JP2000344804A - Multi-stage gas-phase polymerization method and multi- stage gas-phase polymerization apparatus and apparatus to reduce the amount of entailed other components in polymer powder in multi-stage gas-phase polymerization apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-stage gas-phase polymerization method in which hydrogen gas and a comonomer are removed from a polymer powder which inhibit polymerization in a downstream fluidized-bed reactor and which make it difficult to control the properties of polymers, in transferring a polymer powder extracted from a upstream fluidized-bed reactor a raw material gas for a downstream fluidized-bed reactor and introducing the polymer powder to the downstream fluidized-bed reactor in a multi-stage gas-phase polymerization method. SOLUTION: A multi-stage gas-phase polymerization method in which polymerization is conducted in upstream and downstream fluidized-bed reactors connected in series so that a polymer powder which is obtained from a raw material gas mixture comprising at least ethylene gas, an α-olefin and hydrogen gas in the fluidized-bed reactor placed upstream is extracted and introduced to the fluidized-bed reactor placed downstream, wherein an extraction step to extract the polymer powder from the upstream fludized-bed reactor, a treatment step to reduce the contents of the α-olefin gas and hydrogen gas in the extracted polymer powder and an introduction step to introduce the treated polymer powder to the downstream fluidized-bed reactor are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multistage gas-phase polymerization method using at least two fluidized-bed reactors in succession by extracting polymer powder obtained in a fluidized-bed reactor disposed upstream. And a method for reducing the amount of subcomponents mixed in the polymer powder when the polymer powder is introduced into a fluidized bed reactor provided on the downstream side.

[0002] The present invention also relates to an apparatus for reducing the amount of entrained subcomponents of polymer powder for applying the above method, and a multistage gas phase polymerization apparatus using the apparatus.

[0003]

2. Description of the Related Art Conventionally, for example, when an ethylene / α-olefin copolymer or the like is obtained, ethylene and α-olefin
A gas-phase polymerization method in which a mixture of olefins is subjected to gas-phase polymerization in a fluidized-bed reactor in the presence of a titanium-based solid catalyst is used.

[0004] By the way, when a single fluidized bed reactor is used for producing a polymer, the physical properties of the obtained polymer are limited to a certain range. Will be. Therefore, as the needs of the market are diversified, products having more complicated physical properties are desired, and a method of connecting a plurality of fluidized-bed reactors to produce polymers having different properties is used. The molecular weight, purity,
Polymers having various physical properties with different physical properties were obtained.

[0005] Such a method includes a multi-stage gas phase polymerization method, for example, as shown in FIG.
Recently, a two-stage gas-phase polymerization apparatus in which the second fluidized-bed reactor 11 and the second fluidized-bed reactor 121 are continuously connected has been widely used.

That is, the first fluidized bed reactor 111 is supplied with a solid catalyst A from a supply line 115 and a raw material gas mixture comprising, for example, ethylene and α-olefin from a supply line 112 through a blower 113.
Through the bottom of the first fluidized-bed reactor 111.

The raw material gas mixture is preliminarily mixed with hydrogen gas as a reaction terminator so that the polymerization reaction does not proceed excessively. By appropriately stopping the polymerization reaction with this hydrogen gas, the molecular weight of the polymer obtained in the first fluidized bed reactor 111, which is the first-stage polymerization apparatus, can be suppressed.

[0008] The supplied gaseous olefin passes through a dispersion plate 117 such as a perforated plate disposed near the bottom of the first fluidized bed reactor 111 to form a fluidized bed 118. 118 is maintained in a fluid state. At this time, a polymerization reaction is performed in the fluidized bed 118.

[0009] Then, the produced polymer particles are continuously extracted, and the rotary valve 1 of the extraction line 130 is extracted.
It is discharged to the transport line 125 by 35 and sent to the second fluidized bed reactor 121 through the transport line.

[0010] The unreacted raw material gas that has passed through the fluidized bed 118 has its flow velocity reduced in a deceleration region 119 provided above the first fluidized bed reactor 111, so that the first fluidized bed reacts. The gas is discharged to the outside of the first fluidized-bed reactor 111 via a gas outlet provided at an upper portion of the reactor 111.

