JPH06229400A - Method for supplying catalyst - Google Patents

Abstract

PURPOSE:To supply catalyst slurry into a reactor stably without blocking of any catalyst supplying pipe by providing a specific catalyst supplying device, and maintaining inner pressure of the catalyst tank in a higher level than that of the reaction tank. CONSTITUTION:When catalyst slurry 7 formed by suspending solid catalyst in inert solvent is supplied from a catalyst reserving tank 6 into a reactor 3, a catalyst supplying device 1 provided with a rotor having the flow passage 10 of the catalyst slurry 7 is arranged between the catalyst reserving tank 6 and the reactor 3. The inner pressure of the catalyst reserving tank 6 is maintained higher than inner pressure of the reactor 3, and the rotor is rotated so as to connect/disconnect the catalyst reserving tank 6 to/from the reactor 3 aternately. The inner pressure of the catalyst reserving tank 6 is maintained higher than that of the reactor 3 by 0.1 to 4kg/cm<2>. It is possible to regulate the supply amount of the catalyst slurry 7 by maintaining the differential that pressure between both tanks with in a specific range.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for supplying a catalyst. More specifically, the present invention relates to improvement of a method for supplying a catalyst slurry in which a solid catalyst is suspended in an inert solvent from a catalyst storage tank to a reaction tank.

[0002]

2. Description of the Related Art Conventionally, for example, when a slurry in which a Ziegler-based catalyst (average particle size of about 1 to 100 μm) for producing polyolefin is suspended in an inert solvent is supplied from a catalyst storage tank to a reaction tank, The method of supply by a metering pump is generally adopted. In such a supply method using a pump, if the concentration of the catalyst slurry is high, a so-called skimming phenomenon (a phenomenon in which the solvent is preferentially supplied and fine solids are concentrated in the system to cause poor flow) occurs, and the supply pipe The catalyst cannot be stably supplied because of clogging of the catalyst and difficulty of quantitative supply of the catalyst. Therefore, it was necessary to dilute the slurry concentration with the solvent to about 0.01 to 0.5% by weight and supply it. However, when the catalyst concentration is diluted with a solvent, the catalyst activity is lowered due to impurities in the solvent, and since it is necessary to separate and remove a large amount of the solvent in the post-treatment step, a large amount of energy is required and resource saving is also achieved. Not preferable.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to stably supply a catalyst slurry to a reaction tank without blocking the catalyst supply pipe even when a high concentration catalyst slurry is used. Is to provide a method that can.

[0004]

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, provided a specific catalyst supply device between the catalyst storage tank and the reaction tank and set the internal pressure of the catalyst storage tank. The present invention has been completed by finding that the catalyst slurry can be stably supplied by keeping the pressure higher than the internal pressure of the reaction tank without blocking the supply pipe.

That is, the gist of the present invention is to provide a catalyst slurry between a catalyst storage tank and a reaction tank when the catalyst slurry obtained by suspending a solid catalyst in an inert solvent is supplied from the catalyst storage tank to the reaction tank. A catalyst supply device having a rotating body having a flow path is provided to maintain the internal pressure of the catalyst storage tank higher than the internal pressure of the reaction tank, and rotate the rotating body to alternately connect the catalyst storage tank and the reaction tank. And shutting off the catalyst slurry.

Hereinafter, the present invention will be described in detail with respect to a method of supplying a catalyst slurry (hereinafter, simply referred to as a catalyst) for an olefin polymerization reaction. First, referring to the drawings, FIG. 1 is an explanatory view showing an outline of a process of the present invention, FIG. 2 is a schematic front view of a catalyst supply device, and a catalyst flow portion shows a cutaway cross section. FIG. 3 is a perspective view showing the appearance of the catalyst supply device of FIG.
FIG. 4 is an explanatory view showing a state when the catalyst channel is opened / closed in the process of FIG. 1, and FIG. 5 is a table showing supply test data when the catalyst is supplied under a predetermined condition.

In FIG. 1, 1 is a catalyst flow section of the catalyst supply apparatus shown in FIGS. 2 and 3, 2 is a catalyst outflow line from the catalyst flow section 1, 3 is a reaction tank, 4 is a monomer supply line, 5
Is a co-catalyst supply line, 6 is a catalyst storage tank, 7 is a catalyst, 8 is a pump, 9 is a catalyst return line, 10 is a catalyst passage of a valve body, 1
Reference numeral 1 is a catalyst inflow line to the circulation unit 1. The catalyst storage tank 6 includes a catalyst inflow line 11, a catalyst flow path 10, and a catalyst outflow line 2.
Is connected to the reaction tank 3 via.

