JP2002003505A - METHOD FOR PRODUCING alpha-OLEFIN POLYMER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an α-olefin polymer whereby a reaction tank with an equipment for removing the heat in a slurry polymerization or bulk polymerization of α-olefin is used, the uniform mixture performance of slurry in the tank is improved, the retaining volume of solid particle in a reaction vessel is substantially increased, the catalyst efficiency is increased and the required power for stirring can be reduced. SOLUTION: The method wherein the at least one or more polymerization tank are used for the slurry polymerization or bulk polymerization of α-olefin and the polymerization heat developed by the polymerization is removed by utilizing the latent heat caused by vaporization of a vaporizable substance, is characterized in that produced solid particle has a specific particle size, the vaporizable substance in the polymerization tank has a specific superficiality-based vaporizing linear velocity at a specific solid particle concentration in the slurry within the polymerization tank, the vaporizable substance in the slurry within the polymerization tank has a specific bubble content rate and the operation is carried out under the condition of stirring revolution number which may be equal to or higher than the minimum stirring revolution number required to make constant the solid particle concentration in the slurry at a specific position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing α
The present invention relates to a continuous production method in slurry polymerization or bulk polymerization of an olefin polymer, and in particular, reduces all or a part of the reaction heat generated in the polymerization of α-olefin to the latent heat of vaporization of an α-olefin monomer or a hydrocarbon solvent (dispersion medium). The present invention relates to a method for continuously producing an α-olefin polymer that uses heat to remove heat.

[0002]

2. Description of the Related Art α in slurry polymerization or bulk polymerization
-The continuous production method of olefin polymers is roughly classified into a reactor of a double tube type such as a loop reactor and a vertical cylindrical stirring tank type. Methods for improving the productivity of the reactor include (1) a method of reducing the volume of the reactor by operating the solid particles in the slurry inside the reactor at a higher concentration, and (2) retention of the stereoregular catalyst. There is a method of reducing the reactor volume by reducing the time. In the case of the latter method (2), generally, the efficiency of the catalyst (α-olefin polymer per unit catalyst) is reduced by reducing the residence time of the stereoregular catalyst. (1) The method of (1) in which the volume of the reactor is reduced by operating the solid particles in the slurry inside the reactor at a higher concentration is less desirable. In the case of a loop reactor, in order to maintain the operation performance of the slurry circulation pump provided for circulating the slurry inside the reactor, the upper limit of the solid particle concentration in the slurry inside the reactor is limited to a stirring tank. It is generally lower than that of a type reactor. In addition, heat removal equipment is required to remove the amount of heat generated by polymerization, the amount of heat generated from a slurry circulation pump in the case of a loop type reactor, or the amount of heat generated by stirring in the case of a stirred tank type reactor. As a heat removal method, a jacket is attached to the outside of a loop type reactor or a stirring tank, or a reactor in which a plurality of heat removal coil-type baffles are arranged inside the reactor or a slurry of the stirring tank is circulated. It is typically circulated externally by a pump or the like, and the circulation system is provided with equipment for removing heat such as a multi-tube heat exchanger. For example, in the case of a stirred tank reactor, a jacket is attached to the outside, and a plurality of baffles of a heat removal coil type are provided inside, and a heat removal facility using sensible heat and an α-olefin monomer or a hydrocarbon-based It is desirable to evaporate the solvent (dispersion medium) from the reactor and remove the heat using a heat removal facility that utilizes the latent heat of evaporation.

[0003] Generally, a reactor utilizing latent heat of evaporation includes:
A reflux condenser is used that can cool, condense and liquefy the vaporized gas and return it to the reactor. In the above method for producing an α-olefin polymer by slurry polymerization or bulk polymerization, it is necessary to improve the capacity of the above-mentioned heat removal equipment in order to improve the productivity of the reactor. A general method for improving the heat removal capability of the heat removal equipment is to increase the heat transfer area of the heat exchanger of the heat removal equipment. For equipment that removes heat using sensible heat in a loop type reactor or a reactor equipped with a jacket outside the stirring tank or with multiple heat removal coil type baffles inside the reaction tank, It is difficult to increase the heat transfer area of the heat removal equipment without changing the reactor volume because the heat removal equipment is attached to itself.

When the slurry in the stirring tank is externally circulated by a circulating pump or the like and a heat removal system provided with heat removal equipment such as a multitubular heat exchanger in the circulation system, the volume of the reactor is reduced. Although it is possible to improve the productivity without changing the slurry pump, the upper limit of the solid particle concentration in the slurry inside the reactor as in the loop reactor is not used because the slurry pump is used. It needs to be lower than a stirred tank type reactor.

[0005] Further, in order to prevent problems such as adhesion and blockage due to reaction of the slurry to be handled, tubes used in the multi-tube heat exchanger are generally provided in a slurry circulation system. Having an inner diameter of 50 mm or more and a heat transfer coefficient of 200 to 300 kcal / m ² /
[Deg.] C./h, which is as low as about [deg.] C./h. In order to increase the heat transfer area of the heat exchanger, the volume of the heat exchanger becomes excessively large, which is industrially disadvantageous. Because the slurry circulates in the tube,
In order to smoothly transport the solid particles in the slurry, it is necessary to circulate at a specified slurry flow rate or higher, and it is necessary to improve the transport capacity of the slurry circulation pump. You may need the ability.

Further, in the case of a reactor using a stirring tank based on a method utilizing latent heat of vaporization by evaporating an α-olefin monomer or a hydrocarbon solvent (dispersion medium), the volume of the reactor is not changed without changing the volume of the reactor. It is possible to improve the productivity, and the inside diameter of the tube used in the multi-tube heat exchanger attached to the heat removal system has a very small risk of adhesion and blockage like the above-mentioned slurry cooler. ~ 2
Tubes as small as 5 mm can be used and the heat transfer coefficient is 40
0 to 600 Kcal / m ² / ° C./h, which is higher than that of the slurry cooler. When the heat transfer area of the heat exchanger is increased, the volume of the heat exchanger does not become excessive, and the production of the reactor is prevented. It can be said that this is the most suitable heat removal method for improving the heat resistance.

As described above, a method of utilizing the latent heat of vaporization by evaporation of an α-olefin monomer or a hydrocarbon-based solvent (dispersion medium) for all or part of the reaction heat generated in the reaction is disclosed in, for example, -7084, JP-A-62-12
No. 4107, No. 5-74601, No. 5-74
As described in Japanese Patent Publication No. 602 and Japanese Patent Publication No. 7-17705, the method is generally well known.

[0008] The stirring tank in the above-mentioned method utilizing the evaporation of the α-olefin monomer or the hydrocarbon solvent (dispersion medium) comprises:
Generally, a gas-liquid-solid three-phase aeration type stirring tank is used, and a stirring blade often used for the stirring tank includes a plurality of stages of turbine type stirring blades, a plurality of stages of turbine type stirring blades, and three paddle blades (3). Receding wings).

The turbine blades of a plurality of stages are provided with
Six paddles are rotated 30 to 60 with respect to the stirring shaft by rotating the stirring shaft so as to improve the mixing performance of the slurry so that the discharge flow generated from the turbine blade is directed downward.
The three paddle blades (three-way swept wings) have a swept angle of 25 to 50 degrees backward from the axis of the stirring shaft to the tip of the blade in the rotation direction of the shaft. , 10
Those having an ascending angle of ２０20 ° are often used. In the case of a combination of multiple stages of turbine blades and three paddle blades,
Generally, three paddle blades are provided at the bottom of the stirring tank, and a plurality of stages of turbine type blades are provided at regular intervals above the paddle blades.

When a gas is generated by evaporating an α-olefin monomer or a hydrocarbon-based solvent (dispersion medium), the generated gas passes through a slurry portion of a stirring tank and substantially holds a slurry at the upper part of the stirring tank. Not going up to the gas phase. Under the influence of the rising gas, the force exerted on the slurry by the stirring blade (that is, the stirring power) decreases, and as a result, the uniform mixing performance of the slurry decreases. When the uniform mixing performance of the slurry is reduced, a layer having a high solid particle concentration is formed at the lower portion of the slurry layer, and a layer having a low solid particle concentration is formed at the upper portion. Generally, the slurry is withdrawn from the reactor from the lower part of the straight body of the reactor or the bottom of the reactor in many cases. This will reduce the effective residence time of the catalyst and thus the efficiency of the catalyst.

Further, when the gas passage amount is increased or the stirring rotation speed is low, the suspension of solid particles in the slurry is hindered, and a sedimentary layer is formed at the bottom of the stirring tank, and aggregation between particles occurs. It may cause continuous production such as formation of large particles, adhesion and clogging.

