JP2006052387A - Continuous polymerization apparatus for olefin, method for transferring polymer granule and method for polymerizing olefin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous polymerization apparatus for olefins in which a reactive gas accompanying polymer granules pulled out from an upstream vapor phase polymerization tank can readily be substituted in an arbitrary ratio with other gas and transferred to a downstream vapor phase polymerization tank and continuous vapor phase polymerization of olefin is advantageously practiced thereby, in continuous polymerization for olefins using the apparatus in which a plurality of vapor phase polymerization tanks are serially arranged. <P>SOLUTION: The continuous polymerization apparatus for olefins uses a plurality of vapor phase polymerization tanks having a specific structure (see the figure) serially arranged. The figure exhibits one example of the relationship between a gas substitution tank and the vapor phase polymerization tank arranged in the upstream of the gas substitution tank. A fluidized bed is arranged in the interior of the upstream polymerization tank 1 and the gas substitution tank 2 is connected through a first transfer pipe 4 composed of a pulling-up nozzle 4a and connecting piping 4b to the lower part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an olefin continuous polymerization apparatus in which a plurality of gas phase polymerization tanks are arranged in series, and after the reaction gas accompanying the polymer particles produced in the upstream polymerization tank is replaced with another gas, the polymer powder The present invention relates to a continuous polymerization apparatus capable of intermittently or continuously transferring particles to a downstream polymerization tank, and a method for transferring polymer particles and an olefin polymerization method using the apparatus.

  Inside the fluidized bed gas phase polymerization tank of olefin, a fluidized bed is formed in which the polymer particles flow by the reaction gas. If this polymer granular material is extracted from the polymerization tank, the coexisting reaction gas is necessarily accompanied. The reaction gas is mainly composed of a raw material olefin gas, but additionally contains a secondary raw material gas necessary for causing a desired polymerization reaction in the polymerization tank. In some cases, this auxiliary material gas may be inconvenient for later processes. For example, in a multistage polymerization apparatus having a plurality of polymerization tanks, when hydrogen as a molecular weight regulator is used as a secondary raw material gas, if more hydrogen than the amount required for the subsequent reaction is contained in the entrained gas from the previous stage, In the subsequent polymerization, it becomes difficult to produce a polymer having a desired molecular weight, and the range of the polymer composition that can be produced is limited. In order to solve such a problem, conventionally, a method of separating as much as possible the auxiliary raw material gas accompanying the polymer particles extracted from the polymerization tank has been devised.

  For example, in Patent Document 1, a method in which two polymer sedimentation tanks are provided in parallel after the gas phase polymerization tank and are alternately transferred to the next process, and two polymer sedimentation tanks are provided in series after the gas phase polymerization tank. A method is disclosed in which a polymer is separated in a first tank and transferred to a second tank, and then the separated polymer is transferred to the next step. Patent Document 2 discloses a method of increasing the diameter of the polymer receiving pipe in the first tank in order to improve the separability of the polymer in the first tank when two tanks are provided in series. Yes. Patent Document 3 discloses a method in which a pressure equalizing line is provided in a settling tank, and the precipitated polymer particles are intermittently discharged together with the particles and a small amount of gas to the next step. Patent Document 4 discloses a method of defining the extraction conduit from the gas phase polymerization tank at a constant angle in the downward direction. However, these methods require two polymer sedimentation tanks, making it difficult to operate continuously or changing the gas replacement rate arbitrarily.

US Pat. No. 4,621,952 JP 2000-53707 A JP-A-3-153708 U.S. Pat. No. 5,928,612

  The present invention is an olefin continuous polymerization apparatus in which a plurality of gas phase polymerization tanks are arranged in series, and the gas accompanying the polymer particles extracted from the upstream gas phase polymerization tank can be easily and arbitrarily added. A device that can be replaced with another gas (eg, fresh olefin gas) in a proportion, and the gas entrained in the polymer particles from the upstream gas phase polymerization tank can be replaced easily and at any replacement rate Another object of the present invention is to provide a method for transferring polymer particles to a downstream gas phase polymerization tank and a continuous olefin polymerization method using the method.

