JPS59126407A - Gas-phase polymerization - Google Patents

Abstract

PURPOSE:Fine particles of polymer in the gas exhausted from the upper part of the fluidized bed are collected with a cyclone and allowed to return from a specific position to the fluidized bed polymerizer, thus enabling long-term, smooth and stable operation of olefin gas-phase polymerization to be performed. CONSTITUTION:The starting materials including olefin, catalyst and so on are subjected to gas-phase polymerization in the fluidized bed polymerizer 1 and the resultant polymer is discharged from the pipe 12. At the same time, the gas containing fine particles of the polymer is exhausted from the upper part of the fluidized bed and introduced into the cyclone 2 where the particles are collected. Then, the collected powder is allowed to return through the blower 10 to the gas-blowing space 4 formed beneath the gas-distributing plate 3 of the polymerizer and the gas is made to return back together with another gas, such as olefin, fed from the bottom of the polymerizer through the distribution plate 3 into the fluidized bed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for gas phase polymerization of olefins using a fluidized bed. In more detail, the fine powder polymer entrained in the gas discharged from the upper part of the fluidized bed is returned to the fluidized bed polymerization reactor without problems such as EJN or blockage, and smooth polymerization operation can be continued for a long period of time. This invention relates to a gas phase polymerization method.

In the present invention, the term "polymerization" is sometimes used to include not only homopolymerization but also copolymerization, and the term "polymer" is sometimes used to include not only homopolymers but also copolymers.

By improving the M transfer metal catalyst component for olefin polymerization,
As a result of the dramatic increase in the production capacity of olefin polymers per unit of transition metal, we have reached a stage where it is possible to omit the catalyst removal operation after polymerization. When using such a highly active catalyst, a method of carrying out olefin polymerization in the gas phase is attracting attention because it is the simplest to operate after polymerization.

When carrying out the gas phase polymerization, in order to proceed smoothly with the polymerization, a complete mixing type polymerization vessel such as a fluidized bed polymerization vessel or an agitated fluidized bed polymerization vessel is used, and the olefin containing catalyst is A method of carrying out polymerization while floating and fluidizing the polymer has been highly praised.

In this method, it is preferable to recycle and reuse the unreacted gas stream leaving the fluidized bed, and for this purpose, the unreacted gas stream is circulated through a cooler, a circulating gas blower, etc. The fine powder polymer containing the catalyst that is discharged along with the unreacted waste stream polymerizes in these devices and piping, forming lumps, causing problems such as reduced equipment performance and blockage. It causes.

In order to avoid such troubles, in general, when the unreacted gas leaving the fluidized bed gas phase polymerization zone is recycled, the unreacted gas flow is guided into a cyclone in advance to form a finely powdered polymer. Preferably, the finely divided polymer thus collected is circulated to the gas phase polymerization zone as soon as possible, and the undesirable progress of polymerization in the vicinity of the cyclone can cause damage to the walls ('j) and tubes. It is important to prevent problems such as blockage from occurring.

Hitherto, the method of circulating such a finely powdered polymer from a cyclone to a gas phase polymerization zone has not been studied in detail. In general, the fine powder discharged from the upper part of the fluidized bed is collected in an icron and returned to the fluidized bed by returning it from the vessel wall in the upper space of the fluidized bed or from the vessel wall in the fluidized bed forming part. Conceivable. When employing the former method in the gas phase polymerization of olefins, what happens when the fine powder is circulated? It is observed that CM becomes very large, and lumps tend to form around the cyclone, causing problems such as blockage. Further, when the latter method is adopted, the formation of lumps due to agglomeration of fine powder within the fluidized bed is observed, causing troubles such as clogging of the porous plate.

Since the finely divided polymer usually contains a highly active catalyst, it is uneconomical to dispose of it, and it is desirable to recycle it to the fluidized bed polymerizer for reuse. Therefore, the present inventors have investigated a method for circulating a finely powdered polymer that avoids the above-mentioned troubles and can be operated continuously for long periods of time without causing any problems.As a result, the present inventors have developed a method for circulating a finely powdered polymer at a specific position in a fluidized bed polymerization reactor. I came across this idea.

That is, the present invention provides a method for vapor phase polymerizing olefins using a fluidized bed polymerizer.
An olefin characterized in that the fine powder polymer collected by guiding the fine powder polymer-containing gas discharged from S to a cyclone is supplied to the gas blowing space G at the lower part of the gas distribution plate of the moving bed polymerizer. Regarding the gas phase vehicle force θmi.

In the gas phase polymerization of the present invention, it is preferable to include a catalyst formed from a transition metal catalyst component and a metal of Group 1 to Group 6 of the periodic table (λ1) and a base compound catalyst component. .

The transition metal compound catalyst component is a combination of transition metals such as titanium, sodium, chromium, and zirconium, which may be liquid or solid under the conditions of use. (It does not have to be a single compound, but may be combined with other compounds (1) or mixed. Furthermore, complex compounds with other compounds or It may be a composite compound.

