Safe purification and rectification equipment for preparing 1, 1, 1, 2-tetrafluoroethane

Abstract

The invention relates to the technical field of purification and rectification, in particular to safety type purification and rectification equipment for preparing 1, 1, 1, 2-tetrafluoroethane, and effectively solves the problems of scaling of a reboiler, inaccurate dosing and insufficient safety protection in an R134a purification process. Comprising a rectifying tower, an L-shaped discharging pipe is fixedly connected to the lower end of the rectifying tower, connecting pipes are arranged on the left side of the rectifying tower and the left side of the discharging pipe respectively, reversing valves are connected to the left sides of the connecting pipes, reboilers are connected to the front side and the rear side of the reversing valve on the lower side through liquid inlet pipes respectively, and the other sides of the reboilers are communicated with the reversing valve on the upper side through liquid outlet pipes; by arranging the opening and closing assembly, the reboiler can be quickly opened and closed, internal scaling and tube bundle overhauling are facilitated, the problem that a traditional reboiler is inconvenient to maintain is solved, the quantitative feeding assembly can accurately control the feeding amount of a scale inhibitor or a corrosion inhibitor, the situation that the descaling and rectifying effects are affected due to inaccurate feeding is avoided, and the service life of the reboiler is prolonged. And the descaling efficiency of the reboiler and the overall performance of the rectification device are improved.

Description

Technical Field

[0001] This invention relates to the field of purification distillation technology, specifically to a safe purification distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane. Background Technology

[0002] 1,1,1,2-Tetrafluoroethane, commonly known as R134a, is a colorless, odorless, and non-flammable halogenated hydrocarbon. It possesses excellent thermodynamic properties, exhibits high refrigeration efficiency in refrigeration systems, and has no ozone-depleting effect, making it a widely used environmentally friendly refrigerant. It is commonly used in automotive air conditioning, household air conditioning, refrigerators, and other refrigeration equipment. It can also be used as a raw material for foaming agents and aerosols. However, its preparation process generates various impurities. The presence of these impurities affects the purity and performance of 1,1,1,2-tetrafluoroethane, reducing its quality as a refrigerant or for other applications. Therefore, purification and distillation processes are necessary to remove impurities and improve product quality. Quality is paramount; as a core piece of equipment, the performance of the distillation column directly impacts separation efficiency and production efficiency. Existing distillation equipment is prone to scale and other impurities forming in the reboiler during long-term operation, affecting heat transfer efficiency. Traditional reboiler opening and closing methods are complex, making cleaning and maintenance difficult. Therefore, to prevent rapid scale formation in the reboiler, scale inhibitors or corrosion inhibitors need to be added. However, the lack of precise dosing devices easily leads to inaccurate dosages, affecting both descaling and distillation efficiency. Furthermore, existing distillation equipment lacks safety protection; abnormal pressure within the equipment cannot be addressed promptly and effectively, posing certain safety hazards. Therefore, a distillation device capable of solving these problems is urgently needed. Summary of the Invention

[0003] In view of the above situation and to overcome the defects of the prior art, the purpose of this invention is to provide a safe purification and distillation device for the preparation of 1,1,1,2-tetrafluoroethane, which effectively solves the problems of reboiler scaling, inaccurate dosing and insufficient safety protection during the purification of R134a.

[0004] The technical solution is as follows: The present invention includes a distillation column, with an L-shaped discharge pipe fixedly connected to the lower end of the distillation column. Connecting pipes are respectively provided on the left side of the distillation column and the left side of the discharge pipe. A reversing valve is connected to the left side of the connecting pipe. A reboiler is connected to the front and rear sides of the reversing valve on the lower side via liquid inlet pipes. The other side of the reboiler is connected to the reversing valve on the upper side via a liquid outlet pipe. An opening and closing assembly is provided on the left side of the reboiler to realize its opening and closing. A quantitative dispensing assembly is provided on the upper side of the liquid inlet pipe. A feed pipe is provided on the right side of the distillation column. An exhaust pipe is provided on the upper side of the distillation column. A condenser is provided in the middle of the exhaust pipe. A safety valve assembly is provided on the upper side of the condenser. A reflux pipe is provided on the lower side of the condenser. The reflux pipe is connected to the distillation column.