The present invention, in one aspect thereof, is a continuous polymerization apparatus for olefins,
The device
A plurality of gas phase polymerization tanks arranged in series (the plurality of polymerization tanks include a combination of an upstream polymerization tank and a downstream polymerization tank that are adjacent to each other via one gas replacement tank, (It is arranged upstream of the downstream polymerization tank, and the gas replacement tank is connected to the upstream polymerization tank by a first transfer pipe and to the downstream polymerization tank by a second transfer pipe) Have
The gas replacement tank has a gas dispersion plate disposed therein (the gas dispersion tank is partitioned into an upper region and a lower region by the gas dispersion plate),
The upper region is
Inlet (this is the opening of the first transfer pipe, and the polymer particles produced in the upstream polymerization tank are accompanied by the first gas from the upstream polymerization tank and pass through the gas replacement tank. Transferred to)
Gas replacement chamber (here, the polymer particles transferred from the upstream polymerization tank are temporarily stored and introduced from the upstream polymerization tank along with the polymer particles into the polymer particles. At least a portion of the first gas present is replaced by a second gas supplied to the gas replacement tank; and an outlet (which is an opening in the second transfer tube, and the polymer (Powder is discharged from the gas replacement chamber toward the downstream polymerization tank)
Have
The lower region relates to a device characterized by having a gas inlet for introducing the second gas.

The present invention, in a second aspect, is a continuous olefin polymerization method in which an olefin is polymerized in the presence of a catalyst in each gas phase polymerization tank in a continuous polymerization apparatus having a plurality of gas phase polymerization tanks arranged in series. The continuous polymerization apparatus is an apparatus according to the first aspect of the present invention, and relates to a method having the following steps.
The polymer particles produced in the upstream polymerization tank are introduced into the gas replacement chamber of the gas replacement tank through the first transfer pipe together with at least a part of the first gas in the upstream polymerization tank. Process;
A second gas is supplied from the gas inlet into the lower region, and is further introduced into the gas replacement chamber through the gas dispersion plate, whereby the polymer particles in the polymer powder in the gas replacement chamber are introduced. Replacing at least a portion of one gas with the second gas; and intermittently passing the polymer powder together with the gas present therein from the gas replacement chamber through the second transfer pipe. The process of transferring to a downstream polymerization tank.

In a third aspect, the present invention relates to a continuous polymerization apparatus having a plurality of gas phase polymerization tanks arranged in series, more typically of a polymer granule which is performed in a continuous polymerization process of olefins using the apparatus. It is a transfer method, The said continuous polymerization apparatus is an apparatus which concerns on the 1st side surface of this invention, It concerns on the method characterized by having the following processes.
The polymer particles produced in the upstream polymerization tank are introduced into the gas replacement chamber of the gas replacement tank through the first transfer pipe together with at least a part of the first gas in the upstream polymerization tank. Process;
A second gas is supplied from the gas inlet into the lower region, and is further introduced into the gas replacement chamber through the gas dispersion plate, whereby the polymer particles in the polymer powder in the gas replacement chamber are introduced. Replacing at least a portion of one gas with the second gas; and intermittently passing the polymer powder together with the gas present therein from the gas replacement chamber through the second transfer pipe. The process of transferring to a downstream polymerization tank.

  According to the present invention, in the continuous polymerization of olefins using an apparatus in which a plurality of gas phase polymerization tanks are arranged in series, the gas accompanying the polymer particles extracted from the upstream gas phase polymerization tank can be easily and It can be replaced with another gas (typically fresh olefin gas) in any proportion and transferred to a downstream gas phase polymerization vessel, which advantageously allows continuous gas phase polymerization of olefins to be carried out. it can.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a relationship between a gas replacement tank and a gas phase polymerization tank disposed upstream thereof in the apparatus according to the present invention. A gas dispersion plate 1a is arranged inside the upstream polymerization tank 1, and a gas replacement tank 2 is connected to the lower part via a first transfer pipe 4 comprising an extraction nozzle 4a and a connection pipe 4b. The gas replacement tank and the downstream polymerization tank 3 installed downstream thereof are connected via a second transfer pipe 5. In this example, a transfer control valve 5a is provided in the second transfer pipe. The gas replacement tank typically has an upper wall, a vertical side wall, and a bottom wall, and the inside thereof is partitioned into an upper region 21 and a lower region 22 by a gas dispersion plate 2d. The upper area of the gas replacement tank is
Inlet 2a (this is the opening of the first transfer pipe 4, and the polymer particles produced in the upstream polymerization tank 1 are accompanied by a first gas from the upstream polymerization tank and pass through the first gas. Transferred to the gas replacement tank 2);
Gas replacement chamber 2b (Here, the polymer particles transferred from the upstream polymerization tank 1 are temporarily stored and introduced from the upstream polymerization tank along with the polymer particles to the polymer powder particles. At least a portion of the first gas present therein is replaced by a second gas supplied to the gas replacement tank 2; and an outlet 2c (which is an opening of the second transfer pipe 5). And the polymer powder is discharged from the gas replacement chamber 2b toward the downstream polymerization tank 3).
have.