The unreacted raw material gas discharged from the first fluidized bed reactor 111 passes through a circulation line 116, is cooled by a heat exchanger (cooling device) 114, and is supplied to a supply line 1
12 and is continuously supplied again into the fluidized bed 118 in the first fluidized-bed reactor 111 by the blower 113.

On the other hand, in the second fluidized-bed reactor 121, the polymer powder extracted from the first fluidized-bed reactor 111 through an extraction line 130 is transferred from the first fluidized-bed reactor 111 to a transport line. The raw material gas mixture is supplied from the supply line 122 via the blower 123 while being sent through the supply line 125. In this manner, in the second fluidized bed reactor 121, the fluidized bed 128 is formed together with the polymer powder, the olefin gas, and the solid catalyst contained in the polymer powder so that the polymerization reaction is performed. It has become. Then, the copolymer obtained in the second fluidized bed reactor 121 is continuously extracted from the line 126.

The transfer line 125 is branched from the supply line 122, and the other end is connected to the second fluidized bed reactor 1
21, the gas containing olefin sent from the supply line 122 is supplied to the centrifugal blower 141.
While the pressure is increased by a pressure increasing means such as the above, the polymer powder extracted from the first fluidized bed reactor 111 is conveyed along with this gas and introduced into the second fluidized bed reactor 121. I have.

In the above, a two-stage fluidized-bed reactor, that is, a configuration in which a first fluidized-bed reactor 111 and a second fluidized-bed reactor 121 are continuously connected is shown. It has also been practiced to connect multiple stages of fluidized bed reactors continuously.

[0015]

By the way, in such a multistage gas-phase polymerization method, in order to impart a plurality of physical properties to the obtained polymer, an upstream fluidized bed reactor, for example,
The polymerization is carried out with a desired raw material gas mixture composition in a fluidized bed reactor 111, and the obtained polymer powder is withdrawn via a withdrawal line 130, and the polymer powder is withdrawn to a downstream fluidized bed reactor, for example, a second fluidized bed reactor. It is subjected to polymerization in a fluidized bed reactor 121.

Here, the second fluidized bed reactor 121 is usually used.
Then, the polymerization is carried out by using a raw material gas mixture having a different composition while changing the contents of the α-olefin gas and the hydrogen gas from the upstream side.

However, in such a method, desired physical properties can be imparted to the polymer in the first-stage polymerization reaction, but the desired physical properties can be obtained more upstream in the polymerization reaction on the further downstream side. Could not be applied to the resulting polymer.

The present inventors have conducted intensive studies on the investigation of the cause, and as a result, when introducing the polymer powder from the upstream side to the downstream side, α-olefin and hydrogen gas (subcomponent) introduced together with the polymer powder It has been found that by reducing the amount of, the composition of the raw material gas mixture to be supplied to the downstream side can be adjusted to impart desired physical properties to the downstream side, and the present invention has been completed.

The present invention has been made in view of the above situation, and in a multistage gas phase polymerization method, polymer powder extracted from an upstream fluidized bed reactor is caused to accompany raw material gas of a downstream fluidized bed reactor. When transported and introduced into the downstream fluidized bed reactor, the polymer powder inhibits the polymerization reaction in the downstream fluidized bed reactor or makes it difficult to control the physical properties of the target polymer. It is an object of the present invention to provide a multistage gas phase polymerization method for performing polymerization by removing hydrogen gas and comonomer.

Further, in the present invention, in a multistage gas phase polymerization apparatus, before introducing polymer powder extracted from the fluidized bed reactor on the upstream side into the fluidized bed reactor on the downstream side, hydrogen gas is introduced from the powder. It is an object of the present invention to provide an apparatus for reducing the content of subcomponents by removing subcomponents such as water and comonomer, and a multistage gas phase polymerization apparatus to which the device is applied.

