Title of Invention

A PRE-POLYCONDENSATION REACTOR

Abstract

ABSTRACT The present invention relates to a novel pre-polycondensation reactor having a double-chamber upright structure, comprising an upper chamber (6), a lower chamber (7) and an external actuating device (200), wherein said upper chamber comprises an inlet (1) of materials, an upper chamber outlet (9) of materials, an upper chamber heater (14) within the upper chamber, and an upper-lower chamber liquid phase tube (4) connecting the upper chamber (6) with the lower chamber (7); said lower chamber comprises a lower chamber inlet (10) of materials, located in the upper part of this chamber an exhaust passage (21) extending outside said reaction container (100), an outlet (5) of prepolymers, and a lower chamber heater (13); wherein the upper chamber (6) and lower chamber (7) of said polycondensation reactor are combined within a closed reaction container (100) by an upper-lower chamber separator (17).

Full Text

FPCH05160064 NOVEL PRE-POLYCONDENSATION REACTOR TECHNICAL FIELD The present invention relates to a novel pre-polycondensation reactor for the production of prepolymers, especially to a new pre-polycondensation reactor for the production of polyethylene glycol terephthalate (PET) prepolymers. BACKGROUND ART According to a conventional polycondensation method for producing polyethylene glycol terephthalate (PET), an esterified substance is subjected to two stages including a pre-polycondensation stage and final polycondensation stage. Said pre-polycondensation stage is a transition stage of materials from esterification to polycondensation, in which stage oligomers from the esterification stage complete esterification, the esterification rate being raised to 99% or higher, and in the meanwhile polycondensation starts. As pressure in the pre-polycondensation process undergoes a decompressing process from positive pressure to vacuum, in most cases two independent reactors are employed to complete the pre-polycondensation process, or a tower-type reactor is used to treat such a decompressing technology. However, because two independent pre-polycondensation reactors have to be employed to realize the pre-polycondensation process, there arises many problems such as over-procedure, to many controll points, occupation of a large area, increase of the daily operation cost, and a heavy investment. Using a tower-type reactor for completing a pre-polycondensation process is reasonable with respect to the reaction mechanism, but it is known from industrial practice that this kind of reactor consumes too much metal material, requires a long reaction process and yields a lot of unreacted materials when it stops (discharging a large amount of waste material), thus also causing a lot of problems such as a heavy vestment at the same time, over consumption, a high cost and the like. Generally, the average polymerization degree at the outlet of a general pre-polycondensation reactor is from 20 to 30. Since the pressure of a pre-polycondensation undergoes a decompressing process from positive pressure to vacuum, two independent reactors are employed in most of the technologies to complete the pre-polycondensation process. There are also some manufacturers using a tower-type reactor to dealing with this decompressing process. A two-stage pre-polycondensation reactor requires many controlling points, occupies a large area and has an increased operation cost; while two reactors needs a large investment at the very beginning of construct. The novel pre-polycondensation reactor of this invention does not have the disadvantages of the above two kinds of reactors. Instead, it has a simplified process, needs a lower investment, consumes less , requires a lower daily operation costs and is easy to operate and produces products with brilliant quality. CONTENTS OF THE INVENTION An object of this invention is to provide a novel pre-polycondensation reactor, which can complete pre-polycondensation with only one reactor, thus solving the problems that a two-stage pre-polycondensation reactor in the existring technology has, namely many control points, a occupation of big area, a high of operation cost and a huge investment at the same time. It also solves the problems that a tower-type reactor in the existring technology has, namely a high consumption of metal materials, a long reaction process, much wastes result from it is shutdown, a huge investment at the same time and a high consumption. The novel pre-polycondensation reactor of this invention has a upright structure with double-chambers, comprising an upper chamber, a lower chamber and an external actuating device, wherein: Said upper chamber comprises an inlet of materials, an upper chamber outlet of materials, an upper chamber heater within the upper chamber, and an upper-lower chamber liquid phase HTM line tube connecting the upper chamber with the lower chamber; Said lower chamber comprises a lower chamber inlet of materials, an exhaust passage venting outside said reaction located in the upper part of this chamber , an outlet of prepolymers, and a lower chamber heater; Wineries the upper chamber and lower chamber of said polycondensation reactor are combined within a closed reaction container by an upper-lower chamber separator. In a preferable embodiment of this invention, there is an additional ring-shape vapor phase diversion orifice on the upper-lower chamber separator. In another preferable embodiment of this invention, there is a damping cavity at the place where the upper part of the lower chamber is connected to the upper chamber, wherein several