Vacuum devolatilization device
By designing a vertical container and a membrane pore structure in the vacuum devolatilizer, the problem of volatile gas interference with the falling film flow of the material was solved, achieving efficient vacuuming and a stable falling film process, thus improving product quality and production efficiency.
Patent Information
- Application Number
- CN202511259536.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-12-12
AI Technical Summary
In existing technologies, during the vacuuming process, the flow of volatile gases in falling film devolatilization equipment interferes with the flow of falling film material, resulting in unstable falling film flow, large differences in vacuum degree, and affecting the uniformity of product quality and devolatilization efficiency, especially for high-viscosity materials.
A vacuum devourer was designed, which adopts a vertical container structure and sets the gas extraction port in the vacuum chamber. It is connected to the gas phase channel pipe through the falling film tube. The film-forming holes are evenly arranged to ensure that the material forms a continuous and uniform film on the inner wall of the falling film tube. Combined with a stirrer and a heat exchange chamber, it achieves efficient vacuuming and heat transfer.
It improves the vacuuming effect, reduces the interference of volatile gases on the falling film flow of materials, and enhances the falling film devolatilization efficiency and product quality stability, making it suitable for industrial scale-up production of high-viscosity materials.
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Figure CN121102953A_ABST
Abstract
Description
[0001] This invention is a divisional application of Chinese invention patent application filed on December 6, 2024, with application number 202411788394.1 and invention title "A Vacuum Deviation Device". Technical Field
[0002] This invention relates to a vacuum devolatilization device used in polymer devolatilization, polymer melt reaction preparation, spinning solution degassing, and solution concentration, and belongs to the field of chemical production equipment. Background Technology
[0003] Polymers such as polyethylene terephthalate (PET), polyamide 6 (PA6), polybutylene succinate (PBS), polyamide 66 (PA66), polybutylene terephthalate (PBT), polypropylene terephthalate (PTT), polyethylene naphthalate (PEN), polycarbonate (PC), and polylactic acid (PLA) inevitably retain small-molecule monomers or generate small-molecule byproducts during melt polymerization, such as ethylene glycol and water in PET, and caprolactam in PA6. In solution spinning of polyacrylonitrile, polyimide, etc., air bubbles in the spinning solution must be removed to ensure smooth spinning. The preparation of these polymer materials necessitates a devolatilization process to remove small molecules or air bubbles. This process involves extremely high dynamic viscosity of the materials, sometimes changing by orders of magnitude during the process, making material flow and mixing very difficult and resulting in low heat and mass transfer efficiency.
[0004] Previously, for falling film devolatilization equipment, the vertical container, with its large space containing multiple falling film tubes, employed a vacuum method by installing an extraction port on one side of the container shell. For external falling film, this vacuum method caused the following problems: the shear force exerted by the volatile gas flow on the liquid film surface on different falling film tubes varied, affecting the stability of the material's falling film flow; and the increased difference in vacuum levels at different locations of the falling film tubes affected the uniformity of the devolatilization product's quality. For internal falling film, as the material fell from top to bottom on the falling film tubes, the viscosity gradually increased and the volatile concentration gradually decreased, making the removal of residual volatiles more difficult. Furthermore, the large amount of volatiles moving downwards further inhibited the removal efficiency of residual volatiles; and the increased difference in vacuum levels at different locations of the falling film tubes also affected the uniformity of the devolatilization product's quality. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a vacuum devolatilizer that can improve the vacuuming effect and reduce the interference of volatile gases on the falling film flow of materials, while also having a compact internal structure and being easy to scale up industrially. To this end, this invention adopts the following technical solution:
[0006] A vacuum devolatilizer includes a vertical container with an exhaust port and a material inlet. A melt pressure chamber is located at the top of the container and is connected to the material inlet. The devolatilizer is characterized by having at least one falling film tube, the inner wall of which serves as the material falling film contact surface. Inside the container, a vacuum chamber is located above the melt pressure chamber, and the exhaust port is located within the vacuum chamber. A gas phase channel tube is located at the upper end of the falling film tube, passing through the melt pressure chamber and communicating with the vacuum chamber.
[0007] Based on the above technical solutions, the present invention may also employ the following further technical solutions, or combine these further technical solutions:
[0008] The bottom plate of the melt pressure chamber is provided with a connection hole for connecting the upper end of the falling film tube. A plurality of film-laying holes are arranged around the inner side of the upper end of the falling film tube in the circumferential direction. The film-laying holes connect the melt pressure chamber and the falling film tube, and the film-laying ring forming the film-laying holes is connected to the gas phase channel tube. The falling film tube is connected to the film-laying ring.
