Delayed Coking – Operations and Safety

[4 drums coker]

Facilitators – Gary Gianzon, Marathon Garysville
Steve Carlisle, LyondellBasell

1. Hot Drums and Blowouts
Longer Steam out to back warm decreases hot drum. 30 minutes is minimum, 1 hour is ideal.
Higher back pressure during quench improves back warm. Higher than coking pressure would be ideal.
Higher steam rate prevents bed collapse.
Coke drum inlet temperature is critical at reducing hot drums. Above 900F is recommended.
Quench water totalizer, sour water totalizer, coke drum pressure, drum skin temperatures are parameters that should be monitored for proper quench of drum.

2. Coke Drum Interlocks
Develop procedure and training for operator to verify stem position.
Verify that the temperature at midpoint rises before switching to the other drum. This could be part of an interlock or procedure.
Most is electrically actuated. Once refiner said that they use hydraulic actuator with good success.

3. Coke Drum Egress
Remote egress on the top of the coke drum is ideal.
Most use remote stairs (60 ft from the cutting deck) and other uses baker shouts
Water deluge on the top, unheading, and stairways
Ideal to reduce personnel on the top deck by remote cutting and automated switching.

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