Production device and production method of phosphorus trifluoride

Abstract

The invention discloses a phosphorus trifluoride production device and method, and belongs to the technical field of phosphorus trifluoride production, the device comprises a reaction part, a pretreatment part and a post-treatment part, the reaction part comprises a first raw material tank, a second raw material tank, a reaction kettle and a collection cold trap, the pretreatment part comprises a primary separation tower and an absorption tower, and the post-treatment part comprises a secondary separation tower and an absorption tower. The post-treatment part comprises an adsorption tower, a light component removal tower and a heavy component removal tower; the production method comprises the following steps: adding raw materials of phosphorus trichloride and hydrogen fluoride into a reaction kettle to generate phosphorus trifluoride and hydrogen chloride, collecting the phosphorus trifluoride and hydrogen chloride in a collecting cold trap, heating the collecting cold trap to vaporize the phosphorus trifluoride and hydrogen chloride, and sequentially entering a primary separation tower, a light component removal tower and a heavy component removal tower for a series of treatment, and finally, high-purity phosphorus trifluoride gas is extracted from the heavy component removal tower to a filling system. According to the method, high-purity phosphorus trifluoride with the purity larger than or equal to 99.999% can be finally produced, and the problem that in the prior art, the purity of phosphorus trifluoride is not enough is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of phosphorus trifluoride production, and particularly to a production device and a production method for high-purity phosphorus trifluoride. Background Art

[0002] In the rapidly developing technological wave today, phosphorus trifluoride, as a crucial inorganic compound, plays an irreplaceable role in multiple key fields. In the electronics industry, especially in the semiconductor manufacturing field, phosphorus trifluoride is converted into a plasma gas under microwave excitation for doping. This process can significantly optimize the performance of semiconductors and greatly promote the iterative upgrade of semiconductor technology. In the battery manufacturing industry, due to its unique chemical properties, phosphorus trifluoride can effectively improve the charge and discharge efficiency and stability of batteries, injecting strong impetus into the research and development of high-performance batteries. In the field of polymer materials, as a reactant, phosphorus trifluoride can participate in reactions to synthesize polymer materials such as fluorinated organic dithiophosphates and terephthalates with excellent anti-corrosion properties, creating considerable economic benefits.

[0003] However, with the rapid progress of technology, the requirements for the purity of phosphorus trifluoride are becoming increasingly stringent. In the existing phosphorus trifluoride production devices and methods, the purity of the produced phosphorus trifluoride is relatively low, making it difficult to meet the continuously increasing quality requirements, which severely restricts the economic benefits and sustainable development of the phosphorus trifluoride preparation process.

[0004] Chinese Patent Application CN 17228643A discloses a method for preparing electronic-grade phosphorus trifluoride. Under the protection of an inert atmosphere, first, phosphorus trichloride is added to a reactor and heated to a temperature controlled at 40°C - 60°C and maintained for 20 - 50 minutes. Then, anhydrous hydrogen fluoride is slowly introduced from the bottom of the reactor to make it fully contact and react to generate phosphorus trifluoride, which is directly condensed and collected. Finally, rectification and purification are carried out to obtain electronic-grade phosphorus trifluoride. However, this preparation method does not disclose the specific operating process of rectification and purification, and the purity of the prepared product is only 99.99%, which cannot meet the requirements of 5N grade, that is, a purity of 99.999%.

[0005] Therefore, there is an urgent need for a production device and a method for preparing high-purity phosphorus trifluoride to solve the above problems. Summary of the Invention

[0006] The present invention provides a production device and a production method for phosphorus trifluoride to solve the defect of insufficient purity in the prior art.

[0007] On the one hand, the present invention provides a production device for phosphorus trifluoride, including: a reaction part, a pretreatment part, and a post-treatment part, wherein, The reaction section includes a first raw material tank, a second raw material tank, a reaction kettle, and a collection cold trap. The output ends of the first raw material tank and the second raw material tank are respectively connected to the input end of the reaction kettle, and the output end of the reaction kettle is connected to the input end of the collection cold trap; The pretreatment section includes a preliminary separation tower and an absorption tower. The preliminary separation tower is connected to the collection cold trap, and the absorption tower is connected to the preliminary separation tower; The post-treatment section includes an adsorption tower, a light component removal tower, and a heavy component removal tower. The inlet end of the adsorption tower is connected to the preliminary separation tower, the outlet end of the adsorption tower is connected to the light component removal tower, the light component removal tower is connected to the heavy component removal tower, and a first output end is provided on the heavy component removal tower; the first output end is connected to a filling system.

[0008] Among them, the setting of the absorption tower also plays a role in absorbing hydrogen chloride impurities in the material, reducing the adsorption load of the adsorption tower and extending its working cycle.

[0009] Optionally, a first input end is provided on the first raw material tank, and the first input end is used to input phosphorus trichloride raw material into the first raw material tank. A second input end is provided on the second raw material tank, and the second input end is used to input hydrogen fluoride raw material into the second raw material tank.

