CN111333834B - Devolatilization method of nylon 6 melt - Google Patents
Devolatilization method of nylon 6 melt Download PDFInfo
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- CN111333834B CN111333834B CN202010147592.5A CN202010147592A CN111333834B CN 111333834 B CN111333834 B CN 111333834B CN 202010147592 A CN202010147592 A CN 202010147592A CN 111333834 B CN111333834 B CN 111333834B
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/46—Post-polymerisation treatment
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G69/00—Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
- C08G69/02—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids
- C08G69/08—Polyamides derived from amino-carboxylic acids or from polyamines and polycarboxylic acids derived from amino-carboxylic acids
- C08G69/14—Lactams
Abstract
The invention relates to the field of nylon materials, and discloses a devolatilization method of a nylon 6 melt, which comprises the following steps: 1) Introducing a nylon 6 melt and hot nitrogen containing water into a front-end devolatilization reaction kettle for devolatilization, and conveying the devolatilized nylon 6 melt to a rear-end devolatilization reaction kettle for secondary devolatilization; 2) The gaseous mixture enters a high boiling point component removal tower, and the high boiling point component in the gaseous mixture is discharged after being condensed; 3) The residual gaseous mixture enters a low boiling point component removing tower, and the low boiling point component is discharged after the gaseous mixture is sprayed, fractionated and condensed in the rising process; and residual gas is discharged after vacuum treatment. The invention can carry out high-efficiency devolatilization on the nylon 6 melt, can inhibit the polycondensation reaction of the nylon 6 in the devolatilization process, avoids the influence on the spinning forming process caused by the sudden expansion of the molecular weight of the nylon 6 under the vacuum condition, provides time for the nylon 6 amide exchange, narrows the molecular weight distribution and improves the melt quality.
Description
Technical Field
The invention relates to the field of nylon materials, in particular to a devolatilization method of a nylon 6 melt.
Background
The conversion of hydrolytic polymerization of caprolactam is typically around 90%, meaning that around 10% of caprolactam monomer and oligomer (also known as hot water extractables, where monomer is about 75% and oligomer is about 25%) remain in the polymer, and these impurities in the melt have a significant impact on spinning. Therefore, before the PA6 spinning, the chips need to be subjected to extraction treatment, and according to FZ/T51004-2011, the hot water extractables content of the PA6 chips is less than 0.5wt% (superior products). At present, the hot water continuous extraction technology is generally adopted in industry to extract monomers and oligomers in PA6 chips, so that the content of extractables in the chips is lower than 0.5wt%, and the requirement of high-speed spinning is met. However, a large amount of water and energy are consumed in the processes of extraction, drying and remelting, and according to statistics, in the production process of the PA6 slices, the energy consumption in the processes of extraction and drying accounts for 15-20% of that in the production process of the PA6 slices, so that the production cost of the PA6 fibers is greatly improved. In order to avoid the defects, the PA6 spinning technology is pushed to the direction of direct spinning in the future, and compared with the spinning by a slicing method, the melt direct spinning technology can greatly simplify the production flow, has low capital construction investment per unit yield and is beneficial to further reducing the fiber production cost.
The main method for reducing the hot water extractable content in the caprolactam hydrolysis polymerization process is to control the polymerization temperature, because the caprolactam polymerization is a balance relation which changes along with the temperature change, and the hot water extractable content is more favorably generated along with the temperature rise, especially cyclic oligomer, so that the hot water extractable content can be effectively controlled by controlling the polymerization temperature, namely low-temperature polymerization. In order to ensure that the polymerization process is carried out in a liquid state, the polymerization temperature is required to be at least 10 ℃ below the melting point of nylon 6, the polymerization temperature can not control the hot water extractables in the range of direct spinning by a fusible body, and the low-temperature polymerization has another defect that the reaction speed is slow, and the molecular weight of the obtained polymer is low; spinning fibres from low temperature polymers requires first raising the polymer to the processing temperature, however, since the reaction has a chemical equilibrium and the formation of low molecular weight compounds is less advantageous than in normal polymerization processes, it is necessary to reduce the hot water extractables content of the melt by means of further processes.
The applicant found that in the previous studies, under certain devolatilization conditions, the monomer in the nylon 6 melt can be effectively removed, and in the process, the removal of the monomer can also drive other oligomers, especially cyclic dimer, to sublimate and be removed from the melt, thereby providing a way for reducing the content of hot water extractables in the nylon 6 melt. However, to achieve a large amount of hot water extractables removal requires a high devolatilization area and vacuum in the apparatus, and the molecular weight of nylon 6 rapidly increases and the melt viscosity increases greatly, resulting in molding difficulties. In addition, how to collect the volatile, avoid the pipeline to appear blockking up to effective retrieval and utilization volatile is influencing PA6 production efficiency equally. Therefore, the aim of reducing the content of hot water extractables in the nylon 6 melt and efficiently recycling the hot water extractables is fulfilled by developing a devolatilization process special for nylon 6, and the development trend of the nylon 6 industry is reached.
Disclosure of Invention
In order to solve the technical problems, the invention provides a devolatilization method of a nylon 6 melt, which adopts a multi-stage devolatilization process and can improve the devolatilization efficiency. Meanwhile, the method can avoid the influence of the sudden expansion of the molecular weight of the nylon 6 on the spinning forming process under the vacuum condition, and also provides time for nylon 6 amide exchange, so that the molecular weight distribution is narrowed, and the melt quality is improved.
The specific technical scheme of the invention is as follows: a devolatilization method of nylon 6 melt comprises the following steps:
1) And respectively introducing the nylon 6 melt and water-containing hot nitrogen into a devolatilization reaction kettle at the front end through respective channels for devolatilization, removing most of hot water extractables in the nylon 6 melt, mixing the hot water extractables with the hot nitrogen to form a gaseous mixture, discharging the gaseous mixture from the devolatilization reaction kettle, conveying the devolatilized nylon 6 melt to the devolatilization reaction kettle at the rear end for secondary devolatilization without introducing nitrogen, and discharging the nylon 6 melt and the gaseous mixture generated after the secondary devolatilization from the devolatilization reaction kettle respectively.