A suitable transition metal compound catalyst component is a highly active component capable of producing an olefin polymer of about 5000 g or more, particularly about 8000 a or more, per mmol of transition metal, and a typical example thereof is a magnesium compound 0. A highly activated titanium catalyst component can be exemplified. For example, a solid titanium catalyst component containing titanium, magnesium and/or logen as essential components, containing amorphous magnesium halide, and having a specific surface area of preferably about 4Qm2/6 or more, particularly Preferably, a component of about 80 to about Boom2/s can be exhibited at 8/11. and electron f-te bodies, such as organic acid esters, silicate esters, acid nitrides, acid anhydrides,
It may contain ketones, acid amides, tertiary amines, inorganic acid esters, phosphoric esters, phosphorous esters, ethers, and the like. This catalyst component may contain, for example, about 0% titanium.
．． 5 to about 10 m%, especially (containing about 1 to about 8 wt%), titanium/magnesium (atomic ratio) about 1/
2 to about 1/100. Especially about 1/6 to about 1
150, halogen/titanium (atomic ratio) is about 4 to about 1
00, especially about 6 to about 80% electron donor/titanium (
Those having a molar ratio of 0 to about 101, particularly 0 to about 6 are preferred.

Many of these catalyst components have already been proposed and are widely known.

The organometallic compound catalyst component is an organometallic compound having a bond between a metal of Groups 1 to 3 of the periodic table and carbon, and specific examples include organic compounds of alkali metals and organic compounds of alkaline earth metals. Examples include metal compounds and organoaluminum compounds, such as alkyllithium alkylmagnesium halides, arylmagnesium halides, alkylmagnesium hydrides, trialkylalumhalides, alkylaluminum hydrides, alkylaluminum alkogides, and alkyllithium aluminum compounds. .

In addition to the above two components, for the purpose of adjusting stereoregularity, molecular weight, molecular weight distribution, etc., hydrogen, halogenated hydrocarbon, electron donor catalyst components, such as organic acid ester/L/1 silicate ester, carboxylic acid halide , carboxylic acid amide, tertiary amine, acid anhydride, ether, ketone, aldehyde, etc. may be used in combination.

The electron donor component may be used after forming a complex compound (or addition compound I#J) with the organometallic compound catalyst component in advance during polymerization. It may be used in the form of a complex compound (or addition compound) with the compound.

In the method of the present invention, the olefins used for polymerization include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-
Methyl-1-pentene, 3-methyl-1-pentene,
Examples include styrene, butadiene, isoprene, 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, etc., and homopolymerization or copolymerization of these can be performed within a range where gas phase polymerization is possible.

The method of the present invention can be preferably used for homopolymerization of ethylene or propylene, copolymerization of ethylene and other olefins, and copolymerization of propylene and other olefins.

Gas phase polymerization is carried out in a polymerization vessel using a fluidized bed, such as a fluidized bed polymerization vessel, an orange-stirred fluidized bed polymerization vessel, and the like.

The polymerization temperature is below the melting point of the olefin polymer, preferably about 10°C or more lower than the melting point, and about 130°C to about 130°C, particularly about 40 to 110°C.

Further, the polymerization pressure is, for example, atmospheric pressure to about 150 kg/
cm2, especially about 2 to about 70 kr)/lyn2
(7) Range 11-+J is preferred. Hydrogen optionally used during the polymerization may be used, for example, in an amount of about 0 per 17 olefins.
．． 0.001 to about 20 mol, particularly about 0.02 to about 10 mol. Furthermore, in order to remove the heat of polymerization, a liquid easily volatile hydrocarbon such as propane or butane may be supplied and vaporized in the polymerization zone.

In the case of using a transition metal compound catalyst component, an organometallic compound catalyst component, an electron donor catalyst component, etc. as described above, the transition metal compound catalyst component is approximately [ ] per reaction bed volume 1e in terms of transition metal atoms. , O Q 0 5 to about 1 mmol, especially about 0.0 0 1 to about 0.5 mmol
J moles of the organometallic compound catalyst component are preferably used in proportions such that the metal/transition metal (atomic ratio) is from about 1 to about 2000, especially from about 1 to about 500. Further, it is preferable to use the electron donor catalyst component in a proportion of 0 to about 1 mol, particularly about O to 0.5 mol, per 1 mol of the organometallic compound catalyst component.

The polymerization of olefins is preferably carried out substantially continuously.

i.e. catalyst components, olefin, optionally hydrogen,
It is industrially advantageous to adopt a method in which a diluent is continuously supplied to a polymerization vessel and polymerization is carried out while the catalyst-containing polymer is floated and fluidized by a gaseous component. In continuous polymerization, in order to maintain the amount of polymer in the polymerization vessel almost constant, the polymer is continuously (or intermittently) removed from the polymerization vessel. The unreacted gas stream (optionally including hydrogen and diluent) passing through the floating slow flow zone of the coalescence is substantially continuously discharged from the polymerization zone, entraining the finely divided polymer.