[0010] Optionally, the output end of the first raw material tank is connected to a first feeding pump, the output end of the first feeding pump is connected to the input end of the reaction kettle, the output end of the second raw material tank is connected to a second feeding pump, the output end of the second feeding pump is connected to a hydrogen fluoride vaporizer, the output end of the hydrogen fluoride vaporizer is connected to the input end of the reaction kettle, a reaction kettle condenser and a residual liquid tank are respectively provided on the reaction kettle, and the output end of the reaction kettle condenser is connected to the input end of the collection cold trap.

[0011] Optionally, a preliminary separation tower condenser and a preliminary separation tower reboiler are respectively provided on the top and bottom of the preliminary separation tower. The output end of the preliminary separation tower condenser is connected to the input end of the light component removal tower. The preliminary separation tower reboiler and the bottom of the preliminary separation tower complete a cycle, and the output end of the bottom of the preliminary separation tower is connected to a buffer tank. The output end of the buffer tank is connected to the input end of the absorption tower. A third input end and an absorption tower cooler are respectively provided on the top and bottom of the absorption tower, and the third input end is used to input clear water.

[0012] Optionally, the output end of the adsorption tower is connected to the input end of the light component removal tower, the output end of the light component removal tower is connected to the input end of the heavy component removal tower. A light component removal tower condenser and a light component removal tower reboiler are respectively provided on the top and bottom of the light component removal tower. A heavy component removal tower condenser and a heavy component removal tower reboiler are respectively provided on the top and bottom of the heavy component removal tower. The heavy component removal tower condenser is connected to the first output end.

[0013] On the other hand, the present invention also provides a production method of phosphorus trifluoride using the above production device, and the production method is as follows: S1. After putting a set amount of phosphorus trichloride into the reaction kettle (3), start the reaction kettle (3) to start stirring and heating up to the reaction operation temperature, and control phosphorus trichloride to enter the reaction kettle (3) from the top of the reaction kettle (3) and hydrogen fluoride to enter the reaction kettle (3) from the bottom of the reaction kettle (3) simultaneously for reaction. In a continuous reaction state, reaction gas is generated; S2. Collect and store the reaction gas generated in S1 in a collection cold trap to liquefy it; S3. Raise the temperature of the collection cold trap so that the liquid in the collection cold trap vaporizes into a gas and enters the preliminary fractionation tower at a set flow rate. Among them, the preliminary fractionation product gas drawn from the top of the preliminary fractionation tower enters the de-lighting tower through the preliminary fractionation tower condenser, and the hydrogen chloride gas drawn from the bottom of the preliminary fractionation tower enters the absorption tower after being processed by the preliminary fractionation tower reboiler. Water is added from the third input end of the absorption tower to fuse with the hydrogen chloride gas to form dilute hydrochloric acid; S4. The light components drawn from the top of the de-lighting tower are discharged to an additional waste treatment system through the de-lighting tower condenser, and the de-lighted components drawn from the bottom of the de-lighting tower enter the de-heavy tower after being processed by the de-lighting tower reboiler; S5. The heavy components drawn from the bottom of the de-heavy tower are discharged to the waste treatment system, and the phosphorus trifluoride gas drawn from the top of the de-heavy tower is output to the filling system through the first output end.

[0014] Among them, in step S1, at room temperature, first put one-third of the volume of the reaction kettle with phosphorus trichloride into the reaction kettle, then start the stirring of the reaction kettle and heat up to the reaction operation temperature, and then control the feeding method of phosphorus trichloride to be the upper feeding method and the feeding method of hydrogen fluoride to be the lower feeding method, that is, phosphorus trichloride goes from top to bottom and hydrogen fluoride goes from bottom to top. The two raw materials enter the reaction kettle for reaction at the same time. The reverse flow of the two materials and the sufficient mixing effect of stirring ensure the continuous progress of the reaction and the continuous output of the product gas to the subsequent rectification device.

[0015] Optionally, the operating pressure of the reaction kettle is set to 0.1±0.01 MPa, and the operating temperature is set to 75±5 °C; when the operating pressure of the reaction kettle exceeds 0.2 Mpa and the temperature is higher than 80 °C, the reaction in the reaction kettle is too violent, which may cause dangerous consequences such as gas leakage and even explosion; when the operating pressure of the reaction kettle is lower than 0 Mpa and the temperature is lower than 70 °C, the reaction rate in the reaction kettle is lower than the normal level, which will cause adverse consequences such as extended reaction time and increased by-products.

[0016] Optionally, the pressure of the collection operation of the collection cold trap is set to 0.05±0.02 MPa, and the temperature of the collection operation is set to -100±10°C; the pressure of the discharging operation of the collection cold trap (4) is set to 1.1±0.1 MPa, and the temperature of the discharging operation is set to -42±5°C.

