JPS5879533A - Supplying method for catalyst - Google Patents

Abstract

PURPOSE:To permit stable supplying by discharging the slurry from a storage tank continuously by the use of a supply system provided with a supply passage communicating from the passage for discharging from the slurry storage tank to a reaction system and a circulating passage returning to the storage tank. CONSTITUTION:A passage 3 for discharging of slurry from a storage tank 1 is connected to a supply passage 4 to a reaction system and a circulating passage 5 to the tank 1. Timer valves 8, 9 are provided to the passage 4 and the passage 5, and are so arranged that when one valve 8 is opened by the operation of a rotary actuator 7 the other valve 9 is closed and when the valve 8 is closed, the other valve 9 is opened. Contact slurry is discharged continuously at a constant rate from the passage 3 by a pump 6 and the circulation and supply are accomplished mutually by the opening and closing of the valves 8, 9 without stoppage in the passages.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for supplying a slurry of solid catalyst to a reaction system.

There have already been many proposals for methods of polymerizing olefins in the gas phase using solid catalysts. Catalysts have been significantly improved in recent years, and the yield of olefin polymer produced per unit weight of catalyst has increased dramatically, resulting in the need for a very small amount of solid catalyst to be supplied to the reaction system. . In continuous polymerization, the catalyst must be supplied to the reaction system in small quantities, which is technically difficult even with existing equipment, and has many problems to be solved. Particularly in the gas phase polymerization of olefins, when a solid catalyst is dispersed in a diluent and supplied in the form of a slurry, it is desirable to use as little diluent as possible in consideration of post-treatment of the polymerization. Therefore, solid catalyst slurry is supplied to the reaction system in small quantities, but the supply rate is slow.
In addition, the solid catalyst may settle in the supply passage, and as a result, it becomes difficult to supply a specified amount of catalyst to the reaction system. Furthermore, there were few pumps that could supply slurry in small quantities with high accuracy. In view of the above-mentioned current situation, the present inventors conducted studies to improve the drawbacks, and as a result, they were able to use a relatively large-capacity pump. Moreover, we have developed a method that can stably supply slurry to the reaction system in small amounts.

That is, the present invention provides a method for supplying a solid catalyst slurry to a reaction system, using a catalyst supply system including a supply passage leading from a passage for extracting the slurry from a storage tank to the reaction system and a circulation passage returning to the storage tank. The slurry of the solid catalyst is intermittently supplied to the reaction system by continuously extracting the slurry from the tank and alternately repeating the shutoff of the supply passage and the conduction of the circulation passage, and the conduction of the supply passage and the shutoff of the circulation passage. A method for supplying a catalyst is characterized in that:

Examples of solid catalysts include Ziegler type titanium catalyst components for olefin polymerization and Phillips type chromium catalyst components. A typical titanium catalyst component is a titanium compound supported on a magnesium compound, which contains magnesium, titanium, and a halogen as essential components, and may also contain an electron donor, other compounds, or functional groups. There is. Usually 1 to 100
The particle size is about μ, and the surface area is preferably 1.0
m2/g or more.

The dispersion medium for the solid, catalyst slurry is, for example, a hydrocarbon, an aliphatic hydrocarbon such as butane, pentane, hexane, heptane, octane, kerosene, or an alicyclic hydrocarbon such as cyclopentane, methylcyclopentane, cyclohexane). Group hydrocarbons - aromatic hydrocarbons such as benzene, toluene, xylene, halogenated hydrocarbons such as ethyl chloride, ethylene chloride, butyl chloride, chlorobenzene, mixtures thereof, and the like.

The concentration of the solid catalyst in the slurry is arbitrary, but for example, 1
High concentrations such as 0 to 100 g/l may be used. Of course, the concentration may be lower than the above range.

