JP3877400B2 - Polyolefin production method and production apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a production method and a production apparatus for producing polyolefin by a multistage gas phase polymerization method in which at least two reaction vessels are continuously used.
[0002]
[Prior art]
In general, when a polymer is produced in one polymerization vessel, the properties of the obtained polymer are limited to a certain range. In addition, as market demands diversify, when products with more complex physical properties are desired, a method of connecting a plurality of polymerizers and producing a polymer having different properties in each polymerizer is adopted. It has become like this.
[0003]
This method is also applied to gas phase polymerization, and as such a polymerization apparatus, for example, as shown in FIG. 2, a first reaction tank 111 and a second reaction tank 121 are provided. A two-stage gas phase polymerization apparatus is mentioned.
[0004]
The solid catalyst A is supplied to the first reaction tank 111 from the supply line 115, and gaseous olefin is supplied from the supply line 112 through the blower 113 from the bottom of the first reaction tank 111. The supplied gaseous olefin passes through a dispersion plate 117 made of a perforated plate or the like disposed near the bottom of the first reaction tank 111 to form a fluidized bed 118, and this fluidized bed 118 is maintained in a fluidized state. To do. At this time, a polymerization reaction is performed in the fluidized bed 118.
[0005]
The produced polymer particles are continuously extracted and separated into solid and gas by the purge bins 131 and 132. At this time, the valves 133 and 134 are appropriately controlled to open and close. When the valve 135 is opened, the polymer powder thus obtained is discharged to the transport line 125 and sent to the second reaction tank 121 through the transport line.
[0006]
In addition, the unreacted gaseous olefin and the like that have passed through the fluidized bed 118 are reduced in flow rate in the deceleration region 119 provided in the upper part of the first reaction tank 111, and are placed in the upper part of the first reaction tank 111. It is discharged out of the first reaction tank 111 through the provided gas outlet. The unreacted gaseous olefin discharged from the first reaction tank 111 is cooled by the heat exchanger (cooling device) 114 through the circulation line 116, merged with the supply line 112, and then blown by the blower 113. Again, it is continuously fed into the fluidized bed 118 in the first reaction tank 111.
[0007]
On the other hand, the polymer powder is sent to the second reaction tank 121 from the first reaction tank 111 via the transport line 125, and olefin gas is supplied from the supply line 122 via the blower 123. At this time, the fluidized bed 128 is formed in the second reaction tank 121 together with the polymer powder, the olefin gas, and the solid catalyst contained in the polymer powder, and further polymerization reaction is performed here.
[0008]
The resulting polyolefin is continuously withdrawn from line 126.
Further, the transfer line 125 branches from the supply line 122 and the other end is connected to the upper side of the second reaction tank 121. A gas containing olefin sent from the supply line 122 is supplied to the centrifugal blower 141. The pressure is raised by a pressure raising means such as the above, and the polymer powder extracted from the first reaction tank 111 is conveyed and introduced into the second reaction tank 121.
[0009]
[Problems to be solved by the invention]
By the way, in the above-mentioned method, not only the equipment cost increases significantly by using a booster such as a centrifugal blower for the conveying line 125, but also the piping for the polymer powder conveying line, the oil unit of the blower shaft seal portion, etc. Equipment becomes complicated.
[0010]
In general, when a booster such as a centrifugal blower is used, it is necessary to prepare a spare booster in consideration of the equipment malfunction. Therefore, problems such as the above-described cost and complications related to equipment piping arise for each boosting equipment, complicating the problem.
