A reaction vessel for the preparation of hydrofluoric acid

Abstract

This utility model belongs to the field of chemical reaction vessel technology, specifically relating to a reaction vessel for the preparation of hydrofluoric acid. It includes an outer shell, an inner shell, a servo motor, and a rotating shaft. The inner shell is located inside the outer shell and has an inlet pipe and an outlet pipe, both of which extend out of the outer shell. The servo motor is located outside the outer shell, and the rotating shaft is located inside the inner shell. The top of the rotating shaft extends through both the inner and outer shells and is connected to the output shaft of the servo motor via a bevel gear transmission pair. Multiple stirring rods are mounted on the rotating shaft, and a crossbeam is fixed to the bottom of the shaft. A stirring frame is located below the crossbeam, and the stirring frame includes two side frames, each rotatably connected to a set of rollers. This device utilizes a composite structure of inner and outer shells to solve corrosion and leakage problems, improving production safety; it can also agitate undissolved solid materials deposited at the bottom of the vessel, reducing solid particle deposition and promoting the normal progress of the reaction.

Description

Technical Field

[0001] This utility model belongs to the field of chemical reaction vessel technology, specifically relating to a reaction vessel for the preparation of hydrofluoric acid. Background Technology

[0002] Hydrofluoric acid is an aqueous solution of hydrogen fluoride gas. It is a clear, colorless, corrosive liquid with a strong, pungent odor. It is a weak acid, but extremely corrosive, capable of corroding metals, glass, and silicon-containing materials such as quartz. Due to its strong corrosiveness, hydrofluoric acid is particularly destructive to glass. Inhalation of hydrofluoric acid vapor or skin contact can cause severe burns and may lead to deep tissue damage, potentially endangering life in severe cases. Currently, hydrofluoric acid is mainly produced industrially by reacting fluorite (whose main component is calcium fluoride) with concentrated sulfuric acid. The chemical reaction is: CaF₂ + H₂SO₄ = CaSO₄ + 2HF.

[0003] However, in the process of preparing hydrofluoric acid, since a solid-liquid mixed reaction is used, the calcium sulfate produced by the reaction will adhere to the surface of the fluorite powder, which will slow down the rapid dissolution of the fluorite powder to a certain extent. This causes some undissolved solid particles to deposit at the bottom of the reactor, and over time, they accumulate more and more, affecting the normal progress of the reaction.

[0004] Therefore, improvements are urgently needed. Utility Model Content

[0005] To address the aforementioned deficiencies in existing technologies, this utility model provides a reaction vessel for the preparation of hydrofluoric acid, comprising an outer shell, an inner shell, a servo motor, and a rotating shaft. The inner shell is disposed inside the outer shell, and a fixing rod is fixedly connected between the inner shell and the outer shell. A feed pipe is disposed at the top of the inner shell, and a discharge pipe is disposed at the bottom of the inner shell, both of which extend out of the outer shell. The servo motor is disposed outside the outer shell, and the rotating shaft is vertically disposed within the inner shell. The top end of the rotating shaft extends out of both the inner and outer shells and is connected to the output shaft of the servo motor via a bevel gear transmission pair. The rotating shaft is sealed and rotatably connected to both the inner and outer shells. A double inert gas-protected mechanical seal is provided at the connection between the inner and outer shells and the rotating shaft, forming a sealed cavity between the two seals. Pressure sensors and HF gas concentration sensors are installed on the sealed cavity. If a slight leak occurs in the first seal, the pressure and HF concentration inside the cavity will immediately increase, triggering the audible and visual alarm system in the control room to provide early warning and facilitate timely intervention and handling by operators, preventing major leakage accidents. The pressure of the introduced inert gas (such as nitrogen) is slightly higher than the pressure inside the vessel, forming a gas seal. Even if there is a minor damage to the sealing surface, it is the inert gas that leaks into the vessel, not the HF gas, that leaks out. Multiple stirring rods are installed on the rotating shaft, and a crossbeam is fixed at the bottom of the rotating shaft. A stirring frame is installed below the crossbeam, and the shape of the stirring frame is adapted to the cross-section of the bottom of the inner shell. The stirring frame includes two side frames on the left and right, and each side frame is rotatably connected to a roller assembly, with the bottom of the roller assembly abutting against the bottom wall of the inner shell.

[0006] Optionally, the outer shell is made of carbon steel, and the inner shell has an inner lining made of Monel alloy or Hastelloy alloy.

[0007] Specifically, the inner lining is made of Monel alloy or Hastelloy alloy plates welded together as a whole, directly contacting the reactants and providing the main corrosion protection barrier.

[0008] Optionally, a silicon carbide filler layer is filled between the outer shell and the inner shell.

[0009] Specifically, the silicon carbide filler layer has good thermal conductivity and chemical stability.

[0010] Optionally, the bevel gear transmission pair includes a meshing horizontal bevel gear and a vertical bevel gear, with the horizontal bevel gear fixed to the outside of the rotating shaft and the vertical bevel gear mounted on the output shaft of the servo motor.