[0009] A feeding chamber is provided at the bottom of the container, and the feeding chamber is provided with a material outlet; the vertical container is provided with a heat exchange chamber between the melt pressure chamber and the feeding chamber, and the falling film tube passes through the heat exchange chamber and is connected to the feeding chamber at its lower end.
[0010] The inscribed circle diameter of the falling film tube is 50–300 mm. When the falling film tube is a circular tube, the inscribed circle diameter is the inner diameter of the circular tube; when it is a shaped tube, the inscribed circle diameter is the inscribed circle diameter of the inner wall of the shaped tube.
[0011] The irregularly shaped tube is preferably a regular polygonal tube or a multi-petaled plum blossom-shaped tube. Among the regular polygonal tubes, the preferred shapes are regular square, regular pentagon, regular hexagon, regular heptagon, regular octagon, regular nonagon, and regular decagon. Among the multi-petaled plum blossom-shaped tubes, the preferred shapes are four-petaled plum blossom-shaped, five-petaled plum blossom-shaped, six-petaled plum blossom-shaped, seven-petaled plum blossom-shaped, eight-petaled plum blossom-shaped, nine-petaled plum blossom-shaped, and ten-petaled plum blossom-shaped.
[0012] When the dynamic viscosity of the material is 0.1–10 Pa·s, the intangent diameter of the falling film tube is 50–100 mm; or, when the dynamic viscosity of the material is 10–100 Pa·s, the intangent diameter of the falling film tube is 60–180 mm; or, when the dynamic viscosity of the material is 100–1000 Pa·s, the intangent diameter of the falling film tube is 80–250 mm; or, when the dynamic viscosity of the material is 1000–10000 Pa·s, the intangent diameter of the falling film tube is 120–300 mm.
[0013] The membrane holes are evenly arranged around the inner wall of the falling film tube in the circumferential direction. Each membrane hole is not interconnected with the others. The interval M between adjacent membrane holes is 1 to 20 mm. The number of membrane holes corresponding to each falling film tube is greater than or equal to 10.
[0014] The falling film tube has a length of 1 to 20 m. More preferably, the length of the falling film tube is 3 to 12 m.
[0015] The diameter of the inscribed circle of the membrane hole is 2-15 mm, and the length-to-diameter ratio (L / D) of the membrane hole is 2-15. Further, the diameter of the inscribed circle of the membrane hole is preferably 3-12 mm, and the length-to-diameter ratio is preferably 5-15; each membrane hole has the same size and shape.
[0016] The membrane hole can be a round hole, a non-round hole, or a hole formed by a groove and the inner wall of the falling film tube; when the membrane hole is a round hole, the diameter of the inscribed circle of the membrane hole is the diameter of the round hole; when the membrane hole is a non-round hole, the diameter of the inscribed circle of the membrane hole is the diameter of the largest inscribed circle of the non-round hole.
[0017] The melt pressure in the melt pressure chamber is 10 to 1000 kPa; further, the melt pressure in the melt pressure chamber is preferably 50 to 600 kPa.
[0018] When the membrane hole is round or non-round, the shortest distance X from the inner wall of the membrane hole to the inner wall of the falling film tube is less than or equal to 20mm. This can be matched with the hole spacing and the length-to-diameter ratio of the membrane hole, so that all the material flowing out of the membrane hole can be drawn to the inner wall of the falling film tube to form a continuous and uniform film.
[0019] The heat exchange chamber is the shell side between the melt pressure chamber and the feeding chamber, and is equipped with a heat medium inlet and a heat medium outlet.
[0020] The bottom shell of the falling film devolatilizer, i.e. the feeding chamber, is equipped with a stirrer for homogenizing the material after falling film devolatilization.
[0021] For in-tube falling film distribution, there are unique advantages. By designing the membrane perforation structure parameters and falling film tube parameters, it is possible to achieve continuous and stable film distribution of materials with different flow characteristics on the inner wall of the falling film tube on a non-connected perforated membrane distributor while maintaining high volume utilization (surface area per unit volume of falling film tube). This results in small fluctuations in the residence time of the materials during the falling film flow, which is beneficial to improving the quality stability of the falling film product. As a result, production costs can be reduced, and it is easy to scale up industrially.
