Operational Guide · Registers & Logbooks

# Purifiers and Separators (Fuel Oil / Lube Oil Purifiers)

The first line of defence against contaminated fuel and oil: why an incorrect purifier setting ripples through everything, from the main engine to the sludge balance.

purifiers separators fuel oil lube oil

## Operational Explanation

Centrifugal purifiers remove water and solid particulate from fuel and lubricating oil before use in main and auxiliary machinery. Inadequate purifier settings or maintenance not only expose machinery to damage risk, but also alter the sludge production balance, with knock-on effects on environmental management (see Sludge Management in the MARPOL Operations module).

Balancing separation effectiveness against sludge production is a technical trade-off requiring periodic adjustment, especially as the quality of fuel received in different bunkerings varies.

## Regulatory Reference

There is no single convention dedicated to purifier settings, but their correct management is functional to compliance with MARPOL Annex I (sludge balance, prevention of non-compliant discharges) and to protecting machinery according to manufacturer instructions.

## Scope of Application

Every ship fitted with centrifugal purifiers for fuel and lubricating oil, typically in the engine room.

## Procedure / How to Complete It

1. Adjust purifier throughput and temperature according to manufacturer specifications and the quality of fuel received in the last bunkering.
2. Periodically verify separation effectiveness through analysis of fuel/oil downstream of the purifier.
3. Monitor the resulting sludge production, checking its consistency with the expected monthly balance.
4. Perform periodic purifier maintenance (bowl cleaning, replacement of worn components) according to the maintenance plan.
5. Record every adjustment or maintenance intervention, especially after a significant change in fuel quality.

## Practical Example

Example of adjustment: after a bunkering with higher-density fuel than the previous one, the purifier is readjusted according to manufacturer tables, with separation effectiveness verified through a downstream sample before considering the operation complete.

## Real Cases

Damage to injectors and main engine components has in several cases been traced to a purifier setting not updated after a change in fuel quality, with particulate or residual water exceeding engine tolerances, even though the purifier was formally 'in operation'.

## Common Mistakes Mistake Library

Mistake | Consequence | How to avoid it
--- | --- | ---
Purifier setting not updated after a change in fuel quality | Reduced separation effectiveness, risk of machinery damage | Review the setting at every bunkering with characteristics significantly different from the previous one
No analytical verification of separation effectiveness, only visual inspection | Residual contamination not detected | Periodically verify with downstream analysis, not only visual inspection
Sludge production not monitored in relation to purifier setting | Inconsistencies in the monthly sludge balance, hard to justify in the event of a check | Systematically link sludge production monitoring to purifier settings

## PSC Observations

PSCOs do not typically verify the technical setting of purifiers directly, but its consequences (inconsistent sludge balance, Oil Record Book discrepancies) are among the most commonly checked environmental deficiencies.

## Operational Tips

- Update the purifier setting at every significant change in fuel quality, not only periodically by calendar.
- Verify separation effectiveness with downstream analysis, don't rely on visual inspection alone.
- Link sludge production monitoring to purifier settings to detect anomalies promptly.

## Checklist

- Purifier setting updated according to received fuel quality
- Separation effectiveness verified analytically
- Sludge production monitored and consistent with the expected balance
- Periodic maintenance (bowl cleaning, components) performed according to plan
- Adjustment/maintenance interventions recorded

## FAQ

How often should the purifier setting be reviewed?
There is no fixed interval set by a rule: good practice calls for a review at every bunkering with fuel characteristics significantly different from the previous one, in addition to periodic routine checks.
Is the sludge balance linked to purifier settings?
Yes: a more aggressive separation setting generally produces more sludge; unexplained variations in the monthly sludge balance can indicate a setting problem or an issue with the quality of fuel received.
Should purifiers be stopped during main engine maintenance?
It depends on the plant configuration: on many ships purifiers operate continuously regardless of engine status, to maintain fuel quality in service tanks; always check the specific instructions of the onboard installation.
🎬 Additional photos, videos and interactive diagrams for this topic will be available in a future version of the platform.

## Related Topics

Sludge Management Bunkering Operations

### Leave feedback

Help us improve the platform during the beta -- it takes thirty seconds.

How useful do you find the platform so far?
Comment (optional)
Sign me up for the newsletter
Role