CN115920428A - Polymer devolatilization device and polyolefin elastomer devolatilization method - Google Patents
Polymer devolatilization device and polyolefin elastomer devolatilization method Download PDFInfo
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- 229920006124 polyolefin elastomer Polymers 0.000 title claims abstract description 39
- 238000000034 method Methods 0.000 title claims abstract description 24
- 229920000642 polymer Polymers 0.000 title claims abstract description 15
- 239000000463 material Substances 0.000 claims description 28
- 239000000155 melt Substances 0.000 claims description 19
- 238000010438 heat treatment Methods 0.000 claims description 8
- 239000011552 falling film Substances 0.000 claims description 5
- 230000008020 evaporation Effects 0.000 claims description 4
- 238000001704 evaporation Methods 0.000 claims description 4
- 238000007599 discharging Methods 0.000 claims description 2
- 238000000605 extraction Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 239000013589 supplement Substances 0.000 claims description 2
- 239000007787 solid Substances 0.000 description 14
- 239000012855 volatile organic compound Substances 0.000 description 8
- 239000002904 solvent Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 239000000178 monomer Substances 0.000 description 5
- 230000003068 static effect Effects 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000010408 film Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000012452 mother liquor Substances 0.000 description 2
- 230000006911 nucleation Effects 0.000 description 2
- 238000010899 nucleation Methods 0.000 description 2
- 239000002861 polymer material Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000004711 α-olefin Substances 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000010528 free radical solution polymerization reaction Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000003039 volatile agent Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004383 yellowing Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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Abstract
The invention discloses a polymer devolatilization device and a polyolefin elastomer devolatilization method, wherein the device comprises a plurality of devolatilization devices, an inlet of each devolatilization device is provided with an ellipsoidal table-shaped feeding distributor, an inlet of a first-stage devolatilization device is heated by a feeding preheater, and a last-stage devolatilization device is directly heated by introducing steam.
Description
Technical Field
The invention belongs to the technical field of production and processing of high polymer materials, relates to an elastomer devolatilization production technology, and particularly relates to a polymer devolatilization device and a polyolefin elastomer devolatilization method.
Background
Most of polymers at the outlet of a polymerization reactor contain components with low relative molecular mass, such as monomers, solvents, water, byproducts and other volatile components, the content of the volatile components generally reaches 10 to 80 weight percent according to different processes, and the volatile components need to be further removed, so that the requirements of improving the performance and the health of the polymers and the environment and the requirements of recovering the solvents and the monomers and the like are met. With the continuous improvement of safety, environmental protection and health level, the requirements of different application fields on the VOC content in polymer materials are also continuously improved, for example, the acrylonitrile content in food-grade ABS products is required to be lower than 5ppm at most.
The polyolefin elastomer is a random copolymer of ethylene and alpha-olefin catalyzed by metallocene, has excellent weather resistance and chemical resistance, good compatibility with polyolefin, high elasticity of rubber and easy processability of plastic, and has the advantages of lower cost, lighter weight, lower energy consumption and more environmental friendliness. The synthesis generally adopts a solution polymerization process. The polymer solid at the outlet of the reactor only accounts for 8-25wt% of the reaction mother liquor, the incompletely reacted polymerized monomers in the mother liquor comprise ethylene, alpha-olefin and solvent, and then the slurry is conveyed to a devolatilization device behind the reactor to remove the unreacted monomers and solvent. The structural design and the process parameter control of the devolatilizer are the factors which are crucial in relation to the VOC index in the final product of the polyolefin elastomer.
Few patents have been published for devolatilization of polyolefin elastomers. In industry, the widely used polymer devolatilization process includes a falling-film devolatilizer or an in-tube falling-film devolatilizer, etc., and the removal of solvent and monomer is realized by preheating the feeding material and vacuumizing the devolatilizer and continuously updating the interface during the falling of the polymer melt. In order to increase the devolatilization effect by allowing as much volatile components as possible to diffuse away from the constantly renewed interface, it is common in the industry to increase the preheating temperature and the degree of vacuum of the feed as much as possible. However, according to the research of Park and Suh et al, rapid temperature increase or pressure decrease causes the polymer solution to be in a thermodynamically unstable supersaturated state, and bubble nuclei are easily formed at the interface, so that volatile components exist in the form of bubbles. The process of nucleation, growth and collapse of the bubbles becomes the controlling step in the devolatilization process. Only when the bubbles are finally broken, the volatile components in the bubbles can be diffused out, so the bubbling devolatilization process seriously influences the devolatilization effect of the devolatilization device. Therefore, it is desirable to optimize existing devolatilization equipment to improve the interfacial renewal of the melt and to achieve rapid bubble destruction, thereby improving the devolatilization effect.