  A gas blowing port 2 e for introducing the second gas is provided in the lower region 22 of the gas replacement tank 2. The second gas (typically olefin gas) introduced into the lower region from the gas inlet through the supply line 10 is blown into the gas replacement chamber 2b through the gas dispersion plate 2d. The polymer powder discharged from the upstream polymerization tank 1 to the first transfer pipe 4 enters the gas replacement tank accompanied by the first gas from the upstream polymerization tank, and temporarily enters the gas replacement chamber. Stored. The first gas entrained in the polymer particles and present in the polymer particles is replaced by the second gas blown through the gas dispersion plate in the gas replacement chamber. After the gas replacement is performed for a predetermined time, the polymer particles are transferred to the downstream polymerization tank 3 through the second transfer pipe 5 having the transfer control valve 5a.

  Auxiliary raw materials such as a catalyst, olefin, and hydrogen are charged into the upstream polymerization tank 1 from the catalyst supply line 6, the olefin supply line 7, and the auxiliary raw material supply line 8, respectively, where the olefin is polymerized into polymer particles. The polymer particles are fluidized in the polymerization tank by the circulating gas introduced from the circulating gas line 9. The polymer particles produced in the upstream polymerization tank are extracted into the gas replacement tank 2 through the first transfer pipe 4. The first gas (gas mixed with the olefin and the auxiliary material) entrained in the polymer powder is replaced by the second gas (typically olefin gas) blown through the gas dispersion plate 2d, and the first gas Is fed back to the upstream polymerization tank 1 through the transfer pipe 4.

  In the gas replacement chamber 2b of the gas replacement tank 2, the second gas introduced from the gas inlet 2e and dispersed by the gas dispersion plate 2d flows into the polymer powder from the upstream polymerization tank 1 and flows into the polymer powder. The first gas present in the voids in the body layer is replaced. Regardless of the amount of the second gas to be injected, the second gas is introduced into the polymer powder by providing a gas dispersion plate having a structure capable of uniformly blowing the gas supplied from the back side from the entire front side. Can be contacted uniformly and efficiently. As the gas dispersion plate, a plate having a porous structure such as a multi-through-hole plate or a sintered metal plate is typically used. However, the differential pressure characteristic for uniform gas dispersion in the radial direction of the gas replacement tank is used. A material having a structure in which the powder does not fall through the gas dispersion plate is preferably used.

  The second gas introduced into the gas replacement tank 2 from the gas inlet 2e is typically a fresh olefin gas, but the amount introduced is the total amount of raw material consumed by the reaction in the upstream polymerization tank 1 It is desirable to be within the range. Depending on the polymerization conditions, it is necessary to purge the reaction gas. In this case, the purged gas is discarded or recovered. The amount of gas entrained in the polymer powder extracted from the gas replacement tank is the pressure difference between the gas replacement tank 2 and the downstream polymerization tank 3, the diameter and length of the second transfer pipe 5, and the type of polymer powder and gas. However, it is possible to arbitrarily control the replacement rate of the accompanying gas by adjusting the ratio of the second gas amount to be introduced to the accompanying gas amount. By arbitrarily controlling the replacement rate of the entrained gas, it is possible to control necessary physical properties such as the molecular weight of the polymer to be produced, and at the same time, it is possible to prevent the loss of the purged reaction gas.

