Low-temperature trapping device based on liquid nitrogen cooling

Abstract

The utility model belongs to the technical field of separation devices, and particularly relates to a low-temperature trapping device based on liquid nitrogen cooling, which comprises a kettle body, a liquid nitrogen pipeline and an air outlet are arranged at the top of the kettle body, a liquid nitrogen sprayer is arranged in the kettle body, the liquid nitrogen pipeline penetrates through the top of the kettle body and is connected with the liquid nitrogen sprayer, and an air inlet is arranged on the side wall of the kettle body. A primary stirrer, a crusher and a secondary stirrer are sequentially arranged at the lower part of the kettle body from top to bottom, a material removing assembly is arranged on the kettle body, and a material outlet is formed in the bottom of the kettle body. According to the utility model, the heat exchange efficiency is obviously improved, the separation process is simple, the problems of wall scaling and wastewater treatment are avoided, and the energy consumption and complexity of the system are reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of separation devices, and particularly relates to a cryogenic trapping device based on liquid nitrogen cooling. Background Technique

[0002] In chemical production, condensers are often used to trap gaseous materials by means of sublimation. The condensers mainly include dry condensers and wet condensers.

[0003] The dry condenser has the problem of sticky material on the inner wall during operation, and it needs to be shut down frequently for cleaning, which not only reduces production efficiency but also increases maintenance costs. In addition, its heat exchange efficiency is relatively poor, resulting in high energy consumption during the cooling process. For example, when the traditional dry device drops materials by gravity, there is still the phenomenon of solid materials adhering to the wall surface, and the trapping efficiency is low.

[0004] The wet condenser requires a large amount of spray circulating water. After the circulating water is used, it becomes wastewater, which needs to be treated additionally and will push up the operation cost. The equipment structure of the system is relatively complex. For example, at least 6 parallel independent chambers need to be configured to improve the trapping efficiency, and it is often used in combination with a multi-stage absorption tower. The complex equipment structure will increase the difficulty of operation and maintenance. Moreover, the trapped product has a high water content and needs to be further dried, which prolongs the production process and increases energy consumption.

[0005] Taking the production of isophthalonitrile as an example:

[0006] The existing isophthalonitrile trapping technology is mainly wet trapping. Its separation technology is achieved by water-cooled cooling combined with multi-stage separation. Specifically, it is as follows: High-temperature gaseous isophthalonitrile enters the spray tower after being pre-cooled by a condenser. The atomizing nozzle sprays to trap particulate matter, and then the product is recovered through processes such as pressure filtration and drying. However, this process still has the following problems:

[0007] 1. The process flow is cumbersome and the energy consumption is high: The water-cooled design relies on the series operation of multiple devices such as condensers, spray towers, pressure filters, and drying towers. Each link needs to coordinate and control parameters, resulting in a significant increase in energy consumption.

[0008] 2. Serious adhesion and scaling on the wall of the device: During the wet trapping process, sticky substances such as isophthalonitrile crystals or polymers are easily formed on the wall of the device. Especially in the traditional spray tower with an angular structure, the problem of material accumulation is more prominent. Even if it is improved to an arc transition design, it still needs to be shut down frequently for cleaning, affecting continuous production. In addition, the long-term erosion of the spray water may cause scaling on the pipe wall, further reducing the heat exchange efficiency.

[0009] 3. Equipment complexity and high maintenance cost: To avoid the problem of sticking, the equipment needs to be set up with a variety of structures. For example, multiple chambers are set up in parallel in the wet collector, such as each monomer contains 3 independent chambers to improve the heat exchange efficiency, but it increases the structural complexity and manufacturing cost; the dry collector uses a mechanical cleaning device that links a scraper, a traction rope and a dust removal box, such as scraping the inner wall once every 15-20 minutes, relying on electromagnetic suction cups, reels and other components, and the equipment failure rate is high.

[0010] 4. The additional costs of wastewater treatment and dust pollution are high: the nitrile-containing wastewater generated by the wet process needs to be treated by filtration, which increases environmental protection investment; although dry capture reduces wastewater, the material escapes to the dust removal components such as pulse dust collectors, which requires additional filtration, and also increases the operating cost.