[0017] Among them, when the pressure of the collection operation of the collection cold trap exceeds 0.07 MPa and the pressure of the discharging operation exceeds 1.2 MPa, the collisions between gas molecules will become more frequent, hindering the condensation of gas molecules, affecting the condensation effect, resulting in poor condensation effect, which will not only reduce production efficiency but also affect the purity of the product; in addition, in a high-pressure environment, the cold trap equipment may bear too much load, and long-term operation may lead to increased equipment wear, and even cause equipment failure or damage, resulting in the rupture of the refrigerant pipeline or components, further increasing the risk of equipment damage; when the pressure of the collection operation is lower than 0.03 MPa and the pressure of the discharging operation is lower than 1 MPa, although too low pressure is beneficial to the condensation of gas, it will also cause the liquid in the cold trap to boil or evaporate too fast, which will instead affect the condensation effect. At the same time, too low pressure and temperature will lead to a decrease in the pressure difference between the condenser and the evaporator, too little refrigerant flowing to the evaporator, triggering a low-pressure alarm of the unit, affecting the refrigeration effect and the normal operation of the unit, and will also cause problems such as leakage in the refrigerant pipeline or components due to insufficient pressure, which will not only pollute the environment but also pose a safety hazard to the staff.

[0018] When the temperature of the collection operation of the collection cold trap exceeds -90°C and the temperature of the discharging operation exceeds -37°C, the condensation effect will be affected. That is, too high a cold trap temperature will cause the material gas to not condense effectively in the cold trap, and then the humidity of the dry gas discharged from the exhaust port will be too high, and the drying effect will be poor, which will not only reduce production efficiency but also affect the quality of the final product. When the temperature of the collection operation of the collection cold trap is lower than -110°C and the temperature of the discharging operation is lower than -47°C, although theoretically the lower the cold trap temperature, the stronger the ability to capture materials, too low a temperature may cause the cold trap to frost, affecting the normal operation of the dryer. In addition, too low a temperature may also damage the materials inside the cold trap, shortening the service life of the equipment, and many substances used in the cold trap may cause safety accidents when improperly handled, posing a safety hazard.

[0019] When the operating pressure of the preliminary fractionation tower exceeds 1 MPa, the operating pressure of the absorption tower exceeds 0.06 MPa, the operating pressure of the light component removal tower exceeds 0.8 MPa, and the operating pressure of the heavy component removal tower exceeds 0.7 MPa, accidents such as leakage or explosion will occur, causing casualties and threatening production safety.

[0020] When the operating pressure of the initial fractionation column is lower than 1 MPa, the operating pressure of the absorption column is lower than 0.04 MPa, the operating pressure of the light component removal column is lower than 0.6 MPa, and the operating pressure of the heavy component removal column is lower than 0.5 MPa, it will lead to an increase in the quantity of the top fraction, but a decrease in the concentration of the light components, thus affecting the purity and quality of the product; at the same time, it will also lead to a decrease in the concentration of the light components in the bottom kettle liquid, further affecting the product quality.

[0021] When the operating temperature of the initial fractionation column exceeds -41 °C, the operating temperature of the absorption column exceeds 30 °C, the operating temperature of the light component removal column exceeds -48 °C, and the operating temperature of the heavy component removal column exceeds -56 °C, it will lead to incomplete separation of the product and the product composition deviating from the expectation, thus affecting the product quality and even resulting in unqualified products. Specifically, the concentration of the top distillate may decrease, and the concentration of the volatile components in the residue may increase, causing product quality problems.

[0022] When the operating temperature of the initial fractionation column exceeds -51 °C, the operating temperature of the absorption column exceeds 20 °C, the operating temperature of the light component removal column exceeds -58 °C, and the operating temperature of the heavy component removal column exceeds -66 °C, it will affect the vapor-liquid equilibrium in the column, resulting in a decrease in the content of the light components in the top product, thus reducing the purity of the top product.

[0023] Optionally, the reactor condenser uses R-410A refrigerant at -75 °C as the refrigerant medium, where the R-410A refrigerant is a mixture composed of difluoromethane and pentafluoroethane; a first condenser and a cooling coil are provided on the collection cold trap, and liquid nitrogen is used as the refrigerant medium.

[0024] Optionally, a jacket is also provided on the collection cold trap, and R-410A refrigerant at -10 °C is used as the heating medium.

[0025] Optionally, the initial fractionation column condenser, the light component removal column condenser, and the heavy component removal column condenser all use R-410A refrigerant at -75 °C as the refrigerant medium; the initial fractionation column reboiler, the light component removal column reboiler, and the heavy component removal column reboiler all use dichloromethane at -20 °C as the heating medium; the absorption column cooler uses circulating water as the refrigerant medium.

[0026] The production device and method of phosphorus trifluoride provided by the present invention only use phosphorus trichloride raw materials and hydrogen fluoride raw materials. After adding part of the phosphorus trichloride into the reaction kettle first, the two reaction materials are controlled to enter the reaction kettle simultaneously from top to bottom and from bottom to top for reaction. The reverse flow of the two materials and the sufficient mixing effect of stirring ensure the continuous progress of the reaction. The produced hydrogen chloride gas reacts with water to form dilute hydrochloric acid as a by-product. By using the conventional reaction kettle and distillation device in the prior art and controlling the reaction temperature, reaction pressure, distillation temperature, and distillation pressure, high-purity phosphorus trifluoride with a purity ≥ 99.999% can be finally produced, solving the problem of insufficient purity of phosphorus trifluoride in the prior art and making the large-scale and industrial production of high-purity phosphorus trifluoride a reality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a process flow diagram of the production method of phosphorus trifluoride provided by the present invention; Figure 2 It is a process flow diagram of the production device of phosphorus trifluoride provided by the present invention.

