Preparation method of phosphorus trifluoride

Abstract

The invention discloses a preparation method of phosphorus trifluoride. The preparation method comprises the following steps: S1, respectively adding phosphorus trichloride and anhydrous hydrogen fluoride into a uniform-temperature material changing structure of a reaction kettle; s2, condensing the crude phosphorus trifluoride gas, introducing the condensed crude phosphorus trifluoride gas into a first storage tank for storage, heating liquid in the first storage tank, and pumping the heated liquid into a flash evaporator for flash evaporation; s3, introducing the gas subjected to flash evaporation into a first rectifying tower for rectification, and introducing a product into an intermediate first product storage tank; s4, rectifying the material in the middle first product storage tank, condensing the rectified gas, and introducing the condensed gas into the first product storage tank for storage; s5, gasifying the finished product in the first product storage tank, enabling the gasified finished product to enter a gas-liquid separation tank for separation, discharging separated gas from the top, and sequentially introducing the separated gas into three phosphorus trifluoride purification devices for purification; s6, the purified gas is introduced into a filter to be filtered, the filtered gas enters a filling system to be filled after the pressure of the filtered gas is stabilized, and the stability of the product and the safety of equipment are guaranteed.

Description

Technical Field

[0001] The present invention relates to a production technology of phosphorus trifluoride, in particular to a preparation method of phosphorus trifluoride. Background Art

[0002] Phosphorus trifluoride can be used as a fluorinating agent, which can carry out ion transfer and is applied in fields such as the electronics industry, battery manufacturing, polymer materials, and catalysts; in semiconductor manufacturing, phosphorus trifluoride becomes a plasma gas under microwave action for doping, which can significantly improve the performance of semiconductors; in the field of polymer materials, phosphorus trifluoride can be used as a reactant to synthesize polymer materials such as fluorinated organic dithiophosphates and terephthalates with good anti-corrosion properties. In the preparation of phosphorus trifluoride, phosphorus trichloride and anhydrous hydrogen fluoride are mostly used as raw materials for displacement reaction to produce phosphorus trifluoride and hydrogen chloride, and its chemical reaction equation is: PCI3 + 3HF → 3HCI + PF3.

[0003] A large amount of heat is generated in the displacement reaction. If phosphorus trichloride and anhydrous hydrogen fluoride are all introduced into the reaction kettle at one time, the heat energy generated during the instantaneous reaction is likely to cause the temperature to rise rapidly, making it difficult to control the reaction conditions. Therefore, the prior art uses a microchannel reactor to prepare phosphorus trifluoride, and a special reactor is used to achieve the mixing of the two materials. Although it can achieve the purpose of uniform mixing and rapid heat exchange, it is necessary to purchase a special reactor, and one reactor can only be used for one purpose, increasing the cost input of the enterprise.

[0004] Therefore, this case aims to provide a preparation method of phosphorus trifluoride, which can directly achieve the effect of a microchannel reactor in a conventional reaction tank, ensuring the stability of the product and the safety of the equipment. Summary of the Invention

[0005] The present invention provides a preparation method of phosphorus trifluoride, which can effectively solve the above problems.

[0006] The present invention is implemented as follows: A preparation method of phosphorus trifluoride, comprising: S1: Add phosphorus trichloride and anhydrous hydrogen fluoride into the temperature-uniformizing and material-changing structure of the reaction kettle respectively. Keep the reaction temperature of the reaction kettle at 40 to 50 °C. The crude phosphorus trifluoride gas after reaction is discharged along the discharge port of the reaction kettle. A feeding seat is arranged on the reaction kettle. The temperature-uniformizing and material-changing structure is locked on a sliding cylinder, and the sliding cylinder is slidably connected to the inner wall of the reaction kettle. The temperature-uniformizing and material-changing structure includes a uniformly-distributed plate movably installed in the reaction kettle. The uniformly-distributed plate communicates with the feeding seat. A multi-channel reaction structure is connected below the uniformly-distributed plate. A multi-stage heat exchange structure is arranged inside the multi-channel reaction structure. A number of heat exchange guide heads are opened on the reaction kettle. After the sliding cylinder is installed in the reaction kettle, it rotates to make the multi-channel reaction structure dock with the heat exchange guide heads. The phosphorus trichloride and anhydrous hydrogen fluoride are mixed through the feeding seat, the uniformly-distributed plate and the multi-channel reaction structure and then flow into the reaction kettle. S2: Condense the crude phosphorus trifluoride gas and store it in the first storage tank. Then heat the liquid in the first storage tank and pump it into the flash evaporator for flashing. S3: Feed the gas after flashing into the first distillation column for distillation. Return the hydrogen fluoride at the bottom of the distillation in the first distillation column to the phosphorus trifluoride synthesis process. Condense the top products of phosphorus trifluoride and hydrogen chloride after distillation and feed them into the intermediate first product storage tank. S4: Pump the materials in the intermediate first product storage tank into the second distillation column for distillation. Condense the top gas of the distillation in the second distillation column. Part of the condensed product is refluxed to the second distillation column, and part of it is sent to the first product storage tank for storage. S5: Pump the finished product in the first product storage tank into the vaporizer for vaporization. The vaporized gas enters the gas-liquid separation tank for separation. The separated liquid is refluxed to the vaporizer, and the separated gas is discharged from the top and sequentially fed into three phosphorus trifluoride purification devices for purification. S6: Feed the purified gas into the filter for filtration. The filtered gas enters the second product storage tank. The gas in the second product storage tank is pressurized by a compressor and enters the buffer tank for pressure stabilization storage, and then enters the filling system for filling after pressure stabilization.