Disclosure of Invention
The invention aims to provide a device for devolatilizing a polymer, which has the advantages of fast updating of a melt interface, fast breaking of bubbles and high devolatilizing efficiency in the devolatilizing process.
The invention also aims to provide a method for devolatilizing the polyolefin elastomer, which adopts a multi-stage (more than or equal to two stages) static devolatilizing process, has high devolatilizing efficiency, and ensures that the residual volatile organic compounds in the product are less than 2000ppm.
To achieve the above technical object, the present invention provides a devolatilization apparatus comprising: the pre-stage devolatilization device comprises a feeding distributor, a preheater and a devolatilization tank, wherein the feeding distributor is fixed at the top of the preheater, the devolatilization tank is positioned below the preheater, the material enters the preheater through the distributor to be heated, the devolatilization tank is positioned below the preheater and is connected through a flange, a melt feeding pump is positioned at the bottom of the devolatilization tank, and the feeding distributor is provided with an elliptical table-shaped hole;
the ware is waved to last level, the ware is waved in taking off contains feeding distributor, steam inlet pipe, takes off and waves the jar, and the feeding distributor is fixed in the top of pre-heater, the feeding distributing plate is opened there is oval table shape hole, the feeding distributor below is equipped with the steam inlet pipe. According to the difference of specific devolatilization technology, the preceding-stage devolatilization device can be connected in series with the final-stage devolatilization device after one-stage or multi-stage series connection, and the preceding-stage devolatilization device conveys materials to the top of the next-stage devolatilization device through a pipeline by a melt pump.
In some preferred embodiments of the present invention, the elliptical table-shaped holes are uniformly distributed on the feeding distributor in a regular triangle shape, the upper bottom ellipse of the elliptical table is concentric with the lower bottom ellipse, the area of the upper bottom ellipse is larger than that of the lower bottom, and the height of the elliptical table is equal to the thickness of the feeding distribution plate.
Preferably, the center-to-center distance between the upper base ellipses is 1-5 times the major axis of the upper base ellipse.
Preferably, the long axis of the ellipse at the upper bottom of the elliptical truncated cone-shaped hole is 2-8 times of the long axis of the ellipse at the lower bottom, the long axis of the ellipse at the upper bottom is 20-40mm, and the short axes of the ellipse at the upper bottom and the lower bottom are 0.2-5 times of the length of the long axis
Preferably, a circular ring pipe distributor is arranged at the inlet of the steam feeding pipe of the final-stage devolatilization device, the outer diameter of the ring pipe distributor is equal to the diameter of the feeding distribution plate of the final-stage devolatilization device, and circular holes are uniformly formed in the ring pipe.
Preferably, the diameter of the circular holes is 6-12mm, the center distance between any two adjacent circular holes is equal, and the center distance is 3-10 times of the diameter of the circular holes; preferably 3 to 8 times.
Preferably, the ring pipe distributor is 20-100mm below the feed distribution plate.
The invention also provides a devolatilization process of a polyolefin elastomer by using the devolatilization device, which comprises the following steps:
s1: conveying the material at the outlet of the polyolefin elastomer reactor to a pre-devolatilization device for devolatilization;
s2, after the devolatilization in the step S1 is finished, conveying the mixture to a final-stage devolatilization device for devolatilization;
s3: and S2, discharging after the devolatilization is finished.
