There are two drums in a delayed coker unit that work consecutively while in operation. When one drum is functioning, the other drum is being de-coked.
The switching valve is required to direct hot feed to either drum A or drum B. The valve also has the bypass position to divert flow back to the fractionator for warmup or during emergencies.
The bypass has the same port dimension as the main drum feed lines. The control package also has the capabilities of providing multiple intermediate positions to provide the capability to warm the new drum while slowly reducing feed to the live drum.
These systems contain sticky residue, solids and other system contaminants. The switch valve is the most critical valve in the unit.
