JP2816158B2 - Vertical stirrer and operating method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for polymerizing a polymer produced by a bulk polymerization method, and more particularly to a method for operating a vertical stirring apparatus used in batch operation.

[Conventional technology]

As a device configuration in a conventional batch-type polymer production process, a two-can method in which two stirrers (polymerization reactors) having different stirring blades are provided in series as shown in FIG. 2 is used. In the figure, the raw material is put into a low-viscosity stirrer 13 and allowed to react for a certain period of time.
Transfer to 15

The low-viscosity stirrer 13 is operated in a range from a viscosity substantially equal to that of water to a viscosity of about several tens poise. As the reaction proceeds, the molecular weight increases, and the viscosity of the product increases accordingly. The high-viscosity stirrer 15 receives a liquid having a viscosity of several tens of poise, reacts it for a certain period of time, and discharges it as a liquid (product) of several thousand poise.

In the high-viscosity stirrer 15, helical blades and anchor blades are usually used to mix and stir the high-viscosity liquid.

Immediately after the liquid was received, the stirring blade was rotated at high speed to the full power of the motor because of the low viscosity liquid. As the reaction progressed, the viscosity increased and the power also increased. A related device of this type is, for example, Japanese Utility Model Publication No. 57-53623.

[Problems to be solved by the invention]

The above-mentioned prior art has no major consideration for equipment, cost, and stirring and mixing efficiency, and has the greatest drawback of high cost for equipment investment as an experimental equipment. Also, since only one set of stirring blades (shape) of each stirrer can be incorporated,
Mixing and stirring a liquid having a certain viscosity range takes time and has a disadvantage of low efficiency.

An object of the present invention is to provide a method of operating a vertical stirrer capable of reducing equipment cost and improving productivity by increasing mixing / stirring efficiency.

[Means for solving the problem]

The above object is achieved by providing a low-viscosity stirring blade and a high-viscosity stirring blade in one stirring tank, and controlling the rotation speed of each stirring blade according to the liquid viscosity.

In order to provide both of the above-mentioned stirring blades, the stirring shaft is provided with an inner shaft and an outer shaft concentric with the inner shaft, and two sets of driving devices are provided as a rotation control system for each shaft, and each rotation power value is detected. This is achieved by providing a rotation speed controller in each drive device.

[Action]

The baffle is obtained by rotating the low-viscosity stirring blade provided on the inner shaft at a high speed when the liquid viscosity is low, and stopping the high-viscosity stirring blade provided on the outer shaft, or rotating the stirring device at a low speed in a direction opposite to the inner shaft. The effect can be expected. Next, as the liquid viscosity changes from a low viscosity to a medium viscosity, the above blades are rotated at a medium speed. Further, as the liquid viscosity changes from a medium viscosity to a high viscosity, the low-viscosity stirring blade is rotated at a low speed, and By rotating the blades at high speed, the mixing and stirring effects can be improved, and the productivity of the product can be improved.

〔Example〕

FIG. 1 shows an embodiment of the present invention. In the figure, a low-viscosity stirring blade 2 (paddle blade) is connected to an inner shaft of a stirring tank main body 1, and a high-viscosity stirring blade 3 (helical blade) is provided so as to surround the periphery of the low-viscosity stirring blade 2 (paddle blade). , Connected to the outer shaft concentric with the inner shaft. The outer shaft is driven by the drive unit 4 and the inner shaft is driven by the drive unit 5, respectively.
Each of the stirring blades is rotated.

A system is configured in which the power required for stirring of each of the driving devices 4 and 5 is detected, and the rotation is controlled by the power indicating controller 6 on each driving train via speed controllers 7 and 8.

The raw material is introduced from the inlet nozzle 11, and the reaction proceeds by mixing and stirring, whereby the content liquid is polymerized and the liquid viscosity increases accordingly. When the mixing for a predetermined time is completed, the inside of the stirring tank body 1 is pressurized and discharged from the product outlet nozzle 10, or a gear pump (not shown) is attached to the lower portion of the stirring tank body to take out the product.