[0022] This invention provides a vacuuming scheme for devolatilizers employing in-tube falling film processing, which improves the vacuuming effect and reduces the interference of volatile gases on the material's falling film flow. Simultaneously, the internal components are compact and easily scaled up industrially. This invention ensures the volume of the gas phase channel during the material falling film process, enabling efficient removal of large amounts of hot volatile gases from bottom to top, maintaining the vacuum level during the falling film process, and improving the falling film devolatilization efficiency. It is suitable for large-capacity, continuous devolatilization processing of high-viscosity materials. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the falling film devolatilizer provided by the present invention;
[0024] Figure 2 for Figure 1 Local area of the medium falling film devolatilizer ( Figure 1 (Center C) Enlarged view;
[0025] Figure 3 for Figure 1 The NN cross-sectional view of the falling film devolatilizer using the first embodiment of the combination of film distribution holes and falling film tubes;
[0026] Figure 4 for Figure 1 NN cross-sectional view of the falling film devolatilizer using the second embodiment of the combination of film holes and falling film tubes;
[0027] Figure 5 for Figure 1 NN cross-sectional view of the falling film devolatilizer using the third embodiment of the combination of film holes and falling film tubes;
[0028] Figure 6 for Figure 1 The NN cross-sectional view of the falling film devolatilizer using the fourth embodiment of the combination of film holes and falling film tubes. Detailed Implementation
[0029] To enhance understanding of the present invention, the following detailed description of the present invention will be provided using combined embodiments. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.
[0030] Example 1, referring to Figure 1 , 2 3
[0031] This embodiment provides a vacuum devourer, such as Figure 1 , 2As shown, it adopts a vertical container, including a heat exchange chamber 5, a melt pressure chamber 4 located above the heat exchange chamber 5, a feeding chamber 10 located below the heat exchange chamber 5, and a vacuum chamber 2 located above the melt pressure chamber 4. A falling film tube 6 is vertically installed inside the heat exchange chamber 5. A gas phase channel tube 18 is provided at the upper end of the falling film tube 6. The gas phase channel tube 18 passes vertically through the melt pressure chamber 4 and communicates with the vacuum chamber 2. The vacuum chamber 2 is provided with an exhaust port 19. A film distribution hole 15 is provided at the intersection of the falling film tube 6 and the gas phase channel tube 18. The film distribution hole 15 connects the melt pressure chamber 4 and the falling film tube 6. The film distribution hole 15 is evenly distributed along the circumferential direction of the inner wall of the falling film tube. The film distribution ring 16 forming the film distribution hole 15 is connected to the gas phase channel tube 18. The falling film tube 6 and the film distribution ring 16 are connected.
[0032] The top plate 17 of the melt pressure chamber 4 serves as a partition between the vacuum chamber 2 and the melt pressure chamber 4. The bottom plate 14 of the melt pressure chamber 4 is provided with a connecting hole for connecting the upper end of the falling film tube. The lower part of the falling film tube is fixed on the falling film tube fixing bed 9. A feeding chamber 10 is provided at the bottom of the container, with the falling film tube fixing bed 9 serving as its top plate. The feeding chamber 10 is provided with a material outlet 11. The vertical container is provided with a heat exchange chamber 5 between the melt pressure chamber 4 and the feeding chamber 10. The falling film tube 6 passes through the heat exchange chamber 5, and its lower end is connected to the feeding chamber 10.
[0033] The shell of the vertical container consists of a cylindrical main tank body, a tank top, and a roughly conical bottom, wherein the tank top and the tank bottom are connected to the main tank body via flanges 3 and 8.
[0034] Multiple falling film tubes are vertically installed inside the devolatilizer. The falling film tubes are round tubes with an inner tangent diameter of 250mm.
[0035] The membrane hole 15 is formed by the semi-circular groove on the membrane ring and the inner wall of the falling film tube. The maximum inscribed circle P diameter is 6mm, the length-to-diameter ratio of the membrane hole length L to the inscribed circle diameter D is 9, the shortest distance X from the inner wall surface of the membrane hole to the inner wall surface of the falling film tube is 0mm, and the membrane holes are evenly distributed along the circumference of the inner wall surface of the falling film tube. Figure 3 As shown.
[0036] The devolatilizer is equipped with a heat transfer system, including the heat exchange chamber 5, the heat medium inlet 7, and the heat medium outlet 13, to ensure the heat required for the material devolatilization process.
[0037] The bottom shell of the devolatilizer is equipped with an agitator 12 for homogenizing materials, and the agitation power is transmitted from the bottom.
[0038] Example 2, refer to Figure 1 , 2 4
[0039] In this embodiment, the membrane hole is a round hole, the falling film tube is a round tube, and the diameter of the inscribed circle of the falling film tube is 150mm.
[0040] The membrane hole 15 is a circular hole on the membrane ring, with a diameter of 5mm. The length L of the membrane hole has a length-to-diameter ratio of 12 to the diameter D of the inscribed circle. The shortest distance X from the inner wall of the membrane hole to the inner wall of the falling film tube is 5mm. The membrane holes are evenly distributed along the circumference of the inner wall of the falling film tube. Figure 4 As shown, the rest is the same as in Example 1.
[0041] Example 3, referring to Figure 1 , 2 4
[0042] In this embodiment, the membrane hole is a round hole, the falling film tube is a round tube, and the diameter of the inscribed circle of the falling film tube is 110mm.
