A device for recovering ammonia gas to produce ammonia water

Abstract

This utility model discloses a device for recovering gaseous ammonia to produce ammonia water, belonging to the field of gaseous ammonia recovery technology. The device integrates a tail gas purification section, a multi-stage absorption section, and an ammonia water collection and deep circulation section from top to bottom within its tower. It utilizes a Venturi ejector for primary high-efficiency mixing and absorption; a secondary countercurrent absorption is achieved through a packing layer and sprayers; and an innovative coil-type deep absorber is used as the tertiary absorption stage. This absorber forms a low-temperature liquid film on the cooling coil wall, achieving deep capture of trace amounts of ammonia and removal of reaction heat. In the collection section, a concentration monitor in the collection tank and an automatic control valve on the outlet pipe form a feedback system. When the ammonia water concentration reaches the standard, it is automatically collected as product; otherwise, it continues to circulate and concentrate. This utility model integrates three-stage absorption, cooling, and intelligent collection, offering significant advantages such as thorough absorption, high efficiency, stable product concentration, and a high degree of automation. It is suitable for various gaseous ammonia recovery applications.

Description

Technical Field

[0001] This utility model relates to the field of ammonia recovery technology, specifically a device for recovering ammonia gas to produce ammonia water. Background Technology

[0002] In numerous industrial processes involving ammonia, such as chemical, fertilizer, and refrigeration manufacturing, large quantities of ammonia-containing process waste gas are generated. Directly discharging this gaseous ammonia not only wastes valuable ammonia resources but also severely pollutes the environment and poses safety hazards. Therefore, recovering gaseous ammonia and producing economically valuable ammonia water is a crucial step in achieving resource recycling and clean production.

[0003] Currently, most ammonia recovery and ammonia water production units used in the industry are based on traditional absorption tower structures, primarily packed towers or spray towers. During operation, process water or dilute ammonia water is sprayed down from the top of the tower, where it undergoes mass transfer absorption with rising gaseous ammonia introduced from the bottom, either through contact with the packing surface or in direct contact. However, this traditional unit has revealed significant technical shortcomings in actual operation:

[0004] First, the absorption efficiency is limited and incomplete. The single absorption section and the limited gas-liquid contact time and area result in insufficient mass transfer driving force. Especially for low-concentration or fluctuating inlet conditions, residual ammonia often escapes from the exhaust gas, which not only fails to meet strict environmental emission standards but also causes ammonia loss.

[0005] Secondly, the accumulation of heat from the reaction affects the absorption efficiency. The combination of ammonia and water is a strongly exothermic process, and traditional devices lack efficient built-in heat removal mechanisms. Increased system temperature significantly reduces the solubility of ammonia in water, leading to a vicious cycle of decreased absorption efficiency and even affecting the stable operation of the tower.

[0006] Furthermore, the product concentration control accuracy is poor. Existing equipment mostly relies on manual experience or simple liquid level control to discharge ammonia water, which cannot monitor and control the concentration in real time. This results in large fluctuations in the concentration of the produced ammonia water, unstable quality, and affects its commercial value.

[0007] Finally, the system is limited in function and has a low degree of automation. Functions such as absorption, cooling, concentration monitoring, and product collection are usually performed by multiple decentralized devices, resulting in a long system process, large footprint, and reliance on manual operation, making it difficult to achieve efficient and continuous automated production.

[0008] Therefore, developing an integrated device that can completely absorb gaseous ammonia, effectively transfer heat, and automatically produce ammonia water of stable concentration has become an urgent technical problem to be solved in this field. Utility Model Content

[0009] This invention provides a device for recovering gaseous ammonia to produce ammonia water, aiming to solve the problems mentioned in the background art, such as incomplete absorption, the impact of reaction heat on efficiency, and inaccurate control of ammonia water product concentration in existing gaseous ammonia recovery devices.

