Polypropylene fluidized bed dryer

Abstract

The utility model relates to the technical field of polypropylene production, in particular to a polypropylene fluidized bed dryer. Comprising an upper sealing head, a cone transition section, a middle barrel and a lower sealing head which are sequentially connected from top to bottom, a discharging channel is further formed in the middle barrel, a first drying medium inlet is formed in one side of the middle barrel, and an annular first fluidization distribution plate is horizontally arranged above the position, corresponding to the first drying medium inlet, in the middle barrel; a baffle is arranged perpendicular to the first fluidization distribution plate and arranged in the radial direction of the annular first fluidization distribution plate, discharging holes are formed in the positions, close to the baffle and the first fluidization distribution plate, of the wall of the discharging channel, and spoilers are arranged on the inner wall, close to one side of the baffle, of the middle cylinder and the outer wall of the discharging channel. Through the spoiler, the contact time of the polypropylene powder and the hot nitrogen can be prolonged and the drying effect can be improved by continuously changing the moving direction of the hot nitrogen and turning back and forth before the polypropylene powder falls into the discharging channel from the discharging hole.

Description

Technical Field

[0001] The utility model relates to the technical field of polypropylene production, in particular to a polypropylene fluidized bed dryer. Background Art

[0002] The fluidized bed dryer is a key unit in a polypropylene plant. Its hallmarks include rapid heat and moisture transfer between the polypropylene powder and the heated nitrogen, resulting in high drying speeds, high processing capacity, and stable operation. The fluidized bed dryer is a vertical cylindrical dryer. Its most significant feature is the cylindrical internal component, which provides directional movement of the polypropylene powder within the fluidized bed, increasing the material's residence time within the bed and ensuring drying quality.

[0003] The polypropylene plant's dryer utilizes a double-layer vertical fluidized bed. When the polypropylene plant is operating at full capacity, the fluidized bed dryer performs poorly on the polypropylene powder. The moisture carried by the polypropylene powder after steaming in the steamer cannot be fully dried, resulting in significant water contamination in the nitrogen delivered by the pneumatic conveying system. Regular drainage from the pneumatic conveying blower outlet cooler is required to maintain normal production. During this period, efforts to reduce the moisture content of the polypropylene powder, including adjusting the steam flow rate in the steamer and lowering the drying nitrogen temperature, were ineffective. The underlying cause is that when the polypropylene plant is operating at full capacity, the polypropylene powder's residence time in the fluidized bed dryer is short, resulting in limited contact time between the powder and the drying nitrogen. This results in poor drying performance and excessive moisture content. Improving the residence time of the polypropylene powder in the fluidized bed dryer and improving drying efficiency are pressing challenges. Utility Model Content

[0004] The utility model provides a polypropylene fluidized bed dryer to solve the problem that the residence time of polypropylene powder in the fluidized bed dryer is short and the contact time between the polypropylene powder and hot nitrogen is short, resulting in poor drying effect.

[0005] In order to solve the above problems, the technical solution of the present utility model is:

[0006] The polypropylene fluidized bed dryer described in the utility model comprises an upper head, a conical transition section, a middle cylinder and a lower head connected in sequence from top to bottom. A discharge channel is further provided inside the middle cylinder, and the discharge channel passes through the lower head. A drying medium outlet is provided on the top of the upper head, and a polypropylene discharge port is provided at the bottom of the discharge channel. A second drying medium inlet is provided on one side close to the bottom of the discharge channel. A second fluidized distribution plate is provided in the discharge channel at an inclined position corresponding to the second drying medium inlet and close to the inner wall of the discharge channel. A first drying medium inlet is provided on one side of the middle cylinder. The middle cylinder has an annular first fluidizing distribution plate horizontally arranged above the first drying medium inlet position, and a baffle is arranged perpendicular to the first fluidizing distribution plate. The baffle is arranged along the radial direction of the annular first fluidizing distribution plate, and its two ends are respectively connected to the inner wall of the middle cylinder and the outer wall of the discharge channel. A discharge hole is provided on the wall of the discharge channel near the baffle and the first fluidizing distribution plate. The upper end of the polypropylene feed pipe is provided in the upper head, and the lower end is deep into the middle cylinder and is located above the first fluidizing distribution plate. A spoiler is provided on the inner wall of the middle cylinder and the outer wall of the discharge channel near the baffle side.

