WO2024035096A1 - Reactor - Google Patents

Abstract

A reactor according to one embodiment of the present invention comprises: a reaction vessel; a rotating shaft rotatably installed in the reaction vessel; an agitating blade which is connected to the rotating shaft and rotates; a plurality of cooling baffles disposed at regular intervals along the inner peripheral surface of the reaction vessel; and a fin which is formed on at least one of the cooling baffles and formed to be elongated along the longitudinal direction of the cooling baffles, wherein the fin protrudes from the outer surface of the cooling baffle toward the rotating shaft.

Description

reactor

Cross-Citation with Related Application(s)

This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0099172, dated August 9, 2022, and all contents disclosed in the document of the Korean Patent Application are included as part of this specification.

The present invention relates to reactors, and in particular to PVC polymerization reactors.

Among PVC quality, fish eyes cause product defects and are particularly critical quality issues in products such as films using soft PVC.

In order to suppress the formation of fish eyes, PVC particles must be formed small so that breakage in the flow is strong. Additionally, in the flow in the tank, the size of the area with low velocity, low turbulence, and low shear rate must be small.

In the poor coalescence zone, the particles do not grow by agglomerating together, and polymerization occurs in one large particle without being decomposed, resulting in the formation of fish eye particles without pores.

One aspect of the present invention is to provide a reactor that can improve PVC quality by reducing the production of fish eyes.

The reactor according to an embodiment of the present invention includes a reaction vessel, a rotating shaft rotatably installed in the reaction vessel, a stirring blade connected to the rotating shaft and rotating, a plurality of cooling baffles disposed at regular intervals along the inner peripheral surface of the reaction vessel, and cooling baffles. It is formed on at least one fin and includes a fin that is formed long along the longitudinal direction of the cooling baffle, and the fin protrudes from the outer surface of the cooling baffle toward the rotation axis.

The distance between the end of the pin and the end of the stirring blade may be 00 to 00.

The thickness of the fin may decrease as the fin moves away from the cooling baffle.

The plurality of baffles may be arranged at a certain angle.

The end of the pin may have a curved surface, and both sides of the pin may have a curved surface.

The stirring blade may be paddle-type.

By installing fins on the cooling baffle as in one embodiment of the present invention, PVC particles can be kept small and the generation of FE can be minimized.

1 is a schematic diagram of a reactor according to an embodiment of the present invention.

Figure 2 is a layout view of a cooling baffle included in the reactor of Figure 1.

3 to 5 are layout views of cooling baffles according to another embodiment of the present invention.

Hereinafter, with reference to the attached drawings, various embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The invention may be implemented in many different forms and is not limited to the embodiments described herein.

Since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to what is shown.

In the drawing, the thickness is enlarged to clearly express various layers and regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated. When a part of a layer, membrane, region, plate, etc. is said to be "on" or "on" another part, this includes not only being "directly above" the other part, but also cases where there is another part in between.

In addition, throughout the specification, when a part is said to "include" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

FIG. 1 is a schematic diagram of a reactor according to an embodiment of the present invention, FIG. 2 is a layout view of a cooling baffle included in the reactor of FIG. 1, and FIGS. 3 to 5 are cooling baffles according to another embodiment of the present invention. This is the layout diagram.

As shown in Figures 1 and 2, the reactor 100 according to an embodiment of the present invention includes a reaction vessel 10 containing reactants, a cooling baffle 20 installed in the reaction vessel 10, and a stirrer 30. ) includes.

The reactor 100 may be, for example, a polymerization reactor for polymer polymerization.

The reaction vessel 10 is not limited in shape, but may have a cylindrical structure and includes a cylindrical side wall portion, a bottom portion, and a cover portion to form a space for accommodating the reaction material. The reaction vessel 10 may be formed as a double-walled structure (not shown), and fluid may circulate inside the double-walled structure, and heat exchange may occur between the fluid and the reactants. That is, a heat exchange jacket may be installed in the reaction vessel.

The stirrer 30 includes a stirring blade 3 installed inside the reaction vessel to rotate the reactant, and a motor 7 having a rotating shaft 5 connected to the stirring blade 3 to rotate the stirring blade. The rotation axis 5 may be located in the center of the reaction vessel 3.

