Key Processes in the Production of Palm Oil

2.1 Production of Fresh Fruit Bunches (FFB)

The key sub-processes involved in the development of plantations for the production of fresh fruit bunches (FFB) are shown in Figure 3 and the main activities for each step are summarised below:

Figure 3: Processes in the Production of Fresh Fruit Bunches

Planning Phase for the development of new plantations would involve the conduct for feasibility studies and an environment impact assessment (EIA) if the area to be developed is primary or secondary forest in excess of 500 hectares. An EIA is also required if the development involves changes in the types of agricultural use of land in excess of 500 hectares.

       

Figure 4: NREB’s EIA Process     

                                                 

        

The EIA study would facilitate the identification potential environmental and social impacts and development of management plans to mitigate the adverse effects. The process for the approval of EIA reports is shown in Figure 4 which is based on the approach adopted by the Natural Resources and Environment Board, Sarawak.

Nursery Establishment commences as soon as the land is found to be suitable and approved by the respective agencies for development to proceed. Good quality DxP seedlings are raised in a polybag nursery for about 12 months. Good nursery practices such as adequate watering, manuring and culling of seedlings with undesirable characteristics are essential for the production of vigorous planting materials. A culling rate of up to 25% is commonly practised in well managed nurseries.

Site Preparation include land survey, clearing of existing vegetation, establishment of a road and field drainage system, soil conservation measures such as terracing, conservation bunds and silt pits and sowing of leguminous cover crops. From the early 1990s, the zero burning technique for land clearing, from logged-over forest areas and replanting from various plantation crops.

Field Establishment activities are lining, holing and planting of polybag oil palm seedlings at density of 136 to 148 palms per ha, depending on the soil type. It is important that effort is made to obtain full ground coverage by leguminous cover crops such as Pueraria javanica and Calopogonium caeruleum to minimise soil loss through runoff as well as to improve the soil properties through nitrogen fixation. (Plate 6)

          

Plate 6: Immature oil palm with full cover of leguminous cover crops.

        

Field Maintenance operations include weeding, water management, pruning, pest and disease management and manuring. Integrated pest management involving a mix of cultural, physical, chemical and biological control approaches to minimise crop losses to pests is commonly adopted in plantations. Examples of biological control measures applied include the use of baculovirus and Metarhizium anisopliae to control the rhinoceros beetle (Oryctes rhinoceros), control of leaf-eating bagworms and nettle caterpillars by their natural predators and parasitoids and the use of barn owls (Tyto alba) (Plates 7 and 8) as the biological agent to control rats. (Golden Hope Plantations Berhad, 1997). As the cost of fertilisers is the major component of field upkeep expenditure, plantation companies generally undertake soil and foliar analyses of individual fields regularly to assess their nutritional status and determine the appropriate types and quantities of fertilisers required for optimal palm development and production.

                                              

 

  Plate 7: Barn owls for rat control

                 

 

Plate 8: Stakeholder advisory booklet on

integrated pest management

Harvesting and Collection

Harvesting of FFB commences between 24 to 30 months after field planting, depending on the soil type and agronomic and management inputs. Harvesting is done manually, using a chisel in young palms and a sickle mounted on a bamboo or aluminum pole in taller palms (Plate 9)

Various systems for in-field collection of FFB and transportation to the palm oil mill. In view of increasing shortage of workers as well as the need to increase worker productivity, mechanised approaches have been adopted by plantations, an example being the tractor-mounted ‘grabber’ (Plate 10).

Replanting. The economic cycle of the oil palm is about 25

 

Plate 9: Harvesting of FFB

Plate 10: Tractor mounted ‘grabber’

years, after which the old stand is replanted. The zero burning technique of replanting is now common commercial practice. However, in some situations, plantations consider underplanting, whereby new seedlings are planted under the old palms which are thinned out progressively to allow the development of the new stand.

2.2 Production of Crude Palm Oil (CPO) and Palm Kernel (PK)

After harvesting, it is important that the fresh fruit bunches (FFB) are processed as soon as possible to prevent a rapid rise in free fatty acids (FFA) which could adversely affect the quality of the crude palm oil (CPO). Palm oil mills are generally located in the plantations to facilitate timely transportation and effective processing of FFB. In 2001, there were 352 palm oil mills in Malaysia (Table 10), of which about 70% were located in Peninsular Malaysia.