[0012] The phenomenon of impairing the uniform mixing performance of the slurry and hindering the floating of the solid particles is caused by the linear velocity (Ug) of the gas passing through the empty column obtained by dividing the amount of gas passing through the slurry layer by the sectional area of the stirring tank. In the slurry, the weight-based solid particle concentration (Ws) in the slurry, and the average particle diameter (d) of the solid particles.
p), the density of solids and liquids in the slurry (ρs and ρ
l), the kinematic viscosity (νl) of the liquid, the mounting position of the stirring blade disposed at the bottom of the stirring tank, and the dimensional ratio (stirring blade diameter / stirring tank diameter).

[0013] The above phenomenon tends to be eliminated by increasing the number of rotations of stirring, but the power required for stirring increases.
Also, the phenomenon that the content of gas in the slurry increases,
It is not industrially favorable. In addition, since the slurry does not substantially exist in the portion of the liquid phase of the stirring tank occupied by the gas, when the stirring tank is used with the same liquid amount, the amount of retained solids is reduced as described above, and the efficiency of the catalyst is reduced. Will be reduced. Generally, when the gas flow rate per unit sectional area of the stirring tank is increased, or the stirring rotation speed is increased to increase the stirring load power, the proportion of the gas in the liquid phase tends to increase.

On the other hand, in order to improve the quality of a product obtained by polymerization of an α-olefin, as represented by impact copolymer grade polypropylene, the average particle size of the solid product particles is conventionally 400 to 600 μm.
In recent years, catalysts having a large product solid particle diameter of 700 to 1500 μm (sometimes 1500 to 2000 μm are also found) are frequently used.

When the product solid particle diameter is increased to 700 to 1500 μm, it is necessary to further increase the number of rotations for stirring in order to uniformly mix the particles and to float the particles, the stirring load becomes excessive, and the gas in the liquid phase becomes large. Occupancy rate has increased,
When the stirring rotation speed of the reaction tank is high, a foaming phenomenon occurs at the interface of the slurry, and the performance of the reflux condenser for liquefying and condensing the evaporant may be significantly reduced, thereby significantly lowering the productivity. ,
It is hard to say that it is difficult to adopt it industrially anymore.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide α-
In slurry polymerization or bulk polymerization of olefins, all or part of the reaction heat generated in the reaction is removed by evaporating an evaporating substance such as an α-olefin or a hydrocarbon solvent (dispersion medium). A reaction vessel having a heat facility is used, and the sedimentation and separation of solid particles in the slurry of the reaction vessel are prevented to improve the uniform mixing performance of the slurry, and an evaporating substance (α-olefin or hydrocarbon solvent (dispersion medium))
The content of gas generated by evaporation of the slurry in the slurry is reduced, the amount of solid particles retained in the reactor is substantially increased, the efficiency of the catalyst can be increased, and the power required for stirring can be reduced. Another object of the present invention is to provide a method for producing an α-olefin polymer which is industrially advantageous.

[0017]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the average particle diameter of the polymerized solid particles, the concentration of the solid particles, the linear velocity of the evaporated substance, and the bubbles of the evaporated substance. By operating under the conditions of stirring rotation speed such that the content ratio, solid particle concentration in the slurry, etc. become specific, and further stirring by a stirring blade of a specific shape, the efficiency of the catalyst is increased and the power required for stirring is reduced. We have found that we can do this and completed the present invention. That is, the present invention uses at least one or more polymerization tanks, and in the presence of a stereoregular catalyst, α-
In the method for producing an α-olefin polymer, the olefin is subjected to slurry polymerization or bulk polymerization, and the heat of polymerization generated in the polymerization is removed using latent heat due to evaporation of an evaporating substance.
The average particle diameter of the solid particles produced by the polymerization is 500 to 2,
2,000 μm, the solid particle concentration in the slurry in the polymerization tank is 20 to 60 wt%, and the evaporation linear velocity (Ug) of the vaporized substance in the polymerization tank based on an empty column is 1.0 to 6. 0 cm / sec, and the bubble content [volume of bubble / (volume of bubble + volume of slurry) × 100] of the vaporized substance in the slurry in the polymerization tank is 40 v.
ol% or less, and further, with respect to the liquid level (H) in the polymerization tank, the lower end of the straight body (lower Tangential)
Line), the solid particle concentration [upper concentration] in the slurry at the position of 0.9H to 1.0H and 0 to
Stirring speed conditions that can be equal to or higher than the minimum stirring speed [particle concentration equilibrium stirring speed (Nus or Nusg)] required for the ratio of the solid particle concentration [lower concentration] in the slurry at the position of 0.1H to be constant. And a method for producing an α-olefin polymer.

Further, according to the present invention, the evaporation linear velocity (Ug) of the vaporized substance in the polymerization tank based on an empty tower is 1.0 to 6.0.
cm / sec, and the power required for stirring (Pgv) per unit volume by stirring in the polymerization tank is 0.5-3.
The method for producing an α-olefin according to the above, wherein the α-olefin is operated at a stirring speed of 0 KW / m ³ .

Further, the present invention relates to a structure of a stirring tank and a stirring blade of a polymerization tank used for polymerization of α-olefin as shown in FIG.
, A rotatable stirring shaft 2 is arranged at the center of a vertical cylindrical stirring tank by a driving source 10 from outside the tank, and the stirring shaft 2 is a distance from the bottom wall surface of the stirring tank to the lower end of the stirring blade (C). And a large bottom paddle blade 1 as shown in FIG. 2, which is disposed at a position where the ratio (C / D) of the diameter (D) of the stirring tank and the diameter (D) is 0.10 or less.
2 and a stirrer blade 3 composed of a lattice blade composed of an arm paddle 14 and a strip 13 extending in a direction perpendicular to the arm paddle 14 at a position higher than the bottom paddle blade 12, and a lower part to an upper part on the side wall of the stirring tank. The above-mentioned method for producing an α-olefin using a stirring tank in which 4 to 12 baffle plates 4 are arranged at intervals along the side wall surface.

Further, the present invention uses the stirring blade 3 having a structure in which the diameter of the upper arm paddle blade is shorter than the diameter of the bottom paddle blade as shown in FIG. This is a method for producing an α-olefin.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below for each item. In the present invention, the α-olefin used as a raw material has 2 to 8 carbon atoms, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene.

In the polymerization of the α-olefin, a stereoregular catalyst or various components constituting the same, such as a solid catalyst component, a cocatalyst, an electron-donating compound if necessary, or a contact product thereof is placed in a polymerization tank. , And α-olefin, and if necessary, hydrogen.

The stereoregular catalyst used in the present invention comprises a solid catalyst component, an organoaluminum compound and, if necessary, an electron donating compound. Here, “consisting of” includes those comprising various suitable components in addition to the above main components.

The stereoregular catalyst of the present invention has essentially no difference in solid catalyst component from this type of conventional stereoregular catalyst. Stereoregular catalysts comprising a solid catalyst component, an organoaluminum compound and, if necessary, an electron donating compound are known (for example, JP-A-56-811, JP-A-58-83006, JP-A-4-218507). JP-A-6-25338, JP-A-57-63311, JP-A-61-213208, and JP-A-62-187706.
JP-A-5-331233, JP-A-5-331123
4, JP-A-63-289004, JP-A-1-319
508, JP-A-52-98706, JP-A-1-54
007 and JP-A-3-72503).

The solid catalyst component used in the present invention contains magnesium, titanium, halogen, and an electron donating compound. Magnesium in the solid catalyst component is
Magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride; alkoxy magnesium such as methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, hexoxy magnesium chloride, octoxy magnesium chloride Allyloxymagnesium such as phenoxymagnesium chloride and methylphenoxymagnesium chloride; alkoxymagnesium such as methoxymagnesium, ethoxymagnesium, isopropoxymagnesium, n-butoxymagnesium, n-octoxymagnesium and 2-ethylhexoxymagnesium ;
Allyloxymagnesium such as phenoxymagnesium and methylphenoxymagnesium; and magnesium carboxylate such as magnesium laurate and magnesium stearate. Incidentally, these magnesium compounds may be used alone,
A mixture may be used.

The titanium in the solid catalyst component is usually Ti (O
R) _g X _4-g (R is a hydrocarbon group, X is a halogen, g is a number satisfying 0 ≦ g ≦ 4), specifically, TiCl ₄ , TiBr ₄ , Titanium halides such as TiI ₄ ; Ti (OCH ₃ ) C
_{l 3, Ti (OC 2 H} 5) Cl 3, Ti (On-C 4 H
_{9) Cl 3, Ti (Oi} -C 4 H 9) Cl 3, Ti (O
CH ₃ ) Br ₃ , Ti (OC ₂ H ₅ ) Br ₃ , Ti (O
_{n-C 4 H 9) Br} 3, Ti (Oi-C 4 H 9) Br 3
Such as trihalogenated alkoxytitanium, Ti (OCH
₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (O
_{n-C 4 H 9) 2} Cl 2, Ti (Oi-C 4 H 9) 2 C
l ₂ , Ti (OCH ₃ ) ₂ Br ₂ , Ti (OC ₂ H ₅ )
_{2 Br 2, Ti (On-} C 4 H 9) 2 Br 2, Ti (O
_{i-C 4} H ₉₎ dihalogenated alkoxy titanium such as _{2 Br 2, Ti (OCH 3} ) 3 Cl, Ti (OC 2 H 5)
_{3 Cl, Ti (On-C} 4 H 9) 3 Cl, Ti (Oi-
C ₄ H ₉ ) ₃ Cl, Ti (OCH ₃ ) ₃ Br, Ti (O
C ₂ H ₅ ) ₃ Br, Ti (On-C ₄ H ₉ ) ₃ Br, T
_{i (Oi-C 4 H9)} 3 monohalogenated alkoxy titanium such as _{Br, Ti (OCH 3) 4} , Ti (OC
_{2 H 5) 4, Ti (} On-C 4 H 9) 4, Ti (Oi-
Tetraalkoxytitanium such as C ₄ H _{9) 4;} or mixtures thereof, or these with aluminum compounds, silicon compounds, sulfur compounds, other metal compounds, hydrogen halides, with a mixture of halogens such as halogen, the A tetravalent titanium compound represented by the general formula Ti (OR) _g X _4-g (R represents a hydrocarbon group, X represents a halogen, and g represents a number satisfying 0 ≦ g ≦ 4); It is usually introduced by halogen or the like.

As the electron donating compound in the solid catalyst component, there can be used a generally known compound used for producing such a solid catalyst component. Generally, oxygen-containing compounds and / or nitrogen-containing compounds are preferred. Examples of the oxygen-containing compound generally include ethers, ketones, esters, and alkoxysilanes. Examples of the nitrogen-containing compound include amines, amides, and nitroso compounds.

As the organoaluminum compound which is a cocatalyst of the stereoregular catalyst, any suitable one can be used. Specifically, (a) trialkyl aluminum,
For example, each alkyl group has 1 to 12 carbon atoms, such as trimethylaluminum, triethylaluminum, trin-propylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, tridodecylaluminum, ( B) Halogen-containing organoaluminum compounds, specifically those in which one or two of the above alkyl groups of the trialkylaluminum are substituted with a halogen such as chlorine or bromine, for example, diethylaluminum chloride, ethylaluminum sesquichloride , (C) a hydride-containing organoaluminum compound, specifically one in which one or two of the alkyl groups of the above trialkylaluminum are substituted with hydrogen, for example, diethylaluminum hydride Chloride, (including aryloxy group) (d) alkoxide-containing organic aluminum compound, one or two alkoxy groups of the alkyl group specifically above trialkylaluminum, especially 1 carbon atoms
Dimethylaluminum methoxide, diethylaluminum methoxide, diethylaluminum ethoxide, diethylaluminum phenoxide, (e) aluminoxane (also referred to as alumoxane), specifically, an alkyl group having a carbon atom Alkyl aluminoxanes having the formulas 1 to 12, such as methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane, can be exemplified. Also, a plurality of these may be used in each group and / or between each group.

The amount of the organoaluminum compound used is not particularly limited, but usually, the molar ratio of aluminum in the organoaluminum compound to titanium in the solid catalyst component is from 0.1 to 10,000, preferably from 10 to 10,000. 500
0, more preferably 50 to 2,000.

As the electron-donating compound used if necessary, those used in this type of stereoregular catalyst can be used. In the present invention, an oxygen-containing compound and / or a nitrogen-containing compound can be mentioned as preferred.

Examples of the nitrogen-containing compound include triethylamine, ethylenediamine, diisopropylamine and di-t-amine.
Butylamine, pyridine, piperidine, 2,2,6,6
Amines such as tetramethylpiperidine and derivatives thereof, and nitroso compounds such as tertiary amines, pyridines and N-oxides of quinolines.

As the oxygen-containing compound, ethers, ketones, esters, and alkoxysilanes can be generally mentioned. (A) As ethers, those having a total of about 2 to 18 carbon atoms, preferably about 4 to 12 carbon atoms in the hydrocarbon residue bonded to ether oxygen and having ether oxygen therein, for example, diethyl ether Ether, dipropyl ether, diethylene glycol dimethyl ether, propylene glycol dimethyl ether,
Ethylene oxide, tetrahydrofuran, 2,2,5
Examples of (b) ketones include 5, -tetramethyltetrahydrofuran, dioxane, and the like, wherein the hydrocarbon residue bonded to the ketone carbonyl group has a total of about 2 to 18 carbon atoms, preferably about 4 to 12 carbon atoms, for example, acetone. , Diethyl ketone, methyl ethyl ketone, acetophenone, and the like, and (c) the esters, wherein the carboxylic acid moiety is aryl or aralkyl carboxylate (the aryl group or aryl moiety is phenyl or lower (about C ₁ -C ₄ ) alkyl and / or lower) Alkyl-substituted phenyl is preferable (about C _{1 to} C ₄ ), the alkyl part of the aralkyl group is preferably about C _{1 to} C ₆ , and the carboxyl group is about _{1 to} C ₆ .
About 3 carbon atoms) or an aliphatic carboxylic acid (where the portion other than the carboxyl group (about 1 to 3) has 1 to 2 carbon atoms).
About 0, preferably about 2 to 12 aliphatic hydrocarbon residues which may contain ether oxygen)
The alcohol moiety has about 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms.
To a degree (including intramolecular esters of the corresponding hydroxy-substituted derivatives of the above carboxylic acids), such as ethyl phenylacetate, methyl benzoate, ethyl benzoate, phenyl benzoate, methyl toluate, ethyl toluate, anisic acid Methyl, ethyl anisate, methyl methoxybenzoate, ethyl methoxybenzoate, methyl methacrylate, ethyl methacrylate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, γ- Butyrolactone, ethyl cellosolve, and the like, (d) alkoxysilanes having at least one alkoxy group (including an aryloxy group, having about 1 to 18 carbon atoms, and preferably about 1 to 4 carbon atoms); The remaining valence of the silicon atom is Group, an aryl group or an aralkyl group (these general descriptions are the same as those described above), tetramethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, t-butyl Trimethoxysilane, phenyltrimethoxysilane, cyclohexyltrimethoxysilane, 1-methylcyclohexyltrimethoxysilane, 1,1,2,2-tetramethylpropyltrimethoxysilane, diethyldimethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxy Silane, diphenyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylethyldimethoxysilane, t-butyl-n-propyldimethoxysilane, t-
Butylisopropyldimethoxysilane, cyclohexylmethyldimethoxysilane, dicyclohexyldimethoxysilane, 1-methylcyclohexylmethyldimethoxysilane, 1,1,2,2-tetramethylpropylmethyldimethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isopropyl Triethoxysilane, t-butyltriethoxysilane, phenyltriethoxysilane, cyclohexyltriethoxysilane, 1
-Methylcyclohexyltriethoxysilane, 1,1,
2,2-tetramethylpropyltriethoxysilane, diethyldiethoxysilane, di-n-propyldiethoxysilane, diisopropyldiethoxysilane, diphenyldiethoxysilane, t-butylmethyldiethoxysilane,
t-butylethyldiethoxysilane, t-butyl-n-
Examples thereof include propyldiethoxysilane, cyclohexylmethyldiethoxysilane, cyclohexylethyldiethoxysilane, 1-methylcyclohexylmethyldiethoxysilane, and 1,1,2,2-tetramethylpropylmethyldiethoxysilane. Of these compounds, piperidines or alkoxysilanes are preferably used, and alkoxysilanes are particularly preferable. The amount of these compounds used is not limited, but is usually from 0 to 1 in terms of the molar ratio to aluminum in the organoaluminum compound used as the cocatalyst.
0, preferably 0-2. Also,
A plurality of electron donating compounds can be selected and used in each group described above and / or between each group.

A solid catalyst component, an organoaluminum compound,
Each catalyst component of the electron-donating compound used as necessary and in the polymerization tank or outside the polymerization tank, in contact with each other in the presence or absence of the monomer to be polymerized, by this contact, the present invention, A stereoregular catalyst is formed. Each of the catalyst components may be independently supplied to the polymerization tank, or may be supplied after arbitrary components are brought into contact with each other.
In this case, the contact method is arbitrary. That is, each component may be contacted simultaneously, or any component may be sequentially contacted. The method for supplying each of these components to the polymerization tank is not particularly limited. Propane, butane, pentane, hexane, heptane, octane, nonane, decane,
It may be supplied by dissolving or suspending it in an inert hydrocarbon solvent such as toluene or xylene, or it may be supplied directly without substantially using these inert hydrocarbon solvents.

According to the present invention, α-olefin is subjected to slurry polymerization or bulk polymerization in the presence of a stereoregular catalyst using at least one polymerization tank, and all or one of the polymerization heat generated in the polymerization is obtained. The part is removed by a method for producing an α-olefin polymer in which heat is removed using latent heat due to evaporation of an α-olefin monomer or a hydrocarbon solvent (dispersion medium).

An example of the manufacturing process of the present invention will be described with reference to the drawings. In FIG. 12, a polymerization tank (stirring tank) 1 has a stirring shaft 2
2, a stirring blade having a large bottom paddle blade 12 and a grid blade composed of an arm paddle 14 and a strip 13 extending perpendicular to the arm paddle 14 above the bottom paddle blade 12. 3, or the crossing angle (θ) between the arm paddle and the strip is 85 to 90 so that the diameter of the upper arm paddle blade 14 is shorter than the diameter of the bottom paddle blade 12 as shown in FIG. °
Which is used for slurry polymerization or bulk polymerization of an α-olefin in the presence of a stereoregular catalyst, and is used for the α-olefin monomer or the hydrocarbon-based solvent evaporated by the heat of reaction. The vapor is cooled by the reflux condenser 5, and the condensate is preheated by the heater 8 through the recovery liquid drum 6 and the recovery liquid pump 7, and is recirculated (recycled) to the stirring tank 1. In the case of bulk polymerization, for example, a polymerization method using liquid propylene white as a medium is used.

In the present invention, the polymerization temperature of the polymerization tank is not particularly limited, but is usually 40 to 120 ° C., preferably 5 to 120 ° C.
Performed at 0-90 ° C. The pressure is not particularly limited, but is usually 1 to 100 atm, preferably 5 to 50 atm. The polymerization is optionally carried out in the presence of hydrogen. There is no particular limitation on the amount of hydrogen supplied to the polymerization tank, and hydrogen necessary for obtaining a desired melt flow rate (hereinafter, referred to as MFR) can be supplied.

As described above, in the polymerization tank 1, all or part of the reaction heat generated by the slurry polymerization or bulk polymerization of the α-olefin is subjected to the α-olefin or hydrocarbon solvent used for the polymerization. It has a heat removal facility for removing the (dispersion medium) by evaporation. As shown in FIG. 1, a polymerization tank (stirring tank) 1 is provided with a rotatable stirring shaft 2 at the center of a vertical cylindrical stirring tank by a drive source 10 from outside the tank. The ratio (C / D) of the distance (C) from the bottom wall of the stirring tank to the lower end of the stirring blade and the diameter (D) of the stirring tank
The arm paddle 14 and a strip 13 extending in a direction perpendicular to the arm paddle 14 at a position higher than the bottom paddle blade 12 as shown in FIG. Or a stirring blade having a configuration in which the diameter of the upper arm paddle blade 14 is shorter than the diameter of the bottom paddle blade 12 as shown in FIG. 3, a stirring tank in which 4 to 12 baffle plates 4 are arranged at intervals from the lower side to the upper side on the side wall of the stirring tank.

The shape of the stirring blade is such that the diameter (di) and the height (h) are di / D = 0.4 with respect to the diameter (D) of the stirring tank.
5 / 0.7, h / D = 0.6-1.2, preferably di / D = 0.5-0.6, h / D = 0.7-1.1, and bottom paddle blade In a stirring blade in which the diameter of the upper arm paddle blade is shorter than the diameter of the upper arm paddle blade, the crossing angle (θ) between the arm paddle and the strip is preferably 80 to 90 °, more preferably 85 to 90 °. Specific examples of the stirring blade having the above-mentioned shape include JP-A-61-200842, JP-A-6-31122, and JP-A-8-252.
A Max Blend blade manufactured by Sumitomo Heavy Industries, Ltd., which is disclosed in Japanese Patent Application Laid-Open No. 444 and JP-A-8-252445, is preferred.

Further, 4 to 12 baffle plates 4 are arranged at intervals on the side wall surface of the stirring tank from the lower part to the upper part along the side wall surface. The width (b) of the arranged baffle plate 4 is in the range of b / D = 0.05 to 0.12 with respect to the diameter (D) of the stirring tank, and the length (L) of the baffle plate is Lower Tangent
The length from the ia line to the liquid level is generally used, but the lower end of the baffle plate is
It may be located above the neg. As the shape of the baffle plate, a plate shape, a columnar shape, and an elliptic column shape are preferably used. Stirring blade and baffle plate dimensions
The shape need not be defined in the above-mentioned range.

In the present invention, the α-olefin is subjected to slurry polymerization or bulk polymerization in a stirring tank using the stirring blade and the baffle plate having the above-mentioned shape, and the particle size of the solid particles formed by the polymerization is 500 to 2 μm. 000 μm, preferably 700
Evaporation of α-olefin monomer or hydrocarbon solvent (dispersion medium) by the heat of reaction when the solid particle concentration in the slurry is in the range of 20 to 60 wt%, preferably in the range of 30 to 50 wt% in the range of 〜1,500 μm. The linear velocity (Ug) of the evaporating gas based on the superficial tower in the stirring tank for the substance is 1.0 to 6.
0 cm / sec range, preferably 2.0-5.0 cm
/ Sec, and the bubble content of the vaporized substance in the slurry in the stirring tank [volume of bubble / (volume of bubble +
(Volume of slurry) × 100] is 40 vol% or less, preferably 5 to 35 vol%, and 0.9 to 0.9% with respect to the liquid level (H) based on the lower Tangental Line in the stirring tank. The solid particle concentration [upper concentration] in the slurry at the position of 1.0 × H and 0 to
Minimum stirring speed required for the ratio of the solid particle concentration [lower concentration] in the slurry at the position of 0.1 × H to be constant [referred to as particle concentration equal stirring speed (Nus or Nu)
sg)], characterized in that it is operated under the condition of stirring rotation speed which can be in the range of 1 or more, preferably 1 to 1.2.

The solid particles to be produced have a particle size of 50
If it is less than 0 μm, it is difficult to improve the quality of the product obtained by polymerization of α-olefin, and if the particle diameter of the solid particles to be produced exceeds 2000 μm, the particle concentration balance stirring speed becomes excessive, and as a result Requires excessive stirring power and is economically disadvantageous.

When the solid particle concentration in the slurry is 20 wt.
%, The amount of solid particles retained in the stirring tank decreases, and the catalyst's efficiency decreases due to a substantial reduction in the residence time of the catalyst. If the concentration of the solid particles in the slurry exceeds 60 wt%, the viscosity of the slurry sharply increases due to the increase in the concentration of the solid particles, and the stirring power increases and the mixing performance deteriorates.

Further, when the linear velocity of the evaporative gas on the basis of the empty tower is lower than the lower limit (1.0 cm / sec), it is necessary to reduce the polymerization amount of the α-olefin monomer when using a stirring tank having the same capacity. Alternatively, in order to obtain the same amount of polymerization of the α-olefin monomer, it is necessary to increase the inner diameter (size) of the stirring tank, which is economically disadvantageous. On the other hand, the evaporative gas linear velocity based on the superficial tower is the upper limit (6.0 cm / sec).
Is exceeded, bubbling at the gas-liquid interface (Foamin
g) To cause a phenomenon or increase the amount of particles jumping out from the liquid surface, causing a decrease in the performance of the reflux condenser for heat removal, and in order to prevent the particles from jumping out,
It is economically disadvantageous because it is necessary to increase the size of the empty tower portion of the stirring tank. When the bubble content of the evaporating substance in the slurry in the polymerization tank exceeds the upper limit (40 vol%), the catalyst particles are not retained in the bubble portion, and the residence time of the catalyst is substantially reduced. This is not preferable because it causes a problem of lowering the overall efficiency. Further, if the solid particle concentration in the slurry is less than the minimum stirring rotation speed required to be constant, a difference in solid particle concentration occurs between the upper part and the lower part of the slurry held in the stirring tank, and the solid particle concentration in the upper part Is decreased, and the residence time of the catalyst is substantially reduced, which causes a problem of lowering the catalyst efficiency, which is not preferable.

