JPS6365082B2 - - Google Patents

Description

[Detailed description of the invention]

[] Background of the Invention The present invention relates to a novel horizontal reactor for gas phase polymerization of olefins for homopolymerization and copolymerization of olefins to produce polymers in a state in which olefins are substantially present in the gas phase. . Currently, the mainstream method for polymerizing α-olefins is the so-called slurry polymerization method in which polymerization is carried out in the presence of a diluent. Such slurry polymerization requires diluent recovery and purification steps;
In the so-called gas phase polymerization method in which olefins are reacted in a gas phase, such a step is substantially unnecessary, and the process can be simplified and the amount of utilities such as steam and electricity can be reduced. In this gas phase polymerization method, a fine polymerization catalyst is dispersed in a reaction tank either as it is, dispersed in a small amount of dispersion medium, or supported on a fine powder carrier such as silica or alumina. A polymer is grown on the catalyst by contacting it with a gaseous olefin. The polymer powder that has been placed in advance in the reaction tank or the polymer powder that has already been produced by polymerization is kept in a stirred state, and the contact between the gas phase olefin and the catalyst is made while the polymer powder is in the stirred state. Therefore, it is greatly affected. Generally, the heat generated during polymerization of olefins is extremely large, about 10 to 20 Kcal/mol, and if stirring conditions are not good, local overheating may occur.
This will cause problems in carrying out the polymerization reaction and deterioration in the quality of the produced polymer. In addition, it is necessary to efficiently remove the heat of polymerization that is generated in large quantities, and if the heat removal is not sufficient, problems will occur in controlling the temperature of the polymerization reaction, as well as troubles in carrying out the reaction and problems in the production of polymers. This causes quality deterioration. Therefore, in the gas phase polymerization of olefins, uniform heat removal from such a fluidized bed is a major problem as well as the contact state between the gas phase and the solid phase, that is, the fluidized and agitated state of the powder. As a reaction apparatus for gas phase polymerization of olefins, a fluidized bed reactor is proposed, for example, in Japanese Patent Publications No. 47-13962, Japanese Patent Publication No. 52-040350, and Japanese Patent Publication No. 54-139983. Although these fluidized bed reactors are superior in that they mix polymer particles and catalyst particles in a gas phase substantially free of diluent,
On the other hand, it has the following drawbacks. (1) In order to create an effective fluidized state of polymer particles and catalyst particles in a fluidized bed reactor, it is necessary to blow a large amount of gas from the bottom of the reactor, and even if polymerization raw material gas is used as this gas, The amount of gas is several tens of times greater than the reaction amount, and this gas is taken out of the reactor and recycled. This recirculation requires a compressor of considerable capacity, which consumes a large amount of power. (2) The rising rate of the gas for mixing inside the fluidized bed reactor is:
For example, as shown in Japanese Patent Publication No. 52-40350, the rate is about 15 cm/sec, and the catalyst particles and active fine powder in the middle of the reaction are scattered into the mixing gas circulation system on this rising air current. Not only does this require special fines collection equipment, but in some cases the catalyst and active fines also get deposited on the pipes and equipment of the mixing gas circulation system, where polymerization reactions take place and eventually the mixing This makes operation of the gas circulation system difficult. In order to avoid this, special consideration must be given to the catalyst system so as not to generate fine powder, and the catalyst systems that can be used are also limited. On the other hand, attention has been paid to the above-mentioned drawbacks of the fluidized bed reactor, and a method of reducing the flow rate of gas blown into the fluidized bed reactor has been proposed. For example, the Special Public Interest Publication 41-597
The publication proposes a method in which a stirrer is installed in a fluidized bed reactor. However, even with this method, it is described that it is still necessary to supply gas at a rate of 5 to 15 cm/sec from the bottom of the reactor. Also, special public service in 1977-
Publication No. 2019 proposes a method of carrying out gas phase polymerization using an apparatus in which a uniaxial stirrer is installed inside a horizontal hollow cylindrical reactor. In gas phase polymerization using this apparatus, a method is used in which the heat of polymerization is removed by latent heat of vaporization by injecting a low boiling point liquid such as isobutane or isopentane into the apparatus, thereby reducing the amount of flow gas blown into the apparatus. However, even this method has the following drawbacks. (1) Since reaction products accumulate on the inner surface of the reactor, it is necessary to blow purge gas to remove the accumulated substances. (2) A large amount of equipment is required to recover and circulate the low-boiling point liquid, and a large amount of electricity, steam, etc. is also consumed. As described above, the devices and methods proposed so far cannot be said to be fully satisfactory in terms of stable operation of the reactor and reaction system and reduction in utility consumption. JP-A No. 55-157605 discloses a horizontal reactor that achieves uniform mixing of the reaction system using a plurality of parallel stirring shafts installed horizontally at the bottom of the reaction tank, thereby making it possible to equalize the reaction heat. Proposed. Therefore, this reactor is excellent in terms of stable operation of the reactor, but by efficiently removing polymerization heat and reducing the load on the gas circulation system, the equipment cost and utility in the circulation system are reduced. It is still insufficient in terms of reducing the amount used. The present inventors have further investigated the horizontal reactor proposed in JP-A No. 55-157606, and have developed an internal cooling system without impairing the stability of the polymerization reaction of this reactor. It has been found that the above-mentioned drawbacks can be almost completely overcome by efficiently removing the heat of polymerization. [] Summary of the Invention The present invention provides a horizontal reactor for gas phase polymerization in which homopolymerization and copolymerization of α-olefins is carried out in a substantially gaseous state of at least one α-olefin. A pair of stirring shafts are provided horizontally and in parallel, and each stirring shaft is equipped with a stirring blade that can stir up the powdered olefin polymer in the reaction tank by rotation. The bottom of the reaction tank consists of a partial cylinder that follows the trajectory created by the rotation of the tips of the stirring blades on each stirring shaft, and a cooling pipe for removing polymerization heat is installed in the fluidized bed created by stirring. In an apparatus for gas-phase polymerization of olefin, a large number of cooling pipes for removing polymerization heat are installed horizontally, and the intervals between the cooling pipes are coarse in the ascending part of the flow of the powdered olefin polymer. This is an apparatus for vapor phase polymerization of olefin, which is characterized in that the descending section is densely arranged. 3.5-5.0 in portion
and is preferably 1.5 to 3.5 in the dense part, and is particularly effective when the rotation of the paired stirring shafts is in the direction of stirring up the powdered olefin polymer between the two rotating shafts. . When the homopolymerization and copolymerization of α-olefins is carried out using the apparatus of the present invention in a state in which at least one α-olefin is substantially in the gas phase, the following advantages are obtained. First of all, the installation of internal cooling means does not substantially change the flow conditions within the reactor and does not impair the polymerization stability of the reactor. In other words, due to the interaction of the stirring blades arranged on the paired rotating shafts,
It is possible to provide the contents with the same degree of fluidity as in a conventional fluidized bed reactor, using only mechanical stirring,
Moreover, the temperature distribution inside the reactor is approximately ±2°C, and there is no formation of lumps, etc., which are thought to be caused by temperature non-uniformity, and the reactor can be operated smoothly for a long time. In particular, since the cooling pipes are installed horizontally, they have good contact with the powder polymer flowing up and down, resulting in good cooling efficiency.In addition, the cooling pipes are arranged sparsely in the rising part of the powder polymer flow. Therefore, the upward motion of the powdered polymer by the stirring blades is less obstructed, and the cooling effect is not impaired because the cooling pipes are densely arranged in the part where the powdered polymer descends due to gravity. Therefore, due to the internal cooling means within the reactor, approximately