[0011]
Therefore, the present invention has been made in view of the above circumstances, and when performing polyolefin gas phase polymerization in a multistage polymerization system of two or more stages, the powder obtained in the first stage reaction tank is the second stage. It is an object of the present invention to provide a polyolefin production method and production apparatus capable of efficiently transporting polymer powder without the need for special pressurizing means and equipment piping to be transported to the reaction tank.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a polyolefin according to the present invention is a method for producing a polyolefin by a multistage gas phase polymerization method using at least two reaction vessels in succession,
A first polymerization step of polymerizing olefin in a first reaction tank to obtain a polyolefin powder;
An extraction step of taking out the polyolefin powder from the first reaction tank via an extraction line ;
A transport step of transporting the polyolefin powder taken out in the take-out step to a second reaction tank following the first reaction tank by a transport medium via a transport line;
A second polymerization step of performing a polymerization reaction using the polyolefin powder and a gaseous monomer supplied thereto in the second reaction tank;
A supply step of supplying a gaseous monomer to the second reaction tank via a supply line;
Branched from the supply line, connected to the extraction line in the middle, the other end connected to the upper side of the second reaction tank , and the supply line side to the supply line side from the connection point with the extraction line Polyolefin taken out in the above-mentioned extraction step through a conveyance line having flow rate measuring means for measuring the flow rate of the conveyance medium in order from the line side and a valve for adjusting the flow rate of the conveyance medium on the downstream side of the flow rate measurement means. the powder conveying medium and a conveying step of conveying to the second reaction vessel subsequent to the first reaction vessel above,
When part of the gas containing the monomer supplied to the second reaction tank is used as the transfer medium and the polyolefin powder is transferred from the first reaction tank to the second reaction tank The pressure loss of the transport medium in the transport line is adjusted to the flow rate of the transport medium by adjusting the opening of the valve based on the measurement result of the flow meter, and supplied to the second reaction tank. Is set to be smaller than the sum of pressure losses in each of the fluidized bed formed in the second reaction tank of the gas containing the monomer and the dispersion plate disposed below the fluidized bed. .
[0013]
Further, the inside of the second reaction tank is preferably configured such that the ratio of the height of the fluidized bed from the dispersion plate to the inner diameter of the second reaction tank in the vicinity of the dispersion plate is 2 or more. .
[0014]
Moreover, in the said extraction process, it is preferable to isolate | separate the product taken out from the 1st reaction tank into the solid part and the gas part, and to send the polyolefin powder which is a solid part to the said conveyance line.
[0015]
Moreover, in the said conveyance process, it is preferable to introduce | transduce the said polyolefin powder into the gas area | region of the said fluidized bed upper part provided in the upper part in a said 2nd reaction tank.
[0016]
The polyolefin production apparatus according to the present invention is a production apparatus for producing a polyolefin by a multistage gas phase polymerization method using at least two reaction tanks continuously,
A first reactor for obtaining polyolefin powder from olefins using a catalyst;
An extraction line for taking out the polyolefin powder from the first reaction tank;
Polyolefin powder taken out in the take-out line,
A second reaction tank following the first reaction tank in which a polymerization reaction is performed using a gaseous monomer supplied thereto;
A supply line for supplying the gaseous monomer to the second reaction tank; a branch from the supply line; and connected to the outlet side of the extraction line in the middle; The ends are connected,
A transport line for transporting the polyolefin powder taken out in the take-out line to the second reaction tank by a transport medium sent from the supply line;
A flow rate measuring means for measuring the flow rate of the transport medium in order from the supply line side to the supply line side from the connection point with the take-out line, and a downstream side of the flow rate measurement means. A valve for adjusting the flow rate of the carrier medium ,
The second reaction tank includes a height of the fluidized bed formed on the dispersion plate disposed in the second reaction tank from the dispersion plate, and the second reaction tank in the vicinity of the dispersion plate. The ratio to the diameter of the straight body is 2 or more,
The pressure loss of the transport medium in the transport line when transporting the polyolefin powder taken out in the take-out line is adjusted based on the measurement result of the flow meter to adjust the opening of the valve. The flow rate is controlled to make it smaller than the sum of pressure losses in the fluidized bed and the dispersion plate of the gaseous monomer supplied to the second reaction tank.
