A multilayer nested type centrifugal devolatilizer

Abstract

A multilayer nested type centrifugal devolatilizer, comprising a shell, a lower rotating disc and an upper rotating disc, the lower rotating disc is rotationally arranged in the shell, and the upper rotating disc is arranged in the shell and fixed to the lower rotating disc through a plurality of connecting pieces; a plurality of circular cone structures are coaxially nested on the lower rotating disc, and one of the circular cone structures is arranged at the middle part of the lower rotating disc; a plurality of inverted circular cone structures are coaxially nested on the upper rotating disc, and the inverted circular cone structures are respectively nested between two adjacent circular cone structures; a plurality of lower hole grooves are arranged on the bottom side of the circular cone structure; an upper hole groove is arranged on the bottom side of the inverted circular cone structure; an upper liquid inlet pipe is arranged in a rotating shaft and used for spraying liquid phase to the inner side wall of the innermost circular cone structure; the liquid phase flows from bottom to top and flows out through the upper hole groove; an air inlet is arranged at the bottom of the lower rotating disc, and an air outlet is arranged at the top of the upper rotating disc; the gas phase enters the outermost circular cone structure through the air inlet, forms countercurrent with the liquid phase and is discharged. The present application can ensure the renewal of the strengthened contact surface and improve the devolatilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of polymer devolatilization technology, specifically a multi-layer nested centrifugal devolatilizer. Background Technology

[0002] During polymer production and processing, some unreacted solvents and monomers, as well as other small-molecule volatile substances, inevitably remain in the polymer. These small molecules are not only harmful to health and the environment, but also reduce the performance of polymer products. Polymer devolatilization is a crucial step in improving product quality and reducing environmental and human hazards. Typically, polymer melts or solutions are viscous fluids with poor flowability, making it difficult for volatiles to diffuse. Furthermore, high viscosity results in thick liquid films and significant mass transfer resistance.

[0003] Due to the extremely limited diffusion of small molecules in high-viscosity systems, the fluid surface area and surface renewal rate become the main influencing factors in this process. Currently, various enhancement technologies have emerged for polymer devolatilization processes, such as falling film devolatilization and high-gravity rotating bed enhanced devolatilization. Chinese patent CN105944651B discloses a multi-layer falling film polycondensation reactor, which uses a conical section to induce a significant expansion and contraction of the liquid film and an inverted frustum structure to alter the gas-liquid contact surface, resulting in a good surface renewal effect. However, this device suffers from insufficient self-cleaning ability and susceptibility to clogging, making it difficult to handle systems prone to coking, and its liquid film renewal rate is significantly lower than that of dynamic devolatilization reactors. Chinese patent CN101372522A discloses a method and apparatus for removing polymer volatiles. This patent, in a high-gravity environment, forces the polymer fluid to flow along a path specified by a shaped packing material, thereby enhancing contact surface renewal and generating local disturbances. It has the advantages of short liquid holding time and good liquid phase fragmentation effect. However, due to the short liquid holding time, the diffusion time of small molecule volatiles is limited, resulting in problems such as weak devolatization ability and high energy consumption. Summary of the Invention

[0004] The present invention aims to provide a multi-layer nested centrifugal devolatilizer that ensures the renewal of the reinforced contact surface and improves the devolatilization effect.

[0005] To solve the above technical problems, the specific solution adopted by the present invention is a multi-layer nested centrifugal devolatilizer, including a shell, a lower turntable and an upper turntable. The lower turntable is rotatably disposed inside the shell by a rotating shaft passing through the bottom of the shell. The upper turntable is disposed inside the shell and located directly above the lower turntable. The upper turntable is fixed to the lower turntable by multiple connecting parts.

[0006] The lower turntable has multiple frustum structures nested around the same center, with one frustum structure located at the innermost center of the lower turntable; the upper turntable has multiple inverted frustum structures nested around the same center, with each inverted frustum structure embedded between two adjacent frustum structures; the frustum structures have multiple lower slots along their circumference on their bottom side near the lower turntable; the inverted frustum structures have multiple upper slots distributed along their circumference on their bottom side near the upper turntable.

