Patent ID: 7820035

Claim:
A process for cracking a heavy hydrocarbon feedstock, said process comprising: (a) heating a heavy hydrocarbon feedstock in a pyrolysis furnace, said pyrolysis furnace comprising a radiant section and a convection section; (b) mixing the heated heavy hydrocarbon feedstock with a liquid outside of said pyrolysis furnace in a first sparger of a double sparger, and with primary dilution steam stream in a second sparger of said double sparger to form a mixture stream, and heating the mixture stream in said first convection section tube bank of said pyrolysis furnace; (c) flashing the mixture stream to form a vapor phase and a liquid phase; (d) removing the liquid phase in a flash/separation vessel; (e) cracking the vapor phase in a radiant section of the pyrolysis furnace to produce an effluent comprising olefins; and (f) quenching the effluent using a transfer line exchanger, wherein the amount of the liquid relative to the steam mixed with the heavy hydrocarbon feedstock is varied in accordance with at least one selected operating parameter of the process.