[0021]

DISCLOSURE OF THE INVENTION The present invention has been made to achieve the objects and objects of the prior art as described above.
A polymer powder obtained by a polymerization reaction using a raw material gas mixture consisting of at least ethylene gas, α-olefin gas and hydrogen gas in a fluidized bed reactor disposed on the upstream side is extracted, and a fluidized flow disposed on the downstream side In a multi-stage gas phase polymerization method in which polymerization is carried out by continuously connecting so as to be introduced into a bed reactor, an extraction step of extracting polymer powder from the upstream fluidized bed reactor, A treatment step of reducing the content ratio of the α-olefin gas and the hydrogen gas in the combined powder, and an introduction step of introducing the treated polymer powder into the downstream fluidized bed reactor. And

As described above, in the multistage gas-phase polymerization, the polymerization was carried out using a raw material gas mixture comprising at least ethylene gas, α-olefin gas and hydrogen gas in the upstream fluidized bed reactor. The polymer powder is withdrawn, the content ratio of unreacted α-olefin gas and hydrogen gas in the powder is reduced, and then the powder is introduced into a downstream fluidized bed reactor to obtain a fluidized fluid in each stage. It is possible to adjust the composition of the raw gas mixture actually reacted for each bed reactor. This makes it possible to change the physical properties imparted to the polymer at each stage according to the use of the polymer obtained.

In the multistage gas-phase polymerization method according to the present invention, the treatment step comprises introducing a gas stream of a predetermined gas into the polymer powder extracted from the fluidized bed reactor on the upstream side, and mixing α and α in the powder. -It is preferable that the step be a step of removing olefin gas and hydrogen gas.

As described above, by removing auxiliary components such as α-olefin gas and hydrogen gas mixed in the polymer obtained on the upstream side before sending it to the fluidized bed reactor on the downstream side, the polymer is removed. The subcomponent content of the powder can be effectively reduced.

In the multistage gas-phase polymerization apparatus of the present invention, at least in the first stage, the solid catalyst for polymerization is supplied into the fluidized bed reactor, and in each stage, the raw material gas mixture is supplied from the bottom of the fluidized bed reactor via a dispersion plate. Into a fluidized-bed reactor to form a fluidized bed in the fluidized-bed reactor, and a multistage fluidized-bed reactor for producing a polymer by a gas-phase polymerization reaction in the fluidized-bed reactor. A feed path for introducing the raw material gas mixture into the disposed fluidized bed reactor, a feed path connected above the downstream fluidized bed reactor, and one end connected to the feed path, and the other end upstream A line connected to a fluidized bed reactor disposed on the side, and the raw material gas mixture is composed of at least ethylene gas, α-olefin gas and hydrogen gas, and in the transport path, the upstream fluidized bed reactor The polymerization obtained in The powder is extracted, and after the treatment for reducing the content ratio of the α-olefin gas and the hydrogen gas (hereinafter, also referred to as “subcomponent”) in the extracted polymer powder is performed, the polymer powder after the treatment is processed. Is introduced into the downstream fluidized bed reactor.

As described above, in the multistage gas-phase polymerization, the polymerization was carried out using a raw material gas mixture comprising at least ethylene gas, α-olefin gas and hydrogen gas in the upstream fluidized bed reactor. The polymer powder is withdrawn, the content ratio of unreacted α-olefin gas and hydrogen gas in the powder is reduced, and then the powder is introduced into a downstream fluidized bed reactor to obtain a fluidized fluid in each stage. It is possible to adjust the composition of the raw gas mixture actually reacted for each bed reactor. This makes it possible to change the physical properties imparted to the polymer at each stage according to the use of the polymer obtained.

Further, in the multistage gas phase polymerization apparatus of the present invention, the line is provided with a separation means for removing α-olefin gas and hydrogen gas mixed in the polymer powder from the polymer powder. And

Further, the separating means includes a stagnation tank for temporarily retaining the polymer powder, an introduction path for introducing a gas stream of a predetermined gas into the stagnation tank, and discharge of the subcomponent. It is preferable that an exhaust path is provided for removing the auxiliary component mixed in the polymer powder retained in the retention tank from the discharge path using an airflow introduced from the introduction path.

