A reaction kettle for PBO prepolymer preparation

Abstract

The utility model discloses a reaction kettle for PBO prepolymer preparation relates to reaction kettle agitator technical field, the utility model discloses a kettle body with the feeding port of upper part, the discharge port of lower end and the anchor frame of anchor frame connection in the kettle body and drive mechanism, the lower part of kettle body cavity has at least one part of the stirring belt that is inclined in the up-down direction and is fixed on the anchor frame, a group of through -holes are arranged on the stirring belt. The utility model discloses set up the stirring belt of helical shape on the anchor frame, can take the material upward when rotating, make the material concentrate in the direction close to kettle wall, can improve the uniformity of material dispersion;The utility model discloses that the through -hole of interlaced is set up on each stirring belt straight tube part, when the stirring belt high -speed rotates in the material, the fluid material that flows through the through -hole generates high -speed jet and pressure pulsation because of the cross section abrupt change, and the jet will induce the local high -intensity micro -eddy current behind the stirring belt, and the phenomenon of avoiding the appearance powder mass block residual is carried out to the crushing of powder mass material.

Description

Technical Field

[0001] This utility model relates to a reaction vessel for the preparation of PBO prepolymer, and is situated in the field of reaction vessel agitator technology. Background Technology

[0002] The raw materials for PBO polymerization typically include polyphosphoric acid as a solvent, 4,6-diaminoresorcinol hydrochloride as a monomer, terephthalic acid, and phosphorus pentoxide as a desiccant. Polyphosphoric acid has a honey-like viscous consistency at room temperature and retains a high kinematic viscosity even when heated to 50°C. Terephthalic acid, due to its small particle size (less than 10 micrometers), has poor solubility in polyphosphoric acid, making dispersion difficult and prone to agglomeration. The dissolution of phosphorus pentoxide in polyphosphoric acid significantly increases its kinematic viscosity. For these reasons, PBO prepolymerization is characterized by high system viscosity and difficulty in dispersion.

[0003] Traditional PBO prepolymer reactors typically rely on rapid stirring with a ribbon impeller to achieve uniform dispersion. However, at high viscosity stages, traditional agitators struggle to provide sufficient axial and radial circulation, easily creating mixing dead zones. This leads to uneven reaction, localized overheating, or gelation, resulting in slow material turnover in the reactor's center and slow material exchange between upper and lower or inner and outer layers. Undispersed powder clumps, typically phosphorus pentoxide clumps mixed with small amounts of terephthalic acid, are highly likely to form during the reaction. The presence of these clumps not only affects the monomer ratio, leading to uncontrollable polymerization degrees, but can also cause blockages in the feed pump gears, high pressure in the filter pipes, and even contamination of the spinneret, severely impacting PBO spinning and performance. In practical applications, the single ribbon structure in a conical reactor bottom high-viscosity system has limited ability to break up initial powder clumps, especially P2O5 clumps. These undispersed hard clumps persist, severely affecting the accuracy of monomer stoichiometry, leading to a wider molecular weight distribution, and ultimately impacting product performance. High-viscosity materials are prone to forming static retention layers on the reactor wall and bottom. This not only easily forms new gel agglomerates, but also severely reduces the heat transfer efficiency of the reactor wall, making it difficult to accurately control the reaction temperature and becoming an important factor in process instability. Utility Model Content

[0004] The purpose of this invention is to design a reaction vessel for the preparation of PBO prepolymer that can improve the crushing effect of material agglomerates.

[0005] This utility model includes a vessel body with a feeding port at the top and a discharge port at the bottom, and an anchor frame connected to a drive mechanism inside the vessel body. The lower part of the vessel body cavity has at least a portion of an inclined stirring belt fixed on the anchor frame, and a set of through holes is provided on the stirring belt.

[0006] Furthermore, the stirring belt is at least one spiral belt wound around the anchor frame.

[0007] Furthermore, the stirring band is wavy.

[0008] Furthermore, the lower part of the mixing belt is connected to the lower part of the anchor frame via an inclined surface.

[0009] Furthermore, at least two mixing belts are wound at intervals on the anchor frame, with the lower part of each mixing belt being evenly or unevenly distributed along the circumference.

[0010] Furthermore, a mounting plate with a through hole is provided at the discharge port at the lower end of the vessel body. An annular component containing a bearing is installed inside the through hole. The annular component is fixedly connected to the mounting plate through a connecting part on its outer circumference. The lower end of the support rod, which is fixedly connected to the lower end of the anchor frame at its upper end, is connected to the bearing.

