Summary of the invention
Main purpose of the present invention is to provide a kind of efficient simplification continuous processing of producing polyethylene terephthalate, and this technology can effectively be boosted productivity, be reduced production costs.
Another object of the present invention is to provide a kind of efficient simplification continuous apparatus of producing polyethylene terephthalate, this device has improved the unreasonable structure of existing production equipment.
The efficient simplification continuous processing of producing polyethylene terephthalate among the present invention mainly includes following operation:
1) esterification raw material ethylene glycol and terephthalic acid were mixed into fresh slurry in 1.6: 1 in molar ratio~1.8: 1, this fresh slurry is sent into a thermal-arrest power cycle and external force to be promoted to carry out esterification in the round-robin hybrid power outer circulation polyester esterification reactor, wherein the temperature of esterification is 256 ℃~275 ℃, and the time of stop is 3-4 hour;
2) material of first esterifier output is imported in second esterifier, the esterification reaction temperature in this second esterifier is 256 ℃-278 ℃, and the reaction times is 1.5 hours, and the esterification yield of output is 96%;
3) will can carry out simultaneously in the Prepolycondensating reactor of esterification and polycondensation by the material input one that the second esterifier esterification is finished, being 272 ℃-276 ℃ in temperature reacted 1.2-2 hour down, wherein esterification yield is 99%, and the limiting viscosity after the polycondensation is 0.22~0.28;
4) will enter one by the material of Prepolycondensating reactor output can form in the final polycondensation reactor of vertical film and parallel membrane, being 282 ℃~286 ℃ in temperature reacted 2-3 hour down, wherein the esterification yield at the polymkeric substance of final polycondensation reactor outlet is 99.8%, the polymerization degree is 90~110, and outlet viscosity is 0.5~0.72.
The above-mentioned the 3rd) to add weight ratio before the step process in the feed-pipe of Prepolycondensating reactor be 10% the outstanding TiO of matting agent
2Supernatant liquid is to obtain the fiber-grade polyester melt in the final polycondensation reactor outlet.
In second esterifier, add m-phthalic acid, to obtain bottle level polyester fondant in the final polycondensation reactor outlet.
The above-mentioned the 2nd) Prepolycondensating reactor that is interconnected and a final polycondensation reactor is set in addition behind the step process, wherein in the feed-pipe of this Prepolycondensating reactor, add weight ratio and be 10% matting agent TiO
2Suspension obtains the fiber-grade polyester melt to export at this corresponding final polycondensation reactor, and obtains a bottle level polyester fondant in the outlet of former final polycondensation reactor.
The efficient simplification continuous apparatus of producing polyethylene terephthalate among the present invention includes first, second esterifier, Prepolycondensating reactor and final polycondensation reactor, wherein:
Described first esterifier is a hybrid power outer circulation type esterifier, it combines the heat power circulation and promotes circulation with mechanical external force, under 256-275 ℃ of temperature, carry out esterification, at this first esterifier internal stops 3-4 hour, the material outlet of this first esterifier bottom was connected with the mistress of described second esterifier;
Mistress and inner room that described second esterifier partly communicates every formation within it, wherein in inner room, be provided with heating agent coil pipe and the whipping appts that drives by external force, in this second esterifier the material from first esterifier is carried out further esterification and handle, wherein esterification yield is 96%;
Described Prepolycondensating reactor is under 272 ℃-276 ℃ the material from second esterifier to be carried out esterification and polycondensation in temperature, and this Prepolycondensating reactor internal stops 1.2-2 hour, wherein the esterification yield in Prepolycondensating reactor is 99%, and limiting viscosity is 0.22-0.28;
In described final polycondensation reactor inside, material can form vertical film and parallel membrane under the whipping appts effect, to increase mass transfer area, and be that 283-286 ℃, pressure are under the 100Pa condition in temperature, finished the poly-reaction of final minification through 2-3 hour, make the limiting viscosity of outputting material bring up to 0.5-0.72, esterification yield is 99.8%, and the polymerization degree is 90-110.
