Vibration issue on Compressor in a Nitric Acid Plant (Part 2)
Abstract
“Part 1 of the case history for this return to service follows on from the 2021 ATPS “ presentation which covered off the Expander related issue (labyrinth seal rubs) preventing the NAP 2 plant from successfully re starting ..“Part 2 covers off the machinery issues encountered during the following twelve month period of operation. The NAP 2 PAC was completely overhauled in March/April 2019 during a scheduled turn around period, conducted every 5 years, inclusive of a motor rotor replacement, step up gearbox overhaul, a new air end compressor installation as well as hot gas expander thrust bearing and thrust collar replacements/repairs. Additionally, the expander seals were replaced with like for like but tighter clearance carbon seals, the entire drive train was re aligned and a new anti surge valve was installed. During bi monthly remote diagnostics review as part of an SSA agreement 6 x annual remote diagnostic reviews of all steady state and transient vibration data) it was verified that the NAP 2 PAC would occasionally trip off line due to high compressor 1 st stage direct ( 1 x synchronous vibration during steady state operation Diagnosis verified compressor 1 st stage rub ( events during steady state operation as well as occasional stall and/or surge events due to anti surge system issues during shutdowns Additionally, a prominent 1 st stage 3 x reverse vibration component manifested post the turn around with increasing amplitudes up until the OEM attended site to perform a repair in (February 2020
Description
Case StudiesCollections
Citation
Wright, Gary; Peton, Nicolas; Drygin, Sergey; Yu, John; Davies, Dave (2022). Vibration issue on Compressor in a Nitric Acid Plant (Part 2). Turbomachinery Laboratory, Texas A&M Engineering Experiment Station. Available electronically from https : / /hdl .handle .net /1969 .1 /197019.