JPH11217443A - Horizontal reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive horizontal reactor with little generation of foreign materials which remarkably improves the reaction rate and the quality of a polyester manufactured therewith. SOLUTION: This reactor is equipped with a cylindrical reaction vessel (1) having an inlet (2) and an outlet (3) of the reaction liq. at or near both ends, respectively, freely rotatable end discs (8) and (9) located, facing to each other, at both ends inside the reaction vessel, a multiple no. of discs having an opening (13), located between the end discs and with the opening in the center, agitating blades (10) linking an end disc with a disc having an opening, and a disc having an opening with another disc, and located with a specific clearance to or close to the inner wall surface (7) of the reaction vessel, and free surface forming parts (11) and (12) placed in a single or multiple rows at locations where they can contact at least part of the reaction liq. falling along the falling edges of the agitating blades where the reaction liq. goes to fall from the agitating blades, and in approximately parallel with the falling edges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal reaction vessel used for synthesizing a condensable high molecular compound such as polyester, polyamide, and polycarbonate which produces a volatile low molecular substance by reaction.

[0002]

2. Description of the Related Art High molecular compounds such as polyesters, polyamides and polycarbonates, among which polyesters represented by polyethylene terephthalate and polybutylene terephthalate, have excellent physical and chemical properties and are widely used for various purposes. I have. In particular, polyester is excellent in mechanical properties such as strength and elastic modulus, heat resistance and the like, and is therefore widely used as industrial fibers such as clothing and tire cords, or as films and engineering plastics.

In general, as a method for producing a polyester used for such various uses, a direct polymerization method or a transesterification method is used.

In the former direct polymerization method, a polyester precursor is formed by directly esterifying an acid component and a diol component, and then the polyester precursor is polycondensed under reduced pressure to produce a polyester. How to On the other hand, the latter transesterification method is a method in which a lower alkyl ester of an acid component is transesterified with a diol to form a polyester precursor, and then the polyester precursor is polycondensed under reduced pressure.

In the past, in the polymerization of polyesters, a batch system has been used in many cases. However, in recent years, a switch to a continuous system has been promoted in order to take advantage of scale and to produce polyester at low cost. Is coming. This is because the use of the continuous method has extremely large advantages such as a decrease in yield, an improvement in quality, a uniform polymerization degree, and an improvement in operability.

In general, many of the production methods of continuous polymerization of polyester are carried out by a process in which a plurality of transesterification or esterification reaction tanks and a polycondensation reaction tank are combined. For example, a raw material is supplied to a transesterification reaction tank or an esterification reaction tank to generate a monomer, and the obtained monomer is supplied to an initial polycondensation reaction tank and reacted under reduced pressure to produce a low polymer. Is produced and supplied to a polycondensation reaction tank to produce an intermediate polymer and a high polymer under reduced pressure.

[0007] In such a polycondensation reaction tank, many methods for obtaining a higher reaction rate have been proposed and put into practical use. For example, as one of such conventional methods, in a polycondensation reaction of a polyester, a thin film reaction tank in which a reaction product is made into a thin layer for the purpose of quickly separating and removing by-products such as glycols is performed. It has been practiced to use a reaction tank that can facilitate the evaporation of the by-products by increasing the evaporation area of the reactants by using or stirring vigorously.

Here, as the above-mentioned reaction tank, a vertical reaction tank of a wet wall type or a screw type, and a horizontal reaction tank of a single-axis or twin-axis type are generally used. Furthermore, there are many commercially available reaction tanks that take into account stirring so that the free surface area of the reactants can be increased.However, in these reaction tanks, strong stirring is required. Therefore, there is a problem that the equipment cost is high and a lot of energy is consumed. In addition, due to the reaction caused by the intense stirring, the obtained reactant tends to cause unevenness in the degree of polymerization and the like, and has a problem that the quality of the obtained polyester deteriorates. Furthermore, there is a problem that the quality of the reaction product is also deteriorated by mixing the deteriorated polymer as a foreign substance due to insufficient renewal of the polymer or the like staying in the gas phase for a long time. In the present invention, the `` horizontal reaction tank '' refers to a `` reaction tank provided such that the center axis direction of the rotation axis of the stirring blade provided in the reaction tank is substantially parallel to the horizontal plane ''. I do.

In order to solve such a problem, a horizontal reaction tank as proposed in Japanese Patent Publication No. 40-3964 is used to agitate the reaction solution by stirring, and then to remove the reaction solution. It has been practiced that a large part of the liquid is dropped to constantly form a liquid film of a new reactant, and the reaction is performed in an extremely short time. In this horizontal reaction tank, stirring shafts for holding stirring blades are provided only at both ends of the tank, thereby adopting a structure in which the stirring shaft is eliminated from an intermediate portion inside the reaction tank. Further, the reaction vessel includes (1) the stirring blade which opposes most of the inner peripheral wall surfaces of the reaction vessel with a small gap therebetween, and (2) integrally rotates with the stirring blade and two or more blades. And a partition plate having an opening at the center thereof for partitioning the inside of the reaction tank.

