The residue from the press consists of a mixture of fibre and palm nuts. The nuts are separated from the fibre by hand in the small-scale operations. The sorted fibre is covered and allowed to heat, using its own internal exothermic reactions, for about two or three days. The fibre is then pressed in spindle presses to recover a second grade (technical) oil that is used normally in soap-making. The nuts are usually dried and sold to other operators who process them into palm kernel oil. The sorting operation is usually reserved for the youth and elders in the village in a deliberate effort to help them earn some income.
Large-scale mills use the recovered fibre and nutshells to fire the steam boilers. The super-heated steam is then used to drive turbines to generate electricity for the mill. For this reason it makes economic sense to recover the fibre and to shell the palm nuts. In the large-scale kernel recovery process, the nuts contained in the press cake are separated from the fibre in a depericarper. They are then dried and cracked in centrifugal crackers to release the kernels (Fig. 13, 14, 15, 16). The kernels are normally separated from the shells using a combination of winnowing and hydrocyclones. The kernels are then dried in silos to a moisture content of about 7 percent before packing.
During the nut cracking process some of the kernels are broken. The rate of FFA increase is much faster in broken kernels than in whole kernels. Breakage of kernels should therefore be kept as low as possible, given other processing considerations.
Palm Kernel Oil Expellers
The kernels are further processed in palm kernel oil extraction plant to produce palm kernel oil (PKO) and palm kernel cake (PKC). Finally the residue is taken in the form of cakes which is made up of fibres and nuts.
Cake Breaker Conveyor
The cake from the press become a dense well compacted mass that need to be broken up before separation. Here, the cake breaker conveyor functions to deliver the fibre and nut that has been squeezed from the press to the air separation column. It also functions to loosen the press cake to separate the nuts from the fibre. If the fibre and nut are not separate, the fibre will follow the nut to the drum can cause the machine to jam. The is a “L” shape paddles locate on the rotating shaft. The movement of the paddles opens up the fibre and loosen it from the nuts and keeps the fibre in a state of agitation so the conveyor needed to be cover on the side and the top to prevent spillage. A certain amount of moisture will be lost by evaporation as the loosened fibre passing along the cake breaker conveyor towards the nut separator.
To break Palm Kernel Cake, Shell and Copra into small desired particles. It uses the principle of swinging hammers and perforated screen to shear a lumpy object into small chips. It has widely been used in Palm Kernel Crushing Plant to shear Palm Kernel Meal and Palm Kernel Shell into small chips.