There is a grossly oversized pipeline carrying LP oil. SLUG problem in the pipeline is observed, which is preventing the owners from sweating asset limits. The original pipeline is 14" size. It is observed that (theoretically) if the diameter of riser (upper) is reduced to 10" pipe, then SLUG is grossly suppressed. Steady as well as Dynamic Simulations has been done to establish that.

Has anybody got experience in inserting lower dia pipe (say 10") in bigger dia pipe (say 14") using sleeves? Is it possible? Otherwise, suggest any other way to decrease void fraction in pipeline? Short shutdown and no hot work in pipeline will be most preferred.

Thanks in advance