JPS6018502A - Polymerization reactor - Google Patents

Abstract

PURPOSE:To provide a polymerization reactor capable of giving granular polyolefin without producing block product, and consisting of a reactor having variable-speed stirring blades, a granule circulation tank furnished with a cooling device at the outside and variable-speed stirring blades in the tank, and a connecting pipe and a granular medium supplying pipe connecting said reactor with said circulation tank. CONSTITUTION:A granular polyolefin is produced with a horizontal polymerization reactor consisting of a granule-stirring tank capable of given granules as the reaction product. The reactor is composed of (A) the main body 1 of the reactor having a feeding port 21 of the reaction materials at one end, a delivery port 30 of the reaction product at the other end, and the stirring blades 3 connected to the variable-speed driving means 6 and performing the stirring, mixing and transfer of the granules in the main body 1 and (B) the main body 7 of the granule circulation tank having a cooling jacket 8 at the outside of the body and stirring blades 9 connected to the variable-speed driving means 12 and performing the stirring, mixing and transfer of the granules in the tank 7. The delivery end of the reactor 1 is connected with an end of the main body 7 of the granule circulation tank through a connection pipe 22, and the other end of the main body 7 of the granule circulation tank is connected to the main body 1 of the reactor at plural positions distributed along the length of the reactor 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a polymerization reactor for obtaining powder or granules as a reaction product.

[Background of the invention]

An example of a conventional technique for obtaining an olefin polymer by supplying an olefin monomer in the presence of a powdery olefin polymer and a catalyst is disclosed in Japanese Patent Publication No. 47-11.
There is a method for producing a propylene polymer disclosed in No. 489.

The second method is to supply propylene monomer and a catalyst as necessary to the lower part of a vertical stirred tank type polymerization vessel holding powdery propylene polymer, and polymerize it to form a propylene polymer. This is the way to get it. In this method, the propylene monomer and catalyst supplied throughout the polymerization vessel are
Because this is not dispersed, propylene monomer (X) rapidly polymerizes in places where the catalyst temperature is locally high, and
Since polymerization is accompanied by significant heat generation, so-called hot spots may occur, and the resulting granular propylene polymers may fuse together to form large lumps. This block-shaped polymer causes a decrease in quality, and also has problems such as clogging the stirring blades and the tank wall of the polymerization vessel, causing an operation stoppage.

In addition, as other prior art, Japanese Patent Application Laid-Open No. 51-86584
There is a horizontal stirred tank type polymerization reactor disclosed in JP-A-51-86585. This polymerization reactor is divided into two or more small chambers for polymerization, the polymer bed is mixed using stirring blades, and the interior of the polymerization reactor is made subfluid by blowing exhaust gas into the polymerization reactor. The liquefied solvent, Alternatively, the monomer is sprayed onto the polymer bed and the heat of reaction is removed by the heat of vaporization.Such a polymerization reactor relies on the quality of mixing of the granular polymer in the polymerization reactor. This poses a problem.In other words, when stirring and mixing powder or granular materials using stirring blades, the effect of the stirring blades is only visible on the locus in which the stirring blades are operating and in the vicinity.Therefore, the It is difficult to uniformly disperse liquids such as monomers and small amounts of solids such as catalysts supplied to a part of the surface throughout the surface, so it is necessary to install a large number of stirring blades to improve stirring and mixing. , it is necessary to increase the rotation speed of the stirring blade, but this means that
This increases power consumption and increases equipment costs.

Furthermore, since the flow of the produced polymer in the polymerization vessel to the discharge port is due to overflow, the flow of the powder and granules in the polymerization vessel as a whole is not good.

Therefore, in the conventional vertical and horizontal stirred tank type polymerization reactors, the flow within the tank becomes non-uniform, and it is difficult to prevent the formation of stagnation and block-shaped polymers that tend to form stagnation areas. As a result, the quality of the polymer deteriorates, and there are problems in that continuous operation is interrupted due to block-shaped polymers getting caught in the stirring blades and the tank wall of the polymerization vessel, resulting in operation stoppages.