[0005] The reversing valve includes a sealing frame, and a two-way ball valve is rotatably connected inside the sealing frame. The two-way ball valve is used to change the direction of liquid flow. A rotating handle is fixedly connected to the upper end of the two-way ball valve. The left ends of the two reversing valves are connected through a flushing pipe, and a water pump is provided in the middle of the flushing pipe.

[0006] The opening and closing assembly includes a sealing plate, the lower side of which is hinged to the reboiler. A rubber ring is fixedly connected to the right end of the sealing plate. Rotatable lead screws are provided on the front and rear sides of the reboiler. An L-shaped lifting rod is rotatably connected to the outer wall of the lead screw. The lifting rod is slidably connected to the reboiler. Inclined grooves are provided on the front and rear sides of the sealing plate. A connecting pin located in the corresponding inclined groove is fixedly connected to the left side of the lifting rod.

[0007] A bevel gear is fixedly connected to the lower end of the lead screw, and a double-headed motor is fixedly connected to the lower end of the reboiler. A drive shaft is fixedly connected to the output end of the double-headed motor, and helical gears that can mesh with the corresponding bevel gears are fixedly connected to the front and rear sides of the drive shaft, respectively.

[0008] The quantitative dispensing component includes a dispensing tube connected to an inlet tube. A sleeve is fixedly connected to the right end of the dispensing tube, and a lifting tube that can move up and down is provided inside the sleeve. A through hole that can communicate with the dispensing tube is opened on one side of the lifting tube. A quantitative cylinder is fixedly connected to the upper end of the lifting tube, and a storage tank is provided to the right of the quantitative cylinder. A hinged ball is fixedly connected to the upper end of the quantitative cylinder and the lower end of the storage tank, respectively. A hollow telescopic tube is provided between the two hinged balls. The left and right sides of the telescopic tube are respectively hinged to the hinged balls on their corresponding sides. The storage tank and the quantitative cylinder can be connected through the telescopic tube.

[0009] A bracket located below the lifting pipe is fixedly connected to the upper side of the inlet pipe. A deflection wheel is rotatably connected to the upper side of the bracket. The deflection wheel can contact the lower end of the lifting pipe. A bevel gear is fixedly connected to the front end of the deflection wheel. A drive motor is fixedly connected to the upper side of the inlet pipe. A bevel gear is fixedly connected to the output end of the drive motor and meshes with the bevel gear.

[0010] The hinged ball has a movable groove, and the left and right sides of the telescopic tube are respectively located in the movable grooves on their corresponding sides.

[0011] A fixing frame is fixedly connected to the lower side of the storage tank, and the fixing frame is in contact with the ground.

[0012] The safety valve assembly includes a micro differential pressure transmitter located on the upper side of the condenser. A vent valve is provided on the upper side of the condenser within a radius of less than 500 mm from the micro differential pressure transmitter, and the vent valve is connected to the interior of the condenser.

[0013] A sampling tube is provided on the upper side of the gas outlet pipe, an automatic water-draining valve is provided inside the sampling tube, and a gas chromatograph is provided on one side of the sampling tube.

[0014] Beneficial effects: This invention enables the reboiler to be quickly opened and closed by setting an opening and closing component, which facilitates the cleaning of internal scale and the maintenance of the tube bundle, solving the problem of inconvenient maintenance of traditional reboilers. The quantitative dosing component can accurately control the amount of scale inhibitor or corrosion inhibitor added, avoiding the impact of inaccurate dosing on the descaling and distillation effect, thus improving the descaling efficiency of the reboiler and the overall performance of the distillation unit.

[0015] This invention enables two reboilers to work in conjunction with a reversing valve, allowing the reboilers to operate alternately and ensuring uninterrupted production. At the same time, the thermal circulation system formed by the reboilers, distillation column, and discharge pipe can effectively maintain the gas-liquid balance in the distillation process, ensuring that the distillation process is efficient and stable.

[0016] This invention, by setting up a safety valve assembly, can monitor the condenser pressure in real time and quickly release pressure when overpressure occurs, preventing safety accidents caused by excessive pressure and ensuring the safe operation of the distillation column and the entire system. In addition, the sampling tube, automatic steam trap and gas chromatograph work together to accurately sample and analyze the gas phase components of the outlet pipe and detect the concentration of non-condensable gases, further improving the safety and reliability of the device operation. Attached Figure Description

[0017] Figure 1 This is an isometric view of the present invention.

