60" Slug Catcher
The Need & Challenge
A slug catcher is a large piping assembly designed to separate condensate from gasses in a pipeline. This particular slug catcher was made from 60" piping with a 1" wall thickness and consisted of 6 headers.
The saddles supporting each header had to be removed for refurbishment before being reinstalled but due to the extreme rigidity of the catcher assembly, all 6 headers had to be lifted simultaneously in order to provide the access. The reaction load produced by all 6 headers at once to a height of 1" was calculated to be 460,000 lbs which is significant.
Solution & Outcome
The entire header assembly was modelled to perform a pipe stress analysis in order to model the displacements applied during lifting. This provide accurate load calculations to ensure appropriately rated equipment was used and to ensure the catcher was over stressed during the lift.
The only viable solution was to use airbags lifting from crib stacks at 12 locations (2 locations per header with one on either side of the support).
All 12 locations had to be lifted simultaneously to provide sufficient force to lift the header. Once lifted, the header was blocked up to eliminate the suspended load making it safe for crews to work underneath. Additionally, only 1 saddle was removed at a time leaving 5 other saddles in place.