Further, the step S1 further includes the following steps:
a1: the material enters a feeding distributor at the top of the pre-stage devolatilization device, is uniformly distributed through the distributor and enters a heat exchange tube of a preheater;
a2: polymer melt falling film evaporation is carried out in the heat exchange tube, and a heating medium is arranged outside the tube;
a3: the material flows out from the preheater and enters a devolatilization tank at the bottom, and is subjected to flash evaporation devolatilization in the tank.
Further, the step S2 further includes the following steps:
b1: materials at the outlet of the pre-stage devolatilization device are conveyed to the final-stage devolatilization device by a pump, and the materials enter the devolatilization tank in a falling strip shape after being uniformly distributed by the feeding distributor at the top;
b2: steam is uniformly dispersed into the gas phase space in the tank through the ring pipe distributor, and meanwhile, heating and steam stripping of the falling strips are realized.
B3: the secondary devolatilizer is provided with a pressure control loop for adjusting steam air supplement and air extraction rate of a vacuum pump, and different operating pressures are maintained according to different feeding temperatures and solid holdup rates; steam enters the devolatilizer through the circular pipe distributor to expand instantaneously, and the falling strip material contacts with the steam to produce superheat degree, so that volatile components are removed rapidly under high vacuum condition.
In some preferred embodiments of the invention, the feed is preferably a reactor outlet polyolefin elastomer solution having a polymer solids content of 8 to 25wt%, a volatiles content of 75 to 92wt%, and a feed temperature of 140 ℃ to 160 ℃.
Preferably, the preheater is a single-tube-pass single-shell-pass tubular heat exchanger, hot oil is adopted as a shell-pass heating medium, the inlet temperature of the hot oil is 270-290 ℃, and the outlet temperature of a tube-pass material is 260-280 ℃.
Preferably, the medium inside the pipe is polyolefin elastomer melt, and the heating medium outside the pipe is steam, hot oil or the like.
Preferably, the operating temperature of the pre-stage devolatilizer is 200-240 ℃, the operating pressure is 0.15-0.35MpaG, and the apex angle of the bottom cone of the devolatilizer is 75-90 degrees.
Depending on the series of stages (generally not more than four stages) and the ratio of solvent removal in each stage, the temperature drop of the devolatilizer after preheating in the latter stages is generally within 10 ℃ in terms of the operating temperature of the devolatilizer, i.e., if the operating temperature of the devolatilizer in the former stage is 220 ℃, the devolatilizer in the latter stage is preheated to 240 ℃ by the preheater, and the operating temperature of the devolatilizer in the latter stage is between 230 ℃ and 240 ℃. Preferably, the preheating temperature of the final devolatilizer is 240-260 ℃ and the operating temperature of the intermediate devolatilizers is 230-250 ℃.
Depending on the number of stages in series (generally not more than four stages) and the ratio of solvent removed in each stage, the operating pressure of the last stage of devolatilizer is generally lower than that of the previous stage, typical operating conditions of a four-stage devolatilizer series are: the operating pressure of the first-stage devolatilizer is 0.15-0.35MpaG, the operating pressure of the second-stage devolatilizer is 0-0.1 MpaG, the operating pressure of the third-stage devolatilizer is 10-100 kPaA, and the operating pressure of the last-stage devolatilizer is less than 10kPaA.
Preferably, the material leaving the devolatilizer of the preceding stage has a volatile content of between 5 and 15% by weight and a temperature of between 200 ℃ and 240 ℃.
Preferably, the temperature of the steam of the final-stage devolatilizer is 240-260 ℃, and the pressure is 3-4MpaG;
preferably, the pressure of the final-stage devolatilizer is 0.1-2kpA, and the apex angle of the bottom cone of the devolatilizer is 75-90 degrees.
Preferably, the volatile content of the exit material from the last devolatilizer is less than 2000ppm.
