A reaction and separation integrated preparation tower for phosphorus oxyfluoride

Abstract

The invention discloses a phosphorus oxyfluoride reaction and separation integrated preparation tower, which belongs to the field of industrial equipment for phosphorus oxyfluoride preparation. The preparation tower comprises a tower body, a feeding zone, a reaction zone and a separation zone are arranged in the tower body, and the feeding zone and the separation zone are both filled with a packing section of a packing, wherein a first feed port is arranged at the bottom of the packing section in the feeding zone, a tube-in-tube heat exchanger is arranged in each reaction zone, a threaded tube is arranged on the tube-in-tube heat exchanger, and fillers are also filled between the threaded tubes, wherein a second feed port is arranged at the upper part of the reaction zone located in the top layer, polyphosphoric acid and anhydrous hydrogen fluoride contact in the reaction zone to form a step-by-step reaction of concentration and temperature, and the phosphorus oxyfluoride gas generated after the reaction is fractionated through the packing section on the separation zone and enters the next process at the top of the tower body. The invention integrates the reaction and separation of phosphorus oxyfluoride production, reduces the energy consumption of phosphorus oxyfluoride production, reduces the production cost, and improves the reaction yield.

Description

Technical Field

[0001] The invention relates to the field of industrial equipment for preparing phosphorus oxyfluoride, and in particular to a phosphorus oxyfluoride reaction and separation integrated preparation tower. Background Art

[0002] At present, phosphorus oxyfluoride (POF 3 ) is a colorless gas with a pungent odor under normal conditions, emitting faint smoke in the air. Phosphorus oxyfluoride (POF 3 ) is mainly prepared by using CaF 2 It reacts with anhydrous sulfurous acid to generate CaF(SO 3 F), and then with H 3 PO 4 The intermediate product POF is generated by the reaction 3 However, due to CaF 2 It is solid, and continuous production is difficult, the process is complicated, and the production cost is high.

[0003] To this end, the applicant previously proposed a method for preparing high-purity phosphorus oxytrifluoride by continuous reactive distillation (patent application number CN2022114628326), which discloses polyphosphoric acid and anhydrous hydrogen fluoride as raw materials, and through continuous reactive distillation, first reacting in a reactive distillation tower and then further distilling through a first distillation tower to obtain a product with a purity of more than 99.99%.

[0004] However, in the actual application of the method for preparing high-purity phosphorus oxyfluoride by continuous reactive distillation, it is found that the equipment for preparing phosphorus oxyfluoride is numerous and complicated due to the method of using the reaction first and then separation. Moreover, in the reactive distillation tower, since polyphosphoric acid is a liquid and anhydrous hydrogen fluoride is a gas, the polyphosphoric acid and anhydrous hydrogen fluoride have a short contact time during the process of two-phase contact through the tower plate, so that the reaction between polyphosphoric acid and anhydrous hydrogen fluoride is insufficient, and the cyclic reaction must be achieved by controlling the reflux, which increases the energy consumption of the production reaction. The concentration of the reaction liquid on the tower plate is uneven, so that the concentration of some parts of the reaction is too high, and the side reactions become more, and the concentration of some parts of the reaction is too low, so that the reaction is incomplete. Therefore, a lot of waste is discharged at the bottom of the reactive distillation tower, which is not conducive to improving the reaction yield between polyphosphoric acid and anhydrous hydrogen fluoride.

[0005] Therefore, in the actual production process, the applicant has designed a phosphorus oxyfluoride reaction and separation integrated preparation tower after research, the purpose of which is to solve the problem of insufficient contact between polyphosphoric acid and anhydrous hydrogen fluoride during the reaction process, and at the same time effectively separate high-purity concentration phosphorus oxyfluoride, thereby reducing the energy consumption of phosphorus oxyfluoride production, reducing production costs, and improving the reaction yield between polyphosphoric acid and anhydrous hydrogen fluoride. Summary of the invention

[0006] In view of the technical problems existing in the above-mentioned prior art, the present invention provides an integrated preparation tower for phosphorus oxyfluoride reaction and separation, which can effectively solve the technical problems existing in the above-mentioned prior art.

