JP3554622B2 - Horizontal single-shaft reactor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a horizontal single-screw reactor suitable for performing a process involving mass transfer of a viscous liquid. More specifically, the present invention relates to a horizontal single-screw reactor having excellent performance in a wide viscosity region, particularly in a high viscosity region. It relates to a shaft reactor.
[0002]
[Prior art]
In processes involving mass transfer of viscous liquids, such as continuous polymerization of polymers using transesterification of polyesters and polycarbonates, removal of volatiles in polymers, and absorption of gaseous components into polymers, low-boiling components can be used in liquids. It is known that the diffusion in the reactor is closely related to the efficiency, and a horizontal reactor is often used to reduce the liquid depth of the substance to be treated.
[0003]
There are two types of horizontal reactors, one-shaft and two-shaft. The horizontal single-shaft reactor is inexpensive, but the applicable viscosity range is narrower than the two-shaft type, and the horizontal twin-shaft reactor has a wide usable viscosity range. It has the disadvantage of being expensive but expensive. Therefore, there is a demand for an expansion of the usable viscosity range in a horizontal single-shaft reactor that can be manufactured at low cost.
[0004]
For this reason, many shapes of stirring blades used for a horizontal single-shaft reactor have been studied, and in this process, an end disk and a plurality of partition disks arranged between the end disks are separated. There has been proposed a horizontal single-screw reactor having a structure in which a stirring blade that is inclined or curved in a direction opposite to the rotation direction is connected and fixed at a predetermined interval and a center portion of a disk at both ends is supported by a rotation shaft.
[0005]
In this type of horizontal single-shaft reactor, there is no stirring shaft in the center of the rotating structure, so that co-rotation of the liquid around the shaft due to the increase in liquid viscosity is prevented, while the stirring blades pump the liquid and rotate it. It is an excellent reactor that can drop while forming a free surface together with it, and achieve a large specific surface area by forming a liquid film on the inner wall of the reactor, but due to its structure, the liquid viscosity is high When it falls, the ability to form a free surface is reduced, and the specific surface area is reduced, resulting in a decrease in efficiency.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to connect and fix an end disk and a plurality of partition disks disposed between the end disks at predetermined intervals by stirring blades inclined or curved in a direction opposite to the rotation direction, Further, a horizontal single-screw reactor having the advantage of a horizontal single-screw reactor having a structure in which the center portions of both end disks are supported by a rotating shaft and further expanding the applied viscosity to a particularly high viscosity side is provided. It is in.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve these problems, and as a result, have found that the stirring blades can be solved by specially devising them, and have reached the present invention.
[0008]
That is, the present invention provides, in a substantially cylindrical reactor, an end disk rotating in a certain direction and a plurality of partition disks having an opening at the center between the end disks. The horizontal die 1 has a structure in which these disks are connected and fixed at predetermined intervals by stirring blades inclined or curved in the direction opposite to the rotation direction thereof, and the center portions of both end disks are supported by a rotating shaft. What is claimed is: 1. A horizontal single-shaft reactor, wherein a plurality of openings are provided in the stirring blade, and the opening degree of the stirring blade is sequentially increased from the inlet side to the outlet side of the reaction liquid. Further, there is provided a horizontal single-shaft reactor characterized in that a tail end extending in the direction opposite to the rotation direction and having a small gap with the inner wall of the reactor is provided at the tip of the stirring blade.
[0009]
In the horizontal single-shaft reactor of the present invention, a plurality of partition discs arranged almost in parallel between two end discs inside the reactor are rotated in a direction opposite to the rotation direction of these discs. Even if the hold-up is raised, the reaction liquid (processing liquid) is pumped up by the stirring and rotation by the space formed by the tip of the blade and the inner wall of the reactor even if the hold-up is increased, and then free by gravity. Since the liquid falls while forming a liquid film, and the liquid is applied to the gas phase portion of the inner wall of the container by the stirring blade, the surface area of the reaction liquid is kept large in the reactor, and as a result, high mass transfer is achieved. Speed and productivity are maintained.
[0010]
Then, two end disks having a stirring shaft (rotating shaft) provided at both ends inside the reactor are connected and fixed by a plurality of stirring blades via a partition disk having an opening at the center. Therefore, there is no stirring shaft inside the stirring blade, and there is no stagnation portion around the shaft, which is particularly problematic when the liquid viscosity increases.