damping plates are set in the damping cavity. In another preferable embodiment of this invention, said upper chamber heater is a cylindrical heater. In another preferable embodiment of this invention, said lower chamber heater is a plate-type heater. In another preferable embodiment of this invention, there is a gas cone in the lower part of the venting passage, which extends outside the reactor, in the lower chamber of the polycondensation reactor. In another preferable embodiment of this invention, said external actuating device of the polycondensation reactor comprises an agitator, a agitating blade, a seal, and a shaft. In another preferable embodiment of this invention, the agitator of the said external actuating device is located outside the bottom of the lower chamber. In another preferable embodiment of this invention, a vapor phase thermal media is used in the upper chamber heater of the polycondensation reactor. In another preferable embodiment of this invention, a vapor phase thermal media is used in the lower chamber heater of the polycondensation reactor. In another preferable embodiment of this invention, the said polycondensation reactor further comprises an insulating-heating unit for reactor. In another preferable embodiment of this invention, a vapor phase thermal media is used in the insulating-heating unit for the said polycondensation reactor. In another preferable embodiment of this invention, there is a control valve in liquid phase line of the upper-lower chamber of the polycondensation reactor. The pre-polycondensation reactor of this invention has a simplified structure. Pre-polycondensation can be completed with only one reactor. Besides, it is simple to operate and easy to control and can ensure a stable operation. DESCRIPTION OF DRAWINGS Fig. 1 is a vertical profile of a preferable embodiment of the pre-polycondensation reactor of this invention. Fig. 2 is a horizontal section profile of a preferable embodiment of the pre-polycondensation reactor of this invention. MODES FOR CARRYING OUT THE INVENTION Hereinafter are detailed illustrations of the pre-polycondensation reactor of the present invention in accordance with the figures, but can never be construed as limit of the pre-polycondensation reactor of the present invention. As shown in Fig.l and Fig.2, the novel pre-polycondensation reactor of this invention is an upright device having double-chamber structure, comprising a closed reactor 100, an upper chamber 6 and a lower chamber 7 which are combined within the closed reactor by an upper-lower chamber separator 17, wherein the upper chamber 6 is located on the top of the outside of the lower chamber 7, the upper chamber is a flash distillation chamber, the operation pressure being crude vacuum, and the lower chamber is a polycondensation chamber, the operation pressure being low vacuum. Outside the reaction container 100 there is an insulating-heating unit 16 of the reaction container. Preferably, a vapor phase thermal media is used in said insulating-heating unit 16 of the reactor. Moreover, there is an external actuating device 200 at the bottom of the lower chamber. The said upper chamber 6 comprises an inlet 1 of materials at its lower part, an upper chamber outlet 9 of materials, an upper chamber heater 14 at the bottom of said upper chamber and an upper-lower chamber liquid phase tube 4. The upper chamber outlet 9 of materials is connected to a lower chamber inlet 10 of material of the lower chamber 7 via the upper-lower chamber liquid phase line 4, such that liquid materials of the upper chamber flow from the upper chamber outlet 9 of materials, through the upper-lower chamber liquid phase line 4, into the lower chamber 7 via the lower chamber inlet 10 of materials. Besides, in the upper-lower chamber liquid phase tube 4 there is a regulating valve 300 for controlling the rate of materials flowing from the upper chamber 6 into the lower chamber 7, thus controlling the liquid level in the upper chamber 6 and the lower chamber 7 to simplify control of the reactor and to make production stable. Preferably, the upper chamber heater 14 is a calandria heater, providing heat for the upper chamber by use of a vapor phase thermal media. Moreover, because esterification and polycondensation are carried out simultaneously in the upper chamber, a discharge of the gas produced may facilitate proceeding of the reaction. Therefore, preferably, the gas produced is continuously discharged out of the pre-polycondensation reactor through an exhaust passage 21 via a rig-shape vapor phase diversion orifice 2. Said lower chamber 7 comprises located in the upper part of this chamber an exhaust passage 21 extending outside said reaction container, a lower chamber inlet 10 of materials, an outlet 5 of prepolymers, a lower chamber heater 13 and an external actuating device 200. With the venting passage 21 extending outside said reaction container at the upper part, the gas produced by the reaction in the upper chamber 6 and the lower chamber 7 are discharged out of the reactor. The product is discharged out of said pre-polycondensation reactor via the outlet 5 of prepolymers. The lower chamber heater 13 at the bottom of the lower chamber is preferably a plate-type heater. This heater has a shape of a ring, and its inner part is divided into multi-layer ring-shape channels, so that the thermal media has sufficient flow rate within the heater and the heat transfer rate is increased. Said heater preferably uses a vapor phase thermal media. The said external actuating device 200 comprises an actuating device for agitator 204, a