JP2002003507A - 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 outflow of an uncondensed gas by short path is inhibited when the gas is backed to a liquid phase of a polymerization tank. SOLUTION: The method wherein the polymerization tank equipped with multi-impeller stirrer is used for the slurry polymerization or bulk polymerization of α-olefin and a developed polymerization heat is removed by utilizing the latent heat caused by vaporization of a vaporizable substance, is characterized in that the tip position and spouting direction of a monotreme nozzle and its position to a turbine impeller blade are specific when the gas in a reflux condenser contained in the equipment is backed to the liquid phase of the tank by the nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an α-
The present invention relates to a continuous production method for slurry polymerization or bulk polymerization of an olefin polymer, and more particularly to a continuous production method for an α-olefin polymer in which heat of reaction generated in the polymerization of α-olefin is removed by utilizing latent heat of vaporization of an evaporable substance. .

[0002]

2. Description of the Related Art α in slurry polymerization or bulk polymerization
-The types of reactors for continuous production of olefin polymers are roughly classified into a double tube type such as a loop type reactor and a vertical cylindrical stirring tank type. Methods for improving the productivity of the reactor include (1) a method of reducing the reactor volume by operating the solid particles in the slurry in the reactor at a higher concentration, and (2) a residence time of the stereoregular catalyst. There is a method to reduce the reactor volume by lowering the reactor volume. However, in the case of the latter method (2), if the residence time of the stereoregular catalyst is generally reduced, the efficiency of the catalyst (the production amount of α-olefin polymer per unit catalyst) is lowered, which is not desirable. The method (1) in which the reactor volume is reduced by operating the solid particles in the slurry at a higher concentration is desirable.

[0003] In the case of a loop reactor, the upper limit of the solid particle concentration in the slurry in the reactor is limited in order to maintain the operation performance of a slurry circulation pump for circulating the slurry in the reactor. It is generally lower than. In addition, heat removal equipment for removing the heat generated from the slurry circulation pump in the case of the loop type reactor or the heat generated by stirring in the case of the stirred tank type reactor is required along with the reaction heat generated by the polymerization. . As a heat removal method, a jacket is attached to the outside of the loop reactor or the stirring tank, or a reactor in which a plurality of heat removal coil-type baffles are disposed inside the reaction tank or the 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 heat removal such as a multi-tube heat exchanger.

[0004] For example, in the case of a stirred tank type reactor, a heat removal facility utilizing sensible heat, in which a jacket is attached to the outside and a plurality of heat removal coil type baffles are provided inside, and an α-olefin monomer is provided. An effective method is to evaporate an evaporating substance such as a solvent or a hydrocarbon-based solvent (dispersion medium) in the reactor and use heat removal equipment utilizing the latent heat of evaporation in combination.
Generally, a reflux condenser capable of cooling, condensing and liquefying an evaporated gas and returning it to the reactor is used in a reactor utilizing latent heat of evaporation. 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 a heat removal facility is to increase the heat transfer area of a heat exchanger of the heat removal facility. 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 circulation pump, and a heat removal system with equipment for heat removal such as a multi-tube heat exchanger is used in the circulation system, the volume of the reactor is reduced. It is possible to increase productivity without making any changes,
In order to use a slurry pump, the upper limit of the solid particle concentration in the slurry inside the reactor, as in the loop reactor,
It is necessary to lower the temperature as compared with a stirred tank type reactor not using a slurry pump.

A multi-tube heat exchanger provided in the slurry circulation system is generally 50 mm in diameter in order to prevent problems such as adhesion and blockage due to reaction of the slurry to be handled. The one having the above inner diameter is used, and the heat transfer coefficient is 200 to 300 Kcal / m ² / ° C.
/ H). The method of increasing the heat transfer area of the heat exchanger in order to increase the heat removal capacity is disadvantageous industrially because the volume of the heat exchanger becomes excessively large. Furthermore, since the slurry circulates in the tube, it is necessary to circulate at a speed higher than the general slurry flow rate in order to smoothly transport the solid particles in the slurry, and it is necessary to improve the transport capacity of the slurry circulation pump, Further, the slurry pump may need to have a capacity exceeding the industrial production limit.

Further, in the case of a reactor using a stirring tank by a method utilizing latent heat of evaporation by evaporation of an evaporating substance such as an α-olefin monomer or a hydrocarbon solvent (dispersion medium), the volume of the reactor is not changed. It is possible to improve the productivity of the reactor, and the inside diameter of the tube used for the multi-tube heat exchanger attached to the heat removal system also has a very high risk of adhesion and blockage as in the aforementioned slurry cooler. Since it is small, a tube having a small diameter of 15 to 25 mm can be used, and the heat transfer coefficient is also 400 to 600 Kcal / m ² / ° C./h.
When the heat transfer area of the heat exchanger is increased as compared with the slurry cooler, the capacity of the heat exchanger does not become excessive, and the heat removal method most suitable for improving the productivity of the reactor is used. It can be said that.

As described above, a continuous method for producing an α-olefin polymer by slurry polymerization or bulk polymerization of a heat removal system utilizing latent heat of vaporization due to evaporation of a vaporized substance is suitably used industrially. The stirring tank of the above-described method utilizing the evaporation of an evaporating substance such as an α-olefin monomer or a hydrocarbon solvent (dispersion medium) is generally called a gas-liquid-solid three-phase aeration stirring tank, It is known to use a plurality of turbine-type stirring blades in a tank. Further, in order to improve the mixing performance of the slurry, the discharge flow generated from the turbine type blade is directed upward or downward with the rotation of the stirring shaft in order to improve the mixing performance of the slurry. What is inclined 30 to 60 degrees with respect to the stirring axis is preferably used.

[0010] The gas generated by the evaporation of the evaporant due to the heat of reaction passes through the slurry portion of the stirring tank, rises to the gas phase section substantially free of slurry at the top of the stirring tank, and is introduced into the reflux condenser. In the vessel, gas that is easily condensed is liquefied, gas-liquid separated in the next drum, and non-condensed gas is pressurized by a blower and returned to the polymerization tank, while condensate is also self-pressurized or pressurized by a pump. A heat removal system that returns to the polymerization tank is used. The configuration of the system is not particularly limited as long as the purpose of condensing and removing heat is achieved. The condensed liquid is basically returned to the polymerization tank, but may be used for other purposes such as flushing for cleaning.
The pressure of the non-condensable gas is increased by a blower and is basically returned to the polymerization tank. However, a part of the non-condensable gas may be recycled to the condenser depending on the concentration of the non-condensable gas such as hydrogen in the polymerization tank.

