A continuous melt polymer heating falling film light ends stripper

Abstract

The utility model provides a kind of for continuous melt polymer heating falling film light removal evaporator, including several sequentially connected light removal evaporator;Light removal evaporator includes heater, devolatilizer body;The bottom of heater is communicated with the upper portion of devolatilizer body, and the upper portion of devolatilizer body is connected with vacuum system;Grid plate inner component assembly is equipped in devolatilizer body;Polymer passes through heater, and polymer melts and forms pull strip to enter devolatilizer body, and light component is collected into vacuum system by kettle top evacuation pipe, and the bottom of devolatilizer body obtains polymer after light removal.The utility model has beneficial effect: material stays in devolatilizer time distribution is more uniform;Material enters grid plate structure by gravity, and evenly distributed to form film, from top to bottom flow into layer grid plate, and film-forming element is grid plate of parallel angle strip composition;Material has greater mass transfer specific surface area and better interface renewal performance in grid plate inner component.

Description

Technical Field

[0001] This utility model belongs to the field of polymer chemical equipment technology, and in particular relates to an evaporator for heating and removing light particles from continuous melt polymers. Background Technology

[0002] Removing unreacted monomers, residual solvents, and other small molecule light components from the system during polymer production is an essential stage in the polymerization process, and this process is called polymer delighting.

[0003] Existing continuous-feed polymer light component removal systems have the following problems: low monomer removal efficiency, high reactor energy consumption, and a tendency to clog pipes or affect pumps and heat exchangers in subsequent production processes. Furthermore, the presence of monomers leads to insufficient cross-linking within the polymer network, reducing the yield of high-quality products.

[0004] Mass transfer processes in high-viscosity systems require specialized separation equipment, and materials are prone to clogging pipes or adhering to the system.

[0005] Existing devolatilizers may create dead zones in the system, causing some material to get stuck in the pipes and affecting devolatilization efficiency. Utility Model Content

[0006] In view of this, the present invention aims to provide a continuous melt polymer heating falling film delighting evaporator to solve at least one technical problem in the prior art.

[0007] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0008] A continuous melt polymer heating falling film delighting evaporator includes several delighting evaporators connected in sequence;

[0009] The light evaporator includes a heater and a devolatilizer body;

[0010] The bottom of the heater is connected to the upper part of the devolatilizer body, and the upper part of the devolatilizer body is connected to the vacuum system; the devolatilizer body is equipped with a grid plate internal component assembly.

[0011] The polymer is heated and melted to form a strip that enters the devolatilizer body. The light components are collected through the top vent pipe and enter the vacuum system. The bottom of the devolatilizer body yields the polymer after light component removal.

[0012] Furthermore, several grid plate internal components are arranged in parallel inside the devolatilizer body, and the bottom of the devolatilizer body is connected to the polymer outlet pipe;

[0013] A gap is left between the internal components of two adjacent grid plates;

[0014] The central area of ​​the grid internal components assembly has a channel;

[0015] From top to bottom, the area of ​​the central region channel of the grid internal components decreases sequentially.

[0016] Furthermore, the grid plate internal component assembly includes a plurality of grid plates; the plurality of grid plates are connected in sequence in a polygonal distribution, and the edges of the plurality of grid plates form a polygonal channel; the grid plates are provided with a plurality of through holes;

[0017] Preferably, each grid internal assembly includes four grids connected in sequence; the edges of the four grids form a rectangular channel.

[0018] Furthermore, from top to bottom, the distribution density of through holes on the grid internal components decreases sequentially;

[0019] Preferably, from top to bottom, the area of ​​the polygonal region enclosed by the edge of the grid plate within the internal component assembly of the de-scraper plate gradually decreases;

[0020] Preferably, in two adjacent grid plate internal components, the vertical projection of the edge of the upper grid plate is located on the corresponding lower grid plate.

[0021] Furthermore, the grid internal component assembly is inclined, with the inclination direction facing the central region of the grid internal component assembly.

[0022] Furthermore, the distance between adjacent grid internal components is 40mm~60mm;

[0023] Preferably, the spacing between the through holes of the grid plates of the plurality of grid plate internal components is 90mm~110mm.

[0024] Furthermore, a polymer inlet is provided at the upper part of the devolatilizer body;

[0025] The devolatilizer body is fitted with a devolatilizer jacket, the upper part of the devolatilizer jacket is provided with a jacket heat transfer oil outlet, and the lower part of the devolatilizer jacket is provided with a jacket heat transfer oil inlet.

[0026] Furthermore, the heater is a tube-and-shell type;

[0027] And / or, the tube arrangement is 58°-62°;

[0028] And / or, the diameter of the heat exchange tubes of the heater is 18mm~20mm;

[0029] Pipe spacing 24mm~26mm;

[0030] And / or, the heat exchange tubes are provided with baffles in the shell side; the baffles are of the single-arch circular type;

[0031] and / or baffle spacing 190-210mm;

[0032] Preferably, the heater has a heat transfer oil outlet at the top and a heat transfer oil inlet at the bottom.