Immediately after charging the raw material, the viscosity is almost the same as that of water, so the stirring blade 2 for low viscosity is rotated at several hundred revolutions / RPM (high speed).

On the other hand, the high-viscosity stirring blade 3 is stopped or rotated at a few revolutions / RPM in a direction opposite to the low-viscosity stirring blade 2. Therefore, a baffle effect can be expected from the high-viscosity stirring blade 3, and the mixing effect is improved. As the liquid viscosity increases, the rotation speed of the low-viscosity stirring blade 2 is gradually decreased, and the rotation speed of the high-viscosity stirring blade 3 is increased. The number of rotations of 3 is made maximum. Further, when the liquid viscosity increases, the rotation speed of the high-viscosity stirring blade 3 is reduced so that the motor power does not become excessive. With a liquid viscosity of several thousand poise, the stirring tank main body 1 is required only with the stirring blade 3 for high viscosity.
Because of the poor mixing at the center, the liquid is stirred while pushing down the liquid in the direction of the arrow with the low-viscosity stirring blades 2 to promote the stirring by the high-viscosity stirring blades 3 to improve the stirring and mixing effects.

According to this embodiment, there is an effect that the liquid having a certain viscosity range from low viscosity to high viscosity can be efficiently mixed and stirred to improve the productivity. In addition, since a single set of devices can be used, there is an effect that facility costs can be significantly reduced.

〔The invention's effect〕

According to the present invention, the conventional two-can system can be processed in one can, and the equipment cost can be reduced.

Further, by providing two types of stirring blades, mixing and stirring can be improved, and there is an effect that product productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vertical stirring device according to one embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of a conventional batch type polymer production process. DESCRIPTION OF SYMBOLS 1 ... stirring tank main body, 2 ... low viscosity stirring blade, 3 ... high viscosity stirring blade, 4 ... high viscosity driving device, 5 ... low viscosity driving device, 6 ... power indicating controller , 7: Speed controller for low viscosity, 8: Speed controller for high viscosity, 13: Stirrer for low viscosity, 14: Filter, 15
…… High viscosity stirrer

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takanobu Furukawa 794, Higashi-Toyoi, Kazamatsu, Kudamatsu, Yamaguchi Prefecture Inside the Kasado Plant, Hitachi, Ltd. Engineering Co., Ltd. Kasado Office (72) Inventor Chika Oda 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. (56) References JP-A-63-111933 (JP, A) -19234 (JP, A) JP-A-59-49827 (JP, A) JP-A-62-95122 (JP, A) JP-A-48-12661 (JP, U) JP-A-4-22822 (JP, Y2) (58) Field surveyed (Int.Cl. ⁶ , DB name) B01F 7/16 C08G 85/00 C08G 69/00 C08G 63/78

Claims (2)

(57) [Claims] 1. A method of operating a vertical stirrer provided with a concentric biaxial stirring blade having an outer axis surrounding an inner axis concentric with an inner axis, wherein a low-viscosity raw material liquid is introduced into the vertical stirrer, The high-viscosity stirring blades provided on the inner shaft are rotated at a high speed, and the high-viscosity stirring blades provided on the outer shaft are stopped or rotated at a low speed in a direction opposite to the inner shaft. A method for operating a vertical stirrer, characterized in that the rotation speed of a low-viscosity stirring blade is reduced and the rotation speed of the high-viscosity stirring blade is increased to obtain a highly viscous liquid. 2. A method of operating a vertical stirrer having a concentric biaxial stirring blade having an outer shaft surrounding an inner shaft concentric with the inner shaft, the method comprising: While rotating at a high speed, the high-viscosity stirring blade provided on the outer shaft is stopped or rotated at a low speed in a direction opposite to the inner shaft, and each of the blades is rotated at a medium speed as the liquid viscosity changes from a low viscosity to a medium viscosity. And operating the vertical stirring device at a low speed and the high viscosity stirring blade at a high speed as the liquid viscosity increases from a medium viscosity to a high viscosity.