Since 100% of the heat of polymerization is removed, the amount of gas blown can be essentially the same as the amount of polymer produced, eliminating the need for a circulation system for excess gas or eliminating the need for a circulation system. Even if it is installed, it can be done on a small scale, and the capital investment and utility usage in the circulation system can be greatly reduced. Furthermore, there is virtually no problem of adhesion to pipes and equipment due to the contamination of finely divided polymers and active finely divided polymers into the circulation system. [] Detailed Description of the Invention In the polymerization apparatus of the present invention, two stirring shafts are arranged in the lower part of the reaction tank. These stirring shafts are provided horizontally and in parallel. The spacing between the two stirring shafts arranged in parallel is preferably such that the two rotation circles drawn by the stirring blades attached to the shafts touch or overlap. The two rotation circles may be separated, but as the separation increases, the interaction between both stirring blades decreases. Although there are no particular limitations on the shape of the stirring blades, those having paddle blades are generally used in order to stir up the powder in the reaction tank upwards. For an upward scraping effect, it is best to place the paddle blades parallel to the stirring shaft, but to create a gentle circulation flow throughout the reaction tank, the paddle blades may be tilted or horizontally placed. Types such as a combination of inclined blades or a part of helical ribbon blades are adopted. A plurality of stirring blades are mounted symmetrically on the stirring shaft. Three blades or four blades can also be used, but usually
Two blades with a spacing of 180° are sufficient. The spacing between the stirring blades in the axial direction is arbitrary, but from the standpoint of stirring effectiveness, it is preferable that they be close to each other, and they are usually installed at intervals of 1.5 to 3 times the width of the blades. The relative positions of the stirring blades between the two shafts are such that both blades do not come into contact with each other due to rotation. The rotational direction of the stirring shaft, that is, the rotational direction of the stirring blades may be arbitrary. In other words, when looking at two stirring shafts from the axial direction, if the right shaft rotates clockwise (clockwise) and the left shaft rotates counterclockwise (outward rotation), then the right shaft rotates counterclockwise and the left shaft rotates counterclockwise. There are cases where the axis rotates clockwise (inward rotation) and cases where both axes rotate in the same direction (same direction rotation). From the viewpoint of uniformity of stirring, outer rotation or inner rotation is preferable. However, in the case of inner rotation, the scraping effect of the powder is lower than in the case of outer rotation, so the heat removal effect by the cooling pipe is slightly reduced, and if the rotation is in the same direction, powder particles may stagnate. Because parts tend to occur,
It is most preferable to use external rotation. The rotational speed of the stirring blade is determined by the size of the reaction tank, the size and number of blades, etc. In order to obtain a sufficient stirring effect, the rotation speed is generally set so that the height of the powder in the reaction tank is approximately 0.5 to 2.5 of the rotational diameter of the stirring blade at a height above the top of the blade. be done. Although such a rotational speed varies depending on the shape of the blade, etc., it will generally be a rotational speed that provides a linear speed of about 1 to 7 m/sec. The bottom of the polymerization reaction tank is composed of a partial cylinder along the trajectory drawn by the stirring blades of each stirring shaft, but the limit of this partial cylinder is up to 1/2 the circumference. That is, when the rotation circles of both axes are separated from each other, a chevron-shaped connection part is provided at the bottom of the reaction tank in the middle part to prevent powder from stagnation. It is preferable that the clearance between the bottom of the reaction tank and the tip of the stirring blade be as small as possible to prevent the accumulation of powder.