[0017]
Moreover, it is preferable to arrange solid-gas separation means for separating the product taken out from the first reaction tank into a solid part and a gas part on the take-out line.
Also, on the transfer line, from the connection point with the take-out line to the supply line side, in order from the supply line side,
Flow rate measuring means for measuring the flow rate of the carrier medium;
It is preferable to dispose a valve for controlling the flow rate of the transport medium on the downstream side of the flow rate measuring means.
[0018]
Moreover, it is preferable to connect one end of the said conveyance line to the gas area | region of the said fluidized bed upper part provided in the upper part in said 2nd reaction tank.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a polyolefin production method and production apparatus according to the present invention will be described with reference to the drawings.
[0020]
In the present invention, the term “polymerization” may be used to mean not only homopolymerization but also copolymerization, and the term “polymer” refers not only to homopolymers but also to copolymerization. It may be used in the meaning that also includes coalescence.
[0021]
FIG. 1 is a schematic view showing an example of the configuration of the polyolefin production apparatus. As shown in FIG. 1, this polyolefin production apparatus comprises a first reaction tank 1 for polymerizing olefins using a catalyst to obtain a polyolefin powder, and the polyolefin powder from the first reaction tank 1. An extraction line 30 to be removed;
A first reactor tank 1 following the first reaction tank 1 that performs a polymerization reaction using the polyolefin powder taken out in the take-out line 30, the catalyst contained in the powder, and the newly supplied gaseous monomer is used. The second reaction tank 11, the supply line 12 for supplying the gaseous monomer to the second reaction tank 11, and the polyolefin powder taken out in the take-out line 30 by a carrier medium sent from the supply line 12 A transport line 15 for transporting to the second reaction tank 11 is provided. The transfer line 15 branches from the supply line 12 and is connected to the outlet side of the take-out line 30 in the middle, and the other end is connected to the upper side of the second reaction tank 11.
[0022]
Here, the first polymerization vessel 10 supplies the solid catalyst A for polymerization from the line 5 into the first reaction vessel 1 and supplies the gaseous monomer from the supply line 2 to the first reaction vessel 1 through the blower 3. The gaseous monomer is sent above the dispersion plate 7. Above the dispersion plate 7, a fluidized bed 8 is formed using the gaseous monomer to be sent and the solid catalyst A, and the fluidized bed (reaction system) 8 is maintained in a fluidized state, while the fluidized bed 8. The polymer or copolymer particles or powder is obtained by a first-stage gas phase polymerization reaction.
[0023]
Here, the gaseous monomer is one or more monomers (monomer, comonomer) that are polymerized by the action of the solid catalyst for polymerization, such as olefin gas, and the polymerization system has a molecular weight control agent such as hydrogen, It may be supplied together with an inert gas such as nitrogen or hydrocarbon.
[0024]
On the other hand, the unreacted gaseous monomer that has passed through the fluidized bed 8 has its flow velocity reduced in the deceleration region 9 provided in the upper part of the first reaction tank 1, and the upper part of the first reaction tank 1. It is discharged out of the first reaction tank 1 through a gas outlet provided in the.
[0025]
In addition, since it is necessary to remove the heat of polymerization reaction before the discharged gaseous monomer is supplied again into the fluidized bed 8, a heat exchanger 4 is provided on the circulation line 6. It cools by passing through the heat exchanger 4 and joins with the supply line 2.
[0026]
Further, the polyolefin powder generated by the polymerization reaction proceeding in the fluidized bed 8 is sent to the take-out line 30.
The extraction line 30 has one end connected to the first reaction tank 1 and the other end connected to a transfer line 15 to be described later. Here, a valve 23, a purge bin 21, a valve 24, A purge bin 22 and a valve 25 are arranged in this order.
