METHOD OF PRODUCTION OF LOWER OLEFINS Russian patent published in 2008 - IPC C10G9/14 C07C4/04 

FIELD: chemical and petro-chemical industries.

SUBSTANCE: proposed method includes preliminary thermal pyrolysis of gasoline fraction at initial boiling point of 195°C in tubular furnace in two stages: first at temperature of 805-820°C continued for 24-120 hours and then at temperature of 820-825°C continued for 24-72 hours. Time of contact at preliminary pyrolysis is 0.3-0.65 s and mass ratio of raw material to water vapor ranges from 1.0:0.3-0.9. In the course of preliminary pyrolysis, hydrocarbon product and amorphous coke are obtained on inner surfaces of tubular furnace coils. Subsequent pyrolysis is carried out at temperature of 825-845 C, time of contact of 0.3-0.65 and mass ratio of raw material to water vapor ranging from 1.0:0.3-0.9.

EFFECT: increased time of furnace inter-regeneration period in the course of thermal pyrolysis; high yield of lower olefins, ethylene and propylene in particular.

2 cl, 2 tbl, 8 ex