[0029] Reference numerals: 1. First raw material tank; 2. Second raw material tank; 3. Reaction kettle; 4. Collection cold trap; 5. Primary fractionation tower; 6. Absorption tower; 7. Adsorption tower; 8. Light component removal tower; 9. Heavy component removal tower; 10. First output end; 11. First input end; 12. Second input end; 13. First feeding pump; 14. Second feeding pump; 15. Hydrogen fluoride vaporizer; 16. Reaction kettle condenser; 17. Residual liquid tank; 18. Primary fractionation tower condenser; 19. Primary fractionation tower reboiler; 20. Buffer tank; 21. Third input end; 22. Absorption tower cooler; 23. Heavy component removal tower reboiler; 24. Light component removal tower condenser; 25. Light component removal tower reboiler; 26. Heavy component removal tower condenser. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0031] As described above, in the existing phosphorus trifluoride production devices and methods, due to process defects, the purity of the produced phosphorus trifluoride is relatively low, making it difficult to meet the continuously improving quality requirements, which severely restricts the economic benefits and sustainable development of the phosphorus trifluoride preparation process.

[0032] In view of this, the present invention provides a production device and method for phosphorus trifluoride, effectively solving the above problems. The following will specifically describe the present invention in conjunction with Figure 1 - Figure 2 specific descriptions of the present invention.

[0033] Figure 2 is a process flow schematic diagram of a production device for phosphorus trifluoride according to the present invention. As Figure 2 shown, the present invention provides a production device for phosphorus trifluoride, which includes: a reaction part, a pretreatment part, and a post-treatment part. Among them, the reaction part includes a first raw material tank 1, a second raw material tank 2, a reaction kettle 3, and a collection cold trap 4. The output ends of the first raw material tank 1 and the second raw material tank 2 are respectively connected to the input end of the reaction kettle 3, and the output end of the reaction kettle 3 is connected to the input end of the collection cold trap 4. The pretreatment part includes a preliminary separation tower 5 and an absorption tower 6. The preliminary separation tower 5 is connected to the collection cold trap 4, and the absorption tower 6 is connected to the preliminary separation tower 5. The post-treatment part includes an adsorption tower 7, a light component removal tower 8, and a heavy component removal tower 9. The light component removal tower 8 is connected to the preliminary separation tower 5, the adsorption tower 7 is connected to the light component removal tower 8, the light component removal tower 8 is connected to the heavy component removal tower 9, and a first output end 10 is provided on the heavy component removal tower 9, and the first output end 10 is connected to an additional filling system.

[0034] Through the above-mentioned conventional industrial equipment, the present invention enables the raw materials to first enter the reaction kettle 3 for reaction, and its products then sequentially enter the preliminary separation tower 5, the light component removal tower 8, and the heavy component removal tower 9 for a series of reactions, finally producing high-purity phosphorus trifluoride, solving the problem of insufficient purity of phosphorus trifluoride in the prior art, realizing the industrialized and large-scale production of high-purity phosphorus trifluoride, without the need to add new industrial equipment, and reducing the cost of industrial equipment.

[0035] In order to further explain the specific working principle of a production device for phosphorus trifluoride according to the present invention, on the basis of the above embodiment, the present invention also provides another preferred embodiment. As Figure 2 shown, in another preferred embodiment provided by the present invention.

[0036] The reaction part further includes a first input end 11 and a second input end 12. The first input end 11 is connected to the first raw material tank 1 and is used for inputting phosphorus trichloride raw materials. The second input end 12 is connected to the second raw material tank 2 and is used for inputting hydrogen fluoride raw materials.

[0037] Optionally, the output end of the first raw material tank 1 is connected to a first feeding pump 13, and the output end of the first feeding pump 13 is connected to the input end of the reaction kettle 3. During use, the first feeding pump 13 is powered on and driven to extract phosphorus trichloride raw materials from the first raw material tank 1, and then enter the reaction kettle 3. The output end of the second raw material tank 2 is connected to a second feeding pump 14, the output end of the second feeding pump 14 is connected to a hydrogen fluoride vaporizer 15, and the output end of the hydrogen fluoride vaporizer 15 is connected to the input end of the reaction kettle 3. During use, the second feeding pump 14 is powered on and driven to extract hydrogen fluoride raw materials from the second raw material tank 2 and enter the hydrogen fluoride vaporizer 15. The hydrogen fluoride vaporizer 15 is responsible for converting the hydrogen fluoride raw materials from a liquid state to a gaseous state and entering the reaction kettle 3. A reaction kettle condenser 16 and a residue tank 17 are respectively arranged on the reaction kettle 3, and the output end of the reaction kettle condenser 16 is connected to the input end of the collection cold trap 4. The phosphorus trichloride raw materials and gaseous hydrogen fluoride react in the reaction kettle 3 to generate phosphorus trifluoride gas and hydrogen chloride gas. These gases enter the collection cold trap 4 through the pipeline, and the residue generated by the reaction enters the residue tank 17 and can be used as raw materials again after recovery. During this period, the reaction equation of the phosphorus trichloride raw materials and gaseous hydrogen fluoride in the reaction kettle 3 is as follows: PCl3 + 3HF = PF3 + 3HCl.