  The polymer particles subjected to gas replacement are opened and closed by opening and closing a transfer control valve 5a provided in the second transfer pipe 5 from the lower part of the gas replacement chamber 2b of the gas replacement tank 2 to the attached downstream polymerization tank 3. And the downstream polymerization tank are directly extracted into the downstream polymerization tank using a pressure difference between them. The powder surface of the polymer granular material layer in the gas replacement tank is lowered by the extraction, and the polymer granular material continuously flows from the upstream polymerization tank 1 into the gas replacement tank due to gravity drop.

In FIG. 2, the relationship of the 1st transfer pipe 4 which connects the upstream polymerization tank 1, the gas replacement tank 2, and both in an example of the superposition | polymerization apparatus of this invention is shown. In this example, the upstream polymerization tank has a vertical side wall 1b in which the first transfer pipe is open. In FIG. 2, S ₁ is an angle of an angle formed by a slope line 4c of the inner bottom portion of the first transfer pipe with a horizontal line at the lower end 1c of the joint portion between the first transfer pipe and the vertical side wall of the upstream polymerization tank ( °). At the point 1c, when the inner bottom portion of the first transfer pipe extends straight from the vertical side wall of the upstream polymerization tank, the gradient line of the inner bottom portion of the first transfer pipe is the first transfer pipe. It is the straight line formed by the inner bottom part. On the other hand, when the inner bottom portion of the first transfer pipe extends in a curved line from the vertical side wall of the upstream polymerization tank at the point 1c, the gradient line of the inner bottom portion of the first transfer pipe is the first It is the tangent at the point 1c of the curve formed by the inner bottom of the transfer tube. S ₂ is the longitudinal side walls of the first transfer tube the upstream polymerization reactor and the first transfer pipe a tangent 4d of the inner bottom surface of the first transfer tube in bent or curved to have portions downwardly Is the angle (°) of the angle formed by the line passing through the joint upper end 1d with the horizontal line. d indicates the inner diameter of the first transfer pipe 4. In order to smoothly flow polymer particles into the gas replacement tank from the upstream polymerization tank via the first transfer pipe only by gravity drop regardless of the pressure difference, S ₁ and S ₂ are as follows: What is necessary is just to determine so that Formula (1) and (2) may be satisfied.
0 ° ≦ S ₁ ≦ 90 ° (1)
Ar ≦ S ₂ ≦ 90 ° (2)
Here, Ar is the angle of repose (°) of the polymer particles produced in the upstream polymerization tank. The angle of repose of the polymer granular material in the present invention is described in F. on pages 85 to 88 of “Reinhold Chemical Engineering Series” (published by Reinhold, New York (1960)). A. Zenz, D.M. F. It refers to the angle of repose defined in “Fluidization and Fluid-Particle Systems” co-authored by Othmer.

Preferable S ₂ is the gradient at the joint between the first transfer pipe 4 and the vertical side wall 1b of the upstream polymerization tank 1, the position where the inner bottom of the first transfer pipe is bent or curved downward, and the bent or curved shape. Even if the angle is fixed, it varies depending on the size of the inner diameter d of the first transfer pipe. However, if d is determined according to S ₁ and S ₂ that satisfy the above formulas (1) and (2), the polymer particles can be flowed satisfactorily. In the case of S ₁ = 0, it means that the first transfer pipe protrudes horizontally with respect to the vertical side wall of the upstream polymerization tank, but even in this case, S ₂ satisfies the expression (2). If the inner diameter d of the first transfer pipe and the position where the inner bottom portion of the first transfer pipe bends or curves downward are determined, the polymer particles can be smoothly introduced by gravity drop.

  The capacity of the gas replacement chamber 2b of the gas replacement tank 2 is determined by the apparent volume of the polymer powder (that is, the polymer powder volume of the polymer powder transferred by the intermittent single transfer of the polymer powder to the downstream polymerization tank 3). The total volume of the actual volume and the volume of the gas present in the polymer powder is preferably not less than. When the polymer particles are intermittently transferred from the gas replacement tank, the amount of the first gas remaining in the polymer particles can be suppressed by taking a sufficiently large volume of the gas replacement chamber 2b. . In the gas replacement chamber, the polymer particles and the second gas are in continuous contact, but the distance between the opening 2a of the first transfer pipe and the opening 2c of the second transfer pipe in the gas replacement tank is short. If the contact time between the polymer particles and the second gas is too short, the first gas flows directly into the second transfer pipe 5 or the first gas in the polymer particles. The replacement with the second gas becomes insufficient, and the amount of the first gas flowing into the downstream polymerization tank 3 increases. By setting the volume of the gas replacement chamber 2b to be equal to or greater than the amount of the polymer powder extracted to the second transfer pipe 5 by one intermittent transfer operation of the polymer powder from the gas replacement tank 2, the above-mentioned desirable No phenomenon can be prevented.

