JPS62186929A - Reaction vessel - Google Patents

Abstract

PURPOSE:To quickly perform uniform dispersion of a low-viscosity liquid in a medium-viscosity liquid by providing both stirring blades consisting of the double helical ribbon blade having the specified shape and baffles arranged in the space parts wherein the stirring blades are cut and removed to the inside of a vessel. CONSTITUTION:A rotating shaft 3 is provided parallel to the lengthwise direction of a reaction vessel main body 1 and the stirring blades 4 are provided to the tips of the supporting rods which are taken out in the vertical direction for the shaft center of the rotating shaft 3. The stirring blades 4 having such a shape that 25-75% double helical ribbon blade is symmetrically cut and removed and bent to the inside of the vessel. The definite distance is kept between the stirring blades 4 and the wall surface of the reaction vessel. The baffles 6 are provided to the tips of the supporting rods which are vertically fixed on the wall surface of the main body 1 and extended therefrom, and a plate shape is preferable as the shape thereof. In the reaction vessel having such a constitution, a low-viscosity liquid can be uniformly dispersed in a medium-viscosity liquid efficiently for a short time.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to a reaction vessel, more specifically a medium viscosity (10p
The present invention relates to an improvement of a reactor that handles a reaction solution of about 200 poise (poise to 200 poise).

The reactor of unreleased IJJ is especially suitable for medium viscosity reaction liquids and low viscosity (
It is suitable as a reaction vessel when it is necessary to add 0.1 cp to several cp of a reaction reagent to uniformly disperse one reaction reagent and allow the reaction to proceed.

[Prior Art 1] Conventionally, there is a polymerization reaction or a copolymerization reaction as a reaction in which a reaction liquid of medium viscosity (about 10 poise to 200 poise) is handled. In such a reaction, it is often necessary to add a reaction reagent of low viscosity (0.1 cp to several cp) to a medium viscosity reaction solution to uniformly disperse one reaction reagent to allow the reaction to proceed.

A copolymerization reaction of styrene and maleic anhydride will be described as an example of a reaction that handles such a medium-viscosity reaction liquid.

The radical copolymerization reaction of styrene and maleic anhydride tends to produce alternating copolymers.1 For example, in order to obtain a copolymer with a uniform composition with a maleic anhydride content of 40 wt%, the reactivity ratio rl+r2 requires seven polymers. When the composition ratio is calculated, the weight ratio is 1 part maleic anhydride to 9 parts styrene, which shows that it is necessary to proceed with the polymerization reaction while maintaining a 7-mer composition in which the proportion of maleic anhydride is very small. That is, it is necessary to use a reaction method in which maleic anhydride is added successively as the polymerization reaction progresses.

For the copolymerization reaction of styrene and maleic anhydride, a solution polymerization method is generally employed in which the copolymerization reaction is carried out in an organic solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, or benzene.

This is because maleic anhydride reacts with water, making it difficult to perform suspension polymerization or emulsion polymerization in an aqueous solvent, and in bulk polymerization, the reaction solution becomes extremely viscous, making it difficult to handle. The main reason is that it becomes difficult to remove generated heat such as reaction heat due to the decrease in .

In the copolymerization reaction of styrene and maleic anhydride in an organic solvent, the viscosity of the reaction solution changes from about 1 cp to 20 cp as the reaction progresses.
It varies up to about 000 cp. As mentioned above, in order to obtain a copolymer with a uniform composition and excellent physical properties, maleic anhydride (generally an organic solvent solution in which maleic anhydride is dissolved:
It is necessary to advance the reaction by sequentially adding viscosity number cp) to the reaction liquid, but at this time, maleic anhydride needs to be uniformly dispersed in the reaction liquid in a sufficiently short time compared to the reaction rate.

Conventionally, when carrying out the above reaction, a vertical reaction vessel with a paddle shield was used, or a double helical ribbon blade was used instead of a large paddle.

[Problems to be Solved by the Invention] However, when the above reaction is carried out in a reactor equipped with a paddle blade in a vertical reactor, maleic anhydride is not uniformly dispersed and a copolymer with a wide composition distribution is produced. Moreover, the alternating copolymer precipitates from the solvent and adheres to the wall of one reaction vessel in large quantities, which is an undesirable result.

