Neste Oy

Borealis Polymers Oy

Borealis A/s

Ari Palmroos

Jouni Takakarhu

Antero Ahvenainen

Ali Harlin

Klaus Nyfors

Kalle Kallio

Auli Nummila-Pakarinen

Hilkka R Knuuttila

Harri Hokkanen

Hannu Salminen

Henrik Andtsjo

Aimo Sahila

Kari Sarantila

Kari Matilainen

Markku Savolainen

Timo Blomqvist

Method and apparatus for taking sample

Process for manufacturing LLDPE polymers

A process for producing polyethylene compositions in the presence of a catalytic system of ethylene polymerizing catalyst and cocatalyst in a multistage continuous reaction sequence consisting of successive liquid phase and gas phase polymerizations is disclosed. In the first step of the process, ethylene and optionally hydrogen and comonomer are polymerized in a first loop reactor in a low boiling hydrocarbon medium in the presence of ethylene polymerizing catalyst and cocatalyst. The reaction mixture is then removed and then transferred to a second loop reactor where polymerization is continued by addiing ethylene, hydrogen and optionally inert hydrocarbon, comonomers and cocatalysts. Thereafter, the reaction mixture is removed from the second loop reactor along with an essential part of the reaction medium and transferred to a gas phase reactor where polymerizing is continued in the presence of added ethylene and optionally hydrogen, comonomers and cocatalysts to form an end product. The residence time and reaction temperature being such that the proportion of the ethylene polymer produced in the first loop reactor to the end product of the process is between 1-20%.

Process for preparing polyethylene

Multi-stage process for producing polyethylene

The invention relates to a regulation method for regulating the temperature in a reactor utilized in the polymerization of olefines. A circulating gas is led to the reactor along a circulating gas flow line, and the circulating gas is cooled by leading part of the circulating gas flowing along a circulating gas flow line along a by-pass flow line through a cooler. A regulating device for the circulating gas inlet-flow temperature controls the amount of the circulating gas by-pass flow along a circulating gas by-pass flow line through the cooler such that the sum of the openings of a valve in the circulating gas flow line and a valve in the circulating gas by-pass flow line is maintained substantially constant in the range from about 90 to about 120%.

Regulation method for regulating the temperature in a reactor utilized

Growing community of inventors

Kerava, Finland

Ari Palmroos