  The gas dispersion plate 2d installed in the gas replacement tank 2 is preferably selected to have a pressure loss due to the gas dispersion plate of 0.2 kPa or more during operation of the apparatus. By appropriately selecting the gas dispersion plate, even when a small amount of the second gas is supplied, the second gas can be uniformly dispersed over the entire cross section of the gas replacement tank.

  In the first aspect, the present invention provides a continuous polymerization apparatus for olefins as described above. In the second aspect, the present invention provides a continuous polymerization process for olefins using the continuous polymerization apparatus, Moreover, in the 3rd side surface, the transfer method of the polymer granular material from an upstream polymerization tank to a downstream polymerization tank performed in the continuous polymerization process of such an olefin is provided.

The method for continuously polymerizing olefins according to the second aspect of the present invention is an olefin for polymerizing olefins in the presence of a catalyst in each gas phase polymerization tank in a continuous polymerization apparatus having a plurality of gas phase polymerization tanks arranged in series. In the continuous polymerization method, the continuous polymerization apparatus is the apparatus described in detail above, and has the following steps.
The polymer particles produced in the upstream polymerization tank are introduced into the gas replacement chamber of the gas replacement tank through the first transfer pipe together with at least a part of the first gas in the upstream polymerization tank. Process;
A second gas is supplied from the gas inlet into the lower region, and is further introduced into the gas replacement chamber through the gas dispersion plate, whereby the polymer particles in the polymer powder in the gas replacement chamber are introduced. Replacing at least a portion of one gas with the second gas; and intermittently passing the polymer powder together with the gas present therein from the gas replacement chamber through the second transfer pipe. The process of transferring to a downstream polymerization tank.

The method for transferring polymer particles according to the third aspect of the present invention is a method for transferring polymer particles performed in a continuous polymerization process of olefins in a continuous polymerization apparatus having a plurality of gas phase polymerization tanks arranged in series. And the said continuous polymerization apparatus is an apparatus demonstrated in detail above, It is a method characterized by having the following processes.
The polymer particles produced in the upstream polymerization tank are introduced into the gas replacement chamber of the gas replacement tank through the first transfer pipe together with at least a part of the first gas in the upstream polymerization tank. Process;
A second gas is supplied from the gas inlet into the lower region, and is further introduced into the gas replacement chamber through the gas dispersion plate, whereby the polymer particles in the polymer powder in the gas replacement chamber are introduced. Replacing at least a portion of one gas with the second gas; and intermittently passing the polymer powder together with the gas present therein from the gas replacement chamber through the second transfer pipe. The process of transferring to a downstream polymerization tank.

  The ratio of the weight per unit time of the second gas introduced from the gas inlet 2e to the weight per unit time of the polymer particles transferred from the gas replacement tank 2 to the downstream polymerization tank 3 is adjusted. By doing so, it is easy to control the substitution rate of the first gas in the polymer granular material by the second gas. By controlling the substitution rate of the first gas with the second gas in the polymer granular material, the concentration of the auxiliary material in the gas in the downstream polymerization tank is adjusted, and a useful polymer according to the purpose. Can be obtained.

  The polymerization pressure in the upstream polymerization tank 1 is preferably maintained at a pressure higher by 0.2 MPa to 1.0 MPa than the polymerization pressure in the downstream polymerization tank 3. In the present invention, the polymer granular material together with the gas mainly composed of the second gas (typically olefin gas) supplied to the gas replacement tank 2 is subjected to a pressure difference between the gas replacement tank and the downstream polymerization tank. The transfer is performed by pneumatic transportation, which is determined by the pressure difference, the transfer pipe size, the properties of the polymer and gas to be handled, and the like. The pressure difference between the upstream polymerization tank and the downstream polymerization tank is preferably as large as possible from the viewpoint of easy transfer of polymer particles, but if too large, the difference in polymerization conditions between these two polymerization tanks becomes too large. The polymerization pressure in the polymerization tank is preferably maintained at a pressure higher by 0.2 MPa to 1.0 MPa than the polymerization pressure in the downstream polymerization tank. The apparent volume of the polymer particles to be transferred by the intermittent single transfer of the polymer particles to the downstream polymerization tank 3 (that is, the actual volume of the polymer particles and the gas present in the polymer particles). The total volume) is preferably less than the capacity of the gas replacement chamber 2b of the gas replacement tank 2. Moreover, it is preferable to supply the second gas to the gas replacement tank at such a speed that the pressure loss due to the gas dispersion plate 2d is 0.2 kPa or more. Furthermore, it is effective to ensure a sufficient contact time with the second gas at the time of stopping the polymer granular material transfer in the interval of the intermittent transfer operation.