[0007] A liquid inlet pipe is installed inside the rotating shaft. The upper end of the liquid inlet pipe is located in the innermost frustum structure in the middle of the lower turntable. The liquid inlet pipe is used to spray the liquid phase onto the inner wall of the innermost frustum structure and flow from top to bottom through the lower slot into the adjacent inverted frustum structure. The liquid phase flows from bottom to top and flows out through the upper slot.

[0008] The bottom of the lower turntable has multiple air inlets distributed circumferentially within the outermost frustum structure, while the top of the upper turntable has multiple exhaust ports around its center within the innermost frustum structure. The gas phase enters the outermost frustum structure through the air inlets and flows from bottom to top through the upper slots on the adjacent inverted frustum structure, forming a countercurrent flow with the liquid phase before being discharged through the exhaust ports.

[0009] As another optimized solution for the aforementioned multi-layer nested centrifugal devolatilizer: the number of frustum structures is three, and the number of inverted frustum structures is two. The nesting structure of the frustum structures and inverted frustum structures, from the inside out, is frustum structure-inverted frustum structure-frustum structure-inverted frustum structure-frustum structure.

[0010] As another optimized solution for the aforementioned multi-layer nested centrifugal devourer: the taper of the inverted frustum in the inverted frustum structure is 1:8, and the taper of the frustum in the frustum structure is 10:1.

[0011] As another optimization of the aforementioned multi-layer nested centrifugal devolatilizer, a liquid inlet pipe is provided with a liquid phase nozzle near the top outer periphery of the upper turntable for spraying the liquid phase onto the inner wall of the innermost frustum structure.

[0012] As another optimized solution for the aforementioned multi-layer nested centrifugal devolatilizer: a sealing ring is provided between the bottom of the outer shell and the bottom surface of the lower turntable, and a sealing ring is installed between the top of the outer shell and the upper side of the corresponding upper turntable.

[0013] As another optimized solution for the aforementioned multi-layer nested centrifugal devolatilizer, a liquid storage groove for temporarily storing liquid is provided at the bottom of the outer shell, outside the lower turntable.

[0014] As another optimization of the above-mentioned multi-layer nested centrifugal devolatilizer, a drain pipe is provided in the liquid storage groove for the liquid in the storage groove to flow out.

[0015] As another optimized solution for the aforementioned multi-layer nested centrifugal devourer: an air inlet pipe is provided at the bottom of the outer casing, through which the gas supply phase enters the outermost frustum structure, and an exhaust pipe is provided at the top of the outer casing, directly above the exhaust port, through which the gas supply phase exits from the outer casing.

[0016] As another optimized solution for the aforementioned multi-layer nested centrifugal devolatilizer: the connecting component is a fixed support connecting rod, with the lower end of the fixed support connecting rod fixed to the lower turntable and the upper end of the fixed support connecting rod fixed to the upper turntable.