[0018] Figure 2 This is a schematic diagram of the storage tank in this invention.

[0019] Figure 3 This is a partial cross-sectional schematic diagram of the metering cylinder in this invention.

[0020] Figure 4 This is a schematic diagram of the reboiler in this invention.

[0021] Figure 5 This is a schematic diagram of the rubber ring in this invention.

[0022] Figure 6 This is a schematic diagram of the water pump in this invention.

[0023] Figure 7 This is a cross-sectional top view of the double-pass ball valve in this invention.

[0024] Figure 8 This is a partial cross-sectional front view of the double-pass ball valve in this invention.

[0025] Figure 9 This is a schematic diagram of the condenser in this invention.

[0026] In the diagram: 1. Distillation column; 2. Discharge pipe; 3. Connecting pipe; 4. Reversing valve; 5. Inlet pipe; 6. Reboiler; 7. Discharge pipe; 8. Feed pipe; 9. Gas outlet pipe; 10. Condenser; 11. Reflux pipe; 12. Sealing frame; 13. Two-way ball valve; 14. Flushing pipe; 15. Water pump; 16. Sealing plate; 17. Rubber ring; 18. Lead screw; 19. Lifting rod; 20. Inclined trough; 21. 21. Bevel gear; 22. Dual-head motor; 23. Drive shaft; 24. Helical gear; 25. Dispensing tube; 26. Sleeve; 27. Lifting tube; 28. Metering cylinder; 29. ​​Storage tank; 30. Articulated ball; 31. Telescopic tube; 32. Deflecting wheel; 33. Drive motor; 34. Movable groove; 35. Telescopic rod; 36. Micro differential pressure transmitter; 37. Vent valve; 38. Sampling tube; 39. Gas chromatograph. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] Depend on Figures 1 to 9 The distillation column 1 is provided, with an L-shaped discharge pipe 2 fixedly connected to its lower end. Connecting pipes 3 are located on the left side of the distillation column 1 and the left side of the discharge pipe 2, respectively. A reversing valve 4 is connected to the left side of the connecting pipe 3. Reboilers 6 are connected to the front and rear sides of the lower reversing valve 4 via inlet pipes 5. The other side of the reboiler 6 is connected to the upper reversing valve 4 via an outlet pipe 7. An opening / closing assembly is located on the left side of the reboiler 6. A metering component is located on the upper side of the inlet pipe 5. A feed pipe 8 is located on the right side of the distillation column 1. An outlet pipe 9 is located on the upper side of the distillation column 1. A condenser 10 is located in the middle of the outlet pipe 9. A safety valve assembly is located on the upper side of the condenser 10. A reflux pipe 11 is located on the lower side of the condenser 10, and the reflux pipe 11 is connected to the distillation column 1.

[0029] The system consists of a distillation column 1, a discharge pipe 2, a connecting pipe 3, a reversing valve 4, a liquid inlet pipe 5, and a reboiler 6. The L-shaped discharge pipe 2 collects the bottom liquid material, which, via the connecting pipe 3 and reboiler 6, forms a thermal circulation system to heat, vaporize, and reflux the material, maintaining the gas-liquid balance during distillation. The presence of two reboilers 6 ensures uninterrupted production; if one reboiler 6 requires maintenance, the other can continue operating. An opening / closing assembly allows for the sealing and opening of the reboiler 6, facilitating maintenance, cleaning of internal scale, and disassembly of the tube bundle. A quantitative dispensing assembly allows for the quantitative extraction of reagents, enabling the addition of scale inhibitors and buffers into the liquid inlet pipe 5. To achieve precise addition of corrosives, a condenser 10 is installed to cool the gaseous product exiting the top of the distillation column 1, condensing it into a liquid phase. A portion of the condensate returns to the distillation column 1 via the reflux pipe 11, providing reflux liquid for the distillation process and ensuring separation efficiency; the other portion is collected as product. A safety valve assembly ensures safe operation of the system. A micro-differential pressure transmitter 36 monitors the pressure on the upper side of the condenser 10 in real time. When the pressure exceeds the set value, the vent valve 37 automatically opens to release the pressure, preventing damage to the equipment due to overpressure. The distillation column 1 separates the mixture, and the reboiler 6 provides rising steam. The condenser 10 achieves gaseous condensation and reflux. A reversing valve 4 switches the material flow direction and facilitates the flushing and maintenance of the reboiler 6. An opening and closing assembly facilitates cleaning of the reboiler 6, a metering component ensures precise addition of functional liquids, and the safety valve assembly ensures safe operation of the equipment. All these components work together to form a highly efficient, flexible, and safe distillation system.

