JP2002003508A - METHOD FOR PRODUCING alpha-OLEFIN POLYMER - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an α-olefin polymer whereby the outflow of an uncondensed gas to a gas phase of a polymerization tank and to a slurry liquid by short path can be controlled when the gas is backed to a liquid phase of the tank in a slurry polymerization or bulk polymerization of an α-olefin. SOLUTION: The method wherein the polymerization tank equipped with an impeller stirrer is used for the slurry polymerization or bulk polymerization of an 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 a part of gas vaporized from the upper tank is liquefied in a reflux condenser, a spouting direction has a deflection angle (β) of -60 to +60 deg. to the stirring axial direction and the spout is performed at a lower slope angle (α) of 0 to 60 deg. to the horizontal direction when the uncondensed gas is pressurized by a blower and backed to the liquid phase of the tank by a single hole nozzle.

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 for slurry polymerization or bulk polymerization of an olefin polymer, and 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. About.

[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 inside 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), generally, if the residence time of the stereoregular catalyst is reduced, the efficiency of the catalyst (the production amount of the α-olefin polymer per unit catalyst) decreases, which is not desirable.
The method (1) in which the reactor volume is reduced by operating the solid particles in the slurry inside the reactor at a higher concentration is desirable.

In the case of a loop reactor, in order to maintain the operation performance of a slurry circulation pump 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 stirred tank reactor. It is generally lower than. In addition, in the case of a loop type reactor, a heat removal facility for removing the amount of heat generated from the 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 is required. It is. As a heat removal method, a jacket is attached to the outside of a loop reactor or a stirring tank, or a reactor in which a plurality of heat removal coil type obstructions are disposed inside the reaction tank, 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 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 capacity of a heat removal facility is to increase the heat transfer area of a heat exchanger of the heat removal facility. In equipment that removes heat by using heat in a loop type reactor or a reactor equipped with a heat removal coil-type baffle inside the reaction tank, or a jacket installed on the outside of the stirring tank, the reactor itself is used. 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 additionally provided.

When the slurry in the stirring tank is externally circulated by a circulation pump or the like, 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. 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.

A multi-tube heat exchanger attached to a slurry circulation system is generally provided with a 50 mm tube 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 converter in order to increase the heat removal capacity is disadvantageous industrially because the volume of the heat converter 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. Because it is small, a tube with 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 in comparison with the slurry cooler, the heat removal method is most suitable for improving the productivity of the reactor without increasing the volume of the heat exchanger. I can say.

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 industrially suitably used. 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.

On the other hand, as typified by impact copolymer grade polypropylene, in order to improve the quality of the product obtained by the polymerization of α-olefin, the particle size of the solid product particles is conventionally 400 to 400 μm. 600 μm
Recently, catalysts having a large product solid particle diameter of 700 to 1500 μm (sometimes 1500 to 2000 μm are found in some cases) are frequently used. When the product particle diameter is increased, it is necessary to increase the stirring rotation speed for uniform mixing and suspension of the particles in the polymerization tank, the stirring load becomes excessive, and the proportion of gas in the liquid phase increases, and Foaming at the slurry interface (Foam
ing) phenomenon occurs, and the performance of the reflux condenser for liquefying the evaporant may be significantly reduced due to the scattering of the polymer, which makes it difficult to employ the above-described multi-stage turbine type stirring blade. Is also possible.

A method for producing an α-olefin polymer in the case where a product having a large particle diameter of 500 to 2000 μm is required, is disclosed in Japanese Patent Application No. 20-209, filed by the present inventors.
No. 00-183868, it prevents sedimentation and separation of solid particles in the polymerization tank, improves the uniform mixing performance of the slurry, and evaporates the α-olefin or hydrocarbon solvent (dispersion medium). Bottom paddles and arm paddles that reduce the content of gas generated in the slurry, substantially increase the amount of solid particles retained in the reactor, improve catalyst efficiency, and reduce the power required for stirring. , And a stirring blade composed of a lattice blade composed of strips are preferably used.

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 non-condensable gas such as hydrogen in the polymerization tank.