[0011] Of the non-condensable gas, those returned to the polymerization tank are desirably returned to the entire or part of the liquid phase in order to maintain gas-liquid equilibrium in the polymerization tank. In this case, it becomes a factor that causes a process problem. That is, when the gas is returned to near the liquid level, the gas cannot be sufficiently mixed with the gas generated by evaporation of the evaporant due to the heat of reaction because the residence time of the gas in the liquid phase is short, and the polymerization is not performed. Vapor-liquid equilibrium in the tank is impaired. At the same time, since the gas is not sufficiently dispersed, the rise of the gas is localized near the liquid surface, the liquid surface oscillates, and the droplets increase, and the polymer accompanies the droplets and condenses. In such a case, there arises a problem that the coefficient of fouling of the heat transfer surface in the condenser increases and the performance of the condenser decreases. The above-mentioned phenomenon of lowering gas dispersibility tends to be eliminated by increasing the number of rotations of stirring, but the power required for stirring increases, which is not industrially preferable. It is also conceivable to attach a sparger (porous dispersion tube) at the tip of the nozzle in order to improve gas dispersibility, but equipment having a complicated shape in the polymerization tank may cause the formation of lumps, and Since a higher head is required for the blower, it is industrially preferable to recycle the non-condensable gas to the polymerization tank using a simpler nozzle having a simpler structure and a smaller pressure loss.

On the other hand, when the gas is returned to the vicinity of the bottom of the polymerization tank, the gas dispersibility tends to be improved due to an increase in the residence time of the gas, but generally, the slurry is extracted from the reactor. Is often performed from the lower part of the straight body of the reactor or the bottom of the reactor, and since the return position of the gas approaches the slurry discharge position of the polymerization tank, the extracted slurry contains a large amount of light boiling components. The gas may be mixed. In such a case, when the slurry is withdrawn from the polymerization tank by a pump, a slight pressure drop or temperature rise causes bubbles in the slurry liquid, causing cavitation of the pump and stable production. Will be impaired.

[0013]

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). When using a reaction vessel having a heat facility and returning non-condensable gas in the reflux condenser included in the heat removal facility to the liquid phase of the polymerization vessel, the dispersibility of the gas in the liquid phase is substantially increased. Accordingly, it is an object of the present invention to provide an industrially advantageous method for producing an α-olefin polymer, which can prevent the gas from flowing out in the gas phase of a polymerization tank or into a slurry liquid withdrawn from the polymerization tank through a short pass.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to achieve the above object, and as a result, the position of the nozzle when returning the non-condensed gas through the single-hole nozzle, the direction of the nozzle blowing, etc. By specifying the diameter of the paddle blades and turbine blades used as stirring blades,
The present inventors have found that the dispersibility of the gas can be improved, and have completed the present invention.

That is, according to the present invention, an α-olefin is subjected to slurry polymerization or bulk polymerization in the presence of a stereoregular catalyst using a polymerization tank provided with multi-stage stirring blades, and a polymerization solution is withdrawn using a pump. Also, in the method for producing an α-olefin polymer in which the generated heat of polymerization is removed by using latent heat due to evaporation of an evaporating substance, a part of the gas evaporated from the upper part of the polymerization tank is liquefied in a reflux condenser, When the pressure of the non-condensed gas is increased by a blower and returned to the liquid phase portion of the polymerization tank by a single-hole nozzle, the tip of the nozzle is located at the same height as or above the lowest turbine blade height, and the height difference (H) And the ratio (H / D) of the polymerization tank to the inner diameter (D) of the polymerization tank is in the range of 0 to 0.3,
In addition, the blowing direction has a swing angle (β) of −30 to +30 degrees with respect to the stirring axis direction, and 0 to 60 with respect to the horizontal direction.
A method for producing an α-olefin polymer, characterized in that blowing is performed at an inclination angle (α) of degrees, and the blades of the lowermost turbine blade are positioned on an extension thereof.

Further, according to the present invention, the stirring blade comprises a paddle blade and a turbine blade protruding from a stirring shaft, and the paddle blade is disposed at a lower end of the stirring shaft. The swept angle (γ) with respect to the rotation direction of the shaft increases in the tip direction of the wing, and the swept angle at the tip is in the range of 25 to 50 °,
It consists of three paddle blades having a rising angle (δ) of 10 to 20 °, and the ratio (d1 / D) of the diameter (d1) of the paddle blade to the diameter (D) of the polymerization tank is 0.5 to 0. 0.75, and the ratio (b1 / d1) of the paddle blade width (b1) to the paddle blade diameter (d1) is in the range of 0.1 to 0.2. The turbine type blade is provided above the paddle blade, and the size thereof is such that the ratio (d2 / D) of the diameter (d2) of the turbine type blade to the diameter (D) of the stirring tank is 0.4-0. 6, the ratio (b2 / d2) of the width (b2) of the turbine blade to the diameter (d2) of the turbine blade is in the range of 0.15 to 0.25, and the length of the blade of the turbine blade. (I) and the diameter (d2) of the turbine blade (I2)
/ D2) is in the range of 0.2 to 0.3, and the blade of the turbine type blade has an inclination angle (θ) of 30 to 60 °.
The paddle blade has a ratio (C / D) of the distance (C) between the lower end of the blade and the bottom of the stirring tank and the diameter (D) of the stirring tank. The method for producing an α-olefin polymer according to the above, wherein the α-olefin polymer is provided at a position of 2 or less.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, an α-olefin is subjected to slurry polymerization or bulk polymerization in the presence of a stereoregular catalyst using a polymerization tank provided with multi-stage stirring blades. In the present invention, the α-olefin used as a raw material has 2 to 18 carbon atoms, for example, ethylene, propylene, 1-
Butene, 1-pentene, 1-hexene, 1-octene and the like. In the polymerization of the α-olefin, a stereoregular catalyst or various components constituting the same, for example, a solid catalyst component, a cocatalyst, an electron-donating compound if necessary, or a contact product thereof is added to the polymerization tank. It is carried out by continuously feeding olefins 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, the term “consisting of” includes those containing various suitable components in addition to the above main components. The stereoregular catalyst according to the present invention has essentially no difference in solid catalyst components from conventional stereoregular catalysts of this kind. 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-58-83006).
-218507, JP-A-6-25338, JP-A-5
7-63311, JP-A-61-213208, JP-A-62-187706, JP-A-5-331233,
JP-A-5-331234, JP-A-63-289004
JP-A-1-319508, JP-A-52-9870
No. 6, JP-A-1-54007 and JP-A-3-72
No. 503).

