JPH0762009A - Vapor phase polymerization of olefin - Google Patents

Abstract

PURPOSE:To prevent instability due to local polymerization heat, formation of mass and attachment of static electricity to the product by cooling a wall temperature of a reactor to a temperature lower than the dew point of fluid gas when olefin is subjected to continuous vapor phase polymerization in a fluid bed reactor. CONSTITUTION:In a method for subjecting an olefin to continuous vapor phase polymerization in a fluid bed reactor, the polymerization is carried out while cooling wall temperature of a reactor to a temperature lower than the dew point of fluid gas, preferably a temperature 5 deg.C lower than the dew point of the fluid gas. A cooling apparatus is attached to the reactor by the height which is one or two times longer than diameter of the reactor from the bottom of the reactor.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for vapor phase polymerization of olefins in a fluidized bed reactor.

[0002]

2. Description of the Prior Art Olefin polymers have hitherto been produced by solution, bulk, slurry or gas phase polymerization methods. In recent years, the activity of the catalyst has been remarkably improved, and a process which does not require a step of separating a catalyst residue from a produced polymer has been widely used. In particular, a method of vapor phase polymerization of an olefin in a fluidized bed reactor has industrial value. It is highly paid attention.

When producing polymers in a fluidized bed reactor,
Since it is difficult to remove the heat of polymerization, the temperature inside the fluidized bed tends to become unstable due to the local accumulation of heat of polymerization, it is difficult to maintain the fluidized state due to the formation of lumpy polymer, and the polymerization due to the collision of polymer particles, etc. There are problems such that electrostatic adhesion of the produced polymer is likely to occur on the inner wall of the reactor, or that lumps are likely to be produced in the calming compartment where the gas velocity in the upper part of the fluidized bed reactor is reduced.

Japanese Unexamined Patent Publication (Kokai) No. 54-139983 discloses a method for removing heat of polymerization by providing an internal cooler in a fluidized bed reactor. However, regarding the above-mentioned problem of electrostatic adhesion, There is no description.

JP-A-56-4608 discloses that an inert hydrocarbon compound having a carbon number of 3 or more is allowed to coexist in a liquid state in a polymerization reactor, so that a polymer for a polymerization reactor wall or other parts of the reactor is polymerized. It is disclosed to prevent electrostatic sticking of particles. Further, JP-A-58-201802 discloses a method of cooling an unreacted olefin circulation gas to form a two-phase mixture of a gas and an entrained liquid, and reintroducing the mixture into a fluidized bed reactor. . However, in the above method, since the liquid substance is present in the polymerization reactor, there is a problem that the measurement of the differential pressure gauge necessary for controlling the reaction is disturbed and the control of the polymerization reaction tends to be difficult.

[0006]

OBJECT OF THE INVENTION The present invention provides a method for improving the problems of the conventional fluidized bed gas phase polymerization process and enabling a long-term stable polymerization reaction.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a method of continuously vapor-phase polymerizing olefins in a fluidized bed reactor, characterized in that the temperature of the inner wall of the reactor is cooled to below the dew point of the fluidized gas during the polymerization. Regarding the polymerization method.

The olefin polymerization of the present invention is carried out continuously in the gas phase in a fluidized bed reactor. That is, a catalyst component, an olefin monomer, an inert gas, an additive, etc. are continuously introduced into a fluidized bed reactor, and polymerization is carried out while fluidizing catalyst particles and polymer particles by a gas phase component. In continuous polymerization, the produced polymer is continuously or intermittently withdrawn from the reactor, and unreacted monomer gas is continuously discharged from the fluidized bed reactor. The unreacted monomer gas is preferably after removing the entrained fine powder polymer with a cyclone or the like, and then appropriately supplemented with an olefin monomer or the like via a heat exchanger and a compressor through a circulation line, and then from the bottom of the fluidized bed reactor. Will be reintroduced. Examples of the reactor used in the present invention include JP-A-58-201802, JP-A-59-126406, JP-A-2-233708, and JP-A-2-233708.
The fluidized bed reactor described in, for example, 4-234409 can be used.