[0027]
The product from the first reaction tank 1 sent to the extraction line 30 is separated (solidified) into a solid part (polyolefin powder) and a gas part (gaseous monomer, etc.) by two purge bins 21 and 22. Only the solid portion obtained by this solid-gas separation operation by the operation of a valve 25, for example, a rotary valve, is discharged to the conveying line 15. The solid part of the polyolefin powder is sent to the second reaction tank 11 by a flow of a carrier medium described later.
[0028]
Here, the reason why the purge bins are provided in two stages is to ensure solid-gas separation, and the number of stages is not limited. Further, the gas portion can be combined with the circulation line 6 through a line (not shown), and supplied to the fluidized bed 8 again.
[0029]
Similarly to the first reaction tank 1, the second reaction tank 11 blows gaseous monomer from the supply line 12 to the bottom of the second reaction tank 11 by the blower 13 to disperse the gaseous monomer. It is sent above the plate 17. Above the dispersion plate 17, a fluidized bed 18 is formed using the gaseous monomer to be sent, the polyolefin powder introduced from the transport line 15, and the solid catalyst for polymerization contained in the polyolefin powder. While maintaining the fluidized bed 18 in a fluidized state, a polymer or copolymer is obtained by a further gas phase polymerization reaction in the fluidized bed 18.
[0030]
Here, the gaseous monomer is one or more monomers (monomer, comonomer) which are polymerized by the action of the solid catalyst for polymerization as described above, and a molecular weight control agent such as hydrogen is used for the polymerization system. Alternatively, it may be supplied together with an inert gas such as nitrogen or hydrocarbon.
[0031]
On the other hand, the flow rate of the unreacted gaseous monomer that has passed through the fluidized bed 18 is reduced in the deceleration region 19 provided in the upper part of the second reaction tank 11, and the upper part of the second reaction tank 11. It is discharged out of the second reaction tank 11 through a gas outlet provided in the tank. Further, since it is necessary to remove the heat of polymerization reaction before the discharged gaseous monomer is supplied again into the fluidized bed 18, a heat exchanger 14 is provided on the circulation line 16. It cools by passing through the heat exchanger 14 and joins the supply line 12.
[0032]
Then, the polyolefin produced by the progress of the polymerization reaction in the fluidized bed 18 is taken out from the line 40.
Further, the transfer line 15 branches from the supply line 12 on the outlet side of the blower 13 and is connected to the take-out line 30 in the middle. Further, the end of the transfer line 15 is above the second reaction tank 11, for example, the gas above the fluidized bed. Connected to the area. Between the branch point from the supply line 12 and the contact point with the take-out line 30, a flow meter 31 for measuring the flow rate of the transport medium and a valve 32 for adjusting the flow rate of the transport medium are arranged in order.
[0033]
The flow meter 31 and the valve 32 are provided to control the pressure loss of the transport medium in the transport line, and based on the measurement result of the flow meter 31 in order to keep the pressure loss constant. It is preferable to control the flow rate of the transport medium by adjusting the opening of the valve 32. The opening / closing control may be automatic or manual.
[0034]
Here, the said polyolefin manufacturing method performed using the said polyolefin manufacturing apparatus is demonstrated corresponding to the effect | action of the apparatus shown in FIG.
The production method includes a first polymerization step of polymerizing an olefin in the first reaction vessel 1 to obtain a polyolefin powder, an extraction step of taking out the polyolefin powder from the first reaction vessel 1, and an extraction step. A conveying step of conveying the taken-out polyolefin powder to a second reaction tank 11 following the first reaction tank 1 by a conveying medium via a conveying line 15; and presence of the polyolefin powder in the second reaction tank 11 And a second polymerization step in which a polymerization reaction is performed using the gaseous monomer supplied here.
[0035]
In the above manufacturing method, when the first polymerization reaction is performed in the first polymerization vessel 10 as described above and a polyolefin powder is generated, the polyolefin powder is introduced into the take-out line 30.
[0036]
In the take-out line 30, the solid portion and the gas portion are separated by the purge bins 21 and 22 which are two solid-gas separation means, and the separated polyolefin powder is introduced into the transport line by the operation of the valve 25.