The invention has the following beneficial effects:
1. compared with the uniform circular or grid slit-shaped opening elements in the traditional falling strip or falling film type static devolatilizer, the feeding distributor of the device is provided with the elliptical truncated cone-shaped opening elements with large top and small bottom, and the design has two benefits: on one hand, under the great pressure drop of two sides of the distributor, the materials enter the holes of the elliptical table, the elliptical area of the top part is large and the materials are distributed in a regular triangle shape, so that the materials are uniformly dispersed, in the process of going down along the holes, the hole diameter is smaller and smaller, the flow rate is faster and faster, the updating of the surface of the melt is facilitated, and finally the melt flows out through the small holes at the bottom and is in a fine falling strip shape, so that the removal of volatile matters in the falling process is facilitated; on the other hand, under high vacuum and high superheat degree, bubble nuclei are easily formed on the surface of the melt, but because the opening element is in an oval shape, the growth of the bubble nuclei in the minor axis direction is limited and is not easy to grow, and the included angle between the inner surface of the hole and the horizontal direction is larger than the equilibrium contact angle of the melt, the bubbles generate a yield phenomenon and start to slide, and when the melt flows out of the opening element, the bubbles are rapidly separated from the surface of the melt.
2. On one hand, because the solid content of the melt at the inlet of the last stage reaches 95-99wt%, compared with the viscosity of the inlet of the first stage, the viscosity is obviously increased, and at the moment, the traditional tube type heat exchanger is adopted, the tube is laminar, the heat transfer coefficient is very small, the heat exchange effect is poor, and the steam is adopted for direct contact heating, so that the heat transfer efficiency is high, and the investment of expensive high-viscosity heat exchanger equipment is saved; on the other hand, when high-pressure steam enters the devolatilizer through small holes distributed in an annular pipe, the flow velocity is very high, the volume of the steam is rapidly expanded due to high vacuum, the steam wraps the falling strip when the falling strip descends, and the concentration of volatile components in a gas phase is diluted, so that huge concentration gradients exist in the volatile component melt and the gas phase space, and the removal efficiency of the volatile components is remarkably improved. Meanwhile, the continuous blowing of the steam inhibits the nucleation of bubbles on the surface of the melt and accelerates the separation of the bubbles from the surface of the melt.
By adopting the process, the heat transfer effect is greatly enhanced, the film forming area is increased, the surface updating of a liquid film is promoted, the devolatilization efficiency is improved, and the volatile components in the polyolefin elastomer can be removed to below 2000ppm through two-stage static devolatilization. Meanwhile, the melt is heated more uniformly, so that the phenomena of high local temperature, yellowing and black spots of the material are avoided.
Drawings
FIG. 1 is a schematic flow diagram of a two stage polyolefin elastomer devolatilization process of the present invention;
FIG. 2 is a schematic view of the front stage devolatilizer of the devolatilization apparatus of the present invention;
FIG. 3 is a schematic view of the last stage devolatilizer of the devolatilization apparatus of the present invention;
FIG. 4 is a schematic view of the devolatilizer inlet distributor openings;
fig. 5 is a schematic diagram of the steam feed loop distributor configuration.
Detailed Description
The invention is further described in detail below with reference to the attached drawings and specific examples:
as shown in fig. 1, in the embodiment of the present invention, the devolatilization system used comprises a primary devolatilizer D01, a primary devolatilized melt feed pump P01; a secondary devolatilizer D02 and a secondary melt pump P02. The top of the first-stage devolatilization preheater E01 is provided with a feeding distributor, a material distributor is also arranged in the second-stage devolatilization device D02, and the polyolefin elastomer material flows along the direction from top to bottom.
As shown in fig. 2 and 4, one-level devolatilization device D01 comprises one-level feeding distributor 1, preheater 2 and one-level devolatilization tank 3, one-level feeding distributor 1 is fixed in the top of preheater 2, one-level devolatilization tank 3 is located the below of preheater is connected through the flange, one-level melt feeding pump P01 is located the bottom of devolatilization tank, one-level feeding distributor 1 has been seted up with ellipsoid table-shaped hole, ellipsoid table-shaped hole is in be regular triangle evenly distributed on the feeding distribution plate ware, ellipsoid table upper end ellipse and lower bottom ellipse are concentric, and the upper end elliptical area is greater than lower bottom, ellipsoid table height with feeding distributor thickness equals.