agitator blade 201, a seal 203 and a shaft 202. Since the reaction of the materials in the upper chamber 6 of the pre-polycondensation reactor is conducted under a gradually decompressing condition, under the influence of the pressure difference, the materials are in a boiling state after entering into the upper chamber 6 of the reactor. The materials are mixed by their own boiling, and are stirred by the bubble occurring process. Therefore, there is no need to set an external actuating device. When the materials enter into the lower chamber 7 of the reactor, as the intrinsic viscosity of the materials is increased, the gas produced needs to be excluded under a mechanical stirring state, so as to facilitate continuation of the reaction. Therefore, an external actuating device 200 for materials having a relatively high viscosity is set in the lower chamber 7 of the pre-polycondensation reactor. Preferably, the actuating device for agitator 204 located at the bottom of the lower chamber 7 and outside the reaction container 100 actuates the agitator blade 201 via a stirrer shaft 202 to carry out agitator. The agitator blade 201 is a wall-scraping type agitator blade, which may make the material fluid flow downward at the edge of the reactor, thus increasing the area in which the volatile substances are removed from the materials and also improving the renewal of materials on the walls of the reactor. The external actuating device at the bottom of the lower chamber 7, as compared to an external actuating device set on the top, has a shorter shaft, swings little during agitator and, at the same agitator power, may achieve a better agitator efficiency. Preferably, there is a ring-shape vapor phase diversion orifice 2 on the upper-lower chamber separator, making the gas in the upper chamber 6 flow following a given direction. Preferably, there is still a damping cavity 19 at the place where the upper part of the lower chamber is connected to the upper chamber, wherein several damping plates 18 are set in the damping cavity 19. The damping cavity 19 is a key element for maintaining the pressure difference between the upper and lower chambers. The high-speed gas stream flows into the lower chamber 7 after passing several damping plates 18 and is decompressed. The gas-liquid separation makes the liquid drops fall into the liquid phase of the lower chamber. As shown in Fig. 1, because the evaporation of the gas produced by the reaction needs a large amount of heat, a calandria heater 14 and a plate-type heater 13 using a vapor phase thermal media are applied in the upper chamber 6 and the lower chamber 7, respectively. Preferably, said polycondensation reactor further comprises an insulating-heating unit 16 of the reaction container, a vapor phase thermal media being used in said insulating-heating unit of the reaction container. As shown in Fig.l, the vapor phase thermal media enters into said polycondensation reactor via an inlet 11 of thermal media, and is discharged out of said polycondensation reactor via an outlet 12 of thermal media. The pre-polycondensation reaction of the present invention has a simple and novel structure, involves a concise technology, may complete pre-polycondensation using only one reactor, and overcomes the defects present in the existing technology. The product has an intrinsic viscosity of up to 0.20 to 0.29, fully satisfying the requirements of a pre-polycondensation process. Besides, this reactor of the present invention is simple to operate and easy to control, and ensures a stable operation. The specific embodiments of the present mentions are further illustrated in detail with the example where pre-polycondensation is conducted, using an ethylene glycol terephthalate (BHET) having an esterification rate of 96% as the raw material, to produce prepolymers of polyethylene glycol terephthalate. The ethylene glycol terephthalate (BHET) having an esterification rate of 96% was introduced via the inlet 1 of materials into the upper chamber 6 of the pre-polycondensation reactor, the operation pressure in the upper chamber being crude vacuum, circumferentially flowed along the side and was heated by the calandria heater 14, which supplied heat using a vapor phase thermal media. Esterification and polycondensation were carried out simultaneously. After ethylene glycol was vaporized, under the effect of the pressure difference, the gas passed the damping cavity 19 having several damping plates 18 via the ring-shape vapor phase diversion orifice 2, was decompressed and entered into the lower chamber 7 wherein the operation pressure was vacuum. By use of the damping plates 18, the pressure difference between the upper and lower chambers was controlled with in the range of from 15 mbar to 50 mbar. After the gas produced entered into the lower chamber 7, the liquid drops it carried fell into the liquid of the lower chamber. The gas entering into the lower chamber met with the evaporated gas of the lower chamber, and was discharged out of the pre-polycondensation reactor 100 by the gas cone 20 through the exhaust passage 21 extending out of said reactor container from the upper part of the lower chamber. The liquid phase materials obtained flowed from the upper chamber outlet 9 of materials, through the upper-lower chamber liquid phase tube 4 of the upper chamber 6 of the reactor via the regulating valve 300, into the lower chamber 7 via the lower chamber inlet 10 of materials. Said materials were heated by the plate-type heater 13 of the lower chamber in lower chamber 7, which supplied heat using a vapor phase thermal media, and was further