Recovery device of chloroethane in production of photoinitiator TPO (Thermoplastic Polyolefin)

Abstract

The embodiment of the utility model provides a recovery device for chloroethane in production of a photoinitiator TPO. The recovery device comprises a chloroethane steam collecting pipe, a first-stage condenser and a second-stage condenser which are communicated in sequence, the gas-liquid separator is arranged between the first-stage condenser and the second-stage condenser, and the gas-liquid separator is communicated with the first-stage condenser and the second-stage condenser; the recovery tank is communicated to the secondary condenser through a liquid pipe to receive chloroethane liquid; the air suction device is connected to the gas-liquid separator through a gas rising pipe, and the gas rising pipe is provided with a vertical part. According to the recovery device provided by the embodiment of the invention, chloroethane can be completely condensed at least, the recovery efficiency is improved, and pollution to the environment is avoided.

Description

Technical Field

[0001] This application relates to the field of chemical technology, specifically to a device for recovering chloroethane in the production of photoinitiator TPO. Background Technology

[0002] 2,4,6-Trimethylbenzoyl-diphenylphosphine oxide (TPO) is one of the most widely used acylphosphine oxide initiators, exhibiting high photoinitiation activity. Due to the adjacent positions of the reactive carbonyl and phosphonyl groups, the molecule is highly reactive, generating benzoyl and phosphoryl radicals upon light irradiation to initiate polymerization. It has a wide absorption range and fast photocuring speed. Furthermore, this compound also possesses photobleaching properties, preventing yellowing of coatings. Its excellent absorption performance makes it widely used in various coatings, such as screen printing inks, offset printing inks, flexographic printing inks, and wood coatings, particularly suitable for low-yellowing and white systems.

[0003] The production process generates chloroethane, which is an extremely flammable gas and may be carcinogenic. It needs to be recycled to reduce production costs and protect industrial safety while minimizing environmental pollution.

[0004] However, the existing technology has the following problems:

[0005] 1. During the condensation and recovery process of chloroethane, the untimely discharge of chloroethane may cause side reactions, affecting normal production;

[0006] 2. During the condensation and recovery of chloroethane, incomplete condensation may cause some chloroethane vapor to leak out. If this chloroethane vapor leaks out, it will not only reduce the recovery efficiency and cause potential production safety hazards, but also pollute the environment.

[0007] 3. Most of the recovered chloroethane will fall into the recovery unit. It is especially important to fix the recovery unit and prevent spills. If the unit is unstable, chloroethane is prone to leakage, which will cause pollution of chloroethane and affect the recovery efficiency. Utility Model Content

[0008] In view of the above-mentioned problems in the prior art, the embodiments of this application propose a chloroethane recovery device in the production of photoinitiator TPO. This recovery device can at least ensure that chloroethane is completely condensed, thereby improving the recovery efficiency and avoiding environmental pollution.

[0009] According to one aspect of this application, a device for recovering chloroethane in the production of photoinitiator TPO is provided. The recovery device includes: a chloroethane vapor collection pipe, a primary condenser, and a secondary condenser connected in sequence; a gas-liquid separator disposed between the primary and secondary condensers and connecting the primary and secondary condensers; a recovery tank connected to the secondary condenser via a liquid pipe to receive chloroethane liquid; and a suction device connected to the gas-liquid separator via a riser pipe having a vertical section.

[0010] In some embodiments, one end of the gas-liquid separator is directly connected to the primary condenser, while the other end is connected to the secondary condenser via a connecting pipe.

[0011] In some embodiments, the suction device is an induced draft fan; preferably, the suction device is an induced draft fan with a power of 1.2-3 kW, more preferably, the suction device is an induced draft fan with a power of 2.2 kW.

[0012] In some embodiments, the temperature of the refrigerant in the primary condenser is -7°C to 0°C, and the temperature of the refrigerant in the secondary condenser is -30°C to -25°C.

[0013] In some embodiments, the recovery device further includes a sleeve covering the vertical portion of the riser pipe, with a refrigerant between the sleeve and the outer wall of the vertical portion.

[0014] In some embodiments, the suction device is positioned above the primary condenser.

[0015] In some embodiments, the recovery device further includes a nitrogen connection pipe for supplying nitrogen to the recovery device.