[0007] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0008] A phosphorus oxyfluoride reaction and separation integrated preparation tower comprises a tower body, wherein a feed zone, a plurality of reaction zones and a separation zone are sequentially arranged in the tower body from bottom to top, the feed zone and the separation zone in the tower body are both filled with a packing section of a packing, a cyclone distributor is arranged between the feed zone and the reaction zone, between the separation zone and the reaction zone, and between the plurality of reaction zones, wherein a first feed port for anhydrous hydrogen fluoride to enter is arranged at the bottom of the packing section in the feed zone, a shell-and-tube heat exchanger is arranged in each of the reaction zones, a threaded pipe for controlling the reaction temperature is arranged on the shell-and-tube heat exchanger, and the Fillers are also filled between the threaded tubes, wherein a second feed port for feeding polyphosphoric acid is provided at the upper part of the reaction zone located at the top layer, and polyphosphoric acid contacts anhydrous hydrogen fluoride on the fillers between the threaded tubes dispersed in the reaction zone to form a step-by-step reaction of concentration, and the reaction temperatures of the multiple reaction zones are controlled from the bottom of the tower body upwards through the shell-and-tube heat exchanger to a step-by-step reaction temperature of 80-120° C., so that the phosphorus oxyfluoride gas generated after the reaction is fractionated through the filler section on the separation zone and enters the next process at the top product outlet at the top of the tower body.

[0009] Furthermore, the swirl distributor is provided with a plurality of swirl plates arrayed along its central circumference, and the acute angle θ between the swirl plates and the bottom surface of the swirl distributor is 30° to 60°. The swirl distributor can achieve uniform distribution of the rising channels of the gas flow inside the feed zone and the plurality of reaction zones, so that the reaction gas can be better dispersed between the fillers inside the tower body, and sufficient contact between the reaction gas and the reaction liquid is achieved, so that the reaction is more sufficient and complete, and the rising gas in the reaction system is turned and diffused by the inclined arrangement of the plurality of swirl plates, so as to achieve an axially upward swirl effect.

[0010] Furthermore, the swirl plate has a plurality of corrugated protrusions arranged in a wavy curve in the vertical direction on its two surfaces, and the cross section of the corrugated protrusion is in a semicircular arc shape. The wavy curve of the corrugated protrusion is in a wavy shape so that the rising gas attached to the two surfaces of the swirl plate can increase the fluctuating diffusion effect of the gas in the radial direction through the ups and downs on both sides of the corrugated protrusion. At the same time, the reaction liquid settling downwards collides and disperses during the descent due to the wavy curve, thereby avoiding the wall flow of the reaction liquid. The cross section of the corrugated protrusion is in a semicircular arc shape, so that there is an arc transition between the swirl plate surface and the corrugated protrusion to avoid dead corners.

[0011] Furthermore, the shell-and-tube heat exchanger includes inlet and outlet main pipes arranged at the upper and lower parts, and each of the inlet and outlet main pipes is evenly provided with a plurality of horizontal and vertical branch pipes with a distribution of lengths in the axial direction, and a plurality of the threaded pipes are evenly arranged between the corresponding branch pipes at the upper and lower parts. The shell-and-tube heat exchanger is heated by connecting the threaded pipes, so that the heating path of the threaded pipes becomes longer, further increasing the contact between the threaded pipes and the fillers, thereby increasing the heating area of ​​the shell-and-tube heat exchanger, so that the shell-and-tube heat exchanger can more accurately control the reaction temperature of the reaction zone, ensuring the stability and sufficiency of the reaction. Moreover, due to the use of the threaded structure, the polyphosphoric acid liquid flowing downward in the reaction zone is not easy to form a wall flow effect on the threaded pipe wall surface on the shell-and-tube heat exchanger, thereby increasing the sufficiency of the reaction of the polyphosphoric acid.

[0012] Furthermore, the reaction zone is configured as two sections, wherein the temperature of the lower reaction zone is controlled at 80-100°C, and the temperature of the upper reaction zone is controlled at 100-120°C.

[0013] Furthermore, the filler filled inside the reaction zone is a saddle-shaped filler.

