【Haichuan’s Insights from Other Sources】Qilu Second Chemical Plant: Eliminating Risks Associated with the Auxiliary Oil Pump in Hydrogenation Cycle Compressors to Ensure Long-Term Operational Stability

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Qilu No. 2 Fertilizer Plant: Eliminating Equipment Hazards to Ensure Long-Term Stability 2018-12-29 Source: Petrochemical News. Qilu Petrochemical’s Second Fertilizer Plant has strengthened the management of equipment operation, focusing on ensuring the safe and stable operation of equipment over the long term. By aiming to create \"standardized pump areas\" and build \"regional brands\", it implements the requirements related to \"three basics\" and carries out inspections and rectifications to enhance the intrinsic safety of the equipment. Recently, Erhua has successfully addressed the safety risk associated with the inability to use a backup oil pump for the hydrogenation cycle compressor in the octanol plant, through innovation and improvements to equipment technology. This has laid the foundation for the safe, stable, and long-term operation of the plant. Since the operation of the octanol unit’s hydrogenation cycle compressor began, the auxiliary oil pump has been unable to shut down on its own for standby mode, thus becoming a persistent problem that hinders the unit’s long-term operation. A failure in the oil system can cause severe damage to the unit. To address this issue, German experts visited the factory three times to find a solution, but ultimately concluded that the auxiliary oil pump could not be made to shut down automatically. “Leveraging our advantages in equipment integration, we are confident that we can bring it to a stop! ”Sun Yu, the newly appointed deputy director of the factory, is determined to eliminate potential hazards, and has made the stable operation of the large-scale machinery units a key focus for improvement, resolutely taking action against any \"unstable factors\". Early exploration helps identify the cause. “After several attempts to stop the pump manually, we found that the automatic start-up of the auxiliary pump is closely related to unstable oil pressure. ”Li Xin, the deputy head of the Motorization Department, recorded the relevant data in a notebook. Through comparative analysis, it was found that after the auxiliary pump stopped, the main oil pump could not deliver sufficient flow, resulting in a drop in oil pressure and vibration in the oil pipelines; when these conditions were met, the standby pump started and stopped frequently. “Once the problem is found, the solution is available! ”Li Xin marked the key data. Prescribe the right remedy for the specific condition. “We, in conjunction with the mechanical, electrical, and instrumentation teams, organized two technical troubleshooting sessions to develop a detailed operation plan for the standby pumps that were out of service. ”Chen Keming, a specialist from the Mobile Equipment Team of the Motorization Section, presented a technical plan filled on three pages. To ensure sufficient oil supply from the main oil pump, the plant deviated from the original design and adopted a \"increase speed and pressure\" strategy, which involves raising the rotation speed within the normal operating range of the compressor in order to increase the oil pressure in the main circuit. Once the oil pressure meets the requirements, stable switching becomes the key to stopping the pump. The factory’s specialists went to manufacturers of similar units for further inspections. After several investigations, it was decided to install accumulators in the lubrication system in order to eliminate pressure fluctuations in the oil network that occur when the standby pump stops. After multiple optimizations, the pump shutdown plan has been finalized. Identify the right moment to eradicate the source of the problem. On November 13th, the opportunity finally arrived. Taking the opportunity of the CT201 speed control valve maintenance, the plant divided its technical personnel into two teams: one team carried out the regular maintenance, while the other prepared to shut down the oil pump. Once the compressor was operating normally, the pump shutdown test officially began. After repeated adjustments, the factory combined actual production conditions with scientific principles to break conventions once again by revising the start-up and shutdown control parameters. With the full support of the monitoring instruments, the standby pump finally stopped making noise, and the persistent problem that affected the stable operation of the compressor was completely eliminated. (Yang Tao, Zhao Bing, He Hailong)