[0016] In some embodiments, the recycling device further includes a sealing seat disposed at the connection between the liquid pipe and the recycling tank.

[0017] In some embodiments, the recycling tank is provided with a safety valve having an outlet, which is connected to a suction device via a tailpipe.

[0018] In some embodiments, the recycling device further includes a finished product tank connected to the recycling tank, the finished product tank being connected to the cylinder via a hose.

[0019] Preferably, in some embodiments, an overflow port is provided between the finished product tank and the recycling tank.

[0020] In some embodiments, the cylinder is mounted on a weighing device.

[0021] Preferably, in some embodiments, the cylinder is mounted on the weighing device via a cylinder support.

[0022] The beneficial technical effects of this utility model are as follows:

[0023] The recovery device in the embodiments of this application can at least ensure the timely discharge of chloroethane vapor. The recovery device in the embodiments of this application can at least ensure complete condensation of chloroethane, thereby improving recovery efficiency and preventing environmental pollution. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It is worth noting that, according to industry standard practice, the various components are not drawn to scale and are only used for illustrative purposes. In fact, for the sake of clarity of discussion, the dimensions of the various components can be arbitrarily increased or decreased.

[0025] Figure 1 This is a schematic diagram of a chloroethane recovery device in the production of photoinitiator TPO according to an embodiment of this application.

[0026] Figure 2 This is a schematic diagram of a chloroethane recovery device in the production of photoinitiator TPO according to another embodiment of this application.

[0027] Figure 3 This is a schematic diagram of a chloroethane recovery device in the production of photoinitiator TPO according to another embodiment of this application.

[0028] Figure 4 This is a schematic diagram of a chloroethane recovery device in the production of photoinitiator TPO according to another embodiment of this application. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0030] The following disclosure provides numerous different embodiments or instances for implementing various features of the provided subject matter. Specific examples of elements and arrangements will be described below to simplify the present invention. These are merely examples and are not intended to limit the present invention. For example, in the following description, the first component above or on the second component may include embodiments where the first and second components are in direct contact, or embodiments where an additional component exists between the first and second components such that the first and second components are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in various instances of the present invention. Such repetition is merely for brevity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0031] Furthermore, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific structures shown in the figures are merely illustrative and are not intended to limit the scope of this application. Other structures not described in the figures may be provided according to actual needs when describing specific figures, and are not intended to limit the scope of this application.

[0032] Figure 1 This is a schematic diagram of a chloroethane recovery device in the production of the photoinitiator TPO according to an embodiment of this application. (Reference) Figure 1As shown, according to some embodiments of this application, the recovery device may include: a chloroethane vapor collection pipe 2, a primary condenser 3, and a secondary condenser 5 connected in sequence; a gas-liquid separator 4 disposed between the primary condenser 3 and the secondary condenser 5, and the gas-liquid separator 4 connecting the primary condenser 3 and the secondary condenser 5; a recovery tank 7 connected to the secondary condenser 5 via a liquid pipe 6 to receive chloroethane liquid; and a suction device 9 connected to the gas-liquid separator 4 via a riser pipe 10, wherein the riser pipe 10 has a vertical portion 101. The chloroethane recovery device in the photoinitiator TPO production of embodiments of this application includes a suction device 9, which can draw chloroethane vapor from the recovery device. The suction device 9 provides suction force to draw chloroethane vapor from the gas-liquid separator 4 (i.e., the suction direction is from the gas-liquid separator 4 to the suction device 9). Since the gas-liquid separator 4, the primary condenser 3, and the chloroethane vapor collection pipe 2 are connected, at least the chloroethane vapor can be discharged in a timely manner. The recycling device of the embodiments of this application includes a primary condenser 3 and a secondary condenser 5, which can at least ensure that chloroethane is completely condensed, thereby improving recycling efficiency and avoiding environmental pollution. Furthermore, if the suction device 9 is positioned too close to the chloroethane vapor collection pipe 2, or if the suction device 9 is positioned too close to the reactor 1 connected to the chloroethane vapor collection pipe 2, it will pose a safety risk of explosive boiling of the material during the peak of the reaction. At the same time, excessive chloroethane vapor will be extracted per unit time, exceeding the load of the condenser, which will directly reduce the condensation effect and the recovery rate. If hot chloroethane vapor is directly drawn into the condenser, it will damage the equipment, consume a lot of energy, and the condensation effect will not be good. In the recovery device of this application embodiment, the suction device 9 is connected to the gas-liquid separator 4 through the riser pipe 10. The gas-liquid separator 4 is set between the primary condenser 3 and the secondary condenser 5, which can ensure the safety of the recovery process and also reserve a buffer time for the condensation process of chloroethane vapor, thereby improving the condensation efficiency of the condenser. The chloroethane vapor drawn into the riser pipe 10 after passing through the gas-liquid separator 4 can condense during the process of climbing the vertical part 101 of the riser pipe 10 and fall back into the gas-liquid separator 4 and enter the secondary condenser 5.