As described above, for example, the separation means provided with the retention tank, the introduction path, and the discharge path is provided, and the polymer powder obtained on the upstream side is temporarily retained in the retention tank, and a predetermined amount of the polymer powder is introduced from the introduction path here. By introducing and purging the gas flow,
Subcomponents can be effectively separated from the polymer powder and extracted from the discharge path. This makes it possible to effectively reduce the content of subcomponents in the polymer powder provided on the downstream side.

The apparatus for reducing the entrainment of subcomponents of polymer powder in the multistage gas-phase polymerization apparatus of the present invention comprises supplying a solid catalyst for polymerization into a fluidized bed reactor at least in the first stage, and a fluidized bed in each stage. A raw material gas mixture comprising at least ethylene gas, α-olefin gas and hydrogen gas is blown into the fluidized bed reactor from the bottom of the reactor via a dispersion plate to form a fluidized bed in the fluidized bed reactor. A multi-stage fluidized-bed reactor for producing a polymer by a gas-phase polymerization reaction in a bed, and a branch from an introduction path for introducing a raw material gas mixture into a fluidized-bed reactor disposed on the downstream side, A conveying path connected above the fluidized bed reactor, and a line connected at one end to the conveying path and connected at the other end to a fluidized bed reactor disposed on the upstream side; Polymerization obtained in a vessel In a multistage gas phase polymerization apparatus in which powder is withdrawn through the line and continuously connected so as to be introduced into the fluidized bed reactor on the downstream side to carry out polymerization, the weight introduced into the downstream side A device for reducing the entrainment amount of subcomponents of the coalesced powder, a retention tank for temporarily retaining the polymer powder, and an introduction path for introducing a gas flow of a predetermined gas into the retention tank, A discharge path for discharging the sub-components, and using an airflow introduced from the introduction path, the α-olefin gas and the hydrogen gas (sub-component) mixed in the polymer powder retained in the retention tank. It is characterized by being pulled out.

As described above, in the multistage gas phase polymerization apparatus, the polymer powder obtained on the upstream side is temporarily retained in the retention tank, and a gas stream of a predetermined gas is introduced from the introduction path and purged, thereby achieving the above-described method. Subcomponents can be effectively separated from the polymer powder and extracted from the discharge passage. This allows
It is possible to effectively reduce the content of subcomponents in the polymer powder provided on the downstream side.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multistage gas phase polymerization method and a multistage gas phase polymerization apparatus according to the present invention and an apparatus for reducing the entrainment of subcomponents of polymer powder in the multistage gas phase polymerization apparatus will be described below with reference to the drawings. I will explain it.

FIG. 1 is a schematic view showing one embodiment of a multistage gas phase polymerization apparatus according to the present invention. As shown in FIG. 1, this multi-stage gas phase polymerization apparatus performs a polymerization reaction using a raw material gas mixture containing at least ethylene and α-olefin in the presence of a solid catalyst such as a metallocene catalyst and a titanium-based catalyst. A first fluidized bed reactor 1 for obtaining an ethylene / α-olefin copolymer powder (hereinafter simply referred to as “polymer powder”), and a product discharge line 3 from the first fluidized bed reactor 1
In the first fluidized-bed reactor 1 for carrying out a polymerization reaction using the polymer powder taken out through the polymer powder 0, the solid catalyst entrained in the powder, and the raw material gas mixture newly supplied, And a second fluidized bed reactor 11 connected thereto.

Here, the raw material gas mixture is a gas mixture containing at least ethylene, α-olefin, and hydrogen (hereinafter, components other than ethylene may be collectively referred to as “subcomponents”). Further, the mixing ratio of each gas is different between the raw material gas mixture G1 supplied in the first fluidized bed reactor 1 and the raw material gas mixture G2 supplied in the second fluidized bed reactor 11. The α-olefin has 3 to 20 carbon atoms, preferably 4 to 13 carbon atoms.
And more preferably an α-olefin having 4 to 12 carbon atoms, especially butene, hexene, 4-methyl-1-pentene and the like.