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 such as methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, hexoxy magnesium chloride, octoxy magnesium chloride Magnesium halide; allyloxy magnesium halide such as phenoxy magnesium chloride, methylphenoxy magnesium chloride; alkoxy such as methoxy magnesium, ethoxy magnesium, isopropoxy magnesium, n-butoxy magnesium, n-octoxy magnesium and 2-ethylhexoxy magnesium Magnesium; Ants such as phenoxymagnesium and methylphenoxymagnesium Alkoxy magnesium; magnesium laurate, can be obtained from such carboxylates of magnesium such as magnesium stearate. In addition, these magnesium compounds may be used alone or as a mixture.

The titanium in the solid catalyst component is usually Ti (O
R)_gX_4-g(R is a hydrocarbon group, X is a halogen, g is
A tetravalent titanium compound represented by the formula: 0 ≦ g ≦ 4)
Object, specifically, TiCl₄, TiBr₄, TiI₄What
Which titanium tetrahalide; Ti (OCH₃) C
1₃, Ti (OC₂H₅) C1₃, Ti (On-C₄H
₉) C1₃, Ti (Oi-C₄H₉) C1₃, Ti (O
CH₃) Br₃, Ti (OC₂H₅) Br₃, Ti (O
n-C₄H₉) Br₃, Ti (Oi-C₄H₉) Br₃
Trihalogenated alkoxytitanium such as Ti; OCH
₃)₂C1₂, Ti (OC₂H₅)₂C1₂, Ti (O
n-C₄H₉)₂C1₂, Ti (Oi-C₄H₉)₂C
1₂, Ti (OCH₃)₂Br₂, Ti (OC₂H₅)
₂Br₂, Ti (Oi-C₄H₉)₂Br₂Jiha such as
Logenated alkoxy titanium; Ti (OCH₃)₃C1,
Ti (OC₂H₅)₃C1, Ti (On-C₄H₉)₃
C1, Ti (Oi-C₄H₉)₃C1, Ti (OC
H₃)₃Br, Ti (OC₂H₅) ₃Br, Ti (On
-C₄H₉)₃Br, Ti (Oi-C₄H₉)₃Br
Which monohalogenated alkoxytitanium; Ti (OC
H₃)₄, Ti (OC₂H₅)₄, Ti (On-C₄H
₉)₄, Ti (Oi-C₄H₉)₄Such as tetraarco
Xtitanium; or a mixture or a mixture thereof
Aluminum compounds, silicon compounds, sulfur compounds,
Mixing with other metal compounds, hydrogen halide, halogen, etc.
Depending on the product, the halogen is represented by the above general formula Ti (OR)_g
X_4-g(R is a hydrocarbon group, X is a halogen, g is 0 ≦ g
≦ 4), a tetravalent titanium compound represented by
It is common to introduce hydrogen halides, halogens, etc.
It is.

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, tri-n-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, for example, chlorine, bromine or the like, for example, diethylaluminum chloride, ethylaluminum sesquioxide Chloride, (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 Dolides, (d) alkoxide-containing organoaluminum compounds, specifically those in which one or two of the above-mentioned trialkylaluminum alkyl groups are alkoxy groups (including aryloxy groups), especially those having about 1 to 8 carbon atoms Such as dimethylaluminum methoxide, diethylaluminum methoxide, diethylaluminum ethoxide, diethylaluminum phenoxide, (e) aluminoxane (also referred to as alumoxane), specifically, an alkyl group having 1 to 12 carbon atoms. Certain alkylaluminoxanes, for example,
Methylaluminoxane, ethylaluminoxane, isobutylaluminoxane and the like can be mentioned. Also,
These can also be used in plural within each group and / or between each group.

The amount of the organoaluminum compound used is not particularly limited. 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. The electron-donating compound used as necessary also
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.

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 nitrogen-containing compound include amines, amides, and nitroso compounds, and specifically, triethylamine,
Ethylenediamine, diisopropylamine, di-t-butylamine, pyridine, piperidine, 2,2,6,6-
Amines such as tetramethylpiperidine and derivatives thereof, and tertiary amines, pyridines and quinolines N
-Nitroso compounds such as oxides.

