FIELD: chemistry.
SUBSTANCE: obtaining of olefin products is carried out by thermal vapour-phase cracking of the first furnace feedstock from hydrocarbons in, at least, one first cracking furnace (2) and the second furnace feedstock from hydrocarbons in, at least, one second cracking furnace (1). The first furnace feedstock in, at least, one first cracking furnace (2) is, at least, partially, converted to the first product stream (F), and the second furnace feedstock in, at least, one second cracking furnace (1), at least, in part, is converted to the second product stream (F'). The first pyrolysis oil (P) is separated from the first product stream (P), and the second pyrolysis oil (P*) is separated from the second product stream, and the first pyrolysis oil (P) is, at least, partially, treated chemically. The process is characterized in that the first pyrolysis oil (P) downstream of the chemical treatment is returned, at least, in part, as a furnace feedstock (P') to, at least, one first cracking furnace (2), the second pyrolysis oil is removed from the ethylene installation used in the method. The first and the second product streams (F, F') downstream of the separation of the first and the second pyrolysis oils (P, P*) are combined into a common product stream and further co-processed to produce, at least, one olefin product (K, L), and, at least, one first cracking furnace (2) and, at least, one second cracking furnace (1) are operated under various cracking conditions, whereby the first furnace feedstock that is fed to, at least, one first cracking furnace (2), includes heavier fresh feedstock (A), which predominantly comprises hydrocarbons having a boiling temperature, which is higher than 180°C and/or, at least, one first cracking furnace (2) is operated under cracking conditions that correspond to the ratio of propylene to ethylene in the first product stream (F) at the outlet of, at least, one first cracking furnace (2) from 0.7 kg/kg to 1.6 kg/kg.
EFFECT: optimisation of the process for the obtaining of olefins, provided by varying the conditions for their obtaining, taking into account different technological equipment for cracking.
20 cl, 4 dwg