[0014] Furthermore, the inner diameter of the spiral of the threaded pipe is 60-150 mm, and the pitch of the spiral is 50-100 mm.

[0015] Furthermore, for the plurality of reaction zones, the spiral directions of the threaded tubes of the tube-in-tube heat exchangers between the upper and lower adjacent reaction zones are arranged in opposite directions.

[0016] Furthermore, the tower body is provided with a structural redistributor at an upper portion of the separation zone.

[0017] Furthermore, the tower body is provided with a wire mesh demister at an upper portion of the structural redistributor.

[0018] The present invention sets a multi-stage reaction zone, and polyphosphoric acid flows from the upper part of the reaction zone to the surface of the filler in the reaction zone, and contacts and reacts with the rising anhydrous hydrogen fluoride gas on the reaction zone. In the upper reaction zone, the concentration of polyphosphoric acid is high and the concentration of anhydrous hydrogen fluoride is low, so that the polyphosphoric acid can completely react with the anhydrous hydrogen fluoride gas to form phosphorus oxyfluoride gas, and avoids the excess anhydrous hydrogen fluoride from being lifted to the separation zone together with the generated phosphorus oxyfluoride gas through the upper reaction zone. Therefore, through the above setting, the purity of the phosphorus oxyfluoride gas can be greatly improved; in the lower reaction zone, the concentration of polyphosphoric acid is low, but the concentration of anhydrous hydrogen fluoride is high, and the anhydrous hydrogen fluoride in the reaction zone completely reacts with the polyphosphoric acid. Therefore, the multi-stage reaction zone makes the reaction between polyphosphoric acid and anhydrous hydrogen fluoride more gentle, stable, and more complete through the step-by-step reaction of the step-by-step concentration, and avoids the excess polyphosphoric acid from remaining at the bottom of the tower body through the reaction zone and the feed zone.

[0019] The present invention uses a shell-and-tube heat exchanger provided with threaded tubes to better realize accurate control of the temperature of the reaction system in the reaction zone, ensure the temperature stability of the reaction system, avoid fluctuations in the reaction temperature of the reaction zone, and reduce the occurrence of side reactions in the reaction zone. Moreover, by using a multi-stage reaction zone and a corresponding shell-and-tube heat exchanger, step-by-step control is achieved on the reaction temperature inside different reaction zones, ensuring the reaction temperature requirements of the reaction system at different concentration stages, and improving the reaction efficiency between polyphosphoric acid and anhydrous hydrogen fluoride.

[0020] The present invention increases the resistance and path of the rising gas of phosphorus oxyfluoride by using fillers through the upper separation zone, so that the mist of polyphosphoric acid entrained in the rising gas of phosphorus oxyfluoride is accumulated and absorbed through contact with the surface of the fillers and flows back into the reaction zone after settling. Therefore, the separation of phosphorus oxyfluoride and the entrained polyphosphoric acid mist can be well achieved through the separation zone, and the purity of the phosphorus oxyfluoride product is improved. In addition, a structural redistributor and a wire mesh demister are arranged on the upper part of the tower body, and the phosphorus oxyfluoride entrained in the phosphorus oxyfluoride can be further removed by the wire mesh demister, and the captured mist and the generated liquid enter the separation zone through the structural redistributor to achieve gas-liquid separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of a tower for preparing phosphorus oxyfluoride.

[0022] Figure 2 It is a schematic diagram of the three-dimensional structure of the swirl distributor.

[0023] Figure 3 A top view of the swirl distributor.

[0024] Figure 4 It is a cross-sectional schematic diagram of the swirl distributor.

[0025] Figure 5 It is a schematic diagram of the three-dimensional structure of the tube-in-tube heater.

[0026] Figure 6 This is the front view of the tube heater.

[0027] Figure 7 A top view of a tube heater.

[0028] Among them: 61-tower body, 611-first feed inlet, 612-second feed inlet, 613-installation hole, 614-tower bottom waste outlet, 615-tower top product outlet, 62-filling section, 63-tube heat exchanger, 631-inlet and outlet main pipe, 632-branch pipe, 633-threaded pipe, 634-flange, 64-swirl distributor, 641-swirl plate, 642-corrugated protrusion, 65-structured redistributor, 66-wire mesh demister. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are briefly described below in conjunction with the accompanying drawings.