[0017] As another optimized solution for the aforementioned multi-layer nested centrifugal devolatilizer: the bottom of the outer casing is provided with a mounting hole for mounting a rotating shaft, and a bearing for rotating the rotating shaft is installed in the mounting hole, with the rotating shaft installed inside the bearing.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. In this invention, the lower turntable and the upper turntable are connected by a fixed support connecting rod and are nested with a frustum structure and an inverted frustum structure at intervals. The liquid inlet pipe is inserted into the rotating shaft fixed at the bottom of the lower turntable. The liquid inlet pipe can rotate with the rotating shaft. Under centrifugal force, the liquid phase in the liquid inlet pipe can be evenly sprayed onto the inner wall of the frustum structure set in the middle of the lower turntable. The liquid phase film on the inner wall of the frustum structure is thin, uniform and stable. Furthermore, the liquid phase sprayed onto the innermost frustum structure's inner wall flows downwards and through the lower slot on the bottom side where the frustum structure contacts the lower rotating disk, flowing into the gap between the innermost frustum structure and an adjacent inverted frustum structure. Under centrifugal force, it flows upwards along the inner wall of the inverted frustum structure. The liquid phase can also flow out through the upper slot on the top side where the inverted frustum structure contacts the upper rotating disk. Thus, after passing through multiple frustum and inverted frustum structures, the liquid phase finally flows out through the slot structure between the frustum structure and the lower rotating disk, merging into the groove at the bottom of the outer shell and being discharged through the drain pipe. The liquid phase flows outwards in a zigzag pattern from the innermost side, while the gas phase enters from the outermost air inlet pipe and begins to flow inwards before being discharged through the exhaust port. The gas and liquid phases are in countercurrent contact, allowing for the entrainment of each other. In this invention, the liquid phase continuously renews the gas-liquid contact area as it flows along the inner walls of the frustum and inverted frustum structures. Small molecule volatiles continuously diffuse from the liquid phase to the gas phase under the driving force of the equilibrium concentration difference. Compared with existing technologies, this invention has stronger self-cleaning ability and is less prone to clogging. Moreover, while ensuring enhanced contact surface renewal, this invention also features a long liquid holding time, a long gas phase flow, and a long gas-liquid contact time, resulting in good volatilization removal efficiency. Compared with existing high-gravity rotating beds, this invention improves the volatile matter removal efficiency by 20-40%.

[0020] 2. In this invention, a sealing ring is provided between the upper turntable and the upper side of the outer shell to prevent gas short circuit. Attached Figure Description

[0021] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0022] Figure 2 This is a schematic diagram of the upper slot on the frustum structure and the lower slot on the inverted frustum structure in this invention.

[0023] Figure 3 This is a schematic diagram of the structure of the present invention, in which an exhaust port is provided on the upper turntable and an air inlet is provided on the lower turntable.

[0024] Figure 4 This is a schematic diagram showing the flow direction of the liquid phase and the gas phase in this invention;

[0025] Figure 5 This is a schematic diagram of the force analysis of liquid phase film formation.

[0026] Reference numerals: 1. Outer shell; 101. Exhaust pipe; 102. Liquid storage groove; 103. Drain pipe; 104. Air inlet pipe; 2. Upper turntable; 201. Exhaust port; 3. Frustum structure; 301. Lower slot; 302. First frustum structure; 303. Second frustum structure; 304. Third frustum structure; 4. Inverted frustum structure; 401. Upper slot; 402. Second inverted frustum structure; 403. First inverted frustum structure; 5. Sealing ring; 6. Fixed support connecting rod; 7. Lower turntable; 701. Air inlet; 8. Rotating shaft; 9. Liquid inlet pipe; 901. Liquid phase nozzle. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Parts not described in detail in the following embodiments of the present invention, such as components that drive the rotating shaft to rotate, should be understood as prior art known or should be known by those skilled in the art.

[0028] A multi-layer nested centrifugal devolatilizer, such as Figure 1-5 As shown, the centrifugal devolatilizer includes a housing 1, inside which are an upper rotating disk 2 and a lower rotating disk 7, which are parallel to each other. The upper rotating disk 2 is located inside the housing 1 and directly above the lower rotating disk 7, with a distance of 300mm between them. The upper rotating disk 2 and the lower rotating disk 7 are connected by multiple fixed support connecting rods 6 arranged circumferentially along the two rotating disks. The upper end of the fixed support connecting rod 6 is fixed to the bottom surface of the upper rotating disk 2 near its outer side, and the lower end of the fixed support connecting rod 6 is fixed to the upper side surface of the lower rotating disk 7 near its outer side.

[0029] Three frustum structures 3 are nested between the lower turntable 7 and the upper turntable 2, arranged from the inside out. The frustum structures 3 are made of metal or ceramic. The taper of the frustum structure 3 is 10:1. The centers of the three frustum structures 3 coincide with the center of the lower turntable 7. The diameters of the three frustum structures 3 increase proportionally from the inside out, and the spacing between the three frustum structures 3 is equal. The innermost frustum structure 3 closest to the center of the lower turntable 7 is the first frustum structure 302, and the others are called the second frustum structure 303 and the third frustum structure 304 from the inside out. Multiple rectangular lower slots 301 are provided on the lower side of the bottom where the three frustum structures 3 contact the lower turntable 7. The multiple lower slots 301 are evenly spaced along the bottom circumference of the corresponding frustum structures 3.