[0007] As a further improvement, the feeding seat includes a feeding plate arranged inside the reaction kettle. A number of Y-shaped joints penetrating the reaction kettle are arranged on the top of the feeding plate. The Y-shaped joints are respectively connected to the input ends of phosphorus trichloride and anhydrous hydrogen fluoride.

[0008] As a further improvement, a barrier pile is arranged inside the reaction kettle. A number of universal guide wheels are arranged on the outer side of the sliding cylinder. A convection column is arranged at the bottom of the outer side surface of the sliding cylinder. The convection column docks with the heat exchange guide heads after the sliding cylinder rotates. The bottom of the sliding cylinder fits on the barrier pile.

[0009] As a further improvement, the multi-channel reaction structure includes a number of multi-flow tubes connected to a uniform distribution disk. The lengths of the multi-flow tubes gradually increase from left to right. The multi-flow tubes are docked with an outer ring tube. The outer ring tubes are closely attached to the inner side of the sliding cylinder and are spaced apart from each other. A downcomer is provided on the side of the multi-flow tubes away from the uniform distribution disk.

[0010] As a further improvement, the downcomer includes a downcomer head connected to the outer ring tube. A multi-fold tube is connected below the downcomer head, and a distribution head is connected to the lower end of the multi-fold tube.

[0011] As a further improvement, adjacent multi-fold tubes are connected by a stabilizing band, and the stabilizing band on the outermost multi-fold tube is connected to the inner wall of the sliding cylinder.

[0012] As a further improvement, a corrugated layer is provided on the inner side of the outer ring tube.

[0013] As a further improvement, the multi-stage heat exchange structure includes a horizontal accommodation part closely attached to the lower end of the uniform distribution disk. The lower end of the horizontal accommodation part is respectively connected to a horizontal embedded part and a vertical embedded part. The horizontal embedded parts communicate with each other through a bending part. The horizontal embedded parts are embedded in the gaps between the outer ring tubes. The vertical embedded part is embedded on the outside of the downcomer. The lowermost horizontal embedded part and the vertical embedded part are connected into a bottom accommodation part.

[0014] As a further improvement, a heat flow guiding inlet head is provided on the horizontal accommodation part, and a heat flow guiding outlet head is provided on the bottom accommodation part. Both the heat flow guiding inlet head and the heat flow guiding outlet head are connected to a heat exchange guiding head.

[0015] The beneficial effects of the present invention are as follows: In the existing preparation of phosphorus trifluoride, a micro-channel reactor is mostly used to delay the extremely fast heat exchange reaction process, so as to ensure the stability of the reaction products and the thoroughness of the reaction. Although the experimental purpose can be achieved, a special reactor is required. Enterprises need to purchase a variety of reactors for different reactions. Therefore, in the present invention, through the slidably arranged sliding cylinder, the uniform temperature feeding structure is arranged in the sliding cylinder, and then the position of the sliding cylinder is adjusted, so that the reaction of phosphorus trifluoride can be directly completed in the uniform temperature feeding structure, and the product is then discharged to the purification stage through the reaction kettle, so that it can be directly completed in the reaction kettle through a replaceable component. When preparing other chemical products and there is no need to accurately control the reaction conditions, the uniform temperature feeding structure can be directly removed, making the reaction kettle become an ordinary reaction kettle, so as to directly achieve the effect of multiple uses of one device, and at the same time have the functions of normal mixing reaction and micro-channel reaction.

[0016] During the installation of the sliding cylinder, it needs to reach an accurate position. Otherwise, it is difficult to achieve the effects of inflow and outflow. Therefore, universal guide wheels are arranged on the outer side of the sliding cylinder of the present invention, which can realize the rotation of the sliding cylinder in the circumferential direction, so that the convection column of the sliding cylinder can form a stable connection with the heat exchange guide head.

[0017] In order to achieve the effect of a microchannel reactor in the temperature-equalizing charging structure, the present invention first arranges a multi-channel reaction structure below the uniform distribution plate, so as to realize the long-path reaction of a single channel. It can not only pour the raw materials through multiple channels, but also achieve a relatively uniform mixing effect in each channel, so as to achieve a uniform and stable reaction effect.

[0018] Since there are many channels in the multi-channel reaction structure, realizing the flow of multiple channels and the need for relatively long flow channels between multiple channels at the same time are pain points in the design. Therefore, the multi-channel reaction structure of the present invention adopts multi-flow tubes with different lengths, and the outer ring tubes are arranged at different heights, so as to realize the dispersion and extension of the flow channels, so as to achieve the effects of flow splitting and long diameter.

[0019] For the fluid after passing through the extended path of the outer ring tube, if it is directly discharged into the reaction kettle at this time, the relative distance is still not long enough. Therefore, the present invention arranges a downcomer at the lower end of the outer ring tube, and sets the main path of the downcomer as a multi-fold tube. The pipeline structure with multiple bends can make the fluid form a turbulent flow phenomenon when flowing, so as to improve the mixing effect.

[0020] Although the design of multiple multi-fold tubes improves the mixing effect, in fact, multiple thin and parallel multi-fold tubes will reduce the overall stability and will be relatively unstable when the fluid passes through. Therefore, the multi-fold tubes in this embodiment are connected by a stabilizing belt, and the multi-fold tubes are also connected to the sliding cylinder, so as to form a stable multi-section structure.