Generally, 10mm or less is desirable. The height of the polymerization reaction tank is desirably greater than the height of the agitated and floated powder, and therefore is at least 1.2 times, preferably 1.5 to 5 times, the diameter (D) of the maximum rotation circle defined by the stirring blade. More preferably, it is 1.5 to 4.0 times. The length of the tank in the axial direction is arbitrary, but it is usually 1 to 6 times, preferably 2 to 3 times the diameter (D) of the rotating circle. The amount of powder in the polymerization reaction tank can be any amount as long as a sufficient stirring effect can be obtained, but normally the amount should be below the position near the highest point of the stirring blade when the stirring blade is stopped. Preferable for stirring effect. The cooling pipe for removing polymerization heat must be able to efficiently remove polymerization heat and not impair polymerization stability. That is, it is necessary to increase the heat transfer area and the heat transfer coefficient without disturbing the fluid state caused by stirring up the powdered polymer by the stirring blade. For this purpose, the cooling tubes in the device of the invention are placed in the fluidized bed below the upper surface of the fluidized bed of powdered polymer produced by stirring. Further, the cooling pipe is a thin pipe, installed horizontally (hereinafter referred to as a horizontal pipe), and is usually used parallel to the stirring shaft. A cooling pipe is installed substantially vertically and perpendicularly to the stirring shaft (hereinafter referred to as a vertical pipe), and through the gap between the stirring blades arranged on the stirring shaft (hereinafter referred to as a blade gap insertion pipe). However, in general, a vertical pipe has a lower heat transfer coefficient than a horizontal pipe, and a blade gap insertion pipe itself has a small heat transfer area. In the apparatus of the present invention, the horizontal pipes are arranged sparsely in the upward flow section and densely arranged in the downward flow section within the fluidized bed. That is, if the fluidized bed is divided into three sections by erecting virtual vertical planes for the two stirring shafts, it is possible to determine whether the flow of the powdered polymer is in the upward direction or in the downward direction in each space. be done. For example, when the rotation of the two stirring shafts is the most preferable outward rotation for a fluidized bed, the flow of the powdered polymer is in the upward direction in the space section sandwiched between the two rotating shafts, and In one space, the flow of powdered polymer is downward. Although the horizontal tubes can be arranged in any desired arrangement, generally a square arrangement or a triangular arrangement is adopted. The density of the arrangement can be expressed by the pitch, which is the distance between the centers of adjacent horizontal tubes divided by the diameter of the horizontal tubes. As mentioned above, when the stirring shaft rotates outward, the pitch of the horizontal tube is preferably 3.5 to 5.0 in the ascending fluidized bed sandwiched between the two stirring shaft surfaces, and the descending fluid flow between each shaft surface and the side wall. In space, Pituchi is 1.5~
3.5, preferably 1.5 to 3.0, horizontal pipes are installed. It goes without saying that in order to increase the heat transfer area of the cooling tubes, it is sufficient to reduce the pitch of the horizontal tubes, but for example, if the pitch is set to 2.4 and the horizontal tubes are installed throughout the fluidized bed, the The flow state changes greatly compared to when no cooling pipe is installed, and when the stirring shaft is rotated outwardly, the flow surface becomes raised on the side wall as shown in FIG. 4. In such a fluid state, the entire horizontal pipe does not effectively contribute to heat transfer, which not only reduces the heat transfer area, but also tends to cause stagnation and uneven pressure of powder particles.
Particularly, lumps are likely to form in the space sandwiched between both stirring shafts as shown by diagonal lines in FIG. In addition, if the pitch is 3.5 or more and the horizontal pipes are uniformly arranged throughout the reactor, the flow state will be uniform within the reaction tank as shown in Figure 5, the above problem will disappear, and the polymerization stability will be reduced. However, on the other hand, there is a possibility that the heat transfer area is insufficient and the production capacity will not be fully utilized in terms of removing polymerization heat. In the apparatus of the present invention, this problem is solved by arranging the horizontal tubes sparsely in the ascending part of the powder in the fluidized bed and densely in the descending part. In the rising part of the fluidized bed where the powder is thrown up by the stirring blades, the pitch of the horizontal pipe arrangement is set to 3.5 or more to prevent the influence of the horizontal pipes on the flow state. However, Pituchi
If it exceeds 5.0, the heat transfer area becomes small, which is not preferable. In addition, in the part where the sputtered powder descends due to gravity, the pitch of the horizontal pipe is set to 3.5 or less, preferably 3.0 or less to increase the heat transfer area.
