METHODS FOR CONTROLLING ALUMINIUM ALKYL FEED TO SLURRY POLYMERISATION PROCESS Russian patent published in 2019 - IPC C08F10/02 C08F2/14 

FIELD: technological processes.

SUBSTANCE: invention relates to a slurry polymerisation process for producing polyethylene. Method comprises feeding into a reactor ethylene, a Ziegler catalyst, fresh aluminium alkyl and a diluent collected from fresh diluent, recycled slurry medium or mixtures thereof and, optionally, quantities of hydrogen, and, optionally, quantities of C₃-C₁₀ alpha olefins as comonomers. Reactor is a single reactor of one polymerisation reactor installation or a cascade of reactors consisting of two or more polymerisation reactors. Ethylene, Ziegler catalyst, fresh alkyl aluminium, diluent and, optionally, a comonomer and hydrogen react as a slurry in the reactor at a reactor temperature of 60–95 °C and reactor pressure of 0.15–3 MPa. Supply of fresh aluminium alkyl to the polymerisation reactor is adjusted to maintain the estimated concentration of aluminium alkyl in the recycled slurry medium.

EFFECT: adjustment of the concentration of alkyl aluminium in the slurry medium, which is re-fed into the reactor system for slurry polymerisation of ethylene to improve yield and selectivity, despite changes in the grades of polyethylene in the reactor or levels of catalytic poison.

13 cl, 2 dwg