Method and apparatus for the preparation of a polyolefin

A method (100) is proposed for the preparation of a polyolefin from olefin monomers, wherein the olefin monomers are subjected to one or more polymerisation steps (13), in which a proportion of the olefin monomers are catalytically reacted to form the polyolefin, while the olefin monomers that are not reacted in the polymerisation step or steps (13) are at least partly transferred into one or more gaseous, monomer-containing purge streams (g, h), which additionally contain(s) one or more aluminium organic compounds, which comprise one or more co-catalysts used in the polymerisation step or steps (13) and/or one or more compounds formed from the co-catalyst(s). It is provided that, downstream of one or more olefin synthesis steps (21), the gaseous, monomer-containing purge stream or streams (g, h) are brought into contact with a crude gas mixture (p, r) formed using a product mixture from the olefin synthesis step or steps (21) and are subjected to a caustic wash (26) together with the crude gas mixture (p, r). The present invention also relates to a corresponding apparatus.