According to the present invention, in the slurry polymerization or bulk polymerization of α-olefin, all or a part of the reaction heat generated in the reaction is converted to the α-olefin or hydrocarbon-based solvent (dispersion medium) used for the polymerization. Gas-liquid-represented by continuous polymerization method of α-olefin polymer that removes heat by evaporation
It is an object of the present invention to provide a method for selecting a stirring blade and setting a stirring rotation speed in a solid three-phase ventilation stirring tank. In particular, the particle concentration of the solid is as high as 30 to 60 wt%, the average particle diameter of the solid particles is as large as 700 to 1,500 μm, and the gas-based superficial base linear velocity is from 2.0 to 6.0 cm / sec. It is an object of the present invention to provide a method of selecting a stirring blade having a good balance between the uniform mixing of particles and the content of bubbles, and a method of setting the number of rotations for stirring under conditions where the linear velocity is high and the suspension and uniform mixing of particles are extremely disadvantageous.

Further, stirring per unit volume by stirring
Required power is 0.5 to 3.0 KW / m ³The range of the slurry
Mixing performance is good and desirable in terms of catalyst efficiency.
Required power is 0.5KW / m³If less than the slurry in the stirring tank
The catalyst efficiency is greatly reduced due to the reduced mixing performance of
3.0 KW / m³Exceeds the required power for stirring
Economically disadvantageous and increases the bubble content.
The catalyst efficiency is also lowered.

As described above, in the present invention, in the slurry polymerization or bulk polymerization of α-olefin, all or a part of the reaction heat generated in the reaction is converted to α-olefin or hydrocarbon solvent ( The present invention provides a method for selecting a stirring blade and setting a stirring rotation speed in a gas-liquid-solid three-phase aeration stirring tank represented by a continuous polymerization method for an α-olefin polymer that removes heat by evaporation of a dispersion medium). is there.

FIG. 5 shows an example of a two-stage turbine blade + three paddle blades (hereinafter referred to as a multi-stage blade), and FIG. 6 shows an example of a stirring blade (hereinafter referred to as a large blade) of the present invention. If the stirring rotation speed is low even in a non-vented state where gas does not pass,
In the portion of the stirring tank holding the slurry, the solid particle concentration in the slurry at the upper and lower portions of the slurry layer may not be in a uniform mixing state.

That is, the upper portion of the slurry layer has a low solid particle concentration, and the lower portion has a high solid particle concentration. In this phenomenon, the difference between the concentration of the upper part and the concentration of the lower part is eliminated by sequentially increasing the rotational speed of the stirring, and the concentration of the solid particles in the upper and lower portions becomes almost uniform.

The solid particle concentration of the slurry layer becomes almost uniform.
The minimum stirring speed required for
If we call it the number of turns (Nus), the relationship is based on our study.
It was found that the following equation was used. Nus = K · ν^−0.25[G · (ρs−ρl) / ρ
l]^0.4・ Dp^{0. 47}・ Ws^0.22/ Di^0.8  However, in the above formula, each symbol is as follows. Nus: Particle concentration equal stirring time under gas non-aeration condition
Number of turns [sec^-1] K: Constant determined by the shape of the arranged stirring blade ν: Kinematic viscosity of liquid [m²/ Sec] ρs: density of solid [kg / m³] Ρl: density of liquid [kg / m]³Ws: concentration by weight of solid particles [wt%] dp: particle diameter of solid particles [m] di: diameter of arranged blades;
Average wing diameter [m]

Here, in order to compare the constant K, ν− ^0.25 · [g · (ρs−ρl) / ρl] excluding the constant K in the above equation and the actually measured particle concentration balance stirring speed. ^0.4
FIG. 7 shows the relationship between the calculated values of the formula of dp ^0.47 .Ws ^0.22 / di ^0.8 for the multistage blade and the large blade.

Also, in a gas-liquid-solid three-phase aeration tank in which gas is passed, it is necessary to correct Nus obtained by the above equation in order to consider the influence of gas ventilation.
This phenomenon is caused by the aeration of gas, which causes buoyancy to act on the particles.However, the agitation phenomena caused by the aeration of the agitating blades lowers the power of the agitation load. It is considered that the influence of the lowering of the stirring power appears more remarkably than the buoyancy exerted on the water, and can be expressed by the following equation.

Nusg = Nus · [1 + K ′ · (Ug / Ut)]^α  However, in the above formula, each symbol is as follows. Nusg: Particle concentration equal stirring time under gas aeration conditions
Number of turns [sec^-1K ', [alpha]: constant determined by the shape of the stirring blade disposed at the bottom Ug: superficial base gas linear velocity of the ventilation gas in the stirring tank
[M / sec] Ut: Static sedimentation speed of solid particles [m / sec]

In many experiments by the present inventors, K, K ', and α of the multi-stage blade and the large blade can be used to estimate the particle-concentration equilibrium stirring rotation speed by using the following numerical values.

[0054]

[Table 1]

As described above, the value of the constant K of the large blade is smaller than that of the multi-stage blade, the particle concentration equilibrium stirring speed in the non-ventilated state is small, and the large blade has a lower stirring speed than the multi-stage blade. It has been found that it is possible to equilibrate the particle concentration.

The above description is an evaluation based on the rotational speed of the particle concentration equilibrium stirring, and it is generally necessary to compare the required stirring power. The required stirring power at the particle concentration equal stirring rotation speed under non-aeration can be generally obtained by the following equation.

Pw = K · g · Ut · Ws^0.66  However, in the above formula, each symbol is as follows. Pw: per unit weight at the particle concentration balance rotation speed
Power required for stirring [KW / kg] Pw = P / V / ρ_av  K: constant [-] determined by the shape of the stirring blade g: acceleration of gravity; 9.81 [m / sec]²Ut: Static sedimentation velocity of solid particles [m / sec] Ws: Weight-based concentration of solid particles [wt%]

When comparing the constant (K) between the multi-stage blade and the large blade, the large blade is superior even when evaluated by the required power as follows.

[0059]

[Table 2]

Similarly, as a result of comparing and examining the change in the content of bubbles in the slurry in a state where the gas is passed through the multistage blade and the large blade, as shown in FIG. 8 and FIG. It was found that the rate was affected by the linear velocity of the ventilation gas and further varied depending on the rotational speed of the stirring. FIG. 8 shows an example of an experimental result of a multi-stage wing, and FIG. 9 shows an example of an experimental result of a large wing.

When gas is passed, the slurry density is reduced due to inclusion of gas in the slurry, and in the case of a multistage blade, in particular, the phenomenon of containing air bubbles at the rear of the upper turbine type blade (that is, Cavity ), The power required for stirring is reduced. The present inventors have obtained the following equations for estimating the power required for stirring under gas aeration conditions using a number of experimental results.

Pgv = K · ρ_aν・ Ug^(1-β)/
[Fr^1.2・ D^0.5]^(-Β)  However, in the above formula, each symbol is as follows. Pgv: Power required for stirring under aeration per unit volume [W /
m³K: Constant ρ depending on shape and combination of stirring blades_aν: Average density of slurry [kg / m³Ug: linear velocity of gas flow based on the empty tower of the stirring tank [m / sec]
c] Fr: stirring fluid number; Fr = n²・ Di / g n: stirring speed [sec]^-1Di: diameter of the wings arranged; in the case of multi-stage wings, multiple stages that were cast
Average diameter [m] of the wing of the g: acceleration of gravity; 9.81 [m / sec]²D: diameter of stirring tank [m] β: constant K and β of the multistage blade and large blade are compared as follows.
You.

[0063]

[Table 3]

As an example, FIG. 10 shows the relationship between the above-mentioned equation for estimating the aeration and stirring power of large wings and the value measured by experiment.

Next, the content of the gas in the slurry in a state where the gas is passed (that is, gas hold-up;
The result of obtaining an equation for estimating εg) is described. As mentioned above,
8 and 9 that the gas holdup is related to the ventilation gas linear velocity and the power required for stirring.

8 and 9, when compared with the multi-stage blade (FIG. 8), the large blade (FIG. 9) has a small change in the bubble content due to a change in the stirring rotation speed (that is, the power required for stirring). It can be seen that the rise in the bubble content is small in the high linear velocity region where the gas ventilation linear velocity is 4 cm / sec or more.

