A system for efficient preparation of polyphosphoric acid based on phosphorus pentoxide

Abstract

This utility model discloses a system for the efficient preparation of polyphosphoric acid based on phosphorus pentoxide, comprising a phosphoric acid storage tank and a phosphorus pentoxide storage tank. The phosphoric acid storage tank is connected to a polymerization reactor via a first feed pipe, and the phosphorus pentoxide storage tank is connected to the polymerization reactor via a second feed pipe. The bottom of the polymerization reactor is connected to an intermediate storage tank via a first connecting pipe, and the bottom of the intermediate storage tank is connected to a decolorization tank via a second connecting pipe. A hydrogen peroxide storage tank is located above the decolorization tank and is connected to a hydrogen peroxide distributor via a third connecting pipe. A discharge pipe with an anti-clogging mechanism is located at the bottom of the decolorization tank. Exhaust pipes are located at the top of the polymerization reactor, the intermediate storage tank, and the decolorization tank, and a tail gas purification tower is installed at the end of each exhaust pipe. This system not only ensures continuous production of the polymerization and decolorization reactions, shortens production time, and improves production efficiency, but also avoids blockages during the discharge process.

Description

Technical Field

[0001] This utility model belongs to the field of phosphorus chemical production technology, specifically relating to a system for the efficient preparation of polyphosphoric acid based on phosphorus pentoxide. Background Technology

[0002] Polyphosphoric acid, also known as polyphosphate or polyphosphoric acid, is a mixture of inorganic polymers. In the phosphate industry, phosphoric acid with a w(H3PO4) content of 105% or higher is generally referred to as polyphosphoric acid. At room temperature, polyphosphoric acid is a colorless, transparent, syrupy substance; at low temperatures, it is a solid, glassy substance. It becomes fluid when heated to 50–60°C, is hygroscopic, miscible with water, and hydrolyzes to form phosphoric acid; it does not crystallize. Polyphosphoric acid is a protic acid, possessing strong dehydrating ability and some corrosiveness, but it is non-oxidizing. It has wide applications in industries such as pigments, pharmaceuticals, fragrances, leather, and flame retardant manufacturing. Currently, industrial methods for producing polyphosphoric acid include thermal methods, wet methods, and synthetic methods. The thermal method involves the direct combustion of phosphoric acid to produce phosphoric acid, which is then concentrated through high-temperature heating to produce polyphosphoric acid. This method produces products with fewer impurities and higher quality, but it has high energy consumption and production costs. The wet process uses wet-process phosphoric acid as raw material, which is concentrated and then polymerized by adding phosphorus pentoxide. This method has low cost and low energy consumption, but the product contains more impurities. The synthetic method uses phosphoric acid and phosphorus pentoxide as raw materials, and prepares the product through heating polymerization and purification processes. This method has a short process flow, simple operation, and low pollution, and is currently the mainstream industrial production method. In existing technologies, the equipment for polymerizing polyphosphoric acid using phosphorus pentoxide as raw material is mainly a stirred tank with a stirrer. During use, phosphoric acid and phosphorus pentoxide are added to the polymerization tank, and... The agitator stirs the reaction of polyphosphoric acid and phosphorus pentoxide. After stirring, hydrogen peroxide is added to the stirred tank for decolorization to obtain polyphosphoric acid. However, this method has the following drawbacks: First, the polymerization of phosphorus pentoxide and phosphoric acid, as well as the decolorization with hydrogen peroxide, all take place in the same stirred tank, prolonging the production time and reducing efficiency. Second, the direct decolorization with hydrogen peroxide in the stirred tank leads to blockage at the discharge port due to the relatively poor flowability of the polyphosphoric acid. Therefore, developing a high-efficiency polyphosphoric acid preparation system based on phosphorus pentoxide that has a reasonable structural layout, improves production efficiency, and avoids discharge blockage is essential. Summary of the Invention

[0003] The purpose of this invention is to provide a high-efficiency polyphosphoric acid preparation system based on phosphorus pentoxide that has a reasonable structural layout, which can improve production efficiency and avoid material blockage.

