Coker Furnace On-Line Spalling. - “Safe, Clean, Proven, and Profitable."

On-line Spalling is an operation carried out in many Delayed Coker Units to remove coke deposits from the inside of coker furnace tube walls. This process is normally used in one furnace at a time of a multi furnace coker while the other furnace(s) remain in service. The procedure uses high velocity steam or boiler feed water, while thermally contracting and expanding the tubes. The procedure “spalls” the coke from the tubes while the contracting and expanding cracks and dislodges the coke from the tube walls and deposits the coke in the on-line coke drum.

Care must be taken in the design of an on-line spalling procedure to assure safety, to protect equipment, to protect piping, and to complete a good spall.

On-line spalling is one of three accepted methods for decoking a delayed coker furnace. Steam-air decoking and pigging are also used. On-line spalling offers the advantage of allowing the coker to continue in operation while the furnace tubes are being cleaned and has less environmental issues than steam air decoking. Pigging may still be required on occasions to bring the furnace back to start of run conditions.