As a specific embodiment, for example, when metallocene is used and hexene is used as a monomer, the mixing ratio of the α-olefin is changed to the raw gas mixture G1.
Is about 10 mol%, preferably 3 to 8 mol%, and about 5 mol%, preferably 1 to 3 mol% in the raw material gas mixture G2. Also, the raw material gas mixture G
1, The composition of G2 may be changed and used. That is, in the raw material gas mixture G1, it is about 5 mol%, preferably 1 to 3 mol%, and in the raw material gas mixture G2, it is about 10 mol%, preferably 3 to 8 mol%.

Further, the raw material gas mixture may be mixed with an inert gas such as nitrogen, a saturated hydrocarbon, for example, isopentane. When such a gas is mixed with the raw material gas mixture, it becomes easy to remove heat generated in the polymerization process.

In the first fluidized-bed reactor 1, a solid catalyst A for polymerization is fed into the first fluidized-bed reactor 1 from a catalyst supply line 5.
Is supplied, and the raw material gas mixture G1 is blown from the raw material supply line 2 to the bottom of the first fluidized bed reactor 1 by the blower 3, and the raw material gas mixture G1 is sent above the dispersion plate 7. Above the dispersion plate 7, a fluidized bed 8 is formed by the raw material gas mixture G1 and the solid catalyst A. The fluidized bed (reaction system) 8 is maintained in a fluidized state while the fluidized bed 8 is maintained in a fluidized state. The first stage gas phase polymerization reaction is carried out to obtain copolymer particles or powder.

On the other hand, the unreacted raw material gas mixture that has passed through the fluidized bed 8 has its flow velocity reduced in a deceleration region 9 provided above the first fluidized bed reactor 1, and
The fluid is discharged to the outside of the first fluidized bed reactor 1 via a gas outlet provided at the upper part of the fluidized bed reactor 1.

The raw material gas mixture discharged from the first fluidized bed reactor 1 merges with the raw material supply line 2 via the circulation line 6 and is again supplied into the fluidized bed 8. ing. In addition, since the heat of the polymerization reaction needs to be removed before being supplied again into the fluidized bed 8, the heat exchanger 4 is provided on the circulation line 6 and cooled by passing through the heat exchanger 4. It merges with the raw material supply line 2.

On the other hand, as in the first fluidized bed reactor 1, the second fluidized bed reactor 11 supplies the raw material gas mixture G2 having a mixing ratio different from that of the raw material gas mixture G1 to the raw material supply line 1.
2 is blown into the bottom of the second fluidized bed reactor 11 by the blower 13 so that the raw material gas mixture G2 is sent above the dispersion plate 17. Above the dispersion plate 17, the fluidized bed 18 is formed by using the fed raw material gas mixture G2, the polymer powder introduced from the transport line 15, and the solid catalyst for polymerization accompanying the polymer powder. Is formed, and a copolymer is obtained by a further gas phase polymerization reaction in the fluidized bed 18 while maintaining the fluidized bed 18 in a fluidized state.

The transfer line 15 branches off from the supply line 12 at the outlet side of the blower 13 and is connected to the outlet side of the powder extracting line 30 on the way.
Above the fluidized bed reactor 11, for example, in the gas region above the fluidized bed.

On the other hand, the unreacted raw material gas mixture that has passed through the fluidized bed 18 has its flow velocity reduced in a deceleration region 19 provided above the second fluidized bed reactor 11,
The gas is discharged to the outside of the second fluidized bed reactor 11 through a gas outlet provided at the upper part of the second fluidized bed reactor 11. Also, the discharged raw gas mixture is
Since it is necessary to remove the heat of the polymerization reaction before it is supplied again into the fluidized bed 18, a heat exchanger 14 is provided on the circulation line 16 and cooled by passing through the heat exchanger 14, It merges with the supply line 12.