[0010] To achieve the above objectives, this utility model provides the following technical solution: an apparatus for recovering gaseous ammonia to produce ammonia water, the apparatus comprising a tower body, an inlet pipe, a circulating pump, and an outlet pipe, wherein the tower body is provided from top to bottom with a tail gas purification section, a multi-stage absorption section, and an ammonia water collection and deep circulation section; the multi-stage absorption section includes a Venturi injector as the first stage of absorption, a packing layer and a sprayer above it as the second stage of absorption, and a coil-type deep absorber as the third stage of absorption; the ammonia water collection and deep circulation section includes a collection tank disposed below the packing layer, a concentration monitor for monitoring the liquid concentration in the collection tank, an automatic control valve connected to the outlet pipe, and the circulating pump connected to the collection tank and the Venturi injector through a pipeline.

[0011] Preferably, the coil-type deep absorber is formed by coiling a metal tube, with micropores on the coil wall, and the two ends of the coil extend to the outside of the tower body as the cooling medium inlet and cooling medium outlet, respectively.

[0012] Preferably, the concentration monitor is an online density meter or an ammonia ion concentration sensor, the automatic control valve is a solenoid valve or a pneumatic regulating valve, and the concentration monitor and the automatic control valve are connected by signal to form a concentration feedback control system.

[0013] Preferably, the liquid collection tank is connected to the inlet of the circulation pump via a circulation pipeline, and the outlet of the circulation pump is connected to the Venturi injector via one branch and to the sprayer via another branch.

[0014] Preferably, the exhaust gas purification section is a water-sealed purifier installed at the top of the tower body, and the air inlet of the water-sealed purifier is submerged below the liquid level inside it.

[0015] Preferably, the packing layer is a Pall ring packing layer or a wire mesh packing layer.

[0016] Compared with existing technologies, the device for recovering gaseous ammonia to produce ammonia water has the following advantages:

[0017] 1. This utility model achieves thorough absorption of gaseous ammonia through a three-stage synergistic effect of “Venturi mixing + packing countercurrent + coil liquid film deep absorption”, from coarse to fine and from fast to deep. This ensures that the ammonia content in the exhaust gas is far below the national environmental protection standard, thus solving the core defect of incomplete absorption in traditional devices.

[0018] 2. This utility model efficiently removes the reaction heat generated during the absorption process by setting a coil-type deep absorber, maintaining the system in the optimal low-temperature absorption environment. This not only improves the absorption efficiency but also avoids corrosion and shortened lifespan caused by excessive temperature rise.

[0019] 3. This utility model achieves precise control of ammonia concentration and automatic packaging of qualified products through an intelligent feedback system based on online concentration monitoring and automatic control valves. It fundamentally avoids problems such as large concentration fluctuations and unqualified products caused by manual intervention in traditional methods, and ensures the consistency of ammonia quality. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a device for recovering gaseous ammonia to produce ammonia water.

[0021] Figure 2 This is a schematic diagram of the internal structure of a tower in an apparatus for recovering gaseous ammonia to produce ammonia water.

[0022] In the picture:

[0023] 1. Tower body;

[0024] 2. Air intake pipe;

[0025] 3. Venturi injector;

[0026] 4. Packing layer;

[0027] 5. Sprinkler;

[0028] 6. Coil-type depth absorber; 61. Cooling medium inlet; 62. Cooling medium outlet;

[0029] 7. Circulating pump; 71. Circulating pipeline;

[0030] 8. Liquid collection tank;

[0031] 9. Concentration monitoring instrument;

[0032] 10. Discharge pipe;

[0033] 11. Automatic control valve;

[0034] 12. Water seal type purifier. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] This embodiment provides an apparatus for recovering gaseous ammonia to produce ammonia water, such as... Figures 1 to 2 As shown, the device for recovering gaseous ammonia to produce ammonia water includes a tower body 1, an inlet pipe 2, a circulation pump 7, and an outlet pipe 10. The tower body 1 is provided with a tail gas purification section, a multi-stage absorption section, and an ammonia water collection and deep circulation section from top to bottom. The multi-stage absorption section includes a Venturi injector 3 as the first stage of absorption, a packing layer 4 as the second stage of absorption and a sprayer 5 above it, and a coil-type deep absorber 6 as the third stage of absorption. The ammonia water collection and deep circulation section includes a collection tank 8 located below the packing layer 4, a concentration monitor 9 for monitoring the liquid concentration in the collection tank 8, an automatic control valve 11 connected to the outlet pipe 10, and the circulation pump 7 connected to the collection tank 8 and the Venturi injector 3 through a pipeline.