As the oxygen-containing compound, generally, ethers
, Ketones, esters, alkoxysilanes
Can be (A) As ethers, charcoal that binds to ether oxygen
The hydride residue has a total carbon number of about 2 to 18, preferably 4 to
About 12 with ether oxygen inside
For example, diethyl ether, dipropyl ether
Ter, diethylene glycol dimethyl ether, propylene
Lenglycol dimethyl ether, ethylene oxide,
Tetrahydrofuran, 2,2,5,5-tetramethylte
Trahydrofuran, dioxane, etc.
Is a hydrocarbon residue that binds to a ketone carbonyl group
Has a total carbon number of about 2 to 18, preferably about 4 to 12.
Stuffs, such as acetone, diethylketone, methylethyl
Ketone, acetophenone, etc. with (c) esters
The carboxylic acid moiety is aryl or aralkyl
Rubonic acid (aryl group or aryl moiety is phenyl or
Or low (C₁~ C ₄Degree) alkyl and / or low
Grade (C₁~ C₄Degree) Alkoxy-substituted phenyl is preferred
And the alkyl portion of the aralkyl group is C₁~ C₆Degree
Preferably, about 1 to 3 carboxyl groups are preferred.
) Or an aliphatic carboxylic acid (carboxyl group (1 to
Portions other than about 3) have about 1 to 20 carbon atoms, preferably
Is a fat that may contain 2 to 12 ether oxygens
Is an aromatic hydrocarbon residue), and the alcohol moiety is
Those having about 1 to 8 carbon atoms, preferably about 1 to 4 carbon atoms (the above
Of the corresponding hydroxy-substituted derivatives of carboxylic acids
Ter), for example, ethyl phenylacetate, benzoate
Methyl benzoate, ethyl benzoate, phenyl benzoate, tol
Methyl ylate, ethyl toluate, methyl anisate,
Ethyl varnish, methyl methoxybenzoate, methacrylic acid
Methyl, ethyl methacrylate, dimethyl phthalate, lid
Diethyl phthalate, dipropyl phthalate, dibutyl phthalate
, Diisobutyl phthalate, dihexyl phthalate, γ-
Butyrolactone, ethyl cellosolve, etc.
Coxysilanes include alkoxy groups, (aryl
It contains a xyl group and has about 1 to 18 carbon atoms.
But preferably about 1 to 4).
The remaining valence of the i-atom is an alkyl group, an aryl group or
Is an aralkyl group (the general description of which is
Are the same), tetramethoxysilane, ethyl
Rutrimethoxysilane, n-propyltrimethoxysila
, Isopropyl trimethoxy silane, t-butyl tri
Methoxysilane, phenyltrimethoxysilane, cyclo
Hexyltrimethoxysilane, 1-methylcyclohexyl
Rutrimethoxysilane, 1,1,2,2-tetramethyl
Propyltrimethoxysilane, diethyldimethoxysila
, Di-n-propyldimethoxysilane, diisopropyl
Rudimethoxysilane, diphenyldimethoxysilane, t
-Butylmethyldimethoxysilane, t-butylethyldi
Methoxysilane, t-butyl-n-propyldimethoxy
Silane, t-butylisopropyldimethoxysilane,
Clohexylmethyldimethoxysilane, dicyclohexyl
Rudimethoxysilane, 1-methylcyclohexylmethyl
Dimethoxysilane, 1,1,2,2-tetramethylpro
Pilmethyldimethoxysilane, ethyltriethoxysila
, N-propyltriethoxysilane, isopropyl
Liethoxysilane, t-butyltriethoxysilane,
Phenyltriethoxysilane, cyclohexyltriethoxy
Sisilane, 1-methylcyclohexyltriethoxysila
1,1,2,2-tetramethylpropyltriethoxy
Sisilane, diethyldiethoxysilane, di-n-propyl
Rudiethoxysilane, diisopropyldiethoxysila
, Diphenyldiethoxysilane, t-butylmethyldi
Ethoxysilane, t-butylethyldiethoxysilane,
t-butyl-n-propyldiethoxysilane, cyclohexane
Xylmethyldiethoxysilane, cyclohexylethyl
Diethoxysilane, 1-methylcyclohexylmethyldi
Ethoxysilane, 1,1,2,2-tetramethyl propyl
And methyldiethoxysilane.

Of these compounds, piperidines or alkoxysilanes are preferably used, and alkoxysilanes are particularly preferably used. The amount of these compounds is not limited, but is usually used so that the molar ratio to aluminum in the organoaluminum compound used as a cocatalyst is 0 to 10, preferably 0 to 2. In addition, a plurality of electron donating compounds can be selected and used within each of the above groups 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 catalyst component may be independently supplied to the polymerization tank, or may be supplied after contacting any of the components.
In this case, the contact method is arbitrary. That is, each component may be contacted simultaneously, or arbitrary components 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.

The polymerization of the α-olefin of the present invention is carried out using a multi-stage stirring blade, and can be carried out, for example, using the apparatus shown in FIG. In FIG. 1, a polymerization tank 1 has a multi-stage stirring blade, for example, paddle blades 3 (a plurality of blades, particularly three blades) and a turbine type blade 4 on a stirring shaft 2. Sulfur polymerization or bulk polymerization of olefins is performed, and α-olefins and other feedstock evaporated from the upper part by the heat of reaction are first introduced into the condenser 6 to liquefy easily condensable gas in the vessel, and the next drum Gas-liquid separation is performed at 7, and the non-condensable gas is pressurized by the blower 8 and returned to the polymerization tank 1, and the condensate is also self-pressured or pumped up and returned to the polymerization tank 1. The configuration of the system is not particularly limited as long as the purpose of condensing and removing heat is achieved. In the case of bulk polymerization, for example, a polymerization method using liquid propylene itself as a medium is used.

In the present invention, the polymerization temperature in the polymerization tank 1 is not particularly limited, but is usually 40 to 120 ° C., preferably 50 to 90 ° C. The pressure is not particularly limited, but is usually 1 to 100 atm, preferably 5 to 50 atm.
m. 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 supplied to the α-olefin or hydrocarbon solvent supplied to the polymerization. It has a heat removal facility for removing the (dispersion medium) by evaporation. As shown in FIG. 1, a multi-stage stirring blade, for example, a paddle blade 3 is provided on a stirring shaft 2 for stirring the inside of the polymerization tank.
And a turbine blade 4. The stirring shaft 2 is located at the center of the polymerization tank 1 and is disposed in the vertical direction, and multi-stage (multi-stage) stirring blades are provided in the vertical direction.

The paddle blade 3 is arranged at the lower end of a multi-stage stirring blade provided on the stirring shaft 2 and has a shape of
As shown in FIG. 2, a paddle blade 3a is projected from the stirring shaft 2 in a radial direction, and a retreat angle (γ) of the tip portion is 2.
Three paddle blades 3 having a rising angle (δ) of 5 to 50 ° and a rising angle (δ) of 10 to 20 ° and generally called three-way swept wings are preferably used. Also, paddle wing 3
The ratio (d1 / D) of the diameter (d1) of the paddle blade 3 to the diameter (D) of the stirring tank is 0.5 to 0.75.
And the ratio (b1 / d1) of the width (b1) of the paddle blade 3a to the diameter (d1) of the paddle blade 3 is 0.1.
It is desirably in the range of -0.2.