In addition, if the reaction is carried out using a large double helical ribbon instead of a paddle blade, a co-rotating phenomenon will occur between the reaction solution and the double helical ribbon blade, and maleic anhydride will be uniformly dispersed, similar to when using a paddle blade. Instead, only a copolymer with a wide composition distribution is obtained, and a large amount of polymer is attached to the wall of a can. Furthermore, the heat transfer coefficient becomes extremely small and the heat removal ability deteriorates.

Generally, paddle blades, turbine χ, etc. are used to stir low viscosity liquids.
Anchor blades, screw blades, helical ribbon blades, etc. are used to stir high viscosity liquids, but when the reaction is performed with these ready-made stirring blades.

The above-mentioned disadvantages occur and it is impossible to obtain a preferred copolymer of styrene and maleic anhydride.

[Means for Solving the Problems] The present invention has been made in view of the above points, and it eliminates the above-mentioned drawbacks of the prior art and achieves sufficient uniform dispersion of low-viscosity liquids in medium-viscosity liquids. The present invention provides a reaction vessel that allows the reaction to be carried out quickly.

That is, according to the present invention, there is provided a reaction can in which a stirring blade and a baffle are installed in one can, and the stirring blade has double helical ribbon blades with 25% to 75% cut symmetrically and curved toward the inside of the can. Provided is a reaction vessel, characterized in that the stirring blade and the wall surface of the reaction vessel have a certain distance, and the baffle is disposed in a space where the stirring blade is cut and removed. be done.

[Example] The present invention will now be described in more detail with reference to an example shown in the drawings. Figures 1 to 3 show an example of a reaction vessel according to the present invention. Figure 1 is a longitudinal cross-sectional view of the reaction vessel, Figure 2 is a cross-sectional view, and
The figure is a diagram showing the relative positions of stirring blades and baffles.

1 is a heating (heat removal) device 2 (generally hot water) on the outer periphery.

Reaction vessel body equipped with jacket heating or dematuring W1) using a heat medium such as steam or oil; 3 is a rotating shaft; 4
is a stirring blade, 5 is an auxiliary stirring blade, and 6 is a baffle. or,
L/D=b/a of reaction vessel 1 is in the range of 1.5 to 2.

As shown in Figures 1 and 2.

The rotation axis 3 is provided parallel to the longitudinal direction of the reaction can body l,
A stirring blade 4 is installed at the tip of a support rod taken out from the rotating shaft 3 in a direction perpendicular to the axis. The stirring blade 4 has a shape in which 25% to 75% of the double helical ribbon blade is symmetrically cut off and curved toward the inside of the can. Further, Wl, the stirring blade 4 and the wall surface of the reaction vessel are kept at a constant distance. This distance d is preferably 20 mm or less, preferably 15 layers or less, regardless of the volume of the reaction vessel. By doing so, it is possible to further reduce the retention of the reaction liquid near the wall surface of the reaction vessel. Stirring y It is preferable that C is in the range of 1120 to 1/10 of the inner diameter a.

The length of the stirring blade 4 is determined by the inclination angle θ1 and the thickness of the rod supporting the baffle, but it is better to make it as long as possible within the construction range.
% to 75% is the symmetrically cut length.

The angle of inclination 01 is normally set at 15° for double helical blades, but in the stirring blade of the present invention, it is preferably in the range of 25° to 35″ in order to achieve good vertical stirring.

The auxiliary stirring blade 5 is necessary when the amount of reaction liquid at the initial stage of the reaction is small and the lowest stirring blade 4 does not come into contact with the reaction liquid surface. As the auxiliary stirring blade 5, a paddle blade, a retreating blade, an anchor blade, etc. may be installed, and in order to improve vertical stirring, it is preferable to tilt or twist the blade.

