Reaction apparatus, method for manufacturing vinyl-based polymer, control device, and agitation apparatus

Abstract

To provide a reaction apparatus used for manufacturing vinyl polymers in which generation of fish eye or attachment of scales are suppressed.SOLUTION: A reaction apparatus comprises a reactor having a straight body part, an agitation shaft and agitation blades, where the dimension of the straight body part, the dimension of the agitation blades, and a set value of the rotational speed of the agitation shaft satisfy a relation shown by N(b / d)(L / D) / n≤6.0. N denotes the number of a plurality of agitation blades, b denotes the maximum value [m] of the blade width of the plurality of agitation blades, d denotes the maximum value [m] of the blade diameter of the plurality of agitation blades, L denotes the length [m] of the straight body part in an extension direction, D denotes, in the case where the straight body part is cut off on a plurality of plane surfaces which is substantially perpendicular to an extending direction of the straight body part and passes through the attaching position of each of the plurality of agitation blades, the maximum value [m] of the diameters of a plurality of inscribed circles approximately inscribed to the straight body part on each cross section by the plurality of plane surfaces, and n denotes a set value of the rotational speed [rps] of the agitation shaft.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a reaction apparatus, a method for producing a vinyl polymer, a control apparatus, and a stirring apparatus.

Background Art

[0002] Patent Document 1 discloses a polymerization apparatus including a baffle and a serpentine pipe through which a refrigerant can flow inside. Patent Document 2 discloses a polymerization apparatus including a baffle and a coiled cooling pipe through which a refrigerant can flow inside. Patent Document 3 discloses a resin synthesis apparatus including a baffle through which a heat medium can flow inside and a stirring means having a helical ribbon blade and an anchor blade. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Laid-Open No. 7-233202 [Patent Document 2] Japanese Patent Laid-Open No. 7-233206 [Patent Document 3] Japanese Patent Laid-Open No. 2013-151621 [General Disclosure]

[0003] In a first aspect of the present invention, a reaction apparatus is provided. The above reaction apparatus includes, for example, a reactor having a cylindrical straight body portion. The above reaction apparatus includes, for example, a stirring shaft configured to be rotatable. In the above reaction apparatus, a part of the stirring shaft is disposed inside the straight body portion. The above reaction apparatus includes, for example, a plurality of stirring blades attached at different positions in the extending direction of the stirring shaft. In the above reaction apparatus, each of the plurality of stirring blades is attached at a different position in the extending direction of the stirring shaft.

[0004] In any of the above reaction apparatuses, the dimension of the straight body portion, the dimension of at least one of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft satisfy, for example, the relationship shown in the following Mathematical Formula 1. (Mathematical Formula 1) N(b / d)(L / D) / n ≦ 6.0

[0005] In Equation 1, N represents the number of a plurality of stirring blades. b represents the maximum value [m] of the blade widths of the plurality of stirring blades. d represents the maximum value [m] of the blade diameters of the plurality of stirring blades. L represents the length [m] in the extending direction of the straight barrel portion. D represents the maximum value [m] of the diameters of a plurality of inscribed circles that are substantially inscribed in the straight barrel portion in each of the cross-sections formed by a plurality of planes, which are planes substantially perpendicular to the extending direction of the straight barrel portion and pass through the respective mounting positions of the plurality of stirring blades, when the straight barrel portion is cut by the plurality of planes. n represents the set value of the rotational speed [rps] of the stirring shaft.

[0006] In any of the above-described reactors, the dimensions of the straight barrel portion, at least one dimension of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft may satisfy the relationship shown in the following Equation 2. In Equation 2, the definitions of N, b, d, L, D, and n are the same as those in Equation 1. (Equation 2) 0.05 ≦ N(b / d)(L / D) / n ≦ 6.0

[0007] Any of the above-described reactors may be provided with a plurality of cooling pipes that are arranged inside the straight barrel portion and through which a refrigerant flows. At least two of the plurality of cooling pipes may have different distances from the inner wall surface of the straight barrel portion. In any of the above-described reactors, the dimensions of the straight barrel portion, at least one dimension of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft may satisfy the relationship shown in the following Equation 3. In Equation 3, the definitions of N, b, d, L, D, and n are the same as those in Equation 1. (Equation 3) 0.15 ≦ N(b / d)(L / D) / n ≦ 5.5

[0008] In any of the above-described reactors, the dimensions of the straight barrel portion, at least one dimension of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft may satisfy the relationship shown in the following Equation 4. In Equation 4, the definitions of N, b, d, L, D, and n are the same as those in Equation 1. (Equation 4) 0.3 ≦ N(b / d)(L / D) / n ≦ 3.0

[0009] In any of the above reaction apparatuses, each of the plurality of cooling pipes may have a meandering portion that extends while repeatedly bending. In any of the above reaction apparatuses, the meandering portion may include a plurality of extending portions that extend linearly or extend in a curved manner. The meandering portion may include a plurality of bending portions that connect the ends of two adjacent extending portions among the plurality of extending portions. In any of the above reaction apparatuses, the ratio of the maximum value of the distance between two adjacent extending portions to the length of the straight body portion in the extending direction may be 0.5 to 15%.

[0010] In any of the above reaction apparatuses, the ratio of the minimum value of the distance between the plurality of cooling pipes and the inner wall surface of the straight body portion to the inner diameter of the straight body portion may be 0.5 to 10%. In any of the above reaction apparatuses, the ratio of the maximum value of the distance between the plurality of cooling pipes and the inner wall surface of the straight body portion to the inner diameter of the straight body portion may be 1 to 30%.

[0011] In any of the above reaction apparatuses, the stirring shaft may be attached to the reactor such that the extending direction of the stirring shaft substantially coincides with the extending direction of the straight body portion. In any of the above reaction apparatuses, the minimum value of the distance between the attachment positions of the plurality of stirring blades on the stirring shaft and the position corresponding to one end of the straight body portion on the stirring shaft may be 0.1 to 0.45 times the length L of the straight body portion in the extending direction.

[0012] In any of the above-described reactors, one end of the straight barrel portion may be the upper end of the straight barrel portion. In the above-described reactor, the mounting position of the stirring blade attached at the lowest position among the plurality of stirring blades on the stirring shaft may be arranged between the first position and the second position of the stirring shaft. In any of the above-described reactors, the first position may be located above the second position when the stirring shaft is attached to the straight barrel portion. In any of the above-described reactors, the distance between the first position and the position corresponding to the lower end of the straight barrel portion on the stirring shaft may be 0.25 times or less of the diameter D of the inscribed circle. In any of the above-described reactors, the distance between the second position and the position corresponding to the lower end of the straight barrel portion on the stirring shaft may be 0.1 times or less of the diameter D of the inscribed circle. In any of the above-described reactors, among the plurality of stirring blades, the mounting positions of the (N - 2) third stirring blades excluding the first stirring blade attached at the uppermost position and the second stirring blade attached at the lowermost position, and the first mounting position which is the mounting position of the first stirring blade and the second mounting position which is the mounting position of the second stirring blade, the maximum value of the distances between the (N - 1) third positions obtained by equally dividing the space between them into (N - 1) parts may be 0.5 times or less of the ratio (D / N) of the diameter D of the inscribed circle to the number N of the plurality of stirring blades.

[0013] In any of the above-described reactors, the internal volume of the reactor may be 40 to 300 m 3 It may be so. In the above-described reactor, the ratio (L / D) of the length L in the extending direction of the straight barrel portion to the diameter D of the inscribed circle may be 1.0 to 3.0. In any of the above-described reactors, the plurality of stirring blades may include paddle blades. Any of the above-described reactors may be provided with a control unit that controls the rotational speed of the stirring shaft so as to satisfy the relationship shown in Equation 1.

[0014] In the second aspect of the present invention, a method for producing a vinyl-based polymer is provided. The above-described production method has, for example, a step of polymerizing a vinyl-based monomer using any of the reactors according to the first aspect to produce a vinyl-based polymer. The above-described production method may have a step of determining the dimensions of the straight barrel portion, at least one dimension of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft.

[0015] In a third aspect of the present invention, a control device is provided. The above control device controls, for example, the rotational speed of the stirring shaft. In the above control device, the stirring shaft is rotatably arranged, for example, inside the reactor. A plurality of stirring blades are attached to the stirring shaft, for example. In the above control device, the reactor has, for example, a cylindrical straight body portion. In the above control device, a part of the stirring shaft is arranged, for example, inside the straight body portion.

[0016] Any of the above control devices controls the rotational speed of the stirring shaft so that, for example, the rotational speed of the stirring shaft satisfies the relationship shown in the following formula 1. (Formula 1) N(b / d)(L / D) / n≦6.0

[0017] In formula 1, N represents the number of a plurality of stirring blades. b represents the maximum value [m] of the blade width of the plurality of stirring blades. d represents the maximum value [m] of the blade diameter of the plurality of stirring blades. L represents the length [m] in the extending direction of the straight body portion. D represents the maximum value [m] of the diameters of a plurality of inscribed circles that are substantially inscribed in the straight body portion in each of the cross-sections formed by a plurality of planes when the straight body portion is cut by a plurality of planes that are planes substantially perpendicular to the extending direction of the straight body portion and pass through the attachment positions of each of the plurality of stirring blades. n represents the set value of the rotational speed [rps] of the stirring shaft.

[0018] In a fourth aspect of the present invention, a stirring device is provided. The above stirring device includes, for example, any of the control devices according to the third aspect above. The above stirring device includes, for example, a stirring shaft. The above stirring device includes, for example, a drive unit that rotates the stirring shaft. In the above stirring device, the control device controls the rotational speed of the stirring shaft by controlling the output of the drive unit.

[0019] Note that the above summary of the invention does not list all the necessary features of the present invention. Also, sub-combinations of these feature groups can also be inventions.

Brief Description of the Drawings

[0020]

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Embodiments for Carrying Out the Invention

[0021] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention. In this specification, when a numerical range is expressed as "A to B", this expression means A or more and B or less.

[0022] According to this embodiment, in a reaction apparatus including a reactor having a cylindrical straight body portion, a stirring shaft, and a plurality of stirring blades, an example of a procedure for controlling or determining the rotation speed of the stirring shaft will be described. In one embodiment of the procedure for controlling or determining the rotation speed of the stirring shaft, a procedure specific to the case where a plurality of cooling pipes are arranged in multiple layers in the radial direction of the inscribed circle of the straight body portion inside the reactor will be described. Therefore, first, with reference to FIGS. 1 to 16, the structure of the reaction apparatus according to the above embodiment will be described. Also, with reference to FIG. 17, the details of the procedure for controlling or determining the rotation speed of the stirring shaft will be described. Further, with reference to FIG. 18, an example of the mounting positions of the plurality of stirring blades on the stirring shaft will be described.

[0023] (Overview of Polymerization Apparatus 100) With reference to FIGS. 1, 2, 3, and 4, the details of an example of the polymerization apparatus 100 will be described. The polymerization apparatus 100 is used, for example, in the production of polymers. The polymerization apparatus 100 may be used for suspension polymerization applications.

[0024] More specifically, the polymerization apparatus 100 is used in the production of vinyl-based polymers. Examples of methods for producing vinyl-based polymers include methods having a step of polymerizing vinyl-based monomers using the polymerization apparatus 100 to produce vinyl-based polymers. The above method for producing vinyl-based polymers has, for example, a step of storing a raw material containing vinyl-based monomers in a reactor arranged in the polymerization apparatus 100. The above method for producing vinyl-based polymers has, for example, a step of initiating the polymerization reaction of the above vinyl-based monomers to produce vinyl-based polymers.

[0025] Figure 1 shows a schematic cross-sectional view of an example of the polymerization apparatus 100. In the present embodiment, the polymerization apparatus 100 includes a reaction vessel 110, a stirrer 120, one or more (sometimes simply referred to as one or more) baffles 130, one or more serpentine cooling pipes 140, one or more serpentine cooling pipes 150, a jacket 170, and a reflux condenser 180. In the present embodiment, the stirrer 120 has a stirring shaft 122, stirring blades 124, and a power mechanism 126. In the present embodiment, the baffle 130 has a main body 132 and one or more supports 134. In the present embodiment, the jacket 170 has a flow path 172 for a heat medium. In the present embodiment, the reflux condenser 180 has a flow path 182 for a heat medium.

[0026] In the present embodiment, the stirring shaft 122 and the stirring blades 124 are disposed inside the reaction vessel 110. In the present embodiment, each of the one or more baffles 130 is disposed inside the reaction vessel 110. In the present embodiment, each of the one or more serpentine cooling pipes 140 is disposed inside the reaction vessel 110. In the present embodiment, each of the one or more serpentine cooling pipes 150 is disposed inside the reaction vessel 110.

[0027] In the present embodiment, the power mechanism 126 is disposed outside the reaction vessel 110. In the present embodiment, the jacket 170 is disposed outside the reaction vessel 110. In the present embodiment, the reflux condenser 180 is disposed outside the reaction vessel 110.

[0028] In the present embodiment, the serpentine cooling pipe 140 and the serpentine cooling pipe 150 are arranged such that the distances from the inner surface of the reaction vessel 110 are different. Specifically, the serpentine cooling pipe 150 is disposed at a position closer to the side surface of the reaction vessel 110 than the serpentine cooling pipe 140. In this case, the distance P C2 between the serpentine cooling pipe 140 and the side surface of the reaction vessel 110 C1 is greater than the distance P

[0029] between the serpentine cooling pipe 150 and the side surface of the reaction vessel 110. C2may be the minimum value of the distance between the center of the cross-section of the serpentine cooling pipe 140 and the side surface of the reaction vessel 110. The distance P between the serpentine cooling pipe 150 and the side surface of the reaction vessel 110 C1 may be the minimum value of the distance between the center of the cross-section of the serpentine cooling pipe 150 and the side surface of the reaction vessel 110. For example, when the serpentine cooling pipe 140 or the serpentine cooling pipe 150 is a circular pipe, the cross-section of the serpentine cooling pipe 140 or the serpentine cooling pipe 150 is circular, and the center of the cross-section of the serpentine cooling pipe 140 or the serpentine cooling pipe 150 is the center of the circle.

[0030] Thus, according to the present embodiment, the heat inside the reaction vessel 110 can be efficiently removed. For example, when the polymerization apparatus 100 is used for producing a polymer, the polymerization apparatus 100 can efficiently remove the reaction heat generated in the polymerization reaction.

[0031] By the way, particularly in the suspension polymerization of a vinyl chloride-based monomer or a monomer mixture mainly composed of a vinyl chloride-based compound (both may be collectively referred to as a vinyl chloride-based monomer), when internal structures such as a cooling coil and a draft tube are arranged inside the reaction vessel 110, the required power of the stirrer 120 increases. In addition, the shape, size, and installation position of the above internal structures affect the mixing performance of the polymerization apparatus 100. Therefore, depending on the internal structure, a portion with slow flow may occur inside the reaction vessel 110. When a portion with slow flow occurs inside the reaction vessel 110, the temperature inside the reaction vessel 110 becomes non-uniform. As a result, the particle size and / or degree of polymerization of the produced polymer become non-uniform, or a polymer scale easily adheres to the inner wall of the reaction vessel 110 or the surface of the internal structure. The above scale may cause fish eyes that impair the quality of the molded product using the polymer.

[0032] In addition, under the condition that the heat removal efficiency is the same, the enlargement of the reaction vessel 110 and the shortening of the reaction time are in a trade-off relationship. Therefore, in order to enlarge the reaction vessel 110 while shortening the reaction time, it is desirable to increase the heat removal efficiency of the polymerization apparatus 100.

[0033] As a method for increasing the heat removal efficiency of the polymerization apparatus 100, it is conceivable to lower the temperature of the refrigerant. However, when the temperature of the refrigerant is lowered, the manufacturing cost of the polymer increases. As another method for increasing the heat removal efficiency of the polymerization apparatus 100, it is conceivable to increase the amount of heat removed by the jacket 170 or the reflux condenser 180. In particular, when it comes to a large polymerization reactor of 40 m 3 or more, since the amount of heat removed by only the heat removal by the jacket 170 is insufficient, it is conceivable to greatly increase the amount of heat removed by the reflux condenser 180. However, when the heat removal load of the reflux condenser 180 is increased, the amount of foaming of the polymer slurry inside the reaction vessel 110 may increase. When the amount of foaming of the polymer slurry increases, the heat removal capacity of the reflux condenser 180 may decrease, or scale of the polymer may adhere to the inside of the reflux condenser 180.

[0034] Also, for example, when increasing the capacity of the polymerization reactor using the polymerization apparatus described in Patent Document 1, if the heat transfer area of the serpentine pipe is insufficient, it may be difficult to shorten the reaction time while maintaining the product quality. On the other hand, in the polymerization apparatus described in Patent Document 2, the heat transfer area can be increased by a relatively simple structure. However, due to the structure of the apparatus, the baffle and the coiled cooling pipe cannot be arranged on substantially the same circumference. Therefore, the ratio of the area where the coiled cooling pipe can be installed to the capacity of the apparatus is relatively small. When increasing the capacity of the polymerization reactor using the polymerization apparatus described in Patent Document 2, if the distance between the coiled cooling pipes is reduced to increase the heat transfer area, the mixing performance of the polymerization apparatus may decrease. In addition, when scale or lumpy reactants are generated on the surface of the coiled cooling pipe due to disturbances or the like, the work inside the tank becomes complicated, so it is difficult to sufficiently remove the above-mentioned scale and the like.