Described first esterifier includes inhomogeneous reaction device, evaporation reaction device and Power Drive Unit, described inhomogeneous reaction device includes the reactor of setting up formula tubulation heat-exchanger rig in one, the outlet of this reactor is connected with described evaporation reaction device, and inlet is connected with the opening for feed of reaction mass and the bottom of evaporation reaction device; Described evaporation reaction device includes an airtight housing, on the top of enclosure interior is evaporating area, and the bottom is a reaction zone, be provided with gaseous phase outlet at its top, the bottom is extended with a diversion section, be provided with at least one flow deflector in this diversion section, this evaporation reaction device and described reactor constitute the loop of a sealing; Described Power Drive Unit includes the driving mechanism that is located at described evaporation reaction device outside, the axial-flow type whipping appts that is hubbed on described diversion section inside, and this axial-flow type whipping appts connects with described driving mechanism by axle.
Be five flow aprons that positive pentagon distributes by being welded with in the described diversion section, and left the space that is used to put described axial-flow type whipping appts middle the blocking of every flow deflector.
Described Prepolycondensating reactor includes a upper cavity and a lower chamber, be provided with the whipping appts that drives by external force in lower chamber inside, upper cavity and lower chamber are isolated cylindrical shell by one and are combined in the airtight housing, described upper cavity is provided with a material inlet, and is provided with heating coil in this upper cavity inside; The top of described lower chamber is provided with exhaust-duct, the bottom of extending outside the described housing and is provided with pipeline and the prepolymer outlet that is communicated with described upper cavity bottom, and the inner bottom part at this lower chamber is provided with heating coil simultaneously; On described isolation cylindrical shell, offer a slit, and this slit place is provided with arc plate toward inner extension of described lower chamber, this arc plate forms one with described isolating cylinder body and is used to be communicated with the crooked swirling flow passage of described upper cavity and lower chamber, and is provided with one at described slit place and is used to regulate the variable valve of slit size.
The side that described upper cavity inside is positioned at slit is provided with one and is used for the flow deflector that pilot-gas flows to.
Described final polycondensation reactor includes the rounded or oblong pressure-bearing type cylindrical shell of cross section of a sealing, this cylindrical shell is provided with material inlet and material outlet, and be pivoted with a drive shaft in inner barrel, the center of circle that is centered close to cylindrical shell of this drive shaft or down round center, be installed with many group ring dishes on this drive shaft, wherein said ring dish is installed with the parallel axial membrane steel plate of polylith at its sidepiece.
The production technique of producing polyethylene terephthalate among the present invention adopts two sections esterifications and two sections polycondensation processes with device, makes whole technology have the advantage that simple and direct, the every technical indicator of flow process all is better than same device.
Embodiment
Below in conjunction with accompanying drawing the specific embodiment among the present invention is described in further detail.
As shown in Figure 1, the efficient simplification continuous apparatus of production polyethylene terephthalate includes the first esterifier A, the second esterifier B, Prepolycondensating reactor C and final polycondensation reactor D among the present invention.
As shown in Figure 3, the first esterifier A is a hybrid power outer circulation type polyester esterification reactor, includes inhomogeneous reaction device 1, evaporation reaction device 2 and Power Drive Unit 3, wherein:
Evaporation reaction device 2 includes an airtight housing 20, outside housing 20, be provided with a liquid phase heating agent chuck 26 with heat insulation function, these housing 20 inside can be divided into the evaporating area 21 on top and the reaction zone 22 of bottom in reaction process, be provided with gaseous phase outlet 23 at its top, the bottom is extended with a diversion section 24 in integrally formed mode, be provided with five by welding or other fixedly connected mode on the inwall of this diversion section 24 and be the baffle plate 25 that positive pentagon distributes, and each baffle plate 25 is all by the space of blocking and being formed for putting axial-flow type whipping appts 30, utilize this baffle plate 25 can destroy liquid formed whirlpool under 30 effects of axial-flow type whipping appts, thereby guarantee that liquid is toward current downflow.
Inhomogeneous reaction device 1 includes the reactor 10 that an inside is provided with vertical tubulation heat-exchanger rig 16, the outlet of this reactor 10 is connected with the evaporating area 21 on evaporation reaction device 2 tops by water conservancy diversion top cover 11, inhomogeneous reaction thing outlet pipe 12, inlet 17 is a guiding cone of standing upside down, and has the function of homogeneous mixture of material.This inlet 17 is connected by the diversion section 24 of a U-shaped pipe 14 with evaporation reaction device 2 bottoms, thereby constitute the loop of a sealing by inhomogeneous reaction device 1 and evaporation reaction device 2, end at U-shaped pipe 14 close reactor 10 inlets 17 is provided with a material inlet 13, is provided with a material outlet 15 at the end near evaporation reaction device 2.The entry and exit 18,19 of vertical tubulation heat-exchanger rig 16 are connected with extraneous liquid phase heating agent heating tube (not shown), utilize the liquid phase heating agent can the material that enter reactor 10 inside be heated.In order to prevent the loss of heat, also be arranged with liquid phase heating agent chuck with the outside of inhomogeneous reaction thing outlet pipe 12 with heat insulation function at reactor 10, U-shaped pipe 14, top cover 11.