[0030] Two inverted frustum structures 4 are arranged between the lower turntable 7 and the upper turntable 2. The inverted frustum structures 4 are made of metal or ceramic, and the taper of the inverted frustum in the inverted frustum structure 4 is 1:8. The center of the two inverted frustum structures 4 coincides with the center of the middle of the upper turntable 2. The two inverted frustum structures 4 are nested between the first frustum structure 302 and the second frustum structure 303, and between the second frustum structure 303 and the third frustum structure 304, respectively. The two inverted frustum structures 4 are referred to as the first inverted frustum structure 403 and the second inverted frustum structure 402 from the inside to the outside.

[0031] Therefore, the three frustum structures 3 and the two inverted frustum structures 4 form a nested structure from the inside out: first frustum structure 302 - first inverted frustum structure 403 - second frustum structure 303 - second inverted frustum structure 402 - third frustum structure 304. Furthermore, multiple upper slots 401 are provided on the top sides of the two inverted frustum structures 4 that contact the upper turntable 2. These upper slots 401 are evenly spaced along the circumference of the corresponding upper sides of the inverted frustum structures 4, and the width and height of each upper slot 401 are 20 x 30 mm.

[0032] A rotating shaft 8 is fixed in the middle of the bottom surface of the lower turntable 7. The lower turntable 7 is suspended in the housing 1 and can rotate with the rotating shaft 8 as the center of rotation. A mounting hole is provided on the bottom surface of the housing 1. A bearing for the rotating shaft 8 to pass through and rotate is installed in the mounting hole. The upper end of the rotating shaft 8 passes through the bearing and is fixed to the bottom surface of the lower turntable 7. A liquid inlet pipe 9 is installed in the rotating shaft 8. The upper end of the liquid inlet pipe 9 passes through the rotating shaft 8 and is installed in the innermost frustum structure 3 in the middle of the lower turntable 7. The upper end of the liquid inlet pipe 9 is located near the upper turntable 2, and the lower end of the liquid inlet pipe 9 is inside the rotating shaft 8.

[0033] The bottom of the inlet pipe 9 can be connected to a conveying pipe for conveying liquid phase, so that the liquid phase can be conveyed to the inlet pipe 9 through the conveying pipe. Two liquid phase nozzles 901 are arranged around the upper outer periphery of the inlet pipe 9. The liquid phase in the inlet pipe 9 can be sprayed from the nozzles onto the inner wall of the upper part of the first frustum structure 302 located on its outer periphery under the action of centrifugal force generated during the rotation of the inlet pipe 9.

[0034] like Figure 4 As shown, the liquid phase sprayed onto the upper inner wall of the innermost first frustum structure 302 can flow down its inner wall under the centrifugal force generated by the rotation of the lower turntable 7, and then through the lower groove 301 on the lower side of the innermost first frustum structure 302 to the lower inner wall of the adjacent first inverted frustum structure 403, as shown. Figure 5 As shown, the liquid phase on the inner wall of the inverted frustum is subjected to centrifugal force F, the supporting force f of the inverted frustum, and gravity g. When F is at its maximum, the resultant force F' of F and f will be much greater than g, thus giving the liquid phase a resultant force much greater than g. Therefore, under the action of centrifugal force, the liquid phase can achieve a film formation rate and efficiency on the inner surface of the inverted frustum that is much greater than that under gravity, thereby improving the liquid film renewal rate, enhancing gas-liquid contact, and improving devolatilization efficiency. When the liquid phase is on the inner wall of the frustum, F' will be much greater than g, and the two forces mutually promote the effect of liquid phase film formation, resulting in a better liquid phase film formation effect.