Certainly, according to the reaction vessel, the inner peripheral wall surface of the reaction vessel is constantly renewed with a new reaction solution, so that the heat transfer to the reaction solution is good, and the reaction solution is used for a long time. The advantage is that it does not adhere to the inner peripheral wall surface and that there is no stirrer shaft in the middle part of the reaction tank, so that a situation in which a cluster of reactant masses is formed around the stirrer shaft does not occur. have.

However, in the reaction tank, no consideration is given to the form of the liquid film of the reactant falling from the stirring blade, and there is no contrivance in controlling the free surface of the falling liquid film. Not done. For this reason, in the reaction tank, the ability to form such a free surface of the liquid film is limited, and it is extremely difficult to further increase the reaction efficiency.

[0012]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, an object of the present invention is to eliminate the need for intense agitation and to reduce the generation of foreign substances during the reaction. It is an object of the present invention to provide an inexpensive horizontal reactor capable of significantly improving the speed or reaction efficiency and the quality of the produced polyester.

[0013]

As means for solving the above-mentioned problems, "(A) a cylindrical reaction tank having a reaction liquid inlet and outlet at or near both ends thereof, respectively, (B) A rotatable end disc provided opposite to both ends inside the reaction vessel, (C) an open disc disposed between the end discs and having an opening in the center thereof;
(D) It is installed between the end disk and the opening disk, and between the opening disks, and a predetermined gap or close contact is made with the inner peripheral wall surface of the reaction tank along the longitudinal direction of the reaction tank. (E) Along the falling edge of the stirring blade at which the reaction liquid starts to fall from the stirring blade, the stirring blade is positioned substantially at a position where it can come into contact with at least a part of the falling reaction liquid. In parallel, there is provided a "horizontal reaction vessel having free surface forming members provided in multiple rows or single rows."

[0014]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG.
It is a side sectional view which illustrated the horizontal type reaction vessel for carrying out the present invention.

In FIG. 1, reference numeral 1 denotes a horizontal reaction tank main body, reference numeral 2 denotes a reaction liquid inlet, and reference numeral 3 denotes a reaction liquid outlet, which are provided at both ends or near both ends of the reaction tank 1 as shown. . Reference numerals 4 and 5 denote shafts provided at both ends of the reaction tank 1. Reference numeral 6 denotes a steam outlet, which is opened above the outer shell of the reaction tank, and also serves as a suction port for keeping the inside of the reaction tank at reduced pressure.
Reference numeral 7 denotes an inner peripheral wall surface of the reaction tank 1. If necessary, a projection can be provided on the inner peripheral wall surface 7 so as not to interfere with the stirring blade 10. Reference numerals 8 and 9 denote end discs, which are fixed to the shafts 4 and 5. The end discs 8 and 9 can be rotated by driving the shafts 4 and 5 with the power of a driving device (not shown). 10 is a stirring blade provided near or closely in the longitudinal direction of the inner peripheral wall surface 7, 11 and 12 are:
Round bars having different diameters are illustrated in the embodiment of FIG. 1 as free surface forming members arranged in two rows in parallel with the falling edge of the reactant of the stirring blade 10. Reference numeral 13 denotes an open disk, which is provided with the stirring blade 10 and the round bars 11 and 1.
2 and is connected and fixed at predetermined intervals in the longitudinal direction, has an opening at the center thereof, and further has a role of dividing the inside of the reaction tank 1 into a plurality of chambers.

The round bars 11 and 12, which are the free surface forming members, come into contact with at least a part of the falling reaction solution along the falling edge of the stirring blade where the reaction solution starts to fall from the stirring blade 10. It is provided in a double row or a single row at a possible position substantially parallel to the falling edge. In addition, the opening disk 13 which rotates together with the stirring blade and the round bar allows the reaction tank 1 to be rotated.
Is partitioned into two or more chambers in the longitudinal direction.