Furthermore, as another conventional technique for producing a reactant to obtain a powdered body as a reaction product, there is a vertical fluidized bed type method disclosed in JP-A-54-142192; Chilled gas is circulated for fluidization of the polymer bed and removal of heat of polymerization. The heat of polymerization is removed by sensible heat change in the cooling gas, but the heat capacity of the cooling gas is small compared to the heat of polymerization, so a large amount of gas must be circulated, and the circulation of this gas requires considerable operation. The disadvantage is that it requires expense. In addition, since the circulating gas volume is large, a gtrpl is required to collect the polymer scattered from the polymerization vessel, and since the tank is a fluidized bed, the polymer density inside the polymerization vessel is N<. In order to obtain the necessary residence time, it is necessary to increase the capacity of the polymerization vessel, which has the drawback of increasing equipment costs.

[Purpose of the invention]

The purpose of the present invention is to prevent the formation of block polymers in a polymerization reactor that produces powder or granules as a reaction product, to obtain a high quality polymer, and to provide a polymerization reactor that can operate stably and continuously. It is about providing.

[Summary of the invention]

The present invention deals with the mixing of powder and granules in the reactor, which is a drawback of conventional powder and granule stirring tank type polymerization reactors.

Improves uneven heat transfer and mixes powder and granular materials.

We have investigated the application of granular materials (hereinafter referred to as granular media) as media for adjusting heat transfer and humidity, i.e., mixed media, heat transfer media, and humidity adjusting media, to polymerization reactors. In a powder stirring tank type polymerization reactor that produces powder and granules as reaction products, a reaction material supply port is provided at one end and a reaction product outlet is provided at the other end. A stirring blade is installed inside the reactor body to which a variable speed motor is connected to transfer the powder while stirring and mixing, and a variable speed drive is connected to the inside of the powder circulation tank body, which is equipped with an external cooling jacket. The other end of the reactor body and one end of the granular material circulation tank body are connected by a connecting pipe, and the other end of the reactor body and one end of the granular material circulation tank main body are By connecting the other end and multiple locations in the longitudinal direction of the reactor body through powder medium supply pipes, the powder and granules in the reactor body are uniformly stirred and mixed, and are cooled in the powder circulation tank body. The granular medium is supplied into the reactor body to uniformly moisten the granular material and remove heat.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. In FIGS. 1 and 2, 1 is a main body of a reactor equipped with a jacket 2 through which a cooling medium such as cooling water flows, and 3 is a reactor body having a function of transporting powder and granules in the main body 1 while stirring and mixing, for example. It is a screw type stirring blade connected to the shaft 4 and driven by a variable speed motor 6 through a shaft seal [5]. 7 is a main body of a granular material circulation tank equipped with a jacket 8 through which a cooling medium flows, and 9 is, for example, a screw type stirring blade having a function of transferring the granular material, that is, the granular medium in the main body 7 while stirring and mixing it. , connected to the shaft 10,
It is driven by a variable speed motor 12 via a shaft sealing device 11. 21 is a supply pipe for supplying a slurry containing a polymer, an unreacted material (monomer), a catalyst, etc. to one end of the main body l of the reactor, and n is a supply pipe for supplying the powder from the other end of the main body l to a powder circulation tank A connecting pipe for feeding the powder into the lower part of the main body 7, β to Kan are powder medium supply pipes for supplying the powder medium from the upper part of the main body 7 into the main body L, n is a discharge pipe for taking out the powder from the other end of the main body L, A ~ 31 is a steam exhaust pipe that takes out the steam generated in the main body 1, 41 is a temperature detection section that detects i degrees inside the main body 1, and 42 is a temperature detection section 4
A temperature control device that increases or decreases the rotation speed of the stirring blade 9 via a variable speed motor according to a signal from 1; 43 to 45 are the main body l;
46 is a powder surface control device that increases or decreases the rotation speed of the stirring R3 via the variable speed motor 6 based on the signals from the powder surface detection sections 6 to 4!1. It is.