The turbine blades 4 are provided above the paddle blades 3 in one or more stages, and their structures are provided so as to project in a direction perpendicular to the stirring shaft 2 as shown in FIG. Turbine blades 4b that are inclined at equal intervals in the circumferential direction are fixed to the disc-shaped support plate 4a. Ratio (d2 / D) of the diameter (d2) of the turbine blade and the diameter (D) of the polymerization tank 1
Is in the range of 0.4 to 0.6, and the width of the turbine blade (b2)
(B2 / d2) between the diameter and the diameter (d2) of the turbine blade in the range of 0.15 to 0.25, and the turbine blade 4b
The ratio (I / d2) between the width (I) of the blade and the diameter (d2) of the blade is in the range of 0.2 to 0.3.
It is preferable that four to six blades are provided in a state where the turbine blades are inclined at an inclination angle (θ) of 30 to 60 ° so that the discharge flow generated from the turbine blades is directed downward.

The paddle blade 3 has a position (C / D) where the ratio (C / D) of the distance (C) between the lower end of the blade and the bottom of the polymerization tank 1 and the diameter (D) of the polymerization tank 1 is 0.2 or less. Further, 4 to 12 baffle plates 5 are arranged on the side wall surface of the polymerization tank 1 from the lower part to the upper part along the side wall surface at intervals in the circumferential direction.

As shown in FIG. 4, the tip position of the gas injection nozzle 9 on the gas outlet side is the same as or higher than the height of the lowermost turbine blade, and the height difference (H) and the inner diameter (D ) And (H / D) in the range of 0 to 0.3,
In addition, the blowing direction has a swing angle (β) of −30 to +30 degrees with respect to the stirring axis direction, and 0 to 60 with respect to the horizontal direction.
It blows out at an angle of inclination (α) and is located such that the trajectory of the blades of the lowermost turbine blade is present on its extension. Further, the position of the contact point between the extension line in the blowing direction and the orbit of the turbine blade is not particularly limited. In FIG. 1, the gas injection nozzle 9 has a pipe inserted vertically downward from the upper mirror portion of the polymerization tank. However, the invention is not limited to this. For example, if the nozzle tip position and the blowing direction are satisfied, for example, The nozzle may be introduced into the polymerization tank from the body of the polymerization tank. Further, in FIG. 4, there is no particular limitation on the distance (X) when the turbine blade and the tip of the nozzle are closest due to the rotation of the turbine blade, but the ratio (X / d2) to the blade diameter (d2) is not limited. It is desirable to be in the range of 0.05 to 0.2. Although there is no particular limitation on the nozzle hole diameter, it is preferable that the nozzle linear velocity be 50 m / sec or less when the blower is operated at the maximum throughput.

According to the method of the present invention, the gas blown out of the single-hole nozzle first collides with the turbine blade and is divided into smaller bubbles. The buoyancy of the reduced gas decreases,
Due to the synergistic effect of the downward discharge flow of the turbine blades and the stirring of the paddle blades, they are dispersed throughout the polymerization tank without making a short pass to reach the upper liquid surface in a short time. Further, due to the reduction in the particle diameter of the gas and the increase in the residence time, the chance of contact with the reaction liquid or the gas generated by the evaporation of the evaporant due to the heat of the reaction increases, and the homogenization in the polymerization tank is promoted.

The gas blowing direction from the single-hole nozzle is
In addition to the turbine blade direction described in the present invention, vertical downward,
Vertically upward, horizontal and stirring rotation direction, and horizontal and stirring rotation reverse direction are roughly classified. The stirring rotation direction refers to the case of blowing out in the stirring rotation direction in a horizontal direction and tangential to the side wall of the polymerization tank, and the opposite direction of the stirring rotation is 180 degrees. If the above gas is blown vertically upward, in the stirring rotation direction, or in the stirring rotation reverse direction, the gas is not sufficiently dispersed in the turbine blade or the paddle blade,
In addition, in the liquid phase portion of the polymerization tank, the gas rises without being sufficiently mixed with the gas generated by the evaporation of the evaporating substance due to the reaction heat, and reaches the gas phase portion. In such a state, since it is cooled and condensed in the condenser, the temperature is lower than the reactor liquid temperature,
In addition, the gas containing a large amount of light-boiling components is short-passed and reaches the gas phase, so that the gas-liquid equilibrium in the polymerization tank is impaired. At the same time, since the gas is not sufficiently dispersed, the rise of the gas is localized near the liquid surface, the liquid surface oscillates, and the droplets increase, and the polymer accompanies the droplets and condenses. In such a case, there arises a problem that the coefficient of fouling of the heat transfer surface in the condenser increases and the performance of the condenser decreases.

On the other hand, when the jetting direction is vertically downward, if the nozzle height is the same, the gas dispersion time increases due to an increase in the residence time of the gas as compared with the vertical upward, stirring rotation direction, and stirring rotation reverse direction. However, when the jetting speed is high, the slurry is generally withdrawn from the reactor from the lower part of the straight body of the reactor or from the bottom of the reactor. There is a high possibility that the gas containing a large amount of light-boiling components will be mixed into the extracted slurry. In such a case, when the slurry is withdrawn from the polymerization tank by a pump, a slight pressure drop or temperature rise causes bubbles in the slurry liquid, causing cavitation of the pump and stable production. Operating conditions are limited to suppress cavitation due to damage and additional equipment for defoaming is required.

[0037]

EXAMPLES The effects of the present invention will be described with reference to the results of model tests shown in the following examples and comparative examples, but the present invention is not limited to these examples.

The following examples and comparative examples were carried out using a stirrer and a measuring device described below. (1) Stirring device The vertical stirring tank 10 shown in FIG. 5 has an inner diameter (D) of 310 mm,
The height is 520mm and the inside is 10cm by CMC at room temperature.
The water adjusted to cp is L / D =
It has been thrown to a height of 1.0. A stirring shaft is provided at the center position of the stirring tank 10, and the stirring shaft 2 is positioned at a distance of 15 mm from the bottom wall surface of the stirring tank 1 to the lower end of the blade.
= 0.55, b1 = 23 mm, three paddle blades 3 having a sweep angle of about 30 ° and an ascending angle of about 15 °, and one paddle blade 3 above each.
D2 / D = 0.45, b2 = 2 with an interval of 20 mm
Two stages of turbine-shaped blades 4 having 6 mm and I = 32 mm and paddle blades having an inclination angle of about 45 ° downward were arranged. The stirring shaft 2
Is rotated by an inverter motor 11 whose rotation speed can be changed within a range of 0 to 500 rpm, which is installed outside the tank.
Four baffles 5 each having a width of 25 mm were used at intervals of 90 degrees, and the lower end position of the baffle plate 5 was set at the lower end position of the straight body of the stirring tank. In addition, a predetermined amount of air can be blown from the single-hole nozzle 9 that is opened at an arbitrary position and in any direction.