[0037]
In the conveyance line 15, the polyolefin powder introduced from the take-out line 30 is conveyed by the flow of the conveyance medium, and is introduced into the gas region in the straight barrel section above the second reaction tank 11, for example, above the fluidized bed. Is done. This carrier medium is a part of the gaseous monomer or the like supplied to the second reaction tank 11.
[0038]
In the second reaction tank 11, the polyolefin powder introduced from the transfer line 15, the solid catalyst contained in the powder, and the gaseous monomer sent from the supply line 12 are disposed above the dispersion plate 17. A fluidized bed 18 is formed. While the fluidized bed 18 is maintained in a fluidized state, second-stage polymerization is performed, and a polyolefin is obtained and taken out from the line 40.
[0039]
Here, the second reaction tank 11 includes a fluidized bed height H of the fluidized bed 18 formed on the dispersion plate 17 from the dispersion plate 17 and the second reaction tank in the vicinity of the dispersion plate 17. 11 (H / D) with the diameter D of the straight body portion is 2 or more, preferably 2 to 6, and more preferably 3 to 6.
[0040]
The height H of the fluidized bed is determined by measuring the difference between the pressure immediately above the dispersion plate 17 and the pressure in the gas region, for example, the deceleration region, above the fluidized bed. It is obtained by dividing by the bulk density AD (ΔP / AD).
[0041]
In this way, the pressure loss [Delta] P ₁ at the time of conveying the polyolefin powder withdrawn by extraction line 30 of the transfer medium, said second reaction vessel 11 the gaseous monomer is fed to the The sum of pressure losses ΔP ₂ in each of the fluidized bed 18 and the dispersion plate 17 can be made smaller, that is, ΔP ₁ <ΔP ₂ .
[0042]
More specifically, the pressure loss ΔP ₁ is the pressure loss during transportation of the polyolefin powder of the transport medium supplied from the supply line 12 via the transport line 15, that is, between point a and point b. It is the powder transport pressure loss. The sum of the pressure loss ΔP _{2 is} the sum of the dispersion plate pressure loss and the fluidized bed pressure loss between point d and point c.
[0043]
As described above, since ΔP ₁ <ΔP ₂ , the pressure of the gas during the transfer of the polyolefin powder in the transfer line 15 becomes higher than the pressure of the gas in the second reaction tank 11. The polyolefin powder can be smoothly conveyed from the take-out line 30 to the second reaction tank 11 without providing a special pressure raising means such as a blower or equipment piping in the line. Further, as described above, one end of the transfer line 15 is connected to the gas region of the straight body portion in the second reaction tank 11 so that the polyolefin powder is introduced into the gas region of the straight body portion. By comprising, polyolefin powder can be conveyed more effectively.
[0044]
As mentioned above, the gas containing the monomer which supplies the polyolefin powder produced | generated by the 1st reaction tank 1 to the 2nd reaction tank 11 by comprising the manufacturing method and apparatus of the polyolefin concerning this invention. When a part of the above is used for transporting to the second reaction tank 11, instead of using a conventional pressurizing means such as a centrifugal blower, a single quantity supplied directly to the second reaction tank 11 Since the method of adjusting the pressure loss of the gas containing the body and the pressure loss of the gas containing the monomer used for the above transportation is used, the piping equipment is simplified, the equipment cost is reduced, and the apparatus The operation became easier.
[0045]
Of course, the present invention can also be applied to multistage gas phase polymerization of three or more stages. In this case, it is particularly effective in terms of simplifying the device configuration, reducing equipment costs, and facilitating device operation.
[0046]
Therefore, by using the above-described manufacturing apparatus, it is possible to plan according to the market demand for diversifying the properties of the obtained polyolefin, and to manufacture such polyolefin easily and inexpensively with a simple apparatus. .
[0047]
Although preferred embodiments of the present invention have been described, the present invention is not limited thereto, and various modifications can be made without departing from the object of the present invention.
