Shell Chemical's Deer Park Plant

摘要

Shell Chemical LP's OP-Ⅲ olefins unit, located in Deer Park, Texas, has a process gas train consisting of a 60,500 hp GE turbine driving three Elliott M-Line centrifugal compressors in series. Approximately 5.5 years after the last overhaul, the middle compressor developed large amplitude vibration that would come and go. A technical team was chartered to conduct a root-cause analysis of the vibrations without taking the machine off-line. The team theorized that the most probable cause of the vibration was a rub at the balance piston seal exacerbated by polymer build-up and thermal expansion. The vibration signature and other supporting data were consistent with the theory. Recommendations were made to increase the flow of wash oil, to change wash oil chemistry, and to limit discharge temperatures. Operation was able to continue with the vibration through 2004.