A wall-adhering falling film devolatilizer

Abstract

The application discloses a wall-attached falling film devolatilizer, which comprises a devolatilization kettle, a vacuum system and internal components in the devolatilization kettle, a melt pool is arranged between the devolatilization kettle and the internal components, the internal components comprise a flash chamber and a sleeve connected in sequence from top to bottom, the sleeve comprises a polymer tube and an oil tube sleeved outside the polymer tube, polymer solution enters the flash chamber through the sleeve from bottom to top, and then falls to the inner wall of the devolatilization kettle to flow into the melt pool in the form of falling film. The falling film devolatilizer is compact in overall structure, small in volume and capable of saving the arrangement space of the equipment by arranging the sleeve and making the falling film on the inner wall of the devolatilization kettle. The polymer fluid is flashed in the flash chamber, the gas content in the fluid is reduced, the falling strips formed from the distributor are not easy to break, and the residence time of the falling film is longer and more controllable.

Description

Technical Field

[0001] This invention relates to the field of devolatilization devices, specifically to a wall-mounted falling film devolatilizer. Background Technology

[0002] In existing technologies, devolatilization is a crucial step in chemical production, its task being to transfer volatile substances from the liquid phase to the gas phase for removal from the fluid. The effectiveness of devolatilization directly impacts product quality and application areas, second only in importance to the polymerization reaction process and process formulation.

[0003] Currently, various devolatilization equipment is used in industrial fields. Dynamic rotary devolatilization equipment, represented by screw extruders and disc ring polycondensation reactors, while achieving advantages such as enhanced surface renewal and uniform material mixing through rotating stirring elements, suffers from overly complex structures and high manufacturing and operating costs. A distributor is a liquid distribution device installed at the top of a packed tower; its function is to uniformly distribute the liquid across the tower's cross-section, ensuring high-efficiency operation. Existing devolatilizers have a large overall volume. High-viscosity fluids enter the distributor and flow directly out from the distribution holes, failing to separate the gas and liquid phases. Furthermore, unstable or even intermittent fluid flow rates are prone to occur. When fluid passing through this distributor undergoes free film falling outside the tubes or inside a smooth, straight-plate devolatilization tower under the influence of gravity and inertia, the high viscosity of the solution makes it easy for polymers to adhere to the distributor surface. The falling film time is also long, resulting in some fluid not being devolatilized or exhibiting poor devolatilization effects. The falling film time is uncontrollable, leading to low devolatilization efficiency and inconsistent product quality. To ensure both the efficiency and quality of devolatilization, the fluid must be remixed and then devolatilized multiple times, which is costly and inefficient.

[0004] Therefore, developing a wall-mounted falling film devolatilizer that can reduce the volatile content in the melt through flash evaporation, improve falling film efficiency, reduce equipment volume through sleeves, save equipment layout space, effectively reduce polymer thermal degradation, and improve product performance is obviously of practical significance. Summary of the Invention

[0005] The purpose of this invention is to provide a wall-mounted falling film devolatilizer that can improve falling film efficiency and devolatilization quality.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a wall-mounted falling film devolatilizer, comprising: a devolatilization vessel, a vacuum system, and an internal component located inside the devolatilization vessel. A melt pool is provided between the devolatilization vessel and the internal component. The internal component includes a flash chamber and a sleeve connected sequentially from top to bottom. The sleeve includes a polymer tube and an oil tube sleeved outside the polymer tube. The polymer solution enters the flash chamber through the sleeve from bottom to top, and then falls onto the inner wall of the devolatilization vessel to fall film and flow into the melt pool.

[0007] Preferably, a polymer outlet is provided below the devolatilization reactor, and a melt pump and a pipeline are provided on the polymer outlet. The pipeline is connected to the melt pool, and the melt pump pumps the polymer in the melt pool into the pipeline and out.

[0008] Preferably, the oil pipe includes a heat transfer oil inlet pipe and a heat transfer oil outlet pipe, wherein the heat transfer oil inlet pipe is sleeved on the outside of the polymer pipe, and the heat transfer oil outlet pipe is sleeved on the outside of the heat transfer oil inlet pipe.

[0009] Preferably, the flash chamber includes a shell and a distributor, the distributor being connected to the lower part of the shell and connected to a sleeve.

