The invention relates to a process for producing olefins from a feed
stream containing hydrocarbons by pyrolytic
cracking of the hydrocarbons in an autothermal reactor, said process comprising: pre-heating an
oxygen containing
stream and a
hydrogen and / or
methane containing
stream outside the autothermal reactor; feeding the pre-heated
oxygen containing stream and the pre-heated
hydrogen and / or
methane containing stream into a burner of the autothermal reactor; generating steam in a
combustion zone of the autothermal reactor; pre- heating a feed stream containing hydrocarbons outside the autothermal reactor; feeding the pre-heated feed stream containing hydrocarbons into the autothermal reactor; mixing the steam generated in the
combustion zone with the pre- heated feed stream containing hydrocarbons in a mixing and
cracking zone of the autothermal reactor, by feeding the steam and the pre-heated feed stream containing hydrocarbons into the mixing and
cracking zone from substantially opposite directions, and pyrolytically cracking the hydrocarbons to provide an
effluent containing olefins wherein the olefins comprise
ethylene and
acetylene; subjecting at least a part of the
effluent containing olefins to hydrogenation of
acetylene in the
gas phase in the presence of a heterogeneous catalyst at a temperature of at least 200 °C, thereby obtaining an
ethylene-enriched stream and heat.