2) And the gaseous mixture is converged and then enters a high boiling point component removing tower, and the high boiling point component in the gaseous mixture is condensed and then discharged from the bottom of the tower and collected.
3) The residual gaseous mixture enters a low boiling point component removing tower, and the low boiling point component in the gaseous mixture falls into the tower bottom to be discharged and collected after the gaseous mixture is sprayed, fractionated and condensed in the rising process; and residual gas is discharged after vacuum treatment.
The devolatilization method of the invention has the working principle that:
the method comprises the following steps of devolatilizing a nylon 6 melt through a devolatilization system, blowing hot nitrogen containing trace moisture out of a devolatilization disc through air holes in a devolatilization reaction kettle at the front end, so that the nylon 6 melt attached to the devolatilization disc is bubbled to form a thinner melt film, the devolatilization area can be further increased, and the devolatilization efficiency is improved. When the melt bubbles grow to a certain extent, they break and the gas is carried away from the system under the action of vacuum. In addition, as the cyclic dimer and other nonvolatile components have better solubility in hot water, the moisture in the hot nitrogen gas flow can interact with the cyclic dimer and other nonvolatile components, the cyclic dimer and other nonvolatile components can be driven to volatilize, the content of the nonvolatile components in the melt is reduced, the content of oligomers in the melt is further reduced, and the quality of the melt is improved. Finally, the gas containing the devolatilization component is discharged, and the devolatilized nylon 6 melt flows out from a melt outlet, the hot water extractables content of the obtained nylon 6 melt is less than or equal to 1.5wt%, the cyclic dimer content is less than or equal to 0.3 wt%, and the nylon 6 melt can be directly spun or directly made into plastic products.
To the best of the applicant's knowledge, the prior art is directed to the hot water extraction devolatilization of nylon 6 melt, and there is no nylon 6 devolatilization method similar to the above working principle of the present invention. As described in the background of the present application, in the conventional devolatilization process, a device with a high devolatilization area and a high vacuum degree are required, and under the high devolatilization, the molecular weight of nylon 6 can be rapidly increased, and the melt viscosity is greatly increased, so that the molding is difficult. The devolatilization method of the invention has the advantages that: because the system contains a certain amount of water, the polycondensation reaction of the nylon 6 is inhibited, the phenomenon that the molecular weight of the nylon 6 swells under the vacuum condition to influence the spinning forming process is avoided, time is provided for the amide exchange of the nylon 6, the molecular weight distribution is narrowed, and the melt quality is improved. In addition, as the cyclic dimer and other nonvolatile components have better solubility in hot water, the moisture in the hot nitrogen gas flow can interact with the cyclic dimer and other nonvolatile components, the cyclic dimer and other nonvolatile components can be driven to volatilize, the content of the nonvolatile components in the melt is reduced, the content of oligomers in the melt is further reduced, and the quality of the melt is improved.
It should be noted that, for a plurality of devolatilization reaction kettles connected in series, only the devolatilization reaction kettle positioned at the foremost end is filled with nitrogen containing moisture, and for the devolatilization reaction kettle at the rear end, which is not filled with gas, only vacuum pumping is performed, and the action is performed for a relatively short time, so as to further remove volatiles, and simultaneously remove moisture in the system, so as to meet the spinning requirement.
After devolatilization: hot water extractables removed from the melt are mixed with gas and then sequentially treated by a high boiling point component removing unit and a low boiling point component removing unit in a gaseous state, the hot water extractables are condensed and collected in the system, and finally, products are conveyed to a polymerization system again to participate in polymerization reaction.
Preferably, in the step 1), the absolute pressure in the devolatilization reaction kettle positioned at the front end is 500-5000Pa, the temperature is 240-270 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 0.5-3h; the absolute pressure in the devolatilization reaction kettle at the rear end is below 500Pa, the temperature is 240-270 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 10-30min.
In the devolatilization step, a front devolatilization reaction kettle and a rear devolatilization reaction kettle are designed, and the process parameters are designed to be different in a targeted manner: the front devolatilization reaction kettle has a good devolatilization effect, most of volatiles can be removed, and because the existence of water molecules inhibits the progress of polymerization reaction, the long-time polymerization can be carried out to reduce the volatile content, and meanwhile, the time is prolonged, time is provided for the amide exchange reaction between nylon 6 molecular chains, and the amide exchange reaction is sufficient, so that the molecular weight distribution can be narrowed. The post-devolatilization is mainly devolatilization under high vacuum condition, which removes water and the part difficult to devolatilize in the system, and because no water is supplemented, the long devolatilization time can cause the molecular weight to be greatly increased, which is not beneficial to the subsequent processing, so the low retention time is adopted. (the reason why only the post-devolatilization is not used is that the molecular weight is rapidly increased without moisture replenishment, resulting in non-uniformity of the molecular weight distribution; the polymerization time for achieving the target molecular weight is short, and there is no time for the amide exchange between the molecular chains, resulting in broadening of the molecular weight distribution).
Preferably, in step 1), the hot nitrogen gas has a water content of 0.1 to 10wt%.
The water content control is controlled in accordance with the polymerization target molecular weight and the devolatilization amount, and too low a water content makes it impossible to suppress the polymerization reaction, and too high a water content makes it impossible to perform the polymerization reaction because the devolatilization effect is lowered.
Preferably, in step 1), the temperature of the nylon 6 melt is maintained at 240-270 ℃ during the transportation between different devolatilization reactors and to the high boiling point component removal column.
The conveying process needs to be insulated to prevent the materials from being adhered in the pipeline.
Preferably, in the step 2), the working temperature of the high boiling point component removing tower is 100-200 ℃, and the rotating speed of the helical blade in the high boiling point component removing tower is 10-400r/min.
Preferably, in step 2), the temperature of the gaseous mixture is maintained at 80 to 120 ℃ during the transfer from the high-boiling component removal column to the low-boiling component removal column.
Preferably, in the step 3), the operating temperature of the low boiling point component removal column is 60 to 80 ℃.
Preferably, in the step 3), the spraying medium is water or caprolactam, and the spraying temperature is 60-80 ℃;
the fractionation is hot water fractionation at 70-80 ℃; the temperature of the condensation is 0-30 ℃.
A multistage devolatization device for nylon 6 melt comprises a devolatization system and a component collection system which are sequentially connected.