[0011] Optionally, a sealing cap is provided on the feed pipe, a discharge valve is provided on the discharge pipe, and a support leg is provided at the bottom of the outer casing.

[0012] Optionally, the roller assembly includes two rollers, with several S-shaped connecting plates fixedly connected between the two rollers.

[0013] Specifically, the S-shaped connecting plate helps to agitate the material deposited at the bottom of the tank.

[0014] Optionally, a heating jacket is provided on the outside of the outer shell, and a heat exchange coil is provided inside the inner shell. One end of the heat exchange coil is provided with a coil inlet, and the other end is provided with a coil outlet. Both the coil inlet and the coil outlet extend out of the outer shell.

[0015] Specifically, the position of the heat exchange coil will not affect the normal rotation of the stirring rod, crossbeam and frame; temperature sensors are installed on both the outer shell and the inner shell to detect the heating temperature of the outer shell and the inner shell respectively.

[0016] This invention also includes other components that enable the reactor for the preparation of hydrofluoric acid to function normally, all of which are conventional techniques in the art. Furthermore, any devices or components not specified in this invention employ conventional techniques in the art, such as servo motors.

[0017] The working principle of this invention is as follows: concentrated sulfuric acid and fluorite powder are added to the inner shell of the reaction vessel. The servo motor is started to drive the rotating shaft to rotate, which in turn drives the stirring rod and stirring frame to rotate, thus stirring and mixing the materials. At the same time, the heating jacket and heat exchange coil heat the materials to promote the reaction. Due to the rotation of the stirring frame, the roller assembly is driven to roll at the bottom of the inner shell, stirring up the deposited materials to reduce sedimentation and facilitate the normal progress of the reaction.

[0018] The beneficial effects of this utility model are that, through the outer shell, inner shell, servo motor and rotating shaft, the composite structure can solve the corrosion leakage problem and improve the safety of production; through the stirring frame and roller assembly, the undissolved solid materials deposited at the bottom of the reactor can be stirred up, reducing the deposition of solid particles and promoting the normal progress of the reaction. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0021] Figure 2 This is a schematic diagram of the roller assembly of this utility model.

[0022] In the diagram: 1. Outer shell, 2. Inner shell, 3. Servo motor, 4. Rotating shaft, 5. Fixing rod, 6. Feed pipe, 7. Discharge pipe, 8. Bevel gear transmission pair, 9. Stirring rod, 10. Crossbeam, 11. Frame, 12. Roller assembly, 13. Roller, 14. Connecting plate, 15. Silicon carbide packing layer, 16. Heating jacket, 17. Heat exchange coil. Detailed Implementation

[0023] The present invention will now be clearly described with reference to the accompanying drawings and specific embodiments. This description is merely for explaining the present invention and is not intended to limit it. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art based on the embodiments of the present invention without inventive effort to obtain all other embodiments should be included within the protection scope of the present invention.

[0024] Example

[0025] like Figure 1-2 As shown, this embodiment of the present invention provides a reaction vessel for the preparation of hydrofluoric acid, including an outer shell 1, an inner shell 2, a servo motor 3, and a rotating shaft 4. The inner shell 2 is disposed inside the outer shell 1, and a fixing rod 5 is fixedly connected between the inner shell 2 and the outer shell 1. A feed pipe 6 is provided at the top of the inner shell 2, and a discharge pipe 7 is provided at the bottom of the inner shell 2. Both the feed pipe 6 and the discharge pipe 7 extend out of the outer shell 1. A sealing cap is provided on the feed pipe 6, and a discharge valve is provided on the discharge pipe 7. Support legs are provided at the bottom of the outer shell 1. The servo motor 3 is located at... Outside the outer casing 1, a rotating shaft 4 is vertically installed within the inner casing 2. The top end of the rotating shaft 4 extends through the inner casing 2 and the outer casing 1, and is connected to the output shaft of the servo motor 3 via a bevel gear transmission pair 8. The bevel gear transmission pair 8 includes a meshing horizontal bevel gear and a vertical bevel gear. The horizontal bevel gear is fixed outside the rotating shaft 4, and the vertical bevel gear is mounted on the output shaft of the servo motor 3. The rotating shaft 4 is sealed and rotatably connected to both the inner casing 2 and the outer casing 1. The connection points between the inner casing 2, the outer casing 1, and the rotating shaft 4 are equipped with a mechanical system with double inert gas protection. The system is sealed, with two seals forming a sealed cavity. A pressure sensor and an HF gas concentration sensor are installed in this sealed cavity. If the first seal leaks even slightly, the pressure and HF concentration inside the cavity will immediately increase, triggering the audible and visual alarm system in the control room. This provides early warning, allowing operators to intervene and handle the situation promptly, preventing major leaks. The introduced inert gas (such as nitrogen) is introduced at a pressure slightly higher than the pressure inside the vessel, forming a gas seal. Even if there is a minor break in the sealing surface, it is the inert gas that leaks into the vessel, not the HF gas, which leaks outwards. (Spindle 4) Multiple stirring rods 9 are provided on the top, and a crossbeam 10 is fixed at the bottom of the rotating shaft 4. A stirring frame is provided below the crossbeam 10, and the shape of the stirring frame is adapted to the cross section of the bottom of the inner shell 2. The stirring frame includes two side frames 11 arranged on the left and right. Each side frame 11 is rotatably connected to a roller assembly 12, and the bottom of the roller assembly 12 abuts against the bottom wall of the inner shell 2. The roller assembly 12 includes two rollers 13, and several S-shaped connecting plates 14 are fixedly connected between the two rollers 13. The S-shaped connecting plates 14 help to stir the material deposited at the bottom of the tank.

