Operations

  1. Drilling
        1. Drill stem stuck in drum
        2. Brittle coke collapsing on drill stem
        3. Changing feed w/ out changing procedures
        4. Slushy coke, soft coke hard to drain, not completely drained.
        5. Increasing pilot hole
        6. Stronger tool
        7. Auto switch from drilling to cutting
              1. Helps prevent stuck drill stem
        8. Correct drilling procedures
  2. Blowouts sometimes but not often
        1. Shorter cycles will increase profitability of blowouts
        2. Using TC to ensure drum (coke) temperature is cold enough to prevent blowouts
  3. How to know when drilling & decoking is complete
        1. Sound (human hearing)
        2. Vibration (accelerometers)
        3. Microphones
              1. Water jet on steel vs. on coke
                    1. Different response
        4. Visual inspection from top

Process

  1. Coke Accumulation
        1. Transfer line
              1. Clean at shutdown opportunity, design short
              2. Spalling coke can lead to valve pluggage or erosion/fire
        2. Drum vapor line
              1. HVGO/LVGO/Slop/Insulation removal mitigation
              2. Clean during decoke
  2. Fractionator Coke Accumulation              
        1. Consensus, most coke comes from drum
              1. Used a metal balance to prove origin
        2. Sparger system used, filter or drum
  3. Some new designs are using Stripped Sour Water as quench water make up.  Quality control is important to limit smell issues
  4. Good antifoam dilution is critical to effectiveness.
        1. Inline or in the tank with a mixer

Heaters

  1. Safety RV on heater outlet confidence in working
        1. Use of flush with steam both sides of RV
        2. Design for PSO
  2. APH Advisable Pro/Con
        1. Pros
              1. Energy Savings
              2. Less emissions
              3. Economics
        2. Cons
              1. More equipment & energy uses(Fans)
              2. More costly design
              3. Higher radiant flux
              4. Higher tube metal temperature
              5. Air temperature

Safety

  1. Water spray on drum top (located on the highest deck of drum structure)
        1. Activated by Fuse Plug
        2. Activated by Smoke Detectors Plug
              1. Take care with location of the plugs to avoid spurious trips during drum opening
  2. Water Monitors
        1. W.M. located at highest deck (Man Vac)
        2. W.M. (too high capacity) located outside drum structure (EL.O)
  3. Coke drum fire fighting
        1. Water spray on drums
        2. Water monitors
  4. Preventing liquids from being sent to fractionator through condensate vessel gas outlet line
  5. How to control people in the working area