PALM OIL PALM OIL INDUSTRYINDUSTRY

CMT 573CHEMICAL

TECHNOLOGY

INTRODUCTIONINTRODUCTION-Oil palm belongs to the family ‘Arecaceae’- Three species namely :

IntroductionIntroduction• Cultivated mainly in Malaysia, Nigeria, Ivory

Coast, Papua New Guinea• 1917 – the first commercial planting took

place in Tennamaram Estate, Selangor• Potential to yield 4 – 6 tons oil/ha.year ,

whereas other oilseed crops like coconut gives 1.5 tons/ha., soybean, sunflower etc give only 400 – 600 kg/ha.year.

Oil Palm Plantations

Palm Oil Mill

Palm Oil refineries

Oleochemical industries

Oleochemical

• 90% of palm oil produced in M’sia is used in the food sector for edible products with an export income of RM 20 billion per year.

• Downstream activities :• Example : August 1999 , a Proton-PORIM

collaboration was signed to incorporated into Proton cars selective car components made using palm oil derivatives.

The Oil PalmThe Oil PalmThe oil palm is an erect monoecious plant Harvest commences 24 – 30 months after

plantingEach palm can produce between 8 – 15 fresh

fruit bunches (FFB) per year.Each FFB contains 1000 – 1300 fruitletsEach fruitlets consists of a fibrous mesocarp layer, the endocarp (shell) which contain the kernel.

The Oil PalmThe Oil PalmThe individual fruit, ranging from 6-20 gm,

are made up of an outer skin (exocarp), a pulp (mesocarp) containing the palm oil in a fibrous matrix, a central nut consisting a shell (endocarp), and the kernel.

Kernel

Mesocarp

Endocarp

Exocarp

The Oil PalmThe Oil PalmBased on the difference in fruit structure,

3 oil palm varieties have been identified.•Dura – having thick shell (2-8 mm) with low to

medium mesocarp content (35-55%). This is not commercially grown.

•Piscifera – characterized by a shell-less fruit & pea like kernel inside.

•Tenera – hybrid obtained from crosssing Dura (female) and Piscifera (male). Thin shell (0.5-4mm) & medium to high mesocarp content (60-95%). Widely cultivated type all over the world.

The Oil PalmThe Oil PalmFirst harvest starts after 24 – 30 months

after planting, continues at an interval 7-10 days throughout the palm’s economic life which vary from 25 – 30 years.

When a few ripe fruits are loose/fall off, the bunch is ready for harvesting.

Over ripe fruits give reduced quantity and quality of oil.

Characteristics of palm oilCharacteristics of palm oilPalm oil is a vegetable oils, is cholesterol

free.Semi solid at room temp.Melting point between 33°C - 39°CCPO is deep orange red color (high natural

carotenes)CPO rich source of carotenoids & vit E

(which confers naturally stability against oxidative deterioration)

Fractionation separates oil into liquid & solid fractions.

Palm oil can be fractioned into liquid (olein) & solid (stearin) components

Palm OleinPalm OleinLiquid fraction obtained by fractionation cpoPhysical characteristics – fully liquid in warm

climate & has a narrow range of glycerides.Widely use as a cooking oil, blending partner

(blended with groundnut oil), frying oilPopular - Good resistance to oxidation &

formation of breakdown products at frying temperature & longer shelf-life of finished products.

Palm StearinPalm StearinMore solid fraction obtained by

fractionation of palm oil after crystallization at controlled temperatures (thus co-product of palm olein).

Useful source of fully natural hard fat component for products such as shortening, pastry, bakery margerines.

There are other fractions eg. Various grade of double fractionated palm olein (superolein) & palm mid fractions.

Palm Kernel OilPalm Kernel OilObtained from the kernel.

The oil composition is very different from that of the palm oil.

Physical properties :◦In temp. climates, PKO is a sharp melting fat.◦Very suitable for confectionery & similar uses.

Palm Kernel OleinPalm Kernel OleinLiquid component of palm kernel oil

obtained from fractionation.

More solid fraction of palm kernel oil obtained from fractionation.

