Tuesday Breakout Discussions
Design
1. Design regulations for venting
a. Were all waiting to see what happens with regards to EPAs future requirements
b. Eductor system, possible solution should have a vacuum breaker
c. Insulation support systems (birdcage)
d. Birdcage – Avoid clips on shell
e. Birdcage can also avoid damage on water insulation
f. Birdcage is also costly
g. Aero gel is a possible future material for coke drums
2. Design measures to reduce scaffolding and increase safety
a. Have walkways, platforms on structure for access egress, or to preplan scaffolding in the initial design
b. Rope access for inspection and minimal repair externally and internally on the drum.
c. Drum replacement tips
d. Remove derricks was less expensive, less exposure, safer
3. Plan ahead for replacement of drums 2 to 3 years. If you DONT you are forced into canned replacement.
Engineering
1. Factors that affect fatigue design
a. Wall Thickness: Uniform Wall; Integral reinforced nozzles
b. Operating practices, switch/quench cycle time are critical to reduce fatigue
2. Best Feed Nozzle Location
a. Not enough history with alternate feed nozzle location to evaluate
3. Recommended Material For New Drums
a. More information needed, not enough detailed study done.
Fabrication & Repair
1. Minimizing Circ Welds
a. Eliminate # of circ welds in quench zone
b. Prior to 01 lots of cracking 01 installed vertical plate design no cracking since
Fabrication & Repair
2. Inspection Criteria During Fabrication
a. Important to have excellent specs
i. Tolerances, i.e. matching plates roundness
b. Fabricator qualification
c. Enforcement of specification
4. Bulging
a. Repair
i. Overlay
b. Replace
c. Monitoring-strain gauges
d. Repair utilizing temper bead procedure
e. Cracking no correlation with size of bulge
f. Geometry of bulges