In the above-mentioned configuration, to explain the case of a wet reaction in which an exothermic reaction is performed to obtain powder as a reaction product, the powder medium cooled in the main body 7 of the powder circulation tank is supplied with the powder medium. The tubes are fed into the main body 1 of the reactor, and a slurry-beating reaction material containing polymers, monomers, catalysts, etc. is fed from the feed tube 21 and mixed and stirred. This mixing and agitation adjusts the liquid concentration of the slurry supplied from the supply pipe 21, and at the same time uniformly wets the powder and granules within the main body 1, resulting in a high monomer concentration. The formation of blocky polymers is prevented. In the main body 1, the reaction of the powder and granules in an appropriately wet state progresses, and reaction heat is generated. A part of this reaction heat is absorbed as a temperature increase of the powder medium through direct contact with the cooled powder medium supplied into the main body l from the powder medium supply pipes, and other than the reaction heat. A part of the reaction heat is absorbed by the cooling medium in the jacket 2, and the remainder of the reaction heat is absorbed as the amount of heat to evaporate a part of the liquid that moistens the powder or granular material, if necessary. Steam evaporated within the main body 1 is discharged via steam exhaust pipes 28-31. The granular medium is supplied into the main body 1 by dividing it into a plurality of locations as necessary to remove the reaction heat and to parts where the granular material tends to accumulate within the main body 1. In addition, there is a pressure detection section (
(not shown) and a pressure control valve can be provided in the steam exhaust pipe 31 to maintain the inside of the main body 1 at a predetermined pressure for operation. As a result, the reaction is promoted within the main body l, and the stirring Ha+
A part of the granular material transferred to the other end of the main body 1 while being stirred and mixed is transferred to the main body 7 of the granular material circulation tank through the communication pipe n.
The remaining part is taken out from the discharge pipe as a reaction product.

The powder and granular material supplied as a granular medium into the main body 7 of the powder and granular material circulation tank has a wet liquid content due to the consumption of unreacted monomer in the main body 1 and the evaporation of the monomer due to the reaction heat 1. Since the amount is very small, the reaction does not proceed locally and no block polymer is produced. In addition, since the inside of the main body 7 is filled with powder medium,
The heat transfer area to the powder medium by the jacket 8 can be effectively utilized, and in combination with stirring and mixing by the stirring blades 9, efficient cooling can be performed.

The temperature inside the main body 1 of the reactor is controlled by detecting the temperature inside the main body 1 by a temperature detection unit 41, and increasing or decreasing the rotation speed of the stirring R9 via the variable speed motor n by the temperature control device [42]. This is done by increasing or decreasing the amount of granular media supplied to the granular medium. In this case, if necessary, temperature detection units can be installed at multiple locations in the longitudinal direction of the main body 1, and a valve or the like can be installed on the powder medium supply pipe 24.25° from the main body 7 to increase or decrease the flow rate. The temperature within 1 can be controlled at multiple points.

In addition, the powder surface of the powder inside the main body i is detected by the powder surface detection section 0°, 5
The variable speed motor 6 is detected by the
By increasing/decreasing the rotational speed of the stirring blade 3 via the stirring blade 3 and adjusting the transfer speed of the powder inside the main body 1, the powder surface inside the main body 1 is controlled to a predetermined height. Therefore, the supply amount of the powder medium increases or decreases depending on the temperature inside the main body 1, and the surface height of the powder inside the main body i changes, but the transfer speed of the powder depends on the rotation speed of the stirring blade 3 inside the main body l. By adjusting , the height of the powder surface inside the main body l can be kept constant. Therefore, even if there is an increase or decrease in the circulation of the granular medium, the granular material held in the main body 1 and the main body 7 can be controlled to a predetermined amount.
The residence time of the powder or granular material within the main body 1 can be controlled within a predetermined range.

Another embodiment of the present invention will be explained with reference to FIG.

In FIG. 3, the same parts as in FIG. 1 are designated by the same reference numerals, and their explanation will be omitted. The wooden embodiment shows the case where the powder medium is moistened in advance and supplied to the reactor main body L, and the steam taken out from the steam discharge pipe 31 is liquefied in the condenser 51 and then passed through the connecting pipe I. After being held in the condensate receiving tank 52, a part of the condensate from the condensate delivery pump 531 is supplied between the wetting liquid sprayers provided in the main body 7 via the wetting liquid supply pipe 57, and the remaining part is supplied from the condensate discharge *hole. taken out. By spraying the wetting liquid onto the cooled granular medium in the main body 7 from the wet W@liquid sprayer enclosure, the wetting liquid is stirred and mixed with the granular medium, and this pre-stirring well causes the granular medium to The wetness can be made uniform, and a powder medium with a homogeneous wetness can be supplied to the main body 1.

