Patent ID: 8864977

Claim:
A process for the on-stream decoking of a furnace having a convection section, a radiant section, a crossover from the convection section to the radiant section, and a quench system, the process comprising the steps of: (a) providing a hydrocarbon feed to a first portion of the convection section via a plurality of tubes of a first tube bank to produce a pre-heated hydrocarbon feed; (b) removing the pre-heated hydrocarbon feed from the furnace; (c) providing the pre-heated hydrocarbon feed to a second portion of the convection section via a plurality of tubes of a second tube bank to produce a heated hydrocarbon feed, wherein the second tube bank is located downstream of the first tube bank; (d) removing the heated hydrocarbon feed from the furnace; (e) providing the heated hydrocarbon feed to a third portion of the convection section via a plurality of tubes of a third tube bank to produce a re-heated hydrocarbon feed, wherein the third tube bank is located downstream of the second tube bank; (f) removing the re-heated hydrocarbon feed from the furnace; (g) separating from the removed re-heated hydrocarbon feed an overhead stream, and then providing the overhead stream to a fourth portion of the convection section via a plurality of tubes of a fourth tube bank to produce a heated overhead stream, wherein the fourth tube bank is located downstream of the third tube bank; (h) selecting at least one but fewer than all of the first, second, third, and fourth tube banks, and terminating hydrocarbon flow to a portion of the plurality of tubes of the selected tube banks; and (i) supplying a decoking feed comprising steam to the portion of the plurality of tubes of the selected tube banks to effect removal of coke accumulated on the interior of radiant coils and quench system components fed by such tubes while maintaining a temperature at the convection section to radiant section crossover of below about 788° C.