As shown in fig. 3 and 4, the second-stage devolatilizer D02 comprises a second-stage feeding distributor 4, a steam feeding pipe 2 and a second-stage devolatilizing tank 6, wherein the second-stage feeding distributor 4 is fixed on the top of the devolatilizer, the second-stage feeding distributor 4 is provided with an elliptical table-shaped hole, and the steam feeding pipe 2 is arranged below the feeding distributor. As shown in FIG. 5, the steam feed pipe inlet of the secondary devolatilizer was equipped with a circular loop distributor.
Example 1:
in this example, the flow rate of the polyolefin elastomer solution entering the first-stage devolatilizer was 200kg/h, the solid content was 8wt%, and the temperature was 140 ℃. The first-stage preheater is heated by hot oil at 270 ℃, the temperature of the polyolefin elastomer solution at the outlet of the first-stage preheater is 260 ℃, the operating temperature of the first-stage devolatilizer is 240 ℃, and the operating pressure is 0.35MpaG.
The feeding distributor of the first-stage devolatilization device is provided with 150 holes, the long axis of the ellipse at the top of the elliptical table is 20mm, the short axis is 10mm, the center distance is 100mm, the long axis of the ellipse at the bottom is 5mm, the short axis is 2.5mm, and the cone angle at the bottom of the first-stage devolatilization device is 75 degrees.
The polyolefin elastomer solution at the inlet of the secondary devolatilizer had a solids content of 95 wt.% (i.e., a volatile content of 5 w.%) and a feed temperature of 220 ℃. The second-stage devolatilizer was heated with 3MpaG and steam at 240 ℃. The operating temperature of the secondary devolatilizer was 235 ℃ and the operating pressure was 2kpa, with an outlet polyolefin elastomer melt temperature of 235 ℃ and an outlet melt VOC content of 1925ppm.
The feeding distributor of the secondary devolatilizer is provided with 150 holes, the major axis of the ellipse at the top of the elliptical table is 16mm, the minor axis is 8mm, the center distance is 40mm, the major axis of the ellipse at the bottom is 4mm, the minor axis is 2mm, and the apex angle of the bottom cone of the devolatilizer is 75 degrees.
The number of the circular holes formed in the steam feeding circular pipe is 40, the diameter of the circular holes is 6mm, and the center distance between every two adjacent circular holes is 18mm.
Example 2:
in this example, the flow rate of the polyolefin elastomer solution entering the first-stage devolatilizer was 300kg/h, the solid content was 15wt%, and the temperature was 150 ℃. The first-stage preheater is heated by hot oil at 285 ℃, the temperature of the polyolefin elastomer solution at the outlet of the first-stage preheater is 270 ℃, the operating temperature of the first-stage devolatilizer is 240 ℃, and the operating pressure is 0.25MpaG.
220 openings are formed in a feeding distributor of the primary devolatilizer, the long axis of the ellipse at the top of the elliptical table is 24mm, the short axis of the ellipse is 7.2mm, the center distance is 72mm, the long axis of the ellipse at the bottom of the elliptical table is 4mm, the short axis of the ellipse is 1.6mm, and the cone angle at the bottom of the primary devolatilizer is 80 degrees.
The polyolefin elastomer solution at the inlet of the secondary devolatilizer had a solids content of 90 wt.% (i.e., a volatile content of 10 w.%) and a feed temperature of 240 ℃. The second-stage devolatilizer was heated by introducing 3.5MpaG of steam at 245 ℃. The operating temperature of the secondary devolatilizer was 243 ℃ and the operating pressure was 0.5kpa, with an outlet polyolefin elastomer melt temperature of 243 ℃ and an outlet VOC content of 1682ppm.
The feeding distributor of the secondary devolatilization device is provided with 150 holes, the long axis of the ellipse at the top of the elliptical table is 16mm, the short axis is 8mm, the center distance is 32mm, the long axis of the ellipse at the bottom is 4mm, the short axis is 1.6mm, and the cone angle at the bottom of the primary devolatilization device is 80 degrees.
The number of the circular holes formed in the steam feeding circular pipe is 34, the diameter of the circular holes is 8mm, and the center distance between every two adjacent circular holes is 40mm.