The present invention provides a technique related to continuous polymerization of olefin, and the olefin applicable to the present invention is not particularly limited as long as it is an olefin that can be polymerized by the action of a catalyst, but preferably C _{2 to} C ₁₀ , particularly preferably C _{2 to} C ₈ olefins such as ethylene, propylene, or ethylene and one or more C _{3 to} C ₁₀ , particularly preferably C _{3 to} C ₈ olefins such as propylene, 1-butene, 1-hexene, 4 -Methyl-1-pentene, 1-octene) and the like are used. In each polymerization tank, gas phase polymerization is performed in the presence of an appropriately selected olefin polymerization catalyst in the presence of a secondary material such as a molecular weight regulator such as hydrogen gas or an inert gas such as nitrogen as necessary. Examples of the catalyst include various metallocene catalysts and Ziegler-Natta catalysts. The polymerization conditions such as the polymerization pressure, the polymerization time, the polymerization temperature, and the types and amounts of the auxiliary materials may be appropriately set based on common knowledge of those skilled in the art. In addition, in the continuous polymerization apparatus having one or more additional gas phase polymerization tanks other than the upstream polymerization tank and the downstream polymerization tank sandwiching the gas replacement tank described in detail above, the structure of the additional gas phase polymerization tank is as described above. Although the structure is basically the same as the structure of the upstream polymerization tank, the specifications such as the capacity, the number of raw material supply lines, and the stirring mode can be selected as appropriate.

  Next, the present invention will be described by examples. As will be described in more detail, the present invention is not limited to these examples.

Example 1
Polymer powder particles were intermittently transferred in an apparatus in which an upstream polymerization tank, a gas replacement tank, and a downstream polymerization tank were arranged in series in this order, and the transfer state of the polymer particles and the gas replacement state were examined.
The gas replacement tank had a cylindrical shape with an inner diameter of 250 mm and a height of 1000 mm, and the inside thereof had a structure separated into two chambers by a gas dispersion plate having a pressure loss of 0.25 KPa in the operating state. Below the gas dispersion plate is a substitution gas inlet, above the gas dispersion plate is an inlet (with an inner diameter of 8 inches) for receiving the polymer particles from the upstream polymerization tank, and from the gas substitution tank to the downstream polymerization tank All outlets (1 inch inner diameter) were provided, and the volume from the gas dispersion plate to the inlet was about 25L.
An upstream polymerization tank and a downstream polymerization tank of the same type with an internal volume of 1.2 m ³ are arranged in series, and an extraction nozzle with an opening having an inner diameter of 8 inches extending horizontally from the vertical side wall of the upstream polymerization tank, followed by a horizontal of 8 inches with an inner diameter. The gas replacement tank was connected with a simple connection pipe. The total pipe length of the extraction nozzle and the connection pipe was 250 mm. The angles between the upstream polymerization tank and the piping were S ₁ = 0 ° and S ₂ = 39 °.
The gas replacement tank and the downstream polymerization tank were connected by a transfer pipe equipped with a transfer control valve.
The inside of the upstream polymerization tank was maintained at 1.0 MPaG with a temperature of 70 ° C. and a ratio of mole of hydrogen to ethylene (hereinafter referred to as H ₂ / C ′ ₂ ratio) = 1/10. In the upstream polymerization tank, polymer particles having an average particle diameter of 1050 μm, a bulk specific gravity of 0.37 g / cc, and an angle of repose of 35 ° were sufficiently fluidized by a gas flow having a linear velocity of 0.22 m / sec. . In the downstream polymerization tank, the flow state was maintained with nitrogen gas at a temperature of 70 ° C. and a pressure of 0.2 MPaG. Next, while supplying fresh ethylene at a rate of 40 kg / h from the gas inlet of the gas replacement tank, the polymer particles were intermittently transferred from the upstream polymerization tank to the downstream gas phase polymerization tank via the gas replacement tank. As for the transfer conditions of the polymer particles from the gas replacement tank, the opening time of the transfer control valve was 3 sec, and the transfer interval was 30 sec. The amount of polymer powder particles transferred per intermittent transfer was 4.4 kg. As a result of analyzing the gas in the downstream polymerization tank, the H ₂ / C ′ ₂ ratio was 0.15 / 10, and it was found that the replacement in the gas replacement tank was sufficiently performed. Moreover, the outflow situation of the polymer particles to the gas replacement tank was also good. The experimental conditions and the results of gas analysis of the downstream polymerization tank are shown in Table 1.
In this example, S ₁ = 0 °, S ₂ = 39 °, Ar = 35 °, and both the following conditions (1) and (2) were satisfied.