In the present invention, in the method of continuously vapor-phase polymerizing an olefin in a fluidized bed reactor, the temperature of the inner wall of the fluidized bed reactor during the polymerization is set to be equal to or lower than the dew point of the fluidized gas, preferably 10 ° C., more preferably 5 Cool down about ℃. As the cooling method of the present invention, a method in which a cooling device such as an air cooling fin or a water cooling jacket is attached to the outer wall of the reactor can be used. In the gas-phase fluidized bed polymerization, since the attachment site of the polymer varies depending on the shape of the reactor, the method of injecting the catalyst used, the particle size and shape of the prepolymer, etc., there is no particular limitation on the attachment position of the cooling device. It can be attached to a part of the reactor such as a cylinder part of the reactor or a tranquilizing compartment part in the upper part of the reactor. Under normal polymerization conditions, the reactor diameter should be between 1 and
It is preferable that a cooling device is attached to the height of about twice to carry out the polymerization.

In the present invention, a Ziegler type catalyst composed of a transition metal catalyst solid component and an organoaluminum compound is preferably used as the polymerization catalyst. As the transition metal catalyst solid component, titanium, vanadium, chromium, transition metal compounds of Group IV to VI of the periodic table such as zirconium can be used, and these compounds, for example, magnesium compounds such as magnesium chloride, Alternatively, a highly active catalyst supported on a carrier such as an inorganic oxide such as silicon dioxide, alumina or zirconia is preferably used.

As a method for producing these catalyst solid components, there are disclosed in JP-A-59-8706, JP-A-59-22907 and JP-A-59-2.
2908 publication, 59-64611 publication, 59-71309 publication,
60-42404 JP, 60-133011 JP, 60-215006 JP, 62-232405 JP, 62-297304 JP, JP 1-256502 JP, JP 1-289809 JP, JP-A-3-81
JP 303-88808 JP, JP 3-93803 JP, JP 56-18132 JP, JP 56-15807 JP,
Japanese Patent Publication No. 61-50964, Japanese Patent Publication No. 61-363, Japanese Patent Publication No. 62
The method proposed in -56885 publication can be adopted.
As a typical production method, a method of treating a magnesium chloride carrier obtained by reacting a specific organomagnesium compound, a chlorinated organic compound and an electron addition donor under specific conditions with titanium tetrachloride, and the like can be mentioned.

For example, a granular solid is formed by reacting a Grignard compound solution with a halogenated hydrocarbon compound. More preferably, a spherical solid carrier as a carrier is obtained by adding a chlorinated hydrocarbon compound to a solution of a Grignard compound containing 20% by volume or more of an ether having a total carbon number of 6 or more and reacting at 60 ° C. or less.

Alkyl magnesium chloride is preferably used as the Grignard compound, and specific examples thereof include methyl magnesium chloride, ethyl magnesium chloride, n-butyl magnesium chloride,
Examples include n-hexyl magnesium chloride.

A hydrocarbon solvent such as hexane, heptane, octane, toluene, xylene and cyclohexane may be mixed with the ether in the solution of the Grignard compound.

The halogenated hydrocarbon compound to be reacted with the Grignard compound solution is particularly preferably chlorine.
Mention may be made of saturated or unsaturated hydrocarbon compounds containing carbon bonds. Specific examples thereof include chloroform, methylene chloride, methyl chloride, ethyl chloride, propyl chloride, isopropyl chloride, butyl chloride, sec-butyl chloride, tert-butyl chloride, hexyl chloride, chlorobenzene, dichlorobenzene, trichlorobenzene, and benzyl chloride. Can be mentioned. In addition to the above compounds, an ether compound containing a halogen / carbon bond can also be used, and specific examples thereof include bis-2-chloroethyl ether and 2-chloroethyl methyl ether.

The method of reacting the Grignard compound solution with the halogenated hydrocarbon compound is not particularly limited, and a method of adding the halogenated hydrocarbon compound to a container charged with the Grignard compound solution can be used. .

