored as industrial ammonia product in the industrial ammonia buffer tank (13). A portion can be directly transported to the light component removal tower as raw material for the light component removal tower. The liquid phase in the industrial ammonia buffer tank is sent to the light component removal tower through the liquid ammonia feed pump (33) and the liquid ammonia filter (18). The purity of the obtained industrial ammonia is ≥99.8%.

[0044] 7N Ultrapure Ammonia Section: Industrial liquid ammonia from the industrial ammonia section is pressurized to 2.0 MPa by the liquid ammonia feed pump and fed into the light component removal tower (4). After pressurization and separation, the light components accumulate at the top of the light component removal tower. The gas phase at the top of the light component removal tower is condensed by the light component removal tower condenser (23). The condensed non-condensable gas is taken out as the top of the tower and sent to the buffer tank II. The condensed liquid phase enters the light component removal tower reflux tank (15) and returns to the top of the light component removal tower by gravity. The bottom of the tower is taken out containing heavy components. Liquid ammonia enters the de-heavy metal removal tower (5) through pressure difference. After pressurization and separation, water, oil, and heavy metal ions are removed. The gas phase at the top of the tower is condensed by the de-heavy metal removal tower condenser (24). After condensation, the liquid phase flows into the de-heavy metal removal tower reflux tank (16) and flows back into the de-heavy metal removal tower by gravity. Qualified ultrapure ammonia products are collected from the upper side of the de-heavy metal removal tower. Liquid ammonia containing water, oil, and heavy metals in the bottom of the de-heavy metal removal tower is vaporized into a gas phase by the residual liquid vaporizer (37) and then enters the buffer tank II.

[0045] The qualified ultrapure ammonia product extracted from the upper side of the de-weighting tower is first cooled by the product cooler (25) and then filtered by the finished product filter (19) before entering the finished product tank (20) for storage. The gaseous finished product in the finished product tank is sent to the client for use through the top outlet. The finished product tank is equipped with a booster vaporizer (26). The gaseous phase of the booster vaporizer enters the finished product tank through the top outlet to pressurize the finished product tank. The liquid phase at the bottom of the booster vaporizer is connected to the bottom of the finished product tank. The liquid phase at the bottom of the finished product tank is connected to the finished product filling system, which can realize the filling of ISO tank trucks, T / Y steel cylinders and 40L steel cylinders.