[0011] In summary, existing technologies can alleviate the problem to a certain extent through structural remedial measures, such as multiple chambers and mechanized cleaning, but the problems of process complexity and energy consumption have not yet been solved, and there is an urgent need to simplify the design and optimize energy efficiency. Utility Model Content

[0012] In view of the above deficiencies in the prior art, the technical problem to be solved by the utility model is to provide a low-temperature capture device based on liquid nitrogen cooling, which improves the heat exchange efficiency by direct contact heat exchange between liquid nitrogen and the gas to be treated, thereby greatly simplifying the collector structure, and the separation of gasified nitrogen and solid materials is simple, thereby reducing the processing cost.

[0013] The technical solution adopted by the utility model to solve its technical problems is:

[0014] A low temperature capture device based on liquid nitrogen cooling comprises a kettle body, a liquid nitrogen pipeline and an air outlet are arranged on the top of the kettle body, a liquid nitrogen sprayer is arranged inside the kettle body, the liquid nitrogen pipeline passes through the top of the kettle body and is connected with the liquid nitrogen sprayer, an air inlet is arranged on the side wall of the kettle body, a primary agitator, a crusher and a secondary agitator are arranged in sequence from top to bottom at the lower part of the kettle body, a material removal component is arranged on the kettle body, and a material outlet is arranged at the bottom of the kettle body.

[0015] in:

[0016] The bottom of the kettle body is arranged in a funnel shape.

[0017] The liquid nitrogen sprayer is arranged in a disc shape, and the gas outlet passes through the middle of the liquid nitrogen sprayer and extends to the middle of the kettle body.

[0018] The liquid nitrogen sprayer is provided with a plurality of spray ports, which are gradually extended from one end close to the air inlet to the other end far away from the air inlet and arranged in a ladder pattern.

[0019] The outside of the kettle body is provided with a heat-insulating layer.

[0020] The described primary agitator, crusher, and secondary agitator are horizontally arranged at the lower part of the kettle body through rotating shafts respectively.

[0021] The rotating shafts of the described primary agitator, crusher, and secondary agitator all penetrate the kettle body and are connected with motors.

[0022] The described discharging assembly includes a pulse vibration discharger, a high-frequency vibration scraper, and a liftable and rotatable scraper.

[0023] The described pulse vibration discharger is arranged on the outer wall of the kettle body, the high-frequency vibration scraper is arranged on the inner wall of the kettle body, and the liftable and rotatable scraper is fixed at the top inside the kettle body.

[0024] The amplitude of the described high-frequency vibration scraper is 0.3 - 0.8 mm / s, the frequency is 10 - 15 times / min, the pulse frequency of the pulse vibration discharger is 10 - 15 times / min, the stroke of the liftable and rotatable scraper is 500 - 800 mm / s, and the rotation speed is 20 - 30 rpm.

[0025] The beneficial effects of the present utility model are as follows:

[0026] 1. The heat exchange efficiency is significantly improved.

[0027] Liquid nitrogen is in direct contact with the gas to be captured, and it quickly absorbs heat by utilizing its extremely low boiling point to achieve heat exchange. Compared with the existing wet capture method, the latent heat of vaporization of liquid nitrogen is higher, which can greatly shorten the cooling time and improve the crystallization efficiency.

[0028] 2. The separation process is simple.

[0029] The gasified nitrogen is easily separated from the solid. Nitrogen has stable properties, does not participate in chemical reactions, and has a low boiling point. The product can be recovered without the need for pressure filtration or centrifugation steps, reducing the energy consumption in the product process and increasing the product yield.

[0030] 3. The problems of fouling on the vessel wall and wastewater treatment are avoided.

[0031] Direct contact heat exchange with liquid nitrogen avoids the risk of adhesion on the vessel wall of the water cooling system and prevents crystal accumulation caused by the residual spray water. At the same time, there is no need to treat wastewater, reducing the wastewater treatment cost by about 90% and significantly improving the environmental protection performance.

[0032] 4. The system energy consumption and complexity are reduced.