Example 3:
in this example, the flow rate of the polyolefin elastomer solution entering the first-stage devolatilizer was 600kg/h, the solids content was 25wt%, and the temperature was 160 ℃. The first-stage preheater is heated by hot oil at 270 ℃, the temperature of the polyolefin elastomer solution at the outlet of the first-stage preheater is 240 ℃, the operating temperature of the first-stage devolatilizer is 200 ℃, and the operating pressure is 0.35MpaG.
The feeding distributor of the first-stage devolatilization device is provided with 310 holes, the long axis of the ellipse at the top of the elliptical table is 40mm, the short axis is 8mm, the center distance is 40mm, the long axis of the ellipse at the bottom is 5mm, the short axis is 1mm, and the cone angle at the bottom of the first-stage devolatilization device is 90 degrees.
The polyolefin elastomer solution at the inlet of the secondary devolatilizer had a solids content of 85 wt.% (i.e., a volatile content of 15 wt.%) and a feed temperature of 200 ℃. The secondary devolatilizer was heated with 4MpaG of steam at 260 ℃. The operating temperature of the secondary devolatilizer was 250 ℃ and the operating pressure was 0.1kpa, and the temperature of the outlet polyolefin elastomer melt reached 250 ℃ and the VOC content in the outlet melt was 1714ppm.
The feeding distributor of the secondary devolatilization device is provided with 310 holes, the long axis of the ellipse at the top of the elliptical table is 12mm, the short axis is 6mm, the center distance is 24mm, the long axis of the ellipse at the bottom is 3mm, the short axis is 1.5mm, and the cone angle at the bottom of the primary devolatilization device is 90 degrees.
The number of the circular holes formed in the steam feeding circular pipe is 20, the diameter of the circular holes is 12mm, and the center distance between every two adjacent circular holes is 96mm.
Comparative example 1:
in this example, the flow rate of the polyolefin elastomer solution entering the first-stage devolatilizer was 300kg/h, the solid content was 15wt%, and the temperature was 150 ℃. The primary preheater is heated by hot oil at 285 ℃, the temperature of the polyolefin elastomer solution at the outlet of the primary preheater is 270 ℃, the operating temperature of the primary devolatilizer is 224 ℃, and the operating pressure is 0.25MpaG.
220 holes are arranged on the feeding distributor of the first-stage devolatilization device,
the center distance of the round holes is 72mm.
The second devolatilizer inlet polyolefin elastomer solution had a solids content of 80 wt.% (i.e., a volatile content of 20 wt.%) and a feed temperature of 224 c. The second-stage devolatilizer was heated by introducing 3.5MpaG of steam at 245 ℃. The operating temperature of the secondary devolatilizer was 232 ℃ and the operating pressure was 0.5kpa, and the outlet polyolefin elastomer melt temperature reached 232 ℃ and the VOC content in the outlet melt was 9523ppm.
The feeding distributor of the secondary devolatilization device is provided with 150 holes, the long axis of the ellipse at the top of the elliptical table is 16mm, the short axis is 8mm, the center distance is 32mm, the long axis of the ellipse at the bottom is 4mm, the short axis is 1.6mm, and the apex angle of the cone at the bottom of the devolatilization device is 80 degrees.
The number of the circular holes formed in the steam feeding circular pipe is 34, the diameter of the circular holes is 8mm, and the center distance between every two adjacent circular holes is 40mm.
Comparative example 2:
in this example, the flow rate of the polyolefin elastomer solution entering the first-stage devolatilizer was 300kg/h, the solid content was 15wt%, and the temperature was 150 ℃. The primary preheater is heated by hot oil at 285 ℃, the temperature of the polyolefin elastomer solution at the outlet of the primary preheater is 270 ℃, the operating temperature of the primary devolatilizer is 240 ℃, and the operating pressure is 0.25MpaG.
220 openings are formed in a feeding distributor of the first-stage devolatilizer, the long axis of the top ellipse of the elliptical table is 24mm, the short axis of the top ellipse of the elliptical table is 7.2mm, the center distance is 72mm, the long axis of the bottom ellipse is 4mm, the short axis of the bottom ellipse is 1.6mm, and the apex angle of the bottom cone of the devolatilizer is 80 degrees.
