Winterization Discussion Group

[4 drums cokerParticipant]

Winterization Discussion Group Notes
10/26/12
Facilitated by Marshall Douglas, CEDA

• Freeze protection of decoking equipment
• Raise drill string to max height
• Ensure drain successful
• Blow air, possibly with methanol, into the Kelly hose and drill string
• Continuously rotate the drill stem drive
• Hoardings and roughnecks commonly used
• If >3 sides, must consider as a confined space and use continuous gas monitoring, rigrat
• Typically done around pumps, finfans, and maintenance jobs (pigging)
• One site is discontinuing hoarding for 2012-13 winter….
• Cutting water tank gooseneck should be very large, 24”, to prevent freeze up and sucking in the tank
• Blowdown finfans freeze prevention
• Automated steam injection upstream of inlets.  TC based on finfan outlet temp.
• Routine operator round to check louvers, temperature controls, and roughnecks required
• Hoarding sheets reused from year to year, rolled down from fans to deck around the outside.
• Cold air coming down through the finfans can cause freezing.  Monitor temps in the plenum and take corrective actions.
• Entire blowdown system has a nitrogen blanket system to purge the entire blowdown during extended outages.
• Consider the use of minimum flow recirculation on the blowdown sour water to prevent freeze up.  Will not prevent freezing of the rundown piping.
• Water in reflux (1-2%) can freeze during outages, drain during maintenance
• Methanol added to the frozen line.  Freed in a few hours.
• During restart, cut off all steam purges to structure valves and other purged valves until the unit circulation temperature is >325C.  Net steam purge calculated to be 20ton/hr
• Except the switch valve

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