[0030] A phosphorus oxyfluoride reaction and separation integrated preparation tower, referring to Figure 1 , comprising a tower body 61, wherein the tower body 61 is provided with a feed zone, a plurality of reaction zones and a separation zone in sequence from bottom to top, the feed zone and the separation zone inside the tower body 61 are both filled with a packing section 62 of packing, a cyclone distributor 64 is provided between the feed zone and the reaction zone, between the separation zone and the reaction zone, and between the plurality of reaction zones, the side wall surface of the tower body 61 is provided with mounting holes 613 for the installation and maintenance of packing at both ends of the feed zone, each reaction zone, and the separation zone, wherein a first feed port 611 for anhydrous hydrogen fluoride to enter is provided at the bottom of the packing section 62 in the feed zone, the anhydrous hydrogen fluoride is dispersed through the packing of the packing section 62, and is further dispersed and lifted to the reaction zone by the cyclone distributor 64, each reaction zone is provided with a tube-in-tube heat exchanger 63, and the tube-in-tube heat exchanger 63 is provided with a threaded pipe 633 for controlling the reaction temperature, refer to Figure 5 , Figure 6 , Figure 7The shell-and-tube heat exchanger 63 includes an inlet and outlet main pipe 631 arranged at the upper and lower parts, and a plurality of horizontal and vertical branch pipes 632 with length distribution are evenly arranged in the axial direction of each inlet and outlet main pipe 631. A plurality of threaded pipes 633 are evenly arranged between the upper and lower corresponding branch pipes 632. The plurality of branch pipes 632 are arranged in a circular shape according to the internal cross-sectional shape of the tower body 61, so that the threaded pipes 633 between the plurality of branch pipes 632 can be well evenly distributed vertically in the reaction zone of the tower body 61. A flange 634 is arranged at the end of the inlet and outlet main pipe 631 for connection with an external heating steam pipeline. In the reaction zone, fillers are also filled between the threaded pipes 633, and polyphosphoric acid is discharged from the reaction zone. During the flow of the liquid phase to the bottom, part of the polyphosphoric acid will flow along the outer wall surface of the threaded tube 633 to form a wall flow effect. However, after the reaction zone is filled with fillers, the fillers and the outer wall of the threaded tube 633 are in contact with the fillers, and the polyphosphoric acid on the outer wall surface of the threaded tube 633 by the wall flow will be dispersed on the filler surface through natural drainage under the action of swirl inertia. Therefore, the cooperation between the threaded tube 633 and the filler can well prevent the wall flow effect of the threaded tube 633. At the same time, due to its spiral setting, the heating length and heating area of ​​the threaded tube 633 are increased, thereby increasing the internal heating effect of the threaded tube 633 on the reaction zone.

[0031] A second feed port 612 for feeding polyphosphoric acid is provided at the upper part of the reaction zone located at the top layer. After the polyphosphoric acid is fed through the second feed port 612, it is dispersed in the reaction zone by the cyclone distributor 64. The polyphosphoric acid flows from the top reaction zone to the lower bottom reaction zone through dispersion. The polyphosphoric acid contacts the anhydrous hydrogen fluoride on the filler between the threaded tubes 633 dispersed in the reaction zone to form a step-by-step reaction of concentration. The reaction temperature of the multiple reaction zones is controlled from the bottom of the tower body 61 to the top through the shell-and-tube heat exchanger 63 to be a step-by-step reaction temperature of 80-120° C., so that the phosphorus oxyfluoride gas generated after the reaction is fractionated through the filler section 62 on the separation zone and enters the next process at the top product outlet 615 at the top of the tower body 61. The excess polyphosphoric acid liquid and a small amount of side reaction liquid residue can be regularly discharged through the bottom waste outlet 614 of the tower body 61 for centralized collection and treatment.