The polyolefin elastomer solution at the inlet of the secondary devolatilizer had a solids content of 90 wt.% (i.e., a volatile content of 10 w.%) and a feed temperature of 240 ℃.
The feeding distributor of the secondary devolatilization device is provided with 150 holes,
the hole pitch is 32mm. The bottom of the secondary distributor is a common tube type heat exchanger, materials are fed in the heat exchange tube, 245 ℃ hot oil is fed out of the heat exchange tube, the outlet temperature of the heat exchanger is 243 ℃, the operating pressure in the devolatilization tank is 0.5kpa A, the temperature of the polyolefin elastomer melt at the outlet reaches 238 ℃, the VOC content in the melt reaches 1.5wt%, a large number of primary bubbles are contained in the melt, a large number of tiny secondary bubbles are contained on the inner wall of the primary bubbles, the discharge flow of a bottom melt discharge pump is obviously lower than the normal flow, and the liquid level control of a part of the melt pool at the conical section of the devolatilization tank is unstable. />
Claims (10)
1. An apparatus for polymer devolatilization, the apparatus comprising:
the pre-stage devolatilization device comprises a feeding distributor, a preheater and a devolatilization tank, wherein the feeding distributor is fixed at the top of the preheater, the devolatilization tank is positioned below the preheater and is connected through a flange, a melt feeding pump is positioned at the bottom of the devolatilization tank, and the feeding distributor is provided with an elliptical table-shaped hole;
the devolatilization device comprises a feeding distributor, a steam feeding pipe and a devolatilization tank, wherein the feeding distributor is fixed at the top of the devolatilization device, the feeding distributor is provided with an elliptical table-shaped hole, and the steam feeding pipe is arranged below the feeding distributor;
the preceding stage devolatilization device adopts one-stage or multi-stage series connection and then is connected with the final stage devolatilization device in series, and the preceding stage devolatilization device conveys materials to the top of the next stage devolatilization device through a pipeline by a melt pump.
2. The device according to claim 1, wherein the elliptical table-shaped holes are uniformly distributed on the feeding distributor in a regular triangle shape, the elliptical table has an upper ellipse and a lower ellipse which are concentric, the area of the upper ellipse is larger than that of the lower ellipse, and the height of the elliptical table is equal to the thickness of the feeding distributor;
preferably, the center-to-center distance between the upper base ellipses is 1-5 times of the major axis of the upper base ellipses.
3. The device according to claim 1 or 2, wherein the long axis of the ellipse of the upper base of the elliptical truncated cone-shaped hole is 2-8 times of the long axis of the ellipse of the lower base, the long axis of the ellipse of the upper base is 20-40mm, and the short axes of the ellipse of the upper base and the lower base are 0.2-0.5 times of the long axis.
4. The apparatus according to any one of claims 1 to 3, wherein the steam feed pipe of the last devolatilizer is provided with a circular ring pipe distributor, the outer diameter of the circular ring pipe distributor is equal to the diameter of the feed distributor of the last devolatilizer, circular holes are uniformly formed in the circular ring pipe, and the center distance between any two adjacent circular holes is equal.
5. A device according to claim 4, wherein the diameter of the circular holes is 6-12mm, and/or the center-to-center distance of the circular holes is 3-10 times, preferably 3-8 times, the diameter of the circular holes; preferably, the ring pipe distributor is 20-100mm below the feed distribution plate.
6. A method for devolatilizing polyolefin elastomers using the apparatus of any of claims 1 to 5 comprising the steps of:
s1: conveying the material at the outlet of the polyolefin elastomer reactor to a pre-stage devolatilization device for devolatilization;
s2, after the devolatilization in the step S1 is finished, conveying the mixture to a final-stage devolatilization device for devolatilization;
s3: and S2, discharging after devolatilization is finished.
7. The method according to claim 6, wherein the step S1 further comprises the steps of:
a1: the material enters a feeding distributor at the top of the pre-stage devolatilization device, is uniformly distributed through the distributor and enters a heat exchange tube of a preheater;
a2: polymer melt falling film evaporation is carried out in the heat exchange tube, and a heating medium is arranged outside the tube;
a3: the material flows out of the preheater and enters a devolatilization tank at the bottom, and is subjected to flash evaporation and devolatilization in the tank.