[0013] Of the non-condensable gases, those which are returned to the polymerization tank, it is desirable to return all or part of the non-condensable gas to the liquid phase in order to maintain gas-liquid equilibrium in the polymerization tank. If this is inappropriate, it may cause a process problem. That is, when the gas is returned to a position where the gas cannot be sufficiently dispersed or turned to the direction, the residence time of the gas in the liquid phase portion is short, so that the gas generated by the evaporation of the evaporant due to the heat of reaction is sufficiently reduced. And the gas-liquid equilibrium in the polymerization tank is impaired. In addition, when the rise of the gas is localized near the interface, the liquid surface oscillates, and the number of droplets increases, and when the polymer accompanies the droplets and reaches the condenser, the heat transfer surface of the condenser is reduced. There arises a problem that the dirt coefficient increases and its performance is reduced. 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 to improve gas dispersibility. However, installation of equipment with a complicated shape in the polymerization tank may cause the formation of lumps. In addition, 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 single-hole nozzle having a simpler structure and a small pressure loss.

When the gas is returned to the vicinity of the bottom of the polymerization tank, the gas dispersibility tends to improve due to an increase in the residence time of the gas. However, generally, the slurry is withdrawn from the reactor. This is often performed from the lower part of the straight body of the reactor or from the bottom of the reactor, and since the return position of the gas approaches the slurry extraction position of the polymerization tank, the extracted slurry contains a large amount of light-boiling components. May be mixed. In such a case, if the slurry is extracted from the polymerization tank by a pump, a slight pressure drop may occur.
Alternatively, air bubbles are generated in the slurry liquid due to an increase in temperature, and cavitation occurs in the pump, thereby impairing stable production.

[0015]

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.

[0016]

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, by specifying the position of the nozzle and the blowing direction when returning the non-condensable gas, The inventors have found that a good α-olefin polymer can be obtained by stirring the inside of the polymerization tank using a specific stirring blade, and completed the present invention.

That is, according to the present invention, in a polymerization tank equipped with a stirring blade, α-olefin is subjected to slurry polymerization or bulk polymerization in the presence of a stereoregular catalyst, and a polymerization solution is withdrawn using a pump. In the method for producing an α-olefin polymer, in which the generated heat of polymerization is removed by utilizing the latent heat generated by the evaporation of the evaporating substance, a part of the gas evaporated from the upper part of the polymerization tank is liquefied by a reflux condenser and is not condensed When the gas is pressurized with a blower and returned to the liquid phase portion of the polymerization tank with at least one single-hole nozzle, the blowing direction is -60 with respect to the stirring axis direction.
A method for producing an α-olefin polymer, which has a swing angle (β) of up to +60 degrees and blows out at a downward inclination angle (α) of 0 to 60 degrees with respect to the horizontal direction.

Further, according to the present invention, the structure of the polymerization tank used for the polymerization of α-olefin and the stirring tank is such that a stirring shaft rotatable by a driving source from outside the tank is provided at the center of the vertical cylindrical polymerization tank. The ratio (C / D) of the distance (C) from the bottom wall of the polymerization tank to the lower end of the stirring blade and the diameter (D) of the polymerization tank is provided on the stirring shaft.
, A stirring blade comprising a large bottom paddle blade disposed at a position where is not more than 0.1, an arm paddle above the bottom paddle blade, and a lattice blade composed of a strip extending in a direction perpendicular to the arm paddle. This is a method for producing the above-mentioned α-olefin polymer using a polymerization tank equipped with.

Further, the present invention provides the above-described stirring blade structure, wherein the stirring blade structure uses a polymerization tank equipped with a stirring blade composed of a lattice blade having a diameter of an upper arm paddle blade shorter than that of a bottom paddle blade. It is a manufacturing method of the alpha-olefin polymer of said description.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a polymerization tank equipped with a stirring blade composed of a lattice blade composed of a bottom paddle, an arm paddle, and a strip, in the presence of a stereoregular catalyst and an α-olefin. Is subjected to slurry polymerization or bulk polymerization. In the present invention, the α-olefin used as a raw material has 2 to 18 carbon atoms, particularly 2 to 8 carbon atoms, for example, ethylene, propylene, 1-butene, 1-
Penten, 1-hexene, 1-octene and the like can be mentioned. 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, and 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
6, JP-A-1-54007 and JP-A-3-7250
No. 3).

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 and magnesium fluoride; alkoxy magnesium such as methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, hexoxy magnesium chloride and octoxy magnesium chloride Allyloxymagnesium such as phenoxymagnesium chloride and methylphenoxymagnesium chloride halide; alkoxymagnesium such as methoxymagnesium, n-octoxymagnesium and 2-ethylhexoxymagnesium; allyloxy such as phenoxymagnesium and methylphenoxymagnesium Magnesium; such as magnesium laurate and magnesium stearate It can be obtained from such carboxylates Neshiumu. 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
l₃, Ti (OC₂H₅) Cl₃, Ti (On-C₄H₉)
C1₃, Ti (Oi-C₄H₉) C1₃, Ti (OCH
₃) Br₃, Ti (OC₂H₅) Br₃, Ti (On-
C₄H₉) Br₃, Ti (Oi-C₄H₉) Br₃Such as
Trihalogenated alkoxytitanium; Ti (OCH₃)₂
Cl₂, Ti (OC₂H₅)₂Cl₂, Ti (On-C
₄H₉)₂Cl₂, Ti (Oi-C₄H₉)₂Cl₂, T
i (OCH₃)₂Br₂, Ti (OC₂H₅)₂Br₂,
Ti (On-C ₄H₉)₂Br₂, Ti (Oi-C₄H
₉)₂Br₂Dihalogenated alkoxytitanium such as T;
i (OCH₃)₃Cl, Ti (OC₂H₅)₃Cl, T
i (On-C₄H₉)₃Cl, Ti (Oi-C₄H₉)
₃Cl, Ti (OCH₃)₃Br, Ti (OC₂H₅)
₃Br, Ti (On-C₄H₉)₃Br, Ti (Oi-
C ₄H₉)₃Monohalogenated alkoxy titers such as Br
; Ti (OCH₃)₄, Ti (OC₂H₅)₄, Ti
(On-C₄H₉)₄, Ti (Oi-C₄H₉)₄Such
Or a mixture thereof;
Alternatively, an aluminum compound and a silicon compound
Substances, sulfur compounds, other metal compounds, hydrogen halides,
Halogen is mixed with the above general compounds
Formula Ti (OR) _gX_4-g(R is a hydrocarbon group, X is halo
And g is a number satisfying 0 ≦ g ≦ 4).
By titanium compound, hydrogen halide, halogen etc.
It is common to introduce.

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, 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.

In the present invention, as the electron-donating compound in the solid catalyst component used as necessary, a compound which is generally used in this type of stereoregular catalyst can be used. Generally, oxygen-containing compounds and / or nitrogen-containing compounds can be mentioned as preferred.

