Tail gas recovery device of dry ice production equipment

Abstract

The utility model belongs to the storage or distribution technical field of gas or liquid, concretely relates to a tail gas recovery device of dry ice production equipment, the tail gas recovery device includes cooling cavity main part, seal connection subassembly and airflow guide component, cooling cavity main part includes the concentric ring cover setting outer layer pipe and inner layer pipe, and is equipped with spiral flow guide groove on the inner wall of inner layer pipe, and the cooling medium passage is formed between outer layer pipe and inner layer pipe, seal connection subassembly includes air inlet pipeline, flange connecting portion and bellows compensator, airflow guide component includes rectifier grid and positioning pin, the utility model provides a tail gas recovery device of dry ice production equipment, solves the connection of cooling cavity and air inlet pipeline in prior art under the extremely low temperature environment because of thermal expansion and cold shrinkage effect leads to the technical problem of sealing failure, and the inner wall of cooling cavity adopts straight -through formula flow passage design and leads to the technical problem of uneven airflow distribution.

Description

Technical Field

[0001] This utility model belongs to the field of gas or liquid storage or distribution technology, and specifically relates to a tail gas recovery device for dry ice production equipment. Background Technology

[0002] Dry ice production involves rapidly expanding liquid carbon dioxide into solid carbon dioxide under specific conditions. This process generates a large amount of incompletely converted carbon dioxide exhaust gas. Directly releasing this exhaust gas into the atmosphere not only wastes resources but also increases greenhouse gas emissions. Therefore, modern dry ice production equipment is generally equipped with exhaust gas recovery devices to reintroduce the exhaust gas into the production system for recycling. In existing technologies, the exhaust gas recovery device of dry ice production equipment mainly consists of an air inlet pipe, a cooling chamber, and a filtration system. Among these, the cooling chamber, as the core component, is responsible for further cooling the carbon dioxide exhaust gas, which is at a temperature of approximately -20°C, to below -78.5°C, converting it into solid dry ice. However, in practical applications, the existing cooling chamber structure has two prominent technical defects.

[0003] The connection between the cooling chamber and the intake pipe uses a conventional flange connection structure. Under extreme low temperature environments, the thermal expansion and contraction effect can easily lead to seal failure, which seriously affects the recovery efficiency. Although some manufacturers have tried to use thicker sealing gaskets, this simple improvement cannot solve the dynamic sealing problem under temperature cycle changes and increases the difficulty of disassembly and maintenance. In addition, the existing cooling chamber inner wall mostly adopts a straight-through flow channel design, which leads to uneven airflow distribution. Some exhaust gas will form an airflow short circuit along the inner wall of the chamber and be discharged without fully contacting the cooling surface, resulting in low heat exchange efficiency. Although some technical solutions propose to add fixed baffles in the chamber, this type of design is prone to stress concentration under low temperature environments, leading to structural cracking, and cannot adjust the airflow state according to actual working conditions.

[0004] The two problems mentioned above are technically related: seal failure leads to cooling medium leakage, further reducing cooling efficiency; while low cooling efficiency prolongs equipment operating time and exacerbates temperature cycling stress on the sealing structure. Therefore, the existing design approach that treats these two problems separately cannot fundamentally solve the problem of low exhaust gas recovery efficiency in dry ice production equipment. Utility Model Content

[0005] This utility model provides a tail gas recovery device for dry ice production equipment to solve the technical problems in the prior art, such as the failure of the seal at the connection between the cooling cavity and the air inlet pipe due to thermal expansion and contraction in extreme low temperature environments, and the uneven airflow distribution caused by the straight-through flow channel design on the inner wall of the cooling cavity.

[0006] To solve the above problems, the exhaust gas recovery device for dry ice production equipment provided by this utility model adopts the following technical solution:

[0007] A waste gas recovery device for dry ice production equipment includes:

[0008] The cooling chamber body includes an outer tube and an inner tube arranged in concentric rings. The inner wall of the inner tube is provided with a spiral guide groove. A cooling medium channel is formed between the outer tube and the inner tube. The inlet and outlet of the cooling medium channel are respectively located on the side walls near both ends of the cooling chamber body. The inlet and outlet of the cooling medium channel are connected to the outer tube through radial connecting pipes. In addition, the end of the cooling chamber body near the inlet of the cooling medium channel is configured as the gas inlet end, and the end of the cooling chamber body near the outlet of the cooling medium channel is configured as the gas outlet end.

[0009] A sealing connection assembly is disposed at the gas inlet end of the main body of the cooling chamber. The sealing connection assembly includes an air inlet pipe, a flange connection, and a bellows compensator. The air inlet pipe is a cylindrical pipe with an outer diameter that matches the outer diameter of the end of the main body of the cooling chamber and an inner diameter that matches the inner diameter of the inner tube. Both ends of the air inlet pipe are welded with an annular flange structure that matches the structure of the flange connection.