[0033] It should be understood that the gas-liquid separator 4 is located between the primary condenser 3 and the secondary condenser 5. The gas-liquid separator 4 can be directly connected to the primary condenser 3 and / or the secondary condenser 5, or it can be indirectly connected to the primary condenser 3 and / or the secondary condenser 5 via connecting pipes. Figure 1As shown, one end of the gas-liquid separator 4 is directly connected to the primary condenser 3 (the gas-liquid separator 4 and the primary condenser 3 are in physical contact), and the other end of the gas-liquid separator 4 is connected to the secondary condenser 5 through a connecting pipe (the gas-liquid separator 4 can be indirectly connected to the secondary condenser 5 through a connecting pipe). In other embodiments, the primary condenser 3 can be directly connected to a connecting pipe, the connecting pipe can be connected to the gas-liquid separator 4, and the gas-liquid separator 4 can be connected to a connecting pipe to the secondary condenser 5. As long as the gas-liquid separator 4 can connect the primary condenser 3 and the secondary condenser 5, this application is not limited to the embodiments shown in the figure. Those skilled in the art can arrange and combine the direct and indirect connection methods according to actual needs.

[0034] In some embodiments, the suction device 9 is an induced draft fan. Preferably, the suction device 9 is an induced draft fan with a power of 1.2-3 kW, and more preferably, the suction device 9 is an induced draft fan with a power of 2.2 kW. The power setting of the induced draft fan in the embodiments of this application is to provide a certain traction / suction force to help chloroethane vapor be discharged from the reactor 1 in a timely manner, without being too large and causing chloroethane vapor to be directly discharged into the environment.

[0035] In some embodiments, the temperature of the refrigerant in the primary condenser 3 is -7°C to 0°C, and the temperature of the refrigerant in the secondary condenser 5 is -30°C to -25°C. In a preferred embodiment, the temperature of the refrigerant in the primary condenser 3 is 0°C, and the temperature of the refrigerant in the secondary condenser 5 is -25°C. The recovery device of the embodiments of this application includes two-stage condensers, and a gas-liquid separator 4 is provided after the primary condenser 3. Most of the chloroethane vapor is cooled into chloroethane liquid by the primary condenser 3, and then further cooled in the secondary condenser 5. During the condensation process in the primary condenser 3, part of the chloroethane vapor that has not been cooled enters the riser pipe 10 connecting the gas-liquid separator 4 and the suction device 9 through the gas-liquid separator 4, and is re-condensed in the vertical part 101 of the riser pipe 10. The other part follows the chloroethane liquid into the secondary condenser 5, where it is completely cooled by the refrigerant, such as a deep refrigerant, in the secondary condenser 5. In some embodiments, the recovery device may further include a sleeve (not shown) covering the vertical portion 101 of the riser pipe 10, with a refrigerant between the sleeve and the outer wall of the vertical portion 101. The refrigerant may be, for example, circulating water, to maintain coolness and improve condensation efficiency, so that ethane vapor is condensed as it rises along the vertical portion 101 and re-enters the gas-liquid separator 4.

[0036] In some embodiments, the suction device 9 may be disposed above the primary condenser 3. It should be understood that the suction device 9 may be disposed directly above the primary condenser 3 or obliquely above the primary condenser 3.

[0037] In some embodiments, the recovery apparatus of this application may further include a nitrogen connection pipe (not shown in the figures) for supplying nitrogen to the recovery apparatus. In a preferred embodiment, refer to Figure 1 As shown, the chloroethane vapor collection pipe 2 is connected to the reactor 1 that generates chloroethane vapor. The reactor 1 may be equipped with a nitrogen connection pipe, or in other words, the nitrogen connection pipe is connected to the reactor 1 to supply nitrogen to the entire recovery device.

