Process for improving the operations of a polymerisation plant

Petrochemical complex comprising an olefin monomer polymerisation plant comprising at least one polymerisation reactor and an optional degassing section, wherein

• the polymerisation reactor comprises process hydrocarbons consisting of the monomer, the optional comonomer(s) and preferably at least one inert hydrocarbon diluent, together with aluminium containing compound(s);
• and
• the polymerisation plant comprises liquid purge stream(s) which comprises aluminium containing compounds and potentially polymer fines, together with accumulated hydrocarbons which are different from the said process hydrocarbons and which are hydrocarbons containing at least 4 carbon atoms,
• characterised in that the petrochemical complex also comprises a multipurpose hydrocarbon treatment unit which separates the liquid purge stream(s) into
• one stream comprising substantially all of the aluminium containing compounds and potentially polymer fines, and
• one stream comprising the accumulated hydrocarbons.