Power Drive Unit 3 includes the driving mechanism 31 that is located at evaporation reaction device 2 tops, parallel two the axial-flow type whipping apptss 30 (also can be one or more) that are hubbed on evaporation reaction device diversion section 24 inside by same axle 32 drivings, this axial-flow type whipping appts 30 connects with driving mechanism 31 by axle 32, and in the junction of axle 32 and housing 20 for being tightly connected.
As depicted in figs. 1 and 2, the second esterifier B includes a housing 4, these housing 4 inside are divided into mistress 41 and inner room 42 by an inner core 40, wherein mistress 41 is connected with the material outlet 15 of the first esterifier A, in inner room 42, be provided with heating agent heating coil 43 and the whipping appts 44 that drives by external force, heating coil 43 is connected with extraneous liquid phase heating agent, and can carry out heat exchange to material.Inner room 41 bottoms of this second esterifier B are connected with the material inlet 510 of Prepolycondensating reactor C upper cavity.
As shown in Figure 4 and Figure 5, Prepolycondensating reactor C includes an airtight housing 5, this housing 5 portion within it is separated into upper cavity 51 that is atmospheric pressure state and the lower chamber 52 that is vacuum state by an isolation cylindrical shell 50, wherein upper cavity 51 is around in the top in lower chamber 52 outsides, and being provided with a whipping appts 53 in lower chamber 52 inside, this whipping appts 53 is driven by axle 54 and the drive unit 55 that is located at housing 5 tops.
Upper cavity 51 is provided with a material inlet 510 and a material outlet 511, and wherein material inlet 510 is connected with inner room 42 bottoms of the second esterifier B by pipeline, and the inner bottom part at upper cavity 51 is provided with one group of heating coil 56 simultaneously.Lower chamber 52 is provided with a pre-polymerization material outlet 520 and a material inlet 521, wherein pre-polymerization material outlet 520 is connected with final polycondensation reactor D by pipeline, material inlet 521 is connected by the material outlet 511 of pipeline 57 with upper cavity 51 bottoms, and this pipeline 57 is provided with a variable valve 58, be used for controlling flow from upper cavity 51 input lower chambers 52 materials, thereby control the liquid level difference in the upper and lower cavity 51,52, make reactor production steady.Lower chamber 52 is provided with an exhaust-duct 59 of extending outside the housing 5 at an upper portion thereof, as shown in Figure 4, the gas that reaction produces in lower chamber 52 and the upper cavity 51 is input in the exhaust gas processing device by this exhaust-duct 59, offering one simultaneously on isolation cylindrical shell 50 is used for being communicated with, lower chamber 51,52 slit 500, and be extended with an arc plate 501 toward the inside that isolates cylindrical shell 50 at these slit 500 places, as shown in Figure 5, this arc plate 501 forms an ascending crooked swirling flow passage 502 with isolation cylindrical shell 50 inwalls, be provided with in addition a variable valve 502 that is used to control slit 500 sizes, be further used in the control at slit 500 places, lower chamber 51, pressure between 52.This variable valve 503 extends housing 5 tops, and is located at the top of housing 5.
As shown in Figure 5, a side that is positioned at slit 500 in upper cavity 51 inside is provided with a flow deflector 504, utilize this flow deflector 504 that upper cavity 51 gas inside are flowed along assigned direction, and enter in the crooked swirling flow passage 502, utilize the setting of this flow deflector 504 and crooked swirling flow passage 502, can effectively strengthen separating of gas phase and liquid phase, make gas phase enter exhaust gas processing device by exhaust-duct 59, liquid phase then falls into lower chamber 52 and carries out polycondensation.