In this case, even if a monomer is used as the wetting liquid,
Since the powder medium is cooled, the reaction does not substantially proceed, and even if the wetting liquid is unevenly supplied, no block-shaped polymer or the like is generated.

In the above embodiment, the reactor is horizontal and the powder circulation tank is tilted. However, it is also possible to have the same functions as described above even if the reactor and the powder circulation tank are horizontal. I can do it.

EXAMPLE A propylene polymer was produced using the apparatus shown in FIG. Polymerization reactor volume 335 l! , pressure 30-32 p/cJG, temperature 70°C, average residence time 2 hours, and
Volume of circulation tank 93 (1/, polymer circulation amount 870!/n/
h, the average temperature of the polymer on the inlet side is 70°C, and the average temperature of the polymer on the outlet side is 45°C.

9/h to the monomer propylene 'F650 in circulation tank I
.

The operation was carried out by supplying a polymerization catalyst at a rate of 5.6 F/h (in terms of solid catalyst component) and further supplying a trace amount of hydrogen as a molecular weight regulator. As a result, due to good operation, 49 to 50 Kf was produced without producing block polymers.
/h of polymer could be obtained. Note that the polymerization reactor and circulation tank were charged with polypropylene as a polymer in advance, and polymerization was started.

〔Effect of the invention〕

As described above, the present invention includes the other end of the reactor main body, which is provided with stirring blades for transporting powder and granular material while stirring and mixing;
A stirring blade for transporting the granular medium while stirring is connected to one end of the granular material circulation tank main body, and a part of the granular material taken out from the reactor main body is placed inside the granular material circulation tank main body. The powder is supplied, cooled, and supplied as a powder medium from the other end of the powder circulation tank body to multiple locations in the longitudinal direction of the reactor body, so that the powder and granules in the reactor body are uniformly distributed. In addition to being able to stir and mix, it also enables uniform wetting and heat removal, prevents the formation of block-like compounds, and provides a high-quality polymer, and is stable. It is possible to perform continuous operation.

[Brief explanation of drawings]

FIG. 1 is a schematic front view of one embodiment of a polymerization reactor according to the present invention, FIG. 2 is a side view of the same, and FIG. 3 is a schematic front view of another embodiment of the present invention. .

Claims (1)

[Scope of Claims] 1. In a powder stirring tank-type horizontal polymerization reactor for obtaining powder or granules as a reaction product, a reaction material supply port is provided at one end and a reaction product discharge port is provided at the other end. The reactor body is equipped with a stirring blade that is connected to a variable speed drive IT inside and is equipped with a stirring blade that transports the powder while stirring and mixing it, and a cooling jacket on the outside and a reactor body that is connected to a variable speed drive inside and has a stirring blade that transports the powder while stirring and mixing. a granular material circulation tank main body provided with stirring blades for transferring the granular material while stirring and mixing the reactor body, the other end of the reactor main body and one end of the granular material circulation tank main body are connected by a connecting pipe, A polymerization reactor characterized in that the other end of the powder circulation tank body and multiple locations in the longitudinal direction of the reactor body are connected through powder medium supply pipes. 2. A temperature detecting section is provided in the reactor main body, and a temperature control device is provided that increases or decreases the rotation speed of the stirring blade in the powder circulation tank main body via a variable speed drive device according to a signal from the temperature detecting section. A polymerization reactor according to claim 1 provided therein. 3. The polymerization reactor according to claim 2, wherein the temperature detection portions are installed at a plurality of locations in the longitudinal direction within the reactor main body. 4. Powder surface detection sections are provided at multiple locations in the longitudinal direction of the reactor main body, and the rotational speed of the stirring blade within the reactor main body is increased or decreased via a variable speed drive device according to the signal from the powder surface detection section. A polymerization reactor according to claim 1, which is provided with a powder surface control device. 5. The polymerization reactor according to claim 1, wherein a wetting liquid sprayer is provided within the powder circulation tank main body.