Minimize Shaking Maximize Process Safety

摘要

Integrity of piping systems is critical for the safe and reliable Plant operations. Shaking or Vibration of piping systems pose potential threats to plant safety and integrity. In GASCO plants, vibrations were observed in some systems such as piping carrying two-phase flow, high pressure lines, piping associated with compressors / pumps, etc. Minimizing the pipe shaking to maximize the process safety through a systematic approach will result in economical, efficient, safe and time bound advantages. This paper presents GASCO's approach in resolving piping vibrations and mitigating the risks to plant operations. Studies were carried out to investigate the root cause and recommend required remedial measures. Walkthrough along the piping system was carried out to identify locations of high vibrations and to detect any mechanical abnormalities as first step. Process conditions were also verified for any upsets. This was followed by measurement of vibration parameters such as amplitudes, frequencies and accelerations. The data collected was analyzed and level of vibrations were classified as critical and non-critical based on recommended limits as per relevant industry standards. For the critical systems, detailed process studies / piping stress analysis were carried out by simulating actual piping vibration taking various excitation sources and as-built conditions into consideration. Theoretical results were compared with field data and were found to be consistent. In order to limit the vibrations within permissible values, necessary measures were recommended. Based on recommended modifications, revised piping stress analysis was carried out to ensure vibrations are within design limits. Implementation packages were prepared to execute the suggested remedial measures. Post-implementation vibration measurements were taken and observed to be comparable to design values and within permissible limits, thereby ensuring plant safety and integrity. Less attention paid to piping vibration during initial design phase, probably due to lack of clear and precise codes and standards, was found to be the main reason for piping vibrations. GASCO recognized the need for documenting the above best practices to address piping vibrations. The Guidelines are developed to identify/classify the severity of vibrations and the way forward to tackle the piping vibration issues which can be used by site personnel.