[0035] In contrast, according to the polymerization apparatus 100 according to the present embodiment, the serpentine cooling pipes 140 and 150 are arranged so that the distances from the inner surface of the reaction vessel 110 are different. Thereby, the heat transfer area can be increased by using a relatively simple structure that has little influence on the mixing performance of the polymerization apparatus 100. Further, according to the polymerization apparatus 100 according to the present embodiment, the degree of freedom regarding the installation positions of the serpentine cooling pipes 140 and 150 is large. For example, at least one of the one or more serpentine cooling pipes 140 and the one or more serpentine cooling pipes 150 and the baffle 130 can be arranged on substantially the same circumference. Thereby, while reducing the influence of the serpentine cooling pipe 150 on the mixing performance of the polymerization apparatus 100, the heat transfer area of the entire apparatus can be increased.

[0036] (Overview of each part of the polymerization apparatus 100) In the present embodiment, the reaction vessel 110 stores the raw materials for the synthesis reaction. When the polymerization apparatus 100 is used for the production of a polymer, for example, after a polymerizable monomer, a polymerization initiator, an aqueous medium, a dispersion aid, etc. are charged into the reaction vessel 110, the polymerization is started. As the dispersion aid, for example, any surfactant can be used.

[0037] The reaction vessel 110 has, for example, a cylindrical shape. The reaction vessel 110 may have a cylindrical shape or a rectangular tube shape. The reaction vessel 110 is installed, for example, such that the extending direction of the reaction vessel 110 (the z direction in the figure) is in the vertical direction. The reaction vessel 110 includes, for example, a straight body portion and a mirror portion. In the figure, the total length of the reaction vessel 110 in the extending direction is denoted as H.

[0038] Examples of the shape of the cross section (which may be referred to as a cross-sectional view) obtained by cutting the reaction vessel 110 with a plane perpendicular to the extending direction of the reaction vessel 110 (the xy plane in the figure) include a circular shape, an elliptical shape, and a polygonal shape. Note that the shape of the cross section of the reaction vessel 110 may be a shape that can be substantially regarded as a circular shape, an elliptical shape, or a polygonal shape.

[0039] The internal volume of the reaction vessel 110 is not particularly limited, but the internal volume of the reaction vessel 110 is, for example, 1 to 300 ml. 3 The lower limit of the internal volume of the reaction vessel 110 is 40 ml. 3 It may be 80m 3 may be 100m 3 It may be 120m 3 It may be 130m 3 It may be 150m 3 It may be 200m 3 It may be 250m 3 The upper limit of the internal volume of the reaction vessel 110 may be 300 ml. 3 The upper limit of the internal volume of the reaction vessel 110 is 350 ml. 3 It may be 400m 3 The larger the internal volume of the reaction vessel 110, the more advantageous the improvement in cooling capacity according to this embodiment.

[0040] The internal capacity of the reaction vessel 110 is determined as the capacity when the reaction vessel 110 stores liquid up to a predetermined upper limit position of the reaction vessel 110. The internal capacity of the reaction vessel 110 is, for example, the internal volume of the reaction vessel 110 when no internal structure such as a stirring shaft, blades, baffles, coils, etc. is disposed inside the reaction vessel 110.

[0041] As described above, there is a trade-off between increasing the size of the reaction vessel 110 and shortening the reaction time. 3 If the internal volume of the reaction vessel 110 is more than 80 m, the heat removal efficiency of the polymerization apparatus 100 becomes insufficient, and it becomes difficult to shorten the reaction time while increasing the size of the reaction vessel 110. 3 In the above cases, the effects of the polymerization apparatus 100 according to this embodiment are more pronounced. The details of the reaction vessel 110 will be described later.

[0042] In this embodiment, the stirrer 120 stirs the liquid stored inside the reaction vessel 110. In this embodiment, the stirring shaft 122 holds the stirring blades 124 and rotates the stirring blades 124. In this embodiment, the stirring blades 124 are attached to the stirring shaft 122 and stir the liquid stored inside the reaction vessel 110.

[0043] The shape of the stirring blades 124 is not particularly limited, but examples of the shape of the stirring blades 124 include Faudler blades, Blumargin blades, paddle blades, inclined paddle blades, turbine blades, propeller blades, and combinations thereof. Thereby, when the stirring shaft 122 rotates, a discharge flow radially outward from the stirring shaft 122 is generated. The number of blades of the stirring blades 124 is not particularly limited, but examples of the number of the above-mentioned blades are 2 to 6. The installation position and the installation quantity of the stirring blades 124 are not particularly limited, but the stirring blades 124 are preferably installed in multiple stages. Examples of the number of stages of the stirring blades 124 are 2 to 6 stages.

[0044] In this embodiment, the power mechanism 126 rotates the stirring shaft 122. The power mechanism 126 includes, for example, a power unit (not shown) that generates power and a power transmission unit (not shown) that transmits the power generated by the power unit to the stirring shaft 122. Examples of the power unit include an electric motor. Examples of the power transmission unit include a speed reducer.

[0045] The rotation speed of the stirring shaft 122 and the shape, size, number of blades, installation position, installation quantity, and installation interval C of the stirring blades 124 i are appropriately determined according to the use of the polymerization apparatus 100. The rotation speed of the stirring shaft 122 and the shape, size, number of blades, installation position, installation quantity, and installation interval C of the stirring blades 124 i are determined in consideration of, for example, the internal volume of the reaction vessel 110, the shape of the reaction vessel 110, the internal structures arranged inside the reaction vessel 110, the configuration of the heat removal means, the heat removal capacity, and the composition of the raw materials charged for polymerization.

[0046] For example, when the polymerization apparatus 100 is used for suspension polymerization, the stirring energy applied to the contents (in this case, an aqueous suspension mixture) is 80 to 200 kgf·m / s·m 3 The rotational speed of the stirring shaft 122 is determined so as to be this value. Here, the "stirring energy" applied to the contents is the net energy required for stirring per unit amount of the contents (sometimes referred to as the unit content volume), obtained by subtracting various energy losses B such as motor efficiency, conduction loss, and mechanical loss from the energy A applied to the drive motor for the stirrer arranged in the power mechanism 126 during the operation of the polymerization apparatus 100. Examples of the above unit amount include unit mass and unit volume. For example, if the volume of the contents is C, the stirring energy is calculated by the following formula E. (Formula E) (A - B) / C [kgf·m / s·m 3

[0047] The energy applied to the drive motor for the stirrer can be electrically measured using a measuring instrument such as a wattmeter, for example. Also, the stirring energy can be easily adjusted by changing the rotational speed of the stirring shaft 122.

[0048] The rotational speed of the stirring shaft 122 is set to, for example, 10 to 1000 [rpm]. The above set value can be preferably adopted, for example, when the polymerization apparatus 100 is used for suspension polymerization. Examples of the method for determining the rotational speed of the stirring shaft 122 so that the stirring energy is within the above numerical range include (i) a method by a scale-up test and (ii) a method using a relational expression such as an experimental formula or an empirical formula.

[0049] ​In one embodiment, the rotational speed of the stirring shaft 122 in the polymerization apparatus 100 is determined, for example, based on a polymerization test in a pilot plant carried out in advance. Generally, the scale-up from the pilot plant to the polymerization apparatus 100 is carried out such that the stirring state of the polymerization apparatus 100 substantially coincides with the stirring state of the pilot plant. For example, in the pilot plant and the polymerization apparatus 100, the shapes and sizes of the reaction vessel 110 and the internal structures such as the stirring blade 124, the baffle 130, the serpentine cooling pipe 140, and the serpentine cooling pipe 150, as well as their arrangements, are determined so as to be similar.

[0050] Therefore, according to one embodiment, the rotational speed of the stirring shaft 122 in the polymerization apparatus 100 can be determined such that the stirring energy in the polymerization apparatus 100 and the stirring energy in the pilot plant are substantially the same. As described above, the stirring energy is calculated, for example, as "(A - B) / C". As a method for determining the rotational speed of the stirring shaft 122 based on the stirring energy, any known method can be adopted.

[0051] The rotational speed of the stirring shaft 122 in the pilot plant is determined, for example, by the following procedure. For example, through a polymerization test using the pilot plant, the relationship between the rotational speed of the stirring shaft 122 in the pilot plant and the quality of the polymer is obtained. Thereby, the rotational speed of the stirring shaft 122 at which a polymer of the desired quality is obtained is determined. The above quality is not particularly limited, but examples of the above quality include, for example, particle size.

[0052] Specifically, in a polymerization test using the pilot plant, the polymerization temperature is set according to the reduced viscosity (which may be referred to as the K value) of the target polymer. Here, there is a correlation between the polymerization temperature and the average degree of polymerization of the polymer, and the K value of the polymer is widely used as an index representing the average degree of polymerization of the polymer.

[0053] In addition, in the polymerization test using a pilot plant, the polymerization time is determined according to the heat removal capacity of the pilot plant. For example, the polymerization time is determined so that the amount of heat generated by the reaction does not exceed the heat removal capacity of the pilot plant according to (i) the charged amount of the monomer as the starting material, (ii) the amount of the polymerization initiator added, and (iii) the heat removal capacity of the pilot plant.

[0054] Thus, when the polymerization time is set so that the pilot plant has sufficient heat removal capacity, by setting the polymerization temperature according to the target value of the K value, a polymer having the target average degree of polymerization can be produced. Therefore, for example, polymerization tests are carried out for each of a plurality of conditions where the polymerization temperature and the polymerization time are the same and the rotation speed of the stirring shaft 122 is different.

[0055] Based on a plurality of test results with different rotation speeds of the stirring shaft 122, the relationship between the rotation speed of the stirring shaft 122 in the pilot plant and the quality of the polymer can be obtained. Thereby, if the target value of the polymer quality is determined, the rotation speed of the stirring shaft 122 that can obtain a polymer of the target quality can be determined.

[0056] When the polymerization time is set so that the pilot plant has sufficient heat removal capacity, by setting the polymerization temperature according to the target value of the K value, a polymer having the target average degree of polymerization can be produced. On the other hand, when the heat removal capacity of the pilot plant is insufficient for the set polymerization time, the polymerization temperature rises due to the heat generated by the polymerization reaction. As described above, there is a correlation between the polymerization temperature and the average degree of polymerization of the produced polymer. Therefore, when the polymerization temperature rises, the error between the K value of the produced polymer and the target value of the K value becomes larger. Also, depending on the rate of increase in the polymerization temperature, the reaction may become uncontrollable.

[0057] Thus, the K value of the produced polymer can be adopted as an index regarding the heat removal capacity of the polymerization apparatus 100. For example, when a polymer is produced using the polymerization apparatus 100, when the target K value is obtained for the set polymerization time, the polymerization apparatus 100 can be determined to have sufficient heat removal capacity.

[0058] As described above, the scale-up from the pilot plant to the polymerization apparatus 100 can be carried out such that the stirring state of the polymerization apparatus 100 and the stirring state of the pilot plant are substantially the same. For example, when the ratio of the size of each internal structure disposed inside the reaction vessel 110 to the inner diameter and / or the height of the straight body portion of the reaction vessel 110 in the target polymerization apparatus 100 is substantially the same as the ratio of the size of each internal structure in the pilot plant to the inner diameter and / or the height of the straight body portion of the reaction vessel of the pilot plant, and when the stirring energy in the polymerization apparatus 100 and the stirring energy in the pilot plant are substantially the same, the stirring state of the scaled-up polymerization apparatus 100 and the stirring state of the pilot plant are substantially the same.

[0059] For example, between the pilot plant and the target polymerization apparatus 100, the size of the baffle 130 in the target polymerization apparatus 100 is determined such that the ratio of the length in the extending direction (the vertical direction in the figure) of the baffle 130 to the height of the straight body portion of the reaction vessel 110 is substantially the same. Between the pilot plant and the target polymerization apparatus 100, the size of the baffle 130 in the target polymerization apparatus 100 is determined such that the ratio of the length in the direction substantially perpendicular to the extending direction of the baffle 130 (the left-right direction in the figure) to the inner diameter (sometimes referred to as the inner diameter) inside the reaction vessel 110 is substantially the same. Between the pilot plant and the target polymerization apparatus 100, the number and arrangement of the baffles 130 in the target polymerization apparatus 100 are determined such that the number and arrangement of the baffles 130 are substantially the same. The same applies to other structures (for example, the stirring blade 124, the serpentine cooling pipe 140, the serpentine cooling pipe 150, etc.).

[0060] Further, as described above, once the target value of the polymer quality in the scaled-up polymerization apparatus 100 is determined, the rotational speed of the stirring shaft 122 in the scaled-up polymerization apparatus 100 can be determined based on the relationship between the rotational speed of the stirring shaft 122 in the above-described pilot plant and the polymer quality. Specifically, first, the rotational speed of the stirring shaft 122 in the pilot plant is determined based on (i) the target value of the polymer quality in the polymerization apparatus 100 and (ii) the relationship between the rotational speed of the stirring shaft 122 in the pilot plant and the polymer quality. Next, the rotational speed of the stirring shaft 122 in the polymerization apparatus 100 is determined such that the stirring energy in the polymerization apparatus 100 and the stirring energy in the pilot plant are substantially the same.

[0061] Thereby, without precisely measuring the stirring energy per unit internal volume [kgf·m / s·m i while considering (i) the shape, size, number of blades, installation position, installation quantity, and installation interval C of the stirring blades 124 of the target polymerization apparatus 100 3 , and (ii) the internal volume of the reaction vessel 110, the shape of the reaction vessel 110, and the internal structures arranged inside the reaction vessel 110, etc., the rotational speed of the stirring shaft 122 of the target polymerization apparatus 100 can be determined. Note that the rotational speed of the stirring shaft 122 in the target polymerization apparatus 100 may be determined based on the simulation results of the polymerization test.

[0062] In another embodiment, the rotational speed of the stirring shaft 122 in the polymerization apparatus 100 is determined such that the dimension of the straight barrel portion of the reaction vessel 110, the dimension of at least one of the plurality of stirring blades 124, and the set value of the rotational speed of the stirring shaft 122 satisfy the relationship shown in the following mathematical formula 1. (Mathematical formula 1) N(b / d)(L / D) / n ≦ 6.0

[0063] In Equation 1, N represents the number of the plurality of stirring blades 124. b represents the maximum value [m] of the blade width of the plurality of stirring blades 124. d represents the maximum value [m] of the blade diameter of the plurality of stirring blades 124. L represents the length [m] of the straight body portion of the reaction vessel 110 in the extending direction. D represents the maximum value [m] of the diameters of a plurality of inscribed circles that are substantially inscribed in the straight body portion in each of the cross-sections formed by a plurality of planes, where the plurality of planes are planes that are substantially perpendicular to the extending direction of the straight body portion and pass through the mounting positions of the respective plurality of stirring blades 124, when the straight body portion of the reaction vessel 110 is cut by the plurality of planes. When the reaction vessel 110 has a cylindrical straight body portion, D is the inner diameter [m] of the straight body portion. n represents the set value of the rotational speed [rps] of the stirring shaft 122.

[0064] The blade diameter of the stirring blade 124 may be the rotational diameter of the stirring blade 124. The rotational diameter of the stirring blade 124 may be the diameter of the rotating body obtained by rotating the stirring blade 124 around the stirring shaft 122. The blade diameter of the stirring blade 124 may be the overall length of the stirring blade 124 in a direction that is substantially perpendicular to the extending direction of the stirring shaft 122 (for example, the left-right direction in FIG. 1) when the stirring blade 124 is attached to the stirring shaft 122.

[0065] The blade width of the stirring blade 124 may be the height of the rotating body obtained by rotating the stirring blade 124 around the stirring shaft 122. The blade width of the stirring blade 124 may be the overall length of the stirring blade 124 in a direction that is substantially parallel to the extending direction of the stirring shaft 122 (for example, the up-down direction in FIG. 1) when the stirring blade 124 is attached to the stirring shaft 122.

[0066] According to the present embodiment, the rotational speed of the stirring shaft 122 can be more easily determined as compared with the case where the rotational speed of the stirring shaft 122 is determined based on a polymerization test in a pilot plant conducted in advance. Further, even in the case where the rotational speed of the stirring shaft 122 is determined based on a polymerization test in a pilot plant conducted in advance, the rotational speed of the stirring shaft 122 can be more easily determined by considering the relationship of Equation 1 above.