During the reaction between the Grignard compound solution and the halogenated hydrocarbon compound, unless the Grignard compound is contacted with the Grignard compound to precipitate a solid at room temperature, the Grignard compound solution does not contain any halogen / metal bond in advance. Can coexist.

After contacting the obtained support with an electron donor, a transition metal compound can be subsequently contact-treated to obtain a catalyst solid component.

As the electron donor, organic acid ester, inorganic acid ester, acid halide, ether, acid amide, N, N-
Dialkyl acid amides, amines, nitriles, acid anhydrides, silicate compounds, ketones, alcohols, aldehydes, carboxylic acids, isocyanates and the like can be used.
A silicate compound is particularly preferable.

Examples of the transition metal compound include halides, hydrocarbyl oxyhalides, hydrocarbyloxyhalides, hydrocarbyloxyhydrocarbyl compounds and hydrocarbyls of transition metals of Group IV to VI of the periodic table such as titanium, vanadium, chromium, zirconium and hafnium. Examples thereof include halides, hydrocarbyloxyhydrocarbyl halides, and the like.

A titanium compound can be preferably used as the transition metal compound. Specific examples thereof include methoxytrichlorotitanium, dimethoxydichlorotitanium, trimethoxychlorotitanium, ethoxytrichlorotitanium,
Diethoxydichlorotitanium, propoxytrichlorotitanium, dipropoxydichlorotitanium, butoxytrichlorotitanium, dibutoxydichlorotitanium, phenoxytrichlorotitanium, diphenoxydichlorotitanium, methoxytribromotitanium, phenoxytribromotitanium, methoxytriiodotitanium. , Phenoxytriiodotitanium, tetrachlorotitanium, tetrabromotitanium, tetraiodotitanium, tetramethoxytitanium, tetraethoxytitanium, tetrapropoxytitanium and the like. Two or more kinds of these titanium compounds may be used in combination. Among them, tetrachlortitanium, methoxytrichlortitanium,
Dimethoxydichlorotitanium, ethoxytrichlorotitanium, diethoxydichlorotitanium, propoxytrichlorotitanium, dipropoxydichlorotitanium, butoxytrichlorotitanium and dibutoxydichlorotitanium are particularly preferably used.

Examples of the organoaluminum compound used together with the catalyst solid component include trialkylaluminum, dialkylaluminum halide, dialkylaluminum hydride and alkylalumoxane. Specific examples thereof include trimethyl aluminum, triethyl aluminum, tributyl aluminum, triisobutyl aluminum, trihexyl aluminum,
Examples include trioctylaluminum, diethylaluminum chloride, diethylaluminum hydride, isoprenylaluminum, and methylalumoxane.

In some cases, various electron donating properties may be added as a third component to the above polymerization catalyst system. As the electron donor, organic acid ester, inorganic acid ester,
Acid halides, ethers, acid amides, N, N-dialkyl acid amides, amines, nitriles, acid anhydrides, silicate compounds, ketones, alcohols, aldehydes, carboxylic acids, isocyanates and the like can be used. A silicate compound is particularly preferable.

As the olefin for polymerization, ethylene, propylene, butene-1, pentene-1, 4-methylpentene-
1, linear α-olefins such as 1, hexene-1 and octene-1, and cyclic α-olefins such as cyclopentene and cyclohexene. These α-olefins may be used alone or may be polymerized, or may be copolymerized with a mixture of two or more kinds. Further, a non-conjugated linear chain such as 1,5-hexadiene or a cyclic unsaturated compound such as dicyclopentadiene, 5-ethylidene-2-norbornene and vinylcyclohexene can be copolymerized.

The process according to the invention is particularly suitable for homopolymerization of ethylene or propylene, ethylene or propylene and other α
-It can be suitably used for copolymerization with an olefin.

The fluidizing gas may contain hydrogen and an inert gas. As the inert gas, nitrogen or methane, ethane, propane, butane, normal butane, isobutane, pentane, normal pentane, isopentane,
Examples include saturated aliphatic hydrocarbons such as hexane, octane, and decane.