[0011]
In the reactor of the present invention, the stirring blade for connecting and fixing the partition disk and the end disk is constituted by a perforated plate having a plurality of openings, and the like. The degree of opening is sequentially increased. By doing so, a high mass transfer rate can be obtained even when the viscosity of the processing liquid is high, and the applied viscosity can be increased. The shape of the plurality of openings is preferably a plate-shaped stirring blade provided with a plurality of circular or square openings, but may be one in which slits are formed at predetermined intervals.
[0012]
In the present invention, a flat plate (perforated plate) having a circular opening can be used as a component of the stirring blade having a plurality of openings. The circular opening diameter is preferably 1 to 100 mm. If the opening diameter is smaller than this, the movement of the high-viscosity processing liquid through the opening is hindered, which is not preferable. Further, when the opening diameter is further increased, the strength of the blade that withstands the torsional force generated by the stirring rotation decreases. The ratio of the openings to the area of the stirring blade (opening degree) is preferably 30% or more in total. There is no particular limitation on a method for forming such an opening, and for example, punching, cutting, or the like can be used, or a punching plate can be used.
[0013]
The opening degree is increased continuously or stepwise from the reaction liquid inlet side to the outlet side within the above-mentioned range. Preferably, the opening degree of the liquid inlet side of the reactor is 1 to 80%, The opening degree on the liquid discharge side is selected from the range of 2 to 90%.
[0014]
In the present invention, when a flat plate having a circular opening is used as a material for the stirring blade, different effects are obtained depending on the opening diameter of the flat plate having the circular opening and the viscosity of the reaction solution. For example, when the viscosity of the reaction liquid is higher than 3000 poise, by forming the stirring blade with a flat plate having a circular opening having a diameter larger than 5 mm, the stirring liquid passes through the opening due to a relative speed difference between the reaction liquid and the stirring blade caused by the stirring rotation. The reaction liquid flows on the back side of the stirring blade, preventing the liquid from remaining on the surface of the stirring blade and forming a liquid pool on the back side of the blade, which increases the surface area by falling while forming a free liquid film due to gravity. And the reaction speed increases. This effect is effective for increasing the applied viscosity. When the viscosity of the reaction solution is lower than 100 poise, the specific surface area of the reaction solution is increased by forming the stirring blade with a material having an opening smaller than 5 mm, and the reaction speed is increased. This effect is more remarkable as the viscosity of the reaction solution is lower, and is effective in increasing the applied viscosity.
[0015]
In addition, a wire mesh can be used as a material of the stirring blade in the present invention. In this case, it is necessary to withstand the torsional force generated by the stirring rotation, and it is preferable to use together with the frame-shaped reinforcing member.
[0016]
In the present invention, the mesh of the wire mesh used preferably has an opening larger than 1000 mesh. If the size of the opening is smaller than this, the flow of the processing liquid attached to the wire netting is hindered, and it becomes difficult to renew the surface, which causes a reduction in efficiency and a deterioration of the processing liquid due to long-term retention, which is not preferable.
[0017]
In the present invention, as the shape of the stirring blade having an opening, a columnar or prismatic material may be arranged at a predetermined interval, and the gap (slit) may be used as the opening. In this case, the interval between the columnar and prismatic materials constituting the stirring blade is preferably 1 mm or more. If the distance is too small, the processing liquid co-rotates with the stirring blades, which hinders the movement of the high-viscosity processing liquid through the opening, which is not preferable.
[0018]
In any case, the adaptive viscosity is increased by sequentially increasing the opening degree of the stirring blade from the processing liquid inlet side to the processing liquid inlet side of the reactor in accordance with the increase in viscosity.
[0019]
That is, in the present invention, in the region where the viscosity of the treatment liquid is low, for example, a stirring blade is formed using a fine mesh wire mesh, and as the viscosity of the liquid increases, a punching plate having a large opening diameter or a circular shape having a large opening diameter is used. By forming the stirring blade using a flat plate having the above opening, the applicable viscosity range of the horizontal single-screw reactor can be greatly expanded.