0 ° ≦ S ₁ ≦ 90 ° (1)
Ar ≦ S ₂ ≦ 90 ° (2)

Examples 2-6
Experiments were performed in the same manner as in Example 1 except that the conditions were changed as shown in Table 1. The experimental conditions and results are shown in Table 1.

Comparative Example 1
As a result of transferring the polymer particles under the same conditions as in Example 1 except that ethylene was not introduced from the gas blowing port of the gas replacement tank, the transfer amount per opening of the transfer control valve was 5.0 kg. It was. As a result of analysis of the gas in the downstream polymerization tank, the H ₂ / C ′ ₂ ratio was 1/10, and the composition of the gas accompanying the polymer particles was the same as that in the upstream polymerization tank. In addition, the outflow situation to the gas substitution tank of the polymer particles was good.

It is a figure which shows an example of the relationship between the gas substitution tank and upstream polymerization tank in the continuous polymerization apparatus which concerns on this invention. It is a figure which shows the relationship of the 1st transfer pipe which connects the upstream superposition | polymerization tank, gas replacement tank, and both in an example of the continuous polymerization apparatus of this invention.

Explanation of symbols

1: Upstream polymerization tank 1a: Gas dispersion plate 1b: Longitudinal side wall 1c: Lower end of the junction of the first transfer pipe and the vertical side wall of the upstream polymerization tank 1d: Joining of the first transfer pipe and the vertical side wall of the upstream polymerization tank Upper end of part 2: Gas replacement tank 21: Upper region 22: Lower region 2a: Inlet 2b: Gas replacement chamber 2c: Outlet 2d: Gas dispersion plate 2e: Gas blowing port 3: Downstream polymerization tank 4: First transfer pipe 4a: Extraction nozzle 4b: Connection pipe 5: Second transfer pipe 5a: Transfer control valve 6: Catalyst supply line 7: Olefin gas supply line 8: Secondary raw material supply line 9: Circulating gas line 10: Second gas supply line S ₁ : Angle at which the inner bottom of the first transfer pipe forms a horizontal line at the lower end of the joint between the first transfer pipe and the vertical side wall of the upstream polymerization tank S2: The first transfer pipe bends or curves downward The inner bottom surface of the first transfer pipe Angle d corners line passing through the joint upper ends of the vertical side wall of the transfer tube and the upstream polymerization reactor of the first A in forms with a horizontal line: the inside diameter of the first transfer pipe

Claims (9)