[0033] Liquid nitrogen capture does not require multi-stage absorption towers and circulating water equipment, simplifying the equipment structure. In addition, the nitrogen recycling avoids the heat load of the tail gas incineration equipment in the traditional process. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of the present utility model;

[0035] Figure 2 This is a schematic structural diagram of the liquid nitrogen sprayer of the present utility model;

[0036] Figure 3 This is a schematic structural diagram of the liftable and rotatable scraper of the present utility model;

[0037] In the figure: 1. Kettle body; 2. Liquid nitrogen sprayer; 3. Primary stirrer; 4. Crusher; 5. Secondary stirrer; 6. Discharge port; 7. Gas outlet; 8. Pulse vibration material remover; 9. Heat insulation layer; 10. Spray port; 11. Air inlet; 12. Liquid nitrogen pipeline; 13. High-frequency vibration scraper; 14. Liftable and rotatable scraper. Specific embodiments

[0038] The following further describes the embodiments of the present utility model with reference to the accompanying drawings.

[0039] Embodiment 1

[0040] As Figures 1-3 shown, the low-temperature trapping device based on liquid nitrogen cooling described in the present utility model includes a kettle body 1. A liquid nitrogen pipeline 12 and a gas outlet 7 are arranged at the top of the kettle body 1. A liquid nitrogen sprayer 2 is arranged inside the kettle body 1. The liquid nitrogen pipeline 12 passes through the top of the kettle body 1 and is connected to the liquid nitrogen sprayer 2. An air inlet 11 is arranged on the side wall of the kettle body 1. A primary stirrer 3, a crusher 4, and a secondary stirrer 5 are sequentially arranged from top to bottom in the lower part of the kettle body 1. A material removing assembly is arranged on the kettle body 1. A discharge port 6 is arranged at the bottom of the kettle body 1.

[0041] The bottom of the kettle body 1 is arranged in a funnel shape.

[0042] The liquid nitrogen sprayer 2 is arranged in a disc shape. The gas outlet 7 passes through the middle of the liquid nitrogen sprayer 2 and extends to the middle of the kettle body 1. The gas outlet 7 in the middle can enable liquid nitrogen to fully contact with the gas material and then discharge nitrogen and non-condensable gas.

[0043] A plurality of spray ports 10 are arranged on the liquid nitrogen sprayer 2. The plurality of spray ports 10 are gradually extended and arranged in a stepped manner from one end close to the air inlet 11 to the end far from the air inlet 11.

[0044] A heat insulation layer 9 is arranged outside the kettle body 1.

[0045] The primary stirrer 3, the crusher 4, and the secondary stirrer 5 are horizontally arranged in the lower part of the kettle body 1 through rotating shafts respectively.

[0046] And the rotating shafts of the primary stirrer 3, the crusher 4, and the secondary stirrer 5 all penetrate the kettle body 1 and are connected with motors.

[0047] The material removing assembly includes a pulse vibration material remover 8, a high-frequency vibration scraper 13, and a liftable and rotatable scraper 14.

[0048] The pulse vibration material remover 8 is arranged on the outer wall of the kettle body 1, the high-frequency vibration scraper 13 is arranged on the inner wall of the kettle body 1, and the liftable and rotatable scraper 14 is fixed at the top inside the kettle body 1.

[0049] The amplitude of the high-frequency vibration scraper 13 is 0.3 - 0.8 mm / s, the frequency is 10 - 15 times / min, the pulse frequency of the pulse vibration material remover 8 is 10 - 15 times / min, the stroke of the liftable and rotatable scraper 14 is 500 - 800 mm / s, and the rotation speed is 20 - 30 rpm.