[0038] The recovery tank 7 in this embodiment is a recovery tank capable of preventing chloroethane spillage. In some embodiments, the recovery device of this embodiment may further include a sealing seat (not shown), which may be disposed at the connection between the liquid pipe 6 and the recovery tank 7. In some embodiments, the sealing seat is a base disposed at the connection between the liquid pipe 6 and the recovery tank 7 to provide a sealing function, and may have any shape and structure known to those skilled in the art. The presence of the sealing seat allows the condensed chloroethane liquid to be introduced into the recovery tank 7 while maintaining the good sealing of the recovery tank 7. The sealing seat may be disposed at the center of the top of the recovery tank 7.

[0039] In some embodiments, a tank jacket 8 may be provided outside the recycling tank 7, and the tank jacket 8 may be a -(7-10)℃ freezing medium.

[0040] In some embodiments, a pressure detector 21 and a thermometer 22 may be provided inside the recycling tank 7, for example on the top wall of the recycling tank 7.

[0041] Figure 2 This is a schematic diagram of a chloroethane recovery device in the production of the photoinitiator TPO according to another embodiment of this application. (Reference) Figure 2 As shown, in some embodiments, the recovery tank 7 may also be equipped with a safety valve 11 having an outlet 12, which is connected to the suction device 9 via a tail gas pipe 13. Due to the presence of the safety valve 11 and the tail gas pipe 13 connected to the suction device 9, rapid pressure relief can be achieved. In the event of an accident, if a large amount of uncondensed ethane vapor rushes into the recovery tank 7, the safety valve 11 can open, and the suction device 9 will draw the ethane vapor from the outlet 12 into the tail gas pipe 13 for discharge. In some preferred embodiments, the safety valve 11 is located at the top of the recovery tank 7.

[0042] Figure 3 This is a schematic diagram of a chloroethane recovery device in the production of the photoinitiator TPO according to another embodiment of this application. (Reference) Figure 3As shown, in some embodiments, the recycling device may further include a finished product tank 15 connected to the recycling tank 7, which is connected to a steel cylinder 17 via a hose 16. The finished product tank 15 can store chloroethane liquid from the recycling tank 7 and then fill it into the steel cylinder 17. The finished product tank 15 is connected to the recycling tank 7 via a connecting pipe, which may have a valve to control the flow rate of the chloroethane liquid. Although Figure 3 In the embodiment shown, the connection point between the connecting pipe of the finished product tank 15 and the recycling tank 7 and the recycling tank 7 is at the top of the recycling tank 7. It should be understood that in other embodiments, the connection point between the connecting pipe and the recycling tank 7 can be at any suitable location in the recycling tank 7. In addition, a pipe can be provided inside the recycling tank 7 to allow the chloroethane liquid in the recycling tank 7 to smoothly enter the finished product tank 15. When the chloroethane liquid in the recycling tank 7 needs to be filled, the cylinder 17 is connected with a hose 16, and the relevant valves and pumps can be opened for filling operations. The use of a hose 16 connection facilitates easier replacement of the cylinder 17. Preferably, in some embodiments, an overflow port 14 can be provided between the finished product tank 15 and the recycling tank 7. The entire connecting pipe of the recycling device, the finished product tank 15, the hose 16, and the cylinder 17 can all have an insulation layer, and the finished product tank 15 can be electrostatically grounded.

[0043] In some embodiments, the cylinder 17 is mounted on a weighing device 20, which may be an electronic scale or weighbridge with a smart display screen 19, to directly weigh the weight of the filled ethane chloride liquid or control the filling progress. Preferably, in some embodiments, the cylinder 17 is mounted on the weighing device 20 via a cylinder support 18 to maintain the stability of the cylinder 17. The weighing device 20 is electrostatically grounded.