[0004] The purpose of this utility model is achieved as follows: It includes a phosphoric acid storage tank and a phosphorus pentoxide storage tank. The phosphoric acid storage tank is connected to a polymerization reactor via a first feed pipe. A first metering pump and a first control valve are sequentially installed on the first feed pipe. The phosphorus pentoxide storage tank is connected to the top of the polymerization reactor via a second feed pipe. The phosphorus pentoxide storage tank is equipped with a weighing sensor. A second control valve is installed on the second feed pipe. The bottom of the polymerization reactor is connected to an intermediate storage tank via a first connecting pipe. The bottom of the intermediate storage tank is connected to a decolorization tank via a second connecting pipe. Both the first and second connecting pipes are equipped with conveying pumps. Agitators are installed in the polymerization reactor and intermediate storage tank, and a hydrogen peroxide storage tank is installed above the decolorization tank. A hydrogen peroxide distributor is installed at the top of the decolorization tank, and an agitator connected to the hydrogen peroxide distributor is installed at the bottom of the decolorization tank. The hydrogen peroxide storage tank is connected to the hydrogen peroxide distributor through a third feed pipe. A second metering pump and a third control valve are installed sequentially on the third feed pipe. A discharge pipe is installed at the bottom of the decolorization tank, and a discharge anti-blocking mechanism is installed on the discharge pipe. An exhaust pipe is installed at the top of the polymerization reactor, intermediate storage tank, and decolorization tank, and a tail gas purification tower is installed at the end of the exhaust pipe.

[0005] Compared with existing technologies, the advantages of this device are as follows: First, this system sets up an intermediate storage tank and a decolorization tank at the rear end of the polymerization reactor, separating the polymerization and decolorization processes. The intermediate storage tank acts as a connection between the polymerization reactor and the decolorization tank. While the polyphosphoric acid in the decolorization tank is undergoing decolorization, the polyphosphoric acid produced by the polymerization reaction in the polymerization reactor can be stored in the intermediate storage tank. After the polyphosphoric acid in the decolorization tank has been decolorized, the polyphosphoric acid in the intermediate storage tank is then transferred to the decolorization tank. The decolorization tank is located at the rear end of the polymerization reactor. The connection between the reactor and the decolorization tank ensures continuous production of both polymerization and decolorization reactions, thus shortening production time and improving efficiency. Secondly, an anti-blocking mechanism is installed on the discharge pipe of the decolorization tank. This mechanism guides the discharge of polyphosphoric acid, allowing it to flow quickly and smoothly from the tank, preventing blockages and ensuring stable and efficient system operation. This device boasts advantages such as reasonable structural layout, high production efficiency, and stable operation, making it easy to promote and use. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0007] Figure 2 This is a schematic diagram of the decolorizing tank 9 in this utility model;

[0008] In the diagram: 1-Phosphoric acid storage tank, 2-Phosphorus pentoxide storage tank, 3-First feed pipe, 4-Polymerization reactor, 5-Second feed pipe, 6-First connecting pipe, 7-Intermediate storage tank, 8-Second connecting pipe, 9-Decolorization tank, 91-Discharge pipe, 92-Rotary joint, 93-Main liquid inlet pipe, 94-Distribution branch pipe, 95-Sealing plate, 96-Nozzle, 97-Drive motor, 98-Driving gear, 99-Driven gear, 910-Central shaft, 911-Upper stirring rod 912-Intermediate stirring shaft, 913-Lower stirring rod, 914-Support frame, 915-Support rod, 916-Side scraper, 917-Bottom scraper, 918-Helical blade, 919-Stirring blade, 920-Lifting cylinder, 921-Modible sealing plug, 922-Bracket, 923-Discharge pipe, 924-Pressure pipe, 925-Air compressor, 10-Third feed pipe, 11-Hydrogen peroxide storage tank, 12-Exhaust pipe, 13-Tail gas purification tower. Detailed Implementation