[0067] The dimensions of the straight body portion of the reaction vessel 110, the dimensions of at least one of the plurality of stirring blades 124, and the set value of the rotational speed of the stirring shaft 122 are preferably determined so as to satisfy the relationship shown in the following mathematical formula 2. (Mathematical formula 2) 0.05 ≦ N(b / d)(L / D) / n ≦ 6.0

[0068] When the polymerization apparatus 100 includes one or more serpentine cooling pipes 140 or one or more serpentine cooling pipes 150, the dimensions of the straight body portion of the reaction vessel 110, the dimensions of at least one of the plurality of stirring blades 124, and the set value of the rotational speed of the stirring shaft 122 are preferably determined so as to satisfy the relationship shown in the following mathematical formula 3. (Mathematical formula 3) 0.15 ≦ N(b / d)(L / D) / n ≦ 5.5

[0069] When the polymerization apparatus 100 includes one or more serpentine cooling pipes 140 and one or more serpentine cooling pipes 150, the dimensions of the straight body portion of the reaction vessel 110, the dimensions of at least one of the plurality of stirring blades 124, and the set value of the rotational speed of the stirring shaft 122 are preferably determined so as to satisfy the relationship shown in the following mathematical formula 4. (Mathematical formula 4) 0.3 ≦ N(b / d)(L / D) / n ≦ 5.5

[0070] In one embodiment, based on the dimensions of the straight body portion of the reaction vessel 110, the dimensions of at least one of the plurality of stirring blades 124, and Mathematical formula 1, the set value of the rotational speed of the stirring shaft 122 in the polymerization apparatus 100 is determined. In other embodiments, based on the set value of the rotational speed of the stirring shaft 122 in the polymerization apparatus 100 and Mathematical formula 1, the dimensions of the straight body portion of the reaction vessel 110 and the dimensions of at least one of the plurality of stirring blades 124 are determined. Details of these embodiments will be described in connection with FIG. 17 described later.

[0071] In this embodiment, the baffle 130 improves the mixing performance of the polymerization apparatus 100. For example, the baffle 130 improves the vertical mixing performance inside the reaction vessel 110. The installation position of the baffle 130 is not particularly limited. For example, the baffle 130 is arranged near the inner wall of the reaction vessel 110. The baffle 130 may be supported by the side wall of the reaction vessel 110. In other embodiments, the baffle 130 is supported by the top plate or the bottom plate of the reaction vessel 110 and is arranged near the stirring blade 124. When the polymerization apparatus 100 is used for producing a polymer, the upper end of the baffle 130 may be arranged so as to be immersed in the liquid phase, or may be arranged so as not to be immersed in the liquid phase.

[0072] The number of the baffles 130 is preferably about 1 to 12, more preferably about 2 to 8, still more preferably about 3 to 6, and even more preferably about 4 to 6. It is preferable that an even number of baffles 130 are arranged substantially symmetrically around the extension axis (which may be referred to as the central axis) of the reaction vessel 110. Thereby, the mixing performance of the polymerization apparatus 100 is further improved, and the retention of the liquid is suppressed. As a result, the generation of scale can be suppressed.

[0073] In this embodiment, the main body 132 of the baffle 130 improves the mixing performance of the polymerization apparatus 100. The shape of the main body 132 is not particularly limited. For example, the main body 132 has a plate-like or cylindrical shape extending substantially parallel to the extension direction of the reaction vessel 110. When the main body 132 has a cylindrical shape, the diameter of the main body 132 may be 40 to 500 mm. The length Bh (which may be referred to as the height Bh) of the main body 132 in the extension direction (the z direction in the figure) is not particularly limited.

[0074] The length Bw (which may be referred to as the width Bw) of the main body 132 in the direction substantially perpendicular to the extension direction (the x or y direction in the figure) is not particularly limited. The ratio of the width Bw of the main body 132 to the inner diameter of the reaction vessel 110 may be 1 to 10%, may be 2.5 to 7.5%, or may be 3 to 7%.

[0075] When the main body 132 has a cylindrical shape, the ratio of the total cross-sectional area of one or more main bodies 132 each having a cylindrical shape to the cross-sectional area of the straight body part of the reaction vessel 110 may be 0.4 to 3%. When the above ratio is less than 0.4%, the function as a baffle plate is insufficient, and the vertical mixing inside the reaction vessel 110 may become insufficient. For example, when the polymerization apparatus 100 includes a single baffle 130, the above ratio may be less than 0.4%. For example, in the suspension polymerization of a vinyl chloride monomer, when the vertical mixing inside the reaction vessel 110 becomes insufficient, the particle size distribution of the produced polymer may become broad. As a result, when the produced polymer is formed into a sheet shape, for example, fish eyes may increase and the quality of the molded product may deteriorate.

[0076] On the other hand, when the above ratio exceeds 3%, the required power of the stirrer 120 excessively increases. Also, the fluidity of the liquid between the baffle 130 and the inner wall surface of the reaction vessel 110 may decrease. As a result, scale may easily adhere to the reaction vessel 110 or the structures inside the reaction vessel 110. For example, when the polymerization apparatus 100 includes more than eight baffles 130, depending on the design of the polymerization apparatus 100, the above ratio may exceed 3%.

[0077] At least one main body 132 of the baffle 130 may have a flow path for allowing a heat medium to flow through. The above flow path may be formed inside the main body 132 or arranged outside the main body 132. The above flow path may be a single pipe or may have a double pipe structure.

[0078] The heat medium may be a known refrigerant. Examples of the refrigerant include water, brine, freon, and other liquefied gases. When a liquefied gas is used as the refrigerant, the liquefied gas may function as a refrigerant by evaporating inside the serpentine cooling pipe 140. The linear velocity of the refrigerant may be about 0.1 to 6.0 m / s.

[0079] The main body 132 is connected to the inner wall surface of the reaction vessel 110 via a support 134, for example. The distance between the main body 132 and the inner wall surface of the polymerization apparatus 100 is preferably 40 mm or more. When the above distance is less than 40 mm, a polymer scale may easily adhere between the inner wall surface of the reaction vessel 110 and the baffle 130 near the gas-liquid interface inside the reaction vessel 110. Details of the main body 132 will be described later.

[0080] In the present embodiment, the support 134 holds the main body 132. For example, one end of the support 134 contacts the inner wall surface of the reaction vessel 110, and the other end of the support 134 contacts the main body 132. As described above, the support 134 may hold the main body 132 so that the distance between the main body 132 and the inner wall surface of the polymerization apparatus 100 is 40 mm or more.

[0081] In the present embodiment, a flow path for allowing a heat medium to flow is formed inside the serpentine cooling pipe 140. The serpentine cooling pipe 140 may be a single pipe. The serpentine cooling pipe 140 is arranged at a position closer to the central axis of the reaction vessel 110 than the serpentine cooling pipe 150. The number of the serpentine cooling pipes 140 is preferably about 1 to 12, more preferably about 2 to 8, still more preferably about 3 to 6, and even more preferably about 4 to 6. It is preferable that an even number of serpentine cooling pipes 140 are arranged substantially symmetrically around the central axis of the reaction vessel 110.

[0082] The heat medium may be a known refrigerant. Examples of the refrigerant include water, brine, freon, and other liquefied gases. When a liquefied gas is used as the refrigerant, the liquefied gas may function as a refrigerant by evaporating inside the serpentine cooling pipe 140. The linear velocity of the refrigerant may be about 0.1 to 6.0 m / s.

[0083] In the present embodiment, at least a part of the serpentine cooling pipe 140 extends while repeatedly bending. Among the serpentine cooling pipes 140, the length Ph in the extending direction of the portion that extends while repeatedly bending may be smaller than the length Bh in the extending direction (the z direction in the figure) of the main body 132 of the baffle 130, may be substantially the same as the Bh, or may be larger than the Bh. Thereby, the heat transfer area per installation area becomes large.

[0084] In the example shown in FIG. 1, the serpentine cooling pipe 140 extends substantially parallel to the extending direction of the reaction vessel 110 while repeatedly bending. In the example shown in FIG. 1, the entire serpentine cooling pipe 140 extends while repeatedly bending. The ratio of the length Ph in the extending direction of the portion of the serpentine cooling pipe 140 that extends while repeatedly bending to the total length Pt (not shown) in the extending direction of the serpentine cooling pipe 140 may be 0.25 or more, may be 0.5 or more, may be 0.75 or more, may be 0.8 or more, or may be 0.9 or more.

[0085] When the polymerization apparatus 100 is used for producing a polymer, the serpentine cooling pipe 140 may be arranged such that the upper end of the serpentine cooling pipe 140 is immersed in the liquid phase. This is because if the upper part of the serpentine cooling pipe 140 is exposed to the gas phase, the heat transfer efficiency will decrease and the scale of the polymer will easily adhere to the serpentine cooling pipe 140. At the end of polymerization, the gas-liquid interface drops due to liquid shrinkage. Therefore, it is preferable that the serpentine cooling pipe 140 is arranged at a position where there is a sufficient distance between the upper end of the serpentine cooling pipe 140 and the gas-liquid interface even at the end of polymerization. Details of the serpentine cooling pipe 140 will be described later.

[0086] In this embodiment, a serpentine cooling pipe 150 has a flow path formed therein for allowing a heat medium to flow therethrough. The serpentine cooling pipe 150 may be a single pipe. The serpentine cooling pipe 150 is arranged at a position closer to the side wall of the reaction vessel 110 than the serpentine cooling pipe 140. The number of the serpentine cooling pipes 150 is preferably about 1 to 12, more preferably about 2 to 8, still more preferably about 3 to 6, and even more preferably about 4 to 6. The number of the serpentine cooling pipes 150 may be the same as or different from the number of the serpentine cooling pipes 140. It is preferable that an even number of the serpentine cooling pipes 150 are arranged substantially symmetrically around the central axis of the reaction vessel 110.

[0087] The heat medium may be a known refrigerant. Examples of the refrigerant include water, brine, freon, and other liquefied gases. When a liquefied gas is used as the refrigerant, the liquefied gas may function as a refrigerant by evaporating inside the serpentine cooling pipe 140. The linear velocity of the refrigerant may be about 0.1 to 6.0 m / s.

[0088] In this embodiment, at least a part of the serpentine cooling pipe 150 extends while repeatedly bending. Among the serpentine cooling pipes 150, the length Ph in the extending direction of the portion that extends while repeatedly bending may be smaller than, substantially the same as, or larger than the length Bh in the extending direction (the z direction in the figure) of the main body 132 of the baffle 130. Thereby, the heat transfer area per installation area becomes large.

[0089] In the example shown in FIG. 1, the serpentine cooling pipe 150 extends substantially parallel to the extending direction of the reaction vessel 110 while repeatedly bending. In the example shown in FIG. 1, the entire serpentine cooling pipe 150 extends while repeatedly bending. The ratio of the length Ph in the extending direction of the portion that extends while repeatedly bending among the serpentine cooling pipes 150 to the total length Pt in the extending direction (not shown) of the serpentine cooling pipe 150 may be 0.25 or more, 0.5 or more, 0.75 or more, 0.8 or more, or 0.9 or more.

[0090] When the polymerization apparatus 100 is used for producing a polymer, the serpentine cooling pipe 150 may be arranged such that the upper end of the serpentine cooling pipe 150 is immersed in the liquid phase. This is because if the upper part of the serpentine cooling pipe 150 is exposed to the gas phase, the heat transfer efficiency will decrease and the polymer scale will easily adhere to the serpentine cooling pipe 150. At the end of the polymerization, the gas-liquid interface drops due to liquid shrinkage. Therefore, it is preferable that the serpentine cooling pipe 150 is arranged at a position where there is a sufficient distance between the upper end of the serpentine cooling pipe 150 and the gas-liquid interface even at the end of the polymerization.

[0091] In one embodiment, the flow direction of the refrigerant in the serpentine cooling pipe 150 is set such that the refrigerant flows from below the reaction vessel 110 to above the reaction vessel 110. In other embodiments, the flow direction of the refrigerant in the serpentine cooling pipe 150 is set such that the refrigerant flows from above the reaction vessel 110 to below the reaction vessel 110.

[0092] For example, the liquid returned from the reflux condenser 180 is at a lower temperature and has a higher density than the liquid inside the reaction vessel 110. Therefore, in the vicinity of the inlet of the liquid returned from the reflux condenser 180, the liquid inside the reaction vessel 110 tends to flow from above to below. Thus, for example, the serpentine cooling pipe 150 arranged in the vicinity of the inlet of the liquid returned from the reflux condenser 180 can be configured such that the refrigerant flows from below the reaction vessel 110 to above the reaction vessel 110. Details of the serpentine cooling pipe 150 will be described later.

[0093] In the present embodiment, the jacket 170 heats or cools the reaction vessel 110 from the outside of the reaction vessel 110. As described above, the jacket 170 has a flow path 172 configured to allow the heat medium to flow. The jacket 170 adjusts the heating amount and heat removal amount of the reaction vessel 110 by controlling at least one of the temperature and flow rate of the heat medium flowing through the flow path 172.

[0094] The heat medium may be a known refrigerant. Examples of the refrigerant include water, brine, freon, various liquefied gases, etc. As the refrigerant, a liquid refrigerant is preferably used. When a liquefied gas is used as the refrigerant, the liquefied gas may function as a refrigerant by evaporating inside the serpentine cooling pipe 140. The linear velocity of the refrigerant may be about 0.1 to 6.0 m / s.

[0095] In this embodiment, the reflux condenser 180 is used for heat removal from the reaction vessel 110. For example, steam from the reaction vessel 110 is supplied to the reflux condenser 180. The reflux condenser 180 cools and liquefies the above steam. The reflux condenser 180 returns the liquid generated by the above cooling to the reaction vessel 110. As described above, the reflux condenser 180 has a flow path 182 configured to allow the heat medium to flow through. The reflux condenser 180 cools the steam from the reaction vessel 110 by heat exchange between the heat medium flowing through the flow path 182 and the steam from the reaction vessel 110. By controlling at least one of the temperature and flow rate of the heat medium flowing through the flow path 182, the amount of heat removed from the reaction vessel 110 can be adjusted.

[0096] (Relationship of heat removal means) As described above, in this embodiment, the reaction vessel 110 has, as heat removal means, a baffle 130, a serpentine cooling pipe 140, a serpentine cooling pipe 150, a jacket 170, and a reflux condenser 180. The ratio of the amount of heat removed by each heat removal device to the total heat generation amount is not particularly limited. The above ratio is determined, for example, in consideration of the quality of the polymer to be produced, the manufacturing cost, etc. For example, the ratio of the amount of heat removed by the baffle 130 to the total heat generation amount is preferably 10 to 30%. The ratio of the total amount of heat removed by the serpentine cooling pipe 140 and the serpentine cooling pipe 150 to the total heat generation amount is preferably 10 to 50%. The ratio of the amount of heat removed by the jacket 170 to the total heat generation amount is preferably 20 to 40%. The ratio of the amount of heat removed by the reflux condenser 180 to the total heat generation amount is preferably 10 to 50%.

[0097] Further, the serpentine cooling pipes 140 and 150 are designed such that the ratio of the total surface area of the serpentine cooling pipes 140 and 150 to the internal volume of the reaction vessel 110 is 0.1 to 0.9 [m 2 / m 3 . It is preferably designed in this way. The above ratio is more preferably 0.5 to 0.7 [m 2 / m 3 . Thereby, the ratio of the total heat removal amount of the serpentine cooling pipes 140 and 150 to the total heat generation amount can be made 10 to 50%.

[0098] (Materials of each part of the polymerization apparatus 100) The materials of each part of the polymerization apparatus 100 are appropriately determined in consideration of mechanical strength, corrosion resistance, heat transfer performance, etc. For example, as the materials used for the stirring shaft 122, the stirring blade 124, the baffle 130, the serpentine cooling pipe 140, and the serpentine cooling pipe 150, stainless steels such as high-chromium high-purity ferritic stainless steel, duplex stainless steel, and austenitic stainless steel are preferable. These materials are excellent in heat transfer performance and corrosion resistance. Further, as the material of the inner wall surface of the reaction vessel 110, clad steel containing stainless steel is exemplified. The material of the outer layer of the above clad steel is preferably carbon steel, and the material of the inner layer of the clad steel is preferably stainless steel.

[0099] (Use of the polymerization apparatus 100) As described above, the polymerization apparatus 100 is used for producing polymers. The polymerization method may be suspension polymerization or emulsion polymerization. More specifically, the polymerization apparatus 100 is used for the purpose of polymerizing various vinyl monomers, for example, olefins such as ethylene and propylene, vinyl halides such as vinyl chloride and vinylidene chloride, vinyl esters such as vinyl acetate, vinyl ethers such as ethyl vinyl ether, (meth)acrylic acid esters such as methyl methacrylate, metal salts or esters of maleic acid or fumaric acid, aromatic vinyls such as styrene, diene monomers such as butadiene, chloroprene, and isoprene, acrylonitrile, etc. to produce polymers. The polymerization apparatus 100 is particularly preferably used for the purpose of polymerizing vinyl chloride or a monomer mixture mainly composed of the same to produce polymers.

[0100] When a polymer is produced using the polymerization apparatus 100, each raw material is supplied from the supply port (not shown) of the polymerization apparatus, and when the temperature of the reaction compound charged into the inside of the reaction vessel 110 reaches a predetermined temperature, a refrigerant is circulated through each of the baffle 130, the serpentine cooling pipe 140, the serpentine cooling pipe 150, and the jacket 170, and heat removal of the reaction compound is started. On the other hand, it is preferable that the timing of starting heat removal by the reflux condenser 180 is after the polymerization conversion rate reaches 4%, and more preferably at the time when the polymerization conversion rate is 4 to 20%.

[0101] Even when a polymer is produced using the polymerization apparatus 100, various polymerization conditions may be the same as known polymerization conditions. Examples of the above polymerization conditions include the charging ratio of raw materials and the like, the charging method of raw materials and the like, and the polymerization temperature.

