MARINE PURIFIER

1. INTRODUCTION

A marine purifier is a critical piece of equipment on board ships used to remove water and solid impurities from fuel oil and lubricating oil. Clean oil is essential for the efficient and reliable operation of marine engines. The purifier ensures that only clean oil enters the engine, thus protecting components from wear and reducing maintenance needs,

2. Why Purification is Necessary

Marine fuels, especially heavy fuel oil (HFO), often contain:

  • Water (condensation or contamination)
  • Solid particles (like rust, sand, or carbon deposits)
  • Sludge and chemical impurities

If not removed, these contaminants can:

  • Damage engine components (injectors, piston rings, bearings)
  • Reduce combustion efficiency
  • Increase wear and tear
  • Cause operational failures

3. Principle of Operation

Marine purifiers work on the centrifugal separation principle. When contaminated oil is rotated at high speed, heavier particles (like water and solids) move outward due to centrifugal force, and lighter oil collects near the center.

There are two main operating modes:

  • Purifier Mode (for separating oil, water, and solids)
  • Clarifier Mode (for removing solids only, no water separation)

4. Main Components

1.  Bowl Assembly – The heart of the purifier where separation occurs.

2.  Disc Stack – Series of conical discs that increase the separation surface area.

3.  Inlet and Outlet Ports – For contaminated oil in and clean oil out.

4.  Sludge Outlet – For discharging collected solids.

5.  Water Seal Line – Prevents oil from escaping with water.

6.  Drive Motor – Powers the bowl’s rotation.

7.  Control System – Regulates flow, temperature, and operation cycles.

 

Feature

Purifier

Clarifier

Function

Separates oil, water, and solids

Removes solids only

Water Seal Needed

Yes

No

Disc Stack

Has a gravity disc

Has a blind disc (no water outlet)

6. Types of Marine Purifiers

  • Manual Clean Purifier – Requires manual disassembly for cleaning.
  • Self-cleaning / Automatic Purifier – Uses a hydraulic or pneumatic system to eject sludge automatically, improving efficiency.

7. Operating Parameters

  • Oil Temperature: Typically 85–98°C (improves separation)
  • Flow Rate: Adjusted to match engine requirements
  • Backpressure & Gravity Disc: Adjusted according to oil type (viscosity and density)

8. Maintenance and Troubleshooting

·        Regular Checks: Temperature, pressure, vibration

·        Sludge Removal: Manual or automatic depending on design

·        Common Issues:

o   Loss of separation (wrong gravity disc)

o   Bowl vibration (imbalance)

o   Leakage (seal failure)

o   Sludge build-up (irregular cleaning)

9. Safety Considerations

  • Ensure proper bowl locking before starting
  • Do not open while rotating
  • Follow manufacturer’s SOPs during maintenance
  • Use PPE (gloves, goggles, aprons) during cleaning

10. Conclusion

The marine purifier plays a vital role in ensuring the longevity and performance of shipboard engines. By effectively removing contaminants from fuel and lubricating oil, it safeguards critical machinery, reduces operating costs, and enhances overall efficiency.

 

 

🔹 1. What is the principle of a marine purifier?

Answer:
A marine purifier works on the principle of centrifugal separation. When oil is rotated at high speed, heavier particles like water and dirt are thrown outward, and lighter clean oil stays in the center and flows out.

🔹 2. What is the difference between a purifier and a clarifier?

Answer:

  • A purifier removes oil, water, and solid impurities.
  • A clarifier removes only solid impurities (no water separation).
  • A purifier uses a gravity disc; a clarifier uses a blind disc.

🔹 3. What is the function of the gravity disc?

Answer:
The gravity disc controls the interface level between oil and water in the purifier. The correct size of the gravity disc ensures proper separation of water and oil.

🔹 4. What is the function of the sealing water?

Answer:
Sealing water forms a water seal at the outer edge of the bowl to prevent oil from escaping with water and helps maintain the oil-water interface.

🔹 5. What is the purpose of heating the oil before purification?

Answer:
Heating the oil reduces its viscosity, which makes it easier to separate water and dirt from the oil. Typical temperature: 85°C to 98°C.

🔹 6. Why is back pressure important in a purifier?

Answer:
Back pressure helps maintain steady flow and correct interface position in the bowl. If back pressure is too high or low, separation may fail.

🔹 7. What will happen if the gravity disc size is too small?

Answer:
If the gravity disc is too small, the oil-water interface will move inward, and clean oil may get discharged with water, causing oil loss.

🔹 8. What are the types of bowls used in purifiers?

Answer:

  • Solid bowl (manual cleaning)
  • Self-cleaning bowl (automatic sludge discharge using water or air pressure)

🔹 9. What maintenance is done on purifiers?

Answer:

  • Cleaning the bowl and disc stack
  • Checking the motor and bearings
  • Inspecting sealing ring and sludge chamber
  • Checking for vibration and noise

🔹 10. What safety precautions are taken while operating the purifier?

Answer:

  • Do not open the bowl while spinning
  • Use proper PPE (gloves, goggles)
  • Lock the bowl properly
  • Follow start/stop procedures as per manual

 

Troubleshooting for Marine Purifier (Trouble Shooting)

These are common problems, possible causes, and simple solutions for purifiers on ships.