The catalyst 7 in the catalyst storage tank 6 is supplied to the reaction tank 3 through the catalyst inflow line 11, the catalyst flow path 10 of the valve body, and the catalyst supply line 2. On the other hand, the cocatalyst and the monomer are appropriately supplied to the catalyst supply line 2 from the respective supply lines 4 and 5. In addition, the catalyst in the catalyst inflow line 11 is transferred to the catalyst storage tank 6 by the return line 9 via the pump 8 as necessary.
Will be returned to.

According to the method of the present invention, in the process shown in FIG. 1, a specific catalyst supply device is provided between the catalyst storage tank and the reaction tank, and the pressure of the catalyst storage tank 6 is set higher than that of the reaction tank 3. The main point is to keep the difference between the two pressures within a predetermined range. 2 and 3 show an outline of an example of a catalyst supply device used in the present invention, FIG. 2 is a schematic front view showing a cross section of a catalyst flow portion, and FIG. 3 shows an appearance of the device. It is a perspective view.

In FIGS. 2 and 3, reference numeral 12 denotes a thick-walled cylindrical main body of the catalyst supply device, and 13 is a truncated cone-shaped valve body having the catalyst flow passage 10 in the main body 12 of the supply device so as to be rotatable in the axial direction. It has been inserted. 14 is a catalyst inflow port, 15 is a catalyst outflow port, 16 is a catalyst return port, 17 is a supply port for co-catalyst and monomers, and 18 is a Teflon sheet fitted and fixed to the outer peripheral portion of the valve body 13. A communication hole 19 is narrowed in the same direction as the inlet 14 and the catalyst outlet 15.

A shaft 20 is provided on the valve body 13, and a gasket 21 is inserted between the shaft 20 and the valve body 13.
The shaft 20 is connected to a drive shaft 23 via an adapter-22,
When the drive shaft 23 is rotated by the hydraulic motor 24 as a drive source, the shaft 20 is also rotated. Is configured.

Above the adapter 22, a hydraulic motor 24 via a frame 25, a limit switch 26 for detecting the rotational movement of the drive shaft 23, and a speed control (not shown).
The valve element 13 is adjusted so that it can be rotated and stopped by these actions.

Next, according to the process shown in FIG.
A case of carrying out the method of the present invention using the catalyst supply device shown in FIG. 3 will be described. A catalyst having a high concentration of a solid catalyst suspended in a solvent, preferably 10 to 30% by weight, particularly preferably 15 to 25% by weight, is filled in a catalyst storage tank 6 and pressurized with an inert gas such as nitrogen to obtain a catalyst. The pressure (P ₁ ) in the storage tank 6 is made higher than the pressure (P ₂ ) in the reaction tank 3, and the pressure difference (P ₁ −
P ₂ ) is kept within a predetermined range. The preferred pressure difference between the two is 0.1 to 4 kg / cm ² , particularly preferably 0.5 to 2
It is kg / cm ² . If the pressure difference is less than 0.1 kg / cm ² , the flow passage is easily blocked, and if it exceeds 4 kg / cm ² , there is a problem in the life and durability of the valve body.

Normally, the pressure in the reaction tank is kept constant, and the operation is carried out. Therefore, in order to maintain the above-mentioned pressure difference, the pressure in the catalyst storage tank may be appropriately adjusted. As a method of maintaining the pressure of the catalyst storage tank, a method of adjusting the rotation speed of the shaft 20 to repeatedly rotate and stop the valve body 13 in the clockwise direction and the counterclockwise direction is adopted.

For example, the valve body 13 in the state (A) (flow passage closed) in FIG. 4 is rotated clockwise to go to the state (B) (flow passage open) and then to the state (C) (flow). It stops at (road block) and then returns from the state of (C) to the state of (A) via the state of (B). At this time, by controlling the size of the diameter of the catalyst passage 10 of the valve body 13 and the rotation speed of the valve body 13, the supply amount of the catalyst can be controlled appropriately.

The time required for the above operation is usually a very short time of several seconds, and the catalyst is supplied in the momentary state (B). Therefore, the flow of the catalyst does not become stagnant in the catalyst outflow line 2 to cause the blockage. The method of rotating the valve body 13 is not limited to the above method, and any method may be used as long as it can maintain the pressure difference between the catalyst storage tank and the reaction tank within the above predetermined range.