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

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 nisate, methyl methoxybenzoate, methoxybenzoate
Ethyl fragrance, methyl methacrylate, ethyl methacrylate
Dimethyl phthalate, diethyl phthalate, diphthalate
Propyl, dibutyl phthalate, diisobutyl phthalate,
Dihexyl phthalate, γ-butyrolactone, ethylcello
Solvents and the like, as (d) alkoxysilanes,
Alkoxy groups (including aryloxy groups;
About 1-18, preferably about 1-4)
Possess at least one and the remaining valence of the silicon atom is
A kill group, an aryl group or an aralkyl group (these general
Is the same as that described above), Tet
Lamethoxysilane, ethyltrimethoxysilane, n-p
Ropirtrimethoxysilane, isopropyltrimethoxy
Silane, t-butyltrimethoxysilane, phenyltri
Methoxysilane, cyclohexyltrimethoxysilane,
1-methylcyclohexyltrimethoxysilane, 1,
1,2,2-tetramethylpropyltrimethoxysila
, Diethyldimethoxysilane, di-n-propyldimene
Toxicsilane, diisopropyldimethoxysilane, diph
Enyldimethoxysilane, t-butylmethyldimethoxy
Silane, t-butylethyldimethoxysilane, t-butyl
Le-n-propyldimethoxysilane, t-butyl isop
Ropirdimethoxysilane, cyclohexylmethyldimet
Xysilane, dicyclohexyldimethoxysilane, 1-
Methylcyclohexylmethyldimethoxysilane, 1,
1,2,2-tetramethylpropylmethyldimethoxy
Orchid, ethyltriethoxysilane, n-propyltrie
Toxysilane, isopropyltriethoxysilane, t-
Butyltriethoxysilane, phenyltriethoxysila
, Cyclohexyltriethoxysilane, 1-methylsilane
Clohexyltriethoxysilane, 1,1,2,2-te
Tramethylpropyltriethoxysilane, diethyldie
Toxisilane, di-n-propyldiethoxysilane, di
Isopropyldiethoxysilane, diphenyldiethoxy
Silane, t-butylmethyldiethoxysilane, t-butyl
Ruethyldiethoxysilane, t-butyl-n-propyl
Diethoxysilane, cyclohexylmethyldiethoxy
Orchid, cyclohexylethyldiethoxysilane, 1-meth
Tylcyclohexylmethyldiethoxysilane, 1,1,
2,2-tetramethylpropylmethyldiethoxysilane
And the like.

Of these compounds, those preferably used are piperidines or alkoxysilanes, particularly preferably alkoxysilanes. 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. Further, 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 polymerization tank provided with a stirring blade composed of a lattice wing composed of a bottom paddle, an arm paddle and a strip. For example, using the apparatus shown in FIG. Can be done. Figure 1
In the above, the polymerization vessel 1 has a stirring blade 3 on a stirring shaft 2, and in the presence of a stereoregular catalyst, slurry polymerization or bulk polymerization of α-olefin is performed, and α-olefin evaporated from the upper portion by reaction heat The other feed is first introduced into the condenser 6, which liquefies a gas which is easily condensed in the vessel, and is separated into gas and liquid by the next drum 7. The non-condensed gas is pressurized by the blower 8 and returned to the polymerization tank 1. Then, a heat removal system is used in which the condensed liquid is pressurized by a self-pressure or a pump 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.

In FIG. 1, a stirring shaft 2 rotatable by a driving source 4 from the outside of the tank is provided at the center of a vertical cylindrical polymerization tank 1. The ratio (C / D) of the distance (C) to the part (C) and the diameter (D) of the polymerization tank is 0.
As shown in FIG. 2, a large bottom paddle blade 11 is disposed at a position not more than 1 and an arm paddle 13 and a strip 12 extending in a direction perpendicular to the arm paddle above the bottom paddle blade. As shown in FIG. 3, the agitating blade 3 composed of a lattice blade or a structure of the agitating blade, as shown in FIG.
A stirring blade 3 having a smaller diameter is used. Specifically, JP-A-61-200842, JP-A-6-200842 and
No. 312122, JP-A-8-252444,
Max blend blades manufactured by Sumitomo Heavy Industries, Ltd. described in JP-A-8-252445 are preferred.
The shape of the stirring blade is such that the diameter (d1) and the height (h) are d1 / D = 0.45 to 0.5 with respect to the inner diameter (D) of the polymerization tank 1.
7, h / D = 0.6 to 1.2 is preferable, and d1 / D is more preferable.
= 0.5-0.6, h / D = 0.7-1.1, such that the diameter of the upper arm paddle blade 13 is shorter than the diameter of the bottom paddle blade 11 as shown in FIG. In this case, the intersection angle (β) between the arm paddle blade 13 and the strip 12 is 80 to 90 degrees, more preferably 85 to 90 degrees. Furthermore, from the lower part to the upper part on the straight body wall of the polymerization tank 1,
Four to twelve baffle plates 5 are arranged along the side wall surface at intervals in the circumferential direction.

The blowing direction of the gas blowing nozzle 9 is
As shown in FIG. 4, the air blows at a swing angle (β) of −60 to +60 degrees with respect to the stirring axis direction and blows at a downward inclination angle (α) of 0 to 60 degrees with respect to the horizontal direction. The position of the contact point between the above-mentioned extension line in the blowing direction and the orbit of the stirring 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 present invention is not limited to this. The nozzle may be introduced into the polymerization tank from the straight body portion, and the number of blowout nozzle holes is not limited to one, and may be divided into a plurality. Further, in FIG. 4, there is no particular limitation on the distance (X) when the blade and the tip of the nozzle are closest to each other due to the rotation of the stirring blade, but the ratio (X /
It is desirable that d1) be in the range of 0.05 to 0.2. Although there is no particular limitation on the nozzle hole diameter, when the blower is operated at the maximum throughput, the nozzle linear velocity is 100 m / s.
ec or less.

According to the method of the present invention, the gas blown out from the single-hole nozzle first collides with the stirring blade, and is divided into bubbles having a smaller diameter. The buoyancy of the reduced gas decreases, and due to the synergistic effect with the stirring effect of the stirring blade, the gas is dispersed throughout the polymerization tank without short-passing to reach the upper liquid surface in a short time. Further, by reducing the bubble diameter and increasing 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 agitating shaft direction described in the present invention, it is roughly classified into a vertically downward direction, a vertically upward direction, a horizontal and rotational rotation direction, and a horizontal and reverse rotational direction. 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. When the gas is blown vertically upward, in the stirring rotation direction, or in the direction opposite to the stirring rotation, the gas is not injected into the tank due to the fact that the bubble diameter is not reduced by the stirring blade immediately after the blowing. The dispersion of the gas is inferior to the case according to the method of the present invention, and rises without being sufficiently mixed with the gas generated by evaporation of the evaporant due to the heat of reaction in the liquid phase portion of the polymerization tank and rises to the gas phase portion. Will arrive. In such a state, since the gas is cooled and condensed by the condenser and has a lower temperature than the reactor liquid temperature, and the gas containing a large amount of light-boiling components reaches the gaseous phase portion through a short pass, The gas-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 enters the condenser. 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.

When the gas is blown vertically downward and near the bottom of the tank, even if the bubble diameter is not sufficiently reduced by the stirring blade immediately after blowing, the gas phase The gas dispersibility tends to improve due to an increase in the residence time in the medium, but if the blowing speed is high,
Generally, withdrawal of the slurry from the reactor is often performed from the lower part of the straight body of the reactor or 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 pumping out the slurry from the polymerization tank or when a pump is present downstream of the process,
A slight pressure drop or temperature increase causes bubbles in the slurry liquid, causing cavitation of the pump and impairing stable production. Equipment is required.

[0038]

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 14 shown in FIG. 5 has an inner diameter (D) of 600 m.
m, height 1,000mm, CMC inside at room temperature
Water adjusted to 10 cp from the lower end of the straight body of the stirring tank
/D=1.0. The stirring shaft 2 is disposed at the center position of the stirring tank 14, and the distance between the bottom wall surface of the stirring tank 14 and the lower end of the blade is 30 mm at the center of the stirring shaft 2. = 320mm, d
2 = 268 mm, d3 = 188 mm, d4 = 148 m
m, b1 = 204 mm, b2 = 338 mm, b3 = 26
A stirring blade of mm, h = 568 mm was provided. The stirring shaft 2
Is rotated by a drive source 4 whose rotation speed can be changed within a range of 0 to 500 rpm, which is installed above the outside of the tank. The four baffles 5 having a width of 48 mm were used at 90 ° intervals, and the lower end of the baffle 5 was set at the lower end 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 device and method In order to measure the power required for stirring, a portion outside the tank of the stirring shaft 2 is used.
A torque meter A is provided. Also the bubble content
Tube B, sampling vessel to measure
C, trap container D, digital manometer E, vacuum port
And a pump F. Reserve a sampling container C of known capacity.
The pressure is reduced and the water containing gas is sampled.
The bubble content in the stirring tank was calculated by the formula. V_G= (V-V_L) ・ P₂-VP₁  ε_G1= V_G/ (V_G+ V_L) × 100 where the symbols used in the above equation 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 stuck on the outer wall of the stirring tank 14.
And stop stirring from the scale, and
Liquid level (L = D), average liquid during stirring and aeration
Visual observation of surface height (La) and liquid surface swing height (Lb)
Read by. First to quantify the superiority of gas dispersibility
As a method, an equal amount of gas is blown from the nozzle 9 into the stirring tank.
The gas hold-up
Gas spreads throughout the tank, and the residence time is long and
The short path ratio was low and the gas dispersion was excellent. What
The gas hold-up amount is calculated by the following equation.
Was. 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 symbols used in the above equation are as follows. V₁: Volume of water in stirring tank (L) V₂： Expansion liquid volume including gas (L) ε_G2: Gas hold-up (vol%)