[0021] Although the multi-channel reaction structure can achieve the effects of long diameter and sufficient reaction, due to the relatively long structural path and variable route path of the multi-channel reaction structure, it is not easy to exchange heat, so more heat will accumulate in the reaction kettle. Therefore, the present invention sets a multi-stage heat exchange structure on the basis of the multi-channel reaction structure, which is embedded inside the multi-channel reaction structure and is in full contact with the multi-channel reaction structure, so as to achieve the effect of rapid heat exchange in multiple parts. Brief Description of the Drawings

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0023] Figure 1 is a schematic flow diagram of the present invention.

[0024] Figure 2 is a schematic internal structure diagram of the reactor of the present invention.

[0025] Figure 3 is a schematic structural diagram of the temperature equalizing and charging structure of the present invention.

[0026] Figure 4 is a schematic structural diagram of the multi-stage heat exchange structure of the present invention.

[0027] Figure 5 is a schematic structural diagram of the multi-channel reaction structure of the present invention.

[0028] Figure 6 is a schematic structural diagram of the lower flush pipe of the present invention.

[0029] Figure 7 is a front view structural schematic diagram of the phosphorus trifluoride purification equipment of the present invention.

[0030] Figure 8 is a top view structural schematic diagram of the phosphorus trifluoride purification equipment of the present invention.

[0031] Figure 9 is a schematic internal structure diagram of the phosphorus trifluoride purification equipment of the present invention.

[0032] Figure 10 is a schematic structural diagram of the first molecular sieve adsorption cylinder of the present invention.

[0033] Figure 11 is a schematic structural diagram of the pressure regulating disc of the present invention.

[0034] Figure 12 is a schematic structural diagram of the internal barrier structure of the present invention.

[0035] Figure 13 is a schematic structural diagram of the installation platform of the present invention.

[0036] Figure 14 is a schematic structural diagram of the top bone assembly of the present invention.

[0037] In the figure: Reactor 1, discharge port 101, feeding seat 102, feeding plate 1021, Y-type joint 1022, barrier pile 103, uniform temperature material exchange structure 2, uniform distribution plate 201, multi-channel reaction structure 202, multi-flow column 2021, outer ring tube 2022, lower punch 2023, lower punch 20231, multi-fold tube 20232, layout head 20233, stabilizing belt 20234, fold layer 20235, multi-stage heat exchange structure 203, horizontal accommodating part 2031, heat flow guide inlet 20311, heat flow guide outlet 20312, horizontal embedded part 2032, vertical embedded part 2033, bending part 2034, bottom accommodating part 2035, heat exchange guide head 204, sliding cylinder 3, universal guide wheel 301, convection column 302, adsorption tower body 1 0, guide rail 11, inner groove 12, bearing pocket seat 13, upper cover 20, air outlet end 30, double-position sliding molecular sieve structure 40, first molecular sieve adsorption cylinder 41, material placement frame 411, matching rib groove 412, limit piece 413, sealing gasket 4131, locking nail 4132, second molecular sieve adsorption cylinder 42, pressure variable diameter adjustment structure 50, elastic adjustment component 51, first limit spring 511, second limit spring 512, mounting platform 513, C-type ferrule 5131, positioning pin 5132, pressure adjustment disk 52, hole 521, pressure movable disk 522, axial flow channel 523, return flow channel 524, inner barrier structure 53, touch part 531, barrier part 532, top bone component 54, extension rod seat 541, separation rod 542. DETAILED DESCRIPTION

[0038] In order to make the embodiments of the present invention, all belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0039] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as referring to the purpose, technical solutions and advantages of the methods. To be more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work indicate or imply relative importance or implicitly indicate the number of indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0040] Example 1 Refer to Figures 1 to 6 As shown, a preparation method of phosphorus trifluoride includes: S1: Phosphorus trichloride and anhydrous hydrogen fluoride are respectively added into the temperature - equalizing charging structure 2 of the reaction kettle 1. The reaction temperature of the reaction kettle 1 is maintained at 40 to 50 °C. The crude phosphorus trifluoride gas after the reaction is discharged along the discharge port 101 of the reaction kettle 1. A charging seat 102 is arranged on the reaction kettle 1. The temperature - equalizing charging structure 2 is locked on a sliding cylinder 3. The sliding cylinder 3 is slidably connected to the inner wall of the reaction kettle 1. The temperature - equalizing charging structure 2 includes a uniformly - distributed disk 201 movably installed in the reaction kettle 1. The uniformly - distributed disk 201 communicates with the charging seat 102. A multi - channel reaction structure 202 is connected below the uniformly - distributed disk 201. A multi - stage heat - exchange structure 203 is arranged inside the multi - channel reaction structure 202. A number of heat - exchange guide heads 204 are arranged on the reaction kettle 1. After the sliding cylinder 3 is installed in the reaction kettle 1, it rotates to make the multi - channel reaction structure 202 dock with the heat - exchange guide heads 204. The phosphorus trichloride and anhydrous hydrogen fluoride are mixed through the charging seat 102 and the uniformly - distributed disk 201 and then flow into the reaction kettle 1 through the multi - channel reaction structure 202; S2: The crude phosphorus trifluoride gas is condensed and then stored in the first storage tank. Then the liquid in the first storage tank is heated and pumped into a flash evaporator for flashing; S3: The gas after flashing is fed into a first distillation column for distillation. The hydrogen fluoride at the bottom of the distillation in the first distillation column is returned to the phosphorus trifluoride synthesis process. The phosphorus trifluoride and hydrogen chloride at the top of the distillation are condensed and then fed into an intermediate first product storage tank; S4: The material in the intermediate first product storage tank is pumped into a second distillation column for distillation. The gas at the top of the distillation in the second distillation column is condensed. Part of the condensed product is refluxed to the second distillation column, and part is stored in the first product storage tank; S5: The finished product in the first product storage tank is pumped into a vaporizer for vaporization. The vaporized gas enters a gas - liquid separation tank for separation. The separated liquid is refluxed to the vaporizer, and the separated gas is discharged from the top and sequentially fed into three phosphorus trifluoride purification devices for purification; S6: The purified gas is filtered through a filter. The filtered gas enters a second product storage tank. The gas in the second product storage tank is pressurized by a compressor and then enters a buffer tank for pressure stabilization storage, and then enters a filling system for filling after pressure stabilization.

