Improving the Refinery Vacuum Heater

Sloley, A. W., Advisian (WorleyParsons Group)
Coking has long remained a key limit in crude vacuum heater performance. Many alternatives are available to reduce heater coking. These include dual-fired heaters, extended tube spacing (3-diameter) heaters, and velocity steam injection.

Another alternative that can be used in combination with any of the previous techniques is a cocurrent flow heater. In this heater, the passes are arranged to moderate the oil film temperatures and reduce coking rates. An analysis of the cocurrent flow heater is presented.