Palm Kernel Oil Manufacturing Process

Palm tree originated in the tropical rain forest region of West Africa. The palm tree are grown in Cameroon, Cote d’Ivoire, Ghana, Liberia, Nigeria, Sierra Leone, Togo, Angola, Congo. Palm fruit or palm kernel for edible oil has been processed in Africa for thousands of years, and the oil produced, highly colored and fragrant, is an essential ingredient in one of the traditional African cuisine.

PALM KERNEL OIL PROCESSING PROCESS

Mechanical extraction processes are suitable for both small, medium and large capacity operations. The basic steps are :

• Palm Nut Cracking & Shell Separation Unit
• Palm kernel Mechanical Pressing Unit

Palm Nut Cracking & Shell Separation Unit

Palm Nut is one of the byproduct of Palm Oil Extraction Plants. These Nuts comprise of about 50% Palm Kernel. Proper Separation Technique is necessary to recover the kernels from these nuts.

Ripple Mills are used to crack the Palm nuts. The nuts enter from top of the mill and are impacted several times between the stationary plates and turning rotor. The impact from the rotor cracks the nuts. The output from the Ripple Mill is a mixture of kernels and Shells.

After cracking, next step is the separation of Palm Kernels and Shells. Since the density of kernels & Shells is almost the same, it is difficult to separate it by gravity or Air. A Clay-bath is proven to be the best solution for separation of kernels and shells.

The clay-bath uses a clay solution that is maintained at a pre-determined density.When the cracked mixture is admitted into the clay-bath, the denser shells will sink to the bottom while the less dense kernels will float. They are carried along by the solution to the respective outlets and then to the vibrating screen which is partitioned to receive the kernel and the shell in separate compartments thus allowing the solution to flow through the stainless steel mesh and back to the bottom tank while kernel and shell are being screened and exit from the end of the screen, hence the clay solution is circulated and re-used. An inbuilt stirrer is used to homogenize the solution.

After separation, the kernels are wet and hence need to be dried before being sent to the pressing unit. For this, we use hot Air driers that run either on manual burning of firewood / shells in a furnace or using a steam boiler.

BLOCK DIAGRAM FOR PALM NUT CRACKING AND SHELL SEPARATION

Palm Kernel Mechanical Pressing Unit

The palm kernels are subjected to cleaning in a seed cleaner. It is a Vibrating screen unit for separating trash, impurities from the kernels.

The cleaned Kernels are fed to a palm kernel oil expeller machine, which consists of a main shaft and worms, which rotates within a stationary perforated cylinder called a cage or barrel. As the main shaft turns, there is a decrease in volume resulting in pressure in the cage. The expelled kernel oil flows through the slots distributed over the barrel circumference. The oilcake leaves the extraction machine through an adjustable cone and is then delivered to the second pressing

Because of their high oil content, Palm kernels have to be subjected to 2 stage pressing for maximum oil yield. The residue from First Stage Press is then transferred to a second palm kernel oil expeller machine for final crushing.

The Oil &foots collected from both the First & Second Stage Pressing is delivered to the crude oil Filtering section.

The Oil and Foots Mixture is passed either through the vibro separator or Screening tank which separate foots from the expelled oil.

The separated foots are recycled back to the press. The Pre-cleaned oil is then pumped into a filter press to remove the remaining solids and fines to produce clean oil before the storage.

BLOCK DIAGRAM FOR PALM KERNEL OIL MILL UNIT