[0020]
In the present invention, it is preferable that a stirring blade having a plurality of openings as described above is provided with a tail at its tip which extends in a direction opposite to the rotation direction of the stirring blade and holds a small gap with the inner wall of the container. The installation of the tail fin has the effect of applying the liquid film to the inner wall of the container and improving the pumping ability of the reaction solution. It is preferable that the surface area of the tail is provided with a difference between the liquid inlet side and the outlet side of the reactor, so that the surface area of the outlet side is made smaller. In addition, the installation angle θ of the tail fin is in a range of 0 ° (arc along the circumference) to 60 °.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an example of the horizontal single-shaft reactor of the present invention will be described with reference to the drawings.
FIG. 1 is a sectional view showing a horizontal single-screw reactor according to the present invention, and FIGS. 2 and 3 are views taken along arrows AA and BB in FIG. 1, respectively.
[0022]
In the figure, 1 is a hollow cylindrical reactor main body, 2 is a heating device surrounding the main body, 3 and 4 are inlet and outlet of a reaction liquid (treatment liquid), respectively, and 5 and 6 are side plates (or end plates) on both sides. It is. Reference numeral 7 denotes a plurality of blades having inner ends fixed to a rotating shaft 8 at a position close to the side plate 5 on the inlet 3 side, and curved in a direction opposite to the rotating direction R (hereinafter, viewed from the center or the axis). And the blade surface F in the direction of the rotation axis is inclined so as to scrape and apply the reaction liquid to the side wall 5. A similar blade 7 'is provided at the other end.
[0023]
Reference numerals 9, 9 'denote end disks provided on the rotating shafts 8, 8' and provided inside the blades 7, 7 '. Or the liquid distribution to the outlet 4 can be appropriately performed.
[0024]
Reference numeral 11 denotes a plurality of (six in FIG. 1) partition disks which are arranged and supported substantially in parallel at predetermined intervals through a plurality of stirring blades 13 between the end disks 9, 9 '. An opening at the center of the partition disk 11.
[0025]
The stirring blades 13 are fixed to the outer peripheral portion of the partition disk 11 at regular intervals, extend in a direction substantially perpendicular to the disk surface, and are composed of a plurality of plate-like bodies that connect the partition disks 11 to each other. However, as shown in FIGS. 2 and 3, the tip is inclined in the direction opposite to the rotation direction R and the tip is close to the body wall 1 inside the reactor body, and is formed by the stirring blade 13 and the body wall 1. In the space S, the reaction solution is scraped up and applied to the body wall 1.
[0026]
The stirring blade 13 is formed of a perforated plate or the like having a plurality of openings, and the opening ratio of the stirring blade 13 is relatively small at the inlet side of the reactor and gradually increases toward the outlet side. ing.
[0027]
Further, a tail 14 extending in the direction opposite to the rotation direction R is provided at the tips of the stirring blades 13 in the vicinity of the body wall 1 in order to effectively perform the application distribution action. The tail blade 14 is provided so as not to protrude as much as possible from the surface of the stirring blade 13 on the rotation direction R side.
[0028]
Further, the tail fins 14 may be provided in all the chambers formed by the partition disks 11 along the axial direction as in this example, or may be provided in a part according to the viscosity of the processing liquid. The surface area of the tail 14 in each chamber may be changed according to the increase or decrease in the viscosity of the processing solution in the inside.
[0029]
In addition, the gap between each of the partition disk 11, the stirring blade 13, and the tail blade 14 and the body wall 1 is preferably 10 mm or less, and more preferably 5 to 8 mm, and the gap between the entrance-side blade 7 and the side plate 5 is also preferable. Is preferably 3 mm or less, and the gap between the blade 7 'on the outlet side and the side plate 5' is preferably 10 mm or less. Furthermore, the blades 7, 7 'may be combined with the end disks 9, 9' to form an integrated body.
[0030]
【The invention's effect】
According to the present invention, a horizontal single-shaft reactor having excellent performance in a wide viscosity range is provided. In particular, this reactor is particularly useful as a reactor in melt polymerization of polycarbonate, in which the viscosity of the reaction solution increases.
[0031]
【Example】
Hereinafter, a use example of the horizontal single-screw reactor of the present invention will be described in detail by taking melt polymerization of polycarbonate as an example. The percentages and parts in the examples are% by weight or parts by weight unless otherwise specified. The present invention is not limited by the embodiment.
