JP2000273104A - Method for extracting powder in powder preparing apparatus and method for extracting powder in gas phase polymerization reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable powder to be extracted without clogging in a purge bin or valves by placing a purge bin downstream from a powder preparing apparatus and by placing a plurality of flow regulating valves downstream from the purge bin and by regulating each flow regulating valve to extract powder stepwise. SOLUTION: After the operation of a gas phase polymerization reactor, polyolefin powder is produced in fluidized bed reactor 1 and the powder is discharged to a extraction line 30. A change in the amount of the powder in fluidized bed reactor 1 is detected by a level indicator 45 and inputted regulator 46. The divergences of flow regulating valve 24 and 25 are controlled based on the command signal from a regulator 46, which regulates the discharge from a purge bin 22. This prevents the powder from accumulating in large quantities for a long time in the purge bin and enables the powder to constantly move to thereby prevent the progress of polymerization and aggregation of the powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for extracting powder in a powder production apparatus and a method for extracting powder in a gas phase polymerization reactor.

[0002]

2. Description of the Related Art Conventionally, for obtaining a polyolefin such as polyethylene, a gas phase polymerization method in which an olefin monomer or the like is subjected to gas phase polymerization in a fluidized bed reactor in the presence of a titanium-based solid catalyst has been used. Have been.

[0003] As such a method today, for example,
As shown in FIG. 4, a gas-phase polymerization apparatus using a fluidized-bed reactor 111 has been widely used. That is, the solid catalyst A is supplied from the supply line 115 to the fluidized bed reactor 111, and the gaseous olefin is supplied from the bottom of the fluidized bed reactor 111 via the blower 113 from the supply line 112. It has become.
The supplied gaseous olefin is supplied to the fluidized bed reactor 1
Dispersion plate 1 made of a perforated plate or the like disposed near the bottom of 11
17 to form a fluidized bed 118,
8 is maintained in a fluid state. At this time, a polymerization reaction is performed in the fluidized bed 118. Then, the produced polymer particles are continuously discharged to the withdrawal line 130, stored in the purge bin 132, and retained for a predetermined time.
4 so as to be continuously extracted.

[0004]

In such a gas-phase polymerization reactor, the polymer powder extracted from the fluidized-bed reactor 111 via the extraction line 130 is:
Since the temperature is close to the polymerization temperature, the lump generated in the fluidized bed reactor 111 or the polymerization reaction proceeds while staying in the extraction line 130 and the purge bin 132, and the lump generated in the purge bin 132 Alternatively, clogging may occur in the valve 134.

Therefore, the operation is temporarily stopped, and the valve 134 is stopped.
Alternatively, the purge bin 132 and the like must be disassembled and cleaned, which requires complicated work and a cleaning device, and reduces the operation efficiency of the device itself.

In view of the above situation, the present invention provides a method of extracting powder in a powder manufacturing apparatus capable of extracting powder produced by a powder manufacturing apparatus without clogging in a purge bin or a valve. It is an object of the present invention to provide a method for extracting powder in a gas phase polymerization vessel.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned objects and objects of the prior art, and a method for extracting powder in a powder manufacturing apparatus according to the present invention is described below. A purge bin is arranged below the powder manufacturing apparatus, a plurality of flow control valves are arranged downstream of the purge bin, and the respective flow control valves are controlled so that the powder manufactured by the powder manufacturing apparatus can be used. It is featured to be taken out gradually.

[0008] With this configuration, the mass of the powder due to the agglomeration generated in the fluidized bed reactor and the agglomeration generated by the agglomeration of the powder in the purge bin due to its own weight or the progress of the polymerization reaction. Clogging can be prevented.

Further, the method for extracting powder in a gas phase polymerization reactor according to the present invention is characterized in that a solid catalyst for polymerization is supplied into a fluidized bed reactor, and a single amount of catalyst is supplied from the bottom of the fluidized bed reactor through a dispersion plate. In a method of extracting powder in a gas phase polymerization reactor for blowing a body gas into a fluidized bed reactor to form a fluidized bed in the fluidized bed reactor and producing a polymer by a gas phase polymerization reaction in the fluidized bed. A purge bin is provided in the middle of a powder extraction line for extracting polymer powder from the fluidized-bed reactor, and a plurality of flow control valves are disposed downstream of the purge bin. It is characterized by being gradually extracted.

Thus, the powder of the polymer or the like can be extracted without clogging. Further, in the method for extracting powder in a gas phase polymerization reactor according to the present invention, two purge bins are provided in the powder extraction line, a flow control valve corresponding to an upstream purge bin is set as a first flow control valve, and When the flow control valve corresponding to the purge bin is a second flow control valve, and when the first flow control valve is fully opened, the opening degree of the second flow control valve is changed to the powder of the fluidized bed reactor. When the second flow control valve is fully opened, the opening degree of the first flow control valve is controlled based on the detection result of the powder of the fluidized bed reactor. The control is based on the detection result of the level meter for detecting the level.