[0033] Furthermore, the upper part of the devolatilizer body is provided with several light component outlet pipes along the circumference, and the devolatilizer body is connected to the vacuum system through the light component outlet pipes.

[0034] Furthermore, a distributor is provided in the body of the devolatilizer at the position corresponding to the polymer inlet, for distributing the polymer onto the uppermost grid internal component assembly;

[0035] Preferably, the split-viewing mirror is disposed on the devolatilizer body and is disposed above the devolatilized polymer outlet.

[0036] Compared with the prior art, the present invention provides a continuous melt polymer heating falling film evaporator for removing light particles, which has the following advantages:

[0037] The residence time of the material in the devolatilizer body is relatively uniform; the material enters the grid structure by gravity, forms a film evenly, and flows from top to bottom into the grid layers. The film-forming element is a grid composed of parallel angle strips; the material has a large mass transfer specific surface area and good interface renewal performance in the grid internals. Attached Figure Description

[0038] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0039] Figure 1 This is a cross-sectional schematic diagram of a continuous melt polymer heating falling film de-lighting evaporator according to an embodiment of the present invention;

[0040] Figure 2 This is a cross-section of a continuous melt polymer heating falling film de-lighting evaporator as described in an embodiment of this utility model.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Polymer inlet; 2. Heater jacket; 3. Heat transfer oil outlet; 4. Heater; 5. Heat exchange tube; 6. Deviation generator jacket; 7. Deviation generator body; 8. Split sight glass; 9. Grid internals; 10. Polymer outlet pipe; 11. Heat transfer oil inlet; 12. Jacket heat transfer oil inlet; 13. Jacket heat transfer oil outlet; 14. Light component outlet pipe; 15. Grid internals assembly. Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments of the present invention can be combined with each other.

[0044] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0045] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0046] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] Example 1

[0048] A continuous melt polymer heating falling film evaporator for removing light components includes several evaporators connected in sequence. Each evaporator includes a heater 4 and a devolatilizer body 7. The bottom of the heater 4 is connected to the top of the devolatilizer body 7, and the top of the devolatilizer body 7 is connected to a vacuum system. The devolatilizer body 7 is equipped with a grid internal assembly. The polymer passes through the heater 4, melts and forms a strip that enters the devolatilizer body 7. The light components are collected through the top vent pipe and enter the vacuum system. The bottom of the devolatilizer body 7 yields the polymer after light component removal.

[0049] Several grid plate internal components are arranged in parallel inside the devolatilizer body 7. The bottom of the devolatilizer body 7 is connected to the polymer outlet pipe 10. There is a gap between two adjacent grid plate internal components. A channel is provided in the central area of ​​the grid plate internal components. From top to bottom, the area of ​​the channel in the central area of ​​the grid plate internal components decreases sequentially.

[0050] The grid plate internal component assembly includes several grid plates; the several grid plates are connected in sequence in a polygonal distribution, and the edges of the several grid plates form a polygonal channel; several through holes are provided on the grid plates; each grid plate internal component assembly includes four grid plates connected in sequence; the edges of the four grid plates form a rectangular channel.

[0051] From top to bottom, the distribution density of through holes on the grid plate internal component assembly decreases sequentially; from top to bottom, the area of ​​the polygonal region enclosed by the grid plate edge within the grid plate internal component assembly gradually decreases; in two adjacent grid plate internal component assemblies, the vertical projection of the edge of the upper grid plate is located on the corresponding lower grid plate, and the grid plate internal component assembly is inclined, with the inclination direction facing the central area of ​​the grid plate internal component assembly.

[0052] The distance between adjacent grid plate internal components is 40mm~60mm, and the spacing between the through holes of the grid plates of several grid plate internal components is 90mm~110mm. The upper part of the devolatilizer body 7 is provided with a polymer inlet 1, and a devolatilizer jacket 6 is fitted on the devolatilizer body 7. The upper part of the devolatilizer jacket 6 is provided with a jacket heat transfer oil outlet 133, and the lower part of the devolatilizer jacket 6 is provided with a jacket heat transfer oil inlet 12.

[0053] Heater 4 is a tube-and-tube type, with the tubes arranged at 60°.

[0054] The diameter of the heat exchange tube 5 of heater 4 is 20mm;

[0055] The tube spacing is 25mm, and the shell side of heat exchange tube 5 is equipped with baffles; the baffles are of the single-arch circular type.

[0056] The baffle spacing is 190-210mm; the upper part of the heater 4 is provided with a heat transfer oil outlet 3, and the lower part of the heater 4 is provided with a heat transfer oil inlet 11.

[0057] The upper part of the devolatilizer body 7 is provided with several light component outlet pipes 14 along the circumference. The devolatilizer body 7 is connected to the vacuum system through the light component outlet pipes 14. A distributor is provided inside the devolatilizer body 7 at the position corresponding to the polymer inlet 1, which is used to distribute the polymer to the grid internal component assembly located at the top. The split sight glass 8 is provided on the devolatilizer body 7 and is located above the devolatilized polymer outlet.