[0041] During feeding, in order to facilitate the material distribution and mixing after feeding, the charging seat 102 includes a charging disk 1021 arranged inside the reaction kettle 1. A number of Y - type joints 1022 penetrating the reaction kettle 1 are arranged on the top of the charging disk 1021. The Y - type joints 1022 are respectively connected to the input ends of phosphorus trichloride and anhydrous hydrogen fluoride, so as to enable multi - stage segmented feeding.

[0042] In the existing preparation process of phosphorus trifluoride, a microchannel reactor is mostly used to delay the extremely fast heat exchange reaction process, so as to ensure the stability of the reaction products and the thoroughness of the reaction. Although the experimental purpose can be achieved, a special reactor is required, and enterprises need to purchase a variety of reactors for different reactions. Therefore, in this embodiment, through the sliding cylinder 3 arranged slidably, the temperature-uniforming material-changing structure 2 is arranged in the sliding cylinder 3, and then the position of the sliding cylinder 3 is adjusted so that the reaction of phosphorus trifluoride can be directly completed in the temperature-uniforming material-changing structure 2, and the product is then discharged to the purification stage through the reaction kettle 1, so that it can be directly completed in the reaction kettle 1 through a replaceable component. When preparing other chemical products and there is no need to accurately control the reaction conditions, the temperature-uniforming material-changing structure 2 can be directly removed, making the reaction kettle 1 become an ordinary reaction kettle, so as to directly achieve the effect of multi-purpose use of one device, and at the same time have the functions of normal mixing reaction and microchannel reaction.

[0043] During the installation process of the sliding cylinder 3, it needs to reach an accurate position, otherwise it is difficult to achieve the effects of inflow and outflow. Therefore, a barrier pile 103 is arranged inside the reaction kettle 1 of this embodiment, a number of universal guide wheels 301 are arranged on the outer side of the sliding cylinder 3, a convection column 302 is arranged at the bottom of the outer side surface of the sliding cylinder 3, and the convection column 302 is docked with the heat exchange guide head 204 after the sliding cylinder 3 rotates. The bottom of the sliding cylinder 3 is attached to the barrier pile 103, and universal guide wheels 301 are arranged on the outer side of the sliding cylinder 3, which can realize the rotation of the sliding cylinder 3 in the circumferential direction, so that the convection column 302 of the sliding cylinder 3 can form a stable connection with the heat exchange guide head 204.

[0044] In order to achieve the effect of a microchannel reactor in the temperature-uniforming material-changing structure 2, in this embodiment, a multi-channel reaction structure 202 is first arranged below the uniform distribution plate 201, so as to realize the long-path reaction of a single channel. Not only can the raw materials be poured through multiple channels, but also a relatively uniform mixing effect can be achieved in each channel, so as to achieve a uniform and stable reaction effect.

[0045] Due to the numerous channels of the multi-channel reaction structure 202, achieving the flow-through of multiple channels and the need for relatively long flow paths between multiple channels at the same time are pain points in the design. Therefore, the multi-channel reaction structure 202 of this embodiment includes a number of multi-flow tube columns 2021 connected to the distribution plate 201. The length of the multi-flow tube columns 2021 gradually increases from left to right. The multi-flow tube columns 2021 are docked with the outer ring tube 2022. The outer ring tube 2022 is closely attached to the inner side of the sliding cylinder 3 and the outer ring tubes 2022 are arranged at intervals. A downcomer 2023 is provided on the side of the multi-flow tube columns 2021 away from the distribution plate 201. The multi-channel reaction structure 202 uses multi-flow tube columns 2021 of different lengths and arranges the outer ring tubes 2022 at different heights, so as to achieve the dispersion of the flow path and the extension of the flow path, thereby achieving the effects of flow splitting and long diameter.

[0046] For the fluid after passing through the extended path of the outer ring tube 2022, if it is directly discharged into the reaction kettle 1 at this time, the relative distance is still not long enough. Therefore, the downcomer 2023 of this embodiment includes a downcomer head 20231 connected to the outer ring tube 2022. A multi-fold tube 20232 is connected below the downcomer head 20231. The lower end of the multi-fold tube 20232 is connected to a distribution head 20233. By providing the downcomer 2023 at the lower end of the outer ring tube 2022 and setting the main path of the downcomer 2023 as the multi-fold tube 20232, a pipeline structure with multiple bends can cause the fluid to form a turbulent flow phenomenon during flow, thereby improving the mixing effect.

