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RE: Coke Drum Foam-over Emergency Procedure


Gary Pitman

From the ‘How to Coke Book’

Signs of foam

1. Early, unusual or sudden drum level detector activity by any one of the drum level detectors.

2. Unusual blips, sudden or even gradual increases in coke drum pressure (sign of liquid/foam carrying over and briefly restricting normal vapor flow).

3. Increase in wet gas production (causes higher drum velocities and foaming).

4. Sharp increase(s) in combination tower level.

5. Decrease in fresh feed when recycle coking (reductions caused by material entering the tower from the coke drum overhead line).

6. Decrease in combination tower chimney temperature (temperature will drop as less drum vapors and more heavy liquid enters the tower in its place).

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