JPH02265634A - Vertical agitating device - Google Patents

Abstract

PURPOSE:To increase evaporation speed by providing a rotating ribbon blade between a container inner wall and an outer wall of a draft tube. CONSTITUTION:High viscosity liquid 11 fed into a container lifts up a ring section formed with the container inner wall and a draft tube 3 by the rotation of a ribbon blade 7 and changes its direction at the upper end of the draft tube 3, and then flows down along the inner wall of the draft tube 3. As the lower section of the container is conical, the flowed down liquid is pushed up again by the ribbon blade 7 without forming dwell liquid. A space 12 is formed on the lower surface of the ribbon blade 7, and said space is of helical shape along the ribbon blade 7 and its evaporating surface is enlarged. High evaporation speed is generated by said process.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to evaporation operations for removing low-boiling point components from high viscosity liquids, evaporation of monomers or solvents during solution polymerization or bulk polymerization reactions of addition polymers. The present invention relates to a vertical stirring device used in evaporative cooling operations, etc., in which the heat of reaction is removed using the latent heat of evaporation.

[Conventional technology]

Conventionally, as a device for evaporating low-viscosity components from a high-viscosity liquid and simultaneously advancing a reaction such as a polymerization reaction, a stirring device for high-viscosity liquids having built-in helical ribbon blades or anchor blades has been frequently used.

FIG. 3 shows a conventional stirring device using helical ribbon blades.

Helical ribbon wings 23 connected to a rotating shaft 22 are provided within the container 21, and these rotate in the direction of an arrow 24 shown in the figure. The high viscosity liquid in the container 21 is pushed up by the helical ribbon blades 23 and generates an upward and downward circulating flow like the streamlines 25. Further, as a result, the liquid surface 26 becomes concave at the center as shown in the figure.

[Problem to be solved by the invention]

Problems with the above-mentioned conventional stirring device using ribbon blades include the following.

(1) The evaporation surface area is small.

Mass transfer rate Na (
s+ol/h・Omotsu) is N, −kL−a・Δc −−−−−(1)k
L: Mass transfer coefficient (W/h) a: Surface area per unit liquid volume (I11!/II) ΔC:
Difference in concentration of low molecular weight components between liquid phase and gas phase (+*ol/
s'').

As can be seen from the above equation (1), in order to increase the evaporation rate,
In other words, it is important to increase the surface area of the liquid. However, as shown in FIG. 3, the conventional device does not have a large surface area.

(2) The surface update rate is low.

The mass transfer coefficient kt in equation (1) is proportional to the speed S at which the surface of the liquid is renewed to a new surface, (18) raised to the power of l/. Basics and Analysis (see page 123), S to increase the evaporation rate,
needs to be made larger.

In the conventional device shown in FIG. 3, all of the liquid pushed up by the helical ribbon blades 23 does not flow as a whole as shown by the streamlines 25, and the flow +! 27, which short-circuits the top and bottom of the blade. Considering that in order to increase S, it is necessary to increase the overall flow rate of the streamlines 25, the conventional device is not preferable.

The present invention aims to provide a stirring device with ribbon blades that solves the above problems.

[Means to solve the problem]

The stirring device of the present invention is composed of a cylindrical container, a cylindrical draft tube provided in the container at a distance from the container, and a rotating ribbon blade installed in a gap between the inner wall of the container and the outer wall of the draft tube. be done.

[Effect]

In the present invention, the liquid rises between the inner wall of the container and the outer wall of the draft tube by the rotating ribbon blade.

The liquid pushed up by the ribbon blades ascends through the gap whose outside and inside are partitioned by the inner wall of the container and the outer wall of the draft tube, so there is no flow that short-circuits the top and bottom of the ribbon blades, and the overall flow is in the vertical direction. , a large surface update rate can be obtained.

Further, the rising liquid flow as described above rises in the annular portion between the inner wall of the container and the outer wall of the draft tube, changes direction at the upper end of the draft tube, flows down along the inner wall of the draft tube, and circulates. As a result, a liquid surface with a large area, ie, a withered surface, is formed in the container. Further, the upper surface of the rotating ribbon blade is filled with the liquid being pushed up, but a void is created in the lower surface of the ribbon blade. This gap is formed in a continuous spiral shape along the lower surface of the ribbon blade, and the upper part of the gap is connected to the gas phase inside the container, so that the evaporation surface is greatly expanded.