[0007] The spoiler can be set before the polypropylene powder falls into the feeding channel from the discharge hole, by continuously changing the movement direction of the hot nitrogen and turning back and forth, thereby prolonging the contact time between the polypropylene powder and the hot nitrogen and improving the drying effect.

[0008] Furthermore, the annular first fluidization distribution plate is composed of a plurality of sector-shaped grid plates, and tongue-shaped holes are provided on the sector-shaped grid plates.

[0009] Furthermore, the tongue-shaped holes are arranged in multiple rows along the radial direction of the sector-shaped grille plate.

[0010] Furthermore, every three rows of tongue-shaped holes on the sector grille plate form a group, and the opening directions of the tongue-shaped holes are respectively along the tangent direction of the sector grille plate, inclined toward the outer diameter along the tangent direction of the sector grille plate, and inclined toward the inner diameter along the tangent direction of the sector grille plate.

[0011] Furthermore, the tongue-shaped hole is opened in an upward and downward inclination angle of ≤30° along the tangent direction of the sector-shaped grille plate.

[0012] By designing the arrangement direction and inclination angle of the tongue-shaped holes, they are not completely along the tangential direction. Therefore, when the hot nitrogen moves in a circular motion, the trajectory is longer, thereby extending the contact time between the polypropylene powder and the hot nitrogen and improving the drying effect.

[0013] The tongue-shaped holes of the second fluidized distribution plate are all opened along the tangential direction.

[0014] Furthermore, the surface of the spoiler is a plurality of vertically arranged triangular prisms.

[0015] Working principle:

[0016] In the polypropylene fluidized bed dryer, the interior of the cone transition section is a dilute phase zone, the interior of the middle cylinder is a dense phase zone, and the discharge channel near the polypropylene discharge port is a filling zone.

[0017] Polypropylene powder enters from the polypropylene feed pipe, falls into the dense phase area, and falls onto the first fluidized distribution plate. Hot nitrogen enters from the first drying medium inlet tangent to the middle cylinder, and makes circular motion along the tangent direction through the tongue-shaped holes on the first fluidized distribution plate. Because the tongue-shaped holes are opened in groups of three, each with an inclination angle, and not completely along the tangent direction, the hot nitrogen has a longer trajectory when making circular motion, thereby extending the contact time between the polypropylene powder and the hot nitrogen. Under the spray of hot nitrogen, the polypropylene powder is After being fluidized and dried on the fluidized distribution plate, the hot nitrogen gas will bypass the baffle for a week and change its direction of movement. This further prolongs the contact time between the polypropylene powder and the hot nitrogen. Finally, the polypropylene powder enters the discharge channel from the discharge hole and falls to the filling area. The hot nitrogen gas enters from the second drying medium inlet and is distributed by the second fluidized distribution plate, loosening the material and carrying moisture upward. The polypropylene powder that has undergone secondary drying is discharged from the polypropylene discharge port. The hot nitrogen gas moves upward and is discharged from the drying medium outlet at the top through the dilute phase area.

[0018] The beneficial effects of the utility model are as follows:

[0019] (1) The utility model is designed with a spoiler that can continuously change the direction of movement of hot nitrogen before the polypropylene powder falls into the discharge channel from the discharge hole, thereby extending the contact time between the polypropylene powder and the hot nitrogen and improving the drying effect.

[0020] (2) The arrangement direction and tilt angle of the tongue-shaped holes are designed in the present invention so that they are not completely along the tangential direction. Therefore, when the hot nitrogen moves in a circular motion, the trajectory is longer, thereby extending the contact time between the polypropylene powder and the hot nitrogen and improving the drying effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. In the accompanying drawings:

[0022] Figure 1 This is a schematic structural diagram of the polypropylene fluidized bed dryer described in the present utility model;

[0023] Figure 2 A top view of the first fluidizing distribution plate of the present invention;

[0024] Figure 3 for Figure 2 A magnified stereogram of center A;

[0025] Figure 4 This is a top view of the fan-shaped grille plate described in the present utility model;

[0026] Figure 5 It is a side view of the tongue-shaped hole described in the utility model;

[0027] In the figure: 1. Polypropylene feed pipe; 2. Upper head; 3. Lower head; 4. Conical transition section; 5. Discharge channel; 6. Middle cylinder; 7. Filling area; 8. Dense phase area; 9. Dilute phase area; 10. Drying medium outlet; 11. Polypropylene discharge port; 12. First drying medium inlet; 13. First fluidization distribution plate; 1301. Discharge hole; 1302. Fan-shaped grid plate; 1303. Tongue-shaped hole; 14. Second drying medium inlet; 15. Second fluidization distribution plate; 16. Baffle; 17. Spoiler. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below in conjunction with the embodiments.