[0047] Although the design of multiple multi-fold tubes 20232 improves the mixing effect, in fact, multiple thin and parallel multi-fold tubes 20232 will reduce the overall stability and will be relatively unstable when the fluid passes through. Therefore, adjacent multi-fold tubes 20232 of this embodiment are connected by a stabilizing belt 20234. The stabilizing belt 20234 on the outermost multi-fold tube 20232 is connected to the inner wall of the sliding cylinder 3. The multi-fold tubes 20232 are connected by the stabilizing belt 20234 and the multi-fold tubes 20232 are also connected to the sliding cylinder 3, thus forming a stable multi-section structure.

[0048] In order to reduce the flow rate of the fluid in the outer ring tube 2022, a corrugated layer 20235 is provided on the inner side of the outer ring tube 2022, so as to delay the flow of the fluid.

[0049] Although the multi-channel reaction structure 202 can achieve a long diameter and sufficient reaction effect, due to the relatively long structural path and variable route path of the multi-channel reaction structure 202, it is not easy to conduct heat exchange, so more heat will accumulate in the reaction kettle 1. Therefore, on the basis of the multi-channel reaction structure 202, the present invention is provided with a multi-stage heat exchange structure 203, which is embedded inside the multi-channel reaction structure 202 and is in full contact with the multi-channel reaction structure 202, so as to achieve the effect of rapid heat exchange in multiple parts.

[0050] Specifically, the multi-stage heat exchange structure 203 includes a horizontal accommodation part 2031 closely attached to the lower end of the uniform distribution plate 201. The lower end of the horizontal accommodation part 2031 is respectively connected to a horizontal embedding part 2032 and a vertical embedding part 2033. The horizontal embedding parts 2032 communicate with each other through a bending part 2034. The horizontal embedding parts 2032 are embedded in the gaps between the outer ring tubes 2022, and the vertical embedding parts 2033 are embedded on the outer side of the lower punching tube 2023. The horizontal embedding part 2032 and the vertical embedding part 2033 at the bottom are connected to a bottom accommodation part 2035, so that heat exchange can be carried out at all positions of the multi-channel reaction structure 202, and heat exchange wrapping can be carried out at multiple angles and multiple positions, so as to achieve the effect that even a complex structure can be simply heat-exchanged.

[0051] During heat exchange, it is mainly achieved through the circulation of the medium. Specifically, a heat flow guiding inlet head 20311 is provided on the horizontal accommodation part 2031, and a heat flow guiding outlet head 20312 is provided on the bottom accommodation part 2035. The heat flow guiding inlet head 20311 and the heat flow guiding outlet head 20312 are both connected to a heat exchange guiding head 204, so that the replacement of the medium can be realized and real-time heat exchange can be carried out.

[0052] Embodiment 2 Refer to Figures 7 to 14As shown in the figure, another embodiment of the present invention further provides a phosphorus trifluoride purification device. The phosphorus trifluoride purification device includes an adsorption tower body 10 for adsorbing phosphorus trifluoride. A top cover 20 is movably arranged at the top of the adsorption tower body 10. A plurality of air inlet ends are connected to the top cover 20. An air outlet end 30 is arranged at the bottom of the adsorption tower body 10. It further includes: a two-position sliding molecular sieve structure 40, which includes a first molecular sieve adsorption cylinder 41 arranged at the inner bottom of the adsorption tower body 10. A second molecular sieve adsorption cylinder 42 is arranged above the first molecular sieve adsorption cylinder 41. The first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42 are both locked to the inner wall of the adsorption tower body 10. The effective pore diameter of the second molecular sieve adsorption cylinder 42 is larger than that of the first molecular sieve adsorption cylinder 41. The phosphorus trifluoride enters the first molecular sieve adsorption cylinder 41 after being adsorbed by the second molecular sieve adsorption cylinder 42; a pressure variable diameter adjustment structure 50 arranged between the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42. The pressure variable diameter adjustment structure 50 includes an elastic adjustment component 51 arranged on the inner side wall of the adsorption tower body 10. The upper and lower ends of the elastic adjustment component 51 are respectively connected to the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42. A pressure adjustment disc 52 is connected to the middle of the elastic adjustment component 51. A plurality of holes 521 for passing chlorine trifluoride are opened on the pressure adjustment disc 52. An inner barrier structure 53 is arranged in the holes 521. A top bone component 54 is fixedly arranged at the top of the first molecular sieve adsorption cylinder 41. When the pressure adjustment disc 52 is pressed and descends, it will squeeze the top bone component 54, and the top bone component 54 will push out the inner barrier structure 53 in the holes 521, making the inner diameter of the holes 521 smaller.

[0053] The first molecular sieve adsorption cylinder 41 is located below the second molecular sieve adsorption cylinder 42. In order to fix the first molecular sieve adsorption cylinder 41, a bearing socket 13 is arranged at the inner bottom of the adsorption tower body 10. The first molecular sieve adsorption cylinder 41 is installed in the bearing socket 13.