[0011] Furthermore, the support rod is inverted conical in shape.

[0012] This invention features a spiral-shaped stirring belt mounted on an anchor frame. When rotating, it lifts the material upwards, concentrating it near the vessel wall and improving the uniformity of material dispersion. The straight sections of each stirring belt have staggered through-holes. When the stirring belt rotates at high speed through the material, the fluid flowing through the through-holes generates high-speed jets and pressure pulsations due to the abrupt change in cross-sectional area. These jets induce localized high-intensity micro-vortices behind the stirring belt, forming numerous "micro-shear pumps." These micro-vortices can act on gel clumps and P2O5 powder clumps attached to the surface of the stirring belt or suspended in the liquid phase, breaking them up using their high-frequency pulsating shear force, thus preventing powder clump residue.

[0013] The stirring belt in this invention is wavy. The undulations on the surface of the stirring belt cause the material flow path to exhibit an unstable state of up-and-down floating, which disrupts the circular motion of the material at a fixed height and improves the material renewal efficiency in the vertical direction. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the main structure of an embodiment of the present utility model; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 for Figure 1 A magnified view of a section at point B in the middle; Figure 4 for Figure 1 Top view of the middle anchor frame section; Figure 5 for Figure 1 Top view of the mounting plate section; Among them, 1. vessel body, 2. feeding port, 3. stirring motor, 4. reducer, 5. drive shaft, 6. anchor frame, 7. stirring belt, 8. through hole, 9. mounting plate, 10. support rod, 11. discharge channel, 12. gear pump, 13. viewing window and hand hole, 14. ring-shaped component. Detailed Implementation

[0015] by Figure 1 Define the up, down, left, right, front, and back directions in this embodiment.

[0016] As shown in the figure, this embodiment includes a vessel body 1. The upper end of the vessel body 1 is an openable and closable vessel lid structure for easy maintenance, and a feeding port 2 is provided on its upper part. The lower part of the vessel body 1 is conical, and a discharge port is provided at its lower end for discharging the material inside the vessel body 1.

[0017] An anchor frame 6 is installed inside the vessel body 1 via a drive mechanism. The drive mechanism includes a stirring motor 3 mounted above the vessel body 1. A reducer 4 is fixedly connected to the vessel body 1 at the lower end of the stirring motor 3. A drive shaft 5 extending into the inner cavity of the vessel body 1 is located at the lower end of the reducer 4. The drive shaft 5 is fixedly connected to the anchor frame 6 via bolts. In use, starting the stirring motor 3 controls the rotation of the anchor frame 6. In this embodiment, the anchor frame 6 is a four-cross support structure without a central axis. Its lower part is bent, matching the shape of the vessel body 1. During rotation, this prevents material from climbing along the central axis. A stirring belt 7 is provided in the lower part of the inner cavity of the vessel body 1. The stirring belt 7 is a spiral belt that is inclined and wound around the outer periphery of the anchor frame 6 in the vertical direction. It is fixed by welding. When rotating, it can drive the material upward, that is, the material is concentrated in the direction close to the vessel wall, which improves the uniformity of material dispersion. The lower part of the stirring belt 7 is wound along the lower conical structure of the anchor frame 6 and connected to the lower part of the anchor frame 6 through the inclined surface. It is evenly distributed around the circumference of the anchor frame 6, which can stir the lower conical part of the vessel body 1 and avoid the formation of stirring dead corners.

[0018] In this embodiment, two stirring belts 7 are wound at intervals around the outer periphery of the anchor frame 6. Each stirring belt 7 has a set of through holes 8 on the straight part of the anchor frame 6. The through holes 8 are staggered. When the stirring belts 7 rotate at high speed in the material, the fluid material flowing through the through holes 8 generates high-speed jets and pressure pulsations due to the sudden change in cross-sectional area. The jets induce local high-intensity micro-vortices behind the stirring belts 7, forming numerous "micro-shear pumps". The micro-vortices can act on gel clumps and P2O5 powder clumps attached to the surface of the stirring belts 7 or suspended in the liquid phase, breaking them up with their high-frequency pulsating shear force, thus avoiding the phenomenon of powder clump residue.