From the results of many experiments conducted by the present inventors, it was found that when the concentration of solid particles in the slurry was increased, the gas hold-up was reduced, and that the particle size of the solid particles in the slurry was slightly affected. As a correlation equation for gas hold-up, the following estimation formula was obtained, taking into account the effect of slurry concentration and the size of solid particles, based on a model that considers energy dissipation in turbulent conditions.

Εg / (1−εg) = K · [(Pg / Qg) / ｛ρ_aν・ (G ・ μ_aν/ Ρ_{a ν} )^2/3｝]^α・ [Qg / (g · di⁵)^1/2]^β・ [G ・ di²・ Ρ_aν / Σ]^1/5・ [(Μ_aν/ Ρ_aν)²/ (G · di³)]^2/45・ [Ρ_aν / (Ρ_aν−ρ_g)] ・ (Ρ_g/ Ρ_aν)^1/15・ (Μ_aν/ Μ_l)^−1/4 ・ (1 + Ut / U_turb)^-1/10  However, in the above formula, each symbol is as follows. K, α, β: coefficient εg: bubble content rate in slurry [gas / (gas + slurry)
-)] [-] Pg: Power required for stirring under ventilation [W] Qg: Gas ventilation [m]³/ Sec] ρ_aν: Average slurry density [kg / m³] Μ_aν: Average viscosity of slurry [kg / m / sec] μ_l: Liquid viscosity [kg / m / sec] ρ_g: Gas density [kg / m³] Σ: surface tension [N / m] di: diameter of the arranged blade; in case of a multi-stage blade, a plurality of arranged blades
Average diameter [m] of the wing of the g: acceleration of gravity; 9.81 [m / sec]²Ut: Static sedimentation velocity of solid particles [m / sec]_turb: Turbulence characteristic velocity 1.4 · (Np · n³・ Di
⁵/ V · dp)^{(1 / 3)} [M / sec] Np: power number n: stirring speed [sec]^-1V: Volume of slurry layer in stirring tank [m³Dp: average particle diameter of solid particles [m]

In the multi-stage wing and the large wing used by the present inventors,
It is possible to estimate the bubble content by using the following K, α, and β.

[0070]

[Table 4]

When replaced by the form of εg / (1−εg) ∝Pg ^m · Qg ⁿ , m and n are as follows, and it can be seen that the large blade is hardly affected by the stirring power and the amount of ventilation gas.

[0072]

[Table 5]

As an example, FIG. 1 shows the relationship between the equation for estimating the bubble content by the above-mentioned ventilation and the measured value in an experiment for a large wing.
1 is shown.

The empirical formula for estimating the power required for stirring and the power required for stirring under gas aeration has been described above, but the present invention is not limited to these.

As described above, in the method for producing an α-olefin polymer by slurry polymerization or bulk polymerization,
All or part of the reaction heat due to polymerization is substantially contained in a bubble-containing slurry in a reaction tank equipped with a heat removal facility utilizing latent heat of vaporization by evaporation of the α-olefin monomer or hydrocarbon solvent (dispersion medium). It is important to improve the uniform mixing performance of the slurry and to reduce the content of bubbles in the slurry in order to increase the amount of solid particles retained and increase the efficiency of the catalyst. By using each of the above estimation formulas shown by the present invention, the internal state of the reactor is predicted,
Appropriate design becomes possible.

[0076]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The following Examples and Comparative Examples were performed using the following reaction apparatus and measurement apparatus. (1) Reactor In a reactor as shown in FIG. 12, a reflux condenser for condensing and liquefying the evaporated gas, a drum holding the condensed liquid, a pump for supplying the recovered liquid to the reactor again, and A heater for heating and evaporating the liquid is provided as an accessory equipment. The inside diameter is 750 mm, the height is 1370 mm, and the capacity is 0.
A stirring shaft is provided at the center of a 66 m ³ vertical stirring tank, and the distance from the bottom wall surface of the stirring tank to the lower end of the blade is 8 mm.
At the position of 0 mm, in FIG.
When expressed using the symbols, di = 420 mm, h = 6
00 mm, b1 = 220 mm, b2 = 354 mm, b3
= 26mm, R1 = 210mm, R2 = 173mm, R
When large wings of 3 = 120 mm and R4 = 95 mm (described in Examples and Comparative Examples 1 to 3) are provided, and some of Comparative Examples (Comparative Examples 4 to 6) are expressed using symbols in FIG. di = 4
36mm, w = 65mm, receding angle about 30 °, rising angle about 1
3 paddle wings of 5 ° are arranged, and about 320
mm = di = 300mm, w = 60mm,
Two stages of turbine-type blades with 1 = 76 mm and four paddle blades having an inclination angle of about 45 ° downward were provided.

The stirring shaft was set at 0 to 36
It is rotated by an inverter motor (10) whose rotation speed can be changed within a range of 0 r / m. In addition, a double-tube slurry cooler (9) for cooling and eliminating bubbles contained in the slurry by evaporation of gas is provided in a line for extracting the reaction slurry from the bottom of the stirring shaft to the downstream processing equipment. Placed.

(2) Measuring Apparatus and Method A torque meter (21) for measuring the power required for stirring and a photoelectric tachometer (22) for measuring the number of rotations are attached to the outside of the tank of the stirring shaft. Have been. An orifice type differential pressure flow meter (2) is provided between the stirring tank and the reflux condenser to measure the linear evaporation rate of the gas based on the empty tower inside the stirring tank.
3) is provided.

As a means for measuring the concentration of solid particles in the slurry inside the reactor, the lower Tangent of the trunk of the reactor is used.
A sampling tube (24) and a valve are provided at a position inserted 50 mm and 750 mm above the ial line and 100 mm from the side wall of the stirring tank, and sampling is performed.
The solid particle concentration was determined. Further, a radiation type density meter (25) was installed downstream of the double tube type slurry cooler installed in the bottom extraction line of the stirring tank, and the solid density in the slurry was determined by measuring the slurry density. The content (εg) of bubbles in the slurry inside the reactor was determined by measuring two radiation type densitometers (25) at approximately the same height as the above-mentioned sampling tube arrangement position, using a double line at the bottom extraction line of the stirring tank. A radiation type densitometer (25) is arranged on the upstream side of the tube cooler, and the average density of the slurry containing bubbles is measured. The bubble content rate was calculated. _{ρ slurry = 100 / {[solid} ] / ρ s +
(100− [solid]) / ρ _l εg = (ρ _{slurry −ρ av} ) / (ρ _slurry
−ρ _g ) × 100 However, in the above formula, each symbol is as follows. ρ _slurry : average density of slurry (liquid and solid) not containing bubbles [solid]: concentration of solid particles in slurry not containing bubbles ρ _s : density of solid ρ _l : density of liquid ρ _aν : measured with radiation density meter Density ρ _g including gas bubbles: Gas density of evaporated gas

Example 1 With the large wings attached to the reaction tank shown in FIG.
0.44m³(L / D = 1.16), polymerization temperature 70 ° C.,
Pressure 32.5kg / cm²G, stirring speed 200r /
m, gas evaporation linear velocity 6.0 cm / sec (evaporation amount 7.0
ton / h), solid catalyst supply l. 10 g / h, prop
A polypropylene bag with a feed rate of 110 kg / h
Luc continuous polymerization was performed. In this operation, the required movement of stirring
The force is 1.14 KW (Pgv = 2.6 KW / m ³)
And polypropylene by sampling above and below the reactor
The particle concentration in both the upper and lower parts was almost uniform at 45 wt%.
The bubble content calculated by the radiation densitometer is 3
0.0 vol%. Particles obtained by continuous polymerization are flat.
The average particle size is 800 μm and the catalyst efficiency is 44,000 g
Propylene / g-catalyst, polypropylene average
At a production rate of 50 kg / h. Liquid
Atactic polypropylene, a by-product of polymerization, is added to propylene.
A part of the ren is dissolved, and the liquid
Is estimated to be 2.0-2.5 centipoise.
The calculated particle concentration balance stirring speed under the operating conditions is 1
It was 66 r / m.