As shown in Figure 6 and Figure 7, final polycondensation reactor D includes an airtight rounded or oblong cylindrical shell 6 of cross section, this cylindrical shell 6 is horizontal setting, and be provided with a material inlet 60 and a material outlet 61 respectively at both ends, this reactor also includes one makes air communication cross the air feeder (not shown) of inside reactor, to utilize air-flow to take away ethylene glycol and water molecules fast,, no longer describe in detail at this because this part-structure is a prior art.Be pivoted with a hollow drive shaft 62 of being used to wear whole cylindrical shell 6 between the end cap at cylindrical shell 6 both ends, this drive shaft 62 is positioned at the center of circle of cylindrical shell 6 or circle centre position down, and the one end extends cylindrical shell 6 backs and connects with transmission mechanism, motor, and by electric motor driving.Parallel being installed with in position that is positioned at cylindrical shell 6 inside at drive shaft 62 organized ring dishes 63 more, as shown in Figure 7, the centre of this ring dish 63 is provided with the perforation 64 that a plurality of equal angles distribute, and between two perforation 64, form a ribs 65, on each ribs and ring dish, be welded with the axial membrane steel plate 66 of polylith, on the inwall of cylindrical shell 6, adopt slot to be connected with the scraper plate (not shown) simultaneously, control the thickness of liquid film 67 by adjusting scraper plate and the gap between axial membrane steel plate 66, the ring dish 63, and form vertical film and axial membrane, increase mass transfer area.
The production process of the device of production polyethylene terephthalate is as follows among the present invention:
Raw material EG and PTA are mixed with fresh oar material by certain mol proportion at 1.7: 1, material inlet 13 by reactor 10 bottoms adds, after circulation oar material mixes, enter reactor 10, carry out heat exchange with the vertical tubulation heat-exchanger rig 16 of reactor 10 inside, the oar material is heated, temperature raises, esterification takes place, part ethylene glycol vaporization in esterification, therefore form the lower gas-liquid mixed phase of density on reactor 10 tops, under the promotion of density difference, material is via the water conservancy diversion top cover 11 on top, inhomogeneous reaction thing outlet pipe 12 enters the evaporating area 21 of evaporation reaction device 2, produces gas-liquid separation, oar material and the ethylene glycol generation esterification of not vaporizing generate carboxylate and water.Water and unnecessary ethylene glycol part vaporization at high temperature, the gas phase of ethylene glycol and water is discharged by the gaseous phase outlet 23 at evaporation reaction device 2 tops, enters tail gas treatment process tower 7.And liquid phase enters the reaction zone 22 of evaporation reaction device 2 bottoms, proceeds reaction and gas-liquid separation.The material that part has been finished esterification imports the second esterifier B through reaction zone 22 bottom material outlets 15, and the material of part enters circulation next time again with after fresh oar material mixes.
The material of having finished esterification imports the mistress 41 of the second esterifier B from material outlet 15, behind inner core 40 1 circles, enter inner room 42 through slit, in inner room 42, carry out heat exchange with heating coil 43, and stir by 44 pairs of materials of whipping appts, carry out esterification, the oligopolymer of finishing after the esterification is discharged by the bottom, and water that generates in reaction process and excessive ethylene glycol are discharged from the top with gas phase state and sent into process tower and handle.
Water of being discharged by first and second esterifier A, B top and ethylene glycol steam enter process tower 7 and carry out separating treatment, and the ethylene glycol of separating at the bottom of the tower is introduced first and second esterifier A, B recycling.Water and the noncondensable gas separated from cat head enter reflux exchanger 70, and noncondensable gas is sent into tail gas tower and handled, and a water of condensation part refluxes, and another part send waste disposal plant 71 to handle.
Material after the second esterifier B esterification enters in the upper cavity 51 of Prepolycondensating reactor C, flow and carry out heat exchange along phase with heating coil 56 in the upper cavity 51, wherein liquid phase from upper cavity 51 via pipeline 56, under the control of variable valve 58, flow into lower chamber 52, in lower chamber 52, continue to carry out heat exchange, and under the effect of whipping appts 53, carry out polycondensation with heating coil 520.Gas phase in the material is ethylene glycol and other volatiles that devolatilization is come out in the reaction, they are entering lower chamber 52 from upper cavity 51 by crooked swirling flow passage 502 under the effect of pressure difference 2000-4000pa under the control of variable valve 503, separate the removal entrained drip through rotation, the gas that junction lower chamber 52 is evaporated together enters vacuum system from gaseous phase outlet 59.