[0010] In addition, the bellows compensator is a flexible metal bellows with axial expansion and contraction capability. On the air intake pipe, one end of the bellows compensator is welded to the radial outer edge of the flange connection near the main body of the cooling chamber, and the other end of the bellows compensator is welded to the outer wall of the outer tube.

[0011] Preferably, in the main body of the cooling chamber, the spiral guide groove extends continuously in a spiral shape along the length direction of the inner tube, and extends spirally from the gas inlet end to the gas outlet end of the main body of the cooling chamber. The depth of the spiral guide groove is gradually changing and gradually decreases along the airflow direction between the gas inlet end and the gas outlet end, forming a smooth depth slope.

[0012] Preferably, the sealing connection assembly further includes an inner rubber sealing ring and an outer metal spiral sealing ring, wherein the flange structure at both ends of the air intake pipe is provided with an annular groove along the circumferential direction, and an inner rubber sealing ring is provided inside the annular groove. The inner rubber sealing ring is embedded in the annular groove, and the protruding part of the inner rubber sealing ring forms a tight surface contact with the end face of the flange connection, thus forming the main sealing line.

[0013] In addition, the flange connection has multiple through holes evenly spaced along the circumference for flange bolts to pass through, and the flange structure and the flange connection are connected by the flange bolts. The outer metal spiral sealing ring is located between the flange connection and the flange structure at the end of the air intake pipe.

[0014] Preferably, the exhaust gas recovery device of the dry ice production equipment further includes an airflow guiding component. The airflow guiding component is located at the gas outlet end of the main body of the cooling chamber. The airflow guiding component includes a rectifier grid and a positioning pin. The rectifier grid is composed of several stainless steel bars, which are arranged radially and evenly from the center point to form a disc-shaped grid structure. The overall diameter of the rectifier grid matches the inner diameter of the inner tube. The positioning pin is embedded in a radial hole preset on the inner wall of the inner tube. After passing through the corresponding hole preset on the rectifier grid, the positioning pin cooperates with the radial hole, thereby fixing the rectifier grid and the inner tube together.

[0015] The beneficial effects of this utility model are as follows:

[0016] The exhaust gas recovery device of this utility model for dry ice production equipment achieves dynamic matching between airflow velocity and cooling efficiency through the gradual depth design of the spiral guide channel. The deeper guide channel in the high-temperature inlet area increases the airflow residence time, while the shallower guide channel in the low-temperature outlet area avoids energy waste caused by over-cooling.

[0017] Furthermore, the coordinated operation of the bellows compensator and the double-layer sealing ring forms a temperature-adaptive sealing system. When the temperature drops, the bellows compensator compresses and the compensation material contracts, while the inlet depth of the spiral guide groove increases, ensuring that the sealing surface is always in optimal contact. The combined design of the inner rubber sealing ring and the outer metal spiral sealing ring takes into account both low-temperature elasticity and high-temperature stability. The rubber maintains good elasticity at -78.5℃ to ensure the initial sealing effect, while the outer metal spiral sealing ring provides stable sealing pressure during temperature cycling, extending service life. On this basis, the setting of the rectifier grid effectively eliminates the rotational kinetic energy of the outlet airflow, making the airflow evenly distributed and reducing energy loss caused by local eddies. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0020] Figure 2 This is a cross-sectional view of the overall structure of this utility model;

[0021] Figure 3 This is another schematic diagram of the overall structure of this utility model;

[0022] Figure 4 This is a schematic diagram of the specific structure of the gas outlet end in this utility model. Detailed Implementation

[0023] 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.

[0024] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model; the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0025] An embodiment of this utility model provides a tail gas recovery device for dry ice production equipment, such as... Figure 1 As shown, the exhaust gas recovery device mainly includes a cooling chamber body 1, a sealing connection assembly 6, and an airflow guiding assembly 12. The components are connected and arranged in a specific structural form.

[0026] Specifically, such as Figure 1As shown, the main body 1 of the cooling chamber is a centrally symmetrical cylindrical structure, constructed with double-layer stainless steel tubes. The main body 1 is composed of an outer tube 2 and an inner tube 3 arranged concentrically. The outer tube 2 is a cylindrical tube, typically made of 304 stainless steel, which has excellent low-temperature toughness and corrosion resistance, and has smooth inner and outer surfaces. The inner tube 3 is also a cylindrical tube, made of 304 stainless steel. The outer tube 2 and the inner tube 3 are precisely positioned coaxially, forming an annular cooling medium channel 4 between them. The cooling medium channel 4 constitutes a closed space for the flow of cooling medium. The inlet and outlet of the cooling medium channel 4 are respectively located on the side walls near both ends of the main body 1 of the cooling chamber. Each inlet and outlet is connected to the outer tube 2 through a radial connecting pipe 15, which is sealed to the external cooling medium pipeline. In addition, the end of the main body 1 near the inlet of the cooling medium channel 4 is configured as the gas inlet end, and the end of the main body 1 near the outlet of the cooling medium channel 4 is configured as the gas outlet end.