[0054] In the prior art, molecular sieves are often used to purify the post-processing of phosphorus trifluoride. The molecular sieves are used to perform the last step of treatment on the impurities of phosphorus trifluoride. When arranging the molecular sieves, a very large accommodating framework is usually adopted, and the molecular sieves are filled into the framework. If the molecular sieves in the upper part are pulverized and blocked, it will directly cause the molecular sieves in the lower part to be unusable and need to be directly replaced. Therefore, through the double-position sliding molecular sieve structure 40 provided in the present invention, by arranging at both ends of the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42, the second molecular sieve adsorption cylinder 42 with a larger effective pore diameter is placed at the upper end of the first molecular sieve adsorption cylinder 41 with a larger volume, so that the second molecular sieve adsorption cylinder 42 bears the first-stage pressure of the gas. Even if the second molecular sieve adsorption cylinder 42 is pulverized, only the upper half part needs to be replaced. And the first molecular sieve adsorption cylinder 41 with a large volume, because it is arranged at the lower end, has a lower possibility of being directly impacted by a large amount of high-pressure gas, so that its blockage phenomenon can be weakened, the service life is longer, and at the same time, it is relatively low in terms of enterprise cost and higher in economic benefits.

[0055] The existing molecular sieves need to be regenerated after being taken out, and the regeneration method often adopts the reverse blowing regeneration method. Since the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42 need to be replaced, especially the second molecular sieve adsorption cylinder 42, whose replacement frequency is higher than that of the first molecular sieve adsorption cylinder 41, it needs to be set to be movable, but it cannot be in a suspended state. Therefore, a guide rail 11 is arranged inside the adsorption tower body 10 in this embodiment, an inner groove 12 is formed by the outer wall of the adsorption tower body 10 being recessed inward, the structures of the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42 are the same, the first molecular sieve adsorption cylinder 41 includes a material placing frame 411 for carrying the molecular sieves, a plurality of matching rib grooves 412 are arranged on the outer side of the material placing frame 411, after the material placing frame 411 is placed into the adsorption tower body 10, the matching rib grooves 412 are matched with the guide rail 11, and a plurality of limiting members 413 are arranged on the inner groove 12, the limiting members 413 penetrate through the guide rail 11 and are connected with the matching rib grooves 412. By arranging a guide rail 11 inside the adsorption tower body 10 and arranging matching rib grooves 412 on the outer sides of the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42, through the way of sliding and placing, the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42 can reach and be specified at the designated positions, and the sealing performance can be ensured during the fixing process.

[0056] When replacing the first molecular sieve adsorption cylinder 41 and the second molecular sieve adsorption cylinder 42, the upper cover 20 needs to be disassembled. Once the upper cover 20 is disassembled, the gas remaining in the equipment will leak out, which may cause pollution. Therefore, before disassembling the upper cover 20, the gas in the adsorption tower body 10 needs to be replaced. During gas replacement, nitrogen is introduced through the nitrogen inlet at the top of the equipment, and the nitrogen causes the gas in the adsorption tower body 10 and the molecular sieve to flow out through the nitrogen outlet at the bottom of the adsorption tower body 10, so as to ensure safety after the upper cover 20 is opened.

[0057] In order to ensure the sealing effect, alignment holes are provided in the inner groove 12. The limiting member 413 includes a sealing gasket 4131 provided on the alignment hole. A locking nail 4132 is installed on the sealing gasket 4131. The locking nail 4132 penetrates through the sealing gasket 4131 and is connected to the threaded hole on the mating rib groove 412. Through the limiting member 413, while fixing the molecular sieve adsorption cylinder, the leakage of the gas flowing through it can be avoided.

[0058] Although the second molecular sieve adsorption cylinder 42 is used to bear the pressure instead of the first molecular sieve adsorption cylinder 41, in fact, the first molecular sieve adsorption cylinder 41 may still be directly affected by high-pressure gas. In order to protect the first molecular sieve adsorption cylinder 41 without affecting the filtration efficiency, the present invention provides a pressure variable-diameter adjustment structure 50 on the basis of the double-position sliding molecular sieve structure 40. When the pressure of the incoming phosphorus trifluoride gas is too high, it will directly press down the pressure adjustment disc 52 installed on the elastic adjustment component 51, so that the pressure adjustment disc 52 touches the top bone component 54, and the top bone component 54 will push out the inner barrier structure 53 in the hole 521, so that the inner diameter of the hole 521 becomes smaller, and the available passage area of the gas passing through the hole 521 after passing through the second molecular sieve adsorption cylinder 42 becomes smaller, so that the pressure and speed of the gas are both weakened, so as to ensure that the gas passes through the first molecular sieve adsorption cylinder 41 at a relatively uniform and stable speed. While the gas is stably filtered, the purification equipment has a longer service life.

[0059] In order to sense the gas flow rate and pressure changes so as to automatically adjust its own state changes, in this embodiment, the elastic adjustment component 51 includes at least two elastic adjustment seats. The elastic adjustment seat includes a first limit spring 511 provided at the lower end of the second molecular sieve adsorption cylinder 42, and a second limit spring 512 is provided at the edge of the upper end of the first molecular sieve adsorption cylinder 41. An installation platform 513 is connected between the first limit spring 511 and the second limit spring 512. A pressure adjustment disc 52 is accommodated in the installation platform 513. The pressure adjustment disc 52 is arranged between the first limit spring 511 and the second limit spring 512. The expansion and contraction amounts of the first limit spring 511 and the second limit spring 512 are changed by the pressure when the gas enters, and then it is judged whether to trigger the internal blocking structure 53 in the pressure adjustment disc 52, so that the state can be automatically changed according to the gas change without manual monitoring.