Here, the stirring blade 10 rotates and the reaction tank 1 is rotated.
The stirring blade 10 is inclined so that the edge on the side close to or close to the inner peripheral wall surface 7 faces downward while the inside gas phase portion is rising, and the falling edge on the opposite side faces upward. And
While descending the gas phase portion in the reaction tank 1, the stirring blade 10 may be inclined such that the edge on the side close to or close to the inner peripheral wall surface 7 faces upward, and the falling edge on the opposite side faces downward. preferable. In this manner, the reaction liquid is scooped up along the inner peripheral wall 7 while the stirring blade 10 is moving up the gas phase in the reaction vessel, and the reaction liquid is thinned on the stirring blade 10 while the stirring blade 10 is moving down. The reaction liquid flowing down from the stirring blade 10 can be brought into contact with the free surface forming member. In the case where the stirring blade 10 is brought into close contact with the inner peripheral wall surface 7, a tail fin may be additionally provided.
The tail can also promote the renewal of the reaction solution attached to the inner peripheral wall surface 7.

FIG. 2 is a front view of the opening disk 13. In the drawing, reference numeral 10 denotes plate-shaped stirring blades inclined in the direction opposite to the rotation direction, and four blades are arranged at 90 ° in the circumferential direction of the reaction tank 1. On an extension of each stirring blade 10, round bars 11 and 12 are arranged in two rows substantially parallel to each other along the falling edge of the reaction liquid of the stirring blade 10 as a free surface forming member. At this time, it is preferable that the diameter of the round bar 12 arranged closest to the rotation center of the stirring blade is larger than the diameter of the round bar 11 arranged farther from the rotation center. In addition, whether the diameter of the round bars 11 and 12 is equal,
On the other hand, when the diameter of the round bar 11 is larger than the diameter of the round bar 12, it is difficult to form a liquid flow of the reactant as a multilayer film. This is because, in such a case, most of the reaction liquid often droops from the gap between the stirring blade 10 and the round bar 11 in a united manner, so that a desired stable multi-layer film is formed. This is because it is difficult to sufficiently form a liquid flow having many free surfaces.

As described above, in the present invention, the reaction liquid dripping from the stirring blade is further brought into contact with the free surface forming member, and the multi-layer liquid film or the free surface becomes as large as possible from the stirring blade or the free surface forming member. One of the major features is that it is made to flow down. Instead of a round bar, a bar having a cross section of a polygon, an oval, an ellipse, or the like can be used, and a plate such as a flat plate or a curved plate can be used. Can be made into a lattice shape or a net shape, or a perforated plate. Even in such a case, it is needless to say that it is preferable that the conditions are such that many free surfaces are formed when the reaction solution flows down. Therefore, it is needless to say that a free surface forming member is used so that the free surface is not reduced when the liquid flows down.

Here, conditions such as the number, shape, and size of the stirring blades and the free surface forming member, and the intervals at which the stirring blades and free surface forming members are installed differ depending on manufacturing conditions and the like. However, under these conditions, it is important that the falling reaction liquid is brought into contact with the free surface forming member to flow down while forming a liquid flow having a large free surface area such as a multilayer film. Further, since the melt viscosity of the reaction solution changes from the inlet to the outlet of the reaction tank, it goes without saying that these can be changed accordingly.

The present horizontal reaction tank has a heating means (not shown) for heating to a desired temperature. As shown in Fig. 1, a double jacket structure is used, and a heating method is used in the presence of a suitable heating medium, for example, a heating medium liquid such as Dowsome or a heating medium vapor, and a method of installing a heat transfer surface in a reaction chamber. Etc. can be appropriately adopted. The heating may be performed so that each reaction chamber divided by an open disk and / or the reaction chamber is further divided so that heating can be performed independently for each divided region, or two or more reaction chambers are integrated. It can also be heated as. further,
If necessary, a circulating means having a heat exchanger provided inside the horizontal reaction vessel of the present invention or separately may be provided. The reaction pressure is not limited to reduced pressure, and it is needless to say that the reaction can be performed under an inert gas atmosphere at normal pressure or a pressure higher than normal pressure. Can be.

Next, an experimental example in the case of producing polyethylene terephthalate using the horizontal reaction vessel of the present invention will be described.
In the experimental examples, “intrinsic viscosity” is a value obtained from a viscosity measured at 35 ° C. using orthochlorophenol as a solvent, and “%” is% by weight.