[0010] Preferably, the cross-sectional area of ​​the distributor increases sequentially from near the sleeve to near the shell, and when the polymer solution enters the flash chamber, the flash evaporation effect causes some volatiles to separate due to the expansion of the flow channel.

[0011] Preferably, the shape of the distributor includes one of a cone, a frustum, a pyramid, or a truncated pyramid.

[0012] Preferably, the shape of the shell includes either a semi-ellipse or a hemisphere.

[0013] Preferably, the shell is provided with a plurality of vents, which are used to discharge the volatile gases separated by the flash chamber and then extracted by the vacuum system.

[0014] Preferably, the distributor has several openings near the housing, which serve as channels for the polymer solution, and a guide tube is connected to the outside of the openings.

[0015] Preferably, the size of the pore diameter is designed according to the viscosity of the polymer solution.

[0016] Preferably, the aperture of the opening includes 1mm to 10mm; including but not limited to 1mm, 2mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 9mm, and 10mm.

[0017] Preferably, the opening consists of several rows of holes arranged around the shape of the distributor, with the spacing between each row of holes being the same, increasing or decreasing from bottom to top, and the spacing between the holes in each row being the same.

[0018] Preferably, the holes are arranged in 1 to 8 rows, and more preferably in 2 to 5 rows.

[0019] Preferably, the devolatilization vessel has a jacketed structure, comprising an upper vessel body and a lower vessel body. The lower vessel body is a columnar structure with an inner diameter smaller than that of the upper vessel body, or the inner diameter of the lower vessel body gradually decreases from near the upper vessel body to far away from the upper vessel body.

[0020] Preferably, the devolatilization vessel includes an inner wall, an outer wall, and hot oil located between the outer wall and the inner wall.

[0021] Preferably, when the lower section of the vessel is a columnar structure with an inner diameter smaller than that of the upper section of the vessel, the upper section of the vessel and the lower section of the vessel are connected by an inclined vessel; the inner diameter of the inclined vessel gradually decreases from the inner diameter of the upper section of the vessel to the inner diameter of the lower section of the vessel, and an inclined wall is provided on the inner side of the inclined vessel, which is located below the distributor to receive the polymer solution.

[0022] Preferably, when the inner diameter of the lower section of the vessel gradually decreases from near the upper section to far away from the upper section, an inclined wall is provided on the inner side of the lower section of the vessel, and the inclined wall is located below the distributor to receive the polymer solution.

[0023] Preferably, the length of the inclined wall provided on the inner side of the lower section of the vessel is L, and the angle between the inclined wall provided on the inner side of the lower section of the vessel and the extension line of the upper section of the vessel is α. The value of L is determined according to the viscosity of the polymer solution and the residence time required for the falling film, and the value of α is determined according to the viscosity of the polymer solution and the residence time required for the falling film.

[0024] Preferably, the angle between the inclined wall on the inner side of the lower section of the vessel and the extension line of the upper section of the vessel is α, and the angle of α is 15° to 85°, including but not limited to 15°, 20°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, and 85°.

[0025] The wall-mounted falling film devolatilizer provided by this invention has the following main flow after the polymer solution enters the device: the polymer fluid enters the device from the bottom through the bottom sleeve, enters the top flash chamber for separation, and some volatiles are vaporized and extracted from the system through the vents at the top of the flash chamber via a vacuum system. The polymer solution is distributed by a distributor and falls onto the inclined surface of the tower wall in the form of drop strips to form a film. Under the action of gravity, it flows into the melt pool and is finally discharged from the system by a melt pump.

[0026] Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art:

[0027] 1. This invention integrates polymer pipes and hot oil pipes by setting up a sleeve, connects the shell and distributor in the flash evaporation chamber, and performs falling film through the inner wall of the devolatilization vessel. The overall structure of the equipment is compact and the size is small, saving equipment layout space and improving plant efficiency.

[0028] 2. The present invention flashes the polymer fluid through a flash chamber, allowing the volatiles in the fluid to evaporate from the fluid and be discharged from the device through the flash chamber, thereby reducing the gas content in the fluid. This makes it less likely for the falling strips formed by the fluid in the distributor to break, and the falling film residence time is longer and more controllable.

