PROCESS FOR IMPROVING THE OPERATIONS OF A POLYMERISATION PLANT

Petrochemical complex containing an olefin monomer polymerization plant having at least one polymerization reactor and an optional degassing section. The polymerization reactor contains process hydrocarbons consisting of the monomer, the optional comonomer(s) and optionally at least one inert hydrocarbon diluent, together with aluminum containing compound(s). The polymerization plant includes liquid purge stream(s) which contain aluminum containing compounds and optionally polymer fines, together with accumulated hydrocarbons which are different from the process hydrocarbons and which are hydrocarbons containing at least 4 carbon atoms. The petrochemical complex also contains a multipurpose hydrocarbon treatment unit which separates the liquid purge stream(s) into one stream having substantially all of the aluminum containing compounds and optional polymer fines, and one stream containing the accumulated hydrocarbons. The petrochemical complex also contains an upgrading unit for the treatment of the accumulated hydrocarbons which also produces the fresh monomer and/or comonomer for the polymerization reaction.