One of the special things about the delayed coker in the refinery is that it is a fundamentally batch process that we keep running continuously by having many things in pairs. The cyclic operation presents itself in drum and blowdown line cracking issues. But pipe stress and bolting issues have been a struggle for anyone in the maintenance department at a turnaround (TAR) would know.
Turnaround intervals are getting longer, 2 years to 6+ now. Flanges are getting bigger, 12″ to 24″ with 600# or higher ratings. Therefore the potential for a bolt issue during turnaround is going up significantly. If you have ever worked a coker TAR, it is common on the radio to hear something like, “Get XYZ contractor out to the switch deck to cut out the bolts on the switch valve and add time to the critical path for the machining repair required.” Then I saw something sitting on a desk, I had never seen before….
It is called the Pop-Washer. More info can be found at their site (link here). You can’t help but fiddle with this neat piece of machined steel. But the amazing thing is when you twist it. The two pieces come together like a jigsaw puzzle, thus releasing the stress on the nut.
At Refcomm Galveston 2015, we will be hearing a case study from Blackhawk Engineered Products and Tesoro Golden Eagle about how these products helped prevent galling from giving them TAR scope extensions during their recent shutdown in 2014.