A system for recovering nicotinic acid tail vapor

Abstract

The utility model provides a kind of nicotinic acid tail gas recovery system, including the flue gas absorption tank, ammonium sulfate crystallization tank and ammonium sulfate dryer that are sequentially communicated along process flow, the flue gas absorption tank uses upper and lower layered structure, flue gas absorption tank lower layer is provided with first spray head and is connected with first tail gas inlet pipe, first tail gas inlet pipe is equipped with delivery fan, the second tail gas inlet pipe of the breathing valve of upper layer intercommunication is provided;Flue gas absorption tank top is provided with second spray head and is connected with desalted water inlet pipe, side is provided with ammonia water inlet pipe for introducing neutralization medium, the installation position of the first spray head is immersed in tank liquid level below, to ensure sufficient gas-liquid contact and absorption efficiency.The utility model has the beneficial effect that: it realizes the fundamental change from "waste treatment" to "resource recovery".System through the unique double-layer design of flue gas absorption tank, main tail gas stream from production line and breathing tail gas when device start-up and shutdown or fluctuation can be simultaneously and efficiently handled, and the flexibility and reliability of processing capacity are improved.

Description

Technical Field

[0001] This utility model relates to the field of chemical equipment, specifically to a nicotine tail gas recovery system. Background Technology

[0002] In chemical production, nicotinic acid is used extensively as a key organic synthesis intermediate and inducing agent. Its industrial production typically involves complex processes such as high-temperature oxidation, and the finished nicotinic acid often contains small amounts of impurities and may be acidic. To ensure continuous and stable production, factories need to use large fixed-roof storage tanks on-site to store raw materials such as concentrated sulfuric acid required for nicotinic acid production. During storage, the pressure in the gas phase space inside the tank fluctuates frequently due to "small breathing" losses caused by diurnal temperature variations and "large breathing" losses caused by feeding and discharging. To prevent overpressure or negative pressure instability in the storage tank, a breather valve is installed on the tank top, and the discharged gas is directly led to high altitude for emission through a DN65 pipe. These continuously emitted gases are not inert air, but a volatile mixture saturated with sulfuric acid mist, constituting the nicotinic acid tail gas that needs to be treated.

[0003] Direct emission of SO3-rich nicotine exhaust gas poses multiple serious hazards. First, from an economic perspective, SO3 is a key component in sulfuric acid production; direct emission means a continuous waste of valuable sulfur resources, essentially discarding valuable raw materials as waste gas, increasing material costs. Second, environmentally, these highly acidic gases, once released into the atmosphere, quickly combine with moisture to form sulfuric acid mist, which, after settling, pollutes surrounding soil and water bodies, alters pH levels, and damages the ecological environment. The most direct and severe hazard is to the health and safety of on-site personnel: even after dilution, the emitted SO3 and sulfuric acid mist are extremely irritating and corrosive. If employees accidentally inhale these acidic substances, they can severely damage the respiratory tract and nasal mucosa, leading to inflammation, bleeding, and even more serious chronic health problems, seriously violating occupational health and safety standards and impacting the physical and mental health of employees and the stable operation of the enterprise.

[0004] Therefore, effective treatment of nicotine exhaust gas is both necessary and urgent. On the one hand, increasingly stringent environmental regulations impose clear limits and penalties on acid gas emissions; unchecked emissions will expose companies to significant compliance risks and administrative penalties. On the other hand, in the context of fierce industry competition, cost reduction and efficiency improvement are the lifeline of enterprises. Recovering and reusing SO3 from exhaust gas not only completely eliminates environmental pollution and health threats but also turns waste into treasure, directly reducing the amount of external sulfuric acid procurement, lowering production costs, and improving resource utilization efficiency—a necessary requirement for achieving green, safe, and sustainable development. Utility Model Content

[0005] To overcome the above shortcomings and solve the problem of difficult recovery of nicotine exhaust gas.