[0026] The outer shell 1 is made of carbon steel, and the inner shell 2 has an inner lining layer. This inner lining layer is integrally welded from Monel alloy sheet and comes into direct contact with the reactants, providing the primary corrosion barrier. A silicon carbide filler layer 15 is filled between the outer shell 1 and the inner shell 2. The silicon carbide filler layer 15 has good thermal conductivity and chemical stability.

[0027] In addition, a heating jacket 16 is provided on the outside of the outer shell 1, and a heat exchange coil 17 is provided inside the inner shell 2. One end of the heat exchange coil 17 is provided with a coil inlet and the other end is provided with a coil outlet. Both the coil inlet and the coil outlet extend out of the outer shell 1. The position of the heat exchange coil 17 will not affect the normal rotation of the stirring rod 9, the crossbeam 10 and the frame 11. Temperature sensors are provided on both the outer shell 1 and the inner shell 2 to detect the heating temperature of the outer shell 1 and the inner shell 2, respectively.

[0028] The working principle of this invention is as follows: concentrated sulfuric acid and fluorite powder are added to the inner shell 2 of the reaction vessel. The servo motor 3 is started to drive the rotating shaft 4 to rotate, which in turn drives the stirring rod 9 and the stirring frame to rotate, thus stirring and mixing the materials. At the same time, the heating jacket 16 and the heat exchange coil 17 heat the materials to promote the reaction. Due to the rotation of the stirring frame, the roller assembly 12 is driven to roll at the bottom of the inner shell 2, stirring up the deposited materials to reduce deposition and facilitate the normal progress of the reaction.

[0029] The embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A reaction vessel for preparing hydrofluoric acid, comprising an outer shell, an inner shell, a servo motor, and a rotating shaft, characterized in that: The inner shell is located inside the outer shell, and a fixing rod is fixedly connected between the inner shell and the outer shell. A feed pipe is provided at the top of the inner shell, and a discharge pipe is provided at the bottom of the inner shell. Both the feed pipe and the discharge pipe extend out of the outer shell. The servo motor is located outside the outer shell. The rotating shaft is vertically installed in the inner shell. The top of the rotating shaft extends out of the inner shell and the outer shell and is connected to the output shaft of the servo motor through a bevel gear transmission pair. The rotating shaft is sealed and rotatably connected to both the inner shell and the outer shell. Multiple stirring rods are provided on the rotating shaft. A crossbeam is fixed at the bottom of the rotating shaft. A stirring frame is provided below the crossbeam. The shape of the stirring frame is adapted to the cross section of the bottom of the inner shell. The stirring frame includes two side frames on the left and right. A roller assembly is rotatably connected to each side frame, and the bottom of the roller assembly abuts against the bottom wall of the inner shell.

2. The reaction vessel for preparing hydrofluoric acid according to claim 1, characterized in that: The outer shell is made of carbon steel, and the inner shell has an inner lining made of Monel alloy or Hastelloy alloy.

3. The reaction vessel for preparing hydrofluoric acid according to claim 2, characterized in that: A silicon carbide filler layer is filled between the outer shell and the inner shell.

4. The reaction vessel for preparing hydrofluoric acid according to claim 3, characterized in that: The bevel gear transmission pair includes a meshing horizontal bevel gear and a vertical bevel gear. The horizontal bevel gear is fixed to the outside of the rotating shaft, and the vertical bevel gear is mounted on the output shaft of the servo motor.

5. The reaction vessel for preparing hydrofluoric acid according to claim 4, characterized in that: The feed pipe is equipped with a sealing cap, the discharge pipe is equipped with a discharge valve, and the outer casing is equipped with support legs.

6. The reaction vessel for preparing hydrofluoric acid according to claim 5, characterized in that: The roller assembly consists of two rollers, with several S-shaped connecting plates fixedly connected between the two rollers.

7. The reaction vessel for preparing hydrofluoric acid according to claim 6, characterized in that: The outer shell is equipped with a heating jacket, and the inner shell is equipped with a heat exchange coil. One end of the heat exchange coil is equipped with a coil inlet, and the other end is equipped with a coil outlet. Both the coil inlet and the coil outlet extend out of the outer shell.

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