(2) Measuring Apparatus and Method In FIG.
Is provided with a torque meter A to measure the torque.
In addition, a sampling tube B for measuring the bubble content,
Sampling container C, trap container D, digital manome
And a vacuum pump F. Sump of known capacity
The pressure in the ring container C is reduced in advance, and water containing gas is sampled.
And calculate the bubble content in the stirring tank by the following formula.
Was. V_G= (V-V_L) ・ P₂-VP₁  ε_G1= V_G/ (V_G+ V_L) × 100 where the above symbols are as follows. V: Sampling container volume (L) V_G： Entrained gas volume in sampling water (L) V_L： Liquid sampling capacity (L) P₂: Pressure after sampling (atm) P₁: Pressure before sampling (atm) ε_G1: Bubble content (vol%)

A scale G is provided on the outer wall of the stirring tank 10.
Stuck, stop stirring from the scale, and do not vent
Liquid level in the state (L = D), stirring, and ventilation
The average liquid level (La) at the time was read by visual observation.
Was. As a first method for quantifying the superiority / disadvantage of gas dispersibility,
When an equal amount of gas is blown from the nozzle 9 into the stirring tank
In cases where the gas hold-up amount is larger,
It has a long residence time and a short pass
It was determined that the gas dispersion was excellent at a low rate. In addition, gas ho
The field-up amount was calculated by the following equation. V₁= Π / 4 · D³+ 1/2 / π / 12D³= 7π / 2
4 ・ D³  V₂= Π / 4 · D²・ La + 1/2 ・ π / 12D³  ε_G2= (V₂-V₁) / V₂× 100 However, the above symbols are as follows. V₁: Volume of water in stirring tank (L) V₂： Expansion liquid volume including gas (L) ε_G2: Gas hold-up (vol%) Further, a second method for quantifying the superiority of gas dispersibility is
When an equal amount of gas is blown from the nozzle 9 into the stirring tank
In this case, the stirring power (Pg) and the non-aerated stirring power (Pg)
Excellent dispersibility when the ratio of (o) is smaller (Pg / Po)
It has been said. That is, generally when gas is ventilated
Can reduce the liquid density due to the inclusion of gas in the liquid,
Bubbles in the direction of blade rotation seen in turbine blades
Power (stirring power)
There is a phenomenon that the ratio decreases,
It was determined that the gas dispersibility was excellent.

Example 1 The stirring device shown in FIG. 5 was used for stirring at a rotational speed of 350 rpm, a nozzle hole diameter of 12.7 mm, and a gas blowing amount of 13.7 m ³ / h.
The nozzle hole position was about 40 mm from the wall of the stirring tank at the height of the lower turbine blade, and the blowing direction was horizontal to the lower turbine blade direction. The sampling tube B was inserted about 60 degrees in the stirring rotation direction with respect to the gas injection nozzle at a position about 30 mm from the stirring tank wall at the lower end of the straight body of the stirring tank to perform sampling. In this test, the bubble content (ε _G1 ) at the sampling nozzle position was 7.6 vol%, the stirring tank gas hold-up (ε _G2 ) was 7.4 vol%, and the stirring power ratio (Pg /
Po) was 0.63. Table 1 shows the results.

COMPARATIVE EXAMPLE 1-1 Except that the gas blowing direction was vertically downward, the stirring rotation direction, and the stirring rotation reverse direction, the bubble content, the stirring tank gas hold-up, and the stirring power ratio were changed under the same conditions as in Example 1. It was measured. Table 1 shows the results.

Comparative Example 1-2 Except that the tip height of the gas injection nozzle was set to the middle position of the upper / lower turbine blades, and the blowing direction was set to four directions: vertical downward, horizontal stirring axis direction, stirring rotation direction, and stirring rotation reverse direction. Measured the bubble content, the gas hold-up of the stirring tank, and the stirring power ratio under the same conditions as in Example 1. Table 1 shows the results.

Comparative Example 1-3 Except that the tip height of the gas injection nozzle was the upper turbine blade position, and the blowing direction was four directions: vertical downward, upper turbine blade direction, stirring rotation direction, and stirring rotation reverse direction. Under the same conditions as in Example 1, the bubble content, the gas hold-up of the stirring tank, and the stirring power ratio were measured. Table 1 shows the results.

[0045]

[Table 1]

As is clear from the results in Table 1, regarding the gas dispersibility, it can be said that the nozzle position is better in the order of the lower turbine blade height, the upper / lower turbine blade middle, and the upper turbine blade, and the gas is blown out at the same height. Looking at the influence of the direction, at the lower turbine blade height, the vertical direction facing the turbine blades is at the same level and has good dispersibility, and then the stirring rotation reverse direction,
In the upper and lower turbine blade heights, the horizontal stirring axis direction and the stirring rotation reverse direction are at the same level and the dispersibility is good, then the vertical downward direction, the stirring rotation direction, and the upper turbine blade height. As for the results, the results showed that the dispersibility was good in the order of the upper turbine blade direction, the vertical downward direction, the stirring rotation reverse direction, and the stirring rotation direction. Regarding the bubble content in the lower part of the straight body of the stirring tank, the height of the lower turbine blade was highest at the nozzle position, and the result was almost equal between the middle of the upper / lower turbine blade and the position of the upper turbine blade.
Also, looking at the effect of the blowing direction at the same height, at the lower turbine blade height, the vertical downward direction has the highest bubble content, then the turbine blade direction and the reverse direction of the stirring rotation are at the same level, and the stirring rotation direction is the same. At the lowest, upper / lower turbine blade height, and upper turbine blade height, the vertical downward direction also had the highest bubble content, and the others showed no significant difference. Therefore, in order to improve the overall gas dispersibility and to suppress the blown gas from flowing out into the gas phase of the polymerization tank or into the slurry liquid withdrawn from the polymerization tank through a short pass, the lower turbine is positioned at the lower turbine blade position. It can be said that the method of blowing gas in the wing direction is most advantageous.