[0060] It should be emphasized that the first limit spring 511 and the second limit spring 512 are sleeve-type springs, that is, the springs are limited by the sleeves to prevent them from falling out directly.

[0061] During the fixing process of the pressure adjustment disc 52, it needs to change dynamically according to the states of the first limit spring 511 and the second limit spring 512. Therefore, the installation platform 513 in this embodiment includes a C-shaped ferrule 5131 connected to the first limit spring 511 and the second limit spring 512. The opening of the C-shaped ferrule 5131 is used to accommodate the pressure adjustment disc 52. A perforation is provided on the side of the pressure adjustment disc 52 away from the opening, and a positioning pin 5132 for locking the pressure adjustment disc 52 is connected to the perforation. The pressure adjustment disc 52 is slidably fixed inside the adsorption tower body 10 through the C-shaped ferrule 5131 and can move synchronously with the first limit spring 511 and the second limit spring 512, so as to achieve the effect of automatic adjustment.

[0062] When adjusting the gas pressure and gas volume, it mainly adjusts the flow rate through the pressure adjustment disc 52. Therefore, the pressure adjustment disc 52 in this embodiment includes a pressure movable disc 522 connected to the C-shaped ferrule 5131. The hole 521 is opened in the axial direction of the pressure movable disc 522. A plurality of axial flow channels 523 are provided inside the pressure movable disc 522. The axial flow channels 523 communicate with a reflux channel 524 laterally. The internal blocking structure 53 is located in the reflux channel 524. By providing the axial flow channels 523 on the pressure adjustment disc 52 and passing the gas through the axial flow channels 523, and when adjustment is needed, the ventilation volume of the axial flow channels 523 is changed. Therefore, a reflux channel 524 is provided beside each axial flow channel 523, and the internal blocking structure 53 is exactly arranged in the reflux channel 524, so that the ventilation volume of the axial flow channels 523 can be changed.

[0063] It is the internal barrier structure 53 that changes the diameter of the axial flow channel 523. The internal barrier structure 53 includes a trigger part 531 located inside the return flow channel 524. The trigger part 531 is connected to a barrier part 532. After the trigger part 531 is lifted by the skull assembly 54, the barrier part 532 is pushed out, so that the barrier part 532 extends into the axial flow channel 523. One end of the internal barrier structure 53 is triggered by the skull assembly 54. When the entire pressure regulating disc 52 descends, it will contact the skull assembly 54, thereby pushing out the trigger part 531, and then driving the barrier part 532 to be pushed out, so as to realize the transformation of the diameter. After the gas pressure drops, the pressure regulating disc 52 rises, and the barrier part 532 will also swing down automatically under the action of gravity, without hindering the normal flow of gas.

[0064] Among them, the barrier part 532 is a folding piece, and the folding piece is provided with a plurality of flow holes. Even if some gas enters the return flow channel 524 through the undeveloped barrier part 532, it will be blocked by the skull assembly 54.

[0065] During the cooperation between the skull assembly 54 and the return flow channel 524, it needs to cooperate with a plurality of return flow channels 524 in order to achieve the effect of consistent adjustment. Therefore, the skull assembly 54 of this embodiment includes an extension rod seat 541 fixed on the top surface of the first molecular sieve adsorption cylinder 41. A plurality of separation rods 542 are connected to the top surface of the extension rod seat 541. The separation rods 542 extend to the return flow channel 524 and are arranged at intervals with the trigger part 531. By setting the skull assembly 54 as a plurality of separation rods 542, the plurality of separation rods 542 cooperate with the descending return flow channel 524, so that the ventilation volume in all the return flow channels 524 can be adjusted consistently, and the gas pressure can be better stabilized.

[0066] Since the actions of changing the fluid flow rate are all automatically adjusted inside the device, it is difficult for experimenters to know the situation of the molecular sieve inside and the replacement cycle of the molecular sieve. Therefore, the present invention sets a pressure detection structure inside the adsorption tower body 10. By detecting the gas pressure at different positions of the adsorption tower body 10, it can be judged whether there is resistance when the gas passes through the molecular sieve, and then it can be judged whether the molecular sieve needs to be replaced, so as to achieve the effects of mechanical self-adjustment and intelligent self-inspection.

[0067] Since the actions of changing the fluid flow rate are automatically adjusted inside the device, it is difficult for the experimenters to know the situation of the molecular sieve inside and the replacement cycle of the molecular sieve. Therefore, the pressure detection structure of this embodiment includes a first pressure detector 141 arranged at the top inside the adsorption tower body 10, and a second pressure detector 142 is arranged at the bottom inside the adsorption tower body 10. By arranging a pressure detection structure inside the adsorption tower body and detecting the gas pressure at different positions of the adsorption tower body, it is possible to determine whether the gas is subject to resistance when passing through the molecular sieve, and then determine whether the molecular sieve needs to be replaced, so as to achieve the effects of mechanical self-adjustment and intelligent self-checking.