[0048]
【The invention's effect】
According to the polyolefin production method and production apparatus according to the present invention, the polyolefin powder produced in the first-stage reaction tank, using a part of the gas containing the monomer to be supplied to the second-stage reaction tank, When transporting to the second-stage reaction tank, the pressure loss of the gas containing the monomer supplied directly to the second-stage reaction tank is used instead of using a conventional booster such as a centrifugal blower. And the pressure loss of the gas containing the monomer used for the conveyance are used, the piping equipment is simplified, the equipment cost is reduced, and the operation of the apparatus is facilitated.
[0049]
Furthermore, one end of the transfer line is connected to the upper part of the fluidized bed in the second reaction tank, for example, the gas region of the straight body part, and the polyolefin powder is introduced into the fluidized bed. The polyolefin powder can be conveyed more effectively.
[0050]
Moreover, the flow rate of the gaseous monomer used for the said conveyance is arrange | positioned by adjusting the opening degree of a valve based on the flow volume of the conveyance medium measured with a flow meter by providing a flow meter and a valve in the said conveyance line. Loss can be easily adjusted.
[0051]
According to the present invention, it is possible to plan according to the market demand for diversifying the properties of the obtained polyolefin, and to manufacture such polyolefin easily and inexpensively with a simple apparatus.
[0052]
【Example】
The present invention will be described more specifically in the following examples, but the present invention is not limited to these examples.
[0053]
Using the apparatus shown in FIG. 1, first, a polymerization catalyst and ethylene gas were continuously supplied to the first reaction tank 1, and polymerization was continued at 80 ° C. The produced ethylene polymer was withdrawn at a rate of 100 kg / hr and solid-gas separated with purge bottles 21 and 22. The obtained polyethylene powder was sent to a conveying line 15 having a diameter of 0.05 m and a gas flow rate of 100 m ³ / hr, and supplied to the second reaction tank 11.
[0054]
The second reaction tank 11 has a straight body portion having a diameter of 1 m, ethylene gas is blown from the bottom at 2000 m ³ / hr to form a fluidized bed, polymerization proceeds at 80 ° C., and the generated ethylene heavy The coalescence was extracted at a rate of 160 kg / hr.
[0055]
At this time, the pressure in the vicinity of the dispersion plate 17 was 20 kg / cm ² · G, and the gas pressure in the upper part of the second reaction tank 11 was 20.14 kg / cm ² · G. Further, the powder bulk density of the polyolefin powder was 460 kg / m ³ . Thereby, the height H of the formed fluidized bed was calculated as 3 m, and H / D = 3.
[0056]
Further, the pressure loss of the fluidized bed was 900 mmH ₂ O, the pressure loss in the vicinity of the dispersion plate 17 was 500 mmH ₂ O, that is, the sum ΔP ₂ of the pressure loss between d and c was 1400 mmH ₂ O. On the other hand, the pressure loss ΔP ₁ between a and c was 1000 mmH ₂ O.
[0057]
In this polyolefin production apparatus, the polyolefin powder could be smoothly and effectively conveyed without using the pressurizing means for the conveying line.
[Brief description of the drawings]
FIG. 1 is a schematic view showing one specific embodiment of the polyolefin production apparatus of the present invention to which the polyolefin production method of the present invention is applied.