[0035] As the lower rotating disk 7 continues to rotate, the liquid phase moves along the lower part of the inner wall of the first inverted frustum structure 403 to its upper part under the centrifugal force, and then moves through the upper hole groove 401 on the upper side of the first inverted frustum structure 403 to the inner wall of the upper part of the adjacent second frustum structure 303. As the lower turntable 7 continues to rotate, the liquid phase flows from the upper part to the lower part along the inner wall of the upper part of the second frustum structure 303, and moves to the lower inner wall of the adjacent second inverted frustum structure 402 through the lower hole groove 301 on the lower side of the second frustum structure 303. Under the centrifugal force generated by the rotation of the lower turntable 7, the liquid phase continues to flow to the upper part of the lower inner wall of the second inverted frustum structure 402, and moves to the upper inner wall of the adjacent third frustum structure 304 through the upper hole groove 401 on the upper side of the second inverted frustum structure 402. The liquid phase flows to the lower part of the third frustum structure 304 through the inner wall of the third frustum structure 304, and flows into the outer shell 1 through the lower hole groove 301 provided on the lower side of the third frustum structure 304.

[0036] Furthermore, a liquid storage groove 102 is provided at the bottom of the outer casing 1 on the outer periphery of the lower turntable 7. A drain pipe 103 is provided in the liquid storage groove 102, and the drain pipe 103 is connected to a drain pipe for liquid phase discharge. The liquid phase flows from the lower hole groove 301 on the third frustum structure 304 to the liquid storage groove 102 and converges. The converged liquid phase can be discharged from the outer casing 1 through the drain pipe 103.

[0037] Furthermore, such as Figure 1 , Figure 3 and Figure 4 As shown, an air inlet pipe 104 for gas phase to enter the housing 1 is provided on the bottom surface of the housing 1 on the left side of the rotating shaft 8. Six air inlets 701 are provided on the lower turntable 7 between the outermost third frustum structure 304 and the second inverted frustum structure 402. The six air inlets 701 are evenly spaced around the liquid inlet pipe 9. The gas phase enters the outermost third frustum structure 304 through the air inlets 701 and rises.

[0038] The gas phase rises and, under the action of pressure difference, descends through the upper slot 401 on the upper side of the adjacent second inverted frustum structure 402. The descending gas phase rises through the lower slot 301 on the lower side of the second frustum structure 303. The rising gas phase descends through the upper slot 401 on the upper side of the adjacent first inverted frustum structure 403. The descending gas phase rises again through the lower slot 301 on the lower side of the adjacent first frustum structure 302.

[0039] Four exhaust ports 201 are arranged around the center of the upper turntable 2. The four exhaust ports 201 are evenly spaced and communicate with the inner cavity of the first frustum structure 302. An exhaust pipe 101 is arranged on the top of the outer shell 1 directly above the four exhaust ports 201. The rising gas phase inside the first frustum structure 302 can be discharged through the exhaust ports 201 and the exhaust pipe 101.

[0040] The gas phase enters from the outermost inlet pipe 104 and begins to flow in a tortuous manner towards the inside, carrying away the small molecules that have been volatilized, and is then discharged through the exhaust pipe 101. The gas phase has a long flow path. Meanwhile, the liquid phase begins to flow in a tortuous manner from the innermost side towards the outside. The gas and liquid phases are in countercurrent contact as a whole, resulting in a longer gas-liquid contact time and improved volatilization efficiency.

[0041] Furthermore, a sealing ring 5 is provided between the bottom of the outer casing 1 and the bottom surface of the lower turntable 7, and a sealing ring 5 is installed between the top of the outer casing 1 and the upper side surface of the corresponding upper turntable 2. The sealing ring 5 can prevent gas short circuit.