Wherein the devolatilization system comprises a plurality of devolatilization reaction kettles which are connected in series and/or in parallel; the devolatilization reaction kettle comprises a shell, a hollow rotating shaft, a motor and at least one devolatilization disc; the bottom of the shell is provided with a melt inlet and a melt outlet, the middle part of the side surface of the shell is provided with a gas inlet, and the top of the shell is provided with a gas outlet; the hollow rotating shaft is horizontally arranged in the shell, one end of the hollow rotating shaft is communicated with the gas inlet, and the motor is used for driving the hollow rotating shaft to rotate; the devolatilization discs are fixed on the hollow rotating shaft through hollow branch pipes communicated with the hollow rotating shaft, and when the number of the devolatilization discs is multiple, the multiple devolatilization discs are sequentially arranged on the hollow rotating shaft in parallel; the devolatilization disc is distributed with air holes; the gas outlet of the devolatilization reaction kettle is connected with a component collecting system.
The component collecting system comprises a high boiling point component removing unit and a low boiling point component removing unit which are connected in sequence.
The working principle of the multistage devolatilization device is as follows:
a devolatilization system: at first devolatilizing nylon 6 melt through a devolatilizing system, allowing the nylon 6 melt to enter a devolatilizing reaction kettle through a melt inlet, introducing wet nitrogen through a gas inlet, driving a devolatilizing disc to rotate by a hollow rotating shaft (the rotating devolatilizing disc can take up the nylon 6 melt positioned at the bottom of the devolatilizing disc (the melt is attached to the surface of the devolatilizing disc to form a layer of film), heating the devolatilizing reaction kettle by an external heating device, vacuumizing the devolatilizing reaction kettle by an external vacuum device, adhering the nylon 6 melt to the surface of the devolatilizing disc under the conditions, wherein the flow route of the wet nitrogen is as follows: in addition, because the hard volatile components such as the annular dimer and the like have better solubility in hot water, the water in the hot nitrogen gas flow can interact with the hard volatile components such as the annular dimer and the like, the hard volatile components such as the annular dimer and the like can be driven to volatilize, the content of the hard volatile components in the melt can be reduced, the content of oligomers in the melt is further reduced, the melt quality is improved, finally, the gas containing the devolatilization components is discharged from a volatile gas outlet, the devolatilized nylon 6 melt flows out from a melt outlet, the content of the hot water extractables of the nylon 6 melt is less than or equal to 1.5wt%, the content of the annular dimer is less than or equal to 0.3wt, and the nylon 6 can be directly spun or directly made into a plastic product.
Component collection system: and hot water extractables removed from the melt are mixed with gas, then are introduced into the component collecting system in a gaseous state, and are sequentially treated by the high-boiling-point component removing unit and the low-boiling-point component removing unit, the hot water extractables are condensed and collected in the system, and final products are conveyed to the polymerization system again to participate in polymerization reaction.
Preferably, the diameter of the air hole of the devolatilization reaction kettle is 0.1-10mm.
The diameter of the air hole is limited within the range of 0.1-10mm, the air hole can be adjusted according to the viscosity of the melt in actual production, attention needs to be paid to avoid the melt from flowing into the air hole when the diameter is designed, and meanwhile, the resistance of the melt flowing on the disc is reduced.
Preferably, the devolatilization reaction kettles connected in series and/or in parallel are connected through a melt inlet and a melt outlet, and the gas outlets are converged through a pipeline.
Preferably, the high boiling point component removal unit comprises one or more high boiling point component removal columns connected in parallel; the top of each high boiling point component removing tower is respectively provided with an air inlet and an air outlet; a vertical exhaust pipe and a rotatable helical blade (driven by a rotating motor at the top of the tower) which vertically surrounds the outer side of the exhaust pipe and is attached to the inner wall of the high boiling point component removing tower are arranged in the high boiling point component removing tower; the top of the exhaust pipe is communicated with the air outlet, and the bottom of the exhaust pipe is provided with an opening; the bottom of each high boiling point component removal column is connected with a fine powder receiving tank.
The working principle of the high boiling point component removing tower is as follows: after the gas flow in the devolatilization system is introduced into the high boiling point component removal tower, the gas flow is changed from linear motion to circular motion, when the gas flow contacts with the helical blade and the inner wall with lower temperature, the high boiling point component can be condensed on the helical blade and the inner wall, and the high boiling point component (mainly oligomer) condensed on the helical blade is thrown away under the action of centrifugal force and then falls into the fine powder receiving tank under the action of gravity; while the high boiling point component condensed on the inner wall is scraped off from the inner wall by the rotating helical blade and also falls down into the fine powder receiving tank by gravity. The low boiling point component enters the low boiling point component removal unit through an opening at the bottom of the vent pipe along with the gas.
Preferably, the gas inlet of the high boiling point component removal column has a gas inlet direction horizontally tangential to the inner wall of the high boiling point component removal column.
After the airflow is tangentially introduced from the inner wall of the high boiling point component removing tower, the airflow can be ensured to move along the peripheral side of the inner wall in the high boiling point component removing tower, on one hand, a vortex can be formed, the moving path of the airflow is prolonged, and the heat exchange time is prolonged; on the other hand, the high boiling point component adhering to the inner wall can be effectively "swept" and dropped.
Preferably, a heating device is installed on an outer wall of the high boiling point component removal column.
Preferably, the bottom of the high boiling point component removal column has a conical shape with a large top and a small bottom.
The design of the shape is beneficial to falling and collecting the fine powder.
Preferably, the low boiling point component removal unit comprises one or more of a low boiling point component removal column, a recovery tank, a spray column, a fractionation column, a condensing column and a vacuum device connected in parallel; each low boiling point component removing tower is internally provided with a rotatable scraper attached to the inner wall of the low boiling point component removing tower, and the recovery tank is connected with the bottom of the low boiling point component removing tower; the spray tower is arranged at the top of the low-boiling-point component removing tower, and a fractionating tower, a condensing tower and a vacuum device are sequentially connected behind the spray tower.