[0102] For example, when a vinyl chloride-based polymer is produced by suspension polymerization using the polymerization apparatus 100, the charging of an aqueous medium, a vinyl chloride monomer, and optionally other comonomers, a dispersion aid, a polymerization initiator, etc. is carried out in the same manner as in known methods for producing vinyl chloride-based polymers. Also, the polymerization conditions may be the same as in known methods for producing vinyl chloride-based polymers.

[0103] As the monomers to be polymerized, vinyl chloride alone or a monomer mixture mainly composed of vinyl chloride (vinyl chloride: 50% by mass or more) can be used. Examples of the comonomers copolymerizable with vinyl chloride include vinyl esters such as vinyl acetate and vinyl propionate; acrylic acid esters or methacrylic acid esters such as methyl acrylate and ethyl acrylate; olefins such as ethylene and propylene; maleic anhydride; acrylonitrile; styrene; vinylidene chloride; and other monomers copolymerizable with vinyl chloride.

[0104] As the above-mentioned dispersion aids, compounds usually used in the polymerization of vinyl chloride in an aqueous medium are used. Examples of the above-mentioned dispersion aids include water-soluble cellulose ethers such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, and hydroxypropyl methyl cellulose; partially saponified polyvinyl alcohol, acrylic acid polymers; and water-soluble polymers such as gelatin. The above-mentioned dispersion aids may be used alone or in combination of two or more. The dispersion aid is added, for example, in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the monomers to be charged.

[0105] Also, as for the polymerization initiator to be used, those conventionally used in the polymerization of vinyl chloride may be used. Examples of the above polymerization initiators include percarbonate compounds such as diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethyl peroxydicarbonate; perester compounds such as α-cumyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, hexyl peroxyneodecanoate, and octyl peroxyneodecanoate; peroxides such as acetylcyclohexylsulfonyl peroxide and 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate; and azo compounds such as azobis-2,4-dimethylvaleronitrile and azobis(4-methoxy-2,4-dimethylvaleronitrile). The above polymerization initiators may be used alone or in combination of two or more. The polymerization initiator may be added, for example, in an amount of 0.01 to 3 parts by mass per 100 parts by mass of the monomer, and preferably in an amount of 0.05 to 3 parts by mass per 100 parts by mass of the monomer.

[0106] Furthermore, if necessary, a polymerization regulator, a chain transfer agent, a pH adjuster, a buffer, a gelation improver, an antistatic agent, a scale inhibitor, etc., which are appropriately used in the polymerization of vinyl chloride, can be added. Regarding the reduced viscosity (K value) of the vinyl chloride polymer obtained in the present invention, a polymer within a desired range can be obtained by using the apparatus of the present invention, and preferably a polymer within the range of 40 to 90 can be obtained.

[0107] Examples of the pH adjuster or buffer include citric acid, trisodium citrate, diammonium citrate, triammonium citrate, potassium hydrogen phthalate, sodium nitrate, sodium carbonate, potassium carbonate, cesium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, barium hydroxide, disodium phosphate, dipotassium phosphate, and tripotassium phosphate. The above pH adjuster or buffer may be used alone or in combination of two or more.

[0108] The overlapping device 100 may be an example of a reaction device. The reaction vessel 110 may be an example of a reactor. The inner surface of the reaction vessel 110 may be an example of the inner wall surface of the reactor. The side surface of the reaction vessel 110 may be an example of the inner wall surface of the reactor. The flow path of the heat medium arranged in the main body 132 of the baffle 130 may be an example of the second cooling pipe. The support 134 of the baffle 130 may be an example of at least a part of the baffle. The serpentine cooling pipe 140 may be an example of the first cooling pipe. The serpentine cooling pipe 150 may be an example of the first cooling pipe. One of the serpentine cooling pipes 140 and one of the serpentine cooling pipes 150 may be an example of at least two of the plurality of first cooling pipes. The flow path 172 may be an example of the third cooling pipe. The flow path 182 may be an example of the third cooling pipe.

[0109] Figure 2 schematically shows an example of the internal structure arranged inside the reaction vessel 110. In Figure 2, for the purpose of simplifying the explanation, the depiction of the stirrer 120 is omitted. As shown in Figure 2, the overlapping device 100 includes, as one or more baffles 130, a baffle 232, a baffle 234, a baffle 236, and a baffle 238. Further, the overlapping device 100 includes, as one or more serpentine cooling pipes 140, a serpentine cooling pipe 242, a serpentine cooling pipe 244, a serpentine cooling pipe 246, and a serpentine cooling pipe 248. Similarly, the overlapping device 100 includes, as one or more serpentine cooling pipes 150, a serpentine cooling pipe 252, a serpentine cooling pipe 254, a serpentine cooling pipe 256, and a serpentine cooling pipe 258.

[0110] Figure 3 shows a schematic cross-sectional view of an example of the reaction vessel 110. In Figure 3, for the purpose of simplifying the explanation, the depiction of the serpentine cooling pipe 140 is omitted. Also, for the purpose of simplifying the explanation, the installation positions of the baffle 232, the baffle 234, the baffle 236, and the baffle 238 are deformed.

[0111] As shown in FIG. 3, in the present embodiment, the reaction vessel 110 includes a straight cylindrical portion 312, a first mirror plate 314, a second mirror plate 316, and a pedestal 318. In the present embodiment, the straight cylindrical portion 312 has a cylindrical shape. When the length of the straight cylindrical portion 312 in the extending direction (the z direction in the figure) is L and the inner diameter of the straight cylindrical portion 312 is D, the straight cylindrical portion 312 is designed such that, for example, the value of L / D is 1.0 to 3.0. The straight cylindrical portion 312 may be designed such that the value of L / D is 1.5 to 2.5.

[0112] In the present embodiment, the first mirror plate 314 is coupled to one end of the straight cylindrical portion 312 and constitutes the bottom plate of the reaction vessel 110. In the present embodiment, the second mirror plate 316 is coupled to the other end of the straight cylindrical portion 312 and constitutes the top plate of the reaction vessel 110. In the present embodiment, the pedestal 318 holds the power mechanism 126.

[0113] Also, as shown in FIG. 3, around the polymerization apparatus 100, there are arranged a refrigerant supply pipe 332 for supplying refrigerant from a refrigerant supply source to the reaction vessel 110, and a refrigerant return pipe 334 for returning the heat-exchanged refrigerant from the reaction vessel 110 to the refrigerant supply source. Further, according to the embodiment shown in FIG. 3, the baffle 232 and the baffle 234 are connected by a connecting portion 342, and the refrigerant flowing out from the baffle 232 is configured to be able to flow into the baffle 234. Also, the baffle 234 and the baffle 236 are connected by a connecting portion 344, and the refrigerant flowing out from the baffle 234 is configured to be able to flow into the baffle 236. Similarly, the baffle 236 and the baffle 238 are connected by a connecting portion 346, and the refrigerant flowing out from the baffle 236 is configured to be able to flow into the baffle 238. Details of each baffle will be described later.

[0114] According to the present embodiment, the refrigerant supplied from the refrigerant supply pipe 332 to the reaction vessel 110 flows into the baffle 232, passes through the baffle 234, the baffle 236, and the baffle 238, and is discharged to the refrigerant return pipe 334. Note that the refrigerant flow method is not limited to the present embodiment.

[0115] For example, in other embodiments, the refrigerant supplied from the refrigerant supply pipe 332 to the reaction vessel 110 flows into the baffle 232, passes through the baffle 234, and is discharged into the refrigerant return pipe 334. Further, the refrigerant supplied from the refrigerant supply pipe 332 to the reaction vessel 110 flows into the baffle 238, passes through the baffle 236, and is discharged into the refrigerant return pipe 334. In still other embodiments, each of the baffle 232, the baffle 234, the baffle 236, and the baffle 238 is configured to be able to independently control the flow rate of the refrigerant supplied to each baffle.

[0116] FIG. 4 shows a schematic plan view of an example of the reaction vessel 110. In the present embodiment, (i) the baffle 232, the baffle 234, the baffle 236, and the baffle 238, (ii) the serpentine cooling pipes 242, 244, 246, and 248, and (iii) the serpentine cooling pipes 252, 254, 256, and 258 are arranged concentrically.

[0117] In the present embodiment, the serpentine cooling pipes 242, 244, 246, and 248 are arranged on substantially the same circumference. Further, in the present embodiment, (i) the baffle 232, the baffle 234, the baffle 236, and the baffle 238, and (ii) the serpentine cooling pipes 252, 254, 256, and 258 are arranged on substantially the same circumference.

[0118] That is, in the cross section at a specific position of the straight body portion 312, the centers of the cross sections of the baffle 232, the baffle 234, the baffle 236, and the baffle 238 and the centers of the cross sections of the serpentine cooling pipes 252, 254, 256, and 258 are arranged on substantially the same circumference. The cross section at a specific position of the straight body portion 312 is a plane (in the xy plane in the figure) perpendicular to the extending direction of the straight body portion 312 (in the z direction in the figure), passes through the centers of the serpentine cooling pipes 252, 254, 256, and 258, and may be a cross section obtained by cutting the reaction vessel 110. In this case, the width of each pipe in the cross section coincides with the diameter of each pipe.

[0119] In this embodiment, the baffles 232, 234, 236, and 238 are arranged at positions that are substantially symmetric around the central axis of the reaction vessel 110. The serpentine cooling pipes 242, 244, 246, and 248 are arranged at positions that are substantially symmetric around the central axis of the reaction vessel 110. The serpentine cooling pipes 252, 254, 256, and 258 are arranged at positions that are substantially symmetric around the central axis of the reaction vessel 110.

[0120] As shown in FIG. 4, the serpentine cooling pipe 252 is arranged at a position between the baffle 232 and the baffle 234. The serpentine cooling pipe 254 is arranged at a position between the baffle 234 and the baffle 236. The serpentine cooling pipe 256 is arranged at a position between the baffle 236 and the baffle 238. The serpentine cooling pipe 258 is arranged at a position between the baffle 238 and the baffle 232. The outer diameters of the serpentine cooling pipes 252, 254, 256, and 258 may be smaller than the width Bw of the baffles 232, 234, 236, and 238.

[0121] In this embodiment, the diameter of the circle in which the serpentine cooling pipes 242, 244, 246, and 248 are arranged is smaller than the diameter of the circle in which the serpentine cooling pipes 252, 254, 256, and 258 are arranged. According to this embodiment, in the diameter direction of the straight body portion 312 of the reaction vessel 110, the serpentine cooling pipes can be arranged in multiple stages. Thereby, for example, compared with the case where a large ring-shaped or spiral pipe is arranged inside the reaction vessel 110, the degree of freedom in arranging the internal structures is improved. As a result, a polymerization apparatus 100 having excellent cooling efficiency can be manufactured.

[0122] The diameter D of the virtual circle on which the outer circumferences of the serpentine cooling pipes 242, 244, 246, and 248 are arranged c is not particularly limited, but is preferably larger than the diameter D of the rotation region of the stirring blade 124. D d / D c ​d is preferably 1.1 or more, and more preferably 1.2 or more.

[0123] In this embodiment, the distances between each of the meandering cooling pipes 252, 254, 256, and 258 and the inner surface of the straight body portion 312 are all P C1 Likewise, the distances between each of the meandering cooling pipes 242, 244, 246, and 248 and the inner surface of the straight body portion 312 are all P C2 As shown in FIG. 4, in this embodiment, P C2 >P C1 is.

[0124] The above-mentioned P C1 and P C2 are not particularly limited, but P C1 is preferably set such that the distance between the outer periphery of each meandering cooling pipe and the inner surface of the straight body portion 312 is 40 mm or more. Note that P C1 may be set to be 40 mm or more. When the above distance or P C1 is less than 40 mm, polymer scale may easily adhere between the inner wall surface of the reaction vessel 110 and the meandering cooling pipe 150 in the vicinity of the gas-liquid interface inside the reaction vessel 110.

[0125] Similarly, the distance P C between the meandering cooling pipe 242 and the meandering cooling pipe 252 is preferably 40 mm or more. The distance Pc is determined, for example, by calculating the minimum value of the distance between the outer peripheries of the meandering cooling pipe 242 and the meandering cooling pipe 252 in the above cross section. When P C is less than 40 mm, polymer scale may easily adhere.

[0126] The distance between a specific serpentine cooling pipe and the inner surface of the straight body portion 312 may be determined as the shortest distance between the two in a cross-section perpendicular to the extending direction of the straight body portion 312 and passing through the center of the specific serpentine cooling pipe. The distance between each serpentine cooling pipe and the inner surface of the straight body portion 312 is determined, for example, by calculating the minimum value of the distance between the center line along the extending direction of each serpentine cooling pipe and the inner surface of the straight body portion 312 in the above-mentioned cross-section. In this embodiment, the center line along the extending direction of each of the above serpentine cooling pipes is curved in an arc shape. Details of the above distance will be described later.

[0127] As shown in FIG. 4, in the cross-section at a specific position of the straight body portion 312, the cross-sections of the serpentine cooling pipes 242, 244, 246, and 254 have an arc shape. Similarly, the cross-sections of the serpentine cooling pipes 252, 254, 256, and 258 have an arc shape. The shapes of the cross-sections of the serpentine cooling pipes 242, 244, 246, and 254 and the shapes of the cross-sections of the serpentine cooling pipes 252, 254, 256, and 258 may be similar. For example, when the cross-sections of the serpentine cooling pipes 242 and 252 have an arc shape, the central angle of the arc of the serpentine cooling pipe 242 and the central angle of the arc of the serpentine cooling pipe 252 may be substantially the same. The same may apply to the serpentine cooling pipes 244 and 254, the serpentine cooling pipes 246 and 256, and the serpentine cooling pipes 248 and 258.

[0128] When the shape of the above serpentine cooling pipe is on an arc, the magnitude of the central angle of the arc may be 270 degrees or less. The magnitude of the central angle of the arc may also be 240 degrees or less, 210 degrees or less, 180 degrees or less, 150 degrees or less, 120 degrees or less, 90 degrees or less, or 60 degrees or less.

[0129] Also, in the present embodiment, the length in the extending direction of at least one of the meandering cooling pipes 252, 254, 256, and 258 (which is the length of the arc in the figure) is smaller than 2 / 3 of the length of the inner circumference of the straight body portion 312. The above-mentioned length in the extending direction (which is the length of the arc in the figure) may be 1 / 2 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 2 of the length of the inner circumference of the straight body portion 312, may be 1 / 3 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 3 of the length of the inner circumference of the straight body portion 312, may be 1 / 4 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 4 of the length of the inner circumference of the straight body portion 312, may be 1 / 6 or less of the length of the inner circumference of the straight body portion 312, or may be smaller than 1 / 6 of the length of the inner circumference of the straight body portion 312.

[0130] As described above, the coiled cooling pipe described in Japanese Patent Application Laid-Open No. 7-233206 has a substantially circular shape. That is, the central angle of the arc of the cooling pipe is approximately 360 degrees. Therefore, the baffle and the coiled cooling pipe cannot be arranged on substantially the same circumference. In contrast, according to the present embodiment, at least one of the one or more meandering cooling pipes 150 arranged closer to the inside of the straight body portion 312 than the meandering cooling pipe 140 has the above-described configuration, so that it can be arranged between the two baffles 130. Thereby, while reducing the influence of the meandering cooling pipe 150 on the mixing performance of the polymerization apparatus 100, the heat transfer area of the entire apparatus can be increased.

[0131] The inner surface of the straight body portion 312 may be an example of the inner wall surface of the reactor. The meandering cooling pipe 252 may be an example of the first cooling pipe with the smallest distance from the inner wall surface of the reactor. The meandering cooling pipe 254 may be an example of the first cooling pipe with the smallest distance from the inner wall surface of the reactor. The meandering cooling pipe 256 may be an example of the first cooling pipe with the smallest distance from the inner wall surface of the reactor. The meandering cooling pipe 258 may be an example of the first cooling pipe with the smallest distance from the inner wall surface of the reactor.

[0132] (Example of Another Embodiment) In this embodiment, an example of the polymerization apparatus 100 has been described by taking as an example the case where the serpentine cooling pipes are multiplexed in a double layer outward from the center of the straight barrel portion 312. However, the polymerization apparatus 100 is not limited to this embodiment. In other embodiments, the serpentine cooling pipes may be multiplexed in three or more layers outward from the center of the straight barrel portion 312. It is preferable that the serpentine cooling pipes are multiplexed in two to five layers outward from the center of the straight barrel portion 312.

[0133] FIG. 5 schematically shows an example of the internal structure of the baffle 232. Note that the baffles 234, 236, and 238 may also have the same internal structure as the baffle 232. In this embodiment, the baffle 232 has a double pipe structure including an inner pipe 510 and an outer pipe 520. The baffle 232 has an inlet 512 for allowing a refrigerant to flow into the inner pipe 510 and an outlet 522 for allowing the refrigerant to flow out from the inside of the outer pipe 520.

[0134] In this embodiment, the inlet 512 of the baffle 232 is connected to the refrigerant supply pipe 332 via the pipe 532 and the flow rate adjustment valve 542. Thereby, by adjusting the opening degree of the flow rate adjustment valve 542, the flow rate of the refrigerant flowing into the baffle 232 is adjusted. Similarly, the inlet 512 of the baffle 234 is connected to the refrigerant supply pipe 332 via the pipe 534 and the flow rate adjustment valve 544.