[0029] 3. In this invention, the devolatilization vessel has a jacketed structure, and the internal hot oil can effectively maintain the polymer temperature on the tower wall, reduce heat loss, and allow the polymer to enter the devolatilization vessel at a lower temperature, effectively reducing the thermal degradation of the polymer and improving product performance. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the overall structure in Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic cross-sectional view of the sleeve in Embodiment 1 of the present invention;

[0033] Figure 3 This is a partial structural diagram of the distributor in Embodiment 1 of the present invention;

[0034] Figure 4 This is a schematic diagram of the overall structure in Embodiment 2 of the present invention.

[0035] Among them, 1. Deviation reactor; 2. Vacuum system; 3. Melt pool; 4. Flash chamber; 5. Shell; 6. Polymer pipe; 7. Polymer outlet; 8. Melt pump; 9. Pipeline; 10. Heat transfer oil inlet pipe; 11. Heat transfer oil outlet pipe; 12. Shell; 13. Distributor; 14. Pore; 15. Opening; 16. Guide pipe; 17. Upper reactor body; 18. Lower reactor body; 19. Inclined reactor body; 20. Inclined wall; 21. Sloping wall. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0038] Example 1

[0039] like Figures 1-3 As shown, this embodiment relates to a wall-mounted falling film devolatilizer, including: a devolatilizer 1, a vacuum system 2, and an internal component located inside the devolatilizer. A melt pool 3 is provided between the devolatilizer and the internal component. The internal component includes a flash chamber 4 and a sleeve 5 connected sequentially from top to bottom. The sleeve includes a polymer tube 6 and an oil tube sleeved outside the polymer tube. The polymer solution enters the flash chamber through the sleeve from bottom to top, and then falls onto the inner wall of the devolatilizer to fall film into the melt pool.

[0040] Furthermore, a polymer outlet 7 is provided below the devolatilization vessel, and a melt pump 8 and a pipe 9 are provided on the polymer outlet. The pipe is connected to the melt pool, and the melt pump pumps the polymer in the melt pool into the pipe and out.

[0041] Furthermore, the oil pipe includes a heat transfer oil inlet pipe 10 and a heat transfer oil outlet pipe 11. The heat transfer oil inlet pipe is sleeved on the outside of the polymer pipe, and the heat transfer oil outlet pipe is sleeved on the outside of the heat transfer oil inlet pipe.

[0042] Furthermore, the flash chamber includes a shell 12 and a distributor 13, the distributor being connected to the lower part of the shell and connected to a sleeve.

[0043] Furthermore, the cross-sectional area of ​​the distributor increases sequentially from near the sleeve to near the shell. When the polymer solution enters the flash chamber, the flash effect is generated due to the expansion of the flow channel, separating some of the volatiles.

[0044] Furthermore, the shape of the distributor includes one of the following: conical, frustum-shaped, pyramidal, or frustum-shaped.

[0045] Furthermore, the shape of the shell includes either a semi-ellipse or a hemispherical shape.

[0046] Furthermore, the shell is provided with a plurality of vents 14, which are used to discharge the volatile gases separated by the flash chamber and then extracted by the vacuum system.

[0047] Furthermore, the distributor is provided with several openings 15 near the housing, the openings serving as channels for the polymer solution, and a guide pipe 16 is connected to the outside of the openings.

[0048] Furthermore, the size of the pore diameter is designed according to the viscosity of the polymer solution.

[0049] Furthermore, the aperture of the opening includes 1mm to 10mm; including but not limited to 1mm, 2mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 9mm, and 10mm.

[0050] Furthermore, the opening consists of several rows of holes arranged around the shape of the distributor, with the spacing between each row of holes being the same, increasing or decreasing sequentially from bottom to top, and the spacing between the holes in each row being the same.

[0051] Furthermore, the holes are arranged in 1 to 8 rows, and more preferably in 2 to 5 rows.

[0052] Furthermore, the devolatilization vessel has a jacketed structure, comprising an upper vessel body 17 and a lower vessel body 18.

[0053] Furthermore, the devolatilization vessel includes an inner wall, an outer wall, and hot oil located between the outer wall and the inner wall.

[0054] In this embodiment, the lower section of the vessel is a columnar structure with an inner diameter smaller than that of the upper section of the vessel. The upper section of the vessel and the lower section of the vessel are connected by an inclined vessel 19. The inner diameter of the inclined vessel gradually decreases from the inner diameter of the upper section of the vessel to the inner diameter of the lower section of the vessel. An inclined wall is provided on the inner side of the inclined vessel. The inclined wall 20 is located below the distributor to receive the polymer solution.