Claims

1. A multi-layer nested centrifugal devolatilizer, characterized in that: It includes a housing (1), a lower turntable (7) and an upper turntable (2). The lower turntable (7) is rotatably disposed inside the housing (1) by means of a rotating shaft (8) passing through the bottom of the housing (1). The upper turntable (2) is disposed inside the housing (1) and located directly above the lower turntable (7). The upper turntable (2) is fixed to the lower turntable (7) by means of multiple connecting parts. Multiple frustum structures (3) are nested in the same center on the lower turntable (7), one of which is located at the innermost part of the middle of the lower turntable (7); multiple inverted frustum structures (4) are nested in the same center on the upper turntable (2), and the inverted frustum structures (4) are respectively embedded between two adjacent frustum structures (3); multiple lower holes (301) are opened along the circumference on the bottom side of the frustum structure (3) near the lower turntable (7); multiple upper holes (401) are provided along the circumference on the bottom side of the inverted frustum structure (4) near the upper turntable (2); A liquid inlet pipe (9) is installed inside the rotating shaft (8). The upper end of the liquid inlet pipe (9) is located in the innermost frustum structure (3) in the middle of the lower turntable (7). The liquid inlet pipe (9) is used to spray the liquid phase onto the inner wall of the innermost frustum structure (3) and flow from top to bottom through the lower hole groove (301) into the adjacent inverted frustum structure (4). The liquid phase flows from bottom to top and flows out through the upper hole groove (401). The bottom of the lower turntable (7) is located in the outermost frustum structure (3) and has multiple air inlets (701) distributed along its circumference. The top of the upper turntable (2) is located in the innermost frustum structure (3) and has multiple exhaust ports (201) around its center. The gas phase enters the outermost frustum structure (3) through the air inlet (701) and flows from bottom to top through the upper hole groove (401) on the adjacent inverted frustum structure (4) to form a countercurrent with the liquid phase and is discharged through the exhaust port (201).

2. The multi-layer nested centrifugal devolatilizer according to claim 1, characterized in that: There are three frustum structures (3) and two inverted frustum structures (4). The nested structure of frustum structures (3) and inverted frustum structures (4) from the inside out is frustum structure (3) - inverted frustum structure (4) - frustum structure (3) - inverted frustum structure (4) - frustum structure (3).

3. A multi-layer nested centrifugal devolatilizer according to claim 2, characterized in that: The taper of the inverted frustum in the inverted frustum structure (4) is 1:8, and the taper of the frustum in the frustum structure (3) is 10:

1.

4. A multi-layer nested centrifugal devolatilizer according to claim 1, characterized in that: The liquid inlet pipe (9) is provided with a liquid phase nozzle (901) on the outer periphery of the top end of the upper turntable (2) for spraying the liquid phase onto the inner wall of the innermost frustum structure (3).

5. A multi-layer nested centrifugal devolatilizer according to claim 1, characterized in that: A sealing ring (5) is provided between the bottom of the outer shell (1) and the bottom surface of the lower turntable (7), and a sealing ring (5) is installed between the top of the outer shell (1) and the upper side of the corresponding upper turntable (2).

6. A multi-layer nested centrifugal devolatilizer according to claim 1, characterized in that: The bottom of the outer casing (1) is provided with a liquid storage groove (102) for temporarily storing liquid on the outside of the lower turntable (7).

7. A multi-layer nested centrifugal devolatilizer according to claim 6, characterized in that: The liquid storage groove (102) is provided with a drain pipe (103) for the liquid in the liquid storage groove (102) to flow out.

8. A multi-layer nested centrifugal devolatilizer according to claim 6, characterized in that: The bottom of the outer casing (1) is provided with an air inlet pipe (104) through which the air supply phase enters the outermost frustum structure (3) from the air inlet (701), and the top of the outer casing (1) is provided with an exhaust pipe (101) directly above the exhaust port (201) through which the air supply phase exits from the outer casing (1).

9. A multi-layer nested centrifugal devolatilizer according to claim 1, characterized in that: The connector is a fixed support connecting rod (6), the lower end of which is fixed to the lower turntable (7), and the upper end of which is fixed to the upper turntable (2).

10. A multi-layer nested centrifugal devolatilizer according to claim 1, characterized in that: The bottom of the outer casing (1) is provided with a mounting hole for mounting the rotating shaft (8), and a bearing for the rotating shaft (8) to rotate is installed in the mounting hole. The rotating shaft (8) is installed in the bearing.

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