MMPX Separation System

System Description

Printed Mar 1998 Book No. 1810028-02 V4

Alfa Laval Marine & Power

Contents

1	Scope	1
2	System Overview	3
2.1	System Layout	4
2.2	The Oil Flow	6
3	The MMPX Process	7
3.1	Purifying	7
3.2	Clarifying	9
3.3	Definition of Terms	10

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1 Scope

The MMPX separation systems are designed for cleaning of lubricating and fuel oils in marine and power applications and can handle the following types of oil:

• distillate

• marine diesel oil

• intermediate fuel oil

• heavy fuel oil with a maximum viscosity of 600 cSt

• detergent lubricating oil

• R&O lubricating oil

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1 Scope

MMPX System Description

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2 System Overview

In the MMPX process, heated oil is fed through the MMPX separator to clean the oil from solid particles and water.

An MMPX system comprises:

• An MMPX separator.

• Ancillary equipment including a control unit.

• Optional equipment such as an oil feed pump and an oil heating system.

The MMPX separating systems can be operated as single, parallel or serial systems.

An MMPX separator operates as a purifier or as a clarifier.

When operating as a purifier, cleaned oil leaves the separator through the oil outlet, separated water leaves through the water outlet, and sludge accumulates at the periphery of the separator bowl.

When operating as a clarifier, cleaned oil leaves the separator through the oil outlet while separated water and sludge accumulate at the periphery of the separator bowl.

In both cases, the control unit initiates a sludge discharge at preset intervals.

Sludge and water are then discharged through sludge ports at the periphery of the bowl and collected in an intermediate tank or a sludge tank.

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2 System Overview

MMPX System Description

2.1 System Layout

The MMPX system layout is illustrated by the following symbol diagram.

P00022RA

The MMPX system

The inlet and outlet arrows indicate the following:

• A Unprocessed oil inlet

• B Cleaned oil outlet C Oil recirculation

• D Water inlet

• E Sludge outlet

Item	Symbol	Designation	Function
1		Displacement pump	Feeds unprocessed oil to the separator.
2		Heater	Heats unprocessed oil to separation temperature.

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MMPX System Description

2 System Overview

Item	Symbol	Designation	Function
3		Pneumatically controlled change over valve	Leads the unprocessed oil to the separator or back to the tank (recirculation).
4		Separator	Cleans the oil by removing water and solid particles.
5		High pressure switch (For system without intermediate tank)	Senses high pressure in the oil outlet.
6		Low pressure switch	Senses low pressure in the oil outlet.
7		Pressure gauge	Displays the pressure in the oil outlet.
8		Manually controlled regulating valve	Regulates the clean oil back pressure.
9		Solenoid valve block, water	Distributes separator opening and closing water, water seal water, and displacement water.
10		Control unit	Supervises the separator system.

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2 System Overview

MMPX System Description

2.2 The Oil Flow

The unprocessed oil is fed by a positive displacement pump, operating at a constant flow. Depending on the oil type, the oil may need to be heated.

After the heater the change over valve directs the oil to the separator. The separated oil passes the manually operated back-pressure regulating valve to the receiving tank.

The oil can also be directed back to the tank, bypassing the separator. This is the case when the oil temperature is outside the preset range, during separator start and stop procedures, and during alarm conditions.

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3 The MMPX Process

The terms used in this process description are explained in section ‘‘3.3 Definition of Terms’’ on page 10.

For information about parallel and serial systems, see the “Installation Instructions” for the relevant MMPX system.

3.1 Purifying

When the MMPX separator is used as a purifier, a water seal is added to the separator bowl through the water inlet.

The separator is equipped with a gravity disc, chosen according to factors as oil temperature, density, and feed rate. This choice decides the position of the interface between oil and water seal.

The gravity disc leaves the water outlet from the bowl open.

Process Cycle

1. A specific amount of water is added to the separator bowl to form a water seal.

2. The feeding of unprocessed oil to the centre of the separator bowl starts.

3. During the separation process sludge and water accumulate at the periphery of the separator bowl. Cleaned oil is fed from the separator by the integrated paring disc. Excessive water leaves the bowl through the water outlet to the sludge tank.

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