[0027] like Figure 2 , Figure 4 As shown, the inner wall surface of the inner tube 3 is provided with a spiral guide groove 5. The spiral guide groove 5 extends in a continuous spiral shape along the length direction of the inner tube 3, extending spirally from the gas inlet end of the cooling cavity body 1 to the gas outlet end. The depth of the spiral guide groove 5 is designed to be gradually decreasing, and gradually decreases along the airflow direction between the gas inlet end and the gas outlet end, forming a smooth depth slope. The design of the spiral guide groove 5 allows the airflow to advance along the spiral path, increasing the residence time and heat exchange area of ​​the airflow in the inner tube 3. In addition, the end of the spiral guide groove 5 is fixedly connected to the airflow guide assembly 12.

[0028] like Figure 1-3 As shown, the sealing connection assembly 6 is located at the gas inlet end of the cooling chamber body 1 and is responsible for reliably and airtightly connecting the external air intake pipe 7 to the cooling chamber body 1. The sealing connection assembly 6 consists of multiple cooperating components, including the air intake pipe 7, the flange connection part 8, the inner rubber sealing ring, the bellows compensator 10, and the outer metal spiral sealing ring 11.

[0029] Specifically, the intake pipe 7 is a cylindrical pipe with an outer diameter that matches the outer diameter of the end of the cooling chamber body 1 and an inner diameter that matches the inner diameter of the inner tube 3. Both ends of the intake pipe 7 are provided with an annular groove along the circumferential direction. An inner rubber sealing ring is provided inside the annular groove. Both ends of the intake pipe 7 are welded with an annular flange structure, which matches the structure of the flange connection part 8.

[0030] The inner rubber sealing ring is precisely embedded in the annular groove at the end of the air intake pipe 7. The protruding part of the inner rubber sealing ring forms a tight surface contact with the end face of the flange connection part 8, which constitutes the main sealing line. This surface contact sealing method relies on the elastic deformation of the rubber to fill the microscopic unevenness and achieve a high-efficiency seal.

[0031] The flange connection 8 has multiple through holes evenly spaced along the circumference for passing through the flange bolts 16. On the air intake pipe 7, the outer radial edge of the flange connection 8 near the cooling chamber body 1 is firmly connected to one end of the bellows compensator 10 by annular welding. This welded connection ensures the structural integrity and airtightness between the flange connection 8 and the bellows compensator 10.

[0032] The bellows compensator 10 is a flexible metal bellows with axial expansion and contraction capability. The other end of the bellows compensator 10 is connected to the outer wall of the cooling cavity body 1, specifically the outer wall of the end of the outer tube 2, by welding. This connection method makes the bellows compensator 10 a flexible connection part between the sealing connection assembly 6 and the cooling cavity body 1.

[0033] Based on the above embodiments, when the ambient temperature drops significantly from 25°C to -78.5°C required for dry ice production, the bellows compensator 10 will automatically compress under this temperature change to compensate for the relative axial displacement between the connecting parts and ensure continuous tight contact of the sealing interface.

[0034] The outer metal spiral wound sealing ring 11 is located between the flange connection 8 and the flange structure at the end of the air inlet pipe 7. The outer metal spiral wound sealing ring 11 is composed of alternating winding of 316L stainless steel strip and flexible graphite strip. The stainless steel strip provides structural strength and resilience, while the flexible graphite provides excellent sealing performance and corrosion resistance.

[0035] like Figure 4 As shown, the airflow guiding assembly 12 is installed at the gas outlet end of the cooling chamber body 1 and is fixedly connected to the end of the spiral guide groove 5. The airflow guiding assembly 12 mainly includes a rectifier grid 13 and a positioning pin 14.

[0036] The rectifier grid 13 is composed of several stainless steel bars arranged radially and uniformly, radiating outward from a central point to form a disc-shaped grid structure. The overall diameter of the rectifier grid 13 matches the inner diameter of the inner tube 3. The positioning pin 14 is a cylindrical pin that is precisely embedded in the radial holes in the inner wall of the cooling chamber body 1. These radial holes are pre-set on the inner wall of the inner tube 3. After the positioning pin 14 passes through the corresponding pre-set holes on the rectifier grid 13, it engages with the radial holes, thereby firmly fixing the rectifier grid 13 and the inner tube 3 together. This fixed connection method allows the rectifier grid 13 to maintain a stable position under the action of airflow, avoiding vibration or displacement, thereby achieving effective guidance and stabilization of the airflow at the gas outlet.