[0135] In this embodiment, the outlet 522 of the baffle 232 is connected to the refrigerant return pipe 334 and the baffle 234 via the connecting portion 342. As shown in FIG. 5, in this embodiment, the connecting portion 342 has a pipe 552, a flow rate adjustment valve 554, a pipe 556, and a flow rate adjustment valve 558.

[0136] The pipe 552 connects the outlet 522 and the refrigerant return pipe 334. The flow rate adjustment valve 554 is arranged in the middle of the pipe 552 to adjust the flow rate of the refrigerant flowing through the pipe 552. The pipe 556 connects the outlet 522 and the baffle 234. More specifically, the pipe 556 connects a position on the pipe 552 between the flow rate adjustment valve 554 and the outlet 522 of the baffle 232, and a position on the pipe 534 between the flow rate adjustment valve 544 and the inlet 512 of the baffle 234. The flow rate adjustment valve 558 is arranged in the middle of the pipe 556 to adjust the flow rate of the refrigerant flowing through the pipe 556.

[0137] (An example of another embodiment) In this embodiment, an example of the polymerization apparatus 100 has been described by taking as an example the case where the baffle 232 has a double-tube structure, the refrigerant flowing in from below the baffle 232 flows out from below the baffle 232, and flows into the baffle 234 from below the baffle 234. However, the polymerization apparatus 100 is not limited to this embodiment.

[0138] In other embodiments, the pipes may be configured such that the refrigerant flowing in from below the baffle 232 flows out from above the baffle 232 and flows into the baffle 234 from above the baffle 234. In still other embodiments, the baffle 232 may be a single tube.

[0139] FIG. 6 schematically shows an example of the structure of the serpentine cooling pipe 252. Note that the other serpentine cooling pipes 140 and 150 may also have the same structure as the serpentine cooling pipe 252. As shown in FIG. 6, the serpentine cooling pipe 252 extends in the z direction while repeatedly bending. In this embodiment, the serpentine cooling pipe 252 has a serpentine portion 610. The serpentine portion 610 has a plurality of extending portions 612 and one or more bending portions 614.

[0140] In the serpentine cooling pipe 252 described in relation to FIG. 6, the serpentine portion 610 has 15 extending portions 612 and 14 bending portions 614. The number of extending portions 612 in a single serpentine portion 610 may be referred to as the number of stages. As shown in FIG. 2, in the present embodiment, the serpentine cooling pipe 252 extends on the xy plane at the extending portions 612 and bends in the z direction at the bending portions 614.

[0141] In the present embodiment, each of the plurality of extending portions 612 extends on substantially the same plane. For example, even when the extending portions 612 are designed to extend on the same plane, due to errors associated with manufacturing, installation, etc., the extending portions 612 may not completely extend on the same plane. In such a case, the extending portions 612 may be regarded as extending on substantially the same plane. It should be noted that when the extending portions 612 extend on substantially the same plane, it is not limited to the above example.

[0142] In this regard, the serpentine cooling pipe 252 is different from a spiral cooling pipe. By the serpentine cooling pipe 252 extending in a serpentine manner, the surface area per installation area can be larger compared to the case where the cooling pipe extends in a spiral shape.

[0143] As described in relation to FIG. 4, in the present embodiment, each of the plurality of extending portions 612 extends while curving on the xy plane. The length P in the extending direction of each of the plurality of extending portions 612 L may be the same, or the lengths in the extending directions of at least two extending portions 612 may be different. In the present embodiment, P L is the length of the extending portion 612 on the xy plane. P L may be the length of the extending portion 612 in the xy plane passing through the center of the cross-section of the extending portion 612 when the extending portion 612 is cut by a plane substantially perpendicular to the extending direction of the extending portion 612 (in this case, a plane substantially parallel to the z direction).

[0144] As described above, P Lmay be smaller than 2 / 3 of the length of the inner circumference of the straight body portion 312. In this regard, the meandering cooling pipe 252 is different from the coiled cooling pipe described in Japanese Patent Application Laid-Open No. 7-233206.

[0145] In a single meandering portion 610, among a plurality of extending portions 612, P of more than 1 / 2 of the number of extending portions 612 L may be smaller than 2 / 3 of the length of the inner circumference of the straight body portion 312. The above P L may be 1 / 2 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 2 of the length of the inner circumference of the straight body portion 312, may be 1 / 3 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 3 of the length of the inner circumference of the straight body portion 312, may be 1 / 4 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 4 of the length of the inner circumference of the straight body portion 312, may be 1 / 6 or less of the length of the inner circumference of the straight body portion 312, and may be smaller than 1 / 6 of the length of the inner circumference of the straight body portion 312.

[0146] Among a plurality of extending portions 612, P of more than 2 / 3 of the number of extending portions 612 L may be smaller than 2 / 3 of the length of the inner circumference of the straight body portion 312. The above P L may be 1 / 2 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 2 of the length of the inner circumference of the straight body portion 312, may be 1 / 3 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 3 of the length of the inner circumference of the straight body portion 312, may be 1 / 4 or less of the length of the inner circumference of the straight body portion 312, may be smaller than 1 / 4 of the length of the inner circumference of the straight body portion 312, may be 1 / 6 or less of the length of the inner circumference of the straight body portion 312, and may be smaller than 1 / 6 of the length of the inner circumference of the straight body portion 312.

[0147] In one embodiment, at least one of the plurality of extending portions 612 extends while curving on a substantially the same plane. For example, at least one of the plurality of extending portions 612 extends along an arc or an elliptical arc virtually arranged on the xy plane. In other embodiments, at least one of the plurality of extending portions 612 extends linearly on a substantially the same plane.

[0148] In this embodiment, two of the plurality of extending portions 612 extend on two substantially parallel planes. For example, two adjacent extending portions 612 extend on two substantially parallel planes. Thereby, a meandering portion 610 extending in a ladder shape is obtained. In other embodiments, two of the plurality of extending portions 612 may extend on two non-parallel planes. For example, two adjacent extending portions 612 extend on two intersecting planes. Thereby, a meandering portion 610 extending in a zigzag shape is obtained.

[0149] In this embodiment, each of the one or more bending portions 614 connects the ends of two adjacent extending portions 612. In the embodiment shown in FIG. 6, each of the one or more bending portions 614 includes a portion bent in the z direction. Thereby, the meandering portion 610 extends in the z direction while bending. The shape of the bending portion 614 is not particularly limited. The shape of a cross section (sometimes referred to as a longitudinal section) obtained by cutting the bending portion 614 with a plane parallel to the extending direction of the meandering cooling pipe 252 and passing through the center of the bending portion 614 may have a continuously bent shape or a shape composed of a plurality of straight lines. Examples of the continuously bent shape include an arc shape or an elliptical arc shape. The bending portion 614 may be composed of a portion having a continuously bent shape and a portion having a shape composed of one or more straight lines.

[0150] The diameter of the flow path of the meandering cooling pipe 252 is not particularly limited, but the above diameter is preferably 10 to 200 mm. The number of extending portions 612 (sometimes referred to as the number of stages) included in a single meandering cooling pipe 252 is not particularly limited, but the above number of stages is preferably 2 to 70. The size of the distance (sometimes referred to as the pitch) Pp between two adjacent extending portions 612 is not particularly limited, but the above Pp is preferably 60 mm or more. When Pp is less than 60 mm, polymer scale may easily adhere.

[0151] (An example of another embodiment) In this embodiment, an example of the serpentine cooling pipe 252 has been described by taking the case where the serpentine cooling pipe 252 extends in the z direction while bending. However, the serpentine cooling pipe 252 is not limited to this embodiment. In other embodiments, the serpentine cooling pipe 252 may extend in the x direction or the y direction while bending.

[0152] In this embodiment, an example of the serpentine cooling pipe 252 has been described by taking the case where the extending portion 612 extends on the xy plane and the bending portion 614 bends in the z direction. However, the serpentine cooling pipe 252 is not limited to this embodiment. In other embodiments, the bending portion 614 may include a first bending member that bends on the xy plane and a second bending member that bends in the z direction.

[0153] FIG. 7 schematically shows another example of the structure of the serpentine cooling pipe 252. In this embodiment, the serpentine cooling pipe 252 extends in the z direction while bending in a zigzag shape. In this embodiment, the serpentine cooling pipe 252 includes a supply pipe 702, an outflow pipe 704, and a serpentine portion 710. In this embodiment, the serpentine portion 710 has a plurality of extending portions 712 and one or more bending portions 714.

[0154] The supply pipe 702 allows the refrigerant supplied to the serpentine portion 710 to flow through. The outflow pipe 704 allows the refrigerant flowing out from the serpentine portion 710 to flow through. The serpentine portion 710 extends in the z direction while repeatedly bending.

[0155] The serpentine cooling pipe 252 described in relation to FIG. 7 is different from the serpentine cooling pipe 252 described in relation to FIG. 6 in that the plurality of extending portions 712 are not arranged substantially parallel. Regarding features other than the above differences, the serpentine cooling pipe 252 described in relation to FIG. 7 may have the same configuration as the serpentine cooling pipe 252 described in relation to FIG. 6.

[0156] FIG. 8 schematically shows another example of the structure of the serpentine cooling pipe 252. In the present embodiment, the serpentine cooling pipe 252 includes a supply pipe 702, an outflow pipe 704, and a serpentine portion 810. In the present embodiment, the serpentine portion 810 has a serpentine portion 812, a connecting portion 822, a serpentine portion 814, a connecting portion 824, and a serpentine portion 816.

[0157] In the present embodiment, the serpentine portion 810 extends in the z direction while repeatedly bending. In the present embodiment, the serpentine portion 812 extends in the x direction while repeatedly bending. The serpentine portion 812 extends, for example, in the positive direction of the x direction. In the present embodiment, the connecting portion 822 connects the serpentine portion 812 and the serpentine portion 814. In the present embodiment, the serpentine portion 814 extends in the x direction while repeatedly bending. The serpentine portion 814 extends, for example, in the negative direction of the x direction. In the present embodiment, the connecting portion 824 connects the serpentine portion 814 and the serpentine portion 816. In the present embodiment, the serpentine portion 816 extends in the x direction while repeatedly bending. The serpentine portion 814 extends, for example, in the positive direction of the x direction.

[0158] Each of the serpentine portion 812, the serpentine portion 814, and the serpentine portion 816 may have the same configuration as the serpentine portion 610. For example, at least one of the serpentine portion 812, the serpentine portion 814, and the serpentine portion 816 has a plurality of extending portions and one or more bending portions. In this case, each of the plurality of extending portions may extend on the xy plane, on the xz plane, or on the yz plane.

[0159] FIG. 9 schematically shows an example of a main part of the polymerization apparatus 900. The polymerization apparatus 900 is different from the polymerization apparatus 100 in that the pitch Pp of the serpentine cooling pipe 140 and the pitch Pp of the serpentine cooling pipe 150 are different. Regarding features other than the above differences, the polymerization apparatus 900 may have the same configuration as the polymerization apparatus 100.

[0160] The pitch Pp of the serpentine cooling pipe 140 may be larger than the pitch Pp of the serpentine cooling pipe 150. For example, when the viscosity of the slurry flowing inside the reaction vessel 110 is relatively high, the flow of the slurry becomes slow. When the flow of the slurry becomes slow, scale is likely to adhere to the surfaces of the serpentine cooling pipe 140, the serpentine cooling pipe 150, the straight body portion 312, etc. An example of a case where the viscosity of the slurry is relatively high is the suspension polymerization of vinyl chloride. Even in such a case, since the serpentine cooling pipe 140 has a relatively large pitch Pp, the discharge flow generated by the stirring blade 124 reaches the serpentine cooling pipe 150 and the straight body portion 312 while having sufficient momentum. Thereby, the flow state in the vicinity of the serpentine cooling pipe 140, the serpentine cooling pipe 150, the straight body portion 312, etc. is improved, and the adhesion of scale is prevented.

[0161] (Example of another embodiment) In another embodiment, the pitch Pp of the serpentine cooling pipe 140 may be smaller than the pitch Pp of the serpentine cooling pipe 150.

[0162] FIG. 10 schematically shows an example of a main part of the polymerization apparatus 1000. The polymerization apparatus 1000 is different from the polymerization apparatus 100 in that the number of stages of the serpentine cooling pipe 140 and the number of stages of the serpentine cooling pipe 150 are different. The polymerization apparatus 1000 may have the same configuration as the polymerization apparatus 100 with respect to features other than the above differences. Further, within a range where there is no technical contradiction, the polymerization apparatus 1000 may have the features of various polymerization apparatuses according to other embodiments.

[0163] In one embodiment, the number of stages of the serpentine cooling pipe 140 and the serpentine cooling pipe 150 is adjusted such that the position of the upper end of the serpentine cooling pipe 140 is lower than the position of the upper end of the serpentine cooling pipe 150. For example, when the viscosity of the slurry flowing inside the reaction vessel 110 is relatively high, scale may adhere to the gas-liquid interface or foaming may easily occur. An example of a case where the viscosity of the slurry is relatively high is the suspension polymerization of vinyl chloride. When foaming at the gas-liquid interface becomes intense, heat removal by the reflux condenser 180 is restricted. Even in such a case, by suppressing the height of the upper end of the serpentine cooling pipe 140 arranged closer to the stirring blade 124, the flow at the gas-liquid interface becomes active, and adhesion and foaming of the slurry can be suppressed. It is preferable that the number of stages of the serpentine cooling pipe 140 is adjusted such that the position of the upper end of the serpentine cooling pipe 140 is lower than that of the stirring blade 124 arranged at the uppermost stage.

[0164] (An example of another embodiment) In other embodiments, the number of stages of the serpentine cooling pipe 140 and the serpentine cooling pipe 150 may be adjusted such that the position of the lower end of the serpentine cooling pipe 140 is higher than the position of the lower end of the serpentine cooling pipe 150. In still other embodiments, the number of stages of the serpentine cooling pipe 140 is adjusted so as not to interfere with the rotation of the stirring blade 124.

[0165] FIG. 11 schematically shows an example of the main part of the polymerization apparatus 1100. The polymerization apparatus 1100 is different from the polymerization apparatus 100 in that it includes a serpentine cooling pipe 1160 between the serpentine cooling pipe 140 and the serpentine cooling pipe 150. Regarding features other than the above differences, the polymerization apparatus 1100 may have the same configuration as the polymerization apparatus 100. Also, within a range where there is no technical contradiction, the polymerization apparatus 1100 may have features of various polymerization apparatuses according to other embodiments.

[0166] FIG. 12 schematically shows an example of a main part of the polymerization apparatus 1200. The polymerization apparatus 1200 is different from the polymerization apparatus 100 in that it includes a serpentine cooling pipe 1252 having a semicircular cross section instead of the serpentine cooling pipes 252, 256, and 258. Regarding features other than the above differences, the polymerization apparatus 1200 may have the same configuration as the polymerization apparatus 100. Also, within a technically non - contradictory range, the polymerization apparatus 1200 may have features of various polymerization apparatuses according to other embodiments.

[0167] FIG. 13 schematically shows an example of a main part of the polymerization apparatus 1300. The polymerization apparatus 1300 is different from the polymerization apparatus 100 in that it includes serpentine cooling pipes 1351, 1352, 1353, 1354, 1355, and 1356 including a linearly extending extension part 612 instead of the serpentine cooling pipes 252, 254, 256, and 258 including a curved and extending extension part 612. Also, the polymerization apparatus 1300 is different from the polymerization apparatus 100 in that it includes baffles 1331, 1332, 1333, 1334, 1335, and 1336. Regarding features other than the above differences, the polymerization apparatus 1300 may have the same configuration as the polymerization apparatus 100. Also, within a technically non - contradictory range, the polymerization apparatus 1300 may have features of various polymerization apparatuses according to other embodiments.

[0168] In the present embodiment, the serpentine cooling pipes 1351, 1352, 1353, 1354, 1355, and 1355 are arranged at positions substantially symmetric around the central axis of the reaction vessel 110 on the sides of a virtual regular hexagon. Also, the baffles 1331, 1332, 1333, 1334, 1335, and 1336 are arranged at the vertices of the above - mentioned virtual regular hexagon.

[0169] According to this embodiment, the number of the meandering cooling pipes 140 is different from the number of the meandering cooling pipes 150. For example, the number of the meandering cooling pipes 140 is smaller than the number of the meandering cooling pipes 150. According to this embodiment, the shapes of the meandering cooling pipe 140 and the meandering cooling pipe 150 are not similar. For example, the extending portion 612 of the meandering cooling pipe 140 extends in a curved manner, and the extending portion 612 of the meandering cooling pipe 150 extends linearly.

[0170] (An example of another embodiment) In this embodiment, an example of the polymerization apparatus 1300 has been described by taking as an example the case where the baffles 1331, 1332, 1333, 1334, 1335, and 1336 are arranged at the vertices of a virtual regular hexagon. However, the polymerization apparatus 1300 is not limited to this embodiment.

[0171] In other embodiments, at least one of the baffles 1331, 1332, 1333, 1334, 1335, and 1336 may be arranged between the above regular hexagon and the straight body portion 312. In still other embodiments, at least one of the baffles 1331, 1332, 1333, 1334, 1335, and 1336 may be arranged between the above regular hexagon and a virtual circle in which the meandering cooling pipes 242, 244, 246, and 248 are arranged.