[0068] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing phosphorus trifluoride, characterized in that, Including: S1: Phosphorus trichloride and anhydrous hydrogen fluoride are respectively added into the temperature-uniforming and material-changing structure (2) of the reaction kettle (1). The reaction temperature of the reaction kettle (1) is maintained at 40 to 50 °C. The crude phosphorus trifluoride gas after the reaction is discharged along the discharge port (101) of the reaction kettle (1). A feeding seat (102) is arranged on the reaction kettle (1). The temperature-uniforming and material-changing structure (2) is locked on a sliding cylinder (3). The sliding cylinder (3) is slidably connected with the inner wall of the reaction kettle (1). The temperature-uniforming and material-changing structure (2) includes a uniform distribution plate (201) movably installed in the reaction kettle (1). The uniform distribution plate (201) communicates with the feeding seat (102). A multi-channel reaction structure (202) is connected below the uniform distribution plate (201). A multi-stage heat exchange structure (203) is arranged inside the multi-channel reaction structure (202). A number of heat exchange guide heads (204) are arranged on the reaction kettle (1). After the sliding cylinder (3) is installed in the reaction kettle (1), it rotates to make the multi-channel reaction structure (202) dock with the heat exchange guide heads (204). The phosphorus trichloride and anhydrous hydrogen fluoride are mixed through the feeding seat (102), the uniform distribution plate (201) and the multi-channel reaction structure (202) and then flow into the reaction kettle (1). S2: The crude phosphorus trifluoride gas is condensed and then stored in a first storage tank. Then the liquid in the first storage tank is heated and pumped into a flash evaporator for flashing. S3: The gas after flashing is fed into a first distillation column for distillation. The hydrogen fluoride at the bottom of the distillation in the first distillation column is returned to the phosphorus trifluoride synthesis process. The phosphorus trifluoride and hydrogen chloride at the top of the distillation are condensed and then fed into an intermediate first product storage tank. S4: The material in the intermediate first product storage tank is pumped into a second distillation column for distillation. The gas at the top of the distillation in the second distillation column is condensed. Part of the condensed product is refluxed to the second distillation column, and part is fed into the first product storage tank for storage. S5: The finished product in the first product storage tank is pumped into a vaporizer for vaporization. The gas after vaporization enters a gas-liquid separation tank for separation. The separated liquid is refluxed to the vaporizer, and the separated gas is discharged from the top and sequentially fed into three phosphorus trifluoride purification devices for purification. S6: The purified gas is fed into a filter for filtration. The filtered gas enters a second product storage tank. The gas in the second product storage tank is pressurized by a compressor and then enters a buffer tank for pressure stabilization storage. After pressure stabilization, it enters a filling system for filling.

2. The preparation method of phosphorus trifluoride according to claim 1, characterized in that, The feeding seat (102) includes a feeding plate (1021) arranged inside the reaction kettle (1). A number of Y-shaped joints (1022) penetrating the reaction kettle (1) are arranged on the top of the feeding plate (1021). The Y-shaped joints (1022) are respectively connected to the input ends of phosphorus trichloride and anhydrous hydrogen fluoride.

3. The preparation method of phosphorus trifluoride according to claim 1, characterized in that, Inside the reactor (1), a barrier pile (103) is provided. On the outer side of the sliding cylinder (3), a number of universal guide wheels (301) are provided. At the bottom of the outer side surface of the sliding cylinder (3), a convection column (302) is provided. After the sliding cylinder (3) rotates, the convection column (302) is docked with the heat exchange guide head (204). The bottom of the sliding cylinder (3) is attached to the barrier pile (103).

4. A method for preparing phosphorus trifluoride according to claim 1, characterized in that, The multi-channel reaction structure (202) includes a number of multi-flow tube columns (2021) connected to the uniform distribution plate (201). The length of the multi-flow tube columns (2021) gradually increases from left to right. The multi-flow tube columns (2021) are docked with the outer ring tube (2022). The outer ring tubes (2022) are closely attached to the inner side of the sliding cylinder (3) and are spaced apart from each other. On the side of the multi-flow tube columns (2021) away from the uniform distribution plate (201), a downrush tube (2023) is provided.

5. The preparation method of phosphorus trifluoride according to claim 4, characterized in that, The downrush tube (2023) includes a downrush head (20231) connected to the outer ring tube (2022). Below the downrush head (20231), a multi-fold tube (20232) is connected. The lower end of the multi-fold tube (20232) is connected to a distribution head (20233).

6. The preparation method of phosphorus trifluoride according to claim 5, characterized in that, Adjacent multi-fold tubes (20232) are connected by a stabilizing band (20234). The stabilizing band (20234) on the outermost multi-fold tube (20232) is connected to the inner wall of the sliding cylinder (3).

7. A method for preparing phosphorus trifluoride according to claim 4, characterized in that, A wrinkled layer (20235) is provided on the inner side of the outer ring tube (2022).

8. The preparation method of phosphorus trifluoride according to claim 4, characterized in that, The multi-stage heat exchange structure (203) includes a horizontal accommodation part (2031) closely attached to the lower end of the uniform distribution plate (201). The lower end of the horizontal accommodation part (2031) is respectively connected to a horizontal embedding part (2032) and a vertical embedding part (2033). The horizontal embedding parts (2032) communicate with each other through a bending part (2034). The horizontal embedding parts (2032) are embedded in the gaps between the outer ring tubes (2022). The vertical embedding part (2033) is embedded on the outer side of the downrush tube (2023). The lowermost horizontal embedding part (2032) and the vertical embedding part (2033) are connected into a bottom accommodation part (2035).

9. The preparation method of phosphorus trifluoride according to claim 8, characterized in that, A heat flow guiding inlet head (20311) is provided on the horizontal accommodation part (2031). A heat flow guiding outlet head (20312) is provided on the bottom accommodation part (2035). Both the heat flow guiding inlet head (20311) and the heat flow guiding outlet head (20312) are connected to the heat exchange guide head (204).

Images