The copolymer produced by the progress of the polymerization reaction in the fluidized bed 18 is taken out from a product discharge line 40. The second fluidized bed reactor 1
In 1 as well, a solid catalyst may be added. By the way, the polymer powder produced by the progress of the polymerization reaction in the fluidized bed 8 is:
The product discharge line 30 is connected to the first fluidized bed reactor 1 at one end.
And the other end is connected to the transport line 15, respectively.
Here, a main valve 24, a separator 31 and a valve 25 are arranged in this order from the first fluidized bed reactor 1 side.

Then, the polymer powder from the first fluidized-bed reactor 1 sent to the product discharge line 30 is separated by a separating device 31.
In the above, secondary components such as α-olefin (comonomer) and hydrogen gas mixed in the polymer powder are separated and extracted. The main valve 24 is a weight valve,
When a certain amount of polymer powder is generated in the first fluidized bed reactor 1, it is sent to the separation device 31. On the other hand, for example, the valve 25 is configured such that only the powder component obtained by the separation device 31 by the operation of the rotary valve is
A fixed amount is discharged to the transport line 15. Then, the powder portion of the polymer is subjected to the second flow by the flow of the raw material gas mixture from the blower 13 as a transport medium.
To the fluidized bed reactor 11.

As shown in FIG. 2, the separation device 31 includes a purge bin 33 as a retention tank for temporarily retaining the polymer powder sent through the main valve 24, and a purge bin 33. A purge gas supply line 32 as an introduction path for introducing a predetermined gas, that is, a purge gas, and a polymer remaining in a purge bin 33 using a purge gas introduced from the purge gas supply line 32 via a purge gas valve 34. It is configured such that subcomponents mixed in the powder are separated and extracted from a purge gas discharge line 35 as a discharge path.

In the separation device 31, the first fluidized bed reactor 1
The polymer powder obtained in the above is temporarily retained in the purge bin 33, the purge gas valve 34 is opened, a purge gas is fed from the purge gas supply line 32, and the purge gas is caused to collide with the polymer powder so that the subcomponent is polymerized. In addition to separating from the powder, the auxiliary components separated from the purge gas discharge line 35 are effectively discharged and removed from the purge gas discharge line 35 by being put on the flow of the purge gas.

Examples of the purge gas include ethylene and the above-mentioned inert gas. Further, the purged comonomer (α-olefin) and hydrogen gas may be combined with the circulation line 6 through, for example, a not-shown line and supplied to the fluidized bed 8 again, or may be directly supplied to the first bed.
May be returned to the fluidized bed reactor 1 or may be separately collected and used for other purposes.

As described above, according to the present invention, the polymer powder produced in the first fluidized bed reactor 1 is extracted and the content ratio of the α-olefin gas and the hydrogen gas in the extracted polymer powder is determined. After the α-olefin gas and the hydrogen gas mixed in the polymer powder are extracted from the polymer powder in the separation device 31 as a suitable means for performing a treatment for lowering the
The polymer powder after this treatment is introduced into the second fluidized bed reactor 11.

Thus, the α-olefin gas and the hydrogen gas which have not been reacted in the polymerization reaction of the first fluidized bed reactor 1 are effectively removed before being introduced into the second fluidized bed reactor 11. Therefore, unreacted secondary components in the first fluidized bed reactor 1 do not affect the polymerization reaction in the second fluidized bed reactor 11.

Therefore, for example, the content ratio of the minor components (α-olefin gas and hydrogen gas) of the raw material gas mixture in the downstream fluidized bed reactor is compared with that of the raw material gas mixture in the upstream fluidized bed reactor. In the case of a smaller size, polymerization is performed such that the upstream fluidized bed reactor has a relatively small molecular weight and a large α-olefin content, while the downstream fluidized bed reactor has a larger molecular weight than the upstream side. The polymerization can be carried out such that the α-olefin content becomes small.

When the content ratio of the subcomponent of the raw material gas mixture in the downstream fluidized bed reactor is made larger than that of the raw material gas mixture in the upstream fluidized bed reactor, the upstream flow In a bed reactor, polymerization is performed such that the molecular weight is relatively large and the α-olefin content is small, while in a downstream fluidized bed reactor, the molecular weight is small and the α-olefin content is large compared to the upstream side. Polymerisation can be carried out.