[0043] The membrane hole 15 is a circular hole on the membrane ring, with a diameter of 5mm. The length L of the membrane hole and the length-to-diameter ratio of the inscribed circle diameter D are 10. The shortest distance X from the inner wall of the membrane hole to the inner wall of the falling film tube is 4mm. The membrane holes are evenly distributed along the circumference of the inner wall of the falling film tube. Figure 4 As shown, the rest is the same as in Example 1.
[0044] Example 4, refer to Figure 1 , 2 5
[0045] In this embodiment, the membrane hole is a round hole, the falling film tube is a regular hexagonal tube, and the diameter of the inscribed circle of the falling film tube is 140mm.
[0046] The membrane hole 15 is a circular hole on the membrane ring, with a diameter of 6mm. The length L of the membrane hole and the length-to-diameter ratio of the inscribed circle diameter D are 10. The shortest distance X from the inner wall of the membrane hole to the inner wall of the falling film tube is 5mm. The membrane holes are evenly distributed along the circumference of the inner wall of the falling film tube. Figure 5 As shown, the rest is the same as in Example 1.
[0047] Example 5, refer to Figure 1 , 2 6
[0048] In this embodiment, the membrane hole is a round hole, the falling film tube is a six-lobed plum blossom-shaped tube, and the inner diameter of the falling film tube is 230mm.
[0049] The membrane hole 15 is a circular hole on the membrane ring, with an inscribed circle diameter of 6mm. The length L of the membrane hole and the length-to-diameter ratio D of the inscribed circle are 9. The shortest distance X from the inner wall of the membrane hole to the inner wall of the falling film tube is 3mm. The membrane holes are evenly distributed along the circumference of the inner wall of the falling film tube. Figure 6 As shown, the rest is the same as in Example 1.
[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various modifications and alterations without departing from the principles of the present invention, and these modifications and alterations should also be considered within the scope of protection of the present invention.
Claims
1. A vacuum devourer, comprising a vertical container, the container being provided with an air extraction port (19) and a material inlet (1), and a melt pressure chamber (4) being provided at the upper part of the container, the melt pressure chamber (4) being connected to the material inlet (1); characterized in that, The devolatilizer is provided with at least one falling film tube (6), the inner wall surface of the falling film tube (6) is the material falling film flow contact surface, and a vacuum chamber (2) is provided above the melt pressure chamber (4) in the container, and the exhaust port (19) is provided in the vacuum chamber (2); a gas phase channel pipe (18) is provided at the upper end of the falling film tube (6), the gas phase channel pipe (18) passes through the melt pressure chamber (4) and communicates with the vacuum chamber (2).
2. The falling film devolatilizer as described in claim 1, characterized in that, The bottom plate (14) of the melt pressure chamber (4) is provided with a connection hole for connecting the upper end of the falling film tube (6). A plurality of film-laying holes (15) are arranged around the inner side of the upper end of the falling film tube (6) in the circumferential direction. The film-laying holes (15) connect the melt pressure chamber (4) and the falling film tube (6). The film-laying ring (16) forming the film-laying holes (15) is connected to the gas phase channel tube (18). The falling film tube (6) is connected to the film-laying ring (16).
3. The falling film devolatilizer as described in claim 1, characterized in that, A feeding chamber (10) is provided at the bottom of the vertical container, and a material outlet (11) is provided in the feeding chamber (10); a heat exchange chamber (5) is provided between the melt pressure chamber (4) and the feeding chamber (10) in the vertical container, and a falling film pipe (6) passes through the heat exchange chamber (5), and the lower end of the falling film pipe (6) is connected to the feeding chamber (10).
4. The falling film devolatilizer as described in claim 1, characterized in that, The falling film tube (6) is a round tube or a special-shaped tube, and the diameter of the inscribed circle of the falling film tube (6) is 50 to 300 mm.
5. The falling film devolatilizer as described in claim 2, characterized in that, The diameter of the inscribed circle of the membrane hole is 2-15 mm, and the length-to-diameter ratio L / D of the membrane hole is 2-15.
6. The falling film devolatilizer as described in claim 2, characterized in that, The membrane hole (15) is a round hole or a non-round hole or a hole formed by a groove and the inner wall of the falling film tube; the shortest distance X from the inner wall of the membrane hole (15) to the inner wall of the falling film tube is less than or equal to 20 mm.
7. The falling film devolatilizer as described in claim 3, characterized in that, The heat exchange chamber (5) is the shell side between the melt pressure chamber (4) and the feeding chamber (10), and is provided with a heat medium inlet (7) and a heat medium outlet (13).
8. The falling film devolatilizer as described in claim 1, characterized in that, The melt pressure in the melt pressure chamber (4) is 10 to 1000 kPa.