The dew point of the fluidizing gas is the temperature at which the precipitation of the liquid substance starts, and varies depending on the composition of the fluidizing gas, the polymerization pressure and other polymerization conditions. In the present invention, the dew point of the flowing gas is usually 20 to 80 ° C, preferably 40 to 70 ° C. From the viewpoint of the efficiency of cooling the inner wall of the reactor, it is preferable to increase the dew point of the flowing gas. Examples of the method of increasing the dew point of the flowing gas include a method of increasing the concentration of the condensable gas in the flowing gas. Examples of condensable gases include butane,
Saturated aliphatic hydrocarbons having 4 to 10 carbon atoms such as normal butane, isobutane, pentane, normal pentane, isopentane, hexane, octane and decane, pentene-1,4-
Methyl pentene-1, hexene-1, octene-1, decene-1
And unsaturated aliphatic hydrocarbons having 4 to 10 carbon atoms.

As the polymerization conditions, the polymerization temperature is usually 5 to 1
00 ℃, preferably 60 ~ 95 ℃, the atomic ratio of transition metal in the solid catalyst to the organoaluminum compound (Al / M) is 1 ~ 1000
0, the polymerization pressure can usually be carried out under conditions of atmospheric pressure to 100 kg / cm ² · G.

Further, for the purpose of improving the polymerization activity, maintaining the shape of the produced polymer, facilitating the introduction of the catalyst into the polymerization reactor, preventing the catalyst from adhering to the polymerization reactor, and improving the fluidity in the fluidized bed reactor. For example, ethylene or a certain amount of ethylene and another olefin can be preliminarily polymerized, and then the prepolymer can be used as a catalyst in the main polymerization. Prepolymerization is, for example, in a slurry method in an inert hydrocarbon solvent, usually, the polymerization temperature 5 ~ 80 ℃, preferably 10 ~ 80 ℃, polymerization time
It is carried out for 5 to 60 minutes under the condition that 1 to 100 g of the polymer is obtained per 1 mg atom of the transition metal in the catalyst solid.

An embodiment of the present invention will be schematically described with reference to FIG. The gas phase reaction mixture is polymerized in the gas phase fluidized bed portion 1 of the reactor, withdrawn from the top of the reactor, and reintroduced from the bottom of the reactor through the circulation line 5 via the heat exchanger 6 and the compressor 7. To be done. Replenishment feedstock
It is supplied from the raw material supply line 8. The prepolymer preliminarily polymerized with a small amount of olefin in a catalyst or another container is supplied from a supply line 12. The produced polymer is continuously or intermittently withdrawn from the reactor by the withdrawal line 13 so that the height of the gas phase fluidized bed portion becomes constant. The inner wall of the reactor is cooled below the dew point of the flowing gas by a cooling device 14 attached to the outer wall of the reactor. The cooling device is attached to the bottom of the reactor up to a height about 1 to 2 times the diameter of the reactor.

[0031]

According to the method of the present invention, when a polymer is produced in a fluidized bed reactor, the temperature inside the fluidized bed is destabilized due to local accumulation of heat of polymerization, and is formed on the inner wall of the polymerization reactor. Prevents electrostatic adhesion of polymers and generation of lumps,
Gas phase polymerization can be stably carried out.

[0032]

【Example】

Example 1 Synthesis of Support Solid-1 Toluene 262 was added to a 1 L glass reactor pre-filled with nitrogen equipped with a mechanical stirring system and double jacket.
26 ml of triethylaluminum and 26 ml of
While maintaining at 0 ° C, 12 mmol of tert-butyl alcohol was added. To this mixture, a solution of diisoamyl ether containing 60 mmol of n-butylmagnesium chloride 4
0.2 ml was added. 66 mmol of tert-butyl chloride
The temperature was raised to 40 ° C. in 5 minutes and the mixture was added dropwise. Furthermore, 40 ℃
The reaction was carried out for 5 hours while maintaining The formed carrier solid was separated by filtration, and once with 50 ml of toluene and further with 50 ml of n-heptane.
After washing twice, it was dried under reduced pressure at 40 ° C. for 2 hours. The obtained carrier solid was spherical particles having a relatively narrow distribution with a particle size (radius) of 30 to 40 μm.