Widely used to substitute for the more expensive cocoa butter

Makes the best Cocoa Butter Substitute (CBS)

Palm Kernel StearinPalm Kernel Stearin

Palm Oil ExtractionPalm Oil ExtractionFresh Fruit

Bunches (FFB)

Sterilisation of FFB

Threshing & Stripping of Fruitlets

Oil Extraction (Screw Press)

Press Cake

Clarification & Purification

Depericarping

Nut Cracking

Winnowing & Drying

PALM KERNEL (PK)

CRUDE PALM OIL (CPO)

Palm Oil Mill Effluent (POME)

Effluent Treatment Plant (ETP)

Bunch ReceptionBunch ReceptionFFB are transported to the mills by road

truck/lorry or cages running on specialty built railway station.

Upon reception at the mills, the fruits are first graded to ensure high std harvesting.

FFB with < 10 looses fruitlets = unripeFFB with = 10 looses fruitlets = ripeFFB with excessive looses fruitlets = over ripeFFB with looses fruitlets completely detached =

rottenThe grading report will forwarded to mill &

estate mgt for further action. Once approval to proceed is received, the fruits will be carried by trucks to the loading ramp.

Loading rampLoading rampFFB delivered is unloaded directly into ramp

hopper with minimum handling.Fruits from the hopper are loaded into the

fruits cages waiting underneath. Each 2 ½ tones of fruits are pushed in a train by a locomotive to the sterilizer yard.

The procedure in the ramp operation is to ensure that old fruits taken out for processing.

Essential to avoid accumulation of old fruits which otherwise will rot over a short period & thus creating high FFA problem (should not exceed 5%).

SterilizationSterilization

The fruits arriving inside the cages are then charged into the sterilizer to be “cooked” under saturated steam at the gauge pressure of 40 psig.

This process is very important in extraction since much of the subsequent process depends on the quality of the cooked fruits.

SterilizationSterilization

The FFB must be allowed to heat & become cooked.

Time = depend the weight of bunches.

Problems due to Inefficient sterilization Problems due to Inefficient sterilization

ThreshingThreshing

Threshing / stripping is done to separate the sterilized fruits from the sterile bunch stalks.

After sterilization, the sterilized fruit in the cages poured on the threshing machine.

Threshing machine consist of 2 parts:◦Thresher hopper / feeder ◦Thresher drum – rotary cylinder

As the action of rotation repeats several time, the fruits will drop out.

DigestionDigestion

The sterilized fruit must be reheated & the pericarp loosened from the nut.

Carried out in steam heated vessels provided with stirring arms (digesters/kettles).

Within temperature close to 100°C, the arm stir & rub the nuts (breaking open as many of the oil cells as possible)

The digester converts the stripped fruits into a homogeneous mash.

Oil ExtractionOil ExtractionPalm oil is extracted by pressing in the screw

press.A screw press consist essentially of a

perforated cage runs as a single or double screw.

The outlet end of the perforated cage is restricted by a cone.

The pressing of the digested mesh is done with minimum nut breakage.

The discharge from the screw consists of CPO liquor and a matte of oily fibre and nuts.

Clarification & PurificationClarification & PurificationCPO contains varying amount of water &

impurities (soluble & insoluble vegetables matter)

Composition of CPO : oil 66%, water 24% and the remaining is lumped (non-oily solids)

To give clear product, water & impurities must be removed.

This is carried out in the clarification process.Water removed by settling/centrifuging Used gravity settling system or direct

process

Clarification & PurificationClarification & PurificationFirst, the crude oil is diluted with hot water (to

reduce viscosity)Then, the crude oil is screened (to remove

course fibrous materials)The screened crude oil is then reheated to

90°C-95°C & then pumped to settling tank.The retention of the crude liquor in this tank

enables the oil to rise to the surface & overflow continuously to the RECEPTION TANK.

The settled oil is further purified by centrifuging (reduces dirt content to 0.01%)

Clarification & PurificationClarification & PurificationThe underflow from the continuous tank

= sludge (containing some oil which can be recovered by centrifuging)

Sludge discharged to the effluent treatment plant (POME)

At POME, anaerobic digestion produces methane which can be used as energy.