As a second method for quantifying the superiority of gas dispersibility, when an equal amount of gas is blown into the stirring tank from the nozzle 9, the stirring power (Pg) and the non-aerated stirring power (Po) are used. In which the ratio (Pg / Po) is smaller has excellent dispersibility. That is, there is generally a phenomenon in which the power is reduced, and the smaller the ratio, the better the gas dispersibility. As a third method for quantifying the superiority of the gas dispersibility, the smaller the liquid surface fluctuation (Lb-La), 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. And

Example 1 The stirring device shown in FIG. 5 was used with a stirring rotation speed of 145 rpm, a nozzle diameter of 16.7 mm, a gas blowing amount of 23.7 m ³ / h, a blowing direction of a horizontal stirring shaft direction, and At a position of about 80 mm, the height was moved to 120 mm, 240 mm, and 360 mm in order from the lower end of the straight body of the stirring tank, and gas was blown. Further, sampling was performed by inserting the sampling tube B at about 60 degrees in the stirring rotation direction with respect to the gas blowing nozzle, at a position about 60 mm from the stirring tank wall, and at the lower end of the straight body of the stirring tank. In this test, the bubble content (ε _G1 ) at each sampling nozzle position for each blowing height was 12.8 vol%,
9.1 vol%, 8.6 vol%, gas hold-up (ε _G2 ) of the stirring tank were 7.9 vol%, 6.5 vol, respectively.
%, 6.3 vol%, stirring power ratio (Pg / Po) is 0.84, liquid level fluctuation (Lb-La) is 38 mm,
The results were 71 mm and 62 mm.

From the above results, in order to improve the gas dispersibility, the tip of the nozzle is located in the range from the lower end position of the strip portion of the lattice type stirring blade to one third of the length (b2) of the strip portion. It can be said that it is desirable to provide the air bubbles, but on the other hand, since the bubble content at the lower end of the straight body of the stirring tank increases, α
In the case of olefin polymerization equipment, when there is a limitation in the process such as when the slurry is extracted from the polymerization tank by a pump, the tip of the blowing nozzle is moved from the lower end position of the strip portion of the lattice type stirring blade to the length of the strip portion (b2 )
It is desirable to dispose it above the range of 1/3 to 1/2.

Comparative Column 1 The bubble content, the stirring tank gas hold-up, and the
The stirring power ratio and liquid level fluctuation were measured. According to the calculation method described above, the bubble content (ε _G1 ) at the lower end of the straight body of the stirring tank for each blowing height is 12.5 vol% and 9.3 vol, respectively.
% And 10.4 vol%, which were almost the same as those in the example, the gas hold-up (ε _G2 ) of the stirring tank was 7.3 vol%, 5.3 vol%, and 5.1 vol%, respectively. And the stirring power ratio (Pg / Po)
Rise to 0.90 in all cases, and the liquid level swings (Lb-La)
Respectively increased to 82 mm, 118 mm, and 130 mm, and the gas dispersibility was inferior to the examples in any of the quantification methods.