The low boiling point component removing tower is of a horizontal structure, and the working principle is as follows: the scraper is arranged in the low boiling point component removing tower and can periodically rotate along the inner wall, so that the low boiling point component (the main component is caprolactam) is prevented from being accumulated on the inner wall and being accumulated into hard matters after a long time, and the heat transfer and the working efficiency of the system are influenced. The gas moves upwards after entering the low boiling point component removing tower and needs to pass through a spray tower, the spray medium of the spray tower can be water or caprolactam, and the spray temperature is 60-80 ℃; the low boiling point component in the gas is separated from the gas after being cooled, and the liquid after being sprayed and cooled is collected in a recovery tank and can be conveyed to a polymerization system under the action of a conveying pump for direct recycling. While the gas fraction continues to be processed through a fractionation column and a condensation column in that order. Wherein the fractionating tower is condensed with hot water at a temperature of 70-80 deg.C in order to condense caprolactam remaining in the gas stream, the gas is then passed through a condensing tower at a temperature of 0-30 deg.C in order to condense water from the gas stream, and finally passed through a vacuum device.
Preferably, the vacuum device comprises one or a combination of a plurality of stages of a rotary vane vacuum pump, a molecular vacuum pump, an ejector vacuum pump, a diffusion pump and a diffusion ejector pump.
Preferably, the inner wall of the high boiling point component removal column, the helical blade, the inner wall of the low boiling point component removal column, and the scraper are subjected to a non-stick treatment.
The parts can avoid the adhesion and accumulation of sticky materials on the surfaces of the parts after non-stick treatment.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention provides a multistage devolatilization method capable of removing hot water extractables in nylon 6 melt, which has the advantages of short flow, high speed, low energy consumption and the like compared with the conventional hot water extraction process, and through the device, the direct spinning of the nylon 6 melt can be realized, the production cost of the nylon 6 is greatly reduced, the single-line capacity is greatly improved, the flow is short, and the capital investment of unit capacity is greatly reduced.
(2) In the devolatilization system, the invention adopts a multi-stage devolatilization design, in each devolatilization reaction kettle, the introduced gas can bubble the melt attached to the devolatilization disc to form a thinner melt film, thereby further increasing the devolatilization area and improving the devolatilization efficiency, when the melt bubbles are increased to a certain degree, the melt bubbles can be broken, the gas can be brought into a separation system under the vacuum action, further improving the diffusion area and greatly improving the devolatilization effect. Meanwhile, because the system contains a certain amount of water, the polycondensation reaction of the nylon 6 is inhibited, the phenomenon that the molecular weight of the nylon 6 swells under the vacuum condition to influence the spinning forming process is avoided, time is provided for nylon 6 amide exchange, the molecular weight distribution is narrowed, and the melt quality is improved. In addition, as the cyclic dimer and other nonvolatile components have better solubility in hot water, the moisture in the hot nitrogen gas flow can interact with the cyclic dimer and other nonvolatile components, the cyclic dimer and other nonvolatile components can be driven to volatilize, and the content of the nonvolatile components in the melt is reduced, so that the content of oligomers in the melt is further reduced, and the quality of the melt is improved.
(3) The mixed gas generated by the devolatilization system adopts a multi-stage separation mode to collect hot water extractables in the gas, high-boiling-point components are collected by a method of providing high contact area condensation, and meanwhile, the spiral blades can avoid the accumulation of the components on the inner wall; the low boiling point components are collected by a spray condensing mode, a scraper is arranged to avoid the accumulation of the components in the equipment, and a fractionating tower and a condensing tower are arranged to further purify the air flow so as to avoid the influence of the volatile components entering a vacuum pump on the working efficiency and the service life of the vacuum pump; these designs greatly increase the life cycle of the condensing system and increase the stability of the system.
(4) The invention can separate high boiling point component and low boiling point component through multi-stage separation, the high boiling point component can be sent to the cracking kettle for recycling after treatment, and the low boiling point component can be directly recycled.
Drawings
Fig. 1 is a schematic structural view of a devolatilization plate in examples 1 and 2 of the present invention.
FIG. 2 is a schematic structural view of embodiment 1 of the present invention;
FIG. 3 is a schematic structural view of embodiment 2 of the present invention;
the reference signs are: a devolatilization reaction kettle 1, a high boiling point component removing tower 2, a fine powder receiving tank 3, a low boiling point component removing tower 4, a spray tower 5, a fractionating tower 6, a condensing tower 7, a vacuum device 8, a recovery tank 9, a shell 101, a hollow rotating shaft 102, a motor 103, a devolatilization disc 104, a melt inlet 105, a melt outlet 106, a gas inlet 107, a gas outlet 108, a hollow branch pipe 109, an air hole 110, a gas inlet 201, a gas outlet 202, a gas exhaust pipe 203, a helical blade 204 and a scraper 401.
Detailed Description
The present invention will be further described with reference to the following examples.
General examples
A devolatilization method of nylon 6 melt comprises the following steps:
1) And respectively introducing the nylon 6 melt and hot nitrogen containing water into a devolatilization reaction kettle at the front end through respective channels for devolatilization, removing most of hot water extractables in the nylon 6 melt, mixing the hot water extractables with the hot nitrogen to form a gaseous mixture, discharging the gaseous mixture from the devolatilization reaction kettle, conveying the devolatilized nylon 6 melt to the devolatilization reaction kettle at the rear end for secondary devolatilization without introducing nitrogen, and discharging the nylon 6 melt and the gaseous mixture generated after the secondary devolatilization from the devolatilization reaction kettle respectively.
2) And the gaseous mixture enters a high boiling point component removal tower after confluence, and the high boiling point component in the gaseous mixture is discharged from the bottom of the tower after being condensed and collected.
3) The residual gaseous mixture enters a low boiling point component removing tower, and the low boiling point component in the gaseous mixture falls into the tower bottom to be discharged and collected after the gaseous mixture is sprayed, fractionated and condensed in the rising process; and residual gas is discharged after vacuum treatment.
Preferably, in the step 1), the absolute pressure in the devolatilization reaction kettle positioned at the front end is 500-5000Pa, the temperature is 240-270 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 0.5-3h; the absolute pressure in the devolatilization reaction kettle positioned at the rear end is below 500Pa, the temperature is 240-270 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 10-30min.
Preferably, in step 1), the hot nitrogen gas has a water content of 0.1 to 10wt%.