[0009] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0010] like Figures 1-2As shown, this utility model includes a phosphoric acid storage tank 1 and a phosphorus pentoxide storage tank 2. The phosphoric acid storage tank 1 is used to store phosphoric acid raw materials for producing polyphosphoric acid. The phosphoric acid storage tank 1 is a device used in the prior art, equipped with corresponding inlets, level gauges, and other structural components. The phosphorus pentoxide storage tank 2 is used to store phosphorus pentoxide, the raw material for producing polyphosphoric acid, and is equipped with corresponding inlets, a metering feeder, and other components. The phosphoric acid storage tank 1 is connected to a polymerization reactor 4 through a first feed pipe 3. A first metering pump and a first control valve are sequentially installed on the first feed pipe 3. The phosphorus pentoxide storage tank 2 is connected to the top of the polymerization reactor 4 through a second feed pipe 5. The polymerization reactor 4 adopts the structure used in the prior art. The polymerization reactor 4 is equipped with components such as a safety valve and a heating element. A weighing sensor is installed on the phosphorus pentoxide storage tank 2. This weighing sensor is a structure used in the prior art; finished products are directly purchased according to usage requirements. It is used to weigh the phosphorus pentoxide in the phosphorus pentoxide storage tank 2, facilitating the addition of phosphorus pentoxide to the polymerization reactor 4. A second control valve is installed on the second feed pipe 5. The bottom of the polymerization reactor 4 is connected to an intermediate storage tank 7 via a first connecting pipe 6. The bottom of the intermediate storage tank 7 is connected to a decolorizing tank 9 via a second connecting pipe 8. Both the first connecting pipe 6 and the second connecting pipe 8 are equipped with... The polymerization reactor 4 and intermediate storage tank 7 are equipped with a pump and a connecting valve. Agitators are installed in both the polymerization reactor 4 and intermediate storage tank 7. The top of the decolorizing tank 9 is connected to a hydrogen peroxide storage tank 11 via a third feed pipe 10. A second metering pump and a third control valve are sequentially installed on the third feed pipe 10. The polymerization reactor 4 and intermediate storage tank 7 are equipped with agitators. The hydrogen peroxide storage tank 11 is located above the decolorizing tank 9. A hydrogen peroxide distributor is installed at the top of the decolorizing tank 9. A stirring mechanism connected to the hydrogen peroxide distributor is located at the bottom of the decolorizing tank 9. The hydrogen peroxide storage tank 11 is connected to the hydrogen peroxide distributor via the third feed pipe 10. A second metering pump and a third control valve are sequentially installed on the third feed pipe 10. The system has a second metering pump and a second control valve. The top of the system is connected to the bottom of the decolorizing tank 9 via a third feed pipe 10. A discharge pipe 91 is provided on the bottom of the discharge pipe 91. The discharge pipe 91 is equipped with a discharge anti-blocking mechanism. The anti-blocking discharge mechanism can guide the discharge of polyphosphoric acid from the decolorizing tank 9 during discharge, so that the polyphosphoric acid can be discharged quickly and smoothly from the decolorizing tank 9, avoiding blockage during the discharge process and ensuring stable and efficient operation of the system. A tail gas purification tower 13 is installed at the end of the exhaust pipe 12. The tail gas purification tower 13 is used to purify the tail gas generated during the polymerization reaction to avoid environmental pollution. The tail gas purification tower adopts a wet treatment process technology.

