Working principle of purifier in ship

On a ship, a purifier is used to clean fuel oil or lubricating oil, removing impurities such as water, sludge, and solid particles to ensure the quality and performance of the oil. The working principle of a purifier on a ship relies on centrifugal separation, which uses the density difference between oil, water, and impurities to separate them under high centrifugal force. 

 Working Principle of a Purifier on a Ship:

1. Oil Intake and Heating:

   - The oil to be purified is first heated to reduce its viscosity, making the separation process more effective. Typically, fuel oil is heated to about 80-90°C, while lubricating oil may be heated to 60-70°C.

   - The heated oil is then fed into the purifier bowl through an inlet.

2. High-Speed Rotation and Centrifugal Separation:

   - The purifier's bowl rotates at a very high speed, generating centrifugal forces that can be several thousand times the force of gravity.

   - As the oil mixture spins, the heavier components (water, sludge, and solid particles) are thrown outward toward the bowl's outer wall, while the lighter component (clean oil) remains closer to the center.

3. Separation with Disc Stack:

   - Inside the rotating bowl, there is a stack of conical discs that provide a large surface area for separation. The discs are spaced closely together, and the oil mixture flows upward through these narrow spaces.

   - The centrifugal forces act on the mixture, causing the denser water and sludge to move outward toward the periphery of the bowl, while the lighter, cleaner oil moves toward the center.

4. Formation of Layers:

   - During the separation process, three distinct layers form:

     - Outer Layer: Composed of water and sludge, which are the heaviest components.

     - Middle Layer: Consisting of the separated clean oil, which is less dense than water.

     - Inner Layer: Closer to the center, consisting of any remaining trace impurities.

5. Discharge of Separated Phases:

   - Clean Oil Discharge: The cleaned oil is continuously discharged from the top of the purifier bowl through a clean oil outlet.

   - Water and Sludge Discharge: The separated water and sludge are either discharged continuously or at regular intervals through dedicated discharge ports, depending on whether the purifier is self-cleaning or requires manual cleaning.

   - Gravity Disc or Paring Disc (Optional): In some purifiers, a gravity disc helps control the interface position between the oil and water, ensuring effective separation. A paring disc may also be used to aid in the removal of separated water.

6. Control Mechanisms:

   - The purifier may use a variety of controls for optimal performance, including temperature regulation, flow rate control, and interface control. These help maintain efficient separation, especially when different types of oil are being processed.

 Types of Purifiers Used on Ships:

- Clarifier: Designed mainly to remove solid impurities from oil.

- Purifier: Used to remove both water and solid impurities from oil.

- Self-Cleaning Purifier: Features automatic sludge discharge, enabling continuous operation.

- Non-Self-Cleaning Purifier: Requires manual cleaning and periodic removal of accumulated sludge.

 Applications on Ships:

- Fuel Oil Purification: Removes water and contaminants from heavy fuel oil (HFO) and marine diesel oil (MDO) before entering the engine.

- Lubricating Oil Purification: Cleans lubricating oil to ensure the protection of engine components and enhance engine life.

The centrifugal purifier on a ship plays a vital role in maintaining the quality of fuel and lubricating oil, ensuring efficient engine operation and preventing damage caused by contaminants.