FIG. 5 shows that the pressure difference (P ₁ -P ₂ ) between the pressure in the catalyst storage tank (P ₁ ) and the pressure in the reaction tank 3 (P ₂ ) is ₁ using a catalyst having a slurry concentration of 25% by weight. It is maintained at kg / cm ² and the valve body has a flow path port diameter (inner diameter) of 6 mm, 8 mm, 10 mm and 12 mm, and the catalyst is supplied by changing the rotation time of the valve body. It shows the measurement result of the catalyst supply amount per one-time operation in the case.

The vertical axis of FIG. 5 indicates that the valve body in FIG. 4 is (A) →
The amount of catalyst supplied per operation (cc / time) when operating from (B) to (C) or from (C) to (B) to (A). From (A) → (B) → (C) or (C) → (B) →
Indicates the time (seconds) required to operate up to (A). FIG. 5 shows that in any case, the catalyst can be efficiently supplied within an extremely short time, and the supply amount of the catalyst can be adjusted by the rotation speed.

[0019]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples as long as the gist thereof is not exceeded.

Example 1 In the polymerization process shown in FIG. 1, the catalyst supply device shown in FIGS. 2 and 3 was used, and the temperature was 70 ° C. and the pressure was 30 kg / cm in the reaction tank 3.
Slurry polymerization reaction of propylene was carried out under the condition of ² . As catalyst 7, 220 g of titanium trichloride was added to 100 parts of n-hexane.
A slurry (catalyst concentration: 25% by weight) suspended in 0 ml (660 g) was used. Charge the catalyst 7 in the catalyst storage tank 6 (internal volume 15 l),
Internal pressure of 32 kg / cm ² (2 kg / cm ² from the reaction tank)
(High).

The valve body 13 having the catalyst channel 10 having a diameter of 6 mm and a length of 30 mm is rotated, and the rotation time from (A) to (B) to (C) in FIG. 4 is set to 0.3 to 1.0 seconds, The state of (B) is 3 to 6 in 1 hour.
I made it work twice. The catalyst supply and the reaction were continued for 120 hours under the above conditions, but no clogging of the catalyst supply line by the catalyst was observed. The content of volatile components in the obtained product polypropylene was 0.3% (weight) or less.

[0022]

According to the present invention, a high-concentration catalyst can be stably supplied without blocking the supply line, and the catalyst can be supplied by controlling the rotational speed of the valve body. It is possible to adjust the amount. Also,
The amount of solvent can be significantly reduced compared to the conventional supply method, which greatly contributes to resource saving and improvement of product unit price. Further, with the significant reduction in the solvent, it is possible to significantly reduce the mixture of volatile components derived from the solvent into the product in the drying step of the product polymer.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an outline of a process of the present invention.

FIG. 2 is a schematic front view of a catalyst supply device used in the present invention, showing a cutaway cross section of a catalyst flow portion.

FIG. 3 is a perspective view showing an appearance of the catalyst supply device of FIG.

FIG. 4 is an explanatory diagram showing an open / closed state of a catalyst flow path of the valve body in FIG. 1.

FIG. 5 is a chart showing the results when a catalyst is supplied under predetermined conditions according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 catalyst distribution part 2 catalyst outflow line 3 reaction tank 4 monomer supply line 6 catalyst storage tank 10 catalyst flow path of valve body 11 catalyst inflow line 12 catalyst supply device body 13 valve body

Claims (3)

[Claims] 1. When a catalyst slurry prepared by suspending a solid catalyst in an inert solvent is supplied from a catalyst storage tank to a reaction tank, a rotation having a flow path of the catalyst slurry between the catalyst storage tank and the reaction tank. A catalyst supply device provided with a body, maintaining the internal pressure of the catalyst storage tank higher than the internal pressure of the reaction tank, and rotating the rotating body to alternately connect and disconnect the catalyst storage tank and the reaction tank. And a method of supplying the catalyst slurry. 2. A catalyst slurry in which 10 to 30% by weight of a solid catalyst is suspended in an inert solvent as the catalyst slurry.
2. The method for supplying a catalyst slurry according to claim 1, wherein the catalyst slurry is used. 3. The internal pressure of the catalyst storage tank is less than that of the reaction tank.
The method for supplying a catalyst slurry according to claim 1, wherein the catalyst slurry is maintained at a high level of 1 to 4 kg / cm ² .