Preferably, in step 1), the temperature of the nylon 6 melt is maintained at 240-270 ℃ during the transportation between different devolatilization reaction kettles and to the high boiling point component removal tower.
Preferably, in the step 2), the working temperature of the high boiling point component removing tower is 100-200 ℃, and the rotating speed of the spiral blade in the high boiling point component removing tower is 10-400r/min.
Preferably, in step 2), the temperature of the gaseous mixture is maintained at 80 to 120 ℃ during the transfer from the high boiling component removal column to the low boiling component removal column.
Preferably, the operating temperature of the low boiling point component removal column in step 3) is 60 to 80 ℃.
Preferably, in the step 3), the spraying medium is water or caprolactam, and the spraying temperature is 60-80 ℃;
the fractionation is hot water fractionation at 70-80 ℃; the temperature of the condensation is 0-30 ℃.
A multistage devolatilization device for nylon 6 melt comprises a devolatilization system and a component collection system which are sequentially connected.
Wherein, the devolatilization system comprises a plurality of devolatilization reaction kettles 1 which are connected in series and/or in parallel; the devolatilization reaction kettle comprises a shell 101, a hollow rotating shaft 102, a motor 103 and at least one devolatilization disk 104; the bottom of the shell is provided with a melt inlet 105 and a melt outlet 106, the middle part of the side surface of the shell is provided with a gas inlet 107, and the top of the shell is provided with a gas outlet 108 (the melt inlet and the melt outlet, the gas inlet and the gas outlet are positioned on opposite sides); the hollow rotating shaft is horizontally arranged in the shell, one end of the hollow rotating shaft is communicated with the gas inlet, and the motor is used for driving the hollow rotating shaft to rotate; the devolatilization discs are fixed on the hollow rotating shaft through hollow branch pipes 109 communicated with the hollow rotating shaft, and when the number of the devolatilization discs is multiple, a plurality of the devolatilization discs are sequentially arranged in parallel on the hollow rotating shaft; the devolatilization disc is distributed with air holes 110; the gas outlet of the devolatilization reaction kettle is connected with a component collecting system.
The component collecting system comprises a high boiling point component removing unit and a low boiling point component removing unit which are connected in sequence.
Preferably, the diameter of the air hole of the devolatilization reaction kettle is 0.1-10mm.
Preferably, the devolatilization reaction kettles connected in series and/or in parallel are connected through a melt inlet and a melt outlet, and the gas outlets are converged through a pipeline.
Preferably, the high boiling point component removal unit includes one or more high boiling point component removal columns 2 connected in parallel; the top of each high boiling point component removing tower is respectively provided with an air inlet 201 and an air outlet 202; a vertical exhaust pipe 203 and a rotatable helical blade 204 which vertically surrounds the outer side of the exhaust pipe and is attached to the inner wall of the high boiling point component removal tower are arranged in the high boiling point component removal tower; the top of the exhaust pipe is communicated with the air outlet, and the bottom of the exhaust pipe is provided with an opening; the bottom of each high boiling point component removal column is connected to a fine powder receiving tank 3.
Preferably, the gas inlet of the high boiling point component removal column has a gas inlet direction horizontally tangential to the inner wall of the high boiling point component removal column.
Preferably, a heating device is installed on an outer wall of the high boiling point component removal column.
Preferably, the bottom of the high boiling point component removal column has a conical shape with a large top and a small bottom.
Preferably, the low boiling point component removal unit includes one or more of a low boiling point component removal column 4, a recovery tank 9, a spray column 5, a fractionation column 6, a condensation column 7 and a vacuum apparatus 8 connected in parallel. A rotatable scraper 401 attached to the inner wall of the low boiling point component removal tower is arranged in each low boiling point component removal tower, and the recovery tank is connected with the bottom of the low boiling point component removal tower; the spray tower is arranged at the top of the low-boiling-point component removal tower, and a fractionating tower, a condensing tower and a vacuum device are sequentially connected behind the spray tower.
Preferably, the vacuum device comprises one or a combination of a plurality of stages of a rotary vane vacuum pump, a molecular vacuum pump, an ejector vacuum pump, a diffusion pump and a diffusion ejector pump.
Preferably, the inner wall of the high boiling point component removal column, the helical blade, the inner wall of the low boiling point component removal column, and the scraper are subjected to non-stick treatment.
Example 1
A devolatilization method of nylon 6 melt comprises the following steps:
1) Respectively introducing a nylon 6 melt and hot nitrogen with the water content of 0.1wt% into a devolatilization reaction kettle at the front end through respective channels for devolatilization, removing most of hot water extractables in the nylon 6 melt, mixing the hot water extractables with the hot nitrogen to form a gaseous mixture, discharging the gaseous mixture from the devolatilization reaction kettle, conveying the devolatilized nylon 6 melt to a devolatilization reaction kettle at the rear end for secondary devolatilization without introducing nitrogen, and discharging the nylon 6 melt and the gaseous mixture generated after the secondary devolatilization from the devolatilization reaction kettle respectively. Wherein the absolute pressure in the devolatilization reaction kettle positioned at the front end is 500Pa, the temperature is 240 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 0.5h; the absolute pressure in the devolatilization reaction kettle positioned at the rear end is below 500Pa, the temperature is 270 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 10min. The temperature of the nylon 6 melt was maintained at 270 ℃ during the transfer between the different devolatilization reactors and to the high-boiling component removal column.
2) And the gaseous mixture enters a high boiling point component removal tower after confluence, and the high boiling point component in the gaseous mixture is discharged from the bottom of the tower after being condensed and collected. The working temperature of the high boiling point component removing tower is 200 ℃, and the rotating speed of the helical blade in the high boiling point component removing tower is 10r/min. The temperature of the gaseous mixture was maintained at 80 ℃ during the transfer from the high boiling component removal column to the low boiling component removal column.
3) The residual gaseous mixture enters a low boiling point component removal tower, and the low boiling point component in the gaseous mixture falls into the tower bottom to be discharged and collected after the gaseous mixture is sprayed, fractionated and condensed in the rising process; and residual gas is discharged after vacuum treatment. The operating temperature of the low boiling point component removal column was 80 ℃. The spraying medium is water, and the spraying temperature is 80 ℃; the fractionation is a hot water fractionation at 70 ℃; the temperature of the condensation was 30 ℃.