Example 2 In FIG. 5, the same test as in Example 1 was performed except that a stirring tank 10 having an inner diameter (D) of 600 mm was used.
In this embodiment, the sizes of the stirring blades and the baffle plates, and their setting positions were prepared in a similar manner to that of the first embodiment, and the ratio was the inner diameter ratio of the stirring tank (600 mm / 310 mm).
The measuring device is the same as in Example 1, but as a third method for quantifying the superiority of the gas dispersibility, the liquid level fluctuation height (Lb) is read by visual observation from a scale newly attached to the outer wall of the stirring tank. Was. In other words, when an equal amount of gas is blown into the stirring tank from the nozzle 9, the lower the liquid surface swing height, the smaller the ratio of the blown gas to the upper part of the liquid surface due to a short pass, and the better the dispersibility. I said With the stirring device shown in FIG. 5, the stirring rotation speed is 225 rpm and the nozzle hole diameter is 16.7 m.
m, the gas blowing rate was 22.9 m ³ / h, the nozzle hole position was about 80 mm from the stirring tank wall at the height of the lower turbine blade, and the blowing direction was horizontal to the lower turbine blade direction.
In addition, the sampling tube B was inserted at about 60 degrees in the stirring rotation direction with respect to the gas injection nozzle, at a position about 60 mm from the stirring tank wall, and at the lower level of the straight body of the stirring tank to perform sampling. In this test, the bubble content (εG1) at the position of the sampling nozzle was 4.7 vol% and the gas hold-up of the stirring tank (εG2) by the above-described calculation method.
Is 6.5 vol%, the stirring power ratio (Pg / Po) is 0.7
7. The liquid level fluctuation (Lb-L) was 47 mm. Table 2 shows the results.

Comparative Example 2 The following comparative test was carried out except for the case where the gas was blown in the stirring and rotating direction in which the gas dispersibility was found to be clearly inferior in Comparative Example 1.

Comparative Example 2-1 A bubble content, a stirring tank gas hold-up, a stirring power ratio, and a liquid level fluctuation were performed under the same conditions as in Example 2 except that the gas blowing direction was vertically downward and the stirring rotation was reversed. Was measured.
Table 2 shows the results.

Comparative Example 2-2 Example except that the tip height of the gas injection nozzle was set at the middle position of the upper / lower turbine blades, and the blowing direction was set to three directions: vertical downward, horizontal stirring axis direction, and stirring rotation reverse direction. 2
Under the same conditions as above, bubble content, stirring tank gas hold-up,
The stirring power ratio and liquid level fluctuation were measured. Table 2 shows the results.

Comparative Example 2-3 Same as Example 2 except that the tip height of the gas injection nozzle was the upper turbine blade position, and the blowing direction was vertically downward, the upper turbine blade direction, and the reverse direction of the stirring rotation. Under the conditions, the bubble content, stirring tank gas hold-up, stirring power ratio, and liquid level fluctuation were measured. Table 2 shows the results.

[0052]

[Table 2]

As is evident from the results in Table 2, regarding the gas dispersibility, the nozzle position is the lower turbine blade position,
It can be said that the order of the upper / lower turbine blade middle and the upper turbine blade is better in this order. Regarding the influence of the blowing direction, the turbine blades are generally integrated at any of the lower turbine blade position, the upper / lower turbine blade intermediate position, and the upper turbine blade position. It is determined that the direction (stirring axis) is excellent in gas dispersibility. Further, the superiority in the vertical downward direction and the reverse direction of the agitation rotation varies depending on the nozzle position and the above-described quantification methods 1 to 3 of the gas dispersibility, and it is not possible to judge that either is superior. On the other hand, with respect to the bubble content at the lower part of the stirring tank, the bubble content was lower as the nozzle position was higher. Also, looking at the effect of the blowing direction at the same height, the results show that at any height, the bubble content is higher in the order of vertical downward, turbine blade (stirring shaft) direction, and stirring rotation reverse direction. became. Therefore, in order to improve the overall gas dispersibility and to suppress the blown gas from flowing out into the gas phase of the polymerization tank through a short pass even in combination with the results of Example 1, it is necessary to set the lower turbine blade position at the lower turbine blade position. The method of injecting gas into the turbine blade direction is the most advantageous.In addition, in the gas injection in the vertical downward direction, it is judged that there is a risk that the gas is most likely to flow out by short-passing into the slurry liquid extracted from the polymerization tank. You.

Example 3 The tendency of air bubbles in a stirring tank was clarified, and the bubble distribution rate in the tank was measured in order to clarify the effectiveness of the invention. In this embodiment, the same apparatus as in the first embodiment is used except that the sampling tube B is sequentially moved to the 12 locations shown in FIG. 6, and the gas holding up (ε _G2 ) of the stirring vessel and the bubble content in the 12 locations of the stirring vessel are performed. The rate was measured.

The stirring device shown in FIG.
rpm, nozzle hole diameter 8.5 mm, gas blowing amount 4.1
m3 / h, the nozzle hole position was about 40 mm from the stirring tank wall at the height of the lower turbine blade, and the blowing direction was the horizontal direction of the lower turbine blade. In this test, the gas hold-up (ε _G2 ) of the stirring tank was 6.5 vol% according to the calculation method described above, and the bubble ratio at each point shown in FIG. 6 was from the upper part to the lower part.
0.4, 9.9, 9.5, 11.4, 8.8, 1.5,
The results were 0.0, 2.1, 6.6, 7.7, 4.9, and 4.2.

Comparative Example 3-1 Example 3 except that the gas blowing direction was vertically downward.
Under the same conditions as described above, the gas hold-up (ε _G2 ) of the stirring tank and the bubble content in each of the 12 stirring tanks were measured.