Example 2 A catalyst having a slightly larger particle diameter than the catalyst used in Example 1
The evaporation linear velocity of gas was set to 4.0 cm / sec (evaporation
Same as Example 1 except that the amount was reduced to 4.7 ton / h)
Under the conditions, bulk continuous polymerization of polypropylene was performed. this
In operation, the power required for stirring is 1.18 KW (Pgv
= 2.7KW / m ³) And samplers above and below the reactor
The concentration of polypropylene particles in both upper and lower parts
45 wt%, almost uniform
The calculated bubble content was 27.0 vol%. Communicating
The average particle size of the particles obtained by the continuation polymerization is 1,000 μm,
The efficiency of the medium is 45,000 g-polypropylene / g-catalyst
The average production rate of polypropylene is 50 kg / h.
Obtained at the site. Liquid propylene is a by-product of polymerization
Dissolve some of the atactic polypropylene
And the viscosity of the solution is 2.0 to 2.5
It is estimated to be centipoise.
The particle rotation rate of the particles was 170 r / m.

Example 3 To increase the production capacity, the stirring speed was reduced to 190 r / m and the catalyst supply rate was 1.47 g / h.
The bulk continuous polymerization of polypropylene was performed under the same conditions as in Example 2 except that the concentration of the substantial polypropylene particles in the reaction tank was increased. In this operation, the power required for stirring was 1.18 KW (Pgv = 2.7 KW / m ³ ), and the polypropylene particle concentration by sampling at the top and bottom of the reaction tank was almost uniform at 60 wt% in both the upper and lower parts. The bubble content calculated by the densitometer is 2
It was 5.0 vol%. The average particle size of the particles obtained by continuous polymerization is 1,000 μm, and the efficiency of the catalyst is 45,000 g.
Polypropylene / g-catalyst, polypropylene being obtained at an average production rate of 66.3 kg / h. Liquid propylene dissolves a part of atactic polypropylene by-produced by polymerization, and from the dissolved concentration, the viscosity of the liquid is estimated to be 2.0 to 2.5 centipoise. The calculated particle concentration balance stirring rotation speed was 180 r / m.

Example 4 A bulk continuous polymerization of polypropylene was carried out under the same conditions as in Example 2 except that a catalyst having a larger particle diameter was used than the catalyst used in Example 2. In this operation, the power required for stirring was 1.18 KW (Pgv = 2.7 KW / m ³ ), and the polypropylene particle concentration by sampling at the top and bottom of the reaction tank was almost uniform at 45 wt% in both the upper and lower parts. The bubble content calculated by a densitometer was 26.6 vol%. The average particle size of the particles obtained by continuous polymerization is 1,500 μm, and the efficiency of the catalyst is 45,000.
g-polypropylene / g-catalyst, polypropylene being obtained at an average production rate of 50 kg / h. Except that the average particle diameter of the product polymer was increased to 1,500 μm, almost the same results as in Example 2 were obtained. Liquid propylene dissolves a part of atactic polypropylene produced as a by-product of polymerization, and the viscosity of the liquid is determined to be 2.0 to 2.5 centipoise based on the dissolved concentration. Calculated particle concentration balance stirring speed at 19
It was 5 r / m.

Example 5 In order to see the dependence of the production capacity on the polypropylene concentration, the amount of the catalyst fed was changed from 1.1 g / h to 0.6 in Example 4.
Bulk continuous polymerization of polypropylene was carried out under the same conditions as in Example 4, except that the feed rate was reduced to 5 g / h and the propylene supply rate was lowered to 100 kg / h. In this operation, the power required for stirring was 1.04 KW (Pgv = 2.4 KW / m ³ ), and the concentration of polypropylene particles by sampling at the top and bottom of the reaction tank was almost uniform at 30 wt% in both the upper and lower parts. The bubble content calculated by the densitometer is 2
9 vol%. The particles obtained by continuous polymerization had an average particle size of 1,500 μm, the catalyst efficiency was 45,000 g-polypropylene / g-catalyst, and the polypropylene was obtained at an average production rate of 30 kg / h. The results were almost the same as those of Example 4, except that the production rate decreased corresponding to the decrease in the catalyst supply amount and the polypropylene particle concentration. Liquid propylene dissolves a part of atactic polypropylene produced as a by-product of polymerization, and the viscosity of the liquid is determined to be 2.0 to 2.5 centipoise based on the dissolved concentration. The calculated particle concentration balanced stirring rotation speed in the above was 193 r / m.

Example 6 Example 5 for grasping the limit of the polypropylene particle diameter
A catalyst with a larger particle size was used for the catalyst used in
Except for the above, the bulk conditions of polypropylene were the same as in Example 5.
Continuous polymerization was performed. In this operation, the power required for stirring is
1.18 KW (Pgv = 2.7 KW / m ³) And anti
Polypropylene particle concentration by sampling above and below the tank
The degree is almost uniform at 30 wt% for both the upper and lower parts,
The bubble content calculated from the linear densitometer is 28.5 v
ol%. Particles obtained by continuous polymerization have an average particle size
1,800 μm, catalyst efficiency 43,500 g-polyp
Propylene / g-catalyst, polypropylene on average 2
Obtained at a production rate of 9 kg / h. Product polymer flat
The average particle size has been increased to 1,800 μm,
Although a decrease in the rate was observed, a result almost equivalent to that of Example 5 was obtained.
Obtained. Attack by-produced by polymerization in liquid propylene
Part of the tick polypropylene is dissolved,
Liquid viscosity is 2.0-2.5 centipoise
Estimated particle concentration under these operating conditions.
The balance stirring rotation speed was 200 r / m.

Comparative Example 1 Example 6 for grasping the limit of the polypropylene particle diameter
A catalyst with a larger particle size was used for the catalyst used in
Except for the above, the bulk conditions of polypropylene were the same as in Example 6.
Continuous polymerization was performed. In this operation, the power required for stirring is
1.18 KW (Pgv = 2.7 KW / m ³) And anti
Polypropylene particle concentration by sampling above and below the tank
As for the degree, the upper part is 10 wt%, the lower part is 30 wt%
Polymer particles do not exist and the radiation density
The bubble content calculated from the meter is 29.5 vol%
there were. The average particle size of the particles obtained by continuous polymerization is 2,10
0 μm, catalyst efficiency is 34,000 g-polypropylene
/ G-catalyst, and polypropylene averages 23 kg /
h of production rate. Average particle size of product polymer
Increased to 2,100 μm, resulting in reduced catalyst efficiency and production
A decrease in performance was noted. Heavy liquid propylene
Dissolve some of the atactic polypropylene that is
The viscosity of the liquid is 2.0
~ 2.5 centipoise, estimated under these operating conditions
The calculated particle concentration balance stirring speed was 210 r / m.
Was.

Comparative Example 2 In order to recover the decrease in productivity in Comparative Example 1, Comparative Example 1
And the stirring speed was increased to 250 r / m.
Except for the above, bulk bulk polypropylene was prepared under the same conditions as in Comparative Example 1.
Continuous polymerization was performed. In this operation, the power required for stirring is
2.01 KW (Pgv = 4.6 KW / m ³) And anti
Polypropylene particle concentration by sampling above and below the tank
The degree is almost uniform at 30 wt% for both the upper and lower parts.
The bubble content calculated from the ray density meter is 30.0.
vol%. Average particle size of particles obtained by continuous polymerization
Is 2,300 μm, and the catalyst efficiency is 42,500 g-poly.
Propylene / g-catalyst, polypropylene on average
Obtained at a production rate of 28 kg / h. Product of polymer
The average particle diameter has been increased to 2,300 μm,
No decrease in production capacity
Significant increase in agitation load power due to increase
Was. Attack, which is a by-product of polymerization in propylene, which is liquid
Dissolves a part of
Liquid viscosity is 2.0-2.5 centipoise
It is estimated that the calculated particle concentration
The impingement rotation speed was 220 r / m.

Comparative Example 3 To increase the polymer particle concentration to 70 wt% in order to further increase the production capacity, the calculated particle concentration equilibrium stirring speed was 219 r / m. / M, and the bulk continuous polymerization of polypropylene was performed under the same conditions as in Example 3 except that the catalyst supply amount was increased to 1.72 g / h. In this operation, the power required for stirring is 2.81 KW (Pgv = 6.5 KW / m ³ ).
The polypropylene particle concentration obtained by sampling at the top and bottom of the reaction tank was almost uniform at 70 wt% in both the upper and lower parts, and the bubble content calculated by a radiation type densitometer was 15 vol%. The average particle size of the particles obtained by continuous polymerization is 1,550 μm, and the efficiency of the catalyst is 50,000 g-
Polypropylene / g-catalyst, polypropylene being obtained at an average production rate of 77 kg / h. Although the efficiency and production capacity of the catalyst could be improved, the agitation load power was unusually high and industrially difficult, so that the conditions could not be adopted.