[0172] According to this embodiment, an example of the polymerization apparatus 1300 has been described by taking as an example the case where the number of the meandering cooling pipes 140 is smaller than the number of the meandering cooling pipes 150. However, the polymerization apparatus 1300 is not limited to this embodiment. In other embodiments, the number of the meandering cooling pipes 140 may be larger than the number of the meandering cooling pipes 150.

[0173] According to this embodiment, an example of the polymerization apparatus 1300 has been described by taking as an example the case where the extending portion 612 of the meandering cooling pipe 140 extends in a curved manner and the extending portion 612 of the meandering cooling pipe 150 extends linearly. However, the polymerization apparatus 1300 is not limited to this embodiment. In other embodiments, the extending portion 612 of the meandering cooling pipe 140 may extend linearly, and the extending portion 612 of the meandering cooling pipe 150 may extend in a curved manner.

[0174] (An example of another embodiment) In this embodiment, an example of the polymerization apparatus 1300 has been described by taking as an example the case where the diameter of the virtual circle 1403 is larger than the diameter of the virtual circle 1404 and smaller than the diameter of the virtual circle 1405. However, the polymerization apparatus 1300 is not limited to this embodiment. In other embodiments, the diameter of the virtual circle 1403 may be smaller than the diameter of the virtual circle 1404. In still other embodiments, the diameter of the virtual circle 1403 may be larger than the diameter of the virtual circle 1405.

[0175] FIG. 14 schematically shows an example of a main part of the polymerization apparatus 1400. The polymerization apparatus 1400 is different from the polymerization apparatus 100 in that the virtual circle 1403 in which the baffles 232, 234, 236, and 238 are arranged is disposed between the virtual circle 1404 in which the meandering cooling pipes 242, 244, 246, and 248 are arranged and the virtual circle 1405 in which the meandering cooling pipes 252, 254, 256, and 258 are arranged. Regarding features other than the above differences, the polymerization apparatus 1400 may have the same configuration as the polymerization apparatus 100. Also, within a technically non - conflicting range, the polymerization apparatus 1400 may have features of various polymerization apparatuses according to other embodiments.

[0176] FIG. 15 schematically shows an example of the main part of the polymerization apparatus 1500. The polymerization apparatus 1500 is different from the polymerization apparatus 1400 in that the baffle 232 is disposed between the serpentine cooling pipes 242 and 252, the baffle 234 is disposed between the serpentine cooling pipes 244 and 254, the baffle 236 is disposed between the serpentine cooling pipes 246 and 256, and the baffle 238 is disposed between the serpentine cooling pipes 248 and 258. Regarding features other than the above differences, the polymerization apparatus 1500 may have the same configuration as the polymerization apparatus 1400. Also, within a technically non - conflicting range, the polymerization apparatus 1500 may have features of various polymerization apparatuses according to other embodiments.

[0177] FIG. 16 schematically shows an example of the main part of the polymerization apparatus 1600. The polymerization apparatus 1600 is different from the polymerization apparatus 100 in that it does not include the serpentine cooling pipes 244 and 248. Regarding features other than the above differences, the polymerization apparatus 1600 may have the same configuration as the polymerization apparatus 100. Also, within a technically non - conflicting range, the polymerization apparatus 1600 may have features of various polymerization apparatuses according to other embodiments.

[0178] For example, when the viscosity of the slurry flowing inside the reaction vessel 110 is relatively high, if the serpentine cooling pipes 140 and 150 are arranged in multiple stages in the radial direction of the straight body portion 312, the slurry may stagnate in the region between the serpentine cooling pipes 140 and 150. An example of a case where the viscosity of the slurry is relatively high is the suspension polymerization of vinyl chloride. Even in such a case, by changing the number of radial stages of the serpentine cooling pipes 140 and 150 along the circumferential direction of the straight body portion 312, the stagnation of the slurry is suppressed. As a result, the mixing of the slurry is promoted.

[0179] FIG. 17 schematically shows an example of the main part of the polymerization system 1700. In the present embodiment, the polymerization system 1700 includes a polymerization apparatus 100 and a controller 1710. Further, in the present embodiment, the polymerization system 1700 includes a stirring system 1702. The stirring system 1702 has a stirring shaft 122, stirring blades 1722, stirring blades 1724, stirring blades 1726, and a power mechanism 126. The polymerization apparatus 100 described in relation to FIG. 17 may have the same configuration as the polymerization apparatus 100 described in relation to FIG. 1, except that it includes stirring blades 1722, stirring blades 1724, and stirring blades 1726 instead of the plurality of stirring blades 124.

[0180] In the present embodiment, for the purpose of simplicity of explanation, an example of the polymerization system 1700 and the stirring system 1702 is described by taking the case where three stirring blades, namely, the stirring blade 1722, the stirring blade 1724, and the stirring blade 1726, are attached to the stirring shaft 122 as an example. However, the polymerization system 1700 and the stirring system 1702 are not limited to the present embodiment. In other embodiments, two stirring blades are attached to the stirring shaft 122 of the polymerization system 1700 and the stirring system 1702. In still other embodiments, in other embodiments, four or more stirring blades are attached to the stirring shaft 122 of the polymerization system 1700 and the stirring system 1702.

[0181] As described above, the stirring shaft 122 is rotatably arranged inside the reaction vessel 110. In particular, a part of the stirring shaft 122 is arranged inside the straight body portion 312 of the reaction vessel 110 and is configured to be rotatable. The stirring shaft 122 is attached to the reaction vessel 110 such that the extending direction of the stirring shaft 122 substantially coincides with the extending direction of the straight body portion 312.

[0182] In the present embodiment, the three stirring blades, namely the stirring blade 1722, the stirring blade 1724, and the stirring blade 1726, are attached at different positions in the extending direction of the stirring shaft 122. The stirring blade 1722 is attached at the uppermost position among the plurality of stirring blades. The stirring blade 1724 is disposed between the stirring blade 1722 and the stirring blade 1726. The stirring blade 1726 is attached at the lowermost position among the plurality of stirring blades.

[0183] In the present embodiment, the stirring system 1702 stirs the liquid accommodated inside the reaction vessel 110 of the polymerization apparatus 100. Specifically, when the stirring shaft 122 rotates, the stirring blades 1722, 1724, and 1726 (which may sometimes be simply referred to as a plurality of stirring blades) attached to the stirring shaft 122 rotate, and as a result, the liquid accommodated inside the reaction vessel 110 is stirred.

[0184] In the present embodiment, the controller 1710 controls the rotation speed of the stirring shaft 122. The controller 1710 controls the rotation speed of the stirring shaft 122, for example, by controlling the output of the power mechanism 126. In the present embodiment, the controller 1710 controls the rotation speed of the stirring shaft 122 so that the rotation speed of the stirring shaft 122 satisfies the relationship shown in the following mathematical formula 1. (Mathematical formula 1) N(b / d)(L / D) / n ≦ 6.0

[0185] In mathematical formula 1, N represents the number of a plurality of stirring blades attached to the stirring shaft 122. As described above, in the present embodiment, N is 3. b represents the maximum value [m] of the blade widths of the plurality of stirring blades. That is, b represents the blade width of the stirring blade with the largest blade width among the stirring blades 1722, 1724, and 1726. d represents the maximum value [m] of the blade diameters of the plurality of stirring blades. That is, d represents the blade diameter of the stirring blade with the largest blade diameter among the stirring blades 1722, 1724, and 1726.

[0186] L represents the length [m] in the extending direction of the straight body portion 312 of the reaction vessel 110. D represents the maximum value [m] of the diameters of a plurality of inscribed circles that are substantially inscribed in the straight body portion 312 in each of the cross-sections formed by a plurality of planes that are planes substantially perpendicular to the extending direction of the straight body portion 312 (the vertical direction in the figure) and pass through the mounting positions of the respective stirring blades when the straight body portion 312 is cut by the plurality of planes. When the reaction vessel 110 has a cylindrical straight body portion 312, D is the inner diameter [m] of the straight body portion 312. n represents the set value of the rotational speed [rps] of the stirring shaft 122.

[0187] Thereby, generation of coarse particles can be suppressed. As a result, the particle size distribution of the polymer becomes narrow. In addition, generation of fish eyes can be suppressed. Further, adhesion of scale can be suppressed.

[0188] The parameter represented by N(b / d)(L / D) / n described above represents the degree of stirring of the liquid when a liquid of about the rated capacity of the reaction vessel 110 is accommodated inside the reaction vessel 110. Therefore, the above parameter may be referred to as a stirring parameter.

[0189] In the present embodiment, the internal volume of the reaction vessel 110 may be 40 to 300 m 3 Moreover, the ratio (L / D) of the length L in the extending direction of the straight body portion 312 to the diameter D of the inscribed circle of the straight body portion 312 of the reaction vessel 110 may be 1.0 to 3.0. Thereby, the effect that the dimension of the straight body portion 312 of the reaction vessel 110, the dimension of at least one of the plurality of stirring blades 124, and the set value of the rotational speed of the stirring shaft 122 are determined so as to satisfy the relationship shown in Formula 1 can be obtained more reliably.

[0190] The controller 1710 preferably controls the rotational speed of the stirring shaft 122 so that the rotational speed of the stirring shaft 122 satisfies the relationship shown in the following Formula 2. (Formula 2) 0.05 ≦ N(b / d)(L / D) / n ≦ 6.0

[0191] In Formula 2, the definitions of N, b, d, L, D, and n are the same as those in Formula 1. As a result, the generation of coarse particles is further suppressed. The particle size distribution of the polymer becomes even narrower. In addition, the occurrence of fish eyes is further suppressed. Moreover, the adhesion of scale is further suppressed.

[0192] When the polymerization apparatus 100 includes one or more meandering cooling pipes 140 or one or more meandering cooling pipes 150 (that is, when the number of series of meandering cooling pipes in the radial direction of the straight barrel portion 312 is 1 or more), it is preferable that the controller 1710 controls the rotational speed of the stirring shaft 122 so that the rotational speed of the stirring shaft 122 satisfies the relationship shown in the following Formula 3. (Formula 3) 0.15 ≦ N(b / d)(L / D) / n ≦ 5.5

[0193] In Formula 3, the definitions of N, b, d, L, D, and n are the same as those in Formula 1. As a result, the generation of coarse particles is further suppressed. The particle size distribution of the polymer becomes even narrower. In addition, the occurrence of fish eyes is further suppressed. Moreover, the adhesion of scale is further suppressed.

[0194] When a structure such as a cooling pipe is arranged inside the reaction vessel 110, it becomes difficult to control the flow state of the liquid accommodated inside the reaction vessel 110 as compared with the case where no structure is arranged inside the reaction vessel 110. In particular, the meandering cooling pipe 140 and the meandering cooling pipe 150 have a complex structure and can interfere with the stirring of the liquid in the extending direction of the straight barrel portion 312. Therefore, when the meandering cooling pipe 140 or the meandering cooling pipe 150 is arranged inside the reaction vessel 110, it becomes more difficult to control the stirring state of the liquid.

[0195] Therefore, when structures such as cooling pipes are arranged inside the reaction vessel 110, it is preferable to maintain the value of the stirring parameter within a narrower numerical range (i.e., 0.15 to 5.5) compared to the case where no structures are arranged inside the reaction vessel 110. Further, even when structures such as cooling pipes are arranged inside the reaction vessel 110, when the relationship shown by Formula 3 holds, polymers of the same quality as those produced when no structures such as cooling pipes are arranged inside the reaction vessel 110 can be produced.

[0196] In this case, the ratio of the maximum value of the distance Pp between two adjacent extending portions 612 to the length L in the extending direction of the straight cylindrical portion 312 may be 0.5 to 15%. The ratio of the minimum value P of the distance between one or more serpentine cooling pipes 140 or one or more serpentine cooling pipes 150 and the inner wall surface of the straight cylindrical portion 312 to the inner diameter D of the straight cylindrical portion 312 C1 may be 0.5 to 10%. The ratio of the maximum value P of the distance between one or more serpentine cooling pipes 140 or one or more serpentine cooling pipes 150 and the inner wall surface of the straight cylindrical portion 312 to the inner diameter D of the straight cylindrical portion 312 C2 may be 1 to 30%.

[0197] When the polymerization apparatus 100 includes one or more serpentine cooling pipes 140 and one or more serpentine cooling pipes 150 (that is, when the number of series of serpentine cooling pipes in the radial direction of the straight cylindrical portion 312 is 2 or more), the controller 1710 preferably controls the rotational speed of the stirring shaft 122 so that the rotational speed of the stirring shaft 122 satisfies the relationship shown by the following Formula 4. (Formula 4) 0.3 ≦ N(b / d)(L / D) / n ≦ 5.5

[0198] In Formula 4, the definitions of N, b, d, L, D, and n are the same as those in Formula 1. Thereby, the generation of coarse particles is further suppressed. The particle size distribution of the polymer becomes narrower. Further, the generation of fish eyes is further suppressed. In addition, the adhesion of scale is further suppressed. When the relationship shown by Formula 4 holds, in particular, the effect of suppressing the generation of fish eyes is particularly remarkable.

[0199] As described above, the meandering cooling pipes 140 and 150 have a complex structure and may interfere with the stirring of the liquid in the extending direction of the straight body portion 312. In particular, when the number of series of the meandering cooling pipes in the radial direction of the straight body portion 312 is 2 or more, the degree of the above interference becomes remarkable.

[0200] Therefore, when the number of series of the meandering cooling pipes in the radial direction of the straight body portion 312 is 2 or more, it is preferable to maintain the value of the stirring parameter within a narrower numerical range (that is, 0.3 to 5.5) as compared with the case where no structure is arranged inside the reaction vessel 110. Further, even when the number of series of the meandering cooling pipes in the radial direction of the straight body portion 312 is 2 or more, when the relationship represented by Equation 4 holds, a polymer of the same quality as that in the case where no structure such as a cooling pipe is arranged inside the reaction vessel 110 can be produced.

[0201] In this case, the ratio of the maximum value of the distance Pp between two adjacent extending portions 612 to the length L in the extending direction of the straight body portion 312 may be 0.5 to 15%. The ratio of the minimum value L1 of the distance between one or more meandering cooling pipes 140 or one or more meandering cooling pipes 150 and the inner wall surface of the straight body portion 312 to the inner diameter D of the straight body portion 312 may be 0.5 to 10%. The ratio of the maximum value L2 of the distance between one or more meandering cooling pipes 140 or one or more meandering cooling pipes 150 and the inner wall surface of the straight body portion 312 to the inner diameter D of the straight body portion 312 may be 1 to 30%.

[0202] The polymerization system 1700 may be an example of a reaction device. The stirring system 1702 may be an example of a stirring device. The controller 1710 may be an example of a control unit or a control device. The stirring blade 1722 may be an example of a first stirring blade. The stirring blade 1724 may be an example of a third stirring blade. The stirring blade 1726 may be an example of a second stirring blade. The power mechanism 126 may be an example of a driving unit.

[0203] FIG. 18 schematically shows an example of the attachment position of the stirring blades on the stirring shaft 122. In the present embodiment, taking as an example the case where the blade diameters of the stirring blades 1722, 1724, and 1726 are all di and the blade widths of the stirring blades 1722, 1724, and 1726 are all bi, an example of the attachment position of the stirring blades on the stirring shaft 122 will be described. Note that in other embodiments, at least two of the blade diameters of the stirring blades 1722, 1724, and 1726 may be different. Also, at least two of the blade widths of the stirring blades 1722, 1724, and 1726 may be different.

[0204] In FIG. 18, the dashed-dotted line 1820 indicates the rotation axis of the stirring shaft 122. The dashed-dotted line 1822 indicates the attachment position of the stirring blade 1722 on the stirring shaft 122. The dashed-dotted line 1824 indicates the attachment position of the stirring blade 1724 on the stirring shaft 122. The dashed-dotted line 1826 indicates the attachment position of the stirring blade 1726 on the stirring shaft 122.

[0205] In the present embodiment, the minimum value of the distance between the attachment positions of the plurality of stirring blades on the stirring shaft 122 and the position corresponding to one end of the straight body portion 312 on the stirring shaft 122 may be 0.1 to 0.45 times the length L in the extending direction of the straight body portion 312. For example, the distance Z between the attachment position of the stirring blade 1722 on the stirring shaft 122 and the position 1842 corresponding to the upper end 1832 of the straight body portion 312 on the stirring shaft 122 is set to be 0.1 to 0.45 times the length L in the extending direction of the straight body portion 312.

[0206] In the present embodiment, the stirring blade 1726 on the stirring shaft 122 is disposed between the first position 1852 and the second position 1854 of the stirring shaft 122. The attachment position of the stirring blade 1726 on the stirring shaft 122 may be the position of the midpoint of the blade width of the stirring blade 1726 on the stirring shaft 122. In FIG. 18, the attachment position of the stirring blade 1726 is represented as the intersection of the dashed-dotted line 1820 and the dashed-dotted line 1826.

[0207] When the stirring shaft 122 is attached to the straight cylindrical portion 312, the first position 1852 is located above the second position 1854. Also, the first position 1852 is located above the position 1844 corresponding to the lower end 1834 of the straight cylindrical portion 312 on the stirring shaft 122. The distance between the first position 1852 and the position 1844 corresponding to the lower end 1834 of the straight cylindrical portion 312 on the stirring shaft 122 may be 0.25 times or less of the inner diameter D of the straight cylindrical portion 312.