[0011] The system operates as follows: First, the first metering pump and first control valve on the first feed pipe 3 are opened to quantitatively add phosphoric acid from the phosphoric acid storage tank 1 into the polymerization reactor 4. Then, the first metering pump and first control valve are closed, and the stirrer inside the polymerization reactor 4 is turned on to agitate the phosphoric acid. Next, the second control valve on the second feed pipe is opened, and phosphorus pentoxide from the phosphorus pentoxide storage tank 2 is added to the polymerization reactor 4 using a weighing sensor. Finally, the second control valve is closed, and the stirrer agitates the phosphorus pentoxide and phosphoric acid within the polymerization reactor 4. Phosphorus pentoxide and phosphoric acid react to produce polyphosphoric acid after stirring. After the reaction is complete, the transfer pump and connecting valve on the first connecting pipe 6 are opened, and the polyphosphoric acid in the polymerization reactor 4 enters the intermediate storage tank 7. After all the polyphosphoric acid in the polymerization reactor 4 has entered the intermediate storage tank 7, the transfer pump and connecting valve on the first connecting pipe 6 are closed. Phosphoric acid and phosphorus pentoxide are added to the polymerization reactor 4 again according to the above method to carry out the polymerization reaction. The polyphosphoric acid is stored in the intermediate storage tank 7 and can be stirred using a stirrer. When decolorization treatment of polyphosphoric acid is required... At this time, the delivery pump and connecting valve on the second connecting pipe 8 are opened to transport the polyphosphoric acid in the intermediate storage tank 7 to the decolorizing tank 9 through the second connecting pipe 8. After the polyphosphoric acid enters the decolorizing tank 9, the delivery pump and connecting valve on the second connecting pipe 8 are closed. Then, the second metering pump and the third control valve on the third feed pipe 10 are opened to transport the hydrogen peroxide in the hydrogen peroxide storage tank 11 to the hydrogen peroxide distributor through the third feed pipe 10. The hydrogen peroxide is then evenly added to the decolorizing tank 9 using the hydrogen peroxide distributor. After the hydrogen peroxide enters the decolorizing tank 9, the third feed pipe 10 is closed. The second metering pump and the third control valve on the 0, after being stirred by the stirring mechanism, allow hydrogen peroxide to be fully mixed with polyphosphoric acid. During the mixing process, the polyphosphoric acid can be decolorized. After the polyphosphoric acid decolorization is completed, the polyphosphoric acid in the decolorization tank 9 can be discharged through the discharge pipe 91 under the action of the discharge anti-blocking mechanism. The decolorization tank 9 is also equipped with a heating component to heat the polyphosphoric acid. After the polyphosphoric acid in the decolorization tank 9 is discharged, the polyphosphoric acid in the intermediate storage tank 7 can be sent back into the decolorization tank 9 for a second decolorization treatment. This system has an intermediate storage tank 7 and a decolorizing tank 9 at the rear end of the polymerization reactor to separate the polymerization and decolorization processes. The intermediate storage tank 7 connects the polymerization reactor 4 and the decolorizing tank 9. While the polyphosphoric acid in the decolorizing tank 9 is undergoing decolorization, the phosphoric acid produced by the polymerization reaction in the polymerization reactor 4 can be stored in the intermediate storage tank 7. After the polyphosphoric acid in the decolorizing tank 9 has finished decolorizing, the polyphosphoric acid in the intermediate storage tank 7 is then sent to the decolorizing tank 9. The decolorizing tank 9 is located between the polymerization reactor 4 and the decolorizing tank 9, which ensures the continuity of the polymerization and decolorization processes, thus shortening the production time and effectively improving production efficiency.

[0012] To ensure uniform distribution of hydrogen peroxide within the decolorization tank 9 and even mixing of the hydrogen peroxide with polyphosphoric acid, the hydrogen peroxide distributor includes a rotary joint 92, a main inlet pipe 93, and distribution branch pipes 94. The main inlet pipe 93 is rotatably mounted through the top of the decolorization tank 9, with its upper end rotatably connected to the lower end of the rotary joint 92. The upper end of the rotary joint 92 is connected to the third feed pipe 10. A sealing plate 95 is installed at the lower end of the main inlet pipe 93. The distribution branch pipes 94 are evenly distributed... A nozzle 96 is installed at the end of the distribution branch pipe 94 located in the decolorization tank 9, and a drive motor 97 is installed above the decolorization tank 9. The drive motor 97 is a structure used in the prior art, and a ready-made product can be purchased directly according to the power required. A drive gear 98 is installed on the output shaft of the drive motor 97, and a driven gear 99 is installed on the outer wall of the inlet main pipe 93. The drive gear 98 and the driven gear 99 mesh with each other to add hydrogen peroxide into the decolorization tank 9. When water is being supplied, the drive motor 97 is turned on. The drive motor 97 drives the drive gear 98 to rotate, which in turn drives the driven gear 99 to rotate. During the rotation of the driven gear 99, the main inlet pipe 93 is rotated. When hydrogen peroxide flows out from the third inlet pipe 10, it first enters the rotary joint 92, then enters the rotating main inlet pipe 93, and then enters each distribution branch pipe 94. Finally, it is evenly sprayed into the decolorization tank 9 through the rotating nozzle 96. The rotation of the multiple distribution branch pipes 94... The hydrogen peroxide is evenly distributed in the decolorization tank 9. Preferably, in order to ensure that the hydrogen peroxide can enter each distribution branch pipe 94 evenly from the main inlet pipe 93 and prevent the hydrogen peroxide from flowing back, the distribution branch pipe 94 includes an inclined section and a horizontal section. The higher end of the inclined section is connected to the main inlet pipe 93, and the lower end of the inclined section is connected to the horizontal section. The nozzle 96 is installed at the other end of the horizontal section. The hydrogen peroxide flows from the higher end of the inclined section to the lower end, which can avoid the problem of hydrogen peroxide backflow.