Table 10: Number of Oil Mills, Refineries and Palm Kernel Crushing Factories in Operation in 2001 in Malaysia

Region	Oil Mills		Refineries		Crushing Factories
	No	Capacity1	No	Capacity2	No	Capacity3
P. Malaysia	244	45,373,720	38	10,952,900	30	3,254,600
Sabah Sarawak	89 19	18,750,600 3,620,400	9	4,596,500	8	1,057,500
Malaysia	352	67,744,720	47	15,549,400	38	4,312,100

Source: MPOB                                      Capacity:                      1. Tonnes FFB / year

2.   Tonnes CPO / year

3.   Tonnes Palm Kernel /year

The palm oil milling process (Figure 5) involves the physical extraction of palm products namely, crude palm oil and palm kernel from the FFB. The process begins with sterilisation of the FFB. The fruit bunches are steamed in pressurised vessels up to 3 bars to arrest the formation of free fatty acids and prepare the fruits for subsequent sub-processes.

The sterilised bunches are then stripped of the fruitlets in a rotating drum thresher. The stripped bunches or empty fruit bunches (EFB) are transported to the plantation for mulching while the fruitlets are conveyed to the press digesters.

In the digesters, the fruits are heated using live steam and continuously stirred to loosen the oil-bearing mesocarp from the nuts as well as to break open the oil cells present in the mesocarp. The digested mash is then pressed, extracting the oil by means of screw presses. The press cake is then conveyed to the kernel plant where the kernels are recovered.

The oil from the press is diluted and pumped to vertical clarifier tanks. The clarified oil is then fed to purifiers to remove dirt and moisture before being dried further in the vacuum drier. The clean and dry oil is ready for storage and dispatch.

The sludge from the clarifier sediment is fed into bowl centrifuges for further oil recovery. The recovered oil is recycled to the clarifiers while the water/sludge mixture which is referred to as Palm Oil Mill Effluent (POME) is treated in the effluent treatment plant.(ETP).

The press cake is conveyed to the depericarper where the fibre and nuts are separated. Fibre is burned as fuel in the boiler to generate steam. The nuts are cracked and the shell and kernel are separated by means of a winnower and hydro-cyclone. The clean kernels are dried prior to storage.

Figure 5: Palm Oil Milling Process

2.3 Production of Refined Edible Palm Oil

About 80% of the national production of crude palm oil is used for food purposes, mainly as cooking oils. The CPO produced by the mills have to be refined to meet the industry’s and international standards (FAO’s Codex Alimentarius) for edible oils. The production of refined oil is undertaken in 57 refineries in Malaysia (Table 10) with a total refining capacity of 15.5 million tonnes CPO per year.

The refining process removes free fatty acids, phosphatides, odouriferous matter, water as well as impurities such as dirt and traces of metals from the CPO; the objective being to produce an edible oil of consistent quality that meets industry’s standards and satisfies customer requirements particularly in respect of FFA, moisture and impurities, Iodine Value, Peroxide Value, melting point, colour and flavour. The refined oil must tasteless and have a bland flavour.

CPO is processed by either physical or chemical refining to produce either refined, bleached and deodourised palm oil (RBDPO) or neutralised, bleached and deodourised palm oil (NBDPO). These are subjected to fractionation to obtain the respective liquid olein fraction and the solid stearin fraction. (Figure 6). Of the two processes, physical refining is the predominant approach adopted by the refineries as it is simpler, less capital intensive, more efficient and produces a lower effluent load.

Physical or steam refining begins with degumming when the CPO is treated with food grade phosphoric acid or citric acid to remove natural gums in the form of phosphatides , followed by bleaching with activated earth (Fuller’s Earth) under vacuum to remove colouring matters as well as to adsorb any metal ions. The treated oil is then heated to 240 C - 260 C under 2- 6 mm Hg (MEOMA, 2002) for simultaneous deacidification and deodorisation. The FFA is stripped off by live steam and is recovered together with the entrained oil is as palm fatty acid distillate. The steam distillation process also removes odours and off-flavors from the CPO (‘Deodorisation’). The oil is then cooled to 55°C before polishing.

In the chemical refining process, the FFA present in CPO is removed by neutralisation with caustic soda (sodium hydroxide), the concentration of the latter being dependent on the quality of the CPO feedstock. This chemical reaction produces neutralised CPO and a soap stock; the latter is separated from the oil by a high-speed separator. The neutralised oil is subjected to earth bleaching to remove colour pigments and metal ions followed by deodorisation - steam distillation under vacuum to remove odoriferous matters such as aldehydes and ketones.

The refined oil contains triglycerides of various compositions and melting points, the main fractions being palm olein and palm stearin. These fractions can be separated by dry fractionation, detergent fractionation and solvent fractionation. Dry fractionation is

commonly used whereby the refined oil is allowed to crystallise under controlled temperature and the resultant slurry is pumped through a membrane filter press to obtain the liquid olein fraction and the solid stearin portion. The olein could also be fractionated for a second time (‘double fractionation’) to produce a ‘super olein’ and a solid palm mid-fraction (PMF) which is the feedstock for production of specialty fats and other products.

Figure 6: Palm Oil Refining Process