[0038] Optionally, a primary fractionation tower condenser 18 and a primary fractionation tower reboiler 19 are respectively arranged on the primary fractionation tower 5. The function of the primary fractionation tower condenser 18 is to cool and condense the high-temperature steam rising in the primary fractionation tower 5 into a liquid. Part of the liquid is discharged as the top product, and part is returned to the tower as reflux liquid to improve the separation effect and product purity. At the same time, it can also control the top temperature by adjusting the cooling medium, maintain the gas-liquid balance in the tower, and can recover the heat released during steam condensation to improve the energy utilization efficiency. The primary fractionation tower reboiler 19 is located at the bottom of the primary fractionation tower 5, and its main function is to heat the bottom liquid of the tower to partially vaporize the liquid. The generated steam provides the upward gas flow for mass transfer and heat transfer in the tower, and fully contacts the descending liquid to achieve mass exchange and separation. The output end of the primary fractionation tower condenser 18 is connected to the input end of the light component removal tower 8, the output end of the bottom of the primary fractionation tower 5 is connected to a buffer tank 20, and the output end of the buffer tank 20 is connected to the input end of the absorption tower 6. The absorption tower 6 is mainly used for gas purification, can remove harmful gases and dust particles, and reduce pollutant emissions; it can also be used for gas separation and recovery, separating mixtures by using the solubility difference of gases in the absorbent and recovering useful gases. A third input end 21 and an absorption tower cooler 22 are respectively arranged on the top and bottom of the absorption tower 6, and the third input end 21 is used to input clear water.

[0039] Optionally, the output end of the adsorption tower 7 is connected to the input end of the light component removal tower 8, and the output end of the adsorption tower 7 is connected to the input end of the heavy component removal tower 9. A light component removal tower condenser 24 and a light component removal tower reboiler 25 are respectively arranged at the top and the bottom of the light component removal tower 8. The function of the light component removal tower condenser 24 is to cool the high-temperature steam containing light components rising in the light component removal tower 8, so that the light components in the steam condense into liquid. Part of the liquid is output as the top product, and the other part is returned to the light component removal tower 8 as reflux liquid to control the top temperature, maintain the gas-liquid balance in the tower, improve the separation effect of the light components from other components, and ensure the purity of the top product. The light component removal tower reboiler 25 is located at the bottom of the light component removal tower (i.e., the bottom of the tower). Its main function is to heat the bottom liquid, so that part of the light components in the liquid are vaporized. The generated steam provides the upward gas flow for mass transfer and heat transfer in the tower, and fully contacts with the descending liquid to realize the further separation of the light components. At the same time, by controlling the heating amount, the gas-liquid balance state in the tower is maintained, ensuring the stable operation of the light component removal tower 8 and enabling the light components to be better separated from the top of the tower.

[0040] Similarly, a heavy component removal tower condenser 26 and a heavy component removal tower reboiler 23 are respectively arranged at the top and the bottom of the heavy component removal tower 9. The function of the heavy component removal tower condenser 26 is to cool the high-temperature steam containing light components and a small amount of heavy components rising in the heavy component removal tower 9, so that the light components and part of the condensable heavy components in it condense into liquid. Part of the liquid is output as the top product to obtain the light component product, and the other part is returned to the heavy component removal tower 9 as reflux liquid for controlling the top temperature, maintaining the gas-liquid balance in the tower, improving the separation effect of the light components from the heavy components, and ensuring the purity of the top product. The heavy component removal tower reboiler 23 is located at the bottom of the heavy component removal tower 9. Its main function is to heat the bottom liquid, so that the light components in the liquid are further vaporized. The generated steam provides the upward gas flow for mass transfer and heat transfer in the tower, and fully contacts with the descending liquid to realize the further separation of the light components from the heavy components. At the same time, by controlling the heating amount, the gas-liquid balance state in the tower is maintained, ensuring the stable operation of the heavy component removal tower 9, enabling the heavy components to stay better at the bottom of the tower, and the light components to be separated from the top of the tower. Finally, the heavy component removal tower 9 condenser is connected to the first output end. The first output end 10 is connected to an additional filling system for filling the produced phosphorus trifluoride product.

[0041] It should be noted that for the above-mentioned phosphorus trifluoride production device, the transfer of materials depends on the pipelines connecting between each component, the valves on the pipelines, the refrigerant, heat medium, etc. required by each component during operation. Since they all belong to the commonly used existing technologies in this field, they are not pointed out in this embodiment, and their technical principles are not elaborated here either.

[0042] Therefore, through the above-mentioned phosphorus trifluoride production device, the present invention can finally produce high-purity phosphorus trifluoride with a purity ≥ 99.999%, solving the problems of many by-products and insufficient purity of phosphorus trifluoride in the prior art.