[0013] Furthermore, to achieve efficient mixing of hydrogen peroxide and polyphosphoric acid and further improve the decolorization effect of polyphosphoric acid, the stirring mechanism includes a central shaft 910, an upper stirring rod 911, a middle stirring rod 912, and a lower stirring rod 913. The upper end of the central shaft 910 is connected to a hydrogen peroxide distributor, and the upper end of the central shaft 910 is fixedly connected to a sealing plate at the bottom of the liquid inlet main pipe 93. The lower end of the central shaft 910 is rotatably mounted at the bottom of the decolorization tank 9 via a support frame 914. There are multiple upper stirring rods 911, middle stirring rods 912, and lower stirring rods 913. The upper stirring rod 911, the middle stirring rod 912, and the lower stirring rod 913 are evenly distributed on the central shaft 910 from top to bottom, and their positions on the central shaft 910 correspond vertically. Side scrapers 916, which slide in contact with the inner wall of the decolorizing tank 9, are installed at the ends of the upper stirring rod 911, the middle stirring rod 912, and the lower stirring rod 913 located on the same side. The bottom of each lower stirring rod 913 is connected to a bottom scraper 917, which slides in contact with the bottom of the decolorizing tank 9, via a support rod 915. Spiral blades 918 are installed on the central shaft 910 below the lower stirring rods 913, and the main inlet pipe 93 rotates. When the central shaft 910 rotates synchronously, it drives the upper stirring rod 911, the middle stirring rod 912, the lower stirring rod 913, the side scraper 916, the support rod 915, the bottom scraper 917, and the spiral blade 918 to rotate synchronously. This synchronous rotation of the upper stirring rod 911, the middle stirring rod 912, the lower stirring rod 913, the side scraper 916, the support rod 915, the bottom scraper 917, and the spiral blade 918 ensures comprehensive stirring of the hydrogen peroxide and polyphosphoric acid within the decolorization tank 9. Simultaneously, the side scraper 916 scrapes the side walls of the decolorization tank 9. The bottom scraper 917 can scrape the bottom of the decolorizing tank 9 to prevent sticking. Preferably, in order to enhance the mixing effect, multiple sets of stirring blades 919 are installed at equal intervals along the axial direction on the intermediate stirring rod 912. Each set of stirring blades 919 consists of two blades, which are symmetrically installed on the intermediate stirring rod 912. The stirring blades 919 and the intermediate stirring rod 912 are arranged perpendicularly. The stirring blades 919 have a fan-shaped structure. The intermediate stirring rod 912 performs horizontal stirring, and the stirring blades 919 perform vertical stirring, which can significantly improve the mixing effect.

