Patent ID: 7470409

Claim:
An apparatus for cracking a hydrocarbon feedstock containing resid, said apparatus comprising: (1) a convection heater for heating said hydrocarbon feedstock; (2) an inlet for introducing steam to said heated hydrocarbon feedstock to form a mixture stream; (3) a flash/separation drum for treating said mixture stream to form i) a vapor phase at its dew point which partially cracks causing a temperature decrease and partial condensation of said vapor phase in the absence of added heat, and ii) a liquid phase; said drum further comprising (I) a means for reducing or eliminating said partial condensation comprising an inlet for adding heated vaporous diluent to said flash/separation drum to an extent sufficient to at least partially compensate for said temperature decrease and dilute and superheat said vapor phase, the heated vaporous diluent being introduced to the flash/separation drum through an inlet above where the mixture stream is introduced; (II) a flash/separation drum overhead outlet for removing the vapor phase as overhead; (III) a flash/separation drum liquid outlet for removing said liquid phase as bottoms from said flash/separation drum; (4) a convection heater for heating the vapor phase; (5) a pyrolysis furnace comprising a radiant section for cracking the heated vapor phase to produce an effluent comprising olefins, and a convection section; and (6) means for quenching the effluent and recovering cracked product therefrom.