[0037] In one embodiment, the coil-type depth absorber 6 is formed by coiling a metal tube, with micropores on the coil wall, and the two ends of the coil extend to the outside of the tower body 1 as a cooling medium inlet 61 and a cooling medium outlet 62, respectively.

[0038] In this embodiment, refer to Figure 1 and Figure 2 The metal coils possess excellent thermal conductivity, facilitating cooling and heat exchange. The micropores are not intended for large-scale spraying, but rather allow small amounts of liquid to seep out or condense on the tube wall to form a uniform cryogenic liquid film. This provides a large, continuously renewing gas-liquid interface for gas passage, specifically designed to capture trace amounts of ammonia. Independent cooling medium inlets and outlets can be connected to external cooling systems, emphasizing its dual functions of "active cooling" and "surface liquid film absorption," fundamentally distinguishing it from simple spraying or packing.

[0039] In one embodiment, the concentration monitor 9 is an online density meter or an ammonia ion concentration sensor, and the automatic control valve 11 is a solenoid valve or a pneumatic regulating valve. The concentration monitor 9 and the automatic control valve 11 are connected by a signal to form a concentration feedback control system.

[0040] In this embodiment, refer to Figure 2 This indicates the specific and mature industrial devices that can achieve this function, enhancing the feasibility and specificity of the solution.

[0041] In one embodiment, the collection tank 8 is connected to the inlet of the circulation pump 7 via a circulation pipeline 71, and the outlet of the circulation pump 7 is connected to the Venturi injector 3 via a branch line and to the sprayer 5 via another branch line.

[0042] In this embodiment, refer to Figure 2 The liquid distribution path is clearly defined: one branch provides a high-pressure liquid source for the Venturi jet to ensure its spraying efficiency; the other branch provides a liquid source for the sprayer 5. This piping design allows for adjustment of the flow distribution between the two branches via valves, achieving optimizability and flexibility in system operation.

[0043] In one embodiment, the exhaust gas purification section is a water-sealed purifier 12 installed at the top of the tower body 1, and the air inlet of the water-sealed purifier 12 is submerged below the liquid level inside it.

[0044] In this embodiment, refer to Figure 2 The water seal structure provides a passive and absolutely reliable safety barrier. Even if the front-end equipment malfunctions or pressure fluctuates, the exhaust gas must be washed by liquid bubbling before it can be discharged, ensuring that the escaped ammonia gas can be effectively removed under any circumstances, meeting the most stringent environmental protection requirements.

[0045] In one embodiment, the packing layer 4 is a Pall ring packing layer or a wire mesh packing layer.

[0046] In this embodiment, refer to Figure 2 Pall rings are general-purpose high-efficiency packings with high throughput, low pressure drop, and high efficiency, suitable for most working conditions; wire mesh packings are high-efficiency packings with a huge specific surface area and extremely high separation efficiency, suitable for occasions with extremely strict requirements for absorption efficiency.

[0047] Working Principle: Process waste gas containing gaseous ammonia enters the device through inlet pipe 2, first reaching the Venturi ejector 3. Simultaneously, circulating pump 7 pressurizes ammonia water (initially dilute ammonia water or process water) from collection tank 8 and injects it at high speed into Venturi ejector 3. The Venturi effect generates a strong negative pressure at the throat, violently entraining the gaseous ammonia and mixing it instantly and efficiently with the liquid. During this process, most of the gaseous ammonia (approximately 70%-80%) is rapidly dissolved and absorbed, completing the first stage of efficient mixing and absorption. This process is also exothermic.

[0048] The gas-liquid mixture, after initial absorption, rises into the packing layer 4. Liquid from the sprayer 5 (also ammonia water supplied by the circulating pump 7) is evenly distributed onto the packing, forming a liquid film. Gas rises through the gaps in the packing, making full and continuous counter-current contact with the downstream liquid film. The large specific surface area provided by the packing allows the mass transfer process to continue, and most of the remaining ammonia gas is further absorbed, significantly increasing the ammonia concentration in this region. The absorbed liquid flows downwards into the collection tank 8, while trace amounts of ammonia gas that were not completely absorbed continue to rise.