[0032] In the present invention, in order to better achieve the dispersion effect of the filler inside the reaction zone, the filler filled inside the reaction zone is preferably a saddle-shaped filler, and the specifications of the saddle-shaped filler are 38mm×30mm×0.8mm (outer diameter×height×thickness) or 50mm×40mm×1.0mm (outer diameter×height×thickness). Correspondingly, the spiral inner diameter of the threaded tube 633 of the shell-and-tube heat exchanger 63 is 60~150mm, and the pitch of the spiral is 50~100mm, so that one or more saddle-shaped fillers can be placed inside the spiral of the threaded tube 633 and between the pitches of the upper and lower spirals, thereby ensuring the installation and placement of the saddle-shaped filler. During the process of filling the saddle-shaped filler inside the spiral of the threaded tube 633 of the shell-and-tube heat exchanger 63, the saddle shape of the saddle-shaped filler and the spiral direction of the threaded tube 633 are placed in contact with each other, so that the outer wall surface of the threaded tube 633 and the saddle shape of the saddle-shaped filler are better fitted, further ensuring that the polyphosphoric acid flowing on the outer wall surface of the threaded tube 633 can be well dispersed in the reaction zone through the saddle-shaped filler.

[0033] In the present invention, the spiral directions of the threaded tubes 633 of the shell-and-tube heat exchangers 63 between the upper and lower adjacent reaction zones in the multiple reaction zones are set in opposite directions. In this way, it can be well ensured that the polyphosphoric acid can achieve staggered dispersed flow in the process of passing through the adjacent reaction zones, thereby achieving a better dispersion effect.

[0034] In the present invention, the reaction liquid and reaction gas in the tower body 61 are uniformly dispersed in the packing in the reaction zone by the cyclone distributor 64. To further improve the dispersion effect, the cyclone distributor 64 can refer to Figure 2 , Figure 3 and Figure 4The swirl distributor 64 is provided with a plurality of swirl plates 641 arranged along its central circumference, and the acute angle θ between the swirl plates 641 and the bottom surface of the swirl distributor 64 is inclined at 30° to 60°. Preferably, the acute angle θ is set to 45°. The swirl distributor 64 can achieve uniform distribution of the rising channels of the gas flow inside the feed zone and the plurality of reaction zones, so that the reaction gas can be better dispersed between the fillers inside the tower body 61, achieving full contact between the reaction gas and the reaction liquid, making the reaction more sufficient and complete. The rising gas in the reaction system is turned and diffused by the inclined plurality of swirl plates 641, achieving an axially upward swirl effect. At the same time, as a further embodiment, it can also A plurality of corrugated protrusions 642 are arranged on the two surfaces of the swirl plate 641 in a wavy curve in the vertical direction, and the cross-section of the corrugated protrusion 642 is in a semicircular arc shape. The wavy curve of the corrugated protrusion 642 is in a winding shape, so that the rising gas attached to the two surfaces of the swirl plate 641 can increase the fluctuation and diffusion effect of the gas in the radial direction through the undulation on both sides of the corrugated protrusion 642, thereby further increasing the dispersion effect of the rising gas. At the same time, the reaction liquid settling downward collides and disperses during the descent due to the winding corrugated curve, thereby avoiding the wall flow of the reaction liquid. The cross-section of the corrugated protrusion 642 is in a semicircular arc shape, so that there is an arc transition between the surface of the swirl plate 641 and the corrugated protrusion 642 to avoid dead corners.