This is led to a cyclone to collect the finely divided polymer in the unreacted gas stream. The unreacted gas from which the fine powder polymer has been removed can be appropriately passed through packing equipment such as a cooler or a blower, and then circulated to the polymerization zone for reuse.

In the method of the present invention, it is desirable that the finely powdered polymer collected in the cyclone be circulated to the gas phase polymerization zone as quickly as possible so as not to cause problems such as sticking to the vessel wall or clogging. For this purpose, it is possible to circulate by natural fall, but it is desirable to adopt a method of forced circulation using a method using an RJ-tally valve, a method using a fan, a method by introducing entrained gas, etc.

During this circulation, in the present invention, circulation is performed in a gradient blowing space below the gas distribution plate of the fluidized bed polymerizer.

The circulated fine powder polymer is returned to the fluidized bed along with gas such as olefin through the distribution plate 51, but it is not returned locally to a part of the fluidized bed, but evenly through the gas distribution plate. Since it is returned, the flow state is not disturbed and a good flow state can be obtained. Furthermore, since it is circulated from the bottom of the fluidized bed, as polymerization progresses in the fluidized bed, fine powder polymer particles grow and their particle size increases, so that the amount is entrained in the exhaust gas from the top of the fluidized bed again. The load on the cyclone is reduced, and troubles such as polymer adhesion around the cyclone are reduced or avoided.

On the other hand, it is desirable that the fine powder polymer returned to the gas blowing space be kept there for as short a period of time as possible and quickly returned to the fluidized bed.

For this purpose, it is desirable that the shapes of the gas blowing space and the gas distribution plate be designed to be convenient for the circulation of the finely powdered polymer.

FIG. 1 is a schematic diagram of the vicinity of the fluidized bed polymerizer 1, in which a catalyst is supplied from a tube 9, and olefin and other gas raw materials are supplied from a tube 8 to the fluidized bed polymerizer. The olefin passes through the space dispensing plate 6 and is consumed in polymerization while causing the polymer to float and flow in the fluidized bed. Unreacted gas components are discharged from the top of the fluidized bed polymerizer 1 together with the finely powdered polymer, and are led to the cyclone 2 through a pipe 5. The finely powdered polymer collected by the cyclone 2 is returned to the gas blowing space formed at the bottom of the gas distribution plate 3 of the fluidized bed polymerizer 1 through the blower 10, and is passed through the blower 10 to the gas blowing space formed at the bottom of the gas distribution plate 3 of the fluidized bed polymerizer 1. Along with this, the gas is circulated through the gas distribution plate to the fluidized bed and used effectively.

After the exhaust gas leaving cyclone 2 is cooled down as appropriate,
It can be returned to the tube 8 and used for circulation. 1 in fluidized bed
1. The valve 11 is connected so that its height is almost constant.
and is discharged from tube 12.

In FIG. 1, a gas blowing space is formed to prevent the slightly moving polymer returned to the polymerization vessel from staying in the gas blowing space more than necessary.7. It is desired that the slope α of the percentile wall is at least 45 degrees, preferably 60 to 80 degrees. If this inclination force is too loose, finely powdered polymer tends to accumulate on the wall soil of the polymerization vessel, and there is a risk that the polymer may adhere to the vessel wall or form lumps.

Furthermore, in order to pass the finely powdered polymer through the gas distribution plate as quickly as possible, the pore size of the gas distribution plate can be made larger overall or the bottom part can be widened to make it easier to form a fluidized bed. It is desirable to be able to return it. For this purpose, for example, the pore size of the distribution plate should be at least 5 m+n, in particular 8 to 5 m, on the gas population side.
It is desirable to set it to 0 mm & degree.

Present invention 1. According to this method, there are no troubles surrounding the cyclone, the polymerization condition is good, and it is possible to carry out continuous polymerization for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a drawing showing one embodiment of the present invention. Applicant: Mitsui Petrochemical Industries, Ltd. Agent Kazu Yamaguchi

Claims (2)

[Claims] (1) In a method of gas-phase polymerizing olefin using a fluidized bed polymerization device, the fine powder polymer collected by guiding the fine powder polymer-containing gas discharged from the upper part of the fluidized bed to a cyclone is subjected to fluidized bed polymerization. A method for the gas phase polymerization of olefins, characterized in that the gas is supplied to a gas blowing space at the bottom of a gas distribution plate. (2) The method according to claim (1), characterized in that the wall portion of the polymerization vessel forming the gas blowing space below the gas distribution plate of the fluidized bed polymerization vessel has an inclination of at least 45 degrees or more. (b) The method according to claim (1), wherein the pore diameter on the gas distribution side of the lower part of the gas distribution plate is at least 5 mm or more.