[0014] Furthermore, the discharge anti-blocking mechanism includes a lifting cylinder 920 and a movable sealing plug 921. The lifting cylinder 920 is a structure used in the prior art, and a finished product can be directly purchased according to the required stroke size. A base plate is installed at the bottom of the discharge pipe 91, and a bracket 922 is installed below the discharge pipe 91. The fixed end of the lifting cylinder 920 is installed on the bracket 922, and the movable end of the lifting cylinder 920 passes through the base plate and is located inside the discharge pipe 91. The movable sealing plug 921 is slidably installed inside the discharge pipe 91 and is fixedly connected to the movable end of the lifting cylinder 920. A discharge pipe 923 is installed on one side of the discharge pipe 91. A first discharge valve and a second discharge valve are sequentially installed on the 3rd discharge tank. A pressure pipe 924 is provided on the discharge pipe 923 between the first discharge valve and the second discharge valve. An air compressor 925 is provided on the pressure pipe 924. The air compressor 925 is mounted on the bracket 922 via a connecting plate. When the polyphosphoric acid in the decolorizing tank 9 is decolorized, the lifting cylinder 920 can drive the movable sealing plug 921 to move upward to seal the upper port of the discharge pipe 91. When the polyphosphoric acid in the decolorizing tank 9 needs to be unloaded, the lifting cylinder 920 controls the movable sealing plug 921 to move downward to below the discharge pipe 923, and then opens the first discharge valve on the discharge pipe 923. After the polyphosphate in the decolorizing tank 9 enters the discharge pipe 91, it is automatically discharged through the discharge pipe 923. When the polyphosphate in the discharge pipe 91 becomes blocked, the second cylinder 920 is controlled again to drive the movable sealing plug 921 upward. The upward movement of the movable sealing plug 921 can clear the polyphosphate blockage in the discharge pipe 91. After clearing, the lifting cylinder 920 controls the movable sealing plug 921 to move down to the lower side of the discharge pipe 923, and the polyphosphate in the discharge pipe 91 is discharged through the discharge pipe 923 again. When the discharge pipe 923 becomes blocked, the first discharge valve and the second discharge valve are closed, so that the discharge pipe 923 is open. In a sealed state, the air compressor 925 is started and put into operation, supplying gas to the discharge pipe through the pressurization pipe 924. Since the sealed volume of the discharge pipe 923 remains unchanged, the pressure increases. At this time, the second discharge valve is opened, and polyphosphoric acid is discharged under atmospheric pressure. After the polyphosphoric acid is discharged, the first discharge valve is opened to continue discharging. In order to facilitate the rapid entry of polyphosphoric acid in the discharge pipe 91 into the discharge pipe 923, the upper surface of the movable sealing plug 921 is set as an inclined surface structure. The inlet of the discharge pipe 923 is located on the lower side of the inclined surface. After being guided by the inclined surface, the polyphosphoric acid can quickly enter the discharge pipe 923.

Claims

1. A system for efficient preparation of polyphosphoric acid based on phosphorus pentoxide comprising a phosphoric acid storage tank (1) and a phosphorus pentoxide storage tank (2), characterized in that: The phosphoric acid storage tank (1) is connected to the polymerization reactor (4) via a first feed pipe (3). A first metering pump and a first control valve are installed sequentially on the first feed pipe (3). The phosphorus pentoxide storage tank (2) is connected to the top of the polymerization reactor (4) via a second feed pipe (5). A weighing sensor is installed on the phosphorus pentoxide storage tank (2). A second control valve is installed on the second feed pipe (5). The bottom of the polymerization reactor (4) is connected to an intermediate storage tank (7) via a first connecting pipe (6). The bottom of the intermediate storage tank (7) is connected to a decolorization tank (9) via a second connecting pipe (8). A delivery pump and a connecting valve are installed on both the first connecting pipe (6) and the second connecting pipe (8). The polymerization reactor (4) and the intermediate storage tank... (7) Each of them is equipped with a stirrer. A hydrogen peroxide storage tank (11) is set above the decolorizing tank (9). A hydrogen peroxide distributor is set at the top of the decolorizing tank (9). A stirring mechanism connected to the hydrogen peroxide distributor is set at the bottom of the decolorizing tank (9). The hydrogen peroxide storage tank (11) is connected to the hydrogen peroxide distributor through a third feed pipe (10). A second metering pump and a third control valve are installed on the third feed pipe (10) in sequence. A discharge pipe (91) is set at the bottom of the decolorizing tank (9). A discharge anti-blocking mechanism is set on the discharge pipe (91). An exhaust pipe (12) is set at the top of the polymerization reactor (4), the intermediate storage tank (7) and the decolorizing tank (9). A tail gas purification tower (13) is installed at the end of the exhaust pipe (12).