The stirring blade 3 is located inside the reaction vessel 10 and is coupled to the rotation shaft 5 and rotates by the rotation shaft.

The stirring blades 3 may be installed as a set of a plurality of blades at one end of the rotating shaft, and may be installed as a plurality of sets at regular intervals along the longitudinal direction of the rotating shaft for effective stirring of the reactants. One set of stirring blades 3 may include at least 2 to 4 stirring blades. The installation location and number of stirring blades can be selected in various ways depending on need.

The stirring blade 3 may be a paddle type without a pitch, but is not limited thereto and may be a plurality of paddles arranged with pitches.

The baffle 20 is used to improve mixing of the reactants by changing the circumferential flow of the reactants to a vertical flow as the stirring blade 3 rotates, and to effectively remove reaction heat. It is used for heat exchange such as cooling water. It may be composed of pipes through which fluid flows. The baffle 20 maintains a constant temperature of the reactants through heat exchange with the reactants, thereby controlling the temperature, that is, performing a heat removal function. For example, it can maintain the polymerization temperature of 40 to 100 degrees. .

The heat generated during the polymerization reaction can proceed not only through the baffle, but also through the jacket, RC (reflux condenser), etc.

The fluid for heat exchange may have a temperature of approximately 4 degrees Celsius to 35 degrees Celsius in the case of low temperature, and approximately 50 degrees Celsius to 200 degrees Celsius in the case of high temperature.

The baffles 20 may be arranged in plural numbers and spaced apart along the circumferential direction of the reaction vessel 10. A plurality of baffles 20 are installed along the circumferential direction of the reaction vessel 10 at a certain distance from the stirring blade 3, and may preferably be installed at equal intervals along the circumferential direction. For example, the baffles are From 3 to 24 can be arranged.

The baffle may be arranged in one stage as shown in FIG. 2, but the baffle is not limited to this and may be formed by overlapping multiple stages such as two stages and three stages (not shown) as shown in FIG. 3. At this time, the fin may be formed on the baffle stage closest to the center of the reaction vessel.

A fin 40 is formed on at least one baffle 20 among the plurality of baffles. The fin 40 may be formed long along the longitudinal direction of the baffle, and may be a plate-shaped structure that protrudes from the outer surface of the baffle 20 toward the rotation axis of the reactor.

The fin 40 may be formed so that the sum (W) of the width of the baffle on which the fin is formed and the width of the fin is 0.07 to 0.14 times the reactor diameter (D), and preferably 0.14 times.

The thickness of the fin 40 becomes thinner as it moves away from the baffle 20, and may be of a prism type having an isosceles triangle in cross section. However, the fin 40 is not limited thereto and may be of a plate type with a constant thickness. The end of the pin 40 facing the rotation axis of the reactor may have a curved shape so that the reactant can be moved without getting caught in the edge of the pin 40.

In addition, both surfaces of the pin 40 may be flat planes, but are not limited to this and may have an outwardly convex curved surface as in the pin 41 of FIG. 4 or an inwardly concave curved surface as in the pin 42 of FIG. 5. You can have it.

In Figure 2, it is shown that three fins 40 are formed at 120 degree intervals, but this is not limited and fewer or more fins can be installed at a certain angle such as 180 degrees or 60 degrees, and all of them are installed on each baffle. Can be installed.

[Comparative Example 1]

The stirring blades of the reactor are of the paddle type, and are formed in two stages along the rotation axis at regular intervals. Twelve baffles can be installed on the outer wall of the reactor as one-stage double pipes. At this time, the rotation speed (rpm) is 128 (m/sec).

[Example 1]

In the reactor shown in FIG. 2, fins are formed on three of the twelve one-stage baffles arranged at 120-degree intervals. It was operated in the same manner as Comparative Example 1, except that the sum of the width of the baffle to which the fin was attached and the width of the fin (W) was 0.3 m, which was 0.07 with respect to the reactor diameter (D).

[Example 2]

It is the same as Example 1, except that the sum (W) of the width of the baffle to which the fin is attached and the width of the fin is 0.5 m, which is 0.11 with respect to the reactor diameter (D).