The number of stirring blades is preferably determined by setting the distance between stirring χ to 1/4 to 115 with respect to the length b of the straight body of the reaction vessel, and also by setting the distance between the stirring blades to 1/4 to 115 of the length b of the straight body of the reaction vessel. The distance from the tip of the upper stirring blade is preferably h or less. Therefore, it is preferable to leave a space above one reaction can so that it can be filled with the reaction liquid up to a distance h or more from the tip of the stirring blade.

The puff fluro is installed at the tip of a support rod that is fixed and extended perpendicularly to the wall surface of the main body of the reaction can, and its shape is preferably a plate.
The length g is preferably in the range of 13, and the length g is limited by the distance #h between the stirring χ, but it is approximately 1/6 of the length b of the straight body of the reaction can.
The charging length e (distance from the center of the baffle to the inner wall of the reaction can) of the baffle b, which is preferably front and back, is the length e (distance # from the center of the baffle to the center of the reaction can), and the width C of the stirring blade 4 Although it is limited by the inner diameter a of one reaction vessel, it is good to have the inner diameter a around 173. In Fig. 2, of the total six baffles 6, the two upper baffles are set at O'', the two in the middle are at the 180° position. 4
0°, 220° position, bottom two pieces at 0°.

An example is shown in which it is installed at a 180° position, but for example,
The upper two images and the lower two images are at θ° and 180°, and the middle two images are at 90° and 270°, or all are at 0°.

They may be positioned at 180°, or they may be installed in three baffles on each stage for a total of nine baffles, or in four stages.There is no particular restriction on the number of baffles, but considering the strength of one reaction vessel and the jacket area. In FIG. 3, the baffles 6 are installed parallel to the rotating shaft 3, but the inclination angle θ2 of the baffles is preferably in the range of 45° to 90°.

Although the present invention has been explained by taking an example of a copolymerization reactor of styrene and maleic anhydride, the present invention is not limited thereto, and can be applied even when uniform mixing of a medium viscosity liquid and a low viscosity liquid is a problem. Applicable if applicable. Moreover, it can be applied not only as a batch reactor but also as one of continuous reactors.

[Function] Since the present invention is configured as described above, for example, when a copolymerization reaction of styrene and maleic anhydride is carried out in an organic solvent, maleic anhydride can be uniformly produced in a sufficiently short time compared to the reaction rate. Can be dispersed. In other words, the feature of the present invention is that the sequential addition and supply position of maleic anhydride is installed at the position of black dot 7 in Fig. 1 (the baffle is made hollow and is used as a supply nozzle), so that the supplied maleic anhydride is immediately stirred. The maleic anhydride that was strongly cut by the blades and pushed upwards was divided by the upper baffle into a flow toward the center of the reaction vessel and an upward flow, and further flowed into the center of the reaction vessel. Maleic anhydride is mixed with the reaction liquid and moves downward along with the downward flow of the rotating shaft, while the upward flow near the can wall is further divided by the upper baffle, so that maleic anhydride is efficiently and uniformly produced in a short time. distributed.

[Effects of the Invention] Since the present invention is configured and operates as described above, the following effects can be achieved. That is, (1) a low viscosity liquid can be efficiently and uniformly dispersed in a medium viscosity liquid in a short time;

(2) A copolymer with a uniform composition can be obtained, and there is no polymer adhesion to the can wall due to non-uniform composition.

■ The reaction liquid and stirring blade do not rotate together, so the heat transfer coefficient is large and the heat removal capacity is large.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the reaction vessel of the present invention;
FIG. 2 is a cross-sectional view of the reaction vessel shown in FIG. 1. Third
The figure is a partial plan view showing the relative positions of the stirring blade and the baffle in the reaction vessel of the present invention. 1... Reaction can body, 2... Jacket. 3... Rotating shaft, 4... Stirring blade, 5... Auxiliary stirring blade, 6... Baffle.

Claims (1)

[Claims] A reaction can with stirring blades and baffles installed inside the can,
The stirring blade has a shape in which 25% to 75% of the double helical ribbon blade is cut symmetrically and curved toward the can side, the stirring blade and the wall surface of the reaction can have a certain distance, and the baffle is A reaction vessel characterized in that the reaction vessel is disposed in a space where the stirring blade is cut and removed.