2. A system for efficient preparation of polyphosphoric acid based on phosphorus pentoxide according to claim 1, characterized by: The hydrogen peroxide distributor includes a rotary joint (92), a main inlet pipe (93), and distribution branches (94). The main inlet pipe (93) is rotatably disposed through the top of the decolorizing tank (9). The upper end of the main inlet pipe (93) is rotatably connected to the lower end of the rotary joint (92). The upper end of the rotary joint (92) is connected to the third feed pipe (10). A sealing plate (95) is installed at the lower end of the main inlet pipe (93). The distribution branches (94) are evenly distributed and installed in the lower part of the main inlet pipe (93) located inside the decolorizing tank (9). A nozzle (96) is installed at the end of the distribution branches (94). A drive motor (97) is installed above the decolorizing tank (9). A drive gear (98) is installed on the output shaft of the drive motor (97). A driven gear (99) is installed on the outer wall of the main inlet pipe (93). The drive gear (98) and the driven gear (99) mesh with each other.

3. A system for efficient preparation of polyphosphoric acid based on phosphorus pentoxide according to claim 2, characterized by: The distribution branch pipe (94) includes an inclined section and a horizontal section. The higher end of the inclined section is connected to the liquid inlet main pipe (93), and the lower end of the inclined section is connected to the horizontal section. The nozzle (96) is installed at the other end of the horizontal section.

4. The system for efficient preparation of polyphosphoric acid based on phosphorus pentoxide according to claim 1, characterized by: The stirring mechanism includes a central shaft (910), an upper stirring rod (911), a middle stirring rod (912), and a lower stirring rod (913). The upper end of the central shaft (910) is connected to a hydrogen peroxide distributor, and the lower end of the central shaft (910) is rotatably mounted at the bottom of the decolorization tank (9) via a support frame (914). There are multiple upper stirring rods (911), middle stirring rods (912), and lower stirring rods (913), which are evenly distributed from top to bottom on the central shaft (910). The upper stirring rod (911), the middle stirring rod (912), and the lower stirring rod (913) are positioned vertically on the central shaft (910). The upper stirring rod (911), the middle stirring rod (912), and the lower stirring rod (913) located on the same side are equipped with side scrapers (916) that slide in contact with the inner wall of the decolorizing tank (9). The bottom of each lower stirring rod (913) is connected to a bottom scraper (917) that slides in contact with the bottom of the decolorizing tank (9) via a support rod (915). Spiral blades (918) are installed on the central shaft (910) below the lower stirring rod (913).

5. The system for efficiently preparing polyphosphoric acid based on phosphorus pentoxide according to claim 4, characterized in that: Multiple sets of stirring blades (919) are installed at equal intervals along the axial direction on the intermediate stirring rod (912). Each set of stirring blades (919) consists of two blades, which are symmetrically installed on the intermediate stirring rod (912). The stirring blades (919) are arranged perpendicular to the intermediate stirring rod (912) and have a fan-shaped structure.

6. The system for efficiently preparing polyphosphoric acid based on phosphorus pentoxide according to claim 1, characterized in that: The discharge anti-blocking mechanism includes a lifting cylinder (920) and a movable sealing plug (921). A base plate is installed at the bottom of the discharge pipe (91), and a bracket (922) is installed below the discharge pipe (91). The fixed end of the lifting cylinder (920) is installed on the bracket (922), and the movable end of the lifting cylinder (920) passes through the base plate and is located inside the discharge pipe (91). The movable sealing plug (921) is slidably installed inside the discharge pipe (91) and is in contact with the lifting cylinder. The movable end of the cylinder (920) is fixedly connected. A discharge pipe (923) is installed on one side of the discharge pipe (91). A first discharge valve and a second discharge valve are installed in sequence on the discharge pipe (923). A pressurizing pipe (924) is provided on the discharge pipe (923) between the first discharge valve and the second discharge valve. An air compressor (925) is provided on the pressurizing pipe (924). The air compressor (925) is installed on the bracket (922) through a connecting plate.

7. The system for efficiently preparing polyphosphoric acid based on phosphorus pentoxide according to claim 6, characterized in that: The upper surface of the movable sealing plug (921) is configured as an inclined surface, and the inlet of the discharge pipe (923) is located on the lower side of the inclined surface.

Images