Thus, it is easy to impart desired physical properties to the polymer powder through each stage of the polymerization reaction by simply changing the component ratio of the raw material gas mixture to be supplied to each stage of the polymerization reaction, thereby diversifying. It becomes possible to produce polymers that meet the needs of the market.

In the above embodiment, the two-stage polymerization method has been described. However, it is needless to say that the present invention can be applied to a multi-stage gas-phase polymerization of three or more stages.

Further, in the above-described embodiment, the example in which the separation device is provided in one stage is shown. However, in order to more surely separate the subcomponents, the purge bins are provided in a higher number of stages, for example, two or three stages. Is also good.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the object of the present invention.

[0056]

According to the multistage gas phase polymerization method of the present invention, it is possible to adjust the composition of the raw material gas mixture actually reacted in each fluidized bed reactor in each stage. This makes it possible to change the physical properties imparted to the polymer at each stage according to the use of the obtained polymer.

Further, auxiliary components such as α-olefin gas and hydrogen gas mixed in the polymer obtained on the upstream side are separated using a predetermined gas stream before being sent to the downstream fluidized bed reactor. By extracting, the content of subcomponents in the polymer powder can be effectively reduced, so that the introduction of subcomponents into the downstream fluidized bed reactor can be easily suppressed.
Therefore, the control of the polymerization reaction in each stage becomes easy, and the physical properties imparted to the polymer in each stage can be effectively changed.

According to the multistage gas phase polymerization apparatus of the present invention, it is possible to adjust the composition of the raw material gas mixture actually reacted in each stage of the fluidized bed reactor. This makes it possible to change the physical properties imparted to the polymer at each stage according to the use of the obtained polymer.

Further, for example, a separation means having a retention tank, an introduction path and a discharge path is provided, and the polymer powder obtained on the upstream side is temporarily retained in the retention tank, and a predetermined gas is supplied from the introduction path to the polymer powder. By introducing an air stream and purging, the sub-components can be effectively separated from the polymer powder and extracted from the discharge path. This makes it possible to effectively reduce the content of subcomponents in the polymer powder supplied to the downstream side, so that the polymerization reaction on the downstream side can be effectively controlled. Therefore, the physical properties imparted to the polymer can be effectively changed at each stage.

According to the apparatus for reducing the entrainment of subcomponents of polymer powder in the multistage gas phase polymerization apparatus of the present invention, the polymer powder obtained on the upstream side in the multistage gas phase polymerization apparatus is temporarily retained in a retention tank. Then, by introducing a gas stream of a predetermined gas from the introduction path and purging it, the subcomponent can be effectively separated from the polymer powder and extracted from the discharge path. This makes it possible to effectively reduce the content of subcomponents in the polymer powder provided on the downstream side.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of a multistage gas phase polymerization apparatus according to the present invention.

FIG. 2 is a schematic view showing one embodiment of an apparatus for reducing the entrainment amount of subcomponents of a polymer powder in a multistage gas phase polymerization apparatus according to the present invention.

FIG. 3 is a schematic diagram showing a conventional multistage gas phase polymerization apparatus.

[Explanation of symbols]

 Reference Signs List 1 first fluidized bed reactor 2 raw material supply line 3 blower 4 heat exchanger 5 catalyst supply line 6 circulation line 7 dispersion plate 8 fluidized bed 9 deceleration region 11 second fluidized bed reactor 12 raw material supply line 13 blower 14 heat Exchanger 15 Conveying line 16 Circulation line 17 Dispersion plate 18 Fluidized bed 19 Deceleration area 24 Main valve 25 Valve (rotary valve) 30 Product discharge line 31 Separator 32 Purge gas supply line 33 Purge bin 34 Valve 35 Purge gas discharge line 40 Product discharge line

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiaki Kikuchi 3 Chizusa Kaigan, Ichihara-shi, Chiba Mitsui Chemicals Co., Ltd. Engineering Co., Ltd.

Claims (6)

[Claims] 1. A polymer powder obtained by a polymerization reaction using a raw material gas mixture comprising at least ethylene gas, α-olefin gas and hydrogen gas in a fluidized bed reactor disposed on the upstream side, and withdrawing the polymer powder on the downstream side In a multistage gas phase polymerization method in which polymerization is performed by continuous connection so as to be introduced into a fluidized bed reactor disposed in the step, an extraction step of extracting a polymer powder from the upstream fluidized bed reactor And a treatment step of reducing the content ratio of α-olefin gas and hydrogen gas in the extracted polymer powder, and an introduction step of introducing the treated polymer powder into the downstream fluidized bed reactor. A multi-stage gas-phase polymerization method comprising: 2. The processing step comprises a step of introducing a gas stream of a predetermined gas into the polymer powder extracted from the fluidized bed reactor on the upstream side to extract α-olefin gas and hydrogen gas mixed in the powder. The multi-stage gas phase polymerization method according to claim 1, wherein 3. At least in the first stage, the polymerization solid catalyst is supplied into the fluidized bed reactor, and in each stage, the raw material gas mixture is blown into the fluidized bed reactor from the bottom of the fluidized bed reactor via a dispersion plate. A fluidized-bed reactor is formed in a fluidized-bed reactor, a multistage fluidized-bed reactor for producing a polymer by a gas-phase polymerization reaction in the fluidized-bed reactor, and a fluidized-bed reactor disposed downstream. A conveying path branched from an introduction path for introducing the raw material gas mixture and connected above the fluidized bed reactor on the downstream side; and a fluidized bed reaction having one end connected to the conveying path and the other end arranged on the upstream side. A raw material gas mixture comprising at least ethylene gas, α-olefin gas and hydrogen gas, and the polymer powder obtained in the upstream fluidized bed reactor in the transport path. Is extracted and extracted After the treatment to reduce the content ratio of α-olefin gas and hydrogen gas (hereinafter, also referred to as “subcomponent”) in the treated polymer powder, the treated polymer powder is subjected to the fluidized bed reaction on the downstream side. A multi-stage gas-phase polymerization apparatus which is introduced into a vessel. 4. The multistage gas generator according to claim 3, wherein a separation means for removing α-olefin gas and hydrogen gas mixed in the polymer powder from the polymer powder is provided in the line. Phase polymerization equipment. 5. A separation tank for temporarily storing the polymer powder, an introduction path for introducing a gas stream of a predetermined gas into the storage tank, and discharging the subcomponent. And a discharge path for removing the auxiliary component mixed in the polymer powder retained in the retention tank from the discharge path using an airflow introduced from the introduction path. 2. The multi-stage gas phase polymerization apparatus according to item 1. 6. At least in the first stage, a solid catalyst for polymerization is supplied into a fluidized-bed reactor, and in each stage, at least ethylene gas, α-olefin gas and hydrogen gas are supplied from the bottom of the fluidized-bed reactor via a dispersion plate. A plurality of stages of fluidized-bed reactors for producing a polymer by a gas-phase polymerization reaction in the fluidized-bed reactor by blowing a raw material gas mixture comprising A transfer path branched from an introduction path for introducing the raw material gas mixture into the fluidized bed reactor disposed on the downstream side and connected above the downstream fluidized bed reactor, and one end connected to the transfer path. A line connected to a fluidized bed reactor, the other end of which is disposed on the upstream side, and the polymer powder obtained in the fluidized bed reactor on the upstream side is withdrawn through the line, Introduce into fluidized bed reactor In a multi-stage gas phase polymerization apparatus in which the polymerization is performed by continuously connecting the polymer powders, a device for reducing the entrainment amount of the secondary component of the polymer powder introduced into the downstream side, wherein the polymer powder is temporarily A stagnation tank for stagnation, an introduction path for introducing an airflow of a predetermined gas into the stagnation tank, and a discharge path for discharging the sub-components. Wherein α-olefin gas and hydrogen gas (subcomponent) mixed in the polymer powder retained in the retention tank are extracted from the discharge passage. Equipment that reduces the amount of component entrainment.