Technology Type

In a modern Stirred Tank Reactor (STR) Slurry Process generally consist in a series of tow or three Reactors. The pressure in the Reactors is between 0.5 and 1 MPa, permitting the construction of large Reactors with up to 100 m³ Volume. The Reaction Temperature is between 80 and 90 °C, and typically Hexane is used as the Diluent. The main Feed to the Reactor consists of Recycled Diluent. A controlled amount of Ethylene Monomer, a Comonomer and Hydrogen as well as a Suspension of a Catalyst/Cocatalyst (Alkyl Aluminium) Mixture is fed to the Reactor. In the subsequent ‘Run-Down’ reactor(s), the dissolved Ethylene is almost completely consumed. The remaining Ethylene can be recovered and sent back to a nearby cracker or used as Fuel Gas. After leaving the Reactor, the Polymer Slurry is passed to a Centrifuge which removes most of the Solvent. In a Fluidised Bed Dryer, the Polymer is Dried in a Stream of Hot Nitrogen and freed of the remaining Solvent.

Source: European Commission, European IPPC Bureau, Aug 2007, Reference Document on Best Available Techniques in the Production of Polymers.