[0019] The stirring belt 7 with through holes 8 is wavy. When stirring materials, the undulations of the wavy surface of the stirring belt 7 make the flow path of the materials exhibit an unstable state of up-and-down floating, which disrupts the circular motion of the materials at a fixed height and improves the material renewal efficiency in the vertical direction.

[0020] A mounting plate 9 is provided at the discharge port at the lower end of the vessel body 1. A through hole is opened in the middle of the mounting plate 9, and an annular component 14 for mounting a bearing is installed in the through hole. Connecting parts are provided at the front and rear ends of the outer circumference of the annular component 14, which are fixedly connected to the mounting plate 9 through the connecting parts. A discharge channel 11 is formed between the annular component 14 and the mounting plate 9 to facilitate material discharge. A support rod 10 is provided above the annular component 14. The upper end of the support rod 10 is fixedly connected to the anchor frame 6 through a connector, and can rotate with the anchor frame 6. The lower end of the support rod 10 is connected to the bearing on the annular component 14, which can prevent the anchor frame 6 from shaking during use. In this embodiment, the support rod 10 is inverted conical in shape, which can avoid obstructing the discharge port of the vessel body 1. A gear pump 12 is fixedly installed at the lower end of the mounting plate by bolts. The inlet of the gear pump 12 is connected to the discharge port of the vessel body 1, which can accelerate the discharge of the vessel body 1. In this embodiment, sealing ring structures are provided at the connection between the mounting plate 9 and the vessel body 1, as well as above the bearing, to prevent material leakage or adhesion to the bearing.

[0021] The upper part of the vessel body 1 is provided with a viewing window and hand hole 13, and the upper part of the viewing window and hand hole 13 is covered with a glass viewing window, which can observe the reaction state, liquid level and fluidity of the material inside the vessel body 1.

[0022] In this embodiment, preheated polyphosphoric acid solvent is first added to the reactor body 1. Then, DAR hydrochloride, terephthalic acid, and phosphorus pentoxide powder are added in sequence and dispersed by stirring to ensure no powder accumulation on the surface. A vacuum is then evacuated from the reactor body 1 at the feeding port 2, and nitrogen is added to bring the pressure back to atmospheric pressure. This process is repeated three times to ensure the air inside the reactor body 1 is completely replaced. Next, the stirring motor 3 is started, with its rotation direction aligned with the spiral direction of the stirring belt 7, to stir the material. During stirring, the material is lifted along the inner wall of the reactor body 1 by the stirring belt 7. The wavy section of the stirring belt 7 causes the material flow path to undulate. Material flowing through the through-hole 8 generates micro-vortices at the outlet, breaking up gel clumps and P2O5 powder clumps attached to the surface of the stirring belt 7 or suspended in the liquid phase, preventing powder clump residue. After the reaction is complete, the stirring motor 3 is stopped, and the gear pump 12 is started for discharge.

Claims

1. A reactor for the preparation of PBO prepolymer, comprising a vessel body with a feeding port at the top and a discharge port at the bottom, and an anchor frame connected to a drive mechanism inside the vessel body, characterized in that: The lower part of the inner cavity of the vessel has a stirring belt that is at least partially inclined in the vertical direction and fixed to an anchor frame, and the stirring belt is provided with a set of through holes.

2. The reaction vessel for preparing PBO prepolymer according to claim 1, characterized in that: The stirring belt is at least one spiral belt wound around the anchor frame.

3. The reaction vessel for preparing PBO prepolymer according to claim 2, characterized in that: The stirring belt is wavy.

4. The reaction vessel for the preparation of PBO prepolymer according to claim 1, 2, or 3, characterized in that: The lower part of the mixing belt is connected to the lower part of the anchor frame via an inclined surface.

5. The reaction vessel for preparing PBO prepolymer according to claim 4, characterized in that: At least two mixing belts are wound around the anchor frame at intervals, and the lower part of each mixing belt is evenly or unevenly distributed along the circumference.

6. The reaction vessel for the preparation of PBO prepolymer according to claim 1, 2, or 3, characterized in that: A mounting plate with a through hole is provided at the discharge port at the lower end of the vessel body. A ring-shaped component with a bearing is installed inside the through hole. The ring-shaped component is fixedly connected to the mounting plate through the connecting part on its outer circumference. The lower end of the support rod, which is fixedly connected to the lower end of the anchor frame at its upper end, is connected to the bearing.

7. The reaction vessel for the preparation of PBO prepolymer according to claim 6, characterized in that: The support rod is inverted conical in shape.

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