A multistage devolatilization device for nylon 6 melt comprises a devolatilization system and a component collection system which are sequentially connected.
As shown in fig. 2, the devolatilization system comprises a front devolatilization reaction kettle 1 and a rear devolatilization reaction kettle 1 which are connected in series; the devolatilization reaction kettle comprises a shell 101, a hollow rotating shaft 102, a motor 103 and eleven devolatilization discs 104; the bottom of the shell is provided with a melt inlet 105 and a melt outlet 106, the middle of the side surface of the shell is provided with a gas inlet 107, and the top of the shell is provided with a gas outlet 108 (the melt inlet and the melt outlet, the gas inlet and the gas outlet are positioned on opposite sides); the hollow rotating shaft is horizontally arranged in the shell, one end of the hollow rotating shaft is communicated with the gas inlet, and the motor is used for driving the hollow rotating shaft to rotate; as shown in fig. 1, the devolatilization discs are fixed on the hollow rotating shaft through hollow branch pipes 109 communicated with the hollow rotating shaft, eleven devolatilization discs are sequentially connected in series and arranged in parallel on the hollow rotating shaft; the devolatilization disc is distributed with air holes 110 (the diameter is 10 mm); the gas outlet of the devolatilization reaction kettle is connected with a component collecting system. The devolatilization reaction kettles connected in series are connected through a melt inlet and a melt outlet, and all gas outlets converge through a pipeline.
The component collecting system comprises a high boiling point component removing unit and a low boiling point component removing unit which are connected in sequence.
Wherein the high boiling point component removal unit comprises two high boiling point component removal columns 2 connected in parallel; the top of each high boiling point component removing tower is respectively provided with an air inlet 201 (the air inlet direction is horizontally tangent to the inner wall of the high boiling point component removing tower) and an air outlet 202; a vertical exhaust pipe 203 and a rotatable helical blade 204 (driven by a rotating motor) which vertically surrounds the outer side of the exhaust pipe and is attached to the inner wall of the high boiling point component removal tower are arranged in the high boiling point component removal tower; the top of the exhaust pipe is communicated with the air outlet, and the bottom of the exhaust pipe is provided with an opening; the bottom of each high boiling point component removal column is connected to a fine powder receiving tank 3. The outer wall of the high boiling point component removing tower is provided with a heating device, and the bottom of the high boiling point component removing tower is in a conical shape with a big top and a small bottom.
The low boiling point component removing unit comprises a low boiling point component removing tower 4, a recovery tank 9, a spray tower 5, a fractionating tower 6, a condensing tower 7 and a vacuum device 8. A rotatable scraper 401 (driven by a rotating motor) attached to the inner wall of the low-boiling-point component removal tower is arranged in the low-boiling-point component removal tower, and the recovery tank is connected with the bottom of the low-boiling-point component removal tower; the spray tower is arranged at the top of the low boiling point component removing tower, and a fractionating tower, a condensing tower and a vacuum device (a rotary vane vacuum pump) are sequentially connected behind the spray tower.
Wherein the inner wall of the high boiling point component removing tower, the helical blade, the inner wall of the low boiling point component removing tower, the scraper and the inner wall of the connected pipeline are subjected to non-stick treatment.
In the step (1), the molecular weight of the nylon 6 melt generated after the secondary devolatilization is 16600, and the molecular weight distribution is 1.35.
Example 2
A devolatilization method of nylon 6 melt comprises the following steps:
1) Respectively introducing a nylon 6 melt and hot nitrogen with the water content of 10wt% into devolatilization reaction kettles (two parallel) at the front end through respective channels for devolatilization, removing most of hot water extractables in the nylon 6 melt, mixing the hot water extractables with the hot nitrogen to form a gaseous mixture and discharging the gaseous mixture from the devolatilization reaction kettles, conveying the devolatilized nylon 6 melt to the devolatilization reaction kettle at the rear end (positioned at the rear end in series) for secondary devolatilization without introducing nitrogen, and discharging the nylon 6 melt and the gaseous mixture generated after the secondary devolatilization from the devolatilization reaction kettles respectively. Wherein the absolute pressure in the devolatilization reaction kettle positioned at the front end is 1000Pa, the temperature is 250 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 2h; the absolute pressure in the devolatilization reaction kettle positioned at the rear end is below 500Pa, the temperature is 255 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 10min. The temperature of the nylon 6 melt is kept at 250 ℃ during the conveying among different devolatilization reaction kettles and the conveying to the high boiling point component removing tower.
2) And the gaseous mixture is converged and then enters a high boiling point component removing tower, and the high boiling point component in the gaseous mixture is condensed and then discharged from the bottom of the tower and collected. The working temperature of the high boiling point component removing tower is 150 ℃, and the rotating speed of the helical blade in the high boiling point component removing tower is 100r/min. The temperature of the gaseous mixture was maintained at 100 ℃ during the transfer from the high boiling component removal column to the low boiling component removal column.
3) The residual gaseous mixture enters a low boiling point component removing tower, and the low boiling point component in the gaseous mixture falls into the tower bottom to be discharged and collected after the gaseous mixture is sprayed, fractionated and condensed in the rising process; and residual gas is discharged after vacuum treatment. The operating temperature of the low boiling point component removal column was 60 ℃. The spraying medium is caprolactam, and the spraying temperature is 60 ℃; the fractionation is hot water fractionation at 80 ℃; the temperature of the condensation was 0 ℃.
A multistage devolatization device for nylon 6 melt comprises a devolatization system and a component collection system which are sequentially connected.