Sufficient cooling is ensured. However, if the pitch is less than 1.5, the movement of the powder descending between the horizontal pipes will be suppressed, and stagnation will likely occur, which is undesirable, as it will tend to generate lumps. In the apparatus of the present invention, by installing such a cooling pipe in the fluidized bed created by the violent stirring or splashing effect by the stirring blades, the powder violently collides with the entire cooling pipe. The heat transfer surface of the cooling tube can be updated, the heat transfer coefficient can be increased by disturbing the boundary surface, and it has become possible to effectively remove polymerization heat. In conventional vertical stirring tanks, relatively large stirring blades are installed to give movement to the contents of the reactor, so it is difficult to install an internal cooler, and even if installed, the movement of the contents is Since the reaction is not as severe as in the reaction tank of the present invention, stagnation occurs near the cooling pipe, which tends to cause problems such as the formation of lumps. Hereinafter, the present invention will be specifically explained with reference to embodiments shown in the drawings. FIG. 1 shows the vicinity of the end face of a cross section perpendicular to the rotational axis of the apparatus of the present invention, and piping other than the cooling pipe is omitted. FIG. 2 is a sectional view taken along line A--A in FIG. 1 and parallel to the rotation axis. Two rotating shafts 2 and 3 are parallel to each other at the bottom of the reaction tank, and bearings 9 and 10 are attached to the outer shell 1 of the reaction tank at both ends.
A stirring blade consisting of a support body 4 and a paddle blade 5 is attached on each rotating shaft. For example, as shown in FIG. 2, the stirring blade has two supports 4 attached symmetrically to the stirring shaft and paddle blades 5 attached to their tips, forming one stirring blade unit 6. Several units are attached to each stirring shaft at equal intervals. In this embodiment, the mounting positions of the stirring blades on both stirring shafts 2 and 3 are the same, and the rotating orbits of the stirring blades on both shafts overlap as shown in FIG. Therefore, in order to prevent the stirring blades on both shafts from coming into contact with each other, the attachments of the respective supports 4 are offset from each other by 90°.
Both stirring shafts are rotated at the same speed by a drive device 11. The stirring shaft 2 and the stirring shaft 3 have opposite rotation directions, and are of an outer rotation type as shown by the arrows in FIG. In the stirring blade unit 6 shown in FIG. 3, the paddle blades 5 consist of horizontal paddles parallel to the stirring shaft 2, and the rotation of the stirring shaft 2 violently stirs the powder in the polymerization reaction tank up and down. The bottom of the reaction tank has a partially cylindrical shape along the outermost rotational orbit of the stirring blade, and a polymer discharge port 12 is provided in a part of the bottom. In FIG. 1, several horizontal cooling pipes 7 are installed in a triangular arrangement parallel to the stirring axis in the space above the stirring blade in the reaction tank 1. The arrangement is a virtual vertical plane erected to stirring shaft 2 and stirring shaft 3, respectively.
The pitch is 4.0 in the flow space between V ₂ and V ₃ .
The pitch between the virtual vertical planes V ₂ and V ₃ and the side wall is 2.4. The uppermost ones of these horizontal cooling pipes are installed close to the surface 8 of the fluidized bed created by the rotation of the stirring blades. The method for polymerizing α-olefin using the apparatus of the present invention is illustrated in FIG. α-olefin is supplied from a pipe 13 to a supply port 14 installed near the top of the reaction tank 1 . Hydrogen is generally used as the polymer molecular weight regulator, and is supplied from a supply port 16 via a pipe 15.
When performing copolymerization, other α-olefins are supplied from the supply port 18 via the pipe 17. The catalytically active polymer, previously prepolymerized in a catalyst or other reactor, is fed via line 19 to feed port 2.