[0043] Based on the same general inventive concept and the above production device for phosphorus trifluoride, the present invention also provides a production method for phosphorus trifluoride, as Figure 1 shown, which comprises the following steps: S1. Using the first feeding pump 13, a predetermined amount of phosphorus trichloride raw material is extracted from the first raw material tank 1 and added into the reaction kettle 3. The reaction kettle 3 is started to stir and heated to the reaction operation temperature. Then, a predetermined amount of phosphorus trichloride raw material is continuously extracted from the first raw material tank 1 and re-entered into the reaction kettle 3 from the top of the reaction kettle 3. At the same time, using the second feeding pump 14, a predetermined amount of hydrogen fluoride raw material is extracted from the second raw material tank 2 and added into the hydrogen fluoride vaporizer 15. The hydrogen fluoride raw material is processed by the hydrogen fluoride vaporizer 15 and changed from a liquid to a gas, and simultaneously enters the reaction kettle 3 from the bottom of the reaction kettle 3 to react with the phosphorus trichloride raw material to generate reaction gas. Among them, the operating pressure of the reaction kettle 3 is set to 0.1 ± 0.1 MPa, and the operating temperature is set to 75 ± 5 °C.

[0044] S2. The reaction gas generated in S1 is collected and stored in the collection cold trap 4 to be liquefied. At the same time, the residual liquid generated in the reaction in S1 is collected in the residual liquid tank 17, output and used as a raw material continuously. Among them, the pressure of the collection operation of the collection cold trap 4 is set to 0.05 ± 0.02 MPa, and the operating temperature is set to -100 ± 10 °C.

[0045] S3. The temperature of the collection cold trap 4 is raised so that the liquid in the collection cold trap 4 is vaporized into a gas and enters the preliminary separation tower 5 in a predetermined amount. Among them, the preliminary separation product gas drawn from the top of the preliminary separation tower 5 enters the preliminary separation tower condenser 18, is condensed into a product liquid and then enters the light component removal tower 8. The hydrogen chloride gas drawn from the bottom of the preliminary separation tower 5 is processed by the preliminary separation tower reboiler 19 and enters the absorption tower 6. The absorption tower 6 adds clear water and hydrogen chloride gas to be fused from the third input end 21 to form dilute hydrochloric acid. In this step, the pressure of the discharging operation of the collection cold trap 4 is set to 1.1 ± 0.1 MPa, and the operating temperature is set to -42 ± 5 °C; the operating pressure of the preliminary separation tower 5 is set to 0.9 ± 0.1 MPa, and the operating temperature is set to -46 ± 5 °C; the operating pressure of the absorption tower 6 is set to 0.05 ± 0.01 MPa, and the operating temperature is set to 25 ± 5 °C.

[0046] S4. The liquid entering the light component removal tower 8 is decomposed into light components and light component-removed components. The light components are collected by the light component removal tower 8 and output to an additional three-waste treatment system through its waste discharge port. The light component-removed components enter the heavy component removal tower 9. Among them, the operating pressure of the light component removal tower 8 is set to 0.7 ± 0.1 MPa, and the operating temperature is set to -53 ± 5 °C.

[0047] S5. The output from the heavy component removal column 9 is the heavy components and phosphorus trifluoride gas. The heavy components are withdrawn from the bottom of the heavy component removal column 9 and output to an additional waste treatment system through its waste discharge port. The phosphorus trifluoride gas withdrawn from the top of the heavy component removal column 9 is output to the filling system through the first output terminal 10. In this step, the operating pressure of the heavy component removal column 9 is set to 0.6 ± 0.1 MPa, and the operating temperature is set to -61 ± 5 °C.

[0048] The waste gas output from the waste discharge port is the non-condensable gas of the collection cold trap 4, the light components and heavy components withdrawn from the light component removal column 8 and the heavy component removal column 9, with a composition of 10% nitrogen and 90% phosphorus trifluoride. It is sprayed and absorbed with 10% sodium hydroxide solution, and the nitrogen is discharged at high altitude. The reaction process is expressed by the following chemical equation: PH3 + 4NaOH = 3NaF + NaPO2 + 2H2O.

[0049] The waste liquid is the absorption liquid and is sent out for off-site treatment.

[0050] Next, in combination with the following embodiments, the production process of phosphorus trifluoride of the present invention will be described in detail.

[0051] First, at room temperature, 472 kg of phosphorus trichloride (about 100 L) is charged into a 300 L reaction kettle, and then the stirring is started and the temperature is raised to the reaction operating temperature. Then, 45.7 kg / h of phosphorus trichloride (upper feed, the material goes from top to bottom) and 20.0 kg / h of hydrogen fluoride (lower feed, the material goes from bottom to top) are simultaneously fed into the reactor for reaction. The reverse flow of the two materials plus the sufficient mixing effect of stirring ensure the continuous progress of the reaction, and the continuous output of the product gas to the subsequent rectification device.

[0052]

[0053] Table 1 Pressure and temperature setting table for Examples 1 - 5.

[0054] In Examples 1 - 5, the reaction kettle condenser 16 uses R-410A refrigerant at -75 °C as the refrigerant; a first condenser and a cooling coil are provided on the collection cold trap 4, and liquid nitrogen is used as the refrigerant. A jacket is also provided on the collection cold trap 4, and R-410A refrigerant at -10 °C is used as the heat medium. The primary fractionation column condenser 18, the light component removal column condenser 24, and the heavy component removal column condenser 26 all use R-410A refrigerant at -75 °C as the refrigerant; the primary fractionation column reboiler 19, the light component removal column reboiler 25, and the heavy component removal column reboiler 23 all use dichloromethane at -20 °C as the heat medium; the absorption tower cooler uses circulating water as the refrigerant.