 1. Purifier not separating properly (oil and water mixing)

Possible Causes:

  • Wrong gravity disc size
  • No sealing water or seal lost
  • Oil temperature too low
  • Wrong back pressure

Solutions:

  • Use correct gravity disc
  • Check sealing water supply
  • Increase oil temperature (85–98°C)
  • Adjust back pressure

🔧 2. Water comes out with clean oil

Possible Causes:

  • Gravity disc too small
  • Interface moved inward
  • Wrong purifier mode

Solutions:

  • Use larger gravity disc
  • Check oil type and density
  • Confirm it is running in purifier mode

🔧 3. Oil comes out with water (oil loss in sludge)

Possible Causes:

  • Gravity disc too large
  • Water seal lost
  • Sludge discharge frequency too low

Solutions:

  • Use smaller gravity disc
  • Restore sealing water
  • Increase discharge frequency

🔧 4. Bowl not rotating or rotating slowly

Possible Causes:

  • Motor problem
  • Brake not releasing
  • Bowl stuck due to sludge
  • Bearing failure

Solutions:

  • Check and test motor
  • Check brake system
  • Clean bowl and remove sludge
  • Check and replace bearings if needed

🔧 5. Excessive vibration

Possible Causes:

  • Bowl unbalanced due to sludge
  • Improper assembly after cleaning
  • Worn bearings

Solutions:

  • Clean bowl and disc stack
  • Reassemble correctly
  • Check and replace bearings

🔧 6. High sludge content or frequent blockages

Possible Causes:

  • Very dirty oil
  • Long operation without discharge
  • Poor pre-filtration

Solutions:

  • Improve pre-filtration (use settling tanks)
  • Increase discharge frequency
  • Clean purifier regularly

🔧 7. Sealing water not coming

Possible Causes:

  • Solenoid valve not working
  • Blocked sealing water line
  • No water in tank

Solutions:

  • Check solenoid valve and electrical supply
  • Clean water line
  • Fill sealing water tank

🔧 8. Purifier trips on overload

Possible Causes:

  • Motor overloaded due to stuck bowl
  • Bearing damage
  • Too much sludge in bowl

Solutions:

  • Manually rotate bowl and clean it
  • Check motor current
  • Inspect and clean bearings

Extra Tip:

Always refer to maker’s manual for correct gravity disc size, oil flow rate, and maintenance schedule

 

SOLAS Regulations for Marine Purifier Systems

While SOLAS doesn't directly mention "purifier" as a standalone topic, it lays down indirect but critical safety and construction requirements for all fuel oil and lubricating oil systems — and purifiers are an integral part of those.

These are covered mainly under:

✅ SOLAS Chapter II-1 – Construction – Machinery Installations
✅ SOLAS Chapter II-2 – Fire Protection, Detection and Extinction

 Key SOLAS Requirements Related to Purifiers

 1. Purifier Location & Arrangement

SOLAS II-2 Reg. 4.2.2.6 & Reg. 4.2.2.7

  • Fuel oil purifiers must be located in a separate space or a designated area within the engine room.
  • If purifiers handle heated fuel oils (>60°C), the system must be protected against fire.
  • The purifier room must be fitted with:
    • Fire detection system
    • Fixed fire extinguishing system (e.g., CO₂ or foam)

 2. Fuel Oil Piping Requirements

SOLAS II-2 Reg. 4.2.2.1 and Reg. 4.2.2.2

  • Pipes from purifiers must be made of steel or equivalent materials.
  • Must be arranged to minimize leakage onto hot surfaces.
  • Quick closing valves must be fitted on inlet/outlet lines at purifier tank.

 3. Drip Trays and Overflow Protection

Required to contain any oil leakage.

  • SOLAS mandates the use of drip trays under oil-handling equipment, including purifiers.
  • High-level alarms or overflow alarms for sludge tanks are recommended.

 4. Hot Surface Protection

SOLAS II-2 Reg. 15.2.10

  • Heated purifier bowls, piping, or heaters must be shielded to prevent oil spray contact on hot surfaces.
  • Surface temperatures in oil systems must not exceed 220°C.

 5. Emergency Stops

  • Purifier must stop automatically in case of:
    • High vibration
    • High bearing temperature
    • Low oil pressure
    • High sludge level
  • Manual emergency stop switch must be available.

 6. Sludge Tank Arrangements

  • Sludge tank connected to purifiers must be:
    • Ventilated
    • Overflow-protected
    • Fitted with level indicators
    • Periodically emptied (recorded in Oil Record Book - Part I)

 7. Fire Protection Systems

  • Purifier room must have:
    • Smoke or flame detector
    • Fixed CO₂ or foam fire extinguishing system
  • Portable foam or dry powder extinguishers must be nearby

 Documentation & Logs Required

  • Oil Record Book entries (sludge discharge, tank cleaning)
  • Purifier maintenance log
  • Vibration and bearing temperature logs (for auto shutoff monitoring)
  • Class-approved manuals and certificates

 Oral Exam Tip

Q: What is the SOLAS requirement for oil purifier fire safety?
✅ Answer: If the purifier handles heated oil, it must be located in a protected space with fire detection, fixed fire extinguishing system, drip trays, and shielding of hot surfaces to prevent ignition from oil spray

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