Nut & Kernel StationNut & Kernel StationThe nuts need to separate the shell from the

kernel.Before this is done, separation of the nuts

from the accompanying fibre is done in the depericarper station.

Function of depericarper = nut polishing, partial drying of the fibre, transport of the fibre to the boiler house, grading the size of foreign material.

The nuts will dry (60-77°C) before transported to nut cracking machine.

The separated shells sent to the yard as fuel.

Refining of the crude palm oilRefining of the crude palm oilObjective :-

to meet industry’s standards

Refining process should retain as much as possible the tocopherols and tocotrienols because of their antioxidant effect on the product.

purpose of refining process are to purpose of refining process are to removes:removes:

CPO Storage The initial temperature of CPO is at 40 – 60°C.

Degumming CPO react with phosphoric acid to precipitate the gums (Phosphatides). Operating temperature 90-130°C.

Degumming CPO

BleachingDegumming CPO react with bleaching earth (activated earth/Fuller earth) in order to removes undesirable impurities (pigments /trace metals / oxidation product) occur in sluury tank at 100-130°C for 30 minutes.

Bleached Palm Oil

FiltrationTrap filter / Niagara filter to filtrate bleaching earth particle oil

Pretreated oil storageTemporary storage (pump into buffer tank) before further processing

Steam refiningdeacidification and deodorization – removal of residue FFA, aldehydes and ketones. The deodorization process is a high temp., high vacuum & steam distillation process by using deodorizer. The hot RBDPO (250-280°C) as bottom product.

Polishing

Cooling

Edible Oil Storage

To prevent the earth traces from reaching the product tank. Temperature 120-140°C

storage with temperature 50 – 80°C.

Physical Refining Method

Flow Chart of Chemical Flow Chart of Chemical MethodMethod

Crude Oil Storage

Degumming Neutralization Water Washing

Drying

BleachingFiltrationPretreated or

neutralized and bleached storage

Deodorization

Polishing Cooling Edible Oil Storage

GENERAL PALM OIL REFINERYGENERAL PALM OIL REFINERY Degumming

◦ Removal of gums containing calcium and magnesium, which is found in the oil after refining, give the oil an inferior quality and therefore a shorter shelf-life.

◦ concentrated phosphoric acid 0.1% by weight is sufficient to remove a significant amount of the phosphatides and about 25 ppm of soap in the washed oil.

GENERAL PALM OIL REFINERYGENERAL PALM OIL REFINERY Neutralisation

The oil is neutralized by an alkali (NaOH) The resulting soap stock is separated from the

oil by centrifuging & washing with water. Any soap retained in the washed oil is removed

by adding citric or phosphoric acid to the final wash prior to drying of the oil.

GENERAL PALM OIL REFINERYGENERAL PALM OIL REFINERY

Drying◦ When the oil is discharged from the water

washing centrifuge is normally contains about 0.2% moisture.

◦ Such moisture level causes a rise in the FFA due to autocatalytic hydrolysis

◦ Therefore, the oil has to dried in a vacuum dryer to reduce the moisture content < 0.006% before the oil is transferred for bleaching.

Bleaching and filtration of palm oil◦ Bleaching is carried out by contacting with

adsorbent clay or carbon in the absence of oxygen (otherwise the activated clay may act as a catalyst for oxidation if oxygen is present).

◦ Process carried out under steam/ nitrogen blanket (to ensure absolutely no oxygen is present) usually on plant scale, under weight of the oil.

◦ The temperature range 80-180 °C. ◦ At the higher temperature, the adsorption effects

are better.◦ Once bleaching is complete, the oil is then pumped

through a filter and recycle until a filter cake has been formed on the elements and only then transferred to the continuous

Deodorization and polishingDeodorization and polishing◦ The process is done to reduce the oil to odourless

& tasteless fats and oils by remove the relatively volatile odiferous & flavoured substances (aldehydes, ketones & FFA)

◦ Deodorization = steam distillation under vacuum. The process does not reduce trace metals or phosphatide levels.