(Synthesis of solid catalyst) 5 g of the obtained carrier solid was slurried in 75 ml of toluene, and 75 mM of methyltriethoxysilane was added as an electron donor, and the mixture was stirred at 40 ° C. for 30 minutes and then tetrachlorotitanium. And add 100 mM
The mixture was stirred at 40 ° C for 60 minutes. Then the solid is filtered off and
Washed 3 times with 3 ml of toluene and once with 50 ml of heptane and dried the solid. The Ti content of the obtained spherical solid is 0.97%,
The Al content was 0.61% and the Mg content was 15.7%.

(Preliminary Polymerization) Made of SUS filled with nitrogen gas
A 2-liter autoclave was charged with 800 ml of n-heptane, and tri-
7.5 mM n-octylaluminum, 2.5 mM triethylaluminum and the above catalyst solid (titanium content 2.5 mM) were added. After hydrogen gas of 1.5 kg / cm ² · G was injected under pressure, the mixture was introduced up to 60 ° C to initiate polymerization. Keep the temperature at 67-80 ° C during the polymerization, and introduce ethylene at 1 L / min.
Polymerization was carried out until 0 g of prepolymer was produced.

(Vapor phase copolymerization of ethylene and butene-1) Using the fluidized bed reactor shown in FIG.
Was copolymerized with. As the polymerization catalyst, a catalyst system composed of the solid catalyst prepared by the method described above and tri-n-octyl-aluminum was used. The composition of the flowing gas is ethylene: 35.0vol%, ethane: 3.0vol%, butene-
1: 17.5vol%, pentane: 6.0vol%, hydrogen: 7.0vol%,
Nitrogen: Consists of 27.0 vol% and had a dew point of 60.0 ° C. Polymerization pressure: 25.0kg / cm ² · G, Polymerization temperature: 82 ℃, Gas flow rate: 6
Polymerization was carried out under the conditions of 0.0 cm / s and STY: 62.5 kg / m ³ .
Polymerization was carried out by adjusting the inner wall temperature of the fluidized bed reactor to 55 ° C. by a cooling device attached to the fluidized bed reactor from the bottom of the reactor to a height 1 to 2 times the diameter of the reactor. Polymerization could be carried out stably, and no adhesion of polymer particles to the inner wall was observed.

Examples 2 to 3 Polymerization was carried out in the same manner as in Example 1 except that the polymerization conditions shown in Table 1 were used. However, the polymerization could be stably carried out and the polymer particles on the inner wall No adhesion was observed.

Comparative Example Polymerization was carried out in the same manner as in Example 1 except that the inner wall of the fluidized bed reactor was not cooled. The temperature in the fluidized bed reactor during the polymerization fluctuated unstablely, such as a sharp rise. In addition, adhesion of polymer particles to the inner wall of the fluidized bed reactor was observed.

[0038]

[Table 1]

[Brief description of drawings]

FIG. 1 is a drawing showing an embodiment of the present invention. Explanation of symbols 1 ... Gas phase fluidized bed part of reactor 2 ... Fluidized bed cylinder 3 ... Calming compartment 4 ... Fluidization grit 5 ... Circulation line 6 ... Heat exchanger 7 ... Compressor 8 ...・ Raw material supply line 9 ・ Preliminary polymer supply line 10 ・ ・ Polymer extraction line 11 ・ ・ Cooling device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadaoki Shinoda 8-1 Goi Minami Coast, Ichihara City, Chiba Ube Industries Ltd. Chiba Petrochemical Factory

Claims (1)

[Claims] 1. A method of continuously vapor-phase polymerizing an olefin in a fluidized bed reactor, wherein the temperature of the inner wall of the reactor is cooled to below the dew point of the fluidized gas during the polymerization.