JPH04335001A - Multistage stirring type polymerization reactor - Google Patents

Abstract

PURPOSE:To improve piston-flowability of liquid and enhance the efficiency of heat removal or heating. CONSTITUTION:The title reactor comprises a vertical cylindrical tank 4, a rotating shaft 5 arranged along the axis of the tank 4, a plurality of stirring blades 6 arranged apart from one another on the shaft 5, and cylindrical heat conductors 7 each arranged between blades 6,6 so as to surround the shaft 5 and having a passageway for a heating medium 10.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a multistage stirring type polymerization reaction apparatus for continuously producing high molecular weight polymers, and more specifically, it is mainly used for homogeneous phase solution polymerization and bulk polymerization to increase viscosity. The present invention relates to a continuous type, multi-stage stirring type polymerization reaction apparatus.

0002

BACKGROUND OF THE INVENTION Conventionally, solution polymerization and bulk polymerization have been widely used as polymerization methods for producing polymers. In a solution polymerization method or a bulk polymerization method, if the polymer is a monomer or is dissolved in a solvent, the polymer becomes a homogeneous liquid phase system, and the viscosity increases significantly as the polymerization reaction progresses.

[0003] Polymerization reactions that take the form described above include bulk polymerization of polymethyl methacrylate, solution and bulk polymerization of acrylonitrile/styrene resin, solution polymerization of acrylonitrile/butadiene/styrene resin, solution polymerization of polybutadiene, and styrene/butadiene resin. solution polymerization of rubber,
Polycondensation of nylon 6 using ε-caprolactam as raw material (
(especially in the final stage), polycondensation of nylon 66 using adipic acid and hexamethylene diamine as raw materials (especially in the intermediate stage)
, solution polymerization of polyvinyl acetate, etc.

[0004] Generally, in polymers with high viscosity, it is difficult to remove the heat generated by the polymerization reaction, and abnormal retention areas are likely to occur in the polymerization system, resulting in uneven temperature and concentration distribution, and This results in a decrease in the quality of merging.

[0005] Therefore, as a continuous polymerization reaction apparatus for highly viscous fluid, an apparatus which has a high piston flow property without stagnation and which can uniformly remove the reaction heat has been desired, and various conventional reaction apparatuses have been proposed. ing.

Conventionally proposed continuous polymerization reactors include devices in which a plurality of heat exchange tubes and stirring blades are combined in multiple stages (US Pat. Nos. 2,727, 884).
No.), a device in which a baffle plate and a multi-tubular heat exchanger are provided between a plurality of helical ribbon blades and each stirring blade (Japanese Patent Laid-Open No. 53-992
90, JP-A-58-122901), etc.

[0007]

[Problems to be Solved by the Invention] In the conventional continuous polymerization reaction apparatus described above, the former has a limited heat transfer area because a plurality of tubes arranged in parallel are directly attached to a container. In addition, if the stirring is insufficient, there is a problem in that a lattice-like drift or abnormal stagnation tends to occur in the flow direction of the polymer. On the other hand, the latter still has problems such as uneven flow between the tubes of the multi-tubular heat exchanger, blockage of the tubes by high viscosity fluid, and a decrease in the heat transfer coefficient.

The present invention solves the various problems of the conventional continuous polymerization reaction apparatus, namely, a high piston flow property of the liquid to be treated, which is desired in solution polymerization and bulk polymerization reactions.
It is an object of the present invention to provide a multi-stage stirring type polymerization reaction apparatus having excellent heat removal performance.

[0009]

[Means for Solving the Problems] The multistage stirring type polymerization reaction apparatus of the present invention comprises a vertical cylindrical container having a liquid inlet and a liquid outlet, and a rotating shaft arranged in the axial direction of the container at the center of the container. ，
and a plurality of stages of stirring blades attached to the same rotating shaft and arranged at intervals from each other, and a heating medium passage arranged between the stages of stirring blades, and arranged around the rotating shaft. It is characterized by having a cylindrical heat transfer body.

0010

[Operation] The cylindrical heat transfer body disposed between adjacent stirring blades surrounding the rotating shaft prevents a short path of liquid and an axial back-mixing flow caused by the stirring blades. Also,
The heat transfer body surrounding the rotating shaft has a cylindrical shape, which prevents abnormal retention and drift of the liquid passing through it, and ensures high piston flow performance as a whole of the device.

Furthermore, in the present invention, the heat transfer area can be increased by increasing the number and axial length of the cylindrical heat transfer bodies.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained with reference to FIGS. 1 to 3. In FIG. 1, a rotating shaft 5 is inserted coaxially with the container 4 into a vertical cylindrical container 4 having a liquid inlet 1 at the top, a liquid outlet 2 at the bottom, and a jacket 3 around the sides. The stirring blades 6 attached to the rotating shaft 5 are installed in multiple stages at predetermined intervals in the axial direction of the rotating shaft 5, and the stirring blades 6 are attached to the rotating shaft 5 as shown in FIGS. The adjacent stages are offset by 90° from each other.