[0030] The reversing valve 4 includes a sealing frame 12, and a double-pass ball valve 13 is rotatably connected inside the sealing frame 12. The double-pass ball valve 13 is used to change the direction of liquid flow. A rotating handle is fixedly connected to the upper end of the double-pass ball valve 13. The left ends of the two reversing valves 4 are connected through a flushing pipe 14. A water pump 15 is provided in the middle of the flushing pipe 14.

[0031] The double-way ball valve 13 provides a relatively sealed installation space to prevent liquid leakage inside the reversing valve 4. It protects and secures the double-way ball valve 13, ensuring its stable rotation within its enclosure and preventing external impurities from affecting its normal operation. The rotation of the double-way ball valve 13 within the sealing frame 12 changes the liquid flow direction, thus switching the material conveying path. It can guide the liquid to different reboilers 6 to meet different operational needs during production, such as alternating use and maintenance of the reboilers 6. Simultaneously, when one reboiler 6 is in use, the double-way ball valve 13 connects the other reboiler 6 to the water pump 15. The system facilitates internal rinsing. The water pump is connected to the external water pipe, allowing water to be drawn from the outside for rinsing when needed. After the water is drawn, internal circulation begins for rinsing. After rinsing, the internal wastewater can be discharged. A rotating handle allows operators to easily control the rotation angle of the double-way ball valve 13, thereby precisely changing the direction of liquid flow. Automatic switching can also be achieved using mechanical components. The rinsing pipe 14 and water pump 15 enable periodic cleaning of the reboiler 6. The cleaning solution is driven by the water pump 15 to circulate between the rinsing pipe 14 and the equipment, effectively removing dirt from the inside of the equipment, extending the service life of the equipment, and ensuring the efficient and stable operation of the entire distillation unit.

[0032] The opening and closing assembly includes a sealing plate 16, the lower side of which is hinged to the reboiler 6. A rubber ring 17 is fixedly connected to the right end of the sealing plate 16. Rotatable lead screws 18 are provided on the front and rear sides of the reboiler 6. An L-shaped lifting rod 19 is rotatably connected to the outer wall of the lead screw 18. The lifting rod 19 is slidably connected to the reboiler 6. Inclined grooves 20 are provided on the front and rear sides of the sealing plate 16. A connecting pin located in the corresponding inclined groove 20 is fixedly connected to the left side of the lifting rod 19.

[0033] The opening and closing assembly, through the coordinated action of the sealing plate 16, rubber ring 17, lead screw 18, lifting rod 19, tilting groove 20, and connecting pin, enables convenient opening and closing of the reboiler 6. This assembly effectively solves the problems of complex opening and closing methods and inconvenient cleaning and maintenance of existing reboiler 6. The rotation of the lead screw 18 precisely controls the movement of the lifting rod 19, which in turn drives the sealing plate 16 to rotate around the hinge point through the cooperation of the tilting groove 20 and the connecting pin, realizing the rapid opening and closing of the reboiler 6. The rubber ring 17 ensures the sealing of the reboiler 6, improving the working efficiency and safety of the reboiler 6.

[0034] The lower end of the lead screw 18 is fixedly connected to a bevel gear 21, the lower end of the reboiler 6 is fixedly connected to a double-headed motor 22, the output end of the double-headed motor 22 is fixedly connected to a drive shaft 23, and the front and rear sides of the drive shaft 23 are respectively fixedly connected to helical gears 24 that can mesh with the bevel gears 21 on the corresponding side.

[0035] A dual-head motor 22 is set up to transmit power to the lead screw 18, thereby driving the opening and closing assembly to realize the opening and closing function of the reboiler 6 sealing plate 16.

[0036] The quantitative dispensing component includes a dispensing tube 25, which is connected to the liquid inlet tube 5. A sleeve 26 is fixedly connected to the right end of the dispensing tube 25. A lifting tube 27 that can move up and down is provided inside the sleeve 26. A through hole that can communicate with the dispensing tube 25 is opened on one side of the lifting tube 27. A quantitative cylinder 28 is fixedly connected to the upper end of the lifting tube 27. A storage tank 29 is provided to the right of the quantitative cylinder 28. A hinge ball 30 is fixedly connected to the upper end of the quantitative cylinder 28 and the lower end of the storage tank 29, respectively. A hollow telescopic tube 31 is provided between the two hinge balls 30. The left and right sides of the telescopic tube 31 are respectively hinged to the hinge balls 30 on their corresponding sides. The storage tank 29 and the quantitative cylinder 28 can be connected through the telescopic tube 31.

[0037] The dispensing pipe 25 is connected to the inlet pipe 5, allowing the scale inhibitor or corrosion inhibitor in the dispensing pipe 25 to smoothly enter the inlet pipe 5 and then be transported to the reboiler 6 for descaling or corrosion inhibition treatment. A sleeve 26 and a riser pipe 27 are provided; the sleeve 26 provides a track for the riser pipe 27 to move up and down. By controlling the up and down movement of the riser pipe 27, its connection with the dispensing pipe 25 can be adjusted, thereby controlling the dispensing of the agent. A metering cylinder 28 is provided to accurately measure a certain amount of scale inhibitor or corrosion inhibitor, ensuring the accuracy of the dispensing and avoiding affecting the descaling or distillation effect due to inaccurate dispensing. A storage tank 29 stores a large amount of scale inhibitor or corrosion inhibitor, providing a continuous supply of agent to the metering cylinder 28. A hinged ball 30 and a telescopic tube 31 are provided so that when the riser pipe 27 rises and connects with the dispensing pipe 25, the telescopic tube 31 and the hinged ball 30 are no longer connected, thus preventing liquid in the storage tank 29 from flowing into the metering cylinder 28. This ensures that the liquid in the metering cylinder 28 flows into the dispensing pipe 25, achieving quantitative dispensing. The upper end of the metering cylinder 28 is equipped with a one-way valve, which ensures that the liquid in the metering cylinder 28 flows slowly and steadily downwards, while preventing the liquid from flowing out of the one-way valve. After the metering cylinder 28 has finished dispensing, the riser pipe 27 descends and is no longer connected to the dispensing pipe 25, ensuring that the liquid in the metering cylinder 28 flows out, while preventing the liquid in the inlet pipe 5 from flowing into the dispensing pipe 25. At the same time, the telescopic pipe 31 is in a horizontal state, connecting the storage tank 29 and the metering cylinder 28, which can deliver the liquid into the metering cylinder 28, achieving quantitative dispensing and facilitating the next dispensing. Through the coordinated work of each part, the quantitative dispensing component achieves accurate and quantitative dispensing of the scale inhibitor or corrosion inhibitor required by the reboiler 6, solving the problem of the lack of accurate quantitative dispensing device in the prior art, and helping to improve the descaling effect of the reboiler 6 and the overall performance of the distillation unit.

[0038] A bracket located below the lifting pipe 27 is fixedly connected to the upper side of the inlet pipe 5. A deflection wheel 32 is rotatably connected to the upper side of the bracket. The deflection wheel 32 can contact the lower end of the lifting pipe 27. A bevel gear 1 is fixedly connected to the front end of the deflection wheel 32. A drive motor 33 is fixedly connected to the upper side of the inlet pipe 5. A bevel gear 2 that meshes with the bevel gear 1 is fixedly connected to the output end of the drive motor 33.

[0039] The drive motor 33 is configured to provide power for the rotation of the deflection wheel 32, thereby enabling the deployment or stopping of deployment.

[0040] The hinge ball 30 has a movable groove 34, and the left and right sides of the telescopic tube 31 are respectively located in the movable groove 34 on their corresponding sides.

[0041] Ensure that the telescopic tube 31 does not swing arbitrarily.

[0042] A fixing frame is fixedly connected to the lower side of the storage tank 29, and the fixing frame is in contact with the ground.

[0043] The mounting bracket can provide support for the storage tank 29.

[0044] The safety valve assembly includes a differential pressure transmitter 36, which is located on the upper side of the condenser 10. A vent valve 37 is provided on the upper side of the condenser 10 within a radius of less than 500 mm from the differential pressure transmitter 36. The vent valve 37 is connected to the interior of the condenser 10.

[0045] A micro differential pressure transmitter 36 and a vent valve 37 are installed, which work together to form a complete pressure safety protection mechanism. The micro differential pressure transmitter 36 monitors the pressure, and the vent valve 37 handles overpressure situations in a timely manner. This ensures that the condenser 10 operates within a safe pressure range, improving the safety and reliability of the distillation unit. When the pressure inside the condenser 10 exceeds the safety threshold, the vent valve 37 opens, connecting the inside of the condenser 10 to the outside, releasing excess gas, thereby reducing the pressure inside the condenser 10 and preventing safety accidents such as explosions due to excessive pressure. This ensures the safe operation of the distillation column 1 and the entire system. With a radius of less than 500mm, it can achieve simultaneous sensing and pressure prevention, enabling rapid pressure relief.

[0046] A sampling tube 38 is provided on the upper side of the gas outlet pipe 9. An automatic drain valve is provided inside the sampling tube 38. A gas chromatograph 39 is provided on one side of the sampling tube 38.

[0047] By setting up the sampling tube 38, the automatic condensate drain valve and the gas chromatograph 39 in synergy, the gas phase components of the outlet pipe 9 of the distillation column 1 are accurately sampled and analyzed, the concentration of non-condensable gas inside is detected and ensured that it does not exceed the threshold. When the threshold is exceeded, the vacuum pump is controlled in time to reduce the pressure. The vacuum pump is an existing device in the distillation column 1.

[0048] In use, the material enters the distillation column 1 through the feed pipe 8. The material at the bottom of the column enters one of the reboilers 6 through the discharge pipe 2 and the reversing valve 4. After being heated and vaporized, it returns to the distillation column 1. At the same time, a portion of the liquid phase flows out as product. The drive motor 33 rotates according to the set program, and the lifting pipe 27 controls the metering cylinder 28 to add reagents to the liquid inlet pipe 5. The reagents are mixed with the material and enter the reboiler 6. The condenser 10 cools the gaseous product at the top of the column. Part of the condensate is returned, and part is output as product. The micro differential pressure transmitter 36 continuously monitors the pressure of the condenser 10. Once the pressure exceeds the limit, the vent valve 37 opens quickly to release the pressure. At the same time, the gas chromatograph 39 analyzes the sample in the sampling tube 38 in real time. If the concentration of non-condensable gas is abnormal, the vacuum pump is adjusted in time to reduce the pressure. If it is necessary to switch reboilers 6 during operation, turn the handle of the reversing valve 4 to change the material flow direction, so that the standby reboiler 6 can be put into operation. The original reboiler 6 can be flushed. Start the water pump 15 on the flushing pipe 14 to deliver cleaning solution for circulation cleaning. If the reboiler 6 needs deep maintenance, start the double-head motor 22 to open the sealing plate 16, clean it and then close it.

[0049] In this invention, the distillation column 1, the dual-head motor 22 and the drive motor 33, the micro differential pressure transmitter 36 and the gas chromatograph 39 are all existing technologies and will not be described in detail here.

[0050] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane, comprising a distillation column (1), characterized in that, The lower end of the distillation column (1) is fixedly connected to an L-shaped discharge pipe (2). The left side of the distillation column (1) and the left side of the discharge pipe (2) are respectively provided with connecting pipes (3). The left side of the connecting pipe (3) is connected to a reversing valve (4). The front and rear sides of the reversing valve (4) on the lower side are respectively connected to a reboiler (6) via a liquid inlet pipe (5). The other side of the reboiler (6) is connected to the upper reversing valve (4) via a liquid outlet pipe (7). The left side of the reboiler (6) is provided with an opening and closing assembly that can realize its opening and closing. The upper side of the liquid inlet pipe (5) is provided with a quantitative dispensing assembly. The right side of the distillation column (1) is provided with a feed pipe (8). The upper side of the distillation column (1) is provided with a gas outlet pipe (9). The middle part of the gas outlet pipe (9) is provided with a condenser (10). The upper side of the condenser (10) is provided with a safety valve assembly. The lower side of the condenser (10) is provided with a reflux pipe (11). The reflux pipe (11) is connected to the distillation column (1).

2. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 1, characterized in that, The reversing valve (4) includes a sealing frame (12), and a double-pass ball valve (13) is rotatably connected inside the sealing frame (12). The double-pass ball valve (13) is used to change the direction of liquid flow. A rotating handle is fixedly connected to the upper end of the double-pass ball valve (13). The left ends of the two reversing valves (4) are connected through a flushing pipe (14). A water pump (15) is provided in the middle of the flushing pipe (14).

3. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 1, characterized in that, The opening and closing assembly includes a sealing plate (16), the lower side of which is hinged to the reboiler (6), and a rubber ring (17) is fixedly connected to the right end of the sealing plate (16). Rotatable lead screws (18) are provided on the front and rear sides of the reboiler (6). An L-shaped lifting rod (19) is rotatably connected to the outer wall of the lead screw (18). The lifting rod (19) is slidably connected to the reboiler (6). Inclined grooves (20) are provided on the front and rear sides of the sealing plate (16). A connecting pin is fixedly connected to the left side of the lifting rod (19) in the corresponding inclined groove (20).

4. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 3, characterized in that, The lower end of the lead screw (18) is fixedly connected to a bevel gear (21), the lower end of the reboiler (6) is fixedly connected to a double-headed motor (22), the output end of the double-headed motor (22) is fixedly connected to a drive shaft (23), and the front and rear sides of the drive shaft (23) are respectively fixedly connected to helical gears (24) that can mesh with the corresponding bevel gears (21).

5. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 1, characterized in that, The quantitative dispensing component includes a dispensing tube (25), which is connected to the liquid inlet tube (5). A sleeve (26) is fixedly connected to the right end of the dispensing tube (25). A lifting tube (27) that can move up and down is provided inside the sleeve (26). A through hole that can communicate with the dispensing tube (25) is opened on one side of the lifting tube (27). A quantitative cylinder (28) is fixedly connected to the upper end of the lifting tube (27). A storage tank (29) is provided to the right of the quantitative cylinder (28). A hinge ball (30) is fixedly connected to the upper end of the quantitative cylinder (28) and the lower end of the storage tank (29). A hollow telescopic tube (31) is provided between the two hinge balls (30). The left and right sides of the telescopic tube (31) are hinged to the hinge balls (30) on their corresponding sides. The storage tank (29) and the quantitative cylinder (28) can be connected through the telescopic tube (31).

6. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 5, characterized in that, The upper side of the inlet pipe (5) is fixedly connected to a bracket located below the lifting pipe (27). A deflection wheel (32) is rotatably connected to the upper side of the bracket. The deflection wheel (32) can contact the lower end of the lifting pipe (27). A bevel gear is fixedly connected to the front end of the deflection wheel (32). A drive motor (33) is fixedly connected to the upper side of the inlet pipe (5). A bevel gear (2) that meshes with the bevel gear is fixedly connected to the output end of the drive motor (33).

7. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 5, characterized in that, The hinge ball (30) has a movable groove (34), and the left and right sides of the telescopic tube (31) are respectively located in the movable groove (34) on their corresponding sides.

8. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 5, characterized in that, The storage tank (29) is fixedly connected to a frame on its lower side, and the frame is in contact with the ground.

9. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 1, characterized in that, The safety valve assembly includes a differential pressure transmitter (36), which is located on the upper side of the condenser (10). A vent valve (37) is provided on the upper side of the condenser (10) within a radius of less than 500 mm from the differential pressure transmitter (36), and the vent valve (37) is connected to the interior of the condenser (10).

10. The safe purification and distillation apparatus for the preparation of 1,1,1,2-tetrafluoroethane according to claim 1, characterized in that, The upper side of the outlet pipe (9) is provided with a sampling tube (38), an automatic drain valve is provided inside the sampling tube (38), and a gas chromatograph (39) is provided on one side of the sampling tube (38).

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