[0208] Also, when the stirring shaft 122 is attached to the straight cylindrical portion 312, the second position 1854 is located below the position 1844 corresponding to the lower end 1834 of the straight cylindrical portion 312 on the stirring shaft 122. The distance between the second position 1854 and the position 1844 corresponding to the lower end 1834 of the straight cylindrical portion 312 on the stirring shaft 122 may be 0.1 times or less of the inner diameter D of the straight cylindrical portion 312.

[0209] In the present embodiment, the stirring blade 1724 is attached near (N - 1) third positions obtained by equally dividing the space between the attachment position of the stirring blade 1722 and the attachment position of the stirring blade 1726 into (N - 1) parts. In the present embodiment, since N = 3, the stirring blade 1724 is attached at a position that bisects the space between the attachment position of the stirring blade 1722 and the attachment position of the stirring blade 1726. In this case, the distance C between the attachment position of the stirring blade 1722 and the attachment position of the stirring blade 1724 ia is substantially the same as the distance C between the attachment position of the stirring blade 1724 and the attachment position of the stirring blade 1726. ib

[0210] Note that the distance between the stirring blade 1724 and the above-described third position may be 0.5 times or less of the ratio (D / N) of the inner diameter D of the straight cylindrical portion 312 to the number N of the plurality of stirring blades. Also, when (N - 2) stirring blades 1724 are arranged between the stirring blade 1722 and the stirring blade 1726, the maximum value of the distance between the (N - 2) stirring blades 1724 and the corresponding third position may be 0.5 times or less of the ratio (D / N) of the inner diameter D of the straight cylindrical portion 312 to the number N of the plurality of stirring blades.

[0211] ​One stirring blade 1724 may be an example of (N - 2) third stirring blades. The attachment position of the stirring blade 1722 may be an example of the first attachment position. The attachment position of the stirring blade 1726 may be an example of the second attachment position.

Example

[0212] Hereinafter, examples are shown to specifically describe the present invention. Note that the present invention is not limited to the following examples.

[0213] (Polymerization conditions) In Examples 1 to 13 and Comparative Examples 1 to 5, using deionized water, vinyl chloride monomer, and commercially available reagents, the presence or absence of a serpentine cooling tube inside the reaction vessel, the arrangement of the serpentine cooling tube, the dimensions of the reaction vessel, and the rotation speed of the stirring shaft were changed to produce a vinyl chloride polymer. In Examples 1 to 13 and Comparative Examples 1 to 5, the polymerization temperature and the supply temperature of the refrigerant were made the same. Also, the above polymerization temperature was set based on the target value of the K value of the polymer.

[0214] (Evaluation) In each of Examples 1 to 10 and Comparative Example 1, the particle size distribution and the number of fish eyes of the produced polymer were measured. As the particle size distribution of the polymer, the mass percentage of the polymer particles passing through a 60 - mesh sieve, the mass percentage of the polymer particles passing through a 100 - mesh sieve, and the mass percentage of the polymer particles passing through a 200 - mesh sieve were measured.

[0215] The number of fish eyes was measured according to the following procedure. First, 100 parts by mass of a sample polymer, 50 parts by mass of bis(2 - ethylhexyl) phthalate (DOP), 2.0 parts by mass of a Ba / Zn - based stabilizer, 5.0 parts by mass of epoxidized soybean oil, 0.1 part by mass of carbon black, and 0.5 part by mass of titanium dioxide were mixed to obtain a compound. Next, 50 g of the above compound was kneaded with a roll mill at 145 °C for 6 minutes and separated as a sheet with a thickness of 0.3 mm. Then, the number of transparent particles in 100 cm 2 of the above sheet was visually measured to measure the number of fish eyes.

[0216] (Scale evaluation) Also, in each of Examples 1 to 10 and Comparative Example 1, the polymerization test was repeated. After the polymerization test for a predetermined number of times was completed, the surface of the inner wall surface of the reaction vessel was visually observed to confirm the presence or absence of scale adhesion. Further, when the serpentine cooling pipe 140 and / or the serpentine cooling pipe 150 was arranged inside the reaction vessel, the surface of the serpentine cooling pipe 140 and / or the serpentine cooling pipe 150 was visually observed to confirm the presence or absence of scale adhesion.

[0217] (Example 1) (Specifications of the polymerization apparatus 100) In Example 1, a vinyl chloride polymer was produced using the polymerization apparatus 100 shown in FIG. 2. In Example 1, a reaction vessel 110 with an internal volume of 80 m 3 was used. The diameter of the straight barrel portion 312 of the reaction vessel 110 was 3600 mm, and the length of the straight barrel portion 312 was 6800 mm. The ratio of the length L of the straight barrel portion 312 to the diameter D of the straight barrel portion 312 was 1.9.

[0218] Inside the reaction vessel 110, four serpentine cooling pipes 140 made of austenitic stainless steel cylindrical pipes with an outer diameter of 90 mm were arranged. The distance between the center of each of the four serpentine cooling pipes 140 and the central axis of the reaction vessel 110 was 1360 mm. Further, the four serpentine cooling pipes 140 were arranged at symmetric positions around the central axis of the reaction vessel 110. The number of stages of each of the four serpentine cooling pipes 140 was 12 stages. That is, each of the four serpentine cooling pipes 140 had 12 extending portions 612. In each of the four serpentine cooling pipes 140, the distance between adjacent extending portions 612 (sometimes referred to as the pitch Pp) was 400 mm.

[0219] The ratio of the distance P between the inner wall surface of the straight barrel portion 312 and the serpentine cooling pipe 140 to the diameter D of the straight barrel portion 312 C2 was 12.2%. The ratio of the pitch Pp to the length L of the straight barrel portion 312 was 5.9%.

[0220] Similarly, four serpentine cooling pipes 150 made of austenitic stainless steel cylindrical pipes with an outer diameter of 90 mm were installed inside the reaction vessel 110. The distance between the center of each of the four serpentine cooling pipes 150 and the central axis of the reaction vessel 110 was 1610 mm. Also, the four serpentine cooling pipes 150 were arranged at symmetric positions around the central axis of the reaction vessel 110. The number of stages of each of the four serpentine cooling pipes 150 was 12 stages. Also, in each of the four serpentine cooling pipes 150, the pitch Pp was 400 mm.

[0221] The ratio of the distance L1 between the inner wall surface of the straight barrel part 312 and the serpentine cooling pipe 150 to the diameter D of the straight barrel part 312 was 5.3%. The ratio of the pitch Pp to the length L of the straight barrel part 312 was 5.9%.

[0222] Next, a stirring shaft 122 with three paddle blades attached was installed in the reaction vessel 110. Also, the rotational speed of the stirring shaft 122 was determined so as to satisfy the relationship of the above-described formula (1). In Example 1, the value of the stirring parameter represented by N(b / d)(L / D) / n was 0.22. The stirring energy applied to the contents of the reaction vessel 110 was in the range of 80 to 200 kgf·m / s·m 3 within the range.

[0223] (Polymerization method) A vinyl chloride polymer was synthesized according to the following procedure. First, 32,900 kg of deionized water, 10.5 kg of partially saponified polyvinyl alcohol with a saponification degree of 80.0 mol%, and 4.5 kg of hydroxypropyl methylcellulose with a methoxy substitution degree of 28.5 mass% and a hydroxypropyl substitution degree of 8.9% were made into an aqueous solution and charged into the reaction vessel 110. Next, 30,100 kg of vinyl chloride monomer was charged into the reaction vessel 110. Thereafter, while stirring the mixed solution with the stirrer 120, polymerization initiator A, polymerization initiator B, and polymerization initiator C were press-fitted into the reaction vessel 110 with a pump.

[0224] As the polymerization initiator A, an isoparaffin solution containing di-2-ethylhexyl peroxydicarbonate was used. The addition amount of di-2-ethylhexyl peroxydicarbonate was 22.1 kg. As the polymerization initiator B, an isoparaffin solution containing t-butyl peroxyneodecanoate was used. The addition amount of t-butyl peroxyneodecanoate was 3.2 kg. As the polymerization initiator C, an isoparaffin solution containing cumyl peroxyneodecanoate was used. The addition amount of cumyl peroxyneodecanoate was 5.0 kg.

[0225] Next, hot water was passed through the jacket 170 to raise the temperature of the mixed solution inside the reaction vessel 110 to 57°C, thereby initiating the polymerization. Also, when the temperature of the mixed solution inside the reaction vessel 110 reached 57°C, the passage of cooling water through the baffle 130, the serpentine cooling pipe 140, the serpentine cooling pipe 150, and the jacket 170 was started. Then, when the polymerization conversion rate reached 20%, the reflux condenser 180 was operated.

[0226] Under the condition of maintaining the temperature of the mixed solution inside the reaction vessel 110 at 57°C, when the pressure inside the reaction vessel 110 decreased by 0.09 MPa compared to the average pressure after the start of polymerization, all cooling was stopped. 18 minutes after all cooling was stopped, an aqueous dispersion of triethylene glycol bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate] (concentration: 40% by mass) in an amount sufficient to stop the polymerization reaction was introduced into the reaction vessel 110. Thereby, the polymerization reaction was completed, and a vinyl chloride polymer was obtained.

[0227] After the polymerization reaction was completed, the particle size distribution of the synthesized vinyl chloride resin and the number of fish eyes were measured. Also, in order to confirm the scale adhesion situation, the above polymerization test was repeated with one batch as the above polymerization test. After a predetermined number of polymerization tests were completed, the scale adhesion situation inside the reaction vessel 110 was visually confirmed. The measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion situation are shown in Table 1.

[0228] (Examples 2 to 8) Using a polymerization apparatus similar to the polymerization apparatus 100 shown in FIG. 2, a vinyl chloride polymer was synthesized. In Examples 2 to 8, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the rotational speed of the stirring shaft 122, and the charged amount of the raw materials were different. In Examples 2 to 8, the stoichiometric ratio and reaction temperature of each raw material were adjusted in the same manner as in Example 1. Thus, based on the experimental results of Examples 1 to 8, the relationship between the set values of the dimensions of the reaction vessel, the dimensions of the stirring blades, and the rotational speed of the stirring shaft, and the quality of the produced polymer can be considered.

[0229] The outline of the specifications of the polymerization apparatuses of Examples 2 to 8 is shown in Table 1. Also, the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion status in Examples 2 to 8 are shown in Table 1.

[0230] (Example 9) Using a polymerization apparatus similar to the polymerization apparatus 100 shown in FIG. 2, except that it does not include the serpentine cooling pipe 140 and the serpentine cooling pipe 150, a vinyl chloride polymer was synthesized. In Example 9, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the presence or absence of the serpentine cooling pipe 140 and the serpentine cooling pipe 150, the rotational speed of the stirring shaft 122, and the charged amount of the raw materials were different. In Example 9, the stoichiometric ratio and reaction temperature of each raw material were adjusted in the same manner as in Example 1. Thus, the influence of the structures arranged inside the reaction vessel can be considered.

[0231] The outline of the specifications of the polymerization apparatus of Example 9 is shown in Table 2. Also, the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion status in Example 9 are shown in Table 2.

[0232] (Examples 10 to 11) A vinyl chloride polymer was synthesized using a polymerization apparatus similar to the polymerization apparatus 100 shown in FIG. 2, except that it did not have the serpentine cooling pipe 140. In Examples 10 to 11, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the presence or absence of the serpentine cooling pipe 140, the rotational speed of the stirring shaft 122, and the charged amount of the raw materials were different. In Examples 10 to 11, the stoichiometric ratio and reaction temperature of each raw material were adjusted in the same manner as in Example 1. Thereby, the influence of the structures arranged inside the reaction vessel can be considered.

[0233] The outline of the specifications of the polymerization apparatuses of Examples 10 to 11 is shown in Table 2. Also, the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion status in Examples 10 to 11 are shown in Table 2.

[0234] (Example 12) A vinyl chloride polymer was synthesized using a polymerization apparatus similar to the polymerization apparatus 100 shown in FIG. 2, except that the number of series of the serpentine cooling pipes in the radial direction of the reaction vessel 110 was tripled. In Examples 10 to 11, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the number of series of the serpentine cooling pipes, the rotational speed of the stirring shaft 122, and the charged amount of the raw materials were different. In Example 12, the stoichiometric ratio and reaction temperature of each raw material were adjusted in the same manner as in Example 1. Thereby, the influence of the structures arranged inside the reaction vessel can be considered.

[0235] The outline of the specifications of the polymerization apparatus of Example 12 is shown in Table 2. Also, the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion status in Example 12 are shown in Table 2.

[0236] (Example 13) A vinyl chloride polymer was synthesized using a polymerization apparatus similar to the polymerization apparatus 100 shown in Fig. 2, except that the number of series of the serpentine cooling pipes in the radial direction of the reaction vessel 110 was five. In Example 13, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the number of series of the serpentine cooling pipes, the rotational speed of the stirring shaft 122, and the charged amount of the raw materials were different. In Example 13, the stoichiometric ratio of each raw material and the reaction temperature were adjusted in the same manner as in Example 1. Thus, the influence of the structures arranged inside the reaction vessel can be considered.

[0237] Table 2 shows an overview of the specifications of the polymerization apparatus of Example 13. Table 2 also shows the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion situation in Example 13.

[0238] (Comparative Example 1) A vinyl chloride polymer was synthesized using a polymerization apparatus similar to the polymerization apparatus 100 used in Example 1, except that the dimensions of the reaction vessel 110 were different. In Comparative Example 1, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the dimensions of the stirring blade 124, and the rotational speed of the stirring shaft 122 were different. In Comparative Example 1, the stoichiometric ratio of each raw material and the reaction temperature were adjusted in the same manner as in Example 1.

[0239] In Comparative Example 1 and Example 1, the L / D of the reaction vessel 110 is different. Therefore, in Comparative Example 1 and Example 1, the flow states inside the reaction vessel 110 are different. As a result, in Comparative Example 1 and Example 1, the stirring conditions under which polymerization can be continued are also different. Therefore, by adjusting the value of b / d and the set value of the rotational speed of the stirring shaft in Formula 1, the stirring conditions in Comparative Example 1 were determined. As a result, the value of b / d in Comparative Example 1 was larger than the value of b / d in Example 1. Also, the value of the stirring parameter in Comparative Example 1 was 6.44.

[0240] Table 3 shows an overview of the specifications of the polymerization apparatus of Comparative Example 1. Table 3 also shows the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion status in Comparative Example 1.

[0241] (Comparative Examples 2 to 5) A vinyl chloride polymer was synthesized using a polymerization apparatus similar to the polymerization apparatus 100 used in Example 1, except that the dimensions of the reaction vessel 110 and the arrangement and pitch width of the serpentine cooling pipe were different. In Comparative Examples 2 to 5, a vinyl chloride polymer was synthesized by the same procedure as in Example 1, except that the dimensions of the reaction vessel 110, the arrangement and pitch width of the serpentine cooling pipe, the dimensions of the stirring blade 124, the rotation speed of the stirring shaft 122, and the charged amount of the raw materials were different. In Comparative Examples 2 to 5, the stoichiometric ratio and reaction temperature of each raw material were adjusted in the same manner as in Example 1. In Comparative Examples 2 to 5, the rotation speed of the stirring shaft 122 was determined such that the value of the stirring parameter exceeded 6.

[0242] Table 3 shows an overview of the specifications of the polymerization apparatus of Comparative Examples 2 to 5. Table 3 also shows the measurement results of the particle size distribution of the vinyl chloride resin, the measurement results of the number of fish eyes, and the confirmation results of the scale adhesion status in Comparative Examples 2 to 5.

[0243] As shown by the results of Examples 1 to 13, by determining the dimensions of the straight body portion of the reaction vessel 110, the dimensions of at least one of the plurality of stirring blades 124, and the set value of the rotation speed of the stirring shaft 122 such that the value of the stirring parameter is 6.0 or less, the generation of coarse particles can be suppressed, and a vinyl chloride resin having a good particle size distribution can be synthesized. It can also be seen that the generation of fish eyes is greatly suppressed. Furthermore, almost no scale generation can be visually confirmed.

[0244] On the other hand, as shown by Comparative Examples 1 to 5, when the value of the stirring parameter exceeds 6.0, coarse particles are generated, and a vinyl chloride resin having a relatively wide particle size distribution is synthesized. Also, a large number of fish eyes are generated, and scale that can be easily confirmed visually is generated.

[0245] Although the cause of the above phenomenon is not clear, for example, the following causes are presumed. That is, the flow state inside the reaction vessel 110 is affected by the L / D of the reaction vessel 110, the structure and arrangement of the internal structures arranged inside the reaction vessel 110, etc. For example, when the L / D of the reaction vessel 110 increases, in order to ensure the fluidity of the fluid inside the reaction vessel 110, it is necessary to increase b. On the other hand, when b increases, in order to maintain the magnitude of the stirring energy added to the raw material at about 80 - 200 kgf·m / s·m 3 it may be necessary to decrease the set value n of the rotation speed. At this time, if the relationship represented by Formula 1 etc. does not hold, the fluidity of the fluid inside the reaction vessel 110 becomes insufficient, and it is considered that problems may occur in the polymerization.