0 into the reactor. The heat of polymerization is removed through the cooling pipe 7, and the amount of polymer produced is usually adjusted by monitoring the flow rate of the coolant passed through the cooling pipe and the inlet and outlet temperatures. The polymer, accompanied by unreacted gas, is extracted from the outlet 12 in such a way that the height of the layer of the contents of the reactor is substantially constant, and in a manner that does not cause pressure fluctuations within the reactor. It will be done. Unreacted gas entrained in the polymer is separated from the polymer by a suitable separator and recycled to the reactor. The polymer from which unreacted gas has been separated becomes a powdered product. In some cases, it may be granulated to produce a product. Generally, in the present invention, a so-called high-activity catalyst, which has a sufficiently high catalytic activity, is used as the catalyst. This is because if the catalyst activity is not sufficiently high, there will be a large amount of catalyst residue in the produced olefin polymer, making catalyst decomposition and purification steps necessary. Catalysts included in this group are typically comprised of a combination of a catalyst based on a transition metal compound of groups 1 to 1 of the periodic table and an organometallic compound of a metal of group 1 of the periodic table. The transition metal catalyst may be a compound of a metal such as a titanium compound, a vanadium compound, chromium oxide, molybdenum oxide, or one of these catalysts supported on a magnesium-based support or a support such as alumina, silica, silica-alumina, etc. . As the organometallic compound, an organoaluminum compound is preferable, and in particular, those having the general formula AlR _n X _3-n (R is hydrogen or a hydrocarbon residue having 1 to 10 carbon atoms, and hand,
1 m3) is used. For example, a preferred catalyst for the polymerization of ethylene and propylene is one in which a titanium compound is supported on a magnesium-based carrier such as magnesium halide, and various electron-donating compounds are added as a third component to the above two components. Particularly preferred are the Note that the catalyst that can be used in the apparatus of the present invention is not limited to the catalysts listed above, as long as it can be best implemented by the apparatus of the present invention. α-olefins used in polymerization reactions are generally α-olefins having up to about 12 carbon atoms, but especially ethylene, propylene, butene-1,
Isobutene-1, Pentene-1, Hexene-1,
Those such as 3-methylbutene-1 and 4-methylpentene-1 are preferred. These α-olefins may be homopolymerized, or two or more types of α-olefins may be copolymerized. Typical copolymers are those of ethylene with propylene, butene-1, hexene-1 or 4-methylpentene-1, and propylene with ethylene, butene-1, hexene-1 or 4-methylpentene-1. It is polymerization. Polymerizable monomers other than α-olefin,
For example, copolymerization with diolefins is also possible,
Specifically, 1,4 butadiene, isoprene, 1,
Examples include 4-hexadiene and 4-methyl-1,4-hexadiene. The content of the comonomer is 0.5 to 40% by weight in the resulting copolymer, preferably 0.5%.
The content is preferably ~30% by weight. The reaction conditions in the apparatus of the present invention include at least one α-olefin among the α-olefins to be polymerized.
The temperature and pressure conditions at which the olefin exists substantially in the gas phase and the temperature below the softening point of the resulting polymer are selected. Generally, the temperature is normal temperature to 110℃, the pressure is normal pressure to 45Kg/ ^cm2 , and preferably the temperature is 20℃.
-100°C and pressure ranges from 2 to 40 Kg/ ^cm2 . Although the apparatus of the present invention is usually used as a continuous reactor, it may also be used as a batch reactor. Furthermore, by arranging two or more of the apparatuses in parallel or in series, the polymerization conditions within each apparatus can be changed for operation. An example of producing an α-olefin polymer using the apparatus of the present invention will be shown below. Manufacturing example 1 Shape as shown in Figures 1 and 2, height 1000mm, width 476mm, length 560mm, internal volume approx.