[Example 3]

Total baffle width The sum of the width of the baffle to which the fin is attached and the width of the fin (W) The sum of the width of the baffle to which the fin is attached and the width of the fin (W) is 0.66 m, which is equal to the reactor diameter (D). It is the same as Example 1, except that it is 0.14.

	Comparative example	Example 1	Example 2	Example 3
TBW/D(reactor)	0.05	0.07	0.11	0.14
radial (m/sec)	0.65	0.92	1.10	1.17
CFD indicator (sec 2 /m 2 )	2.48	2.63	2.71	2.24
FE increase/decrease rate compared to comparative example	0%	34%	52%	-55%
Increased heat exchange area (m 2 )	0	1.46	5.06	7.94

Table 1 shows the CFD values measured in Comparative Example 1, Examples 1 and 2. At this time, the CFD flow was analyzed using a two-phase Eulerian model.

The CFD indicator is the volume fraction of the area with a turbulence value of 1m ² /sec ³ to 100m ² /sec ³ or more and the volume fraction of the area with a shear rate of 0.5/s to 5/s or less, and the CFD indicator value is The smaller it is, the better the quality of the product is.

Referring to Table 1, it can be seen that the speed in Comparative Example 1 is 0.65, and the speed increases to 0.92, 1.1, and 1.17 in Examples 1, 2, and 3. This shows that the speed increases as the droplet size decreases.

In addition, it can be seen that FE (fish eye) increases in Examples 1 and 2 based on the comparative example, but FE decreases to -55% in Example 3.

In addition, it can be seen that the heat exchange area increases from Comparative Example 1 to Examples 1, 2, and 3.

Meanwhile, looking at the CFD index that evaluates the quality of the product, it is 2.48 in Comparative Example 1, and increases to 2.63 and 2.71 in Examples 1 and 2, showing that the product quality is lower than that of Comparative Example 1. In addition, the CFD index of Example 3 was 2.24, which was lower than that of Comparative Example 1, showing that not only the reaction speed but also product quality was improved.

In the case of Example 3, the radial velocity is high and the CFD index is low, so the quality is improved, and the heat exchange area by the fin is increased, so it is a device that can increase production.

In other words, by installing a pin as in one embodiment of the present invention, the reaction speed can be increased by reducing the droplet size, and the FE (fish eye) quality can be predicted using the CFD indicator, improving responsiveness or product quality. Likewise, the size of the pin can be adjusted as needed.

In this way, by adjusting the diameter ratio of the cooling baffle and the reaction vessel as in the present invention, various effects can be expected, such as reducing FE, increasing speed, and increasing heat exchange area. Therefore, depending on the required process characteristics and quality, the sum of the width of the cooling baffle on which the fins are installed and the width of the fins can be selected within the range of 0.07 to 0.14 times the diameter of the reaction vessel.

Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto and may be implemented with various modifications within the scope of the claims, detailed description of the invention, and accompanying drawings.

Claims (7)

1. reaction vessel,

   A rotating shaft rotatably installed in the reaction vessel,

   A stirring blade connected to the rotating shaft and rotating,

   A plurality of cooling baffles disposed at regular intervals along the inner peripheral surface of the reaction vessel

   A fin is formed on at least one of the cooling baffles and is long along the longitudinal direction of the cooling baffle.

   Including,

   The fin is a reactor in which the fin protrudes from the outer surface of the cooling baffle toward the rotation axis.
2. In paragraph 1:

   A reactor wherein the sum of the width of the cooling baffle on which the fin is installed and the width of the fin is 0.07 to 0.14 times the diameter of the reaction vessel.
3. In paragraph 1:

   A reactor in which the thickness of the fin decreases as the fin moves away from the cooling baffle.
4. In paragraph 1:

   A reactor in which the plurality of baffles are arranged at a certain angle.
5. In paragraph 1:

   The end of the pin is a reactor having a curved surface.
6. In paragraph 1:

   A reactor where both sides of the pin have curved surfaces.
7. In paragraph 1:

   The stirring wing is a paddle-type reactor.

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