FIG. 2 is a schematic diagram showing a conventional polyolefin production apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st reaction tank 10 1st superposition | polymerization device 11 2nd reaction tank 12 Supply line 15 Conveyance line 20 2nd superposition | polymerization devices 21 and 22 Purge bottle 30 Extraction line 31 Flowmeter 32 Valve

Claims (7)

In a method for producing a polyolefin by a multistage gas phase polymerization method using at least two reaction vessels in succession,
A first polymerization step of polymerizing olefin in a first reaction tank to obtain a polyolefin powder;
An extraction step of taking out the polyolefin powder from the first reaction tank via an extraction line ;
A second polymerization step of performing a polymerization reaction using the polyolefin powder and a gaseous monomer supplied thereto in the second reaction tank;
A supply step of supplying a gaseous monomer to the second reaction tank via a supply line;
Branched from the supply line, connected to the extraction line in the middle, the other end connected to the upper side of the second reaction tank , and the supply line side to the supply line side from the connection point with the extraction line Polyolefin taken out in the above-mentioned extraction step through a conveyance line having flow rate measuring means for measuring the flow rate of the conveyance medium in order from the line side and a valve for adjusting the flow rate of the conveyance medium on the downstream side of the flow rate measurement means. the powder conveying medium and a conveying step of conveying to the second reaction vessel subsequent to the first reaction vessel above,
When part of the gas containing the monomer supplied to the second reaction tank is used as the transfer medium and the polyolefin powder is transferred from the first reaction tank to the second reaction tank The pressure loss of the transport medium in the transport line is adjusted to the flow rate of the transport medium by adjusting the opening of the valve based on the measurement result of the flow meter, and supplied to the second reaction tank. Is set to be smaller than the sum of pressure loss in each of the fluidized bed formed in the second reaction tank of the gas containing the monomer and the dispersion plate disposed below the fluidized bed. Production method of polyolefin. The inside of the second reaction tank is configured such that the ratio of the height of the fluidized bed from the dispersion plate to the inner diameter of the straight body portion of the second reaction tank in the vicinity of the dispersion plate is 2 or more. The method for producing a polyolefin according to claim 1.   The product extracted from the first reaction vessel is separated into a solid portion and a gas portion in the extraction step, and the polyolefin powder as the solid portion is sent to the transport line. Process for producing polyolefins.   2. The method for producing a polyolefin according to claim 1, wherein in the transporting step, the polyolefin powder is introduced into a gas region in the upper part of the fluidized bed provided in an upper portion of the second reaction tank. . A production apparatus for producing polyolefin by a multi-stage gas phase polymerization method using at least two reaction vessels in succession,
A first reactor for obtaining polyolefin powder from olefins using a catalyst;
An extraction line for taking out the polyolefin powder from the first reaction tank;
A second reaction tank following the first reaction tank in which a polymerization reaction is performed using the polyolefin powder taken out in the take-out line and the gaseous monomer supplied thereto,
A supply line for supplying gaseous monomer to the second reaction vessel;
Branched from the supply line, connected to the outlet side of the extraction line in the middle, the other end connected to the upper side of the second reaction tank, and the polyolefin powder taken out in the extraction line was supplied to the supply line A transport line for transporting to the second reaction tank by a transport medium sent from the line;
A flow rate measuring means for measuring the flow rate of the transport medium in order from the supply line side to the supply line side from the connection point with the take-out line, and a downstream side of the flow rate measurement means. A valve for adjusting the flow rate of the carrier medium ,
The second reaction tank includes a height of the fluidized bed formed on the dispersion plate disposed in the second reaction tank from the dispersion plate, and the second reaction tank in the vicinity of the dispersion plate. The ratio to the diameter of the straight body is 2 or more,
By adjusting the opening of the valve based on the measurement result of the flow meter , the pressure loss of the transport medium in the transport line when transporting the polyolefin powder taken out by the take-out line , and the transport medium The polyolefin production apparatus is characterized in that the flow rate of the gaseous monomer is controlled to be smaller than the sum of pressure losses in the fluidized bed and the dispersion plate of the gaseous monomer supplied to the second reaction tank.   6. The polyolefin production apparatus according to claim 5, wherein solid-gas separation means for separating the product taken out from the first reaction tank into a solid part and a gas part is disposed on the take-out line. .   The polyolefin production apparatus according to claim 5, wherein one end of the transfer line is connected to a gas region in the upper part of the fluidized bed provided at an upper portion in the second reaction tank.

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