[0246] For the same reason, when the influence of the internal structures arranged inside the reaction vessel 110 on the flow state increases, it becomes difficult to control the stirring state. For example, when the number of series of the serpentine cooling pipes becomes 2 or more, it becomes difficult to control the stirring state. Even in such a case, as shown in Examples 3 to 7, by determining the dimension of the straight body part of the reaction vessel 110, the dimension of at least one of the plurality of stirring blades 124, and the set value of the rotation speed of the stirring shaft 122 so that the value of the stirring parameter becomes 0.3 - 5.5, it can be seen that high-quality vinyl chloride resin can be synthesized even when the number of series of the serpentine cooling pipes is 2 or more. In particular, it can be seen that a great effect is obtained in suppressing the generation of fish eyes.

[0247] [Table 1]

[0248] [Table 2]

[0249] [Table 3]

[0250] As described above, the present invention has been explained using embodiments. However, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0251] It should be noted that in the claims, the specification, and the drawings, the execution order of each process such as the operations, procedures, steps, and stages in the apparatus, system, program, and method shown is not explicitly stated as "before" or "preceding" etc. in particular. Also, unless the output of the previous process is used in the subsequent process, it can be realized in any order. Regarding the operation flow in the claims, the specification, and the drawings, even if it is described using "first," "next," etc. for convenience, it does not mean that it is essential to implement in this order. Examples of embodiments of the present invention are shown below as items. [Item 1] A reactor having a cylindrical straight body portion, A stirring shaft, a part of which is arranged inside the straight body portion and is configured to be rotatable, A plurality of stirring blades attached at different positions in the extending direction of the stirring shaft, Comprising: Each of the plurality of stirring blades is attached at a different position in the extending direction of the stirring shaft, The dimensions of the straight body portion, at least one dimension of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft satisfy the relationship shown in the following mathematical formula 1. (Mathematical formula 1) N(b / d)(L / D) / n ≦ 6.0 (In mathematical formula 1, N represents the number of the plurality of stirring blades, b represents the maximum value [m] of the blade width of the plurality of stirring blades, d represents the maximum value [m] of the blade diameter of the plurality of stirring blades, L represents the length [m] in the extending direction of the straight body portion D is a plane substantially perpendicular to the extending direction of the straight cylindrical portion, and when the straight cylindrical portion is cut by a plurality of planes passing through the attachment positions of the respective stirring blades, it represents the maximum value [m] of the diameters of a plurality of inscribed circles that are substantially inscribed in the straight cylindrical portion in each of the cross-sections formed by the plurality of planes. n represents the set value of the rotational speed [rps] of the stirring shaft. ) Reactor. [Item 2] The dimensions of the straight cylindrical portion, the dimensions of at least one of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft satisfy the relationship shown in the following formula (2). (Formula (2)) 0.05 ≦ N(b / d)(L / D) / n ≦ 6.0 (In Formula (2), the definitions of N, b, d, L, D, and n are the same as those in Formula (1).) The reactor according to Item 1. [Item 3] The straight cylindrical portion further includes a plurality of cooling pipes arranged inside for circulating a refrigerant. At least two of the plurality of cooling pipes have different distances from the inner wall surface of the straight cylindrical portion. The dimensions of the straight cylindrical portion, the dimensions of at least one of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft satisfy the relationship shown in the following formula (3). (Formula (3)) 0.15 ≦ N(b / d)(L / D) / n ≦ 5.5 (In Formula (3), the definitions of N, b, d, L, D, and n are the same as those in Formula (1).) The reactor according to Item 1. [Item 4] The dimensions of the straight cylindrical portion, the dimensions of at least one of the plurality of stirring blades, and the set value of the rotational speed of the stirring shaft satisfy the relationship shown in the following formula (4). (Formula (4)) 0.3 ≦ N(b / d)(L / D) / n ≦ 3.0 (In Formula (4), the definitions of N, b, d, L, D, and n are the same as those in Formula (1).) The reactor according to Item 3. [Item 5] Each of the plurality of cooling pipes has a meandering portion that extends while repeatedly bending. The meandering portion includes a plurality of extending portions that extend linearly or extend curvedly, and a plurality of bending portions that connect the ends of two adjacent extending portions among the plurality of extending portions. The reactor according to item 3. [[Item 6]] [[Item 6]] The ratio of the maximum value of the distance between the two adjacent extending portions to the length of the straight body portion in the extending direction is 0.5 to 15%. The reactor according to item 5. [[Item 7]] The ratio of the minimum value of the distance between the plurality of cooling pipes and the inner wall surface of the straight body portion to the inner diameter of the straight body portion is 0.5 to 10%, and the ratio of the maximum value of the distance between the plurality of cooling pipes and the inner wall surface of the straight body portion to the inner diameter of the straight body portion is 1 to 30%. The reactor according to item 3. [[Item 8]] The stirring shaft is attached to the reactor so that the extending direction of the stirring shaft and the extending direction of the straight body portion substantially coincide, and the minimum value of the distance between the attachment positions of the plurality of stirring blades on the stirring shaft and the position corresponding to one end of the straight body portion on the stirring shaft is 0.1 to 0.45 times the length L of the straight body portion in the extending direction. The reactor according to item 1. [[Item 9]] One end of the straight body portion is the upper end of the straight body portion, and the attachment position of the lowermost stirring blade among the plurality of stirring blades on the stirring shaft is arranged between a first position and a second position of the stirring shaft. The first position is located above the second position when the stirring shaft is attached to the straight body portion, and the distance between the first position and the position corresponding to the lower end of the straight body portion on the stirring shaft is 0.25 times or less the maximum value D of the diameters of the plurality of inscribed circles. The distance between the second position and the position corresponding to the lower end of the straight body portion on the stirring shaft is 0.1 times or less of the maximum value D of the diameters of a plurality of inscribed circles. The reactor according to item 8. [Item 10] Among the plurality of stirring blades, the mounting positions of (N - 2) third stirring blades excluding the first stirring blade mounted at the uppermost position and the second stirring blade mounted at the lowermost position, and the first mounting position which is the mounting position of the first stirring blade and the second mounting position which is the mounting position of the second stirring blade, the maximum value of the distances between the (N - 1) third positions obtained by equally dividing the space between them into (N - 1) parts is 0.5 times or less of the ratio (D / N) of the maximum value D of the diameters of a plurality of inscribed circles to the number N of the plurality of stirring blades. The reactor according to item 1. [Item 11] The internal volume of the reactor is 40 to 300 m 3 and The ratio (L / D) of the length L in the extending direction of the straight body portion to the maximum value D of the diameters of the plurality of inscribed circles is 1.0 to 3.0. The reactor according to item 1. [Item 12] The plurality of stirring blades include paddle blades. The reactor according to item 1. [Item 13] The reactor further includes a control unit that controls the rotational speed of the stirring shaft so that the rotational speed of the stirring shaft satisfies the relationship shown in the formula 1. The reactor according to item 1. [Item 14] A step of polymerizing a vinyl monomer using the reactor according to any one of items 1 to 12 to produce a vinyl polymer. A method for producing a vinyl polymer. [Item 15] A control device for controlling the rotational speed of a stirring shaft that is rotatably arranged inside a reactor and to which a plurality of stirring blades are attached, The reactor has a cylindrical straight body portion, A part of the stirring shaft is arranged inside the straight body portion, The control device controls the rotation speed of the stirring shaft so that the rotation speed of the stirring shaft satisfies the relationship shown in the following mathematical formula 1. (Mathematical formula 1) N(b / d)(L / D) / n≦6.0 (In mathematical formula 1, N represents the number of the plurality of stirring blades, b represents the maximum value [m] of the blade width of the plurality of stirring blades, d represents the maximum value [m] of the blade diameter of the plurality of stirring blades, L represents the length [m] in the extending direction of the straight body portion D represents the maximum value [m] of the diameters of a plurality of inscribed circles that are substantially inscribed in the straight body portion in each of the cross-sections formed by a plurality of planes that are planes substantially perpendicular to the extending direction of the straight body portion and pass through the attachment positions of the plurality of stirring blades when the straight body portion is cut by the plurality of planes. n is the set value of the rotation speed [rps] of the stirring shaft.) Control device. [Item 16] The control device according to Item 15, and the stirring shaft, and a drive unit that rotates the stirring shaft, and comprising The control device controls the rotation speed of the stirring shaft by controlling the output of the drive unit. Stirring device.

Explanation of symbols

[0252] 100 Polymerization apparatus, 110 Reaction vessel, 120 Agitator, 122 Agitation shaft, 124 Agitation blade, 126 Power mechanism, 130 Baffle, 132 Body, 134 Support, 140 Serpentine cooling tube, 150 Serpentine cooling tube, 170 Jacket, 172 Flow path, 180 Reflux condenser, 182 Flow path, 232 Baffle, 234 Baffle, 236 Baffle, 238 Baffle, 242 Serpentine cooling tube, 244 Serpentine cooling tube, 246 Serpentine cooling tube, 248 Serpentine cooling tube, 252 Serpentine cooling tube, 254 Serpentine cooling tube, 256 Serpentine cooling tube, 258 Serpentine cooling tube, 312 Straight body portion, 314 First head plate, 316 Second head plate, 318 Base, 332 Refrigerant supply pipe, 334 Refrigerant return pipe, 342 Connection part, 344 Connection part, 346 Connection part, 510 Inner pipe, 512 Inlet, 520 Outer pipe, 522 Outlet, 532 Pipe, 534 Pipe, 542 Flow rate control valve, 544 Flow rate control valve, 552 Pipe, 554 Flow rate control valve, 556 Pipe, 558 Flow rate control valve, 610 Serpentine part, 612 Extension part, 614 Bend part, 702 Supply pipe, 704 Outlet pipe, 710 Serpentine part, 712 Extension part, 714 Bend part, 810 Serpentine part, 812 Serpentine part, 814 Serpentine part, 816 Serpentine part, 822 Connection part, 824 Connection part, 900 Polymerization device, 1000 Polymerization device, 1100 Polymerization apparatus, 1160, serpentine cooling tube, 1200, polymerization apparatus, 1252, serpentine cooling tube, 1300, polymerization apparatus, 1331, baffle, 1332, baffle, 1333, baffle, 1334, baffle, 1335, baffle, 1336, baffle, 1351, serpentine cooling tube, 1352, serpentine cooling tube, 1353, serpentine cooling tube, 1354, serpentine cooling tube, 1355, serpentine cooling tube, 1356, serpentine cooling tube, 1400, polymerization apparatus, 1403, virtual circle, 1404, virtual circle, 1405, virtual circle, 1500, polymerization apparatus, 1600, polymerization apparatus, 1700, polymerization system, 1702, stirring system, 1710, controller, 1722, stirring blade, 1724, stirring blade, 1726 Stirring blade, 1820 one-dot chain line, 1822 one-dot chain line, 1824 one-dot chain line, 1826 one-dot chain line, 1832 upper end, 1834 lower end, 1842 position, 1844 position, 1852 1st position, 1854 2nd position

Claims

1. A reactor having a cylindrical straight body portion; A stirring shaft, a part of which is disposed inside the straight body portion and configured to be rotatable; A plurality of stirring blades are attached at different positions in the extension direction of the stirring shaft; Equipped with Each of the plurality of stirring blades is attached at a different position in the extension direction of the stirring shaft, The cooling device further includes a plurality of cooling pipes arranged inside the straight body portion for circulating a coolant therethrough, At least two of the plurality of cooling pipes have different distances from an inner wall surface of the straight body portion, The dimension of the straight body portion, the dimension of at least one of the plurality of stirring blades, and the set value of the rotation speed of the stirring shaft satisfy the relationship shown in the following formula 1, (Formula 1) 0.15≦N(b / d)(L / D) / n≦5.5 (In Formula 1, N indicates the number of the plurality of stirring blades, b represents the maximum value [m] of the blade width of the plurality of stirring blades, d represents the maximum value [m] of the blade diameter of the plurality of stirring blades, L indicates the length [m] of the straight body portion in the extension direction. D is a plane that is approximately perpendicular to the extension direction of the straight body portion, and when the straight body portion is cut by a plurality of planes that pass through the mounting positions of each of the plurality of stirring blades, the maximum value of the diameters of a plurality of inscribed circles that are approximately inscribed in the straight body portion in each of the cross sections along the plurality of planes [m], n indicates the set value of the rotation speed [rps] of the stirring shaft. The internal volume of the reactor is 40 to 300 m ３ and a ratio (L / D) of a length L in the extension direction of the straight body portion to a maximum value D of diameters of the multiple inscribed circles is 1.0 to 3.0; Used in the production of vinyl polymers, Reactor.

2. The dimension of the straight body portion, the dimension of at least one of the plurality of stirring blades, and the set value of the rotation speed of the stirring shaft satisfy the relationship shown in the following formula 2. (Formula 2) 0.3≦N(b / d)(L / D) / n≦3.0 (In Formula 2, the definitions of N, b, d, L, D, and n are the same as those in Formula 1.) 2. The reactor of claim 1.

3. Each of the plurality of cooling pipes has a serpentine portion that extends while repeatedly bending, The meandering portion is A plurality of extension portions extending linearly or curvedly; a plurality of bent portions connecting end portions of two adjacent extension portions among the plurality of extension portions; Including, 2. The reactor of claim 1.

4. The ratio of the maximum value of the distance between the two adjacent extension portions to the length of the straight body portion in the extension direction is 0.5 to 15%. The reactor of claim 3.

5. a ratio of a minimum value of a distance between the plurality of cooling pipes and an inner wall surface of the straight body portion to an inner diameter of the straight body portion is 0.5 to 10%; A ratio of a maximum value of a distance between the plurality of cooling pipes and an inner wall surface of the straight body portion to an inner diameter of the straight body portion is 1 to 30%.

2. The reactor of claim 1.

6. The stirring shaft is attached to the reactor so that an extension direction of the stirring shaft and an extension direction of the straight body portion are substantially aligned with each other, The minimum value of the distance between the attachment positions of the plurality of stirring blades on the stirring shaft and the position on the stirring shaft corresponding to one end of the straight body portion is 0.1 to 0.45 times the length L of the straight body portion in the extension direction.

2. The reactor of claim 1.

7. One end of the straight body portion is an upper end of the straight body portion, an attachment position of the lowest one of the plurality of agitation blades on the agitation shaft is disposed between the first position and the second position of the agitation shaft; The first position is located above the second position when the stirring shaft is attached to the straight body portion, A distance between the first position and a position on the stirring shaft corresponding to a lower end of the straight body portion is 0.25 times or less of a maximum value D of diameters of the multiple inscribed circles, The distance between the second position and a position corresponding to the lower end of the straight body portion of the stirring shaft is 0.1 times or less of the maximum value D of the diameters of the multiple inscribed circles.

7. The reactor of claim 6.

8. the maximum value of the distance between the mounting positions of (N-2) third agitating blades, excluding the first agitating blade attached at the top and the second agitating blade attached at the bottom, among the plurality of agitating blades, and the (N-1) third positions obtained by equally dividing the distance between the first mounting position, which is the mounting position of the first agitating blade, and the second mounting position, which is the mounting position of the second agitating blade, into (N-1) positions, is 0.5 times or less of the ratio (D / N) of the maximum diameter D of the plurality of inscribed circles to the number N of the plurality of agitating blades; 2. The reactor of claim 1.

9. The plurality of stirring blades include paddle blades.

2. The reactor of claim 1.

10. A control unit is further provided to control the rotation speed of the stirring shaft so that the rotation speed of the stirring shaft satisfies the relationship shown in the mathematical formula 1.

2. The reactor of claim 1.

11. A method for producing a vinyl polymer by polymerizing a vinyl monomer using the reactor according to any one of claims 1 to 10. A method for producing a vinyl polymer.

12. A control device for controlling the rotation speed of an agitation shaft rotatably disposed inside a reactor and having a plurality of agitation blades attached thereto, comprising: The reactor has a cylindrical body portion, a plurality of cooling pipes arranged inside the straight body portion for circulating a coolant; A part of the stirring shaft is disposed inside the straight body portion, At least two of the plurality of cooling pipes have different distances from an inner wall surface of the straight body portion, The control device controls the rotation speed of the stirring shaft so that the rotation speed of the stirring shaft satisfies the relationship shown in the following mathematical formula 1, (Formula 1) 0.15≦N(b / d)(L / D) / n≦5.5 (In Formula 1, N indicates the number of the plurality of stirring blades, b represents the maximum value [m] of the blade width of the plurality of stirring blades, d represents the maximum value [m] of the blade diameter of the plurality of stirring blades, L indicates the length [m] of the straight body portion in the extension direction. D is a plane that is approximately perpendicular to the extension direction of the straight body portion, and when the straight body portion is cut by a plurality of planes that pass through the mounting positions of each of the plurality of stirring blades, the maximum value of the diameters of a plurality of inscribed circles that are approximately inscribed in the straight body portion in each of the cross sections along the plurality of planes [m], n is the set value of the rotation speed [rps] of the stirring shaft. The internal volume of the reactor is 40 to 300 m ３ and a ratio (L / D) of a length L in the extension direction of the straight body portion to a maximum value D of diameters of the multiple inscribed circles is 1.0 to 3.0; Used in the production of vinyl polymers, Control device.

13. A control device according to claim 12; The stirring shaft; A drive unit that rotates the stirring shaft; Equipped with The control device controls the rotation speed of the stirring shaft by controlling the output of the drive unit. Stirring device.

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