[0037] In general, the exhaust gas recovery device of the dry ice production equipment of this utility model achieves dynamic matching between airflow speed and cooling efficiency through the depth gradient design of the spiral guide channel 5. The deeper guide channel in the high-temperature inlet area increases the airflow residence time, while the shallower guide channel in the low-temperature outlet area avoids energy waste caused by excessive cooling.

[0038] Furthermore, the bellows compensator 10 and the double-layer sealing ring work together to form a temperature-adaptive sealing system. When the temperature drops, the bellows compensator 10 compresses and compensates for the shrinkage of the material, while the inlet depth of the spiral guide groove 5 increases, ensuring that the sealing surface is always in the best contact state. The combined design of the inner rubber sealing ring and the outer metal spiral sealing ring 11 takes into account both low-temperature elasticity and high-temperature stability. The rubber maintains good elasticity at -78.5℃ to ensure the initial sealing effect, while the outer metal spiral sealing ring 11 provides a stable sealing specific pressure during temperature cycling to extend service life. On this basis, the setting of the rectifier grid 13 effectively eliminates the rotational kinetic energy of the outlet airflow, making the airflow evenly distributed and reducing the energy loss caused by local eddies.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A tail gas recovery device for dry ice production equipment, characterized in that, include: The cooling chamber body includes an outer tube and an inner tube arranged in concentric rings. The inner wall of the inner tube is provided with a spiral guide groove. A cooling medium channel is formed between the outer tube and the inner tube. The inlet and outlet of the cooling medium channel are respectively located on the side walls near both ends of the cooling chamber body. The inlet and outlet of the cooling medium channel are connected to the outer tube through radial connecting pipes. In addition, the end of the cooling chamber body near the inlet of the cooling medium channel is configured as the gas inlet end, and the end of the cooling chamber body near the outlet of the cooling medium channel is configured as the gas outlet end. A sealing connection assembly is disposed at the gas inlet end of the main body of the cooling chamber. The sealing connection assembly includes an air inlet pipe, a flange connection, and a bellows compensator. The air inlet pipe is a cylindrical pipe with an outer diameter that matches the outer diameter of the end of the main body of the cooling chamber and an inner diameter that matches the inner diameter of the inner tube. Both ends of the air inlet pipe are welded with an annular flange structure that matches the structure of the flange connection. In addition, the bellows compensator is a flexible metal bellows with axial expansion and contraction capability. On the air intake pipe, one end of the bellows compensator is welded to the radial outer edge of the flange connection near the main body of the cooling chamber, and the other end of the bellows compensator is welded to the outer wall of the outer tube.

2. The exhaust gas recovery device for dry ice production equipment according to claim 1, characterized in that: In the main body of the cooling chamber, the spiral guide groove extends continuously in a spiral shape along the length of the inner tube and extends spirally from the gas inlet end to the gas outlet end of the main body of the cooling chamber. The depth of the spiral guide groove is gradually changing and gradually decreases along the airflow direction between the gas inlet end and the gas outlet end, forming a smooth depth slope.

3. The exhaust gas recovery device for dry ice production equipment according to claim 1, characterized in that: The sealing connection assembly further includes an inner rubber sealing ring and an outer metal spiral sealing ring. The flange structure at both ends of the air intake pipe is provided with an annular groove along the circumferential direction. The inner rubber sealing ring is provided inside the annular groove. The inner rubber sealing ring is embedded in the annular groove. The protruding part of the inner rubber sealing ring forms a tight surface contact with the end face of the flange connection, which constitutes the main sealing line. In addition, the flange connection has multiple through holes evenly spaced along the circumference for flange bolts to pass through, and the flange structure and the flange connection are connected by the flange bolts. The outer metal spiral sealing ring is located between the flange connection and the flange structure at the end of the air intake pipe.

4. The exhaust gas recovery device for dry ice production equipment according to claim 1, characterized in that: The exhaust gas recovery device of the dry ice production equipment also includes an airflow guiding component. The airflow guiding component is located at the gas outlet end of the main body of the cooling chamber. The airflow guiding component includes a rectifier grid and a positioning pin. The rectifier grid is composed of several stainless steel bars, which are arranged radially and evenly from the center point to form a disc-shaped grid structure. The overall diameter of the rectifier grid matches the inner diameter of the inner tube. The positioning pin is embedded in a radial hole preset on the inner wall of the inner tube. After passing through the corresponding hole preset on the rectifier grid, the positioning pin cooperates with the radial hole, thereby fixing the rectifier grid and the inner tube together.

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