8. The method of claim 7, wherein the feed is a reactor outlet polyolefin elastomer solution having a volatile content of 75-92 wt%, and a feed temperature of 140-160 ℃;
preferably, the preheater is a single-tube-pass single-shell-pass tubular heat exchanger, hot oil is adopted as a shell-pass heating medium, the inlet temperature of the hot oil is 270-290 ℃, and the outlet temperature of tube-pass materials is 260-280 ℃;
preferably, the operating temperature of the pre-stage devolatilizer is 200-240 ℃, the operating temperature is 0.15-0.35MpaG, and the apex angle of the bottom cone of the devolatilizer is 75-90 degrees.
9. Method according to any of claims 6-7, wherein said step S2 further comprises the step of:
b1: materials at the outlet of the pre-stage devolatilization device are conveyed to the final-stage devolatilization device by a pump, and the materials enter the devolatilization tank in a falling strip shape after being uniformly distributed by the feeding distributor at the top;
b2: steam is uniformly dispersed into the gas phase space in the tank through the ring pipe distributor, and meanwhile, heating and steam stripping of the falling strips are realized.
10. The method according to claim 9, wherein the material is a polyolefin elastomer solution at the outlet of a pre-devolatilizer, wherein the volatile content is 5 to 15wt%, and the material temperature is 200 ℃ to 240 ℃;
preferably, the temperature of the steam is 240-260 ℃, and the pressure is 3-4MpaG;
preferably, the final-stage devolatilizer is provided with a pressure control loop, the steam air supplement and the vacuum pump air extraction rate are adjusted, the operation pressure is maintained to be 0.1-2kpA, and the apex angle of the bottom cone of the devolatilizer is 75-90 degrees.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005014667A1 (en) * | 2003-07-24 | 2005-02-17 | Bayer Technology Services Gmbh | Method and device for the elimination of volatile substances from high-viscous media |
| CN101422717A (en) * | 2008-11-21 | 2009-05-06 | 中国蓝星（集团）股份有限公司 | Gas liquid mixed feeding distributor and polyphenylene oxide reaction device using the same |
| CN104086349A (en) * | 2013-04-01 | 2014-10-08 | 中国石油化工股份有限公司 | Method for oligomerization production of alpha olefin from ethylene |
| CN108654124A (en) * | 2018-05-31 | 2018-10-16 | 万华化学集团股份有限公司 | The device and method of volatile organic compounds in a kind of removing lotion |
| CN208229449U (en) * | 2018-04-04 | 2018-12-14 | 星辉化学股份有限公司 | High viscosity fluid devolatilization staged cloth flow tube |
| CN112724296A (en) * | 2020-12-28 | 2021-04-30 | 江苏可立特工程设计研究有限公司 | Transparent polystyrene with capacity of more than 5 ten thousand tons and production equipment and process thereof |
-
2022
- 2022-10-28 CN CN202211331322.5A patent/CN115920428A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005014667A1 (en) * | 2003-07-24 | 2005-02-17 | Bayer Technology Services Gmbh | Method and device for the elimination of volatile substances from high-viscous media |
| CN101422717A (en) * | 2008-11-21 | 2009-05-06 | 中国蓝星（集团）股份有限公司 | Gas liquid mixed feeding distributor and polyphenylene oxide reaction device using the same |
| CN104086349A (en) * | 2013-04-01 | 2014-10-08 | 中国石油化工股份有限公司 | Method for oligomerization production of alpha olefin from ethylene |
| CN208229449U (en) * | 2018-04-04 | 2018-12-14 | 星辉化学股份有限公司 | High viscosity fluid devolatilization staged cloth flow tube |
| CN108654124A (en) * | 2018-05-31 | 2018-10-16 | 万华化学集团股份有限公司 | The device and method of volatile organic compounds in a kind of removing lotion |
| CN112724296A (en) * | 2020-12-28 | 2021-04-30 | 江苏可立特工程设计研究有限公司 | Transparent polystyrene with capacity of more than 5 ten thousand tons and production equipment and process thereof |
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