[0044] Figure 4 This is a schematic diagram of a chloroethane recovery device in the production of the photoinitiator TPO according to another embodiment of this application. (Reference) Figure 4 As shown, the chloroethane recovery device in the production of photoinitiator TPO according to an embodiment of this application may include: a chloroethane vapor collection pipe 2, a primary condenser 3, and a secondary condenser 5 connected in sequence; a gas-liquid separator 4 disposed between the primary condenser 3 and the secondary condenser 5, and the gas-liquid separator 4 connecting the primary condenser 3 and the secondary condenser 5; a recovery tank 7 connected to the secondary condenser 5 via a liquid pipe 6 to receive chloroethane liquid; a suction device 9 connected to the gas-liquid separator 4 via a riser pipe 10, wherein the riser pipe 10 has a vertical section 101, wherein the chloroethane vapor collection pipe 2 is connected to the reactor 1 that generates chloroethane vapor; the recovery tank 7 may also be provided with a safety valve 11 having an outlet 12, the outlet 12 being connected to the suction device 9 via a tail gas pipe 13; and a finished product tank 15 connected to the recovery tank 7, the finished product tank 15 being connected to a steel cylinder 17 via a hose 16.

[0045] Figures 1-4 Although other components besides those described in the various embodiments are shown, it should be understood that the other components and their locations, as well as the specific locations of the components shown in the figures, do not constitute a limitation on the recycling device in this embodiment. It is understood that those skilled in the art can add or remove any suitable components in the recycling device and place them in suitable locations as needed.

[0046] In the chloroethane recovery device for the photoinitiator TPO production of embodiments of this application, the chloroethane vapor collection pipe 2 is connected to the reactor 1 that generates chloroethane vapor. In some embodiments, 2,4,6-trimethylbenzoyl chloride (TS) and diphenylethoxyphosphorus (EDPP) can be added to the reactor 1 and reacted at a certain temperature. During the reaction, chloroethane vapor (the boiling point of chloroethane is 12.3°C) is generated. The product TPO and chloroethane vapor are produced in a 1:1 ratio. The more TPO converted in the reaction, the more chloroethane vapor is produced. Since the density of chloroethane vapor is greater than that of air, it precipitates on the upper part of the reactants in the reactor 1 during the reaction. By turning on the suction device 9 in the recovery device, under the induced draft of 1.2-3 kW power (preferably 2.2 kW power), the chloroethane vapor is recovered. ethane vapor is extracted from reactor 1. The extracted chloroethane vapor enters the primary condenser 3 through the chloroethane vapor collection pipe 2 for initial condensation. In the primary condenser 3, most of the chloroethane vapor produced by the reaction condenses into chloroethane liquid, which then enters the gas-liquid separator 4. A portion of the chloroethane vapor that was not cooled in the primary condenser 3 enters the riser pipe 10 connecting the suction device 9 and the gas-liquid separator 4 through the gas-liquid separator 4. It is re-condensed at the vertical part 101 of the riser pipe 10 and returns to the gas-liquid separator 4, then enters the secondary condenser 5. Another portion of the chloroethane vapor that was not cooled in the primary condenser 3 follows the chloroethane liquid through the gas-liquid separator 4 into the secondary condenser 5. The chloroethane vapor and chloroethane liquid entering the secondary condenser 5 are condensed again and completely cooled down, then enter the recovery tank 7. In other words, the chloroethane vapor generated in reactor 1 is collected into the recovery tank 7, which is designed to prevent overflow, through specific technologies such as induced draft, condensation, and separation. Samples taken from recycling tank 7 can yield chloroethane product with a purity of ≥98% and a moisture content of ≤0.01%.

[0047] The reaction temperature of 2,4,6-trimethylbenzoyl chloride (TS) and diphenylethoxyphosphorus (EDPP) in reactor 1 can be 40-70°C (the reactor temperature can be gradually increased to 70°C during the reaction). In a preferred embodiment, the reaction temperature is 50-58°C.

[0048] In some embodiments, nitrogen gas can be introduced into the nitrogen connection pipe before TPO synthesis feed, so that the entire device is in a nitrogen environment. For example, nitrogen gas can be introduced into the reactor 1 first.

[0049] In some embodiments, the chloroethane liquid in the recycling tank 7 can also be filled into the steel cylinder 17 using a filling device. For example, the valve on the connecting pipe between the recycling tank 7 and the finished product tank 15 can be opened, allowing the chloroethane liquid to enter the finished product tank 15, and then fill into the steel cylinder 17 through the hose 16 connected to the finished product tank 15. Since the finished product tank 15 and the steel cylinder 17 are connected using the hose 16, the steel cylinder 17 can be replaced conveniently and quickly. In some embodiments, the filling progress can be controlled by the weighing device 20 carrying the steel cylinder 17, and the entire filling device is kept electrostatically grounded.