A 270 SUS304 reactor was used. Inside the reactor, 1-inch diameter SUS304 tubes were used as internal coolers, and were arranged in a triangular configuration parallel to the stirring shaft as shown in FIGS. 1 and 2. The mutual spacing between the cooling pipes is 100 mm (pitch 4.0) in the space between both shafts, and there are 4 stages in the height direction, and the mutual spacing is 60 mm (2.4) in the space between each shaft and the side wall. Six stages were installed in the direction. The height of the top horizontal tube is approximately 600 mm from the bottom of the reaction vessel. The number of horizontal pipes installed in this way was 30, and the heat transfer area was 1.34 ^m2 . Temperature-controlled water was passed through this horizontal tube as a coolant. The stirring blade is as shown in FIG. 3, and the length from one tip of the blade to the tip of the other blade 180 degrees apart is 280 mm.
When one set of stirring blades is shown in FIG. 3, four sets of stirring blades are arranged at equal intervals on one rotating shaft. Polyethylene powder, which had been previously dried at 90°C in a nitrogen stream for 4 hours, was charged into the apparatus up to the height of the shaft. The rotational speed of the rotating shaft was 350 rpm, and the direction of rotation was the same as in FIG. 1, in which the contents between the rotating shafts were scraped upward. Next, a catalyst containing magnesium chloride, methyl methacrylate, and titanium trichloride (TiCl ₃ 1/3 AlCl ₃ ) (titanium content: 2.1% by weight) and triethylaluminum were added at a solid catalyst concentration of 2.0 g/
, triethylaluminum was suspended in isopentane at a concentration of 6.0 g/hr and fed at a rate of 500 ml/hr. Ethylene and hydrogen as a chain transfer agent were continuously introduced so that the pressure was 20 atm. The H ₂ /C ₂ H ₄ molar ratio was set to 0.35. The ethylene feed rate was 10.3 Kg/hour. The amount of water passed through the cooling pipe and the water temperature were adjusted so as to maintain the temperature at 85°C. Polymer speed of 10.0Kg/hour, 10000
g/g of catalyst, with a yield of 476,000 g/g-Ti. The operation lasted 10 hours and was completely uneventful. When the inside of the tank was inspected after the completion of operation, no polymer adhesion or lumps were found on the cooling pipes or tank walls. The properties of the obtained polymer were as shown below. Polymer properties melt index
3.5g/10 minutes, (2Kg/cm ² load) Density 0.963g/cm ³ Average particle size 570μ Bulk density 0.396g/cm ³ Comparative example 1 As shown in Figure 4, the mutual spacing of the horizontal cooling pipes was set to 60
mm (pitch 2.4), and six stages were installed in the height direction in a triangular arrangement in the space above the stirring blades. The number of horizontal pipes is 45
In this case, the heat transfer area was 2.01 ^m2 . Polymerization was carried out under exactly the same polymerization conditions as in Production Example 1, but poor stirring occurred about 1 hour after the start of polymerization, and it became difficult to discharge. When polymerization was stopped and the inside of the tank was inspected, many lumps were found between both shafts. Comparative Example 2 As shown in Figure 5, the mutual spacing of horizontal cooling pipes is
The diameter was 100 mm (pitch 4.0), and four stages were installed in the height direction in a triangular arrangement in the space above the stirring blades. The number of horizontal pipes is
18, the heat transfer area was 0.80 ^m2 . Polymerization was carried out under exactly the same polymerization conditions as in Production Example 1, but the heat of polymerization could not be removed successfully, the temperature inside the reaction tank rose to nearly 100°C, and the polymerization was stopped. When the inside of the tank was inspected, many lumps were found. Comparative Example 3 By installing the cooling pipe in Comparative Example 2, the catalyst supply rate could be increased.