[0006] This utility model provides a nicotinic acid tail gas recovery system, including a flue gas absorption tank, an ammonium sulfate crystallization tank and an ammonium sulfate dryer connected sequentially along the process flow. The flue gas absorption tank adopts an upper and lower layer structure. The lower layer of the flue gas absorption tank is provided with a first nozzle connected to a first tail gas inlet pipe. The first tail gas inlet pipe is provided with a conveying fan. The upper layer is connected to a second tail gas inlet pipe provided with a breathing valve. A second nozzle is installed at the top of the flue gas absorption tank and connected to the demineralized water inlet pipe. An ammonia water inlet pipe for introducing neutralizing medium is installed on the side. The first nozzle is installed below the liquid surface in the tank to ensure sufficient gas-liquid contact and absorption efficiency.

[0007] As a preferred embodiment, a nicotinic acid tail gas buffer tank is also provided, which is connected to the second tail gas inlet pipe and the first tail gas inlet pipe respectively. The top of the nicotinic acid tail gas buffer tank is provided with a demineralized water inlet pipe, the bottom is provided with a residual liquid outlet pipe connected to the ammonium sulfate crystallization tank, and the side is connected to a nicotinic acid tail gas conveying pipe for connecting to the upstream tail gas.

[0008] As a preferred embodiment, the top of the ammonium sulfate crystallization tank is provided with a third nozzle connected to the ammonia water inlet pipe, and an ammonium sulfate inlet pipe connected to the flue gas absorption tank; the bottom of the ammonium sulfate crystallization tank is provided with an ammonium sulfate crystallization conveying pipe, which is connected to the feed port of the ammonium sulfate dryer; the outer wall of the ammonium sulfate crystallization tank is wrapped with a heating pipe for providing the heat required for crystallization, and an agitator for promoting crystal formation and suspension is installed inside.

[0009] As a preferred embodiment, the ammonium sulfate dryer is equipped with a nitrogen inlet pipe and a nitrogen outlet pipe. The nitrogen inlet pipe is equipped with a heater, and the nitrogen outlet pipe is connected to the heating pipe to realize heat energy recovery. The bottom of the ammonium sulfate dryer is also equipped with an ammonium sulfate crystallization outlet pipe for outputting the final product. This outlet pipe is connected to the finished product yard through a conveying device.

[0010] As a preferred embodiment, the ammonium sulfate crystallization outlet pipe is equipped with an ammonium sulfate crystallization buffer tank, which is used for secondary drying of ammonium sulfate crystals by nitrogen blowing.

[0011] As a preferred embodiment, the residual liquid outlet pipe is sequentially equipped with a residual liquid filter for removing solid impurities and a residual liquid transfer pump for providing transfer pressure along the flow direction.

[0012] As a preferred embodiment, the lower layer of the flue gas absorption tank is provided with a sight glass for observing the gas-liquid contact.

[0013] The beneficial effects of this utility model are as follows: 1. This utility model provides a complete, efficient, and resource-efficient solution for treating nicotine tail gas, converting pollutant-containing tail gas into valuable commercial ammonium sulfate, achieving a fundamental shift from "waste treatment" to "resource recovery." The system, through its unique double-layer design of the flue gas absorption tank, can simultaneously and efficiently treat both the main tail gas flow from the production line and the breathing tail gas during equipment start-up, shutdown, or fluctuations, enhancing the flexibility and reliability of its processing capacity. Precise replenishment of demineralized water and ammonia water within the absorption tank ensures a thorough reaction with the acidic tail gas to generate an ammonium sulfate solution. The design of the first nozzle submerged below the liquid surface significantly enhances gas-liquid contact efficiency, ensuring highly efficient absorption of pollutants.

[0014] 2. This invention utilizes the synergistic effect of external heating and internal stirring to create a supersaturated environment that promotes crystal precipitation, ensuring the final product's yield and quality. The subsequent ammonium sulfate dryer employs a closed-loop circulating heated nitrogen gas as the drying medium to dry the precipitated crystals into a high-purity solid product. Simultaneously, the waste heat from the moisture-rich nitrogen gas is used to insulate the pre-crystallization tank, significantly reducing the overall system energy consumption. This system not only completely eliminates pollutant emissions from the exhaust gas, meeting stringent environmental protection requirements, but also transforms pollutants into directly marketable ammonium sulfate fertilizer, turning waste into treasure and creating significant economic benefits. Furthermore, the entire system features low energy consumption, stable operation, and a high degree of automation, exhibiting excellent comprehensive performance. Attached Figure Description

[0015] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a schematic diagram of the structure of the present invention.