An olefin continuous polymerization apparatus comprising:
The device
A plurality of gas phase polymerization tanks arranged in series (the plurality of polymerization tanks include a combination of an upstream polymerization tank and a downstream polymerization tank that are adjacent to each other via one gas replacement tank, (It is arranged upstream of the downstream polymerization tank, and the gas replacement tank is connected to the upstream polymerization tank by a first transfer pipe and to the downstream polymerization tank by a second transfer pipe) Have
The gas replacement tank has a gas dispersion plate disposed therein (the gas dispersion tank is partitioned into an upper region and a lower region by the gas dispersion plate),
The upper region is
Inlet (this is the opening of the first transfer pipe, and the polymer particles produced in the upstream polymerization tank are accompanied by the first gas from the upstream polymerization tank and pass through the gas replacement tank. Transferred to)
Gas replacement chamber (here, the polymer particles transferred from the upstream polymerization tank are temporarily stored and introduced from the upstream polymerization tank along with the polymer particles into the polymer particles. At least a portion of the first gas present is replaced by a second gas supplied to the gas replacement tank; and an outlet (which is an opening in the second transfer tube, and the polymer (Powder is discharged from the gas replacement chamber toward the downstream polymerization tank)
Have
The lower region has a gas inlet for introducing the second gas. The upstream polymerization tank has a vertical side wall in which the first transfer pipe is open,
The apparatus according to claim 1, wherein an inner bottom portion of the first transfer pipe extends from a vertical side wall of the upstream polymerization tank in a horizontal or downward direction. The first transfer pipe has an inner bottom bent or curved downward in the middle,
The apparatus according to claim 2, wherein the following expressions (1) and (2) are satisfied.
0 ° ≦ S ₁ ≦ 90 ° (1)
Ar ≦ S ₂ ≦ 90 ° (2)
In the formula (1), S ₁ is an angle (°) formed by the inner bottom portion of the first transfer pipe and a horizontal line at the lower end of the joint portion between the first transfer pipe and the vertical side wall of the upstream polymerization tank. S ₂ is a tangent to the inner bottom surface of the first transfer pipe at a portion where the first transfer pipe is bent or curved downward, and is a vertical line between the first transfer pipe and the upstream polymerization tank. The angle (°) formed by the line passing through the upper end of the joint with the side wall and the horizontal line is Ar (°), and Ar is the angle of repose (°) of the polymer particles produced in the upstream polymerization tank. A method for transferring polymer particles in a continuous polymerization apparatus having a plurality of gas phase polymerization tanks arranged in series, wherein the continuous polymerization apparatus is the apparatus according to claim 1, and the following steps are performed. A method characterized by comprising:
The polymer particles produced in the upstream polymerization tank are introduced into the gas replacement chamber of the gas replacement tank through the first transfer pipe together with at least a part of the first gas in the upstream polymerization tank. Process;
A second gas is supplied from the gas inlet into the lower region, and is further introduced into the gas replacement chamber through the gas dispersion plate, whereby the polymer particles in the polymer powder in the gas replacement chamber are introduced. Replacing at least a portion of one gas with the second gas; and the polymer particles together with the gas present therein intermittently from the gas replacement chamber and through the second transfer pipe. The process of transferring to a downstream polymerization tank. An olefin continuous polymerization method for polymerizing an olefin in the presence of a catalyst in each gas phase polymerization tank in a continuous polymerization apparatus having a plurality of gas phase polymerization tanks arranged in series, wherein the continuous polymerization apparatus comprises: A method according to claim 1, comprising the following steps:
The polymer particles produced in the upstream polymerization tank are introduced into the gas replacement chamber of the gas replacement tank through the first transfer pipe together with at least a part of the first gas in the upstream polymerization tank. Process;
A second gas is supplied from the gas inlet into the lower region, and is further introduced into the gas replacement chamber through the gas dispersion plate, whereby the polymer particles in the polymer powder in the gas replacement chamber are introduced. Replacing at least a portion of one gas with the second gas; and the polymer particles together with the gas present therein intermittently from the gas replacement chamber and through the second transfer pipe. The process of transferring to a downstream polymerization tank. Adjusting the ratio of the weight per unit time of the second gas introduced from the gas inlet to the weight per unit time of the polymer particles transferred from the gas replacement tank to the downstream polymerization tank; The method according to claim 5, wherein the substitution rate of the first gas in the polymer granular material by the second gas is controlled. The method according to claim 5, wherein the polymerization pressure in the upstream polymerization tank is maintained at a pressure higher by 0.2 MPa to 1.0 MPa than the polymerization pressure in the downstream polymerization tank. The apparent volume of the polymer particles transferred per intermittent transfer from the gas replacement tank to the downstream polymerization tank is not more than the volume of the gas replacement chamber of the gas replacement tank, The method according to claim 5. The method according to claim 5, wherein the second gas is supplied under a condition that a pressure loss in the gas dispersion plate is 0.2 kPa or more.

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