[0035] The reaction zone can be provided with two or more sections, so that the multi-stage reaction zone of polyphosphoric acid and anhydrous hydrogen fluoride can be contacted and reacted step by step, and the reaction can be more gentle, stable, and complete. The polyphosphoric acid flows from the upper part of the reaction zone to the surface of the filler in the reaction zone, and contacts and reacts with the rising anhydrous hydrogen fluoride gas on the reaction zone. In the upper reaction zone, the concentration of polyphosphoric acid is high and the concentration of anhydrous hydrogen fluoride is low, so that the polyphosphoric acid can completely react with the anhydrous hydrogen fluoride gas to form phosphorus oxytrifluoride gas, avoiding excess The anhydrous hydrogen fluoride is lifted to the separation zone together with the generated phosphorus oxyfluoride gas through the upper reaction zone, thereby improving the purity of the phosphorus oxyfluoride gas; in the lower reaction zone, the concentration of polyphosphoric acid is low, but the concentration of anhydrous hydrogen fluoride is high, and the anhydrous hydrogen fluoride in the reaction zone reacts the polyphosphoric acid thoroughly. Therefore, the multi-stage reaction zone uses a step-by-step concentration step-by-step reaction to avoid excess polyphosphoric acid from passing through the reaction zone and the feed zone and remaining at the bottom of the tower body 61, thereby effectively improving the reaction yield between polyphosphoric acid and anhydrous hydrogen fluoride and reducing the occurrence of side reactions. By setting a multi-stage reaction zone, the reaction temperature of the reaction zones in different stages is controlled by the multi-stage shell-and-tube heat exchanger 63, and the temperature control is more accurate. The temperature of the reaction system is accurately controlled to ensure the temperature stability of the reaction system, avoid fluctuations in the reaction temperature of the reaction zone, reduce the occurrence of side reactions in the reaction zone, and achieve step-by-step reaction temperatures in different stages, which can well meet the staged reaction process of polyphosphoric acid and anhydrous hydrogen fluoride, improve the stability of the reaction between polyphosphoric acid and anhydrous hydrogen fluoride, and reduce the occurrence of side reactions.

[0036] In particular, the reaction zone is provided with two sections, wherein the temperature of the lower reaction zone is controlled at 80-100° C. by the shell-and-tube heat exchanger 63, so that the lower reaction zone is in a low-temperature reaction stage, and the high-concentration anhydrous hydrogen fluoride and the low-concentration polyphosphoric acid react at a relatively low temperature to avoid a violent reaction, wherein the temperature of the upper reaction zone is controlled at 100-120° C., so that the upper reaction zone is in a high-temperature reaction stage, and the low-concentration anhydrous hydrogen fluoride and the high-concentration polyphosphoric acid react at a relatively high temperature to improve the reaction power, and at the same time, the rising power of the reaction product phosphorus oxyfluoride can be improved, ensuring that the phosphorus oxyfluoride can be better lifted in the separation zone in the high-temperature reaction zone, reducing the entrainment of phosphorus oxyfluoride by the liquid descending process of polyphosphoric acid toward the bottom of the tower body 61.