Antimony trioxide 0.04 as a polymerization catalyst
% Of a polyethylene terephthalate intermediate polymer having an intrinsic viscosity of 0.3 at a rate of 43 kg / hr was supplied from the inlet 2 of the reaction vessel in FIG. The reaction was heated from 280 ° C. at the inlet to 285 ° C. at the outlet by heating from a jacket enclosing the heating medium.
Controlled to heat to ° C. The reaction pressure was maintained at a vacuum of 1.5 mmHg by sucking the gas inside using an ejector (not shown). The number of rotations of the shafts 4 and 5 is controlled by a motor so as to be a constant rotation of 5 rpm, and the end disks 8 and 9 are rotated, and the stirring blades 10 connected and fixed to the end disks 8 and 9 are controlled. The round bars 11 and 12 and the opening disk 13 were rotated. The supplied intermediate polymer was scraped up by the stirring blade, and was dropped while forming a stable two-layer liquid film from the stirring blade and the round bar. In addition, a part was rotated with the stirring blade to constantly renew the inner surface of the outer shell with a new polymer. This stirring promotes the volatilization of ethylene glycol, and promotes the polycondensation reaction.
It flows into the next chamber mainly due to overflow from the central opening of the opening disk 13 constituting the cutting plate, and after a residence time of about 1 hour, a polyethylene terephthalate high polymer having an intrinsic viscosity of 0.66 from the outlet 3 after the residence time. was gotten. Further, the inner peripheral wall surface 7 of the reaction tank is constantly renewed with a new polymer due to the scraping effect of the stirring blade, so that polyethylene terephthalate with less foreign matter is used.
It was 4 times faster.

[0024]

According to the present invention described above, there is provided an inexpensive horizontal reaction vessel capable of significantly improving the reaction rate and the quality of the reaction product and having little generation of foreign substances. In addition, the reaction liquid having a simple structure can form a liquid flow having a large free surface area, such as a stable multi-layer film, for the reaction liquid falling from the agitating blade, whereby the effect of significantly increasing the reaction speed can be obtained. For this reason, there is an effect that the size of the reaction layer can be made compact. Therefore, by using the horizontal reaction tank of the present invention, a high molecular compound with less generation of foreign substances can be synthesized, and it is extremely useful as a fiber, a film or other molding materials.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view illustrating a horizontal reaction tank for carrying out the present invention.

FIG. 2 shows a front view of the opening disk 13;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer shell of horizontal reaction tank 2 Reaction liquid inlet 3 Reaction liquid outlet 6 Steam outlet 7 Inner peripheral wall surface of reaction tank 8, 9 End disk 10 Stirrer blade 11 Free surface forming member (small diameter round bar) 12 Free surface forming member (Large-diameter round bar) 13 Open disk

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[Procedure amendment]

[Submission date] November 4, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Here, the stirring blade 10 rotates and the reaction tank 1 is rotated.
The stirring blade 10 is inclined such that the edge on the side close to or close to the inner peripheral wall surface 7 faces downward while the inside gas phase portion is rising, and the falling edge on the opposite side faces upward. Then, while descending the gas phase portion in the reaction tank 1, the stirring blade 10 is inclined such that the edge on the side close to or close to the inner peripheral wall surface 7 faces upward, and the falling edge on the opposite side faces downward. Is preferred. By doing so, the reaction liquid is scraped up along the inner peripheral wall surface 7 while the stirring blade 10 is moving up the gas phase portion in the reaction tank, and is moved upward when the stirring blade 10 is moving down. Can flow down in a thin film state of the reaction solution, and further, the reaction solution flowing down from the stirring blade 10 can be brought into contact with the free surface forming member. In the case where the stirring blade 10 is brought into close contact with the inner peripheral wall surface 7, a tail fin may be additionally provided.
The tail can also promote the renewal of the reaction solution attached to the inner peripheral wall surface 7.

Claims (4)

[Claims] 1. A horizontal reaction vessel comprising the following components (A) to (E). (A) A cylindrical reaction tank having an inlet and an outlet for a reaction solution at both ends or near both ends thereof. (B) A rotatable end disk provided opposite to both ends inside the reaction tank. (C) an open disk disposed between the end disks and having an opening in the center thereof. (D) A stirring blade provided between the end disk and the opening disk, and between the opening disks, and provided close to or close to the inner peripheral wall surface of the reaction tank along the longitudinal direction of the reaction tank. . (E) Along the falling edge of the stirring blade where the reaction liquid starts to fall from the stirring blade, at a position where it can come into contact with at least a part of the falling reaction liquid, substantially in parallel with the falling edge, in a double row or A free surface forming member provided in a single row. 2. The free surface forming member according to claim 1, wherein
2. The horizontal reaction tank according to claim 1, wherein the horizontal reaction tank is a rod-shaped body provided in a row. 3. The rod-shaped body is a round bar, and a diameter of a round bar disposed at least at a position closest to a rotation center of the stirring blade is smaller than a diameter of a round bar adjacent to the round bar. The horizontal reaction vessel according to claim 2. 4. The rotating edge of the gas phase portion in the reaction tank is rotated downward, the edge on the side close to or close to the inner peripheral wall 7 faces downward, the falling edge on the opposite side faces upward, and An agitating blade is tilted such that an edge on a side close to or close to the inner peripheral wall surface faces upward while a rotating edge of the inside gas phase portion is downward, and a falling edge on the opposite side faces downward. The horizontal reaction vessel according to any one of claims 1 to 3.