[0016] The numbers in the attached diagram are: 1. Flue gas absorption tank; 11. First nozzle; 12. First tail gas inlet pipe; 13. Second tail gas inlet pipe; 14. Second nozzle; 15. Demineralized water inlet pipe; 16. Conveying fan; 17. Ammonia water inlet pipe; 2. Ammonium sulfate crystallization tank; 21. Third nozzle; 22. Heating pipe; 23. Agitator; 3. Ammonium sulfate dryer; 31. Nitrogen inlet pipe; 32. Nitrogen outlet pipe; 33. Ammonium sulfate crystallization outlet pipe; 4. Nicotinic acid tail gas buffer tank; 41. Residual liquid outlet pipe; 42. Nicotinic acid tail gas conveying pipe; 43. Residual liquid filter; 44. Residual liquid conveying pump; 5. Heater; 6. Ammonium sulfate crystallization buffer tank. Detailed Implementation

[0017] To illustrate the features of this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will further explain this utility model.

[0018] Example: Please see Figure 1This utility model provides a nicotinic acid tail gas recovery system, including a flue gas absorption tank 1, an ammonium sulfate crystallization tank 2, and an ammonium sulfate dryer connected sequentially along the process flow. The flue gas absorption tank 1 adopts a layered structure. The lower layer is equipped with a first nozzle 11, which is connected to a first tail gas inlet pipe 12 via a pipe. A conveying fan 16 is installed on the first tail gas inlet pipe 12. The upper layer of the flue gas absorption tank 1 is connected to a second tail gas inlet pipe 13 equipped with a breather valve via a pipe. At the top of the flue gas absorption tank 1, a second nozzle 14 is installed, which is connected to a demineralized water inlet pipe 15 via a pipe. An ammonia water inlet pipe 17 for introducing neutralization medium is provided on the side of the flue gas absorption tank 1. The installation position of the first nozzle 11 is submerged below the liquid surface in the tank to ensure sufficient gas-liquid contact and absorption efficiency. A sight glass for observing the internal gas-liquid contact is installed on the lower side wall of the flue gas absorption tank 1.

[0019] The system includes a nicotinic acid tail gas buffer tank 4. The top of this buffer tank is connected to a demineralized water inlet pipe 15 via a pipe, and its side is connected to a nicotinic acid tail gas delivery pipe 42 for receiving upstream tail gas via a pipe. The nicotinic acid tail gas buffer tank 4 is also connected to a second tail gas inlet pipe 13 and a first tail gas inlet pipe 12 via pipes. A residual liquid outlet pipe 41 is located at the bottom of the nicotinic acid tail gas buffer tank 4, which is connected to an ammonium sulfate crystallization tank 2 via a pipe. Along the flow direction, a residual liquid filter 43 for removing solid impurities and a residual liquid delivery pump 44 for providing delivery pressure are sequentially installed on the residual liquid outlet pipe 41.

[0020] A third nozzle 21 is installed at the top of the ammonium sulfate crystallization tank 2, which is connected to the ammonia water inlet pipe 17 via a pipeline. The ammonium sulfate crystallization tank 2 also has an ammonium sulfate inlet pipe connected to the bottom of the flue gas absorption tank 1 via a pipeline. An ammonium sulfate crystallization conveying pipe is installed at the bottom of the ammonium sulfate crystallization tank 2, which is connected to the feed inlet of the ammonium sulfate dryer 3. Heating pipes 22 are wound around the outer wall of the ammonium sulfate crystallization tank 2 to provide the heat required for crystallization. An agitator 23 is installed inside the tank to promote crystal formation and suspension.

[0021] The ammonium sulfate dryer 3 is equipped with a nitrogen inlet pipe 31 and a nitrogen outlet pipe 32. A heater 5 is installed on the nitrogen inlet pipe 31. The nitrogen outlet pipe 32 is connected to the heating pipe 22 wound around the outside of the ammonium sulfate crystallization tank 2 via a pipeline to achieve heat recovery. The bottom of the ammonium sulfate dryer 3 is provided with an ammonium sulfate crystallization outlet pipe 33 for outputting the final product, which is connected to the finished product yard via a conveying device. An ammonium sulfate crystallization buffer tank 6 is installed on the ammonium sulfate crystallization outlet pipe 33. The buffer tank achieves secondary drying by blowing nitrogen gas onto the ammonium sulfate crystals.