[0037] The present invention increases the resistance and path of the rising gas of phosphorus oxyfluoride by using fillers through the upper separation zone, so that the mist of polyphosphoric acid entrained in the rising gas of phosphorus oxyfluoride is accumulated and absorbed through contact with the surface of the fillers and flows back into the reaction zone after sedimentation. Therefore, through the separation zone, the separation of phosphorus oxyfluoride and the entrained polyphosphoric acid mist can be well achieved, thereby improving the purity of the phosphorus oxyfluoride product. In addition, a structural redistributor 65 and a wire mesh demister 66 are arranged on the upper part of the tower body 61, and the phosphorus oxyfluoride entrained in the phosphorus oxyfluoride can be further removed by the wire mesh demister 66, and the captured mist and the generated liquid enter the separation zone through the structural redistributor 65 to achieve gas-liquid separation.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A phosphorus oxyfluoride reaction and separation integrated preparation tower, characterized in that: The tower body (61) comprises a tower body (61), wherein a feed zone, a plurality of reaction zones and a separation zone are sequentially arranged in the tower body (61) from bottom to top, the feed zone and the separation zone inside the tower body (61) are both filled with a packing section (62) filled with a packing, a cyclone distributor (64) is arranged between the feed zone and the reaction zone, between the separation zone and the reaction zone, and between the plurality of reaction zones, wherein a first feed inlet (611) for anhydrous hydrogen fluoride to enter is arranged at the bottom of the packing section (62) in the feed zone, each of the reaction zones is provided with a shell-and-tube heat exchanger (63), a threaded tube (633) for controlling the reaction temperature is arranged on the shell-and-tube heat exchanger (63), and the space between the threaded tubes (633) is also filled with a packing, wherein a first feed inlet (611) for anhydrous hydrogen fluoride to enter is arranged at the bottom of the packing section (62) in the feed zone, and a first feed inlet (611) for anhydrous hydrogen fluoride to enter is arranged at the bottom of the packing section (62) in the feed zone, and a shell-and-tube heat exchanger (63) is arranged on the shell-and-tube heat exchanger (63), wherein a threaded tube (633) for controlling the reaction temperature is arranged on the shell-and-tube heat exchanger (63), and the space between the threaded tubes (633) is also filled with a packing, wherein a first feed inlet (611) for anhydrous hydrogen fluoride to enter is arranged at the bottom of the packing section (62) in the feed zone, and ... A second feed port (612) for feeding polyphosphoric acid is provided at the upper part of the reaction zone of the first layer. The polyphosphoric acid flows from the top reaction zone to the reaction zone of the lower layer in sequence through dispersion. The polyphosphoric acid contacts the anhydrous hydrogen fluoride on the fillers between the threaded tubes (633) dispersed in the reaction zone to form a step-wise reaction of concentration. The reaction temperature of the multiple reaction zones is controlled from the lower part of the tower body (61) to the upper part through the shell-and-tube heat exchanger (63) to be a step-wise reaction temperature of 80-120° C., so that the phosphorus oxyfluoride gas generated after the reaction is fractionated through the filler section (62) on the separation zone and enters the next process at the top product outlet (615) at the top of the tower body (61); The swirl distributor (64) is provided with a plurality of swirl plates (641) arranged in an array along its central circumference, and the swirl plates (641) are arranged at an inclination with an acute angle θ of 30° to 60° between the swirl plates (641) and the bottom surface of the swirl distributor (64); the swirl plates (641) are provided with a plurality of corrugated protrusions (642) arranged in a wavy curve in a vertical direction on both surfaces, and the cross-section of the corrugated protrusions (642) is in a semicircular arc shape; The reaction zone is filled with a saddle-shaped filler. One or more saddle-shaped fillers can be placed inside the spiral of the threaded tube (633) and between the pitches of the upper and lower spirals. When the saddle-shaped fillers are filled inside the spiral of the threaded tube (633) of the shell-and-tube heat exchanger (63), the saddle shape of the saddle-shaped filler is placed in a manner that fits the spiral direction of the threaded tube (633), so that the outer wall surface of the threaded tube (633) fits the saddle shape of the saddle-shaped filler.

2. A phosphorus oxyfluoride reaction and separation integrated preparation tower according to claim 1, characterized in that: The shell-and-tube heat exchanger (63) comprises inlet and outlet main pipes (631) arranged at the upper and lower parts, each of the inlet and outlet main pipes (631) being evenly provided with a plurality of horizontal and vertical branch pipes (632) distributed in length in the axial direction, and a plurality of the threaded pipes (633) being evenly arranged between the corresponding branch pipes (632) at the upper and lower parts.

3. The phosphorus oxyfluoride reaction and separation integrated preparation tower according to claim 1, characterized in that: The reaction zone is divided into two sections, wherein the temperature of the lower reaction zone is controlled at 80-100°C, and the temperature of the upper reaction zone is controlled at 100-120°C.

4. The phosphorus oxyfluoride reaction and separation integrated preparation tower according to claim 1, characterized in that: The inner diameter of the spiral of the threaded tube (633) is 60-150 mm, and the pitch of the spiral is 50-100 mm.

5. The phosphorus oxyfluoride reaction and separation integrated preparation tower according to claim 1, characterized in that: The spiral directions of the threaded tubes (633) of the shell-and-tube heat exchangers (63) between the upper and lower adjacent reaction zones of the multiple reaction zones are arranged in opposite directions.

6. The phosphorus oxyfluoride reaction and separation integrated preparation tower according to claim 1, characterized in that: The tower body (61) is provided with a structural redistributor (65) at the upper portion of the separation zone.

7. The phosphorus oxyfluoride reaction and separation integrated preparation tower according to claim 6, characterized in that: The tower body (61) is provided with a wire mesh demister (66) at an upper portion of the structural redistributor (65).

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