Comparative Example 2 The bubble content, the gas hold-up of the stirring tank, the stirring power ratio, and the liquid level fluctuation were measured under the same conditions as in the example, except that the gas blowing direction was the reverse of the stirring rotation. According to the calculation method described above, the bubble content (ε _G1 ) at the lower end of the straight body of the stirring tank for each blowing height is 11.6 vol% and 9.4 v, respectively.
ol%, 8.9 vol%, and gas hold-up (ε _G2 ) of the stirring tank were 7.7 vol%, 6.7 vol%, respectively.
5.7 vol%, which is almost the same as that of the embodiment, but the stirring power ratios (Pg / Po) are 0.84, 0.90, 0.9, respectively.
0, the liquid level fluctuation (Lb-La) is 75 mm,
It increased to 98 mm and 113 mm, and the result was that the gas dispersibility was generally inferior to the examples.

[0047]

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 prevent the gas from being short-passed and stopped in the gas phase of the polymerization tank or into the slurry liquid withdrawn from the polymerization tank. Great value.

[Brief description of the drawings]

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

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

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

4A and 4B are a top view and a side view showing a gas blowing nozzle direction used in the present invention.

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

[Explanation of symbols]

 Reference Signs List 1 polymerization tank 2 stirring shaft 3 stirring blade 4 drive source 5 baffle plate 6 reflux condenser 7 gas-liquid separation drum 8 blower 9 gas blowing nozzle 10 boss 11 bottom paddle 12 strip 13 arm paddle 14 stirring tank 15 flow meter 16 pressure gauge 17 Extraction pump A Torque meter B Sampling tube C Sampling container D Trap container E Digital manometer F Vacuum pump G Scale

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukimasa Matsuda 3-10, Ushidori, Kurashiki-shi, Okayama Prefecture Mitsubishi Chemical Corporation Mizushima Office (72) Inventor, Naoki Tohi 3-10-10, Shiodori, Kurashiki-shi, Okayama Mitsubishi Chemical F-term in Mizushima Plant (reference) 4J011 AA01 DB16 DB23 DB32 4J028 AA01A AB01A AC06A AC07A AC08A BA00A BA01B BB00A BB01B BC15B BC17B BC24B BC25B CA15A CA16A CB35A CB56A EB03 EC01 FA01 FA02

Claims (3)

[Claims] 1. An α-olefin is subjected to slurry polymerization or bulk polymerization in the presence of a stereoregular catalyst using a polymerization tank equipped with a stirring blade, and a polymerization solution is withdrawn using a pump. In a method for producing an α-olefin polymer in which heat is removed using latent heat due to evaporation of an evaporating substance, a part of a gas evaporated from an upper part of a polymerization tank is liquefied by a reflux condenser, and a non-condensed gas is blown by a blower. When the pressure is increased and returned to the liquid phase portion of the polymerization tank by at least one single-hole nozzle, the blowing direction has a swing angle (β) of −60 to +60 degrees with respect to the stirring axis direction, and 0 to 0 with respect to the horizontal direction. A method for producing an α-olefin polymer, comprising blowing out at a downward inclination angle (α) of 60 degrees. 2. As a structure of a polymerization tank used for polymerization of α-olefin and a stirring tank, a stirring shaft rotatable by a driving source from outside of the tank is provided at the center of the vertical cylindrical polymerization tank. A large-sized filter is provided on the stirring shaft at a position where the ratio (C / D) of the distance (C) from the bottom wall of the polymerization tank to the lower end of the stirring blade and the diameter (D) of the polymerization tank is 0.1 or less. 2. A polymerization tank comprising a bottom paddle blade and an upper portion of the bottom paddle blade, on which an arm paddle and a stirring blade comprising a lattice blade composed of a strip extending in a direction perpendicular to the arm paddle are mounted.
3. The method for producing an α-olefin polymer according to item 1. 3. The stirring tank structure according to claim 2, wherein the stirring tank structure is provided with a stirring tank comprising a grid blade having a diameter of an upper arm paddle blade shorter than that of a bottom paddle blade. 3. The method for producing an α-olefin polymer according to item 1.