An example of a catalyst supply system is shown in FIG. A storage tank 1 for the solid catalyst slurry is equipped with a stirrer 2 to stir and mix the solid catalyst so as not to cause sedimentation. A passage 6 for extracting the catalyst slurry from the storage tank 1 is a supply passage 1 to the reaction system.
The supply passage 4 and the circulation passage 5 are provided with timer valves 8 and 9, and when one valve 8 is opened by the operation of the rotary actuator 7, the other valve is opened. Valve 9 is closed, and when valve 8 is closed, the other valve 9 is opened. A certain amount of catalyst slurry is continuously extracted from the extraction passage 3 by the pump 6, and by opening and closing the valves 8 and 9,
The circulation is stopped while the catalyst is being supplied to the reaction system, and the catalyst is circulated to the storage tank while the supply to the reaction system is being stopped, so that it does not stop in the extraction passage, and therefore no sedimentation of the catalyst occurs.

The amount of catalyst to be supplied to the reaction system can be controlled by adjusting the opening and closing times of the timer valve 8 (9), thereby making it possible to supply the catalyst at a constant rate, albeit intermittently. A check valve 10 is provided in the supply passage 4 to prevent backflow of the catalyst, and a purge passage 11 is provided near the outlet of the check valve.
By flowing the purging fluid through the passage 11 so that the catalyst carried after the check valve does not remain in the passage, it is possible to completely supply the catalyst to the reaction system. As the purging fluid, in olefin polymerization, gas or liquid of the olefin to be polymerized, hydrogen, or an inert fluid can be used.

According to the method described above, a pump with a large capacity can be used compared to a method that continuously supplies the reaction system. Further, even if the slurry concentration is increased, there is no fear of catalyst sedimentation or clogging, and the slurry can be stably supplied to the reaction system.

Next, an example will be explained.

Example [Catalyst synthesis] 2 g of anhydrous MgO7127 in a 200 ml flask
1 decane 23 ml! and 2-ethylhexanol 2
After adding 5 m1'5:: and heating reaction at 120°C for 2 hours to make a homogeneous solution, 1.68 m of ethyl benzoate was added.
, / were added.

T1T1C142O0 was placed in a 400 ml flask, and while the flask was kept cooled at -20°C, the entire amount of the homogeneous solution was added dropwise over 1 hour, and then the temperature was raised to 80°C.

After stirring at 80°C for 2 hours, the solid part was collected by filtration,
Suspend this in new T 1C (14200"N, 9
Stirred at 0°C for 2 hours. After the stirring was completed, the solid portion collected by thermal pyrolysis was sufficiently washed with hot kerosene and hexane to obtain a titanium catalyst component. The catalyst contains 4.5 wt% Ti,
(:' Contains 160wt%, Mg13wt%, average particle diameter 15μ, specific surface area 195m2/g.

[Catalyst pretreatment]

The obtained catalyst slurry was 5 mmo in terms of Ti atoms.
After resuspending in hexane at a ratio of l/l, triethylaluminum was added at a ratio of 15 mmol/l, and propylene was roughly supplied at a ratio of 3 g per 1 g of titanium catalyst component, and 40" The treatment was carried out with C. The catalyst particle size after treatment was 50μ on average.

[Catalyst supply]

While circulating the catalyst slurry obtained through the above pretreatment using a diaphragm pump at a rate of 20 d/hr, the valve in the reaction system line was opened for 1.5 seconds and the opening frequency was set to 40 d/hr.
When the reactor was set to once every second and operated, the catalyst slurry could be stably supplied to the reaction system at an average rate of 0.451/hr.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an outline of catalyst supply. 1. Storage tank 2. Stirrer 3, extraction passage 4 supply passage 5 circulation passage
6 Pump Z rotary actuator
86 Valve 9 Nonolube Applicant Mitsui Petrochemical Industries Co., Ltd. Agent Kazu Yamaguchi

Claims (1)

[Claims] (1) In a method for supplying a solid catalyst slurry to a reaction system, a catalyst supply system including a supply passage leading from a passage for extracting the slurry from a storage tank to the reaction system and a circulation passage returning to the storage tank is used. The slurry of the solid catalyst is intermittently supplied to the reaction system by continuously extracting the slurry and alternately closing the supply passage and opening the circulation passage, and turning on the supply passage and shutting off the circulation passage. A method for supplying a catalyst, characterized in that: