How often is turbine oil filtered?

The frequency of filtration of turbine oil (steam turbine oil) depends on factors such as oil status, equipment operating conditions, and degree of contamination. It is usually necessary to combine regular testing and online monitoring to formulate a reasonable filtration or purification cycle. The following are specific suggestions:

1. Conventional filtration frequency reference

| Operating conditions | Recommended filtration frequency | Description |

|---------------------------------------|-------------------------------------------------|-------------------------------------------------------------------------|

| After new oil injection or overhaul  | Filter within 24~48 hours of first operation | Remove residual impurities in the pipeline to ensure that the oil cleanliness meets the standard (such as NAS level 6 or ISO 4406 16/14/11). |

| Normal operation (no abnormality) | Filter once every 3~6 months | Regular maintenance to prevent oxidation products and trace moisture accumulation. |

| High humidity or polluted environment | Once a month or online continuous filtration | Humid environment is prone to moisture intrusion, and dehydration treatment needs to be strengthened (such as with a vacuum oil filter). |

| When oil contamination exceeds the standard | Filter immediately until it reaches the standard | Treatment is required when particulate matter (such as NAS level 8 or above), moisture (>500ppm) or acid value (>0.2mg KOH/g) exceeds the standard. |

2. Key indicators trigger filtration

The timing of turbine oil filtration should be based on laboratory testing or online sensor data:

- Particle contamination: NAS 1638 level ≥7 or ISO 4406 ≥18/16/13.

- Moisture content: Dehydration is required when it is >300ppm (ppm) (target <100ppm).

- Acid value: Filtration or oil change is required when it is >0.2mg KOH/g (may be accompanied by antioxidant supplementation).

- Color/odor: The oil is dark brown or has a burnt smell, indicating severe oxidation and needs to be filtered or regenerated.

3. Recommended filtration method

ｓｅｌｅｃｔ equipment according to the type of pollution:

- Particles: Use precision oil filter (β≥200, filtration accuracy 1~5μm).

- Water: Use a vacuum oil filter (can dehydrate to less than 50 ppm) or a coalescing separator.

- Comprehensive pollution: Choose a centrifugal oil filter or a multi-stage filtration system (remove impurities first and then dehydrate).

4. Measures to extend the filtration cycle

- Install online filter: Set up bypass filtration in the oil tank circulation pipeline to reduce the frequency of offline filtration.

- Control pollution sources: Keep the oil tank sealed and the breathing valve desiccant effective to prevent dust and moisture from entering.

- Regular monitoring: Take samples every 1~3 months to test the physical and chemical indicators of the oil.

5. Precautions

- Avoid excessive filtration: Frequent filtration may destroy the stability of additives in the oil (such as anti-wear agents, antioxidants).

- Record data: Establish an oil status ledger and analyze pollution trends to optimize maintenance plans.

- Synchronize with equipment maintenance: Perform comprehensive cleaning and filtration of the oil system when the unit is shut down for maintenance.