reacted as actuated by the external actuating device 200 of the lower chamber. The materials were pre-condensed at 270°C to 278°C. The total residue time of the materials in the pre-polycondensation reactor may be controlled within 60 to 110 min. The products obtained from the reaction were discharged out of the pre-polycondensation reactor from the outlet 5 of prepolymers. Since the reaction of the materials in the upper chamber of the pre-polycondensation reactor was conducted under a gradually decompressing condition, under the influence of the pressure difference, the materials were in a boiling state after entering into the upper chamber of the reactor. The materials were mixed by their own boiling, and were stirred by the bubble occurring process. Therefore, there was no need to set an agitator. When the materials entered into the lower chamber of the reactor, as the intrinsic viscosity of the materials was increased, the ethylene glycol gas produced needed to be excluded under a mechanical agitator state, so as to facilitate continuation of the reaction. Therefore, an external actuating device 200 for materials having a relatively high viscosity was set in the lower chamber of the reactor. The actuating device for agitator located at the bottom of the lower chamber 7 and outside the reaction container 100 actuated the blade 201 via the stirrer shaft 202 to carry out agitation of the materials. As evaporation of ethylene glycol produced by the reaction needed a large amount of heat, the polycondensation reactor comprised an insulating-heating unit 16 using a vapor phase thermal media. CLAIMS 1. A novel pre-polycondensation reactor having a double-chamber upright structure, comprising an upper chamber (6), a lower chamber (7) and an external actuating device (200), characterized in that: said upper chamber (6) comprises an inlet (1) of materials, an upper chamber outlet (9) of materials, an upper chamber heater (14) within the upper chamber, and an upper-lower chamber liquid phase tube (4) connecting the upper chamber (6) with the lower chamber (7); said lower chamber (7) comprises a lower chamber inlet (10) of materials, located in the upper part of this chamber an exhaust passage (21) extending outside said reaction container (100), an outlet (5) of prepolymers, and a lower chamber heater (13); wherein the upper chamber (6) and lower chamber (7) of said polycondensation reactor are combined within a closed reaction container (100) by an upper-lower chamber separator (17). 2. The pre-polycondensation reactor according to claim 1, characterized in that said external actuating device (200) is located at the bottom of the lower chamber (7). 3. The pre-polycondensation reactor according to any of the preceding claims, characterized in that said upper-lower chamber separator (17) further comprises a ring-shape vapor phase diversion orifice (2). 4. The pre-polycondensation reactor according to any of the preceding claims, characterized in that there is a damping cavity (19) at the place where the upper part of the lower chamber is connected to the upper chamber, wherein several damping plates (18) are set in the damping cavity (19). 5. The pre-polycondensation reactor according to any of the preceding claims, characterized in that there is a gas cone (20) in the lower part of the exhaust passage (21) which extends outside the reaction container in said lower chamber. 6. The pre-polycondensation reactor according to any of the preceding claims, characterized in that said external actuating device 200 comprises an actuating device for stirring (204), a stirrer blade (201), a seal (203) and a stirrer shaft (202). 7. The pre-poly condensation reactor according to any of the preceding claims, characterized in that said upper chamber heater (14) is a calandria heater. 8. The pre-polycondensation reactor according to any of the preceding claims, characterized in that said lower chamber heater (13) is a plate-type heater. 9. The pre-polycondensation reactor according to any of the preceding claims, characterized in that a vapor phase thermal media is used in said upper chamber heater (14). 10.The pre-polycondensation reactor according to any of the preceding claims, characterized in that a vapor phase thermal media is used in said lower chamber heater (13). 11. The pre-polycondensation reactor according to any of the preceding claims, characterized in that further comprising an insulating-heating unit (16) of the reaction container. 12. The pre-polycondensation reactor according to any of the preceding claims, characterized in that a vapor phase thermal media is used in said insulating-heating unit (16) of the reaction container. 13. The pre-polycondensation reactor according to any of the preceding claims, characterized in that there is a regulating value (300) in the upper-lower chamber liquid phase tube (4).

Documents:

3277-CHENP-2008 AMENDED CLAIMS 15-09-2014.pdf

3277-CHENP-2008 AMENDED PAGES OF SPECIFICATION 15-09-2014.pdf

3277-CHENP-2008 CORRESPONDENCE OTHERS 29-01-2014.pdf

3277-CHENP-2008 FORM-1 15-09-2014.pdf

3277-CHENP-2008 FORM-3 15-09-2014.pdf

3277-CHENP-2008 EXAMINATION REPORT REPLY RECIEVED 15-09-2014.pdf

3277-CHENP-2008 POWER OF ATTORNEY 29-01-2014.pdf

3277-chenp-2008 abstract.pdf

3277-chenp-2008 claims.pdf

3277-chenp-2008 correspondence-others.pdf

3277-chenp-2008 description (complete).pdf

3277-chenp-2008 drawings.pdf

3277-chenp-2008 form-1.pdf

3277-chenp-2008 form-3.pdf

3277-chenp-2008 form-5.pdf

3277-chenp-2008 pct.pdf

3277-CHENP-2008-Petition for Filing particulars.pdf

3277-CHENP-2008-Petition for VET Certificate.pdf