[0050] Working principle and process:

[0051] When collecting gas materials, the gas materials enter the interior of the kettle body 1 through the air inlet 11, liquid nitrogen enters the liquid nitrogen sprayer 2 through the liquid nitrogen pipeline 12, and is sprayed through a number of spray nozzles 10 at different heights. After the gas materials enter the interior of the kettle body 1, they will be dispersed. The spray nozzles 10 near the air inlet 11 are higher, and can first contact with most of the gas materials when the gas materials enter the kettle body 1. Subsequently, the spray nozzles 10 far from the air inlet 11 can further contact with the dispersed gas materials to improve the heat exchange efficiency. The solid materials after sublimation fall to the lower part of the kettle body 1, are broken by the primary stirrer 3, the crusher 4 and the secondary stirrer 5, and are discharged through the discharge port 6. The nitrogen gas and non-condensable gas generated by heat exchange are discharged from the air outlet 7; during the collection process, the solid products adhered to the kettle wall are removed by the material removal assembly and discharged from the discharge port 6 together with other solid materials; different material removal assemblies can be selected according to the characteristics of the materials during the material collection process to further improve the collection efficiency.

[0052] The utility model can be used for the collection of substances such as isophthalonitrile, chlorothalonil and aluminum chloride; the utility model simplifies the main structure, avoids the influence of the wall structure on heat exchange, improves the heat exchange efficiency, and further reduces the heat load.

Claims

1. A cryogenic capture device based on liquid nitrogen cooling, comprising a kettle (1), characterized in that: A liquid nitrogen pipeline (12) and an air outlet (7) are arranged on the top of the kettle body (1); a liquid nitrogen sprayer (2) is arranged inside the kettle body (1); the liquid nitrogen pipeline (12) passes through the top of the kettle body (1) and is connected to the liquid nitrogen sprayer (2); an air inlet (11) is arranged on the side wall of the kettle body (1); a primary agitator (3), a crusher (4) and a secondary agitator (5) are arranged in sequence from top to bottom at the lower part of the kettle body (1); a material removal component is arranged on the kettle body (1); and a material outlet (6) is arranged at the bottom of the kettle body (1).

2. The cryogenic capture device based on liquid nitrogen cooling according to claim 1, characterized in that: The bottom of the kettle body (1) is arranged in a funnel shape.

3. The cryogenic capture device based on liquid nitrogen cooling according to claim 1, characterized in that: The liquid nitrogen sprayer (2) is arranged in a disc shape, and the gas outlet (7) passes through the middle of the liquid nitrogen sprayer (2) and extends to the middle of the kettle body (1).

4. The cryogenic capture device based on liquid nitrogen cooling according to claim 1, characterized in that: The liquid nitrogen sprayer (2) is provided with a plurality of spray ports (10), and the plurality of spray ports (10) are gradually extended from an end close to the air inlet (11) to an end far from the air inlet (11) and are arranged in a ladder pattern.

5. The cryogenic capture device based on liquid nitrogen cooling according to claim 1, characterized in that: A heat-insulating layer (9) is provided on the outside of the kettle body (1).

6. The cryogenic capture device based on liquid nitrogen cooling according to claim 1, characterized in that: The primary agitator (3), the crusher (4) and the secondary agitator (5) are respectively arranged horizontally at the lower part of the kettle body (1) via a rotating shaft.

7. The cryogenic capture device based on liquid nitrogen cooling according to claim 6, characterized in that: Furthermore, the rotating shafts of the primary agitator (3), the crusher (4) and the secondary agitator (5) all pass through the kettle body (1) and are connected to motors.

8. The cryogenic capture device based on liquid nitrogen cooling according to claim 1, characterized in that: The material removal component comprises a pulse vibration material remover (8), a high-frequency vibration scraper (13), and a lifting and rotating scraper (14).

9. The cryogenic capture device based on liquid nitrogen cooling according to claim 8, characterized in that: The pulse vibration remover (8) is arranged on the outer wall of the kettle body (1), the high-frequency vibration scraper (13) is arranged on the inner wall of the kettle body (1), and the liftable rotating scraper (14) is fixed on the inner top of the kettle body (1).

10. The cryogenic capture device based on liquid nitrogen cooling according to claim 8, characterized in that: The amplitude of the high-frequency vibration scraper (13) is 0.3-0.8 mm / s, the frequency is 10-15 times / min, the pulse frequency of the pulse vibration remover (8) is 10-15 times / min, the stroke of the lifting and rotating scraper (14) is 500-800 mm / s, and the rotation speed is 20-30 rpm.

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