COMPARATIVE EXAMPLE 3-2 Except that the position of the gas blowing nozzle was set between the upper and lower stages of the turbine blade, the same conditions as in Example 3 were used, and a gas hold-up (ε _G2 ) of the stirring tank and bubbles in each of the 12 stirring tanks were performed. The content was measured.

COMPARATIVE EXAMPLE 3-3 Agitated tank gas hold-up (ε _G2 ) and 12 The bubble content in the stirring tank at each location was measured.

The bubble rate (ε) of Example 3 and Comparative Examples 3-1 to 3-3
_G ) The measurement results of the distribution are shown in FIG. In Example 3, it is expected that the gas hold-up of the stirring tank is high and the gas dispersibility is high, but in fact, even if the bubble content distribution in the tank is observed, the dispersion in the circumferential direction is small and the dispersibility is the most excellent. It is clear that there is. In Comparative Examples 3-1 and 3-2, a point having a high air bubble rate was observed near the blowing gas nozzle at the upper portion, and it can be said that there is a tendency for gas to blow through. Comparative Example 3
In the case of -3, it is clear that a region with a much higher bubble rate exists and a blow-through occurs. On the other hand, the distribution of the bubble ratio at the bottom was not much different from that of Example 3 and Comparative Example 3-1. The whole gas dispersibility was good, and the blown gas was short-passed in the gas phase of the stirring tank or in the slurry discharged from the stirring tank. It can be said that the most advantageous method for suppressing the outflow due to blowing gas is to inject the blowing gas in the direction of the lower turbine blade at the position of the lower turbine blade.

[0060]

According to the method of the present invention, in 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-based system. When using a reaction tank having a heat removal facility that removes by evaporating an evaporant such as a solvent (dispersion medium) and returning non-condensable gas in the reflux condenser included in the heat removal facility to the liquid phase of the polymerization tank. By substantially increasing the dispersibility of the gas in the liquid phase, it is possible to suppress the gas from flowing out in the gas phase of the polymerization tank or into the slurry liquid withdrawn from the polymerization tank by short-path, Great value.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of an α-olefin polymerization method according to the present invention.

FIG. 2 is a top view and a side view showing three paddle blades.

FIG. 3 is a top view and a side view showing a four-turbine blade.

4A and 4B are a top view and a side view showing the position of a gas blowing nozzle.

FIG. 5 is a diagram of a model test facility for confirming the effect of the present invention.

FIG. 6 is a diagram of a bubble content measuring portion for grasping a bubble ratio distribution in a stirring tank.

FIG. 7 is a diagram showing a measurement result of a bubble rate distribution in a stirring tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polymerization tank 2 Stirring shaft 3 Paddle blade 3a Paddle blade 4 Turbine blade 4a Disc-shaped support plate 4b Turbine blade 5 Baffle plate 6 Reflux condenser 7 Gas-liquid separation drum 8 Blower 9 Gas blowing nozzle 10 Stirring tank 11 Inverter motor 12 Flow meter 13 Pressure gauge 14 Extraction pump A Torque meter B Sampling tube C Sampling container D Trap tube E Digital manometer F Vacuum pump G Scale P1 to P4 Sampling position L1 to L3 Sampling height

Continued on the front page (72) Inventor Yukimasa Matsuda 3-10, Ushidori, Kurashiki-shi, Okayama Prefecture Mitsubishi Chemical Co., Ltd. Mizushima Office (72) Inventor, Naoki 3-10, 3--10 Utsudori, Kurashiki-shi, Okayama Prefecture Mitsubishi Chemical Corporation Mizushima Plant F-term (reference) 4J011 DA02 DA03 DB13 DB15 DB19 DB27 FA06 FB07 JB12

Claims (2)

[Claims] 1. A polymerization tank equipped with a multi-stage stirring blade,
In the presence of a stereoregular catalyst, α-olefin is subjected to slurry polymerization or bulk polymerization, a polymerization solution is withdrawn using a pump, and the generated polymerization heat is removed using latent heat due to evaporation of an evaporating substance. -In the method for producing an olefin polymer, when a part of the gas evaporated from the upper part of the polymerization tank is liquefied by a reflux condenser, the pressure of the non-condensed gas is increased by a blower, and the gas is returned to a liquid phase portion of the polymerization tank by a single-hole nozzle. The tip position of the nozzle is the same as or higher than the height of the lowest turbine blade, and the ratio (H / D) of the height difference (H) to the inner diameter (D) of the polymerization tank is 0 to 0.3. And the blowing direction has a swing angle (β) of −30 to +30 degrees with respect to the stirring axis direction, and blows downward at an inclination angle (α) of 0 to 60 degrees with respect to the horizontal direction. Of the blades of the lowermost turbine blade Method for producing α- olefin polymer is characterized. 2. The stirring blade comprises a paddle blade and a turbine blade protruding from a stirring shaft, and the paddle blade is disposed at a lower end of the stirring shaft, and has a shape from the stirring shaft to a tip end of the blade. The angle of receding (γ) with respect to the rotation direction of the shaft is increased so that the receding angle at the tip is in the range of 25 to 50 °, and is composed of three paddle blades having a rising angle (δ) of 10 to 20 °. The ratio (d) of the diameter (d1) of the paddle blade to the diameter (D) of the polymerization tank
1 / D) is in the range of 0.5 to 0.75, and the ratio (b1 / d1) of the paddle blade width (b1) to the paddle blade diameter (d1) is 0.1 to 0.2. The turbine blade is provided above the paddle blade, and the size thereof is determined by the ratio (d2) of the diameter (d2) of the turbine blade to the diameter (D) of the stirring tank. / D) is 0.4 to 0.6
In the range, the ratio (b2 / d2) of the width (b2) of the turbine blade to the diameter (d2) of the turbine blade is 0.15 to 0.2.
5, and the ratio (I / d2) of the blade length (I) of the turbine blade to the diameter (d2) of the turbine blade is 0.2.
0.3, and the blades of the turbine blade are 3
The paddle blades are provided in a number of 4 to 6 with an inclination angle (θ) of 0 to 60 °. The distance (C) between the lower end of the blade and the bottom of the stirring tank and the diameter of the stirring tank ( D) ratio (C
The method for producing an α-olefin polymer according to claim 1, wherein the α-olefin polymer is disposed at a position where / D) is 0.2 or less.