Start-up procedures and precautions for centrifugal pumps in cold seasons and low-temperature environments

In industrial sectors such as petrochemicals, natural gas transportation, and high-altitude cold regions, centrifugal pumps frequently encounter a range of severe challenges in low-temperature environments, including difficulty in starting up, material embrittlement, lubrication failure, seal leakage, and performance degradation. Improper operation can not only lead to serious damage to critical components (such as bearings, seals, and impellers) but may also trigger a chain reaction of production accidents, resulting in significant economic losses and safety risks. Therefore, going beyond conventional single protective measures and establishing a comprehensive technical system encompassing equipment structural design, environmental adaptability assessment, refined operation, and systemic risk management has become an urgent need to ensure production continuity under extreme operating conditions. This paper aims to elucidate the core content of this technical system systematically and, through theoretical analysis, parameterized standardization, and the provision of a complete and practical solution for the safe, reliable, and efficient operation of centrifugal pumps in low-temperature environments.

• Systematic Start-up Preparation Procedure for Centrifugal Pumps in Low Temperature Environments

Pre-start Checklist (24 hours prior)

Phase 1 (H-24 to H-12):

1. Ambient temperature recording (hourly)
2. Medium flowability test
3. Full-power operation of the heat tracing system
4. Low-temperature viscosity test of lubricating oil

Phase 2 (H-12 to H-4):

1. Pump body temperature uniformity check (temperature difference ≤ 15℃)
2. Sealing system airtightness test
3. Electrical insulation test (insulation resistance ≥ 100MΩ)
4. Instrument calibration (emphasis: pressure transmitter zero point)

Phase 3 (H-4 to H-1):

• Jogging test (3 times, 30-minute intervals)
• Minimum flow valve function test
• Emergency heating system standby confirmation
• Operator cold-weather gear check

Thermal balance control technology

Gradient temperature rise control

1. First stage: 5℃/h (to -10℃)
2. Second stage: 3℃/h (-10℃ to 0℃)
3. Third stage: 2℃/h (0℃ to operating temperature)

Hotspot monitoring deployment

Centrifugal pump precautions in cold seasons

Winter Centrifugal Pump Antifreeze Measures:

1. Draining Water: After shutdown, thoroughly drain all liquid from the pump body and pipelines, especially for pumps conveying water or easily freezing media. According to API 610, when the ambient temperature is below 0℃, stagnant liquid may cause pump body cracks due to freezing expansion.
2. Insulation and Heat Tracing: Install electric heating tape or insulation cotton on critical components (such as bearing housings and inlet/outlet pipelines) to maintain a temperature ≥5℃ (refer to GB/T 3215-2019). If the medium is a high-pour-point oil, ensure the pipeline heat tracing temperature is at least 10℃ above the pour point (e.g., diesel fuel needs to be maintained above -5℃).
3. Lubricating Oil Change: In winter, switch to low-temperature lubricating oil. A viscosity grade of ISO VG 32 or lower is recommended (suitable for -30℃ environments) to avoid starting difficulties due to excessively high viscosity.
4. Use Antifreeze as a Substitute: For short-term shutdowns, inject a low-freezing-point liquid (such as an aqueous solution of ethylene glycol, with a freezing point of -36°C at a 1:1 ratio). For long-term shutdowns, it is recommended to use anhydrous antifreeze oil (compliant with ISO VG32 standards).
5. Maintain Minimum Flow Rate: For continuously operating pumps, ensure the flow rate is ≥30% of the rated value (according to API 610) to prevent static water from freezing.
6. Ambient Temperature Monitoring: Install a temperature sensor and set an alarm threshold (emergency measures at -5°C). In northern regions, it is recommended to equip the pump with an automatic heating device.
7. Regular Maintenance and Inspection: Test the flexibility of the drain valve weekly to prevent rust and jamming. Conduct a thorough inspection of the insulation integrity before a cold snap.

Long-Term Shutdown and Restart Guidelines

1. If shut down for more than 7 days, drain the medium and inject antifreeze (such as ethylene glycol solution).
2. Before restarting, preheat to an ambient temperature difference of ≤20℃ to avoid thermal stress damage.

Emergency Handling

If the pump body is found to be frozen:

1. Do not start the pump directly to avoid impeller breakage.
2. Slowly pour warm water (≤60℃) to thaw the pump. Do not use open flame to thaw it.
3. After thawing, conduct an airtightness test (pressure 1.5 times the working pressure, hold for 30 minutes).

This paper systematically discusses a comprehensive technical solution for centrifugal pumps to cope with extreme low-temperature environments. Its core value lies in integrating discrete technical points into a logically rigorous and clearly operational systematic engineering method. It provides a theoretical basis and practical framework for enterprises to establish a long-term equipment safety management mechanism, and has important guiding significance for improving the inherent safety level of fluid transport systems in extremely cold and similarly harsh environments.