As shown in fig. 3, the devolatilization system comprises a front devolatilization reaction kettle 1 and a back devolatilization reaction kettle 1 which are connected in parallel, and a devolatilization reaction kettle which is connected in series with the two devolatilization reaction kettles which are connected in parallel; each devolatilization reaction kettle comprises a shell 101, a hollow rotating shaft 102, a motor 103 and eleven devolatilization discs 104; the bottom of the shell is provided with a melt inlet 105 and a melt outlet 106, the middle of the side surface of the shell is provided with a gas inlet 107, and the top of the shell is provided with a gas outlet 108 (the melt inlet and the melt outlet, the gas inlet and the gas outlet are positioned on opposite sides); the hollow rotating shaft is horizontally arranged in the shell, one end of the hollow rotating shaft is communicated with the gas inlet, and the motor is used for driving the hollow rotating shaft to rotate; as shown in fig. 1, the devolatilization discs are fixed on the hollow rotating shaft through hollow branch pipes 109 communicated with the hollow rotating shaft, eleven devolatilization discs are sequentially connected in series and arranged in parallel on the hollow rotating shaft; the devolatilization disc is distributed with air holes 110 (the diameter is 0.1 mm); the gas outlet of the devolatilization reaction kettle is connected with a component collecting system. The devolatilization reaction kettles connected in series are connected through a melt inlet and a melt outlet, and all gas outlets converge through a pipeline.
The component collecting system comprises a high boiling point component removing unit and a low boiling point component removing unit which are connected in sequence.
Wherein the high boiling point component removal unit comprises two parallel high boiling point component removal columns 2; the top of each high boiling point component removing tower is respectively provided with an air inlet 201 (the air inlet direction is horizontally tangent to the inner wall of the high boiling point component removing tower) and an air outlet 202; a vertical exhaust pipe 203 and a rotatable helical blade 204 (driven by a rotating motor) which vertically surrounds the outer side of the exhaust pipe and is attached to the inner wall of the high boiling point component removal tower are arranged in the high boiling point component removal tower; the top of the exhaust pipe is communicated with the air outlet, and the bottom of the exhaust pipe is provided with an opening; the bottom of each high boiling point component removal column is connected to a fine powder receiving tank 3. The outer wall of the high boiling point component removing tower is provided with a heating device, and the bottom of the high boiling point component removing tower is in a conical shape with a big top and a small bottom.
The low boiling point component removal unit comprises a low boiling point component removal tower 4, a recovery tank 9, a spray tower 5, a fractionating tower 6, a condensing tower 7 and a vacuum device 8. A rotatable scraper 401 (driven by a rotating motor) attached to the inner wall of the low-boiling-point component removal tower is arranged in the low-boiling-point component removal tower, and the recovery tank is connected with the bottom of the low-boiling-point component removal tower; the spray tower is arranged at the top of the low boiling point component removal tower, and a fractionating tower, a condensing tower and a vacuum device (a molecular vacuum pump) are sequentially connected behind the spray tower.
Wherein, the inner wall of the high boiling point component removing tower, the helical blade, the inner wall of the low boiling point component removing tower, the scraper and the inner wall of the connected pipeline are all subjected to non-stick treatment.
In the step (1), the molecular weight of the nylon 6 melt generated after the secondary devolatilization is 16500, and the molecular weight distribution is 1.30.
Example 3
Example 3 differs from example 1 in that:
(1) The aperture of the air holes on the devolatilization disc is 1mm;
(2) The hot nitrogen has a water content of 0.5wt%;
(3) The absolute pressure of the devolatilization reaction kettle at the front end is 800Pa, the temperature is 260 ℃, and the retention time is 1.5h. The absolute pressure of the devolatilization reaction kettle at the rear end is below 500Pa, the temperature is 260 ℃, and the retention time is 20min.
(4) The working temperature of the high boiling point component removing tower is 180 ℃, the rotating speed of the helical blade is 80r/min, and the temperature of a pipeline from the high boiling point component removing tower to the low boiling point component removing tower is kept at 90 ℃.
(5) The working temperature of the high boiling point component removing tower is 75 ℃; the spraying medium is caprolactam, and the spraying temperature is 75 ℃. The hot water temperature of the fractionating tower is 75 ℃, and the condensation temperature of the condensing tower is 15 ℃. The vacuum device is independently used by selecting a diffusion jet pump.
(6) The molecular weight of the nylon 6 melt generated after the secondary devolatilization is 18300, and the molecular weight distribution is 1.36.
Example 4
Example 4 differs from example 1 in that:
(1) The aperture of the air holes on the devolatilization disc is 0.9mm;
(2) The hot nitrogen has a water content of 3.9wt%;
(3) The absolute pressure of the devolatilization reaction kettle at the front end is 2600Pa, the temperature is 260 ℃, and the retention time is 1.3h. The absolute pressure of the devolatilization reaction kettle at the rear end is below 500Pa, the temperature is 255 ℃, and the retention time is 22min.
(4) The working temperature of the high boiling point component removing tower is 130 ℃, the rotating speed of the helical blade is 300r/min, and the temperature of a pipeline from the high boiling point component removing tower to the low boiling point component removing tower is kept at 110 ℃.
(5) The working temperature of the high boiling point component removing tower is 78 ℃; the spraying medium was caprolactam and the spraying temperature was 78 ℃. The hot water temperature of the fractionating tower is 75 ℃, and the condensation temperature of the condensing tower is 18 ℃. The vacuum device adopts an injection vacuum pump and is used independently.
(6) The molecular weight of the nylon 6 melt generated after the secondary devolatilization is 19600, and the molecular weight distribution is 1.40.
Example 5
Example 5 differs from example 1 in that:
(1) The aperture of the air holes on the devolatilization disc is 6mm;
(2) The hot nitrogen has a water content of 7wt%;
(3) The absolute pressure of the devolatilization reaction kettle at the front end is 1500Pa, the temperature is 263 ℃, and the retention time is 1.9h. The absolute pressure of the devolatilization reaction kettle at the rear end is below 500Pa, the temperature is 258 ℃, and the retention time is 26min.
(4) The working temperature of the high boiling point component removing tower is 190 ℃, the rotating speed of the helical blade is 50r/min, and the temperature of a pipeline from the high boiling point component removing tower to the low boiling point component removing tower is kept at 99 ℃.
(5) The working temperature of the high boiling point component removing tower is 69 ℃; the spraying medium is caprolactam, and the spraying temperature is 71 ℃. The hot water temperature of the fractionating tower is 72 ℃, and the condensation temperature of the condensing tower is 11 ℃. The vacuum device adopts a diffusion pump and is used independently.
(6) The molecular weight of the nylon 6 melt generated after the secondary devolatilization is 20200, and the molecular weight distribution is 1.44.
The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.