[0049] The exhaust gas containing trace amounts of ammonia enters region 6 of the coil-type deep absorber. A cooling medium (such as cooling water) flows into the coil from the cooling medium inlet 61 and out from the cooling medium outlet 62, continuously carrying away the system's reaction heat. The low-temperature outer wall of the coil causes water vapor in the gas to condense, forming a cryogenic liquid film on the coil wall. When the exhaust gas passes over the surface of these microporous coils, the trace amounts of residual ammonia are completely dissolved and captured by this cryogenic liquid film. This step is a crucial deep purification process to ensure that the exhaust gas meets emission standards, while also addressing the system's temperature rise issue.

[0050] If absolute safety is still required after the three-stage absorption process, the gas enters the water-sealed purifier 12. The gas is forced through the liquid seal bubbling, and any trace amounts of ammonia that may escape are absorbed by the final liquid seal water. Finally, the clean gas is discharged from the top of the tower.

[0051] At the bottom of the packing layer 4, the continuously increasing concentration of ammonia water collects in the collection tank 8. The concentration monitor 9 monitors the concentration of ammonia water in the collection tank 8 in real time. Feedback control process: When the concentration is lower than the set value (e.g., 20%): the automatic control valve 11 closes, and the ammonia water in the collection tank 8 is pumped back to the system by the circulation pump 7 to continue participating in the absorption process of the Venturi and packing layer 4, realizing "circulation concentration"; when the concentration reaches or exceeds the set value: the concentration monitor 9 sends a signal, the automatic control valve 11 opens, and at this time, qualified high-concentration ammonia water is automatically transported to the finished product storage tank through the outlet pipe 10, completing the automatic collection of the product.

[0052] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. An apparatus for recovering gaseous ammonia to produce ammonia water, comprising a tower body (1), an inlet pipe (2), a circulating pump (7), and a liquid outlet pipe (10), characterized in that: The tower body (1) is provided with a tail gas purification section, a multi-stage absorption section and an ammonia water collection and deep circulation section from top to bottom; The multi-stage absorption section includes a Venturi injector (3) as the first stage of absorption, a packing layer (4) as the second stage of absorption and a sprayer (5) above it, and a coil-type depth absorber (6) as the third stage of absorption. The ammonia collection and deep circulation section includes a collection tank (8) located below the packing layer (4), a concentration monitor (9) for monitoring the liquid concentration in the collection tank (8), an automatic control valve (11) connected to the outlet pipe (10), and the circulation pump (7) connected to the collection tank (8) and the Venturi injector (3) via a pipeline.

2. The apparatus for recovering gaseous ammonia to produce ammonia water according to claim 1, characterized in that: The coil-type deep absorber (6) is formed by coiling a metal tube. The coil wall has micropores, and the two ends of the coil extend to the outside of the tower body (1) as the cooling medium inlet (61) and the cooling medium outlet (62), respectively.

3. The apparatus for recovering gaseous ammonia to produce ammonia water according to claim 1, characterized in that: The concentration monitor (9) is an online density meter or an ammonia ion concentration sensor, and the automatic control valve (11) is a solenoid valve or a pneumatic regulating valve. The concentration monitor (9) and the automatic control valve (11) are connected by signal to form a concentration feedback control system.

4. The apparatus for recovering gaseous ammonia to produce ammonia water according to claim 1, characterized in that: The collection tank (8) is connected to the inlet of the circulation pump (7) through the circulation pipeline (71), and the outlet of the circulation pump (7) is connected to the Venturi injector (3) through one branch and to the sprayer (5) through another branch.

5. The apparatus for recovering gaseous ammonia to produce ammonia water according to claim 1, characterized in that: The exhaust gas purification section is a water-sealed purifier (12) installed at the top of the tower body (1), and the air inlet of the water-sealed purifier (12) is submerged below the liquid level inside.

6. The apparatus for recovering gaseous ammonia to produce ammonia water according to claim 1, characterized in that: The packing layer (4) is a Pall ring packing layer or a wire mesh packing layer.

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