PALM OIL MANUFACTURING AND APPLICATION L1.1

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CHAP 1

Introduction to palm oil milling and refining

The chemistry of palm oil

Palm oil milling process

The purpose of palm oil refining

Development in the Malaysia palm oil refining

industry.

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Learning Outcomes 3

Student should be able to:

Explain the palm oil milling

process.

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THE

OIL

PA

LM F

RU

IT The fruit is made up of:

- Exocarp - skin - Mesocarp – palm oil and fibers - Endocarp - shell - Kernel – seed – oil & meal

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Palm Oil Milling Process

EXTRACTION

1. Bunch reception

2. Loading ramp

3. Sterilization

4. Threshing

8 Processes of palm oil production in mill:

5. Digestion

6. Oil Extraction

7. Clarification & purification

8. Nut and kernel station

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• Upon reception at the mill, the fruit is graded to ensure a high

standard of harvesting. Grade as follows:

(a) Fruit bunch < 10 loose fruitlets → unripe

(b) Fruit bunch ≥ 10 loose fruitlets → ripe

(c) Fruit bunch with excessive loose fruits detached → overripe

(d) Bunch with loose fruits completely detached → rotten

1. Bunch Reception

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Appropriate action will be

taken by mill and estate

management based on the

grading.

- Fruit will carried by

trucks to the loading

ramp.

1. Bunch Reception (con’t)

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Empty fruit bunch

2. LOADING RAMP

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Purpose of ramp operation:

- to ensure that old fruits are first taken out for processing, to avoid

accumulation of old fruit which otherwise will rot over a short period

- creating high FFA problem (should not exceed 5%).

2. LOADING RAMP (con’t)

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- Fruit from the hopper are loaded into the fruit cages waiting

underneath.

- Each cage hold about 2½ tons of fruit and these are pushed in a

train/locomotive to the sterilizer yard.

2. LOADING RAMP (con’t)

- The fruit arriving inside the cages are then charged into the sterilizer to be ‘cooked’ under saturated steam at 40 psig. - Quality of the cooked fruit is very important for subsequent process.

3. Sterilization 2. LOADING RAMP (con’t)

(a) Prevention of any further rise in FFA due to

enzyme action by inactivation of the lipolytic

enzymes

(b) To loosen fruit still attached to the bunch stalk

(c) Preparation of the fruit for subsequent

processing.

(d) Preconditioning of the nuts to minimize kernel

breakage during both processing and nut cracking

(e) Coagulations of the protein material and

hydrolysis of the other materials present in the

palm fruit.

3. Sterilization

Objective of sterilization:

3. Sterilization

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4. THRESHING

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Purpose: Threshing or stripping is done to separate the sterilized fruits from the sterilized bunch stalks.

- The sterilized fruit together with the fruit cage is lifted by a hoisting crane and then poured on to the threshing machine.

4. THRESHING (con’t)

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4. THRESHING (con’t)

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5. DIGESTION

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» PURPOSE: Process of reheat, where pericarp loosened from the nuts and prepared

for pressing.

» Digestion take place in steam heated vessels provided with stirring arms known as

digester or kettles.

» Temperature ≈ 100ºC, the arms stir and rub the fruit, loosening the pericarp from

the nuts and breaking open as many of the oil cells possible.

» The digester converts the stripped fruits into a homogeneous mash.

5. DIGESTION

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Palm oil is extracted by pressing in the screws press- consist of perforated cage in which runs a single or double screw

Press screw: tough and wear resistant steel; press cage: stainless steel.

The outlet end of perforated cage is restricted by a cone and it is this restriction of the discharge that creates a pressure in the cage.

Discharge from screw press:

crude palm oil liquor and matte of oily fibre and nuts

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Fibre and nuts: carried by the steam

jacketed conveyor

Crude oil: passed on to the

vibrating screens to be separated

from the accompanying solids.

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7. Clarification & Purification

Purpose:

- to give a clear stable product of

acceptable appearance. Water and

impurities must be removed.

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7. Clarification & Purification (con’t)

1 • The crude oil is diluted first with hot water to reduce its viscosity.

2 • The diluted crude oil is screened to remove any coarse fibrous

material which is returned to digester.

3 • The screened crude oil is heated (90-95°C) and pumped to the

continuous settling tank.

4 • Retention of the crude liquor in settling tank enables the oil to rise to

the surface and overflow continuously into a reception tank.

5 • Settled oil purified by centrifuging – reduce the dirt content to

0.01% or less

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8. Nut & Kernel Station

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Nuts are normally not processed for the oil content in the same mill. Separation of nuts from the accompanying fibre is done in depericarper station.

8. Nut & Kernel Station (con’t)

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Function of depericarper: • nut polishing • partial drying of fibre

transport of fibre to the boiler house

• grading out of oversize foreign material e.g wood, stones, metal bits and stalks

8. Nut & Kernel Station (con’t)

Application

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• Pressed fibres uses as fuel to the boiler.

• The separated shells are sent to the yard as fuel to the boiler whereas the kernels are then sorted in kernel silo dryer before final storage in the bulk kernel silo.

8. Nut & Kernel Station

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The purpose of palm oil refining

REFINING

EXTRACTION

Why refining?

• Water, insoluble impurities, free fatty acids, oxidation

product should be kept a minimum level.

• However, the refining treatment should retain as much

as possible the tocopherols and tocotrienols because

of their antioxidant effect to the product.

• Two methods of refining: physical or chemical refining.

Summary/Take Home Message 33

1. Bunch reception

2. Loading ramp

3. Sterilization

4. Threshing

8 Processes of palm oil production in mill:

5. Digestion

6. Oil Extraction

7. Clarification & purification

8. Nut and kernel station