Polymerization was carried out under exactly the same polymerization conditions as in Production Example 1, except that the ethylene supply rate was changed to 6.2 kg/hour to 300 ml/hour. The polymer is discharged at a rate of 6.0Kg/hour,
It went smoothly for 10 hours. However, compared to Production Example 1, the polymer production rate was reduced to about 60%. Production example 2 The first powder to be introduced is polypropylene powder, a catalyst containing magnesium chloride, ethyl benzoate, titanium tetrachloride (titanium content is 1.2% by weight) and triethylaluminum is used, and the catalyst feeding rate is 1013ml. /hour and temperature 65℃
Polymerization of propylene was carried out using the same equipment as in Production Example 1 except for the following. Hydrogen as a molecular weight regulator was supplied at a molar ratio of 0.010 to propylene.
Polymer speed: 15.2Kg/hour, 7500g-PP/g-
The catalyst was produced in a yield of 628,000 g-PP/g-Ti. The operation continued for 10 hours, but everything went smoothly.After the operation was completed, the reaction tank was opened and the inside of the tank was inspected.
No polymer adhesion was observed. The properties of the polymer were as shown below. Characteristics of the polymer Melt index 1.5 g/10 min Isotacticity (II) 92.0% Average particle size 380 μ Bulk density 0.413 g/cm ³ Production Examples 3 to 6 Using the same equipment and catalyst as Production Example 1, ethylene and Copolymerization of other α-olefins was carried out.
Table 1 shows the reaction conditions and polymerization results employed.
The polymerization was carried out completely smoothly. Table 2 shows the characteristic values of the obtained polymer.

[Table] *…Molar ratio

【table】 [Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the vicinity of the end face of a cross section perpendicular to the stirring shaft of the device of the present invention, Fig. 2 is a conceptual diagram corresponding to the A-A cross section of Fig. 1, and Fig. 3 is a conceptual diagram of one part of the stirring blade unit.
This is an example. FIGS. 4 and 5 show comparative examples in which the arrangement of horizontal cooling pipes is changed. The correspondence between the main parts illustrated and the symbols is as follows. 1... Reaction tank outer shell, 2, 3... Stirring shaft, 4...
Support, 5... Paddle blade, 6... Stirring blade unit, 7... Cooling tube, 8... Upper surface of fluidized bed, 9,
10...bearing, 11...drive device, 12...discharge port, 13, 15...α-olefin piping, 19...
...Catalyst piping, 14, 16, 18, 20... Supply port.

Claims (1)

[Claims] 1 Homopolymerization and copolymerization of α-olefin,
In a horizontal reaction tank for gas phase polymerization of at least one α-olefin in a substantially gas phase state, a pair of stirring shafts 2 and 3 are provided horizontally and in parallel at the bottom of the reaction tank. Each stirring shaft is provided with stirring blades 6 that can stir up the powdered olefin polymer in the reaction tank by rotation.
The bottom of the reaction tank is made up of a partial cylinder that follows the trajectory drawn by the rotation of the tips of the stirring blades 6 on each stirring shaft, and the polymerization heat is absorbed into the fluidized bed created by stirring. In an apparatus for gas phase polymerization of olefin, which is provided with cooling pipes 7 for removal, a large number of cooling pipes 7 for removing polymerization heat are provided horizontally, and the intervals between the cooling pipes are set so as to maintain the flow of the powdered olefin polymer. An apparatus for vapor phase polymerization of olefin, characterized in that the arrangement is coarse in the ascending part and dense in the descending part. 2. The device according to claim 1, wherein the pitch obtained by dividing the center distance between adjacent cooling pipes 7 by the cooling pipe diameter is 3.5 to 5.0 in the coarse portion and 1.5 to 3.5 in the dense portion. . 3. The rotation of the pair of stirring shafts is in the direction of scraping up the powdered olefin polymer between the two rotating shafts, and the cooling pipe between the surfaces of the pair of stirring shafts is rough, and the outer side of the stirring shaft is Claim 1 that is dense
The device according to paragraph 1 or 2.