| 摘要 |
A method and apparatus for decoking and suppressing coke formation during pyrolysis has been discovered that does not require complete shut down of the pyrolysis furnace. For the decoking step, the hydrocarbon feed is cut off to one or more coils for usually less than about three hours during which a decoking additive is added to the steam flow in that coil. This additive is comprised of an aqueous solution of a group IA metal salt and a group IIA metal salt and catalyzes the coke removal. The hydrocarbon feed continues in the other coils during this procedure. After decoking, a suppression additive also comprising group IA and IIA metals is added to the steam and hydrocarbon feed. This suppression additive will melt onto the inner surfaces of the pyrolysis furnace coils, coating the coils with a glass layer which inhibits coke formation. The apparatus of the invention is particularly suited for introducing the additives of the invention into the steam flow at a desired drop size without touching the sides of the coil. |
