The present invention relates to a method for the preparation of linear alpha-olefins by oligomerization of ethylene in a reactor in the presence of a solvent and a catalyst, and the reator system therefore. The method is characterized in that from a discharge stream of the reactor comprising the solvent, catalyst, linear alphaolefins and substantially high molecular weight oligomers, the high molecular weight oligomers are separated, then diluted with a dilution medium and heated to about 13O DEG C to about 200 DEG C, the diluted high molecular weight oligomers being then transferred to a disposal device, wherein recycles for loop operation are established, and flow rates of the loop streams are from about 1 to about 50 m<3>/h.