【2026 Ethylene Compression】Ethylene plant: “Excessive vibration in pyrolysis gas compressor””

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🔣 In an ethylene plant, the vibration of the pyrolysis gas compressor is above the specified limits (axis vibration exceeds 60μm, with a design limit of ≤45μm). How can the cause be identified? 🚩 Excessive compressor vibration is often caused by \"gas-liquid entrainment + rotor imbalance\"; a 3-step troubleshooting method can help identify the issue quickly and prevent damage to the unit. Troubleshooting steps: ① Check for liquid presence in the inlet pyrolysis gas stream (if the separator’s liquid level exceeds 80%, it may lead to liquid slugging and increased vibration) ； ②Analyze the vibration spectrum (a 1x frequency component accounting for over 70% indicates rotor imbalance, while a 2x frequency component exceeding 40% suggests misalignment of the couplings) ； ③Check the bearing temperature and the quality of the lubricating oil (if the oil temperature exceeds 55°C or the oil quality deteriorates, it will cause instability in the oil film). Case: The vibration level of the pyrolysis gas compressor in an ethylene plant reached 68 μm. Investigation revealed that high liquid level in the inlet separator was causing liquid entrainment; after reducing the liquid level, the vibration level dropped to 42 μm.