[0022] The system, through the flue gas absorption tank 1, ammonium sulfate crystallization tank 2, ammonium sulfate dryer 3 and their connecting pipes, along with components such as nicotinic acid tail gas buffer tank 4, heater 5, and ammonium sulfate crystallization buffer tank 6, realizes a complete treatment process of absorption, neutralization, crystallization, drying and heat recovery of nicotinic acid tail gas.

[0023] The above embodiments and accompanying drawings are only used to illustrate the technical solutions of this utility model and are not intended to limit this utility model. This utility model has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of this utility model do not depart from the spirit of this utility model and should also fall within the protection scope of the claims of this utility model. Other related technical structures not disclosed in detail in this utility model are existing technologies in the art.

Claims

1. A system for recovering a nicotinic acid tail vapor, the system comprising: The flue gas absorption tank (1), ammonium sulfate crystallization tank (2) and ammonium sulfate dryer (3) are connected sequentially along the process flow. The flue gas absorption tank (1) adopts an upper and lower layer structure. The lower layer of the flue gas absorption tank (1) is equipped with a first nozzle (11) connected to a first tail gas inlet pipe (12). The first tail gas inlet pipe (12) is equipped with a conveying fan (16). The upper layer is connected to a second tail gas inlet pipe (13) equipped with a breathing valve. The flue gas absorption tank (1) is equipped with a second nozzle (14) at the top, which is connected to the demineralized water inlet pipe (15). The side is equipped with an ammonia water inlet pipe (17) for introducing the neutralizing medium. The first nozzle (11) is installed below the liquid surface in the tank to ensure sufficient gas-liquid contact and absorption efficiency.

2. The niacin tail gas recovery system of claim 1, wherein: A nicotinic acid tail gas buffer tank (4) is also provided, which is connected to the second tail gas inlet pipe (13) and the first tail gas inlet pipe (12) respectively. A demineralized water inlet pipe (15) is provided at the top of the nicotinic acid tail gas buffer tank (4), a residual liquid outlet pipe (41) is provided at the bottom, which is connected to the ammonium sulfate crystallization tank (2), and the side is connected to the nicotinic acid tail gas conveying pipe (42) for connecting to the upstream tail gas.

3. The niacin tail gas recovery system of claim 1, wherein: The ammonium sulfate crystallization tank (2) is equipped with a third nozzle (21) at the top, which is connected to the ammonia water inlet pipe (17), and an ammonium sulfate inlet pipe is also provided, which is connected to the flue gas absorption tank (1); the bottom of the ammonium sulfate crystallization tank (2) is equipped with an ammonium sulfate crystallization conveying pipe, which is connected to the feed port of the ammonium sulfate dryer (3); the outer wall of the ammonium sulfate crystallization tank (2) is wrapped with a heating pipe (22) for providing the heat required for crystallization, and a stirrer (23) for promoting crystal formation and suspension is installed inside it.

4. The niacin tail gas recovery system of claim 3, wherein: The ammonium sulfate dryer (3) is equipped with a nitrogen inlet pipe (31) and a nitrogen outlet pipe (32). The nitrogen inlet pipe (31) is equipped with a heater (5), and the nitrogen outlet pipe (32) is connected to the heating pipe (22) to realize heat energy recovery. The bottom of the ammonium sulfate dryer (3) is also equipped with an ammonium sulfate crystallization outlet pipe (33) for outputting the final product. The ammonium sulfate crystallization outlet pipe (33) is connected to the finished product yard through a conveying device.

5. The niacin tail gas recovery system of claim 4, wherein: The ammonium sulfate crystallization outlet pipe (33) is equipped with an ammonium sulfate crystallization buffer tank (6), which is used for secondary drying of ammonium sulfate crystals by blowing nitrogen gas.

6. The niacin tail gas recovery system of claim 2, wherein: The residual liquid outlet pipe (41) is sequentially equipped with a residual liquid filter (43) for removing solid impurities and a residual liquid transfer pump (44) for providing transfer pressure along the flow direction.

7. The niacin tail gas recovery system of claim 1, wherein: The lower layer of the flue gas absorption tank (1) is equipped with a sight glass for observing the gas-liquid contact.

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