[0032]
[Example 1]
Diphenyl carbonate was charged into a melting tank equipped with a stirrer at a ratio of 1.01 mol per mol of 2,2-bis (4-hydroxyphenyl) propane, and after displacing with nitrogen, dissolved at 150 ° C. It was transferred to a raw material storage tank maintained at 150 ° C.
[0033]
Next, the molten mixture was continuously supplied at a rate of 60 Kg / Hr to a vertical stirring tank equipped with a rectification tower and maintaining the internal temperature at 240 ° C. and the internal pressure at 10 Torr, and at the same time, 2,2-bis (4 Dispersion of bisphenol A disodium salt (equivalent to 0.000012 parts by weight) per mole of (hydroxyphenyl) propane (0.00002 equivalents) was continuously supplied as a polymerization catalyst, and the reaction was carried out while removing the produced phenol from the rectification column. Was. The obtained reaction product was continuously extracted using a gear pump. The degree of polymerization of the obtained reaction product was determined by measuring the intrinsic viscosity. The intrinsic viscosity was determined by measuring a 0.7 g / dl methylene chloride solution of a reaction product using an Ubbelohde viscosity system. As a result, it was found that a prepolymer having [η] = 0.16 was obtained.
[0034]
Next, the prepolymer was continuously supplied to a horizontal single-screw reactor as shown in FIGS. 1 to 3 rotating at 5 rpm while maintaining the internal temperature at 270 ° C. and the internal pressure at 1 Torr. The horizontal single-shaft reactor has eight sections separated by an end disk and a partition disk, and the first four sections on the reaction solution supply side are stirring blades constituted by a 300 mesh wire mesh. The 4 sections on the downstream side (reaction liquid extraction side) are punched plates made by punching a SUS316 metal plate with a diameter of 8 mm so that the total opening area becomes 35% (larger than the wire netting). It is provided with the constituted stirring blade. The gap between the stirring blade and the inner wall of the reactor was designed to be 7 mm.
[0035]
Using this reactor, a polycarbonate having [η] = 0.45 was continuously produced by further polymerizing while removing generated phenol out of the system.
[0036]
The viscosity of the reaction solution at the inlet side of the horizontal single-shaft reactor was equivalent to 30 poise at 270 ° C., and the viscosity of the withdrawn reaction solution was equivalent to 14000 poise at 270 ° C. The average polymerization rate during this time was 0.3 (1 / Hr), expressed as △ [η] / △ t.
[0037]
[Comparative Example 1]
The operation was performed in the same manner as in Example 1 except that all the stirring blades of the horizontal single-shaft reactor were formed of a SUS316 metal plate having no opening. As a result, the average polymerization rate of the horizontal single-screw reactor was 0.21 (1 / Hr).
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of the structure of a horizontal single-screw reactor according to the present invention. FIG. 2 is a view taken along a line AA in FIG. 1. FIG. 3 is a view taken along a line BB in FIG. Description]
DESCRIPTION OF SYMBOLS 1 Reactor main body 2 Heating device 3 Processing liquid inlet 4 Processing liquid outlet 5, 6 Side plate (or end plate) on both sides
7, 7 'Blades 8, 8' attached to rotating shafts on both sides Rotating shafts 9, 9 'End disks 10, 10' with notches on the outer periphery Notch opening 11 Partition disk 12 Center of partition disk Opening 13 Stirring blade 14 Tail provided on stirring blade

Claims (2)

In a cylindrical reactor, an end disk rotating in a certain direction and a plurality of partition disks having an opening in the center are provided in parallel between the end disks, and these disks are rotated in the rotation direction. A horizontal single-screw reactor having a structure in which it is connected and fixed at predetermined intervals by stirring blades that are inclined or curved in the opposite direction to each other, and has a structure in which the center portions of both end disks are supported by a rotating shaft, wherein a plurality of stirring blades are provided. A horizontal single-screw reactor characterized in that the opening of the stirring blade is sequentially increased from the inlet side to the outlet side of the reaction solution. The stirring blade disposed between the end disk and / or the partition disk has a tail at its tip extending in a direction opposite to the rotation direction and holding a small gap with the inner wall of the reactor. The horizontal single-shaft reactor according to claim 1.

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