[0055] The wall-mounted falling film devolatilizer provided by this invention has the following main flow after the polymer solution enters the device: the polymer fluid enters the device from the bottom through the bottom sleeve, enters the top flash chamber for separation, and some volatiles are vaporized and extracted from the system through the vents at the top of the flash chamber via a vacuum system. The polymer solution is distributed by a distributor and falls onto the inclined surface of the tower wall in the form of drop strips to form a film. Under the action of gravity, it flows into the melt pool and is finally discharged from the system by a melt pump.

[0056] Example 2

[0057] This embodiment is based on the above embodiment 1, and the similarities with the above embodiment will not be repeated.

[0058] like Figure 4As shown, in this embodiment, the inner diameter of the lower section of the vessel gradually decreases from near the upper section of the vessel to away from the upper section of the vessel. An inclined wall 21 is provided on the inner side of the lower section of the vessel, and the inclined wall is located below the distributor to receive the polymer solution.

[0059] Furthermore, the length of the inclined wall set inside the lower section of the vessel is L, and the angle between the inclined wall set inside the lower section of the vessel and the extension line of the upper section of the vessel is α. The value of L is determined according to the viscosity of the polymer solution and the residence time required for the falling film, and the value of α is determined according to the viscosity of the polymer solution and the residence time required for the falling film.

[0060] Furthermore, the angle between the inclined wall on the inner side of the lower section of the vessel and the extension line of the upper section of the vessel is α, and the angle of α is 15° to 85°, including but not limited to 15°, 20°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, and 85°.

[0061] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wall-mounted falling film devolatilizer, Its characteristics are: It includes: a devolatilization vessel, a vacuum system, and internal components located inside the devolatilization vessel. A melt pool is provided between the devolatilization vessel and the internal components. The internal components include a flash chamber and a sleeve connected sequentially from top to bottom. The sleeve includes a polymer tube and an oil tube sleeved outside the polymer tube. The polymer solution enters the flash chamber through the sleeve from bottom to top, and then falls onto the inner wall of the devolatilization vessel to fall film and flow into the melt pool. The oil pipe includes a heat transfer oil inlet pipe and a heat transfer oil outlet pipe. The heat transfer oil inlet pipe is sleeved on the outside of the polymer pipe, and the heat transfer oil outlet pipe is sleeved on the outside of the heat transfer oil inlet pipe. The flash chamber includes a shell and a distributor, the distributor being connected to the lower part of the shell and connected to a sleeve; The cross-sectional area of ​​the distributor increases gradually from the sleeve to the shell. When the polymer solution enters the flash chamber, the expansion of the flow channel causes a flashing effect that separates some of the volatiles. The shell is provided with a number of air holes, which are used to discharge the volatile gases separated by the flash evaporation chamber and then extracted by the vacuum system; The distributor has several openings near the housing, which serve as channels for the polymer solution, and a guide tube is connected to the outside of the openings.

2. The wall-mounted falling film devolatilizer according to claim 1, characterized in that, The size of the pore diameter is designed according to the viscosity of the polymer solution, and the pore diameter includes 1mm to 10mm.

3. The wall-mounted falling film devolatilizer according to claim 1, characterized in that, The devolatilization vessel has a jacketed structure, with hot oil disposed between the outer and inner walls. It includes an upper vessel body and a lower vessel body. The lower vessel body is a columnar structure with an inner diameter smaller than that of the upper vessel body, or the inner diameter of the lower vessel body gradually decreases from near the upper vessel body to away from the upper vessel body.

4. The wall-mounted falling film devolatilizer according to claim 3, characterized in that, When the lower section of the vessel is a columnar structure with an inner diameter smaller than that of the upper section of the vessel, the upper and lower sections of the vessel are connected by an inclined vessel. The inner diameter of the inclined vessel gradually decreases from the inner diameter of the upper section to the inner diameter of the lower section. An inclined wall is provided on the inner side of the inclined vessel, and the inclined wall is located below the distributor to receive the polymer solution.

5. A wall-mounted falling film devolatilizer according to claim 3, characterized in that, As the inner diameter of the lower section of the vessel gradually decreases from near the upper section to far away from the upper section, an inclined wall is provided on the inner side of the lower section of the vessel. The inclined wall is located below the distributor to receive the polymer solution.

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