Total Research & Technology Feluy

Total Petrochemicals Research Feluy

Alain Brusselle

Louis Fouarge

Daan Dewachter

Daniel Siraux

Franky Fant

Peter Stevens

Martine Slawinski

Olivier Miserque

Vincent Warichet

A method can include consecutively batch processing at least two different polyethylene grades in pellet form in a pellet handling unit. A ratio of a melt flow index (MI) of a first polyethylene in pellet form (MI) to a MI of a later processed polyethylene in pellet form (MI) can be smaller than 0.30. The method can include processing an intermediate polyethylene grade in pellet form. An amount of intermediate polyethylene grade processed can be at most 1/100of a handling capacity of the pellet handling unit. The intermediate polyethylene grade can have the same MI as the later processed polyethylene in pellet form.

Method for processing polyethylene

An apparatus may include a mud pot and a reflectometer to monitor a level of an interface between liquid diluent and catalyst slurry in the mud pot using reflectometry. The apparatus may include a mixing tank and a conduit to transfer catalyst slurry from the mud pot to the mixing tank. The apparatus may include a polymerization reactor and a conduit to provide catalyst slurry from the mixing tank to the polymerization reactor.

Method for monitoring the level of an ethylene polymerization catalyst slurry

The present invention relates to a method for consecutively producing at least two different polyethylene resins in one slurry loop reactor, comprising producing a first polyethylene resin in the presence of a Ziegler-Natta and/or a Chromium catalyst, and consecutively producing a second polyethylene resin in the presence of a metallocene catalyst, characterized in that the ratio of the melt flow index of the first produced polyethylene resin to the melt flow index of the second produced polyethylene resin is at least 0.3.

Method for producing polyethylene

A process includes preparing a diluted catalyst slurry in a catalyst slurry preparation system. The diluted catalyst slurry contains solid particulate catalyst and liquid hydrocarbon diluent. The catalyst slurry preparation system includes a mixing vessel with a top part, a bottom part and a rotatable impeller system which is actuated by a motor. The rotatable impeller system has a magnetic actuated agitator shaft which is positioned along a longitudinal axis of the mixing vessel and extends through the top part of the mixing vessel. At least two double-bladed hubs are fixed to the magnetic actuated agitator shaft.

Catalyst slurry preparation system and use thereof

The present invention relates to the use of a catalyst preparation system for the preparation of a diluted catalyst slurry. In particular, the invention relates to a catalyst preparation system comprising a mixing vessel for mixing a particulate catalyst and a liquid hydrocarbon diluent. According to the invention, diluted catalyst slurry is prepared in a mixing vessel comprising a rotatable axial impeller system comprising at least two double-bladed hubs. The invention also relates to a process for preparing diluted catalyst slurry for use in the preparation of a particulate polyethylene product in a loop reactor with the catalyst preparation system as described herein.

The present invention relates to a method for monitoring the level of an ethylene polymerization catalyst slurry in a mud pot (), whereby said catalyst slurry is prepared by introducing a solid catalyst and a liquid diluent in said mud pot (), and whereby through sedimentation an interface () is formed between said diluent and the obtained catalyst slurry, characterized in that said interface () is monitored with Time Domain Reflectometry.

The present invention relates to a method for feeding metallocene catalyst slurry to an olefin polymerization loop reactor () using a positive displacement device () positive displacement device comprising a first chamber and a second chamber, each chamber having an inlet and an outlet and each chamber comprising an ball arranged between the walls of said chamber, wherein said chambers are connected to each other by a pump chamber operably connected to a pump, wherein, the difference between the diameter of said ball and the diameter of said chamber is comprised between 5 to 200 times the average particle size (d50) of said catalyst.

Process for supplying catalyst to a polymerization reactor

The present invention relates to a process for preparing catalyst slurry in a catalyst slurry preparation system and supplying catalyst slurry to an ethylene polymerization loop reactor wherein an accurate control of the pressure within said catalyst slurry preparation system is provided. More particularly, the present invention provides a method for preparing a catalyst slurry and supplying said catalyst slurry to an ethylene polymerization loop reactor, said catalyst slurry comprising solid catalyst and a liquid hydrocarbon diluent, wherein said method comprises the steps of:

Pressure control of the catalyst mixing vessel

The present invention discloses a slurry loop reactor comprising at least two loop reactors connected in series and wherein the line connecting the two loops is subject to a dynamic pressure difference.

Dynamic pressure control in double loop reactor

The present invention relates to a method for determining activity of a catalyst in a polymerization process, said polymerization process comprising the steps of feeding a catalyst and a diluent into a storage vessel, to form a concentrated settled catalyst, feeding said concentrated settled catalyst into a mixing vessel equipped with mixing means and feeding hydrocarbon diluent into said mixing vessel, to form a diluted catalyst slurry, feeding said diluted catalyst slurry into a polymerization reactor via a volumetric pump, and feeding at least one monomer into said polymerization reactor to form a polymer. The method is characterized in that density of the diluted catalyst slurry is measured between an outlet of the mixing vessel and the volumetric pump, the amount of catalyst fed into the polymerization reactor is determined based on the measured density of the diluted catalyst slurry, and the amount of catalyst fed into the polymerization reactor is compared to the amount of the polymer formed to determine the activity of the catalyst. The invention also relates to a system suitable for carrying out the method.

Method and system for determining catalyst activity

The invention discloses a metallocene catalysed slurry polymerisation process of ethylene in the presence of a low concentration of scavenger. This allows improving the anti-sheeting of the reactor during the polymerisation process.

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Wilrijk, Belgium

Alain Brusselle