[0055] The phosphorus trifluoride produced in Examples 1 - 5 all achieves a purity of ≥99.999%.

[0056] By using existing conventional production equipment and through repeated experimental studies, the inventors of the present invention have determined the operating pressure and operating temperature suitable for industrial production. By presetting the feeding amount, discharging amount, operating temperature, and operating pressure, stable industrial production of phosphorus trifluoride can be achieved.

[0057]

[0058] Table 2 Pressure and Temperature Setting Table for Comparative Examples 1 - 5.

[0059]

[0060] Table 3 Pressure and Temperature Setting Table for Comparative Examples 6 - 10.

[0061]

[0062] Table 4 Pressure and Temperature Setting Table for Comparative Examples 11 - 14.

[0063] Tables 2 to 4 show the data records when the operating pressure and operating temperature in each step of Comparative Examples 1 to 14 change. Among them, In Comparative Example 1, the operating pressure of the reaction kettle was increased compared to Example 1 (the operating temperature of the reaction kettle also increased accordingly); In Comparative Example 2, the operating pressure of the reaction kettle was decreased compared to Example 2 (the operating temperature of the reaction kettle also decreased accordingly); In Comparative Example 3, the collection operating pressure of the collection cold trap was increased compared to Example 3 (the collection operating temperature of the collection cold trap also increased accordingly); In Comparative Example 4, the collection operating pressure of the collection cold trap was decreased compared to Example 4 (the collection operating temperature of the collection cold trap also decreased accordingly); In Comparative Example 5, the discharging operating pressure of the collection cold trap was increased compared to Example 5 (the discharging operating temperature of the collection cold trap also increased accordingly); In Comparative Example 6, the discharging operating pressure of the collection cold trap was decreased compared to Example 1 (the discharging operating temperature of the collection cold trap also decreased accordingly); In Comparative Example 7, the operating pressure of the preliminary fractionation tower was increased compared to Example 2 (the operating temperature of the preliminary fractionation tower also increased accordingly); In Comparative Example 8, the operating pressure of the preliminary fractionation tower was decreased compared to Example 3 (the operating temperature of the preliminary fractionation tower also decreased accordingly); In Comparative Example 9, the operating pressure of the absorption tower was increased compared to Example 4 (the operating temperature of the absorption tower also increased accordingly); In Comparative Example 10, the operating pressure of the absorption tower was decreased compared to Example 5 (the operating temperature of the absorption tower also decreased accordingly); In Comparative Example 11, the operating pressure of the light - ends removal tower was increased compared to Example 1 (the operating temperature of the light - ends removal tower also increased accordingly); Comparative Example 12 reduced the operating pressure of the light removal column compared to Example 2 (and the operating temperature of the light removal column also decreased accordingly). Comparative Example 13 increased the operating pressure of the heavy removal column compared to Example 3 (and the operating temperature of the heavy removal column also increased accordingly). Comparative Example 14 reduced the operating temperature of the heavy removal column compared to Example 4 (and the operating temperature of the heavy removal column also decreased accordingly).

[0064]

[0065] Table 5 Product purity data of Comparative Examples 1-14.

[0066] Table 5 shows the initial data of Comparative Examples 1 to 14. It can be seen from Table 5 that when the operating pressure and operating temperature in each step change, the purity of the final product will also be affected, and it is far lower than the purity of ≥99.999% in Examples 1 to 5.

[0067] Thus, through the method described in the above embodiments of the present invention, the purity of phosphorus trifluoride production is improved, and the production scale is 200 t / year with an annual operating time of 7200 hours, meeting the increasingly strict requirements for the purity of phosphorus trifluoride nowadays and ensuring the economic benefits and sustainable development of its preparation process.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A phosphorus trifluoride production device, characterized in that: include: Reaction part, pre-treatment part and post-treatment part, wherein, The reaction part comprises a first raw material tank (1), a second raw material tank (2), a reaction kettle (3) and a collecting cold trap (4), wherein the output ends of the first raw material tank (1) and the second raw material tank (2) are respectively connected to the input end of the reaction kettle (3), and the output end of the reaction kettle (3) is connected to the input end of the collecting cold trap (4); The pre-treatment part comprises a primary separation tower (5) and an absorption tower (6), wherein the primary separation tower (5) is connected to the collection cold trap (4), and the absorption tower (6) is connected to the primary separation tower (5); The post-processing part comprises an adsorption tower (7), a light-removal tower (8) and a heavy-removal tower (9); the inlet end of the adsorption tower (7) is connected to the primary separation tower (5); the outlet end of the adsorption tower (7) is connected to the light-removal tower (8); the light-removal tower (8) is connected to the heavy-removal tower (9); a first output end (10) is provided on the heavy-removal tower (9); and the first output end (10) is connected to a filling system.

2. The phosphorus trifluoride production device according to claim 1, characterized in that: The first raw material tank (1) is provided with a first input end (11), and the first input end (11) is used to input phosphorus trichloride raw material into the first raw material tank (1). The second raw material tank (2) is provided with a second input end (12), and the second input end (12) is used to input hydrogen fluoride raw material into the second raw material tank (2).

