Home › Forums › Conferences › 2012 Canada › Winterization Discussion Group This topic contains 0 replies, has 1 voice, and was last updated by 4 drums coker 9 years, 6 months ago. Author Posts October 29, 2012 at 1:13 pm #1791 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 Author Posts You must be logged in to reply to this topic.