Liquid phase material in the Prepolycondensating reactor C is discharged by pre-polymerization material outlet 520, sends into final polycondensation reactor D with pump 9, material from enter the mouth 60 enter reactor after, under the effect of separable ring dish whipping appts, carry out polycondensation.It is membranaceous that material is formed, help the ethylene glycol liquid polymer of from the continuous replacement process of film, overflowing, polycondensation is carried out to the deeper degree direction, owing in reactor, form a kind of film (abbreviation vertical film) perpendicular to air flow line in the reactor, be parallel to the film (abbreviation parallel membrane) of air flow line in the reactor with another kind, thereby increased the amount of unit whipping appts action space belongings feed liquid film, make the reactor mass transfer area increase, the probability that ethylene glycol is deviate from improves, and effectively raises stirring efficiency.The ethylene glycol of deviating from from liquid phase enters spray condenser 8 through gaseous phase outlet, and after cold liquid glycol direct heat exchange condensation, ethylene glycol enters the ethylene glycol receiving tank, and noncondensable gas enters vacuum system.
In above-mentioned reaction process, the heating coil in each reactor is connected with liquid phase heating agent house steward E10, E11, E20, the E21 in the external world respectively, and sufficient amount of heat is provided.
Utilize said apparatus can realize producing the kinds of processes of the polyethylene terephthalate that is fit to different purposes, enumerate different embodiment below respectively and be illustrated.
Embodiment one
As shown in Figure 1, the concrete technology of production polyethylene terephthalate is as follows:
1) esterification raw material ethylene glycol and terephthalic acid were mixed into fresh slurry in 1.6: 1 in molar ratio, this fresh slurry is sent into a thermal-arrest power cycle and external force to be promoted to carry out esterification in the round-robin hybrid power outer circulation polyester esterification reactor, wherein the temperature of esterification is 256 ℃~275 ℃, and the time of stop is 3-4 hour;
2) material of first esterifier output is imported in second esterifier, the esterification reaction temperature in this second esterifier is 256 ℃-278 ℃, and the reaction times is 1.5 hours, and the esterification yield of output is 96%;
3) will can carry out simultaneously in the Prepolycondensating reactor of esterification and polycondensation by the material input one that the second esterifier esterification is finished, being 272 ℃-276 ℃ in temperature reacted 1.2-2 hour down, wherein esterification yield is 99%, and the limiting viscosity after the polycondensation is 0.22~0.28;
4) will enter one by the material of Prepolycondensating reactor output can form in the final polycondensation reactor of vertical film and parallel membrane, being 282 ℃~286 ℃ in temperature reacted 2-3 hour down, wherein the esterification yield at the polymkeric substance of final polycondensation reactor outlet is 99.8%, the polymerization degree is 90~110, and outlet viscosity is 0.5~0.72.
Embodiment two
As shown in Figure 2, it is as follows to produce the technology of the fibre-grade polyethylene terephthalate be used to weave:
1) esterification raw material ethylene glycol and terephthalic acid were mixed into fresh slurry in 1.65: 1 in molar ratio, this fresh slurry is sent into a thermal-arrest power cycle and external force to be promoted to carry out esterification among the round-robin hybrid power outer circulation polyester esterification reactor A, wherein the temperature of esterification is 260 ℃~270 ℃, and the time of stop is 3.5 hours;
2) material of first esterifier A output is imported in the sub-B of second esterifier, the esterification reaction temperature in this second esterifier B is 260 ℃-275 ℃, and after 1.5 hours reaction times, the esterification yield of outputting material is 96%;
3) the material input one that will be finished by the second esterifier B esterification can be carried out among the Prepolycondensating reactor C of esterification and polycondensation simultaneously, and the adding weight ratio is that (matting agent is TiO for 10% matting agent in equipment before material input Prepolycondensating reactor C or the pipeline simultaneously
2) suspension, being 275 ℃-268 ℃ in temperature and reacting 1.5 hours down that wherein the esterification yield in Prepolycondensating reactor C is 99%, the limiting viscosity of material is 0.22~0.28 after the polycondensation;
4) will enter one by the material of Prepolycondensating reactor C output can form in the final polycondensation reactor D of vertical film and parallel membrane, being 285~286 ℃ in temperature reacted 3.5 hours down, obtain the fiber PET melt that can be used for weaving in this final polycondensation reactor D outlet, the esterification yield of this PET melt is 99.8%, the polymerization degree is 90~110, and outlet viscosity is 0.5~0.72.
