FIELD: chemistry.
SUBSTANCE: invention relates to a process of converting hydrocarbon feed streams by thermal steam cracking to produce at least one olefin containing product stream comprising at least ethylene and propylene by at least partial conversion of a hydrocarbon feed stream in at least one cracker (2). The process is characterized in that the hydrocarbon feed stream is converted under mild cracking conditions in the cracking furnace (2), whereby the soft cracking conditions mean that the ratio of propylene to ethylene is 0.85 to 1.6 kg/kg at the outlet of the cracking furnace, and the hydrocarbon feed stream mainly contains hydrocarbons having a maximum number of carbon atoms 5.
EFFECT: increase in the yield of propylene.
15 cl, 5 dwg