By adjusting the opening of the flow control valve, the powder can be effectively extracted without clogging.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method of extracting a powder in a powder production apparatus according to the present invention will be described with reference to the drawings, taking a case where a polymer is produced by a gas phase polymerization apparatus as an example.

In the present invention, the term "polymerization" is sometimes used to mean not only homopolymerization but also copolymerization, and the term "polymer" means not only homopolymer but also homopolymer. , May also be used in a meaning including a copolymer.

As shown in FIG. 1, the apparatus for producing polyolefin comprises a fluidized bed reactor 1 for polymerizing olefins using a catalyst to obtain polyolefin powder, and a line for extracting powder from the fluidized bed reactor 1. And a powder extracting device for extracting the polyolefin powder through the same.

In the fluidized bed reactor 1, a solid catalyst A for polymerization is supplied from a line 5 into the fluidized bed reactor 1, and gaseous monomers are supplied from a supply line 2 by a blower 3 to the fluidized bed reactor 1. And the gaseous monomer is sent above the dispersion plate 7. Above the dispersion plate 7, a fluidized bed 8 is formed by the fed gaseous monomer 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 in 8 to obtain polymer or copolymer particles or powder.

Here, the gaseous monomer is one or more monomers (monomer, comonomer), for example, an olefin gas, which is polymerized by the action of a solid catalyst for polymerization. It may be supplied with a molecular weight controller, an inert gas such as nitrogen or hydrocarbons.

On the other hand, the unreacted gaseous monomer 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 Via a gas outlet provided at the top of the fluidized bed reactor 1 of
The first fluidized-bed reactor 1 is discharged to the outside.

The fluidized bed reactor 1 according to the present embodiment
A level meter 45 for detecting the amount of generated powder is installed in the inside, and the detection result detected by the level meter 45 is output to the controller 46. Then, based on a command signal from the controller 46, the opening degree of the first flow control valve 24 and the second flow control valve 25 provided in the powder extraction line 30 described later is controlled.

The powder extraction line 30 includes:
The above-described first flow control valve 24 and second flow control valve 25
, A purge bin 22 may be provided. In the present embodiment, the powder is gradually extracted by appropriately controlling the two flow control valves 24 and 25.

Hereinafter, a method of extracting powder according to the present invention applied to the two-stage gas phase polymerization reactor will be described. When the polyolefin powder is generated in the first fluidized-bed reactor 1 after the gas-phase polymerization reactor is driven and operated, the powder is discharged to the extraction line 30 as described above. At this time, a change in the amount of powder in the fluidized bed reactor 1 is detected by the level meter 45, and the detection result is output to the controller 46. In addition,
At this time, the opening degree of the first flow control valve 24 and the second flow control valve 25 is controlled based on the command signal from the controller 46, and the discharge amount from the purge bin 22 is appropriately adjusted.

As described above, in this embodiment, the purge bin 2
Since the flow control valves 24 and 25 are provided downstream of 2, the powder does not stay in the purge bin in a large amount and stays for a long time and is constantly moving, so that polymerization does not proceed. Therefore, clogging of the powder is prevented. In the above embodiment, a one-stage polymerization method has been described. However, it is needless to say that the present invention can be applied to two or more-stage multistage gas-phase polymerization.

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. For example, various valves can be used as the flow control valve. Further, in the above embodiment, the level meter 45 is provided in the fluidized bed reactor in the powder manufacturing apparatus, and the opening of the flow control valve 25 is adjusted based on the result of the level meter 45. The adjustment of the adjusting valve may be controlled by a timer or the like, and other methods can be adopted. Further, the present invention is not limited to polyolefin powder, and can be applied to extraction of other powder.

In the above embodiment, the purge bin 22 is provided downstream of the fluidized bed reactor 1, but the number of purge bins is not limited to one, and two purge bins may be provided. FIG. 2 shows an example in which two purge bins are provided downstream of the fluidized bed reactor 1. 1 denote the same elements as those in the above-described embodiment, and a detailed description thereof will be omitted.

As shown in FIG. 2, the apparatus for producing a polyolefin has a fluidized bed reactor 1. Fluidized bed 8
The polyolefin powder produced by the progress of the polymerization reaction therein is sent to a powder extraction line 30 provided with two purge bins 21 and 22. From the fluidized bed reactor 1 side, the main valve 23, the first
, A first flow regulating valve 24, a second purge bin 22, and a second flow regulating valve 25 are arranged in this order. In the fluidized bed reactor 1 according to the present embodiment,
A level meter 45 for detecting the amount of generated powder is provided. The detection result from the level meter 45 is output to the controller 46. The openings of the first flow control valve 24 and the second flow control valve 25 are controlled based on the command signal from the controller 46.

The method for extracting powder according to the present embodiment will be described below with reference to FIG. After the operation of the gas phase polymerization reactor, in the initial state, the main valve 23 is opened and the first flow control valve 24 is closed. Further, the second flow control valve 25 is open. Therefore,
The inside of the second purge bin 22 is empty. When polyolefin powder is generated in the first fluidized bed reactor 1 from this state, the powder passes through the main valve 23 and is separated into solid and gas in the first purge bin 21, and gradually into the first purge bin 21. It accumulates (step 1).