Embodiment three
As shown in Figure 2, the efficient simplification continuous processing of producing the polyethylene terephthalate be used to make bottle among the present invention comprises following operation:
1) esterification raw material ethylene glycol and terephthalic acid were mixed into fresh slurry in 1.8: 1 in molar ratio, this fresh slurry is sent into a thermal-arrest power cycle and external force to be promoted to carry out esterification among the round-robin hybrid power outer circulation polyester esterification reactor A, wherein the temperature of esterification is 256 ℃~275 ℃, and the time of stop is 3-4 hour;
2) material of first esterifier A output is imported in the second esterifier B, add m-phthalic acid (IPA) at the top of this second esterifier B simultaneously, make material in second esterifier, carry out further esterification, esterification reaction temperature in this second esterifier B is 256 ℃-278 ℃, reaction times is 1.5 hours, and the esterification yield of outputting material is 96%;
3) will can carry out among the Prepolycondensating reactor C of esterification and polycondensation simultaneously by the material input one that the second esterifier B esterification is finished, being 272-276 ℃ in temperature in Prepolycondensating reactor C reacted 1.2-2 hour down, wherein the esterification yield in this Prepolycondensating reactor C is 99%, and the limiting viscosity of material is 0.22~0.28 after the polycondensation;
4) will enter one by the material of Prepolycondensating reactor C output can form in the final polycondensation reactor D of vertical film and parallel membrane, being 282~286 ℃ in temperature reacted 3-4 hour down, go out to obtain a bottle level polyester fondant at this final polycondensation reactor D, the esterification yield of this polyester fondant is 99.8%, the polymerization degree is 90~110, and outlet viscosity is 0.5~0.72.
Embodiment four
As shown in Figure 2, technology among this embodiment substantially with embodiment three in identical, its difference only is at embodiment 3 the 3rd) one group of Prepolycondensating reactor C ' in parallel, final polycondensation reactor D ' before the step process, make by the material of exporting among the second esterifier B to enter respectively among two groups of Prepolycondensating reactor C, C ', final polycondensation reactor D, the D ', and to add weight ratio in the feed-pipe of one group of anti-device C ' of precondensation be that (matting agent is TiO for 10% matting agent
2), so can obtain fiber level PET melt, and obtain the bottle level PET melt in the outlet of final polycondensation reactor D in the exit of this final polycondensation reactor D '.In the glycol recovery treating processes of Prepolycondensating reactor C ', have additional a TiO in addition
2Strainer 80 utilizes this TiO
2Strainer can effectively be removed the TiO in the ethylene glycol tail gas
2, make and to reuse in the esterification reaction process of the first esterifier A through the ethylene glycol after the vent gas treatment.
In sum, the efficient simplification continuous processing and the device of production polyethylene terephthalate have the following advantages among the present invention:
1. the esterification part makes the esterification yield of second esterifier outlet reach more than 96% owing to adopt first and second esterifiers, the esterification smooth operation, and content of carboxyl end group is easy to control.
2. because first esterification reaction process has adopted a kind of hybrid power outer circulation type esterifier, and because this reactor has rationally solved the heat power circulation and external force promotes the round-robin fit scale, reduced the internal circulating load of ethylene glycol, rationally use the energy, make device both save the energy, reduce equipment volume again, reduce under the situation of cost, reach the purpose that polyester device maximizes.
3. because the esterification yield height, make precondensation section lactonization reaction ratio descend greatly, the water yield that reaction generates seldom, so can adopt with ethylene glycol is the airless injection system of power steam, this injection system has advantages such as energy consumption is low, the EG reuse convenient, and quantity of wastewater effluent is few.
In polycondensation part owing to adopt Prepolycondensating reactor and final polycondensation reactor, make precondensation outlet limiting viscosity reach 0.22~0.28, satisfy the requirement that directly enters final polycondensation reactor.
5. owing to adopted Prepolycondensating reactor, make and produce steadily that control is simple with special construction.
6. because the use of final polycondensation reactor, can form film (abbreviation vertical film) perpendicular to air flow line in the reactor, with the film that is parallel to air flow line in the reactor (abbreviation parallel membrane), increased the amount of unit whipping appts action space belongings feed liquid film, increase the reactor mass transfer area, effectively raised stirring efficiency.