Comparative Example 4 In order to confirm the influence of the stirring blade, a liquid volume of 0.44 m ³ (L / D =
1.16), polymerization temperature 70 ° C, pressure 32.5 kg / cm
² G, stirring speed 360 r / m, gas evaporation linear velocity 6.0
The bulk continuous polymerization of polypropylene was performed under the conditions of cm / sec (evaporation amount: 7.0 ton / h), solid catalyst supply amount: 0.83 g / h, and propylene supply amount: 83 kg / h. In this operation, the power required for stirring is 1.62 KW (Pgv =
3.7 KW / m ³ ), the polypropylene particle concentration by sampling at the top and bottom of the reactor was 38 wt% at the top,
The lower portion had a slight concentration difference of 45 wt%, and the bubble content calculated by a radiation densitometer was 40.0 vol%. The average particle size of the particles obtained by continuous polymerization is 800 μ
m, efficiency of the catalyst is 44,500 g-polypropylene / g
-As a catalyst, polypropylene was obtained at an average production rate of 38 kg / h. Since the agitation load power is high, which is industrially disadvantageous, and the content of bubbles is high, the production capacity is reduced by about 25% as compared with Example 1. Liquid propylene dissolves a part of atactic polypropylene by-produced by polymerization, and from the dissolved concentration, the viscosity of the liquid is estimated to be 2.0 to 2.5 centipoise. The calculated particle concentration balance stirring rotation speed is 360 r /
m.

Comparative Example 5 After the stirring rotation speed was reduced from 360 r / m to 300 r / m.
Outside is the bulk of polypropylene under almost the same conditions as Comparative Example 4.
Continuous polymerization was performed. In this operation, the power required for stirring
Is 0.96 KW (Pgv = 2.2 KW / m ³)
Polypropylene particles by sampling above and below the reactor
The remarkable concentration is 9wt% in the upper part and 45wt% in the lower part.
Includes bubbles with a difference, calculated from the radiation density meter
The rate was 37.0 vol%. Particles obtained by continuous polymerization
The average particle size of the particles is 740 μm, and the efficiency of the catalyst is 35,000.
g-polypropylene / g-catalyst, polypropylene
Was obtained at an average production rate of 30 kg / h. Stirring negative
Although the loading power was in the steady range, the amount of the catalyst
Efficiency was reduced by about 20% and production capacity was reduced by about 40%.
Liquid propylene has an atactic
Part of the polypropylene is dissolved and dissolved
From the concentration, the viscosity of the liquid was estimated to be 2.0 to 2.5 centipoise.
Calculated at this operating condition
The stirring rotation speed was 355 r / m.

Comparative Example 6 The same procedure as in Comparative Example 4 was carried out except that the catalyst used in Example 4 was used.
The bulk continuous polymerization of polypropylene was performed under the same conditions. This
, The required power for stirring is 1.58 KW (Pg
v = 3.6 KW / m ³) And sump above and below the reactor
The concentration of polypropylene particles by the ring is 8wt at the top
%, The lower part has a remarkable concentration difference of 45 wt%.
The content of air bubbles calculated by a densitometer is 39.5 vol.
%Met. The average particle size of the particles obtained by continuous polymerization is 1,
350 μm, catalyst efficiency 33,000 g-polypropylene
Len / g-catalyst, polypropylene on average 30k
g / h. High stirring load power
In contrast to Example 4, the efficiency of the catalyst is about 2
It decreased by 5% and production capacity decreased by about 40%.

[0092]

EFFECT OF THE INVENTION In a polymerization method in which an α-olefin monomer or a hydrocarbon solvent (dispersion medium) is evaporated by slurry polymerization or bulk polymerization of α-olefin to remove the heat of polymerization or stirring heat by latent heat of vaporization, a method of vaporizing gas is used. In order to maintain the balance between the content of bubbles in the slurry and the uniform mixing performance of the solid particles of the slurry, the efficiency of the catalyst in the polymerization reactor is improved by using an effective stirring blade and setting the stirring speed to an appropriate value. The power required for stirring was reduced.

[Brief description of the drawings]

FIG. 1 shows a reaction vessel of the present invention.

FIG. 2 shows an example of a stirring blade used in the present invention.

FIG. 3 shows an example of a stirring blade used in the present invention.

FIG. 4 shows three paddle blades and a turbine blade used for comparison.

FIG. 5 shows an example of a measurement result of a relationship between a stirring rotation speed and a particle concentration in a reaction tank in a multistage blade.

FIG. 6 shows an example of a measurement result of a relationship between a stirring rotation speed and a particle concentration in a reaction tank in a large blade.

FIG. 7 shows the relationship between the measured value of the particle concentration balance stirring speed and the estimated calculated value.

FIG. 8 shows an example of measurement results of the relationship between the gas velocity and the bubble content in a multistage blade.

FIG. 9 shows an example of a measurement result of a relationship between a gas flow rate and a bubble content rate in a large wing.

FIG. 10 shows the relationship between measured values and estimated calculated values of aeration / stirring power in large wings.

FIG. 11 shows a relationship between a measured value and a calculated value of the bubble content due to ventilation in a large wing.

FIG. 12 schematically shows a process chart relating to the manufacturing method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 stirring tank 2 stirring shaft 3 stirring blade 4 baffle plate 5 reflux condenser 6 recovery liquid drum 7 recovery liquid pump 8 heater 9 double tube heat exchanger 10 electric motor 11 boss 12 bottom paddle 13 strip 14 arm battle 21 torque meter 22 Photoelectric tachometer 23 Orifice type differential pressure flow meter 24 Sampling tube 25 Radiation density meter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08F 2/02 C08F 2/02 2/08 2/08 F term (Reference) 4G078 AA13 AA21 AB11 BA05 CA01 CA08 DA30 4J011 DA02 DA04 DB16 DB19 DB23 FA01 FA06 FB04 FB07 FB11 FB16 HA03 HB01 HB03 HB05 HB07 HB16 HB18

Claims (4)

[Claims] 1. Using at least one or more polymerization tanks,
In the presence of a stereoregular catalyst, a method for producing an α-olefin polymer in which α-olefin is subjected to slurry polymerization or bulk polymerization and heat of polymerization generated in the polymerization is removed by utilizing latent heat due to evaporation of an evaporating substance. The average particle diameter of the solid particles produced by the polymerization is in the range of 500 to 2,000 μm, and the concentration of the solid particles in the slurry in the polymerization tank is 20 to 60.
wt%, and the evaporation linear velocity (Ug) of the vaporized substance in the polymerization tank based on an empty tower is 1.0 to 6.0 cm / s.
ec, the bubble content of the evaporating substance in the slurry in the polymerization vessel [bubble volume / (bubble volume + slurry volume) × 100] is 40 vol% or less, and the polymerization vessel The solid particle concentration [upper concentration] in the slurry at a position of 0.9H to 1.0H with respect to the lower end of the straight body portion (lower Tangential Line) and 0 to 0.1H with respect to the liquid level height (H) in the inside. The operation is carried out under a stirring rotation speed condition that can be equal to or higher than the minimum stirring rotation speed [particle concentration equilibrium stirring rotation speed (Nus or Nusg)] required to keep the ratio of the solid particle concentration [lower concentration] in the slurry at the position of (1) constant. A method for producing an α-olefin polymer, comprising: 2. A linear evaporation speed (Ug) of the vaporized substance in a polymerization tank based on an empty tower in a range of 1.0 to 6.0 cm / sec, and a stirring per unit volume by stirring in the polymerization tank is required. power (PGV) of claim 1 operating at a stirring speed of conditions is 0.5~3.0KW / ^{m 3} α-
Olefin production method. 3. The structure of the stirring tank and the stirring blade of the polymerization tank used for the polymerization of α-olefin can be rotated at the center of the vertical cylindrical stirring tank in FIG. The ratio (C / D) of the distance (C) from the bottom wall of the stirring vessel to the lower end of the stirring blade and the diameter (D) of the stirring vessel becomes 0.10 or less. As shown in FIG. 2, a grid wing composed of a large bottom paddle wing 12 and an arm paddle 14 above the bottom paddle wing 12 and a strip 13 extending in a direction perpendicular to the arm paddle 14 is provided. A stirrer equipped with a stirrer blade (3) and using a stirrer in which 4 to 12 baffle plates (4) are arranged at intervals along the side wall from the lower part to the upper part on the side wall of the stirrer.
Or the method for producing an α-olefin according to claim 2. 4. The structure of the stirring blade 3 according to claim 3 is shown in FIG.
The method for producing an α-olefin according to any one of claims 1 to 3, wherein the stirring blade 3 is shaped such that the diameter of the upper arm paddle blade is shorter than the diameter of the bottom paddle blade.