[0029] Example 1

[0030] like Figure 1-5 As shown, the polypropylene fluidized bed dryer comprises an upper head 2, a conical transition section 4, a middle cylinder 6, and a lower head 3 connected in sequence from top to bottom. A discharge channel 5 is further provided inside the middle cylinder 6. The discharge channel 5 passes through the lower head 3. A polypropylene discharge port 11 is provided at the bottom of the discharge channel 5. A second drying medium inlet 14 is provided on one side near the bottom of the discharge channel 5. A second fluidized distribution plate 15 is provided in the discharge channel 5 at an inclined position corresponding to the second drying medium inlet 14 and close to the inner wall of the discharge channel 5. A first drying medium inlet 12 is provided on one side of the middle cylinder 6. The inside of the middle cylinder 6 corresponds to the first drying medium inlet 14. An annular first fluidizing distribution plate 13 is horizontally provided above the drying medium inlet 12, and a baffle 16 is provided perpendicular to the first fluidizing distribution plate 13. The baffle 16 is arranged along the radial direction of the annular first fluidizing distribution plate 13, and its two ends are respectively connected to the inner wall of the middle cylinder 6 and the outer wall of the discharge channel 5. A discharge hole 1301 is provided on the wall of the discharge channel 5 near the baffle 16 and the first fluidizing distribution plate 13. The upper end of the polypropylene feed pipe 1 is provided in the upper head 2, and the lower end penetrates into the middle cylinder 6 and is located above the first fluidizing distribution plate 13. A spoiler 17 is provided on the inner wall of the middle cylinder 6 and the outer wall of the discharge channel 5 near the side of the baffle 16.

[0031] The spoiler 17 can be set to continuously change the movement direction of the hot nitrogen before the polypropylene powder falls into the discharge channel 5 from the discharge hole 1301, thereby prolonging the contact time between the polypropylene powder and the hot nitrogen and improving the drying effect.

[0032] It can be understood that the annular first fluidization distribution plate 13 is composed of a plurality of sector-shaped grid plates 1302 , and tongue-shaped holes 1303 are opened on the sector-shaped grid plates 1302 .

[0033] It can be understood that the tongue-shaped holes 1303 are arranged in multiple rows along the radial direction of the sector-shaped grille plate 1302.

[0034] It can be understood that every three rows of tongue-shaped holes 1303 on the fan-shaped grille plate 1302 form a group, and the opening directions of the tongue-shaped holes 1303 are respectively along the tangent direction of the fan-shaped grille plate 1302, inclined toward the outer diameter along the tangent direction of the fan-shaped grille plate 1302, and inclined toward the inner diameter along the tangent direction of the fan-shaped grille plate 1302.

[0035] It can be understood that the tongue-shaped hole 1303 is opened at an angle of 30° along the tangent direction of the sector-shaped grid plate 1302 .

[0036] By designing the arrangement direction and tilt angle of the tongue-shaped holes 1303 so as not to be completely along the tangential direction, the hot nitrogen has a longer trajectory when performing circular motion, thereby extending the contact time between the polypropylene powder and the hot nitrogen and improving the drying effect.

[0037] The tongue-shaped holes 1303 of the second fluidization distribution plate 15 are all opened along the tangential direction.

[0038] It can be understood that the surface of the spoiler 17 is a plurality of vertically arranged triangular prisms.

[0039] Working principle:

[0040] In the polypropylene fluidized bed dryer, the interior of the conical transition section 4 is a dilute phase zone 9 , the interior of the middle cylinder 6 is a dense phase zone 8 , and the discharge channel 5 near the polypropylene discharge port 11 is a filling zone 7 .