[0046] In summary, this invention achieves efficient resource utilization, realizing the cascade utilization of ammonia-containing tail gas and converting low-value-added tail gas into high-value-added 7N-grade ultrapure ammonia product. The ammonia recovery rate is over 99%, far exceeding the recovery rate of around 70% of traditional processes. Through a buffer tank system and multi-stage reflux design, unreacted gases are recycled. The product of this invention boasts high purity, employing a dual-tower distillation process (light component removal tower + heavy component removal tower) to effectively remove light components (H2, N2, etc.) and heavy components (metallic impurities). Equipped with a 0.001-0.01μm precision filter, this product ensures that the content of metal impurities is <1ppb, and the final product purity reaches 7N grade (≥99.99999%), meeting the stringent requirements of the semiconductor industry. This utility model is energy-saving and environmentally friendly, utilizing the waste heat from the ammonia stripping tower to preheat the raw materials, reducing energy consumption by more than 30%. It uses 50-90℃ hot water as the heat source for the reboiler, saving 40% energy compared to traditional steam heating. The entire system achieves closed-loop operation with no wastewater or exhaust gas discharge, demonstrating excellent environmental performance.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to the above embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia, characterized in that, include: Ammonia water section unit, industrial ammonia section unit, and 7N ultrapure ammonia section unit; The ammonia water section equipment includes: a blower (31), a buffer tank I (6), a buffer tank II (7), a heat exchanger (8), an ammonia water tank (9), a primary ammonia absorption tower (1), an ammonia water pump I (34), an ammonia water storage tank (12), a secondary ammonia absorption tower (2), a dilute ammonia water tank (10), an ammonia water pump II (35), a water tank (11), an ammonia water pump III (36), and an ammonia water filling pump (38); The industrial ammonia section includes: an ammonia feed pump (32), an ammonia filter (17), a preheater (21), an ammonia stripping tower (3), an ammonia stripping tower condenser (22), an ammonia stripping tower reboiler (27), a receiving tank (14), a reflux pump (30), an industrial ammonia buffer tank (13), a liquid ammonia feed pump (33), and a liquid ammonia filter (18). The 7N ultrapure ammonia section includes: a light-weight removal tower (4), a light-weight removal tower condenser (23), a light-weight removal tower reboiler (28), a light-weight removal tower reflux tank (15), a heavy-weight removal tower (5), a heavy-weight removal tower condenser (24), a heavy-weight removal tower reboiler (29), a heavy-weight removal tower reflux tank (16), a residual liquid vaporizer (37), a product cooler (25), a finished product filter (19), a finished product tank (20), and a booster vaporizer (26). The input end of the heat exchanger (8) is connected to the top gas phase outlet of buffer tank I (6) and buffer tank II (7), and the output end of the heat exchanger (8) is connected to the ammonia tank (9); the top gas phase outlet of the ammonia tank (9) is connected to the first-stage ammonia absorption tower (1), and the bottom liquid phase outlet of the ammonia tank (9) is connected to the ammonia storage tank (12) through ammonia pump I (34). The vapor outlet at the top of the ammonia stripping tower (3) is connected to the ammonia stripping tower condenser (22). The vapor outlet of the ammonia stripping tower condenser (22) is connected to the buffer tank II (7), and the liquid outlet is connected to the receiving tank (14). The receiving tank (14) is connected to the top of the ammonia stripping tower (3) via a reflux pump (30). One liquid outlet at the bottom of the receiving tank (14) is connected to the industrial ammonia buffer tank (13), and the other is connected to the light-duty removal tower (4). The gas phase outlet at the top of the light-light removal tower (4) is connected to the light-light removal tower condenser (23), the gas phase outlet of the light-light removal tower condenser (23) is connected to the buffer tank II (7), and the liquid phase outlet of the light-light removal tower condenser (23) is connected to the light-light removal tower reflux tank (15). The light-light removal tower reflux tank (15) is connected to the top of the light-light removal tower (4) via a gravity flow pipe, and the liquid phase outlet at the bottom of the light-light removal tower (4) is connected to the heavy-weight removal tower (5) via a pressure differential. The top gas phase outlet of the de-weighting tower (5) is connected to the de-weighting tower condenser (24), the gas phase outlet of the de-weighting tower condenser (24) is connected to the buffer tank II (7), and the liquid phase outlet of the de-weighting tower condenser (24) is connected to the de-weighting tower reflux tank (16); the de-weighting tower reflux tank (16) is connected to the top of the de-weighting tower (5) through a gravity flow pipe; the upper side of the de-weighting tower (5) is provided with an ultrapure ammonia collection outlet, which is connected to the product cooler (25). The top gas phase outlet of the finished product tank (20) is connected to the client, and the bottom liquid phase outlet is connected to the filling system; the finished product tank (20) is also connected to a booster vaporizer (26), the gas phase outlet of the booster vaporizer (26) is connected to the top of the finished product tank (20), and the liquid phase outlet is connected to the bottom of the finished product tank (20).

2. The apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia as described in claim 1, characterized in that, The ammonia stripping tower reboiler (27) is heated by heat transfer oil with a heat source temperature of 250~300℃; the light-weight removal tower reboiler (28) and the heavy-weight removal tower reboiler (29) are heated by hot water at 50~90℃.

3. The apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia as described in claim 1, characterized in that, The ammonia water filter (17) has a pore size of 1~10 micrometers, the liquid ammonia filter (18) has a pore size of 1~10 micrometers, and the finished filter (19) has a pore size of 0.001~0.01 micrometers.

4. The apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia as described in claim 1, characterized in that, The operating pressure of the light removal tower (4) is 1.85~1.95MPa, and the operating pressure of the heavy removal tower (5) is 1.65~1.75MPa.

5. The apparatus for purifying ammonia-containing tail gas to produce ultrapure ammonia as described in claim 1, characterized in that, The bottom of the ammonia stripping tower (3) is equipped with a heavy component impurity discharge port with a discharge temperature of 35~50℃. The heavy component impurity is wastewater with an ammonia content of less than 20ppm, which serves as the heat source for the preheater (21).

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