[0058] The materials extruded from the polymerization reactor usually contain residual low-molecular-weight volatile substances, such as unreacted monomers, oligomers formed after polymerization, reaction byproducts, or solvents. These components can affect the quality of the final product.

[0059] The light component removal evaporator of this embodiment is used for polylactic acid (PLA) light component removal. The PLA obtained from the reaction enters the inlet of heater 4 through polymer inlet 1. After heat exchange with heat transfer oil, the polymer melt is extruded through heat exchange tube 5 and forms a strip-shaped fluid under gravity. During the flow, the fluid gradually becomes thinner and falls onto the grid plate internals 9 of the lower devolatilizer, forming a falling film flow. PLA stays on the grid plate, and the light components are removed in a vacuum environment. The devolatilized material is collected through the bottom feed pipe and sent to the next process, ensuring that the overall residence time of the material in the devolatilizer body 7 is maintained at 5 minutes. The heat of the entire system is provided by a dedicated heat transfer oil mold temperature controller; the vacuum of the entire system is provided by a dedicated vacuum pump. The light component removal efficiency of PLA is 95%.

[0060] Example 2

[0061] This embodiment provides a light-removal evaporator for continuous melt polymer heating falling film. The difference from Embodiment 1 is that two light-removal evaporators are set up in sequence. It is used for light removal in the polylactic acid preparation process, and the light removal effect is 99%.

[0062] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A continuous melt polymer heating falling film evaporator for removing light particles, characterized in that: Includes several light-removing evaporators connected in sequence; The light evaporator includes a heater and a devolatilizer body; The bottom of the heater is connected to the upper part of the devolatilizer body, and the upper part of the devolatilizer body is connected to the vacuum system; the devolatilizer body is equipped with a grid plate internal component assembly. The polymer is heated and melted to form a strip that enters the devolatilizer body. The light components are collected through the top vent pipe and enter the vacuum system. The bottom of the devolatilizer body yields the polymer after light component removal.

2. The continuous melt polymer heating falling film evaporator for removing light particles according to claim 1, characterized in that: Several grid plate internal components are arranged in parallel inside the devolatilizer body, and the bottom of the devolatilizer body is connected to the polymer outlet pipe; A gap is left between the internal components of two adjacent grid plates; The central area of ​​the grid internal components assembly has a channel; From top to bottom, the area of ​​the central region channel of the grid internal components decreases sequentially.

3. The continuous melt polymer heating falling film evaporator for removing light particles according to claim 2, characterized in that: The grid plate internal component assembly includes several grid plates; the several grid plates are connected in sequence in a polygonal distribution, and the edges of the several grid plates form a polygonal channel; several through holes are provided on the grid plates.

4. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 3, characterized in that: Each grid internal component assembly includes four grids connected in sequence; the edges of the four grids form a rectangular channel.

5. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 3, characterized in that: From top to bottom, the distribution density of through holes on the grid internal components decreases sequentially.

6. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 5, characterized in that: From top to bottom, the area of ​​the polygonal region enclosed by the edge of the grid plate within the internal component of the de-scraping plate gradually decreases.

7. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 5, characterized in that: In two adjacent grid plate internal components, the vertical projection of the edge of the upper grid plate is located on the corresponding lower grid plate.

8. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 2, characterized in that: The grid internal component assembly is inclined, with the inclination direction facing the central region of the grid internal component assembly.

9. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 2, characterized in that: The distance between adjacent grid internal components is 40mm~60mm.

10. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 9, characterized in that: The spacing between the through holes of the grid plates in several grid plate internal components is 90mm~110mm.

11. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 1, characterized in that: A polymer inlet is provided at the top of the devolatilizer body; The devolatilizer body is fitted with a devolatilizer jacket, the upper part of the devolatilizer jacket is provided with a jacket heat transfer oil outlet, and the lower part of the devolatilizer jacket is provided with a jacket heat transfer oil inlet.

12. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 1, characterized in that: The heater is a tube-and-shell type; And / or, the tube arrangement is 58°-62°; And / or, the diameter of the heat exchange tubes of the heater is 18mm~20mm; Pipe spacing 24mm~26mm; And / or, the heat exchange tubes are provided with baffles in the shell side; the baffles are of the single-arch circular type; And / or baffle spacing 190-210mm.

13. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 12, characterized in that: The heater has a heat transfer oil outlet at the top and a heat transfer oil inlet at the bottom.

14. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 1, characterized in that: The upper part of the devolatilizer body has several light component outlet pipes along the circumference, and the devolatilizer body is connected to the vacuum system through the light component outlet pipes.

15. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 14, characterized in that: A distributor is provided at the location corresponding to the polymer inlet within the devolatilizer body, for distributing the polymer onto the uppermost grid internal assembly.

16. A continuous melt polymer heating falling film evaporator for removing light particles according to claim 14, characterized in that: The split sight glass is mounted on the devolatilizer body and positioned above the devolatilized polymer outlet.

Images