The original delayed coking process was extremely high risk, especially top and bottom unheading. Lower cycle times and different resid qualities may have introduced new issues and risks. Top and bottom unheading risks are greatly mitigated with slide gate valves. However, two different refineries have experienced three “Line of fire” incidents, one very serious, even with Delta Valves. This incident will be discussed in the hopes of preventing personnel exposure and injuries through awareness of the risks.
The delayed coker furnace is the heart of the unit. The process itself and decoking methods can cause erosion to the tubes and especially the u-bends. This part of the presentation will explore a refinery’s experience with Coker furnace tube thinning that was “unusual” compared to typical damage profile. Their inspection findings will be shared with the coking community to make everyone aware of this new damage mechanism. This refinery is also seeking feedback through this presentation from other sites to determine if this has been seen in other furnaces.