As shown in FIG. 2, between the adjacent stirring blades 6 and 6 in the container 4, a plurality of cylindrical heat transfer bodies 7 are arranged in multiple stages concentrically with the rotating shaft 5 and arranged inside and outside. be done. The heat transfer body 7 has a double structure so that the heat medium 10 flows,
It is connected to the jacket 3 via a connecting pipe 11. Further, the heat transfer body 7 is fixed within the container 4 by a heat transfer body support 11.

The width b of the heat transfer body 7 and the flow path interval P between the heat transfer bodies 7 through which the liquid passes are the heat transfer area necessary for heat removal, and the heat transfer body 7
It is set in consideration of the pressure loss and flow rate distribution of the liquid passing between the two. That is, the heat transfer area can be increased by reducing the width b of the heat transfer body 7 and the channel interval P. Furthermore, by changing the interval P between each flow path of the heat transfer body 7 for each flow path, uneven flow of the liquid passing between the heat transfer bodies 7 can be prevented. When the inner diameter of the container is 1000 mm or more, the axial length of each stage of the heat transfer body 7 is 50 to 50 mm of the inner diameter of the container.
A range of 100% is desirable.

The number of stirring blades 6 per stage is one or more, and the shape thereof can be a flat paddle, an inclined paddle, a helical ribbon blade, etc. It is desirable that the circulation flow in the axial direction is small compared to the flow. The height of the stirring blade 6 is in the range of 50 to 100% of the axial length of the heat transfer body 7, and the clearance between the container 4 and the tip of the stirring blade 6 is 10% of the inner diameter of the container 4.
Hereinafter, it is particularly desirable to keep the content to 5% or less. It is also preferable that the clearance between the stirring blade 6 and the heat transfer bodies 7, 8 be equivalent to the clearance with the container 4.

In this embodiment configured as described above, the liquid 9 to be treated flows downward in the axial direction of the rotating shaft 5 inside the cylindrical container 4 from the liquid inlet 1 to the liquid outlet 2. Stirring blade 6
A cross-sectional flow is formed in the liquid by the rotation of , and the temperature and concentration of the liquid are made uniform by stirring and mixing in a cross section perpendicular to the rotating shaft 5, that is, in the horizontal direction.

As the agitating blades 6 rotate, a vertical flow of the liquid occurs.
Since the heat transfer body 7 is disposed concentrically with the piston, its partitioning effect suppresses short passes, back mixing, etc. of the liquid 9 between the adjacent stirring blades 6, and high piston flow properties are obtained. The heat transfer body 7 has a simple cylindrical structure, so that abnormal retention of the liquid 9 is unlikely to occur, and by setting the flow path intervals to predetermined intervals, it is possible to suppress the uneven flow of the liquid 9. In addition, by flowing the heat medium 10 through the heat transfer body 7, the reaction liquid 9 passing through the heat transfer body can be uniformly cooled and heated, so that the temperature and concentration unevenness of the reaction liquid at the exit of the heat transfer body 7 is small, and therefore, The required stirring power is relatively low.

In this embodiment, a plurality of stages of cylindrical heat transfer bodies arranged inside and outside concentrically with a plurality of rotating shafts are used, but each stage may have one heat transfer body. As for its shape, a cylindrical shape other than a cylinder, such as a spiral plate concentric with the rotation axis, can be used. Further, in this embodiment, the liquid inlet is provided at the top of the container and the liquid outlet is provided at the bottom of the container, but the positions may be reversed.

[0019]

[Effects of the Invention] According to the present invention, by arranging a plurality of cylindrical heat transfer bodies concentrically with the rotating shaft between adjacent stirring blades,
It is possible to provide a multi-stage stirring type polymerization reaction apparatus which can impart high piston flow properties to the liquid to be treated, can uniformly heat or remove heat from the liquid, and is useful for solution polymerization and bulk polymerization reactions.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1;

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1;

[Explanation of symbols]

1 Liquid inlet 2 Liquid outlet 3 Jacket 4 Container 5 Rotation axis 6 Stirring blade 7 Heat transfer body 9 Liquid 10 Heat medium 11 Heat transfer element support

Claims (1)

[Claims] Claim 1: A vertical cylindrical container having a liquid inlet and a liquid outlet, a rotating shaft disposed at the center of the container in the axial direction of the container, and a rotating shaft attached to the rotating shaft and spaced apart from each other. a cylindrical heat transfer body disposed between the stages of stirring blades, having a heat medium passage and surrounding the rotating shaft; A multi-stage stirring polymerization reactor.