3. The phosphorus trifluoride production device according to claim 1, characterized in that: The output end of the first raw material tank (1) is connected to a first feeding pump (13), and the output end of the first feeding pump (13) is connected to the input end of the reactor (3). The output end of the second raw material tank (2) is connected to a second feeding pump (14), and the output end of the second feeding pump (14) is connected to a hydrogen fluoride vaporizer (15), and the output end of the hydrogen fluoride vaporizer (15) is connected to the input end of the reactor (3). The reactor (3) is provided with a reactor condenser (16) and a residual liquid tank (17), respectively, and the output end of the reactor condenser (16) is connected to the input end of the collecting cold trap (4).

4. The phosphorus trifluoride production device according to claim 1, characterized in that: A primary tower condenser (18) and a primary tower reboiler (19) are respectively arranged on the top and bottom of the primary tower (5); the output end of the primary tower condenser (18) is connected to the input end of the light removal tower (8); the primary tower reboiler (19) and the bottom of the primary tower (5) complete the circulation; and a buffer tank (20) is connected to the output end of the bottom of the primary tower (5); the output end of the buffer tank (20) is connected to the input end of the absorption tower (6); a third input end (21) and an absorption tower cooler (22) are respectively arranged on the top and bottom of the absorption tower (6); the third input end (21) is used to input clean water.

5. The phosphorus trifluoride production device according to claim 1, characterized in that: The output end of the adsorption tower (7) is connected to the input end of the light removal tower (8), and the output end of the light removal tower (8) is connected to the input end of the heavy removal tower (9). The top and bottom of the light removal tower (8) are respectively provided with a light removal tower condenser (24) and a light removal tower reboiler (25), and the top and bottom of the heavy removal tower (9) are respectively provided with a heavy removal tower condenser (26) and a heavy removal tower reboiler (23), and the heavy removal tower condenser (26) is connected to the first output end (10).

6. A method for producing phosphorus trifluoride using the production device according to any one of claims 1 to 5, characterized in that: The production method comprises: S1. After a set amount of phosphorus trichloride is added to the reactor (3), the reactor (3) is started to stir and heated to a reaction operating temperature, and phosphorus trichloride is controlled to enter the reactor (3) from the top and hydrogen fluoride from the bottom of the reactor (3) simultaneously to react, and a reaction gas is generated in a continuous reaction state; S2, collecting and storing the reaction gas generated in S1 in a collection cold trap (4) to liquefy it; S3, raising the temperature of the collecting cold trap (4) so ​​that the liquid in the collecting cold trap (4) is vaporized into gas and enters the primary separation tower (5) at a set flow rate, wherein the primary separation product gas extracted from the top of the primary separation tower (5) enters the lightness removal tower (8), and the hydrogen chloride gas extracted from the bottom of the primary separation tower (5) enters the absorption tower (6); S4, the light components extracted from the top of the light removal tower (8) are discharged to an additionally loaded three-waste treatment system, and the light components extracted from the bottom of the light removal tower (8) are entered into the heavy removal tower (9); and S5, the heavy components extracted from the bottom of the de-weighting tower (9) are discharged to the three-waste treatment system, and the phosphorus trifluoride gas extracted from the top of the de-weighting tower (9) is output to the filling system via the first output port (10).

7. The method for producing phosphorus trifluoride according to claim 6, characterized in that: The operating pressure of the reactor (3) is set to 0.1±0.01 MPa, and the operating temperature is set to 75±5°C; The collection operation pressure of the collection cold trap (4) is set to 0.05±0.02MPa, and the collection operation temperature is set to -100±10°C; The discharge operation pressure of the collecting cold trap (4) is set to 1.1±0.1MPa, and the discharge operation temperature is set to -42±5°C; The operating pressure of the primary separation tower (5) is set to 0.9±0.1 MPa, and the operating temperature is set to -46±5°C; The operating pressure of the absorption tower (6) is set to 0.05±0.01MPa, and the operating temperature is set to 25±5°C; The operating pressure of the light removal tower (8) is set to 0.7±0.1 MPa, and the operating temperature is set to -53±5°C; The operating pressure of the deweighting tower (9) is set to 0.6±0.1 MPa, and the operating temperature is set to -61±5°C.

8. The method for producing phosphorus trifluoride according to claim 6, characterized in that: The reactor condenser (16) uses R-410A refrigerant at -75°C as a refrigerant; The collecting cold trap (4) is provided with a first condenser and a cooling coil, and liquid nitrogen is used as a refrigerant.

9. The method for producing phosphorus trifluoride according to claim 8, characterized in that: The collecting cold trap (4) is also provided with a jacket, and uses R410A at -10°C as a heat medium.

10. The method for producing phosphorus trifluoride according to claim 6, characterized in that: The primary separation tower condenser (18), the lightness removal tower condenser (24) and the heavyness removal tower condenser (26) all use R410A at -75°C as a refrigerant; The primary tower reboiler (19), the light-removal tower reboiler (25) and the heavy-removal tower reboiler (23) all use dichloromethane at -20°C as a heat medium; The absorption tower cooler (22) uses circulating water as a refrigerant.

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