Claims (14)
1. A devolatilization method of a nylon 6 melt is characterized by comprising the following steps:
1) Respectively introducing the nylon 6 melt and hot nitrogen containing water into a devolatilization reaction kettle at the front end through respective channels for devolatilization, removing most of hot water extractables in the nylon 6 melt, mixing the hot water extractables with the hot nitrogen to form a gaseous mixture, discharging the gaseous mixture from the devolatilization reaction kettle, conveying the devolatilized nylon 6 melt to the devolatilization reaction kettle at the rear end for secondary devolatilization without introducing nitrogen, and discharging the nylon 6 melt and the gaseous mixture generated after the secondary devolatilization from the devolatilization reaction kettle respectively;
2) The gaseous mixture is converged and then enters a high boiling point component removing tower, and the high boiling point component in the gaseous mixture is condensed and then discharged from the bottom of the tower and collected;
3) The residual gaseous mixture enters a low boiling point component removing tower, and the low boiling point component in the gaseous mixture falls into the tower bottom to be discharged and collected after the gaseous mixture is sprayed, fractionated and condensed in the rising process; the residual gas is discharged after vacuum treatment;
the devolatilization method is realized by a nylon 6 melt multistage devolatilization device, and the nylon 6 melt multistage devolatilization device comprises a devolatilization system and a component collection system which are sequentially connected;
the devolatilization system comprises a plurality of devolatilization reaction kettles which are connected in series and/or in parallel; the devolatilization reaction kettle comprises a shell, a hollow rotating shaft, a motor and at least one devolatilization disc; the bottom of the shell is provided with a melt inlet and a melt outlet, the middle part of the side surface of the shell is provided with a gas inlet, and the top of the shell is provided with a gas outlet; the hollow rotating shaft is horizontally arranged in the shell, one end of the hollow rotating shaft is communicated with the gas inlet, and the motor is used for driving the hollow rotating shaft to rotate; the devolatilization discs are fixed on the hollow rotating shaft through hollow branch pipes communicated with the hollow rotating shaft, and when a plurality of devolatilization discs are arranged on the hollow rotating shaft in parallel in sequence; pores are distributed on the devolatilization disc; the gas outlet of the devolatilization reaction kettle is connected with a component collecting system;
the component collecting system comprises a high boiling point component removing unit and a low boiling point component removing unit which are connected in sequence;
the high boiling point component removal unit comprises one or more parallel high boiling point component removal columns; the top of each high boiling point component removing tower is respectively provided with an air inlet and an air outlet; a vertical exhaust pipe and a rotatable helical blade which vertically surrounds the outer side of the exhaust pipe and is attached to the inner wall of the high boiling point component removal tower are arranged in the high boiling point component removal tower; the top of the exhaust pipe is communicated with the air outlet, and the bottom of the exhaust pipe is provided with an opening; the bottom of each high boiling point component removing tower is connected with a fine powder receiving tank;
the low boiling point component removal unit comprises one or more low boiling point component removal towers, a recovery tank, a spray tower, a fractionating tower, a condensing tower and a vacuum device which are connected in parallel; each low boiling point component removing tower is internally provided with a rotatable scraper attached to the inner wall of the low boiling point component removing tower, and the recovery tank is connected with the bottom of the low boiling point component removing tower; the spray tower is arranged at the top of the low-boiling-point component removing tower, and a fractionating tower, a condensing tower and a vacuum device are sequentially connected behind the spray tower.
2. The devolatilization method as claimed in claim 1, wherein in step 1), the absolute pressure in said devolatilization reactor at the front end is 500-5000Pa, the temperature is 240-270 ℃, and the residence time of the nylon 6 melt in the devolatilization reactor is 0.5-3h; the absolute pressure in the devolatilization reaction kettle positioned at the rear end is below 500Pa, the temperature is 240-270 ℃, and the residence time of the nylon 6 melt in the devolatilization reaction kettle is 10-30min.
3. The devolatilization process according to claim 1 or 2, characterised in that in step 1) the hot nitrogen has a water content of 0.1 to 10% by weight.
4. The devolatilization process as claimed in claim 1 or 2 wherein in step 1) the nylon 6 melt is maintained at a temperature of 240 to 270 ℃ during the transfer between the different devolatilization reactors and to the high boiling point component removal column.
5. The devolatilization method as claimed in claim 1, wherein in the step 2), the operation temperature of the high boiling point component removal column is 100 to 200 ℃, and the rotation speed of the helical blade provided therein is 10 to 400r/min.
6. The devolatilization method as claimed in claim 1 or 5, wherein in step 2), the temperature of the gaseous mixture is maintained at 80 to 120 ℃ during the transfer from the high boiling point component removal column to the low boiling point component removal column.
7. The devolatilization process as claimed in claim 1 or 5, wherein the operating temperature of the low boiler removal column in step 3) is in the range of 60 to 80 ℃.
8. The devolatilization method as claimed in claim 1 or 5, wherein in step 3),
the spraying medium is water or caprolactam, and the spraying temperature is 60-80 ℃; and/or
The fractionation is hot water fractionation at 70-80 ℃; and/or
The temperature of the condensation is 0-30 ℃.
9. The devolatilization process as claimed in claim 1 wherein said devolatilization reactor has a pore diameter of from 0.1mm to 10mm.
10. The devolatilization process as claimed in claim 1 wherein the devolatilization reactors connected in series and/or in parallel are connected by a melt inlet and a melt outlet and the gas outlets are merged by a pipe.
11. The devolatilization process as claimed in claim 1 wherein the gas inlets of said high boiler removal column are directed horizontally tangentially to the inner wall of said high boiler removal column.
12. The devolatilization process according to claim 1 wherein,
a heating device is arranged on the outer wall of the high boiling point component removing tower; and/or
The bottom of the high boiling point component removing tower is conical with a big top and a small bottom.
13. The devolatilization method as claimed in claim 1 wherein said vacuum means comprises one or a combination of multiple stages in series of rotary vane vacuum pumps, molecular vacuum pumps, jet vacuum pumps, diffusion pumps and diffusion jet pumps.
14. The devolatilization process as claimed in claim 1 wherein the inside walls of said high boiling point component removal column, said helical blades, said low boiling point component removal column, and said flights are treated to be non-stick.
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