◦ If any soap is present, high losses will be encountered due to foaming in the deodorizer. When the oil is fully deodorized, it is cooled down to a temperature of about 55°C before being pumped through a polishing filter giving the finished oil its final sparkle.

FractionationFractionation◦ Fats & oils are mixture of triglycerides,

(b’coz different fatty acids compositions) the melting points spanning the range below -30°C to above, each having its own melting point.

◦ Fractionation (thermo mechanical) is :the process used to separate the lower melting point triglycerides from the higher melting point triglycerides (i.e. based on the difference in melting point)

Since distillation is unsuitable for the triglycerides mixtures because of their low vapour pressure & relatively low stability at higher temperatures……

the triglyceride composition of the oil is crystallized by controlled cooling followed by separation to yield a liquid ~ 30 – 40 % (olein, premium product) and a solid 60 – 70% (stearin phase).

Fractionation Plant Description

FractionationFractionationThere are 3 methods used commercially for

fractionation of palm oil which:

a) Dry process (dry fractionation)

b) Detergent process

c) Solvent process

Schematic diagram of crystallization process.Schematic diagram of crystallization process.

Dry ProcessDry ProcessThe oil is crystallized & separation is

effected by filtration. The oil is first heated to 70-75 °C so as to

melt all crystal nuclei and then passes to a crystallizer.

Crystallization proceeds by initially cooling to 45°C in about 45 minutes and then further cooling to 18 – 20 °C about 4-8 hours before being pumped to the filter

Filtering on membrane press filter (or Rotary Drum Vacuum filter) to separate the solid/liquid fractions.

Dry ProcessDry ProcessPalm Oil → Homo tank (heating)

Crystallizer (Cooling) 15 rpm – 5 rpm

Normal Fast Loading Loading

(Cooling from 60-21°C to produce cooking oil IV=56)Slow cooling for 4 hours to 24°C – cloud point = 10Slow cooling for 4.5 hours to 21° -- cloud point = 8

Pump by pipeline into filter press machine (4-6 bar)(the ↑ P, the ↑ olein produced)

Dry ProcessDry ProcessMain features & advantages of dry fractionation

◦Combines all operations, and monitors from a fully automated centralized control station.

◦Easy to operate, requires minimum supervision.

◦Good flexibility. Wide range of applications possible

◦Feedstock can be crude, semi refined or fully refined palm oil.

◦Suitable for both single or double fractionation.

Dry ProcessDry ProcessMain features & advantages of dry

fractionation ◦Minimum operating costs.

Low utility consumption Low maintenance costs No oil losses No pollution problem

◦Product quality Good crystallization repeatability, yielding consistent product quality.

High olein yields Low olein cloud point, with improved cold stability, cloud point as low as 2°C with iodine value of 65 can be obtained

Detergent ProcessDetergent Process◦ The oil is also crystallized on its own but

separation is effected by employing an aqueous detergent solution & centrifuges.

◦ Crystallization step is similar to the previous description but the crystal form is less critical because of the mean of separation.

◦ A continuous supply of slurry mixed with a detergent solution (sodium lauryl sulphate and magnesium sulphate) is pumped to the crystallizer.

Detergent ProcessDetergent Process◦ The solutions displace the oil from the

surface of the stearin crystals so that on centrifuging, the olein is discharged as the oil phase and stearin forms part of the aqueous phase.

◦ The aqueous is heated to 90 – 110 °C to break away the stearin from the emulsion and then cooled to 90°C and centrifuged to recover the stearin. The detergent is recycled to the plant.

Solvent processSolvent processThe first step is crystallizing the oil in

solvent. The most common type of solvents used are hexane and acetone.

The mixture of solvent and oil are in the process with chilled water or brine.

Brine is used when a very low temperature of crystallization step is needed.

Vacuum suction is used to separate olein and stearin (filteration).

Lastly the two mixtures are sent to solvent recovery plants where the solvent are separated from oil and recycled. The yield of olein will be in the range of 80% - 83%.