[0050] The embodiments of this application overcome the shortcomings of existing industrial production technologies, providing a simple, efficient, high-recovery, and low-cost device for recovering chloroethane in the production of photoinitiator TPO. The recovery device of the embodiments of this application at least ensures the timely discharge of chloroethane vapor, which can improve the conversion efficiency of TPO (in TPO production, the less byproduct, the more the reaction equilibrium shifts towards the forward reaction). The recovery device of the embodiments of this application also ensures complete condensation of chloroethane, improving recovery efficiency, avoiding environmental pollution, and effectively implementing the national green chemical development concept.

[0051] Furthermore, in the recovery device of this application embodiment, the suction device is connected to the gas-liquid separator via a riser pipe. The gas-liquid separator is located between the primary condenser and the secondary condenser, which ensures the safety of the recovery process and also provides a buffer time for the condensation of chloroethane vapor. The chloroethane vapor enters the two-stage condenser and undergoes two stages of condensation, improving the condensation efficiency of the condenser. Specifically, the condensation device in this application consists of a two-stage condensation system. The primary stage uses chilled water (refrigerant) at approximately -7°C to 0°C, while the secondary condenser uses cryogenic water (refrigerant) at -30°C to -25°C. A gas-liquid separator is installed in the primary condenser. The primary condenser cools most of the chloroethane vapor produced by the reaction into chloroethane liquid, which is then further cooled in the secondary condenser. Part of the chloroethane vapor that was not cooled in the primary condenser is re-condensed in the vertical part of the riser pipe and re-enters the gas-liquid separator. The other part follows the chloroethane liquid into the secondary condenser and is completely cooled by the cryogenic water.

[0052] The recycling device provided in the embodiments of this application can improve the safety of industrial production technology, reduce costs and increase efficiency, protect the environment, reduce processing costs, and generate revenue.

[0053] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A device for recovering chloroethane in the production of photoinitiator TPO, characterized in that, include: A series of interconnected components: a chloroethane vapor collection pipe, a primary condenser, and a secondary condenser. A gas-liquid separator is disposed between the primary condenser and the secondary condenser, and the gas-liquid separator is connected to the primary condenser and the secondary condenser; A recovery tank is connected to the secondary condenser via a liquid pipe to receive chloroethane liquid; A suction device is connected to the gas-liquid separator via a riser pipe, the riser pipe having a vertical section.

2. The recycling device according to claim 1, characterized in that, One end of the gas-liquid separator is directly connected to the primary condenser, while the other end is connected to the secondary condenser via a connecting pipe.

3. The recycling device according to claim 1, characterized in that, The suction device is an induced draft fan.

4. The recycling device according to claim 3, characterized in that, The suction device is an induced draft fan with a power of 1.2-3kw.

5. The recycling device according to claim 4, characterized in that, The suction device is a 2.2kw induced draft fan.

6. The recycling device according to claim 1, characterized in that, The temperature of the refrigerant in the first-stage condenser is -7℃ to 0℃, and the temperature of the refrigerant in the second-stage condenser is -30℃ to -25℃.

7. The recycling device according to claim 1, characterized in that, It also includes a sleeve that covers the vertical portion of the riser pipe, and there is a refrigerant between the sleeve and the outer wall of the vertical portion.

8. The recycling device according to claim 1, characterized in that, The suction device is located above the primary condenser.

9. The recycling device according to claim 1, characterized in that, It also includes a nitrogen connection pipe for supplying nitrogen to the recovery device.

10. The recycling device according to claim 1, characterized in that, It also includes a sealing seat, which is disposed at the connection between the liquid pipe and the recovery tank.

11. The recycling device according to claim 1, characterized in that, The recycling tank is equipped with a safety valve with an outlet, which is connected to the suction device via a tailpipe.

12. The recycling device according to claim 1, characterized in that, It also includes a finished product container connected to the recycling tank, which is connected to the cylinder via a hose.

13. The recycling device according to claim 12, characterized in that, An overflow port is provided between the finished product tank and the recycling tank.

14. The recycling device according to claim 12, characterized in that, The gas cylinder is mounted on the weighing device.

15. The recycling apparatus according to claim 14, characterized in that, The gas cylinder is mounted on the weighing device via a gas cylinder bracket.

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