As described above, according to the present invention, a large surface renewal rate and a large area of evaporation surface can be covered, and evaporation can be activated.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As shown in Fig. 51, a cylindrical and a conical part of the same size as the container are combined in a container consisting of a cylindrical container 1 and a conical container 2 with a gap between them and the inner wall of the container. A tube 3 is arranged, and the upper end of the draft tube 3 is fixed to the top 1113 of the container by a plurality of round rod-shaped draft tube supports 4. A rotating shaft 5 is inserted from the bottom of the container, and a plurality of round bar-shaped wing supports 6 are connected to this, and each wing support 6 is further attached with a spiral ribbon wing 7. The ribbon wing 7 is inserted into a gap in an annular cross section formed by the inner wall of the container and the outer wall of the draft tube 3, and a clearance is maintained to the extent that it does not come into contact with the wall even when rotated.

The high viscosity liquid is supplied from the raw material supply port 8 provided in the upper lid 13 of the container, and some of its low boiling point components are evaporated within the container, and the low boiling point components are removed from the gas vent provided in the upper lid 13 of the container. The liquid is discharged from the nozzle 9, and the processed material is extracted from the liquid draining nozzle 10 at the bottom of the container.

FIG. 2 is a longitudinal cross-sectional view showing the flow state of the liquid in this example, and the left half of the figure shows a cross-section with a 90° phase shift.

The high viscosity liquid 11 supplied into the container moves up the annular part formed by the inner wall of the container and the draft tube 3 by the rotation of the ribbon blades 7, changes direction at the upper end of the draft tube 3, and
It flows down along the inner wall of the draft tube 3. Since the lower part of the container has a conical shape, the liquid that has flowed down is pushed up again by the ribbon blades 7 without creating stagnant liquid.

As shown in the figure 2. The upper surface of the ribbon wing 7 is filled with the liquid being pushed up, but a void 12 is formed on the lower surface.

This gap 12 has a spiral shape along the ribbon blade 7, and the upper part thereof is connected to the gas phase inside the container, so that the evaporation surface is greatly expanded.

In addition, since the liquid pushed up by the ribbon blades 7 is separated from the outside by the inner wall of the container and the outer wall of the draft tube 3, a flow that short-circuits the top and bottom of the ribbon blades, which occurs in the conventional device described above, does not occur. The company will be the main player in the entire upstream and downstream. Therefore, the surface renewal speed is higher than that of the conventional device.

In addition, the liquid rising in the annular portion between the inner wall of the container and the outer wall of the draft tube 3 changes direction at the upper end of the draft tube 3 and flows down along the inner wall of the draft tube 3. As shown in FIG. 2, the surface area of the liquid is expanded and the evaporation surface is expanded.

As described above, in this example, the evaporation surface is greatly expanded and the surface renewal rate is increased, so that a high evaporation rate can be obtained.

Furthermore, in this embodiment, a lower drive method is adopted for driving the ribbon blades. As mentioned above, by providing the draft tube 3, an expansion of the surface area and an increase in the surface renewal rate are achieved, but consideration must be given to the cleanability of the gap between the draft tube 3 and the container 1. , Draft tube support 4 on container top 1i13
is fixed, so by removing the top 1 [13, the draft tube 3 can be pulled out at the same time, and all surfaces inside the container can be cleaned manually.

On the other hand, in the case of top-driven agitation, the ribbon blades 7 and the draft tube support 4 collide, so the draft tube support 4 has to be fixed at the bottom. Even if the draft tube 7 is pulled out, the draft tube 3 remains fixed to the container 1 side, and the annular portion between the draft tube 3 and the container 1 remains as a portion that is extremely difficult to clean.

In the above embodiment, the container and the draft tube are made of a combination of a cylinder and a cone, but both may be cylindrical, and in this specification, the term cylindrical refers to a similar polygonal shape. It includes a cylinder.

〔Effect of the invention〕

The present invention provides the following effects by installing a rotating ribbon blade in an annular gap between a cylindrical container and a cylindrical draft tube provided at intervals within the container.

(1) The evaporation area of the liquid is expanded, and the evaporation rate is increased.

(2) The surface renewal rate of the liquid increases and the evaporation rate increases.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing the flow state of a high viscosity liquid in the same embodiment, and Fig. 3 is a longitudinal sectional view of a conventional stirring device using helical ribbon blades. It is a longitudinal cross-sectional view showing a representative example. 1... Cylindrical container, 2... Conical container, 3
... Draft tube, 4... Draft tube support, 5... Rotating shaft, 6... Wing support, 7
...Ribbon wings.

Claims (1)

[Claims] It is composed of a cylindrical container, a cylindrical draft tube provided within the container concentrically with the container, and a rotating ribbon blade installed in the gap between the inner wall of the container and the outer wall of the draft tube. Features a vertical stirring device.