[0041] The polypropylene powder enters from the polypropylene feed pipe 1, falls to the dense phase area 8, and falls on the first fluidized distribution plate 13. The hot nitrogen enters from the first drying medium inlet 12 tangent to the middle cylinder 6, and makes a circular motion along the tangent direction through the tongue-shaped holes 1303 on the first fluidized distribution plate 13. Because the tongue-shaped holes 1303 are opened in a group of three rows, each with an inclination angle, and not completely along the tangent direction, the hot nitrogen has a longer trajectory when making a circular motion, thereby extending the contact time between the polypropylene powder and the hot nitrogen. Under the spray of hot nitrogen, the polypropylene powder is After being fluidized and dried on the distribution plate 13, the hot nitrogen gas, after passing through one circle, is redirected by the spoilers 17 on both sides of the baffle 16, further extending the contact time between the polypropylene powder and the hot nitrogen. Finally, the polypropylene powder enters the discharge channel 5 from the discharge hole 1301 and falls to the filling area 7. The hot nitrogen gas enters from the second drying medium inlet 14 and is distributed by the second fluidized distribution plate 15, loosening the material and carrying moisture upward. The polypropylene powder that has undergone secondary drying is discharged from the polypropylene discharge port 11. The hot nitrogen gas moves upward, passes through the dilute phase zone 9, and is discharged from the drying medium outlet 10 at the top.

[0042] The above description is merely an embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of the claims of the present invention.

Claims

1. A polypropylene fluidized bed dryer, characterized in that: The invention comprises an upper head (2), a cone transition section (4), a middle cylinder (6), and a lower head (3) connected in sequence from top to bottom. A material discharge channel (5) is further provided inside the middle cylinder (6). The material discharge channel (5) passes through the lower head (3). A drying medium outlet (10) is provided at the top of the upper head (2). A polypropylene discharge port (11) is provided at the bottom of the material discharge channel (5). A second drying medium inlet (14) is provided on one side close to the bottom of the material discharge channel (5). A second fluidized distribution plate (15) is provided in the material discharge channel (5) at an inclined position corresponding to the second drying medium inlet (14) and close to the inner wall of the material discharge channel (5). A first drying medium inlet (12) is provided on one side of the middle cylinder (6). The inside of the middle cylinder (6) corresponds to the first drying medium inlet (12). An annular first fluidizing distribution plate (13) is horizontally provided above a drying medium inlet (12), and a baffle (16) is provided perpendicular to the first fluidizing distribution plate (13). The baffle (16) is arranged along the radial direction of the annular first fluidizing distribution plate (13), and its two ends are respectively connected to the inner wall of the middle cylinder (6) and the outer wall of the discharge channel (5). A discharge hole (1301) is provided on the wall of the discharge channel (5) near the baffle (16) and the first fluidizing distribution plate (13). The upper end of the polypropylene feed pipe (1) is provided on the upper head (2), and the lower end is extended into the middle cylinder (6) and is located above the first fluidizing distribution plate (13). A spoiler (17) is provided on the inner wall of the middle cylinder (6) and the outer wall of the discharge channel (5) near the baffle (16).

2. The polypropylene fluidized bed dryer according to claim 1, characterized in that The annular first fluidization distribution plate (13) is composed of a plurality of fan-shaped grid plates (1302), and tongue-shaped holes (1303) are provided on the fan-shaped grid plates (1302).

3. The polypropylene fluidized bed dryer according to claim 2, characterized in that The tongue-shaped holes (1303) are arranged in multiple rows along the radial direction of the sector-shaped grid plate (1302).

4. The polypropylene fluidized bed dryer according to claim 3, characterized in that Each three rows of tongue-shaped holes (1303) on the fan-shaped grille plate (1302) form a group, and the opening directions of the tongue-shaped holes (1303) are respectively along the tangent direction of the fan-shaped grille plate (1302), inclined toward the outer diameter along the tangent direction of the fan-shaped grille plate (1302), and inclined toward the inner diameter along the tangent direction of the fan-shaped grille plate (1302).

5. The polypropylene fluidized bed dryer according to claim 4, characterized in that: The tongue-shaped hole (1303) is opened in an upward and downward inclination angle of ≤30° along the tangent direction of the fan-shaped grid plate (1302).

6. The polypropylene fluidized bed dryer according to claim 1, characterized in that The surface of the spoiler (17) is a plurality of vertically arranged triangular prisms.

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