METHOD AND PLANT FOR STEAM CRACKING

The present invention relates to a method for converting one or more hydrocarbons by means of steam cracking, wherein one or more input streams (F) containing the one or more hydrocarbons (H) are led through one or more radiant zones (11) of one or more cracker furnaces (10), such that one or more product streams (C) are obtained; wherein the one or more radiant zones (11) are heated by the burning of heating gas (X) with combustion air (L); wherein at least part of the combustion air (L) is subjected to combustion air preheating (75); wherein steam (S, T) is produced from feed water (W); and wherein the feed water (W) is subjected to feed water preheating in one or more convection zones (12) of the one or more cracker furnaces (10). The combustion air preheating (75) is carried out, at least partly and/or at least some of the time, by the use of heat drawn from at least part of the feed water (W) upstream of the feed water preheating. The present invention also relates to a corresponding plant.