When the powder is stored in the first purge bin 21 by a predetermined amount, that is, by a predetermined weight, the first flow rate control valve 24 is opened by the weight, and the second flow rate from the first purge bin 21 to the second A solid component containing a polyolefin powder and a solid catalyst (hereinafter referred to as a “solid component”)
(Step 2).

At this time, the amount of powder in the fluidized bed reactor 1 is detected by the level meter 45 and output to the controller 46. Based on this command signal, the opening of the first flow control valve 24 is controlled. You. At this time, the flow control valve 25 is fully opened.

As described above, when a certain amount of solid component flows down from the first purge bin 21 to the second purge bin 22, the first purge bin 2 is continuously discharged from the fluidized bed reactor 1.
Since the polyolefin powder flows down into the first purge bin 21, the powder increases again in the first purge bin 21. Also, the second
The polyolefin powder is discharged from the purge bin 22 through the second flow control valve 25. After a lapse of a predetermined time, the first flow control valve 24 is fully opened, and at the same time, a change in the amount of powder in the reactor 1 is detected by the level meter 45 in the fluidized bed reactor 1 and output to the controller 46. Is done. In this step 3, the opening of the second flow control valve 25 is controlled based on the command signal from the controller 46, and the discharge amount from the second purge bin 22 is appropriately adjusted.

When the amount of powder in the second purge bin 22 increases to near the state of being full, the first flow control valve 24 is connected to the control signal of the controller 46, the discharge amount is adjusted, and at the same time, the second flow control valve 24 is controlled. The flow control valve 25 is fully opened, the powder in the second purge bin 22 is completely discharged, and becomes empty. (Step 4).

As described above, in the present embodiment, since a plurality of purge bins 21 and 22 are provided and the flow control valves 24 and 25 corresponding to these are provided, a large amount of powder is contained in one purge bin. In addition, since it does not stay for a long time, polymerization does not proceed. Therefore, clogging of the powder is prevented.

As described above, in the present invention, the number of purge bins is not limited to one. In the case of a multistage gas phase polymerization reactor, the location of the flow control valve is not limited, and it may be located on any extraction line.

[0032]

According to the present invention, since powder is dispersed and extracted in a plurality of purge bins, clogging of the powder in the valve or the purge bin can be prevented. Further, if the present invention is applied to a gas phase polymerization vessel, powder generated before the polymerization reaction proceeds can be transferred to another purge bin, so that clogging of the powder can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a multi-stage gas phase polymerization vessel to which a powder extraction method according to the present invention is applied.

FIG. 2 is a schematic diagram showing a multi-stage gas phase heavy machine according to another embodiment to which the powder extracting method according to the present invention is applied.

FIG. 3 is a graph illustrating an example of a method for detecting clogging of a powder extraction line in the multistage gas phase polymerization reactor shown in FIG.

FIG. 4 is a schematic view showing a gas phase polymerization vessel to which a conventional powder extraction method is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st fluidized bed reactor 7 Dispersion plate 8 Fluidized bed 17 Dispersion plate 18 Fluidized bed 21 1st purge bin 22 2nd purge bin 23 Main valve 24 1st flow control valve 25 2nd flow control valve

Continuing on the front page (72) Inventor Satoru Oya 3 Chigusa Coast, Ichihara-shi, Chiba Mitsui Chemicals Co., Ltd. (72) Inventor Tomohiro Arase 3 Chigusa Coast, Ichihara-shi, Chiba Mitsui Chemicals F Term (reference) 4G068 AA07 AB22 AC09 AE02 AF01 AF36 4J011 AA01 DB16 DB27 DB30

Claims (3)

[Claims] 1. A purge bin is disposed below a powder manufacturing apparatus, and a plurality of flow control valves are disposed downstream of the purge bin. A method for extracting powder in a powder manufacturing apparatus, wherein the powder is gradually extracted. 2. A solid catalyst for polymerization is supplied into the fluidized-bed reactor, and monomer gas is blown into the fluidized-bed reactor from the bottom of the fluidized-bed reactor via a dispersion plate, thereby obtaining a fluidized-bed reaction. A powder extraction method in a gas phase polymerization reactor for forming a fluidized bed in a vessel and producing a polymer by a gas phase polymerization reaction in the fluidized bed, wherein a powder extraction line for extracting a polymer powder from the fluidized bed reactor A purge bin is disposed in the middle of the process, a plurality of flow control valves are disposed downstream of the purge bin, and powder is gradually extracted through these flow control valves. Powder extraction method in 3. A method according to claim 1, wherein two purge bins are provided in the powder extraction line, a flow control valve corresponding to an upstream purge bin is a first flow control valve, and a flow control valve corresponding to a downstream purge bin is a second flow control valve. When the first flow control valve is fully opened, the opening degree of the second flow control valve is determined based on the detection result of the level meter for detecting the level of the powder in the fluidized bed reactor. When the second flow control valve is fully open, the opening of the first flow control valve is determined based on the detection result of a level meter that detects the level of powder in the fluidized bed reactor. 3. The method according to claim 2, wherein the method is controlled.